Let free_all() helper return the number of freed elements.
It's not used in this patch, but helps in debug/development of bpf_mem_alloc.
For example this diff for __free_rcu():
- free_all(llist_del_all(&c->waiting_for_gp_ttrace), !!c->percpu_size);
+ printk("cpu %d freed %d objs after tasks trace\n", raw_smp_processor_id(),
+ free_all(llist_del_all(&c->waiting_for_gp_ttrace), !!c->percpu_size));
would show how busy RCU tasks trace is.
In artificial benchmark where one cpu is allocating and different cpu is freeing
the RCU tasks trace won't be able to keep up and the list of objects
would keep growing from thousands to millions and eventually OOMing.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/bpf/20230706033447.54696-4-alexei.starovoitov@gmail.com
bpf_get_smp_processor_id() helper returns current CPU on which BPF
program runs. It can't return value that is bigger than maximum allowed
number of CPUs (minus one, due to zero indexing). Teach BPF verifier to
recognize that. This makes it possible to use bpf_get_smp_processor_id()
result to index into arrays without extra checks, as demonstrated in
subsequent selftests/bpf patch.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230711232400.1658562-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
By introducing support for ->fill_link_info to the perf_event link, users
gain the ability to inspect it using `bpftool link show`. While the current
approach involves accessing this information via `bpftool perf show`,
consolidating link information for all link types in one place offers
greater convenience. Additionally, this patch extends support to the
generic perf event, which is not currently accommodated by
`bpftool perf show`. While only the perf type and config are exposed to
userspace, other attributes such as sample_period and sample_freq are
ignored. It's important to note that if kptr_restrict is not permitted, the
probed address will not be exposed, maintaining security measures.
A new enum bpf_perf_event_type is introduced to help the user understand
which struct is relevant.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230709025630.3735-9-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add a common helper bpf_copy_to_user(), which will be used at multiple
places.
No functional change.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230709025630.3735-8-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add another column to the /sys/fs/bpf/maps.debug iterator to display
cur_entries, the current number of entries in the map as is returned
by the bpf_map_sum_elem_count kfunc. Also fix formatting.
Example:
# cat /sys/fs/bpf/maps.debug
id name max_entries cur_entries
2 iterator.rodata 1 0
125 cilium_auth_map 524288 666
126 cilium_runtime_ 256 0
127 cilium_signals 32 0
128 cilium_node_map 16384 1344
129 cilium_events 32 0
...
Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
Link: https://lore.kernel.org/r/20230706133932.45883-5-aspsk@isovalent.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Initialize and utilize the per-cpu insertions/deletions counters for hash-based
maps. Non-trivial changes only apply to the preallocated maps for which the
{inc,dec}_elem_count functions are not called, as there's no need in counting
elements to sustain proper map operations.
To increase/decrease percpu counters for preallocated maps we add raw calls to
the bpf_map_{inc,dec}_elem_count functions so that the impact is minimal. For
dynamically allocated maps we add corresponding calls to the existing
{inc,dec}_elem_count functions.
Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
Link: https://lore.kernel.org/r/20230706133932.45883-4-aspsk@isovalent.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
A bpf_map_sum_elem_count kfunc was added to simplify getting the sum of the map
per-cpu element counters. If a map doesn't implement the counter, then the
function will always return 0.
Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
Link: https://lore.kernel.org/r/20230706133932.45883-3-aspsk@isovalent.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The check_max_stack_depth pass happens after the verifier's symbolic
execution, and attempts to walk the call graph of the BPF program,
ensuring that the stack usage stays within bounds for all possible call
chains. There are two cases to consider: bpf_pseudo_func and
bpf_pseudo_call. In the former case, the callback pointer is loaded into
a register, and is assumed that it is passed to some helper later which
calls it (however there is no way to be sure), but the check remains
conservative and accounts the stack usage anyway. For this particular
case, asynchronous callbacks are skipped as they execute asynchronously
when their corresponding event fires.
The case of bpf_pseudo_call is simpler and we know that the call is
definitely made, hence the stack depth of the subprog is accounted for.
However, the current check still skips an asynchronous callback even if
a bpf_pseudo_call was made for it. This is erroneous, as it will miss
accounting for the stack usage of the asynchronous callback, which can
be used to breach the maximum stack depth limit.
Fix this by only skipping asynchronous callbacks when the instruction is
not a pseudo call to the subprog.
Fixes: 7ddc80a476 ("bpf: Teach stack depth check about async callbacks.")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230705144730.235802-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The theoretical maximum size of ring buffer is about 64GB, but now the
size of ring buffer is specified by max_entries in bpf_attr and its
maximum value is (4GB - 1), and it won't be possible for overflow.
So just remove the unnecessary size check in ringbuf_map_alloc() but
keep the comments for possible extension in future.
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Closes: https://lore.kernel.org/bpf/9c636a63-1f3d-442d-9223-96c2dccb9469@moroto.mountain
Link: https://lore.kernel.org/bpf/20230704074014.216616-1-houtao@huaweicloud.com
__register_btf_kfunc_id_set() assumes .BTF to be part of the module's .ko
file if CONFIG_DEBUG_INFO_BTF is enabled. If that's not the case, the
function prints an error message and return an error. As a result, such
modules cannot be loaded.
However, the section could be stripped out during a build process. It would
be better to let the modules loaded, because their basic functionalities
have no problem [0], though the BTF functionalities will not be supported.
Make the function to lower the level of the message from error to warn, and
return no error.
[0] https://lore.kernel.org/bpf/20220219082037.ow2kbq5brktf4f2u@apollo.legion
Fixes: c446fdacb1 ("bpf: fix register_btf_kfunc_id_set for !CONFIG_DEBUG_INFO_BTF")
Reported-by: Alexander Egorenkov <Alexander.Egorenkov@ibm.com>
Suggested-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/87y228q66f.fsf@oc8242746057.ibm.com
Link: https://lore.kernel.org/bpf/20220219082037.ow2kbq5brktf4f2u@apollo.legion
Link: https://lore.kernel.org/bpf/20230701171447.56464-1-sj@kernel.org
It is impossible to use skb_frag_t in the tracing program. Resolve typedefs
when walking structs.
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20230626212522.2414485-1-sdf@google.com
The -target option has been deprecated since clang 3.4 in 2013. Therefore, use
the preferred --target=bpf form instead. This also matches how we use --target=
in scripts/Makefile.clang.
Signed-off-by: Fangrui Song <maskray@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Link: 274b6f0c87
Link: https://lore.kernel.org/bpf/20230624001856.1903733-1-maskray@google.com
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:
====================
pull-request: bpf-next 2023-06-23
We've added 49 non-merge commits during the last 24 day(s) which contain
a total of 70 files changed, 1935 insertions(+), 442 deletions(-).
The main changes are:
1) Extend bpf_fib_lookup helper to allow passing the route table ID,
from Louis DeLosSantos.
2) Fix regsafe() in verifier to call check_ids() for scalar registers,
from Eduard Zingerman.
3) Extend the set of cpumask kfuncs with bpf_cpumask_first_and()
and a rework of bpf_cpumask_any*() kfuncs. Additionally,
add selftests, from David Vernet.
4) Fix socket lookup BPF helpers for tc/XDP to respect VRF bindings,
from Gilad Sever.
5) Change bpf_link_put() to use workqueue unconditionally to fix it
under PREEMPT_RT, from Sebastian Andrzej Siewior.
6) Follow-ups to address issues in the bpf_refcount shared ownership
implementation, from Dave Marchevsky.
7) A few general refactorings to BPF map and program creation permissions
checks which were part of the BPF token series, from Andrii Nakryiko.
8) Various fixes for benchmark framework and add a new benchmark
for BPF memory allocator to BPF selftests, from Hou Tao.
9) Documentation improvements around iterators and trusted pointers,
from Anton Protopopov.
10) Small cleanup in verifier to improve allocated object check,
from Daniel T. Lee.
11) Improve performance of bpf_xdp_pointer() by avoiding access
to shared_info when XDP packet does not have frags,
from Jesper Dangaard Brouer.
12) Silence a harmless syzbot-reported warning in btf_type_id_size(),
from Yonghong Song.
13) Remove duplicate bpfilter_umh_cleanup in favor of umd_cleanup_helper,
from Jarkko Sakkinen.
14) Fix BPF selftests build for resolve_btfids under custom HOSTCFLAGS,
from Viktor Malik.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (49 commits)
bpf, docs: Document existing macros instead of deprecated
bpf, docs: BPF Iterator Document
selftests/bpf: Fix compilation failure for prog vrf_socket_lookup
selftests/bpf: Add vrf_socket_lookup tests
bpf: Fix bpf socket lookup from tc/xdp to respect socket VRF bindings
bpf: Call __bpf_sk_lookup()/__bpf_skc_lookup() directly via TC hookpoint
bpf: Factor out socket lookup functions for the TC hookpoint.
selftests/bpf: Set the default value of consumer_cnt as 0
selftests/bpf: Ensure that next_cpu() returns a valid CPU number
selftests/bpf: Output the correct error code for pthread APIs
selftests/bpf: Use producer_cnt to allocate local counter array
xsk: Remove unused inline function xsk_buff_discard()
bpf: Keep BPF_PROG_LOAD permission checks clear of validations
bpf: Centralize permissions checks for all BPF map types
bpf: Inline map creation logic in map_create() function
bpf: Move unprivileged checks into map_create() and bpf_prog_load()
bpf: Remove in_atomic() from bpf_link_put().
selftests/bpf: Verify that check_ids() is used for scalars in regsafe()
bpf: Verify scalar ids mapping in regsafe() using check_ids()
selftests/bpf: Check if mark_chain_precision() follows scalar ids
...
====================
Link: https://lore.kernel.org/r/20230623211256.8409-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
We currently allow to create perf link for program with
expected_attach_type == BPF_TRACE_KPROBE_MULTI.
This will cause crash when we call helpers like get_attach_cookie or
get_func_ip in such program, because it will call the kprobe_multi's
version (current->bpf_ctx context setup) of those helpers while it
expects perf_link's current->bpf_ctx context setup.
Making sure that we use BPF_TRACE_KPROBE_MULTI expected_attach_type
only for programs attaching through kprobe_multi link.
Fixes: ca74823c6e ("bpf: Add cookie support to programs attached with kprobe multi link")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20230618131414.75649-1-jolsa@kernel.org
When building a kernel with LLVM=1, LLVM_IAS=0 and CONFIG_KASAN=y, LLVM
leaves DWARF tags for the "asan.module_ctor" & co symbols. In turn,
pahole creates BTF_KIND_FUNC entries for these and this makes the BTF
metadata validation fail because they contain a dot.
In a dramatic turn of event, this BTF verification failure can cause
the netfilter_bpf initialization to fail, causing netfilter_core to
free the netfilter_helper hashmap and netfilter_ftp to trigger a
use-after-free. The risk of u-a-f in netfilter will be addressed
separately but the existence of "asan.module_ctor" debug info under some
build conditions sounds like a good enough reason to accept functions
that contain dots in BTF.
Although using only LLVM=1 is the recommended way to compile clang-based
kernels, users can certainly do LLVM=1, LLVM_IAS=0 as well and we still
try to support that combination according to Nick. To clarify:
- > v5.10 kernel, LLVM=1 (LLVM_IAS=0 is not the default) is recommended,
but user can still have LLVM=1, LLVM_IAS=0 to trigger the issue
- <= 5.10 kernel, LLVM=1 (LLVM_IAS=0 is the default) is recommended in
which case GNU as will be used
Fixes: 1dc9285184 ("bpf: kernel side support for BTF Var and DataSec")
Signed-off-by: Florent Revest <revest@chromium.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Cc: Yonghong Song <yhs@meta.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/bpf/20230615145607.3469985-1-revest@chromium.org
Move out flags validation and license checks out of the permission
checks. They were intermingled, which makes subsequent changes harder.
Clean this up: perform straightforward flag validation upfront, and
fetch and check license later, right where we use it. Also consolidate
capabilities check in one block, right after basic attribute sanity
checks.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20230613223533.3689589-5-andrii@kernel.org
This allows to do more centralized decisions later on, and generally
makes it very explicit which maps are privileged and which are not
(e.g., LRU_HASH and LRU_PERCPU_HASH, which are privileged HASH variants,
as opposed to unprivileged HASH and HASH_PERCPU; now this is explicit
and easy to verify).
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20230613223533.3689589-4-andrii@kernel.org
Currently find_and_alloc_map() performs two separate functions: some
argument sanity checking and partial map creation workflow hanling.
Neither of those functions are self-sufficient and are augmented by
further checks and initialization logic in the caller (map_create()
function). So unify all the sanity checks, permission checks, and
creation and initialization logic in one linear piece of code in
map_create() instead. This also make it easier to further enhance
permission checks and keep them located in one place.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20230613223533.3689589-3-andrii@kernel.org
Make each bpf() syscall command a bit more self-contained, making it
easier to further enhance it. We move sysctl_unprivileged_bpf_disabled
handling down to map_create() and bpf_prog_load(), two special commands
in this regard.
Also swap the order of checks, calling bpf_capable() only if
sysctl_unprivileged_bpf_disabled is true, avoiding unnecessary audit
messages.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20230613223533.3689589-2-andrii@kernel.org
bpf_free_inode() is invoked as a RCU callback. Usually RCU callbacks are
invoked within softirq context. By setting rcutree.use_softirq=0 boot
option the RCU callbacks will be invoked in a per-CPU kthread with
bottom halves disabled which implies a RCU read section.
On PREEMPT_RT the context remains fully preemptible. The RCU read
section however does not allow schedule() invocation. The latter happens
in mutex_lock() performed by bpf_trampoline_unlink_prog() originated
from bpf_link_put().
It was pointed out that the bpf_link_put() invocation should not be
delayed if originated from close(). It was also pointed out that other
invocations from within a syscall should also avoid the workqueue.
Everyone else should use workqueue by default to remain safe in the
future (while auditing the code, every caller was preemptible except for
the RCU case).
Let bpf_link_put() use the worker unconditionally. Add
bpf_link_put_direct() which will directly free the resources and is used
by close() and from within __sys_bpf().
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230614083430.oENawF8f@linutronix.de
Make sure that the following unsafe example is rejected by verifier:
1: r9 = ... some pointer with range X ...
2: r6 = ... unbound scalar ID=a ...
3: r7 = ... unbound scalar ID=b ...
4: if (r6 > r7) goto +1
5: r6 = r7
6: if (r6 > X) goto ...
--- checkpoint ---
7: r9 += r7
8: *(u64 *)r9 = Y
This example is unsafe because not all execution paths verify r7 range.
Because of the jump at (4) the verifier would arrive at (6) in two states:
I. r6{.id=b}, r7{.id=b} via path 1-6;
II. r6{.id=a}, r7{.id=b} via path 1-4, 6.
Currently regsafe() does not call check_ids() for scalar registers,
thus from POV of regsafe() states (I) and (II) are identical. If the
path 1-6 is taken by verifier first, and checkpoint is created at (6)
the path [1-4, 6] would be considered safe.
Changes in this commit:
- check_ids() is modified to disallow mapping multiple old_id to the
same cur_id.
- check_scalar_ids() is added, unlike check_ids() it treats ID zero as
a unique scalar ID.
- check_scalar_ids() needs to generate temporary unique IDs, field
'tmp_id_gen' is added to bpf_verifier_env::idmap_scratch to
facilitate this.
- regsafe() is updated to:
- use check_scalar_ids() for precise scalar registers.
- compare scalar registers using memcmp only for explore_alu_limits
branch. This simplifies control flow for scalar case, and has no
measurable performance impact.
- check_alu_op() is updated to avoid generating bpf_reg_state::id for
constant scalar values when processing BPF_MOV. ID is needed to
propagate range information for identical values, but there is
nothing to propagate for constants.
Fixes: 75748837b7 ("bpf: Propagate scalar ranges through register assignments.")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230613153824.3324830-4-eddyz87@gmail.com
Change mark_chain_precision() to track precision in situations
like below:
r2 = unknown value
...
--- state #0 ---
...
r1 = r2 // r1 and r2 now share the same ID
...
--- state #1 {r1.id = A, r2.id = A} ---
...
if (r2 > 10) goto exit; // find_equal_scalars() assigns range to r1
...
--- state #2 {r1.id = A, r2.id = A} ---
r3 = r10
r3 += r1 // need to mark both r1 and r2
At the beginning of the processing of each state, ensure that if a
register with a scalar ID is marked as precise, all registers sharing
this ID are also marked as precise.
This property would be used by a follow-up change in regsafe().
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230613153824.3324830-2-eddyz87@gmail.com
When subprograms are in use, the main program is not jit'd after the
subprograms because jit_subprogs sets a value for prog->bpf_func upon
success. Subsequent calls to the JIT are bypassed when this value is
non-NULL. This leads to a situation where the main program and its
func[0] counterpart are both in the bpf kallsyms tree, but only func[0]
has an extable. Extables are only created during JIT. Now there are
two nearly identical program ksym entries in the tree, but only one has
an extable. Depending upon how the entries are placed, there's a chance
that a fault will call search_extable on the aux with the NULL entry.
Since jit_subprogs already copies state from func[0] to the main
program, include the extable pointer in this state duplication.
Additionally, ensure that the copy of the main program in func[0] is not
added to the bpf_prog_kallsyms table. Instead, let the main program get
added later in bpf_prog_load(). This ensures there is only a single
copy of the main program in the kallsyms table, and that its tag matches
the tag observed by tooling like bpftool.
Cc: stable@vger.kernel.org
Fixes: 1c2a088a66 ("bpf: x64: add JIT support for multi-function programs")
Signed-off-by: Krister Johansen <kjlx@templeofstupid.com>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/6de9b2f4b4724ef56efbb0339daaa66c8b68b1e7.1686616663.git.kjlx@templeofstupid.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
We currently export the bpf_cpumask_any() and bpf_cpumask_any_and()
kfuncs. Intuitively, one would expect these to choose any CPU in the
cpumask, but what they actually do is alias to cpumask_first() and
cpmkas_first_and().
This is useless given that we already export bpf_cpumask_first() and
bpf_cpumask_first_and(), so this patch replaces them with kfuncs that
call cpumask_any_distribute() and cpumask_any_and_distribute(), which
actually choose any CPU from the cpumask (or the AND of two cpumasks for
the latter).
Signed-off-by: David Vernet <void@manifault.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20230610035053.117605-3-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
We currently provide bpf_cpumask_first(), bpf_cpumask_any(), and
bpf_cpumask_any_and() kfuncs. bpf_cpumask_any() and
bpf_cpumask_any_and() are confusing misnomers in that they actually just
call cpumask_first() and cpumask_first_and() respectively.
We'll replace them with bpf_cpumask_any_distribute() and
bpf_cpumask_any_distribute_and() kfuncs in a subsequent patch, so let's
ensure feature parity by adding a bpf_cpumask_first_and() kfunc to
account for bpf_cpumask_any_and() being removed.
Signed-off-by: David Vernet <void@manifault.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20230610035053.117605-1-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This function is only used when CONFIG_BPF_JIT_ALWAYS_ON is disabled, but
CONFIG_BPF_SYSCALL is enabled. When both are turned off, the prototype is
missing but the unused function is still compiled, as seen from this W=1
warning:
[...]
kernel/bpf/core.c:2075:6: error: no previous prototype for 'bpf_patch_call_args' [-Werror=missing-prototypes]
[...]
Add a matching #ifdef for the definition to leave it out.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20230602135128.1498362-1-arnd@kernel.org
Cross-merge networking fixes after downstream PR.
Conflicts:
net/sched/sch_taprio.c
d636fc5dd6 ("net: sched: add rcu annotations around qdisc->qdisc_sleeping")
dced11ef84 ("net/sched: taprio: don't overwrite "sch" variable in taprio_dump_class_stats()")
net/ipv4/sysctl_net_ipv4.c
e209fee411 ("net/ipv4: ping_group_range: allow GID from 2147483648 to 4294967294")
ccce324dab ("tcp: make the first N SYN RTO backoffs linear")
https://lore.kernel.org/all/20230605100816.08d41a7b@canb.auug.org.au/
No adjacent changes.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The following scenario describes a bug in the verifier where it
incorrectly concludes about equivalent scalar IDs which could lead to
verifier bypass in privileged mode:
1. Prepare a 32-bit rogue number.
2. Put the rogue number into the upper half of a 64-bit register, and
roll a random (unknown to the verifier) bit in the lower half. The
rest of the bits should be zero (although variations are possible).
3. Assign an ID to the register by MOVing it to another arbitrary
register.
4. Perform a 32-bit spill of the register, then perform a 32-bit fill to
another register. Due to a bug in the verifier, the ID will be
preserved, although the new register will contain only the lower 32
bits, i.e. all zeros except one random bit.
At this point there are two registers with different values but the same
ID, which means the integrity of the verifier state has been corrupted.
5. Compare the new 32-bit register with 0. In the branch where it's
equal to 0, the verifier will believe that the original 64-bit
register is also 0, because it has the same ID, but its actual value
still contains the rogue number in the upper half.
Some optimizations of the verifier prevent the actual bypass, so
extra care is needed: the comparison must be between two registers,
and both branches must be reachable (this is why one random bit is
needed). Both branches are still suitable for the bypass.
6. Right shift the original register by 32 bits to pop the rogue number.
7. Use the rogue number as an offset with any pointer. The verifier will
believe that the offset is 0, while in reality it's the given number.
The fix is similar to the 32-bit BPF_MOV handling in check_alu_op for
SCALAR_VALUE. If the spill is narrowing the actual register value, don't
keep the ID, make sure it's reset to 0.
Fixes: 354e8f1970 ("bpf: Support <8-byte scalar spill and refill")
Signed-off-by: Maxim Mikityanskiy <maxim@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Andrii Nakryiko <andrii@kernel.org> # Checked veristat delta
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20230607123951.558971-2-maxtram95@gmail.com
Andrii Nakryiko writes:
And we currently don't have an attach type for NETLINK BPF link.
Thankfully it's not too late to add it. I see that link_create() in
kernel/bpf/syscall.c just bypasses attach_type check. We shouldn't
have done that. Instead we need to add BPF_NETLINK attach type to enum
bpf_attach_type. And wire all that properly throughout the kernel and
libbpf itself.
This adds BPF_NETFILTER and uses it. This breaks uabi but this
wasn't in any non-rc release yet, so it should be fine.
v2: check link_attack prog type in link_create too
Fixes: 84601d6ee6 ("bpf: add bpf_link support for BPF_NETFILTER programs")
Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/CAEf4BzZ69YgrQW7DHCJUT_X+GqMq_ZQQPBwopaJJVGFD5=d5Vg@mail.gmail.com/
Link: https://lore.kernel.org/bpf/20230605131445.32016-1-fw@strlen.de
In reg_type_not_null(), we currently assume that a pointer may be NULL
if it has the PTR_MAYBE_NULL modifier, or if it doesn't belong to one of
several base type of pointers that are never NULL-able. For example,
PTR_TO_CTX, PTR_TO_MAP_VALUE, etc.
It turns out that in some cases, PTR_TO_BTF_ID can never be NULL as
well, though we currently don't specify it. For example, if you had the
following program:
SEC("tc")
long example_refcnt_fail(void *ctx)
{
struct bpf_cpumask *mask1, *mask2;
mask1 = bpf_cpumask_create();
mask2 = bpf_cpumask_create();
if (!mask1 || !mask2)
goto error_release;
bpf_cpumask_test_cpu(0, (const struct cpumask *)mask1);
bpf_cpumask_test_cpu(0, (const struct cpumask *)mask2);
error_release:
if (mask1)
bpf_cpumask_release(mask1);
if (mask2)
bpf_cpumask_release(mask2);
return ret;
}
The verifier will incorrectly fail to load the program, thinking
(unintuitively) that we have a possibly-unreleased reference if the mask
is NULL, because we (correctly) don't issue a bpf_cpumask_release() on
the NULL path.
The reason the verifier gets confused is due to the fact that we don't
explicitly tell the verifier that trusted PTR_TO_BTF_ID pointers can
never be NULL. Basically, if we successfully get past the if check
(meaning both pointers go from ptr_or_null_bpf_cpumask to
ptr_bpf_cpumask), the verifier will correctly assume that the references
need to be dropped on any possible branch that leads to program exit.
However, it will _incorrectly_ think that the ptr == NULL branch is
possible, and will erroneously detect it as a branch on which we failed
to drop the reference.
The solution is of course to teach the verifier that trusted
PTR_TO_BTF_ID pointers can never be NULL, so that it doesn't incorrectly
think it's possible for the reference to be present on the ptr == NULL
branch.
A follow-on patch will add a selftest that verifies this behavior.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230602150112.1494194-1-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
>From commit 282de143ea ("bpf: Introduce allocated objects support"),
With this allocated object with BPF program, (PTR_TO_BTF_ID | MEM_ALLOC)
has been a way of indicating to check the type is the allocated object.
commit d8939cb0a0 ("bpf: Loosen alloc obj test in verifier's
reg_btf_record")
>From the commit, there has been helper function for checking this, named
type_is_ptr_alloc_obj(). But still, some of the code use open code to
retrieve this info. This commit replaces the open code with the
type_is_alloc(), and the type_is_ptr_alloc_obj() function.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230527122706.59315-1-danieltimlee@gmail.com
This patch fixes an incorrect assumption made in the original
bpf_refcount series [0], specifically that the BPF program calling
bpf_refcount_acquire on some node can always guarantee that the node is
alive. In that series, the patch adding failure behavior to rbtree_add
and list_push_{front, back} breaks this assumption for non-owning
references.
Consider the following program:
n = bpf_kptr_xchg(&mapval, NULL);
/* skip error checking */
bpf_spin_lock(&l);
if(bpf_rbtree_add(&t, &n->rb, less)) {
bpf_refcount_acquire(n);
/* Failed to add, do something else with the node */
}
bpf_spin_unlock(&l);
It's incorrect to assume that bpf_refcount_acquire will always succeed in this
scenario. bpf_refcount_acquire is being called in a critical section
here, but the lock being held is associated with rbtree t, which isn't
necessarily the lock associated with the tree that the node is already
in. So after bpf_rbtree_add fails to add the node and calls bpf_obj_drop
in it, the program has no ownership of the node's lifetime. Therefore
the node's refcount can be decr'd to 0 at any time after the failing
rbtree_add. If this happens before the refcount_acquire above, the node
might be free'd, and regardless refcount_acquire will be incrementing a
0 refcount.
Later patches in the series exercise this scenario, resulting in the
expected complaint from the kernel (without this patch's changes):
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 1 PID: 207 at lib/refcount.c:25 refcount_warn_saturate+0xbc/0x110
Modules linked in: bpf_testmod(O)
CPU: 1 PID: 207 Comm: test_progs Tainted: G O 6.3.0-rc7-02231-g723de1a718a2-dirty #371
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
RIP: 0010:refcount_warn_saturate+0xbc/0x110
Code: 6f 64 f6 02 01 e8 84 a3 5c ff 0f 0b eb 9d 80 3d 5e 64 f6 02 00 75 94 48 c7 c7 e0 13 d2 82 c6 05 4e 64 f6 02 01 e8 64 a3 5c ff <0f> 0b e9 7a ff ff ff 80 3d 38 64 f6 02 00 0f 85 6d ff ff ff 48 c7
RSP: 0018:ffff88810b9179b0 EFLAGS: 00010082
RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000000000
RDX: 0000000000000202 RSI: 0000000000000008 RDI: ffffffff857c3680
RBP: ffff88810027d3c0 R08: ffffffff8125f2a4 R09: ffff88810b9176e7
R10: ffffed1021722edc R11: 746e756f63666572 R12: ffff88810027d388
R13: ffff88810027d3c0 R14: ffffc900005fe030 R15: ffffc900005fe048
FS: 00007fee0584a700(0000) GS:ffff88811b280000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005634a96f6c58 CR3: 0000000108ce9002 CR4: 0000000000770ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<TASK>
bpf_refcount_acquire_impl+0xb5/0xc0
(rest of output snipped)
The patch addresses this by changing bpf_refcount_acquire_impl to use
refcount_inc_not_zero instead of refcount_inc and marking
bpf_refcount_acquire KF_RET_NULL.
For owning references, though, we know the above scenario is not possible
and thus that bpf_refcount_acquire will always succeed. Some verifier
bookkeeping is added to track "is input owning ref?" for bpf_refcount_acquire
calls and return false from is_kfunc_ret_null for bpf_refcount_acquire on
owning refs despite it being marked KF_RET_NULL.
Existing selftests using bpf_refcount_acquire are modified where
necessary to NULL-check its return value.
[0]: https://lore.kernel.org/bpf/20230415201811.343116-1-davemarchevsky@fb.com/
Fixes: d2dcc67df9 ("bpf: Migrate bpf_rbtree_add and bpf_list_push_{front,back} to possibly fail")
Reported-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230602022647.1571784-5-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Given the pointer to struct bpf_{rb,list}_node within a local kptr and
the byte offset of that field within the kptr struct, the calculation changed
by this patch is meant to find the beginning of the kptr so that it can
be passed to bpf_obj_drop.
Unfortunately instead of doing
ptr_to_kptr = ptr_to_node_field - offset_bytes
the calculation is erroneously doing
ptr_to_ktpr = ptr_to_node_field - (offset_bytes * sizeof(struct bpf_rb_node))
or the bpf_list_node equivalent.
This patch fixes the calculation.
Fixes: d2dcc67df9 ("bpf: Migrate bpf_rbtree_add and bpf_list_push_{front,back} to possibly fail")
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230602022647.1571784-4-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In verifier.c, fixup_kfunc_call uses struct bpf_insn_aux_data's
kptr_struct_meta field to pass information about local kptr types to
various helpers and kfuncs at runtime. The recent bpf_refcount series
added a few functions to the set that need this information:
* bpf_refcount_acquire
* Needs to know where the refcount field is in order to increment
* Graph collection insert kfuncs: bpf_rbtree_add, bpf_list_push_{front,back}
* Were migrated to possibly fail by the bpf_refcount series. If
insert fails, the input node is bpf_obj_drop'd. bpf_obj_drop needs
the kptr_struct_meta in order to decr refcount and properly free
special fields.
Unfortunately the verifier handling of collection insert kfuncs was not
modified to actually populate kptr_struct_meta. Accordingly, when the
node input to those kfuncs is passed to bpf_obj_drop, it is done so
without the information necessary to decr refcount.
This patch fixes the issue by populating kptr_struct_meta for those
kfuncs.
Fixes: d2dcc67df9 ("bpf: Migrate bpf_rbtree_add and bpf_list_push_{front,back} to possibly fail")
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230602022647.1571784-3-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Commit d937bc3449 ("bpf: make uniform use of array->elem_size
everywhere in arraymap.c") changed array_map_gen_lookup to use
array->elem_size instead of round_up(map->value_size, 8) as the element
size when generating code to access a value in an array map.
array->elem_size, however, is not set by bpf_map_meta_alloc when
initializing an BPF_MAP_TYPE_ARRAY_OF_MAPS or BPF_MAP_TYPE_HASH_OF_MAPS.
This results in array_map_gen_lookup incorrectly outputting code that
always accesses index 0 in the array (as the index will be calculated
via a multiplication with the element size, which is incorrectly set to
0).
Set elem_size on the bpf_array object when allocating an array or hash
of maps to fix this.
Fixes: d937bc3449 ("bpf: make uniform use of array->elem_size everywhere in arraymap.c")
Signed-off-by: Rhys Rustad-Elliott <me@rhysre.net>
Link: https://lore.kernel.org/r/20230602190110.47068-2-me@rhysre.net
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
strlcpy() reads the entire source buffer first. This read may exceed the
destination size limit. This is both inefficient and can lead to linear
read overflows if a source string is not NUL-terminated [1]. This is not
the case here, however, in an effort to remove strlcpy() completely [2],
lets replace strlcpy() here with strscpy(). No return values were used,
so a direct replacement is safe.
[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89
Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/bpf/20230530155659.309657-1-azeemshaikh38@gmail.com
syzbot reported a warning in [1] with the following stacktrace:
WARNING: CPU: 0 PID: 5005 at kernel/bpf/btf.c:1988 btf_type_id_size+0x2d9/0x9d0 kernel/bpf/btf.c:1988
...
RIP: 0010:btf_type_id_size+0x2d9/0x9d0 kernel/bpf/btf.c:1988
...
Call Trace:
<TASK>
map_check_btf kernel/bpf/syscall.c:1024 [inline]
map_create+0x1157/0x1860 kernel/bpf/syscall.c:1198
__sys_bpf+0x127f/0x5420 kernel/bpf/syscall.c:5040
__do_sys_bpf kernel/bpf/syscall.c:5162 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5160 [inline]
__x64_sys_bpf+0x79/0xc0 kernel/bpf/syscall.c:5160
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
With the following btf
[1] DECL_TAG 'a' type_id=4 component_idx=-1
[2] PTR '(anon)' type_id=0
[3] TYPE_TAG 'a' type_id=2
[4] VAR 'a' type_id=3, linkage=static
and when the bpf_attr.btf_key_type_id = 1 (DECL_TAG),
the following WARN_ON_ONCE in btf_type_id_size() is triggered:
if (WARN_ON_ONCE(!btf_type_is_modifier(size_type) &&
!btf_type_is_var(size_type)))
return NULL;
Note that 'return NULL' is the correct behavior as we don't want
a DECL_TAG type to be used as a btf_{key,value}_type_id even
for the case like 'DECL_TAG -> STRUCT'. So there
is no correctness issue here, we just want to silence warning.
To silence the warning, I added DECL_TAG as one of kinds in
btf_type_nosize() which will cause btf_type_id_size() returning
NULL earlier without the warning.
[1] https://lore.kernel.org/bpf/000000000000e0df8d05fc75ba86@google.com/
Reported-by: syzbot+958967f249155967d42a@syzkaller.appspotmail.com
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20230530205029.264910-1-yhs@fb.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:
====================
pull-request: bpf-next 2023-05-26
We've added 54 non-merge commits during the last 10 day(s) which contain
a total of 76 files changed, 2729 insertions(+), 1003 deletions(-).
The main changes are:
1) Add the capability to destroy sockets in BPF through a new kfunc,
from Aditi Ghag.
2) Support O_PATH fds in BPF_OBJ_PIN and BPF_OBJ_GET commands,
from Andrii Nakryiko.
3) Add capability for libbpf to resize datasec maps when backed via mmap,
from JP Kobryn.
4) Move all the test kfuncs for CI out of the kernel and into bpf_testmod,
from Jiri Olsa.
5) Big batch of xsk selftest improvements to prep for multi-buffer testing,
from Magnus Karlsson.
6) Show the target_{obj,btf}_id in tracing link's fdinfo and dump it
via bpftool, from Yafang Shao.
7) Various misc BPF selftest improvements to work with upcoming LLVM 17,
from Yonghong Song.
8) Extend bpftool to specify netdevice for resolving XDP hints,
from Larysa Zaremba.
9) Document masking in shift operations for the insn set document,
from Dave Thaler.
10) Extend BPF selftests to check xdp_feature support for bond driver,
from Lorenzo Bianconi.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (54 commits)
bpf: Fix bad unlock balance on freeze_mutex
libbpf: Ensure FD >= 3 during bpf_map__reuse_fd()
libbpf: Ensure libbpf always opens files with O_CLOEXEC
selftests/bpf: Check whether to run selftest
libbpf: Change var type in datasec resize func
bpf: drop unnecessary bpf_capable() check in BPF_MAP_FREEZE command
libbpf: Selftests for resizing datasec maps
libbpf: Add capability for resizing datasec maps
selftests/bpf: Add path_fd-based BPF_OBJ_PIN and BPF_OBJ_GET tests
libbpf: Add opts-based bpf_obj_pin() API and add support for path_fd
bpf: Support O_PATH FDs in BPF_OBJ_PIN and BPF_OBJ_GET commands
libbpf: Start v1.3 development cycle
bpf: Validate BPF object in BPF_OBJ_PIN before calling LSM
bpftool: Specify XDP Hints ifname when loading program
selftests/bpf: Add xdp_feature selftest for bond device
selftests/bpf: Test bpf_sock_destroy
selftests/bpf: Add helper to get port using getsockname
bpf: Add bpf_sock_destroy kfunc
bpf: Add kfunc filter function to 'struct btf_kfunc_id_set'
bpf: udp: Implement batching for sockets iterator
...
====================
Link: https://lore.kernel.org/r/20230526222747.17775-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Commit c4c84f6fb2 ("bpf: drop unnecessary bpf_capable() check in
BPF_MAP_FREEZE command") moved the permissions check outside of the
freeze_mutex in the map_freeze() handler. The error paths still jumps
to the err_put which tries to unlock the freeze_mutex even though it
was not locked in the first place. Fix it.
Fixes: c4c84f6fb2 ("bpf: drop unnecessary bpf_capable() check in BPF_MAP_FREEZE command")
Reported-by: syzbot+8982e75c2878b9ffeac5@syzkaller.appspotmail.com
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Seems like that extra bpf_capable() check in BPF_MAP_FREEZE handler was
unintentionally left when we switched to a model that all BPF map
operations should be allowed regardless of CAP_BPF (or any other
capabilities), as long as process got BPF map FD somehow.
This patch replaces bpf_capable() check in BPF_MAP_FREEZE handler with
writeable access check, given conceptually freezing the map is modifying
it: map becomes unmodifiable for subsequent updates.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230524225421.1587859-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Current UAPI of BPF_OBJ_PIN and BPF_OBJ_GET commands of bpf() syscall
forces users to specify pinning location as a string-based absolute or
relative (to current working directory) path. This has various
implications related to security (e.g., symlink-based attacks), forces
BPF FS to be exposed in the file system, which can cause races with
other applications.
One of the feedbacks we got from folks working with containers heavily
was that inability to use purely FD-based location specification was an
unfortunate limitation and hindrance for BPF_OBJ_PIN and BPF_OBJ_GET
commands. This patch closes this oversight, adding path_fd field to
BPF_OBJ_PIN and BPF_OBJ_GET UAPI, following conventions established by
*at() syscalls for dirfd + pathname combinations.
This now allows interesting possibilities like working with detached BPF
FS mount (e.g., to perform multiple pinnings without running a risk of
someone interfering with them), and generally making pinning/getting
more secure and not prone to any races and/or security attacks.
This is demonstrated by a selftest added in subsequent patch that takes
advantage of new mount APIs (fsopen, fsconfig, fsmount) to demonstrate
creating detached BPF FS mount, pinning, and then getting BPF map out of
it, all while never exposing this private instance of BPF FS to outside
worlds.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Link: https://lore.kernel.org/bpf/20230523170013.728457-4-andrii@kernel.org
Do a sanity check whether provided file-to-be-pinned is actually a BPF
object (prog, map, btf) before calling security_path_mknod LSM hook. If
it's not, LSM hook doesn't have to be triggered, as the operation has no
chance of succeeding anyways.
Suggested-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Link: https://lore.kernel.org/bpf/20230522232917.2454595-2-andrii@kernel.org
The LRU and LRU_PERCPU maps allocate a new element on update before locking the
target hash table bucket. Right after that the maps try to lock the bucket.
If this fails, then maps return -EBUSY to the caller without releasing the
allocated element. This makes the element untracked: it doesn't belong to
either of free lists, and it doesn't belong to the hash table, so can't be
re-used; this eventually leads to the permanent -ENOMEM on LRU map updates,
which is unexpected. Fix this by returning the element to the local free list
if bucket locking fails.
Fixes: 20b6cc34ea ("bpf: Avoid hashtab deadlock with map_locked")
Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
Link: https://lore.kernel.org/r/20230522154558.2166815-1-aspsk@isovalent.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
This commit adds the ability to filter kfuncs to certain BPF program
types. This is required to limit bpf_sock_destroy kfunc implemented in
follow-up commits to programs with attach type 'BPF_TRACE_ITER'.
The commit adds a callback filter to 'struct btf_kfunc_id_set'. The
filter has access to the `bpf_prog` construct including its properties
such as `expected_attached_type`.
Signed-off-by: Aditi Ghag <aditi.ghag@isovalent.com>
Link: https://lore.kernel.org/r/20230519225157.760788-7-aditi.ghag@isovalent.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
The target_btf_id can help us understand which kernel function is
linked by a tracing prog. The target_btf_id and target_obj_id have
already been exposed to userspace, so we just need to show them.
The result as follows,
$ cat /proc/10673/fdinfo/10
pos: 0
flags: 02000000
mnt_id: 15
ino: 2094
link_type: tracing
link_id: 2
prog_tag: a04f5eef06a7f555
prog_id: 13
attach_type: 24
target_obj_id: 1
target_btf_id: 13964
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230517103126.68372-2-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
A narrow load from a 64-bit context field results in a 64-bit load
followed potentially by a 64-bit right-shift and then a bitwise AND
operation to extract the relevant data.
In the case of a 32-bit access, an immediate mask of 0xffffffff is used
to construct a 64-bit BPP_AND operation which then sign-extends the mask
value and effectively acts as a glorified no-op. For example:
0: 61 10 00 00 00 00 00 00 r0 = *(u32 *)(r1 + 0)
results in the following code generation for a 64-bit field:
ldr x7, [x7] // 64-bit load
mov x10, #0xffffffffffffffff
and x7, x7, x10
Fix the mask generation so that narrow loads always perform a 32-bit AND
operation:
ldr x7, [x7] // 64-bit load
mov w10, #0xffffffff
and w7, w7, w10
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Krzesimir Nowak <krzesimir@kinvolk.io>
Cc: Andrey Ignatov <rdna@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Fixes: 31fd85816d ("bpf: permits narrower load from bpf program context fields")
Signed-off-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20230518102528.1341-1-will@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
It's trivial for user to trigger "verifier log line truncated" warning,
as verifier has a fixed-sized buffer of 1024 bytes (as of now), and there are at
least two pieces of user-provided information that can be output through
this buffer, and both can be arbitrarily sized by user:
- BTF names;
- BTF.ext source code lines strings.
Verifier log buffer should be properly sized for typical verifier state
output. But it's sort-of expected that this buffer won't be long enough
in some circumstances. So let's drop the check. In any case code will
work correctly, at worst truncating a part of a single line output.
Reported-by: syzbot+8b2a08dfbd25fd933d75@syzkaller.appspotmail.com
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230516180409.3549088-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:
====================
pull-request: bpf-next 2023-05-16
We've added 57 non-merge commits during the last 19 day(s) which contain
a total of 63 files changed, 3293 insertions(+), 690 deletions(-).
The main changes are:
1) Add precision propagation to verifier for subprogs and callbacks,
from Andrii Nakryiko.
2) Improve BPF's {g,s}setsockopt() handling with wrong option lengths,
from Stanislav Fomichev.
3) Utilize pahole v1.25 for the kernel's BTF generation to filter out
inconsistent function prototypes, from Alan Maguire.
4) Various dyn-pointer verifier improvements to relax restrictions,
from Daniel Rosenberg.
5) Add a new bpf_task_under_cgroup() kfunc for designated task,
from Feng Zhou.
6) Unblock tests for arm64 BPF CI after ftrace supporting direct call,
from Florent Revest.
7) Add XDP hint kfunc metadata for RX hash/timestamp for igc,
from Jesper Dangaard Brouer.
8) Add several new dyn-pointer kfuncs to ease their usability,
from Joanne Koong.
9) Add in-depth LRU internals description and dot function graph,
from Joe Stringer.
10) Fix KCSAN report on bpf_lru_list when accessing node->ref,
from Martin KaFai Lau.
11) Only dump unprivileged_bpf_disabled log warning upon write,
from Kui-Feng Lee.
12) Extend test_progs to directly passing allow/denylist file,
from Stephen Veiss.
13) Fix BPF trampoline memleak upon failure attaching to fentry,
from Yafang Shao.
14) Fix emitting struct bpf_tcp_sock type in vmlinux BTF,
from Yonghong Song.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (57 commits)
bpf: Fix memleak due to fentry attach failure
bpf: Remove bpf trampoline selector
bpf, arm64: Support struct arguments in the BPF trampoline
bpftool: JIT limited misreported as negative value on aarch64
bpf: fix calculation of subseq_idx during precision backtracking
bpf: Remove anonymous union in bpf_kfunc_call_arg_meta
bpf: Document EFAULT changes for sockopt
selftests/bpf: Correctly handle optlen > 4096
selftests/bpf: Update EFAULT {g,s}etsockopt selftests
bpf: Don't EFAULT for {g,s}setsockopt with wrong optlen
libbpf: fix offsetof() and container_of() to work with CO-RE
bpf: Address KCSAN report on bpf_lru_list
bpf: Add --skip_encoding_btf_inconsistent_proto, --btf_gen_optimized to pahole flags for v1.25
selftests/bpf: Accept mem from dynptr in helper funcs
bpf: verifier: Accept dynptr mem as mem in helpers
selftests/bpf: Check overflow in optional buffer
selftests/bpf: Test allowing NULL buffer in dynptr slice
bpf: Allow NULL buffers in bpf_dynptr_slice(_rw)
selftests/bpf: Add testcase for bpf_task_under_cgroup
bpf: Add bpf_task_under_cgroup() kfunc
...
====================
Link: https://lore.kernel.org/r/20230515225603.27027-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
If it fails to attach fentry, the allocated bpf trampoline image will be
left in the system. That can be verified by checking /proc/kallsyms.
This meamleak can be verified by a simple bpf program as follows:
SEC("fentry/trap_init")
int fentry_run()
{
return 0;
}
It will fail to attach trap_init because this function is freed after
kernel init, and then we can find the trampoline image is left in the
system by checking /proc/kallsyms.
$ tail /proc/kallsyms
ffffffffc0613000 t bpf_trampoline_6442453466_1 [bpf]
ffffffffc06c3000 t bpf_trampoline_6442453466_1 [bpf]
$ bpftool btf dump file /sys/kernel/btf/vmlinux | grep "FUNC 'trap_init'"
[2522] FUNC 'trap_init' type_id=119 linkage=static
$ echo $((6442453466 & 0x7fffffff))
2522
Note that there are two left bpf trampoline images, that is because the
libbpf will fallback to raw tracepoint if -EINVAL is returned.
Fixes: e21aa34178 ("bpf: Fix fexit trampoline.")
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <song@kernel.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Link: https://lore.kernel.org/bpf/20230515130849.57502-2-laoar.shao@gmail.com
After commit e21aa34178 ("bpf: Fix fexit trampoline."), the selector is only
used to indicate how many times the bpf trampoline image are updated and been
displayed in the trampoline ksym name. After the trampoline is freed, the
selector will start from 0 again. So the selector is a useless value to the
user. We can remove it.
If the user want to check whether the bpf trampoline image has been updated
or not, the user can compare the address. Each time the trampoline image is
updated, the address will change consequently. Jiri also pointed out another
issue that perf is still using the old name "bpf_trampoline_%lu", so this
change can fix the issue in perf.
Fixes: e21aa34178 ("bpf: Fix fexit trampoline.")
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <song@kernel.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Link: https://lore.kernel.org/bpf/ZFvOOlrmHiY9AgXE@krava
Link: https://lore.kernel.org/bpf/20230515130849.57502-3-laoar.shao@gmail.com
Subsequent instruction index (subseq_idx) is an index of an instruction
that was verified/executed by verifier after the currently processed
instruction. It is maintained during precision backtracking processing
and is used to detect various subprog calling conditions.
This patch fixes the bug with incorrectly resetting subseq_idx to -1
when going from child state to parent state during backtracking. If we
don't maintain correct subseq_idx we can misidentify subprog calls
leading to precision tracking bugs.
One such case was triggered by test_global_funcs/global_func9 test where
global subprog call happened to be the very last instruction in parent
state, leading to subseq_idx==-1, triggering WARN_ONCE:
[ 36.045754] verifier backtracking bug
[ 36.045764] WARNING: CPU: 13 PID: 2073 at kernel/bpf/verifier.c:3503 __mark_chain_precision+0xcc6/0xde0
[ 36.046819] Modules linked in: aesni_intel(E) crypto_simd(E) cryptd(E) kvm_intel(E) kvm(E) irqbypass(E) i2c_piix4(E) serio_raw(E) i2c_core(E) crc32c_intel)
[ 36.048040] CPU: 13 PID: 2073 Comm: test_progs Tainted: G W OE 6.3.0-07976-g4d585f48ee6b-dirty #972
[ 36.048783] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
[ 36.049648] RIP: 0010:__mark_chain_precision+0xcc6/0xde0
[ 36.050038] Code: 3d 82 c6 05 bb 35 32 02 01 e8 66 21 ec ff 0f 0b b8 f2 ff ff ff e9 30 f5 ff ff 48 c7 c7 f3 61 3d 82 4c 89 0c 24 e8 4a 21 ec ff <0f> 0b 4c0
With the fix precision tracking across multiple states works correctly now:
mark_precise: frame0: last_idx 45 first_idx 38 subseq_idx -1
mark_precise: frame0: regs=r8 stack= before 44: (61) r7 = *(u32 *)(r10 -4)
mark_precise: frame0: regs=r8 stack= before 43: (85) call pc+41
mark_precise: frame0: regs=r8 stack= before 42: (07) r1 += -48
mark_precise: frame0: regs=r8 stack= before 41: (bf) r1 = r10
mark_precise: frame0: regs=r8 stack= before 40: (63) *(u32 *)(r10 -48) = r1
mark_precise: frame0: regs=r8 stack= before 39: (b4) w1 = 0
mark_precise: frame0: regs=r8 stack= before 38: (85) call pc+38
mark_precise: frame0: parent state regs=r8 stack=: R0_w=scalar() R1_w=map_value(off=4,ks=4,vs=8,imm=0) R6=1 R7_w=scalar() R8_r=P0 R10=fpm
mark_precise: frame0: last_idx 36 first_idx 28 subseq_idx 38
mark_precise: frame0: regs=r8 stack= before 36: (18) r1 = 0xffff888104f2ed14
mark_precise: frame0: regs=r8 stack= before 35: (85) call pc+33
mark_precise: frame0: regs=r8 stack= before 33: (18) r1 = 0xffff888104f2ed10
mark_precise: frame0: regs=r8 stack= before 32: (85) call pc+36
mark_precise: frame0: regs=r8 stack= before 31: (07) r1 += -4
mark_precise: frame0: regs=r8 stack= before 30: (bf) r1 = r10
mark_precise: frame0: regs=r8 stack= before 29: (63) *(u32 *)(r10 -4) = r7
mark_precise: frame0: regs=r8 stack= before 28: (4c) w7 |= w0
mark_precise: frame0: parent state regs=r8 stack=: R0_rw=scalar() R6=1 R7_rw=scalar() R8_rw=P0 R10=fp0 fp-48_r=mmmmmmmm
mark_precise: frame0: last_idx 27 first_idx 16 subseq_idx 28
mark_precise: frame0: regs=r8 stack= before 27: (85) call pc+31
mark_precise: frame0: regs=r8 stack= before 26: (b7) r1 = 0
mark_precise: frame0: regs=r8 stack= before 25: (b7) r8 = 0
Note how subseq_idx starts out as -1, then is preserved as 38 and then 28 as we
go up the parent state chain.
Reported-by: Alexei Starovoitov <ast@kernel.org>
Fixes: fde2a3882b ("bpf: support precision propagation in the presence of subprogs")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230515180710.1535018-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
For kfuncs like bpf_obj_drop and bpf_refcount_acquire - which take
user-defined types as input - the verifier needs to track the specific
type passed in when checking a particular kfunc call. This requires
tracking (btf, btf_id) tuple. In commit 7c50b1cb76
("bpf: Add bpf_refcount_acquire kfunc") I added an anonymous union with
inner structs named after the specific kfuncs tracking this information,
with the goal of making it more obvious which kfunc this data was being
tracked / expected to be tracked on behalf of.
In a recent series adding a new user of this tuple, Alexei mentioned
that he didn't like this union usage as it doesn't really help with
readability or bug-proofing ([0]). In an offline convo we agreed to
have the tuple be fields (arg_btf, arg_btf_id), with comments in
bpf_kfunc_call_arg_meta definition enumerating the uses of the fields by
kfunc-specific handling logic. Such a pattern is used by struct
bpf_reg_state without trouble.
Accordingly, this patch removes the anonymous union in favor of arg_btf
and arg_btf_id fields and comment enumerating their current uses. The
patch also removes struct btf_and_id, which was only being used by the
removed union's inner structs.
This is a mechanical change, existing linked_list and rbtree tests will
validate that correct (btf, btf_id) are being passed.
[0]: https://lore.kernel.org/bpf/20230505021707.vlyiwy57vwxglbka@dhcp-172-26-102-232.dhcp.thefacebook.com
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230510213047.1633612-1-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
With the way the hooks implemented right now, we have a special
condition: optval larger than PAGE_SIZE will expose only first 4k into
BPF; any modifications to the optval are ignored. If the BPF program
doesn't handle this condition by resetting optlen to 0,
the userspace will get EFAULT.
The intention of the EFAULT was to make it apparent to the
developers that the program is doing something wrong.
However, this inadvertently might affect production workloads
with the BPF programs that are not too careful (i.e., returning EFAULT
for perfectly valid setsockopt/getsockopt calls).
Let's try to minimize the chance of BPF program screwing up userspace
by ignoring the output of those BPF programs (instead of returning
EFAULT to the userspace). pr_info_once those cases to
the dmesg to help with figuring out what's going wrong.
Fixes: 0d01da6afc ("bpf: implement getsockopt and setsockopt hooks")
Suggested-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230511170456.1759459-2-sdf@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
KCSAN reported a data-race when accessing node->ref.
Although node->ref does not have to be accurate,
take this chance to use a more common READ_ONCE() and WRITE_ONCE()
pattern instead of data_race().
There is an existing bpf_lru_node_is_ref() and bpf_lru_node_set_ref().
This patch also adds bpf_lru_node_clear_ref() to do the
WRITE_ONCE(node->ref, 0) also.
==================================================================
BUG: KCSAN: data-race in __bpf_lru_list_rotate / __htab_lru_percpu_map_update_elem
write to 0xffff888137038deb of 1 bytes by task 11240 on cpu 1:
__bpf_lru_node_move kernel/bpf/bpf_lru_list.c:113 [inline]
__bpf_lru_list_rotate_active kernel/bpf/bpf_lru_list.c:149 [inline]
__bpf_lru_list_rotate+0x1bf/0x750 kernel/bpf/bpf_lru_list.c:240
bpf_lru_list_pop_free_to_local kernel/bpf/bpf_lru_list.c:329 [inline]
bpf_common_lru_pop_free kernel/bpf/bpf_lru_list.c:447 [inline]
bpf_lru_pop_free+0x638/0xe20 kernel/bpf/bpf_lru_list.c:499
prealloc_lru_pop kernel/bpf/hashtab.c:290 [inline]
__htab_lru_percpu_map_update_elem+0xe7/0x820 kernel/bpf/hashtab.c:1316
bpf_percpu_hash_update+0x5e/0x90 kernel/bpf/hashtab.c:2313
bpf_map_update_value+0x2a9/0x370 kernel/bpf/syscall.c:200
generic_map_update_batch+0x3ae/0x4f0 kernel/bpf/syscall.c:1687
bpf_map_do_batch+0x2d9/0x3d0 kernel/bpf/syscall.c:4534
__sys_bpf+0x338/0x810
__do_sys_bpf kernel/bpf/syscall.c:5096 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5094 [inline]
__x64_sys_bpf+0x43/0x50 kernel/bpf/syscall.c:5094
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
read to 0xffff888137038deb of 1 bytes by task 11241 on cpu 0:
bpf_lru_node_set_ref kernel/bpf/bpf_lru_list.h:70 [inline]
__htab_lru_percpu_map_update_elem+0x2f1/0x820 kernel/bpf/hashtab.c:1332
bpf_percpu_hash_update+0x5e/0x90 kernel/bpf/hashtab.c:2313
bpf_map_update_value+0x2a9/0x370 kernel/bpf/syscall.c:200
generic_map_update_batch+0x3ae/0x4f0 kernel/bpf/syscall.c:1687
bpf_map_do_batch+0x2d9/0x3d0 kernel/bpf/syscall.c:4534
__sys_bpf+0x338/0x810
__do_sys_bpf kernel/bpf/syscall.c:5096 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5094 [inline]
__x64_sys_bpf+0x43/0x50 kernel/bpf/syscall.c:5094
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
value changed: 0x01 -> 0x00
Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 11241 Comm: syz-executor.3 Not tainted 6.3.0-rc7-syzkaller-00136-g6a66fdd29ea1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023
==================================================================
Reported-by: syzbot+ebe648a84e8784763f82@syzkaller.appspotmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20230511043748.1384166-1-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This allows using memory retrieved from dynptrs with helper functions
that accept ARG_PTR_TO_MEM. For instance, results from bpf_dynptr_data
can be passed along to bpf_strncmp.
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Link: https://lore.kernel.org/r/20230506013134.2492210-5-drosen@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
bpf_dynptr_slice(_rw) uses a user provided buffer if it can not provide
a pointer to a block of contiguous memory. This buffer is unused in the
case of local dynptrs, and may be unused in other cases as well. There
is no need to require the buffer, as the kfunc can just return NULL if
it was needed and not provided.
This adds another kfunc annotation, __opt, which combines with __sz and
__szk to allow the buffer associated with the size to be NULL. If the
buffer is NULL, the verifier does not check that the buffer is of
sufficient size.
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Link: https://lore.kernel.org/r/20230506013134.2492210-2-drosen@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add a kfunc that's similar to the bpf_current_task_under_cgroup.
The difference is that it is a designated task.
When hook sched related functions, sometimes it is necessary to
specify a task instead of the current task.
Signed-off-by: Feng Zhou <zhoufeng.zf@bytedance.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20230506031545.35991-2-zhoufeng.zf@bytedance.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add support precision backtracking in the presence of subprogram frames in
jump history.
This means supporting a few different kinds of subprogram invocation
situations, all requiring a slightly different handling in precision
backtracking handling logic:
- static subprogram calls;
- global subprogram calls;
- callback-calling helpers/kfuncs.
For each of those we need to handle a few precision propagation cases:
- what to do with precision of subprog returns (r0);
- what to do with precision of input arguments;
- for all of them callee-saved registers in caller function should be
propagated ignoring subprog/callback part of jump history.
N.B. Async callback-calling helpers (currently only
bpf_timer_set_callback()) are transparent to all this because they set
a separate async callback environment and thus callback's history is not
shared with main program's history. So as far as all the changes in this
commit goes, such helper is just a regular helper.
Let's look at all these situation in more details. Let's start with
static subprogram being called, using an exxerpt of a simple main
program and its static subprog, indenting subprog's frame slightly to
make everything clear.
frame 0 frame 1 precision set
======= ======= =============
9: r6 = 456;
10: r1 = 123; fr0: r6
11: call pc+10; fr0: r1, r6
22: r0 = r1; fr0: r6; fr1: r1
23: exit fr0: r6; fr1: r0
12: r1 = <map_pointer> fr0: r0, r6
13: r1 += r0; fr0: r0, r6
14: r1 += r6; fr0: r6
15: exit
As can be seen above main function is passing 123 as single argument to
an identity (`return x;`) subprog. Returned value is used to adjust map
pointer offset, which forces r0 to be marked as precise. Then
instruction #14 does the same for callee-saved r6, which will have to be
backtracked all the way to instruction #9. For brevity, precision sets
for instruction #13 and #14 are combined in the diagram above.
First, for subprog calls, r0 returned from subprog (in frame 0) has to
go into subprog's frame 1, and should be cleared from frame 0. So we go
back into subprog's frame knowing we need to mark r0 precise. We then
see that insn #22 sets r0 from r1, so now we care about marking r1
precise. When we pop up from subprog's frame back into caller at
insn #11 we keep r1, as it's an argument-passing register, so we eventually
find `10: r1 = 123;` and satify precision propagation chain for insn #13.
This example demonstrates two sets of rules:
- r0 returned after subprog call has to be moved into subprog's r0 set;
- *static* subprog arguments (r1-r5) are moved back to caller precision set.
Let's look at what happens with callee-saved precision propagation. Insn #14
mark r6 as precise. When we get into subprog's frame, we keep r6 in
frame 0's precision set *only*. Subprog itself has its own set of
independent r6-r10 registers and is not affected. When we eventually
made our way out of subprog frame we keep r6 in precision set until we
reach `9: r6 = 456;`, satisfying propagation. r6-r10 propagation is
perhaps the simplest aspect, it always stays in its original frame.
That's pretty much all we have to do to support precision propagation
across *static subprog* invocation.
Let's look at what happens when we have global subprog invocation.
frame 0 frame 1 precision set
======= ======= =============
9: r6 = 456;
10: r1 = 123; fr0: r6
11: call pc+10; # global subprog fr0: r6
12: r1 = <map_pointer> fr0: r0, r6
13: r1 += r0; fr0: r0, r6
14: r1 += r6; fr0: r6;
15: exit
Starting from insn #13, r0 has to be precise. We backtrack all the way
to insn #11 (call pc+10) and see that subprog is global, so was already
validated in isolation. As opposed to static subprog, global subprog
always returns unknown scalar r0, so that satisfies precision
propagation and we drop r0 from precision set. We are done for insns #13.
Now for insn #14. r6 is in precision set, we backtrack to `call pc+10;`.
Here we need to recognize that this is effectively both exit and entry
to global subprog, which means we stay in caller's frame. So we carry on
with r6 still in precision set, until we satisfy it at insn #9. The only
hard part with global subprogs is just knowing when it's a global func.
Lastly, callback-calling helpers and kfuncs do simulate subprog calls,
so jump history will have subprog instructions in between caller
program's instructions, but the rules of propagating r0 and r1-r5
differ, because we don't actually directly call callback. We actually
call helper/kfunc, which at runtime will call subprog, so the only
difference between normal helper/kfunc handling is that we need to make
sure to skip callback simulatinog part of jump history.
Let's look at an example to make this clearer.
frame 0 frame 1 precision set
======= ======= =============
8: r6 = 456;
9: r1 = 123; fr0: r6
10: r2 = &callback; fr0: r6
11: call bpf_loop; fr0: r6
22: r0 = r1; fr0: r6 fr1:
23: exit fr0: r6 fr1:
12: r1 = <map_pointer> fr0: r0, r6
13: r1 += r0; fr0: r0, r6
14: r1 += r6; fr0: r6;
15: exit
Again, insn #13 forces r0 to be precise. As soon as we get to `23: exit`
we see that this isn't actually a static subprog call (it's `call
bpf_loop;` helper call instead). So we clear r0 from precision set.
For callee-saved register, there is no difference: it stays in frame 0's
precision set, we go through insn #22 and #23, ignoring them until we
get back to caller frame 0, eventually satisfying precision backtrack
logic at insn #8 (`r6 = 456;`).
Assuming callback needed to set r0 as precise at insn #23, we'd
backtrack to insn #22, switching from r0 to r1, and then at the point
when we pop back to frame 0 at insn #11, we'll clear r1-r5 from
precision set, as we don't really do a subprog call directly, so there
is no input argument precision propagation.
That's pretty much it. With these changes, it seems like the only still
unsupported situation for precision backpropagation is the case when
program is accessing stack through registers other than r10. This is
still left as unsupported (though rare) case for now.
As for results. For selftests, few positive changes for bigger programs,
cls_redirect in dynptr variant benefitting the most:
[vmuser@archvm bpf]$ ./veristat -C ~/subprog-precise-before-results.csv ~/subprog-precise-after-results.csv -f @veristat.cfg -e file,prog,insns -f 'insns_diff!=0'
File Program Insns (A) Insns (B) Insns (DIFF)
---------------------------------------- ------------- --------- --------- ----------------
pyperf600_bpf_loop.bpf.linked1.o on_event 2060 2002 -58 (-2.82%)
test_cls_redirect_dynptr.bpf.linked1.o cls_redirect 15660 2914 -12746 (-81.39%)
test_cls_redirect_subprogs.bpf.linked1.o cls_redirect 61620 59088 -2532 (-4.11%)
xdp_synproxy_kern.bpf.linked1.o syncookie_tc 109980 86278 -23702 (-21.55%)
xdp_synproxy_kern.bpf.linked1.o syncookie_xdp 97716 85147 -12569 (-12.86%)
Cilium progress don't really regress. They don't use subprogs and are
mostly unaffected, but some other fixes and improvements could have
changed something. This doesn't appear to be the case:
[vmuser@archvm bpf]$ ./veristat -C ~/subprog-precise-before-results-cilium.csv ~/subprog-precise-after-results-cilium.csv -e file,prog,insns -f 'insns_diff!=0'
File Program Insns (A) Insns (B) Insns (DIFF)
------------- ------------------------------ --------- --------- ------------
bpf_host.o tail_nodeport_nat_ingress_ipv6 4983 5003 +20 (+0.40%)
bpf_lxc.o tail_nodeport_nat_ingress_ipv6 4983 5003 +20 (+0.40%)
bpf_overlay.o tail_nodeport_nat_ingress_ipv6 4983 5003 +20 (+0.40%)
bpf_xdp.o tail_handle_nat_fwd_ipv6 12475 12504 +29 (+0.23%)
bpf_xdp.o tail_nodeport_nat_ingress_ipv6 6363 6371 +8 (+0.13%)
Looking at (somewhat anonymized) Meta production programs, we see mostly
insignificant variation in number of instructions, with one program
(syar_bind6_protect6) benefitting the most at -17%.
[vmuser@archvm bpf]$ ./veristat -C ~/subprog-precise-before-results-fbcode.csv ~/subprog-precise-after-results-fbcode.csv -e prog,insns -f 'insns_diff!=0'
Program Insns (A) Insns (B) Insns (DIFF)
------------------------ --------- --------- ----------------
on_request_context_event 597 585 -12 (-2.01%)
read_async_py_stack 43789 43657 -132 (-0.30%)
read_sync_py_stack 35041 37599 +2558 (+7.30%)
rrm_usdt 946 940 -6 (-0.63%)
sysarmor_inet6_bind 28863 28249 -614 (-2.13%)
sysarmor_inet_bind 28845 28240 -605 (-2.10%)
syar_bind4_protect4 154145 147640 -6505 (-4.22%)
syar_bind6_protect6 165242 137088 -28154 (-17.04%)
syar_task_exit_setgid 21289 19720 -1569 (-7.37%)
syar_task_exit_setuid 21290 19721 -1569 (-7.37%)
do_uprobe 19967 19413 -554 (-2.77%)
tw_twfw_ingress 215877 204833 -11044 (-5.12%)
tw_twfw_tc_in 215877 204833 -11044 (-5.12%)
But checking duration (wall clock) differences, that is the actual time taken
by verifier to validate programs, we see a sometimes dramatic improvements, all
the way to about 16x improvements:
[vmuser@archvm bpf]$ ./veristat -C ~/subprog-precise-before-results-meta.csv ~/subprog-precise-after-results-meta.csv -e prog,duration -s duration_diff^ | head -n20
Program Duration (us) (A) Duration (us) (B) Duration (us) (DIFF)
---------------------------------------- ----------------- ----------------- --------------------
tw_twfw_ingress 4488374 272836 -4215538 (-93.92%)
tw_twfw_tc_in 4339111 268175 -4070936 (-93.82%)
tw_twfw_egress 3521816 270751 -3251065 (-92.31%)
tw_twfw_tc_eg 3472878 284294 -3188584 (-91.81%)
balancer_ingress 343119 291391 -51728 (-15.08%)
syar_bind6_protect6 78992 64782 -14210 (-17.99%)
ttls_tc_ingress 11739 8176 -3563 (-30.35%)
kprobe__security_inode_link 13864 11341 -2523 (-18.20%)
read_sync_py_stack 21927 19442 -2485 (-11.33%)
read_async_py_stack 30444 28136 -2308 (-7.58%)
syar_task_exit_setuid 10256 8440 -1816 (-17.71%)
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230505043317.3629845-9-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When precision backtracking bails out due to some unsupported sequence
of instructions (e.g., stack access through register other than r10), we
need to mark all SCALAR registers as precise to be safe. Currently,
though, we mark SCALARs precise only starting from the state we detected
unsupported condition, which could be one of the parent states of the
actual current state. This will leave some registers potentially not
marked as precise, even though they should. So make sure we start
marking scalars as precise from current state (env->cur_state).
Further, we don't currently detect a situation when we end up with some
stack slots marked as needing precision, but we ran out of available
states to find the instructions that populate those stack slots. This is
akin the `i >= func->allocated_stack / BPF_REG_SIZE` check and should be
handled similarly by falling back to marking all SCALARs precise. Add
this check when we run out of states.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230505043317.3629845-8-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Fix propagate_precision() logic to perform propagation of all necessary
registers and stack slots across all active frames *in one batch step*.
Doing this for each register/slot in each individual frame is wasteful,
but the main problem is that backtracking of instruction in any frame
except the deepest one just doesn't work. This is due to backtracking
logic relying on jump history, and available jump history always starts
(or ends, depending how you view it) in current frame. So, if
prog A (frame #0) called subprog B (frame #1) and we need to propagate
precision of, say, register R6 (callee-saved) within frame #0, we
actually don't even know where jump history that corresponds to prog
A even starts. We'd need to skip subprog part of jump history first to
be able to do this.
Luckily, with struct backtrack_state and __mark_chain_precision()
handling bitmasks tracking/propagation across all active frames at the
same time (added in previous patch), propagate_precision() can be both
fixed and sped up by setting all the necessary bits across all frames
and then performing one __mark_chain_precision() pass. This makes it
unnecessary to skip subprog parts of jump history.
We also improve logging along the way, to clearly specify which
registers' and slots' precision markings are propagated within which
frame. Each frame will have dedicated line and all registers and stack
slots from that frame will be reported in format similar to precision
backtrack regs/stack logging. E.g.:
frame 1: propagating r1,r2,r3,fp-8,fp-16
frame 0: propagating r3,r9,fp-120
Fixes: 529409ea92 ("bpf: propagate precision across all frames, not just the last one")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230505043317.3629845-7-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Teach __mark_chain_precision logic to maintain register/stack masks
across all active frames when going from child state to parent state.
Currently this should be mostly no-op, as precision backtracking usually
bails out when encountering subprog entry/exit.
It's not very apparent from the diff due to increased indentation, but
the logic remains the same, except everything is done on specific `fr`
frame index. Calls to bt_clear_reg() and bt_clear_slot() are replaced
with frame-specific bt_clear_frame_reg() and bt_clear_frame_slot(),
where frame index is passed explicitly, instead of using current frame
number.
We also adjust logging to emit affected frame number. And we also add
better logging of human-readable register and stack slot masks, similar
to previous patch.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230505043317.3629845-6-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add helper to format register and stack masks in more human-readable
format. Adjust logging a bit during backtrack propagation and especially
during forcing precision fallback logic to make it clearer what's going
on (with log_level=2, of course), and also start reporting affected
frame depth. This is in preparation for having more than one active
frame later when precision propagation between subprog calls is added.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230505043317.3629845-5-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add struct backtrack_state and straightforward API around it to keep
track of register and stack masks used and maintained during precision
backtracking process. Having this logic separately allow to keep
high-level backtracking algorithm cleaner, but also it sets us up to
cleanly keep track of register and stack masks per frame, allowing (with
some further logic adjustments) to perform precision backpropagation
across multiple frames (i.e., subprog calls).
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230505043317.3629845-4-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When handling instructions that read register slots, mark relevant stack
slots as scratched so that verifier log would contain those slots' states, in
addition to currently emitted registers with stack slot offsets.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230505043317.3629845-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Only print the warning message if you are writing to
"/proc/sys/kernel/unprivileged_bpf_disabled".
The kernel may print an annoying warning when you read
"/proc/sys/kernel/unprivileged_bpf_disabled" saying
WARNING: Unprivileged eBPF is enabled with eIBRS on, data leaks possible
via Spectre v2 BHB attacks!
However, this message is only meaningful when the feature is
disabled or enabled.
Signed-off-by: Kui-Feng Lee <kuifeng@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20230502181418.308479-1-kuifeng@meta.com
* cpuset changes including the fix for an incorrect interaction with CPU
hotplug and an optimization.
* Other doc and cosmetic changes.
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Merge tag 'cgroup-for-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo:
- cpuset changes including the fix for an incorrect interaction with
CPU hotplug and an optimization
- Other doc and cosmetic changes
* tag 'cgroup-for-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
docs: cgroup-v1/cpusets: update libcgroup project link
cgroup/cpuset: Minor updates to test_cpuset_prs.sh
cgroup/cpuset: Include offline CPUs when tasks' cpumasks in top_cpuset are updated
cgroup/cpuset: Skip task update if hotplug doesn't affect current cpuset
cpuset: Clean up cpuset_node_allowed
cgroup: bpf: use cgroup_lock()/cgroup_unlock() wrappers
The cloned dynptr will point to the same data as its parent dynptr,
with the same type, offset, size and read-only properties.
Any writes to a dynptr will be reflected across all instances
(by 'instance', this means any dynptrs that point to the same
underlying data).
Please note that data slice and dynptr invalidations will affect all
instances as well. For example, if bpf_dynptr_write() is called on an
skb-type dynptr, all data slices of dynptr instances to that skb
will be invalidated as well (eg data slices of any clones, parents,
grandparents, ...). Another example is if a ringbuf dynptr is submitted,
any instance of that dynptr will be invalidated.
Changing the view of the dynptr (eg advancing the offset or
trimming the size) will only affect that dynptr and not affect any
other instances.
One example use case where cloning may be helpful is for hashing or
iterating through dynptr data. Cloning will allow the user to maintain
the original view of the dynptr for future use, while also allowing
views to smaller subsets of the data after the offset is advanced or the
size is trimmed.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20230420071414.570108-5-joannelkoong@gmail.com
bpf_dynptr_size returns the number of usable bytes in a dynptr.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20230420071414.570108-4-joannelkoong@gmail.com
bpf_dynptr_is_null returns true if the dynptr is null / invalid
(determined by whether ptr->data is NULL), else false if
the dynptr is a valid dynptr.
bpf_dynptr_is_rdonly returns true if the dynptr is read-only,
else false if the dynptr is read-writable. If the dynptr is
null / invalid, false is returned by default.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20230420071414.570108-3-joannelkoong@gmail.com
Add a new kfunc
int bpf_dynptr_adjust(struct bpf_dynptr_kern *ptr, u32 start, u32 end);
which adjusts the dynptr to reflect the new [start, end) interval.
In particular, it advances the offset of the dynptr by "start" bytes,
and if end is less than the size of the dynptr, then this will trim the
dynptr accordingly.
Adjusting the dynptr interval may be useful in certain situations.
For example, when hashing which takes in generic dynptrs, if the dynptr
points to a struct but only a certain memory region inside the struct
should be hashed, adjust can be used to narrow in on the
specific region to hash.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20230420071414.570108-2-joannelkoong@gmail.com
Core
----
- Introduce a config option to tweak MAX_SKB_FRAGS. Increasing the
default value allows for better BIG TCP performances.
- Reduce compound page head access for zero-copy data transfers.
- RPS/RFS improvements, avoiding unneeded NET_RX_SOFTIRQ when possible.
- Threaded NAPI improvements, adding defer skb free support and unneeded
softirq avoidance.
- Address dst_entry reference count scalability issues, via false
sharing avoidance and optimize refcount tracking.
- Add lockless accesses annotation to sk_err[_soft].
- Optimize again the skb struct layout.
- Extends the skb drop reasons to make it usable by multiple
subsystems.
- Better const qualifier awareness for socket casts.
BPF
---
- Add skb and XDP typed dynptrs which allow BPF programs for more
ergonomic and less brittle iteration through data and variable-sized
accesses.
- Add a new BPF netfilter program type and minimal support to hook
BPF programs to netfilter hooks such as prerouting or forward.
- Add more precise memory usage reporting for all BPF map types.
- Adds support for using {FOU,GUE} encap with an ipip device operating
in collect_md mode and add a set of BPF kfuncs for controlling encap
params.
- Allow BPF programs to detect at load time whether a particular kfunc
exists or not, and also add support for this in light skeleton.
- Bigger batch of BPF verifier improvements to prepare for upcoming BPF
open-coded iterators allowing for less restrictive looping capabilities.
- Rework RCU enforcement in the verifier, add kptr_rcu and enforce BPF
programs to NULL-check before passing such pointers into kfunc.
- Add support for kptrs in percpu hashmaps, percpu LRU hashmaps and in
local storage maps.
- Enable RCU semantics for task BPF kptrs and allow referenced kptr
tasks to be stored in BPF maps.
- Add support for refcounted local kptrs to the verifier for allowing
shared ownership, useful for adding a node to both the BPF list and
rbtree.
- Add BPF verifier support for ST instructions in convert_ctx_access()
which will help new -mcpu=v4 clang flag to start emitting them.
- Add ARM32 USDT support to libbpf.
- Improve bpftool's visual program dump which produces the control
flow graph in a DOT format by adding C source inline annotations.
Protocols
---------
- IPv4: Allow adding to IPv4 address a 'protocol' tag. Such value
indicates the provenance of the IP address.
- IPv6: optimize route lookup, dropping unneeded R/W lock acquisition.
- Add the handshake upcall mechanism, allowing the user-space
to implement generic TLS handshake on kernel's behalf.
- Bridge: support per-{Port, VLAN} neighbor suppression, increasing
resilience to nodes failures.
- SCTP: add support for Fair Capacity and Weighted Fair Queueing
schedulers.
- MPTCP: delay first subflow allocation up to its first usage. This
will allow for later better LSM interaction.
- xfrm: Remove inner/outer modes from input/output path. These are
not needed anymore.
- WiFi:
- reduced neighbor report (RNR) handling for AP mode
- HW timestamping support
- support for randomized auth/deauth TA for PASN privacy
- per-link debugfs for multi-link
- TC offload support for mac80211 drivers
- mac80211 mesh fast-xmit and fast-rx support
- enable Wi-Fi 7 (EHT) mesh support
Netfilter
---------
- Add nf_tables 'brouting' support, to force a packet to be routed
instead of being bridged.
- Update bridge netfilter and ovs conntrack helpers to handle
IPv6 Jumbo packets properly, i.e. fetch the packet length
from hop-by-hop extension header. This is needed for BIT TCP
support.
- The iptables 32bit compat interface isn't compiled in by default
anymore.
- Move ip(6)tables builtin icmp matches to the udptcp one.
This has the advantage that icmp/icmpv6 match doesn't load the
iptables/ip6tables modules anymore when iptables-nft is used.
- Extended netlink error report for netdevice in flowtables and
netdev/chains. Allow for incrementally add/delete devices to netdev
basechain. Allow to create netdev chain without device.
Driver API
----------
- Remove redundant Device Control Error Reporting Enable, as PCI core
has already error reporting enabled at enumeration time.
- Move Multicast DB netlink handlers to core, allowing devices other
then bridge to use them.
- Allow the page_pool to directly recycle the pages from safely
localized NAPI.
- Implement lockless TX queue stop/wake combo macros, allowing for
further code de-duplication and sanitization.
- Add YNL support for user headers and struct attrs.
- Add partial YNL specification for devlink.
- Add partial YNL specification for ethtool.
- Add tc-mqprio and tc-taprio support for preemptible traffic classes.
- Add tx push buf len param to ethtool, specifies the maximum number
of bytes of a transmitted packet a driver can push directly to the
underlying device.
- Add basic LED support for switch/phy.
- Add NAPI documentation, stop relaying on external links.
- Convert dsa_master_ioctl() to netdev notifier. This is a preparatory
work to make the hardware timestamping layer selectable by user
space.
- Add transceiver support and improve the error messages for CAN-FD
controllers.
New hardware / drivers
----------------------
- Ethernet:
- AMD/Pensando core device support
- MediaTek MT7981 SoC
- MediaTek MT7988 SoC
- Broadcom BCM53134 embedded switch
- Texas Instruments CPSW9G ethernet switch
- Qualcomm EMAC3 DWMAC ethernet
- StarFive JH7110 SoC
- NXP CBTX ethernet PHY
- WiFi:
- Apple M1 Pro/Max devices
- RealTek rtl8710bu/rtl8188gu
- RealTek rtl8822bs, rtl8822cs and rtl8821cs SDIO chipset
- Bluetooth:
- Realtek RTL8821CS, RTL8851B, RTL8852BS
- Mediatek MT7663, MT7922
- NXP w8997
- Actions Semi ATS2851
- QTI WCN6855
- Marvell 88W8997
- Can:
- STMicroelectronics bxcan stm32f429
Drivers
-------
- Ethernet NICs:
- Intel (1G, icg):
- add tracking and reporting of QBV config errors.
- add support for configuring max SDU for each Tx queue.
- Intel (100G, ice):
- refactor mailbox overflow detection to support Scalable IOV
- GNSS interface optimization
- Intel (i40e):
- support XDP multi-buffer
- nVidia/Mellanox:
- add the support for linux bridge multicast offload
- enable TC offload for egress and engress MACVLAN over bond
- add support for VxLAN GBP encap/decap flows offload
- extend packet offload to fully support libreswan
- support tunnel mode in mlx5 IPsec packet offload
- extend XDP multi-buffer support
- support MACsec VLAN offload
- add support for dynamic msix vectors allocation
- drop RX page_cache and fully use page_pool
- implement thermal zone to report NIC temperature
- Netronome/Corigine:
- add support for multi-zone conntrack offload
- Solarflare/Xilinx:
- support offloading TC VLAN push/pop actions to the MAE
- support TC decap rules
- support unicast PTP
- Other NICs:
- Broadcom (bnxt): enforce software based freq adjustments only
on shared PHC NIC
- RealTek (r8169): refactor to addess ASPM issues during NAPI poll.
- Micrel (lan8841): add support for PTP_PF_PEROUT
- Cadence (macb): enable PTP unicast
- Engleder (tsnep): add XDP socket zero-copy support
- virtio-net: implement exact header length guest feature
- veth: add page_pool support for page recycling
- vxlan: add MDB data path support
- gve: add XDP support for GQI-QPL format
- geneve: accept every ethertype
- macvlan: allow some packets to bypass broadcast queue
- mana: add support for jumbo frame
- Ethernet high-speed switches:
- Microchip (sparx5): Add support for TC flower templates.
- Ethernet embedded switches:
- Broadcom (b54):
- configure 6318 and 63268 RGMII ports
- Marvell (mv88e6xxx):
- faster C45 bus scan
- Microchip:
- lan966x:
- add support for IS1 VCAP
- better TX/RX from/to CPU performances
- ksz9477: add ETS Qdisc support
- ksz8: enhance static MAC table operations and error handling
- sama7g5: add PTP capability
- NXP (ocelot):
- add support for external ports
- add support for preemptible traffic classes
- Texas Instruments:
- add CPSWxG SGMII support for J7200 and J721E
- Intel WiFi (iwlwifi):
- preparation for Wi-Fi 7 EHT and multi-link support
- EHT (Wi-Fi 7) sniffer support
- hardware timestamping support for some devices/firwmares
- TX beacon protection on newer hardware
- Qualcomm 802.11ax WiFi (ath11k):
- MU-MIMO parameters support
- ack signal support for management packets
- RealTek WiFi (rtw88):
- SDIO bus support
- better support for some SDIO devices
(e.g. MAC address from efuse)
- RealTek WiFi (rtw89):
- HW scan support for 8852b
- better support for 6 GHz scanning
- support for various newer firmware APIs
- framework firmware backwards compatibility
- MediaTek WiFi (mt76):
- P2P support
- mesh A-MSDU support
- EHT (Wi-Fi 7) support
- coredump support
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Merge tag 'net-next-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
Pull networking updates from Paolo Abeni:
"Core:
- Introduce a config option to tweak MAX_SKB_FRAGS. Increasing the
default value allows for better BIG TCP performances
- Reduce compound page head access for zero-copy data transfers
- RPS/RFS improvements, avoiding unneeded NET_RX_SOFTIRQ when
possible
- Threaded NAPI improvements, adding defer skb free support and
unneeded softirq avoidance
- Address dst_entry reference count scalability issues, via false
sharing avoidance and optimize refcount tracking
- Add lockless accesses annotation to sk_err[_soft]
- Optimize again the skb struct layout
- Extends the skb drop reasons to make it usable by multiple
subsystems
- Better const qualifier awareness for socket casts
BPF:
- Add skb and XDP typed dynptrs which allow BPF programs for more
ergonomic and less brittle iteration through data and
variable-sized accesses
- Add a new BPF netfilter program type and minimal support to hook
BPF programs to netfilter hooks such as prerouting or forward
- Add more precise memory usage reporting for all BPF map types
- Adds support for using {FOU,GUE} encap with an ipip device
operating in collect_md mode and add a set of BPF kfuncs for
controlling encap params
- Allow BPF programs to detect at load time whether a particular
kfunc exists or not, and also add support for this in light
skeleton
- Bigger batch of BPF verifier improvements to prepare for upcoming
BPF open-coded iterators allowing for less restrictive looping
capabilities
- Rework RCU enforcement in the verifier, add kptr_rcu and enforce
BPF programs to NULL-check before passing such pointers into kfunc
- Add support for kptrs in percpu hashmaps, percpu LRU hashmaps and
in local storage maps
- Enable RCU semantics for task BPF kptrs and allow referenced kptr
tasks to be stored in BPF maps
- Add support for refcounted local kptrs to the verifier for allowing
shared ownership, useful for adding a node to both the BPF list and
rbtree
- Add BPF verifier support for ST instructions in
convert_ctx_access() which will help new -mcpu=v4 clang flag to
start emitting them
- Add ARM32 USDT support to libbpf
- Improve bpftool's visual program dump which produces the control
flow graph in a DOT format by adding C source inline annotations
Protocols:
- IPv4: Allow adding to IPv4 address a 'protocol' tag. Such value
indicates the provenance of the IP address
- IPv6: optimize route lookup, dropping unneeded R/W lock acquisition
- Add the handshake upcall mechanism, allowing the user-space to
implement generic TLS handshake on kernel's behalf
- Bridge: support per-{Port, VLAN} neighbor suppression, increasing
resilience to nodes failures
- SCTP: add support for Fair Capacity and Weighted Fair Queueing
schedulers
- MPTCP: delay first subflow allocation up to its first usage. This
will allow for later better LSM interaction
- xfrm: Remove inner/outer modes from input/output path. These are
not needed anymore
- WiFi:
- reduced neighbor report (RNR) handling for AP mode
- HW timestamping support
- support for randomized auth/deauth TA for PASN privacy
- per-link debugfs for multi-link
- TC offload support for mac80211 drivers
- mac80211 mesh fast-xmit and fast-rx support
- enable Wi-Fi 7 (EHT) mesh support
Netfilter:
- Add nf_tables 'brouting' support, to force a packet to be routed
instead of being bridged
- Update bridge netfilter and ovs conntrack helpers to handle IPv6
Jumbo packets properly, i.e. fetch the packet length from
hop-by-hop extension header. This is needed for BIT TCP support
- The iptables 32bit compat interface isn't compiled in by default
anymore
- Move ip(6)tables builtin icmp matches to the udptcp one. This has
the advantage that icmp/icmpv6 match doesn't load the
iptables/ip6tables modules anymore when iptables-nft is used
- Extended netlink error report for netdevice in flowtables and
netdev/chains. Allow for incrementally add/delete devices to netdev
basechain. Allow to create netdev chain without device
Driver API:
- Remove redundant Device Control Error Reporting Enable, as PCI core
has already error reporting enabled at enumeration time
- Move Multicast DB netlink handlers to core, allowing devices other
then bridge to use them
- Allow the page_pool to directly recycle the pages from safely
localized NAPI
- Implement lockless TX queue stop/wake combo macros, allowing for
further code de-duplication and sanitization
- Add YNL support for user headers and struct attrs
- Add partial YNL specification for devlink
- Add partial YNL specification for ethtool
- Add tc-mqprio and tc-taprio support for preemptible traffic classes
- Add tx push buf len param to ethtool, specifies the maximum number
of bytes of a transmitted packet a driver can push directly to the
underlying device
- Add basic LED support for switch/phy
- Add NAPI documentation, stop relaying on external links
- Convert dsa_master_ioctl() to netdev notifier. This is a
preparatory work to make the hardware timestamping layer selectable
by user space
- Add transceiver support and improve the error messages for CAN-FD
controllers
New hardware / drivers:
- Ethernet:
- AMD/Pensando core device support
- MediaTek MT7981 SoC
- MediaTek MT7988 SoC
- Broadcom BCM53134 embedded switch
- Texas Instruments CPSW9G ethernet switch
- Qualcomm EMAC3 DWMAC ethernet
- StarFive JH7110 SoC
- NXP CBTX ethernet PHY
- WiFi:
- Apple M1 Pro/Max devices
- RealTek rtl8710bu/rtl8188gu
- RealTek rtl8822bs, rtl8822cs and rtl8821cs SDIO chipset
- Bluetooth:
- Realtek RTL8821CS, RTL8851B, RTL8852BS
- Mediatek MT7663, MT7922
- NXP w8997
- Actions Semi ATS2851
- QTI WCN6855
- Marvell 88W8997
- Can:
- STMicroelectronics bxcan stm32f429
Drivers:
- Ethernet NICs:
- Intel (1G, icg):
- add tracking and reporting of QBV config errors
- add support for configuring max SDU for each Tx queue
- Intel (100G, ice):
- refactor mailbox overflow detection to support Scalable IOV
- GNSS interface optimization
- Intel (i40e):
- support XDP multi-buffer
- nVidia/Mellanox:
- add the support for linux bridge multicast offload
- enable TC offload for egress and engress MACVLAN over bond
- add support for VxLAN GBP encap/decap flows offload
- extend packet offload to fully support libreswan
- support tunnel mode in mlx5 IPsec packet offload
- extend XDP multi-buffer support
- support MACsec VLAN offload
- add support for dynamic msix vectors allocation
- drop RX page_cache and fully use page_pool
- implement thermal zone to report NIC temperature
- Netronome/Corigine:
- add support for multi-zone conntrack offload
- Solarflare/Xilinx:
- support offloading TC VLAN push/pop actions to the MAE
- support TC decap rules
- support unicast PTP
- Other NICs:
- Broadcom (bnxt): enforce software based freq adjustments only on
shared PHC NIC
- RealTek (r8169): refactor to addess ASPM issues during NAPI poll
- Micrel (lan8841): add support for PTP_PF_PEROUT
- Cadence (macb): enable PTP unicast
- Engleder (tsnep): add XDP socket zero-copy support
- virtio-net: implement exact header length guest feature
- veth: add page_pool support for page recycling
- vxlan: add MDB data path support
- gve: add XDP support for GQI-QPL format
- geneve: accept every ethertype
- macvlan: allow some packets to bypass broadcast queue
- mana: add support for jumbo frame
- Ethernet high-speed switches:
- Microchip (sparx5): Add support for TC flower templates
- Ethernet embedded switches:
- Broadcom (b54):
- configure 6318 and 63268 RGMII ports
- Marvell (mv88e6xxx):
- faster C45 bus scan
- Microchip:
- lan966x:
- add support for IS1 VCAP
- better TX/RX from/to CPU performances
- ksz9477: add ETS Qdisc support
- ksz8: enhance static MAC table operations and error handling
- sama7g5: add PTP capability
- NXP (ocelot):
- add support for external ports
- add support for preemptible traffic classes
- Texas Instruments:
- add CPSWxG SGMII support for J7200 and J721E
- Intel WiFi (iwlwifi):
- preparation for Wi-Fi 7 EHT and multi-link support
- EHT (Wi-Fi 7) sniffer support
- hardware timestamping support for some devices/firwmares
- TX beacon protection on newer hardware
- Qualcomm 802.11ax WiFi (ath11k):
- MU-MIMO parameters support
- ack signal support for management packets
- RealTek WiFi (rtw88):
- SDIO bus support
- better support for some SDIO devices (e.g. MAC address from
efuse)
- RealTek WiFi (rtw89):
- HW scan support for 8852b
- better support for 6 GHz scanning
- support for various newer firmware APIs
- framework firmware backwards compatibility
- MediaTek WiFi (mt76):
- P2P support
- mesh A-MSDU support
- EHT (Wi-Fi 7) support
- coredump support"
* tag 'net-next-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2078 commits)
net: phy: hide the PHYLIB_LEDS knob
net: phy: marvell-88x2222: remove unnecessary (void*) conversions
tcp/udp: Fix memleaks of sk and zerocopy skbs with TX timestamp.
net: amd: Fix link leak when verifying config failed
net: phy: marvell: Fix inconsistent indenting in led_blink_set
lan966x: Don't use xdp_frame when action is XDP_TX
tsnep: Add XDP socket zero-copy TX support
tsnep: Add XDP socket zero-copy RX support
tsnep: Move skb receive action to separate function
tsnep: Add functions for queue enable/disable
tsnep: Rework TX/RX queue initialization
tsnep: Replace modulo operation with mask
net: phy: dp83867: Add led_brightness_set support
net: phy: Fix reading LED reg property
drivers: nfc: nfcsim: remove return value check of `dev_dir`
net: phy: dp83867: Remove unnecessary (void*) conversions
net: ethtool: coalesce: try to make user settings stick twice
net: mana: Check if netdev/napi_alloc_frag returns single page
net: mana: Rename mana_refill_rxoob and remove some empty lines
net: veth: add page_pool stats
...
ACPI:
* Improve error reporting when failing to manage SDEI on AGDI device
removal
Assembly routines:
* Improve register constraints so that the compiler can make use of
the zero register instead of moving an immediate #0 into a GPR
* Allow the compiler to allocate the registers used for CAS
instructions
CPU features and system registers:
* Cleanups to the way in which CPU features are identified from the
ID register fields
* Extend system register definition generation to handle Enum types
when defining shared register fields
* Generate definitions for new _EL2 registers and add new fields
for ID_AA64PFR1_EL1
* Allow SVE to be disabled separately from SME on the kernel
command-line
Tracing:
* Support for "direct calls" in ftrace, which enables BPF tracing
for arm64
Kdump:
* Don't bother unmapping the crashkernel from the linear mapping,
which then allows us to use huge (block) mappings and reduce
TLB pressure when a crashkernel is loaded.
Memory management:
* Try again to remove data cache invalidation from the coherent DMA
allocation path
* Simplify the fixmap code by mapping at page granularity
* Allow the kfence pool to be allocated early, preventing the rest
of the linear mapping from being forced to page granularity
Perf and PMU:
* Move CPU PMU code out to drivers/perf/ where it can be reused
by the 32-bit ARM architecture when running on ARMv8 CPUs
* Fix race between CPU PMU probing and pKVM host de-privilege
* Add support for Apple M2 CPU PMU
* Adjust the generic PERF_COUNT_HW_BRANCH_INSTRUCTIONS event
dynamically, depending on what the CPU actually supports
* Minor fixes and cleanups to system PMU drivers
Stack tracing:
* Use the XPACLRI instruction to strip PAC from pointers, rather
than rolling our own function in C
* Remove redundant PAC removal for toolchains that handle this in
their builtins
* Make backtracing more resilient in the face of instrumentation
Miscellaneous:
* Fix single-step with KGDB
* Remove harmless warning when 'nokaslr' is passed on the kernel
command-line
* Minor fixes and cleanups across the board
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Will Deacon:
"ACPI:
- Improve error reporting when failing to manage SDEI on AGDI device
removal
Assembly routines:
- Improve register constraints so that the compiler can make use of
the zero register instead of moving an immediate #0 into a GPR
- Allow the compiler to allocate the registers used for CAS
instructions
CPU features and system registers:
- Cleanups to the way in which CPU features are identified from the
ID register fields
- Extend system register definition generation to handle Enum types
when defining shared register fields
- Generate definitions for new _EL2 registers and add new fields for
ID_AA64PFR1_EL1
- Allow SVE to be disabled separately from SME on the kernel
command-line
Tracing:
- Support for "direct calls" in ftrace, which enables BPF tracing for
arm64
Kdump:
- Don't bother unmapping the crashkernel from the linear mapping,
which then allows us to use huge (block) mappings and reduce TLB
pressure when a crashkernel is loaded.
Memory management:
- Try again to remove data cache invalidation from the coherent DMA
allocation path
- Simplify the fixmap code by mapping at page granularity
- Allow the kfence pool to be allocated early, preventing the rest of
the linear mapping from being forced to page granularity
Perf and PMU:
- Move CPU PMU code out to drivers/perf/ where it can be reused by
the 32-bit ARM architecture when running on ARMv8 CPUs
- Fix race between CPU PMU probing and pKVM host de-privilege
- Add support for Apple M2 CPU PMU
- Adjust the generic PERF_COUNT_HW_BRANCH_INSTRUCTIONS event
dynamically, depending on what the CPU actually supports
- Minor fixes and cleanups to system PMU drivers
Stack tracing:
- Use the XPACLRI instruction to strip PAC from pointers, rather than
rolling our own function in C
- Remove redundant PAC removal for toolchains that handle this in
their builtins
- Make backtracing more resilient in the face of instrumentation
Miscellaneous:
- Fix single-step with KGDB
- Remove harmless warning when 'nokaslr' is passed on the kernel
command-line
- Minor fixes and cleanups across the board"
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (72 commits)
KVM: arm64: Ensure CPU PMU probes before pKVM host de-privilege
arm64: kexec: include reboot.h
arm64: delete dead code in this_cpu_set_vectors()
arm64/cpufeature: Use helper macro to specify ID register for capabilites
drivers/perf: hisi: add NULL check for name
drivers/perf: hisi: Remove redundant initialized of pmu->name
arm64/cpufeature: Consistently use symbolic constants for min_field_value
arm64/cpufeature: Pull out helper for CPUID register definitions
arm64/sysreg: Convert HFGITR_EL2 to automatic generation
ACPI: AGDI: Improve error reporting for problems during .remove()
arm64: kernel: Fix kernel warning when nokaslr is passed to commandline
perf/arm-cmn: Fix port detection for CMN-700
arm64: kgdb: Set PSTATE.SS to 1 to re-enable single-step
arm64: move PAC masks to <asm/pointer_auth.h>
arm64: use XPACLRI to strip PAC
arm64: avoid redundant PAC stripping in __builtin_return_address()
arm64/sme: Fix some comments of ARM SME
arm64/signal: Alloc tpidr2 sigframe after checking system_supports_tpidr2()
arm64/signal: Use system_supports_tpidr2() to check TPIDR2
arm64/idreg: Don't disable SME when disabling SVE
...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'pull-fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs fget updates from Al Viro:
"fget() to fdget() conversions"
* tag 'pull-fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fuse_dev_ioctl(): switch to fdget()
cgroup_get_from_fd(): switch to fdget_raw()
bpf: switch to fdget_raw()
build_mount_idmapped(): switch to fdget()
kill the last remaining user of proc_ns_fget()
SVM-SEV: convert the rest of fget() uses to fdget() in there
convert sgx_set_attribute() to fdget()/fdput()
convert setns(2) to fdget()/fdput()
The tracing recursion prevention mechanism must be protected by rcu, that
leaves __rcu_read_{lock,unlock} unprotected by this mechanism. If we trace
them, the recursion will happen. Let's add them into the btf id deny list.
When CONFIG_PREEMPT_RCU is enabled, it can be reproduced with a simple bpf
program as such:
SEC("fentry/__rcu_read_lock")
int fentry_run()
{
return 0;
}
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20230424161104.3737-2-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
As reported by Kumar in [0], the shared ownership implementation for BPF
programs has some race conditions which need to be addressed before it
can safely be used. This patch does so in a minimal way instead of
ripping out shared ownership entirely, as proper fixes for the issues
raised will follow ASAP, at which point this patch's commit can be
reverted to re-enable shared ownership.
The patch removes the ability to call bpf_refcount_acquire_impl from BPF
programs. Programs can only bump refcount and obtain a new owning
reference using this kfunc, so removing the ability to call it
effectively disables shared ownership.
Instead of changing success / failure expectations for
bpf_refcount-related selftests, this patch just disables them from
running for now.
[0]: https://lore.kernel.org/bpf/d7hyspcow5wtjcmw4fugdgyp3fwhljwuscp3xyut5qnwivyeru@ysdq543otzv2/
Reported-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230424204321.2680232-1-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:
====================
pull-request: bpf-next 2023-04-21
We've added 71 non-merge commits during the last 8 day(s) which contain
a total of 116 files changed, 13397 insertions(+), 8896 deletions(-).
The main changes are:
1) Add a new BPF netfilter program type and minimal support to hook
BPF programs to netfilter hooks such as prerouting or forward,
from Florian Westphal.
2) Fix race between btf_put and btf_idr walk which caused a deadlock,
from Alexei Starovoitov.
3) Second big batch to migrate test_verifier unit tests into test_progs
for ease of readability and debugging, from Eduard Zingerman.
4) Add support for refcounted local kptrs to the verifier for allowing
shared ownership, useful for adding a node to both the BPF list and
rbtree, from Dave Marchevsky.
5) Migrate bpf_for(), bpf_for_each() and bpf_repeat() macros from BPF
selftests into libbpf-provided bpf_helpers.h header and improve
kfunc handling, from Andrii Nakryiko.
6) Support 64-bit pointers to kfuncs needed for archs like s390x,
from Ilya Leoshkevich.
7) Support BPF progs under getsockopt with a NULL optval,
from Stanislav Fomichev.
8) Improve verifier u32 scalar equality checking in order to enable
LLVM transformations which earlier had to be disabled specifically
for BPF backend, from Yonghong Song.
9) Extend bpftool's struct_ops object loading to support links,
from Kui-Feng Lee.
10) Add xsk selftest follow-up fixes for hugepage allocated umem,
from Magnus Karlsson.
11) Support BPF redirects from tc BPF to ifb devices,
from Daniel Borkmann.
12) Add BPF support for integer type when accessing variable length
arrays, from Feng Zhou.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (71 commits)
selftests/bpf: verifier/value_ptr_arith converted to inline assembly
selftests/bpf: verifier/value_illegal_alu converted to inline assembly
selftests/bpf: verifier/unpriv converted to inline assembly
selftests/bpf: verifier/subreg converted to inline assembly
selftests/bpf: verifier/spin_lock converted to inline assembly
selftests/bpf: verifier/sock converted to inline assembly
selftests/bpf: verifier/search_pruning converted to inline assembly
selftests/bpf: verifier/runtime_jit converted to inline assembly
selftests/bpf: verifier/regalloc converted to inline assembly
selftests/bpf: verifier/ref_tracking converted to inline assembly
selftests/bpf: verifier/map_ptr_mixing converted to inline assembly
selftests/bpf: verifier/map_in_map converted to inline assembly
selftests/bpf: verifier/lwt converted to inline assembly
selftests/bpf: verifier/loops1 converted to inline assembly
selftests/bpf: verifier/jeq_infer_not_null converted to inline assembly
selftests/bpf: verifier/direct_packet_access converted to inline assembly
selftests/bpf: verifier/d_path converted to inline assembly
selftests/bpf: verifier/ctx converted to inline assembly
selftests/bpf: verifier/btf_ctx_access converted to inline assembly
selftests/bpf: verifier/bpf_get_stack converted to inline assembly
...
====================
Link: https://lore.kernel.org/r/20230421211035.9111-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This adds minimal support for BPF_PROG_TYPE_NETFILTER bpf programs
that will be invoked via the NF_HOOK() points in the ip stack.
Invocation incurs an indirect call. This is not a necessity: Its
possible to add 'DEFINE_BPF_DISPATCHER(nf_progs)' and handle the
program invocation with the same method already done for xdp progs.
This isn't done here to keep the size of this chunk down.
Verifier restricts verdicts to either DROP or ACCEPT.
Signed-off-by: Florian Westphal <fw@strlen.de>
Link: https://lore.kernel.org/r/20230421170300.24115-3-fw@strlen.de
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add bpf_link support skeleton. To keep this reviewable, no bpf program
can be invoked yet, if a program is attached only a c-stub is called and
not the actual bpf program.
Defaults to 'y' if both netfilter and bpf syscall are enabled in kconfig.
Uapi example usage:
union bpf_attr attr = { };
attr.link_create.prog_fd = progfd;
attr.link_create.attach_type = 0; /* unused */
attr.link_create.netfilter.pf = PF_INET;
attr.link_create.netfilter.hooknum = NF_INET_LOCAL_IN;
attr.link_create.netfilter.priority = -128;
err = bpf(BPF_LINK_CREATE, &attr, sizeof(attr));
... this would attach progfd to ipv4:input hook.
Such hook gets removed automatically if the calling program exits.
BPF_NETFILTER program invocation is added in followup change.
NF_HOOK_OP_BPF enum will eventually be read from nfnetlink_hook, it
allows to tell userspace which program is attached at the given hook
when user runs 'nft hook list' command rather than just the priority
and not-very-helpful 'this hook runs a bpf prog but I can't tell which
one'.
Will also be used to disallow registration of two bpf programs with
same priority in a followup patch.
v4: arm32 cmpxchg only supports 32bit operand
s/prio/priority/
v3: restrict prog attachment to ip/ip6 for now, lets lift restrictions if
more use cases pop up (arptables, ebtables, netdev ingress/egress etc).
Signed-off-by: Florian Westphal <fw@strlen.de>
Link: https://lore.kernel.org/r/20230421170300.24115-2-fw@strlen.de
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When calculating the address of the refcount_t struct within a local
kptr, bpf_refcount_acquire_impl should add refcount_off bytes to the
address of the local kptr. Due to some missing parens, the function is
incorrectly adding sizeof(refcount_t) * refcount_off bytes. This patch
fixes the calculation.
Due to the incorrect calculation, bpf_refcount_acquire_impl was trying
to refcount_inc some memory well past the end of local kptrs, resulting
in kasan and refcount complaints, as reported in [0]. In that thread,
Florian and Eduard discovered that bpf selftests written in the new
style - with __success and an expected __retval, specifically - were
not actually being run. As a result, selftests added in bpf_refcount
series weren't really exercising this behavior, and thus didn't unearth
the bug.
With this fixed behavior it's safe to revert commit 7c4b96c000
("selftests/bpf: disable program test run for progs/refcounted_kptr.c"),
this patch does so.
[0] https://lore.kernel.org/bpf/ZEEp+j22imoN6rn9@strlen.de/
Fixes: 7c50b1cb76 ("bpf: Add bpf_refcount_acquire kfunc")
Reported-by: Florian Westphal <fw@strlen.de>
Reported-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20230421074431.3548349-1-davemarchevsky@fb.com
Florian and Eduard reported hard dead lock:
[ 58.433327] _raw_spin_lock_irqsave+0x40/0x50
[ 58.433334] btf_put+0x43/0x90
[ 58.433338] bpf_find_btf_id+0x157/0x240
[ 58.433353] btf_parse_fields+0x921/0x11c0
This happens since btf->refcount can be 1 at the time of btf_put() and
btf_put() will call btf_free_id() which will try to grab btf_idr_lock
and will dead lock.
Avoid the issue by doing btf_put() without locking.
Fixes: 3d78417b60 ("bpf: Add bpf_btf_find_by_name_kind() helper.")
Fixes: 1e89106da2 ("bpf: Add bpf_core_add_cands() and wire it into bpf_core_apply_relo_insn().")
Reported-by: Florian Westphal <fw@strlen.de>
Reported-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20230421014901.70908-1-alexei.starovoitov@gmail.com
Juan Jose et al reported an issue found via fuzzing where the verifier's
pruning logic prematurely marks a program path as safe.
Consider the following program:
0: (b7) r6 = 1024
1: (b7) r7 = 0
2: (b7) r8 = 0
3: (b7) r9 = -2147483648
4: (97) r6 %= 1025
5: (05) goto pc+0
6: (bd) if r6 <= r9 goto pc+2
7: (97) r6 %= 1
8: (b7) r9 = 0
9: (bd) if r6 <= r9 goto pc+1
10: (b7) r6 = 0
11: (b7) r0 = 0
12: (63) *(u32 *)(r10 -4) = r0
13: (18) r4 = 0xffff888103693400 // map_ptr(ks=4,vs=48)
15: (bf) r1 = r4
16: (bf) r2 = r10
17: (07) r2 += -4
18: (85) call bpf_map_lookup_elem#1
19: (55) if r0 != 0x0 goto pc+1
20: (95) exit
21: (77) r6 >>= 10
22: (27) r6 *= 8192
23: (bf) r1 = r0
24: (0f) r0 += r6
25: (79) r3 = *(u64 *)(r0 +0)
26: (7b) *(u64 *)(r1 +0) = r3
27: (95) exit
The verifier treats this as safe, leading to oob read/write access due
to an incorrect verifier conclusion:
func#0 @0
0: R1=ctx(off=0,imm=0) R10=fp0
0: (b7) r6 = 1024 ; R6_w=1024
1: (b7) r7 = 0 ; R7_w=0
2: (b7) r8 = 0 ; R8_w=0
3: (b7) r9 = -2147483648 ; R9_w=-2147483648
4: (97) r6 %= 1025 ; R6_w=scalar()
5: (05) goto pc+0
6: (bd) if r6 <= r9 goto pc+2 ; R6_w=scalar(umin=18446744071562067969,var_off=(0xffffffff00000000; 0xffffffff)) R9_w=-2147483648
7: (97) r6 %= 1 ; R6_w=scalar()
8: (b7) r9 = 0 ; R9=0
9: (bd) if r6 <= r9 goto pc+1 ; R6=scalar(umin=1) R9=0
10: (b7) r6 = 0 ; R6_w=0
11: (b7) r0 = 0 ; R0_w=0
12: (63) *(u32 *)(r10 -4) = r0
last_idx 12 first_idx 9
regs=1 stack=0 before 11: (b7) r0 = 0
13: R0_w=0 R10=fp0 fp-8=0000????
13: (18) r4 = 0xffff8ad3886c2a00 ; R4_w=map_ptr(off=0,ks=4,vs=48,imm=0)
15: (bf) r1 = r4 ; R1_w=map_ptr(off=0,ks=4,vs=48,imm=0) R4_w=map_ptr(off=0,ks=4,vs=48,imm=0)
16: (bf) r2 = r10 ; R2_w=fp0 R10=fp0
17: (07) r2 += -4 ; R2_w=fp-4
18: (85) call bpf_map_lookup_elem#1 ; R0=map_value_or_null(id=1,off=0,ks=4,vs=48,imm=0)
19: (55) if r0 != 0x0 goto pc+1 ; R0=0
20: (95) exit
from 19 to 21: R0=map_value(off=0,ks=4,vs=48,imm=0) R6=0 R7=0 R8=0 R9=0 R10=fp0 fp-8=mmmm????
21: (77) r6 >>= 10 ; R6_w=0
22: (27) r6 *= 8192 ; R6_w=0
23: (bf) r1 = r0 ; R0=map_value(off=0,ks=4,vs=48,imm=0) R1_w=map_value(off=0,ks=4,vs=48,imm=0)
24: (0f) r0 += r6
last_idx 24 first_idx 19
regs=40 stack=0 before 23: (bf) r1 = r0
regs=40 stack=0 before 22: (27) r6 *= 8192
regs=40 stack=0 before 21: (77) r6 >>= 10
regs=40 stack=0 before 19: (55) if r0 != 0x0 goto pc+1
parent didn't have regs=40 stack=0 marks: R0_rw=map_value_or_null(id=1,off=0,ks=4,vs=48,imm=0) R6_rw=P0 R7=0 R8=0 R9=0 R10=fp0 fp-8=mmmm????
last_idx 18 first_idx 9
regs=40 stack=0 before 18: (85) call bpf_map_lookup_elem#1
regs=40 stack=0 before 17: (07) r2 += -4
regs=40 stack=0 before 16: (bf) r2 = r10
regs=40 stack=0 before 15: (bf) r1 = r4
regs=40 stack=0 before 13: (18) r4 = 0xffff8ad3886c2a00
regs=40 stack=0 before 12: (63) *(u32 *)(r10 -4) = r0
regs=40 stack=0 before 11: (b7) r0 = 0
regs=40 stack=0 before 10: (b7) r6 = 0
25: (79) r3 = *(u64 *)(r0 +0) ; R0_w=map_value(off=0,ks=4,vs=48,imm=0) R3_w=scalar()
26: (7b) *(u64 *)(r1 +0) = r3 ; R1_w=map_value(off=0,ks=4,vs=48,imm=0) R3_w=scalar()
27: (95) exit
from 9 to 11: R1=ctx(off=0,imm=0) R6=0 R7=0 R8=0 R9=0 R10=fp0
11: (b7) r0 = 0 ; R0_w=0
12: (63) *(u32 *)(r10 -4) = r0
last_idx 12 first_idx 11
regs=1 stack=0 before 11: (b7) r0 = 0
13: R0_w=0 R10=fp0 fp-8=0000????
13: (18) r4 = 0xffff8ad3886c2a00 ; R4_w=map_ptr(off=0,ks=4,vs=48,imm=0)
15: (bf) r1 = r4 ; R1_w=map_ptr(off=0,ks=4,vs=48,imm=0) R4_w=map_ptr(off=0,ks=4,vs=48,imm=0)
16: (bf) r2 = r10 ; R2_w=fp0 R10=fp0
17: (07) r2 += -4 ; R2_w=fp-4
18: (85) call bpf_map_lookup_elem#1
frame 0: propagating r6
last_idx 19 first_idx 11
regs=40 stack=0 before 18: (85) call bpf_map_lookup_elem#1
regs=40 stack=0 before 17: (07) r2 += -4
regs=40 stack=0 before 16: (bf) r2 = r10
regs=40 stack=0 before 15: (bf) r1 = r4
regs=40 stack=0 before 13: (18) r4 = 0xffff8ad3886c2a00
regs=40 stack=0 before 12: (63) *(u32 *)(r10 -4) = r0
regs=40 stack=0 before 11: (b7) r0 = 0
parent didn't have regs=40 stack=0 marks: R1=ctx(off=0,imm=0) R6_r=P0 R7=0 R8=0 R9=0 R10=fp0
last_idx 9 first_idx 9
regs=40 stack=0 before 9: (bd) if r6 <= r9 goto pc+1
parent didn't have regs=40 stack=0 marks: R1=ctx(off=0,imm=0) R6_rw=Pscalar() R7_w=0 R8_w=0 R9_rw=0 R10=fp0
last_idx 8 first_idx 0
regs=40 stack=0 before 8: (b7) r9 = 0
regs=40 stack=0 before 7: (97) r6 %= 1
regs=40 stack=0 before 6: (bd) if r6 <= r9 goto pc+2
regs=40 stack=0 before 5: (05) goto pc+0
regs=40 stack=0 before 4: (97) r6 %= 1025
regs=40 stack=0 before 3: (b7) r9 = -2147483648
regs=40 stack=0 before 2: (b7) r8 = 0
regs=40 stack=0 before 1: (b7) r7 = 0
regs=40 stack=0 before 0: (b7) r6 = 1024
19: safe
frame 0: propagating r6
last_idx 9 first_idx 0
regs=40 stack=0 before 6: (bd) if r6 <= r9 goto pc+2
regs=40 stack=0 before 5: (05) goto pc+0
regs=40 stack=0 before 4: (97) r6 %= 1025
regs=40 stack=0 before 3: (b7) r9 = -2147483648
regs=40 stack=0 before 2: (b7) r8 = 0
regs=40 stack=0 before 1: (b7) r7 = 0
regs=40 stack=0 before 0: (b7) r6 = 1024
from 6 to 9: safe
verification time 110 usec
stack depth 4
processed 36 insns (limit 1000000) max_states_per_insn 0 total_states 3 peak_states 3 mark_read 2
The verifier considers this program as safe by mistakenly pruning unsafe
code paths. In the above func#0, code lines 0-10 are of interest. In line
0-3 registers r6 to r9 are initialized with known scalar values. In line 4
the register r6 is reset to an unknown scalar given the verifier does not
track modulo operations. Due to this, the verifier can also not determine
precisely which branches in line 6 and 9 are taken, therefore it needs to
explore them both.
As can be seen, the verifier starts with exploring the false/fall-through
paths first. The 'from 19 to 21' path has both r6=0 and r9=0 and the pointer
arithmetic on r0 += r6 is therefore considered safe. Given the arithmetic,
r6 is correctly marked for precision tracking where backtracking kicks in
where it walks back the current path all the way where r6 was set to 0 in
the fall-through branch.
Next, the pruning logics pops the path 'from 9 to 11' from the stack. Also
here, the state of the registers is the same, that is, r6=0 and r9=0, so
that at line 19 the path can be pruned as it is considered safe. It is
interesting to note that the conditional in line 9 turned r6 into a more
precise state, that is, in the fall-through path at the beginning of line
10, it is R6=scalar(umin=1), and in the branch-taken path (which is analyzed
here) at the beginning of line 11, r6 turned into a known const r6=0 as
r9=0 prior to that and therefore (unsigned) r6 <= 0 concludes that r6 must
be 0 (**):
[...] ; R6_w=scalar()
9: (bd) if r6 <= r9 goto pc+1 ; R6=scalar(umin=1) R9=0
[...]
from 9 to 11: R1=ctx(off=0,imm=0) R6=0 R7=0 R8=0 R9=0 R10=fp0
[...]
The next path is 'from 6 to 9'. The verifier considers the old and current
state equivalent, and therefore prunes the search incorrectly. Looking into
the two states which are being compared by the pruning logic at line 9, the
old state consists of R6_rwD=Pscalar() R9_rwD=0 R10=fp0 and the new state
consists of R1=ctx(off=0,imm=0) R6_w=scalar(umax=18446744071562067968)
R7_w=0 R8_w=0 R9_w=-2147483648 R10=fp0. While r6 had the reg->precise flag
correctly set in the old state, r9 did not. Both r6'es are considered as
equivalent given the old one is a superset of the current, more precise one,
however, r9's actual values (0 vs 0x80000000) mismatch. Given the old r9
did not have reg->precise flag set, the verifier does not consider the
register as contributing to the precision state of r6, and therefore it
considered both r9 states as equivalent. However, for this specific pruned
path (which is also the actual path taken at runtime), register r6 will be
0x400 and r9 0x80000000 when reaching line 21, thus oob-accessing the map.
The purpose of precision tracking is to initially mark registers (including
spilled ones) as imprecise to help verifier's pruning logic finding equivalent
states it can then prune if they don't contribute to the program's safety
aspects. For example, if registers are used for pointer arithmetic or to pass
constant length to a helper, then the verifier sets reg->precise flag and
backtracks the BPF program instruction sequence and chain of verifier states
to ensure that the given register or stack slot including their dependencies
are marked as precisely tracked scalar. This also includes any other registers
and slots that contribute to a tracked state of given registers/stack slot.
This backtracking relies on recorded jmp_history and is able to traverse
entire chain of parent states. This process ends only when all the necessary
registers/slots and their transitive dependencies are marked as precise.
The backtrack_insn() is called from the current instruction up to the first
instruction, and its purpose is to compute a bitmask of registers and stack
slots that need precision tracking in the parent's verifier state. For example,
if a current instruction is r6 = r7, then r6 needs precision after this
instruction and r7 needs precision before this instruction, that is, in the
parent state. Hence for the latter r7 is marked and r6 unmarked.
For the class of jmp/jmp32 instructions, backtrack_insn() today only looks
at call and exit instructions and for all other conditionals the masks
remain as-is. However, in the given situation register r6 has a dependency
on r9 (as described above in **), so also that one needs to be marked for
precision tracking. In other words, if an imprecise register influences a
precise one, then the imprecise register should also be marked precise.
Meaning, in the parent state both dest and src register need to be tracked
for precision and therefore the marking must be more conservative by setting
reg->precise flag for both. The precision propagation needs to cover both
for the conditional: if the src reg was marked but not the dst reg and vice
versa.
After the fix the program is correctly rejected:
func#0 @0
0: R1=ctx(off=0,imm=0) R10=fp0
0: (b7) r6 = 1024 ; R6_w=1024
1: (b7) r7 = 0 ; R7_w=0
2: (b7) r8 = 0 ; R8_w=0
3: (b7) r9 = -2147483648 ; R9_w=-2147483648
4: (97) r6 %= 1025 ; R6_w=scalar()
5: (05) goto pc+0
6: (bd) if r6 <= r9 goto pc+2 ; R6_w=scalar(umin=18446744071562067969,var_off=(0xffffffff80000000; 0x7fffffff),u32_min=-2147483648) R9_w=-2147483648
7: (97) r6 %= 1 ; R6_w=scalar()
8: (b7) r9 = 0 ; R9=0
9: (bd) if r6 <= r9 goto pc+1 ; R6=scalar(umin=1) R9=0
10: (b7) r6 = 0 ; R6_w=0
11: (b7) r0 = 0 ; R0_w=0
12: (63) *(u32 *)(r10 -4) = r0
last_idx 12 first_idx 9
regs=1 stack=0 before 11: (b7) r0 = 0
13: R0_w=0 R10=fp0 fp-8=0000????
13: (18) r4 = 0xffff9290dc5bfe00 ; R4_w=map_ptr(off=0,ks=4,vs=48,imm=0)
15: (bf) r1 = r4 ; R1_w=map_ptr(off=0,ks=4,vs=48,imm=0) R4_w=map_ptr(off=0,ks=4,vs=48,imm=0)
16: (bf) r2 = r10 ; R2_w=fp0 R10=fp0
17: (07) r2 += -4 ; R2_w=fp-4
18: (85) call bpf_map_lookup_elem#1 ; R0=map_value_or_null(id=1,off=0,ks=4,vs=48,imm=0)
19: (55) if r0 != 0x0 goto pc+1 ; R0=0
20: (95) exit
from 19 to 21: R0=map_value(off=0,ks=4,vs=48,imm=0) R6=0 R7=0 R8=0 R9=0 R10=fp0 fp-8=mmmm????
21: (77) r6 >>= 10 ; R6_w=0
22: (27) r6 *= 8192 ; R6_w=0
23: (bf) r1 = r0 ; R0=map_value(off=0,ks=4,vs=48,imm=0) R1_w=map_value(off=0,ks=4,vs=48,imm=0)
24: (0f) r0 += r6
last_idx 24 first_idx 19
regs=40 stack=0 before 23: (bf) r1 = r0
regs=40 stack=0 before 22: (27) r6 *= 8192
regs=40 stack=0 before 21: (77) r6 >>= 10
regs=40 stack=0 before 19: (55) if r0 != 0x0 goto pc+1
parent didn't have regs=40 stack=0 marks: R0_rw=map_value_or_null(id=1,off=0,ks=4,vs=48,imm=0) R6_rw=P0 R7=0 R8=0 R9=0 R10=fp0 fp-8=mmmm????
last_idx 18 first_idx 9
regs=40 stack=0 before 18: (85) call bpf_map_lookup_elem#1
regs=40 stack=0 before 17: (07) r2 += -4
regs=40 stack=0 before 16: (bf) r2 = r10
regs=40 stack=0 before 15: (bf) r1 = r4
regs=40 stack=0 before 13: (18) r4 = 0xffff9290dc5bfe00
regs=40 stack=0 before 12: (63) *(u32 *)(r10 -4) = r0
regs=40 stack=0 before 11: (b7) r0 = 0
regs=40 stack=0 before 10: (b7) r6 = 0
25: (79) r3 = *(u64 *)(r0 +0) ; R0_w=map_value(off=0,ks=4,vs=48,imm=0) R3_w=scalar()
26: (7b) *(u64 *)(r1 +0) = r3 ; R1_w=map_value(off=0,ks=4,vs=48,imm=0) R3_w=scalar()
27: (95) exit
from 9 to 11: R1=ctx(off=0,imm=0) R6=0 R7=0 R8=0 R9=0 R10=fp0
11: (b7) r0 = 0 ; R0_w=0
12: (63) *(u32 *)(r10 -4) = r0
last_idx 12 first_idx 11
regs=1 stack=0 before 11: (b7) r0 = 0
13: R0_w=0 R10=fp0 fp-8=0000????
13: (18) r4 = 0xffff9290dc5bfe00 ; R4_w=map_ptr(off=0,ks=4,vs=48,imm=0)
15: (bf) r1 = r4 ; R1_w=map_ptr(off=0,ks=4,vs=48,imm=0) R4_w=map_ptr(off=0,ks=4,vs=48,imm=0)
16: (bf) r2 = r10 ; R2_w=fp0 R10=fp0
17: (07) r2 += -4 ; R2_w=fp-4
18: (85) call bpf_map_lookup_elem#1
frame 0: propagating r6
last_idx 19 first_idx 11
regs=40 stack=0 before 18: (85) call bpf_map_lookup_elem#1
regs=40 stack=0 before 17: (07) r2 += -4
regs=40 stack=0 before 16: (bf) r2 = r10
regs=40 stack=0 before 15: (bf) r1 = r4
regs=40 stack=0 before 13: (18) r4 = 0xffff9290dc5bfe00
regs=40 stack=0 before 12: (63) *(u32 *)(r10 -4) = r0
regs=40 stack=0 before 11: (b7) r0 = 0
parent didn't have regs=40 stack=0 marks: R1=ctx(off=0,imm=0) R6_r=P0 R7=0 R8=0 R9=0 R10=fp0
last_idx 9 first_idx 9
regs=40 stack=0 before 9: (bd) if r6 <= r9 goto pc+1
parent didn't have regs=240 stack=0 marks: R1=ctx(off=0,imm=0) R6_rw=Pscalar() R7_w=0 R8_w=0 R9_rw=P0 R10=fp0
last_idx 8 first_idx 0
regs=240 stack=0 before 8: (b7) r9 = 0
regs=40 stack=0 before 7: (97) r6 %= 1
regs=40 stack=0 before 6: (bd) if r6 <= r9 goto pc+2
regs=240 stack=0 before 5: (05) goto pc+0
regs=240 stack=0 before 4: (97) r6 %= 1025
regs=240 stack=0 before 3: (b7) r9 = -2147483648
regs=40 stack=0 before 2: (b7) r8 = 0
regs=40 stack=0 before 1: (b7) r7 = 0
regs=40 stack=0 before 0: (b7) r6 = 1024
19: safe
from 6 to 9: R1=ctx(off=0,imm=0) R6_w=scalar(umax=18446744071562067968) R7_w=0 R8_w=0 R9_w=-2147483648 R10=fp0
9: (bd) if r6 <= r9 goto pc+1
last_idx 9 first_idx 0
regs=40 stack=0 before 6: (bd) if r6 <= r9 goto pc+2
regs=240 stack=0 before 5: (05) goto pc+0
regs=240 stack=0 before 4: (97) r6 %= 1025
regs=240 stack=0 before 3: (b7) r9 = -2147483648
regs=40 stack=0 before 2: (b7) r8 = 0
regs=40 stack=0 before 1: (b7) r7 = 0
regs=40 stack=0 before 0: (b7) r6 = 1024
last_idx 9 first_idx 0
regs=200 stack=0 before 6: (bd) if r6 <= r9 goto pc+2
regs=240 stack=0 before 5: (05) goto pc+0
regs=240 stack=0 before 4: (97) r6 %= 1025
regs=240 stack=0 before 3: (b7) r9 = -2147483648
regs=40 stack=0 before 2: (b7) r8 = 0
regs=40 stack=0 before 1: (b7) r7 = 0
regs=40 stack=0 before 0: (b7) r6 = 1024
11: R6=scalar(umax=18446744071562067968) R9=-2147483648
11: (b7) r0 = 0 ; R0_w=0
12: (63) *(u32 *)(r10 -4) = r0
last_idx 12 first_idx 11
regs=1 stack=0 before 11: (b7) r0 = 0
13: R0_w=0 R10=fp0 fp-8=0000????
13: (18) r4 = 0xffff9290dc5bfe00 ; R4_w=map_ptr(off=0,ks=4,vs=48,imm=0)
15: (bf) r1 = r4 ; R1_w=map_ptr(off=0,ks=4,vs=48,imm=0) R4_w=map_ptr(off=0,ks=4,vs=48,imm=0)
16: (bf) r2 = r10 ; R2_w=fp0 R10=fp0
17: (07) r2 += -4 ; R2_w=fp-4
18: (85) call bpf_map_lookup_elem#1 ; R0_w=map_value_or_null(id=3,off=0,ks=4,vs=48,imm=0)
19: (55) if r0 != 0x0 goto pc+1 ; R0_w=0
20: (95) exit
from 19 to 21: R0=map_value(off=0,ks=4,vs=48,imm=0) R6=scalar(umax=18446744071562067968) R7=0 R8=0 R9=-2147483648 R10=fp0 fp-8=mmmm????
21: (77) r6 >>= 10 ; R6_w=scalar(umax=18014398507384832,var_off=(0x0; 0x3fffffffffffff))
22: (27) r6 *= 8192 ; R6_w=scalar(smax=9223372036854767616,umax=18446744073709543424,var_off=(0x0; 0xffffffffffffe000),s32_max=2147475456,u32_max=-8192)
23: (bf) r1 = r0 ; R0=map_value(off=0,ks=4,vs=48,imm=0) R1_w=map_value(off=0,ks=4,vs=48,imm=0)
24: (0f) r0 += r6
last_idx 24 first_idx 21
regs=40 stack=0 before 23: (bf) r1 = r0
regs=40 stack=0 before 22: (27) r6 *= 8192
regs=40 stack=0 before 21: (77) r6 >>= 10
parent didn't have regs=40 stack=0 marks: R0_rw=map_value(off=0,ks=4,vs=48,imm=0) R6_r=Pscalar(umax=18446744071562067968) R7=0 R8=0 R9=-2147483648 R10=fp0 fp-8=mmmm????
last_idx 19 first_idx 11
regs=40 stack=0 before 19: (55) if r0 != 0x0 goto pc+1
regs=40 stack=0 before 18: (85) call bpf_map_lookup_elem#1
regs=40 stack=0 before 17: (07) r2 += -4
regs=40 stack=0 before 16: (bf) r2 = r10
regs=40 stack=0 before 15: (bf) r1 = r4
regs=40 stack=0 before 13: (18) r4 = 0xffff9290dc5bfe00
regs=40 stack=0 before 12: (63) *(u32 *)(r10 -4) = r0
regs=40 stack=0 before 11: (b7) r0 = 0
parent didn't have regs=40 stack=0 marks: R1=ctx(off=0,imm=0) R6_rw=Pscalar(umax=18446744071562067968) R7_w=0 R8_w=0 R9_w=-2147483648 R10=fp0
last_idx 9 first_idx 0
regs=40 stack=0 before 9: (bd) if r6 <= r9 goto pc+1
regs=240 stack=0 before 6: (bd) if r6 <= r9 goto pc+2
regs=240 stack=0 before 5: (05) goto pc+0
regs=240 stack=0 before 4: (97) r6 %= 1025
regs=240 stack=0 before 3: (b7) r9 = -2147483648
regs=40 stack=0 before 2: (b7) r8 = 0
regs=40 stack=0 before 1: (b7) r7 = 0
regs=40 stack=0 before 0: (b7) r6 = 1024
math between map_value pointer and register with unbounded min value is not allowed
verification time 886 usec
stack depth 4
processed 49 insns (limit 1000000) max_states_per_insn 1 total_states 5 peak_states 5 mark_read 2
Fixes: b5dc0163d8 ("bpf: precise scalar_value tracking")
Reported-by: Juan Jose Lopez Jaimez <jjlopezjaimez@google.com>
Reported-by: Meador Inge <meadori@google.com>
Reported-by: Simon Scannell <simonscannell@google.com>
Reported-by: Nenad Stojanovski <thenenadx@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Co-developed-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: John Fastabend <john.fastabend@gmail.com>
Reviewed-by: Juan Jose Lopez Jaimez <jjlopezjaimez@google.com>
Reviewed-by: Meador Inge <meadori@google.com>
Reviewed-by: Simon Scannell <simonscannell@google.com>
Make it possible to load lirc program type with just CAP_BPF. There is
nothing exceptional about lirc programs that means they require
SYS_CAP_ADMIN.
In order to attach or detach a lirc program type you need permission to
open /dev/lirc0; if you have permission to do that, you can alter all
sorts of lirc receiving options. Changing the IR protocol decoder is no
different.
Right now on a typical distribution /dev/lirc devices are only
read/write by root. Ideally we would make them group read/write like
other devices so that local users can use them without becoming root.
Signed-off-by: Sean Young <sean@mess.org>
Link: https://lore.kernel.org/r/ZD0ArKpwnDBJZsrE@gofer.mess.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
We've managed to improve the UX for kptrs significantly over the last 9
months. All of the existing use cases which previously had KF_KPTR_GET
kfuncs (struct bpf_cpumask *, struct task_struct *, and struct cgroup *)
have all been updated to be synchronized using RCU. In other words,
their KF_KPTR_GET kfuncs have been removed in favor of KF_RCU |
KF_ACQUIRE kfuncs, with the pointers themselves also being readable from
maps in an RCU read region thanks to the types being RCU safe.
While KF_KPTR_GET was a logical starting point for kptrs, it's become
clear that they're not the correct abstraction. KF_KPTR_GET is a flag
that essentially does nothing other than enforcing that the argument to
a function is a pointer to a referenced kptr map value. At first glance,
that's a useful thing to guarantee to a kfunc. It gives kfuncs the
ability to try and acquire a reference on that kptr without requiring
the BPF prog to do something like this:
struct kptr_type *in_map, *new = NULL;
in_map = bpf_kptr_xchg(&map->value, NULL);
if (in_map) {
new = bpf_kptr_type_acquire(in_map);
in_map = bpf_kptr_xchg(&map->value, in_map);
if (in_map)
bpf_kptr_type_release(in_map);
}
That's clearly a pretty ugly (and racy) UX, and if using KF_KPTR_GET is
the only alternative, it's better than nothing. However, the problem
with any KF_KPTR_GET kfunc lies in the fact that it always requires some
kind of synchronization in order to safely do an opportunistic acquire
of the kptr in the map. This is because a BPF program running on another
CPU could do a bpf_kptr_xchg() on that map value, and free the kptr
after it's been read by the KF_KPTR_GET kfunc. For example, the
now-removed bpf_task_kptr_get() kfunc did the following:
struct task_struct *bpf_task_kptr_get(struct task_struct **pp)
{
struct task_struct *p;
rcu_read_lock();
p = READ_ONCE(*pp);
/* If p is non-NULL, it could still be freed by another CPU,
* so we have to do an opportunistic refcount_inc_not_zero()
* and return NULL if the task will be freed after the
* current RCU read region.
*/
|f (p && !refcount_inc_not_zero(&p->rcu_users))
p = NULL;
rcu_read_unlock();
return p;
}
In other words, the kfunc uses RCU to ensure that the task remains valid
after it's been peeked from the map. However, this is completely
redundant with just defining a KF_RCU kfunc that itself does a
refcount_inc_not_zero(), which is exactly what bpf_task_acquire() now
does.
So, the question of whether KF_KPTR_GET is useful is actually, "Are
there any synchronization mechanisms / safety flags that are required by
certain kptrs, but which are not provided by the verifier to kfuncs?"
The answer to that question today is "No", because every kptr we
currently care about is RCU protected.
Even if the answer ever became "yes", the proper way to support that
referenced kptr type would be to add support for whatever
synchronization mechanism it requires in the verifier, rather than
giving kfuncs a flag that says, "Here's a pointer to a referenced kptr
in a map, do whatever you need to do."
With all that said -- so as to allow us to consolidate the kfunc API,
and simplify the verifier a bit, this patch removes KF_KPTR_GET, and all
relevant logic from the verifier.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230416084928.326135-3-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
All btf_fields in an object are 0-initialized by memset in
bpf_obj_init. This might not be a valid initial state for some field
types, in which case kfuncs that use the type will properly initialize
their input if it's been 0-initialized. Some BPF graph collection types
and kfuncs do this: bpf_list_{head,node} and bpf_rb_node.
An earlier patch in this series added the bpf_refcount field, for which
the 0 state indicates that the refcounted object should be free'd.
bpf_obj_init treats this field specially, setting refcount to 1 instead
of relying on scattered "refcount is 0? Must have just been initialized,
let's set to 1" logic in kfuncs.
This patch extends this treatment to list and rbtree field types,
allowing most scattered initialization logic in kfuncs to be removed.
Note that bpf_{list_head,rb_root} may be inside a BPF map, in which case
they'll be 0-initialized without passing through the newly-added logic,
so scattered initialization logic must remain for these collection root
types.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230415201811.343116-9-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch modifies bpf_rbtree_remove to account for possible failure
due to the input rb_node already not being in any collection.
The function can now return NULL, and does when the aforementioned
scenario occurs. As before, on successful removal an owning reference to
the removed node is returned.
Adding KF_RET_NULL to bpf_rbtree_remove's kfunc flags - now KF_RET_NULL |
KF_ACQUIRE - provides the desired verifier semantics:
* retval must be checked for NULL before use
* if NULL, retval's ref_obj_id is released
* retval is a "maybe acquired" owning ref, not a non-owning ref,
so it will live past end of critical section (bpf_spin_unlock), and
thus can be checked for NULL after the end of the CS
BPF programs must add checks
============================
This does change bpf_rbtree_remove's verifier behavior. BPF program
writers will need to add NULL checks to their programs, but the
resulting UX looks natural:
bpf_spin_lock(&glock);
n = bpf_rbtree_first(&ghead);
if (!n) { /* ... */}
res = bpf_rbtree_remove(&ghead, &n->node);
bpf_spin_unlock(&glock);
if (!res) /* Newly-added check after this patch */
return 1;
n = container_of(res, /* ... */);
/* Do something else with n */
bpf_obj_drop(n);
return 0;
The "if (!res)" check above is the only addition necessary for the above
program to pass verification after this patch.
bpf_rbtree_remove no longer clobbers non-owning refs
====================================================
An issue arises when bpf_rbtree_remove fails, though. Consider this
example:
struct node_data {
long key;
struct bpf_list_node l;
struct bpf_rb_node r;
struct bpf_refcount ref;
};
long failed_sum;
void bpf_prog()
{
struct node_data *n = bpf_obj_new(/* ... */);
struct bpf_rb_node *res;
n->key = 10;
bpf_spin_lock(&glock);
bpf_list_push_back(&some_list, &n->l); /* n is now a non-owning ref */
res = bpf_rbtree_remove(&some_tree, &n->r, /* ... */);
if (!res)
failed_sum += n->key; /* not possible */
bpf_spin_unlock(&glock);
/* if (res) { do something useful and drop } ... */
}
The bpf_rbtree_remove in this example will always fail. Similarly to
bpf_spin_unlock, bpf_rbtree_remove is a non-owning reference
invalidation point. The verifier clobbers all non-owning refs after a
bpf_rbtree_remove call, so the "failed_sum += n->key" line will fail
verification, and in fact there's no good way to get information about
the node which failed to add after the invalidation. This patch removes
non-owning reference invalidation from bpf_rbtree_remove to allow the
above usecase to pass verification. The logic for why this is now
possible is as follows:
Before this series, bpf_rbtree_add couldn't fail and thus assumed that
its input, a non-owning reference, was in the tree. But it's easy to
construct an example where two non-owning references pointing to the same
underlying memory are acquired and passed to rbtree_remove one after
another (see rbtree_api_release_aliasing in
selftests/bpf/progs/rbtree_fail.c).
So it was necessary to clobber non-owning refs to prevent this
case and, more generally, to enforce "non-owning ref is definitely
in some collection" invariant. This series removes that invariant and
the failure / runtime checking added in this patch provide a clean way
to deal with the aliasing issue - just fail to remove.
Because the aliasing issue prevented by clobbering non-owning refs is no
longer an issue, this patch removes the invalidate_non_owning_refs
call from verifier handling of bpf_rbtree_remove. Note that
bpf_spin_unlock - the other caller of invalidate_non_owning_refs -
clobbers non-owning refs for a different reason, so its clobbering
behavior remains unchanged.
No BPF program changes are necessary for programs to remain valid as a
result of this clobbering change. A valid program before this patch
passed verification with its non-owning refs having shorter (or equal)
lifetimes due to more aggressive clobbering.
Also, update existing tests to check bpf_rbtree_remove retval for NULL
where necessary, and move rbtree_api_release_aliasing from
progs/rbtree_fail.c to progs/rbtree.c since it's now expected to pass
verification.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230415201811.343116-8-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Consider this code snippet:
struct node {
long key;
bpf_list_node l;
bpf_rb_node r;
bpf_refcount ref;
}
int some_bpf_prog(void *ctx)
{
struct node *n = bpf_obj_new(/*...*/), *m;
bpf_spin_lock(&glock);
bpf_rbtree_add(&some_tree, &n->r, /* ... */);
m = bpf_refcount_acquire(n);
bpf_rbtree_add(&other_tree, &m->r, /* ... */);
bpf_spin_unlock(&glock);
/* ... */
}
After bpf_refcount_acquire, n and m point to the same underlying memory,
and that node's bpf_rb_node field is being used by the some_tree insert,
so overwriting it as a result of the second insert is an error. In order
to properly support refcounted nodes, the rbtree and list insert
functions must be allowed to fail. This patch adds such support.
The kfuncs bpf_rbtree_add, bpf_list_push_{front,back} are modified to
return an int indicating success/failure, with 0 -> success, nonzero ->
failure.
bpf_obj_drop on failure
=======================
Currently the only reason an insert can fail is the example above: the
bpf_{list,rb}_node is already in use. When such a failure occurs, the
insert kfuncs will bpf_obj_drop the input node. This allows the insert
operations to logically fail without changing their verifier owning ref
behavior, namely the unconditional release_reference of the input
owning ref.
With insert that always succeeds, ownership of the node is always passed
to the collection, since the node always ends up in the collection.
With a possibly-failed insert w/ bpf_obj_drop, ownership of the node
is always passed either to the collection (success), or to bpf_obj_drop
(failure). Regardless, it's correct to continue unconditionally
releasing the input owning ref, as something is always taking ownership
from the calling program on insert.
Keeping owning ref behavior unchanged results in a nice default UX for
insert functions that can fail. If the program's reaction to a failed
insert is "fine, just get rid of this owning ref for me and let me go
on with my business", then there's no reason to check for failure since
that's default behavior. e.g.:
long important_failures = 0;
int some_bpf_prog(void *ctx)
{
struct node *n, *m, *o; /* all bpf_obj_new'd */
bpf_spin_lock(&glock);
bpf_rbtree_add(&some_tree, &n->node, /* ... */);
bpf_rbtree_add(&some_tree, &m->node, /* ... */);
if (bpf_rbtree_add(&some_tree, &o->node, /* ... */)) {
important_failures++;
}
bpf_spin_unlock(&glock);
}
If we instead chose to pass ownership back to the program on failed
insert - by returning NULL on success or an owning ref on failure -
programs would always have to do something with the returned ref on
failure. The most likely action is probably "I'll just get rid of this
owning ref and go about my business", which ideally would look like:
if (n = bpf_rbtree_add(&some_tree, &n->node, /* ... */))
bpf_obj_drop(n);
But bpf_obj_drop isn't allowed in a critical section and inserts must
occur within one, so in reality error handling would become a
hard-to-parse mess.
For refcounted nodes, we can replicate the "pass ownership back to
program on failure" logic with this patch's semantics, albeit in an ugly
way:
struct node *n = bpf_obj_new(/* ... */), *m;
bpf_spin_lock(&glock);
m = bpf_refcount_acquire(n);
if (bpf_rbtree_add(&some_tree, &n->node, /* ... */)) {
/* Do something with m */
}
bpf_spin_unlock(&glock);
bpf_obj_drop(m);
bpf_refcount_acquire is used to simulate "return owning ref on failure".
This should be an uncommon occurrence, though.
Addition of two verifier-fixup'd args to collection inserts
===========================================================
The actual bpf_obj_drop kfunc is
bpf_obj_drop_impl(void *, struct btf_struct_meta *), with bpf_obj_drop
macro populating the second arg with 0 and the verifier later filling in
the arg during insn fixup.
Because bpf_rbtree_add and bpf_list_push_{front,back} now might do
bpf_obj_drop, these kfuncs need a btf_struct_meta parameter that can be
passed to bpf_obj_drop_impl.
Similarly, because the 'node' param to those insert functions is the
bpf_{list,rb}_node within the node type, and bpf_obj_drop expects a
pointer to the beginning of the node, the insert functions need to be
able to find the beginning of the node struct. A second
verifier-populated param is necessary: the offset of {list,rb}_node within the
node type.
These two new params allow the insert kfuncs to correctly call
__bpf_obj_drop_impl:
beginning_of_node = bpf_rb_node_ptr - offset
if (already_inserted)
__bpf_obj_drop_impl(beginning_of_node, btf_struct_meta->record);
Similarly to other kfuncs with "hidden" verifier-populated params, the
insert functions are renamed with _impl prefix and a macro is provided
for common usage. For example, bpf_rbtree_add kfunc is now
bpf_rbtree_add_impl and bpf_rbtree_add is now a macro which sets
"hidden" args to 0.
Due to the two new args BPF progs will need to be recompiled to work
with the new _impl kfuncs.
This patch also rewrites the "hidden argument" explanation to more
directly say why the BPF program writer doesn't need to populate the
arguments with anything meaningful.
How does this new logic affect non-owning references?
=====================================================
Currently, non-owning refs are valid until the end of the critical
section in which they're created. We can make this guarantee because, if
a non-owning ref exists, the referent was added to some collection. The
collection will drop() its nodes when it goes away, but it can't go away
while our program is accessing it, so that's not a problem. If the
referent is removed from the collection in the same CS that it was added
in, it can't be bpf_obj_drop'd until after CS end. Those are the only
two ways to free the referent's memory and neither can happen until
after the non-owning ref's lifetime ends.
On first glance, having these collection insert functions potentially
bpf_obj_drop their input seems like it breaks the "can't be
bpf_obj_drop'd until after CS end" line of reasoning. But we care about
the memory not being _freed_ until end of CS end, and a previous patch
in the series modified bpf_obj_drop such that it doesn't free refcounted
nodes until refcount == 0. So the statement can be more accurately
rewritten as "can't be free'd until after CS end".
We can prove that this rewritten statement holds for any non-owning
reference produced by collection insert functions:
* If the input to the insert function is _not_ refcounted
* We have an owning reference to the input, and can conclude it isn't
in any collection
* Inserting a node in a collection turns owning refs into
non-owning, and since our input type isn't refcounted, there's no
way to obtain additional owning refs to the same underlying
memory
* Because our node isn't in any collection, the insert operation
cannot fail, so bpf_obj_drop will not execute
* If bpf_obj_drop is guaranteed not to execute, there's no risk of
memory being free'd
* Otherwise, the input to the insert function is refcounted
* If the insert operation fails due to the node's list_head or rb_root
already being in some collection, there was some previous successful
insert which passed refcount to the collection
* We have an owning reference to the input, it must have been
acquired via bpf_refcount_acquire, which bumped the refcount
* refcount must be >= 2 since there's a valid owning reference and the
node is already in a collection
* Insert triggering bpf_obj_drop will decr refcount to >= 1, never
resulting in a free
So although we may do bpf_obj_drop during the critical section, this
will never result in memory being free'd, and no changes to non-owning
ref logic are needed in this patch.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230415201811.343116-6-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently, BPF programs can interact with the lifetime of refcounted
local kptrs in the following ways:
bpf_obj_new - Initialize refcount to 1 as part of new object creation
bpf_obj_drop - Decrement refcount and free object if it's 0
collection add - Pass ownership to the collection. No change to
refcount but collection is responsible for
bpf_obj_dropping it
In order to be able to add a refcounted local kptr to multiple
collections we need to be able to increment the refcount and acquire a
new owning reference. This patch adds a kfunc, bpf_refcount_acquire,
implementing such an operation.
bpf_refcount_acquire takes a refcounted local kptr and returns a new
owning reference to the same underlying memory as the input. The input
can be either owning or non-owning. To reinforce why this is safe,
consider the following code snippets:
struct node *n = bpf_obj_new(typeof(*n)); // A
struct node *m = bpf_refcount_acquire(n); // B
In the above snippet, n will be alive with refcount=1 after (A), and
since nothing changes that state before (B), it's obviously safe. If
n is instead added to some rbtree, we can still safely refcount_acquire
it:
struct node *n = bpf_obj_new(typeof(*n));
struct node *m;
bpf_spin_lock(&glock);
bpf_rbtree_add(&groot, &n->node, less); // A
m = bpf_refcount_acquire(n); // B
bpf_spin_unlock(&glock);
In the above snippet, after (A) n is a non-owning reference, and after
(B) m is an owning reference pointing to the same memory as n. Although
n has no ownership of that memory's lifetime, it's guaranteed to be
alive until the end of the critical section, and n would be clobbered if
we were past the end of the critical section, so it's safe to bump
refcount.
Implementation details:
* From verifier's perspective, bpf_refcount_acquire handling is similar
to bpf_obj_new and bpf_obj_drop. Like the former, it returns a new
owning reference matching input type, although like the latter, type
can be inferred from concrete kptr input. Verifier changes in
{check,fixup}_kfunc_call and check_kfunc_args are largely copied from
aforementioned functions' verifier changes.
* An exception to the above is the new KF_ARG_PTR_TO_REFCOUNTED_KPTR
arg, indicated by new "__refcounted_kptr" kfunc arg suffix. This is
necessary in order to handle both owning and non-owning input without
adding special-casing to "__alloc" arg handling. Also a convenient
place to confirm that input type has bpf_refcount field.
* The implemented kfunc is actually bpf_refcount_acquire_impl, with
'hidden' second arg that the verifier sets to the type's struct_meta
in fixup_kfunc_call.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230415201811.343116-5-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
A local kptr is considered 'refcounted' when it is of a type that has a
bpf_refcount field. When such a kptr is created, its refcount should be
initialized to 1; when destroyed, the object should be free'd only if a
refcount decr results in 0 refcount.
Existing logic always frees the underlying memory when destroying a
local kptr, and 0-initializes all btf_record fields. This patch adds
checks for "is local kptr refcounted?" and new logic for that case in
the appropriate places.
This patch focuses on changing existing semantics and thus conspicuously
does _not_ provide a way for BPF programs in increment refcount. That
follows later in the series.
__bpf_obj_drop_impl is modified to do the right thing when it sees a
refcounted type. Container types for graph nodes (list, tree, stashed in
map) are migrated to use __bpf_obj_drop_impl as a destructor for their
nodes instead of each having custom destruction code in their _free
paths. Now that "drop" isn't a synonym for "free" when the type is
refcounted it makes sense to centralize this logic.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230415201811.343116-4-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
A 'struct bpf_refcount' is added to the set of opaque uapi/bpf.h types
meant for use in BPF programs. Similarly to other opaque types like
bpf_spin_lock and bpf_rbtree_node, the verifier needs to know where in
user-defined struct types a bpf_refcount can be located, so necessary
btf_record plumbing is added to enable this. bpf_refcount is sized to
hold a refcount_t.
Similarly to bpf_spin_lock, the offset of a bpf_refcount is cached in
btf_record as refcount_off in addition to being in the field array.
Caching refcount_off makes sense for this field because further patches
in the series will modify functions that take local kptrs (e.g.
bpf_obj_drop) to change their behavior if the type they're operating on
is refcounted. So enabling fast "is this type refcounted?" checks is
desirable.
No such verifier behavior changes are introduced in this patch, just
logic to recognize 'struct bpf_refcount' in btf_record.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230415201811.343116-3-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The btf_field_offs struct contains (offset, size) for btf_record fields,
sorted by offset. btf_field_offs is always used in conjunction with
btf_record, which has btf_field 'fields' array with (offset, type), the
latter of which btf_field_offs' size is derived from via
btf_field_type_size.
This patch adds a size field to struct btf_field and sorts btf_record's
fields by offset, making it possible to get rid of btf_field_offs. Less
data duplication and less code complexity results.
Since btf_field_offs' lifetime closely followed the btf_record used to
populate it, most complexity wins are from removal of initialization
code like:
if (btf_record_successfully_initialized) {
foffs = btf_parse_field_offs(rec);
if (IS_ERR_OR_NULL(foffs))
// free the btf_record and return err
}
Other changes in this patch are pretty mechanical:
* foffs->field_off[i] -> rec->fields[i].offset
* foffs->field_sz[i] -> rec->fields[i].size
* Sort rec->fields in btf_parse_fields before returning
* It's possible that this is necessary independently of other
changes in this patch. btf_record_find in syscall.c expects
btf_record's fields to be sorted by offset, yet there's no
explicit sorting of them before this patch, record's fields are
populated in the order they're read from BTF struct definition.
BTF docs don't say anything about the sortedness of struct fields.
* All functions taking struct btf_field_offs * input now instead take
struct btf_record *. All callsites of these functions already have
access to the correct btf_record.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230415201811.343116-2-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
test_ksyms_module fails to emit a kfunc call targeting a module on
s390x, because the verifier stores the difference between kfunc
address and __bpf_call_base in bpf_insn.imm, which is s32, and modules
are roughly (1 << 42) bytes away from the kernel on s390x.
Fix by keeping BTF id in bpf_insn.imm for BPF_PSEUDO_KFUNC_CALLs,
and storing the absolute address in bpf_kfunc_desc.
Introduce bpf_jit_supports_far_kfunc_call() in order to limit this new
behavior to the s390x JIT. Otherwise other JITs need to be modified,
which is not desired.
Introduce bpf_get_kfunc_addr() instead of exposing both
find_kfunc_desc() and struct bpf_kfunc_desc.
In addition to sorting kfuncs by imm, also sort them by offset, in
order to handle conflicting imms from different modules. Do this on
all architectures in order to simplify code.
Factor out resolving specialized kfuncs (XPD and dynptr) from
fixup_kfunc_call(). This was required in the first place, because
fixup_kfunc_call() uses find_kfunc_desc(), which returns a const
pointer, so it's not possible to modify kfunc addr without stripping
const, which is not nice. It also removes repetition of code like:
if (bpf_jit_supports_far_kfunc_call())
desc->addr = func;
else
insn->imm = BPF_CALL_IMM(func);
and separates kfunc_desc_tab fixups from kfunc_call fixups.
Suggested-by: Jiri Olsa <olsajiri@gmail.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230412230632.885985-1-iii@linux.ibm.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The recursion check in __bpf_prog_enter* and __bpf_prog_exit*
leave preempt_count_{sub,add} unprotected. When attaching trampoline to
them we get panic as follows,
[ 867.843050] BUG: TASK stack guard page was hit at 0000000009d325cf (stack is 0000000046a46a15..00000000537e7b28)
[ 867.843064] stack guard page: 0000 [#1] PREEMPT SMP NOPTI
[ 867.843067] CPU: 8 PID: 11009 Comm: trace Kdump: loaded Not tainted 6.2.0+ #4
[ 867.843100] Call Trace:
[ 867.843101] <TASK>
[ 867.843104] asm_exc_int3+0x3a/0x40
[ 867.843108] RIP: 0010:preempt_count_sub+0x1/0xa0
[ 867.843135] __bpf_prog_enter_recur+0x17/0x90
[ 867.843148] bpf_trampoline_6442468108_0+0x2e/0x1000
[ 867.843154] ? preempt_count_sub+0x1/0xa0
[ 867.843157] preempt_count_sub+0x5/0xa0
[ 867.843159] ? migrate_enable+0xac/0xf0
[ 867.843164] __bpf_prog_exit_recur+0x2d/0x40
[ 867.843168] bpf_trampoline_6442468108_0+0x55/0x1000
...
[ 867.843788] preempt_count_sub+0x5/0xa0
[ 867.843793] ? migrate_enable+0xac/0xf0
[ 867.843829] __bpf_prog_exit_recur+0x2d/0x40
[ 867.843837] BUG: IRQ stack guard page was hit at 0000000099bd8228 (stack is 00000000b23e2bc4..000000006d95af35)
[ 867.843841] BUG: IRQ stack guard page was hit at 000000005ae07924 (stack is 00000000ffd69623..0000000014eb594c)
[ 867.843843] BUG: IRQ stack guard page was hit at 00000000028320f0 (stack is 00000000034b6438..0000000078d1bcec)
[ 867.843842] bpf_trampoline_6442468108_0+0x55/0x1000
...
That is because in __bpf_prog_exit_recur, the preempt_count_{sub,add} are
called after prog->active is decreased.
Fixing this by adding these two functions into btf ids deny list.
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Yafang <laoar.shao@gmail.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Acked-by: Hao Luo <haoluo@google.com>
Link: https://lore.kernel.org/r/20230413025248.79764-1-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Daniel Borkmann says:
====================
pull-request: bpf-next 2023-04-13
We've added 260 non-merge commits during the last 36 day(s) which contain
a total of 356 files changed, 21786 insertions(+), 11275 deletions(-).
The main changes are:
1) Rework BPF verifier log behavior and implement it as a rotating log
by default with the option to retain old-style fixed log behavior,
from Andrii Nakryiko.
2) Adds support for using {FOU,GUE} encap with an ipip device operating
in collect_md mode and add a set of BPF kfuncs for controlling encap
params, from Christian Ehrig.
3) Allow BPF programs to detect at load time whether a particular kfunc
exists or not, and also add support for this in light skeleton,
from Alexei Starovoitov.
4) Optimize hashmap lookups when key size is multiple of 4,
from Anton Protopopov.
5) Enable RCU semantics for task BPF kptrs and allow referenced kptr
tasks to be stored in BPF maps, from David Vernet.
6) Add support for stashing local BPF kptr into a map value via
bpf_kptr_xchg(). This is useful e.g. for rbtree node creation
for new cgroups, from Dave Marchevsky.
7) Fix BTF handling of is_int_ptr to skip modifiers to work around
tracing issues where a program cannot be attached, from Feng Zhou.
8) Migrate a big portion of test_verifier unit tests over to
test_progs -a verifier_* via inline asm to ease {read,debug}ability,
from Eduard Zingerman.
9) Several updates to the instruction-set.rst documentation
which is subject to future IETF standardization
(https://lwn.net/Articles/926882/), from Dave Thaler.
10) Fix BPF verifier in the __reg_bound_offset's 64->32 tnum sub-register
known bits information propagation, from Daniel Borkmann.
11) Add skb bitfield compaction work related to BPF with the overall goal
to make more of the sk_buff bits optional, from Jakub Kicinski.
12) BPF selftest cleanups for build id extraction which stand on its own
from the upcoming integration work of build id into struct file object,
from Jiri Olsa.
13) Add fixes and optimizations for xsk descriptor validation and several
selftest improvements for xsk sockets, from Kal Conley.
14) Add BPF links for struct_ops and enable switching implementations
of BPF TCP cong-ctls under a given name by replacing backing
struct_ops map, from Kui-Feng Lee.
15) Remove a misleading BPF verifier env->bypass_spec_v1 check on variable
offset stack read as earlier Spectre checks cover this,
from Luis Gerhorst.
16) Fix issues in copy_from_user_nofault() for BPF and other tracers
to resemble copy_from_user_nmi() from safety PoV, from Florian Lehner
and Alexei Starovoitov.
17) Add --json-summary option to test_progs in order for CI tooling to
ease parsing of test results, from Manu Bretelle.
18) Batch of improvements and refactoring to prep for upcoming
bpf_local_storage conversion to bpf_mem_cache_{alloc,free} allocator,
from Martin KaFai Lau.
19) Improve bpftool's visual program dump which produces the control
flow graph in a DOT format by adding C source inline annotations,
from Quentin Monnet.
20) Fix attaching fentry/fexit/fmod_ret/lsm to modules by extracting
the module name from BTF of the target and searching kallsyms of
the correct module, from Viktor Malik.
21) Improve BPF verifier handling of '<const> <cond> <non_const>'
to better detect whether in particular jmp32 branches are taken,
from Yonghong Song.
22) Allow BPF TCP cong-ctls to write app_limited of struct tcp_sock.
A built-in cc or one from a kernel module is already able to write
to app_limited, from Yixin Shen.
Conflicts:
Documentation/bpf/bpf_devel_QA.rst
b7abcd9c65 ("bpf, doc: Link to submitting-patches.rst for general patch submission info")
0f10f647f4 ("bpf, docs: Use internal linking for link to netdev subsystem doc")
https://lore.kernel.org/all/20230307095812.236eb1be@canb.auug.org.au/
include/net/ip_tunnels.h
bc9d003dc4 ("ip_tunnel: Preserve pointer const in ip_tunnel_info_opts")
ac931d4cde ("ipip,ip_tunnel,sit: Add FOU support for externally controlled ipip devices")
https://lore.kernel.org/all/20230413161235.4093777-1-broonie@kernel.org/
net/bpf/test_run.c
e5995bc7e2 ("bpf, test_run: fix crashes due to XDP frame overwriting/corruption")
294635a816 ("bpf, test_run: fix &xdp_frame misplacement for LIVE_FRAMES")
https://lore.kernel.org/all/20230320102619.05b80a98@canb.auug.org.au/
====================
Link: https://lore.kernel.org/r/20230413191525.7295-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Now that bpf_cgroup_acquire() is KF_RCU | KF_RET_NULL,
bpf_cgroup_kptr_get() is redundant. Let's remove it, and update
selftests to instead use bpf_cgroup_acquire() where appropriate. The
next patch will update the BPF documentation to not mention
bpf_cgroup_kptr_get().
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230411041633.179404-2-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
struct cgroup is already an RCU-safe type in the verifier. We can
therefore update bpf_cgroup_acquire() to be KF_RCU | KF_RET_NULL, and
subsequently remove bpf_cgroup_kptr_get(). This patch does the first of
these by updating bpf_cgroup_acquire() to be KF_RCU | KF_RET_NULL, and
also updates selftests accordingly.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230411041633.179404-1-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When tracing a kernel function with arg type is u32*, btf_ctx_access()
would report error: arg2 type INT is not a struct.
The commit bb6728d756 ("bpf: Allow access to int pointer arguments
in tracing programs") added support for int pointer, but did not skip
modifiers before checking it's type. This patch fixes it.
Fixes: bb6728d756 ("bpf: Allow access to int pointer arguments in tracing programs")
Co-developed-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Feng Zhou <zhoufeng.zf@bytedance.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20230410085908.98493-2-zhoufeng.zf@bytedance.com
Drop the log_size>0 and log_buf!=NULL condition when log_level>0. This
allows users to request log_true_size of a full log without providing
actual (even if small) log buffer. Verifier log handling code was mostly
ready to handle NULL log->ubuf, so only few small changes were necessary
to prevent NULL log->ubuf from causing problems.
Note, that if user provided NULL log_buf with log_level>0 we don't
consider this a log truncation, and thus won't return -ENOSPC.
We also enforce that either (log_buf==NULL && log_size==0) or
(log_buf!=NULL && log_size>0).
Suggested-by: Lorenz Bauer <lmb@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Lorenz Bauer <lmb@isovalent.com>
Link: https://lore.kernel.org/bpf/20230406234205.323208-15-andrii@kernel.org
Simplify internal verifier log API down to bpf_vlog_init() and
bpf_vlog_finalize(). The former handles input arguments validation in
one place and makes it easier to change it. The latter subsumes -ENOSPC
(truncation) and -EFAULT handling and simplifies both caller's code
(bpf_check() and btf_parse()).
For btf_parse(), this patch also makes sure that verifier log
finalization happens even if there is some error condition during BTF
verification process prior to normal finalization step.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Lorenz Bauer <lmb@isovalent.com>
Link: https://lore.kernel.org/bpf/20230406234205.323208-14-andrii@kernel.org
Add output-only log_true_size and btf_log_true_size field to
BPF_PROG_LOAD and BPF_BTF_LOAD commands, respectively. It will return
the size of log buffer necessary to fit in all the log contents at
specified log_level. This is very useful for BPF loader libraries like
libbpf to be able to size log buffer correctly, but could be used by
users directly, if necessary, as well.
This patch plumbs all this through the code, taking into account actual
bpf_attr size provided by user to determine if these new fields are
expected by users. And if they are, set them from kernel on return.
We refactory btf_parse() function to accommodate this, moving attr and
uattr handling inside it. The rest is very straightforward code, which
is split from the logging accounting changes in the previous patch to
make it simpler to review logic vs UAPI changes.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Lorenz Bauer <lmb@isovalent.com>
Link: https://lore.kernel.org/bpf/20230406234205.323208-13-andrii@kernel.org
Change how we do accounting in BPF_LOG_FIXED mode and adopt log->end_pos
as *logical* log position. This means that we can go beyond physical log
buffer size now and be able to tell what log buffer size should be to
fit entire log contents without -ENOSPC.
To do this for BPF_LOG_FIXED mode, we need to remove a short-circuiting
logic of not vsnprintf()'ing further log content once we filled up
user-provided buffer, which is done by bpf_verifier_log_needed() checks.
We modify these checks to always keep going if log->level is non-zero
(i.e., log is requested), even if log->ubuf was NULL'ed out due to
copying data to user-space, or if entire log buffer is physically full.
We adopt bpf_verifier_vlog() routine to work correctly with
log->ubuf == NULL condition, performing log formatting into temporary
kernel buffer, doing all the necessary accounting, but just avoiding
copying data out if buffer is full or NULL'ed out.
With these changes, it's now possible to do this sort of determination of
log contents size in both BPF_LOG_FIXED and default rolling log mode.
We need to keep in mind bpf_vlog_reset(), though, which shrinks log
contents after successful verification of a particular code path. This
log reset means that log->end_pos isn't always increasing, so to return
back to users what should be the log buffer size to fit all log content
without causing -ENOSPC even in the presence of log resetting, we need
to keep maximum over "lifetime" of logging. We do this accounting in
bpf_vlog_update_len_max() helper.
A related and subtle aspect is that with this logical log->end_pos even in
BPF_LOG_FIXED mode we could temporary "overflow" buffer, but then reset
it back with bpf_vlog_reset() to a position inside user-supplied
log_buf. In such situation we still want to properly maintain
terminating zero. We will eventually return -ENOSPC even if final log
buffer is small (we detect this through log->len_max check). This
behavior is simpler to reason about and is consistent with current
behavior of verifier log. Handling of this required a small addition to
bpf_vlog_reset() logic to avoid doing put_user() beyond physical log
buffer dimensions.
Another issue to keep in mind is that we limit log buffer size to 32-bit
value and keep such log length as u32, but theoretically verifier could
produce huge log stretching beyond 4GB. Instead of keeping (and later
returning) 64-bit log length, we cap it at UINT_MAX. Current UAPI makes
it impossible to specify log buffer size bigger than 4GB anyways, so we
don't really loose anything here and keep everything consistently 32-bit
in UAPI. This property will be utilized in next patch.
Doing the same determination of maximum log buffer for rolling mode is
trivial, as log->end_pos and log->start_pos are already logical
positions, so there is nothing new there.
These changes do incidentally fix one small issue with previous logging
logic. Previously, if use provided log buffer of size N, and actual log
output was exactly N-1 bytes + terminating \0, kernel logic coun't
distinguish this condition from log truncation scenario which would end
up with truncated log contents of N-1 bytes + terminating \0 as well.
But now with log->end_pos being logical position that could go beyond
actual log buffer size, we can distinguish these two conditions, which
we do in this patch. This plays nicely with returning log_size_actual
(implemented in UAPI in the next patch), as we can now guarantee that if
user takes such log_size_actual and provides log buffer of that exact
size, they will not get -ENOSPC in return.
All in all, all these changes do conceptually unify fixed and rolling
log modes much better, and allow a nice feature requested by users:
knowing what should be the size of the buffer to avoid -ENOSPC.
We'll plumb this through the UAPI and the code in the next patch.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Lorenz Bauer <lmb@isovalent.com>
Link: https://lore.kernel.org/bpf/20230406234205.323208-12-andrii@kernel.org
If verifier log is in BPF_LOG_KERNEL mode, no log->ubuf is expected and
it stays NULL throughout entire verification process. Don't erroneously
return -EFAULT in such case.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Lorenz Bauer <lmb@isovalent.com>
Link: https://lore.kernel.org/bpf/20230406234205.323208-10-andrii@kernel.org
btf_parse() is missing -EFAULT error return if log->ubuf was NULL-ed out
due to error while copying data into user-provided buffer. Add it, but
handle a special case of BPF_LOG_KERNEL in which log->ubuf is always NULL.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Lorenz Bauer <lmb@isovalent.com>
Link: https://lore.kernel.org/bpf/20230406234205.323208-9-andrii@kernel.org
Verifier log position reset is meaningless in BPF_LOG_KERNEL mode, so
just exit early in bpf_vlog_reset() if log->level is BPF_LOG_KERNEL.
This avoid meaningless put_user() into NULL log->ubuf.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Lorenz Bauer <lmb@isovalent.com>
Link: https://lore.kernel.org/bpf/20230406234205.323208-8-andrii@kernel.org
Currently, if user-supplied log buffer to collect BPF verifier log turns
out to be too small to contain full log, bpf() syscall returns -ENOSPC,
fails BPF program verification/load, and preserves first N-1 bytes of
the verifier log (where N is the size of user-supplied buffer).
This is problematic in a bunch of common scenarios, especially when
working with real-world BPF programs that tend to be pretty complex as
far as verification goes and require big log buffers. Typically, it's
when debugging tricky cases at log level 2 (verbose). Also, when BPF program
is successfully validated, log level 2 is the only way to actually see
verifier state progression and all the important details.
Even with log level 1, it's possible to get -ENOSPC even if the final
verifier log fits in log buffer, if there is a code path that's deep
enough to fill up entire log, even if normally it would be reset later
on (there is a logic to chop off successfully validated portions of BPF
verifier log).
In short, it's not always possible to pre-size log buffer. Also, what's
worse, in practice, the end of the log most often is way more important
than the beginning, but verifier stops emitting log as soon as initial
log buffer is filled up.
This patch switches BPF verifier log behavior to effectively behave as
rotating log. That is, if user-supplied log buffer turns out to be too
short, verifier will keep overwriting previously written log,
effectively treating user's log buffer as a ring buffer. -ENOSPC is
still going to be returned at the end, to notify user that log contents
was truncated, but the important last N bytes of the log would be
returned, which might be all that user really needs. This consistent
-ENOSPC behavior, regardless of rotating or fixed log behavior, allows
to prevent backwards compatibility breakage. The only user-visible
change is which portion of verifier log user ends up seeing *if buffer
is too small*. Given contents of verifier log itself is not an ABI,
there is no breakage due to this behavior change. Specialized tools that
rely on specific contents of verifier log in -ENOSPC scenario are
expected to be easily adapted to accommodate old and new behaviors.
Importantly, though, to preserve good user experience and not require
every user-space application to adopt to this new behavior, before
exiting to user-space verifier will rotate log (in place) to make it
start at the very beginning of user buffer as a continuous
zero-terminated string. The contents will be a chopped off N-1 last
bytes of full verifier log, of course.
Given beginning of log is sometimes important as well, we add
BPF_LOG_FIXED (which equals 8) flag to force old behavior, which allows
tools like veristat to request first part of verifier log, if necessary.
BPF_LOG_FIXED flag is also a simple and straightforward way to check if
BPF verifier supports rotating behavior.
On the implementation side, conceptually, it's all simple. We maintain
64-bit logical start and end positions. If we need to truncate the log,
start position will be adjusted accordingly to lag end position by
N bytes. We then use those logical positions to calculate their matching
actual positions in user buffer and handle wrap around the end of the
buffer properly. Finally, right before returning from bpf_check(), we
rotate user log buffer contents in-place as necessary, to make log
contents contiguous. See comments in relevant functions for details.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Lorenz Bauer <lmb@isovalent.com>
Link: https://lore.kernel.org/bpf/20230406234205.323208-4-andrii@kernel.org
It's not clear why we have 128 as minimum size, but it makes testing
harder and seems unnecessary, as we carefully handle truncation
scenarios and use proper snprintf variants. So remove this limitation
and just enforce positive length for log buffer.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Lorenz Bauer <lmb@isovalent.com>
Link: https://lore.kernel.org/bpf/20230406234205.323208-3-andrii@kernel.org
kernel/bpf/verifier.c file is large and growing larger all the time. So
it's good to start splitting off more or less self-contained parts into
separate files to keep source code size (somewhat) somewhat under
control.
This patch is a one step in this direction, moving some of BPF verifier log
routines into a separate kernel/bpf/log.c. Right now it's most low-level
and isolated routines to append data to log, reset log to previous
position, etc. Eventually we could probably move verifier state
printing logic here as well, but this patch doesn't attempt to do that
yet.
Subsequent patches will add more logic to verifier log management, so
having basics in a separate file will make sure verifier.c doesn't grow
more with new changes.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Lorenz Bauer <lmb@isovalent.com>
Link: https://lore.kernel.org/bpf/20230406234205.323208-2-andrii@kernel.org
BPF helpers that take an ARG_PTR_TO_UNINIT_MEM must ensure that all of
the memory is set, including beyond the end of the string.
Signed-off-by: Barret Rhoden <brho@google.com>
Link: https://lore.kernel.org/r/20230407001808.1622968-1-brho@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently, the verifier does not handle '<const> <cond_op> <non_const>' well.
For example,
...
10: (79) r1 = *(u64 *)(r10 -16) ; R1_w=scalar() R10=fp0
11: (b7) r2 = 0 ; R2_w=0
12: (2d) if r2 > r1 goto pc+2
13: (b7) r0 = 0
14: (95) exit
15: (65) if r1 s> 0x1 goto pc+3
16: (0f) r0 += r1
...
At insn 12, verifier decides both true and false branch are possible, but
actually only false branch is possible.
Currently, the verifier already supports patterns '<non_const> <cond_op> <const>.
Add support for patterns '<const> <cond_op> <non_const>' in a similar way.
Also fix selftest 'verifier_bounds_mix_sign_unsign/bounds checks mixing signed and unsigned, variant 10'
due to this change.
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230406164505.1046801-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently, for BPF_JEQ/BPF_JNE insn, verifier determines
whether the branch is taken or not only if both operands
are constants. Therefore, for the following code snippet,
0: (85) call bpf_ktime_get_ns#5 ; R0_w=scalar()
1: (a5) if r0 < 0x3 goto pc+2 ; R0_w=scalar(umin=3)
2: (b7) r2 = 2 ; R2_w=2
3: (1d) if r0 == r2 goto pc+2 6
At insn 3, since r0 is not a constant, verifier assumes both branch
can be taken which may lead inproper verification failure.
Add comparing umin/umax value and the constant. If the umin value
is greater than the constant, or umax value is smaller than the constant,
for JEQ the branch must be not-taken, and for JNE the branch must be taken.
The jmp32 mode JEQ/JNE branch taken checking is also handled similarly.
The following lists the veristat result w.r.t. changed number
of processes insns during verification:
File Program Insns (A) Insns (B) Insns (DIFF)
----------------------------------------------------- ---------------------------------------------------- --------- --------- ---------------
test_cls_redirect.bpf.linked3.o cls_redirect 64980 73472 +8492 (+13.07%)
test_seg6_loop.bpf.linked3.o __add_egr_x 12425 12423 -2 (-0.02%)
test_tcp_hdr_options.bpf.linked3.o estab 2634 2558 -76 (-2.89%)
test_parse_tcp_hdr_opt.bpf.linked3.o xdp_ingress_v6 1421 1420 -1 (-0.07%)
test_parse_tcp_hdr_opt_dynptr.bpf.linked3.o xdp_ingress_v6 1238 1237 -1 (-0.08%)
test_tc_dtime.bpf.linked3.o egress_fwdns_prio100 414 411 -3 (-0.72%)
Mostly a small improvement but test_cls_redirect.bpf.linked3.o has a 13% regression.
I checked with verifier log and found it this is due to pruning.
For some JEQ/JNE branches impacted by this patch,
one branch is explored and the other has state equivalence and
pruned.
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230406164455.1045294-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The commit 6fcd486b3a ("bpf: Refactor RCU enforcement in the verifier.")
broke several tracing bpf programs. Even in clang compiled kernels there are
many fields that are not marked with __rcu that are safe to read and pass into
helpers, but the verifier doesn't know that they're safe. Aggressively marking
them as PTR_UNTRUSTED was premature.
Fixes: 6fcd486b3a ("bpf: Refactor RCU enforcement in the verifier.")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/bpf/20230404045029.82870-8-alexei.starovoitov@gmail.com
check_reg_type() unconditionally disallows PTR_TO_BTF_ID | PTR_MAYBE_NULL.
It's problematic for helpers that allow ARG_PTR_TO_BTF_ID_OR_NULL like
bpf_sk_storage_get(). Allow passing PTR_TO_BTF_ID | PTR_MAYBE_NULL into such
helpers. That technically includes bpf_kptr_xchg() helper, but in practice:
bpf_kptr_xchg(..., bpf_cpumask_create());
is still disallowed because bpf_cpumask_create() returns ref counted pointer
with ref_obj_id > 0.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/bpf/20230404045029.82870-6-alexei.starovoitov@gmail.com
bpf_[sk|inode|task|cgrp]_storage_[get|delete]() and bpf_get_socket_cookie() helpers
perform run-time check that sk|inode|task|cgrp pointer != NULL.
Teach verifier about this fact and allow bpf programs to pass
PTR_TO_BTF_ID | PTR_MAYBE_NULL into such helpers.
It will be used in the subsequent patch that will do
bpf_sk_storage_get(.., skb->sk, ...);
Even when 'skb' pointer is trusted the 'sk' pointer may be NULL.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/bpf/20230404045029.82870-5-alexei.starovoitov@gmail.com
btf_nested_type_is_trusted() tries to find a struct member at corresponding offset.
It works for flat structures and falls apart in more complex structs with nested structs.
The offset->member search is already performed by btf_struct_walk() including nested structs.
Reuse this work and pass {field name, field btf id} into btf_nested_type_is_trusted()
instead of offset to make BTF_TYPE_SAFE*() logic more robust.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/bpf/20230404045029.82870-4-alexei.starovoitov@gmail.com
Remove duplicated if (atype == BPF_READ) btf_struct_access() from
btf_struct_access() callback and invoke it only for writes. This is
possible to do because currently btf_struct_access() custom callback
always delegates to generic btf_struct_access() helper for BPF_READ
accesses.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/bpf/20230404045029.82870-2-alexei.starovoitov@gmail.com
bpf_obj_drop_impl has a void return type. In check_kfunc_call, the "else
if" which sets insn_aux->kptr_struct_meta for bpf_obj_drop_impl is
surrounded by a larger if statement which checks btf_type_is_ptr. As a
result:
* The bpf_obj_drop_impl-specific code will never execute
* The btf_struct_meta input to bpf_obj_drop is always NULL
* __bpf_obj_drop_impl will always see a NULL btf_record when called
from BPF program, and won't call bpf_obj_free_fields
* program-allocated kptrs which have fields that should be cleaned up
by bpf_obj_free_fields may instead leak resources
This patch adds a btf_type_is_void branch to the larger if and moves
special handling for bpf_obj_drop_impl there, fixing the issue.
Fixes: ac9f06050a ("bpf: Introduce bpf_obj_drop")
Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230403200027.2271029-1-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
If the value size in a bloom filter is a multiple of 4, then the jhash2()
function is used to compute hashes. The length parameter of this function
equals to the number of 32-bit words in input. Compute it in the hot path
instead of pre-computing it, as this is translated to one extra shift to
divide the length by four vs. one extra memory load of a pre-computed length.
Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
Link: https://lore.kernel.org/r/20230402114340.3441-1-aspsk@isovalent.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In commit 22df776a9a ("tasks: Extract rcu_users out of union"), the
'refcount_t rcu_users' field was extracted out of a union with the
'struct rcu_head rcu' field. This allows us to safely perform a
refcount_inc_not_zero() on task->rcu_users when acquiring a reference on
a task struct. A prior patch leveraged this by making struct task_struct
an RCU-protected object in the verifier, and by bpf_task_acquire() to
use the task->rcu_users field for synchronization.
Now that we can use RCU to protect tasks, we no longer need
bpf_task_kptr_get(), or bpf_task_acquire_not_zero(). bpf_task_kptr_get()
is truly completely unnecessary, as we can just use RCU to get the
object. bpf_task_acquire_not_zero() is now equivalent to
bpf_task_acquire().
In addition to these changes, this patch also updates the associated
selftests to no longer use these kfuncs.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230331195733.699708-3-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
struct task_struct objects are a bit interesting in terms of how their
lifetime is protected by refcounts. task structs have two refcount
fields:
1. refcount_t usage: Protects the memory backing the task struct. When
this refcount drops to 0, the task is immediately freed, without
waiting for an RCU grace period to elapse. This is the field that
most callers in the kernel currently use to ensure that a task
remains valid while it's being referenced, and is what's currently
tracked with bpf_task_acquire() and bpf_task_release().
2. refcount_t rcu_users: A refcount field which, when it drops to 0,
schedules an RCU callback that drops a reference held on the 'usage'
field above (which is acquired when the task is first created). This
field therefore provides a form of RCU protection on the task by
ensuring that at least one 'usage' refcount will be held until an RCU
grace period has elapsed. The qualifier "a form of" is important
here, as a task can remain valid after task->rcu_users has dropped to
0 and the subsequent RCU gp has elapsed.
In terms of BPF, we want to use task->rcu_users to protect tasks that
function as referenced kptrs, and to allow tasks stored as referenced
kptrs in maps to be accessed with RCU protection.
Let's first determine whether we can safely use task->rcu_users to
protect tasks stored in maps. All of the bpf_task* kfuncs can only be
called from tracepoint, struct_ops, or BPF_PROG_TYPE_SCHED_CLS, program
types. For tracepoint and struct_ops programs, the struct task_struct
passed to a program handler will always be trusted, so it will always be
safe to call bpf_task_acquire() with any task passed to a program.
Note, however, that we must update bpf_task_acquire() to be KF_RET_NULL,
as it is possible that the task has exited by the time the program is
invoked, even if the pointer is still currently valid because the main
kernel holds a task->usage refcount. For BPF_PROG_TYPE_SCHED_CLS, tasks
should never be passed as an argument to the any program handlers, so it
should not be relevant.
The second question is whether it's safe to use RCU to access a task
that was acquired with bpf_task_acquire(), and stored in a map. Because
bpf_task_acquire() now uses task->rcu_users, it follows that if the task
is present in the map, that it must have had at least one
task->rcu_users refcount by the time the current RCU cs was started.
Therefore, it's safe to access that task until the end of the current
RCU cs.
With all that said, this patch makes struct task_struct is an
RCU-protected object. In doing so, we also change bpf_task_acquire() to
be KF_ACQUIRE | KF_RCU | KF_RET_NULL, and adjust any selftests as
necessary. A subsequent patch will remove bpf_task_kptr_get(), and
bpf_task_acquire_not_zero() respectively.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230331195733.699708-2-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When validating a helper function argument, we use check_reg_type() to
ensure that the register containing the argument is of the correct type.
When the register's base type is PTR_TO_BTF_ID, there is some
supplemental logic where we do extra checks for various combinations of
PTR_TO_BTF_ID type modifiers. For example, for PTR_TO_BTF_ID,
PTR_TO_BTF_ID | PTR_TRUSTED, and PTR_TO_BTF_ID | MEM_RCU, we call
map_kptr_match_type() for bpf_kptr_xchg() calls, and
btf_struct_ids_match() for other helper calls.
When an unhandled PTR_TO_BTF_ID type modifier combination is passed to
check_reg_type(), the verifier fails with an internal verifier error
message. This can currently be triggered by passing a PTR_MAYBE_NULL
pointer to helper functions (currently just bpf_kptr_xchg()) with an
ARG_PTR_TO_BTF_ID_OR_NULL arg type. For example, by callin
bpf_kptr_xchg(&v->kptr, bpf_cpumask_create()).
Whether or not passing a PTR_MAYBE_NULL arg to an
ARG_PTR_TO_BTF_ID_OR_NULL argument is valid is an interesting question.
In a vacuum, it seems fine. A helper function with an
ARG_PTR_TO_BTF_ID_OR_NULL arg would seem to be implying that it can
handle either a NULL or non-NULL arg, and has logic in place to detect
and gracefully handle each. This is the case for bpf_kptr_xchg(), which
of course simply does an xchg(). On the other hand, bpf_kptr_xchg() also
specifies OBJ_RELEASE, and refcounting semantics for a PTR_MAYBE_NULL
pointer is different than handling it for a NULL _OR_ non-NULL pointer.
For example, with a non-NULL arg, we should always fail if there was not
a nonzero refcount for the value in the register being passed to the
helper. For PTR_MAYBE_NULL on the other hand, it's unclear. If the
pointer is NULL it would be fine, but if it's not NULL, it would be
incorrect to load the program.
The current solution to this is to just fail if PTR_MAYBE_NULL is
passed, and to instead require programs to have a NULL check to
explicitly handle the NULL and non-NULL cases. This seems reasonable.
Not only would it possibly be quite complicated to correctly handle
PTR_MAYBE_NULL refcounting in the verifier, but it's also an arguably
odd programming pattern in general to not explicitly handle the NULL
case anyways. For example, it seems odd to not care about whether a
pointer you're passing to bpf_kptr_xchg() was successfully allocated in
a program such as the following:
private(MASK) static struct bpf_cpumask __kptr * global_mask;
SEC("tp_btf/task_newtask")
int BPF_PROG(example, struct task_struct *task, u64 clone_flags)
{
struct bpf_cpumask *prev;
/* bpf_cpumask_create() returns PTR_MAYBE_NULL */
prev = bpf_kptr_xchg(&global_mask, bpf_cpumask_create());
if (prev)
bpf_cpumask_release(prev);
return 0;
}
This patch therefore updates the verifier to explicitly check for
PTR_MAYBE_NULL in check_reg_type(), and fail gracefully if it's
observed. This isn't really "fixing" anything unsafe or incorrect. We're
just updating the verifier to fail gracefully, and explicitly handle
this pattern rather than unintentionally falling back to an internal
verifier error path. A subsequent patch will update selftests.
Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230330145203.80506-1-void@manifault.com
This patch uses bpf_mem_cache_alloc/free for allocating and freeing
bpf_local_storage for task and cgroup storage.
The changes are similar to the previous patch. A few things that
worth to mention for bpf_local_storage:
The local_storage is freed when the last selem is deleted.
Before deleting a selem from local_storage, it needs to retrieve the
local_storage->smap because the bpf_selem_unlink_storage_nolock()
may have set it to NULL. Note that local_storage->smap may have
already been NULL when the selem created this local_storage has
been removed. In this case, call_rcu will be used to free the
local_storage.
Also, the bpf_ma (true or false) value is needed before calling
bpf_local_storage_free(). The bpf_ma can either be obtained from
the local_storage->smap (if available) or any of its selem's smap.
A new helper check_storage_bpf_ma() is added to obtain
bpf_ma for a deleting bpf_local_storage.
When bpf_local_storage_alloc getting a reused memory, all
fields are either in the correct values or will be initialized.
'cache[]' must already be all NULLs. 'list' must be empty.
Others will be initialized.
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20230322215246.1675516-4-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch uses bpf_mem_alloc for the task and cgroup local storage that
the bpf prog can easily get a hold of the storage owner's PTR_TO_BTF_ID.
eg. bpf_get_current_task_btf() can be used in some of the kmalloc code
path which will cause deadlock/recursion. bpf_mem_cache_alloc is
deadlock free and will solve a legit use case in [1].
For sk storage, its batch creation benchmark shows a few percent
regression when the sk create/destroy batch size is larger than 32.
The sk creation/destruction happens much more often and
depends on external traffic. Considering it is hypothetical
to be able to cause deadlock with sk storage, it can cross
the bridge to use bpf_mem_alloc till a legit (ie. useful)
use case comes up.
For inode storage, bpf_local_storage_destroy() is called before
waiting for a rcu gp and its memory cannot be reused immediately.
inode stays with kmalloc/kfree after the rcu [or tasks_trace] gp.
A 'bool bpf_ma' argument is added to bpf_local_storage_map_alloc().
Only task and cgroup storage have 'bpf_ma == true' which
means to use bpf_mem_cache_alloc/free(). This patch only changes
selem to use bpf_mem_alloc for task and cgroup. The next patch
will change the local_storage to use bpf_mem_alloc also for
task and cgroup.
Here is some more details on the changes:
* memory allocation:
After bpf_mem_cache_alloc(), the SDATA(selem)->data is zero-ed because
bpf_mem_cache_alloc() could return a reused selem. It is to keep
the existing bpf_map_kzalloc() behavior. Only SDATA(selem)->data
is zero-ed. SDATA(selem)->data is the visible part to the bpf prog.
No need to use zero_map_value() to do the zeroing because
bpf_selem_free(..., reuse_now = true) ensures no bpf prog is using
the selem before returning the selem through bpf_mem_cache_free().
For the internal fields of selem, they will be initialized when
linking to the new smap and the new local_storage.
When 'bpf_ma == false', nothing changes in this patch. It will
stay with the bpf_map_kzalloc().
* memory free:
The bpf_selem_free() and bpf_selem_free_rcu() are modified to handle
the bpf_ma == true case.
For the common selem free path where its owner is also being destroyed,
the mem is freed in bpf_local_storage_destroy(), the owner (task
and cgroup) has gone through a rcu gp. The memory can be reused
immediately, so bpf_local_storage_destroy() will call
bpf_selem_free(..., reuse_now = true) which will do
bpf_mem_cache_free() for immediate reuse consideration.
An exception is the delete elem code path. The delete elem code path
is called from the helper bpf_*_storage_delete() and the syscall
bpf_map_delete_elem(). This path is an unusual case for local
storage because the common use case is to have the local storage
staying with its owner life time so that the bpf prog and the user
space does not have to monitor the owner's destruction. For the delete
elem path, the selem cannot be reused immediately because there could
be bpf prog using it. It will call bpf_selem_free(..., reuse_now = false)
and it will wait for a rcu tasks trace gp before freeing the elem. The
rcu callback is changed to do bpf_mem_cache_raw_free() instead of kfree().
When 'bpf_ma == false', it should be the same as before.
__bpf_selem_free() is added to do the kfree_rcu and call_tasks_trace_rcu().
A few words on the 'reuse_now == true'. When 'reuse_now == true',
it is still racing with bpf_local_storage_map_free which is under rcu
protection, so it still needs to wait for a rcu gp instead of kfree().
Otherwise, the selem may be reused by slab for a totally different struct
while the bpf_local_storage_map_free() is still using it (as a
rcu reader). For the inode case, there may be other rcu readers also.
In short, when bpf_ma == false and reuse_now == true => vanilla rcu.
[1]: https://lore.kernel.org/bpf/20221118190109.1512674-1-namhyung@kernel.org/
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20230322215246.1675516-3-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch adds a few bpf mem allocator functions which will
be used in the bpf_local_storage in a later patch.
bpf_mem_cache_alloc_flags(..., gfp_t flags) is added. When the
flags == GFP_KERNEL, it will fallback to __alloc(..., GFP_KERNEL).
bpf_local_storage knows its running context is sleepable (GFP_KERNEL)
and provides a better guarantee on memory allocation.
bpf_local_storage has some uncommon cases that its selem
cannot be reused immediately. It handles its own
rcu_head and goes through a rcu_trace gp and then free it.
bpf_mem_cache_raw_free() is added for direct free purpose
without leaking the LLIST_NODE_SZ internal knowledge.
During free time, the 'struct bpf_mem_alloc *ma' is no longer
available. However, the caller should know if it is
percpu memory or not and it can call different raw_free functions.
bpf_local_storage does not support percpu value, so only
the non-percpu 'bpf_mem_cache_raw_free()' is added in
this patch.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20230322215246.1675516-2-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
KF_RELEASE kfuncs are not currently treated as having KF_TRUSTED_ARGS,
even though they have a superset of the requirements of KF_TRUSTED_ARGS.
Like KF_TRUSTED_ARGS, KF_RELEASE kfuncs require a 0-offset argument, and
don't allow NULL-able arguments. Unlike KF_TRUSTED_ARGS which require
_either_ an argument with ref_obj_id > 0, _or_ (ref->type &
BPF_REG_TRUSTED_MODIFIERS) (and no unsafe modifiers allowed), KF_RELEASE
only allows for ref_obj_id > 0. Because KF_RELEASE today doesn't
automatically imply KF_TRUSTED_ARGS, some of these requirements are
enforced in different ways that can make the behavior of the verifier
feel unpredictable. For example, a KF_RELEASE kfunc with a NULL-able
argument will currently fail in the verifier with a message like, "arg#0
is ptr_or_null_ expected ptr_ or socket" rather than "Possibly NULL
pointer passed to trusted arg0". Our intention is the same, but the
semantics are different due to implemenetation details that kfunc authors
and BPF program writers should not need to care about.
Let's make the behavior of the verifier more consistent and intuitive by
having KF_RELEASE kfuncs imply the presence of KF_TRUSTED_ARGS. Our
eventual goal is to have all kfuncs assume KF_TRUSTED_ARGS by default
anyways, so this takes us a step in that direction.
Note that it does not make sense to assume KF_TRUSTED_ARGS for all
KF_ACQUIRE kfuncs. KF_ACQUIRE kfuncs can have looser semantics than
KF_RELEASE, with e.g. KF_RCU | KF_RET_NULL. We may want to have
KF_ACQUIRE imply KF_TRUSTED_ARGS _unless_ KF_RCU is specified, but that
can be left to another patch set, and there are no such subtleties to
address for KF_RELEASE.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230325213144.486885-4-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Now that we're not invoking kfunc destructors when the kptr in a map was
NULL, we no longer require NULL checks in many of our KF_RELEASE kfuncs.
This patch removes those NULL checks.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230325213144.486885-3-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When a map value is being freed, we loop over all of the fields of the
corresponding BPF object and issue the appropriate cleanup calls
corresponding to the field's type. If the field is a referenced kptr, we
atomically xchg the value out of the map, and invoke the kptr's
destructor on whatever was there before (or bpf_obj_drop() it if it was
a local kptr).
Currently, we always invoke the destructor (either bpf_obj_drop() or the
kptr's registered destructor) on any KPTR_REF-type field in a map, even
if there wasn't a value in the map. This means that any function serving
as the kptr's KF_RELEASE destructor must always treat the argument as
possibly NULL, as the following can and regularly does happen:
void *xchgd_field;
/* No value was in the map, so xchgd_field is NULL */
xchgd_field = (void *)xchg(unsigned long *field_ptr, 0);
field->kptr.dtor(xchgd_field);
These are odd semantics to impose on KF_RELEASE kfuncs -- BPF programs
are prohibited by the verifier from passing NULL pointers to KF_RELEASE
kfuncs, so it doesn't make sense to require this of BPF programs, but
not the main kernel destructor path. It's also unnecessary to invoke any
cleanup logic for local kptrs. If there is no object there, there's
nothing to drop.
So as to allow KF_RELEASE kfuncs to fully assume that an argument is
non-NULL, this patch updates a KPTR_REF's destructor to only be invoked
when a non-NULL value is xchg'd out of the kptr map field.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230325213144.486885-2-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch fixes a mistake in checking NULL instead of
checking IS_ERR for the bpf_map_get() return value.
It also fixes the return value in link_update_map() from -EINVAL
to PTR_ERR(*_map).
Reported-by: syzbot+71ccc0fe37abb458406b@syzkaller.appspotmail.com
Fixes: 68b04864ca ("bpf: Create links for BPF struct_ops maps.")
Fixes: aef56f2e91 ("bpf: Update the struct_ops of a bpf_link.")
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: Kui-Feng Lee <kuifeng@meta.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230324184241.1387437-1-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
By improving the BPF_LINK_UPDATE command of bpf(), it should allow you
to conveniently switch between different struct_ops on a single
bpf_link. This would enable smoother transitions from one struct_ops
to another.
The struct_ops maps passing along with BPF_LINK_UPDATE should have the
BPF_F_LINK flag.
Signed-off-by: Kui-Feng Lee <kuifeng@meta.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230323032405.3735486-6-kuifeng@meta.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Make bpf_link support struct_ops. Previously, struct_ops were always
used alone without any associated links. Upon updating its value, a
struct_ops would be activated automatically. Yet other BPF program
types required to make a bpf_link with their instances before they
could become active. Now, however, you can create an inactive
struct_ops, and create a link to activate it later.
With bpf_links, struct_ops has a behavior similar to other BPF program
types. You can pin/unpin them from their links and the struct_ops will
be deactivated when its link is removed while previously need someone
to delete the value for it to be deactivated.
bpf_links are responsible for registering their associated
struct_ops. You can only use a struct_ops that has the BPF_F_LINK flag
set to create a bpf_link, while a structs without this flag behaves in
the same manner as before and is registered upon updating its value.
The BPF_LINK_TYPE_STRUCT_OPS serves a dual purpose. Not only is it
used to craft the links for BPF struct_ops programs, but also to
create links for BPF struct_ops them-self. Since the links of BPF
struct_ops programs are only used to create trampolines internally,
they are never seen in other contexts. Thus, they can be reused for
struct_ops themself.
To maintain a reference to the map supporting this link, we add
bpf_struct_ops_link as an additional type. The pointer of the map is
RCU and won't be necessary until later in the patchset.
Signed-off-by: Kui-Feng Lee <kuifeng@meta.com>
Link: https://lore.kernel.org/r/20230323032405.3735486-4-kuifeng@meta.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
We have replaced kvalue-refcnt with synchronize_rcu() to wait for an
RCU grace period.
Maintenance of kvalue->refcnt was a complicated task, as we had to
simultaneously keep track of two reference counts: one for the
reference count of bpf_map. When the kvalue->refcnt reaches zero, we
also have to reduce the reference count on bpf_map - yet these steps
are not performed in an atomic manner and require us to be vigilant
when managing them. By eliminating kvalue->refcnt, we can make our
maintenance more straightforward as the refcount of bpf_map is now
solely managed!
To prevent the trampoline image of a struct_ops from being released
while it is still in use, we wait for an RCU grace period. The
setsockopt(TCP_CONGESTION, "...") command allows you to change your
socket's congestion control algorithm and can result in releasing the
old struct_ops implementation. It is fine. However, this function is
exposed through bpf_setsockopt(), it may be accessed by BPF programs
as well. To ensure that the trampoline image belonging to struct_op
can be safely called while its method is in use, the trampoline
safeguarde the BPF program with rcu_read_lock(). Doing so prevents any
destruction of the associated images before returning from a
trampoline and requires us to wait for an RCU grace period.
Signed-off-by: Kui-Feng Lee <kuifeng@meta.com>
Link: https://lore.kernel.org/r/20230323032405.3735486-2-kuifeng@meta.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
For iter_new() functions iterator state's slot might not be yet
initialized, in which case iter_get_spi() will return -ERANGE. This is
expected and is handled properly. But for iter_next() and iter_destroy()
cases iter slot is supposed to be initialized and correct, so -ERANGE is
not possible.
Move meta->iter.{spi,frameno} initialization into iter_next/iter_destroy
handling branch to make it more explicit that valid information will be
remembered in meta->iter block for subsequent use in process_iter_next_call(),
avoiding confusingly looking -ERANGE assignment for meta->iter.spi.
Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230322232502.836171-1-andrii@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Xu reports that after commit 3f50f132d8 ("bpf: Verifier, do explicit ALU32
bounds tracking"), the following BPF program is rejected by the verifier:
0: (61) r2 = *(u32 *)(r1 +0) ; R2_w=pkt(off=0,r=0,imm=0)
1: (61) r3 = *(u32 *)(r1 +4) ; R3_w=pkt_end(off=0,imm=0)
2: (bf) r1 = r2
3: (07) r1 += 1
4: (2d) if r1 > r3 goto pc+8
5: (71) r1 = *(u8 *)(r2 +0) ; R1_w=scalar(umax=255,var_off=(0x0; 0xff))
6: (18) r0 = 0x7fffffffffffff10
8: (0f) r1 += r0 ; R1_w=scalar(umin=0x7fffffffffffff10,umax=0x800000000000000f)
9: (18) r0 = 0x8000000000000000
11: (07) r0 += 1
12: (ad) if r0 < r1 goto pc-2
13: (b7) r0 = 0
14: (95) exit
And the verifier log says:
func#0 @0
0: R1=ctx(off=0,imm=0) R10=fp0
0: (61) r2 = *(u32 *)(r1 +0) ; R1=ctx(off=0,imm=0) R2_w=pkt(off=0,r=0,imm=0)
1: (61) r3 = *(u32 *)(r1 +4) ; R1=ctx(off=0,imm=0) R3_w=pkt_end(off=0,imm=0)
2: (bf) r1 = r2 ; R1_w=pkt(off=0,r=0,imm=0) R2_w=pkt(off=0,r=0,imm=0)
3: (07) r1 += 1 ; R1_w=pkt(off=1,r=0,imm=0)
4: (2d) if r1 > r3 goto pc+8 ; R1_w=pkt(off=1,r=1,imm=0) R3_w=pkt_end(off=0,imm=0)
5: (71) r1 = *(u8 *)(r2 +0) ; R1_w=scalar(umax=255,var_off=(0x0; 0xff)) R2_w=pkt(off=0,r=1,imm=0)
6: (18) r0 = 0x7fffffffffffff10 ; R0_w=9223372036854775568
8: (0f) r1 += r0 ; R0_w=9223372036854775568 R1_w=scalar(umin=9223372036854775568,umax=9223372036854775823,s32_min=-240,s32_max=15)
9: (18) r0 = 0x8000000000000000 ; R0_w=-9223372036854775808
11: (07) r0 += 1 ; R0_w=-9223372036854775807
12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775807 R1_w=scalar(umin=9223372036854775568,umax=9223372036854775809)
13: (b7) r0 = 0 ; R0_w=0
14: (95) exit
from 12 to 11: R0_w=-9223372036854775807 R1_w=scalar(umin=9223372036854775810,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff)) R2_w=pkt(off=0,r=1,imm=0) R3_w=pkt_end(off=0,imm=0) R10=fp0
11: (07) r0 += 1 ; R0_w=-9223372036854775806
12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775806 R1_w=scalar(umin=9223372036854775810,umax=9223372036854775810,var_off=(0x8000000000000000; 0xffffffff))
13: safe
[...]
from 12 to 11: R0_w=-9223372036854775795 R1=scalar(umin=9223372036854775822,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff)) R2=pkt(off=0,r=1,imm=0) R3=pkt_end(off=0,imm=0) R10=fp0
11: (07) r0 += 1 ; R0_w=-9223372036854775794
12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775794 R1=scalar(umin=9223372036854775822,umax=9223372036854775822,var_off=(0x8000000000000000; 0xffffffff))
13: safe
from 12 to 11: R0_w=-9223372036854775794 R1=scalar(umin=9223372036854775823,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff)) R2=pkt(off=0,r=1,imm=0) R3=pkt_end(off=0,imm=0) R10=fp0
11: (07) r0 += 1 ; R0_w=-9223372036854775793
12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775793 R1=scalar(umin=9223372036854775823,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff))
13: safe
from 12 to 11: R0_w=-9223372036854775793 R1=scalar(umin=9223372036854775824,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff)) R2=pkt(off=0,r=1,imm=0) R3=pkt_end(off=0,imm=0) R10=fp0
11: (07) r0 += 1 ; R0_w=-9223372036854775792
12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775792 R1=scalar(umin=9223372036854775824,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff))
13: safe
[...]
The 64bit umin=9223372036854775810 bound continuously bumps by +1 while
umax=9223372036854775823 stays as-is until the verifier complexity limit
is reached and the program gets finally rejected. During this simulation,
the umin also eventually surpasses umax. Looking at the first 'from 12
to 11' output line from the loop, R1 has the following state:
R1_w=scalar(umin=0x8000000000000002 (9223372036854775810),
umax=0x800000000000000f (9223372036854775823),
var_off=(0x8000000000000000;
0xffffffff))
The var_off has technically not an inconsistent state but it's very
imprecise and far off surpassing 64bit umax bounds whereas the expected
output with refined known bits in var_off should have been like:
R1_w=scalar(umin=0x8000000000000002 (9223372036854775810),
umax=0x800000000000000f (9223372036854775823),
var_off=(0x8000000000000000;
0xf))
In the above log, var_off stays as var_off=(0x8000000000000000; 0xffffffff)
and does not converge into a narrower mask where more bits become known,
eventually transforming R1 into a constant upon umin=9223372036854775823,
umax=9223372036854775823 case where the verifier would have terminated and
let the program pass.
The __reg_combine_64_into_32() marks the subregister unknown and propagates
64bit {s,u}min/{s,u}max bounds to their 32bit equivalents iff they are within
the 32bit universe. The question came up whether __reg_combine_64_into_32()
should special case the situation that when 64bit {s,u}min bounds have
the same value as 64bit {s,u}max bounds to then assign the latter as
well to the 32bit reg->{s,u}32_{min,max}_value. As can be seen from the
above example however, that is just /one/ special case and not a /generic/
solution given above example would still not be addressed this way and
remain at an imprecise var_off=(0x8000000000000000; 0xffffffff).
The improvement is needed in __reg_bound_offset() to refine var32_off with
the updated var64_off instead of the prior reg->var_off. The reg_bounds_sync()
code first refines information about the register's min/max bounds via
__update_reg_bounds() from the current var_off, then in __reg_deduce_bounds()
from sign bit and with the potentially learned bits from bounds it'll
update the var_off tnum in __reg_bound_offset(). For example, intersecting
with the old var_off might have improved bounds slightly, e.g. if umax
was 0x7f...f and var_off was (0; 0xf...fc), then new var_off will then
result in (0; 0x7f...fc). The intersected var64_off holds then the
universe which is a superset of var32_off. The point for the latter is
not to broaden, but to further refine known bits based on the intersection
of var_off with 32 bit bounds, so that we later construct the final var_off
from upper and lower 32 bits. The final __update_reg_bounds() can then
potentially still slightly refine bounds if more bits became known from the
new var_off.
After the improvement, we can see R1 converging successively:
func#0 @0
0: R1=ctx(off=0,imm=0) R10=fp0
0: (61) r2 = *(u32 *)(r1 +0) ; R1=ctx(off=0,imm=0) R2_w=pkt(off=0,r=0,imm=0)
1: (61) r3 = *(u32 *)(r1 +4) ; R1=ctx(off=0,imm=0) R3_w=pkt_end(off=0,imm=0)
2: (bf) r1 = r2 ; R1_w=pkt(off=0,r=0,imm=0) R2_w=pkt(off=0,r=0,imm=0)
3: (07) r1 += 1 ; R1_w=pkt(off=1,r=0,imm=0)
4: (2d) if r1 > r3 goto pc+8 ; R1_w=pkt(off=1,r=1,imm=0) R3_w=pkt_end(off=0,imm=0)
5: (71) r1 = *(u8 *)(r2 +0) ; R1_w=scalar(umax=255,var_off=(0x0; 0xff)) R2_w=pkt(off=0,r=1,imm=0)
6: (18) r0 = 0x7fffffffffffff10 ; R0_w=9223372036854775568
8: (0f) r1 += r0 ; R0_w=9223372036854775568 R1_w=scalar(umin=9223372036854775568,umax=9223372036854775823,s32_min=-240,s32_max=15)
9: (18) r0 = 0x8000000000000000 ; R0_w=-9223372036854775808
11: (07) r0 += 1 ; R0_w=-9223372036854775807
12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775807 R1_w=scalar(umin=9223372036854775568,umax=9223372036854775809)
13: (b7) r0 = 0 ; R0_w=0
14: (95) exit
from 12 to 11: R0_w=-9223372036854775807 R1_w=scalar(umin=9223372036854775810,umax=9223372036854775823,var_off=(0x8000000000000000; 0xf),s32_min=0,s32_max=15,u32_max=15) R2_w=pkt(off=0,r=1,imm=0) R3_w=pkt_end(off=0,imm=0) R10=fp0
11: (07) r0 += 1 ; R0_w=-9223372036854775806
12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775806 R1_w=-9223372036854775806
13: safe
from 12 to 11: R0_w=-9223372036854775806 R1_w=scalar(umin=9223372036854775811,umax=9223372036854775823,var_off=(0x8000000000000000; 0xf),s32_min=0,s32_max=15,u32_max=15) R2_w=pkt(off=0,r=1,imm=0) R3_w=pkt_end(off=0,imm=0) R10=fp0
11: (07) r0 += 1 ; R0_w=-9223372036854775805
12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775805 R1_w=-9223372036854775805
13: safe
[...]
from 12 to 11: R0_w=-9223372036854775798 R1=scalar(umin=9223372036854775819,umax=9223372036854775823,var_off=(0x8000000000000008; 0x7),s32_min=8,s32_max=15,u32_min=8,u32_max=15) R2=pkt(off=0,r=1,imm=0) R3=pkt_end(off=0,imm=0) R10=fp0
11: (07) r0 += 1 ; R0_w=-9223372036854775797
12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775797 R1=-9223372036854775797
13: safe
from 12 to 11: R0_w=-9223372036854775797 R1=scalar(umin=9223372036854775820,umax=9223372036854775823,var_off=(0x800000000000000c; 0x3),s32_min=12,s32_max=15,u32_min=12,u32_max=15) R2=pkt(off=0,r=1,imm=0) R3=pkt_end(off=0,imm=0) R10=fp0
11: (07) r0 += 1 ; R0_w=-9223372036854775796
12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775796 R1=-9223372036854775796
13: safe
from 12 to 11: R0_w=-9223372036854775796 R1=scalar(umin=9223372036854775821,umax=9223372036854775823,var_off=(0x800000000000000c; 0x3),s32_min=12,s32_max=15,u32_min=12,u32_max=15) R2=pkt(off=0,r=1,imm=0) R3=pkt_end(off=0,imm=0) R10=fp0
11: (07) r0 += 1 ; R0_w=-9223372036854775795
12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775795 R1=-9223372036854775795
13: safe
from 12 to 11: R0_w=-9223372036854775795 R1=scalar(umin=9223372036854775822,umax=9223372036854775823,var_off=(0x800000000000000e; 0x1),s32_min=14,s32_max=15,u32_min=14,u32_max=15) R2=pkt(off=0,r=1,imm=0) R3=pkt_end(off=0,imm=0) R10=fp0
11: (07) r0 += 1 ; R0_w=-9223372036854775794
12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775794 R1=-9223372036854775794
13: safe
from 12 to 11: R0_w=-9223372036854775794 R1=-9223372036854775793 R2=pkt(off=0,r=1,imm=0) R3=pkt_end(off=0,imm=0) R10=fp0
11: (07) r0 += 1 ; R0_w=-9223372036854775793
12: (ad) if r0 < r1 goto pc-2
last_idx 12 first_idx 12
parent didn't have regs=1 stack=0 marks: R0_rw=P-9223372036854775801 R1_r=scalar(umin=9223372036854775815,umax=9223372036854775823,var_off=(0x8000000000000000; 0xf),s32_min=0,s32_max=15,u32_max=15) R2=pkt(off=0,r=1,imm=0) R3=pkt_end(off=0,imm=0) R10=fp0
last_idx 11 first_idx 11
regs=1 stack=0 before 11: (07) r0 += 1
parent didn't have regs=1 stack=0 marks: R0_rw=P-9223372036854775805 R1_rw=scalar(umin=9223372036854775812,umax=9223372036854775823,var_off=(0x8000000000000000; 0xf),s32_min=0,s32_max=15,u32_max=15) R2_w=pkt(off=0,r=1,imm=0) R3_w=pkt_end(off=0,imm=0) R10=fp0
last_idx 12 first_idx 0
regs=1 stack=0 before 12: (ad) if r0 < r1 goto pc-2
regs=1 stack=0 before 11: (07) r0 += 1
regs=1 stack=0 before 12: (ad) if r0 < r1 goto pc-2
regs=1 stack=0 before 11: (07) r0 += 1
regs=1 stack=0 before 12: (ad) if r0 < r1 goto pc-2
regs=1 stack=0 before 11: (07) r0 += 1
regs=1 stack=0 before 9: (18) r0 = 0x8000000000000000
last_idx 12 first_idx 12
parent didn't have regs=2 stack=0 marks: R0_rw=P-9223372036854775801 R1_r=Pscalar(umin=9223372036854775815,umax=9223372036854775823,var_off=(0x8000000000000000; 0xf),s32_min=0,s32_max=15,u32_max=15) R2=pkt(off=0,r=1,imm=0) R3=pkt_end(off=0,imm=0) R10=fp0
last_idx 11 first_idx 11
regs=2 stack=0 before 11: (07) r0 += 1
parent didn't have regs=2 stack=0 marks: R0_rw=P-9223372036854775805 R1_rw=Pscalar(umin=9223372036854775812,umax=9223372036854775823,var_off=(0x8000000000000000; 0xf),s32_min=0,s32_max=15,u32_max=15) R2_w=pkt(off=0,r=1,imm=0) R3_w=pkt_end(off=0,imm=0) R10=fp0
last_idx 12 first_idx 0
regs=2 stack=0 before 12: (ad) if r0 < r1 goto pc-2
regs=2 stack=0 before 11: (07) r0 += 1
regs=2 stack=0 before 12: (ad) if r0 < r1 goto pc-2
regs=2 stack=0 before 11: (07) r0 += 1
regs=2 stack=0 before 12: (ad) if r0 < r1 goto pc-2
regs=2 stack=0 before 11: (07) r0 += 1
regs=2 stack=0 before 9: (18) r0 = 0x8000000000000000
regs=2 stack=0 before 8: (0f) r1 += r0
regs=3 stack=0 before 6: (18) r0 = 0x7fffffffffffff10
regs=2 stack=0 before 5: (71) r1 = *(u8 *)(r2 +0)
13: safe
from 4 to 13: safe
verification time 322 usec
stack depth 0
processed 56 insns (limit 1000000) max_states_per_insn 1 total_states 3 peak_states 3 mark_read 1
This also fixes up a test case along with this improvement where we match
on the verifier log. The updated log now has a refined var_off, too.
Fixes: 3f50f132d8 ("bpf: Verifier, do explicit ALU32 bounds tracking")
Reported-by: Xu Kuohai <xukuohai@huaweicloud.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20230314203424.4015351-2-xukuohai@huaweicloud.com
Link: https://lore.kernel.org/bpf/20230322213056.2470-1-daniel@iogearbox.net
This patch changes the return types of bpf_map_ops functions to long, where
previously int was returned. Using long allows for bpf programs to maintain
the sign bit in the absence of sign extension during situations where
inlined bpf helper funcs make calls to the bpf_map_ops funcs and a negative
error is returned.
The definitions of the helper funcs are generated from comments in the bpf
uapi header at `include/uapi/linux/bpf.h`. The return type of these
helpers was previously changed from int to long in commit bdb7b79b4c. For
any case where one of the map helpers call the bpf_map_ops funcs that are
still returning 32-bit int, a compiler might not include sign extension
instructions to properly convert the 32-bit negative value a 64-bit
negative value.
For example:
bpf assembly excerpt of an inlined helper calling a kernel function and
checking for a specific error:
; err = bpf_map_update_elem(&mymap, &key, &val, BPF_NOEXIST);
...
46: call 0xffffffffe103291c ; htab_map_update_elem
; if (err && err != -EEXIST) {
4b: cmp $0xffffffffffffffef,%rax ; cmp -EEXIST,%rax
kernel function assembly excerpt of return value from
`htab_map_update_elem` returning 32-bit int:
movl $0xffffffef, %r9d
...
movl %r9d, %eax
...results in the comparison:
cmp $0xffffffffffffffef, $0x00000000ffffffef
Fixes: bdb7b79b4c ("bpf: Switch most helper return values from 32-bit int to 64-bit long")
Tested-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
Link: https://lore.kernel.org/r/20230322194754.185781-3-inwardvessel@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Teach the verifier to recognize PTR_TO_MEM | MEM_RDONLY as not NULL
otherwise if (!bpf_ksym_exists(known_kfunc)) doesn't go through
dead code elimination.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/bpf/20230321203854.3035-3-alexei.starovoitov@gmail.com
We've seen recent AWS EKS (Kubernetes) user reports like the following:
After upgrading EKS nodes from v20230203 to v20230217 on our 1.24 EKS
clusters after a few days a number of the nodes have containers stuck
in ContainerCreating state or liveness/readiness probes reporting the
following error:
Readiness probe errored: rpc error: code = Unknown desc = failed to
exec in container: failed to start exec "4a11039f730203ffc003b7[...]":
OCI runtime exec failed: exec failed: unable to start container process:
unable to init seccomp: error loading seccomp filter into kernel:
error loading seccomp filter: errno 524: unknown
However, we had not been seeing this issue on previous AMIs and it only
started to occur on v20230217 (following the upgrade from kernel 5.4 to
5.10) with no other changes to the underlying cluster or workloads.
We tried the suggestions from that issue (sysctl net.core.bpf_jit_limit=452534528)
which helped to immediately allow containers to be created and probes to
execute but after approximately a day the issue returned and the value
returned by cat /proc/vmallocinfo | grep bpf_jit | awk '{s+=$2} END {print s}'
was steadily increasing.
I tested bpf tree to observe bpf_jit_charge_modmem, bpf_jit_uncharge_modmem
their sizes passed in as well as bpf_jit_current under tcpdump BPF filter,
seccomp BPF and native (e)BPF programs, and the behavior all looks sane
and expected, that is nothing "leaking" from an upstream perspective.
The bpf_jit_limit knob was originally added in order to avoid a situation
where unprivileged applications loading BPF programs (e.g. seccomp BPF
policies) consuming all the module memory space via BPF JIT such that loading
of kernel modules would be prevented. The default limit was defined back in
2018 and while good enough back then, we are generally seeing far more BPF
consumers today.
Adjust the limit for the BPF JIT pool from originally 1/4 to now 1/2 of the
module memory space to better reflect today's needs and avoid more users
running into potentially hard to debug issues.
Fixes: fdadd04931 ("bpf: fix bpf_jit_limit knob for PAGE_SIZE >= 64K")
Reported-by: Stephen Haynes <sh@synk.net>
Reported-by: Lefteris Alexakis <lefteris.alexakis@kpn.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://github.com/awslabs/amazon-eks-ami/issues/1179
Link: https://github.com/awslabs/amazon-eks-ami/issues/1219
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20230320143725.8394-1-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Now that the original _ftrace_direct APIs are gone, the "_multi"
suffixes only add confusion.
Link: https://lkml.kernel.org/r/20230321140424.345218-5-revest@chromium.org
Signed-off-by: Florent Revest <revest@chromium.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
A common pattern when using the ftrace_direct_multi API is to unregister
the ops and also immediately free its filter. We've noticed it's very
easy for users to miss calling ftrace_free_filter().
This adds a "free_filters" argument to unregister_ftrace_direct_multi()
to both remind the user they should free filters and also to make their
life easier.
Link: https://lkml.kernel.org/r/20230321140424.345218-2-revest@chromium.org
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Florent Revest <revest@chromium.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Allow ld_imm64 insn with BPF_PSEUDO_BTF_ID to hold the address of kfunc. The
ld_imm64 pointing to a valid kfunc will be seen as non-null PTR_TO_MEM by
is_branch_taken() logic of the verifier, while libbpf will resolve address to
unknown kfunc as ld_imm64 reg, 0 which will also be recognized by
is_branch_taken() and the verifier will proceed dead code elimination. BPF
programs can use this logic to detect at load time whether kfunc is present in
the kernel with bpf_ksym_exists() macro that is introduced in the next patches.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Martin KaFai Lau <martin.lau@kernel.org>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20230317201920.62030-2-alexei.starovoitov@gmail.com
Replace mutex_[un]lock() with cgroup_[un]lock() wrappers to stay
consistent across cgroup core and other subsystem code, while
operating on the cgroup_mutex.
Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Moving find_kallsyms_symbol_value from kernel/module/internal.h to
include/linux/module.h. The reason is that internal.h is not prepared to
be included when CONFIG_MODULES=n. find_kallsyms_symbol_value is used by
kernel/bpf/verifier.c and including internal.h from it (without modules)
leads into a compilation error:
In file included from ../include/linux/container_of.h:5,
from ../include/linux/list.h:5,
from ../include/linux/timer.h:5,
from ../include/linux/workqueue.h:9,
from ../include/linux/bpf.h:10,
from ../include/linux/bpf-cgroup.h:5,
from ../kernel/bpf/verifier.c:7:
../kernel/bpf/../module/internal.h: In function 'mod_find':
../include/linux/container_of.h:20:54: error: invalid use of undefined type 'struct module'
20 | static_assert(__same_type(*(ptr), ((type *)0)->member) || \
| ^~
[...]
This patch fixes the above error.
Fixes: 31bf1dbccf ("bpf: Fix attaching fentry/fexit/fmod_ret/lsm to modules")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Viktor Malik <vmalik@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/oe-kbuild-all/202303161404.OrmfCy09-lkp@intel.com/
Link: https://lore.kernel.org/bpf/20230317095601.386738-1-vmalik@redhat.com
For every BPF_ADD/SUB involving a pointer, adjust_ptr_min_max_vals()
ensures that the resulting pointer has a constant offset if
bypass_spec_v1 is false. This is ensured by calling sanitize_check_bounds()
which in turn calls check_stack_access_for_ptr_arithmetic(). There,
-EACCESS is returned if the register's offset is not constant, thereby
rejecting the program.
In summary, an unprivileged user must never be able to create stack
pointers with a variable offset. That is also the case, because a
respective check in check_stack_write() is missing. If they were able
to create a variable-offset pointer, users could still use it in a
stack-write operation to trigger unsafe speculative behavior [1].
Because unprivileged users must already be prevented from creating
variable-offset stack pointers, viable options are to either remove
this check (replacing it with a clarifying comment), or to turn it
into a "verifier BUG"-message, also adding a similar check in
check_stack_write() (for consistency, as a second-level defense).
This patch implements the first option to reduce verifier bloat.
This check was introduced by commit 01f810ace9 ("bpf: Allow
variable-offset stack access") which correctly notes that
"variable-offset reads and writes are disallowed (they were already
disallowed for the indirect access case) because the speculative
execution checking code doesn't support them". However, it does not
further discuss why the check in check_stack_read() is necessary.
The code which made this check obsolete was also introduced in this
commit.
I have compiled ~650 programs from the Linux selftests, Linux samples,
Cilium, and libbpf/examples projects and confirmed that none of these
trigger the check in check_stack_read() [2]. Instead, all of these
programs are, as expected, already rejected when constructing the
variable-offset pointers. Note that the check in
check_stack_access_for_ptr_arithmetic() also prints "off=%d" while the
code removed by this patch does not (the error removed does not appear
in the "verification_error" values). For reproducibility, the
repository linked includes the raw data and scripts used to create
the plot.
[1] https://arxiv.org/pdf/1807.03757.pdf
[2] 53dc19fcf4/data/plots/23-02-26_23-56_bpftool/bpftool/0004-errors.pdf
Fixes: 01f810ace9 ("bpf: Allow variable-offset stack access")
Signed-off-by: Luis Gerhorst <gerhorst@cs.fau.de>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20230315165358.23701-1-gerhorst@cs.fau.de
Now that struct bpf_cpumask is RCU safe, there's no need for this kfunc.
Rather than doing the following:
private(MASK) static struct bpf_cpumask __kptr *global;
int BPF_PROG(prog, s32 cpu, ...)
{
struct bpf_cpumask *cpumask;
bpf_rcu_read_lock();
cpumask = bpf_cpumask_kptr_get(&global);
if (!cpumask) {
bpf_rcu_read_unlock();
return -1;
}
bpf_cpumask_setall(cpumask);
...
bpf_cpumask_release(cpumask);
bpf_rcu_read_unlock();
}
Programs can instead simply do (assume same global cpumask):
int BPF_PROG(prog, ...)
{
struct bpf_cpumask *cpumask;
bpf_rcu_read_lock();
cpumask = global;
if (!cpumask) {
bpf_rcu_read_unlock();
return -1;
}
bpf_cpumask_setall(cpumask);
...
bpf_rcu_read_unlock();
}
In other words, no extra atomic acquire / release, and less boilerplate
code.
This patch removes both the kfunc, as well as its selftests and
documentation.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230316054028.88924-5-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
struct bpf_cpumask is a BPF-wrapper around the struct cpumask type which
can be instantiated by a BPF program, and then queried as a cpumask in
similar fashion to normal kernel code. The previous patch in this series
makes the type fully RCU safe, so the type can be included in the
rcu_protected_type BTF ID list.
A subsequent patch will remove bpf_cpumask_kptr_get(), as it's no longer
useful now that we can just treat the type as RCU safe by default and do
our own if check.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230316054028.88924-3-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The struct bpf_cpumask type uses the bpf_mem_cache_{alloc,free}() APIs
to allocate and free its cpumasks. The bpf_mem allocator may currently
immediately reuse some memory when its freed, without waiting for an RCU
read cycle to elapse. We want to be able to treat struct bpf_cpumask
objects as completely RCU safe.
This is necessary for two reasons:
1. bpf_cpumask_kptr_get() currently does an RCU-protected
refcnt_inc_not_zero(). This of course assumes that the underlying
memory is not reused, and is therefore unsafe in its current form.
2. We want to be able to get rid of bpf_cpumask_kptr_get() entirely, and
intead use the superior kptr RCU semantics now afforded by the
verifier.
This patch fixes (1), and enables (2), by making struct bpf_cpumask RCU
safe. A subsequent patch will update the verifier to allow struct
bpf_cpumask * pointers to be passed to KF_RCU kfuncs, and then a latter
patch will remove bpf_cpumask_kptr_get().
Fixes: 516f4d3397 ("bpf: Enable cpumasks to be queried and used as kptrs")
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230316054028.88924-2-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This resolves two problems with attachment of fentry/fexit/fmod_ret/lsm
to functions located in modules:
1. The verifier tries to find the address to attach to in kallsyms. This
is always done by searching the entire kallsyms, not respecting the
module in which the function is located. Such approach causes an
incorrect attachment address to be computed if the function to attach
to is shadowed by a function of the same name located earlier in
kallsyms.
2. If the address to attach to is located in a module, the module
reference is only acquired in register_fentry. If the module is
unloaded between the place where the address is found
(bpf_check_attach_target in the verifier) and register_fentry, it is
possible that another module is loaded to the same address which may
lead to potential errors.
Since the attachment must contain the BTF of the program to attach to,
we extract the module from it and search for the function address in the
correct module (resolving problem no. 1). Then, the module reference is
taken directly in bpf_check_attach_target and stored in the bpf program
(in bpf_prog_aux). The reference is only released when the program is
unloaded (resolving problem no. 2).
Signed-off-by: Viktor Malik <vmalik@redhat.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/3f6a9d8ae850532b5ef864ef16327b0f7a669063.1678432753.git.vmalik@redhat.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The verifier rejects the code:
bpf_strncmp(task->comm, 16, "my_task");
with the message:
16: (85) call bpf_strncmp#182
R1 type=trusted_ptr_ expected=fp, pkt, pkt_meta, map_key, map_value, mem, ringbuf_mem, buf
Teach the verifier that such access pattern is safe.
Do not allow untrusted and legacy ptr_to_btf_id to be passed into helpers.
Reported-by: David Vernet <void@manifault.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230313235845.61029-3-alexei.starovoitov@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
bpf_strncmp() doesn't write into its first argument.
Make sure that the verifier knows about it.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230313235845.61029-2-alexei.starovoitov@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
When a local kptr is stashed in a map and freed when the map goes away,
currently an error like the below appears:
[ 39.195695] BUG: using smp_processor_id() in preemptible [00000000] code: kworker/u32:15/2875
[ 39.196549] caller is bpf_mem_free+0x56/0xc0
[ 39.196958] CPU: 15 PID: 2875 Comm: kworker/u32:15 Tainted: G O 6.2.0-13016-g22df776a9a86 #4477
[ 39.197897] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
[ 39.198949] Workqueue: events_unbound bpf_map_free_deferred
[ 39.199470] Call Trace:
[ 39.199703] <TASK>
[ 39.199911] dump_stack_lvl+0x60/0x70
[ 39.200267] check_preemption_disabled+0xbf/0xe0
[ 39.200704] bpf_mem_free+0x56/0xc0
[ 39.201032] ? bpf_obj_new_impl+0xa0/0xa0
[ 39.201430] bpf_obj_free_fields+0x1cd/0x200
[ 39.201838] array_map_free+0xad/0x220
[ 39.202193] ? finish_task_switch+0xe5/0x3c0
[ 39.202614] bpf_map_free_deferred+0xea/0x210
[ 39.203006] ? lockdep_hardirqs_on_prepare+0xe/0x220
[ 39.203460] process_one_work+0x64f/0xbe0
[ 39.203822] ? pwq_dec_nr_in_flight+0x110/0x110
[ 39.204264] ? do_raw_spin_lock+0x107/0x1c0
[ 39.204662] ? lockdep_hardirqs_on_prepare+0xe/0x220
[ 39.205107] worker_thread+0x74/0x7a0
[ 39.205451] ? process_one_work+0xbe0/0xbe0
[ 39.205818] kthread+0x171/0x1a0
[ 39.206111] ? kthread_complete_and_exit+0x20/0x20
[ 39.206552] ret_from_fork+0x1f/0x30
[ 39.206886] </TASK>
This happens because the call to __bpf_obj_drop_impl I added in the patch
adding support for stashing local kptrs doesn't disable migration. Prior
to that patch, __bpf_obj_drop_impl logic only ran when called by a BPF
progarm, whereas now it can be called from map free path, so it's
necessary to explicitly disable migration.
Also, refactor a bit to just call __bpf_obj_drop_impl directly instead
of bothering w/ dtor union and setting pointer-to-obj_drop.
Fixes: c8e1875409 ("bpf: Support __kptr to local kptrs")
Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230313214641.3731908-1-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Merge commit bf9bec4cb3 ("Merge branch 'bpf: Allow reads from uninit stack'")
from bpf-next to bpf tree to address verification issues in some programs
due to stack usage.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Fix wrong order of frame index vs register/slot index in precision
propagation verbose (level 2) output. It's wrong and very confusing as is.
Fixes: 529409ea92 ("bpf: propagate precision across all frames, not just the last one")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230313184017.4083374-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The previous patch added necessary plumbing for verifier and runtime to
know what to do with non-kernel PTR_TO_BTF_IDs in map values, but didn't
provide any way to get such local kptrs into a map value. This patch
modifies verifier handling of bpf_kptr_xchg to allow MEM_ALLOC kptr
types.
check_reg_type is modified accept MEM_ALLOC-flagged input to
bpf_kptr_xchg despite such types not being in btf_ptr_types. This could
have been done with a MAYBE_MEM_ALLOC equivalent to MAYBE_NULL, but
bpf_kptr_xchg is the only helper that I can forsee using
MAYBE_MEM_ALLOC, so keep it special-cased for now.
The verifier tags bpf_kptr_xchg retval MEM_ALLOC if and only if the BTF
associated with the retval is not kernel BTF.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230310230743.2320707-3-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
If a PTR_TO_BTF_ID type comes from program BTF - not vmlinux or module
BTF - it must have been allocated by bpf_obj_new and therefore must be
free'd with bpf_obj_drop. Such a PTR_TO_BTF_ID is considered a "local
kptr" and is tagged with MEM_ALLOC type tag by bpf_obj_new.
This patch adds support for treating __kptr-tagged pointers to "local
kptrs" as having an implicit bpf_obj_drop destructor for referenced kptr
acquire / release semantics. Consider the following example:
struct node_data {
long key;
long data;
struct bpf_rb_node node;
};
struct map_value {
struct node_data __kptr *node;
};
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__type(key, int);
__type(value, struct map_value);
__uint(max_entries, 1);
} some_nodes SEC(".maps");
If struct node_data had a matching definition in kernel BTF, the verifier would
expect a destructor for the type to be registered. Since struct node_data does
not match any type in kernel BTF, the verifier knows that there is no kfunc
that provides a PTR_TO_BTF_ID to this type, and that such a PTR_TO_BTF_ID can
only come from bpf_obj_new. So instead of searching for a registered dtor,
a bpf_obj_drop dtor can be assumed.
This allows the runtime to properly destruct such kptrs in
bpf_obj_free_fields, which enables maps to clean up map_vals w/ such
kptrs when going away.
Implementation notes:
* "kernel_btf" variable is renamed to "kptr_btf" in btf_parse_kptr.
Before this patch, the variable would only ever point to vmlinux or
module BTFs, but now it can point to some program BTF for local kptr
type. It's later used to populate the (btf, btf_id) pair in kptr btf
field.
* It's necessary to btf_get the program BTF when populating btf_field
for local kptr. btf_record_free later does a btf_put.
* Behavior for non-local referenced kptrs is not modified, as
bpf_find_btf_id helper only searches vmlinux and module BTFs for
matching BTF type. If such a type is found, btf_field_kptr's btf will
pass btf_is_kernel check, and the associated release function is
some one-argument dtor. If btf_is_kernel check fails, associated
release function is two-arg bpf_obj_drop_impl. Before this patch
only btf_field_kptr's w/ kernel or module BTFs were created.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230310230743.2320707-2-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
btf_record_find's 3rd parameter can be multiple enum btf_field_type's
masked together. The function is called with BPF_KPTR in two places in
verifier.c, so it works with masked values already.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230309180111.1618459-4-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This enum was added and used in commit aa3496accc ("bpf: Refactor kptr_off_tab
into btf_record"). Later refactoring in commit db55911782 ("bpf: Consolidate
spin_lock, timer management into btf_record") resulted in the enum
values no longer being used anywhere.
Let's remove them.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230309180111.1618459-3-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
kernel_type_name was introduced in commit 9e15db6613 ("bpf: Implement accurate raw_tp context access via BTF")
with type signature:
const char *kernel_type_name(u32 id)
At that time the function used global btf_vmlinux BTF for all id lookups. Later,
in commit 22dc4a0f5e ("bpf: Remove hard-coded btf_vmlinux assumption from BPF verifier"),
the type signature was changed to:
static const char *kernel_type_name(const struct btf* btf, u32 id)
With the btf parameter used for lookups instead of global btf_vmlinux.
The helper will function as expected for type name lookup using non-kernel BTFs,
and will be used for such in further patches in the series. Let's rename it to
avoid incorrect assumptions that might arise when seeing the current name.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230309180111.1618459-2-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch refactors local_storage freeing logic into
bpf_local_storage_free(). It is a preparation work for a later
patch that uses bpf_mem_cache_alloc/free. The other kfree(local_storage)
cases are also changed to bpf_local_storage_free(..., reuse_now = true).
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20230308065936.1550103-12-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The existing bpf_local_storage_free_rcu is renamed to
bpf_local_storage_free_trace_rcu. A new bpf_local_storage_rcu
callback is added to do the kfree instead of using kfree_rcu.
It is a preparation work for a later patch using
bpf_mem_cache_alloc/free.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20230308065936.1550103-11-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch refactors the selem freeing logic into bpf_selem_free().
It is a preparation work for a later patch using
bpf_mem_cache_alloc/free. The other kfree(selem) cases
are also changed to bpf_selem_free(..., reuse_now = true).
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20230308065936.1550103-10-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add bpf_selem_free_rcu() callback to do the kfree() instead
of using kfree_rcu. It is a preparation work for using
bpf_mem_cache_alloc/free in a later patch.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20230308065936.1550103-9-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch removes the bpf_selem_free_fields*_rcu. The
bpf_obj_free_fields() can be done before the call_rcu_trasks_trace()
and kfree_rcu(). It is needed when a later patch uses
bpf_mem_cache_alloc/free. In bpf hashtab, bpf_obj_free_fields()
is also called before calling bpf_mem_cache_free. The discussion
can be found in
https://lore.kernel.org/bpf/f67021ee-21d9-bfae-6134-4ca542fab843@linux.dev/
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20230308065936.1550103-8-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch re-purpose the use_trace_rcu to mean
if the freed memory can be reused immediately or not.
The use_trace_rcu is renamed to reuse_now. Other than
the boolean test is reversed, it should be a no-op.
The following explains the reason for the rename and how it will
be used in a later patch.
In a later patch, bpf_mem_cache_alloc/free will be used
in the bpf_local_storage. The bpf mem allocator will reuse
the freed memory immediately. Some of the free paths in
bpf_local_storage does not support memory to be reused immediately.
These paths are the "delete" elem cases from the bpf_*_storage_delete()
helper and the map_delete_elem() syscall. Note that "delete" elem
before the owner's (sk/task/cgrp/inode) lifetime ended is not
the common usage for the local storage.
The common free path, bpf_local_storage_destroy(), can reuse the
memory immediately. This common path means the storage stays with
its owner until the owner is destroyed.
The above mentioned "delete" elem paths that cannot
reuse immediately always has the 'use_trace_rcu == true'.
The cases that is safe for immediate reuse always have
'use_trace_rcu == false'. Instead of adding another arg
in a later patch, this patch re-purpose this arg
to reuse_now and have the test logic reversed.
In a later patch, 'reuse_now == true' will free to the
bpf_mem_cache_free() where the memory can be reused
immediately. 'reuse_now == false' will go through the
call_rcu_tasks_trace().
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20230308065936.1550103-7-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch remembers which smap triggers the allocation
of a 'struct bpf_local_storage' object. The local_storage is
allocated during the very first selem added to the owner.
The smap pointer is needed when using the bpf_mem_cache_free
in a later patch because it needs to free to the correct
smap's bpf_mem_alloc object.
When a selem is being removed, it needs to check if it is
the selem that triggers the creation of the local_storage.
If it is, the local_storage->smap pointer will be reset to NULL.
This NULL reset is done under the local_storage->lock in
bpf_selem_unlink_storage_nolock() when a selem is being removed.
Also note that the local_storage may not go away even
local_storage->smap is NULL because there may be other
selem still stored in the local_storage.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20230308065936.1550103-6-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
__bpf_selem_unlink_storage is taking the spin lock and there is
no name collision also. Having the preceding '__' is confusing
when reviewing the later patch.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20230308065936.1550103-5-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
bpf_local_storage_map_alloc() is the only caller of
__bpf_local_storage_map_alloc(). The remaining logic in
bpf_local_storage_map_alloc() is only a one liner setting
the smap->cache_idx.
Remove __bpf_local_storage_map_alloc() to simplify code.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20230308065936.1550103-4-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch first renames bpf_local_storage_unlink_nolock to
bpf_local_storage_destroy(). It better reflects that it is only
used when the storage's owner (sk/task/cgrp/inode) is being kfree().
All bpf_local_storage_destroy's caller is taking the spin lock and
then free the storage. This patch also moves these two steps into
the bpf_local_storage_destroy.
This is a preparation work for a later patch that uses
bpf_mem_cache_alloc/free in the bpf_local_storage.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20230308065936.1550103-3-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch moves the bpf_local_storage_free_rcu() and
bpf_selem_unlink_map() to static because they are
not used outside of bpf_local_storage.c.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20230308065936.1550103-2-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When doing state comparison, if old state has register that is not
marked as REG_LIVE_READ, then we just skip comparison, regardless what's
the state of corresponing register in current state. This is because not
REG_LIVE_READ register is irrelevant for further program execution and
correctness. All good here.
But when we get to precision propagation, after two states were declared
equivalent, we don't take into account old register's liveness, and thus
attempt to propagate precision for register in current state even if
that register in old state was not REG_LIVE_READ anymore. This is bad,
because register in current state could be anything at all and this
could cause -EFAULT due to internal logic bugs.
Fix by taking into account REG_LIVE_READ liveness mark to keep the logic
in state comparison in sync with precision propagation.
Fixes: a3ce685dd0 ("bpf: fix precision tracking")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230309224131.57449-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
State equivalence check and checkpointing performed in is_state_visited()
employs certain heuristics to try to save memory by avoiding state checkpoints
if not enough jumps and instructions happened since last checkpoint. This leads
to unpredictability of whether a particular instruction will be checkpointed
and how regularly. While normally this is not causing much problems (except
inconveniences for predictable verifier tests, which we overcome with
BPF_F_TEST_STATE_FREQ flag), turns out it's not the case for open-coded
iterators.
Checking and saving state checkpoints at iter_next() call is crucial for fast
convergence of open-coded iterator loop logic, so we need to force it. If we
don't do that, is_state_visited() might skip saving a checkpoint, causing
unnecessarily long sequence of not checkpointed instructions and jumps, leading
to exhaustion of jump history buffer, and potentially other undesired outcomes.
It is expected that with correct open-coded iterators convergence will happen
quickly, so we don't run a risk of exhausting memory.
This patch adds, in addition to prune and jump instruction marks, also a
"forced checkpoint" mark, and makes sure that any iter_next() call instruction
is marked as such.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230310060149.625887-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Implement the first open-coded iterator type over a range of integers.
It's public API consists of:
- bpf_iter_num_new() constructor, which accepts [start, end) range
(that is, start is inclusive, end is exclusive).
- bpf_iter_num_next() which will keep returning read-only pointer to int
until the range is exhausted, at which point NULL will be returned.
If bpf_iter_num_next() is kept calling after this, NULL will be
persistently returned.
- bpf_iter_num_destroy() destructor, which needs to be called at some
point to clean up iterator state. BPF verifier enforces that iterator
destructor is called at some point before BPF program exits.
Note that `start = end = X` is a valid combination to setup an empty
iterator. bpf_iter_num_new() will return 0 (success) for any such
combination.
If bpf_iter_num_new() detects invalid combination of input arguments, it
returns error, resets iterator state to, effectively, empty iterator, so
any subsequent call to bpf_iter_num_next() will keep returning NULL.
BPF verifier has no knowledge that returned integers are in the
[start, end) value range, as both `start` and `end` are not statically
known and enforced: they are runtime values.
While the implementation is pretty trivial, some care needs to be taken
to avoid overflows and underflows. Subsequent selftests will validate
correctness of [start, end) semantics, especially around extremes
(INT_MIN and INT_MAX).
Similarly to bpf_loop(), we enforce that no more than BPF_MAX_LOOPS can
be specified.
bpf_iter_num_{new,next,destroy}() is a logical evolution from bounded
BPF loops and bpf_loop() helper and is the basis for implementing
ergonomic BPF loops with no statically known or verified bounds.
Subsequent patches implement bpf_for() macro, demonstrating how this can
be wrapped into something that works and feels like a normal for() loop
in C language.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230308184121.1165081-5-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Teach verifier about the concept of the open-coded (or inline) iterators.
This patch adds generic iterator loop verification logic, new STACK_ITER
stack slot type to contain iterator state, and necessary kfunc plumbing
for iterator's constructor, destructor and next methods. Next patch
implements first specific iterator (numbers iterator for implementing
for() loop logic). Such split allows to have more focused commits for
verifier logic and separate commit that we could point later to
demonstrating what does it take to add a new kind of iterator.
Each kind of iterator has its own associated struct bpf_iter_<type>,
where <type> denotes a specific type of iterator. struct bpf_iter_<type>
state is supposed to live on BPF program stack, so there will be no way
to change its size later on without breaking backwards compatibility, so
choose wisely! But given this struct is specific to a given <type> of
iterator, this allows a lot of flexibility: simple iterators could be
fine with just one stack slot (8 bytes), like numbers iterator in the
next patch, while some other more complicated iterators might need way
more to keep their iterator state. Either way, such design allows to
avoid runtime memory allocations, which otherwise would be necessary if
we fixed on-the-stack size and it turned out to be too small for a given
iterator implementation.
The way BPF verifier logic is implemented, there are no artificial
restrictions on a number of active iterators, it should work correctly
using multiple active iterators at the same time. This also means you
can have multiple nested iteration loops. struct bpf_iter_<type>
reference can be safely passed to subprograms as well.
General flow is easiest to demonstrate with a simple example using
number iterator implemented in next patch. Here's the simplest possible
loop:
struct bpf_iter_num it;
int *v;
bpf_iter_num_new(&it, 2, 5);
while ((v = bpf_iter_num_next(&it))) {
bpf_printk("X = %d", *v);
}
bpf_iter_num_destroy(&it);
Above snippet should output "X = 2", "X = 3", "X = 4". Note that 5 is
exclusive and is not returned. This matches similar APIs (e.g., slices
in Go or Rust) that implement a range of elements, where end index is
non-inclusive.
In the above example, we see a trio of function:
- constructor, bpf_iter_num_new(), which initializes iterator state
(struct bpf_iter_num it) on the stack. If any of the input arguments
are invalid, constructor should make sure to still initialize it such
that subsequent bpf_iter_num_next() calls will return NULL. I.e., on
error, return error and construct empty iterator.
- next method, bpf_iter_num_next(), which accepts pointer to iterator
state and produces an element. Next method should always return
a pointer. The contract between BPF verifier is that next method will
always eventually return NULL when elements are exhausted. Once NULL is
returned, subsequent next calls should keep returning NULL. In the
case of numbers iterator, bpf_iter_num_next() returns a pointer to an int
(storage for this integer is inside the iterator state itself),
which can be dereferenced after corresponding NULL check.
- once done with the iterator, it's mandated that user cleans up its
state with the call to destructor, bpf_iter_num_destroy() in this
case. Destructor frees up any resources and marks stack space used by
struct bpf_iter_num as usable for something else.
Any other iterator implementation will have to implement at least these
three methods. It is enforced that for any given type of iterator only
applicable constructor/destructor/next are callable. I.e., verifier
ensures you can't pass number iterator state into, say, cgroup
iterator's next method.
It is important to keep the naming pattern consistent to be able to
create generic macros to help with BPF iter usability. E.g., one
of the follow up patches adds generic bpf_for_each() macro to bpf_misc.h
in selftests, which allows to utilize iterator "trio" nicely without
having to code the above somewhat tedious loop explicitly every time.
This is enforced at kfunc registration point by one of the previous
patches in this series.
At the implementation level, iterator state tracking for verification
purposes is very similar to dynptr. We add STACK_ITER stack slot type,
reserve necessary number of slots, depending on
sizeof(struct bpf_iter_<type>), and keep track of necessary extra state
in the "main" slot, which is marked with non-zero ref_obj_id. Other
slots are also marked as STACK_ITER, but have zero ref_obj_id. This is
simpler than having a separate "is_first_slot" flag.
Another big distinction is that STACK_ITER is *always refcounted*, which
simplifies implementation without sacrificing usability. So no need for
extra "iter_id", no need to anticipate reuse of STACK_ITER slots for new
constructors, etc. Keeping it simple here.
As far as the verification logic goes, there are two extensive comments:
in process_iter_next_call() and iter_active_depths_differ() explaining
some important and sometimes subtle aspects. Please refer to them for
details.
But from 10,000-foot point of view, next methods are the points of
forking a verification state, which are conceptually similar to what
verifier is doing when validating conditional jump. We branch out at
a `call bpf_iter_<type>_next` instruction and simulate two outcomes:
NULL (iteration is done) and non-NULL (new element is returned). NULL is
simulated first and is supposed to reach exit without looping. After
that non-NULL case is validated and it either reaches exit (for trivial
examples with no real loop), or reaches another `call bpf_iter_<type>_next`
instruction with the state equivalent to already (partially) validated
one. State equivalency at that point means we technically are going to
be looping forever without "breaking out" out of established "state
envelope" (i.e., subsequent iterations don't add any new knowledge or
constraints to the verifier state, so running 1, 2, 10, or a million of
them doesn't matter). But taking into account the contract stating that
iterator next method *has to* return NULL eventually, we can conclude
that loop body is safe and will eventually terminate. Given we validated
logic outside of the loop (NULL case), and concluded that loop body is
safe (though potentially looping many times), verifier can claim safety
of the overall program logic.
The rest of the patch is necessary plumbing for state tracking, marking,
validation, and necessary further kfunc plumbing to allow implementing
iterator constructor, destructor, and next methods.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230308184121.1165081-4-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add ability to register kfuncs that implement BPF open-coded iterator
contract and enforce naming and function proto convention. Enforcement
happens at the time of kfunc registration and significantly simplifies
the rest of iterators logic in the verifier.
More details follow in subsequent patches, but we enforce the following
conditions.
All kfuncs (constructor, next, destructor) have to be named consistenly
as bpf_iter_<type>_{new,next,destroy}(), respectively. <type> represents
iterator type, and iterator state should be represented as a matching
`struct bpf_iter_<type>` state type. Also, all iter kfuncs should have
a pointer to this `struct bpf_iter_<type>` as the very first argument.
Additionally:
- Constructor, i.e., bpf_iter_<type>_new(), can have arbitrary extra
number of arguments. Return type is not enforced either.
- Next method, i.e., bpf_iter_<type>_next(), has to return a pointer
type and should have exactly one argument: `struct bpf_iter_<type> *`
(const/volatile/restrict and typedefs are ignored).
- Destructor, i.e., bpf_iter_<type>_destroy(), should return void and
should have exactly one argument, similar to the next method.
- struct bpf_iter_<type> size is enforced to be positive and
a multiple of 8 bytes (to fit stack slots correctly).
Such strictness and consistency allows to build generic helpers
abstracting important, but boilerplate, details to be able to use
open-coded iterators effectively and ergonomically (see bpf_for_each()
in subsequent patches). It also simplifies the verifier logic in some
places. At the same time, this doesn't hurt generality of possible
iterator implementations. Win-win.
Constructor kfunc is marked with a new KF_ITER_NEW flags, next method is
marked with KF_ITER_NEXT (and should also have KF_RET_NULL, of course),
while destructor kfunc is marked as KF_ITER_DESTROY.
Additionally, we add a trivial kfunc name validation: it should be
a valid non-NULL and non-empty string.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230308184121.1165081-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Factor out logic to fetch basic kfunc metadata based on struct bpf_insn.
This is not exactly short or trivial code to just copy/paste and this
information is sometimes necessary in other parts of the verifier logic.
Subsequent patches will rely on this to determine if an instruction is
a kfunc call to iterator next method.
No functional changes intended, including that verbose() warning
behavior when kfunc is not allowed for a particular program type.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230308184121.1165081-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
We have implemented memory usage callback for all maps, and we enforce
any newly added map having a callback as well. We check this callback at
map creation time. If it doesn't have the callback, we will return
EINVAL.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20230305124615.12358-19-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
A new helper is introduced to calculate offload map memory usage. But
currently the memory dynamically allocated in netdev dev_ops, like
nsim_map_update_elem, is not counted. Let's just put it aside now.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20230305124615.12358-18-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
A new helper is introduced into bpf_local_storage map to calculate the
memory usage. This helper is also used by other maps like
bpf_cgrp_storage, bpf_inode_storage, bpf_task_storage and etc.
Note that currently the dynamically allocated storage elements are not
counted in the usage, since it will take extra runtime overhead in the
elements update or delete path. So let's put it aside now, and implement
it in the future when someone really need it.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20230305124615.12358-15-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
A new helper is introduced to calculate local_storage map memory usage.
Currently the dynamically allocated elements are not counted, since it
will take runtime overhead in the element update or delete path. So
let's put it aside currently, and implement it in the future if the user
really needs it.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20230305124615.12358-14-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
A new helper is introduced to calculate bpf_struct_ops memory usage.
The result as follows,
- before
1: struct_ops name count_map flags 0x0
key 4B value 256B max_entries 1 memlock 4096B
btf_id 73
- after
1: struct_ops name count_map flags 0x0
key 4B value 256B max_entries 1 memlock 5016B
btf_id 73
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20230305124615.12358-13-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
A new helper is introduced to calculate queue_stack_maps memory usage.
The result as follows,
- before
20: queue name count_map flags 0x0
key 0B value 4B max_entries 65536 memlock 266240B
21: stack name count_map flags 0x0
key 0B value 4B max_entries 65536 memlock 266240B
- after
20: queue name count_map flags 0x0
key 0B value 4B max_entries 65536 memlock 524288B
21: stack name count_map flags 0x0
key 0B value 4B max_entries 65536 memlock 524288B
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20230305124615.12358-12-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
A new helper is introduced to calculate the memory usage of devmap and
devmap_hash. The number of dynamically allocated elements are recored
for devmap_hash already, but not for devmap. To track the memory size of
dynamically allocated elements, this patch also count the numbers for
devmap.
The result as follows,
- before
40: devmap name count_map flags 0x80
key 4B value 4B max_entries 65536 memlock 524288B
41: devmap_hash name count_map flags 0x80
key 4B value 4B max_entries 65536 memlock 524288B
- after
40: devmap name count_map flags 0x80 <<<< no elements
key 4B value 4B max_entries 65536 memlock 524608B
41: devmap_hash name count_map flags 0x80 <<<< no elements
key 4B value 4B max_entries 65536 memlock 524608B
Note that the number of buckets is same with max_entries for devmap_hash
in this case.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20230305124615.12358-11-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
A new helper is introduced to calculate cpumap memory usage. The size of
cpu_entries can be dynamically changed when we update or delete a cpumap
element, but this patch doesn't include the memory size of cpu_entry
yet. We can dynamically calculate the memory usage when we alloc or free
a cpu_entry, but it will take extra runtime overhead, so let just put it
aside currently. Note that the size of different cpu_entry may be
different as well.
The result as follows,
- before
48: cpumap name count_map flags 0x4
key 4B value 4B max_entries 64 memlock 4096B
- after
48: cpumap name count_map flags 0x4
key 4B value 4B max_entries 64 memlock 832B
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20230305124615.12358-10-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Introduce a new helper to calculate the bloom_filter memory usage.
The result as follows,
- before
16: bloom_filter flags 0x0
key 0B value 8B max_entries 65536 memlock 524288B
- after
16: bloom_filter flags 0x0
key 0B value 8B max_entries 65536 memlock 65856B
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20230305124615.12358-9-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
A new helper ringbuf_map_mem_usage() is introduced to calculate ringbuf
memory usage.
The result as follows,
- before
15: ringbuf name count_map flags 0x0
key 0B value 0B max_entries 65536 memlock 0B
- after
15: ringbuf name count_map flags 0x0
key 0B value 0B max_entries 65536 memlock 78424B
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230305124615.12358-8-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
A new helper is introduced to calculate reuseport_array memory usage.
The result as follows,
- before
14: reuseport_sockarray name count_map flags 0x0
key 4B value 8B max_entries 65536 memlock 1048576B
- after
14: reuseport_sockarray name count_map flags 0x0
key 4B value 8B max_entries 65536 memlock 524544B
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20230305124615.12358-7-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
A new helper is introduced to get stackmap memory usage. Some small
memory allocations are ignored as their memory size is quite small
compared to the totol usage.
The result as follows,
- before
16: stack_trace name count_map flags 0x0
key 4B value 8B max_entries 65536 memlock 1048576B
- after
16: stack_trace name count_map flags 0x0
key 4B value 8B max_entries 65536 memlock 2097472B
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20230305124615.12358-6-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Introduce array_map_mem_usage() to calculate arraymap memory usage. In
this helper, some small memory allocations are ignored, like the
allocation of struct bpf_array_aux in prog_array. The inner_map_meta in
array_of_map is also ignored.
The result as follows,
- before
11: array name count_map flags 0x0
key 4B value 4B max_entries 65536 memlock 524288B
12: percpu_array name count_map flags 0x0
key 4B value 4B max_entries 65536 memlock 8912896B
13: perf_event_array name count_map flags 0x0
key 4B value 4B max_entries 65536 memlock 524288B
14: prog_array name count_map flags 0x0
key 4B value 4B max_entries 65536 memlock 524288B
15: cgroup_array name count_map flags 0x0
key 4B value 4B max_entries 65536 memlock 524288B
- after
11: array name count_map flags 0x0
key 4B value 4B max_entries 65536 memlock 524608B
12: percpu_array name count_map flags 0x0
key 4B value 4B max_entries 65536 memlock 17301824B
13: perf_event_array name count_map flags 0x0
key 4B value 4B max_entries 65536 memlock 524608B
14: prog_array name count_map flags 0x0
key 4B value 4B max_entries 65536 memlock 524608B
15: cgroup_array name count_map flags 0x0
key 4B value 4B max_entries 65536 memlock 524608B
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20230305124615.12358-5-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
htab_map_mem_usage() is introduced to calculate hashmap memory usage. In
this helper, some small memory allocations are ignore, as their size is
quite small compared with the total size. The inner_map_meta in
hash_of_map is also ignored.
The result for hashtab as follows,
- before this change
1: hash name count_map flags 0x1 <<<< no prealloc, fully set
key 16B value 24B max_entries 1048576 memlock 41943040B
2: hash name count_map flags 0x1 <<<< no prealloc, none set
key 16B value 24B max_entries 1048576 memlock 41943040B
3: hash name count_map flags 0x0 <<<< prealloc
key 16B value 24B max_entries 1048576 memlock 41943040B
The memlock is always a fixed size whatever it is preallocated or
not, and whatever the count of allocated elements is.
- after this change
1: hash name count_map flags 0x1 <<<< non prealloc, fully set
key 16B value 24B max_entries 1048576 memlock 117441536B
2: hash name count_map flags 0x1 <<<< non prealloc, non set
key 16B value 24B max_entries 1048576 memlock 16778240B
3: hash name count_map flags 0x0 <<<< prealloc
key 16B value 24B max_entries 1048576 memlock 109056000B
The memlock now is hashtab actually allocated.
The result for percpu hash map as follows,
- before this change
4: percpu_hash name count_map flags 0x0 <<<< prealloc
key 16B value 24B max_entries 1048576 memlock 822083584B
5: percpu_hash name count_map flags 0x1 <<<< no prealloc
key 16B value 24B max_entries 1048576 memlock 822083584B
- after this change
4: percpu_hash name count_map flags 0x0
key 16B value 24B max_entries 1048576 memlock 897582080B
5: percpu_hash name count_map flags 0x1
key 16B value 24B max_entries 1048576 memlock 922748736B
At worst, the difference can be 10x, for example,
- before this change
6: hash name count_map flags 0x0
key 4B value 4B max_entries 1048576 memlock 8388608B
- after this change
6: hash name count_map flags 0x0
key 4B value 4B max_entries 1048576 memlock 83889408B
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20230305124615.12358-4-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
trie_mem_usage() is introduced to calculate the lpm_trie memory usage.
Some small memory allocations are ignored. The inner node is also
ignored.
The result as follows,
- before
10: lpm_trie flags 0x1
key 8B value 8B max_entries 65536 memlock 1048576B
- after
10: lpm_trie flags 0x1
key 8B value 8B max_entries 65536 memlock 2291536B
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20230305124615.12358-3-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add a new map ops ->map_mem_usage to print the memory usage of a
bpf map.
This is a preparation for the followup change.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20230305124615.12358-2-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:
====================
pull-request: bpf-next 2023-03-06
We've added 85 non-merge commits during the last 13 day(s) which contain
a total of 131 files changed, 7102 insertions(+), 1792 deletions(-).
The main changes are:
1) Add skb and XDP typed dynptrs which allow BPF programs for more
ergonomic and less brittle iteration through data and variable-sized
accesses, from Joanne Koong.
2) Bigger batch of BPF verifier improvements to prepare for upcoming BPF
open-coded iterators allowing for less restrictive looping capabilities,
from Andrii Nakryiko.
3) Rework RCU enforcement in the verifier, add kptr_rcu and enforce BPF
programs to NULL-check before passing such pointers into kfunc,
from Alexei Starovoitov.
4) Add support for kptrs in percpu hashmaps, percpu LRU hashmaps and in
local storage maps, from Kumar Kartikeya Dwivedi.
5) Add BPF verifier support for ST instructions in convert_ctx_access()
which will help new -mcpu=v4 clang flag to start emitting them,
from Eduard Zingerman.
6) Make uprobe attachment Android APK aware by supporting attachment
to functions inside ELF objects contained in APKs via function names,
from Daniel Müller.
7) Add a new flag BPF_F_TIMER_ABS flag for bpf_timer_start() helper
to start the timer with absolute expiration value instead of relative
one, from Tero Kristo.
8) Add a new kfunc bpf_cgroup_from_id() to look up cgroups via id,
from Tejun Heo.
9) Extend libbpf to support users manually attaching kprobes/uprobes
in the legacy/perf/link mode, from Menglong Dong.
10) Implement workarounds in the mips BPF JIT for DADDI/R4000,
from Jiaxun Yang.
11) Enable mixing bpf2bpf and tailcalls for the loongarch BPF JIT,
from Hengqi Chen.
12) Extend BPF instruction set doc with describing the encoding of BPF
instructions in terms of how bytes are stored under big/little endian,
from Jose E. Marchesi.
13) Follow-up to enable kfunc support for riscv BPF JIT, from Pu Lehui.
14) Fix bpf_xdp_query() backwards compatibility on old kernels,
from Yonghong Song.
15) Fix BPF selftest cross compilation with CLANG_CROSS_FLAGS,
from Florent Revest.
16) Improve bpf_cpumask_ma to only allocate one bpf_mem_cache,
from Hou Tao.
17) Fix BPF verifier's check_subprogs to not unnecessarily mark
a subprogram with has_tail_call, from Ilya Leoshkevich.
18) Fix arm syscall regs spec in libbpf's bpf_tracing.h, from Puranjay Mohan.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (85 commits)
selftests/bpf: Add test for legacy/perf kprobe/uprobe attach mode
selftests/bpf: Split test_attach_probe into multi subtests
libbpf: Add support to set kprobe/uprobe attach mode
tools/resolve_btfids: Add /libsubcmd to .gitignore
bpf: add support for fixed-size memory pointer returns for kfuncs
bpf: generalize dynptr_get_spi to be usable for iters
bpf: mark PTR_TO_MEM as non-null register type
bpf: move kfunc_call_arg_meta higher in the file
bpf: ensure that r0 is marked scratched after any function call
bpf: fix visit_insn()'s detection of BPF_FUNC_timer_set_callback helper
bpf: clean up visit_insn()'s instruction processing
selftests/bpf: adjust log_fixup's buffer size for proper truncation
bpf: honor env->test_state_freq flag in is_state_visited()
selftests/bpf: enhance align selftest's expected log matching
bpf: improve regsafe() checks for PTR_TO_{MEM,BUF,TP_BUFFER}
bpf: improve stack slot state printing
selftests/bpf: Disassembler tests for verifier.c:convert_ctx_access()
selftests/bpf: test if pointer type is tracked for BPF_ST_MEM
bpf: allow ctx writes using BPF_ST_MEM instruction
bpf: Use separate RCU callbacks for freeing selem
...
====================
Link: https://lore.kernel.org/r/20230307004346.27578-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Daniel Borkmann says:
====================
pull-request: bpf 2023-03-06
We've added 8 non-merge commits during the last 7 day(s) which contain
a total of 9 files changed, 64 insertions(+), 18 deletions(-).
The main changes are:
1) Fix BTF resolver for DATASEC sections when a VAR points at a modifier,
that is, keep resolving such instances instead of bailing out,
from Lorenz Bauer.
2) Fix BPF test framework with regards to xdp_frame info misplacement
in the "live packet" code, from Alexander Lobakin.
3) Fix an infinite loop in BPF sockmap code for TCP/UDP/AF_UNIX,
from Liu Jian.
4) Fix a build error for riscv BPF JIT under PERF_EVENTS=n,
from Randy Dunlap.
5) Several BPF doc fixes with either broken links or external instead
of internal doc links, from Bagas Sanjaya.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
selftests/bpf: check that modifier resolves after pointer
btf: fix resolving BTF_KIND_VAR after ARRAY, STRUCT, UNION, PTR
bpf, test_run: fix &xdp_frame misplacement for LIVE_FRAMES
bpf, doc: Link to submitting-patches.rst for general patch submission info
bpf, doc: Do not link to docs.kernel.org for kselftest link
bpf, sockmap: Fix an infinite loop error when len is 0 in tcp_bpf_recvmsg_parser()
riscv, bpf: Fix patch_text implicit declaration
bpf, docs: Fix link to BTF doc
====================
Link: https://lore.kernel.org/r/20230306215944.11981-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
btf_datasec_resolve contains a bug that causes the following BTF
to fail loading:
[1] DATASEC a size=2 vlen=2
type_id=4 offset=0 size=1
type_id=7 offset=1 size=1
[2] INT (anon) size=1 bits_offset=0 nr_bits=8 encoding=(none)
[3] PTR (anon) type_id=2
[4] VAR a type_id=3 linkage=0
[5] INT (anon) size=1 bits_offset=0 nr_bits=8 encoding=(none)
[6] TYPEDEF td type_id=5
[7] VAR b type_id=6 linkage=0
This error message is printed during btf_check_all_types:
[1] DATASEC a size=2 vlen=2
type_id=7 offset=1 size=1 Invalid type
By tracing btf_*_resolve we can pinpoint the problem:
btf_datasec_resolve(depth: 1, type_id: 1, mode: RESOLVE_TBD) = 0
btf_var_resolve(depth: 2, type_id: 4, mode: RESOLVE_TBD) = 0
btf_ptr_resolve(depth: 3, type_id: 3, mode: RESOLVE_PTR) = 0
btf_var_resolve(depth: 2, type_id: 4, mode: RESOLVE_PTR) = 0
btf_datasec_resolve(depth: 1, type_id: 1, mode: RESOLVE_PTR) = -22
The last invocation of btf_datasec_resolve should invoke btf_var_resolve
by means of env_stack_push, instead it returns EINVAL. The reason is that
env_stack_push is never executed for the second VAR.
if (!env_type_is_resolve_sink(env, var_type) &&
!env_type_is_resolved(env, var_type_id)) {
env_stack_set_next_member(env, i + 1);
return env_stack_push(env, var_type, var_type_id);
}
env_type_is_resolve_sink() changes its behaviour based on resolve_mode.
For RESOLVE_PTR, we can simplify the if condition to the following:
(btf_type_is_modifier() || btf_type_is_ptr) && !env_type_is_resolved()
Since we're dealing with a VAR the clause evaluates to false. This is
not sufficient to trigger the bug however. The log output and EINVAL
are only generated if btf_type_id_size() fails.
if (!btf_type_id_size(btf, &type_id, &type_size)) {
btf_verifier_log_vsi(env, v->t, vsi, "Invalid type");
return -EINVAL;
}
Most types are sized, so for example a VAR referring to an INT is not a
problem. The bug is only triggered if a VAR points at a modifier. Since
we skipped btf_var_resolve that modifier was also never resolved, which
means that btf_resolved_type_id returns 0 aka VOID for the modifier.
This in turn causes btf_type_id_size to return NULL, triggering EINVAL.
To summarise, the following conditions are necessary:
- VAR pointing at PTR, STRUCT, UNION or ARRAY
- Followed by a VAR pointing at TYPEDEF, VOLATILE, CONST, RESTRICT or
TYPE_TAG
The fix is to reset resolve_mode to RESOLVE_TBD before attempting to
resolve a VAR from a DATASEC.
Fixes: 1dc9285184 ("bpf: kernel side support for BTF Var and DataSec")
Signed-off-by: Lorenz Bauer <lmb@isovalent.com>
Link: https://lore.kernel.org/r/20230306112138.155352-2-lmb@isovalent.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Support direct fixed-size (and for now, read-only) memory access when
kfunc's return type is a pointer to non-struct type. Calculate type size
and let BPF program access that many bytes directly. This is crucial for
numbers iterator.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230302235015.2044271-13-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Generalize the logic of fetching special stack slot object state using
spi (stack slot index). This will be used by STACK_ITER logic next.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230302235015.2044271-12-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
PTR_TO_MEM register without PTR_MAYBE_NULL is indeed non-null. This is
important for BPF verifier to be able to prune guaranteed not to be
taken branches. This is always the case with open-coded iterators.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230302235015.2044271-11-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Move struct bpf_kfunc_call_arg_meta higher in the file and put it next
to struct bpf_call_arg_meta, so it can be used from more functions.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230302235015.2044271-10-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
r0 is important (unless called function is void-returning, but that's
taken care of by print_verifier_state() anyways) in verifier logs.
Currently for helpers we seem to print it in verifier log, but for
kfuncs we don't.
Instead of figuring out where in the maze of code we accidentally set r0
as scratched for helpers and why we don't do that for kfuncs, just
enforce that after any function call r0 is marked as scratched.
Also, perhaps, we should reconsider "scratched" terminology, as it's
mightily confusing. "Touched" would seem more appropriate. But I left
that for follow ups for now.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230302235015.2044271-9-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
It's not correct to assume that any BPF_CALL instruction is a helper
call. Fix visit_insn()'s detection of bpf_timer_set_callback() helper by
also checking insn->code == 0. For kfuncs insn->code would be set to
BPF_PSEUDO_KFUNC_CALL, and for subprog calls it will be BPF_PSEUDO_CALL.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230302235015.2044271-8-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Instead of referencing processed instruction repeatedly as insns[t]
throughout entire visit_insn() function, take a local insn pointer and
work with it in a cleaner way.
It makes enhancing this function further a bit easier as well.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230302235015.2044271-7-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
env->test_state_freq flag can be set by user by passing
BPF_F_TEST_STATE_FREQ program flag. This is used in a bunch of selftests
to have predictable state checkpoints at every jump and so on.
Currently, bounded loop handling heuristic ignores this flag if number
of processed jumps and/or number of processed instructions is below some
thresholds, which throws off that reliable state checkpointing.
Honor this flag in all circumstances by disabling heuristic if
env->test_state_freq is set.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230302235015.2044271-5-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Teach regsafe() logic to handle PTR_TO_MEM, PTR_TO_BUF, and
PTR_TO_TP_BUFFER similarly to PTR_TO_MAP_{KEY,VALUE}. That is, instead of
exact match for var_off and range, use tnum_in() and range_within()
checks, allowing more general verified state to subsume more specific
current state. This allows to match wider range of valid and safe
states, speeding up verification and detecting wider range of equivalent
states for upcoming open-coded iteration looping logic.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230302235015.2044271-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Improve stack slot state printing to provide more useful and relevant
information, especially for dynptrs. While previously we'd see something
like:
8: (85) call bpf_ringbuf_reserve_dynptr#198 ; R0_w=scalar() fp-8_w=dddddddd fp-16_w=dddddddd refs=2
Now we'll see way more useful:
8: (85) call bpf_ringbuf_reserve_dynptr#198 ; R0_w=scalar() fp-16_w=dynptr_ringbuf(ref_id=2) refs=2
I experimented with printing the range of slots taken by dynptr,
something like:
fp-16..8_w=dynptr_ringbuf(ref_id=2)
But it felt very awkward and pretty useless. So we print the lowest
address (most negative offset) only.
The general structure of this code is now also set up for easier
extension and will accommodate ITER slots naturally.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230302235015.2044271-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Lift verifier restriction to use BPF_ST_MEM instructions to write to
context data structures. This requires the following changes:
- verifier.c:do_check() for BPF_ST updated to:
- no longer forbid writes to registers of type PTR_TO_CTX;
- track dst_reg type in the env->insn_aux_data[...].ptr_type field
(same way it is done for BPF_STX and BPF_LDX instructions).
- verifier.c:convert_ctx_access() and various callbacks invoked by
it are updated to handled BPF_ST instruction alongside BPF_STX.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230304011247.566040-2-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Martin suggested that instead of using a byte in the hole (which he has
a use for in his future patch) in bpf_local_storage_elem, we can
dispatch a different call_rcu callback based on whether we need to free
special fields in bpf_local_storage_elem data. The free path, described
in commit 9db44fdd81 ("bpf: Support kptrs in local storage maps"),
only waits for call_rcu callbacks when there are special (kptrs, etc.)
fields in the map value, hence it is necessary that we only access
smap in this case.
Therefore, dispatch different RCU callbacks based on the BPF map has a
valid btf_record, which dereference and use smap's btf_record only when
it is valid.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230303141542.300068-1-memxor@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
bpf_rcu_read_lock/unlock() are only available in clang compiled kernels. Lack
of such key mechanism makes it impossible for sleepable bpf programs to use RCU
pointers.
Allow bpf_rcu_read_lock/unlock() in GCC compiled kernels (though GCC doesn't
support btf_type_tag yet) and allowlist certain field dereferences in important
data structures like tast_struct, cgroup, socket that are used by sleepable
programs either as RCU pointer or full trusted pointer (which is valid outside
of RCU CS). Use BTF_TYPE_SAFE_RCU and BTF_TYPE_SAFE_TRUSTED macros for such
tagging. They will be removed once GCC supports btf_type_tag.
With that refactor check_ptr_to_btf_access(). Make it strict in enforcing
PTR_TRUSTED and PTR_UNTRUSTED while deprecating old PTR_TO_BTF_ID without
modifier flags. There is a chance that this strict enforcement might break
existing programs (especially on GCC compiled kernels), but this cleanup has to
start sooner than later. Note PTR_TO_CTX access still yields old deprecated
PTR_TO_BTF_ID. Once it's converted to strict PTR_TRUSTED or PTR_UNTRUSTED the
kfuncs and helpers will be able to default to KF_TRUSTED_ARGS. KF_RCU will
remain as a weaker version of KF_TRUSTED_ARGS where obj refcnt could be 0.
Adjust rcu_read_lock selftest to run on gcc and clang compiled kernels.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/bpf/20230303041446.3630-7-alexei.starovoitov@gmail.com
The life time of certain kernel structures like 'struct cgroup' is protected by RCU.
Hence it's safe to dereference them directly from __kptr tagged pointers in bpf maps.
The resulting pointer is MEM_RCU and can be passed to kfuncs that expect KF_RCU.
Derefrence of other kptr-s returns PTR_UNTRUSTED.
For example:
struct map_value {
struct cgroup __kptr *cgrp;
};
SEC("tp_btf/cgroup_mkdir")
int BPF_PROG(test_cgrp_get_ancestors, struct cgroup *cgrp_arg, const char *path)
{
struct cgroup *cg, *cg2;
cg = bpf_cgroup_acquire(cgrp_arg); // cg is PTR_TRUSTED and ref_obj_id > 0
bpf_kptr_xchg(&v->cgrp, cg);
cg2 = v->cgrp; // This is new feature introduced by this patch.
// cg2 is PTR_MAYBE_NULL | MEM_RCU.
// When cg2 != NULL, it's a valid cgroup, but its percpu_ref could be zero
if (cg2)
bpf_cgroup_ancestor(cg2, level); // safe to do.
}
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/bpf/20230303041446.3630-4-alexei.starovoitov@gmail.com
bpf programs sometimes do:
bpf_cgrp_storage_get(&map, task->cgroups->dfl_cgrp, ...);
It is safe to do, because cgroups->dfl_cgrp pointer is set diring init and
never changes. The task->cgroups is also never NULL. It is also set during init
and will change when task switches cgroups. For any trusted task pointer
dereference of cgroups and dfl_cgrp should yield trusted pointers. The verifier
wasn't aware of this. Hence in gcc compiled kernels task->cgroups dereference
was producing PTR_TO_BTF_ID without modifiers while in clang compiled kernels
the verifier recognizes __rcu tag in cgroups field and produces
PTR_TO_BTF_ID | MEM_RCU | MAYBE_NULL.
Tag cgroups and dfl_cgrp as trusted to equalize clang and gcc behavior.
When GCC supports btf_type_tag such tagging will done directly in the type.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: David Vernet <void@manifault.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/bpf/20230303041446.3630-3-alexei.starovoitov@gmail.com
__kptr meant to store PTR_UNTRUSTED kernel pointers inside bpf maps.
The concept felt useful, but didn't get much traction,
since bpf_rdonly_cast() was added soon after and bpf programs received
a simpler way to access PTR_UNTRUSTED kernel pointers
without going through restrictive __kptr usage.
Rename __kptr_ref -> __kptr and __kptr -> __kptr_untrusted to indicate
its intended usage.
The main goal of __kptr_untrusted was to read/write such pointers
directly while bpf_kptr_xchg was a mechanism to access refcnted
kernel pointers. The next patch will allow RCU protected __kptr access
with direct read. At that point __kptr_untrusted will be deprecated.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/bpf/20230303041446.3630-2-alexei.starovoitov@gmail.com
Add a new flag BPF_F_TIMER_ABS that can be passed to bpf_timer_start()
to start an absolute value timer instead of the default relative value.
This makes the timer expire at an exact point in time, instead of a time
with latencies induced by both the BPF and timer subsystems.
Suggested-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Tero Kristo <tero.kristo@linux.intel.com>
Link: https://lore.kernel.org/r/20230302114614.2985072-2-tero.kristo@linux.intel.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
These helpers are safe to call from any context and there's no reason to
restrict access to them. Remove them from bpf_trace and filter lists and add
to bpf_base_func_proto() under perfmon_capable().
v2: After consulting with Andrii, relocated in bpf_base_func_proto() so that
they require bpf_capable() but not perfomon_capable() as it doesn't read
from or affect others on the system.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/ZAD8QyoszMZiTzBY@slm.duckdns.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Change bpf_dynptr_slice and bpf_dynptr_slice_rdwr to return NULL instead
of 0, in accordance with the codebase guidelines.
Fixes: 66e3a13e7c ("bpf: Add bpf_dynptr_slice and bpf_dynptr_slice_rdwr")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230302053014.1726219-1-joannelkoong@gmail.com
In commit 66e3a13e7c ("bpf: Add bpf_dynptr_slice and
bpf_dynptr_slice_rdwr"), the bpf_dynptr_slice() and
bpf_dynptr_slice_rdwr() kfuncs were added to BPF. These kfuncs included
doxygen headers, but unfortunately those headers are not properly
formatted according to [0], and causes the following warnings during the
docs build:
./kernel/bpf/helpers.c:2225: warning: \
Excess function parameter 'returns' description in 'bpf_dynptr_slice'
./kernel/bpf/helpers.c:2303: warning: \
Excess function parameter 'returns' description in 'bpf_dynptr_slice_rdwr'
...
This patch fixes those doxygen comments.
[0]: https://docs.kernel.org/doc-guide/kernel-doc.html#function-documentation
Fixes: 66e3a13e7c ("bpf: Add bpf_dynptr_slice and bpf_dynptr_slice_rdwr")
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230301194910.602738-1-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Enable support for kptrs in local storage maps by wiring up the freeing
of these kptrs from map value. Freeing of bpf_local_storage_map is only
delayed in case there are special fields, therefore bpf_selem_free_*
path can also only dereference smap safely in that case. This is
recorded using a bool utilizing a hole in bpF_local_storage_elem. It
could have been tagged in the pointer value smap using the lowest bit
(since alignment > 1), but since there was already a hole I went with
the simpler option. Only the map structure freeing is delayed using RCU
barriers, as the buckets aren't used when selem is being freed, so they
can be freed once all readers of the bucket lists can no longer access
it.
Cc: Martin KaFai Lau <martin.lau@kernel.org>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230225154010.391965-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Enable support for kptrs in percpu BPF hashmap and percpu BPF LRU
hashmap by wiring up the freeing of these kptrs from percpu map
elements.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230225154010.391965-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Two new kfuncs are added, bpf_dynptr_slice and bpf_dynptr_slice_rdwr.
The user must pass in a buffer to store the contents of the data slice
if a direct pointer to the data cannot be obtained.
For skb and xdp type dynptrs, these two APIs are the only way to obtain
a data slice. However, for other types of dynptrs, there is no
difference between bpf_dynptr_slice(_rdwr) and bpf_dynptr_data.
For skb type dynptrs, the data is copied into the user provided buffer
if any of the data is not in the linear portion of the skb. For xdp type
dynptrs, the data is copied into the user provided buffer if the data is
between xdp frags.
If the skb is cloned and a call to bpf_dynptr_data_rdwr is made, then
the skb will be uncloned (see bpf_unclone_prologue()).
Please note that any bpf_dynptr_write() automatically invalidates any prior
data slices of the skb dynptr. This is because the skb may be cloned or
may need to pull its paged buffer into the head. As such, any
bpf_dynptr_write() will automatically have its prior data slices
invalidated, even if the write is to data in the skb head of an uncloned
skb. Please note as well that any other helper calls that change the
underlying packet buffer (eg bpf_skb_pull_data()) invalidates any data
slices of the skb dynptr as well, for the same reasons.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Link: https://lore.kernel.org/r/20230301154953.641654-10-joannelkoong@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add xdp dynptrs, which are dynptrs whose underlying pointer points
to a xdp_buff. The dynptr acts on xdp data. xdp dynptrs have two main
benefits. One is that they allow operations on sizes that are not
statically known at compile-time (eg variable-sized accesses).
Another is that parsing the packet data through dynptrs (instead of
through direct access of xdp->data and xdp->data_end) can be more
ergonomic and less brittle (eg does not need manual if checking for
being within bounds of data_end).
For reads and writes on the dynptr, this includes reading/writing
from/to and across fragments. Data slices through the bpf_dynptr_data
API are not supported; instead bpf_dynptr_slice() and
bpf_dynptr_slice_rdwr() should be used.
For examples of how xdp dynptrs can be used, please see the attached
selftests.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Link: https://lore.kernel.org/r/20230301154953.641654-9-joannelkoong@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add skb dynptrs, which are dynptrs whose underlying pointer points
to a skb. The dynptr acts on skb data. skb dynptrs have two main
benefits. One is that they allow operations on sizes that are not
statically known at compile-time (eg variable-sized accesses).
Another is that parsing the packet data through dynptrs (instead of
through direct access of skb->data and skb->data_end) can be more
ergonomic and less brittle (eg does not need manual if checking for
being within bounds of data_end).
For bpf prog types that don't support writes on skb data, the dynptr is
read-only (bpf_dynptr_write() will return an error)
For reads and writes through the bpf_dynptr_read() and bpf_dynptr_write()
interfaces, reading and writing from/to data in the head as well as from/to
non-linear paged buffers is supported. Data slices through the
bpf_dynptr_data API are not supported; instead bpf_dynptr_slice() and
bpf_dynptr_slice_rdwr() (added in subsequent commit) should be used.
For examples of how skb dynptrs can be used, please see the attached
selftests.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Link: https://lore.kernel.org/r/20230301154953.641654-8-joannelkoong@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch adds __uninit as a kfunc annotation.
This will be useful for scenarios such as for example in dynptrs,
indicating whether the dynptr should be checked by the verifier as an
initialized or an uninitialized dynptr.
Without this annotation, the alternative would be needing to hard-code
in the verifier the specific kfunc to indicate that arg should be
treated as an uninitialized arg.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Link: https://lore.kernel.org/r/20230301154953.641654-7-joannelkoong@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit refactors the logic for determining which register in a
function is the dynptr into "get_dynptr_arg_reg". This will be used
in the future when the dynptr reg for BPF_FUNC_dynptr_write will need
to be obtained in order to support writes for skb dynptrs.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Link: https://lore.kernel.org/r/20230301154953.641654-6-joannelkoong@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This change allows kfuncs to take in an uninitialized dynptr as a
parameter. Before this change, only helper functions could successfully
use uninitialized dynptrs. This change moves the memory access check
(including stack state growing and slot marking) into
process_dynptr_func(), which both helpers and kfuncs call into.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Link: https://lore.kernel.org/r/20230301154953.641654-4-joannelkoong@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This change cleans up process_dynptr_func's flow to be more intuitive
and updates some comments with more context.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Link: https://lore.kernel.org/r/20230301154953.641654-3-joannelkoong@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The bpf mirror of the in-kernel sk_buff and xdp_buff data structures are
__sk_buff and xdp_md. Currently, when we pass in the program ctx to a
kfunc where the program ctx is a skb or xdp buffer, we reject the
program if the in-kernel definition is sk_buff/xdp_buff instead of
__sk_buff/xdp_md.
This change allows "sk_buff <--> __sk_buff" and "xdp_buff <--> xdp_md"
to be recognized as valid matches. The user program may pass in their
program ctx as a __sk_buff or xdp_md, and the in-kernel definition
of the kfunc may define this arg as a sk_buff or xdp_buff.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Link: https://lore.kernel.org/r/20230301154953.641654-2-joannelkoong@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In commit 332ea1f697 ("bpf: Add bpf_cgroup_from_id() kfunc"), a new
bpf_cgroup_from_id() kfunc was added which allows a BPF program to
lookup and acquire a reference to a cgroup from a cgroup id. The
commit's doxygen comment seems to have copy-pasted fields, which causes
BPF kfunc helper documentation to fail to render:
<snip>/helpers.c:2114: warning: Excess function parameter 'cgrp'...
<snip>/helpers.c:2114: warning: Excess function parameter 'level'...
<snip>
<snip>/helpers.c:2114: warning: Excess function parameter 'level'...
This patch fixes the doxygen header.
Fixes: 332ea1f697 ("bpf: Add bpf_cgroup_from_id() kfunc")
Signed-off-by: David Vernet <void@manifault.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20230228152845.294695-1-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
F_SEAL_EXEC") which permits the setting of the memfd execute bit at
memfd creation time, with the option of sealing the state of the X bit.
- Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset()
thread-safe for pmd unshare") which addresses a rare race condition
related to PMD unsharing.
- Several folioification patch serieses from Matthew Wilcox, Vishal
Moola, Sidhartha Kumar and Lorenzo Stoakes
- Johannes Weiner has a series ("mm: push down lock_page_memcg()") which
does perform some memcg maintenance and cleanup work.
- SeongJae Park has added DAMOS filtering to DAMON, with the series
"mm/damon/core: implement damos filter". These filters provide users
with finer-grained control over DAMOS's actions. SeongJae has also done
some DAMON cleanup work.
- Kairui Song adds a series ("Clean up and fixes for swap").
- Vernon Yang contributed the series "Clean up and refinement for maple
tree".
- Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It
adds to MGLRU an LRU of memcgs, to improve the scalability of global
reclaim.
- David Hildenbrand has added some userfaultfd cleanup work in the
series "mm: uffd-wp + change_protection() cleanups".
- Christoph Hellwig has removed the generic_writepages() library
function in the series "remove generic_writepages".
- Baolin Wang has performed some maintenance on the compaction code in
his series "Some small improvements for compaction".
- Sidhartha Kumar is doing some maintenance work on struct page in his
series "Get rid of tail page fields".
- David Hildenbrand contributed some cleanup, bugfixing and
generalization of pte management and of pte debugging in his series "mm:
support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with swap
PTEs".
- Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation
flag in the series "Discard __GFP_ATOMIC".
- Sergey Senozhatsky has improved zsmalloc's memory utilization with his
series "zsmalloc: make zspage chain size configurable".
- Joey Gouly has added prctl() support for prohibiting the creation of
writeable+executable mappings. The previous BPF-based approach had
shortcomings. See "mm: In-kernel support for memory-deny-write-execute
(MDWE)".
- Waiman Long did some kmemleak cleanup and bugfixing in the series
"mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF".
- T.J. Alumbaugh has contributed some MGLRU cleanup work in his series
"mm: multi-gen LRU: improve".
- Jiaqi Yan has provided some enhancements to our memory error
statistics reporting, mainly by presenting the statistics on a per-node
basis. See the series "Introduce per NUMA node memory error
statistics".
- Mel Gorman has a second and hopefully final shot at fixing a CPU-hog
regression in compaction via his series "Fix excessive CPU usage during
compaction".
- Christoph Hellwig does some vmalloc maintenance work in the series
"cleanup vfree and vunmap".
- Christoph Hellwig has removed block_device_operations.rw_page() in ths
series "remove ->rw_page".
- We get some maple_tree improvements and cleanups in Liam Howlett's
series "VMA tree type safety and remove __vma_adjust()".
- Suren Baghdasaryan has done some work on the maintainability of our
vm_flags handling in the series "introduce vm_flags modifier functions".
- Some pagemap cleanup and generalization work in Mike Rapoport's series
"mm, arch: add generic implementation of pfn_valid() for FLATMEM" and
"fixups for generic implementation of pfn_valid()"
- Baoquan He has done some work to make /proc/vmallocinfo and
/proc/kcore better represent the real state of things in his series
"mm/vmalloc.c: allow vread() to read out vm_map_ram areas".
- Jason Gunthorpe rationalized the GUP system's interface to the rest of
the kernel in the series "Simplify the external interface for GUP".
- SeongJae Park wishes to migrate people from DAMON's debugfs interface
over to its sysfs interface. To support this, we'll temporarily be
printing warnings when people use the debugfs interface. See the series
"mm/damon: deprecate DAMON debugfs interface".
- Andrey Konovalov provided the accurately named "lib/stackdepot: fixes
and clean-ups" series.
- Huang Ying has provided a dramatic reduction in migration's TLB flush
IPI rates with the series "migrate_pages(): batch TLB flushing".
- Arnd Bergmann has some objtool fixups in "objtool warning fixes".
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Merge tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Daniel Verkamp has contributed a memfd series ("mm/memfd: add
F_SEAL_EXEC") which permits the setting of the memfd execute bit at
memfd creation time, with the option of sealing the state of the X
bit.
- Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset()
thread-safe for pmd unshare") which addresses a rare race condition
related to PMD unsharing.
- Several folioification patch serieses from Matthew Wilcox, Vishal
Moola, Sidhartha Kumar and Lorenzo Stoakes
- Johannes Weiner has a series ("mm: push down lock_page_memcg()")
which does perform some memcg maintenance and cleanup work.
- SeongJae Park has added DAMOS filtering to DAMON, with the series
"mm/damon/core: implement damos filter".
These filters provide users with finer-grained control over DAMOS's
actions. SeongJae has also done some DAMON cleanup work.
- Kairui Song adds a series ("Clean up and fixes for swap").
- Vernon Yang contributed the series "Clean up and refinement for maple
tree".
- Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It
adds to MGLRU an LRU of memcgs, to improve the scalability of global
reclaim.
- David Hildenbrand has added some userfaultfd cleanup work in the
series "mm: uffd-wp + change_protection() cleanups".
- Christoph Hellwig has removed the generic_writepages() library
function in the series "remove generic_writepages".
- Baolin Wang has performed some maintenance on the compaction code in
his series "Some small improvements for compaction".
- Sidhartha Kumar is doing some maintenance work on struct page in his
series "Get rid of tail page fields".
- David Hildenbrand contributed some cleanup, bugfixing and
generalization of pte management and of pte debugging in his series
"mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with
swap PTEs".
- Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation
flag in the series "Discard __GFP_ATOMIC".
- Sergey Senozhatsky has improved zsmalloc's memory utilization with
his series "zsmalloc: make zspage chain size configurable".
- Joey Gouly has added prctl() support for prohibiting the creation of
writeable+executable mappings.
The previous BPF-based approach had shortcomings. See "mm: In-kernel
support for memory-deny-write-execute (MDWE)".
- Waiman Long did some kmemleak cleanup and bugfixing in the series
"mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF".
- T.J. Alumbaugh has contributed some MGLRU cleanup work in his series
"mm: multi-gen LRU: improve".
- Jiaqi Yan has provided some enhancements to our memory error
statistics reporting, mainly by presenting the statistics on a
per-node basis. See the series "Introduce per NUMA node memory error
statistics".
- Mel Gorman has a second and hopefully final shot at fixing a CPU-hog
regression in compaction via his series "Fix excessive CPU usage
during compaction".
- Christoph Hellwig does some vmalloc maintenance work in the series
"cleanup vfree and vunmap".
- Christoph Hellwig has removed block_device_operations.rw_page() in
ths series "remove ->rw_page".
- We get some maple_tree improvements and cleanups in Liam Howlett's
series "VMA tree type safety and remove __vma_adjust()".
- Suren Baghdasaryan has done some work on the maintainability of our
vm_flags handling in the series "introduce vm_flags modifier
functions".
- Some pagemap cleanup and generalization work in Mike Rapoport's
series "mm, arch: add generic implementation of pfn_valid() for
FLATMEM" and "fixups for generic implementation of pfn_valid()"
- Baoquan He has done some work to make /proc/vmallocinfo and
/proc/kcore better represent the real state of things in his series
"mm/vmalloc.c: allow vread() to read out vm_map_ram areas".
- Jason Gunthorpe rationalized the GUP system's interface to the rest
of the kernel in the series "Simplify the external interface for
GUP".
- SeongJae Park wishes to migrate people from DAMON's debugfs interface
over to its sysfs interface. To support this, we'll temporarily be
printing warnings when people use the debugfs interface. See the
series "mm/damon: deprecate DAMON debugfs interface".
- Andrey Konovalov provided the accurately named "lib/stackdepot: fixes
and clean-ups" series.
- Huang Ying has provided a dramatic reduction in migration's TLB flush
IPI rates with the series "migrate_pages(): batch TLB flushing".
- Arnd Bergmann has some objtool fixups in "objtool warning fixes".
* tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (505 commits)
include/linux/migrate.h: remove unneeded externs
mm/memory_hotplug: cleanup return value handing in do_migrate_range()
mm/uffd: fix comment in handling pte markers
mm: change to return bool for isolate_movable_page()
mm: hugetlb: change to return bool for isolate_hugetlb()
mm: change to return bool for isolate_lru_page()
mm: change to return bool for folio_isolate_lru()
objtool: add UACCESS exceptions for __tsan_volatile_read/write
kmsan: disable ftrace in kmsan core code
kasan: mark addr_has_metadata __always_inline
mm: memcontrol: rename memcg_kmem_enabled()
sh: initialize max_mapnr
m68k/nommu: add missing definition of ARCH_PFN_OFFSET
mm: percpu: fix incorrect size in pcpu_obj_full_size()
maple_tree: reduce stack usage with gcc-9 and earlier
mm: page_alloc: call panic() when memoryless node allocation fails
mm: multi-gen LRU: avoid futile retries
migrate_pages: move THP/hugetlb migration support check to simplify code
migrate_pages: batch flushing TLB
migrate_pages: share more code between _unmap and _move
...
cgroup ID is an userspace-visible 64bit value uniquely identifying a given
cgroup. As the IDs are used widely, it's useful to be able to look up the
matching cgroups. Add bpf_cgroup_from_id().
v2: Separate out selftest into its own patch as suggested by Alexei.
Signed-off-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/Y/bBaG96t0/gQl9/@slm.duckdns.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The condition src_reg != BPF_PSEUDO_CALL && imm == BPF_FUNC_tail_call
may be satisfied by a kfunc call. This would lead to unnecessarily
setting has_tail_call. Use src_reg == 0 instead.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230220163756.753713-1-iii@linux.ibm.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The size of bpf_cpumask is fixed, so there is no need to allocate many
bpf_mem_caches for bpf_cpumask_ma, just one bpf_mem_cache is enough.
Also add comments for bpf_mem_alloc_init() in bpf_mem_alloc.h to prevent
future miuse.
Signed-off-by: Hou Tao <houtao1@huawei.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230216024821.2202916-1-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Typically, verifier should use env->allow_ptr_leaks when invaliding
registers for users that don't have CAP_PERFMON or CAP_SYS_ADMIN to
avoid leaking the pointer value. This is similar in spirit to
c67cae551f ("bpf: Tighten ptr_to_btf_id checks."). In a lot of the
existing checks, we know the capabilities are present, hence we don't do
the check.
Instead of being inconsistent in the application of the check, wrap the
action of invalidating a register into a helper named 'mark_invalid_reg'
and use it in a uniform fashion to replace open coded invalidation
operations, so that the check is always made regardless of the call site
and we don't have to remember whether it needs to be done or not for
each case.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230221200646.2500777-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The current code does type matching for the case where reg->type is
PTR_TO_BTF_ID or has the PTR_TRUSTED flag. However, this only needs to
occur for non-MEM_ALLOC and non-MEM_PERCPU cases, but will include both
as per the current code.
The MEM_ALLOC case with or without PTR_TRUSTED needs to be handled
specially by the code for type_is_alloc case, while MEM_PERCPU case must
be ignored. Hence, to restore correct behavior and for clarity,
explicitly list out the handled PTR_TO_BTF_ID types which should be
handled for each case using a switch statement.
Helpers currently only take:
PTR_TO_BTF_ID
PTR_TO_BTF_ID | PTR_TRUSTED
PTR_TO_BTF_ID | MEM_RCU
PTR_TO_BTF_ID | MEM_ALLOC
PTR_TO_BTF_ID | MEM_PERCPU
PTR_TO_BTF_ID | MEM_PERCPU | PTR_TRUSTED
This fix was also described (for the MEM_ALLOC case) in [0].
[0]: https://lore.kernel.org/bpf/20221121160657.h6z7xuvedybp5y7s@apollo
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230221200646.2500777-6-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The plan is to supposedly tag everything with PTR_TRUSTED eventually,
however those changes should bring in their respective code, instead
of leaving it around right now. It is arguable whether PTR_TRUSTED is
required for all types, when it's only use case is making PTR_TO_BTF_ID
a bit stronger, while all other types are trusted by default.
Hence, just drop the two instances which do not occur in the verifier
for now to avoid reader confusion.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230221200646.2500777-5-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
There are a few cases where hlist_node is checked to be unhashed without
holding the lock protecting its modification. In this case, one must use
hlist_unhashed_lockless to avoid load tearing and KCSAN reports. Fix
this by using lockless variant in places not protected by the lock.
Since this is not prompted by any actual KCSAN reports but only from
code review, I have not included a fixes tag.
Cc: Martin KaFai Lau <martin.lau@kernel.org>
Cc: KP Singh <kpsingh@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230221200646.2500777-4-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commits updates the following functions to allow reads from
uninitialized stack locations when env->allow_uninit_stack option is
enabled:
- check_stack_read_fixed_off()
- check_stack_range_initialized(), called from:
- check_stack_read_var_off()
- check_helper_mem_access()
Such change allows to relax logic in stacksafe() to treat STACK_MISC
and STACK_INVALID in a same way and make the following stack slot
configurations equivalent:
| Cached state | Current state |
| stack slot | stack slot |
|------------------+------------------|
| STACK_INVALID or | STACK_INVALID or |
| STACK_MISC | STACK_SPILL or |
| | STACK_MISC or |
| | STACK_ZERO or |
| | STACK_DYNPTR |
This leads to significant verification speed gains (see below).
The idea was suggested by Andrii Nakryiko [1] and initial patch was
created by Alexei Starovoitov [2].
Currently the env->allow_uninit_stack is allowed for programs loaded
by users with CAP_PERFMON or CAP_SYS_ADMIN capabilities.
A number of test cases from verifier/*.c were expecting uninitialized
stack access to be an error. These test cases were updated to execute
in unprivileged mode (thus preserving the tests).
The test progs/test_global_func10.c expected "invalid indirect read
from stack" error message because of the access to uninitialized
memory region. This error is no longer possible in privileged mode.
The test is updated to provoke an error "invalid indirect access to
stack" because of access to invalid stack address (such error is not
verified by progs/test_global_func*.c series of tests).
The following tests had to be removed because these can't be made
unprivileged:
- verifier/sock.c:
- "sk_storage_get(map, skb->sk, &stack_value, 1): partially init
stack_value"
BPF_PROG_TYPE_SCHED_CLS programs are not executed in unprivileged mode.
- verifier/var_off.c:
- "indirect variable-offset stack access, max_off+size > max_initialized"
- "indirect variable-offset stack access, uninitialized"
These tests verify that access to uninitialized stack values is
detected when stack offset is not a constant. However, variable
stack access is prohibited in unprivileged mode, thus these tests
are no longer valid.
* * *
Here is veristat log comparing this patch with current master on a
set of selftest binaries listed in tools/testing/selftests/bpf/veristat.cfg
and cilium BPF binaries (see [3]):
$ ./veristat -e file,prog,states -C -f 'states_pct<-30' master.log current.log
File Program States (A) States (B) States (DIFF)
-------------------------- -------------------------- ---------- ---------- ----------------
bpf_host.o tail_handle_ipv6_from_host 349 244 -105 (-30.09%)
bpf_host.o tail_handle_nat_fwd_ipv4 1320 895 -425 (-32.20%)
bpf_lxc.o tail_handle_nat_fwd_ipv4 1320 895 -425 (-32.20%)
bpf_sock.o cil_sock4_connect 70 48 -22 (-31.43%)
bpf_sock.o cil_sock4_sendmsg 68 46 -22 (-32.35%)
bpf_xdp.o tail_handle_nat_fwd_ipv4 1554 803 -751 (-48.33%)
bpf_xdp.o tail_lb_ipv4 6457 2473 -3984 (-61.70%)
bpf_xdp.o tail_lb_ipv6 7249 3908 -3341 (-46.09%)
pyperf600_bpf_loop.bpf.o on_event 287 145 -142 (-49.48%)
strobemeta.bpf.o on_event 15915 4772 -11143 (-70.02%)
strobemeta_nounroll2.bpf.o on_event 17087 3820 -13267 (-77.64%)
xdp_synproxy_kern.bpf.o syncookie_tc 21271 6635 -14636 (-68.81%)
xdp_synproxy_kern.bpf.o syncookie_xdp 23122 6024 -17098 (-73.95%)
-------------------------- -------------------------- ---------- ---------- ----------------
Note: I limited selection by states_pct<-30%.
Inspection of differences in pyperf600_bpf_loop behavior shows that
the following patch for the test removes almost all differences:
- a/tools/testing/selftests/bpf/progs/pyperf.h
+ b/tools/testing/selftests/bpf/progs/pyperf.h
@ -266,8 +266,8 @ int __on_event(struct bpf_raw_tracepoint_args *ctx)
}
if (event->pthread_match || !pidData->use_tls) {
- void* frame_ptr;
- FrameData frame;
+ void* frame_ptr = 0;
+ FrameData frame = {};
Symbol sym = {};
int cur_cpu = bpf_get_smp_processor_id();
W/o this patch the difference comes from the following pattern
(for different variables):
static bool get_frame_data(... FrameData *frame ...)
{
...
bpf_probe_read_user(&frame->f_code, ...);
if (!frame->f_code)
return false;
...
bpf_probe_read_user(&frame->co_name, ...);
if (frame->co_name)
...;
}
int __on_event(struct bpf_raw_tracepoint_args *ctx)
{
FrameData frame;
...
get_frame_data(... &frame ...) // indirectly via a bpf_loop & callback
...
}
SEC("raw_tracepoint/kfree_skb")
int on_event(struct bpf_raw_tracepoint_args* ctx)
{
...
ret |= __on_event(ctx);
ret |= __on_event(ctx);
...
}
With regards to value `frame->co_name` the following is important:
- Because of the conditional `if (!frame->f_code)` each call to
__on_event() produces two states, one with `frame->co_name` marked
as STACK_MISC, another with it as is (and marked STACK_INVALID on a
first call).
- The call to bpf_probe_read_user() does not mark stack slots
corresponding to `&frame->co_name` as REG_LIVE_WRITTEN but it marks
these slots as BPF_MISC, this happens because of the following loop
in the check_helper_call():
for (i = 0; i < meta.access_size; i++) {
err = check_mem_access(env, insn_idx, meta.regno, i, BPF_B,
BPF_WRITE, -1, false);
if (err)
return err;
}
Note the size of the write, it is a one byte write for each byte
touched by a helper. The BPF_B write does not lead to write marks
for the target stack slot.
- Which means that w/o this patch when second __on_event() call is
verified `if (frame->co_name)` will propagate read marks first to a
stack slot with STACK_MISC marks and second to a stack slot with
STACK_INVALID marks and these states would be considered different.
[1] https://lore.kernel.org/bpf/CAEf4BzY3e+ZuC6HUa8dCiUovQRg2SzEk7M-dSkqNZyn=xEmnPA@mail.gmail.com/
[2] https://lore.kernel.org/bpf/CAADnVQKs2i1iuZ5SUGuJtxWVfGYR9kDgYKhq3rNV+kBLQCu7rA@mail.gmail.com/
[3] git@github.com:anakryiko/cilium.git
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Co-developed-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230219200427.606541-2-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Commit 74e19ef0ff ("uaccess: Add speculation barrier to
copy_from_user()") built fine on x86-64 and arm64, and that's the extent
of my local build testing.
It turns out those got the <linux/nospec.h> include incidentally through
other header files (<linux/kvm_host.h> in particular), but that was not
true of other architectures, resulting in build errors
kernel/bpf/core.c: In function ‘___bpf_prog_run’:
kernel/bpf/core.c:1913:3: error: implicit declaration of function ‘barrier_nospec’
so just make sure to explicitly include the proper <linux/nospec.h>
header file to make everybody see it.
Fixes: 74e19ef0ff ("uaccess: Add speculation barrier to copy_from_user()")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Viresh Kumar <viresh.kumar@linaro.org>
Reported-by: Huacai Chen <chenhuacai@loongson.cn>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Core
----
- Add dedicated kmem_cache for typical/small skb->head, avoid having
to access struct page at kfree time, and improve memory use.
- Introduce sysctl to set default RPS configuration for new netdevs.
- Define Netlink protocol specification format which can be used
to describe messages used by each family and auto-generate parsers.
Add tools for generating kernel data structures and uAPI headers.
- Expose all net/core sysctls inside netns.
- Remove 4s sleep in netpoll if carrier is instantly detected on boot.
- Add configurable limit of MDB entries per port, and port-vlan.
- Continue populating drop reasons throughout the stack.
- Retire a handful of legacy Qdiscs and classifiers.
Protocols
---------
- Support IPv4 big TCP (TSO frames larger than 64kB).
- Add IP_LOCAL_PORT_RANGE socket option, to control local port range
on socket by socket basis.
- Track and report in procfs number of MPTCP sockets used.
- Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP
path manager.
- IPv6: don't check net.ipv6.route.max_size and rely on garbage
collection to free memory (similarly to IPv4).
- Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).
- ICMP: add per-rate limit counters.
- Add support for user scanning requests in ieee802154.
- Remove static WEP support.
- Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
reporting.
- WiFi 7 EHT channel puncturing support (client & AP).
BPF
---
- Add a rbtree data structure following the "next-gen data structure"
precedent set by recently added linked list, that is, by using
kfunc + kptr instead of adding a new BPF map type.
- Expose XDP hints via kfuncs with initial support for RX hash and
timestamp metadata.
- Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key
to better support decap on GRE tunnel devices not operating
in collect metadata.
- Improve x86 JIT's codegen for PROBE_MEM runtime error checks.
- Remove the need for trace_printk_lock for bpf_trace_printk
and bpf_trace_vprintk helpers.
- Extend libbpf's bpf_tracing.h support for tracing arguments of
kprobes/uprobes and syscall as a special case.
- Significantly reduce the search time for module symbols
by livepatch and BPF.
- Enable cpumasks to be used as kptrs, which is useful for tracing
programs tracking which tasks end up running on which CPUs in
different time intervals.
- Add support for BPF trampoline on s390x and riscv64.
- Add capability to export the XDP features supported by the NIC.
- Add __bpf_kfunc tag for marking kernel functions as kfuncs.
- Add cgroup.memory=nobpf kernel parameter option to disable BPF
memory accounting for container environments.
Netfilter
---------
- Remove the CLUSTERIP target. It has been marked as obsolete
for years, and we still have WARN splats wrt. races of
the out-of-band /proc interface installed by this target.
- Add 'destroy' commands to nf_tables. They are identical to
the existing 'delete' commands, but do not return an error if
the referenced object (set, chain, rule...) did not exist.
Driver API
----------
- Improve cpumask_local_spread() locality to help NICs set the right
IRQ affinity on AMD platforms.
- Separate C22 and C45 MDIO bus transactions more clearly.
- Introduce new DCB table to control DSCP rewrite on egress.
- Support configuration of Physical Layer Collision Avoidance (PLCA)
Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
shared medium Ethernet.
- Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
preemption of low priority frames by high priority frames.
- Add support for controlling MACSec offload using netlink SET.
- Rework devlink instance refcounts to allow registration and
de-registration under the instance lock. Split the code into multiple
files, drop some of the unnecessarily granular locks and factor out
common parts of netlink operation handling.
- Add TX frame aggregation parameters (for USB drivers).
- Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
messages with notifications for debug.
- Allow offloading of UDP NEW connections via act_ct.
- Add support for per action HW stats in TC.
- Support hardware miss to TC action (continue processing in SW from
a specific point in the action chain).
- Warn if old Wireless Extension user space interface is used with
modern cfg80211/mac80211 drivers. Do not support Wireless Extensions
for Wi-Fi 7 devices at all. Everyone should switch to using nl80211
interface instead.
- Improve the CAN bit timing configuration. Use extack to return error
messages directly to user space, update the SJW handling, including
the definition of a new default value that will benefit CAN-FD
controllers, by increasing their oscillator tolerance.
New hardware / drivers
----------------------
- Ethernet:
- nVidia BlueField-3 support (control traffic driver)
- Ethernet support for imx93 SoCs
- Motorcomm yt8531 gigabit Ethernet PHY
- onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
- Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
- Amlogic gxl MDIO mux
- WiFi:
- RealTek RTL8188EU (rtl8xxxu)
- Qualcomm Wi-Fi 7 devices (ath12k)
- CAN:
- Renesas R-Car V4H
Drivers
-------
- Bluetooth:
- Set Per Platform Antenna Gain (PPAG) for Intel controllers.
- Ethernet NICs:
- Intel (1G, igc):
- support TSN / Qbv / packet scheduling features of i226 model
- Intel (100G, ice):
- use GNSS subsystem instead of TTY
- multi-buffer XDP support
- extend support for GPIO pins to E823 devices
- nVidia/Mellanox:
- update the shared buffer configuration on PFC commands
- implement PTP adjphase function for HW offset control
- TC support for Geneve and GRE with VF tunnel offload
- more efficient crypto key management method
- multi-port eswitch support
- Netronome/Corigine:
- add DCB IEEE support
- support IPsec offloading for NFP3800
- Freescale/NXP (enetc):
- enetc: support XDP_REDIRECT for XDP non-linear buffers
- enetc: improve reconfig, avoid link flap and waiting for idle
- enetc: support MAC Merge layer
- Other NICs:
- sfc/ef100: add basic devlink support for ef100
- ionic: rx_push mode operation (writing descriptors via MMIO)
- bnxt: use the auxiliary bus abstraction for RDMA
- r8169: disable ASPM and reset bus in case of tx timeout
- cpsw: support QSGMII mode for J721e CPSW9G
- cpts: support pulse-per-second output
- ngbe: add an mdio bus driver
- usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
- r8152: handle devices with FW with NCM support
- amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
- virtio-net: support multi buffer XDP
- virtio/vsock: replace virtio_vsock_pkt with sk_buff
- tsnep: XDP support
- Ethernet high-speed switches:
- nVidia/Mellanox (mlxsw):
- add support for latency TLV (in FW control messages)
- Microchip (sparx5):
- separate explicit and implicit traffic forwarding rules, make
the implicit rules always active
- add support for egress DSCP rewrite
- IS0 VCAP support (Ingress Classification)
- IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS etc.)
- ES2 VCAP support (Egress Access Control)
- support for Per-Stream Filtering and Policing (802.1Q, 8.6.5.1)
- Ethernet embedded switches:
- Marvell (mv88e6xxx):
- add MAB (port auth) offload support
- enable PTP receive for mv88e6390
- NXP (ocelot):
- support MAC Merge layer
- support for the the vsc7512 internal copper phys
- Microchip:
- lan9303: convert to PHYLINK
- lan966x: support TC flower filter statistics
- lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
- lan937x: support Credit Based Shaper configuration
- ksz9477: support Energy Efficient Ethernet
- other:
- qca8k: convert to regmap read/write API, use bulk operations
- rswitch: Improve TX timestamp accuracy
- Intel WiFi (iwlwifi):
- EHT (Wi-Fi 7) rate reporting
- STEP equalizer support: transfer some STEP (connection to radio
on platforms with integrated wifi) related parameters from the
BIOS to the firmware.
- Qualcomm 802.11ax WiFi (ath11k):
- IPQ5018 support
- Fine Timing Measurement (FTM) responder role support
- channel 177 support
- MediaTek WiFi (mt76):
- per-PHY LED support
- mt7996: EHT (Wi-Fi 7) support
- Wireless Ethernet Dispatch (WED) reset support
- switch to using page pool allocator
- RealTek WiFi (rtw89):
- support new version of Bluetooth co-existance
- Mobile:
- rmnet: support TX aggregation.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
Pull networking updates from Jakub Kicinski:
"Core:
- Add dedicated kmem_cache for typical/small skb->head, avoid having
to access struct page at kfree time, and improve memory use.
- Introduce sysctl to set default RPS configuration for new netdevs.
- Define Netlink protocol specification format which can be used to
describe messages used by each family and auto-generate parsers.
Add tools for generating kernel data structures and uAPI headers.
- Expose all net/core sysctls inside netns.
- Remove 4s sleep in netpoll if carrier is instantly detected on
boot.
- Add configurable limit of MDB entries per port, and port-vlan.
- Continue populating drop reasons throughout the stack.
- Retire a handful of legacy Qdiscs and classifiers.
Protocols:
- Support IPv4 big TCP (TSO frames larger than 64kB).
- Add IP_LOCAL_PORT_RANGE socket option, to control local port range
on socket by socket basis.
- Track and report in procfs number of MPTCP sockets used.
- Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
manager.
- IPv6: don't check net.ipv6.route.max_size and rely on garbage
collection to free memory (similarly to IPv4).
- Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).
- ICMP: add per-rate limit counters.
- Add support for user scanning requests in ieee802154.
- Remove static WEP support.
- Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
reporting.
- WiFi 7 EHT channel puncturing support (client & AP).
BPF:
- Add a rbtree data structure following the "next-gen data structure"
precedent set by recently added linked list, that is, by using
kfunc + kptr instead of adding a new BPF map type.
- Expose XDP hints via kfuncs with initial support for RX hash and
timestamp metadata.
- Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
better support decap on GRE tunnel devices not operating in collect
metadata.
- Improve x86 JIT's codegen for PROBE_MEM runtime error checks.
- Remove the need for trace_printk_lock for bpf_trace_printk and
bpf_trace_vprintk helpers.
- Extend libbpf's bpf_tracing.h support for tracing arguments of
kprobes/uprobes and syscall as a special case.
- Significantly reduce the search time for module symbols by
livepatch and BPF.
- Enable cpumasks to be used as kptrs, which is useful for tracing
programs tracking which tasks end up running on which CPUs in
different time intervals.
- Add support for BPF trampoline on s390x and riscv64.
- Add capability to export the XDP features supported by the NIC.
- Add __bpf_kfunc tag for marking kernel functions as kfuncs.
- Add cgroup.memory=nobpf kernel parameter option to disable BPF
memory accounting for container environments.
Netfilter:
- Remove the CLUSTERIP target. It has been marked as obsolete for
years, and we still have WARN splats wrt races of the out-of-band
/proc interface installed by this target.
- Add 'destroy' commands to nf_tables. They are identical to the
existing 'delete' commands, but do not return an error if the
referenced object (set, chain, rule...) did not exist.
Driver API:
- Improve cpumask_local_spread() locality to help NICs set the right
IRQ affinity on AMD platforms.
- Separate C22 and C45 MDIO bus transactions more clearly.
- Introduce new DCB table to control DSCP rewrite on egress.
- Support configuration of Physical Layer Collision Avoidance (PLCA)
Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
shared medium Ethernet.
- Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
preemption of low priority frames by high priority frames.
- Add support for controlling MACSec offload using netlink SET.
- Rework devlink instance refcounts to allow registration and
de-registration under the instance lock. Split the code into
multiple files, drop some of the unnecessarily granular locks and
factor out common parts of netlink operation handling.
- Add TX frame aggregation parameters (for USB drivers).
- Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
messages with notifications for debug.
- Allow offloading of UDP NEW connections via act_ct.
- Add support for per action HW stats in TC.
- Support hardware miss to TC action (continue processing in SW from
a specific point in the action chain).
- Warn if old Wireless Extension user space interface is used with
modern cfg80211/mac80211 drivers. Do not support Wireless
Extensions for Wi-Fi 7 devices at all. Everyone should switch to
using nl80211 interface instead.
- Improve the CAN bit timing configuration. Use extack to return
error messages directly to user space, update the SJW handling,
including the definition of a new default value that will benefit
CAN-FD controllers, by increasing their oscillator tolerance.
New hardware / drivers:
- Ethernet:
- nVidia BlueField-3 support (control traffic driver)
- Ethernet support for imx93 SoCs
- Motorcomm yt8531 gigabit Ethernet PHY
- onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
- Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
- Amlogic gxl MDIO mux
- WiFi:
- RealTek RTL8188EU (rtl8xxxu)
- Qualcomm Wi-Fi 7 devices (ath12k)
- CAN:
- Renesas R-Car V4H
Drivers:
- Bluetooth:
- Set Per Platform Antenna Gain (PPAG) for Intel controllers.
- Ethernet NICs:
- Intel (1G, igc):
- support TSN / Qbv / packet scheduling features of i226 model
- Intel (100G, ice):
- use GNSS subsystem instead of TTY
- multi-buffer XDP support
- extend support for GPIO pins to E823 devices
- nVidia/Mellanox:
- update the shared buffer configuration on PFC commands
- implement PTP adjphase function for HW offset control
- TC support for Geneve and GRE with VF tunnel offload
- more efficient crypto key management method
- multi-port eswitch support
- Netronome/Corigine:
- add DCB IEEE support
- support IPsec offloading for NFP3800
- Freescale/NXP (enetc):
- support XDP_REDIRECT for XDP non-linear buffers
- improve reconfig, avoid link flap and waiting for idle
- support MAC Merge layer
- Other NICs:
- sfc/ef100: add basic devlink support for ef100
- ionic: rx_push mode operation (writing descriptors via MMIO)
- bnxt: use the auxiliary bus abstraction for RDMA
- r8169: disable ASPM and reset bus in case of tx timeout
- cpsw: support QSGMII mode for J721e CPSW9G
- cpts: support pulse-per-second output
- ngbe: add an mdio bus driver
- usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
- r8152: handle devices with FW with NCM support
- amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
- virtio-net: support multi buffer XDP
- virtio/vsock: replace virtio_vsock_pkt with sk_buff
- tsnep: XDP support
- Ethernet high-speed switches:
- nVidia/Mellanox (mlxsw):
- add support for latency TLV (in FW control messages)
- Microchip (sparx5):
- separate explicit and implicit traffic forwarding rules, make
the implicit rules always active
- add support for egress DSCP rewrite
- IS0 VCAP support (Ingress Classification)
- IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
etc.)
- ES2 VCAP support (Egress Access Control)
- support for Per-Stream Filtering and Policing (802.1Q,
8.6.5.1)
- Ethernet embedded switches:
- Marvell (mv88e6xxx):
- add MAB (port auth) offload support
- enable PTP receive for mv88e6390
- NXP (ocelot):
- support MAC Merge layer
- support for the the vsc7512 internal copper phys
- Microchip:
- lan9303: convert to PHYLINK
- lan966x: support TC flower filter statistics
- lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
- lan937x: support Credit Based Shaper configuration
- ksz9477: support Energy Efficient Ethernet
- other:
- qca8k: convert to regmap read/write API, use bulk operations
- rswitch: Improve TX timestamp accuracy
- Intel WiFi (iwlwifi):
- EHT (Wi-Fi 7) rate reporting
- STEP equalizer support: transfer some STEP (connection to radio
on platforms with integrated wifi) related parameters from the
BIOS to the firmware.
- Qualcomm 802.11ax WiFi (ath11k):
- IPQ5018 support
- Fine Timing Measurement (FTM) responder role support
- channel 177 support
- MediaTek WiFi (mt76):
- per-PHY LED support
- mt7996: EHT (Wi-Fi 7) support
- Wireless Ethernet Dispatch (WED) reset support
- switch to using page pool allocator
- RealTek WiFi (rtw89):
- support new version of Bluetooth co-existance
- Mobile:
- rmnet: support TX aggregation"
* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
page_pool: add a comment explaining the fragment counter usage
net: ethtool: fix __ethtool_dev_mm_supported() implementation
ethtool: pse-pd: Fix double word in comments
xsk: add linux/vmalloc.h to xsk.c
sefltests: netdevsim: wait for devlink instance after netns removal
selftest: fib_tests: Always cleanup before exit
net/mlx5e: Align IPsec ASO result memory to be as required by hardware
net/mlx5e: TC, Set CT miss to the specific ct action instance
net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
net/mlx5: Refactor tc miss handling to a single function
net/mlx5: Kconfig: Make tc offload depend on tc skb extension
net/sched: flower: Support hardware miss to tc action
net/sched: flower: Move filter handle initialization earlier
net/sched: cls_api: Support hardware miss to tc action
net/sched: Rename user cookie and act cookie
sfc: fix builds without CONFIG_RTC_LIB
sfc: clean up some inconsistent indentings
net/mlx4_en: Introduce flexible array to silence overflow warning
net: lan966x: Fix possible deadlock inside PTP
net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
...
The results of "access_ok()" can be mis-speculated. The result is that
you can end speculatively:
if (access_ok(from, size))
// Right here
even for bad from/size combinations. On first glance, it would be ideal
to just add a speculation barrier to "access_ok()" so that its results
can never be mis-speculated.
But there are lots of system calls just doing access_ok() via
"copy_to_user()" and friends (example: fstat() and friends). Those are
generally not problematic because they do not _consume_ data from
userspace other than the pointer. They are also very quick and common
system calls that should not be needlessly slowed down.
"copy_from_user()" on the other hand uses a user-controller pointer and
is frequently followed up with code that might affect caches. Take
something like this:
if (!copy_from_user(&kernelvar, uptr, size))
do_something_with(kernelvar);
If userspace passes in an evil 'uptr' that *actually* points to a kernel
addresses, and then do_something_with() has cache (or other)
side-effects, it could allow userspace to infer kernel data values.
Add a barrier to the common copy_from_user() code to prevent
mis-speculated values which happen after the copy.
Also add a stub for architectures that do not define barrier_nospec().
This makes the macro usable in generic code.
Since the barrier is now usable in generic code, the x86 #ifdef in the
BPF code can also go away.
Reported-by: Jordy Zomer <jordyzomer@google.com>
Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Daniel Borkmann <daniel@iogearbox.net> # BPF bits
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Merge tag 'fs.idmapped.v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping
Pull vfs idmapping updates from Christian Brauner:
- Last cycle we introduced the dedicated struct mnt_idmap type for
mount idmapping and the required infrastucture in 256c8aed2b ("fs:
introduce dedicated idmap type for mounts"). As promised in last
cycle's pull request message this converts everything to rely on
struct mnt_idmap.
Currently we still pass around the plain namespace that was attached
to a mount. This is in general pretty convenient but it makes it easy
to conflate namespaces that are relevant on the filesystem with
namespaces that are relevant on the mount level. Especially for
non-vfs developers without detailed knowledge in this area this was a
potential source for bugs.
This finishes the conversion. Instead of passing the plain namespace
around this updates all places that currently take a pointer to a
mnt_userns with a pointer to struct mnt_idmap.
Now that the conversion is done all helpers down to the really
low-level helpers only accept a struct mnt_idmap argument instead of
two namespace arguments.
Conflating mount and other idmappings will now cause the compiler to
complain loudly thus eliminating the possibility of any bugs. This
makes it impossible for filesystem developers to mix up mount and
filesystem idmappings as they are two distinct types and require
distinct helpers that cannot be used interchangeably.
Everything associated with struct mnt_idmap is moved into a single
separate file. With that change no code can poke around in struct
mnt_idmap. It can only be interacted with through dedicated helpers.
That means all filesystems are and all of the vfs is completely
oblivious to the actual implementation of idmappings.
We are now also able to extend struct mnt_idmap as we see fit. For
example, we can decouple it completely from namespaces for users that
don't require or don't want to use them at all. We can also extend
the concept of idmappings so we can cover filesystem specific
requirements.
In combination with the vfs{g,u}id_t work we finished in v6.2 this
makes this feature substantially more robust and thus difficult to
implement wrong by a given filesystem and also protects the vfs.
- Enable idmapped mounts for tmpfs and fulfill a longstanding request.
A long-standing request from users had been to make it possible to
create idmapped mounts for tmpfs. For example, to share the host's
tmpfs mount between multiple sandboxes. This is a prerequisite for
some advanced Kubernetes cases. Systemd also has a range of use-cases
to increase service isolation. And there are more users of this.
However, with all of the other work going on this was way down on the
priority list but luckily someone other than ourselves picked this
up.
As usual the patch is tiny as all the infrastructure work had been
done multiple kernel releases ago. In addition to all the tests that
we already have I requested that Rodrigo add a dedicated tmpfs
testsuite for idmapped mounts to xfstests. It is to be included into
xfstests during the v6.3 development cycle. This should add a slew of
additional tests.
* tag 'fs.idmapped.v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping: (26 commits)
shmem: support idmapped mounts for tmpfs
fs: move mnt_idmap
fs: port vfs{g,u}id helpers to mnt_idmap
fs: port fs{g,u}id helpers to mnt_idmap
fs: port i_{g,u}id_into_vfs{g,u}id() to mnt_idmap
fs: port i_{g,u}id_{needs_}update() to mnt_idmap
quota: port to mnt_idmap
fs: port privilege checking helpers to mnt_idmap
fs: port inode_owner_or_capable() to mnt_idmap
fs: port inode_init_owner() to mnt_idmap
fs: port acl to mnt_idmap
fs: port xattr to mnt_idmap
fs: port ->permission() to pass mnt_idmap
fs: port ->fileattr_set() to pass mnt_idmap
fs: port ->set_acl() to pass mnt_idmap
fs: port ->get_acl() to pass mnt_idmap
fs: port ->tmpfile() to pass mnt_idmap
fs: port ->rename() to pass mnt_idmap
fs: port ->mknod() to pass mnt_idmap
fs: port ->mkdir() to pass mnt_idmap
...
KPROBE program's user-facing context type is defined as typedef
bpf_user_pt_regs_t. This leads to a problem when trying to passing
kprobe/uprobe/usdt context argument into global subprog, as kernel
always strip away mods and typedefs of user-supplied type, but takes
expected type from bpf_ctx_convert as is, which causes mismatch.
Current way to work around this is to define a fake struct with the same
name as expected typedef:
struct bpf_user_pt_regs_t {};
__noinline my_global_subprog(struct bpf_user_pt_regs_t *ctx) { ... }
This patch fixes the issue by resolving expected type, if it's not
a struct. It still leaves the above work-around working for backwards
compatibility.
Fixes: 91cc1a9974 ("bpf: Annotate context types")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20230216045954.3002473-2-andrii@kernel.org
Currently the freed element in bpf memory allocator may be immediately
reused, for htab map the reuse will reinitialize special fields in map
value (e.g., bpf_spin_lock), but lookup procedure may still access
these special fields, and it may lead to hard-lockup as shown below:
NMI backtrace for cpu 16
CPU: 16 PID: 2574 Comm: htab.bin Tainted: G L 6.1.0+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
RIP: 0010:queued_spin_lock_slowpath+0x283/0x2c0
......
Call Trace:
<TASK>
copy_map_value_locked+0xb7/0x170
bpf_map_copy_value+0x113/0x3c0
__sys_bpf+0x1c67/0x2780
__x64_sys_bpf+0x1c/0x20
do_syscall_64+0x30/0x60
entry_SYSCALL_64_after_hwframe+0x46/0xb0
......
</TASK>
For htab map, just like the preallocated case, these is no need to
initialize these special fields in map value again once these fields
have been initialized. For preallocated htab map, these fields are
initialized through __GFP_ZERO in bpf_map_area_alloc(), so do the
similar thing for non-preallocated htab in bpf memory allocator. And
there is no need to use __GFP_ZERO for per-cpu bpf memory allocator,
because __alloc_percpu_gfp() does it implicitly.
Fixes: 0fd7c5d433 ("bpf: Optimize call_rcu in non-preallocated hash map.")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20230215082132.3856544-2-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
BPF_STX instruction preserves STACK_ZERO marks for variable offset
writes in situations like below:
*(u64*)(r10 - 8) = 0 ; STACK_ZERO marks for fp[-8]
r0 = random(-7, -1) ; some random number in range of [-7, -1]
r0 += r10 ; r0 is now a variable offset pointer to stack
r1 = 0
*(u8*)(r0) = r1 ; BPF_STX writing zero, STACK_ZERO mark for
; fp[-8] is preserved
This commit updates verifier.c:check_stack_write_var_off() to process
BPF_ST in a similar manner, e.g. the following example:
*(u64*)(r10 - 8) = 0 ; STACK_ZERO marks for fp[-8]
r0 = random(-7, -1) ; some random number in range of [-7, -1]
r0 += r10 ; r0 is now variable offset pointer to stack
*(u8*)(r0) = 0 ; BPF_ST writing zero, STACK_ZERO mark for
; fp[-8] is preserved
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230214232030.1502829-4-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
For aligned stack writes using BPF_ST instruction track stored values
in a same way BPF_STX is handled, e.g. make sure that the following
commands produce similar verifier knowledge:
fp[-8] = 42; r1 = 42;
fp[-8] = r1;
This covers two cases:
- non-null values written to stack are stored as spill of fake
registers;
- null values written to stack are stored as STACK_ZERO marks.
Previously both cases above used STACK_MISC marks instead.
Some verifier test cases relied on the old logic to obtain STACK_MISC
marks for some stack values. These test cases are updated in the same
commit to avoid failures during bisect.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230214232030.1502829-2-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Newly-added bpf_rbtree_{remove,first} kfuncs have some special properties
that require handling in the verifier:
* both bpf_rbtree_remove and bpf_rbtree_first return the type containing
the bpf_rb_node field, with the offset set to that field's offset,
instead of a struct bpf_rb_node *
* mark_reg_graph_node helper added in previous patch generalizes
this logic, use it
* bpf_rbtree_remove's node input is a node that's been inserted
in the tree - a non-owning reference.
* bpf_rbtree_remove must invalidate non-owning references in order to
avoid aliasing issue. Use previously-added
invalidate_non_owning_refs helper to mark this function as a
non-owning ref invalidation point.
* Unlike other functions, which convert one of their input arg regs to
non-owning reference, bpf_rbtree_first takes no arguments and just
returns a non-owning reference (possibly null)
* For now verifier logic for this is special-cased instead of
adding new kfunc flag.
This patch, along with the previous one, complete special verifier
handling for all rbtree API functions added in this series.
With functional verifier handling of rbtree_remove, under current
non-owning reference scheme, a node type with both bpf_{list,rb}_node
fields could cause the verifier to accept programs which remove such
nodes from collections they haven't been added to.
In order to prevent this, this patch adds a check to btf_parse_fields
which rejects structs with both bpf_{list,rb}_node fields. This is a
temporary measure that can be removed after "collection identity"
followup. See comment added in btf_parse_fields. A linked_list BTF test
exercising the new check is added in this patch as well.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230214004017.2534011-6-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Some BPF helpers take a callback function which the helper calls. For
each helper that takes such a callback, there's a special call to
__check_func_call with a callback-state-setting callback that sets up
verifier bpf_func_state for the callback's frame.
kfuncs don't have any of this infrastructure yet, so let's add it in
this patch, following existing helper pattern as much as possible. To
validate functionality of this added plumbing, this patch adds
callback handling for the bpf_rbtree_add kfunc and hopes to lay
groundwork for future graph datastructure callbacks.
In the "general plumbing" category we have:
* check_kfunc_call doing callback verification right before clearing
CALLER_SAVED_REGS, exactly like check_helper_call
* recognition of func_ptr BTF types in kfunc args as
KF_ARG_PTR_TO_CALLBACK + propagation of subprogno for this arg type
In the "rbtree_add / graph datastructure-specific plumbing" category:
* Since bpf_rbtree_add must be called while the spin_lock associated
with the tree is held, don't complain when callback's func_state
doesn't unlock it by frame exit
* Mark rbtree_add callback's args with ref_set_non_owning
to prevent rbtree api functions from being called in the callback.
Semantically this makes sense, as less() takes no ownership of its
args when determining which comes first.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230214004017.2534011-5-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Now that we find bpf_rb_root and bpf_rb_node in structs, let's give args
that contain those types special classification and properly handle
these types when checking kfunc args.
"Properly handling" these types largely requires generalizing similar
handling for bpf_list_{head,node}, with little new logic added in this
patch.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230214004017.2534011-4-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch adds implementations of bpf_rbtree_{add,remove,first}
and teaches verifier about their BTF_IDs as well as those of
bpf_rb_{root,node}.
All three kfuncs have some nonstandard component to their verification
that needs to be addressed in future patches before programs can
properly use them:
* bpf_rbtree_add: Takes 'less' callback, need to verify it
* bpf_rbtree_first: Returns ptr_to_node_type(off=rb_node_off) instead
of ptr_to_rb_node(off=0). Return value ref is
non-owning.
* bpf_rbtree_remove: Returns ptr_to_node_type(off=rb_node_off) instead
of ptr_to_rb_node(off=0). 2nd arg (node) is a
non-owning reference.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230214004017.2534011-3-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch adds special BPF_RB_{ROOT,NODE} btf_field_types similar to
BPF_LIST_{HEAD,NODE}, adds the necessary plumbing to detect the new
types, and adds bpf_rb_root_free function for freeing bpf_rb_root in
map_values.
structs bpf_rb_root and bpf_rb_node are opaque types meant to
obscure structs rb_root_cached rb_node, respectively.
btf_struct_access will prevent BPF programs from touching these special
fields automatically now that they're recognized.
btf_check_and_fixup_fields now groups list_head and rb_root together as
"graph root" fields and {list,rb}_node as "graph node", and does same
ownership cycle checking as before. Note that this function does _not_
prevent ownership type mixups (e.g. rb_root owning list_node) - that's
handled by btf_parse_graph_root.
After this patch, a bpf program can have a struct bpf_rb_root in a
map_value, but not add anything to nor do anything useful with it.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230214004017.2534011-2-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch introduces non-owning reference semantics to the verifier,
specifically linked_list API kfunc handling. release_on_unlock logic for
refs is refactored - with small functional changes - to implement these
semantics, and bpf_list_push_{front,back} are migrated to use them.
When a list node is pushed to a list, the program still has a pointer to
the node:
n = bpf_obj_new(typeof(*n));
bpf_spin_lock(&l);
bpf_list_push_back(&l, n);
/* n still points to the just-added node */
bpf_spin_unlock(&l);
What the verifier considers n to be after the push, and thus what can be
done with n, are changed by this patch.
Common properties both before/after this patch:
* After push, n is only a valid reference to the node until end of
critical section
* After push, n cannot be pushed to any list
* After push, the program can read the node's fields using n
Before:
* After push, n retains the ref_obj_id which it received on
bpf_obj_new, but the associated bpf_reference_state's
release_on_unlock field is set to true
* release_on_unlock field and associated logic is used to implement
"n is only a valid ref until end of critical section"
* After push, n cannot be written to, the node must be removed from
the list before writing to its fields
* After push, n is marked PTR_UNTRUSTED
After:
* After push, n's ref is released and ref_obj_id set to 0. NON_OWN_REF
type flag is added to reg's type, indicating that it's a non-owning
reference.
* NON_OWN_REF flag and logic is used to implement "n is only a
valid ref until end of critical section"
* n can be written to (except for special fields e.g. bpf_list_node,
timer, ...)
Summary of specific implementation changes to achieve the above:
* release_on_unlock field, ref_set_release_on_unlock helper, and logic
to "release on unlock" based on that field are removed
* The anonymous active_lock struct used by bpf_verifier_state is
pulled out into a named struct bpf_active_lock.
* NON_OWN_REF type flag is introduced along with verifier logic
changes to handle non-owning refs
* Helpers are added to use NON_OWN_REF flag to implement non-owning
ref semantics as described above
* invalidate_non_owning_refs - helper to clobber all non-owning refs
matching a particular bpf_active_lock identity. Replaces
release_on_unlock logic in process_spin_lock.
* ref_set_non_owning - set NON_OWN_REF type flag after doing some
sanity checking
* ref_convert_owning_non_owning - convert owning reference w/
specified ref_obj_id to non-owning references. Set NON_OWN_REF
flag for each reg with that ref_obj_id and 0-out its ref_obj_id
* Update linked_list selftests to account for minor semantic
differences introduced by this patch
* Writes to a release_on_unlock node ref are not allowed, while
writes to non-owning reference pointees are. As a result the
linked_list "write after push" failure tests are no longer scenarios
that should fail.
* The test##missing_lock##op and test##incorrect_lock##op
macro-generated failure tests need to have a valid node argument in
order to have the same error output as before. Otherwise
verification will fail early and the expected error output won't be seen.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230212092715.1422619-2-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
We can simply disable the bpf prog memory accouting by not setting the
GFP_ACCOUNT.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Link: https://lore.kernel.org/r/20230210154734.4416-5-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
We can simply set root memcg as the map's memcg to disable bpf memory
accounting. bpf_map_area_alloc is a little special as it gets the memcg
from current rather than from the map, so we need to disable GFP_ACCOUNT
specifically for it.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Link: https://lore.kernel.org/r/20230210154734.4416-4-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Introduce new helper bpf_map_kvcalloc() for the memory allocation in
bpf_local_storage(). Then the allocation will charge the memory from the
map instead of from current, though currently they are the same thing as
it is only used in map creation path now. By charging map's memory into
the memcg from the map, it will be more clear.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Link: https://lore.kernel.org/r/20230210154734.4416-3-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Daniel Borkmann says:
====================
pull-request: bpf-next 2023-02-11
We've added 96 non-merge commits during the last 14 day(s) which contain
a total of 152 files changed, 4884 insertions(+), 962 deletions(-).
There is a minor conflict in drivers/net/ethernet/intel/ice/ice_main.c
between commit 5b246e533d ("ice: split probe into smaller functions")
from the net-next tree and commit 66c0e13ad2 ("drivers: net: turn on
XDP features") from the bpf-next tree. Remove the hunk given ice_cfg_netdev()
is otherwise there a 2nd time, and add XDP features to the existing
ice_cfg_netdev() one:
[...]
ice_set_netdev_features(netdev);
netdev->xdp_features = NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT |
NETDEV_XDP_ACT_XSK_ZEROCOPY;
ice_set_ops(netdev);
[...]
Stephen's merge conflict mail:
https://lore.kernel.org/bpf/20230207101951.21a114fa@canb.auug.org.au/
The main changes are:
1) Add support for BPF trampoline on s390x which finally allows to remove many
test cases from the BPF CI's DENYLIST.s390x, from Ilya Leoshkevich.
2) Add multi-buffer XDP support to ice driver, from Maciej Fijalkowski.
3) Add capability to export the XDP features supported by the NIC.
Along with that, add a XDP compliance test tool,
from Lorenzo Bianconi & Marek Majtyka.
4) Add __bpf_kfunc tag for marking kernel functions as kfuncs,
from David Vernet.
5) Add a deep dive documentation about the verifier's register
liveness tracking algorithm, from Eduard Zingerman.
6) Fix and follow-up cleanups for resolve_btfids to be compiled
as a host program to avoid cross compile issues,
from Jiri Olsa & Ian Rogers.
7) Batch of fixes to the BPF selftest for xdp_hw_metadata which resulted
when testing on different NICs, from Jesper Dangaard Brouer.
8) Fix libbpf to better detect kernel version code on Debian, from Hao Xiang.
9) Extend libbpf to add an option for when the perf buffer should
wake up, from Jon Doron.
10) Follow-up fix on xdp_metadata selftest to just consume on TX
completion, from Stanislav Fomichev.
11) Extend the kfuncs.rst document with description on kfunc
lifecycle & stability expectations, from David Vernet.
12) Fix bpftool prog profile to skip attaching to offline CPUs,
from Tonghao Zhang.
====================
Link: https://lore.kernel.org/r/20230211002037.8489-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
skbuff_head_cache is misnamed (perhaps for historical reasons?)
because it does not hold heads. Head is the buffer which skb->data
points to, and also where shinfo lives. struct sk_buff is a metadata
structure, not the head.
Eric recently added skb_small_head_cache (which allocates actual
head buffers), let that serve as an excuse to finally clean this up :)
Leave the user-space visible name intact, it could possibly be uAPI.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Replace direct modifications to vma->vm_flags with calls to modifier
functions to be able to track flag changes and to keep vma locking
correctness.
[akpm@linux-foundation.org: fix drivers/misc/open-dice.c, per Hyeonggon Yoo]
Link: https://lkml.kernel.org/r/20230126193752.297968-5-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjun Roy <arjunroy@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Minchan Kim <minchan@google.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Peter Oskolkov <posk@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Punit Agrawal <punit.agrawal@bytedance.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The do_idr_lock parameter to bpf_map_free_id was introduced by commit
bd5f5f4ecb ("bpf: Add BPF_MAP_GET_FD_BY_ID"). However, all callers set
do_idr_lock = true since commit 1e0bd5a091 ("bpf: Switch bpf_map ref
counter to atomic64_t so bpf_map_inc() never fails").
While at it also inline __bpf_map_put into its only caller bpf_map_put
now that do_idr_lock can be dropped from its signature.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Link: https://lore.kernel.org/r/20230202141921.4424-1-tklauser@distanz.ch
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Now that we have the __bpf_kfunc tag, we should use add it to all
existing kfuncs to ensure that they'll never be elided in LTO builds.
Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20230201173016.342758-4-void@manifault.com
s390x eBPF JIT needs to know whether a function return value is signed
and which function arguments are signed, in order to generate code
compliant with the s390x ABI.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/20230128000650.1516334-26-iii@linux.ibm.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
iterators.lskel.h is little-endian, therefore bpf iterator is currently
broken on big-endian systems. Introduce a big-endian version and add
instructions regarding its generation. Unfortunately bpftool's
cross-endianness capabilities are limited to BTF right now, so the
procedure requires access to a big-endian machine or a configured
emulator.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/20230128000650.1516334-25-iii@linux.ibm.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The first element of a struct bpf_cpumask is a cpumask_t. This is done
to allow struct bpf_cpumask to be cast to a struct cpumask. If this
element were ever moved to another field, any BPF program passing a
struct bpf_cpumask * to a kfunc expecting a const struct cpumask * would
immediately fail to load. Add a build-time assertion so this is
assumption is captured and verified.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230128141537.100777-1-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:
====================
bpf-next 2023-01-28
We've added 124 non-merge commits during the last 22 day(s) which contain
a total of 124 files changed, 6386 insertions(+), 1827 deletions(-).
The main changes are:
1) Implement XDP hints via kfuncs with initial support for RX hash and
timestamp metadata kfuncs, from Stanislav Fomichev and
Toke Høiland-Jørgensen.
Measurements on overhead: https://lore.kernel.org/bpf/875yellcx6.fsf@toke.dk
2) Extend libbpf's bpf_tracing.h support for tracing arguments of
kprobes/uprobes and syscall as a special case, from Andrii Nakryiko.
3) Significantly reduce the search time for module symbols by livepatch
and BPF, from Jiri Olsa and Zhen Lei.
4) Enable cpumasks to be used as kptrs, which is useful for tracing
programs tracking which tasks end up running on which CPUs
in different time intervals, from David Vernet.
5) Fix several issues in the dynptr processing such as stack slot liveness
propagation, missing checks for PTR_TO_STACK variable offset, etc,
from Kumar Kartikeya Dwivedi.
6) Various performance improvements, fixes, and introduction of more
than just one XDP program to XSK selftests, from Magnus Karlsson.
7) Big batch to BPF samples to reduce deprecated functionality,
from Daniel T. Lee.
8) Enable struct_ops programs to be sleepable in verifier,
from David Vernet.
9) Reduce pr_warn() noise on BTF mismatches when they are expected under
the CONFIG_MODULE_ALLOW_BTF_MISMATCH config anyway, from Connor O'Brien.
10) Describe modulo and division by zero behavior of the BPF runtime
in BPF's instruction specification document, from Dave Thaler.
11) Several improvements to libbpf API documentation in libbpf.h,
from Grant Seltzer.
12) Improve resolve_btfids header dependencies related to subcmd and add
proper support for HOSTCC, from Ian Rogers.
13) Add ipip6 and ip6ip decapsulation support for bpf_skb_adjust_room()
helper along with BPF selftests, from Ziyang Xuan.
14) Simplify the parsing logic of structure parameters for BPF trampoline
in the x86-64 JIT compiler, from Pu Lehui.
15) Get BTF working for kernels with CONFIG_RUST enabled by excluding
Rust compilation units with pahole, from Martin Rodriguez Reboredo.
16) Get bpf_setsockopt() working for kTLS on top of TCP sockets,
from Kui-Feng Lee.
17) Disable stack protection for BPF objects in bpftool given BPF backends
don't support it, from Holger Hoffstätte.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (124 commits)
selftest/bpf: Make crashes more debuggable in test_progs
libbpf: Add documentation to map pinning API functions
libbpf: Fix malformed documentation formatting
selftests/bpf: Properly enable hwtstamp in xdp_hw_metadata
selftests/bpf: Calls bpf_setsockopt() on a ktls enabled socket.
bpf: Check the protocol of a sock to agree the calls to bpf_setsockopt().
bpf/selftests: Verify struct_ops prog sleepable behavior
bpf: Pass const struct bpf_prog * to .check_member
libbpf: Support sleepable struct_ops.s section
bpf: Allow BPF_PROG_TYPE_STRUCT_OPS programs to be sleepable
selftests/bpf: Fix vmtest static compilation error
tools/resolve_btfids: Alter how HOSTCC is forced
tools/resolve_btfids: Install subcmd headers
bpf/docs: Document the nocast aliasing behavior of ___init
bpf/docs: Document how nested trusted fields may be defined
bpf/docs: Document cpumask kfuncs in a new file
selftests/bpf: Add selftest suite for cpumask kfuncs
selftests/bpf: Add nested trust selftests suite
bpf: Enable cpumasks to be queried and used as kptrs
bpf: Disallow NULLable pointers for trusted kfuncs
...
====================
Link: https://lore.kernel.org/r/20230128004827.21371-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The kernel crash was caused by a BPF program attached to the
"lsm_cgroup/socket_sock_rcv_skb" hook, which performed a call to
`bpf_setsockopt()` in order to set the TCP_NODELAY flag as an
example. Flags like TCP_NODELAY can prompt the kernel to flush a
socket's outgoing queue, and this hook
"lsm_cgroup/socket_sock_rcv_skb" is frequently triggered by
softirqs. The issue was that in certain circumstances, when
`tcp_write_xmit()` was called to flush the queue, it would also allow
BH (bottom-half) to run. This could lead to our program attempting to
flush the same socket recursively, which caused a `skbuff` to be
unlinked twice.
`security_sock_rcv_skb()` is triggered by `tcp_filter()`. This occurs
before the sock ownership is checked in `tcp_v4_rcv()`. Consequently,
if a bpf program runs on `security_sock_rcv_skb()` while under softirq
conditions, it may not possess the lock needed for `bpf_setsockopt()`,
thus presenting an issue.
The patch fixes this issue by ensuring that a BPF program attached to
the "lsm_cgroup/socket_sock_rcv_skb" hook is not allowed to call
`bpf_setsockopt()`.
The differences from v1 are
- changing commit log to explain holding the lock of the sock,
- emphasizing that TCP_NODELAY is not the only flag, and
- adding the fixes tag.
v1: https://lore.kernel.org/bpf/20230125000244.1109228-1-kuifeng@meta.com/
Signed-off-by: Kui-Feng Lee <kuifeng@meta.com>
Fixes: 9113d7e48e ("bpf: expose bpf_{g,s}etsockopt to lsm cgroup")
Link: https://lore.kernel.org/r/20230127001732.4162630-1-kuifeng@meta.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
The .check_member field of struct bpf_struct_ops is currently passed the
member's btf_type via const struct btf_type *t, and a const struct
btf_member *member. This allows the struct_ops implementation to check
whether e.g. an ops is supported, but it would be useful to also enforce
that the struct_ops prog being loaded for that member has other
qualities, like being sleepable (or not). This patch therefore updates
the .check_member() callback to also take a const struct bpf_prog *prog
argument.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230125164735.785732-4-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
BPF struct_ops programs currently cannot be marked as sleepable. This
need not be the case -- struct_ops programs can be sleepable, and e.g.
invoke kfuncs that export the KF_SLEEPABLE flag. So as to allow future
struct_ops programs to invoke such kfuncs, this patch updates the
verifier to allow struct_ops programs to be sleepable. A follow-on patch
will add support to libbpf for specifying struct_ops.s as a sleepable
struct_ops program, and then another patch will add testcases to the
dummy_st_ops selftest suite which test sleepable struct_ops behavior.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230125164735.785732-2-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Now that we've added a series of new cpumask kfuncs, we should document
them so users can easily use them. This patch adds a new cpumasks.rst
file to document them.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230125143816.721952-6-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Certain programs may wish to be able to query cpumasks. For example, if
a program that is tracing percpu operations wishes to track which tasks
end up running on which CPUs, it could be useful to associate that with
the tasks' cpumasks. Similarly, programs tracking NUMA allocations, CPU
scheduling domains, etc, could potentially benefit from being able to
see which CPUs a task could be migrated to.
This patch enables these types of use cases by introducing a series of
bpf_cpumask_* kfuncs. Amongst these kfuncs, there are two separate
"classes" of operations:
1. kfuncs which allow the caller to allocate and mutate their own
cpumask kptrs in the form of a struct bpf_cpumask * object. Such
kfuncs include e.g. bpf_cpumask_create() to allocate the cpumask, and
bpf_cpumask_or() to mutate it. "Regular" cpumasks such as p->cpus_ptr
may not be passed to these kfuncs, and the verifier will ensure this
is the case by comparing BTF IDs.
2. Read-only operations which operate on const struct cpumask *
arguments. For example, bpf_cpumask_test_cpu(), which tests whether a
CPU is set in the cpumask. Any trusted struct cpumask * or struct
bpf_cpumask * may be passed to these kfuncs. The verifier allows
struct bpf_cpumask * even though the kfunc is defined with struct
cpumask * because the first element of a struct bpf_cpumask is a
cpumask_t, so it is safe to cast.
A follow-on patch will add selftests which validate these kfuncs, and
another will document them.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230125143816.721952-3-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
KF_TRUSTED_ARGS kfuncs currently have a subtle and insidious bug in
validating pointers to scalars. Say that you have a kfunc like the
following, which takes an array as the first argument:
bool bpf_cpumask_empty(const struct cpumask *cpumask)
{
return cpumask_empty(cpumask);
}
...
BTF_ID_FLAGS(func, bpf_cpumask_empty, KF_TRUSTED_ARGS)
...
If a BPF program were to invoke the kfunc with a NULL argument, it would
crash the kernel. The reason is that struct cpumask is defined as a
bitmap, which is itself defined as an array, and is accessed as a memory
address by bitmap operations. So when the verifier analyzes the
register, it interprets it as a pointer to a scalar struct, which is an
array of size 8. check_mem_reg() then sees that the register is NULL and
returns 0, and the kfunc crashes when it passes it down to the cpumask
wrappers.
To fix this, this patch adds a check for KF_ARG_PTR_TO_MEM which
verifies that the register doesn't contain a possibly-NULL pointer if
the kfunc is KF_TRUSTED_ARGS.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230125143816.721952-2-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When validating BTF types for KF_TRUSTED_ARGS kfuncs, the verifier
currently enforces that the top-level type must match when calling
the kfunc. In other words, the verifier does not allow the BPF program
to pass a bitwise equivalent struct, despite it being allowed according
to the C standard.
For example, if you have the following type:
struct nf_conn___init {
struct nf_conn ct;
};
The C standard stipulates that it would be safe to pass a struct
nf_conn___init to a kfunc expecting a struct nf_conn. The verifier
currently disallows this, however, as semantically kfuncs may want to
enforce that structs that have equivalent types according to the C
standard, but have different BTF IDs, are not able to be passed to
kfuncs expecting one or the other. For example, struct nf_conn___init
may not be queried / looked up, as it is allocated but may not yet be
fully initialized.
On the other hand, being able to pass types that are equivalent
according to the C standard will be useful for other types of kfunc /
kptrs enabled by BPF. For example, in a follow-on patch, a series of
kfuncs will be added which allow programs to do bitwise queries on
cpumasks that are either allocated by the program (in which case they'll
be a 'struct bpf_cpumask' type that wraps a cpumask_t as its first
element), or a cpumask that was allocated by the main kernel (in which
case it will just be a straight cpumask_t, as in task->cpus_ptr).
Having the two types of cpumasks allows us to distinguish between the
two for when a cpumask is read-only vs. mutatable. A struct bpf_cpumask
can be mutated by e.g. bpf_cpumask_clear(), whereas a regular cpumask_t
cannot be. On the other hand, a struct bpf_cpumask can of course be
queried in the exact same manner as a cpumask_t, with e.g.
bpf_cpumask_test_cpu().
If we were to enforce that top level types match, then a user that's
passing a struct bpf_cpumask to a read-only cpumask_t argument would
have to cast with something like bpf_cast_to_kern_ctx() (which itself
would need to be updated to expect the alias, and currently it only
accommodates a single alias per prog type). Additionally, not specifying
KF_TRUSTED_ARGS is not an option, as some kfuncs take one argument as a
struct bpf_cpumask *, and another as a struct cpumask *
(i.e. cpumask_t).
In order to enable this, this patch relaxes the constraint that a
KF_TRUSTED_ARGS kfunc must have strict type matching, and instead only
enforces strict type matching if a type is observed to be a "no-cast
alias" (i.e., that the type names are equivalent, but one is suffixed
with ___init).
Additionally, in order to try and be conservative and match existing
behavior / expectations, this patch also enforces strict type checking
for acquire kfuncs. We were already enforcing it for release kfuncs, so
this should also improve the consistency of the semantics for kfuncs.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230120192523.3650503-3-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In kfuncs, a "trusted" pointer is a pointer that the kfunc can assume is
safe, and which the verifier will allow to be passed to a
KF_TRUSTED_ARGS kfunc. Currently, a KF_TRUSTED_ARGS kfunc disallows any
pointer to be passed at a nonzero offset, but sometimes this is in fact
safe if the "nested" pointer's lifetime is inherited from its parent.
For example, the const cpumask_t *cpus_ptr field in a struct task_struct
will remain valid until the task itself is destroyed, and thus would
also be safe to pass to a KF_TRUSTED_ARGS kfunc.
While it would be conceptually simple to enable this by using BTF tags,
gcc unfortunately does not yet support this. In the interim, this patch
enables support for this by using a type-naming convention. A new
BTF_TYPE_SAFE_NESTED macro is defined in verifier.c which allows a
developer to specify the nested fields of a type which are considered
trusted if its parent is also trusted. The verifier is also updated to
account for this. A patch with selftests will be added in a follow-on
change, along with documentation for this feature.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230120192523.3650503-2-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Instead of rejecting the attaching of PROG_TYPE_EXT programs to XDP
programs that consume HW metadata, implement support for propagating the
offload information. The extension program doesn't need to set a flag or
ifindex, these will just be propagated from the target by the verifier.
We need to create a separate offload object for the extension program,
though, since it can be reattached to a different program later (which
means we can't just inherit the offload information from the target).
An additional check is added on attach that the new target is compatible
with the offload information in the extension prog.
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230119221536.3349901-9-sdf@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Define a new kfunc set (xdp_metadata_kfunc_ids) which implements all possible
XDP metatada kfuncs. Not all devices have to implement them. If kfunc is not
supported by the target device, the default implementation is called instead.
The verifier, at load time, replaces a call to the generic kfunc with a call
to the per-device one. Per-device kfunc pointers are stored in separate
struct xdp_metadata_ops.
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Anatoly Burakov <anatoly.burakov@intel.com>
Cc: Alexander Lobakin <alexandr.lobakin@intel.com>
Cc: Magnus Karlsson <magnus.karlsson@gmail.com>
Cc: Maryam Tahhan <mtahhan@redhat.com>
Cc: xdp-hints@xdp-project.net
Cc: netdev@vger.kernel.org
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230119221536.3349901-8-sdf@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
New flag BPF_F_XDP_DEV_BOUND_ONLY plus all the infra to have a way
to associate a netdev with a BPF program at load time.
netdevsim checks are dropped in favor of generic check in dev_xdp_attach.
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Anatoly Burakov <anatoly.burakov@intel.com>
Cc: Alexander Lobakin <alexandr.lobakin@intel.com>
Cc: Magnus Karlsson <magnus.karlsson@gmail.com>
Cc: Maryam Tahhan <mtahhan@redhat.com>
Cc: xdp-hints@xdp-project.net
Cc: netdev@vger.kernel.org
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230119221536.3349901-6-sdf@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
To avoid adding forward declarations in the main patch, shuffle
some code around. No functional changes.
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Anatoly Burakov <anatoly.burakov@intel.com>
Cc: Alexander Lobakin <alexandr.lobakin@intel.com>
Cc: Magnus Karlsson <magnus.karlsson@gmail.com>
Cc: Maryam Tahhan <mtahhan@redhat.com>
Cc: xdp-hints@xdp-project.net
Cc: netdev@vger.kernel.org
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230119221536.3349901-5-sdf@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
So we don't have to initialize it manually from several paths.
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Anatoly Burakov <anatoly.burakov@intel.com>
Cc: Alexander Lobakin <alexandr.lobakin@intel.com>
Cc: Magnus Karlsson <magnus.karlsson@gmail.com>
Cc: Maryam Tahhan <mtahhan@redhat.com>
Cc: xdp-hints@xdp-project.net
Cc: netdev@vger.kernel.org
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230119221536.3349901-4-sdf@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
BPF offloading infra will be reused to implement
bound-but-not-offloaded bpf programs. Rename existing
helpers for clarity. No functional changes.
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Anatoly Burakov <anatoly.burakov@intel.com>
Cc: Alexander Lobakin <alexandr.lobakin@intel.com>
Cc: Magnus Karlsson <magnus.karlsson@gmail.com>
Cc: Maryam Tahhan <mtahhan@redhat.com>
Cc: xdp-hints@xdp-project.net
Cc: netdev@vger.kernel.org
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230119221536.3349901-3-sdf@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Currently, process_dynptr_func first calls dynptr_get_spi and then
is_dynptr_reg_valid_init and is_dynptr_reg_valid_uninit have to call it
again to obtain the spi value. Instead of doing this twice, reuse the
already obtained value (which is by default 0, and is only set for
PTR_TO_STACK, and only used in that case in aforementioned functions).
The input value for these two functions will either be -ERANGE or >= 1,
and can either be permitted or rejected based on the respective check.
Suggested-by: Joanne Koong <joannelkoong@gmail.com>
Acked-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230121002241.2113993-8-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently, a check on spi resides in dynptr_get_spi, while others
checking its validity for being within the allocated stack slots happens
in is_spi_bounds_valid. Almost always barring a couple of cases (where
being beyond allocated stack slots is not an error as stack slots need
to be populated), both are used together to make checks. Hence, subsume
the is_spi_bounds_valid check in dynptr_get_spi, and return -ERANGE to
specially distinguish the case where spi is valid but not within
allocated slots in the stack state.
The is_spi_bounds_valid function is still kept around as it is a generic
helper that will be useful for other objects on stack similar to dynptr
in the future.
Suggested-by: Joanne Koong <joannelkoong@gmail.com>
Acked-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230121002241.2113993-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Consider a program like below:
void prog(void)
{
{
struct bpf_dynptr ptr;
bpf_dynptr_from_mem(...);
}
...
{
struct bpf_dynptr ptr;
bpf_dynptr_from_mem(...);
}
}
Here, the C compiler based on lifetime rules in the C standard would be
well within in its rights to share stack storage for dynptr 'ptr' as
their lifetimes do not overlap in the two distinct scopes. Currently,
such an example would be rejected by the verifier, but this is too
strict. Instead, we should allow reinitializing over dynptr stack slots
and forget information about the old dynptr object.
The destroy_if_dynptr_stack_slot function already makes necessary checks
to avoid overwriting referenced dynptr slots. This is done to present a
better error message instead of forgetting dynptr information on stack
and preserving reference state, leading to an inevitable but
undecipherable error at the end about an unreleased reference which has
to be associated back to its allocating call instruction to make any
sense to the user.
Acked-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230121002241.2113993-6-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The previous commit implemented destroy_if_dynptr_stack_slot. It
destroys the dynptr which given spi belongs to, but still doesn't
invalidate the slices that belong to such a dynptr. While for the case
of referenced dynptr, we don't allow their overwrite and return an error
early, we still allow it and destroy the dynptr for unreferenced dynptr.
To be able to enable precise and scoped invalidation of dynptr slices in
this case, we must be able to associate the source dynptr of slices that
have been obtained using bpf_dynptr_data. When doing destruction, only
slices belonging to the dynptr being destructed should be invalidated,
and nothing else. Currently, dynptr slices belonging to different
dynptrs are indistinguishible.
Hence, allocate a unique id to each dynptr (CONST_PTR_TO_DYNPTR and
those on stack). This will be stored as part of reg->id. Whenever using
bpf_dynptr_data, transfer this unique dynptr id to the returned
PTR_TO_MEM_OR_NULL slice pointer, and store it in a new per-PTR_TO_MEM
dynptr_id register state member.
Finally, after establishing such a relationship between dynptrs and
their slices, implement precise invalidation logic that only invalidates
slices belong to the destroyed dynptr in destroy_if_dynptr_stack_slot.
Acked-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230121002241.2113993-5-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently, while reads are disallowed for dynptr stack slots, writes are
not. Reads don't work from both direct access and helpers, while writes
do work in both cases, but have the effect of overwriting the slot_type.
While this is fine, handling for a few edge cases is missing. Firstly,
a user can overwrite the stack slots of dynptr partially.
Consider the following layout:
spi: [d][d][?]
2 1 0
First slot is at spi 2, second at spi 1.
Now, do a write of 1 to 8 bytes for spi 1.
This will essentially either write STACK_MISC for all slot_types or
STACK_MISC and STACK_ZERO (in case of size < BPF_REG_SIZE partial write
of zeroes). The end result is that slot is scrubbed.
Now, the layout is:
spi: [d][m][?]
2 1 0
Suppose if user initializes spi = 1 as dynptr.
We get:
spi: [d][d][d]
2 1 0
But this time, both spi 2 and spi 1 have first_slot = true.
Now, when passing spi 2 to dynptr helper, it will consider it as
initialized as it does not check whether second slot has first_slot ==
false. And spi 1 should already work as normal.
This effectively replaced size + offset of first dynptr, hence allowing
invalid OOB reads and writes.
Make a few changes to protect against this:
When writing to PTR_TO_STACK using BPF insns, when we touch spi of a
STACK_DYNPTR type, mark both first and second slot (regardless of which
slot we touch) as STACK_INVALID. Reads are already prevented.
Second, prevent writing to stack memory from helpers if the range may
contain any STACK_DYNPTR slots. Reads are already prevented.
For helpers, we cannot allow it to destroy dynptrs from the writes as
depending on arguments, helper may take uninit_mem and dynptr both at
the same time. This would mean that helper may write to uninit_mem
before it reads the dynptr, which would be bad.
PTR_TO_MEM: [?????dd]
Depending on the code inside the helper, it may end up overwriting the
dynptr contents first and then read those as the dynptr argument.
Verifier would only simulate destruction when it does byte by byte
access simulation in check_helper_call for meta.access_size, and
fail to catch this case, as it happens after argument checks.
The same would need to be done for any other non-trivial objects created
on the stack in the future, such as bpf_list_head on stack, or
bpf_rb_root on stack.
A common misunderstanding in the current code is that MEM_UNINIT means
writes, but note that writes may also be performed even without
MEM_UNINIT in case of helpers, in that case the code after handling meta
&& meta->raw_mode will complain when it sees STACK_DYNPTR. So that
invalid read case also covers writes to potential STACK_DYNPTR slots.
The only loophole was in case of meta->raw_mode which simulated writes
through instructions which could overwrite them.
A future series sequenced after this will focus on the clean up of
helper access checks and bugs around that.
Fixes: 97e03f5210 ("bpf: Add verifier support for dynptrs")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230121002241.2113993-4-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently, the dynptr function is not checking the variable offset part
of PTR_TO_STACK that it needs to check. The fixed offset is considered
when computing the stack pointer index, but if the variable offset was
not a constant (such that it could not be accumulated in reg->off), we
will end up a discrepency where runtime pointer does not point to the
actual stack slot we mark as STACK_DYNPTR.
It is impossible to precisely track dynptr state when variable offset is
not constant, hence, just like bpf_timer, kptr, bpf_spin_lock, etc.
simply reject the case where reg->var_off is not constant. Then,
consider both reg->off and reg->var_off.value when computing the stack
pointer index.
A new helper dynptr_get_spi is introduced to hide over these details
since the dynptr needs to be located in multiple places outside the
process_dynptr_func checks, hence once we know it's a PTR_TO_STACK, we
need to enforce these checks in all places.
Note that it is disallowed for unprivileged users to have a non-constant
var_off, so this problem should only be possible to trigger from
programs having CAP_PERFMON. However, its effects can vary.
Without the fix, it is possible to replace the contents of the dynptr
arbitrarily by making verifier mark different stack slots than actual
location and then doing writes to the actual stack address of dynptr at
runtime.
Fixes: 97e03f5210 ("bpf: Add verifier support for dynptrs")
Acked-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230121002241.2113993-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The root of the problem is missing liveness marking for STACK_DYNPTR
slots. This leads to all kinds of problems inside stacksafe.
The verifier by default inside stacksafe ignores spilled_ptr in stack
slots which do not have REG_LIVE_READ marks. Since this is being checked
in the 'old' explored state, it must have already done clean_live_states
for this old bpf_func_state. Hence, it won't be receiving any more
liveness marks from to be explored insns (it has received REG_LIVE_DONE
marking from liveness point of view).
What this means is that verifier considers that it's safe to not compare
the stack slot if was never read by children states. While liveness
marks are usually propagated correctly following the parentage chain for
spilled registers (SCALAR_VALUE and PTR_* types), the same is not the
case for STACK_DYNPTR.
clean_live_states hence simply rewrites these stack slots to the type
STACK_INVALID since it sees no REG_LIVE_READ marks.
The end result is that we will never see STACK_DYNPTR slots in explored
state. Even if verifier was conservatively matching !REG_LIVE_READ
slots, very next check continuing the stacksafe loop on seeing
STACK_INVALID would again prevent further checks.
Now as long as verifier stores an explored state which we can compare to
when reaching a pruning point, we can abuse this bug to make verifier
prune search for obviously unsafe paths using STACK_DYNPTR slots
thinking they are never used hence safe.
Doing this in unprivileged mode is a bit challenging. add_new_state is
only set when seeing BPF_F_TEST_STATE_FREQ (which requires privileges)
or when jmps_processed difference is >= 2 and insn_processed difference
is >= 8. So coming up with the unprivileged case requires a little more
work, but it is still totally possible. The test case being discussed
below triggers the heuristic even in unprivileged mode.
However, it no longer works since commit
8addbfc7b3 ("bpf: Gate dynptr API behind CAP_BPF").
Let's try to study the test step by step.
Consider the following program (C style BPF ASM):
0 r0 = 0;
1 r6 = &ringbuf_map;
3 r1 = r6;
4 r2 = 8;
5 r3 = 0;
6 r4 = r10;
7 r4 -= -16;
8 call bpf_ringbuf_reserve_dynptr;
9 if r0 == 0 goto pc+1;
10 goto pc+1;
11 *(r10 - 16) = 0xeB9F;
12 r1 = r10;
13 r1 -= -16;
14 r2 = 0;
15 call bpf_ringbuf_discard_dynptr;
16 r0 = 0;
17 exit;
We know that insn 12 will be a pruning point, hence if we force
add_new_state for it, it will first verify the following path as
safe in straight line exploration:
0 1 3 4 5 6 7 8 9 -> 10 -> (12) 13 14 15 16 17
Then, when we arrive at insn 12 from the following path:
0 1 3 4 5 6 7 8 9 -> 11 (12)
We will find a state that has been verified as safe already at insn 12.
Since register state is same at this point, regsafe will pass. Next, in
stacksafe, for spi = 0 and spi = 1 (location of our dynptr) is skipped
seeing !REG_LIVE_READ. The rest matches, so stacksafe returns true.
Next, refsafe is also true as reference state is unchanged in both
states.
The states are considered equivalent and search is pruned.
Hence, we are able to construct a dynptr with arbitrary contents and use
the dynptr API to operate on this arbitrary pointer and arbitrary size +
offset.
To fix this, first define a mark_dynptr_read function that propagates
liveness marks whenever a valid initialized dynptr is accessed by dynptr
helpers. REG_LIVE_WRITTEN is marked whenever we initialize an
uninitialized dynptr. This is done in mark_stack_slots_dynptr. It allows
screening off mark_reg_read and not propagating marks upwards from that
point.
This ensures that we either set REG_LIVE_READ64 on both dynptr slots, or
none, so clean_live_states either sets both slots to STACK_INVALID or
none of them. This is the invariant the checks inside stacksafe rely on.
Next, do a complete comparison of both stack slots whenever they have
STACK_DYNPTR. Compare the dynptr type stored in the spilled_ptr, and
also whether both form the same first_slot. Only then is the later path
safe.
Fixes: 97e03f5210 ("bpf: Add verifier support for dynptrs")
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230121002241.2113993-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
We take the BTF reference before we register dtors and we need
to put it back when it's done.
We probably won't se a problem with kernel BTF, but module BTF
would stay loaded (because of the extra ref) even when its module
is removed.
Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Fixes: 5ce937d613 ("bpf: Populate pairs of btf_id and destructor kfunc in btf")
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230120122148.1522359-1-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Register range information is copied in several places. The intent is
to transfer range/id information from one register/stack spill to
another. Currently this is done using direct register assignment, e.g.:
static void find_equal_scalars(..., struct bpf_reg_state *known_reg)
{
...
struct bpf_reg_state *reg;
...
*reg = *known_reg;
...
}
However, such assignments also copy the following bpf_reg_state fields:
struct bpf_reg_state {
...
struct bpf_reg_state *parent;
...
enum bpf_reg_liveness live;
...
};
Copying of these fields is accidental and incorrect, as could be
demonstrated by the following example:
0: call ktime_get_ns()
1: r6 = r0
2: call ktime_get_ns()
3: r7 = r0
4: if r0 > r6 goto +1 ; r0 & r6 are unbound thus generated
; branch states are identical
5: *(u64 *)(r10 - 8) = 0xdeadbeef ; 64-bit write to fp[-8]
--- checkpoint ---
6: r1 = 42 ; r1 marked as written
7: *(u8 *)(r10 - 8) = r1 ; 8-bit write, fp[-8] parent & live
; overwritten
8: r2 = *(u64 *)(r10 - 8)
9: r0 = 0
10: exit
This example is unsafe because 64-bit write to fp[-8] at (5) is
conditional, thus not all bytes of fp[-8] are guaranteed to be set
when it is read at (8). However, currently the example passes
verification.
First, the execution path 1-10 is examined by verifier.
Suppose that a new checkpoint is created by is_state_visited() at (6).
After checkpoint creation:
- r1.parent points to checkpoint.r1,
- fp[-8].parent points to checkpoint.fp[-8].
At (6) the r1.live is set to REG_LIVE_WRITTEN.
At (7) the fp[-8].parent is set to r1.parent and fp[-8].live is set to
REG_LIVE_WRITTEN, because of the following code called in
check_stack_write_fixed_off():
static void save_register_state(struct bpf_func_state *state,
int spi, struct bpf_reg_state *reg,
int size)
{
...
state->stack[spi].spilled_ptr = *reg; // <--- parent & live copied
if (size == BPF_REG_SIZE)
state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
...
}
Note the intent to mark stack spill as written only if 8 bytes are
spilled to a slot, however this intent is spoiled by a 'live' field copy.
At (8) the checkpoint.fp[-8] should be marked as REG_LIVE_READ but
this does not happen:
- fp[-8] in a current state is already marked as REG_LIVE_WRITTEN;
- fp[-8].parent points to checkpoint.r1, parentage chain is used by
mark_reg_read() to mark checkpoint states.
At (10) the verification is finished for path 1-10 and jump 4-6 is
examined. The checkpoint.fp[-8] never gets REG_LIVE_READ mark and this
spill is pruned from the cached states by clean_live_states(). Hence
verifier state obtained via path 1-4,6 is deemed identical to one
obtained via path 1-6 and program marked as safe.
Note: the example should be executed with BPF_F_TEST_STATE_FREQ flag
set to force creation of intermediate verifier states.
This commit revisits the locations where bpf_reg_state instances are
copied and replaces the direct copies with a call to a function
copy_register_state(dst, src) that preserves 'parent' and 'live'
fields of the 'dst'.
Fixes: 679c782de1 ("bpf/verifier: per-register parent pointers")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230106142214.1040390-2-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
According to the definition of sizes[NUM_CACHES], when the size passed
to bpf_mem_cache_size() is 256, it should return 6 instead 7.
Fixes: 7c8199e24f ("bpf: Introduce any context BPF specific memory allocator.")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20230118084630.3750680-1-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently we allow to load any tracing program as sleepable,
but BPF_TRACE_RAW_TP can't sleep. Making the check explicit
for tracing programs attach types, so sleepable BPF_TRACE_RAW_TP
will fail to load.
Updating the verifier error to mention iter programs as well.
Acked-by: Song Liu <song@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230117223705.440975-1-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
To mitigate Spectre v4, 2039f26f3a ("bpf: Fix leakage due to
insufficient speculative store bypass mitigation") inserts lfence
instructions after 1) initializing a stack slot and 2) spilling a
pointer to the stack.
However, this does not cover cases where a stack slot is first
initialized with a pointer (subject to sanitization) but then
overwritten with a scalar (not subject to sanitization because
the slot was already initialized). In this case, the second write
may be subject to speculative store bypass (SSB) creating a
speculative pointer-as-scalar type confusion. This allows the
program to subsequently leak the numerical pointer value using,
for example, a branch-based cache side channel.
To fix this, also sanitize scalars if they write a stack slot
that previously contained a pointer. Assuming that pointer-spills
are only generated by LLVM on register-pressure, the performance
impact on most real-world BPF programs should be small.
The following unprivileged BPF bytecode drafts a minimal exploit
and the mitigation:
[...]
// r6 = 0 or 1 (skalar, unknown user input)
// r7 = accessible ptr for side channel
// r10 = frame pointer (fp), to be leaked
//
r9 = r10 # fp alias to encourage ssb
*(u64 *)(r9 - 8) = r10 // fp[-8] = ptr, to be leaked
// lfence added here because of pointer spill to stack.
//
// Ommitted: Dummy bpf_ringbuf_output() here to train alias predictor
// for no r9-r10 dependency.
//
*(u64 *)(r10 - 8) = r6 // fp[-8] = scalar, overwrites ptr
// 2039f26f3a: no lfence added because stack slot was not STACK_INVALID,
// store may be subject to SSB
//
// fix: also add an lfence when the slot contained a ptr
//
r8 = *(u64 *)(r9 - 8)
// r8 = architecturally a scalar, speculatively a ptr
//
// leak ptr using branch-based cache side channel:
r8 &= 1 // choose bit to leak
if r8 == 0 goto SLOW // no mispredict
// architecturally dead code if input r6 is 0,
// only executes speculatively iff ptr bit is 1
r8 = *(u64 *)(r7 + 0) # encode bit in cache (0: slow, 1: fast)
SLOW:
[...]
After running this, the program can time the access to *(r7 + 0) to
determine whether the chosen pointer bit was 0 or 1. Repeat this 64
times to recover the whole address on amd64.
In summary, sanitization can only be skipped if one scalar is
overwritten with another scalar. Scalar-confusion due to speculative
store bypass can not lead to invalid accesses because the pointer
bounds deducted during verification are enforced using branchless
logic. See 979d63d50c ("bpf: prevent out of bounds speculation on
pointer arithmetic") for details.
Do not make the mitigation depend on !env->allow_{uninit_stack,ptr_leaks}
because speculative leaks are likely unexpected if these were enabled.
For example, leaking the address to a protected log file may be acceptable
while disabling the mitigation might unintentionally leak the address
into the cached-state of a map that is accessible to unprivileged
processes.
Fixes: 2039f26f3a ("bpf: Fix leakage due to insufficient speculative store bypass mitigation")
Signed-off-by: Luis Gerhorst <gerhorst@cs.fau.de>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Henriette Hofmeier <henriette.hofmeier@rub.de>
Link: https://lore.kernel.org/bpf/edc95bad-aada-9cfc-ffe2-fa9bb206583c@cs.fau.de
Link: https://lore.kernel.org/bpf/20230109150544.41465-1-gerhorst@cs.fau.de
The deadlock still may occur while accessed in NMI and non-NMI
context. Because in NMI, we still may access the same bucket but with
different map_locked index.
For example, on the same CPU, .max_entries = 2, we update the hash map,
with key = 4, while running bpf prog in NMI nmi_handle(), to update
hash map with key = 20, so it will have the same bucket index but have
different map_locked index.
To fix this issue, using min mask to hash again.
Fixes: 20b6cc34ea ("bpf: Avoid hashtab deadlock with map_locked")
Signed-off-by: Tonghao Zhang <tong@infragraf.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Song Liu <song@kernel.org>
Cc: Yonghong Song <yhs@fb.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Stanislav Fomichev <sdf@google.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Hou Tao <houtao1@huawei.com>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20230111092903.92389-1-tong@infragraf.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Enabling CONFIG_MODULE_ALLOW_BTF_MISMATCH is an indication that BTF
mismatches are expected and module loading should proceed
anyway. Logging with pr_warn() on every one of these "benign"
mismatches creates unnecessary noise when many such modules are
loaded. Instead, handle this case with a single log warning that BTF
info may be unavailable.
Mismatches also result in calls to __btf_verifier_log() via
__btf_verifier_log_type() or btf_verifier_log_member(), adding several
additional lines of logging per mismatched module. Add checks to these
paths to skip logging for module BTF mismatches in the "allow
mismatch" case.
All existing logging behavior is preserved in the default
CONFIG_MODULE_ALLOW_BTF_MISMATCH=n case.
Signed-off-by: Connor O'Brien <connoro@google.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20230107025331.3240536-1-connoro@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
It was determined that the do_idr_lock parameter to
bpf_prog_free_id() was not necessary as it should always be true.
Suggested-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230106154400.74211-2-paul@paul-moore.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When changing the ebpf program put() routines to support being called
from within IRQ context the program ID was reset to zero prior to
calling the perf event and audit UNLOAD record generators, which
resulted in problems as the ebpf program ID was bogus (always zero).
This patch addresses this problem by removing an unnecessary call to
bpf_prog_free_id() in __bpf_prog_offload_destroy() and adjusting
__bpf_prog_put() to only call bpf_prog_free_id() after audit and perf
have finished their bpf program unload tasks in
bpf_prog_put_deferred(). For the record, no one can determine, or
remember, why it was necessary to free the program ID, and remove it
from the IDR, prior to executing bpf_prog_put_deferred();
regardless, both Stanislav and Alexei agree that the approach in this
patch should be safe.
It is worth noting that when moving the bpf_prog_free_id() call, the
do_idr_lock parameter was forced to true as the ebpf devs determined
this was the correct as the do_idr_lock should always be true. The
do_idr_lock parameter will be removed in a follow-up patch, but it
was kept here to keep the patch small in an effort to ease any stable
backports.
I also modified the bpf_audit_prog() logic used to associate the
AUDIT_BPF record with other associated records, e.g. @ctx != NULL.
Instead of keying off the operation, it now keys off the execution
context, e.g. '!in_irg && !irqs_disabled()', which is much more
appropriate and should help better connect the UNLOAD operations with
the associated audit state (other audit records).
Cc: stable@vger.kernel.org
Fixes: d809e134be ("bpf: Prepare bpf_prog_put() to be called from irq context.")
Reported-by: Burn Alting <burn.alting@iinet.net.au>
Reported-by: Jiri Olsa <olsajiri@gmail.com>
Suggested-by: Stanislav Fomichev <sdf@google.com>
Suggested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230106154400.74211-1-paul@paul-moore.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The verifier skips invalid kfunc call in check_kfunc_call(), which
would be captured in fixup_kfunc_call() if such insn is not eliminated
by dead code elimination. However, this can lead to the following
warning in backtrack_insn(), also see [1]:
------------[ cut here ]------------
verifier backtracking bug
WARNING: CPU: 6 PID: 8646 at kernel/bpf/verifier.c:2756 backtrack_insn
kernel/bpf/verifier.c:2756
__mark_chain_precision kernel/bpf/verifier.c:3065
mark_chain_precision kernel/bpf/verifier.c:3165
adjust_reg_min_max_vals kernel/bpf/verifier.c:10715
check_alu_op kernel/bpf/verifier.c:10928
do_check kernel/bpf/verifier.c:13821 [inline]
do_check_common kernel/bpf/verifier.c:16289
[...]
So make backtracking conservative with this by returning ENOTSUPP.
[1] https://lore.kernel.org/bpf/CACkBjsaXNceR8ZjkLG=dT3P=4A8SBsg0Z5h5PWLryF5=ghKq=g@mail.gmail.com/
Reported-by: syzbot+4da3ff23081bafe74fc2@syzkaller.appspotmail.com
Signed-off-by: Hao Sun <sunhao.th@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20230104014709.9375-1-sunhao.th@gmail.com
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:
====================
bpf-next 2023-01-04
We've added 45 non-merge commits during the last 21 day(s) which contain
a total of 50 files changed, 1454 insertions(+), 375 deletions(-).
The main changes are:
1) Fixes, improvements and refactoring of parts of BPF verifier's
state equivalence checks, from Andrii Nakryiko.
2) Fix a few corner cases in libbpf's BTF-to-C converter in particular
around padding handling and enums, also from Andrii Nakryiko.
3) Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to better
support decap on GRE tunnel devices not operating in collect metadata,
from Christian Ehrig.
4) Improve x86 JIT's codegen for PROBE_MEM runtime error checks,
from Dave Marchevsky.
5) Remove the need for trace_printk_lock for bpf_trace_printk
and bpf_trace_vprintk helpers, from Jiri Olsa.
6) Add proper documentation for BPF_MAP_TYPE_SOCK{MAP,HASH} maps,
from Maryam Tahhan.
7) Improvements in libbpf's btf_parse_elf error handling, from Changbin Du.
8) Bigger batch of improvements to BPF tracing code samples,
from Daniel T. Lee.
9) Add LoongArch support to libbpf's bpf_tracing helper header,
from Hengqi Chen.
10) Fix a libbpf compiler warning in perf_event_open_probe on arm32,
from Khem Raj.
11) Optimize bpf_local_storage_elem by removing 56 bytes of padding,
from Martin KaFai Lau.
12) Use pkg-config to locate libelf for resolve_btfids build,
from Shen Jiamin.
13) Various libbpf improvements around API documentation and errno
handling, from Xin Liu.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (45 commits)
libbpf: Return -ENODATA for missing btf section
libbpf: Add LoongArch support to bpf_tracing.h
libbpf: Restore errno after pr_warn.
libbpf: Added the description of some API functions
libbpf: Fix invalid return address register in s390
samples/bpf: Use BPF_KSYSCALL macro in syscall tracing programs
samples/bpf: Fix tracex2 by using BPF_KSYSCALL macro
samples/bpf: Change _kern suffix to .bpf with syscall tracing program
samples/bpf: Use vmlinux.h instead of implicit headers in syscall tracing program
samples/bpf: Use kyscall instead of kprobe in syscall tracing program
bpf: rename list_head -> graph_root in field info types
libbpf: fix errno is overwritten after being closed.
bpf: fix regs_exact() logic in regsafe() to remap IDs correctly
bpf: perform byte-by-byte comparison only when necessary in regsafe()
bpf: reject non-exact register type matches in regsafe()
bpf: generalize MAYBE_NULL vs non-MAYBE_NULL rule
bpf: reorganize struct bpf_reg_state fields
bpf: teach refsafe() to take into account ID remapping
bpf: Remove unused field initialization in bpf's ctl_table
selftests/bpf: Add jit probe_mem corner case tests to s390x denylist
...
====================
Link: https://lore.kernel.org/r/20230105000926.31350-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Many of the structs recently added to track field info for linked-list
head are useful as-is for rbtree root. So let's do a mechanical renaming
of list_head-related types and fields:
include/linux/bpf.h:
struct btf_field_list_head -> struct btf_field_graph_root
list_head -> graph_root in struct btf_field union
kernel/bpf/btf.c:
list_head -> graph_root in struct btf_field_info
This is a nonfunctional change, functionality to actually use these
fields for rbtree will be added in further patches.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20221217082506.1570898-5-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Instead of counting on prior allocations to have sized allocations to
the next kmalloc bucket size, always perform a krealloc that is at least
ksize(dst) in size (which is a no-op), so the size can be correctly
tracked by all the various allocation size trackers (KASAN,
__alloc_size, etc).
Reported-by: Hyunwoo Kim <v4bel@theori.io>
Link: https://lore.kernel.org/bpf/20221223094551.GA1439509@ubuntu
Fixes: ceb35b666d ("bpf/verifier: Use kmalloc_size_roundup() to match ksize() usage")
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Song Liu <song@kernel.org>
Cc: Yonghong Song <yhs@fb.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Stanislav Fomichev <sdf@google.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: bpf@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20221223182836.never.866-kees@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Fix the system crash that happens when a task iterator travel through
vma of tasks.
In task iterators, we used to access mm by following the pointer on
the task_struct; however, the death of a task will clear the pointer,
even though we still hold the task_struct. That can cause an
unexpected crash for a null pointer when an iterator is visiting a
task that dies during the visit. Keeping a reference of mm on the
iterator ensures we always have a valid pointer to mm.
Co-developed-by: Song Liu <song@kernel.org>
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Kui-Feng Lee <kuifeng@meta.com>
Reported-by: Nathan Slingerland <slinger@meta.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221216221855.4122288-2-kuifeng@meta.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In the scenario where livepatch and kretfunc coexist, the pageattr of
im->image is rox after arch_prepare_bpf_trampoline in
bpf_trampoline_update, and then modify_fentry or register_fentry returns
-EAGAIN from bpf_tramp_ftrace_ops_func, the BPF_TRAMP_F_ORIG_STACK flag
will be configured, and arch_prepare_bpf_trampoline will be re-executed.
At this time, because the pageattr of im->image is rox,
arch_prepare_bpf_trampoline will read and write im->image, which causes
a fault. as follows:
insmod livepatch-sample.ko # samples/livepatch/livepatch-sample.c
bpftrace -e 'kretfunc:cmdline_proc_show {}'
BUG: unable to handle page fault for address: ffffffffa0206000
PGD 322d067 P4D 322d067 PUD 322e063 PMD 1297e067 PTE d428061
Oops: 0003 [#1] PREEMPT SMP PTI
CPU: 2 PID: 270 Comm: bpftrace Tainted: G E K 6.1.0 #5
RIP: 0010:arch_prepare_bpf_trampoline+0xed/0x8c0
RSP: 0018:ffffc90001083ad8 EFLAGS: 00010202
RAX: ffffffffa0206000 RBX: 0000000000000020 RCX: 0000000000000000
RDX: ffffffffa0206001 RSI: ffffffffa0206000 RDI: 0000000000000030
RBP: ffffc90001083b70 R08: 0000000000000066 R09: ffff88800f51b400
R10: 000000002e72c6e5 R11: 00000000d0a15080 R12: ffff8880110a68c8
R13: 0000000000000000 R14: ffff88800f51b400 R15: ffffffff814fec10
FS: 00007f87bc0dc780(0000) GS:ffff88803e600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffa0206000 CR3: 0000000010b70000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
bpf_trampoline_update+0x25a/0x6b0
__bpf_trampoline_link_prog+0x101/0x240
bpf_trampoline_link_prog+0x2d/0x50
bpf_tracing_prog_attach+0x24c/0x530
bpf_raw_tp_link_attach+0x73/0x1d0
__sys_bpf+0x100e/0x2570
__x64_sys_bpf+0x1c/0x30
do_syscall_64+0x5b/0x80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
With this patch, when modify_fentry or register_fentry returns -EAGAIN
from bpf_tramp_ftrace_ops_func, the pageattr of im->image will be reset
to nx+rw.
Cc: stable@vger.kernel.org
Fixes: 00963a2e75 ("bpf: Support bpf_trampoline on functions with IPMODIFY (e.g. livepatch)")
Signed-off-by: Chuang Wang <nashuiliang@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20221224133146.780578-1-nashuiliang@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Extract byte-by-byte comparison of bpf_reg_state in regsafe() into
a helper function, which makes it more convenient to use it "on demand"
only for registers that benefit from such checks, instead of doing it
all the time, even if result of such comparison is ignored.
Also, remove WARN_ON_ONCE(1)+return false dead code. There is no risk of
missing some case as compiler will warn about non-void function not
returning value in some branches (and that under assumption that default
case is removed in the future).
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221223054921.958283-6-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Generalize the (somewhat implicit) rule of regsafe(), which states that
if register types in old and current states do not match *exactly*, they
can't be safely considered equivalent.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221223054921.958283-5-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Make generic check to prevent XXX_OR_NULL and XXX register types to be
intermixed. While technically in some situations it could be safe, it's
impossible to enforce due to the loss of an ID when converting
XXX_OR_NULL to its non-NULL variant. So prevent this in general, not
just for PTR_TO_MAP_KEY and PTR_TO_MAP_VALUE.
PTR_TO_MAP_KEY_OR_NULL and PTR_TO_MAP_VALUE_OR_NULL checks, which were
previously special-cased, are simplified to generic check that takes
into account range_within() and tnum_in(). This is correct as BPF
verifier doesn't allow arithmetic on XXX_OR_NULL register types, so
var_off and ranges should stay zero. But even if in the future this
restriction is lifted, it's even more important to enforce that var_off
and ranges are compatible, otherwise it's possible to construct case
where this can be exploited to bypass verifier's memory range safety
checks.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221223054921.958283-4-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Move id and ref_obj_id fields after scalar data section (var_off and
ranges). This is necessary to simplify next patch which will change
regsafe()'s logic to be safer, as it makes the contents that has to be
an exact match (type-specific parts, off, type, and var_off+ranges)
a single sequential block of memory, while id and ref_obj_id should
always be remapped and thus can't be memcp()'ed.
There are few places that assume that var_off is after id/ref_obj_id to
clear out id/ref_obj_id with the single memset(0). These are changed to
explicitly zero-out id/ref_obj_id fields. Other places are adjusted to
preserve exact byte-by-byte comparison behavior.
No functional changes.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221223054921.958283-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
states_equal() check performs ID mapping between old and new states to
establish a 1-to-1 correspondence between IDs, even if their absolute
numberic values across two equivalent states differ. This is important
both for correctness and to avoid unnecessary work when two states are
equivalent.
With recent changes we partially fixed this logic by maintaining ID map
across all function frames. This patch also makes refsafe() check take
into account (and maintain) ID map, making states_equal() behavior more
optimal and correct.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221223054921.958283-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Merge tag 'for-netdev' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Daniel Borkmann says:
====================
The following pull-request contains BPF updates for your *net* tree.
We've added 7 non-merge commits during the last 5 day(s) which contain
a total of 11 files changed, 231 insertions(+), 3 deletions(-).
The main changes are:
1) Fix a splat in bpf_skb_generic_pop() under CHECKSUM_PARTIAL due to
misuse of skb_postpull_rcsum(), from Jakub Kicinski with test case
from Martin Lau.
2) Fix BPF verifier's nullness propagation when registers are of
type PTR_TO_BTF_ID, from Hao Sun.
3) Fix bpftool build for JIT disassembler under statically built
libllvm, from Anton Protopopov.
4) Fix warnings reported by resolve_btfids when building vmlinux
with CONFIG_SECURITY_NETWORK disabled, from Hou Tao.
5) Minor fix up for BPF selftest gitignore, from Stanislav Fomichev.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
After befae75856, the verifier would propagate null information after
JEQ/JNE, e.g., if two pointers, one is maybe_null and the other is not,
the former would be marked as non-null in eq path. However, as comment
"PTR_TO_BTF_ID points to a kernel struct that does not need to be null
checked by the BPF program ... The verifier must keep this in mind and
can make no assumptions about null or non-null when doing branch ...".
If one pointer is maybe_null and the other is PTR_TO_BTF, the former is
incorrectly marked non-null. The following BPF prog can trigger a
null-ptr-deref, also see this report for more details[1]:
0: (18) r1 = map_fd ; R1_w=map_ptr(ks=4, vs=4)
2: (79) r6 = *(u64 *)(r1 +8) ; R6_w=bpf_map->inner_map_data
; R6 is PTR_TO_BTF_ID
; equals to null at runtime
3: (bf) r2 = r10
4: (07) r2 += -4
5: (62) *(u32 *)(r2 +0) = 0
6: (85) call bpf_map_lookup_elem#1 ; R0_w=map_value_or_null
7: (1d) if r6 == r0 goto pc+1
8: (95) exit
; from 7 to 9: R0=map_value R6=ptr_bpf_map
9: (61) r0 = *(u32 *)(r0 +0) ; null-ptr-deref
10: (95) exit
So, make the verifier propagate nullness information for reg to reg
comparisons only if neither reg is PTR_TO_BTF_ID.
[1] https://lore.kernel.org/bpf/CACkBjsaFJwjC5oiw-1KXvcazywodwXo4zGYsRHwbr2gSG9WcSw@mail.gmail.com/T/#u
Fixes: befae75856 ("bpf: propagate nullness information for reg to reg comparisons")
Signed-off-by: Hao Sun <sunhao.th@gmail.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221222024414.29539-1-sunhao.th@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Maxlen is used by standard proc_handlers such as proc_dointvec(), but in this
case we have our own proc_handler via bpf_stats_handler(). Therefore, remove
the initialization.
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20221221-bpf-syscall-v1-0-9550f5f2c3fc@chromium.org
'struct bpf_local_storage_elem' has an unused 56 byte padding at the
end due to struct's cache-line alignment requirement. This padding
space is overlapped by storage value contents, so if we use sizeof()
to calculate the total size, we overinflate it by 56 bytes. Use
offsetof() instead to calculate more exact memory use.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221221013036.3427431-1-martin.lau@linux.dev
Both bpf_trace_printk and bpf_trace_vprintk helpers use static buffer guarded
with trace_printk_lock spin lock.
The spin lock contention causes issues with bpf programs attached to
contention_begin tracepoint [1][2].
Andrii suggested we could get rid of the contention by using trylock, but we
could actually get rid of the spinlock completely by using percpu buffers the
same way as for bin_args in bpf_bprintf_prepare function.
Adding new return 'buf' argument to struct bpf_bprintf_data and making
bpf_bprintf_prepare to return also the buffer for printk helpers.
[1] https://lore.kernel.org/bpf/CACkBjsakT_yWxnSWr4r-0TpPvbKm9-OBmVUhJb7hV3hY8fdCkw@mail.gmail.com/
[2] https://lore.kernel.org/bpf/CACkBjsaCsTovQHFfkqJKto6S4Z8d02ud1D7MPESrHa1cVNNTrw@mail.gmail.com/
Reported-by: Hao Sun <sunhao.th@gmail.com>
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20221215214430.1336195-4-jolsa@kernel.org
Currently we always cleanup/decrement bpf_bprintf_nest_level variable
in bpf_bprintf_cleanup if it's > 0.
There's possible scenario where this could cause a problem, when
bpf_bprintf_prepare does not get bin_args buffer (because num_args is 0)
and following bpf_bprintf_cleanup call decrements bpf_bprintf_nest_level
variable, like:
in task context:
bpf_bprintf_prepare(num_args != 0) increments 'bpf_bprintf_nest_level = 1'
-> first irq :
bpf_bprintf_prepare(num_args == 0)
bpf_bprintf_cleanup decrements 'bpf_bprintf_nest_level = 0'
-> second irq:
bpf_bprintf_prepare(num_args != 0) bpf_bprintf_nest_level = 1
gets same buffer as task context above
Adding check to bpf_bprintf_cleanup and doing the real cleanup only if we
got bin_args data in the first place.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20221215214430.1336195-3-jolsa@kernel.org
Adding struct bpf_bprintf_data to hold bin_args argument for
bpf_bprintf_prepare function.
We will add another return argument to bpf_bprintf_prepare and
pass the struct to bpf_bprintf_cleanup for proper cleanup in
following changes.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20221215214430.1336195-2-jolsa@kernel.org
There are warnings reported from resolve_btfids when building vmlinux
with CONFIG_SECURITY_NETWORK disabled:
WARN: resolve_btfids: unresolved symbol bpf_lsm_sk_free_security
WARN: resolve_btfids: unresolved symbol bpf_lsm_sk_alloc_security
So only define BTF IDs for these LSM hooks when CONFIG_SECURITY_NETWORK
is enabled.
Fixes: c0c852dd18 ("bpf: Do not mark certain LSM hook arguments as trusted")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20221217062144.2507222-1-houtao@huaweicloud.com
* Randomize the per-cpu entry areas
Cleanups:
* Have CR3_ADDR_MASK use PHYSICAL_PAGE_MASK instead of open
coding it
* Move to "native" set_memory_rox() helper
* Clean up pmd_get_atomic() and i386-PAE
* Remove some unused page table size macros
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Merge tag 'x86_mm_for_6.2_v2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 mm updates from Dave Hansen:
"New Feature:
- Randomize the per-cpu entry areas
Cleanups:
- Have CR3_ADDR_MASK use PHYSICAL_PAGE_MASK instead of open coding it
- Move to "native" set_memory_rox() helper
- Clean up pmd_get_atomic() and i386-PAE
- Remove some unused page table size macros"
* tag 'x86_mm_for_6.2_v2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (35 commits)
x86/mm: Ensure forced page table splitting
x86/kasan: Populate shadow for shared chunk of the CPU entry area
x86/kasan: Add helpers to align shadow addresses up and down
x86/kasan: Rename local CPU_ENTRY_AREA variables to shorten names
x86/mm: Populate KASAN shadow for entire per-CPU range of CPU entry area
x86/mm: Recompute physical address for every page of per-CPU CEA mapping
x86/mm: Rename __change_page_attr_set_clr(.checkalias)
x86/mm: Inhibit _PAGE_NX changes from cpa_process_alias()
x86/mm: Untangle __change_page_attr_set_clr(.checkalias)
x86/mm: Add a few comments
x86/mm: Fix CR3_ADDR_MASK
x86/mm: Remove P*D_PAGE_MASK and P*D_PAGE_SIZE macros
mm: Convert __HAVE_ARCH_P..P_GET to the new style
mm: Remove pointless barrier() after pmdp_get_lockless()
x86/mm/pae: Get rid of set_64bit()
x86_64: Remove pointless set_64bit() usage
x86/mm/pae: Be consistent with pXXp_get_and_clear()
x86/mm/pae: Use WRITE_ONCE()
x86/mm/pae: Don't (ab)use atomic64
mm/gup: Fix the lockless PMD access
...
The bpf_prog_map_compatible() check makes sure that BPF program types are
not mixed inside BPF map types that can contain programs (tail call maps,
cpumaps and devmaps). It does this by setting the fields of the map->owner
struct to the values of the first program being checked against, and
rejecting any subsequent programs if the values don't match.
One of the values being set in the map owner struct is the program type,
and since the code did not resolve the prog type for fext programs, the map
owner type would be set to PROG_TYPE_EXT and subsequent loading of programs
of the target type into the map would fail.
This bug is seen in particular for XDP programs that are loaded as
PROG_TYPE_EXT using libxdp; these cannot insert programs into devmaps and
cpumaps because the check fails as described above.
Fix the bug by resolving the fext program type to its target program type
as elsewhere in the verifier.
v3:
- Add Yonghong's ACK
Fixes: f45d5b6ce2 ("bpf: generalise tail call map compatibility check")
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/r/20221214230254.790066-1-toke@redhat.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Hao Sun reported crash in dispatcher image [1].
Currently we don't have any sync between bpf_dispatcher_update and
bpf_dispatcher_xdp_func, so following race is possible:
cpu 0: cpu 1:
bpf_prog_run_xdp
...
bpf_dispatcher_xdp_func
in image at offset 0x0
bpf_dispatcher_update
update image at offset 0x800
bpf_dispatcher_update
update image at offset 0x0
in image at offset 0x0 -> crash
Fixing this by synchronizing dispatcher image update (which is done
in bpf_dispatcher_update function) with bpf_dispatcher_xdp_func that
reads and execute the dispatcher image.
Calling synchronize_rcu after updating and installing new image ensures
that readers leave old image before it's changed in the next dispatcher
update. The update itself is locked with dispatcher's mutex.
The bpf_prog_run_xdp is called under local_bh_disable and synchronize_rcu
will wait for it to leave [2].
[1] https://lore.kernel.org/bpf/Y5SFho7ZYXr9ifRn@krava/T/#m00c29ece654bc9f332a17df493bbca33e702896c
[2] https://lore.kernel.org/bpf/0B62D35A-E695-4B7A-A0D4-774767544C1A@gmail.com/T/#mff43e2c003ae99f4a38f353c7969be4c7162e877
Reported-by: Hao Sun <sunhao.th@gmail.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/20221214123542.1389719-1-jolsa@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
In [0], we added the ability to bpf_prog_attach LSM programs to cgroups,
but in our validation to make sure the prog is meant to be attached to
BPF_LSM_CGROUP, we return too early if the check fails. This results in
lack of decrementing prog's refcnt (through bpf_prog_put)
leaving the LSM program alive past the point of the expected lifecycle.
This fix allows for the decrement to take place.
[0] https://lore.kernel.org/all/20220628174314.1216643-4-sdf@google.com/
Fixes: 69fd337a97 ("bpf: per-cgroup lsm flavor")
Signed-off-by: Milan Landaverde <milan@mdaverde.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20221213175714.31963-1-milan@mdaverde.com
Core
----
- Allow live renaming when an interface is up
- Add retpoline wrappers for tc, improving considerably the
performances of complex queue discipline configurations.
- Add inet drop monitor support.
- A few GRO performance improvements.
- Add infrastructure for atomic dev stats, addressing long standing
data races.
- De-duplicate common code between OVS and conntrack offloading
infrastructure.
- A bunch of UBSAN_BOUNDS/FORTIFY_SOURCE improvements.
- Netfilter: introduce packet parser for tunneled packets
- Replace IPVS timer-based estimators with kthreads to scale up
the workload with the number of available CPUs.
- Add the helper support for connection-tracking OVS offload.
BPF
---
- Support for user defined BPF objects: the use case is to allocate
own objects, build own object hierarchies and use the building
blocks to build own data structures flexibly, for example, linked
lists in BPF.
- Make cgroup local storage available to non-cgroup attached BPF
programs.
- Avoid unnecessary deadlock detection and failures wrt BPF task
storage helpers.
- A relevant bunch of BPF verifier fixes and improvements.
- Veristat tool improvements to support custom filtering, sorting,
and replay of results.
- Add LLVM disassembler as default library for dumping JITed code.
- Lots of new BPF documentation for various BPF maps.
- Add bpf_rcu_read_{,un}lock() support for sleepable programs.
- Add RCU grace period chaining to BPF to wait for the completion
of access from both sleepable and non-sleepable BPF programs.
- Add support storing struct task_struct objects as kptrs in maps.
- Improve helper UAPI by explicitly defining BPF_FUNC_xxx integer
values.
- Add libbpf *_opts API-variants for bpf_*_get_fd_by_id() functions.
Protocols
---------
- TCP: implement Protective Load Balancing across switch links.
- TCP: allow dynamically disabling TCP-MD5 static key, reverting
back to fast[er]-path.
- UDP: Introduce optional per-netns hash lookup table.
- IPv6: simplify and cleanup sockets disposal.
- Netlink: support different type policies for each generic
netlink operation.
- MPTCP: add MSG_FASTOPEN and FastOpen listener side support.
- MPTCP: add netlink notification support for listener sockets
events.
- SCTP: add VRF support, allowing sctp sockets binding to VRF
devices.
- Add bridging MAC Authentication Bypass (MAB) support.
- Extensions for Ethernet VPN bridging implementation to better
support multicast scenarios.
- More work for Wi-Fi 7 support, comprising conversion of all
the existing drivers to internal TX queue usage.
- IPSec: introduce a new offload type (packet offload) allowing
complete header processing and crypto offloading.
- IPSec: extended ack support for more descriptive XFRM error
reporting.
- RXRPC: increase SACK table size and move processing into a
per-local endpoint kernel thread, reducing considerably the
required locking.
- IEEE 802154: synchronous send frame and extended filtering
support, initial support for scanning available 15.4 networks.
- Tun: bump the link speed from 10Mbps to 10Gbps.
- Tun/VirtioNet: implement UDP segmentation offload support.
Driver API
----------
- PHY/SFP: improve power level switching between standard
level 1 and the higher power levels.
- New API for netdev <-> devlink_port linkage.
- PTP: convert existing drivers to new frequency adjustment
implementation.
- DSA: add support for rx offloading.
- Autoload DSA tagging driver when dynamically changing protocol.
- Add new PCP and APPTRUST attributes to Data Center Bridging.
- Add configuration support for 800Gbps link speed.
- Add devlink port function attribute to enable/disable RoCE and
migratable.
- Extend devlink-rate to support strict prioriry and weighted fair
queuing.
- Add devlink support to directly reading from region memory.
- New device tree helper to fetch MAC address from nvmem.
- New big TCP helper to simplify temporary header stripping.
New hardware / drivers
----------------------
- Ethernet:
- Marvel Octeon CNF95N and CN10KB Ethernet Switches.
- Marvel Prestera AC5X Ethernet Switch.
- WangXun 10 Gigabit NIC.
- Motorcomm yt8521 Gigabit Ethernet.
- Microchip ksz9563 Gigabit Ethernet Switch.
- Microsoft Azure Network Adapter.
- Linux Automation 10Base-T1L adapter.
- PHY:
- Aquantia AQR112 and AQR412.
- Motorcomm YT8531S.
- PTP:
- Orolia ART-CARD.
- WiFi:
- MediaTek Wi-Fi 7 (802.11be) devices.
- RealTek rtw8821cu, rtw8822bu, rtw8822cu and rtw8723du USB
devices.
- Bluetooth:
- Broadcom BCM4377/4378/4387 Bluetooth chipsets.
- Realtek RTL8852BE and RTL8723DS.
- Cypress.CYW4373A0 WiFi + Bluetooth combo device.
Drivers
-------
- CAN:
- gs_usb: bus error reporting support.
- kvaser_usb: listen only and bus error reporting support.
- Ethernet NICs:
- Intel (100G):
- extend action skbedit to RX queue mapping.
- implement devlink-rate support.
- support direct read from memory.
- nVidia/Mellanox (mlx5):
- SW steering improvements, increasing rules update rate.
- Support for enhanced events compression.
- extend H/W offload packet manipulation capabilities.
- implement IPSec packet offload mode.
- nVidia/Mellanox (mlx4):
- better big TCP support.
- Netronome Ethernet NICs (nfp):
- IPsec offload support.
- add support for multicast filter.
- Broadcom:
- RSS and PTP support improvements.
- AMD/SolarFlare:
- netlink extened ack improvements.
- add basic flower matches to offload, and related stats.
- Virtual NICs:
- ibmvnic: introduce affinity hint support.
- small / embedded:
- FreeScale fec: add initial XDP support.
- Marvel mv643xx_eth: support MII/GMII/RGMII modes for Kirkwood.
- TI am65-cpsw: add suspend/resume support.
- Mediatek MT7986: add RX wireless wthernet dispatch support.
- Realtek 8169: enable GRO software interrupt coalescing per
default.
- Ethernet high-speed switches:
- Microchip (sparx5):
- add support for Sparx5 TC/flower H/W offload via VCAP.
- Mellanox mlxsw:
- add 802.1X and MAC Authentication Bypass offload support.
- add ip6gre support.
- Embedded Ethernet switches:
- Mediatek (mtk_eth_soc):
- improve PCS implementation, add DSA untag support.
- enable flow offload support.
- Renesas:
- add rswitch R-Car Gen4 gPTP support.
- Microchip (lan966x):
- add full XDP support.
- add TC H/W offload via VCAP.
- enable PTP on bridge interfaces.
- Microchip (ksz8):
- add MTU support for KSZ8 series.
- Qualcomm 802.11ax WiFi (ath11k):
- support configuring channel dwell time during scan.
- MediaTek WiFi (mt76):
- enable Wireless Ethernet Dispatch (WED) offload support.
- add ack signal support.
- enable coredump support.
- remain_on_channel support.
- Intel WiFi (iwlwifi):
- enable Wi-Fi 7 Extremely High Throughput (EHT) PHY capabilities.
- 320 MHz channels support.
- RealTek WiFi (rtw89):
- new dynamic header firmware format support.
- wake-over-WLAN support.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Merge tag 'net-next-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
Pull networking updates from Paolo Abeni:
"Core:
- Allow live renaming when an interface is up
- Add retpoline wrappers for tc, improving considerably the
performances of complex queue discipline configurations
- Add inet drop monitor support
- A few GRO performance improvements
- Add infrastructure for atomic dev stats, addressing long standing
data races
- De-duplicate common code between OVS and conntrack offloading
infrastructure
- A bunch of UBSAN_BOUNDS/FORTIFY_SOURCE improvements
- Netfilter: introduce packet parser for tunneled packets
- Replace IPVS timer-based estimators with kthreads to scale up the
workload with the number of available CPUs
- Add the helper support for connection-tracking OVS offload
BPF:
- Support for user defined BPF objects: the use case is to allocate
own objects, build own object hierarchies and use the building
blocks to build own data structures flexibly, for example, linked
lists in BPF
- Make cgroup local storage available to non-cgroup attached BPF
programs
- Avoid unnecessary deadlock detection and failures wrt BPF task
storage helpers
- A relevant bunch of BPF verifier fixes and improvements
- Veristat tool improvements to support custom filtering, sorting,
and replay of results
- Add LLVM disassembler as default library for dumping JITed code
- Lots of new BPF documentation for various BPF maps
- Add bpf_rcu_read_{,un}lock() support for sleepable programs
- Add RCU grace period chaining to BPF to wait for the completion of
access from both sleepable and non-sleepable BPF programs
- Add support storing struct task_struct objects as kptrs in maps
- Improve helper UAPI by explicitly defining BPF_FUNC_xxx integer
values
- Add libbpf *_opts API-variants for bpf_*_get_fd_by_id() functions
Protocols:
- TCP: implement Protective Load Balancing across switch links
- TCP: allow dynamically disabling TCP-MD5 static key, reverting back
to fast[er]-path
- UDP: Introduce optional per-netns hash lookup table
- IPv6: simplify and cleanup sockets disposal
- Netlink: support different type policies for each generic netlink
operation
- MPTCP: add MSG_FASTOPEN and FastOpen listener side support
- MPTCP: add netlink notification support for listener sockets events
- SCTP: add VRF support, allowing sctp sockets binding to VRF devices
- Add bridging MAC Authentication Bypass (MAB) support
- Extensions for Ethernet VPN bridging implementation to better
support multicast scenarios
- More work for Wi-Fi 7 support, comprising conversion of all the
existing drivers to internal TX queue usage
- IPSec: introduce a new offload type (packet offload) allowing
complete header processing and crypto offloading
- IPSec: extended ack support for more descriptive XFRM error
reporting
- RXRPC: increase SACK table size and move processing into a
per-local endpoint kernel thread, reducing considerably the
required locking
- IEEE 802154: synchronous send frame and extended filtering support,
initial support for scanning available 15.4 networks
- Tun: bump the link speed from 10Mbps to 10Gbps
- Tun/VirtioNet: implement UDP segmentation offload support
Driver API:
- PHY/SFP: improve power level switching between standard level 1 and
the higher power levels
- New API for netdev <-> devlink_port linkage
- PTP: convert existing drivers to new frequency adjustment
implementation
- DSA: add support for rx offloading
- Autoload DSA tagging driver when dynamically changing protocol
- Add new PCP and APPTRUST attributes to Data Center Bridging
- Add configuration support for 800Gbps link speed
- Add devlink port function attribute to enable/disable RoCE and
migratable
- Extend devlink-rate to support strict prioriry and weighted fair
queuing
- Add devlink support to directly reading from region memory
- New device tree helper to fetch MAC address from nvmem
- New big TCP helper to simplify temporary header stripping
New hardware / drivers:
- Ethernet:
- Marvel Octeon CNF95N and CN10KB Ethernet Switches
- Marvel Prestera AC5X Ethernet Switch
- WangXun 10 Gigabit NIC
- Motorcomm yt8521 Gigabit Ethernet
- Microchip ksz9563 Gigabit Ethernet Switch
- Microsoft Azure Network Adapter
- Linux Automation 10Base-T1L adapter
- PHY:
- Aquantia AQR112 and AQR412
- Motorcomm YT8531S
- PTP:
- Orolia ART-CARD
- WiFi:
- MediaTek Wi-Fi 7 (802.11be) devices
- RealTek rtw8821cu, rtw8822bu, rtw8822cu and rtw8723du USB
devices
- Bluetooth:
- Broadcom BCM4377/4378/4387 Bluetooth chipsets
- Realtek RTL8852BE and RTL8723DS
- Cypress.CYW4373A0 WiFi + Bluetooth combo device
Drivers:
- CAN:
- gs_usb: bus error reporting support
- kvaser_usb: listen only and bus error reporting support
- Ethernet NICs:
- Intel (100G):
- extend action skbedit to RX queue mapping
- implement devlink-rate support
- support direct read from memory
- nVidia/Mellanox (mlx5):
- SW steering improvements, increasing rules update rate
- Support for enhanced events compression
- extend H/W offload packet manipulation capabilities
- implement IPSec packet offload mode
- nVidia/Mellanox (mlx4):
- better big TCP support
- Netronome Ethernet NICs (nfp):
- IPsec offload support
- add support for multicast filter
- Broadcom:
- RSS and PTP support improvements
- AMD/SolarFlare:
- netlink extened ack improvements
- add basic flower matches to offload, and related stats
- Virtual NICs:
- ibmvnic: introduce affinity hint support
- small / embedded:
- FreeScale fec: add initial XDP support
- Marvel mv643xx_eth: support MII/GMII/RGMII modes for Kirkwood
- TI am65-cpsw: add suspend/resume support
- Mediatek MT7986: add RX wireless wthernet dispatch support
- Realtek 8169: enable GRO software interrupt coalescing per
default
- Ethernet high-speed switches:
- Microchip (sparx5):
- add support for Sparx5 TC/flower H/W offload via VCAP
- Mellanox mlxsw:
- add 802.1X and MAC Authentication Bypass offload support
- add ip6gre support
- Embedded Ethernet switches:
- Mediatek (mtk_eth_soc):
- improve PCS implementation, add DSA untag support
- enable flow offload support
- Renesas:
- add rswitch R-Car Gen4 gPTP support
- Microchip (lan966x):
- add full XDP support
- add TC H/W offload via VCAP
- enable PTP on bridge interfaces
- Microchip (ksz8):
- add MTU support for KSZ8 series
- Qualcomm 802.11ax WiFi (ath11k):
- support configuring channel dwell time during scan
- MediaTek WiFi (mt76):
- enable Wireless Ethernet Dispatch (WED) offload support
- add ack signal support
- enable coredump support
- remain_on_channel support
- Intel WiFi (iwlwifi):
- enable Wi-Fi 7 Extremely High Throughput (EHT) PHY capabilities
- 320 MHz channels support
- RealTek WiFi (rtw89):
- new dynamic header firmware format support
- wake-over-WLAN support"
* tag 'net-next-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2002 commits)
ipvs: fix type warning in do_div() on 32 bit
net: lan966x: Remove a useless test in lan966x_ptp_add_trap()
net: ipa: add IPA v4.7 support
dt-bindings: net: qcom,ipa: Add SM6350 compatible
bnxt: Use generic HBH removal helper in tx path
IPv6/GRO: generic helper to remove temporary HBH/jumbo header in driver
selftests: forwarding: Add bridge MDB test
selftests: forwarding: Rename bridge_mdb test
bridge: mcast: Support replacement of MDB port group entries
bridge: mcast: Allow user space to specify MDB entry routing protocol
bridge: mcast: Allow user space to add (*, G) with a source list and filter mode
bridge: mcast: Add support for (*, G) with a source list and filter mode
bridge: mcast: Avoid arming group timer when (S, G) corresponds to a source
bridge: mcast: Add a flag for user installed source entries
bridge: mcast: Expose __br_multicast_del_group_src()
bridge: mcast: Expose br_multicast_new_group_src()
bridge: mcast: Add a centralized error path
bridge: mcast: Place netlink policy before validation functions
bridge: mcast: Split (*, G) and (S, G) addition into different functions
bridge: mcast: Do not derive entry type from its filter mode
...
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Merge tag 'random-6.2-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random
Pull random number generator updates from Jason Donenfeld:
- Replace prandom_u32_max() and various open-coded variants of it,
there is now a new family of functions that uses fast rejection
sampling to choose properly uniformly random numbers within an
interval:
get_random_u32_below(ceil) - [0, ceil)
get_random_u32_above(floor) - (floor, U32_MAX]
get_random_u32_inclusive(floor, ceil) - [floor, ceil]
Coccinelle was used to convert all current users of
prandom_u32_max(), as well as many open-coded patterns, resulting in
improvements throughout the tree.
I'll have a "late" 6.1-rc1 pull for you that removes the now unused
prandom_u32_max() function, just in case any other trees add a new
use case of it that needs to converted. According to linux-next,
there may be two trivial cases of prandom_u32_max() reintroductions
that are fixable with a 's/.../.../'. So I'll have for you a final
conversion patch doing that alongside the removal patch during the
second week.
This is a treewide change that touches many files throughout.
- More consistent use of get_random_canary().
- Updates to comments, documentation, tests, headers, and
simplification in configuration.
- The arch_get_random*_early() abstraction was only used by arm64 and
wasn't entirely useful, so this has been replaced by code that works
in all relevant contexts.
- The kernel will use and manage random seeds in non-volatile EFI
variables, refreshing a variable with a fresh seed when the RNG is
initialized. The RNG GUID namespace is then hidden from efivarfs to
prevent accidental leakage.
These changes are split into random.c infrastructure code used in the
EFI subsystem, in this pull request, and related support inside of
EFISTUB, in Ard's EFI tree. These are co-dependent for full
functionality, but the order of merging doesn't matter.
- Part of the infrastructure added for the EFI support is also used for
an improvement to the way vsprintf initializes its siphash key,
replacing an sleep loop wart.
- The hardware RNG framework now always calls its correct random.c
input function, add_hwgenerator_randomness(), rather than sometimes
going through helpers better suited for other cases.
- The add_latent_entropy() function has long been called from the fork
handler, but is a no-op when the latent entropy gcc plugin isn't
used, which is fine for the purposes of latent entropy.
But it was missing out on the cycle counter that was also being mixed
in beside the latent entropy variable. So now, if the latent entropy
gcc plugin isn't enabled, add_latent_entropy() will expand to a call
to add_device_randomness(NULL, 0), which adds a cycle counter,
without the absent latent entropy variable.
- The RNG is now reseeded from a delayed worker, rather than on demand
when used. Always running from a worker allows it to make use of the
CPU RNG on platforms like S390x, whose instructions are too slow to
do so from interrupts. It also has the effect of adding in new inputs
more frequently with more regularity, amounting to a long term
transcript of random values. Plus, it helps a bit with the upcoming
vDSO implementation (which isn't yet ready for 6.2).
- The jitter entropy algorithm now tries to execute on many different
CPUs, round-robining, in hopes of hitting even more memory latencies
and other unpredictable effects. It also will mix in a cycle counter
when the entropy timer fires, in addition to being mixed in from the
main loop, to account more explicitly for fluctuations in that timer
firing. And the state it touches is now kept within the same cache
line, so that it's assured that the different execution contexts will
cause latencies.
* tag 'random-6.2-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random: (23 commits)
random: include <linux/once.h> in the right header
random: align entropy_timer_state to cache line
random: mix in cycle counter when jitter timer fires
random: spread out jitter callback to different CPUs
random: remove extraneous period and add a missing one in comments
efi: random: refresh non-volatile random seed when RNG is initialized
vsprintf: initialize siphash key using notifier
random: add back async readiness notifier
random: reseed in delayed work rather than on-demand
random: always mix cycle counter in add_latent_entropy()
hw_random: use add_hwgenerator_randomness() for early entropy
random: modernize documentation comment on get_random_bytes()
random: adjust comment to account for removed function
random: remove early archrandom abstraction
random: use random.trust_{bootloader,cpu} command line option only
stackprotector: actually use get_random_canary()
stackprotector: move get_random_canary() into stackprotector.h
treewide: use get_random_u32_inclusive() when possible
treewide: use get_random_u32_{above,below}() instead of manual loop
treewide: use get_random_u32_below() instead of deprecated function
...
An update for verifier.c:states_equal()/regsafe() to use check_ids()
for active spin lock comparisons. This fixes the issue reported by
Kumar Kartikeya Dwivedi in [1] using technique suggested by Edward Cree.
W/o this commit the verifier might be tricked to accept the following
program working with a map containing spin locks:
0: r9 = map_lookup_elem(...) ; Returns PTR_TO_MAP_VALUE_OR_NULL id=1.
1: r8 = map_lookup_elem(...) ; Returns PTR_TO_MAP_VALUE_OR_NULL id=2.
2: if r9 == 0 goto exit ; r9 -> PTR_TO_MAP_VALUE.
3: if r8 == 0 goto exit ; r8 -> PTR_TO_MAP_VALUE.
4: r7 = ktime_get_ns() ; Unbound SCALAR_VALUE.
5: r6 = ktime_get_ns() ; Unbound SCALAR_VALUE.
6: bpf_spin_lock(r8) ; active_lock.id == 2.
7: if r6 > r7 goto +1 ; No new information about the state
; is derived from this check, thus
; produced verifier states differ only
; in 'insn_idx'.
8: r9 = r8 ; Optionally make r9.id == r8.id.
--- checkpoint --- ; Assume is_state_visisted() creates a
; checkpoint here.
9: bpf_spin_unlock(r9) ; (a,b) active_lock.id == 2.
; (a) r9.id == 2, (b) r9.id == 1.
10: exit(0)
Consider two verification paths:
(a) 0-10
(b) 0-7,9-10
The path (a) is verified first. If checkpoint is created at (8)
the (b) would assume that (8) is safe because regsafe() does not
compare register ids for registers of type PTR_TO_MAP_VALUE.
[1] https://lore.kernel.org/bpf/20221111202719.982118-1-memxor@gmail.com/
Reported-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Suggested-by: Edward Cree <ecree.xilinx@gmail.com>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20221209135733.28851-6-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
verifier.c:states_equal() must maintain register ID mapping across all
function frames. Otherwise the following example might be erroneously
marked as safe:
main:
fp[-24] = map_lookup_elem(...) ; frame[0].fp[-24].id == 1
fp[-32] = map_lookup_elem(...) ; frame[0].fp[-32].id == 2
r1 = &fp[-24]
r2 = &fp[-32]
call foo()
r0 = 0
exit
foo:
0: r9 = r1
1: r8 = r2
2: r7 = ktime_get_ns()
3: r6 = ktime_get_ns()
4: if (r6 > r7) goto skip_assign
5: r9 = r8
skip_assign: ; <--- checkpoint
6: r9 = *r9 ; (a) frame[1].r9.id == 2
; (b) frame[1].r9.id == 1
7: if r9 == 0 goto exit: ; mark_ptr_or_null_regs() transfers != 0 info
; for all regs sharing ID:
; (a) r9 != 0 => &frame[0].fp[-32] != 0
; (b) r9 != 0 => &frame[0].fp[-24] != 0
8: r8 = *r8 ; (a) r8 == &frame[0].fp[-32]
; (b) r8 == &frame[0].fp[-32]
9: r0 = *r8 ; (a) safe
; (b) unsafe
exit:
10: exit
While processing call to foo() verifier considers the following
execution paths:
(a) 0-10
(b) 0-4,6-10
(There is also path 0-7,10 but it is not interesting for the issue at
hand. (a) is verified first.)
Suppose that checkpoint is created at (6) when path (a) is verified,
next path (b) is verified and (6) is reached.
If states_equal() maintains separate 'idmap' for each frame the
mapping at (6) for frame[1] would be empty and
regsafe(r9)::check_ids() would add a pair 2->1 and return true,
which is an error.
If states_equal() maintains single 'idmap' for all frames the mapping
at (6) would be { 1->1, 2->2 } and regsafe(r9)::check_ids() would
return false when trying to add a pair 2->1.
This issue was suggested in the following discussion:
https://lore.kernel.org/bpf/CAEf4BzbFB5g4oUfyxk9rHy-PJSLQ3h8q9mV=rVoXfr_JVm8+1Q@mail.gmail.com/
Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20221209135733.28851-4-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The verifier.c:regsafe() has the following shortcut:
equal = memcmp(rold, rcur, offsetof(struct bpf_reg_state, parent)) == 0;
...
if (equal)
return true;
Which is executed regardless old register type. This is incorrect for
register types that might have an ID checked by check_ids(), namely:
- PTR_TO_MAP_KEY
- PTR_TO_MAP_VALUE
- PTR_TO_PACKET_META
- PTR_TO_PACKET
The following pattern could be used to exploit this:
0: r9 = map_lookup_elem(...) ; Returns PTR_TO_MAP_VALUE_OR_NULL id=1.
1: r8 = map_lookup_elem(...) ; Returns PTR_TO_MAP_VALUE_OR_NULL id=2.
2: r7 = ktime_get_ns() ; Unbound SCALAR_VALUE.
3: r6 = ktime_get_ns() ; Unbound SCALAR_VALUE.
4: if r6 > r7 goto +1 ; No new information about the state
; is derived from this check, thus
; produced verifier states differ only
; in 'insn_idx'.
5: r9 = r8 ; Optionally make r9.id == r8.id.
--- checkpoint --- ; Assume is_state_visisted() creates a
; checkpoint here.
6: if r9 == 0 goto <exit> ; Nullness info is propagated to all
; registers with matching ID.
7: r1 = *(u64 *) r8 ; Not always safe.
Verifier first visits path 1-7 where r8 is verified to be not null
at (6). Later the jump from 4 to 6 is examined. The checkpoint for (6)
looks as follows:
R8_rD=map_value_or_null(id=2,off=0,ks=4,vs=8,imm=0)
R9_rwD=map_value_or_null(id=2,off=0,ks=4,vs=8,imm=0)
R10=fp0
The current state is:
R0=... R6=... R7=... fp-8=...
R8=map_value_or_null(id=2,off=0,ks=4,vs=8,imm=0)
R9=map_value_or_null(id=1,off=0,ks=4,vs=8,imm=0)
R10=fp0
Note that R8 states are byte-to-byte identical, so regsafe() would
exit early and skip call to check_ids(), thus ID mapping 2->2 will not
be added to 'idmap'. Next, states for R9 are compared: these are not
identical and check_ids() is executed, but 'idmap' is empty, so
check_ids() adds mapping 2->1 to 'idmap' and returns success.
This commit pushes the 'equal' down to register types that don't need
check_ids().
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20221209135733.28851-2-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
It may happen that destination buffer memory overlaps with memory dynptr
points to. Hence, we must use memmove to correctly copy from dynptr to
destination buffer, or source buffer to dynptr.
This actually isn't a problem right now, as memcpy implementation falls
back to memmove on detecting overlap and warns about it, but we
shouldn't be relying on that.
Acked-by: Joanne Koong <joannelkoong@gmail.com>
Acked-by: David Vernet <void@manifault.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221207204141.308952-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
After previous commit, we are minimizing helper specific assumptions
from check_func_arg_reg_off, making it generic, and offloading checks
for a specific argument type to their respective functions called after
check_func_arg_reg_off has been called.
This allows relying on a consistent set of guarantees after that call
and then relying on them in code that deals with registers for each
argument type later. This is in line with how process_spin_lock,
process_timer_func, process_kptr_func check reg->var_off to be constant.
The same reasoning is used here to move the alignment check into
process_dynptr_func. Note that it also needs to check for constant
var_off, and accumulate the constant var_off when computing the spi in
get_spi, but that fix will come in later changes.
Acked-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221207204141.308952-6-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
While check_func_arg_reg_off is the place which performs generic checks
needed by various candidates of reg->type, there is some handling for
special cases, like ARG_PTR_TO_DYNPTR, OBJ_RELEASE, and
ARG_PTR_TO_RINGBUF_MEM.
This commit aims to streamline these special cases and instead leave
other things up to argument type specific code to handle. The function
will be restrictive by default, and cover all possible cases when
OBJ_RELEASE is set, without having to update the function again (and
missing to do that being a bug).
This is done primarily for two reasons: associating back reg->type to
its argument leaves room for the list getting out of sync when a new
reg->type is supported by an arg_type.
The other case is ARG_PTR_TO_RINGBUF_MEM. The problem there is something
we already handle, whenever a release argument is expected, it should
be passed as the pointer that was received from the acquire function.
Hence zero fixed and variable offset.
There is nothing special about ARG_PTR_TO_RINGBUF_MEM, where technically
its target register type PTR_TO_MEM | MEM_RINGBUF can already be passed
with non-zero offset to other helper functions, which makes sense.
Hence, lift the arg_type_is_release check for reg->off and cover all
possible register types, instead of duplicating the same kind of check
twice for current OBJ_RELEASE arg_types (alloc_mem and ptr_to_btf_id).
For the release argument, arg_type_is_dynptr is the special case, where
we go to actual object being freed through the dynptr, so the offset of
the pointer still needs to allow fixed and variable offset and
process_dynptr_func will verify them later for the release argument case
as well.
This is not specific to ARG_PTR_TO_DYNPTR though, we will need to make
this exception for any future object on the stack that needs to be
released. In this sense, PTR_TO_STACK as a candidate for object on stack
argument is a special case for release offset checks, and they need to
be done by the helper releasing the object on stack.
Since the check has been lifted above all register type checks, remove
the duplicated check that is being done for PTR_TO_BTF_ID.
Acked-by: Joanne Koong <joannelkoong@gmail.com>
Acked-by: David Vernet <void@manifault.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221207204141.308952-5-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Recently, user ringbuf support introduced a PTR_TO_DYNPTR register type
for use in callback state, because in case of user ringbuf helpers,
there is no dynptr on the stack that is passed into the callback. To
reflect such a state, a special register type was created.
However, some checks have been bypassed incorrectly during the addition
of this feature. First, for arg_type with MEM_UNINIT flag which
initialize a dynptr, they must be rejected for such register type.
Secondly, in the future, there are plans to add dynptr helpers that
operate on the dynptr itself and may change its offset and other
properties.
In all of these cases, PTR_TO_DYNPTR shouldn't be allowed to be passed
to such helpers, however the current code simply returns 0.
The rejection for helpers that release the dynptr is already handled.
For fixing this, we take a step back and rework existing code in a way
that will allow fitting in all classes of helpers and have a coherent
model for dealing with the variety of use cases in which dynptr is used.
First, for ARG_PTR_TO_DYNPTR, it can either be set alone or together
with a DYNPTR_TYPE_* constant that denotes the only type it accepts.
Next, helpers which initialize a dynptr use MEM_UNINIT to indicate this
fact. To make the distinction clear, use MEM_RDONLY flag to indicate
that the helper only operates on the memory pointed to by the dynptr,
not the dynptr itself. In C parlance, it would be equivalent to taking
the dynptr as a point to const argument.
When either of these flags are not present, the helper is allowed to
mutate both the dynptr itself and also the memory it points to.
Currently, the read only status of the memory is not tracked in the
dynptr, but it would be trivial to add this support inside dynptr state
of the register.
With these changes and renaming PTR_TO_DYNPTR to CONST_PTR_TO_DYNPTR to
better reflect its usage, it can no longer be passed to helpers that
initialize a dynptr, i.e. bpf_dynptr_from_mem, bpf_ringbuf_reserve_dynptr.
A note to reviewers is that in code that does mark_stack_slots_dynptr,
and unmark_stack_slots_dynptr, we implicitly rely on the fact that
PTR_TO_STACK reg is the only case that can reach that code path, as one
cannot pass CONST_PTR_TO_DYNPTR to helpers that don't set MEM_RDONLY. In
both cases such helpers won't be setting that flag.
The next patch will add a couple of selftest cases to make sure this
doesn't break.
Fixes: 2057156738 ("bpf: Add bpf_user_ringbuf_drain() helper")
Acked-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221207204141.308952-4-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
ARG_PTR_TO_DYNPTR is akin to ARG_PTR_TO_TIMER, ARG_PTR_TO_KPTR, where
the underlying register type is subjected to more special checks to
determine the type of object represented by the pointer and its state
consistency.
Move dynptr checks to their own 'process_dynptr_func' function so that
is consistent and in-line with existing code. This also makes it easier
to reuse this code for kfunc handling.
Then, reuse this consolidated function in kfunc dynptr handling too.
Note that for kfuncs, the arg_type constraint of DYNPTR_TYPE_LOCAL has
been lifted.
Acked-by: David Vernet <void@manifault.com>
Acked-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221207204141.308952-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
If there are pending rcu callback, free_mem_alloc() will use
rcu_barrier_tasks_trace() and rcu_barrier() to wait for the pending
__free_rcu_tasks_trace() and __free_rcu() callback.
If rcu_trace_implies_rcu_gp() is true, there will be no pending
__free_rcu(), so it will be OK to skip rcu_barrier() as well.
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20221209010947.3130477-3-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When there are batched freeing operations on a specific CPU, part of
the freed elements ((high_watermark - lower_watermark) / 2 + 1) will be
indirectly moved into waiting_for_gp list through free_by_rcu list.
After call_rcu_in_progress becomes false again, the remaining elements
in free_by_rcu list will be moved to waiting_for_gp list by the next
invocation of free_bulk(). However if the expiration of RCU tasks trace
grace period is relatively slow, none element in free_by_rcu list will
be moved.
So instead of invoking __alloc_percpu_gfp() or kmalloc_node() to
allocate a new object, in alloc_bulk() just check whether or not there is
freed element in free_by_rcu list and reuse it if available.
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20221209010947.3130477-2-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
insn->imm for kfunc is the relative address of __bpf_call_base,
instead of __bpf_base_call, Fix the comment error.
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Link: https://lore.kernel.org/r/20221208013724.257848-1-yangjihong1@huawei.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In BPF all global functions, and BPF helpers return a 64-bit
value. For kfunc calls, this is not the case, and they can return
e.g. 32-bit values.
The return register R0 for kfuncs calls can therefore be marked as
subreg_def != DEF_NOT_SUBREG. In general, if a register is marked with
subreg_def != DEF_NOT_SUBREG, some archs (where bpf_jit_needs_zext()
returns true) require the verifier to insert explicit zero-extension
instructions.
For kfuncs calls, however, the caller should do sign/zero extension
for return values. In other words, the compiler is responsible to
insert proper instructions, not the verifier.
An example, provided by Yonghong Song:
$ cat t.c
extern unsigned foo(void);
unsigned bar1(void) {
return foo();
}
unsigned bar2(void) {
if (foo()) return 10; else return 20;
}
$ clang -target bpf -mcpu=v3 -O2 -c t.c && llvm-objdump -d t.o
t.o: file format elf64-bpf
Disassembly of section .text:
0000000000000000 <bar1>:
0: 85 10 00 00 ff ff ff ff call -0x1
1: 95 00 00 00 00 00 00 00 exit
0000000000000010 <bar2>:
2: 85 10 00 00 ff ff ff ff call -0x1
3: bc 01 00 00 00 00 00 00 w1 = w0
4: b4 00 00 00 14 00 00 00 w0 = 0x14
5: 16 01 01 00 00 00 00 00 if w1 == 0x0 goto +0x1 <LBB1_2>
6: b4 00 00 00 0a 00 00 00 w0 = 0xa
0000000000000038 <LBB1_2>:
7: 95 00 00 00 00 00 00 00 exit
If the return value of 'foo()' is used in the BPF program, the proper
zero-extension will be done.
Currently, the verifier correctly marks, say, a 32-bit return value as
subreg_def != DEF_NOT_SUBREG, but will fail performing the actual
zero-extension, due to a verifier bug in
opt_subreg_zext_lo32_rnd_hi32(). load_reg is not properly set to R0,
and the following path will be taken:
if (WARN_ON(load_reg == -1)) {
verbose(env, "verifier bug. zext_dst is set, but no reg is defined\n");
return -EFAULT;
}
A longer discussion from v1 can be found in the link below.
Correct the verifier by avoiding doing explicit zero-extension of R0
for kfunc calls. Note that R0 will still be marked as a sub-register
for return values smaller than 64-bit.
Fixes: 83a2881903 ("bpf: Account for BPF_FETCH in insn_has_def32()")
Link: https://lore.kernel.org/bpf/20221202103620.1915679-1-bjorn@kernel.org/
Suggested-by: Yonghong Song <yhs@meta.com>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221207103540.396496-1-bjorn@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
bpf_cgroup_acquire(), bpf_cgroup_release(), bpf_cgroup_kptr_get(), and
bpf_cgroup_ancestor(), are kfuncs that were recently added to
kernel/bpf/helpers.c. These are "core" kfuncs in that they're available
for use in any tracepoint or struct_ops BPF program. Though they have no
ABI stability guarantees, we should still document them. This patch adds
a struct cgroup * subsection to the Core kfuncs section which describes
each of these kfuncs.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20221207204911.873646-3-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
bpf_task_acquire(), bpf_task_release(), and bpf_task_from_pid() are
kfuncs that were recently added to kernel/bpf/helpers.c. These are
"core" kfuncs in that they're available for use for any tracepoint or
struct_ops BPF program. Though they have no ABI stability guarantees, we
should still document them. This patch adds a new Core kfuncs section to
the BPF kfuncs doc, and adds entries for all of these task kfuncs.
Note that bpf_task_kptr_get() is not documented, as it still returns
NULL while we're working to resolve how it can use RCU to ensure struct
task_struct * lifetime.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20221207204911.873646-2-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Number of total instructions in BPF program (including subprogs) can and
is accessed from env->prog->len. visit_func_call_insn() doesn't do any
checks against insn_cnt anymore, relying on push_insn() to do this check
internally. So remove unnecessary insn_cnt input argument from
visit_func_call_insn() and visit_insn() functions.
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20221207195534.2866030-1-andrii@kernel.org
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Merge "do not rely on ALLOW_ERROR_INJECTION for fmod_ret" into bpf-next
Merge commit 5b481acab4 ("bpf: do not rely on ALLOW_ERROR_INJECTION for fmod_ret")
from hid tree into bpf-next.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The current way of expressing that a non-bpf kernel component is willing
to accept that bpf programs can be attached to it and that they can change
the return value is to abuse ALLOW_ERROR_INJECTION.
This is debated in the link below, and the result is that it is not a
reasonable thing to do.
Reuse the kfunc declaration structure to also tag the kernel functions
we want to be fmodret. This way we can control from any subsystem which
functions are being modified by bpf without touching the verifier.
Link: https://lore.kernel.org/all/20221121104403.1545f9b5@gandalf.local.home/
Suggested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20221206145936.922196-2-benjamin.tissoires@redhat.com
Don't mark some instructions as jump points when there are actually no
jumps and instructions are just processed sequentially. Such case is
handled naturally by precision backtracking logic without the need to
update jump history. See get_prev_insn_idx(). It goes back linearly by
one instruction, unless current top of jmp_history is pointing to
current instruction. In such case we use `st->jmp_history[cnt - 1].prev_idx`
to find instruction from which we jumped to the current instruction
non-linearly.
Also remove both jump and prune point marking for instruction right
after unconditional jumps, as program flow can get to the instruction
right after unconditional jump instruction only if there is a jump to
that instruction from somewhere else in the program. In such case we'll
mark such instruction as prune/jump point because it's a destination of
a jump.
This change has no changes in terms of number of instructions or states
processes across Cilium and selftests programs.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/r/20221206233345.438540-4-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Jump history updating and state equivalence checks are conceptually
independent, so move push_jmp_history() out of is_state_visited(). Also
make a decision whether to perform state equivalence checks or not one
layer higher in do_check(), keeping is_state_visited() unconditionally
performing state checks.
push_jmp_history() should be performed after state checks. There is just
one small non-uniformity. When is_state_visited() finds already
validated equivalent state, it propagates precision marks to current
state's parent chain. For this to work correctly, jump history has to be
updated, so is_state_visited() is doing that internally.
But if no equivalent verified state is found, jump history has to be
updated in a newly cloned child state, so is_jmp_point()
+ push_jmp_history() is performed after is_state_visited() exited with
zero result, which means "proceed with validation".
This change has no functional changes. It's not strictly necessary, but
feels right to decouple these two processes.
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221206233345.438540-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
BPF verifier marks some instructions as prune points. Currently these
prune points serve two purposes.
It's a point where verifier tries to find previously verified state and
check current state's equivalence to short circuit verification for
current code path.
But also currently it's a point where jump history, used for precision
backtracking, is updated. This is done so that non-linear flow of
execution could be properly backtracked.
Such coupling is coincidental and unnecessary. Some prune points are not
part of some non-linear jump path, so don't need update of jump history.
On the other hand, not all instructions which have to be recorded in
jump history necessarily are good prune points.
This patch splits prune and jump points into independent flags.
Currently all prune points are marked as jump points to minimize amount
of changes in this patch, but next patch will perform some optimization
of prune vs jmp point placement.
No functional changes are intended.
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221206233345.438540-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
btf->struct_meta_tab is populated by btf_parse_struct_metas in btf.c.
There, a BTF record is created for any type containing a spin_lock or
any next-gen datastructure node/head.
Currently, for non-MAP_VALUE types, reg_btf_record will only search for
a record using struct_meta_tab if the reg->type exactly matches
(PTR_TO_BTF_ID | MEM_ALLOC). This exact match is too strict: an
"allocated obj" type - returned from bpf_obj_new - might pick up other
flags while working its way through the program.
Loosen the check to be exact for base_type and just use MEM_ALLOC mask
for type_flag.
This patch is marked Fixes as the original intent of reg_btf_record was
unlikely to have been to fail finding btf_record for valid alloc obj
types with additional flags, some of which (e.g. PTR_UNTRUSTED)
are valid register type states for alloc obj independent of this series.
However, I didn't find a specific broken repro case outside of this
series' added functionality, so it's possible that nothing was
triggering this logic error before.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
cc: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Fixes: 4e814da0d5 ("bpf: Allow locking bpf_spin_lock in allocated objects")
Link: https://lore.kernel.org/r/20221206231000.3180914-2-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
A series of prior patches added some kfuncs that allow struct
task_struct * objects to be used as kptrs. These kfuncs leveraged the
'refcount_t rcu_users' field of the task for performing refcounting.
This field was used instead of 'refcount_t usage', as we wanted to
leverage the safety provided by RCU for ensuring a task's lifetime.
A struct task_struct is refcounted by two different refcount_t fields:
1. p->usage: The "true" refcount field which task lifetime. The
task is freed as soon as this refcount drops to 0.
2. p->rcu_users: An "RCU users" refcount field which is statically
initialized to 2, and is co-located in a union with
a struct rcu_head field (p->rcu). p->rcu_users
essentially encapsulates a single p->usage
refcount, and when p->rcu_users goes to 0, an RCU
callback is scheduled on the struct rcu_head which
decrements the p->usage refcount.
Our logic was that by using p->rcu_users, we would be able to use RCU to
safely issue refcount_inc_not_zero() a task's rcu_users field to
determine if a task could still be acquired, or was exiting.
Unfortunately, this does not work due to p->rcu_users and p->rcu sharing
a union. When p->rcu_users goes to 0, an RCU callback is scheduled to
drop a single p->usage refcount, and because the fields share a union,
the refcount immediately becomes nonzero again after the callback is
scheduled.
If we were to split the fields out of the union, this wouldn't be a
problem. Doing so should also be rather non-controversial, as there are
a number of places in struct task_struct that have padding which we
could use to avoid growing the structure by splitting up the fields.
For now, so as to fix the kfuncs to be correct, this patch instead
updates bpf_task_acquire() and bpf_task_release() to use the p->usage
field for refcounting via the get_task_struct() and put_task_struct()
functions. Because we can no longer rely on RCU, the change also guts
the bpf_task_acquire_not_zero() and bpf_task_kptr_get() functions
pending a resolution on the above problem.
In addition, the task fixes the kfunc and rcu_read_lock selftests to
expect this new behavior.
Fixes: 90660309b0 ("bpf: Add kfuncs for storing struct task_struct * as a kptr")
Fixes: fca1aa7551 ("bpf: Handle MEM_RCU type properly")
Reported-by: Matus Jokay <matus.jokay@stuba.sk>
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20221206210538.597606-1-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Similar to sk/inode/task local storage, enable sleepable support for
cgrp local storage.
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221201050444.2785007-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Martin mentioned that the verifier cannot assume arguments from
LSM hook sk_alloc_security being trusted since after the hook
is called, the sk ref_count is set to 1. This will overwrite
the ref_count changed by the bpf program and may cause ref_count
underflow later on.
I then further checked some other hooks. For example,
for bpf_lsm_file_alloc() hook in fs/file_table.c,
f->f_cred = get_cred(cred);
error = security_file_alloc(f);
if (unlikely(error)) {
file_free_rcu(&f->f_rcuhead);
return ERR_PTR(error);
}
atomic_long_set(&f->f_count, 1);
The input parameter 'f' to security_file_alloc() cannot be trusted
as well.
Specifically, I investiaged bpf_map/bpf_prog/file/sk/task alloc/free
lsm hooks. Except bpf_map_alloc and task_alloc, arguments for all other
hooks should not be considered as trusted. This may not be a complete
list, but it covers common usage for sk and task.
Fixes: 3f00c52393 ("bpf: Allow trusted pointers to be passed to KF_TRUSTED_ARGS kfuncs")
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221203204954.2043348-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Commit 9bb00b2895 ("bpf: Add kfunc bpf_rcu_read_lock/unlock()")
introduced MEM_RCU and bpf_rcu_read_lock/unlock() support. In that
commit, a rcu pointer is tagged with both MEM_RCU and PTR_TRUSTED
so that it can be passed into kfuncs or helpers as an argument.
Martin raised a good question in [1] such that the rcu pointer,
although being able to accessing the object, might have reference
count of 0. This might cause a problem if the rcu pointer is passed
to a kfunc which expects trusted arguments where ref count should
be greater than 0.
This patch makes the following changes related to MEM_RCU pointer:
- MEM_RCU pointer might be NULL (PTR_MAYBE_NULL).
- Introduce KF_RCU so MEM_RCU ptr can be acquired with
a KF_RCU tagged kfunc which assumes ref count of rcu ptr
could be zero.
- For mem access 'b = ptr->a', say 'ptr' is a MEM_RCU ptr, and
'a' is tagged with __rcu as well. Let us mark 'b' as
MEM_RCU | PTR_MAYBE_NULL.
[1] https://lore.kernel.org/bpf/ac70f574-4023-664e-b711-e0d3b18117fd@linux.dev/
Fixes: 9bb00b2895 ("bpf: Add kfunc bpf_rcu_read_lock/unlock()")
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221203184602.477272-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Consider a verifier state with three acquired references, all with
release_on_unlock = true:
idx 0 1 2
state->refs = [2 4 6]
(with 2, 4, and 6 being the ref ids).
When bpf_spin_unlock is called, process_spin_lock will loop through all
acquired_refs and, for each ref, if it's release_on_unlock, calls
release_reference on it. That function in turn calls
release_reference_state, which removes the reference from state->refs by
swapping the reference state with the last reference state in
refs array and decrements acquired_refs count.
process_spin_lock's loop logic, which is essentially:
for (i = 0; i < state->acquired_refs; i++) {
if (!state->refs[i].release_on_unlock)
continue;
release_reference(state->refs[i].id);
}
will fail to release release_on_unlock references which are swapped from
the end. Running this logic on our example demonstrates:
state->refs = [2 4 6] (start of idx=0 iter)
release state->refs[0] by swapping w/ state->refs[2]
state->refs = [6 4] (start of idx=1)
release state->refs[1], no need to swap as it's the last idx
state->refs = [6] (start of idx=2, loop terminates)
ref_id 6 should have been removed but was skipped.
Fix this by looping from back-to-front, which results in refs that are
candidates for removal being swapped with refs which have already been
examined and kept.
If we modify our initial example such that ref 6 is replaced with ref 7,
which is _not_ release_on_unlock, and loop from the back, we'd see:
state->refs = [2 4 7] (start of idx=2)
state->refs = [2 4 7] (start of idx=1)
state->refs = [2 7] (start of idx=0, refs 7 and 4 swapped)
state->refs = [7] (after idx=0, 7 and 2 swapped, loop terminates)
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
cc: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Fixes: 534e86bc6c ("bpf: Add 'release on unlock' logic for bpf_list_push_{front,back}")
Link: https://lore.kernel.org/r/20221201183406.1203621-1-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When building the kernel with clang lto (CONFIG_LTO_CLANG_FULL=y), the
following compilation error will appear:
$ make LLVM=1 LLVM_IAS=1 -j
...
ld.lld: error: ld-temp.o <inline asm>:26889:1: symbol 'cgroup_storage_map_btf_ids' is already defined
cgroup_storage_map_btf_ids:;
^
make[1]: *** [/.../bpf-next/scripts/Makefile.vmlinux_o:61: vmlinux.o] Error 1
In local_storage.c, we have
BTF_ID_LIST_SINGLE(cgroup_storage_map_btf_ids, struct, bpf_local_storage_map)
Commit c4bcfb38a9 ("bpf: Implement cgroup storage available to
non-cgroup-attached bpf progs") added the above identical BTF_ID_LIST_SINGLE
definition in bpf_cgrp_storage.c. With duplicated definitions, llvm linker
complains with lto build.
Also, extracting btf_id of 'struct bpf_local_storage_map' is defined four times
for sk, inode, task and cgrp local storages. Let us define a single global one
with a different name than cgroup_storage_map_btf_ids, which also fixed
the lto compilation error.
Fixes: c4bcfb38a9 ("bpf: Implement cgroup storage available to non-cgroup-attached bpf progs")
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221130052147.1591625-1-yhs@fb.com
The networking programs typically don't require CAP_PERFMON, but through kfuncs
like bpf_cast_to_kern_ctx() they can access memory through PTR_TO_BTF_ID. In
such case enforce CAP_PERFMON.
Also make sure that only GPL programs can access kernel data structures.
All kfuncs require GPL already.
Also remove allow_ptr_to_map_access. It's the same as allow_ptr_leaks and
different name for the same check only causes confusion.
Fixes: fd264ca020 ("bpf: Add a kfunc to type cast from bpf uapi ctx to kernel ctx")
Fixes: 50c6b8a9ae ("selftests/bpf: Add a test for btf_type_tag "percpu"")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20221125220617.26846-1-alexei.starovoitov@gmail.com
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Daniel Borkmann says:
====================
bpf-next 2022-11-25
We've added 101 non-merge commits during the last 11 day(s) which contain
a total of 109 files changed, 8827 insertions(+), 1129 deletions(-).
The main changes are:
1) Support for user defined BPF objects: the use case is to allocate own
objects, build own object hierarchies and use the building blocks to
build own data structures flexibly, for example, linked lists in BPF,
from Kumar Kartikeya Dwivedi.
2) Add bpf_rcu_read_{,un}lock() support for sleepable programs,
from Yonghong Song.
3) Add support storing struct task_struct objects as kptrs in maps,
from David Vernet.
4) Batch of BPF map documentation improvements, from Maryam Tahhan
and Donald Hunter.
5) Improve BPF verifier to propagate nullness information for branches
of register to register comparisons, from Eduard Zingerman.
6) Fix cgroup BPF iter infra to hold reference on the start cgroup,
from Hou Tao.
7) Fix BPF verifier to not mark fentry/fexit program arguments as trusted
given it is not the case for them, from Alexei Starovoitov.
8) Improve BPF verifier's realloc handling to better play along with dynamic
runtime analysis tools like KASAN and friends, from Kees Cook.
9) Remove legacy libbpf mode support from bpftool,
from Sahid Orentino Ferdjaoui.
10) Rework zero-len skb redirection checks to avoid potentially breaking
existing BPF test infra users, from Stanislav Fomichev.
11) Two small refactorings which are independent and have been split out
of the XDP queueing RFC series, from Toke Høiland-Jørgensen.
12) Fix a memory leak in LSM cgroup BPF selftest, from Wang Yufen.
13) Documentation on how to run BPF CI without patch submission,
from Daniel Müller.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
====================
Link: https://lore.kernel.org/r/20221125012450.441-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The PTR_TRUSTED flag should only be applied to pointers where the verifier can
guarantee that such pointers are valid.
The fentry/fexit/fmod_ret programs are not in this category.
Only arguments of SEC("tp_btf") and SEC("iter") programs are trusted
(which have BPF_TRACE_RAW_TP and BPF_TRACE_ITER attach_type correspondingly)
This bug was masked because convert_ctx_accesses() was converting trusted
loads into BPF_PROBE_MEM loads. Fix it as well.
The loads from trusted pointers don't need exception handling.
Fixes: 3f00c52393 ("bpf: Allow trusted pointers to be passed to KF_TRUSTED_ARGS kfuncs")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20221124215314.55890-1-alexei.starovoitov@gmail.com
Add two kfunc's bpf_rcu_read_lock() and bpf_rcu_read_unlock(). These two kfunc's
can be used for all program types. The following is an example about how
rcu pointer are used w.r.t. bpf_rcu_read_lock()/bpf_rcu_read_unlock().
struct task_struct {
...
struct task_struct *last_wakee;
struct task_struct __rcu *real_parent;
...
};
Let us say prog does 'task = bpf_get_current_task_btf()' to get a
'task' pointer. The basic rules are:
- 'real_parent = task->real_parent' should be inside bpf_rcu_read_lock
region. This is to simulate rcu_dereference() operation. The
'real_parent' is marked as MEM_RCU only if (1). task->real_parent is
inside bpf_rcu_read_lock region, and (2). task is a trusted ptr. So
MEM_RCU marked ptr can be 'trusted' inside the bpf_rcu_read_lock region.
- 'last_wakee = real_parent->last_wakee' should be inside bpf_rcu_read_lock
region since it tries to access rcu protected memory.
- the ptr 'last_wakee' will be marked as PTR_UNTRUSTED since in general
it is not clear whether the object pointed by 'last_wakee' is valid or
not even inside bpf_rcu_read_lock region.
The verifier will reset all rcu pointer register states to untrusted
at bpf_rcu_read_unlock() kfunc call site, so any such rcu pointer
won't be trusted any more outside the bpf_rcu_read_lock() region.
The current implementation does not support nested rcu read lock
region in the prog.
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221124053217.2373910-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Introduce bpf_func_proto->might_sleep to indicate a particular helper
might sleep. This will make later check whether a helper might be
sleepable or not easier.
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221124053211.2373553-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Callers can currently store tasks as kptrs using bpf_task_acquire(),
bpf_task_kptr_get(), and bpf_task_release(). These are useful if a
caller already has a struct task_struct *, but there may be some callers
who only have a pid, and want to look up the associated struct
task_struct * from that to e.g. find task->comm.
This patch therefore adds a new bpf_task_from_pid() kfunc which allows
BPF programs to get a struct task_struct * kptr from a pid.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20221122145300.251210-2-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Syzkaller managed to hit another decl_tag issue:
btf_func_proto_check kernel/bpf/btf.c:4506 [inline]
btf_check_all_types kernel/bpf/btf.c:4734 [inline]
btf_parse_type_sec+0x1175/0x1980 kernel/bpf/btf.c:4763
btf_parse kernel/bpf/btf.c:5042 [inline]
btf_new_fd+0x65a/0xb00 kernel/bpf/btf.c:6709
bpf_btf_load+0x6f/0x90 kernel/bpf/syscall.c:4342
__sys_bpf+0x50a/0x6c0 kernel/bpf/syscall.c:5034
__do_sys_bpf kernel/bpf/syscall.c:5093 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5091 [inline]
__x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5091
do_syscall_64+0x54/0x70 arch/x86/entry/common.c:48
This seems similar to commit ea68376c8b ("bpf: prevent decl_tag from being
referenced in func_proto") but for the argument.
Reported-by: syzbot+8dd0551dda6020944c5d@syzkaller.appspotmail.com
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20221123035422.872531-2-sdf@google.com
In commit fda01efc61 ("bpf: Enable cgroups to be used as kptrs"), I
added an 'int idx' variable to kfunc_init() which was meant to
dynamically set the index of the btf id entries of the
'generic_dtor_ids' array. This was done to make the code slightly less
brittle as the struct cgroup * kptr kfuncs such as bpf_cgroup_aquire()
are compiled out if CONFIG_CGROUPS is not defined. This, however, causes
an lkp build warning:
>> kernel/bpf/helpers.c:2005:40: warning: multiple unsequenced
modifications to 'idx' [-Wunsequenced]
.btf_id = generic_dtor_ids[idx++],
Fix the warning by just hard-coding the indices.
Fixes: fda01efc61 ("bpf: Enable cgroups to be used as kptrs")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: David Vernet <void@manifault.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221123135253.637525-1-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
struct cgroup * objects have a variably sized struct cgroup *ancestors[]
field which stores pointers to their ancestor cgroups. If using a cgroup
as a kptr, it can be useful to access these ancestors, but doing so
requires variable offset accesses for PTR_TO_BTF_ID, which is currently
unsupported.
This is a very useful field to access for cgroup kptrs, as programs may
wish to walk their ancestor cgroups when determining e.g. their
proportional cpu.weight. So as to enable this functionality with cgroup
kptrs before var_off is supported for PTR_TO_BTF_ID, this patch adds a
bpf_cgroup_ancestor() kfunc which accesses the cgroup node on behalf of
the caller, and acquires a reference on it. Once var_off is supported
for PTR_TO_BTF_ID, and fields inside a struct can be marked as trusted
so they retain the PTR_TRUSTED modifier when walked, this can be
removed.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20221122055458.173143-4-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Now that tasks can be used as kfuncs, and the PTR_TRUSTED flag is
available for us to easily add basic acquire / get / release kfuncs, we
can do the same for cgroups. This patch set adds the following kfuncs
which enable using cgroups as kptrs:
struct cgroup *bpf_cgroup_acquire(struct cgroup *cgrp);
struct cgroup *bpf_cgroup_kptr_get(struct cgroup **cgrpp);
void bpf_cgroup_release(struct cgroup *cgrp);
A follow-on patch will add a selftest suite which validates these
kfuncs.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20221122055458.173143-2-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
bpf_selem_alloc function is used by inode_storage, sk_storage and
task_storage maps to set map value, for these map types, there may
be a spin lock in the map value, so if we use memcpy to copy the whole
map value from user, the spin lock field may be initialized incorrectly.
Since the spin lock field is zeroed by kzalloc, call copy_map_value
instead of memcpy to skip copying the spin lock field to fix it.
Fixes: 6ac99e8f23 ("bpf: Introduce bpf sk local storage")
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Link: https://lore.kernel.org/r/20221114134720.1057939-2-xukuohai@huawei.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
bpf_iter_attach_cgroup() has already acquired an extra reference for the
start cgroup, but the reference may be released if the iterator link fd
is closed after the creation of iterator fd, and it may lead to
user-after-free problem when reading the iterator fd.
An alternative fix is pinning iterator link when opening iterator,
but it will make iterator link being still visible after the close of
iterator link fd and the behavior is different with other link types, so
just fixing it by acquiring another reference for the start cgroup.
Fixes: d4ccaf58a8 ("bpf: Introduce cgroup iter")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20221121073440.1828292-2-houtao@huaweicloud.com
Most allocation sites in the kernel want an explicitly sized allocation
(and not "more"), and that dynamic runtime analysis tools (e.g. KASAN,
UBSAN_BOUNDS, FORTIFY_SOURCE, etc) are looking for precise bounds checking
(i.e. not something that is rounded up). A tiny handful of allocations
were doing an implicit alloc/realloc loop that actually depended on
ksize(), and didn't actually always call realloc. This has created a
long series of bugs and problems over many years related to the runtime
bounds checking, so these callers are finally being adjusted to _not_
depend on the ksize() side-effect, by doing one of several things:
- tracking the allocation size precisely and just never calling ksize()
at all [1].
- always calling realloc and not using ksize() at all. (This solution
ends up actually be a subset of the next solution.)
- using kmalloc_size_roundup() to explicitly round up the desired
allocation size immediately [2].
The bpf/verifier case is this another of this latter case, and is the
last outstanding case to be fixed in the kernel.
Because some of the dynamic bounds checking depends on the size being an
_argument_ to an allocator function (i.e. see the __alloc_size attribute),
the ksize() users are rare, and it could waste local variables, it
was been deemed better to explicitly separate the rounding up from the
allocation itself [3].
Round up allocations with kmalloc_size_roundup() so that the verifier's
use of ksize() is always accurate.
[1] e.g.:
https://git.kernel.org/linus/712f210a457dhttps://git.kernel.org/linus/72c08d9f4c72
[2] e.g.:
https://git.kernel.org/netdev/net-next/c/12d6c1d3a2adhttps://git.kernel.org/netdev/net-next/c/ab3f7828c979https://git.kernel.org/netdev/net-next/c/d6dd508080a3
[3] https://lore.kernel.org/lkml/0ea1fc165a6c6117f982f4f135093e69cb884930.camel@redhat.com/
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20221118183409.give.387-kees@kernel.org
Implement bpf_rdonly_cast() which tries to cast the object
to a specified type. This tries to support use case like below:
#define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
where skb_end_pointer(SKB) is a 'unsigned char *' and needs to
be casted to 'struct skb_shared_info *'.
The signature of bpf_rdonly_cast() looks like
void *bpf_rdonly_cast(void *obj, __u32 btf_id)
The function returns the same 'obj' but with PTR_TO_BTF_ID with
btf_id. The verifier will ensure btf_id being a struct type.
Since the supported type cast may not reflect what the 'obj'
represents, the returned btf_id is marked as PTR_UNTRUSTED, so
the return value and subsequent pointer chasing cannot be
used as helper/kfunc arguments.
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221120195437.3114585-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Implement bpf_cast_to_kern_ctx() kfunc which does a type cast
of a uapi ctx object to the corresponding kernel ctx. Previously
if users want to access some data available in kctx but not
in uapi ctx, bpf_probe_read_kernel() helper is needed.
The introduction of bpf_cast_to_kern_ctx() allows direct
memory access which makes code simpler and easier to understand.
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221120195432.3113982-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Later on, we will introduce kfuncs bpf_cast_to_kern_ctx() and
bpf_rdonly_cast() which apply to all program types. Currently kfunc set
only supports individual prog types. This patch added support for kfunc
applying to all program types.
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221120195426.3113828-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In the unlikely event that bpf_global_ma is not correctly initialized,
instead of checking the boolean everytime bpf_obj_new_impl is called,
simply check it while loading the program and return an error if
bpf_global_ma_set is false.
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221120212610.2361700-1-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Now that BPF supports adding new kernel functions with kfuncs, and
storing kernel objects in maps with kptrs, we can add a set of kfuncs
which allow struct task_struct objects to be stored in maps as
referenced kptrs. The possible use cases for doing this are plentiful.
During tracing, for example, it would be useful to be able to collect
some tasks that performed a certain operation, and then periodically
summarize who they are, which cgroup they're in, how much CPU time
they've utilized, etc.
In order to enable this, this patch adds three new kfuncs:
struct task_struct *bpf_task_acquire(struct task_struct *p);
struct task_struct *bpf_task_kptr_get(struct task_struct **pp);
void bpf_task_release(struct task_struct *p);
A follow-on patch will add selftests validating these kfuncs.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20221120051004.3605026-4-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Kfuncs currently support specifying the KF_TRUSTED_ARGS flag to signal
to the verifier that it should enforce that a BPF program passes it a
"safe", trusted pointer. Currently, "safe" means that the pointer is
either PTR_TO_CTX, or is refcounted. There may be cases, however, where
the kernel passes a BPF program a safe / trusted pointer to an object
that the BPF program wishes to use as a kptr, but because the object
does not yet have a ref_obj_id from the perspective of the verifier, the
program would be unable to pass it to a KF_ACQUIRE | KF_TRUSTED_ARGS
kfunc.
The solution is to expand the set of pointers that are considered
trusted according to KF_TRUSTED_ARGS, so that programs can invoke kfuncs
with these pointers without getting rejected by the verifier.
There is already a PTR_UNTRUSTED flag that is set in some scenarios,
such as when a BPF program reads a kptr directly from a map
without performing a bpf_kptr_xchg() call. These pointers of course can
and should be rejected by the verifier. Unfortunately, however,
PTR_UNTRUSTED does not cover all the cases for safety that need to
be addressed to adequately protect kfuncs. Specifically, pointers
obtained by a BPF program "walking" a struct are _not_ considered
PTR_UNTRUSTED according to BPF. For example, say that we were to add a
kfunc called bpf_task_acquire(), with KF_ACQUIRE | KF_TRUSTED_ARGS, to
acquire a struct task_struct *. If we only used PTR_UNTRUSTED to signal
that a task was unsafe to pass to a kfunc, the verifier would mistakenly
allow the following unsafe BPF program to be loaded:
SEC("tp_btf/task_newtask")
int BPF_PROG(unsafe_acquire_task,
struct task_struct *task,
u64 clone_flags)
{
struct task_struct *acquired, *nested;
nested = task->last_wakee;
/* Would not be rejected by the verifier. */
acquired = bpf_task_acquire(nested);
if (!acquired)
return 0;
bpf_task_release(acquired);
return 0;
}
To address this, this patch defines a new type flag called PTR_TRUSTED
which tracks whether a PTR_TO_BTF_ID pointer is safe to pass to a
KF_TRUSTED_ARGS kfunc or a BPF helper function. PTR_TRUSTED pointers are
passed directly from the kernel as a tracepoint or struct_ops callback
argument. Any nested pointer that is obtained from walking a PTR_TRUSTED
pointer is no longer PTR_TRUSTED. From the example above, the struct
task_struct *task argument is PTR_TRUSTED, but the 'nested' pointer
obtained from 'task->last_wakee' is not PTR_TRUSTED.
A subsequent patch will add kfuncs for storing a task kfunc as a kptr,
and then another patch will add selftests to validate.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20221120051004.3605026-3-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
reg_type_str() in the verifier currently only allows a single register
type modifier to be present in the 'prefix' string which is eventually
stored in the env type_str_buf. This currently works fine because there
are no overlapping type modifiers, but once PTR_TRUSTED is added, that
will no longer be the case. This patch updates reg_type_str() to support
having multiple modifiers in the prefix string, and updates the size of
type_str_buf to be 128 bytes.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20221120051004.3605026-2-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The old behavior of bpf_map_meta_equal was that it compared timer_off
to be equal (but not spin_lock_off, because that was not allowed), and
did memcmp of kptr_off_tab.
Now, we memcmp the btf_record of two bpf_map structs, which has all
fields.
We preserve backwards compat as we kzalloc the array, so if only spin
lock and timer exist in map, we only compare offset while the rest of
unused members in the btf_field struct are zeroed out.
In case of kptr, btf and everything else is of vmlinux or module, so as
long type is same it will match, since kernel btf, module, dtor pointer
will be same across maps.
Now with list_head in the mix, things are a bit complicated. We
implicitly add a requirement that both BTFs are same, because struct
btf_field_list_head has btf and value_rec members.
We obviously shouldn't force BTFs to be equal by default, as that breaks
backwards compatibility.
Currently it is only implicitly required due to list_head matching
struct btf and value_rec member. value_rec points back into a btf_record
stashed in the map BTF (btf member of btf_field_list_head). So that
pointer and btf member has to match exactly.
Document all these subtle details so that things don't break in the
future when touching this code.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221118015614.2013203-19-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit implements the delayed release logic for bpf_list_push_front
and bpf_list_push_back.
Once a node has been added to the list, it's pointer changes to
PTR_UNTRUSTED. However, it is only released once the lock protecting the
list is unlocked. For such PTR_TO_BTF_ID | MEM_ALLOC with PTR_UNTRUSTED
set but an active ref_obj_id, it is still permitted to read them as long
as the lock is held. Writing to them is not allowed.
This allows having read access to push items we no longer own until we
release the lock guarding the list, allowing a little more flexibility
when working with these APIs.
Note that enabling write support has fairly tricky interactions with
what happens inside the critical section. Just as an example, currently,
bpf_obj_drop is not permitted, but if it were, being able to write to
the PTR_UNTRUSTED pointer while the object gets released back to the
memory allocator would violate safety properties we wish to guarantee
(i.e. not crashing the kernel). The memory could be reused for a
different type in the BPF program or even in the kernel as it gets
eventually kfree'd.
Not enabling bpf_obj_drop inside the critical section would appear to
prevent all of the above, but that is more of an artifical limitation
right now. Since the write support is tangled with how we handle
potential aliasing of nodes inside the critical section that may or may
not be part of the list anymore, it has been deferred to a future patch.
Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221118015614.2013203-18-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add a linked list API for use in BPF programs, where it expects
protection from the bpf_spin_lock in the same allocation as the
bpf_list_head. For now, only one bpf_spin_lock can be present hence that
is assumed to be the one protecting the bpf_list_head.
The following functions are added to kick things off:
// Add node to beginning of list
void bpf_list_push_front(struct bpf_list_head *head, struct bpf_list_node *node);
// Add node to end of list
void bpf_list_push_back(struct bpf_list_head *head, struct bpf_list_node *node);
// Remove node at beginning of list and return it
struct bpf_list_node *bpf_list_pop_front(struct bpf_list_head *head);
// Remove node at end of list and return it
struct bpf_list_node *bpf_list_pop_back(struct bpf_list_head *head);
The lock protecting the bpf_list_head needs to be taken for all
operations. The verifier ensures that the lock that needs to be taken is
always held, and only the correct lock is taken for these operations.
These checks are made statically by relying on the reg->id preserved for
registers pointing into regions having both bpf_spin_lock and the
objects protected by it. The comment over check_reg_allocation_locked in
this change describes the logic in detail.
Note that bpf_list_push_front and bpf_list_push_back are meant to
consume the object containing the node in the 1st argument, however that
specific mechanism is intended to not release the ref_obj_id directly
until the bpf_spin_unlock is called. In this commit, nothing is done,
but the next commit will be introducing logic to handle this case, so it
has been left as is for now.
bpf_list_pop_front and bpf_list_pop_back delete the first or last item
of the list respectively, and return pointer to the element at the
list_node offset. The user can then use container_of style macro to get
the actual entry type. The verifier however statically knows the actual
type, so the safety properties are still preserved.
With these additions, programs can now manage their own linked lists and
store their objects in them.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221118015614.2013203-17-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Pointer increment on seeing PTR_MAYBE_NULL is already protected against,
hence make an exception for PTR_TO_BTF_ID | MEM_ALLOC while still
keeping the warning for other unintended cases that might creep in.
bpf_list_pop_{front,_back} helpers planned to be introduced in next
commit will return a MEM_ALLOC register with incremented offset pointing
to bpf_list_node field. The user is supposed to then obtain the pointer
to the entry using container_of after NULL checking it. The current
restrictions trigger a warning when doing the NULL checking. Revisiting
the reason, it is meant as an assertion which seems to actually work and
catch the bad case.
Hence, under no other circumstances can reg->off be non-zero for a
register that has the PTR_MAYBE_NULL type flag set.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221118015614.2013203-16-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Introduce bpf_obj_drop, which is the kfunc used to free allocated
objects (allocated using bpf_obj_new). Pairing with bpf_obj_new, it
implicitly destructs the fields part of object automatically without
user intervention.
Just like the previous patch, btf_struct_meta that is needed to free up
the special fields is passed as a hidden argument to the kfunc.
For the user, a convenience macro hides over the kernel side kfunc which
is named bpf_obj_drop_impl.
Continuing the previous example:
void prog(void) {
struct foo *f;
f = bpf_obj_new(typeof(*f));
if (!f)
return;
bpf_obj_drop(f);
}
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221118015614.2013203-15-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Introduce type safe memory allocator bpf_obj_new for BPF programs. The
kernel side kfunc is named bpf_obj_new_impl, as passing hidden arguments
to kfuncs still requires having them in prototype, unlike BPF helpers
which always take 5 arguments and have them checked using bpf_func_proto
in verifier, ignoring unset argument types.
Introduce __ign suffix to ignore a specific kfunc argument during type
checks, then use this to introduce support for passing type metadata to
the bpf_obj_new_impl kfunc.
The user passes BTF ID of the type it wants to allocates in program BTF,
the verifier then rewrites the first argument as the size of this type,
after performing some sanity checks (to ensure it exists and it is a
struct type).
The second argument is also fixed up and passed by the verifier. This is
the btf_struct_meta for the type being allocated. It would be needed
mostly for the offset array which is required for zero initializing
special fields while leaving the rest of storage in unitialized state.
It would also be needed in the next patch to perform proper destruction
of the object's special fields.
Under the hood, bpf_obj_new will call bpf_mem_alloc and bpf_mem_free,
using the any context BPF memory allocator introduced recently. To this
end, a global instance of the BPF memory allocator is initialized on
boot to be used for this purpose. This 'bpf_global_ma' serves all
allocations for bpf_obj_new. In the future, bpf_obj_new variants will
allow specifying a custom allocator.
Note that now that bpf_obj_new can be used to allocate objects that can
be linked to BPF linked list (when future linked list helpers are
available), we need to also free the elements using bpf_mem_free.
However, since the draining of elements is done outside the
bpf_spin_lock, we need to do migrate_disable around the call since
bpf_list_head_free can be called from map free path where migration is
enabled. Otherwise, when called from BPF programs migration is already
disabled.
A convenience macro is included in the bpf_experimental.h header to hide
over the ugly details of the implementation, leading to user code
looking similar to a language level extension which allocates and
constructs fields of a user type.
struct bar {
struct bpf_list_node node;
};
struct foo {
struct bpf_spin_lock lock;
struct bpf_list_head head __contains(bar, node);
};
void prog(void) {
struct foo *f;
f = bpf_obj_new(typeof(*f));
if (!f)
return;
...
}
A key piece of this story is still missing, i.e. the free function,
which will come in the next patch.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221118015614.2013203-14-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Allow passing known constant scalars as arguments to kfuncs that do not
represent a size parameter. We use mark_chain_precision for the constant
scalar argument to mark it precise. This makes the search pruning
optimization of verifier more conservative for such kfunc calls, and
each non-distinct argument is considered unequivalent.
We will use this support to then expose a bpf_obj_new function where it
takes the local type ID of a type in program BTF, and returns a
PTR_TO_BTF_ID | MEM_ALLOC to the local type, and allows programs to
allocate their own objects.
Each type ID resolves to a distinct type with a possibly distinct size,
hence the type ID constant matters in terms of program safety and its
precision needs to be checked between old and cur states inside regsafe.
The use of mark_chain_precision enables this.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221118015614.2013203-13-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
As we continue to add more features, argument types, kfunc flags, and
different extensions to kfuncs, the code to verify the correctness of
the kfunc prototype wrt the passed in registers has become ad-hoc and
ugly to read. To make life easier, and make a very clear split between
different stages of argument processing, move all the code into
verifier.c and refactor into easier to read helpers and functions.
This also makes sharing code within the verifier easier with kfunc
argument processing. This will be more and more useful in later patches
as we are now moving to implement very core BPF helpers as kfuncs, to
keep them experimental before baking into UAPI.
Remove all kfunc related bits now from btf_check_func_arg_match, as
users have been converted away to refactored kfunc argument handling.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221118015614.2013203-12-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
There is no need to restrict users from locking bpf_spin_lock in map
values of inner maps. Each inner map lookup gets a unique reg->id
assigned to the returned PTR_TO_MAP_VALUE which will be preserved after
the NULL check. Distinct lookups into different inner map get unique
IDs, and distinct lookups into same inner map also get unique IDs.
Hence, lift the restriction by removing the check return -ENOTSUPP in
map_in_map.c. Later commits will add comprehensive test cases to ensure
that invalid cases are rejected.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221118015614.2013203-11-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Global variables reside in maps accessible using direct_value_addr
callbacks, so giving each load instruction's rewrite a unique reg->id
disallows us from holding locks which are global.
The reason for preserving reg->id as a unique value for registers that
may point to spin lock is that two separate lookups are treated as two
separate memory regions, and any possible aliasing is ignored for the
purposes of spin lock correctness.
This is not great especially for the global variable case, which are
served from maps that have max_entries == 1, i.e. they always lead to
map values pointing into the same map value.
So refactor the active_spin_lock into a 'active_lock' structure which
represents the lock identity, and instead of the reg->id, remember two
fields, a pointer and the reg->id. The pointer will store reg->map_ptr
or reg->btf. It's only necessary to distinguish for the id == 0 case of
global variables, but always setting the pointer to a non-NULL value and
using the pointer to check whether the lock is held simplifies code in
the verifier.
This is generic enough to allow it for global variables, map lookups,
and allocated objects at the same time.
Note that while whether a lock is held can be answered by just comparing
active_lock.ptr to NULL, to determine whether the register is pointing
to the same held lock requires comparing _both_ ptr and id.
Finally, as a result of this refactoring, pseudo load instructions are
not given a unique reg->id, as they are doing lookup for the same map
value (max_entries is never greater than 1).
Essentially, we consider that the tuple of (ptr, id) will always be
unique for any kind of argument to bpf_spin_{lock,unlock}.
Note that this can be extended in the future to also remember offset
used for locking, so that we can introduce multiple bpf_spin_lock fields
in the same allocation.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221118015614.2013203-10-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Allow locking a bpf_spin_lock in an allocated object, in addition to
already supported map value pointers. The handling is similar to that of
map values, by just preserving the reg->id of PTR_TO_BTF_ID | MEM_ALLOC
as well, and adjusting process_spin_lock to work with them and remember
the id in verifier state.
Refactor the existing process_spin_lock to work with PTR_TO_BTF_ID |
MEM_ALLOC in addition to PTR_TO_MAP_VALUE. We need to update the
reg_may_point_to_spin_lock which is used in mark_ptr_or_null_reg to
preserve reg->id, that will be used in env->cur_state->active_spin_lock
to remember the currently held spin lock.
Also update the comment describing bpf_spin_lock implementation details
to also talk about PTR_TO_BTF_ID | MEM_ALLOC type.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221118015614.2013203-9-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Ensure that there can be no ownership cycles among different types by
way of having owning objects that can hold some other type as their
element. For instance, a map value can only hold allocated objects, but
these are allowed to have another bpf_list_head. To prevent unbounded
recursion while freeing resources, elements of bpf_list_head in local
kptrs can never have a bpf_list_head which are part of list in a map
value. Later patches will verify this by having dedicated BTF selftests.
Also, to make runtime destruction easier, once btf_struct_metas is fully
populated, we can stash the metadata of the value type directly in the
metadata of the list_head fields, as that allows easier access to the
value type's layout to destruct it at runtime from the btf_field entry
of the list head itself.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221118015614.2013203-8-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Allow specifying bpf_spin_lock, bpf_list_head, bpf_list_node fields in a
allocated object.
Also update btf_struct_access to reject direct access to these special
fields.
A bpf_list_head allows implementing map-in-map style use cases, where an
allocated object with bpf_list_head is linked into a list in a map
value. This would require embedding a bpf_list_node, support for which
is also included. The bpf_spin_lock is used to protect the bpf_list_head
and other data.
While we strictly don't require to hold a bpf_spin_lock while touching
the bpf_list_head in such objects, as when have access to it, we have
complete ownership of the object, the locking constraint is still kept
and may be conditionally lifted in the future.
Note that the specification of such types can be done just like map
values, e.g.:
struct bar {
struct bpf_list_node node;
};
struct foo {
struct bpf_spin_lock lock;
struct bpf_list_head head __contains(bar, node);
struct bpf_list_node node;
};
struct map_value {
struct bpf_spin_lock lock;
struct bpf_list_head head __contains(foo, node);
};
To recognize such types in user BTF, we build a btf_struct_metas array
of metadata items corresponding to each BTF ID. This is done once during
the btf_parse stage to avoid having to do it each time during the
verification process's requirement to inspect the metadata.
Moreover, the computed metadata needs to be passed to some helpers in
future patches which requires allocating them and storing them in the
BTF that is pinned by the program itself, so that valid access can be
assumed to such data during program runtime.
A key thing to note is that once a btf_struct_meta is available for a
type, both the btf_record and btf_field_offs should be available. It is
critical that btf_field_offs is available in case special fields are
present, as we extensively rely on special fields being zeroed out in
map values and allocated objects in later patches. The code ensures that
by bailing out in case of errors and ensuring both are available
together. If the record is not available, the special fields won't be
recognized, so not having both is also fine (in terms of being a
verification error and not a runtime bug).
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221118015614.2013203-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Introduce support for representing pointers to objects allocated by the
BPF program, i.e. PTR_TO_BTF_ID that point to a type in program BTF.
This is indicated by the presence of MEM_ALLOC type flag in reg->type to
avoid having to check btf_is_kernel when trying to match argument types
in helpers.
Whenever walking such types, any pointers being walked will always yield
a SCALAR instead of pointer. In the future we might permit kptr inside
such allocated objects (either kernel or program allocated), and it will
then form a PTR_TO_BTF_ID of the respective type.
For now, such allocated objects will always be referenced in verifier
context, hence ref_obj_id == 0 for them is a bug. It is allowed to write
to such objects, as long fields that are special are not touched
(support for which will be added in subsequent patches). Note that once
such a pointer is marked PTR_UNTRUSTED, it is no longer allowed to write
to it.
No PROBE_MEM handling is therefore done for loads into this type unless
PTR_UNTRUSTED is part of the register type, since they can never be in
an undefined state, and their lifetime will always be valid.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221118015614.2013203-6-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Far too much code simply assumes that both btf_record and btf_field_offs
are set to valid pointers together, or both are unset. They go together
hand in hand as btf_record describes the special fields and
btf_field_offs is compact representation for runtime copying/zeroing.
It is very difficult to make this clear in the code when the only
exception to this universal invariant is inner_map_meta which is used
as reg->map_ptr in the verifier. This is simply a bug waiting to happen,
as in verifier context we cannot easily distinguish if PTR_TO_MAP_VALUE
is coming from an inner map, and if we ever end up using field_offs for
any reason in the future, we will silently ignore the special fields for
inner map case (as NULL is not an error but unset field_offs).
Hence, simply copy field_offs from inner map together with btf_record.
While at it, refactor code to unwind properly on errors with gotos.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221118015614.2013203-5-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Whenever btf_record_dup fails, we must free inner_map_meta that was
allocated before.
This fixes a memory leak (in case of errors) during inner map creation.
Fixes: aa3496accc ("bpf: Refactor kptr_off_tab into btf_record")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221118015614.2013203-4-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Since the commit being fixed, we now miss freeing btf_record for local
storage maps which will have a btf_record populated in case they have
bpf_spin_lock element.
This was missed because I made the choice of offloading the job to free
kptr_off_tab (now btf_record) to the map_free callback when adding
support for kptrs.
Revisiting the reason for this decision, there is the possibility that
the btf_record gets used inside map_free callback (e.g. in case of maps
embedding kptrs) to iterate over them and free them, hence doing it
before the map_free callback would be leaking special field memory, and
do invalid memory access. The btf_record keeps module references which
is critical to ensure the dtor call made for referenced kptr is safe to
do.
If doing it after map_free callback, the map area is already freed, so
we cannot access bpf_map structure anymore.
To fix this and prevent such lapses in future, move bpf_map_free_record
out of the map_free callback, and do it after map_free by remembering
the btf_record pointer. There is no need to access bpf_map structure in
that case, and we can avoid missing this case when support for new map
types is added for other special fields.
Since a btf_record and its btf_field_offs are used together, for
consistency delay freeing of field_offs as well. While not a problem
right now, a lot of code assumes that either both record and field_offs
are set or none at once.
Note that in case of map of maps (outer maps), inner_map_meta->record is
only used during verification, not to free fields in map value, hence we
simply keep the bpf_map_free_record call as is in bpf_map_meta_free and
never touch map->inner_map_meta in bpf_map_free_deferred.
Add a comment making note of these details.
Fixes: db55911782 ("bpf: Consolidate spin_lock, timer management into btf_record")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221118015614.2013203-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Instead of returning directly with -EOPNOTSUPP for the timer case, we
need to free the btf_record before returning to userspace.
Fixes: db55911782 ("bpf: Consolidate spin_lock, timer management into btf_record")
Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221118015614.2013203-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This is a simple mechanical transformation done by:
@@
expression E;
@@
- prandom_u32_max
+ get_random_u32_below
(E)
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Reviewed-by: SeongJae Park <sj@kernel.org> # for damon
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> # for infiniband
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> # for arm
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Currently bpf_map_do_batch() first invokes fdget(batch.map_fd) to get
the target map file, then it invokes generic_map_update_batch() to do
batch update. generic_map_update_batch() will get the target map file
by using fdget(batch.map_fd) again and pass it to bpf_map_update_value().
The problem is map file returned by the second fdget() may be NULL or a
totally different file compared by map file in bpf_map_do_batch(). The
reason is that the first fdget() only guarantees the liveness of struct
file instead of file descriptor and the file description may be released
by concurrent close() through pick_file().
It doesn't incur any problem as for now, because maps with batch update
support don't use map file in .map_fd_get_ptr() ops. But it is better to
fix the potential access of an invalid map file.
Using __bpf_map_get() again in generic_map_update_batch() can not fix
the problem, because batch.map_fd may be closed and reopened, and the
returned map file may be different with map file got in
bpf_map_do_batch(), so just passing the map file directly to
.map_update_batch() in bpf_map_do_batch().
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20221116075059.1551277-1-houtao@huaweicloud.com
Propagate nullness information for branches of register to register
equality compare instructions. The following rules are used:
- suppose register A maybe null
- suppose register B is not null
- for JNE A, B, ... - A is not null in the false branch
- for JEQ A, B, ... - A is not null in the true branch
E.g. for program like below:
r6 = skb->sk;
r7 = sk_fullsock(r6);
r0 = sk_fullsock(r6);
if (r0 == 0) return 0; (a)
if (r0 != r7) return 0; (b)
*r7->type; (c)
return 0;
It is safe to dereference r7 at point (c), because of (a) and (b).
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221115224859.2452988-2-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
For queueing packets in XDP we want to add a new redirect map type with
support for 64-bit indexes. To prepare fore this, expand the width of the
'key' argument to the bpf_redirect_map() helper. Since BPF registers are
always 64-bit, this should be safe to do after the fact.
Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/r/20221108140601.149971-3-toke@redhat.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Instead of having to pass multiple arguments that describe the register,
pass the bpf_reg_state into the btf_struct_access callback. Currently,
all call sites simply reuse the btf and btf_id of the reg they want to
check the access of. The only exception to this pattern is the callsite
in check_ptr_to_map_access, hence for that case create a dummy reg to
simulate PTR_TO_BTF_ID access.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221114191547.1694267-8-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently, verifier uses MEM_ALLOC type tag to specially tag memory
returned from bpf_ringbuf_reserve helper. However, this is currently
only used for this purpose and there is an implicit assumption that it
only refers to ringbuf memory (e.g. the check for ARG_PTR_TO_ALLOC_MEM
in check_func_arg_reg_off).
Hence, rename MEM_ALLOC to MEM_RINGBUF to indicate this special
relationship and instead open the use of MEM_ALLOC for more generic
allocations made for user types.
Also, since ARG_PTR_TO_ALLOC_MEM_OR_NULL is unused, simply drop it.
Finally, update selftests using 'alloc_' verifier string to 'ringbuf_'.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221114191547.1694267-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently, the verifier has two return types, RET_PTR_TO_ALLOC_MEM, and
RET_PTR_TO_ALLOC_MEM_OR_NULL, however the former is confusingly named to
imply that it carries MEM_ALLOC, while only the latter does. This causes
confusion during code review leading to conclusions like that the return
value of RET_PTR_TO_DYNPTR_MEM_OR_NULL (which is RET_PTR_TO_ALLOC_MEM |
PTR_MAYBE_NULL) may be consumable by bpf_ringbuf_{submit,commit}.
Rename it to make it clear MEM_ALLOC needs to be tacked on top of
RET_PTR_TO_MEM.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221114191547.1694267-6-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add the support on the map side to parse, recognize, verify, and build
metadata table for a new special field of the type struct bpf_list_head.
To parameterize the bpf_list_head for a certain value type and the
list_node member it will accept in that value type, we use BTF
declaration tags.
The definition of bpf_list_head in a map value will be done as follows:
struct foo {
struct bpf_list_node node;
int data;
};
struct map_value {
struct bpf_list_head head __contains(foo, node);
};
Then, the bpf_list_head only allows adding to the list 'head' using the
bpf_list_node 'node' for the type struct foo.
The 'contains' annotation is a BTF declaration tag composed of four
parts, "contains:name:node" where the name is then used to look up the
type in the map BTF, with its kind hardcoded to BTF_KIND_STRUCT during
the lookup. The node defines name of the member in this type that has
the type struct bpf_list_node, which is actually used for linking into
the linked list. For now, 'kind' part is hardcoded as struct.
This allows building intrusive linked lists in BPF, using container_of
to obtain pointer to entry, while being completely type safe from the
perspective of the verifier. The verifier knows exactly the type of the
nodes, and knows that list helpers return that type at some fixed offset
where the bpf_list_node member used for this list exists. The verifier
also uses this information to disallow adding types that are not
accepted by a certain list.
For now, no elements can be added to such lists. Support for that is
coming in future patches, hence draining and freeing items is done with
a TODO that will be resolved in a future patch.
Note that the bpf_list_head_free function moves the list out to a local
variable under the lock and releases it, doing the actual draining of
the list items outside the lock. While this helps with not holding the
lock for too long pessimizing other concurrent list operations, it is
also necessary for deadlock prevention: unless every function called in
the critical section would be notrace, a fentry/fexit program could
attach and call bpf_map_update_elem again on the map, leading to the
same lock being acquired if the key matches and lead to a deadlock.
While this requires some special effort on part of the BPF programmer to
trigger and is highly unlikely to occur in practice, it is always better
if we can avoid such a condition.
While notrace would prevent this, doing the draining outside the lock
has advantages of its own, hence it is used to also fix the deadlock
related problem.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221114191547.1694267-5-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In f71b2f6417 ("bpf: Refactor map->off_arr handling"), map->off_arr
was refactored to be btf_field_offs. The number of field offsets is
equal to maximum possible fields limited by BTF_FIELDS_MAX. Hence, reuse
BTF_FIELDS_MAX as spin_lock and timer no longer are to be handled
specially for offset sorting, fix the comment, and remove incorrect
WARN_ON as its rec->cnt can never exceed this value. The reason to keep
separate constant was the it was always more 2 more than total kptrs.
This is no longer the case.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221114191547.1694267-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Andrii Nakryiko says:
====================
bpf-next 2022-11-11
We've added 49 non-merge commits during the last 9 day(s) which contain
a total of 68 files changed, 3592 insertions(+), 1371 deletions(-).
The main changes are:
1) Veristat tool improvements to support custom filtering, sorting, and replay
of results, from Andrii Nakryiko.
2) BPF verifier precision tracking fixes and improvements,
from Andrii Nakryiko.
3) Lots of new BPF documentation for various BPF maps, from Dave Tucker,
Donald Hunter, Maryam Tahhan, Bagas Sanjaya.
4) BTF dedup improvements and libbpf's hashmap interface clean ups, from
Eduard Zingerman.
5) Fix veth driver panic if XDP program is attached before veth_open, from
John Fastabend.
6) BPF verifier clean ups and fixes in preparation for follow up features,
from Kumar Kartikeya Dwivedi.
7) Add access to hwtstamp field from BPF sockops programs,
from Martin KaFai Lau.
8) Various fixes for BPF selftests and samples, from Artem Savkov,
Domenico Cerasuolo, Kang Minchul, Rong Tao, Yang Jihong.
9) Fix redirection to tunneling device logic, preventing skb->len == 0, from
Stanislav Fomichev.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (49 commits)
selftests/bpf: fix veristat's singular file-or-prog filter
selftests/bpf: Test skops->skb_hwtstamp
selftests/bpf: Fix incorrect ASSERT in the tcp_hdr_options test
bpf: Add hwtstamp field for the sockops prog
selftests/bpf: Fix xdp_synproxy compilation failure in 32-bit arch
bpf, docs: Document BPF_MAP_TYPE_ARRAY
docs/bpf: Document BPF map types QUEUE and STACK
docs/bpf: Document BPF ARRAY_OF_MAPS and HASH_OF_MAPS
docs/bpf: Document BPF_MAP_TYPE_CPUMAP map
docs/bpf: Document BPF_MAP_TYPE_LPM_TRIE map
libbpf: Hashmap.h update to fix build issues using LLVM14
bpf: veth driver panics when xdp prog attached before veth_open
selftests: Fix test group SKIPPED result
selftests/bpf: Tests for btf_dedup_resolve_fwds
libbpf: Resolve unambigous forward declarations
libbpf: Hashmap interface update to allow both long and void* keys/values
samples/bpf: Fix sockex3 error: Missing BPF prog type
selftests/bpf: Fix u32 variable compared with less than zero
Documentation: bpf: Escape underscore in BPF type name prefix
selftests/bpf: Use consistent build-id type for liburandom_read.so
...
====================
Link: https://lore.kernel.org/r/20221111233733.1088228-1-andrii@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
pcpu_freelist_populate() initializes nr_elems / num_possible_cpus() + 1
free nodes for some CPUs, and then possibly one CPU with fewer nodes,
followed by remaining cpus with 0 nodes. For example, when nr_elems == 256
and num_possible_cpus() == 32, CPU 0~27 each gets 9 free nodes, CPU 28 gets
4 free nodes, CPU 29~31 get 0 free nodes, while in fact each CPU should get
8 nodes equally.
This patch initializes nr_elems / num_possible_cpus() free nodes for each
CPU firstly, then allocates the remaining free nodes by one for each CPU
until no free nodes left.
Fixes: e19494edab ("bpf: introduce percpu_freelist")
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20221110122128.105214-1-xukuohai@huawei.com
Add documentation for BPF_MAP_TYPE_CPUMAP including
kernel version introduced, usage and examples.
Co-developed-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Maryam Tahhan <mtahhan@redhat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20221107165207.2682075-2-mtahhan@redhat.com
kmemleak reports this issue:
unreferenced object 0xffff88817139d000 (size 2048):
comm "test_progs", pid 33246, jiffies 4307381979 (age 45851.820s)
hex dump (first 32 bytes):
01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<0000000045f075f0>] kmalloc_trace+0x27/0xa0
[<0000000098b7c90a>] __check_func_call+0x316/0x1230
[<00000000b4c3c403>] check_helper_call+0x172e/0x4700
[<00000000aa3875b7>] do_check+0x21d8/0x45e0
[<000000001147357b>] do_check_common+0x767/0xaf0
[<00000000b5a595b4>] bpf_check+0x43e3/0x5bc0
[<0000000011e391b1>] bpf_prog_load+0xf26/0x1940
[<0000000007f765c0>] __sys_bpf+0xd2c/0x3650
[<00000000839815d6>] __x64_sys_bpf+0x75/0xc0
[<00000000946ee250>] do_syscall_64+0x3b/0x90
[<0000000000506b7f>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
The root case here is: In function prepare_func_exit(), the callee is
not released in the abnormal scenario after "state->curframe--;". To
fix, move "state->curframe--;" to the very bottom of the function,
right when we free callee and reset frame[] pointer to NULL, as Andrii
suggested.
In addition, function __check_func_call() has a similar problem. In
the abnormal scenario before "state->curframe++;", the callee also
should be released by free_func_state().
Fixes: 69c087ba62 ("bpf: Add bpf_for_each_map_elem() helper")
Fixes: fd978bf7fd ("bpf: Add reference tracking to verifier")
Signed-off-by: Wang Yufen <wangyufen@huawei.com>
Link: https://lore.kernel.org/r/1667884291-15666-1-git-send-email-wangyufen@huawei.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
When building with clang:
kernel/bpf/dispatcher.c:126:33: error: pointer type mismatch ('void *' and 'unsigned int (*)(const void *, const struct bpf_insn *, bpf_func_t)' (aka 'unsigned int (*)(const void *, const struct bpf_insn *, unsigned int (*)(const void *, const struct bpf_insn *))')) [-Werror,-Wpointer-type-mismatch]
__BPF_DISPATCHER_UPDATE(d, new ?: &bpf_dispatcher_nop_func);
~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/bpf.h:1045:54: note: expanded from macro '__BPF_DISPATCHER_UPDATE'
__static_call_update((_d)->sc_key, (_d)->sc_tramp, (_new))
^~~~
1 error generated.
The warning is pointing out that the type of new ('void *') and
&bpf_dispatcher_nop_func are not compatible, which could have side
effects coming out of a conditional operator due to promotion rules.
Add the explicit cast to 'void *' to make it clear that this is
expected, as __BPF_DISPATCHER_UPDATE() expands to a call to
__static_call_update(), which expects a 'void *' as its final argument.
Fixes: c86df29d11 ("bpf: Convert BPF_DISPATCHER to use static_call() (not ftrace)")
Link: https://github.com/ClangBuiltLinux/linux/issues/1755
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: "kernelci.org bot" <bot@kernelci.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Björn Töpel <bjorn@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221107170711.42409-1-nathan@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
The dispatcher function is currently abusing the ftrace __fentry__
call location for its own purposes -- this obviously gives trouble
when the dispatcher and ftrace are both in use.
A previous solution tried using __attribute__((patchable_function_entry()))
which works, except it is GCC-8+ only, breaking the build on the
earlier still supported compilers. Instead use static_call() -- which
has its own annotations and does not conflict with ftrace -- to
rewrite the dispatch function.
By using: return static_call()(ctx, insni, bpf_func) you get a perfect
forwarding tail call as function body (iow a single jmp instruction).
By having the default static_call() target be bpf_dispatcher_nop_func()
it retains the default behaviour (an indirect call to the argument
function). Only once a dispatcher program is attached is the target
rewritten to directly call the JIT'ed image.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Björn Töpel <bjorn@kernel.org>
Tested-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Björn Töpel <bjorn@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lkml.kernel.org/r/Y1/oBlK0yFk5c/Im@hirez.programming.kicks-ass.net
Link: https://lore.kernel.org/bpf/20221103120647.796772565@infradead.org
Because __attribute__((patchable_function_entry)) is only available
since GCC-8 this solution fails to build on the minimum required GCC
version.
Undo these changes so we might try again -- without cluttering up the
patches with too many changes.
This is an almost complete revert of:
dbe69b2998 ("bpf: Fix dispatcher patchable function entry to 5 bytes nop")
ceea991a01 ("bpf: Move bpf_dispatcher function out of ftrace locations")
(notably the arch/x86/Kconfig hunk is kept).
Reported-by: David Laight <David.Laight@aculab.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Björn Töpel <bjorn@kernel.org>
Tested-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Björn Töpel <bjorn@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lkml.kernel.org/r/439d8dc735bb4858875377df67f1b29a@AcuMS.aculab.com
Link: https://lore.kernel.org/bpf/20221103120647.728830733@infradead.org
Exploit the property of about-to-be-checkpointed state to be able to
forget all precise markings up to that point even more aggressively. We
now clear all potentially inherited precise markings right before
checkpointing and branching off into child state. If any of children
states require precise knowledge of any SCALAR register, those will be
propagated backwards later on before this state is finalized, preserving
correctness.
There is a single selftests BPF program change, but tremendous one: 25x
reduction in number of verified instructions and states in
trace_virtqueue_add_sgs.
Cilium results are more modest, but happen across wider range of programs.
SELFTESTS RESULTS
=================
$ ./veristat -C -e file,prog,insns,states ~/imprecise-early-results.csv ~/imprecise-aggressive-results.csv | grep -v '+0'
File Program Total insns (A) Total insns (B) Total insns (DIFF) Total states (A) Total states (B) Total states (DIFF)
------------------- ----------------------- --------------- --------------- ------------------ ---------------- ---------------- -------------------
loop6.bpf.linked1.o trace_virtqueue_add_sgs 398057 15114 -382943 (-96.20%) 8717 336 -8381 (-96.15%)
------------------- ----------------------- --------------- --------------- ------------------ ---------------- ---------------- -------------------
CILIUM RESULTS
==============
$ ./veristat -C -e file,prog,insns,states ~/imprecise-early-results-cilium.csv ~/imprecise-aggressive-results-cilium.csv | grep -v '+0'
File Program Total insns (A) Total insns (B) Total insns (DIFF) Total states (A) Total states (B) Total states (DIFF)
------------- -------------------------------- --------------- --------------- ------------------ ---------------- ---------------- -------------------
bpf_host.o tail_handle_nat_fwd_ipv4 23426 23221 -205 (-0.88%) 1537 1515 -22 (-1.43%)
bpf_host.o tail_handle_nat_fwd_ipv6 13009 12904 -105 (-0.81%) 719 708 -11 (-1.53%)
bpf_host.o tail_nodeport_nat_ingress_ipv6 5261 5196 -65 (-1.24%) 247 243 -4 (-1.62%)
bpf_host.o tail_nodeport_nat_ipv6_egress 3446 3406 -40 (-1.16%) 203 198 -5 (-2.46%)
bpf_lxc.o tail_handle_nat_fwd_ipv4 23426 23221 -205 (-0.88%) 1537 1515 -22 (-1.43%)
bpf_lxc.o tail_handle_nat_fwd_ipv6 13009 12904 -105 (-0.81%) 719 708 -11 (-1.53%)
bpf_lxc.o tail_ipv4_ct_egress 5074 4897 -177 (-3.49%) 255 248 -7 (-2.75%)
bpf_lxc.o tail_ipv4_ct_ingress 5100 4923 -177 (-3.47%) 255 248 -7 (-2.75%)
bpf_lxc.o tail_ipv4_ct_ingress_policy_only 5100 4923 -177 (-3.47%) 255 248 -7 (-2.75%)
bpf_lxc.o tail_ipv6_ct_egress 4558 4536 -22 (-0.48%) 188 187 -1 (-0.53%)
bpf_lxc.o tail_ipv6_ct_ingress 4578 4556 -22 (-0.48%) 188 187 -1 (-0.53%)
bpf_lxc.o tail_ipv6_ct_ingress_policy_only 4578 4556 -22 (-0.48%) 188 187 -1 (-0.53%)
bpf_lxc.o tail_nodeport_nat_ingress_ipv6 5261 5196 -65 (-1.24%) 247 243 -4 (-1.62%)
bpf_overlay.o tail_nodeport_nat_ingress_ipv6 5261 5196 -65 (-1.24%) 247 243 -4 (-1.62%)
bpf_overlay.o tail_nodeport_nat_ipv6_egress 3482 3442 -40 (-1.15%) 204 201 -3 (-1.47%)
bpf_xdp.o tail_nodeport_nat_egress_ipv4 17200 15619 -1581 (-9.19%) 1111 1010 -101 (-9.09%)
------------- -------------------------------- --------------- --------------- ------------------ ---------------- ---------------- -------------------
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221104163649.121784-6-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Setting reg->precise to true in current state is not necessary from
correctness standpoint, but it does pessimise the whole precision (or
rather "imprecision", because that's what we want to keep as much as
possible) tracking. Why is somewhat subtle and my best attempt to
explain this is recorded in an extensive comment for __mark_chain_precise()
function. Some more careful thinking and code reading is probably required
still to grok this completely, unfortunately. Whiteboarding and a bunch
of extra handwaiving in person would be even more helpful, but is deemed
impractical in Git commit.
Next patch pushes this imprecision property even further, building on top of
the insights described in this patch.
End results are pretty nice, we get reduction in number of total instructions
and states verified due to a better states reuse, as some of the states are now
more generic and permissive due to less unnecessary precise=true requirements.
SELFTESTS RESULTS
=================
$ ./veristat -C -e file,prog,insns,states ~/subprog-precise-results.csv ~/imprecise-early-results.csv | grep -v '+0'
File Program Total insns (A) Total insns (B) Total insns (DIFF) Total states (A) Total states (B) Total states (DIFF)
--------------------------------------- ---------------------- --------------- --------------- ------------------ ---------------- ---------------- -------------------
bpf_iter_ksym.bpf.linked1.o dump_ksym 347 285 -62 (-17.87%) 20 19 -1 (-5.00%)
pyperf600_bpf_loop.bpf.linked1.o on_event 3678 3736 +58 (+1.58%) 276 285 +9 (+3.26%)
setget_sockopt.bpf.linked1.o skops_sockopt 4038 3947 -91 (-2.25%) 347 343 -4 (-1.15%)
test_l4lb.bpf.linked1.o balancer_ingress 4559 2611 -1948 (-42.73%) 118 105 -13 (-11.02%)
test_l4lb_noinline.bpf.linked1.o balancer_ingress 6279 6268 -11 (-0.18%) 237 236 -1 (-0.42%)
test_misc_tcp_hdr_options.bpf.linked1.o misc_estab 1307 1303 -4 (-0.31%) 100 99 -1 (-1.00%)
test_sk_lookup.bpf.linked1.o ctx_narrow_access 456 447 -9 (-1.97%) 39 38 -1 (-2.56%)
test_sysctl_loop1.bpf.linked1.o sysctl_tcp_mem 1389 1384 -5 (-0.36%) 26 25 -1 (-3.85%)
test_tc_dtime.bpf.linked1.o egress_fwdns_prio101 518 485 -33 (-6.37%) 51 46 -5 (-9.80%)
test_tc_dtime.bpf.linked1.o egress_host 519 468 -51 (-9.83%) 50 44 -6 (-12.00%)
test_tc_dtime.bpf.linked1.o ingress_fwdns_prio101 842 1000 +158 (+18.76%) 73 88 +15 (+20.55%)
xdp_synproxy_kern.bpf.linked1.o syncookie_tc 405757 373173 -32584 (-8.03%) 25735 22882 -2853 (-11.09%)
xdp_synproxy_kern.bpf.linked1.o syncookie_xdp 479055 371590 -107465 (-22.43%) 29145 22207 -6938 (-23.81%)
--------------------------------------- ---------------------- --------------- --------------- ------------------ ---------------- ---------------- -------------------
Slight regression in test_tc_dtime.bpf.linked1.o/ingress_fwdns_prio101
is left for a follow up, there might be some more precision-related bugs
in existing BPF verifier logic.
CILIUM RESULTS
==============
$ ./veristat -C -e file,prog,insns,states ~/subprog-precise-results-cilium.csv ~/imprecise-early-results-cilium.csv | grep -v '+0'
File Program Total insns (A) Total insns (B) Total insns (DIFF) Total states (A) Total states (B) Total states (DIFF)
------------- ------------------------------ --------------- --------------- ------------------ ---------------- ---------------- -------------------
bpf_host.o cil_from_host 762 556 -206 (-27.03%) 43 37 -6 (-13.95%)
bpf_host.o tail_handle_nat_fwd_ipv4 23541 23426 -115 (-0.49%) 1538 1537 -1 (-0.07%)
bpf_host.o tail_nodeport_nat_egress_ipv4 33592 33566 -26 (-0.08%) 2163 2161 -2 (-0.09%)
bpf_lxc.o tail_handle_nat_fwd_ipv4 23541 23426 -115 (-0.49%) 1538 1537 -1 (-0.07%)
bpf_overlay.o tail_nodeport_nat_egress_ipv4 33581 33543 -38 (-0.11%) 2160 2157 -3 (-0.14%)
bpf_xdp.o tail_handle_nat_fwd_ipv4 21659 20920 -739 (-3.41%) 1440 1376 -64 (-4.44%)
bpf_xdp.o tail_handle_nat_fwd_ipv6 17084 17039 -45 (-0.26%) 907 905 -2 (-0.22%)
bpf_xdp.o tail_lb_ipv4 73442 73430 -12 (-0.02%) 4370 4369 -1 (-0.02%)
bpf_xdp.o tail_lb_ipv6 152114 151895 -219 (-0.14%) 6493 6479 -14 (-0.22%)
bpf_xdp.o tail_nodeport_nat_egress_ipv4 17377 17200 -177 (-1.02%) 1125 1111 -14 (-1.24%)
bpf_xdp.o tail_nodeport_nat_ingress_ipv6 6405 6397 -8 (-0.12%) 309 308 -1 (-0.32%)
bpf_xdp.o tail_rev_nodeport_lb4 7126 6934 -192 (-2.69%) 414 402 -12 (-2.90%)
bpf_xdp.o tail_rev_nodeport_lb6 18059 17905 -154 (-0.85%) 1105 1096 -9 (-0.81%)
------------- ------------------------------ --------------- --------------- ------------------ ---------------- ---------------- -------------------
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221104163649.121784-5-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Stop forcing precise=true for SCALAR registers when BPF program has any
subprograms. Current restriction means that any BPF program, as soon as
it uses subprograms, will end up not getting any of the precision
tracking benefits in reduction of number of verified states.
This patch keeps the fallback mark_all_scalars_precise() behavior if
precise marking has to cross function frames. E.g., if subprogram
requires R1 (first input arg) to be marked precise, ideally we'd need to
backtrack to the parent function and keep marking R1 and its
dependencies as precise. But right now we give up and force all the
SCALARs in any of the current and parent states to be forced to
precise=true. We can lift that restriction in the future.
But this patch fixes two issues identified when trying to enable
precision tracking for subprogs.
First, prevent "escaping" from top-most state in a global subprog. While
with entry-level BPF program we never end up requesting precision for
R1-R5 registers, because R2-R5 are not initialized (and so not readable
in correct BPF program), and R1 is PTR_TO_CTX, not SCALAR, and so is
implicitly precise. With global subprogs, though, it's different, as
global subprog a) can have up to 5 SCALAR input arguments, which might
get marked as precise=true and b) it is validated in isolation from its
main entry BPF program. b) means that we can end up exhausting parent
state chain and still not mark all registers in reg_mask as precise,
which would lead to verifier bug warning.
To handle that, we need to consider two cases. First, if the very first
state is not immediately "checkpointed" (i.e., stored in state lookup
hashtable), it will get correct first_insn_idx and last_insn_idx
instruction set during state checkpointing. As such, this case is
already handled and __mark_chain_precision() already handles that by
just doing nothing when we reach to the very first parent state.
st->parent will be NULL and we'll just stop. Perhaps some extra check
for reg_mask and stack_mask is due here, but this patch doesn't address
that issue.
More problematic second case is when global function's initial state is
immediately checkpointed before we manage to process the very first
instruction. This is happening because when there is a call to global
subprog from the main program the very first subprog's instruction is
marked as pruning point, so before we manage to process first
instruction we have to check and checkpoint state. This patch adds
a special handling for such "empty" state, which is identified by having
st->last_insn_idx set to -1. In such case, we check that we are indeed
validating global subprog, and with some sanity checking we mark input
args as precise if requested.
Note that we also initialize state->first_insn_idx with correct start
insn_idx offset. For main program zero is correct value, but for any
subprog it's quite confusing to not have first_insn_idx set. This
doesn't have any functional impact, but helps with debugging and state
printing. We also explicitly initialize state->last_insns_idx instead of
relying on is_state_visited() to do this with env->prev_insns_idx, which
will be -1 on the very first instruction. This concludes necessary
changes to handle specifically global subprog's precision tracking.
Second identified problem was missed handling of BPF helper functions
that call into subprogs (e.g., bpf_loop and few others). From precision
tracking and backtracking logic's standpoint those are effectively calls
into subprogs and should be called as BPF_PSEUDO_CALL calls.
This patch takes the least intrusive way and just checks against a short
list of current BPF helpers that do call subprogs, encapsulated in
is_callback_calling_function() function. But to prevent accidentally
forgetting to add new BPF helpers to this "list", we also do a sanity
check in __check_func_call, which has to be called for each such special
BPF helper, to validate that BPF helper is indeed recognized as
callback-calling one. This should catch any missed checks in the future.
Adding some special flags to be added in function proto definitions
seemed like an overkill in this case.
With the above changes, it's possible to remove forceful setting of
reg->precise to true in __mark_reg_unknown, which turns on precision
tracking both inside subprogs and entry progs that have subprogs. No
warnings or errors were detected across all the selftests, but also when
validating with veristat against internal Meta BPF objects and Cilium
objects. Further, in some BPF programs there are noticeable reduction in
number of states and instructions validated due to more effective
precision tracking, especially benefiting syncookie test.
$ ./veristat -C -e file,prog,insns,states ~/baseline-results.csv ~/subprog-precise-results.csv | grep -v '+0'
File Program Total insns (A) Total insns (B) Total insns (DIFF) Total states (A) Total states (B) Total states (DIFF)
---------------------------------------- -------------------------- --------------- --------------- ------------------ ---------------- ---------------- -------------------
pyperf600_bpf_loop.bpf.linked1.o on_event 3966 3678 -288 (-7.26%) 306 276 -30 (-9.80%)
pyperf_global.bpf.linked1.o on_event 7563 7530 -33 (-0.44%) 520 517 -3 (-0.58%)
pyperf_subprogs.bpf.linked1.o on_event 36358 36934 +576 (+1.58%) 2499 2531 +32 (+1.28%)
setget_sockopt.bpf.linked1.o skops_sockopt 3965 4038 +73 (+1.84%) 343 347 +4 (+1.17%)
test_cls_redirect_subprogs.bpf.linked1.o cls_redirect 64965 64901 -64 (-0.10%) 4619 4612 -7 (-0.15%)
test_misc_tcp_hdr_options.bpf.linked1.o misc_estab 1491 1307 -184 (-12.34%) 110 100 -10 (-9.09%)
test_pkt_access.bpf.linked1.o test_pkt_access 354 349 -5 (-1.41%) 25 24 -1 (-4.00%)
test_sock_fields.bpf.linked1.o egress_read_sock_fields 435 375 -60 (-13.79%) 22 20 -2 (-9.09%)
test_sysctl_loop2.bpf.linked1.o sysctl_tcp_mem 1508 1501 -7 (-0.46%) 29 28 -1 (-3.45%)
test_tc_dtime.bpf.linked1.o egress_fwdns_prio100 468 435 -33 (-7.05%) 45 41 -4 (-8.89%)
test_tc_dtime.bpf.linked1.o ingress_fwdns_prio100 398 408 +10 (+2.51%) 42 39 -3 (-7.14%)
test_tc_dtime.bpf.linked1.o ingress_fwdns_prio101 1096 842 -254 (-23.18%) 97 73 -24 (-24.74%)
test_tcp_hdr_options.bpf.linked1.o estab 2758 2408 -350 (-12.69%) 208 181 -27 (-12.98%)
test_urandom_usdt.bpf.linked1.o urand_read_with_sema 466 448 -18 (-3.86%) 31 28 -3 (-9.68%)
test_urandom_usdt.bpf.linked1.o urand_read_without_sema 466 448 -18 (-3.86%) 31 28 -3 (-9.68%)
test_urandom_usdt.bpf.linked1.o urandlib_read_with_sema 466 448 -18 (-3.86%) 31 28 -3 (-9.68%)
test_urandom_usdt.bpf.linked1.o urandlib_read_without_sema 466 448 -18 (-3.86%) 31 28 -3 (-9.68%)
test_xdp_noinline.bpf.linked1.o balancer_ingress_v6 4302 4294 -8 (-0.19%) 257 256 -1 (-0.39%)
xdp_synproxy_kern.bpf.linked1.o syncookie_tc 583722 405757 -177965 (-30.49%) 35846 25735 -10111 (-28.21%)
xdp_synproxy_kern.bpf.linked1.o syncookie_xdp 609123 479055 -130068 (-21.35%) 35452 29145 -6307 (-17.79%)
---------------------------------------- -------------------------- --------------- --------------- ------------------ ---------------- ---------------- -------------------
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221104163649.121784-4-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When equivalent completed state is found and it has additional precision
restrictions, BPF verifier propagates precision to
currently-being-verified state chain (i.e., including parent states) so
that if some of the states in the chain are not yet completed, necessary
precision restrictions are enforced.
Unfortunately, right now this happens only for the last frame (deepest
active subprogram's frame), not all the frames. This can lead to
incorrect matching of states due to missing precision marker. Currently
this doesn't seem possible as BPF verifier forces everything to precise
when validated BPF program has any subprograms. But with the next patch
lifting this restriction, this becomes problematic.
In fact, without this fix, we'll start getting failure in one of the
existing test_verifier test cases:
#906/p precise: cross frame pruning FAIL
Unexpected success to load!
verification time 48 usec
stack depth 0+0
processed 26 insns (limit 1000000) max_states_per_insn 3 total_states 17 peak_states 17 mark_read 8
This patch adds precision propagation across all frames.
Fixes: a3ce685dd0 ("bpf: fix precision tracking")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221104163649.121784-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When processing ALU/ALU64 operations (apart from BPF_MOV, which is
handled correctly already; and BPF_NEG and BPF_END are special and don't
have source register), if destination register is already marked
precise, this causes problem with potentially missing precision tracking
for the source register. E.g., when we have r1 >>= r5 and r1 is marked
precise, but r5 isn't, this will lead to r5 staying as imprecise. This
is due to the precision backtracking logic stopping early when it sees
r1 is already marked precise. If r1 wasn't precise, we'd keep
backtracking and would add r5 to the set of registers that need to be
marked precise. So there is a discrepancy here which can lead to invalid
and incompatible states matched due to lack of precision marking on r5.
If r1 wasn't precise, precision backtracking would correctly mark both
r1 and r5 as precise.
This is simple to fix, though. During the forward instruction simulation
pass, for arithmetic operations of `scalar <op>= scalar` form (where
<op> is ALU or ALU64 operations), if destination register is already
precise, mark source register as precise. This applies only when both
involved registers are SCALARs. `ptr += scalar` and `scalar += ptr`
cases are already handled correctly.
This does have (negative) effect on some selftest programs and few
Cilium programs. ~/baseline-tmp-results.csv are veristat results with
this patch, while ~/baseline-results.csv is without it. See post
scriptum for instructions on how to make Cilium programs testable with
veristat. Correctness has a price.
$ ./veristat -C -e file,prog,insns,states ~/baseline-results.csv ~/baseline-tmp-results.csv | grep -v '+0'
File Program Total insns (A) Total insns (B) Total insns (DIFF) Total states (A) Total states (B) Total states (DIFF)
----------------------- -------------------- --------------- --------------- ------------------ ---------------- ---------------- -------------------
bpf_cubic.bpf.linked1.o bpf_cubic_cong_avoid 997 1700 +703 (+70.51%) 62 90 +28 (+45.16%)
test_l4lb.bpf.linked1.o balancer_ingress 4559 5469 +910 (+19.96%) 118 126 +8 (+6.78%)
----------------------- -------------------- --------------- --------------- ------------------ ---------------- ---------------- -------------------
$ ./veristat -C -e file,prog,verdict,insns,states ~/baseline-results-cilium.csv ~/baseline-tmp-results-cilium.csv | grep -v '+0'
File Program Total insns (A) Total insns (B) Total insns (DIFF) Total states (A) Total states (B) Total states (DIFF)
------------- ------------------------------ --------------- --------------- ------------------ ---------------- ---------------- -------------------
bpf_host.o tail_nodeport_nat_ingress_ipv6 4448 5261 +813 (+18.28%) 234 247 +13 (+5.56%)
bpf_host.o tail_nodeport_nat_ipv6_egress 3396 3446 +50 (+1.47%) 201 203 +2 (+1.00%)
bpf_lxc.o tail_nodeport_nat_ingress_ipv6 4448 5261 +813 (+18.28%) 234 247 +13 (+5.56%)
bpf_overlay.o tail_nodeport_nat_ingress_ipv6 4448 5261 +813 (+18.28%) 234 247 +13 (+5.56%)
bpf_xdp.o tail_lb_ipv4 71736 73442 +1706 (+2.38%) 4295 4370 +75 (+1.75%)
------------- ------------------------------ --------------- --------------- ------------------ ---------------- ---------------- -------------------
P.S. To make Cilium ([0]) programs libbpf-compatible and thus
veristat-loadable, apply changes from topmost commit in [1], which does
minimal changes to Cilium source code, mostly around SEC() annotations
and BPF map definitions.
[0] https://github.com/cilium/cilium/
[1] https://github.com/anakryiko/cilium/commits/libbpf-friendliness
Fixes: b5dc0163d8 ("bpf: precise scalar_value tracking")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221104163649.121784-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Refactor map->off_arr handling into generic functions that can work on
their own without hardcoding map specific code. The btf_fields_offs
structure is now returned from btf_parse_field_offs, which can be reused
later for types in program BTF.
All functions like copy_map_value, zero_map_value call generic
underlying functions so that they can also be reused later for copying
to values allocated in programs which encode specific fields.
Later, some helper functions will also require access to this
btf_field_offs structure to be able to skip over special fields at
runtime.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221103191013.1236066-9-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Now that kptr_off_tab has been refactored into btf_record, and can hold
more than one specific field type, accomodate bpf_spin_lock and
bpf_timer as well.
While they don't require any more metadata than offset, having all
special fields in one place allows us to share the same code for
allocated user defined types and handle both map values and these
allocated objects in a similar fashion.
As an optimization, we still keep spin_lock_off and timer_off offsets in
the btf_record structure, just to avoid having to find the btf_field
struct each time their offset is needed. This is mostly needed to
manipulate such objects in a map value at runtime. It's ok to hardcode
just one offset as more than one field is disallowed.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221103191013.1236066-8-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
To prepare the BPF verifier to handle special fields in both map values
and program allocated types coming from program BTF, we need to refactor
the kptr_off_tab handling code into something more generic and reusable
across both cases to avoid code duplication.
Later patches also require passing this data to helpers at runtime, so
that they can work on user defined types, initialize them, destruct
them, etc.
The main observation is that both map values and such allocated types
point to a type in program BTF, hence they can be handled similarly. We
can prepare a field metadata table for both cases and store them in
struct bpf_map or struct btf depending on the use case.
Hence, refactor the code into generic btf_record and btf_field member
structs. The btf_record represents the fields of a specific btf_type in
user BTF. The cnt indicates the number of special fields we successfully
recognized, and field_mask is a bitmask of fields that were found, to
enable quick determination of availability of a certain field.
Subsequently, refactor the rest of the code to work with these generic
types, remove assumptions about kptr and kptr_off_tab, rename variables
to more meaningful names, etc.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221103191013.1236066-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
It is not scalable to maintain a list of types that can have non-zero
ref_obj_id. It is never set for scalars anyway, so just remove the
conditional on register types and print it whenever it is non-zero.
Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20221103191013.1236066-6-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
For the case where allow_ptr_leaks is false, code is checking whether
slot type is STACK_INVALID and STACK_SPILL and rejecting other cases.
This is a consequence of incorrectly checking for register type instead
of the slot type (NOT_INIT and SCALAR_VALUE respectively). Fix the
check.
Fixes: 01f810ace9 ("bpf: Allow variable-offset stack access")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221103191013.1236066-5-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When support was added for spilled PTR_TO_BTF_ID to be accessed by
helper memory access, the stack slot was not overwritten to STACK_MISC
(and that too is only safe when env->allow_ptr_leaks is true).
This means that helpers who take ARG_PTR_TO_MEM and write to it may
essentially overwrite the value while the verifier continues to track
the slot for spilled register.
This can cause issues when PTR_TO_BTF_ID is spilled to stack, and then
overwritten by helper write access, which can then be passed to BPF
helpers or kfuncs.
Handle this by falling back to the case introduced in a later commit,
which will also handle PTR_TO_BTF_ID along with other pointer types,
i.e. cd17d38f8b ("bpf: Permits pointers on stack for helper calls").
Finally, include a comment on why REG_LIVE_WRITTEN is not being set when
clobber is set to true. In short, the reason is that while when clobber
is unset, we know that we won't be writing, when it is true, we *may*
write to any of the stack slots in that range. It may be a partial or
complete write, to just one or many stack slots.
We cannot be sure, hence to be conservative, we leave things as is and
never set REG_LIVE_WRITTEN for any stack slot. However, clobber still
needs to reset them to STACK_MISC assuming writes happened. However read
marks still need to be propagated upwards from liveness point of view,
as parent stack slot's contents may still continue to matter to child
states.
Cc: Yonghong Song <yhs@meta.com>
Fixes: 1d68f22b3d ("bpf: Handle spilled PTR_TO_BTF_ID properly when checking stack_boundary")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221103191013.1236066-4-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This is useful in particular to mark the pointer as volatile, so that
compiler treats each load and store to the field as a volatile access.
The alternative is having to define and use READ_ONCE and WRITE_ONCE in
the BPF program.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20221103191013.1236066-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Some helper functions will allocate memory. To avoid memory leaks, the
verifier requires the eBPF program to release these memories by calling
the corresponding helper functions.
When a resource is released, all pointer registers corresponding to the
resource should be invalidated. The verifier use release_references() to
do this job, by apply __mark_reg_unknown() to each relevant register.
It will give these registers the type of SCALAR_VALUE. A register that
will contain a pointer value at runtime, but of type SCALAR_VALUE, which
may allow the unprivileged user to get a kernel pointer by storing this
register into a map.
Using __mark_reg_not_init() while NOT allow_ptr_leaks can mitigate this
problem.
Fixes: fd978bf7fd ("bpf: Add reference tracking to verifier")
Signed-off-by: Youlin Li <liulin063@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20221103093440.3161-1-liulin063@gmail.com
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:
====================
bpf-next 2022-11-02
We've added 70 non-merge commits during the last 14 day(s) which contain
a total of 96 files changed, 3203 insertions(+), 640 deletions(-).
The main changes are:
1) Make cgroup local storage available to non-cgroup attached BPF programs
such as tc BPF ones, from Yonghong Song.
2) Avoid unnecessary deadlock detection and failures wrt BPF task storage
helpers, from Martin KaFai Lau.
3) Add LLVM disassembler as default library for dumping JITed code
in bpftool, from Quentin Monnet.
4) Various kprobe_multi_link fixes related to kernel modules,
from Jiri Olsa.
5) Optimize x86-64 JIT with emitting BMI2-based shift instructions,
from Jie Meng.
6) Improve BPF verifier's memory type compatibility for map key/value
arguments, from Dave Marchevsky.
7) Only create mmap-able data section maps in libbpf when data is exposed
via skeletons, from Andrii Nakryiko.
8) Add an autoattach option for bpftool to load all object assets,
from Wang Yufen.
9) Various memory handling fixes for libbpf and BPF selftests,
from Xu Kuohai.
10) Initial support for BPF selftest's vmtest.sh on arm64,
from Manu Bretelle.
11) Improve libbpf's BTF handling to dedup identical structs,
from Alan Maguire.
12) Add BPF CI and denylist documentation for BPF selftests,
from Daniel Müller.
13) Check BPF cpumap max_entries before doing allocation work,
from Florian Lehner.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (70 commits)
samples/bpf: Fix typo in README
bpf: Remove the obsolte u64_stats_fetch_*_irq() users.
bpf: check max_entries before allocating memory
bpf: Fix a typo in comment for DFS algorithm
bpftool: Fix spelling mistake "disasembler" -> "disassembler"
selftests/bpf: Fix bpftool synctypes checking failure
selftests/bpf: Panic on hard/soft lockup
docs/bpf: Add documentation for new cgroup local storage
selftests/bpf: Add test cgrp_local_storage to DENYLIST.s390x
selftests/bpf: Add selftests for new cgroup local storage
selftests/bpf: Fix test test_libbpf_str/bpf_map_type_str
bpftool: Support new cgroup local storage
libbpf: Support new cgroup local storage
bpf: Implement cgroup storage available to non-cgroup-attached bpf progs
bpf: Refactor some inode/task/sk storage functions for reuse
bpf: Make struct cgroup btf id global
selftests/bpf: Tracing prog can still do lookup under busy lock
selftests/bpf: Ensure no task storage failure for bpf_lsm.s prog due to deadlock detection
bpf: Add new bpf_task_storage_delete proto with no deadlock detection
bpf: bpf_task_storage_delete_recur does lookup first before the deadlock check
...
====================
Link: https://lore.kernel.org/r/20221102062120.5724-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
If an error (NULL) is returned by krealloc(), callers of realloc_array()
were setting their allocation pointers to NULL, but on error krealloc()
does not touch the original allocation. This would result in a memory
resource leak. Instead, free the old allocation on the error handling
path.
The memory leak information is as follows as also reported by Zhengchao:
unreferenced object 0xffff888019801800 (size 256):
comm "bpf_repo", pid 6490, jiffies 4294959200 (age 17.170s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<00000000b211474b>] __kmalloc_node_track_caller+0x45/0xc0
[<0000000086712a0b>] krealloc+0x83/0xd0
[<00000000139aab02>] realloc_array+0x82/0xe2
[<00000000b1ca41d1>] grow_stack_state+0xfb/0x186
[<00000000cd6f36d2>] check_mem_access.cold+0x141/0x1341
[<0000000081780455>] do_check_common+0x5358/0xb350
[<0000000015f6b091>] bpf_check.cold+0xc3/0x29d
[<000000002973c690>] bpf_prog_load+0x13db/0x2240
[<00000000028d1644>] __sys_bpf+0x1605/0x4ce0
[<00000000053f29bd>] __x64_sys_bpf+0x75/0xb0
[<0000000056fedaf5>] do_syscall_64+0x35/0x80
[<000000002bd58261>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
Fixes: c69431aab6 ("bpf: verifier: Improve function state reallocation")
Reported-by: Zhengchao Shao <shaozhengchao@huawei.com>
Reported-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Bill Wendling <morbo@google.com>
Cc: Lorenz Bauer <oss@lmb.io>
Link: https://lore.kernel.org/bpf/20221029025433.2533810-1-keescook@chromium.org
Now that the 32bit UP oddity is gone and 32bit uses always a sequence
count, there is no need for the fetch_irq() variants anymore.
Convert to the regular interface.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/bpf/20221026123110.331690-1-bigeasy@linutronix.de
For maps of type BPF_MAP_TYPE_CPUMAP memory is allocated first before
checking the max_entries argument. If then max_entries is greater than
NR_CPUS additional work needs to be done to free allocated memory before
an error is returned.
This changes moves the check on max_entries before the allocation
happens.
Signed-off-by: Florian Lehner <dev@der-flo.net>
Link: https://lore.kernel.org/r/20221028183405.59554-1-dev@der-flo.net
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
There is a typo in comment for DFS algorithm in bpf/verifier.c. The top
element should not be popped until all its neighbors have been checked.
Fix it.
Fixes: 475fb78fbf ("bpf: verifier (add branch/goto checks)")
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221027034458.2925218-1-xukuohai@huaweicloud.com
Similar to sk/inode/task storage, implement similar cgroup local storage.
There already exists a local storage implementation for cgroup-attached
bpf programs. See map type BPF_MAP_TYPE_CGROUP_STORAGE and helper
bpf_get_local_storage(). But there are use cases such that non-cgroup
attached bpf progs wants to access cgroup local storage data. For example,
tc egress prog has access to sk and cgroup. It is possible to use
sk local storage to emulate cgroup local storage by storing data in socket.
But this is a waste as it could be lots of sockets belonging to a particular
cgroup. Alternatively, a separate map can be created with cgroup id as the key.
But this will introduce additional overhead to manipulate the new map.
A cgroup local storage, similar to existing sk/inode/task storage,
should help for this use case.
The life-cycle of storage is managed with the life-cycle of the
cgroup struct. i.e. the storage is destroyed along with the owning cgroup
with a call to bpf_cgrp_storage_free() when cgroup itself
is deleted.
The userspace map operations can be done by using a cgroup fd as a key
passed to the lookup, update and delete operations.
Typically, the following code is used to get the current cgroup:
struct task_struct *task = bpf_get_current_task_btf();
... task->cgroups->dfl_cgrp ...
and in structure task_struct definition:
struct task_struct {
....
struct css_set __rcu *cgroups;
....
}
With sleepable program, accessing task->cgroups is not protected by rcu_read_lock.
So the current implementation only supports non-sleepable program and supporting
sleepable program will be the next step together with adding rcu_read_lock
protection for rcu tagged structures.
Since map name BPF_MAP_TYPE_CGROUP_STORAGE has been used for old cgroup local
storage support, the new map name BPF_MAP_TYPE_CGRP_STORAGE is used
for cgroup storage available to non-cgroup-attached bpf programs. The old
cgroup storage supports bpf_get_local_storage() helper to get the cgroup data.
The new cgroup storage helper bpf_cgrp_storage_get() can provide similar
functionality. While old cgroup storage pre-allocates storage memory, the new
mechanism can also pre-allocate with a user space bpf_map_update_elem() call
to avoid potential run-time memory allocation failure.
Therefore, the new cgroup storage can provide all functionality w.r.t.
the old one. So in uapi bpf.h, the old BPF_MAP_TYPE_CGROUP_STORAGE is alias to
BPF_MAP_TYPE_CGROUP_STORAGE_DEPRECATED to indicate the old cgroup storage can
be deprecated since the new one can provide the same functionality.
Acked-by: David Vernet <void@manifault.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221026042850.673791-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Refactor codes so that inode/task/sk storage implementation
can maximally share the same code. I also added some comments
in new function bpf_local_storage_unlink_nolock() to make
codes easy to understand. There is no functionality change.
Acked-by: David Vernet <void@manifault.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221026042845.672944-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Make struct cgroup btf id global so later patch can reuse
the same btf id.
Acked-by: David Vernet <void@manifault.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221026042840.672602-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The bpf_lsm and bpf_iter do not recur that will cause a deadlock.
The situation is similar to the bpf_pid_task_storage_delete_elem()
which is called from the syscall map_delete_elem. It does not need
deadlock detection. Otherwise, it will cause unnecessary failure
when calling the bpf_task_storage_delete() helper.
This patch adds bpf_task_storage_delete proto that does not do deadlock
detection. It will be used by bpf_lsm and bpf_iter program.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20221025184524.3526117-8-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Similar to the earlier change in bpf_task_storage_get_recur.
This patch changes bpf_task_storage_delete_recur such that it
does the lookup first. It only returns -EBUSY if it needs to
take the spinlock to do the deletion when potential deadlock
is detected.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20221025184524.3526117-7-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The bpf_lsm and bpf_iter do not recur that will cause a deadlock.
The situation is similar to the bpf_pid_task_storage_lookup_elem()
which is called from the syscall map_lookup_elem. It does not need
deadlock detection. Otherwise, it will cause unnecessary failure
when calling the bpf_task_storage_get() helper.
This patch adds bpf_task_storage_get proto that does not do deadlock
detection. It will be used by bpf_lsm and bpf_iter programs.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20221025184524.3526117-6-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
bpf_task_storage_get() does a lookup and optionally inserts
new data if BPF_LOCAL_STORAGE_GET_F_CREATE is present.
During lookup, it will cache the lookup result and caching requires to
acquire a spinlock. When potential deadlock is detected (by the
bpf_task_storage_busy pcpu-counter added in
commit bc235cdb42 ("bpf: Prevent deadlock from recursive bpf_task_storage_[get|delete]")),
the current behavior is returning NULL immediately to avoid deadlock. It is
too pessimistic. This patch will go ahead to do a lookup (which is a
lockless operation) but it will avoid caching it in order to avoid
acquiring the spinlock.
When lookup fails to find the data and BPF_LOCAL_STORAGE_GET_F_CREATE
is set, an insertion is needed and this requires acquiring a spinlock.
This patch will still return NULL when a potential deadlock is detected.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20221025184524.3526117-5-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch creates a new function __bpf_task_storage_get() and
moves the core logic of the existing bpf_task_storage_get()
into this new function. This new function will be shared
by another new helper proto in the latter patch.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20221025184524.3526117-4-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch adds the "_recur" naming to the bpf_task_storage_{get,delete}
proto. In a latter patch, they will only be used by the tracing
programs that requires a deadlock detection because a tracing
prog may use bpf_task_storage_{get,delete} recursively and cause a
deadlock.
Another following patch will add a different helper proto for the non
tracing programs because they do not need the deadlock prevention.
This patch does this rename to prepare for this future proto
additions.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20221025184524.3526117-3-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The commit 64696c40d0 ("bpf: Add __bpf_prog_{enter,exit}_struct_ops for struct_ops trampoline")
removed prog->active check for struct_ops prog. The bpf_lsm
and bpf_iter is also using trampoline. Like struct_ops, the bpf_lsm
and bpf_iter have fixed hooks for the prog to attach. The
kernel does not call the same hook in a recursive way.
This patch also removes the prog->active check for
bpf_lsm and bpf_iter.
A later patch has a test to reproduce the recursion issue
for a sleepable bpf_lsm program.
This patch appends the '_recur' naming to the existing
enter and exit functions that track the prog->active counter.
New __bpf_prog_{enter,exit}[_sleepable] function are
added to skip the prog->active tracking. The '_struct_ops'
version is also removed.
It also moves the decision on picking the enter and exit function to
the new bpf_trampoline_{enter,exit}(). It returns the '_recur' ones
for all tracing progs to use. For bpf_lsm, bpf_iter,
struct_ops (no prog->active tracking after 64696c40d0), and
bpf_lsm_cgroup (no prog->active tracking after 69fd337a97),
it will return the functions that don't track the prog->active.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20221025184524.3526117-2-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Alexei Starovoitov says:
====================
pull-request: bpf 2022-10-23
We've added 7 non-merge commits during the last 18 day(s) which contain
a total of 8 files changed, 69 insertions(+), 5 deletions(-).
The main changes are:
1) Wait for busy refill_work when destroying bpf memory allocator, from Hou.
2) Allow bpf_user_ringbuf_drain() callbacks to return 1, from David.
3) Fix dispatcher patchable function entry to 5 bytes nop, from Jiri.
4) Prevent decl_tag from being referenced in func_proto, from Stanislav.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
bpf: Use __llist_del_all() whenever possbile during memory draining
bpf: Wait for busy refill_work when destroying bpf memory allocator
bpf: Fix dispatcher patchable function entry to 5 bytes nop
bpf: prevent decl_tag from being referenced in func_proto
selftests/bpf: Add reproducer for decl_tag in func_proto return type
selftests/bpf: Make bpf_user_ringbuf_drain() selftest callback return 1
bpf: Allow bpf_user_ringbuf_drain() callbacks to return 1
====================
Link: https://lore.kernel.org/r/20221023192244.81137-1-alexei.starovoitov@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
After the previous patch, which added PTR_TO_MEM | MEM_ALLOC type
map_key_value_types, the only difference between map_key_value_types and
mem_types sets is PTR_TO_BUF and PTR_TO_MEM, which are in the latter set
but not the former.
Helpers which expect ARG_PTR_TO_MAP_KEY or ARG_PTR_TO_MAP_VALUE
already effectively expect a valid blob of arbitrary memory that isn't
necessarily explicitly associated with a map. When validating a
PTR_TO_MAP_{KEY,VALUE} arg, the verifier expects meta->map_ptr to have
already been set, either by an earlier ARG_CONST_MAP_PTR arg, or custom
logic like that in process_timer_func or process_kptr_func.
So let's get rid of map_key_value_types and just use mem_types for those
args.
This has the effect of adding PTR_TO_BUF and PTR_TO_MEM to the set of
compatible types for ARG_PTR_TO_MAP_KEY and ARG_PTR_TO_MAP_VALUE.
PTR_TO_BUF is used by various bpf_iter implementations to represent a
chunk of valid r/w memory in ctx args for iter prog.
PTR_TO_MEM is used by networking, tracing, and ringbuf helpers to
represent a chunk of valid memory. The PTR_TO_MEM | MEM_ALLOC
type added in previous commit is specific to ringbuf helpers.
Presence or absence of MEM_ALLOC doesn't change the validity of using
PTR_TO_MEM as a map_{key,val} input.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221020160721.4030492-2-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch adds support for the following pattern:
struct some_data *data = bpf_ringbuf_reserve(&ringbuf, sizeof(struct some_data, 0));
if (!data)
return;
bpf_map_lookup_elem(&another_map, &data->some_field);
bpf_ringbuf_submit(data);
Currently the verifier does not consider bpf_ringbuf_reserve's
PTR_TO_MEM | MEM_ALLOC ret type a valid key input to bpf_map_lookup_elem.
Since PTR_TO_MEM is by definition a valid region of memory, it is safe
to use it as a key for lookups.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221020160721.4030492-1-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Except for waiting_for_gp list, there are no concurrent operations on
free_by_rcu, free_llist and free_llist_extra lists, so use
__llist_del_all() instead of llist_del_all(). waiting_for_gp list can be
deleted by RCU callback concurrently, so still use llist_del_all().
Acked-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20221021114913.60508-3-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
A busy irq work is an unfinished irq work and it can be either in the
pending state or in the running state. When destroying bpf memory
allocator, refill_work may be busy for PREEMPT_RT kernel in which irq
work is invoked in a per-CPU RT-kthread. It is also possible for kernel
with arch_irq_work_has_interrupt() being false (e.g. 1-cpu arm32 host or
mips) and irq work is inovked in timer interrupt.
The busy refill_work leads to various issues. The obvious one is that
there will be concurrent operations on free_by_rcu and free_list between
irq work and memory draining. Another one is call_rcu_in_progress will
not be reliable for the checking of pending RCU callback because
do_call_rcu() may have not been invoked by irq work yet. The other is
there will be use-after-free if irq work is freed before the callback
of irq work is invoked as shown below:
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 12ab94067 P4D 12ab94067 PUD 1796b4067 PMD 0
Oops: 0010 [#1] PREEMPT_RT SMP
CPU: 5 PID: 64 Comm: irq_work/5 Not tainted 6.0.0-rt11+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffadc080293e78 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffffcdc07fb6a388 RCX: ffffa05000a2e000
RDX: ffffa05000a2e000 RSI: ffffffff96cc9827 RDI: ffffcdc07fb6a388
......
Call Trace:
<TASK>
irq_work_single+0x24/0x60
irq_work_run_list+0x24/0x30
run_irq_workd+0x23/0x30
smpboot_thread_fn+0x203/0x300
kthread+0x126/0x150
ret_from_fork+0x1f/0x30
</TASK>
Considering the ease of concurrency handling, no overhead for
irq_work_sync() under non-PREEMPT_RT kernel and has-irq-work-interrupt
kernel and the short wait time used for irq_work_sync() under PREEMPT_RT
(When running two test_maps on PREEMPT_RT kernel and 72-cpus host, the
max wait time is about 8ms and the 99th percentile is 10us), just using
irq_work_sync() to wait for busy refill_work to complete before memory
draining and memory freeing.
Fixes: 7c8199e24f ("bpf: Introduce any context BPF specific memory allocator.")
Acked-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20221021114913.60508-2-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The patchable_function_entry(5) might output 5 single nop
instructions (depends on toolchain), which will clash with
bpf_arch_text_poke check for 5 bytes nop instruction.
Adding early init call for dispatcher that checks and change
the patchable entry into expected 5 nop instruction if needed.
There's no need to take text_mutex, because we are using it
in early init call which is called at pre-smp time.
Fixes: ceea991a01 ("bpf: Move bpf_dispatcher function out of ftrace locations")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221018075934.574415-1-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Merge tag 'for-netdev' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:
====================
pull-request: bpf-next 2022-10-18
We've added 33 non-merge commits during the last 14 day(s) which contain
a total of 31 files changed, 874 insertions(+), 538 deletions(-).
The main changes are:
1) Add RCU grace period chaining to BPF to wait for the completion
of access from both sleepable and non-sleepable BPF programs,
from Hou Tao & Paul E. McKenney.
2) Improve helper UAPI by explicitly defining BPF_FUNC_xxx integer
values. In the wild we have seen OS vendors doing buggy backports
where helper call numbers mismatched. This is an attempt to make
backports more foolproof, from Andrii Nakryiko.
3) Add libbpf *_opts API-variants for bpf_*_get_fd_by_id() functions,
from Roberto Sassu.
4) Fix libbpf's BTF dumper for structs with padding-only fields,
from Eduard Zingerman.
5) Fix various libbpf bugs which have been found from fuzzing with
malformed BPF object files, from Shung-Hsi Yu.
6) Clean up an unneeded check on existence of SSE2 in BPF x86-64 JIT,
from Jie Meng.
7) Fix various ASAN bugs in both libbpf and selftests when running
the BPF selftest suite on arm64, from Xu Kuohai.
8) Fix missing bpf_iter_vma_offset__destroy() call in BPF iter selftest
and use in-skeleton link pointer to remove an explicit bpf_link__destroy(),
from Jiri Olsa.
9) Fix BPF CI breakage by pointing to iptables-legacy instead of relying
on symlinked iptables which got upgraded to iptables-nft,
from Martin KaFai Lau.
10) Minor BPF selftest improvements all over the place, from various others.
* tag 'for-netdev' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (33 commits)
bpf/docs: Update README for most recent vmtest.sh
bpf: Use rcu_trace_implies_rcu_gp() for program array freeing
bpf: Use rcu_trace_implies_rcu_gp() in local storage map
bpf: Use rcu_trace_implies_rcu_gp() in bpf memory allocator
rcu-tasks: Provide rcu_trace_implies_rcu_gp()
selftests/bpf: Use sys_pidfd_open() helper when possible
libbpf: Fix null-pointer dereference in find_prog_by_sec_insn()
libbpf: Deal with section with no data gracefully
libbpf: Use elf_getshdrnum() instead of e_shnum
selftest/bpf: Fix error usage of ASSERT_OK in xdp_adjust_tail.c
selftests/bpf: Fix error failure of case test_xdp_adjust_tail_grow
selftest/bpf: Fix memory leak in kprobe_multi_test
selftests/bpf: Fix memory leak caused by not destroying skeleton
libbpf: Fix memory leak in parse_usdt_arg()
libbpf: Fix use-after-free in btf_dump_name_dups
selftests/bpf: S/iptables/iptables-legacy/ in the bpf_nf and xdp_synproxy test
selftests/bpf: Alphabetize DENYLISTs
selftests/bpf: Add tests for _opts variants of bpf_*_get_fd_by_id()
libbpf: Introduce bpf_link_get_fd_by_id_opts()
libbpf: Introduce bpf_btf_get_fd_by_id_opts()
...
====================
Link: https://lore.kernel.org/r/20221018210631.11211-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
To support both sleepable and normal uprobe bpf program, the freeing of
trace program array chains a RCU-tasks-trace grace period and a normal
RCU grace period one after the other.
With the introduction of rcu_trace_implies_rcu_gp(),
__bpf_prog_array_free_sleepable_cb() can check whether or not a normal
RCU grace period has also passed after a RCU-tasks-trace grace period
has passed. If it is true, it is safe to invoke kfree() directly.
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20221014113946.965131-5-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Local storage map is accessible for both sleepable and non-sleepable bpf
program, and its memory is freed by using both call_rcu_tasks_trace() and
kfree_rcu() to wait for both RCU-tasks-trace grace period and RCU grace
period to pass.
With the introduction of rcu_trace_implies_rcu_gp(), both
bpf_selem_free_rcu() and bpf_local_storage_free_rcu() can check whether
or not a normal RCU grace period has also passed after a RCU-tasks-trace
grace period has passed. If it is true, it is safe to call kfree()
directly.
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20221014113946.965131-4-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The memory free logic in bpf memory allocator chains a RCU Tasks Trace
grace period and a normal RCU grace period one after the other, so it
can ensure that both sleepable and non-sleepable programs have finished.
With the introduction of rcu_trace_implies_rcu_gp(),
__free_rcu_tasks_trace() can check whether or not a normal RCU grace
period has also passed after a RCU Tasks Trace grace period has passed.
If it is true, freeing these elements directly, else freeing through
call_rcu().
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20221014113946.965131-3-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
* Fix a recent regression where a sleeping kernfs function is called with
css_set_lock (spinlock) held.
* Revert the commit to enable cgroup1 support for cgroup_get_from_fd/file().
Multiple users assume that the lookup only works for cgroup2 and breaks
when fed a cgroup1 file. Instead, introduce a separate set of functions to
lookup both v1 and v2 and use them where the user explicitly wants to
support both versions.
* Compat update for tools/perf/util/bpf_skel/bperf_cgroup.bpf.c.
* Add Josef Bacik as a blkcg maintainer.
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Merge tag 'cgroup-for-6.1-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo:
- Fix a recent regression where a sleeping kernfs function is called
with css_set_lock (spinlock) held
- Revert the commit to enable cgroup1 support for cgroup_get_from_fd/file()
Multiple users assume that the lookup only works for cgroup2 and
breaks when fed a cgroup1 file. Instead, introduce a separate set of
functions to lookup both v1 and v2 and use them where the user
explicitly wants to support both versions.
- Compat update for tools/perf/util/bpf_skel/bperf_cgroup.bpf.c.
- Add Josef Bacik as a blkcg maintainer.
* tag 'cgroup-for-6.1-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
blkcg: Update MAINTAINERS entry
mm: cgroup: fix comments for get from fd/file helpers
perf stat: Support old kernels for bperf cgroup counting
bpf: cgroup_iter: support cgroup1 using cgroup fd
cgroup: add cgroup_v1v2_get_from_[fd/file]()
Revert "cgroup: enable cgroup_get_from_file() on cgroup1"
cgroup: Reorganize css_set_lock and kernfs path processing
The bpf_user_ringbuf_drain() helper function allows a BPF program to
specify a callback that is invoked when draining entries from a
BPF_MAP_TYPE_USER_RINGBUF ring buffer map. The API is meant to allow the
callback to return 0 if it wants to continue draining samples, and 1 if
it's done draining. Unfortunately, bpf_user_ringbuf_drain() landed shortly
after commit 1bfe26fb08 ("bpf: Add verifier support for custom
callback return range"), which changed the default behavior of callbacks
to only support returning 0.
This patch corrects that oversight by allowing bpf_user_ringbuf_drain()
callbacks to return 0 or 1. A follow-on patch will update the
user_ringbuf selftests to also return 1 from a bpf_user_ringbuf_drain()
callback to prevent this from regressing in the future.
Fixes: 2057156738 ("bpf: Add bpf_user_ringbuf_drain() helper")
Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221012232015.1510043-2-void@manifault.com
The prandom_u32() function has been a deprecated inline wrapper around
get_random_u32() for several releases now, and compiles down to the
exact same code. Replace the deprecated wrapper with a direct call to
the real function. The same also applies to get_random_int(), which is
just a wrapper around get_random_u32(). This was done as a basic find
and replace.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk> # for sch_cake
Acked-by: Chuck Lever <chuck.lever@oracle.com> # for nfsd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com> # for thunderbolt
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Acked-by: Helge Deller <deller@gmx.de> # for parisc
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
the minimum required bytes from the RNG and avoids divisions. This was
done mechanically with this coccinelle script:
@basic@
expression E;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u64;
@@
(
- ((T)get_random_u32() % (E))
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ((E) - 1))
+ prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2)
|
- ((u64)(E) * get_random_u32() >> 32)
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ~PAGE_MASK)
+ prandom_u32_max(PAGE_SIZE)
)
@multi_line@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
identifier RAND;
expression E;
@@
- RAND = get_random_u32();
... when != RAND
- RAND %= (E);
+ RAND = prandom_u32_max(E);
// Find a potential literal
@literal_mask@
expression LITERAL;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
position p;
@@
((T)get_random_u32()@p & (LITERAL))
// Add one to the literal.
@script:python add_one@
literal << literal_mask.LITERAL;
RESULT;
@@
value = None
if literal.startswith('0x'):
value = int(literal, 16)
elif literal[0] in '123456789':
value = int(literal, 10)
if value is None:
print("I don't know how to handle %s" % (literal))
cocci.include_match(False)
elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1:
print("Skipping 0x%x for cleanup elsewhere" % (value))
cocci.include_match(False)
elif value & (value + 1) != 0:
print("Skipping 0x%x because it's not a power of two minus one" % (value))
cocci.include_match(False)
elif literal.startswith('0x'):
coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1))
else:
coccinelle.RESULT = cocci.make_expr("%d" % (value + 1))
// Replace the literal mask with the calculated result.
@plus_one@
expression literal_mask.LITERAL;
position literal_mask.p;
expression add_one.RESULT;
identifier FUNC;
@@
- (FUNC()@p & (LITERAL))
+ prandom_u32_max(RESULT)
@collapse_ret@
type T;
identifier VAR;
expression E;
@@
{
- T VAR;
- VAR = (E);
- return VAR;
+ return E;
}
@drop_var@
type T;
identifier VAR;
@@
{
- T VAR;
... when != VAR
}
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: KP Singh <kpsingh@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4 and sbitmap
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> # for drbd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Use cgroup_v1v2_get_from_fd() in cgroup_iter to support attaching to
both cgroup v1 and v2 using fds.
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
linux-next for a couple of months without, to my knowledge, any negative
reports (or any positive ones, come to that).
- Also the Maple Tree from Liam R. Howlett. An overlapping range-based
tree for vmas. It it apparently slight more efficient in its own right,
but is mainly targeted at enabling work to reduce mmap_lock contention.
Liam has identified a number of other tree users in the kernel which
could be beneficially onverted to mapletrees.
Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat
(https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com).
This has yet to be addressed due to Liam's unfortunately timed
vacation. He is now back and we'll get this fixed up.
- Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses
clang-generated instrumentation to detect used-unintialized bugs down to
the single bit level.
KMSAN keeps finding bugs. New ones, as well as the legacy ones.
- Yang Shi adds a userspace mechanism (madvise) to induce a collapse of
memory into THPs.
- Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to support
file/shmem-backed pages.
- userfaultfd updates from Axel Rasmussen
- zsmalloc cleanups from Alexey Romanov
- cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and memory-failure
- Huang Ying adds enhancements to NUMA balancing memory tiering mode's
page promotion, with a new way of detecting hot pages.
- memcg updates from Shakeel Butt: charging optimizations and reduced
memory consumption.
- memcg cleanups from Kairui Song.
- memcg fixes and cleanups from Johannes Weiner.
- Vishal Moola provides more folio conversions
- Zhang Yi removed ll_rw_block() :(
- migration enhancements from Peter Xu
- migration error-path bugfixes from Huang Ying
- Aneesh Kumar added ability for a device driver to alter the memory
tiering promotion paths. For optimizations by PMEM drivers, DRM
drivers, etc.
- vma merging improvements from Jakub Matěn.
- NUMA hinting cleanups from David Hildenbrand.
- xu xin added aditional userspace visibility into KSM merging activity.
- THP & KSM code consolidation from Qi Zheng.
- more folio work from Matthew Wilcox.
- KASAN updates from Andrey Konovalov.
- DAMON cleanups from Kaixu Xia.
- DAMON work from SeongJae Park: fixes, cleanups.
- hugetlb sysfs cleanups from Muchun Song.
- Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core.
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Merge tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Yu Zhao's Multi-Gen LRU patches are here. They've been under test in
linux-next for a couple of months without, to my knowledge, any
negative reports (or any positive ones, come to that).
- Also the Maple Tree from Liam Howlett. An overlapping range-based
tree for vmas. It it apparently slightly more efficient in its own
right, but is mainly targeted at enabling work to reduce mmap_lock
contention.
Liam has identified a number of other tree users in the kernel which
could be beneficially onverted to mapletrees.
Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat
at [1]. This has yet to be addressed due to Liam's unfortunately
timed vacation. He is now back and we'll get this fixed up.
- Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses
clang-generated instrumentation to detect used-unintialized bugs down
to the single bit level.
KMSAN keeps finding bugs. New ones, as well as the legacy ones.
- Yang Shi adds a userspace mechanism (madvise) to induce a collapse of
memory into THPs.
- Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to
support file/shmem-backed pages.
- userfaultfd updates from Axel Rasmussen
- zsmalloc cleanups from Alexey Romanov
- cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and
memory-failure
- Huang Ying adds enhancements to NUMA balancing memory tiering mode's
page promotion, with a new way of detecting hot pages.
- memcg updates from Shakeel Butt: charging optimizations and reduced
memory consumption.
- memcg cleanups from Kairui Song.
- memcg fixes and cleanups from Johannes Weiner.
- Vishal Moola provides more folio conversions
- Zhang Yi removed ll_rw_block() :(
- migration enhancements from Peter Xu
- migration error-path bugfixes from Huang Ying
- Aneesh Kumar added ability for a device driver to alter the memory
tiering promotion paths. For optimizations by PMEM drivers, DRM
drivers, etc.
- vma merging improvements from Jakub Matěn.
- NUMA hinting cleanups from David Hildenbrand.
- xu xin added aditional userspace visibility into KSM merging
activity.
- THP & KSM code consolidation from Qi Zheng.
- more folio work from Matthew Wilcox.
- KASAN updates from Andrey Konovalov.
- DAMON cleanups from Kaixu Xia.
- DAMON work from SeongJae Park: fixes, cleanups.
- hugetlb sysfs cleanups from Muchun Song.
- Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core.
Link: https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com [1]
* tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (555 commits)
hugetlb: allocate vma lock for all sharable vmas
hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer
hugetlb: fix vma lock handling during split vma and range unmapping
mglru: mm/vmscan.c: fix imprecise comments
mm/mglru: don't sync disk for each aging cycle
mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol
mm: memcontrol: use do_memsw_account() in a few more places
mm: memcontrol: deprecate swapaccounting=0 mode
mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled
mm/secretmem: remove reduntant return value
mm/hugetlb: add available_huge_pages() func
mm: remove unused inline functions from include/linux/mm_inline.h
selftests/vm: add selftest for MADV_COLLAPSE of uffd-minor memory
selftests/vm: add file/shmem MADV_COLLAPSE selftest for cleared pmd
selftests/vm: add thp collapse shmem testing
selftests/vm: add thp collapse file and tmpfs testing
selftests/vm: modularize thp collapse memory operations
selftests/vm: dedup THP helpers
mm/khugepaged: add tracepoint to hpage_collapse_scan_file()
mm/madvise: add file and shmem support to MADV_COLLAPSE
...
- PMU driver updates:
- Add AMD Last Branch Record Extension Version 2 (LbrExtV2)
feature support for Zen 4 processors.
- Extend the perf ABI to provide branch speculation information,
if available, and use this on CPUs that have it (eg. LbrExtV2).
- Improve Intel PEBS TSC timestamp handling & integration.
- Add Intel Raptor Lake S CPU support.
- Add 'perf mem' and 'perf c2c' memory profiling support on
AMD CPUs by utilizing IBS tagged load/store samples.
- Clean up & optimize various x86 PMU details.
- HW breakpoints:
- Big rework to optimize the code for systems with hundreds of CPUs and
thousands of breakpoints:
- Replace the nr_bp_mutex global mutex with the bp_cpuinfo_sem
per-CPU rwsem that is read-locked during most of the key operations.
- Improve the O(#cpus * #tasks) logic in toggle_bp_slot()
and fetch_bp_busy_slots().
- Apply micro-optimizations & cleanups.
- Misc cleanups & enhancements.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'perf-core-2022-10-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf events updates from Ingo Molnar:
"PMU driver updates:
- Add AMD Last Branch Record Extension Version 2 (LbrExtV2) feature
support for Zen 4 processors.
- Extend the perf ABI to provide branch speculation information, if
available, and use this on CPUs that have it (eg. LbrExtV2).
- Improve Intel PEBS TSC timestamp handling & integration.
- Add Intel Raptor Lake S CPU support.
- Add 'perf mem' and 'perf c2c' memory profiling support on AMD CPUs
by utilizing IBS tagged load/store samples.
- Clean up & optimize various x86 PMU details.
HW breakpoints:
- Big rework to optimize the code for systems with hundreds of CPUs
and thousands of breakpoints:
- Replace the nr_bp_mutex global mutex with the bp_cpuinfo_sem
per-CPU rwsem that is read-locked during most of the key
operations.
- Improve the O(#cpus * #tasks) logic in toggle_bp_slot() and
fetch_bp_busy_slots().
- Apply micro-optimizations & cleanups.
- Misc cleanups & enhancements"
* tag 'perf-core-2022-10-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (75 commits)
perf/hw_breakpoint: Annotate tsk->perf_event_mutex vs ctx->mutex
perf: Fix pmu_filter_match()
perf: Fix lockdep_assert_event_ctx()
perf/x86/amd/lbr: Adjust LBR regardless of filtering
perf/x86/utils: Fix uninitialized var in get_branch_type()
perf/uapi: Define PERF_MEM_SNOOPX_PEER in kernel header file
perf/x86/amd: Support PERF_SAMPLE_PHY_ADDR
perf/x86/amd: Support PERF_SAMPLE_ADDR
perf/x86/amd: Support PERF_SAMPLE_{WEIGHT|WEIGHT_STRUCT}
perf/x86/amd: Support PERF_SAMPLE_DATA_SRC
perf/x86/amd: Add IBS OP_DATA2 DataSrc bit definitions
perf/mem: Introduce PERF_MEM_LVLNUM_{EXTN_MEM|IO}
perf/x86/uncore: Add new Raptor Lake S support
perf/x86/cstate: Add new Raptor Lake S support
perf/x86/msr: Add new Raptor Lake S support
perf/x86: Add new Raptor Lake S support
bpf: Check flags for branch stack in bpf_read_branch_records helper
perf, hw_breakpoint: Fix use-after-free if perf_event_open() fails
perf: Use sample_flags for raw_data
perf: Use sample_flags for addr
...
Core
----
- Introduce and use a single page frag cache for allocating small skb
heads, clawing back the 10-20% performance regression in UDP flood
test from previous fixes.
- Run packets which already went thru HW coalescing thru SW GRO.
This significantly improves TCP segment coalescing and simplifies
deployments as different workloads benefit from HW or SW GRO.
- Shrink the size of the base zero-copy send structure.
- Move TCP init under a new slow / sleepable version of DO_ONCE().
BPF
---
- Add BPF-specific, any-context-safe memory allocator.
- Add helpers/kfuncs for PKCS#7 signature verification from BPF
programs.
- Define a new map type and related helpers for user space -> kernel
communication over a ring buffer (BPF_MAP_TYPE_USER_RINGBUF).
- Allow targeting BPF iterators to loop through resources of one
task/thread.
- Add ability to call selected destructive functions.
Expose crash_kexec() to allow BPF to trigger a kernel dump.
Use CAP_SYS_BOOT check on the loading process to judge permissions.
- Enable BPF to collect custom hierarchical cgroup stats efficiently
by integrating with the rstat framework.
- Support struct arguments for trampoline based programs.
Only structs with size <= 16B and x86 are supported.
- Invoke cgroup/connect{4,6} programs for unprivileged ICMP ping
sockets (instead of just TCP and UDP sockets).
- Add a helper for accessing CLOCK_TAI for time sensitive network
related programs.
- Support accessing network tunnel metadata's flags.
- Make TCP SYN ACK RTO tunable by BPF programs with TCP Fast Open.
- Add support for writing to Netfilter's nf_conn:mark.
Protocols
---------
- WiFi: more Extremely High Throughput (EHT) and Multi-Link
Operation (MLO) work (802.11be, WiFi 7).
- vsock: improve support for SO_RCVLOWAT.
- SMC: support SO_REUSEPORT.
- Netlink: define and document how to use netlink in a "modern" way.
Support reporting missing attributes via extended ACK.
- IPSec: support collect metadata mode for xfrm interfaces.
- TCPv6: send consistent autoflowlabel in SYN_RECV state
and RST packets.
- TCP: introduce optional per-netns connection hash table to allow
better isolation between namespaces (opt-in, at the cost of memory
and cache pressure).
- MPTCP: support TCP_FASTOPEN_CONNECT.
- Add NEXT-C-SID support in Segment Routing (SRv6) End behavior.
- Adjust IP_UNICAST_IF sockopt behavior for connected UDP sockets.
- Open vSwitch:
- Allow specifying ifindex of new interfaces.
- Allow conntrack and metering in non-initial user namespace.
- TLS: support the Korean ARIA-GCM crypto algorithm.
- Remove DECnet support.
Driver API
----------
- Allow selecting the conduit interface used by each port
in DSA switches, at runtime.
- Ethernet Power Sourcing Equipment and Power Device support.
- Add tc-taprio support for queueMaxSDU parameter, i.e. setting
per traffic class max frame size for time-based packet schedules.
- Support PHY rate matching - adapting between differing host-side
and link-side speeds.
- Introduce QUSGMII PHY mode and 1000BASE-KX interface mode.
- Validate OF (device tree) nodes for DSA shared ports; make
phylink-related properties mandatory on DSA and CPU ports.
Enforcing more uniformity should allow transitioning to phylink.
- Require that flash component name used during update matches one
of the components for which version is reported by info_get().
- Remove "weight" argument from driver-facing NAPI API as much
as possible. It's one of those magic knobs which seemed like
a good idea at the time but is too indirect to use in practice.
- Support offload of TLS connections with 256 bit keys.
New hardware / drivers
----------------------
- Ethernet:
- Microchip KSZ9896 6-port Gigabit Ethernet Switch
- Renesas Ethernet AVB (EtherAVB-IF) Gen4 SoCs
- Analog Devices ADIN1110 and ADIN2111 industrial single pair
Ethernet (10BASE-T1L) MAC+PHY.
- Rockchip RV1126 Gigabit Ethernet (a version of stmmac IP).
- Ethernet SFPs / modules:
- RollBall / Hilink / Turris 10G copper SFPs
- HALNy GPON module
- WiFi:
- CYW43439 SDIO chipset (brcmfmac)
- CYW89459 PCIe chipset (brcmfmac)
- BCM4378 on Apple platforms (brcmfmac)
Drivers
-------
- CAN:
- gs_usb: HW timestamp support
- Ethernet PHYs:
- lan8814: cable diagnostics
- Ethernet NICs:
- Intel (100G):
- implement control of FCS/CRC stripping
- port splitting via devlink
- L2TPv3 filtering offload
- nVidia/Mellanox:
- tunnel offload for sub-functions
- MACSec offload, w/ Extended packet number and replay
window offload
- significantly restructure, and optimize the AF_XDP support,
align the behavior with other vendors
- Huawei:
- configuring DSCP map for traffic class selection
- querying standard FEC statistics
- querying SerDes lane number via ethtool
- Marvell/Cavium:
- egress priority flow control
- MACSec offload
- AMD/SolarFlare:
- PTP over IPv6 and raw Ethernet
- small / embedded:
- ax88772: convert to phylink (to support SFP cages)
- altera: tse: convert to phylink
- ftgmac100: support fixed link
- enetc: standard Ethtool counters
- macb: ZynqMP SGMII dynamic configuration support
- tsnep: support multi-queue and use page pool
- lan743x: Rx IP & TCP checksum offload
- igc: add xdp frags support to ndo_xdp_xmit
- Ethernet high-speed switches:
- Marvell (prestera):
- support SPAN port features (traffic mirroring)
- nexthop object offloading
- Microchip (sparx5):
- multicast forwarding offload
- QoS queuing offload (tc-mqprio, tc-tbf, tc-ets)
- Ethernet embedded switches:
- Marvell (mv88e6xxx):
- support RGMII cmode
- NXP (felix):
- standardized ethtool counters
- Microchip (lan966x):
- QoS queuing offload (tc-mqprio, tc-tbf, tc-cbs, tc-ets)
- traffic policing and mirroring
- link aggregation / bonding offload
- QUSGMII PHY mode support
- Qualcomm 802.11ax WiFi (ath11k):
- cold boot calibration support on WCN6750
- support to connect to a non-transmit MBSSID AP profile
- enable remain-on-channel support on WCN6750
- Wake-on-WLAN support for WCN6750
- support to provide transmit power from firmware via nl80211
- support to get power save duration for each client
- spectral scan support for 160 MHz
- MediaTek WiFi (mt76):
- WiFi-to-Ethernet bridging offload for MT7986 chips
- RealTek WiFi (rtw89):
- P2P support
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'net-next-6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
Pull networking updates from Jakub Kicinski:
"Core:
- Introduce and use a single page frag cache for allocating small skb
heads, clawing back the 10-20% performance regression in UDP flood
test from previous fixes.
- Run packets which already went thru HW coalescing thru SW GRO. This
significantly improves TCP segment coalescing and simplifies
deployments as different workloads benefit from HW or SW GRO.
- Shrink the size of the base zero-copy send structure.
- Move TCP init under a new slow / sleepable version of DO_ONCE().
BPF:
- Add BPF-specific, any-context-safe memory allocator.
- Add helpers/kfuncs for PKCS#7 signature verification from BPF
programs.
- Define a new map type and related helpers for user space -> kernel
communication over a ring buffer (BPF_MAP_TYPE_USER_RINGBUF).
- Allow targeting BPF iterators to loop through resources of one
task/thread.
- Add ability to call selected destructive functions. Expose
crash_kexec() to allow BPF to trigger a kernel dump. Use
CAP_SYS_BOOT check on the loading process to judge permissions.
- Enable BPF to collect custom hierarchical cgroup stats efficiently
by integrating with the rstat framework.
- Support struct arguments for trampoline based programs. Only
structs with size <= 16B and x86 are supported.
- Invoke cgroup/connect{4,6} programs for unprivileged ICMP ping
sockets (instead of just TCP and UDP sockets).
- Add a helper for accessing CLOCK_TAI for time sensitive network
related programs.
- Support accessing network tunnel metadata's flags.
- Make TCP SYN ACK RTO tunable by BPF programs with TCP Fast Open.
- Add support for writing to Netfilter's nf_conn:mark.
Protocols:
- WiFi: more Extremely High Throughput (EHT) and Multi-Link Operation
(MLO) work (802.11be, WiFi 7).
- vsock: improve support for SO_RCVLOWAT.
- SMC: support SO_REUSEPORT.
- Netlink: define and document how to use netlink in a "modern" way.
Support reporting missing attributes via extended ACK.
- IPSec: support collect metadata mode for xfrm interfaces.
- TCPv6: send consistent autoflowlabel in SYN_RECV state and RST
packets.
- TCP: introduce optional per-netns connection hash table to allow
better isolation between namespaces (opt-in, at the cost of memory
and cache pressure).
- MPTCP: support TCP_FASTOPEN_CONNECT.
- Add NEXT-C-SID support in Segment Routing (SRv6) End behavior.
- Adjust IP_UNICAST_IF sockopt behavior for connected UDP sockets.
- Open vSwitch:
- Allow specifying ifindex of new interfaces.
- Allow conntrack and metering in non-initial user namespace.
- TLS: support the Korean ARIA-GCM crypto algorithm.
- Remove DECnet support.
Driver API:
- Allow selecting the conduit interface used by each port in DSA
switches, at runtime.
- Ethernet Power Sourcing Equipment and Power Device support.
- Add tc-taprio support for queueMaxSDU parameter, i.e. setting per
traffic class max frame size for time-based packet schedules.
- Support PHY rate matching - adapting between differing host-side
and link-side speeds.
- Introduce QUSGMII PHY mode and 1000BASE-KX interface mode.
- Validate OF (device tree) nodes for DSA shared ports; make
phylink-related properties mandatory on DSA and CPU ports.
Enforcing more uniformity should allow transitioning to phylink.
- Require that flash component name used during update matches one of
the components for which version is reported by info_get().
- Remove "weight" argument from driver-facing NAPI API as much as
possible. It's one of those magic knobs which seemed like a good
idea at the time but is too indirect to use in practice.
- Support offload of TLS connections with 256 bit keys.
New hardware / drivers:
- Ethernet:
- Microchip KSZ9896 6-port Gigabit Ethernet Switch
- Renesas Ethernet AVB (EtherAVB-IF) Gen4 SoCs
- Analog Devices ADIN1110 and ADIN2111 industrial single pair
Ethernet (10BASE-T1L) MAC+PHY.
- Rockchip RV1126 Gigabit Ethernet (a version of stmmac IP).
- Ethernet SFPs / modules:
- RollBall / Hilink / Turris 10G copper SFPs
- HALNy GPON module
- WiFi:
- CYW43439 SDIO chipset (brcmfmac)
- CYW89459 PCIe chipset (brcmfmac)
- BCM4378 on Apple platforms (brcmfmac)
Drivers:
- CAN:
- gs_usb: HW timestamp support
- Ethernet PHYs:
- lan8814: cable diagnostics
- Ethernet NICs:
- Intel (100G):
- implement control of FCS/CRC stripping
- port splitting via devlink
- L2TPv3 filtering offload
- nVidia/Mellanox:
- tunnel offload for sub-functions
- MACSec offload, w/ Extended packet number and replay window
offload
- significantly restructure, and optimize the AF_XDP support,
align the behavior with other vendors
- Huawei:
- configuring DSCP map for traffic class selection
- querying standard FEC statistics
- querying SerDes lane number via ethtool
- Marvell/Cavium:
- egress priority flow control
- MACSec offload
- AMD/SolarFlare:
- PTP over IPv6 and raw Ethernet
- small / embedded:
- ax88772: convert to phylink (to support SFP cages)
- altera: tse: convert to phylink
- ftgmac100: support fixed link
- enetc: standard Ethtool counters
- macb: ZynqMP SGMII dynamic configuration support
- tsnep: support multi-queue and use page pool
- lan743x: Rx IP & TCP checksum offload
- igc: add xdp frags support to ndo_xdp_xmit
- Ethernet high-speed switches:
- Marvell (prestera):
- support SPAN port features (traffic mirroring)
- nexthop object offloading
- Microchip (sparx5):
- multicast forwarding offload
- QoS queuing offload (tc-mqprio, tc-tbf, tc-ets)
- Ethernet embedded switches:
- Marvell (mv88e6xxx):
- support RGMII cmode
- NXP (felix):
- standardized ethtool counters
- Microchip (lan966x):
- QoS queuing offload (tc-mqprio, tc-tbf, tc-cbs, tc-ets)
- traffic policing and mirroring
- link aggregation / bonding offload
- QUSGMII PHY mode support
- Qualcomm 802.11ax WiFi (ath11k):
- cold boot calibration support on WCN6750
- support to connect to a non-transmit MBSSID AP profile
- enable remain-on-channel support on WCN6750
- Wake-on-WLAN support for WCN6750
- support to provide transmit power from firmware via nl80211
- support to get power save duration for each client
- spectral scan support for 160 MHz
- MediaTek WiFi (mt76):
- WiFi-to-Ethernet bridging offload for MT7986 chips
- RealTek WiFi (rtw89):
- P2P support"
* tag 'net-next-6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1864 commits)
eth: pse: add missing static inlines
once: rename _SLOW to _SLEEPABLE
net: pse-pd: add regulator based PSE driver
dt-bindings: net: pse-dt: add bindings for regulator based PoDL PSE controller
ethtool: add interface to interact with Ethernet Power Equipment
net: mdiobus: search for PSE nodes by parsing PHY nodes.
net: mdiobus: fwnode_mdiobus_register_phy() rework error handling
net: add framework to support Ethernet PSE and PDs devices
dt-bindings: net: phy: add PoDL PSE property
net: marvell: prestera: Propagate nh state from hw to kernel
net: marvell: prestera: Add neighbour cache accounting
net: marvell: prestera: add stub handler neighbour events
net: marvell: prestera: Add heplers to interact with fib_notifier_info
net: marvell: prestera: Add length macros for prestera_ip_addr
net: marvell: prestera: add delayed wq and flush wq on deinit
net: marvell: prestera: Add strict cleanup of fib arbiter
net: marvell: prestera: Add cleanup of allocated fib_nodes
net: marvell: prestera: Add router nexthops ABI
eth: octeon: fix build after netif_napi_add() changes
net/mlx5: E-Switch, Return EBUSY if can't get mode lock
...
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Merge tag 'lsm-pr-20221003' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm
Pull LSM updates from Paul Moore:
"Seven patches for the LSM layer and we've got a mix of trivial and
significant patches. Highlights below, starting with the smaller bits
first so they don't get lost in the discussion of the larger items:
- Remove some redundant NULL pointer checks in the common LSM audit
code.
- Ratelimit the lockdown LSM's access denial messages.
With this change there is a chance that the last visible lockdown
message on the console is outdated/old, but it does help preserve
the initial series of lockdown denials that started the denial
message flood and my gut feeling is that these might be the more
valuable messages.
- Open userfaultfds as readonly instead of read/write.
While this code obviously lives outside the LSM, it does have a
noticeable impact on the LSMs with Ondrej explaining the situation
in the commit description. It is worth noting that this patch
languished on the VFS list for over a year without any comments
(objections or otherwise) so I took the liberty of pulling it into
the LSM tree after giving fair notice. It has been in linux-next
since the end of August without any noticeable problems.
- Add a LSM hook for user namespace creation, with implementations
for both the BPF LSM and SELinux.
Even though the changes are fairly small, this is the bulk of the
diffstat as we are also including BPF LSM selftests for the new
hook.
It's also the most contentious of the changes in this pull request
with Eric Biederman NACK'ing the LSM hook multiple times during its
development and discussion upstream. While I've never taken NACK's
lightly, I'm sending these patches to you because it is my belief
that they are of good quality, satisfy a long-standing need of
users and distros, and are in keeping with the existing nature of
the LSM layer and the Linux Kernel as a whole.
The patches in implement a LSM hook for user namespace creation
that allows for a granular approach, configurable at runtime, which
enables both monitoring and control of user namespaces. The general
consensus has been that this is far preferable to the other
solutions that have been adopted downstream including outright
removal from the kernel, disabling via system wide sysctls, or
various other out-of-tree mechanisms that users have been forced to
adopt since we haven't been able to provide them an upstream
solution for their requests. Eric has been steadfast in his
objections to this LSM hook, explaining that any restrictions on
the user namespace could have significant impact on userspace.
While there is the possibility of impacting userspace, it is
important to note that this solution only impacts userspace when it
is requested based on the runtime configuration supplied by the
distro/admin/user. Frederick (the pathset author), the LSM/security
community, and myself have tried to work with Eric during
development of this patchset to find a mutually acceptable
solution, but Eric's approach and unwillingness to engage in a
meaningful way have made this impossible. I have CC'd Eric directly
on this pull request so he has a chance to provide his side of the
story; there have been no objections outside of Eric's"
* tag 'lsm-pr-20221003' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm:
lockdown: ratelimit denial messages
userfaultfd: open userfaultfds with O_RDONLY
selinux: Implement userns_create hook
selftests/bpf: Add tests verifying bpf lsm userns_create hook
bpf-lsm: Make bpf_lsm_userns_create() sleepable
security, lsm: Introduce security_create_user_ns()
lsm: clean up redundant NULL pointer check
When executing BPF programs, certain registers may get passed
uninitialized to helper functions. E.g. when performing a JMP_CALL,
registers BPF_R1-BPF_R5 are always passed to the helper, no matter how
many of them are actually used.
Passing uninitialized values as function parameters is technically
undefined behavior, so we work around it by always initializing the
registers.
Link: https://lkml.kernel.org/r/20220915150417.722975-42-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Marco Elver <elver@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The struct_ops prog is to allow using bpf to implement the functions in
a struct (eg. kernel module). The current usage is to implement the
tcp_congestion. The kernel does not call the tcp-cc's ops (ie.
the bpf prog) in a recursive way.
The struct_ops is sharing the tracing-trampoline's enter/exit
function which tracks prog->active to avoid recursion. It is
needed for tracing prog. However, it turns out the struct_ops
bpf prog will hit this prog->active and unnecessarily skipped
running the struct_ops prog. eg. The '.ssthresh' may run in_task()
and then interrupted by softirq that runs the same '.ssthresh'.
Skip running the '.ssthresh' will end up returning random value
to the caller.
The patch adds __bpf_prog_{enter,exit}_struct_ops for the
struct_ops trampoline. They do not track the prog->active
to detect recursion.
One exception is when the tcp_congestion's '.init' ops is doing
bpf_setsockopt(TCP_CONGESTION) and then recurs to the same
'.init' ops. This will be addressed in the following patches.
Fixes: ca06f55b90 ("bpf: Add per-program recursion prevention mechanism")
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220929070407.965581-2-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Show information of iterators in the respective files under
/proc/<pid>/fdinfo/.
For example, for a task file iterator with 1723 as the value of tid
parameter, its fdinfo would look like the following lines.
pos: 0
flags: 02000000
mnt_id: 14
ino: 38
link_type: iter
link_id: 51
prog_tag: a590ac96db22b825
prog_id: 299
target_name: task_file
task_type: TID
tid: 1723
This patch add the last three fields. task_type is the type of the
task parameter. TID means the iterator visit only the thread
specified by tid. The value of tid in the above example is 1723. For
the case of PID task_type, it means the iterator visits only threads
of a process and will show the pid value of the process instead of a
tid.
Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/bpf/20220926184957.208194-4-kuifeng@fb.com
Add new fields to bpf_link_info that users can query it through
bpf_obj_get_info_by_fd().
Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/bpf/20220926184957.208194-3-kuifeng@fb.com
Allow creating an iterator that loops through resources of one
thread/process.
People could only create iterators to loop through all resources of
files, vma, and tasks in the system, even though they were interested
in only the resources of a specific task or process. Passing the
additional parameters, people can now create an iterator to go
through all resources or only the resources of a task.
Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/bpf/20220926184957.208194-2-kuifeng@fb.com
Mark the trampoline as RO+X after arch_prepare_bpf_trampoline, so that
the trampoine follows W^X rule strictly. This will turn off warnings like
CPA refuse W^X violation: 8000000000000163 -> 0000000000000163 range: ...
Also remove bpf_jit_alloc_exec_page(), since it is not used any more.
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20220926184739.3512547-3-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Allocate bpf_dispatcher with bpf_prog_pack_alloc so that bpf_dispatcher
can share pages with bpf programs.
arch_prepare_bpf_dispatcher() is updated to provide a RW buffer as working
area for arch code to write to.
This also fixes CPA W^X warnning like:
CPA refuse W^X violation: 8000000000000163 -> 0000000000000163 range: ...
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20220926184739.3512547-2-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Use vma_next() and remove reference to the start of the linked list
Link: https://lkml.kernel.org/r/20220906194824.2110408-51-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Instead of forcing all arguments to be referenced pointers with non-zero
reg->ref_obj_id, tweak the definition of KF_TRUSTED_ARGS to mean that
only PTR_TO_BTF_ID (and socket types translated to PTR_TO_BTF_ID) have
that constraint, and require their offset to be set to 0.
The rest of pointer types are also accomodated in this definition of
trusted pointers, but with more relaxed rules regarding offsets.
The inherent meaning of setting this flag is that all kfunc pointer
arguments have a guranteed lifetime, and kernel object pointers
(PTR_TO_BTF_ID, PTR_TO_CTX) are passed in their unmodified form (with
offset 0). In general, this is not true for PTR_TO_BTF_ID as it can be
obtained using pointer walks.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/cdede0043c47ed7a357f0a915d16f9ce06a1d589.1663778601.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
For a non-preallocated hash map on RT kernel, regular spinlock instead
of raw spinlock is used for bucket lock. The reason is that on RT kernel
memory allocation is forbidden under atomic context and regular spinlock
is sleepable under RT.
Now hash map has been fully converted to use bpf_map_alloc, and there
will be no synchronous memory allocation for non-preallocated hash map,
so it is safe to always use raw spinlock for bucket lock on RT. So
removing the usage of htab_use_raw_lock() and updating the comments
accordingly.
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20220921073826.2365800-1-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
We got report from sysbot [1] about warnings that were caused by
bpf program attached to contention_begin raw tracepoint triggering
the same tracepoint by using bpf_trace_printk helper that takes
trace_printk_lock lock.
Call Trace:
<TASK>
? trace_event_raw_event_bpf_trace_printk+0x5f/0x90
bpf_trace_printk+0x2b/0xe0
bpf_prog_a9aec6167c091eef_prog+0x1f/0x24
bpf_trace_run2+0x26/0x90
native_queued_spin_lock_slowpath+0x1c6/0x2b0
_raw_spin_lock_irqsave+0x44/0x50
bpf_trace_printk+0x3f/0xe0
bpf_prog_a9aec6167c091eef_prog+0x1f/0x24
bpf_trace_run2+0x26/0x90
native_queued_spin_lock_slowpath+0x1c6/0x2b0
_raw_spin_lock_irqsave+0x44/0x50
bpf_trace_printk+0x3f/0xe0
bpf_prog_a9aec6167c091eef_prog+0x1f/0x24
bpf_trace_run2+0x26/0x90
native_queued_spin_lock_slowpath+0x1c6/0x2b0
_raw_spin_lock_irqsave+0x44/0x50
bpf_trace_printk+0x3f/0xe0
bpf_prog_a9aec6167c091eef_prog+0x1f/0x24
bpf_trace_run2+0x26/0x90
native_queued_spin_lock_slowpath+0x1c6/0x2b0
_raw_spin_lock_irqsave+0x44/0x50
__unfreeze_partials+0x5b/0x160
...
The can be reproduced by attaching bpf program as raw tracepoint on
contention_begin tracepoint. The bpf prog calls bpf_trace_printk
helper. Then by running perf bench the spin lock code is forced to
take slow path and call contention_begin tracepoint.
Fixing this by skipping execution of the bpf program if it's
already running, Using bpf prog 'active' field, which is being
currently used by trampoline programs for the same reason.
Moving bpf_prog_inc_misses_counter to syscall.c because
trampoline.c is compiled in just for CONFIG_BPF_JIT option.
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Reported-by: syzbot+2251879aa068ad9c960d@syzkaller.appspotmail.com
[1] https://lore.kernel.org/bpf/YxhFe3EwqchC%2FfYf@krava/T/#t
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220916071914.7156-1-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Export bpf_dynptr_get_size(), so that kernel code dealing with eBPF dynamic
pointers can obtain the real size of data carried by this data structure.
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: Joanne Koong <joannelkoong@gmail.com>
Acked-by: KP Singh <kpsingh@kernel.org>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220920075951.929132-6-roberto.sassu@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Allow dynamic pointers (struct bpf_dynptr_kern *) to be specified as
parameters in kfuncs. Also, ensure that dynamic pointers passed as argument
are valid and initialized, are a pointer to the stack, and of the type
local. More dynamic pointer types can be supported in the future.
To properly detect whether a parameter is of the desired type, introduce
the stringify_struct() macro to compare the returned structure name with
the desired name. In addition, protect against structure renames, by
halting the build with BUILD_BUG_ON(), so that developers have to revisit
the code.
To check if a dynamic pointer passed to the kfunc is valid and initialized,
and if its type is local, export the existing functions
is_dynptr_reg_valid_init() and is_dynptr_type_expected().
Cc: Joanne Koong <joannelkoong@gmail.com>
Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220920075951.929132-5-roberto.sassu@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Move dynptr type check to is_dynptr_type_expected() from
is_dynptr_reg_valid_init(), so that callers can better determine the cause
of a negative result (dynamic pointer not valid/initialized, dynamic
pointer of the wrong type). It will be useful for example for BTF, to
restrict which dynamic pointer types can be passed to kfuncs, as initially
only the local type will be supported.
Also, splitting makes the code more readable, since checking the dynamic
pointer type is not necessarily related to validity and initialization.
Split the validity/initialization and dynamic pointer type check also in
the verifier, and adjust the expected error message in the test (a test for
an unexpected dynptr type passed to a helper cannot be added due to missing
suitable helpers, but this case has been tested manually).
Cc: Joanne Koong <joannelkoong@gmail.com>
Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220920075951.929132-4-roberto.sassu@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
eBPF dynamic pointers is a new feature recently added to upstream. It binds
together a pointer to a memory area and its size. The internal kernel
structure bpf_dynptr_kern is not accessible by eBPF programs in user space.
They instead see bpf_dynptr, which is then translated to the internal
kernel structure by the eBPF verifier.
The problem is that it is not possible to include at the same time the uapi
include linux/bpf.h and the vmlinux BTF vmlinux.h, as they both contain the
definition of some structures/enums. The compiler complains saying that the
structures/enums are redefined.
As bpf_dynptr is defined in the uapi include linux/bpf.h, this makes it
impossible to include vmlinux.h. However, in some cases, e.g. when using
kfuncs, vmlinux.h has to be included. The only option until now was to
include vmlinux.h and add the definition of bpf_dynptr directly in the eBPF
program source code from linux/bpf.h.
Solve the problem by using the same approach as for bpf_timer (which also
follows the same scheme with the _kern suffix for the internal kernel
structure).
Add the following line in one of the dynamic pointer helpers,
bpf_dynptr_from_mem():
BTF_TYPE_EMIT(struct bpf_dynptr);
Cc: stable@vger.kernel.org
Cc: Joanne Koong <joannelkoong@gmail.com>
Fixes: 97e03f5210 ("bpf: Add verifier support for dynptrs")
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: Yonghong Song <yhs@fb.com>
Tested-by: KP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/r/20220920075951.929132-3-roberto.sassu@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In preparation for the addition of new kfuncs, allow kfuncs defined in the
tracing subsystem to be used in LSM programs by mapping the LSM program
type to the TRACING hook.
Signed-off-by: KP Singh <kpsingh@kernel.org>
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220920075951.929132-2-roberto.sassu@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In a prior change, we added a new BPF_MAP_TYPE_USER_RINGBUF map type which
will allow user-space applications to publish messages to a ring buffer
that is consumed by a BPF program in kernel-space. In order for this
map-type to be useful, it will require a BPF helper function that BPF
programs can invoke to drain samples from the ring buffer, and invoke
callbacks on those samples. This change adds that capability via a new BPF
helper function:
bpf_user_ringbuf_drain(struct bpf_map *map, void *callback_fn, void *ctx,
u64 flags)
BPF programs may invoke this function to run callback_fn() on a series of
samples in the ring buffer. callback_fn() has the following signature:
long callback_fn(struct bpf_dynptr *dynptr, void *context);
Samples are provided to the callback in the form of struct bpf_dynptr *'s,
which the program can read using BPF helper functions for querying
struct bpf_dynptr's.
In order to support bpf_ringbuf_drain(), a new PTR_TO_DYNPTR register
type is added to the verifier to reflect a dynptr that was allocated by
a helper function and passed to a BPF program. Unlike PTR_TO_STACK
dynptrs which are allocated on the stack by a BPF program, PTR_TO_DYNPTR
dynptrs need not use reference tracking, as the BPF helper is trusted to
properly free the dynptr before returning. The verifier currently only
supports PTR_TO_DYNPTR registers that are also DYNPTR_TYPE_LOCAL.
Note that while the corresponding user-space libbpf logic will be added
in a subsequent patch, this patch does contain an implementation of the
.map_poll() callback for BPF_MAP_TYPE_USER_RINGBUF maps. This
.map_poll() callback guarantees that an epoll-waiting user-space
producer will receive at least one event notification whenever at least
one sample is drained in an invocation of bpf_user_ringbuf_drain(),
provided that the function is not invoked with the BPF_RB_NO_WAKEUP
flag. If the BPF_RB_FORCE_WAKEUP flag is provided, a wakeup
notification is sent even if no sample was drained.
Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220920000100.477320-3-void@manifault.com
We want to support a ringbuf map type where samples are published from
user-space, to be consumed by BPF programs. BPF currently supports a
kernel -> user-space circular ring buffer via the BPF_MAP_TYPE_RINGBUF
map type. We'll need to define a new map type for user-space -> kernel,
as none of the helpers exported for BPF_MAP_TYPE_RINGBUF will apply
to a user-space producer ring buffer, and we'll want to add one or
more helper functions that would not apply for a kernel-producer
ring buffer.
This patch therefore adds a new BPF_MAP_TYPE_USER_RINGBUF map type
definition. The map type is useless in its current form, as there is no
way to access or use it for anything until we one or more BPF helpers. A
follow-on patch will therefore add a new helper function that allows BPF
programs to run callbacks on samples that are published to the ring
buffer.
Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220920000100.477320-2-void@manifault.com
This has been enabled for unprivileged programs for only one kernel
release, hence the expected annoyances due to this move are low. Users
using ringbuf can stick to non-dynptr APIs. The actual use cases dynptr
is meant to serve may not make sense in unprivileged BPF programs.
Hence, gate these helpers behind CAP_BPF and limit use to privileged
BPF programs.
Fixes: 263ae152e9 ("bpf: Add bpf_dynptr_from_mem for local dynptrs")
Fixes: bc34dee65a ("bpf: Dynptr support for ring buffers")
Fixes: 13bbbfbea7 ("bpf: Add bpf_dynptr_read and bpf_dynptr_write")
Fixes: 34d4ef5775 ("bpf: Add dynptr data slices")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220921143550.30247-1-memxor@gmail.com
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Attach flags is only valid for attached progs of this layer cgroup,
but not for effective progs. For querying with EFFECTIVE flags,
exporting attach flags does not make sense. So when effective query,
we reject prog_attach_flags array and don't need to populate it.
Also we limit attach_flags to output 0 during effective query.
Fixes: b79c9fc955 ("bpf: implement BPF_PROG_QUERY for BPF_LSM_CGROUP")
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Link: https://lore.kernel.org/r/20220921104604.2340580-2-pulehui@huaweicloud.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
It could directly return 'btf_check_sec_info' to simplify code.
Signed-off-by: William Dean <williamsukatube@163.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220917084248.3649-1-williamsukatube@163.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
llnode could be NULL if there are new allocations after the checking of
c-free_cnt > c->high_watermark in bpf_mem_refill() and before the
calling of __llist_del_first() in free_bulk (e.g. a PREEMPT_RT kernel
or allocation in NMI context). And it will incur oops as shown below:
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 0 P4D 0
Oops: 0002 [#1] PREEMPT_RT SMP
CPU: 39 PID: 373 Comm: irq_work/39 Tainted: G W 6.0.0-rc6-rt9+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
RIP: 0010:bpf_mem_refill+0x66/0x130
......
Call Trace:
<TASK>
irq_work_single+0x24/0x60
irq_work_run_list+0x24/0x30
run_irq_workd+0x18/0x20
smpboot_thread_fn+0x13f/0x2c0
kthread+0x121/0x140
? kthread_complete_and_exit+0x20/0x20
ret_from_fork+0x1f/0x30
</TASK>
Simply fixing it by checking whether or not llnode is NULL in free_bulk().
Fixes: 8d5a8011b3 ("bpf: Batch call_rcu callbacks instead of SLAB_TYPESAFE_BY_RCU.")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20220919144811.3570825-1-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
We have btf_type_str(). Use it whenever possible in btf.c, instead of
"btf_kind_str[BTF_INFO_KIND(t->info)]".
Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>
Link: https://lore.kernel.org/r/20220916202800.31421-1-yepeilin.cs@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
The documentation for find_vpid() clearly states:
"Must be called with the tasklist_lock or rcu_read_lock() held."
Presently we do neither for find_vpid() instance in bpf_task_fd_query().
Add proper rcu_read_lock/unlock() to fix the issue.
Fixes: 41bdc4b40e ("bpf: introduce bpf subcommand BPF_TASK_FD_QUERY")
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220912133855.1218900-1-lee@kernel.org
BPF_PTR_POISON was added in commit c0a5a21c25 ("bpf: Allow storing
referenced kptr in map") to denote a bpf_func_proto btf_id which the
verifier will replace with a dynamically-determined btf_id at verification
time.
This patch adds verifier 'poison' functionality to BPF_PTR_POISON in
order to prepare for expanded use of the value to poison ret- and
arg-btf_id in ongoing work, namely rbtree and linked list patchsets
[0, 1]. Specifically, when the verifier checks helper calls, it assumes
that BPF_PTR_POISON'ed ret type will be replaced with a valid type before
- or in lieu of - the default ret_btf_id logic. Similarly for arg btf_id.
If poisoned btf_id reaches default handling block for either, consider
this a verifier internal error and fail verification. Otherwise a helper
w/ poisoned btf_id but no verifier logic replacing the type will cause a
crash as the invalid pointer is dereferenced.
Also move BPF_PTR_POISON to existing include/linux/posion.h header and
remove unnecessary shift.
[0]: lore.kernel.org/bpf/20220830172759.4069786-1-davemarchevsky@fb.com
[1]: lore.kernel.org/bpf/20220904204145.3089-1-memxor@gmail.com
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220912154544.1398199-1-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
If the perf_event has PERF_SAMPLE_CALLCHAIN, BPF can use it for stack trace.
The problematic cases like PEBS and IBS already handled in the PMU driver and
they filled the callchain info in the sample data. For others, we can call
perf_callchain() before the BPF handler.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220908214104.3851807-2-namhyung@kernel.org
Verifier logic to confirm that a callback function returns 0 or 1 was
added in commit 69c087ba62 ("bpf: Add bpf_for_each_map_elem() helper").
At the time, callback return value was only used to continue or stop
iteration.
In order to support callbacks with a broader return value range, such as
those added in rbtree series[0] and others, add a callback_ret_range to
bpf_func_state. Verifier's helpers which set in_callback_fn will also
set the new field, which the verifier will later use to check return
value bounds.
Default to tnum_range(0, 0) instead of using tnum_unknown as a sentinel
value as the latter would prevent the valid range (0, U64_MAX) being
used. Previous global default tnum_range(0, 1) is explicitly set for
extant callback helpers. The change to global default was made after
discussion around this patch in rbtree series [1], goal here is to make
it more obvious that callback_ret_range should be explicitly set.
[0]: lore.kernel.org/bpf/20220830172759.4069786-1-davemarchevsky@fb.com/
[1]: lore.kernel.org/bpf/20220830172759.4069786-2-davemarchevsky@fb.com/
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20220908230716.2751723-1-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When trying to finish resolving a struct member, btf_struct_resolve
saves the member type id in a u16 temporary variable. This truncates
the 32 bit type id value if it exceeds UINT16_MAX.
As a result, structs that have members with type ids > UINT16_MAX and
which need resolution will fail with a message like this:
[67414] STRUCT ff_device size=120 vlen=12
effect_owners type_id=67434 bits_offset=960 Member exceeds struct_size
Fix this by changing the type of last_member_type_id to u32.
Fixes: a0791f0df7 ("bpf: fix BTF limits")
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Lorenz Bauer <oss@lmb.io>
Link: https://lore.kernel.org/r/20220910110120.339242-1-oss@lmb.io
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Since commit 27ae7997a6 ("bpf: Introduce BPF_PROG_TYPE_STRUCT_OPS")
there has existed bpf_verifier_ops:btf_struct_access. When
btf_struct_access is _unset_ for a prog type, the verifier runs the
default implementation, which is to enforce read only:
if (env->ops->btf_struct_access) {
[...]
} else {
if (atype != BPF_READ) {
verbose(env, "only read is supported\n");
return -EACCES;
}
[...]
}
When btf_struct_access is _set_, the expectation is that
btf_struct_access has full control over accesses, including if writes
are allowed.
Rather than carve out an exception for each prog type that may write to
BTF ptrs, delete the redundant check and give full control to
btf_struct_access.
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/962da2bff1238746589e332ff1aecc49403cd7ce.1662568410.git.dxu@dxuuu.xyz
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In the percpu freelist code, it is a common pattern to iterate over
the possible CPUs mask starting with the current CPU. The pattern is
implemented using a hand rolled while loop with the loop variable
increment being open-coded.
Simplify the code by using for_each_cpu_wrap() helper to iterate over
the possible cpus starting with the current CPU. As a result, some of
the special-casing in the loop also gets simplified.
No functional change intended.
Signed-off-by: Punit Agrawal <punit.agrawal@bytedance.com>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20220907155746.1750329-1-punit.agrawal@bytedance.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
syzbot is reporting ODEBUG bug in htab_map_alloc() [1], for
commit 86fe28f769 ("bpf: Optimize element count in non-preallocated
hash map.") added percpu_counter_init() to htab_map_alloc() but forgot to
add percpu_counter_destroy() to the error path.
Link: https://syzkaller.appspot.com/bug?extid=5d1da78b375c3b5e6c2b [1]
Reported-by: syzbot <syzbot+5d1da78b375c3b5e6c2b@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Fixes: 86fe28f769 ("bpf: Optimize element count in non-preallocated hash map.")
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/e2e4cc0e-9d36-4ca1-9bfa-ce23e6f8310b@I-love.SAKURA.ne.jp
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
For a lot of use cases in future patches, we will want to modify the
state of registers part of some same 'group' (e.g. same ref_obj_id). It
won't just be limited to releasing reference state, but setting a type
flag dynamically based on certain actions, etc.
Hence, we need a way to easily pass a callback to the function that
iterates over all registers in current bpf_verifier_state in all frames
upto (and including) the curframe.
While in C++ we would be able to easily use a lambda to pass state and
the callback together, sadly we aren't using C++ in the kernel. The next
best thing to avoid defining a function for each case seems like
statement expressions in GNU C. The kernel already uses them heavily,
hence they can passed to the macro in the style of a lambda. The
statement expression will then be substituted in the for loop bodies.
Variables __state and __reg are set to current bpf_func_state and reg
for each invocation of the expression inside the passed in verifier
state.
Then, convert mark_ptr_or_null_regs, clear_all_pkt_pointers,
release_reference, find_good_pkt_pointers, find_equal_scalars to
use bpf_for_each_reg_in_vstate.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220904204145.3089-16-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Enable support for kptrs in percpu BPF arraymap by wiring up the freeing
of these kptrs from percpu map elements.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220904204145.3089-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Sparse reported a warning at bpf_map_free_kptrs()
"warning: Using plain integer as NULL pointer"
During the process of fixing this warning, it was discovered that the current
code erroneously writes to the pointer variable instead of deferencing and
writing to the actual kptr. Hence, Sparse tool accidentally helped to uncover
this problem. Fix this by doing WRITE_ONCE(*p, 0) instead of WRITE_ONCE(p, 0).
Note that the effect of this bug is that unreferenced kptrs will not be cleared
during check_and_free_fields. It is not a problem if the clearing is not done
during map_free stage, as there is nothing to free for them.
Fixes: 14a324f6a6 ("bpf: Wire up freeing of referenced kptr")
Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Link: https://lore.kernel.org/r/Yxi3pJaK6UDjVJSy@playground
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
For drivers (outside of network), the incoming data is not statically
defined in a struct. Most of the time the data buffer is kzalloc-ed
and thus we can not rely on eBPF and BTF to explore the data.
This commit allows to return an arbitrary memory, previously allocated by
the driver.
An interesting extra point is that the kfunc can mark the exported
memory region as read only or read/write.
So, when a kfunc is not returning a pointer to a struct but to a plain
type, we can consider it is a valid allocated memory assuming that:
- one of the arguments is either called rdonly_buf_size or
rdwr_buf_size
- and this argument is a const from the caller point of view
We can then use this parameter as the size of the allocated memory.
The memory is either read-only or read-write based on the name
of the size parameter.
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20220906151303.2780789-7-benjamin.tissoires@redhat.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
net/bpf/test_run.c is already presenting 20 kfuncs.
net/netfilter/nf_conntrack_bpf.c is also presenting an extra 10 kfuncs.
Given that all the kfuncs are regrouped into one unique set, having
only 2 space left prevent us to add more selftests.
Bump it to 256.
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20220906151303.2780789-6-benjamin.tissoires@redhat.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When a function was trying to access data from context in a syscall eBPF
program, the verifier was rejecting the call unless it was accessing the
first element.
This is because the syscall context is not known at compile time, and
so we need to check this when actually accessing it.
Check for the valid memory access if there is no convert_ctx callback,
and allow such situation to happen.
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20220906151303.2780789-4-benjamin.tissoires@redhat.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
btf_check_subprog_arg_match() was used twice in verifier.c:
- when checking for the type mismatches between a (sub)prog declaration
and BTF
- when checking the call of a subprog to see if the provided arguments
are correct and valid
This is problematic when we check if the first argument of a program
(pointer to ctx) is correctly accessed:
To be able to ensure we access a valid memory in the ctx, the verifier
assumes the pointer to context is not null.
This has the side effect of marking the program accessing the entire
context, even if the context is never dereferenced.
For example, by checking the context access with the current code, the
following eBPF program would fail with -EINVAL if the ctx is set to null
from the userspace:
```
SEC("syscall")
int prog(struct my_ctx *args) {
return 0;
}
```
In that particular case, we do not want to actually check that the memory
is correct while checking for the BTF validity, but we just want to
ensure that the (sub)prog definition matches the BTF we have.
So split btf_check_subprog_arg_match() in two so we can actually check
for the memory used when in a call, and ignore that part when not.
Note that a further patch is in preparation to disentangled
btf_check_func_arg_match() from these two purposes, and so right now we
just add a new hack around that by adding a boolean to this function.
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220906151303.2780789-3-benjamin.tissoires@redhat.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Allow struct argument in trampoline based programs where
the struct size should be <= 16 bytes. In such cases, the argument
will be put into up to 2 registers for bpf, x86_64 and arm64
architectures.
To support arch-specific trampoline manipulation,
add arg_flags for additional struct information about arguments
in btf_func_model. Such information will be used in arch specific
function arch_prepare_bpf_trampoline() to prepare argument access
properly in trampoline.
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220831152646.2078089-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
__ksize() was made private. Use ksize() instead.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Daniel Borkmann says:
====================
pull-request: bpf-next 2022-09-05
The following pull-request contains BPF updates for your *net-next* tree.
We've added 106 non-merge commits during the last 18 day(s) which contain
a total of 159 files changed, 5225 insertions(+), 1358 deletions(-).
There are two small merge conflicts, resolve them as follows:
1) tools/testing/selftests/bpf/DENYLIST.s390x
Commit 27e23836ce ("selftests/bpf: Add lru_bug to s390x deny list") in
bpf tree was needed to get BPF CI green on s390x, but it conflicted with
newly added tests on bpf-next. Resolve by adding both hunks, result:
[...]
lru_bug # prog 'printk': failed to auto-attach: -524
setget_sockopt # attach unexpected error: -524 (trampoline)
cb_refs # expected error message unexpected error: -524 (trampoline)
cgroup_hierarchical_stats # JIT does not support calling kernel function (kfunc)
htab_update # failed to attach: ERROR: strerror_r(-524)=22 (trampoline)
[...]
2) net/core/filter.c
Commit 1227c1771d ("net: Fix data-races around sysctl_[rw]mem_(max|default).")
from net tree conflicts with commit 29003875bd ("bpf: Change bpf_setsockopt(SOL_SOCKET)
to reuse sk_setsockopt()") from bpf-next tree. Take the code as it is from
bpf-next tree, result:
[...]
if (getopt) {
if (optname == SO_BINDTODEVICE)
return -EINVAL;
return sk_getsockopt(sk, SOL_SOCKET, optname,
KERNEL_SOCKPTR(optval),
KERNEL_SOCKPTR(optlen));
}
return sk_setsockopt(sk, SOL_SOCKET, optname,
KERNEL_SOCKPTR(optval), *optlen);
[...]
The main changes are:
1) Add any-context BPF specific memory allocator which is useful in particular for BPF
tracing with bonus of performance equal to full prealloc, from Alexei Starovoitov.
2) Big batch to remove duplicated code from bpf_{get,set}sockopt() helpers as an effort
to reuse the existing core socket code as much as possible, from Martin KaFai Lau.
3) Extend BPF flow dissector for BPF programs to just augment the in-kernel dissector
with custom logic. In other words, allow for partial replacement, from Shmulik Ladkani.
4) Add a new cgroup iterator to BPF with different traversal options, from Hao Luo.
5) Support for BPF to collect hierarchical cgroup statistics efficiently through BPF
integration with the rstat framework, from Yosry Ahmed.
6) Support bpf_{g,s}et_retval() under more BPF cgroup hooks, from Stanislav Fomichev.
7) BPF hash table and local storages fixes under fully preemptible kernel, from Hou Tao.
8) Add various improvements to BPF selftests and libbpf for compilation with gcc BPF
backend, from James Hilliard.
9) Fix verifier helper permissions and reference state management for synchronous
callbacks, from Kumar Kartikeya Dwivedi.
10) Add support for BPF selftest's xskxceiver to also be used against real devices that
support MAC loopback, from Maciej Fijalkowski.
11) Various fixes to the bpf-helpers(7) man page generation script, from Quentin Monnet.
12) Document BPF verifier's tnum_in(tnum_range(), ...) gotchas, from Shung-Hsi Yu.
13) Various minor misc improvements all over the place.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (106 commits)
bpf: Optimize rcu_barrier usage between hash map and bpf_mem_alloc.
bpf: Remove usage of kmem_cache from bpf_mem_cache.
bpf: Remove prealloc-only restriction for sleepable bpf programs.
bpf: Prepare bpf_mem_alloc to be used by sleepable bpf programs.
bpf: Remove tracing program restriction on map types
bpf: Convert percpu hash map to per-cpu bpf_mem_alloc.
bpf: Add percpu allocation support to bpf_mem_alloc.
bpf: Batch call_rcu callbacks instead of SLAB_TYPESAFE_BY_RCU.
bpf: Adjust low/high watermarks in bpf_mem_cache
bpf: Optimize call_rcu in non-preallocated hash map.
bpf: Optimize element count in non-preallocated hash map.
bpf: Relax the requirement to use preallocated hash maps in tracing progs.
samples/bpf: Reduce syscall overhead in map_perf_test.
selftests/bpf: Improve test coverage of test_maps
bpf: Convert hash map to bpf_mem_alloc.
bpf: Introduce any context BPF specific memory allocator.
selftest/bpf: Add test for bpf_getsockopt()
bpf: Change bpf_getsockopt(SOL_IPV6) to reuse do_ipv6_getsockopt()
bpf: Change bpf_getsockopt(SOL_IP) to reuse do_ip_getsockopt()
bpf: Change bpf_getsockopt(SOL_TCP) to reuse do_tcp_getsockopt()
...
====================
Link: https://lore.kernel.org/r/20220905161136.9150-1-daniel@iogearbox.net
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
User space might be creating and destroying a lot of hash maps. Synchronous
rcu_barrier-s in a destruction path of hash map delay freeing of hash buckets
and other map memory and may cause artificial OOM situation under stress.
Optimize rcu_barrier usage between bpf hash map and bpf_mem_alloc:
- remove rcu_barrier from hash map, since htab doesn't use call_rcu
directly and there are no callback to wait for.
- bpf_mem_alloc has call_rcu_in_progress flag that indicates pending callbacks.
Use it to avoid barriers in fast path.
- When barriers are needed copy bpf_mem_alloc into temp structure
and wait for rcu barrier-s in the worker to let the rest of
hash map freeing to proceed.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220902211058.60789-17-alexei.starovoitov@gmail.com
For bpf_mem_cache based hash maps the following stress test:
for (i = 1; i <= 512; i <<= 1)
for (j = 1; j <= 1 << 18; j <<= 1)
fd = bpf_map_create(BPF_MAP_TYPE_HASH, NULL, i, j, 2, 0);
creates many kmem_cache-s that are not mergeable in debug kernels
and consume unnecessary amount of memory.
Turned out bpf_mem_cache's free_list logic does batching well,
so usage of kmem_cache for fixes size allocations doesn't bring
any performance benefits vs normal kmalloc.
Hence get rid of kmem_cache in bpf_mem_cache.
That saves memory, speeds up map create/destroy operations,
while maintains hash map update/delete performance.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220902211058.60789-16-alexei.starovoitov@gmail.com
Since hash map is now converted to bpf_mem_alloc and it's waiting for rcu and
rcu_tasks_trace GPs before freeing elements into global memory slabs it's safe
to use dynamically allocated hash maps in sleepable bpf programs.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220902211058.60789-15-alexei.starovoitov@gmail.com
Use call_rcu_tasks_trace() to wait for sleepable progs to finish.
Then use call_rcu() to wait for normal progs to finish
and finally do free_one() on each element when freeing objects
into global memory pool.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220902211058.60789-14-alexei.starovoitov@gmail.com
The hash map is now fully converted to bpf_mem_alloc. Its implementation is not
allocating synchronously and not calling call_rcu() directly. It's now safe to
use non-preallocated hash maps in all types of tracing programs including
BPF_PROG_TYPE_PERF_EVENT that runs out of NMI context.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220902211058.60789-13-alexei.starovoitov@gmail.com
Convert dynamic allocations in percpu hash map from alloc_percpu() to
bpf_mem_cache_alloc() from per-cpu bpf_mem_alloc. Since bpf_mem_alloc frees
objects after RCU gp the call_rcu() is removed. pcpu_init_value() now needs to
zero-fill per-cpu allocations, since dynamically allocated map elements are now
similar to full prealloc, since alloc_percpu() is not called inline and the
elements are reused in the freelist.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220902211058.60789-12-alexei.starovoitov@gmail.com
Extend bpf_mem_alloc to cache free list of fixed size per-cpu allocations.
Once such cache is created bpf_mem_cache_alloc() will return per-cpu objects.
bpf_mem_cache_free() will free them back into global per-cpu pool after
observing RCU grace period.
per-cpu flavor of bpf_mem_alloc is going to be used by per-cpu hash maps.
The free list cache consists of tuples { llist_node, per-cpu pointer }
Unlike alloc_percpu() that returns per-cpu pointer
the bpf_mem_cache_alloc() returns a pointer to per-cpu pointer and
bpf_mem_cache_free() expects to receive it back.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220902211058.60789-11-alexei.starovoitov@gmail.com
SLAB_TYPESAFE_BY_RCU makes kmem_caches non mergeable and slows down
kmem_cache_destroy. All bpf_mem_cache are safe to share across different maps
and programs. Convert SLAB_TYPESAFE_BY_RCU to batched call_rcu. This change
solves the memory consumption issue, avoids kmem_cache_destroy latency and
keeps bpf hash map performance the same.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220902211058.60789-10-alexei.starovoitov@gmail.com
The same low/high watermarks for every bucket in bpf_mem_cache consume
significant amount of memory. Preallocating 64 elements of 4096 bytes each in
the free list is not efficient. Make low/high watermarks and batching value
dependent on element size. This change brings significant memory savings.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220902211058.60789-9-alexei.starovoitov@gmail.com
Doing call_rcu() million times a second becomes a bottle neck.
Convert non-preallocated hash map from call_rcu to SLAB_TYPESAFE_BY_RCU.
The rcu critical section is no longer observed for one htab element
which makes non-preallocated hash map behave just like preallocated hash map.
The map elements are released back to kernel memory after observing
rcu critical section.
This improves 'map_perf_test 4' performance from 100k events per second
to 250k events per second.
bpf_mem_alloc + percpu_counter + typesafe_by_rcu provide 10x performance
boost to non-preallocated hash map and make it within few % of preallocated map
while consuming fraction of memory.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220902211058.60789-8-alexei.starovoitov@gmail.com
The atomic_inc/dec might cause extreme cache line bouncing when multiple cpus
access the same bpf map. Based on specified max_entries for the hash map
calculate when percpu_counter becomes faster than atomic_t and use it for such
maps. For example samples/bpf/map_perf_test is using hash map with max_entries
1000. On a system with 16 cpus the 'map_perf_test 4' shows 14k events per
second using atomic_t. On a system with 15 cpus it shows 100k events per second
using percpu. map_perf_test is an extreme case where all cpus colliding on
atomic_t which causes extreme cache bouncing. Note that the slow path of
percpu_counter is 5k events per secound vs 14k for atomic, so the heuristic is
necessary. See comment in the code why the heuristic is based on
num_online_cpus().
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220902211058.60789-7-alexei.starovoitov@gmail.com
Since bpf hash map was converted to use bpf_mem_alloc it is safe to use
from tracing programs and in RT kernels.
But per-cpu hash map is still using dynamic allocation for per-cpu map
values, hence keep the warning for this map type.
In the future alloc_percpu_gfp can be front-end-ed with bpf_mem_cache
and this restriction will be completely lifted.
perf_event (NMI) bpf programs have to use preallocated hash maps,
because free_htab_elem() is using call_rcu which might crash if re-entered.
Sleepable bpf programs have to use preallocated hash maps, because
life time of the map elements is not protected by rcu_read_lock/unlock.
This restriction can be lifted in the future as well.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220902211058.60789-6-alexei.starovoitov@gmail.com
Tracing BPF programs can attach to kprobe and fentry. Hence they
run in unknown context where calling plain kmalloc() might not be safe.
Front-end kmalloc() with minimal per-cpu cache of free elements.
Refill this cache asynchronously from irq_work.
BPF programs always run with migration disabled.
It's safe to allocate from cache of the current cpu with irqs disabled.
Free-ing is always done into bucket of the current cpu as well.
irq_work trims extra free elements from buckets with kfree
and refills them with kmalloc, so global kmalloc logic takes care
of freeing objects allocated by one cpu and freed on another.
struct bpf_mem_alloc supports two modes:
- When size != 0 create kmem_cache and bpf_mem_cache for each cpu.
This is typical bpf hash map use case when all elements have equal size.
- When size == 0 allocate 11 bpf_mem_cache-s for each cpu, then rely on
kmalloc/kfree. Max allocation size is 4096 in this case.
This is bpf_dynptr and bpf_kptr use case.
bpf_mem_alloc/bpf_mem_free are bpf specific 'wrappers' of kmalloc/kfree.
bpf_mem_cache_alloc/bpf_mem_cache_free are 'wrappers' of kmem_cache_alloc/kmem_cache_free.
The allocators are NMI-safe from bpf programs only. They are not NMI-safe in general.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220902211058.60789-2-alexei.starovoitov@gmail.com
When CONFIG_SECURITY_NETWORK is disabled, there will be build warnings
from resolve_btfids:
WARN: resolve_btfids: unresolved symbol bpf_lsm_socket_socketpair
......
WARN: resolve_btfids: unresolved symbol bpf_lsm_inet_conn_established
Fixing it by wrapping these BTF ID definitions by CONFIG_SECURITY_NETWORK.
Fixes: 69fd337a97 ("bpf: per-cgroup lsm flavor")
Fixes: 9113d7e48e ("bpf: expose bpf_{g,s}etsockopt to lsm cgroup")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20220901065126.3856297-1-houtao@huaweicloud.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
The assignment of the else and else if branches is the same, so the else
if here is redundant, so we remove it and add a comment to make the code
here readable.
./kernel/bpf/cgroup_iter.c:81:6-8: WARNING: possible condition with no effect (if == else).
Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=2016
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220831021618.86770-1-jiapeng.chong@linux.alibaba.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Both __this_cpu_inc_return() and __this_cpu_dec() are not preemption
safe and now migrate_disable() doesn't disable preemption, so the update
of prog-active is not atomic and in theory under fully preemptible kernel
recurisve prevention may do not work.
Fixing by using the preemption-safe and IRQ-safe variants.
Fixes: ca06f55b90 ("bpf: Add per-program recursion prevention mechanism")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20220901061938.3789460-3-houtao@huaweicloud.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Now migrate_disable() does not disable preemption and under some
architectures (e.g. arm64) __this_cpu_{inc|dec|inc_return} are neither
preemption-safe nor IRQ-safe, so for fully preemptible kernel concurrent
lookups or updates on the same task local storage and on the same CPU
may make bpf_task_storage_busy be imbalanced, and
bpf_task_storage_trylock() on the specific cpu will always fail.
Fixing it by using this_cpu_{inc|dec|inc_return} when manipulating
bpf_task_storage_busy.
Fixes: bc235cdb42 ("bpf: Prevent deadlock from recursive bpf_task_storage_[get|delete]")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20220901061938.3789460-2-houtao@huaweicloud.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
In __htab_map_lookup_and_delete_batch() if htab_lock_bucket() returns
-EBUSY, it will go to next bucket. Going to next bucket may not only
skip the elements in current bucket silently, but also incur
out-of-bound memory access or expose kernel memory to userspace if
current bucket_cnt is greater than bucket_size or zero.
Fixing it by stopping batch operation and returning -EBUSY when
htab_lock_bucket() fails, and the application can retry or skip the busy
batch as needed.
Fixes: 20b6cc34ea ("bpf: Avoid hashtab deadlock with map_locked")
Reported-by: Hao Sun <sunhao.th@gmail.com>
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20220831042629.130006-3-houtao@huaweicloud.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Per-cpu htab->map_locked is used to prohibit the concurrent accesses
from both NMI and non-NMI contexts. But since commit 74d862b682
("sched: Make migrate_disable/enable() independent of RT"),
migrate_disable() is also preemptible under CONFIG_PREEMPT case, so now
map_locked also disallows concurrent updates from normal contexts
(e.g. userspace processes) unexpectedly as shown below:
process A process B
htab_map_update_elem()
htab_lock_bucket()
migrate_disable()
/* return 1 */
__this_cpu_inc_return()
/* preempted by B */
htab_map_update_elem()
/* the same bucket as A */
htab_lock_bucket()
migrate_disable()
/* return 2, so lock fails */
__this_cpu_inc_return()
return -EBUSY
A fix that seems feasible is using in_nmi() in htab_lock_bucket() and
only checking the value of map_locked for nmi context. But it will
re-introduce dead-lock on bucket lock if htab_lock_bucket() is re-entered
through non-tracing program (e.g. fentry program).
One cannot use preempt_disable() to fix this issue as htab_use_raw_lock
being false causes the bucket lock to be a spin lock which can sleep and
does not work with preempt_disable().
Therefore, use migrate_disable() when using the spinlock instead of
preempt_disable() and defer fixing concurrent updates to when the kernel
has its own BPF memory allocator.
Fixes: 74d862b682 ("sched: Make migrate_disable/enable() independent of RT")
Reviewed-by: Hao Luo <haoluo@google.com>
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20220831042629.130006-2-houtao@huaweicloud.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Daniel borkmann says:
====================
The following pull-request contains BPF updates for your *net* tree.
We've added 11 non-merge commits during the last 14 day(s) which contain
a total of 13 files changed, 61 insertions(+), 24 deletions(-).
The main changes are:
1) Fix BPF verifier's precision tracking around BPF ring buffer, from Kumar Kartikeya Dwivedi.
2) Fix regression in tunnel key infra when passing FLOWI_FLAG_ANYSRC, from Eyal Birger.
3) Fix insufficient permissions for bpf_sys_bpf() helper, from YiFei Zhu.
4) Fix splat from hitting BUG when purging effective cgroup programs, from Pu Lehui.
5) Fix range tracking for array poke descriptors, from Daniel Borkmann.
6) Fix corrupted packets for XDP_SHARED_UMEM in aligned mode, from Magnus Karlsson.
7) Fix NULL pointer splat in BPF sockmap sk_msg_recvmsg(), from Liu Jian.
8) Add READ_ONCE() to bpf_jit_limit when reading from sysctl, from Kuniyuki Iwashima.
9) Add BPF selftest lru_bug check to s390x deny list, from Daniel Müller.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Add BPF_MAP_GET_FD_BY_ID and BPF_MAP_DELETE_PROG.
Only BPF_MAP_GET_FD_BY_ID needs to be amended to be able
to access the bpf pointer either from the userspace or the kernel.
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20220824134055.1328882-7-benjamin.tissoires@redhat.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
bpf_cgroup_iter_order is globally visible but the entries do not have
CGROUP prefix. As requested by Andrii, put a CGROUP in the names
in bpf_cgroup_iter_order.
This patch fixes two previous commits: one introduced the API and
the other uses the API in bpf selftest (that is, the selftest
cgroup_hierarchical_stats).
I tested this patch via the following command:
test_progs -t cgroup,iter,btf_dump
Fixes: d4ccaf58a8 ("bpf: Introduce cgroup iter")
Fixes: 88886309d2 ("selftests/bpf: add a selftest for cgroup hierarchical stats collection")
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Hao Luo <haoluo@google.com>
Link: https://lore.kernel.org/r/20220825223936.1865810-1-haoluo@google.com
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Hsin-Wei reported a KASAN splat triggered by their BPF runtime fuzzer which
is based on a customized syzkaller:
BUG: KASAN: slab-out-of-bounds in bpf_int_jit_compile+0x1257/0x13f0
Read of size 8 at addr ffff888004e90b58 by task syz-executor.0/1489
CPU: 1 PID: 1489 Comm: syz-executor.0 Not tainted 5.19.0 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.13.0-1ubuntu1.1 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x9c/0xc9
print_address_description.constprop.0+0x1f/0x1f0
? bpf_int_jit_compile+0x1257/0x13f0
kasan_report.cold+0xeb/0x197
? kvmalloc_node+0x170/0x200
? bpf_int_jit_compile+0x1257/0x13f0
bpf_int_jit_compile+0x1257/0x13f0
? arch_prepare_bpf_dispatcher+0xd0/0xd0
? rcu_read_lock_sched_held+0x43/0x70
bpf_prog_select_runtime+0x3e8/0x640
? bpf_obj_name_cpy+0x149/0x1b0
bpf_prog_load+0x102f/0x2220
? __bpf_prog_put.constprop.0+0x220/0x220
? find_held_lock+0x2c/0x110
? __might_fault+0xd6/0x180
? lock_downgrade+0x6e0/0x6e0
? lock_is_held_type+0xa6/0x120
? __might_fault+0x147/0x180
__sys_bpf+0x137b/0x6070
? bpf_perf_link_attach+0x530/0x530
? new_sync_read+0x600/0x600
? __fget_files+0x255/0x450
? lock_downgrade+0x6e0/0x6e0
? fput+0x30/0x1a0
? ksys_write+0x1a8/0x260
__x64_sys_bpf+0x7a/0xc0
? syscall_enter_from_user_mode+0x21/0x70
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f917c4e2c2d
The problem here is that a range of tnum_range(0, map->max_entries - 1) has
limited ability to represent the concrete tight range with the tnum as the
set of resulting states from value + mask can result in a superset of the
actual intended range, and as such a tnum_in(range, reg->var_off) check may
yield true when it shouldn't, for example tnum_range(0, 2) would result in
00XX -> v = 0000, m = 0011 such that the intended set of {0, 1, 2} is here
represented by a less precise superset of {0, 1, 2, 3}. As the register is
known const scalar, really just use the concrete reg->var_off.value for the
upper index check.
Fixes: d2e4c1e6c2 ("bpf: Constant map key tracking for prog array pokes")
Reported-by: Hsin-Wei Hung <hsinweih@uci.edu>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/r/984b37f9fdf7ac36831d2137415a4a915744c1b6.1661462653.git.daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Precision markers need to be propagated whenever we have an ARG_CONST_*
style argument, as the verifier cannot consider imprecise scalars to be
equivalent for the purposes of states_equal check when such arguments
refine the return value (in this case, set mem_size for PTR_TO_MEM). The
resultant mem_size for the R0 is derived from the constant value, and if
the verifier incorrectly prunes states considering them equivalent where
such arguments exist (by seeing that both registers have reg->precise as
false in regsafe), we can end up with invalid programs passing the
verifier which can do access beyond what should have been the correct
mem_size in that explored state.
To show a concrete example of the problem:
0000000000000000 <prog>:
0: r2 = *(u32 *)(r1 + 80)
1: r1 = *(u32 *)(r1 + 76)
2: r3 = r1
3: r3 += 4
4: if r3 > r2 goto +18 <LBB5_5>
5: w2 = 0
6: *(u32 *)(r1 + 0) = r2
7: r1 = *(u32 *)(r1 + 0)
8: r2 = 1
9: if w1 == 0 goto +1 <LBB5_3>
10: r2 = -1
0000000000000058 <LBB5_3>:
11: r1 = 0 ll
13: r3 = 0
14: call bpf_ringbuf_reserve
15: if r0 == 0 goto +7 <LBB5_5>
16: r1 = r0
17: r1 += 16777215
18: w2 = 0
19: *(u8 *)(r1 + 0) = r2
20: r1 = r0
21: r2 = 0
22: call bpf_ringbuf_submit
00000000000000b8 <LBB5_5>:
23: w0 = 0
24: exit
For the first case, the single line execution's exploration will prune
the search at insn 14 for the branch insn 9's second leg as it will be
verified first using r2 = -1 (UINT_MAX), while as w1 at insn 9 will
always be 0 so at runtime we don't get error for being greater than
UINT_MAX/4 from bpf_ringbuf_reserve. The verifier during regsafe just
sees reg->precise as false for both r2 registers in both states, hence
considers them equal for purposes of states_equal.
If we propagated precise markers using the backtracking support, we
would use the precise marking to then ensure that old r2 (UINT_MAX) was
within the new r2 (1) and this would never be true, so the verification
would rightfully fail.
The end result is that the out of bounds access at instruction 19 would
be permitted without this fix.
Note that reg->precise is always set to true when user does not have
CAP_BPF (or when subprog count is greater than 1 (i.e. use of any static
or global functions)), hence this is only a problem when precision marks
need to be explicitly propagated (i.e. privileged users with CAP_BPF).
A simplified test case has been included in the next patch to prevent
future regressions.
Fixes: 457f44363a ("bpf: Implement BPF ring buffer and verifier support for it")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220823185300.406-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cgroup_iter is a type of bpf_iter. It walks over cgroups in four modes:
- walking a cgroup's descendants in pre-order.
- walking a cgroup's descendants in post-order.
- walking a cgroup's ancestors.
- process only the given cgroup.
When attaching cgroup_iter, one can set a cgroup to the iter_link
created from attaching. This cgroup is passed as a file descriptor
or cgroup id and serves as the starting point of the walk. If no
cgroup is specified, the starting point will be the root cgroup v2.
For walking descendants, one can specify the order: either pre-order or
post-order. For walking ancestors, the walk starts at the specified
cgroup and ends at the root.
One can also terminate the walk early by returning 1 from the iter
program.
Note that because walking cgroup hierarchy holds cgroup_mutex, the iter
program is called with cgroup_mutex held.
Currently only one session is supported, which means, depending on the
volume of data bpf program intends to send to user space, the number
of cgroups that can be walked is limited. For example, given the current
buffer size is 8 * PAGE_SIZE, if the program sends 64B data for each
cgroup, assuming PAGE_SIZE is 4kb, the total number of cgroups that can
be walked is 512. This is a limitation of cgroup_iter. If the output
data is larger than the kernel buffer size, after all data in the
kernel buffer is consumed by user space, the subsequent read() syscall
will signal EOPNOTSUPP. In order to work around, the user may have to
update their program to reduce the volume of data sent to output. For
example, skip some uninteresting cgroups. In future, we may extend
bpf_iter flags to allow customizing buffer size.
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Hao Luo <haoluo@google.com>
Link: https://lore.kernel.org/r/20220824233117.1312810-2-haoluo@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently, verifier verifies callback functions (sync and async) as if
they will be executed once, (i.e. it explores execution state as if the
function was being called once). The next insn to explore is set to
start of subprog and the exit from nested frame is handled using
curframe > 0 and prepare_func_exit. In case of async callback it uses a
customized variant of push_stack simulating a kind of branch to set up
custom state and execution context for the async callback.
While this approach is simple and works when callback really will be
executed only once, it is unsafe for all of our current helpers which
are for_each style, i.e. they execute the callback multiple times.
A callback releasing acquired references of the caller may do so
multiple times, but currently verifier sees it as one call inside the
frame, which then returns to caller. Hence, it thinks it released some
reference that the cb e.g. got access through callback_ctx (register
filled inside cb from spilled typed register on stack).
Similarly, it may see that an acquire call is unpaired inside the
callback, so the caller will copy the reference state of callback and
then will have to release the register with new ref_obj_ids. But again,
the callback may execute multiple times, but the verifier will only
account for acquired references for a single symbolic execution of the
callback, which will cause leaks.
Note that for async callback case, things are different. While currently
we have bpf_timer_set_callback which only executes it once, even for
multiple executions it would be safe, as reference state is NULL and
check_reference_leak would force program to release state before
BPF_EXIT. The state is also unaffected by analysis for the caller frame.
Hence async callback is safe.
Since we want the reference state to be accessible, e.g. for pointers
loaded from stack through callback_ctx's PTR_TO_STACK, we still have to
copy caller's reference_state to callback's bpf_func_state, but we
enforce that whatever references it adds to that reference_state has
been released before it hits BPF_EXIT. This requires introducing a new
callback_ref member in the reference state to distinguish between caller
vs callee references. Hence, check_reference_leak now errors out if it
sees we are in callback_fn and we have not released callback_ref refs.
Since there can be multiple nested callbacks, like frame 0 -> cb1 -> cb2
etc. we need to also distinguish between whether this particular ref
belongs to this callback frame or parent, and only error for our own, so
we store state->frameno (which is always non-zero for callbacks).
In short, callbacks can read parent reference_state, but cannot mutate
it, to be able to use pointers acquired by the caller. They must only
undo their changes (by releasing their own acquired_refs before
BPF_EXIT) on top of caller reference_state before returning (at which
point the caller and callback state will match anyway, so no need to
copy it back to caller).
Fixes: 69c087ba62 ("bpf: Add bpf_for_each_map_elem() helper")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220823013125.24938-1-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
They would require func_info which needs prog BTF anyway. Loading BTF
and setting the prog btf_fd while loading the prog indirectly requires
CAP_BPF, so just to reduce confusion, move both these helpers taking
callback under bpf_capable() protection as well, since they cannot be
used without CAP_BPF.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220823013117.24916-1-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
bpf_strncmp is already exposed everywhere. The motivation is to keep
those helpers in kernel/bpf/helpers.c. Otherwise it's tempting to move
them under kernel/bpf/cgroup.c because they are currently only used
by sysctl prog types.
Suggested-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20220823222555.523590-4-sdf@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The following hooks are per-cgroup hooks but they are not
using cgroup_{common,current}_func_proto, fix it:
* BPF_PROG_TYPE_CGROUP_SKB (cg_skb)
* BPF_PROG_TYPE_CGROUP_SOCK_ADDR (cg_sock_addr)
* BPF_PROG_TYPE_CGROUP_SOCK (cg_sock)
* BPF_PROG_TYPE_LSM+BPF_LSM_CGROUP
Also:
* move common func_proto's into cgroup func_proto handlers
* make sure bpf_{g,s}et_retval are not accessible from recvmsg,
getpeername and getsockname (return/errno is ignored in these
places)
* as a side effect, expose get_current_pid_tgid, get_current_comm_proto,
get_current_ancestor_cgroup_id, get_cgroup_classid to more cgroup
hooks
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20220823222555.523590-3-sdf@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Split cgroup_base_func_proto into the following:
* cgroup_common_func_proto - common helpers for all cgroup hooks
* cgroup_current_func_proto - common helpers for all cgroup hooks
running in the process context (== have meaningful 'current').
Move bpf_{g,s}et_retval and other cgroup-related helpers into
kernel/bpf/cgroup.c so they closer to where they are being used.
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/r/20220823222555.523590-2-sdf@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
While reading bpf_jit_limit, it can be changed concurrently via sysctl,
WRITE_ONCE() in __do_proc_doulongvec_minmax(). The size of bpf_jit_limit
is long, so we need to add a paired READ_ONCE() to avoid load-tearing.
Fixes: ede95a63b5 ("bpf: add bpf_jit_limit knob to restrict unpriv allocations")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220823215804.2177-1-kuniyu@amazon.com
The bpf-iter-prog for tcp and unix sk can do bpf_setsockopt()
which needs has_current_bpf_ctx() to decide if it is called by a
bpf prog. This patch initializes the bpf_run_ctx in
bpf_iter_run_prog() for the has_current_bpf_ctx() to use.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/r/20220817061751.4177657-1-kafai@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Andrii Nakryiko says:
====================
bpf-next 2022-08-17
We've added 45 non-merge commits during the last 14 day(s) which contain
a total of 61 files changed, 986 insertions(+), 372 deletions(-).
The main changes are:
1) New bpf_ktime_get_tai_ns() BPF helper to access CLOCK_TAI, from Kurt
Kanzenbach and Jesper Dangaard Brouer.
2) Few clean ups and improvements for libbpf 1.0, from Andrii Nakryiko.
3) Expose crash_kexec() as kfunc for BPF programs, from Artem Savkov.
4) Add ability to define sleepable-only kfuncs, from Benjamin Tissoires.
5) Teach libbpf's bpf_prog_load() and bpf_map_create() to gracefully handle
unsupported names on old kernels, from Hangbin Liu.
6) Allow opting out from auto-attaching BPF programs by libbpf's BPF skeleton,
from Hao Luo.
7) Relax libbpf's requirement for shared libs to be marked executable, from
Henqgi Chen.
8) Improve bpf_iter internals handling of error returns, from Hao Luo.
9) Few accommodations in libbpf to support GCC-BPF quirks, from James Hilliard.
10) Fix BPF verifier logic around tracking dynptr ref_obj_id, from Joanne Koong.
11) bpftool improvements to handle full BPF program names better, from Manu
Bretelle.
12) bpftool fixes around libcap use, from Quentin Monnet.
13) BPF map internals clean ups and improvements around memory allocations,
from Yafang Shao.
14) Allow to use cgroup_get_from_file() on cgroupv1, allowing BPF cgroup
iterator to work on cgroupv1, from Yosry Ahmed.
15) BPF verifier internal clean ups, from Dave Marchevsky and Joanne Koong.
16) Various fixes and clean ups for selftests/bpf and vmtest.sh, from Daniel
Xu, Artem Savkov, Joanne Koong, Andrii Nakryiko, Shibin Koikkara Reeny.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (45 commits)
selftests/bpf: Few fixes for selftests/bpf built in release mode
libbpf: Clean up deprecated and legacy aliases
libbpf: Streamline bpf_attr and perf_event_attr initialization
libbpf: Fix potential NULL dereference when parsing ELF
selftests/bpf: Tests libbpf autoattach APIs
libbpf: Allows disabling auto attach
selftests/bpf: Fix attach point for non-x86 arches in test_progs/lsm
libbpf: Making bpf_prog_load() ignore name if kernel doesn't support
selftests/bpf: Update CI kconfig
selftests/bpf: Add connmark read test
selftests/bpf: Add existing connection bpf_*_ct_lookup() test
bpftool: Clear errno after libcap's checks
bpf: Clear up confusion in bpf_skb_adjust_room()'s documentation
bpftool: Fix a typo in a comment
libbpf: Add names for auxiliary maps
bpf: Use bpf_map_area_alloc consistently on bpf map creation
bpf: Make __GFP_NOWARN consistent in bpf map creation
bpf: Use bpf_map_area_free instread of kvfree
bpf: Remove unneeded memset in queue_stack_map creation
libbpf: preserve errno across pr_warn/pr_info/pr_debug
...
====================
Link: https://lore.kernel.org/r/20220817215656.1180215-1-andrii@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
bpf_sk_reuseport_detach() calls __rcu_dereference_sk_user_data_with_flags()
to obtain the value of sk->sk_user_data, but that function is only usable
if the RCU read lock is held, and neither that function nor any of its
callers hold it.
Fix this by adding a new helper, __locked_read_sk_user_data_with_flags()
that checks to see if sk->sk_callback_lock() is held and use that here
instead.
Alternatively, making __rcu_dereference_sk_user_data_with_flags() use
rcu_dereference_checked() might suffice.
Without this, the following warning can be occasionally observed:
=============================
WARNING: suspicious RCU usage
6.0.0-rc1-build2+ #563 Not tainted
-----------------------------
include/net/sock.h:592 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
5 locks held by locktest/29873:
#0: ffff88812734b550 (&sb->s_type->i_mutex_key#9){+.+.}-{3:3}, at: __sock_release+0x77/0x121
#1: ffff88812f5621b0 (sk_lock-AF_INET){+.+.}-{0:0}, at: tcp_close+0x1c/0x70
#2: ffff88810312f5c8 (&h->lhash2[i].lock){+.+.}-{2:2}, at: inet_unhash+0x76/0x1c0
#3: ffffffff83768bb8 (reuseport_lock){+...}-{2:2}, at: reuseport_detach_sock+0x18/0xdd
#4: ffff88812f562438 (clock-AF_INET){++..}-{2:2}, at: bpf_sk_reuseport_detach+0x24/0xa4
stack backtrace:
CPU: 1 PID: 29873 Comm: locktest Not tainted 6.0.0-rc1-build2+ #563
Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014
Call Trace:
<TASK>
dump_stack_lvl+0x4c/0x5f
bpf_sk_reuseport_detach+0x6d/0xa4
reuseport_detach_sock+0x75/0xdd
inet_unhash+0xa5/0x1c0
tcp_set_state+0x169/0x20f
? lockdep_sock_is_held+0x3a/0x3a
? __lock_release.isra.0+0x13e/0x220
? reacquire_held_locks+0x1bb/0x1bb
? hlock_class+0x31/0x96
? mark_lock+0x9e/0x1af
__tcp_close+0x50/0x4b6
tcp_close+0x28/0x70
inet_release+0x8e/0xa7
__sock_release+0x95/0x121
sock_close+0x14/0x17
__fput+0x20f/0x36a
task_work_run+0xa3/0xcc
exit_to_user_mode_prepare+0x9c/0x14d
syscall_exit_to_user_mode+0x18/0x44
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Fixes: cf8c1e9672 ("net: refactor bpf_sk_reuseport_detach()")
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Hawkins Jiawei <yin31149@gmail.com>
Link: https://lore.kernel.org/r/166064248071.3502205.10036394558814861778.stgit@warthog.procyon.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The verifier cannot perform sufficient validation of any pointers passed
into bpf_attr and treats them as integers rather than pointers. The helper
will then read from arbitrary pointers passed into it. Restrict the helper
to CAP_PERFMON since the security model in BPF of arbitrary kernel read is
CAP_BPF + CAP_PERFMON.
Fixes: af2ac3e13e ("bpf: Prepare bpf syscall to be used from kernel and user space.")
Signed-off-by: YiFei Zhu <zhuyifei@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220816205517.682470-1-zhuyifei@google.com
Users may want to audit calls to security_create_user_ns() and access
user space memory. Also create_user_ns() runs without
pagefault_disabled(). Therefore, make bpf_lsm_userns_create() sleepable
for mandatory access control policies.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Acked-by: KP Singh <kpsingh@kernel.org>
Signed-off-by: Frederick Lawler <fred@cloudflare.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Shut up this warning:
kernel/bpf/syscall.c:5089:5: warning: no previous prototype for function 'kern_sys_bpf' [-Wmissing-prototypes]
int kern_sys_bpf(int cmd, union bpf_attr *attr, unsigned int size)
Reported-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Daniel Borkmann says:
====================
bpf 2022-08-10
We've added 23 non-merge commits during the last 7 day(s) which contain
a total of 19 files changed, 424 insertions(+), 35 deletions(-).
The main changes are:
1) Several fixes for BPF map iterator such as UAFs along with selftests, from Hou Tao.
2) Fix BPF syscall program's {copy,strncpy}_from_bpfptr() to not fault, from Jinghao Jia.
3) Reject BPF syscall programs calling BPF_PROG_RUN, from Alexei Starovoitov and YiFei Zhu.
4) Fix attach_btf_obj_id info to pick proper target BTF, from Stanislav Fomichev.
5) BPF design Q/A doc update to clarify what is not stable ABI, from Paul E. McKenney.
6) Fix BPF map's prealloc_lru_pop to not reinitialize, from Kumar Kartikeya Dwivedi.
7) Fix bpf_trampoline_put to avoid leaking ftrace hash, from Jiri Olsa.
8) Fix arm64 JIT to address sparse errors around BPF trampoline, from Xu Kuohai.
9) Fix arm64 JIT to use kvcalloc instead of kcalloc for internal program address
offset buffer, from Aijun Sun.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf: (23 commits)
selftests/bpf: Ensure sleepable program is rejected by hash map iter
selftests/bpf: Add write tests for sk local storage map iterator
selftests/bpf: Add tests for reading a dangling map iter fd
bpf: Only allow sleepable program for resched-able iterator
bpf: Check the validity of max_rdwr_access for sock local storage map iterator
bpf: Acquire map uref in .init_seq_private for sock{map,hash} iterator
bpf: Acquire map uref in .init_seq_private for sock local storage map iterator
bpf: Acquire map uref in .init_seq_private for hash map iterator
bpf: Acquire map uref in .init_seq_private for array map iterator
bpf: Disallow bpf programs call prog_run command.
bpf, arm64: Fix bpf trampoline instruction endianness
selftests/bpf: Add test for prealloc_lru_pop bug
bpf: Don't reinit map value in prealloc_lru_pop
bpf: Allow calling bpf_prog_test kfuncs in tracing programs
bpf, arm64: Allocate program buffer using kvcalloc instead of kcalloc
selftests/bpf: Excercise bpf_obj_get_info_by_fd for bpf2bpf
bpf: Use proper target btf when exporting attach_btf_obj_id
mptcp, btf: Add struct mptcp_sock definition when CONFIG_MPTCP is disabled
bpf: Cleanup ftrace hash in bpf_trampoline_put
BPF: Fix potential bad pointer dereference in bpf_sys_bpf()
...
====================
Link: https://lore.kernel.org/r/20220810190624.10748-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Refactor sk_user_data dereference using more generic function
__rcu_dereference_sk_user_data_with_flags(), which improve its
maintainability
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Some of the bpf maps are created with __GFP_NOWARN, i.e. arraymap,
bloom_filter, bpf_local_storage, bpf_struct_ops, lpm_trie,
queue_stack_maps, reuseport_array, stackmap and xskmap, while others are
created without __GFP_NOWARN, i.e. cpumap, devmap, hashtab,
local_storage, offload, ringbuf and sock_map. But there are not key
differences between the creation of these maps. So let make this
allocation flag consistent in all bpf maps creation. Then we can use a
generic helper to alloc all bpf maps.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20220810151840.16394-4-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When a sleepable program is attached to a hash map iterator, might_fault()
will report "BUG: sleeping function called from invalid context..." if
CONFIG_DEBUG_ATOMIC_SLEEP is enabled. The reason is that rcu_read_lock()
is held in bpf_hash_map_seq_next() and won't be released until all elements
are traversed or bpf_hash_map_seq_stop() is called.
Fixing it by reusing BPF_ITER_RESCHED to indicate that only non-sleepable
program is allowed for iterator without BPF_ITER_RESCHED. We can revise
bpf_iter_link_attach() later if there are other conditions which may
cause rcu_read_lock() or spin_lock() issues.
Signed-off-by: Hou Tao <houtao1@huawei.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220810080538.1845898-7-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
bpf_iter_attach_map() acquires a map uref, and the uref may be released
before or in the middle of iterating map elements. For example, the uref
could be released in bpf_iter_detach_map() as part of
bpf_link_release(), or could be released in bpf_map_put_with_uref() as
part of bpf_map_release().
So acquiring an extra map uref in bpf_iter_init_hash_map() and
releasing it in bpf_iter_fini_hash_map().
Fixes: d6c4503cc2 ("bpf: Implement bpf iterator for hash maps")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220810080538.1845898-3-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
bpf_iter_attach_map() acquires a map uref, and the uref may be released
before or in the middle of iterating map elements. For example, the uref
could be released in bpf_iter_detach_map() as part of
bpf_link_release(), or could be released in bpf_map_put_with_uref() as
part of bpf_map_release().
Alternative fix is acquiring an extra bpf_link reference just like
a pinned map iterator does, but it introduces unnecessary dependency
on bpf_link instead of bpf_map.
So choose another fix: acquiring an extra map uref in .init_seq_private
for array map iterator.
Fixes: d3cc2ab546 ("bpf: Implement bpf iterator for array maps")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220810080538.1845898-2-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The verifier cannot perform sufficient validation of bpf_attr->test.ctx_in
pointer, therefore bpf programs should not be allowed to call BPF_PROG_RUN
command from within the program.
To fix this issue split bpf_sys_bpf() bpf helper into normal kern_sys_bpf()
kernel function that can only be used by the kernel light skeleton directly.
Reported-by: YiFei Zhu <zhuyifei@google.com>
Fixes: b1d18a7574 ("bpf: Extend sys_bpf commands for bpf_syscall programs.")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add KF_DESTRUCTIVE flag for destructive functions. Functions with this
flag set will require CAP_SYS_BOOT capabilities.
Signed-off-by: Artem Savkov <asavkov@redhat.com>
Link: https://lore.kernel.org/r/20220810065905.475418-2-asavkov@redhat.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The LRU map that is preallocated may have its elements reused while
another program holds a pointer to it from bpf_map_lookup_elem. Hence,
only check_and_free_fields is appropriate when the element is being
deleted, as it ensures proper synchronization against concurrent access
of the map value. After that, we cannot call check_and_init_map_value
again as it may rewrite bpf_spin_lock, bpf_timer, and kptr fields while
they can be concurrently accessed from a BPF program.
This is safe to do as when the map entry is deleted, concurrent access
is protected against by check_and_free_fields, i.e. an existing timer
would be freed, and any existing kptr will be released by it. The
program can create further timers and kptrs after check_and_free_fields,
but they will eventually be released once the preallocated items are
freed on map destruction, even if the item is never reused again. Hence,
the deleted item sitting in the free list can still have resources
attached to it, and they would never leak.
With spin_lock, we never touch the field at all on delete or update, as
we may end up modifying the state of the lock. Since the verifier
ensures that a bpf_spin_lock call is always paired with bpf_spin_unlock
call, the program will eventually release the lock so that on reuse the
new user of the value can take the lock.
Essentially, for the preallocated case, we must assume that the map
value may always be in use by the program, even when it is sitting in
the freelist, and handle things accordingly, i.e. use proper
synchronization inside check_and_free_fields, and never reinitialize the
special fields when it is reused on update.
Fixes: 68134668c1 ("bpf: Add map side support for bpf timers.")
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/r/20220809213033.24147-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When a data slice is obtained from a dynptr (through the bpf_dynptr_data API),
the ref obj id of the dynptr must be found and then associated with the data
slice.
The ref obj id of the dynptr must be found *before* the caller saved regs are
reset. Without this fix, the ref obj id tracking is not correct for
dynptrs that are at an offset from the frame pointer.
Please also note that the data slice's ref obj id must be assigned after the
ret types are parsed, since RET_PTR_TO_ALLOC_MEM-type return regs get
zero-marked.
Fixes: 34d4ef5775 ("bpf: Add dynptr data slices")
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20220809214055.4050604-1-joannelkoong@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently in funciton __get_type_size(), the corresponding
btf_type is returned only in invalid cases. Let us always
return btf_type regardless of valid or invalid cases.
Such a new functionality will be used in subsequent patches.
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220807175116.4179242-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Commit 3dc6ffae2d ("timekeeping: Introduce fast accessor to clock tai")
introduced a fast and NMI-safe accessor for CLOCK_TAI. Especially in time
sensitive networks (TSN), where all nodes are synchronized by Precision Time
Protocol (PTP), it's helpful to have the possibility to generate timestamps
based on CLOCK_TAI instead of CLOCK_MONOTONIC. With a BPF helper for TAI in
place, it becomes very convenient to correlate activity across different
machines in the network.
Use cases for such a BPF helper include functionalities such as Tx launch
time (e.g. ETF and TAPRIO Qdiscs) and timestamping.
Note: CLOCK_TAI is nothing new per se, only the NMI-safe variant of it is.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
[Kurt: Wrote changelog and renamed helper]
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Link: https://lore.kernel.org/r/20220809060803.5773-2-kurt@linutronix.de
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Discussion around a recently-submitted patch provided historical
context for check_refcount_ok [0]. Specifically, the function and its
helpers - may_be_acquire_function and arg_type_may_be_refcounted -
predate the OBJ_RELEASE type flag and the addition of many more helpers
with acquire/release semantics.
The purpose of check_refcount_ok is to ensure:
1) Helper doesn't have multiple uses of return reg's ref_obj_id
2) Helper with release semantics only has one arg needing to be
released, since that's tracked using meta->ref_obj_id
With current verifier, it's safe to remove check_refcount_ok and its
helpers. Since addition of OBJ_RELEASE type flag, case 2) has been
handled by the arg_type_is_release check in check_func_arg. To ensure
case 1) won't result in verifier silently prioritizing one use of
ref_obj_id, this patch adds a helper_multiple_ref_obj_use check which
fails loudly if a helper passes > 1 test for use of ref_obj_id.
[0]: lore.kernel.org/bpf/20220713234529.4154673-1-davemarchevsky@fb.com
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Joanne Koong <joannelkoong@gmail.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220808171559.3251090-1-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In bpf_seq_read, seq->op->next() could return an ERR and jump to
the label stop. However, the existing code in stop does not handle
the case when p (returned from next()) is an ERR. Adds the handling
of ERR of p by converting p into an error and jumping to done.
Because all the current implementations do not have a case that
returns ERR from next(), so this patch doesn't have behavior changes
right now.
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Hao Luo <haoluo@google.com>
Link: https://lore.kernel.org/r/20220805214821.1058337-4-haoluo@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This allows to declare a kfunc as sleepable and prevents its use in
a non sleepable program.
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Co-developed-by: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Hao Luo <haoluo@google.com>
Link: https://lore.kernel.org/r/20220805214821.1058337-2-haoluo@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch cleans up a few things in the verifier:
* type_is_pkt_pointer():
Future work (skb + xdp dynptrs [0]) will be using the reg type
PTR_TO_PACKET | PTR_MAYBE_NULL. type_is_pkt_pointer() should return
true for any type whose base type is PTR_TO_PACKET, regardless of
flags attached to it.
* reg_type_may_be_refcounted_or_null():
Get the base type at the start of the function to avoid
having to recompute it / improve readability
* check_func_proto(): remove unnecessary 'meta' arg
* check_helper_call():
Use switch casing on the base type of return value instead of
nested ifs on the full type
There are no functional behavior changes.
[0] https://lore.kernel.org/bpf/20220726184706.954822-1-joannelkoong@gmail.com/
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20220802214638.3643235-1-joannelkoong@gmail.com
When attaching to program, the program itself might not be attached
to anything (and, hence, might not have attach_btf), so we can't
unconditionally use 'prog->aux->dst_prog->aux->attach_btf'.
Instead, use bpf_prog_get_target_btf to pick proper target BTF:
* when attached to dst_prog, use dst_prog->aux->btf
* when attached to kernel btf, use prog->aux->attach_btf
Fixes: b79c9fc955 ("bpf: implement BPF_PROG_QUERY for BPF_LSM_CGROUP")
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Hao Luo <haoluo@google.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220804201140.1340684-1-sdf@google.com
We need to release possible hash from trampoline fops object
before removing it, otherwise we leak it.
Fixes: 00963a2e75 ("bpf: Support bpf_trampoline on functions with IPMODIFY (e.g. livepatch)")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/bpf/20220802135651.1794015-1-jolsa@kernel.org
Core
----
- Refactor the forward memory allocation to better cope with memory
pressure with many open sockets, moving from a per socket cache to
a per-CPU one
- Replace rwlocks with RCU for better fairness in ping, raw sockets
and IP multicast router.
- Network-side support for IO uring zero-copy send.
- A few skb drop reason improvements, including codegen the source file
with string mapping instead of using macro magic.
- Rename reference tracking helpers to a more consistent
netdev_* schema.
- Adapt u64_stats_t type to address load/store tearing issues.
- Refine debug helper usage to reduce the log noise caused by bots.
BPF
---
- Improve socket map performance, avoiding skb cloning on read
operation.
- Add support for 64 bits enum, to match types exposed by kernel.
- Introduce support for sleepable uprobes program.
- Introduce support for enum textual representation in libbpf.
- New helpers to implement synproxy with eBPF/XDP.
- Improve loop performances, inlining indirect calls when
possible.
- Removed all the deprecated libbpf APIs.
- Implement new eBPF-based LSM flavor.
- Add type match support, which allow accurate queries to the
eBPF used types.
- A few TCP congetsion control framework usability improvements.
- Add new infrastructure to manipulate CT entries via eBPF programs.
- Allow for livepatch (KLP) and BPF trampolines to attach to the same
kernel function.
Protocols
---------
- Introduce per network namespace lookup tables for unix sockets,
increasing scalability and reducing contention.
- Preparation work for Wi-Fi 7 Multi-Link Operation (MLO) support.
- Add support to forciby close TIME_WAIT TCP sockets via user-space
tools.
- Significant performance improvement for the TLS 1.3 receive path,
both for zero-copy and not-zero-copy.
- Support for changing the initial MTPCP subflow priority/backup
status
- Introduce virtually contingus buffers for sockets over RDMA,
to cope better with memory pressure.
- Extend CAN ethtool support with timestamping capabilities
- Refactor CAN build infrastructure to allow building only the needed
features.
Driver API
----------
- Remove devlink mutex to allow parallel commands on multiple links.
- Add support for pause stats in distributed switch.
- Implement devlink helpers to query and flash line cards.
- New helper for phy mode to register conversion.
New hardware / drivers
----------------------
- Ethernet DSA driver for the rockchip mt7531 on BPI-R2 Pro.
- Ethernet DSA driver for the Renesas RZ/N1 A5PSW switch.
- Ethernet DSA driver for the Microchip LAN937x switch.
- Ethernet PHY driver for the Aquantia AQR113C EPHY.
- CAN driver for the OBD-II ELM327 interface.
- CAN driver for RZ/N1 SJA1000 CAN controller.
- Bluetooth: Infineon CYW55572 Wi-Fi plus Bluetooth combo device.
Drivers
-------
- Intel Ethernet NICs:
- i40e: add support for vlan pruning
- i40e: add support for XDP framented packets
- ice: improved vlan offload support
- ice: add support for PPPoE offload
- Mellanox Ethernet (mlx5)
- refactor packet steering offload for performance and scalability
- extend support for TC offload
- refactor devlink code to clean-up the locking schema
- support stacked vlans for bridge offloads
- use TLS objects pool to improve connection rate
- Netronome Ethernet NICs (nfp):
- extend support for IPv6 fields mangling offload
- add support for vepa mode in HW bridge
- better support for virtio data path acceleration (VDPA)
- enable TSO by default
- Microsoft vNIC driver (mana)
- add support for XDP redirect
- Others Ethernet drivers:
- bonding: add per-port priority support
- microchip lan743x: extend phy support
- Fungible funeth: support UDP segmentation offload and XDP xmit
- Solarflare EF100: add support for virtual function representors
- MediaTek SoC: add XDP support
- Mellanox Ethernet/IB switch (mlxsw):
- dropped support for unreleased H/W (XM router).
- improved stats accuracy
- unified bridge model coversion improving scalability
(parts 1-6)
- support for PTP in Spectrum-2 asics
- Broadcom PHYs
- add PTP support for BCM54210E
- add support for the BCM53128 internal PHY
- Marvell Ethernet switches (prestera):
- implement support for multicast forwarding offload
- Embedded Ethernet switches:
- refactor OcteonTx MAC filter for better scalability
- improve TC H/W offload for the Felix driver
- refactor the Microchip ksz8 and ksz9477 drivers to share
the probe code (parts 1, 2), add support for phylink
mac configuration
- Other WiFi:
- Microchip wilc1000: diable WEP support and enable WPA3
- Atheros ath10k: encapsulation offload support
Old code removal:
- Neterion vxge ethernet driver: this is untouched since more than
10 years.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Merge tag 'net-next-6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
Pull networking changes from Paolo Abeni:
"Core:
- Refactor the forward memory allocation to better cope with memory
pressure with many open sockets, moving from a per socket cache to
a per-CPU one
- Replace rwlocks with RCU for better fairness in ping, raw sockets
and IP multicast router.
- Network-side support for IO uring zero-copy send.
- A few skb drop reason improvements, including codegen the source
file with string mapping instead of using macro magic.
- Rename reference tracking helpers to a more consistent netdev_*
schema.
- Adapt u64_stats_t type to address load/store tearing issues.
- Refine debug helper usage to reduce the log noise caused by bots.
BPF:
- Improve socket map performance, avoiding skb cloning on read
operation.
- Add support for 64 bits enum, to match types exposed by kernel.
- Introduce support for sleepable uprobes program.
- Introduce support for enum textual representation in libbpf.
- New helpers to implement synproxy with eBPF/XDP.
- Improve loop performances, inlining indirect calls when possible.
- Removed all the deprecated libbpf APIs.
- Implement new eBPF-based LSM flavor.
- Add type match support, which allow accurate queries to the eBPF
used types.
- A few TCP congetsion control framework usability improvements.
- Add new infrastructure to manipulate CT entries via eBPF programs.
- Allow for livepatch (KLP) and BPF trampolines to attach to the same
kernel function.
Protocols:
- Introduce per network namespace lookup tables for unix sockets,
increasing scalability and reducing contention.
- Preparation work for Wi-Fi 7 Multi-Link Operation (MLO) support.
- Add support to forciby close TIME_WAIT TCP sockets via user-space
tools.
- Significant performance improvement for the TLS 1.3 receive path,
both for zero-copy and not-zero-copy.
- Support for changing the initial MTPCP subflow priority/backup
status
- Introduce virtually contingus buffers for sockets over RDMA, to
cope better with memory pressure.
- Extend CAN ethtool support with timestamping capabilities
- Refactor CAN build infrastructure to allow building only the needed
features.
Driver API:
- Remove devlink mutex to allow parallel commands on multiple links.
- Add support for pause stats in distributed switch.
- Implement devlink helpers to query and flash line cards.
- New helper for phy mode to register conversion.
New hardware / drivers:
- Ethernet DSA driver for the rockchip mt7531 on BPI-R2 Pro.
- Ethernet DSA driver for the Renesas RZ/N1 A5PSW switch.
- Ethernet DSA driver for the Microchip LAN937x switch.
- Ethernet PHY driver for the Aquantia AQR113C EPHY.
- CAN driver for the OBD-II ELM327 interface.
- CAN driver for RZ/N1 SJA1000 CAN controller.
- Bluetooth: Infineon CYW55572 Wi-Fi plus Bluetooth combo device.
Drivers:
- Intel Ethernet NICs:
- i40e: add support for vlan pruning
- i40e: add support for XDP framented packets
- ice: improved vlan offload support
- ice: add support for PPPoE offload
- Mellanox Ethernet (mlx5)
- refactor packet steering offload for performance and scalability
- extend support for TC offload
- refactor devlink code to clean-up the locking schema
- support stacked vlans for bridge offloads
- use TLS objects pool to improve connection rate
- Netronome Ethernet NICs (nfp):
- extend support for IPv6 fields mangling offload
- add support for vepa mode in HW bridge
- better support for virtio data path acceleration (VDPA)
- enable TSO by default
- Microsoft vNIC driver (mana)
- add support for XDP redirect
- Others Ethernet drivers:
- bonding: add per-port priority support
- microchip lan743x: extend phy support
- Fungible funeth: support UDP segmentation offload and XDP xmit
- Solarflare EF100: add support for virtual function representors
- MediaTek SoC: add XDP support
- Mellanox Ethernet/IB switch (mlxsw):
- dropped support for unreleased H/W (XM router).
- improved stats accuracy
- unified bridge model coversion improving scalability (parts 1-6)
- support for PTP in Spectrum-2 asics
- Broadcom PHYs
- add PTP support for BCM54210E
- add support for the BCM53128 internal PHY
- Marvell Ethernet switches (prestera):
- implement support for multicast forwarding offload
- Embedded Ethernet switches:
- refactor OcteonTx MAC filter for better scalability
- improve TC H/W offload for the Felix driver
- refactor the Microchip ksz8 and ksz9477 drivers to share the
probe code (parts 1, 2), add support for phylink mac
configuration
- Other WiFi:
- Microchip wilc1000: diable WEP support and enable WPA3
- Atheros ath10k: encapsulation offload support
Old code removal:
- Neterion vxge ethernet driver: this is untouched since more than 10 years"
* tag 'net-next-6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1890 commits)
doc: sfp-phylink: Fix a broken reference
wireguard: selftests: support UML
wireguard: allowedips: don't corrupt stack when detecting overflow
wireguard: selftests: update config fragments
wireguard: ratelimiter: use hrtimer in selftest
net/mlx5e: xsk: Discard unaligned XSK frames on striding RQ
net: usb: ax88179_178a: Bind only to vendor-specific interface
selftests: net: fix IOAM test skip return code
net: usb: make USB_RTL8153_ECM non user configurable
net: marvell: prestera: remove reduntant code
octeontx2-pf: Reduce minimum mtu size to 60
net: devlink: Fix missing mutex_unlock() call
net/tls: Remove redundant workqueue flush before destroy
net: txgbe: Fix an error handling path in txgbe_probe()
net: dsa: Fix spelling mistakes and cleanup code
Documentation: devlink: add add devlink-selftests to the table of contents
dccp: put dccp_qpolicy_full() and dccp_qpolicy_push() in the same lock
net: ionic: fix error check for vlan flags in ionic_set_nic_features()
net: ice: fix error NETIF_F_HW_VLAN_CTAG_FILTER check in ice_vsi_sync_fltr()
nfp: flower: add support for tunnel offload without key ID
...
magical no_llseek thing and makes checks consistent. In particular,
ad-hoc "can we do splice via internal pipe" checks got saner (and
somewhat more permissive, which is what Jason had been after, AFAICT)
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'pull-work.lseek' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs lseek updates from Al Viro:
"Jason's lseek series.
Saner handling of 'lseek should fail with ESPIPE' - this gets rid of
the magical no_llseek thing and makes checks consistent.
In particular, the ad-hoc "can we do splice via internal pipe" checks
got saner (and somewhat more permissive, which is what Jason had been
after, AFAICT)"
* tag 'pull-work.lseek' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fs: remove no_llseek
fs: check FMODE_LSEEK to control internal pipe splicing
vfio: do not set FMODE_LSEEK flag
dma-buf: remove useless FMODE_LSEEK flag
fs: do not compare against ->llseek
fs: clear or set FMODE_LSEEK based on llseek function
When multiple threads are attaching/detaching fentry/fexit programs to
the same trampoline, we may call register_fentry on the same trampoline
twice: register_fentry(), unregister_fentry(), then register_fentry again.
This causes ftrace_set_filter_ip() for the same ip on tr->fops twice,
which leaves duplicated ip in tr->fops. The extra ip is not cleaned up
properly on unregister and thus causes failures with further register in
register_ftrace_direct_multi():
register_ftrace_direct_multi()
{
...
for (i = 0; i < size; i++) {
hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
if (ftrace_find_rec_direct(entry->ip))
goto out_unlock;
}
}
...
}
This can be triggered with parallel fentry/fexit tests with test_progs:
./test_progs -t fentry,fexit -j
Fix this by resetting tr->fops in ftrace_set_filter_ip(), so that there
will never be duplicated entries in tr->fops.
Fixes: 00963a2e75 ("bpf: Support bpf_trampoline on functions with IPMODIFY (e.g. livepatch)")
Reported-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220729194106.1207472-1-song@kernel.org
vsnprintf returns the number of characters which would have been written if
enough space had been available, excluding the terminating null byte. Thus,
the return value of 'len_left' means that the last character has been
dropped.
Signed-off-by: Fedor Tokarev <ftokarev@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/bpf/20220711211317.GA1143610@laptop
Daniel Borkmann says:
====================
bpf-next 2022-07-22
We've added 73 non-merge commits during the last 12 day(s) which contain
a total of 88 files changed, 3458 insertions(+), 860 deletions(-).
The main changes are:
1) Implement BPF trampoline for arm64 JIT, from Xu Kuohai.
2) Add ksyscall/kretsyscall section support to libbpf to simplify tracing kernel
syscalls through kprobe mechanism, from Andrii Nakryiko.
3) Allow for livepatch (KLP) and BPF trampolines to attach to the same kernel
function, from Song Liu & Jiri Olsa.
4) Add new kfunc infrastructure for netfilter's CT e.g. to insert and change
entries, from Kumar Kartikeya Dwivedi & Lorenzo Bianconi.
5) Add a ksym BPF iterator to allow for more flexible and efficient interactions
with kernel symbols, from Alan Maguire.
6) Bug fixes in libbpf e.g. for uprobe binary path resolution, from Dan Carpenter.
7) Fix BPF subprog function names in stack traces, from Alexei Starovoitov.
8) libbpf support for writing custom perf event readers, from Jon Doron.
9) Switch to use SPDX tag for BPF helper man page, from Alejandro Colomar.
10) Fix xsk send-only sockets when in busy poll mode, from Maciej Fijalkowski.
11) Reparent BPF maps and their charging on memcg offlining, from Roman Gushchin.
12) Multiple follow-up fixes around BPF lsm cgroup infra, from Stanislav Fomichev.
13) Use bootstrap version of bpftool where possible to speed up builds, from Pu Lehui.
14) Cleanup BPF verifier's check_func_arg() handling, from Joanne Koong.
15) Make non-prealloced BPF map allocations low priority to play better with
memcg limits, from Yafang Shao.
16) Fix BPF test runner to reject zero-length data for skbs, from Zhengchao Shao.
17) Various smaller cleanups and improvements all over the place.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (73 commits)
bpf: Simplify bpf_prog_pack_[size|mask]
bpf: Support bpf_trampoline on functions with IPMODIFY (e.g. livepatch)
bpf, x64: Allow to use caller address from stack
ftrace: Allow IPMODIFY and DIRECT ops on the same function
ftrace: Add modify_ftrace_direct_multi_nolock
bpf/selftests: Fix couldn't retrieve pinned program in xdp veth test
bpf: Fix build error in case of !CONFIG_DEBUG_INFO_BTF
selftests/bpf: Fix test_verifier failed test in unprivileged mode
selftests/bpf: Add negative tests for new nf_conntrack kfuncs
selftests/bpf: Add tests for new nf_conntrack kfuncs
selftests/bpf: Add verifier tests for trusted kfunc args
net: netfilter: Add kfuncs to set and change CT status
net: netfilter: Add kfuncs to set and change CT timeout
net: netfilter: Add kfuncs to allocate and insert CT
net: netfilter: Deduplicate code in bpf_{xdp,skb}_ct_lookup
bpf: Add documentation for kfuncs
bpf: Add support for forcing kfunc args to be trusted
bpf: Switch to new kfunc flags infrastructure
tools/resolve_btfids: Add support for 8-byte BTF sets
bpf: Introduce 8-byte BTF set
...
====================
Link: https://lore.kernel.org/r/20220722221218.29943-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Simplify the logic that selects bpf_prog_pack_size, and always use
(PMD_SIZE * num_possible_nodes()). This is a good tradeoff, as most of
the performance benefit observed is from less direct map fragmentation [0].
Also, module_alloc(4MB) may not allocate 4MB aligned memory. Therefore,
we cannot use (ptr & bpf_prog_pack_mask) to find the correct address of
bpf_prog_pack. Fix this by checking the header address falls in the range
of pack->ptr and (pack->ptr + bpf_prog_pack_size).
[0] https://lore.kernel.org/bpf/20220707223546.4124919-1-song@kernel.org/
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20220713204950.3015201-1-song@kernel.org
When tracing a function with IPMODIFY ftrace_ops (livepatch), the bpf
trampoline must follow the instruction pointer saved on stack. This needs
extra handling for bpf trampolines with BPF_TRAMP_F_CALL_ORIG flag.
Implement bpf_tramp_ftrace_ops_func and use it for the ftrace_ops used
by BPF trampoline. This enables tracing functions with livepatch.
This also requires moving bpf trampoline to *_ftrace_direct_mult APIs.
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/all/20220602193706.2607681-2-song@kernel.org/
Link: https://lore.kernel.org/bpf/20220720002126.803253-5-song@kernel.org
Teach the verifier to detect a new KF_TRUSTED_ARGS kfunc flag, which
means each pointer argument must be trusted, which we define as a
pointer that is referenced (has non-zero ref_obj_id) and also needs to
have its offset unchanged, similar to how release functions expect their
argument. This allows a kfunc to receive pointer arguments unchanged
from the result of the acquire kfunc.
This is required to ensure that kfunc that operate on some object only
work on acquired pointers and not normal PTR_TO_BTF_ID with same type
which can be obtained by pointer walking. The restrictions applied to
release arguments also apply to trusted arguments. This implies that
strict type matching (not deducing type by recursively following members
at offset) and OBJ_RELEASE offset checks (ensuring they are zero) are
used for trusted pointer arguments.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220721134245.2450-5-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Instead of populating multiple sets to indicate some attribute and then
researching the same BTF ID in them, prepare a single unified BTF set
which indicates whether a kfunc is allowed to be called, and also its
attributes if any at the same time. Now, only one call is needed to
perform the lookup for both kfunc availability and its attributes.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220721134245.2450-4-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Syzkaller found a problem similar to d1a6edecc1 ("bpf: Check
attach_func_proto more carefully in check_return_code") where
attach_func_proto might be NULL:
RIP: 0010:check_helper_call+0x3dcb/0x8d50 kernel/bpf/verifier.c:7330
do_check kernel/bpf/verifier.c:12302 [inline]
do_check_common+0x6e1e/0xb980 kernel/bpf/verifier.c:14610
do_check_main kernel/bpf/verifier.c:14673 [inline]
bpf_check+0x661e/0xc520 kernel/bpf/verifier.c:15243
bpf_prog_load+0x11ae/0x1f80 kernel/bpf/syscall.c:2620
With the following reproducer:
bpf$BPF_PROG_RAW_TRACEPOINT_LOAD(0x5, &(0x7f0000000780)={0xf, 0x4, &(0x7f0000000040)=@framed={{}, [@call={0x85, 0x0, 0x0, 0xbb}]}, &(0x7f0000000000)='GPL\x00', 0x0, 0x0, 0x0, 0x0, 0x0, '\x00', 0x0, 0x2b, 0xffffffffffffffff, 0x8, 0x0, 0x0, 0x10, 0x0}, 0x80)
Let's do the same here, only check attach_func_proto for the prog types
where we are certain that attach_func_proto is defined.
Fixes: 69fd337a97 ("bpf: per-cgroup lsm flavor")
Reported-by: syzbot+0f8d989b1fba1addc5e0@syzkaller.appspotmail.com
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220720164729.147544-1-sdf@google.com
Syscall-side map_lookup_elem() and map_update_elem() used to use
kmalloc() to allocate temporary buffers of value_size, so
KMALLOC_MAX_SIZE limit on value_size made sense to prevent creation of
array map that won't be accessible through syscall interface.
But this limitation since has been lifted by relying on kvmalloc() in
syscall handling code. So remove KMALLOC_MAX_SIZE, which among other
things means that it's possible to have BPF global variable sections
(.bss, .data, .rodata) bigger than 8MB now. Keep the sanity check to
prevent trivial overflows like round_up(map->value_size, 8) and restrict
value size to <= INT_MAX (2GB).
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220715053146.1291891-4-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
BPF_MAP_TYPE_ARRAY is rounding value_size to closest multiple of 8 and
stores that as array->elem_size for various memory allocations and
accesses.
But the code tends to re-calculate round_up(map->value_size, 8) in
multiple places instead of using array->elem_size. Cleaning this up and
making sure we always use array->size to avoid duplication of this
(admittedly simple) logic for consistency.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220715053146.1291891-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
