As part of on ongoing effort to perform more automated testing and
provide more tools for individual developers to validate their
patches before submitting, we are trying to make our code
"clang-format clean". My hope is that once we have fixed all of our
style "quirks", developers will be able to run clang-format on their
patches to help avoid silly formatting problems and ensure their
changes fit in well with the rest of the SELinux kernel code.
Signed-off-by: Paul Moore <paul@paul-moore.com>
As part of on ongoing effort to perform more automated testing and
provide more tools for individual developers to validate their
patches before submitting, we are trying to make our code
"clang-format clean". My hope is that once we have fixed all of our
style "quirks", developers will be able to run clang-format on their
patches to help avoid silly formatting problems and ensure their
changes fit in well with the rest of the SELinux kernel code.
Signed-off-by: Paul Moore <paul@paul-moore.com>
As part of on ongoing effort to perform more automated testing and
provide more tools for individual developers to validate their
patches before submitting, we are trying to make our code
"clang-format clean". My hope is that once we have fixed all of our
style "quirks", developers will be able to run clang-format on their
patches to help avoid silly formatting problems and ensure their
changes fit in well with the rest of the SELinux kernel code.
Signed-off-by: Paul Moore <paul@paul-moore.com>
As part of on ongoing effort to perform more automated testing and
provide more tools for individual developers to validate their
patches before submitting, we are trying to make our code
"clang-format clean". My hope is that once we have fixed all of our
style "quirks", developers will be able to run clang-format on their
patches to help avoid silly formatting problems and ensure their
changes fit in well with the rest of the SELinux kernel code.
Signed-off-by: Paul Moore <paul@paul-moore.com>
As part of on ongoing effort to perform more automated testing and
provide more tools for individual developers to validate their
patches before submitting, we are trying to make our code
"clang-format clean". My hope is that once we have fixed all of our
style "quirks", developers will be able to run clang-format on their
patches to help avoid silly formatting problems and ensure their
changes fit in well with the rest of the SELinux kernel code.
Signed-off-by: Paul Moore <paul@paul-moore.com>
As part of on ongoing effort to perform more automated testing and
provide more tools for individual developers to validate their
patches before submitting, we are trying to make our code
"clang-format clean". My hope is that once we have fixed all of our
style "quirks", developers will be able to run clang-format on their
patches to help avoid silly formatting problems and ensure their
changes fit in well with the rest of the SELinux kernel code.
Signed-off-by: Paul Moore <paul@paul-moore.com>
As part of on ongoing effort to perform more automated testing and
provide more tools for individual developers to validate their
patches before submitting, we are trying to make our code
"clang-format clean". My hope is that once we have fixed all of our
style "quirks", developers will be able to run clang-format on their
patches to help avoid silly formatting problems and ensure their
changes fit in well with the rest of the SELinux kernel code.
Signed-off-by: Paul Moore <paul@paul-moore.com>
As part of on ongoing effort to perform more automated testing and
provide more tools for individual developers to validate their
patches before submitting, we are trying to make our code
"clang-format clean". My hope is that once we have fixed all of our
style "quirks", developers will be able to run clang-format on their
patches to help avoid silly formatting problems and ensure their
changes fit in well with the rest of the SELinux kernel code.
Signed-off-by: Paul Moore <paul@paul-moore.com>
As part of on ongoing effort to perform more automated testing and
provide more tools for individual developers to validate their
patches before submitting, we are trying to make our code
"clang-format clean". My hope is that once we have fixed all of our
style "quirks", developers will be able to run clang-format on their
patches to help avoid silly formatting problems and ensure their
changes fit in well with the rest of the SELinux kernel code.
Signed-off-by: Paul Moore <paul@paul-moore.com>
Currently, SELinux doesn't allow distinguishing between kernel threads
and userspace processes that are started before the policy is first
loaded - both get the label corresponding to the kernel SID. The only
way a process that persists from early boot can get a meaningful label
is by doing a voluntary dyntransition or re-executing itself.
Reusing the kernel label for userspace processes is problematic for
several reasons:
1. The kernel is considered to be a privileged domain and generally
needs to have a wide range of permissions allowed to work correctly,
which prevents the policy writer from effectively hardening against
early boot processes that might remain running unintentionally after
the policy is loaded (they represent a potential extra attack surface
that should be mitigated).
2. Despite the kernel being treated as a privileged domain, the policy
writer may want to impose certain special limitations on kernel
threads that may conflict with the requirements of intentional early
boot processes. For example, it is a good hardening practice to limit
what executables the kernel can execute as usermode helpers and to
confine the resulting usermode helper processes. However, a
(legitimate) process surviving from early boot may need to execute a
different set of executables.
3. As currently implemented, overlayfs remembers the security context of
the process that created an overlayfs mount and uses it to bound
subsequent operations on files using this context. If an overlayfs
mount is created before the SELinux policy is loaded, these "mounter"
checks are made against the kernel context, which may clash with
restrictions on the kernel domain (see 2.).
To resolve this, introduce a new initial SID (reusing the slot of the
former "init" initial SID) that will be assigned to any userspace
process started before the policy is first loaded. This is easy to do,
as we can simply label any process that goes through the
bprm_creds_for_exec LSM hook with the new init-SID instead of
propagating the kernel SID from the parent.
To provide backwards compatibility for existing policies that are
unaware of this new semantic of the "init" initial SID, introduce a new
policy capability "userspace_initial_context" and set the "init" SID to
the same context as the "kernel" SID unless this capability is set by
the policy.
Another small backwards compatibility measure is needed in
security_sid_to_context_core() for before the initial SELinux policy
load - see the code comment for explanation.
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Stephen Smalley <stephen.smalley.work@gmail.com>
[PM: edited comments based on feedback/discussion]
Signed-off-by: Paul Moore <paul@paul-moore.com>
In four separate functions within avtab, the same comparison logic is
used. The only difference is how the result is handled or whether there
is a unique specifier value to be checked for or used.
Extracting this functionality into the avtab_node_cmp() function unifies
the comparison logic between searching and insertion and gets rid of
duplicative code so that the implementation is easier to maintain.
Signed-off-by: Jacob Satterfield <jsatterfield.linux@gmail.com>
Reviewed-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Using full_name_hash() instead of partial_name_hash() should result
in cleaner and better performing code.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>
__hashtab_insert() in hashtab.h has a cleaner interface that allows the
caller to specify the chain node location that the new node is being
inserted into so that it can update the node that currently occupies it.
Signed-off-by: Jacob Satterfield <jsatterfield.linux@gmail.com>
Reviewed-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
avtab_read_item() is a hot function called when reading each rule in a
binary policydb. With the current Fedora policy and refpolicy, this
function is called nearly 100,000 times per policy load.
A single avtab node is only permitted to have a single specifier to
describe the data it holds. As such, a check is performed to make sure
only one specifier is set. Previously this was done via a for-loop.
However, there is already an optimal function for finding the number of
bits set (hamming weight) and on some architectures, dedicated
instructions (popcount) which can be executed much more efficiently.
Even when using -mcpu=generic on a x86-64 Fedora 38 VM, this commit
results in a modest 2-4% speedup for policy loading due to a substantial
reduction in the number of instructions executed.
Signed-off-by: Jacob Satterfield <jsatterfield.linux@gmail.com>
Reviewed-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The number of buckets is calculated by performing a binary AND against
the mask of the hash table, which is one less than its size (which is a
power of two). This leads to all top bits being discarded, e.g. with
the Reference Policy on Debian there exists 376 entries, leading to a
size of 512, discarding the top 23 bits.
Use jhash to improve the hash table utilization:
# current
roletr: 376 entries and 124/512 buckets used,
longest chain length 8, sum of chain length^2 1496
# patch
roletr: 376 entries and 266/512 buckets used,
longest chain length 4, sum of chain length^2 646
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Reviewed-by: Stephen Smalley <stephen.smalley.work@gmail.com>
[PM: line wrap in the commit description]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Instead of dividing by 8 and then performing log2 by hand, use a more
readable calculation.
The behavior of rounddown_pow_of_two() for an input of 0 is undefined,
so handle that case and small values manually to achieve the same
results.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Reviewed-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Print the sum of chain lengths squared as a metric for hash tables to
provide more insights, similar to avtabs.
While on it add a comma in the avtab message to improve readability of
the output.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Reviewed-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).
As found with Coccinelle[1], add __counted_by for struct sidtab_str_cache.
[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
Cc: Paul Moore <paul@paul-moore.com>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Ondrej Mosnacek <omosnace@redhat.com>
Cc: selinux@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Merge tag 'selinux-pr-20230829' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux
Pull selinux updates from Paul Moore:
"Thirty three SELinux patches, which is a pretty big number for us, but
there isn't really anything scary in here; in fact we actually manage
to remove 10 lines of code with this :)
- Promote the SELinux DEBUG_HASHES macro to CONFIG_SECURITY_SELINUX_DEBUG
The DEBUG_HASHES macro was a buried SELinux specific preprocessor
debug macro that was a problem waiting to happen. Promoting the
debug macro to a proper Kconfig setting should help both improve
the visibility of the feature as well enable improved test
coverage. We've moved some additional debug functions under the
CONFIG_SECURITY_SELINUX_DEBUG flag and we may see more work in the
future.
- Emit a pr_notice() message if virtual memory is executable by default
As this impacts the SELinux access control policy enforcement, if
the system's configuration is such that virtual memory is
executable by default we print a single line notice to the console.
- Drop avtab_search() in favor of avtab_search_node()
Both functions are nearly identical so we removed avtab_search()
and converted the callers to avtab_search_node().
- Add some SELinux network auditing helpers
The helpers not only reduce a small amount of code duplication, but
they provide an opportunity to improve UDP flood performance
slightly by delaying initialization of the audit data in some
cases.
- Convert GFP_ATOMIC allocators to GFP_KERNEL when reading SELinux policy
There were two SELinux policy load helper functions that were
allocating memory using GFP_ATOMIC, they have been converted to
GFP_KERNEL.
- Quiet a KMSAN warning in selinux_inet_conn_request()
A one-line error path (re)set patch that resolves a KMSAN warning.
It is important to note that this doesn't represent a real bug in
the current code, but it quiets KMSAN and arguably hardens the code
against future changes.
- Cleanup the policy capability accessor functions
This is a follow-up to the patch which reverted SELinux to using a
global selinux_state pointer. This patch cleans up some artifacts
of that change and turns each accessor into a one-line READ_ONCE()
call into the policy capabilities array.
- A number of patches from Christian Göttsche
Christian submitted almost two-thirds of the patches in this pull
request as he worked to harden the SELinux code against type
differences, variable overflows, etc.
- Support for separating early userspace from the kernel in policy,
with a later revert
We did have a patch that added a new userspace initial SID which
would allow SELinux to distinguish between early user processes
created before the initial policy load and the kernel itself.
Unfortunately additional post-merge testing revealed a problematic
interaction with an old SELinux userspace on an old version of
Ubuntu so we've reverted the patch until we can resolve the
compatibility issue.
- Remove some outdated comments dealing with LSM hook registration
When we removed the runtime disable functionality we forgot to
remove some old comments discussing the importance of LSM hook
registration ordering.
- Minor administrative changes
Stephen Smalley updated his email address and "debranded" SELinux
from "NSA SELinux" to simply "SELinux". We've come a long way from
the original NSA submission and I would consider SELinux a true
community project at this point so removing the NSA branding just
makes sense"
* tag 'selinux-pr-20230829' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux: (33 commits)
selinux: prevent KMSAN warning in selinux_inet_conn_request()
selinux: use unsigned iterator in nlmsgtab code
selinux: avoid implicit conversions in policydb code
selinux: avoid implicit conversions in selinuxfs code
selinux: make left shifts well defined
selinux: update type for number of class permissions in services code
selinux: avoid implicit conversions in avtab code
selinux: revert SECINITSID_INIT support
selinux: use GFP_KERNEL while reading binary policy
selinux: update comment on selinux_hooks[]
selinux: avoid implicit conversions in services code
selinux: avoid implicit conversions in mls code
selinux: use identical iterator type in hashtab_duplicate()
selinux: move debug functions into debug configuration
selinux: log about VM being executable by default
selinux: fix a 0/NULL mistmatch in ad_net_init_from_iif()
selinux: introduce SECURITY_SELINUX_DEBUG configuration
selinux: introduce and use lsm_ad_net_init*() helpers
selinux: update my email address
selinux: add missing newlines in pr_err() statements
...
Set the next pointer in filename_trans_read_helper() before attaching
the new node under construction to the list, otherwise garbage would be
dereferenced on subsequent failure during cleanup in the out goto label.
Cc: <stable@vger.kernel.org>
Fixes: 4300590243 ("selinux: implement new format of filename transitions")
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Use the identical type for local variables, e.g. loop counters.
Declare members of struct policydb_compat_info unsigned to consistently
use unsigned iterators. They hold read-only non-negative numbers in the
global variable policydb_compat.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The loops upper bound represent the number of permissions used (for the
current class or in general). The limit for this is 32, thus we might
left shift of one less, 31. Shifting a base of 1 results in undefined
behavior; use (u32)1 as base.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Security classes have only up to 32 permissions, hence using an u16 is
sufficient (while improving padding in struct selinux_mapping).
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Return u32 from avtab_hash() instead of int, since the hashing is done
on u32 and the result is used as an index on the hash array.
Use the type of the limit in for loops.
Avoid signed to unsigned conversion of multiplication result in
avtab_hash_eval() and perform multiplication in destination type.
Use unsigned loop iterator for index operations, to avoid sign
extension.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This commit reverts 5b0eea835d ("selinux: introduce an initial SID
for early boot processes") as it was found to cause problems on
distros with old SELinux userspace tools/libraries, specifically
Ubuntu 16.04.
Hopefully we will be able to re-add this functionality at a later
date, but let's revert this for now to help ensure a stable and
backwards compatible SELinux tree.
Link: https://lore.kernel.org/selinux/87edkseqf8.fsf@mail.lhotse
Acked-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Use GFP_KERNEL instead of GFP_ATOMIC while reading a binary policy in
sens_read() and cat_read(), similar to surrounding code.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Use u32 as the output parameter type in security_get_classes() and
security_get_permissions(), based on the type of the symtab nprim
member.
Declare the read-only class string parameter of
security_get_permissions() const.
Avoid several implicit conversions by using the identical type for the
destination.
Use the type identical to the source for local variables.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: cleanup extra whitespace in subject]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Use u32 for ebitmap bits and sensitivity levels, char for the default
range of a class.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: description tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Use the identical type u32 for the loop iterator.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: remove extra whitespace in subject]
Signed-off-by: Paul Moore <paul@paul-moore.com>
avtab_hash_eval() and hashtab_stat() are only used in policydb.c when
the configuration SECURITY_SELINUX_DEBUG is enabled.
Move the function definitions under that configuration as well and
provide empty definitions in case SECURITY_SELINUX_DEBUG is disabled, to
avoid using #ifdef in the callers.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The policy database code contains several debug output statements
related to hashtable utilization. Those are guarded by the macro
DEBUG_HASHES, which is neither documented nor set anywhere.
Introduce a new Kconfig configuration guarding this and potential
other future debugging related code. Disable the setting by default.
Suggested-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: fixed line lengths in the help text]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Update my email address; MAINTAINERS was updated some time ago.
Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The kernel print statements do not append an implicit newline to format
strings.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: subject line tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
avtab_search() shares the same logic with avtab_search_node(), except
that it returns, if found, a pointer to the struct avtab_node member
datum instead of the node itself. Since the member is an embedded
struct, and not a pointer, the returned value of avtab_search() and
avtab_search_node() will always in unison either be NULL or non-NULL.
Drop avtab_search() and replace its calls by avtab_search_node() to
deduplicate logic and adopt the only caller caring for the type of
the returned value accordingly.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
hashtab_init() takes an u32 as size parameter type.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: subject line tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
The specifier for avtab keys is always supplied with a type of u16,
either as a macro to security_compute_sid() or the member specified of
the struct avtab_key.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Prevent inserting more than the supported U32_MAX number of entries.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The function is always inlined and most of the time both relevant
arguments are compile time constants, allowing compilers to elide the
check. Also the function is part of outputting the policy, which is not
performance critical.
Also convert the type of the third parameter into a size_t, since it
should always be a non-negative number of elements.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Currently, SELinux doesn't allow distinguishing between kernel threads
and userspace processes that are started before the policy is first
loaded - both get the label corresponding to the kernel SID. The only
way a process that persists from early boot can get a meaningful label
is by doing a voluntary dyntransition or re-executing itself.
Reusing the kernel label for userspace processes is problematic for
several reasons:
1. The kernel is considered to be a privileged domain and generally
needs to have a wide range of permissions allowed to work correctly,
which prevents the policy writer from effectively hardening against
early boot processes that might remain running unintentionally after
the policy is loaded (they represent a potential extra attack surface
that should be mitigated).
2. Despite the kernel being treated as a privileged domain, the policy
writer may want to impose certain special limitations on kernel
threads that may conflict with the requirements of intentional early
boot processes. For example, it is a good hardening practice to limit
what executables the kernel can execute as usermode helpers and to
confine the resulting usermode helper processes. However, a
(legitimate) process surviving from early boot may need to execute a
different set of executables.
3. As currently implemented, overlayfs remembers the security context of
the process that created an overlayfs mount and uses it to bound
subsequent operations on files using this context. If an overlayfs
mount is created before the SELinux policy is loaded, these "mounter"
checks are made against the kernel context, which may clash with
restrictions on the kernel domain (see 2.).
To resolve this, introduce a new initial SID (reusing the slot of the
former "init" initial SID) that will be assigned to any userspace
process started before the policy is first loaded. This is easy to do,
as we can simply label any process that goes through the
bprm_creds_for_exec LSM hook with the new init-SID instead of
propagating the kernel SID from the parent.
To provide backwards compatibility for existing policies that are
unaware of this new semantic of the "init" initial SID, introduce a new
policy capability "userspace_initial_context" and set the "init" SID to
the same context as the "kernel" SID unless this capability is set by
the policy.
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Avoid using the identifier `bool` to improve support with future C
standards. C23 is about to make `bool` a predefined macro (see N2654).
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The object context type `fs`, not to be confused with the well used
object context type `fscon`, was introduced in the initial git commit
1da177e4c3 ("Linux-2.6.12-rc2") but never actually used since.
The paper "A Security Policy Configuration for the Security-Enhanced
Linux" [1] mentions it under `7.2 File System Contexts` but also states:
Currently, this configuration is unused.
The policy statement defining such object contexts is `fscon`, e.g.:
fscon 2 3 gen_context(system_u:object_r:conA_t,s0) \
gen_context(system_u:object_r:conB_t,s0)
It is not documented at selinuxproject.org or in the SELinux notebook
and not supported by the Reference Policy buildsystem - the statement is
not properly sorted - and thus not used in the Reference or Fedora
Policy.
Print a warning message at policy load for each such object context:
SELinux: void and deprecated fs ocon 02:03
This topic was initially highlighted by Nicolas Iooss [2].
[1]: https://media.defense.gov/2021/Jul/29/2002815735/-1/-1/0/SELINUX-SECURITY-POLICY-CONFIGURATION-REPORT.PDF
[2]: https://lore.kernel.org/selinux/CAJfZ7=mP2eJaq2BfO3y0VnwUJaY2cS2p=HZMN71z1pKjzaT0Eg@mail.gmail.com/
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: tweaked deprecation comment, description line wrapping]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Commit 53f3517ae0 ("selinux: do not leave dangling pointer behind")
reset the `str` field of the `context` struct in an OOM error branch.
In this struct the fields `str` and `len` are coupled and should be kept
in sync. Set the length to zero according to the string be set to NULL.
Fixes: 53f3517ae0 ("selinux: do not leave dangling pointer behind")
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
A few small tweaks to selinux_audit_rule_init():
- Adjust how we use the @rc variable so we are not doing any extra
work in the common/success case.
- Related to the above, rework the 'out' jump label so that the
success and error paths are different, simplifying both.
- Cleanup some of the vertical whitespace while we are making the
other changes.
Signed-off-by: Paul Moore <paul@paul-moore.com>
The array of mount tokens in only used in match_opt_prefix() and never
modified.
The array of symtab names is never modified and only used in the
DEBUG_HASHES configuration as output.
The array of files for the SElinux filesystem sub-directory `ss` is
similar to the other `struct tree_descr` usages only read from to
construct the containing entries.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The second parameter `tag` of avtab_hash_eval() is only used for
printing. In policydb_index() it is called with a string literal:
avtab_hash_eval(&p->te_avtab, "rules");
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: slight formatting tweak in description]
Signed-off-by: Paul Moore <paul@paul-moore.com>
In case mls_context_cpy() fails due to OOM set the free'd pointer in
context_cpy() to NULL to avoid it potentially being dereferenced or
free'd again in future. Freeing a NULL pointer is well-defined and a
hard NULL dereference crash is at least not exploitable and should give
a workable stack trace.
Fixes: 12b29f3455 ("selinux: support deferred mapping of contexts")
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Linus observed that the pervasive passing of selinux_state pointers
introduced by me in commit aa8e712cee ("selinux: wrap global selinux
state") adds overhead and complexity without providing any
benefit. The original idea was to pave the way for SELinux namespaces
but those have not yet been implemented and there isn't currently
a concrete plan to do so. Remove the passing of the selinux_state
pointers, reverting to direct use of the single global selinux_state,
and likewise remove passing of child pointers like the selinux_avc.
The selinux_policy pointer remains as it is needed for atomic switching
of policies.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202303101057.mZ3Gv5fK-lkp@intel.com/
Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Merge tag 'selinux-pr-20221212' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux
Pull selinux updates from Paul Moore:
"Two SELinux patches: one increases the sleep time on deprecated
functionality, and one removes the indirect calls in the sidtab
context conversion code"
* tag 'selinux-pr-20221212' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
selinux: remove the sidtab context conversion indirect calls
selinux: increase the deprecation sleep for checkreqprot and runtime disable
The sidtab conversion code has support for multiple context
conversion routines through the use of function pointers and
indirect calls. However, the reality is that all current users rely
on the same conversion routine: convert_context(). This patch does
away with this extra complexity and replaces the indirect calls
with direct function calls; allowing us to remove a layer of
obfuscation and create cleaner, more maintainable code.
Reviewed-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The following warning was triggered on a hardware environment:
SELinux: Converting 162 SID table entries...
BUG: sleeping function called from invalid context at
__might_sleep+0x60/0x74 0x0
in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 5943, name: tar
CPU: 7 PID: 5943 Comm: tar Tainted: P O 5.10.0 #1
Call trace:
dump_backtrace+0x0/0x1c8
show_stack+0x18/0x28
dump_stack+0xe8/0x15c
___might_sleep+0x168/0x17c
__might_sleep+0x60/0x74
__kmalloc_track_caller+0xa0/0x7dc
kstrdup+0x54/0xac
convert_context+0x48/0x2e4
sidtab_context_to_sid+0x1c4/0x36c
security_context_to_sid_core+0x168/0x238
security_context_to_sid_default+0x14/0x24
inode_doinit_use_xattr+0x164/0x1e4
inode_doinit_with_dentry+0x1c0/0x488
selinux_d_instantiate+0x20/0x34
security_d_instantiate+0x70/0xbc
d_splice_alias+0x4c/0x3c0
ext4_lookup+0x1d8/0x200 [ext4]
__lookup_slow+0x12c/0x1e4
walk_component+0x100/0x200
path_lookupat+0x88/0x118
filename_lookup+0x98/0x130
user_path_at_empty+0x48/0x60
vfs_statx+0x84/0x140
vfs_fstatat+0x20/0x30
__se_sys_newfstatat+0x30/0x74
__arm64_sys_newfstatat+0x1c/0x2c
el0_svc_common.constprop.0+0x100/0x184
do_el0_svc+0x1c/0x2c
el0_svc+0x20/0x34
el0_sync_handler+0x80/0x17c
el0_sync+0x13c/0x140
SELinux: Context system_u:object_r:pssp_rsyslog_log_t:s0:c0 is
not valid (left unmapped).
It was found that within a critical section of spin_lock_irqsave in
sidtab_context_to_sid(), convert_context() (hooked by
sidtab_convert_params.func) might cause the process to sleep via
allocating memory with GFP_KERNEL, which is problematic.
As Ondrej pointed out [1], convert_context()/sidtab_convert_params.func
has another caller sidtab_convert_tree(), which is okay with GFP_KERNEL.
Therefore, fix this problem by adding a gfp_t argument for
convert_context()/sidtab_convert_params.func and pass GFP_KERNEL/_ATOMIC
properly in individual callers.
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20221018120111.1474581-1-gongruiqi1@huawei.com/ [1]
Reported-by: Tan Ninghao <tanninghao1@huawei.com>
Fixes: ee1a84fdfe ("selinux: overhaul sidtab to fix bug and improve performance")
Signed-off-by: GONG, Ruiqi <gongruiqi1@huawei.com>
Reviewed-by: Ondrej Mosnacek <omosnace@redhat.com>
[PM: wrap long BUG() output lines, tweak subject line]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Declare ebitmap, mls_level and mls_context parameters const where they
are only read from. This allows callers to supply pointers to const
as arguments and increases readability.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Just like next_entry(), boundary check is necessary to prevent memory
out-of-bound access.
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
In this function, it directly returns the result of __security_read_policy
without freeing the allocated memory in *data, cause memory leak issue,
so free the memory if __security_read_policy failed.
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
[PM: subject line tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Merge tag 'selinux-pr-20220523' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux
Pull selinux updates from Paul Moore:
"We've got twelve patches queued for v5.19, with most being fairly
minor. The highlights are below:
- The checkreqprot and runtime disable knobs have been deprecated for
some time with no active users that we can find. In an effort to
move things along we are adding a pause when the knobs are used to
help make the deprecation more noticeable in case anyone is still
using these hacks in the shadows.
- We've added the anonymous inode class name to the AVC audit records
when anonymous inodes are involved. This should make writing policy
easier when anonymous inodes are involved.
- More constification work. This is fairly straightforward and the
source of most of the diffstat.
- The usual minor cleanups: remove unnecessary assignments, assorted
style/checkpatch fixes, kdoc fixes, macro while-loop
encapsulations, #include tweaks, etc"
* tag 'selinux-pr-20220523' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
security: declare member holding string literal const
selinux: log anon inode class name
selinux: declare data arrays const
selinux: fix indentation level of mls_ops block
selinux: include necessary headers in headers
selinux: avoid extra semicolon
selinux: update parameter documentation
selinux: resolve checkpatch errors
selinux: don't sleep when CONFIG_SECURITY_SELINUX_CHECKREQPROT_VALUE is true
selinux: checkreqprot is deprecated, add some ssleep() discomfort
selinux: runtime disable is deprecated, add some ssleep() discomfort
selinux: Remove redundant assignments
The code attempts to free the 'new' pointer using kmem_cache_free(),
which is wrong because this function isn't responsible of freeing it.
Instead, the function should free new->htable and clear the contents of
*new (to prevent double-free).
Cc: stable@vger.kernel.org
Fixes: c7c556f1e8 ("selinux: refactor changing booleans")
Reported-by: Wander Lairson Costa <wander@redhat.com>
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The arrays for the policy capability names, the initial sid identifiers
and the class and permission names are not changed at runtime. Declare
them const to avoid accidental modification.
Do not override the classmap and the initial sid list in the build time
script genheaders.
Check flose(3) is successful in genheaders.c, otherwise the written data
might be corrupted or incomplete.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: manual merge due to fuzz, minor style tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Add one level of indentation to the code block of the label mls_ops in
constraint_expr_eval(), to adjust the trailing break; to the parent
case: branch.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Wrap macro into `do { } while (0)` to avoid Clang emitting warnings
about extra semicolons.
Similar to userspace commit
9d85aa60d1
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: whitespace/indenting tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Reported by checkpatch:
security/selinux/nlmsgtab.c
---------------------------
ERROR: that open brace { should be on the previous line
#29: FILE: security/selinux/nlmsgtab.c:29:
+static const struct nlmsg_perm nlmsg_route_perms[] =
+{
ERROR: that open brace { should be on the previous line
#97: FILE: security/selinux/nlmsgtab.c:97:
+static const struct nlmsg_perm nlmsg_tcpdiag_perms[] =
+{
ERROR: that open brace { should be on the previous line
#105: FILE: security/selinux/nlmsgtab.c:105:
+static const struct nlmsg_perm nlmsg_xfrm_perms[] =
+{
ERROR: that open brace { should be on the previous line
#134: FILE: security/selinux/nlmsgtab.c:134:
+static const struct nlmsg_perm nlmsg_audit_perms[] =
+{
security/selinux/ss/policydb.c
------------------------------
ERROR: that open brace { should be on the previous line
#318: FILE: security/selinux/ss/policydb.c:318:
+static int (*destroy_f[SYM_NUM]) (void *key, void *datum, void *datap) =
+{
ERROR: that open brace { should be on the previous line
#674: FILE: security/selinux/ss/policydb.c:674:
+static int (*index_f[SYM_NUM]) (void *key, void *datum, void *datap) =
+{
ERROR: that open brace { should be on the previous line
#1643: FILE: security/selinux/ss/policydb.c:1643:
+static int (*read_f[SYM_NUM]) (struct policydb *p, struct symtab *s, void *fp) =
+{
ERROR: that open brace { should be on the previous line
#3246: FILE: security/selinux/ss/policydb.c:3246:
+ void *datap) =
+{
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Get rid of redundant assignments which end up in values not being
read either because they are overwritten or the function ends.
Reported by clang-tidy [deadcode.DeadStores]
Signed-off-by: Michal Orzel <michalorzel.eng@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Merge tag 'selinux-pr-20220321' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux
Pull selinux updates from Paul Moore:
"We've got a number of SELinux patches queued up, the highlights are:
- Fixup the security_fs_context_parse_param() LSM hook so it executes
all of the LSM hook implementations unless a serious error occurs.
We also correct the SELinux hook implementation so that it returns
zero on success.
- In addition to a few SELinux mount option parsing fixes, we
simplified the parsing by moving it earlier in the process.
The logic was that it was unlikely an admin/user would use the new
mount API and not have the policy loaded before passing the SELinux
options.
- Properly fixed the LSM/SELinux/SCTP hooks with the addition of the
security_sctp_assoc_established() hook.
This work was done in conjunction with the netdev folks and should
complete the move of the SCTP labeling from the endpoints to the
associations.
- Fixed a variety of sparse warnings caused by changes in the "__rcu"
markings of some core kernel structures.
- Ensure we access the superblock's LSM security blob using the
stacking-safe accessors.
- Added the ability for the kernel to always allow FIOCLEX and
FIONCLEX if the "ioctl_skip_cloexec" policy capability is
specified.
- Various constifications improvements, type casting improvements,
additional return value checks, and dead code/parameter removal.
- Documentation fixes"
* tag 'selinux-pr-20220321' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux: (23 commits)
selinux: shorten the policy capability enum names
docs: fix 'make htmldocs' warning in SCTP.rst
selinux: allow FIOCLEX and FIONCLEX with policy capability
selinux: use correct type for context length
selinux: drop return statement at end of void functions
security: implement sctp_assoc_established hook in selinux
security: add sctp_assoc_established hook
selinux: parse contexts for mount options early
selinux: various sparse fixes
selinux: try to use preparsed sid before calling parse_sid()
selinux: Fix selinux_sb_mnt_opts_compat()
LSM: general protection fault in legacy_parse_param
selinux: fix a type cast problem in cred_init_security()
selinux: drop unused macro
selinux: simplify cred_init_security
selinux: do not discard const qualifier in cast
selinux: drop unused parameter of avtab_insert_node
selinux: drop cast to same type
selinux: enclose macro arguments in parenthesis
selinux: declare name parameter of hash_eval const
...
Those return statements at the end of a void function are redundant.
Reported by clang-tidy [readability-redundant-control-flow]
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
On error path from cond_read_list() and duplicate_policydb_cond_list()
the cond_list_destroy() gets called a second time in caller functions,
resulting in NULL pointer deref. Fix this by resetting the
cond_list_len to 0 in cond_list_destroy(), making subsequent calls a
noop.
Also consistently reset the cond_list pointer to NULL after freeing.
Cc: stable@vger.kernel.org
Signed-off-by: Vratislav Bendel <vbendel@redhat.com>
[PM: fix line lengths in the description]
Signed-off-by: Paul Moore <paul@paul-moore.com>
The macro _DEBUG_HASHES is nowhere used. The configuration DEBUG_HASHES
enables debugging of the SELinux hash tables, but the with an underscore
prefixed macro definition has no direct impact or any documentation.
Reported by clang [-Wunused-macros]
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The parameter cur is not used in avtab_insert_node().
Reported by clang [-Wunused-parameter]
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Both the lvalue scontextp and rvalue scontext are of the type char*.
Drop the redundant explicit cast not needed since commit 9a59daa03d
("SELinux: fix sleeping allocation in security_context_to_sid"), where
the type of scontext changed from const char* to char*.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Enclose the macro arguments in parenthesis to avoid potential evaluation
order issues.
Note the xperm and ebitmap macros are still not side-effect safe due to
double evaluation.
Reported by clang-tidy [bugprone-macro-parentheses]
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
String literals are passed as second argument to hash_eval(). Also the
parameter is already declared const in the DEBUG_HASHES configuration.
Reported by clang [-Wwrite-strings]:
security/selinux/ss/policydb.c:1881:26: error: passing
'const char [8]' to parameter of type 'char *' discards
qualifiers
hash_eval(&p->range_tr, rangetr);
^~~~~~~~~
security/selinux/ss/policydb.c:707:55: note: passing argument to
parameter 'hash_name' here
static inline void hash_eval(struct hashtab *h, char *hash_name)
^
security/selinux/ss/policydb.c:2099:32: error: passing
'const char [11]' to parameter of type 'char *' discards
qualifiers
hash_eval(&p->filename_trans, filenametr);
^~~~~~~~~~~~
security/selinux/ss/policydb.c:707:55: note: passing argument to
parameter 'hash_name' here
static inline void hash_eval(struct hashtab *h, char *hash_name)
^
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: line wrapping in description]
Signed-off-by: Paul Moore <paul@paul-moore.com>
The path parameter is only read from in security_genfs_sid(),
selinux_policy_genfs_sid() and __security_genfs_sid(). Since a string
literal is passed as argument, declare the parameter const.
Also align the parameter names in the declaration and definition.
Reported by clang [-Wwrite-strings]:
security/selinux/hooks.c:553:60: error: passing 'const char [2]'
to parameter of type 'char *' discards qualifiers
[-Wincompatible-pointer-types-discards-qualifiers]
rc = security_genfs_sid(&selinux_state, ... , /,
^~~
./security/selinux/include/security.h:389:36: note: passing
argument to parameter 'name' here
const char *fstype, char *name, u16 sclass,
^
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: wrapped description]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Merge tag 'selinux-pr-20220110' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux
Pull selinux updates from Paul Moore:
"Nothing too significant, but five SELinux patches for v5.17 that do
the following:
- Harden the code through additional use of the struct_size() macro
- Plug some memory leaks
- Clean up the code via removal of the security_add_mnt_opt() LSM
hook and minor tweaks to selinux_add_opt()
- Rename security_task_getsecid_subj() to better reflect its actual
behavior/use - now called security_current_getsecid_subj()"
* tag 'selinux-pr-20220110' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
selinux: minor tweaks to selinux_add_opt()
selinux: fix potential memleak in selinux_add_opt()
security,selinux: remove security_add_mnt_opt()
selinux: Use struct_size() helper in kmalloc()
lsm: security_task_getsecid_subj() -> security_current_getsecid_subj()
Make use of struct_size() helper instead of an open-coded calculation.
Link: https://github.com/KSPP/linux/issues/160
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
When the hash table slot array allocation fails in hashtab_init(),
h->size is left initialized with a non-zero value, but the h->htable
pointer is NULL. This may then cause a NULL pointer dereference, since
the policydb code relies on the assumption that even after a failed
hashtab_init(), hashtab_map() and hashtab_destroy() can be safely called
on it. Yet, these detect an empty hashtab only by looking at the size.
Fix this by making sure that hashtab_init() always leaves behind a valid
empty hashtab when the allocation fails.
Cc: stable@vger.kernel.org
Fixes: 03414a49ad ("selinux: do not allocate hashtabs dynamically")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
There were a number of places in the code where the function
definition did not match the associated comment block as well
at least one file where the appropriate header files were not
included (missing function declaration/prototype); this patch
fixes all of these issue such that building the SELinux code
with "W=1" is now warning free.
% make W=1 security/selinux/
Signed-off-by: Paul Moore <paul@paul-moore.com>
Current code contains a lot of racy patterns when converting an
ocontext's context structure to an SID. This is being done in a "lazy"
fashion, such that the SID is looked up in the SID table only when it's
first needed and then cached in the "sid" field of the ocontext
structure. However, this is done without any locking or memory barriers
and is thus unsafe.
Between commits 24ed7fdae6 ("selinux: use separate table for initial
SID lookup") and 66f8e2f03c ("selinux: sidtab reverse lookup hash
table"), this race condition lead to an actual observable bug, because a
pointer to the shared sid field was passed directly to
sidtab_context_to_sid(), which was using this location to also store an
intermediate value, which could have been read by other threads and
interpreted as an SID. In practice this caused e.g. new mounts to get a
wrong (seemingly random) filesystem context, leading to strange denials.
This bug has been spotted in the wild at least twice, see [1] and [2].
Fix the race condition by making all the racy functions use a common
helper that ensures the ocontext::sid accesses are made safely using the
appropriate SMP constructs.
Note that security_netif_sid() was populating the sid field of both
contexts stored in the ocontext, but only the first one was actually
used. The SELinux wiki's documentation on the "netifcon" policy
statement [3] suggests that using only the first context is intentional.
I kept only the handling of the first context here, as there is really
no point in doing the SID lookup for the unused one.
I wasn't able to reproduce the bug mentioned above on any kernel that
includes commit 66f8e2f03c, even though it has been reported that the
issue occurs with that commit, too, just less frequently. Thus, I wasn't
able to verify that this patch fixes the issue, but it makes sense to
avoid the race condition regardless.
[1] https://github.com/containers/container-selinux/issues/89
[2] https://lists.fedoraproject.org/archives/list/selinux@lists.fedoraproject.org/thread/6DMTAMHIOAOEMUAVTULJD45JZU7IBAFM/
[3] https://selinuxproject.org/page/NetworkStatements#netifcon
Cc: stable@vger.kernel.org
Cc: Xinjie Zheng <xinjie@google.com>
Reported-by: Sujithra Periasamy <sujithra@google.com>
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Pull selinux update from Paul Moore:
"We've got an unusually small SELinux pull request for v5.15 that
consists of only one (?!) patch that is really pretty minor when you
look at it.
Unsurprisingly it passes all of our tests and merges cleanly on top of
your tree right now, please merge this for v5.15"
* tag 'selinux-pr-20210830' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
selinux: return early for possible NULL audit buffers
It should not return 0 when SID 0 is assigned to isids.
This patch fixes it.
Cc: stable@vger.kernel.org
Fixes: e3e0b582c3 ("selinux: remove unused initial SIDs and improve handling")
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
[PM: remove changelog from description]
Signed-off-by: Paul Moore <paul@paul-moore.com>
audit_log_start() may return NULL in below cases:
- when audit is not initialized.
- when audit backlog limit exceeds.
After the call to audit_log_start() is made and then possible NULL audit
buffer argument is passed to audit_log_*() functions,
audit_log_*() functions return immediately in case of a NULL audit buffer
argument.
But it is optimal to return early when audit_log_start() returns NULL,
because it is not necessary for audit_log_*() functions to be called with
NULL audit buffer argument.
So add exception handling for possible NULL audit buffers where
return value can be handled from callers.
Signed-off-by: Austin Kim <austin.kim@lge.com>
[PM: tweak subject line]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Fix function name and add comment for parameter state in ss/services.c
kernel-doc to remove some warnings found by running make W=1 LLVM=1.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Variable rc is set to '-EINVAL' but this value is never read as
it is overwritten or not used later on, hence it is a redundant
assignment and can be removed.
Cleans up the following clang-analyzer warning:
security/selinux/ss/services.c:2103:3: warning: Value stored to 'rc' is
never read [clang-analyzer-deadcode.DeadStores].
security/selinux/ss/services.c:2079:2: warning: Value stored to 'rc' is
never read [clang-analyzer-deadcode.DeadStores].
security/selinux/ss/services.c:2071:2: warning: Value stored to 'rc' is
never read [clang-analyzer-deadcode.DeadStores].
security/selinux/ss/services.c:2062:2: warning: Value stored to 'rc' is
never read [clang-analyzer-deadcode.DeadStores].
security/selinux/ss/policydb.c:2592:3: warning: Value stored to 'rc' is
never read [clang-analyzer-deadcode.DeadStores].
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
We can do the allocation + copying of expr.nodes in one go using
kmemdup().
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Merge tag 'landlock_v34' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull Landlock LSM from James Morris:
"Add Landlock, a new LSM from Mickaël Salaün.
Briefly, Landlock provides for unprivileged application sandboxing.
From Mickaël's cover letter:
"The goal of Landlock is to enable to restrict ambient rights (e.g.
global filesystem access) for a set of processes. Because Landlock
is a stackable LSM [1], it makes possible to create safe security
sandboxes as new security layers in addition to the existing
system-wide access-controls. This kind of sandbox is expected to
help mitigate the security impact of bugs or unexpected/malicious
behaviors in user-space applications. Landlock empowers any
process, including unprivileged ones, to securely restrict
themselves.
Landlock is inspired by seccomp-bpf but instead of filtering
syscalls and their raw arguments, a Landlock rule can restrict the
use of kernel objects like file hierarchies, according to the
kernel semantic. Landlock also takes inspiration from other OS
sandbox mechanisms: XNU Sandbox, FreeBSD Capsicum or OpenBSD
Pledge/Unveil.
In this current form, Landlock misses some access-control features.
This enables to minimize this patch series and ease review. This
series still addresses multiple use cases, especially with the
combined use of seccomp-bpf: applications with built-in sandboxing,
init systems, security sandbox tools and security-oriented APIs [2]"
The cover letter and v34 posting is here:
https://lore.kernel.org/linux-security-module/20210422154123.13086-1-mic@digikod.net/
See also:
https://landlock.io/
This code has had extensive design discussion and review over several
years"
Link: https://lore.kernel.org/lkml/50db058a-7dde-441b-a7f9-f6837fe8b69f@schaufler-ca.com/ [1]
Link: https://lore.kernel.org/lkml/f646e1c7-33cf-333f-070c-0a40ad0468cd@digikod.net/ [2]
* tag 'landlock_v34' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
landlock: Enable user space to infer supported features
landlock: Add user and kernel documentation
samples/landlock: Add a sandbox manager example
selftests/landlock: Add user space tests
landlock: Add syscall implementations
arch: Wire up Landlock syscalls
fs,security: Add sb_delete hook
landlock: Support filesystem access-control
LSM: Infrastructure management of the superblock
landlock: Add ptrace restrictions
landlock: Set up the security framework and manage credentials
landlock: Add ruleset and domain management
landlock: Add object management
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Merge tag 'selinux-pr-20210426' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux
Pull selinux updates from Paul Moore:
- Add support for measuring the SELinux state and policy capabilities
using IMA.
- A handful of SELinux/NFS patches to compare the SELinux state of one
mount with a set of mount options. Olga goes into more detail in the
patch descriptions, but this is important as it allows more
flexibility when using NFS and SELinux context mounts.
- Properly differentiate between the subjective and objective LSM
credentials; including support for the SELinux and Smack. My clumsy
attempt at a proper fix for AppArmor didn't quite pass muster so John
is working on a proper AppArmor patch, in the meantime this set of
patches shouldn't change the behavior of AppArmor in any way. This
change explains the bulk of the diffstat beyond security/.
- Fix a problem where we were not properly terminating the permission
list for two SELinux object classes.
* tag 'selinux-pr-20210426' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
selinux: add proper NULL termination to the secclass_map permissions
smack: differentiate between subjective and objective task credentials
selinux: clarify task subjective and objective credentials
lsm: separate security_task_getsecid() into subjective and objective variants
nfs: account for selinux security context when deciding to share superblock
nfs: remove unneeded null check in nfs_fill_super()
lsm,selinux: add new hook to compare new mount to an existing mount
selinux: fix misspellings using codespell tool
selinux: fix misspellings using codespell tool
selinux: measure state and policy capabilities
selinux: Allow context mounts for unpriviliged overlayfs
Move management of the superblock->sb_security blob out of the
individual security modules and into the security infrastructure.
Instead of allocating the blobs from within the modules, the modules
tell the infrastructure how much space is required, and the space is
allocated there.
Cc: John Johansen <john.johansen@canonical.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com>
Reviewed-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210422154123.13086-6-mic@digikod.net
Signed-off-by: James Morris <jamorris@linux.microsoft.com>
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Merge tag 'selinux-pr-20210409' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux
Pull selinux fixes from Paul Moore:
"Three SELinux fixes.
These fix known problems relating to (re)loading SELinux policy or
changing the policy booleans, and pass our test suite without problem"
* tag 'selinux-pr-20210409' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
selinux: fix race between old and new sidtab
selinux: fix cond_list corruption when changing booleans
selinux: make nslot handling in avtab more robust
Since commit 1b8b31a2e6 ("selinux: convert policy read-write lock to
RCU"), there is a small window during policy load where the new policy
pointer has already been installed, but some threads may still be
holding the old policy pointer in their read-side RCU critical sections.
This means that there may be conflicting attempts to add a new SID entry
to both tables via sidtab_context_to_sid().
See also (and the rest of the thread):
https://lore.kernel.org/selinux/CAFqZXNvfux46_f8gnvVvRYMKoes24nwm2n3sPbMjrB8vKTW00g@mail.gmail.com/
Fix this by installing the new policy pointer under the old sidtab's
spinlock along with marking the old sidtab as "frozen". Then, if an
attempt to add new entry to a "frozen" sidtab is detected, make
sidtab_context_to_sid() return -ESTALE to indicate that a new policy
has been installed and that the caller will have to abort the policy
transaction and try again after re-taking the policy pointer (which is
guaranteed to be a newer policy). This requires adding a retry-on-ESTALE
logic to all callers of sidtab_context_to_sid(), but fortunately these
are easy to determine and aren't that many.
This seems to be the simplest solution for this problem, even if it
looks somewhat ugly. Note that other places in the kernel (e.g.
do_mknodat() in fs/namei.c) use similar stale-retry patterns, so I think
it's reasonable.
Cc: stable@vger.kernel.org
Fixes: 1b8b31a2e6 ("selinux: convert policy read-write lock to RCU")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Currently, duplicate_policydb_cond_list() first copies the whole
conditional avtab and then tries to link to the correct entries in
cond_dup_av_list() using avtab_search(). However, since the conditional
avtab may contain multiple entries with the same key, this approach
often fails to find the right entry, potentially leading to wrong rules
being activated/deactivated when booleans are changed.
To fix this, instead start with an empty conditional avtab and add the
individual entries one-by-one while building the new av_lists. This
approach leads to the correct result, since each entry is present in the
av_lists exactly once.
The issue can be reproduced with Fedora policy as follows:
# sesearch -s ftpd_t -t public_content_rw_t -c dir -p create -A
allow ftpd_t non_security_file_type:dir { add_name create getattr ioctl link lock open read remove_name rename reparent rmdir search setattr unlink watch watch_reads write }; [ ftpd_full_access ]:True
allow ftpd_t public_content_rw_t:dir { add_name create link remove_name rename reparent rmdir setattr unlink watch watch_reads write }; [ ftpd_anon_write ]:True
# setsebool ftpd_anon_write=off ftpd_connect_all_unreserved=off ftpd_connect_db=off ftpd_full_access=off
On fixed kernels, the sesearch output is the same after the setsebool
command:
# sesearch -s ftpd_t -t public_content_rw_t -c dir -p create -A
allow ftpd_t non_security_file_type:dir { add_name create getattr ioctl link lock open read remove_name rename reparent rmdir search setattr unlink watch watch_reads write }; [ ftpd_full_access ]:True
allow ftpd_t public_content_rw_t:dir { add_name create link remove_name rename reparent rmdir setattr unlink watch watch_reads write }; [ ftpd_anon_write ]:True
While on the broken kernels, it will be different:
# sesearch -s ftpd_t -t public_content_rw_t -c dir -p create -A
allow ftpd_t non_security_file_type:dir { add_name create getattr ioctl link lock open read remove_name rename reparent rmdir search setattr unlink watch watch_reads write }; [ ftpd_full_access ]:True
allow ftpd_t non_security_file_type:dir { add_name create getattr ioctl link lock open read remove_name rename reparent rmdir search setattr unlink watch watch_reads write }; [ ftpd_full_access ]:True
allow ftpd_t non_security_file_type:dir { add_name create getattr ioctl link lock open read remove_name rename reparent rmdir search setattr unlink watch watch_reads write }; [ ftpd_full_access ]:True
While there, also simplify the computation of nslots. This changes the
nslots values for nrules 2 or 3 to just two slots instead of 4, which
makes the sequence more consistent.
Cc: stable@vger.kernel.org
Fixes: c7c556f1e8 ("selinux: refactor changing booleans")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
1. Make sure all fileds are initialized in avtab_init().
2. Slightly refactor avtab_alloc() to use the above fact.
3. Use h->nslot == 0 as a sentinel in the access functions to prevent
dereferencing h->htable when it's not allocated.
Cc: stable@vger.kernel.org
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Merge tag 'selinux-pr-20210322' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux
Pull selinux fixes from Paul Moore:
"Three SELinux patches:
- Fix a problem where a local variable is used outside its associated
function. Thankfully this can only be triggered by reloading the
SELinux policy, which is a restricted operation for other obvious
reasons.
- Fix some incorrect, and inconsistent, audit and printk messages
when loading the SELinux policy.
All three patches are relatively minor and have been through our
testing with no failures"
* tag 'selinux-pr-20210322' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
selinuxfs: unify policy load error reporting
selinux: fix variable scope issue in live sidtab conversion
selinux: don't log MAC_POLICY_LOAD record on failed policy load
Commit 02a52c5c8c ("selinux: move policy commit after updating
selinuxfs") moved the selinux_policy_commit() call out of
security_load_policy() into sel_write_load(), which caused a subtle yet
rather serious bug.
The problem is that security_load_policy() passes a reference to the
convert_params local variable to sidtab_convert(), which stores it in
the sidtab, where it may be accessed until the policy is swapped over
and RCU synchronized. Before 02a52c5c8c, selinux_policy_commit() was
called directly from security_load_policy(), so the convert_params
pointer remained valid all the way until the old sidtab was destroyed,
but now that's no longer the case and calls to sidtab_context_to_sid()
on the old sidtab after security_load_policy() returns may cause invalid
memory accesses.
This can be easily triggered using the stress test from commit
ee1a84fdfe ("selinux: overhaul sidtab to fix bug and improve
performance"):
```
function rand_cat() {
echo $(( $RANDOM % 1024 ))
}
function do_work() {
while true; do
echo -n "system_u:system_r:kernel_t:s0:c$(rand_cat),c$(rand_cat)" \
>/sys/fs/selinux/context 2>/dev/null || true
done
}
do_work >/dev/null &
do_work >/dev/null &
do_work >/dev/null &
while load_policy; do echo -n .; sleep 0.1; done
kill %1
kill %2
kill %3
```
Fix this by allocating the temporary sidtab convert structures
dynamically and passing them among the
selinux_policy_{load,cancel,commit} functions.
Fixes: 02a52c5c8c ("selinux: move policy commit after updating selinuxfs")
Cc: stable@vger.kernel.org
Tested-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
[PM: merge fuzz in security.h and services.c]
Signed-off-by: Paul Moore <paul@paul-moore.com>
A typo is found out by codespell tool in 16th line of hashtab.c
$ codespell ./security/selinux/ss/
./hashtab.c:16: rouding ==> rounding
Fix a typo found by codespell.
Signed-off-by: Xiong Zhenwu <xiong.zhenwu@zte.com.cn>
[PM: subject line tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
SELinux stores the configuration state and the policy capabilities
in kernel memory. Changes to this data at runtime would have an impact
on the security guarantees provided by SELinux. Measuring this data
through IMA subsystem provides a tamper-resistant way for
an attestation service to remotely validate it at runtime.
Measure the configuration state and policy capabilities by calling
the IMA hook ima_measure_critical_data().
To enable SELinux data measurement, the following steps are required:
1, Add "ima_policy=critical_data" to the kernel command line arguments
to enable measuring SELinux data at boot time.
For example,
BOOT_IMAGE=/boot/vmlinuz-5.11.0-rc3+ root=UUID=fd643309-a5d2-4ed3-b10d-3c579a5fab2f ro nomodeset security=selinux ima_policy=critical_data
2, Add the following rule to /etc/ima/ima-policy
measure func=CRITICAL_DATA label=selinux
Sample measurement of SELinux state and policy capabilities:
10 2122...65d8 ima-buf sha256:13c2...1292 selinux-state 696e...303b
Execute the following command to extract the measured data
from the IMA's runtime measurements list:
grep "selinux-state" /sys/kernel/security/integrity/ima/ascii_runtime_measurements | tail -1 | cut -d' ' -f 6 | xxd -r -p
The output should be a list of key-value pairs. For example,
initialized=1;enforcing=0;checkreqprot=1;network_peer_controls=1;open_perms=1;extended_socket_class=1;always_check_network=0;cgroup_seclabel=1;nnp_nosuid_transition=1;genfs_seclabel_symlinks=0;
To verify the measurement is consistent with the current SELinux state
reported on the system, compare the integer values in the following
files with those set in the IMA measurement (using the following commands):
- cat /sys/fs/selinux/enforce
- cat /sys/fs/selinux/checkreqprot
- cat /sys/fs/selinux/policy_capabilities/[capability_file]
Note that the actual verification would be against an expected state
and done on a separate system (likely an attestation server) requiring
"initialized=1;enforcing=1;checkreqprot=0;"
for a secure state and then whatever policy capabilities are actually
set in the expected policy (which can be extracted from the policy
itself via seinfo, for example).
Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Suggested-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Suggested-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Merge tag 'integrity-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity
Pull IMA updates from Mimi Zohar:
"New is IMA support for measuring kernel critical data, as per usual
based on policy. The first example measures the in memory SELinux
policy. The second example measures the kernel version.
In addition are four bug fixes to address memory leaks and a missing
'static' function declaration"
* tag 'integrity-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
integrity: Make function integrity_add_key() static
ima: Free IMA measurement buffer after kexec syscall
ima: Free IMA measurement buffer on error
IMA: Measure kernel version in early boot
selinux: include a consumer of the new IMA critical data hook
IMA: define a builtin critical data measurement policy
IMA: extend critical data hook to limit the measurement based on a label
IMA: limit critical data measurement based on a label
IMA: add policy rule to measure critical data
IMA: define a hook to measure kernel integrity critical data
IMA: add support to measure buffer data hash
IMA: generalize keyring specific measurement constructs
evm: Fix memleak in init_desc
SELinux stores the active policy in memory, so the changes to this data
at runtime would have an impact on the security guarantees provided
by SELinux. Measuring in-memory SELinux policy through IMA subsystem
provides a secure way for the attestation service to remotely validate
the policy contents at runtime.
Measure the hash of the loaded policy by calling the IMA hook
ima_measure_critical_data(). Since the size of the loaded policy
can be large (several MB), measure the hash of the policy instead of
the entire policy to avoid bloating the IMA log entry.
To enable SELinux data measurement, the following steps are required:
1, Add "ima_policy=critical_data" to the kernel command line arguments
to enable measuring SELinux data at boot time.
For example,
BOOT_IMAGE=/boot/vmlinuz-5.10.0-rc1+ root=UUID=fd643309-a5d2-4ed3-b10d-3c579a5fab2f ro nomodeset security=selinux ima_policy=critical_data
2, Add the following rule to /etc/ima/ima-policy
measure func=CRITICAL_DATA label=selinux
Sample measurement of the hash of SELinux policy:
To verify the measured data with the current SELinux policy run
the following commands and verify the output hash values match.
sha256sum /sys/fs/selinux/policy | cut -d' ' -f 1
grep "selinux-policy-hash" /sys/kernel/security/integrity/ima/ascii_runtime_measurements | tail -1 | cut -d' ' -f 6
Note that the actual verification of SELinux policy would require loading
the expected policy into an identical kernel on a pristine/known-safe
system and run the sha256sum /sys/kernel/selinux/policy there to get
the expected hash.
Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Suggested-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
All of these are never modified outside initcalls, so they can be
__ro_after_init.
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Its value is actually not changed anywhere, so it can be substituted for
a direct call to audit_update_lsm_rules().
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This allows for dontauditing very specific ioctls e.g. TCGETS without
dontauditing every ioctl or granting additional permissions.
Now either an allowx, dontauditx or auditallowx rules enables checking
for extended permissions.
Signed-off-by: Jonathan Hettwer <j2468h@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Merge tag 'selinux-pr-20201012' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux
Pull selinux updates from Paul Moore:
"A decent number of SELinux patches for v5.10, twenty two in total. The
highlights are listed below, but all of the patches pass our test
suite and merge cleanly.
- A number of changes to how the SELinux policy is loaded and managed
inside the kernel with the goal of improving the atomicity of a
SELinux policy load operation.
These changes account for the bulk of the diffstat as well as the
patch count. A special thanks to everyone who contributed patches
and fixes for this work.
- Convert the SELinux policy read-write lock to RCU.
- A tracepoint was added for audited SELinux access control events;
this should help provide a more unified backtrace across kernel and
userspace.
- Allow the removal of security.selinux xattrs when a SELinux policy
is not loaded.
- Enable policy capabilities in SELinux policies created with the
scripts/selinux/mdp tool.
- Provide some "no sooner than" dates for the SELinux checkreqprot
sysfs deprecation"
* tag 'selinux-pr-20201012' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux: (22 commits)
selinux: provide a "no sooner than" date for the checkreqprot removal
selinux: Add helper functions to get and set checkreqprot
selinux: access policycaps with READ_ONCE/WRITE_ONCE
selinux: simplify away security_policydb_len()
selinux: move policy mutex to selinux_state, use in lockdep checks
selinux: fix error handling bugs in security_load_policy()
selinux: convert policy read-write lock to RCU
selinux: delete repeated words in comments
selinux: add basic filtering for audit trace events
selinux: add tracepoint on audited events
selinux: Create new booleans and class dirs out of tree
selinux: Standardize string literal usage for selinuxfs directory names
selinux: Refactor selinuxfs directory populating functions
selinux: Create function for selinuxfs directory cleanup
selinux: permit removing security.selinux xattr before policy load
selinux: fix memdup.cocci warnings
selinux: avoid dereferencing the policy prior to initialization
selinux: fix allocation failure check on newpolicy->sidtab
selinux: refactor changing booleans
selinux: move policy commit after updating selinuxfs
...
Use READ_ONCE/WRITE_ONCE for all accesses to the
selinux_state.policycaps booleans to prevent compiler
mischief.
Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
