Commit Graph

305 Commits

Author SHA1 Message Date
Linus Torvalds
8b45c6c90a + Features
- improve debug printing
   - carry mediation check on label (optimization)
   - improve ability for compiler to optimize __begin_current_label_crit_section
   - transition for a linked list of rulesets to a vector of rulesets
   - don't hardcode profile signal, allow it to be set by policy
   - ability to mediate caps via the state machine instead of lut
   - Add Ubuntu af_unix mediation, put it behind new v9 abi
 
 + Cleanups
   - fix typos and spelling errors
   - cleanup kernel doc and code inconsistencies
   - remove redundant checks/code
   - remove unused variables
   - Use str_yes_no() helper function
   - mark tables static where appropriate
   - make all generated string array headers const char *const
   - refactor to doc semantics of file_perm checks
   - replace macro calls to network/socket fns with explicit calls
   - refactor/cleanup socket mediation code preparing for finer grained
     mediation of different network families
   - several updates to kernel doc comments
 
 + Bug fixes
   - apparmor: Fix incorrect profile->signal range check
   - idmap mount fixes
   - policy unpack unaligned access fixes
   - kfree_sensitive() where appropriate
   - fix oops when freeing policy
   - fix conflicting attachment resolution
   - fix exec table look-ups when stacking isn't first
   - fix exec auditing
   - mitigate userspace generating overly large xtables
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Merge tag 'apparmor-pr-2025-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor

Pull apparmor updates from John Johansen:
 "This has one major feature, it pulls in a cleaned up version of
  af_unix mediation that Ubuntu has been carrying for years. It is
  placed behind a new abi to ensure that it does cause policy
  regressions. With pulling in the af_unix mediation there have been
  cleanups and some refactoring of network socket mediation. This
  accounts for the majority of the changes in the diff.

  In addition there are a few improvements providing minor code
  optimizations. several code cleanups, and bug fixes.

  Features:
   - improve debug printing
   - carry mediation check on label (optimization)
   - improve ability for compiler to optimize
     __begin_current_label_crit_section
   - transition for a linked list of rulesets to a vector of rulesets
   - don't hardcode profile signal, allow it to be set by policy
   - ability to mediate caps via the state machine instead of lut
   - Add Ubuntu af_unix mediation, put it behind new v9 abi

  Cleanups:
   - fix typos and spelling errors
   - cleanup kernel doc and code inconsistencies
   - remove redundant checks/code
   - remove unused variables
   - Use str_yes_no() helper function
   - mark tables static where appropriate
   - make all generated string array headers const char *const
   - refactor to doc semantics of file_perm checks
   - replace macro calls to network/socket fns with explicit calls
   - refactor/cleanup socket mediation code preparing for finer grained
     mediation of different network families
   - several updates to kernel doc comments

  Bug fixes:
   - fix incorrect profile->signal range check
   - idmap mount fixes
   - policy unpack unaligned access fixes
   - kfree_sensitive() where appropriate
   - fix oops when freeing policy
   - fix conflicting attachment resolution
   - fix exec table look-ups when stacking isn't first
   - fix exec auditing
   - mitigate userspace generating overly large xtables"

* tag 'apparmor-pr-2025-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor: (60 commits)
  apparmor: fix: oops when trying to free null ruleset
  apparmor: fix Regression on linux-next (next-20250721)
  apparmor: fix test error: WARNING in apparmor_unix_stream_connect
  apparmor: Remove the unused variable rules
  apparmor: fix: accept2 being specifie even when permission table is presnt
  apparmor: transition from a list of rules to a vector of rules
  apparmor: fix documentation mismatches in val_mask_to_str and socket functions
  apparmor: remove redundant perms.allow MAY_EXEC bitflag set
  apparmor: fix kernel doc warnings for kernel test robot
  apparmor: Fix unaligned memory accesses in KUnit test
  apparmor: Fix 8-byte alignment for initial dfa blob streams
  apparmor: shift uid when mediating af_unix in userns
  apparmor: shift ouid when mediating hard links in userns
  apparmor: make sure unix socket labeling is correctly updated.
  apparmor: fix regression in fs based unix sockets when using old abi
  apparmor: fix AA_DEBUG_LABEL()
  apparmor: fix af_unix auditing to include all address information
  apparmor: Remove use of the double lock
  apparmor: update kernel doc comments for xxx_label_crit_section
  apparmor: make __begin_current_label_crit_section() indicate whether put is needed
  ...
2025-08-04 08:17:28 -07:00
John Johansen
9afdc6abb0 apparmor: transition from a list of rules to a vector of rules
The set of rules on a profile is not dynamically extended, instead
if a new ruleset is needed a new version of the profile is created.
This allows us to use a vector of rules instead of a list, slightly
reducing memory usage and simplifying the code.

Signed-off-by: John Johansen <john.johansen@canonical.com>
2025-07-20 02:31:06 -07:00
John Johansen
88fec3526e apparmor: make sure unix socket labeling is correctly updated.
When a unix socket is passed into a different confinement domain make
sure its cached mediation labeling is updated to correctly reflect
which domains are using the socket.

Fixes: c05e705812 ("apparmor: add fine grained af_unix mediation")
Signed-off-by: John Johansen <john.johansen@canonical.com>
2025-07-20 02:19:27 -07:00
John Johansen
6456ccbd2f apparmor: fix regression in fs based unix sockets when using old abi
Policy loaded using abi 7 socket mediation was not being applied
correctly in all cases. In some cases with fs based unix sockets a
subset of permissions where allowed when they should have been denied.

This was happening because the check for if the socket was an fs based
unix socket came before the abi check. But the abi check is where the
correct path is selected, so having the fs unix socket check occur
early would cause the wrong code path to be used.

Fix this by pushing the fs unix to be done after the abi check.

Fixes: dcd7a55941 ("apparmor: gate make fine grained unix mediation behind v9 abi")
Signed-off-by: John Johansen <john.johansen@canonical.com>
2025-07-15 22:39:43 -07:00
John Johansen
50d56a1a36 apparmor: fix AA_DEBUG_LABEL()
AA_DEBUG_LABEL() was not specifying it vargs, which is needed so it can
output debug parameters.

Fixes: 71e6cff3e0 ("apparmor: Improve debug print infrastructure")
Signed-off-by: John Johansen <john.johansen@canonical.com>
2025-07-15 22:39:43 -07:00
John Johansen
a30a9fdb66 apparmor: fix af_unix auditing to include all address information
The auditing of addresses currently doesn't include the source address
and mixes source and foreign/peer under the same audit name. Fix this
so source is always addr, and the foreign/peer is peer_addr.

Fixes: c05e705812 ("apparmor: add fine grained af_unix mediation")
Signed-off-by: John Johansen <john.johansen@canonical.com>
2025-07-15 22:39:43 -07:00
John Johansen
bc6e5f6933 apparmor: Remove use of the double lock
The use of the double lock is not necessary and problematic. Instead
pull the bits that need locks into their own sections and grab the
needed references.

Fixes: c05e705812 ("apparmor: add fine grained af_unix mediation")
Signed-off-by: John Johansen <john.johansen@canonical.com>
2025-07-15 22:39:43 -07:00
John Johansen
6afb0a7bc9 apparmor: update kernel doc comments for xxx_label_crit_section
Add a kernel doc header for __end_current_label_crit_section(), and
update the header for __begin_current_label_crit_section().

Fixes: b42ecc5f58ef ("apparmor: make __begin_current_label_crit_section() indicate whether put is needed")
Signed-off-by: John Johansen <john.johansen@canonical.com>
2025-07-15 22:39:43 -07:00
Mateusz Guzik
87cc7b0011 apparmor: make __begin_current_label_crit_section() indicate whether put is needed
Same as aa_get_newest_cred_label_condref().

This avoids a bunch of work overall and allows the compiler to note when no
clean up is necessary, allowing for tail calls.

This in particular happens in apparmor_file_permission(), which manages to
tail call aa_file_perm() 105 bytes in (vs a regular call 112 bytes in
followed by branches to figure out if clean up is needed).

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2025-07-15 22:39:43 -07:00
John Johansen
aff426f359 apparmor: mitigate parser generating large xtables
Some versions of the parser are generating an xtable transition per
state in the state machine, even when the state machine isn't using
the transition table.

The parser bug is triggered by
commit 2e12c5f060 ("apparmor: add additional flags to extended permission.")

In addition to fixing this in userspace, mitigate this in the kernel
as part of the policy verification checks by detecting this situation
and adjusting to what is actually used, or if not used at all freeing
it, so we are not wasting unneeded memory on policy.

Fixes: 2e12c5f060 ("apparmor: add additional flags to extended permission.")
Signed-off-by: John Johansen <john.johansen@canonical.com>
2025-07-15 22:39:07 -07:00
John Johansen
b1f87be728 apparmor: Document that label must be last member in struct aa_profile
The label struct is variable length. While its use in struct aa_profile
is fixed length at 2 entries the variable length member needs to be
the last member in the structure.

The code already does this but the comment has it in the wrong location.
Also add a comment to ensure it stays at the end of the structure.

While we are at it, update the documentation for other profile members
as well.

Signed-off-by: John Johansen <john.johansen@canonical.com>
2025-05-25 20:15:01 -07:00
Ryan Lee
a88db916b8 apparmor: fix loop detection used in conflicting attachment resolution
Conflicting attachment resolution is based on the number of states
traversed to reach an accepting state in the attachment DFA, accounting
for DFA loops traversed during the matching process. However, the loop
counting logic had multiple bugs:

 - The inc_wb_pos macro increments both position and length, but length
   is supposed to saturate upon hitting buffer capacity, instead of
   wrapping around.
 - If no revisited state is found when traversing the history, is_loop
   would still return true, as if there was a loop found the length of
   the history buffer, instead of returning false and signalling that
   no loop was found. As a result, the adjustment step of
   aa_dfa_leftmatch would sometimes produce negative counts with loop-
   free DFAs that traversed enough states.
 - The iteration in the is_loop for loop is supposed to stop before
   i = wb->len, so the conditional should be < instead of <=.

This patch fixes the above bugs as well as the following nits:
 - The count and size fields in struct match_workbuf were not used,
   so they can be removed.
 - The history buffer in match_workbuf semantically stores aa_state_t
   and not unsigned ints, even if aa_state_t is currently unsigned int.
 - The local variables in is_loop are counters, and thus should be
   unsigned ints instead of aa_state_t's.

Fixes: 21f6066105 ("apparmor: improve overlapping domain attachment resolution")

Signed-off-by: Ryan Lee <ryan.lee@canonical.com>
Co-developed-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2025-05-25 20:14:53 -07:00
Ryan Lee
6c055e6256 apparmor: ensure WB_HISTORY_SIZE value is a power of 2
WB_HISTORY_SIZE was defined to be a value not a power of 2, despite a
comment in the declaration of struct match_workbuf stating it is and a
modular arithmetic usage in the inc_wb_pos macro assuming that it is. Bump
WB_HISTORY_SIZE's value up to 32 and add a BUILD_BUG_ON_NOT_POWER_OF_2
line to ensure that any future changes to the value of WB_HISTORY_SIZE
respect this requirement.

Fixes: 136db99485 ("apparmor: increase left match history buffer size")

Signed-off-by: Ryan Lee <ryan.lee@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2025-05-17 18:20:10 -07:00
Randy Dunlap
a949b46e7d apparmor: fix some kernel-doc issues in header files
Fix kernel-doc warnings in apparmor header files as reported by
scripts/kernel-doc:

cred.h:128: warning: expecting prototype for end_label_crit_section(). Prototype was for end_current_label_crit_section() instead
file.h:108: warning: expecting prototype for aa_map_file_perms(). Prototype was for aa_map_file_to_perms() instead

lib.h:159: warning: Function parameter or struct member 'hname' not described in 'basename'
lib.h:159: warning: Excess function parameter 'name' description in 'basename'

match.h:21: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
 * The format used for transition tables is based on the GNU flex table

perms.h:109: warning: Function parameter or struct member 'accum' not described in 'aa_perms_accum_raw'
perms.h:109: warning: Function parameter or struct member 'addend' not described in 'aa_perms_accum_raw'
perms.h:136: warning: Function parameter or struct member 'accum' not described in 'aa_perms_accum'
perms.h:136: warning: Function parameter or struct member 'addend' not described in 'aa_perms_accum'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Ryan Lee <ryan.lee@canonical.com>
Cc: John Johansen <john.johansen@canonical.com>
Cc: John Johansen <john@apparmor.net>
Cc: apparmor@lists.ubuntu.com
Cc: linux-security-module@vger.kernel.org
Cc: Paul Moore <paul@paul-moore.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2025-05-17 01:52:25 -07:00
Mateusz Guzik
67e370aa7f apparmor: use the condition in AA_BUG_FMT even with debug disabled
This follows the established practice and fixes a build failure for me:
security/apparmor/file.c: In function ‘__file_sock_perm’:
security/apparmor/file.c:544:24: error: unused variable ‘sock’ [-Werror=unused-variable]
  544 |         struct socket *sock = (struct socket *) file->private_data;
      |                        ^~~~

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2025-02-10 11:17:59 -08:00
John Johansen
dcd7a55941 apparmor: gate make fine grained unix mediation behind v9 abi
Fine grained unix mediation in Ubuntu used ABI v7, and policy using
this has propogated onto systems where fine grained unix mediation was
not supported. The userspace policy compiler supports downgrading
policy so the policy could be shared without changes.

Unfortunately this had the side effect that policy was not updated for
the none Ubuntu systems and enabling fine grained unix mediation on
those systems means that a new kernel can break a system with existing
policy that worked with the previous kernel. With fine grained af_unix
mediation this regression can easily break the system causing boot to
fail, as it affect unix socket files, non-file based unix sockets, and
dbus communication.

To aoid this regression move fine grained af_unix mediation behind
a new abi. This means that the system's userspace and policy must
be updated to support the new policy before it takes affect and
dropping a new kernel on existing system will not result in a
regression.

The abi bump is done in such a way as existing policy can be activated
on the system by changing the policy abi declaration and existing unix
policy rules will apply. Policy then only needs to be incrementally
updated, can even be backported to existing Ubuntu policy.

Signed-off-by: John Johansen <john.johansen@canonical.com>
2025-01-18 06:47:13 -08:00
John Johansen
c05e705812 apparmor: add fine grained af_unix mediation
Extend af_unix mediation to support fine grained controls based on
the type (abstract, anonymous, fs), the address, and the labeling
on the socket.

This allows for using socket addresses to label and the socket and
control which subjects can communicate.

The unix rule format follows standard apparmor rules except that fs
based unix sockets can be mediated by existing file rules. None fs
unix sockets can be mediated by a unix socket rule. Where The address
of an abstract unix domain socket begins with the @ character, similar
to how they are reported (as paths) by netstat -x.  The address then
follows and may contain pattern matching and any characters including
the null character. In apparmor null characters must be specified by
using an escape sequence \000 or \x00. The pattern matching is the
same as is used by file path matching so * will not match / even
though it has no special meaning with in an abstract socket name. Eg.

     allow unix addr=@*,

Autobound unix domain sockets have a unix sun_path assigned to them by
the kernel, as such specifying a policy based address is not possible.
The autobinding of sockets can be controlled by specifying the special
auto keyword. Eg.

     allow unix addr=auto,

To indicate that the rule only applies to auto binding of unix domain
sockets.  It is important to note this only applies to the bind
permission as once the socket is bound to an address it is
indistinguishable from a socket that have an addr bound with a
specified name. When the auto keyword is used with other permissions
or as part of a peer addr it will be replaced with a pattern that can
match an autobound socket. Eg. For some kernels

    allow unix rw addr=auto,

It is important to note, this pattern may match abstract sockets that
were not autobound but have an addr that fits what is generated by the
kernel when autobinding a socket.

Anonymous unix domain sockets have no sun_path associated with the
socket address, however it can be specified with the special none
keyword to indicate the rule only applies to anonymous unix domain
sockets. Eg.

    allow unix addr=none,

If the address component of a rule is not specified then the rule
applies to autobind, abstract and anonymous sockets.

The label on the socket can be compared using the standard label=
rule conditional. Eg.

    allow unix addr=@foo peer=(label=bar),

see man apparmor.d for full syntax description.

Signed-off-by: John Johansen <john.johansen@canonical.com>
2025-01-18 06:47:12 -08:00
John Johansen
b4940d913c apparmor: in preparation for finer networking rules rework match_prot
Rework match_prot into a common fn that can be shared by all the
networking rules. This will provide compatibility with current socket
mediation, via the early bailout permission encoding.

Signed-off-by: John Johansen <john.johansen@canonical.com>
2025-01-18 06:47:12 -08:00
John Johansen
9045aa25d1 apparmor: remove af_select macro
The af_select macro just adds a layer of unnecessary abstraction that
makes following what the code is doing harder.

Signed-off-by: John Johansen <john.johansen@canonical.com>
2025-01-18 06:47:12 -08:00
John Johansen
ce9e3b3fa2 apparmor: add ability to mediate caps with policy state machine
Currently the caps encoding is very limited and can't be used with
conditionals. Allow capabilities to be mediated by the state
machine. This will allow us to add conditionals to capabilities that
aren't possible with the current encoding.

This patch only adds support for using the state machine and retains
the old encoding lookup as part of the runtime mediation code to
support older policy abis. A follow on patch will move backwards
compatibility to a mapping function done at policy load time.

Signed-off-by: John Johansen <john.johansen@canonical.com>
2025-01-18 06:47:12 -08:00
John Johansen
84c455decf apparmor: add support for profiles to define the kill signal
Previously apparmor has only sent SIGKILL but there are cases where
it can be useful to send a different signal. Allow the profile
to optionally specify a different value.

Signed-off-by: John Johansen <john.johansen@canonical.com>
2025-01-18 06:47:12 -08:00
John Johansen
2e12c5f060 apparmor: add additional flags to extended permission.
This is a step towards merging the file and policy state machines.

With the switch to extended permissions the state machine's ACCEPT2
table became unused freeing it up to store state specific flags. The
first flags to be stored are FLAG_OWNER and FLAG other which paves the
way towards merging the file and policydb perms into a single
permission table.

Currently Lookups based on the objects ownership conditional will
still need separate fns, this will be address in a following patch.

Signed-off-by: John Johansen <john.johansen@canonical.com>
2025-01-18 06:47:12 -08:00
John Johansen
de4754c801 apparmor: carry mediation check on label
In order to speed up the mediated check, precompute and store the
result as a bit per class type. This will not only allow us to
speed up the mediation check but is also a step to removing the
unconfined special cases as the unconfined check can be replaced
with the generic label_mediates() check.

Note: label check does not currently work for capabilities and resources
      which need to have their mediation updated first.

Signed-off-by: John Johansen <john.johansen@canonical.com>
2025-01-18 06:47:12 -08:00
John Johansen
71e6cff3e0 apparmor: Improve debug print infrastructure
Make it so apparmor debug output can be controlled by class flags
as well as the debug flag on labels. This provides much finer
control at what is being output so apparmor doesn't flood the
logs with information that is not needed, making it hard to find
what is important.

Signed-off-by: John Johansen <john.johansen@canonical.com>
2025-01-18 06:47:11 -08:00
Casey Schaufler
2d470c7781 lsm: replace context+len with lsm_context
Replace the (secctx,seclen) pointer pair with a single
lsm_context pointer to allow return of the LSM identifier
along with the context and context length. This allows
security_release_secctx() to know how to release the
context. Callers have been modified to use or save the
returned data from the new structure.

security_secid_to_secctx() and security_lsmproc_to_secctx()
will now return the length value on success instead of 0.

Cc: netdev@vger.kernel.org
Cc: audit@vger.kernel.org
Cc: netfilter-devel@vger.kernel.org
Cc: Todd Kjos <tkjos@google.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: subject tweak, kdoc fix, signedness fix from Dan Carpenter]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-12-04 14:42:31 -05:00
Casey Schaufler
6fba89813c lsm: ensure the correct LSM context releaser
Add a new lsm_context data structure to hold all the information about a
"security context", including the string, its size and which LSM allocated
the string. The allocation information is necessary because LSMs have
different policies regarding the lifecycle of these strings. SELinux
allocates and destroys them on each use, whereas Smack provides a pointer
to an entry in a list that never goes away.

Update security_release_secctx() to use the lsm_context instead of a
(char *, len) pair. Change its callers to do likewise.  The LSMs
supporting this hook have had comments added to remind the developer
that there is more work to be done.

The BPF security module provides all LSM hooks. While there has yet to
be a known instance of a BPF configuration that uses security contexts,
the possibility is real. In the existing implementation there is
potential for multiple frees in that case.

Cc: linux-integrity@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: audit@vger.kernel.org
Cc: netfilter-devel@vger.kernel.org
To: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: linux-nfs@vger.kernel.org
Cc: Todd Kjos <tkjos@google.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: subject tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-12-04 10:46:26 -05:00
John Johansen
9133493a76 parser: drop dead code for XXX_comb macros
The macros for label combination XXX_comb are no longer used and there
are no plans to use them so remove the dead code.

Signed-off-by: John Johansen <john.johansen@canonical.com>
2024-11-26 19:21:06 -08:00
Jinjie Ruan
2115517682 apparmor: Remove unused parameter L1 in macro next_comb
In the macro definition of next_comb(), a parameter L1 is accepted,
but it is not used. Hence, it should be removed.

Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2024-11-26 19:21:06 -08:00
Dr. David Alan Gilbert
75535669c9 apparmor: Remove deadcode
aa_label_audit, aa_label_find, aa_label_seq_print and aa_update_label_name
were added by commit
f1bd904175 ("apparmor: add the base fns() for domain labels")
but never used.

aa_profile_label_perm was added by commit
637f688dc3 ("apparmor: switch from profiles to using labels on contexts")
but never used.

aa_secid_update was added by commit
c092921219 ("apparmor: add support for mapping secids and using secctxes")
but never used.

aa_split_fqname has been unused since commit
3664268f19 ("apparmor: add namespace lookup fns()")

aa_lookup_profile has been unused since commit
93c98a484c ("apparmor: move exec domain mediation to using labels")

aa_audit_perms_cb was only used by aa_profile_label_perm (see above).

All of these commits are from around 2017.

Remove them.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2024-11-26 19:21:05 -08:00
John Johansen
9208c05f9f apparmor: add support for 2^24 states to the dfa state machine.
Currently the dfa state machine is limited by its default, next, and
check tables using u16. Allow loading of u32 tables, and if u16 tables
are loaded map them to u32.

The number of states allowed does not increase to 2^32 because the
base table uses the top 8 bits of its u32 for flags. Moving the flags
into a separate table allowing a full 2^32 bit range wil be done in
a separate patch.

Link: https://gitlab.com/apparmor/apparmor/-/issues/419
Signed-off-by: John Johansen <john.johansen@canonical.com>
2024-11-26 19:21:05 -08:00
Casey Schaufler
6f2f724f0e lsm: add lsmprop_to_secctx hook
Add a new hook security_lsmprop_to_secctx() and its LSM specific
implementations. The LSM specific code will use the lsm_prop element
allocated for that module. This allows for the possibility that more
than one module may be called upon to translate a secid to a string,
as can occur in the audit code.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: subject line tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-10-11 14:34:12 -04:00
Casey Schaufler
870b7fdc66 lsm: use lsm_prop in security_audit_rule_match
Change the secid parameter of security_audit_rule_match
to a lsm_prop structure pointer. Pass the entry from the
lsm_prop structure for the approprite slot to the LSM hook.

Change the users of security_audit_rule_match to use the
lsm_prop instead of a u32. The scaffolding function lsmprop_init()
fills the structure with the value of the old secid, ensuring that
it is available to the appropriate module hook. The sources of
the secid, security_task_getsecid() and security_inode_getsecid(),
will be converted to use the lsm_prop structure later in the series.
At that point the use of lsmprop_init() is dropped.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: subject line tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-10-11 14:34:12 -04:00
Casey Schaufler
2aff9d20d5 lsm: infrastructure management of the sock security
Move management of the sock->sk_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.

Acked-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: subject tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-07-29 16:54:50 -04:00
Linus Torvalds
ff30564411 apparmor-pr-2024-07-24 PR 2024-07-25
+ Cleanups
       - optimization: try to avoid refing the label in apparmor_file_open
       - remove useless static inline function is_deleted
       - use kvfree_sensitive to free data->data
       - fix typo in kernel doc
 
 + Bug fixes
       - unpack transition table if dfa is not present
       - test: add MODULE_DESCRIPTION()
       - take nosymfollow flag into account
       - fix possible NULL pointer dereference
       - fix null pointer deref when receiving skb during sock creation
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Merge tag 'apparmor-pr-2024-07-25' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor

Pull apparmor updates from John Johansen:
 "Cleanups
   - optimization: try to avoid refing the label in apparmor_file_open
   - remove useless static inline function is_deleted
   - use kvfree_sensitive to free data->data
   - fix typo in kernel doc

  Bug fixes:
   - unpack transition table if dfa is not present
   - test: add MODULE_DESCRIPTION()
   - take nosymfollow flag into account
   - fix possible NULL pointer dereference
   - fix null pointer deref when receiving skb during sock creation"

* tag 'apparmor-pr-2024-07-25' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor:
  apparmor: unpack transition table if dfa is not present
  apparmor: try to avoid refing the label in apparmor_file_open
  apparmor: test: add MODULE_DESCRIPTION()
  apparmor: take nosymfollow flag into account
  apparmor: fix possible NULL pointer dereference
  apparmor: fix typo in kernel doc
  apparmor: remove useless static inline function is_deleted
  apparmor: use kvfree_sensitive to free data->data
  apparmor: Fix null pointer deref when receiving skb during sock creation
2024-07-27 13:28:39 -07:00
Mateusz Guzik
f4fee216df apparmor: try to avoid refing the label in apparmor_file_open
If the label is not stale (which is the common case), the fact that the
passed file object holds a reference can be leverged to avoid the
ref/unref cycle. Doing so reduces performance impact of apparmor on
parallel open() invocations.

When benchmarking on a 24-core vm using will-it-scale's open1_process
("Separate file open"), the results are (ops/s):
before: 6092196
after:  8309726 (+36%)

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2024-07-24 11:05:14 -07:00
GUO Zihua
9a95c5bfbf ima: Avoid blocking in RCU read-side critical section
A panic happens in ima_match_policy:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
PGD 42f873067 P4D 0
Oops: 0000 [#1] SMP NOPTI
CPU: 5 PID: 1286325 Comm: kubeletmonit.sh
Kdump: loaded Tainted: P
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
               BIOS 0.0.0 02/06/2015
RIP: 0010:ima_match_policy+0x84/0x450
Code: 49 89 fc 41 89 cf 31 ed 89 44 24 14 eb 1c 44 39
      7b 18 74 26 41 83 ff 05 74 20 48 8b 1b 48 3b 1d
      f2 b9 f4 00 0f 84 9c 01 00 00 <44> 85 73 10 74 ea
      44 8b 6b 14 41 f6 c5 01 75 d4 41 f6 c5 02 74 0f
RSP: 0018:ff71570009e07a80 EFLAGS: 00010207
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000200
RDX: ffffffffad8dc7c0 RSI: 0000000024924925 RDI: ff3e27850dea2000
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffffabfce739
R10: ff3e27810cc42400 R11: 0000000000000000 R12: ff3e2781825ef970
R13: 00000000ff3e2785 R14: 000000000000000c R15: 0000000000000001
FS:  00007f5195b51740(0000)
GS:ff3e278b12d40000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000010 CR3: 0000000626d24002 CR4: 0000000000361ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 ima_get_action+0x22/0x30
 process_measurement+0xb0/0x830
 ? page_add_file_rmap+0x15/0x170
 ? alloc_set_pte+0x269/0x4c0
 ? prep_new_page+0x81/0x140
 ? simple_xattr_get+0x75/0xa0
 ? selinux_file_open+0x9d/0xf0
 ima_file_check+0x64/0x90
 path_openat+0x571/0x1720
 do_filp_open+0x9b/0x110
 ? page_counter_try_charge+0x57/0xc0
 ? files_cgroup_alloc_fd+0x38/0x60
 ? __alloc_fd+0xd4/0x250
 ? do_sys_open+0x1bd/0x250
 do_sys_open+0x1bd/0x250
 do_syscall_64+0x5d/0x1d0
 entry_SYSCALL_64_after_hwframe+0x65/0xca

Commit c7423dbdbc ("ima: Handle -ESTALE returned by
ima_filter_rule_match()") introduced call to ima_lsm_copy_rule within a
RCU read-side critical section which contains kmalloc with GFP_KERNEL.
This implies a possible sleep and violates limitations of RCU read-side
critical sections on non-PREEMPT systems.

Sleeping within RCU read-side critical section might cause
synchronize_rcu() returning early and break RCU protection, allowing a
UAF to happen.

The root cause of this issue could be described as follows:
|	Thread A	|	Thread B	|
|			|ima_match_policy	|
|			|  rcu_read_lock	|
|ima_lsm_update_rule	|			|
|  synchronize_rcu	|			|
|			|    kmalloc(GFP_KERNEL)|
|			|      sleep		|
==> synchronize_rcu returns early
|  kfree(entry)		|			|
|			|    entry = entry->next|
==> UAF happens and entry now becomes NULL (or could be anything).
|			|    entry->action	|
==> Accessing entry might cause panic.

To fix this issue, we are converting all kmalloc that is called within
RCU read-side critical section to use GFP_ATOMIC.

Fixes: c7423dbdbc ("ima: Handle -ESTALE returned by ima_filter_rule_match()")
Cc: stable@vger.kernel.org
Signed-off-by: GUO Zihua <guozihua@huawei.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: fixed missing comment, long lines, !CONFIG_IMA_LSM_RULES case]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-06-13 14:26:50 -04:00
Casey Schaufler
223981db9b AppArmor: Add selfattr hooks
Add hooks for setselfattr and getselfattr. These hooks are not very
different from their setprocattr and getprocattr equivalents, and
much of the code is shared.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: John Johansen <john.johansen@canonical.com>
[PM: forward ported beyond v6.6 due merge window changes]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-11-12 22:54:42 -05:00
John Johansen
157a3537d6 apparmor: Fix regression in mount mediation
commit 2db154b3ea ("vfs: syscall: Add move_mount(2) to move mounts around")

introduced a new move_mount(2) system call and a corresponding new LSM
security_move_mount hook but did not implement this hook for any
existing LSM. This creates a regression for AppArmor mediation of
mount. This patch provides a base mapping of the move_mount syscall to
the existing mount mediation. In the future we may introduce
additional mediations around the new mount calls.

Fixes: 2db154b3ea ("vfs: syscall: Add move_mount(2) to move mounts around")
CC: stable@vger.kernel.org
Reported-by: Andreas Steinmetz <anstein99@googlemail.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2023-10-18 16:01:32 -07:00
Georgia Garcia
c4371d9063 apparmor: add io_uring mediation
For now, the io_uring mediation is limited to sqpoll and
override_creds.

Signed-off-by: Georgia Garcia <georgia.garcia@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2023-10-18 15:58:49 -07:00
John Johansen
fa9b63adab apparmor: add user namespace creation mediation
Unprivileged user namespace creation is often used as a first step
in privilege escalation attacks. Instead of disabling it at the
sysrq level, which blocks its legitimate use as for setting up a sandbox,
allow control on a per domain basis.

This allows an admin to quickly lock down a system while also still
allowing legitimate use.

Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2023-10-18 15:49:02 -07:00
John Johansen
2d9da9b188 apparmor: allow restricting unprivileged change_profile
unprivileged unconfined can use change_profile to alter the confinement
set by the mac admin.

Allow restricting unprivileged unconfined by still allowing change_profile
but stacking the change against unconfined. This allows unconfined to
still apply system policy but allows the task to enter the new confinement.

If unprivileged unconfined is required a sysctl is provided to switch
to the previous behavior.

Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2023-10-18 15:48:44 -07:00
John Johansen
98b824ff89 apparmor: refcount the pdb
With the move to permission tables the dfa is no longer a stand
alone entity when used, needing a minimum of a permission table.
However it still could be shared among different pdbs each using
a different permission table.

Instead of duping the permission table when sharing a pdb, add a
refcount to the pdb so it can be easily shared.

Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2023-10-18 15:30:47 -07:00
John Johansen
90c436a64a apparmor: pass cred through to audit info.
The cred is needed to properly audit some messages, and will be needed
in the future for uid conditional mediation. So pass it through to
where the apparmor_audit_data struct gets defined.

Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2023-10-18 15:30:38 -07:00
John Johansen
d20f5a1a6e apparmor: rename audit_data->label to audit_data->subj_label
rename audit_data's label field to subj_label to better reflect its
use. Also at the same time drop unneeded assignments to ->subj_label
as the later call to aa_check_perms will do the assignment if needed.

Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2023-10-18 15:30:34 -07:00
John Johansen
bd7bd201ca apparmor: combine common_audit_data and apparmor_audit_data
Everywhere where common_audit_data is used apparmor audit_data is also
used. We can simplify the code and drop the use of the aad macro
everywhere by combining the two structures.

Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2023-10-18 15:30:29 -07:00
John Johansen
79ddd4a7c5 apparmor: rename SK_CTX() to aa_sock and make it an inline fn
In preparation for LSM stacking rework the macro to an inline fn

Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2023-10-18 15:29:55 -07:00
Xiu Jianfeng
fee5304a9c apparmor: remove unused functions in policy_ns.c/.h
These functions are not used now, remove them.

Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2023-10-15 21:44:31 -07:00
GONG, Ruiqi
efea5b0dcc apparmor: remove unused PROF_* macros
The last usage of PROF_{ADD,REPLACE} were removed by commit 18e99f191a
("apparmor: provide finer control over policy management"). So remove
these two unused macros.

Signed-off-by: GONG, Ruiqi <gongruiqi1@huawei.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2023-08-08 13:24:48 -07:00
Xiu Jianfeng
980a580868 apparmor: cleanup unused functions in file.h
After changes in commit 33bf60cabc ("LSM: Infrastructure management of
the file security"), aa_alloc_file_ctx() and aa_free_file_ctx() are no
longer used, so remove them, and also remove aa_get_file_label() because
it seems that it's never been used before.

Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2023-08-08 13:16:13 -07:00
Xiu Jianfeng
9a0dbdbff0 apparmor: cleanup unused declarations in policy.h
The implementions of these declarations do not exist, remove them all.

Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2023-08-08 13:15:39 -07:00