kernel/linux.git/security/apparmor/file.c, branch v6.19.11

apparmor: move check for aa_null file to cover all cases

2026-02-26T23:01:34+00:00

[ Upstream commit 4a134723f9f1ad2f3621566259db673350d19cb1 ] files with a dentry pointing aa_null.dentry where already rejected as part of file_inheritance. Unfortunately the check in common_file_perm() is insufficient to cover all cases causing unnecessary audit messages without the original files context. Eg. [ 442.886474] audit: type=1400 audit(1704822661.616:329): apparmor="DENIED" operation="file_inherit" class="file" namespace="root//lxd-juju-98527a-0_" profile="snap.lxd.activate" name="/apparmor/.null" pid=9525 comm="snap-exec" Further examples of this are in the logs of https://bugs.launchpad.net/ubuntu/+source/apparmor/+bug/2120439 https://bugs.launchpad.net/ubuntu/+source/snapd/+bug/1952084 https://bugs.launchpad.net/snapd/+bug/2049099 These messages have no value and should not be sent to the logs. AppArmor was already filtering the out in some cases but the original patch did not catch all cases. Fix this by push the existing check down into two functions that should cover all cases. Link: https://bugs.launchpad.net/ubuntu/+source/apparmor/+bug/2122743 Fixes: 192ca6b55a86 ("apparmor: revalidate files during exec") Reviewed-by: Georgia Garcia Signed-off-by: John Johansen Signed-off-by: Sasha Levin

apparmor: fix NULL pointer dereference in __unix_needs_revalidation

2026-02-26T23:01:34+00:00

[ Upstream commit e2938ad00b21340c0362562dfedd7cfec0554d67 ] When receiving file descriptors via SCM_RIGHTS, both the socket pointer and the socket's sk pointer can be NULL during socket setup or teardown, causing NULL pointer dereferences in __unix_needs_revalidation(). This is a regression in AppArmor 5.0.0 (kernel 6.17+) where the new __unix_needs_revalidation() function was added without proper NULL checks. The crash manifests as: BUG: kernel NULL pointer dereference, address: 0x0000000000000018 RIP: aa_file_perm+0xb7/0x3b0 (or +0xbe/0x3b0, +0xc0/0x3e0) Call Trace: apparmor_file_receive+0x42/0x80 security_file_receive+0x2e/0x50 receive_fd+0x1d/0xf0 scm_detach_fds+0xad/0x1c0 The function dereferences sock->sk->sk_family without checking if either sock or sock->sk is NULL first. Add NULL checks for both sock and sock->sk before accessing sk_family. Fixes: 88fec3526e841 ("apparmor: make sure unix socket labeling is correctly updated.") Reported-by: Jamin Mc Closes: https://bugzilla.proxmox.com/show_bug.cgi?id=7083 Closes: https://gitlab.com/apparmor/apparmor/-/issues/568 Signed-off-by: Fabian Grünbichler Signed-off-by: System Administrator Signed-off-by: John Johansen Signed-off-by: Sasha Levin

Merge tag 'apparmor-pr-2025-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor

2025-08-04T15:17:28+00:00

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 ...

apparmor: transition from a list of rules to a vector of rules

2025-07-20T09:31:06+00:00

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

apparmor: shift ouid when mediating hard links in userns

2025-07-20T09:19:27+00:00

When using AppArmor profiles inside an unprivileged container, the link operation observes an unshifted ouid. (tested with LXD and Incus) For example, root inside container and uid 1000000 outside, with `owner /root/link l,` profile entry for ln: /root$ touch chain && ln chain link ==> dmesg apparmor="DENIED" operation="link" class="file" namespace="root//lxd-feet_" profile="linkit" name="/root/link" pid=1655 comm="ln" requested_mask="l" denied_mask="l" fsuid=1000000 ouid=0 [<== should be 1000000] target="/root/chain" Fix by mapping inode uid of old_dentry in aa_path_link() rather than using it directly, similarly to how it's mapped in __file_path_perm() later in the file. Signed-off-by: Gabriel Totev Signed-off-by: John Johansen

apparmor: make sure unix socket labeling is correctly updated.

2025-07-20T09:19:27+00:00

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: c05e705812d1 ("apparmor: add fine grained af_unix mediation") Signed-off-by: John Johansen

apparmor: file never has NULL f_path.mnt

2025-06-17T22:04:36+00:00

Reviewed-by: Christian Brauner Signed-off-by: Al Viro

apparmor: Remove unused variable 'sock' in __file_sock_perm()

2025-02-10T19:18:45+00:00

When CONFIG_SECURITY_APPARMOR_DEBUG_ASSERTS is disabled, there is a warning that sock is unused: security/apparmor/file.c: In function '__file_sock_perm': security/apparmor/file.c:544:24: warning: unused variable 'sock' [-Wunused-variable] 544 | struct socket *sock = (struct socket *) file->private_data; | ^~~~ sock was moved into aa_sock_file_perm(), where the same check is present, so remove sock and the assertion from __file_sock_perm() to fix the warning. Fixes: c05e705812d1 ("apparmor: add fine grained af_unix mediation") Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202501190757.myuLxLyL-lkp@intel.com/ Signed-off-by: Nathan Chancellor Signed-off-by: John Johansen

apparmor: Modify mismatched function name

2025-02-10T19:16:45+00:00

No functional modification involved. security/apparmor/file.c:184: warning: expecting prototype for aa_lookup_fperms(). Prototype was for aa_lookup_condperms() instead. Reported-by: Abaci Robot Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=13605 Signed-off-by: Jiapeng Chong Signed-off-by: John Johansen

apparmor: gate make fine grained unix mediation behind v9 abi

2025-01-18T14:47:13+00:00

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