kernel/linux.git/security/apparmor/file.c, branch v7.2-rc1

apparmor: fix uninitialised pointer passed to audit_log_untrustedstring()

2026-06-14T03:20:13+00:00

Commit 4a134723f9f1 ("apparmor: move check for aa_null file to cover all cases") intrdouced a small bug, where path_name() may pass a potentially uninitialized *name to aa_audit_file() if the path->dentry had been replaced with aa_null.dentry earlier on. This can lead to page fault like one observed on 7.0.2 openSUSE Tumbleweed kernel: [51692.242756] [ T24690] BUG: unable to handle page fault for address: 0000000f00000003 [51692.242762] [ T24690] #PF: supervisor read access in kernel mode [51692.242763] [ T24690] #PF: error_code(0x0000) - not-present page [51692.242765] [ T24690] PGD 0 P4D 0 [51692.242768] [ T24690] Oops: Oops: 0000 [#1] SMP NOPTI [51692.242772] [ T24690] CPU: 3 UID: 1020 PID: 24690 Comm: snap-confine Tainted: G O 7.0.2-1-default #1 PREEMPT(full) openSUSE Tumbleweed ab90b4c9940707f9cafa19bdad80b2cec52dbe51 [51692.242775] [ T24690] Tainted: [O]=OOT_MODULE [51692.242777] [ T24690] Hardware name: Framework Laptop 13 (AMD Ryzen 7040Series)/FRANMDCP05, BIOS 03.18 01/08/2026 [51692.242778] [ T24690] RIP: 0010:strlen+0x4/0x30 [51692.242783] [ T24690] Code: f7 75 ec 31 c0 e9 17 9f 00 ff 48 89 f8 e9 0f 9f 00 ff 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa <80> 3f 00 74 18 48 89 f8 0f 1f 40 00 48 83 c0 01 80 38 00 75 f7 48 [51692.242785] [ T24690] RSP: 0018:ffffd015eb1e3608 EFLAGS: 00010282 [51692.242787] [ T24690] RAX: 0000000000000000 RBX: ffff89796198a360 RCX: 0000000000000000 [51692.242788] [ T24690] RDX: 00000000000000d1 RSI: 0000000f00000003 RDI: 0000000f00000003 [51692.242790] [ T24690] RBP: ffffffffb7ede090 R08: 00000000000005f5 R09: 0000000000000000 [51692.242791] [ T24690] R10: 0000000000000000 R11: 0000000000000000 R12: ffffd015eb1e3700 [51692.242792] [ T24690] R13: ffff8977a22bc380 R14: ffffffffb7ec5190 R15: ffff8977a0c8aa80 [51692.242794] [ T24690] FS: 0000000000000000(0000) GS:ffff897f640d8000(0000) knlGS:0000000000000000 [51692.242796] [ T24690] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [51692.242797] [ T24690] CR2: 0000000f00000003 CR3: 00000006ad15f000 CR4: 0000000000f50ef0 [51692.242799] [ T24690] PKRU: 55555554 [51692.242800] [ T24690] Call Trace: [51692.242802] [ T24690] [51692.242804] [ T24690] audit_log_untrustedstring+0x1d/0x40 [51692.242811] [ T24690] common_lsm_audit+0x71/0x1d0 [51692.242816] [ T24690] aa_audit+0x5a/0x170 [51692.242819] [ T24690] aa_audit_file+0x18a/0x1b0 [51692.242825] [ T24690] path_name+0xd2/0x100 [51692.242829] [ T24690] profile_path_perm.part.0+0x58/0xb0 [51692.242832] [ T24690] aa_path_perm+0xef/0x150 [51692.242837] [ T24690] apparmor_file_open+0x153/0x2e0 [51692.242840] [ T24690] security_file_open+0x46/0xd0 [51692.242844] [ T24690] do_dentry_open+0xe9/0x4d0 [51692.242848] [ T24690] vfs_open+0x30/0x100 While here, initialise variables which are passed down to path_name(). Fixes: 4a134723f9f1 ("apparmor: move check for aa_null file to cover all cases") Signed-off-by: Maciek Borzecki Signed-off-by: John Johansen

apparmor: don't audit files pointing to aa_null.dentry

2026-06-14T03:20:05+00:00

In commit 4a134723f9f1 ("apparmor: move check for aa_null file to cover all cases") there was a change to not audit files pointing to aa_null.dentry because they provide no value, but setting the error variable instead of returning -EACCES was still causing them to be audited. Fixes: 4a134723f9f1 ("apparmor: move check for aa_null file to cover all cases") Acked-by: David Disseldorp Signed-off-by: Georgia Garcia Signed-off-by: John Johansen

apparmor: fix fast path cache check for unix sockets

2026-01-29T09:27:54+00:00

The fast path cache check is incorrect forcing more slow path revalidations than necessary, because the unix logic check is inverted. Reviewed-by: Georgia Garcia Signed-off-by: John Johansen

apparmor: move check for aa_null file to cover all cases

2026-01-29T09:27:54+00:00

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

apparmor: add support loading per permission tagging

2026-01-29T09:27:47+00:00

Add support for the per permission tag index for a given permission set. This will be used by both meta-data tagging, to allow annotating accept states with context and debug information. As well as by rule tainting and triggers to specify the taint or trigger to be applied. Since these are low frequency ancillary data items they are stored in a tighter packed format to that allows for sharing and reuse of the strings between permissions and accept states. Reducing the amount of kernel memory use at the cost of having to go through a couple if index based indirections. The tags are just strings that has no meaning with out context. When used as meta-data for auditing and debugging its entirely information for userspace, but triggers, and tainting can be used to affect the domain. However they all exist in the same packed data set and can be shared between different uses. Signed-off-by: John Johansen

apparmor: fix NULL pointer dereference in __unix_needs_revalidation

2026-01-18T15:06:30+00:00

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

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