linux-stable.git/security/apparmor, branch v7.0.4

apparmor: use target task's context in apparmor_getprocattr()

2026-05-07T04:14:11+00:00

commit 4afc61702bdcc3b9b519749ef966cf762a6e7051 upstream.

apparmor_getprocattr() incorrectly calls task_ctx(current) instead of
task_ctx(task) when retrieving prev and exec attributes, returning the
caller's labels rather than the target's.

Fix by passing task to task_ctx().

The issue can be reproduced when a process with an onexec transition
(e.g., configured by a container runtime) is inspected via
/proc//attr/apparmor/exec. The reader's own value is returned
instead of the target's.

Reported-by: Qualys Security Advisory 
Fixes: 3b529a7600d8 ("apparmor: move task domain change info to task security")
Cc: stable@vger.kernel.org
Co-developed-by: Cengiz Can 
Signed-off-by: Cengiz Can 
Co-developed-by: John Johansen 
Signed-off-by: John Johansen 
Signed-off-by: Greg Kroah-Hartman

apparmor: Fix string overrun due to missing termination

2026-05-07T04:13:59+00:00

commit 828bf7929bedcb79b560b5b4e44f22abee07d31b upstream.

When booting Ubuntu 26.04 with Linux 7.0-rc4 on an ARM64 Qualcomm
Snapdragon X1 we see a string buffer overrun:

BUG: KASAN: slab-out-of-bounds in aa_dfa_match (security/apparmor/match.c:535)
Read of size 1 at addr ffff0008901cc000 by task snap-update-ns/2120

CPU: 5 UID: 60578 PID: 2120 Comm: snap-update-ns Not tainted 7.0.0-rc4+ #22 PREEMPTLAZY
Hardware name: LENOVO 83ED/LNVNB161216, BIOS NHCN60WW 09/11/2025
Call trace:
show_stack (arch/arm64/kernel/stacktrace.c:501) (C)
dump_stack_lvl (lib/dump_stack.c:122)
print_report (mm/kasan/report.c:379 mm/kasan/report.c:482)
kasan_report (mm/kasan/report.c:597)
__asan_report_load1_noabort (mm/kasan/report_generic.c:378)
aa_dfa_match (security/apparmor/match.c:535)
match_mnt_path_str (security/apparmor/mount.c:244 security/apparmor/mount.c:336)
match_mnt (security/apparmor/mount.c:371)
aa_bind_mount (security/apparmor/mount.c:447 (discriminator 4))
apparmor_sb_mount (security/apparmor/lsm.c:719 (discriminator 1))
security_sb_mount (security/security.c:1062 (discriminator 31))
path_mount (fs/namespace.c:4101)
__arm64_sys_mount (fs/namespace.c:4172 fs/namespace.c:4361 fs/namespace.c:4338 fs/namespace.c:4338)
invoke_syscall.constprop.0 (arch/arm64/kernel/syscall.c:35 arch/arm64/kernel/syscall.c:49)
el0_svc_common.constprop.0 (./include/linux/thread_info.h:142 (discriminator 2) arch/arm64/kernel/syscall.c:140 (discriminator 2))
do_el0_svc (arch/arm64/kernel/syscall.c:152)
el0_svc (arch/arm64/kernel/entry-common.c:80 arch/arm64/kernel/entry-common.c:725)
el0t_64_sync_handler (arch/arm64/kernel/entry-common.c:744)
el0t_64_sync (arch/arm64/kernel/entry.S:596)

Allocated by task 2120:
kasan_save_stack (mm/kasan/common.c:58)
kasan_save_track (./arch/arm64/include/asm/current.h:19 mm/kasan/common.c:70 mm/kasan/common.c:79)
kasan_save_alloc_info (mm/kasan/generic.c:571)
__kasan_kmalloc (mm/kasan/common.c:419)
__kmalloc_noprof (./include/linux/kasan.h:263 mm/slub.c:5260 mm/slub.c:5272)
aa_get_buffer (security/apparmor/lsm.c:2201)
aa_bind_mount (security/apparmor/mount.c:442)
apparmor_sb_mount (security/apparmor/lsm.c:719 (discriminator 1))
security_sb_mount (security/security.c:1062 (discriminator 31))
path_mount (fs/namespace.c:4101)
__arm64_sys_mount (fs/namespace.c:4172 fs/namespace.c:4361 fs/namespace.c:4338 fs/namespace.c:4338)
invoke_syscall.constprop.0 (arch/arm64/kernel/syscall.c:35 arch/arm64/kernel/syscall.c:49)
el0_svc_common.constprop.0 (./include/linux/thread_info.h:142 (discriminator 2) arch/arm64/kernel/syscall.c:140 (discriminator 2))
do_el0_svc (arch/arm64/kernel/syscall.c:152)
el0_svc (arch/arm64/kernel/entry-common.c:80 arch/arm64/kernel/entry-common.c:725)
el0t_64_sync_handler (arch/arm64/kernel/entry-common.c:744)
el0t_64_sync (arch/arm64/kernel/entry.S:596)

The buggy address belongs to the object at ffff0008901ca000
which belongs to the cache kmalloc-rnd-06-8k of size 8192
The buggy address is located 0 bytes to the right of
allocated 8192-byte region [ffff0008901ca000, ffff0008901cc000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x9101c8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:-1 pincount:0
flags: 0x8000000000000040(head|zone=2)
page_type: f5(slab)
raw: 8000000000000040 ffff000800016c40 fffffdffe2d14e10 ffff000800015c70
raw: 0000000000000000 0000000800010001 00000000f5000000 0000000000000000
head: 8000000000000040 ffff000800016c40 fffffdffe2d14e10 ffff000800015c70
head: 0000000000000000 0000000800010001 00000000f5000000 0000000000000000
head: 8000000000000003 fffffdffe2407201 fffffdffffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff0008901cbf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff0008901cbf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff0008901cc000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff0008901cc080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff0008901cc100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc

This was introduced by previous incorrect conversion from strcpy(). Fix it
by adding the missing terminator.

Cc: stable@vger.kernel.org
Reviewed-by: Georgia Garcia 
Signed-off-by: Daniel J Blueman 
Fixes: 93d4dbdc8da0 ("apparmor: Replace deprecated strcpy in d_namespace_path")
Signed-off-by: John Johansen 
Signed-off-by: Greg Kroah-Hartman

apparmor: fix race between freeing data and fs accessing it

2026-03-09T23:05:44+00:00

AppArmor was putting the reference to i_private data on its end after
removing the original entry from the file system. However the inode
can aand does live beyond that point and it is possible that some of
the fs call back functions will be invoked after the reference has
been put, which results in a race between freeing the data and
accessing it through the fs.

While the rawdata/loaddata is the most likely candidate to fail the
race, as it has the fewest references. If properly crafted it might be
possible to trigger a race for the other types stored in i_private.

Fix this by moving the put of i_private referenced data to the correct
place which is during inode eviction.

Fixes: c961ee5f21b20 ("apparmor: convert from securityfs to apparmorfs for policy ns files")
Reported-by: Qualys Security Advisory 
Reviewed-by: Georgia Garcia 
Reviewed-by: Maxime Bélair 
Reviewed-by: Cengiz Can 
Signed-off-by: John Johansen

apparmor: fix race on rawdata dereference

2026-03-09T23:05:44+00:00

There is a race condition that leads to a use-after-free situation:
because the rawdata inodes are not refcounted, an attacker can start
open()ing one of the rawdata files, and at the same time remove the
last reference to this rawdata (by removing the corresponding profile,
for example), which frees its struct aa_loaddata; as a result, when
seq_rawdata_open() is reached, i_private is a dangling pointer and
freed memory is accessed.

The rawdata inodes weren't refcounted to avoid a circular refcount and
were supposed to be held by the profile rawdata reference.  However
during profile removal there is a window where the vfs and profile
destruction race, resulting in the use after free.

Fix this by moving to a double refcount scheme. Where the profile
refcount on rawdata is used to break the circular dependency. Allowing
for freeing of the rawdata once all inode references to the rawdata
are put.

Fixes: 5d5182cae401 ("apparmor: move to per loaddata files, instead of replicating in profiles")
Reported-by: Qualys Security Advisory 
Reviewed-by: Georgia Garcia 
Reviewed-by: Maxime Bélair 
Reviewed-by: Cengiz Can 
Tested-by: Salvatore Bonaccorso 
Signed-off-by: John Johansen

apparmor: fix differential encoding verification

2026-03-09T23:05:43+00:00

Differential encoding allows loops to be created if it is abused. To
prevent this the unpack should verify that a diff-encode chain
terminates.

Unfortunately the differential encode verification had two bugs.

1. it conflated states that had gone through check and already been
   marked, with states that were currently being checked and marked.
   This means that loops in the current chain being verified are treated
   as a chain that has already been verified.

2. the order bailout on already checked states compared current chain
   check iterators j,k instead of using the outer loop iterator i.
   Meaning a step backwards in states in the current chain verification
   was being mistaken for moving to an already verified state.

Move to a double mark scheme where already verified states get a
different mark, than the current chain being kept. This enables us
to also drop the backwards verification check that was the cause of
the second error as any already verified state is already marked.

Fixes: 031dcc8f4e84 ("apparmor: dfa add support for state differential encoding")
Reported-by: Qualys Security Advisory 
Tested-by: Salvatore Bonaccorso 
Reviewed-by: Georgia Garcia 
Reviewed-by: Cengiz Can 
Signed-off-by: John Johansen

apparmor: fix unprivileged local user can do privileged policy management

2026-03-09T23:05:43+00:00

An unprivileged local user can load, replace, and remove profiles by
opening the apparmorfs interfaces, via a confused deputy attack, by
passing the opened fd to a privileged process, and getting the
privileged process to write to the interface.

This does require a privileged target that can be manipulated to do
the write for the unprivileged process, but once such access is
achieved full policy management is possible and all the possible
implications that implies: removing confinement, DoS of system or
target applications by denying all execution, by-passing the
unprivileged user namespace restriction, to exploiting kernel bugs for
a local privilege escalation.

The policy management interface can not have its permissions simply
changed from 0666 to 0600 because non-root processes need to be able
to load policy to different policy namespaces.

Instead ensure the task writing the interface has privileges that
are a subset of the task that opened the interface. This is already
done via policy for confined processes, but unconfined can delegate
access to the opened fd, by-passing the usual policy check.

Fixes: b7fd2c0340eac ("apparmor: add per policy ns .load, .replace, .remove interface files")
Reported-by: Qualys Security Advisory 
Tested-by: Salvatore Bonaccorso 
Reviewed-by: Georgia Garcia 
Reviewed-by: Cengiz Can 
Signed-off-by: John Johansen

apparmor: Fix double free of ns_name in aa_replace_profiles()

2026-03-09T23:05:43+00:00

if ns_name is NULL after
1071         error = aa_unpack(udata, &lh, &ns_name);

and if ent->ns_name contains an ns_name in
1089                 } else if (ent->ns_name) {

then ns_name is assigned the ent->ns_name
1095                         ns_name = ent->ns_name;

however ent->ns_name is freed at
1262                 aa_load_ent_free(ent);

and then again when freeing ns_name at
1270         kfree(ns_name);

Fix this by NULLing out ent->ns_name after it is transferred to ns_name

Fixes: 145a0ef21c8e9 ("apparmor: fix blob compression when ns is forced on a policy load
")
Reported-by: Qualys Security Advisory 
Tested-by: Salvatore Bonaccorso 
Reviewed-by: Georgia Garcia 
Reviewed-by: Cengiz Can 
Signed-off-by: John Johansen

apparmor: fix missing bounds check on DEFAULT table in verify_dfa()

2026-03-09T23:05:43+00:00

The verify_dfa() function only checks DEFAULT_TABLE bounds when the state
is not differentially encoded.

When the verification loop traverses the differential encoding chain,
it reads k = DEFAULT_TABLE[j] and uses k as an array index without
validation. A malformed DFA with DEFAULT_TABLE[j] >= state_count,
therefore, causes both out-of-bounds reads and writes.

[   57.179855] ==================================================================
[   57.180549] BUG: KASAN: slab-out-of-bounds in verify_dfa+0x59a/0x660
[   57.180904] Read of size 4 at addr ffff888100eadec4 by task su/993

[   57.181554] CPU: 1 UID: 0 PID: 993 Comm: su Not tainted 6.19.0-rc7-next-20260127 #1 PREEMPT(lazy)
[   57.181558] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[   57.181563] Call Trace:
[   57.181572]  
[   57.181577]  dump_stack_lvl+0x5e/0x80
[   57.181596]  print_report+0xc8/0x270
[   57.181605]  ? verify_dfa+0x59a/0x660
[   57.181608]  kasan_report+0x118/0x150
[   57.181620]  ? verify_dfa+0x59a/0x660
[   57.181623]  verify_dfa+0x59a/0x660
[   57.181627]  aa_dfa_unpack+0x1610/0x1740
[   57.181629]  ? __kmalloc_cache_noprof+0x1d0/0x470
[   57.181640]  unpack_pdb+0x86d/0x46b0
[   57.181647]  ? srso_alias_return_thunk+0x5/0xfbef5
[   57.181653]  ? srso_alias_return_thunk+0x5/0xfbef5
[   57.181656]  ? aa_unpack_nameX+0x1a8/0x300
[   57.181659]  aa_unpack+0x20b0/0x4c30
[   57.181662]  ? srso_alias_return_thunk+0x5/0xfbef5
[   57.181664]  ? stack_depot_save_flags+0x33/0x700
[   57.181681]  ? kasan_save_track+0x4f/0x80
[   57.181683]  ? kasan_save_track+0x3e/0x80
[   57.181686]  ? __kasan_kmalloc+0x93/0xb0
[   57.181688]  ? __kvmalloc_node_noprof+0x44a/0x780
[   57.181693]  ? aa_simple_write_to_buffer+0x54/0x130
[   57.181697]  ? policy_update+0x154/0x330
[   57.181704]  aa_replace_profiles+0x15a/0x1dd0
[   57.181707]  ? srso_alias_return_thunk+0x5/0xfbef5
[   57.181710]  ? __kvmalloc_node_noprof+0x44a/0x780
[   57.181712]  ? aa_loaddata_alloc+0x77/0x140
[   57.181715]  ? srso_alias_return_thunk+0x5/0xfbef5
[   57.181717]  ? _copy_from_user+0x2a/0x70
[   57.181730]  policy_update+0x17a/0x330
[   57.181733]  profile_replace+0x153/0x1a0
[   57.181735]  ? rw_verify_area+0x93/0x2d0
[   57.181740]  vfs_write+0x235/0xab0
[   57.181745]  ksys_write+0xb0/0x170
[   57.181748]  do_syscall_64+0x8e/0x660
[   57.181762]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[   57.181765] RIP: 0033:0x7f6192792eb2

Remove the MATCH_FLAG_DIFF_ENCODE condition to validate all DEFAULT_TABLE
entries unconditionally.

Fixes: 031dcc8f4e84 ("apparmor: dfa add support for state differential encoding")
Reported-by: Qualys Security Advisory 
Tested-by: Salvatore Bonaccorso 
Reviewed-by: Georgia Garcia 
Reviewed-by: Cengiz Can 
Signed-off-by: Massimiliano Pellizzer 
Signed-off-by: John Johansen

apparmor: fix side-effect bug in match_char() macro usage

2026-03-09T23:05:43+00:00

The match_char() macro evaluates its character parameter multiple
times when traversing differential encoding chains. When invoked
with *str++, the string pointer advances on each iteration of the
inner do-while loop, causing the DFA to check different characters
at each iteration and therefore skip input characters.
This results in out-of-bounds reads when the pointer advances past
the input buffer boundary.

[   94.984676] ==================================================================
[   94.985301] BUG: KASAN: slab-out-of-bounds in aa_dfa_match+0x5ae/0x760
[   94.985655] Read of size 1 at addr ffff888100342000 by task file/976

[   94.986319] CPU: 7 UID: 1000 PID: 976 Comm: file Not tainted 6.19.0-rc7-next-20260127 #1 PREEMPT(lazy)
[   94.986322] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[   94.986329] Call Trace:
[   94.986341]  
[   94.986347]  dump_stack_lvl+0x5e/0x80
[   94.986374]  print_report+0xc8/0x270
[   94.986384]  ? aa_dfa_match+0x5ae/0x760
[   94.986388]  kasan_report+0x118/0x150
[   94.986401]  ? aa_dfa_match+0x5ae/0x760
[   94.986405]  aa_dfa_match+0x5ae/0x760
[   94.986408]  __aa_path_perm+0x131/0x400
[   94.986418]  aa_path_perm+0x219/0x2f0
[   94.986424]  apparmor_file_open+0x345/0x570
[   94.986431]  security_file_open+0x5c/0x140
[   94.986442]  do_dentry_open+0x2f6/0x1120
[   94.986450]  vfs_open+0x38/0x2b0
[   94.986453]  ? may_open+0x1e2/0x2b0
[   94.986466]  path_openat+0x231b/0x2b30
[   94.986469]  ? __x64_sys_openat+0xf8/0x130
[   94.986477]  do_file_open+0x19d/0x360
[   94.986487]  do_sys_openat2+0x98/0x100
[   94.986491]  __x64_sys_openat+0xf8/0x130
[   94.986499]  do_syscall_64+0x8e/0x660
[   94.986515]  ? count_memcg_events+0x15f/0x3c0
[   94.986526]  ? srso_alias_return_thunk+0x5/0xfbef5
[   94.986540]  ? handle_mm_fault+0x1639/0x1ef0
[   94.986551]  ? vma_start_read+0xf0/0x320
[   94.986558]  ? srso_alias_return_thunk+0x5/0xfbef5
[   94.986561]  ? srso_alias_return_thunk+0x5/0xfbef5
[   94.986563]  ? fpregs_assert_state_consistent+0x50/0xe0
[   94.986572]  ? srso_alias_return_thunk+0x5/0xfbef5
[   94.986574]  ? arch_exit_to_user_mode_prepare+0x9/0xb0
[   94.986587]  ? srso_alias_return_thunk+0x5/0xfbef5
[   94.986588]  ? irqentry_exit+0x3c/0x590
[   94.986595]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[   94.986597] RIP: 0033:0x7fda4a79c3ea

Fix by extracting the character value before invoking match_char,
ensuring single evaluation per outer loop.

Fixes: 074c1cd798cb ("apparmor: dfa move character match into a macro")
Reported-by: Qualys Security Advisory 
Tested-by: Salvatore Bonaccorso 
Reviewed-by: Georgia Garcia 
Reviewed-by: Cengiz Can 
Signed-off-by: Massimiliano Pellizzer 
Signed-off-by: John Johansen

apparmor: fix: limit the number of levels of policy namespaces

2026-03-09T23:05:43+00:00

Currently the number of policy namespaces is not bounded relying on
the user namespace limit. However policy namespaces aren't strictly
tied to user namespaces and it is possible to create them and nest
them arbitrarily deep which can be used to exhaust system resource.

Hard cap policy namespaces to the same depth as user namespaces.

Fixes: c88d4c7b049e8 ("AppArmor: core policy routines")
Reported-by: Qualys Security Advisory 
Reviewed-by: Ryan Lee 
Reviewed-by: Cengiz Can 
Signed-off-by: John Johansen