kernel/linux.git/security/apparmor/policy.c, branch v6.18.21

apparmor: fix race on rawdata dereference

2026-03-13T16:23:29+00:00

commit a0b7091c4de45a7325c8780e6934a894f92ac86b upstream. 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 Signed-off-by: Greg Kroah-Hartman

apparmor: fix unprivileged local user can do privileged policy management

2026-03-13T16:23:29+00:00

commit 6601e13e82841879406bf9f369032656f441a425 upstream. 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 Signed-off-by: Greg Kroah-Hartman

apparmor: Fix double free of ns_name in aa_replace_profiles()

2026-03-13T16:23:29+00:00

commit 5df0c44e8f5f619d3beb871207aded7c78414502 upstream. 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 Signed-off-by: Greg Kroah-Hartman

apparmor: replace recursive profile removal with iterative approach

2026-03-13T16:23:29+00:00

commit ab09264660f9de5d05d1ef4e225aa447c63a8747 upstream. The profile removal code uses recursion when removing nested profiles, which can lead to kernel stack exhaustion and system crashes. Reproducer: $ pf='a'; for ((i=0; i<1024; i++)); do echo -e "profile $pf { \n }" | apparmor_parser -K -a; pf="$pf//x"; done $ echo -n a > /sys/kernel/security/apparmor/.remove Replace the recursive __aa_profile_list_release() approach with an iterative approach in __remove_profile(). The function repeatedly finds and removes leaf profiles until the entire subtree is removed, maintaining the same removal semantic without recursion. Fixes: c88d4c7b049e ("AppArmor: core policy routines") 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 Signed-off-by: Greg Kroah-Hartman

apparmor: fix: oops when trying to free null ruleset

2025-08-04T08:14:56+00:00

profile allocation is wrongly setting the number of entries on the rules vector before any ruleset is assigned. If profile allocation fails between ruleset allocation and assigning the first ruleset, free_ruleset() will be called with a null pointer resulting in an oops. [ 107.350226] kernel BUG at mm/slub.c:545! [ 107.350912] Oops: invalid opcode: 0000 [#1] PREEMPT SMP NOPTI [ 107.351447] CPU: 1 UID: 0 PID: 27 Comm: ksoftirqd/1 Not tainted 6.14.6-hwe-rlee287-dev+ #5 [ 107.353279] Hardware name:[ 107.350218] -QE-----------[ cutMU here ]--------- Ub--- [ 107.3502untu26] kernel BUG a 24t mm/slub.c:545.!04 P [ 107.350912]C ( Oops: invalid oi4pcode: 0000 [#1]40 PREEMPT SMP NOPFXTI + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 107.356054] RIP: 0010:__slab_free+0x152/0x340 [ 107.356444] Code: 00 4c 89 ff e8 0f ac df 00 48 8b 14 24 48 8b 4c 24 20 48 89 44 24 08 48 8b 03 48 c1 e8 09 83 e0 01 88 44 24 13 e9 71 ff ff ff <0f> 0b 41 f7 44 24 08 87 04 00 00 75 b2 eb a8 41 f7 44 24 08 87 04 [ 107.357856] RSP: 0018:ffffad4a800fbbb0 EFLAGS: 00010246 [ 107.358937] RAX: ffff97ebc2a88e70 RBX: ffffd759400aa200 RCX: 0000000000800074 [ 107.359976] RDX: ffff97ebc2a88e60 RSI: ffffd759400aa200 RDI: ffffad4a800fbc20 [ 107.360600] RBP: ffffad4a800fbc50 R08: 0000000000000001 R09: ffffffff86f02cf2 [ 107.361254] R10: 0000000000000000 R11: 0000000000000000 R12: ffff97ecc0049400 [ 107.361934] R13: ffff97ebc2a88e60 R14: ffff97ecc0049400 R15: 0000000000000000 [ 107.362597] FS: 0000000000000000(0000) GS:ffff97ecfb200000(0000) knlGS:0000000000000000 [ 107.363332] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 107.363784] CR2: 000061c9545ac000 CR3: 0000000047aa6000 CR4: 0000000000750ef0 [ 107.364331] PKRU: 55555554 [ 107.364545] Call Trace: [ 107.364761] [ 107.364931] ? local_clock+0x15/0x30 [ 107.365219] ? srso_alias_return_thunk+0x5/0xfbef5 [ 107.365593] ? kfree_sensitive+0x32/0x70 [ 107.365900] kfree+0x29d/0x3a0 [ 107.366144] ? srso_alias_return_thunk+0x5/0xfbef5 [ 107.366510] ? local_clock_noinstr+0xe/0xd0 [ 107.366841] ? srso_alias_return_thunk+0x5/0xfbef5 [ 107.367209] kfree_sensitive+0x32/0x70 [ 107.367502] aa_free_profile.part.0+0xa2/0x400 [ 107.367850] ? rcu_do_batch+0x1e6/0x5e0 [ 107.368148] aa_free_profile+0x23/0x60 [ 107.368438] label_free_switch+0x4c/0x80 [ 107.368751] label_free_rcu+0x1c/0x50 [ 107.369038] rcu_do_batch+0x1e8/0x5e0 [ 107.369324] ? rcu_do_batch+0x157/0x5e0 [ 107.369626] rcu_core+0x1b0/0x2f0 [ 107.369888] rcu_core_si+0xe/0x20 [ 107.370156] handle_softirqs+0x9b/0x3d0 [ 107.370460] ? smpboot_thread_fn+0x26/0x210 [ 107.370790] run_ksoftirqd+0x3a/0x70 [ 107.371070] smpboot_thread_fn+0xf9/0x210 [ 107.371383] ? __pfx_smpboot_thread_fn+0x10/0x10 [ 107.371746] kthread+0x10d/0x280 [ 107.372010] ? __pfx_kthread+0x10/0x10 [ 107.372310] ret_from_fork+0x44/0x70 [ 107.372655] ? __pfx_kthread+0x10/0x10 [ 107.372974] ret_from_fork_asm+0x1a/0x30 [ 107.373316] [ 107.373505] Modules linked in: af_packet_diag mptcp_diag tcp_diag udp_diag raw_diag inet_diag snd_seq_dummy snd_hrtimer snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq snd_seq_device snd_timer snd soundcore qrtr binfmt_misc intel_rapl_msr intel_rapl_common kvm_amd ccp kvm irqbypass polyval_clmulni polyval_generic ghash_clmulni_intel sha256_ssse3 sha1_ssse3 aesni_intel crypto_simd cryptd i2c_piix4 i2c_smbus input_leds joydev sch_fq_codel msr parport_pc ppdev lp parport efi_pstore nfnetlink vsock_loopback vmw_vsock_virtio_transport_common vmw_vsock_vmci_transport vsock vmw_vmci dmi_sysfs qemu_fw_cfg ip_tables x_tables autofs4 hid_generic usbhid hid psmouse serio_raw floppy bochs pata_acpi [ 107.379086] ---[ end trace 0000000000000000 ]--- Don't set the count until a ruleset is actually allocated and guard against free_ruleset() being called with a null pointer. Reported-by: Ryan Lee Fixes: 217af7e2f4de ("apparmor: refactor profile rules and attachments") Signed-off-by: John Johansen

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: make __begin_current_label_crit_section() indicate whether put is needed

2025-07-16T05:39:43+00:00

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 Signed-off-by: John Johansen

apparmor: fix typos and spelling errors

2025-02-10T19:17:49+00:00

Fix typos and spelling errors in apparmor module comments that were identified using the codespell tool. No functional changes - documentation only. Signed-off-by: Tanya Agarwal Reviewed-by: Mimi Zohar Ryan Lee Signed-off-by: John Johansen

apparmor: add support for profiles to define the kill signal

2025-01-18T14:47:12+00:00

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

apparmor: carry mediation check on label

2025-01-18T14:47:12+00:00

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