kernel.git/security/apparmor/apparmorfs.c, branch linux-6.19.y

apparmor: fix race between freeing data and fs accessing it

2026-03-13T16:26:04Z

commit 8e135b8aee5a06c52a4347a5a6d51223c6f36ba3 upstream. 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 Signed-off-by: Greg Kroah-Hartman

apparmor: fix race on rawdata dereference

2026-03-13T16:26:04Z

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

2026-03-13T16:26:04Z

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 invalid deref of rawdata when export_binary is unset

2026-02-26T23:01:34Z

[ Upstream commit df9ac55abd18628bd8cff687ea043660532a3654 ] If the export_binary parameter is disabled on runtime, profiles that were loaded before that will still have their rawdata stored in apparmorfs, with a symbolic link to the rawdata on the policy directory. When one of those profiles are replaced, the rawdata is set to NULL, but when trying to resolve the symbolic links to rawdata for that profile, it will try to dereference profile->rawdata->name when profile->rawdata is now NULL causing an oops. Fix it by checking if rawdata is set. [ 168.653080] BUG: kernel NULL pointer dereference, address: 0000000000000088 [ 168.657420] #PF: supervisor read access in kernel mode [ 168.660619] #PF: error_code(0x0000) - not-present page [ 168.663613] PGD 0 P4D 0 [ 168.665450] Oops: Oops: 0000 [#1] SMP NOPTI [ 168.667836] CPU: 1 UID: 0 PID: 1729 Comm: ls Not tainted 6.19.0-rc7+ #3 PREEMPT(voluntary) [ 168.672308] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 168.679327] RIP: 0010:rawdata_get_link_base.isra.0+0x23/0x330 [ 168.682768] Code: 90 90 90 90 90 90 90 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 ec 18 48 89 55 d0 48 85 ff 0f 84 e3 01 00 00 <48> 83 3c 25 88 00 00 00 00 0f 84 d4 01 00 00 49 89 f6 49 89 cc e8 [ 168.689818] RSP: 0018:ffffcdcb8200fb80 EFLAGS: 00010282 [ 168.690871] RAX: ffffffffaee74ec0 RBX: 0000000000000000 RCX: ffffffffb0120158 [ 168.692251] RDX: ffffcdcb8200fbe0 RSI: ffff88c187c9fa80 RDI: ffff88c186c98a80 [ 168.693593] RBP: ffffcdcb8200fbc0 R08: 0000000000000000 R09: 0000000000000000 [ 168.694941] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88c186c98a80 [ 168.696289] R13: 00007fff005aaa20 R14: 0000000000000080 R15: ffff88c188f4fce0 [ 168.697637] FS: 0000790e81c58280(0000) GS:ffff88c20a957000(0000) knlGS:0000000000000000 [ 168.699227] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 168.700349] CR2: 0000000000000088 CR3: 000000012fd3e000 CR4: 0000000000350ef0 [ 168.701696] Call Trace: [ 168.702325] [ 168.702995] rawdata_get_link_data+0x1c/0x30 [ 168.704145] vfs_readlink+0xd4/0x160 [ 168.705152] do_readlinkat+0x114/0x180 [ 168.706214] __x64_sys_readlink+0x1e/0x30 [ 168.708653] x64_sys_call+0x1d77/0x26b0 [ 168.709525] do_syscall_64+0x81/0x500 [ 168.710348] ? do_statx+0x72/0xb0 [ 168.711109] ? putname+0x3e/0x80 [ 168.711845] ? __x64_sys_statx+0xb7/0x100 [ 168.712711] ? x64_sys_call+0x10fc/0x26b0 [ 168.713577] ? do_syscall_64+0xbf/0x500 [ 168.714412] ? do_user_addr_fault+0x1d2/0x8d0 [ 168.715404] ? irqentry_exit+0xb2/0x740 [ 168.716359] ? exc_page_fault+0x90/0x1b0 [ 168.717307] entry_SYSCALL_64_after_hwframe+0x76/0x7e Fixes: 1180b4c757aab ("apparmor: fix dangling symlinks to policy rawdata after replacement") Signed-off-by: Georgia Garcia Signed-off-by: John Johansen Signed-off-by: Sasha Levin

Merge tag 'pull-persistency' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2025-12-05T22:36:21Z

Pull persistent dentry infrastructure and conversion from Al Viro: "Some filesystems use a kinda-sorta controlled dentry refcount leak to pin dentries of created objects in dcache (and undo it when removing those). A reference is grabbed and not released, but it's not actually _stored_ anywhere. That works, but it's hard to follow and verify; among other things, we have no way to tell _which_ of the increments is intended to be an unpaired one. Worse, on removal we need to decide whether the reference had already been dropped, which can be non-trivial if that removal is on umount and we need to figure out if this dentry is pinned due to e.g. unlink() not done. Usually that is handled by using kill_litter_super() as ->kill_sb(), but there are open-coded special cases of the same (consider e.g. /proc/self). Things get simpler if we introduce a new dentry flag (DCACHE_PERSISTENT) marking those "leaked" dentries. Having it set claims responsibility for +1 in refcount. The end result this series is aiming for: - get these unbalanced dget() and dput() replaced with new primitives that would, in addition to adjusting refcount, set and clear persistency flag. - instead of having kill_litter_super() mess with removing the remaining "leaked" references (e.g. for all tmpfs files that hadn't been removed prior to umount), have the regular shrink_dcache_for_umount() strip DCACHE_PERSISTENT of all dentries, dropping the corresponding reference if it had been set. After that kill_litter_super() becomes an equivalent of kill_anon_super(). Doing that in a single step is not feasible - it would affect too many places in too many filesystems. It has to be split into a series. This work has really started early in 2024; quite a few preliminary pieces have already gone into mainline. This chunk is finally getting to the meat of that stuff - infrastructure and most of the conversions to it. Some pieces are still sitting in the local branches, but the bulk of that stuff is here" * tag 'pull-persistency' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (54 commits) d_make_discardable(): warn if given a non-persistent dentry kill securityfs_recursive_remove() convert securityfs get rid of kill_litter_super() convert rust_binderfs convert nfsctl convert rpc_pipefs convert hypfs hypfs: swich hypfs_create_u64() to returning int hypfs: switch hypfs_create_str() to returning int hypfs: don't pin dentries twice convert gadgetfs gadgetfs: switch to simple_remove_by_name() convert functionfs functionfs: switch to simple_remove_by_name() functionfs: fix the open/removal races functionfs: need to cancel ->reset_work in ->kill_sb() functionfs: don't bother with ffs->ref in ffs_data_{opened,closed}() functionfs: don't abuse ffs_data_closed() on fs shutdown convert selinuxfs ...

Merge tag 'lsm-pr-20251201' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm

2025-12-03T17:53:48Z

Pull LSM updates from Paul Moore: - Rework the LSM initialization code What started as a "quick" patch to enable a notification event once all of the individual LSMs were initialized, snowballed a bit into a 30+ patch patchset when everything was done. Most of the patches, and diffstat, is due to splitting out the initialization code into security/lsm_init.c and cleaning up some of the mess that was there. While not strictly necessary, it does cleanup the code signficantly, and hopefully makes the upkeep a bit easier in the future. Aside from the new LSM_STARTED_ALL notification, these changes also ensure that individual LSM initcalls are only called when the LSM is enabled at boot time. There should be a minor reduction in boot times for those who build multiple LSMs into their kernels, but only enable a subset at boot. It is worth mentioning that nothing at present makes use of the LSM_STARTED_ALL notification, but there is work in progress which is dependent upon LSM_STARTED_ALL. - Make better use of the seq_put*() helpers in device_cgroup * tag 'lsm-pr-20251201' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm: (36 commits) lsm: use unrcu_pointer() for current->cred in security_init() device_cgroup: Refactor devcgroup_seq_show to use seq_put* helpers lsm: add a LSM_STARTED_ALL notification event lsm: consolidate all of the LSM framework initcalls selinux: move initcalls to the LSM framework ima,evm: move initcalls to the LSM framework lockdown: move initcalls to the LSM framework apparmor: move initcalls to the LSM framework safesetid: move initcalls to the LSM framework tomoyo: move initcalls to the LSM framework smack: move initcalls to the LSM framework ipe: move initcalls to the LSM framework loadpin: move initcalls to the LSM framework lsm: introduce an initcall mechanism into the LSM framework lsm: group lsm_order_parse() with the other lsm_order_*() functions lsm: output available LSMs when debugging lsm: cleanup the debug and console output in lsm_init.c lsm: add/tweak function header comment blocks in lsm_init.c lsm: fold lsm_init_ordered() into security_init() lsm: cleanup initialize_lsm() and rename to lsm_init_single() ...

d_make_discardable(): warn if given a non-persistent dentry

2025-11-18T04:59:27Z

At this point there are very few call chains that might lead to d_make_discardable() on a dentry that hadn't been made persistent: calls of simple_unlink() and simple_rmdir() in configfs and apparmorfs. Both filesystems do pin (part of) their contents in dcache, but they are currently playing very unusual games with that. Converting them to more usual patterns might be possible, but it's definitely going to be a long series of changes in both cases. For now the easiest solution is to have both stop using simple_unlink() and simple_rmdir() - that allows to make d_make_discardable() warn when given a non-persistent dentry. Rather than giving them full-blown private copies (with calls of d_make_discardable() replaced with dput()), let's pull the parts of simple_unlink() and simple_rmdir() that deal with timestamps and link counts into separate helpers (__simple_unlink() and __simple_rmdir() resp.) and have those used by configfs and apparmorfs. Signed-off-by: Al Viro

VFS: introduce start_removing_dentry()

2025-11-14T12:15:57Z

start_removing_dentry() is similar to start_removing() but instead of providing a name for lookup, the target dentry is given. start_removing_dentry() checks that the dentry is still hashed and in the parent, and if so it locks and increases the refcount so that end_removing() can be used to finish the operation. This is used in cachefiles, overlayfs, smb/server, and apparmor. There will be other users including ecryptfs. As start_removing_dentry() takes an extra reference to the dentry (to be put by end_removing()), there is no need to explicitly take an extra reference to stop d_delete() from using dentry_unlink_inode() to negate the dentry - as in cachefiles_delete_object(), and ksmbd_vfs_unlink(). cachefiles_bury_object() now gets an extra ref to the victim, which is drops. As it includes the needed end_removing() calls, the caller doesn't need them. Reviewed-by: Amir Goldstein Reviewed-by: Namjae Jeon Reviewed-by: Jeff Layton Signed-off-by: NeilBrown Link: https://patch.msgid.link/20251113002050.676694-9-neilb@ownmail.net Signed-off-by: Christian Brauner

apparmor: move initcalls to the LSM framework

2025-10-22T23:24:27Z

Reviewed-by: Kees Cook Acked-by: John Johansen Signed-off-by: Paul Moore

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

2025-08-04T15:17:28Z

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 ...