linux-stable.git/security, branch v6.6.140

selinux: prune /sys/fs/selinux/disable

2026-05-17T15:13:38+00:00

commit 19cfa0099024bb9cd40f6d950caa7f47ff8e77f6 upstream.

Commit f22f9aaf6c3d ("selinux: remove the runtime disable
functionality") removed the underlying SELinux runtime disable
functionality but left everything else intact and started logging an
error message to warn any residual users.

Prune it to just log an error message once and to return count
(i.e. all bytes written successfully) to avoid breaking
userspace. This also fixes a local DoS from logspam.

Cc: stable@vger.kernel.org
Signed-off-by: Stephen Smalley 
Signed-off-by: Paul Moore 
Signed-off-by: Greg Kroah-Hartman

selinux: shrink critical section in sel_write_load()

2026-05-17T15:13:38+00:00

commit 868f31e4061eca8c3cd607d79d954d5e54f204aa upstream.

Currently sel_write_load() takes the policy mutex earlier than
necessary. Move the taking of the mutex later. This avoids
holding it unnecessarily across the vmalloc() and copy_from_user()
of the policy data.

Cc: stable@vger.kernel.org
Signed-off-by: Stephen Smalley 
Signed-off-by: Paul Moore 
Signed-off-by: Greg Kroah-Hartman

selinux: don't reserve xattr slot when we won't fill it

2026-05-17T15:13:38+00:00

commit 1e5a8eed7821e7a43a31b4c1b3675a91be6bc6f6 upstream.

Move lsm_get_xattr_slot() below the SBLABEL_MNT check so we don't leave
a NULL-named slot in the array when returning -EOPNOTSUPP; filesystem
initxattrs() callbacks stop iterating at the first NULL ->name, silently
dropping xattrs installed by later LSMs.

Cc: stable@vger.kernel.org
Signed-off-by: David Windsor 
Signed-off-by: Paul Moore 
Signed-off-by: Greg Kroah-Hartman

xen/privcmd: add boot control for restricted usage in domU

2026-03-25T10:06:10+00:00

commit 1613462be621ad5103ec338a7b0ca0746ec4e5f1 upstream.

When running in an unprivileged domU under Xen, the privcmd driver
is restricted to allow only hypercalls against a target domain, for
which the current domU is acting as a device model.

Add a boot parameter "unrestricted" to allow all hypercalls (the
hypervisor will still refuse destructive hypercalls affecting other
guests).

Make this new parameter effective only in case the domU wasn't started
using secure boot, as otherwise hypercalls targeting the domU itself
might result in violating the secure boot functionality.

This is achieved by adding another lockdown reason, which can be
tested to not being set when applying the "unrestricted" option.

This is part of XSA-482

Signed-off-by: Juergen Gross 
Signed-off-by: Greg Kroah-Hartman

apparmor: fix race between freeing data and fs accessing it

2026-03-25T10:05:43+00:00

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 and 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

2026-03-25T10:05:43+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 differential encoding verification

2026-03-25T10:05:43+00:00

commit 39440b137546a3aa383cfdabc605fb73811b6093 upstream.

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 
Signed-off-by: Greg Kroah-Hartman

apparmor: fix unprivileged local user can do privileged policy management

2026-03-25T10:05:43+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()

2026-03-25T10:05:43+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: fix missing bounds check on DEFAULT table in verify_dfa()

2026-03-25T10:05:43+00:00

commit d352873bbefa7eb39995239d0b44ccdf8aaa79a4 upstream.

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 
Signed-off-by: Greg Kroah-Hartman