linux-stable.git/kernel/audit.c, branch v5.10.261

audit: fix potential integer overflow in audit_log_n_hex()

2026-07-24T13:49:23+00:00

[ Upstream commit 65dfde57d1e29ce2b76fc23dd565eccd5c0bc0f0 ]

The function calculates new_len as len << 1 for hex encoding. This
has two overflow risks: the shift itself can overflow when len is
large, and the result can be truncated when assigned to new_len
(declared as int) from the size_t calculation.

Fix by using check_shl_overflow() to catch shift overflow and
changing new_len and loop counter i to size_t to prevent truncation.

Cc: stable@vger.kernel.org
Fixes: 168b7173959f ("AUDIT: Clean up logging of untrusted strings")
Reviewed-by: Richard Guy Briggs 
Signed-off-by: Ricardo Robaina 
[PM: remove vertical whitspace noise]
Signed-off-by: Paul Moore 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

audit: add audit_log_nf_skb helper function

2026-07-24T13:49:23+00:00

[ Upstream commit f19590b07cb620be1fcd5474c49515e21a05d406 ]

Netfilter code (net/netfilter/nft_log.c and net/netfilter/xt_AUDIT.c)
have to be kept in sync. Both source files had duplicated versions of
audit_ip4() and audit_ip6() functions, which can result in lack of
consistency and/or duplicated work.

This patch adds a helper function in audit.c that can be called by
netfilter code commonly, aiming to improve maintainability and
consistency.

Suggested-by: Florian Westphal 
Suggested-by: Paul Moore 
Signed-off-by: Ricardo Robaina 
Acked-by: Florian Westphal 
Signed-off-by: Paul Moore 
Stable-dep-of: 65dfde57d1e2 ("audit: fix potential integer overflow in audit_log_n_hex()")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

audit: Fix data races of skb_queue_len() readers on audit_queue

2026-07-24T13:48:49+00:00

commit c9a71daaecb2fb1d8c704545cc0b1c920b9bf5d7 upstream.

Multiple readers access audit_queue.qlen via skb_queue_len() without
holding the queue lock or using READ_ONCE(), while kauditd writes to
this field via the skb_dequeue() → __skb_unlink() path with WRITE_ONCE()
protected by a spinlock. This constitutes data races.

All affected skb_queue_len(&audit_queue) call sites:
  - kauditd_thread() wait_event_freezable() condition
  - audit_receive_msg() AUDIT_GET handler (s.backlog assignment)
  - audit_receive() backlog check
  - audit_log_start() backlog check and pr_warn()

KCSAN reports the following conflicting access pattern (one example):
==================================================================
BUG: KCSAN: data-race in audit_log_start / skb_dequeue

write (marked) to 0xffffffff8512ee20 of 4 bytes by task 661 on cpu 57:
 skb_dequeue+0x70/0xf0
 kauditd_send_queue+0x71/0x220
 kauditd_thread+0x1cb/0x430
 kthread+0x1c2/0x210
 ret_from_fork+0x162/0x1a0
 ret_from_fork_asm+0x1a/0x30

read to 0xffffffff8512ee20 of 4 bytes by task 36586 on cpu 1:
 audit_log_start+0x2a0/0x6b0
 audit_core_dumps+0x64/0xa0
 do_coredump+0x14b/0x1260
 get_signal+0xeb2/0xf70
 arch_do_signal_or_restart+0x41/0x170
 exit_to_user_mode_loop+0xa2/0x1c0
 do_syscall_64+0x1a3/0x1c0
 entry_SYSCALL_64_after_hwframe+0x76/0xe0

value changed: 0x00000001 -> 0x00000000
==================================================================

Resolve the race by switching to lockless helper skb_queue_len_lockless(),
which internally uses READ_ONCE() and properly pairs with the WRITE_ONCE()
write accesses already present on the writer side.

Cc: stable@vger.kernel.org
Fixes: 3197542482df ("audit: rework audit_log_start()")
Signed-off-by: Chi Wang 
Reviewed-by: Ricardo Robaina 
[PM: line length tweak]
Signed-off-by: Paul Moore 
Signed-off-by: Greg Kroah-Hartman

audit: enforce AUDIT_LOCKED for AUDIT_TRIM and AUDIT_MAKE_EQUIV

2026-06-01T15:29:47+00:00

commit f9e1c1324b4d98d591a6f7568fdebf5cf456dfc2 upstream.

AUDIT_ADD_RULE and AUDIT_DEL_RULE correctly check for AUDIT_LOCKED
and return -EPERM, but AUDIT_TRIM and AUDIT_MAKE_EQUIV do not. This
allows a process with CAP_AUDIT_CONTROL to modify directory tree
watches and equivalence mappings even when the audit configuration
has been locked, undermining the purpose of the lock.

Add AUDIT_LOCKED checks to both commands.

Cc: stable@vger.kernel.org
Reviewed-by: Ricardo Robaina 
Assisted-by: Claude:claude-opus-4-6
Signed-off-by: Sergio Correia 
Signed-off-by: Paul Moore 
Signed-off-by: Greg Kroah-Hartman

audit: Send netlink ACK before setting connection in auditd_set

2024-02-23T07:42:03+00:00

[ Upstream commit 022732e3d846e197539712e51ecada90ded0572a ]

When auditd_set sets the auditd_conn pointer, audit messages can
immediately be put on the socket by other kernel threads. If the backlog
is large or the rate is high, this can immediately fill the socket
buffer. If the audit daemon requested an ACK for this operation, a full
socket buffer causes the ACK to get dropped, also setting ENOBUFS on the
socket.

To avoid this race and ensure ACKs get through, fast-track the ACK in
this specific case to ensure it is sent before auditd_conn is set.

Signed-off-by: Chris Riches 
[PM: fix some tab vs space damage]
Signed-off-by: Paul Moore 
Signed-off-by: Sasha Levin

audit: improve audit queue handling when "audit=1" on cmdline

2022-02-08T17:30:34+00:00

commit f26d04331360d42dbd6b58448bd98e4edbfbe1c5 upstream.

When an admin enables audit at early boot via the "audit=1" kernel
command line the audit queue behavior is slightly different; the
audit subsystem goes to greater lengths to avoid dropping records,
which unfortunately can result in problems when the audit daemon is
forcibly stopped for an extended period of time.

This patch makes a number of changes designed to improve the audit
queuing behavior so that leaving the audit daemon in a stopped state
for an extended period does not cause a significant impact to the
system.

- kauditd_send_queue() is now limited to looping through the
  passed queue only once per call.  This not only prevents the
  function from looping indefinitely when records are returned
  to the current queue, it also allows any recovery handling in
  kauditd_thread() to take place when kauditd_send_queue()
  returns.

- Transient netlink send errors seen as -EAGAIN now cause the
  record to be returned to the retry queue instead of going to
  the hold queue.  The intention of the hold queue is to store,
  perhaps for an extended period of time, the events which led
  up to the audit daemon going offline.  The retry queue remains
  a temporary queue intended to protect against transient issues
  between the kernel and the audit daemon.

- The retry queue is now limited by the audit_backlog_limit
  setting, the same as the other queues.  This allows admins
  to bound the size of all of the audit queues on the system.

- kauditd_rehold_skb() now returns records to the end of the
  hold queue to ensure ordering is preserved in the face of
  recent changes to kauditd_send_queue().

Cc: stable@vger.kernel.org
Fixes: 5b52330bbfe63 ("audit: fix auditd/kernel connection state tracking")
Fixes: f4b3ee3c85551 ("audit: improve robustness of the audit queue handling")
Reported-by: Gaosheng Cui 
Tested-by: Gaosheng Cui 
Reviewed-by: Richard Guy Briggs 
Signed-off-by: Paul Moore 
Signed-off-by: Greg Kroah-Hartman

audit: ensure userspace is penalized the same as the kernel when under pressure

2022-01-27T09:54:16+00:00

[ Upstream commit 8f110f530635af44fff1f4ee100ecef0bac62510 ]

Due to the audit control mutex necessary for serializing audit
userspace messages we haven't been able to block/penalize userspace
processes that attempt to send audit records while the system is
under audit pressure.  The result is that privileged userspace
applications have a priority boost with respect to audit as they are
not bound by the same audit queue throttling as the other tasks on
the system.

This patch attempts to restore some balance to the system when under
audit pressure by blocking these privileged userspace tasks after
they have finished their audit processing, and dropped the audit
control mutex, but before they return to userspace.

Reported-by: Gaosheng Cui 
Tested-by: Gaosheng Cui 
Reviewed-by: Richard Guy Briggs 
Signed-off-by: Paul Moore 
Signed-off-by: Sasha Levin

audit: improve robustness of the audit queue handling

2021-12-22T08:30:51+00:00

commit f4b3ee3c85551d2d343a3ba159304066523f730f upstream.

If the audit daemon were ever to get stuck in a stopped state the
kernel's kauditd_thread() could get blocked attempting to send audit
records to the userspace audit daemon.  With the kernel thread
blocked it is possible that the audit queue could grow unbounded as
certain audit record generating events must be exempt from the queue
limits else the system enter a deadlock state.

This patch resolves this problem by lowering the kernel thread's
socket sending timeout from MAX_SCHEDULE_TIMEOUT to HZ/10 and tweaks
the kauditd_send_queue() function to better manage the various audit
queues when connection problems occur between the kernel and the
audit daemon.  With this patch, the backlog may temporarily grow
beyond the defined limits when the audit daemon is stopped and the
system is under heavy audit pressure, but kauditd_thread() will
continue to make progress and drain the queues as it would for other
connection problems.  For example, with the audit daemon put into a
stopped state and the system configured to audit every syscall it
was still possible to shutdown the system without a kernel panic,
deadlock, etc.; granted, the system was slow to shutdown but that is
to be expected given the extreme pressure of recording every syscall.

The timeout value of HZ/10 was chosen primarily through
experimentation and this developer's "gut feeling".  There is likely
no one perfect value, but as this scenario is limited in scope (root
privileges would be needed to send SIGSTOP to the audit daemon), it
is likely not worth exposing this as a tunable at present.  This can
always be done at a later date if it proves necessary.

Cc: stable@vger.kernel.org
Fixes: 5b52330bbfe63 ("audit: fix auditd/kernel connection state tracking")
Reported-by: Gaosheng Cui 
Tested-by: Gaosheng Cui 
Reviewed-by: Richard Guy Briggs 
Signed-off-by: Paul Moore 
Signed-off-by: Greg Kroah-Hartman

audit: Remove redundant null check

2020-08-26T13:10:39+00:00

Because kfree_skb already checked NULL skb parameter,
so the additional check is unnecessary, just remove it.

Signed-off-by: Xu Wang 
Signed-off-by: Paul Moore

audit: uninitialize variable audit_sig_sid

2020-08-18T00:28:17+00:00

Checkpatch tool reports

"ERROR: do not initialise globals/statics to 0"

To fix this, audit_sig_sid is uninitialized
As this is stored in the .bss section,
the compiler can initialize the variable automatically.

Signed-off-by: Jules Irenge 
Signed-off-by: Paul Moore