1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* audit.c -- Auditing support
3 * Gateway between the kernel (e.g., selinux) and the user-space audit daemon.
4 * System-call specific features have moved to auditsc.c
6 * Copyright 2003-2007 Red Hat Inc., Durham, North Carolina.
9 * Written by Rickard E. (Rik) Faith <faith@redhat.com>
11 * Goals: 1) Integrate fully with Security Modules.
12 * 2) Minimal run-time overhead:
13 * a) Minimal when syscall auditing is disabled (audit_enable=0).
14 * b) Small when syscall auditing is enabled and no audit record
15 * is generated (defer as much work as possible to record
17 * i) context is allocated,
18 * ii) names from getname are stored without a copy, and
19 * iii) inode information stored from path_lookup.
20 * 3) Ability to disable syscall auditing at boot time (audit=0).
21 * 4) Usable by other parts of the kernel (if audit_log* is called,
22 * then a syscall record will be generated automatically for the
24 * 5) Netlink interface to user-space.
25 * 6) Support low-overhead kernel-based filtering to minimize the
26 * information that must be passed to user-space.
28 * Audit userspace, documentation, tests, and bug/issue trackers:
29 * https://github.com/linux-audit
32 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
34 #include <linux/file.h>
35 #include <linux/init.h>
36 #include <linux/types.h>
37 #include <linux/atomic.h>
39 #include <linux/export.h>
40 #include <linux/slab.h>
41 #include <linux/err.h>
42 #include <linux/kthread.h>
43 #include <linux/kernel.h>
44 #include <linux/syscalls.h>
45 #include <linux/spinlock.h>
46 #include <linux/rcupdate.h>
47 #include <linux/mutex.h>
48 #include <linux/gfp.h>
49 #include <linux/pid.h>
51 #include <linux/audit.h>
54 #include <net/netlink.h>
55 #include <linux/skbuff.h>
56 #ifdef CONFIG_SECURITY
57 #include <linux/security.h>
59 #include <linux/freezer.h>
60 #include <linux/pid_namespace.h>
61 #include <net/netns/generic.h>
65 /* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
66 * (Initialization happens after skb_init is called.) */
67 #define AUDIT_DISABLED -1
68 #define AUDIT_UNINITIALIZED 0
69 #define AUDIT_INITIALIZED 1
70 static int audit_initialized
= AUDIT_UNINITIALIZED
;
72 u32 audit_enabled
= AUDIT_OFF
;
73 bool audit_ever_enabled
= !!AUDIT_OFF
;
75 EXPORT_SYMBOL_GPL(audit_enabled
);
77 /* Default state when kernel boots without any parameters. */
78 static u32 audit_default
= AUDIT_OFF
;
80 /* If auditing cannot proceed, audit_failure selects what happens. */
81 static u32 audit_failure
= AUDIT_FAIL_PRINTK
;
83 /* private audit network namespace index */
84 static unsigned int audit_net_id
;
87 * struct audit_net - audit private network namespace data
88 * @sk: communication socket
95 * struct auditd_connection - kernel/auditd connection state
97 * @portid: netlink portid
98 * @net: the associated network namespace
102 * This struct is RCU protected; you must either hold the RCU lock for reading
103 * or the associated spinlock for writing.
105 struct auditd_connection
{
111 static struct auditd_connection __rcu
*auditd_conn
;
112 static DEFINE_SPINLOCK(auditd_conn_lock
);
114 /* If audit_rate_limit is non-zero, limit the rate of sending audit records
115 * to that number per second. This prevents DoS attacks, but results in
116 * audit records being dropped. */
117 static u32 audit_rate_limit
;
119 /* Number of outstanding audit_buffers allowed.
120 * When set to zero, this means unlimited. */
121 static u32 audit_backlog_limit
= 64;
122 #define AUDIT_BACKLOG_WAIT_TIME (60 * HZ)
123 static u32 audit_backlog_wait_time
= AUDIT_BACKLOG_WAIT_TIME
;
125 /* The identity of the user shutting down the audit system. */
126 static kuid_t audit_sig_uid
= INVALID_UID
;
127 static pid_t audit_sig_pid
= -1;
128 static u32 audit_sig_sid
;
130 /* Records can be lost in several ways:
131 0) [suppressed in audit_alloc]
132 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
133 2) out of memory in audit_log_move [alloc_skb]
134 3) suppressed due to audit_rate_limit
135 4) suppressed due to audit_backlog_limit
137 static atomic_t audit_lost
= ATOMIC_INIT(0);
139 /* Monotonically increasing sum of time the kernel has spent
140 * waiting while the backlog limit is exceeded.
142 static atomic_t audit_backlog_wait_time_actual
= ATOMIC_INIT(0);
144 /* Hash for inode-based rules */
145 struct list_head audit_inode_hash
[AUDIT_INODE_BUCKETS
];
147 static struct kmem_cache
*audit_buffer_cache
;
149 /* queue msgs to send via kauditd_task */
150 static struct sk_buff_head audit_queue
;
151 /* queue msgs due to temporary unicast send problems */
152 static struct sk_buff_head audit_retry_queue
;
153 /* queue msgs waiting for new auditd connection */
154 static struct sk_buff_head audit_hold_queue
;
156 /* queue servicing thread */
157 static struct task_struct
*kauditd_task
;
158 static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait
);
160 /* waitqueue for callers who are blocked on the audit backlog */
161 static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait
);
163 static struct audit_features af
= {.vers
= AUDIT_FEATURE_VERSION
,
168 static char *audit_feature_names
[2] = {
169 "only_unset_loginuid",
170 "loginuid_immutable",
174 * struct audit_ctl_mutex - serialize requests from userspace
175 * @lock: the mutex used for locking
176 * @owner: the task which owns the lock
179 * This is the lock struct used to ensure we only process userspace requests
180 * in an orderly fashion. We can't simply use a mutex/lock here because we
181 * need to track lock ownership so we don't end up blocking the lock owner in
182 * audit_log_start() or similar.
184 static struct audit_ctl_mutex
{
189 /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
190 * audit records. Since printk uses a 1024 byte buffer, this buffer
191 * should be at least that large. */
192 #define AUDIT_BUFSIZ 1024
194 /* The audit_buffer is used when formatting an audit record. The caller
195 * locks briefly to get the record off the freelist or to allocate the
196 * buffer, and locks briefly to send the buffer to the netlink layer or
197 * to place it on a transmit queue. Multiple audit_buffers can be in
198 * use simultaneously. */
199 struct audit_buffer
{
200 struct sk_buff
*skb
; /* formatted skb ready to send */
201 struct audit_context
*ctx
; /* NULL or associated context */
212 * auditd_test_task - Check to see if a given task is an audit daemon
213 * @task: the task to check
216 * Return 1 if the task is a registered audit daemon, 0 otherwise.
218 int auditd_test_task(struct task_struct
*task
)
221 struct auditd_connection
*ac
;
224 ac
= rcu_dereference(auditd_conn
);
225 rc
= (ac
&& ac
->pid
== task_tgid(task
) ? 1 : 0);
232 * audit_ctl_lock - Take the audit control lock
234 void audit_ctl_lock(void)
236 mutex_lock(&audit_cmd_mutex
.lock
);
237 audit_cmd_mutex
.owner
= current
;
241 * audit_ctl_unlock - Drop the audit control lock
243 void audit_ctl_unlock(void)
245 audit_cmd_mutex
.owner
= NULL
;
246 mutex_unlock(&audit_cmd_mutex
.lock
);
250 * audit_ctl_owner_current - Test to see if the current task owns the lock
253 * Return true if the current task owns the audit control lock, false if it
254 * doesn't own the lock.
256 static bool audit_ctl_owner_current(void)
258 return (current
== audit_cmd_mutex
.owner
);
262 * auditd_pid_vnr - Return the auditd PID relative to the namespace
265 * Returns the PID in relation to the namespace, 0 on failure.
267 static pid_t
auditd_pid_vnr(void)
270 const struct auditd_connection
*ac
;
273 ac
= rcu_dereference(auditd_conn
);
277 pid
= pid_vnr(ac
->pid
);
284 * audit_get_sk - Return the audit socket for the given network namespace
285 * @net: the destination network namespace
288 * Returns the sock pointer if valid, NULL otherwise. The caller must ensure
289 * that a reference is held for the network namespace while the sock is in use.
291 static struct sock
*audit_get_sk(const struct net
*net
)
293 struct audit_net
*aunet
;
298 aunet
= net_generic(net
, audit_net_id
);
302 void audit_panic(const char *message
)
304 switch (audit_failure
) {
305 case AUDIT_FAIL_SILENT
:
307 case AUDIT_FAIL_PRINTK
:
308 if (printk_ratelimit())
309 pr_err("%s\n", message
);
311 case AUDIT_FAIL_PANIC
:
312 panic("audit: %s\n", message
);
317 static inline int audit_rate_check(void)
319 static unsigned long last_check
= 0;
320 static int messages
= 0;
321 static DEFINE_SPINLOCK(lock
);
326 if (!audit_rate_limit
) return 1;
328 spin_lock_irqsave(&lock
, flags
);
329 if (++messages
< audit_rate_limit
) {
333 if (time_after(now
, last_check
+ HZ
)) {
339 spin_unlock_irqrestore(&lock
, flags
);
345 * audit_log_lost - conditionally log lost audit message event
346 * @message: the message stating reason for lost audit message
348 * Emit at least 1 message per second, even if audit_rate_check is
350 * Always increment the lost messages counter.
352 void audit_log_lost(const char *message
)
354 static unsigned long last_msg
= 0;
355 static DEFINE_SPINLOCK(lock
);
360 atomic_inc(&audit_lost
);
362 print
= (audit_failure
== AUDIT_FAIL_PANIC
|| !audit_rate_limit
);
365 spin_lock_irqsave(&lock
, flags
);
367 if (time_after(now
, last_msg
+ HZ
)) {
371 spin_unlock_irqrestore(&lock
, flags
);
375 if (printk_ratelimit())
376 pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
377 atomic_read(&audit_lost
),
379 audit_backlog_limit
);
380 audit_panic(message
);
384 static int audit_log_config_change(char *function_name
, u32
new, u32 old
,
387 struct audit_buffer
*ab
;
390 ab
= audit_log_start(audit_context(), GFP_KERNEL
, AUDIT_CONFIG_CHANGE
);
393 audit_log_format(ab
, "op=set %s=%u old=%u ", function_name
, new, old
);
394 audit_log_session_info(ab
);
395 rc
= audit_log_task_context(ab
);
397 allow_changes
= 0; /* Something weird, deny request */
398 audit_log_format(ab
, " res=%d", allow_changes
);
403 static int audit_do_config_change(char *function_name
, u32
*to_change
, u32
new)
405 int allow_changes
, rc
= 0;
406 u32 old
= *to_change
;
408 /* check if we are locked */
409 if (audit_enabled
== AUDIT_LOCKED
)
414 if (audit_enabled
!= AUDIT_OFF
) {
415 rc
= audit_log_config_change(function_name
, new, old
, allow_changes
);
420 /* If we are allowed, make the change */
421 if (allow_changes
== 1)
423 /* Not allowed, update reason */
429 static int audit_set_rate_limit(u32 limit
)
431 return audit_do_config_change("audit_rate_limit", &audit_rate_limit
, limit
);
434 static int audit_set_backlog_limit(u32 limit
)
436 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit
, limit
);
439 static int audit_set_backlog_wait_time(u32 timeout
)
441 return audit_do_config_change("audit_backlog_wait_time",
442 &audit_backlog_wait_time
, timeout
);
445 static int audit_set_enabled(u32 state
)
448 if (state
> AUDIT_LOCKED
)
451 rc
= audit_do_config_change("audit_enabled", &audit_enabled
, state
);
453 audit_ever_enabled
|= !!state
;
458 static int audit_set_failure(u32 state
)
460 if (state
!= AUDIT_FAIL_SILENT
461 && state
!= AUDIT_FAIL_PRINTK
462 && state
!= AUDIT_FAIL_PANIC
)
465 return audit_do_config_change("audit_failure", &audit_failure
, state
);
469 * auditd_conn_free - RCU helper to release an auditd connection struct
473 * Drop any references inside the auditd connection tracking struct and free
476 static void auditd_conn_free(struct rcu_head
*rcu
)
478 struct auditd_connection
*ac
;
480 ac
= container_of(rcu
, struct auditd_connection
, rcu
);
487 * auditd_set - Set/Reset the auditd connection state
489 * @portid: auditd netlink portid
490 * @net: auditd network namespace pointer
493 * This function will obtain and drop network namespace references as
494 * necessary. Returns zero on success, negative values on failure.
496 static int auditd_set(struct pid
*pid
, u32 portid
, struct net
*net
)
499 struct auditd_connection
*ac_old
, *ac_new
;
504 ac_new
= kzalloc(sizeof(*ac_new
), GFP_KERNEL
);
507 ac_new
->pid
= get_pid(pid
);
508 ac_new
->portid
= portid
;
509 ac_new
->net
= get_net(net
);
511 spin_lock_irqsave(&auditd_conn_lock
, flags
);
512 ac_old
= rcu_dereference_protected(auditd_conn
,
513 lockdep_is_held(&auditd_conn_lock
));
514 rcu_assign_pointer(auditd_conn
, ac_new
);
515 spin_unlock_irqrestore(&auditd_conn_lock
, flags
);
518 call_rcu(&ac_old
->rcu
, auditd_conn_free
);
524 * kauditd_printk_skb - Print the audit record to the ring buffer
527 * Whatever the reason, this packet may not make it to the auditd connection
528 * so write it via printk so the information isn't completely lost.
530 static void kauditd_printk_skb(struct sk_buff
*skb
)
532 struct nlmsghdr
*nlh
= nlmsg_hdr(skb
);
533 char *data
= nlmsg_data(nlh
);
535 if (nlh
->nlmsg_type
!= AUDIT_EOE
&& printk_ratelimit())
536 pr_notice("type=%d %s\n", nlh
->nlmsg_type
, data
);
540 * kauditd_rehold_skb - Handle a audit record send failure in the hold queue
542 * @error: error code (unused)
545 * This should only be used by the kauditd_thread when it fails to flush the
548 static void kauditd_rehold_skb(struct sk_buff
*skb
, __always_unused
int error
)
550 /* put the record back in the queue */
551 skb_queue_tail(&audit_hold_queue
, skb
);
555 * kauditd_hold_skb - Queue an audit record, waiting for auditd
560 * Queue the audit record, waiting for an instance of auditd. When this
561 * function is called we haven't given up yet on sending the record, but things
562 * are not looking good. The first thing we want to do is try to write the
563 * record via printk and then see if we want to try and hold on to the record
564 * and queue it, if we have room. If we want to hold on to the record, but we
565 * don't have room, record a record lost message.
567 static void kauditd_hold_skb(struct sk_buff
*skb
, int error
)
569 /* at this point it is uncertain if we will ever send this to auditd so
570 * try to send the message via printk before we go any further */
571 kauditd_printk_skb(skb
);
573 /* can we just silently drop the message? */
577 /* the hold queue is only for when the daemon goes away completely,
578 * not -EAGAIN failures; if we are in a -EAGAIN state requeue the
579 * record on the retry queue unless it's full, in which case drop it
581 if (error
== -EAGAIN
) {
582 if (!audit_backlog_limit
||
583 skb_queue_len(&audit_retry_queue
) < audit_backlog_limit
) {
584 skb_queue_tail(&audit_retry_queue
, skb
);
587 audit_log_lost("kauditd retry queue overflow");
591 /* if we have room in the hold queue, queue the message */
592 if (!audit_backlog_limit
||
593 skb_queue_len(&audit_hold_queue
) < audit_backlog_limit
) {
594 skb_queue_tail(&audit_hold_queue
, skb
);
598 /* we have no other options - drop the message */
599 audit_log_lost("kauditd hold queue overflow");
605 * kauditd_retry_skb - Queue an audit record, attempt to send again to auditd
607 * @error: error code (unused)
610 * Not as serious as kauditd_hold_skb() as we still have a connected auditd,
611 * but for some reason we are having problems sending it audit records so
612 * queue the given record and attempt to resend.
614 static void kauditd_retry_skb(struct sk_buff
*skb
, __always_unused
int error
)
616 if (!audit_backlog_limit
||
617 skb_queue_len(&audit_retry_queue
) < audit_backlog_limit
) {
618 skb_queue_tail(&audit_retry_queue
, skb
);
622 /* we have to drop the record, send it via printk as a last effort */
623 kauditd_printk_skb(skb
);
624 audit_log_lost("kauditd retry queue overflow");
629 * auditd_reset - Disconnect the auditd connection
630 * @ac: auditd connection state
633 * Break the auditd/kauditd connection and move all the queued records into the
634 * hold queue in case auditd reconnects. It is important to note that the @ac
635 * pointer should never be dereferenced inside this function as it may be NULL
636 * or invalid, you can only compare the memory address! If @ac is NULL then
637 * the connection will always be reset.
639 static void auditd_reset(const struct auditd_connection
*ac
)
643 struct auditd_connection
*ac_old
;
645 /* if it isn't already broken, break the connection */
646 spin_lock_irqsave(&auditd_conn_lock
, flags
);
647 ac_old
= rcu_dereference_protected(auditd_conn
,
648 lockdep_is_held(&auditd_conn_lock
));
649 if (ac
&& ac
!= ac_old
) {
650 /* someone already registered a new auditd connection */
651 spin_unlock_irqrestore(&auditd_conn_lock
, flags
);
654 rcu_assign_pointer(auditd_conn
, NULL
);
655 spin_unlock_irqrestore(&auditd_conn_lock
, flags
);
658 call_rcu(&ac_old
->rcu
, auditd_conn_free
);
660 /* flush the retry queue to the hold queue, but don't touch the main
661 * queue since we need to process that normally for multicast */
662 while ((skb
= skb_dequeue(&audit_retry_queue
)))
663 kauditd_hold_skb(skb
, -ECONNREFUSED
);
667 * auditd_send_unicast_skb - Send a record via unicast to auditd
671 * Send a skb to the audit daemon, returns positive/zero values on success and
672 * negative values on failure; in all cases the skb will be consumed by this
673 * function. If the send results in -ECONNREFUSED the connection with auditd
674 * will be reset. This function may sleep so callers should not hold any locks
675 * where this would cause a problem.
677 static int auditd_send_unicast_skb(struct sk_buff
*skb
)
683 struct auditd_connection
*ac
;
685 /* NOTE: we can't call netlink_unicast while in the RCU section so
686 * take a reference to the network namespace and grab local
687 * copies of the namespace, the sock, and the portid; the
688 * namespace and sock aren't going to go away while we hold a
689 * reference and if the portid does become invalid after the RCU
690 * section netlink_unicast() should safely return an error */
693 ac
= rcu_dereference(auditd_conn
);
700 net
= get_net(ac
->net
);
701 sk
= audit_get_sk(net
);
705 rc
= netlink_unicast(sk
, skb
, portid
, 0);
713 if (ac
&& rc
== -ECONNREFUSED
)
719 * kauditd_send_queue - Helper for kauditd_thread to flush skb queues
720 * @sk: the sending sock
721 * @portid: the netlink destination
722 * @queue: the skb queue to process
723 * @retry_limit: limit on number of netlink unicast failures
724 * @skb_hook: per-skb hook for additional processing
725 * @err_hook: hook called if the skb fails the netlink unicast send
728 * Run through the given queue and attempt to send the audit records to auditd,
729 * returns zero on success, negative values on failure. It is up to the caller
730 * to ensure that the @sk is valid for the duration of this function.
733 static int kauditd_send_queue(struct sock
*sk
, u32 portid
,
734 struct sk_buff_head
*queue
,
735 unsigned int retry_limit
,
736 void (*skb_hook
)(struct sk_buff
*skb
),
737 void (*err_hook
)(struct sk_buff
*skb
, int error
))
740 struct sk_buff
*skb
= NULL
;
741 struct sk_buff
*skb_tail
;
742 unsigned int failed
= 0;
744 /* NOTE: kauditd_thread takes care of all our locking, we just use
745 * the netlink info passed to us (e.g. sk and portid) */
747 skb_tail
= skb_peek_tail(queue
);
748 while ((skb
!= skb_tail
) && (skb
= skb_dequeue(queue
))) {
749 /* call the skb_hook for each skb we touch */
753 /* can we send to anyone via unicast? */
756 (*err_hook
)(skb
, -ECONNREFUSED
);
761 /* grab an extra skb reference in case of error */
763 rc
= netlink_unicast(sk
, skb
, portid
, 0);
765 /* send failed - try a few times unless fatal error */
766 if (++failed
>= retry_limit
||
767 rc
== -ECONNREFUSED
|| rc
== -EPERM
) {
770 (*err_hook
)(skb
, rc
);
773 /* continue to drain the queue */
778 /* skb sent - drop the extra reference and continue */
784 return (rc
>= 0 ? 0 : rc
);
788 * kauditd_send_multicast_skb - Send a record to any multicast listeners
792 * Write a multicast message to anyone listening in the initial network
793 * namespace. This function doesn't consume an skb as might be expected since
794 * it has to copy it anyways.
796 static void kauditd_send_multicast_skb(struct sk_buff
*skb
)
798 struct sk_buff
*copy
;
799 struct sock
*sock
= audit_get_sk(&init_net
);
800 struct nlmsghdr
*nlh
;
802 /* NOTE: we are not taking an additional reference for init_net since
803 * we don't have to worry about it going away */
805 if (!netlink_has_listeners(sock
, AUDIT_NLGRP_READLOG
))
809 * The seemingly wasteful skb_copy() rather than bumping the refcount
810 * using skb_get() is necessary because non-standard mods are made to
811 * the skb by the original kaudit unicast socket send routine. The
812 * existing auditd daemon assumes this breakage. Fixing this would
813 * require co-ordinating a change in the established protocol between
814 * the kaudit kernel subsystem and the auditd userspace code. There is
815 * no reason for new multicast clients to continue with this
818 copy
= skb_copy(skb
, GFP_KERNEL
);
821 nlh
= nlmsg_hdr(copy
);
822 nlh
->nlmsg_len
= skb
->len
;
824 nlmsg_multicast(sock
, copy
, 0, AUDIT_NLGRP_READLOG
, GFP_KERNEL
);
828 * kauditd_thread - Worker thread to send audit records to userspace
831 static int kauditd_thread(void *dummy
)
835 struct net
*net
= NULL
;
836 struct sock
*sk
= NULL
;
837 struct auditd_connection
*ac
;
839 #define UNICAST_RETRIES 5
842 while (!kthread_should_stop()) {
843 /* NOTE: see the lock comments in auditd_send_unicast_skb() */
845 ac
= rcu_dereference(auditd_conn
);
850 net
= get_net(ac
->net
);
851 sk
= audit_get_sk(net
);
855 /* attempt to flush the hold queue */
856 rc
= kauditd_send_queue(sk
, portid
,
857 &audit_hold_queue
, UNICAST_RETRIES
,
858 NULL
, kauditd_rehold_skb
);
865 /* attempt to flush the retry queue */
866 rc
= kauditd_send_queue(sk
, portid
,
867 &audit_retry_queue
, UNICAST_RETRIES
,
868 NULL
, kauditd_hold_skb
);
876 /* process the main queue - do the multicast send and attempt
877 * unicast, dump failed record sends to the retry queue; if
878 * sk == NULL due to previous failures we will just do the
879 * multicast send and move the record to the hold queue */
880 rc
= kauditd_send_queue(sk
, portid
, &audit_queue
, 1,
881 kauditd_send_multicast_skb
,
883 kauditd_retry_skb
: kauditd_hold_skb
));
888 /* drop our netns reference, no auditd sends past this line */
894 /* we have processed all the queues so wake everyone */
895 wake_up(&audit_backlog_wait
);
897 /* NOTE: we want to wake up if there is anything on the queue,
898 * regardless of if an auditd is connected, as we need to
899 * do the multicast send and rotate records from the
900 * main queue to the retry/hold queues */
901 wait_event_freezable(kauditd_wait
,
902 (skb_queue_len(&audit_queue
) ? 1 : 0));
908 int audit_send_list_thread(void *_dest
)
910 struct audit_netlink_list
*dest
= _dest
;
912 struct sock
*sk
= audit_get_sk(dest
->net
);
914 /* wait for parent to finish and send an ACK */
918 while ((skb
= __skb_dequeue(&dest
->q
)) != NULL
)
919 netlink_unicast(sk
, skb
, dest
->portid
, 0);
927 struct sk_buff
*audit_make_reply(int seq
, int type
, int done
,
928 int multi
, const void *payload
, int size
)
931 struct nlmsghdr
*nlh
;
933 int flags
= multi
? NLM_F_MULTI
: 0;
934 int t
= done
? NLMSG_DONE
: type
;
936 skb
= nlmsg_new(size
, GFP_KERNEL
);
940 nlh
= nlmsg_put(skb
, 0, seq
, t
, size
, flags
);
943 data
= nlmsg_data(nlh
);
944 memcpy(data
, payload
, size
);
952 static void audit_free_reply(struct audit_reply
*reply
)
957 kfree_skb(reply
->skb
);
963 static int audit_send_reply_thread(void *arg
)
965 struct audit_reply
*reply
= (struct audit_reply
*)arg
;
970 /* Ignore failure. It'll only happen if the sender goes away,
971 because our timeout is set to infinite. */
972 netlink_unicast(audit_get_sk(reply
->net
), reply
->skb
, reply
->portid
, 0);
974 audit_free_reply(reply
);
979 * audit_send_reply - send an audit reply message via netlink
980 * @request_skb: skb of request we are replying to (used to target the reply)
981 * @seq: sequence number
982 * @type: audit message type
983 * @done: done (last) flag
984 * @multi: multi-part message flag
985 * @payload: payload data
986 * @size: payload size
988 * Allocates a skb, builds the netlink message, and sends it to the port id.
990 static void audit_send_reply(struct sk_buff
*request_skb
, int seq
, int type
, int done
,
991 int multi
, const void *payload
, int size
)
993 struct task_struct
*tsk
;
994 struct audit_reply
*reply
;
996 reply
= kzalloc(sizeof(*reply
), GFP_KERNEL
);
1000 reply
->skb
= audit_make_reply(seq
, type
, done
, multi
, payload
, size
);
1003 reply
->net
= get_net(sock_net(NETLINK_CB(request_skb
).sk
));
1004 reply
->portid
= NETLINK_CB(request_skb
).portid
;
1006 tsk
= kthread_run(audit_send_reply_thread
, reply
, "audit_send_reply");
1013 audit_free_reply(reply
);
1017 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
1020 static int audit_netlink_ok(struct sk_buff
*skb
, u16 msg_type
)
1024 /* Only support initial user namespace for now. */
1026 * We return ECONNREFUSED because it tricks userspace into thinking
1027 * that audit was not configured into the kernel. Lots of users
1028 * configure their PAM stack (because that's what the distro does)
1029 * to reject login if unable to send messages to audit. If we return
1030 * ECONNREFUSED the PAM stack thinks the kernel does not have audit
1031 * configured in and will let login proceed. If we return EPERM
1032 * userspace will reject all logins. This should be removed when we
1033 * support non init namespaces!!
1035 if (current_user_ns() != &init_user_ns
)
1036 return -ECONNREFUSED
;
1045 case AUDIT_GET_FEATURE
:
1046 case AUDIT_SET_FEATURE
:
1047 case AUDIT_LIST_RULES
:
1048 case AUDIT_ADD_RULE
:
1049 case AUDIT_DEL_RULE
:
1050 case AUDIT_SIGNAL_INFO
:
1054 case AUDIT_MAKE_EQUIV
:
1055 /* Only support auditd and auditctl in initial pid namespace
1057 if (task_active_pid_ns(current
) != &init_pid_ns
)
1060 if (!netlink_capable(skb
, CAP_AUDIT_CONTROL
))
1064 case AUDIT_FIRST_USER_MSG
... AUDIT_LAST_USER_MSG
:
1065 case AUDIT_FIRST_USER_MSG2
... AUDIT_LAST_USER_MSG2
:
1066 if (!netlink_capable(skb
, CAP_AUDIT_WRITE
))
1069 default: /* bad msg */
1076 static void audit_log_common_recv_msg(struct audit_context
*context
,
1077 struct audit_buffer
**ab
, u16 msg_type
)
1079 uid_t uid
= from_kuid(&init_user_ns
, current_uid());
1080 pid_t pid
= task_tgid_nr(current
);
1082 if (!audit_enabled
&& msg_type
!= AUDIT_USER_AVC
) {
1087 *ab
= audit_log_start(context
, GFP_KERNEL
, msg_type
);
1090 audit_log_format(*ab
, "pid=%d uid=%u ", pid
, uid
);
1091 audit_log_session_info(*ab
);
1092 audit_log_task_context(*ab
);
1095 static inline void audit_log_user_recv_msg(struct audit_buffer
**ab
,
1098 audit_log_common_recv_msg(NULL
, ab
, msg_type
);
1101 static int is_audit_feature_set(int i
)
1103 return af
.features
& AUDIT_FEATURE_TO_MASK(i
);
1107 static int audit_get_feature(struct sk_buff
*skb
)
1111 seq
= nlmsg_hdr(skb
)->nlmsg_seq
;
1113 audit_send_reply(skb
, seq
, AUDIT_GET_FEATURE
, 0, 0, &af
, sizeof(af
));
1118 static void audit_log_feature_change(int which
, u32 old_feature
, u32 new_feature
,
1119 u32 old_lock
, u32 new_lock
, int res
)
1121 struct audit_buffer
*ab
;
1123 if (audit_enabled
== AUDIT_OFF
)
1126 ab
= audit_log_start(audit_context(), GFP_KERNEL
, AUDIT_FEATURE_CHANGE
);
1129 audit_log_task_info(ab
);
1130 audit_log_format(ab
, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
1131 audit_feature_names
[which
], !!old_feature
, !!new_feature
,
1132 !!old_lock
, !!new_lock
, res
);
1136 static int audit_set_feature(struct audit_features
*uaf
)
1140 BUILD_BUG_ON(AUDIT_LAST_FEATURE
+ 1 > ARRAY_SIZE(audit_feature_names
));
1142 /* if there is ever a version 2 we should handle that here */
1144 for (i
= 0; i
<= AUDIT_LAST_FEATURE
; i
++) {
1145 u32 feature
= AUDIT_FEATURE_TO_MASK(i
);
1146 u32 old_feature
, new_feature
, old_lock
, new_lock
;
1148 /* if we are not changing this feature, move along */
1149 if (!(feature
& uaf
->mask
))
1152 old_feature
= af
.features
& feature
;
1153 new_feature
= uaf
->features
& feature
;
1154 new_lock
= (uaf
->lock
| af
.lock
) & feature
;
1155 old_lock
= af
.lock
& feature
;
1157 /* are we changing a locked feature? */
1158 if (old_lock
&& (new_feature
!= old_feature
)) {
1159 audit_log_feature_change(i
, old_feature
, new_feature
,
1160 old_lock
, new_lock
, 0);
1164 /* nothing invalid, do the changes */
1165 for (i
= 0; i
<= AUDIT_LAST_FEATURE
; i
++) {
1166 u32 feature
= AUDIT_FEATURE_TO_MASK(i
);
1167 u32 old_feature
, new_feature
, old_lock
, new_lock
;
1169 /* if we are not changing this feature, move along */
1170 if (!(feature
& uaf
->mask
))
1173 old_feature
= af
.features
& feature
;
1174 new_feature
= uaf
->features
& feature
;
1175 old_lock
= af
.lock
& feature
;
1176 new_lock
= (uaf
->lock
| af
.lock
) & feature
;
1178 if (new_feature
!= old_feature
)
1179 audit_log_feature_change(i
, old_feature
, new_feature
,
1180 old_lock
, new_lock
, 1);
1183 af
.features
|= feature
;
1185 af
.features
&= ~feature
;
1186 af
.lock
|= new_lock
;
1192 static int audit_replace(struct pid
*pid
)
1195 struct sk_buff
*skb
;
1197 pvnr
= pid_vnr(pid
);
1198 skb
= audit_make_reply(0, AUDIT_REPLACE
, 0, 0, &pvnr
, sizeof(pvnr
));
1201 return auditd_send_unicast_skb(skb
);
1204 static int audit_receive_msg(struct sk_buff
*skb
, struct nlmsghdr
*nlh
)
1210 struct audit_buffer
*ab
;
1211 u16 msg_type
= nlh
->nlmsg_type
;
1212 struct audit_sig_info
*sig_data
;
1216 err
= audit_netlink_ok(skb
, msg_type
);
1220 seq
= nlh
->nlmsg_seq
;
1221 data
= nlmsg_data(nlh
);
1222 data_len
= nlmsg_len(nlh
);
1226 struct audit_status s
;
1227 memset(&s
, 0, sizeof(s
));
1228 s
.enabled
= audit_enabled
;
1229 s
.failure
= audit_failure
;
1230 /* NOTE: use pid_vnr() so the PID is relative to the current
1232 s
.pid
= auditd_pid_vnr();
1233 s
.rate_limit
= audit_rate_limit
;
1234 s
.backlog_limit
= audit_backlog_limit
;
1235 s
.lost
= atomic_read(&audit_lost
);
1236 s
.backlog
= skb_queue_len(&audit_queue
);
1237 s
.feature_bitmap
= AUDIT_FEATURE_BITMAP_ALL
;
1238 s
.backlog_wait_time
= audit_backlog_wait_time
;
1239 s
.backlog_wait_time_actual
= atomic_read(&audit_backlog_wait_time_actual
);
1240 audit_send_reply(skb
, seq
, AUDIT_GET
, 0, 0, &s
, sizeof(s
));
1244 struct audit_status s
;
1245 memset(&s
, 0, sizeof(s
));
1246 /* guard against past and future API changes */
1247 memcpy(&s
, data
, min_t(size_t, sizeof(s
), data_len
));
1248 if (s
.mask
& AUDIT_STATUS_ENABLED
) {
1249 err
= audit_set_enabled(s
.enabled
);
1253 if (s
.mask
& AUDIT_STATUS_FAILURE
) {
1254 err
= audit_set_failure(s
.failure
);
1258 if (s
.mask
& AUDIT_STATUS_PID
) {
1259 /* NOTE: we are using the vnr PID functions below
1260 * because the s.pid value is relative to the
1261 * namespace of the caller; at present this
1262 * doesn't matter much since you can really only
1263 * run auditd from the initial pid namespace, but
1264 * something to keep in mind if this changes */
1265 pid_t new_pid
= s
.pid
;
1267 struct pid
*req_pid
= task_tgid(current
);
1269 /* Sanity check - PID values must match. Setting
1270 * pid to 0 is how auditd ends auditing. */
1271 if (new_pid
&& (new_pid
!= pid_vnr(req_pid
)))
1274 /* test the auditd connection */
1275 audit_replace(req_pid
);
1277 auditd_pid
= auditd_pid_vnr();
1279 /* replacing a healthy auditd is not allowed */
1281 audit_log_config_change("audit_pid",
1282 new_pid
, auditd_pid
, 0);
1285 /* only current auditd can unregister itself */
1286 if (pid_vnr(req_pid
) != auditd_pid
) {
1287 audit_log_config_change("audit_pid",
1288 new_pid
, auditd_pid
, 0);
1294 /* register a new auditd connection */
1295 err
= auditd_set(req_pid
,
1296 NETLINK_CB(skb
).portid
,
1297 sock_net(NETLINK_CB(skb
).sk
));
1298 if (audit_enabled
!= AUDIT_OFF
)
1299 audit_log_config_change("audit_pid",
1306 /* try to process any backlog */
1307 wake_up_interruptible(&kauditd_wait
);
1309 if (audit_enabled
!= AUDIT_OFF
)
1310 audit_log_config_change("audit_pid",
1314 /* unregister the auditd connection */
1318 if (s
.mask
& AUDIT_STATUS_RATE_LIMIT
) {
1319 err
= audit_set_rate_limit(s
.rate_limit
);
1323 if (s
.mask
& AUDIT_STATUS_BACKLOG_LIMIT
) {
1324 err
= audit_set_backlog_limit(s
.backlog_limit
);
1328 if (s
.mask
& AUDIT_STATUS_BACKLOG_WAIT_TIME
) {
1329 if (sizeof(s
) > (size_t)nlh
->nlmsg_len
)
1331 if (s
.backlog_wait_time
> 10*AUDIT_BACKLOG_WAIT_TIME
)
1333 err
= audit_set_backlog_wait_time(s
.backlog_wait_time
);
1337 if (s
.mask
== AUDIT_STATUS_LOST
) {
1338 u32 lost
= atomic_xchg(&audit_lost
, 0);
1340 audit_log_config_change("lost", 0, lost
, 1);
1343 if (s
.mask
== AUDIT_STATUS_BACKLOG_WAIT_TIME_ACTUAL
) {
1344 u32 actual
= atomic_xchg(&audit_backlog_wait_time_actual
, 0);
1346 audit_log_config_change("backlog_wait_time_actual", 0, actual
, 1);
1351 case AUDIT_GET_FEATURE
:
1352 err
= audit_get_feature(skb
);
1356 case AUDIT_SET_FEATURE
:
1357 if (data_len
< sizeof(struct audit_features
))
1359 err
= audit_set_feature(data
);
1364 case AUDIT_FIRST_USER_MSG
... AUDIT_LAST_USER_MSG
:
1365 case AUDIT_FIRST_USER_MSG2
... AUDIT_LAST_USER_MSG2
:
1366 if (!audit_enabled
&& msg_type
!= AUDIT_USER_AVC
)
1368 /* exit early if there isn't at least one character to print */
1372 err
= audit_filter(msg_type
, AUDIT_FILTER_USER
);
1373 if (err
== 1) { /* match or error */
1377 if (msg_type
== AUDIT_USER_TTY
) {
1378 err
= tty_audit_push();
1382 audit_log_user_recv_msg(&ab
, msg_type
);
1383 if (msg_type
!= AUDIT_USER_TTY
) {
1384 /* ensure NULL termination */
1385 str
[data_len
- 1] = '\0';
1386 audit_log_format(ab
, " msg='%.*s'",
1387 AUDIT_MESSAGE_TEXT_MAX
,
1390 audit_log_format(ab
, " data=");
1391 if (str
[data_len
- 1] == '\0')
1393 audit_log_n_untrustedstring(ab
, str
, data_len
);
1398 case AUDIT_ADD_RULE
:
1399 case AUDIT_DEL_RULE
:
1400 if (data_len
< sizeof(struct audit_rule_data
))
1402 if (audit_enabled
== AUDIT_LOCKED
) {
1403 audit_log_common_recv_msg(audit_context(), &ab
,
1404 AUDIT_CONFIG_CHANGE
);
1405 audit_log_format(ab
, " op=%s audit_enabled=%d res=0",
1406 msg_type
== AUDIT_ADD_RULE
?
1407 "add_rule" : "remove_rule",
1412 err
= audit_rule_change(msg_type
, seq
, data
, data_len
);
1414 case AUDIT_LIST_RULES
:
1415 err
= audit_list_rules_send(skb
, seq
);
1419 audit_log_common_recv_msg(audit_context(), &ab
,
1420 AUDIT_CONFIG_CHANGE
);
1421 audit_log_format(ab
, " op=trim res=1");
1424 case AUDIT_MAKE_EQUIV
: {
1427 size_t msglen
= data_len
;
1431 if (msglen
< 2 * sizeof(u32
))
1433 memcpy(sizes
, bufp
, 2 * sizeof(u32
));
1434 bufp
+= 2 * sizeof(u32
);
1435 msglen
-= 2 * sizeof(u32
);
1436 old
= audit_unpack_string(&bufp
, &msglen
, sizes
[0]);
1441 new = audit_unpack_string(&bufp
, &msglen
, sizes
[1]);
1447 /* OK, here comes... */
1448 err
= audit_tag_tree(old
, new);
1450 audit_log_common_recv_msg(audit_context(), &ab
,
1451 AUDIT_CONFIG_CHANGE
);
1452 audit_log_format(ab
, " op=make_equiv old=");
1453 audit_log_untrustedstring(ab
, old
);
1454 audit_log_format(ab
, " new=");
1455 audit_log_untrustedstring(ab
, new);
1456 audit_log_format(ab
, " res=%d", !err
);
1462 case AUDIT_SIGNAL_INFO
:
1464 if (audit_sig_sid
) {
1465 err
= security_secid_to_secctx(audit_sig_sid
, &ctx
, &len
);
1469 sig_data
= kmalloc(struct_size(sig_data
, ctx
, len
), GFP_KERNEL
);
1472 security_release_secctx(ctx
, len
);
1475 sig_data
->uid
= from_kuid(&init_user_ns
, audit_sig_uid
);
1476 sig_data
->pid
= audit_sig_pid
;
1477 if (audit_sig_sid
) {
1478 memcpy(sig_data
->ctx
, ctx
, len
);
1479 security_release_secctx(ctx
, len
);
1481 audit_send_reply(skb
, seq
, AUDIT_SIGNAL_INFO
, 0, 0,
1482 sig_data
, struct_size(sig_data
, ctx
, len
));
1485 case AUDIT_TTY_GET
: {
1486 struct audit_tty_status s
;
1489 t
= READ_ONCE(current
->signal
->audit_tty
);
1490 s
.enabled
= t
& AUDIT_TTY_ENABLE
;
1491 s
.log_passwd
= !!(t
& AUDIT_TTY_LOG_PASSWD
);
1493 audit_send_reply(skb
, seq
, AUDIT_TTY_GET
, 0, 0, &s
, sizeof(s
));
1496 case AUDIT_TTY_SET
: {
1497 struct audit_tty_status s
, old
;
1498 struct audit_buffer
*ab
;
1501 memset(&s
, 0, sizeof(s
));
1502 /* guard against past and future API changes */
1503 memcpy(&s
, data
, min_t(size_t, sizeof(s
), data_len
));
1504 /* check if new data is valid */
1505 if ((s
.enabled
!= 0 && s
.enabled
!= 1) ||
1506 (s
.log_passwd
!= 0 && s
.log_passwd
!= 1))
1510 t
= READ_ONCE(current
->signal
->audit_tty
);
1512 t
= s
.enabled
| (-s
.log_passwd
& AUDIT_TTY_LOG_PASSWD
);
1513 t
= xchg(¤t
->signal
->audit_tty
, t
);
1515 old
.enabled
= t
& AUDIT_TTY_ENABLE
;
1516 old
.log_passwd
= !!(t
& AUDIT_TTY_LOG_PASSWD
);
1518 audit_log_common_recv_msg(audit_context(), &ab
,
1519 AUDIT_CONFIG_CHANGE
);
1520 audit_log_format(ab
, " op=tty_set old-enabled=%d new-enabled=%d"
1521 " old-log_passwd=%d new-log_passwd=%d res=%d",
1522 old
.enabled
, s
.enabled
, old
.log_passwd
,
1523 s
.log_passwd
, !err
);
1532 return err
< 0 ? err
: 0;
1536 * audit_receive - receive messages from a netlink control socket
1537 * @skb: the message buffer
1539 * Parse the provided skb and deal with any messages that may be present,
1540 * malformed skbs are discarded.
1542 static void audit_receive(struct sk_buff
*skb
)
1544 struct nlmsghdr
*nlh
;
1546 * len MUST be signed for nlmsg_next to be able to dec it below 0
1547 * if the nlmsg_len was not aligned
1552 nlh
= nlmsg_hdr(skb
);
1556 while (nlmsg_ok(nlh
, len
)) {
1557 err
= audit_receive_msg(skb
, nlh
);
1558 /* if err or if this message says it wants a response */
1559 if (err
|| (nlh
->nlmsg_flags
& NLM_F_ACK
))
1560 netlink_ack(skb
, nlh
, err
, NULL
);
1562 nlh
= nlmsg_next(nlh
, &len
);
1566 /* can't block with the ctrl lock, so penalize the sender now */
1567 if (audit_backlog_limit
&&
1568 (skb_queue_len(&audit_queue
) > audit_backlog_limit
)) {
1569 DECLARE_WAITQUEUE(wait
, current
);
1571 /* wake kauditd to try and flush the queue */
1572 wake_up_interruptible(&kauditd_wait
);
1574 add_wait_queue_exclusive(&audit_backlog_wait
, &wait
);
1575 set_current_state(TASK_UNINTERRUPTIBLE
);
1576 schedule_timeout(audit_backlog_wait_time
);
1577 remove_wait_queue(&audit_backlog_wait
, &wait
);
1581 /* Log information about who is connecting to the audit multicast socket */
1582 static void audit_log_multicast(int group
, const char *op
, int err
)
1584 const struct cred
*cred
;
1585 struct tty_struct
*tty
;
1586 char comm
[sizeof(current
->comm
)];
1587 struct audit_buffer
*ab
;
1592 ab
= audit_log_start(audit_context(), GFP_KERNEL
, AUDIT_EVENT_LISTENER
);
1596 cred
= current_cred();
1597 tty
= audit_get_tty();
1598 audit_log_format(ab
, "pid=%u uid=%u auid=%u tty=%s ses=%u",
1599 task_pid_nr(current
),
1600 from_kuid(&init_user_ns
, cred
->uid
),
1601 from_kuid(&init_user_ns
, audit_get_loginuid(current
)),
1602 tty
? tty_name(tty
) : "(none)",
1603 audit_get_sessionid(current
));
1605 audit_log_task_context(ab
); /* subj= */
1606 audit_log_format(ab
, " comm=");
1607 audit_log_untrustedstring(ab
, get_task_comm(comm
, current
));
1608 audit_log_d_path_exe(ab
, current
->mm
); /* exe= */
1609 audit_log_format(ab
, " nl-mcgrp=%d op=%s res=%d", group
, op
, !err
);
1613 /* Run custom bind function on netlink socket group connect or bind requests. */
1614 static int audit_multicast_bind(struct net
*net
, int group
)
1618 if (!capable(CAP_AUDIT_READ
))
1620 audit_log_multicast(group
, "connect", err
);
1624 static void audit_multicast_unbind(struct net
*net
, int group
)
1626 audit_log_multicast(group
, "disconnect", 0);
1629 static int __net_init
audit_net_init(struct net
*net
)
1631 struct netlink_kernel_cfg cfg
= {
1632 .input
= audit_receive
,
1633 .bind
= audit_multicast_bind
,
1634 .unbind
= audit_multicast_unbind
,
1635 .flags
= NL_CFG_F_NONROOT_RECV
,
1636 .groups
= AUDIT_NLGRP_MAX
,
1639 struct audit_net
*aunet
= net_generic(net
, audit_net_id
);
1641 aunet
->sk
= netlink_kernel_create(net
, NETLINK_AUDIT
, &cfg
);
1642 if (aunet
->sk
== NULL
) {
1643 audit_panic("cannot initialize netlink socket in namespace");
1646 /* limit the timeout in case auditd is blocked/stopped */
1647 aunet
->sk
->sk_sndtimeo
= HZ
/ 10;
1652 static void __net_exit
audit_net_exit(struct net
*net
)
1654 struct audit_net
*aunet
= net_generic(net
, audit_net_id
);
1656 /* NOTE: you would think that we would want to check the auditd
1657 * connection and potentially reset it here if it lives in this
1658 * namespace, but since the auditd connection tracking struct holds a
1659 * reference to this namespace (see auditd_set()) we are only ever
1660 * going to get here after that connection has been released */
1662 netlink_kernel_release(aunet
->sk
);
1665 static struct pernet_operations audit_net_ops __net_initdata
= {
1666 .init
= audit_net_init
,
1667 .exit
= audit_net_exit
,
1668 .id
= &audit_net_id
,
1669 .size
= sizeof(struct audit_net
),
1672 /* Initialize audit support at boot time. */
1673 static int __init
audit_init(void)
1677 if (audit_initialized
== AUDIT_DISABLED
)
1680 audit_buffer_cache
= kmem_cache_create("audit_buffer",
1681 sizeof(struct audit_buffer
),
1682 0, SLAB_PANIC
, NULL
);
1684 skb_queue_head_init(&audit_queue
);
1685 skb_queue_head_init(&audit_retry_queue
);
1686 skb_queue_head_init(&audit_hold_queue
);
1688 for (i
= 0; i
< AUDIT_INODE_BUCKETS
; i
++)
1689 INIT_LIST_HEAD(&audit_inode_hash
[i
]);
1691 mutex_init(&audit_cmd_mutex
.lock
);
1692 audit_cmd_mutex
.owner
= NULL
;
1694 pr_info("initializing netlink subsys (%s)\n",
1695 audit_default
? "enabled" : "disabled");
1696 register_pernet_subsys(&audit_net_ops
);
1698 audit_initialized
= AUDIT_INITIALIZED
;
1700 kauditd_task
= kthread_run(kauditd_thread
, NULL
, "kauditd");
1701 if (IS_ERR(kauditd_task
)) {
1702 int err
= PTR_ERR(kauditd_task
);
1703 panic("audit: failed to start the kauditd thread (%d)\n", err
);
1706 audit_log(NULL
, GFP_KERNEL
, AUDIT_KERNEL
,
1707 "state=initialized audit_enabled=%u res=1",
1712 postcore_initcall(audit_init
);
1715 * Process kernel command-line parameter at boot time.
1716 * audit={0|off} or audit={1|on}.
1718 static int __init
audit_enable(char *str
)
1720 if (!strcasecmp(str
, "off") || !strcmp(str
, "0"))
1721 audit_default
= AUDIT_OFF
;
1722 else if (!strcasecmp(str
, "on") || !strcmp(str
, "1"))
1723 audit_default
= AUDIT_ON
;
1725 pr_err("audit: invalid 'audit' parameter value (%s)\n", str
);
1726 audit_default
= AUDIT_ON
;
1729 if (audit_default
== AUDIT_OFF
)
1730 audit_initialized
= AUDIT_DISABLED
;
1731 if (audit_set_enabled(audit_default
))
1732 pr_err("audit: error setting audit state (%d)\n",
1735 pr_info("%s\n", audit_default
?
1736 "enabled (after initialization)" : "disabled (until reboot)");
1740 __setup("audit=", audit_enable
);
1742 /* Process kernel command-line parameter at boot time.
1743 * audit_backlog_limit=<n> */
1744 static int __init
audit_backlog_limit_set(char *str
)
1746 u32 audit_backlog_limit_arg
;
1748 pr_info("audit_backlog_limit: ");
1749 if (kstrtouint(str
, 0, &audit_backlog_limit_arg
)) {
1750 pr_cont("using default of %u, unable to parse %s\n",
1751 audit_backlog_limit
, str
);
1755 audit_backlog_limit
= audit_backlog_limit_arg
;
1756 pr_cont("%d\n", audit_backlog_limit
);
1760 __setup("audit_backlog_limit=", audit_backlog_limit_set
);
1762 static void audit_buffer_free(struct audit_buffer
*ab
)
1768 kmem_cache_free(audit_buffer_cache
, ab
);
1771 static struct audit_buffer
*audit_buffer_alloc(struct audit_context
*ctx
,
1772 gfp_t gfp_mask
, int type
)
1774 struct audit_buffer
*ab
;
1776 ab
= kmem_cache_alloc(audit_buffer_cache
, gfp_mask
);
1780 ab
->skb
= nlmsg_new(AUDIT_BUFSIZ
, gfp_mask
);
1783 if (!nlmsg_put(ab
->skb
, 0, 0, type
, 0, 0))
1787 ab
->gfp_mask
= gfp_mask
;
1792 audit_buffer_free(ab
);
1797 * audit_serial - compute a serial number for the audit record
1799 * Compute a serial number for the audit record. Audit records are
1800 * written to user-space as soon as they are generated, so a complete
1801 * audit record may be written in several pieces. The timestamp of the
1802 * record and this serial number are used by the user-space tools to
1803 * determine which pieces belong to the same audit record. The
1804 * (timestamp,serial) tuple is unique for each syscall and is live from
1805 * syscall entry to syscall exit.
1807 * NOTE: Another possibility is to store the formatted records off the
1808 * audit context (for those records that have a context), and emit them
1809 * all at syscall exit. However, this could delay the reporting of
1810 * significant errors until syscall exit (or never, if the system
1813 unsigned int audit_serial(void)
1815 static atomic_t serial
= ATOMIC_INIT(0);
1817 return atomic_inc_return(&serial
);
1820 static inline void audit_get_stamp(struct audit_context
*ctx
,
1821 struct timespec64
*t
, unsigned int *serial
)
1823 if (!ctx
|| !auditsc_get_stamp(ctx
, t
, serial
)) {
1824 ktime_get_coarse_real_ts64(t
);
1825 *serial
= audit_serial();
1830 * audit_log_start - obtain an audit buffer
1831 * @ctx: audit_context (may be NULL)
1832 * @gfp_mask: type of allocation
1833 * @type: audit message type
1835 * Returns audit_buffer pointer on success or NULL on error.
1837 * Obtain an audit buffer. This routine does locking to obtain the
1838 * audit buffer, but then no locking is required for calls to
1839 * audit_log_*format. If the task (ctx) is a task that is currently in a
1840 * syscall, then the syscall is marked as auditable and an audit record
1841 * will be written at syscall exit. If there is no associated task, then
1842 * task context (ctx) should be NULL.
1844 struct audit_buffer
*audit_log_start(struct audit_context
*ctx
, gfp_t gfp_mask
,
1847 struct audit_buffer
*ab
;
1848 struct timespec64 t
;
1849 unsigned int serial
;
1851 if (audit_initialized
!= AUDIT_INITIALIZED
)
1854 if (unlikely(!audit_filter(type
, AUDIT_FILTER_EXCLUDE
)))
1857 /* NOTE: don't ever fail/sleep on these two conditions:
1858 * 1. auditd generated record - since we need auditd to drain the
1859 * queue; also, when we are checking for auditd, compare PIDs using
1860 * task_tgid_vnr() since auditd_pid is set in audit_receive_msg()
1861 * using a PID anchored in the caller's namespace
1862 * 2. generator holding the audit_cmd_mutex - we don't want to block
1863 * while holding the mutex, although we do penalize the sender
1864 * later in audit_receive() when it is safe to block
1866 if (!(auditd_test_task(current
) || audit_ctl_owner_current())) {
1867 long stime
= audit_backlog_wait_time
;
1869 while (audit_backlog_limit
&&
1870 (skb_queue_len(&audit_queue
) > audit_backlog_limit
)) {
1871 /* wake kauditd to try and flush the queue */
1872 wake_up_interruptible(&kauditd_wait
);
1874 /* sleep if we are allowed and we haven't exhausted our
1875 * backlog wait limit */
1876 if (gfpflags_allow_blocking(gfp_mask
) && (stime
> 0)) {
1879 DECLARE_WAITQUEUE(wait
, current
);
1881 add_wait_queue_exclusive(&audit_backlog_wait
,
1883 set_current_state(TASK_UNINTERRUPTIBLE
);
1884 stime
= schedule_timeout(rtime
);
1885 atomic_add(rtime
- stime
, &audit_backlog_wait_time_actual
);
1886 remove_wait_queue(&audit_backlog_wait
, &wait
);
1888 if (audit_rate_check() && printk_ratelimit())
1889 pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
1890 skb_queue_len(&audit_queue
),
1891 audit_backlog_limit
);
1892 audit_log_lost("backlog limit exceeded");
1898 ab
= audit_buffer_alloc(ctx
, gfp_mask
, type
);
1900 audit_log_lost("out of memory in audit_log_start");
1904 audit_get_stamp(ab
->ctx
, &t
, &serial
);
1905 /* cancel dummy context to enable supporting records */
1908 audit_log_format(ab
, "audit(%llu.%03lu:%u): ",
1909 (unsigned long long)t
.tv_sec
, t
.tv_nsec
/1000000, serial
);
1915 * audit_expand - expand skb in the audit buffer
1917 * @extra: space to add at tail of the skb
1919 * Returns 0 (no space) on failed expansion, or available space if
1922 static inline int audit_expand(struct audit_buffer
*ab
, int extra
)
1924 struct sk_buff
*skb
= ab
->skb
;
1925 int oldtail
= skb_tailroom(skb
);
1926 int ret
= pskb_expand_head(skb
, 0, extra
, ab
->gfp_mask
);
1927 int newtail
= skb_tailroom(skb
);
1930 audit_log_lost("out of memory in audit_expand");
1934 skb
->truesize
+= newtail
- oldtail
;
1939 * Format an audit message into the audit buffer. If there isn't enough
1940 * room in the audit buffer, more room will be allocated and vsnprint
1941 * will be called a second time. Currently, we assume that a printk
1942 * can't format message larger than 1024 bytes, so we don't either.
1944 static void audit_log_vformat(struct audit_buffer
*ab
, const char *fmt
,
1948 struct sk_buff
*skb
;
1956 avail
= skb_tailroom(skb
);
1958 avail
= audit_expand(ab
, AUDIT_BUFSIZ
);
1962 va_copy(args2
, args
);
1963 len
= vsnprintf(skb_tail_pointer(skb
), avail
, fmt
, args
);
1965 /* The printk buffer is 1024 bytes long, so if we get
1966 * here and AUDIT_BUFSIZ is at least 1024, then we can
1967 * log everything that printk could have logged. */
1968 avail
= audit_expand(ab
,
1969 max_t(unsigned, AUDIT_BUFSIZ
, 1+len
-avail
));
1972 len
= vsnprintf(skb_tail_pointer(skb
), avail
, fmt
, args2
);
1983 * audit_log_format - format a message into the audit buffer.
1985 * @fmt: format string
1986 * @...: optional parameters matching @fmt string
1988 * All the work is done in audit_log_vformat.
1990 void audit_log_format(struct audit_buffer
*ab
, const char *fmt
, ...)
1996 va_start(args
, fmt
);
1997 audit_log_vformat(ab
, fmt
, args
);
2002 * audit_log_n_hex - convert a buffer to hex and append it to the audit skb
2003 * @ab: the audit_buffer
2004 * @buf: buffer to convert to hex
2005 * @len: length of @buf to be converted
2007 * No return value; failure to expand is silently ignored.
2009 * This function will take the passed buf and convert it into a string of
2010 * ascii hex digits. The new string is placed onto the skb.
2012 void audit_log_n_hex(struct audit_buffer
*ab
, const unsigned char *buf
,
2015 int i
, avail
, new_len
;
2017 struct sk_buff
*skb
;
2024 avail
= skb_tailroom(skb
);
2026 if (new_len
>= avail
) {
2027 /* Round the buffer request up to the next multiple */
2028 new_len
= AUDIT_BUFSIZ
*(((new_len
-avail
)/AUDIT_BUFSIZ
) + 1);
2029 avail
= audit_expand(ab
, new_len
);
2034 ptr
= skb_tail_pointer(skb
);
2035 for (i
= 0; i
< len
; i
++)
2036 ptr
= hex_byte_pack_upper(ptr
, buf
[i
]);
2038 skb_put(skb
, len
<< 1); /* new string is twice the old string */
2042 * Format a string of no more than slen characters into the audit buffer,
2043 * enclosed in quote marks.
2045 void audit_log_n_string(struct audit_buffer
*ab
, const char *string
,
2050 struct sk_buff
*skb
;
2057 avail
= skb_tailroom(skb
);
2058 new_len
= slen
+ 3; /* enclosing quotes + null terminator */
2059 if (new_len
> avail
) {
2060 avail
= audit_expand(ab
, new_len
);
2064 ptr
= skb_tail_pointer(skb
);
2066 memcpy(ptr
, string
, slen
);
2070 skb_put(skb
, slen
+ 2); /* don't include null terminator */
2074 * audit_string_contains_control - does a string need to be logged in hex
2075 * @string: string to be checked
2076 * @len: max length of the string to check
2078 bool audit_string_contains_control(const char *string
, size_t len
)
2080 const unsigned char *p
;
2081 for (p
= string
; p
< (const unsigned char *)string
+ len
; p
++) {
2082 if (*p
== '"' || *p
< 0x21 || *p
> 0x7e)
2089 * audit_log_n_untrustedstring - log a string that may contain random characters
2091 * @len: length of string (not including trailing null)
2092 * @string: string to be logged
2094 * This code will escape a string that is passed to it if the string
2095 * contains a control character, unprintable character, double quote mark,
2096 * or a space. Unescaped strings will start and end with a double quote mark.
2097 * Strings that are escaped are printed in hex (2 digits per char).
2099 * The caller specifies the number of characters in the string to log, which may
2100 * or may not be the entire string.
2102 void audit_log_n_untrustedstring(struct audit_buffer
*ab
, const char *string
,
2105 if (audit_string_contains_control(string
, len
))
2106 audit_log_n_hex(ab
, string
, len
);
2108 audit_log_n_string(ab
, string
, len
);
2112 * audit_log_untrustedstring - log a string that may contain random characters
2114 * @string: string to be logged
2116 * Same as audit_log_n_untrustedstring(), except that strlen is used to
2117 * determine string length.
2119 void audit_log_untrustedstring(struct audit_buffer
*ab
, const char *string
)
2121 audit_log_n_untrustedstring(ab
, string
, strlen(string
));
2124 /* This is a helper-function to print the escaped d_path */
2125 void audit_log_d_path(struct audit_buffer
*ab
, const char *prefix
,
2126 const struct path
*path
)
2131 audit_log_format(ab
, "%s", prefix
);
2133 /* We will allow 11 spaces for ' (deleted)' to be appended */
2134 pathname
= kmalloc(PATH_MAX
+11, ab
->gfp_mask
);
2136 audit_log_format(ab
, "\"<no_memory>\"");
2139 p
= d_path(path
, pathname
, PATH_MAX
+11);
2140 if (IS_ERR(p
)) { /* Should never happen since we send PATH_MAX */
2141 /* FIXME: can we save some information here? */
2142 audit_log_format(ab
, "\"<too_long>\"");
2144 audit_log_untrustedstring(ab
, p
);
2148 void audit_log_session_info(struct audit_buffer
*ab
)
2150 unsigned int sessionid
= audit_get_sessionid(current
);
2151 uid_t auid
= from_kuid(&init_user_ns
, audit_get_loginuid(current
));
2153 audit_log_format(ab
, "auid=%u ses=%u", auid
, sessionid
);
2156 void audit_log_key(struct audit_buffer
*ab
, char *key
)
2158 audit_log_format(ab
, " key=");
2160 audit_log_untrustedstring(ab
, key
);
2162 audit_log_format(ab
, "(null)");
2165 int audit_log_task_context(struct audit_buffer
*ab
)
2172 security_current_getsecid_subj(&sid
);
2176 error
= security_secid_to_secctx(sid
, &ctx
, &len
);
2178 if (error
!= -EINVAL
)
2183 audit_log_format(ab
, " subj=%s", ctx
);
2184 security_release_secctx(ctx
, len
);
2188 audit_panic("error in audit_log_task_context");
2191 EXPORT_SYMBOL(audit_log_task_context
);
2193 void audit_log_d_path_exe(struct audit_buffer
*ab
,
2194 struct mm_struct
*mm
)
2196 struct file
*exe_file
;
2201 exe_file
= get_mm_exe_file(mm
);
2205 audit_log_d_path(ab
, " exe=", &exe_file
->f_path
);
2209 audit_log_format(ab
, " exe=(null)");
2212 struct tty_struct
*audit_get_tty(void)
2214 struct tty_struct
*tty
= NULL
;
2215 unsigned long flags
;
2217 spin_lock_irqsave(¤t
->sighand
->siglock
, flags
);
2218 if (current
->signal
)
2219 tty
= tty_kref_get(current
->signal
->tty
);
2220 spin_unlock_irqrestore(¤t
->sighand
->siglock
, flags
);
2224 void audit_put_tty(struct tty_struct
*tty
)
2229 void audit_log_task_info(struct audit_buffer
*ab
)
2231 const struct cred
*cred
;
2232 char comm
[sizeof(current
->comm
)];
2233 struct tty_struct
*tty
;
2238 cred
= current_cred();
2239 tty
= audit_get_tty();
2240 audit_log_format(ab
,
2241 " ppid=%d pid=%d auid=%u uid=%u gid=%u"
2242 " euid=%u suid=%u fsuid=%u"
2243 " egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
2244 task_ppid_nr(current
),
2245 task_tgid_nr(current
),
2246 from_kuid(&init_user_ns
, audit_get_loginuid(current
)),
2247 from_kuid(&init_user_ns
, cred
->uid
),
2248 from_kgid(&init_user_ns
, cred
->gid
),
2249 from_kuid(&init_user_ns
, cred
->euid
),
2250 from_kuid(&init_user_ns
, cred
->suid
),
2251 from_kuid(&init_user_ns
, cred
->fsuid
),
2252 from_kgid(&init_user_ns
, cred
->egid
),
2253 from_kgid(&init_user_ns
, cred
->sgid
),
2254 from_kgid(&init_user_ns
, cred
->fsgid
),
2255 tty
? tty_name(tty
) : "(none)",
2256 audit_get_sessionid(current
));
2258 audit_log_format(ab
, " comm=");
2259 audit_log_untrustedstring(ab
, get_task_comm(comm
, current
));
2260 audit_log_d_path_exe(ab
, current
->mm
);
2261 audit_log_task_context(ab
);
2263 EXPORT_SYMBOL(audit_log_task_info
);
2266 * audit_log_path_denied - report a path restriction denial
2267 * @type: audit message type (AUDIT_ANOM_LINK, AUDIT_ANOM_CREAT, etc)
2268 * @operation: specific operation name
2270 void audit_log_path_denied(int type
, const char *operation
)
2272 struct audit_buffer
*ab
;
2274 if (!audit_enabled
|| audit_dummy_context())
2277 /* Generate log with subject, operation, outcome. */
2278 ab
= audit_log_start(audit_context(), GFP_KERNEL
, type
);
2281 audit_log_format(ab
, "op=%s", operation
);
2282 audit_log_task_info(ab
);
2283 audit_log_format(ab
, " res=0");
2287 /* global counter which is incremented every time something logs in */
2288 static atomic_t session_id
= ATOMIC_INIT(0);
2290 static int audit_set_loginuid_perm(kuid_t loginuid
)
2292 /* if we are unset, we don't need privs */
2293 if (!audit_loginuid_set(current
))
2295 /* if AUDIT_FEATURE_LOGINUID_IMMUTABLE means never ever allow a change*/
2296 if (is_audit_feature_set(AUDIT_FEATURE_LOGINUID_IMMUTABLE
))
2298 /* it is set, you need permission */
2299 if (!capable(CAP_AUDIT_CONTROL
))
2301 /* reject if this is not an unset and we don't allow that */
2302 if (is_audit_feature_set(AUDIT_FEATURE_ONLY_UNSET_LOGINUID
)
2303 && uid_valid(loginuid
))
2308 static void audit_log_set_loginuid(kuid_t koldloginuid
, kuid_t kloginuid
,
2309 unsigned int oldsessionid
,
2310 unsigned int sessionid
, int rc
)
2312 struct audit_buffer
*ab
;
2313 uid_t uid
, oldloginuid
, loginuid
;
2314 struct tty_struct
*tty
;
2319 ab
= audit_log_start(audit_context(), GFP_KERNEL
, AUDIT_LOGIN
);
2323 uid
= from_kuid(&init_user_ns
, task_uid(current
));
2324 oldloginuid
= from_kuid(&init_user_ns
, koldloginuid
);
2325 loginuid
= from_kuid(&init_user_ns
, kloginuid
);
2326 tty
= audit_get_tty();
2328 audit_log_format(ab
, "pid=%d uid=%u", task_tgid_nr(current
), uid
);
2329 audit_log_task_context(ab
);
2330 audit_log_format(ab
, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",
2331 oldloginuid
, loginuid
, tty
? tty_name(tty
) : "(none)",
2332 oldsessionid
, sessionid
, !rc
);
2338 * audit_set_loginuid - set current task's loginuid
2339 * @loginuid: loginuid value
2343 * Called (set) from fs/proc/base.c::proc_loginuid_write().
2345 int audit_set_loginuid(kuid_t loginuid
)
2347 unsigned int oldsessionid
, sessionid
= AUDIT_SID_UNSET
;
2351 oldloginuid
= audit_get_loginuid(current
);
2352 oldsessionid
= audit_get_sessionid(current
);
2354 rc
= audit_set_loginuid_perm(loginuid
);
2358 /* are we setting or clearing? */
2359 if (uid_valid(loginuid
)) {
2360 sessionid
= (unsigned int)atomic_inc_return(&session_id
);
2361 if (unlikely(sessionid
== AUDIT_SID_UNSET
))
2362 sessionid
= (unsigned int)atomic_inc_return(&session_id
);
2365 current
->sessionid
= sessionid
;
2366 current
->loginuid
= loginuid
;
2368 audit_log_set_loginuid(oldloginuid
, loginuid
, oldsessionid
, sessionid
, rc
);
2373 * audit_signal_info - record signal info for shutting down audit subsystem
2374 * @sig: signal value
2375 * @t: task being signaled
2377 * If the audit subsystem is being terminated, record the task (pid)
2378 * and uid that is doing that.
2380 int audit_signal_info(int sig
, struct task_struct
*t
)
2382 kuid_t uid
= current_uid(), auid
;
2384 if (auditd_test_task(t
) &&
2385 (sig
== SIGTERM
|| sig
== SIGHUP
||
2386 sig
== SIGUSR1
|| sig
== SIGUSR2
)) {
2387 audit_sig_pid
= task_tgid_nr(current
);
2388 auid
= audit_get_loginuid(current
);
2389 if (uid_valid(auid
))
2390 audit_sig_uid
= auid
;
2392 audit_sig_uid
= uid
;
2393 security_current_getsecid_subj(&audit_sig_sid
);
2396 return audit_signal_info_syscall(t
);
2400 * audit_log_end - end one audit record
2401 * @ab: the audit_buffer
2403 * We can not do a netlink send inside an irq context because it blocks (last
2404 * arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a
2405 * queue and a kthread is scheduled to remove them from the queue outside the
2406 * irq context. May be called in any context.
2408 void audit_log_end(struct audit_buffer
*ab
)
2410 struct sk_buff
*skb
;
2411 struct nlmsghdr
*nlh
;
2416 if (audit_rate_check()) {
2420 /* setup the netlink header, see the comments in
2421 * kauditd_send_multicast_skb() for length quirks */
2422 nlh
= nlmsg_hdr(skb
);
2423 nlh
->nlmsg_len
= skb
->len
- NLMSG_HDRLEN
;
2425 /* queue the netlink packet and poke the kauditd thread */
2426 skb_queue_tail(&audit_queue
, skb
);
2427 wake_up_interruptible(&kauditd_wait
);
2429 audit_log_lost("rate limit exceeded");
2431 audit_buffer_free(ab
);
2435 * audit_log - Log an audit record
2436 * @ctx: audit context
2437 * @gfp_mask: type of allocation
2438 * @type: audit message type
2439 * @fmt: format string to use
2440 * @...: variable parameters matching the format string
2442 * This is a convenience function that calls audit_log_start,
2443 * audit_log_vformat, and audit_log_end. It may be called
2446 void audit_log(struct audit_context
*ctx
, gfp_t gfp_mask
, int type
,
2447 const char *fmt
, ...)
2449 struct audit_buffer
*ab
;
2452 ab
= audit_log_start(ctx
, gfp_mask
, type
);
2454 va_start(args
, fmt
);
2455 audit_log_vformat(ab
, fmt
, args
);
2461 EXPORT_SYMBOL(audit_log_start
);
2462 EXPORT_SYMBOL(audit_log_end
);
2463 EXPORT_SYMBOL(audit_log_format
);
2464 EXPORT_SYMBOL(audit_log
);