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 struct lsmblob audit_sig_lsm
;
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
);
324 unsigned long elapsed
;
327 if (!audit_rate_limit
) return 1;
329 spin_lock_irqsave(&lock
, flags
);
330 if (++messages
< audit_rate_limit
) {
334 elapsed
= now
- last_check
;
341 spin_unlock_irqrestore(&lock
, flags
);
347 * audit_log_lost - conditionally log lost audit message event
348 * @message: the message stating reason for lost audit message
350 * Emit at least 1 message per second, even if audit_rate_check is
352 * Always increment the lost messages counter.
354 void audit_log_lost(const char *message
)
356 static unsigned long last_msg
= 0;
357 static DEFINE_SPINLOCK(lock
);
362 atomic_inc(&audit_lost
);
364 print
= (audit_failure
== AUDIT_FAIL_PANIC
|| !audit_rate_limit
);
367 spin_lock_irqsave(&lock
, flags
);
369 if (now
- last_msg
> HZ
) {
373 spin_unlock_irqrestore(&lock
, flags
);
377 if (printk_ratelimit())
378 pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
379 atomic_read(&audit_lost
),
381 audit_backlog_limit
);
382 audit_panic(message
);
386 static int audit_log_config_change(char *function_name
, u32
new, u32 old
,
389 struct audit_buffer
*ab
;
392 ab
= audit_log_start(audit_context(), GFP_KERNEL
, AUDIT_CONFIG_CHANGE
);
395 audit_log_format(ab
, "op=set %s=%u old=%u ", function_name
, new, old
);
396 audit_log_session_info(ab
);
397 rc
= audit_log_task_context(ab
);
399 allow_changes
= 0; /* Something weird, deny request */
400 audit_log_format(ab
, " res=%d", allow_changes
);
405 static int audit_do_config_change(char *function_name
, u32
*to_change
, u32
new)
407 int allow_changes
, rc
= 0;
408 u32 old
= *to_change
;
410 /* check if we are locked */
411 if (audit_enabled
== AUDIT_LOCKED
)
416 if (audit_enabled
!= AUDIT_OFF
) {
417 rc
= audit_log_config_change(function_name
, new, old
, allow_changes
);
422 /* If we are allowed, make the change */
423 if (allow_changes
== 1)
425 /* Not allowed, update reason */
431 static int audit_set_rate_limit(u32 limit
)
433 return audit_do_config_change("audit_rate_limit", &audit_rate_limit
, limit
);
436 static int audit_set_backlog_limit(u32 limit
)
438 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit
, limit
);
441 static int audit_set_backlog_wait_time(u32 timeout
)
443 return audit_do_config_change("audit_backlog_wait_time",
444 &audit_backlog_wait_time
, timeout
);
447 static int audit_set_enabled(u32 state
)
450 if (state
> AUDIT_LOCKED
)
453 rc
= audit_do_config_change("audit_enabled", &audit_enabled
, state
);
455 audit_ever_enabled
|= !!state
;
460 static int audit_set_failure(u32 state
)
462 if (state
!= AUDIT_FAIL_SILENT
463 && state
!= AUDIT_FAIL_PRINTK
464 && state
!= AUDIT_FAIL_PANIC
)
467 return audit_do_config_change("audit_failure", &audit_failure
, state
);
471 * auditd_conn_free - RCU helper to release an auditd connection struct
475 * Drop any references inside the auditd connection tracking struct and free
478 static void auditd_conn_free(struct rcu_head
*rcu
)
480 struct auditd_connection
*ac
;
482 ac
= container_of(rcu
, struct auditd_connection
, rcu
);
489 * auditd_set - Set/Reset the auditd connection state
491 * @portid: auditd netlink portid
492 * @net: auditd network namespace pointer
495 * This function will obtain and drop network namespace references as
496 * necessary. Returns zero on success, negative values on failure.
498 static int auditd_set(struct pid
*pid
, u32 portid
, struct net
*net
)
501 struct auditd_connection
*ac_old
, *ac_new
;
506 ac_new
= kzalloc(sizeof(*ac_new
), GFP_KERNEL
);
509 ac_new
->pid
= get_pid(pid
);
510 ac_new
->portid
= portid
;
511 ac_new
->net
= get_net(net
);
513 spin_lock_irqsave(&auditd_conn_lock
, flags
);
514 ac_old
= rcu_dereference_protected(auditd_conn
,
515 lockdep_is_held(&auditd_conn_lock
));
516 rcu_assign_pointer(auditd_conn
, ac_new
);
517 spin_unlock_irqrestore(&auditd_conn_lock
, flags
);
520 call_rcu(&ac_old
->rcu
, auditd_conn_free
);
526 * kauditd_printk_skb - Print the audit record to the ring buffer
529 * Whatever the reason, this packet may not make it to the auditd connection
530 * so write it via printk so the information isn't completely lost.
532 static void kauditd_printk_skb(struct sk_buff
*skb
)
534 struct nlmsghdr
*nlh
= nlmsg_hdr(skb
);
535 char *data
= nlmsg_data(nlh
);
537 if (nlh
->nlmsg_type
!= AUDIT_EOE
&& printk_ratelimit())
538 pr_notice("type=%d %s\n", nlh
->nlmsg_type
, data
);
542 * kauditd_rehold_skb - Handle a audit record send failure in the hold queue
546 * This should only be used by the kauditd_thread when it fails to flush the
549 static void kauditd_rehold_skb(struct sk_buff
*skb
)
551 /* put the record back in the queue at the same place */
552 skb_queue_head(&audit_hold_queue
, skb
);
556 * 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
)
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? */
574 if (!audit_default
) {
579 /* if we have room, queue the message */
580 if (!audit_backlog_limit
||
581 skb_queue_len(&audit_hold_queue
) < audit_backlog_limit
) {
582 skb_queue_tail(&audit_hold_queue
, skb
);
586 /* we have no other options - drop the message */
587 audit_log_lost("kauditd hold queue overflow");
592 * kauditd_retry_skb - Queue an audit record, attempt to send again to auditd
596 * Not as serious as kauditd_hold_skb() as we still have a connected auditd,
597 * but for some reason we are having problems sending it audit records so
598 * queue the given record and attempt to resend.
600 static void kauditd_retry_skb(struct sk_buff
*skb
)
602 /* NOTE: because records should only live in the retry queue for a
603 * short period of time, before either being sent or moved to the hold
604 * queue, we don't currently enforce a limit on this queue */
605 skb_queue_tail(&audit_retry_queue
, skb
);
609 * auditd_reset - Disconnect the auditd connection
610 * @ac: auditd connection state
613 * Break the auditd/kauditd connection and move all the queued records into the
614 * hold queue in case auditd reconnects. It is important to note that the @ac
615 * pointer should never be dereferenced inside this function as it may be NULL
616 * or invalid, you can only compare the memory address! If @ac is NULL then
617 * the connection will always be reset.
619 static void auditd_reset(const struct auditd_connection
*ac
)
623 struct auditd_connection
*ac_old
;
625 /* if it isn't already broken, break the connection */
626 spin_lock_irqsave(&auditd_conn_lock
, flags
);
627 ac_old
= rcu_dereference_protected(auditd_conn
,
628 lockdep_is_held(&auditd_conn_lock
));
629 if (ac
&& ac
!= ac_old
) {
630 /* someone already registered a new auditd connection */
631 spin_unlock_irqrestore(&auditd_conn_lock
, flags
);
634 rcu_assign_pointer(auditd_conn
, NULL
);
635 spin_unlock_irqrestore(&auditd_conn_lock
, flags
);
638 call_rcu(&ac_old
->rcu
, auditd_conn_free
);
640 /* flush the retry queue to the hold queue, but don't touch the main
641 * queue since we need to process that normally for multicast */
642 while ((skb
= skb_dequeue(&audit_retry_queue
)))
643 kauditd_hold_skb(skb
);
647 * auditd_send_unicast_skb - Send a record via unicast to auditd
651 * Send a skb to the audit daemon, returns positive/zero values on success and
652 * negative values on failure; in all cases the skb will be consumed by this
653 * function. If the send results in -ECONNREFUSED the connection with auditd
654 * will be reset. This function may sleep so callers should not hold any locks
655 * where this would cause a problem.
657 static int auditd_send_unicast_skb(struct sk_buff
*skb
)
663 struct auditd_connection
*ac
;
665 /* NOTE: we can't call netlink_unicast while in the RCU section so
666 * take a reference to the network namespace and grab local
667 * copies of the namespace, the sock, and the portid; the
668 * namespace and sock aren't going to go away while we hold a
669 * reference and if the portid does become invalid after the RCU
670 * section netlink_unicast() should safely return an error */
673 ac
= rcu_dereference(auditd_conn
);
680 net
= get_net(ac
->net
);
681 sk
= audit_get_sk(net
);
685 rc
= netlink_unicast(sk
, skb
, portid
, 0);
693 if (ac
&& rc
== -ECONNREFUSED
)
699 * kauditd_send_queue - Helper for kauditd_thread to flush skb queues
700 * @sk: the sending sock
701 * @portid: the netlink destination
702 * @queue: the skb queue to process
703 * @retry_limit: limit on number of netlink unicast failures
704 * @skb_hook: per-skb hook for additional processing
705 * @err_hook: hook called if the skb fails the netlink unicast send
708 * Run through the given queue and attempt to send the audit records to auditd,
709 * returns zero on success, negative values on failure. It is up to the caller
710 * to ensure that the @sk is valid for the duration of this function.
713 static int kauditd_send_queue(struct sock
*sk
, u32 portid
,
714 struct sk_buff_head
*queue
,
715 unsigned int retry_limit
,
716 void (*skb_hook
)(struct sk_buff
*skb
),
717 void (*err_hook
)(struct sk_buff
*skb
))
721 static unsigned int failed
= 0;
723 /* NOTE: kauditd_thread takes care of all our locking, we just use
724 * the netlink info passed to us (e.g. sk and portid) */
726 while ((skb
= skb_dequeue(queue
))) {
727 /* call the skb_hook for each skb we touch */
731 /* can we send to anyone via unicast? */
738 /* grab an extra skb reference in case of error */
740 rc
= netlink_unicast(sk
, skb
, portid
, 0);
742 /* fatal failure for our queue flush attempt? */
743 if (++failed
>= retry_limit
||
744 rc
== -ECONNREFUSED
|| rc
== -EPERM
) {
745 /* yes - error processing for the queue */
751 /* keep processing with the skb_hook */
754 /* no - requeue to preserve ordering */
755 skb_queue_head(queue
, skb
);
757 /* it worked - drop the extra reference and continue */
764 return (rc
>= 0 ? 0 : rc
);
768 * kauditd_send_multicast_skb - Send a record to any multicast listeners
772 * Write a multicast message to anyone listening in the initial network
773 * namespace. This function doesn't consume an skb as might be expected since
774 * it has to copy it anyways.
776 static void kauditd_send_multicast_skb(struct sk_buff
*skb
)
778 struct sk_buff
*copy
;
779 struct sock
*sock
= audit_get_sk(&init_net
);
780 struct nlmsghdr
*nlh
;
782 /* NOTE: we are not taking an additional reference for init_net since
783 * we don't have to worry about it going away */
785 if (!netlink_has_listeners(sock
, AUDIT_NLGRP_READLOG
))
789 * The seemingly wasteful skb_copy() rather than bumping the refcount
790 * using skb_get() is necessary because non-standard mods are made to
791 * the skb by the original kaudit unicast socket send routine. The
792 * existing auditd daemon assumes this breakage. Fixing this would
793 * require co-ordinating a change in the established protocol between
794 * the kaudit kernel subsystem and the auditd userspace code. There is
795 * no reason for new multicast clients to continue with this
798 copy
= skb_copy(skb
, GFP_KERNEL
);
801 nlh
= nlmsg_hdr(copy
);
802 nlh
->nlmsg_len
= skb
->len
;
804 nlmsg_multicast(sock
, copy
, 0, AUDIT_NLGRP_READLOG
, GFP_KERNEL
);
808 * kauditd_thread - Worker thread to send audit records to userspace
811 static int kauditd_thread(void *dummy
)
815 struct net
*net
= NULL
;
816 struct sock
*sk
= NULL
;
817 struct auditd_connection
*ac
;
819 #define UNICAST_RETRIES 5
822 while (!kthread_should_stop()) {
823 /* NOTE: see the lock comments in auditd_send_unicast_skb() */
825 ac
= rcu_dereference(auditd_conn
);
830 net
= get_net(ac
->net
);
831 sk
= audit_get_sk(net
);
835 /* attempt to flush the hold queue */
836 rc
= kauditd_send_queue(sk
, portid
,
837 &audit_hold_queue
, UNICAST_RETRIES
,
838 NULL
, kauditd_rehold_skb
);
845 /* attempt to flush the retry queue */
846 rc
= kauditd_send_queue(sk
, portid
,
847 &audit_retry_queue
, UNICAST_RETRIES
,
848 NULL
, kauditd_hold_skb
);
856 /* process the main queue - do the multicast send and attempt
857 * unicast, dump failed record sends to the retry queue; if
858 * sk == NULL due to previous failures we will just do the
859 * multicast send and move the record to the hold queue */
860 rc
= kauditd_send_queue(sk
, portid
, &audit_queue
, 1,
861 kauditd_send_multicast_skb
,
863 kauditd_retry_skb
: kauditd_hold_skb
));
868 /* drop our netns reference, no auditd sends past this line */
874 /* we have processed all the queues so wake everyone */
875 wake_up(&audit_backlog_wait
);
877 /* NOTE: we want to wake up if there is anything on the queue,
878 * regardless of if an auditd is connected, as we need to
879 * do the multicast send and rotate records from the
880 * main queue to the retry/hold queues */
881 wait_event_freezable(kauditd_wait
,
882 (skb_queue_len(&audit_queue
) ? 1 : 0));
888 int audit_send_list_thread(void *_dest
)
890 struct audit_netlink_list
*dest
= _dest
;
892 struct sock
*sk
= audit_get_sk(dest
->net
);
894 /* wait for parent to finish and send an ACK */
898 while ((skb
= __skb_dequeue(&dest
->q
)) != NULL
)
899 netlink_unicast(sk
, skb
, dest
->portid
, 0);
907 struct sk_buff
*audit_make_reply(int seq
, int type
, int done
,
908 int multi
, const void *payload
, int size
)
911 struct nlmsghdr
*nlh
;
913 int flags
= multi
? NLM_F_MULTI
: 0;
914 int t
= done
? NLMSG_DONE
: type
;
916 skb
= nlmsg_new(size
, GFP_KERNEL
);
920 nlh
= nlmsg_put(skb
, 0, seq
, t
, size
, flags
);
923 data
= nlmsg_data(nlh
);
924 memcpy(data
, payload
, size
);
932 static void audit_free_reply(struct audit_reply
*reply
)
937 kfree_skb(reply
->skb
);
943 static int audit_send_reply_thread(void *arg
)
945 struct audit_reply
*reply
= (struct audit_reply
*)arg
;
950 /* Ignore failure. It'll only happen if the sender goes away,
951 because our timeout is set to infinite. */
952 netlink_unicast(audit_get_sk(reply
->net
), reply
->skb
, reply
->portid
, 0);
954 audit_free_reply(reply
);
959 * audit_send_reply - send an audit reply message via netlink
960 * @request_skb: skb of request we are replying to (used to target the reply)
961 * @seq: sequence number
962 * @type: audit message type
963 * @done: done (last) flag
964 * @multi: multi-part message flag
965 * @payload: payload data
966 * @size: payload size
968 * Allocates a skb, builds the netlink message, and sends it to the port id.
970 static void audit_send_reply(struct sk_buff
*request_skb
, int seq
, int type
, int done
,
971 int multi
, const void *payload
, int size
)
973 struct task_struct
*tsk
;
974 struct audit_reply
*reply
;
976 reply
= kzalloc(sizeof(*reply
), GFP_KERNEL
);
980 reply
->skb
= audit_make_reply(seq
, type
, done
, multi
, payload
, size
);
983 reply
->net
= get_net(sock_net(NETLINK_CB(request_skb
).sk
));
984 reply
->portid
= NETLINK_CB(request_skb
).portid
;
986 tsk
= kthread_run(audit_send_reply_thread
, reply
, "audit_send_reply");
993 audit_free_reply(reply
);
997 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
1000 static int audit_netlink_ok(struct sk_buff
*skb
, u16 msg_type
)
1004 /* Only support initial user namespace for now. */
1006 * We return ECONNREFUSED because it tricks userspace into thinking
1007 * that audit was not configured into the kernel. Lots of users
1008 * configure their PAM stack (because that's what the distro does)
1009 * to reject login if unable to send messages to audit. If we return
1010 * ECONNREFUSED the PAM stack thinks the kernel does not have audit
1011 * configured in and will let login proceed. If we return EPERM
1012 * userspace will reject all logins. This should be removed when we
1013 * support non init namespaces!!
1015 if (current_user_ns() != &init_user_ns
)
1016 return -ECONNREFUSED
;
1025 case AUDIT_GET_FEATURE
:
1026 case AUDIT_SET_FEATURE
:
1027 case AUDIT_LIST_RULES
:
1028 case AUDIT_ADD_RULE
:
1029 case AUDIT_DEL_RULE
:
1030 case AUDIT_SIGNAL_INFO
:
1034 case AUDIT_MAKE_EQUIV
:
1035 /* Only support auditd and auditctl in initial pid namespace
1037 if (task_active_pid_ns(current
) != &init_pid_ns
)
1040 if (!netlink_capable(skb
, CAP_AUDIT_CONTROL
))
1044 case AUDIT_FIRST_USER_MSG
... AUDIT_LAST_USER_MSG
:
1045 case AUDIT_FIRST_USER_MSG2
... AUDIT_LAST_USER_MSG2
:
1046 if (!netlink_capable(skb
, CAP_AUDIT_WRITE
))
1049 default: /* bad msg */
1056 static void audit_log_common_recv_msg(struct audit_context
*context
,
1057 struct audit_buffer
**ab
, u16 msg_type
)
1059 uid_t uid
= from_kuid(&init_user_ns
, current_uid());
1060 pid_t pid
= task_tgid_nr(current
);
1062 if (!audit_enabled
&& msg_type
!= AUDIT_USER_AVC
) {
1067 *ab
= audit_log_start(context
, GFP_KERNEL
, msg_type
);
1070 audit_log_format(*ab
, "pid=%d uid=%u ", pid
, uid
);
1071 audit_log_session_info(*ab
);
1072 audit_log_task_context(*ab
);
1075 static inline void audit_log_user_recv_msg(struct audit_buffer
**ab
,
1078 audit_log_common_recv_msg(NULL
, ab
, msg_type
);
1081 int is_audit_feature_set(int i
)
1083 return af
.features
& AUDIT_FEATURE_TO_MASK(i
);
1087 static int audit_get_feature(struct sk_buff
*skb
)
1091 seq
= nlmsg_hdr(skb
)->nlmsg_seq
;
1093 audit_send_reply(skb
, seq
, AUDIT_GET_FEATURE
, 0, 0, &af
, sizeof(af
));
1098 static void audit_log_feature_change(int which
, u32 old_feature
, u32 new_feature
,
1099 u32 old_lock
, u32 new_lock
, int res
)
1101 struct audit_buffer
*ab
;
1103 if (audit_enabled
== AUDIT_OFF
)
1106 ab
= audit_log_start(audit_context(), GFP_KERNEL
, AUDIT_FEATURE_CHANGE
);
1109 audit_log_task_info(ab
);
1110 audit_log_format(ab
, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
1111 audit_feature_names
[which
], !!old_feature
, !!new_feature
,
1112 !!old_lock
, !!new_lock
, res
);
1116 static int audit_set_feature(struct audit_features
*uaf
)
1120 BUILD_BUG_ON(AUDIT_LAST_FEATURE
+ 1 > ARRAY_SIZE(audit_feature_names
));
1122 /* if there is ever a version 2 we should handle that here */
1124 for (i
= 0; i
<= AUDIT_LAST_FEATURE
; i
++) {
1125 u32 feature
= AUDIT_FEATURE_TO_MASK(i
);
1126 u32 old_feature
, new_feature
, old_lock
, new_lock
;
1128 /* if we are not changing this feature, move along */
1129 if (!(feature
& uaf
->mask
))
1132 old_feature
= af
.features
& feature
;
1133 new_feature
= uaf
->features
& feature
;
1134 new_lock
= (uaf
->lock
| af
.lock
) & feature
;
1135 old_lock
= af
.lock
& feature
;
1137 /* are we changing a locked feature? */
1138 if (old_lock
&& (new_feature
!= old_feature
)) {
1139 audit_log_feature_change(i
, old_feature
, new_feature
,
1140 old_lock
, new_lock
, 0);
1144 /* nothing invalid, do the changes */
1145 for (i
= 0; i
<= AUDIT_LAST_FEATURE
; i
++) {
1146 u32 feature
= AUDIT_FEATURE_TO_MASK(i
);
1147 u32 old_feature
, new_feature
, old_lock
, new_lock
;
1149 /* if we are not changing this feature, move along */
1150 if (!(feature
& uaf
->mask
))
1153 old_feature
= af
.features
& feature
;
1154 new_feature
= uaf
->features
& feature
;
1155 old_lock
= af
.lock
& feature
;
1156 new_lock
= (uaf
->lock
| af
.lock
) & feature
;
1158 if (new_feature
!= old_feature
)
1159 audit_log_feature_change(i
, old_feature
, new_feature
,
1160 old_lock
, new_lock
, 1);
1163 af
.features
|= feature
;
1165 af
.features
&= ~feature
;
1166 af
.lock
|= new_lock
;
1172 static int audit_replace(struct pid
*pid
)
1175 struct sk_buff
*skb
;
1177 pvnr
= pid_vnr(pid
);
1178 skb
= audit_make_reply(0, AUDIT_REPLACE
, 0, 0, &pvnr
, sizeof(pvnr
));
1181 return auditd_send_unicast_skb(skb
);
1184 static int audit_receive_msg(struct sk_buff
*skb
, struct nlmsghdr
*nlh
)
1190 struct audit_buffer
*ab
;
1191 u16 msg_type
= nlh
->nlmsg_type
;
1192 struct audit_sig_info
*sig_data
;
1195 struct lsmcontext scaff
; /* scaffolding */
1197 err
= audit_netlink_ok(skb
, msg_type
);
1201 seq
= nlh
->nlmsg_seq
;
1202 data
= nlmsg_data(nlh
);
1203 data_len
= nlmsg_len(nlh
);
1207 struct audit_status s
;
1208 memset(&s
, 0, sizeof(s
));
1209 s
.enabled
= audit_enabled
;
1210 s
.failure
= audit_failure
;
1211 /* NOTE: use pid_vnr() so the PID is relative to the current
1213 s
.pid
= auditd_pid_vnr();
1214 s
.rate_limit
= audit_rate_limit
;
1215 s
.backlog_limit
= audit_backlog_limit
;
1216 s
.lost
= atomic_read(&audit_lost
);
1217 s
.backlog
= skb_queue_len(&audit_queue
);
1218 s
.feature_bitmap
= AUDIT_FEATURE_BITMAP_ALL
;
1219 s
.backlog_wait_time
= audit_backlog_wait_time
;
1220 s
.backlog_wait_time_actual
= atomic_read(&audit_backlog_wait_time_actual
);
1221 audit_send_reply(skb
, seq
, AUDIT_GET
, 0, 0, &s
, sizeof(s
));
1225 struct audit_status s
;
1226 memset(&s
, 0, sizeof(s
));
1227 /* guard against past and future API changes */
1228 memcpy(&s
, data
, min_t(size_t, sizeof(s
), data_len
));
1229 if (s
.mask
& AUDIT_STATUS_ENABLED
) {
1230 err
= audit_set_enabled(s
.enabled
);
1234 if (s
.mask
& AUDIT_STATUS_FAILURE
) {
1235 err
= audit_set_failure(s
.failure
);
1239 if (s
.mask
& AUDIT_STATUS_PID
) {
1240 /* NOTE: we are using the vnr PID functions below
1241 * because the s.pid value is relative to the
1242 * namespace of the caller; at present this
1243 * doesn't matter much since you can really only
1244 * run auditd from the initial pid namespace, but
1245 * something to keep in mind if this changes */
1246 pid_t new_pid
= s
.pid
;
1248 struct pid
*req_pid
= task_tgid(current
);
1250 /* Sanity check - PID values must match. Setting
1251 * pid to 0 is how auditd ends auditing. */
1252 if (new_pid
&& (new_pid
!= pid_vnr(req_pid
)))
1255 /* test the auditd connection */
1256 audit_replace(req_pid
);
1258 auditd_pid
= auditd_pid_vnr();
1260 /* replacing a healthy auditd is not allowed */
1262 audit_log_config_change("audit_pid",
1263 new_pid
, auditd_pid
, 0);
1266 /* only current auditd can unregister itself */
1267 if (pid_vnr(req_pid
) != auditd_pid
) {
1268 audit_log_config_change("audit_pid",
1269 new_pid
, auditd_pid
, 0);
1275 /* register a new auditd connection */
1276 err
= auditd_set(req_pid
,
1277 NETLINK_CB(skb
).portid
,
1278 sock_net(NETLINK_CB(skb
).sk
));
1279 if (audit_enabled
!= AUDIT_OFF
)
1280 audit_log_config_change("audit_pid",
1287 /* try to process any backlog */
1288 wake_up_interruptible(&kauditd_wait
);
1290 if (audit_enabled
!= AUDIT_OFF
)
1291 audit_log_config_change("audit_pid",
1295 /* unregister the auditd connection */
1299 if (s
.mask
& AUDIT_STATUS_RATE_LIMIT
) {
1300 err
= audit_set_rate_limit(s
.rate_limit
);
1304 if (s
.mask
& AUDIT_STATUS_BACKLOG_LIMIT
) {
1305 err
= audit_set_backlog_limit(s
.backlog_limit
);
1309 if (s
.mask
& AUDIT_STATUS_BACKLOG_WAIT_TIME
) {
1310 if (sizeof(s
) > (size_t)nlh
->nlmsg_len
)
1312 if (s
.backlog_wait_time
> 10*AUDIT_BACKLOG_WAIT_TIME
)
1314 err
= audit_set_backlog_wait_time(s
.backlog_wait_time
);
1318 if (s
.mask
== AUDIT_STATUS_LOST
) {
1319 u32 lost
= atomic_xchg(&audit_lost
, 0);
1321 audit_log_config_change("lost", 0, lost
, 1);
1324 if (s
.mask
== AUDIT_STATUS_BACKLOG_WAIT_TIME_ACTUAL
) {
1325 u32 actual
= atomic_xchg(&audit_backlog_wait_time_actual
, 0);
1327 audit_log_config_change("backlog_wait_time_actual", 0, actual
, 1);
1332 case AUDIT_GET_FEATURE
:
1333 err
= audit_get_feature(skb
);
1337 case AUDIT_SET_FEATURE
:
1338 if (data_len
< sizeof(struct audit_features
))
1340 err
= audit_set_feature(data
);
1345 case AUDIT_FIRST_USER_MSG
... AUDIT_LAST_USER_MSG
:
1346 case AUDIT_FIRST_USER_MSG2
... AUDIT_LAST_USER_MSG2
:
1347 if (!audit_enabled
&& msg_type
!= AUDIT_USER_AVC
)
1349 /* exit early if there isn't at least one character to print */
1353 err
= audit_filter(msg_type
, AUDIT_FILTER_USER
);
1354 if (err
== 1) { /* match or error */
1358 if (msg_type
== AUDIT_USER_TTY
) {
1359 err
= tty_audit_push();
1363 audit_log_user_recv_msg(&ab
, msg_type
);
1364 if (msg_type
!= AUDIT_USER_TTY
) {
1365 /* ensure NULL termination */
1366 str
[data_len
- 1] = '\0';
1367 audit_log_format(ab
, " msg='%.*s'",
1368 AUDIT_MESSAGE_TEXT_MAX
,
1371 audit_log_format(ab
, " data=");
1372 if (data_len
> 0 && str
[data_len
- 1] == '\0')
1374 audit_log_n_untrustedstring(ab
, str
, data_len
);
1379 case AUDIT_ADD_RULE
:
1380 case AUDIT_DEL_RULE
:
1381 if (data_len
< sizeof(struct audit_rule_data
))
1383 if (audit_enabled
== AUDIT_LOCKED
) {
1384 audit_log_common_recv_msg(audit_context(), &ab
,
1385 AUDIT_CONFIG_CHANGE
);
1386 audit_log_format(ab
, " op=%s audit_enabled=%d res=0",
1387 msg_type
== AUDIT_ADD_RULE
?
1388 "add_rule" : "remove_rule",
1393 err
= audit_rule_change(msg_type
, seq
, data
, data_len
);
1395 case AUDIT_LIST_RULES
:
1396 err
= audit_list_rules_send(skb
, seq
);
1400 audit_log_common_recv_msg(audit_context(), &ab
,
1401 AUDIT_CONFIG_CHANGE
);
1402 audit_log_format(ab
, " op=trim res=1");
1405 case AUDIT_MAKE_EQUIV
: {
1408 size_t msglen
= data_len
;
1412 if (msglen
< 2 * sizeof(u32
))
1414 memcpy(sizes
, bufp
, 2 * sizeof(u32
));
1415 bufp
+= 2 * sizeof(u32
);
1416 msglen
-= 2 * sizeof(u32
);
1417 old
= audit_unpack_string(&bufp
, &msglen
, sizes
[0]);
1422 new = audit_unpack_string(&bufp
, &msglen
, sizes
[1]);
1428 /* OK, here comes... */
1429 err
= audit_tag_tree(old
, new);
1431 audit_log_common_recv_msg(audit_context(), &ab
,
1432 AUDIT_CONFIG_CHANGE
);
1433 audit_log_format(ab
, " op=make_equiv old=");
1434 audit_log_untrustedstring(ab
, old
);
1435 audit_log_format(ab
, " new=");
1436 audit_log_untrustedstring(ab
, new);
1437 audit_log_format(ab
, " res=%d", !err
);
1443 case AUDIT_SIGNAL_INFO
:
1445 if (lsmblob_is_set(&audit_sig_lsm
)) {
1446 err
= security_secid_to_secctx(&audit_sig_lsm
, &ctx
,
1451 sig_data
= kmalloc(sizeof(*sig_data
) + len
, GFP_KERNEL
);
1453 if (lsmblob_is_set(&audit_sig_lsm
)) {
1454 lsmcontext_init(&scaff
, ctx
, len
, 0);
1455 security_release_secctx(&scaff
);
1459 sig_data
->uid
= from_kuid(&init_user_ns
, audit_sig_uid
);
1460 sig_data
->pid
= audit_sig_pid
;
1461 if (lsmblob_is_set(&audit_sig_lsm
)) {
1462 memcpy(sig_data
->ctx
, ctx
, len
);
1463 lsmcontext_init(&scaff
, ctx
, len
, 0);
1464 security_release_secctx(&scaff
);
1466 audit_send_reply(skb
, seq
, AUDIT_SIGNAL_INFO
, 0, 0,
1467 sig_data
, sizeof(*sig_data
) + len
);
1470 case AUDIT_TTY_GET
: {
1471 struct audit_tty_status s
;
1474 t
= READ_ONCE(current
->signal
->audit_tty
);
1475 s
.enabled
= t
& AUDIT_TTY_ENABLE
;
1476 s
.log_passwd
= !!(t
& AUDIT_TTY_LOG_PASSWD
);
1478 audit_send_reply(skb
, seq
, AUDIT_TTY_GET
, 0, 0, &s
, sizeof(s
));
1481 case AUDIT_TTY_SET
: {
1482 struct audit_tty_status s
, old
;
1483 struct audit_buffer
*ab
;
1486 memset(&s
, 0, sizeof(s
));
1487 /* guard against past and future API changes */
1488 memcpy(&s
, data
, min_t(size_t, sizeof(s
), data_len
));
1489 /* check if new data is valid */
1490 if ((s
.enabled
!= 0 && s
.enabled
!= 1) ||
1491 (s
.log_passwd
!= 0 && s
.log_passwd
!= 1))
1495 t
= READ_ONCE(current
->signal
->audit_tty
);
1497 t
= s
.enabled
| (-s
.log_passwd
& AUDIT_TTY_LOG_PASSWD
);
1498 t
= xchg(¤t
->signal
->audit_tty
, t
);
1500 old
.enabled
= t
& AUDIT_TTY_ENABLE
;
1501 old
.log_passwd
= !!(t
& AUDIT_TTY_LOG_PASSWD
);
1503 audit_log_common_recv_msg(audit_context(), &ab
,
1504 AUDIT_CONFIG_CHANGE
);
1505 audit_log_format(ab
, " op=tty_set old-enabled=%d new-enabled=%d"
1506 " old-log_passwd=%d new-log_passwd=%d res=%d",
1507 old
.enabled
, s
.enabled
, old
.log_passwd
,
1508 s
.log_passwd
, !err
);
1517 return err
< 0 ? err
: 0;
1521 * audit_receive - receive messages from a netlink control socket
1522 * @skb: the message buffer
1524 * Parse the provided skb and deal with any messages that may be present,
1525 * malformed skbs are discarded.
1527 static void audit_receive(struct sk_buff
*skb
)
1529 struct nlmsghdr
*nlh
;
1531 * len MUST be signed for nlmsg_next to be able to dec it below 0
1532 * if the nlmsg_len was not aligned
1537 nlh
= nlmsg_hdr(skb
);
1541 while (nlmsg_ok(nlh
, len
)) {
1542 err
= audit_receive_msg(skb
, nlh
);
1543 /* if err or if this message says it wants a response */
1544 if (err
|| (nlh
->nlmsg_flags
& NLM_F_ACK
))
1545 netlink_ack(skb
, nlh
, err
, NULL
);
1547 nlh
= nlmsg_next(nlh
, &len
);
1552 /* Log information about who is connecting to the audit multicast socket */
1553 static void audit_log_multicast(int group
, const char *op
, int err
)
1555 const struct cred
*cred
;
1556 struct tty_struct
*tty
;
1557 char comm
[sizeof(current
->comm
)];
1558 struct audit_buffer
*ab
;
1563 ab
= audit_log_start(audit_context(), GFP_KERNEL
, AUDIT_EVENT_LISTENER
);
1567 cred
= current_cred();
1568 tty
= audit_get_tty();
1569 audit_log_format(ab
, "pid=%u uid=%u auid=%u tty=%s ses=%u",
1570 task_pid_nr(current
),
1571 from_kuid(&init_user_ns
, cred
->uid
),
1572 from_kuid(&init_user_ns
, audit_get_loginuid(current
)),
1573 tty
? tty_name(tty
) : "(none)",
1574 audit_get_sessionid(current
));
1576 audit_log_task_context(ab
); /* subj= */
1577 audit_log_format(ab
, " comm=");
1578 audit_log_untrustedstring(ab
, get_task_comm(comm
, current
));
1579 audit_log_d_path_exe(ab
, current
->mm
); /* exe= */
1580 audit_log_format(ab
, " nl-mcgrp=%d op=%s res=%d", group
, op
, !err
);
1584 /* Run custom bind function on netlink socket group connect or bind requests. */
1585 static int audit_multicast_bind(struct net
*net
, int group
)
1589 if (!capable(CAP_AUDIT_READ
))
1591 audit_log_multicast(group
, "connect", err
);
1595 static void audit_multicast_unbind(struct net
*net
, int group
)
1597 audit_log_multicast(group
, "disconnect", 0);
1600 static int __net_init
audit_net_init(struct net
*net
)
1602 struct netlink_kernel_cfg cfg
= {
1603 .input
= audit_receive
,
1604 .bind
= audit_multicast_bind
,
1605 .unbind
= audit_multicast_unbind
,
1606 .flags
= NL_CFG_F_NONROOT_RECV
,
1607 .groups
= AUDIT_NLGRP_MAX
,
1610 struct audit_net
*aunet
= net_generic(net
, audit_net_id
);
1612 aunet
->sk
= netlink_kernel_create(net
, NETLINK_AUDIT
, &cfg
);
1613 if (aunet
->sk
== NULL
) {
1614 audit_panic("cannot initialize netlink socket in namespace");
1617 aunet
->sk
->sk_sndtimeo
= MAX_SCHEDULE_TIMEOUT
;
1622 static void __net_exit
audit_net_exit(struct net
*net
)
1624 struct audit_net
*aunet
= net_generic(net
, audit_net_id
);
1626 /* NOTE: you would think that we would want to check the auditd
1627 * connection and potentially reset it here if it lives in this
1628 * namespace, but since the auditd connection tracking struct holds a
1629 * reference to this namespace (see auditd_set()) we are only ever
1630 * going to get here after that connection has been released */
1632 netlink_kernel_release(aunet
->sk
);
1635 static struct pernet_operations audit_net_ops __net_initdata
= {
1636 .init
= audit_net_init
,
1637 .exit
= audit_net_exit
,
1638 .id
= &audit_net_id
,
1639 .size
= sizeof(struct audit_net
),
1642 /* Initialize audit support at boot time. */
1643 static int __init
audit_init(void)
1647 if (audit_initialized
== AUDIT_DISABLED
)
1650 audit_buffer_cache
= kmem_cache_create("audit_buffer",
1651 sizeof(struct audit_buffer
),
1652 0, SLAB_PANIC
, NULL
);
1654 skb_queue_head_init(&audit_queue
);
1655 skb_queue_head_init(&audit_retry_queue
);
1656 skb_queue_head_init(&audit_hold_queue
);
1658 for (i
= 0; i
< AUDIT_INODE_BUCKETS
; i
++)
1659 INIT_LIST_HEAD(&audit_inode_hash
[i
]);
1661 mutex_init(&audit_cmd_mutex
.lock
);
1662 audit_cmd_mutex
.owner
= NULL
;
1664 pr_info("initializing netlink subsys (%s)\n",
1665 audit_default
? "enabled" : "disabled");
1666 register_pernet_subsys(&audit_net_ops
);
1668 audit_initialized
= AUDIT_INITIALIZED
;
1670 kauditd_task
= kthread_run(kauditd_thread
, NULL
, "kauditd");
1671 if (IS_ERR(kauditd_task
)) {
1672 int err
= PTR_ERR(kauditd_task
);
1673 panic("audit: failed to start the kauditd thread (%d)\n", err
);
1676 audit_log(NULL
, GFP_KERNEL
, AUDIT_KERNEL
,
1677 "state=initialized audit_enabled=%u res=1",
1682 postcore_initcall(audit_init
);
1685 * Process kernel command-line parameter at boot time.
1686 * audit={0|off} or audit={1|on}.
1688 static int __init
audit_enable(char *str
)
1690 if (!strcasecmp(str
, "off") || !strcmp(str
, "0"))
1691 audit_default
= AUDIT_OFF
;
1692 else if (!strcasecmp(str
, "on") || !strcmp(str
, "1"))
1693 audit_default
= AUDIT_ON
;
1695 pr_err("audit: invalid 'audit' parameter value (%s)\n", str
);
1696 audit_default
= AUDIT_ON
;
1699 if (audit_default
== AUDIT_OFF
)
1700 audit_initialized
= AUDIT_DISABLED
;
1701 if (audit_set_enabled(audit_default
))
1702 pr_err("audit: error setting audit state (%d)\n",
1705 pr_info("%s\n", audit_default
?
1706 "enabled (after initialization)" : "disabled (until reboot)");
1710 __setup("audit=", audit_enable
);
1712 /* Process kernel command-line parameter at boot time.
1713 * audit_backlog_limit=<n> */
1714 static int __init
audit_backlog_limit_set(char *str
)
1716 u32 audit_backlog_limit_arg
;
1718 pr_info("audit_backlog_limit: ");
1719 if (kstrtouint(str
, 0, &audit_backlog_limit_arg
)) {
1720 pr_cont("using default of %u, unable to parse %s\n",
1721 audit_backlog_limit
, str
);
1725 audit_backlog_limit
= audit_backlog_limit_arg
;
1726 pr_cont("%d\n", audit_backlog_limit
);
1730 __setup("audit_backlog_limit=", audit_backlog_limit_set
);
1732 static void audit_buffer_free(struct audit_buffer
*ab
)
1738 kmem_cache_free(audit_buffer_cache
, ab
);
1741 static struct audit_buffer
*audit_buffer_alloc(struct audit_context
*ctx
,
1742 gfp_t gfp_mask
, int type
)
1744 struct audit_buffer
*ab
;
1746 ab
= kmem_cache_alloc(audit_buffer_cache
, gfp_mask
);
1750 ab
->skb
= nlmsg_new(AUDIT_BUFSIZ
, gfp_mask
);
1753 if (!nlmsg_put(ab
->skb
, 0, 0, type
, 0, 0))
1757 ab
->gfp_mask
= gfp_mask
;
1762 audit_buffer_free(ab
);
1767 * audit_serial - compute a serial number for the audit record
1769 * Compute a serial number for the audit record. Audit records are
1770 * written to user-space as soon as they are generated, so a complete
1771 * audit record may be written in several pieces. The timestamp of the
1772 * record and this serial number are used by the user-space tools to
1773 * determine which pieces belong to the same audit record. The
1774 * (timestamp,serial) tuple is unique for each syscall and is live from
1775 * syscall entry to syscall exit.
1777 * NOTE: Another possibility is to store the formatted records off the
1778 * audit context (for those records that have a context), and emit them
1779 * all at syscall exit. However, this could delay the reporting of
1780 * significant errors until syscall exit (or never, if the system
1783 unsigned int audit_serial(void)
1785 static atomic_t serial
= ATOMIC_INIT(0);
1787 return atomic_inc_return(&serial
);
1790 static inline void audit_get_stamp(struct audit_context
*ctx
,
1791 struct timespec64
*t
, unsigned int *serial
)
1793 if (!ctx
|| !auditsc_get_stamp(ctx
, t
, serial
)) {
1794 ktime_get_coarse_real_ts64(t
);
1795 *serial
= audit_serial();
1800 * audit_log_start - obtain an audit buffer
1801 * @ctx: audit_context (may be NULL)
1802 * @gfp_mask: type of allocation
1803 * @type: audit message type
1805 * Returns audit_buffer pointer on success or NULL on error.
1807 * Obtain an audit buffer. This routine does locking to obtain the
1808 * audit buffer, but then no locking is required for calls to
1809 * audit_log_*format. If the task (ctx) is a task that is currently in a
1810 * syscall, then the syscall is marked as auditable and an audit record
1811 * will be written at syscall exit. If there is no associated task, then
1812 * task context (ctx) should be NULL.
1814 struct audit_buffer
*audit_log_start(struct audit_context
*ctx
, gfp_t gfp_mask
,
1817 struct audit_buffer
*ab
;
1818 struct timespec64 t
;
1819 unsigned int serial
;
1821 if (audit_initialized
!= AUDIT_INITIALIZED
)
1824 if (unlikely(!audit_filter(type
, AUDIT_FILTER_EXCLUDE
)))
1827 /* NOTE: don't ever fail/sleep on these two conditions:
1828 * 1. auditd generated record - since we need auditd to drain the
1829 * queue; also, when we are checking for auditd, compare PIDs using
1830 * task_tgid_vnr() since auditd_pid is set in audit_receive_msg()
1831 * using a PID anchored in the caller's namespace
1832 * 2. generator holding the audit_cmd_mutex - we don't want to block
1833 * while holding the mutex */
1834 if (!(auditd_test_task(current
) || audit_ctl_owner_current())) {
1835 long stime
= audit_backlog_wait_time
;
1837 while (audit_backlog_limit
&&
1838 (skb_queue_len(&audit_queue
) > audit_backlog_limit
)) {
1839 /* wake kauditd to try and flush the queue */
1840 wake_up_interruptible(&kauditd_wait
);
1842 /* sleep if we are allowed and we haven't exhausted our
1843 * backlog wait limit */
1844 if (gfpflags_allow_blocking(gfp_mask
) && (stime
> 0)) {
1847 DECLARE_WAITQUEUE(wait
, current
);
1849 add_wait_queue_exclusive(&audit_backlog_wait
,
1851 set_current_state(TASK_UNINTERRUPTIBLE
);
1852 stime
= schedule_timeout(rtime
);
1853 atomic_add(rtime
- stime
, &audit_backlog_wait_time_actual
);
1854 remove_wait_queue(&audit_backlog_wait
, &wait
);
1856 if (audit_rate_check() && printk_ratelimit())
1857 pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
1858 skb_queue_len(&audit_queue
),
1859 audit_backlog_limit
);
1860 audit_log_lost("backlog limit exceeded");
1866 ab
= audit_buffer_alloc(ctx
, gfp_mask
, type
);
1868 audit_log_lost("out of memory in audit_log_start");
1872 audit_get_stamp(ab
->ctx
, &t
, &serial
);
1873 /* cancel dummy context to enable supporting records */
1876 audit_log_format(ab
, "audit(%llu.%03lu:%u): ",
1877 (unsigned long long)t
.tv_sec
, t
.tv_nsec
/1000000, serial
);
1883 * audit_expand - expand skb in the audit buffer
1885 * @extra: space to add at tail of the skb
1887 * Returns 0 (no space) on failed expansion, or available space if
1890 static inline int audit_expand(struct audit_buffer
*ab
, int extra
)
1892 struct sk_buff
*skb
= ab
->skb
;
1893 int oldtail
= skb_tailroom(skb
);
1894 int ret
= pskb_expand_head(skb
, 0, extra
, ab
->gfp_mask
);
1895 int newtail
= skb_tailroom(skb
);
1898 audit_log_lost("out of memory in audit_expand");
1902 skb
->truesize
+= newtail
- oldtail
;
1907 * Format an audit message into the audit buffer. If there isn't enough
1908 * room in the audit buffer, more room will be allocated and vsnprint
1909 * will be called a second time. Currently, we assume that a printk
1910 * can't format message larger than 1024 bytes, so we don't either.
1912 static void audit_log_vformat(struct audit_buffer
*ab
, const char *fmt
,
1916 struct sk_buff
*skb
;
1924 avail
= skb_tailroom(skb
);
1926 avail
= audit_expand(ab
, AUDIT_BUFSIZ
);
1930 va_copy(args2
, args
);
1931 len
= vsnprintf(skb_tail_pointer(skb
), avail
, fmt
, args
);
1933 /* The printk buffer is 1024 bytes long, so if we get
1934 * here and AUDIT_BUFSIZ is at least 1024, then we can
1935 * log everything that printk could have logged. */
1936 avail
= audit_expand(ab
,
1937 max_t(unsigned, AUDIT_BUFSIZ
, 1+len
-avail
));
1940 len
= vsnprintf(skb_tail_pointer(skb
), avail
, fmt
, args2
);
1951 * audit_log_format - format a message into the audit buffer.
1953 * @fmt: format string
1954 * @...: optional parameters matching @fmt string
1956 * All the work is done in audit_log_vformat.
1958 void audit_log_format(struct audit_buffer
*ab
, const char *fmt
, ...)
1964 va_start(args
, fmt
);
1965 audit_log_vformat(ab
, fmt
, args
);
1970 * audit_log_n_hex - convert a buffer to hex and append it to the audit skb
1971 * @ab: the audit_buffer
1972 * @buf: buffer to convert to hex
1973 * @len: length of @buf to be converted
1975 * No return value; failure to expand is silently ignored.
1977 * This function will take the passed buf and convert it into a string of
1978 * ascii hex digits. The new string is placed onto the skb.
1980 void audit_log_n_hex(struct audit_buffer
*ab
, const unsigned char *buf
,
1983 int i
, avail
, new_len
;
1985 struct sk_buff
*skb
;
1992 avail
= skb_tailroom(skb
);
1994 if (new_len
>= avail
) {
1995 /* Round the buffer request up to the next multiple */
1996 new_len
= AUDIT_BUFSIZ
*(((new_len
-avail
)/AUDIT_BUFSIZ
) + 1);
1997 avail
= audit_expand(ab
, new_len
);
2002 ptr
= skb_tail_pointer(skb
);
2003 for (i
= 0; i
< len
; i
++)
2004 ptr
= hex_byte_pack_upper(ptr
, buf
[i
]);
2006 skb_put(skb
, len
<< 1); /* new string is twice the old string */
2010 * Format a string of no more than slen characters into the audit buffer,
2011 * enclosed in quote marks.
2013 void audit_log_n_string(struct audit_buffer
*ab
, const char *string
,
2018 struct sk_buff
*skb
;
2025 avail
= skb_tailroom(skb
);
2026 new_len
= slen
+ 3; /* enclosing quotes + null terminator */
2027 if (new_len
> avail
) {
2028 avail
= audit_expand(ab
, new_len
);
2032 ptr
= skb_tail_pointer(skb
);
2034 memcpy(ptr
, string
, slen
);
2038 skb_put(skb
, slen
+ 2); /* don't include null terminator */
2042 * audit_string_contains_control - does a string need to be logged in hex
2043 * @string: string to be checked
2044 * @len: max length of the string to check
2046 bool audit_string_contains_control(const char *string
, size_t len
)
2048 const unsigned char *p
;
2049 for (p
= string
; p
< (const unsigned char *)string
+ len
; p
++) {
2050 if (*p
== '"' || *p
< 0x21 || *p
> 0x7e)
2057 * audit_log_n_untrustedstring - log a string that may contain random characters
2059 * @len: length of string (not including trailing null)
2060 * @string: string to be logged
2062 * This code will escape a string that is passed to it if the string
2063 * contains a control character, unprintable character, double quote mark,
2064 * or a space. Unescaped strings will start and end with a double quote mark.
2065 * Strings that are escaped are printed in hex (2 digits per char).
2067 * The caller specifies the number of characters in the string to log, which may
2068 * or may not be the entire string.
2070 void audit_log_n_untrustedstring(struct audit_buffer
*ab
, const char *string
,
2073 if (audit_string_contains_control(string
, len
))
2074 audit_log_n_hex(ab
, string
, len
);
2076 audit_log_n_string(ab
, string
, len
);
2080 * audit_log_untrustedstring - log a string that may contain random characters
2082 * @string: string to be logged
2084 * Same as audit_log_n_untrustedstring(), except that strlen is used to
2085 * determine string length.
2087 void audit_log_untrustedstring(struct audit_buffer
*ab
, const char *string
)
2089 audit_log_n_untrustedstring(ab
, string
, strlen(string
));
2092 /* This is a helper-function to print the escaped d_path */
2093 void audit_log_d_path(struct audit_buffer
*ab
, const char *prefix
,
2094 const struct path
*path
)
2099 audit_log_format(ab
, "%s", prefix
);
2101 /* We will allow 11 spaces for ' (deleted)' to be appended */
2102 pathname
= kmalloc(PATH_MAX
+11, ab
->gfp_mask
);
2104 audit_log_format(ab
, "\"<no_memory>\"");
2107 p
= d_path(path
, pathname
, PATH_MAX
+11);
2108 if (IS_ERR(p
)) { /* Should never happen since we send PATH_MAX */
2109 /* FIXME: can we save some information here? */
2110 audit_log_format(ab
, "\"<too_long>\"");
2112 audit_log_untrustedstring(ab
, p
);
2116 void audit_log_session_info(struct audit_buffer
*ab
)
2118 unsigned int sessionid
= audit_get_sessionid(current
);
2119 uid_t auid
= from_kuid(&init_user_ns
, audit_get_loginuid(current
));
2121 audit_log_format(ab
, "auid=%u ses=%u", auid
, sessionid
);
2124 void audit_log_key(struct audit_buffer
*ab
, char *key
)
2126 audit_log_format(ab
, " key=");
2128 audit_log_untrustedstring(ab
, key
);
2130 audit_log_format(ab
, "(null)");
2133 int audit_log_task_context(struct audit_buffer
*ab
)
2138 struct lsmblob blob
;
2139 struct lsmcontext scaff
; /* scaffolding */
2141 security_task_getsecid(current
, &blob
);
2142 if (!lsmblob_is_set(&blob
))
2145 error
= security_secid_to_secctx(&blob
, &ctx
, &len
);
2147 if (error
!= -EINVAL
)
2152 audit_log_format(ab
, " subj=%s", ctx
);
2153 lsmcontext_init(&scaff
, ctx
, len
, 0);
2154 security_release_secctx(&scaff
);
2158 audit_panic("error in audit_log_task_context");
2161 EXPORT_SYMBOL(audit_log_task_context
);
2163 void audit_log_d_path_exe(struct audit_buffer
*ab
,
2164 struct mm_struct
*mm
)
2166 struct file
*exe_file
;
2171 exe_file
= get_mm_exe_file(mm
);
2175 audit_log_d_path(ab
, " exe=", &exe_file
->f_path
);
2179 audit_log_format(ab
, " exe=(null)");
2182 struct tty_struct
*audit_get_tty(void)
2184 struct tty_struct
*tty
= NULL
;
2185 unsigned long flags
;
2187 spin_lock_irqsave(¤t
->sighand
->siglock
, flags
);
2188 if (current
->signal
)
2189 tty
= tty_kref_get(current
->signal
->tty
);
2190 spin_unlock_irqrestore(¤t
->sighand
->siglock
, flags
);
2194 void audit_put_tty(struct tty_struct
*tty
)
2199 void audit_log_task_info(struct audit_buffer
*ab
)
2201 const struct cred
*cred
;
2202 char comm
[sizeof(current
->comm
)];
2203 struct tty_struct
*tty
;
2208 cred
= current_cred();
2209 tty
= audit_get_tty();
2210 audit_log_format(ab
,
2211 " ppid=%d pid=%d auid=%u uid=%u gid=%u"
2212 " euid=%u suid=%u fsuid=%u"
2213 " egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
2214 task_ppid_nr(current
),
2215 task_tgid_nr(current
),
2216 from_kuid(&init_user_ns
, audit_get_loginuid(current
)),
2217 from_kuid(&init_user_ns
, cred
->uid
),
2218 from_kgid(&init_user_ns
, cred
->gid
),
2219 from_kuid(&init_user_ns
, cred
->euid
),
2220 from_kuid(&init_user_ns
, cred
->suid
),
2221 from_kuid(&init_user_ns
, cred
->fsuid
),
2222 from_kgid(&init_user_ns
, cred
->egid
),
2223 from_kgid(&init_user_ns
, cred
->sgid
),
2224 from_kgid(&init_user_ns
, cred
->fsgid
),
2225 tty
? tty_name(tty
) : "(none)",
2226 audit_get_sessionid(current
));
2228 audit_log_format(ab
, " comm=");
2229 audit_log_untrustedstring(ab
, get_task_comm(comm
, current
));
2230 audit_log_d_path_exe(ab
, current
->mm
);
2231 audit_log_task_context(ab
);
2233 EXPORT_SYMBOL(audit_log_task_info
);
2236 * audit_log_path_denied - report a path restriction denial
2237 * @type: audit message type (AUDIT_ANOM_LINK, AUDIT_ANOM_CREAT, etc)
2238 * @operation: specific operation name
2240 void audit_log_path_denied(int type
, const char *operation
)
2242 struct audit_buffer
*ab
;
2244 if (!audit_enabled
|| audit_dummy_context())
2247 /* Generate log with subject, operation, outcome. */
2248 ab
= audit_log_start(audit_context(), GFP_KERNEL
, type
);
2251 audit_log_format(ab
, "op=%s", operation
);
2252 audit_log_task_info(ab
);
2253 audit_log_format(ab
, " res=0");
2257 /* global counter which is incremented every time something logs in */
2258 static atomic_t session_id
= ATOMIC_INIT(0);
2260 static int audit_set_loginuid_perm(kuid_t loginuid
)
2262 /* if we are unset, we don't need privs */
2263 if (!audit_loginuid_set(current
))
2265 /* if AUDIT_FEATURE_LOGINUID_IMMUTABLE means never ever allow a change*/
2266 if (is_audit_feature_set(AUDIT_FEATURE_LOGINUID_IMMUTABLE
))
2268 /* it is set, you need permission */
2269 if (!capable(CAP_AUDIT_CONTROL
))
2271 /* reject if this is not an unset and we don't allow that */
2272 if (is_audit_feature_set(AUDIT_FEATURE_ONLY_UNSET_LOGINUID
)
2273 && uid_valid(loginuid
))
2278 static void audit_log_set_loginuid(kuid_t koldloginuid
, kuid_t kloginuid
,
2279 unsigned int oldsessionid
,
2280 unsigned int sessionid
, int rc
)
2282 struct audit_buffer
*ab
;
2283 uid_t uid
, oldloginuid
, loginuid
;
2284 struct tty_struct
*tty
;
2289 ab
= audit_log_start(audit_context(), GFP_KERNEL
, AUDIT_LOGIN
);
2293 uid
= from_kuid(&init_user_ns
, task_uid(current
));
2294 oldloginuid
= from_kuid(&init_user_ns
, koldloginuid
);
2295 loginuid
= from_kuid(&init_user_ns
, kloginuid
),
2296 tty
= audit_get_tty();
2298 audit_log_format(ab
, "pid=%d uid=%u", task_tgid_nr(current
), uid
);
2299 audit_log_task_context(ab
);
2300 audit_log_format(ab
, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",
2301 oldloginuid
, loginuid
, tty
? tty_name(tty
) : "(none)",
2302 oldsessionid
, sessionid
, !rc
);
2308 * audit_set_loginuid - set current task's loginuid
2309 * @loginuid: loginuid value
2313 * Called (set) from fs/proc/base.c::proc_loginuid_write().
2315 int audit_set_loginuid(kuid_t loginuid
)
2317 unsigned int oldsessionid
, sessionid
= AUDIT_SID_UNSET
;
2321 oldloginuid
= audit_get_loginuid(current
);
2322 oldsessionid
= audit_get_sessionid(current
);
2324 rc
= audit_set_loginuid_perm(loginuid
);
2328 /* are we setting or clearing? */
2329 if (uid_valid(loginuid
)) {
2330 sessionid
= (unsigned int)atomic_inc_return(&session_id
);
2331 if (unlikely(sessionid
== AUDIT_SID_UNSET
))
2332 sessionid
= (unsigned int)atomic_inc_return(&session_id
);
2335 current
->sessionid
= sessionid
;
2336 current
->loginuid
= loginuid
;
2338 audit_log_set_loginuid(oldloginuid
, loginuid
, oldsessionid
, sessionid
, rc
);
2343 * audit_signal_info - record signal info for shutting down audit subsystem
2344 * @sig: signal value
2345 * @t: task being signaled
2347 * If the audit subsystem is being terminated, record the task (pid)
2348 * and uid that is doing that.
2350 int audit_signal_info(int sig
, struct task_struct
*t
)
2352 kuid_t uid
= current_uid(), auid
;
2354 if (auditd_test_task(t
) &&
2355 (sig
== SIGTERM
|| sig
== SIGHUP
||
2356 sig
== SIGUSR1
|| sig
== SIGUSR2
)) {
2357 audit_sig_pid
= task_tgid_nr(current
);
2358 auid
= audit_get_loginuid(current
);
2359 if (uid_valid(auid
))
2360 audit_sig_uid
= auid
;
2362 audit_sig_uid
= uid
;
2363 security_task_getsecid(current
, &audit_sig_lsm
);
2366 return audit_signal_info_syscall(t
);
2370 * audit_log_end - end one audit record
2371 * @ab: the audit_buffer
2373 * We can not do a netlink send inside an irq context because it blocks (last
2374 * arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a
2375 * queue and a tasklet is scheduled to remove them from the queue outside the
2376 * irq context. May be called in any context.
2378 void audit_log_end(struct audit_buffer
*ab
)
2380 struct sk_buff
*skb
;
2381 struct nlmsghdr
*nlh
;
2386 if (audit_rate_check()) {
2390 /* setup the netlink header, see the comments in
2391 * kauditd_send_multicast_skb() for length quirks */
2392 nlh
= nlmsg_hdr(skb
);
2393 nlh
->nlmsg_len
= skb
->len
- NLMSG_HDRLEN
;
2395 /* queue the netlink packet and poke the kauditd thread */
2396 skb_queue_tail(&audit_queue
, skb
);
2397 wake_up_interruptible(&kauditd_wait
);
2399 audit_log_lost("rate limit exceeded");
2401 audit_buffer_free(ab
);
2405 * audit_log - Log an audit record
2406 * @ctx: audit context
2407 * @gfp_mask: type of allocation
2408 * @type: audit message type
2409 * @fmt: format string to use
2410 * @...: variable parameters matching the format string
2412 * This is a convenience function that calls audit_log_start,
2413 * audit_log_vformat, and audit_log_end. It may be called
2416 void audit_log(struct audit_context
*ctx
, gfp_t gfp_mask
, int type
,
2417 const char *fmt
, ...)
2419 struct audit_buffer
*ab
;
2422 ab
= audit_log_start(ctx
, gfp_mask
, type
);
2424 va_start(args
, fmt
);
2425 audit_log_vformat(ab
, fmt
, args
);
2431 EXPORT_SYMBOL(audit_log_start
);
2432 EXPORT_SYMBOL(audit_log_end
);
2433 EXPORT_SYMBOL(audit_log_format
);
2434 EXPORT_SYMBOL(audit_log
);