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;
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);
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_print_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;
1196 err = audit_netlink_ok(skb, msg_type);
1200 seq = nlh->nlmsg_seq;
1201 data = nlmsg_data(nlh);
1202 data_len = nlmsg_len(nlh);
1206 struct audit_status s;
1207 memset(&s, 0, sizeof(s));
1208 s.enabled = audit_enabled;
1209 s.failure = audit_failure;
1210 /* NOTE: use pid_vnr() so the PID is relative to the current
1212 s.pid = auditd_pid_vnr();
1213 s.rate_limit = audit_rate_limit;
1214 s.backlog_limit = audit_backlog_limit;
1215 s.lost = atomic_read(&audit_lost);
1216 s.backlog = skb_queue_len(&audit_queue);
1217 s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL;
1218 s.backlog_wait_time = audit_backlog_wait_time;
1219 s.backlog_wait_time_actual = atomic_read(&audit_backlog_wait_time_actual);
1220 audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
1224 struct audit_status s;
1225 memset(&s, 0, sizeof(s));
1226 /* guard against past and future API changes */
1227 memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
1228 if (s.mask & AUDIT_STATUS_ENABLED) {
1229 err = audit_set_enabled(s.enabled);
1233 if (s.mask & AUDIT_STATUS_FAILURE) {
1234 err = audit_set_failure(s.failure);
1238 if (s.mask & AUDIT_STATUS_PID) {
1239 /* NOTE: we are using the vnr PID functions below
1240 * because the s.pid value is relative to the
1241 * namespace of the caller; at present this
1242 * doesn't matter much since you can really only
1243 * run auditd from the initial pid namespace, but
1244 * something to keep in mind if this changes */
1245 pid_t new_pid = s.pid;
1247 struct pid *req_pid = task_tgid(current);
1249 /* Sanity check - PID values must match. Setting
1250 * pid to 0 is how auditd ends auditing. */
1251 if (new_pid && (new_pid != pid_vnr(req_pid)))
1254 /* test the auditd connection */
1255 audit_replace(req_pid);
1257 auditd_pid = auditd_pid_vnr();
1259 /* replacing a healthy auditd is not allowed */
1261 audit_log_config_change("audit_pid",
1262 new_pid, auditd_pid, 0);
1265 /* only current auditd can unregister itself */
1266 if (pid_vnr(req_pid) != auditd_pid) {
1267 audit_log_config_change("audit_pid",
1268 new_pid, auditd_pid, 0);
1274 /* register a new auditd connection */
1275 err = auditd_set(req_pid,
1276 NETLINK_CB(skb).portid,
1277 sock_net(NETLINK_CB(skb).sk));
1278 if (audit_enabled != AUDIT_OFF)
1279 audit_log_config_change("audit_pid",
1286 /* try to process any backlog */
1287 wake_up_interruptible(&kauditd_wait);
1289 if (audit_enabled != AUDIT_OFF)
1290 audit_log_config_change("audit_pid",
1294 /* unregister the auditd connection */
1298 if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
1299 err = audit_set_rate_limit(s.rate_limit);
1303 if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
1304 err = audit_set_backlog_limit(s.backlog_limit);
1308 if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
1309 if (sizeof(s) > (size_t)nlh->nlmsg_len)
1311 if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
1313 err = audit_set_backlog_wait_time(s.backlog_wait_time);
1317 if (s.mask == AUDIT_STATUS_LOST) {
1318 u32 lost = atomic_xchg(&audit_lost, 0);
1320 audit_log_config_change("lost", 0, lost, 1);
1323 if (s.mask == AUDIT_STATUS_BACKLOG_WAIT_TIME_ACTUAL) {
1324 u32 actual = atomic_xchg(&audit_backlog_wait_time_actual, 0);
1326 audit_log_config_change("backlog_wait_time_actual", 0, actual, 1);
1331 case AUDIT_GET_FEATURE:
1332 err = audit_get_feature(skb);
1336 case AUDIT_SET_FEATURE:
1337 if (data_len < sizeof(struct audit_features))
1339 err = audit_set_feature(data);
1344 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1345 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1346 if (!audit_enabled && msg_type != AUDIT_USER_AVC)
1348 /* exit early if there isn't at least one character to print */
1352 err = audit_filter(msg_type, AUDIT_FILTER_USER);
1353 if (err == 1) { /* match or error */
1357 if (msg_type == AUDIT_USER_TTY) {
1358 err = tty_audit_push();
1362 audit_log_user_recv_msg(&ab, msg_type);
1363 if (msg_type != AUDIT_USER_TTY) {
1364 /* ensure NULL termination */
1365 str[data_len - 1] = '\0';
1366 audit_log_format(ab, " msg='%.*s'",
1367 AUDIT_MESSAGE_TEXT_MAX,
1370 audit_log_format(ab, " data=");
1371 if (data_len > 0 && str[data_len - 1] == '\0')
1373 audit_log_n_untrustedstring(ab, str, data_len);
1378 case AUDIT_ADD_RULE:
1379 case AUDIT_DEL_RULE:
1380 if (data_len < sizeof(struct audit_rule_data))
1382 if (audit_enabled == AUDIT_LOCKED) {
1383 audit_log_common_recv_msg(audit_context(), &ab,
1384 AUDIT_CONFIG_CHANGE);
1385 audit_log_format(ab, " op=%s audit_enabled=%d res=0",
1386 msg_type == AUDIT_ADD_RULE ?
1387 "add_rule" : "remove_rule",
1392 err = audit_rule_change(msg_type, seq, data, data_len);
1394 case AUDIT_LIST_RULES:
1395 err = audit_list_rules_send(skb, seq);
1399 audit_log_common_recv_msg(audit_context(), &ab,
1400 AUDIT_CONFIG_CHANGE);
1401 audit_log_format(ab, " op=trim res=1");
1404 case AUDIT_MAKE_EQUIV: {
1407 size_t msglen = data_len;
1411 if (msglen < 2 * sizeof(u32))
1413 memcpy(sizes, bufp, 2 * sizeof(u32));
1414 bufp += 2 * sizeof(u32);
1415 msglen -= 2 * sizeof(u32);
1416 old = audit_unpack_string(&bufp, &msglen, sizes[0]);
1421 new = audit_unpack_string(&bufp, &msglen, sizes[1]);
1427 /* OK, here comes... */
1428 err = audit_tag_tree(old, new);
1430 audit_log_common_recv_msg(audit_context(), &ab,
1431 AUDIT_CONFIG_CHANGE);
1432 audit_log_format(ab, " op=make_equiv old=");
1433 audit_log_untrustedstring(ab, old);
1434 audit_log_format(ab, " new=");
1435 audit_log_untrustedstring(ab, new);
1436 audit_log_format(ab, " res=%d", !err);
1442 case AUDIT_SIGNAL_INFO:
1444 if (audit_sig_sid) {
1445 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
1449 sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
1452 security_release_secctx(ctx, len);
1455 sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
1456 sig_data->pid = audit_sig_pid;
1457 if (audit_sig_sid) {
1458 memcpy(sig_data->ctx, ctx, len);
1459 security_release_secctx(ctx, len);
1461 audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
1462 sig_data, sizeof(*sig_data) + len);
1465 case AUDIT_TTY_GET: {
1466 struct audit_tty_status s;
1469 t = READ_ONCE(current->signal->audit_tty);
1470 s.enabled = t & AUDIT_TTY_ENABLE;
1471 s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1473 audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
1476 case AUDIT_TTY_SET: {
1477 struct audit_tty_status s, old;
1478 struct audit_buffer *ab;
1481 memset(&s, 0, sizeof(s));
1482 /* guard against past and future API changes */
1483 memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
1484 /* check if new data is valid */
1485 if ((s.enabled != 0 && s.enabled != 1) ||
1486 (s.log_passwd != 0 && s.log_passwd != 1))
1490 t = READ_ONCE(current->signal->audit_tty);
1492 t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD);
1493 t = xchg(¤t->signal->audit_tty, t);
1495 old.enabled = t & AUDIT_TTY_ENABLE;
1496 old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1498 audit_log_common_recv_msg(audit_context(), &ab,
1499 AUDIT_CONFIG_CHANGE);
1500 audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
1501 " old-log_passwd=%d new-log_passwd=%d res=%d",
1502 old.enabled, s.enabled, old.log_passwd,
1503 s.log_passwd, !err);
1512 return err < 0 ? err : 0;
1516 * audit_receive - receive messages from a netlink control socket
1517 * @skb: the message buffer
1519 * Parse the provided skb and deal with any messages that may be present,
1520 * malformed skbs are discarded.
1522 static void audit_receive(struct sk_buff *skb)
1524 struct nlmsghdr *nlh;
1526 * len MUST be signed for nlmsg_next to be able to dec it below 0
1527 * if the nlmsg_len was not aligned
1532 nlh = nlmsg_hdr(skb);
1536 while (nlmsg_ok(nlh, len)) {
1537 err = audit_receive_msg(skb, nlh);
1538 /* if err or if this message says it wants a response */
1539 if (err || (nlh->nlmsg_flags & NLM_F_ACK))
1540 netlink_ack(skb, nlh, err, NULL);
1542 nlh = nlmsg_next(nlh, &len);
1547 /* Log information about who is connecting to the audit multicast socket */
1548 static void audit_log_multicast(int group, const char *op, int err)
1550 const struct cred *cred;
1551 struct tty_struct *tty;
1552 char comm[sizeof(current->comm)];
1553 struct audit_buffer *ab;
1558 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_EVENT_LISTENER);
1562 cred = current_cred();
1563 tty = audit_get_tty();
1564 audit_log_format(ab, "pid=%u uid=%u auid=%u tty=%s ses=%u",
1565 task_pid_nr(current),
1566 from_kuid(&init_user_ns, cred->uid),
1567 from_kuid(&init_user_ns, audit_get_loginuid(current)),
1568 tty ? tty_name(tty) : "(none)",
1569 audit_get_sessionid(current));
1571 audit_log_task_context(ab); /* subj= */
1572 audit_log_format(ab, " comm=");
1573 audit_log_untrustedstring(ab, get_task_comm(comm, current));
1574 audit_log_d_path_exe(ab, current->mm); /* exe= */
1575 audit_log_format(ab, " nl-mcgrp=%d op=%s res=%d", group, op, !err);
1579 /* Run custom bind function on netlink socket group connect or bind requests. */
1580 static int audit_multicast_bind(struct net *net, int group)
1584 if (!capable(CAP_AUDIT_READ))
1586 audit_log_multicast(group, "connect", err);
1590 static void audit_multicast_unbind(struct net *net, int group)
1592 audit_log_multicast(group, "disconnect", 0);
1595 static int __net_init audit_net_init(struct net *net)
1597 struct netlink_kernel_cfg cfg = {
1598 .input = audit_receive,
1599 .bind = audit_multicast_bind,
1600 .unbind = audit_multicast_unbind,
1601 .flags = NL_CFG_F_NONROOT_RECV,
1602 .groups = AUDIT_NLGRP_MAX,
1605 struct audit_net *aunet = net_generic(net, audit_net_id);
1607 aunet->sk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
1608 if (aunet->sk == NULL) {
1609 audit_panic("cannot initialize netlink socket in namespace");
1612 aunet->sk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
1617 static void __net_exit audit_net_exit(struct net *net)
1619 struct audit_net *aunet = net_generic(net, audit_net_id);
1621 /* NOTE: you would think that we would want to check the auditd
1622 * connection and potentially reset it here if it lives in this
1623 * namespace, but since the auditd connection tracking struct holds a
1624 * reference to this namespace (see auditd_set()) we are only ever
1625 * going to get here after that connection has been released */
1627 netlink_kernel_release(aunet->sk);
1630 static struct pernet_operations audit_net_ops __net_initdata = {
1631 .init = audit_net_init,
1632 .exit = audit_net_exit,
1633 .id = &audit_net_id,
1634 .size = sizeof(struct audit_net),
1637 /* Initialize audit support at boot time. */
1638 static int __init audit_init(void)
1642 if (audit_initialized == AUDIT_DISABLED)
1645 audit_buffer_cache = kmem_cache_create("audit_buffer",
1646 sizeof(struct audit_buffer),
1647 0, SLAB_PANIC, NULL);
1649 skb_queue_head_init(&audit_queue);
1650 skb_queue_head_init(&audit_retry_queue);
1651 skb_queue_head_init(&audit_hold_queue);
1653 for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
1654 INIT_LIST_HEAD(&audit_inode_hash[i]);
1656 mutex_init(&audit_cmd_mutex.lock);
1657 audit_cmd_mutex.owner = NULL;
1659 pr_info("initializing netlink subsys (%s)\n",
1660 audit_default ? "enabled" : "disabled");
1661 register_pernet_subsys(&audit_net_ops);
1663 audit_initialized = AUDIT_INITIALIZED;
1665 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
1666 if (IS_ERR(kauditd_task)) {
1667 int err = PTR_ERR(kauditd_task);
1668 panic("audit: failed to start the kauditd thread (%d)\n", err);
1671 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL,
1672 "state=initialized audit_enabled=%u res=1",
1677 postcore_initcall(audit_init);
1680 * Process kernel command-line parameter at boot time.
1681 * audit={0|off} or audit={1|on}.
1683 static int __init audit_enable(char *str)
1685 if (!strcasecmp(str, "off") || !strcmp(str, "0"))
1686 audit_default = AUDIT_OFF;
1687 else if (!strcasecmp(str, "on") || !strcmp(str, "1"))
1688 audit_default = AUDIT_ON;
1690 pr_err("audit: invalid 'audit' parameter value (%s)\n", str);
1691 audit_default = AUDIT_ON;
1694 if (audit_default == AUDIT_OFF)
1695 audit_initialized = AUDIT_DISABLED;
1696 if (audit_set_enabled(audit_default))
1697 pr_err("audit: error setting audit state (%d)\n",
1700 pr_info("%s\n", audit_default ?
1701 "enabled (after initialization)" : "disabled (until reboot)");
1705 __setup("audit=", audit_enable);
1707 /* Process kernel command-line parameter at boot time.
1708 * audit_backlog_limit=<n> */
1709 static int __init audit_backlog_limit_set(char *str)
1711 u32 audit_backlog_limit_arg;
1713 pr_info("audit_backlog_limit: ");
1714 if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
1715 pr_cont("using default of %u, unable to parse %s\n",
1716 audit_backlog_limit, str);
1720 audit_backlog_limit = audit_backlog_limit_arg;
1721 pr_cont("%d\n", audit_backlog_limit);
1725 __setup("audit_backlog_limit=", audit_backlog_limit_set);
1727 static void audit_buffer_free(struct audit_buffer *ab)
1733 kmem_cache_free(audit_buffer_cache, ab);
1736 static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx,
1737 gfp_t gfp_mask, int type)
1739 struct audit_buffer *ab;
1741 ab = kmem_cache_alloc(audit_buffer_cache, gfp_mask);
1745 ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
1748 if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0))
1752 ab->gfp_mask = gfp_mask;
1757 audit_buffer_free(ab);
1762 * audit_serial - compute a serial number for the audit record
1764 * Compute a serial number for the audit record. Audit records are
1765 * written to user-space as soon as they are generated, so a complete
1766 * audit record may be written in several pieces. The timestamp of the
1767 * record and this serial number are used by the user-space tools to
1768 * determine which pieces belong to the same audit record. The
1769 * (timestamp,serial) tuple is unique for each syscall and is live from
1770 * syscall entry to syscall exit.
1772 * NOTE: Another possibility is to store the formatted records off the
1773 * audit context (for those records that have a context), and emit them
1774 * all at syscall exit. However, this could delay the reporting of
1775 * significant errors until syscall exit (or never, if the system
1778 unsigned int audit_serial(void)
1780 static atomic_t serial = ATOMIC_INIT(0);
1782 return atomic_add_return(1, &serial);
1785 static inline void audit_get_stamp(struct audit_context *ctx,
1786 struct timespec64 *t, unsigned int *serial)
1788 if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
1789 ktime_get_coarse_real_ts64(t);
1790 *serial = audit_serial();
1795 * audit_log_start - obtain an audit buffer
1796 * @ctx: audit_context (may be NULL)
1797 * @gfp_mask: type of allocation
1798 * @type: audit message type
1800 * Returns audit_buffer pointer on success or NULL on error.
1802 * Obtain an audit buffer. This routine does locking to obtain the
1803 * audit buffer, but then no locking is required for calls to
1804 * audit_log_*format. If the task (ctx) is a task that is currently in a
1805 * syscall, then the syscall is marked as auditable and an audit record
1806 * will be written at syscall exit. If there is no associated task, then
1807 * task context (ctx) should be NULL.
1809 struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1812 struct audit_buffer *ab;
1813 struct timespec64 t;
1814 unsigned int serial;
1816 if (audit_initialized != AUDIT_INITIALIZED)
1819 if (unlikely(!audit_filter(type, AUDIT_FILTER_EXCLUDE)))
1822 /* NOTE: don't ever fail/sleep on these two conditions:
1823 * 1. auditd generated record - since we need auditd to drain the
1824 * queue; also, when we are checking for auditd, compare PIDs using
1825 * task_tgid_vnr() since auditd_pid is set in audit_receive_msg()
1826 * using a PID anchored in the caller's namespace
1827 * 2. generator holding the audit_cmd_mutex - we don't want to block
1828 * while holding the mutex */
1829 if (!(auditd_test_task(current) || audit_ctl_owner_current())) {
1830 long stime = audit_backlog_wait_time;
1832 while (audit_backlog_limit &&
1833 (skb_queue_len(&audit_queue) > audit_backlog_limit)) {
1834 /* wake kauditd to try and flush the queue */
1835 wake_up_interruptible(&kauditd_wait);
1837 /* sleep if we are allowed and we haven't exhausted our
1838 * backlog wait limit */
1839 if (gfpflags_allow_blocking(gfp_mask) && (stime > 0)) {
1842 DECLARE_WAITQUEUE(wait, current);
1844 add_wait_queue_exclusive(&audit_backlog_wait,
1846 set_current_state(TASK_UNINTERRUPTIBLE);
1847 stime = schedule_timeout(rtime);
1848 atomic_add(rtime - stime, &audit_backlog_wait_time_actual);
1849 remove_wait_queue(&audit_backlog_wait, &wait);
1851 if (audit_rate_check() && printk_ratelimit())
1852 pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
1853 skb_queue_len(&audit_queue),
1854 audit_backlog_limit);
1855 audit_log_lost("backlog limit exceeded");
1861 ab = audit_buffer_alloc(ctx, gfp_mask, type);
1863 audit_log_lost("out of memory in audit_log_start");
1867 audit_get_stamp(ab->ctx, &t, &serial);
1868 audit_log_format(ab, "audit(%llu.%03lu:%u): ",
1869 (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
1875 * audit_expand - expand skb in the audit buffer
1877 * @extra: space to add at tail of the skb
1879 * Returns 0 (no space) on failed expansion, or available space if
1882 static inline int audit_expand(struct audit_buffer *ab, int extra)
1884 struct sk_buff *skb = ab->skb;
1885 int oldtail = skb_tailroom(skb);
1886 int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1887 int newtail = skb_tailroom(skb);
1890 audit_log_lost("out of memory in audit_expand");
1894 skb->truesize += newtail - oldtail;
1899 * Format an audit message into the audit buffer. If there isn't enough
1900 * room in the audit buffer, more room will be allocated and vsnprint
1901 * will be called a second time. Currently, we assume that a printk
1902 * can't format message larger than 1024 bytes, so we don't either.
1904 static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1908 struct sk_buff *skb;
1916 avail = skb_tailroom(skb);
1918 avail = audit_expand(ab, AUDIT_BUFSIZ);
1922 va_copy(args2, args);
1923 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1925 /* The printk buffer is 1024 bytes long, so if we get
1926 * here and AUDIT_BUFSIZ is at least 1024, then we can
1927 * log everything that printk could have logged. */
1928 avail = audit_expand(ab,
1929 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1932 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1943 * audit_log_format - format a message into the audit buffer.
1945 * @fmt: format string
1946 * @...: optional parameters matching @fmt string
1948 * All the work is done in audit_log_vformat.
1950 void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1956 va_start(args, fmt);
1957 audit_log_vformat(ab, fmt, args);
1962 * audit_log_n_hex - convert a buffer to hex and append it to the audit skb
1963 * @ab: the audit_buffer
1964 * @buf: buffer to convert to hex
1965 * @len: length of @buf to be converted
1967 * No return value; failure to expand is silently ignored.
1969 * This function will take the passed buf and convert it into a string of
1970 * ascii hex digits. The new string is placed onto the skb.
1972 void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
1975 int i, avail, new_len;
1977 struct sk_buff *skb;
1984 avail = skb_tailroom(skb);
1986 if (new_len >= avail) {
1987 /* Round the buffer request up to the next multiple */
1988 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1989 avail = audit_expand(ab, new_len);
1994 ptr = skb_tail_pointer(skb);
1995 for (i = 0; i < len; i++)
1996 ptr = hex_byte_pack_upper(ptr, buf[i]);
1998 skb_put(skb, len << 1); /* new string is twice the old string */
2002 * Format a string of no more than slen characters into the audit buffer,
2003 * enclosed in quote marks.
2005 void audit_log_n_string(struct audit_buffer *ab, const char *string,
2010 struct sk_buff *skb;
2017 avail = skb_tailroom(skb);
2018 new_len = slen + 3; /* enclosing quotes + null terminator */
2019 if (new_len > avail) {
2020 avail = audit_expand(ab, new_len);
2024 ptr = skb_tail_pointer(skb);
2026 memcpy(ptr, string, slen);
2030 skb_put(skb, slen + 2); /* don't include null terminator */
2034 * audit_string_contains_control - does a string need to be logged in hex
2035 * @string: string to be checked
2036 * @len: max length of the string to check
2038 bool audit_string_contains_control(const char *string, size_t len)
2040 const unsigned char *p;
2041 for (p = string; p < (const unsigned char *)string + len; p++) {
2042 if (*p == '"' || *p < 0x21 || *p > 0x7e)
2049 * audit_log_n_untrustedstring - log a string that may contain random characters
2051 * @len: length of string (not including trailing null)
2052 * @string: string to be logged
2054 * This code will escape a string that is passed to it if the string
2055 * contains a control character, unprintable character, double quote mark,
2056 * or a space. Unescaped strings will start and end with a double quote mark.
2057 * Strings that are escaped are printed in hex (2 digits per char).
2059 * The caller specifies the number of characters in the string to log, which may
2060 * or may not be the entire string.
2062 void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
2065 if (audit_string_contains_control(string, len))
2066 audit_log_n_hex(ab, string, len);
2068 audit_log_n_string(ab, string, len);
2072 * audit_log_untrustedstring - log a string that may contain random characters
2074 * @string: string to be logged
2076 * Same as audit_log_n_untrustedstring(), except that strlen is used to
2077 * determine string length.
2079 void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
2081 audit_log_n_untrustedstring(ab, string, strlen(string));
2084 /* This is a helper-function to print the escaped d_path */
2085 void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
2086 const struct path *path)
2091 audit_log_format(ab, "%s", prefix);
2093 /* We will allow 11 spaces for ' (deleted)' to be appended */
2094 pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
2096 audit_log_format(ab, "\"<no_memory>\"");
2099 p = d_path(path, pathname, PATH_MAX+11);
2100 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
2101 /* FIXME: can we save some information here? */
2102 audit_log_format(ab, "\"<too_long>\"");
2104 audit_log_untrustedstring(ab, p);
2108 void audit_log_session_info(struct audit_buffer *ab)
2110 unsigned int sessionid = audit_get_sessionid(current);
2111 uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
2113 audit_log_format(ab, "auid=%u ses=%u", auid, sessionid);
2116 void audit_log_key(struct audit_buffer *ab, char *key)
2118 audit_log_format(ab, " key=");
2120 audit_log_untrustedstring(ab, key);
2122 audit_log_format(ab, "(null)");
2125 int audit_log_task_context(struct audit_buffer *ab)
2132 security_task_getsecid(current, &sid);
2136 error = security_secid_to_secctx(sid, &ctx, &len);
2138 if (error != -EINVAL)
2143 audit_log_format(ab, " subj=%s", ctx);
2144 security_release_secctx(ctx, len);
2148 audit_panic("error in audit_log_task_context");
2151 EXPORT_SYMBOL(audit_log_task_context);
2153 void audit_log_d_path_exe(struct audit_buffer *ab,
2154 struct mm_struct *mm)
2156 struct file *exe_file;
2161 exe_file = get_mm_exe_file(mm);
2165 audit_log_d_path(ab, " exe=", &exe_file->f_path);
2169 audit_log_format(ab, " exe=(null)");
2172 struct tty_struct *audit_get_tty(void)
2174 struct tty_struct *tty = NULL;
2175 unsigned long flags;
2177 spin_lock_irqsave(¤t->sighand->siglock, flags);
2178 if (current->signal)
2179 tty = tty_kref_get(current->signal->tty);
2180 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
2184 void audit_put_tty(struct tty_struct *tty)
2189 void audit_log_task_info(struct audit_buffer *ab)
2191 const struct cred *cred;
2192 char comm[sizeof(current->comm)];
2193 struct tty_struct *tty;
2198 cred = current_cred();
2199 tty = audit_get_tty();
2200 audit_log_format(ab,
2201 " ppid=%d pid=%d auid=%u uid=%u gid=%u"
2202 " euid=%u suid=%u fsuid=%u"
2203 " egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
2204 task_ppid_nr(current),
2205 task_tgid_nr(current),
2206 from_kuid(&init_user_ns, audit_get_loginuid(current)),
2207 from_kuid(&init_user_ns, cred->uid),
2208 from_kgid(&init_user_ns, cred->gid),
2209 from_kuid(&init_user_ns, cred->euid),
2210 from_kuid(&init_user_ns, cred->suid),
2211 from_kuid(&init_user_ns, cred->fsuid),
2212 from_kgid(&init_user_ns, cred->egid),
2213 from_kgid(&init_user_ns, cred->sgid),
2214 from_kgid(&init_user_ns, cred->fsgid),
2215 tty ? tty_name(tty) : "(none)",
2216 audit_get_sessionid(current));
2218 audit_log_format(ab, " comm=");
2219 audit_log_untrustedstring(ab, get_task_comm(comm, current));
2220 audit_log_d_path_exe(ab, current->mm);
2221 audit_log_task_context(ab);
2223 EXPORT_SYMBOL(audit_log_task_info);
2226 * audit_log_path_denied - report a path restriction denial
2227 * @type: audit message type (AUDIT_ANOM_LINK, AUDIT_ANOM_CREAT, etc)
2228 * @operation: specific operation name
2230 void audit_log_path_denied(int type, const char *operation)
2232 struct audit_buffer *ab;
2234 if (!audit_enabled || audit_dummy_context())
2237 /* Generate log with subject, operation, outcome. */
2238 ab = audit_log_start(audit_context(), GFP_KERNEL, type);
2241 audit_log_format(ab, "op=%s", operation);
2242 audit_log_task_info(ab);
2243 audit_log_format(ab, " res=0");
2247 /* global counter which is incremented every time something logs in */
2248 static atomic_t session_id = ATOMIC_INIT(0);
2250 static int audit_set_loginuid_perm(kuid_t loginuid)
2252 /* if we are unset, we don't need privs */
2253 if (!audit_loginuid_set(current))
2255 /* if AUDIT_FEATURE_LOGINUID_IMMUTABLE means never ever allow a change*/
2256 if (is_audit_feature_set(AUDIT_FEATURE_LOGINUID_IMMUTABLE))
2258 /* it is set, you need permission */
2259 if (!capable(CAP_AUDIT_CONTROL))
2261 /* reject if this is not an unset and we don't allow that */
2262 if (is_audit_feature_set(AUDIT_FEATURE_ONLY_UNSET_LOGINUID)
2263 && uid_valid(loginuid))
2268 static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
2269 unsigned int oldsessionid,
2270 unsigned int sessionid, int rc)
2272 struct audit_buffer *ab;
2273 uid_t uid, oldloginuid, loginuid;
2274 struct tty_struct *tty;
2279 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_LOGIN);
2283 uid = from_kuid(&init_user_ns, task_uid(current));
2284 oldloginuid = from_kuid(&init_user_ns, koldloginuid);
2285 loginuid = from_kuid(&init_user_ns, kloginuid),
2286 tty = audit_get_tty();
2288 audit_log_format(ab, "pid=%d uid=%u", task_tgid_nr(current), uid);
2289 audit_log_task_context(ab);
2290 audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",
2291 oldloginuid, loginuid, tty ? tty_name(tty) : "(none)",
2292 oldsessionid, sessionid, !rc);
2298 * audit_set_loginuid - set current task's loginuid
2299 * @loginuid: loginuid value
2303 * Called (set) from fs/proc/base.c::proc_loginuid_write().
2305 int audit_set_loginuid(kuid_t loginuid)
2307 unsigned int oldsessionid, sessionid = AUDIT_SID_UNSET;
2311 oldloginuid = audit_get_loginuid(current);
2312 oldsessionid = audit_get_sessionid(current);
2314 rc = audit_set_loginuid_perm(loginuid);
2318 /* are we setting or clearing? */
2319 if (uid_valid(loginuid)) {
2320 sessionid = (unsigned int)atomic_inc_return(&session_id);
2321 if (unlikely(sessionid == AUDIT_SID_UNSET))
2322 sessionid = (unsigned int)atomic_inc_return(&session_id);
2325 current->sessionid = sessionid;
2326 current->loginuid = loginuid;
2328 audit_log_set_loginuid(oldloginuid, loginuid, oldsessionid, sessionid, rc);
2333 * audit_signal_info - record signal info for shutting down audit subsystem
2334 * @sig: signal value
2335 * @t: task being signaled
2337 * If the audit subsystem is being terminated, record the task (pid)
2338 * and uid that is doing that.
2340 int audit_signal_info(int sig, struct task_struct *t)
2342 kuid_t uid = current_uid(), auid;
2344 if (auditd_test_task(t) &&
2345 (sig == SIGTERM || sig == SIGHUP ||
2346 sig == SIGUSR1 || sig == SIGUSR2)) {
2347 audit_sig_pid = task_tgid_nr(current);
2348 auid = audit_get_loginuid(current);
2349 if (uid_valid(auid))
2350 audit_sig_uid = auid;
2352 audit_sig_uid = uid;
2353 security_task_getsecid(current, &audit_sig_sid);
2356 return audit_signal_info_syscall(t);
2360 * audit_log_end - end one audit record
2361 * @ab: the audit_buffer
2363 * We can not do a netlink send inside an irq context because it blocks (last
2364 * arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a
2365 * queue and a tasklet is scheduled to remove them from the queue outside the
2366 * irq context. May be called in any context.
2368 void audit_log_end(struct audit_buffer *ab)
2370 struct sk_buff *skb;
2371 struct nlmsghdr *nlh;
2376 if (audit_rate_check()) {
2380 /* setup the netlink header, see the comments in
2381 * kauditd_send_multicast_skb() for length quirks */
2382 nlh = nlmsg_hdr(skb);
2383 nlh->nlmsg_len = skb->len - NLMSG_HDRLEN;
2385 /* queue the netlink packet and poke the kauditd thread */
2386 skb_queue_tail(&audit_queue, skb);
2387 wake_up_interruptible(&kauditd_wait);
2389 audit_log_lost("rate limit exceeded");
2391 audit_buffer_free(ab);
2395 * audit_log - Log an audit record
2396 * @ctx: audit context
2397 * @gfp_mask: type of allocation
2398 * @type: audit message type
2399 * @fmt: format string to use
2400 * @...: variable parameters matching the format string
2402 * This is a convenience function that calls audit_log_start,
2403 * audit_log_vformat, and audit_log_end. It may be called
2406 void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
2407 const char *fmt, ...)
2409 struct audit_buffer *ab;
2412 ab = audit_log_start(ctx, gfp_mask, type);
2414 va_start(args, fmt);
2415 audit_log_vformat(ab, fmt, args);
2421 EXPORT_SYMBOL(audit_log_start);
2422 EXPORT_SYMBOL(audit_log_end);
2423 EXPORT_SYMBOL(audit_log_format);
2424 EXPORT_SYMBOL(audit_log);