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 static struct auditd_connection {
110 } *auditd_conn = NULL;
111 static DEFINE_SPINLOCK(auditd_conn_lock);
113 /* If audit_rate_limit is non-zero, limit the rate of sending audit records
114 * to that number per second. This prevents DoS attacks, but results in
115 * audit records being dropped. */
116 static u32 audit_rate_limit;
118 /* Number of outstanding audit_buffers allowed.
119 * When set to zero, this means unlimited. */
120 static u32 audit_backlog_limit = 64;
121 #define AUDIT_BACKLOG_WAIT_TIME (60 * HZ)
122 static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
124 /* The identity of the user shutting down the audit system. */
125 kuid_t audit_sig_uid = INVALID_UID;
126 pid_t audit_sig_pid = -1;
127 u32 audit_sig_sid = 0;
129 /* Records can be lost in several ways:
130 0) [suppressed in audit_alloc]
131 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
132 2) out of memory in audit_log_move [alloc_skb]
133 3) suppressed due to audit_rate_limit
134 4) suppressed due to audit_backlog_limit
136 static atomic_t audit_lost = ATOMIC_INIT(0);
138 /* Hash for inode-based rules */
139 struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
141 static struct kmem_cache *audit_buffer_cache;
143 /* queue msgs to send via kauditd_task */
144 static struct sk_buff_head audit_queue;
145 /* queue msgs due to temporary unicast send problems */
146 static struct sk_buff_head audit_retry_queue;
147 /* queue msgs waiting for new auditd connection */
148 static struct sk_buff_head audit_hold_queue;
150 /* queue servicing thread */
151 static struct task_struct *kauditd_task;
152 static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
154 /* waitqueue for callers who are blocked on the audit backlog */
155 static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
157 static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION,
162 static char *audit_feature_names[2] = {
163 "only_unset_loginuid",
164 "loginuid_immutable",
168 * struct audit_ctl_mutex - serialize requests from userspace
169 * @lock: the mutex used for locking
170 * @owner: the task which owns the lock
173 * This is the lock struct used to ensure we only process userspace requests
174 * in an orderly fashion. We can't simply use a mutex/lock here because we
175 * need to track lock ownership so we don't end up blocking the lock owner in
176 * audit_log_start() or similar.
178 static struct audit_ctl_mutex {
183 /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
184 * audit records. Since printk uses a 1024 byte buffer, this buffer
185 * should be at least that large. */
186 #define AUDIT_BUFSIZ 1024
188 /* The audit_buffer is used when formatting an audit record. The caller
189 * locks briefly to get the record off the freelist or to allocate the
190 * buffer, and locks briefly to send the buffer to the netlink layer or
191 * to place it on a transmit queue. Multiple audit_buffers can be in
192 * use simultaneously. */
193 struct audit_buffer {
194 struct sk_buff *skb; /* formatted skb ready to send */
195 struct audit_context *ctx; /* NULL or associated context */
206 * auditd_test_task - Check to see if a given task is an audit daemon
207 * @task: the task to check
210 * Return 1 if the task is a registered audit daemon, 0 otherwise.
212 int auditd_test_task(struct task_struct *task)
215 struct auditd_connection *ac;
218 ac = rcu_dereference(auditd_conn);
219 rc = (ac && ac->pid == task_tgid(task) ? 1 : 0);
226 * audit_ctl_lock - Take the audit control lock
228 void audit_ctl_lock(void)
230 mutex_lock(&audit_cmd_mutex.lock);
231 audit_cmd_mutex.owner = current;
235 * audit_ctl_unlock - Drop the audit control lock
237 void audit_ctl_unlock(void)
239 audit_cmd_mutex.owner = NULL;
240 mutex_unlock(&audit_cmd_mutex.lock);
244 * audit_ctl_owner_current - Test to see if the current task owns the lock
247 * Return true if the current task owns the audit control lock, false if it
248 * doesn't own the lock.
250 static bool audit_ctl_owner_current(void)
252 return (current == audit_cmd_mutex.owner);
256 * auditd_pid_vnr - Return the auditd PID relative to the namespace
259 * Returns the PID in relation to the namespace, 0 on failure.
261 static pid_t auditd_pid_vnr(void)
264 const struct auditd_connection *ac;
267 ac = rcu_dereference(auditd_conn);
271 pid = pid_vnr(ac->pid);
278 * audit_get_sk - Return the audit socket for the given network namespace
279 * @net: the destination network namespace
282 * Returns the sock pointer if valid, NULL otherwise. The caller must ensure
283 * that a reference is held for the network namespace while the sock is in use.
285 static struct sock *audit_get_sk(const struct net *net)
287 struct audit_net *aunet;
292 aunet = net_generic(net, audit_net_id);
296 void audit_panic(const char *message)
298 switch (audit_failure) {
299 case AUDIT_FAIL_SILENT:
301 case AUDIT_FAIL_PRINTK:
302 if (printk_ratelimit())
303 pr_err("%s\n", message);
305 case AUDIT_FAIL_PANIC:
306 panic("audit: %s\n", message);
311 static inline int audit_rate_check(void)
313 static unsigned long last_check = 0;
314 static int messages = 0;
315 static DEFINE_SPINLOCK(lock);
318 unsigned long elapsed;
321 if (!audit_rate_limit) return 1;
323 spin_lock_irqsave(&lock, flags);
324 if (++messages < audit_rate_limit) {
328 elapsed = now - last_check;
335 spin_unlock_irqrestore(&lock, flags);
341 * audit_log_lost - conditionally log lost audit message event
342 * @message: the message stating reason for lost audit message
344 * Emit at least 1 message per second, even if audit_rate_check is
346 * Always increment the lost messages counter.
348 void audit_log_lost(const char *message)
350 static unsigned long last_msg = 0;
351 static DEFINE_SPINLOCK(lock);
356 atomic_inc(&audit_lost);
358 print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
361 spin_lock_irqsave(&lock, flags);
363 if (now - last_msg > HZ) {
367 spin_unlock_irqrestore(&lock, flags);
371 if (printk_ratelimit())
372 pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
373 atomic_read(&audit_lost),
375 audit_backlog_limit);
376 audit_panic(message);
380 static int audit_log_config_change(char *function_name, u32 new, u32 old,
383 struct audit_buffer *ab;
386 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
389 audit_log_format(ab, "op=set %s=%u old=%u ", function_name, new, old);
390 audit_log_session_info(ab);
391 rc = audit_log_task_context(ab);
393 allow_changes = 0; /* Something weird, deny request */
394 audit_log_format(ab, " res=%d", allow_changes);
399 static int audit_do_config_change(char *function_name, u32 *to_change, u32 new)
401 int allow_changes, rc = 0;
402 u32 old = *to_change;
404 /* check if we are locked */
405 if (audit_enabled == AUDIT_LOCKED)
410 if (audit_enabled != AUDIT_OFF) {
411 rc = audit_log_config_change(function_name, new, old, allow_changes);
416 /* If we are allowed, make the change */
417 if (allow_changes == 1)
419 /* Not allowed, update reason */
425 static int audit_set_rate_limit(u32 limit)
427 return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit);
430 static int audit_set_backlog_limit(u32 limit)
432 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit);
435 static int audit_set_backlog_wait_time(u32 timeout)
437 return audit_do_config_change("audit_backlog_wait_time",
438 &audit_backlog_wait_time, timeout);
441 static int audit_set_enabled(u32 state)
444 if (state > AUDIT_LOCKED)
447 rc = audit_do_config_change("audit_enabled", &audit_enabled, state);
449 audit_ever_enabled |= !!state;
454 static int audit_set_failure(u32 state)
456 if (state != AUDIT_FAIL_SILENT
457 && state != AUDIT_FAIL_PRINTK
458 && state != AUDIT_FAIL_PANIC)
461 return audit_do_config_change("audit_failure", &audit_failure, state);
465 * auditd_conn_free - RCU helper to release an auditd connection struct
469 * Drop any references inside the auditd connection tracking struct and free
472 static void auditd_conn_free(struct rcu_head *rcu)
474 struct auditd_connection *ac;
476 ac = container_of(rcu, struct auditd_connection, rcu);
483 * auditd_set - Set/Reset the auditd connection state
485 * @portid: auditd netlink portid
486 * @net: auditd network namespace pointer
487 * @skb: the netlink command from the audit daemon
488 * @ack: netlink ack flag, cleared if ack'd here
491 * This function will obtain and drop network namespace references as
492 * necessary. Returns zero on success, negative values on failure.
494 static int auditd_set(struct pid *pid, u32 portid, struct net *net,
495 struct sk_buff *skb, bool *ack)
498 struct auditd_connection *ac_old, *ac_new;
499 struct nlmsghdr *nlh;
504 ac_new = kzalloc(sizeof(*ac_new), GFP_KERNEL);
507 ac_new->pid = get_pid(pid);
508 ac_new->portid = portid;
509 ac_new->net = get_net(net);
511 /* send the ack now to avoid a race with the queue backlog */
513 nlh = nlmsg_hdr(skb);
514 netlink_ack(skb, nlh, 0, NULL);
518 spin_lock_irqsave(&auditd_conn_lock, flags);
519 ac_old = rcu_dereference_protected(auditd_conn,
520 lockdep_is_held(&auditd_conn_lock));
521 rcu_assign_pointer(auditd_conn, ac_new);
522 spin_unlock_irqrestore(&auditd_conn_lock, flags);
525 call_rcu(&ac_old->rcu, auditd_conn_free);
531 * kauditd_print_skb - Print the audit record to the ring buffer
534 * Whatever the reason, this packet may not make it to the auditd connection
535 * so write it via printk so the information isn't completely lost.
537 static void kauditd_printk_skb(struct sk_buff *skb)
539 struct nlmsghdr *nlh = nlmsg_hdr(skb);
540 char *data = nlmsg_data(nlh);
542 if (nlh->nlmsg_type != AUDIT_EOE && printk_ratelimit())
543 pr_notice("type=%d %s\n", nlh->nlmsg_type, data);
547 * kauditd_rehold_skb - Handle a audit record send failure in the hold queue
549 * @error: error code (unused)
552 * This should only be used by the kauditd_thread when it fails to flush the
555 static void kauditd_rehold_skb(struct sk_buff *skb, __always_unused int error)
557 /* put the record back in the queue */
558 skb_queue_tail(&audit_hold_queue, skb);
562 * kauditd_hold_skb - Queue an audit record, waiting for auditd
567 * Queue the audit record, waiting for an instance of auditd. When this
568 * function is called we haven't given up yet on sending the record, but things
569 * are not looking good. The first thing we want to do is try to write the
570 * record via printk and then see if we want to try and hold on to the record
571 * and queue it, if we have room. If we want to hold on to the record, but we
572 * don't have room, record a record lost message.
574 static void kauditd_hold_skb(struct sk_buff *skb, int error)
576 /* at this point it is uncertain if we will ever send this to auditd so
577 * try to send the message via printk before we go any further */
578 kauditd_printk_skb(skb);
580 /* can we just silently drop the message? */
584 /* the hold queue is only for when the daemon goes away completely,
585 * not -EAGAIN failures; if we are in a -EAGAIN state requeue the
586 * record on the retry queue unless it's full, in which case drop it
588 if (error == -EAGAIN) {
589 if (!audit_backlog_limit ||
590 skb_queue_len(&audit_retry_queue) < audit_backlog_limit) {
591 skb_queue_tail(&audit_retry_queue, skb);
594 audit_log_lost("kauditd retry queue overflow");
598 /* if we have room in the hold queue, queue the message */
599 if (!audit_backlog_limit ||
600 skb_queue_len(&audit_hold_queue) < audit_backlog_limit) {
601 skb_queue_tail(&audit_hold_queue, skb);
605 /* we have no other options - drop the message */
606 audit_log_lost("kauditd hold queue overflow");
612 * kauditd_retry_skb - Queue an audit record, attempt to send again to auditd
614 * @error: error code (unused)
617 * Not as serious as kauditd_hold_skb() as we still have a connected auditd,
618 * but for some reason we are having problems sending it audit records so
619 * queue the given record and attempt to resend.
621 static void kauditd_retry_skb(struct sk_buff *skb, __always_unused int error)
623 if (!audit_backlog_limit ||
624 skb_queue_len(&audit_retry_queue) < audit_backlog_limit) {
625 skb_queue_tail(&audit_retry_queue, skb);
629 /* we have to drop the record, send it via printk as a last effort */
630 kauditd_printk_skb(skb);
631 audit_log_lost("kauditd retry queue overflow");
636 * auditd_reset - Disconnect the auditd connection
637 * @ac: auditd connection state
640 * Break the auditd/kauditd connection and move all the queued records into the
641 * hold queue in case auditd reconnects. It is important to note that the @ac
642 * pointer should never be dereferenced inside this function as it may be NULL
643 * or invalid, you can only compare the memory address! If @ac is NULL then
644 * the connection will always be reset.
646 static void auditd_reset(const struct auditd_connection *ac)
650 struct auditd_connection *ac_old;
652 /* if it isn't already broken, break the connection */
653 spin_lock_irqsave(&auditd_conn_lock, flags);
654 ac_old = rcu_dereference_protected(auditd_conn,
655 lockdep_is_held(&auditd_conn_lock));
656 if (ac && ac != ac_old) {
657 /* someone already registered a new auditd connection */
658 spin_unlock_irqrestore(&auditd_conn_lock, flags);
661 rcu_assign_pointer(auditd_conn, NULL);
662 spin_unlock_irqrestore(&auditd_conn_lock, flags);
665 call_rcu(&ac_old->rcu, auditd_conn_free);
667 /* flush the retry queue to the hold queue, but don't touch the main
668 * queue since we need to process that normally for multicast */
669 while ((skb = skb_dequeue(&audit_retry_queue)))
670 kauditd_hold_skb(skb, -ECONNREFUSED);
674 * auditd_send_unicast_skb - Send a record via unicast to auditd
678 * Send a skb to the audit daemon, returns positive/zero values on success and
679 * negative values on failure; in all cases the skb will be consumed by this
680 * function. If the send results in -ECONNREFUSED the connection with auditd
681 * will be reset. This function may sleep so callers should not hold any locks
682 * where this would cause a problem.
684 static int auditd_send_unicast_skb(struct sk_buff *skb)
690 struct auditd_connection *ac;
692 /* NOTE: we can't call netlink_unicast while in the RCU section so
693 * take a reference to the network namespace and grab local
694 * copies of the namespace, the sock, and the portid; the
695 * namespace and sock aren't going to go away while we hold a
696 * reference and if the portid does become invalid after the RCU
697 * section netlink_unicast() should safely return an error */
700 ac = rcu_dereference(auditd_conn);
707 net = get_net(ac->net);
708 sk = audit_get_sk(net);
712 rc = netlink_unicast(sk, skb, portid, 0);
720 if (ac && rc == -ECONNREFUSED)
726 * kauditd_send_queue - Helper for kauditd_thread to flush skb queues
727 * @sk: the sending sock
728 * @portid: the netlink destination
729 * @queue: the skb queue to process
730 * @retry_limit: limit on number of netlink unicast failures
731 * @skb_hook: per-skb hook for additional processing
732 * @err_hook: hook called if the skb fails the netlink unicast send
735 * Run through the given queue and attempt to send the audit records to auditd,
736 * returns zero on success, negative values on failure. It is up to the caller
737 * to ensure that the @sk is valid for the duration of this function.
740 static int kauditd_send_queue(struct sock *sk, u32 portid,
741 struct sk_buff_head *queue,
742 unsigned int retry_limit,
743 void (*skb_hook)(struct sk_buff *skb),
744 void (*err_hook)(struct sk_buff *skb, int error))
747 struct sk_buff *skb = NULL;
748 struct sk_buff *skb_tail;
749 unsigned int failed = 0;
751 /* NOTE: kauditd_thread takes care of all our locking, we just use
752 * the netlink info passed to us (e.g. sk and portid) */
754 skb_tail = skb_peek_tail(queue);
755 while ((skb != skb_tail) && (skb = skb_dequeue(queue))) {
756 /* call the skb_hook for each skb we touch */
760 /* can we send to anyone via unicast? */
763 (*err_hook)(skb, -ECONNREFUSED);
768 /* grab an extra skb reference in case of error */
770 rc = netlink_unicast(sk, skb, portid, 0);
772 /* send failed - try a few times unless fatal error */
773 if (++failed >= retry_limit ||
774 rc == -ECONNREFUSED || rc == -EPERM) {
777 (*err_hook)(skb, rc);
780 /* continue to drain the queue */
785 /* skb sent - drop the extra reference and continue */
791 return (rc >= 0 ? 0 : rc);
795 * kauditd_send_multicast_skb - Send a record to any multicast listeners
799 * Write a multicast message to anyone listening in the initial network
800 * namespace. This function doesn't consume an skb as might be expected since
801 * it has to copy it anyways.
803 static void kauditd_send_multicast_skb(struct sk_buff *skb)
805 struct sk_buff *copy;
806 struct sock *sock = audit_get_sk(&init_net);
807 struct nlmsghdr *nlh;
809 /* NOTE: we are not taking an additional reference for init_net since
810 * we don't have to worry about it going away */
812 if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
816 * The seemingly wasteful skb_copy() rather than bumping the refcount
817 * using skb_get() is necessary because non-standard mods are made to
818 * the skb by the original kaudit unicast socket send routine. The
819 * existing auditd daemon assumes this breakage. Fixing this would
820 * require co-ordinating a change in the established protocol between
821 * the kaudit kernel subsystem and the auditd userspace code. There is
822 * no reason for new multicast clients to continue with this
825 copy = skb_copy(skb, GFP_KERNEL);
828 nlh = nlmsg_hdr(copy);
829 nlh->nlmsg_len = skb->len;
831 nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL);
835 * kauditd_thread - Worker thread to send audit records to userspace
838 static int kauditd_thread(void *dummy)
842 struct net *net = NULL;
843 struct sock *sk = NULL;
844 struct auditd_connection *ac;
846 #define UNICAST_RETRIES 5
849 while (!kthread_should_stop()) {
850 /* NOTE: see the lock comments in auditd_send_unicast_skb() */
852 ac = rcu_dereference(auditd_conn);
857 net = get_net(ac->net);
858 sk = audit_get_sk(net);
862 /* attempt to flush the hold queue */
863 rc = kauditd_send_queue(sk, portid,
864 &audit_hold_queue, UNICAST_RETRIES,
865 NULL, kauditd_rehold_skb);
872 /* attempt to flush the retry queue */
873 rc = kauditd_send_queue(sk, portid,
874 &audit_retry_queue, UNICAST_RETRIES,
875 NULL, kauditd_hold_skb);
883 /* process the main queue - do the multicast send and attempt
884 * unicast, dump failed record sends to the retry queue; if
885 * sk == NULL due to previous failures we will just do the
886 * multicast send and move the record to the hold queue */
887 rc = kauditd_send_queue(sk, portid, &audit_queue, 1,
888 kauditd_send_multicast_skb,
890 kauditd_retry_skb : kauditd_hold_skb));
895 /* drop our netns reference, no auditd sends past this line */
901 /* we have processed all the queues so wake everyone */
902 wake_up(&audit_backlog_wait);
904 /* NOTE: we want to wake up if there is anything on the queue,
905 * regardless of if an auditd is connected, as we need to
906 * do the multicast send and rotate records from the
907 * main queue to the retry/hold queues */
908 wait_event_freezable(kauditd_wait,
909 (skb_queue_len(&audit_queue) ? 1 : 0));
915 int audit_send_list_thread(void *_dest)
917 struct audit_netlink_list *dest = _dest;
919 struct sock *sk = audit_get_sk(dest->net);
921 /* wait for parent to finish and send an ACK */
925 while ((skb = __skb_dequeue(&dest->q)) != NULL)
926 netlink_unicast(sk, skb, dest->portid, 0);
934 struct sk_buff *audit_make_reply(int seq, int type, int done,
935 int multi, const void *payload, int size)
938 struct nlmsghdr *nlh;
940 int flags = multi ? NLM_F_MULTI : 0;
941 int t = done ? NLMSG_DONE : type;
943 skb = nlmsg_new(size, GFP_KERNEL);
947 nlh = nlmsg_put(skb, 0, seq, t, size, flags);
950 data = nlmsg_data(nlh);
951 memcpy(data, payload, size);
959 static void audit_free_reply(struct audit_reply *reply)
965 kfree_skb(reply->skb);
971 static int audit_send_reply_thread(void *arg)
973 struct audit_reply *reply = (struct audit_reply *)arg;
978 /* Ignore failure. It'll only happen if the sender goes away,
979 because our timeout is set to infinite. */
980 netlink_unicast(audit_get_sk(reply->net), reply->skb, reply->portid, 0);
982 audit_free_reply(reply);
987 * audit_send_reply - send an audit reply message via netlink
988 * @request_skb: skb of request we are replying to (used to target the reply)
989 * @seq: sequence number
990 * @type: audit message type
991 * @done: done (last) flag
992 * @multi: multi-part message flag
993 * @payload: payload data
994 * @size: payload size
996 * Allocates a skb, builds the netlink message, and sends it to the port id.
998 static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
999 int multi, const void *payload, int size)
1001 struct task_struct *tsk;
1002 struct audit_reply *reply;
1004 reply = kzalloc(sizeof(*reply), GFP_KERNEL);
1008 reply->skb = audit_make_reply(seq, type, done, multi, payload, size);
1011 reply->net = get_net(sock_net(NETLINK_CB(request_skb).sk));
1012 reply->portid = NETLINK_CB(request_skb).portid;
1014 tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
1021 audit_free_reply(reply);
1025 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
1028 static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
1032 /* Only support initial user namespace for now. */
1034 * We return ECONNREFUSED because it tricks userspace into thinking
1035 * that audit was not configured into the kernel. Lots of users
1036 * configure their PAM stack (because that's what the distro does)
1037 * to reject login if unable to send messages to audit. If we return
1038 * ECONNREFUSED the PAM stack thinks the kernel does not have audit
1039 * configured in and will let login proceed. If we return EPERM
1040 * userspace will reject all logins. This should be removed when we
1041 * support non init namespaces!!
1043 if (current_user_ns() != &init_user_ns)
1044 return -ECONNREFUSED;
1053 case AUDIT_GET_FEATURE:
1054 case AUDIT_SET_FEATURE:
1055 case AUDIT_LIST_RULES:
1056 case AUDIT_ADD_RULE:
1057 case AUDIT_DEL_RULE:
1058 case AUDIT_SIGNAL_INFO:
1062 case AUDIT_MAKE_EQUIV:
1063 /* Only support auditd and auditctl in initial pid namespace
1065 if (task_active_pid_ns(current) != &init_pid_ns)
1068 if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
1072 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1073 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1074 if (!netlink_capable(skb, CAP_AUDIT_WRITE))
1077 default: /* bad msg */
1084 static void audit_log_common_recv_msg(struct audit_context *context,
1085 struct audit_buffer **ab, u16 msg_type)
1087 uid_t uid = from_kuid(&init_user_ns, current_uid());
1088 pid_t pid = task_tgid_nr(current);
1090 if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
1095 *ab = audit_log_start(context, GFP_KERNEL, msg_type);
1098 audit_log_format(*ab, "pid=%d uid=%u ", pid, uid);
1099 audit_log_session_info(*ab);
1100 audit_log_task_context(*ab);
1103 static inline void audit_log_user_recv_msg(struct audit_buffer **ab,
1106 audit_log_common_recv_msg(NULL, ab, msg_type);
1109 int is_audit_feature_set(int i)
1111 return af.features & AUDIT_FEATURE_TO_MASK(i);
1115 static int audit_get_feature(struct sk_buff *skb)
1119 seq = nlmsg_hdr(skb)->nlmsg_seq;
1121 audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af));
1126 static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
1127 u32 old_lock, u32 new_lock, int res)
1129 struct audit_buffer *ab;
1131 if (audit_enabled == AUDIT_OFF)
1134 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_FEATURE_CHANGE);
1137 audit_log_task_info(ab);
1138 audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
1139 audit_feature_names[which], !!old_feature, !!new_feature,
1140 !!old_lock, !!new_lock, res);
1144 static int audit_set_feature(struct audit_features *uaf)
1148 BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
1150 /* if there is ever a version 2 we should handle that here */
1152 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1153 u32 feature = AUDIT_FEATURE_TO_MASK(i);
1154 u32 old_feature, new_feature, old_lock, new_lock;
1156 /* if we are not changing this feature, move along */
1157 if (!(feature & uaf->mask))
1160 old_feature = af.features & feature;
1161 new_feature = uaf->features & feature;
1162 new_lock = (uaf->lock | af.lock) & feature;
1163 old_lock = af.lock & feature;
1165 /* are we changing a locked feature? */
1166 if (old_lock && (new_feature != old_feature)) {
1167 audit_log_feature_change(i, old_feature, new_feature,
1168 old_lock, new_lock, 0);
1172 /* nothing invalid, do the changes */
1173 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1174 u32 feature = AUDIT_FEATURE_TO_MASK(i);
1175 u32 old_feature, new_feature, old_lock, new_lock;
1177 /* if we are not changing this feature, move along */
1178 if (!(feature & uaf->mask))
1181 old_feature = af.features & feature;
1182 new_feature = uaf->features & feature;
1183 old_lock = af.lock & feature;
1184 new_lock = (uaf->lock | af.lock) & feature;
1186 if (new_feature != old_feature)
1187 audit_log_feature_change(i, old_feature, new_feature,
1188 old_lock, new_lock, 1);
1191 af.features |= feature;
1193 af.features &= ~feature;
1194 af.lock |= new_lock;
1200 static int audit_replace(struct pid *pid)
1203 struct sk_buff *skb;
1205 pvnr = pid_vnr(pid);
1206 skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pvnr, sizeof(pvnr));
1209 return auditd_send_unicast_skb(skb);
1212 static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
1219 struct audit_buffer *ab;
1220 u16 msg_type = nlh->nlmsg_type;
1221 struct audit_sig_info *sig_data;
1225 err = audit_netlink_ok(skb, msg_type);
1229 seq = nlh->nlmsg_seq;
1230 data = nlmsg_data(nlh);
1231 data_len = nlmsg_len(nlh);
1235 struct audit_status s;
1236 memset(&s, 0, sizeof(s));
1237 s.enabled = audit_enabled;
1238 s.failure = audit_failure;
1239 /* NOTE: use pid_vnr() so the PID is relative to the current
1241 s.pid = auditd_pid_vnr();
1242 s.rate_limit = audit_rate_limit;
1243 s.backlog_limit = audit_backlog_limit;
1244 s.lost = atomic_read(&audit_lost);
1245 s.backlog = skb_queue_len(&audit_queue);
1246 s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL;
1247 s.backlog_wait_time = audit_backlog_wait_time;
1248 audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
1252 struct audit_status s;
1253 memset(&s, 0, sizeof(s));
1254 /* guard against past and future API changes */
1255 memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
1256 if (s.mask & AUDIT_STATUS_ENABLED) {
1257 err = audit_set_enabled(s.enabled);
1261 if (s.mask & AUDIT_STATUS_FAILURE) {
1262 err = audit_set_failure(s.failure);
1266 if (s.mask & AUDIT_STATUS_PID) {
1267 /* NOTE: we are using the vnr PID functions below
1268 * because the s.pid value is relative to the
1269 * namespace of the caller; at present this
1270 * doesn't matter much since you can really only
1271 * run auditd from the initial pid namespace, but
1272 * something to keep in mind if this changes */
1273 pid_t new_pid = s.pid;
1275 struct pid *req_pid = task_tgid(current);
1277 /* Sanity check - PID values must match. Setting
1278 * pid to 0 is how auditd ends auditing. */
1279 if (new_pid && (new_pid != pid_vnr(req_pid)))
1282 /* test the auditd connection */
1283 audit_replace(req_pid);
1285 auditd_pid = auditd_pid_vnr();
1287 /* replacing a healthy auditd is not allowed */
1289 audit_log_config_change("audit_pid",
1290 new_pid, auditd_pid, 0);
1293 /* only current auditd can unregister itself */
1294 if (pid_vnr(req_pid) != auditd_pid) {
1295 audit_log_config_change("audit_pid",
1296 new_pid, auditd_pid, 0);
1302 /* register a new auditd connection */
1303 err = auditd_set(req_pid,
1304 NETLINK_CB(skb).portid,
1305 sock_net(NETLINK_CB(skb).sk),
1307 if (audit_enabled != AUDIT_OFF)
1308 audit_log_config_change("audit_pid",
1315 /* try to process any backlog */
1316 wake_up_interruptible(&kauditd_wait);
1318 if (audit_enabled != AUDIT_OFF)
1319 audit_log_config_change("audit_pid",
1323 /* unregister the auditd connection */
1327 if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
1328 err = audit_set_rate_limit(s.rate_limit);
1332 if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
1333 err = audit_set_backlog_limit(s.backlog_limit);
1337 if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
1338 if (sizeof(s) > (size_t)nlh->nlmsg_len)
1340 if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
1342 err = audit_set_backlog_wait_time(s.backlog_wait_time);
1346 if (s.mask == AUDIT_STATUS_LOST) {
1347 u32 lost = atomic_xchg(&audit_lost, 0);
1349 audit_log_config_change("lost", 0, lost, 1);
1354 case AUDIT_GET_FEATURE:
1355 err = audit_get_feature(skb);
1359 case AUDIT_SET_FEATURE:
1360 if (data_len < sizeof(struct audit_features))
1362 err = audit_set_feature(data);
1367 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1368 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1369 if (!audit_enabled && msg_type != AUDIT_USER_AVC)
1371 /* exit early if there isn't at least one character to print */
1375 err = audit_filter(msg_type, AUDIT_FILTER_USER);
1376 if (err == 1) { /* match or error */
1380 if (msg_type == AUDIT_USER_TTY) {
1381 err = tty_audit_push();
1385 audit_log_user_recv_msg(&ab, msg_type);
1386 if (msg_type != AUDIT_USER_TTY) {
1387 /* ensure NULL termination */
1388 str[data_len - 1] = '\0';
1389 audit_log_format(ab, " msg='%.*s'",
1390 AUDIT_MESSAGE_TEXT_MAX,
1393 audit_log_format(ab, " data=");
1394 if (data_len > 0 && str[data_len - 1] == '\0')
1396 audit_log_n_untrustedstring(ab, str, data_len);
1401 case AUDIT_ADD_RULE:
1402 case AUDIT_DEL_RULE:
1403 if (data_len < sizeof(struct audit_rule_data))
1405 if (audit_enabled == AUDIT_LOCKED) {
1406 audit_log_common_recv_msg(audit_context(), &ab,
1407 AUDIT_CONFIG_CHANGE);
1408 audit_log_format(ab, " op=%s audit_enabled=%d res=0",
1409 msg_type == AUDIT_ADD_RULE ?
1410 "add_rule" : "remove_rule",
1415 err = audit_rule_change(msg_type, seq, data, data_len);
1417 case AUDIT_LIST_RULES:
1418 err = audit_list_rules_send(skb, seq);
1422 audit_log_common_recv_msg(audit_context(), &ab,
1423 AUDIT_CONFIG_CHANGE);
1424 audit_log_format(ab, " op=trim res=1");
1427 case AUDIT_MAKE_EQUIV: {
1430 size_t msglen = data_len;
1434 if (msglen < 2 * sizeof(u32))
1436 memcpy(sizes, bufp, 2 * sizeof(u32));
1437 bufp += 2 * sizeof(u32);
1438 msglen -= 2 * sizeof(u32);
1439 old = audit_unpack_string(&bufp, &msglen, sizes[0]);
1444 new = audit_unpack_string(&bufp, &msglen, sizes[1]);
1450 /* OK, here comes... */
1451 err = audit_tag_tree(old, new);
1453 audit_log_common_recv_msg(audit_context(), &ab,
1454 AUDIT_CONFIG_CHANGE);
1455 audit_log_format(ab, " op=make_equiv old=");
1456 audit_log_untrustedstring(ab, old);
1457 audit_log_format(ab, " new=");
1458 audit_log_untrustedstring(ab, new);
1459 audit_log_format(ab, " res=%d", !err);
1465 case AUDIT_SIGNAL_INFO:
1467 if (audit_sig_sid) {
1468 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
1472 sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
1475 security_release_secctx(ctx, len);
1478 sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
1479 sig_data->pid = audit_sig_pid;
1480 if (audit_sig_sid) {
1481 memcpy(sig_data->ctx, ctx, len);
1482 security_release_secctx(ctx, len);
1484 audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
1485 sig_data, sizeof(*sig_data) + len);
1488 case AUDIT_TTY_GET: {
1489 struct audit_tty_status s;
1492 t = READ_ONCE(current->signal->audit_tty);
1493 s.enabled = t & AUDIT_TTY_ENABLE;
1494 s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1496 audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
1499 case AUDIT_TTY_SET: {
1500 struct audit_tty_status s, old;
1501 struct audit_buffer *ab;
1504 memset(&s, 0, sizeof(s));
1505 /* guard against past and future API changes */
1506 memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
1507 /* check if new data is valid */
1508 if ((s.enabled != 0 && s.enabled != 1) ||
1509 (s.log_passwd != 0 && s.log_passwd != 1))
1513 t = READ_ONCE(current->signal->audit_tty);
1515 t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD);
1516 t = xchg(¤t->signal->audit_tty, t);
1518 old.enabled = t & AUDIT_TTY_ENABLE;
1519 old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1521 audit_log_common_recv_msg(audit_context(), &ab,
1522 AUDIT_CONFIG_CHANGE);
1523 audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
1524 " old-log_passwd=%d new-log_passwd=%d res=%d",
1525 old.enabled, s.enabled, old.log_passwd,
1526 s.log_passwd, !err);
1535 return err < 0 ? err : 0;
1539 * audit_receive - receive messages from a netlink control socket
1540 * @skb: the message buffer
1542 * Parse the provided skb and deal with any messages that may be present,
1543 * malformed skbs are discarded.
1545 static void audit_receive(struct sk_buff *skb)
1547 struct nlmsghdr *nlh;
1550 * len MUST be signed for nlmsg_next to be able to dec it below 0
1551 * if the nlmsg_len was not aligned
1556 nlh = nlmsg_hdr(skb);
1560 while (nlmsg_ok(nlh, len)) {
1561 ack = nlh->nlmsg_flags & NLM_F_ACK;
1562 err = audit_receive_msg(skb, nlh, &ack);
1564 /* send an ack if the user asked for one and audit_receive_msg
1565 * didn't already do it, or if there was an error. */
1567 netlink_ack(skb, nlh, err, NULL);
1569 nlh = nlmsg_next(nlh, &len);
1573 /* can't block with the ctrl lock, so penalize the sender now */
1574 if (audit_backlog_limit &&
1575 (skb_queue_len(&audit_queue) > audit_backlog_limit)) {
1576 DECLARE_WAITQUEUE(wait, current);
1578 /* wake kauditd to try and flush the queue */
1579 wake_up_interruptible(&kauditd_wait);
1581 add_wait_queue_exclusive(&audit_backlog_wait, &wait);
1582 set_current_state(TASK_UNINTERRUPTIBLE);
1583 schedule_timeout(audit_backlog_wait_time);
1584 remove_wait_queue(&audit_backlog_wait, &wait);
1588 /* Run custom bind function on netlink socket group connect or bind requests. */
1589 static int audit_bind(struct net *net, int group)
1591 if (!capable(CAP_AUDIT_READ))
1597 static int __net_init audit_net_init(struct net *net)
1599 struct netlink_kernel_cfg cfg = {
1600 .input = audit_receive,
1602 .flags = NL_CFG_F_NONROOT_RECV,
1603 .groups = AUDIT_NLGRP_MAX,
1606 struct audit_net *aunet = net_generic(net, audit_net_id);
1608 aunet->sk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
1609 if (aunet->sk == NULL) {
1610 audit_panic("cannot initialize netlink socket in namespace");
1613 /* limit the timeout in case auditd is blocked/stopped */
1614 aunet->sk->sk_sndtimeo = HZ / 10;
1619 static void __net_exit audit_net_exit(struct net *net)
1621 struct audit_net *aunet = net_generic(net, audit_net_id);
1623 /* NOTE: you would think that we would want to check the auditd
1624 * connection and potentially reset it here if it lives in this
1625 * namespace, but since the auditd connection tracking struct holds a
1626 * reference to this namespace (see auditd_set()) we are only ever
1627 * going to get here after that connection has been released */
1629 netlink_kernel_release(aunet->sk);
1632 static struct pernet_operations audit_net_ops __net_initdata = {
1633 .init = audit_net_init,
1634 .exit = audit_net_exit,
1635 .id = &audit_net_id,
1636 .size = sizeof(struct audit_net),
1639 /* Initialize audit support at boot time. */
1640 static int __init audit_init(void)
1644 if (audit_initialized == AUDIT_DISABLED)
1647 audit_buffer_cache = kmem_cache_create("audit_buffer",
1648 sizeof(struct audit_buffer),
1649 0, SLAB_PANIC, NULL);
1651 skb_queue_head_init(&audit_queue);
1652 skb_queue_head_init(&audit_retry_queue);
1653 skb_queue_head_init(&audit_hold_queue);
1655 for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
1656 INIT_LIST_HEAD(&audit_inode_hash[i]);
1658 mutex_init(&audit_cmd_mutex.lock);
1659 audit_cmd_mutex.owner = NULL;
1661 pr_info("initializing netlink subsys (%s)\n",
1662 audit_default ? "enabled" : "disabled");
1663 register_pernet_subsys(&audit_net_ops);
1665 audit_initialized = AUDIT_INITIALIZED;
1667 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
1668 if (IS_ERR(kauditd_task)) {
1669 int err = PTR_ERR(kauditd_task);
1670 panic("audit: failed to start the kauditd thread (%d)\n", err);
1673 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL,
1674 "state=initialized audit_enabled=%u res=1",
1679 postcore_initcall(audit_init);
1682 * Process kernel command-line parameter at boot time.
1683 * audit={0|off} or audit={1|on}.
1685 static int __init audit_enable(char *str)
1687 if (!strcasecmp(str, "off") || !strcmp(str, "0"))
1688 audit_default = AUDIT_OFF;
1689 else if (!strcasecmp(str, "on") || !strcmp(str, "1"))
1690 audit_default = AUDIT_ON;
1692 pr_err("audit: invalid 'audit' parameter value (%s)\n", str);
1693 audit_default = AUDIT_ON;
1696 if (audit_default == AUDIT_OFF)
1697 audit_initialized = AUDIT_DISABLED;
1698 if (audit_set_enabled(audit_default))
1699 pr_err("audit: error setting audit state (%d)\n",
1702 pr_info("%s\n", audit_default ?
1703 "enabled (after initialization)" : "disabled (until reboot)");
1707 __setup("audit=", audit_enable);
1709 /* Process kernel command-line parameter at boot time.
1710 * audit_backlog_limit=<n> */
1711 static int __init audit_backlog_limit_set(char *str)
1713 u32 audit_backlog_limit_arg;
1715 pr_info("audit_backlog_limit: ");
1716 if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
1717 pr_cont("using default of %u, unable to parse %s\n",
1718 audit_backlog_limit, str);
1722 audit_backlog_limit = audit_backlog_limit_arg;
1723 pr_cont("%d\n", audit_backlog_limit);
1727 __setup("audit_backlog_limit=", audit_backlog_limit_set);
1729 static void audit_buffer_free(struct audit_buffer *ab)
1735 kmem_cache_free(audit_buffer_cache, ab);
1738 static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx,
1739 gfp_t gfp_mask, int type)
1741 struct audit_buffer *ab;
1743 ab = kmem_cache_alloc(audit_buffer_cache, gfp_mask);
1747 ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
1750 if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0))
1754 ab->gfp_mask = gfp_mask;
1759 audit_buffer_free(ab);
1764 * audit_serial - compute a serial number for the audit record
1766 * Compute a serial number for the audit record. Audit records are
1767 * written to user-space as soon as they are generated, so a complete
1768 * audit record may be written in several pieces. The timestamp of the
1769 * record and this serial number are used by the user-space tools to
1770 * determine which pieces belong to the same audit record. The
1771 * (timestamp,serial) tuple is unique for each syscall and is live from
1772 * syscall entry to syscall exit.
1774 * NOTE: Another possibility is to store the formatted records off the
1775 * audit context (for those records that have a context), and emit them
1776 * all at syscall exit. However, this could delay the reporting of
1777 * significant errors until syscall exit (or never, if the system
1780 unsigned int audit_serial(void)
1782 static atomic_t serial = ATOMIC_INIT(0);
1784 return atomic_add_return(1, &serial);
1787 static inline void audit_get_stamp(struct audit_context *ctx,
1788 struct timespec64 *t, unsigned int *serial)
1790 if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
1791 ktime_get_coarse_real_ts64(t);
1792 *serial = audit_serial();
1797 * audit_log_start - obtain an audit buffer
1798 * @ctx: audit_context (may be NULL)
1799 * @gfp_mask: type of allocation
1800 * @type: audit message type
1802 * Returns audit_buffer pointer on success or NULL on error.
1804 * Obtain an audit buffer. This routine does locking to obtain the
1805 * audit buffer, but then no locking is required for calls to
1806 * audit_log_*format. If the task (ctx) is a task that is currently in a
1807 * syscall, then the syscall is marked as auditable and an audit record
1808 * will be written at syscall exit. If there is no associated task, then
1809 * task context (ctx) should be NULL.
1811 struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1814 struct audit_buffer *ab;
1815 struct timespec64 t;
1816 unsigned int serial;
1818 if (audit_initialized != AUDIT_INITIALIZED)
1821 if (unlikely(!audit_filter(type, AUDIT_FILTER_EXCLUDE)))
1824 /* NOTE: don't ever fail/sleep on these two conditions:
1825 * 1. auditd generated record - since we need auditd to drain the
1826 * queue; also, when we are checking for auditd, compare PIDs using
1827 * task_tgid_vnr() since auditd_pid is set in audit_receive_msg()
1828 * using a PID anchored in the caller's namespace
1829 * 2. generator holding the audit_cmd_mutex - we don't want to block
1830 * while holding the mutex, although we do penalize the sender
1831 * later in audit_receive() when it is safe to block
1833 if (!(auditd_test_task(current) || audit_ctl_owner_current())) {
1834 long stime = audit_backlog_wait_time;
1836 while (audit_backlog_limit &&
1837 (skb_queue_len(&audit_queue) > audit_backlog_limit)) {
1838 /* wake kauditd to try and flush the queue */
1839 wake_up_interruptible(&kauditd_wait);
1841 /* sleep if we are allowed and we haven't exhausted our
1842 * backlog wait limit */
1843 if (gfpflags_allow_blocking(gfp_mask) && (stime > 0)) {
1844 DECLARE_WAITQUEUE(wait, current);
1846 add_wait_queue_exclusive(&audit_backlog_wait,
1848 set_current_state(TASK_UNINTERRUPTIBLE);
1849 stime = schedule_timeout(stime);
1850 remove_wait_queue(&audit_backlog_wait, &wait);
1852 if (audit_rate_check() && printk_ratelimit())
1853 pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
1854 skb_queue_len(&audit_queue),
1855 audit_backlog_limit);
1856 audit_log_lost("backlog limit exceeded");
1862 ab = audit_buffer_alloc(ctx, gfp_mask, type);
1864 audit_log_lost("out of memory in audit_log_start");
1868 audit_get_stamp(ab->ctx, &t, &serial);
1869 audit_log_format(ab, "audit(%llu.%03lu:%u): ",
1870 (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
1876 * audit_expand - expand skb in the audit buffer
1878 * @extra: space to add at tail of the skb
1880 * Returns 0 (no space) on failed expansion, or available space if
1883 static inline int audit_expand(struct audit_buffer *ab, int extra)
1885 struct sk_buff *skb = ab->skb;
1886 int oldtail = skb_tailroom(skb);
1887 int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1888 int newtail = skb_tailroom(skb);
1891 audit_log_lost("out of memory in audit_expand");
1895 skb->truesize += newtail - oldtail;
1900 * Format an audit message into the audit buffer. If there isn't enough
1901 * room in the audit buffer, more room will be allocated and vsnprint
1902 * will be called a second time. Currently, we assume that a printk
1903 * can't format message larger than 1024 bytes, so we don't either.
1905 static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1909 struct sk_buff *skb;
1917 avail = skb_tailroom(skb);
1919 avail = audit_expand(ab, AUDIT_BUFSIZ);
1923 va_copy(args2, args);
1924 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1926 /* The printk buffer is 1024 bytes long, so if we get
1927 * here and AUDIT_BUFSIZ is at least 1024, then we can
1928 * log everything that printk could have logged. */
1929 avail = audit_expand(ab,
1930 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1933 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1944 * audit_log_format - format a message into the audit buffer.
1946 * @fmt: format string
1947 * @...: optional parameters matching @fmt string
1949 * All the work is done in audit_log_vformat.
1951 void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1957 va_start(args, fmt);
1958 audit_log_vformat(ab, fmt, args);
1963 * audit_log_n_hex - convert a buffer to hex and append it to the audit skb
1964 * @ab: the audit_buffer
1965 * @buf: buffer to convert to hex
1966 * @len: length of @buf to be converted
1968 * No return value; failure to expand is silently ignored.
1970 * This function will take the passed buf and convert it into a string of
1971 * ascii hex digits. The new string is placed onto the skb.
1973 void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
1976 int i, avail, new_len;
1978 struct sk_buff *skb;
1985 avail = skb_tailroom(skb);
1987 if (new_len >= avail) {
1988 /* Round the buffer request up to the next multiple */
1989 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1990 avail = audit_expand(ab, new_len);
1995 ptr = skb_tail_pointer(skb);
1996 for (i = 0; i < len; i++)
1997 ptr = hex_byte_pack_upper(ptr, buf[i]);
1999 skb_put(skb, len << 1); /* new string is twice the old string */
2003 * Format a string of no more than slen characters into the audit buffer,
2004 * enclosed in quote marks.
2006 void audit_log_n_string(struct audit_buffer *ab, const char *string,
2011 struct sk_buff *skb;
2018 avail = skb_tailroom(skb);
2019 new_len = slen + 3; /* enclosing quotes + null terminator */
2020 if (new_len > avail) {
2021 avail = audit_expand(ab, new_len);
2025 ptr = skb_tail_pointer(skb);
2027 memcpy(ptr, string, slen);
2031 skb_put(skb, slen + 2); /* don't include null terminator */
2035 * audit_string_contains_control - does a string need to be logged in hex
2036 * @string: string to be checked
2037 * @len: max length of the string to check
2039 bool audit_string_contains_control(const char *string, size_t len)
2041 const unsigned char *p;
2042 for (p = string; p < (const unsigned char *)string + len; p++) {
2043 if (*p == '"' || *p < 0x21 || *p > 0x7e)
2050 * audit_log_n_untrustedstring - log a string that may contain random characters
2052 * @len: length of string (not including trailing null)
2053 * @string: string to be logged
2055 * This code will escape a string that is passed to it if the string
2056 * contains a control character, unprintable character, double quote mark,
2057 * or a space. Unescaped strings will start and end with a double quote mark.
2058 * Strings that are escaped are printed in hex (2 digits per char).
2060 * The caller specifies the number of characters in the string to log, which may
2061 * or may not be the entire string.
2063 void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
2066 if (audit_string_contains_control(string, len))
2067 audit_log_n_hex(ab, string, len);
2069 audit_log_n_string(ab, string, len);
2073 * audit_log_untrustedstring - log a string that may contain random characters
2075 * @string: string to be logged
2077 * Same as audit_log_n_untrustedstring(), except that strlen is used to
2078 * determine string length.
2080 void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
2082 audit_log_n_untrustedstring(ab, string, strlen(string));
2085 /* This is a helper-function to print the escaped d_path */
2086 void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
2087 const struct path *path)
2092 audit_log_format(ab, "%s", prefix);
2094 /* We will allow 11 spaces for ' (deleted)' to be appended */
2095 pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
2097 audit_log_string(ab, "<no_memory>");
2100 p = d_path(path, pathname, PATH_MAX+11);
2101 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
2102 /* FIXME: can we save some information here? */
2103 audit_log_string(ab, "<too_long>");
2105 audit_log_untrustedstring(ab, p);
2109 void audit_log_session_info(struct audit_buffer *ab)
2111 unsigned int sessionid = audit_get_sessionid(current);
2112 uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
2114 audit_log_format(ab, "auid=%u ses=%u", auid, sessionid);
2117 void audit_log_key(struct audit_buffer *ab, char *key)
2119 audit_log_format(ab, " key=");
2121 audit_log_untrustedstring(ab, key);
2123 audit_log_format(ab, "(null)");
2126 int audit_log_task_context(struct audit_buffer *ab)
2133 security_task_getsecid(current, &sid);
2137 error = security_secid_to_secctx(sid, &ctx, &len);
2139 if (error != -EINVAL)
2144 audit_log_format(ab, " subj=%s", ctx);
2145 security_release_secctx(ctx, len);
2149 audit_panic("error in audit_log_task_context");
2152 EXPORT_SYMBOL(audit_log_task_context);
2154 void audit_log_d_path_exe(struct audit_buffer *ab,
2155 struct mm_struct *mm)
2157 struct file *exe_file;
2162 exe_file = get_mm_exe_file(mm);
2166 audit_log_d_path(ab, " exe=", &exe_file->f_path);
2170 audit_log_format(ab, " exe=(null)");
2173 struct tty_struct *audit_get_tty(void)
2175 struct tty_struct *tty = NULL;
2176 unsigned long flags;
2178 spin_lock_irqsave(¤t->sighand->siglock, flags);
2179 if (current->signal)
2180 tty = tty_kref_get(current->signal->tty);
2181 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
2185 void audit_put_tty(struct tty_struct *tty)
2190 void audit_log_task_info(struct audit_buffer *ab)
2192 const struct cred *cred;
2193 char comm[sizeof(current->comm)];
2194 struct tty_struct *tty;
2199 cred = current_cred();
2200 tty = audit_get_tty();
2201 audit_log_format(ab,
2202 " ppid=%d pid=%d auid=%u uid=%u gid=%u"
2203 " euid=%u suid=%u fsuid=%u"
2204 " egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
2205 task_ppid_nr(current),
2206 task_tgid_nr(current),
2207 from_kuid(&init_user_ns, audit_get_loginuid(current)),
2208 from_kuid(&init_user_ns, cred->uid),
2209 from_kgid(&init_user_ns, cred->gid),
2210 from_kuid(&init_user_ns, cred->euid),
2211 from_kuid(&init_user_ns, cred->suid),
2212 from_kuid(&init_user_ns, cred->fsuid),
2213 from_kgid(&init_user_ns, cred->egid),
2214 from_kgid(&init_user_ns, cred->sgid),
2215 from_kgid(&init_user_ns, cred->fsgid),
2216 tty ? tty_name(tty) : "(none)",
2217 audit_get_sessionid(current));
2219 audit_log_format(ab, " comm=");
2220 audit_log_untrustedstring(ab, get_task_comm(comm, current));
2221 audit_log_d_path_exe(ab, current->mm);
2222 audit_log_task_context(ab);
2224 EXPORT_SYMBOL(audit_log_task_info);
2227 * audit_log_link_denied - report a link restriction denial
2228 * @operation: specific link operation
2230 void audit_log_link_denied(const char *operation)
2232 struct audit_buffer *ab;
2234 if (!audit_enabled || audit_dummy_context())
2237 /* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */
2238 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_ANOM_LINK);
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);