1 /* audit.c -- Auditing support
2 * Gateway between the kernel (e.g., selinux) and the user-space audit daemon.
3 * System-call specific features have moved to auditsc.c
5 * Copyright 2003-2007 Red Hat Inc., Durham, North Carolina.
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 * Written by Rickard E. (Rik) Faith <faith@redhat.com>
24 * Goals: 1) Integrate fully with Security Modules.
25 * 2) Minimal run-time overhead:
26 * a) Minimal when syscall auditing is disabled (audit_enable=0).
27 * b) Small when syscall auditing is enabled and no audit record
28 * is generated (defer as much work as possible to record
30 * i) context is allocated,
31 * ii) names from getname are stored without a copy, and
32 * iii) inode information stored from path_lookup.
33 * 3) Ability to disable syscall auditing at boot time (audit=0).
34 * 4) Usable by other parts of the kernel (if audit_log* is called,
35 * then a syscall record will be generated automatically for the
37 * 5) Netlink interface to user-space.
38 * 6) Support low-overhead kernel-based filtering to minimize the
39 * information that must be passed to user-space.
41 * Audit userspace, documentation, tests, and bug/issue trackers:
42 * https://github.com/linux-audit
45 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
47 #include <linux/file.h>
48 #include <linux/init.h>
49 #include <linux/types.h>
50 #include <linux/atomic.h>
52 #include <linux/export.h>
53 #include <linux/slab.h>
54 #include <linux/err.h>
55 #include <linux/kthread.h>
56 #include <linux/kernel.h>
57 #include <linux/syscalls.h>
58 #include <linux/spinlock.h>
59 #include <linux/rcupdate.h>
60 #include <linux/mutex.h>
61 #include <linux/gfp.h>
62 #include <linux/pid.h>
63 #include <linux/slab.h>
65 #include <linux/audit.h>
68 #include <net/netlink.h>
69 #include <linux/skbuff.h>
70 #ifdef CONFIG_SECURITY
71 #include <linux/security.h>
73 #include <linux/freezer.h>
74 #include <linux/pid_namespace.h>
75 #include <net/netns/generic.h>
79 /* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
80 * (Initialization happens after skb_init is called.) */
81 #define AUDIT_DISABLED -1
82 #define AUDIT_UNINITIALIZED 0
83 #define AUDIT_INITIALIZED 1
84 static int audit_initialized;
86 u32 audit_enabled = AUDIT_OFF;
87 bool audit_ever_enabled = !!AUDIT_OFF;
89 EXPORT_SYMBOL_GPL(audit_enabled);
91 /* Default state when kernel boots without any parameters. */
92 static u32 audit_default = AUDIT_OFF;
94 /* If auditing cannot proceed, audit_failure selects what happens. */
95 static u32 audit_failure = AUDIT_FAIL_PRINTK;
97 /* private audit network namespace index */
98 static unsigned int audit_net_id;
101 * struct audit_net - audit private network namespace data
102 * @sk: communication socket
109 * struct auditd_connection - kernel/auditd connection state
111 * @portid: netlink portid
112 * @net: the associated network namespace
116 * This struct is RCU protected; you must either hold the RCU lock for reading
117 * or the associated spinlock for writing.
119 static struct auditd_connection {
124 } *auditd_conn = NULL;
125 static DEFINE_SPINLOCK(auditd_conn_lock);
127 /* If audit_rate_limit is non-zero, limit the rate of sending audit records
128 * to that number per second. This prevents DoS attacks, but results in
129 * audit records being dropped. */
130 static u32 audit_rate_limit;
132 /* Number of outstanding audit_buffers allowed.
133 * When set to zero, this means unlimited. */
134 static u32 audit_backlog_limit = 64;
135 #define AUDIT_BACKLOG_WAIT_TIME (60 * HZ)
136 static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
138 /* The identity of the user shutting down the audit system. */
139 kuid_t audit_sig_uid = INVALID_UID;
140 pid_t audit_sig_pid = -1;
141 u32 audit_sig_sid = 0;
143 /* Records can be lost in several ways:
144 0) [suppressed in audit_alloc]
145 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
146 2) out of memory in audit_log_move [alloc_skb]
147 3) suppressed due to audit_rate_limit
148 4) suppressed due to audit_backlog_limit
150 static atomic_t audit_lost = ATOMIC_INIT(0);
152 /* Hash for inode-based rules */
153 struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
155 static struct kmem_cache *audit_buffer_cache;
157 /* queue msgs to send via kauditd_task */
158 static struct sk_buff_head audit_queue;
159 /* queue msgs due to temporary unicast send problems */
160 static struct sk_buff_head audit_retry_queue;
161 /* queue msgs waiting for new auditd connection */
162 static struct sk_buff_head audit_hold_queue;
164 /* queue servicing thread */
165 static struct task_struct *kauditd_task;
166 static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
168 /* waitqueue for callers who are blocked on the audit backlog */
169 static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
171 static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION,
176 static char *audit_feature_names[2] = {
177 "only_unset_loginuid",
178 "loginuid_immutable",
182 * struct audit_ctl_mutex - serialize requests from userspace
183 * @lock: the mutex used for locking
184 * @owner: the task which owns the lock
187 * This is the lock struct used to ensure we only process userspace requests
188 * in an orderly fashion. We can't simply use a mutex/lock here because we
189 * need to track lock ownership so we don't end up blocking the lock owner in
190 * audit_log_start() or similar.
192 static struct audit_ctl_mutex {
197 /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
198 * audit records. Since printk uses a 1024 byte buffer, this buffer
199 * should be at least that large. */
200 #define AUDIT_BUFSIZ 1024
202 /* The audit_buffer is used when formatting an audit record. The caller
203 * locks briefly to get the record off the freelist or to allocate the
204 * buffer, and locks briefly to send the buffer to the netlink layer or
205 * to place it on a transmit queue. Multiple audit_buffers can be in
206 * use simultaneously. */
207 struct audit_buffer {
208 struct sk_buff *skb; /* formatted skb ready to send */
209 struct audit_context *ctx; /* NULL or associated context */
220 * auditd_test_task - Check to see if a given task is an audit daemon
221 * @task: the task to check
224 * Return 1 if the task is a registered audit daemon, 0 otherwise.
226 int auditd_test_task(struct task_struct *task)
229 struct auditd_connection *ac;
232 ac = rcu_dereference(auditd_conn);
233 rc = (ac && ac->pid == task_tgid(task) ? 1 : 0);
240 * audit_ctl_lock - Take the audit control lock
242 void audit_ctl_lock(void)
244 mutex_lock(&audit_cmd_mutex.lock);
245 audit_cmd_mutex.owner = current;
249 * audit_ctl_unlock - Drop the audit control lock
251 void audit_ctl_unlock(void)
253 audit_cmd_mutex.owner = NULL;
254 mutex_unlock(&audit_cmd_mutex.lock);
258 * audit_ctl_owner_current - Test to see if the current task owns the lock
261 * Return true if the current task owns the audit control lock, false if it
262 * doesn't own the lock.
264 static bool audit_ctl_owner_current(void)
266 return (current == audit_cmd_mutex.owner);
270 * auditd_pid_vnr - Return the auditd PID relative to the namespace
273 * Returns the PID in relation to the namespace, 0 on failure.
275 static pid_t auditd_pid_vnr(void)
278 const struct auditd_connection *ac;
281 ac = rcu_dereference(auditd_conn);
285 pid = pid_vnr(ac->pid);
292 * audit_get_sk - Return the audit socket for the given network namespace
293 * @net: the destination network namespace
296 * Returns the sock pointer if valid, NULL otherwise. The caller must ensure
297 * that a reference is held for the network namespace while the sock is in use.
299 static struct sock *audit_get_sk(const struct net *net)
301 struct audit_net *aunet;
306 aunet = net_generic(net, audit_net_id);
310 void audit_panic(const char *message)
312 switch (audit_failure) {
313 case AUDIT_FAIL_SILENT:
315 case AUDIT_FAIL_PRINTK:
316 if (printk_ratelimit())
317 pr_err("%s\n", message);
319 case AUDIT_FAIL_PANIC:
320 panic("audit: %s\n", message);
325 static inline int audit_rate_check(void)
327 static unsigned long last_check = 0;
328 static int messages = 0;
329 static DEFINE_SPINLOCK(lock);
332 unsigned long elapsed;
335 if (!audit_rate_limit) return 1;
337 spin_lock_irqsave(&lock, flags);
338 if (++messages < audit_rate_limit) {
342 elapsed = now - last_check;
349 spin_unlock_irqrestore(&lock, flags);
355 * audit_log_lost - conditionally log lost audit message event
356 * @message: the message stating reason for lost audit message
358 * Emit at least 1 message per second, even if audit_rate_check is
360 * Always increment the lost messages counter.
362 void audit_log_lost(const char *message)
364 static unsigned long last_msg = 0;
365 static DEFINE_SPINLOCK(lock);
370 atomic_inc(&audit_lost);
372 print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
375 spin_lock_irqsave(&lock, flags);
377 if (now - last_msg > HZ) {
381 spin_unlock_irqrestore(&lock, flags);
385 if (printk_ratelimit())
386 pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
387 atomic_read(&audit_lost),
389 audit_backlog_limit);
390 audit_panic(message);
394 static int audit_log_config_change(char *function_name, u32 new, u32 old,
397 struct audit_buffer *ab;
400 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
403 audit_log_format(ab, "%s=%u old=%u", function_name, new, old);
404 audit_log_session_info(ab);
405 rc = audit_log_task_context(ab);
407 allow_changes = 0; /* Something weird, deny request */
408 audit_log_format(ab, " res=%d", allow_changes);
413 static int audit_do_config_change(char *function_name, u32 *to_change, u32 new)
415 int allow_changes, rc = 0;
416 u32 old = *to_change;
418 /* check if we are locked */
419 if (audit_enabled == AUDIT_LOCKED)
424 if (audit_enabled != AUDIT_OFF) {
425 rc = audit_log_config_change(function_name, new, old, allow_changes);
430 /* If we are allowed, make the change */
431 if (allow_changes == 1)
433 /* Not allowed, update reason */
439 static int audit_set_rate_limit(u32 limit)
441 return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit);
444 static int audit_set_backlog_limit(u32 limit)
446 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit);
449 static int audit_set_backlog_wait_time(u32 timeout)
451 return audit_do_config_change("audit_backlog_wait_time",
452 &audit_backlog_wait_time, timeout);
455 static int audit_set_enabled(u32 state)
458 if (state > AUDIT_LOCKED)
461 rc = audit_do_config_change("audit_enabled", &audit_enabled, state);
463 audit_ever_enabled |= !!state;
468 static int audit_set_failure(u32 state)
470 if (state != AUDIT_FAIL_SILENT
471 && state != AUDIT_FAIL_PRINTK
472 && state != AUDIT_FAIL_PANIC)
475 return audit_do_config_change("audit_failure", &audit_failure, state);
479 * auditd_conn_free - RCU helper to release an auditd connection struct
483 * Drop any references inside the auditd connection tracking struct and free
486 static void auditd_conn_free(struct rcu_head *rcu)
488 struct auditd_connection *ac;
490 ac = container_of(rcu, struct auditd_connection, rcu);
497 * auditd_set - Set/Reset the auditd connection state
499 * @portid: auditd netlink portid
500 * @net: auditd network namespace pointer
503 * This function will obtain and drop network namespace references as
504 * necessary. Returns zero on success, negative values on failure.
506 static int auditd_set(struct pid *pid, u32 portid, struct net *net)
509 struct auditd_connection *ac_old, *ac_new;
514 ac_new = kzalloc(sizeof(*ac_new), GFP_KERNEL);
517 ac_new->pid = get_pid(pid);
518 ac_new->portid = portid;
519 ac_new->net = get_net(net);
521 spin_lock_irqsave(&auditd_conn_lock, flags);
522 ac_old = rcu_dereference_protected(auditd_conn,
523 lockdep_is_held(&auditd_conn_lock));
524 rcu_assign_pointer(auditd_conn, ac_new);
525 spin_unlock_irqrestore(&auditd_conn_lock, flags);
528 call_rcu(&ac_old->rcu, auditd_conn_free);
534 * kauditd_print_skb - Print the audit record to the ring buffer
537 * Whatever the reason, this packet may not make it to the auditd connection
538 * so write it via printk so the information isn't completely lost.
540 static void kauditd_printk_skb(struct sk_buff *skb)
542 struct nlmsghdr *nlh = nlmsg_hdr(skb);
543 char *data = nlmsg_data(nlh);
545 if (nlh->nlmsg_type != AUDIT_EOE && printk_ratelimit())
546 pr_notice("type=%d %s\n", nlh->nlmsg_type, data);
550 * kauditd_rehold_skb - Handle a audit record send failure in the hold queue
552 * @error: error code (unused)
555 * This should only be used by the kauditd_thread when it fails to flush the
558 static void kauditd_rehold_skb(struct sk_buff *skb, __always_unused int error)
560 /* put the record back in the queue */
561 skb_queue_tail(&audit_hold_queue, skb);
565 * kauditd_hold_skb - Queue an audit record, waiting for auditd
570 * Queue the audit record, waiting for an instance of auditd. When this
571 * function is called we haven't given up yet on sending the record, but things
572 * are not looking good. The first thing we want to do is try to write the
573 * record via printk and then see if we want to try and hold on to the record
574 * and queue it, if we have room. If we want to hold on to the record, but we
575 * don't have room, record a record lost message.
577 static void kauditd_hold_skb(struct sk_buff *skb, int error)
579 /* at this point it is uncertain if we will ever send this to auditd so
580 * try to send the message via printk before we go any further */
581 kauditd_printk_skb(skb);
583 /* can we just silently drop the message? */
587 /* the hold queue is only for when the daemon goes away completely,
588 * not -EAGAIN failures; if we are in a -EAGAIN state requeue the
589 * record on the retry queue unless it's full, in which case drop it
591 if (error == -EAGAIN) {
592 if (!audit_backlog_limit ||
593 skb_queue_len(&audit_retry_queue) < audit_backlog_limit) {
594 skb_queue_tail(&audit_retry_queue, skb);
597 audit_log_lost("kauditd retry queue overflow");
601 /* if we have room in the hold queue, queue the message */
602 if (!audit_backlog_limit ||
603 skb_queue_len(&audit_hold_queue) < audit_backlog_limit) {
604 skb_queue_tail(&audit_hold_queue, skb);
608 /* we have no other options - drop the message */
609 audit_log_lost("kauditd hold queue overflow");
615 * kauditd_retry_skb - Queue an audit record, attempt to send again to auditd
617 * @error: error code (unused)
620 * Not as serious as kauditd_hold_skb() as we still have a connected auditd,
621 * but for some reason we are having problems sending it audit records so
622 * queue the given record and attempt to resend.
624 static void kauditd_retry_skb(struct sk_buff *skb, __always_unused int error)
626 if (!audit_backlog_limit ||
627 skb_queue_len(&audit_retry_queue) < audit_backlog_limit) {
628 skb_queue_tail(&audit_retry_queue, skb);
632 /* we have to drop the record, send it via printk as a last effort */
633 kauditd_printk_skb(skb);
634 audit_log_lost("kauditd retry queue overflow");
639 * auditd_reset - Disconnect the auditd connection
640 * @ac: auditd connection state
643 * Break the auditd/kauditd connection and move all the queued records into the
644 * hold queue in case auditd reconnects. It is important to note that the @ac
645 * pointer should never be dereferenced inside this function as it may be NULL
646 * or invalid, you can only compare the memory address! If @ac is NULL then
647 * the connection will always be reset.
649 static void auditd_reset(const struct auditd_connection *ac)
653 struct auditd_connection *ac_old;
655 /* if it isn't already broken, break the connection */
656 spin_lock_irqsave(&auditd_conn_lock, flags);
657 ac_old = rcu_dereference_protected(auditd_conn,
658 lockdep_is_held(&auditd_conn_lock));
659 if (ac && ac != ac_old) {
660 /* someone already registered a new auditd connection */
661 spin_unlock_irqrestore(&auditd_conn_lock, flags);
664 rcu_assign_pointer(auditd_conn, NULL);
665 spin_unlock_irqrestore(&auditd_conn_lock, flags);
668 call_rcu(&ac_old->rcu, auditd_conn_free);
670 /* flush the retry queue to the hold queue, but don't touch the main
671 * queue since we need to process that normally for multicast */
672 while ((skb = skb_dequeue(&audit_retry_queue)))
673 kauditd_hold_skb(skb, -ECONNREFUSED);
677 * auditd_send_unicast_skb - Send a record via unicast to auditd
681 * Send a skb to the audit daemon, returns positive/zero values on success and
682 * negative values on failure; in all cases the skb will be consumed by this
683 * function. If the send results in -ECONNREFUSED the connection with auditd
684 * will be reset. This function may sleep so callers should not hold any locks
685 * where this would cause a problem.
687 static int auditd_send_unicast_skb(struct sk_buff *skb)
693 struct auditd_connection *ac;
695 /* NOTE: we can't call netlink_unicast while in the RCU section so
696 * take a reference to the network namespace and grab local
697 * copies of the namespace, the sock, and the portid; the
698 * namespace and sock aren't going to go away while we hold a
699 * reference and if the portid does become invalid after the RCU
700 * section netlink_unicast() should safely return an error */
703 ac = rcu_dereference(auditd_conn);
710 net = get_net(ac->net);
711 sk = audit_get_sk(net);
715 rc = netlink_unicast(sk, skb, portid, 0);
723 if (ac && rc == -ECONNREFUSED)
729 * kauditd_send_queue - Helper for kauditd_thread to flush skb queues
730 * @sk: the sending sock
731 * @portid: the netlink destination
732 * @queue: the skb queue to process
733 * @retry_limit: limit on number of netlink unicast failures
734 * @skb_hook: per-skb hook for additional processing
735 * @err_hook: hook called if the skb fails the netlink unicast send
738 * Run through the given queue and attempt to send the audit records to auditd,
739 * returns zero on success, negative values on failure. It is up to the caller
740 * to ensure that the @sk is valid for the duration of this function.
743 static int kauditd_send_queue(struct sock *sk, u32 portid,
744 struct sk_buff_head *queue,
745 unsigned int retry_limit,
746 void (*skb_hook)(struct sk_buff *skb),
747 void (*err_hook)(struct sk_buff *skb, int error))
750 struct sk_buff *skb = NULL;
751 struct sk_buff *skb_tail;
752 unsigned int failed = 0;
754 /* NOTE: kauditd_thread takes care of all our locking, we just use
755 * the netlink info passed to us (e.g. sk and portid) */
757 skb_tail = skb_peek_tail(queue);
758 while ((skb != skb_tail) && (skb = skb_dequeue(queue))) {
759 /* call the skb_hook for each skb we touch */
763 /* can we send to anyone via unicast? */
766 (*err_hook)(skb, -ECONNREFUSED);
771 /* grab an extra skb reference in case of error */
773 rc = netlink_unicast(sk, skb, portid, 0);
775 /* send failed - try a few times unless fatal error */
776 if (++failed >= retry_limit ||
777 rc == -ECONNREFUSED || rc == -EPERM) {
780 (*err_hook)(skb, rc);
783 /* continue to drain the queue */
788 /* skb sent - drop the extra reference and continue */
794 return (rc >= 0 ? 0 : rc);
798 * kauditd_send_multicast_skb - Send a record to any multicast listeners
802 * Write a multicast message to anyone listening in the initial network
803 * namespace. This function doesn't consume an skb as might be expected since
804 * it has to copy it anyways.
806 static void kauditd_send_multicast_skb(struct sk_buff *skb)
808 struct sk_buff *copy;
809 struct sock *sock = audit_get_sk(&init_net);
810 struct nlmsghdr *nlh;
812 /* NOTE: we are not taking an additional reference for init_net since
813 * we don't have to worry about it going away */
815 if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
819 * The seemingly wasteful skb_copy() rather than bumping the refcount
820 * using skb_get() is necessary because non-standard mods are made to
821 * the skb by the original kaudit unicast socket send routine. The
822 * existing auditd daemon assumes this breakage. Fixing this would
823 * require co-ordinating a change in the established protocol between
824 * the kaudit kernel subsystem and the auditd userspace code. There is
825 * no reason for new multicast clients to continue with this
828 copy = skb_copy(skb, GFP_KERNEL);
831 nlh = nlmsg_hdr(copy);
832 nlh->nlmsg_len = skb->len;
834 nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL);
838 * kauditd_thread - Worker thread to send audit records to userspace
841 static int kauditd_thread(void *dummy)
845 struct net *net = NULL;
846 struct sock *sk = NULL;
847 struct auditd_connection *ac;
849 #define UNICAST_RETRIES 5
852 while (!kthread_should_stop()) {
853 /* NOTE: see the lock comments in auditd_send_unicast_skb() */
855 ac = rcu_dereference(auditd_conn);
860 net = get_net(ac->net);
861 sk = audit_get_sk(net);
865 /* attempt to flush the hold queue */
866 rc = kauditd_send_queue(sk, portid,
867 &audit_hold_queue, UNICAST_RETRIES,
868 NULL, kauditd_rehold_skb);
875 /* attempt to flush the retry queue */
876 rc = kauditd_send_queue(sk, portid,
877 &audit_retry_queue, UNICAST_RETRIES,
878 NULL, kauditd_hold_skb);
886 /* process the main queue - do the multicast send and attempt
887 * unicast, dump failed record sends to the retry queue; if
888 * sk == NULL due to previous failures we will just do the
889 * multicast send and move the record to the hold queue */
890 rc = kauditd_send_queue(sk, portid, &audit_queue, 1,
891 kauditd_send_multicast_skb,
893 kauditd_retry_skb : kauditd_hold_skb));
898 /* drop our netns reference, no auditd sends past this line */
904 /* we have processed all the queues so wake everyone */
905 wake_up(&audit_backlog_wait);
907 /* NOTE: we want to wake up if there is anything on the queue,
908 * regardless of if an auditd is connected, as we need to
909 * do the multicast send and rotate records from the
910 * main queue to the retry/hold queues */
911 wait_event_freezable(kauditd_wait,
912 (skb_queue_len(&audit_queue) ? 1 : 0));
918 int audit_send_list_thread(void *_dest)
920 struct audit_netlink_list *dest = _dest;
922 struct sock *sk = audit_get_sk(dest->net);
924 /* wait for parent to finish and send an ACK */
928 while ((skb = __skb_dequeue(&dest->q)) != NULL)
929 netlink_unicast(sk, skb, dest->portid, 0);
937 struct sk_buff *audit_make_reply(int seq, int type, int done,
938 int multi, const void *payload, int size)
941 struct nlmsghdr *nlh;
943 int flags = multi ? NLM_F_MULTI : 0;
944 int t = done ? NLMSG_DONE : type;
946 skb = nlmsg_new(size, GFP_KERNEL);
950 nlh = nlmsg_put(skb, 0, seq, t, size, flags);
953 data = nlmsg_data(nlh);
954 memcpy(data, payload, size);
962 static void audit_free_reply(struct audit_reply *reply)
968 kfree_skb(reply->skb);
974 static int audit_send_reply_thread(void *arg)
976 struct audit_reply *reply = (struct audit_reply *)arg;
981 /* Ignore failure. It'll only happen if the sender goes away,
982 because our timeout is set to infinite. */
983 netlink_unicast(audit_get_sk(reply->net), reply->skb, reply->portid, 0);
985 audit_free_reply(reply);
990 * audit_send_reply - send an audit reply message via netlink
991 * @request_skb: skb of request we are replying to (used to target the reply)
992 * @seq: sequence number
993 * @type: audit message type
994 * @done: done (last) flag
995 * @multi: multi-part message flag
996 * @payload: payload data
997 * @size: payload size
999 * Allocates a skb, builds the netlink message, and sends it to the port id.
1001 static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
1002 int multi, const void *payload, int size)
1004 struct task_struct *tsk;
1005 struct audit_reply *reply;
1007 reply = kzalloc(sizeof(*reply), GFP_KERNEL);
1011 reply->skb = audit_make_reply(seq, type, done, multi, payload, size);
1014 reply->net = get_net(sock_net(NETLINK_CB(request_skb).sk));
1015 reply->portid = NETLINK_CB(request_skb).portid;
1017 tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
1024 audit_free_reply(reply);
1028 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
1031 static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
1035 /* Only support initial user namespace for now. */
1037 * We return ECONNREFUSED because it tricks userspace into thinking
1038 * that audit was not configured into the kernel. Lots of users
1039 * configure their PAM stack (because that's what the distro does)
1040 * to reject login if unable to send messages to audit. If we return
1041 * ECONNREFUSED the PAM stack thinks the kernel does not have audit
1042 * configured in and will let login proceed. If we return EPERM
1043 * userspace will reject all logins. This should be removed when we
1044 * support non init namespaces!!
1046 if (current_user_ns() != &init_user_ns)
1047 return -ECONNREFUSED;
1056 case AUDIT_GET_FEATURE:
1057 case AUDIT_SET_FEATURE:
1058 case AUDIT_LIST_RULES:
1059 case AUDIT_ADD_RULE:
1060 case AUDIT_DEL_RULE:
1061 case AUDIT_SIGNAL_INFO:
1065 case AUDIT_MAKE_EQUIV:
1066 /* Only support auditd and auditctl in initial pid namespace
1068 if (task_active_pid_ns(current) != &init_pid_ns)
1071 if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
1075 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1076 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1077 if (!netlink_capable(skb, CAP_AUDIT_WRITE))
1080 default: /* bad msg */
1087 static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
1089 uid_t uid = from_kuid(&init_user_ns, current_uid());
1090 pid_t pid = task_tgid_nr(current);
1092 if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
1097 *ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
1100 audit_log_format(*ab, "pid=%d uid=%u", pid, uid);
1101 audit_log_session_info(*ab);
1102 audit_log_task_context(*ab);
1105 int is_audit_feature_set(int i)
1107 return af.features & AUDIT_FEATURE_TO_MASK(i);
1111 static int audit_get_feature(struct sk_buff *skb)
1115 seq = nlmsg_hdr(skb)->nlmsg_seq;
1117 audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af));
1122 static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
1123 u32 old_lock, u32 new_lock, int res)
1125 struct audit_buffer *ab;
1127 if (audit_enabled == AUDIT_OFF)
1129 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_FEATURE_CHANGE);
1132 audit_log_task_info(ab, current);
1133 audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
1134 audit_feature_names[which], !!old_feature, !!new_feature,
1135 !!old_lock, !!new_lock, res);
1139 static int audit_set_feature(struct audit_features *uaf)
1143 BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
1145 /* if there is ever a version 2 we should handle that here */
1147 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1148 u32 feature = AUDIT_FEATURE_TO_MASK(i);
1149 u32 old_feature, new_feature, old_lock, new_lock;
1151 /* if we are not changing this feature, move along */
1152 if (!(feature & uaf->mask))
1155 old_feature = af.features & feature;
1156 new_feature = uaf->features & feature;
1157 new_lock = (uaf->lock | af.lock) & feature;
1158 old_lock = af.lock & feature;
1160 /* are we changing a locked feature? */
1161 if (old_lock && (new_feature != old_feature)) {
1162 audit_log_feature_change(i, old_feature, new_feature,
1163 old_lock, new_lock, 0);
1167 /* nothing invalid, do the changes */
1168 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1169 u32 feature = AUDIT_FEATURE_TO_MASK(i);
1170 u32 old_feature, new_feature, old_lock, new_lock;
1172 /* if we are not changing this feature, move along */
1173 if (!(feature & uaf->mask))
1176 old_feature = af.features & feature;
1177 new_feature = uaf->features & feature;
1178 old_lock = af.lock & feature;
1179 new_lock = (uaf->lock | af.lock) & feature;
1181 if (new_feature != old_feature)
1182 audit_log_feature_change(i, old_feature, new_feature,
1183 old_lock, new_lock, 1);
1186 af.features |= feature;
1188 af.features &= ~feature;
1189 af.lock |= new_lock;
1195 static int audit_replace(struct pid *pid)
1198 struct sk_buff *skb;
1200 pvnr = pid_vnr(pid);
1201 skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pvnr, sizeof(pvnr));
1204 return auditd_send_unicast_skb(skb);
1207 static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
1213 struct audit_buffer *ab;
1214 u16 msg_type = nlh->nlmsg_type;
1215 struct audit_sig_info *sig_data;
1219 err = audit_netlink_ok(skb, msg_type);
1223 seq = nlh->nlmsg_seq;
1224 data = nlmsg_data(nlh);
1225 data_len = nlmsg_len(nlh);
1229 struct audit_status s;
1230 memset(&s, 0, sizeof(s));
1231 s.enabled = audit_enabled;
1232 s.failure = audit_failure;
1233 /* NOTE: use pid_vnr() so the PID is relative to the current
1235 s.pid = auditd_pid_vnr();
1236 s.rate_limit = audit_rate_limit;
1237 s.backlog_limit = audit_backlog_limit;
1238 s.lost = atomic_read(&audit_lost);
1239 s.backlog = skb_queue_len(&audit_queue);
1240 s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL;
1241 s.backlog_wait_time = audit_backlog_wait_time;
1242 audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
1246 struct audit_status s;
1247 memset(&s, 0, sizeof(s));
1248 /* guard against past and future API changes */
1249 memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
1250 if (s.mask & AUDIT_STATUS_ENABLED) {
1251 err = audit_set_enabled(s.enabled);
1255 if (s.mask & AUDIT_STATUS_FAILURE) {
1256 err = audit_set_failure(s.failure);
1260 if (s.mask & AUDIT_STATUS_PID) {
1261 /* NOTE: we are using the vnr PID functions below
1262 * because the s.pid value is relative to the
1263 * namespace of the caller; at present this
1264 * doesn't matter much since you can really only
1265 * run auditd from the initial pid namespace, but
1266 * something to keep in mind if this changes */
1267 pid_t new_pid = s.pid;
1269 struct pid *req_pid = task_tgid(current);
1271 /* Sanity check - PID values must match. Setting
1272 * pid to 0 is how auditd ends auditing. */
1273 if (new_pid && (new_pid != pid_vnr(req_pid)))
1276 /* test the auditd connection */
1277 audit_replace(req_pid);
1279 auditd_pid = auditd_pid_vnr();
1281 /* replacing a healthy auditd is not allowed */
1283 audit_log_config_change("audit_pid",
1284 new_pid, auditd_pid, 0);
1287 /* only current auditd can unregister itself */
1288 if (pid_vnr(req_pid) != auditd_pid) {
1289 audit_log_config_change("audit_pid",
1290 new_pid, auditd_pid, 0);
1296 /* register a new auditd connection */
1297 err = auditd_set(req_pid,
1298 NETLINK_CB(skb).portid,
1299 sock_net(NETLINK_CB(skb).sk));
1300 if (audit_enabled != AUDIT_OFF)
1301 audit_log_config_change("audit_pid",
1308 /* try to process any backlog */
1309 wake_up_interruptible(&kauditd_wait);
1311 if (audit_enabled != AUDIT_OFF)
1312 audit_log_config_change("audit_pid",
1316 /* unregister the auditd connection */
1320 if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
1321 err = audit_set_rate_limit(s.rate_limit);
1325 if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
1326 err = audit_set_backlog_limit(s.backlog_limit);
1330 if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
1331 if (sizeof(s) > (size_t)nlh->nlmsg_len)
1333 if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
1335 err = audit_set_backlog_wait_time(s.backlog_wait_time);
1339 if (s.mask == AUDIT_STATUS_LOST) {
1340 u32 lost = atomic_xchg(&audit_lost, 0);
1342 audit_log_config_change("lost", 0, lost, 1);
1347 case AUDIT_GET_FEATURE:
1348 err = audit_get_feature(skb);
1352 case AUDIT_SET_FEATURE:
1353 if (data_len < sizeof(struct audit_features))
1355 err = audit_set_feature(data);
1360 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1361 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1362 if (!audit_enabled && msg_type != AUDIT_USER_AVC)
1364 /* exit early if there isn't at least one character to print */
1368 err = audit_filter(msg_type, AUDIT_FILTER_USER);
1369 if (err == 1) { /* match or error */
1373 if (msg_type == AUDIT_USER_TTY) {
1374 err = tty_audit_push();
1378 audit_log_common_recv_msg(&ab, msg_type);
1379 if (msg_type != AUDIT_USER_TTY) {
1380 /* ensure NULL termination */
1381 str[data_len - 1] = '\0';
1382 audit_log_format(ab, " msg='%.*s'",
1383 AUDIT_MESSAGE_TEXT_MAX,
1386 audit_log_format(ab, " data=");
1387 if (data_len > 0 && str[data_len - 1] == '\0')
1389 audit_log_n_untrustedstring(ab, str, data_len);
1394 case AUDIT_ADD_RULE:
1395 case AUDIT_DEL_RULE:
1396 if (data_len < sizeof(struct audit_rule_data))
1398 if (audit_enabled == AUDIT_LOCKED) {
1399 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1400 audit_log_format(ab, " audit_enabled=%d res=0", audit_enabled);
1404 err = audit_rule_change(msg_type, seq, data, data_len);
1406 case AUDIT_LIST_RULES:
1407 err = audit_list_rules_send(skb, seq);
1411 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1412 audit_log_format(ab, " op=trim res=1");
1415 case AUDIT_MAKE_EQUIV: {
1418 size_t msglen = data_len;
1422 if (msglen < 2 * sizeof(u32))
1424 memcpy(sizes, bufp, 2 * sizeof(u32));
1425 bufp += 2 * sizeof(u32);
1426 msglen -= 2 * sizeof(u32);
1427 old = audit_unpack_string(&bufp, &msglen, sizes[0]);
1432 new = audit_unpack_string(&bufp, &msglen, sizes[1]);
1438 /* OK, here comes... */
1439 err = audit_tag_tree(old, new);
1441 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1443 audit_log_format(ab, " op=make_equiv old=");
1444 audit_log_untrustedstring(ab, old);
1445 audit_log_format(ab, " new=");
1446 audit_log_untrustedstring(ab, new);
1447 audit_log_format(ab, " res=%d", !err);
1453 case AUDIT_SIGNAL_INFO:
1455 if (audit_sig_sid) {
1456 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
1460 sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
1463 security_release_secctx(ctx, len);
1466 sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
1467 sig_data->pid = audit_sig_pid;
1468 if (audit_sig_sid) {
1469 memcpy(sig_data->ctx, ctx, len);
1470 security_release_secctx(ctx, len);
1472 audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
1473 sig_data, sizeof(*sig_data) + len);
1476 case AUDIT_TTY_GET: {
1477 struct audit_tty_status s;
1480 t = READ_ONCE(current->signal->audit_tty);
1481 s.enabled = t & AUDIT_TTY_ENABLE;
1482 s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1484 audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
1487 case AUDIT_TTY_SET: {
1488 struct audit_tty_status s, old;
1489 struct audit_buffer *ab;
1492 memset(&s, 0, sizeof(s));
1493 /* guard against past and future API changes */
1494 memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
1495 /* check if new data is valid */
1496 if ((s.enabled != 0 && s.enabled != 1) ||
1497 (s.log_passwd != 0 && s.log_passwd != 1))
1501 t = READ_ONCE(current->signal->audit_tty);
1503 t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD);
1504 t = xchg(¤t->signal->audit_tty, t);
1506 old.enabled = t & AUDIT_TTY_ENABLE;
1507 old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1509 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1510 audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
1511 " old-log_passwd=%d new-log_passwd=%d res=%d",
1512 old.enabled, s.enabled, old.log_passwd,
1513 s.log_passwd, !err);
1522 return err < 0 ? err : 0;
1526 * audit_receive - receive messages from a netlink control socket
1527 * @skb: the message buffer
1529 * Parse the provided skb and deal with any messages that may be present,
1530 * malformed skbs are discarded.
1532 static void audit_receive(struct sk_buff *skb)
1534 struct nlmsghdr *nlh;
1536 * len MUST be signed for nlmsg_next to be able to dec it below 0
1537 * if the nlmsg_len was not aligned
1542 nlh = nlmsg_hdr(skb);
1546 while (nlmsg_ok(nlh, len)) {
1547 err = audit_receive_msg(skb, nlh);
1548 /* if err or if this message says it wants a response */
1549 if (err || (nlh->nlmsg_flags & NLM_F_ACK))
1550 netlink_ack(skb, nlh, err, NULL);
1552 nlh = nlmsg_next(nlh, &len);
1556 /* can't block with the ctrl lock, so penalize the sender now */
1557 if (audit_backlog_limit &&
1558 (skb_queue_len(&audit_queue) > audit_backlog_limit)) {
1559 DECLARE_WAITQUEUE(wait, current);
1561 /* wake kauditd to try and flush the queue */
1562 wake_up_interruptible(&kauditd_wait);
1564 add_wait_queue_exclusive(&audit_backlog_wait, &wait);
1565 set_current_state(TASK_UNINTERRUPTIBLE);
1566 schedule_timeout(audit_backlog_wait_time);
1567 remove_wait_queue(&audit_backlog_wait, &wait);
1571 /* Run custom bind function on netlink socket group connect or bind requests. */
1572 static int audit_bind(struct net *net, int group)
1574 if (!capable(CAP_AUDIT_READ))
1580 static int __net_init audit_net_init(struct net *net)
1582 struct netlink_kernel_cfg cfg = {
1583 .input = audit_receive,
1585 .flags = NL_CFG_F_NONROOT_RECV,
1586 .groups = AUDIT_NLGRP_MAX,
1589 struct audit_net *aunet = net_generic(net, audit_net_id);
1591 aunet->sk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
1592 if (aunet->sk == NULL) {
1593 audit_panic("cannot initialize netlink socket in namespace");
1596 /* limit the timeout in case auditd is blocked/stopped */
1597 aunet->sk->sk_sndtimeo = HZ / 10;
1602 static void __net_exit audit_net_exit(struct net *net)
1604 struct audit_net *aunet = net_generic(net, audit_net_id);
1606 /* NOTE: you would think that we would want to check the auditd
1607 * connection and potentially reset it here if it lives in this
1608 * namespace, but since the auditd connection tracking struct holds a
1609 * reference to this namespace (see auditd_set()) we are only ever
1610 * going to get here after that connection has been released */
1612 netlink_kernel_release(aunet->sk);
1615 static struct pernet_operations audit_net_ops __net_initdata = {
1616 .init = audit_net_init,
1617 .exit = audit_net_exit,
1618 .id = &audit_net_id,
1619 .size = sizeof(struct audit_net),
1622 /* Initialize audit support at boot time. */
1623 static int __init audit_init(void)
1627 if (audit_initialized == AUDIT_DISABLED)
1630 audit_buffer_cache = kmem_cache_create("audit_buffer",
1631 sizeof(struct audit_buffer),
1632 0, SLAB_PANIC, NULL);
1634 skb_queue_head_init(&audit_queue);
1635 skb_queue_head_init(&audit_retry_queue);
1636 skb_queue_head_init(&audit_hold_queue);
1638 for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
1639 INIT_LIST_HEAD(&audit_inode_hash[i]);
1641 mutex_init(&audit_cmd_mutex.lock);
1642 audit_cmd_mutex.owner = NULL;
1644 pr_info("initializing netlink subsys (%s)\n",
1645 audit_default ? "enabled" : "disabled");
1646 register_pernet_subsys(&audit_net_ops);
1648 audit_initialized = AUDIT_INITIALIZED;
1650 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
1651 if (IS_ERR(kauditd_task)) {
1652 int err = PTR_ERR(kauditd_task);
1653 panic("audit: failed to start the kauditd thread (%d)\n", err);
1656 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL,
1657 "state=initialized audit_enabled=%u res=1",
1662 postcore_initcall(audit_init);
1665 * Process kernel command-line parameter at boot time.
1666 * audit={0|off} or audit={1|on}.
1668 static int __init audit_enable(char *str)
1670 if (!strcasecmp(str, "off") || !strcmp(str, "0"))
1671 audit_default = AUDIT_OFF;
1672 else if (!strcasecmp(str, "on") || !strcmp(str, "1"))
1673 audit_default = AUDIT_ON;
1675 pr_err("audit: invalid 'audit' parameter value (%s)\n", str);
1676 audit_default = AUDIT_ON;
1679 if (audit_default == AUDIT_OFF)
1680 audit_initialized = AUDIT_DISABLED;
1681 if (audit_set_enabled(audit_default))
1682 pr_err("audit: error setting audit state (%d)\n",
1685 pr_info("%s\n", audit_default ?
1686 "enabled (after initialization)" : "disabled (until reboot)");
1690 __setup("audit=", audit_enable);
1692 /* Process kernel command-line parameter at boot time.
1693 * audit_backlog_limit=<n> */
1694 static int __init audit_backlog_limit_set(char *str)
1696 u32 audit_backlog_limit_arg;
1698 pr_info("audit_backlog_limit: ");
1699 if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
1700 pr_cont("using default of %u, unable to parse %s\n",
1701 audit_backlog_limit, str);
1705 audit_backlog_limit = audit_backlog_limit_arg;
1706 pr_cont("%d\n", audit_backlog_limit);
1710 __setup("audit_backlog_limit=", audit_backlog_limit_set);
1712 static void audit_buffer_free(struct audit_buffer *ab)
1718 kmem_cache_free(audit_buffer_cache, ab);
1721 static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx,
1722 gfp_t gfp_mask, int type)
1724 struct audit_buffer *ab;
1726 ab = kmem_cache_alloc(audit_buffer_cache, gfp_mask);
1730 ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
1733 if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0))
1737 ab->gfp_mask = gfp_mask;
1742 audit_buffer_free(ab);
1747 * audit_serial - compute a serial number for the audit record
1749 * Compute a serial number for the audit record. Audit records are
1750 * written to user-space as soon as they are generated, so a complete
1751 * audit record may be written in several pieces. The timestamp of the
1752 * record and this serial number are used by the user-space tools to
1753 * determine which pieces belong to the same audit record. The
1754 * (timestamp,serial) tuple is unique for each syscall and is live from
1755 * syscall entry to syscall exit.
1757 * NOTE: Another possibility is to store the formatted records off the
1758 * audit context (for those records that have a context), and emit them
1759 * all at syscall exit. However, this could delay the reporting of
1760 * significant errors until syscall exit (or never, if the system
1763 unsigned int audit_serial(void)
1765 static atomic_t serial = ATOMIC_INIT(0);
1767 return atomic_add_return(1, &serial);
1770 static inline void audit_get_stamp(struct audit_context *ctx,
1771 struct timespec64 *t, unsigned int *serial)
1773 if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
1774 ktime_get_coarse_real_ts64(t);
1775 *serial = audit_serial();
1780 * audit_log_start - obtain an audit buffer
1781 * @ctx: audit_context (may be NULL)
1782 * @gfp_mask: type of allocation
1783 * @type: audit message type
1785 * Returns audit_buffer pointer on success or NULL on error.
1787 * Obtain an audit buffer. This routine does locking to obtain the
1788 * audit buffer, but then no locking is required for calls to
1789 * audit_log_*format. If the task (ctx) is a task that is currently in a
1790 * syscall, then the syscall is marked as auditable and an audit record
1791 * will be written at syscall exit. If there is no associated task, then
1792 * task context (ctx) should be NULL.
1794 struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1797 struct audit_buffer *ab;
1798 struct timespec64 t;
1799 unsigned int uninitialized_var(serial);
1801 if (audit_initialized != AUDIT_INITIALIZED)
1804 if (unlikely(!audit_filter(type, AUDIT_FILTER_EXCLUDE)))
1807 /* NOTE: don't ever fail/sleep on these two conditions:
1808 * 1. auditd generated record - since we need auditd to drain the
1809 * queue; also, when we are checking for auditd, compare PIDs using
1810 * task_tgid_vnr() since auditd_pid is set in audit_receive_msg()
1811 * using a PID anchored in the caller's namespace
1812 * 2. generator holding the audit_cmd_mutex - we don't want to block
1813 * while holding the mutex, although we do penalize the sender
1814 * later in audit_receive() when it is safe to block
1816 if (!(auditd_test_task(current) || audit_ctl_owner_current())) {
1817 long stime = audit_backlog_wait_time;
1819 while (audit_backlog_limit &&
1820 (skb_queue_len(&audit_queue) > audit_backlog_limit)) {
1821 /* wake kauditd to try and flush the queue */
1822 wake_up_interruptible(&kauditd_wait);
1824 /* sleep if we are allowed and we haven't exhausted our
1825 * backlog wait limit */
1826 if (gfpflags_allow_blocking(gfp_mask) && (stime > 0)) {
1827 DECLARE_WAITQUEUE(wait, current);
1829 add_wait_queue_exclusive(&audit_backlog_wait,
1831 set_current_state(TASK_UNINTERRUPTIBLE);
1832 stime = schedule_timeout(stime);
1833 remove_wait_queue(&audit_backlog_wait, &wait);
1835 if (audit_rate_check() && printk_ratelimit())
1836 pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
1837 skb_queue_len(&audit_queue),
1838 audit_backlog_limit);
1839 audit_log_lost("backlog limit exceeded");
1845 ab = audit_buffer_alloc(ctx, gfp_mask, type);
1847 audit_log_lost("out of memory in audit_log_start");
1851 audit_get_stamp(ab->ctx, &t, &serial);
1852 audit_log_format(ab, "audit(%llu.%03lu:%u): ",
1853 (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
1859 * audit_expand - expand skb in the audit buffer
1861 * @extra: space to add at tail of the skb
1863 * Returns 0 (no space) on failed expansion, or available space if
1866 static inline int audit_expand(struct audit_buffer *ab, int extra)
1868 struct sk_buff *skb = ab->skb;
1869 int oldtail = skb_tailroom(skb);
1870 int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1871 int newtail = skb_tailroom(skb);
1874 audit_log_lost("out of memory in audit_expand");
1878 skb->truesize += newtail - oldtail;
1883 * Format an audit message into the audit buffer. If there isn't enough
1884 * room in the audit buffer, more room will be allocated and vsnprint
1885 * will be called a second time. Currently, we assume that a printk
1886 * can't format message larger than 1024 bytes, so we don't either.
1888 static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1892 struct sk_buff *skb;
1900 avail = skb_tailroom(skb);
1902 avail = audit_expand(ab, AUDIT_BUFSIZ);
1906 va_copy(args2, args);
1907 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1909 /* The printk buffer is 1024 bytes long, so if we get
1910 * here and AUDIT_BUFSIZ is at least 1024, then we can
1911 * log everything that printk could have logged. */
1912 avail = audit_expand(ab,
1913 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1916 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1927 * audit_log_format - format a message into the audit buffer.
1929 * @fmt: format string
1930 * @...: optional parameters matching @fmt string
1932 * All the work is done in audit_log_vformat.
1934 void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1940 va_start(args, fmt);
1941 audit_log_vformat(ab, fmt, args);
1946 * audit_log_n_hex - convert a buffer to hex and append it to the audit skb
1947 * @ab: the audit_buffer
1948 * @buf: buffer to convert to hex
1949 * @len: length of @buf to be converted
1951 * No return value; failure to expand is silently ignored.
1953 * This function will take the passed buf and convert it into a string of
1954 * ascii hex digits. The new string is placed onto the skb.
1956 void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
1959 int i, avail, new_len;
1961 struct sk_buff *skb;
1968 avail = skb_tailroom(skb);
1970 if (new_len >= avail) {
1971 /* Round the buffer request up to the next multiple */
1972 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1973 avail = audit_expand(ab, new_len);
1978 ptr = skb_tail_pointer(skb);
1979 for (i = 0; i < len; i++)
1980 ptr = hex_byte_pack_upper(ptr, buf[i]);
1982 skb_put(skb, len << 1); /* new string is twice the old string */
1986 * Format a string of no more than slen characters into the audit buffer,
1987 * enclosed in quote marks.
1989 void audit_log_n_string(struct audit_buffer *ab, const char *string,
1994 struct sk_buff *skb;
2001 avail = skb_tailroom(skb);
2002 new_len = slen + 3; /* enclosing quotes + null terminator */
2003 if (new_len > avail) {
2004 avail = audit_expand(ab, new_len);
2008 ptr = skb_tail_pointer(skb);
2010 memcpy(ptr, string, slen);
2014 skb_put(skb, slen + 2); /* don't include null terminator */
2018 * audit_string_contains_control - does a string need to be logged in hex
2019 * @string: string to be checked
2020 * @len: max length of the string to check
2022 bool audit_string_contains_control(const char *string, size_t len)
2024 const unsigned char *p;
2025 for (p = string; p < (const unsigned char *)string + len; p++) {
2026 if (*p == '"' || *p < 0x21 || *p > 0x7e)
2033 * audit_log_n_untrustedstring - log a string that may contain random characters
2035 * @len: length of string (not including trailing null)
2036 * @string: string to be logged
2038 * This code will escape a string that is passed to it if the string
2039 * contains a control character, unprintable character, double quote mark,
2040 * or a space. Unescaped strings will start and end with a double quote mark.
2041 * Strings that are escaped are printed in hex (2 digits per char).
2043 * The caller specifies the number of characters in the string to log, which may
2044 * or may not be the entire string.
2046 void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
2049 if (audit_string_contains_control(string, len))
2050 audit_log_n_hex(ab, string, len);
2052 audit_log_n_string(ab, string, len);
2056 * audit_log_untrustedstring - log a string that may contain random characters
2058 * @string: string to be logged
2060 * Same as audit_log_n_untrustedstring(), except that strlen is used to
2061 * determine string length.
2063 void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
2065 audit_log_n_untrustedstring(ab, string, strlen(string));
2068 /* This is a helper-function to print the escaped d_path */
2069 void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
2070 const struct path *path)
2075 audit_log_format(ab, "%s", prefix);
2077 /* We will allow 11 spaces for ' (deleted)' to be appended */
2078 pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
2080 audit_log_string(ab, "<no_memory>");
2083 p = d_path(path, pathname, PATH_MAX+11);
2084 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
2085 /* FIXME: can we save some information here? */
2086 audit_log_string(ab, "<too_long>");
2088 audit_log_untrustedstring(ab, p);
2092 void audit_log_session_info(struct audit_buffer *ab)
2094 unsigned int sessionid = audit_get_sessionid(current);
2095 uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
2097 audit_log_format(ab, " auid=%u ses=%u", auid, sessionid);
2100 void audit_log_key(struct audit_buffer *ab, char *key)
2102 audit_log_format(ab, " key=");
2104 audit_log_untrustedstring(ab, key);
2106 audit_log_format(ab, "(null)");
2109 void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap)
2113 audit_log_format(ab, " %s=", prefix);
2114 CAP_FOR_EACH_U32(i) {
2115 audit_log_format(ab, "%08x",
2116 cap->cap[CAP_LAST_U32 - i]);
2120 static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
2122 audit_log_cap(ab, "cap_fp", &name->fcap.permitted);
2123 audit_log_cap(ab, "cap_fi", &name->fcap.inheritable);
2124 audit_log_format(ab, " cap_fe=%d cap_fver=%x",
2125 name->fcap.fE, name->fcap_ver);
2128 static inline int audit_copy_fcaps(struct audit_names *name,
2129 const struct dentry *dentry)
2131 struct cpu_vfs_cap_data caps;
2137 rc = get_vfs_caps_from_disk(dentry, &caps);
2141 name->fcap.permitted = caps.permitted;
2142 name->fcap.inheritable = caps.inheritable;
2143 name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
2144 name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >>
2145 VFS_CAP_REVISION_SHIFT;
2150 /* Copy inode data into an audit_names. */
2151 void audit_copy_inode(struct audit_names *name, const struct dentry *dentry,
2152 struct inode *inode)
2154 name->ino = inode->i_ino;
2155 name->dev = inode->i_sb->s_dev;
2156 name->mode = inode->i_mode;
2157 name->uid = inode->i_uid;
2158 name->gid = inode->i_gid;
2159 name->rdev = inode->i_rdev;
2160 security_inode_getsecid(inode, &name->osid);
2161 audit_copy_fcaps(name, dentry);
2165 * audit_log_name - produce AUDIT_PATH record from struct audit_names
2166 * @context: audit_context for the task
2167 * @n: audit_names structure with reportable details
2168 * @path: optional path to report instead of audit_names->name
2169 * @record_num: record number to report when handling a list of names
2170 * @call_panic: optional pointer to int that will be updated if secid fails
2172 void audit_log_name(struct audit_context *context, struct audit_names *n,
2173 const struct path *path, int record_num, int *call_panic)
2175 struct audit_buffer *ab;
2176 ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH);
2180 audit_log_format(ab, "item=%d", record_num);
2183 audit_log_d_path(ab, " name=", path);
2185 switch (n->name_len) {
2186 case AUDIT_NAME_FULL:
2187 /* log the full path */
2188 audit_log_format(ab, " name=");
2189 audit_log_untrustedstring(ab, n->name->name);
2192 /* name was specified as a relative path and the
2193 * directory component is the cwd */
2194 audit_log_d_path(ab, " name=", &context->pwd);
2197 /* log the name's directory component */
2198 audit_log_format(ab, " name=");
2199 audit_log_n_untrustedstring(ab, n->name->name,
2203 audit_log_format(ab, " name=(null)");
2205 if (n->ino != AUDIT_INO_UNSET)
2206 audit_log_format(ab, " inode=%lu"
2207 " dev=%02x:%02x mode=%#ho"
2208 " ouid=%u ogid=%u rdev=%02x:%02x",
2213 from_kuid(&init_user_ns, n->uid),
2214 from_kgid(&init_user_ns, n->gid),
2220 if (security_secid_to_secctx(
2221 n->osid, &ctx, &len)) {
2222 audit_log_format(ab, " osid=%u", n->osid);
2226 audit_log_format(ab, " obj=%s", ctx);
2227 security_release_secctx(ctx, len);
2231 /* log the audit_names record type */
2232 audit_log_format(ab, " nametype=");
2234 case AUDIT_TYPE_NORMAL:
2235 audit_log_format(ab, "NORMAL");
2237 case AUDIT_TYPE_PARENT:
2238 audit_log_format(ab, "PARENT");
2240 case AUDIT_TYPE_CHILD_DELETE:
2241 audit_log_format(ab, "DELETE");
2243 case AUDIT_TYPE_CHILD_CREATE:
2244 audit_log_format(ab, "CREATE");
2247 audit_log_format(ab, "UNKNOWN");
2251 audit_log_fcaps(ab, n);
2255 int audit_log_task_context(struct audit_buffer *ab)
2262 security_task_getsecid(current, &sid);
2266 error = security_secid_to_secctx(sid, &ctx, &len);
2268 if (error != -EINVAL)
2273 audit_log_format(ab, " subj=%s", ctx);
2274 security_release_secctx(ctx, len);
2278 audit_panic("error in audit_log_task_context");
2281 EXPORT_SYMBOL(audit_log_task_context);
2283 void audit_log_d_path_exe(struct audit_buffer *ab,
2284 struct mm_struct *mm)
2286 struct file *exe_file;
2291 exe_file = get_mm_exe_file(mm);
2295 audit_log_d_path(ab, " exe=", &exe_file->f_path);
2299 audit_log_format(ab, " exe=(null)");
2302 struct tty_struct *audit_get_tty(struct task_struct *tsk)
2304 struct tty_struct *tty = NULL;
2305 unsigned long flags;
2307 spin_lock_irqsave(&tsk->sighand->siglock, flags);
2309 tty = tty_kref_get(tsk->signal->tty);
2310 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
2314 void audit_put_tty(struct tty_struct *tty)
2319 void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
2321 const struct cred *cred;
2322 char comm[sizeof(tsk->comm)];
2323 struct tty_struct *tty;
2328 /* tsk == current */
2329 cred = current_cred();
2330 tty = audit_get_tty(tsk);
2331 audit_log_format(ab,
2332 " ppid=%d pid=%d auid=%u uid=%u gid=%u"
2333 " euid=%u suid=%u fsuid=%u"
2334 " egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
2337 from_kuid(&init_user_ns, audit_get_loginuid(tsk)),
2338 from_kuid(&init_user_ns, cred->uid),
2339 from_kgid(&init_user_ns, cred->gid),
2340 from_kuid(&init_user_ns, cred->euid),
2341 from_kuid(&init_user_ns, cred->suid),
2342 from_kuid(&init_user_ns, cred->fsuid),
2343 from_kgid(&init_user_ns, cred->egid),
2344 from_kgid(&init_user_ns, cred->sgid),
2345 from_kgid(&init_user_ns, cred->fsgid),
2346 tty ? tty_name(tty) : "(none)",
2347 audit_get_sessionid(tsk));
2349 audit_log_format(ab, " comm=");
2350 audit_log_untrustedstring(ab, get_task_comm(comm, tsk));
2351 audit_log_d_path_exe(ab, tsk->mm);
2352 audit_log_task_context(ab);
2354 EXPORT_SYMBOL(audit_log_task_info);
2357 * audit_log_link_denied - report a link restriction denial
2358 * @operation: specific link operation
2360 void audit_log_link_denied(const char *operation)
2362 struct audit_buffer *ab;
2364 if (!audit_enabled || audit_dummy_context())
2367 /* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */
2368 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_ANOM_LINK);
2371 audit_log_format(ab, "op=%s", operation);
2372 audit_log_task_info(ab, current);
2373 audit_log_format(ab, " res=0");
2378 * audit_log_end - end one audit record
2379 * @ab: the audit_buffer
2381 * We can not do a netlink send inside an irq context because it blocks (last
2382 * arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a
2383 * queue and a tasklet is scheduled to remove them from the queue outside the
2384 * irq context. May be called in any context.
2386 void audit_log_end(struct audit_buffer *ab)
2388 struct sk_buff *skb;
2389 struct nlmsghdr *nlh;
2394 if (audit_rate_check()) {
2398 /* setup the netlink header, see the comments in
2399 * kauditd_send_multicast_skb() for length quirks */
2400 nlh = nlmsg_hdr(skb);
2401 nlh->nlmsg_len = skb->len - NLMSG_HDRLEN;
2403 /* queue the netlink packet and poke the kauditd thread */
2404 skb_queue_tail(&audit_queue, skb);
2405 wake_up_interruptible(&kauditd_wait);
2407 audit_log_lost("rate limit exceeded");
2409 audit_buffer_free(ab);
2413 * audit_log - Log an audit record
2414 * @ctx: audit context
2415 * @gfp_mask: type of allocation
2416 * @type: audit message type
2417 * @fmt: format string to use
2418 * @...: variable parameters matching the format string
2420 * This is a convenience function that calls audit_log_start,
2421 * audit_log_vformat, and audit_log_end. It may be called
2424 void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
2425 const char *fmt, ...)
2427 struct audit_buffer *ab;
2430 ab = audit_log_start(ctx, gfp_mask, type);
2432 va_start(args, fmt);
2433 audit_log_vformat(ab, fmt, args);
2439 EXPORT_SYMBOL(audit_log_start);
2440 EXPORT_SYMBOL(audit_log_end);
2441 EXPORT_SYMBOL(audit_log_format);
2442 EXPORT_SYMBOL(audit_log);