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
554 * This should only be used by the kauditd_thread when it fails to flush the
557 static void kauditd_rehold_skb(struct sk_buff *skb)
559 /* put the record back in the queue at the same place */
560 skb_queue_head(&audit_hold_queue, skb);
564 * kauditd_hold_skb - Queue an audit record, waiting for auditd
568 * Queue the audit record, waiting for an instance of auditd. When this
569 * function is called we haven't given up yet on sending the record, but things
570 * are not looking good. The first thing we want to do is try to write the
571 * record via printk and then see if we want to try and hold on to the record
572 * and queue it, if we have room. If we want to hold on to the record, but we
573 * don't have room, record a record lost message.
575 static void kauditd_hold_skb(struct sk_buff *skb)
577 /* at this point it is uncertain if we will ever send this to auditd so
578 * try to send the message via printk before we go any further */
579 kauditd_printk_skb(skb);
581 /* can we just silently drop the message? */
582 if (!audit_default) {
587 /* if we have room, queue the message */
588 if (!audit_backlog_limit ||
589 skb_queue_len(&audit_hold_queue) < audit_backlog_limit) {
590 skb_queue_tail(&audit_hold_queue, skb);
594 /* we have no other options - drop the message */
595 audit_log_lost("kauditd hold queue overflow");
600 * kauditd_retry_skb - Queue an audit record, attempt to send again to auditd
604 * Not as serious as kauditd_hold_skb() as we still have a connected auditd,
605 * but for some reason we are having problems sending it audit records so
606 * queue the given record and attempt to resend.
608 static void kauditd_retry_skb(struct sk_buff *skb)
610 /* NOTE: because records should only live in the retry queue for a
611 * short period of time, before either being sent or moved to the hold
612 * queue, we don't currently enforce a limit on this queue */
613 skb_queue_tail(&audit_retry_queue, skb);
617 * auditd_reset - Disconnect the auditd connection
618 * @ac: auditd connection state
621 * Break the auditd/kauditd connection and move all the queued records into the
622 * hold queue in case auditd reconnects. It is important to note that the @ac
623 * pointer should never be dereferenced inside this function as it may be NULL
624 * or invalid, you can only compare the memory address! If @ac is NULL then
625 * the connection will always be reset.
627 static void auditd_reset(const struct auditd_connection *ac)
631 struct auditd_connection *ac_old;
633 /* if it isn't already broken, break the connection */
634 spin_lock_irqsave(&auditd_conn_lock, flags);
635 ac_old = rcu_dereference_protected(auditd_conn,
636 lockdep_is_held(&auditd_conn_lock));
637 if (ac && ac != ac_old) {
638 /* someone already registered a new auditd connection */
639 spin_unlock_irqrestore(&auditd_conn_lock, flags);
642 rcu_assign_pointer(auditd_conn, NULL);
643 spin_unlock_irqrestore(&auditd_conn_lock, flags);
646 call_rcu(&ac_old->rcu, auditd_conn_free);
648 /* flush the retry queue to the hold queue, but don't touch the main
649 * queue since we need to process that normally for multicast */
650 while ((skb = skb_dequeue(&audit_retry_queue)))
651 kauditd_hold_skb(skb);
655 * auditd_send_unicast_skb - Send a record via unicast to auditd
659 * Send a skb to the audit daemon, returns positive/zero values on success and
660 * negative values on failure; in all cases the skb will be consumed by this
661 * function. If the send results in -ECONNREFUSED the connection with auditd
662 * will be reset. This function may sleep so callers should not hold any locks
663 * where this would cause a problem.
665 static int auditd_send_unicast_skb(struct sk_buff *skb)
671 struct auditd_connection *ac;
673 /* NOTE: we can't call netlink_unicast while in the RCU section so
674 * take a reference to the network namespace and grab local
675 * copies of the namespace, the sock, and the portid; the
676 * namespace and sock aren't going to go away while we hold a
677 * reference and if the portid does become invalid after the RCU
678 * section netlink_unicast() should safely return an error */
681 ac = rcu_dereference(auditd_conn);
688 net = get_net(ac->net);
689 sk = audit_get_sk(net);
693 rc = netlink_unicast(sk, skb, portid, 0);
701 if (ac && rc == -ECONNREFUSED)
707 * kauditd_send_queue - Helper for kauditd_thread to flush skb queues
708 * @sk: the sending sock
709 * @portid: the netlink destination
710 * @queue: the skb queue to process
711 * @retry_limit: limit on number of netlink unicast failures
712 * @skb_hook: per-skb hook for additional processing
713 * @err_hook: hook called if the skb fails the netlink unicast send
716 * Run through the given queue and attempt to send the audit records to auditd,
717 * returns zero on success, negative values on failure. It is up to the caller
718 * to ensure that the @sk is valid for the duration of this function.
721 static int kauditd_send_queue(struct sock *sk, u32 portid,
722 struct sk_buff_head *queue,
723 unsigned int retry_limit,
724 void (*skb_hook)(struct sk_buff *skb),
725 void (*err_hook)(struct sk_buff *skb))
729 static unsigned int failed = 0;
731 /* NOTE: kauditd_thread takes care of all our locking, we just use
732 * the netlink info passed to us (e.g. sk and portid) */
734 while ((skb = skb_dequeue(queue))) {
735 /* call the skb_hook for each skb we touch */
739 /* can we send to anyone via unicast? */
746 /* grab an extra skb reference in case of error */
748 rc = netlink_unicast(sk, skb, portid, 0);
750 /* fatal failure for our queue flush attempt? */
751 if (++failed >= retry_limit ||
752 rc == -ECONNREFUSED || rc == -EPERM) {
753 /* yes - error processing for the queue */
759 /* keep processing with the skb_hook */
762 /* no - requeue to preserve ordering */
763 skb_queue_head(queue, skb);
765 /* it worked - drop the extra reference and continue */
772 return (rc >= 0 ? 0 : rc);
776 * kauditd_send_multicast_skb - Send a record to any multicast listeners
780 * Write a multicast message to anyone listening in the initial network
781 * namespace. This function doesn't consume an skb as might be expected since
782 * it has to copy it anyways.
784 static void kauditd_send_multicast_skb(struct sk_buff *skb)
786 struct sk_buff *copy;
787 struct sock *sock = audit_get_sk(&init_net);
788 struct nlmsghdr *nlh;
790 /* NOTE: we are not taking an additional reference for init_net since
791 * we don't have to worry about it going away */
793 if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
797 * The seemingly wasteful skb_copy() rather than bumping the refcount
798 * using skb_get() is necessary because non-standard mods are made to
799 * the skb by the original kaudit unicast socket send routine. The
800 * existing auditd daemon assumes this breakage. Fixing this would
801 * require co-ordinating a change in the established protocol between
802 * the kaudit kernel subsystem and the auditd userspace code. There is
803 * no reason for new multicast clients to continue with this
806 copy = skb_copy(skb, GFP_KERNEL);
809 nlh = nlmsg_hdr(copy);
810 nlh->nlmsg_len = skb->len;
812 nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL);
816 * kauditd_thread - Worker thread to send audit records to userspace
819 static int kauditd_thread(void *dummy)
823 struct net *net = NULL;
824 struct sock *sk = NULL;
825 struct auditd_connection *ac;
827 #define UNICAST_RETRIES 5
830 while (!kthread_should_stop()) {
831 /* NOTE: see the lock comments in auditd_send_unicast_skb() */
833 ac = rcu_dereference(auditd_conn);
838 net = get_net(ac->net);
839 sk = audit_get_sk(net);
843 /* attempt to flush the hold queue */
844 rc = kauditd_send_queue(sk, portid,
845 &audit_hold_queue, UNICAST_RETRIES,
846 NULL, kauditd_rehold_skb);
853 /* attempt to flush the retry queue */
854 rc = kauditd_send_queue(sk, portid,
855 &audit_retry_queue, UNICAST_RETRIES,
856 NULL, kauditd_hold_skb);
864 /* process the main queue - do the multicast send and attempt
865 * unicast, dump failed record sends to the retry queue; if
866 * sk == NULL due to previous failures we will just do the
867 * multicast send and move the record to the hold queue */
868 rc = kauditd_send_queue(sk, portid, &audit_queue, 1,
869 kauditd_send_multicast_skb,
871 kauditd_retry_skb : kauditd_hold_skb));
876 /* drop our netns reference, no auditd sends past this line */
882 /* we have processed all the queues so wake everyone */
883 wake_up(&audit_backlog_wait);
885 /* NOTE: we want to wake up if there is anything on the queue,
886 * regardless of if an auditd is connected, as we need to
887 * do the multicast send and rotate records from the
888 * main queue to the retry/hold queues */
889 wait_event_freezable(kauditd_wait,
890 (skb_queue_len(&audit_queue) ? 1 : 0));
896 int audit_send_list(void *_dest)
898 struct audit_netlink_list *dest = _dest;
900 struct sock *sk = audit_get_sk(dest->net);
902 /* wait for parent to finish and send an ACK */
906 while ((skb = __skb_dequeue(&dest->q)) != NULL)
907 netlink_unicast(sk, skb, dest->portid, 0);
915 struct sk_buff *audit_make_reply(int seq, int type, int done,
916 int multi, const void *payload, int size)
919 struct nlmsghdr *nlh;
921 int flags = multi ? NLM_F_MULTI : 0;
922 int t = done ? NLMSG_DONE : type;
924 skb = nlmsg_new(size, GFP_KERNEL);
928 nlh = nlmsg_put(skb, 0, seq, t, size, flags);
931 data = nlmsg_data(nlh);
932 memcpy(data, payload, size);
940 static int audit_send_reply_thread(void *arg)
942 struct audit_reply *reply = (struct audit_reply *)arg;
943 struct sock *sk = audit_get_sk(reply->net);
948 /* Ignore failure. It'll only happen if the sender goes away,
949 because our timeout is set to infinite. */
950 netlink_unicast(sk, reply->skb, reply->portid, 0);
957 * audit_send_reply - send an audit reply message via netlink
958 * @request_skb: skb of request we are replying to (used to target the reply)
959 * @seq: sequence number
960 * @type: audit message type
961 * @done: done (last) flag
962 * @multi: multi-part message flag
963 * @payload: payload data
964 * @size: payload size
966 * Allocates an skb, builds the netlink message, and sends it to the port id.
967 * No failure notifications.
969 static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
970 int multi, const void *payload, int size)
972 struct net *net = sock_net(NETLINK_CB(request_skb).sk);
974 struct task_struct *tsk;
975 struct audit_reply *reply = kmalloc(sizeof(struct audit_reply),
981 skb = audit_make_reply(seq, type, done, multi, payload, size);
985 reply->net = get_net(net);
986 reply->portid = NETLINK_CB(request_skb).portid;
989 tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
998 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
1001 static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
1005 /* Only support initial user namespace for now. */
1007 * We return ECONNREFUSED because it tricks userspace into thinking
1008 * that audit was not configured into the kernel. Lots of users
1009 * configure their PAM stack (because that's what the distro does)
1010 * to reject login if unable to send messages to audit. If we return
1011 * ECONNREFUSED the PAM stack thinks the kernel does not have audit
1012 * configured in and will let login proceed. If we return EPERM
1013 * userspace will reject all logins. This should be removed when we
1014 * support non init namespaces!!
1016 if (current_user_ns() != &init_user_ns)
1017 return -ECONNREFUSED;
1026 case AUDIT_GET_FEATURE:
1027 case AUDIT_SET_FEATURE:
1028 case AUDIT_LIST_RULES:
1029 case AUDIT_ADD_RULE:
1030 case AUDIT_DEL_RULE:
1031 case AUDIT_SIGNAL_INFO:
1035 case AUDIT_MAKE_EQUIV:
1036 /* Only support auditd and auditctl in initial pid namespace
1038 if (task_active_pid_ns(current) != &init_pid_ns)
1041 if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
1045 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1046 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1047 if (!netlink_capable(skb, CAP_AUDIT_WRITE))
1050 default: /* bad msg */
1057 static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
1059 uid_t uid = from_kuid(&init_user_ns, current_uid());
1060 pid_t pid = task_tgid_nr(current);
1062 if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
1067 *ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
1070 audit_log_format(*ab, "pid=%d uid=%u ", pid, uid);
1071 audit_log_session_info(*ab);
1072 audit_log_task_context(*ab);
1075 int is_audit_feature_set(int i)
1077 return af.features & AUDIT_FEATURE_TO_MASK(i);
1081 static int audit_get_feature(struct sk_buff *skb)
1085 seq = nlmsg_hdr(skb)->nlmsg_seq;
1087 audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af));
1092 static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
1093 u32 old_lock, u32 new_lock, int res)
1095 struct audit_buffer *ab;
1097 if (audit_enabled == AUDIT_OFF)
1100 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_FEATURE_CHANGE);
1103 audit_log_task_info(ab);
1104 audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
1105 audit_feature_names[which], !!old_feature, !!new_feature,
1106 !!old_lock, !!new_lock, res);
1110 static int audit_set_feature(struct sk_buff *skb)
1112 struct audit_features *uaf;
1115 BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
1116 uaf = nlmsg_data(nlmsg_hdr(skb));
1118 /* if there is ever a version 2 we should handle that here */
1120 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1121 u32 feature = AUDIT_FEATURE_TO_MASK(i);
1122 u32 old_feature, new_feature, old_lock, new_lock;
1124 /* if we are not changing this feature, move along */
1125 if (!(feature & uaf->mask))
1128 old_feature = af.features & feature;
1129 new_feature = uaf->features & feature;
1130 new_lock = (uaf->lock | af.lock) & feature;
1131 old_lock = af.lock & feature;
1133 /* are we changing a locked feature? */
1134 if (old_lock && (new_feature != old_feature)) {
1135 audit_log_feature_change(i, old_feature, new_feature,
1136 old_lock, new_lock, 0);
1140 /* nothing invalid, do the changes */
1141 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1142 u32 feature = AUDIT_FEATURE_TO_MASK(i);
1143 u32 old_feature, new_feature, old_lock, new_lock;
1145 /* if we are not changing this feature, move along */
1146 if (!(feature & uaf->mask))
1149 old_feature = af.features & feature;
1150 new_feature = uaf->features & feature;
1151 old_lock = af.lock & feature;
1152 new_lock = (uaf->lock | af.lock) & feature;
1154 if (new_feature != old_feature)
1155 audit_log_feature_change(i, old_feature, new_feature,
1156 old_lock, new_lock, 1);
1159 af.features |= feature;
1161 af.features &= ~feature;
1162 af.lock |= new_lock;
1168 static int audit_replace(struct pid *pid)
1171 struct sk_buff *skb;
1173 pvnr = pid_vnr(pid);
1174 skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pvnr, sizeof(pvnr));
1177 return auditd_send_unicast_skb(skb);
1180 static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
1185 struct audit_buffer *ab;
1186 u16 msg_type = nlh->nlmsg_type;
1187 struct audit_sig_info *sig_data;
1191 err = audit_netlink_ok(skb, msg_type);
1195 seq = nlh->nlmsg_seq;
1196 data = nlmsg_data(nlh);
1200 struct audit_status s;
1201 memset(&s, 0, sizeof(s));
1202 s.enabled = audit_enabled;
1203 s.failure = audit_failure;
1204 /* NOTE: use pid_vnr() so the PID is relative to the current
1206 s.pid = auditd_pid_vnr();
1207 s.rate_limit = audit_rate_limit;
1208 s.backlog_limit = audit_backlog_limit;
1209 s.lost = atomic_read(&audit_lost);
1210 s.backlog = skb_queue_len(&audit_queue);
1211 s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL;
1212 s.backlog_wait_time = audit_backlog_wait_time;
1213 audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
1217 struct audit_status s;
1218 memset(&s, 0, sizeof(s));
1219 /* guard against past and future API changes */
1220 memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
1221 if (s.mask & AUDIT_STATUS_ENABLED) {
1222 err = audit_set_enabled(s.enabled);
1226 if (s.mask & AUDIT_STATUS_FAILURE) {
1227 err = audit_set_failure(s.failure);
1231 if (s.mask & AUDIT_STATUS_PID) {
1232 /* NOTE: we are using the vnr PID functions below
1233 * because the s.pid value is relative to the
1234 * namespace of the caller; at present this
1235 * doesn't matter much since you can really only
1236 * run auditd from the initial pid namespace, but
1237 * something to keep in mind if this changes */
1238 pid_t new_pid = s.pid;
1240 struct pid *req_pid = task_tgid(current);
1242 /* Sanity check - PID values must match. Setting
1243 * pid to 0 is how auditd ends auditing. */
1244 if (new_pid && (new_pid != pid_vnr(req_pid)))
1247 /* test the auditd connection */
1248 audit_replace(req_pid);
1250 auditd_pid = auditd_pid_vnr();
1252 /* replacing a healthy auditd is not allowed */
1254 audit_log_config_change("audit_pid",
1255 new_pid, auditd_pid, 0);
1258 /* only current auditd can unregister itself */
1259 if (pid_vnr(req_pid) != auditd_pid) {
1260 audit_log_config_change("audit_pid",
1261 new_pid, auditd_pid, 0);
1267 /* register a new auditd connection */
1268 err = auditd_set(req_pid,
1269 NETLINK_CB(skb).portid,
1270 sock_net(NETLINK_CB(skb).sk));
1271 if (audit_enabled != AUDIT_OFF)
1272 audit_log_config_change("audit_pid",
1279 /* try to process any backlog */
1280 wake_up_interruptible(&kauditd_wait);
1282 if (audit_enabled != AUDIT_OFF)
1283 audit_log_config_change("audit_pid",
1287 /* unregister the auditd connection */
1291 if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
1292 err = audit_set_rate_limit(s.rate_limit);
1296 if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
1297 err = audit_set_backlog_limit(s.backlog_limit);
1301 if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
1302 if (sizeof(s) > (size_t)nlh->nlmsg_len)
1304 if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
1306 err = audit_set_backlog_wait_time(s.backlog_wait_time);
1310 if (s.mask == AUDIT_STATUS_LOST) {
1311 u32 lost = atomic_xchg(&audit_lost, 0);
1313 audit_log_config_change("lost", 0, lost, 1);
1318 case AUDIT_GET_FEATURE:
1319 err = audit_get_feature(skb);
1323 case AUDIT_SET_FEATURE:
1324 err = audit_set_feature(skb);
1329 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1330 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1331 if (!audit_enabled && msg_type != AUDIT_USER_AVC)
1334 err = audit_filter(msg_type, AUDIT_FILTER_USER);
1335 if (err == 1) { /* match or error */
1337 if (msg_type == AUDIT_USER_TTY) {
1338 err = tty_audit_push();
1342 audit_log_common_recv_msg(&ab, msg_type);
1343 if (msg_type != AUDIT_USER_TTY)
1344 audit_log_format(ab, " msg='%.*s'",
1345 AUDIT_MESSAGE_TEXT_MAX,
1350 audit_log_format(ab, " data=");
1351 size = nlmsg_len(nlh);
1353 ((unsigned char *)data)[size - 1] == '\0')
1355 audit_log_n_untrustedstring(ab, data, size);
1360 case AUDIT_ADD_RULE:
1361 case AUDIT_DEL_RULE:
1362 if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
1364 if (audit_enabled == AUDIT_LOCKED) {
1365 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1366 audit_log_format(ab, " audit_enabled=%d res=0", audit_enabled);
1370 err = audit_rule_change(msg_type, seq, data, nlmsg_len(nlh));
1372 case AUDIT_LIST_RULES:
1373 err = audit_list_rules_send(skb, seq);
1377 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1378 audit_log_format(ab, " op=trim res=1");
1381 case AUDIT_MAKE_EQUIV: {
1384 size_t msglen = nlmsg_len(nlh);
1388 if (msglen < 2 * sizeof(u32))
1390 memcpy(sizes, bufp, 2 * sizeof(u32));
1391 bufp += 2 * sizeof(u32);
1392 msglen -= 2 * sizeof(u32);
1393 old = audit_unpack_string(&bufp, &msglen, sizes[0]);
1398 new = audit_unpack_string(&bufp, &msglen, sizes[1]);
1404 /* OK, here comes... */
1405 err = audit_tag_tree(old, new);
1407 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1409 audit_log_format(ab, " op=make_equiv old=");
1410 audit_log_untrustedstring(ab, old);
1411 audit_log_format(ab, " new=");
1412 audit_log_untrustedstring(ab, new);
1413 audit_log_format(ab, " res=%d", !err);
1419 case AUDIT_SIGNAL_INFO:
1421 if (audit_sig_sid) {
1422 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
1426 sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
1429 security_release_secctx(ctx, len);
1432 sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
1433 sig_data->pid = audit_sig_pid;
1434 if (audit_sig_sid) {
1435 memcpy(sig_data->ctx, ctx, len);
1436 security_release_secctx(ctx, len);
1438 audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
1439 sig_data, sizeof(*sig_data) + len);
1442 case AUDIT_TTY_GET: {
1443 struct audit_tty_status s;
1446 t = READ_ONCE(current->signal->audit_tty);
1447 s.enabled = t & AUDIT_TTY_ENABLE;
1448 s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1450 audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
1453 case AUDIT_TTY_SET: {
1454 struct audit_tty_status s, old;
1455 struct audit_buffer *ab;
1458 memset(&s, 0, sizeof(s));
1459 /* guard against past and future API changes */
1460 memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
1461 /* check if new data is valid */
1462 if ((s.enabled != 0 && s.enabled != 1) ||
1463 (s.log_passwd != 0 && s.log_passwd != 1))
1467 t = READ_ONCE(current->signal->audit_tty);
1469 t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD);
1470 t = xchg(¤t->signal->audit_tty, t);
1472 old.enabled = t & AUDIT_TTY_ENABLE;
1473 old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1475 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1476 audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
1477 " old-log_passwd=%d new-log_passwd=%d res=%d",
1478 old.enabled, s.enabled, old.log_passwd,
1479 s.log_passwd, !err);
1488 return err < 0 ? err : 0;
1492 * audit_receive - receive messages from a netlink control socket
1493 * @skb: the message buffer
1495 * Parse the provided skb and deal with any messages that may be present,
1496 * malformed skbs are discarded.
1498 static void audit_receive(struct sk_buff *skb)
1500 struct nlmsghdr *nlh;
1502 * len MUST be signed for nlmsg_next to be able to dec it below 0
1503 * if the nlmsg_len was not aligned
1508 nlh = nlmsg_hdr(skb);
1512 while (nlmsg_ok(nlh, len)) {
1513 err = audit_receive_msg(skb, nlh);
1514 /* if err or if this message says it wants a response */
1515 if (err || (nlh->nlmsg_flags & NLM_F_ACK))
1516 netlink_ack(skb, nlh, err, NULL);
1518 nlh = nlmsg_next(nlh, &len);
1523 /* Run custom bind function on netlink socket group connect or bind requests. */
1524 static int audit_bind(struct net *net, int group)
1526 if (!capable(CAP_AUDIT_READ))
1532 static int __net_init audit_net_init(struct net *net)
1534 struct netlink_kernel_cfg cfg = {
1535 .input = audit_receive,
1537 .flags = NL_CFG_F_NONROOT_RECV,
1538 .groups = AUDIT_NLGRP_MAX,
1541 struct audit_net *aunet = net_generic(net, audit_net_id);
1543 aunet->sk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
1544 if (aunet->sk == NULL) {
1545 audit_panic("cannot initialize netlink socket in namespace");
1548 aunet->sk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
1553 static void __net_exit audit_net_exit(struct net *net)
1555 struct audit_net *aunet = net_generic(net, audit_net_id);
1557 /* NOTE: you would think that we would want to check the auditd
1558 * connection and potentially reset it here if it lives in this
1559 * namespace, but since the auditd connection tracking struct holds a
1560 * reference to this namespace (see auditd_set()) we are only ever
1561 * going to get here after that connection has been released */
1563 netlink_kernel_release(aunet->sk);
1566 static struct pernet_operations audit_net_ops __net_initdata = {
1567 .init = audit_net_init,
1568 .exit = audit_net_exit,
1569 .id = &audit_net_id,
1570 .size = sizeof(struct audit_net),
1573 /* Initialize audit support at boot time. */
1574 static int __init audit_init(void)
1578 if (audit_initialized == AUDIT_DISABLED)
1581 audit_buffer_cache = kmem_cache_create("audit_buffer",
1582 sizeof(struct audit_buffer),
1583 0, SLAB_PANIC, NULL);
1585 skb_queue_head_init(&audit_queue);
1586 skb_queue_head_init(&audit_retry_queue);
1587 skb_queue_head_init(&audit_hold_queue);
1589 for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
1590 INIT_LIST_HEAD(&audit_inode_hash[i]);
1592 mutex_init(&audit_cmd_mutex.lock);
1593 audit_cmd_mutex.owner = NULL;
1595 pr_info("initializing netlink subsys (%s)\n",
1596 audit_default ? "enabled" : "disabled");
1597 register_pernet_subsys(&audit_net_ops);
1599 audit_initialized = AUDIT_INITIALIZED;
1601 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
1602 if (IS_ERR(kauditd_task)) {
1603 int err = PTR_ERR(kauditd_task);
1604 panic("audit: failed to start the kauditd thread (%d)\n", err);
1607 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL,
1608 "state=initialized audit_enabled=%u res=1",
1613 postcore_initcall(audit_init);
1616 * Process kernel command-line parameter at boot time.
1617 * audit={0|off} or audit={1|on}.
1619 static int __init audit_enable(char *str)
1621 if (!strcasecmp(str, "off") || !strcmp(str, "0"))
1622 audit_default = AUDIT_OFF;
1623 else if (!strcasecmp(str, "on") || !strcmp(str, "1"))
1624 audit_default = AUDIT_ON;
1626 pr_err("audit: invalid 'audit' parameter value (%s)\n", str);
1627 audit_default = AUDIT_ON;
1630 if (audit_default == AUDIT_OFF)
1631 audit_initialized = AUDIT_DISABLED;
1632 if (audit_set_enabled(audit_default))
1633 pr_err("audit: error setting audit state (%d)\n",
1636 pr_info("%s\n", audit_default ?
1637 "enabled (after initialization)" : "disabled (until reboot)");
1641 __setup("audit=", audit_enable);
1643 /* Process kernel command-line parameter at boot time.
1644 * audit_backlog_limit=<n> */
1645 static int __init audit_backlog_limit_set(char *str)
1647 u32 audit_backlog_limit_arg;
1649 pr_info("audit_backlog_limit: ");
1650 if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
1651 pr_cont("using default of %u, unable to parse %s\n",
1652 audit_backlog_limit, str);
1656 audit_backlog_limit = audit_backlog_limit_arg;
1657 pr_cont("%d\n", audit_backlog_limit);
1661 __setup("audit_backlog_limit=", audit_backlog_limit_set);
1663 static void audit_buffer_free(struct audit_buffer *ab)
1669 kmem_cache_free(audit_buffer_cache, ab);
1672 static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx,
1673 gfp_t gfp_mask, int type)
1675 struct audit_buffer *ab;
1677 ab = kmem_cache_alloc(audit_buffer_cache, gfp_mask);
1681 ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
1684 if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0))
1688 ab->gfp_mask = gfp_mask;
1693 audit_buffer_free(ab);
1698 * audit_serial - compute a serial number for the audit record
1700 * Compute a serial number for the audit record. Audit records are
1701 * written to user-space as soon as they are generated, so a complete
1702 * audit record may be written in several pieces. The timestamp of the
1703 * record and this serial number are used by the user-space tools to
1704 * determine which pieces belong to the same audit record. The
1705 * (timestamp,serial) tuple is unique for each syscall and is live from
1706 * syscall entry to syscall exit.
1708 * NOTE: Another possibility is to store the formatted records off the
1709 * audit context (for those records that have a context), and emit them
1710 * all at syscall exit. However, this could delay the reporting of
1711 * significant errors until syscall exit (or never, if the system
1714 unsigned int audit_serial(void)
1716 static atomic_t serial = ATOMIC_INIT(0);
1718 return atomic_add_return(1, &serial);
1721 static inline void audit_get_stamp(struct audit_context *ctx,
1722 struct timespec64 *t, unsigned int *serial)
1724 if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
1725 ktime_get_coarse_real_ts64(t);
1726 *serial = audit_serial();
1731 * audit_log_start - obtain an audit buffer
1732 * @ctx: audit_context (may be NULL)
1733 * @gfp_mask: type of allocation
1734 * @type: audit message type
1736 * Returns audit_buffer pointer on success or NULL on error.
1738 * Obtain an audit buffer. This routine does locking to obtain the
1739 * audit buffer, but then no locking is required for calls to
1740 * audit_log_*format. If the task (ctx) is a task that is currently in a
1741 * syscall, then the syscall is marked as auditable and an audit record
1742 * will be written at syscall exit. If there is no associated task, then
1743 * task context (ctx) should be NULL.
1745 struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1748 struct audit_buffer *ab;
1749 struct timespec64 t;
1750 unsigned int uninitialized_var(serial);
1752 if (audit_initialized != AUDIT_INITIALIZED)
1755 if (unlikely(!audit_filter(type, AUDIT_FILTER_EXCLUDE)))
1758 /* NOTE: don't ever fail/sleep on these two conditions:
1759 * 1. auditd generated record - since we need auditd to drain the
1760 * queue; also, when we are checking for auditd, compare PIDs using
1761 * task_tgid_vnr() since auditd_pid is set in audit_receive_msg()
1762 * using a PID anchored in the caller's namespace
1763 * 2. generator holding the audit_cmd_mutex - we don't want to block
1764 * while holding the mutex */
1765 if (!(auditd_test_task(current) || audit_ctl_owner_current())) {
1766 long stime = audit_backlog_wait_time;
1768 while (audit_backlog_limit &&
1769 (skb_queue_len(&audit_queue) > audit_backlog_limit)) {
1770 /* wake kauditd to try and flush the queue */
1771 wake_up_interruptible(&kauditd_wait);
1773 /* sleep if we are allowed and we haven't exhausted our
1774 * backlog wait limit */
1775 if (gfpflags_allow_blocking(gfp_mask) && (stime > 0)) {
1776 DECLARE_WAITQUEUE(wait, current);
1778 add_wait_queue_exclusive(&audit_backlog_wait,
1780 set_current_state(TASK_UNINTERRUPTIBLE);
1781 stime = schedule_timeout(stime);
1782 remove_wait_queue(&audit_backlog_wait, &wait);
1784 if (audit_rate_check() && printk_ratelimit())
1785 pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
1786 skb_queue_len(&audit_queue),
1787 audit_backlog_limit);
1788 audit_log_lost("backlog limit exceeded");
1794 ab = audit_buffer_alloc(ctx, gfp_mask, type);
1796 audit_log_lost("out of memory in audit_log_start");
1800 audit_get_stamp(ab->ctx, &t, &serial);
1801 audit_log_format(ab, "audit(%llu.%03lu:%u): ",
1802 (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
1808 * audit_expand - expand skb in the audit buffer
1810 * @extra: space to add at tail of the skb
1812 * Returns 0 (no space) on failed expansion, or available space if
1815 static inline int audit_expand(struct audit_buffer *ab, int extra)
1817 struct sk_buff *skb = ab->skb;
1818 int oldtail = skb_tailroom(skb);
1819 int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1820 int newtail = skb_tailroom(skb);
1823 audit_log_lost("out of memory in audit_expand");
1827 skb->truesize += newtail - oldtail;
1832 * Format an audit message into the audit buffer. If there isn't enough
1833 * room in the audit buffer, more room will be allocated and vsnprint
1834 * will be called a second time. Currently, we assume that a printk
1835 * can't format message larger than 1024 bytes, so we don't either.
1837 static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1841 struct sk_buff *skb;
1849 avail = skb_tailroom(skb);
1851 avail = audit_expand(ab, AUDIT_BUFSIZ);
1855 va_copy(args2, args);
1856 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1858 /* The printk buffer is 1024 bytes long, so if we get
1859 * here and AUDIT_BUFSIZ is at least 1024, then we can
1860 * log everything that printk could have logged. */
1861 avail = audit_expand(ab,
1862 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1865 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1876 * audit_log_format - format a message into the audit buffer.
1878 * @fmt: format string
1879 * @...: optional parameters matching @fmt string
1881 * All the work is done in audit_log_vformat.
1883 void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1889 va_start(args, fmt);
1890 audit_log_vformat(ab, fmt, args);
1895 * audit_log_n_hex - convert a buffer to hex and append it to the audit skb
1896 * @ab: the audit_buffer
1897 * @buf: buffer to convert to hex
1898 * @len: length of @buf to be converted
1900 * No return value; failure to expand is silently ignored.
1902 * This function will take the passed buf and convert it into a string of
1903 * ascii hex digits. The new string is placed onto the skb.
1905 void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
1908 int i, avail, new_len;
1910 struct sk_buff *skb;
1917 avail = skb_tailroom(skb);
1919 if (new_len >= avail) {
1920 /* Round the buffer request up to the next multiple */
1921 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1922 avail = audit_expand(ab, new_len);
1927 ptr = skb_tail_pointer(skb);
1928 for (i = 0; i < len; i++)
1929 ptr = hex_byte_pack_upper(ptr, buf[i]);
1931 skb_put(skb, len << 1); /* new string is twice the old string */
1935 * Format a string of no more than slen characters into the audit buffer,
1936 * enclosed in quote marks.
1938 void audit_log_n_string(struct audit_buffer *ab, const char *string,
1943 struct sk_buff *skb;
1950 avail = skb_tailroom(skb);
1951 new_len = slen + 3; /* enclosing quotes + null terminator */
1952 if (new_len > avail) {
1953 avail = audit_expand(ab, new_len);
1957 ptr = skb_tail_pointer(skb);
1959 memcpy(ptr, string, slen);
1963 skb_put(skb, slen + 2); /* don't include null terminator */
1967 * audit_string_contains_control - does a string need to be logged in hex
1968 * @string: string to be checked
1969 * @len: max length of the string to check
1971 bool audit_string_contains_control(const char *string, size_t len)
1973 const unsigned char *p;
1974 for (p = string; p < (const unsigned char *)string + len; p++) {
1975 if (*p == '"' || *p < 0x21 || *p > 0x7e)
1982 * audit_log_n_untrustedstring - log a string that may contain random characters
1984 * @len: length of string (not including trailing null)
1985 * @string: string to be logged
1987 * This code will escape a string that is passed to it if the string
1988 * contains a control character, unprintable character, double quote mark,
1989 * or a space. Unescaped strings will start and end with a double quote mark.
1990 * Strings that are escaped are printed in hex (2 digits per char).
1992 * The caller specifies the number of characters in the string to log, which may
1993 * or may not be the entire string.
1995 void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
1998 if (audit_string_contains_control(string, len))
1999 audit_log_n_hex(ab, string, len);
2001 audit_log_n_string(ab, string, len);
2005 * audit_log_untrustedstring - log a string that may contain random characters
2007 * @string: string to be logged
2009 * Same as audit_log_n_untrustedstring(), except that strlen is used to
2010 * determine string length.
2012 void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
2014 audit_log_n_untrustedstring(ab, string, strlen(string));
2017 /* This is a helper-function to print the escaped d_path */
2018 void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
2019 const struct path *path)
2024 audit_log_format(ab, "%s", prefix);
2026 /* We will allow 11 spaces for ' (deleted)' to be appended */
2027 pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
2029 audit_log_string(ab, "<no_memory>");
2032 p = d_path(path, pathname, PATH_MAX+11);
2033 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
2034 /* FIXME: can we save some information here? */
2035 audit_log_string(ab, "<too_long>");
2037 audit_log_untrustedstring(ab, p);
2041 void audit_log_session_info(struct audit_buffer *ab)
2043 unsigned int sessionid = audit_get_sessionid(current);
2044 uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
2046 audit_log_format(ab, "auid=%u ses=%u", auid, sessionid);
2049 void audit_log_key(struct audit_buffer *ab, char *key)
2051 audit_log_format(ab, " key=");
2053 audit_log_untrustedstring(ab, key);
2055 audit_log_format(ab, "(null)");
2058 void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap)
2062 if (cap_isclear(*cap)) {
2063 audit_log_format(ab, " %s=0", prefix);
2066 audit_log_format(ab, " %s=", prefix);
2068 audit_log_format(ab, "%08x", cap->cap[CAP_LAST_U32 - i]);
2071 static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
2073 audit_log_cap(ab, "cap_fp", &name->fcap.permitted);
2074 audit_log_cap(ab, "cap_fi", &name->fcap.inheritable);
2075 audit_log_format(ab, " cap_fe=%d cap_fver=%x",
2076 name->fcap.fE, name->fcap_ver);
2079 static inline int audit_copy_fcaps(struct audit_names *name,
2080 const struct dentry *dentry)
2082 struct cpu_vfs_cap_data caps;
2088 rc = get_vfs_caps_from_disk(dentry, &caps);
2092 name->fcap.permitted = caps.permitted;
2093 name->fcap.inheritable = caps.inheritable;
2094 name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
2095 name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >>
2096 VFS_CAP_REVISION_SHIFT;
2101 /* Copy inode data into an audit_names. */
2102 void audit_copy_inode(struct audit_names *name, const struct dentry *dentry,
2103 struct inode *inode)
2105 name->ino = inode->i_ino;
2106 name->dev = inode->i_sb->s_dev;
2107 name->mode = inode->i_mode;
2108 name->uid = inode->i_uid;
2109 name->gid = inode->i_gid;
2110 name->rdev = inode->i_rdev;
2111 security_inode_getsecid(inode, &name->osid);
2112 audit_copy_fcaps(name, dentry);
2116 * audit_log_name - produce AUDIT_PATH record from struct audit_names
2117 * @context: audit_context for the task
2118 * @n: audit_names structure with reportable details
2119 * @path: optional path to report instead of audit_names->name
2120 * @record_num: record number to report when handling a list of names
2121 * @call_panic: optional pointer to int that will be updated if secid fails
2123 void audit_log_name(struct audit_context *context, struct audit_names *n,
2124 const struct path *path, int record_num, int *call_panic)
2126 struct audit_buffer *ab;
2127 ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH);
2131 audit_log_format(ab, "item=%d", record_num);
2134 audit_log_d_path(ab, " name=", path);
2136 switch (n->name_len) {
2137 case AUDIT_NAME_FULL:
2138 /* log the full path */
2139 audit_log_format(ab, " name=");
2140 audit_log_untrustedstring(ab, n->name->name);
2143 /* name was specified as a relative path and the
2144 * directory component is the cwd */
2145 audit_log_d_path(ab, " name=", &context->pwd);
2148 /* log the name's directory component */
2149 audit_log_format(ab, " name=");
2150 audit_log_n_untrustedstring(ab, n->name->name,
2154 audit_log_format(ab, " name=(null)");
2156 if (n->ino != AUDIT_INO_UNSET)
2157 audit_log_format(ab, " inode=%lu"
2158 " dev=%02x:%02x mode=%#ho"
2159 " ouid=%u ogid=%u rdev=%02x:%02x",
2164 from_kuid(&init_user_ns, n->uid),
2165 from_kgid(&init_user_ns, n->gid),
2171 if (security_secid_to_secctx(
2172 n->osid, &ctx, &len)) {
2173 audit_log_format(ab, " osid=%u", n->osid);
2177 audit_log_format(ab, " obj=%s", ctx);
2178 security_release_secctx(ctx, len);
2182 /* log the audit_names record type */
2184 case AUDIT_TYPE_NORMAL:
2185 audit_log_format(ab, " nametype=NORMAL");
2187 case AUDIT_TYPE_PARENT:
2188 audit_log_format(ab, " nametype=PARENT");
2190 case AUDIT_TYPE_CHILD_DELETE:
2191 audit_log_format(ab, " nametype=DELETE");
2193 case AUDIT_TYPE_CHILD_CREATE:
2194 audit_log_format(ab, " nametype=CREATE");
2197 audit_log_format(ab, " nametype=UNKNOWN");
2201 audit_log_fcaps(ab, n);
2205 int audit_log_task_context(struct audit_buffer *ab)
2212 security_task_getsecid(current, &sid);
2216 error = security_secid_to_secctx(sid, &ctx, &len);
2218 if (error != -EINVAL)
2223 audit_log_format(ab, " subj=%s", ctx);
2224 security_release_secctx(ctx, len);
2228 audit_panic("error in audit_log_task_context");
2231 EXPORT_SYMBOL(audit_log_task_context);
2233 void audit_log_d_path_exe(struct audit_buffer *ab,
2234 struct mm_struct *mm)
2236 struct file *exe_file;
2241 exe_file = get_mm_exe_file(mm);
2245 audit_log_d_path(ab, " exe=", &exe_file->f_path);
2249 audit_log_format(ab, " exe=(null)");
2252 struct tty_struct *audit_get_tty(void)
2254 struct tty_struct *tty = NULL;
2255 unsigned long flags;
2257 spin_lock_irqsave(¤t->sighand->siglock, flags);
2258 if (current->signal)
2259 tty = tty_kref_get(current->signal->tty);
2260 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
2264 void audit_put_tty(struct tty_struct *tty)
2269 void audit_log_task_info(struct audit_buffer *ab)
2271 const struct cred *cred;
2272 char comm[sizeof(current->comm)];
2273 struct tty_struct *tty;
2278 cred = current_cred();
2279 tty = audit_get_tty();
2280 audit_log_format(ab,
2281 " ppid=%d pid=%d auid=%u uid=%u gid=%u"
2282 " euid=%u suid=%u fsuid=%u"
2283 " egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
2284 task_ppid_nr(current),
2285 task_tgid_nr(current),
2286 from_kuid(&init_user_ns, audit_get_loginuid(current)),
2287 from_kuid(&init_user_ns, cred->uid),
2288 from_kgid(&init_user_ns, cred->gid),
2289 from_kuid(&init_user_ns, cred->euid),
2290 from_kuid(&init_user_ns, cred->suid),
2291 from_kuid(&init_user_ns, cred->fsuid),
2292 from_kgid(&init_user_ns, cred->egid),
2293 from_kgid(&init_user_ns, cred->sgid),
2294 from_kgid(&init_user_ns, cred->fsgid),
2295 tty ? tty_name(tty) : "(none)",
2296 audit_get_sessionid(current));
2298 audit_log_format(ab, " comm=");
2299 audit_log_untrustedstring(ab, get_task_comm(comm, current));
2300 audit_log_d_path_exe(ab, current->mm);
2301 audit_log_task_context(ab);
2303 EXPORT_SYMBOL(audit_log_task_info);
2306 * audit_log_link_denied - report a link restriction denial
2307 * @operation: specific link operation
2309 void audit_log_link_denied(const char *operation)
2311 struct audit_buffer *ab;
2313 if (!audit_enabled || audit_dummy_context())
2316 /* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */
2317 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_ANOM_LINK);
2320 audit_log_format(ab, "op=%s", operation);
2321 audit_log_task_info(ab);
2322 audit_log_format(ab, " res=0");
2327 * audit_log_end - end one audit record
2328 * @ab: the audit_buffer
2330 * We can not do a netlink send inside an irq context because it blocks (last
2331 * arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a
2332 * queue and a tasklet is scheduled to remove them from the queue outside the
2333 * irq context. May be called in any context.
2335 void audit_log_end(struct audit_buffer *ab)
2337 struct sk_buff *skb;
2338 struct nlmsghdr *nlh;
2343 if (audit_rate_check()) {
2347 /* setup the netlink header, see the comments in
2348 * kauditd_send_multicast_skb() for length quirks */
2349 nlh = nlmsg_hdr(skb);
2350 nlh->nlmsg_len = skb->len - NLMSG_HDRLEN;
2352 /* queue the netlink packet and poke the kauditd thread */
2353 skb_queue_tail(&audit_queue, skb);
2354 wake_up_interruptible(&kauditd_wait);
2356 audit_log_lost("rate limit exceeded");
2358 audit_buffer_free(ab);
2362 * audit_log - Log an audit record
2363 * @ctx: audit context
2364 * @gfp_mask: type of allocation
2365 * @type: audit message type
2366 * @fmt: format string to use
2367 * @...: variable parameters matching the format string
2369 * This is a convenience function that calls audit_log_start,
2370 * audit_log_vformat, and audit_log_end. It may be called
2373 void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
2374 const char *fmt, ...)
2376 struct audit_buffer *ab;
2379 ab = audit_log_start(ctx, gfp_mask, type);
2381 va_start(args, fmt);
2382 audit_log_vformat(ab, fmt, args);
2388 EXPORT_SYMBOL(audit_log_start);
2389 EXPORT_SYMBOL(audit_log_end);
2390 EXPORT_SYMBOL(audit_log_format);
2391 EXPORT_SYMBOL(audit_log);