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 * Example user-space utilities: http://people.redhat.com/sgrubb/audit/
44 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
46 #include <linux/file.h>
47 #include <linux/init.h>
48 #include <linux/types.h>
49 #include <linux/atomic.h>
51 #include <linux/export.h>
52 #include <linux/slab.h>
53 #include <linux/err.h>
54 #include <linux/kthread.h>
55 #include <linux/kernel.h>
56 #include <linux/syscalls.h>
57 #include <linux/spinlock.h>
58 #include <linux/rcupdate.h>
59 #include <linux/mutex.h>
60 #include <linux/gfp.h>
62 #include <linux/audit.h>
65 #include <net/netlink.h>
66 #include <linux/skbuff.h>
67 #ifdef CONFIG_SECURITY
68 #include <linux/security.h>
70 #include <linux/freezer.h>
71 #include <linux/pid_namespace.h>
72 #include <net/netns/generic.h>
76 /* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
77 * (Initialization happens after skb_init is called.) */
78 #define AUDIT_DISABLED -1
79 #define AUDIT_UNINITIALIZED 0
80 #define AUDIT_INITIALIZED 1
81 static int audit_initialized;
85 #define AUDIT_LOCKED 2
87 u32 audit_ever_enabled;
89 EXPORT_SYMBOL_GPL(audit_enabled);
91 /* Default state when kernel boots without any parameters. */
92 static u32 audit_default;
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
113 * @lock: spinlock to protect write access
116 * This struct is RCU protected; you must either hold the RCU lock for reading
117 * or the included spinlock for writing.
119 static struct auditd_connection {
126 /* If audit_rate_limit is non-zero, limit the rate of sending audit records
127 * to that number per second. This prevents DoS attacks, but results in
128 * audit records being dropped. */
129 static u32 audit_rate_limit;
131 /* Number of outstanding audit_buffers allowed.
132 * When set to zero, this means unlimited. */
133 static u32 audit_backlog_limit = 64;
134 #define AUDIT_BACKLOG_WAIT_TIME (60 * HZ)
135 static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
137 /* The identity of the user shutting down the audit system. */
138 kuid_t audit_sig_uid = INVALID_UID;
139 pid_t audit_sig_pid = -1;
140 u32 audit_sig_sid = 0;
142 /* Records can be lost in several ways:
143 0) [suppressed in audit_alloc]
144 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
145 2) out of memory in audit_log_move [alloc_skb]
146 3) suppressed due to audit_rate_limit
147 4) suppressed due to audit_backlog_limit
149 static atomic_t audit_lost = ATOMIC_INIT(0);
151 /* Hash for inode-based rules */
152 struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
154 /* The audit_freelist is a list of pre-allocated audit buffers (if more
155 * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
156 * being placed on the freelist). */
157 static DEFINE_SPINLOCK(audit_freelist_lock);
158 static int audit_freelist_count;
159 static LIST_HEAD(audit_freelist);
161 /* queue msgs to send via kauditd_task */
162 static struct sk_buff_head audit_queue;
163 /* queue msgs due to temporary unicast send problems */
164 static struct sk_buff_head audit_retry_queue;
165 /* queue msgs waiting for new auditd connection */
166 static struct sk_buff_head audit_hold_queue;
168 /* queue servicing thread */
169 static struct task_struct *kauditd_task;
170 static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
172 /* waitqueue for callers who are blocked on the audit backlog */
173 static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
175 static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION,
180 static char *audit_feature_names[2] = {
181 "only_unset_loginuid",
182 "loginuid_immutable",
186 /* Serialize requests from userspace. */
187 DEFINE_MUTEX(audit_cmd_mutex);
189 /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
190 * audit records. Since printk uses a 1024 byte buffer, this buffer
191 * should be at least that large. */
192 #define AUDIT_BUFSIZ 1024
194 /* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the
195 * audit_freelist. Doing so eliminates many kmalloc/kfree calls. */
196 #define AUDIT_MAXFREE (2*NR_CPUS)
198 /* The audit_buffer is used when formatting an audit record. The caller
199 * locks briefly to get the record off the freelist or to allocate the
200 * buffer, and locks briefly to send the buffer to the netlink layer or
201 * to place it on a transmit queue. Multiple audit_buffers can be in
202 * use simultaneously. */
203 struct audit_buffer {
204 struct list_head list;
205 struct sk_buff *skb; /* formatted skb ready to send */
206 struct audit_context *ctx; /* NULL or associated context */
217 * auditd_test_task - Check to see if a given task is an audit daemon
218 * @task: the task to check
221 * Return 1 if the task is a registered audit daemon, 0 otherwise.
223 int auditd_test_task(const struct task_struct *task)
228 rc = (auditd_conn.pid && task->tgid == auditd_conn.pid ? 1 : 0);
235 * audit_get_sk - Return the audit socket for the given network namespace
236 * @net: the destination network namespace
239 * Returns the sock pointer if valid, NULL otherwise. The caller must ensure
240 * that a reference is held for the network namespace while the sock is in use.
242 static struct sock *audit_get_sk(const struct net *net)
244 struct audit_net *aunet;
249 aunet = net_generic(net, audit_net_id);
253 void audit_panic(const char *message)
255 switch (audit_failure) {
256 case AUDIT_FAIL_SILENT:
258 case AUDIT_FAIL_PRINTK:
259 if (printk_ratelimit())
260 pr_err("%s\n", message);
262 case AUDIT_FAIL_PANIC:
263 panic("audit: %s\n", message);
268 static inline int audit_rate_check(void)
270 static unsigned long last_check = 0;
271 static int messages = 0;
272 static DEFINE_SPINLOCK(lock);
275 unsigned long elapsed;
278 if (!audit_rate_limit) return 1;
280 spin_lock_irqsave(&lock, flags);
281 if (++messages < audit_rate_limit) {
285 elapsed = now - last_check;
292 spin_unlock_irqrestore(&lock, flags);
298 * audit_log_lost - conditionally log lost audit message event
299 * @message: the message stating reason for lost audit message
301 * Emit at least 1 message per second, even if audit_rate_check is
303 * Always increment the lost messages counter.
305 void audit_log_lost(const char *message)
307 static unsigned long last_msg = 0;
308 static DEFINE_SPINLOCK(lock);
313 atomic_inc(&audit_lost);
315 print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
318 spin_lock_irqsave(&lock, flags);
320 if (now - last_msg > HZ) {
324 spin_unlock_irqrestore(&lock, flags);
328 if (printk_ratelimit())
329 pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
330 atomic_read(&audit_lost),
332 audit_backlog_limit);
333 audit_panic(message);
337 static int audit_log_config_change(char *function_name, u32 new, u32 old,
340 struct audit_buffer *ab;
343 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
346 audit_log_format(ab, "%s=%u old=%u", function_name, new, old);
347 audit_log_session_info(ab);
348 rc = audit_log_task_context(ab);
350 allow_changes = 0; /* Something weird, deny request */
351 audit_log_format(ab, " res=%d", allow_changes);
356 static int audit_do_config_change(char *function_name, u32 *to_change, u32 new)
358 int allow_changes, rc = 0;
359 u32 old = *to_change;
361 /* check if we are locked */
362 if (audit_enabled == AUDIT_LOCKED)
367 if (audit_enabled != AUDIT_OFF) {
368 rc = audit_log_config_change(function_name, new, old, allow_changes);
373 /* If we are allowed, make the change */
374 if (allow_changes == 1)
376 /* Not allowed, update reason */
382 static int audit_set_rate_limit(u32 limit)
384 return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit);
387 static int audit_set_backlog_limit(u32 limit)
389 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit);
392 static int audit_set_backlog_wait_time(u32 timeout)
394 return audit_do_config_change("audit_backlog_wait_time",
395 &audit_backlog_wait_time, timeout);
398 static int audit_set_enabled(u32 state)
401 if (state > AUDIT_LOCKED)
404 rc = audit_do_config_change("audit_enabled", &audit_enabled, state);
406 audit_ever_enabled |= !!state;
411 static int audit_set_failure(u32 state)
413 if (state != AUDIT_FAIL_SILENT
414 && state != AUDIT_FAIL_PRINTK
415 && state != AUDIT_FAIL_PANIC)
418 return audit_do_config_change("audit_failure", &audit_failure, state);
422 * auditd_set - Set/Reset the auditd connection state
424 * @portid: auditd netlink portid
425 * @net: auditd network namespace pointer
428 * This function will obtain and drop network namespace references as
431 static void auditd_set(int pid, u32 portid, struct net *net)
435 spin_lock_irqsave(&auditd_conn.lock, flags);
436 auditd_conn.pid = pid;
437 auditd_conn.portid = portid;
439 put_net(auditd_conn.net);
441 auditd_conn.net = get_net(net);
443 auditd_conn.net = NULL;
444 spin_unlock_irqrestore(&auditd_conn.lock, flags);
448 * kauditd_print_skb - Print the audit record to the ring buffer
451 * Whatever the reason, this packet may not make it to the auditd connection
452 * so write it via printk so the information isn't completely lost.
454 static void kauditd_printk_skb(struct sk_buff *skb)
456 struct nlmsghdr *nlh = nlmsg_hdr(skb);
457 char *data = nlmsg_data(nlh);
459 if (nlh->nlmsg_type != AUDIT_EOE && printk_ratelimit())
460 pr_notice("type=%d %s\n", nlh->nlmsg_type, data);
464 * kauditd_rehold_skb - Handle a audit record send failure in the hold queue
468 * This should only be used by the kauditd_thread when it fails to flush the
471 static void kauditd_rehold_skb(struct sk_buff *skb)
473 /* put the record back in the queue at the same place */
474 skb_queue_head(&audit_hold_queue, skb);
478 * kauditd_hold_skb - Queue an audit record, waiting for auditd
482 * Queue the audit record, waiting for an instance of auditd. When this
483 * function is called we haven't given up yet on sending the record, but things
484 * are not looking good. The first thing we want to do is try to write the
485 * record via printk and then see if we want to try and hold on to the record
486 * and queue it, if we have room. If we want to hold on to the record, but we
487 * don't have room, record a record lost message.
489 static void kauditd_hold_skb(struct sk_buff *skb)
491 /* at this point it is uncertain if we will ever send this to auditd so
492 * try to send the message via printk before we go any further */
493 kauditd_printk_skb(skb);
495 /* can we just silently drop the message? */
496 if (!audit_default) {
501 /* if we have room, queue the message */
502 if (!audit_backlog_limit ||
503 skb_queue_len(&audit_hold_queue) < audit_backlog_limit) {
504 skb_queue_tail(&audit_hold_queue, skb);
508 /* we have no other options - drop the message */
509 audit_log_lost("kauditd hold queue overflow");
514 * kauditd_retry_skb - Queue an audit record, attempt to send again to auditd
518 * Not as serious as kauditd_hold_skb() as we still have a connected auditd,
519 * but for some reason we are having problems sending it audit records so
520 * queue the given record and attempt to resend.
522 static void kauditd_retry_skb(struct sk_buff *skb)
524 /* NOTE: because records should only live in the retry queue for a
525 * short period of time, before either being sent or moved to the hold
526 * queue, we don't currently enforce a limit on this queue */
527 skb_queue_tail(&audit_retry_queue, skb);
531 * auditd_reset - Disconnect the auditd connection
534 * Break the auditd/kauditd connection and move all the queued records into the
535 * hold queue in case auditd reconnects.
537 static void auditd_reset(void)
541 /* if it isn't already broken, break the connection */
544 auditd_set(0, 0, NULL);
547 /* flush all of the main and retry queues to the hold queue */
548 while ((skb = skb_dequeue(&audit_retry_queue)))
549 kauditd_hold_skb(skb);
550 while ((skb = skb_dequeue(&audit_queue)))
551 kauditd_hold_skb(skb);
555 * auditd_send_unicast_skb - Send a record via unicast to auditd
559 * Send a skb to the audit daemon, returns positive/zero values on success and
560 * negative values on failure; in all cases the skb will be consumed by this
561 * function. If the send results in -ECONNREFUSED the connection with auditd
562 * will be reset. This function may sleep so callers should not hold any locks
563 * where this would cause a problem.
565 static int auditd_send_unicast_skb(struct sk_buff *skb)
572 /* NOTE: we can't call netlink_unicast while in the RCU section so
573 * take a reference to the network namespace and grab local
574 * copies of the namespace, the sock, and the portid; the
575 * namespace and sock aren't going to go away while we hold a
576 * reference and if the portid does become invalid after the RCU
577 * section netlink_unicast() should safely return an error */
580 if (!auditd_conn.pid) {
585 net = auditd_conn.net;
587 sk = audit_get_sk(net);
588 portid = auditd_conn.portid;
591 rc = netlink_unicast(sk, skb, portid, 0);
599 if (rc == -ECONNREFUSED)
605 * kauditd_send_queue - Helper for kauditd_thread to flush skb queues
606 * @sk: the sending sock
607 * @portid: the netlink destination
608 * @queue: the skb queue to process
609 * @retry_limit: limit on number of netlink unicast failures
610 * @skb_hook: per-skb hook for additional processing
611 * @err_hook: hook called if the skb fails the netlink unicast send
614 * Run through the given queue and attempt to send the audit records to auditd,
615 * returns zero on success, negative values on failure. It is up to the caller
616 * to ensure that the @sk is valid for the duration of this function.
619 static int kauditd_send_queue(struct sock *sk, u32 portid,
620 struct sk_buff_head *queue,
621 unsigned int retry_limit,
622 void (*skb_hook)(struct sk_buff *skb),
623 void (*err_hook)(struct sk_buff *skb))
627 static unsigned int failed = 0;
629 /* NOTE: kauditd_thread takes care of all our locking, we just use
630 * the netlink info passed to us (e.g. sk and portid) */
632 while ((skb = skb_dequeue(queue))) {
633 /* call the skb_hook for each skb we touch */
637 /* can we send to anyone via unicast? */
644 /* grab an extra skb reference in case of error */
646 rc = netlink_unicast(sk, skb, portid, 0);
648 /* fatal failure for our queue flush attempt? */
649 if (++failed >= retry_limit ||
650 rc == -ECONNREFUSED || rc == -EPERM) {
651 /* yes - error processing for the queue */
657 /* keep processing with the skb_hook */
660 /* no - requeue to preserve ordering */
661 skb_queue_head(queue, skb);
663 /* it worked - drop the extra reference and continue */
670 return (rc >= 0 ? 0 : rc);
674 * kauditd_send_multicast_skb - Send a record to any multicast listeners
678 * Write a multicast message to anyone listening in the initial network
679 * namespace. This function doesn't consume an skb as might be expected since
680 * it has to copy it anyways.
682 static void kauditd_send_multicast_skb(struct sk_buff *skb)
684 struct sk_buff *copy;
685 struct sock *sock = audit_get_sk(&init_net);
686 struct nlmsghdr *nlh;
688 /* NOTE: we are not taking an additional reference for init_net since
689 * we don't have to worry about it going away */
691 if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
695 * The seemingly wasteful skb_copy() rather than bumping the refcount
696 * using skb_get() is necessary because non-standard mods are made to
697 * the skb by the original kaudit unicast socket send routine. The
698 * existing auditd daemon assumes this breakage. Fixing this would
699 * require co-ordinating a change in the established protocol between
700 * the kaudit kernel subsystem and the auditd userspace code. There is
701 * no reason for new multicast clients to continue with this
704 copy = skb_copy(skb, GFP_KERNEL);
707 nlh = nlmsg_hdr(copy);
708 nlh->nlmsg_len = skb->len;
710 nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL);
714 * kauditd_thread - Worker thread to send audit records to userspace
717 static int kauditd_thread(void *dummy)
721 struct net *net = NULL;
722 struct sock *sk = NULL;
724 #define UNICAST_RETRIES 5
727 while (!kthread_should_stop()) {
728 /* NOTE: see the lock comments in auditd_send_unicast_skb() */
730 if (!auditd_conn.pid) {
734 net = auditd_conn.net;
736 sk = audit_get_sk(net);
737 portid = auditd_conn.portid;
740 /* attempt to flush the hold queue */
741 rc = kauditd_send_queue(sk, portid,
742 &audit_hold_queue, UNICAST_RETRIES,
743 NULL, kauditd_rehold_skb);
750 /* attempt to flush the retry queue */
751 rc = kauditd_send_queue(sk, portid,
752 &audit_retry_queue, UNICAST_RETRIES,
753 NULL, kauditd_hold_skb);
761 /* process the main queue - do the multicast send and attempt
762 * unicast, dump failed record sends to the retry queue; if
763 * sk == NULL due to previous failures we will just do the
764 * multicast send and move the record to the retry queue */
765 rc = kauditd_send_queue(sk, portid, &audit_queue, 1,
766 kauditd_send_multicast_skb,
768 if (sk == NULL || rc < 0)
772 /* drop our netns reference, no auditd sends past this line */
778 /* we have processed all the queues so wake everyone */
779 wake_up(&audit_backlog_wait);
781 /* NOTE: we want to wake up if there is anything on the queue,
782 * regardless of if an auditd is connected, as we need to
783 * do the multicast send and rotate records from the
784 * main queue to the retry/hold queues */
785 wait_event_freezable(kauditd_wait,
786 (skb_queue_len(&audit_queue) ? 1 : 0));
792 int audit_send_list(void *_dest)
794 struct audit_netlink_list *dest = _dest;
796 struct sock *sk = audit_get_sk(dest->net);
798 /* wait for parent to finish and send an ACK */
799 mutex_lock(&audit_cmd_mutex);
800 mutex_unlock(&audit_cmd_mutex);
802 while ((skb = __skb_dequeue(&dest->q)) != NULL)
803 netlink_unicast(sk, skb, dest->portid, 0);
811 struct sk_buff *audit_make_reply(int seq, int type, int done,
812 int multi, const void *payload, int size)
815 struct nlmsghdr *nlh;
817 int flags = multi ? NLM_F_MULTI : 0;
818 int t = done ? NLMSG_DONE : type;
820 skb = nlmsg_new(size, GFP_KERNEL);
824 nlh = nlmsg_put(skb, 0, seq, t, size, flags);
827 data = nlmsg_data(nlh);
828 memcpy(data, payload, size);
836 static int audit_send_reply_thread(void *arg)
838 struct audit_reply *reply = (struct audit_reply *)arg;
839 struct sock *sk = audit_get_sk(reply->net);
841 mutex_lock(&audit_cmd_mutex);
842 mutex_unlock(&audit_cmd_mutex);
844 /* Ignore failure. It'll only happen if the sender goes away,
845 because our timeout is set to infinite. */
846 netlink_unicast(sk, reply->skb, reply->portid, 0);
853 * audit_send_reply - send an audit reply message via netlink
854 * @request_skb: skb of request we are replying to (used to target the reply)
855 * @seq: sequence number
856 * @type: audit message type
857 * @done: done (last) flag
858 * @multi: multi-part message flag
859 * @payload: payload data
860 * @size: payload size
862 * Allocates an skb, builds the netlink message, and sends it to the port id.
863 * No failure notifications.
865 static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
866 int multi, const void *payload, int size)
868 struct net *net = sock_net(NETLINK_CB(request_skb).sk);
870 struct task_struct *tsk;
871 struct audit_reply *reply = kmalloc(sizeof(struct audit_reply),
877 skb = audit_make_reply(seq, type, done, multi, payload, size);
881 reply->net = get_net(net);
882 reply->portid = NETLINK_CB(request_skb).portid;
885 tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
894 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
897 static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
901 /* Only support initial user namespace for now. */
903 * We return ECONNREFUSED because it tricks userspace into thinking
904 * that audit was not configured into the kernel. Lots of users
905 * configure their PAM stack (because that's what the distro does)
906 * to reject login if unable to send messages to audit. If we return
907 * ECONNREFUSED the PAM stack thinks the kernel does not have audit
908 * configured in and will let login proceed. If we return EPERM
909 * userspace will reject all logins. This should be removed when we
910 * support non init namespaces!!
912 if (current_user_ns() != &init_user_ns)
913 return -ECONNREFUSED;
922 case AUDIT_GET_FEATURE:
923 case AUDIT_SET_FEATURE:
924 case AUDIT_LIST_RULES:
927 case AUDIT_SIGNAL_INFO:
931 case AUDIT_MAKE_EQUIV:
932 /* Only support auditd and auditctl in initial pid namespace
934 if (task_active_pid_ns(current) != &init_pid_ns)
937 if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
941 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
942 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
943 if (!netlink_capable(skb, CAP_AUDIT_WRITE))
946 default: /* bad msg */
953 static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
955 uid_t uid = from_kuid(&init_user_ns, current_uid());
956 pid_t pid = task_tgid_nr(current);
958 if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
963 *ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
966 audit_log_format(*ab, "pid=%d uid=%u", pid, uid);
967 audit_log_session_info(*ab);
968 audit_log_task_context(*ab);
971 int is_audit_feature_set(int i)
973 return af.features & AUDIT_FEATURE_TO_MASK(i);
977 static int audit_get_feature(struct sk_buff *skb)
981 seq = nlmsg_hdr(skb)->nlmsg_seq;
983 audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af));
988 static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
989 u32 old_lock, u32 new_lock, int res)
991 struct audit_buffer *ab;
993 if (audit_enabled == AUDIT_OFF)
996 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_FEATURE_CHANGE);
997 audit_log_task_info(ab, current);
998 audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
999 audit_feature_names[which], !!old_feature, !!new_feature,
1000 !!old_lock, !!new_lock, res);
1004 static int audit_set_feature(struct sk_buff *skb)
1006 struct audit_features *uaf;
1009 BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
1010 uaf = nlmsg_data(nlmsg_hdr(skb));
1012 /* if there is ever a version 2 we should handle that here */
1014 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1015 u32 feature = AUDIT_FEATURE_TO_MASK(i);
1016 u32 old_feature, new_feature, old_lock, new_lock;
1018 /* if we are not changing this feature, move along */
1019 if (!(feature & uaf->mask))
1022 old_feature = af.features & feature;
1023 new_feature = uaf->features & feature;
1024 new_lock = (uaf->lock | af.lock) & feature;
1025 old_lock = af.lock & feature;
1027 /* are we changing a locked feature? */
1028 if (old_lock && (new_feature != old_feature)) {
1029 audit_log_feature_change(i, old_feature, new_feature,
1030 old_lock, new_lock, 0);
1034 /* nothing invalid, do the changes */
1035 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1036 u32 feature = AUDIT_FEATURE_TO_MASK(i);
1037 u32 old_feature, new_feature, old_lock, new_lock;
1039 /* if we are not changing this feature, move along */
1040 if (!(feature & uaf->mask))
1043 old_feature = af.features & feature;
1044 new_feature = uaf->features & feature;
1045 old_lock = af.lock & feature;
1046 new_lock = (uaf->lock | af.lock) & feature;
1048 if (new_feature != old_feature)
1049 audit_log_feature_change(i, old_feature, new_feature,
1050 old_lock, new_lock, 1);
1053 af.features |= feature;
1055 af.features &= ~feature;
1056 af.lock |= new_lock;
1062 static int audit_replace(pid_t pid)
1064 struct sk_buff *skb;
1066 skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pid, sizeof(pid));
1069 return auditd_send_unicast_skb(skb);
1072 static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
1077 struct audit_buffer *ab;
1078 u16 msg_type = nlh->nlmsg_type;
1079 struct audit_sig_info *sig_data;
1083 err = audit_netlink_ok(skb, msg_type);
1087 seq = nlh->nlmsg_seq;
1088 data = nlmsg_data(nlh);
1092 struct audit_status s;
1093 memset(&s, 0, sizeof(s));
1094 s.enabled = audit_enabled;
1095 s.failure = audit_failure;
1097 s.pid = auditd_conn.pid;
1099 s.rate_limit = audit_rate_limit;
1100 s.backlog_limit = audit_backlog_limit;
1101 s.lost = atomic_read(&audit_lost);
1102 s.backlog = skb_queue_len(&audit_queue);
1103 s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL;
1104 s.backlog_wait_time = audit_backlog_wait_time;
1105 audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
1109 struct audit_status s;
1110 memset(&s, 0, sizeof(s));
1111 /* guard against past and future API changes */
1112 memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
1113 if (s.mask & AUDIT_STATUS_ENABLED) {
1114 err = audit_set_enabled(s.enabled);
1118 if (s.mask & AUDIT_STATUS_FAILURE) {
1119 err = audit_set_failure(s.failure);
1123 if (s.mask & AUDIT_STATUS_PID) {
1124 /* NOTE: we are using task_tgid_vnr() below because
1125 * the s.pid value is relative to the namespace
1126 * of the caller; at present this doesn't matter
1127 * much since you can really only run auditd
1128 * from the initial pid namespace, but something
1129 * to keep in mind if this changes */
1130 int new_pid = s.pid;
1132 pid_t requesting_pid = task_tgid_vnr(current);
1134 /* test the auditd connection */
1135 audit_replace(requesting_pid);
1138 auditd_pid = auditd_conn.pid;
1139 /* only the current auditd can unregister itself */
1140 if ((!new_pid) && (requesting_pid != auditd_pid)) {
1142 audit_log_config_change("audit_pid", new_pid,
1146 /* replacing a healthy auditd is not allowed */
1147 if (auditd_pid && new_pid) {
1149 audit_log_config_change("audit_pid", new_pid,
1155 if (audit_enabled != AUDIT_OFF)
1156 audit_log_config_change("audit_pid", new_pid,
1160 /* register a new auditd connection */
1162 NETLINK_CB(skb).portid,
1163 sock_net(NETLINK_CB(skb).sk));
1164 /* try to process any backlog */
1165 wake_up_interruptible(&kauditd_wait);
1167 /* unregister the auditd connection */
1170 if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
1171 err = audit_set_rate_limit(s.rate_limit);
1175 if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
1176 err = audit_set_backlog_limit(s.backlog_limit);
1180 if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
1181 if (sizeof(s) > (size_t)nlh->nlmsg_len)
1183 if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
1185 err = audit_set_backlog_wait_time(s.backlog_wait_time);
1189 if (s.mask == AUDIT_STATUS_LOST) {
1190 u32 lost = atomic_xchg(&audit_lost, 0);
1192 audit_log_config_change("lost", 0, lost, 1);
1197 case AUDIT_GET_FEATURE:
1198 err = audit_get_feature(skb);
1202 case AUDIT_SET_FEATURE:
1203 err = audit_set_feature(skb);
1208 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1209 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1210 if (!audit_enabled && msg_type != AUDIT_USER_AVC)
1213 err = audit_filter(msg_type, AUDIT_FILTER_USER);
1214 if (err == 1) { /* match or error */
1216 if (msg_type == AUDIT_USER_TTY) {
1217 err = tty_audit_push();
1221 audit_log_common_recv_msg(&ab, msg_type);
1222 if (msg_type != AUDIT_USER_TTY)
1223 audit_log_format(ab, " msg='%.*s'",
1224 AUDIT_MESSAGE_TEXT_MAX,
1229 audit_log_format(ab, " data=");
1230 size = nlmsg_len(nlh);
1232 ((unsigned char *)data)[size - 1] == '\0')
1234 audit_log_n_untrustedstring(ab, data, size);
1239 case AUDIT_ADD_RULE:
1240 case AUDIT_DEL_RULE:
1241 if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
1243 if (audit_enabled == AUDIT_LOCKED) {
1244 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1245 audit_log_format(ab, " audit_enabled=%d res=0", audit_enabled);
1249 err = audit_rule_change(msg_type, seq, data, nlmsg_len(nlh));
1251 case AUDIT_LIST_RULES:
1252 err = audit_list_rules_send(skb, seq);
1256 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1257 audit_log_format(ab, " op=trim res=1");
1260 case AUDIT_MAKE_EQUIV: {
1263 size_t msglen = nlmsg_len(nlh);
1267 if (msglen < 2 * sizeof(u32))
1269 memcpy(sizes, bufp, 2 * sizeof(u32));
1270 bufp += 2 * sizeof(u32);
1271 msglen -= 2 * sizeof(u32);
1272 old = audit_unpack_string(&bufp, &msglen, sizes[0]);
1277 new = audit_unpack_string(&bufp, &msglen, sizes[1]);
1283 /* OK, here comes... */
1284 err = audit_tag_tree(old, new);
1286 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1288 audit_log_format(ab, " op=make_equiv old=");
1289 audit_log_untrustedstring(ab, old);
1290 audit_log_format(ab, " new=");
1291 audit_log_untrustedstring(ab, new);
1292 audit_log_format(ab, " res=%d", !err);
1298 case AUDIT_SIGNAL_INFO:
1300 if (audit_sig_sid) {
1301 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
1305 sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
1308 security_release_secctx(ctx, len);
1311 sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
1312 sig_data->pid = audit_sig_pid;
1313 if (audit_sig_sid) {
1314 memcpy(sig_data->ctx, ctx, len);
1315 security_release_secctx(ctx, len);
1317 audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
1318 sig_data, sizeof(*sig_data) + len);
1321 case AUDIT_TTY_GET: {
1322 struct audit_tty_status s;
1325 t = READ_ONCE(current->signal->audit_tty);
1326 s.enabled = t & AUDIT_TTY_ENABLE;
1327 s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1329 audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
1332 case AUDIT_TTY_SET: {
1333 struct audit_tty_status s, old;
1334 struct audit_buffer *ab;
1337 memset(&s, 0, sizeof(s));
1338 /* guard against past and future API changes */
1339 memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
1340 /* check if new data is valid */
1341 if ((s.enabled != 0 && s.enabled != 1) ||
1342 (s.log_passwd != 0 && s.log_passwd != 1))
1346 t = READ_ONCE(current->signal->audit_tty);
1348 t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD);
1349 t = xchg(¤t->signal->audit_tty, t);
1351 old.enabled = t & AUDIT_TTY_ENABLE;
1352 old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1354 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1355 audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
1356 " old-log_passwd=%d new-log_passwd=%d res=%d",
1357 old.enabled, s.enabled, old.log_passwd,
1358 s.log_passwd, !err);
1367 return err < 0 ? err : 0;
1371 * audit_receive - receive messages from a netlink control socket
1372 * @skb: the message buffer
1374 * Parse the provided skb and deal with any messages that may be present,
1375 * malformed skbs are discarded.
1377 static void audit_receive(struct sk_buff *skb)
1379 struct nlmsghdr *nlh;
1381 * len MUST be signed for nlmsg_next to be able to dec it below 0
1382 * if the nlmsg_len was not aligned
1387 nlh = nlmsg_hdr(skb);
1390 mutex_lock(&audit_cmd_mutex);
1391 while (nlmsg_ok(nlh, len)) {
1392 err = audit_receive_msg(skb, nlh);
1393 /* if err or if this message says it wants a response */
1394 if (err || (nlh->nlmsg_flags & NLM_F_ACK))
1395 netlink_ack(skb, nlh, err);
1397 nlh = nlmsg_next(nlh, &len);
1399 mutex_unlock(&audit_cmd_mutex);
1402 /* Run custom bind function on netlink socket group connect or bind requests. */
1403 static int audit_bind(struct net *net, int group)
1405 if (!capable(CAP_AUDIT_READ))
1411 static int __net_init audit_net_init(struct net *net)
1413 struct netlink_kernel_cfg cfg = {
1414 .input = audit_receive,
1416 .flags = NL_CFG_F_NONROOT_RECV,
1417 .groups = AUDIT_NLGRP_MAX,
1420 struct audit_net *aunet = net_generic(net, audit_net_id);
1422 aunet->sk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
1423 if (aunet->sk == NULL) {
1424 audit_panic("cannot initialize netlink socket in namespace");
1427 aunet->sk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
1432 static void __net_exit audit_net_exit(struct net *net)
1434 struct audit_net *aunet = net_generic(net, audit_net_id);
1437 if (net == auditd_conn.net)
1441 netlink_kernel_release(aunet->sk);
1444 static struct pernet_operations audit_net_ops __net_initdata = {
1445 .init = audit_net_init,
1446 .exit = audit_net_exit,
1447 .id = &audit_net_id,
1448 .size = sizeof(struct audit_net),
1451 /* Initialize audit support at boot time. */
1452 static int __init audit_init(void)
1456 if (audit_initialized == AUDIT_DISABLED)
1459 memset(&auditd_conn, 0, sizeof(auditd_conn));
1460 spin_lock_init(&auditd_conn.lock);
1462 skb_queue_head_init(&audit_queue);
1463 skb_queue_head_init(&audit_retry_queue);
1464 skb_queue_head_init(&audit_hold_queue);
1466 for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
1467 INIT_LIST_HEAD(&audit_inode_hash[i]);
1469 pr_info("initializing netlink subsys (%s)\n",
1470 audit_default ? "enabled" : "disabled");
1471 register_pernet_subsys(&audit_net_ops);
1473 audit_initialized = AUDIT_INITIALIZED;
1474 audit_enabled = audit_default;
1475 audit_ever_enabled |= !!audit_default;
1477 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
1478 if (IS_ERR(kauditd_task)) {
1479 int err = PTR_ERR(kauditd_task);
1480 panic("audit: failed to start the kauditd thread (%d)\n", err);
1483 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL,
1484 "state=initialized audit_enabled=%u res=1",
1489 __initcall(audit_init);
1491 /* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
1492 static int __init audit_enable(char *str)
1494 audit_default = !!simple_strtol(str, NULL, 0);
1496 audit_initialized = AUDIT_DISABLED;
1498 pr_info("%s\n", audit_default ?
1499 "enabled (after initialization)" : "disabled (until reboot)");
1503 __setup("audit=", audit_enable);
1505 /* Process kernel command-line parameter at boot time.
1506 * audit_backlog_limit=<n> */
1507 static int __init audit_backlog_limit_set(char *str)
1509 u32 audit_backlog_limit_arg;
1511 pr_info("audit_backlog_limit: ");
1512 if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
1513 pr_cont("using default of %u, unable to parse %s\n",
1514 audit_backlog_limit, str);
1518 audit_backlog_limit = audit_backlog_limit_arg;
1519 pr_cont("%d\n", audit_backlog_limit);
1523 __setup("audit_backlog_limit=", audit_backlog_limit_set);
1525 static void audit_buffer_free(struct audit_buffer *ab)
1527 unsigned long flags;
1533 spin_lock_irqsave(&audit_freelist_lock, flags);
1534 if (audit_freelist_count > AUDIT_MAXFREE)
1537 audit_freelist_count++;
1538 list_add(&ab->list, &audit_freelist);
1540 spin_unlock_irqrestore(&audit_freelist_lock, flags);
1543 static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx,
1544 gfp_t gfp_mask, int type)
1546 unsigned long flags;
1547 struct audit_buffer *ab = NULL;
1548 struct nlmsghdr *nlh;
1550 spin_lock_irqsave(&audit_freelist_lock, flags);
1551 if (!list_empty(&audit_freelist)) {
1552 ab = list_entry(audit_freelist.next,
1553 struct audit_buffer, list);
1554 list_del(&ab->list);
1555 --audit_freelist_count;
1557 spin_unlock_irqrestore(&audit_freelist_lock, flags);
1560 ab = kmalloc(sizeof(*ab), gfp_mask);
1566 ab->gfp_mask = gfp_mask;
1568 ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
1572 nlh = nlmsg_put(ab->skb, 0, 0, type, 0, 0);
1582 audit_buffer_free(ab);
1587 * audit_serial - compute a serial number for the audit record
1589 * Compute a serial number for the audit record. Audit records are
1590 * written to user-space as soon as they are generated, so a complete
1591 * audit record may be written in several pieces. The timestamp of the
1592 * record and this serial number are used by the user-space tools to
1593 * determine which pieces belong to the same audit record. The
1594 * (timestamp,serial) tuple is unique for each syscall and is live from
1595 * syscall entry to syscall exit.
1597 * NOTE: Another possibility is to store the formatted records off the
1598 * audit context (for those records that have a context), and emit them
1599 * all at syscall exit. However, this could delay the reporting of
1600 * significant errors until syscall exit (or never, if the system
1603 unsigned int audit_serial(void)
1605 static atomic_t serial = ATOMIC_INIT(0);
1607 return atomic_add_return(1, &serial);
1610 static inline void audit_get_stamp(struct audit_context *ctx,
1611 struct timespec *t, unsigned int *serial)
1613 if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
1615 *serial = audit_serial();
1620 * audit_log_start - obtain an audit buffer
1621 * @ctx: audit_context (may be NULL)
1622 * @gfp_mask: type of allocation
1623 * @type: audit message type
1625 * Returns audit_buffer pointer on success or NULL on error.
1627 * Obtain an audit buffer. This routine does locking to obtain the
1628 * audit buffer, but then no locking is required for calls to
1629 * audit_log_*format. If the task (ctx) is a task that is currently in a
1630 * syscall, then the syscall is marked as auditable and an audit record
1631 * will be written at syscall exit. If there is no associated task, then
1632 * task context (ctx) should be NULL.
1634 struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1637 struct audit_buffer *ab;
1639 unsigned int uninitialized_var(serial);
1641 if (audit_initialized != AUDIT_INITIALIZED)
1644 if (unlikely(!audit_filter(type, AUDIT_FILTER_TYPE)))
1647 /* NOTE: don't ever fail/sleep on these two conditions:
1648 * 1. auditd generated record - since we need auditd to drain the
1649 * queue; also, when we are checking for auditd, compare PIDs using
1650 * task_tgid_vnr() since auditd_pid is set in audit_receive_msg()
1651 * using a PID anchored in the caller's namespace
1652 * 2. generator holding the audit_cmd_mutex - we don't want to block
1653 * while holding the mutex */
1654 if (!(auditd_test_task(current) ||
1655 (current == __mutex_owner(&audit_cmd_mutex)))) {
1656 long stime = audit_backlog_wait_time;
1658 while (audit_backlog_limit &&
1659 (skb_queue_len(&audit_queue) > audit_backlog_limit)) {
1660 /* wake kauditd to try and flush the queue */
1661 wake_up_interruptible(&kauditd_wait);
1663 /* sleep if we are allowed and we haven't exhausted our
1664 * backlog wait limit */
1665 if (gfpflags_allow_blocking(gfp_mask) && (stime > 0)) {
1666 DECLARE_WAITQUEUE(wait, current);
1668 add_wait_queue_exclusive(&audit_backlog_wait,
1670 set_current_state(TASK_UNINTERRUPTIBLE);
1671 stime = schedule_timeout(stime);
1672 remove_wait_queue(&audit_backlog_wait, &wait);
1674 if (audit_rate_check() && printk_ratelimit())
1675 pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
1676 skb_queue_len(&audit_queue),
1677 audit_backlog_limit);
1678 audit_log_lost("backlog limit exceeded");
1684 ab = audit_buffer_alloc(ctx, gfp_mask, type);
1686 audit_log_lost("out of memory in audit_log_start");
1690 audit_get_stamp(ab->ctx, &t, &serial);
1691 audit_log_format(ab, "audit(%lu.%03lu:%u): ",
1692 t.tv_sec, t.tv_nsec/1000000, serial);
1698 * audit_expand - expand skb in the audit buffer
1700 * @extra: space to add at tail of the skb
1702 * Returns 0 (no space) on failed expansion, or available space if
1705 static inline int audit_expand(struct audit_buffer *ab, int extra)
1707 struct sk_buff *skb = ab->skb;
1708 int oldtail = skb_tailroom(skb);
1709 int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1710 int newtail = skb_tailroom(skb);
1713 audit_log_lost("out of memory in audit_expand");
1717 skb->truesize += newtail - oldtail;
1722 * Format an audit message into the audit buffer. If there isn't enough
1723 * room in the audit buffer, more room will be allocated and vsnprint
1724 * will be called a second time. Currently, we assume that a printk
1725 * can't format message larger than 1024 bytes, so we don't either.
1727 static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1731 struct sk_buff *skb;
1739 avail = skb_tailroom(skb);
1741 avail = audit_expand(ab, AUDIT_BUFSIZ);
1745 va_copy(args2, args);
1746 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1748 /* The printk buffer is 1024 bytes long, so if we get
1749 * here and AUDIT_BUFSIZ is at least 1024, then we can
1750 * log everything that printk could have logged. */
1751 avail = audit_expand(ab,
1752 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1755 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1766 * audit_log_format - format a message into the audit buffer.
1768 * @fmt: format string
1769 * @...: optional parameters matching @fmt string
1771 * All the work is done in audit_log_vformat.
1773 void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1779 va_start(args, fmt);
1780 audit_log_vformat(ab, fmt, args);
1785 * audit_log_hex - convert a buffer to hex and append it to the audit skb
1786 * @ab: the audit_buffer
1787 * @buf: buffer to convert to hex
1788 * @len: length of @buf to be converted
1790 * No return value; failure to expand is silently ignored.
1792 * This function will take the passed buf and convert it into a string of
1793 * ascii hex digits. The new string is placed onto the skb.
1795 void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
1798 int i, avail, new_len;
1800 struct sk_buff *skb;
1807 avail = skb_tailroom(skb);
1809 if (new_len >= avail) {
1810 /* Round the buffer request up to the next multiple */
1811 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1812 avail = audit_expand(ab, new_len);
1817 ptr = skb_tail_pointer(skb);
1818 for (i = 0; i < len; i++)
1819 ptr = hex_byte_pack_upper(ptr, buf[i]);
1821 skb_put(skb, len << 1); /* new string is twice the old string */
1825 * Format a string of no more than slen characters into the audit buffer,
1826 * enclosed in quote marks.
1828 void audit_log_n_string(struct audit_buffer *ab, const char *string,
1833 struct sk_buff *skb;
1840 avail = skb_tailroom(skb);
1841 new_len = slen + 3; /* enclosing quotes + null terminator */
1842 if (new_len > avail) {
1843 avail = audit_expand(ab, new_len);
1847 ptr = skb_tail_pointer(skb);
1849 memcpy(ptr, string, slen);
1853 skb_put(skb, slen + 2); /* don't include null terminator */
1857 * audit_string_contains_control - does a string need to be logged in hex
1858 * @string: string to be checked
1859 * @len: max length of the string to check
1861 bool audit_string_contains_control(const char *string, size_t len)
1863 const unsigned char *p;
1864 for (p = string; p < (const unsigned char *)string + len; p++) {
1865 if (*p == '"' || *p < 0x21 || *p > 0x7e)
1872 * audit_log_n_untrustedstring - log a string that may contain random characters
1874 * @len: length of string (not including trailing null)
1875 * @string: string to be logged
1877 * This code will escape a string that is passed to it if the string
1878 * contains a control character, unprintable character, double quote mark,
1879 * or a space. Unescaped strings will start and end with a double quote mark.
1880 * Strings that are escaped are printed in hex (2 digits per char).
1882 * The caller specifies the number of characters in the string to log, which may
1883 * or may not be the entire string.
1885 void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
1888 if (audit_string_contains_control(string, len))
1889 audit_log_n_hex(ab, string, len);
1891 audit_log_n_string(ab, string, len);
1895 * audit_log_untrustedstring - log a string that may contain random characters
1897 * @string: string to be logged
1899 * Same as audit_log_n_untrustedstring(), except that strlen is used to
1900 * determine string length.
1902 void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
1904 audit_log_n_untrustedstring(ab, string, strlen(string));
1907 /* This is a helper-function to print the escaped d_path */
1908 void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
1909 const struct path *path)
1914 audit_log_format(ab, "%s", prefix);
1916 /* We will allow 11 spaces for ' (deleted)' to be appended */
1917 pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
1919 audit_log_string(ab, "<no_memory>");
1922 p = d_path(path, pathname, PATH_MAX+11);
1923 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
1924 /* FIXME: can we save some information here? */
1925 audit_log_string(ab, "<too_long>");
1927 audit_log_untrustedstring(ab, p);
1931 void audit_log_session_info(struct audit_buffer *ab)
1933 unsigned int sessionid = audit_get_sessionid(current);
1934 uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
1936 audit_log_format(ab, " auid=%u ses=%u", auid, sessionid);
1939 void audit_log_key(struct audit_buffer *ab, char *key)
1941 audit_log_format(ab, " key=");
1943 audit_log_untrustedstring(ab, key);
1945 audit_log_format(ab, "(null)");
1948 void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap)
1952 audit_log_format(ab, " %s=", prefix);
1953 CAP_FOR_EACH_U32(i) {
1954 audit_log_format(ab, "%08x",
1955 cap->cap[CAP_LAST_U32 - i]);
1959 static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
1961 kernel_cap_t *perm = &name->fcap.permitted;
1962 kernel_cap_t *inh = &name->fcap.inheritable;
1965 if (!cap_isclear(*perm)) {
1966 audit_log_cap(ab, "cap_fp", perm);
1969 if (!cap_isclear(*inh)) {
1970 audit_log_cap(ab, "cap_fi", inh);
1975 audit_log_format(ab, " cap_fe=%d cap_fver=%x",
1976 name->fcap.fE, name->fcap_ver);
1979 static inline int audit_copy_fcaps(struct audit_names *name,
1980 const struct dentry *dentry)
1982 struct cpu_vfs_cap_data caps;
1988 rc = get_vfs_caps_from_disk(dentry, &caps);
1992 name->fcap.permitted = caps.permitted;
1993 name->fcap.inheritable = caps.inheritable;
1994 name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
1995 name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >>
1996 VFS_CAP_REVISION_SHIFT;
2001 /* Copy inode data into an audit_names. */
2002 void audit_copy_inode(struct audit_names *name, const struct dentry *dentry,
2003 struct inode *inode)
2005 name->ino = inode->i_ino;
2006 name->dev = inode->i_sb->s_dev;
2007 name->mode = inode->i_mode;
2008 name->uid = inode->i_uid;
2009 name->gid = inode->i_gid;
2010 name->rdev = inode->i_rdev;
2011 security_inode_getsecid(inode, &name->osid);
2012 audit_copy_fcaps(name, dentry);
2016 * audit_log_name - produce AUDIT_PATH record from struct audit_names
2017 * @context: audit_context for the task
2018 * @n: audit_names structure with reportable details
2019 * @path: optional path to report instead of audit_names->name
2020 * @record_num: record number to report when handling a list of names
2021 * @call_panic: optional pointer to int that will be updated if secid fails
2023 void audit_log_name(struct audit_context *context, struct audit_names *n,
2024 const struct path *path, int record_num, int *call_panic)
2026 struct audit_buffer *ab;
2027 ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH);
2031 audit_log_format(ab, "item=%d", record_num);
2034 audit_log_d_path(ab, " name=", path);
2036 switch (n->name_len) {
2037 case AUDIT_NAME_FULL:
2038 /* log the full path */
2039 audit_log_format(ab, " name=");
2040 audit_log_untrustedstring(ab, n->name->name);
2043 /* name was specified as a relative path and the
2044 * directory component is the cwd */
2045 audit_log_d_path(ab, " name=", &context->pwd);
2048 /* log the name's directory component */
2049 audit_log_format(ab, " name=");
2050 audit_log_n_untrustedstring(ab, n->name->name,
2054 audit_log_format(ab, " name=(null)");
2056 if (n->ino != AUDIT_INO_UNSET)
2057 audit_log_format(ab, " inode=%lu"
2058 " dev=%02x:%02x mode=%#ho"
2059 " ouid=%u ogid=%u rdev=%02x:%02x",
2064 from_kuid(&init_user_ns, n->uid),
2065 from_kgid(&init_user_ns, n->gid),
2071 if (security_secid_to_secctx(
2072 n->osid, &ctx, &len)) {
2073 audit_log_format(ab, " osid=%u", n->osid);
2077 audit_log_format(ab, " obj=%s", ctx);
2078 security_release_secctx(ctx, len);
2082 /* log the audit_names record type */
2083 audit_log_format(ab, " nametype=");
2085 case AUDIT_TYPE_NORMAL:
2086 audit_log_format(ab, "NORMAL");
2088 case AUDIT_TYPE_PARENT:
2089 audit_log_format(ab, "PARENT");
2091 case AUDIT_TYPE_CHILD_DELETE:
2092 audit_log_format(ab, "DELETE");
2094 case AUDIT_TYPE_CHILD_CREATE:
2095 audit_log_format(ab, "CREATE");
2098 audit_log_format(ab, "UNKNOWN");
2102 audit_log_fcaps(ab, n);
2106 int audit_log_task_context(struct audit_buffer *ab)
2113 security_task_getsecid(current, &sid);
2117 error = security_secid_to_secctx(sid, &ctx, &len);
2119 if (error != -EINVAL)
2124 audit_log_format(ab, " subj=%s", ctx);
2125 security_release_secctx(ctx, len);
2129 audit_panic("error in audit_log_task_context");
2132 EXPORT_SYMBOL(audit_log_task_context);
2134 void audit_log_d_path_exe(struct audit_buffer *ab,
2135 struct mm_struct *mm)
2137 struct file *exe_file;
2142 exe_file = get_mm_exe_file(mm);
2146 audit_log_d_path(ab, " exe=", &exe_file->f_path);
2150 audit_log_format(ab, " exe=(null)");
2153 struct tty_struct *audit_get_tty(struct task_struct *tsk)
2155 struct tty_struct *tty = NULL;
2156 unsigned long flags;
2158 spin_lock_irqsave(&tsk->sighand->siglock, flags);
2160 tty = tty_kref_get(tsk->signal->tty);
2161 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
2165 void audit_put_tty(struct tty_struct *tty)
2170 void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
2172 const struct cred *cred;
2173 char comm[sizeof(tsk->comm)];
2174 struct tty_struct *tty;
2179 /* tsk == current */
2180 cred = current_cred();
2181 tty = audit_get_tty(tsk);
2182 audit_log_format(ab,
2183 " ppid=%d pid=%d auid=%u uid=%u gid=%u"
2184 " euid=%u suid=%u fsuid=%u"
2185 " egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
2188 from_kuid(&init_user_ns, audit_get_loginuid(tsk)),
2189 from_kuid(&init_user_ns, cred->uid),
2190 from_kgid(&init_user_ns, cred->gid),
2191 from_kuid(&init_user_ns, cred->euid),
2192 from_kuid(&init_user_ns, cred->suid),
2193 from_kuid(&init_user_ns, cred->fsuid),
2194 from_kgid(&init_user_ns, cred->egid),
2195 from_kgid(&init_user_ns, cred->sgid),
2196 from_kgid(&init_user_ns, cred->fsgid),
2197 tty ? tty_name(tty) : "(none)",
2198 audit_get_sessionid(tsk));
2200 audit_log_format(ab, " comm=");
2201 audit_log_untrustedstring(ab, get_task_comm(comm, tsk));
2202 audit_log_d_path_exe(ab, tsk->mm);
2203 audit_log_task_context(ab);
2205 EXPORT_SYMBOL(audit_log_task_info);
2208 * audit_log_link_denied - report a link restriction denial
2209 * @operation: specific link operation
2210 * @link: the path that triggered the restriction
2212 void audit_log_link_denied(const char *operation, const struct path *link)
2214 struct audit_buffer *ab;
2215 struct audit_names *name;
2217 name = kzalloc(sizeof(*name), GFP_NOFS);
2221 /* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */
2222 ab = audit_log_start(current->audit_context, GFP_KERNEL,
2226 audit_log_format(ab, "op=%s", operation);
2227 audit_log_task_info(ab, current);
2228 audit_log_format(ab, " res=0");
2231 /* Generate AUDIT_PATH record with object. */
2232 name->type = AUDIT_TYPE_NORMAL;
2233 audit_copy_inode(name, link->dentry, d_backing_inode(link->dentry));
2234 audit_log_name(current->audit_context, name, link, 0, NULL);
2240 * audit_log_end - end one audit record
2241 * @ab: the audit_buffer
2243 * We can not do a netlink send inside an irq context because it blocks (last
2244 * arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a
2245 * queue and a tasklet is scheduled to remove them from the queue outside the
2246 * irq context. May be called in any context.
2248 void audit_log_end(struct audit_buffer *ab)
2250 struct sk_buff *skb;
2251 struct nlmsghdr *nlh;
2256 if (audit_rate_check()) {
2260 /* setup the netlink header, see the comments in
2261 * kauditd_send_multicast_skb() for length quirks */
2262 nlh = nlmsg_hdr(skb);
2263 nlh->nlmsg_len = skb->len - NLMSG_HDRLEN;
2265 /* queue the netlink packet and poke the kauditd thread */
2266 skb_queue_tail(&audit_queue, skb);
2267 wake_up_interruptible(&kauditd_wait);
2269 audit_log_lost("rate limit exceeded");
2271 audit_buffer_free(ab);
2275 * audit_log - Log an audit record
2276 * @ctx: audit context
2277 * @gfp_mask: type of allocation
2278 * @type: audit message type
2279 * @fmt: format string to use
2280 * @...: variable parameters matching the format string
2282 * This is a convenience function that calls audit_log_start,
2283 * audit_log_vformat, and audit_log_end. It may be called
2286 void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
2287 const char *fmt, ...)
2289 struct audit_buffer *ab;
2292 ab = audit_log_start(ctx, gfp_mask, type);
2294 va_start(args, fmt);
2295 audit_log_vformat(ab, fmt, args);
2301 #ifdef CONFIG_SECURITY
2303 * audit_log_secctx - Converts and logs SELinux context
2305 * @secid: security number
2307 * This is a helper function that calls security_secid_to_secctx to convert
2308 * secid to secctx and then adds the (converted) SELinux context to the audit
2309 * log by calling audit_log_format, thus also preventing leak of internal secid
2310 * to userspace. If secid cannot be converted audit_panic is called.
2312 void audit_log_secctx(struct audit_buffer *ab, u32 secid)
2317 if (security_secid_to_secctx(secid, &secctx, &len)) {
2318 audit_panic("Cannot convert secid to context");
2320 audit_log_format(ab, " obj=%s", secctx);
2321 security_release_secctx(secctx, len);
2324 EXPORT_SYMBOL(audit_log_secctx);
2327 EXPORT_SYMBOL(audit_log_start);
2328 EXPORT_SYMBOL(audit_log_end);
2329 EXPORT_SYMBOL(audit_log_format);
2330 EXPORT_SYMBOL(audit_log);