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>
61 #include <linux/pid.h>
62 #include <linux/slab.h>
64 #include <linux/audit.h>
67 #include <net/netlink.h>
68 #include <linux/skbuff.h>
69 #ifdef CONFIG_SECURITY
70 #include <linux/security.h>
72 #include <linux/freezer.h>
73 #include <linux/pid_namespace.h>
74 #include <net/netns/generic.h>
78 /* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
79 * (Initialization happens after skb_init is called.) */
80 #define AUDIT_DISABLED -1
81 #define AUDIT_UNINITIALIZED 0
82 #define AUDIT_INITIALIZED 1
83 static int audit_initialized;
87 #define AUDIT_LOCKED 2
88 u32 audit_enabled = AUDIT_OFF;
89 u32 audit_ever_enabled = !!AUDIT_OFF;
91 EXPORT_SYMBOL_GPL(audit_enabled);
93 /* Default state when kernel boots without any parameters. */
94 static u32 audit_default = AUDIT_OFF;
96 /* If auditing cannot proceed, audit_failure selects what happens. */
97 static u32 audit_failure = AUDIT_FAIL_PRINTK;
99 /* private audit network namespace index */
100 static unsigned int audit_net_id;
103 * struct audit_net - audit private network namespace data
104 * @sk: communication socket
111 * struct auditd_connection - kernel/auditd connection state
113 * @portid: netlink portid
114 * @net: the associated network namespace
118 * This struct is RCU protected; you must either hold the RCU lock for reading
119 * or the associated spinlock for writing.
121 static struct auditd_connection {
126 } *auditd_conn = NULL;
127 static DEFINE_SPINLOCK(auditd_conn_lock);
129 /* If audit_rate_limit is non-zero, limit the rate of sending audit records
130 * to that number per second. This prevents DoS attacks, but results in
131 * audit records being dropped. */
132 static u32 audit_rate_limit;
134 /* Number of outstanding audit_buffers allowed.
135 * When set to zero, this means unlimited. */
136 static u32 audit_backlog_limit = 64;
137 #define AUDIT_BACKLOG_WAIT_TIME (60 * HZ)
138 static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
140 /* The identity of the user shutting down the audit system. */
141 kuid_t audit_sig_uid = INVALID_UID;
142 pid_t audit_sig_pid = -1;
143 u32 audit_sig_sid = 0;
145 /* Records can be lost in several ways:
146 0) [suppressed in audit_alloc]
147 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
148 2) out of memory in audit_log_move [alloc_skb]
149 3) suppressed due to audit_rate_limit
150 4) suppressed due to audit_backlog_limit
152 static atomic_t audit_lost = ATOMIC_INIT(0);
154 /* Hash for inode-based rules */
155 struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
157 static struct kmem_cache *audit_buffer_cache;
159 /* queue msgs to send via kauditd_task */
160 static struct sk_buff_head audit_queue;
161 /* queue msgs due to temporary unicast send problems */
162 static struct sk_buff_head audit_retry_queue;
163 /* queue msgs waiting for new auditd connection */
164 static struct sk_buff_head audit_hold_queue;
166 /* queue servicing thread */
167 static struct task_struct *kauditd_task;
168 static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
170 /* waitqueue for callers who are blocked on the audit backlog */
171 static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
173 static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION,
178 static char *audit_feature_names[2] = {
179 "only_unset_loginuid",
180 "loginuid_immutable",
184 /* Serialize requests from userspace. */
185 DEFINE_MUTEX(audit_cmd_mutex);
187 /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
188 * audit records. Since printk uses a 1024 byte buffer, this buffer
189 * should be at least that large. */
190 #define AUDIT_BUFSIZ 1024
192 /* The audit_buffer is used when formatting an audit record. The caller
193 * locks briefly to get the record off the freelist or to allocate the
194 * buffer, and locks briefly to send the buffer to the netlink layer or
195 * to place it on a transmit queue. Multiple audit_buffers can be in
196 * use simultaneously. */
197 struct audit_buffer {
198 struct sk_buff *skb; /* formatted skb ready to send */
199 struct audit_context *ctx; /* NULL or associated context */
210 * auditd_test_task - Check to see if a given task is an audit daemon
211 * @task: the task to check
214 * Return 1 if the task is a registered audit daemon, 0 otherwise.
216 int auditd_test_task(struct task_struct *task)
219 struct auditd_connection *ac;
222 ac = rcu_dereference(auditd_conn);
223 rc = (ac && ac->pid == task_tgid(task) ? 1 : 0);
230 * auditd_pid_vnr - Return the auditd PID relative to the namespace
233 * Returns the PID in relation to the namespace, 0 on failure.
235 static pid_t auditd_pid_vnr(void)
238 const struct auditd_connection *ac;
241 ac = rcu_dereference(auditd_conn);
245 pid = pid_vnr(ac->pid);
252 * audit_get_sk - Return the audit socket for the given network namespace
253 * @net: the destination network namespace
256 * Returns the sock pointer if valid, NULL otherwise. The caller must ensure
257 * that a reference is held for the network namespace while the sock is in use.
259 static struct sock *audit_get_sk(const struct net *net)
261 struct audit_net *aunet;
266 aunet = net_generic(net, audit_net_id);
270 void audit_panic(const char *message)
272 switch (audit_failure) {
273 case AUDIT_FAIL_SILENT:
275 case AUDIT_FAIL_PRINTK:
276 if (printk_ratelimit())
277 pr_err("%s\n", message);
279 case AUDIT_FAIL_PANIC:
280 panic("audit: %s\n", message);
285 static inline int audit_rate_check(void)
287 static unsigned long last_check = 0;
288 static int messages = 0;
289 static DEFINE_SPINLOCK(lock);
292 unsigned long elapsed;
295 if (!audit_rate_limit) return 1;
297 spin_lock_irqsave(&lock, flags);
298 if (++messages < audit_rate_limit) {
302 elapsed = now - last_check;
309 spin_unlock_irqrestore(&lock, flags);
315 * audit_log_lost - conditionally log lost audit message event
316 * @message: the message stating reason for lost audit message
318 * Emit at least 1 message per second, even if audit_rate_check is
320 * Always increment the lost messages counter.
322 void audit_log_lost(const char *message)
324 static unsigned long last_msg = 0;
325 static DEFINE_SPINLOCK(lock);
330 atomic_inc(&audit_lost);
332 print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
335 spin_lock_irqsave(&lock, flags);
337 if (now - last_msg > HZ) {
341 spin_unlock_irqrestore(&lock, flags);
345 if (printk_ratelimit())
346 pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
347 atomic_read(&audit_lost),
349 audit_backlog_limit);
350 audit_panic(message);
354 static int audit_log_config_change(char *function_name, u32 new, u32 old,
357 struct audit_buffer *ab;
360 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
363 audit_log_format(ab, "%s=%u old=%u", function_name, new, old);
364 audit_log_session_info(ab);
365 rc = audit_log_task_context(ab);
367 allow_changes = 0; /* Something weird, deny request */
368 audit_log_format(ab, " res=%d", allow_changes);
373 static int audit_do_config_change(char *function_name, u32 *to_change, u32 new)
375 int allow_changes, rc = 0;
376 u32 old = *to_change;
378 /* check if we are locked */
379 if (audit_enabled == AUDIT_LOCKED)
384 if (audit_enabled != AUDIT_OFF) {
385 rc = audit_log_config_change(function_name, new, old, allow_changes);
390 /* If we are allowed, make the change */
391 if (allow_changes == 1)
393 /* Not allowed, update reason */
399 static int audit_set_rate_limit(u32 limit)
401 return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit);
404 static int audit_set_backlog_limit(u32 limit)
406 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit);
409 static int audit_set_backlog_wait_time(u32 timeout)
411 return audit_do_config_change("audit_backlog_wait_time",
412 &audit_backlog_wait_time, timeout);
415 static int audit_set_enabled(u32 state)
418 if (state > AUDIT_LOCKED)
421 rc = audit_do_config_change("audit_enabled", &audit_enabled, state);
423 audit_ever_enabled |= !!state;
428 static int audit_set_failure(u32 state)
430 if (state != AUDIT_FAIL_SILENT
431 && state != AUDIT_FAIL_PRINTK
432 && state != AUDIT_FAIL_PANIC)
435 return audit_do_config_change("audit_failure", &audit_failure, state);
439 * auditd_conn_free - RCU helper to release an auditd connection struct
443 * Drop any references inside the auditd connection tracking struct and free
446 static void auditd_conn_free(struct rcu_head *rcu)
448 struct auditd_connection *ac;
450 ac = container_of(rcu, struct auditd_connection, rcu);
457 * auditd_set - Set/Reset the auditd connection state
459 * @portid: auditd netlink portid
460 * @net: auditd network namespace pointer
463 * This function will obtain and drop network namespace references as
464 * necessary. Returns zero on success, negative values on failure.
466 static int auditd_set(struct pid *pid, u32 portid, struct net *net)
469 struct auditd_connection *ac_old, *ac_new;
474 ac_new = kzalloc(sizeof(*ac_new), GFP_KERNEL);
477 ac_new->pid = get_pid(pid);
478 ac_new->portid = portid;
479 ac_new->net = get_net(net);
481 spin_lock_irqsave(&auditd_conn_lock, flags);
482 ac_old = rcu_dereference_protected(auditd_conn,
483 lockdep_is_held(&auditd_conn_lock));
484 rcu_assign_pointer(auditd_conn, ac_new);
485 spin_unlock_irqrestore(&auditd_conn_lock, flags);
488 call_rcu(&ac_old->rcu, auditd_conn_free);
494 * kauditd_print_skb - Print the audit record to the ring buffer
497 * Whatever the reason, this packet may not make it to the auditd connection
498 * so write it via printk so the information isn't completely lost.
500 static void kauditd_printk_skb(struct sk_buff *skb)
502 struct nlmsghdr *nlh = nlmsg_hdr(skb);
503 char *data = nlmsg_data(nlh);
505 if (nlh->nlmsg_type != AUDIT_EOE && printk_ratelimit())
506 pr_notice("type=%d %s\n", nlh->nlmsg_type, data);
510 * kauditd_rehold_skb - Handle a audit record send failure in the hold queue
514 * This should only be used by the kauditd_thread when it fails to flush the
517 static void kauditd_rehold_skb(struct sk_buff *skb)
519 /* put the record back in the queue at the same place */
520 skb_queue_head(&audit_hold_queue, skb);
524 * kauditd_hold_skb - Queue an audit record, waiting for auditd
528 * Queue the audit record, waiting for an instance of auditd. When this
529 * function is called we haven't given up yet on sending the record, but things
530 * are not looking good. The first thing we want to do is try to write the
531 * record via printk and then see if we want to try and hold on to the record
532 * and queue it, if we have room. If we want to hold on to the record, but we
533 * don't have room, record a record lost message.
535 static void kauditd_hold_skb(struct sk_buff *skb)
537 /* at this point it is uncertain if we will ever send this to auditd so
538 * try to send the message via printk before we go any further */
539 kauditd_printk_skb(skb);
541 /* can we just silently drop the message? */
542 if (!audit_default) {
547 /* if we have room, queue the message */
548 if (!audit_backlog_limit ||
549 skb_queue_len(&audit_hold_queue) < audit_backlog_limit) {
550 skb_queue_tail(&audit_hold_queue, skb);
554 /* we have no other options - drop the message */
555 audit_log_lost("kauditd hold queue overflow");
560 * kauditd_retry_skb - Queue an audit record, attempt to send again to auditd
564 * Not as serious as kauditd_hold_skb() as we still have a connected auditd,
565 * but for some reason we are having problems sending it audit records so
566 * queue the given record and attempt to resend.
568 static void kauditd_retry_skb(struct sk_buff *skb)
570 /* NOTE: because records should only live in the retry queue for a
571 * short period of time, before either being sent or moved to the hold
572 * queue, we don't currently enforce a limit on this queue */
573 skb_queue_tail(&audit_retry_queue, skb);
577 * auditd_reset - Disconnect the auditd connection
578 * @ac: auditd connection state
581 * Break the auditd/kauditd connection and move all the queued records into the
582 * hold queue in case auditd reconnects. It is important to note that the @ac
583 * pointer should never be dereferenced inside this function as it may be NULL
584 * or invalid, you can only compare the memory address! If @ac is NULL then
585 * the connection will always be reset.
587 static void auditd_reset(const struct auditd_connection *ac)
591 struct auditd_connection *ac_old;
593 /* if it isn't already broken, break the connection */
594 spin_lock_irqsave(&auditd_conn_lock, flags);
595 ac_old = rcu_dereference_protected(auditd_conn,
596 lockdep_is_held(&auditd_conn_lock));
597 if (ac && ac != ac_old) {
598 /* someone already registered a new auditd connection */
599 spin_unlock_irqrestore(&auditd_conn_lock, flags);
602 rcu_assign_pointer(auditd_conn, NULL);
603 spin_unlock_irqrestore(&auditd_conn_lock, flags);
606 call_rcu(&ac_old->rcu, auditd_conn_free);
608 /* flush the retry queue to the hold queue, but don't touch the main
609 * queue since we need to process that normally for multicast */
610 while ((skb = skb_dequeue(&audit_retry_queue)))
611 kauditd_hold_skb(skb);
615 * auditd_send_unicast_skb - Send a record via unicast to auditd
619 * Send a skb to the audit daemon, returns positive/zero values on success and
620 * negative values on failure; in all cases the skb will be consumed by this
621 * function. If the send results in -ECONNREFUSED the connection with auditd
622 * will be reset. This function may sleep so callers should not hold any locks
623 * where this would cause a problem.
625 static int auditd_send_unicast_skb(struct sk_buff *skb)
631 struct auditd_connection *ac;
633 /* NOTE: we can't call netlink_unicast while in the RCU section so
634 * take a reference to the network namespace and grab local
635 * copies of the namespace, the sock, and the portid; the
636 * namespace and sock aren't going to go away while we hold a
637 * reference and if the portid does become invalid after the RCU
638 * section netlink_unicast() should safely return an error */
641 ac = rcu_dereference(auditd_conn);
648 net = get_net(ac->net);
649 sk = audit_get_sk(net);
653 rc = netlink_unicast(sk, skb, portid, 0);
661 if (ac && rc == -ECONNREFUSED)
667 * kauditd_send_queue - Helper for kauditd_thread to flush skb queues
668 * @sk: the sending sock
669 * @portid: the netlink destination
670 * @queue: the skb queue to process
671 * @retry_limit: limit on number of netlink unicast failures
672 * @skb_hook: per-skb hook for additional processing
673 * @err_hook: hook called if the skb fails the netlink unicast send
676 * Run through the given queue and attempt to send the audit records to auditd,
677 * returns zero on success, negative values on failure. It is up to the caller
678 * to ensure that the @sk is valid for the duration of this function.
681 static int kauditd_send_queue(struct sock *sk, u32 portid,
682 struct sk_buff_head *queue,
683 unsigned int retry_limit,
684 void (*skb_hook)(struct sk_buff *skb),
685 void (*err_hook)(struct sk_buff *skb))
689 static unsigned int failed = 0;
691 /* NOTE: kauditd_thread takes care of all our locking, we just use
692 * the netlink info passed to us (e.g. sk and portid) */
694 while ((skb = skb_dequeue(queue))) {
695 /* call the skb_hook for each skb we touch */
699 /* can we send to anyone via unicast? */
706 /* grab an extra skb reference in case of error */
708 rc = netlink_unicast(sk, skb, portid, 0);
710 /* fatal failure for our queue flush attempt? */
711 if (++failed >= retry_limit ||
712 rc == -ECONNREFUSED || rc == -EPERM) {
713 /* yes - error processing for the queue */
719 /* keep processing with the skb_hook */
722 /* no - requeue to preserve ordering */
723 skb_queue_head(queue, skb);
725 /* it worked - drop the extra reference and continue */
732 return (rc >= 0 ? 0 : rc);
736 * kauditd_send_multicast_skb - Send a record to any multicast listeners
740 * Write a multicast message to anyone listening in the initial network
741 * namespace. This function doesn't consume an skb as might be expected since
742 * it has to copy it anyways.
744 static void kauditd_send_multicast_skb(struct sk_buff *skb)
746 struct sk_buff *copy;
747 struct sock *sock = audit_get_sk(&init_net);
748 struct nlmsghdr *nlh;
750 /* NOTE: we are not taking an additional reference for init_net since
751 * we don't have to worry about it going away */
753 if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
757 * The seemingly wasteful skb_copy() rather than bumping the refcount
758 * using skb_get() is necessary because non-standard mods are made to
759 * the skb by the original kaudit unicast socket send routine. The
760 * existing auditd daemon assumes this breakage. Fixing this would
761 * require co-ordinating a change in the established protocol between
762 * the kaudit kernel subsystem and the auditd userspace code. There is
763 * no reason for new multicast clients to continue with this
766 copy = skb_copy(skb, GFP_KERNEL);
769 nlh = nlmsg_hdr(copy);
770 nlh->nlmsg_len = skb->len;
772 nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL);
776 * kauditd_thread - Worker thread to send audit records to userspace
779 static int kauditd_thread(void *dummy)
783 struct net *net = NULL;
784 struct sock *sk = NULL;
785 struct auditd_connection *ac;
787 #define UNICAST_RETRIES 5
790 while (!kthread_should_stop()) {
791 /* NOTE: see the lock comments in auditd_send_unicast_skb() */
793 ac = rcu_dereference(auditd_conn);
798 net = get_net(ac->net);
799 sk = audit_get_sk(net);
803 /* attempt to flush the hold queue */
804 rc = kauditd_send_queue(sk, portid,
805 &audit_hold_queue, UNICAST_RETRIES,
806 NULL, kauditd_rehold_skb);
813 /* attempt to flush the retry queue */
814 rc = kauditd_send_queue(sk, portid,
815 &audit_retry_queue, UNICAST_RETRIES,
816 NULL, kauditd_hold_skb);
824 /* process the main queue - do the multicast send and attempt
825 * unicast, dump failed record sends to the retry queue; if
826 * sk == NULL due to previous failures we will just do the
827 * multicast send and move the record to the hold queue */
828 rc = kauditd_send_queue(sk, portid, &audit_queue, 1,
829 kauditd_send_multicast_skb,
831 kauditd_retry_skb : kauditd_hold_skb));
836 /* drop our netns reference, no auditd sends past this line */
842 /* we have processed all the queues so wake everyone */
843 wake_up(&audit_backlog_wait);
845 /* NOTE: we want to wake up if there is anything on the queue,
846 * regardless of if an auditd is connected, as we need to
847 * do the multicast send and rotate records from the
848 * main queue to the retry/hold queues */
849 wait_event_freezable(kauditd_wait,
850 (skb_queue_len(&audit_queue) ? 1 : 0));
856 int audit_send_list_thread(void *_dest)
858 struct audit_netlink_list *dest = _dest;
860 struct sock *sk = audit_get_sk(dest->net);
862 /* wait for parent to finish and send an ACK */
863 mutex_lock(&audit_cmd_mutex);
864 mutex_unlock(&audit_cmd_mutex);
866 while ((skb = __skb_dequeue(&dest->q)) != NULL)
867 netlink_unicast(sk, skb, dest->portid, 0);
875 struct sk_buff *audit_make_reply(int seq, int type, int done,
876 int multi, const void *payload, int size)
879 struct nlmsghdr *nlh;
881 int flags = multi ? NLM_F_MULTI : 0;
882 int t = done ? NLMSG_DONE : type;
884 skb = nlmsg_new(size, GFP_KERNEL);
888 nlh = nlmsg_put(skb, 0, seq, t, size, flags);
891 data = nlmsg_data(nlh);
892 memcpy(data, payload, size);
900 static void audit_free_reply(struct audit_reply *reply)
906 kfree_skb(reply->skb);
912 static int audit_send_reply_thread(void *arg)
914 struct audit_reply *reply = (struct audit_reply *)arg;
916 mutex_lock(&audit_cmd_mutex);
917 mutex_unlock(&audit_cmd_mutex);
919 /* Ignore failure. It'll only happen if the sender goes away,
920 because our timeout is set to infinite. */
921 netlink_unicast(audit_get_sk(reply->net), reply->skb, reply->portid, 0);
923 audit_free_reply(reply);
928 * audit_send_reply - send an audit reply message via netlink
929 * @request_skb: skb of request we are replying to (used to target the reply)
930 * @seq: sequence number
931 * @type: audit message type
932 * @done: done (last) flag
933 * @multi: multi-part message flag
934 * @payload: payload data
935 * @size: payload size
937 * Allocates a skb, builds the netlink message, and sends it to the port id.
939 static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
940 int multi, const void *payload, int size)
942 struct task_struct *tsk;
943 struct audit_reply *reply;
945 reply = kzalloc(sizeof(*reply), GFP_KERNEL);
949 reply->skb = audit_make_reply(seq, type, done, multi, payload, size);
952 reply->net = get_net(sock_net(NETLINK_CB(request_skb).sk));
953 reply->portid = NETLINK_CB(request_skb).portid;
955 tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
962 audit_free_reply(reply);
966 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
969 static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
973 /* Only support initial user namespace for now. */
975 * We return ECONNREFUSED because it tricks userspace into thinking
976 * that audit was not configured into the kernel. Lots of users
977 * configure their PAM stack (because that's what the distro does)
978 * to reject login if unable to send messages to audit. If we return
979 * ECONNREFUSED the PAM stack thinks the kernel does not have audit
980 * configured in and will let login proceed. If we return EPERM
981 * userspace will reject all logins. This should be removed when we
982 * support non init namespaces!!
984 if (current_user_ns() != &init_user_ns)
985 return -ECONNREFUSED;
994 case AUDIT_GET_FEATURE:
995 case AUDIT_SET_FEATURE:
996 case AUDIT_LIST_RULES:
999 case AUDIT_SIGNAL_INFO:
1003 case AUDIT_MAKE_EQUIV:
1004 /* Only support auditd and auditctl in initial pid namespace
1006 if (task_active_pid_ns(current) != &init_pid_ns)
1009 if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
1013 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1014 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1015 if (!netlink_capable(skb, CAP_AUDIT_WRITE))
1018 default: /* bad msg */
1025 static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
1027 uid_t uid = from_kuid(&init_user_ns, current_uid());
1028 pid_t pid = task_tgid_nr(current);
1030 if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
1035 *ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
1038 audit_log_format(*ab, "pid=%d uid=%u", pid, uid);
1039 audit_log_session_info(*ab);
1040 audit_log_task_context(*ab);
1043 int is_audit_feature_set(int i)
1045 return af.features & AUDIT_FEATURE_TO_MASK(i);
1049 static int audit_get_feature(struct sk_buff *skb)
1053 seq = nlmsg_hdr(skb)->nlmsg_seq;
1055 audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af));
1060 static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
1061 u32 old_lock, u32 new_lock, int res)
1063 struct audit_buffer *ab;
1065 if (audit_enabled == AUDIT_OFF)
1068 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_FEATURE_CHANGE);
1071 audit_log_task_info(ab, current);
1072 audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
1073 audit_feature_names[which], !!old_feature, !!new_feature,
1074 !!old_lock, !!new_lock, res);
1078 static int audit_set_feature(struct audit_features *uaf)
1082 BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
1084 /* if there is ever a version 2 we should handle that here */
1086 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1087 u32 feature = AUDIT_FEATURE_TO_MASK(i);
1088 u32 old_feature, new_feature, old_lock, new_lock;
1090 /* if we are not changing this feature, move along */
1091 if (!(feature & uaf->mask))
1094 old_feature = af.features & feature;
1095 new_feature = uaf->features & feature;
1096 new_lock = (uaf->lock | af.lock) & feature;
1097 old_lock = af.lock & feature;
1099 /* are we changing a locked feature? */
1100 if (old_lock && (new_feature != old_feature)) {
1101 audit_log_feature_change(i, old_feature, new_feature,
1102 old_lock, new_lock, 0);
1106 /* nothing invalid, do the changes */
1107 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1108 u32 feature = AUDIT_FEATURE_TO_MASK(i);
1109 u32 old_feature, new_feature, old_lock, new_lock;
1111 /* if we are not changing this feature, move along */
1112 if (!(feature & uaf->mask))
1115 old_feature = af.features & feature;
1116 new_feature = uaf->features & feature;
1117 old_lock = af.lock & feature;
1118 new_lock = (uaf->lock | af.lock) & feature;
1120 if (new_feature != old_feature)
1121 audit_log_feature_change(i, old_feature, new_feature,
1122 old_lock, new_lock, 1);
1125 af.features |= feature;
1127 af.features &= ~feature;
1128 af.lock |= new_lock;
1134 static int audit_replace(struct pid *pid)
1137 struct sk_buff *skb;
1139 pvnr = pid_vnr(pid);
1140 skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pvnr, sizeof(pvnr));
1143 return auditd_send_unicast_skb(skb);
1146 static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
1152 struct audit_buffer *ab;
1153 u16 msg_type = nlh->nlmsg_type;
1154 struct audit_sig_info *sig_data;
1158 err = audit_netlink_ok(skb, msg_type);
1162 seq = nlh->nlmsg_seq;
1163 data = nlmsg_data(nlh);
1164 data_len = nlmsg_len(nlh);
1168 struct audit_status s;
1169 memset(&s, 0, sizeof(s));
1170 s.enabled = audit_enabled;
1171 s.failure = audit_failure;
1172 /* NOTE: use pid_vnr() so the PID is relative to the current
1174 s.pid = auditd_pid_vnr();
1175 s.rate_limit = audit_rate_limit;
1176 s.backlog_limit = audit_backlog_limit;
1177 s.lost = atomic_read(&audit_lost);
1178 s.backlog = skb_queue_len(&audit_queue);
1179 s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL;
1180 s.backlog_wait_time = audit_backlog_wait_time;
1181 audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
1185 struct audit_status s;
1186 memset(&s, 0, sizeof(s));
1187 /* guard against past and future API changes */
1188 memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
1189 if (s.mask & AUDIT_STATUS_ENABLED) {
1190 err = audit_set_enabled(s.enabled);
1194 if (s.mask & AUDIT_STATUS_FAILURE) {
1195 err = audit_set_failure(s.failure);
1199 if (s.mask & AUDIT_STATUS_PID) {
1200 /* NOTE: we are using the vnr PID functions below
1201 * because the s.pid value is relative to the
1202 * namespace of the caller; at present this
1203 * doesn't matter much since you can really only
1204 * run auditd from the initial pid namespace, but
1205 * something to keep in mind if this changes */
1206 pid_t new_pid = s.pid;
1208 struct pid *req_pid = task_tgid(current);
1210 /* Sanity check - PID values must match. Setting
1211 * pid to 0 is how auditd ends auditing. */
1212 if (new_pid && (new_pid != pid_vnr(req_pid)))
1215 /* test the auditd connection */
1216 audit_replace(req_pid);
1218 auditd_pid = auditd_pid_vnr();
1220 /* replacing a healthy auditd is not allowed */
1222 audit_log_config_change("audit_pid",
1223 new_pid, auditd_pid, 0);
1226 /* only current auditd can unregister itself */
1227 if (pid_vnr(req_pid) != auditd_pid) {
1228 audit_log_config_change("audit_pid",
1229 new_pid, auditd_pid, 0);
1235 /* register a new auditd connection */
1236 err = auditd_set(req_pid,
1237 NETLINK_CB(skb).portid,
1238 sock_net(NETLINK_CB(skb).sk));
1239 if (audit_enabled != AUDIT_OFF)
1240 audit_log_config_change("audit_pid",
1247 /* try to process any backlog */
1248 wake_up_interruptible(&kauditd_wait);
1250 if (audit_enabled != AUDIT_OFF)
1251 audit_log_config_change("audit_pid",
1255 /* unregister the auditd connection */
1259 if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
1260 err = audit_set_rate_limit(s.rate_limit);
1264 if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
1265 err = audit_set_backlog_limit(s.backlog_limit);
1269 if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
1270 if (sizeof(s) > (size_t)nlh->nlmsg_len)
1272 if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
1274 err = audit_set_backlog_wait_time(s.backlog_wait_time);
1278 if (s.mask == AUDIT_STATUS_LOST) {
1279 u32 lost = atomic_xchg(&audit_lost, 0);
1281 audit_log_config_change("lost", 0, lost, 1);
1286 case AUDIT_GET_FEATURE:
1287 err = audit_get_feature(skb);
1291 case AUDIT_SET_FEATURE:
1292 if (data_len < sizeof(struct audit_features))
1294 err = audit_set_feature(data);
1299 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1300 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1301 if (!audit_enabled && msg_type != AUDIT_USER_AVC)
1303 /* exit early if there isn't at least one character to print */
1307 err = audit_filter(msg_type, AUDIT_FILTER_USER);
1308 if (err == 1) { /* match or error */
1312 if (msg_type == AUDIT_USER_TTY) {
1313 err = tty_audit_push();
1317 audit_log_common_recv_msg(&ab, msg_type);
1318 if (msg_type != AUDIT_USER_TTY) {
1319 /* ensure NULL termination */
1320 str[data_len - 1] = '\0';
1321 audit_log_format(ab, " msg='%.*s'",
1322 AUDIT_MESSAGE_TEXT_MAX,
1325 audit_log_format(ab, " data=");
1326 if (data_len > 0 && str[data_len - 1] == '\0')
1328 audit_log_n_untrustedstring(ab, str, data_len);
1333 case AUDIT_ADD_RULE:
1334 case AUDIT_DEL_RULE:
1335 if (data_len < sizeof(struct audit_rule_data))
1337 if (audit_enabled == AUDIT_LOCKED) {
1338 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1339 audit_log_format(ab, " audit_enabled=%d res=0", audit_enabled);
1343 err = audit_rule_change(msg_type, seq, data, data_len);
1345 case AUDIT_LIST_RULES:
1346 err = audit_list_rules_send(skb, seq);
1350 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1351 audit_log_format(ab, " op=trim res=1");
1354 case AUDIT_MAKE_EQUIV: {
1357 size_t msglen = data_len;
1361 if (msglen < 2 * sizeof(u32))
1363 memcpy(sizes, bufp, 2 * sizeof(u32));
1364 bufp += 2 * sizeof(u32);
1365 msglen -= 2 * sizeof(u32);
1366 old = audit_unpack_string(&bufp, &msglen, sizes[0]);
1371 new = audit_unpack_string(&bufp, &msglen, sizes[1]);
1377 /* OK, here comes... */
1378 err = audit_tag_tree(old, new);
1380 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1382 audit_log_format(ab, " op=make_equiv old=");
1383 audit_log_untrustedstring(ab, old);
1384 audit_log_format(ab, " new=");
1385 audit_log_untrustedstring(ab, new);
1386 audit_log_format(ab, " res=%d", !err);
1392 case AUDIT_SIGNAL_INFO:
1394 if (audit_sig_sid) {
1395 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
1399 sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
1402 security_release_secctx(ctx, len);
1405 sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
1406 sig_data->pid = audit_sig_pid;
1407 if (audit_sig_sid) {
1408 memcpy(sig_data->ctx, ctx, len);
1409 security_release_secctx(ctx, len);
1411 audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
1412 sig_data, sizeof(*sig_data) + len);
1415 case AUDIT_TTY_GET: {
1416 struct audit_tty_status s;
1419 t = READ_ONCE(current->signal->audit_tty);
1420 s.enabled = t & AUDIT_TTY_ENABLE;
1421 s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1423 audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
1426 case AUDIT_TTY_SET: {
1427 struct audit_tty_status s, old;
1428 struct audit_buffer *ab;
1431 memset(&s, 0, sizeof(s));
1432 /* guard against past and future API changes */
1433 memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
1434 /* check if new data is valid */
1435 if ((s.enabled != 0 && s.enabled != 1) ||
1436 (s.log_passwd != 0 && s.log_passwd != 1))
1440 t = READ_ONCE(current->signal->audit_tty);
1442 t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD);
1443 t = xchg(¤t->signal->audit_tty, t);
1445 old.enabled = t & AUDIT_TTY_ENABLE;
1446 old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1448 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1449 audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
1450 " old-log_passwd=%d new-log_passwd=%d res=%d",
1451 old.enabled, s.enabled, old.log_passwd,
1452 s.log_passwd, !err);
1461 return err < 0 ? err : 0;
1465 * audit_receive - receive messages from a netlink control socket
1466 * @skb: the message buffer
1468 * Parse the provided skb and deal with any messages that may be present,
1469 * malformed skbs are discarded.
1471 static void audit_receive(struct sk_buff *skb)
1473 struct nlmsghdr *nlh;
1475 * len MUST be signed for nlmsg_next to be able to dec it below 0
1476 * if the nlmsg_len was not aligned
1481 nlh = nlmsg_hdr(skb);
1484 mutex_lock(&audit_cmd_mutex);
1485 while (nlmsg_ok(nlh, len)) {
1486 err = audit_receive_msg(skb, nlh);
1487 /* if err or if this message says it wants a response */
1488 if (err || (nlh->nlmsg_flags & NLM_F_ACK))
1489 netlink_ack(skb, nlh, err, NULL);
1491 nlh = nlmsg_next(nlh, &len);
1493 mutex_unlock(&audit_cmd_mutex);
1496 /* Run custom bind function on netlink socket group connect or bind requests. */
1497 static int audit_bind(struct net *net, int group)
1499 if (!capable(CAP_AUDIT_READ))
1505 static int __net_init audit_net_init(struct net *net)
1507 struct netlink_kernel_cfg cfg = {
1508 .input = audit_receive,
1510 .flags = NL_CFG_F_NONROOT_RECV,
1511 .groups = AUDIT_NLGRP_MAX,
1514 struct audit_net *aunet = net_generic(net, audit_net_id);
1516 aunet->sk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
1517 if (aunet->sk == NULL) {
1518 audit_panic("cannot initialize netlink socket in namespace");
1521 aunet->sk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
1526 static void __net_exit audit_net_exit(struct net *net)
1528 struct audit_net *aunet = net_generic(net, audit_net_id);
1530 /* NOTE: you would think that we would want to check the auditd
1531 * connection and potentially reset it here if it lives in this
1532 * namespace, but since the auditd connection tracking struct holds a
1533 * reference to this namespace (see auditd_set()) we are only ever
1534 * going to get here after that connection has been released */
1536 netlink_kernel_release(aunet->sk);
1539 static struct pernet_operations audit_net_ops __net_initdata = {
1540 .init = audit_net_init,
1541 .exit = audit_net_exit,
1542 .id = &audit_net_id,
1543 .size = sizeof(struct audit_net),
1546 /* Initialize audit support at boot time. */
1547 static int __init audit_init(void)
1551 if (audit_initialized == AUDIT_DISABLED)
1554 audit_buffer_cache = kmem_cache_create("audit_buffer",
1555 sizeof(struct audit_buffer),
1556 0, SLAB_PANIC, NULL);
1558 skb_queue_head_init(&audit_queue);
1559 skb_queue_head_init(&audit_retry_queue);
1560 skb_queue_head_init(&audit_hold_queue);
1562 for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
1563 INIT_LIST_HEAD(&audit_inode_hash[i]);
1565 pr_info("initializing netlink subsys (%s)\n",
1566 audit_default ? "enabled" : "disabled");
1567 register_pernet_subsys(&audit_net_ops);
1569 audit_initialized = AUDIT_INITIALIZED;
1571 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
1572 if (IS_ERR(kauditd_task)) {
1573 int err = PTR_ERR(kauditd_task);
1574 panic("audit: failed to start the kauditd thread (%d)\n", err);
1577 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL,
1578 "state=initialized audit_enabled=%u res=1",
1583 __initcall(audit_init);
1585 /* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
1586 static int __init audit_enable(char *str)
1588 audit_default = !!simple_strtol(str, NULL, 0);
1590 audit_initialized = AUDIT_DISABLED;
1591 audit_enabled = audit_default;
1592 audit_ever_enabled = !!audit_enabled;
1594 pr_info("%s\n", audit_default ?
1595 "enabled (after initialization)" : "disabled (until reboot)");
1599 __setup("audit=", audit_enable);
1601 /* Process kernel command-line parameter at boot time.
1602 * audit_backlog_limit=<n> */
1603 static int __init audit_backlog_limit_set(char *str)
1605 u32 audit_backlog_limit_arg;
1607 pr_info("audit_backlog_limit: ");
1608 if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
1609 pr_cont("using default of %u, unable to parse %s\n",
1610 audit_backlog_limit, str);
1614 audit_backlog_limit = audit_backlog_limit_arg;
1615 pr_cont("%d\n", audit_backlog_limit);
1619 __setup("audit_backlog_limit=", audit_backlog_limit_set);
1621 static void audit_buffer_free(struct audit_buffer *ab)
1627 kmem_cache_free(audit_buffer_cache, ab);
1630 static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx,
1631 gfp_t gfp_mask, int type)
1633 struct audit_buffer *ab;
1635 ab = kmem_cache_alloc(audit_buffer_cache, gfp_mask);
1639 ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
1642 if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0))
1646 ab->gfp_mask = gfp_mask;
1651 audit_buffer_free(ab);
1656 * audit_serial - compute a serial number for the audit record
1658 * Compute a serial number for the audit record. Audit records are
1659 * written to user-space as soon as they are generated, so a complete
1660 * audit record may be written in several pieces. The timestamp of the
1661 * record and this serial number are used by the user-space tools to
1662 * determine which pieces belong to the same audit record. The
1663 * (timestamp,serial) tuple is unique for each syscall and is live from
1664 * syscall entry to syscall exit.
1666 * NOTE: Another possibility is to store the formatted records off the
1667 * audit context (for those records that have a context), and emit them
1668 * all at syscall exit. However, this could delay the reporting of
1669 * significant errors until syscall exit (or never, if the system
1672 unsigned int audit_serial(void)
1674 static atomic_t serial = ATOMIC_INIT(0);
1676 return atomic_add_return(1, &serial);
1679 static inline void audit_get_stamp(struct audit_context *ctx,
1680 struct timespec64 *t, unsigned int *serial)
1682 if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
1683 *t = current_kernel_time64();
1684 *serial = audit_serial();
1689 * audit_log_start - obtain an audit buffer
1690 * @ctx: audit_context (may be NULL)
1691 * @gfp_mask: type of allocation
1692 * @type: audit message type
1694 * Returns audit_buffer pointer on success or NULL on error.
1696 * Obtain an audit buffer. This routine does locking to obtain the
1697 * audit buffer, but then no locking is required for calls to
1698 * audit_log_*format. If the task (ctx) is a task that is currently in a
1699 * syscall, then the syscall is marked as auditable and an audit record
1700 * will be written at syscall exit. If there is no associated task, then
1701 * task context (ctx) should be NULL.
1703 struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1706 struct audit_buffer *ab;
1707 struct timespec64 t;
1708 unsigned int uninitialized_var(serial);
1710 if (audit_initialized != AUDIT_INITIALIZED)
1713 if (unlikely(!audit_filter(type, AUDIT_FILTER_TYPE)))
1716 /* NOTE: don't ever fail/sleep on these two conditions:
1717 * 1. auditd generated record - since we need auditd to drain the
1718 * queue; also, when we are checking for auditd, compare PIDs using
1719 * task_tgid_vnr() since auditd_pid is set in audit_receive_msg()
1720 * using a PID anchored in the caller's namespace
1721 * 2. generator holding the audit_cmd_mutex - we don't want to block
1722 * while holding the mutex */
1723 if (!(auditd_test_task(current) ||
1724 (current == __mutex_owner(&audit_cmd_mutex)))) {
1725 long stime = audit_backlog_wait_time;
1727 while (audit_backlog_limit &&
1728 (skb_queue_len(&audit_queue) > audit_backlog_limit)) {
1729 /* wake kauditd to try and flush the queue */
1730 wake_up_interruptible(&kauditd_wait);
1732 /* sleep if we are allowed and we haven't exhausted our
1733 * backlog wait limit */
1734 if (gfpflags_allow_blocking(gfp_mask) && (stime > 0)) {
1735 DECLARE_WAITQUEUE(wait, current);
1737 add_wait_queue_exclusive(&audit_backlog_wait,
1739 set_current_state(TASK_UNINTERRUPTIBLE);
1740 stime = schedule_timeout(stime);
1741 remove_wait_queue(&audit_backlog_wait, &wait);
1743 if (audit_rate_check() && printk_ratelimit())
1744 pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
1745 skb_queue_len(&audit_queue),
1746 audit_backlog_limit);
1747 audit_log_lost("backlog limit exceeded");
1753 ab = audit_buffer_alloc(ctx, gfp_mask, type);
1755 audit_log_lost("out of memory in audit_log_start");
1759 audit_get_stamp(ab->ctx, &t, &serial);
1760 audit_log_format(ab, "audit(%llu.%03lu:%u): ",
1761 (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
1767 * audit_expand - expand skb in the audit buffer
1769 * @extra: space to add at tail of the skb
1771 * Returns 0 (no space) on failed expansion, or available space if
1774 static inline int audit_expand(struct audit_buffer *ab, int extra)
1776 struct sk_buff *skb = ab->skb;
1777 int oldtail = skb_tailroom(skb);
1778 int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1779 int newtail = skb_tailroom(skb);
1782 audit_log_lost("out of memory in audit_expand");
1786 skb->truesize += newtail - oldtail;
1791 * Format an audit message into the audit buffer. If there isn't enough
1792 * room in the audit buffer, more room will be allocated and vsnprint
1793 * will be called a second time. Currently, we assume that a printk
1794 * can't format message larger than 1024 bytes, so we don't either.
1796 static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1800 struct sk_buff *skb;
1808 avail = skb_tailroom(skb);
1810 avail = audit_expand(ab, AUDIT_BUFSIZ);
1814 va_copy(args2, args);
1815 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1817 /* The printk buffer is 1024 bytes long, so if we get
1818 * here and AUDIT_BUFSIZ is at least 1024, then we can
1819 * log everything that printk could have logged. */
1820 avail = audit_expand(ab,
1821 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1824 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1835 * audit_log_format - format a message into the audit buffer.
1837 * @fmt: format string
1838 * @...: optional parameters matching @fmt string
1840 * All the work is done in audit_log_vformat.
1842 void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1848 va_start(args, fmt);
1849 audit_log_vformat(ab, fmt, args);
1854 * audit_log_n_hex - convert a buffer to hex and append it to the audit skb
1855 * @ab: the audit_buffer
1856 * @buf: buffer to convert to hex
1857 * @len: length of @buf to be converted
1859 * No return value; failure to expand is silently ignored.
1861 * This function will take the passed buf and convert it into a string of
1862 * ascii hex digits. The new string is placed onto the skb.
1864 void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
1867 int i, avail, new_len;
1869 struct sk_buff *skb;
1876 avail = skb_tailroom(skb);
1878 if (new_len >= avail) {
1879 /* Round the buffer request up to the next multiple */
1880 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1881 avail = audit_expand(ab, new_len);
1886 ptr = skb_tail_pointer(skb);
1887 for (i = 0; i < len; i++)
1888 ptr = hex_byte_pack_upper(ptr, buf[i]);
1890 skb_put(skb, len << 1); /* new string is twice the old string */
1894 * Format a string of no more than slen characters into the audit buffer,
1895 * enclosed in quote marks.
1897 void audit_log_n_string(struct audit_buffer *ab, const char *string,
1902 struct sk_buff *skb;
1909 avail = skb_tailroom(skb);
1910 new_len = slen + 3; /* enclosing quotes + null terminator */
1911 if (new_len > avail) {
1912 avail = audit_expand(ab, new_len);
1916 ptr = skb_tail_pointer(skb);
1918 memcpy(ptr, string, slen);
1922 skb_put(skb, slen + 2); /* don't include null terminator */
1926 * audit_string_contains_control - does a string need to be logged in hex
1927 * @string: string to be checked
1928 * @len: max length of the string to check
1930 bool audit_string_contains_control(const char *string, size_t len)
1932 const unsigned char *p;
1933 for (p = string; p < (const unsigned char *)string + len; p++) {
1934 if (*p == '"' || *p < 0x21 || *p > 0x7e)
1941 * audit_log_n_untrustedstring - log a string that may contain random characters
1943 * @len: length of string (not including trailing null)
1944 * @string: string to be logged
1946 * This code will escape a string that is passed to it if the string
1947 * contains a control character, unprintable character, double quote mark,
1948 * or a space. Unescaped strings will start and end with a double quote mark.
1949 * Strings that are escaped are printed in hex (2 digits per char).
1951 * The caller specifies the number of characters in the string to log, which may
1952 * or may not be the entire string.
1954 void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
1957 if (audit_string_contains_control(string, len))
1958 audit_log_n_hex(ab, string, len);
1960 audit_log_n_string(ab, string, len);
1964 * audit_log_untrustedstring - log a string that may contain random characters
1966 * @string: string to be logged
1968 * Same as audit_log_n_untrustedstring(), except that strlen is used to
1969 * determine string length.
1971 void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
1973 audit_log_n_untrustedstring(ab, string, strlen(string));
1976 /* This is a helper-function to print the escaped d_path */
1977 void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
1978 const struct path *path)
1983 audit_log_format(ab, "%s", prefix);
1985 /* We will allow 11 spaces for ' (deleted)' to be appended */
1986 pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
1988 audit_log_string(ab, "<no_memory>");
1991 p = d_path(path, pathname, PATH_MAX+11);
1992 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
1993 /* FIXME: can we save some information here? */
1994 audit_log_string(ab, "<too_long>");
1996 audit_log_untrustedstring(ab, p);
2000 void audit_log_session_info(struct audit_buffer *ab)
2002 unsigned int sessionid = audit_get_sessionid(current);
2003 uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
2005 audit_log_format(ab, " auid=%u ses=%u", auid, sessionid);
2008 void audit_log_key(struct audit_buffer *ab, char *key)
2010 audit_log_format(ab, " key=");
2012 audit_log_untrustedstring(ab, key);
2014 audit_log_format(ab, "(null)");
2017 void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap)
2021 audit_log_format(ab, " %s=", prefix);
2022 CAP_FOR_EACH_U32(i) {
2023 audit_log_format(ab, "%08x",
2024 cap->cap[CAP_LAST_U32 - i]);
2028 static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
2030 audit_log_cap(ab, "cap_fp", &name->fcap.permitted);
2031 audit_log_cap(ab, "cap_fi", &name->fcap.inheritable);
2032 audit_log_format(ab, " cap_fe=%d cap_fver=%x",
2033 name->fcap.fE, name->fcap_ver);
2036 static inline int audit_copy_fcaps(struct audit_names *name,
2037 const struct dentry *dentry)
2039 struct cpu_vfs_cap_data caps;
2045 rc = get_vfs_caps_from_disk(dentry, &caps);
2049 name->fcap.permitted = caps.permitted;
2050 name->fcap.inheritable = caps.inheritable;
2051 name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
2052 name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >>
2053 VFS_CAP_REVISION_SHIFT;
2058 /* Copy inode data into an audit_names. */
2059 void audit_copy_inode(struct audit_names *name, const struct dentry *dentry,
2060 struct inode *inode)
2062 name->ino = inode->i_ino;
2063 name->dev = inode->i_sb->s_dev;
2064 name->mode = inode->i_mode;
2065 name->uid = inode->i_uid;
2066 name->gid = inode->i_gid;
2067 name->rdev = inode->i_rdev;
2068 security_inode_getsecid(inode, &name->osid);
2069 audit_copy_fcaps(name, dentry);
2073 * audit_log_name - produce AUDIT_PATH record from struct audit_names
2074 * @context: audit_context for the task
2075 * @n: audit_names structure with reportable details
2076 * @path: optional path to report instead of audit_names->name
2077 * @record_num: record number to report when handling a list of names
2078 * @call_panic: optional pointer to int that will be updated if secid fails
2080 void audit_log_name(struct audit_context *context, struct audit_names *n,
2081 const struct path *path, int record_num, int *call_panic)
2083 struct audit_buffer *ab;
2084 ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH);
2088 audit_log_format(ab, "item=%d", record_num);
2091 audit_log_d_path(ab, " name=", path);
2093 switch (n->name_len) {
2094 case AUDIT_NAME_FULL:
2095 /* log the full path */
2096 audit_log_format(ab, " name=");
2097 audit_log_untrustedstring(ab, n->name->name);
2100 /* name was specified as a relative path and the
2101 * directory component is the cwd */
2102 audit_log_d_path(ab, " name=", &context->pwd);
2105 /* log the name's directory component */
2106 audit_log_format(ab, " name=");
2107 audit_log_n_untrustedstring(ab, n->name->name,
2111 audit_log_format(ab, " name=(null)");
2113 if (n->ino != AUDIT_INO_UNSET)
2114 audit_log_format(ab, " inode=%lu"
2115 " dev=%02x:%02x mode=%#ho"
2116 " ouid=%u ogid=%u rdev=%02x:%02x",
2121 from_kuid(&init_user_ns, n->uid),
2122 from_kgid(&init_user_ns, n->gid),
2128 if (security_secid_to_secctx(
2129 n->osid, &ctx, &len)) {
2130 audit_log_format(ab, " osid=%u", n->osid);
2134 audit_log_format(ab, " obj=%s", ctx);
2135 security_release_secctx(ctx, len);
2139 /* log the audit_names record type */
2140 audit_log_format(ab, " nametype=");
2142 case AUDIT_TYPE_NORMAL:
2143 audit_log_format(ab, "NORMAL");
2145 case AUDIT_TYPE_PARENT:
2146 audit_log_format(ab, "PARENT");
2148 case AUDIT_TYPE_CHILD_DELETE:
2149 audit_log_format(ab, "DELETE");
2151 case AUDIT_TYPE_CHILD_CREATE:
2152 audit_log_format(ab, "CREATE");
2155 audit_log_format(ab, "UNKNOWN");
2159 audit_log_fcaps(ab, n);
2163 int audit_log_task_context(struct audit_buffer *ab)
2170 security_task_getsecid(current, &sid);
2174 error = security_secid_to_secctx(sid, &ctx, &len);
2176 if (error != -EINVAL)
2181 audit_log_format(ab, " subj=%s", ctx);
2182 security_release_secctx(ctx, len);
2186 audit_panic("error in audit_log_task_context");
2189 EXPORT_SYMBOL(audit_log_task_context);
2191 void audit_log_d_path_exe(struct audit_buffer *ab,
2192 struct mm_struct *mm)
2194 struct file *exe_file;
2199 exe_file = get_mm_exe_file(mm);
2203 audit_log_d_path(ab, " exe=", &exe_file->f_path);
2207 audit_log_format(ab, " exe=(null)");
2210 struct tty_struct *audit_get_tty(struct task_struct *tsk)
2212 struct tty_struct *tty = NULL;
2213 unsigned long flags;
2215 spin_lock_irqsave(&tsk->sighand->siglock, flags);
2217 tty = tty_kref_get(tsk->signal->tty);
2218 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
2222 void audit_put_tty(struct tty_struct *tty)
2227 void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
2229 const struct cred *cred;
2230 char comm[sizeof(tsk->comm)];
2231 struct tty_struct *tty;
2236 /* tsk == current */
2237 cred = current_cred();
2238 tty = audit_get_tty(tsk);
2239 audit_log_format(ab,
2240 " ppid=%d pid=%d auid=%u uid=%u gid=%u"
2241 " euid=%u suid=%u fsuid=%u"
2242 " egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
2245 from_kuid(&init_user_ns, audit_get_loginuid(tsk)),
2246 from_kuid(&init_user_ns, cred->uid),
2247 from_kgid(&init_user_ns, cred->gid),
2248 from_kuid(&init_user_ns, cred->euid),
2249 from_kuid(&init_user_ns, cred->suid),
2250 from_kuid(&init_user_ns, cred->fsuid),
2251 from_kgid(&init_user_ns, cred->egid),
2252 from_kgid(&init_user_ns, cred->sgid),
2253 from_kgid(&init_user_ns, cred->fsgid),
2254 tty ? tty_name(tty) : "(none)",
2255 audit_get_sessionid(tsk));
2257 audit_log_format(ab, " comm=");
2258 audit_log_untrustedstring(ab, get_task_comm(comm, tsk));
2259 audit_log_d_path_exe(ab, tsk->mm);
2260 audit_log_task_context(ab);
2262 EXPORT_SYMBOL(audit_log_task_info);
2265 * audit_log_link_denied - report a link restriction denial
2266 * @operation: specific link operation
2267 * @link: the path that triggered the restriction
2269 void audit_log_link_denied(const char *operation, const struct path *link)
2271 struct audit_buffer *ab;
2272 struct audit_names *name;
2274 name = kzalloc(sizeof(*name), GFP_NOFS);
2278 /* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */
2279 ab = audit_log_start(current->audit_context, GFP_KERNEL,
2283 audit_log_format(ab, "op=%s", operation);
2284 audit_log_task_info(ab, current);
2285 audit_log_format(ab, " res=0");
2288 /* Generate AUDIT_PATH record with object. */
2289 name->type = AUDIT_TYPE_NORMAL;
2290 audit_copy_inode(name, link->dentry, d_backing_inode(link->dentry));
2291 audit_log_name(current->audit_context, name, link, 0, NULL);
2297 * audit_log_end - end one audit record
2298 * @ab: the audit_buffer
2300 * We can not do a netlink send inside an irq context because it blocks (last
2301 * arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a
2302 * queue and a tasklet is scheduled to remove them from the queue outside the
2303 * irq context. May be called in any context.
2305 void audit_log_end(struct audit_buffer *ab)
2307 struct sk_buff *skb;
2308 struct nlmsghdr *nlh;
2313 if (audit_rate_check()) {
2317 /* setup the netlink header, see the comments in
2318 * kauditd_send_multicast_skb() for length quirks */
2319 nlh = nlmsg_hdr(skb);
2320 nlh->nlmsg_len = skb->len - NLMSG_HDRLEN;
2322 /* queue the netlink packet and poke the kauditd thread */
2323 skb_queue_tail(&audit_queue, skb);
2324 wake_up_interruptible(&kauditd_wait);
2326 audit_log_lost("rate limit exceeded");
2328 audit_buffer_free(ab);
2332 * audit_log - Log an audit record
2333 * @ctx: audit context
2334 * @gfp_mask: type of allocation
2335 * @type: audit message type
2336 * @fmt: format string to use
2337 * @...: variable parameters matching the format string
2339 * This is a convenience function that calls audit_log_start,
2340 * audit_log_vformat, and audit_log_end. It may be called
2343 void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
2344 const char *fmt, ...)
2346 struct audit_buffer *ab;
2349 ab = audit_log_start(ctx, gfp_mask, type);
2351 va_start(args, fmt);
2352 audit_log_vformat(ab, fmt, args);
2358 #ifdef CONFIG_SECURITY
2360 * audit_log_secctx - Converts and logs SELinux context
2362 * @secid: security number
2364 * This is a helper function that calls security_secid_to_secctx to convert
2365 * secid to secctx and then adds the (converted) SELinux context to the audit
2366 * log by calling audit_log_format, thus also preventing leak of internal secid
2367 * to userspace. If secid cannot be converted audit_panic is called.
2369 void audit_log_secctx(struct audit_buffer *ab, u32 secid)
2374 if (security_secid_to_secctx(secid, &secctx, &len)) {
2375 audit_panic("Cannot convert secid to context");
2377 audit_log_format(ab, " obj=%s", secctx);
2378 security_release_secctx(secctx, len);
2381 EXPORT_SYMBOL(audit_log_secctx);
2384 EXPORT_SYMBOL(audit_log_start);
2385 EXPORT_SYMBOL(audit_log_end);
2386 EXPORT_SYMBOL(audit_log_format);
2387 EXPORT_SYMBOL(audit_log);