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
512 * @error: error code (unused)
515 * This should only be used by the kauditd_thread when it fails to flush the
518 static void kauditd_rehold_skb(struct sk_buff *skb, __always_unused int error)
520 /* put the record back in the queue */
521 skb_queue_tail(&audit_hold_queue, skb);
525 * kauditd_hold_skb - Queue an audit record, waiting for auditd
530 * Queue the audit record, waiting for an instance of auditd. When this
531 * function is called we haven't given up yet on sending the record, but things
532 * are not looking good. The first thing we want to do is try to write the
533 * record via printk and then see if we want to try and hold on to the record
534 * and queue it, if we have room. If we want to hold on to the record, but we
535 * don't have room, record a record lost message.
537 static void kauditd_hold_skb(struct sk_buff *skb, int error)
539 /* at this point it is uncertain if we will ever send this to auditd so
540 * try to send the message via printk before we go any further */
541 kauditd_printk_skb(skb);
543 /* can we just silently drop the message? */
547 /* the hold queue is only for when the daemon goes away completely,
548 * not -EAGAIN failures; if we are in a -EAGAIN state requeue the
549 * record on the retry queue unless it's full, in which case drop it
551 if (error == -EAGAIN) {
552 if (!audit_backlog_limit ||
553 skb_queue_len(&audit_retry_queue) < audit_backlog_limit) {
554 skb_queue_tail(&audit_retry_queue, skb);
557 audit_log_lost("kauditd retry queue overflow");
561 /* if we have room in the hold queue, queue the message */
562 if (!audit_backlog_limit ||
563 skb_queue_len(&audit_hold_queue) < audit_backlog_limit) {
564 skb_queue_tail(&audit_hold_queue, skb);
568 /* we have no other options - drop the message */
569 audit_log_lost("kauditd hold queue overflow");
575 * kauditd_retry_skb - Queue an audit record, attempt to send again to auditd
577 * @error: error code (unused)
580 * Not as serious as kauditd_hold_skb() as we still have a connected auditd,
581 * but for some reason we are having problems sending it audit records so
582 * queue the given record and attempt to resend.
584 static void kauditd_retry_skb(struct sk_buff *skb, __always_unused int error)
586 if (!audit_backlog_limit ||
587 skb_queue_len(&audit_retry_queue) < audit_backlog_limit) {
588 skb_queue_tail(&audit_retry_queue, skb);
592 /* we have to drop the record, send it via printk as a last effort */
593 kauditd_printk_skb(skb);
594 audit_log_lost("kauditd retry queue overflow");
599 * auditd_reset - Disconnect the auditd connection
600 * @ac: auditd connection state
603 * Break the auditd/kauditd connection and move all the queued records into the
604 * hold queue in case auditd reconnects. It is important to note that the @ac
605 * pointer should never be dereferenced inside this function as it may be NULL
606 * or invalid, you can only compare the memory address! If @ac is NULL then
607 * the connection will always be reset.
609 static void auditd_reset(const struct auditd_connection *ac)
613 struct auditd_connection *ac_old;
615 /* if it isn't already broken, break the connection */
616 spin_lock_irqsave(&auditd_conn_lock, flags);
617 ac_old = rcu_dereference_protected(auditd_conn,
618 lockdep_is_held(&auditd_conn_lock));
619 if (ac && ac != ac_old) {
620 /* someone already registered a new auditd connection */
621 spin_unlock_irqrestore(&auditd_conn_lock, flags);
624 rcu_assign_pointer(auditd_conn, NULL);
625 spin_unlock_irqrestore(&auditd_conn_lock, flags);
628 call_rcu(&ac_old->rcu, auditd_conn_free);
630 /* flush the retry queue to the hold queue, but don't touch the main
631 * queue since we need to process that normally for multicast */
632 while ((skb = skb_dequeue(&audit_retry_queue)))
633 kauditd_hold_skb(skb, -ECONNREFUSED);
637 * auditd_send_unicast_skb - Send a record via unicast to auditd
641 * Send a skb to the audit daemon, returns positive/zero values on success and
642 * negative values on failure; in all cases the skb will be consumed by this
643 * function. If the send results in -ECONNREFUSED the connection with auditd
644 * will be reset. This function may sleep so callers should not hold any locks
645 * where this would cause a problem.
647 static int auditd_send_unicast_skb(struct sk_buff *skb)
653 struct auditd_connection *ac;
655 /* NOTE: we can't call netlink_unicast while in the RCU section so
656 * take a reference to the network namespace and grab local
657 * copies of the namespace, the sock, and the portid; the
658 * namespace and sock aren't going to go away while we hold a
659 * reference and if the portid does become invalid after the RCU
660 * section netlink_unicast() should safely return an error */
663 ac = rcu_dereference(auditd_conn);
670 net = get_net(ac->net);
671 sk = audit_get_sk(net);
675 rc = netlink_unicast(sk, skb, portid, 0);
683 if (ac && rc == -ECONNREFUSED)
689 * kauditd_send_queue - Helper for kauditd_thread to flush skb queues
690 * @sk: the sending sock
691 * @portid: the netlink destination
692 * @queue: the skb queue to process
693 * @retry_limit: limit on number of netlink unicast failures
694 * @skb_hook: per-skb hook for additional processing
695 * @err_hook: hook called if the skb fails the netlink unicast send
698 * Run through the given queue and attempt to send the audit records to auditd,
699 * returns zero on success, negative values on failure. It is up to the caller
700 * to ensure that the @sk is valid for the duration of this function.
703 static int kauditd_send_queue(struct sock *sk, u32 portid,
704 struct sk_buff_head *queue,
705 unsigned int retry_limit,
706 void (*skb_hook)(struct sk_buff *skb),
707 void (*err_hook)(struct sk_buff *skb, int error))
710 struct sk_buff *skb = NULL;
711 struct sk_buff *skb_tail;
712 unsigned int failed = 0;
714 /* NOTE: kauditd_thread takes care of all our locking, we just use
715 * the netlink info passed to us (e.g. sk and portid) */
717 skb_tail = skb_peek_tail(queue);
718 while ((skb != skb_tail) && (skb = skb_dequeue(queue))) {
719 /* call the skb_hook for each skb we touch */
723 /* can we send to anyone via unicast? */
726 (*err_hook)(skb, -ECONNREFUSED);
731 /* grab an extra skb reference in case of error */
733 rc = netlink_unicast(sk, skb, portid, 0);
735 /* send failed - try a few times unless fatal error */
736 if (++failed >= retry_limit ||
737 rc == -ECONNREFUSED || rc == -EPERM) {
740 (*err_hook)(skb, rc);
743 /* continue to drain the queue */
748 /* skb sent - drop the extra reference and continue */
754 return (rc >= 0 ? 0 : rc);
758 * kauditd_send_multicast_skb - Send a record to any multicast listeners
762 * Write a multicast message to anyone listening in the initial network
763 * namespace. This function doesn't consume an skb as might be expected since
764 * it has to copy it anyways.
766 static void kauditd_send_multicast_skb(struct sk_buff *skb)
768 struct sk_buff *copy;
769 struct sock *sock = audit_get_sk(&init_net);
770 struct nlmsghdr *nlh;
772 /* NOTE: we are not taking an additional reference for init_net since
773 * we don't have to worry about it going away */
775 if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
779 * The seemingly wasteful skb_copy() rather than bumping the refcount
780 * using skb_get() is necessary because non-standard mods are made to
781 * the skb by the original kaudit unicast socket send routine. The
782 * existing auditd daemon assumes this breakage. Fixing this would
783 * require co-ordinating a change in the established protocol between
784 * the kaudit kernel subsystem and the auditd userspace code. There is
785 * no reason for new multicast clients to continue with this
788 copy = skb_copy(skb, GFP_KERNEL);
791 nlh = nlmsg_hdr(copy);
792 nlh->nlmsg_len = skb->len;
794 nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL);
798 * kauditd_thread - Worker thread to send audit records to userspace
801 static int kauditd_thread(void *dummy)
805 struct net *net = NULL;
806 struct sock *sk = NULL;
807 struct auditd_connection *ac;
809 #define UNICAST_RETRIES 5
812 while (!kthread_should_stop()) {
813 /* NOTE: see the lock comments in auditd_send_unicast_skb() */
815 ac = rcu_dereference(auditd_conn);
820 net = get_net(ac->net);
821 sk = audit_get_sk(net);
825 /* attempt to flush the hold queue */
826 rc = kauditd_send_queue(sk, portid,
827 &audit_hold_queue, UNICAST_RETRIES,
828 NULL, kauditd_rehold_skb);
835 /* attempt to flush the retry queue */
836 rc = kauditd_send_queue(sk, portid,
837 &audit_retry_queue, UNICAST_RETRIES,
838 NULL, kauditd_hold_skb);
846 /* process the main queue - do the multicast send and attempt
847 * unicast, dump failed record sends to the retry queue; if
848 * sk == NULL due to previous failures we will just do the
849 * multicast send and move the record to the hold queue */
850 rc = kauditd_send_queue(sk, portid, &audit_queue, 1,
851 kauditd_send_multicast_skb,
853 kauditd_retry_skb : kauditd_hold_skb));
858 /* drop our netns reference, no auditd sends past this line */
864 /* we have processed all the queues so wake everyone */
865 wake_up(&audit_backlog_wait);
867 /* NOTE: we want to wake up if there is anything on the queue,
868 * regardless of if an auditd is connected, as we need to
869 * do the multicast send and rotate records from the
870 * main queue to the retry/hold queues */
871 wait_event_freezable(kauditd_wait,
872 (skb_queue_len(&audit_queue) ? 1 : 0));
878 int audit_send_list_thread(void *_dest)
880 struct audit_netlink_list *dest = _dest;
882 struct sock *sk = audit_get_sk(dest->net);
884 /* wait for parent to finish and send an ACK */
885 mutex_lock(&audit_cmd_mutex);
886 mutex_unlock(&audit_cmd_mutex);
888 while ((skb = __skb_dequeue(&dest->q)) != NULL)
889 netlink_unicast(sk, skb, dest->portid, 0);
897 struct sk_buff *audit_make_reply(int seq, int type, int done,
898 int multi, const void *payload, int size)
901 struct nlmsghdr *nlh;
903 int flags = multi ? NLM_F_MULTI : 0;
904 int t = done ? NLMSG_DONE : type;
906 skb = nlmsg_new(size, GFP_KERNEL);
910 nlh = nlmsg_put(skb, 0, seq, t, size, flags);
913 data = nlmsg_data(nlh);
914 memcpy(data, payload, size);
922 static void audit_free_reply(struct audit_reply *reply)
928 kfree_skb(reply->skb);
934 static int audit_send_reply_thread(void *arg)
936 struct audit_reply *reply = (struct audit_reply *)arg;
938 mutex_lock(&audit_cmd_mutex);
939 mutex_unlock(&audit_cmd_mutex);
941 /* Ignore failure. It'll only happen if the sender goes away,
942 because our timeout is set to infinite. */
943 netlink_unicast(audit_get_sk(reply->net), reply->skb, reply->portid, 0);
945 audit_free_reply(reply);
950 * audit_send_reply - send an audit reply message via netlink
951 * @request_skb: skb of request we are replying to (used to target the reply)
952 * @seq: sequence number
953 * @type: audit message type
954 * @done: done (last) flag
955 * @multi: multi-part message flag
956 * @payload: payload data
957 * @size: payload size
959 * Allocates a skb, builds the netlink message, and sends it to the port id.
961 static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
962 int multi, const void *payload, int size)
964 struct task_struct *tsk;
965 struct audit_reply *reply;
967 reply = kzalloc(sizeof(*reply), GFP_KERNEL);
971 reply->skb = audit_make_reply(seq, type, done, multi, payload, size);
974 reply->net = get_net(sock_net(NETLINK_CB(request_skb).sk));
975 reply->portid = NETLINK_CB(request_skb).portid;
977 tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
984 audit_free_reply(reply);
988 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
991 static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
995 /* Only support initial user namespace for now. */
997 * We return ECONNREFUSED because it tricks userspace into thinking
998 * that audit was not configured into the kernel. Lots of users
999 * configure their PAM stack (because that's what the distro does)
1000 * to reject login if unable to send messages to audit. If we return
1001 * ECONNREFUSED the PAM stack thinks the kernel does not have audit
1002 * configured in and will let login proceed. If we return EPERM
1003 * userspace will reject all logins. This should be removed when we
1004 * support non init namespaces!!
1006 if (current_user_ns() != &init_user_ns)
1007 return -ECONNREFUSED;
1016 case AUDIT_GET_FEATURE:
1017 case AUDIT_SET_FEATURE:
1018 case AUDIT_LIST_RULES:
1019 case AUDIT_ADD_RULE:
1020 case AUDIT_DEL_RULE:
1021 case AUDIT_SIGNAL_INFO:
1025 case AUDIT_MAKE_EQUIV:
1026 /* Only support auditd and auditctl in initial pid namespace
1028 if (task_active_pid_ns(current) != &init_pid_ns)
1031 if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
1035 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1036 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1037 if (!netlink_capable(skb, CAP_AUDIT_WRITE))
1040 default: /* bad msg */
1047 static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
1049 uid_t uid = from_kuid(&init_user_ns, current_uid());
1050 pid_t pid = task_tgid_nr(current);
1052 if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
1057 *ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
1060 audit_log_format(*ab, "pid=%d uid=%u", pid, uid);
1061 audit_log_session_info(*ab);
1062 audit_log_task_context(*ab);
1065 int is_audit_feature_set(int i)
1067 return af.features & AUDIT_FEATURE_TO_MASK(i);
1071 static int audit_get_feature(struct sk_buff *skb)
1075 seq = nlmsg_hdr(skb)->nlmsg_seq;
1077 audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af));
1082 static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
1083 u32 old_lock, u32 new_lock, int res)
1085 struct audit_buffer *ab;
1087 if (audit_enabled == AUDIT_OFF)
1090 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_FEATURE_CHANGE);
1093 audit_log_task_info(ab, current);
1094 audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
1095 audit_feature_names[which], !!old_feature, !!new_feature,
1096 !!old_lock, !!new_lock, res);
1100 static int audit_set_feature(struct audit_features *uaf)
1104 BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
1106 /* if there is ever a version 2 we should handle that here */
1108 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1109 u32 feature = AUDIT_FEATURE_TO_MASK(i);
1110 u32 old_feature, new_feature, old_lock, new_lock;
1112 /* if we are not changing this feature, move along */
1113 if (!(feature & uaf->mask))
1116 old_feature = af.features & feature;
1117 new_feature = uaf->features & feature;
1118 new_lock = (uaf->lock | af.lock) & feature;
1119 old_lock = af.lock & feature;
1121 /* are we changing a locked feature? */
1122 if (old_lock && (new_feature != old_feature)) {
1123 audit_log_feature_change(i, old_feature, new_feature,
1124 old_lock, new_lock, 0);
1128 /* nothing invalid, do the changes */
1129 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1130 u32 feature = AUDIT_FEATURE_TO_MASK(i);
1131 u32 old_feature, new_feature, old_lock, new_lock;
1133 /* if we are not changing this feature, move along */
1134 if (!(feature & uaf->mask))
1137 old_feature = af.features & feature;
1138 new_feature = uaf->features & feature;
1139 old_lock = af.lock & feature;
1140 new_lock = (uaf->lock | af.lock) & feature;
1142 if (new_feature != old_feature)
1143 audit_log_feature_change(i, old_feature, new_feature,
1144 old_lock, new_lock, 1);
1147 af.features |= feature;
1149 af.features &= ~feature;
1150 af.lock |= new_lock;
1156 static int audit_replace(struct pid *pid)
1159 struct sk_buff *skb;
1161 pvnr = pid_vnr(pid);
1162 skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pvnr, sizeof(pvnr));
1165 return auditd_send_unicast_skb(skb);
1168 static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
1174 struct audit_buffer *ab;
1175 u16 msg_type = nlh->nlmsg_type;
1176 struct audit_sig_info *sig_data;
1180 err = audit_netlink_ok(skb, msg_type);
1184 seq = nlh->nlmsg_seq;
1185 data = nlmsg_data(nlh);
1186 data_len = nlmsg_len(nlh);
1190 struct audit_status s;
1191 memset(&s, 0, sizeof(s));
1192 s.enabled = audit_enabled;
1193 s.failure = audit_failure;
1194 /* NOTE: use pid_vnr() so the PID is relative to the current
1196 s.pid = auditd_pid_vnr();
1197 s.rate_limit = audit_rate_limit;
1198 s.backlog_limit = audit_backlog_limit;
1199 s.lost = atomic_read(&audit_lost);
1200 s.backlog = skb_queue_len(&audit_queue);
1201 s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL;
1202 s.backlog_wait_time = audit_backlog_wait_time;
1203 audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
1207 struct audit_status s;
1208 memset(&s, 0, sizeof(s));
1209 /* guard against past and future API changes */
1210 memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
1211 if (s.mask & AUDIT_STATUS_ENABLED) {
1212 err = audit_set_enabled(s.enabled);
1216 if (s.mask & AUDIT_STATUS_FAILURE) {
1217 err = audit_set_failure(s.failure);
1221 if (s.mask & AUDIT_STATUS_PID) {
1222 /* NOTE: we are using the vnr PID functions below
1223 * because the s.pid value is relative to the
1224 * namespace of the caller; at present this
1225 * doesn't matter much since you can really only
1226 * run auditd from the initial pid namespace, but
1227 * something to keep in mind if this changes */
1228 pid_t new_pid = s.pid;
1230 struct pid *req_pid = task_tgid(current);
1232 /* Sanity check - PID values must match. Setting
1233 * pid to 0 is how auditd ends auditing. */
1234 if (new_pid && (new_pid != pid_vnr(req_pid)))
1237 /* test the auditd connection */
1238 audit_replace(req_pid);
1240 auditd_pid = auditd_pid_vnr();
1242 /* replacing a healthy auditd is not allowed */
1244 audit_log_config_change("audit_pid",
1245 new_pid, auditd_pid, 0);
1248 /* only current auditd can unregister itself */
1249 if (pid_vnr(req_pid) != auditd_pid) {
1250 audit_log_config_change("audit_pid",
1251 new_pid, auditd_pid, 0);
1257 /* register a new auditd connection */
1258 err = auditd_set(req_pid,
1259 NETLINK_CB(skb).portid,
1260 sock_net(NETLINK_CB(skb).sk));
1261 if (audit_enabled != AUDIT_OFF)
1262 audit_log_config_change("audit_pid",
1269 /* try to process any backlog */
1270 wake_up_interruptible(&kauditd_wait);
1272 if (audit_enabled != AUDIT_OFF)
1273 audit_log_config_change("audit_pid",
1277 /* unregister the auditd connection */
1281 if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
1282 err = audit_set_rate_limit(s.rate_limit);
1286 if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
1287 err = audit_set_backlog_limit(s.backlog_limit);
1291 if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
1292 if (sizeof(s) > (size_t)nlh->nlmsg_len)
1294 if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
1296 err = audit_set_backlog_wait_time(s.backlog_wait_time);
1300 if (s.mask == AUDIT_STATUS_LOST) {
1301 u32 lost = atomic_xchg(&audit_lost, 0);
1303 audit_log_config_change("lost", 0, lost, 1);
1308 case AUDIT_GET_FEATURE:
1309 err = audit_get_feature(skb);
1313 case AUDIT_SET_FEATURE:
1314 if (data_len < sizeof(struct audit_features))
1316 err = audit_set_feature(data);
1321 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1322 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1323 if (!audit_enabled && msg_type != AUDIT_USER_AVC)
1325 /* exit early if there isn't at least one character to print */
1329 err = audit_filter(msg_type, AUDIT_FILTER_USER);
1330 if (err == 1) { /* match or error */
1334 if (msg_type == AUDIT_USER_TTY) {
1335 err = tty_audit_push();
1339 audit_log_common_recv_msg(&ab, msg_type);
1340 if (msg_type != AUDIT_USER_TTY) {
1341 /* ensure NULL termination */
1342 str[data_len - 1] = '\0';
1343 audit_log_format(ab, " msg='%.*s'",
1344 AUDIT_MESSAGE_TEXT_MAX,
1347 audit_log_format(ab, " data=");
1348 if (data_len > 0 && str[data_len - 1] == '\0')
1350 audit_log_n_untrustedstring(ab, str, data_len);
1355 case AUDIT_ADD_RULE:
1356 case AUDIT_DEL_RULE:
1357 if (data_len < sizeof(struct audit_rule_data))
1359 if (audit_enabled == AUDIT_LOCKED) {
1360 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1361 audit_log_format(ab, " audit_enabled=%d res=0", audit_enabled);
1365 err = audit_rule_change(msg_type, seq, data, data_len);
1367 case AUDIT_LIST_RULES:
1368 err = audit_list_rules_send(skb, seq);
1372 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1373 audit_log_format(ab, " op=trim res=1");
1376 case AUDIT_MAKE_EQUIV: {
1379 size_t msglen = data_len;
1383 if (msglen < 2 * sizeof(u32))
1385 memcpy(sizes, bufp, 2 * sizeof(u32));
1386 bufp += 2 * sizeof(u32);
1387 msglen -= 2 * sizeof(u32);
1388 old = audit_unpack_string(&bufp, &msglen, sizes[0]);
1393 new = audit_unpack_string(&bufp, &msglen, sizes[1]);
1399 /* OK, here comes... */
1400 err = audit_tag_tree(old, new);
1402 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1404 audit_log_format(ab, " op=make_equiv old=");
1405 audit_log_untrustedstring(ab, old);
1406 audit_log_format(ab, " new=");
1407 audit_log_untrustedstring(ab, new);
1408 audit_log_format(ab, " res=%d", !err);
1414 case AUDIT_SIGNAL_INFO:
1416 if (audit_sig_sid) {
1417 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
1421 sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
1424 security_release_secctx(ctx, len);
1427 sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
1428 sig_data->pid = audit_sig_pid;
1429 if (audit_sig_sid) {
1430 memcpy(sig_data->ctx, ctx, len);
1431 security_release_secctx(ctx, len);
1433 audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
1434 sig_data, sizeof(*sig_data) + len);
1437 case AUDIT_TTY_GET: {
1438 struct audit_tty_status s;
1441 t = READ_ONCE(current->signal->audit_tty);
1442 s.enabled = t & AUDIT_TTY_ENABLE;
1443 s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1445 audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
1448 case AUDIT_TTY_SET: {
1449 struct audit_tty_status s, old;
1450 struct audit_buffer *ab;
1453 memset(&s, 0, sizeof(s));
1454 /* guard against past and future API changes */
1455 memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
1456 /* check if new data is valid */
1457 if ((s.enabled != 0 && s.enabled != 1) ||
1458 (s.log_passwd != 0 && s.log_passwd != 1))
1462 t = READ_ONCE(current->signal->audit_tty);
1464 t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD);
1465 t = xchg(¤t->signal->audit_tty, t);
1467 old.enabled = t & AUDIT_TTY_ENABLE;
1468 old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1470 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1471 audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
1472 " old-log_passwd=%d new-log_passwd=%d res=%d",
1473 old.enabled, s.enabled, old.log_passwd,
1474 s.log_passwd, !err);
1483 return err < 0 ? err : 0;
1487 * audit_receive - receive messages from a netlink control socket
1488 * @skb: the message buffer
1490 * Parse the provided skb and deal with any messages that may be present,
1491 * malformed skbs are discarded.
1493 static void audit_receive(struct sk_buff *skb)
1495 struct nlmsghdr *nlh;
1497 * len MUST be signed for nlmsg_next to be able to dec it below 0
1498 * if the nlmsg_len was not aligned
1503 nlh = nlmsg_hdr(skb);
1506 mutex_lock(&audit_cmd_mutex);
1507 while (nlmsg_ok(nlh, len)) {
1508 err = audit_receive_msg(skb, nlh);
1509 /* if err or if this message says it wants a response */
1510 if (err || (nlh->nlmsg_flags & NLM_F_ACK))
1511 netlink_ack(skb, nlh, err, NULL);
1513 nlh = nlmsg_next(nlh, &len);
1515 mutex_unlock(&audit_cmd_mutex);
1518 /* Run custom bind function on netlink socket group connect or bind requests. */
1519 static int audit_bind(struct net *net, int group)
1521 if (!capable(CAP_AUDIT_READ))
1527 static int __net_init audit_net_init(struct net *net)
1529 struct netlink_kernel_cfg cfg = {
1530 .input = audit_receive,
1532 .flags = NL_CFG_F_NONROOT_RECV,
1533 .groups = AUDIT_NLGRP_MAX,
1536 struct audit_net *aunet = net_generic(net, audit_net_id);
1538 aunet->sk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
1539 if (aunet->sk == NULL) {
1540 audit_panic("cannot initialize netlink socket in namespace");
1543 /* limit the timeout in case auditd is blocked/stopped */
1544 aunet->sk->sk_sndtimeo = HZ / 10;
1549 static void __net_exit audit_net_exit(struct net *net)
1551 struct audit_net *aunet = net_generic(net, audit_net_id);
1553 /* NOTE: you would think that we would want to check the auditd
1554 * connection and potentially reset it here if it lives in this
1555 * namespace, but since the auditd connection tracking struct holds a
1556 * reference to this namespace (see auditd_set()) we are only ever
1557 * going to get here after that connection has been released */
1559 netlink_kernel_release(aunet->sk);
1562 static struct pernet_operations audit_net_ops __net_initdata = {
1563 .init = audit_net_init,
1564 .exit = audit_net_exit,
1565 .id = &audit_net_id,
1566 .size = sizeof(struct audit_net),
1569 /* Initialize audit support at boot time. */
1570 static int __init audit_init(void)
1574 if (audit_initialized == AUDIT_DISABLED)
1577 audit_buffer_cache = kmem_cache_create("audit_buffer",
1578 sizeof(struct audit_buffer),
1579 0, SLAB_PANIC, NULL);
1581 skb_queue_head_init(&audit_queue);
1582 skb_queue_head_init(&audit_retry_queue);
1583 skb_queue_head_init(&audit_hold_queue);
1585 for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
1586 INIT_LIST_HEAD(&audit_inode_hash[i]);
1588 pr_info("initializing netlink subsys (%s)\n",
1589 audit_default ? "enabled" : "disabled");
1590 register_pernet_subsys(&audit_net_ops);
1592 audit_initialized = AUDIT_INITIALIZED;
1594 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
1595 if (IS_ERR(kauditd_task)) {
1596 int err = PTR_ERR(kauditd_task);
1597 panic("audit: failed to start the kauditd thread (%d)\n", err);
1600 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL,
1601 "state=initialized audit_enabled=%u res=1",
1606 __initcall(audit_init);
1608 /* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
1609 static int __init audit_enable(char *str)
1611 audit_default = !!simple_strtol(str, NULL, 0);
1613 audit_initialized = AUDIT_DISABLED;
1614 audit_enabled = audit_default;
1615 audit_ever_enabled = !!audit_enabled;
1617 pr_info("%s\n", audit_default ?
1618 "enabled (after initialization)" : "disabled (until reboot)");
1622 __setup("audit=", audit_enable);
1624 /* Process kernel command-line parameter at boot time.
1625 * audit_backlog_limit=<n> */
1626 static int __init audit_backlog_limit_set(char *str)
1628 u32 audit_backlog_limit_arg;
1630 pr_info("audit_backlog_limit: ");
1631 if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
1632 pr_cont("using default of %u, unable to parse %s\n",
1633 audit_backlog_limit, str);
1637 audit_backlog_limit = audit_backlog_limit_arg;
1638 pr_cont("%d\n", audit_backlog_limit);
1642 __setup("audit_backlog_limit=", audit_backlog_limit_set);
1644 static void audit_buffer_free(struct audit_buffer *ab)
1650 kmem_cache_free(audit_buffer_cache, ab);
1653 static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx,
1654 gfp_t gfp_mask, int type)
1656 struct audit_buffer *ab;
1658 ab = kmem_cache_alloc(audit_buffer_cache, gfp_mask);
1662 ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
1665 if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0))
1669 ab->gfp_mask = gfp_mask;
1674 audit_buffer_free(ab);
1679 * audit_serial - compute a serial number for the audit record
1681 * Compute a serial number for the audit record. Audit records are
1682 * written to user-space as soon as they are generated, so a complete
1683 * audit record may be written in several pieces. The timestamp of the
1684 * record and this serial number are used by the user-space tools to
1685 * determine which pieces belong to the same audit record. The
1686 * (timestamp,serial) tuple is unique for each syscall and is live from
1687 * syscall entry to syscall exit.
1689 * NOTE: Another possibility is to store the formatted records off the
1690 * audit context (for those records that have a context), and emit them
1691 * all at syscall exit. However, this could delay the reporting of
1692 * significant errors until syscall exit (or never, if the system
1695 unsigned int audit_serial(void)
1697 static atomic_t serial = ATOMIC_INIT(0);
1699 return atomic_add_return(1, &serial);
1702 static inline void audit_get_stamp(struct audit_context *ctx,
1703 struct timespec64 *t, unsigned int *serial)
1705 if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
1706 *t = current_kernel_time64();
1707 *serial = audit_serial();
1712 * audit_log_start - obtain an audit buffer
1713 * @ctx: audit_context (may be NULL)
1714 * @gfp_mask: type of allocation
1715 * @type: audit message type
1717 * Returns audit_buffer pointer on success or NULL on error.
1719 * Obtain an audit buffer. This routine does locking to obtain the
1720 * audit buffer, but then no locking is required for calls to
1721 * audit_log_*format. If the task (ctx) is a task that is currently in a
1722 * syscall, then the syscall is marked as auditable and an audit record
1723 * will be written at syscall exit. If there is no associated task, then
1724 * task context (ctx) should be NULL.
1726 struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1729 struct audit_buffer *ab;
1730 struct timespec64 t;
1731 unsigned int uninitialized_var(serial);
1733 if (audit_initialized != AUDIT_INITIALIZED)
1736 if (unlikely(!audit_filter(type, AUDIT_FILTER_TYPE)))
1739 /* NOTE: don't ever fail/sleep on these two conditions:
1740 * 1. auditd generated record - since we need auditd to drain the
1741 * queue; also, when we are checking for auditd, compare PIDs using
1742 * task_tgid_vnr() since auditd_pid is set in audit_receive_msg()
1743 * using a PID anchored in the caller's namespace
1744 * 2. generator holding the audit_cmd_mutex - we don't want to block
1745 * while holding the mutex */
1746 if (!(auditd_test_task(current) ||
1747 (current == __mutex_owner(&audit_cmd_mutex)))) {
1748 long stime = audit_backlog_wait_time;
1750 while (audit_backlog_limit &&
1751 (skb_queue_len(&audit_queue) > audit_backlog_limit)) {
1752 /* wake kauditd to try and flush the queue */
1753 wake_up_interruptible(&kauditd_wait);
1755 /* sleep if we are allowed and we haven't exhausted our
1756 * backlog wait limit */
1757 if (gfpflags_allow_blocking(gfp_mask) && (stime > 0)) {
1758 DECLARE_WAITQUEUE(wait, current);
1760 add_wait_queue_exclusive(&audit_backlog_wait,
1762 set_current_state(TASK_UNINTERRUPTIBLE);
1763 stime = schedule_timeout(stime);
1764 remove_wait_queue(&audit_backlog_wait, &wait);
1766 if (audit_rate_check() && printk_ratelimit())
1767 pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
1768 skb_queue_len(&audit_queue),
1769 audit_backlog_limit);
1770 audit_log_lost("backlog limit exceeded");
1776 ab = audit_buffer_alloc(ctx, gfp_mask, type);
1778 audit_log_lost("out of memory in audit_log_start");
1782 audit_get_stamp(ab->ctx, &t, &serial);
1783 audit_log_format(ab, "audit(%llu.%03lu:%u): ",
1784 (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
1790 * audit_expand - expand skb in the audit buffer
1792 * @extra: space to add at tail of the skb
1794 * Returns 0 (no space) on failed expansion, or available space if
1797 static inline int audit_expand(struct audit_buffer *ab, int extra)
1799 struct sk_buff *skb = ab->skb;
1800 int oldtail = skb_tailroom(skb);
1801 int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1802 int newtail = skb_tailroom(skb);
1805 audit_log_lost("out of memory in audit_expand");
1809 skb->truesize += newtail - oldtail;
1814 * Format an audit message into the audit buffer. If there isn't enough
1815 * room in the audit buffer, more room will be allocated and vsnprint
1816 * will be called a second time. Currently, we assume that a printk
1817 * can't format message larger than 1024 bytes, so we don't either.
1819 static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1823 struct sk_buff *skb;
1831 avail = skb_tailroom(skb);
1833 avail = audit_expand(ab, AUDIT_BUFSIZ);
1837 va_copy(args2, args);
1838 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1840 /* The printk buffer is 1024 bytes long, so if we get
1841 * here and AUDIT_BUFSIZ is at least 1024, then we can
1842 * log everything that printk could have logged. */
1843 avail = audit_expand(ab,
1844 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1847 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1858 * audit_log_format - format a message into the audit buffer.
1860 * @fmt: format string
1861 * @...: optional parameters matching @fmt string
1863 * All the work is done in audit_log_vformat.
1865 void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1871 va_start(args, fmt);
1872 audit_log_vformat(ab, fmt, args);
1877 * audit_log_n_hex - convert a buffer to hex and append it to the audit skb
1878 * @ab: the audit_buffer
1879 * @buf: buffer to convert to hex
1880 * @len: length of @buf to be converted
1882 * No return value; failure to expand is silently ignored.
1884 * This function will take the passed buf and convert it into a string of
1885 * ascii hex digits. The new string is placed onto the skb.
1887 void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
1890 int i, avail, new_len;
1892 struct sk_buff *skb;
1899 avail = skb_tailroom(skb);
1901 if (new_len >= avail) {
1902 /* Round the buffer request up to the next multiple */
1903 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1904 avail = audit_expand(ab, new_len);
1909 ptr = skb_tail_pointer(skb);
1910 for (i = 0; i < len; i++)
1911 ptr = hex_byte_pack_upper(ptr, buf[i]);
1913 skb_put(skb, len << 1); /* new string is twice the old string */
1917 * Format a string of no more than slen characters into the audit buffer,
1918 * enclosed in quote marks.
1920 void audit_log_n_string(struct audit_buffer *ab, const char *string,
1925 struct sk_buff *skb;
1932 avail = skb_tailroom(skb);
1933 new_len = slen + 3; /* enclosing quotes + null terminator */
1934 if (new_len > avail) {
1935 avail = audit_expand(ab, new_len);
1939 ptr = skb_tail_pointer(skb);
1941 memcpy(ptr, string, slen);
1945 skb_put(skb, slen + 2); /* don't include null terminator */
1949 * audit_string_contains_control - does a string need to be logged in hex
1950 * @string: string to be checked
1951 * @len: max length of the string to check
1953 bool audit_string_contains_control(const char *string, size_t len)
1955 const unsigned char *p;
1956 for (p = string; p < (const unsigned char *)string + len; p++) {
1957 if (*p == '"' || *p < 0x21 || *p > 0x7e)
1964 * audit_log_n_untrustedstring - log a string that may contain random characters
1966 * @len: length of string (not including trailing null)
1967 * @string: string to be logged
1969 * This code will escape a string that is passed to it if the string
1970 * contains a control character, unprintable character, double quote mark,
1971 * or a space. Unescaped strings will start and end with a double quote mark.
1972 * Strings that are escaped are printed in hex (2 digits per char).
1974 * The caller specifies the number of characters in the string to log, which may
1975 * or may not be the entire string.
1977 void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
1980 if (audit_string_contains_control(string, len))
1981 audit_log_n_hex(ab, string, len);
1983 audit_log_n_string(ab, string, len);
1987 * audit_log_untrustedstring - log a string that may contain random characters
1989 * @string: string to be logged
1991 * Same as audit_log_n_untrustedstring(), except that strlen is used to
1992 * determine string length.
1994 void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
1996 audit_log_n_untrustedstring(ab, string, strlen(string));
1999 /* This is a helper-function to print the escaped d_path */
2000 void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
2001 const struct path *path)
2006 audit_log_format(ab, "%s", prefix);
2008 /* We will allow 11 spaces for ' (deleted)' to be appended */
2009 pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
2011 audit_log_string(ab, "<no_memory>");
2014 p = d_path(path, pathname, PATH_MAX+11);
2015 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
2016 /* FIXME: can we save some information here? */
2017 audit_log_string(ab, "<too_long>");
2019 audit_log_untrustedstring(ab, p);
2023 void audit_log_session_info(struct audit_buffer *ab)
2025 unsigned int sessionid = audit_get_sessionid(current);
2026 uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
2028 audit_log_format(ab, " auid=%u ses=%u", auid, sessionid);
2031 void audit_log_key(struct audit_buffer *ab, char *key)
2033 audit_log_format(ab, " key=");
2035 audit_log_untrustedstring(ab, key);
2037 audit_log_format(ab, "(null)");
2040 void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap)
2044 audit_log_format(ab, " %s=", prefix);
2045 CAP_FOR_EACH_U32(i) {
2046 audit_log_format(ab, "%08x",
2047 cap->cap[CAP_LAST_U32 - i]);
2051 static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
2053 audit_log_cap(ab, "cap_fp", &name->fcap.permitted);
2054 audit_log_cap(ab, "cap_fi", &name->fcap.inheritable);
2055 audit_log_format(ab, " cap_fe=%d cap_fver=%x",
2056 name->fcap.fE, name->fcap_ver);
2059 static inline int audit_copy_fcaps(struct audit_names *name,
2060 const struct dentry *dentry)
2062 struct cpu_vfs_cap_data caps;
2068 rc = get_vfs_caps_from_disk(dentry, &caps);
2072 name->fcap.permitted = caps.permitted;
2073 name->fcap.inheritable = caps.inheritable;
2074 name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
2075 name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >>
2076 VFS_CAP_REVISION_SHIFT;
2081 /* Copy inode data into an audit_names. */
2082 void audit_copy_inode(struct audit_names *name, const struct dentry *dentry,
2083 struct inode *inode)
2085 name->ino = inode->i_ino;
2086 name->dev = inode->i_sb->s_dev;
2087 name->mode = inode->i_mode;
2088 name->uid = inode->i_uid;
2089 name->gid = inode->i_gid;
2090 name->rdev = inode->i_rdev;
2091 security_inode_getsecid(inode, &name->osid);
2092 audit_copy_fcaps(name, dentry);
2096 * audit_log_name - produce AUDIT_PATH record from struct audit_names
2097 * @context: audit_context for the task
2098 * @n: audit_names structure with reportable details
2099 * @path: optional path to report instead of audit_names->name
2100 * @record_num: record number to report when handling a list of names
2101 * @call_panic: optional pointer to int that will be updated if secid fails
2103 void audit_log_name(struct audit_context *context, struct audit_names *n,
2104 const struct path *path, int record_num, int *call_panic)
2106 struct audit_buffer *ab;
2107 ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH);
2111 audit_log_format(ab, "item=%d", record_num);
2114 audit_log_d_path(ab, " name=", path);
2116 switch (n->name_len) {
2117 case AUDIT_NAME_FULL:
2118 /* log the full path */
2119 audit_log_format(ab, " name=");
2120 audit_log_untrustedstring(ab, n->name->name);
2123 /* name was specified as a relative path and the
2124 * directory component is the cwd */
2125 audit_log_d_path(ab, " name=", &context->pwd);
2128 /* log the name's directory component */
2129 audit_log_format(ab, " name=");
2130 audit_log_n_untrustedstring(ab, n->name->name,
2134 audit_log_format(ab, " name=(null)");
2136 if (n->ino != AUDIT_INO_UNSET)
2137 audit_log_format(ab, " inode=%lu"
2138 " dev=%02x:%02x mode=%#ho"
2139 " ouid=%u ogid=%u rdev=%02x:%02x",
2144 from_kuid(&init_user_ns, n->uid),
2145 from_kgid(&init_user_ns, n->gid),
2151 if (security_secid_to_secctx(
2152 n->osid, &ctx, &len)) {
2153 audit_log_format(ab, " osid=%u", n->osid);
2157 audit_log_format(ab, " obj=%s", ctx);
2158 security_release_secctx(ctx, len);
2162 /* log the audit_names record type */
2163 audit_log_format(ab, " nametype=");
2165 case AUDIT_TYPE_NORMAL:
2166 audit_log_format(ab, "NORMAL");
2168 case AUDIT_TYPE_PARENT:
2169 audit_log_format(ab, "PARENT");
2171 case AUDIT_TYPE_CHILD_DELETE:
2172 audit_log_format(ab, "DELETE");
2174 case AUDIT_TYPE_CHILD_CREATE:
2175 audit_log_format(ab, "CREATE");
2178 audit_log_format(ab, "UNKNOWN");
2182 audit_log_fcaps(ab, n);
2186 int audit_log_task_context(struct audit_buffer *ab)
2193 security_task_getsecid(current, &sid);
2197 error = security_secid_to_secctx(sid, &ctx, &len);
2199 if (error != -EINVAL)
2204 audit_log_format(ab, " subj=%s", ctx);
2205 security_release_secctx(ctx, len);
2209 audit_panic("error in audit_log_task_context");
2212 EXPORT_SYMBOL(audit_log_task_context);
2214 void audit_log_d_path_exe(struct audit_buffer *ab,
2215 struct mm_struct *mm)
2217 struct file *exe_file;
2222 exe_file = get_mm_exe_file(mm);
2226 audit_log_d_path(ab, " exe=", &exe_file->f_path);
2230 audit_log_format(ab, " exe=(null)");
2233 struct tty_struct *audit_get_tty(struct task_struct *tsk)
2235 struct tty_struct *tty = NULL;
2236 unsigned long flags;
2238 spin_lock_irqsave(&tsk->sighand->siglock, flags);
2240 tty = tty_kref_get(tsk->signal->tty);
2241 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
2245 void audit_put_tty(struct tty_struct *tty)
2250 void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
2252 const struct cred *cred;
2253 char comm[sizeof(tsk->comm)];
2254 struct tty_struct *tty;
2259 /* tsk == current */
2260 cred = current_cred();
2261 tty = audit_get_tty(tsk);
2262 audit_log_format(ab,
2263 " ppid=%d pid=%d auid=%u uid=%u gid=%u"
2264 " euid=%u suid=%u fsuid=%u"
2265 " egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
2268 from_kuid(&init_user_ns, audit_get_loginuid(tsk)),
2269 from_kuid(&init_user_ns, cred->uid),
2270 from_kgid(&init_user_ns, cred->gid),
2271 from_kuid(&init_user_ns, cred->euid),
2272 from_kuid(&init_user_ns, cred->suid),
2273 from_kuid(&init_user_ns, cred->fsuid),
2274 from_kgid(&init_user_ns, cred->egid),
2275 from_kgid(&init_user_ns, cred->sgid),
2276 from_kgid(&init_user_ns, cred->fsgid),
2277 tty ? tty_name(tty) : "(none)",
2278 audit_get_sessionid(tsk));
2280 audit_log_format(ab, " comm=");
2281 audit_log_untrustedstring(ab, get_task_comm(comm, tsk));
2282 audit_log_d_path_exe(ab, tsk->mm);
2283 audit_log_task_context(ab);
2285 EXPORT_SYMBOL(audit_log_task_info);
2288 * audit_log_link_denied - report a link restriction denial
2289 * @operation: specific link operation
2290 * @link: the path that triggered the restriction
2292 void audit_log_link_denied(const char *operation, const struct path *link)
2294 struct audit_buffer *ab;
2295 struct audit_names *name;
2297 name = kzalloc(sizeof(*name), GFP_NOFS);
2301 /* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */
2302 ab = audit_log_start(current->audit_context, GFP_KERNEL,
2306 audit_log_format(ab, "op=%s", operation);
2307 audit_log_task_info(ab, current);
2308 audit_log_format(ab, " res=0");
2311 /* Generate AUDIT_PATH record with object. */
2312 name->type = AUDIT_TYPE_NORMAL;
2313 audit_copy_inode(name, link->dentry, d_backing_inode(link->dentry));
2314 audit_log_name(current->audit_context, name, link, 0, NULL);
2320 * audit_log_end - end one audit record
2321 * @ab: the audit_buffer
2323 * We can not do a netlink send inside an irq context because it blocks (last
2324 * arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a
2325 * queue and a tasklet is scheduled to remove them from the queue outside the
2326 * irq context. May be called in any context.
2328 void audit_log_end(struct audit_buffer *ab)
2330 struct sk_buff *skb;
2331 struct nlmsghdr *nlh;
2336 if (audit_rate_check()) {
2340 /* setup the netlink header, see the comments in
2341 * kauditd_send_multicast_skb() for length quirks */
2342 nlh = nlmsg_hdr(skb);
2343 nlh->nlmsg_len = skb->len - NLMSG_HDRLEN;
2345 /* queue the netlink packet and poke the kauditd thread */
2346 skb_queue_tail(&audit_queue, skb);
2347 wake_up_interruptible(&kauditd_wait);
2349 audit_log_lost("rate limit exceeded");
2351 audit_buffer_free(ab);
2355 * audit_log - Log an audit record
2356 * @ctx: audit context
2357 * @gfp_mask: type of allocation
2358 * @type: audit message type
2359 * @fmt: format string to use
2360 * @...: variable parameters matching the format string
2362 * This is a convenience function that calls audit_log_start,
2363 * audit_log_vformat, and audit_log_end. It may be called
2366 void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
2367 const char *fmt, ...)
2369 struct audit_buffer *ab;
2372 ab = audit_log_start(ctx, gfp_mask, type);
2374 va_start(args, fmt);
2375 audit_log_vformat(ab, fmt, args);
2381 #ifdef CONFIG_SECURITY
2383 * audit_log_secctx - Converts and logs SELinux context
2385 * @secid: security number
2387 * This is a helper function that calls security_secid_to_secctx to convert
2388 * secid to secctx and then adds the (converted) SELinux context to the audit
2389 * log by calling audit_log_format, thus also preventing leak of internal secid
2390 * to userspace. If secid cannot be converted audit_panic is called.
2392 void audit_log_secctx(struct audit_buffer *ab, u32 secid)
2397 if (security_secid_to_secctx(secid, &secctx, &len)) {
2398 audit_panic("Cannot convert secid to context");
2400 audit_log_format(ab, " obj=%s", secctx);
2401 security_release_secctx(secctx, len);
2404 EXPORT_SYMBOL(audit_log_secctx);
2407 EXPORT_SYMBOL(audit_log_start);
2408 EXPORT_SYMBOL(audit_log_end);
2409 EXPORT_SYMBOL(audit_log_format);
2410 EXPORT_SYMBOL(audit_log);