1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* audit.c -- Auditing support
3 * Gateway between the kernel (e.g., selinux) and the user-space audit daemon.
4 * System-call specific features have moved to auditsc.c
6 * Copyright 2003-2007 Red Hat Inc., Durham, North Carolina.
9 * Written by Rickard E. (Rik) Faith <faith@redhat.com>
11 * Goals: 1) Integrate fully with Security Modules.
12 * 2) Minimal run-time overhead:
13 * a) Minimal when syscall auditing is disabled (audit_enable=0).
14 * b) Small when syscall auditing is enabled and no audit record
15 * is generated (defer as much work as possible to record
17 * i) context is allocated,
18 * ii) names from getname are stored without a copy, and
19 * iii) inode information stored from path_lookup.
20 * 3) Ability to disable syscall auditing at boot time (audit=0).
21 * 4) Usable by other parts of the kernel (if audit_log* is called,
22 * then a syscall record will be generated automatically for the
24 * 5) Netlink interface to user-space.
25 * 6) Support low-overhead kernel-based filtering to minimize the
26 * information that must be passed to user-space.
28 * Audit userspace, documentation, tests, and bug/issue trackers:
29 * https://github.com/linux-audit
32 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
34 #include <linux/file.h>
35 #include <linux/init.h>
36 #include <linux/types.h>
37 #include <linux/atomic.h>
39 #include <linux/export.h>
40 #include <linux/slab.h>
41 #include <linux/err.h>
42 #include <linux/kthread.h>
43 #include <linux/kernel.h>
44 #include <linux/syscalls.h>
45 #include <linux/spinlock.h>
46 #include <linux/rcupdate.h>
47 #include <linux/mutex.h>
48 #include <linux/gfp.h>
49 #include <linux/pid.h>
51 #include <linux/audit.h>
54 #include <net/netlink.h>
55 #include <linux/skbuff.h>
56 #ifdef CONFIG_SECURITY
57 #include <linux/security.h>
59 #include <linux/freezer.h>
60 #include <linux/pid_namespace.h>
61 #include <net/netns/generic.h>
65 /* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
66 * (Initialization happens after skb_init is called.) */
67 #define AUDIT_DISABLED -1
68 #define AUDIT_UNINITIALIZED 0
69 #define AUDIT_INITIALIZED 1
70 static int audit_initialized;
72 u32 audit_enabled = AUDIT_OFF;
73 bool audit_ever_enabled = !!AUDIT_OFF;
75 EXPORT_SYMBOL_GPL(audit_enabled);
77 /* Default state when kernel boots without any parameters. */
78 static u32 audit_default = AUDIT_OFF;
80 /* If auditing cannot proceed, audit_failure selects what happens. */
81 static u32 audit_failure = AUDIT_FAIL_PRINTK;
83 /* private audit network namespace index */
84 static unsigned int audit_net_id;
87 * struct audit_net - audit private network namespace data
88 * @sk: communication socket
95 * struct auditd_connection - kernel/auditd connection state
97 * @portid: netlink portid
98 * @net: the associated network namespace
102 * This struct is RCU protected; you must either hold the RCU lock for reading
103 * or the associated spinlock for writing.
105 struct auditd_connection {
111 static struct auditd_connection __rcu *auditd_conn;
112 static DEFINE_SPINLOCK(auditd_conn_lock);
114 /* If audit_rate_limit is non-zero, limit the rate of sending audit records
115 * to that number per second. This prevents DoS attacks, but results in
116 * audit records being dropped. */
117 static u32 audit_rate_limit;
119 /* Number of outstanding audit_buffers allowed.
120 * When set to zero, this means unlimited. */
121 static u32 audit_backlog_limit = 64;
122 #define AUDIT_BACKLOG_WAIT_TIME (60 * HZ)
123 static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
125 /* The identity of the user shutting down the audit system. */
126 kuid_t audit_sig_uid = INVALID_UID;
127 pid_t audit_sig_pid = -1;
128 u32 audit_sig_sid = 0;
130 /* Records can be lost in several ways:
131 0) [suppressed in audit_alloc]
132 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
133 2) out of memory in audit_log_move [alloc_skb]
134 3) suppressed due to audit_rate_limit
135 4) suppressed due to audit_backlog_limit
137 static atomic_t audit_lost = ATOMIC_INIT(0);
139 /* Hash for inode-based rules */
140 struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
142 static struct kmem_cache *audit_buffer_cache;
144 /* queue msgs to send via kauditd_task */
145 static struct sk_buff_head audit_queue;
146 /* queue msgs due to temporary unicast send problems */
147 static struct sk_buff_head audit_retry_queue;
148 /* queue msgs waiting for new auditd connection */
149 static struct sk_buff_head audit_hold_queue;
151 /* queue servicing thread */
152 static struct task_struct *kauditd_task;
153 static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
155 /* waitqueue for callers who are blocked on the audit backlog */
156 static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
158 static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION,
163 static char *audit_feature_names[2] = {
164 "only_unset_loginuid",
165 "loginuid_immutable",
169 * struct audit_ctl_mutex - serialize requests from userspace
170 * @lock: the mutex used for locking
171 * @owner: the task which owns the lock
174 * This is the lock struct used to ensure we only process userspace requests
175 * in an orderly fashion. We can't simply use a mutex/lock here because we
176 * need to track lock ownership so we don't end up blocking the lock owner in
177 * audit_log_start() or similar.
179 static struct audit_ctl_mutex {
184 /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
185 * audit records. Since printk uses a 1024 byte buffer, this buffer
186 * should be at least that large. */
187 #define AUDIT_BUFSIZ 1024
189 /* The audit_buffer is used when formatting an audit record. The caller
190 * locks briefly to get the record off the freelist or to allocate the
191 * buffer, and locks briefly to send the buffer to the netlink layer or
192 * to place it on a transmit queue. Multiple audit_buffers can be in
193 * use simultaneously. */
194 struct audit_buffer {
195 struct sk_buff *skb; /* formatted skb ready to send */
196 struct audit_context *ctx; /* NULL or associated context */
207 * auditd_test_task - Check to see if a given task is an audit daemon
208 * @task: the task to check
211 * Return 1 if the task is a registered audit daemon, 0 otherwise.
213 int auditd_test_task(struct task_struct *task)
216 struct auditd_connection *ac;
219 ac = rcu_dereference(auditd_conn);
220 rc = (ac && ac->pid == task_tgid(task) ? 1 : 0);
227 * audit_ctl_lock - Take the audit control lock
229 void audit_ctl_lock(void)
231 mutex_lock(&audit_cmd_mutex.lock);
232 audit_cmd_mutex.owner = current;
236 * audit_ctl_unlock - Drop the audit control lock
238 void audit_ctl_unlock(void)
240 audit_cmd_mutex.owner = NULL;
241 mutex_unlock(&audit_cmd_mutex.lock);
245 * audit_ctl_owner_current - Test to see if the current task owns the lock
248 * Return true if the current task owns the audit control lock, false if it
249 * doesn't own the lock.
251 static bool audit_ctl_owner_current(void)
253 return (current == audit_cmd_mutex.owner);
257 * auditd_pid_vnr - Return the auditd PID relative to the namespace
260 * Returns the PID in relation to the namespace, 0 on failure.
262 static pid_t auditd_pid_vnr(void)
265 const struct auditd_connection *ac;
268 ac = rcu_dereference(auditd_conn);
272 pid = pid_vnr(ac->pid);
279 * audit_get_sk - Return the audit socket for the given network namespace
280 * @net: the destination network namespace
283 * Returns the sock pointer if valid, NULL otherwise. The caller must ensure
284 * that a reference is held for the network namespace while the sock is in use.
286 static struct sock *audit_get_sk(const struct net *net)
288 struct audit_net *aunet;
293 aunet = net_generic(net, audit_net_id);
297 void audit_panic(const char *message)
299 switch (audit_failure) {
300 case AUDIT_FAIL_SILENT:
302 case AUDIT_FAIL_PRINTK:
303 if (printk_ratelimit())
304 pr_err("%s\n", message);
306 case AUDIT_FAIL_PANIC:
307 panic("audit: %s\n", message);
312 static inline int audit_rate_check(void)
314 static unsigned long last_check = 0;
315 static int messages = 0;
316 static DEFINE_SPINLOCK(lock);
319 unsigned long elapsed;
322 if (!audit_rate_limit) return 1;
324 spin_lock_irqsave(&lock, flags);
325 if (++messages < audit_rate_limit) {
329 elapsed = now - last_check;
336 spin_unlock_irqrestore(&lock, flags);
342 * audit_log_lost - conditionally log lost audit message event
343 * @message: the message stating reason for lost audit message
345 * Emit at least 1 message per second, even if audit_rate_check is
347 * Always increment the lost messages counter.
349 void audit_log_lost(const char *message)
351 static unsigned long last_msg = 0;
352 static DEFINE_SPINLOCK(lock);
357 atomic_inc(&audit_lost);
359 print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
362 spin_lock_irqsave(&lock, flags);
364 if (now - last_msg > HZ) {
368 spin_unlock_irqrestore(&lock, flags);
372 if (printk_ratelimit())
373 pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
374 atomic_read(&audit_lost),
376 audit_backlog_limit);
377 audit_panic(message);
381 static int audit_log_config_change(char *function_name, u32 new, u32 old,
384 struct audit_buffer *ab;
387 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
390 audit_log_format(ab, "op=set %s=%u old=%u ", function_name, new, old);
391 audit_log_session_info(ab);
392 rc = audit_log_task_context(ab);
394 allow_changes = 0; /* Something weird, deny request */
395 audit_log_format(ab, " res=%d", allow_changes);
400 static int audit_do_config_change(char *function_name, u32 *to_change, u32 new)
402 int allow_changes, rc = 0;
403 u32 old = *to_change;
405 /* check if we are locked */
406 if (audit_enabled == AUDIT_LOCKED)
411 if (audit_enabled != AUDIT_OFF) {
412 rc = audit_log_config_change(function_name, new, old, allow_changes);
417 /* If we are allowed, make the change */
418 if (allow_changes == 1)
420 /* Not allowed, update reason */
426 static int audit_set_rate_limit(u32 limit)
428 return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit);
431 static int audit_set_backlog_limit(u32 limit)
433 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit);
436 static int audit_set_backlog_wait_time(u32 timeout)
438 return audit_do_config_change("audit_backlog_wait_time",
439 &audit_backlog_wait_time, timeout);
442 static int audit_set_enabled(u32 state)
445 if (state > AUDIT_LOCKED)
448 rc = audit_do_config_change("audit_enabled", &audit_enabled, state);
450 audit_ever_enabled |= !!state;
455 static int audit_set_failure(u32 state)
457 if (state != AUDIT_FAIL_SILENT
458 && state != AUDIT_FAIL_PRINTK
459 && state != AUDIT_FAIL_PANIC)
462 return audit_do_config_change("audit_failure", &audit_failure, state);
466 * auditd_conn_free - RCU helper to release an auditd connection struct
470 * Drop any references inside the auditd connection tracking struct and free
473 static void auditd_conn_free(struct rcu_head *rcu)
475 struct auditd_connection *ac;
477 ac = container_of(rcu, struct auditd_connection, rcu);
484 * auditd_set - Set/Reset the auditd connection state
486 * @portid: auditd netlink portid
487 * @net: auditd network namespace pointer
490 * This function will obtain and drop network namespace references as
491 * necessary. Returns zero on success, negative values on failure.
493 static int auditd_set(struct pid *pid, u32 portid, struct net *net)
496 struct auditd_connection *ac_old, *ac_new;
501 ac_new = kzalloc(sizeof(*ac_new), GFP_KERNEL);
504 ac_new->pid = get_pid(pid);
505 ac_new->portid = portid;
506 ac_new->net = get_net(net);
508 spin_lock_irqsave(&auditd_conn_lock, flags);
509 ac_old = rcu_dereference_protected(auditd_conn,
510 lockdep_is_held(&auditd_conn_lock));
511 rcu_assign_pointer(auditd_conn, ac_new);
512 spin_unlock_irqrestore(&auditd_conn_lock, flags);
515 call_rcu(&ac_old->rcu, auditd_conn_free);
521 * kauditd_print_skb - Print the audit record to the ring buffer
524 * Whatever the reason, this packet may not make it to the auditd connection
525 * so write it via printk so the information isn't completely lost.
527 static void kauditd_printk_skb(struct sk_buff *skb)
529 struct nlmsghdr *nlh = nlmsg_hdr(skb);
530 char *data = nlmsg_data(nlh);
532 if (nlh->nlmsg_type != AUDIT_EOE && printk_ratelimit())
533 pr_notice("type=%d %s\n", nlh->nlmsg_type, data);
537 * kauditd_rehold_skb - Handle a audit record send failure in the hold queue
541 * This should only be used by the kauditd_thread when it fails to flush the
544 static void kauditd_rehold_skb(struct sk_buff *skb)
546 /* put the record back in the queue at the same place */
547 skb_queue_head(&audit_hold_queue, skb);
551 * kauditd_hold_skb - Queue an audit record, waiting for auditd
555 * Queue the audit record, waiting for an instance of auditd. When this
556 * function is called we haven't given up yet on sending the record, but things
557 * are not looking good. The first thing we want to do is try to write the
558 * record via printk and then see if we want to try and hold on to the record
559 * and queue it, if we have room. If we want to hold on to the record, but we
560 * don't have room, record a record lost message.
562 static void kauditd_hold_skb(struct sk_buff *skb)
564 /* at this point it is uncertain if we will ever send this to auditd so
565 * try to send the message via printk before we go any further */
566 kauditd_printk_skb(skb);
568 /* can we just silently drop the message? */
569 if (!audit_default) {
574 /* if we have room, queue the message */
575 if (!audit_backlog_limit ||
576 skb_queue_len(&audit_hold_queue) < audit_backlog_limit) {
577 skb_queue_tail(&audit_hold_queue, skb);
581 /* we have no other options - drop the message */
582 audit_log_lost("kauditd hold queue overflow");
587 * kauditd_retry_skb - Queue an audit record, attempt to send again to auditd
591 * Not as serious as kauditd_hold_skb() as we still have a connected auditd,
592 * but for some reason we are having problems sending it audit records so
593 * queue the given record and attempt to resend.
595 static void kauditd_retry_skb(struct sk_buff *skb)
597 /* NOTE: because records should only live in the retry queue for a
598 * short period of time, before either being sent or moved to the hold
599 * queue, we don't currently enforce a limit on this queue */
600 skb_queue_tail(&audit_retry_queue, skb);
604 * auditd_reset - Disconnect the auditd connection
605 * @ac: auditd connection state
608 * Break the auditd/kauditd connection and move all the queued records into the
609 * hold queue in case auditd reconnects. It is important to note that the @ac
610 * pointer should never be dereferenced inside this function as it may be NULL
611 * or invalid, you can only compare the memory address! If @ac is NULL then
612 * the connection will always be reset.
614 static void auditd_reset(const struct auditd_connection *ac)
618 struct auditd_connection *ac_old;
620 /* if it isn't already broken, break the connection */
621 spin_lock_irqsave(&auditd_conn_lock, flags);
622 ac_old = rcu_dereference_protected(auditd_conn,
623 lockdep_is_held(&auditd_conn_lock));
624 if (ac && ac != ac_old) {
625 /* someone already registered a new auditd connection */
626 spin_unlock_irqrestore(&auditd_conn_lock, flags);
629 rcu_assign_pointer(auditd_conn, NULL);
630 spin_unlock_irqrestore(&auditd_conn_lock, flags);
633 call_rcu(&ac_old->rcu, auditd_conn_free);
635 /* flush the retry queue to the hold queue, but don't touch the main
636 * queue since we need to process that normally for multicast */
637 while ((skb = skb_dequeue(&audit_retry_queue)))
638 kauditd_hold_skb(skb);
642 * auditd_send_unicast_skb - Send a record via unicast to auditd
646 * Send a skb to the audit daemon, returns positive/zero values on success and
647 * negative values on failure; in all cases the skb will be consumed by this
648 * function. If the send results in -ECONNREFUSED the connection with auditd
649 * will be reset. This function may sleep so callers should not hold any locks
650 * where this would cause a problem.
652 static int auditd_send_unicast_skb(struct sk_buff *skb)
658 struct auditd_connection *ac;
660 /* NOTE: we can't call netlink_unicast while in the RCU section so
661 * take a reference to the network namespace and grab local
662 * copies of the namespace, the sock, and the portid; the
663 * namespace and sock aren't going to go away while we hold a
664 * reference and if the portid does become invalid after the RCU
665 * section netlink_unicast() should safely return an error */
668 ac = rcu_dereference(auditd_conn);
675 net = get_net(ac->net);
676 sk = audit_get_sk(net);
680 rc = netlink_unicast(sk, skb, portid, 0);
688 if (ac && rc == -ECONNREFUSED)
694 * kauditd_send_queue - Helper for kauditd_thread to flush skb queues
695 * @sk: the sending sock
696 * @portid: the netlink destination
697 * @queue: the skb queue to process
698 * @retry_limit: limit on number of netlink unicast failures
699 * @skb_hook: per-skb hook for additional processing
700 * @err_hook: hook called if the skb fails the netlink unicast send
703 * Run through the given queue and attempt to send the audit records to auditd,
704 * returns zero on success, negative values on failure. It is up to the caller
705 * to ensure that the @sk is valid for the duration of this function.
708 static int kauditd_send_queue(struct sock *sk, u32 portid,
709 struct sk_buff_head *queue,
710 unsigned int retry_limit,
711 void (*skb_hook)(struct sk_buff *skb),
712 void (*err_hook)(struct sk_buff *skb))
716 static unsigned int failed = 0;
718 /* NOTE: kauditd_thread takes care of all our locking, we just use
719 * the netlink info passed to us (e.g. sk and portid) */
721 while ((skb = skb_dequeue(queue))) {
722 /* call the skb_hook for each skb we touch */
726 /* can we send to anyone via unicast? */
733 /* grab an extra skb reference in case of error */
735 rc = netlink_unicast(sk, skb, portid, 0);
737 /* fatal failure for our queue flush attempt? */
738 if (++failed >= retry_limit ||
739 rc == -ECONNREFUSED || rc == -EPERM) {
740 /* yes - error processing for the queue */
746 /* keep processing with the skb_hook */
749 /* no - requeue to preserve ordering */
750 skb_queue_head(queue, skb);
752 /* it worked - drop the extra reference and continue */
759 return (rc >= 0 ? 0 : rc);
763 * kauditd_send_multicast_skb - Send a record to any multicast listeners
767 * Write a multicast message to anyone listening in the initial network
768 * namespace. This function doesn't consume an skb as might be expected since
769 * it has to copy it anyways.
771 static void kauditd_send_multicast_skb(struct sk_buff *skb)
773 struct sk_buff *copy;
774 struct sock *sock = audit_get_sk(&init_net);
775 struct nlmsghdr *nlh;
777 /* NOTE: we are not taking an additional reference for init_net since
778 * we don't have to worry about it going away */
780 if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
784 * The seemingly wasteful skb_copy() rather than bumping the refcount
785 * using skb_get() is necessary because non-standard mods are made to
786 * the skb by the original kaudit unicast socket send routine. The
787 * existing auditd daemon assumes this breakage. Fixing this would
788 * require co-ordinating a change in the established protocol between
789 * the kaudit kernel subsystem and the auditd userspace code. There is
790 * no reason for new multicast clients to continue with this
793 copy = skb_copy(skb, GFP_KERNEL);
796 nlh = nlmsg_hdr(copy);
797 nlh->nlmsg_len = skb->len;
799 nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL);
803 * kauditd_thread - Worker thread to send audit records to userspace
806 static int kauditd_thread(void *dummy)
810 struct net *net = NULL;
811 struct sock *sk = NULL;
812 struct auditd_connection *ac;
814 #define UNICAST_RETRIES 5
817 while (!kthread_should_stop()) {
818 /* NOTE: see the lock comments in auditd_send_unicast_skb() */
820 ac = rcu_dereference(auditd_conn);
825 net = get_net(ac->net);
826 sk = audit_get_sk(net);
830 /* attempt to flush the hold queue */
831 rc = kauditd_send_queue(sk, portid,
832 &audit_hold_queue, UNICAST_RETRIES,
833 NULL, kauditd_rehold_skb);
840 /* attempt to flush the retry queue */
841 rc = kauditd_send_queue(sk, portid,
842 &audit_retry_queue, UNICAST_RETRIES,
843 NULL, kauditd_hold_skb);
851 /* process the main queue - do the multicast send and attempt
852 * unicast, dump failed record sends to the retry queue; if
853 * sk == NULL due to previous failures we will just do the
854 * multicast send and move the record to the hold queue */
855 rc = kauditd_send_queue(sk, portid, &audit_queue, 1,
856 kauditd_send_multicast_skb,
858 kauditd_retry_skb : kauditd_hold_skb));
863 /* drop our netns reference, no auditd sends past this line */
869 /* we have processed all the queues so wake everyone */
870 wake_up(&audit_backlog_wait);
872 /* NOTE: we want to wake up if there is anything on the queue,
873 * regardless of if an auditd is connected, as we need to
874 * do the multicast send and rotate records from the
875 * main queue to the retry/hold queues */
876 wait_event_freezable(kauditd_wait,
877 (skb_queue_len(&audit_queue) ? 1 : 0));
883 int audit_send_list_thread(void *_dest)
885 struct audit_netlink_list *dest = _dest;
887 struct sock *sk = audit_get_sk(dest->net);
889 /* wait for parent to finish and send an ACK */
893 while ((skb = __skb_dequeue(&dest->q)) != NULL)
894 netlink_unicast(sk, skb, dest->portid, 0);
902 struct sk_buff *audit_make_reply(int seq, int type, int done,
903 int multi, const void *payload, int size)
906 struct nlmsghdr *nlh;
908 int flags = multi ? NLM_F_MULTI : 0;
909 int t = done ? NLMSG_DONE : type;
911 skb = nlmsg_new(size, GFP_KERNEL);
915 nlh = nlmsg_put(skb, 0, seq, t, size, flags);
918 data = nlmsg_data(nlh);
919 memcpy(data, payload, size);
927 static void audit_free_reply(struct audit_reply *reply)
933 kfree_skb(reply->skb);
939 static int audit_send_reply_thread(void *arg)
941 struct audit_reply *reply = (struct audit_reply *)arg;
946 /* Ignore failure. It'll only happen if the sender goes away,
947 because our timeout is set to infinite. */
948 netlink_unicast(audit_get_sk(reply->net), reply->skb, reply->portid, 0);
950 audit_free_reply(reply);
955 * audit_send_reply - send an audit reply message via netlink
956 * @request_skb: skb of request we are replying to (used to target the reply)
957 * @seq: sequence number
958 * @type: audit message type
959 * @done: done (last) flag
960 * @multi: multi-part message flag
961 * @payload: payload data
962 * @size: payload size
964 * Allocates a skb, builds the netlink message, and sends it to the port id.
966 static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
967 int multi, const void *payload, int size)
969 struct task_struct *tsk;
970 struct audit_reply *reply;
972 reply = kzalloc(sizeof(*reply), GFP_KERNEL);
976 reply->skb = audit_make_reply(seq, type, done, multi, payload, size);
979 reply->net = get_net(sock_net(NETLINK_CB(request_skb).sk));
980 reply->portid = NETLINK_CB(request_skb).portid;
982 tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
989 audit_free_reply(reply);
993 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
996 static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
1000 /* Only support initial user namespace for now. */
1002 * We return ECONNREFUSED because it tricks userspace into thinking
1003 * that audit was not configured into the kernel. Lots of users
1004 * configure their PAM stack (because that's what the distro does)
1005 * to reject login if unable to send messages to audit. If we return
1006 * ECONNREFUSED the PAM stack thinks the kernel does not have audit
1007 * configured in and will let login proceed. If we return EPERM
1008 * userspace will reject all logins. This should be removed when we
1009 * support non init namespaces!!
1011 if (current_user_ns() != &init_user_ns)
1012 return -ECONNREFUSED;
1021 case AUDIT_GET_FEATURE:
1022 case AUDIT_SET_FEATURE:
1023 case AUDIT_LIST_RULES:
1024 case AUDIT_ADD_RULE:
1025 case AUDIT_DEL_RULE:
1026 case AUDIT_SIGNAL_INFO:
1030 case AUDIT_MAKE_EQUIV:
1031 /* Only support auditd and auditctl in initial pid namespace
1033 if (task_active_pid_ns(current) != &init_pid_ns)
1036 if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
1040 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1041 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1042 if (!netlink_capable(skb, CAP_AUDIT_WRITE))
1045 default: /* bad msg */
1052 static void audit_log_common_recv_msg(struct audit_context *context,
1053 struct audit_buffer **ab, u16 msg_type)
1055 uid_t uid = from_kuid(&init_user_ns, current_uid());
1056 pid_t pid = task_tgid_nr(current);
1058 if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
1063 *ab = audit_log_start(context, GFP_KERNEL, msg_type);
1066 audit_log_format(*ab, "pid=%d uid=%u ", pid, uid);
1067 audit_log_session_info(*ab);
1068 audit_log_task_context(*ab);
1071 static inline void audit_log_user_recv_msg(struct audit_buffer **ab,
1074 audit_log_common_recv_msg(NULL, ab, msg_type);
1077 int is_audit_feature_set(int i)
1079 return af.features & AUDIT_FEATURE_TO_MASK(i);
1083 static int audit_get_feature(struct sk_buff *skb)
1087 seq = nlmsg_hdr(skb)->nlmsg_seq;
1089 audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af));
1094 static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
1095 u32 old_lock, u32 new_lock, int res)
1097 struct audit_buffer *ab;
1099 if (audit_enabled == AUDIT_OFF)
1102 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_FEATURE_CHANGE);
1105 audit_log_task_info(ab);
1106 audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
1107 audit_feature_names[which], !!old_feature, !!new_feature,
1108 !!old_lock, !!new_lock, res);
1112 static int audit_set_feature(struct audit_features *uaf)
1116 BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
1118 /* if there is ever a version 2 we should handle that here */
1120 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1121 u32 feature = AUDIT_FEATURE_TO_MASK(i);
1122 u32 old_feature, new_feature, old_lock, new_lock;
1124 /* if we are not changing this feature, move along */
1125 if (!(feature & uaf->mask))
1128 old_feature = af.features & feature;
1129 new_feature = uaf->features & feature;
1130 new_lock = (uaf->lock | af.lock) & feature;
1131 old_lock = af.lock & feature;
1133 /* are we changing a locked feature? */
1134 if (old_lock && (new_feature != old_feature)) {
1135 audit_log_feature_change(i, old_feature, new_feature,
1136 old_lock, new_lock, 0);
1140 /* nothing invalid, do the changes */
1141 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1142 u32 feature = AUDIT_FEATURE_TO_MASK(i);
1143 u32 old_feature, new_feature, old_lock, new_lock;
1145 /* if we are not changing this feature, move along */
1146 if (!(feature & uaf->mask))
1149 old_feature = af.features & feature;
1150 new_feature = uaf->features & feature;
1151 old_lock = af.lock & feature;
1152 new_lock = (uaf->lock | af.lock) & feature;
1154 if (new_feature != old_feature)
1155 audit_log_feature_change(i, old_feature, new_feature,
1156 old_lock, new_lock, 1);
1159 af.features |= feature;
1161 af.features &= ~feature;
1162 af.lock |= new_lock;
1168 static int audit_replace(struct pid *pid)
1171 struct sk_buff *skb;
1173 pvnr = pid_vnr(pid);
1174 skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pvnr, sizeof(pvnr));
1177 return auditd_send_unicast_skb(skb);
1180 static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
1186 struct audit_buffer *ab;
1187 u16 msg_type = nlh->nlmsg_type;
1188 struct audit_sig_info *sig_data;
1192 err = audit_netlink_ok(skb, msg_type);
1196 seq = nlh->nlmsg_seq;
1197 data = nlmsg_data(nlh);
1198 data_len = nlmsg_len(nlh);
1202 struct audit_status s;
1203 memset(&s, 0, sizeof(s));
1204 s.enabled = audit_enabled;
1205 s.failure = audit_failure;
1206 /* NOTE: use pid_vnr() so the PID is relative to the current
1208 s.pid = auditd_pid_vnr();
1209 s.rate_limit = audit_rate_limit;
1210 s.backlog_limit = audit_backlog_limit;
1211 s.lost = atomic_read(&audit_lost);
1212 s.backlog = skb_queue_len(&audit_queue);
1213 s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL;
1214 s.backlog_wait_time = audit_backlog_wait_time;
1215 audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
1219 struct audit_status s;
1220 memset(&s, 0, sizeof(s));
1221 /* guard against past and future API changes */
1222 memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
1223 if (s.mask & AUDIT_STATUS_ENABLED) {
1224 err = audit_set_enabled(s.enabled);
1228 if (s.mask & AUDIT_STATUS_FAILURE) {
1229 err = audit_set_failure(s.failure);
1233 if (s.mask & AUDIT_STATUS_PID) {
1234 /* NOTE: we are using the vnr PID functions below
1235 * because the s.pid value is relative to the
1236 * namespace of the caller; at present this
1237 * doesn't matter much since you can really only
1238 * run auditd from the initial pid namespace, but
1239 * something to keep in mind if this changes */
1240 pid_t new_pid = s.pid;
1242 struct pid *req_pid = task_tgid(current);
1244 /* Sanity check - PID values must match. Setting
1245 * pid to 0 is how auditd ends auditing. */
1246 if (new_pid && (new_pid != pid_vnr(req_pid)))
1249 /* test the auditd connection */
1250 audit_replace(req_pid);
1252 auditd_pid = auditd_pid_vnr();
1254 /* replacing a healthy auditd is not allowed */
1256 audit_log_config_change("audit_pid",
1257 new_pid, auditd_pid, 0);
1260 /* only current auditd can unregister itself */
1261 if (pid_vnr(req_pid) != auditd_pid) {
1262 audit_log_config_change("audit_pid",
1263 new_pid, auditd_pid, 0);
1269 /* register a new auditd connection */
1270 err = auditd_set(req_pid,
1271 NETLINK_CB(skb).portid,
1272 sock_net(NETLINK_CB(skb).sk));
1273 if (audit_enabled != AUDIT_OFF)
1274 audit_log_config_change("audit_pid",
1281 /* try to process any backlog */
1282 wake_up_interruptible(&kauditd_wait);
1284 if (audit_enabled != AUDIT_OFF)
1285 audit_log_config_change("audit_pid",
1289 /* unregister the auditd connection */
1293 if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
1294 err = audit_set_rate_limit(s.rate_limit);
1298 if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
1299 err = audit_set_backlog_limit(s.backlog_limit);
1303 if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
1304 if (sizeof(s) > (size_t)nlh->nlmsg_len)
1306 if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
1308 err = audit_set_backlog_wait_time(s.backlog_wait_time);
1312 if (s.mask == AUDIT_STATUS_LOST) {
1313 u32 lost = atomic_xchg(&audit_lost, 0);
1315 audit_log_config_change("lost", 0, lost, 1);
1320 case AUDIT_GET_FEATURE:
1321 err = audit_get_feature(skb);
1325 case AUDIT_SET_FEATURE:
1326 if (data_len < sizeof(struct audit_features))
1328 err = audit_set_feature(data);
1333 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1334 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1335 if (!audit_enabled && msg_type != AUDIT_USER_AVC)
1338 err = audit_filter(msg_type, AUDIT_FILTER_USER);
1339 if (err == 1) { /* match or error */
1343 if (msg_type == AUDIT_USER_TTY) {
1344 err = tty_audit_push();
1348 audit_log_user_recv_msg(&ab, msg_type);
1349 if (msg_type != AUDIT_USER_TTY) {
1350 /* ensure NULL termination */
1351 str[data_len - 1] = '\0';
1352 audit_log_format(ab, " msg='%.*s'",
1353 AUDIT_MESSAGE_TEXT_MAX,
1356 audit_log_format(ab, " data=");
1357 if (data_len > 0 && str[data_len - 1] == '\0')
1359 audit_log_n_untrustedstring(ab, str, data_len);
1364 case AUDIT_ADD_RULE:
1365 case AUDIT_DEL_RULE:
1366 if (data_len < sizeof(struct audit_rule_data))
1368 if (audit_enabled == AUDIT_LOCKED) {
1369 audit_log_common_recv_msg(audit_context(), &ab,
1370 AUDIT_CONFIG_CHANGE);
1371 audit_log_format(ab, " op=%s audit_enabled=%d res=0",
1372 msg_type == AUDIT_ADD_RULE ?
1373 "add_rule" : "remove_rule",
1378 err = audit_rule_change(msg_type, seq, data, data_len);
1380 case AUDIT_LIST_RULES:
1381 err = audit_list_rules_send(skb, seq);
1385 audit_log_common_recv_msg(audit_context(), &ab,
1386 AUDIT_CONFIG_CHANGE);
1387 audit_log_format(ab, " op=trim res=1");
1390 case AUDIT_MAKE_EQUIV: {
1393 size_t msglen = data_len;
1397 if (msglen < 2 * sizeof(u32))
1399 memcpy(sizes, bufp, 2 * sizeof(u32));
1400 bufp += 2 * sizeof(u32);
1401 msglen -= 2 * sizeof(u32);
1402 old = audit_unpack_string(&bufp, &msglen, sizes[0]);
1407 new = audit_unpack_string(&bufp, &msglen, sizes[1]);
1413 /* OK, here comes... */
1414 err = audit_tag_tree(old, new);
1416 audit_log_common_recv_msg(audit_context(), &ab,
1417 AUDIT_CONFIG_CHANGE);
1418 audit_log_format(ab, " op=make_equiv old=");
1419 audit_log_untrustedstring(ab, old);
1420 audit_log_format(ab, " new=");
1421 audit_log_untrustedstring(ab, new);
1422 audit_log_format(ab, " res=%d", !err);
1428 case AUDIT_SIGNAL_INFO:
1430 if (audit_sig_sid) {
1431 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
1435 sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
1438 security_release_secctx(ctx, len);
1441 sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
1442 sig_data->pid = audit_sig_pid;
1443 if (audit_sig_sid) {
1444 memcpy(sig_data->ctx, ctx, len);
1445 security_release_secctx(ctx, len);
1447 audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
1448 sig_data, sizeof(*sig_data) + len);
1451 case AUDIT_TTY_GET: {
1452 struct audit_tty_status s;
1455 t = READ_ONCE(current->signal->audit_tty);
1456 s.enabled = t & AUDIT_TTY_ENABLE;
1457 s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1459 audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
1462 case AUDIT_TTY_SET: {
1463 struct audit_tty_status s, old;
1464 struct audit_buffer *ab;
1467 memset(&s, 0, sizeof(s));
1468 /* guard against past and future API changes */
1469 memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
1470 /* check if new data is valid */
1471 if ((s.enabled != 0 && s.enabled != 1) ||
1472 (s.log_passwd != 0 && s.log_passwd != 1))
1476 t = READ_ONCE(current->signal->audit_tty);
1478 t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD);
1479 t = xchg(¤t->signal->audit_tty, t);
1481 old.enabled = t & AUDIT_TTY_ENABLE;
1482 old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1484 audit_log_common_recv_msg(audit_context(), &ab,
1485 AUDIT_CONFIG_CHANGE);
1486 audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
1487 " old-log_passwd=%d new-log_passwd=%d res=%d",
1488 old.enabled, s.enabled, old.log_passwd,
1489 s.log_passwd, !err);
1498 return err < 0 ? err : 0;
1502 * audit_receive - receive messages from a netlink control socket
1503 * @skb: the message buffer
1505 * Parse the provided skb and deal with any messages that may be present,
1506 * malformed skbs are discarded.
1508 static void audit_receive(struct sk_buff *skb)
1510 struct nlmsghdr *nlh;
1512 * len MUST be signed for nlmsg_next to be able to dec it below 0
1513 * if the nlmsg_len was not aligned
1518 nlh = nlmsg_hdr(skb);
1522 while (nlmsg_ok(nlh, len)) {
1523 err = audit_receive_msg(skb, nlh);
1524 /* if err or if this message says it wants a response */
1525 if (err || (nlh->nlmsg_flags & NLM_F_ACK))
1526 netlink_ack(skb, nlh, err, NULL);
1528 nlh = nlmsg_next(nlh, &len);
1533 /* Run custom bind function on netlink socket group connect or bind requests. */
1534 static int audit_bind(struct net *net, int group)
1536 if (!capable(CAP_AUDIT_READ))
1542 static int __net_init audit_net_init(struct net *net)
1544 struct netlink_kernel_cfg cfg = {
1545 .input = audit_receive,
1547 .flags = NL_CFG_F_NONROOT_RECV,
1548 .groups = AUDIT_NLGRP_MAX,
1551 struct audit_net *aunet = net_generic(net, audit_net_id);
1553 aunet->sk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
1554 if (aunet->sk == NULL) {
1555 audit_panic("cannot initialize netlink socket in namespace");
1558 aunet->sk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
1563 static void __net_exit audit_net_exit(struct net *net)
1565 struct audit_net *aunet = net_generic(net, audit_net_id);
1567 /* NOTE: you would think that we would want to check the auditd
1568 * connection and potentially reset it here if it lives in this
1569 * namespace, but since the auditd connection tracking struct holds a
1570 * reference to this namespace (see auditd_set()) we are only ever
1571 * going to get here after that connection has been released */
1573 netlink_kernel_release(aunet->sk);
1576 static struct pernet_operations audit_net_ops __net_initdata = {
1577 .init = audit_net_init,
1578 .exit = audit_net_exit,
1579 .id = &audit_net_id,
1580 .size = sizeof(struct audit_net),
1583 /* Initialize audit support at boot time. */
1584 static int __init audit_init(void)
1588 if (audit_initialized == AUDIT_DISABLED)
1591 audit_buffer_cache = kmem_cache_create("audit_buffer",
1592 sizeof(struct audit_buffer),
1593 0, SLAB_PANIC, NULL);
1595 skb_queue_head_init(&audit_queue);
1596 skb_queue_head_init(&audit_retry_queue);
1597 skb_queue_head_init(&audit_hold_queue);
1599 for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
1600 INIT_LIST_HEAD(&audit_inode_hash[i]);
1602 mutex_init(&audit_cmd_mutex.lock);
1603 audit_cmd_mutex.owner = NULL;
1605 pr_info("initializing netlink subsys (%s)\n",
1606 audit_default ? "enabled" : "disabled");
1607 register_pernet_subsys(&audit_net_ops);
1609 audit_initialized = AUDIT_INITIALIZED;
1611 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
1612 if (IS_ERR(kauditd_task)) {
1613 int err = PTR_ERR(kauditd_task);
1614 panic("audit: failed to start the kauditd thread (%d)\n", err);
1617 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL,
1618 "state=initialized audit_enabled=%u res=1",
1623 postcore_initcall(audit_init);
1626 * Process kernel command-line parameter at boot time.
1627 * audit={0|off} or audit={1|on}.
1629 static int __init audit_enable(char *str)
1631 if (!strcasecmp(str, "off") || !strcmp(str, "0"))
1632 audit_default = AUDIT_OFF;
1633 else if (!strcasecmp(str, "on") || !strcmp(str, "1"))
1634 audit_default = AUDIT_ON;
1636 pr_err("audit: invalid 'audit' parameter value (%s)\n", str);
1637 audit_default = AUDIT_ON;
1640 if (audit_default == AUDIT_OFF)
1641 audit_initialized = AUDIT_DISABLED;
1642 if (audit_set_enabled(audit_default))
1643 pr_err("audit: error setting audit state (%d)\n",
1646 pr_info("%s\n", audit_default ?
1647 "enabled (after initialization)" : "disabled (until reboot)");
1651 __setup("audit=", audit_enable);
1653 /* Process kernel command-line parameter at boot time.
1654 * audit_backlog_limit=<n> */
1655 static int __init audit_backlog_limit_set(char *str)
1657 u32 audit_backlog_limit_arg;
1659 pr_info("audit_backlog_limit: ");
1660 if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
1661 pr_cont("using default of %u, unable to parse %s\n",
1662 audit_backlog_limit, str);
1666 audit_backlog_limit = audit_backlog_limit_arg;
1667 pr_cont("%d\n", audit_backlog_limit);
1671 __setup("audit_backlog_limit=", audit_backlog_limit_set);
1673 static void audit_buffer_free(struct audit_buffer *ab)
1679 kmem_cache_free(audit_buffer_cache, ab);
1682 static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx,
1683 gfp_t gfp_mask, int type)
1685 struct audit_buffer *ab;
1687 ab = kmem_cache_alloc(audit_buffer_cache, gfp_mask);
1691 ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
1694 if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0))
1698 ab->gfp_mask = gfp_mask;
1703 audit_buffer_free(ab);
1708 * audit_serial - compute a serial number for the audit record
1710 * Compute a serial number for the audit record. Audit records are
1711 * written to user-space as soon as they are generated, so a complete
1712 * audit record may be written in several pieces. The timestamp of the
1713 * record and this serial number are used by the user-space tools to
1714 * determine which pieces belong to the same audit record. The
1715 * (timestamp,serial) tuple is unique for each syscall and is live from
1716 * syscall entry to syscall exit.
1718 * NOTE: Another possibility is to store the formatted records off the
1719 * audit context (for those records that have a context), and emit them
1720 * all at syscall exit. However, this could delay the reporting of
1721 * significant errors until syscall exit (or never, if the system
1724 unsigned int audit_serial(void)
1726 static atomic_t serial = ATOMIC_INIT(0);
1728 return atomic_add_return(1, &serial);
1731 static inline void audit_get_stamp(struct audit_context *ctx,
1732 struct timespec64 *t, unsigned int *serial)
1734 if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
1735 ktime_get_coarse_real_ts64(t);
1736 *serial = audit_serial();
1741 * audit_log_start - obtain an audit buffer
1742 * @ctx: audit_context (may be NULL)
1743 * @gfp_mask: type of allocation
1744 * @type: audit message type
1746 * Returns audit_buffer pointer on success or NULL on error.
1748 * Obtain an audit buffer. This routine does locking to obtain the
1749 * audit buffer, but then no locking is required for calls to
1750 * audit_log_*format. If the task (ctx) is a task that is currently in a
1751 * syscall, then the syscall is marked as auditable and an audit record
1752 * will be written at syscall exit. If there is no associated task, then
1753 * task context (ctx) should be NULL.
1755 struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1758 struct audit_buffer *ab;
1759 struct timespec64 t;
1760 unsigned int uninitialized_var(serial);
1762 if (audit_initialized != AUDIT_INITIALIZED)
1765 if (unlikely(!audit_filter(type, AUDIT_FILTER_EXCLUDE)))
1768 /* NOTE: don't ever fail/sleep on these two conditions:
1769 * 1. auditd generated record - since we need auditd to drain the
1770 * queue; also, when we are checking for auditd, compare PIDs using
1771 * task_tgid_vnr() since auditd_pid is set in audit_receive_msg()
1772 * using a PID anchored in the caller's namespace
1773 * 2. generator holding the audit_cmd_mutex - we don't want to block
1774 * while holding the mutex */
1775 if (!(auditd_test_task(current) || audit_ctl_owner_current())) {
1776 long stime = audit_backlog_wait_time;
1778 while (audit_backlog_limit &&
1779 (skb_queue_len(&audit_queue) > audit_backlog_limit)) {
1780 /* wake kauditd to try and flush the queue */
1781 wake_up_interruptible(&kauditd_wait);
1783 /* sleep if we are allowed and we haven't exhausted our
1784 * backlog wait limit */
1785 if (gfpflags_allow_blocking(gfp_mask) && (stime > 0)) {
1786 DECLARE_WAITQUEUE(wait, current);
1788 add_wait_queue_exclusive(&audit_backlog_wait,
1790 set_current_state(TASK_UNINTERRUPTIBLE);
1791 stime = schedule_timeout(stime);
1792 remove_wait_queue(&audit_backlog_wait, &wait);
1794 if (audit_rate_check() && printk_ratelimit())
1795 pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
1796 skb_queue_len(&audit_queue),
1797 audit_backlog_limit);
1798 audit_log_lost("backlog limit exceeded");
1804 ab = audit_buffer_alloc(ctx, gfp_mask, type);
1806 audit_log_lost("out of memory in audit_log_start");
1810 audit_get_stamp(ab->ctx, &t, &serial);
1811 audit_clear_dummy(ab->ctx);
1812 audit_log_format(ab, "audit(%llu.%03lu:%u): ",
1813 (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
1819 * audit_expand - expand skb in the audit buffer
1821 * @extra: space to add at tail of the skb
1823 * Returns 0 (no space) on failed expansion, or available space if
1826 static inline int audit_expand(struct audit_buffer *ab, int extra)
1828 struct sk_buff *skb = ab->skb;
1829 int oldtail = skb_tailroom(skb);
1830 int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1831 int newtail = skb_tailroom(skb);
1834 audit_log_lost("out of memory in audit_expand");
1838 skb->truesize += newtail - oldtail;
1843 * Format an audit message into the audit buffer. If there isn't enough
1844 * room in the audit buffer, more room will be allocated and vsnprint
1845 * will be called a second time. Currently, we assume that a printk
1846 * can't format message larger than 1024 bytes, so we don't either.
1848 static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1852 struct sk_buff *skb;
1860 avail = skb_tailroom(skb);
1862 avail = audit_expand(ab, AUDIT_BUFSIZ);
1866 va_copy(args2, args);
1867 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1869 /* The printk buffer is 1024 bytes long, so if we get
1870 * here and AUDIT_BUFSIZ is at least 1024, then we can
1871 * log everything that printk could have logged. */
1872 avail = audit_expand(ab,
1873 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1876 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1887 * audit_log_format - format a message into the audit buffer.
1889 * @fmt: format string
1890 * @...: optional parameters matching @fmt string
1892 * All the work is done in audit_log_vformat.
1894 void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1900 va_start(args, fmt);
1901 audit_log_vformat(ab, fmt, args);
1906 * audit_log_n_hex - convert a buffer to hex and append it to the audit skb
1907 * @ab: the audit_buffer
1908 * @buf: buffer to convert to hex
1909 * @len: length of @buf to be converted
1911 * No return value; failure to expand is silently ignored.
1913 * This function will take the passed buf and convert it into a string of
1914 * ascii hex digits. The new string is placed onto the skb.
1916 void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
1919 int i, avail, new_len;
1921 struct sk_buff *skb;
1928 avail = skb_tailroom(skb);
1930 if (new_len >= avail) {
1931 /* Round the buffer request up to the next multiple */
1932 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1933 avail = audit_expand(ab, new_len);
1938 ptr = skb_tail_pointer(skb);
1939 for (i = 0; i < len; i++)
1940 ptr = hex_byte_pack_upper(ptr, buf[i]);
1942 skb_put(skb, len << 1); /* new string is twice the old string */
1946 * Format a string of no more than slen characters into the audit buffer,
1947 * enclosed in quote marks.
1949 void audit_log_n_string(struct audit_buffer *ab, const char *string,
1954 struct sk_buff *skb;
1961 avail = skb_tailroom(skb);
1962 new_len = slen + 3; /* enclosing quotes + null terminator */
1963 if (new_len > avail) {
1964 avail = audit_expand(ab, new_len);
1968 ptr = skb_tail_pointer(skb);
1970 memcpy(ptr, string, slen);
1974 skb_put(skb, slen + 2); /* don't include null terminator */
1978 * audit_string_contains_control - does a string need to be logged in hex
1979 * @string: string to be checked
1980 * @len: max length of the string to check
1982 bool audit_string_contains_control(const char *string, size_t len)
1984 const unsigned char *p;
1985 for (p = string; p < (const unsigned char *)string + len; p++) {
1986 if (*p == '"' || *p < 0x21 || *p > 0x7e)
1993 * audit_log_n_untrustedstring - log a string that may contain random characters
1995 * @len: length of string (not including trailing null)
1996 * @string: string to be logged
1998 * This code will escape a string that is passed to it if the string
1999 * contains a control character, unprintable character, double quote mark,
2000 * or a space. Unescaped strings will start and end with a double quote mark.
2001 * Strings that are escaped are printed in hex (2 digits per char).
2003 * The caller specifies the number of characters in the string to log, which may
2004 * or may not be the entire string.
2006 void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
2009 if (audit_string_contains_control(string, len))
2010 audit_log_n_hex(ab, string, len);
2012 audit_log_n_string(ab, string, len);
2016 * audit_log_untrustedstring - log a string that may contain random characters
2018 * @string: string to be logged
2020 * Same as audit_log_n_untrustedstring(), except that strlen is used to
2021 * determine string length.
2023 void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
2025 audit_log_n_untrustedstring(ab, string, strlen(string));
2028 /* This is a helper-function to print the escaped d_path */
2029 void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
2030 const struct path *path)
2035 audit_log_format(ab, "%s", prefix);
2037 /* We will allow 11 spaces for ' (deleted)' to be appended */
2038 pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
2040 audit_log_string(ab, "<no_memory>");
2043 p = d_path(path, pathname, PATH_MAX+11);
2044 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
2045 /* FIXME: can we save some information here? */
2046 audit_log_string(ab, "<too_long>");
2048 audit_log_untrustedstring(ab, p);
2052 void audit_log_session_info(struct audit_buffer *ab)
2054 unsigned int sessionid = audit_get_sessionid(current);
2055 uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
2057 audit_log_format(ab, "auid=%u ses=%u", auid, sessionid);
2060 void audit_log_key(struct audit_buffer *ab, char *key)
2062 audit_log_format(ab, " key=");
2064 audit_log_untrustedstring(ab, key);
2066 audit_log_format(ab, "(null)");
2069 int audit_log_task_context(struct audit_buffer *ab)
2076 security_task_getsecid(current, &sid);
2080 error = security_secid_to_secctx(sid, &ctx, &len);
2082 if (error != -EINVAL)
2087 audit_log_format(ab, " subj=%s", ctx);
2088 security_release_secctx(ctx, len);
2092 audit_panic("error in audit_log_task_context");
2095 EXPORT_SYMBOL(audit_log_task_context);
2097 void audit_log_d_path_exe(struct audit_buffer *ab,
2098 struct mm_struct *mm)
2100 struct file *exe_file;
2105 exe_file = get_mm_exe_file(mm);
2109 audit_log_d_path(ab, " exe=", &exe_file->f_path);
2113 audit_log_format(ab, " exe=(null)");
2116 struct tty_struct *audit_get_tty(void)
2118 struct tty_struct *tty = NULL;
2119 unsigned long flags;
2121 spin_lock_irqsave(¤t->sighand->siglock, flags);
2122 if (current->signal)
2123 tty = tty_kref_get(current->signal->tty);
2124 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
2128 void audit_put_tty(struct tty_struct *tty)
2133 void audit_log_task_info(struct audit_buffer *ab)
2135 const struct cred *cred;
2136 char comm[sizeof(current->comm)];
2137 struct tty_struct *tty;
2142 cred = current_cred();
2143 tty = audit_get_tty();
2144 audit_log_format(ab,
2145 " ppid=%d pid=%d auid=%u uid=%u gid=%u"
2146 " euid=%u suid=%u fsuid=%u"
2147 " egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
2148 task_ppid_nr(current),
2149 task_tgid_nr(current),
2150 from_kuid(&init_user_ns, audit_get_loginuid(current)),
2151 from_kuid(&init_user_ns, cred->uid),
2152 from_kgid(&init_user_ns, cred->gid),
2153 from_kuid(&init_user_ns, cred->euid),
2154 from_kuid(&init_user_ns, cred->suid),
2155 from_kuid(&init_user_ns, cred->fsuid),
2156 from_kgid(&init_user_ns, cred->egid),
2157 from_kgid(&init_user_ns, cred->sgid),
2158 from_kgid(&init_user_ns, cred->fsgid),
2159 tty ? tty_name(tty) : "(none)",
2160 audit_get_sessionid(current));
2162 audit_log_format(ab, " comm=");
2163 audit_log_untrustedstring(ab, get_task_comm(comm, current));
2164 audit_log_d_path_exe(ab, current->mm);
2165 audit_log_task_context(ab);
2167 EXPORT_SYMBOL(audit_log_task_info);
2170 * audit_log_path_denied - report a path restriction denial
2171 * @type: audit message type (AUDIT_ANOM_LINK, AUDIT_ANOM_CREAT, etc)
2172 * @operation: specific operation name
2174 void audit_log_path_denied(int type, const char *operation)
2176 struct audit_buffer *ab;
2178 if (!audit_enabled || audit_dummy_context())
2181 /* Generate log with subject, operation, outcome. */
2182 ab = audit_log_start(audit_context(), GFP_KERNEL, type);
2185 audit_log_format(ab, "op=%s", operation);
2186 audit_log_task_info(ab);
2187 audit_log_format(ab, " res=0");
2191 /* global counter which is incremented every time something logs in */
2192 static atomic_t session_id = ATOMIC_INIT(0);
2194 static int audit_set_loginuid_perm(kuid_t loginuid)
2196 /* if we are unset, we don't need privs */
2197 if (!audit_loginuid_set(current))
2199 /* if AUDIT_FEATURE_LOGINUID_IMMUTABLE means never ever allow a change*/
2200 if (is_audit_feature_set(AUDIT_FEATURE_LOGINUID_IMMUTABLE))
2202 /* it is set, you need permission */
2203 if (!capable(CAP_AUDIT_CONTROL))
2205 /* reject if this is not an unset and we don't allow that */
2206 if (is_audit_feature_set(AUDIT_FEATURE_ONLY_UNSET_LOGINUID)
2207 && uid_valid(loginuid))
2212 static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
2213 unsigned int oldsessionid,
2214 unsigned int sessionid, int rc)
2216 struct audit_buffer *ab;
2217 uid_t uid, oldloginuid, loginuid;
2218 struct tty_struct *tty;
2223 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_LOGIN);
2227 uid = from_kuid(&init_user_ns, task_uid(current));
2228 oldloginuid = from_kuid(&init_user_ns, koldloginuid);
2229 loginuid = from_kuid(&init_user_ns, kloginuid),
2230 tty = audit_get_tty();
2232 audit_log_format(ab, "pid=%d uid=%u", task_tgid_nr(current), uid);
2233 audit_log_task_context(ab);
2234 audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",
2235 oldloginuid, loginuid, tty ? tty_name(tty) : "(none)",
2236 oldsessionid, sessionid, !rc);
2242 * audit_set_loginuid - set current task's loginuid
2243 * @loginuid: loginuid value
2247 * Called (set) from fs/proc/base.c::proc_loginuid_write().
2249 int audit_set_loginuid(kuid_t loginuid)
2251 unsigned int oldsessionid, sessionid = AUDIT_SID_UNSET;
2255 oldloginuid = audit_get_loginuid(current);
2256 oldsessionid = audit_get_sessionid(current);
2258 rc = audit_set_loginuid_perm(loginuid);
2262 /* are we setting or clearing? */
2263 if (uid_valid(loginuid)) {
2264 sessionid = (unsigned int)atomic_inc_return(&session_id);
2265 if (unlikely(sessionid == AUDIT_SID_UNSET))
2266 sessionid = (unsigned int)atomic_inc_return(&session_id);
2269 current->sessionid = sessionid;
2270 current->loginuid = loginuid;
2272 audit_log_set_loginuid(oldloginuid, loginuid, oldsessionid, sessionid, rc);
2277 * audit_signal_info - record signal info for shutting down audit subsystem
2278 * @sig: signal value
2279 * @t: task being signaled
2281 * If the audit subsystem is being terminated, record the task (pid)
2282 * and uid that is doing that.
2284 int audit_signal_info(int sig, struct task_struct *t)
2286 kuid_t uid = current_uid(), auid;
2288 if (auditd_test_task(t) &&
2289 (sig == SIGTERM || sig == SIGHUP ||
2290 sig == SIGUSR1 || sig == SIGUSR2)) {
2291 audit_sig_pid = task_tgid_nr(current);
2292 auid = audit_get_loginuid(current);
2293 if (uid_valid(auid))
2294 audit_sig_uid = auid;
2296 audit_sig_uid = uid;
2297 security_task_getsecid(current, &audit_sig_sid);
2300 return audit_signal_info_syscall(t);
2304 * audit_log_end - end one audit record
2305 * @ab: the audit_buffer
2307 * We can not do a netlink send inside an irq context because it blocks (last
2308 * arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a
2309 * queue and a tasklet is scheduled to remove them from the queue outside the
2310 * irq context. May be called in any context.
2312 void audit_log_end(struct audit_buffer *ab)
2314 struct sk_buff *skb;
2315 struct nlmsghdr *nlh;
2320 if (audit_rate_check()) {
2324 /* setup the netlink header, see the comments in
2325 * kauditd_send_multicast_skb() for length quirks */
2326 nlh = nlmsg_hdr(skb);
2327 nlh->nlmsg_len = skb->len - NLMSG_HDRLEN;
2329 /* queue the netlink packet and poke the kauditd thread */
2330 skb_queue_tail(&audit_queue, skb);
2331 wake_up_interruptible(&kauditd_wait);
2333 audit_log_lost("rate limit exceeded");
2335 audit_buffer_free(ab);
2339 * audit_log - Log an audit record
2340 * @ctx: audit context
2341 * @gfp_mask: type of allocation
2342 * @type: audit message type
2343 * @fmt: format string to use
2344 * @...: variable parameters matching the format string
2346 * This is a convenience function that calls audit_log_start,
2347 * audit_log_vformat, and audit_log_end. It may be called
2350 void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
2351 const char *fmt, ...)
2353 struct audit_buffer *ab;
2356 ab = audit_log_start(ctx, gfp_mask, type);
2358 va_start(args, fmt);
2359 audit_log_vformat(ab, fmt, args);
2365 EXPORT_SYMBOL(audit_log_start);
2366 EXPORT_SYMBOL(audit_log_end);
2367 EXPORT_SYMBOL(audit_log_format);
2368 EXPORT_SYMBOL(audit_log);