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 2003-2004 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 SELinux.
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 #include <linux/init.h>
45 #include <asm/types.h>
46 #include <asm/atomic.h>
48 #include <linux/module.h>
49 #include <linux/err.h>
50 #include <linux/kthread.h>
52 #include <linux/audit.h>
55 #include <net/netlink.h>
56 #include <linux/skbuff.h>
57 #include <linux/netlink.h>
58 #include <linux/selinux.h>
62 /* No auditing will take place until audit_initialized != 0.
63 * (Initialization happens after skb_init is called.) */
64 static int audit_initialized;
66 /* No syscall auditing will take place unless audit_enabled != 0. */
69 /* Default state when kernel boots without any parameters. */
70 static int audit_default;
72 /* If auditing cannot proceed, audit_failure selects what happens. */
73 static int audit_failure = AUDIT_FAIL_PRINTK;
75 /* If audit records are to be written to the netlink socket, audit_pid
76 * contains the (non-zero) pid. */
79 /* If audit_rate_limit is non-zero, limit the rate of sending audit records
80 * to that number per second. This prevents DoS attacks, but results in
81 * audit records being dropped. */
82 static int audit_rate_limit;
84 /* Number of outstanding audit_buffers allowed. */
85 static int audit_backlog_limit = 64;
86 static int audit_backlog_wait_time = 60 * HZ;
87 static int audit_backlog_wait_overflow = 0;
89 /* The identity of the user shutting down the audit system. */
90 uid_t audit_sig_uid = -1;
91 pid_t audit_sig_pid = -1;
93 /* Records can be lost in several ways:
94 0) [suppressed in audit_alloc]
95 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
96 2) out of memory in audit_log_move [alloc_skb]
97 3) suppressed due to audit_rate_limit
98 4) suppressed due to audit_backlog_limit
100 static atomic_t audit_lost = ATOMIC_INIT(0);
102 /* The netlink socket. */
103 static struct sock *audit_sock;
105 /* The audit_freelist is a list of pre-allocated audit buffers (if more
106 * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
107 * being placed on the freelist). */
108 static DEFINE_SPINLOCK(audit_freelist_lock);
109 static int audit_freelist_count;
110 static LIST_HEAD(audit_freelist);
112 static struct sk_buff_head audit_skb_queue;
113 static struct task_struct *kauditd_task;
114 static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
115 static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
117 /* The netlink socket is only to be read by 1 CPU, which lets us assume
118 * that list additions and deletions never happen simultaneously in
120 DEFINE_MUTEX(audit_netlink_mutex);
122 /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
123 * audit records. Since printk uses a 1024 byte buffer, this buffer
124 * should be at least that large. */
125 #define AUDIT_BUFSIZ 1024
127 /* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the
128 * audit_freelist. Doing so eliminates many kmalloc/kfree calls. */
129 #define AUDIT_MAXFREE (2*NR_CPUS)
131 /* The audit_buffer is used when formatting an audit record. The caller
132 * locks briefly to get the record off the freelist or to allocate the
133 * buffer, and locks briefly to send the buffer to the netlink layer or
134 * to place it on a transmit queue. Multiple audit_buffers can be in
135 * use simultaneously. */
136 struct audit_buffer {
137 struct list_head list;
138 struct sk_buff *skb; /* formatted skb ready to send */
139 struct audit_context *ctx; /* NULL or associated context */
143 static void audit_set_pid(struct audit_buffer *ab, pid_t pid)
145 struct nlmsghdr *nlh = (struct nlmsghdr *)ab->skb->data;
146 nlh->nlmsg_pid = pid;
149 void audit_panic(const char *message)
151 switch (audit_failure)
153 case AUDIT_FAIL_SILENT:
155 case AUDIT_FAIL_PRINTK:
156 printk(KERN_ERR "audit: %s\n", message);
158 case AUDIT_FAIL_PANIC:
159 panic("audit: %s\n", message);
164 static inline int audit_rate_check(void)
166 static unsigned long last_check = 0;
167 static int messages = 0;
168 static DEFINE_SPINLOCK(lock);
171 unsigned long elapsed;
174 if (!audit_rate_limit) return 1;
176 spin_lock_irqsave(&lock, flags);
177 if (++messages < audit_rate_limit) {
181 elapsed = now - last_check;
188 spin_unlock_irqrestore(&lock, flags);
194 * audit_log_lost - conditionally log lost audit message event
195 * @message: the message stating reason for lost audit message
197 * Emit at least 1 message per second, even if audit_rate_check is
199 * Always increment the lost messages counter.
201 void audit_log_lost(const char *message)
203 static unsigned long last_msg = 0;
204 static DEFINE_SPINLOCK(lock);
209 atomic_inc(&audit_lost);
211 print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
214 spin_lock_irqsave(&lock, flags);
216 if (now - last_msg > HZ) {
220 spin_unlock_irqrestore(&lock, flags);
225 "audit: audit_lost=%d audit_rate_limit=%d audit_backlog_limit=%d\n",
226 atomic_read(&audit_lost),
228 audit_backlog_limit);
229 audit_panic(message);
233 static int audit_set_rate_limit(int limit, uid_t loginuid, u32 sid)
235 int old = audit_rate_limit;
241 if ((rc = selinux_ctxid_to_string(sid, &ctx, &len)))
244 audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
245 "audit_rate_limit=%d old=%d by auid=%u subj=%s",
246 limit, old, loginuid, ctx);
249 audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
250 "audit_rate_limit=%d old=%d by auid=%u",
251 limit, old, loginuid);
252 audit_rate_limit = limit;
256 static int audit_set_backlog_limit(int limit, uid_t loginuid, u32 sid)
258 int old = audit_backlog_limit;
264 if ((rc = selinux_ctxid_to_string(sid, &ctx, &len)))
267 audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
268 "audit_backlog_limit=%d old=%d by auid=%u subj=%s",
269 limit, old, loginuid, ctx);
272 audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
273 "audit_backlog_limit=%d old=%d by auid=%u",
274 limit, old, loginuid);
275 audit_backlog_limit = limit;
279 static int audit_set_enabled(int state, uid_t loginuid, u32 sid)
281 int old = audit_enabled;
283 if (state != 0 && state != 1)
290 if ((rc = selinux_ctxid_to_string(sid, &ctx, &len)))
293 audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
294 "audit_enabled=%d old=%d by auid=%u subj=%s",
295 state, old, loginuid, ctx);
298 audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
299 "audit_enabled=%d old=%d by auid=%u",
300 state, old, loginuid);
301 audit_enabled = state;
305 static int audit_set_failure(int state, uid_t loginuid, u32 sid)
307 int old = audit_failure;
309 if (state != AUDIT_FAIL_SILENT
310 && state != AUDIT_FAIL_PRINTK
311 && state != AUDIT_FAIL_PANIC)
318 if ((rc = selinux_ctxid_to_string(sid, &ctx, &len)))
321 audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
322 "audit_failure=%d old=%d by auid=%u subj=%s",
323 state, old, loginuid, ctx);
326 audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
327 "audit_failure=%d old=%d by auid=%u",
328 state, old, loginuid);
329 audit_failure = state;
333 static int kauditd_thread(void *dummy)
338 skb = skb_dequeue(&audit_skb_queue);
339 wake_up(&audit_backlog_wait);
342 int err = netlink_unicast(audit_sock, skb, audit_pid, 0);
344 BUG_ON(err != -ECONNREFUSED); /* Shoudn't happen */
345 printk(KERN_ERR "audit: *NO* daemon at audit_pid=%d\n", audit_pid);
349 printk(KERN_NOTICE "%s\n", skb->data + NLMSG_SPACE(0));
353 DECLARE_WAITQUEUE(wait, current);
354 set_current_state(TASK_INTERRUPTIBLE);
355 add_wait_queue(&kauditd_wait, &wait);
357 if (!skb_queue_len(&audit_skb_queue)) {
362 __set_current_state(TASK_RUNNING);
363 remove_wait_queue(&kauditd_wait, &wait);
369 int audit_send_list(void *_dest)
371 struct audit_netlink_list *dest = _dest;
375 /* wait for parent to finish and send an ACK */
376 mutex_lock(&audit_netlink_mutex);
377 mutex_unlock(&audit_netlink_mutex);
379 while ((skb = __skb_dequeue(&dest->q)) != NULL)
380 netlink_unicast(audit_sock, skb, pid, 0);
387 struct sk_buff *audit_make_reply(int pid, int seq, int type, int done,
388 int multi, void *payload, int size)
391 struct nlmsghdr *nlh;
392 int len = NLMSG_SPACE(size);
394 int flags = multi ? NLM_F_MULTI : 0;
395 int t = done ? NLMSG_DONE : type;
397 skb = alloc_skb(len, GFP_KERNEL);
401 nlh = NLMSG_PUT(skb, pid, seq, t, size);
402 nlh->nlmsg_flags = flags;
403 data = NLMSG_DATA(nlh);
404 memcpy(data, payload, size);
407 nlmsg_failure: /* Used by NLMSG_PUT */
414 * audit_send_reply - send an audit reply message via netlink
415 * @pid: process id to send reply to
416 * @seq: sequence number
417 * @type: audit message type
418 * @done: done (last) flag
419 * @multi: multi-part message flag
420 * @payload: payload data
421 * @size: payload size
423 * Allocates an skb, builds the netlink message, and sends it to the pid.
424 * No failure notifications.
426 void audit_send_reply(int pid, int seq, int type, int done, int multi,
427 void *payload, int size)
430 skb = audit_make_reply(pid, seq, type, done, multi, payload, size);
433 /* Ignore failure. It'll only happen if the sender goes away,
434 because our timeout is set to infinite. */
435 netlink_unicast(audit_sock, skb, pid, 0);
440 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
443 static int audit_netlink_ok(kernel_cap_t eff_cap, u16 msg_type)
450 case AUDIT_LIST_RULES:
456 case AUDIT_SIGNAL_INFO:
457 if (!cap_raised(eff_cap, CAP_AUDIT_CONTROL))
461 case AUDIT_FIRST_USER_MSG...AUDIT_LAST_USER_MSG:
462 case AUDIT_FIRST_USER_MSG2...AUDIT_LAST_USER_MSG2:
463 if (!cap_raised(eff_cap, CAP_AUDIT_WRITE))
466 default: /* bad msg */
473 static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
475 u32 uid, pid, seq, sid;
477 struct audit_status *status_get, status_set;
479 struct audit_buffer *ab;
480 u16 msg_type = nlh->nlmsg_type;
481 uid_t loginuid; /* loginuid of sender */
482 struct audit_sig_info sig_data;
484 err = audit_netlink_ok(NETLINK_CB(skb).eff_cap, msg_type);
488 /* As soon as there's any sign of userspace auditd,
489 * start kauditd to talk to it */
491 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
492 if (IS_ERR(kauditd_task)) {
493 err = PTR_ERR(kauditd_task);
498 pid = NETLINK_CREDS(skb)->pid;
499 uid = NETLINK_CREDS(skb)->uid;
500 loginuid = NETLINK_CB(skb).loginuid;
501 sid = NETLINK_CB(skb).sid;
502 seq = nlh->nlmsg_seq;
503 data = NLMSG_DATA(nlh);
507 status_set.enabled = audit_enabled;
508 status_set.failure = audit_failure;
509 status_set.pid = audit_pid;
510 status_set.rate_limit = audit_rate_limit;
511 status_set.backlog_limit = audit_backlog_limit;
512 status_set.lost = atomic_read(&audit_lost);
513 status_set.backlog = skb_queue_len(&audit_skb_queue);
514 audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_GET, 0, 0,
515 &status_set, sizeof(status_set));
518 if (nlh->nlmsg_len < sizeof(struct audit_status))
520 status_get = (struct audit_status *)data;
521 if (status_get->mask & AUDIT_STATUS_ENABLED) {
522 err = audit_set_enabled(status_get->enabled,
524 if (err < 0) return err;
526 if (status_get->mask & AUDIT_STATUS_FAILURE) {
527 err = audit_set_failure(status_get->failure,
529 if (err < 0) return err;
531 if (status_get->mask & AUDIT_STATUS_PID) {
537 if ((rc = selinux_ctxid_to_string(
541 audit_log(NULL, GFP_KERNEL,
543 "audit_pid=%d old=%d by auid=%u subj=%s",
544 status_get->pid, old,
548 audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
549 "audit_pid=%d old=%d by auid=%u",
550 status_get->pid, old, loginuid);
551 audit_pid = status_get->pid;
553 if (status_get->mask & AUDIT_STATUS_RATE_LIMIT)
554 audit_set_rate_limit(status_get->rate_limit,
556 if (status_get->mask & AUDIT_STATUS_BACKLOG_LIMIT)
557 audit_set_backlog_limit(status_get->backlog_limit,
561 case AUDIT_FIRST_USER_MSG...AUDIT_LAST_USER_MSG:
562 case AUDIT_FIRST_USER_MSG2...AUDIT_LAST_USER_MSG2:
563 if (!audit_enabled && msg_type != AUDIT_USER_AVC)
566 err = audit_filter_user(&NETLINK_CB(skb), msg_type);
569 ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
572 "user pid=%d uid=%u auid=%u",
577 if (selinux_ctxid_to_string(
581 /* Maybe call audit_panic? */
587 audit_log_format(ab, " msg='%.1024s'",
589 audit_set_pid(ab, pid);
596 if (nlmsg_len(nlh) < sizeof(struct audit_rule))
600 err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid,
601 uid, seq, data, nlmsg_len(nlh),
606 if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
609 case AUDIT_LIST_RULES:
610 err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid,
611 uid, seq, data, nlmsg_len(nlh),
614 case AUDIT_SIGNAL_INFO:
615 sig_data.uid = audit_sig_uid;
616 sig_data.pid = audit_sig_pid;
617 audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_SIGNAL_INFO,
618 0, 0, &sig_data, sizeof(sig_data));
625 return err < 0 ? err : 0;
629 * Get message from skb (based on rtnetlink_rcv_skb). Each message is
630 * processed by audit_receive_msg. Malformed skbs with wrong length are
631 * discarded silently.
633 static void audit_receive_skb(struct sk_buff *skb)
636 struct nlmsghdr *nlh;
639 while (skb->len >= NLMSG_SPACE(0)) {
640 nlh = (struct nlmsghdr *)skb->data;
641 if (nlh->nlmsg_len < sizeof(*nlh) || skb->len < nlh->nlmsg_len)
643 rlen = NLMSG_ALIGN(nlh->nlmsg_len);
646 if ((err = audit_receive_msg(skb, nlh))) {
647 netlink_ack(skb, nlh, err);
648 } else if (nlh->nlmsg_flags & NLM_F_ACK)
649 netlink_ack(skb, nlh, 0);
654 /* Receive messages from netlink socket. */
655 static void audit_receive(struct sock *sk, int length)
660 mutex_lock(&audit_netlink_mutex);
662 for (qlen = skb_queue_len(&sk->sk_receive_queue); qlen; qlen--) {
663 skb = skb_dequeue(&sk->sk_receive_queue);
664 audit_receive_skb(skb);
667 mutex_unlock(&audit_netlink_mutex);
671 /* Initialize audit support at boot time. */
672 static int __init audit_init(void)
674 printk(KERN_INFO "audit: initializing netlink socket (%s)\n",
675 audit_default ? "enabled" : "disabled");
676 audit_sock = netlink_kernel_create(NETLINK_AUDIT, 0, audit_receive,
679 audit_panic("cannot initialize netlink socket");
681 audit_sock->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
683 skb_queue_head_init(&audit_skb_queue);
684 audit_initialized = 1;
685 audit_enabled = audit_default;
687 /* Register the callback with selinux. This callback will be invoked
688 * when a new policy is loaded. */
689 selinux_audit_set_callback(&selinux_audit_rule_update);
691 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized");
694 __initcall(audit_init);
696 /* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
697 static int __init audit_enable(char *str)
699 audit_default = !!simple_strtol(str, NULL, 0);
700 printk(KERN_INFO "audit: %s%s\n",
701 audit_default ? "enabled" : "disabled",
702 audit_initialized ? "" : " (after initialization)");
703 if (audit_initialized)
704 audit_enabled = audit_default;
708 __setup("audit=", audit_enable);
710 static void audit_buffer_free(struct audit_buffer *ab)
720 spin_lock_irqsave(&audit_freelist_lock, flags);
721 if (++audit_freelist_count > AUDIT_MAXFREE)
724 list_add(&ab->list, &audit_freelist);
725 spin_unlock_irqrestore(&audit_freelist_lock, flags);
728 static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx,
729 gfp_t gfp_mask, int type)
732 struct audit_buffer *ab = NULL;
733 struct nlmsghdr *nlh;
735 spin_lock_irqsave(&audit_freelist_lock, flags);
736 if (!list_empty(&audit_freelist)) {
737 ab = list_entry(audit_freelist.next,
738 struct audit_buffer, list);
740 --audit_freelist_count;
742 spin_unlock_irqrestore(&audit_freelist_lock, flags);
745 ab = kmalloc(sizeof(*ab), gfp_mask);
750 ab->skb = alloc_skb(AUDIT_BUFSIZ, gfp_mask);
755 ab->gfp_mask = gfp_mask;
756 nlh = (struct nlmsghdr *)skb_put(ab->skb, NLMSG_SPACE(0));
757 nlh->nlmsg_type = type;
758 nlh->nlmsg_flags = 0;
763 audit_buffer_free(ab);
768 * audit_serial - compute a serial number for the audit record
770 * Compute a serial number for the audit record. Audit records are
771 * written to user-space as soon as they are generated, so a complete
772 * audit record may be written in several pieces. The timestamp of the
773 * record and this serial number are used by the user-space tools to
774 * determine which pieces belong to the same audit record. The
775 * (timestamp,serial) tuple is unique for each syscall and is live from
776 * syscall entry to syscall exit.
778 * NOTE: Another possibility is to store the formatted records off the
779 * audit context (for those records that have a context), and emit them
780 * all at syscall exit. However, this could delay the reporting of
781 * significant errors until syscall exit (or never, if the system
784 unsigned int audit_serial(void)
786 static spinlock_t serial_lock = SPIN_LOCK_UNLOCKED;
787 static unsigned int serial = 0;
792 spin_lock_irqsave(&serial_lock, flags);
795 } while (unlikely(!ret));
796 spin_unlock_irqrestore(&serial_lock, flags);
801 static inline void audit_get_stamp(struct audit_context *ctx,
802 struct timespec *t, unsigned int *serial)
805 auditsc_get_stamp(ctx, t, serial);
808 *serial = audit_serial();
812 /* Obtain an audit buffer. This routine does locking to obtain the
813 * audit buffer, but then no locking is required for calls to
814 * audit_log_*format. If the tsk is a task that is currently in a
815 * syscall, then the syscall is marked as auditable and an audit record
816 * will be written at syscall exit. If there is no associated task, tsk
820 * audit_log_start - obtain an audit buffer
821 * @ctx: audit_context (may be NULL)
822 * @gfp_mask: type of allocation
823 * @type: audit message type
825 * Returns audit_buffer pointer on success or NULL on error.
827 * Obtain an audit buffer. This routine does locking to obtain the
828 * audit buffer, but then no locking is required for calls to
829 * audit_log_*format. If the task (ctx) is a task that is currently in a
830 * syscall, then the syscall is marked as auditable and an audit record
831 * will be written at syscall exit. If there is no associated task, then
832 * task context (ctx) should be NULL.
834 struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
837 struct audit_buffer *ab = NULL;
841 unsigned long timeout_start = jiffies;
843 if (!audit_initialized)
846 if (unlikely(audit_filter_type(type)))
849 if (gfp_mask & __GFP_WAIT)
852 reserve = 5; /* Allow atomic callers to go up to five
853 entries over the normal backlog limit */
855 while (audit_backlog_limit
856 && skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) {
857 if (gfp_mask & __GFP_WAIT && audit_backlog_wait_time
858 && time_before(jiffies, timeout_start + audit_backlog_wait_time)) {
860 /* Wait for auditd to drain the queue a little */
861 DECLARE_WAITQUEUE(wait, current);
862 set_current_state(TASK_INTERRUPTIBLE);
863 add_wait_queue(&audit_backlog_wait, &wait);
865 if (audit_backlog_limit &&
866 skb_queue_len(&audit_skb_queue) > audit_backlog_limit)
867 schedule_timeout(timeout_start + audit_backlog_wait_time - jiffies);
869 __set_current_state(TASK_RUNNING);
870 remove_wait_queue(&audit_backlog_wait, &wait);
873 if (audit_rate_check())
875 "audit: audit_backlog=%d > "
876 "audit_backlog_limit=%d\n",
877 skb_queue_len(&audit_skb_queue),
878 audit_backlog_limit);
879 audit_log_lost("backlog limit exceeded");
880 audit_backlog_wait_time = audit_backlog_wait_overflow;
881 wake_up(&audit_backlog_wait);
885 ab = audit_buffer_alloc(ctx, gfp_mask, type);
887 audit_log_lost("out of memory in audit_log_start");
891 audit_get_stamp(ab->ctx, &t, &serial);
893 audit_log_format(ab, "audit(%lu.%03lu:%u): ",
894 t.tv_sec, t.tv_nsec/1000000, serial);
899 * audit_expand - expand skb in the audit buffer
901 * @extra: space to add at tail of the skb
903 * Returns 0 (no space) on failed expansion, or available space if
906 static inline int audit_expand(struct audit_buffer *ab, int extra)
908 struct sk_buff *skb = ab->skb;
909 int ret = pskb_expand_head(skb, skb_headroom(skb), extra,
912 audit_log_lost("out of memory in audit_expand");
915 return skb_tailroom(skb);
919 * Format an audit message into the audit buffer. If there isn't enough
920 * room in the audit buffer, more room will be allocated and vsnprint
921 * will be called a second time. Currently, we assume that a printk
922 * can't format message larger than 1024 bytes, so we don't either.
924 static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
936 avail = skb_tailroom(skb);
938 avail = audit_expand(ab, AUDIT_BUFSIZ);
942 va_copy(args2, args);
943 len = vsnprintf(skb->tail, avail, fmt, args);
945 /* The printk buffer is 1024 bytes long, so if we get
946 * here and AUDIT_BUFSIZ is at least 1024, then we can
947 * log everything that printk could have logged. */
948 avail = audit_expand(ab,
949 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
952 len = vsnprintf(skb->tail, avail, fmt, args2);
961 * audit_log_format - format a message into the audit buffer.
963 * @fmt: format string
964 * @...: optional parameters matching @fmt string
966 * All the work is done in audit_log_vformat.
968 void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
975 audit_log_vformat(ab, fmt, args);
980 * audit_log_hex - convert a buffer to hex and append it to the audit skb
981 * @ab: the audit_buffer
982 * @buf: buffer to convert to hex
983 * @len: length of @buf to be converted
985 * No return value; failure to expand is silently ignored.
987 * This function will take the passed buf and convert it into a string of
988 * ascii hex digits. The new string is placed onto the skb.
990 void audit_log_hex(struct audit_buffer *ab, const unsigned char *buf,
993 int i, avail, new_len;
996 static const unsigned char *hex = "0123456789ABCDEF";
1000 avail = skb_tailroom(skb);
1002 if (new_len >= avail) {
1003 /* Round the buffer request up to the next multiple */
1004 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1005 avail = audit_expand(ab, new_len);
1011 for (i=0; i<len; i++) {
1012 *ptr++ = hex[(buf[i] & 0xF0)>>4]; /* Upper nibble */
1013 *ptr++ = hex[buf[i] & 0x0F]; /* Lower nibble */
1016 skb_put(skb, len << 1); /* new string is twice the old string */
1020 * audit_log_unstrustedstring - log a string that may contain random characters
1022 * @string: string to be logged
1024 * This code will escape a string that is passed to it if the string
1025 * contains a control character, unprintable character, double quote mark,
1026 * or a space. Unescaped strings will start and end with a double quote mark.
1027 * Strings that are escaped are printed in hex (2 digits per char).
1029 const char *audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
1031 const unsigned char *p = string;
1032 size_t len = strlen(string);
1035 if (*p == '"' || *p < 0x21 || *p > 0x7f) {
1036 audit_log_hex(ab, string, len);
1037 return string + len + 1;
1041 audit_log_format(ab, "\"%s\"", string);
1045 /* This is a helper-function to print the escaped d_path */
1046 void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
1047 struct dentry *dentry, struct vfsmount *vfsmnt)
1052 audit_log_format(ab, " %s", prefix);
1054 /* We will allow 11 spaces for ' (deleted)' to be appended */
1055 path = kmalloc(PATH_MAX+11, ab->gfp_mask);
1057 audit_log_format(ab, "<no memory>");
1060 p = d_path(dentry, vfsmnt, path, PATH_MAX+11);
1061 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
1062 /* FIXME: can we save some information here? */
1063 audit_log_format(ab, "<too long>");
1065 audit_log_untrustedstring(ab, p);
1070 * audit_log_end - end one audit record
1071 * @ab: the audit_buffer
1073 * The netlink_* functions cannot be called inside an irq context, so
1074 * the audit buffer is placed on a queue and a tasklet is scheduled to
1075 * remove them from the queue outside the irq context. May be called in
1078 void audit_log_end(struct audit_buffer *ab)
1082 if (!audit_rate_check()) {
1083 audit_log_lost("rate limit exceeded");
1086 struct nlmsghdr *nlh = (struct nlmsghdr *)ab->skb->data;
1087 nlh->nlmsg_len = ab->skb->len - NLMSG_SPACE(0);
1088 skb_queue_tail(&audit_skb_queue, ab->skb);
1090 wake_up_interruptible(&kauditd_wait);
1092 printk(KERN_NOTICE "%s\n", ab->skb->data + NLMSG_SPACE(0));
1095 audit_buffer_free(ab);
1099 * audit_log - Log an audit record
1100 * @ctx: audit context
1101 * @gfp_mask: type of allocation
1102 * @type: audit message type
1103 * @fmt: format string to use
1104 * @...: variable parameters matching the format string
1106 * This is a convenience function that calls audit_log_start,
1107 * audit_log_vformat, and audit_log_end. It may be called
1110 void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
1111 const char *fmt, ...)
1113 struct audit_buffer *ab;
1116 ab = audit_log_start(ctx, gfp_mask, type);
1118 va_start(args, fmt);
1119 audit_log_vformat(ab, fmt, args);
1125 EXPORT_SYMBOL(audit_log_start);
1126 EXPORT_SYMBOL(audit_log_end);
1127 EXPORT_SYMBOL(audit_log_format);
1128 EXPORT_SYMBOL(audit_log);