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 <linux/skbuff.h>
56 #include <linux/netlink.h>
58 /* No auditing will take place until audit_initialized != 0.
59 * (Initialization happens after skb_init is called.) */
60 static int audit_initialized
;
62 /* No syscall auditing will take place unless audit_enabled != 0. */
65 /* Default state when kernel boots without any parameters. */
66 static int audit_default
;
68 /* If auditing cannot proceed, audit_failure selects what happens. */
69 static int audit_failure
= AUDIT_FAIL_PRINTK
;
71 /* If audit records are to be written to the netlink socket, audit_pid
72 * contains the (non-zero) pid. */
75 /* If audit_rate_limit is non-zero, limit the rate of sending audit records
76 * to that number per second. This prevents DoS attacks, but results in
77 * audit records being dropped. */
78 static int audit_rate_limit
;
80 /* Number of outstanding audit_buffers allowed. */
81 static int audit_backlog_limit
= 64;
82 static int audit_backlog_wait_time
= 60 * HZ
;
83 static int audit_backlog_wait_overflow
= 0;
85 /* The identity of the user shutting down the audit system. */
86 uid_t audit_sig_uid
= -1;
87 pid_t audit_sig_pid
= -1;
89 /* Records can be lost in several ways:
90 0) [suppressed in audit_alloc]
91 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
92 2) out of memory in audit_log_move [alloc_skb]
93 3) suppressed due to audit_rate_limit
94 4) suppressed due to audit_backlog_limit
96 static atomic_t audit_lost
= ATOMIC_INIT(0);
98 /* The netlink socket. */
99 static struct sock
*audit_sock
;
101 /* The audit_freelist is a list of pre-allocated audit buffers (if more
102 * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
103 * being placed on the freelist). */
104 static DEFINE_SPINLOCK(audit_freelist_lock
);
105 static int audit_freelist_count
;
106 static LIST_HEAD(audit_freelist
);
108 static struct sk_buff_head audit_skb_queue
;
109 static struct task_struct
*kauditd_task
;
110 static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait
);
111 static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait
);
113 /* The netlink socket is only to be read by 1 CPU, which lets us assume
114 * that list additions and deletions never happen simultaneously in
116 DECLARE_MUTEX(audit_netlink_sem
);
118 /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
119 * audit records. Since printk uses a 1024 byte buffer, this buffer
120 * should be at least that large. */
121 #define AUDIT_BUFSIZ 1024
123 /* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the
124 * audit_freelist. Doing so eliminates many kmalloc/kfree calls. */
125 #define AUDIT_MAXFREE (2*NR_CPUS)
127 /* The audit_buffer is used when formatting an audit record. The caller
128 * locks briefly to get the record off the freelist or to allocate the
129 * buffer, and locks briefly to send the buffer to the netlink layer or
130 * to place it on a transmit queue. Multiple audit_buffers can be in
131 * use simultaneously. */
132 struct audit_buffer
{
133 struct list_head list
;
134 struct sk_buff
*skb
; /* formatted skb ready to send */
135 struct audit_context
*ctx
; /* NULL or associated context */
139 static void audit_set_pid(struct audit_buffer
*ab
, pid_t pid
)
141 struct nlmsghdr
*nlh
= (struct nlmsghdr
*)ab
->skb
->data
;
142 nlh
->nlmsg_pid
= pid
;
145 static void audit_panic(const char *message
)
147 switch (audit_failure
)
149 case AUDIT_FAIL_SILENT
:
151 case AUDIT_FAIL_PRINTK
:
152 printk(KERN_ERR
"audit: %s\n", message
);
154 case AUDIT_FAIL_PANIC
:
155 panic("audit: %s\n", message
);
160 static inline int audit_rate_check(void)
162 static unsigned long last_check
= 0;
163 static int messages
= 0;
164 static DEFINE_SPINLOCK(lock
);
167 unsigned long elapsed
;
170 if (!audit_rate_limit
) return 1;
172 spin_lock_irqsave(&lock
, flags
);
173 if (++messages
< audit_rate_limit
) {
177 elapsed
= now
- last_check
;
184 spin_unlock_irqrestore(&lock
, flags
);
190 * audit_log_lost - conditionally log lost audit message event
191 * @message: the message stating reason for lost audit message
193 * Emit at least 1 message per second, even if audit_rate_check is
195 * Always increment the lost messages counter.
197 void audit_log_lost(const char *message
)
199 static unsigned long last_msg
= 0;
200 static DEFINE_SPINLOCK(lock
);
205 atomic_inc(&audit_lost
);
207 print
= (audit_failure
== AUDIT_FAIL_PANIC
|| !audit_rate_limit
);
210 spin_lock_irqsave(&lock
, flags
);
212 if (now
- last_msg
> HZ
) {
216 spin_unlock_irqrestore(&lock
, flags
);
221 "audit: audit_lost=%d audit_rate_limit=%d audit_backlog_limit=%d\n",
222 atomic_read(&audit_lost
),
224 audit_backlog_limit
);
225 audit_panic(message
);
229 static int audit_set_rate_limit(int limit
, uid_t loginuid
)
231 int old
= audit_rate_limit
;
232 audit_rate_limit
= limit
;
233 audit_log(NULL
, GFP_KERNEL
, AUDIT_CONFIG_CHANGE
,
234 "audit_rate_limit=%d old=%d by auid=%u",
235 audit_rate_limit
, old
, loginuid
);
239 static int audit_set_backlog_limit(int limit
, uid_t loginuid
)
241 int old
= audit_backlog_limit
;
242 audit_backlog_limit
= limit
;
243 audit_log(NULL
, GFP_KERNEL
, AUDIT_CONFIG_CHANGE
,
244 "audit_backlog_limit=%d old=%d by auid=%u",
245 audit_backlog_limit
, old
, loginuid
);
249 static int audit_set_enabled(int state
, uid_t loginuid
)
251 int old
= audit_enabled
;
252 if (state
!= 0 && state
!= 1)
254 audit_enabled
= state
;
255 audit_log(NULL
, GFP_KERNEL
, AUDIT_CONFIG_CHANGE
,
256 "audit_enabled=%d old=%d by auid=%u",
257 audit_enabled
, old
, loginuid
);
261 static int audit_set_failure(int state
, uid_t loginuid
)
263 int old
= audit_failure
;
264 if (state
!= AUDIT_FAIL_SILENT
265 && state
!= AUDIT_FAIL_PRINTK
266 && state
!= AUDIT_FAIL_PANIC
)
268 audit_failure
= state
;
269 audit_log(NULL
, GFP_KERNEL
, AUDIT_CONFIG_CHANGE
,
270 "audit_failure=%d old=%d by auid=%u",
271 audit_failure
, old
, loginuid
);
275 static int kauditd_thread(void *dummy
)
280 skb
= skb_dequeue(&audit_skb_queue
);
281 wake_up(&audit_backlog_wait
);
284 int err
= netlink_unicast(audit_sock
, skb
, audit_pid
, 0);
286 BUG_ON(err
!= -ECONNREFUSED
); /* Shoudn't happen */
287 printk(KERN_ERR
"audit: *NO* daemon at audit_pid=%d\n", audit_pid
);
291 printk(KERN_NOTICE
"%s\n", skb
->data
+ NLMSG_SPACE(0));
295 DECLARE_WAITQUEUE(wait
, current
);
296 set_current_state(TASK_INTERRUPTIBLE
);
297 add_wait_queue(&kauditd_wait
, &wait
);
299 if (!skb_queue_len(&audit_skb_queue
)) {
304 __set_current_state(TASK_RUNNING
);
305 remove_wait_queue(&kauditd_wait
, &wait
);
311 * audit_send_reply - send an audit reply message via netlink
312 * @pid: process id to send reply to
313 * @seq: sequence number
314 * @type: audit message type
315 * @done: done (last) flag
316 * @multi: multi-part message flag
317 * @payload: payload data
318 * @size: payload size
320 * Allocates an skb, builds the netlink message, and sends it to the pid.
321 * No failure notifications.
323 void audit_send_reply(int pid
, int seq
, int type
, int done
, int multi
,
324 void *payload
, int size
)
327 struct nlmsghdr
*nlh
;
328 int len
= NLMSG_SPACE(size
);
330 int flags
= multi
? NLM_F_MULTI
: 0;
331 int t
= done
? NLMSG_DONE
: type
;
333 skb
= alloc_skb(len
, GFP_KERNEL
);
337 nlh
= NLMSG_PUT(skb
, pid
, seq
, t
, size
);
338 nlh
->nlmsg_flags
= flags
;
339 data
= NLMSG_DATA(nlh
);
340 memcpy(data
, payload
, size
);
342 /* Ignore failure. It'll only happen if the sender goes away,
343 because our timeout is set to infinite. */
344 netlink_unicast(audit_sock
, skb
, pid
, 0);
347 nlmsg_failure
: /* Used by NLMSG_PUT */
353 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
356 static int audit_netlink_ok(kernel_cap_t eff_cap
, u16 msg_type
)
366 case AUDIT_SIGNAL_INFO
:
367 if (!cap_raised(eff_cap
, CAP_AUDIT_CONTROL
))
371 case AUDIT_FIRST_USER_MSG
...AUDIT_LAST_USER_MSG
:
372 case AUDIT_FIRST_USER_MSG2
...AUDIT_LAST_USER_MSG2
:
373 if (!cap_raised(eff_cap
, CAP_AUDIT_WRITE
))
376 default: /* bad msg */
383 static int audit_receive_msg(struct sk_buff
*skb
, struct nlmsghdr
*nlh
)
387 struct audit_status
*status_get
, status_set
;
389 struct audit_buffer
*ab
;
390 u16 msg_type
= nlh
->nlmsg_type
;
391 uid_t loginuid
; /* loginuid of sender */
392 struct audit_sig_info sig_data
;
394 err
= audit_netlink_ok(NETLINK_CB(skb
).eff_cap
, msg_type
);
398 /* As soon as there's any sign of userspace auditd,
399 * start kauditd to talk to it */
401 kauditd_task
= kthread_run(kauditd_thread
, NULL
, "kauditd");
402 if (IS_ERR(kauditd_task
)) {
403 err
= PTR_ERR(kauditd_task
);
408 pid
= NETLINK_CREDS(skb
)->pid
;
409 uid
= NETLINK_CREDS(skb
)->uid
;
410 loginuid
= NETLINK_CB(skb
).loginuid
;
411 seq
= nlh
->nlmsg_seq
;
412 data
= NLMSG_DATA(nlh
);
416 status_set
.enabled
= audit_enabled
;
417 status_set
.failure
= audit_failure
;
418 status_set
.pid
= audit_pid
;
419 status_set
.rate_limit
= audit_rate_limit
;
420 status_set
.backlog_limit
= audit_backlog_limit
;
421 status_set
.lost
= atomic_read(&audit_lost
);
422 status_set
.backlog
= skb_queue_len(&audit_skb_queue
);
423 audit_send_reply(NETLINK_CB(skb
).pid
, seq
, AUDIT_GET
, 0, 0,
424 &status_set
, sizeof(status_set
));
427 if (nlh
->nlmsg_len
< sizeof(struct audit_status
))
429 status_get
= (struct audit_status
*)data
;
430 if (status_get
->mask
& AUDIT_STATUS_ENABLED
) {
431 err
= audit_set_enabled(status_get
->enabled
, loginuid
);
432 if (err
< 0) return err
;
434 if (status_get
->mask
& AUDIT_STATUS_FAILURE
) {
435 err
= audit_set_failure(status_get
->failure
, loginuid
);
436 if (err
< 0) return err
;
438 if (status_get
->mask
& AUDIT_STATUS_PID
) {
440 audit_pid
= status_get
->pid
;
441 audit_log(NULL
, GFP_KERNEL
, AUDIT_CONFIG_CHANGE
,
442 "audit_pid=%d old=%d by auid=%u",
443 audit_pid
, old
, loginuid
);
445 if (status_get
->mask
& AUDIT_STATUS_RATE_LIMIT
)
446 audit_set_rate_limit(status_get
->rate_limit
, loginuid
);
447 if (status_get
->mask
& AUDIT_STATUS_BACKLOG_LIMIT
)
448 audit_set_backlog_limit(status_get
->backlog_limit
,
452 case AUDIT_FIRST_USER_MSG
...AUDIT_LAST_USER_MSG
:
453 case AUDIT_FIRST_USER_MSG2
...AUDIT_LAST_USER_MSG2
:
454 if (!audit_enabled
&& msg_type
!= AUDIT_USER_AVC
)
457 err
= audit_filter_user(&NETLINK_CB(skb
), msg_type
);
460 ab
= audit_log_start(NULL
, GFP_KERNEL
, msg_type
);
463 "user pid=%d uid=%u auid=%u msg='%.1024s'",
464 pid
, uid
, loginuid
, (char *)data
);
465 audit_set_pid(ab
, pid
);
472 if (nlh
->nlmsg_len
< sizeof(struct audit_rule
))
476 err
= audit_receive_filter(nlh
->nlmsg_type
, NETLINK_CB(skb
).pid
,
477 uid
, seq
, data
, loginuid
);
479 case AUDIT_SIGNAL_INFO
:
480 sig_data
.uid
= audit_sig_uid
;
481 sig_data
.pid
= audit_sig_pid
;
482 audit_send_reply(NETLINK_CB(skb
).pid
, seq
, AUDIT_SIGNAL_INFO
,
483 0, 0, &sig_data
, sizeof(sig_data
));
490 return err
< 0 ? err
: 0;
494 * Get message from skb (based on rtnetlink_rcv_skb). Each message is
495 * processed by audit_receive_msg. Malformed skbs with wrong length are
496 * discarded silently.
498 static void audit_receive_skb(struct sk_buff
*skb
)
501 struct nlmsghdr
*nlh
;
504 while (skb
->len
>= NLMSG_SPACE(0)) {
505 nlh
= (struct nlmsghdr
*)skb
->data
;
506 if (nlh
->nlmsg_len
< sizeof(*nlh
) || skb
->len
< nlh
->nlmsg_len
)
508 rlen
= NLMSG_ALIGN(nlh
->nlmsg_len
);
511 if ((err
= audit_receive_msg(skb
, nlh
))) {
512 netlink_ack(skb
, nlh
, err
);
513 } else if (nlh
->nlmsg_flags
& NLM_F_ACK
)
514 netlink_ack(skb
, nlh
, 0);
519 /* Receive messages from netlink socket. */
520 static void audit_receive(struct sock
*sk
, int length
)
525 down(&audit_netlink_sem
);
527 for (qlen
= skb_queue_len(&sk
->sk_receive_queue
); qlen
; qlen
--) {
528 skb
= skb_dequeue(&sk
->sk_receive_queue
);
529 audit_receive_skb(skb
);
532 up(&audit_netlink_sem
);
536 /* Initialize audit support at boot time. */
537 static int __init
audit_init(void)
539 printk(KERN_INFO
"audit: initializing netlink socket (%s)\n",
540 audit_default
? "enabled" : "disabled");
541 audit_sock
= netlink_kernel_create(NETLINK_AUDIT
, 0, audit_receive
,
544 audit_panic("cannot initialize netlink socket");
546 audit_sock
->sk_sndtimeo
= MAX_SCHEDULE_TIMEOUT
;
547 skb_queue_head_init(&audit_skb_queue
);
548 audit_initialized
= 1;
549 audit_enabled
= audit_default
;
550 audit_log(NULL
, GFP_KERNEL
, AUDIT_KERNEL
, "initialized");
553 __initcall(audit_init
);
555 /* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
556 static int __init
audit_enable(char *str
)
558 audit_default
= !!simple_strtol(str
, NULL
, 0);
559 printk(KERN_INFO
"audit: %s%s\n",
560 audit_default
? "enabled" : "disabled",
561 audit_initialized
? "" : " (after initialization)");
562 if (audit_initialized
)
563 audit_enabled
= audit_default
;
567 __setup("audit=", audit_enable
);
569 static void audit_buffer_free(struct audit_buffer
*ab
)
579 spin_lock_irqsave(&audit_freelist_lock
, flags
);
580 if (++audit_freelist_count
> AUDIT_MAXFREE
)
583 list_add(&ab
->list
, &audit_freelist
);
584 spin_unlock_irqrestore(&audit_freelist_lock
, flags
);
587 static struct audit_buffer
* audit_buffer_alloc(struct audit_context
*ctx
,
588 gfp_t gfp_mask
, int type
)
591 struct audit_buffer
*ab
= NULL
;
592 struct nlmsghdr
*nlh
;
594 spin_lock_irqsave(&audit_freelist_lock
, flags
);
595 if (!list_empty(&audit_freelist
)) {
596 ab
= list_entry(audit_freelist
.next
,
597 struct audit_buffer
, list
);
599 --audit_freelist_count
;
601 spin_unlock_irqrestore(&audit_freelist_lock
, flags
);
604 ab
= kmalloc(sizeof(*ab
), gfp_mask
);
609 ab
->skb
= alloc_skb(AUDIT_BUFSIZ
, gfp_mask
);
614 ab
->gfp_mask
= gfp_mask
;
615 nlh
= (struct nlmsghdr
*)skb_put(ab
->skb
, NLMSG_SPACE(0));
616 nlh
->nlmsg_type
= type
;
617 nlh
->nlmsg_flags
= 0;
622 audit_buffer_free(ab
);
627 * audit_serial - compute a serial number for the audit record
629 * Compute a serial number for the audit record. Audit records are
630 * written to user-space as soon as they are generated, so a complete
631 * audit record may be written in several pieces. The timestamp of the
632 * record and this serial number are used by the user-space tools to
633 * determine which pieces belong to the same audit record. The
634 * (timestamp,serial) tuple is unique for each syscall and is live from
635 * syscall entry to syscall exit.
637 * NOTE: Another possibility is to store the formatted records off the
638 * audit context (for those records that have a context), and emit them
639 * all at syscall exit. However, this could delay the reporting of
640 * significant errors until syscall exit (or never, if the system
643 unsigned int audit_serial(void)
645 static spinlock_t serial_lock
= SPIN_LOCK_UNLOCKED
;
646 static unsigned int serial
= 0;
651 spin_lock_irqsave(&serial_lock
, flags
);
654 } while (unlikely(!ret
));
655 spin_unlock_irqrestore(&serial_lock
, flags
);
660 static inline void audit_get_stamp(struct audit_context
*ctx
,
661 struct timespec
*t
, unsigned int *serial
)
664 auditsc_get_stamp(ctx
, t
, serial
);
667 *serial
= audit_serial();
671 /* Obtain an audit buffer. This routine does locking to obtain the
672 * audit buffer, but then no locking is required for calls to
673 * audit_log_*format. If the tsk is a task that is currently in a
674 * syscall, then the syscall is marked as auditable and an audit record
675 * will be written at syscall exit. If there is no associated task, tsk
679 * audit_log_start - obtain an audit buffer
680 * @ctx: audit_context (may be NULL)
681 * @gfp_mask: type of allocation
682 * @type: audit message type
684 * Returns audit_buffer pointer on success or NULL on error.
686 * Obtain an audit buffer. This routine does locking to obtain the
687 * audit buffer, but then no locking is required for calls to
688 * audit_log_*format. If the task (ctx) is a task that is currently in a
689 * syscall, then the syscall is marked as auditable and an audit record
690 * will be written at syscall exit. If there is no associated task, then
691 * task context (ctx) should be NULL.
693 struct audit_buffer
*audit_log_start(struct audit_context
*ctx
, gfp_t gfp_mask
,
696 struct audit_buffer
*ab
= NULL
;
700 unsigned long timeout_start
= jiffies
;
702 if (!audit_initialized
)
705 if (gfp_mask
& __GFP_WAIT
)
708 reserve
= 5; /* Allow atomic callers to go up to five
709 entries over the normal backlog limit */
711 while (audit_backlog_limit
712 && skb_queue_len(&audit_skb_queue
) > audit_backlog_limit
+ reserve
) {
713 if (gfp_mask
& __GFP_WAIT
&& audit_backlog_wait_time
714 && time_before(jiffies
, timeout_start
+ audit_backlog_wait_time
)) {
716 /* Wait for auditd to drain the queue a little */
717 DECLARE_WAITQUEUE(wait
, current
);
718 set_current_state(TASK_INTERRUPTIBLE
);
719 add_wait_queue(&audit_backlog_wait
, &wait
);
721 if (audit_backlog_limit
&&
722 skb_queue_len(&audit_skb_queue
) > audit_backlog_limit
)
723 schedule_timeout(timeout_start
+ audit_backlog_wait_time
- jiffies
);
725 __set_current_state(TASK_RUNNING
);
726 remove_wait_queue(&audit_backlog_wait
, &wait
);
729 if (audit_rate_check())
731 "audit: audit_backlog=%d > "
732 "audit_backlog_limit=%d\n",
733 skb_queue_len(&audit_skb_queue
),
734 audit_backlog_limit
);
735 audit_log_lost("backlog limit exceeded");
736 audit_backlog_wait_time
= audit_backlog_wait_overflow
;
737 wake_up(&audit_backlog_wait
);
741 ab
= audit_buffer_alloc(ctx
, gfp_mask
, type
);
743 audit_log_lost("out of memory in audit_log_start");
747 audit_get_stamp(ab
->ctx
, &t
, &serial
);
749 audit_log_format(ab
, "audit(%lu.%03lu:%u): ",
750 t
.tv_sec
, t
.tv_nsec
/1000000, serial
);
755 * audit_expand - expand skb in the audit buffer
757 * @extra: space to add at tail of the skb
759 * Returns 0 (no space) on failed expansion, or available space if
762 static inline int audit_expand(struct audit_buffer
*ab
, int extra
)
764 struct sk_buff
*skb
= ab
->skb
;
765 int ret
= pskb_expand_head(skb
, skb_headroom(skb
), extra
,
768 audit_log_lost("out of memory in audit_expand");
771 return skb_tailroom(skb
);
775 * Format an audit message into the audit buffer. If there isn't enough
776 * room in the audit buffer, more room will be allocated and vsnprint
777 * will be called a second time. Currently, we assume that a printk
778 * can't format message larger than 1024 bytes, so we don't either.
780 static void audit_log_vformat(struct audit_buffer
*ab
, const char *fmt
,
792 avail
= skb_tailroom(skb
);
794 avail
= audit_expand(ab
, AUDIT_BUFSIZ
);
798 va_copy(args2
, args
);
799 len
= vsnprintf(skb
->tail
, avail
, fmt
, args
);
801 /* The printk buffer is 1024 bytes long, so if we get
802 * here and AUDIT_BUFSIZ is at least 1024, then we can
803 * log everything that printk could have logged. */
804 avail
= audit_expand(ab
,
805 max_t(unsigned, AUDIT_BUFSIZ
, 1+len
-avail
));
808 len
= vsnprintf(skb
->tail
, avail
, fmt
, args2
);
817 * audit_log_format - format a message into the audit buffer.
819 * @fmt: format string
820 * @...: optional parameters matching @fmt string
822 * All the work is done in audit_log_vformat.
824 void audit_log_format(struct audit_buffer
*ab
, const char *fmt
, ...)
831 audit_log_vformat(ab
, fmt
, args
);
836 * audit_log_hex - convert a buffer to hex and append it to the audit skb
837 * @ab: the audit_buffer
838 * @buf: buffer to convert to hex
839 * @len: length of @buf to be converted
841 * No return value; failure to expand is silently ignored.
843 * This function will take the passed buf and convert it into a string of
844 * ascii hex digits. The new string is placed onto the skb.
846 void audit_log_hex(struct audit_buffer
*ab
, const unsigned char *buf
,
849 int i
, avail
, new_len
;
852 static const unsigned char *hex
= "0123456789ABCDEF";
856 avail
= skb_tailroom(skb
);
858 if (new_len
>= avail
) {
859 /* Round the buffer request up to the next multiple */
860 new_len
= AUDIT_BUFSIZ
*(((new_len
-avail
)/AUDIT_BUFSIZ
) + 1);
861 avail
= audit_expand(ab
, new_len
);
867 for (i
=0; i
<len
; i
++) {
868 *ptr
++ = hex
[(buf
[i
] & 0xF0)>>4]; /* Upper nibble */
869 *ptr
++ = hex
[buf
[i
] & 0x0F]; /* Lower nibble */
872 skb_put(skb
, len
<< 1); /* new string is twice the old string */
876 * audit_log_unstrustedstring - log a string that may contain random characters
878 * @string: string to be logged
880 * This code will escape a string that is passed to it if the string
881 * contains a control character, unprintable character, double quote mark,
882 * or a space. Unescaped strings will start and end with a double quote mark.
883 * Strings that are escaped are printed in hex (2 digits per char).
885 void audit_log_untrustedstring(struct audit_buffer
*ab
, const char *string
)
887 const unsigned char *p
= string
;
890 if (*p
== '"' || *p
< 0x21 || *p
> 0x7f) {
891 audit_log_hex(ab
, string
, strlen(string
));
896 audit_log_format(ab
, "\"%s\"", string
);
899 /* This is a helper-function to print the escaped d_path */
900 void audit_log_d_path(struct audit_buffer
*ab
, const char *prefix
,
901 struct dentry
*dentry
, struct vfsmount
*vfsmnt
)
906 audit_log_format(ab
, " %s", prefix
);
908 /* We will allow 11 spaces for ' (deleted)' to be appended */
909 path
= kmalloc(PATH_MAX
+11, ab
->gfp_mask
);
911 audit_log_format(ab
, "<no memory>");
914 p
= d_path(dentry
, vfsmnt
, path
, PATH_MAX
+11);
915 if (IS_ERR(p
)) { /* Should never happen since we send PATH_MAX */
916 /* FIXME: can we save some information here? */
917 audit_log_format(ab
, "<too long>");
919 audit_log_untrustedstring(ab
, p
);
924 * audit_log_end - end one audit record
925 * @ab: the audit_buffer
927 * The netlink_* functions cannot be called inside an irq context, so
928 * the audit buffer is placed on a queue and a tasklet is scheduled to
929 * remove them from the queue outside the irq context. May be called in
932 void audit_log_end(struct audit_buffer
*ab
)
936 if (!audit_rate_check()) {
937 audit_log_lost("rate limit exceeded");
940 struct nlmsghdr
*nlh
= (struct nlmsghdr
*)ab
->skb
->data
;
941 nlh
->nlmsg_len
= ab
->skb
->len
- NLMSG_SPACE(0);
942 skb_queue_tail(&audit_skb_queue
, ab
->skb
);
944 wake_up_interruptible(&kauditd_wait
);
946 printk(KERN_NOTICE
"%s\n", ab
->skb
->data
+ NLMSG_SPACE(0));
949 audit_buffer_free(ab
);
953 * audit_log - Log an audit record
954 * @ctx: audit context
955 * @gfp_mask: type of allocation
956 * @type: audit message type
957 * @fmt: format string to use
958 * @...: variable parameters matching the format string
960 * This is a convenience function that calls audit_log_start,
961 * audit_log_vformat, and audit_log_end. It may be called
964 void audit_log(struct audit_context
*ctx
, gfp_t gfp_mask
, int type
,
965 const char *fmt
, ...)
967 struct audit_buffer
*ab
;
970 ab
= audit_log_start(ctx
, gfp_mask
, type
);
973 audit_log_vformat(ab
, fmt
, args
);