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>
59 /* No auditing will take place until audit_initialized != 0.
60 * (Initialization happens after skb_init is called.) */
61 static int audit_initialized
;
63 /* No syscall auditing will take place unless audit_enabled != 0. */
66 /* Default state when kernel boots without any parameters. */
67 static int audit_default
;
69 /* If auditing cannot proceed, audit_failure selects what happens. */
70 static int audit_failure
= AUDIT_FAIL_PRINTK
;
72 /* If audit records are to be written to the netlink socket, audit_pid
73 * contains the (non-zero) pid. */
76 /* If audit_rate_limit is non-zero, limit the rate of sending audit records
77 * to that number per second. This prevents DoS attacks, but results in
78 * audit records being dropped. */
79 static int audit_rate_limit
;
81 /* Number of outstanding audit_buffers allowed. */
82 static int audit_backlog_limit
= 64;
83 static int audit_backlog_wait_time
= 60 * HZ
;
84 static int audit_backlog_wait_overflow
= 0;
86 /* The identity of the user shutting down the audit system. */
87 uid_t audit_sig_uid
= -1;
88 pid_t audit_sig_pid
= -1;
90 /* Records can be lost in several ways:
91 0) [suppressed in audit_alloc]
92 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
93 2) out of memory in audit_log_move [alloc_skb]
94 3) suppressed due to audit_rate_limit
95 4) suppressed due to audit_backlog_limit
97 static atomic_t audit_lost
= ATOMIC_INIT(0);
99 /* The netlink socket. */
100 static struct sock
*audit_sock
;
102 /* The audit_freelist is a list of pre-allocated audit buffers (if more
103 * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
104 * being placed on the freelist). */
105 static DEFINE_SPINLOCK(audit_freelist_lock
);
106 static int audit_freelist_count
;
107 static LIST_HEAD(audit_freelist
);
109 static struct sk_buff_head audit_skb_queue
;
110 static struct task_struct
*kauditd_task
;
111 static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait
);
112 static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait
);
114 /* The netlink socket is only to be read by 1 CPU, which lets us assume
115 * that list additions and deletions never happen simultaneously in
117 DEFINE_MUTEX(audit_netlink_mutex
);
119 /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
120 * audit records. Since printk uses a 1024 byte buffer, this buffer
121 * should be at least that large. */
122 #define AUDIT_BUFSIZ 1024
124 /* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the
125 * audit_freelist. Doing so eliminates many kmalloc/kfree calls. */
126 #define AUDIT_MAXFREE (2*NR_CPUS)
128 /* The audit_buffer is used when formatting an audit record. The caller
129 * locks briefly to get the record off the freelist or to allocate the
130 * buffer, and locks briefly to send the buffer to the netlink layer or
131 * to place it on a transmit queue. Multiple audit_buffers can be in
132 * use simultaneously. */
133 struct audit_buffer
{
134 struct list_head list
;
135 struct sk_buff
*skb
; /* formatted skb ready to send */
136 struct audit_context
*ctx
; /* NULL or associated context */
140 static void audit_set_pid(struct audit_buffer
*ab
, pid_t pid
)
142 struct nlmsghdr
*nlh
= (struct nlmsghdr
*)ab
->skb
->data
;
143 nlh
->nlmsg_pid
= pid
;
146 void audit_panic(const char *message
)
148 switch (audit_failure
)
150 case AUDIT_FAIL_SILENT
:
152 case AUDIT_FAIL_PRINTK
:
153 printk(KERN_ERR
"audit: %s\n", message
);
155 case AUDIT_FAIL_PANIC
:
156 panic("audit: %s\n", message
);
161 static inline int audit_rate_check(void)
163 static unsigned long last_check
= 0;
164 static int messages
= 0;
165 static DEFINE_SPINLOCK(lock
);
168 unsigned long elapsed
;
171 if (!audit_rate_limit
) return 1;
173 spin_lock_irqsave(&lock
, flags
);
174 if (++messages
< audit_rate_limit
) {
178 elapsed
= now
- last_check
;
185 spin_unlock_irqrestore(&lock
, flags
);
191 * audit_log_lost - conditionally log lost audit message event
192 * @message: the message stating reason for lost audit message
194 * Emit at least 1 message per second, even if audit_rate_check is
196 * Always increment the lost messages counter.
198 void audit_log_lost(const char *message
)
200 static unsigned long last_msg
= 0;
201 static DEFINE_SPINLOCK(lock
);
206 atomic_inc(&audit_lost
);
208 print
= (audit_failure
== AUDIT_FAIL_PANIC
|| !audit_rate_limit
);
211 spin_lock_irqsave(&lock
, flags
);
213 if (now
- last_msg
> HZ
) {
217 spin_unlock_irqrestore(&lock
, flags
);
222 "audit: audit_lost=%d audit_rate_limit=%d audit_backlog_limit=%d\n",
223 atomic_read(&audit_lost
),
225 audit_backlog_limit
);
226 audit_panic(message
);
230 static int audit_set_rate_limit(int limit
, uid_t loginuid
)
232 int old
= audit_rate_limit
;
233 audit_rate_limit
= limit
;
234 audit_log(NULL
, GFP_KERNEL
, AUDIT_CONFIG_CHANGE
,
235 "audit_rate_limit=%d old=%d by auid=%u",
236 audit_rate_limit
, old
, loginuid
);
240 static int audit_set_backlog_limit(int limit
, uid_t loginuid
)
242 int old
= audit_backlog_limit
;
243 audit_backlog_limit
= limit
;
244 audit_log(NULL
, GFP_KERNEL
, AUDIT_CONFIG_CHANGE
,
245 "audit_backlog_limit=%d old=%d by auid=%u",
246 audit_backlog_limit
, old
, loginuid
);
250 static int audit_set_enabled(int state
, uid_t loginuid
)
252 int old
= audit_enabled
;
253 if (state
!= 0 && state
!= 1)
255 audit_enabled
= state
;
256 audit_log(NULL
, GFP_KERNEL
, AUDIT_CONFIG_CHANGE
,
257 "audit_enabled=%d old=%d by auid=%u",
258 audit_enabled
, old
, loginuid
);
262 static int audit_set_failure(int state
, uid_t loginuid
)
264 int old
= audit_failure
;
265 if (state
!= AUDIT_FAIL_SILENT
266 && state
!= AUDIT_FAIL_PRINTK
267 && state
!= AUDIT_FAIL_PANIC
)
269 audit_failure
= state
;
270 audit_log(NULL
, GFP_KERNEL
, AUDIT_CONFIG_CHANGE
,
271 "audit_failure=%d old=%d by auid=%u",
272 audit_failure
, old
, loginuid
);
276 static int kauditd_thread(void *dummy
)
281 skb
= skb_dequeue(&audit_skb_queue
);
282 wake_up(&audit_backlog_wait
);
285 int err
= netlink_unicast(audit_sock
, skb
, audit_pid
, 0);
287 BUG_ON(err
!= -ECONNREFUSED
); /* Shoudn't happen */
288 printk(KERN_ERR
"audit: *NO* daemon at audit_pid=%d\n", audit_pid
);
292 printk(KERN_NOTICE
"%s\n", skb
->data
+ NLMSG_SPACE(0));
296 DECLARE_WAITQUEUE(wait
, current
);
297 set_current_state(TASK_INTERRUPTIBLE
);
298 add_wait_queue(&kauditd_wait
, &wait
);
300 if (!skb_queue_len(&audit_skb_queue
)) {
305 __set_current_state(TASK_RUNNING
);
306 remove_wait_queue(&kauditd_wait
, &wait
);
313 * audit_send_reply - send an audit reply message via netlink
314 * @pid: process id to send reply to
315 * @seq: sequence number
316 * @type: audit message type
317 * @done: done (last) flag
318 * @multi: multi-part message flag
319 * @payload: payload data
320 * @size: payload size
322 * Allocates an skb, builds the netlink message, and sends it to the pid.
323 * No failure notifications.
325 void audit_send_reply(int pid
, int seq
, int type
, int done
, int multi
,
326 void *payload
, int size
)
329 struct nlmsghdr
*nlh
;
330 int len
= NLMSG_SPACE(size
);
332 int flags
= multi
? NLM_F_MULTI
: 0;
333 int t
= done
? NLMSG_DONE
: type
;
335 skb
= alloc_skb(len
, GFP_KERNEL
);
339 nlh
= NLMSG_PUT(skb
, pid
, seq
, t
, size
);
340 nlh
->nlmsg_flags
= flags
;
341 data
= NLMSG_DATA(nlh
);
342 memcpy(data
, payload
, size
);
344 /* Ignore failure. It'll only happen if the sender goes away,
345 because our timeout is set to infinite. */
346 netlink_unicast(audit_sock
, skb
, pid
, 0);
349 nlmsg_failure
: /* Used by NLMSG_PUT */
355 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
358 static int audit_netlink_ok(kernel_cap_t eff_cap
, u16 msg_type
)
365 case AUDIT_LIST_RULES
:
371 case AUDIT_SIGNAL_INFO
:
372 if (!cap_raised(eff_cap
, CAP_AUDIT_CONTROL
))
376 case AUDIT_FIRST_USER_MSG
...AUDIT_LAST_USER_MSG
:
377 case AUDIT_FIRST_USER_MSG2
...AUDIT_LAST_USER_MSG2
:
378 if (!cap_raised(eff_cap
, CAP_AUDIT_WRITE
))
381 default: /* bad msg */
388 static int audit_receive_msg(struct sk_buff
*skb
, struct nlmsghdr
*nlh
)
392 struct audit_status
*status_get
, status_set
;
394 struct audit_buffer
*ab
;
395 u16 msg_type
= nlh
->nlmsg_type
;
396 uid_t loginuid
; /* loginuid of sender */
397 struct audit_sig_info sig_data
;
399 err
= audit_netlink_ok(NETLINK_CB(skb
).eff_cap
, msg_type
);
403 /* As soon as there's any sign of userspace auditd,
404 * start kauditd to talk to it */
406 kauditd_task
= kthread_run(kauditd_thread
, NULL
, "kauditd");
407 if (IS_ERR(kauditd_task
)) {
408 err
= PTR_ERR(kauditd_task
);
413 pid
= NETLINK_CREDS(skb
)->pid
;
414 uid
= NETLINK_CREDS(skb
)->uid
;
415 loginuid
= NETLINK_CB(skb
).loginuid
;
416 seq
= nlh
->nlmsg_seq
;
417 data
= NLMSG_DATA(nlh
);
421 status_set
.enabled
= audit_enabled
;
422 status_set
.failure
= audit_failure
;
423 status_set
.pid
= audit_pid
;
424 status_set
.rate_limit
= audit_rate_limit
;
425 status_set
.backlog_limit
= audit_backlog_limit
;
426 status_set
.lost
= atomic_read(&audit_lost
);
427 status_set
.backlog
= skb_queue_len(&audit_skb_queue
);
428 audit_send_reply(NETLINK_CB(skb
).pid
, seq
, AUDIT_GET
, 0, 0,
429 &status_set
, sizeof(status_set
));
432 if (nlh
->nlmsg_len
< sizeof(struct audit_status
))
434 status_get
= (struct audit_status
*)data
;
435 if (status_get
->mask
& AUDIT_STATUS_ENABLED
) {
436 err
= audit_set_enabled(status_get
->enabled
, loginuid
);
437 if (err
< 0) return err
;
439 if (status_get
->mask
& AUDIT_STATUS_FAILURE
) {
440 err
= audit_set_failure(status_get
->failure
, loginuid
);
441 if (err
< 0) return err
;
443 if (status_get
->mask
& AUDIT_STATUS_PID
) {
445 audit_pid
= status_get
->pid
;
446 audit_log(NULL
, GFP_KERNEL
, AUDIT_CONFIG_CHANGE
,
447 "audit_pid=%d old=%d by auid=%u",
448 audit_pid
, old
, loginuid
);
450 if (status_get
->mask
& AUDIT_STATUS_RATE_LIMIT
)
451 audit_set_rate_limit(status_get
->rate_limit
, loginuid
);
452 if (status_get
->mask
& AUDIT_STATUS_BACKLOG_LIMIT
)
453 audit_set_backlog_limit(status_get
->backlog_limit
,
457 case AUDIT_FIRST_USER_MSG
...AUDIT_LAST_USER_MSG
:
458 case AUDIT_FIRST_USER_MSG2
...AUDIT_LAST_USER_MSG2
:
459 if (!audit_enabled
&& msg_type
!= AUDIT_USER_AVC
)
462 err
= audit_filter_user(&NETLINK_CB(skb
), msg_type
);
465 ab
= audit_log_start(NULL
, GFP_KERNEL
, msg_type
);
468 "user pid=%d uid=%u auid=%u msg='%.1024s'",
469 pid
, uid
, loginuid
, (char *)data
);
470 audit_set_pid(ab
, pid
);
477 if (nlmsg_len(nlh
) < sizeof(struct audit_rule
))
481 err
= audit_receive_filter(nlh
->nlmsg_type
, NETLINK_CB(skb
).pid
,
482 uid
, seq
, data
, nlmsg_len(nlh
),
487 if (nlmsg_len(nlh
) < sizeof(struct audit_rule_data
))
490 case AUDIT_LIST_RULES
:
491 err
= audit_receive_filter(nlh
->nlmsg_type
, NETLINK_CB(skb
).pid
,
492 uid
, seq
, data
, nlmsg_len(nlh
),
495 case AUDIT_SIGNAL_INFO
:
496 sig_data
.uid
= audit_sig_uid
;
497 sig_data
.pid
= audit_sig_pid
;
498 audit_send_reply(NETLINK_CB(skb
).pid
, seq
, AUDIT_SIGNAL_INFO
,
499 0, 0, &sig_data
, sizeof(sig_data
));
506 return err
< 0 ? err
: 0;
510 * Get message from skb (based on rtnetlink_rcv_skb). Each message is
511 * processed by audit_receive_msg. Malformed skbs with wrong length are
512 * discarded silently.
514 static void audit_receive_skb(struct sk_buff
*skb
)
517 struct nlmsghdr
*nlh
;
520 while (skb
->len
>= NLMSG_SPACE(0)) {
521 nlh
= (struct nlmsghdr
*)skb
->data
;
522 if (nlh
->nlmsg_len
< sizeof(*nlh
) || skb
->len
< nlh
->nlmsg_len
)
524 rlen
= NLMSG_ALIGN(nlh
->nlmsg_len
);
527 if ((err
= audit_receive_msg(skb
, nlh
))) {
528 netlink_ack(skb
, nlh
, err
);
529 } else if (nlh
->nlmsg_flags
& NLM_F_ACK
)
530 netlink_ack(skb
, nlh
, 0);
535 /* Receive messages from netlink socket. */
536 static void audit_receive(struct sock
*sk
, int length
)
541 mutex_lock(&audit_netlink_mutex
);
543 for (qlen
= skb_queue_len(&sk
->sk_receive_queue
); qlen
; qlen
--) {
544 skb
= skb_dequeue(&sk
->sk_receive_queue
);
545 audit_receive_skb(skb
);
548 mutex_unlock(&audit_netlink_mutex
);
552 /* Initialize audit support at boot time. */
553 static int __init
audit_init(void)
555 printk(KERN_INFO
"audit: initializing netlink socket (%s)\n",
556 audit_default
? "enabled" : "disabled");
557 audit_sock
= netlink_kernel_create(NETLINK_AUDIT
, 0, audit_receive
,
560 audit_panic("cannot initialize netlink socket");
562 audit_sock
->sk_sndtimeo
= MAX_SCHEDULE_TIMEOUT
;
564 skb_queue_head_init(&audit_skb_queue
);
565 audit_initialized
= 1;
566 audit_enabled
= audit_default
;
567 audit_log(NULL
, GFP_KERNEL
, AUDIT_KERNEL
, "initialized");
570 __initcall(audit_init
);
572 /* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
573 static int __init
audit_enable(char *str
)
575 audit_default
= !!simple_strtol(str
, NULL
, 0);
576 printk(KERN_INFO
"audit: %s%s\n",
577 audit_default
? "enabled" : "disabled",
578 audit_initialized
? "" : " (after initialization)");
579 if (audit_initialized
)
580 audit_enabled
= audit_default
;
584 __setup("audit=", audit_enable
);
586 static void audit_buffer_free(struct audit_buffer
*ab
)
596 spin_lock_irqsave(&audit_freelist_lock
, flags
);
597 if (++audit_freelist_count
> AUDIT_MAXFREE
)
600 list_add(&ab
->list
, &audit_freelist
);
601 spin_unlock_irqrestore(&audit_freelist_lock
, flags
);
604 static struct audit_buffer
* audit_buffer_alloc(struct audit_context
*ctx
,
605 gfp_t gfp_mask
, int type
)
608 struct audit_buffer
*ab
= NULL
;
609 struct nlmsghdr
*nlh
;
611 spin_lock_irqsave(&audit_freelist_lock
, flags
);
612 if (!list_empty(&audit_freelist
)) {
613 ab
= list_entry(audit_freelist
.next
,
614 struct audit_buffer
, list
);
616 --audit_freelist_count
;
618 spin_unlock_irqrestore(&audit_freelist_lock
, flags
);
621 ab
= kmalloc(sizeof(*ab
), gfp_mask
);
626 ab
->skb
= alloc_skb(AUDIT_BUFSIZ
, gfp_mask
);
631 ab
->gfp_mask
= gfp_mask
;
632 nlh
= (struct nlmsghdr
*)skb_put(ab
->skb
, NLMSG_SPACE(0));
633 nlh
->nlmsg_type
= type
;
634 nlh
->nlmsg_flags
= 0;
639 audit_buffer_free(ab
);
644 * audit_serial - compute a serial number for the audit record
646 * Compute a serial number for the audit record. Audit records are
647 * written to user-space as soon as they are generated, so a complete
648 * audit record may be written in several pieces. The timestamp of the
649 * record and this serial number are used by the user-space tools to
650 * determine which pieces belong to the same audit record. The
651 * (timestamp,serial) tuple is unique for each syscall and is live from
652 * syscall entry to syscall exit.
654 * NOTE: Another possibility is to store the formatted records off the
655 * audit context (for those records that have a context), and emit them
656 * all at syscall exit. However, this could delay the reporting of
657 * significant errors until syscall exit (or never, if the system
660 unsigned int audit_serial(void)
662 static spinlock_t serial_lock
= SPIN_LOCK_UNLOCKED
;
663 static unsigned int serial
= 0;
668 spin_lock_irqsave(&serial_lock
, flags
);
671 } while (unlikely(!ret
));
672 spin_unlock_irqrestore(&serial_lock
, flags
);
677 static inline void audit_get_stamp(struct audit_context
*ctx
,
678 struct timespec
*t
, unsigned int *serial
)
681 auditsc_get_stamp(ctx
, t
, serial
);
684 *serial
= audit_serial();
688 /* Obtain an audit buffer. This routine does locking to obtain the
689 * audit buffer, but then no locking is required for calls to
690 * audit_log_*format. If the tsk is a task that is currently in a
691 * syscall, then the syscall is marked as auditable and an audit record
692 * will be written at syscall exit. If there is no associated task, tsk
696 * audit_log_start - obtain an audit buffer
697 * @ctx: audit_context (may be NULL)
698 * @gfp_mask: type of allocation
699 * @type: audit message type
701 * Returns audit_buffer pointer on success or NULL on error.
703 * Obtain an audit buffer. This routine does locking to obtain the
704 * audit buffer, but then no locking is required for calls to
705 * audit_log_*format. If the task (ctx) is a task that is currently in a
706 * syscall, then the syscall is marked as auditable and an audit record
707 * will be written at syscall exit. If there is no associated task, then
708 * task context (ctx) should be NULL.
710 struct audit_buffer
*audit_log_start(struct audit_context
*ctx
, gfp_t gfp_mask
,
713 struct audit_buffer
*ab
= NULL
;
717 unsigned long timeout_start
= jiffies
;
719 if (!audit_initialized
)
722 if (unlikely(audit_filter_type(type
)))
725 if (gfp_mask
& __GFP_WAIT
)
728 reserve
= 5; /* Allow atomic callers to go up to five
729 entries over the normal backlog limit */
731 while (audit_backlog_limit
732 && skb_queue_len(&audit_skb_queue
) > audit_backlog_limit
+ reserve
) {
733 if (gfp_mask
& __GFP_WAIT
&& audit_backlog_wait_time
734 && time_before(jiffies
, timeout_start
+ audit_backlog_wait_time
)) {
736 /* Wait for auditd to drain the queue a little */
737 DECLARE_WAITQUEUE(wait
, current
);
738 set_current_state(TASK_INTERRUPTIBLE
);
739 add_wait_queue(&audit_backlog_wait
, &wait
);
741 if (audit_backlog_limit
&&
742 skb_queue_len(&audit_skb_queue
) > audit_backlog_limit
)
743 schedule_timeout(timeout_start
+ audit_backlog_wait_time
- jiffies
);
745 __set_current_state(TASK_RUNNING
);
746 remove_wait_queue(&audit_backlog_wait
, &wait
);
749 if (audit_rate_check())
751 "audit: audit_backlog=%d > "
752 "audit_backlog_limit=%d\n",
753 skb_queue_len(&audit_skb_queue
),
754 audit_backlog_limit
);
755 audit_log_lost("backlog limit exceeded");
756 audit_backlog_wait_time
= audit_backlog_wait_overflow
;
757 wake_up(&audit_backlog_wait
);
761 ab
= audit_buffer_alloc(ctx
, gfp_mask
, type
);
763 audit_log_lost("out of memory in audit_log_start");
767 audit_get_stamp(ab
->ctx
, &t
, &serial
);
769 audit_log_format(ab
, "audit(%lu.%03lu:%u): ",
770 t
.tv_sec
, t
.tv_nsec
/1000000, serial
);
775 * audit_expand - expand skb in the audit buffer
777 * @extra: space to add at tail of the skb
779 * Returns 0 (no space) on failed expansion, or available space if
782 static inline int audit_expand(struct audit_buffer
*ab
, int extra
)
784 struct sk_buff
*skb
= ab
->skb
;
785 int ret
= pskb_expand_head(skb
, skb_headroom(skb
), extra
,
788 audit_log_lost("out of memory in audit_expand");
791 return skb_tailroom(skb
);
795 * Format an audit message into the audit buffer. If there isn't enough
796 * room in the audit buffer, more room will be allocated and vsnprint
797 * will be called a second time. Currently, we assume that a printk
798 * can't format message larger than 1024 bytes, so we don't either.
800 static void audit_log_vformat(struct audit_buffer
*ab
, const char *fmt
,
812 avail
= skb_tailroom(skb
);
814 avail
= audit_expand(ab
, AUDIT_BUFSIZ
);
818 va_copy(args2
, args
);
819 len
= vsnprintf(skb
->tail
, avail
, fmt
, args
);
821 /* The printk buffer is 1024 bytes long, so if we get
822 * here and AUDIT_BUFSIZ is at least 1024, then we can
823 * log everything that printk could have logged. */
824 avail
= audit_expand(ab
,
825 max_t(unsigned, AUDIT_BUFSIZ
, 1+len
-avail
));
828 len
= vsnprintf(skb
->tail
, avail
, fmt
, args2
);
837 * audit_log_format - format a message into the audit buffer.
839 * @fmt: format string
840 * @...: optional parameters matching @fmt string
842 * All the work is done in audit_log_vformat.
844 void audit_log_format(struct audit_buffer
*ab
, const char *fmt
, ...)
851 audit_log_vformat(ab
, fmt
, args
);
856 * audit_log_hex - convert a buffer to hex and append it to the audit skb
857 * @ab: the audit_buffer
858 * @buf: buffer to convert to hex
859 * @len: length of @buf to be converted
861 * No return value; failure to expand is silently ignored.
863 * This function will take the passed buf and convert it into a string of
864 * ascii hex digits. The new string is placed onto the skb.
866 void audit_log_hex(struct audit_buffer
*ab
, const unsigned char *buf
,
869 int i
, avail
, new_len
;
872 static const unsigned char *hex
= "0123456789ABCDEF";
876 avail
= skb_tailroom(skb
);
878 if (new_len
>= avail
) {
879 /* Round the buffer request up to the next multiple */
880 new_len
= AUDIT_BUFSIZ
*(((new_len
-avail
)/AUDIT_BUFSIZ
) + 1);
881 avail
= audit_expand(ab
, new_len
);
887 for (i
=0; i
<len
; i
++) {
888 *ptr
++ = hex
[(buf
[i
] & 0xF0)>>4]; /* Upper nibble */
889 *ptr
++ = hex
[buf
[i
] & 0x0F]; /* Lower nibble */
892 skb_put(skb
, len
<< 1); /* new string is twice the old string */
896 * audit_log_unstrustedstring - log a string that may contain random characters
898 * @string: string to be logged
900 * This code will escape a string that is passed to it if the string
901 * contains a control character, unprintable character, double quote mark,
902 * or a space. Unescaped strings will start and end with a double quote mark.
903 * Strings that are escaped are printed in hex (2 digits per char).
905 void audit_log_untrustedstring(struct audit_buffer
*ab
, const char *string
)
907 const unsigned char *p
= string
;
910 if (*p
== '"' || *p
< 0x21 || *p
> 0x7f) {
911 audit_log_hex(ab
, string
, strlen(string
));
916 audit_log_format(ab
, "\"%s\"", string
);
919 /* This is a helper-function to print the escaped d_path */
920 void audit_log_d_path(struct audit_buffer
*ab
, const char *prefix
,
921 struct dentry
*dentry
, struct vfsmount
*vfsmnt
)
926 audit_log_format(ab
, " %s", prefix
);
928 /* We will allow 11 spaces for ' (deleted)' to be appended */
929 path
= kmalloc(PATH_MAX
+11, ab
->gfp_mask
);
931 audit_log_format(ab
, "<no memory>");
934 p
= d_path(dentry
, vfsmnt
, path
, PATH_MAX
+11);
935 if (IS_ERR(p
)) { /* Should never happen since we send PATH_MAX */
936 /* FIXME: can we save some information here? */
937 audit_log_format(ab
, "<too long>");
939 audit_log_untrustedstring(ab
, p
);
944 * audit_log_end - end one audit record
945 * @ab: the audit_buffer
947 * The netlink_* functions cannot be called inside an irq context, so
948 * the audit buffer is placed on a queue and a tasklet is scheduled to
949 * remove them from the queue outside the irq context. May be called in
952 void audit_log_end(struct audit_buffer
*ab
)
956 if (!audit_rate_check()) {
957 audit_log_lost("rate limit exceeded");
960 struct nlmsghdr
*nlh
= (struct nlmsghdr
*)ab
->skb
->data
;
961 nlh
->nlmsg_len
= ab
->skb
->len
- NLMSG_SPACE(0);
962 skb_queue_tail(&audit_skb_queue
, ab
->skb
);
964 wake_up_interruptible(&kauditd_wait
);
966 printk(KERN_NOTICE
"%s\n", ab
->skb
->data
+ NLMSG_SPACE(0));
969 audit_buffer_free(ab
);
973 * audit_log - Log an audit record
974 * @ctx: audit context
975 * @gfp_mask: type of allocation
976 * @type: audit message type
977 * @fmt: format string to use
978 * @...: variable parameters matching the format string
980 * This is a convenience function that calls audit_log_start,
981 * audit_log_vformat, and audit_log_end. It may be called
984 void audit_log(struct audit_context
*ctx
, gfp_t gfp_mask
, int type
,
985 const char *fmt
, ...)
987 struct audit_buffer
*ab
;
990 ab
= audit_log_start(ctx
, gfp_mask
, type
);
993 audit_log_vformat(ab
, fmt
, args
);
999 EXPORT_SYMBOL(audit_log_start
);
1000 EXPORT_SYMBOL(audit_log_end
);
1001 EXPORT_SYMBOL(audit_log_format
);
1002 EXPORT_SYMBOL(audit_log
);