1 /* audit.c -- Auditing support
2 * Gateway between the kernel (e.g., selinux) and the user-space audit daemon.
3 * System-call specific features have moved to auditsc.c
5 * Copyright 2003-2007 Red Hat Inc., Durham, North Carolina.
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 * Written by Rickard E. (Rik) Faith <faith@redhat.com>
24 * Goals: 1) Integrate fully with Security Modules.
25 * 2) Minimal run-time overhead:
26 * a) Minimal when syscall auditing is disabled (audit_enable=0).
27 * b) Small when syscall auditing is enabled and no audit record
28 * is generated (defer as much work as possible to record
30 * i) context is allocated,
31 * ii) names from getname are stored without a copy, and
32 * iii) inode information stored from path_lookup.
33 * 3) Ability to disable syscall auditing at boot time (audit=0).
34 * 4) Usable by other parts of the kernel (if audit_log* is called,
35 * then a syscall record will be generated automatically for the
37 * 5) Netlink interface to user-space.
38 * 6) Support low-overhead kernel-based filtering to minimize the
39 * information that must be passed to user-space.
41 * Example user-space utilities: http://people.redhat.com/sgrubb/audit/
44 #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/inotify.h>
59 #include <linux/freezer.h>
60 #include <linux/tty.h>
64 /* No auditing will take place until audit_initialized != 0.
65 * (Initialization happens after skb_init is called.) */
66 static int audit_initialized
;
70 #define AUDIT_LOCKED 2
72 int audit_ever_enabled
;
74 /* Default state when kernel boots without any parameters. */
75 static int audit_default
;
77 /* If auditing cannot proceed, audit_failure selects what happens. */
78 static int audit_failure
= AUDIT_FAIL_PRINTK
;
81 * If audit records are to be written to the netlink socket, audit_pid
82 * contains the pid of the auditd process and audit_nlk_pid contains
83 * the pid to use to send netlink messages to that process.
86 static int audit_nlk_pid
;
88 /* If audit_rate_limit is non-zero, limit the rate of sending audit records
89 * to that number per second. This prevents DoS attacks, but results in
90 * audit records being dropped. */
91 static int audit_rate_limit
;
93 /* Number of outstanding audit_buffers allowed. */
94 static int audit_backlog_limit
= 64;
95 static int audit_backlog_wait_time
= 60 * HZ
;
96 static int audit_backlog_wait_overflow
= 0;
98 /* The identity of the user shutting down the audit system. */
99 uid_t audit_sig_uid
= -1;
100 pid_t audit_sig_pid
= -1;
101 u32 audit_sig_sid
= 0;
103 /* Records can be lost in several ways:
104 0) [suppressed in audit_alloc]
105 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
106 2) out of memory in audit_log_move [alloc_skb]
107 3) suppressed due to audit_rate_limit
108 4) suppressed due to audit_backlog_limit
110 static atomic_t audit_lost
= ATOMIC_INIT(0);
112 /* The netlink socket. */
113 static struct sock
*audit_sock
;
115 /* Inotify handle. */
116 struct inotify_handle
*audit_ih
;
118 /* Hash for inode-based rules */
119 struct list_head audit_inode_hash
[AUDIT_INODE_BUCKETS
];
121 /* The audit_freelist is a list of pre-allocated audit buffers (if more
122 * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
123 * being placed on the freelist). */
124 static DEFINE_SPINLOCK(audit_freelist_lock
);
125 static int audit_freelist_count
;
126 static LIST_HEAD(audit_freelist
);
128 static struct sk_buff_head audit_skb_queue
;
129 /* queue of skbs to send to auditd when/if it comes back */
130 static struct sk_buff_head audit_skb_hold_queue
;
131 static struct task_struct
*kauditd_task
;
132 static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait
);
133 static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait
);
135 /* Serialize requests from userspace. */
136 static DEFINE_MUTEX(audit_cmd_mutex
);
138 /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
139 * audit records. Since printk uses a 1024 byte buffer, this buffer
140 * should be at least that large. */
141 #define AUDIT_BUFSIZ 1024
143 /* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the
144 * audit_freelist. Doing so eliminates many kmalloc/kfree calls. */
145 #define AUDIT_MAXFREE (2*NR_CPUS)
147 /* The audit_buffer is used when formatting an audit record. The caller
148 * locks briefly to get the record off the freelist or to allocate the
149 * buffer, and locks briefly to send the buffer to the netlink layer or
150 * to place it on a transmit queue. Multiple audit_buffers can be in
151 * use simultaneously. */
152 struct audit_buffer
{
153 struct list_head list
;
154 struct sk_buff
*skb
; /* formatted skb ready to send */
155 struct audit_context
*ctx
; /* NULL or associated context */
164 static void audit_set_pid(struct audit_buffer
*ab
, pid_t pid
)
167 struct nlmsghdr
*nlh
= nlmsg_hdr(ab
->skb
);
168 nlh
->nlmsg_pid
= pid
;
172 void audit_panic(const char *message
)
174 switch (audit_failure
)
176 case AUDIT_FAIL_SILENT
:
178 case AUDIT_FAIL_PRINTK
:
179 if (printk_ratelimit())
180 printk(KERN_ERR
"audit: %s\n", message
);
182 case AUDIT_FAIL_PANIC
:
183 /* test audit_pid since printk is always losey, why bother? */
185 panic("audit: %s\n", message
);
190 static inline int audit_rate_check(void)
192 static unsigned long last_check
= 0;
193 static int messages
= 0;
194 static DEFINE_SPINLOCK(lock
);
197 unsigned long elapsed
;
200 if (!audit_rate_limit
) return 1;
202 spin_lock_irqsave(&lock
, flags
);
203 if (++messages
< audit_rate_limit
) {
207 elapsed
= now
- last_check
;
214 spin_unlock_irqrestore(&lock
, flags
);
220 * audit_log_lost - conditionally log lost audit message event
221 * @message: the message stating reason for lost audit message
223 * Emit at least 1 message per second, even if audit_rate_check is
225 * Always increment the lost messages counter.
227 void audit_log_lost(const char *message
)
229 static unsigned long last_msg
= 0;
230 static DEFINE_SPINLOCK(lock
);
235 atomic_inc(&audit_lost
);
237 print
= (audit_failure
== AUDIT_FAIL_PANIC
|| !audit_rate_limit
);
240 spin_lock_irqsave(&lock
, flags
);
242 if (now
- last_msg
> HZ
) {
246 spin_unlock_irqrestore(&lock
, flags
);
250 if (printk_ratelimit())
252 "audit: audit_lost=%d audit_rate_limit=%d "
253 "audit_backlog_limit=%d\n",
254 atomic_read(&audit_lost
),
256 audit_backlog_limit
);
257 audit_panic(message
);
261 static int audit_log_config_change(char *function_name
, int new, int old
,
262 uid_t loginuid
, u32 sessionid
, u32 sid
,
265 struct audit_buffer
*ab
;
268 ab
= audit_log_start(NULL
, GFP_KERNEL
, AUDIT_CONFIG_CHANGE
);
269 audit_log_format(ab
, "%s=%d old=%d auid=%u ses=%u", function_name
, new,
270 old
, loginuid
, sessionid
);
275 rc
= security_secid_to_secctx(sid
, &ctx
, &len
);
277 audit_log_format(ab
, " sid=%u", sid
);
278 allow_changes
= 0; /* Something weird, deny request */
280 audit_log_format(ab
, " subj=%s", ctx
);
281 security_release_secctx(ctx
, len
);
284 audit_log_format(ab
, " res=%d", allow_changes
);
289 static int audit_do_config_change(char *function_name
, int *to_change
,
290 int new, uid_t loginuid
, u32 sessionid
,
293 int allow_changes
, rc
= 0, old
= *to_change
;
295 /* check if we are locked */
296 if (audit_enabled
== AUDIT_LOCKED
)
301 if (audit_enabled
!= AUDIT_OFF
) {
302 rc
= audit_log_config_change(function_name
, new, old
, loginuid
,
303 sessionid
, sid
, allow_changes
);
308 /* If we are allowed, make the change */
309 if (allow_changes
== 1)
311 /* Not allowed, update reason */
317 static int audit_set_rate_limit(int limit
, uid_t loginuid
, u32 sessionid
,
320 return audit_do_config_change("audit_rate_limit", &audit_rate_limit
,
321 limit
, loginuid
, sessionid
, sid
);
324 static int audit_set_backlog_limit(int limit
, uid_t loginuid
, u32 sessionid
,
327 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit
,
328 limit
, loginuid
, sessionid
, sid
);
331 static int audit_set_enabled(int state
, uid_t loginuid
, u32 sessionid
, u32 sid
)
334 if (state
< AUDIT_OFF
|| state
> AUDIT_LOCKED
)
337 rc
= audit_do_config_change("audit_enabled", &audit_enabled
, state
,
338 loginuid
, sessionid
, sid
);
341 audit_ever_enabled
|= !!state
;
346 static int audit_set_failure(int state
, uid_t loginuid
, u32 sessionid
, u32 sid
)
348 if (state
!= AUDIT_FAIL_SILENT
349 && state
!= AUDIT_FAIL_PRINTK
350 && state
!= AUDIT_FAIL_PANIC
)
353 return audit_do_config_change("audit_failure", &audit_failure
, state
,
354 loginuid
, sessionid
, sid
);
358 * Queue skbs to be sent to auditd when/if it comes back. These skbs should
359 * already have been sent via prink/syslog and so if these messages are dropped
360 * it is not a huge concern since we already passed the audit_log_lost()
361 * notification and stuff. This is just nice to get audit messages during
362 * boot before auditd is running or messages generated while auditd is stopped.
363 * This only holds messages is audit_default is set, aka booting with audit=1
364 * or building your kernel that way.
366 static void audit_hold_skb(struct sk_buff
*skb
)
369 skb_queue_len(&audit_skb_hold_queue
) < audit_backlog_limit
)
370 skb_queue_tail(&audit_skb_hold_queue
, skb
);
375 static void kauditd_send_skb(struct sk_buff
*skb
)
378 /* take a reference in case we can't send it and we want to hold it */
380 err
= netlink_unicast(audit_sock
, skb
, audit_nlk_pid
, 0);
382 BUG_ON(err
!= -ECONNREFUSED
); /* Shoudn't happen */
383 printk(KERN_ERR
"audit: *NO* daemon at audit_pid=%d\n", audit_pid
);
384 audit_log_lost("auditd dissapeared\n");
386 /* we might get lucky and get this in the next auditd */
389 /* drop the extra reference if sent ok */
393 static int kauditd_thread(void *dummy
)
398 while (!kthread_should_stop()) {
400 * if auditd just started drain the queue of messages already
401 * sent to syslog/printk. remember loss here is ok. we already
402 * called audit_log_lost() if it didn't go out normally. so the
403 * race between the skb_dequeue and the next check for audit_pid
406 * if you ever find kauditd to be too slow we can get a perf win
407 * by doing our own locking and keeping better track if there
408 * are messages in this queue. I don't see the need now, but
409 * in 5 years when I want to play with this again I'll see this
410 * note and still have no friggin idea what i'm thinking today.
412 if (audit_default
&& audit_pid
) {
413 skb
= skb_dequeue(&audit_skb_hold_queue
);
415 while (skb
&& audit_pid
) {
416 kauditd_send_skb(skb
);
417 skb
= skb_dequeue(&audit_skb_hold_queue
);
422 skb
= skb_dequeue(&audit_skb_queue
);
423 wake_up(&audit_backlog_wait
);
426 kauditd_send_skb(skb
);
428 if (printk_ratelimit())
429 printk(KERN_NOTICE
"%s\n", skb
->data
+ NLMSG_SPACE(0));
431 audit_log_lost("printk limit exceeded\n");
436 DECLARE_WAITQUEUE(wait
, current
);
437 set_current_state(TASK_INTERRUPTIBLE
);
438 add_wait_queue(&kauditd_wait
, &wait
);
440 if (!skb_queue_len(&audit_skb_queue
)) {
445 __set_current_state(TASK_RUNNING
);
446 remove_wait_queue(&kauditd_wait
, &wait
);
452 static int audit_prepare_user_tty(pid_t pid
, uid_t loginuid
, u32 sessionid
)
454 struct task_struct
*tsk
;
457 read_lock(&tasklist_lock
);
458 tsk
= find_task_by_vpid(pid
);
464 spin_lock_irq(&tsk
->sighand
->siglock
);
465 if (!tsk
->signal
->audit_tty
)
467 spin_unlock_irq(&tsk
->sighand
->siglock
);
471 tty_audit_push_task(tsk
, loginuid
, sessionid
);
473 read_unlock(&tasklist_lock
);
477 int audit_send_list(void *_dest
)
479 struct audit_netlink_list
*dest
= _dest
;
483 /* wait for parent to finish and send an ACK */
484 mutex_lock(&audit_cmd_mutex
);
485 mutex_unlock(&audit_cmd_mutex
);
487 while ((skb
= __skb_dequeue(&dest
->q
)) != NULL
)
488 netlink_unicast(audit_sock
, skb
, pid
, 0);
495 #ifdef CONFIG_AUDIT_TREE
496 static int prune_tree_thread(void *unused
)
498 mutex_lock(&audit_cmd_mutex
);
500 mutex_unlock(&audit_cmd_mutex
);
504 void audit_schedule_prune(void)
506 kthread_run(prune_tree_thread
, NULL
, "audit_prune_tree");
510 struct sk_buff
*audit_make_reply(int pid
, int seq
, int type
, int done
,
511 int multi
, void *payload
, int size
)
514 struct nlmsghdr
*nlh
;
515 int len
= NLMSG_SPACE(size
);
517 int flags
= multi
? NLM_F_MULTI
: 0;
518 int t
= done
? NLMSG_DONE
: type
;
520 skb
= alloc_skb(len
, GFP_KERNEL
);
524 nlh
= NLMSG_PUT(skb
, pid
, seq
, t
, size
);
525 nlh
->nlmsg_flags
= flags
;
526 data
= NLMSG_DATA(nlh
);
527 memcpy(data
, payload
, size
);
530 nlmsg_failure
: /* Used by NLMSG_PUT */
536 static int audit_send_reply_thread(void *arg
)
538 struct audit_reply
*reply
= (struct audit_reply
*)arg
;
540 mutex_lock(&audit_cmd_mutex
);
541 mutex_unlock(&audit_cmd_mutex
);
543 /* Ignore failure. It'll only happen if the sender goes away,
544 because our timeout is set to infinite. */
545 netlink_unicast(audit_sock
, reply
->skb
, reply
->pid
, 0);
550 * audit_send_reply - send an audit reply message via netlink
551 * @pid: process id to send reply to
552 * @seq: sequence number
553 * @type: audit message type
554 * @done: done (last) flag
555 * @multi: multi-part message flag
556 * @payload: payload data
557 * @size: payload size
559 * Allocates an skb, builds the netlink message, and sends it to the pid.
560 * No failure notifications.
562 void audit_send_reply(int pid
, int seq
, int type
, int done
, int multi
,
563 void *payload
, int size
)
566 struct task_struct
*tsk
;
567 struct audit_reply
*reply
= kmalloc(sizeof(struct audit_reply
),
573 skb
= audit_make_reply(pid
, seq
, type
, done
, multi
, payload
, size
);
580 tsk
= kthread_run(audit_send_reply_thread
, reply
, "audit_send_reply");
589 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
592 static int audit_netlink_ok(struct sk_buff
*skb
, u16 msg_type
)
599 case AUDIT_LIST_RULES
:
605 case AUDIT_SIGNAL_INFO
:
609 case AUDIT_MAKE_EQUIV
:
610 if (security_netlink_recv(skb
, CAP_AUDIT_CONTROL
))
614 case AUDIT_FIRST_USER_MSG
... AUDIT_LAST_USER_MSG
:
615 case AUDIT_FIRST_USER_MSG2
... AUDIT_LAST_USER_MSG2
:
616 if (security_netlink_recv(skb
, CAP_AUDIT_WRITE
))
619 default: /* bad msg */
626 static int audit_log_common_recv_msg(struct audit_buffer
**ab
, u16 msg_type
,
627 u32 pid
, u32 uid
, uid_t auid
, u32 ses
,
634 if (!audit_enabled
) {
639 *ab
= audit_log_start(NULL
, GFP_KERNEL
, msg_type
);
640 audit_log_format(*ab
, "user pid=%d uid=%u auid=%u ses=%u",
641 pid
, uid
, auid
, ses
);
643 rc
= security_secid_to_secctx(sid
, &ctx
, &len
);
645 audit_log_format(*ab
, " ssid=%u", sid
);
647 audit_log_format(*ab
, " subj=%s", ctx
);
648 security_release_secctx(ctx
, len
);
655 static int audit_receive_msg(struct sk_buff
*skb
, struct nlmsghdr
*nlh
)
657 u32 uid
, pid
, seq
, sid
;
659 struct audit_status
*status_get
, status_set
;
661 struct audit_buffer
*ab
;
662 u16 msg_type
= nlh
->nlmsg_type
;
663 uid_t loginuid
; /* loginuid of sender */
665 struct audit_sig_info
*sig_data
;
669 err
= audit_netlink_ok(skb
, msg_type
);
673 /* As soon as there's any sign of userspace auditd,
674 * start kauditd to talk to it */
676 kauditd_task
= kthread_run(kauditd_thread
, NULL
, "kauditd");
677 if (IS_ERR(kauditd_task
)) {
678 err
= PTR_ERR(kauditd_task
);
683 pid
= NETLINK_CREDS(skb
)->pid
;
684 uid
= NETLINK_CREDS(skb
)->uid
;
685 loginuid
= NETLINK_CB(skb
).loginuid
;
686 sessionid
= NETLINK_CB(skb
).sessionid
;
687 sid
= NETLINK_CB(skb
).sid
;
688 seq
= nlh
->nlmsg_seq
;
689 data
= NLMSG_DATA(nlh
);
693 status_set
.enabled
= audit_enabled
;
694 status_set
.failure
= audit_failure
;
695 status_set
.pid
= audit_pid
;
696 status_set
.rate_limit
= audit_rate_limit
;
697 status_set
.backlog_limit
= audit_backlog_limit
;
698 status_set
.lost
= atomic_read(&audit_lost
);
699 status_set
.backlog
= skb_queue_len(&audit_skb_queue
);
700 audit_send_reply(NETLINK_CB(skb
).pid
, seq
, AUDIT_GET
, 0, 0,
701 &status_set
, sizeof(status_set
));
704 if (nlh
->nlmsg_len
< sizeof(struct audit_status
))
706 status_get
= (struct audit_status
*)data
;
707 if (status_get
->mask
& AUDIT_STATUS_ENABLED
) {
708 err
= audit_set_enabled(status_get
->enabled
,
709 loginuid
, sessionid
, sid
);
710 if (err
< 0) return err
;
712 if (status_get
->mask
& AUDIT_STATUS_FAILURE
) {
713 err
= audit_set_failure(status_get
->failure
,
714 loginuid
, sessionid
, sid
);
715 if (err
< 0) return err
;
717 if (status_get
->mask
& AUDIT_STATUS_PID
) {
718 int new_pid
= status_get
->pid
;
720 if (audit_enabled
!= AUDIT_OFF
)
721 audit_log_config_change("audit_pid", new_pid
,
726 audit_nlk_pid
= NETLINK_CB(skb
).pid
;
728 if (status_get
->mask
& AUDIT_STATUS_RATE_LIMIT
)
729 err
= audit_set_rate_limit(status_get
->rate_limit
,
730 loginuid
, sessionid
, sid
);
731 if (status_get
->mask
& AUDIT_STATUS_BACKLOG_LIMIT
)
732 err
= audit_set_backlog_limit(status_get
->backlog_limit
,
733 loginuid
, sessionid
, sid
);
736 case AUDIT_FIRST_USER_MSG
... AUDIT_LAST_USER_MSG
:
737 case AUDIT_FIRST_USER_MSG2
... AUDIT_LAST_USER_MSG2
:
738 if (!audit_enabled
&& msg_type
!= AUDIT_USER_AVC
)
741 err
= audit_filter_user(&NETLINK_CB(skb
), msg_type
);
744 if (msg_type
== AUDIT_USER_TTY
) {
745 err
= audit_prepare_user_tty(pid
, loginuid
,
750 audit_log_common_recv_msg(&ab
, msg_type
, pid
, uid
,
751 loginuid
, sessionid
, sid
);
753 if (msg_type
!= AUDIT_USER_TTY
)
754 audit_log_format(ab
, " msg='%.1024s'",
759 audit_log_format(ab
, " msg=");
760 size
= nlmsg_len(nlh
);
761 audit_log_n_untrustedstring(ab
, data
, size
);
763 audit_set_pid(ab
, pid
);
769 if (nlmsg_len(nlh
) < sizeof(struct audit_rule
))
771 if (audit_enabled
== AUDIT_LOCKED
) {
772 audit_log_common_recv_msg(&ab
, AUDIT_CONFIG_CHANGE
, pid
,
773 uid
, loginuid
, sessionid
, sid
);
775 audit_log_format(ab
, " audit_enabled=%d res=0",
782 err
= audit_receive_filter(nlh
->nlmsg_type
, NETLINK_CB(skb
).pid
,
783 uid
, seq
, data
, nlmsg_len(nlh
),
784 loginuid
, sessionid
, sid
);
788 if (nlmsg_len(nlh
) < sizeof(struct audit_rule_data
))
790 if (audit_enabled
== AUDIT_LOCKED
) {
791 audit_log_common_recv_msg(&ab
, AUDIT_CONFIG_CHANGE
, pid
,
792 uid
, loginuid
, sessionid
, sid
);
794 audit_log_format(ab
, " audit_enabled=%d res=0",
800 case AUDIT_LIST_RULES
:
801 err
= audit_receive_filter(nlh
->nlmsg_type
, NETLINK_CB(skb
).pid
,
802 uid
, seq
, data
, nlmsg_len(nlh
),
803 loginuid
, sessionid
, sid
);
808 audit_log_common_recv_msg(&ab
, AUDIT_CONFIG_CHANGE
, pid
,
809 uid
, loginuid
, sessionid
, sid
);
811 audit_log_format(ab
, " op=trim res=1");
814 case AUDIT_MAKE_EQUIV
: {
817 size_t msglen
= nlmsg_len(nlh
);
821 if (msglen
< 2 * sizeof(u32
))
823 memcpy(sizes
, bufp
, 2 * sizeof(u32
));
824 bufp
+= 2 * sizeof(u32
);
825 msglen
-= 2 * sizeof(u32
);
826 old
= audit_unpack_string(&bufp
, &msglen
, sizes
[0]);
831 new = audit_unpack_string(&bufp
, &msglen
, sizes
[1]);
837 /* OK, here comes... */
838 err
= audit_tag_tree(old
, new);
840 audit_log_common_recv_msg(&ab
, AUDIT_CONFIG_CHANGE
, pid
,
841 uid
, loginuid
, sessionid
, sid
);
843 audit_log_format(ab
, " op=make_equiv old=");
844 audit_log_untrustedstring(ab
, old
);
845 audit_log_format(ab
, " new=");
846 audit_log_untrustedstring(ab
, new);
847 audit_log_format(ab
, " res=%d", !err
);
853 case AUDIT_SIGNAL_INFO
:
854 err
= security_secid_to_secctx(audit_sig_sid
, &ctx
, &len
);
857 sig_data
= kmalloc(sizeof(*sig_data
) + len
, GFP_KERNEL
);
859 security_release_secctx(ctx
, len
);
862 sig_data
->uid
= audit_sig_uid
;
863 sig_data
->pid
= audit_sig_pid
;
864 memcpy(sig_data
->ctx
, ctx
, len
);
865 security_release_secctx(ctx
, len
);
866 audit_send_reply(NETLINK_CB(skb
).pid
, seq
, AUDIT_SIGNAL_INFO
,
867 0, 0, sig_data
, sizeof(*sig_data
) + len
);
870 case AUDIT_TTY_GET
: {
871 struct audit_tty_status s
;
872 struct task_struct
*tsk
;
874 read_lock(&tasklist_lock
);
875 tsk
= find_task_by_vpid(pid
);
879 spin_lock_irq(&tsk
->sighand
->siglock
);
880 s
.enabled
= tsk
->signal
->audit_tty
!= 0;
881 spin_unlock_irq(&tsk
->sighand
->siglock
);
883 read_unlock(&tasklist_lock
);
884 audit_send_reply(NETLINK_CB(skb
).pid
, seq
, AUDIT_TTY_GET
, 0, 0,
888 case AUDIT_TTY_SET
: {
889 struct audit_tty_status
*s
;
890 struct task_struct
*tsk
;
892 if (nlh
->nlmsg_len
< sizeof(struct audit_tty_status
))
895 if (s
->enabled
!= 0 && s
->enabled
!= 1)
897 read_lock(&tasklist_lock
);
898 tsk
= find_task_by_vpid(pid
);
902 spin_lock_irq(&tsk
->sighand
->siglock
);
903 tsk
->signal
->audit_tty
= s
->enabled
!= 0;
904 spin_unlock_irq(&tsk
->sighand
->siglock
);
906 read_unlock(&tasklist_lock
);
914 return err
< 0 ? err
: 0;
918 * Get message from skb (based on rtnetlink_rcv_skb). Each message is
919 * processed by audit_receive_msg. Malformed skbs with wrong length are
920 * discarded silently.
922 static void audit_receive_skb(struct sk_buff
*skb
)
925 struct nlmsghdr
*nlh
;
928 while (skb
->len
>= NLMSG_SPACE(0)) {
929 nlh
= nlmsg_hdr(skb
);
930 if (nlh
->nlmsg_len
< sizeof(*nlh
) || skb
->len
< nlh
->nlmsg_len
)
932 rlen
= NLMSG_ALIGN(nlh
->nlmsg_len
);
935 if ((err
= audit_receive_msg(skb
, nlh
))) {
936 netlink_ack(skb
, nlh
, err
);
937 } else if (nlh
->nlmsg_flags
& NLM_F_ACK
)
938 netlink_ack(skb
, nlh
, 0);
943 /* Receive messages from netlink socket. */
944 static void audit_receive(struct sk_buff
*skb
)
946 mutex_lock(&audit_cmd_mutex
);
947 audit_receive_skb(skb
);
948 mutex_unlock(&audit_cmd_mutex
);
951 #ifdef CONFIG_AUDITSYSCALL
952 static const struct inotify_operations audit_inotify_ops
= {
953 .handle_event
= audit_handle_ievent
,
954 .destroy_watch
= audit_free_parent
,
958 /* Initialize audit support at boot time. */
959 static int __init
audit_init(void)
963 printk(KERN_INFO
"audit: initializing netlink socket (%s)\n",
964 audit_default
? "enabled" : "disabled");
965 audit_sock
= netlink_kernel_create(&init_net
, NETLINK_AUDIT
, 0,
966 audit_receive
, NULL
, THIS_MODULE
);
968 audit_panic("cannot initialize netlink socket");
970 audit_sock
->sk_sndtimeo
= MAX_SCHEDULE_TIMEOUT
;
972 skb_queue_head_init(&audit_skb_queue
);
973 skb_queue_head_init(&audit_skb_hold_queue
);
974 audit_initialized
= 1;
975 audit_enabled
= audit_default
;
976 audit_ever_enabled
|= !!audit_default
;
978 audit_log(NULL
, GFP_KERNEL
, AUDIT_KERNEL
, "initialized");
980 #ifdef CONFIG_AUDITSYSCALL
981 audit_ih
= inotify_init(&audit_inotify_ops
);
982 if (IS_ERR(audit_ih
))
983 audit_panic("cannot initialize inotify handle");
986 for (i
= 0; i
< AUDIT_INODE_BUCKETS
; i
++)
987 INIT_LIST_HEAD(&audit_inode_hash
[i
]);
991 __initcall(audit_init
);
993 /* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
994 static int __init
audit_enable(char *str
)
996 audit_default
= !!simple_strtol(str
, NULL
, 0);
997 printk(KERN_INFO
"audit: %s%s\n",
998 audit_default
? "enabled" : "disabled",
999 audit_initialized
? "" : " (after initialization)");
1000 if (audit_initialized
) {
1001 audit_enabled
= audit_default
;
1002 audit_ever_enabled
|= !!audit_default
;
1007 __setup("audit=", audit_enable
);
1009 static void audit_buffer_free(struct audit_buffer
*ab
)
1011 unsigned long flags
;
1019 spin_lock_irqsave(&audit_freelist_lock
, flags
);
1020 if (audit_freelist_count
> AUDIT_MAXFREE
)
1023 audit_freelist_count
++;
1024 list_add(&ab
->list
, &audit_freelist
);
1026 spin_unlock_irqrestore(&audit_freelist_lock
, flags
);
1029 static struct audit_buffer
* audit_buffer_alloc(struct audit_context
*ctx
,
1030 gfp_t gfp_mask
, int type
)
1032 unsigned long flags
;
1033 struct audit_buffer
*ab
= NULL
;
1034 struct nlmsghdr
*nlh
;
1036 spin_lock_irqsave(&audit_freelist_lock
, flags
);
1037 if (!list_empty(&audit_freelist
)) {
1038 ab
= list_entry(audit_freelist
.next
,
1039 struct audit_buffer
, list
);
1040 list_del(&ab
->list
);
1041 --audit_freelist_count
;
1043 spin_unlock_irqrestore(&audit_freelist_lock
, flags
);
1046 ab
= kmalloc(sizeof(*ab
), gfp_mask
);
1051 ab
->skb
= alloc_skb(AUDIT_BUFSIZ
, gfp_mask
);
1056 ab
->gfp_mask
= gfp_mask
;
1057 nlh
= (struct nlmsghdr
*)skb_put(ab
->skb
, NLMSG_SPACE(0));
1058 nlh
->nlmsg_type
= type
;
1059 nlh
->nlmsg_flags
= 0;
1064 audit_buffer_free(ab
);
1069 * audit_serial - compute a serial number for the audit record
1071 * Compute a serial number for the audit record. Audit records are
1072 * written to user-space as soon as they are generated, so a complete
1073 * audit record may be written in several pieces. The timestamp of the
1074 * record and this serial number are used by the user-space tools to
1075 * determine which pieces belong to the same audit record. The
1076 * (timestamp,serial) tuple is unique for each syscall and is live from
1077 * syscall entry to syscall exit.
1079 * NOTE: Another possibility is to store the formatted records off the
1080 * audit context (for those records that have a context), and emit them
1081 * all at syscall exit. However, this could delay the reporting of
1082 * significant errors until syscall exit (or never, if the system
1085 unsigned int audit_serial(void)
1087 static DEFINE_SPINLOCK(serial_lock
);
1088 static unsigned int serial
= 0;
1090 unsigned long flags
;
1093 spin_lock_irqsave(&serial_lock
, flags
);
1096 } while (unlikely(!ret
));
1097 spin_unlock_irqrestore(&serial_lock
, flags
);
1102 static inline void audit_get_stamp(struct audit_context
*ctx
,
1103 struct timespec
*t
, unsigned int *serial
)
1106 auditsc_get_stamp(ctx
, t
, serial
);
1109 *serial
= audit_serial();
1113 /* Obtain an audit buffer. This routine does locking to obtain the
1114 * audit buffer, but then no locking is required for calls to
1115 * audit_log_*format. If the tsk is a task that is currently in a
1116 * syscall, then the syscall is marked as auditable and an audit record
1117 * will be written at syscall exit. If there is no associated task, tsk
1118 * should be NULL. */
1121 * audit_log_start - obtain an audit buffer
1122 * @ctx: audit_context (may be NULL)
1123 * @gfp_mask: type of allocation
1124 * @type: audit message type
1126 * Returns audit_buffer pointer on success or NULL on error.
1128 * Obtain an audit buffer. This routine does locking to obtain the
1129 * audit buffer, but then no locking is required for calls to
1130 * audit_log_*format. If the task (ctx) is a task that is currently in a
1131 * syscall, then the syscall is marked as auditable and an audit record
1132 * will be written at syscall exit. If there is no associated task, then
1133 * task context (ctx) should be NULL.
1135 struct audit_buffer
*audit_log_start(struct audit_context
*ctx
, gfp_t gfp_mask
,
1138 struct audit_buffer
*ab
= NULL
;
1140 unsigned int uninitialized_var(serial
);
1142 unsigned long timeout_start
= jiffies
;
1144 if (!audit_initialized
)
1147 if (unlikely(audit_filter_type(type
)))
1150 if (gfp_mask
& __GFP_WAIT
)
1153 reserve
= 5; /* Allow atomic callers to go up to five
1154 entries over the normal backlog limit */
1156 while (audit_backlog_limit
1157 && skb_queue_len(&audit_skb_queue
) > audit_backlog_limit
+ reserve
) {
1158 if (gfp_mask
& __GFP_WAIT
&& audit_backlog_wait_time
1159 && time_before(jiffies
, timeout_start
+ audit_backlog_wait_time
)) {
1161 /* Wait for auditd to drain the queue a little */
1162 DECLARE_WAITQUEUE(wait
, current
);
1163 set_current_state(TASK_INTERRUPTIBLE
);
1164 add_wait_queue(&audit_backlog_wait
, &wait
);
1166 if (audit_backlog_limit
&&
1167 skb_queue_len(&audit_skb_queue
) > audit_backlog_limit
)
1168 schedule_timeout(timeout_start
+ audit_backlog_wait_time
- jiffies
);
1170 __set_current_state(TASK_RUNNING
);
1171 remove_wait_queue(&audit_backlog_wait
, &wait
);
1174 if (audit_rate_check() && printk_ratelimit())
1176 "audit: audit_backlog=%d > "
1177 "audit_backlog_limit=%d\n",
1178 skb_queue_len(&audit_skb_queue
),
1179 audit_backlog_limit
);
1180 audit_log_lost("backlog limit exceeded");
1181 audit_backlog_wait_time
= audit_backlog_wait_overflow
;
1182 wake_up(&audit_backlog_wait
);
1186 ab
= audit_buffer_alloc(ctx
, gfp_mask
, type
);
1188 audit_log_lost("out of memory in audit_log_start");
1192 audit_get_stamp(ab
->ctx
, &t
, &serial
);
1194 audit_log_format(ab
, "audit(%lu.%03lu:%u): ",
1195 t
.tv_sec
, t
.tv_nsec
/1000000, serial
);
1200 * audit_expand - expand skb in the audit buffer
1202 * @extra: space to add at tail of the skb
1204 * Returns 0 (no space) on failed expansion, or available space if
1207 static inline int audit_expand(struct audit_buffer
*ab
, int extra
)
1209 struct sk_buff
*skb
= ab
->skb
;
1210 int oldtail
= skb_tailroom(skb
);
1211 int ret
= pskb_expand_head(skb
, 0, extra
, ab
->gfp_mask
);
1212 int newtail
= skb_tailroom(skb
);
1215 audit_log_lost("out of memory in audit_expand");
1219 skb
->truesize
+= newtail
- oldtail
;
1224 * Format an audit message into the audit buffer. If there isn't enough
1225 * room in the audit buffer, more room will be allocated and vsnprint
1226 * will be called a second time. Currently, we assume that a printk
1227 * can't format message larger than 1024 bytes, so we don't either.
1229 static void audit_log_vformat(struct audit_buffer
*ab
, const char *fmt
,
1233 struct sk_buff
*skb
;
1241 avail
= skb_tailroom(skb
);
1243 avail
= audit_expand(ab
, AUDIT_BUFSIZ
);
1247 va_copy(args2
, args
);
1248 len
= vsnprintf(skb_tail_pointer(skb
), avail
, fmt
, args
);
1250 /* The printk buffer is 1024 bytes long, so if we get
1251 * here and AUDIT_BUFSIZ is at least 1024, then we can
1252 * log everything that printk could have logged. */
1253 avail
= audit_expand(ab
,
1254 max_t(unsigned, AUDIT_BUFSIZ
, 1+len
-avail
));
1257 len
= vsnprintf(skb_tail_pointer(skb
), avail
, fmt
, args2
);
1267 * audit_log_format - format a message into the audit buffer.
1269 * @fmt: format string
1270 * @...: optional parameters matching @fmt string
1272 * All the work is done in audit_log_vformat.
1274 void audit_log_format(struct audit_buffer
*ab
, const char *fmt
, ...)
1280 va_start(args
, fmt
);
1281 audit_log_vformat(ab
, fmt
, args
);
1286 * audit_log_hex - convert a buffer to hex and append it to the audit skb
1287 * @ab: the audit_buffer
1288 * @buf: buffer to convert to hex
1289 * @len: length of @buf to be converted
1291 * No return value; failure to expand is silently ignored.
1293 * This function will take the passed buf and convert it into a string of
1294 * ascii hex digits. The new string is placed onto the skb.
1296 void audit_log_n_hex(struct audit_buffer
*ab
, const unsigned char *buf
,
1299 int i
, avail
, new_len
;
1301 struct sk_buff
*skb
;
1302 static const unsigned char *hex
= "0123456789ABCDEF";
1309 avail
= skb_tailroom(skb
);
1311 if (new_len
>= avail
) {
1312 /* Round the buffer request up to the next multiple */
1313 new_len
= AUDIT_BUFSIZ
*(((new_len
-avail
)/AUDIT_BUFSIZ
) + 1);
1314 avail
= audit_expand(ab
, new_len
);
1319 ptr
= skb_tail_pointer(skb
);
1320 for (i
=0; i
<len
; i
++) {
1321 *ptr
++ = hex
[(buf
[i
] & 0xF0)>>4]; /* Upper nibble */
1322 *ptr
++ = hex
[buf
[i
] & 0x0F]; /* Lower nibble */
1325 skb_put(skb
, len
<< 1); /* new string is twice the old string */
1329 * Format a string of no more than slen characters into the audit buffer,
1330 * enclosed in quote marks.
1332 void audit_log_n_string(struct audit_buffer
*ab
, const char *string
,
1337 struct sk_buff
*skb
;
1344 avail
= skb_tailroom(skb
);
1345 new_len
= slen
+ 3; /* enclosing quotes + null terminator */
1346 if (new_len
> avail
) {
1347 avail
= audit_expand(ab
, new_len
);
1351 ptr
= skb_tail_pointer(skb
);
1353 memcpy(ptr
, string
, slen
);
1357 skb_put(skb
, slen
+ 2); /* don't include null terminator */
1361 * audit_string_contains_control - does a string need to be logged in hex
1362 * @string: string to be checked
1363 * @len: max length of the string to check
1365 int audit_string_contains_control(const char *string
, size_t len
)
1367 const unsigned char *p
;
1368 for (p
= string
; p
< (const unsigned char *)string
+ len
&& *p
; p
++) {
1369 if (*p
== '"' || *p
< 0x21 || *p
> 0x7f)
1376 * audit_log_n_untrustedstring - log a string that may contain random characters
1378 * @len: length of string (not including trailing null)
1379 * @string: string to be logged
1381 * This code will escape a string that is passed to it if the string
1382 * contains a control character, unprintable character, double quote mark,
1383 * or a space. Unescaped strings will start and end with a double quote mark.
1384 * Strings that are escaped are printed in hex (2 digits per char).
1386 * The caller specifies the number of characters in the string to log, which may
1387 * or may not be the entire string.
1389 void audit_log_n_untrustedstring(struct audit_buffer
*ab
, const char *string
,
1392 if (audit_string_contains_control(string
, len
))
1393 audit_log_n_hex(ab
, string
, len
);
1395 audit_log_n_string(ab
, string
, len
);
1399 * audit_log_untrustedstring - log a string that may contain random characters
1401 * @string: string to be logged
1403 * Same as audit_log_n_untrustedstring(), except that strlen is used to
1404 * determine string length.
1406 void audit_log_untrustedstring(struct audit_buffer
*ab
, const char *string
)
1408 audit_log_n_untrustedstring(ab
, string
, strlen(string
));
1411 /* This is a helper-function to print the escaped d_path */
1412 void audit_log_d_path(struct audit_buffer
*ab
, const char *prefix
,
1418 audit_log_format(ab
, " %s", prefix
);
1420 /* We will allow 11 spaces for ' (deleted)' to be appended */
1421 pathname
= kmalloc(PATH_MAX
+11, ab
->gfp_mask
);
1423 audit_log_format(ab
, "<no memory>");
1426 p
= d_path(path
, pathname
, PATH_MAX
+11);
1427 if (IS_ERR(p
)) { /* Should never happen since we send PATH_MAX */
1428 /* FIXME: can we save some information here? */
1429 audit_log_format(ab
, "<too long>");
1431 audit_log_untrustedstring(ab
, p
);
1436 * audit_log_end - end one audit record
1437 * @ab: the audit_buffer
1439 * The netlink_* functions cannot be called inside an irq context, so
1440 * the audit buffer is placed on a queue and a tasklet is scheduled to
1441 * remove them from the queue outside the irq context. May be called in
1444 void audit_log_end(struct audit_buffer
*ab
)
1448 if (!audit_rate_check()) {
1449 audit_log_lost("rate limit exceeded");
1451 struct nlmsghdr
*nlh
= nlmsg_hdr(ab
->skb
);
1452 nlh
->nlmsg_len
= ab
->skb
->len
- NLMSG_SPACE(0);
1455 skb_queue_tail(&audit_skb_queue
, ab
->skb
);
1456 wake_up_interruptible(&kauditd_wait
);
1458 if (nlh
->nlmsg_type
!= AUDIT_EOE
) {
1459 if (printk_ratelimit()) {
1460 printk(KERN_NOTICE
"type=%d %s\n",
1462 ab
->skb
->data
+ NLMSG_SPACE(0));
1464 audit_log_lost("printk limit exceeded\n");
1466 audit_hold_skb(ab
->skb
);
1470 audit_buffer_free(ab
);
1474 * audit_log - Log an audit record
1475 * @ctx: audit context
1476 * @gfp_mask: type of allocation
1477 * @type: audit message type
1478 * @fmt: format string to use
1479 * @...: variable parameters matching the format string
1481 * This is a convenience function that calls audit_log_start,
1482 * audit_log_vformat, and audit_log_end. It may be called
1485 void audit_log(struct audit_context
*ctx
, gfp_t gfp_mask
, int type
,
1486 const char *fmt
, ...)
1488 struct audit_buffer
*ab
;
1491 ab
= audit_log_start(ctx
, gfp_mask
, type
);
1493 va_start(args
, fmt
);
1494 audit_log_vformat(ab
, fmt
, args
);
1500 EXPORT_SYMBOL(audit_log_start
);
1501 EXPORT_SYMBOL(audit_log_end
);
1502 EXPORT_SYMBOL(audit_log_format
);
1503 EXPORT_SYMBOL(audit_log
);