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 == AUDIT_INITIALIZED.
65 * (Initialization happens after skb_init is called.) */
66 #define AUDIT_DISABLED -1
67 #define AUDIT_UNINITIALIZED 0
68 #define AUDIT_INITIALIZED 1
69 static int audit_initialized
;
73 #define AUDIT_LOCKED 2
75 int audit_ever_enabled
;
77 /* Default state when kernel boots without any parameters. */
78 static int audit_default
;
80 /* If auditing cannot proceed, audit_failure selects what happens. */
81 static int audit_failure
= AUDIT_FAIL_PRINTK
;
84 * If audit records are to be written to the netlink socket, audit_pid
85 * contains the pid of the auditd process and audit_nlk_pid contains
86 * the pid to use to send netlink messages to that process.
89 static int audit_nlk_pid
;
91 /* If audit_rate_limit is non-zero, limit the rate of sending audit records
92 * to that number per second. This prevents DoS attacks, but results in
93 * audit records being dropped. */
94 static int audit_rate_limit
;
96 /* Number of outstanding audit_buffers allowed. */
97 static int audit_backlog_limit
= 64;
98 static int audit_backlog_wait_time
= 60 * HZ
;
99 static int audit_backlog_wait_overflow
= 0;
101 /* The identity of the user shutting down the audit system. */
102 uid_t audit_sig_uid
= -1;
103 pid_t audit_sig_pid
= -1;
104 u32 audit_sig_sid
= 0;
106 /* Records can be lost in several ways:
107 0) [suppressed in audit_alloc]
108 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
109 2) out of memory in audit_log_move [alloc_skb]
110 3) suppressed due to audit_rate_limit
111 4) suppressed due to audit_backlog_limit
113 static atomic_t audit_lost
= ATOMIC_INIT(0);
115 /* The netlink socket. */
116 static struct sock
*audit_sock
;
118 /* Inotify handle. */
119 struct inotify_handle
*audit_ih
;
121 /* Hash for inode-based rules */
122 struct list_head audit_inode_hash
[AUDIT_INODE_BUCKETS
];
124 /* The audit_freelist is a list of pre-allocated audit buffers (if more
125 * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
126 * being placed on the freelist). */
127 static DEFINE_SPINLOCK(audit_freelist_lock
);
128 static int audit_freelist_count
;
129 static LIST_HEAD(audit_freelist
);
131 static struct sk_buff_head audit_skb_queue
;
132 /* queue of skbs to send to auditd when/if it comes back */
133 static struct sk_buff_head audit_skb_hold_queue
;
134 static struct task_struct
*kauditd_task
;
135 static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait
);
136 static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait
);
138 /* Serialize requests from userspace. */
139 static DEFINE_MUTEX(audit_cmd_mutex
);
141 /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
142 * audit records. Since printk uses a 1024 byte buffer, this buffer
143 * should be at least that large. */
144 #define AUDIT_BUFSIZ 1024
146 /* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the
147 * audit_freelist. Doing so eliminates many kmalloc/kfree calls. */
148 #define AUDIT_MAXFREE (2*NR_CPUS)
150 /* The audit_buffer is used when formatting an audit record. The caller
151 * locks briefly to get the record off the freelist or to allocate the
152 * buffer, and locks briefly to send the buffer to the netlink layer or
153 * to place it on a transmit queue. Multiple audit_buffers can be in
154 * use simultaneously. */
155 struct audit_buffer
{
156 struct list_head list
;
157 struct sk_buff
*skb
; /* formatted skb ready to send */
158 struct audit_context
*ctx
; /* NULL or associated context */
167 static void audit_set_pid(struct audit_buffer
*ab
, pid_t pid
)
170 struct nlmsghdr
*nlh
= nlmsg_hdr(ab
->skb
);
171 nlh
->nlmsg_pid
= pid
;
175 void audit_panic(const char *message
)
177 switch (audit_failure
)
179 case AUDIT_FAIL_SILENT
:
181 case AUDIT_FAIL_PRINTK
:
182 if (printk_ratelimit())
183 printk(KERN_ERR
"audit: %s\n", message
);
185 case AUDIT_FAIL_PANIC
:
186 /* test audit_pid since printk is always losey, why bother? */
188 panic("audit: %s\n", message
);
193 static inline int audit_rate_check(void)
195 static unsigned long last_check
= 0;
196 static int messages
= 0;
197 static DEFINE_SPINLOCK(lock
);
200 unsigned long elapsed
;
203 if (!audit_rate_limit
) return 1;
205 spin_lock_irqsave(&lock
, flags
);
206 if (++messages
< audit_rate_limit
) {
210 elapsed
= now
- last_check
;
217 spin_unlock_irqrestore(&lock
, flags
);
223 * audit_log_lost - conditionally log lost audit message event
224 * @message: the message stating reason for lost audit message
226 * Emit at least 1 message per second, even if audit_rate_check is
228 * Always increment the lost messages counter.
230 void audit_log_lost(const char *message
)
232 static unsigned long last_msg
= 0;
233 static DEFINE_SPINLOCK(lock
);
238 atomic_inc(&audit_lost
);
240 print
= (audit_failure
== AUDIT_FAIL_PANIC
|| !audit_rate_limit
);
243 spin_lock_irqsave(&lock
, flags
);
245 if (now
- last_msg
> HZ
) {
249 spin_unlock_irqrestore(&lock
, flags
);
253 if (printk_ratelimit())
255 "audit: audit_lost=%d audit_rate_limit=%d "
256 "audit_backlog_limit=%d\n",
257 atomic_read(&audit_lost
),
259 audit_backlog_limit
);
260 audit_panic(message
);
264 static int audit_log_config_change(char *function_name
, int new, int old
,
265 uid_t loginuid
, u32 sessionid
, u32 sid
,
268 struct audit_buffer
*ab
;
271 ab
= audit_log_start(NULL
, GFP_KERNEL
, AUDIT_CONFIG_CHANGE
);
272 audit_log_format(ab
, "%s=%d old=%d auid=%u ses=%u", function_name
, new,
273 old
, loginuid
, sessionid
);
278 rc
= security_secid_to_secctx(sid
, &ctx
, &len
);
280 audit_log_format(ab
, " sid=%u", sid
);
281 allow_changes
= 0; /* Something weird, deny request */
283 audit_log_format(ab
, " subj=%s", ctx
);
284 security_release_secctx(ctx
, len
);
287 audit_log_format(ab
, " res=%d", allow_changes
);
292 static int audit_do_config_change(char *function_name
, int *to_change
,
293 int new, uid_t loginuid
, u32 sessionid
,
296 int allow_changes
, rc
= 0, old
= *to_change
;
298 /* check if we are locked */
299 if (audit_enabled
== AUDIT_LOCKED
)
304 if (audit_enabled
!= AUDIT_OFF
) {
305 rc
= audit_log_config_change(function_name
, new, old
, loginuid
,
306 sessionid
, sid
, allow_changes
);
311 /* If we are allowed, make the change */
312 if (allow_changes
== 1)
314 /* Not allowed, update reason */
320 static int audit_set_rate_limit(int limit
, uid_t loginuid
, u32 sessionid
,
323 return audit_do_config_change("audit_rate_limit", &audit_rate_limit
,
324 limit
, loginuid
, sessionid
, sid
);
327 static int audit_set_backlog_limit(int limit
, uid_t loginuid
, u32 sessionid
,
330 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit
,
331 limit
, loginuid
, sessionid
, sid
);
334 static int audit_set_enabled(int state
, uid_t loginuid
, u32 sessionid
, u32 sid
)
337 if (state
< AUDIT_OFF
|| state
> AUDIT_LOCKED
)
340 rc
= audit_do_config_change("audit_enabled", &audit_enabled
, state
,
341 loginuid
, sessionid
, sid
);
344 audit_ever_enabled
|= !!state
;
349 static int audit_set_failure(int state
, uid_t loginuid
, u32 sessionid
, u32 sid
)
351 if (state
!= AUDIT_FAIL_SILENT
352 && state
!= AUDIT_FAIL_PRINTK
353 && state
!= AUDIT_FAIL_PANIC
)
356 return audit_do_config_change("audit_failure", &audit_failure
, state
,
357 loginuid
, sessionid
, sid
);
361 * Queue skbs to be sent to auditd when/if it comes back. These skbs should
362 * already have been sent via prink/syslog and so if these messages are dropped
363 * it is not a huge concern since we already passed the audit_log_lost()
364 * notification and stuff. This is just nice to get audit messages during
365 * boot before auditd is running or messages generated while auditd is stopped.
366 * This only holds messages is audit_default is set, aka booting with audit=1
367 * or building your kernel that way.
369 static void audit_hold_skb(struct sk_buff
*skb
)
372 skb_queue_len(&audit_skb_hold_queue
) < audit_backlog_limit
)
373 skb_queue_tail(&audit_skb_hold_queue
, skb
);
379 * For one reason or another this nlh isn't getting delivered to the userspace
380 * audit daemon, just send it to printk.
382 static void audit_printk_skb(struct sk_buff
*skb
)
384 struct nlmsghdr
*nlh
= nlmsg_hdr(skb
);
385 char *data
= NLMSG_DATA(nlh
);
387 if (nlh
->nlmsg_type
!= AUDIT_EOE
) {
388 if (printk_ratelimit())
389 printk(KERN_NOTICE
"type=%d %s\n", nlh
->nlmsg_type
, data
);
391 audit_log_lost("printk limit exceeded\n");
397 static void kauditd_send_skb(struct sk_buff
*skb
)
400 /* take a reference in case we can't send it and we want to hold it */
402 err
= netlink_unicast(audit_sock
, skb
, audit_nlk_pid
, 0);
404 BUG_ON(err
!= -ECONNREFUSED
); /* Shoudn't happen */
405 printk(KERN_ERR
"audit: *NO* daemon at audit_pid=%d\n", audit_pid
);
406 audit_log_lost("auditd dissapeared\n");
408 /* we might get lucky and get this in the next auditd */
411 /* drop the extra reference if sent ok */
415 static int kauditd_thread(void *dummy
)
420 while (!kthread_should_stop()) {
422 * if auditd just started drain the queue of messages already
423 * sent to syslog/printk. remember loss here is ok. we already
424 * called audit_log_lost() if it didn't go out normally. so the
425 * race between the skb_dequeue and the next check for audit_pid
428 * if you ever find kauditd to be too slow we can get a perf win
429 * by doing our own locking and keeping better track if there
430 * are messages in this queue. I don't see the need now, but
431 * in 5 years when I want to play with this again I'll see this
432 * note and still have no friggin idea what i'm thinking today.
434 if (audit_default
&& audit_pid
) {
435 skb
= skb_dequeue(&audit_skb_hold_queue
);
437 while (skb
&& audit_pid
) {
438 kauditd_send_skb(skb
);
439 skb
= skb_dequeue(&audit_skb_hold_queue
);
444 skb
= skb_dequeue(&audit_skb_queue
);
445 wake_up(&audit_backlog_wait
);
448 kauditd_send_skb(skb
);
450 audit_printk_skb(skb
);
452 DECLARE_WAITQUEUE(wait
, current
);
453 set_current_state(TASK_INTERRUPTIBLE
);
454 add_wait_queue(&kauditd_wait
, &wait
);
456 if (!skb_queue_len(&audit_skb_queue
)) {
461 __set_current_state(TASK_RUNNING
);
462 remove_wait_queue(&kauditd_wait
, &wait
);
468 static int audit_prepare_user_tty(pid_t pid
, uid_t loginuid
, u32 sessionid
)
470 struct task_struct
*tsk
;
473 read_lock(&tasklist_lock
);
474 tsk
= find_task_by_vpid(pid
);
480 spin_lock_irq(&tsk
->sighand
->siglock
);
481 if (!tsk
->signal
->audit_tty
)
483 spin_unlock_irq(&tsk
->sighand
->siglock
);
487 tty_audit_push_task(tsk
, loginuid
, sessionid
);
489 read_unlock(&tasklist_lock
);
493 int audit_send_list(void *_dest
)
495 struct audit_netlink_list
*dest
= _dest
;
499 /* wait for parent to finish and send an ACK */
500 mutex_lock(&audit_cmd_mutex
);
501 mutex_unlock(&audit_cmd_mutex
);
503 while ((skb
= __skb_dequeue(&dest
->q
)) != NULL
)
504 netlink_unicast(audit_sock
, skb
, pid
, 0);
511 #ifdef CONFIG_AUDIT_TREE
512 static int prune_tree_thread(void *unused
)
514 mutex_lock(&audit_cmd_mutex
);
516 mutex_unlock(&audit_cmd_mutex
);
520 void audit_schedule_prune(void)
522 kthread_run(prune_tree_thread
, NULL
, "audit_prune_tree");
526 struct sk_buff
*audit_make_reply(int pid
, int seq
, int type
, int done
,
527 int multi
, void *payload
, int size
)
530 struct nlmsghdr
*nlh
;
532 int flags
= multi
? NLM_F_MULTI
: 0;
533 int t
= done
? NLMSG_DONE
: type
;
535 skb
= nlmsg_new(size
, GFP_KERNEL
);
539 nlh
= NLMSG_NEW(skb
, pid
, seq
, t
, size
, flags
);
540 data
= NLMSG_DATA(nlh
);
541 memcpy(data
, payload
, size
);
544 nlmsg_failure
: /* Used by NLMSG_NEW */
550 static int audit_send_reply_thread(void *arg
)
552 struct audit_reply
*reply
= (struct audit_reply
*)arg
;
554 mutex_lock(&audit_cmd_mutex
);
555 mutex_unlock(&audit_cmd_mutex
);
557 /* Ignore failure. It'll only happen if the sender goes away,
558 because our timeout is set to infinite. */
559 netlink_unicast(audit_sock
, reply
->skb
, reply
->pid
, 0);
564 * audit_send_reply - send an audit reply message via netlink
565 * @pid: process id to send reply to
566 * @seq: sequence number
567 * @type: audit message type
568 * @done: done (last) flag
569 * @multi: multi-part message flag
570 * @payload: payload data
571 * @size: payload size
573 * Allocates an skb, builds the netlink message, and sends it to the pid.
574 * No failure notifications.
576 void audit_send_reply(int pid
, int seq
, int type
, int done
, int multi
,
577 void *payload
, int size
)
580 struct task_struct
*tsk
;
581 struct audit_reply
*reply
= kmalloc(sizeof(struct audit_reply
),
587 skb
= audit_make_reply(pid
, seq
, type
, done
, multi
, payload
, size
);
594 tsk
= kthread_run(audit_send_reply_thread
, reply
, "audit_send_reply");
603 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
606 static int audit_netlink_ok(struct sk_buff
*skb
, u16 msg_type
)
613 case AUDIT_LIST_RULES
:
619 case AUDIT_SIGNAL_INFO
:
623 case AUDIT_MAKE_EQUIV
:
624 if (security_netlink_recv(skb
, CAP_AUDIT_CONTROL
))
628 case AUDIT_FIRST_USER_MSG
... AUDIT_LAST_USER_MSG
:
629 case AUDIT_FIRST_USER_MSG2
... AUDIT_LAST_USER_MSG2
:
630 if (security_netlink_recv(skb
, CAP_AUDIT_WRITE
))
633 default: /* bad msg */
640 static int audit_log_common_recv_msg(struct audit_buffer
**ab
, u16 msg_type
,
641 u32 pid
, u32 uid
, uid_t auid
, u32 ses
,
648 if (!audit_enabled
) {
653 *ab
= audit_log_start(NULL
, GFP_KERNEL
, msg_type
);
654 audit_log_format(*ab
, "user pid=%d uid=%u auid=%u ses=%u",
655 pid
, uid
, auid
, ses
);
657 rc
= security_secid_to_secctx(sid
, &ctx
, &len
);
659 audit_log_format(*ab
, " ssid=%u", sid
);
661 audit_log_format(*ab
, " subj=%s", ctx
);
662 security_release_secctx(ctx
, len
);
669 static int audit_receive_msg(struct sk_buff
*skb
, struct nlmsghdr
*nlh
)
671 u32 uid
, pid
, seq
, sid
;
673 struct audit_status
*status_get
, status_set
;
675 struct audit_buffer
*ab
;
676 u16 msg_type
= nlh
->nlmsg_type
;
677 uid_t loginuid
; /* loginuid of sender */
679 struct audit_sig_info
*sig_data
;
683 err
= audit_netlink_ok(skb
, msg_type
);
687 /* As soon as there's any sign of userspace auditd,
688 * start kauditd to talk to it */
690 kauditd_task
= kthread_run(kauditd_thread
, NULL
, "kauditd");
691 if (IS_ERR(kauditd_task
)) {
692 err
= PTR_ERR(kauditd_task
);
697 pid
= NETLINK_CREDS(skb
)->pid
;
698 uid
= NETLINK_CREDS(skb
)->uid
;
699 loginuid
= NETLINK_CB(skb
).loginuid
;
700 sessionid
= NETLINK_CB(skb
).sessionid
;
701 sid
= NETLINK_CB(skb
).sid
;
702 seq
= nlh
->nlmsg_seq
;
703 data
= NLMSG_DATA(nlh
);
707 status_set
.enabled
= audit_enabled
;
708 status_set
.failure
= audit_failure
;
709 status_set
.pid
= audit_pid
;
710 status_set
.rate_limit
= audit_rate_limit
;
711 status_set
.backlog_limit
= audit_backlog_limit
;
712 status_set
.lost
= atomic_read(&audit_lost
);
713 status_set
.backlog
= skb_queue_len(&audit_skb_queue
);
714 audit_send_reply(NETLINK_CB(skb
).pid
, seq
, AUDIT_GET
, 0, 0,
715 &status_set
, sizeof(status_set
));
718 if (nlh
->nlmsg_len
< sizeof(struct audit_status
))
720 status_get
= (struct audit_status
*)data
;
721 if (status_get
->mask
& AUDIT_STATUS_ENABLED
) {
722 err
= audit_set_enabled(status_get
->enabled
,
723 loginuid
, sessionid
, sid
);
727 if (status_get
->mask
& AUDIT_STATUS_FAILURE
) {
728 err
= audit_set_failure(status_get
->failure
,
729 loginuid
, sessionid
, sid
);
733 if (status_get
->mask
& AUDIT_STATUS_PID
) {
734 int new_pid
= status_get
->pid
;
736 if (audit_enabled
!= AUDIT_OFF
)
737 audit_log_config_change("audit_pid", new_pid
,
742 audit_nlk_pid
= NETLINK_CB(skb
).pid
;
744 if (status_get
->mask
& AUDIT_STATUS_RATE_LIMIT
) {
745 err
= audit_set_rate_limit(status_get
->rate_limit
,
746 loginuid
, sessionid
, sid
);
750 if (status_get
->mask
& AUDIT_STATUS_BACKLOG_LIMIT
)
751 err
= audit_set_backlog_limit(status_get
->backlog_limit
,
752 loginuid
, sessionid
, sid
);
755 case AUDIT_FIRST_USER_MSG
... AUDIT_LAST_USER_MSG
:
756 case AUDIT_FIRST_USER_MSG2
... AUDIT_LAST_USER_MSG2
:
757 if (!audit_enabled
&& msg_type
!= AUDIT_USER_AVC
)
760 err
= audit_filter_user(&NETLINK_CB(skb
));
763 if (msg_type
== AUDIT_USER_TTY
) {
764 err
= audit_prepare_user_tty(pid
, loginuid
,
769 audit_log_common_recv_msg(&ab
, msg_type
, pid
, uid
,
770 loginuid
, sessionid
, sid
);
772 if (msg_type
!= AUDIT_USER_TTY
)
773 audit_log_format(ab
, " msg='%.1024s'",
778 audit_log_format(ab
, " msg=");
779 size
= nlmsg_len(nlh
);
781 ((unsigned char *)data
)[size
- 1] == '\0')
783 audit_log_n_untrustedstring(ab
, data
, size
);
785 audit_set_pid(ab
, pid
);
791 if (nlmsg_len(nlh
) < sizeof(struct audit_rule
))
793 if (audit_enabled
== AUDIT_LOCKED
) {
794 audit_log_common_recv_msg(&ab
, AUDIT_CONFIG_CHANGE
, pid
,
795 uid
, loginuid
, sessionid
, sid
);
797 audit_log_format(ab
, " audit_enabled=%d res=0",
804 err
= audit_receive_filter(msg_type
, NETLINK_CB(skb
).pid
,
805 uid
, seq
, data
, nlmsg_len(nlh
),
806 loginuid
, sessionid
, sid
);
810 if (nlmsg_len(nlh
) < sizeof(struct audit_rule_data
))
812 if (audit_enabled
== AUDIT_LOCKED
) {
813 audit_log_common_recv_msg(&ab
, AUDIT_CONFIG_CHANGE
, pid
,
814 uid
, loginuid
, sessionid
, sid
);
816 audit_log_format(ab
, " audit_enabled=%d res=0",
822 case AUDIT_LIST_RULES
:
823 err
= audit_receive_filter(msg_type
, NETLINK_CB(skb
).pid
,
824 uid
, seq
, data
, nlmsg_len(nlh
),
825 loginuid
, sessionid
, sid
);
830 audit_log_common_recv_msg(&ab
, AUDIT_CONFIG_CHANGE
, pid
,
831 uid
, loginuid
, sessionid
, sid
);
833 audit_log_format(ab
, " op=trim res=1");
836 case AUDIT_MAKE_EQUIV
: {
839 size_t msglen
= nlmsg_len(nlh
);
843 if (msglen
< 2 * sizeof(u32
))
845 memcpy(sizes
, bufp
, 2 * sizeof(u32
));
846 bufp
+= 2 * sizeof(u32
);
847 msglen
-= 2 * sizeof(u32
);
848 old
= audit_unpack_string(&bufp
, &msglen
, sizes
[0]);
853 new = audit_unpack_string(&bufp
, &msglen
, sizes
[1]);
859 /* OK, here comes... */
860 err
= audit_tag_tree(old
, new);
862 audit_log_common_recv_msg(&ab
, AUDIT_CONFIG_CHANGE
, pid
,
863 uid
, loginuid
, sessionid
, sid
);
865 audit_log_format(ab
, " op=make_equiv old=");
866 audit_log_untrustedstring(ab
, old
);
867 audit_log_format(ab
, " new=");
868 audit_log_untrustedstring(ab
, new);
869 audit_log_format(ab
, " res=%d", !err
);
875 case AUDIT_SIGNAL_INFO
:
876 err
= security_secid_to_secctx(audit_sig_sid
, &ctx
, &len
);
879 sig_data
= kmalloc(sizeof(*sig_data
) + len
, GFP_KERNEL
);
881 security_release_secctx(ctx
, len
);
884 sig_data
->uid
= audit_sig_uid
;
885 sig_data
->pid
= audit_sig_pid
;
886 memcpy(sig_data
->ctx
, ctx
, len
);
887 security_release_secctx(ctx
, len
);
888 audit_send_reply(NETLINK_CB(skb
).pid
, seq
, AUDIT_SIGNAL_INFO
,
889 0, 0, sig_data
, sizeof(*sig_data
) + len
);
892 case AUDIT_TTY_GET
: {
893 struct audit_tty_status s
;
894 struct task_struct
*tsk
;
896 read_lock(&tasklist_lock
);
897 tsk
= find_task_by_vpid(pid
);
901 spin_lock_irq(&tsk
->sighand
->siglock
);
902 s
.enabled
= tsk
->signal
->audit_tty
!= 0;
903 spin_unlock_irq(&tsk
->sighand
->siglock
);
905 read_unlock(&tasklist_lock
);
906 audit_send_reply(NETLINK_CB(skb
).pid
, seq
, AUDIT_TTY_GET
, 0, 0,
910 case AUDIT_TTY_SET
: {
911 struct audit_tty_status
*s
;
912 struct task_struct
*tsk
;
914 if (nlh
->nlmsg_len
< sizeof(struct audit_tty_status
))
917 if (s
->enabled
!= 0 && s
->enabled
!= 1)
919 read_lock(&tasklist_lock
);
920 tsk
= find_task_by_vpid(pid
);
924 spin_lock_irq(&tsk
->sighand
->siglock
);
925 tsk
->signal
->audit_tty
= s
->enabled
!= 0;
926 spin_unlock_irq(&tsk
->sighand
->siglock
);
928 read_unlock(&tasklist_lock
);
936 return err
< 0 ? err
: 0;
940 * Get message from skb (based on rtnetlink_rcv_skb). Each message is
941 * processed by audit_receive_msg. Malformed skbs with wrong length are
942 * discarded silently.
944 static void audit_receive_skb(struct sk_buff
*skb
)
947 struct nlmsghdr
*nlh
;
950 while (skb
->len
>= NLMSG_SPACE(0)) {
951 nlh
= nlmsg_hdr(skb
);
952 if (nlh
->nlmsg_len
< sizeof(*nlh
) || skb
->len
< nlh
->nlmsg_len
)
954 rlen
= NLMSG_ALIGN(nlh
->nlmsg_len
);
957 if ((err
= audit_receive_msg(skb
, nlh
))) {
958 netlink_ack(skb
, nlh
, err
);
959 } else if (nlh
->nlmsg_flags
& NLM_F_ACK
)
960 netlink_ack(skb
, nlh
, 0);
965 /* Receive messages from netlink socket. */
966 static void audit_receive(struct sk_buff
*skb
)
968 mutex_lock(&audit_cmd_mutex
);
969 audit_receive_skb(skb
);
970 mutex_unlock(&audit_cmd_mutex
);
973 #ifdef CONFIG_AUDITSYSCALL
974 static const struct inotify_operations audit_inotify_ops
= {
975 .handle_event
= audit_handle_ievent
,
976 .destroy_watch
= audit_free_parent
,
980 /* Initialize audit support at boot time. */
981 static int __init
audit_init(void)
985 if (audit_initialized
== AUDIT_DISABLED
)
988 printk(KERN_INFO
"audit: initializing netlink socket (%s)\n",
989 audit_default
? "enabled" : "disabled");
990 audit_sock
= netlink_kernel_create(&init_net
, NETLINK_AUDIT
, 0,
991 audit_receive
, NULL
, THIS_MODULE
);
993 audit_panic("cannot initialize netlink socket");
995 audit_sock
->sk_sndtimeo
= MAX_SCHEDULE_TIMEOUT
;
997 skb_queue_head_init(&audit_skb_queue
);
998 skb_queue_head_init(&audit_skb_hold_queue
);
999 audit_initialized
= AUDIT_INITIALIZED
;
1000 audit_enabled
= audit_default
;
1001 audit_ever_enabled
|= !!audit_default
;
1003 audit_log(NULL
, GFP_KERNEL
, AUDIT_KERNEL
, "initialized");
1005 #ifdef CONFIG_AUDITSYSCALL
1006 audit_ih
= inotify_init(&audit_inotify_ops
);
1007 if (IS_ERR(audit_ih
))
1008 audit_panic("cannot initialize inotify handle");
1011 for (i
= 0; i
< AUDIT_INODE_BUCKETS
; i
++)
1012 INIT_LIST_HEAD(&audit_inode_hash
[i
]);
1016 __initcall(audit_init
);
1018 /* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
1019 static int __init
audit_enable(char *str
)
1021 audit_default
= !!simple_strtol(str
, NULL
, 0);
1023 audit_initialized
= AUDIT_DISABLED
;
1025 printk(KERN_INFO
"audit: %s", audit_default
? "enabled" : "disabled");
1027 if (audit_initialized
== AUDIT_INITIALIZED
) {
1028 audit_enabled
= audit_default
;
1029 audit_ever_enabled
|= !!audit_default
;
1030 } else if (audit_initialized
== AUDIT_UNINITIALIZED
) {
1031 printk(" (after initialization)");
1033 printk(" (until reboot)");
1040 __setup("audit=", audit_enable
);
1042 static void audit_buffer_free(struct audit_buffer
*ab
)
1044 unsigned long flags
;
1052 spin_lock_irqsave(&audit_freelist_lock
, flags
);
1053 if (audit_freelist_count
> AUDIT_MAXFREE
)
1056 audit_freelist_count
++;
1057 list_add(&ab
->list
, &audit_freelist
);
1059 spin_unlock_irqrestore(&audit_freelist_lock
, flags
);
1062 static struct audit_buffer
* audit_buffer_alloc(struct audit_context
*ctx
,
1063 gfp_t gfp_mask
, int type
)
1065 unsigned long flags
;
1066 struct audit_buffer
*ab
= NULL
;
1067 struct nlmsghdr
*nlh
;
1069 spin_lock_irqsave(&audit_freelist_lock
, flags
);
1070 if (!list_empty(&audit_freelist
)) {
1071 ab
= list_entry(audit_freelist
.next
,
1072 struct audit_buffer
, list
);
1073 list_del(&ab
->list
);
1074 --audit_freelist_count
;
1076 spin_unlock_irqrestore(&audit_freelist_lock
, flags
);
1079 ab
= kmalloc(sizeof(*ab
), gfp_mask
);
1085 ab
->gfp_mask
= gfp_mask
;
1087 ab
->skb
= nlmsg_new(AUDIT_BUFSIZ
, gfp_mask
);
1091 nlh
= NLMSG_NEW(ab
->skb
, 0, 0, type
, 0, 0);
1095 nlmsg_failure
: /* Used by NLMSG_NEW */
1099 audit_buffer_free(ab
);
1104 * audit_serial - compute a serial number for the audit record
1106 * Compute a serial number for the audit record. Audit records are
1107 * written to user-space as soon as they are generated, so a complete
1108 * audit record may be written in several pieces. The timestamp of the
1109 * record and this serial number are used by the user-space tools to
1110 * determine which pieces belong to the same audit record. The
1111 * (timestamp,serial) tuple is unique for each syscall and is live from
1112 * syscall entry to syscall exit.
1114 * NOTE: Another possibility is to store the formatted records off the
1115 * audit context (for those records that have a context), and emit them
1116 * all at syscall exit. However, this could delay the reporting of
1117 * significant errors until syscall exit (or never, if the system
1120 unsigned int audit_serial(void)
1122 static DEFINE_SPINLOCK(serial_lock
);
1123 static unsigned int serial
= 0;
1125 unsigned long flags
;
1128 spin_lock_irqsave(&serial_lock
, flags
);
1131 } while (unlikely(!ret
));
1132 spin_unlock_irqrestore(&serial_lock
, flags
);
1137 static inline void audit_get_stamp(struct audit_context
*ctx
,
1138 struct timespec
*t
, unsigned int *serial
)
1140 if (!ctx
|| !auditsc_get_stamp(ctx
, t
, serial
)) {
1142 *serial
= audit_serial();
1146 /* Obtain an audit buffer. This routine does locking to obtain the
1147 * audit buffer, but then no locking is required for calls to
1148 * audit_log_*format. If the tsk is a task that is currently in a
1149 * syscall, then the syscall is marked as auditable and an audit record
1150 * will be written at syscall exit. If there is no associated task, tsk
1151 * should be NULL. */
1154 * audit_log_start - obtain an audit buffer
1155 * @ctx: audit_context (may be NULL)
1156 * @gfp_mask: type of allocation
1157 * @type: audit message type
1159 * Returns audit_buffer pointer on success or NULL on error.
1161 * Obtain an audit buffer. This routine does locking to obtain the
1162 * audit buffer, but then no locking is required for calls to
1163 * audit_log_*format. If the task (ctx) is a task that is currently in a
1164 * syscall, then the syscall is marked as auditable and an audit record
1165 * will be written at syscall exit. If there is no associated task, then
1166 * task context (ctx) should be NULL.
1168 struct audit_buffer
*audit_log_start(struct audit_context
*ctx
, gfp_t gfp_mask
,
1171 struct audit_buffer
*ab
= NULL
;
1173 unsigned int uninitialized_var(serial
);
1175 unsigned long timeout_start
= jiffies
;
1177 if (audit_initialized
!= AUDIT_INITIALIZED
)
1180 if (unlikely(audit_filter_type(type
)))
1183 if (gfp_mask
& __GFP_WAIT
)
1186 reserve
= 5; /* Allow atomic callers to go up to five
1187 entries over the normal backlog limit */
1189 while (audit_backlog_limit
1190 && skb_queue_len(&audit_skb_queue
) > audit_backlog_limit
+ reserve
) {
1191 if (gfp_mask
& __GFP_WAIT
&& audit_backlog_wait_time
1192 && time_before(jiffies
, timeout_start
+ audit_backlog_wait_time
)) {
1194 /* Wait for auditd to drain the queue a little */
1195 DECLARE_WAITQUEUE(wait
, current
);
1196 set_current_state(TASK_INTERRUPTIBLE
);
1197 add_wait_queue(&audit_backlog_wait
, &wait
);
1199 if (audit_backlog_limit
&&
1200 skb_queue_len(&audit_skb_queue
) > audit_backlog_limit
)
1201 schedule_timeout(timeout_start
+ audit_backlog_wait_time
- jiffies
);
1203 __set_current_state(TASK_RUNNING
);
1204 remove_wait_queue(&audit_backlog_wait
, &wait
);
1207 if (audit_rate_check() && printk_ratelimit())
1209 "audit: audit_backlog=%d > "
1210 "audit_backlog_limit=%d\n",
1211 skb_queue_len(&audit_skb_queue
),
1212 audit_backlog_limit
);
1213 audit_log_lost("backlog limit exceeded");
1214 audit_backlog_wait_time
= audit_backlog_wait_overflow
;
1215 wake_up(&audit_backlog_wait
);
1219 ab
= audit_buffer_alloc(ctx
, gfp_mask
, type
);
1221 audit_log_lost("out of memory in audit_log_start");
1225 audit_get_stamp(ab
->ctx
, &t
, &serial
);
1227 audit_log_format(ab
, "audit(%lu.%03lu:%u): ",
1228 t
.tv_sec
, t
.tv_nsec
/1000000, serial
);
1233 * audit_expand - expand skb in the audit buffer
1235 * @extra: space to add at tail of the skb
1237 * Returns 0 (no space) on failed expansion, or available space if
1240 static inline int audit_expand(struct audit_buffer
*ab
, int extra
)
1242 struct sk_buff
*skb
= ab
->skb
;
1243 int oldtail
= skb_tailroom(skb
);
1244 int ret
= pskb_expand_head(skb
, 0, extra
, ab
->gfp_mask
);
1245 int newtail
= skb_tailroom(skb
);
1248 audit_log_lost("out of memory in audit_expand");
1252 skb
->truesize
+= newtail
- oldtail
;
1257 * Format an audit message into the audit buffer. If there isn't enough
1258 * room in the audit buffer, more room will be allocated and vsnprint
1259 * will be called a second time. Currently, we assume that a printk
1260 * can't format message larger than 1024 bytes, so we don't either.
1262 static void audit_log_vformat(struct audit_buffer
*ab
, const char *fmt
,
1266 struct sk_buff
*skb
;
1274 avail
= skb_tailroom(skb
);
1276 avail
= audit_expand(ab
, AUDIT_BUFSIZ
);
1280 va_copy(args2
, args
);
1281 len
= vsnprintf(skb_tail_pointer(skb
), avail
, fmt
, args
);
1283 /* The printk buffer is 1024 bytes long, so if we get
1284 * here and AUDIT_BUFSIZ is at least 1024, then we can
1285 * log everything that printk could have logged. */
1286 avail
= audit_expand(ab
,
1287 max_t(unsigned, AUDIT_BUFSIZ
, 1+len
-avail
));
1290 len
= vsnprintf(skb_tail_pointer(skb
), avail
, fmt
, args2
);
1300 * audit_log_format - format a message into the audit buffer.
1302 * @fmt: format string
1303 * @...: optional parameters matching @fmt string
1305 * All the work is done in audit_log_vformat.
1307 void audit_log_format(struct audit_buffer
*ab
, const char *fmt
, ...)
1313 va_start(args
, fmt
);
1314 audit_log_vformat(ab
, fmt
, args
);
1319 * audit_log_hex - convert a buffer to hex and append it to the audit skb
1320 * @ab: the audit_buffer
1321 * @buf: buffer to convert to hex
1322 * @len: length of @buf to be converted
1324 * No return value; failure to expand is silently ignored.
1326 * This function will take the passed buf and convert it into a string of
1327 * ascii hex digits. The new string is placed onto the skb.
1329 void audit_log_n_hex(struct audit_buffer
*ab
, const unsigned char *buf
,
1332 int i
, avail
, new_len
;
1334 struct sk_buff
*skb
;
1335 static const unsigned char *hex
= "0123456789ABCDEF";
1342 avail
= skb_tailroom(skb
);
1344 if (new_len
>= avail
) {
1345 /* Round the buffer request up to the next multiple */
1346 new_len
= AUDIT_BUFSIZ
*(((new_len
-avail
)/AUDIT_BUFSIZ
) + 1);
1347 avail
= audit_expand(ab
, new_len
);
1352 ptr
= skb_tail_pointer(skb
);
1353 for (i
=0; i
<len
; i
++) {
1354 *ptr
++ = hex
[(buf
[i
] & 0xF0)>>4]; /* Upper nibble */
1355 *ptr
++ = hex
[buf
[i
] & 0x0F]; /* Lower nibble */
1358 skb_put(skb
, len
<< 1); /* new string is twice the old string */
1362 * Format a string of no more than slen characters into the audit buffer,
1363 * enclosed in quote marks.
1365 void audit_log_n_string(struct audit_buffer
*ab
, const char *string
,
1370 struct sk_buff
*skb
;
1377 avail
= skb_tailroom(skb
);
1378 new_len
= slen
+ 3; /* enclosing quotes + null terminator */
1379 if (new_len
> avail
) {
1380 avail
= audit_expand(ab
, new_len
);
1384 ptr
= skb_tail_pointer(skb
);
1386 memcpy(ptr
, string
, slen
);
1390 skb_put(skb
, slen
+ 2); /* don't include null terminator */
1394 * audit_string_contains_control - does a string need to be logged in hex
1395 * @string: string to be checked
1396 * @len: max length of the string to check
1398 int audit_string_contains_control(const char *string
, size_t len
)
1400 const unsigned char *p
;
1401 for (p
= string
; p
< (const unsigned char *)string
+ len
; p
++) {
1402 if (*p
== '"' || *p
< 0x21 || *p
> 0x7e)
1409 * audit_log_n_untrustedstring - log a string that may contain random characters
1411 * @len: length of string (not including trailing null)
1412 * @string: string to be logged
1414 * This code will escape a string that is passed to it if the string
1415 * contains a control character, unprintable character, double quote mark,
1416 * or a space. Unescaped strings will start and end with a double quote mark.
1417 * Strings that are escaped are printed in hex (2 digits per char).
1419 * The caller specifies the number of characters in the string to log, which may
1420 * or may not be the entire string.
1422 void audit_log_n_untrustedstring(struct audit_buffer
*ab
, const char *string
,
1425 if (audit_string_contains_control(string
, len
))
1426 audit_log_n_hex(ab
, string
, len
);
1428 audit_log_n_string(ab
, string
, len
);
1432 * audit_log_untrustedstring - log a string that may contain random characters
1434 * @string: string to be logged
1436 * Same as audit_log_n_untrustedstring(), except that strlen is used to
1437 * determine string length.
1439 void audit_log_untrustedstring(struct audit_buffer
*ab
, const char *string
)
1441 audit_log_n_untrustedstring(ab
, string
, strlen(string
));
1444 /* This is a helper-function to print the escaped d_path */
1445 void audit_log_d_path(struct audit_buffer
*ab
, const char *prefix
,
1451 audit_log_format(ab
, " %s", prefix
);
1453 /* We will allow 11 spaces for ' (deleted)' to be appended */
1454 pathname
= kmalloc(PATH_MAX
+11, ab
->gfp_mask
);
1456 audit_log_string(ab
, "<no_memory>");
1459 p
= d_path(path
, pathname
, PATH_MAX
+11);
1460 if (IS_ERR(p
)) { /* Should never happen since we send PATH_MAX */
1461 /* FIXME: can we save some information here? */
1462 audit_log_string(ab
, "<too_long>");
1464 audit_log_untrustedstring(ab
, p
);
1469 * audit_log_end - end one audit record
1470 * @ab: the audit_buffer
1472 * The netlink_* functions cannot be called inside an irq context, so
1473 * the audit buffer is placed on a queue and a tasklet is scheduled to
1474 * remove them from the queue outside the irq context. May be called in
1477 void audit_log_end(struct audit_buffer
*ab
)
1481 if (!audit_rate_check()) {
1482 audit_log_lost("rate limit exceeded");
1484 struct nlmsghdr
*nlh
= nlmsg_hdr(ab
->skb
);
1485 nlh
->nlmsg_len
= ab
->skb
->len
- NLMSG_SPACE(0);
1488 skb_queue_tail(&audit_skb_queue
, ab
->skb
);
1489 wake_up_interruptible(&kauditd_wait
);
1491 audit_printk_skb(ab
->skb
);
1495 audit_buffer_free(ab
);
1499 * audit_log - Log an audit record
1500 * @ctx: audit context
1501 * @gfp_mask: type of allocation
1502 * @type: audit message type
1503 * @fmt: format string to use
1504 * @...: variable parameters matching the format string
1506 * This is a convenience function that calls audit_log_start,
1507 * audit_log_vformat, and audit_log_end. It may be called
1510 void audit_log(struct audit_context
*ctx
, gfp_t gfp_mask
, int type
,
1511 const char *fmt
, ...)
1513 struct audit_buffer
*ab
;
1516 ab
= audit_log_start(ctx
, gfp_mask
, type
);
1518 va_start(args
, fmt
);
1519 audit_log_vformat(ab
, fmt
, args
);
1525 EXPORT_SYMBOL(audit_log_start
);
1526 EXPORT_SYMBOL(audit_log_end
);
1527 EXPORT_SYMBOL(audit_log_format
);
1528 EXPORT_SYMBOL(audit_log
);