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 <linux/atomic.h>
48 #include <linux/export.h>
49 #include <linux/slab.h>
50 #include <linux/err.h>
51 #include <linux/kthread.h>
53 #include <linux/audit.h>
56 #include <net/netlink.h>
57 #include <linux/skbuff.h>
58 #ifdef CONFIG_SECURITY
59 #include <linux/security.h>
61 #include <linux/netlink.h>
62 #include <linux/freezer.h>
63 #include <linux/tty.h>
64 #include <linux/pid_namespace.h>
68 /* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
69 * (Initialization happens after skb_init is called.) */
70 #define AUDIT_DISABLED -1
71 #define AUDIT_UNINITIALIZED 0
72 #define AUDIT_INITIALIZED 1
73 static int audit_initialized
;
77 #define AUDIT_LOCKED 2
79 int audit_ever_enabled
;
81 EXPORT_SYMBOL_GPL(audit_enabled
);
83 /* Default state when kernel boots without any parameters. */
84 static int audit_default
;
86 /* If auditing cannot proceed, audit_failure selects what happens. */
87 static int audit_failure
= AUDIT_FAIL_PRINTK
;
90 * If audit records are to be written to the netlink socket, audit_pid
91 * contains the pid of the auditd process and audit_nlk_pid contains
92 * the pid to use to send netlink messages to that process.
95 static int audit_nlk_pid
;
97 /* If audit_rate_limit is non-zero, limit the rate of sending audit records
98 * to that number per second. This prevents DoS attacks, but results in
99 * audit records being dropped. */
100 static int audit_rate_limit
;
102 /* Number of outstanding audit_buffers allowed. */
103 static int audit_backlog_limit
= 64;
104 static int audit_backlog_wait_time
= 60 * HZ
;
105 static int audit_backlog_wait_overflow
= 0;
107 /* The identity of the user shutting down the audit system. */
108 uid_t audit_sig_uid
= -1;
109 pid_t audit_sig_pid
= -1;
110 u32 audit_sig_sid
= 0;
112 /* Records can be lost in several ways:
113 0) [suppressed in audit_alloc]
114 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
115 2) out of memory in audit_log_move [alloc_skb]
116 3) suppressed due to audit_rate_limit
117 4) suppressed due to audit_backlog_limit
119 static atomic_t audit_lost
= ATOMIC_INIT(0);
121 /* The netlink socket. */
122 static struct sock
*audit_sock
;
124 /* Hash for inode-based rules */
125 struct list_head audit_inode_hash
[AUDIT_INODE_BUCKETS
];
127 /* The audit_freelist is a list of pre-allocated audit buffers (if more
128 * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
129 * being placed on the freelist). */
130 static DEFINE_SPINLOCK(audit_freelist_lock
);
131 static int audit_freelist_count
;
132 static LIST_HEAD(audit_freelist
);
134 static struct sk_buff_head audit_skb_queue
;
135 /* queue of skbs to send to auditd when/if it comes back */
136 static struct sk_buff_head audit_skb_hold_queue
;
137 static struct task_struct
*kauditd_task
;
138 static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait
);
139 static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait
);
141 /* Serialize requests from userspace. */
142 DEFINE_MUTEX(audit_cmd_mutex
);
144 /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
145 * audit records. Since printk uses a 1024 byte buffer, this buffer
146 * should be at least that large. */
147 #define AUDIT_BUFSIZ 1024
149 /* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the
150 * audit_freelist. Doing so eliminates many kmalloc/kfree calls. */
151 #define AUDIT_MAXFREE (2*NR_CPUS)
153 /* The audit_buffer is used when formatting an audit record. The caller
154 * locks briefly to get the record off the freelist or to allocate the
155 * buffer, and locks briefly to send the buffer to the netlink layer or
156 * to place it on a transmit queue. Multiple audit_buffers can be in
157 * use simultaneously. */
158 struct audit_buffer
{
159 struct list_head list
;
160 struct sk_buff
*skb
; /* formatted skb ready to send */
161 struct audit_context
*ctx
; /* NULL or associated context */
170 static void audit_set_pid(struct audit_buffer
*ab
, pid_t pid
)
173 struct nlmsghdr
*nlh
= nlmsg_hdr(ab
->skb
);
174 nlh
->nlmsg_pid
= pid
;
178 void audit_panic(const char *message
)
180 switch (audit_failure
)
182 case AUDIT_FAIL_SILENT
:
184 case AUDIT_FAIL_PRINTK
:
185 if (printk_ratelimit())
186 printk(KERN_ERR
"audit: %s\n", message
);
188 case AUDIT_FAIL_PANIC
:
189 /* test audit_pid since printk is always losey, why bother? */
191 panic("audit: %s\n", message
);
196 static inline int audit_rate_check(void)
198 static unsigned long last_check
= 0;
199 static int messages
= 0;
200 static DEFINE_SPINLOCK(lock
);
203 unsigned long elapsed
;
206 if (!audit_rate_limit
) return 1;
208 spin_lock_irqsave(&lock
, flags
);
209 if (++messages
< audit_rate_limit
) {
213 elapsed
= now
- last_check
;
220 spin_unlock_irqrestore(&lock
, flags
);
226 * audit_log_lost - conditionally log lost audit message event
227 * @message: the message stating reason for lost audit message
229 * Emit at least 1 message per second, even if audit_rate_check is
231 * Always increment the lost messages counter.
233 void audit_log_lost(const char *message
)
235 static unsigned long last_msg
= 0;
236 static DEFINE_SPINLOCK(lock
);
241 atomic_inc(&audit_lost
);
243 print
= (audit_failure
== AUDIT_FAIL_PANIC
|| !audit_rate_limit
);
246 spin_lock_irqsave(&lock
, flags
);
248 if (now
- last_msg
> HZ
) {
252 spin_unlock_irqrestore(&lock
, flags
);
256 if (printk_ratelimit())
258 "audit: audit_lost=%d audit_rate_limit=%d "
259 "audit_backlog_limit=%d\n",
260 atomic_read(&audit_lost
),
262 audit_backlog_limit
);
263 audit_panic(message
);
267 static int audit_log_config_change(char *function_name
, int new, int old
,
268 uid_t loginuid
, u32 sessionid
, u32 sid
,
271 struct audit_buffer
*ab
;
274 ab
= audit_log_start(NULL
, GFP_KERNEL
, AUDIT_CONFIG_CHANGE
);
275 audit_log_format(ab
, "%s=%d old=%d auid=%u ses=%u", function_name
, new,
276 old
, loginuid
, sessionid
);
281 rc
= security_secid_to_secctx(sid
, &ctx
, &len
);
283 audit_log_format(ab
, " sid=%u", sid
);
284 allow_changes
= 0; /* Something weird, deny request */
286 audit_log_format(ab
, " subj=%s", ctx
);
287 security_release_secctx(ctx
, len
);
290 audit_log_format(ab
, " res=%d", allow_changes
);
295 static int audit_do_config_change(char *function_name
, int *to_change
,
296 int new, uid_t loginuid
, u32 sessionid
,
299 int allow_changes
, rc
= 0, old
= *to_change
;
301 /* check if we are locked */
302 if (audit_enabled
== AUDIT_LOCKED
)
307 if (audit_enabled
!= AUDIT_OFF
) {
308 rc
= audit_log_config_change(function_name
, new, old
, loginuid
,
309 sessionid
, sid
, allow_changes
);
314 /* If we are allowed, make the change */
315 if (allow_changes
== 1)
317 /* Not allowed, update reason */
323 static int audit_set_rate_limit(int limit
, uid_t loginuid
, u32 sessionid
,
326 return audit_do_config_change("audit_rate_limit", &audit_rate_limit
,
327 limit
, loginuid
, sessionid
, sid
);
330 static int audit_set_backlog_limit(int limit
, uid_t loginuid
, u32 sessionid
,
333 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit
,
334 limit
, loginuid
, sessionid
, sid
);
337 static int audit_set_enabled(int state
, uid_t loginuid
, u32 sessionid
, u32 sid
)
340 if (state
< AUDIT_OFF
|| state
> AUDIT_LOCKED
)
343 rc
= audit_do_config_change("audit_enabled", &audit_enabled
, state
,
344 loginuid
, sessionid
, sid
);
347 audit_ever_enabled
|= !!state
;
352 static int audit_set_failure(int state
, uid_t loginuid
, u32 sessionid
, u32 sid
)
354 if (state
!= AUDIT_FAIL_SILENT
355 && state
!= AUDIT_FAIL_PRINTK
356 && state
!= AUDIT_FAIL_PANIC
)
359 return audit_do_config_change("audit_failure", &audit_failure
, state
,
360 loginuid
, sessionid
, sid
);
364 * Queue skbs to be sent to auditd when/if it comes back. These skbs should
365 * already have been sent via prink/syslog and so if these messages are dropped
366 * it is not a huge concern since we already passed the audit_log_lost()
367 * notification and stuff. This is just nice to get audit messages during
368 * boot before auditd is running or messages generated while auditd is stopped.
369 * This only holds messages is audit_default is set, aka booting with audit=1
370 * or building your kernel that way.
372 static void audit_hold_skb(struct sk_buff
*skb
)
375 skb_queue_len(&audit_skb_hold_queue
) < audit_backlog_limit
)
376 skb_queue_tail(&audit_skb_hold_queue
, skb
);
382 * For one reason or another this nlh isn't getting delivered to the userspace
383 * audit daemon, just send it to printk.
385 static void audit_printk_skb(struct sk_buff
*skb
)
387 struct nlmsghdr
*nlh
= nlmsg_hdr(skb
);
388 char *data
= nlmsg_data(nlh
);
390 if (nlh
->nlmsg_type
!= AUDIT_EOE
) {
391 if (printk_ratelimit())
392 printk(KERN_NOTICE
"type=%d %s\n", nlh
->nlmsg_type
, data
);
394 audit_log_lost("printk limit exceeded\n");
400 static void kauditd_send_skb(struct sk_buff
*skb
)
403 /* take a reference in case we can't send it and we want to hold it */
405 err
= netlink_unicast(audit_sock
, skb
, audit_nlk_pid
, 0);
407 BUG_ON(err
!= -ECONNREFUSED
); /* Shouldn't happen */
408 printk(KERN_ERR
"audit: *NO* daemon at audit_pid=%d\n", audit_pid
);
409 audit_log_lost("auditd disappeared\n");
411 /* we might get lucky and get this in the next auditd */
414 /* drop the extra reference if sent ok */
418 static int kauditd_thread(void *dummy
)
423 while (!kthread_should_stop()) {
425 * if auditd just started drain the queue of messages already
426 * sent to syslog/printk. remember loss here is ok. we already
427 * called audit_log_lost() if it didn't go out normally. so the
428 * race between the skb_dequeue and the next check for audit_pid
431 * if you ever find kauditd to be too slow we can get a perf win
432 * by doing our own locking and keeping better track if there
433 * are messages in this queue. I don't see the need now, but
434 * in 5 years when I want to play with this again I'll see this
435 * note and still have no friggin idea what i'm thinking today.
437 if (audit_default
&& audit_pid
) {
438 skb
= skb_dequeue(&audit_skb_hold_queue
);
440 while (skb
&& audit_pid
) {
441 kauditd_send_skb(skb
);
442 skb
= skb_dequeue(&audit_skb_hold_queue
);
447 skb
= skb_dequeue(&audit_skb_queue
);
448 wake_up(&audit_backlog_wait
);
451 kauditd_send_skb(skb
);
453 audit_printk_skb(skb
);
455 DECLARE_WAITQUEUE(wait
, current
);
456 set_current_state(TASK_INTERRUPTIBLE
);
457 add_wait_queue(&kauditd_wait
, &wait
);
459 if (!skb_queue_len(&audit_skb_queue
)) {
464 __set_current_state(TASK_RUNNING
);
465 remove_wait_queue(&kauditd_wait
, &wait
);
471 int audit_send_list(void *_dest
)
473 struct audit_netlink_list
*dest
= _dest
;
477 /* wait for parent to finish and send an ACK */
478 mutex_lock(&audit_cmd_mutex
);
479 mutex_unlock(&audit_cmd_mutex
);
481 while ((skb
= __skb_dequeue(&dest
->q
)) != NULL
)
482 netlink_unicast(audit_sock
, skb
, pid
, 0);
489 struct sk_buff
*audit_make_reply(int pid
, int seq
, int type
, int done
,
490 int multi
, const void *payload
, int size
)
493 struct nlmsghdr
*nlh
;
495 int flags
= multi
? NLM_F_MULTI
: 0;
496 int t
= done
? NLMSG_DONE
: type
;
498 skb
= nlmsg_new(size
, GFP_KERNEL
);
502 nlh
= nlmsg_put(skb
, pid
, seq
, t
, size
, flags
);
505 data
= nlmsg_data(nlh
);
506 memcpy(data
, payload
, size
);
514 static int audit_send_reply_thread(void *arg
)
516 struct audit_reply
*reply
= (struct audit_reply
*)arg
;
518 mutex_lock(&audit_cmd_mutex
);
519 mutex_unlock(&audit_cmd_mutex
);
521 /* Ignore failure. It'll only happen if the sender goes away,
522 because our timeout is set to infinite. */
523 netlink_unicast(audit_sock
, reply
->skb
, reply
->pid
, 0);
528 * audit_send_reply - send an audit reply message via netlink
529 * @pid: process id to send reply to
530 * @seq: sequence number
531 * @type: audit message type
532 * @done: done (last) flag
533 * @multi: multi-part message flag
534 * @payload: payload data
535 * @size: payload size
537 * Allocates an skb, builds the netlink message, and sends it to the pid.
538 * No failure notifications.
540 static void audit_send_reply(int pid
, int seq
, int type
, int done
, int multi
,
541 const void *payload
, int size
)
544 struct task_struct
*tsk
;
545 struct audit_reply
*reply
= kmalloc(sizeof(struct audit_reply
),
551 skb
= audit_make_reply(pid
, seq
, type
, done
, multi
, payload
, size
);
558 tsk
= kthread_run(audit_send_reply_thread
, reply
, "audit_send_reply");
567 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
570 static int audit_netlink_ok(struct sk_buff
*skb
, u16 msg_type
)
574 /* Only support the initial namespaces for now. */
575 if ((current_user_ns() != &init_user_ns
) ||
576 (task_active_pid_ns(current
) != &init_pid_ns
))
582 case AUDIT_LIST_RULES
:
588 case AUDIT_SIGNAL_INFO
:
592 case AUDIT_MAKE_EQUIV
:
593 if (!capable(CAP_AUDIT_CONTROL
))
597 case AUDIT_FIRST_USER_MSG
... AUDIT_LAST_USER_MSG
:
598 case AUDIT_FIRST_USER_MSG2
... AUDIT_LAST_USER_MSG2
:
599 if (!capable(CAP_AUDIT_WRITE
))
602 default: /* bad msg */
609 static int audit_log_common_recv_msg(struct audit_buffer
**ab
, u16 msg_type
,
610 u32 pid
, u32 uid
, uid_t auid
, u32 ses
,
617 if (!audit_enabled
) {
622 *ab
= audit_log_start(NULL
, GFP_KERNEL
, msg_type
);
623 audit_log_format(*ab
, "pid=%d uid=%u auid=%u ses=%u",
624 pid
, uid
, auid
, ses
);
626 rc
= security_secid_to_secctx(sid
, &ctx
, &len
);
628 audit_log_format(*ab
, " ssid=%u", sid
);
630 audit_log_format(*ab
, " subj=%s", ctx
);
631 security_release_secctx(ctx
, len
);
638 static int audit_receive_msg(struct sk_buff
*skb
, struct nlmsghdr
*nlh
)
640 u32 uid
, pid
, seq
, sid
;
642 struct audit_status
*status_get
, status_set
;
644 struct audit_buffer
*ab
;
645 u16 msg_type
= nlh
->nlmsg_type
;
646 uid_t loginuid
; /* loginuid of sender */
648 struct audit_sig_info
*sig_data
;
652 err
= audit_netlink_ok(skb
, msg_type
);
656 /* As soon as there's any sign of userspace auditd,
657 * start kauditd to talk to it */
659 kauditd_task
= kthread_run(kauditd_thread
, NULL
, "kauditd");
660 if (IS_ERR(kauditd_task
)) {
661 err
= PTR_ERR(kauditd_task
);
666 pid
= NETLINK_CREDS(skb
)->pid
;
667 uid
= NETLINK_CREDS(skb
)->uid
;
668 loginuid
= audit_get_loginuid(current
);
669 sessionid
= audit_get_sessionid(current
);
670 security_task_getsecid(current
, &sid
);
671 seq
= nlh
->nlmsg_seq
;
672 data
= nlmsg_data(nlh
);
676 status_set
.enabled
= audit_enabled
;
677 status_set
.failure
= audit_failure
;
678 status_set
.pid
= audit_pid
;
679 status_set
.rate_limit
= audit_rate_limit
;
680 status_set
.backlog_limit
= audit_backlog_limit
;
681 status_set
.lost
= atomic_read(&audit_lost
);
682 status_set
.backlog
= skb_queue_len(&audit_skb_queue
);
683 audit_send_reply(NETLINK_CB(skb
).pid
, seq
, AUDIT_GET
, 0, 0,
684 &status_set
, sizeof(status_set
));
687 if (nlh
->nlmsg_len
< sizeof(struct audit_status
))
689 status_get
= (struct audit_status
*)data
;
690 if (status_get
->mask
& AUDIT_STATUS_ENABLED
) {
691 err
= audit_set_enabled(status_get
->enabled
,
692 loginuid
, sessionid
, sid
);
696 if (status_get
->mask
& AUDIT_STATUS_FAILURE
) {
697 err
= audit_set_failure(status_get
->failure
,
698 loginuid
, sessionid
, sid
);
702 if (status_get
->mask
& AUDIT_STATUS_PID
) {
703 int new_pid
= status_get
->pid
;
705 if (audit_enabled
!= AUDIT_OFF
)
706 audit_log_config_change("audit_pid", new_pid
,
711 audit_nlk_pid
= NETLINK_CB(skb
).pid
;
713 if (status_get
->mask
& AUDIT_STATUS_RATE_LIMIT
) {
714 err
= audit_set_rate_limit(status_get
->rate_limit
,
715 loginuid
, sessionid
, sid
);
719 if (status_get
->mask
& AUDIT_STATUS_BACKLOG_LIMIT
)
720 err
= audit_set_backlog_limit(status_get
->backlog_limit
,
721 loginuid
, sessionid
, sid
);
724 case AUDIT_FIRST_USER_MSG
... AUDIT_LAST_USER_MSG
:
725 case AUDIT_FIRST_USER_MSG2
... AUDIT_LAST_USER_MSG2
:
726 if (!audit_enabled
&& msg_type
!= AUDIT_USER_AVC
)
729 err
= audit_filter_user();
732 if (msg_type
== AUDIT_USER_TTY
) {
733 err
= tty_audit_push_task(current
, loginuid
,
738 audit_log_common_recv_msg(&ab
, msg_type
, pid
, uid
,
739 loginuid
, sessionid
, sid
);
741 if (msg_type
!= AUDIT_USER_TTY
)
742 audit_log_format(ab
, " msg='%.1024s'",
747 audit_log_format(ab
, " msg=");
748 size
= nlmsg_len(nlh
);
750 ((unsigned char *)data
)[size
- 1] == '\0')
752 audit_log_n_untrustedstring(ab
, data
, size
);
754 audit_set_pid(ab
, pid
);
760 if (nlmsg_len(nlh
) < sizeof(struct audit_rule
))
762 if (audit_enabled
== AUDIT_LOCKED
) {
763 audit_log_common_recv_msg(&ab
, AUDIT_CONFIG_CHANGE
, pid
,
764 uid
, loginuid
, sessionid
, sid
);
766 audit_log_format(ab
, " audit_enabled=%d res=0",
773 err
= audit_receive_filter(msg_type
, NETLINK_CB(skb
).pid
,
774 uid
, seq
, data
, nlmsg_len(nlh
),
775 loginuid
, sessionid
, sid
);
779 if (nlmsg_len(nlh
) < sizeof(struct audit_rule_data
))
781 if (audit_enabled
== AUDIT_LOCKED
) {
782 audit_log_common_recv_msg(&ab
, AUDIT_CONFIG_CHANGE
, pid
,
783 uid
, loginuid
, sessionid
, sid
);
785 audit_log_format(ab
, " audit_enabled=%d res=0",
791 case AUDIT_LIST_RULES
:
792 err
= audit_receive_filter(msg_type
, NETLINK_CB(skb
).pid
,
793 uid
, seq
, data
, nlmsg_len(nlh
),
794 loginuid
, sessionid
, sid
);
799 audit_log_common_recv_msg(&ab
, AUDIT_CONFIG_CHANGE
, pid
,
800 uid
, loginuid
, sessionid
, sid
);
802 audit_log_format(ab
, " op=trim res=1");
805 case AUDIT_MAKE_EQUIV
: {
808 size_t msglen
= nlmsg_len(nlh
);
812 if (msglen
< 2 * sizeof(u32
))
814 memcpy(sizes
, bufp
, 2 * sizeof(u32
));
815 bufp
+= 2 * sizeof(u32
);
816 msglen
-= 2 * sizeof(u32
);
817 old
= audit_unpack_string(&bufp
, &msglen
, sizes
[0]);
822 new = audit_unpack_string(&bufp
, &msglen
, sizes
[1]);
828 /* OK, here comes... */
829 err
= audit_tag_tree(old
, new);
831 audit_log_common_recv_msg(&ab
, AUDIT_CONFIG_CHANGE
, pid
,
832 uid
, loginuid
, sessionid
, sid
);
834 audit_log_format(ab
, " op=make_equiv old=");
835 audit_log_untrustedstring(ab
, old
);
836 audit_log_format(ab
, " new=");
837 audit_log_untrustedstring(ab
, new);
838 audit_log_format(ab
, " res=%d", !err
);
844 case AUDIT_SIGNAL_INFO
:
847 err
= security_secid_to_secctx(audit_sig_sid
, &ctx
, &len
);
851 sig_data
= kmalloc(sizeof(*sig_data
) + len
, GFP_KERNEL
);
854 security_release_secctx(ctx
, len
);
857 sig_data
->uid
= audit_sig_uid
;
858 sig_data
->pid
= audit_sig_pid
;
860 memcpy(sig_data
->ctx
, ctx
, len
);
861 security_release_secctx(ctx
, len
);
863 audit_send_reply(NETLINK_CB(skb
).pid
, seq
, AUDIT_SIGNAL_INFO
,
864 0, 0, sig_data
, sizeof(*sig_data
) + len
);
867 case AUDIT_TTY_GET
: {
868 struct audit_tty_status s
;
869 struct task_struct
*tsk
= current
;
871 spin_lock_irq(&tsk
->sighand
->siglock
);
872 s
.enabled
= tsk
->signal
->audit_tty
!= 0;
873 spin_unlock_irq(&tsk
->sighand
->siglock
);
875 audit_send_reply(NETLINK_CB(skb
).pid
, seq
,
876 AUDIT_TTY_GET
, 0, 0, &s
, sizeof(s
));
879 case AUDIT_TTY_SET
: {
880 struct audit_tty_status
*s
;
881 struct task_struct
*tsk
= current
;
883 if (nlh
->nlmsg_len
< sizeof(struct audit_tty_status
))
886 if (s
->enabled
!= 0 && s
->enabled
!= 1)
889 spin_lock_irq(&tsk
->sighand
->siglock
);
890 tsk
->signal
->audit_tty
= s
->enabled
!= 0;
891 spin_unlock_irq(&tsk
->sighand
->siglock
);
899 return err
< 0 ? err
: 0;
903 * Get message from skb. Each message is processed by audit_receive_msg.
904 * Malformed skbs with wrong length are discarded silently.
906 static void audit_receive_skb(struct sk_buff
*skb
)
908 struct nlmsghdr
*nlh
;
910 * len MUST be signed for NLMSG_NEXT to be able to dec it below 0
911 * if the nlmsg_len was not aligned
916 nlh
= nlmsg_hdr(skb
);
919 while (NLMSG_OK(nlh
, len
)) {
920 err
= audit_receive_msg(skb
, nlh
);
921 /* if err or if this message says it wants a response */
922 if (err
|| (nlh
->nlmsg_flags
& NLM_F_ACK
))
923 netlink_ack(skb
, nlh
, err
);
925 nlh
= NLMSG_NEXT(nlh
, len
);
929 /* Receive messages from netlink socket. */
930 static void audit_receive(struct sk_buff
*skb
)
932 mutex_lock(&audit_cmd_mutex
);
933 audit_receive_skb(skb
);
934 mutex_unlock(&audit_cmd_mutex
);
937 /* Initialize audit support at boot time. */
938 static int __init
audit_init(void)
941 struct netlink_kernel_cfg cfg
= {
942 .input
= audit_receive
,
945 if (audit_initialized
== AUDIT_DISABLED
)
948 printk(KERN_INFO
"audit: initializing netlink socket (%s)\n",
949 audit_default
? "enabled" : "disabled");
950 audit_sock
= netlink_kernel_create(&init_net
, NETLINK_AUDIT
,
953 audit_panic("cannot initialize netlink socket");
955 audit_sock
->sk_sndtimeo
= MAX_SCHEDULE_TIMEOUT
;
957 skb_queue_head_init(&audit_skb_queue
);
958 skb_queue_head_init(&audit_skb_hold_queue
);
959 audit_initialized
= AUDIT_INITIALIZED
;
960 audit_enabled
= audit_default
;
961 audit_ever_enabled
|= !!audit_default
;
963 audit_log(NULL
, GFP_KERNEL
, AUDIT_KERNEL
, "initialized");
965 for (i
= 0; i
< AUDIT_INODE_BUCKETS
; i
++)
966 INIT_LIST_HEAD(&audit_inode_hash
[i
]);
970 __initcall(audit_init
);
972 /* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
973 static int __init
audit_enable(char *str
)
975 audit_default
= !!simple_strtol(str
, NULL
, 0);
977 audit_initialized
= AUDIT_DISABLED
;
979 printk(KERN_INFO
"audit: %s", audit_default
? "enabled" : "disabled");
981 if (audit_initialized
== AUDIT_INITIALIZED
) {
982 audit_enabled
= audit_default
;
983 audit_ever_enabled
|= !!audit_default
;
984 } else if (audit_initialized
== AUDIT_UNINITIALIZED
) {
985 printk(" (after initialization)");
987 printk(" (until reboot)");
994 __setup("audit=", audit_enable
);
996 static void audit_buffer_free(struct audit_buffer
*ab
)
1006 spin_lock_irqsave(&audit_freelist_lock
, flags
);
1007 if (audit_freelist_count
> AUDIT_MAXFREE
)
1010 audit_freelist_count
++;
1011 list_add(&ab
->list
, &audit_freelist
);
1013 spin_unlock_irqrestore(&audit_freelist_lock
, flags
);
1016 static struct audit_buffer
* audit_buffer_alloc(struct audit_context
*ctx
,
1017 gfp_t gfp_mask
, int type
)
1019 unsigned long flags
;
1020 struct audit_buffer
*ab
= NULL
;
1021 struct nlmsghdr
*nlh
;
1023 spin_lock_irqsave(&audit_freelist_lock
, flags
);
1024 if (!list_empty(&audit_freelist
)) {
1025 ab
= list_entry(audit_freelist
.next
,
1026 struct audit_buffer
, list
);
1027 list_del(&ab
->list
);
1028 --audit_freelist_count
;
1030 spin_unlock_irqrestore(&audit_freelist_lock
, flags
);
1033 ab
= kmalloc(sizeof(*ab
), gfp_mask
);
1039 ab
->gfp_mask
= gfp_mask
;
1041 ab
->skb
= nlmsg_new(AUDIT_BUFSIZ
, gfp_mask
);
1045 nlh
= nlmsg_put(ab
->skb
, 0, 0, type
, 0, 0);
1055 audit_buffer_free(ab
);
1060 * audit_serial - compute a serial number for the audit record
1062 * Compute a serial number for the audit record. Audit records are
1063 * written to user-space as soon as they are generated, so a complete
1064 * audit record may be written in several pieces. The timestamp of the
1065 * record and this serial number are used by the user-space tools to
1066 * determine which pieces belong to the same audit record. The
1067 * (timestamp,serial) tuple is unique for each syscall and is live from
1068 * syscall entry to syscall exit.
1070 * NOTE: Another possibility is to store the formatted records off the
1071 * audit context (for those records that have a context), and emit them
1072 * all at syscall exit. However, this could delay the reporting of
1073 * significant errors until syscall exit (or never, if the system
1076 unsigned int audit_serial(void)
1078 static DEFINE_SPINLOCK(serial_lock
);
1079 static unsigned int serial
= 0;
1081 unsigned long flags
;
1084 spin_lock_irqsave(&serial_lock
, flags
);
1087 } while (unlikely(!ret
));
1088 spin_unlock_irqrestore(&serial_lock
, flags
);
1093 static inline void audit_get_stamp(struct audit_context
*ctx
,
1094 struct timespec
*t
, unsigned int *serial
)
1096 if (!ctx
|| !auditsc_get_stamp(ctx
, t
, serial
)) {
1098 *serial
= audit_serial();
1102 /* Obtain an audit buffer. This routine does locking to obtain the
1103 * audit buffer, but then no locking is required for calls to
1104 * audit_log_*format. If the tsk is a task that is currently in a
1105 * syscall, then the syscall is marked as auditable and an audit record
1106 * will be written at syscall exit. If there is no associated task, tsk
1107 * should be NULL. */
1110 * audit_log_start - obtain an audit buffer
1111 * @ctx: audit_context (may be NULL)
1112 * @gfp_mask: type of allocation
1113 * @type: audit message type
1115 * Returns audit_buffer pointer on success or NULL on error.
1117 * Obtain an audit buffer. This routine does locking to obtain the
1118 * audit buffer, but then no locking is required for calls to
1119 * audit_log_*format. If the task (ctx) is a task that is currently in a
1120 * syscall, then the syscall is marked as auditable and an audit record
1121 * will be written at syscall exit. If there is no associated task, then
1122 * task context (ctx) should be NULL.
1124 struct audit_buffer
*audit_log_start(struct audit_context
*ctx
, gfp_t gfp_mask
,
1127 struct audit_buffer
*ab
= NULL
;
1129 unsigned int uninitialized_var(serial
);
1131 unsigned long timeout_start
= jiffies
;
1133 if (audit_initialized
!= AUDIT_INITIALIZED
)
1136 if (unlikely(audit_filter_type(type
)))
1139 if (gfp_mask
& __GFP_WAIT
)
1142 reserve
= 5; /* Allow atomic callers to go up to five
1143 entries over the normal backlog limit */
1145 while (audit_backlog_limit
1146 && skb_queue_len(&audit_skb_queue
) > audit_backlog_limit
+ reserve
) {
1147 if (gfp_mask
& __GFP_WAIT
&& audit_backlog_wait_time
1148 && time_before(jiffies
, timeout_start
+ audit_backlog_wait_time
)) {
1150 /* Wait for auditd to drain the queue a little */
1151 DECLARE_WAITQUEUE(wait
, current
);
1152 set_current_state(TASK_INTERRUPTIBLE
);
1153 add_wait_queue(&audit_backlog_wait
, &wait
);
1155 if (audit_backlog_limit
&&
1156 skb_queue_len(&audit_skb_queue
) > audit_backlog_limit
)
1157 schedule_timeout(timeout_start
+ audit_backlog_wait_time
- jiffies
);
1159 __set_current_state(TASK_RUNNING
);
1160 remove_wait_queue(&audit_backlog_wait
, &wait
);
1163 if (audit_rate_check() && printk_ratelimit())
1165 "audit: audit_backlog=%d > "
1166 "audit_backlog_limit=%d\n",
1167 skb_queue_len(&audit_skb_queue
),
1168 audit_backlog_limit
);
1169 audit_log_lost("backlog limit exceeded");
1170 audit_backlog_wait_time
= audit_backlog_wait_overflow
;
1171 wake_up(&audit_backlog_wait
);
1175 ab
= audit_buffer_alloc(ctx
, gfp_mask
, type
);
1177 audit_log_lost("out of memory in audit_log_start");
1181 audit_get_stamp(ab
->ctx
, &t
, &serial
);
1183 audit_log_format(ab
, "audit(%lu.%03lu:%u): ",
1184 t
.tv_sec
, t
.tv_nsec
/1000000, serial
);
1189 * audit_expand - expand skb in the audit buffer
1191 * @extra: space to add at tail of the skb
1193 * Returns 0 (no space) on failed expansion, or available space if
1196 static inline int audit_expand(struct audit_buffer
*ab
, int extra
)
1198 struct sk_buff
*skb
= ab
->skb
;
1199 int oldtail
= skb_tailroom(skb
);
1200 int ret
= pskb_expand_head(skb
, 0, extra
, ab
->gfp_mask
);
1201 int newtail
= skb_tailroom(skb
);
1204 audit_log_lost("out of memory in audit_expand");
1208 skb
->truesize
+= newtail
- oldtail
;
1213 * Format an audit message into the audit buffer. If there isn't enough
1214 * room in the audit buffer, more room will be allocated and vsnprint
1215 * will be called a second time. Currently, we assume that a printk
1216 * can't format message larger than 1024 bytes, so we don't either.
1218 static void audit_log_vformat(struct audit_buffer
*ab
, const char *fmt
,
1222 struct sk_buff
*skb
;
1230 avail
= skb_tailroom(skb
);
1232 avail
= audit_expand(ab
, AUDIT_BUFSIZ
);
1236 va_copy(args2
, args
);
1237 len
= vsnprintf(skb_tail_pointer(skb
), avail
, fmt
, args
);
1239 /* The printk buffer is 1024 bytes long, so if we get
1240 * here and AUDIT_BUFSIZ is at least 1024, then we can
1241 * log everything that printk could have logged. */
1242 avail
= audit_expand(ab
,
1243 max_t(unsigned, AUDIT_BUFSIZ
, 1+len
-avail
));
1246 len
= vsnprintf(skb_tail_pointer(skb
), avail
, fmt
, args2
);
1257 * audit_log_format - format a message into the audit buffer.
1259 * @fmt: format string
1260 * @...: optional parameters matching @fmt string
1262 * All the work is done in audit_log_vformat.
1264 void audit_log_format(struct audit_buffer
*ab
, const char *fmt
, ...)
1270 va_start(args
, fmt
);
1271 audit_log_vformat(ab
, fmt
, args
);
1276 * audit_log_hex - convert a buffer to hex and append it to the audit skb
1277 * @ab: the audit_buffer
1278 * @buf: buffer to convert to hex
1279 * @len: length of @buf to be converted
1281 * No return value; failure to expand is silently ignored.
1283 * This function will take the passed buf and convert it into a string of
1284 * ascii hex digits. The new string is placed onto the skb.
1286 void audit_log_n_hex(struct audit_buffer
*ab
, const unsigned char *buf
,
1289 int i
, avail
, new_len
;
1291 struct sk_buff
*skb
;
1292 static const unsigned char *hex
= "0123456789ABCDEF";
1299 avail
= skb_tailroom(skb
);
1301 if (new_len
>= avail
) {
1302 /* Round the buffer request up to the next multiple */
1303 new_len
= AUDIT_BUFSIZ
*(((new_len
-avail
)/AUDIT_BUFSIZ
) + 1);
1304 avail
= audit_expand(ab
, new_len
);
1309 ptr
= skb_tail_pointer(skb
);
1310 for (i
=0; i
<len
; i
++) {
1311 *ptr
++ = hex
[(buf
[i
] & 0xF0)>>4]; /* Upper nibble */
1312 *ptr
++ = hex
[buf
[i
] & 0x0F]; /* Lower nibble */
1315 skb_put(skb
, len
<< 1); /* new string is twice the old string */
1319 * Format a string of no more than slen characters into the audit buffer,
1320 * enclosed in quote marks.
1322 void audit_log_n_string(struct audit_buffer
*ab
, const char *string
,
1327 struct sk_buff
*skb
;
1334 avail
= skb_tailroom(skb
);
1335 new_len
= slen
+ 3; /* enclosing quotes + null terminator */
1336 if (new_len
> avail
) {
1337 avail
= audit_expand(ab
, new_len
);
1341 ptr
= skb_tail_pointer(skb
);
1343 memcpy(ptr
, string
, slen
);
1347 skb_put(skb
, slen
+ 2); /* don't include null terminator */
1351 * audit_string_contains_control - does a string need to be logged in hex
1352 * @string: string to be checked
1353 * @len: max length of the string to check
1355 int audit_string_contains_control(const char *string
, size_t len
)
1357 const unsigned char *p
;
1358 for (p
= string
; p
< (const unsigned char *)string
+ len
; p
++) {
1359 if (*p
== '"' || *p
< 0x21 || *p
> 0x7e)
1366 * audit_log_n_untrustedstring - log a string that may contain random characters
1368 * @len: length of string (not including trailing null)
1369 * @string: string to be logged
1371 * This code will escape a string that is passed to it if the string
1372 * contains a control character, unprintable character, double quote mark,
1373 * or a space. Unescaped strings will start and end with a double quote mark.
1374 * Strings that are escaped are printed in hex (2 digits per char).
1376 * The caller specifies the number of characters in the string to log, which may
1377 * or may not be the entire string.
1379 void audit_log_n_untrustedstring(struct audit_buffer
*ab
, const char *string
,
1382 if (audit_string_contains_control(string
, len
))
1383 audit_log_n_hex(ab
, string
, len
);
1385 audit_log_n_string(ab
, string
, len
);
1389 * audit_log_untrustedstring - log a string that may contain random characters
1391 * @string: string to be logged
1393 * Same as audit_log_n_untrustedstring(), except that strlen is used to
1394 * determine string length.
1396 void audit_log_untrustedstring(struct audit_buffer
*ab
, const char *string
)
1398 audit_log_n_untrustedstring(ab
, string
, strlen(string
));
1401 /* This is a helper-function to print the escaped d_path */
1402 void audit_log_d_path(struct audit_buffer
*ab
, const char *prefix
,
1403 const struct path
*path
)
1408 audit_log_format(ab
, "%s", prefix
);
1410 /* We will allow 11 spaces for ' (deleted)' to be appended */
1411 pathname
= kmalloc(PATH_MAX
+11, ab
->gfp_mask
);
1413 audit_log_string(ab
, "<no_memory>");
1416 p
= d_path(path
, pathname
, PATH_MAX
+11);
1417 if (IS_ERR(p
)) { /* Should never happen since we send PATH_MAX */
1418 /* FIXME: can we save some information here? */
1419 audit_log_string(ab
, "<too_long>");
1421 audit_log_untrustedstring(ab
, p
);
1425 void audit_log_key(struct audit_buffer
*ab
, char *key
)
1427 audit_log_format(ab
, " key=");
1429 audit_log_untrustedstring(ab
, key
);
1431 audit_log_format(ab
, "(null)");
1435 * audit_log_link_denied - report a link restriction denial
1436 * @operation: specific link opreation
1437 * @link: the path that triggered the restriction
1439 void audit_log_link_denied(const char *operation
, struct path
*link
)
1441 struct audit_buffer
*ab
;
1443 ab
= audit_log_start(current
->audit_context
, GFP_KERNEL
,
1445 audit_log_format(ab
, "op=%s action=denied", operation
);
1446 audit_log_format(ab
, " pid=%d comm=", current
->pid
);
1447 audit_log_untrustedstring(ab
, current
->comm
);
1448 audit_log_d_path(ab
, " path=", link
);
1449 audit_log_format(ab
, " dev=");
1450 audit_log_untrustedstring(ab
, link
->dentry
->d_inode
->i_sb
->s_id
);
1451 audit_log_format(ab
, " ino=%lu", link
->dentry
->d_inode
->i_ino
);
1456 * audit_log_end - end one audit record
1457 * @ab: the audit_buffer
1459 * The netlink_* functions cannot be called inside an irq context, so
1460 * the audit buffer is placed on a queue and a tasklet is scheduled to
1461 * remove them from the queue outside the irq context. May be called in
1464 void audit_log_end(struct audit_buffer
*ab
)
1468 if (!audit_rate_check()) {
1469 audit_log_lost("rate limit exceeded");
1471 struct nlmsghdr
*nlh
= nlmsg_hdr(ab
->skb
);
1472 nlh
->nlmsg_len
= ab
->skb
->len
- NLMSG_SPACE(0);
1475 skb_queue_tail(&audit_skb_queue
, ab
->skb
);
1476 wake_up_interruptible(&kauditd_wait
);
1478 audit_printk_skb(ab
->skb
);
1482 audit_buffer_free(ab
);
1486 * audit_log - Log an audit record
1487 * @ctx: audit context
1488 * @gfp_mask: type of allocation
1489 * @type: audit message type
1490 * @fmt: format string to use
1491 * @...: variable parameters matching the format string
1493 * This is a convenience function that calls audit_log_start,
1494 * audit_log_vformat, and audit_log_end. It may be called
1497 void audit_log(struct audit_context
*ctx
, gfp_t gfp_mask
, int type
,
1498 const char *fmt
, ...)
1500 struct audit_buffer
*ab
;
1503 ab
= audit_log_start(ctx
, gfp_mask
, type
);
1505 va_start(args
, fmt
);
1506 audit_log_vformat(ab
, fmt
, args
);
1512 #ifdef CONFIG_SECURITY
1514 * audit_log_secctx - Converts and logs SELinux context
1516 * @secid: security number
1518 * This is a helper function that calls security_secid_to_secctx to convert
1519 * secid to secctx and then adds the (converted) SELinux context to the audit
1520 * log by calling audit_log_format, thus also preventing leak of internal secid
1521 * to userspace. If secid cannot be converted audit_panic is called.
1523 void audit_log_secctx(struct audit_buffer
*ab
, u32 secid
)
1528 if (security_secid_to_secctx(secid
, &secctx
, &len
)) {
1529 audit_panic("Cannot convert secid to context");
1531 audit_log_format(ab
, " obj=%s", secctx
);
1532 security_release_secctx(secctx
, len
);
1535 EXPORT_SYMBOL(audit_log_secctx
);
1538 EXPORT_SYMBOL(audit_log_start
);
1539 EXPORT_SYMBOL(audit_log_end
);
1540 EXPORT_SYMBOL(audit_log_format
);
1541 EXPORT_SYMBOL(audit_log
);