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>
67 /* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
68 * (Initialization happens after skb_init is called.) */
69 #define AUDIT_DISABLED -1
70 #define AUDIT_UNINITIALIZED 0
71 #define AUDIT_INITIALIZED 1
72 static int audit_initialized
;
76 #define AUDIT_LOCKED 2
78 int audit_ever_enabled
;
80 EXPORT_SYMBOL_GPL(audit_enabled
);
82 /* Default state when kernel boots without any parameters. */
83 static int audit_default
;
85 /* If auditing cannot proceed, audit_failure selects what happens. */
86 static int audit_failure
= AUDIT_FAIL_PRINTK
;
89 * If audit records are to be written to the netlink socket, audit_pid
90 * contains the pid of the auditd process and audit_nlk_portid contains
91 * the portid to use to send netlink messages to that process.
94 static int audit_nlk_portid
;
96 /* If audit_rate_limit is non-zero, limit the rate of sending audit records
97 * to that number per second. This prevents DoS attacks, but results in
98 * audit records being dropped. */
99 static int audit_rate_limit
;
101 /* Number of outstanding audit_buffers allowed. */
102 static int audit_backlog_limit
= 64;
103 static int audit_backlog_wait_time
= 60 * HZ
;
104 static int audit_backlog_wait_overflow
= 0;
106 /* The identity of the user shutting down the audit system. */
107 uid_t audit_sig_uid
= -1;
108 pid_t audit_sig_pid
= -1;
109 u32 audit_sig_sid
= 0;
111 /* Records can be lost in several ways:
112 0) [suppressed in audit_alloc]
113 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
114 2) out of memory in audit_log_move [alloc_skb]
115 3) suppressed due to audit_rate_limit
116 4) suppressed due to audit_backlog_limit
118 static atomic_t audit_lost
= ATOMIC_INIT(0);
120 /* The netlink socket. */
121 static struct sock
*audit_sock
;
123 /* Hash for inode-based rules */
124 struct list_head audit_inode_hash
[AUDIT_INODE_BUCKETS
];
126 /* The audit_freelist is a list of pre-allocated audit buffers (if more
127 * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
128 * being placed on the freelist). */
129 static DEFINE_SPINLOCK(audit_freelist_lock
);
130 static int audit_freelist_count
;
131 static LIST_HEAD(audit_freelist
);
133 static struct sk_buff_head audit_skb_queue
;
134 /* queue of skbs to send to auditd when/if it comes back */
135 static struct sk_buff_head audit_skb_hold_queue
;
136 static struct task_struct
*kauditd_task
;
137 static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait
);
138 static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait
);
140 /* Serialize requests from userspace. */
141 DEFINE_MUTEX(audit_cmd_mutex
);
143 /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
144 * audit records. Since printk uses a 1024 byte buffer, this buffer
145 * should be at least that large. */
146 #define AUDIT_BUFSIZ 1024
148 /* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the
149 * audit_freelist. Doing so eliminates many kmalloc/kfree calls. */
150 #define AUDIT_MAXFREE (2*NR_CPUS)
152 /* The audit_buffer is used when formatting an audit record. The caller
153 * locks briefly to get the record off the freelist or to allocate the
154 * buffer, and locks briefly to send the buffer to the netlink layer or
155 * to place it on a transmit queue. Multiple audit_buffers can be in
156 * use simultaneously. */
157 struct audit_buffer
{
158 struct list_head list
;
159 struct sk_buff
*skb
; /* formatted skb ready to send */
160 struct audit_context
*ctx
; /* NULL or associated context */
169 static void audit_set_pid(struct audit_buffer
*ab
, pid_t pid
)
172 struct nlmsghdr
*nlh
= nlmsg_hdr(ab
->skb
);
173 nlh
->nlmsg_pid
= pid
;
177 void audit_panic(const char *message
)
179 switch (audit_failure
)
181 case AUDIT_FAIL_SILENT
:
183 case AUDIT_FAIL_PRINTK
:
184 if (printk_ratelimit())
185 printk(KERN_ERR
"audit: %s\n", message
);
187 case AUDIT_FAIL_PANIC
:
188 /* test audit_pid since printk is always losey, why bother? */
190 panic("audit: %s\n", message
);
195 static inline int audit_rate_check(void)
197 static unsigned long last_check
= 0;
198 static int messages
= 0;
199 static DEFINE_SPINLOCK(lock
);
202 unsigned long elapsed
;
205 if (!audit_rate_limit
) return 1;
207 spin_lock_irqsave(&lock
, flags
);
208 if (++messages
< audit_rate_limit
) {
212 elapsed
= now
- last_check
;
219 spin_unlock_irqrestore(&lock
, flags
);
225 * audit_log_lost - conditionally log lost audit message event
226 * @message: the message stating reason for lost audit message
228 * Emit at least 1 message per second, even if audit_rate_check is
230 * Always increment the lost messages counter.
232 void audit_log_lost(const char *message
)
234 static unsigned long last_msg
= 0;
235 static DEFINE_SPINLOCK(lock
);
240 atomic_inc(&audit_lost
);
242 print
= (audit_failure
== AUDIT_FAIL_PANIC
|| !audit_rate_limit
);
245 spin_lock_irqsave(&lock
, flags
);
247 if (now
- last_msg
> HZ
) {
251 spin_unlock_irqrestore(&lock
, flags
);
255 if (printk_ratelimit())
257 "audit: audit_lost=%d audit_rate_limit=%d "
258 "audit_backlog_limit=%d\n",
259 atomic_read(&audit_lost
),
261 audit_backlog_limit
);
262 audit_panic(message
);
266 static int audit_log_config_change(char *function_name
, int new, int old
,
267 uid_t loginuid
, u32 sessionid
, u32 sid
,
270 struct audit_buffer
*ab
;
273 ab
= audit_log_start(NULL
, GFP_KERNEL
, AUDIT_CONFIG_CHANGE
);
274 audit_log_format(ab
, "%s=%d old=%d auid=%u ses=%u", function_name
, new,
275 old
, loginuid
, sessionid
);
280 rc
= security_secid_to_secctx(sid
, &ctx
, &len
);
282 audit_log_format(ab
, " sid=%u", sid
);
283 allow_changes
= 0; /* Something weird, deny request */
285 audit_log_format(ab
, " subj=%s", ctx
);
286 security_release_secctx(ctx
, len
);
289 audit_log_format(ab
, " res=%d", allow_changes
);
294 static int audit_do_config_change(char *function_name
, int *to_change
,
295 int new, uid_t loginuid
, u32 sessionid
,
298 int allow_changes
, rc
= 0, old
= *to_change
;
300 /* check if we are locked */
301 if (audit_enabled
== AUDIT_LOCKED
)
306 if (audit_enabled
!= AUDIT_OFF
) {
307 rc
= audit_log_config_change(function_name
, new, old
, loginuid
,
308 sessionid
, sid
, allow_changes
);
313 /* If we are allowed, make the change */
314 if (allow_changes
== 1)
316 /* Not allowed, update reason */
322 static int audit_set_rate_limit(int limit
, uid_t loginuid
, u32 sessionid
,
325 return audit_do_config_change("audit_rate_limit", &audit_rate_limit
,
326 limit
, loginuid
, sessionid
, sid
);
329 static int audit_set_backlog_limit(int limit
, uid_t loginuid
, u32 sessionid
,
332 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit
,
333 limit
, loginuid
, sessionid
, sid
);
336 static int audit_set_enabled(int state
, uid_t loginuid
, u32 sessionid
, u32 sid
)
339 if (state
< AUDIT_OFF
|| state
> AUDIT_LOCKED
)
342 rc
= audit_do_config_change("audit_enabled", &audit_enabled
, state
,
343 loginuid
, sessionid
, sid
);
346 audit_ever_enabled
|= !!state
;
351 static int audit_set_failure(int state
, uid_t loginuid
, u32 sessionid
, u32 sid
)
353 if (state
!= AUDIT_FAIL_SILENT
354 && state
!= AUDIT_FAIL_PRINTK
355 && state
!= AUDIT_FAIL_PANIC
)
358 return audit_do_config_change("audit_failure", &audit_failure
, state
,
359 loginuid
, sessionid
, sid
);
363 * Queue skbs to be sent to auditd when/if it comes back. These skbs should
364 * already have been sent via prink/syslog and so if these messages are dropped
365 * it is not a huge concern since we already passed the audit_log_lost()
366 * notification and stuff. This is just nice to get audit messages during
367 * boot before auditd is running or messages generated while auditd is stopped.
368 * This only holds messages is audit_default is set, aka booting with audit=1
369 * or building your kernel that way.
371 static void audit_hold_skb(struct sk_buff
*skb
)
374 skb_queue_len(&audit_skb_hold_queue
) < audit_backlog_limit
)
375 skb_queue_tail(&audit_skb_hold_queue
, skb
);
381 * For one reason or another this nlh isn't getting delivered to the userspace
382 * audit daemon, just send it to printk.
384 static void audit_printk_skb(struct sk_buff
*skb
)
386 struct nlmsghdr
*nlh
= nlmsg_hdr(skb
);
387 char *data
= nlmsg_data(nlh
);
389 if (nlh
->nlmsg_type
!= AUDIT_EOE
) {
390 if (printk_ratelimit())
391 printk(KERN_NOTICE
"type=%d %s\n", nlh
->nlmsg_type
, data
);
393 audit_log_lost("printk limit exceeded\n");
399 static void kauditd_send_skb(struct sk_buff
*skb
)
402 /* take a reference in case we can't send it and we want to hold it */
404 err
= netlink_unicast(audit_sock
, skb
, audit_nlk_portid
, 0);
406 BUG_ON(err
!= -ECONNREFUSED
); /* Shouldn't happen */
407 printk(KERN_ERR
"audit: *NO* daemon at audit_pid=%d\n", audit_pid
);
408 audit_log_lost("auditd disappeared\n");
410 /* we might get lucky and get this in the next auditd */
413 /* drop the extra reference if sent ok */
417 static int kauditd_thread(void *dummy
)
422 while (!kthread_should_stop()) {
424 * if auditd just started drain the queue of messages already
425 * sent to syslog/printk. remember loss here is ok. we already
426 * called audit_log_lost() if it didn't go out normally. so the
427 * race between the skb_dequeue and the next check for audit_pid
430 * if you ever find kauditd to be too slow we can get a perf win
431 * by doing our own locking and keeping better track if there
432 * are messages in this queue. I don't see the need now, but
433 * in 5 years when I want to play with this again I'll see this
434 * note and still have no friggin idea what i'm thinking today.
436 if (audit_default
&& audit_pid
) {
437 skb
= skb_dequeue(&audit_skb_hold_queue
);
439 while (skb
&& audit_pid
) {
440 kauditd_send_skb(skb
);
441 skb
= skb_dequeue(&audit_skb_hold_queue
);
446 skb
= skb_dequeue(&audit_skb_queue
);
447 wake_up(&audit_backlog_wait
);
450 kauditd_send_skb(skb
);
452 audit_printk_skb(skb
);
454 DECLARE_WAITQUEUE(wait
, current
);
455 set_current_state(TASK_INTERRUPTIBLE
);
456 add_wait_queue(&kauditd_wait
, &wait
);
458 if (!skb_queue_len(&audit_skb_queue
)) {
463 __set_current_state(TASK_RUNNING
);
464 remove_wait_queue(&kauditd_wait
, &wait
);
470 static int audit_prepare_user_tty(pid_t pid
, uid_t loginuid
, u32 sessionid
)
472 struct task_struct
*tsk
;
476 tsk
= find_task_by_vpid(pid
);
481 get_task_struct(tsk
);
483 err
= tty_audit_push_task(tsk
, loginuid
, sessionid
);
484 put_task_struct(tsk
);
488 int audit_send_list(void *_dest
)
490 struct audit_netlink_list
*dest
= _dest
;
494 /* wait for parent to finish and send an ACK */
495 mutex_lock(&audit_cmd_mutex
);
496 mutex_unlock(&audit_cmd_mutex
);
498 while ((skb
= __skb_dequeue(&dest
->q
)) != NULL
)
499 netlink_unicast(audit_sock
, skb
, pid
, 0);
506 struct sk_buff
*audit_make_reply(int pid
, int seq
, int type
, int done
,
507 int multi
, const void *payload
, int size
)
510 struct nlmsghdr
*nlh
;
512 int flags
= multi
? NLM_F_MULTI
: 0;
513 int t
= done
? NLMSG_DONE
: type
;
515 skb
= nlmsg_new(size
, GFP_KERNEL
);
519 nlh
= nlmsg_put(skb
, pid
, seq
, t
, size
, flags
);
522 data
= nlmsg_data(nlh
);
523 memcpy(data
, payload
, size
);
531 static int audit_send_reply_thread(void *arg
)
533 struct audit_reply
*reply
= (struct audit_reply
*)arg
;
535 mutex_lock(&audit_cmd_mutex
);
536 mutex_unlock(&audit_cmd_mutex
);
538 /* Ignore failure. It'll only happen if the sender goes away,
539 because our timeout is set to infinite. */
540 netlink_unicast(audit_sock
, reply
->skb
, reply
->pid
, 0);
545 * audit_send_reply - send an audit reply message via netlink
546 * @pid: process id to send reply to
547 * @seq: sequence number
548 * @type: audit message type
549 * @done: done (last) flag
550 * @multi: multi-part message flag
551 * @payload: payload data
552 * @size: payload size
554 * Allocates an skb, builds the netlink message, and sends it to the pid.
555 * No failure notifications.
557 static void audit_send_reply(int pid
, int seq
, int type
, int done
, int multi
,
558 const void *payload
, int size
)
561 struct task_struct
*tsk
;
562 struct audit_reply
*reply
= kmalloc(sizeof(struct audit_reply
),
568 skb
= audit_make_reply(pid
, seq
, type
, done
, multi
, payload
, size
);
575 tsk
= kthread_run(audit_send_reply_thread
, reply
, "audit_send_reply");
584 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
587 static int audit_netlink_ok(struct sk_buff
*skb
, u16 msg_type
)
594 case AUDIT_LIST_RULES
:
600 case AUDIT_SIGNAL_INFO
:
604 case AUDIT_MAKE_EQUIV
:
605 if (!capable(CAP_AUDIT_CONTROL
))
609 case AUDIT_FIRST_USER_MSG
... AUDIT_LAST_USER_MSG
:
610 case AUDIT_FIRST_USER_MSG2
... AUDIT_LAST_USER_MSG2
:
611 if (!capable(CAP_AUDIT_WRITE
))
614 default: /* bad msg */
621 static int audit_log_common_recv_msg(struct audit_buffer
**ab
, u16 msg_type
,
622 u32 pid
, u32 uid
, uid_t auid
, u32 ses
,
629 if (!audit_enabled
) {
634 *ab
= audit_log_start(NULL
, GFP_KERNEL
, msg_type
);
635 audit_log_format(*ab
, "pid=%d uid=%u auid=%u ses=%u",
636 pid
, uid
, auid
, ses
);
638 rc
= security_secid_to_secctx(sid
, &ctx
, &len
);
640 audit_log_format(*ab
, " ssid=%u", sid
);
642 audit_log_format(*ab
, " subj=%s", ctx
);
643 security_release_secctx(ctx
, len
);
650 static int audit_receive_msg(struct sk_buff
*skb
, struct nlmsghdr
*nlh
)
652 u32 uid
, pid
, seq
, sid
;
654 struct audit_status
*status_get
, status_set
;
656 struct audit_buffer
*ab
;
657 u16 msg_type
= nlh
->nlmsg_type
;
658 uid_t loginuid
; /* loginuid of sender */
660 struct audit_sig_info
*sig_data
;
664 err
= audit_netlink_ok(skb
, msg_type
);
668 /* As soon as there's any sign of userspace auditd,
669 * start kauditd to talk to it */
671 kauditd_task
= kthread_run(kauditd_thread
, NULL
, "kauditd");
672 if (IS_ERR(kauditd_task
)) {
673 err
= PTR_ERR(kauditd_task
);
678 pid
= NETLINK_CREDS(skb
)->pid
;
679 uid
= NETLINK_CREDS(skb
)->uid
;
680 loginuid
= audit_get_loginuid(current
);
681 sessionid
= audit_get_sessionid(current
);
682 security_task_getsecid(current
, &sid
);
683 seq
= nlh
->nlmsg_seq
;
684 data
= nlmsg_data(nlh
);
688 status_set
.enabled
= audit_enabled
;
689 status_set
.failure
= audit_failure
;
690 status_set
.pid
= audit_pid
;
691 status_set
.rate_limit
= audit_rate_limit
;
692 status_set
.backlog_limit
= audit_backlog_limit
;
693 status_set
.lost
= atomic_read(&audit_lost
);
694 status_set
.backlog
= skb_queue_len(&audit_skb_queue
);
695 audit_send_reply(NETLINK_CB(skb
).portid
, seq
, AUDIT_GET
, 0, 0,
696 &status_set
, sizeof(status_set
));
699 if (nlh
->nlmsg_len
< sizeof(struct audit_status
))
701 status_get
= (struct audit_status
*)data
;
702 if (status_get
->mask
& AUDIT_STATUS_ENABLED
) {
703 err
= audit_set_enabled(status_get
->enabled
,
704 loginuid
, sessionid
, sid
);
708 if (status_get
->mask
& AUDIT_STATUS_FAILURE
) {
709 err
= audit_set_failure(status_get
->failure
,
710 loginuid
, sessionid
, sid
);
714 if (status_get
->mask
& AUDIT_STATUS_PID
) {
715 int new_pid
= status_get
->pid
;
717 if (audit_enabled
!= AUDIT_OFF
)
718 audit_log_config_change("audit_pid", new_pid
,
723 audit_nlk_portid
= NETLINK_CB(skb
).portid
;
725 if (status_get
->mask
& AUDIT_STATUS_RATE_LIMIT
) {
726 err
= audit_set_rate_limit(status_get
->rate_limit
,
727 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
));
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
);
762 ((unsigned char *)data
)[size
- 1] == '\0')
764 audit_log_n_untrustedstring(ab
, data
, size
);
766 audit_set_pid(ab
, pid
);
772 if (nlmsg_len(nlh
) < sizeof(struct audit_rule
))
774 if (audit_enabled
== AUDIT_LOCKED
) {
775 audit_log_common_recv_msg(&ab
, AUDIT_CONFIG_CHANGE
, pid
,
776 uid
, loginuid
, sessionid
, sid
);
778 audit_log_format(ab
, " audit_enabled=%d res=0",
785 err
= audit_receive_filter(msg_type
, NETLINK_CB(skb
).portid
,
786 uid
, seq
, data
, nlmsg_len(nlh
),
787 loginuid
, sessionid
, sid
);
791 if (nlmsg_len(nlh
) < sizeof(struct audit_rule_data
))
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",
803 case AUDIT_LIST_RULES
:
804 err
= audit_receive_filter(msg_type
, NETLINK_CB(skb
).portid
,
805 uid
, seq
, data
, nlmsg_len(nlh
),
806 loginuid
, sessionid
, sid
);
811 audit_log_common_recv_msg(&ab
, AUDIT_CONFIG_CHANGE
, pid
,
812 uid
, loginuid
, sessionid
, sid
);
814 audit_log_format(ab
, " op=trim res=1");
817 case AUDIT_MAKE_EQUIV
: {
820 size_t msglen
= nlmsg_len(nlh
);
824 if (msglen
< 2 * sizeof(u32
))
826 memcpy(sizes
, bufp
, 2 * sizeof(u32
));
827 bufp
+= 2 * sizeof(u32
);
828 msglen
-= 2 * sizeof(u32
);
829 old
= audit_unpack_string(&bufp
, &msglen
, sizes
[0]);
834 new = audit_unpack_string(&bufp
, &msglen
, sizes
[1]);
840 /* OK, here comes... */
841 err
= audit_tag_tree(old
, new);
843 audit_log_common_recv_msg(&ab
, AUDIT_CONFIG_CHANGE
, pid
,
844 uid
, loginuid
, sessionid
, sid
);
846 audit_log_format(ab
, " op=make_equiv old=");
847 audit_log_untrustedstring(ab
, old
);
848 audit_log_format(ab
, " new=");
849 audit_log_untrustedstring(ab
, new);
850 audit_log_format(ab
, " res=%d", !err
);
856 case AUDIT_SIGNAL_INFO
:
859 err
= security_secid_to_secctx(audit_sig_sid
, &ctx
, &len
);
863 sig_data
= kmalloc(sizeof(*sig_data
) + len
, GFP_KERNEL
);
866 security_release_secctx(ctx
, len
);
869 sig_data
->uid
= audit_sig_uid
;
870 sig_data
->pid
= audit_sig_pid
;
872 memcpy(sig_data
->ctx
, ctx
, len
);
873 security_release_secctx(ctx
, len
);
875 audit_send_reply(NETLINK_CB(skb
).portid
, seq
, AUDIT_SIGNAL_INFO
,
876 0, 0, sig_data
, sizeof(*sig_data
) + len
);
879 case AUDIT_TTY_GET
: {
880 struct audit_tty_status s
;
881 struct task_struct
*tsk
;
885 tsk
= find_task_by_vpid(pid
);
886 if (tsk
&& lock_task_sighand(tsk
, &flags
)) {
887 s
.enabled
= tsk
->signal
->audit_tty
!= 0;
888 unlock_task_sighand(tsk
, &flags
);
894 audit_send_reply(NETLINK_CB(skb
).portid
, seq
,
895 AUDIT_TTY_GET
, 0, 0, &s
, sizeof(s
));
898 case AUDIT_TTY_SET
: {
899 struct audit_tty_status
*s
;
900 struct task_struct
*tsk
;
903 if (nlh
->nlmsg_len
< sizeof(struct audit_tty_status
))
906 if (s
->enabled
!= 0 && s
->enabled
!= 1)
909 tsk
= find_task_by_vpid(pid
);
910 if (tsk
&& lock_task_sighand(tsk
, &flags
)) {
911 tsk
->signal
->audit_tty
= s
->enabled
!= 0;
912 unlock_task_sighand(tsk
, &flags
);
923 return err
< 0 ? err
: 0;
927 * Get message from skb. Each message is processed by audit_receive_msg.
928 * Malformed skbs with wrong length are discarded silently.
930 static void audit_receive_skb(struct sk_buff
*skb
)
932 struct nlmsghdr
*nlh
;
934 * len MUST be signed for NLMSG_NEXT to be able to dec it below 0
935 * if the nlmsg_len was not aligned
940 nlh
= nlmsg_hdr(skb
);
943 while (NLMSG_OK(nlh
, len
)) {
944 err
= audit_receive_msg(skb
, nlh
);
945 /* if err or if this message says it wants a response */
946 if (err
|| (nlh
->nlmsg_flags
& NLM_F_ACK
))
947 netlink_ack(skb
, nlh
, err
);
949 nlh
= NLMSG_NEXT(nlh
, len
);
953 /* Receive messages from netlink socket. */
954 static void audit_receive(struct sk_buff
*skb
)
956 mutex_lock(&audit_cmd_mutex
);
957 audit_receive_skb(skb
);
958 mutex_unlock(&audit_cmd_mutex
);
961 /* Initialize audit support at boot time. */
962 static int __init
audit_init(void)
965 struct netlink_kernel_cfg cfg
= {
966 .input
= audit_receive
,
969 if (audit_initialized
== AUDIT_DISABLED
)
972 printk(KERN_INFO
"audit: initializing netlink socket (%s)\n",
973 audit_default
? "enabled" : "disabled");
974 audit_sock
= netlink_kernel_create(&init_net
, NETLINK_AUDIT
, &cfg
);
976 audit_panic("cannot initialize netlink socket");
978 audit_sock
->sk_sndtimeo
= MAX_SCHEDULE_TIMEOUT
;
980 skb_queue_head_init(&audit_skb_queue
);
981 skb_queue_head_init(&audit_skb_hold_queue
);
982 audit_initialized
= AUDIT_INITIALIZED
;
983 audit_enabled
= audit_default
;
984 audit_ever_enabled
|= !!audit_default
;
986 audit_log(NULL
, GFP_KERNEL
, AUDIT_KERNEL
, "initialized");
988 for (i
= 0; i
< AUDIT_INODE_BUCKETS
; i
++)
989 INIT_LIST_HEAD(&audit_inode_hash
[i
]);
993 __initcall(audit_init
);
995 /* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
996 static int __init
audit_enable(char *str
)
998 audit_default
= !!simple_strtol(str
, NULL
, 0);
1000 audit_initialized
= AUDIT_DISABLED
;
1002 printk(KERN_INFO
"audit: %s", audit_default
? "enabled" : "disabled");
1004 if (audit_initialized
== AUDIT_INITIALIZED
) {
1005 audit_enabled
= audit_default
;
1006 audit_ever_enabled
|= !!audit_default
;
1007 } else if (audit_initialized
== AUDIT_UNINITIALIZED
) {
1008 printk(" (after initialization)");
1010 printk(" (until reboot)");
1017 __setup("audit=", audit_enable
);
1019 static void audit_buffer_free(struct audit_buffer
*ab
)
1021 unsigned long flags
;
1029 spin_lock_irqsave(&audit_freelist_lock
, flags
);
1030 if (audit_freelist_count
> AUDIT_MAXFREE
)
1033 audit_freelist_count
++;
1034 list_add(&ab
->list
, &audit_freelist
);
1036 spin_unlock_irqrestore(&audit_freelist_lock
, flags
);
1039 static struct audit_buffer
* audit_buffer_alloc(struct audit_context
*ctx
,
1040 gfp_t gfp_mask
, int type
)
1042 unsigned long flags
;
1043 struct audit_buffer
*ab
= NULL
;
1044 struct nlmsghdr
*nlh
;
1046 spin_lock_irqsave(&audit_freelist_lock
, flags
);
1047 if (!list_empty(&audit_freelist
)) {
1048 ab
= list_entry(audit_freelist
.next
,
1049 struct audit_buffer
, list
);
1050 list_del(&ab
->list
);
1051 --audit_freelist_count
;
1053 spin_unlock_irqrestore(&audit_freelist_lock
, flags
);
1056 ab
= kmalloc(sizeof(*ab
), gfp_mask
);
1062 ab
->gfp_mask
= gfp_mask
;
1064 ab
->skb
= nlmsg_new(AUDIT_BUFSIZ
, gfp_mask
);
1068 nlh
= nlmsg_put(ab
->skb
, 0, 0, type
, 0, 0);
1078 audit_buffer_free(ab
);
1083 * audit_serial - compute a serial number for the audit record
1085 * Compute a serial number for the audit record. Audit records are
1086 * written to user-space as soon as they are generated, so a complete
1087 * audit record may be written in several pieces. The timestamp of the
1088 * record and this serial number are used by the user-space tools to
1089 * determine which pieces belong to the same audit record. The
1090 * (timestamp,serial) tuple is unique for each syscall and is live from
1091 * syscall entry to syscall exit.
1093 * NOTE: Another possibility is to store the formatted records off the
1094 * audit context (for those records that have a context), and emit them
1095 * all at syscall exit. However, this could delay the reporting of
1096 * significant errors until syscall exit (or never, if the system
1099 unsigned int audit_serial(void)
1101 static DEFINE_SPINLOCK(serial_lock
);
1102 static unsigned int serial
= 0;
1104 unsigned long flags
;
1107 spin_lock_irqsave(&serial_lock
, flags
);
1110 } while (unlikely(!ret
));
1111 spin_unlock_irqrestore(&serial_lock
, flags
);
1116 static inline void audit_get_stamp(struct audit_context
*ctx
,
1117 struct timespec
*t
, unsigned int *serial
)
1119 if (!ctx
|| !auditsc_get_stamp(ctx
, t
, serial
)) {
1121 *serial
= audit_serial();
1125 /* Obtain an audit buffer. This routine does locking to obtain the
1126 * audit buffer, but then no locking is required for calls to
1127 * audit_log_*format. If the tsk is a task that is currently in a
1128 * syscall, then the syscall is marked as auditable and an audit record
1129 * will be written at syscall exit. If there is no associated task, tsk
1130 * should be NULL. */
1133 * audit_log_start - obtain an audit buffer
1134 * @ctx: audit_context (may be NULL)
1135 * @gfp_mask: type of allocation
1136 * @type: audit message type
1138 * Returns audit_buffer pointer on success or NULL on error.
1140 * Obtain an audit buffer. This routine does locking to obtain the
1141 * audit buffer, but then no locking is required for calls to
1142 * audit_log_*format. If the task (ctx) is a task that is currently in a
1143 * syscall, then the syscall is marked as auditable and an audit record
1144 * will be written at syscall exit. If there is no associated task, then
1145 * task context (ctx) should be NULL.
1147 struct audit_buffer
*audit_log_start(struct audit_context
*ctx
, gfp_t gfp_mask
,
1150 struct audit_buffer
*ab
= NULL
;
1152 unsigned int uninitialized_var(serial
);
1154 unsigned long timeout_start
= jiffies
;
1156 if (audit_initialized
!= AUDIT_INITIALIZED
)
1159 if (unlikely(audit_filter_type(type
)))
1162 if (gfp_mask
& __GFP_WAIT
)
1165 reserve
= 5; /* Allow atomic callers to go up to five
1166 entries over the normal backlog limit */
1168 while (audit_backlog_limit
1169 && skb_queue_len(&audit_skb_queue
) > audit_backlog_limit
+ reserve
) {
1170 if (gfp_mask
& __GFP_WAIT
&& audit_backlog_wait_time
1171 && time_before(jiffies
, timeout_start
+ audit_backlog_wait_time
)) {
1173 /* Wait for auditd to drain the queue a little */
1174 DECLARE_WAITQUEUE(wait
, current
);
1175 set_current_state(TASK_INTERRUPTIBLE
);
1176 add_wait_queue(&audit_backlog_wait
, &wait
);
1178 if (audit_backlog_limit
&&
1179 skb_queue_len(&audit_skb_queue
) > audit_backlog_limit
)
1180 schedule_timeout(timeout_start
+ audit_backlog_wait_time
- jiffies
);
1182 __set_current_state(TASK_RUNNING
);
1183 remove_wait_queue(&audit_backlog_wait
, &wait
);
1186 if (audit_rate_check() && printk_ratelimit())
1188 "audit: audit_backlog=%d > "
1189 "audit_backlog_limit=%d\n",
1190 skb_queue_len(&audit_skb_queue
),
1191 audit_backlog_limit
);
1192 audit_log_lost("backlog limit exceeded");
1193 audit_backlog_wait_time
= audit_backlog_wait_overflow
;
1194 wake_up(&audit_backlog_wait
);
1198 ab
= audit_buffer_alloc(ctx
, gfp_mask
, type
);
1200 audit_log_lost("out of memory in audit_log_start");
1204 audit_get_stamp(ab
->ctx
, &t
, &serial
);
1206 audit_log_format(ab
, "audit(%lu.%03lu:%u): ",
1207 t
.tv_sec
, t
.tv_nsec
/1000000, serial
);
1212 * audit_expand - expand skb in the audit buffer
1214 * @extra: space to add at tail of the skb
1216 * Returns 0 (no space) on failed expansion, or available space if
1219 static inline int audit_expand(struct audit_buffer
*ab
, int extra
)
1221 struct sk_buff
*skb
= ab
->skb
;
1222 int oldtail
= skb_tailroom(skb
);
1223 int ret
= pskb_expand_head(skb
, 0, extra
, ab
->gfp_mask
);
1224 int newtail
= skb_tailroom(skb
);
1227 audit_log_lost("out of memory in audit_expand");
1231 skb
->truesize
+= newtail
- oldtail
;
1236 * Format an audit message into the audit buffer. If there isn't enough
1237 * room in the audit buffer, more room will be allocated and vsnprint
1238 * will be called a second time. Currently, we assume that a printk
1239 * can't format message larger than 1024 bytes, so we don't either.
1241 static void audit_log_vformat(struct audit_buffer
*ab
, const char *fmt
,
1245 struct sk_buff
*skb
;
1253 avail
= skb_tailroom(skb
);
1255 avail
= audit_expand(ab
, AUDIT_BUFSIZ
);
1259 va_copy(args2
, args
);
1260 len
= vsnprintf(skb_tail_pointer(skb
), avail
, fmt
, args
);
1262 /* The printk buffer is 1024 bytes long, so if we get
1263 * here and AUDIT_BUFSIZ is at least 1024, then we can
1264 * log everything that printk could have logged. */
1265 avail
= audit_expand(ab
,
1266 max_t(unsigned, AUDIT_BUFSIZ
, 1+len
-avail
));
1269 len
= vsnprintf(skb_tail_pointer(skb
), avail
, fmt
, args2
);
1280 * audit_log_format - format a message into the audit buffer.
1282 * @fmt: format string
1283 * @...: optional parameters matching @fmt string
1285 * All the work is done in audit_log_vformat.
1287 void audit_log_format(struct audit_buffer
*ab
, const char *fmt
, ...)
1293 va_start(args
, fmt
);
1294 audit_log_vformat(ab
, fmt
, args
);
1299 * audit_log_hex - convert a buffer to hex and append it to the audit skb
1300 * @ab: the audit_buffer
1301 * @buf: buffer to convert to hex
1302 * @len: length of @buf to be converted
1304 * No return value; failure to expand is silently ignored.
1306 * This function will take the passed buf and convert it into a string of
1307 * ascii hex digits. The new string is placed onto the skb.
1309 void audit_log_n_hex(struct audit_buffer
*ab
, const unsigned char *buf
,
1312 int i
, avail
, new_len
;
1314 struct sk_buff
*skb
;
1315 static const unsigned char *hex
= "0123456789ABCDEF";
1322 avail
= skb_tailroom(skb
);
1324 if (new_len
>= avail
) {
1325 /* Round the buffer request up to the next multiple */
1326 new_len
= AUDIT_BUFSIZ
*(((new_len
-avail
)/AUDIT_BUFSIZ
) + 1);
1327 avail
= audit_expand(ab
, new_len
);
1332 ptr
= skb_tail_pointer(skb
);
1333 for (i
=0; i
<len
; i
++) {
1334 *ptr
++ = hex
[(buf
[i
] & 0xF0)>>4]; /* Upper nibble */
1335 *ptr
++ = hex
[buf
[i
] & 0x0F]; /* Lower nibble */
1338 skb_put(skb
, len
<< 1); /* new string is twice the old string */
1342 * Format a string of no more than slen characters into the audit buffer,
1343 * enclosed in quote marks.
1345 void audit_log_n_string(struct audit_buffer
*ab
, const char *string
,
1350 struct sk_buff
*skb
;
1357 avail
= skb_tailroom(skb
);
1358 new_len
= slen
+ 3; /* enclosing quotes + null terminator */
1359 if (new_len
> avail
) {
1360 avail
= audit_expand(ab
, new_len
);
1364 ptr
= skb_tail_pointer(skb
);
1366 memcpy(ptr
, string
, slen
);
1370 skb_put(skb
, slen
+ 2); /* don't include null terminator */
1374 * audit_string_contains_control - does a string need to be logged in hex
1375 * @string: string to be checked
1376 * @len: max length of the string to check
1378 int audit_string_contains_control(const char *string
, size_t len
)
1380 const unsigned char *p
;
1381 for (p
= string
; p
< (const unsigned char *)string
+ len
; p
++) {
1382 if (*p
== '"' || *p
< 0x21 || *p
> 0x7e)
1389 * audit_log_n_untrustedstring - log a string that may contain random characters
1391 * @len: length of string (not including trailing null)
1392 * @string: string to be logged
1394 * This code will escape a string that is passed to it if the string
1395 * contains a control character, unprintable character, double quote mark,
1396 * or a space. Unescaped strings will start and end with a double quote mark.
1397 * Strings that are escaped are printed in hex (2 digits per char).
1399 * The caller specifies the number of characters in the string to log, which may
1400 * or may not be the entire string.
1402 void audit_log_n_untrustedstring(struct audit_buffer
*ab
, const char *string
,
1405 if (audit_string_contains_control(string
, len
))
1406 audit_log_n_hex(ab
, string
, len
);
1408 audit_log_n_string(ab
, string
, len
);
1412 * audit_log_untrustedstring - log a string that may contain random characters
1414 * @string: string to be logged
1416 * Same as audit_log_n_untrustedstring(), except that strlen is used to
1417 * determine string length.
1419 void audit_log_untrustedstring(struct audit_buffer
*ab
, const char *string
)
1421 audit_log_n_untrustedstring(ab
, string
, strlen(string
));
1424 /* This is a helper-function to print the escaped d_path */
1425 void audit_log_d_path(struct audit_buffer
*ab
, const char *prefix
,
1426 const struct path
*path
)
1431 audit_log_format(ab
, "%s", prefix
);
1433 /* We will allow 11 spaces for ' (deleted)' to be appended */
1434 pathname
= kmalloc(PATH_MAX
+11, ab
->gfp_mask
);
1436 audit_log_string(ab
, "<no_memory>");
1439 p
= d_path(path
, pathname
, PATH_MAX
+11);
1440 if (IS_ERR(p
)) { /* Should never happen since we send PATH_MAX */
1441 /* FIXME: can we save some information here? */
1442 audit_log_string(ab
, "<too_long>");
1444 audit_log_untrustedstring(ab
, p
);
1448 void audit_log_key(struct audit_buffer
*ab
, char *key
)
1450 audit_log_format(ab
, " key=");
1452 audit_log_untrustedstring(ab
, key
);
1454 audit_log_format(ab
, "(null)");
1458 * audit_log_link_denied - report a link restriction denial
1459 * @operation: specific link opreation
1460 * @link: the path that triggered the restriction
1462 void audit_log_link_denied(const char *operation
, struct path
*link
)
1464 struct audit_buffer
*ab
;
1466 ab
= audit_log_start(current
->audit_context
, GFP_KERNEL
,
1468 audit_log_format(ab
, "op=%s action=denied", operation
);
1469 audit_log_format(ab
, " pid=%d comm=", current
->pid
);
1470 audit_log_untrustedstring(ab
, current
->comm
);
1471 audit_log_d_path(ab
, " path=", link
);
1472 audit_log_format(ab
, " dev=");
1473 audit_log_untrustedstring(ab
, link
->dentry
->d_inode
->i_sb
->s_id
);
1474 audit_log_format(ab
, " ino=%lu", link
->dentry
->d_inode
->i_ino
);
1479 * audit_log_end - end one audit record
1480 * @ab: the audit_buffer
1482 * The netlink_* functions cannot be called inside an irq context, so
1483 * the audit buffer is placed on a queue and a tasklet is scheduled to
1484 * remove them from the queue outside the irq context. May be called in
1487 void audit_log_end(struct audit_buffer
*ab
)
1491 if (!audit_rate_check()) {
1492 audit_log_lost("rate limit exceeded");
1494 struct nlmsghdr
*nlh
= nlmsg_hdr(ab
->skb
);
1495 nlh
->nlmsg_len
= ab
->skb
->len
- NLMSG_SPACE(0);
1498 skb_queue_tail(&audit_skb_queue
, ab
->skb
);
1499 wake_up_interruptible(&kauditd_wait
);
1501 audit_printk_skb(ab
->skb
);
1505 audit_buffer_free(ab
);
1509 * audit_log - Log an audit record
1510 * @ctx: audit context
1511 * @gfp_mask: type of allocation
1512 * @type: audit message type
1513 * @fmt: format string to use
1514 * @...: variable parameters matching the format string
1516 * This is a convenience function that calls audit_log_start,
1517 * audit_log_vformat, and audit_log_end. It may be called
1520 void audit_log(struct audit_context
*ctx
, gfp_t gfp_mask
, int type
,
1521 const char *fmt
, ...)
1523 struct audit_buffer
*ab
;
1526 ab
= audit_log_start(ctx
, gfp_mask
, type
);
1528 va_start(args
, fmt
);
1529 audit_log_vformat(ab
, fmt
, args
);
1535 #ifdef CONFIG_SECURITY
1537 * audit_log_secctx - Converts and logs SELinux context
1539 * @secid: security number
1541 * This is a helper function that calls security_secid_to_secctx to convert
1542 * secid to secctx and then adds the (converted) SELinux context to the audit
1543 * log by calling audit_log_format, thus also preventing leak of internal secid
1544 * to userspace. If secid cannot be converted audit_panic is called.
1546 void audit_log_secctx(struct audit_buffer
*ab
, u32 secid
)
1551 if (security_secid_to_secctx(secid
, &secctx
, &len
)) {
1552 audit_panic("Cannot convert secid to context");
1554 audit_log_format(ab
, " obj=%s", secctx
);
1555 security_release_secctx(secctx
, len
);
1558 EXPORT_SYMBOL(audit_log_secctx
);
1561 EXPORT_SYMBOL(audit_log_start
);
1562 EXPORT_SYMBOL(audit_log_end
);
1563 EXPORT_SYMBOL(audit_log_format
);
1564 EXPORT_SYMBOL(audit_log
);