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 /* Hash for inode-based rules */
119 struct list_head audit_inode_hash
[AUDIT_INODE_BUCKETS
];
121 /* The audit_freelist is a list of pre-allocated audit buffers (if more
122 * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
123 * being placed on the freelist). */
124 static DEFINE_SPINLOCK(audit_freelist_lock
);
125 static int audit_freelist_count
;
126 static LIST_HEAD(audit_freelist
);
128 static struct sk_buff_head audit_skb_queue
;
129 /* queue of skbs to send to auditd when/if it comes back */
130 static struct sk_buff_head audit_skb_hold_queue
;
131 static struct task_struct
*kauditd_task
;
132 static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait
);
133 static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait
);
135 /* Serialize requests from userspace. */
136 static DEFINE_MUTEX(audit_cmd_mutex
);
138 /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
139 * audit records. Since printk uses a 1024 byte buffer, this buffer
140 * should be at least that large. */
141 #define AUDIT_BUFSIZ 1024
143 /* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the
144 * audit_freelist. Doing so eliminates many kmalloc/kfree calls. */
145 #define AUDIT_MAXFREE (2*NR_CPUS)
147 /* The audit_buffer is used when formatting an audit record. The caller
148 * locks briefly to get the record off the freelist or to allocate the
149 * buffer, and locks briefly to send the buffer to the netlink layer or
150 * to place it on a transmit queue. Multiple audit_buffers can be in
151 * use simultaneously. */
152 struct audit_buffer
{
153 struct list_head list
;
154 struct sk_buff
*skb
; /* formatted skb ready to send */
155 struct audit_context
*ctx
; /* NULL or associated context */
164 static void audit_set_pid(struct audit_buffer
*ab
, pid_t pid
)
167 struct nlmsghdr
*nlh
= nlmsg_hdr(ab
->skb
);
168 nlh
->nlmsg_pid
= pid
;
172 void audit_panic(const char *message
)
174 switch (audit_failure
)
176 case AUDIT_FAIL_SILENT
:
178 case AUDIT_FAIL_PRINTK
:
179 if (printk_ratelimit())
180 printk(KERN_ERR
"audit: %s\n", message
);
182 case AUDIT_FAIL_PANIC
:
183 /* test audit_pid since printk is always losey, why bother? */
185 panic("audit: %s\n", message
);
190 static inline int audit_rate_check(void)
192 static unsigned long last_check
= 0;
193 static int messages
= 0;
194 static DEFINE_SPINLOCK(lock
);
197 unsigned long elapsed
;
200 if (!audit_rate_limit
) return 1;
202 spin_lock_irqsave(&lock
, flags
);
203 if (++messages
< audit_rate_limit
) {
207 elapsed
= now
- last_check
;
214 spin_unlock_irqrestore(&lock
, flags
);
220 * audit_log_lost - conditionally log lost audit message event
221 * @message: the message stating reason for lost audit message
223 * Emit at least 1 message per second, even if audit_rate_check is
225 * Always increment the lost messages counter.
227 void audit_log_lost(const char *message
)
229 static unsigned long last_msg
= 0;
230 static DEFINE_SPINLOCK(lock
);
235 atomic_inc(&audit_lost
);
237 print
= (audit_failure
== AUDIT_FAIL_PANIC
|| !audit_rate_limit
);
240 spin_lock_irqsave(&lock
, flags
);
242 if (now
- last_msg
> HZ
) {
246 spin_unlock_irqrestore(&lock
, flags
);
250 if (printk_ratelimit())
252 "audit: audit_lost=%d audit_rate_limit=%d "
253 "audit_backlog_limit=%d\n",
254 atomic_read(&audit_lost
),
256 audit_backlog_limit
);
257 audit_panic(message
);
261 static int audit_log_config_change(char *function_name
, int new, int old
,
262 uid_t loginuid
, u32 sessionid
, u32 sid
,
265 struct audit_buffer
*ab
;
268 ab
= audit_log_start(NULL
, GFP_KERNEL
, AUDIT_CONFIG_CHANGE
);
269 audit_log_format(ab
, "%s=%d old=%d auid=%u ses=%u", function_name
, new,
270 old
, loginuid
, sessionid
);
275 rc
= security_secid_to_secctx(sid
, &ctx
, &len
);
277 audit_log_format(ab
, " sid=%u", sid
);
278 allow_changes
= 0; /* Something weird, deny request */
280 audit_log_format(ab
, " subj=%s", ctx
);
281 security_release_secctx(ctx
, len
);
284 audit_log_format(ab
, " res=%d", allow_changes
);
289 static int audit_do_config_change(char *function_name
, int *to_change
,
290 int new, uid_t loginuid
, u32 sessionid
,
293 int allow_changes
, rc
= 0, old
= *to_change
;
295 /* check if we are locked */
296 if (audit_enabled
== AUDIT_LOCKED
)
301 if (audit_enabled
!= AUDIT_OFF
) {
302 rc
= audit_log_config_change(function_name
, new, old
, loginuid
,
303 sessionid
, sid
, allow_changes
);
308 /* If we are allowed, make the change */
309 if (allow_changes
== 1)
311 /* Not allowed, update reason */
317 static int audit_set_rate_limit(int limit
, uid_t loginuid
, u32 sessionid
,
320 return audit_do_config_change("audit_rate_limit", &audit_rate_limit
,
321 limit
, loginuid
, sessionid
, sid
);
324 static int audit_set_backlog_limit(int limit
, uid_t loginuid
, u32 sessionid
,
327 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit
,
328 limit
, loginuid
, sessionid
, sid
);
331 static int audit_set_enabled(int state
, uid_t loginuid
, u32 sessionid
, u32 sid
)
334 if (state
< AUDIT_OFF
|| state
> AUDIT_LOCKED
)
337 rc
= audit_do_config_change("audit_enabled", &audit_enabled
, state
,
338 loginuid
, sessionid
, sid
);
341 audit_ever_enabled
|= !!state
;
346 static int audit_set_failure(int state
, uid_t loginuid
, u32 sessionid
, u32 sid
)
348 if (state
!= AUDIT_FAIL_SILENT
349 && state
!= AUDIT_FAIL_PRINTK
350 && state
!= AUDIT_FAIL_PANIC
)
353 return audit_do_config_change("audit_failure", &audit_failure
, state
,
354 loginuid
, sessionid
, sid
);
358 * Queue skbs to be sent to auditd when/if it comes back. These skbs should
359 * already have been sent via prink/syslog and so if these messages are dropped
360 * it is not a huge concern since we already passed the audit_log_lost()
361 * notification and stuff. This is just nice to get audit messages during
362 * boot before auditd is running or messages generated while auditd is stopped.
363 * This only holds messages is audit_default is set, aka booting with audit=1
364 * or building your kernel that way.
366 static void audit_hold_skb(struct sk_buff
*skb
)
369 skb_queue_len(&audit_skb_hold_queue
) < audit_backlog_limit
)
370 skb_queue_tail(&audit_skb_hold_queue
, skb
);
376 * For one reason or another this nlh isn't getting delivered to the userspace
377 * audit daemon, just send it to printk.
379 static void audit_printk_skb(struct sk_buff
*skb
)
381 struct nlmsghdr
*nlh
= nlmsg_hdr(skb
);
382 char *data
= NLMSG_DATA(nlh
);
384 if (nlh
->nlmsg_type
!= AUDIT_EOE
) {
385 if (printk_ratelimit())
386 printk(KERN_NOTICE
"type=%d %s\n", nlh
->nlmsg_type
, data
);
388 audit_log_lost("printk limit exceeded\n");
394 static void kauditd_send_skb(struct sk_buff
*skb
)
397 /* take a reference in case we can't send it and we want to hold it */
399 err
= netlink_unicast(audit_sock
, skb
, audit_nlk_pid
, 0);
401 BUG_ON(err
!= -ECONNREFUSED
); /* Shoudn't happen */
402 printk(KERN_ERR
"audit: *NO* daemon at audit_pid=%d\n", audit_pid
);
403 audit_log_lost("auditd dissapeared\n");
405 /* we might get lucky and get this in the next auditd */
408 /* drop the extra reference if sent ok */
412 static int kauditd_thread(void *dummy
)
417 while (!kthread_should_stop()) {
419 * if auditd just started drain the queue of messages already
420 * sent to syslog/printk. remember loss here is ok. we already
421 * called audit_log_lost() if it didn't go out normally. so the
422 * race between the skb_dequeue and the next check for audit_pid
425 * if you ever find kauditd to be too slow we can get a perf win
426 * by doing our own locking and keeping better track if there
427 * are messages in this queue. I don't see the need now, but
428 * in 5 years when I want to play with this again I'll see this
429 * note and still have no friggin idea what i'm thinking today.
431 if (audit_default
&& audit_pid
) {
432 skb
= skb_dequeue(&audit_skb_hold_queue
);
434 while (skb
&& audit_pid
) {
435 kauditd_send_skb(skb
);
436 skb
= skb_dequeue(&audit_skb_hold_queue
);
441 skb
= skb_dequeue(&audit_skb_queue
);
442 wake_up(&audit_backlog_wait
);
445 kauditd_send_skb(skb
);
447 audit_printk_skb(skb
);
449 DECLARE_WAITQUEUE(wait
, current
);
450 set_current_state(TASK_INTERRUPTIBLE
);
451 add_wait_queue(&kauditd_wait
, &wait
);
453 if (!skb_queue_len(&audit_skb_queue
)) {
458 __set_current_state(TASK_RUNNING
);
459 remove_wait_queue(&kauditd_wait
, &wait
);
465 static int audit_prepare_user_tty(pid_t pid
, uid_t loginuid
, u32 sessionid
)
467 struct task_struct
*tsk
;
470 read_lock(&tasklist_lock
);
471 tsk
= find_task_by_vpid(pid
);
477 spin_lock_irq(&tsk
->sighand
->siglock
);
478 if (!tsk
->signal
->audit_tty
)
480 spin_unlock_irq(&tsk
->sighand
->siglock
);
484 tty_audit_push_task(tsk
, loginuid
, sessionid
);
486 read_unlock(&tasklist_lock
);
490 int audit_send_list(void *_dest
)
492 struct audit_netlink_list
*dest
= _dest
;
496 /* wait for parent to finish and send an ACK */
497 mutex_lock(&audit_cmd_mutex
);
498 mutex_unlock(&audit_cmd_mutex
);
500 while ((skb
= __skb_dequeue(&dest
->q
)) != NULL
)
501 netlink_unicast(audit_sock
, skb
, pid
, 0);
508 #ifdef CONFIG_AUDIT_TREE
509 static int prune_tree_thread(void *unused
)
511 mutex_lock(&audit_cmd_mutex
);
513 mutex_unlock(&audit_cmd_mutex
);
517 void audit_schedule_prune(void)
519 kthread_run(prune_tree_thread
, NULL
, "audit_prune_tree");
523 struct sk_buff
*audit_make_reply(int pid
, int seq
, int type
, int done
,
524 int multi
, void *payload
, int size
)
527 struct nlmsghdr
*nlh
;
529 int flags
= multi
? NLM_F_MULTI
: 0;
530 int t
= done
? NLMSG_DONE
: type
;
532 skb
= nlmsg_new(size
, GFP_KERNEL
);
536 nlh
= NLMSG_NEW(skb
, pid
, seq
, t
, size
, flags
);
537 data
= NLMSG_DATA(nlh
);
538 memcpy(data
, payload
, size
);
541 nlmsg_failure
: /* Used by NLMSG_NEW */
547 static int audit_send_reply_thread(void *arg
)
549 struct audit_reply
*reply
= (struct audit_reply
*)arg
;
551 mutex_lock(&audit_cmd_mutex
);
552 mutex_unlock(&audit_cmd_mutex
);
554 /* Ignore failure. It'll only happen if the sender goes away,
555 because our timeout is set to infinite. */
556 netlink_unicast(audit_sock
, reply
->skb
, reply
->pid
, 0);
561 * audit_send_reply - send an audit reply message via netlink
562 * @pid: process id to send reply to
563 * @seq: sequence number
564 * @type: audit message type
565 * @done: done (last) flag
566 * @multi: multi-part message flag
567 * @payload: payload data
568 * @size: payload size
570 * Allocates an skb, builds the netlink message, and sends it to the pid.
571 * No failure notifications.
573 void audit_send_reply(int pid
, int seq
, int type
, int done
, int multi
,
574 void *payload
, int size
)
577 struct task_struct
*tsk
;
578 struct audit_reply
*reply
= kmalloc(sizeof(struct audit_reply
),
584 skb
= audit_make_reply(pid
, seq
, type
, done
, multi
, payload
, size
);
591 tsk
= kthread_run(audit_send_reply_thread
, reply
, "audit_send_reply");
600 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
603 static int audit_netlink_ok(struct sk_buff
*skb
, u16 msg_type
)
610 case AUDIT_LIST_RULES
:
616 case AUDIT_SIGNAL_INFO
:
620 case AUDIT_MAKE_EQUIV
:
621 if (security_netlink_recv(skb
, CAP_AUDIT_CONTROL
))
625 case AUDIT_FIRST_USER_MSG
... AUDIT_LAST_USER_MSG
:
626 case AUDIT_FIRST_USER_MSG2
... AUDIT_LAST_USER_MSG2
:
627 if (security_netlink_recv(skb
, CAP_AUDIT_WRITE
))
630 default: /* bad msg */
637 static int audit_log_common_recv_msg(struct audit_buffer
**ab
, u16 msg_type
,
638 u32 pid
, u32 uid
, uid_t auid
, u32 ses
,
645 if (!audit_enabled
) {
650 *ab
= audit_log_start(NULL
, GFP_KERNEL
, msg_type
);
651 audit_log_format(*ab
, "user pid=%d uid=%u auid=%u ses=%u",
652 pid
, uid
, auid
, ses
);
654 rc
= security_secid_to_secctx(sid
, &ctx
, &len
);
656 audit_log_format(*ab
, " ssid=%u", sid
);
658 audit_log_format(*ab
, " subj=%s", ctx
);
659 security_release_secctx(ctx
, len
);
666 static int audit_receive_msg(struct sk_buff
*skb
, struct nlmsghdr
*nlh
)
668 u32 uid
, pid
, seq
, sid
;
670 struct audit_status
*status_get
, status_set
;
672 struct audit_buffer
*ab
;
673 u16 msg_type
= nlh
->nlmsg_type
;
674 uid_t loginuid
; /* loginuid of sender */
676 struct audit_sig_info
*sig_data
;
680 err
= audit_netlink_ok(skb
, msg_type
);
684 /* As soon as there's any sign of userspace auditd,
685 * start kauditd to talk to it */
687 kauditd_task
= kthread_run(kauditd_thread
, NULL
, "kauditd");
688 if (IS_ERR(kauditd_task
)) {
689 err
= PTR_ERR(kauditd_task
);
694 pid
= NETLINK_CREDS(skb
)->pid
;
695 uid
= NETLINK_CREDS(skb
)->uid
;
696 loginuid
= NETLINK_CB(skb
).loginuid
;
697 sessionid
= NETLINK_CB(skb
).sessionid
;
698 sid
= NETLINK_CB(skb
).sid
;
699 seq
= nlh
->nlmsg_seq
;
700 data
= NLMSG_DATA(nlh
);
704 status_set
.enabled
= audit_enabled
;
705 status_set
.failure
= audit_failure
;
706 status_set
.pid
= audit_pid
;
707 status_set
.rate_limit
= audit_rate_limit
;
708 status_set
.backlog_limit
= audit_backlog_limit
;
709 status_set
.lost
= atomic_read(&audit_lost
);
710 status_set
.backlog
= skb_queue_len(&audit_skb_queue
);
711 audit_send_reply(NETLINK_CB(skb
).pid
, seq
, AUDIT_GET
, 0, 0,
712 &status_set
, sizeof(status_set
));
715 if (nlh
->nlmsg_len
< sizeof(struct audit_status
))
717 status_get
= (struct audit_status
*)data
;
718 if (status_get
->mask
& AUDIT_STATUS_ENABLED
) {
719 err
= audit_set_enabled(status_get
->enabled
,
720 loginuid
, sessionid
, sid
);
724 if (status_get
->mask
& AUDIT_STATUS_FAILURE
) {
725 err
= audit_set_failure(status_get
->failure
,
726 loginuid
, sessionid
, sid
);
730 if (status_get
->mask
& AUDIT_STATUS_PID
) {
731 int new_pid
= status_get
->pid
;
733 if (audit_enabled
!= AUDIT_OFF
)
734 audit_log_config_change("audit_pid", new_pid
,
739 audit_nlk_pid
= NETLINK_CB(skb
).pid
;
741 if (status_get
->mask
& AUDIT_STATUS_RATE_LIMIT
) {
742 err
= audit_set_rate_limit(status_get
->rate_limit
,
743 loginuid
, sessionid
, sid
);
747 if (status_get
->mask
& AUDIT_STATUS_BACKLOG_LIMIT
)
748 err
= audit_set_backlog_limit(status_get
->backlog_limit
,
749 loginuid
, sessionid
, sid
);
752 case AUDIT_FIRST_USER_MSG
... AUDIT_LAST_USER_MSG
:
753 case AUDIT_FIRST_USER_MSG2
... AUDIT_LAST_USER_MSG2
:
754 if (!audit_enabled
&& msg_type
!= AUDIT_USER_AVC
)
757 err
= audit_filter_user(&NETLINK_CB(skb
));
760 if (msg_type
== AUDIT_USER_TTY
) {
761 err
= audit_prepare_user_tty(pid
, loginuid
,
766 audit_log_common_recv_msg(&ab
, msg_type
, pid
, uid
,
767 loginuid
, sessionid
, sid
);
769 if (msg_type
!= AUDIT_USER_TTY
)
770 audit_log_format(ab
, " msg='%.1024s'",
775 audit_log_format(ab
, " msg=");
776 size
= nlmsg_len(nlh
);
778 ((unsigned char *)data
)[size
- 1] == '\0')
780 audit_log_n_untrustedstring(ab
, data
, size
);
782 audit_set_pid(ab
, pid
);
788 if (nlmsg_len(nlh
) < sizeof(struct audit_rule
))
790 if (audit_enabled
== AUDIT_LOCKED
) {
791 audit_log_common_recv_msg(&ab
, AUDIT_CONFIG_CHANGE
, pid
,
792 uid
, loginuid
, sessionid
, sid
);
794 audit_log_format(ab
, " audit_enabled=%d res=0",
801 err
= audit_receive_filter(msg_type
, NETLINK_CB(skb
).pid
,
802 uid
, seq
, data
, nlmsg_len(nlh
),
803 loginuid
, sessionid
, sid
);
807 if (nlmsg_len(nlh
) < sizeof(struct audit_rule_data
))
809 if (audit_enabled
== AUDIT_LOCKED
) {
810 audit_log_common_recv_msg(&ab
, AUDIT_CONFIG_CHANGE
, pid
,
811 uid
, loginuid
, sessionid
, sid
);
813 audit_log_format(ab
, " audit_enabled=%d res=0",
819 case AUDIT_LIST_RULES
:
820 err
= audit_receive_filter(msg_type
, NETLINK_CB(skb
).pid
,
821 uid
, seq
, data
, nlmsg_len(nlh
),
822 loginuid
, sessionid
, sid
);
827 audit_log_common_recv_msg(&ab
, AUDIT_CONFIG_CHANGE
, pid
,
828 uid
, loginuid
, sessionid
, sid
);
830 audit_log_format(ab
, " op=trim res=1");
833 case AUDIT_MAKE_EQUIV
: {
836 size_t msglen
= nlmsg_len(nlh
);
840 if (msglen
< 2 * sizeof(u32
))
842 memcpy(sizes
, bufp
, 2 * sizeof(u32
));
843 bufp
+= 2 * sizeof(u32
);
844 msglen
-= 2 * sizeof(u32
);
845 old
= audit_unpack_string(&bufp
, &msglen
, sizes
[0]);
850 new = audit_unpack_string(&bufp
, &msglen
, sizes
[1]);
856 /* OK, here comes... */
857 err
= audit_tag_tree(old
, new);
859 audit_log_common_recv_msg(&ab
, AUDIT_CONFIG_CHANGE
, pid
,
860 uid
, loginuid
, sessionid
, sid
);
862 audit_log_format(ab
, " op=make_equiv old=");
863 audit_log_untrustedstring(ab
, old
);
864 audit_log_format(ab
, " new=");
865 audit_log_untrustedstring(ab
, new);
866 audit_log_format(ab
, " res=%d", !err
);
872 case AUDIT_SIGNAL_INFO
:
873 err
= security_secid_to_secctx(audit_sig_sid
, &ctx
, &len
);
876 sig_data
= kmalloc(sizeof(*sig_data
) + len
, GFP_KERNEL
);
878 security_release_secctx(ctx
, len
);
881 sig_data
->uid
= audit_sig_uid
;
882 sig_data
->pid
= audit_sig_pid
;
883 memcpy(sig_data
->ctx
, ctx
, len
);
884 security_release_secctx(ctx
, len
);
885 audit_send_reply(NETLINK_CB(skb
).pid
, seq
, AUDIT_SIGNAL_INFO
,
886 0, 0, sig_data
, sizeof(*sig_data
) + len
);
889 case AUDIT_TTY_GET
: {
890 struct audit_tty_status s
;
891 struct task_struct
*tsk
;
893 read_lock(&tasklist_lock
);
894 tsk
= find_task_by_vpid(pid
);
898 spin_lock_irq(&tsk
->sighand
->siglock
);
899 s
.enabled
= tsk
->signal
->audit_tty
!= 0;
900 spin_unlock_irq(&tsk
->sighand
->siglock
);
902 read_unlock(&tasklist_lock
);
903 audit_send_reply(NETLINK_CB(skb
).pid
, seq
, AUDIT_TTY_GET
, 0, 0,
907 case AUDIT_TTY_SET
: {
908 struct audit_tty_status
*s
;
909 struct task_struct
*tsk
;
911 if (nlh
->nlmsg_len
< sizeof(struct audit_tty_status
))
914 if (s
->enabled
!= 0 && s
->enabled
!= 1)
916 read_lock(&tasklist_lock
);
917 tsk
= find_task_by_vpid(pid
);
921 spin_lock_irq(&tsk
->sighand
->siglock
);
922 tsk
->signal
->audit_tty
= s
->enabled
!= 0;
923 spin_unlock_irq(&tsk
->sighand
->siglock
);
925 read_unlock(&tasklist_lock
);
933 return err
< 0 ? err
: 0;
937 * Get message from skb. Each message is processed by audit_receive_msg.
938 * Malformed skbs with wrong length are discarded silently.
940 static void audit_receive_skb(struct sk_buff
*skb
)
942 struct nlmsghdr
*nlh
;
944 * len MUST be signed for NLMSG_NEXT to be able to dec it below 0
945 * if the nlmsg_len was not aligned
950 nlh
= nlmsg_hdr(skb
);
953 while (NLMSG_OK(nlh
, len
)) {
954 err
= audit_receive_msg(skb
, nlh
);
955 /* if err or if this message says it wants a response */
956 if (err
|| (nlh
->nlmsg_flags
& NLM_F_ACK
))
957 netlink_ack(skb
, nlh
, err
);
959 nlh
= NLMSG_NEXT(nlh
, len
);
963 /* Receive messages from netlink socket. */
964 static void audit_receive(struct sk_buff
*skb
)
966 mutex_lock(&audit_cmd_mutex
);
967 audit_receive_skb(skb
);
968 mutex_unlock(&audit_cmd_mutex
);
971 /* Initialize audit support at boot time. */
972 static int __init
audit_init(void)
976 if (audit_initialized
== AUDIT_DISABLED
)
979 printk(KERN_INFO
"audit: initializing netlink socket (%s)\n",
980 audit_default
? "enabled" : "disabled");
981 audit_sock
= netlink_kernel_create(&init_net
, NETLINK_AUDIT
, 0,
982 audit_receive
, NULL
, THIS_MODULE
);
984 audit_panic("cannot initialize netlink socket");
986 audit_sock
->sk_sndtimeo
= MAX_SCHEDULE_TIMEOUT
;
988 skb_queue_head_init(&audit_skb_queue
);
989 skb_queue_head_init(&audit_skb_hold_queue
);
990 audit_initialized
= AUDIT_INITIALIZED
;
991 audit_enabled
= audit_default
;
992 audit_ever_enabled
|= !!audit_default
;
994 audit_log(NULL
, GFP_KERNEL
, AUDIT_KERNEL
, "initialized");
996 for (i
= 0; i
< AUDIT_INODE_BUCKETS
; i
++)
997 INIT_LIST_HEAD(&audit_inode_hash
[i
]);
1001 __initcall(audit_init
);
1003 /* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
1004 static int __init
audit_enable(char *str
)
1006 audit_default
= !!simple_strtol(str
, NULL
, 0);
1008 audit_initialized
= AUDIT_DISABLED
;
1010 printk(KERN_INFO
"audit: %s", audit_default
? "enabled" : "disabled");
1012 if (audit_initialized
== AUDIT_INITIALIZED
) {
1013 audit_enabled
= audit_default
;
1014 audit_ever_enabled
|= !!audit_default
;
1015 } else if (audit_initialized
== AUDIT_UNINITIALIZED
) {
1016 printk(" (after initialization)");
1018 printk(" (until reboot)");
1025 __setup("audit=", audit_enable
);
1027 static void audit_buffer_free(struct audit_buffer
*ab
)
1029 unsigned long flags
;
1037 spin_lock_irqsave(&audit_freelist_lock
, flags
);
1038 if (audit_freelist_count
> AUDIT_MAXFREE
)
1041 audit_freelist_count
++;
1042 list_add(&ab
->list
, &audit_freelist
);
1044 spin_unlock_irqrestore(&audit_freelist_lock
, flags
);
1047 static struct audit_buffer
* audit_buffer_alloc(struct audit_context
*ctx
,
1048 gfp_t gfp_mask
, int type
)
1050 unsigned long flags
;
1051 struct audit_buffer
*ab
= NULL
;
1052 struct nlmsghdr
*nlh
;
1054 spin_lock_irqsave(&audit_freelist_lock
, flags
);
1055 if (!list_empty(&audit_freelist
)) {
1056 ab
= list_entry(audit_freelist
.next
,
1057 struct audit_buffer
, list
);
1058 list_del(&ab
->list
);
1059 --audit_freelist_count
;
1061 spin_unlock_irqrestore(&audit_freelist_lock
, flags
);
1064 ab
= kmalloc(sizeof(*ab
), gfp_mask
);
1070 ab
->gfp_mask
= gfp_mask
;
1072 ab
->skb
= nlmsg_new(AUDIT_BUFSIZ
, gfp_mask
);
1076 nlh
= NLMSG_NEW(ab
->skb
, 0, 0, type
, 0, 0);
1080 nlmsg_failure
: /* Used by NLMSG_NEW */
1084 audit_buffer_free(ab
);
1089 * audit_serial - compute a serial number for the audit record
1091 * Compute a serial number for the audit record. Audit records are
1092 * written to user-space as soon as they are generated, so a complete
1093 * audit record may be written in several pieces. The timestamp of the
1094 * record and this serial number are used by the user-space tools to
1095 * determine which pieces belong to the same audit record. The
1096 * (timestamp,serial) tuple is unique for each syscall and is live from
1097 * syscall entry to syscall exit.
1099 * NOTE: Another possibility is to store the formatted records off the
1100 * audit context (for those records that have a context), and emit them
1101 * all at syscall exit. However, this could delay the reporting of
1102 * significant errors until syscall exit (or never, if the system
1105 unsigned int audit_serial(void)
1107 static DEFINE_SPINLOCK(serial_lock
);
1108 static unsigned int serial
= 0;
1110 unsigned long flags
;
1113 spin_lock_irqsave(&serial_lock
, flags
);
1116 } while (unlikely(!ret
));
1117 spin_unlock_irqrestore(&serial_lock
, flags
);
1122 static inline void audit_get_stamp(struct audit_context
*ctx
,
1123 struct timespec
*t
, unsigned int *serial
)
1125 if (!ctx
|| !auditsc_get_stamp(ctx
, t
, serial
)) {
1127 *serial
= audit_serial();
1131 /* Obtain an audit buffer. This routine does locking to obtain the
1132 * audit buffer, but then no locking is required for calls to
1133 * audit_log_*format. If the tsk is a task that is currently in a
1134 * syscall, then the syscall is marked as auditable and an audit record
1135 * will be written at syscall exit. If there is no associated task, tsk
1136 * should be NULL. */
1139 * audit_log_start - obtain an audit buffer
1140 * @ctx: audit_context (may be NULL)
1141 * @gfp_mask: type of allocation
1142 * @type: audit message type
1144 * Returns audit_buffer pointer on success or NULL on error.
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 task (ctx) 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, then
1151 * task context (ctx) should be NULL.
1153 struct audit_buffer
*audit_log_start(struct audit_context
*ctx
, gfp_t gfp_mask
,
1156 struct audit_buffer
*ab
= NULL
;
1158 unsigned int uninitialized_var(serial
);
1160 unsigned long timeout_start
= jiffies
;
1162 if (audit_initialized
!= AUDIT_INITIALIZED
)
1165 if (unlikely(audit_filter_type(type
)))
1168 if (gfp_mask
& __GFP_WAIT
)
1171 reserve
= 5; /* Allow atomic callers to go up to five
1172 entries over the normal backlog limit */
1174 while (audit_backlog_limit
1175 && skb_queue_len(&audit_skb_queue
) > audit_backlog_limit
+ reserve
) {
1176 if (gfp_mask
& __GFP_WAIT
&& audit_backlog_wait_time
1177 && time_before(jiffies
, timeout_start
+ audit_backlog_wait_time
)) {
1179 /* Wait for auditd to drain the queue a little */
1180 DECLARE_WAITQUEUE(wait
, current
);
1181 set_current_state(TASK_INTERRUPTIBLE
);
1182 add_wait_queue(&audit_backlog_wait
, &wait
);
1184 if (audit_backlog_limit
&&
1185 skb_queue_len(&audit_skb_queue
) > audit_backlog_limit
)
1186 schedule_timeout(timeout_start
+ audit_backlog_wait_time
- jiffies
);
1188 __set_current_state(TASK_RUNNING
);
1189 remove_wait_queue(&audit_backlog_wait
, &wait
);
1192 if (audit_rate_check() && printk_ratelimit())
1194 "audit: audit_backlog=%d > "
1195 "audit_backlog_limit=%d\n",
1196 skb_queue_len(&audit_skb_queue
),
1197 audit_backlog_limit
);
1198 audit_log_lost("backlog limit exceeded");
1199 audit_backlog_wait_time
= audit_backlog_wait_overflow
;
1200 wake_up(&audit_backlog_wait
);
1204 ab
= audit_buffer_alloc(ctx
, gfp_mask
, type
);
1206 audit_log_lost("out of memory in audit_log_start");
1210 audit_get_stamp(ab
->ctx
, &t
, &serial
);
1212 audit_log_format(ab
, "audit(%lu.%03lu:%u): ",
1213 t
.tv_sec
, t
.tv_nsec
/1000000, serial
);
1218 * audit_expand - expand skb in the audit buffer
1220 * @extra: space to add at tail of the skb
1222 * Returns 0 (no space) on failed expansion, or available space if
1225 static inline int audit_expand(struct audit_buffer
*ab
, int extra
)
1227 struct sk_buff
*skb
= ab
->skb
;
1228 int oldtail
= skb_tailroom(skb
);
1229 int ret
= pskb_expand_head(skb
, 0, extra
, ab
->gfp_mask
);
1230 int newtail
= skb_tailroom(skb
);
1233 audit_log_lost("out of memory in audit_expand");
1237 skb
->truesize
+= newtail
- oldtail
;
1242 * Format an audit message into the audit buffer. If there isn't enough
1243 * room in the audit buffer, more room will be allocated and vsnprint
1244 * will be called a second time. Currently, we assume that a printk
1245 * can't format message larger than 1024 bytes, so we don't either.
1247 static void audit_log_vformat(struct audit_buffer
*ab
, const char *fmt
,
1251 struct sk_buff
*skb
;
1259 avail
= skb_tailroom(skb
);
1261 avail
= audit_expand(ab
, AUDIT_BUFSIZ
);
1265 va_copy(args2
, args
);
1266 len
= vsnprintf(skb_tail_pointer(skb
), avail
, fmt
, args
);
1268 /* The printk buffer is 1024 bytes long, so if we get
1269 * here and AUDIT_BUFSIZ is at least 1024, then we can
1270 * log everything that printk could have logged. */
1271 avail
= audit_expand(ab
,
1272 max_t(unsigned, AUDIT_BUFSIZ
, 1+len
-avail
));
1275 len
= vsnprintf(skb_tail_pointer(skb
), avail
, fmt
, args2
);
1285 * audit_log_format - format a message into the audit buffer.
1287 * @fmt: format string
1288 * @...: optional parameters matching @fmt string
1290 * All the work is done in audit_log_vformat.
1292 void audit_log_format(struct audit_buffer
*ab
, const char *fmt
, ...)
1298 va_start(args
, fmt
);
1299 audit_log_vformat(ab
, fmt
, args
);
1304 * audit_log_hex - convert a buffer to hex and append it to the audit skb
1305 * @ab: the audit_buffer
1306 * @buf: buffer to convert to hex
1307 * @len: length of @buf to be converted
1309 * No return value; failure to expand is silently ignored.
1311 * This function will take the passed buf and convert it into a string of
1312 * ascii hex digits. The new string is placed onto the skb.
1314 void audit_log_n_hex(struct audit_buffer
*ab
, const unsigned char *buf
,
1317 int i
, avail
, new_len
;
1319 struct sk_buff
*skb
;
1320 static const unsigned char *hex
= "0123456789ABCDEF";
1327 avail
= skb_tailroom(skb
);
1329 if (new_len
>= avail
) {
1330 /* Round the buffer request up to the next multiple */
1331 new_len
= AUDIT_BUFSIZ
*(((new_len
-avail
)/AUDIT_BUFSIZ
) + 1);
1332 avail
= audit_expand(ab
, new_len
);
1337 ptr
= skb_tail_pointer(skb
);
1338 for (i
=0; i
<len
; i
++) {
1339 *ptr
++ = hex
[(buf
[i
] & 0xF0)>>4]; /* Upper nibble */
1340 *ptr
++ = hex
[buf
[i
] & 0x0F]; /* Lower nibble */
1343 skb_put(skb
, len
<< 1); /* new string is twice the old string */
1347 * Format a string of no more than slen characters into the audit buffer,
1348 * enclosed in quote marks.
1350 void audit_log_n_string(struct audit_buffer
*ab
, const char *string
,
1355 struct sk_buff
*skb
;
1362 avail
= skb_tailroom(skb
);
1363 new_len
= slen
+ 3; /* enclosing quotes + null terminator */
1364 if (new_len
> avail
) {
1365 avail
= audit_expand(ab
, new_len
);
1369 ptr
= skb_tail_pointer(skb
);
1371 memcpy(ptr
, string
, slen
);
1375 skb_put(skb
, slen
+ 2); /* don't include null terminator */
1379 * audit_string_contains_control - does a string need to be logged in hex
1380 * @string: string to be checked
1381 * @len: max length of the string to check
1383 int audit_string_contains_control(const char *string
, size_t len
)
1385 const unsigned char *p
;
1386 for (p
= string
; p
< (const unsigned char *)string
+ len
; p
++) {
1387 if (*p
== '"' || *p
< 0x21 || *p
> 0x7e)
1394 * audit_log_n_untrustedstring - log a string that may contain random characters
1396 * @len: length of string (not including trailing null)
1397 * @string: string to be logged
1399 * This code will escape a string that is passed to it if the string
1400 * contains a control character, unprintable character, double quote mark,
1401 * or a space. Unescaped strings will start and end with a double quote mark.
1402 * Strings that are escaped are printed in hex (2 digits per char).
1404 * The caller specifies the number of characters in the string to log, which may
1405 * or may not be the entire string.
1407 void audit_log_n_untrustedstring(struct audit_buffer
*ab
, const char *string
,
1410 if (audit_string_contains_control(string
, len
))
1411 audit_log_n_hex(ab
, string
, len
);
1413 audit_log_n_string(ab
, string
, len
);
1417 * audit_log_untrustedstring - log a string that may contain random characters
1419 * @string: string to be logged
1421 * Same as audit_log_n_untrustedstring(), except that strlen is used to
1422 * determine string length.
1424 void audit_log_untrustedstring(struct audit_buffer
*ab
, const char *string
)
1426 audit_log_n_untrustedstring(ab
, string
, strlen(string
));
1429 /* This is a helper-function to print the escaped d_path */
1430 void audit_log_d_path(struct audit_buffer
*ab
, const char *prefix
,
1436 audit_log_format(ab
, " %s", prefix
);
1438 /* We will allow 11 spaces for ' (deleted)' to be appended */
1439 pathname
= kmalloc(PATH_MAX
+11, ab
->gfp_mask
);
1441 audit_log_string(ab
, "<no_memory>");
1444 p
= d_path(path
, pathname
, PATH_MAX
+11);
1445 if (IS_ERR(p
)) { /* Should never happen since we send PATH_MAX */
1446 /* FIXME: can we save some information here? */
1447 audit_log_string(ab
, "<too_long>");
1449 audit_log_untrustedstring(ab
, p
);
1454 * audit_log_end - end one audit record
1455 * @ab: the audit_buffer
1457 * The netlink_* functions cannot be called inside an irq context, so
1458 * the audit buffer is placed on a queue and a tasklet is scheduled to
1459 * remove them from the queue outside the irq context. May be called in
1462 void audit_log_end(struct audit_buffer
*ab
)
1466 if (!audit_rate_check()) {
1467 audit_log_lost("rate limit exceeded");
1469 struct nlmsghdr
*nlh
= nlmsg_hdr(ab
->skb
);
1470 nlh
->nlmsg_len
= ab
->skb
->len
- NLMSG_SPACE(0);
1473 skb_queue_tail(&audit_skb_queue
, ab
->skb
);
1474 wake_up_interruptible(&kauditd_wait
);
1476 audit_printk_skb(ab
->skb
);
1480 audit_buffer_free(ab
);
1484 * audit_log - Log an audit record
1485 * @ctx: audit context
1486 * @gfp_mask: type of allocation
1487 * @type: audit message type
1488 * @fmt: format string to use
1489 * @...: variable parameters matching the format string
1491 * This is a convenience function that calls audit_log_start,
1492 * audit_log_vformat, and audit_log_end. It may be called
1495 void audit_log(struct audit_context
*ctx
, gfp_t gfp_mask
, int type
,
1496 const char *fmt
, ...)
1498 struct audit_buffer
*ab
;
1501 ab
= audit_log_start(ctx
, gfp_mask
, type
);
1503 va_start(args
, fmt
);
1504 audit_log_vformat(ab
, fmt
, args
);
1510 EXPORT_SYMBOL(audit_log_start
);
1511 EXPORT_SYMBOL(audit_log_end
);
1512 EXPORT_SYMBOL(audit_log_format
);
1513 EXPORT_SYMBOL(audit_log
);