projects/linux·blob v3.6 · refs

1565 lines · 40.9 KiB

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
4 *
5 * Copyright 2003-2007 Red Hat Inc., Durham, North Carolina.
6 * All Rights Reserved.
7 *
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.
12 *
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.
17 *
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
21 *
22 * Written by Rickard E. (Rik) Faith <[email protected]>
23 *
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
29 * generation time):
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
36 * current syscall).
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.
40 *
41 * Example user-space utilities: http://people.redhat.com/sgrubb/audit/
42 */
43
44#include <linux/init.h>
45#include <asm/types.h>
46#include <linux/atomic.h>
47#include <linux/mm.h>
48#include <linux/export.h>
49#include <linux/slab.h>
50#include <linux/err.h>
51#include <linux/kthread.h>
52
53#include <linux/audit.h>
54
55#include <net/sock.h>
56#include <net/netlink.h>
57#include <linux/skbuff.h>
58#ifdef CONFIG_SECURITY
59#include <linux/security.h>
60#endif
61#include <linux/netlink.h>
62#include <linux/freezer.h>
63#include <linux/tty.h>
64
65#include "audit.h"
66
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
72static int audit_initialized;
73
74#define AUDIT_OFF 0
75#define AUDIT_ON 1
76#define AUDIT_LOCKED 2
77int audit_enabled;
78int audit_ever_enabled;
79
80EXPORT_SYMBOL_GPL(audit_enabled);
81
82/* Default state when kernel boots without any parameters. */
83static int audit_default;
84
85/* If auditing cannot proceed, audit_failure selects what happens. */
86static int audit_failure = AUDIT_FAIL_PRINTK;
87
88/*
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_pid contains
91 * the pid to use to send netlink messages to that process.
92 */
93int audit_pid;
94static int audit_nlk_pid;
95
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. */
99static int audit_rate_limit;
100
101/* Number of outstanding audit_buffers allowed. */
102static int audit_backlog_limit = 64;
103static int audit_backlog_wait_time = 60 * HZ;
104static int audit_backlog_wait_overflow = 0;
105
106/* The identity of the user shutting down the audit system. */
107uid_t audit_sig_uid = -1;
108pid_t audit_sig_pid = -1;
109u32 audit_sig_sid = 0;
110
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
117*/
118static atomic_t audit_lost = ATOMIC_INIT(0);
119
120/* The netlink socket. */
121static struct sock *audit_sock;
122
123/* Hash for inode-based rules */
124struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
125
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). */
129static DEFINE_SPINLOCK(audit_freelist_lock);
130static int audit_freelist_count;
131static LIST_HEAD(audit_freelist);
132
133static struct sk_buff_head audit_skb_queue;
134/* queue of skbs to send to auditd when/if it comes back */
135static struct sk_buff_head audit_skb_hold_queue;
136static struct task_struct *kauditd_task;
137static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
138static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
139
140/* Serialize requests from userspace. */
141DEFINE_MUTEX(audit_cmd_mutex);
142
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
147
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)
151
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. */
157struct 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 */
161 gfp_t gfp_mask;
162};
163
164struct audit_reply {
165 int pid;
166 struct sk_buff *skb;
167};
168
169static void audit_set_pid(struct audit_buffer *ab, pid_t pid)
170{
171 if (ab) {
172 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
173 nlh->nlmsg_pid = pid;
174 }
175}
176
177void audit_panic(const char *message)
178{
179 switch (audit_failure)
180 {
181 case AUDIT_FAIL_SILENT:
182 break;
183 case AUDIT_FAIL_PRINTK:
184 if (printk_ratelimit())
185 printk(KERN_ERR "audit: %s\n", message);
186 break;
187 case AUDIT_FAIL_PANIC:
188 /* test audit_pid since printk is always losey, why bother? */
189 if (audit_pid)
190 panic("audit: %s\n", message);
191 break;
192 }
193}
194
195static inline int audit_rate_check(void)
196{
197 static unsigned long last_check = 0;
198 static int messages = 0;
199 static DEFINE_SPINLOCK(lock);
200 unsigned long flags;
201 unsigned long now;
202 unsigned long elapsed;
203 int retval = 0;
204
205 if (!audit_rate_limit) return 1;
206
207 spin_lock_irqsave(&lock, flags);
208 if (++messages < audit_rate_limit) {
209 retval = 1;
210 } else {
211 now = jiffies;
212 elapsed = now - last_check;
213 if (elapsed > HZ) {
214 last_check = now;
215 messages = 0;
216 retval = 1;
217 }
218 }
219 spin_unlock_irqrestore(&lock, flags);
220
221 return retval;
222}
223
224/**
225 * audit_log_lost - conditionally log lost audit message event
226 * @message: the message stating reason for lost audit message
227 *
228 * Emit at least 1 message per second, even if audit_rate_check is
229 * throttling.
230 * Always increment the lost messages counter.
231*/
232void audit_log_lost(const char *message)
233{
234 static unsigned long last_msg = 0;
235 static DEFINE_SPINLOCK(lock);
236 unsigned long flags;
237 unsigned long now;
238 int print;
239
240 atomic_inc(&audit_lost);
241
242 print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
243
244 if (!print) {
245 spin_lock_irqsave(&lock, flags);
246 now = jiffies;
247 if (now - last_msg > HZ) {
248 print = 1;
249 last_msg = now;
250 }
251 spin_unlock_irqrestore(&lock, flags);
252 }
253
254 if (print) {
255 if (printk_ratelimit())
256 printk(KERN_WARNING
257 "audit: audit_lost=%d audit_rate_limit=%d "
258 "audit_backlog_limit=%d\n",
259 atomic_read(&audit_lost),
260 audit_rate_limit,
261 audit_backlog_limit);
262 audit_panic(message);
263 }
264}
265
266static int audit_log_config_change(char *function_name, int new, int old,
267 uid_t loginuid, u32 sessionid, u32 sid,
268 int allow_changes)
269{
270 struct audit_buffer *ab;
271 int rc = 0;
272
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);
276 if (sid) {
277 char *ctx = NULL;
278 u32 len;
279
280 rc = security_secid_to_secctx(sid, &ctx, &len);
281 if (rc) {
282 audit_log_format(ab, " sid=%u", sid);
283 allow_changes = 0; /* Something weird, deny request */
284 } else {
285 audit_log_format(ab, " subj=%s", ctx);
286 security_release_secctx(ctx, len);
287 }
288 }
289 audit_log_format(ab, " res=%d", allow_changes);
290 audit_log_end(ab);
291 return rc;
292}
293
294static int audit_do_config_change(char *function_name, int *to_change,
295 int new, uid_t loginuid, u32 sessionid,
296 u32 sid)
297{
298 int allow_changes, rc = 0, old = *to_change;
299
300 /* check if we are locked */
301 if (audit_enabled == AUDIT_LOCKED)
302 allow_changes = 0;
303 else
304 allow_changes = 1;
305
306 if (audit_enabled != AUDIT_OFF) {
307 rc = audit_log_config_change(function_name, new, old, loginuid,
308 sessionid, sid, allow_changes);
309 if (rc)
310 allow_changes = 0;
311 }
312
313 /* If we are allowed, make the change */
314 if (allow_changes == 1)
315 *to_change = new;
316 /* Not allowed, update reason */
317 else if (rc == 0)
318 rc = -EPERM;
319 return rc;
320}
321
322static int audit_set_rate_limit(int limit, uid_t loginuid, u32 sessionid,
323 u32 sid)
324{
325 return audit_do_config_change("audit_rate_limit", &audit_rate_limit,
326 limit, loginuid, sessionid, sid);
327}
328
329static int audit_set_backlog_limit(int limit, uid_t loginuid, u32 sessionid,
330 u32 sid)
331{
332 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit,
333 limit, loginuid, sessionid, sid);
334}
335
336static int audit_set_enabled(int state, uid_t loginuid, u32 sessionid, u32 sid)
337{
338 int rc;
339 if (state < AUDIT_OFF || state > AUDIT_LOCKED)
340 return -EINVAL;
341
342 rc = audit_do_config_change("audit_enabled", &audit_enabled, state,
343 loginuid, sessionid, sid);
344
345 if (!rc)
346 audit_ever_enabled |= !!state;
347
348 return rc;
349}
350
351static int audit_set_failure(int state, uid_t loginuid, u32 sessionid, u32 sid)
352{
353 if (state != AUDIT_FAIL_SILENT
354 && state != AUDIT_FAIL_PRINTK
355 && state != AUDIT_FAIL_PANIC)
356 return -EINVAL;
357
358 return audit_do_config_change("audit_failure", &audit_failure, state,
359 loginuid, sessionid, sid);
360}
361
362/*
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.
370 */
371static void audit_hold_skb(struct sk_buff *skb)
372{
373 if (audit_default &&
374 skb_queue_len(&audit_skb_hold_queue) < audit_backlog_limit)
375 skb_queue_tail(&audit_skb_hold_queue, skb);
376 else
377 kfree_skb(skb);
378}
379
380/*
381 * For one reason or another this nlh isn't getting delivered to the userspace
382 * audit daemon, just send it to printk.
383 */
384static void audit_printk_skb(struct sk_buff *skb)
385{
386 struct nlmsghdr *nlh = nlmsg_hdr(skb);
387 char *data = nlmsg_data(nlh);
388
389 if (nlh->nlmsg_type != AUDIT_EOE) {
390 if (printk_ratelimit())
391 printk(KERN_NOTICE "type=%d %s\n", nlh->nlmsg_type, data);
392 else
393 audit_log_lost("printk limit exceeded\n");
394 }
395
396 audit_hold_skb(skb);
397}
398
399static void kauditd_send_skb(struct sk_buff *skb)
400{
401 int err;
402 /* take a reference in case we can't send it and we want to hold it */
403 skb_get(skb);
404 err = netlink_unicast(audit_sock, skb, audit_nlk_pid, 0);
405 if (err < 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");
409 audit_pid = 0;
410 /* we might get lucky and get this in the next auditd */
411 audit_hold_skb(skb);
412 } else
413 /* drop the extra reference if sent ok */
414 consume_skb(skb);
415}
416
417static int kauditd_thread(void *dummy)
418{
419 struct sk_buff *skb;
420
421 set_freezable();
422 while (!kthread_should_stop()) {
423 /*
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
428 * doesn't matter.
429 *
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.
435 */
436 if (audit_default && audit_pid) {
437 skb = skb_dequeue(&audit_skb_hold_queue);
438 if (unlikely(skb)) {
439 while (skb && audit_pid) {
440 kauditd_send_skb(skb);
441 skb = skb_dequeue(&audit_skb_hold_queue);
442 }
443 }
444 }
445
446 skb = skb_dequeue(&audit_skb_queue);
447 wake_up(&audit_backlog_wait);
448 if (skb) {
449 if (audit_pid)
450 kauditd_send_skb(skb);
451 else
452 audit_printk_skb(skb);
453 } else {
454 DECLARE_WAITQUEUE(wait, current);
455 set_current_state(TASK_INTERRUPTIBLE);
456 add_wait_queue(&kauditd_wait, &wait);
457
458 if (!skb_queue_len(&audit_skb_queue)) {
459 try_to_freeze();
460 schedule();
461 }
462
463 __set_current_state(TASK_RUNNING);
464 remove_wait_queue(&kauditd_wait, &wait);
465 }
466 }
467 return 0;
468}
469
470static int audit_prepare_user_tty(pid_t pid, uid_t loginuid, u32 sessionid)
471{
472 struct task_struct *tsk;
473 int err;
474
475 rcu_read_lock();
476 tsk = find_task_by_vpid(pid);
477 if (!tsk) {
478 rcu_read_unlock();
479 return -ESRCH;
480 }
481 get_task_struct(tsk);
482 rcu_read_unlock();
483 err = tty_audit_push_task(tsk, loginuid, sessionid);
484 put_task_struct(tsk);
485 return err;
486}
487
488int audit_send_list(void *_dest)
489{
490 struct audit_netlink_list *dest = _dest;
491 int pid = dest->pid;
492 struct sk_buff *skb;
493
494 /* wait for parent to finish and send an ACK */
495 mutex_lock(&audit_cmd_mutex);
496 mutex_unlock(&audit_cmd_mutex);
497
498 while ((skb = __skb_dequeue(&dest->q)) != NULL)
499 netlink_unicast(audit_sock, skb, pid, 0);
500
501 kfree(dest);
502
503 return 0;
504}
505
506struct sk_buff *audit_make_reply(int pid, int seq, int type, int done,
507 int multi, const void *payload, int size)
508{
509 struct sk_buff *skb;
510 struct nlmsghdr *nlh;
511 void *data;
512 int flags = multi ? NLM_F_MULTI : 0;
513 int t = done ? NLMSG_DONE : type;
514
515 skb = nlmsg_new(size, GFP_KERNEL);
516 if (!skb)
517 return NULL;
518
519 nlh = nlmsg_put(skb, pid, seq, t, size, flags);
520 if (!nlh)
521 goto out_kfree_skb;
522 data = nlmsg_data(nlh);
523 memcpy(data, payload, size);
524 return skb;
525
526out_kfree_skb:
527 kfree_skb(skb);
528 return NULL;
529}
530
531static int audit_send_reply_thread(void *arg)
532{
533 struct audit_reply *reply = (struct audit_reply *)arg;
534
535 mutex_lock(&audit_cmd_mutex);
536 mutex_unlock(&audit_cmd_mutex);
537
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);
541 kfree(reply);
542 return 0;
543}
544/**
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
553 *
554 * Allocates an skb, builds the netlink message, and sends it to the pid.
555 * No failure notifications.
556 */
557static void audit_send_reply(int pid, int seq, int type, int done, int multi,
558 const void *payload, int size)
559{
560 struct sk_buff *skb;
561 struct task_struct *tsk;
562 struct audit_reply *reply = kmalloc(sizeof(struct audit_reply),
563 GFP_KERNEL);
564
565 if (!reply)
566 return;
567
568 skb = audit_make_reply(pid, seq, type, done, multi, payload, size);
569 if (!skb)
570 goto out;
571
572 reply->pid = pid;
573 reply->skb = skb;
574
575 tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
576 if (!IS_ERR(tsk))
577 return;
578 kfree_skb(skb);
579out:
580 kfree(reply);
581}
582
583/*
584 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
585 * control messages.
586 */
587static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
588{
589 int err = 0;
590
591 switch (msg_type) {
592 case AUDIT_GET:
593 case AUDIT_LIST:
594 case AUDIT_LIST_RULES:
595 case AUDIT_SET:
596 case AUDIT_ADD:
597 case AUDIT_ADD_RULE:
598 case AUDIT_DEL:
599 case AUDIT_DEL_RULE:
600 case AUDIT_SIGNAL_INFO:
601 case AUDIT_TTY_GET:
602 case AUDIT_TTY_SET:
603 case AUDIT_TRIM:
604 case AUDIT_MAKE_EQUIV:
605 if (!capable(CAP_AUDIT_CONTROL))
606 err = -EPERM;
607 break;
608 case AUDIT_USER:
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))
612 err = -EPERM;
613 break;
614 default: /* bad msg */
615 err = -EINVAL;
616 }
617
618 return err;
619}
620
621static int audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type,
622 u32 pid, u32 uid, uid_t auid, u32 ses,
623 u32 sid)
624{
625 int rc = 0;
626 char *ctx = NULL;
627 u32 len;
628
629 if (!audit_enabled) {
630 *ab = NULL;
631 return rc;
632 }
633
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);
637 if (sid) {
638 rc = security_secid_to_secctx(sid, &ctx, &len);
639 if (rc)
640 audit_log_format(*ab, " ssid=%u", sid);
641 else {
642 audit_log_format(*ab, " subj=%s", ctx);
643 security_release_secctx(ctx, len);
644 }
645 }
646
647 return rc;
648}
649
650static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
651{
652 u32 uid, pid, seq, sid;
653 void *data;
654 struct audit_status *status_get, status_set;
655 int err;
656 struct audit_buffer *ab;
657 u16 msg_type = nlh->nlmsg_type;
658 uid_t loginuid; /* loginuid of sender */
659 u32 sessionid;
660 struct audit_sig_info *sig_data;
661 char *ctx = NULL;
662 u32 len;
663
664 err = audit_netlink_ok(skb, msg_type);
665 if (err)
666 return err;
667
668 /* As soon as there's any sign of userspace auditd,
669 * start kauditd to talk to it */
670 if (!kauditd_task)
671 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
672 if (IS_ERR(kauditd_task)) {
673 err = PTR_ERR(kauditd_task);
674 kauditd_task = NULL;
675 return err;
676 }
677
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);
685
686 switch (msg_type) {
687 case AUDIT_GET:
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).pid, seq, AUDIT_GET, 0, 0,
696 &status_set, sizeof(status_set));
697 break;
698 case AUDIT_SET:
699 if (nlh->nlmsg_len < sizeof(struct audit_status))
700 return -EINVAL;
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);
705 if (err < 0)
706 return err;
707 }
708 if (status_get->mask & AUDIT_STATUS_FAILURE) {
709 err = audit_set_failure(status_get->failure,
710 loginuid, sessionid, sid);
711 if (err < 0)
712 return err;
713 }
714 if (status_get->mask & AUDIT_STATUS_PID) {
715 int new_pid = status_get->pid;
716
717 if (audit_enabled != AUDIT_OFF)
718 audit_log_config_change("audit_pid", new_pid,
719 audit_pid, loginuid,
720 sessionid, sid, 1);
721
722 audit_pid = new_pid;
723 audit_nlk_pid = NETLINK_CB(skb).pid;
724 }
725 if (status_get->mask & AUDIT_STATUS_RATE_LIMIT) {
726 err = audit_set_rate_limit(status_get->rate_limit,
727 loginuid, sessionid, sid);
728 if (err < 0)
729 return err;
730 }
731 if (status_get->mask & AUDIT_STATUS_BACKLOG_LIMIT)
732 err = audit_set_backlog_limit(status_get->backlog_limit,
733 loginuid, sessionid, sid);
734 break;
735 case AUDIT_USER:
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)
739 return 0;
740
741 err = audit_filter_user(&NETLINK_CB(skb));
742 if (err == 1) {
743 err = 0;
744 if (msg_type == AUDIT_USER_TTY) {
745 err = audit_prepare_user_tty(pid, loginuid,
746 sessionid);
747 if (err)
748 break;
749 }
750 audit_log_common_recv_msg(&ab, msg_type, pid, uid,
751 loginuid, sessionid, sid);
752
753 if (msg_type != AUDIT_USER_TTY)
754 audit_log_format(ab, " msg='%.1024s'",
755 (char *)data);
756 else {
757 int size;
758
759 audit_log_format(ab, " msg=");
760 size = nlmsg_len(nlh);
761 if (size > 0 &&
762 ((unsigned char *)data)[size - 1] == '\0')
763 size--;
764 audit_log_n_untrustedstring(ab, data, size);
765 }
766 audit_set_pid(ab, pid);
767 audit_log_end(ab);
768 }
769 break;
770 case AUDIT_ADD:
771 case AUDIT_DEL:
772 if (nlmsg_len(nlh) < sizeof(struct audit_rule))
773 return -EINVAL;
774 if (audit_enabled == AUDIT_LOCKED) {
775 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
776 uid, loginuid, sessionid, sid);
777
778 audit_log_format(ab, " audit_enabled=%d res=0",
779 audit_enabled);
780 audit_log_end(ab);
781 return -EPERM;
782 }
783 /* fallthrough */
784 case AUDIT_LIST:
785 err = audit_receive_filter(msg_type, NETLINK_CB(skb).pid,
786 uid, seq, data, nlmsg_len(nlh),
787 loginuid, sessionid, sid);
788 break;
789 case AUDIT_ADD_RULE:
790 case AUDIT_DEL_RULE:
791 if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
792 return -EINVAL;
793 if (audit_enabled == AUDIT_LOCKED) {
794 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
795 uid, loginuid, sessionid, sid);
796
797 audit_log_format(ab, " audit_enabled=%d res=0",
798 audit_enabled);
799 audit_log_end(ab);
800 return -EPERM;
801 }
802 /* fallthrough */
803 case AUDIT_LIST_RULES:
804 err = audit_receive_filter(msg_type, NETLINK_CB(skb).pid,
805 uid, seq, data, nlmsg_len(nlh),
806 loginuid, sessionid, sid);
807 break;
808 case AUDIT_TRIM:
809 audit_trim_trees();
810
811 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
812 uid, loginuid, sessionid, sid);
813
814 audit_log_format(ab, " op=trim res=1");
815 audit_log_end(ab);
816 break;
817 case AUDIT_MAKE_EQUIV: {
818 void *bufp = data;
819 u32 sizes[2];
820 size_t msglen = nlmsg_len(nlh);
821 char *old, *new;
822
823 err = -EINVAL;
824 if (msglen < 2 * sizeof(u32))
825 break;
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]);
830 if (IS_ERR(old)) {
831 err = PTR_ERR(old);
832 break;
833 }
834 new = audit_unpack_string(&bufp, &msglen, sizes[1]);
835 if (IS_ERR(new)) {
836 err = PTR_ERR(new);
837 kfree(old);
838 break;
839 }
840 /* OK, here comes... */
841 err = audit_tag_tree(old, new);
842
843 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
844 uid, loginuid, sessionid, sid);
845
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);
851 audit_log_end(ab);
852 kfree(old);
853 kfree(new);
854 break;
855 }
856 case AUDIT_SIGNAL_INFO:
857 len = 0;
858 if (audit_sig_sid) {
859 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
860 if (err)
861 return err;
862 }
863 sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
864 if (!sig_data) {
865 if (audit_sig_sid)
866 security_release_secctx(ctx, len);
867 return -ENOMEM;
868 }
869 sig_data->uid = audit_sig_uid;
870 sig_data->pid = audit_sig_pid;
871 if (audit_sig_sid) {
872 memcpy(sig_data->ctx, ctx, len);
873 security_release_secctx(ctx, len);
874 }
875 audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_SIGNAL_INFO,
876 0, 0, sig_data, sizeof(*sig_data) + len);
877 kfree(sig_data);
878 break;
879 case AUDIT_TTY_GET: {
880 struct audit_tty_status s;
881 struct task_struct *tsk;
882 unsigned long flags;
883
884 rcu_read_lock();
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);
889 } else
890 err = -ESRCH;
891 rcu_read_unlock();
892
893 if (!err)
894 audit_send_reply(NETLINK_CB(skb).pid, seq,
895 AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
896 break;
897 }
898 case AUDIT_TTY_SET: {
899 struct audit_tty_status *s;
900 struct task_struct *tsk;
901 unsigned long flags;
902
903 if (nlh->nlmsg_len < sizeof(struct audit_tty_status))
904 return -EINVAL;
905 s = data;
906 if (s->enabled != 0 && s->enabled != 1)
907 return -EINVAL;
908 rcu_read_lock();
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);
913 } else
914 err = -ESRCH;
915 rcu_read_unlock();
916 break;
917 }
918 default:
919 err = -EINVAL;
920 break;
921 }
922
923 return err < 0 ? err : 0;
924}
925
926/*
927 * Get message from skb. Each message is processed by audit_receive_msg.
928 * Malformed skbs with wrong length are discarded silently.
929 */
930static void audit_receive_skb(struct sk_buff *skb)
931{
932 struct nlmsghdr *nlh;
933 /*
934 * len MUST be signed for NLMSG_NEXT to be able to dec it below 0
935 * if the nlmsg_len was not aligned
936 */
937 int len;
938 int err;
939
940 nlh = nlmsg_hdr(skb);
941 len = skb->len;
942
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);
948
949 nlh = NLMSG_NEXT(nlh, len);
950 }
951}
952
953/* Receive messages from netlink socket. */
954static void audit_receive(struct sk_buff *skb)
955{
956 mutex_lock(&audit_cmd_mutex);
957 audit_receive_skb(skb);
958 mutex_unlock(&audit_cmd_mutex);
959}
960
961/* Initialize audit support at boot time. */
962static int __init audit_init(void)
963{
964 int i;
965 struct netlink_kernel_cfg cfg = {
966 .input = audit_receive,
967 };
968
969 if (audit_initialized == AUDIT_DISABLED)
970 return 0;
971
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,
975 THIS_MODULE, &cfg);
976 if (!audit_sock)
977 audit_panic("cannot initialize netlink socket");
978 else
979 audit_sock->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
980
981 skb_queue_head_init(&audit_skb_queue);
982 skb_queue_head_init(&audit_skb_hold_queue);
983 audit_initialized = AUDIT_INITIALIZED;
984 audit_enabled = audit_default;
985 audit_ever_enabled |= !!audit_default;
986
987 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized");
988
989 for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
990 INIT_LIST_HEAD(&audit_inode_hash[i]);
991
992 return 0;
993}
994__initcall(audit_init);
995
996/* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
997static int __init audit_enable(char *str)
998{
999 audit_default = !!simple_strtol(str, NULL, 0);
1000 if (!audit_default)
1001 audit_initialized = AUDIT_DISABLED;
1002
1003 printk(KERN_INFO "audit: %s", audit_default ? "enabled" : "disabled");
1004
1005 if (audit_initialized == AUDIT_INITIALIZED) {
1006 audit_enabled = audit_default;
1007 audit_ever_enabled |= !!audit_default;
1008 } else if (audit_initialized == AUDIT_UNINITIALIZED) {
1009 printk(" (after initialization)");
1010 } else {
1011 printk(" (until reboot)");
1012 }
1013 printk("\n");
1014
1015 return 1;
1016}
1017
1018__setup("audit=", audit_enable);
1019
1020static void audit_buffer_free(struct audit_buffer *ab)
1021{
1022 unsigned long flags;
1023
1024 if (!ab)
1025 return;
1026
1027 if (ab->skb)
1028 kfree_skb(ab->skb);
1029
1030 spin_lock_irqsave(&audit_freelist_lock, flags);
1031 if (audit_freelist_count > AUDIT_MAXFREE)
1032 kfree(ab);
1033 else {
1034 audit_freelist_count++;
1035 list_add(&ab->list, &audit_freelist);
1036 }
1037 spin_unlock_irqrestore(&audit_freelist_lock, flags);
1038}
1039
1040static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx,
1041 gfp_t gfp_mask, int type)
1042{
1043 unsigned long flags;
1044 struct audit_buffer *ab = NULL;
1045 struct nlmsghdr *nlh;
1046
1047 spin_lock_irqsave(&audit_freelist_lock, flags);
1048 if (!list_empty(&audit_freelist)) {
1049 ab = list_entry(audit_freelist.next,
1050 struct audit_buffer, list);
1051 list_del(&ab->list);
1052 --audit_freelist_count;
1053 }
1054 spin_unlock_irqrestore(&audit_freelist_lock, flags);
1055
1056 if (!ab) {
1057 ab = kmalloc(sizeof(*ab), gfp_mask);
1058 if (!ab)
1059 goto err;
1060 }
1061
1062 ab->ctx = ctx;
1063 ab->gfp_mask = gfp_mask;
1064
1065 ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
1066 if (!ab->skb)
1067 goto err;
1068
1069 nlh = nlmsg_put(ab->skb, 0, 0, type, 0, 0);
1070 if (!nlh)
1071 goto out_kfree_skb;
1072
1073 return ab;
1074
1075out_kfree_skb:
1076 kfree_skb(ab->skb);
1077 ab->skb = NULL;
1078err:
1079 audit_buffer_free(ab);
1080 return NULL;
1081}
1082
1083/**
1084 * audit_serial - compute a serial number for the audit record
1085 *
1086 * Compute a serial number for the audit record. Audit records are
1087 * written to user-space as soon as they are generated, so a complete
1088 * audit record may be written in several pieces. The timestamp of the
1089 * record and this serial number are used by the user-space tools to
1090 * determine which pieces belong to the same audit record. The
1091 * (timestamp,serial) tuple is unique for each syscall and is live from
1092 * syscall entry to syscall exit.
1093 *
1094 * NOTE: Another possibility is to store the formatted records off the
1095 * audit context (for those records that have a context), and emit them
1096 * all at syscall exit. However, this could delay the reporting of
1097 * significant errors until syscall exit (or never, if the system
1098 * halts).
1099 */
1100unsigned int audit_serial(void)
1101{
1102 static DEFINE_SPINLOCK(serial_lock);
1103 static unsigned int serial = 0;
1104
1105 unsigned long flags;
1106 unsigned int ret;
1107
1108 spin_lock_irqsave(&serial_lock, flags);
1109 do {
1110 ret = ++serial;
1111 } while (unlikely(!ret));
1112 spin_unlock_irqrestore(&serial_lock, flags);
1113
1114 return ret;
1115}
1116
1117static inline void audit_get_stamp(struct audit_context *ctx,
1118 struct timespec *t, unsigned int *serial)
1119{
1120 if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
1121 *t = CURRENT_TIME;
1122 *serial = audit_serial();
1123 }
1124}
1125
1126/* Obtain an audit buffer. This routine does locking to obtain the
1127 * audit buffer, but then no locking is required for calls to
1128 * audit_log_*format. If the tsk is a task that is currently in a
1129 * syscall, then the syscall is marked as auditable and an audit record
1130 * will be written at syscall exit. If there is no associated task, tsk
1131 * should be NULL. */
1132
1133/**
1134 * audit_log_start - obtain an audit buffer
1135 * @ctx: audit_context (may be NULL)
1136 * @gfp_mask: type of allocation
1137 * @type: audit message type
1138 *
1139 * Returns audit_buffer pointer on success or NULL on error.
1140 *
1141 * Obtain an audit buffer. This routine does locking to obtain the
1142 * audit buffer, but then no locking is required for calls to
1143 * audit_log_*format. If the task (ctx) is a task that is currently in a
1144 * syscall, then the syscall is marked as auditable and an audit record
1145 * will be written at syscall exit. If there is no associated task, then
1146 * task context (ctx) should be NULL.
1147 */
1148struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1149 int type)
1150{
1151 struct audit_buffer *ab = NULL;
1152 struct timespec t;
1153 unsigned int uninitialized_var(serial);
1154 int reserve;
1155 unsigned long timeout_start = jiffies;
1156
1157 if (audit_initialized != AUDIT_INITIALIZED)
1158 return NULL;
1159
1160 if (unlikely(audit_filter_type(type)))
1161 return NULL;
1162
1163 if (gfp_mask & __GFP_WAIT)
1164 reserve = 0;
1165 else
1166 reserve = 5; /* Allow atomic callers to go up to five
1167 entries over the normal backlog limit */
1168
1169 while (audit_backlog_limit
1170 && skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) {
1171 if (gfp_mask & __GFP_WAIT && audit_backlog_wait_time
1172 && time_before(jiffies, timeout_start + audit_backlog_wait_time)) {
1173
1174 /* Wait for auditd to drain the queue a little */
1175 DECLARE_WAITQUEUE(wait, current);
1176 set_current_state(TASK_INTERRUPTIBLE);
1177 add_wait_queue(&audit_backlog_wait, &wait);
1178
1179 if (audit_backlog_limit &&
1180 skb_queue_len(&audit_skb_queue) > audit_backlog_limit)
1181 schedule_timeout(timeout_start + audit_backlog_wait_time - jiffies);
1182
1183 __set_current_state(TASK_RUNNING);
1184 remove_wait_queue(&audit_backlog_wait, &wait);
1185 continue;
1186 }
1187 if (audit_rate_check() && printk_ratelimit())
1188 printk(KERN_WARNING
1189 "audit: audit_backlog=%d > "
1190 "audit_backlog_limit=%d\n",
1191 skb_queue_len(&audit_skb_queue),
1192 audit_backlog_limit);
1193 audit_log_lost("backlog limit exceeded");
1194 audit_backlog_wait_time = audit_backlog_wait_overflow;
1195 wake_up(&audit_backlog_wait);
1196 return NULL;
1197 }
1198
1199 ab = audit_buffer_alloc(ctx, gfp_mask, type);
1200 if (!ab) {
1201 audit_log_lost("out of memory in audit_log_start");
1202 return NULL;
1203 }
1204
1205 audit_get_stamp(ab->ctx, &t, &serial);
1206
1207 audit_log_format(ab, "audit(%lu.%03lu:%u): ",
1208 t.tv_sec, t.tv_nsec/1000000, serial);
1209 return ab;
1210}
1211
1212/**
1213 * audit_expand - expand skb in the audit buffer
1214 * @ab: audit_buffer
1215 * @extra: space to add at tail of the skb
1216 *
1217 * Returns 0 (no space) on failed expansion, or available space if
1218 * successful.
1219 */
1220static inline int audit_expand(struct audit_buffer *ab, int extra)
1221{
1222 struct sk_buff *skb = ab->skb;
1223 int oldtail = skb_tailroom(skb);
1224 int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1225 int newtail = skb_tailroom(skb);
1226
1227 if (ret < 0) {
1228 audit_log_lost("out of memory in audit_expand");
1229 return 0;
1230 }
1231
1232 skb->truesize += newtail - oldtail;
1233 return newtail;
1234}
1235
1236/*
1237 * Format an audit message into the audit buffer. If there isn't enough
1238 * room in the audit buffer, more room will be allocated and vsnprint
1239 * will be called a second time. Currently, we assume that a printk
1240 * can't format message larger than 1024 bytes, so we don't either.
1241 */
1242static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1243 va_list args)
1244{
1245 int len, avail;
1246 struct sk_buff *skb;
1247 va_list args2;
1248
1249 if (!ab)
1250 return;
1251
1252 BUG_ON(!ab->skb);
1253 skb = ab->skb;
1254 avail = skb_tailroom(skb);
1255 if (avail == 0) {
1256 avail = audit_expand(ab, AUDIT_BUFSIZ);
1257 if (!avail)
1258 goto out;
1259 }
1260 va_copy(args2, args);
1261 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1262 if (len >= avail) {
1263 /* The printk buffer is 1024 bytes long, so if we get
1264 * here and AUDIT_BUFSIZ is at least 1024, then we can
1265 * log everything that printk could have logged. */
1266 avail = audit_expand(ab,
1267 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1268 if (!avail)
1269 goto out_va_end;
1270 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1271 }
1272 if (len > 0)
1273 skb_put(skb, len);
1274out_va_end:
1275 va_end(args2);
1276out:
1277 return;
1278}
1279
1280/**
1281 * audit_log_format - format a message into the audit buffer.
1282 * @ab: audit_buffer
1283 * @fmt: format string
1284 * @...: optional parameters matching @fmt string
1285 *
1286 * All the work is done in audit_log_vformat.
1287 */
1288void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1289{
1290 va_list args;
1291
1292 if (!ab)
1293 return;
1294 va_start(args, fmt);
1295 audit_log_vformat(ab, fmt, args);
1296 va_end(args);
1297}
1298
1299/**
1300 * audit_log_hex - convert a buffer to hex and append it to the audit skb
1301 * @ab: the audit_buffer
1302 * @buf: buffer to convert to hex
1303 * @len: length of @buf to be converted
1304 *
1305 * No return value; failure to expand is silently ignored.
1306 *
1307 * This function will take the passed buf and convert it into a string of
1308 * ascii hex digits. The new string is placed onto the skb.
1309 */
1310void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
1311 size_t len)
1312{
1313 int i, avail, new_len;
1314 unsigned char *ptr;
1315 struct sk_buff *skb;
1316 static const unsigned char *hex = "0123456789ABCDEF";
1317
1318 if (!ab)
1319 return;
1320
1321 BUG_ON(!ab->skb);
1322 skb = ab->skb;
1323 avail = skb_tailroom(skb);
1324 new_len = len<<1;
1325 if (new_len >= avail) {
1326 /* Round the buffer request up to the next multiple */
1327 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1328 avail = audit_expand(ab, new_len);
1329 if (!avail)
1330 return;
1331 }
1332
1333 ptr = skb_tail_pointer(skb);
1334 for (i=0; i<len; i++) {
1335 *ptr++ = hex[(buf[i] & 0xF0)>>4]; /* Upper nibble */
1336 *ptr++ = hex[buf[i] & 0x0F]; /* Lower nibble */
1337 }
1338 *ptr = 0;
1339 skb_put(skb, len << 1); /* new string is twice the old string */
1340}
1341
1342/*
1343 * Format a string of no more than slen characters into the audit buffer,
1344 * enclosed in quote marks.
1345 */
1346void audit_log_n_string(struct audit_buffer *ab, const char *string,
1347 size_t slen)
1348{
1349 int avail, new_len;
1350 unsigned char *ptr;
1351 struct sk_buff *skb;
1352
1353 if (!ab)
1354 return;
1355
1356 BUG_ON(!ab->skb);
1357 skb = ab->skb;
1358 avail = skb_tailroom(skb);
1359 new_len = slen + 3; /* enclosing quotes + null terminator */
1360 if (new_len > avail) {
1361 avail = audit_expand(ab, new_len);
1362 if (!avail)
1363 return;
1364 }
1365 ptr = skb_tail_pointer(skb);
1366 *ptr++ = '"';
1367 memcpy(ptr, string, slen);
1368 ptr += slen;
1369 *ptr++ = '"';
1370 *ptr = 0;
1371 skb_put(skb, slen + 2); /* don't include null terminator */
1372}
1373
1374/**
1375 * audit_string_contains_control - does a string need to be logged in hex
1376 * @string: string to be checked
1377 * @len: max length of the string to check
1378 */
1379int audit_string_contains_control(const char *string, size_t len)
1380{
1381 const unsigned char *p;
1382 for (p = string; p < (const unsigned char *)string + len; p++) {
1383 if (*p == '"' || *p < 0x21 || *p > 0x7e)
1384 return 1;
1385 }
1386 return 0;
1387}
1388
1389/**
1390 * audit_log_n_untrustedstring - log a string that may contain random characters
1391 * @ab: audit_buffer
1392 * @len: length of string (not including trailing null)
1393 * @string: string to be logged
1394 *
1395 * This code will escape a string that is passed to it if the string
1396 * contains a control character, unprintable character, double quote mark,
1397 * or a space. Unescaped strings will start and end with a double quote mark.
1398 * Strings that are escaped are printed in hex (2 digits per char).
1399 *
1400 * The caller specifies the number of characters in the string to log, which may
1401 * or may not be the entire string.
1402 */
1403void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
1404 size_t len)
1405{
1406 if (audit_string_contains_control(string, len))
1407 audit_log_n_hex(ab, string, len);
1408 else
1409 audit_log_n_string(ab, string, len);
1410}
1411
1412/**
1413 * audit_log_untrustedstring - log a string that may contain random characters
1414 * @ab: audit_buffer
1415 * @string: string to be logged
1416 *
1417 * Same as audit_log_n_untrustedstring(), except that strlen is used to
1418 * determine string length.
1419 */
1420void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
1421{
1422 audit_log_n_untrustedstring(ab, string, strlen(string));
1423}
1424
1425/* This is a helper-function to print the escaped d_path */
1426void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
1427 const struct path *path)
1428{
1429 char *p, *pathname;
1430
1431 if (prefix)
1432 audit_log_format(ab, "%s", prefix);
1433
1434 /* We will allow 11 spaces for ' (deleted)' to be appended */
1435 pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
1436 if (!pathname) {
1437 audit_log_string(ab, "<no_memory>");
1438 return;
1439 }
1440 p = d_path(path, pathname, PATH_MAX+11);
1441 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
1442 /* FIXME: can we save some information here? */
1443 audit_log_string(ab, "<too_long>");
1444 } else
1445 audit_log_untrustedstring(ab, p);
1446 kfree(pathname);
1447}
1448
1449void audit_log_key(struct audit_buffer *ab, char *key)
1450{
1451 audit_log_format(ab, " key=");
1452 if (key)
1453 audit_log_untrustedstring(ab, key);
1454 else
1455 audit_log_format(ab, "(null)");
1456}
1457
1458/**
1459 * audit_log_link_denied - report a link restriction denial
1460 * @operation: specific link opreation
1461 * @link: the path that triggered the restriction
1462 */
1463void audit_log_link_denied(const char *operation, struct path *link)
1464{
1465 struct audit_buffer *ab;
1466
1467 ab = audit_log_start(current->audit_context, GFP_KERNEL,
1468 AUDIT_ANOM_LINK);
1469 audit_log_format(ab, "op=%s action=denied", operation);
1470 audit_log_format(ab, " pid=%d comm=", current->pid);
1471 audit_log_untrustedstring(ab, current->comm);
1472 audit_log_d_path(ab, " path=", link);
1473 audit_log_format(ab, " dev=");
1474 audit_log_untrustedstring(ab, link->dentry->d_inode->i_sb->s_id);
1475 audit_log_format(ab, " ino=%lu", link->dentry->d_inode->i_ino);
1476 audit_log_end(ab);
1477}
1478
1479/**
1480 * audit_log_end - end one audit record
1481 * @ab: the audit_buffer
1482 *
1483 * The netlink_* functions cannot be called inside an irq context, so
1484 * the audit buffer is placed on a queue and a tasklet is scheduled to
1485 * remove them from the queue outside the irq context. May be called in
1486 * any context.
1487 */
1488void audit_log_end(struct audit_buffer *ab)
1489{
1490 if (!ab)
1491 return;
1492 if (!audit_rate_check()) {
1493 audit_log_lost("rate limit exceeded");
1494 } else {
1495 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
1496 nlh->nlmsg_len = ab->skb->len - NLMSG_SPACE(0);
1497
1498 if (audit_pid) {
1499 skb_queue_tail(&audit_skb_queue, ab->skb);
1500 wake_up_interruptible(&kauditd_wait);
1501 } else {
1502 audit_printk_skb(ab->skb);
1503 }
1504 ab->skb = NULL;
1505 }
1506 audit_buffer_free(ab);
1507}
1508
1509/**
1510 * audit_log - Log an audit record
1511 * @ctx: audit context
1512 * @gfp_mask: type of allocation
1513 * @type: audit message type
1514 * @fmt: format string to use
1515 * @...: variable parameters matching the format string
1516 *
1517 * This is a convenience function that calls audit_log_start,
1518 * audit_log_vformat, and audit_log_end. It may be called
1519 * in any context.
1520 */
1521void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
1522 const char *fmt, ...)
1523{
1524 struct audit_buffer *ab;
1525 va_list args;
1526
1527 ab = audit_log_start(ctx, gfp_mask, type);
1528 if (ab) {
1529 va_start(args, fmt);
1530 audit_log_vformat(ab, fmt, args);
1531 va_end(args);
1532 audit_log_end(ab);
1533 }
1534}
1535
1536#ifdef CONFIG_SECURITY
1537/**
1538 * audit_log_secctx - Converts and logs SELinux context
1539 * @ab: audit_buffer
1540 * @secid: security number
1541 *
1542 * This is a helper function that calls security_secid_to_secctx to convert
1543 * secid to secctx and then adds the (converted) SELinux context to the audit
1544 * log by calling audit_log_format, thus also preventing leak of internal secid
1545 * to userspace. If secid cannot be converted audit_panic is called.
1546 */
1547void audit_log_secctx(struct audit_buffer *ab, u32 secid)
1548{
1549 u32 len;
1550 char *secctx;
1551
1552 if (security_secid_to_secctx(secid, &secctx, &len)) {
1553 audit_panic("Cannot convert secid to context");
1554 } else {
1555 audit_log_format(ab, " obj=%s", secctx);
1556 security_release_secctx(secctx, len);
1557 }
1558}
1559EXPORT_SYMBOL(audit_log_secctx);
1560#endif
1561
1562EXPORT_SYMBOL(audit_log_start);
1563EXPORT_SYMBOL(audit_log_end);
1564EXPORT_SYMBOL(audit_log_format);
1565EXPORT_SYMBOL(audit_log);