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85c8721f 1/* audit.c -- Auditing support
1da177e4
LT
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 *
6a01b07f 5 * Copyright 2003-2007 Red Hat Inc., Durham, North Carolina.
1da177e4
LT
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 <faith@redhat.com>
23 *
d7a96f3a 24 * Goals: 1) Integrate fully with Security Modules.
1da177e4
LT
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 *
85c8721f 41 * Example user-space utilities: http://people.redhat.com/sgrubb/audit/
1da177e4
LT
42 */
43
44#include <linux/init.h>
1da177e4 45#include <asm/types.h>
715b49ef 46#include <asm/atomic.h>
1da177e4
LT
47#include <linux/mm.h>
48#include <linux/module.h>
5a0e3ad6 49#include <linux/slab.h>
b7d11258
DW
50#include <linux/err.h>
51#include <linux/kthread.h>
1da177e4
LT
52
53#include <linux/audit.h>
54
55#include <net/sock.h>
93315ed6 56#include <net/netlink.h>
1da177e4
LT
57#include <linux/skbuff.h>
58#include <linux/netlink.h>
7dfb7103 59#include <linux/freezer.h>
522ed776 60#include <linux/tty.h>
3dc7e315
DG
61
62#include "audit.h"
1da177e4 63
a3f07114 64/* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
1da177e4 65 * (Initialization happens after skb_init is called.) */
a3f07114
EP
66#define AUDIT_DISABLED -1
67#define AUDIT_UNINITIALIZED 0
68#define AUDIT_INITIALIZED 1
1da177e4
LT
69static int audit_initialized;
70
1a6b9f23
EP
71#define AUDIT_OFF 0
72#define AUDIT_ON 1
73#define AUDIT_LOCKED 2
1da177e4 74int audit_enabled;
b593d384 75int audit_ever_enabled;
1da177e4
LT
76
77/* Default state when kernel boots without any parameters. */
78static int audit_default;
79
80/* If auditing cannot proceed, audit_failure selects what happens. */
81static int audit_failure = AUDIT_FAIL_PRINTK;
82
75c0371a
PE
83/*
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.
87 */
c2f0c7c3 88int audit_pid;
75c0371a 89static int audit_nlk_pid;
1da177e4 90
b0dd25a8 91/* If audit_rate_limit is non-zero, limit the rate of sending audit records
1da177e4
LT
92 * to that number per second. This prevents DoS attacks, but results in
93 * audit records being dropped. */
94static int audit_rate_limit;
95
96/* Number of outstanding audit_buffers allowed. */
97static int audit_backlog_limit = 64;
ac4cec44
DW
98static int audit_backlog_wait_time = 60 * HZ;
99static int audit_backlog_wait_overflow = 0;
1da177e4 100
c2f0c7c3
SG
101/* The identity of the user shutting down the audit system. */
102uid_t audit_sig_uid = -1;
103pid_t audit_sig_pid = -1;
e1396065 104u32 audit_sig_sid = 0;
c2f0c7c3 105
1da177e4
LT
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
112*/
113static atomic_t audit_lost = ATOMIC_INIT(0);
114
115/* The netlink socket. */
116static struct sock *audit_sock;
117
f368c07d
AG
118/* Hash for inode-based rules */
119struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
120
b7d11258 121/* The audit_freelist is a list of pre-allocated audit buffers (if more
1da177e4
LT
122 * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
123 * being placed on the freelist). */
1da177e4 124static DEFINE_SPINLOCK(audit_freelist_lock);
b0dd25a8 125static int audit_freelist_count;
1da177e4
LT
126static LIST_HEAD(audit_freelist);
127
b7d11258 128static struct sk_buff_head audit_skb_queue;
f3d357b0
EP
129/* queue of skbs to send to auditd when/if it comes back */
130static struct sk_buff_head audit_skb_hold_queue;
b7d11258
DW
131static struct task_struct *kauditd_task;
132static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
9ad9ad38 133static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
1da177e4 134
f368c07d 135/* Serialize requests from userspace. */
916d7576 136DEFINE_MUTEX(audit_cmd_mutex);
1da177e4
LT
137
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
142
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)
146
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. */
152struct audit_buffer {
153 struct list_head list;
8fc6115c 154 struct sk_buff *skb; /* formatted skb ready to send */
1da177e4 155 struct audit_context *ctx; /* NULL or associated context */
9796fdd8 156 gfp_t gfp_mask;
1da177e4
LT
157};
158
f09ac9db
EP
159struct audit_reply {
160 int pid;
161 struct sk_buff *skb;
162};
163
c0404993
SG
164static void audit_set_pid(struct audit_buffer *ab, pid_t pid)
165{
50397bd1
EP
166 if (ab) {
167 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
168 nlh->nlmsg_pid = pid;
169 }
c0404993
SG
170}
171
8c8570fb 172void audit_panic(const char *message)
1da177e4
LT
173{
174 switch (audit_failure)
175 {
176 case AUDIT_FAIL_SILENT:
177 break;
178 case AUDIT_FAIL_PRINTK:
320f1b1e
EP
179 if (printk_ratelimit())
180 printk(KERN_ERR "audit: %s\n", message);
1da177e4
LT
181 break;
182 case AUDIT_FAIL_PANIC:
b29ee87e
EP
183 /* test audit_pid since printk is always losey, why bother? */
184 if (audit_pid)
185 panic("audit: %s\n", message);
1da177e4
LT
186 break;
187 }
188}
189
190static inline int audit_rate_check(void)
191{
192 static unsigned long last_check = 0;
193 static int messages = 0;
194 static DEFINE_SPINLOCK(lock);
195 unsigned long flags;
196 unsigned long now;
197 unsigned long elapsed;
198 int retval = 0;
199
200 if (!audit_rate_limit) return 1;
201
202 spin_lock_irqsave(&lock, flags);
203 if (++messages < audit_rate_limit) {
204 retval = 1;
205 } else {
206 now = jiffies;
207 elapsed = now - last_check;
208 if (elapsed > HZ) {
209 last_check = now;
210 messages = 0;
211 retval = 1;
212 }
213 }
214 spin_unlock_irqrestore(&lock, flags);
215
216 return retval;
217}
218
b0dd25a8
RD
219/**
220 * audit_log_lost - conditionally log lost audit message event
221 * @message: the message stating reason for lost audit message
222 *
223 * Emit at least 1 message per second, even if audit_rate_check is
224 * throttling.
225 * Always increment the lost messages counter.
226*/
1da177e4
LT
227void audit_log_lost(const char *message)
228{
229 static unsigned long last_msg = 0;
230 static DEFINE_SPINLOCK(lock);
231 unsigned long flags;
232 unsigned long now;
233 int print;
234
235 atomic_inc(&audit_lost);
236
237 print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
238
239 if (!print) {
240 spin_lock_irqsave(&lock, flags);
241 now = jiffies;
242 if (now - last_msg > HZ) {
243 print = 1;
244 last_msg = now;
245 }
246 spin_unlock_irqrestore(&lock, flags);
247 }
248
249 if (print) {
320f1b1e
EP
250 if (printk_ratelimit())
251 printk(KERN_WARNING
252 "audit: audit_lost=%d audit_rate_limit=%d "
253 "audit_backlog_limit=%d\n",
254 atomic_read(&audit_lost),
255 audit_rate_limit,
256 audit_backlog_limit);
1da177e4
LT
257 audit_panic(message);
258 }
1da177e4
LT
259}
260
1a6b9f23 261static int audit_log_config_change(char *function_name, int new, int old,
2532386f
EP
262 uid_t loginuid, u32 sessionid, u32 sid,
263 int allow_changes)
1da177e4 264{
1a6b9f23
EP
265 struct audit_buffer *ab;
266 int rc = 0;
ce29b682 267
1a6b9f23 268 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
2532386f
EP
269 audit_log_format(ab, "%s=%d old=%d auid=%u ses=%u", function_name, new,
270 old, loginuid, sessionid);
ce29b682
SG
271 if (sid) {
272 char *ctx = NULL;
273 u32 len;
1a6b9f23 274
2a862b32 275 rc = security_secid_to_secctx(sid, &ctx, &len);
1a6b9f23
EP
276 if (rc) {
277 audit_log_format(ab, " sid=%u", sid);
278 allow_changes = 0; /* Something weird, deny request */
279 } else {
280 audit_log_format(ab, " subj=%s", ctx);
2a862b32 281 security_release_secctx(ctx, len);
1a6b9f23 282 }
6a01b07f 283 }
1a6b9f23
EP
284 audit_log_format(ab, " res=%d", allow_changes);
285 audit_log_end(ab);
6a01b07f 286 return rc;
1da177e4
LT
287}
288
1a6b9f23 289static int audit_do_config_change(char *function_name, int *to_change,
2532386f
EP
290 int new, uid_t loginuid, u32 sessionid,
291 u32 sid)
1da177e4 292{
1a6b9f23 293 int allow_changes, rc = 0, old = *to_change;
6a01b07f
SG
294
295 /* check if we are locked */
1a6b9f23
EP
296 if (audit_enabled == AUDIT_LOCKED)
297 allow_changes = 0;
6a01b07f 298 else
1a6b9f23 299 allow_changes = 1;
ce29b682 300
1a6b9f23 301 if (audit_enabled != AUDIT_OFF) {
2532386f
EP
302 rc = audit_log_config_change(function_name, new, old, loginuid,
303 sessionid, sid, allow_changes);
1a6b9f23
EP
304 if (rc)
305 allow_changes = 0;
6a01b07f 306 }
6a01b07f
SG
307
308 /* If we are allowed, make the change */
1a6b9f23
EP
309 if (allow_changes == 1)
310 *to_change = new;
6a01b07f
SG
311 /* Not allowed, update reason */
312 else if (rc == 0)
313 rc = -EPERM;
314 return rc;
1da177e4
LT
315}
316
2532386f
EP
317static int audit_set_rate_limit(int limit, uid_t loginuid, u32 sessionid,
318 u32 sid)
1da177e4 319{
1a6b9f23 320 return audit_do_config_change("audit_rate_limit", &audit_rate_limit,
2532386f 321 limit, loginuid, sessionid, sid);
1a6b9f23 322}
ce29b682 323
2532386f
EP
324static int audit_set_backlog_limit(int limit, uid_t loginuid, u32 sessionid,
325 u32 sid)
1a6b9f23
EP
326{
327 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit,
2532386f 328 limit, loginuid, sessionid, sid);
1a6b9f23 329}
6a01b07f 330
2532386f 331static int audit_set_enabled(int state, uid_t loginuid, u32 sessionid, u32 sid)
1a6b9f23 332{
b593d384 333 int rc;
1a6b9f23
EP
334 if (state < AUDIT_OFF || state > AUDIT_LOCKED)
335 return -EINVAL;
6a01b07f 336
b593d384 337 rc = audit_do_config_change("audit_enabled", &audit_enabled, state,
2532386f 338 loginuid, sessionid, sid);
b593d384
EP
339
340 if (!rc)
341 audit_ever_enabled |= !!state;
342
343 return rc;
1da177e4
LT
344}
345
2532386f 346static int audit_set_failure(int state, uid_t loginuid, u32 sessionid, u32 sid)
1da177e4 347{
1da177e4
LT
348 if (state != AUDIT_FAIL_SILENT
349 && state != AUDIT_FAIL_PRINTK
350 && state != AUDIT_FAIL_PANIC)
351 return -EINVAL;
ce29b682 352
1a6b9f23 353 return audit_do_config_change("audit_failure", &audit_failure, state,
2532386f 354 loginuid, sessionid, sid);
1da177e4
LT
355}
356
f3d357b0
EP
357/*
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.
365 */
366static void audit_hold_skb(struct sk_buff *skb)
367{
368 if (audit_default &&
369 skb_queue_len(&audit_skb_hold_queue) < audit_backlog_limit)
370 skb_queue_tail(&audit_skb_hold_queue, skb);
371 else
372 kfree_skb(skb);
373}
374
038cbcf6
EP
375/*
376 * For one reason or another this nlh isn't getting delivered to the userspace
377 * audit daemon, just send it to printk.
378 */
379static void audit_printk_skb(struct sk_buff *skb)
380{
381 struct nlmsghdr *nlh = nlmsg_hdr(skb);
382 char *data = NLMSG_DATA(nlh);
383
384 if (nlh->nlmsg_type != AUDIT_EOE) {
385 if (printk_ratelimit())
386 printk(KERN_NOTICE "type=%d %s\n", nlh->nlmsg_type, data);
387 else
388 audit_log_lost("printk limit exceeded\n");
389 }
390
391 audit_hold_skb(skb);
392}
393
f3d357b0
EP
394static void kauditd_send_skb(struct sk_buff *skb)
395{
396 int err;
397 /* take a reference in case we can't send it and we want to hold it */
398 skb_get(skb);
399 err = netlink_unicast(audit_sock, skb, audit_nlk_pid, 0);
400 if (err < 0) {
c9404c9c 401 BUG_ON(err != -ECONNREFUSED); /* Shouldn't happen */
f3d357b0
EP
402 printk(KERN_ERR "audit: *NO* daemon at audit_pid=%d\n", audit_pid);
403 audit_log_lost("auditd dissapeared\n");
404 audit_pid = 0;
405 /* we might get lucky and get this in the next auditd */
406 audit_hold_skb(skb);
407 } else
408 /* drop the extra reference if sent ok */
70d4bf6d 409 consume_skb(skb);
f3d357b0
EP
410}
411
97a41e26 412static int kauditd_thread(void *dummy)
b7d11258
DW
413{
414 struct sk_buff *skb;
415
83144186 416 set_freezable();
4899b8b1 417 while (!kthread_should_stop()) {
f3d357b0
EP
418 /*
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
423 * doesn't matter.
424 *
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.
430 */
431 if (audit_default && audit_pid) {
432 skb = skb_dequeue(&audit_skb_hold_queue);
433 if (unlikely(skb)) {
434 while (skb && audit_pid) {
435 kauditd_send_skb(skb);
436 skb = skb_dequeue(&audit_skb_hold_queue);
437 }
438 }
439 }
440
b7d11258 441 skb = skb_dequeue(&audit_skb_queue);
9ad9ad38 442 wake_up(&audit_backlog_wait);
b7d11258 443 if (skb) {
f3d357b0
EP
444 if (audit_pid)
445 kauditd_send_skb(skb);
038cbcf6
EP
446 else
447 audit_printk_skb(skb);
b7d11258
DW
448 } else {
449 DECLARE_WAITQUEUE(wait, current);
450 set_current_state(TASK_INTERRUPTIBLE);
451 add_wait_queue(&kauditd_wait, &wait);
452
7a4ae749
PO
453 if (!skb_queue_len(&audit_skb_queue)) {
454 try_to_freeze();
b7d11258 455 schedule();
7a4ae749 456 }
b7d11258
DW
457
458 __set_current_state(TASK_RUNNING);
459 remove_wait_queue(&kauditd_wait, &wait);
460 }
461 }
4899b8b1 462 return 0;
b7d11258
DW
463}
464
2532386f 465static int audit_prepare_user_tty(pid_t pid, uid_t loginuid, u32 sessionid)
522ed776
MT
466{
467 struct task_struct *tsk;
468 int err;
469
470 read_lock(&tasklist_lock);
4a761b8c 471 tsk = find_task_by_vpid(pid);
522ed776
MT
472 err = -ESRCH;
473 if (!tsk)
474 goto out;
475 err = 0;
476
477 spin_lock_irq(&tsk->sighand->siglock);
478 if (!tsk->signal->audit_tty)
479 err = -EPERM;
480 spin_unlock_irq(&tsk->sighand->siglock);
481 if (err)
482 goto out;
483
2532386f 484 tty_audit_push_task(tsk, loginuid, sessionid);
522ed776
MT
485out:
486 read_unlock(&tasklist_lock);
487 return err;
488}
489
9044e6bc
AV
490int audit_send_list(void *_dest)
491{
492 struct audit_netlink_list *dest = _dest;
493 int pid = dest->pid;
494 struct sk_buff *skb;
495
496 /* wait for parent to finish and send an ACK */
f368c07d
AG
497 mutex_lock(&audit_cmd_mutex);
498 mutex_unlock(&audit_cmd_mutex);
9044e6bc
AV
499
500 while ((skb = __skb_dequeue(&dest->q)) != NULL)
501 netlink_unicast(audit_sock, skb, pid, 0);
502
503 kfree(dest);
504
505 return 0;
506}
507
508struct sk_buff *audit_make_reply(int pid, int seq, int type, int done,
509 int multi, void *payload, int size)
510{
511 struct sk_buff *skb;
512 struct nlmsghdr *nlh;
9044e6bc
AV
513 void *data;
514 int flags = multi ? NLM_F_MULTI : 0;
515 int t = done ? NLMSG_DONE : type;
516
ee080e6c 517 skb = nlmsg_new(size, GFP_KERNEL);
9044e6bc
AV
518 if (!skb)
519 return NULL;
520
ee080e6c
EP
521 nlh = NLMSG_NEW(skb, pid, seq, t, size, flags);
522 data = NLMSG_DATA(nlh);
9044e6bc
AV
523 memcpy(data, payload, size);
524 return skb;
525
ee080e6c 526nlmsg_failure: /* Used by NLMSG_NEW */
9044e6bc
AV
527 if (skb)
528 kfree_skb(skb);
529 return NULL;
530}
531
f09ac9db
EP
532static int audit_send_reply_thread(void *arg)
533{
534 struct audit_reply *reply = (struct audit_reply *)arg;
535
536 mutex_lock(&audit_cmd_mutex);
537 mutex_unlock(&audit_cmd_mutex);
538
539 /* Ignore failure. It'll only happen if the sender goes away,
540 because our timeout is set to infinite. */
541 netlink_unicast(audit_sock, reply->skb, reply->pid, 0);
542 kfree(reply);
543 return 0;
544}
b0dd25a8
RD
545/**
546 * audit_send_reply - send an audit reply message via netlink
547 * @pid: process id to send reply to
548 * @seq: sequence number
549 * @type: audit message type
550 * @done: done (last) flag
551 * @multi: multi-part message flag
552 * @payload: payload data
553 * @size: payload size
554 *
555 * Allocates an skb, builds the netlink message, and sends it to the pid.
556 * No failure notifications.
557 */
1da177e4
LT
558void audit_send_reply(int pid, int seq, int type, int done, int multi,
559 void *payload, int size)
560{
f09ac9db
EP
561 struct sk_buff *skb;
562 struct task_struct *tsk;
563 struct audit_reply *reply = kmalloc(sizeof(struct audit_reply),
564 GFP_KERNEL);
565
566 if (!reply)
567 return;
568
9044e6bc 569 skb = audit_make_reply(pid, seq, type, done, multi, payload, size);
1da177e4 570 if (!skb)
fcaf1eb8 571 goto out;
f09ac9db
EP
572
573 reply->pid = pid;
574 reply->skb = skb;
575
576 tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
fcaf1eb8
AM
577 if (!IS_ERR(tsk))
578 return;
579 kfree_skb(skb);
580out:
581 kfree(reply);
1da177e4
LT
582}
583
584/*
585 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
586 * control messages.
587 */
c7bdb545 588static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
1da177e4
LT
589{
590 int err = 0;
591
592 switch (msg_type) {
593 case AUDIT_GET:
594 case AUDIT_LIST:
93315ed6 595 case AUDIT_LIST_RULES:
1da177e4
LT
596 case AUDIT_SET:
597 case AUDIT_ADD:
93315ed6 598 case AUDIT_ADD_RULE:
1da177e4 599 case AUDIT_DEL:
93315ed6 600 case AUDIT_DEL_RULE:
c2f0c7c3 601 case AUDIT_SIGNAL_INFO:
522ed776
MT
602 case AUDIT_TTY_GET:
603 case AUDIT_TTY_SET:
74c3cbe3
AV
604 case AUDIT_TRIM:
605 case AUDIT_MAKE_EQUIV:
c7bdb545 606 if (security_netlink_recv(skb, CAP_AUDIT_CONTROL))
1da177e4
LT
607 err = -EPERM;
608 break;
05474106 609 case AUDIT_USER:
039b6b3e
RD
610 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
611 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
c7bdb545 612 if (security_netlink_recv(skb, CAP_AUDIT_WRITE))
1da177e4
LT
613 err = -EPERM;
614 break;
615 default: /* bad msg */
616 err = -EINVAL;
617 }
618
619 return err;
620}
621
50397bd1 622static int audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type,
2532386f
EP
623 u32 pid, u32 uid, uid_t auid, u32 ses,
624 u32 sid)
50397bd1
EP
625{
626 int rc = 0;
627 char *ctx = NULL;
628 u32 len;
629
630 if (!audit_enabled) {
631 *ab = NULL;
632 return rc;
633 }
634
635 *ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
2532386f
EP
636 audit_log_format(*ab, "user pid=%d uid=%u auid=%u ses=%u",
637 pid, uid, auid, ses);
50397bd1 638 if (sid) {
2a862b32 639 rc = security_secid_to_secctx(sid, &ctx, &len);
50397bd1
EP
640 if (rc)
641 audit_log_format(*ab, " ssid=%u", sid);
2a862b32 642 else {
50397bd1 643 audit_log_format(*ab, " subj=%s", ctx);
2a862b32
AD
644 security_release_secctx(ctx, len);
645 }
50397bd1
EP
646 }
647
648 return rc;
649}
650
1da177e4
LT
651static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
652{
e7c34970 653 u32 uid, pid, seq, sid;
1da177e4
LT
654 void *data;
655 struct audit_status *status_get, status_set;
656 int err;
c0404993 657 struct audit_buffer *ab;
1da177e4 658 u16 msg_type = nlh->nlmsg_type;
c94c257c 659 uid_t loginuid; /* loginuid of sender */
2532386f 660 u32 sessionid;
e1396065 661 struct audit_sig_info *sig_data;
50397bd1 662 char *ctx = NULL;
e1396065 663 u32 len;
1da177e4 664
c7bdb545 665 err = audit_netlink_ok(skb, msg_type);
1da177e4
LT
666 if (err)
667 return err;
668
b0dd25a8
RD
669 /* As soon as there's any sign of userspace auditd,
670 * start kauditd to talk to it */
b7d11258
DW
671 if (!kauditd_task)
672 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
673 if (IS_ERR(kauditd_task)) {
674 err = PTR_ERR(kauditd_task);
675 kauditd_task = NULL;
676 return err;
677 }
678
1da177e4
LT
679 pid = NETLINK_CREDS(skb)->pid;
680 uid = NETLINK_CREDS(skb)->uid;
c94c257c 681 loginuid = NETLINK_CB(skb).loginuid;
2532386f 682 sessionid = NETLINK_CB(skb).sessionid;
e7c34970 683 sid = NETLINK_CB(skb).sid;
1da177e4
LT
684 seq = nlh->nlmsg_seq;
685 data = NLMSG_DATA(nlh);
686
687 switch (msg_type) {
688 case AUDIT_GET:
689 status_set.enabled = audit_enabled;
690 status_set.failure = audit_failure;
691 status_set.pid = audit_pid;
692 status_set.rate_limit = audit_rate_limit;
693 status_set.backlog_limit = audit_backlog_limit;
694 status_set.lost = atomic_read(&audit_lost);
b7d11258 695 status_set.backlog = skb_queue_len(&audit_skb_queue);
1da177e4
LT
696 audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_GET, 0, 0,
697 &status_set, sizeof(status_set));
698 break;
699 case AUDIT_SET:
700 if (nlh->nlmsg_len < sizeof(struct audit_status))
701 return -EINVAL;
702 status_get = (struct audit_status *)data;
703 if (status_get->mask & AUDIT_STATUS_ENABLED) {
ce29b682 704 err = audit_set_enabled(status_get->enabled,
2532386f 705 loginuid, sessionid, sid);
20c6aaa3 706 if (err < 0)
707 return err;
1da177e4
LT
708 }
709 if (status_get->mask & AUDIT_STATUS_FAILURE) {
ce29b682 710 err = audit_set_failure(status_get->failure,
2532386f 711 loginuid, sessionid, sid);
20c6aaa3 712 if (err < 0)
713 return err;
1da177e4
LT
714 }
715 if (status_get->mask & AUDIT_STATUS_PID) {
1a6b9f23
EP
716 int new_pid = status_get->pid;
717
718 if (audit_enabled != AUDIT_OFF)
719 audit_log_config_change("audit_pid", new_pid,
720 audit_pid, loginuid,
2532386f 721 sessionid, sid, 1);
1a6b9f23
EP
722
723 audit_pid = new_pid;
75c0371a 724 audit_nlk_pid = NETLINK_CB(skb).pid;
1da177e4 725 }
20c6aaa3 726 if (status_get->mask & AUDIT_STATUS_RATE_LIMIT) {
5d136a01 727 err = audit_set_rate_limit(status_get->rate_limit,
2532386f 728 loginuid, sessionid, sid);
20c6aaa3 729 if (err < 0)
730 return err;
731 }
1da177e4 732 if (status_get->mask & AUDIT_STATUS_BACKLOG_LIMIT)
5d136a01 733 err = audit_set_backlog_limit(status_get->backlog_limit,
2532386f 734 loginuid, sessionid, sid);
1da177e4 735 break;
05474106 736 case AUDIT_USER:
039b6b3e
RD
737 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
738 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
4a4cd633
DW
739 if (!audit_enabled && msg_type != AUDIT_USER_AVC)
740 return 0;
741
d8de7247 742 err = audit_filter_user(&NETLINK_CB(skb));
4a4cd633
DW
743 if (err == 1) {
744 err = 0;
522ed776 745 if (msg_type == AUDIT_USER_TTY) {
2532386f
EP
746 err = audit_prepare_user_tty(pid, loginuid,
747 sessionid);
522ed776
MT
748 if (err)
749 break;
750 }
50397bd1 751 audit_log_common_recv_msg(&ab, msg_type, pid, uid,
2532386f 752 loginuid, sessionid, sid);
50397bd1
EP
753
754 if (msg_type != AUDIT_USER_TTY)
755 audit_log_format(ab, " msg='%.1024s'",
756 (char *)data);
757 else {
758 int size;
759
760 audit_log_format(ab, " msg=");
761 size = nlmsg_len(nlh);
55ad2f8d
MT
762 if (size > 0 &&
763 ((unsigned char *)data)[size - 1] == '\0')
764 size--;
b556f8ad 765 audit_log_n_untrustedstring(ab, data, size);
4a4cd633 766 }
50397bd1
EP
767 audit_set_pid(ab, pid);
768 audit_log_end(ab);
0f45aa18 769 }
1da177e4
LT
770 break;
771 case AUDIT_ADD:
772 case AUDIT_DEL:
93315ed6 773 if (nlmsg_len(nlh) < sizeof(struct audit_rule))
1da177e4 774 return -EINVAL;
1a6b9f23 775 if (audit_enabled == AUDIT_LOCKED) {
50397bd1 776 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
2532386f 777 uid, loginuid, sessionid, sid);
50397bd1
EP
778
779 audit_log_format(ab, " audit_enabled=%d res=0",
780 audit_enabled);
781 audit_log_end(ab);
6a01b07f
SG
782 return -EPERM;
783 }
1da177e4
LT
784 /* fallthrough */
785 case AUDIT_LIST:
13d5ef97 786 err = audit_receive_filter(msg_type, NETLINK_CB(skb).pid,
93315ed6 787 uid, seq, data, nlmsg_len(nlh),
2532386f 788 loginuid, sessionid, sid);
93315ed6
AG
789 break;
790 case AUDIT_ADD_RULE:
791 case AUDIT_DEL_RULE:
792 if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
793 return -EINVAL;
1a6b9f23 794 if (audit_enabled == AUDIT_LOCKED) {
50397bd1 795 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
2532386f 796 uid, loginuid, sessionid, sid);
50397bd1
EP
797
798 audit_log_format(ab, " audit_enabled=%d res=0",
799 audit_enabled);
800 audit_log_end(ab);
6a01b07f
SG
801 return -EPERM;
802 }
93315ed6
AG
803 /* fallthrough */
804 case AUDIT_LIST_RULES:
13d5ef97 805 err = audit_receive_filter(msg_type, NETLINK_CB(skb).pid,
93315ed6 806 uid, seq, data, nlmsg_len(nlh),
2532386f 807 loginuid, sessionid, sid);
1da177e4 808 break;
74c3cbe3
AV
809 case AUDIT_TRIM:
810 audit_trim_trees();
50397bd1
EP
811
812 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
2532386f 813 uid, loginuid, sessionid, sid);
50397bd1 814
74c3cbe3
AV
815 audit_log_format(ab, " op=trim res=1");
816 audit_log_end(ab);
817 break;
818 case AUDIT_MAKE_EQUIV: {
819 void *bufp = data;
820 u32 sizes[2];
7719e437 821 size_t msglen = nlmsg_len(nlh);
74c3cbe3
AV
822 char *old, *new;
823
824 err = -EINVAL;
7719e437 825 if (msglen < 2 * sizeof(u32))
74c3cbe3
AV
826 break;
827 memcpy(sizes, bufp, 2 * sizeof(u32));
828 bufp += 2 * sizeof(u32);
7719e437
HH
829 msglen -= 2 * sizeof(u32);
830 old = audit_unpack_string(&bufp, &msglen, sizes[0]);
74c3cbe3
AV
831 if (IS_ERR(old)) {
832 err = PTR_ERR(old);
833 break;
834 }
7719e437 835 new = audit_unpack_string(&bufp, &msglen, sizes[1]);
74c3cbe3
AV
836 if (IS_ERR(new)) {
837 err = PTR_ERR(new);
838 kfree(old);
839 break;
840 }
841 /* OK, here comes... */
842 err = audit_tag_tree(old, new);
843
50397bd1 844 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
2532386f 845 uid, loginuid, sessionid, sid);
50397bd1 846
74c3cbe3
AV
847 audit_log_format(ab, " op=make_equiv old=");
848 audit_log_untrustedstring(ab, old);
849 audit_log_format(ab, " new=");
850 audit_log_untrustedstring(ab, new);
851 audit_log_format(ab, " res=%d", !err);
852 audit_log_end(ab);
853 kfree(old);
854 kfree(new);
855 break;
856 }
c2f0c7c3 857 case AUDIT_SIGNAL_INFO:
939cbf26
EP
858 len = 0;
859 if (audit_sig_sid) {
860 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
861 if (err)
862 return err;
863 }
e1396065
AV
864 sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
865 if (!sig_data) {
939cbf26
EP
866 if (audit_sig_sid)
867 security_release_secctx(ctx, len);
e1396065
AV
868 return -ENOMEM;
869 }
870 sig_data->uid = audit_sig_uid;
871 sig_data->pid = audit_sig_pid;
939cbf26
EP
872 if (audit_sig_sid) {
873 memcpy(sig_data->ctx, ctx, len);
874 security_release_secctx(ctx, len);
875 }
5600b892 876 audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_SIGNAL_INFO,
e1396065
AV
877 0, 0, sig_data, sizeof(*sig_data) + len);
878 kfree(sig_data);
c2f0c7c3 879 break;
522ed776
MT
880 case AUDIT_TTY_GET: {
881 struct audit_tty_status s;
882 struct task_struct *tsk;
883
884 read_lock(&tasklist_lock);
4a761b8c 885 tsk = find_task_by_vpid(pid);
522ed776
MT
886 if (!tsk)
887 err = -ESRCH;
888 else {
889 spin_lock_irq(&tsk->sighand->siglock);
890 s.enabled = tsk->signal->audit_tty != 0;
891 spin_unlock_irq(&tsk->sighand->siglock);
892 }
893 read_unlock(&tasklist_lock);
894 audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_TTY_GET, 0, 0,
895 &s, sizeof(s));
896 break;
897 }
898 case AUDIT_TTY_SET: {
899 struct audit_tty_status *s;
900 struct task_struct *tsk;
901
902 if (nlh->nlmsg_len < sizeof(struct audit_tty_status))
903 return -EINVAL;
904 s = data;
905 if (s->enabled != 0 && s->enabled != 1)
906 return -EINVAL;
907 read_lock(&tasklist_lock);
4a761b8c 908 tsk = find_task_by_vpid(pid);
522ed776
MT
909 if (!tsk)
910 err = -ESRCH;
911 else {
912 spin_lock_irq(&tsk->sighand->siglock);
913 tsk->signal->audit_tty = s->enabled != 0;
914 spin_unlock_irq(&tsk->sighand->siglock);
915 }
916 read_unlock(&tasklist_lock);
917 break;
918 }
1da177e4
LT
919 default:
920 err = -EINVAL;
921 break;
922 }
923
924 return err < 0 ? err : 0;
925}
926
b0dd25a8 927/*
ea7ae60b
EP
928 * Get message from skb. Each message is processed by audit_receive_msg.
929 * Malformed skbs with wrong length are discarded silently.
b0dd25a8 930 */
2a0a6ebe 931static void audit_receive_skb(struct sk_buff *skb)
1da177e4 932{
ea7ae60b
EP
933 struct nlmsghdr *nlh;
934 /*
935 * len MUST be signed for NLMSG_NEXT to be able to dec it below 0
936 * if the nlmsg_len was not aligned
937 */
938 int len;
939 int err;
940
941 nlh = nlmsg_hdr(skb);
942 len = skb->len;
943
944 while (NLMSG_OK(nlh, len)) {
945 err = audit_receive_msg(skb, nlh);
946 /* if err or if this message says it wants a response */
947 if (err || (nlh->nlmsg_flags & NLM_F_ACK))
1da177e4 948 netlink_ack(skb, nlh, err);
ea7ae60b
EP
949
950 nlh = NLMSG_NEXT(nlh, len);
1da177e4 951 }
1da177e4
LT
952}
953
954/* Receive messages from netlink socket. */
cd40b7d3 955static void audit_receive(struct sk_buff *skb)
1da177e4 956{
f368c07d 957 mutex_lock(&audit_cmd_mutex);
cd40b7d3 958 audit_receive_skb(skb);
f368c07d 959 mutex_unlock(&audit_cmd_mutex);
1da177e4
LT
960}
961
1da177e4
LT
962/* Initialize audit support at boot time. */
963static int __init audit_init(void)
964{
f368c07d 965 int i;
f368c07d 966
a3f07114
EP
967 if (audit_initialized == AUDIT_DISABLED)
968 return 0;
969
1da177e4
LT
970 printk(KERN_INFO "audit: initializing netlink socket (%s)\n",
971 audit_default ? "enabled" : "disabled");
b4b51029
EB
972 audit_sock = netlink_kernel_create(&init_net, NETLINK_AUDIT, 0,
973 audit_receive, NULL, THIS_MODULE);
1da177e4
LT
974 if (!audit_sock)
975 audit_panic("cannot initialize netlink socket");
71e1c784
AG
976 else
977 audit_sock->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
1da177e4 978
b7d11258 979 skb_queue_head_init(&audit_skb_queue);
f3d357b0 980 skb_queue_head_init(&audit_skb_hold_queue);
a3f07114 981 audit_initialized = AUDIT_INITIALIZED;
1da177e4 982 audit_enabled = audit_default;
b593d384 983 audit_ever_enabled |= !!audit_default;
3dc7e315 984
9ad9ad38 985 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized");
f368c07d 986
f368c07d
AG
987 for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
988 INIT_LIST_HEAD(&audit_inode_hash[i]);
f368c07d 989
1da177e4
LT
990 return 0;
991}
1da177e4
LT
992__initcall(audit_init);
993
994/* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
995static int __init audit_enable(char *str)
996{
997 audit_default = !!simple_strtol(str, NULL, 0);
a3f07114
EP
998 if (!audit_default)
999 audit_initialized = AUDIT_DISABLED;
1000
1001 printk(KERN_INFO "audit: %s", audit_default ? "enabled" : "disabled");
1002
1003 if (audit_initialized == AUDIT_INITIALIZED) {
1da177e4 1004 audit_enabled = audit_default;
b593d384 1005 audit_ever_enabled |= !!audit_default;
a3f07114
EP
1006 } else if (audit_initialized == AUDIT_UNINITIALIZED) {
1007 printk(" (after initialization)");
1008 } else {
1009 printk(" (until reboot)");
b593d384 1010 }
a3f07114
EP
1011 printk("\n");
1012
9b41046c 1013 return 1;
1da177e4
LT
1014}
1015
1016__setup("audit=", audit_enable);
1017
16e1904e
CW
1018static void audit_buffer_free(struct audit_buffer *ab)
1019{
1020 unsigned long flags;
1021
8fc6115c
CW
1022 if (!ab)
1023 return;
1024
5ac52f33
CW
1025 if (ab->skb)
1026 kfree_skb(ab->skb);
b7d11258 1027
16e1904e 1028 spin_lock_irqsave(&audit_freelist_lock, flags);
5d136a01 1029 if (audit_freelist_count > AUDIT_MAXFREE)
16e1904e 1030 kfree(ab);
5d136a01
SH
1031 else {
1032 audit_freelist_count++;
16e1904e 1033 list_add(&ab->list, &audit_freelist);
5d136a01 1034 }
16e1904e
CW
1035 spin_unlock_irqrestore(&audit_freelist_lock, flags);
1036}
1037
c0404993 1038static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx,
dd0fc66f 1039 gfp_t gfp_mask, int type)
16e1904e
CW
1040{
1041 unsigned long flags;
1042 struct audit_buffer *ab = NULL;
c0404993 1043 struct nlmsghdr *nlh;
16e1904e
CW
1044
1045 spin_lock_irqsave(&audit_freelist_lock, flags);
1046 if (!list_empty(&audit_freelist)) {
1047 ab = list_entry(audit_freelist.next,
1048 struct audit_buffer, list);
1049 list_del(&ab->list);
1050 --audit_freelist_count;
1051 }
1052 spin_unlock_irqrestore(&audit_freelist_lock, flags);
1053
1054 if (!ab) {
4332bdd3 1055 ab = kmalloc(sizeof(*ab), gfp_mask);
16e1904e 1056 if (!ab)
8fc6115c 1057 goto err;
16e1904e 1058 }
8fc6115c 1059
b7d11258 1060 ab->ctx = ctx;
9ad9ad38 1061 ab->gfp_mask = gfp_mask;
ee080e6c
EP
1062
1063 ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
1064 if (!ab->skb)
1065 goto nlmsg_failure;
1066
1067 nlh = NLMSG_NEW(ab->skb, 0, 0, type, 0, 0);
1068
16e1904e 1069 return ab;
ee080e6c
EP
1070
1071nlmsg_failure: /* Used by NLMSG_NEW */
1072 kfree_skb(ab->skb);
1073 ab->skb = NULL;
8fc6115c
CW
1074err:
1075 audit_buffer_free(ab);
1076 return NULL;
16e1904e 1077}
1da177e4 1078
b0dd25a8
RD
1079/**
1080 * audit_serial - compute a serial number for the audit record
1081 *
1082 * Compute a serial number for the audit record. Audit records are
bfb4496e
DW
1083 * written to user-space as soon as they are generated, so a complete
1084 * audit record may be written in several pieces. The timestamp of the
1085 * record and this serial number are used by the user-space tools to
1086 * determine which pieces belong to the same audit record. The
1087 * (timestamp,serial) tuple is unique for each syscall and is live from
1088 * syscall entry to syscall exit.
1089 *
bfb4496e
DW
1090 * NOTE: Another possibility is to store the formatted records off the
1091 * audit context (for those records that have a context), and emit them
1092 * all at syscall exit. However, this could delay the reporting of
1093 * significant errors until syscall exit (or never, if the system
b0dd25a8
RD
1094 * halts).
1095 */
bfb4496e
DW
1096unsigned int audit_serial(void)
1097{
34af946a 1098 static DEFINE_SPINLOCK(serial_lock);
d5b454f2
DW
1099 static unsigned int serial = 0;
1100
1101 unsigned long flags;
1102 unsigned int ret;
bfb4496e 1103
d5b454f2 1104 spin_lock_irqsave(&serial_lock, flags);
bfb4496e 1105 do {
ce625a80
DW
1106 ret = ++serial;
1107 } while (unlikely(!ret));
d5b454f2 1108 spin_unlock_irqrestore(&serial_lock, flags);
bfb4496e 1109
d5b454f2 1110 return ret;
bfb4496e
DW
1111}
1112
5600b892 1113static inline void audit_get_stamp(struct audit_context *ctx,
bfb4496e
DW
1114 struct timespec *t, unsigned int *serial)
1115{
48887e63 1116 if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
bfb4496e
DW
1117 *t = CURRENT_TIME;
1118 *serial = audit_serial();
1119 }
1120}
1121
1da177e4
LT
1122/* Obtain an audit buffer. This routine does locking to obtain the
1123 * audit buffer, but then no locking is required for calls to
1124 * audit_log_*format. If the tsk is a task that is currently in a
1125 * syscall, then the syscall is marked as auditable and an audit record
1126 * will be written at syscall exit. If there is no associated task, tsk
1127 * should be NULL. */
9ad9ad38 1128
b0dd25a8
RD
1129/**
1130 * audit_log_start - obtain an audit buffer
1131 * @ctx: audit_context (may be NULL)
1132 * @gfp_mask: type of allocation
1133 * @type: audit message type
1134 *
1135 * Returns audit_buffer pointer on success or NULL on error.
1136 *
1137 * Obtain an audit buffer. This routine does locking to obtain the
1138 * audit buffer, but then no locking is required for calls to
1139 * audit_log_*format. If the task (ctx) is a task that is currently in a
1140 * syscall, then the syscall is marked as auditable and an audit record
1141 * will be written at syscall exit. If there is no associated task, then
1142 * task context (ctx) should be NULL.
1143 */
9796fdd8 1144struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
9ad9ad38 1145 int type)
1da177e4
LT
1146{
1147 struct audit_buffer *ab = NULL;
1da177e4 1148 struct timespec t;
ef00be05 1149 unsigned int uninitialized_var(serial);
9ad9ad38 1150 int reserve;
ac4cec44 1151 unsigned long timeout_start = jiffies;
1da177e4 1152
a3f07114 1153 if (audit_initialized != AUDIT_INITIALIZED)
1da177e4
LT
1154 return NULL;
1155
c8edc80c
DK
1156 if (unlikely(audit_filter_type(type)))
1157 return NULL;
1158
9ad9ad38
DW
1159 if (gfp_mask & __GFP_WAIT)
1160 reserve = 0;
1161 else
5600b892 1162 reserve = 5; /* Allow atomic callers to go up to five
9ad9ad38
DW
1163 entries over the normal backlog limit */
1164
1165 while (audit_backlog_limit
1166 && skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) {
ac4cec44
DW
1167 if (gfp_mask & __GFP_WAIT && audit_backlog_wait_time
1168 && time_before(jiffies, timeout_start + audit_backlog_wait_time)) {
1169
9ad9ad38
DW
1170 /* Wait for auditd to drain the queue a little */
1171 DECLARE_WAITQUEUE(wait, current);
1172 set_current_state(TASK_INTERRUPTIBLE);
1173 add_wait_queue(&audit_backlog_wait, &wait);
1174
1175 if (audit_backlog_limit &&
1176 skb_queue_len(&audit_skb_queue) > audit_backlog_limit)
ac4cec44 1177 schedule_timeout(timeout_start + audit_backlog_wait_time - jiffies);
9ad9ad38
DW
1178
1179 __set_current_state(TASK_RUNNING);
1180 remove_wait_queue(&audit_backlog_wait, &wait);
ac4cec44 1181 continue;
9ad9ad38 1182 }
320f1b1e 1183 if (audit_rate_check() && printk_ratelimit())
fb19b4c6
DW
1184 printk(KERN_WARNING
1185 "audit: audit_backlog=%d > "
1186 "audit_backlog_limit=%d\n",
1187 skb_queue_len(&audit_skb_queue),
1188 audit_backlog_limit);
1189 audit_log_lost("backlog limit exceeded");
ac4cec44
DW
1190 audit_backlog_wait_time = audit_backlog_wait_overflow;
1191 wake_up(&audit_backlog_wait);
fb19b4c6
DW
1192 return NULL;
1193 }
1194
9ad9ad38 1195 ab = audit_buffer_alloc(ctx, gfp_mask, type);
1da177e4
LT
1196 if (!ab) {
1197 audit_log_lost("out of memory in audit_log_start");
1198 return NULL;
1199 }
1200
bfb4496e 1201 audit_get_stamp(ab->ctx, &t, &serial);
197c69c6 1202
1da177e4
LT
1203 audit_log_format(ab, "audit(%lu.%03lu:%u): ",
1204 t.tv_sec, t.tv_nsec/1000000, serial);
1205 return ab;
1206}
1207
8fc6115c 1208/**
5ac52f33 1209 * audit_expand - expand skb in the audit buffer
8fc6115c 1210 * @ab: audit_buffer
b0dd25a8 1211 * @extra: space to add at tail of the skb
8fc6115c
CW
1212 *
1213 * Returns 0 (no space) on failed expansion, or available space if
1214 * successful.
1215 */
e3b926b4 1216static inline int audit_expand(struct audit_buffer *ab, int extra)
8fc6115c 1217{
5ac52f33 1218 struct sk_buff *skb = ab->skb;
406a1d86
HX
1219 int oldtail = skb_tailroom(skb);
1220 int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1221 int newtail = skb_tailroom(skb);
1222
5ac52f33
CW
1223 if (ret < 0) {
1224 audit_log_lost("out of memory in audit_expand");
8fc6115c 1225 return 0;
5ac52f33 1226 }
406a1d86
HX
1227
1228 skb->truesize += newtail - oldtail;
1229 return newtail;
8fc6115c 1230}
1da177e4 1231
b0dd25a8
RD
1232/*
1233 * Format an audit message into the audit buffer. If there isn't enough
1da177e4
LT
1234 * room in the audit buffer, more room will be allocated and vsnprint
1235 * will be called a second time. Currently, we assume that a printk
b0dd25a8
RD
1236 * can't format message larger than 1024 bytes, so we don't either.
1237 */
1da177e4
LT
1238static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1239 va_list args)
1240{
1241 int len, avail;
5ac52f33 1242 struct sk_buff *skb;
eecb0a73 1243 va_list args2;
1da177e4
LT
1244
1245 if (!ab)
1246 return;
1247
5ac52f33
CW
1248 BUG_ON(!ab->skb);
1249 skb = ab->skb;
1250 avail = skb_tailroom(skb);
1251 if (avail == 0) {
e3b926b4 1252 avail = audit_expand(ab, AUDIT_BUFSIZ);
8fc6115c
CW
1253 if (!avail)
1254 goto out;
1da177e4 1255 }
eecb0a73 1256 va_copy(args2, args);
27a884dc 1257 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1da177e4
LT
1258 if (len >= avail) {
1259 /* The printk buffer is 1024 bytes long, so if we get
1260 * here and AUDIT_BUFSIZ is at least 1024, then we can
1261 * log everything that printk could have logged. */
b0dd25a8
RD
1262 avail = audit_expand(ab,
1263 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
8fc6115c
CW
1264 if (!avail)
1265 goto out;
27a884dc 1266 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1da177e4 1267 }
148b38dc 1268 va_end(args2);
168b7173
SG
1269 if (len > 0)
1270 skb_put(skb, len);
8fc6115c
CW
1271out:
1272 return;
1da177e4
LT
1273}
1274
b0dd25a8
RD
1275/**
1276 * audit_log_format - format a message into the audit buffer.
1277 * @ab: audit_buffer
1278 * @fmt: format string
1279 * @...: optional parameters matching @fmt string
1280 *
1281 * All the work is done in audit_log_vformat.
1282 */
1da177e4
LT
1283void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1284{
1285 va_list args;
1286
1287 if (!ab)
1288 return;
1289 va_start(args, fmt);
1290 audit_log_vformat(ab, fmt, args);
1291 va_end(args);
1292}
1293
b0dd25a8
RD
1294/**
1295 * audit_log_hex - convert a buffer to hex and append it to the audit skb
1296 * @ab: the audit_buffer
1297 * @buf: buffer to convert to hex
1298 * @len: length of @buf to be converted
1299 *
1300 * No return value; failure to expand is silently ignored.
1301 *
1302 * This function will take the passed buf and convert it into a string of
1303 * ascii hex digits. The new string is placed onto the skb.
1304 */
b556f8ad 1305void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
168b7173 1306 size_t len)
83c7d091 1307{
168b7173
SG
1308 int i, avail, new_len;
1309 unsigned char *ptr;
1310 struct sk_buff *skb;
1311 static const unsigned char *hex = "0123456789ABCDEF";
1312
8ef2d304
AG
1313 if (!ab)
1314 return;
1315
168b7173
SG
1316 BUG_ON(!ab->skb);
1317 skb = ab->skb;
1318 avail = skb_tailroom(skb);
1319 new_len = len<<1;
1320 if (new_len >= avail) {
1321 /* Round the buffer request up to the next multiple */
1322 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1323 avail = audit_expand(ab, new_len);
1324 if (!avail)
1325 return;
1326 }
83c7d091 1327
27a884dc 1328 ptr = skb_tail_pointer(skb);
168b7173
SG
1329 for (i=0; i<len; i++) {
1330 *ptr++ = hex[(buf[i] & 0xF0)>>4]; /* Upper nibble */
1331 *ptr++ = hex[buf[i] & 0x0F]; /* Lower nibble */
1332 }
1333 *ptr = 0;
1334 skb_put(skb, len << 1); /* new string is twice the old string */
83c7d091
DW
1335}
1336
9c937dcc
AG
1337/*
1338 * Format a string of no more than slen characters into the audit buffer,
1339 * enclosed in quote marks.
1340 */
b556f8ad
EP
1341void audit_log_n_string(struct audit_buffer *ab, const char *string,
1342 size_t slen)
9c937dcc
AG
1343{
1344 int avail, new_len;
1345 unsigned char *ptr;
1346 struct sk_buff *skb;
1347
8ef2d304
AG
1348 if (!ab)
1349 return;
1350
9c937dcc
AG
1351 BUG_ON(!ab->skb);
1352 skb = ab->skb;
1353 avail = skb_tailroom(skb);
1354 new_len = slen + 3; /* enclosing quotes + null terminator */
1355 if (new_len > avail) {
1356 avail = audit_expand(ab, new_len);
1357 if (!avail)
1358 return;
1359 }
27a884dc 1360 ptr = skb_tail_pointer(skb);
9c937dcc
AG
1361 *ptr++ = '"';
1362 memcpy(ptr, string, slen);
1363 ptr += slen;
1364 *ptr++ = '"';
1365 *ptr = 0;
1366 skb_put(skb, slen + 2); /* don't include null terminator */
1367}
1368
de6bbd1d
EP
1369/**
1370 * audit_string_contains_control - does a string need to be logged in hex
f706d5d2
DJ
1371 * @string: string to be checked
1372 * @len: max length of the string to check
de6bbd1d
EP
1373 */
1374int audit_string_contains_control(const char *string, size_t len)
1375{
1376 const unsigned char *p;
b3897f56 1377 for (p = string; p < (const unsigned char *)string + len; p++) {
1d6c9649 1378 if (*p == '"' || *p < 0x21 || *p > 0x7e)
de6bbd1d
EP
1379 return 1;
1380 }
1381 return 0;
1382}
1383
b0dd25a8 1384/**
522ed776 1385 * audit_log_n_untrustedstring - log a string that may contain random characters
b0dd25a8 1386 * @ab: audit_buffer
f706d5d2 1387 * @len: length of string (not including trailing null)
b0dd25a8
RD
1388 * @string: string to be logged
1389 *
1390 * This code will escape a string that is passed to it if the string
1391 * contains a control character, unprintable character, double quote mark,
168b7173 1392 * or a space. Unescaped strings will start and end with a double quote mark.
b0dd25a8 1393 * Strings that are escaped are printed in hex (2 digits per char).
9c937dcc
AG
1394 *
1395 * The caller specifies the number of characters in the string to log, which may
1396 * or may not be the entire string.
b0dd25a8 1397 */
b556f8ad
EP
1398void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
1399 size_t len)
83c7d091 1400{
de6bbd1d 1401 if (audit_string_contains_control(string, len))
b556f8ad 1402 audit_log_n_hex(ab, string, len);
de6bbd1d 1403 else
b556f8ad 1404 audit_log_n_string(ab, string, len);
83c7d091
DW
1405}
1406
9c937dcc 1407/**
522ed776 1408 * audit_log_untrustedstring - log a string that may contain random characters
9c937dcc
AG
1409 * @ab: audit_buffer
1410 * @string: string to be logged
1411 *
522ed776 1412 * Same as audit_log_n_untrustedstring(), except that strlen is used to
9c937dcc
AG
1413 * determine string length.
1414 */
de6bbd1d 1415void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
9c937dcc 1416{
b556f8ad 1417 audit_log_n_untrustedstring(ab, string, strlen(string));
9c937dcc
AG
1418}
1419
168b7173 1420/* This is a helper-function to print the escaped d_path */
1da177e4 1421void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
44707fdf 1422 struct path *path)
1da177e4 1423{
44707fdf 1424 char *p, *pathname;
1da177e4 1425
8fc6115c
CW
1426 if (prefix)
1427 audit_log_format(ab, " %s", prefix);
1da177e4 1428
168b7173 1429 /* We will allow 11 spaces for ' (deleted)' to be appended */
44707fdf
JB
1430 pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
1431 if (!pathname) {
def57543 1432 audit_log_string(ab, "<no_memory>");
168b7173 1433 return;
1da177e4 1434 }
cf28b486 1435 p = d_path(path, pathname, PATH_MAX+11);
168b7173
SG
1436 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
1437 /* FIXME: can we save some information here? */
def57543 1438 audit_log_string(ab, "<too_long>");
5600b892 1439 } else
168b7173 1440 audit_log_untrustedstring(ab, p);
44707fdf 1441 kfree(pathname);
1da177e4
LT
1442}
1443
9d960985
EP
1444void audit_log_key(struct audit_buffer *ab, char *key)
1445{
1446 audit_log_format(ab, " key=");
1447 if (key)
1448 audit_log_untrustedstring(ab, key);
1449 else
1450 audit_log_format(ab, "(null)");
1451}
1452
b0dd25a8
RD
1453/**
1454 * audit_log_end - end one audit record
1455 * @ab: the audit_buffer
1456 *
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
1da177e4 1459 * remove them from the queue outside the irq context. May be called in
b0dd25a8
RD
1460 * any context.
1461 */
b7d11258 1462void audit_log_end(struct audit_buffer *ab)
1da177e4 1463{
1da177e4
LT
1464 if (!ab)
1465 return;
1466 if (!audit_rate_check()) {
1467 audit_log_lost("rate limit exceeded");
1468 } else {
8d07a67c 1469 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
f3d357b0
EP
1470 nlh->nlmsg_len = ab->skb->len - NLMSG_SPACE(0);
1471
b7d11258 1472 if (audit_pid) {
b7d11258 1473 skb_queue_tail(&audit_skb_queue, ab->skb);
b7d11258 1474 wake_up_interruptible(&kauditd_wait);
f3d357b0 1475 } else {
038cbcf6 1476 audit_printk_skb(ab->skb);
b7d11258 1477 }
f3d357b0 1478 ab->skb = NULL;
1da177e4 1479 }
16e1904e 1480 audit_buffer_free(ab);
1da177e4
LT
1481}
1482
b0dd25a8
RD
1483/**
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
1490 *
1491 * This is a convenience function that calls audit_log_start,
1492 * audit_log_vformat, and audit_log_end. It may be called
1493 * in any context.
1494 */
5600b892 1495void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
9ad9ad38 1496 const char *fmt, ...)
1da177e4
LT
1497{
1498 struct audit_buffer *ab;
1499 va_list args;
1500
9ad9ad38 1501 ab = audit_log_start(ctx, gfp_mask, type);
1da177e4
LT
1502 if (ab) {
1503 va_start(args, fmt);
1504 audit_log_vformat(ab, fmt, args);
1505 va_end(args);
1506 audit_log_end(ab);
1507 }
1508}
bf45da97 1509
1510EXPORT_SYMBOL(audit_log_start);
1511EXPORT_SYMBOL(audit_log_end);
1512EXPORT_SYMBOL(audit_log_format);
1513EXPORT_SYMBOL(audit_log);