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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 <faith@redhat.com>
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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
45
46 #include <linux/init.h>
47 #include <linux/types.h>
48 #include <linux/atomic.h>
49 #include <linux/mm.h>
50 #include <linux/export.h>
51 #include <linux/slab.h>
52 #include <linux/err.h>
53 #include <linux/kthread.h>
54 #include <linux/kernel.h>
55 #include <linux/syscalls.h>
56
57 #include <linux/audit.h>
58
59 #include <net/sock.h>
60 #include <net/netlink.h>
61 #include <linux/skbuff.h>
62 #ifdef CONFIG_SECURITY
63 #include <linux/security.h>
64 #endif
65 #include <linux/freezer.h>
66 #include <linux/tty.h>
67 #include <linux/pid_namespace.h>
68 #include <net/netns/generic.h>
69
70 #include "audit.h"
71
72 /* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
73 * (Initialization happens after skb_init is called.) */
74 #define AUDIT_DISABLED -1
75 #define AUDIT_UNINITIALIZED 0
76 #define AUDIT_INITIALIZED 1
77 static int audit_initialized;
78
79 #define AUDIT_OFF 0
80 #define AUDIT_ON 1
81 #define AUDIT_LOCKED 2
82 u32 audit_enabled;
83 u32 audit_ever_enabled;
84
85 EXPORT_SYMBOL_GPL(audit_enabled);
86
87 /* Default state when kernel boots without any parameters. */
88 static u32 audit_default;
89
90 /* If auditing cannot proceed, audit_failure selects what happens. */
91 static u32 audit_failure = AUDIT_FAIL_PRINTK;
92
93 /*
94 * If audit records are to be written to the netlink socket, audit_pid
95 * contains the pid of the auditd process and audit_nlk_portid contains
96 * the portid to use to send netlink messages to that process.
97 */
98 int audit_pid;
99 static __u32 audit_nlk_portid;
100
101 /* If audit_rate_limit is non-zero, limit the rate of sending audit records
102 * to that number per second. This prevents DoS attacks, but results in
103 * audit records being dropped. */
104 static u32 audit_rate_limit;
105
106 /* Number of outstanding audit_buffers allowed.
107 * When set to zero, this means unlimited. */
108 static u32 audit_backlog_limit = 64;
109 #define AUDIT_BACKLOG_WAIT_TIME (60 * HZ)
110 static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
111 static u32 audit_backlog_wait_overflow = 0;
112
113 /* The identity of the user shutting down the audit system. */
114 kuid_t audit_sig_uid = INVALID_UID;
115 pid_t audit_sig_pid = -1;
116 u32 audit_sig_sid = 0;
117
118 /* Records can be lost in several ways:
119 0) [suppressed in audit_alloc]
120 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
121 2) out of memory in audit_log_move [alloc_skb]
122 3) suppressed due to audit_rate_limit
123 4) suppressed due to audit_backlog_limit
124 */
125 static atomic_t audit_lost = ATOMIC_INIT(0);
126
127 /* The netlink socket. */
128 static struct sock *audit_sock;
129 int audit_net_id;
130
131 /* Hash for inode-based rules */
132 struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
133
134 /* The audit_freelist is a list of pre-allocated audit buffers (if more
135 * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
136 * being placed on the freelist). */
137 static DEFINE_SPINLOCK(audit_freelist_lock);
138 static int audit_freelist_count;
139 static LIST_HEAD(audit_freelist);
140
141 static struct sk_buff_head audit_skb_queue;
142 /* queue of skbs to send to auditd when/if it comes back */
143 static struct sk_buff_head audit_skb_hold_queue;
144 static struct task_struct *kauditd_task;
145 static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
146 static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
147
148 static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION,
149 .mask = -1,
150 .features = 0,
151 .lock = 0,};
152
153 static char *audit_feature_names[2] = {
154 "only_unset_loginuid",
155 "loginuid_immutable",
156 };
157
158
159 /* Serialize requests from userspace. */
160 DEFINE_MUTEX(audit_cmd_mutex);
161
162 /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
163 * audit records. Since printk uses a 1024 byte buffer, this buffer
164 * should be at least that large. */
165 #define AUDIT_BUFSIZ 1024
166
167 /* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the
168 * audit_freelist. Doing so eliminates many kmalloc/kfree calls. */
169 #define AUDIT_MAXFREE (2*NR_CPUS)
170
171 /* The audit_buffer is used when formatting an audit record. The caller
172 * locks briefly to get the record off the freelist or to allocate the
173 * buffer, and locks briefly to send the buffer to the netlink layer or
174 * to place it on a transmit queue. Multiple audit_buffers can be in
175 * use simultaneously. */
176 struct audit_buffer {
177 struct list_head list;
178 struct sk_buff *skb; /* formatted skb ready to send */
179 struct audit_context *ctx; /* NULL or associated context */
180 gfp_t gfp_mask;
181 };
182
183 struct audit_reply {
184 __u32 portid;
185 struct net *net;
186 struct sk_buff *skb;
187 };
188
189 static void audit_set_portid(struct audit_buffer *ab, __u32 portid)
190 {
191 if (ab) {
192 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
193 nlh->nlmsg_pid = portid;
194 }
195 }
196
197 void audit_panic(const char *message)
198 {
199 switch (audit_failure) {
200 case AUDIT_FAIL_SILENT:
201 break;
202 case AUDIT_FAIL_PRINTK:
203 if (printk_ratelimit())
204 pr_err("%s\n", message);
205 break;
206 case AUDIT_FAIL_PANIC:
207 /* test audit_pid since printk is always losey, why bother? */
208 if (audit_pid)
209 panic("audit: %s\n", message);
210 break;
211 }
212 }
213
214 static inline int audit_rate_check(void)
215 {
216 static unsigned long last_check = 0;
217 static int messages = 0;
218 static DEFINE_SPINLOCK(lock);
219 unsigned long flags;
220 unsigned long now;
221 unsigned long elapsed;
222 int retval = 0;
223
224 if (!audit_rate_limit) return 1;
225
226 spin_lock_irqsave(&lock, flags);
227 if (++messages < audit_rate_limit) {
228 retval = 1;
229 } else {
230 now = jiffies;
231 elapsed = now - last_check;
232 if (elapsed > HZ) {
233 last_check = now;
234 messages = 0;
235 retval = 1;
236 }
237 }
238 spin_unlock_irqrestore(&lock, flags);
239
240 return retval;
241 }
242
243 /**
244 * audit_log_lost - conditionally log lost audit message event
245 * @message: the message stating reason for lost audit message
246 *
247 * Emit at least 1 message per second, even if audit_rate_check is
248 * throttling.
249 * Always increment the lost messages counter.
250 */
251 void audit_log_lost(const char *message)
252 {
253 static unsigned long last_msg = 0;
254 static DEFINE_SPINLOCK(lock);
255 unsigned long flags;
256 unsigned long now;
257 int print;
258
259 atomic_inc(&audit_lost);
260
261 print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
262
263 if (!print) {
264 spin_lock_irqsave(&lock, flags);
265 now = jiffies;
266 if (now - last_msg > HZ) {
267 print = 1;
268 last_msg = now;
269 }
270 spin_unlock_irqrestore(&lock, flags);
271 }
272
273 if (print) {
274 if (printk_ratelimit())
275 pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
276 atomic_read(&audit_lost),
277 audit_rate_limit,
278 audit_backlog_limit);
279 audit_panic(message);
280 }
281 }
282
283 static int audit_log_config_change(char *function_name, u32 new, u32 old,
284 int allow_changes)
285 {
286 struct audit_buffer *ab;
287 int rc = 0;
288
289 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
290 if (unlikely(!ab))
291 return rc;
292 audit_log_format(ab, "%s=%u old=%u", function_name, new, old);
293 audit_log_session_info(ab);
294 rc = audit_log_task_context(ab);
295 if (rc)
296 allow_changes = 0; /* Something weird, deny request */
297 audit_log_format(ab, " res=%d", allow_changes);
298 audit_log_end(ab);
299 return rc;
300 }
301
302 static int audit_do_config_change(char *function_name, u32 *to_change, u32 new)
303 {
304 int allow_changes, rc = 0;
305 u32 old = *to_change;
306
307 /* check if we are locked */
308 if (audit_enabled == AUDIT_LOCKED)
309 allow_changes = 0;
310 else
311 allow_changes = 1;
312
313 if (audit_enabled != AUDIT_OFF) {
314 rc = audit_log_config_change(function_name, new, old, allow_changes);
315 if (rc)
316 allow_changes = 0;
317 }
318
319 /* If we are allowed, make the change */
320 if (allow_changes == 1)
321 *to_change = new;
322 /* Not allowed, update reason */
323 else if (rc == 0)
324 rc = -EPERM;
325 return rc;
326 }
327
328 static int audit_set_rate_limit(u32 limit)
329 {
330 return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit);
331 }
332
333 static int audit_set_backlog_limit(u32 limit)
334 {
335 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit);
336 }
337
338 static int audit_set_backlog_wait_time(u32 timeout)
339 {
340 return audit_do_config_change("audit_backlog_wait_time",
341 &audit_backlog_wait_time, timeout);
342 }
343
344 static int audit_set_enabled(u32 state)
345 {
346 int rc;
347 if (state < AUDIT_OFF || state > AUDIT_LOCKED)
348 return -EINVAL;
349
350 rc = audit_do_config_change("audit_enabled", &audit_enabled, state);
351 if (!rc)
352 audit_ever_enabled |= !!state;
353
354 return rc;
355 }
356
357 static int audit_set_failure(u32 state)
358 {
359 if (state != AUDIT_FAIL_SILENT
360 && state != AUDIT_FAIL_PRINTK
361 && state != AUDIT_FAIL_PANIC)
362 return -EINVAL;
363
364 return audit_do_config_change("audit_failure", &audit_failure, state);
365 }
366
367 /*
368 * Queue skbs to be sent to auditd when/if it comes back. These skbs should
369 * already have been sent via prink/syslog and so if these messages are dropped
370 * it is not a huge concern since we already passed the audit_log_lost()
371 * notification and stuff. This is just nice to get audit messages during
372 * boot before auditd is running or messages generated while auditd is stopped.
373 * This only holds messages is audit_default is set, aka booting with audit=1
374 * or building your kernel that way.
375 */
376 static void audit_hold_skb(struct sk_buff *skb)
377 {
378 if (audit_default &&
379 (!audit_backlog_limit ||
380 skb_queue_len(&audit_skb_hold_queue) < audit_backlog_limit))
381 skb_queue_tail(&audit_skb_hold_queue, skb);
382 else
383 kfree_skb(skb);
384 }
385
386 /*
387 * For one reason or another this nlh isn't getting delivered to the userspace
388 * audit daemon, just send it to printk.
389 */
390 static void audit_printk_skb(struct sk_buff *skb)
391 {
392 struct nlmsghdr *nlh = nlmsg_hdr(skb);
393 char *data = nlmsg_data(nlh);
394
395 if (nlh->nlmsg_type != AUDIT_EOE) {
396 if (printk_ratelimit())
397 pr_notice("type=%d %s\n", nlh->nlmsg_type, data);
398 else
399 audit_log_lost("printk limit exceeded");
400 }
401
402 audit_hold_skb(skb);
403 }
404
405 static void kauditd_send_skb(struct sk_buff *skb)
406 {
407 int err;
408 /* take a reference in case we can't send it and we want to hold it */
409 skb_get(skb);
410 err = netlink_unicast(audit_sock, skb, audit_nlk_portid, 0);
411 if (err < 0) {
412 BUG_ON(err != -ECONNREFUSED); /* Shouldn't happen */
413 if (audit_pid) {
414 pr_err("*NO* daemon at audit_pid=%d\n", audit_pid);
415 audit_log_lost("auditd disappeared");
416 audit_pid = 0;
417 audit_sock = NULL;
418 }
419 /* we might get lucky and get this in the next auditd */
420 audit_hold_skb(skb);
421 } else
422 /* drop the extra reference if sent ok */
423 consume_skb(skb);
424 }
425
426 /*
427 * kauditd_send_multicast_skb - send the skb to multicast userspace listeners
428 *
429 * This function doesn't consume an skb as might be expected since it has to
430 * copy it anyways.
431 */
432 static void kauditd_send_multicast_skb(struct sk_buff *skb)
433 {
434 struct sk_buff *copy;
435 struct audit_net *aunet = net_generic(&init_net, audit_net_id);
436 struct sock *sock = aunet->nlsk;
437
438 if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
439 return;
440
441 /*
442 * The seemingly wasteful skb_copy() rather than bumping the refcount
443 * using skb_get() is necessary because non-standard mods are made to
444 * the skb by the original kaudit unicast socket send routine. The
445 * existing auditd daemon assumes this breakage. Fixing this would
446 * require co-ordinating a change in the established protocol between
447 * the kaudit kernel subsystem and the auditd userspace code. There is
448 * no reason for new multicast clients to continue with this
449 * non-compliance.
450 */
451 copy = skb_copy(skb, GFP_KERNEL);
452 if (!copy)
453 return;
454
455 nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL);
456 }
457
458 /*
459 * flush_hold_queue - empty the hold queue if auditd appears
460 *
461 * If auditd just started, drain the queue of messages already
462 * sent to syslog/printk. Remember loss here is ok. We already
463 * called audit_log_lost() if it didn't go out normally. so the
464 * race between the skb_dequeue and the next check for audit_pid
465 * doesn't matter.
466 *
467 * If you ever find kauditd to be too slow we can get a perf win
468 * by doing our own locking and keeping better track if there
469 * are messages in this queue. I don't see the need now, but
470 * in 5 years when I want to play with this again I'll see this
471 * note and still have no friggin idea what i'm thinking today.
472 */
473 static void flush_hold_queue(void)
474 {
475 struct sk_buff *skb;
476
477 if (!audit_default || !audit_pid)
478 return;
479
480 skb = skb_dequeue(&audit_skb_hold_queue);
481 if (likely(!skb))
482 return;
483
484 while (skb && audit_pid) {
485 kauditd_send_skb(skb);
486 skb = skb_dequeue(&audit_skb_hold_queue);
487 }
488
489 /*
490 * if auditd just disappeared but we
491 * dequeued an skb we need to drop ref
492 */
493 if (skb)
494 consume_skb(skb);
495 }
496
497 static int kauditd_thread(void *dummy)
498 {
499 set_freezable();
500 while (!kthread_should_stop()) {
501 struct sk_buff *skb;
502 DECLARE_WAITQUEUE(wait, current);
503
504 flush_hold_queue();
505
506 skb = skb_dequeue(&audit_skb_queue);
507
508 if (skb) {
509 if (skb_queue_len(&audit_skb_queue) <= audit_backlog_limit)
510 wake_up(&audit_backlog_wait);
511 if (audit_pid)
512 kauditd_send_skb(skb);
513 else
514 audit_printk_skb(skb);
515 continue;
516 }
517 set_current_state(TASK_INTERRUPTIBLE);
518 add_wait_queue(&kauditd_wait, &wait);
519
520 if (!skb_queue_len(&audit_skb_queue)) {
521 try_to_freeze();
522 schedule();
523 }
524
525 __set_current_state(TASK_RUNNING);
526 remove_wait_queue(&kauditd_wait, &wait);
527 }
528 return 0;
529 }
530
531 int audit_send_list(void *_dest)
532 {
533 struct audit_netlink_list *dest = _dest;
534 struct sk_buff *skb;
535 struct net *net = dest->net;
536 struct audit_net *aunet = net_generic(net, audit_net_id);
537
538 /* wait for parent to finish and send an ACK */
539 mutex_lock(&audit_cmd_mutex);
540 mutex_unlock(&audit_cmd_mutex);
541
542 while ((skb = __skb_dequeue(&dest->q)) != NULL)
543 netlink_unicast(aunet->nlsk, skb, dest->portid, 0);
544
545 put_net(net);
546 kfree(dest);
547
548 return 0;
549 }
550
551 struct sk_buff *audit_make_reply(__u32 portid, int seq, int type, int done,
552 int multi, const void *payload, int size)
553 {
554 struct sk_buff *skb;
555 struct nlmsghdr *nlh;
556 void *data;
557 int flags = multi ? NLM_F_MULTI : 0;
558 int t = done ? NLMSG_DONE : type;
559
560 skb = nlmsg_new(size, GFP_KERNEL);
561 if (!skb)
562 return NULL;
563
564 nlh = nlmsg_put(skb, portid, seq, t, size, flags);
565 if (!nlh)
566 goto out_kfree_skb;
567 data = nlmsg_data(nlh);
568 memcpy(data, payload, size);
569 return skb;
570
571 out_kfree_skb:
572 kfree_skb(skb);
573 return NULL;
574 }
575
576 static int audit_send_reply_thread(void *arg)
577 {
578 struct audit_reply *reply = (struct audit_reply *)arg;
579 struct net *net = reply->net;
580 struct audit_net *aunet = net_generic(net, audit_net_id);
581
582 mutex_lock(&audit_cmd_mutex);
583 mutex_unlock(&audit_cmd_mutex);
584
585 /* Ignore failure. It'll only happen if the sender goes away,
586 because our timeout is set to infinite. */
587 netlink_unicast(aunet->nlsk , reply->skb, reply->portid, 0);
588 put_net(net);
589 kfree(reply);
590 return 0;
591 }
592 /**
593 * audit_send_reply - send an audit reply message via netlink
594 * @request_skb: skb of request we are replying to (used to target the reply)
595 * @seq: sequence number
596 * @type: audit message type
597 * @done: done (last) flag
598 * @multi: multi-part message flag
599 * @payload: payload data
600 * @size: payload size
601 *
602 * Allocates an skb, builds the netlink message, and sends it to the port id.
603 * No failure notifications.
604 */
605 static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
606 int multi, const void *payload, int size)
607 {
608 u32 portid = NETLINK_CB(request_skb).portid;
609 struct net *net = sock_net(NETLINK_CB(request_skb).sk);
610 struct sk_buff *skb;
611 struct task_struct *tsk;
612 struct audit_reply *reply = kmalloc(sizeof(struct audit_reply),
613 GFP_KERNEL);
614
615 if (!reply)
616 return;
617
618 skb = audit_make_reply(portid, seq, type, done, multi, payload, size);
619 if (!skb)
620 goto out;
621
622 reply->net = get_net(net);
623 reply->portid = portid;
624 reply->skb = skb;
625
626 tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
627 if (!IS_ERR(tsk))
628 return;
629 kfree_skb(skb);
630 out:
631 kfree(reply);
632 }
633
634 /*
635 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
636 * control messages.
637 */
638 static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
639 {
640 int err = 0;
641
642 /* Only support initial user namespace for now. */
643 /*
644 * We return ECONNREFUSED because it tricks userspace into thinking
645 * that audit was not configured into the kernel. Lots of users
646 * configure their PAM stack (because that's what the distro does)
647 * to reject login if unable to send messages to audit. If we return
648 * ECONNREFUSED the PAM stack thinks the kernel does not have audit
649 * configured in and will let login proceed. If we return EPERM
650 * userspace will reject all logins. This should be removed when we
651 * support non init namespaces!!
652 */
653 if (current_user_ns() != &init_user_ns)
654 return -ECONNREFUSED;
655
656 switch (msg_type) {
657 case AUDIT_LIST:
658 case AUDIT_ADD:
659 case AUDIT_DEL:
660 return -EOPNOTSUPP;
661 case AUDIT_GET:
662 case AUDIT_SET:
663 case AUDIT_GET_FEATURE:
664 case AUDIT_SET_FEATURE:
665 case AUDIT_LIST_RULES:
666 case AUDIT_ADD_RULE:
667 case AUDIT_DEL_RULE:
668 case AUDIT_SIGNAL_INFO:
669 case AUDIT_TTY_GET:
670 case AUDIT_TTY_SET:
671 case AUDIT_TRIM:
672 case AUDIT_MAKE_EQUIV:
673 /* Only support auditd and auditctl in initial pid namespace
674 * for now. */
675 if ((task_active_pid_ns(current) != &init_pid_ns))
676 return -EPERM;
677
678 if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
679 err = -EPERM;
680 break;
681 case AUDIT_USER:
682 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
683 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
684 if (!netlink_capable(skb, CAP_AUDIT_WRITE))
685 err = -EPERM;
686 break;
687 default: /* bad msg */
688 err = -EINVAL;
689 }
690
691 return err;
692 }
693
694 static int audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
695 {
696 int rc = 0;
697 uid_t uid = from_kuid(&init_user_ns, current_uid());
698 pid_t pid = task_tgid_nr(current);
699
700 if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
701 *ab = NULL;
702 return rc;
703 }
704
705 *ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
706 if (unlikely(!*ab))
707 return rc;
708 audit_log_format(*ab, "pid=%d uid=%u", pid, uid);
709 audit_log_session_info(*ab);
710 audit_log_task_context(*ab);
711
712 return rc;
713 }
714
715 int is_audit_feature_set(int i)
716 {
717 return af.features & AUDIT_FEATURE_TO_MASK(i);
718 }
719
720
721 static int audit_get_feature(struct sk_buff *skb)
722 {
723 u32 seq;
724
725 seq = nlmsg_hdr(skb)->nlmsg_seq;
726
727 audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &af, sizeof(af));
728
729 return 0;
730 }
731
732 static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
733 u32 old_lock, u32 new_lock, int res)
734 {
735 struct audit_buffer *ab;
736
737 if (audit_enabled == AUDIT_OFF)
738 return;
739
740 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_FEATURE_CHANGE);
741 audit_log_task_info(ab, current);
742 audit_log_format(ab, "feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
743 audit_feature_names[which], !!old_feature, !!new_feature,
744 !!old_lock, !!new_lock, res);
745 audit_log_end(ab);
746 }
747
748 static int audit_set_feature(struct sk_buff *skb)
749 {
750 struct audit_features *uaf;
751 int i;
752
753 BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > sizeof(audit_feature_names)/sizeof(audit_feature_names[0]));
754 uaf = nlmsg_data(nlmsg_hdr(skb));
755
756 /* if there is ever a version 2 we should handle that here */
757
758 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
759 u32 feature = AUDIT_FEATURE_TO_MASK(i);
760 u32 old_feature, new_feature, old_lock, new_lock;
761
762 /* if we are not changing this feature, move along */
763 if (!(feature & uaf->mask))
764 continue;
765
766 old_feature = af.features & feature;
767 new_feature = uaf->features & feature;
768 new_lock = (uaf->lock | af.lock) & feature;
769 old_lock = af.lock & feature;
770
771 /* are we changing a locked feature? */
772 if (old_lock && (new_feature != old_feature)) {
773 audit_log_feature_change(i, old_feature, new_feature,
774 old_lock, new_lock, 0);
775 return -EPERM;
776 }
777 }
778 /* nothing invalid, do the changes */
779 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
780 u32 feature = AUDIT_FEATURE_TO_MASK(i);
781 u32 old_feature, new_feature, old_lock, new_lock;
782
783 /* if we are not changing this feature, move along */
784 if (!(feature & uaf->mask))
785 continue;
786
787 old_feature = af.features & feature;
788 new_feature = uaf->features & feature;
789 old_lock = af.lock & feature;
790 new_lock = (uaf->lock | af.lock) & feature;
791
792 if (new_feature != old_feature)
793 audit_log_feature_change(i, old_feature, new_feature,
794 old_lock, new_lock, 1);
795
796 if (new_feature)
797 af.features |= feature;
798 else
799 af.features &= ~feature;
800 af.lock |= new_lock;
801 }
802
803 return 0;
804 }
805
806 static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
807 {
808 u32 seq;
809 void *data;
810 int err;
811 struct audit_buffer *ab;
812 u16 msg_type = nlh->nlmsg_type;
813 struct audit_sig_info *sig_data;
814 char *ctx = NULL;
815 u32 len;
816
817 err = audit_netlink_ok(skb, msg_type);
818 if (err)
819 return err;
820
821 /* As soon as there's any sign of userspace auditd,
822 * start kauditd to talk to it */
823 if (!kauditd_task) {
824 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
825 if (IS_ERR(kauditd_task)) {
826 err = PTR_ERR(kauditd_task);
827 kauditd_task = NULL;
828 return err;
829 }
830 }
831 seq = nlh->nlmsg_seq;
832 data = nlmsg_data(nlh);
833
834 switch (msg_type) {
835 case AUDIT_GET: {
836 struct audit_status s;
837 memset(&s, 0, sizeof(s));
838 s.enabled = audit_enabled;
839 s.failure = audit_failure;
840 s.pid = audit_pid;
841 s.rate_limit = audit_rate_limit;
842 s.backlog_limit = audit_backlog_limit;
843 s.lost = atomic_read(&audit_lost);
844 s.backlog = skb_queue_len(&audit_skb_queue);
845 s.version = AUDIT_VERSION_LATEST;
846 s.backlog_wait_time = audit_backlog_wait_time;
847 audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
848 break;
849 }
850 case AUDIT_SET: {
851 struct audit_status s;
852 memset(&s, 0, sizeof(s));
853 /* guard against past and future API changes */
854 memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
855 if (s.mask & AUDIT_STATUS_ENABLED) {
856 err = audit_set_enabled(s.enabled);
857 if (err < 0)
858 return err;
859 }
860 if (s.mask & AUDIT_STATUS_FAILURE) {
861 err = audit_set_failure(s.failure);
862 if (err < 0)
863 return err;
864 }
865 if (s.mask & AUDIT_STATUS_PID) {
866 int new_pid = s.pid;
867
868 if ((!new_pid) && (task_tgid_vnr(current) != audit_pid))
869 return -EACCES;
870 if (audit_enabled != AUDIT_OFF)
871 audit_log_config_change("audit_pid", new_pid, audit_pid, 1);
872 audit_pid = new_pid;
873 audit_nlk_portid = NETLINK_CB(skb).portid;
874 audit_sock = skb->sk;
875 }
876 if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
877 err = audit_set_rate_limit(s.rate_limit);
878 if (err < 0)
879 return err;
880 }
881 if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
882 err = audit_set_backlog_limit(s.backlog_limit);
883 if (err < 0)
884 return err;
885 }
886 if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
887 if (sizeof(s) > (size_t)nlh->nlmsg_len)
888 return -EINVAL;
889 if (s.backlog_wait_time < 0 ||
890 s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
891 return -EINVAL;
892 err = audit_set_backlog_wait_time(s.backlog_wait_time);
893 if (err < 0)
894 return err;
895 }
896 break;
897 }
898 case AUDIT_GET_FEATURE:
899 err = audit_get_feature(skb);
900 if (err)
901 return err;
902 break;
903 case AUDIT_SET_FEATURE:
904 err = audit_set_feature(skb);
905 if (err)
906 return err;
907 break;
908 case AUDIT_USER:
909 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
910 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
911 if (!audit_enabled && msg_type != AUDIT_USER_AVC)
912 return 0;
913
914 err = audit_filter_user(msg_type);
915 if (err == 1) { /* match or error */
916 err = 0;
917 if (msg_type == AUDIT_USER_TTY) {
918 err = tty_audit_push_current();
919 if (err)
920 break;
921 }
922 mutex_unlock(&audit_cmd_mutex);
923 audit_log_common_recv_msg(&ab, msg_type);
924 if (msg_type != AUDIT_USER_TTY)
925 audit_log_format(ab, " msg='%.*s'",
926 AUDIT_MESSAGE_TEXT_MAX,
927 (char *)data);
928 else {
929 int size;
930
931 audit_log_format(ab, " data=");
932 size = nlmsg_len(nlh);
933 if (size > 0 &&
934 ((unsigned char *)data)[size - 1] == '\0')
935 size--;
936 audit_log_n_untrustedstring(ab, data, size);
937 }
938 audit_set_portid(ab, NETLINK_CB(skb).portid);
939 audit_log_end(ab);
940 mutex_lock(&audit_cmd_mutex);
941 }
942 break;
943 case AUDIT_ADD_RULE:
944 case AUDIT_DEL_RULE:
945 if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
946 return -EINVAL;
947 if (audit_enabled == AUDIT_LOCKED) {
948 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
949 audit_log_format(ab, " audit_enabled=%d res=0", audit_enabled);
950 audit_log_end(ab);
951 return -EPERM;
952 }
953 err = audit_rule_change(msg_type, NETLINK_CB(skb).portid,
954 seq, data, nlmsg_len(nlh));
955 break;
956 case AUDIT_LIST_RULES:
957 err = audit_list_rules_send(skb, seq);
958 break;
959 case AUDIT_TRIM:
960 audit_trim_trees();
961 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
962 audit_log_format(ab, " op=trim res=1");
963 audit_log_end(ab);
964 break;
965 case AUDIT_MAKE_EQUIV: {
966 void *bufp = data;
967 u32 sizes[2];
968 size_t msglen = nlmsg_len(nlh);
969 char *old, *new;
970
971 err = -EINVAL;
972 if (msglen < 2 * sizeof(u32))
973 break;
974 memcpy(sizes, bufp, 2 * sizeof(u32));
975 bufp += 2 * sizeof(u32);
976 msglen -= 2 * sizeof(u32);
977 old = audit_unpack_string(&bufp, &msglen, sizes[0]);
978 if (IS_ERR(old)) {
979 err = PTR_ERR(old);
980 break;
981 }
982 new = audit_unpack_string(&bufp, &msglen, sizes[1]);
983 if (IS_ERR(new)) {
984 err = PTR_ERR(new);
985 kfree(old);
986 break;
987 }
988 /* OK, here comes... */
989 err = audit_tag_tree(old, new);
990
991 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
992
993 audit_log_format(ab, " op=make_equiv old=");
994 audit_log_untrustedstring(ab, old);
995 audit_log_format(ab, " new=");
996 audit_log_untrustedstring(ab, new);
997 audit_log_format(ab, " res=%d", !err);
998 audit_log_end(ab);
999 kfree(old);
1000 kfree(new);
1001 break;
1002 }
1003 case AUDIT_SIGNAL_INFO:
1004 len = 0;
1005 if (audit_sig_sid) {
1006 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
1007 if (err)
1008 return err;
1009 }
1010 sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
1011 if (!sig_data) {
1012 if (audit_sig_sid)
1013 security_release_secctx(ctx, len);
1014 return -ENOMEM;
1015 }
1016 sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
1017 sig_data->pid = audit_sig_pid;
1018 if (audit_sig_sid) {
1019 memcpy(sig_data->ctx, ctx, len);
1020 security_release_secctx(ctx, len);
1021 }
1022 audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
1023 sig_data, sizeof(*sig_data) + len);
1024 kfree(sig_data);
1025 break;
1026 case AUDIT_TTY_GET: {
1027 struct audit_tty_status s;
1028 struct task_struct *tsk = current;
1029
1030 spin_lock(&tsk->sighand->siglock);
1031 s.enabled = tsk->signal->audit_tty;
1032 s.log_passwd = tsk->signal->audit_tty_log_passwd;
1033 spin_unlock(&tsk->sighand->siglock);
1034
1035 audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
1036 break;
1037 }
1038 case AUDIT_TTY_SET: {
1039 struct audit_tty_status s, old;
1040 struct task_struct *tsk = current;
1041 struct audit_buffer *ab;
1042
1043 memset(&s, 0, sizeof(s));
1044 /* guard against past and future API changes */
1045 memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
1046 /* check if new data is valid */
1047 if ((s.enabled != 0 && s.enabled != 1) ||
1048 (s.log_passwd != 0 && s.log_passwd != 1))
1049 err = -EINVAL;
1050
1051 spin_lock(&tsk->sighand->siglock);
1052 old.enabled = tsk->signal->audit_tty;
1053 old.log_passwd = tsk->signal->audit_tty_log_passwd;
1054 if (!err) {
1055 tsk->signal->audit_tty = s.enabled;
1056 tsk->signal->audit_tty_log_passwd = s.log_passwd;
1057 }
1058 spin_unlock(&tsk->sighand->siglock);
1059
1060 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1061 audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
1062 " old-log_passwd=%d new-log_passwd=%d res=%d",
1063 old.enabled, s.enabled, old.log_passwd,
1064 s.log_passwd, !err);
1065 audit_log_end(ab);
1066 break;
1067 }
1068 default:
1069 err = -EINVAL;
1070 break;
1071 }
1072
1073 return err < 0 ? err : 0;
1074 }
1075
1076 /*
1077 * Get message from skb. Each message is processed by audit_receive_msg.
1078 * Malformed skbs with wrong length are discarded silently.
1079 */
1080 static void audit_receive_skb(struct sk_buff *skb)
1081 {
1082 struct nlmsghdr *nlh;
1083 /*
1084 * len MUST be signed for nlmsg_next to be able to dec it below 0
1085 * if the nlmsg_len was not aligned
1086 */
1087 int len;
1088 int err;
1089
1090 nlh = nlmsg_hdr(skb);
1091 len = skb->len;
1092
1093 while (nlmsg_ok(nlh, len)) {
1094 err = audit_receive_msg(skb, nlh);
1095 /* if err or if this message says it wants a response */
1096 if (err || (nlh->nlmsg_flags & NLM_F_ACK))
1097 netlink_ack(skb, nlh, err);
1098
1099 nlh = nlmsg_next(nlh, &len);
1100 }
1101 }
1102
1103 /* Receive messages from netlink socket. */
1104 static void audit_receive(struct sk_buff *skb)
1105 {
1106 mutex_lock(&audit_cmd_mutex);
1107 audit_receive_skb(skb);
1108 mutex_unlock(&audit_cmd_mutex);
1109 }
1110
1111 /* Run custom bind function on netlink socket group connect or bind requests. */
1112 static int audit_bind(int group)
1113 {
1114 if (!capable(CAP_AUDIT_READ))
1115 return -EPERM;
1116
1117 return 0;
1118 }
1119
1120 static int __net_init audit_net_init(struct net *net)
1121 {
1122 struct netlink_kernel_cfg cfg = {
1123 .input = audit_receive,
1124 .bind = audit_bind,
1125 .flags = NL_CFG_F_NONROOT_RECV,
1126 .groups = AUDIT_NLGRP_MAX,
1127 };
1128
1129 struct audit_net *aunet = net_generic(net, audit_net_id);
1130
1131 aunet->nlsk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
1132 if (aunet->nlsk == NULL) {
1133 audit_panic("cannot initialize netlink socket in namespace");
1134 return -ENOMEM;
1135 }
1136 aunet->nlsk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
1137 return 0;
1138 }
1139
1140 static void __net_exit audit_net_exit(struct net *net)
1141 {
1142 struct audit_net *aunet = net_generic(net, audit_net_id);
1143 struct sock *sock = aunet->nlsk;
1144 if (sock == audit_sock) {
1145 audit_pid = 0;
1146 audit_sock = NULL;
1147 }
1148
1149 RCU_INIT_POINTER(aunet->nlsk, NULL);
1150 synchronize_net();
1151 netlink_kernel_release(sock);
1152 }
1153
1154 static struct pernet_operations audit_net_ops __net_initdata = {
1155 .init = audit_net_init,
1156 .exit = audit_net_exit,
1157 .id = &audit_net_id,
1158 .size = sizeof(struct audit_net),
1159 };
1160
1161 /* Initialize audit support at boot time. */
1162 static int __init audit_init(void)
1163 {
1164 int i;
1165
1166 if (audit_initialized == AUDIT_DISABLED)
1167 return 0;
1168
1169 pr_info("initializing netlink subsys (%s)\n",
1170 audit_default ? "enabled" : "disabled");
1171 register_pernet_subsys(&audit_net_ops);
1172
1173 skb_queue_head_init(&audit_skb_queue);
1174 skb_queue_head_init(&audit_skb_hold_queue);
1175 audit_initialized = AUDIT_INITIALIZED;
1176 audit_enabled = audit_default;
1177 audit_ever_enabled |= !!audit_default;
1178
1179 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized");
1180
1181 for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
1182 INIT_LIST_HEAD(&audit_inode_hash[i]);
1183
1184 return 0;
1185 }
1186 __initcall(audit_init);
1187
1188 /* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
1189 static int __init audit_enable(char *str)
1190 {
1191 audit_default = !!simple_strtol(str, NULL, 0);
1192 if (!audit_default)
1193 audit_initialized = AUDIT_DISABLED;
1194
1195 pr_info("%s\n", audit_default ?
1196 "enabled (after initialization)" : "disabled (until reboot)");
1197
1198 return 1;
1199 }
1200 __setup("audit=", audit_enable);
1201
1202 /* Process kernel command-line parameter at boot time.
1203 * audit_backlog_limit=<n> */
1204 static int __init audit_backlog_limit_set(char *str)
1205 {
1206 u32 audit_backlog_limit_arg;
1207
1208 pr_info("audit_backlog_limit: ");
1209 if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
1210 pr_cont("using default of %u, unable to parse %s\n",
1211 audit_backlog_limit, str);
1212 return 1;
1213 }
1214
1215 audit_backlog_limit = audit_backlog_limit_arg;
1216 pr_cont("%d\n", audit_backlog_limit);
1217
1218 return 1;
1219 }
1220 __setup("audit_backlog_limit=", audit_backlog_limit_set);
1221
1222 static void audit_buffer_free(struct audit_buffer *ab)
1223 {
1224 unsigned long flags;
1225
1226 if (!ab)
1227 return;
1228
1229 if (ab->skb)
1230 kfree_skb(ab->skb);
1231
1232 spin_lock_irqsave(&audit_freelist_lock, flags);
1233 if (audit_freelist_count > AUDIT_MAXFREE)
1234 kfree(ab);
1235 else {
1236 audit_freelist_count++;
1237 list_add(&ab->list, &audit_freelist);
1238 }
1239 spin_unlock_irqrestore(&audit_freelist_lock, flags);
1240 }
1241
1242 static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx,
1243 gfp_t gfp_mask, int type)
1244 {
1245 unsigned long flags;
1246 struct audit_buffer *ab = NULL;
1247 struct nlmsghdr *nlh;
1248
1249 spin_lock_irqsave(&audit_freelist_lock, flags);
1250 if (!list_empty(&audit_freelist)) {
1251 ab = list_entry(audit_freelist.next,
1252 struct audit_buffer, list);
1253 list_del(&ab->list);
1254 --audit_freelist_count;
1255 }
1256 spin_unlock_irqrestore(&audit_freelist_lock, flags);
1257
1258 if (!ab) {
1259 ab = kmalloc(sizeof(*ab), gfp_mask);
1260 if (!ab)
1261 goto err;
1262 }
1263
1264 ab->ctx = ctx;
1265 ab->gfp_mask = gfp_mask;
1266
1267 ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
1268 if (!ab->skb)
1269 goto err;
1270
1271 nlh = nlmsg_put(ab->skb, 0, 0, type, 0, 0);
1272 if (!nlh)
1273 goto out_kfree_skb;
1274
1275 return ab;
1276
1277 out_kfree_skb:
1278 kfree_skb(ab->skb);
1279 ab->skb = NULL;
1280 err:
1281 audit_buffer_free(ab);
1282 return NULL;
1283 }
1284
1285 /**
1286 * audit_serial - compute a serial number for the audit record
1287 *
1288 * Compute a serial number for the audit record. Audit records are
1289 * written to user-space as soon as they are generated, so a complete
1290 * audit record may be written in several pieces. The timestamp of the
1291 * record and this serial number are used by the user-space tools to
1292 * determine which pieces belong to the same audit record. The
1293 * (timestamp,serial) tuple is unique for each syscall and is live from
1294 * syscall entry to syscall exit.
1295 *
1296 * NOTE: Another possibility is to store the formatted records off the
1297 * audit context (for those records that have a context), and emit them
1298 * all at syscall exit. However, this could delay the reporting of
1299 * significant errors until syscall exit (or never, if the system
1300 * halts).
1301 */
1302 unsigned int audit_serial(void)
1303 {
1304 static DEFINE_SPINLOCK(serial_lock);
1305 static unsigned int serial = 0;
1306
1307 unsigned long flags;
1308 unsigned int ret;
1309
1310 spin_lock_irqsave(&serial_lock, flags);
1311 do {
1312 ret = ++serial;
1313 } while (unlikely(!ret));
1314 spin_unlock_irqrestore(&serial_lock, flags);
1315
1316 return ret;
1317 }
1318
1319 static inline void audit_get_stamp(struct audit_context *ctx,
1320 struct timespec *t, unsigned int *serial)
1321 {
1322 if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
1323 *t = CURRENT_TIME;
1324 *serial = audit_serial();
1325 }
1326 }
1327
1328 /*
1329 * Wait for auditd to drain the queue a little
1330 */
1331 static long wait_for_auditd(long sleep_time)
1332 {
1333 DECLARE_WAITQUEUE(wait, current);
1334 set_current_state(TASK_UNINTERRUPTIBLE);
1335 add_wait_queue_exclusive(&audit_backlog_wait, &wait);
1336
1337 if (audit_backlog_limit &&
1338 skb_queue_len(&audit_skb_queue) > audit_backlog_limit)
1339 sleep_time = schedule_timeout(sleep_time);
1340
1341 __set_current_state(TASK_RUNNING);
1342 remove_wait_queue(&audit_backlog_wait, &wait);
1343
1344 return sleep_time;
1345 }
1346
1347 /**
1348 * audit_log_start - obtain an audit buffer
1349 * @ctx: audit_context (may be NULL)
1350 * @gfp_mask: type of allocation
1351 * @type: audit message type
1352 *
1353 * Returns audit_buffer pointer on success or NULL on error.
1354 *
1355 * Obtain an audit buffer. This routine does locking to obtain the
1356 * audit buffer, but then no locking is required for calls to
1357 * audit_log_*format. If the task (ctx) is a task that is currently in a
1358 * syscall, then the syscall is marked as auditable and an audit record
1359 * will be written at syscall exit. If there is no associated task, then
1360 * task context (ctx) should be NULL.
1361 */
1362 struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1363 int type)
1364 {
1365 struct audit_buffer *ab = NULL;
1366 struct timespec t;
1367 unsigned int uninitialized_var(serial);
1368 int reserve = 5; /* Allow atomic callers to go up to five
1369 entries over the normal backlog limit */
1370 unsigned long timeout_start = jiffies;
1371
1372 if (audit_initialized != AUDIT_INITIALIZED)
1373 return NULL;
1374
1375 if (unlikely(audit_filter_type(type)))
1376 return NULL;
1377
1378 if (gfp_mask & __GFP_WAIT) {
1379 if (audit_pid && audit_pid == current->pid)
1380 gfp_mask &= ~__GFP_WAIT;
1381 else
1382 reserve = 0;
1383 }
1384
1385 while (audit_backlog_limit
1386 && skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) {
1387 if (gfp_mask & __GFP_WAIT && audit_backlog_wait_time) {
1388 long sleep_time;
1389
1390 sleep_time = timeout_start + audit_backlog_wait_time - jiffies;
1391 if (sleep_time > 0) {
1392 sleep_time = wait_for_auditd(sleep_time);
1393 if (sleep_time > 0)
1394 continue;
1395 }
1396 }
1397 if (audit_rate_check() && printk_ratelimit())
1398 pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
1399 skb_queue_len(&audit_skb_queue),
1400 audit_backlog_limit);
1401 audit_log_lost("backlog limit exceeded");
1402 audit_backlog_wait_time = audit_backlog_wait_overflow;
1403 wake_up(&audit_backlog_wait);
1404 return NULL;
1405 }
1406
1407 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
1408
1409 ab = audit_buffer_alloc(ctx, gfp_mask, type);
1410 if (!ab) {
1411 audit_log_lost("out of memory in audit_log_start");
1412 return NULL;
1413 }
1414
1415 audit_get_stamp(ab->ctx, &t, &serial);
1416
1417 audit_log_format(ab, "audit(%lu.%03lu:%u): ",
1418 t.tv_sec, t.tv_nsec/1000000, serial);
1419 return ab;
1420 }
1421
1422 /**
1423 * audit_expand - expand skb in the audit buffer
1424 * @ab: audit_buffer
1425 * @extra: space to add at tail of the skb
1426 *
1427 * Returns 0 (no space) on failed expansion, or available space if
1428 * successful.
1429 */
1430 static inline int audit_expand(struct audit_buffer *ab, int extra)
1431 {
1432 struct sk_buff *skb = ab->skb;
1433 int oldtail = skb_tailroom(skb);
1434 int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1435 int newtail = skb_tailroom(skb);
1436
1437 if (ret < 0) {
1438 audit_log_lost("out of memory in audit_expand");
1439 return 0;
1440 }
1441
1442 skb->truesize += newtail - oldtail;
1443 return newtail;
1444 }
1445
1446 /*
1447 * Format an audit message into the audit buffer. If there isn't enough
1448 * room in the audit buffer, more room will be allocated and vsnprint
1449 * will be called a second time. Currently, we assume that a printk
1450 * can't format message larger than 1024 bytes, so we don't either.
1451 */
1452 static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1453 va_list args)
1454 {
1455 int len, avail;
1456 struct sk_buff *skb;
1457 va_list args2;
1458
1459 if (!ab)
1460 return;
1461
1462 BUG_ON(!ab->skb);
1463 skb = ab->skb;
1464 avail = skb_tailroom(skb);
1465 if (avail == 0) {
1466 avail = audit_expand(ab, AUDIT_BUFSIZ);
1467 if (!avail)
1468 goto out;
1469 }
1470 va_copy(args2, args);
1471 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1472 if (len >= avail) {
1473 /* The printk buffer is 1024 bytes long, so if we get
1474 * here and AUDIT_BUFSIZ is at least 1024, then we can
1475 * log everything that printk could have logged. */
1476 avail = audit_expand(ab,
1477 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1478 if (!avail)
1479 goto out_va_end;
1480 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1481 }
1482 if (len > 0)
1483 skb_put(skb, len);
1484 out_va_end:
1485 va_end(args2);
1486 out:
1487 return;
1488 }
1489
1490 /**
1491 * audit_log_format - format a message into the audit buffer.
1492 * @ab: audit_buffer
1493 * @fmt: format string
1494 * @...: optional parameters matching @fmt string
1495 *
1496 * All the work is done in audit_log_vformat.
1497 */
1498 void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1499 {
1500 va_list args;
1501
1502 if (!ab)
1503 return;
1504 va_start(args, fmt);
1505 audit_log_vformat(ab, fmt, args);
1506 va_end(args);
1507 }
1508
1509 /**
1510 * audit_log_hex - convert a buffer to hex and append it to the audit skb
1511 * @ab: the audit_buffer
1512 * @buf: buffer to convert to hex
1513 * @len: length of @buf to be converted
1514 *
1515 * No return value; failure to expand is silently ignored.
1516 *
1517 * This function will take the passed buf and convert it into a string of
1518 * ascii hex digits. The new string is placed onto the skb.
1519 */
1520 void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
1521 size_t len)
1522 {
1523 int i, avail, new_len;
1524 unsigned char *ptr;
1525 struct sk_buff *skb;
1526
1527 if (!ab)
1528 return;
1529
1530 BUG_ON(!ab->skb);
1531 skb = ab->skb;
1532 avail = skb_tailroom(skb);
1533 new_len = len<<1;
1534 if (new_len >= avail) {
1535 /* Round the buffer request up to the next multiple */
1536 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1537 avail = audit_expand(ab, new_len);
1538 if (!avail)
1539 return;
1540 }
1541
1542 ptr = skb_tail_pointer(skb);
1543 for (i = 0; i < len; i++)
1544 ptr = hex_byte_pack_upper(ptr, buf[i]);
1545 *ptr = 0;
1546 skb_put(skb, len << 1); /* new string is twice the old string */
1547 }
1548
1549 /*
1550 * Format a string of no more than slen characters into the audit buffer,
1551 * enclosed in quote marks.
1552 */
1553 void audit_log_n_string(struct audit_buffer *ab, const char *string,
1554 size_t slen)
1555 {
1556 int avail, new_len;
1557 unsigned char *ptr;
1558 struct sk_buff *skb;
1559
1560 if (!ab)
1561 return;
1562
1563 BUG_ON(!ab->skb);
1564 skb = ab->skb;
1565 avail = skb_tailroom(skb);
1566 new_len = slen + 3; /* enclosing quotes + null terminator */
1567 if (new_len > avail) {
1568 avail = audit_expand(ab, new_len);
1569 if (!avail)
1570 return;
1571 }
1572 ptr = skb_tail_pointer(skb);
1573 *ptr++ = '"';
1574 memcpy(ptr, string, slen);
1575 ptr += slen;
1576 *ptr++ = '"';
1577 *ptr = 0;
1578 skb_put(skb, slen + 2); /* don't include null terminator */
1579 }
1580
1581 /**
1582 * audit_string_contains_control - does a string need to be logged in hex
1583 * @string: string to be checked
1584 * @len: max length of the string to check
1585 */
1586 int audit_string_contains_control(const char *string, size_t len)
1587 {
1588 const unsigned char *p;
1589 for (p = string; p < (const unsigned char *)string + len; p++) {
1590 if (*p == '"' || *p < 0x21 || *p > 0x7e)
1591 return 1;
1592 }
1593 return 0;
1594 }
1595
1596 /**
1597 * audit_log_n_untrustedstring - log a string that may contain random characters
1598 * @ab: audit_buffer
1599 * @len: length of string (not including trailing null)
1600 * @string: string to be logged
1601 *
1602 * This code will escape a string that is passed to it if the string
1603 * contains a control character, unprintable character, double quote mark,
1604 * or a space. Unescaped strings will start and end with a double quote mark.
1605 * Strings that are escaped are printed in hex (2 digits per char).
1606 *
1607 * The caller specifies the number of characters in the string to log, which may
1608 * or may not be the entire string.
1609 */
1610 void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
1611 size_t len)
1612 {
1613 if (audit_string_contains_control(string, len))
1614 audit_log_n_hex(ab, string, len);
1615 else
1616 audit_log_n_string(ab, string, len);
1617 }
1618
1619 /**
1620 * audit_log_untrustedstring - log a string that may contain random characters
1621 * @ab: audit_buffer
1622 * @string: string to be logged
1623 *
1624 * Same as audit_log_n_untrustedstring(), except that strlen is used to
1625 * determine string length.
1626 */
1627 void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
1628 {
1629 audit_log_n_untrustedstring(ab, string, strlen(string));
1630 }
1631
1632 /* This is a helper-function to print the escaped d_path */
1633 void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
1634 const struct path *path)
1635 {
1636 char *p, *pathname;
1637
1638 if (prefix)
1639 audit_log_format(ab, "%s", prefix);
1640
1641 /* We will allow 11 spaces for ' (deleted)' to be appended */
1642 pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
1643 if (!pathname) {
1644 audit_log_string(ab, "<no_memory>");
1645 return;
1646 }
1647 p = d_path(path, pathname, PATH_MAX+11);
1648 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
1649 /* FIXME: can we save some information here? */
1650 audit_log_string(ab, "<too_long>");
1651 } else
1652 audit_log_untrustedstring(ab, p);
1653 kfree(pathname);
1654 }
1655
1656 void audit_log_session_info(struct audit_buffer *ab)
1657 {
1658 unsigned int sessionid = audit_get_sessionid(current);
1659 uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
1660
1661 audit_log_format(ab, " auid=%u ses=%u", auid, sessionid);
1662 }
1663
1664 void audit_log_key(struct audit_buffer *ab, char *key)
1665 {
1666 audit_log_format(ab, " key=");
1667 if (key)
1668 audit_log_untrustedstring(ab, key);
1669 else
1670 audit_log_format(ab, "(null)");
1671 }
1672
1673 void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap)
1674 {
1675 int i;
1676
1677 audit_log_format(ab, " %s=", prefix);
1678 CAP_FOR_EACH_U32(i) {
1679 audit_log_format(ab, "%08x",
1680 cap->cap[(_KERNEL_CAPABILITY_U32S-1) - i]);
1681 }
1682 }
1683
1684 void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
1685 {
1686 kernel_cap_t *perm = &name->fcap.permitted;
1687 kernel_cap_t *inh = &name->fcap.inheritable;
1688 int log = 0;
1689
1690 if (!cap_isclear(*perm)) {
1691 audit_log_cap(ab, "cap_fp", perm);
1692 log = 1;
1693 }
1694 if (!cap_isclear(*inh)) {
1695 audit_log_cap(ab, "cap_fi", inh);
1696 log = 1;
1697 }
1698
1699 if (log)
1700 audit_log_format(ab, " cap_fe=%d cap_fver=%x",
1701 name->fcap.fE, name->fcap_ver);
1702 }
1703
1704 static inline int audit_copy_fcaps(struct audit_names *name,
1705 const struct dentry *dentry)
1706 {
1707 struct cpu_vfs_cap_data caps;
1708 int rc;
1709
1710 if (!dentry)
1711 return 0;
1712
1713 rc = get_vfs_caps_from_disk(dentry, &caps);
1714 if (rc)
1715 return rc;
1716
1717 name->fcap.permitted = caps.permitted;
1718 name->fcap.inheritable = caps.inheritable;
1719 name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
1720 name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >>
1721 VFS_CAP_REVISION_SHIFT;
1722
1723 return 0;
1724 }
1725
1726 /* Copy inode data into an audit_names. */
1727 void audit_copy_inode(struct audit_names *name, const struct dentry *dentry,
1728 const struct inode *inode)
1729 {
1730 name->ino = inode->i_ino;
1731 name->dev = inode->i_sb->s_dev;
1732 name->mode = inode->i_mode;
1733 name->uid = inode->i_uid;
1734 name->gid = inode->i_gid;
1735 name->rdev = inode->i_rdev;
1736 security_inode_getsecid(inode, &name->osid);
1737 audit_copy_fcaps(name, dentry);
1738 }
1739
1740 /**
1741 * audit_log_name - produce AUDIT_PATH record from struct audit_names
1742 * @context: audit_context for the task
1743 * @n: audit_names structure with reportable details
1744 * @path: optional path to report instead of audit_names->name
1745 * @record_num: record number to report when handling a list of names
1746 * @call_panic: optional pointer to int that will be updated if secid fails
1747 */
1748 void audit_log_name(struct audit_context *context, struct audit_names *n,
1749 struct path *path, int record_num, int *call_panic)
1750 {
1751 struct audit_buffer *ab;
1752 ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH);
1753 if (!ab)
1754 return;
1755
1756 audit_log_format(ab, "item=%d", record_num);
1757
1758 if (path)
1759 audit_log_d_path(ab, " name=", path);
1760 else if (n->name) {
1761 switch (n->name_len) {
1762 case AUDIT_NAME_FULL:
1763 /* log the full path */
1764 audit_log_format(ab, " name=");
1765 audit_log_untrustedstring(ab, n->name->name);
1766 break;
1767 case 0:
1768 /* name was specified as a relative path and the
1769 * directory component is the cwd */
1770 audit_log_d_path(ab, " name=", &context->pwd);
1771 break;
1772 default:
1773 /* log the name's directory component */
1774 audit_log_format(ab, " name=");
1775 audit_log_n_untrustedstring(ab, n->name->name,
1776 n->name_len);
1777 }
1778 } else
1779 audit_log_format(ab, " name=(null)");
1780
1781 if (n->ino != (unsigned long)-1) {
1782 audit_log_format(ab, " inode=%lu"
1783 " dev=%02x:%02x mode=%#ho"
1784 " ouid=%u ogid=%u rdev=%02x:%02x",
1785 n->ino,
1786 MAJOR(n->dev),
1787 MINOR(n->dev),
1788 n->mode,
1789 from_kuid(&init_user_ns, n->uid),
1790 from_kgid(&init_user_ns, n->gid),
1791 MAJOR(n->rdev),
1792 MINOR(n->rdev));
1793 }
1794 if (n->osid != 0) {
1795 char *ctx = NULL;
1796 u32 len;
1797 if (security_secid_to_secctx(
1798 n->osid, &ctx, &len)) {
1799 audit_log_format(ab, " osid=%u", n->osid);
1800 if (call_panic)
1801 *call_panic = 2;
1802 } else {
1803 audit_log_format(ab, " obj=%s", ctx);
1804 security_release_secctx(ctx, len);
1805 }
1806 }
1807
1808 /* log the audit_names record type */
1809 audit_log_format(ab, " nametype=");
1810 switch(n->type) {
1811 case AUDIT_TYPE_NORMAL:
1812 audit_log_format(ab, "NORMAL");
1813 break;
1814 case AUDIT_TYPE_PARENT:
1815 audit_log_format(ab, "PARENT");
1816 break;
1817 case AUDIT_TYPE_CHILD_DELETE:
1818 audit_log_format(ab, "DELETE");
1819 break;
1820 case AUDIT_TYPE_CHILD_CREATE:
1821 audit_log_format(ab, "CREATE");
1822 break;
1823 default:
1824 audit_log_format(ab, "UNKNOWN");
1825 break;
1826 }
1827
1828 audit_log_fcaps(ab, n);
1829 audit_log_end(ab);
1830 }
1831
1832 int audit_log_task_context(struct audit_buffer *ab)
1833 {
1834 char *ctx = NULL;
1835 unsigned len;
1836 int error;
1837 u32 sid;
1838
1839 security_task_getsecid(current, &sid);
1840 if (!sid)
1841 return 0;
1842
1843 error = security_secid_to_secctx(sid, &ctx, &len);
1844 if (error) {
1845 if (error != -EINVAL)
1846 goto error_path;
1847 return 0;
1848 }
1849
1850 audit_log_format(ab, " subj=%s", ctx);
1851 security_release_secctx(ctx, len);
1852 return 0;
1853
1854 error_path:
1855 audit_panic("error in audit_log_task_context");
1856 return error;
1857 }
1858 EXPORT_SYMBOL(audit_log_task_context);
1859
1860 void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
1861 {
1862 const struct cred *cred;
1863 char name[sizeof(tsk->comm)];
1864 struct mm_struct *mm = tsk->mm;
1865 char *tty;
1866
1867 if (!ab)
1868 return;
1869
1870 /* tsk == current */
1871 cred = current_cred();
1872
1873 spin_lock_irq(&tsk->sighand->siglock);
1874 if (tsk->signal && tsk->signal->tty && tsk->signal->tty->name)
1875 tty = tsk->signal->tty->name;
1876 else
1877 tty = "(none)";
1878 spin_unlock_irq(&tsk->sighand->siglock);
1879
1880 audit_log_format(ab,
1881 " ppid=%d pid=%d auid=%u uid=%u gid=%u"
1882 " euid=%u suid=%u fsuid=%u"
1883 " egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
1884 task_ppid_nr(tsk),
1885 task_pid_nr(tsk),
1886 from_kuid(&init_user_ns, audit_get_loginuid(tsk)),
1887 from_kuid(&init_user_ns, cred->uid),
1888 from_kgid(&init_user_ns, cred->gid),
1889 from_kuid(&init_user_ns, cred->euid),
1890 from_kuid(&init_user_ns, cred->suid),
1891 from_kuid(&init_user_ns, cred->fsuid),
1892 from_kgid(&init_user_ns, cred->egid),
1893 from_kgid(&init_user_ns, cred->sgid),
1894 from_kgid(&init_user_ns, cred->fsgid),
1895 tty, audit_get_sessionid(tsk));
1896
1897 get_task_comm(name, tsk);
1898 audit_log_format(ab, " comm=");
1899 audit_log_untrustedstring(ab, name);
1900
1901 if (mm) {
1902 down_read(&mm->mmap_sem);
1903 if (mm->exe_file)
1904 audit_log_d_path(ab, " exe=", &mm->exe_file->f_path);
1905 up_read(&mm->mmap_sem);
1906 } else
1907 audit_log_format(ab, " exe=(null)");
1908 audit_log_task_context(ab);
1909 }
1910 EXPORT_SYMBOL(audit_log_task_info);
1911
1912 /**
1913 * audit_log_link_denied - report a link restriction denial
1914 * @operation: specific link opreation
1915 * @link: the path that triggered the restriction
1916 */
1917 void audit_log_link_denied(const char *operation, struct path *link)
1918 {
1919 struct audit_buffer *ab;
1920 struct audit_names *name;
1921
1922 name = kzalloc(sizeof(*name), GFP_NOFS);
1923 if (!name)
1924 return;
1925
1926 /* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */
1927 ab = audit_log_start(current->audit_context, GFP_KERNEL,
1928 AUDIT_ANOM_LINK);
1929 if (!ab)
1930 goto out;
1931 audit_log_format(ab, "op=%s", operation);
1932 audit_log_task_info(ab, current);
1933 audit_log_format(ab, " res=0");
1934 audit_log_end(ab);
1935
1936 /* Generate AUDIT_PATH record with object. */
1937 name->type = AUDIT_TYPE_NORMAL;
1938 audit_copy_inode(name, link->dentry, link->dentry->d_inode);
1939 audit_log_name(current->audit_context, name, link, 0, NULL);
1940 out:
1941 kfree(name);
1942 }
1943
1944 /**
1945 * audit_log_end - end one audit record
1946 * @ab: the audit_buffer
1947 *
1948 * netlink_unicast() cannot be called inside an irq context because it blocks
1949 * (last arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed
1950 * on a queue and a tasklet is scheduled to remove them from the queue outside
1951 * the irq context. May be called in any context.
1952 */
1953 void audit_log_end(struct audit_buffer *ab)
1954 {
1955 if (!ab)
1956 return;
1957 if (!audit_rate_check()) {
1958 audit_log_lost("rate limit exceeded");
1959 } else {
1960 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
1961
1962 kauditd_send_multicast_skb(ab->skb);
1963
1964 /*
1965 * The original kaudit unicast socket sends up messages with
1966 * nlmsg_len set to the payload length rather than the entire
1967 * message length. This breaks the standard set by netlink.
1968 * The existing auditd daemon assumes this breakage. Fixing
1969 * this would require co-ordinating a change in the established
1970 * protocol between the kaudit kernel subsystem and the auditd
1971 * userspace code.
1972 */
1973 nlh->nlmsg_len = ab->skb->len - NLMSG_HDRLEN;
1974
1975 if (audit_pid) {
1976 skb_queue_tail(&audit_skb_queue, ab->skb);
1977 wake_up_interruptible(&kauditd_wait);
1978 } else {
1979 audit_printk_skb(ab->skb);
1980 }
1981 ab->skb = NULL;
1982 }
1983 audit_buffer_free(ab);
1984 }
1985
1986 /**
1987 * audit_log - Log an audit record
1988 * @ctx: audit context
1989 * @gfp_mask: type of allocation
1990 * @type: audit message type
1991 * @fmt: format string to use
1992 * @...: variable parameters matching the format string
1993 *
1994 * This is a convenience function that calls audit_log_start,
1995 * audit_log_vformat, and audit_log_end. It may be called
1996 * in any context.
1997 */
1998 void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
1999 const char *fmt, ...)
2000 {
2001 struct audit_buffer *ab;
2002 va_list args;
2003
2004 ab = audit_log_start(ctx, gfp_mask, type);
2005 if (ab) {
2006 va_start(args, fmt);
2007 audit_log_vformat(ab, fmt, args);
2008 va_end(args);
2009 audit_log_end(ab);
2010 }
2011 }
2012
2013 #ifdef CONFIG_SECURITY
2014 /**
2015 * audit_log_secctx - Converts and logs SELinux context
2016 * @ab: audit_buffer
2017 * @secid: security number
2018 *
2019 * This is a helper function that calls security_secid_to_secctx to convert
2020 * secid to secctx and then adds the (converted) SELinux context to the audit
2021 * log by calling audit_log_format, thus also preventing leak of internal secid
2022 * to userspace. If secid cannot be converted audit_panic is called.
2023 */
2024 void audit_log_secctx(struct audit_buffer *ab, u32 secid)
2025 {
2026 u32 len;
2027 char *secctx;
2028
2029 if (security_secid_to_secctx(secid, &secctx, &len)) {
2030 audit_panic("Cannot convert secid to context");
2031 } else {
2032 audit_log_format(ab, " obj=%s", secctx);
2033 security_release_secctx(secctx, len);
2034 }
2035 }
2036 EXPORT_SYMBOL(audit_log_secctx);
2037 #endif
2038
2039 EXPORT_SYMBOL(audit_log_start);
2040 EXPORT_SYMBOL(audit_log_end);
2041 EXPORT_SYMBOL(audit_log_format);
2042 EXPORT_SYMBOL(audit_log);