xref: /openbmc/linux/kernel/audit.c (revision a06c488d)
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/file.h>
47 #include <linux/init.h>
48 #include <linux/types.h>
49 #include <linux/atomic.h>
50 #include <linux/mm.h>
51 #include <linux/export.h>
52 #include <linux/slab.h>
53 #include <linux/err.h>
54 #include <linux/kthread.h>
55 #include <linux/kernel.h>
56 #include <linux/syscalls.h>
57 
58 #include <linux/audit.h>
59 
60 #include <net/sock.h>
61 #include <net/netlink.h>
62 #include <linux/skbuff.h>
63 #ifdef CONFIG_SECURITY
64 #include <linux/security.h>
65 #endif
66 #include <linux/freezer.h>
67 #include <linux/tty.h>
68 #include <linux/pid_namespace.h>
69 #include <net/netns/generic.h>
70 
71 #include "audit.h"
72 
73 /* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
74  * (Initialization happens after skb_init is called.) */
75 #define AUDIT_DISABLED		-1
76 #define AUDIT_UNINITIALIZED	0
77 #define AUDIT_INITIALIZED	1
78 static int	audit_initialized;
79 
80 #define AUDIT_OFF	0
81 #define AUDIT_ON	1
82 #define AUDIT_LOCKED	2
83 u32		audit_enabled;
84 u32		audit_ever_enabled;
85 
86 EXPORT_SYMBOL_GPL(audit_enabled);
87 
88 /* Default state when kernel boots without any parameters. */
89 static u32	audit_default;
90 
91 /* If auditing cannot proceed, audit_failure selects what happens. */
92 static u32	audit_failure = AUDIT_FAIL_PRINTK;
93 
94 /*
95  * If audit records are to be written to the netlink socket, audit_pid
96  * contains the pid of the auditd process and audit_nlk_portid contains
97  * the portid to use to send netlink messages to that process.
98  */
99 int		audit_pid;
100 static __u32	audit_nlk_portid;
101 
102 /* If audit_rate_limit is non-zero, limit the rate of sending audit records
103  * to that number per second.  This prevents DoS attacks, but results in
104  * audit records being dropped. */
105 static u32	audit_rate_limit;
106 
107 /* Number of outstanding audit_buffers allowed.
108  * When set to zero, this means unlimited. */
109 static u32	audit_backlog_limit = 64;
110 #define AUDIT_BACKLOG_WAIT_TIME (60 * HZ)
111 static u32	audit_backlog_wait_time_master = AUDIT_BACKLOG_WAIT_TIME;
112 static u32	audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
113 
114 /* The identity of the user shutting down the audit system. */
115 kuid_t		audit_sig_uid = INVALID_UID;
116 pid_t		audit_sig_pid = -1;
117 u32		audit_sig_sid = 0;
118 
119 /* Records can be lost in several ways:
120    0) [suppressed in audit_alloc]
121    1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
122    2) out of memory in audit_log_move [alloc_skb]
123    3) suppressed due to audit_rate_limit
124    4) suppressed due to audit_backlog_limit
125 */
126 static atomic_t    audit_lost = ATOMIC_INIT(0);
127 
128 /* The netlink socket. */
129 static struct sock *audit_sock;
130 static int audit_net_id;
131 
132 /* Hash for inode-based rules */
133 struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
134 
135 /* The audit_freelist is a list of pre-allocated audit buffers (if more
136  * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
137  * being placed on the freelist). */
138 static DEFINE_SPINLOCK(audit_freelist_lock);
139 static int	   audit_freelist_count;
140 static LIST_HEAD(audit_freelist);
141 
142 static struct sk_buff_head audit_skb_queue;
143 /* queue of skbs to send to auditd when/if it comes back */
144 static struct sk_buff_head audit_skb_hold_queue;
145 static struct task_struct *kauditd_task;
146 static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
147 static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
148 
149 static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION,
150 				   .mask = -1,
151 				   .features = 0,
152 				   .lock = 0,};
153 
154 static char *audit_feature_names[2] = {
155 	"only_unset_loginuid",
156 	"loginuid_immutable",
157 };
158 
159 
160 /* Serialize requests from userspace. */
161 DEFINE_MUTEX(audit_cmd_mutex);
162 
163 /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
164  * audit records.  Since printk uses a 1024 byte buffer, this buffer
165  * should be at least that large. */
166 #define AUDIT_BUFSIZ 1024
167 
168 /* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the
169  * audit_freelist.  Doing so eliminates many kmalloc/kfree calls. */
170 #define AUDIT_MAXFREE  (2*NR_CPUS)
171 
172 /* The audit_buffer is used when formatting an audit record.  The caller
173  * locks briefly to get the record off the freelist or to allocate the
174  * buffer, and locks briefly to send the buffer to the netlink layer or
175  * to place it on a transmit queue.  Multiple audit_buffers can be in
176  * use simultaneously. */
177 struct audit_buffer {
178 	struct list_head     list;
179 	struct sk_buff       *skb;	/* formatted skb ready to send */
180 	struct audit_context *ctx;	/* NULL or associated context */
181 	gfp_t		     gfp_mask;
182 };
183 
184 struct audit_reply {
185 	__u32 portid;
186 	struct net *net;
187 	struct sk_buff *skb;
188 };
189 
190 static void audit_set_portid(struct audit_buffer *ab, __u32 portid)
191 {
192 	if (ab) {
193 		struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
194 		nlh->nlmsg_pid = portid;
195 	}
196 }
197 
198 void audit_panic(const char *message)
199 {
200 	switch (audit_failure) {
201 	case AUDIT_FAIL_SILENT:
202 		break;
203 	case AUDIT_FAIL_PRINTK:
204 		if (printk_ratelimit())
205 			pr_err("%s\n", message);
206 		break;
207 	case AUDIT_FAIL_PANIC:
208 		/* test audit_pid since printk is always losey, why bother? */
209 		if (audit_pid)
210 			panic("audit: %s\n", message);
211 		break;
212 	}
213 }
214 
215 static inline int audit_rate_check(void)
216 {
217 	static unsigned long	last_check = 0;
218 	static int		messages   = 0;
219 	static DEFINE_SPINLOCK(lock);
220 	unsigned long		flags;
221 	unsigned long		now;
222 	unsigned long		elapsed;
223 	int			retval	   = 0;
224 
225 	if (!audit_rate_limit) return 1;
226 
227 	spin_lock_irqsave(&lock, flags);
228 	if (++messages < audit_rate_limit) {
229 		retval = 1;
230 	} else {
231 		now     = jiffies;
232 		elapsed = now - last_check;
233 		if (elapsed > HZ) {
234 			last_check = now;
235 			messages   = 0;
236 			retval     = 1;
237 		}
238 	}
239 	spin_unlock_irqrestore(&lock, flags);
240 
241 	return retval;
242 }
243 
244 /**
245  * audit_log_lost - conditionally log lost audit message event
246  * @message: the message stating reason for lost audit message
247  *
248  * Emit at least 1 message per second, even if audit_rate_check is
249  * throttling.
250  * Always increment the lost messages counter.
251 */
252 void audit_log_lost(const char *message)
253 {
254 	static unsigned long	last_msg = 0;
255 	static DEFINE_SPINLOCK(lock);
256 	unsigned long		flags;
257 	unsigned long		now;
258 	int			print;
259 
260 	atomic_inc(&audit_lost);
261 
262 	print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
263 
264 	if (!print) {
265 		spin_lock_irqsave(&lock, flags);
266 		now = jiffies;
267 		if (now - last_msg > HZ) {
268 			print = 1;
269 			last_msg = now;
270 		}
271 		spin_unlock_irqrestore(&lock, flags);
272 	}
273 
274 	if (print) {
275 		if (printk_ratelimit())
276 			pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
277 				atomic_read(&audit_lost),
278 				audit_rate_limit,
279 				audit_backlog_limit);
280 		audit_panic(message);
281 	}
282 }
283 
284 static int audit_log_config_change(char *function_name, u32 new, u32 old,
285 				   int allow_changes)
286 {
287 	struct audit_buffer *ab;
288 	int rc = 0;
289 
290 	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
291 	if (unlikely(!ab))
292 		return rc;
293 	audit_log_format(ab, "%s=%u old=%u", function_name, new, old);
294 	audit_log_session_info(ab);
295 	rc = audit_log_task_context(ab);
296 	if (rc)
297 		allow_changes = 0; /* Something weird, deny request */
298 	audit_log_format(ab, " res=%d", allow_changes);
299 	audit_log_end(ab);
300 	return rc;
301 }
302 
303 static int audit_do_config_change(char *function_name, u32 *to_change, u32 new)
304 {
305 	int allow_changes, rc = 0;
306 	u32 old = *to_change;
307 
308 	/* check if we are locked */
309 	if (audit_enabled == AUDIT_LOCKED)
310 		allow_changes = 0;
311 	else
312 		allow_changes = 1;
313 
314 	if (audit_enabled != AUDIT_OFF) {
315 		rc = audit_log_config_change(function_name, new, old, allow_changes);
316 		if (rc)
317 			allow_changes = 0;
318 	}
319 
320 	/* If we are allowed, make the change */
321 	if (allow_changes == 1)
322 		*to_change = new;
323 	/* Not allowed, update reason */
324 	else if (rc == 0)
325 		rc = -EPERM;
326 	return rc;
327 }
328 
329 static int audit_set_rate_limit(u32 limit)
330 {
331 	return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit);
332 }
333 
334 static int audit_set_backlog_limit(u32 limit)
335 {
336 	return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit);
337 }
338 
339 static int audit_set_backlog_wait_time(u32 timeout)
340 {
341 	return audit_do_config_change("audit_backlog_wait_time",
342 				      &audit_backlog_wait_time_master, timeout);
343 }
344 
345 static int audit_set_enabled(u32 state)
346 {
347 	int rc;
348 	if (state > AUDIT_LOCKED)
349 		return -EINVAL;
350 
351 	rc =  audit_do_config_change("audit_enabled", &audit_enabled, state);
352 	if (!rc)
353 		audit_ever_enabled |= !!state;
354 
355 	return rc;
356 }
357 
358 static int audit_set_failure(u32 state)
359 {
360 	if (state != AUDIT_FAIL_SILENT
361 	    && state != AUDIT_FAIL_PRINTK
362 	    && state != AUDIT_FAIL_PANIC)
363 		return -EINVAL;
364 
365 	return audit_do_config_change("audit_failure", &audit_failure, state);
366 }
367 
368 /*
369  * Queue skbs to be sent to auditd when/if it comes back.  These skbs should
370  * already have been sent via prink/syslog and so if these messages are dropped
371  * it is not a huge concern since we already passed the audit_log_lost()
372  * notification and stuff.  This is just nice to get audit messages during
373  * boot before auditd is running or messages generated while auditd is stopped.
374  * This only holds messages is audit_default is set, aka booting with audit=1
375  * or building your kernel that way.
376  */
377 static void audit_hold_skb(struct sk_buff *skb)
378 {
379 	if (audit_default &&
380 	    (!audit_backlog_limit ||
381 	     skb_queue_len(&audit_skb_hold_queue) < audit_backlog_limit))
382 		skb_queue_tail(&audit_skb_hold_queue, skb);
383 	else
384 		kfree_skb(skb);
385 }
386 
387 /*
388  * For one reason or another this nlh isn't getting delivered to the userspace
389  * audit daemon, just send it to printk.
390  */
391 static void audit_printk_skb(struct sk_buff *skb)
392 {
393 	struct nlmsghdr *nlh = nlmsg_hdr(skb);
394 	char *data = nlmsg_data(nlh);
395 
396 	if (nlh->nlmsg_type != AUDIT_EOE) {
397 		if (printk_ratelimit())
398 			pr_notice("type=%d %s\n", nlh->nlmsg_type, data);
399 		else
400 			audit_log_lost("printk limit exceeded");
401 	}
402 
403 	audit_hold_skb(skb);
404 }
405 
406 static void kauditd_send_skb(struct sk_buff *skb)
407 {
408 	int err;
409 	int attempts = 0;
410 #define AUDITD_RETRIES 5
411 
412 restart:
413 	/* take a reference in case we can't send it and we want to hold it */
414 	skb_get(skb);
415 	err = netlink_unicast(audit_sock, skb, audit_nlk_portid, 0);
416 	if (err < 0) {
417 		pr_err("netlink_unicast sending to audit_pid=%d returned error: %d\n",
418 		       audit_pid, err);
419 		if (audit_pid) {
420 			if (err == -ECONNREFUSED || err == -EPERM
421 			    || ++attempts >= AUDITD_RETRIES) {
422 				char s[32];
423 
424 				snprintf(s, sizeof(s), "audit_pid=%d reset", audit_pid);
425 				audit_log_lost(s);
426 				audit_pid = 0;
427 				audit_sock = NULL;
428 			} else {
429 				pr_warn("re-scheduling(#%d) write to audit_pid=%d\n",
430 					attempts, audit_pid);
431 				set_current_state(TASK_INTERRUPTIBLE);
432 				schedule();
433 				__set_current_state(TASK_RUNNING);
434 				goto restart;
435 			}
436 		}
437 		/* we might get lucky and get this in the next auditd */
438 		audit_hold_skb(skb);
439 	} else
440 		/* drop the extra reference if sent ok */
441 		consume_skb(skb);
442 }
443 
444 /*
445  * kauditd_send_multicast_skb - send the skb to multicast userspace listeners
446  *
447  * This function doesn't consume an skb as might be expected since it has to
448  * copy it anyways.
449  */
450 static void kauditd_send_multicast_skb(struct sk_buff *skb, gfp_t gfp_mask)
451 {
452 	struct sk_buff		*copy;
453 	struct audit_net	*aunet = net_generic(&init_net, audit_net_id);
454 	struct sock		*sock = aunet->nlsk;
455 
456 	if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
457 		return;
458 
459 	/*
460 	 * The seemingly wasteful skb_copy() rather than bumping the refcount
461 	 * using skb_get() is necessary because non-standard mods are made to
462 	 * the skb by the original kaudit unicast socket send routine.  The
463 	 * existing auditd daemon assumes this breakage.  Fixing this would
464 	 * require co-ordinating a change in the established protocol between
465 	 * the kaudit kernel subsystem and the auditd userspace code.  There is
466 	 * no reason for new multicast clients to continue with this
467 	 * non-compliance.
468 	 */
469 	copy = skb_copy(skb, gfp_mask);
470 	if (!copy)
471 		return;
472 
473 	nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, gfp_mask);
474 }
475 
476 /*
477  * flush_hold_queue - empty the hold queue if auditd appears
478  *
479  * If auditd just started, drain the queue of messages already
480  * sent to syslog/printk.  Remember loss here is ok.  We already
481  * called audit_log_lost() if it didn't go out normally.  so the
482  * race between the skb_dequeue and the next check for audit_pid
483  * doesn't matter.
484  *
485  * If you ever find kauditd to be too slow we can get a perf win
486  * by doing our own locking and keeping better track if there
487  * are messages in this queue.  I don't see the need now, but
488  * in 5 years when I want to play with this again I'll see this
489  * note and still have no friggin idea what i'm thinking today.
490  */
491 static void flush_hold_queue(void)
492 {
493 	struct sk_buff *skb;
494 
495 	if (!audit_default || !audit_pid)
496 		return;
497 
498 	skb = skb_dequeue(&audit_skb_hold_queue);
499 	if (likely(!skb))
500 		return;
501 
502 	while (skb && audit_pid) {
503 		kauditd_send_skb(skb);
504 		skb = skb_dequeue(&audit_skb_hold_queue);
505 	}
506 
507 	/*
508 	 * if auditd just disappeared but we
509 	 * dequeued an skb we need to drop ref
510 	 */
511 	consume_skb(skb);
512 }
513 
514 static int kauditd_thread(void *dummy)
515 {
516 	set_freezable();
517 	while (!kthread_should_stop()) {
518 		struct sk_buff *skb;
519 
520 		flush_hold_queue();
521 
522 		skb = skb_dequeue(&audit_skb_queue);
523 
524 		if (skb) {
525 			if (!audit_backlog_limit ||
526 			    (skb_queue_len(&audit_skb_queue) <= audit_backlog_limit))
527 				wake_up(&audit_backlog_wait);
528 			if (audit_pid)
529 				kauditd_send_skb(skb);
530 			else
531 				audit_printk_skb(skb);
532 			continue;
533 		}
534 
535 		wait_event_freezable(kauditd_wait, skb_queue_len(&audit_skb_queue));
536 	}
537 	return 0;
538 }
539 
540 int audit_send_list(void *_dest)
541 {
542 	struct audit_netlink_list *dest = _dest;
543 	struct sk_buff *skb;
544 	struct net *net = dest->net;
545 	struct audit_net *aunet = net_generic(net, audit_net_id);
546 
547 	/* wait for parent to finish and send an ACK */
548 	mutex_lock(&audit_cmd_mutex);
549 	mutex_unlock(&audit_cmd_mutex);
550 
551 	while ((skb = __skb_dequeue(&dest->q)) != NULL)
552 		netlink_unicast(aunet->nlsk, skb, dest->portid, 0);
553 
554 	put_net(net);
555 	kfree(dest);
556 
557 	return 0;
558 }
559 
560 struct sk_buff *audit_make_reply(__u32 portid, int seq, int type, int done,
561 				 int multi, const void *payload, int size)
562 {
563 	struct sk_buff	*skb;
564 	struct nlmsghdr	*nlh;
565 	void		*data;
566 	int		flags = multi ? NLM_F_MULTI : 0;
567 	int		t     = done  ? NLMSG_DONE  : type;
568 
569 	skb = nlmsg_new(size, GFP_KERNEL);
570 	if (!skb)
571 		return NULL;
572 
573 	nlh	= nlmsg_put(skb, portid, seq, t, size, flags);
574 	if (!nlh)
575 		goto out_kfree_skb;
576 	data = nlmsg_data(nlh);
577 	memcpy(data, payload, size);
578 	return skb;
579 
580 out_kfree_skb:
581 	kfree_skb(skb);
582 	return NULL;
583 }
584 
585 static int audit_send_reply_thread(void *arg)
586 {
587 	struct audit_reply *reply = (struct audit_reply *)arg;
588 	struct net *net = reply->net;
589 	struct audit_net *aunet = net_generic(net, audit_net_id);
590 
591 	mutex_lock(&audit_cmd_mutex);
592 	mutex_unlock(&audit_cmd_mutex);
593 
594 	/* Ignore failure. It'll only happen if the sender goes away,
595 	   because our timeout is set to infinite. */
596 	netlink_unicast(aunet->nlsk , reply->skb, reply->portid, 0);
597 	put_net(net);
598 	kfree(reply);
599 	return 0;
600 }
601 /**
602  * audit_send_reply - send an audit reply message via netlink
603  * @request_skb: skb of request we are replying to (used to target the reply)
604  * @seq: sequence number
605  * @type: audit message type
606  * @done: done (last) flag
607  * @multi: multi-part message flag
608  * @payload: payload data
609  * @size: payload size
610  *
611  * Allocates an skb, builds the netlink message, and sends it to the port id.
612  * No failure notifications.
613  */
614 static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
615 			     int multi, const void *payload, int size)
616 {
617 	u32 portid = NETLINK_CB(request_skb).portid;
618 	struct net *net = sock_net(NETLINK_CB(request_skb).sk);
619 	struct sk_buff *skb;
620 	struct task_struct *tsk;
621 	struct audit_reply *reply = kmalloc(sizeof(struct audit_reply),
622 					    GFP_KERNEL);
623 
624 	if (!reply)
625 		return;
626 
627 	skb = audit_make_reply(portid, seq, type, done, multi, payload, size);
628 	if (!skb)
629 		goto out;
630 
631 	reply->net = get_net(net);
632 	reply->portid = portid;
633 	reply->skb = skb;
634 
635 	tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
636 	if (!IS_ERR(tsk))
637 		return;
638 	kfree_skb(skb);
639 out:
640 	kfree(reply);
641 }
642 
643 /*
644  * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
645  * control messages.
646  */
647 static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
648 {
649 	int err = 0;
650 
651 	/* Only support initial user namespace for now. */
652 	/*
653 	 * We return ECONNREFUSED because it tricks userspace into thinking
654 	 * that audit was not configured into the kernel.  Lots of users
655 	 * configure their PAM stack (because that's what the distro does)
656 	 * to reject login if unable to send messages to audit.  If we return
657 	 * ECONNREFUSED the PAM stack thinks the kernel does not have audit
658 	 * configured in and will let login proceed.  If we return EPERM
659 	 * userspace will reject all logins.  This should be removed when we
660 	 * support non init namespaces!!
661 	 */
662 	if (current_user_ns() != &init_user_ns)
663 		return -ECONNREFUSED;
664 
665 	switch (msg_type) {
666 	case AUDIT_LIST:
667 	case AUDIT_ADD:
668 	case AUDIT_DEL:
669 		return -EOPNOTSUPP;
670 	case AUDIT_GET:
671 	case AUDIT_SET:
672 	case AUDIT_GET_FEATURE:
673 	case AUDIT_SET_FEATURE:
674 	case AUDIT_LIST_RULES:
675 	case AUDIT_ADD_RULE:
676 	case AUDIT_DEL_RULE:
677 	case AUDIT_SIGNAL_INFO:
678 	case AUDIT_TTY_GET:
679 	case AUDIT_TTY_SET:
680 	case AUDIT_TRIM:
681 	case AUDIT_MAKE_EQUIV:
682 		/* Only support auditd and auditctl in initial pid namespace
683 		 * for now. */
684 		if (task_active_pid_ns(current) != &init_pid_ns)
685 			return -EPERM;
686 
687 		if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
688 			err = -EPERM;
689 		break;
690 	case AUDIT_USER:
691 	case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
692 	case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
693 		if (!netlink_capable(skb, CAP_AUDIT_WRITE))
694 			err = -EPERM;
695 		break;
696 	default:  /* bad msg */
697 		err = -EINVAL;
698 	}
699 
700 	return err;
701 }
702 
703 static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
704 {
705 	uid_t uid = from_kuid(&init_user_ns, current_uid());
706 	pid_t pid = task_tgid_nr(current);
707 
708 	if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
709 		*ab = NULL;
710 		return;
711 	}
712 
713 	*ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
714 	if (unlikely(!*ab))
715 		return;
716 	audit_log_format(*ab, "pid=%d uid=%u", pid, uid);
717 	audit_log_session_info(*ab);
718 	audit_log_task_context(*ab);
719 }
720 
721 int is_audit_feature_set(int i)
722 {
723 	return af.features & AUDIT_FEATURE_TO_MASK(i);
724 }
725 
726 
727 static int audit_get_feature(struct sk_buff *skb)
728 {
729 	u32 seq;
730 
731 	seq = nlmsg_hdr(skb)->nlmsg_seq;
732 
733 	audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af));
734 
735 	return 0;
736 }
737 
738 static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
739 				     u32 old_lock, u32 new_lock, int res)
740 {
741 	struct audit_buffer *ab;
742 
743 	if (audit_enabled == AUDIT_OFF)
744 		return;
745 
746 	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_FEATURE_CHANGE);
747 	audit_log_task_info(ab, current);
748 	audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
749 			 audit_feature_names[which], !!old_feature, !!new_feature,
750 			 !!old_lock, !!new_lock, res);
751 	audit_log_end(ab);
752 }
753 
754 static int audit_set_feature(struct sk_buff *skb)
755 {
756 	struct audit_features *uaf;
757 	int i;
758 
759 	BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
760 	uaf = nlmsg_data(nlmsg_hdr(skb));
761 
762 	/* if there is ever a version 2 we should handle that here */
763 
764 	for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
765 		u32 feature = AUDIT_FEATURE_TO_MASK(i);
766 		u32 old_feature, new_feature, old_lock, new_lock;
767 
768 		/* if we are not changing this feature, move along */
769 		if (!(feature & uaf->mask))
770 			continue;
771 
772 		old_feature = af.features & feature;
773 		new_feature = uaf->features & feature;
774 		new_lock = (uaf->lock | af.lock) & feature;
775 		old_lock = af.lock & feature;
776 
777 		/* are we changing a locked feature? */
778 		if (old_lock && (new_feature != old_feature)) {
779 			audit_log_feature_change(i, old_feature, new_feature,
780 						 old_lock, new_lock, 0);
781 			return -EPERM;
782 		}
783 	}
784 	/* nothing invalid, do the changes */
785 	for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
786 		u32 feature = AUDIT_FEATURE_TO_MASK(i);
787 		u32 old_feature, new_feature, old_lock, new_lock;
788 
789 		/* if we are not changing this feature, move along */
790 		if (!(feature & uaf->mask))
791 			continue;
792 
793 		old_feature = af.features & feature;
794 		new_feature = uaf->features & feature;
795 		old_lock = af.lock & feature;
796 		new_lock = (uaf->lock | af.lock) & feature;
797 
798 		if (new_feature != old_feature)
799 			audit_log_feature_change(i, old_feature, new_feature,
800 						 old_lock, new_lock, 1);
801 
802 		if (new_feature)
803 			af.features |= feature;
804 		else
805 			af.features &= ~feature;
806 		af.lock |= new_lock;
807 	}
808 
809 	return 0;
810 }
811 
812 static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
813 {
814 	u32			seq;
815 	void			*data;
816 	int			err;
817 	struct audit_buffer	*ab;
818 	u16			msg_type = nlh->nlmsg_type;
819 	struct audit_sig_info   *sig_data;
820 	char			*ctx = NULL;
821 	u32			len;
822 
823 	err = audit_netlink_ok(skb, msg_type);
824 	if (err)
825 		return err;
826 
827 	/* As soon as there's any sign of userspace auditd,
828 	 * start kauditd to talk to it */
829 	if (!kauditd_task) {
830 		kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
831 		if (IS_ERR(kauditd_task)) {
832 			err = PTR_ERR(kauditd_task);
833 			kauditd_task = NULL;
834 			return err;
835 		}
836 	}
837 	seq  = nlh->nlmsg_seq;
838 	data = nlmsg_data(nlh);
839 
840 	switch (msg_type) {
841 	case AUDIT_GET: {
842 		struct audit_status	s;
843 		memset(&s, 0, sizeof(s));
844 		s.enabled		= audit_enabled;
845 		s.failure		= audit_failure;
846 		s.pid			= audit_pid;
847 		s.rate_limit		= audit_rate_limit;
848 		s.backlog_limit		= audit_backlog_limit;
849 		s.lost			= atomic_read(&audit_lost);
850 		s.backlog		= skb_queue_len(&audit_skb_queue);
851 		s.feature_bitmap	= AUDIT_FEATURE_BITMAP_ALL;
852 		s.backlog_wait_time	= audit_backlog_wait_time_master;
853 		audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
854 		break;
855 	}
856 	case AUDIT_SET: {
857 		struct audit_status	s;
858 		memset(&s, 0, sizeof(s));
859 		/* guard against past and future API changes */
860 		memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
861 		if (s.mask & AUDIT_STATUS_ENABLED) {
862 			err = audit_set_enabled(s.enabled);
863 			if (err < 0)
864 				return err;
865 		}
866 		if (s.mask & AUDIT_STATUS_FAILURE) {
867 			err = audit_set_failure(s.failure);
868 			if (err < 0)
869 				return err;
870 		}
871 		if (s.mask & AUDIT_STATUS_PID) {
872 			int new_pid = s.pid;
873 
874 			if ((!new_pid) && (task_tgid_vnr(current) != audit_pid))
875 				return -EACCES;
876 			if (audit_enabled != AUDIT_OFF)
877 				audit_log_config_change("audit_pid", new_pid, audit_pid, 1);
878 			audit_pid = new_pid;
879 			audit_nlk_portid = NETLINK_CB(skb).portid;
880 			audit_sock = skb->sk;
881 		}
882 		if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
883 			err = audit_set_rate_limit(s.rate_limit);
884 			if (err < 0)
885 				return err;
886 		}
887 		if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
888 			err = audit_set_backlog_limit(s.backlog_limit);
889 			if (err < 0)
890 				return err;
891 		}
892 		if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
893 			if (sizeof(s) > (size_t)nlh->nlmsg_len)
894 				return -EINVAL;
895 			if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
896 				return -EINVAL;
897 			err = audit_set_backlog_wait_time(s.backlog_wait_time);
898 			if (err < 0)
899 				return err;
900 		}
901 		break;
902 	}
903 	case AUDIT_GET_FEATURE:
904 		err = audit_get_feature(skb);
905 		if (err)
906 			return err;
907 		break;
908 	case AUDIT_SET_FEATURE:
909 		err = audit_set_feature(skb);
910 		if (err)
911 			return err;
912 		break;
913 	case AUDIT_USER:
914 	case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
915 	case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
916 		if (!audit_enabled && msg_type != AUDIT_USER_AVC)
917 			return 0;
918 
919 		err = audit_filter_user(msg_type);
920 		if (err == 1) { /* match or error */
921 			err = 0;
922 			if (msg_type == AUDIT_USER_TTY) {
923 				err = tty_audit_push_current();
924 				if (err)
925 					break;
926 			}
927 			mutex_unlock(&audit_cmd_mutex);
928 			audit_log_common_recv_msg(&ab, msg_type);
929 			if (msg_type != AUDIT_USER_TTY)
930 				audit_log_format(ab, " msg='%.*s'",
931 						 AUDIT_MESSAGE_TEXT_MAX,
932 						 (char *)data);
933 			else {
934 				int size;
935 
936 				audit_log_format(ab, " data=");
937 				size = nlmsg_len(nlh);
938 				if (size > 0 &&
939 				    ((unsigned char *)data)[size - 1] == '\0')
940 					size--;
941 				audit_log_n_untrustedstring(ab, data, size);
942 			}
943 			audit_set_portid(ab, NETLINK_CB(skb).portid);
944 			audit_log_end(ab);
945 			mutex_lock(&audit_cmd_mutex);
946 		}
947 		break;
948 	case AUDIT_ADD_RULE:
949 	case AUDIT_DEL_RULE:
950 		if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
951 			return -EINVAL;
952 		if (audit_enabled == AUDIT_LOCKED) {
953 			audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
954 			audit_log_format(ab, " audit_enabled=%d res=0", audit_enabled);
955 			audit_log_end(ab);
956 			return -EPERM;
957 		}
958 		err = audit_rule_change(msg_type, NETLINK_CB(skb).portid,
959 					   seq, data, nlmsg_len(nlh));
960 		break;
961 	case AUDIT_LIST_RULES:
962 		err = audit_list_rules_send(skb, seq);
963 		break;
964 	case AUDIT_TRIM:
965 		audit_trim_trees();
966 		audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
967 		audit_log_format(ab, " op=trim res=1");
968 		audit_log_end(ab);
969 		break;
970 	case AUDIT_MAKE_EQUIV: {
971 		void *bufp = data;
972 		u32 sizes[2];
973 		size_t msglen = nlmsg_len(nlh);
974 		char *old, *new;
975 
976 		err = -EINVAL;
977 		if (msglen < 2 * sizeof(u32))
978 			break;
979 		memcpy(sizes, bufp, 2 * sizeof(u32));
980 		bufp += 2 * sizeof(u32);
981 		msglen -= 2 * sizeof(u32);
982 		old = audit_unpack_string(&bufp, &msglen, sizes[0]);
983 		if (IS_ERR(old)) {
984 			err = PTR_ERR(old);
985 			break;
986 		}
987 		new = audit_unpack_string(&bufp, &msglen, sizes[1]);
988 		if (IS_ERR(new)) {
989 			err = PTR_ERR(new);
990 			kfree(old);
991 			break;
992 		}
993 		/* OK, here comes... */
994 		err = audit_tag_tree(old, new);
995 
996 		audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
997 
998 		audit_log_format(ab, " op=make_equiv old=");
999 		audit_log_untrustedstring(ab, old);
1000 		audit_log_format(ab, " new=");
1001 		audit_log_untrustedstring(ab, new);
1002 		audit_log_format(ab, " res=%d", !err);
1003 		audit_log_end(ab);
1004 		kfree(old);
1005 		kfree(new);
1006 		break;
1007 	}
1008 	case AUDIT_SIGNAL_INFO:
1009 		len = 0;
1010 		if (audit_sig_sid) {
1011 			err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
1012 			if (err)
1013 				return err;
1014 		}
1015 		sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
1016 		if (!sig_data) {
1017 			if (audit_sig_sid)
1018 				security_release_secctx(ctx, len);
1019 			return -ENOMEM;
1020 		}
1021 		sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
1022 		sig_data->pid = audit_sig_pid;
1023 		if (audit_sig_sid) {
1024 			memcpy(sig_data->ctx, ctx, len);
1025 			security_release_secctx(ctx, len);
1026 		}
1027 		audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
1028 				 sig_data, sizeof(*sig_data) + len);
1029 		kfree(sig_data);
1030 		break;
1031 	case AUDIT_TTY_GET: {
1032 		struct audit_tty_status s;
1033 		struct task_struct *tsk = current;
1034 
1035 		spin_lock(&tsk->sighand->siglock);
1036 		s.enabled = tsk->signal->audit_tty;
1037 		s.log_passwd = tsk->signal->audit_tty_log_passwd;
1038 		spin_unlock(&tsk->sighand->siglock);
1039 
1040 		audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
1041 		break;
1042 	}
1043 	case AUDIT_TTY_SET: {
1044 		struct audit_tty_status s, old;
1045 		struct task_struct *tsk = current;
1046 		struct audit_buffer	*ab;
1047 
1048 		memset(&s, 0, sizeof(s));
1049 		/* guard against past and future API changes */
1050 		memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
1051 		/* check if new data is valid */
1052 		if ((s.enabled != 0 && s.enabled != 1) ||
1053 		    (s.log_passwd != 0 && s.log_passwd != 1))
1054 			err = -EINVAL;
1055 
1056 		spin_lock(&tsk->sighand->siglock);
1057 		old.enabled = tsk->signal->audit_tty;
1058 		old.log_passwd = tsk->signal->audit_tty_log_passwd;
1059 		if (!err) {
1060 			tsk->signal->audit_tty = s.enabled;
1061 			tsk->signal->audit_tty_log_passwd = s.log_passwd;
1062 		}
1063 		spin_unlock(&tsk->sighand->siglock);
1064 
1065 		audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1066 		audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
1067 				 " old-log_passwd=%d new-log_passwd=%d res=%d",
1068 				 old.enabled, s.enabled, old.log_passwd,
1069 				 s.log_passwd, !err);
1070 		audit_log_end(ab);
1071 		break;
1072 	}
1073 	default:
1074 		err = -EINVAL;
1075 		break;
1076 	}
1077 
1078 	return err < 0 ? err : 0;
1079 }
1080 
1081 /*
1082  * Get message from skb.  Each message is processed by audit_receive_msg.
1083  * Malformed skbs with wrong length are discarded silently.
1084  */
1085 static void audit_receive_skb(struct sk_buff *skb)
1086 {
1087 	struct nlmsghdr *nlh;
1088 	/*
1089 	 * len MUST be signed for nlmsg_next to be able to dec it below 0
1090 	 * if the nlmsg_len was not aligned
1091 	 */
1092 	int len;
1093 	int err;
1094 
1095 	nlh = nlmsg_hdr(skb);
1096 	len = skb->len;
1097 
1098 	while (nlmsg_ok(nlh, len)) {
1099 		err = audit_receive_msg(skb, nlh);
1100 		/* if err or if this message says it wants a response */
1101 		if (err || (nlh->nlmsg_flags & NLM_F_ACK))
1102 			netlink_ack(skb, nlh, err);
1103 
1104 		nlh = nlmsg_next(nlh, &len);
1105 	}
1106 }
1107 
1108 /* Receive messages from netlink socket. */
1109 static void audit_receive(struct sk_buff  *skb)
1110 {
1111 	mutex_lock(&audit_cmd_mutex);
1112 	audit_receive_skb(skb);
1113 	mutex_unlock(&audit_cmd_mutex);
1114 }
1115 
1116 /* Run custom bind function on netlink socket group connect or bind requests. */
1117 static int audit_bind(struct net *net, int group)
1118 {
1119 	if (!capable(CAP_AUDIT_READ))
1120 		return -EPERM;
1121 
1122 	return 0;
1123 }
1124 
1125 static int __net_init audit_net_init(struct net *net)
1126 {
1127 	struct netlink_kernel_cfg cfg = {
1128 		.input	= audit_receive,
1129 		.bind	= audit_bind,
1130 		.flags	= NL_CFG_F_NONROOT_RECV,
1131 		.groups	= AUDIT_NLGRP_MAX,
1132 	};
1133 
1134 	struct audit_net *aunet = net_generic(net, audit_net_id);
1135 
1136 	aunet->nlsk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
1137 	if (aunet->nlsk == NULL) {
1138 		audit_panic("cannot initialize netlink socket in namespace");
1139 		return -ENOMEM;
1140 	}
1141 	aunet->nlsk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
1142 	return 0;
1143 }
1144 
1145 static void __net_exit audit_net_exit(struct net *net)
1146 {
1147 	struct audit_net *aunet = net_generic(net, audit_net_id);
1148 	struct sock *sock = aunet->nlsk;
1149 	if (sock == audit_sock) {
1150 		audit_pid = 0;
1151 		audit_sock = NULL;
1152 	}
1153 
1154 	RCU_INIT_POINTER(aunet->nlsk, NULL);
1155 	synchronize_net();
1156 	netlink_kernel_release(sock);
1157 }
1158 
1159 static struct pernet_operations audit_net_ops __net_initdata = {
1160 	.init = audit_net_init,
1161 	.exit = audit_net_exit,
1162 	.id = &audit_net_id,
1163 	.size = sizeof(struct audit_net),
1164 };
1165 
1166 /* Initialize audit support at boot time. */
1167 static int __init audit_init(void)
1168 {
1169 	int i;
1170 
1171 	if (audit_initialized == AUDIT_DISABLED)
1172 		return 0;
1173 
1174 	pr_info("initializing netlink subsys (%s)\n",
1175 		audit_default ? "enabled" : "disabled");
1176 	register_pernet_subsys(&audit_net_ops);
1177 
1178 	skb_queue_head_init(&audit_skb_queue);
1179 	skb_queue_head_init(&audit_skb_hold_queue);
1180 	audit_initialized = AUDIT_INITIALIZED;
1181 	audit_enabled = audit_default;
1182 	audit_ever_enabled |= !!audit_default;
1183 
1184 	audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized");
1185 
1186 	for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
1187 		INIT_LIST_HEAD(&audit_inode_hash[i]);
1188 
1189 	return 0;
1190 }
1191 __initcall(audit_init);
1192 
1193 /* Process kernel command-line parameter at boot time.  audit=0 or audit=1. */
1194 static int __init audit_enable(char *str)
1195 {
1196 	audit_default = !!simple_strtol(str, NULL, 0);
1197 	if (!audit_default)
1198 		audit_initialized = AUDIT_DISABLED;
1199 
1200 	pr_info("%s\n", audit_default ?
1201 		"enabled (after initialization)" : "disabled (until reboot)");
1202 
1203 	return 1;
1204 }
1205 __setup("audit=", audit_enable);
1206 
1207 /* Process kernel command-line parameter at boot time.
1208  * audit_backlog_limit=<n> */
1209 static int __init audit_backlog_limit_set(char *str)
1210 {
1211 	u32 audit_backlog_limit_arg;
1212 
1213 	pr_info("audit_backlog_limit: ");
1214 	if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
1215 		pr_cont("using default of %u, unable to parse %s\n",
1216 			audit_backlog_limit, str);
1217 		return 1;
1218 	}
1219 
1220 	audit_backlog_limit = audit_backlog_limit_arg;
1221 	pr_cont("%d\n", audit_backlog_limit);
1222 
1223 	return 1;
1224 }
1225 __setup("audit_backlog_limit=", audit_backlog_limit_set);
1226 
1227 static void audit_buffer_free(struct audit_buffer *ab)
1228 {
1229 	unsigned long flags;
1230 
1231 	if (!ab)
1232 		return;
1233 
1234 	kfree_skb(ab->skb);
1235 	spin_lock_irqsave(&audit_freelist_lock, flags);
1236 	if (audit_freelist_count > AUDIT_MAXFREE)
1237 		kfree(ab);
1238 	else {
1239 		audit_freelist_count++;
1240 		list_add(&ab->list, &audit_freelist);
1241 	}
1242 	spin_unlock_irqrestore(&audit_freelist_lock, flags);
1243 }
1244 
1245 static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx,
1246 						gfp_t gfp_mask, int type)
1247 {
1248 	unsigned long flags;
1249 	struct audit_buffer *ab = NULL;
1250 	struct nlmsghdr *nlh;
1251 
1252 	spin_lock_irqsave(&audit_freelist_lock, flags);
1253 	if (!list_empty(&audit_freelist)) {
1254 		ab = list_entry(audit_freelist.next,
1255 				struct audit_buffer, list);
1256 		list_del(&ab->list);
1257 		--audit_freelist_count;
1258 	}
1259 	spin_unlock_irqrestore(&audit_freelist_lock, flags);
1260 
1261 	if (!ab) {
1262 		ab = kmalloc(sizeof(*ab), gfp_mask);
1263 		if (!ab)
1264 			goto err;
1265 	}
1266 
1267 	ab->ctx = ctx;
1268 	ab->gfp_mask = gfp_mask;
1269 
1270 	ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
1271 	if (!ab->skb)
1272 		goto err;
1273 
1274 	nlh = nlmsg_put(ab->skb, 0, 0, type, 0, 0);
1275 	if (!nlh)
1276 		goto out_kfree_skb;
1277 
1278 	return ab;
1279 
1280 out_kfree_skb:
1281 	kfree_skb(ab->skb);
1282 	ab->skb = NULL;
1283 err:
1284 	audit_buffer_free(ab);
1285 	return NULL;
1286 }
1287 
1288 /**
1289  * audit_serial - compute a serial number for the audit record
1290  *
1291  * Compute a serial number for the audit record.  Audit records are
1292  * written to user-space as soon as they are generated, so a complete
1293  * audit record may be written in several pieces.  The timestamp of the
1294  * record and this serial number are used by the user-space tools to
1295  * determine which pieces belong to the same audit record.  The
1296  * (timestamp,serial) tuple is unique for each syscall and is live from
1297  * syscall entry to syscall exit.
1298  *
1299  * NOTE: Another possibility is to store the formatted records off the
1300  * audit context (for those records that have a context), and emit them
1301  * all at syscall exit.  However, this could delay the reporting of
1302  * significant errors until syscall exit (or never, if the system
1303  * halts).
1304  */
1305 unsigned int audit_serial(void)
1306 {
1307 	static atomic_t serial = ATOMIC_INIT(0);
1308 
1309 	return atomic_add_return(1, &serial);
1310 }
1311 
1312 static inline void audit_get_stamp(struct audit_context *ctx,
1313 				   struct timespec *t, unsigned int *serial)
1314 {
1315 	if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
1316 		*t = CURRENT_TIME;
1317 		*serial = audit_serial();
1318 	}
1319 }
1320 
1321 /*
1322  * Wait for auditd to drain the queue a little
1323  */
1324 static long wait_for_auditd(long sleep_time)
1325 {
1326 	DECLARE_WAITQUEUE(wait, current);
1327 	set_current_state(TASK_UNINTERRUPTIBLE);
1328 	add_wait_queue_exclusive(&audit_backlog_wait, &wait);
1329 
1330 	if (audit_backlog_limit &&
1331 	    skb_queue_len(&audit_skb_queue) > audit_backlog_limit)
1332 		sleep_time = schedule_timeout(sleep_time);
1333 
1334 	__set_current_state(TASK_RUNNING);
1335 	remove_wait_queue(&audit_backlog_wait, &wait);
1336 
1337 	return sleep_time;
1338 }
1339 
1340 /**
1341  * audit_log_start - obtain an audit buffer
1342  * @ctx: audit_context (may be NULL)
1343  * @gfp_mask: type of allocation
1344  * @type: audit message type
1345  *
1346  * Returns audit_buffer pointer on success or NULL on error.
1347  *
1348  * Obtain an audit buffer.  This routine does locking to obtain the
1349  * audit buffer, but then no locking is required for calls to
1350  * audit_log_*format.  If the task (ctx) is a task that is currently in a
1351  * syscall, then the syscall is marked as auditable and an audit record
1352  * will be written at syscall exit.  If there is no associated task, then
1353  * task context (ctx) should be NULL.
1354  */
1355 struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1356 				     int type)
1357 {
1358 	struct audit_buffer	*ab	= NULL;
1359 	struct timespec		t;
1360 	unsigned int		uninitialized_var(serial);
1361 	int reserve = 5; /* Allow atomic callers to go up to five
1362 			    entries over the normal backlog limit */
1363 	unsigned long timeout_start = jiffies;
1364 
1365 	if (audit_initialized != AUDIT_INITIALIZED)
1366 		return NULL;
1367 
1368 	if (unlikely(audit_filter_type(type)))
1369 		return NULL;
1370 
1371 	if (gfp_mask & __GFP_DIRECT_RECLAIM) {
1372 		if (audit_pid && audit_pid == current->tgid)
1373 			gfp_mask &= ~__GFP_DIRECT_RECLAIM;
1374 		else
1375 			reserve = 0;
1376 	}
1377 
1378 	while (audit_backlog_limit
1379 	       && skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) {
1380 		if (gfp_mask & __GFP_DIRECT_RECLAIM && audit_backlog_wait_time) {
1381 			long sleep_time;
1382 
1383 			sleep_time = timeout_start + audit_backlog_wait_time - jiffies;
1384 			if (sleep_time > 0) {
1385 				sleep_time = wait_for_auditd(sleep_time);
1386 				if (sleep_time > 0)
1387 					continue;
1388 			}
1389 		}
1390 		if (audit_rate_check() && printk_ratelimit())
1391 			pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
1392 				skb_queue_len(&audit_skb_queue),
1393 				audit_backlog_limit);
1394 		audit_log_lost("backlog limit exceeded");
1395 		audit_backlog_wait_time = 0;
1396 		wake_up(&audit_backlog_wait);
1397 		return NULL;
1398 	}
1399 
1400 	if (!reserve && !audit_backlog_wait_time)
1401 		audit_backlog_wait_time = audit_backlog_wait_time_master;
1402 
1403 	ab = audit_buffer_alloc(ctx, gfp_mask, type);
1404 	if (!ab) {
1405 		audit_log_lost("out of memory in audit_log_start");
1406 		return NULL;
1407 	}
1408 
1409 	audit_get_stamp(ab->ctx, &t, &serial);
1410 
1411 	audit_log_format(ab, "audit(%lu.%03lu:%u): ",
1412 			 t.tv_sec, t.tv_nsec/1000000, serial);
1413 	return ab;
1414 }
1415 
1416 /**
1417  * audit_expand - expand skb in the audit buffer
1418  * @ab: audit_buffer
1419  * @extra: space to add at tail of the skb
1420  *
1421  * Returns 0 (no space) on failed expansion, or available space if
1422  * successful.
1423  */
1424 static inline int audit_expand(struct audit_buffer *ab, int extra)
1425 {
1426 	struct sk_buff *skb = ab->skb;
1427 	int oldtail = skb_tailroom(skb);
1428 	int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1429 	int newtail = skb_tailroom(skb);
1430 
1431 	if (ret < 0) {
1432 		audit_log_lost("out of memory in audit_expand");
1433 		return 0;
1434 	}
1435 
1436 	skb->truesize += newtail - oldtail;
1437 	return newtail;
1438 }
1439 
1440 /*
1441  * Format an audit message into the audit buffer.  If there isn't enough
1442  * room in the audit buffer, more room will be allocated and vsnprint
1443  * will be called a second time.  Currently, we assume that a printk
1444  * can't format message larger than 1024 bytes, so we don't either.
1445  */
1446 static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1447 			      va_list args)
1448 {
1449 	int len, avail;
1450 	struct sk_buff *skb;
1451 	va_list args2;
1452 
1453 	if (!ab)
1454 		return;
1455 
1456 	BUG_ON(!ab->skb);
1457 	skb = ab->skb;
1458 	avail = skb_tailroom(skb);
1459 	if (avail == 0) {
1460 		avail = audit_expand(ab, AUDIT_BUFSIZ);
1461 		if (!avail)
1462 			goto out;
1463 	}
1464 	va_copy(args2, args);
1465 	len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1466 	if (len >= avail) {
1467 		/* The printk buffer is 1024 bytes long, so if we get
1468 		 * here and AUDIT_BUFSIZ is at least 1024, then we can
1469 		 * log everything that printk could have logged. */
1470 		avail = audit_expand(ab,
1471 			max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1472 		if (!avail)
1473 			goto out_va_end;
1474 		len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1475 	}
1476 	if (len > 0)
1477 		skb_put(skb, len);
1478 out_va_end:
1479 	va_end(args2);
1480 out:
1481 	return;
1482 }
1483 
1484 /**
1485  * audit_log_format - format a message into the audit buffer.
1486  * @ab: audit_buffer
1487  * @fmt: format string
1488  * @...: optional parameters matching @fmt string
1489  *
1490  * All the work is done in audit_log_vformat.
1491  */
1492 void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1493 {
1494 	va_list args;
1495 
1496 	if (!ab)
1497 		return;
1498 	va_start(args, fmt);
1499 	audit_log_vformat(ab, fmt, args);
1500 	va_end(args);
1501 }
1502 
1503 /**
1504  * audit_log_hex - convert a buffer to hex and append it to the audit skb
1505  * @ab: the audit_buffer
1506  * @buf: buffer to convert to hex
1507  * @len: length of @buf to be converted
1508  *
1509  * No return value; failure to expand is silently ignored.
1510  *
1511  * This function will take the passed buf and convert it into a string of
1512  * ascii hex digits. The new string is placed onto the skb.
1513  */
1514 void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
1515 		size_t len)
1516 {
1517 	int i, avail, new_len;
1518 	unsigned char *ptr;
1519 	struct sk_buff *skb;
1520 
1521 	if (!ab)
1522 		return;
1523 
1524 	BUG_ON(!ab->skb);
1525 	skb = ab->skb;
1526 	avail = skb_tailroom(skb);
1527 	new_len = len<<1;
1528 	if (new_len >= avail) {
1529 		/* Round the buffer request up to the next multiple */
1530 		new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1531 		avail = audit_expand(ab, new_len);
1532 		if (!avail)
1533 			return;
1534 	}
1535 
1536 	ptr = skb_tail_pointer(skb);
1537 	for (i = 0; i < len; i++)
1538 		ptr = hex_byte_pack_upper(ptr, buf[i]);
1539 	*ptr = 0;
1540 	skb_put(skb, len << 1); /* new string is twice the old string */
1541 }
1542 
1543 /*
1544  * Format a string of no more than slen characters into the audit buffer,
1545  * enclosed in quote marks.
1546  */
1547 void audit_log_n_string(struct audit_buffer *ab, const char *string,
1548 			size_t slen)
1549 {
1550 	int avail, new_len;
1551 	unsigned char *ptr;
1552 	struct sk_buff *skb;
1553 
1554 	if (!ab)
1555 		return;
1556 
1557 	BUG_ON(!ab->skb);
1558 	skb = ab->skb;
1559 	avail = skb_tailroom(skb);
1560 	new_len = slen + 3;	/* enclosing quotes + null terminator */
1561 	if (new_len > avail) {
1562 		avail = audit_expand(ab, new_len);
1563 		if (!avail)
1564 			return;
1565 	}
1566 	ptr = skb_tail_pointer(skb);
1567 	*ptr++ = '"';
1568 	memcpy(ptr, string, slen);
1569 	ptr += slen;
1570 	*ptr++ = '"';
1571 	*ptr = 0;
1572 	skb_put(skb, slen + 2);	/* don't include null terminator */
1573 }
1574 
1575 /**
1576  * audit_string_contains_control - does a string need to be logged in hex
1577  * @string: string to be checked
1578  * @len: max length of the string to check
1579  */
1580 bool audit_string_contains_control(const char *string, size_t len)
1581 {
1582 	const unsigned char *p;
1583 	for (p = string; p < (const unsigned char *)string + len; p++) {
1584 		if (*p == '"' || *p < 0x21 || *p > 0x7e)
1585 			return true;
1586 	}
1587 	return false;
1588 }
1589 
1590 /**
1591  * audit_log_n_untrustedstring - log a string that may contain random characters
1592  * @ab: audit_buffer
1593  * @len: length of string (not including trailing null)
1594  * @string: string to be logged
1595  *
1596  * This code will escape a string that is passed to it if the string
1597  * contains a control character, unprintable character, double quote mark,
1598  * or a space. Unescaped strings will start and end with a double quote mark.
1599  * Strings that are escaped are printed in hex (2 digits per char).
1600  *
1601  * The caller specifies the number of characters in the string to log, which may
1602  * or may not be the entire string.
1603  */
1604 void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
1605 				 size_t len)
1606 {
1607 	if (audit_string_contains_control(string, len))
1608 		audit_log_n_hex(ab, string, len);
1609 	else
1610 		audit_log_n_string(ab, string, len);
1611 }
1612 
1613 /**
1614  * audit_log_untrustedstring - log a string that may contain random characters
1615  * @ab: audit_buffer
1616  * @string: string to be logged
1617  *
1618  * Same as audit_log_n_untrustedstring(), except that strlen is used to
1619  * determine string length.
1620  */
1621 void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
1622 {
1623 	audit_log_n_untrustedstring(ab, string, strlen(string));
1624 }
1625 
1626 /* This is a helper-function to print the escaped d_path */
1627 void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
1628 		      const struct path *path)
1629 {
1630 	char *p, *pathname;
1631 
1632 	if (prefix)
1633 		audit_log_format(ab, "%s", prefix);
1634 
1635 	/* We will allow 11 spaces for ' (deleted)' to be appended */
1636 	pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
1637 	if (!pathname) {
1638 		audit_log_string(ab, "<no_memory>");
1639 		return;
1640 	}
1641 	p = d_path(path, pathname, PATH_MAX+11);
1642 	if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
1643 		/* FIXME: can we save some information here? */
1644 		audit_log_string(ab, "<too_long>");
1645 	} else
1646 		audit_log_untrustedstring(ab, p);
1647 	kfree(pathname);
1648 }
1649 
1650 void audit_log_session_info(struct audit_buffer *ab)
1651 {
1652 	unsigned int sessionid = audit_get_sessionid(current);
1653 	uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
1654 
1655 	audit_log_format(ab, " auid=%u ses=%u", auid, sessionid);
1656 }
1657 
1658 void audit_log_key(struct audit_buffer *ab, char *key)
1659 {
1660 	audit_log_format(ab, " key=");
1661 	if (key)
1662 		audit_log_untrustedstring(ab, key);
1663 	else
1664 		audit_log_format(ab, "(null)");
1665 }
1666 
1667 void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap)
1668 {
1669 	int i;
1670 
1671 	audit_log_format(ab, " %s=", prefix);
1672 	CAP_FOR_EACH_U32(i) {
1673 		audit_log_format(ab, "%08x",
1674 				 cap->cap[CAP_LAST_U32 - i]);
1675 	}
1676 }
1677 
1678 static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
1679 {
1680 	kernel_cap_t *perm = &name->fcap.permitted;
1681 	kernel_cap_t *inh = &name->fcap.inheritable;
1682 	int log = 0;
1683 
1684 	if (!cap_isclear(*perm)) {
1685 		audit_log_cap(ab, "cap_fp", perm);
1686 		log = 1;
1687 	}
1688 	if (!cap_isclear(*inh)) {
1689 		audit_log_cap(ab, "cap_fi", inh);
1690 		log = 1;
1691 	}
1692 
1693 	if (log)
1694 		audit_log_format(ab, " cap_fe=%d cap_fver=%x",
1695 				 name->fcap.fE, name->fcap_ver);
1696 }
1697 
1698 static inline int audit_copy_fcaps(struct audit_names *name,
1699 				   const struct dentry *dentry)
1700 {
1701 	struct cpu_vfs_cap_data caps;
1702 	int rc;
1703 
1704 	if (!dentry)
1705 		return 0;
1706 
1707 	rc = get_vfs_caps_from_disk(dentry, &caps);
1708 	if (rc)
1709 		return rc;
1710 
1711 	name->fcap.permitted = caps.permitted;
1712 	name->fcap.inheritable = caps.inheritable;
1713 	name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
1714 	name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >>
1715 				VFS_CAP_REVISION_SHIFT;
1716 
1717 	return 0;
1718 }
1719 
1720 /* Copy inode data into an audit_names. */
1721 void audit_copy_inode(struct audit_names *name, const struct dentry *dentry,
1722 		      struct inode *inode)
1723 {
1724 	name->ino   = inode->i_ino;
1725 	name->dev   = inode->i_sb->s_dev;
1726 	name->mode  = inode->i_mode;
1727 	name->uid   = inode->i_uid;
1728 	name->gid   = inode->i_gid;
1729 	name->rdev  = inode->i_rdev;
1730 	security_inode_getsecid(inode, &name->osid);
1731 	audit_copy_fcaps(name, dentry);
1732 }
1733 
1734 /**
1735  * audit_log_name - produce AUDIT_PATH record from struct audit_names
1736  * @context: audit_context for the task
1737  * @n: audit_names structure with reportable details
1738  * @path: optional path to report instead of audit_names->name
1739  * @record_num: record number to report when handling a list of names
1740  * @call_panic: optional pointer to int that will be updated if secid fails
1741  */
1742 void audit_log_name(struct audit_context *context, struct audit_names *n,
1743 		    struct path *path, int record_num, int *call_panic)
1744 {
1745 	struct audit_buffer *ab;
1746 	ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH);
1747 	if (!ab)
1748 		return;
1749 
1750 	audit_log_format(ab, "item=%d", record_num);
1751 
1752 	if (path)
1753 		audit_log_d_path(ab, " name=", path);
1754 	else if (n->name) {
1755 		switch (n->name_len) {
1756 		case AUDIT_NAME_FULL:
1757 			/* log the full path */
1758 			audit_log_format(ab, " name=");
1759 			audit_log_untrustedstring(ab, n->name->name);
1760 			break;
1761 		case 0:
1762 			/* name was specified as a relative path and the
1763 			 * directory component is the cwd */
1764 			audit_log_d_path(ab, " name=", &context->pwd);
1765 			break;
1766 		default:
1767 			/* log the name's directory component */
1768 			audit_log_format(ab, " name=");
1769 			audit_log_n_untrustedstring(ab, n->name->name,
1770 						    n->name_len);
1771 		}
1772 	} else
1773 		audit_log_format(ab, " name=(null)");
1774 
1775 	if (n->ino != AUDIT_INO_UNSET)
1776 		audit_log_format(ab, " inode=%lu"
1777 				 " dev=%02x:%02x mode=%#ho"
1778 				 " ouid=%u ogid=%u rdev=%02x:%02x",
1779 				 n->ino,
1780 				 MAJOR(n->dev),
1781 				 MINOR(n->dev),
1782 				 n->mode,
1783 				 from_kuid(&init_user_ns, n->uid),
1784 				 from_kgid(&init_user_ns, n->gid),
1785 				 MAJOR(n->rdev),
1786 				 MINOR(n->rdev));
1787 	if (n->osid != 0) {
1788 		char *ctx = NULL;
1789 		u32 len;
1790 		if (security_secid_to_secctx(
1791 			n->osid, &ctx, &len)) {
1792 			audit_log_format(ab, " osid=%u", n->osid);
1793 			if (call_panic)
1794 				*call_panic = 2;
1795 		} else {
1796 			audit_log_format(ab, " obj=%s", ctx);
1797 			security_release_secctx(ctx, len);
1798 		}
1799 	}
1800 
1801 	/* log the audit_names record type */
1802 	audit_log_format(ab, " nametype=");
1803 	switch(n->type) {
1804 	case AUDIT_TYPE_NORMAL:
1805 		audit_log_format(ab, "NORMAL");
1806 		break;
1807 	case AUDIT_TYPE_PARENT:
1808 		audit_log_format(ab, "PARENT");
1809 		break;
1810 	case AUDIT_TYPE_CHILD_DELETE:
1811 		audit_log_format(ab, "DELETE");
1812 		break;
1813 	case AUDIT_TYPE_CHILD_CREATE:
1814 		audit_log_format(ab, "CREATE");
1815 		break;
1816 	default:
1817 		audit_log_format(ab, "UNKNOWN");
1818 		break;
1819 	}
1820 
1821 	audit_log_fcaps(ab, n);
1822 	audit_log_end(ab);
1823 }
1824 
1825 int audit_log_task_context(struct audit_buffer *ab)
1826 {
1827 	char *ctx = NULL;
1828 	unsigned len;
1829 	int error;
1830 	u32 sid;
1831 
1832 	security_task_getsecid(current, &sid);
1833 	if (!sid)
1834 		return 0;
1835 
1836 	error = security_secid_to_secctx(sid, &ctx, &len);
1837 	if (error) {
1838 		if (error != -EINVAL)
1839 			goto error_path;
1840 		return 0;
1841 	}
1842 
1843 	audit_log_format(ab, " subj=%s", ctx);
1844 	security_release_secctx(ctx, len);
1845 	return 0;
1846 
1847 error_path:
1848 	audit_panic("error in audit_log_task_context");
1849 	return error;
1850 }
1851 EXPORT_SYMBOL(audit_log_task_context);
1852 
1853 void audit_log_d_path_exe(struct audit_buffer *ab,
1854 			  struct mm_struct *mm)
1855 {
1856 	struct file *exe_file;
1857 
1858 	if (!mm)
1859 		goto out_null;
1860 
1861 	exe_file = get_mm_exe_file(mm);
1862 	if (!exe_file)
1863 		goto out_null;
1864 
1865 	audit_log_d_path(ab, " exe=", &exe_file->f_path);
1866 	fput(exe_file);
1867 	return;
1868 out_null:
1869 	audit_log_format(ab, " exe=(null)");
1870 }
1871 
1872 void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
1873 {
1874 	const struct cred *cred;
1875 	char comm[sizeof(tsk->comm)];
1876 	char *tty;
1877 
1878 	if (!ab)
1879 		return;
1880 
1881 	/* tsk == current */
1882 	cred = current_cred();
1883 
1884 	spin_lock_irq(&tsk->sighand->siglock);
1885 	if (tsk->signal && tsk->signal->tty && tsk->signal->tty->name)
1886 		tty = tsk->signal->tty->name;
1887 	else
1888 		tty = "(none)";
1889 	spin_unlock_irq(&tsk->sighand->siglock);
1890 
1891 	audit_log_format(ab,
1892 			 " ppid=%d pid=%d auid=%u uid=%u gid=%u"
1893 			 " euid=%u suid=%u fsuid=%u"
1894 			 " egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
1895 			 task_ppid_nr(tsk),
1896 			 task_pid_nr(tsk),
1897 			 from_kuid(&init_user_ns, audit_get_loginuid(tsk)),
1898 			 from_kuid(&init_user_ns, cred->uid),
1899 			 from_kgid(&init_user_ns, cred->gid),
1900 			 from_kuid(&init_user_ns, cred->euid),
1901 			 from_kuid(&init_user_ns, cred->suid),
1902 			 from_kuid(&init_user_ns, cred->fsuid),
1903 			 from_kgid(&init_user_ns, cred->egid),
1904 			 from_kgid(&init_user_ns, cred->sgid),
1905 			 from_kgid(&init_user_ns, cred->fsgid),
1906 			 tty, audit_get_sessionid(tsk));
1907 
1908 	audit_log_format(ab, " comm=");
1909 	audit_log_untrustedstring(ab, get_task_comm(comm, tsk));
1910 
1911 	audit_log_d_path_exe(ab, tsk->mm);
1912 	audit_log_task_context(ab);
1913 }
1914 EXPORT_SYMBOL(audit_log_task_info);
1915 
1916 /**
1917  * audit_log_link_denied - report a link restriction denial
1918  * @operation: specific link operation
1919  * @link: the path that triggered the restriction
1920  */
1921 void audit_log_link_denied(const char *operation, struct path *link)
1922 {
1923 	struct audit_buffer *ab;
1924 	struct audit_names *name;
1925 
1926 	name = kzalloc(sizeof(*name), GFP_NOFS);
1927 	if (!name)
1928 		return;
1929 
1930 	/* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */
1931 	ab = audit_log_start(current->audit_context, GFP_KERNEL,
1932 			     AUDIT_ANOM_LINK);
1933 	if (!ab)
1934 		goto out;
1935 	audit_log_format(ab, "op=%s", operation);
1936 	audit_log_task_info(ab, current);
1937 	audit_log_format(ab, " res=0");
1938 	audit_log_end(ab);
1939 
1940 	/* Generate AUDIT_PATH record with object. */
1941 	name->type = AUDIT_TYPE_NORMAL;
1942 	audit_copy_inode(name, link->dentry, d_backing_inode(link->dentry));
1943 	audit_log_name(current->audit_context, name, link, 0, NULL);
1944 out:
1945 	kfree(name);
1946 }
1947 
1948 /**
1949  * audit_log_end - end one audit record
1950  * @ab: the audit_buffer
1951  *
1952  * netlink_unicast() cannot be called inside an irq context because it blocks
1953  * (last arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed
1954  * on a queue and a tasklet is scheduled to remove them from the queue outside
1955  * the irq context.  May be called in any context.
1956  */
1957 void audit_log_end(struct audit_buffer *ab)
1958 {
1959 	if (!ab)
1960 		return;
1961 	if (!audit_rate_check()) {
1962 		audit_log_lost("rate limit exceeded");
1963 	} else {
1964 		struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
1965 
1966 		nlh->nlmsg_len = ab->skb->len;
1967 		kauditd_send_multicast_skb(ab->skb, ab->gfp_mask);
1968 
1969 		/*
1970 		 * The original kaudit unicast socket sends up messages with
1971 		 * nlmsg_len set to the payload length rather than the entire
1972 		 * message length.  This breaks the standard set by netlink.
1973 		 * The existing auditd daemon assumes this breakage.  Fixing
1974 		 * this would require co-ordinating a change in the established
1975 		 * protocol between the kaudit kernel subsystem and the auditd
1976 		 * userspace code.
1977 		 */
1978 		nlh->nlmsg_len -= NLMSG_HDRLEN;
1979 
1980 		if (audit_pid) {
1981 			skb_queue_tail(&audit_skb_queue, ab->skb);
1982 			wake_up_interruptible(&kauditd_wait);
1983 		} else {
1984 			audit_printk_skb(ab->skb);
1985 		}
1986 		ab->skb = NULL;
1987 	}
1988 	audit_buffer_free(ab);
1989 }
1990 
1991 /**
1992  * audit_log - Log an audit record
1993  * @ctx: audit context
1994  * @gfp_mask: type of allocation
1995  * @type: audit message type
1996  * @fmt: format string to use
1997  * @...: variable parameters matching the format string
1998  *
1999  * This is a convenience function that calls audit_log_start,
2000  * audit_log_vformat, and audit_log_end.  It may be called
2001  * in any context.
2002  */
2003 void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
2004 	       const char *fmt, ...)
2005 {
2006 	struct audit_buffer *ab;
2007 	va_list args;
2008 
2009 	ab = audit_log_start(ctx, gfp_mask, type);
2010 	if (ab) {
2011 		va_start(args, fmt);
2012 		audit_log_vformat(ab, fmt, args);
2013 		va_end(args);
2014 		audit_log_end(ab);
2015 	}
2016 }
2017 
2018 #ifdef CONFIG_SECURITY
2019 /**
2020  * audit_log_secctx - Converts and logs SELinux context
2021  * @ab: audit_buffer
2022  * @secid: security number
2023  *
2024  * This is a helper function that calls security_secid_to_secctx to convert
2025  * secid to secctx and then adds the (converted) SELinux context to the audit
2026  * log by calling audit_log_format, thus also preventing leak of internal secid
2027  * to userspace. If secid cannot be converted audit_panic is called.
2028  */
2029 void audit_log_secctx(struct audit_buffer *ab, u32 secid)
2030 {
2031 	u32 len;
2032 	char *secctx;
2033 
2034 	if (security_secid_to_secctx(secid, &secctx, &len)) {
2035 		audit_panic("Cannot convert secid to context");
2036 	} else {
2037 		audit_log_format(ab, " obj=%s", secctx);
2038 		security_release_secctx(secctx, len);
2039 	}
2040 }
2041 EXPORT_SYMBOL(audit_log_secctx);
2042 #endif
2043 
2044 EXPORT_SYMBOL(audit_log_start);
2045 EXPORT_SYMBOL(audit_log_end);
2046 EXPORT_SYMBOL(audit_log_format);
2047 EXPORT_SYMBOL(audit_log);
2048