path: root/kernel/audit.c (plain)
blob: 3461a3d874feda801cef8af5d3b85a54e17187b7

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/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 = AUDIT_OFF;
83	u32 audit_ever_enabled = !!AUDIT_OFF;
84
85	EXPORT_SYMBOL_GPL(audit_enabled);
86
87	/* Default state when kernel boots without any parameters. */
88	static u32 audit_default = AUDIT_OFF;
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_master = AUDIT_BACKLOG_WAIT_TIME;
111	static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
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	static 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_master, timeout);
342	}
343
344	static int audit_set_enabled(u32 state)
345	{
346	int rc;
347	if (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	int attempts = 0;
409	#define AUDITD_RETRIES 5
410
411	restart:
412	/* take a reference in case we can't send it and we want to hold it */
413	skb_get(skb);
414	err = netlink_unicast(audit_sock, skb, audit_nlk_portid, 0);
415	if (err < 0) {
416	pr_err("netlink_unicast sending to audit_pid=%d returned error: %d\n",
417	audit_pid, err);
418	if (audit_pid) {
419	if (err == -ECONNREFUSED || err == -EPERM
420	|| ++attempts >= AUDITD_RETRIES) {
421	char s[32];
422
423	snprintf(s, sizeof(s), "audit_pid=%d reset", audit_pid);
424	audit_log_lost(s);
425	audit_pid = 0;
426	audit_sock = NULL;
427	} else {
428	pr_warn("re-scheduling(#%d) write to audit_pid=%d\n",
429	attempts, audit_pid);
430	set_current_state(TASK_INTERRUPTIBLE);
431	schedule();
432	goto restart;
433	}
434	}
435	/* we might get lucky and get this in the next auditd */
436	audit_hold_skb(skb);
437	} else
438	/* drop the extra reference if sent ok */
439	consume_skb(skb);
440	}
441
442	/*
443	* kauditd_send_multicast_skb - send the skb to multicast userspace listeners
444	*
445	* This function doesn't consume an skb as might be expected since it has to
446	* copy it anyways.
447	*/
448	static void kauditd_send_multicast_skb(struct sk_buff *skb, gfp_t gfp_mask)
449	{
450	struct sk_buff *copy;
451	struct audit_net *aunet = net_generic(&init_net, audit_net_id);
452	struct sock *sock = aunet->nlsk;
453
454	if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
455	return;
456
457	/*
458	* The seemingly wasteful skb_copy() rather than bumping the refcount
459	* using skb_get() is necessary because non-standard mods are made to
460	* the skb by the original kaudit unicast socket send routine. The
461	* existing auditd daemon assumes this breakage. Fixing this would
462	* require co-ordinating a change in the established protocol between
463	* the kaudit kernel subsystem and the auditd userspace code. There is
464	* no reason for new multicast clients to continue with this
465	* non-compliance.
466	*/
467	copy = skb_copy(skb, gfp_mask);
468	if (!copy)
469	return;
470
471	nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, gfp_mask);
472	}
473
474	/*
475	* flush_hold_queue - empty the hold queue if auditd appears
476	*
477	* If auditd just started, drain the queue of messages already
478	* sent to syslog/printk. Remember loss here is ok. We already
479	* called audit_log_lost() if it didn't go out normally. so the
480	* race between the skb_dequeue and the next check for audit_pid
481	* doesn't matter.
482	*
483	* If you ever find kauditd to be too slow we can get a perf win
484	* by doing our own locking and keeping better track if there
485	* are messages in this queue. I don't see the need now, but
486	* in 5 years when I want to play with this again I'll see this
487	* note and still have no friggin idea what i'm thinking today.
488	*/
489	static void flush_hold_queue(void)
490	{
491	struct sk_buff *skb;
492
493	if (!audit_default || !audit_pid)
494	return;
495
496	skb = skb_dequeue(&audit_skb_hold_queue);
497	if (likely(!skb))
498	return;
499
500	while (skb && audit_pid) {
501	kauditd_send_skb(skb);
502	skb = skb_dequeue(&audit_skb_hold_queue);
503	}
504
505	/*
506	* if auditd just disappeared but we
507	* dequeued an skb we need to drop ref
508	*/
509	consume_skb(skb);
510	}
511
512	static int kauditd_thread(void *dummy)
513	{
514	set_freezable();
515	while (!kthread_should_stop()) {
516	struct sk_buff *skb;
517
518	flush_hold_queue();
519
520	skb = skb_dequeue(&audit_skb_queue);
521
522	if (skb) {
523	if (!audit_backlog_limit ||
524	(skb_queue_len(&audit_skb_queue) <= audit_backlog_limit))
525	wake_up(&audit_backlog_wait);
526	if (audit_pid)
527	kauditd_send_skb(skb);
528	else
529	audit_printk_skb(skb);
530	continue;
531	}
532
533	wait_event_freezable(kauditd_wait, skb_queue_len(&audit_skb_queue));
534	}
535	return 0;
536	}
537
538	int audit_send_list(void *_dest)
539	{
540	struct audit_netlink_list *dest = _dest;
541	struct sk_buff *skb;
542	struct net *net = dest->net;
543	struct audit_net *aunet = net_generic(net, audit_net_id);
544
545	/* wait for parent to finish and send an ACK */
546	mutex_lock(&audit_cmd_mutex);
547	mutex_unlock(&audit_cmd_mutex);
548
549	while ((skb = __skb_dequeue(&dest->q)) != NULL)
550	netlink_unicast(aunet->nlsk, skb, dest->portid, 0);
551
552	put_net(net);
553	kfree(dest);
554
555	return 0;
556	}
557
558	struct sk_buff *audit_make_reply(__u32 portid, int seq, int type, int done,
559	int multi, const void *payload, int size)
560	{
561	struct sk_buff *skb;
562	struct nlmsghdr *nlh;
563	void *data;
564	int flags = multi ? NLM_F_MULTI : 0;
565	int t = done ? NLMSG_DONE : type;
566
567	skb = nlmsg_new(size, GFP_KERNEL);
568	if (!skb)
569	return NULL;
570
571	nlh = nlmsg_put(skb, portid, seq, t, size, flags);
572	if (!nlh)
573	goto out_kfree_skb;
574	data = nlmsg_data(nlh);
575	memcpy(data, payload, size);
576	return skb;
577
578	out_kfree_skb:
579	kfree_skb(skb);
580	return NULL;
581	}
582
583	static int audit_send_reply_thread(void *arg)
584	{
585	struct audit_reply *reply = (struct audit_reply *)arg;
586	struct net *net = reply->net;
587	struct audit_net *aunet = net_generic(net, audit_net_id);
588
589	mutex_lock(&audit_cmd_mutex);
590	mutex_unlock(&audit_cmd_mutex);
591
592	/* Ignore failure. It'll only happen if the sender goes away,
593	because our timeout is set to infinite. */
594	netlink_unicast(aunet->nlsk , reply->skb, reply->portid, 0);
595	put_net(net);
596	kfree(reply);
597	return 0;
598	}
599	/**
600	* audit_send_reply - send an audit reply message via netlink
601	* @request_skb: skb of request we are replying to (used to target the reply)
602	* @seq: sequence number
603	* @type: audit message type
604	* @done: done (last) flag
605	* @multi: multi-part message flag
606	* @payload: payload data
607	* @size: payload size
608	*
609	* Allocates an skb, builds the netlink message, and sends it to the port id.
610	* No failure notifications.
611	*/
612	static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
613	int multi, const void *payload, int size)
614	{
615	u32 portid = NETLINK_CB(request_skb).portid;
616	struct net *net = sock_net(NETLINK_CB(request_skb).sk);
617	struct sk_buff *skb;
618	struct task_struct *tsk;
619	struct audit_reply *reply = kmalloc(sizeof(struct audit_reply),
620	GFP_KERNEL);
621
622	if (!reply)
623	return;
624
625	skb = audit_make_reply(portid, seq, type, done, multi, payload, size);
626	if (!skb)
627	goto out;
628
629	reply->net = get_net(net);
630	reply->portid = portid;
631	reply->skb = skb;
632
633	tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
634	if (!IS_ERR(tsk))
635	return;
636	kfree_skb(skb);
637	out:
638	kfree(reply);
639	}
640
641	/*
642	* Check for appropriate CAP_AUDIT_ capabilities on incoming audit
643	* control messages.
644	*/
645	static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
646	{
647	int err = 0;
648
649	/* Only support initial user namespace for now. */
650	/*
651	* We return ECONNREFUSED because it tricks userspace into thinking
652	* that audit was not configured into the kernel. Lots of users
653	* configure their PAM stack (because that's what the distro does)
654	* to reject login if unable to send messages to audit. If we return
655	* ECONNREFUSED the PAM stack thinks the kernel does not have audit
656	* configured in and will let login proceed. If we return EPERM
657	* userspace will reject all logins. This should be removed when we
658	* support non init namespaces!!
659	*/
660	if (current_user_ns() != &init_user_ns)
661	return -ECONNREFUSED;
662
663	switch (msg_type) {
664	case AUDIT_LIST:
665	case AUDIT_ADD:
666	case AUDIT_DEL:
667	return -EOPNOTSUPP;
668	case AUDIT_GET:
669	case AUDIT_SET:
670	case AUDIT_GET_FEATURE:
671	case AUDIT_SET_FEATURE:
672	case AUDIT_LIST_RULES:
673	case AUDIT_ADD_RULE:
674	case AUDIT_DEL_RULE:
675	case AUDIT_SIGNAL_INFO:
676	case AUDIT_TTY_GET:
677	case AUDIT_TTY_SET:
678	case AUDIT_TRIM:
679	case AUDIT_MAKE_EQUIV:
680	/* Only support auditd and auditctl in initial pid namespace
681	* for now. */
682	if (task_active_pid_ns(current) != &init_pid_ns)
683	return -EPERM;
684
685	if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
686	err = -EPERM;
687	break;
688	case AUDIT_USER:
689	case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
690	case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
691	if (!netlink_capable(skb, CAP_AUDIT_WRITE))
692	err = -EPERM;
693	break;
694	default: /* bad msg */
695	err = -EINVAL;
696	}
697
698	return err;
699	}
700
701	static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
702	{
703	uid_t uid = from_kuid(&init_user_ns, current_uid());
704	pid_t pid = task_tgid_nr(current);
705
706	if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
707	*ab = NULL;
708	return;
709	}
710
711	*ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
712	if (unlikely(!*ab))
713	return;
714	audit_log_format(*ab, "pid=%d uid=%u", pid, uid);
715	audit_log_session_info(*ab);
716	audit_log_task_context(*ab);
717	}
718
719	int is_audit_feature_set(int i)
720	{
721	return af.features & AUDIT_FEATURE_TO_MASK(i);
722	}
723
724
725	static int audit_get_feature(struct sk_buff *skb)
726	{
727	u32 seq;
728
729	seq = nlmsg_hdr(skb)->nlmsg_seq;
730
731	audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af));
732
733	return 0;
734	}
735
736	static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
737	u32 old_lock, u32 new_lock, int res)
738	{
739	struct audit_buffer *ab;
740
741	if (audit_enabled == AUDIT_OFF)
742	return;
743
744	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_FEATURE_CHANGE);
745	if (!ab)
746	return;
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_replace(pid_t pid)
813	{
814	struct sk_buff *skb = audit_make_reply(0, 0, AUDIT_REPLACE, 0, 0,
815	&pid, sizeof(pid));
816
817	if (!skb)
818	return -ENOMEM;
819	return netlink_unicast(audit_sock, skb, audit_nlk_portid, 0);
820	}
821
822	static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
823	{
824	u32 seq;
825	void *data;
826	int err;
827	struct audit_buffer *ab;
828	u16 msg_type = nlh->nlmsg_type;
829	struct audit_sig_info *sig_data;
830	char *ctx = NULL;
831	u32 len;
832
833	err = audit_netlink_ok(skb, msg_type);
834	if (err)
835	return err;
836
837	/* As soon as there's any sign of userspace auditd,
838	* start kauditd to talk to it */
839	if (!kauditd_task) {
840	kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
841	if (IS_ERR(kauditd_task)) {
842	err = PTR_ERR(kauditd_task);
843	kauditd_task = NULL;
844	return err;
845	}
846	}
847	seq = nlh->nlmsg_seq;
848	data = nlmsg_data(nlh);
849
850	switch (msg_type) {
851	case AUDIT_GET: {
852	struct audit_status s;
853	memset(&s, 0, sizeof(s));
854	s.enabled = audit_enabled;
855	s.failure = audit_failure;
856	s.pid = audit_pid;
857	s.rate_limit = audit_rate_limit;
858	s.backlog_limit = audit_backlog_limit;
859	s.lost = atomic_read(&audit_lost);
860	s.backlog = skb_queue_len(&audit_skb_queue);
861	s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL;
862	s.backlog_wait_time = audit_backlog_wait_time_master;
863	audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
864	break;
865	}
866	case AUDIT_SET: {
867	struct audit_status s;
868	memset(&s, 0, sizeof(s));
869	/* guard against past and future API changes */
870	memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
871	if (s.mask & AUDIT_STATUS_ENABLED) {
872	err = audit_set_enabled(s.enabled);
873	if (err < 0)
874	return err;
875	}
876	if (s.mask & AUDIT_STATUS_FAILURE) {
877	err = audit_set_failure(s.failure);
878	if (err < 0)
879	return err;
880	}
881	if (s.mask & AUDIT_STATUS_PID) {
882	/* NOTE: we are using task_tgid_vnr() below because
883	* the s.pid value is relative to the namespace
884	* of the caller; at present this doesn't matter
885	* much since you can really only run auditd
886	* from the initial pid namespace, but something
887	* to keep in mind if this changes */
888	int new_pid = s.pid;
889	pid_t requesting_pid = task_tgid_vnr(current);
890
891	if ((!new_pid) && (requesting_pid != audit_pid)) {
892	audit_log_config_change("audit_pid", new_pid, audit_pid, 0);
893	return -EACCES;
894	}
895	if (audit_pid && new_pid &&
896	audit_replace(requesting_pid) != -ECONNREFUSED) {
897	audit_log_config_change("audit_pid", new_pid, audit_pid, 0);
898	return -EEXIST;
899	}
900	if (audit_enabled != AUDIT_OFF)
901	audit_log_config_change("audit_pid", new_pid, audit_pid, 1);
902	audit_pid = new_pid;
903	audit_nlk_portid = NETLINK_CB(skb).portid;
904	audit_sock = skb->sk;
905	}
906	if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
907	err = audit_set_rate_limit(s.rate_limit);
908	if (err < 0)
909	return err;
910	}
911	if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
912	err = audit_set_backlog_limit(s.backlog_limit);
913	if (err < 0)
914	return err;
915	}
916	if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
917	if (sizeof(s) > (size_t)nlh->nlmsg_len)
918	return -EINVAL;
919	if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
920	return -EINVAL;
921	err = audit_set_backlog_wait_time(s.backlog_wait_time);
922	if (err < 0)
923	return err;
924	}
925	break;
926	}
927	case AUDIT_GET_FEATURE:
928	err = audit_get_feature(skb);
929	if (err)
930	return err;
931	break;
932	case AUDIT_SET_FEATURE:
933	err = audit_set_feature(skb);
934	if (err)
935	return err;
936	break;
937	case AUDIT_USER:
938	case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
939	case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
940	if (!audit_enabled && msg_type != AUDIT_USER_AVC)
941	return 0;
942
943	err = audit_filter(msg_type, AUDIT_FILTER_USER);
944	if (err == 1) { /* match or error */
945	err = 0;
946	if (msg_type == AUDIT_USER_TTY) {
947	err = tty_audit_push();
948	if (err)
949	break;
950	}
951	mutex_unlock(&audit_cmd_mutex);
952	audit_log_common_recv_msg(&ab, msg_type);
953	if (msg_type != AUDIT_USER_TTY)
954	audit_log_format(ab, " msg='%.*s'",
955	AUDIT_MESSAGE_TEXT_MAX,
956	(char *)data);
957	else {
958	int size;
959
960	audit_log_format(ab, " data=");
961	size = nlmsg_len(nlh);
962	if (size > 0 &&
963	((unsigned char *)data)[size - 1] == '\0')
964	size--;
965	audit_log_n_untrustedstring(ab, data, size);
966	}
967	audit_set_portid(ab, NETLINK_CB(skb).portid);
968	audit_log_end(ab);
969	mutex_lock(&audit_cmd_mutex);
970	}
971	break;
972	case AUDIT_ADD_RULE:
973	case AUDIT_DEL_RULE:
974	if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
975	return -EINVAL;
976	if (audit_enabled == AUDIT_LOCKED) {
977	audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
978	audit_log_format(ab, " audit_enabled=%d res=0", audit_enabled);
979	audit_log_end(ab);
980	return -EPERM;
981	}
982	err = audit_rule_change(msg_type, NETLINK_CB(skb).portid,
983	seq, data, nlmsg_len(nlh));
984	break;
985	case AUDIT_LIST_RULES:
986	err = audit_list_rules_send(skb, seq);
987	break;
988	case AUDIT_TRIM:
989	audit_trim_trees();
990	audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
991	audit_log_format(ab, " op=trim res=1");
992	audit_log_end(ab);
993	break;
994	case AUDIT_MAKE_EQUIV: {
995	void *bufp = data;
996	u32 sizes[2];
997	size_t msglen = nlmsg_len(nlh);
998	char *old, *new;
999
1000	err = -EINVAL;
1001	if (msglen < 2 * sizeof(u32))
1002	break;
1003	memcpy(sizes, bufp, 2 * sizeof(u32));
1004	bufp += 2 * sizeof(u32);
1005	msglen -= 2 * sizeof(u32);
1006	old = audit_unpack_string(&bufp, &msglen, sizes[0]);
1007	if (IS_ERR(old)) {
1008	err = PTR_ERR(old);
1009	break;
1010	}
1011	new = audit_unpack_string(&bufp, &msglen, sizes[1]);
1012	if (IS_ERR(new)) {
1013	err = PTR_ERR(new);
1014	kfree(old);
1015	break;
1016	}
1017	/* OK, here comes... */
1018	err = audit_tag_tree(old, new);
1019
1020	audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1021
1022	audit_log_format(ab, " op=make_equiv old=");
1023	audit_log_untrustedstring(ab, old);
1024	audit_log_format(ab, " new=");
1025	audit_log_untrustedstring(ab, new);
1026	audit_log_format(ab, " res=%d", !err);
1027	audit_log_end(ab);
1028	kfree(old);
1029	kfree(new);
1030	break;
1031	}
1032	case AUDIT_SIGNAL_INFO:
1033	len = 0;
1034	if (audit_sig_sid) {
1035	err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
1036	if (err)
1037	return err;
1038	}
1039	sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
1040	if (!sig_data) {
1041	if (audit_sig_sid)
1042	security_release_secctx(ctx, len);
1043	return -ENOMEM;
1044	}
1045	sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
1046	sig_data->pid = audit_sig_pid;
1047	if (audit_sig_sid) {
1048	memcpy(sig_data->ctx, ctx, len);
1049	security_release_secctx(ctx, len);
1050	}
1051	audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
1052	sig_data, sizeof(*sig_data) + len);
1053	kfree(sig_data);
1054	break;
1055	case AUDIT_TTY_GET: {
1056	struct audit_tty_status s;
1057	unsigned int t;
1058
1059	t = READ_ONCE(current->signal->audit_tty);
1060	s.enabled = t & AUDIT_TTY_ENABLE;
1061	s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1062
1063	audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
1064	break;
1065	}
1066	case AUDIT_TTY_SET: {
1067	struct audit_tty_status s, old;
1068	struct audit_buffer *ab;
1069	unsigned int t;
1070
1071	memset(&s, 0, sizeof(s));
1072	/* guard against past and future API changes */
1073	memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
1074	/* check if new data is valid */
1075	if ((s.enabled != 0 && s.enabled != 1) ||
1076	(s.log_passwd != 0 && s.log_passwd != 1))
1077	err = -EINVAL;
1078
1079	if (err)
1080	t = READ_ONCE(current->signal->audit_tty);
1081	else {
1082	t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD);
1083	t = xchg(&current->signal->audit_tty, t);
1084	}
1085	old.enabled = t & AUDIT_TTY_ENABLE;
1086	old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1087
1088	audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1089	audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
1090	" old-log_passwd=%d new-log_passwd=%d res=%d",
1091	old.enabled, s.enabled, old.log_passwd,
1092	s.log_passwd, !err);
1093	audit_log_end(ab);
1094	break;
1095	}
1096	default:
1097	err = -EINVAL;
1098	break;
1099	}
1100
1101	return err < 0 ? err : 0;
1102	}
1103
1104	/*
1105	* Get message from skb. Each message is processed by audit_receive_msg.
1106	* Malformed skbs with wrong length are discarded silently.
1107	*/
1108	static void audit_receive_skb(struct sk_buff *skb)
1109	{
1110	struct nlmsghdr *nlh;
1111	/*
1112	* len MUST be signed for nlmsg_next to be able to dec it below 0
1113	* if the nlmsg_len was not aligned
1114	*/
1115	int len;
1116	int err;
1117
1118	nlh = nlmsg_hdr(skb);
1119	len = skb->len;
1120
1121	while (nlmsg_ok(nlh, len)) {
1122	err = audit_receive_msg(skb, nlh);
1123	/* if err or if this message says it wants a response */
1124	if (err || (nlh->nlmsg_flags & NLM_F_ACK))
1125	netlink_ack(skb, nlh, err);
1126
1127	nlh = nlmsg_next(nlh, &len);
1128	}
1129	}
1130
1131	/* Receive messages from netlink socket. */
1132	static void audit_receive(struct sk_buff *skb)
1133	{
1134	mutex_lock(&audit_cmd_mutex);
1135	audit_receive_skb(skb);
1136	mutex_unlock(&audit_cmd_mutex);
1137	}
1138
1139	/* Run custom bind function on netlink socket group connect or bind requests. */
1140	static int audit_bind(struct net *net, int group)
1141	{
1142	if (!capable(CAP_AUDIT_READ))
1143	return -EPERM;
1144
1145	return 0;
1146	}
1147
1148	static int __net_init audit_net_init(struct net *net)
1149	{
1150	struct netlink_kernel_cfg cfg = {
1151	.input = audit_receive,
1152	.bind = audit_bind,
1153	.flags = NL_CFG_F_NONROOT_RECV,
1154	.groups = AUDIT_NLGRP_MAX,
1155	};
1156
1157	struct audit_net *aunet = net_generic(net, audit_net_id);
1158
1159	aunet->nlsk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
1160	if (aunet->nlsk == NULL) {
1161	audit_panic("cannot initialize netlink socket in namespace");
1162	return -ENOMEM;
1163	}
1164	aunet->nlsk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
1165	return 0;
1166	}
1167
1168	static void __net_exit audit_net_exit(struct net *net)
1169	{
1170	struct audit_net *aunet = net_generic(net, audit_net_id);
1171	struct sock *sock = aunet->nlsk;
1172	if (sock == audit_sock) {
1173	audit_pid = 0;
1174	audit_sock = NULL;
1175	}
1176
1177	RCU_INIT_POINTER(aunet->nlsk, NULL);
1178	synchronize_net();
1179	netlink_kernel_release(sock);
1180	}
1181
1182	static struct pernet_operations audit_net_ops __net_initdata = {
1183	.init = audit_net_init,
1184	.exit = audit_net_exit,
1185	.id = &audit_net_id,
1186	.size = sizeof(struct audit_net),
1187	};
1188
1189	/* Initialize audit support at boot time. */
1190	static int __init audit_init(void)
1191	{
1192	int i;
1193
1194	if (audit_initialized == AUDIT_DISABLED)
1195	return 0;
1196
1197	pr_info("initializing netlink subsys (%s)\n",
1198	audit_default ? "enabled" : "disabled");
1199	register_pernet_subsys(&audit_net_ops);
1200
1201	skb_queue_head_init(&audit_skb_queue);
1202	skb_queue_head_init(&audit_skb_hold_queue);
1203	audit_initialized = AUDIT_INITIALIZED;
1204
1205	audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized");
1206
1207	for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
1208	INIT_LIST_HEAD(&audit_inode_hash[i]);
1209
1210	return 0;
1211	}
1212	__initcall(audit_init);
1213
1214	/* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
1215	static int __init audit_enable(char *str)
1216	{
1217	audit_default = !!simple_strtol(str, NULL, 0);
1218	if (!audit_default)
1219	audit_initialized = AUDIT_DISABLED;
1220	audit_enabled = audit_default;
1221	audit_ever_enabled = !!audit_enabled;
1222
1223	pr_info("%s\n", audit_default ?
1224	"enabled (after initialization)" : "disabled (until reboot)");
1225
1226	return 1;
1227	}
1228	__setup("audit=", audit_enable);
1229
1230	/* Process kernel command-line parameter at boot time.
1231	* audit_backlog_limit=<n> */
1232	static int __init audit_backlog_limit_set(char *str)
1233	{
1234	u32 audit_backlog_limit_arg;
1235
1236	pr_info("audit_backlog_limit: ");
1237	if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
1238	pr_cont("using default of %u, unable to parse %s\n",
1239	audit_backlog_limit, str);
1240	return 1;
1241	}
1242
1243	audit_backlog_limit = audit_backlog_limit_arg;
1244	pr_cont("%d\n", audit_backlog_limit);
1245
1246	return 1;
1247	}
1248	__setup("audit_backlog_limit=", audit_backlog_limit_set);
1249
1250	static void audit_buffer_free(struct audit_buffer *ab)
1251	{
1252	unsigned long flags;
1253
1254	if (!ab)
1255	return;
1256
1257	kfree_skb(ab->skb);
1258	spin_lock_irqsave(&audit_freelist_lock, flags);
1259	if (audit_freelist_count > AUDIT_MAXFREE)
1260	kfree(ab);
1261	else {
1262	audit_freelist_count++;
1263	list_add(&ab->list, &audit_freelist);
1264	}
1265	spin_unlock_irqrestore(&audit_freelist_lock, flags);
1266	}
1267
1268	static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx,
1269	gfp_t gfp_mask, int type)
1270	{
1271	unsigned long flags;
1272	struct audit_buffer *ab = NULL;
1273	struct nlmsghdr *nlh;
1274
1275	spin_lock_irqsave(&audit_freelist_lock, flags);
1276	if (!list_empty(&audit_freelist)) {
1277	ab = list_entry(audit_freelist.next,
1278	struct audit_buffer, list);
1279	list_del(&ab->list);
1280	--audit_freelist_count;
1281	}
1282	spin_unlock_irqrestore(&audit_freelist_lock, flags);
1283
1284	if (!ab) {
1285	ab = kmalloc(sizeof(*ab), gfp_mask);
1286	if (!ab)
1287	goto err;
1288	}
1289
1290	ab->ctx = ctx;
1291	ab->gfp_mask = gfp_mask;
1292
1293	ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
1294	if (!ab->skb)
1295	goto err;
1296
1297	nlh = nlmsg_put(ab->skb, 0, 0, type, 0, 0);
1298	if (!nlh)
1299	goto out_kfree_skb;
1300
1301	return ab;
1302
1303	out_kfree_skb:
1304	kfree_skb(ab->skb);
1305	ab->skb = NULL;
1306	err:
1307	audit_buffer_free(ab);
1308	return NULL;
1309	}
1310
1311	/**
1312	* audit_serial - compute a serial number for the audit record
1313	*
1314	* Compute a serial number for the audit record. Audit records are
1315	* written to user-space as soon as they are generated, so a complete
1316	* audit record may be written in several pieces. The timestamp of the
1317	* record and this serial number are used by the user-space tools to
1318	* determine which pieces belong to the same audit record. The
1319	* (timestamp,serial) tuple is unique for each syscall and is live from
1320	* syscall entry to syscall exit.
1321	*
1322	* NOTE: Another possibility is to store the formatted records off the
1323	* audit context (for those records that have a context), and emit them
1324	* all at syscall exit. However, this could delay the reporting of
1325	* significant errors until syscall exit (or never, if the system
1326	* halts).
1327	*/
1328	unsigned int audit_serial(void)
1329	{
1330	static atomic_t serial = ATOMIC_INIT(0);
1331
1332	return atomic_add_return(1, &serial);
1333	}
1334
1335	static inline void audit_get_stamp(struct audit_context *ctx,
1336	struct timespec *t, unsigned int *serial)
1337	{
1338	if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
1339	*t = CURRENT_TIME;
1340	*serial = audit_serial();
1341	}
1342	}
1343
1344	/*
1345	* Wait for auditd to drain the queue a little
1346	*/
1347	static long wait_for_auditd(long sleep_time)
1348	{
1349	DECLARE_WAITQUEUE(wait, current);
1350
1351	if (audit_backlog_limit &&
1352	skb_queue_len(&audit_skb_queue) > audit_backlog_limit) {
1353	add_wait_queue_exclusive(&audit_backlog_wait, &wait);
1354	set_current_state(TASK_UNINTERRUPTIBLE);
1355	sleep_time = schedule_timeout(sleep_time);
1356	remove_wait_queue(&audit_backlog_wait, &wait);
1357	}
1358
1359	return sleep_time;
1360	}
1361
1362	/**
1363	* audit_log_start - obtain an audit buffer
1364	* @ctx: audit_context (may be NULL)
1365	* @gfp_mask: type of allocation
1366	* @type: audit message type
1367	*
1368	* Returns audit_buffer pointer on success or NULL on error.
1369	*
1370	* Obtain an audit buffer. This routine does locking to obtain the
1371	* audit buffer, but then no locking is required for calls to
1372	* audit_log_*format. If the task (ctx) is a task that is currently in a
1373	* syscall, then the syscall is marked as auditable and an audit record
1374	* will be written at syscall exit. If there is no associated task, then
1375	* task context (ctx) should be NULL.
1376	*/
1377	struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1378	int type)
1379	{
1380	struct audit_buffer *ab = NULL;
1381	struct timespec t;
1382	unsigned int uninitialized_var(serial);
1383	int reserve = 5; /* Allow atomic callers to go up to five
1384	entries over the normal backlog limit */
1385	unsigned long timeout_start = jiffies;
1386
1387	if (audit_initialized != AUDIT_INITIALIZED)
1388	return NULL;
1389
1390	if (unlikely(!audit_filter(type, AUDIT_FILTER_TYPE)))
1391	return NULL;
1392
1393	if (gfp_mask & __GFP_DIRECT_RECLAIM) {
1394	if (audit_pid && audit_pid == current->tgid)
1395	gfp_mask &= ~__GFP_DIRECT_RECLAIM;
1396	else
1397	reserve = 0;
1398	}
1399
1400	while (audit_backlog_limit
1401	&& skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) {
1402	if (gfp_mask & __GFP_DIRECT_RECLAIM && audit_backlog_wait_time) {
1403	long sleep_time;
1404
1405	sleep_time = timeout_start + audit_backlog_wait_time - jiffies;
1406	if (sleep_time > 0) {
1407	sleep_time = wait_for_auditd(sleep_time);
1408	if (sleep_time > 0)
1409	continue;
1410	}
1411	}
1412	if (audit_rate_check() && printk_ratelimit())
1413	pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
1414	skb_queue_len(&audit_skb_queue),
1415	audit_backlog_limit);
1416	audit_log_lost("backlog limit exceeded");
1417	audit_backlog_wait_time = 0;
1418	wake_up(&audit_backlog_wait);
1419	return NULL;
1420	}
1421
1422	if (!reserve && !audit_backlog_wait_time)
1423	audit_backlog_wait_time = audit_backlog_wait_time_master;
1424
1425	ab = audit_buffer_alloc(ctx, gfp_mask, type);
1426	if (!ab) {
1427	audit_log_lost("out of memory in audit_log_start");
1428	return NULL;
1429	}
1430
1431	audit_get_stamp(ab->ctx, &t, &serial);
1432
1433	audit_log_format(ab, "audit(%lu.%03lu:%u): ",
1434	t.tv_sec, t.tv_nsec/1000000, serial);
1435	return ab;
1436	}
1437
1438	/**
1439	* audit_expand - expand skb in the audit buffer
1440	* @ab: audit_buffer
1441	* @extra: space to add at tail of the skb
1442	*
1443	* Returns 0 (no space) on failed expansion, or available space if
1444	* successful.
1445	*/
1446	static inline int audit_expand(struct audit_buffer *ab, int extra)
1447	{
1448	struct sk_buff *skb = ab->skb;
1449	int oldtail = skb_tailroom(skb);
1450	int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1451	int newtail = skb_tailroom(skb);
1452
1453	if (ret < 0) {
1454	audit_log_lost("out of memory in audit_expand");
1455	return 0;
1456	}
1457
1458	skb->truesize += newtail - oldtail;
1459	return newtail;
1460	}
1461
1462	/*
1463	* Format an audit message into the audit buffer. If there isn't enough
1464	* room in the audit buffer, more room will be allocated and vsnprint
1465	* will be called a second time. Currently, we assume that a printk
1466	* can't format message larger than 1024 bytes, so we don't either.
1467	*/
1468	static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1469	va_list args)
1470	{
1471	int len, avail;
1472	struct sk_buff *skb;
1473	va_list args2;
1474
1475	if (!ab)
1476	return;
1477
1478	BUG_ON(!ab->skb);
1479	skb = ab->skb;
1480	avail = skb_tailroom(skb);
1481	if (avail == 0) {
1482	avail = audit_expand(ab, AUDIT_BUFSIZ);
1483	if (!avail)
1484	goto out;
1485	}
1486	va_copy(args2, args);
1487	len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1488	if (len >= avail) {
1489	/* The printk buffer is 1024 bytes long, so if we get
1490	* here and AUDIT_BUFSIZ is at least 1024, then we can
1491	* log everything that printk could have logged. */
1492	avail = audit_expand(ab,
1493	max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1494	if (!avail)
1495	goto out_va_end;
1496	len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1497	}
1498	if (len > 0)
1499	skb_put(skb, len);
1500	out_va_end:
1501	va_end(args2);
1502	out:
1503	return;
1504	}
1505
1506	/**
1507	* audit_log_format - format a message into the audit buffer.
1508	* @ab: audit_buffer
1509	* @fmt: format string
1510	* @...: optional parameters matching @fmt string
1511	*
1512	* All the work is done in audit_log_vformat.
1513	*/
1514	void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1515	{
1516	va_list args;
1517
1518	if (!ab)
1519	return;
1520	va_start(args, fmt);
1521	audit_log_vformat(ab, fmt, args);
1522	va_end(args);
1523	}
1524
1525	/**
1526	* audit_log_hex - convert a buffer to hex and append it to the audit skb
1527	* @ab: the audit_buffer
1528	* @buf: buffer to convert to hex
1529	* @len: length of @buf to be converted
1530	*
1531	* No return value; failure to expand is silently ignored.
1532	*
1533	* This function will take the passed buf and convert it into a string of
1534	* ascii hex digits. The new string is placed onto the skb.
1535	*/
1536	void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
1537	size_t len)
1538	{
1539	int i, avail, new_len;
1540	unsigned char *ptr;
1541	struct sk_buff *skb;
1542
1543	if (!ab)
1544	return;
1545
1546	BUG_ON(!ab->skb);
1547	skb = ab->skb;
1548	avail = skb_tailroom(skb);
1549	new_len = len<<1;
1550	if (new_len >= avail) {
1551	/* Round the buffer request up to the next multiple */
1552	new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1553	avail = audit_expand(ab, new_len);
1554	if (!avail)
1555	return;
1556	}
1557
1558	ptr = skb_tail_pointer(skb);
1559	for (i = 0; i < len; i++)
1560	ptr = hex_byte_pack_upper(ptr, buf[i]);
1561	*ptr = 0;
1562	skb_put(skb, len << 1); /* new string is twice the old string */
1563	}
1564
1565	/*
1566	* Format a string of no more than slen characters into the audit buffer,
1567	* enclosed in quote marks.
1568	*/
1569	void audit_log_n_string(struct audit_buffer *ab, const char *string,
1570	size_t slen)
1571	{
1572	int avail, new_len;
1573	unsigned char *ptr;
1574	struct sk_buff *skb;
1575
1576	if (!ab)
1577	return;
1578
1579	BUG_ON(!ab->skb);
1580	skb = ab->skb;
1581	avail = skb_tailroom(skb);
1582	new_len = slen + 3; /* enclosing quotes + null terminator */
1583	if (new_len > avail) {
1584	avail = audit_expand(ab, new_len);
1585	if (!avail)
1586	return;
1587	}
1588	ptr = skb_tail_pointer(skb);
1589	*ptr++ = '"';
1590	memcpy(ptr, string, slen);
1591	ptr += slen;
1592	*ptr++ = '"';
1593	*ptr = 0;
1594	skb_put(skb, slen + 2); /* don't include null terminator */
1595	}
1596
1597	/**
1598	* audit_string_contains_control - does a string need to be logged in hex
1599	* @string: string to be checked
1600	* @len: max length of the string to check
1601	*/
1602	bool audit_string_contains_control(const char *string, size_t len)
1603	{
1604	const unsigned char *p;
1605	for (p = string; p < (const unsigned char *)string + len; p++) {
1606	if (*p == '"' || *p < 0x21 || *p > 0x7e)
1607	return true;
1608	}
1609	return false;
1610	}
1611
1612	/**
1613	* audit_log_n_untrustedstring - log a string that may contain random characters
1614	* @ab: audit_buffer
1615	* @len: length of string (not including trailing null)
1616	* @string: string to be logged
1617	*
1618	* This code will escape a string that is passed to it if the string
1619	* contains a control character, unprintable character, double quote mark,
1620	* or a space. Unescaped strings will start and end with a double quote mark.
1621	* Strings that are escaped are printed in hex (2 digits per char).
1622	*
1623	* The caller specifies the number of characters in the string to log, which may
1624	* or may not be the entire string.
1625	*/
1626	void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
1627	size_t len)
1628	{
1629	if (audit_string_contains_control(string, len))
1630	audit_log_n_hex(ab, string, len);
1631	else
1632	audit_log_n_string(ab, string, len);
1633	}
1634
1635	/**
1636	* audit_log_untrustedstring - log a string that may contain random characters
1637	* @ab: audit_buffer
1638	* @string: string to be logged
1639	*
1640	* Same as audit_log_n_untrustedstring(), except that strlen is used to
1641	* determine string length.
1642	*/
1643	void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
1644	{
1645	audit_log_n_untrustedstring(ab, string, strlen(string));
1646	}
1647
1648	/* This is a helper-function to print the escaped d_path */
1649	void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
1650	const struct path *path)
1651	{
1652	char *p, *pathname;
1653
1654	if (prefix)
1655	audit_log_format(ab, "%s", prefix);
1656
1657	/* We will allow 11 spaces for ' (deleted)' to be appended */
1658	pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
1659	if (!pathname) {
1660	audit_log_string(ab, "<no_memory>");
1661	return;
1662	}
1663	p = d_path(path, pathname, PATH_MAX+11);
1664	if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
1665	/* FIXME: can we save some information here? */
1666	audit_log_string(ab, "<too_long>");
1667	} else
1668	audit_log_untrustedstring(ab, p);
1669	kfree(pathname);
1670	}
1671
1672	void audit_log_session_info(struct audit_buffer *ab)
1673	{
1674	unsigned int sessionid = audit_get_sessionid(current);
1675	uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
1676
1677	audit_log_format(ab, " auid=%u ses=%u", auid, sessionid);
1678	}
1679
1680	void audit_log_key(struct audit_buffer *ab, char *key)
1681	{
1682	audit_log_format(ab, " key=");
1683	if (key)
1684	audit_log_untrustedstring(ab, key);
1685	else
1686	audit_log_format(ab, "(null)");
1687	}
1688
1689	void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap)
1690	{
1691	int i;
1692
1693	audit_log_format(ab, " %s=", prefix);
1694	CAP_FOR_EACH_U32(i) {
1695	audit_log_format(ab, "%08x",
1696	cap->cap[CAP_LAST_U32 - i]);
1697	}
1698	}
1699
1700	static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
1701	{
1702	kernel_cap_t *perm = &name->fcap.permitted;
1703	kernel_cap_t *inh = &name->fcap.inheritable;
1704	int log = 0;
1705
1706	if (!cap_isclear(*perm)) {
1707	audit_log_cap(ab, "cap_fp", perm);
1708	log = 1;
1709	}
1710	if (!cap_isclear(*inh)) {
1711	audit_log_cap(ab, "cap_fi", inh);
1712	log = 1;
1713	}
1714
1715	if (log)
1716	audit_log_format(ab, " cap_fe=%d cap_fver=%x",
1717	name->fcap.fE, name->fcap_ver);
1718	}
1719
1720	static inline int audit_copy_fcaps(struct audit_names *name,
1721	const struct dentry *dentry)
1722	{
1723	struct cpu_vfs_cap_data caps;
1724	int rc;
1725
1726	if (!dentry)
1727	return 0;
1728
1729	rc = get_vfs_caps_from_disk(dentry, &caps);
1730	if (rc)
1731	return rc;
1732
1733	name->fcap.permitted = caps.permitted;
1734	name->fcap.inheritable = caps.inheritable;
1735	name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
1736	name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >>
1737	VFS_CAP_REVISION_SHIFT;
1738
1739	return 0;
1740	}
1741
1742	/* Copy inode data into an audit_names. */
1743	void audit_copy_inode(struct audit_names *name, const struct dentry *dentry,
1744	struct inode *inode)
1745	{
1746	name->ino = inode->i_ino;
1747	name->dev = inode->i_sb->s_dev;
1748	name->mode = inode->i_mode;
1749	name->uid = inode->i_uid;
1750	name->gid = inode->i_gid;
1751	name->rdev = inode->i_rdev;
1752	security_inode_getsecid(inode, &name->osid);
1753	audit_copy_fcaps(name, dentry);
1754	}
1755
1756	/**
1757	* audit_log_name - produce AUDIT_PATH record from struct audit_names
1758	* @context: audit_context for the task
1759	* @n: audit_names structure with reportable details
1760	* @path: optional path to report instead of audit_names->name
1761	* @record_num: record number to report when handling a list of names
1762	* @call_panic: optional pointer to int that will be updated if secid fails
1763	*/
1764	void audit_log_name(struct audit_context *context, struct audit_names *n,
1765	struct path *path, int record_num, int *call_panic)
1766	{
1767	struct audit_buffer *ab;
1768	ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH);
1769	if (!ab)
1770	return;
1771
1772	audit_log_format(ab, "item=%d", record_num);
1773
1774	if (path)
1775	audit_log_d_path(ab, " name=", path);
1776	else if (n->name) {
1777	switch (n->name_len) {
1778	case AUDIT_NAME_FULL:
1779	/* log the full path */
1780	audit_log_format(ab, " name=");
1781	audit_log_untrustedstring(ab, n->name->name);
1782	break;
1783	case 0:
1784	/* name was specified as a relative path and the
1785	* directory component is the cwd */
1786	audit_log_d_path(ab, " name=", &context->pwd);
1787	break;
1788	default:
1789	/* log the name's directory component */
1790	audit_log_format(ab, " name=");
1791	audit_log_n_untrustedstring(ab, n->name->name,
1792	n->name_len);
1793	}
1794	} else
1795	audit_log_format(ab, " name=(null)");
1796
1797	if (n->ino != AUDIT_INO_UNSET)
1798	audit_log_format(ab, " inode=%lu"
1799	" dev=%02x:%02x mode=%#ho"
1800	" ouid=%u ogid=%u rdev=%02x:%02x",
1801	n->ino,
1802	MAJOR(n->dev),
1803	MINOR(n->dev),
1804	n->mode,
1805	from_kuid(&init_user_ns, n->uid),
1806	from_kgid(&init_user_ns, n->gid),
1807	MAJOR(n->rdev),
1808	MINOR(n->rdev));
1809	if (n->osid != 0) {
1810	char *ctx = NULL;
1811	u32 len;
1812	if (security_secid_to_secctx(
1813	n->osid, &ctx, &len)) {
1814	audit_log_format(ab, " osid=%u", n->osid);
1815	if (call_panic)
1816	*call_panic = 2;
1817	} else {
1818	audit_log_format(ab, " obj=%s", ctx);
1819	security_release_secctx(ctx, len);
1820	}
1821	}
1822
1823	/* log the audit_names record type */
1824	audit_log_format(ab, " nametype=");
1825	switch(n->type) {
1826	case AUDIT_TYPE_NORMAL:
1827	audit_log_format(ab, "NORMAL");
1828	break;
1829	case AUDIT_TYPE_PARENT:
1830	audit_log_format(ab, "PARENT");
1831	break;
1832	case AUDIT_TYPE_CHILD_DELETE:
1833	audit_log_format(ab, "DELETE");
1834	break;
1835	case AUDIT_TYPE_CHILD_CREATE:
1836	audit_log_format(ab, "CREATE");
1837	break;
1838	default:
1839	audit_log_format(ab, "UNKNOWN");
1840	break;
1841	}
1842
1843	audit_log_fcaps(ab, n);
1844	audit_log_end(ab);
1845	}
1846
1847	int audit_log_task_context(struct audit_buffer *ab)
1848	{
1849	char *ctx = NULL;
1850	unsigned len;
1851	int error;
1852	u32 sid;
1853
1854	security_task_getsecid(current, &sid);
1855	if (!sid)
1856	return 0;
1857
1858	error = security_secid_to_secctx(sid, &ctx, &len);
1859	if (error) {
1860	if (error != -EINVAL)
1861	goto error_path;
1862	return 0;
1863	}
1864
1865	audit_log_format(ab, " subj=%s", ctx);
1866	security_release_secctx(ctx, len);
1867	return 0;
1868
1869	error_path:
1870	audit_panic("error in audit_log_task_context");
1871	return error;
1872	}
1873	EXPORT_SYMBOL(audit_log_task_context);
1874
1875	void audit_log_d_path_exe(struct audit_buffer *ab,
1876	struct mm_struct *mm)
1877	{
1878	struct file *exe_file;
1879
1880	if (!mm)
1881	goto out_null;
1882
1883	exe_file = get_mm_exe_file(mm);
1884	if (!exe_file)
1885	goto out_null;
1886
1887	audit_log_d_path(ab, " exe=", &exe_file->f_path);
1888	fput(exe_file);
1889	return;
1890	out_null:
1891	audit_log_format(ab, " exe=(null)");
1892	}
1893
1894	struct tty_struct *audit_get_tty(struct task_struct *tsk)
1895	{
1896	struct tty_struct *tty = NULL;
1897	unsigned long flags;
1898
1899	spin_lock_irqsave(&tsk->sighand->siglock, flags);
1900	if (tsk->signal)
1901	tty = tty_kref_get(tsk->signal->tty);
1902	spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
1903	return tty;
1904	}
1905
1906	void audit_put_tty(struct tty_struct *tty)
1907	{
1908	tty_kref_put(tty);
1909	}
1910
1911	void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
1912	{
1913	const struct cred *cred;
1914	char comm[sizeof(tsk->comm)];
1915	struct tty_struct *tty;
1916
1917	if (!ab)
1918	return;
1919
1920	/* tsk == current */
1921	cred = current_cred();
1922	tty = audit_get_tty(tsk);
1923	audit_log_format(ab,
1924	" ppid=%d pid=%d auid=%u uid=%u gid=%u"
1925	" euid=%u suid=%u fsuid=%u"
1926	" egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
1927	task_ppid_nr(tsk),
1928	task_tgid_nr(tsk),
1929	from_kuid(&init_user_ns, audit_get_loginuid(tsk)),
1930	from_kuid(&init_user_ns, cred->uid),
1931	from_kgid(&init_user_ns, cred->gid),
1932	from_kuid(&init_user_ns, cred->euid),
1933	from_kuid(&init_user_ns, cred->suid),
1934	from_kuid(&init_user_ns, cred->fsuid),
1935	from_kgid(&init_user_ns, cred->egid),
1936	from_kgid(&init_user_ns, cred->sgid),
1937	from_kgid(&init_user_ns, cred->fsgid),
1938	tty ? tty_name(tty) : "(none)",
1939	audit_get_sessionid(tsk));
1940	audit_put_tty(tty);
1941	audit_log_format(ab, " comm=");
1942	audit_log_untrustedstring(ab, get_task_comm(comm, tsk));
1943	audit_log_d_path_exe(ab, tsk->mm);
1944	audit_log_task_context(ab);
1945	}
1946	EXPORT_SYMBOL(audit_log_task_info);
1947
1948	/**
1949	* audit_log_link_denied - report a link restriction denial
1950	* @operation: specific link operation
1951	* @link: the path that triggered the restriction
1952	*/
1953	void audit_log_link_denied(const char *operation, struct path *link)
1954	{
1955	struct audit_buffer *ab;
1956	struct audit_names *name;
1957
1958	name = kzalloc(sizeof(*name), GFP_NOFS);
1959	if (!name)
1960	return;
1961
1962	/* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */
1963	ab = audit_log_start(current->audit_context, GFP_KERNEL,
1964	AUDIT_ANOM_LINK);
1965	if (!ab)
1966	goto out;
1967	audit_log_format(ab, "op=%s", operation);
1968	audit_log_task_info(ab, current);
1969	audit_log_format(ab, " res=0");
1970	audit_log_end(ab);
1971
1972	/* Generate AUDIT_PATH record with object. */
1973	name->type = AUDIT_TYPE_NORMAL;
1974	audit_copy_inode(name, link->dentry, d_backing_inode(link->dentry));
1975	audit_log_name(current->audit_context, name, link, 0, NULL);
1976	out:
1977	kfree(name);
1978	}
1979
1980	/**
1981	* audit_log_end - end one audit record
1982	* @ab: the audit_buffer
1983	*
1984	* netlink_unicast() cannot be called inside an irq context because it blocks
1985	* (last arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed
1986	* on a queue and a tasklet is scheduled to remove them from the queue outside
1987	* the irq context. May be called in any context.
1988	*/
1989	void audit_log_end(struct audit_buffer *ab)
1990	{
1991	if (!ab)
1992	return;
1993	if (!audit_rate_check()) {
1994	audit_log_lost("rate limit exceeded");
1995	} else {
1996	struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
1997
1998	nlh->nlmsg_len = ab->skb->len;
1999	kauditd_send_multicast_skb(ab->skb, ab->gfp_mask);
2000
2001	/*
2002	* The original kaudit unicast socket sends up messages with
2003	* nlmsg_len set to the payload length rather than the entire
2004	* message length. This breaks the standard set by netlink.
2005	* The existing auditd daemon assumes this breakage. Fixing
2006	* this would require co-ordinating a change in the established
2007	* protocol between the kaudit kernel subsystem and the auditd
2008	* userspace code.
2009	*/
2010	nlh->nlmsg_len -= NLMSG_HDRLEN;
2011
2012	if (audit_pid) {
2013	skb_queue_tail(&audit_skb_queue, ab->skb);
2014	wake_up_interruptible(&kauditd_wait);
2015	} else {
2016	audit_printk_skb(ab->skb);
2017	}
2018	ab->skb = NULL;
2019	}
2020	audit_buffer_free(ab);
2021	}
2022
2023	/**
2024	* audit_log - Log an audit record
2025	* @ctx: audit context
2026	* @gfp_mask: type of allocation
2027	* @type: audit message type
2028	* @fmt: format string to use
2029	* @...: variable parameters matching the format string
2030	*
2031	* This is a convenience function that calls audit_log_start,
2032	* audit_log_vformat, and audit_log_end. It may be called
2033	* in any context.
2034	*/
2035	void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
2036	const char *fmt, ...)
2037	{
2038	struct audit_buffer *ab;
2039	va_list args;
2040
2041	ab = audit_log_start(ctx, gfp_mask, type);
2042	if (ab) {
2043	va_start(args, fmt);
2044	audit_log_vformat(ab, fmt, args);
2045	va_end(args);
2046	audit_log_end(ab);
2047	}
2048	}
2049
2050	#ifdef CONFIG_SECURITY
2051	/**
2052	* audit_log_secctx - Converts and logs SELinux context
2053	* @ab: audit_buffer
2054	* @secid: security number
2055	*
2056	* This is a helper function that calls security_secid_to_secctx to convert
2057	* secid to secctx and then adds the (converted) SELinux context to the audit
2058	* log by calling audit_log_format, thus also preventing leak of internal secid
2059	* to userspace. If secid cannot be converted audit_panic is called.
2060	*/
2061	void audit_log_secctx(struct audit_buffer *ab, u32 secid)
2062	{
2063	u32 len;
2064	char *secctx;
2065
2066	if (security_secid_to_secctx(secid, &secctx, &len)) {
2067	audit_panic("Cannot convert secid to context");
2068	} else {
2069	audit_log_format(ab, " obj=%s", secctx);
2070	security_release_secctx(secctx, len);
2071	}
2072	}
2073	EXPORT_SYMBOL(audit_log_secctx);
2074	#endif
2075
2076	EXPORT_SYMBOL(audit_log_start);
2077	EXPORT_SYMBOL(audit_log_end);
2078	EXPORT_SYMBOL(audit_log_format);
2079	EXPORT_SYMBOL(audit_log);
2080