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Root/kernel/audit.c

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	#include <linux/init.h>
45	#include <asm/types.h>
46	#include <asm/atomic.h>
47	#include <linux/mm.h>
48	#include <linux/module.h>
49	#include <linux/slab.h>
50	#include <linux/err.h>
51	#include <linux/kthread.h>
52
53	#include <linux/audit.h>
54
55	#include <net/sock.h>
56	#include <net/netlink.h>
57	#include <linux/skbuff.h>
58	#include <linux/netlink.h>
59	#include <linux/freezer.h>
60	#include <linux/tty.h>
61
62	#include "audit.h"
63
64	/* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
65	* (Initialization happens after skb_init is called.) */
66	#define AUDIT_DISABLED -1
67	#define AUDIT_UNINITIALIZED 0
68	#define AUDIT_INITIALIZED 1
69	static int audit_initialized;
70
71	#define AUDIT_OFF 0
72	#define AUDIT_ON 1
73	#define AUDIT_LOCKED 2
74	int audit_enabled;
75	int audit_ever_enabled;
76
77	/* Default state when kernel boots without any parameters. */
78	static int audit_default;
79
80	/* If auditing cannot proceed, audit_failure selects what happens. */
81	static int audit_failure = AUDIT_FAIL_PRINTK;
82
83	/*
84	* If audit records are to be written to the netlink socket, audit_pid
85	* contains the pid of the auditd process and audit_nlk_pid contains
86	* the pid to use to send netlink messages to that process.
87	*/
88	int audit_pid;
89	static int audit_nlk_pid;
90
91	/* If audit_rate_limit is non-zero, limit the rate of sending audit records
92	* to that number per second. This prevents DoS attacks, but results in
93	* audit records being dropped. */
94	static int audit_rate_limit;
95
96	/* Number of outstanding audit_buffers allowed. */
97	static int audit_backlog_limit = 64;
98	static int audit_backlog_wait_time = 60 * HZ;
99	static int audit_backlog_wait_overflow = 0;
100
101	/* The identity of the user shutting down the audit system. */
102	uid_t audit_sig_uid = -1;
103	pid_t audit_sig_pid = -1;
104	u32 audit_sig_sid = 0;
105
106	/* Records can be lost in several ways:
107	0) [suppressed in audit_alloc]
108	1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
109	2) out of memory in audit_log_move [alloc_skb]
110	3) suppressed due to audit_rate_limit
111	4) suppressed due to audit_backlog_limit
112	*/
113	static atomic_t audit_lost = ATOMIC_INIT(0);
114
115	/* The netlink socket. */
116	static struct sock *audit_sock;
117
118	/* Hash for inode-based rules */
119	struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
120
121	/* The audit_freelist is a list of pre-allocated audit buffers (if more
122	* than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
123	* being placed on the freelist). */
124	static DEFINE_SPINLOCK(audit_freelist_lock);
125	static int audit_freelist_count;
126	static LIST_HEAD(audit_freelist);
127
128	static struct sk_buff_head audit_skb_queue;
129	/* queue of skbs to send to auditd when/if it comes back */
130	static struct sk_buff_head audit_skb_hold_queue;
131	static struct task_struct *kauditd_task;
132	static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
133	static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
134
135	/* Serialize requests from userspace. */
136	DEFINE_MUTEX(audit_cmd_mutex);
137
138	/* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
139	* audit records. Since printk uses a 1024 byte buffer, this buffer
140	* should be at least that large. */
141	#define AUDIT_BUFSIZ 1024
142
143	/* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the
144	* audit_freelist. Doing so eliminates many kmalloc/kfree calls. */
145	#define AUDIT_MAXFREE (2*NR_CPUS)
146
147	/* The audit_buffer is used when formatting an audit record. The caller
148	* locks briefly to get the record off the freelist or to allocate the
149	* buffer, and locks briefly to send the buffer to the netlink layer or
150	* to place it on a transmit queue. Multiple audit_buffers can be in
151	* use simultaneously. */
152	struct audit_buffer {
153	struct list_head list;
154	struct sk_buff skb; / formatted skb ready to send */
155	struct audit_context ctx; / NULL or associated context */
156	gfp_t gfp_mask;
157	};
158
159	struct audit_reply {
160	int pid;
161	struct sk_buff *skb;
162	};
163
164	static void audit_set_pid(struct audit_buffer *ab, pid_t pid)
165	{
166	if (ab) {
167	struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
168	nlh->nlmsg_pid = pid;
169	}
170	}
171
172	void audit_panic(const char *message)
173	{
174	switch (audit_failure)
175	{
176	case AUDIT_FAIL_SILENT:
177	break;
178	case AUDIT_FAIL_PRINTK:
179	if (printk_ratelimit())
180	printk(KERN_ERR "audit: %s\n", message);
181	break;
182	case AUDIT_FAIL_PANIC:
183	/* test audit_pid since printk is always losey, why bother? */
184	if (audit_pid)
185	panic("audit: %s\n", message);
186	break;
187	}
188	}
189
190	static inline int audit_rate_check(void)
191	{
192	static unsigned long last_check = 0;
193	static int messages = 0;
194	static DEFINE_SPINLOCK(lock);
195	unsigned long flags;
196	unsigned long now;
197	unsigned long elapsed;
198	int retval = 0;
199
200	if (!audit_rate_limit) return 1;
201
202	spin_lock_irqsave(&lock, flags);
203	if (++messages < audit_rate_limit) {
204	retval = 1;
205	} else {
206	now = jiffies;
207	elapsed = now - last_check;
208	if (elapsed > HZ) {
209	last_check = now;
210	messages = 0;
211	retval = 1;
212	}
213	}
214	spin_unlock_irqrestore(&lock, flags);
215
216	return retval;
217	}
218
219	/**
220	* audit_log_lost - conditionally log lost audit message event
221	* @message: the message stating reason for lost audit message
222	*
223	* Emit at least 1 message per second, even if audit_rate_check is
224	* throttling.
225	* Always increment the lost messages counter.
226	*/
227	void audit_log_lost(const char *message)
228	{
229	static unsigned long last_msg = 0;
230	static DEFINE_SPINLOCK(lock);
231	unsigned long flags;
232	unsigned long now;
233	int print;
234
235	atomic_inc(&audit_lost);
236
237	print = (audit_failure == AUDIT_FAIL_PANIC \|\| !audit_rate_limit);
238
239	if (!print) {
240	spin_lock_irqsave(&lock, flags);
241	now = jiffies;
242	if (now - last_msg > HZ) {
243	print = 1;
244	last_msg = now;
245	}
246	spin_unlock_irqrestore(&lock, flags);
247	}
248
249	if (print) {
250	if (printk_ratelimit())
251	printk(KERN_WARNING
252	"audit: audit_lost=%d audit_rate_limit=%d "
253	"audit_backlog_limit=%d\n",
254	atomic_read(&audit_lost),
255	audit_rate_limit,
256	audit_backlog_limit);
257	audit_panic(message);
258	}
259	}
260
261	static int audit_log_config_change(char *function_name, int new, int old,
262	uid_t loginuid, u32 sessionid, u32 sid,
263	int allow_changes)
264	{
265	struct audit_buffer *ab;
266	int rc = 0;
267
268	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
269	audit_log_format(ab, "%s=%d old=%d auid=%u ses=%u", function_name, new,
270	old, loginuid, sessionid);
271	if (sid) {
272	char *ctx = NULL;
273	u32 len;
274
275	rc = security_secid_to_secctx(sid, &ctx, &len);
276	if (rc) {
277	audit_log_format(ab, " sid=%u", sid);
278	allow_changes = 0; /* Something weird, deny request */
279	} else {
280	audit_log_format(ab, " subj=%s", ctx);
281	security_release_secctx(ctx, len);
282	}
283	}
284	audit_log_format(ab, " res=%d", allow_changes);
285	audit_log_end(ab);
286	return rc;
287	}
288
289	static int audit_do_config_change(char function_name, int to_change,
290	int new, uid_t loginuid, u32 sessionid,
291	u32 sid)
292	{
293	int allow_changes, rc = 0, old = *to_change;
294
295	/* check if we are locked */
296	if (audit_enabled == AUDIT_LOCKED)
297	allow_changes = 0;
298	else
299	allow_changes = 1;
300
301	if (audit_enabled != AUDIT_OFF) {
302	rc = audit_log_config_change(function_name, new, old, loginuid,
303	sessionid, sid, allow_changes);
304	if (rc)
305	allow_changes = 0;
306	}
307
308	/* If we are allowed, make the change */
309	if (allow_changes == 1)
310	*to_change = new;
311	/* Not allowed, update reason */
312	else if (rc == 0)
313	rc = -EPERM;
314	return rc;
315	}
316
317	static int audit_set_rate_limit(int limit, uid_t loginuid, u32 sessionid,
318	u32 sid)
319	{
320	return audit_do_config_change("audit_rate_limit", &audit_rate_limit,
321	limit, loginuid, sessionid, sid);
322	}
323
324	static int audit_set_backlog_limit(int limit, uid_t loginuid, u32 sessionid,
325	u32 sid)
326	{
327	return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit,
328	limit, loginuid, sessionid, sid);
329	}
330
331	static int audit_set_enabled(int state, uid_t loginuid, u32 sessionid, u32 sid)
332	{
333	int rc;
334	if (state < AUDIT_OFF \|\| state > AUDIT_LOCKED)
335	return -EINVAL;
336
337	rc = audit_do_config_change("audit_enabled", &audit_enabled, state,
338	loginuid, sessionid, sid);
339
340	if (!rc)
341	audit_ever_enabled \|= !!state;
342
343	return rc;
344	}
345
346	static int audit_set_failure(int state, uid_t loginuid, u32 sessionid, u32 sid)
347	{
348	if (state != AUDIT_FAIL_SILENT
349	&& state != AUDIT_FAIL_PRINTK
350	&& state != AUDIT_FAIL_PANIC)
351	return -EINVAL;
352
353	return audit_do_config_change("audit_failure", &audit_failure, state,
354	loginuid, sessionid, sid);
355	}
356
357	/*
358	* Queue skbs to be sent to auditd when/if it comes back. These skbs should
359	* already have been sent via prink/syslog and so if these messages are dropped
360	* it is not a huge concern since we already passed the audit_log_lost()
361	* notification and stuff. This is just nice to get audit messages during
362	* boot before auditd is running or messages generated while auditd is stopped.
363	* This only holds messages is audit_default is set, aka booting with audit=1
364	* or building your kernel that way.
365	*/
366	static void audit_hold_skb(struct sk_buff *skb)
367	{
368	if (audit_default &&
369	skb_queue_len(&audit_skb_hold_queue) < audit_backlog_limit)
370	skb_queue_tail(&audit_skb_hold_queue, skb);
371	else
372	kfree_skb(skb);
373	}
374
375	/*
376	* For one reason or another this nlh isn't getting delivered to the userspace
377	* audit daemon, just send it to printk.
378	*/
379	static void audit_printk_skb(struct sk_buff *skb)
380	{
381	struct nlmsghdr *nlh = nlmsg_hdr(skb);
382	char *data = NLMSG_DATA(nlh);
383
384	if (nlh->nlmsg_type != AUDIT_EOE) {
385	if (printk_ratelimit())
386	printk(KERN_NOTICE "type=%d %s\n", nlh->nlmsg_type, data);
387	else
388	audit_log_lost("printk limit exceeded\n");
389	}
390
391	audit_hold_skb(skb);
392	}
393
394	static void kauditd_send_skb(struct sk_buff *skb)
395	{
396	int err;
397	/* take a reference in case we can't send it and we want to hold it */
398	skb_get(skb);
399	err = netlink_unicast(audit_sock, skb, audit_nlk_pid, 0);
400	if (err < 0) {
401	BUG_ON(err != -ECONNREFUSED); /* Shouldn't happen */
402	printk(KERN_ERR "audit: NO daemon at audit_pid=%d\n", audit_pid);
403	audit_log_lost("auditd disappeared\n");
404	audit_pid = 0;
405	/* we might get lucky and get this in the next auditd */
406	audit_hold_skb(skb);
407	} else
408	/* drop the extra reference if sent ok */
409	consume_skb(skb);
410	}
411
412	static int kauditd_thread(void *dummy)
413	{
414	struct sk_buff *skb;
415
416	set_freezable();
417	while (!kthread_should_stop()) {
418	/*
419	* if auditd just started drain the queue of messages already
420	* sent to syslog/printk. remember loss here is ok. we already
421	* called audit_log_lost() if it didn't go out normally. so the
422	* race between the skb_dequeue and the next check for audit_pid
423	* doesn't matter.
424	*
425	* if you ever find kauditd to be too slow we can get a perf win
426	* by doing our own locking and keeping better track if there
427	* are messages in this queue. I don't see the need now, but
428	* in 5 years when I want to play with this again I'll see this
429	* note and still have no friggin idea what i'm thinking today.
430	*/
431	if (audit_default && audit_pid) {
432	skb = skb_dequeue(&audit_skb_hold_queue);
433	if (unlikely(skb)) {
434	while (skb && audit_pid) {
435	kauditd_send_skb(skb);
436	skb = skb_dequeue(&audit_skb_hold_queue);
437	}
438	}
439	}
440
441	skb = skb_dequeue(&audit_skb_queue);
442	wake_up(&audit_backlog_wait);
443	if (skb) {
444	if (audit_pid)
445	kauditd_send_skb(skb);
446	else
447	audit_printk_skb(skb);
448	} else {
449	DECLARE_WAITQUEUE(wait, current);
450	set_current_state(TASK_INTERRUPTIBLE);
451	add_wait_queue(&kauditd_wait, &wait);
452
453	if (!skb_queue_len(&audit_skb_queue)) {
454	try_to_freeze();
455	schedule();
456	}
457
458	__set_current_state(TASK_RUNNING);
459	remove_wait_queue(&kauditd_wait, &wait);
460	}
461	}
462	return 0;
463	}
464
465	static int audit_prepare_user_tty(pid_t pid, uid_t loginuid, u32 sessionid)
466	{
467	struct task_struct *tsk;
468	int err;
469
470	rcu_read_lock();
471	tsk = find_task_by_vpid(pid);
472	if (!tsk) {
473	rcu_read_unlock();
474	return -ESRCH;
475	}
476	get_task_struct(tsk);
477	rcu_read_unlock();
478	err = tty_audit_push_task(tsk, loginuid, sessionid);
479	put_task_struct(tsk);
480	return err;
481	}
482
483	int audit_send_list(void *_dest)
484	{
485	struct audit_netlink_list *dest = _dest;
486	int pid = dest->pid;
487	struct sk_buff *skb;
488
489	/* wait for parent to finish and send an ACK */
490	mutex_lock(&audit_cmd_mutex);
491	mutex_unlock(&audit_cmd_mutex);
492
493	while ((skb = __skb_dequeue(&dest->q)) != NULL)
494	netlink_unicast(audit_sock, skb, pid, 0);
495
496	kfree(dest);
497
498	return 0;
499	}
500
501	struct sk_buff *audit_make_reply(int pid, int seq, int type, int done,
502	int multi, const void *payload, int size)
503	{
504	struct sk_buff *skb;
505	struct nlmsghdr *nlh;
506	void *data;
507	int flags = multi ? NLM_F_MULTI : 0;
508	int t = done ? NLMSG_DONE : type;
509
510	skb = nlmsg_new(size, GFP_KERNEL);
511	if (!skb)
512	return NULL;
513
514	nlh = NLMSG_NEW(skb, pid, seq, t, size, flags);
515	data = NLMSG_DATA(nlh);
516	memcpy(data, payload, size);
517	return skb;
518
519	nlmsg_failure: /* Used by NLMSG_NEW */
520	if (skb)
521	kfree_skb(skb);
522	return NULL;
523	}
524
525	static int audit_send_reply_thread(void *arg)
526	{
527	struct audit_reply reply = (struct audit_reply )arg;
528
529	mutex_lock(&audit_cmd_mutex);
530	mutex_unlock(&audit_cmd_mutex);
531
532	/* Ignore failure. It'll only happen if the sender goes away,
533	because our timeout is set to infinite. */
534	netlink_unicast(audit_sock, reply->skb, reply->pid, 0);
535	kfree(reply);
536	return 0;
537	}
538	/**
539	* audit_send_reply - send an audit reply message via netlink
540	* @pid: process id to send reply to
541	* @seq: sequence number
542	* @type: audit message type
543	* @done: done (last) flag
544	* @multi: multi-part message flag
545	* @payload: payload data
546	* @size: payload size
547	*
548	* Allocates an skb, builds the netlink message, and sends it to the pid.
549	* No failure notifications.
550	*/
551	static void audit_send_reply(int pid, int seq, int type, int done, int multi,
552	const void *payload, int size)
553	{
554	struct sk_buff *skb;
555	struct task_struct *tsk;
556	struct audit_reply *reply = kmalloc(sizeof(struct audit_reply),
557	GFP_KERNEL);
558
559	if (!reply)
560	return;
561
562	skb = audit_make_reply(pid, seq, type, done, multi, payload, size);
563	if (!skb)
564	goto out;
565
566	reply->pid = pid;
567	reply->skb = skb;
568
569	tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
570	if (!IS_ERR(tsk))
571	return;
572	kfree_skb(skb);
573	out:
574	kfree(reply);
575	}
576
577	/*
578	* Check for appropriate CAP_AUDIT_ capabilities on incoming audit
579	* control messages.
580	*/
581	static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
582	{
583	int err = 0;
584
585	switch (msg_type) {
586	case AUDIT_GET:
587	case AUDIT_LIST:
588	case AUDIT_LIST_RULES:
589	case AUDIT_SET:
590	case AUDIT_ADD:
591	case AUDIT_ADD_RULE:
592	case AUDIT_DEL:
593	case AUDIT_DEL_RULE:
594	case AUDIT_SIGNAL_INFO:
595	case AUDIT_TTY_GET:
596	case AUDIT_TTY_SET:
597	case AUDIT_TRIM:
598	case AUDIT_MAKE_EQUIV:
599	if (security_netlink_recv(skb, CAP_AUDIT_CONTROL))
600	err = -EPERM;
601	break;
602	case AUDIT_USER:
603	case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
604	case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
605	if (security_netlink_recv(skb, CAP_AUDIT_WRITE))
606	err = -EPERM;
607	break;
608	default: /* bad msg */
609	err = -EINVAL;
610	}
611
612	return err;
613	}
614
615	static int audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type,
616	u32 pid, u32 uid, uid_t auid, u32 ses,
617	u32 sid)
618	{
619	int rc = 0;
620	char *ctx = NULL;
621	u32 len;
622
623	if (!audit_enabled) {
624	*ab = NULL;
625	return rc;
626	}
627
628	*ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
629	audit_log_format(*ab, "user pid=%d uid=%u auid=%u ses=%u",
630	pid, uid, auid, ses);
631	if (sid) {
632	rc = security_secid_to_secctx(sid, &ctx, &len);
633	if (rc)
634	audit_log_format(*ab, " ssid=%u", sid);
635	else {
636	audit_log_format(*ab, " subj=%s", ctx);
637	security_release_secctx(ctx, len);
638	}
639	}
640
641	return rc;
642	}
643
644	static int audit_receive_msg(struct sk_buff skb, struct nlmsghdr nlh)
645	{
646	u32 uid, pid, seq, sid;
647	void *data;
648	struct audit_status *status_get, status_set;
649	int err;
650	struct audit_buffer *ab;
651	u16 msg_type = nlh->nlmsg_type;
652	uid_t loginuid; /* loginuid of sender */
653	u32 sessionid;
654	struct audit_sig_info *sig_data;
655	char *ctx = NULL;
656	u32 len;
657
658	err = audit_netlink_ok(skb, msg_type);
659	if (err)
660	return err;
661
662	/* As soon as there's any sign of userspace auditd,
663	* start kauditd to talk to it */
664	if (!kauditd_task)
665	kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
666	if (IS_ERR(kauditd_task)) {
667	err = PTR_ERR(kauditd_task);
668	kauditd_task = NULL;
669	return err;
670	}
671
672	pid = NETLINK_CREDS(skb)->pid;
673	uid = NETLINK_CREDS(skb)->uid;
674	loginuid = NETLINK_CB(skb).loginuid;
675	sessionid = NETLINK_CB(skb).sessionid;
676	sid = NETLINK_CB(skb).sid;
677	seq = nlh->nlmsg_seq;
678	data = NLMSG_DATA(nlh);
679
680	switch (msg_type) {
681	case AUDIT_GET:
682	status_set.enabled = audit_enabled;
683	status_set.failure = audit_failure;
684	status_set.pid = audit_pid;
685	status_set.rate_limit = audit_rate_limit;
686	status_set.backlog_limit = audit_backlog_limit;
687	status_set.lost = atomic_read(&audit_lost);
688	status_set.backlog = skb_queue_len(&audit_skb_queue);
689	audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_GET, 0, 0,
690	&status_set, sizeof(status_set));
691	break;
692	case AUDIT_SET:
693	if (nlh->nlmsg_len < sizeof(struct audit_status))
694	return -EINVAL;
695	status_get = (struct audit_status *)data;
696	if (status_get->mask & AUDIT_STATUS_ENABLED) {
697	err = audit_set_enabled(status_get->enabled,
698	loginuid, sessionid, sid);
699	if (err < 0)
700	return err;
701	}
702	if (status_get->mask & AUDIT_STATUS_FAILURE) {
703	err = audit_set_failure(status_get->failure,
704	loginuid, sessionid, sid);
705	if (err < 0)
706	return err;
707	}
708	if (status_get->mask & AUDIT_STATUS_PID) {
709	int new_pid = status_get->pid;
710
711	if (audit_enabled != AUDIT_OFF)
712	audit_log_config_change("audit_pid", new_pid,
713	audit_pid, loginuid,
714	sessionid, sid, 1);
715
716	audit_pid = new_pid;
717	audit_nlk_pid = NETLINK_CB(skb).pid;
718	}
719	if (status_get->mask & AUDIT_STATUS_RATE_LIMIT) {
720	err = audit_set_rate_limit(status_get->rate_limit,
721	loginuid, sessionid, sid);
722	if (err < 0)
723	return err;
724	}
725	if (status_get->mask & AUDIT_STATUS_BACKLOG_LIMIT)
726	err = audit_set_backlog_limit(status_get->backlog_limit,
727	loginuid, sessionid, sid);
728	break;
729	case AUDIT_USER:
730	case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
731	case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
732	if (!audit_enabled && msg_type != AUDIT_USER_AVC)
733	return 0;
734
735	err = audit_filter_user(&NETLINK_CB(skb));
736	if (err == 1) {
737	err = 0;
738	if (msg_type == AUDIT_USER_TTY) {
739	err = audit_prepare_user_tty(pid, loginuid,
740	sessionid);
741	if (err)
742	break;
743	}
744	audit_log_common_recv_msg(&ab, msg_type, pid, uid,
745	loginuid, sessionid, sid);
746
747	if (msg_type != AUDIT_USER_TTY)
748	audit_log_format(ab, " msg='%.1024s'",
749	(char *)data);
750	else {
751	int size;
752
753	audit_log_format(ab, " msg=");
754	size = nlmsg_len(nlh);
755	if (size > 0 &&
756	((unsigned char *)data)[size - 1] == '\0')
757	size--;
758	audit_log_n_untrustedstring(ab, data, size);
759	}
760	audit_set_pid(ab, pid);
761	audit_log_end(ab);
762	}
763	break;
764	case AUDIT_ADD:
765	case AUDIT_DEL:
766	if (nlmsg_len(nlh) < sizeof(struct audit_rule))
767	return -EINVAL;
768	if (audit_enabled == AUDIT_LOCKED) {
769	audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
770	uid, loginuid, sessionid, sid);
771
772	audit_log_format(ab, " audit_enabled=%d res=0",
773	audit_enabled);
774	audit_log_end(ab);
775	return -EPERM;
776	}
777	/* fallthrough */
778	case AUDIT_LIST:
779	err = audit_receive_filter(msg_type, NETLINK_CB(skb).pid,
780	uid, seq, data, nlmsg_len(nlh),
781	loginuid, sessionid, sid);
782	break;
783	case AUDIT_ADD_RULE:
784	case AUDIT_DEL_RULE:
785	if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
786	return -EINVAL;
787	if (audit_enabled == AUDIT_LOCKED) {
788	audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
789	uid, loginuid, sessionid, sid);
790
791	audit_log_format(ab, " audit_enabled=%d res=0",
792	audit_enabled);
793	audit_log_end(ab);
794	return -EPERM;
795	}
796	/* fallthrough */
797	case AUDIT_LIST_RULES:
798	err = audit_receive_filter(msg_type, NETLINK_CB(skb).pid,
799	uid, seq, data, nlmsg_len(nlh),
800	loginuid, sessionid, sid);
801	break;
802	case AUDIT_TRIM:
803	audit_trim_trees();
804
805	audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
806	uid, loginuid, sessionid, sid);
807
808	audit_log_format(ab, " op=trim res=1");
809	audit_log_end(ab);
810	break;
811	case AUDIT_MAKE_EQUIV: {
812	void *bufp = data;
813	u32 sizes[2];
814	size_t msglen = nlmsg_len(nlh);
815	char old, new;
816
817	err = -EINVAL;
818	if (msglen < 2 * sizeof(u32))
819	break;
820	memcpy(sizes, bufp, 2 * sizeof(u32));
821	bufp += 2 * sizeof(u32);
822	msglen -= 2 * sizeof(u32);
823	old = audit_unpack_string(&bufp, &msglen, sizes[0]);
824	if (IS_ERR(old)) {
825	err = PTR_ERR(old);
826	break;
827	}
828	new = audit_unpack_string(&bufp, &msglen, sizes[1]);
829	if (IS_ERR(new)) {
830	err = PTR_ERR(new);
831	kfree(old);
832	break;
833	}
834	/* OK, here comes... */
835	err = audit_tag_tree(old, new);
836
837	audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
838	uid, loginuid, sessionid, sid);
839
840	audit_log_format(ab, " op=make_equiv old=");
841	audit_log_untrustedstring(ab, old);
842	audit_log_format(ab, " new=");
843	audit_log_untrustedstring(ab, new);
844	audit_log_format(ab, " res=%d", !err);
845	audit_log_end(ab);
846	kfree(old);
847	kfree(new);
848	break;
849	}
850	case AUDIT_SIGNAL_INFO:
851	len = 0;
852	if (audit_sig_sid) {
853	err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
854	if (err)
855	return err;
856	}
857	sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
858	if (!sig_data) {
859	if (audit_sig_sid)
860	security_release_secctx(ctx, len);
861	return -ENOMEM;
862	}
863	sig_data->uid = audit_sig_uid;
864	sig_data->pid = audit_sig_pid;
865	if (audit_sig_sid) {
866	memcpy(sig_data->ctx, ctx, len);
867	security_release_secctx(ctx, len);
868	}
869	audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_SIGNAL_INFO,
870	0, 0, sig_data, sizeof(*sig_data) + len);
871	kfree(sig_data);
872	break;
873	case AUDIT_TTY_GET: {
874	struct audit_tty_status s;
875	struct task_struct *tsk;
876	unsigned long flags;
877
878	rcu_read_lock();
879	tsk = find_task_by_vpid(pid);
880	if (tsk && lock_task_sighand(tsk, &flags)) {
881	s.enabled = tsk->signal->audit_tty != 0;
882	unlock_task_sighand(tsk, &flags);
883	} else
884	err = -ESRCH;
885	rcu_read_unlock();
886
887	if (!err)
888	audit_send_reply(NETLINK_CB(skb).pid, seq,
889	AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
890	break;
891	}
892	case AUDIT_TTY_SET: {
893	struct audit_tty_status *s;
894	struct task_struct *tsk;
895	unsigned long flags;
896
897	if (nlh->nlmsg_len < sizeof(struct audit_tty_status))
898	return -EINVAL;
899	s = data;
900	if (s->enabled != 0 && s->enabled != 1)
901	return -EINVAL;
902	rcu_read_lock();
903	tsk = find_task_by_vpid(pid);
904	if (tsk && lock_task_sighand(tsk, &flags)) {
905	tsk->signal->audit_tty = s->enabled != 0;
906	unlock_task_sighand(tsk, &flags);
907	} else
908	err = -ESRCH;
909	rcu_read_unlock();
910	break;
911	}
912	default:
913	err = -EINVAL;
914	break;
915	}
916
917	return err < 0 ? err : 0;
918	}
919
920	/*
921	* Get message from skb. Each message is processed by audit_receive_msg.
922	* Malformed skbs with wrong length are discarded silently.
923	*/
924	static void audit_receive_skb(struct sk_buff *skb)
925	{
926	struct nlmsghdr *nlh;
927	/*
928	* len MUST be signed for NLMSG_NEXT to be able to dec it below 0
929	* if the nlmsg_len was not aligned
930	*/
931	int len;
932	int err;
933
934	nlh = nlmsg_hdr(skb);
935	len = skb->len;
936
937	while (NLMSG_OK(nlh, len)) {
938	err = audit_receive_msg(skb, nlh);
939	/* if err or if this message says it wants a response */
940	if (err \|\| (nlh->nlmsg_flags & NLM_F_ACK))
941	netlink_ack(skb, nlh, err);
942
943	nlh = NLMSG_NEXT(nlh, len);
944	}
945	}
946
947	/* Receive messages from netlink socket. */
948	static void audit_receive(struct sk_buff *skb)
949	{
950	mutex_lock(&audit_cmd_mutex);
951	audit_receive_skb(skb);
952	mutex_unlock(&audit_cmd_mutex);
953	}
954
955	/* Initialize audit support at boot time. */
956	static int __init audit_init(void)
957	{
958	int i;
959
960	if (audit_initialized == AUDIT_DISABLED)
961	return 0;
962
963	printk(KERN_INFO "audit: initializing netlink socket (%s)\n",
964	audit_default ? "enabled" : "disabled");
965	audit_sock = netlink_kernel_create(&init_net, NETLINK_AUDIT, 0,
966	audit_receive, NULL, THIS_MODULE);
967	if (!audit_sock)
968	audit_panic("cannot initialize netlink socket");
969	else
970	audit_sock->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
971
972	skb_queue_head_init(&audit_skb_queue);
973	skb_queue_head_init(&audit_skb_hold_queue);
974	audit_initialized = AUDIT_INITIALIZED;
975	audit_enabled = audit_default;
976	audit_ever_enabled \|= !!audit_default;
977
978	audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized");
979
980	for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
981	INIT_LIST_HEAD(&audit_inode_hash[i]);
982
983	return 0;
984	}
985	__initcall(audit_init);
986
987	/* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
988	static int __init audit_enable(char *str)
989	{
990	audit_default = !!simple_strtol(str, NULL, 0);
991	if (!audit_default)
992	audit_initialized = AUDIT_DISABLED;
993
994	printk(KERN_INFO "audit: %s", audit_default ? "enabled" : "disabled");
995
996	if (audit_initialized == AUDIT_INITIALIZED) {
997	audit_enabled = audit_default;
998	audit_ever_enabled \|= !!audit_default;
999	} else if (audit_initialized == AUDIT_UNINITIALIZED) {
1000	printk(" (after initialization)");
1001	} else {
1002	printk(" (until reboot)");
1003	}
1004	printk("\n");
1005
1006	return 1;
1007	}
1008
1009	__setup("audit=", audit_enable);
1010
1011	static void audit_buffer_free(struct audit_buffer *ab)
1012	{
1013	unsigned long flags;
1014
1015	if (!ab)
1016	return;
1017
1018	if (ab->skb)
1019	kfree_skb(ab->skb);
1020
1021	spin_lock_irqsave(&audit_freelist_lock, flags);
1022	if (audit_freelist_count > AUDIT_MAXFREE)
1023	kfree(ab);
1024	else {
1025	audit_freelist_count++;
1026	list_add(&ab->list, &audit_freelist);
1027	}
1028	spin_unlock_irqrestore(&audit_freelist_lock, flags);
1029	}
1030
1031	static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx,
1032	gfp_t gfp_mask, int type)
1033	{
1034	unsigned long flags;
1035	struct audit_buffer *ab = NULL;
1036	struct nlmsghdr *nlh;
1037
1038	spin_lock_irqsave(&audit_freelist_lock, flags);
1039	if (!list_empty(&audit_freelist)) {
1040	ab = list_entry(audit_freelist.next,
1041	struct audit_buffer, list);
1042	list_del(&ab->list);
1043	--audit_freelist_count;
1044	}
1045	spin_unlock_irqrestore(&audit_freelist_lock, flags);
1046
1047	if (!ab) {
1048	ab = kmalloc(sizeof(*ab), gfp_mask);
1049	if (!ab)
1050	goto err;
1051	}
1052
1053	ab->ctx = ctx;
1054	ab->gfp_mask = gfp_mask;
1055
1056	ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
1057	if (!ab->skb)
1058	goto nlmsg_failure;
1059
1060	nlh = NLMSG_NEW(ab->skb, 0, 0, type, 0, 0);
1061
1062	return ab;
1063
1064	nlmsg_failure: /* Used by NLMSG_NEW */
1065	kfree_skb(ab->skb);
1066	ab->skb = NULL;
1067	err:
1068	audit_buffer_free(ab);
1069	return NULL;
1070	}
1071
1072	/**
1073	* audit_serial - compute a serial number for the audit record
1074	*
1075	* Compute a serial number for the audit record. Audit records are
1076	* written to user-space as soon as they are generated, so a complete
1077	* audit record may be written in several pieces. The timestamp of the
1078	* record and this serial number are used by the user-space tools to
1079	* determine which pieces belong to the same audit record. The
1080	* (timestamp,serial) tuple is unique for each syscall and is live from
1081	* syscall entry to syscall exit.
1082	*
1083	* NOTE: Another possibility is to store the formatted records off the
1084	* audit context (for those records that have a context), and emit them
1085	* all at syscall exit. However, this could delay the reporting of
1086	* significant errors until syscall exit (or never, if the system
1087	* halts).
1088	*/
1089	unsigned int audit_serial(void)
1090	{
1091	static DEFINE_SPINLOCK(serial_lock);
1092	static unsigned int serial = 0;
1093
1094	unsigned long flags;
1095	unsigned int ret;
1096
1097	spin_lock_irqsave(&serial_lock, flags);
1098	do {
1099	ret = ++serial;
1100	} while (unlikely(!ret));
1101	spin_unlock_irqrestore(&serial_lock, flags);
1102
1103	return ret;
1104	}
1105
1106	static inline void audit_get_stamp(struct audit_context *ctx,
1107	struct timespec t, unsigned int serial)
1108	{
1109	if (!ctx \|\| !auditsc_get_stamp(ctx, t, serial)) {
1110	*t = CURRENT_TIME;
1111	*serial = audit_serial();
1112	}
1113	}
1114
1115	/* Obtain an audit buffer. This routine does locking to obtain the
1116	* audit buffer, but then no locking is required for calls to
1117	* audit_log_*format. If the tsk is a task that is currently in a
1118	* syscall, then the syscall is marked as auditable and an audit record
1119	* will be written at syscall exit. If there is no associated task, tsk
1120	* should be NULL. */
1121
1122	/**
1123	* audit_log_start - obtain an audit buffer
1124	* @ctx: audit_context (may be NULL)
1125	* @gfp_mask: type of allocation
1126	* @type: audit message type
1127	*
1128	* Returns audit_buffer pointer on success or NULL on error.
1129	*
1130	* Obtain an audit buffer. This routine does locking to obtain the
1131	* audit buffer, but then no locking is required for calls to
1132	* audit_log_*format. If the task (ctx) is a task that is currently in a
1133	* syscall, then the syscall is marked as auditable and an audit record
1134	* will be written at syscall exit. If there is no associated task, then
1135	* task context (ctx) should be NULL.
1136	*/
1137	struct audit_buffer audit_log_start(struct audit_context ctx, gfp_t gfp_mask,
1138	int type)
1139	{
1140	struct audit_buffer *ab = NULL;
1141	struct timespec t;
1142	unsigned int uninitialized_var(serial);
1143	int reserve;
1144	unsigned long timeout_start = jiffies;
1145
1146	if (audit_initialized != AUDIT_INITIALIZED)
1147	return NULL;
1148
1149	if (unlikely(audit_filter_type(type)))
1150	return NULL;
1151
1152	if (gfp_mask & __GFP_WAIT)
1153	reserve = 0;
1154	else
1155	reserve = 5; /* Allow atomic callers to go up to five
1156	entries over the normal backlog limit */
1157
1158	while (audit_backlog_limit
1159	&& skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) {
1160	if (gfp_mask & __GFP_WAIT && audit_backlog_wait_time
1161	&& time_before(jiffies, timeout_start + audit_backlog_wait_time)) {
1162
1163	/* Wait for auditd to drain the queue a little */
1164	DECLARE_WAITQUEUE(wait, current);
1165	set_current_state(TASK_INTERRUPTIBLE);
1166	add_wait_queue(&audit_backlog_wait, &wait);
1167
1168	if (audit_backlog_limit &&
1169	skb_queue_len(&audit_skb_queue) > audit_backlog_limit)
1170	schedule_timeout(timeout_start + audit_backlog_wait_time - jiffies);
1171
1172	__set_current_state(TASK_RUNNING);
1173	remove_wait_queue(&audit_backlog_wait, &wait);
1174	continue;
1175	}
1176	if (audit_rate_check() && printk_ratelimit())
1177	printk(KERN_WARNING
1178	"audit: audit_backlog=%d > "
1179	"audit_backlog_limit=%d\n",
1180	skb_queue_len(&audit_skb_queue),
1181	audit_backlog_limit);
1182	audit_log_lost("backlog limit exceeded");
1183	audit_backlog_wait_time = audit_backlog_wait_overflow;
1184	wake_up(&audit_backlog_wait);
1185	return NULL;
1186	}
1187
1188	ab = audit_buffer_alloc(ctx, gfp_mask, type);
1189	if (!ab) {
1190	audit_log_lost("out of memory in audit_log_start");
1191	return NULL;
1192	}
1193
1194	audit_get_stamp(ab->ctx, &t, &serial);
1195
1196	audit_log_format(ab, "audit(%lu.%03lu:%u): ",
1197	t.tv_sec, t.tv_nsec/1000000, serial);
1198	return ab;
1199	}
1200
1201	/**
1202	* audit_expand - expand skb in the audit buffer
1203	* @ab: audit_buffer
1204	* @extra: space to add at tail of the skb
1205	*
1206	* Returns 0 (no space) on failed expansion, or available space if
1207	* successful.
1208	*/
1209	static inline int audit_expand(struct audit_buffer *ab, int extra)
1210	{
1211	struct sk_buff *skb = ab->skb;
1212	int oldtail = skb_tailroom(skb);
1213	int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1214	int newtail = skb_tailroom(skb);
1215
1216	if (ret < 0) {
1217	audit_log_lost("out of memory in audit_expand");
1218	return 0;
1219	}
1220
1221	skb->truesize += newtail - oldtail;
1222	return newtail;
1223	}
1224
1225	/*
1226	* Format an audit message into the audit buffer. If there isn't enough
1227	* room in the audit buffer, more room will be allocated and vsnprint
1228	* will be called a second time. Currently, we assume that a printk
1229	* can't format message larger than 1024 bytes, so we don't either.
1230	*/
1231	static void audit_log_vformat(struct audit_buffer ab, const char fmt,
1232	va_list args)
1233	{
1234	int len, avail;
1235	struct sk_buff *skb;
1236	va_list args2;
1237
1238	if (!ab)
1239	return;
1240
1241	BUG_ON(!ab->skb);
1242	skb = ab->skb;
1243	avail = skb_tailroom(skb);
1244	if (avail == 0) {
1245	avail = audit_expand(ab, AUDIT_BUFSIZ);
1246	if (!avail)
1247	goto out;
1248	}
1249	va_copy(args2, args);
1250	len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1251	if (len >= avail) {
1252	/* The printk buffer is 1024 bytes long, so if we get
1253	* here and AUDIT_BUFSIZ is at least 1024, then we can
1254	* log everything that printk could have logged. */
1255	avail = audit_expand(ab,
1256	max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1257	if (!avail)
1258	goto out;
1259	len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1260	}
1261	va_end(args2);
1262	if (len > 0)
1263	skb_put(skb, len);
1264	out:
1265	return;
1266	}
1267
1268	/**
1269	* audit_log_format - format a message into the audit buffer.
1270	* @ab: audit_buffer
1271	* @fmt: format string
1272	* @...: optional parameters matching @fmt string
1273	*
1274	* All the work is done in audit_log_vformat.
1275	*/
1276	void audit_log_format(struct audit_buffer ab, const char fmt, ...)
1277	{
1278	va_list args;
1279
1280	if (!ab)
1281	return;
1282	va_start(args, fmt);
1283	audit_log_vformat(ab, fmt, args);
1284	va_end(args);
1285	}
1286
1287	/**
1288	* audit_log_hex - convert a buffer to hex and append it to the audit skb
1289	* @ab: the audit_buffer
1290	* @buf: buffer to convert to hex
1291	* @len: length of @buf to be converted
1292	*
1293	* No return value; failure to expand is silently ignored.
1294	*
1295	* This function will take the passed buf and convert it into a string of
1296	* ascii hex digits. The new string is placed onto the skb.
1297	*/
1298	void audit_log_n_hex(struct audit_buffer ab, const unsigned char buf,
1299	size_t len)
1300	{
1301	int i, avail, new_len;
1302	unsigned char *ptr;
1303	struct sk_buff *skb;
1304	static const unsigned char *hex = "0123456789ABCDEF";
1305
1306	if (!ab)
1307	return;
1308
1309	BUG_ON(!ab->skb);
1310	skb = ab->skb;
1311	avail = skb_tailroom(skb);
1312	new_len = len<<1;
1313	if (new_len >= avail) {
1314	/* Round the buffer request up to the next multiple */
1315	new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1316	avail = audit_expand(ab, new_len);
1317	if (!avail)
1318	return;
1319	}
1320
1321	ptr = skb_tail_pointer(skb);
1322	for (i=0; i<len; i++) {
1323	ptr++ = hex[(buf[i] & 0xF0)>>4]; / Upper nibble */
1324	ptr++ = hex[buf[i] & 0x0F]; / Lower nibble */
1325	}
1326	*ptr = 0;
1327	skb_put(skb, len << 1); /* new string is twice the old string */
1328	}
1329
1330	/*
1331	* Format a string of no more than slen characters into the audit buffer,
1332	* enclosed in quote marks.
1333	*/
1334	void audit_log_n_string(struct audit_buffer ab, const char string,
1335	size_t slen)
1336	{
1337	int avail, new_len;
1338	unsigned char *ptr;
1339	struct sk_buff *skb;
1340
1341	if (!ab)
1342	return;
1343
1344	BUG_ON(!ab->skb);
1345	skb = ab->skb;
1346	avail = skb_tailroom(skb);
1347	new_len = slen + 3; /* enclosing quotes + null terminator */
1348	if (new_len > avail) {
1349	avail = audit_expand(ab, new_len);
1350	if (!avail)
1351	return;
1352	}
1353	ptr = skb_tail_pointer(skb);
1354	*ptr++ = '"';
1355	memcpy(ptr, string, slen);
1356	ptr += slen;
1357	*ptr++ = '"';
1358	*ptr = 0;
1359	skb_put(skb, slen + 2); /* don't include null terminator */
1360	}
1361
1362	/**
1363	* audit_string_contains_control - does a string need to be logged in hex
1364	* @string: string to be checked
1365	* @len: max length of the string to check
1366	*/
1367	int audit_string_contains_control(const char *string, size_t len)
1368	{
1369	const unsigned char *p;
1370	for (p = string; p < (const unsigned char *)string + len; p++) {
1371	if (p == '"' \|\| p < 0x21 \|\| *p > 0x7e)
1372	return 1;
1373	}
1374	return 0;
1375	}
1376
1377	/**
1378	* audit_log_n_untrustedstring - log a string that may contain random characters
1379	* @ab: audit_buffer
1380	* @len: length of string (not including trailing null)
1381	* @string: string to be logged
1382	*
1383	* This code will escape a string that is passed to it if the string
1384	* contains a control character, unprintable character, double quote mark,
1385	* or a space. Unescaped strings will start and end with a double quote mark.
1386	* Strings that are escaped are printed in hex (2 digits per char).
1387	*
1388	* The caller specifies the number of characters in the string to log, which may
1389	* or may not be the entire string.
1390	*/
1391	void audit_log_n_untrustedstring(struct audit_buffer ab, const char string,
1392	size_t len)
1393	{
1394	if (audit_string_contains_control(string, len))
1395	audit_log_n_hex(ab, string, len);
1396	else
1397	audit_log_n_string(ab, string, len);
1398	}
1399
1400	/**
1401	* audit_log_untrustedstring - log a string that may contain random characters
1402	* @ab: audit_buffer
1403	* @string: string to be logged
1404	*
1405	* Same as audit_log_n_untrustedstring(), except that strlen is used to
1406	* determine string length.
1407	*/
1408	void audit_log_untrustedstring(struct audit_buffer ab, const char string)
1409	{
1410	audit_log_n_untrustedstring(ab, string, strlen(string));
1411	}
1412
1413	/* This is a helper-function to print the escaped d_path */
1414	void audit_log_d_path(struct audit_buffer ab, const char prefix,
1415	struct path *path)
1416	{
1417	char p, pathname;
1418
1419	if (prefix)
1420	audit_log_format(ab, " %s", prefix);
1421
1422	/* We will allow 11 spaces for ' (deleted)' to be appended */
1423	pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
1424	if (!pathname) {
1425	audit_log_string(ab, "<no_memory>");
1426	return;
1427	}
1428	p = d_path(path, pathname, PATH_MAX+11);
1429	if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
1430	/* FIXME: can we save some information here? */
1431	audit_log_string(ab, "<too_long>");
1432	} else
1433	audit_log_untrustedstring(ab, p);
1434	kfree(pathname);
1435	}
1436
1437	void audit_log_key(struct audit_buffer ab, char key)
1438	{
1439	audit_log_format(ab, " key=");
1440	if (key)
1441	audit_log_untrustedstring(ab, key);
1442	else
1443	audit_log_format(ab, "(null)");
1444	}
1445
1446	/**
1447	* audit_log_end - end one audit record
1448	* @ab: the audit_buffer
1449	*
1450	* The netlink_* functions cannot be called inside an irq context, so
1451	* the audit buffer is placed on a queue and a tasklet is scheduled to
1452	* remove them from the queue outside the irq context. May be called in
1453	* any context.
1454	*/
1455	void audit_log_end(struct audit_buffer *ab)
1456	{
1457	if (!ab)
1458	return;
1459	if (!audit_rate_check()) {
1460	audit_log_lost("rate limit exceeded");
1461	} else {
1462	struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
1463	nlh->nlmsg_len = ab->skb->len - NLMSG_SPACE(0);
1464
1465	if (audit_pid) {
1466	skb_queue_tail(&audit_skb_queue, ab->skb);
1467	wake_up_interruptible(&kauditd_wait);
1468	} else {
1469	audit_printk_skb(ab->skb);
1470	}
1471	ab->skb = NULL;
1472	}
1473	audit_buffer_free(ab);
1474	}
1475
1476	/**
1477	* audit_log - Log an audit record
1478	* @ctx: audit context
1479	* @gfp_mask: type of allocation
1480	* @type: audit message type
1481	* @fmt: format string to use
1482	* @...: variable parameters matching the format string
1483	*
1484	* This is a convenience function that calls audit_log_start,
1485	* audit_log_vformat, and audit_log_end. It may be called
1486	* in any context.
1487	*/
1488	void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
1489	const char *fmt, ...)
1490	{
1491	struct audit_buffer *ab;
1492	va_list args;
1493
1494	ab = audit_log_start(ctx, gfp_mask, type);
1495	if (ab) {
1496	va_start(args, fmt);
1497	audit_log_vformat(ab, fmt, args);
1498	va_end(args);
1499	audit_log_end(ab);
1500	}
1501	}
1502
1503	EXPORT_SYMBOL(audit_log_start);
1504	EXPORT_SYMBOL(audit_log_end);
1505	EXPORT_SYMBOL(audit_log_format);
1506	EXPORT_SYMBOL(audit_log);
1507

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