linux - kernel/audit.c

2845 lines · 74.3 KiB

1	// SPDX-License-Identifier: GPL-2.0-or-later
2	/* audit.c -- Auditing support
3	* Gateway between the kernel (e.g., selinux) and the user-space audit daemon.
4	* System-call specific features have moved to auditsc.c
5	*
6	* Copyright 2003-2007 Red Hat Inc., Durham, North Carolina.
7	* All Rights Reserved.
8	*
9	* Written by Rickard E. (Rik) Faith <[email protected]>
10	*
11	* Goals: 1) Integrate fully with Security Modules.
12	* 2) Minimal run-time overhead:
13	* a) Minimal when syscall auditing is disabled (audit_enable=0).
14	* b) Small when syscall auditing is enabled and no audit record
15	* is generated (defer as much work as possible to record
16	* generation time):
17	* i) context is allocated,
18	* ii) names from getname are stored without a copy, and
19	* iii) inode information stored from path_lookup.
20	* 3) Ability to disable syscall auditing at boot time (audit=0).
21	* 4) Usable by other parts of the kernel (if audit_log* is called,
22	* then a syscall record will be generated automatically for the
23	* current syscall).
24	* 5) Netlink interface to user-space.
25	* 6) Support low-overhead kernel-based filtering to minimize the
26	* information that must be passed to user-space.
27	*
28	* Audit userspace, documentation, tests, and bug/issue trackers:
29	* https://github.com/linux-audit
30	*/
31
32	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
33
34	#include <linux/file.h>
35	#include <linux/hex.h>
36	#include <linux/init.h>
37	#include <linux/types.h>
38	#include <linux/atomic.h>
39	#include <linux/mm.h>
40	#include <linux/export.h>
41	#include <linux/slab.h>
42	#include <linux/err.h>
43	#include <linux/kthread.h>
44	#include <linux/kernel.h>
45	#include <linux/syscalls.h>
46	#include <linux/spinlock.h>
47	#include <linux/rcupdate.h>
48	#include <linux/mutex.h>
49	#include <linux/gfp.h>
50	#include <linux/pid.h>
51
52	#include <linux/audit.h>
53
54	#include <net/sock.h>
55	#include <net/netlink.h>
56	#include <linux/skbuff.h>
57	#include <linux/security.h>
58	#include <linux/lsm_hooks.h>
59	#include <linux/freezer.h>
60	#include <linux/pid_namespace.h>
61	#include <net/netns/generic.h>
62	#include <net/ip.h>
63	#include <net/ipv6.h>
64	#include <linux/sctp.h>
65
66	#include "audit.h"
67
68	/* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
69	* (Initialization happens after skb_init is called.) */
70	#define AUDIT_DISABLED -1
71	#define AUDIT_UNINITIALIZED 0
72	#define AUDIT_INITIALIZED 1
73	static int audit_initialized = AUDIT_UNINITIALIZED;
74
75	u32 audit_enabled = AUDIT_OFF;
76	bool audit_ever_enabled = !!AUDIT_OFF;
77
78	EXPORT_SYMBOL_GPL(audit_enabled);
79
80	/* Default state when kernel boots without any parameters. */
81	static u32 audit_default = AUDIT_OFF;
82
83	/* If auditing cannot proceed, audit_failure selects what happens. */
84	static u32 audit_failure = AUDIT_FAIL_PRINTK;
85
86	/* private audit network namespace index */
87	static unsigned int audit_net_id;
88
89	/* Number of modules that provide a security context.
90	List of lsms that provide a security context */
91	static u32 audit_subj_secctx_cnt;
92	static u32 audit_obj_secctx_cnt;
93	static const struct lsm_id *audit_subj_lsms[MAX_LSM_COUNT];
94	static const struct lsm_id *audit_obj_lsms[MAX_LSM_COUNT];
95
96	/**
97	* struct audit_net - audit private network namespace data
98	* @sk: communication socket
99	*/
100	struct audit_net {
101	struct sock *sk;
102	};
103
104	/**
105	* struct auditd_connection - kernel/auditd connection state
106	* @pid: auditd PID
107	* @portid: netlink portid
108	* @net: the associated network namespace
109	* @rcu: RCU head
110	*
111	* Description:
112	* This struct is RCU protected; you must either hold the RCU lock for reading
113	* or the associated spinlock for writing.
114	*/
115	struct auditd_connection {
116	struct pid *pid;
117	u32 portid;
118	struct net *net;
119	struct rcu_head rcu;
120	};
121	static struct auditd_connection __rcu *auditd_conn;
122	static DEFINE_SPINLOCK(auditd_conn_lock);
123
124	/* If audit_rate_limit is non-zero, limit the rate of sending audit records
125	* to that number per second. This prevents DoS attacks, but results in
126	* audit records being dropped. */
127	static u32 audit_rate_limit;
128
129	/* Number of outstanding audit_buffers allowed.
130	* When set to zero, this means unlimited. */
131	static u32 audit_backlog_limit = 64;
132	#define AUDIT_BACKLOG_WAIT_TIME (60 * HZ)
133	static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
134
135	/* The identity of the user shutting down the audit system. */
136	static kuid_t audit_sig_uid = INVALID_UID;
137	static pid_t audit_sig_pid = -1;
138	static struct lsm_prop audit_sig_lsm;
139
140	/* Records can be lost in several ways:
141	0) [suppressed in audit_alloc]
142	1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
143	2) out of memory in audit_log_move [alloc_skb]
144	3) suppressed due to audit_rate_limit
145	4) suppressed due to audit_backlog_limit
146	*/
147	static atomic_t audit_lost = ATOMIC_INIT(0);
148
149	/* Monotonically increasing sum of time the kernel has spent
150	* waiting while the backlog limit is exceeded.
151	*/
152	static atomic_t audit_backlog_wait_time_actual = ATOMIC_INIT(0);
153
154	/* Hash for inode-based rules */
155	struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
156
157	static struct kmem_cache *audit_buffer_cache;
158
159	/* queue msgs to send via kauditd_task */
160	static struct sk_buff_head audit_queue;
161	/* queue msgs due to temporary unicast send problems */
162	static struct sk_buff_head audit_retry_queue;
163	/* queue msgs waiting for new auditd connection */
164	static struct sk_buff_head audit_hold_queue;
165
166	/* queue servicing thread */
167	static struct task_struct *kauditd_task;
168	static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
169
170	/* waitqueue for callers who are blocked on the audit backlog */
171	static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
172
173	static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION,
174	.mask = -1,
175	.features = 0,
176	.lock = 0,};
177
178	static char *audit_feature_names[2] = {
179	"only_unset_loginuid",
180	"loginuid_immutable",
181	};
182
183	/**
184	* struct audit_ctl_mutex - serialize requests from userspace
185	* @lock: the mutex used for locking
186	* @owner: the task which owns the lock
187	*
188	* Description:
189	* This is the lock struct used to ensure we only process userspace requests
190	* in an orderly fashion. We can't simply use a mutex/lock here because we
191	* need to track lock ownership so we don't end up blocking the lock owner in
192	* audit_log_start() or similar.
193	*/
194	static struct audit_ctl_mutex {
195	struct mutex lock;
196	void *owner;
197	} audit_cmd_mutex;
198
199	/* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
200	* audit records. Since printk uses a 1024 byte buffer, this buffer
201	* should be at least that large. */
202	#define AUDIT_BUFSIZ 1024
203
204	/* The audit_buffer is used when formatting an audit record. The caller
205	* locks briefly to get the record off the freelist or to allocate the
206	* buffer, and locks briefly to send the buffer to the netlink layer or
207	* to place it on a transmit queue. Multiple audit_buffers can be in
208	* use simultaneously. */
209	struct audit_buffer {
210	struct sk_buff skb; / the skb for audit_log functions */
211	struct sk_buff_head skb_list; /* formatted skbs, ready to send */
212	struct audit_context ctx; / NULL or associated context */
213	struct audit_stamp stamp; /* audit stamp for these records */
214	gfp_t gfp_mask;
215	};
216
217	struct audit_reply {
218	__u32 portid;
219	struct net *net;
220	struct sk_buff *skb;
221	};
222
223	/**
224	* auditd_test_task - Check to see if a given task is an audit daemon
225	* @task: the task to check
226	*
227	* Description:
228	* Return 1 if the task is a registered audit daemon, 0 otherwise.
229	*/
230	int auditd_test_task(struct task_struct *task)
231	{
232	int rc;
233	struct auditd_connection *ac;
234
235	rcu_read_lock();
236	ac = rcu_dereference(auditd_conn);
237	rc = (ac && ac->pid == task_tgid(task) ? 1 : 0);
238	rcu_read_unlock();
239
240	return rc;
241	}
242
243	/**
244	* audit_ctl_lock - Take the audit control lock
245	*/
246	void audit_ctl_lock(void)
247	{
248	mutex_lock(&audit_cmd_mutex.lock);
249	audit_cmd_mutex.owner = current;
250	}
251
252	/**
253	* audit_ctl_unlock - Drop the audit control lock
254	*/
255	void audit_ctl_unlock(void)
256	{
257	audit_cmd_mutex.owner = NULL;
258	mutex_unlock(&audit_cmd_mutex.lock);
259	}
260
261	/**
262	* audit_ctl_owner_current - Test to see if the current task owns the lock
263	*
264	* Description:
265	* Return true if the current task owns the audit control lock, false if it
266	* doesn't own the lock.
267	*/
268	static bool audit_ctl_owner_current(void)
269	{
270	return (current == audit_cmd_mutex.owner);
271	}
272
273	/**
274	* auditd_pid_vnr - Return the auditd PID relative to the namespace
275	*
276	* Description:
277	* Returns the PID in relation to the namespace, 0 on failure.
278	*/
279	static pid_t auditd_pid_vnr(void)
280	{
281	pid_t pid;
282	const struct auditd_connection *ac;
283
284	rcu_read_lock();
285	ac = rcu_dereference(auditd_conn);
286	if (!ac \|\| !ac->pid)
287	pid = 0;
288	else
289	pid = pid_vnr(ac->pid);
290	rcu_read_unlock();
291
292	return pid;
293	}
294
295	/**
296	* audit_cfg_lsm - Identify a security module as providing a secctx.
297	* @lsmid: LSM identity
298	* @flags: which contexts are provided
299	*
300	* Description:
301	* Increments the count of the security modules providing a secctx.
302	* If the LSM id is already in the list leave it alone.
303	*/
304	void audit_cfg_lsm(const struct lsm_id *lsmid, int flags)
305	{
306	int i;
307
308	if (flags & AUDIT_CFG_LSM_SECCTX_SUBJECT) {
309	for (i = 0 ; i < audit_subj_secctx_cnt; i++)
310	if (audit_subj_lsms[i] == lsmid)
311	return;
312	audit_subj_lsms[audit_subj_secctx_cnt++] = lsmid;
313	}
314	if (flags & AUDIT_CFG_LSM_SECCTX_OBJECT) {
315	for (i = 0 ; i < audit_obj_secctx_cnt; i++)
316	if (audit_obj_lsms[i] == lsmid)
317	return;
318	audit_obj_lsms[audit_obj_secctx_cnt++] = lsmid;
319	}
320	}
321
322	/**
323	* audit_get_sk - Return the audit socket for the given network namespace
324	* @net: the destination network namespace
325	*
326	* Description:
327	* Returns the sock pointer if valid, NULL otherwise. The caller must ensure
328	* that a reference is held for the network namespace while the sock is in use.
329	*/
330	static struct sock audit_get_sk(const struct net net)
331	{
332	struct audit_net *aunet;
333
334	if (!net)
335	return NULL;
336
337	aunet = net_generic(net, audit_net_id);
338	return aunet->sk;
339	}
340
341	void audit_panic(const char *message)
342	{
343	switch (audit_failure) {
344	case AUDIT_FAIL_SILENT:
345	break;
346	case AUDIT_FAIL_PRINTK:
347	if (printk_ratelimit())
348	pr_err("%s\n", message);
349	break;
350	case AUDIT_FAIL_PANIC:
351	panic("audit: %s\n", message);
352	break;
353	}
354	}
355
356	static inline int audit_rate_check(void)
357	{
358	static unsigned long last_check;
359	static int messages;
360	static DEFINE_SPINLOCK(lock);
361	unsigned long flags;
362	unsigned long now;
363	int retval = 0;
364
365	if (!audit_rate_limit)
366	return 1;
367
368	spin_lock_irqsave(&lock, flags);
369	if (++messages < audit_rate_limit) {
370	retval = 1;
371	} else {
372	now = jiffies;
373	if (time_after(now, last_check + HZ)) {
374	last_check = now;
375	messages = 0;
376	retval = 1;
377	}
378	}
379	spin_unlock_irqrestore(&lock, flags);
380
381	return retval;
382	}
383
384	/**
385	* audit_log_lost - conditionally log lost audit message event
386	* @message: the message stating reason for lost audit message
387	*
388	* Emit at least 1 message per second, even if audit_rate_check is
389	* throttling.
390	* Always increment the lost messages counter.
391	*/
392	void audit_log_lost(const char *message)
393	{
394	static unsigned long last_msg;
395	static DEFINE_SPINLOCK(lock);
396	unsigned long flags;
397	unsigned long now;
398	int print;
399
400	atomic_inc(&audit_lost);
401
402	print = (audit_failure == AUDIT_FAIL_PANIC \|\| !audit_rate_limit);
403
404	if (!print) {
405	spin_lock_irqsave(&lock, flags);
406	now = jiffies;
407	if (time_after(now, last_msg + HZ)) {
408	print = 1;
409	last_msg = now;
410	}
411	spin_unlock_irqrestore(&lock, flags);
412	}
413
414	if (print) {
415	if (printk_ratelimit())
416	pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
417	atomic_read(&audit_lost),
418	audit_rate_limit,
419	audit_backlog_limit);
420	audit_panic(message);
421	}
422	}
423
424	static int audit_log_config_change(char *function_name, u32 new, u32 old,
425	int allow_changes)
426	{
427	struct audit_buffer *ab;
428	int rc = 0;
429
430	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
431	if (unlikely(!ab))
432	return rc;
433	audit_log_format(ab, "op=set %s=%u old=%u ", function_name, new, old);
434	audit_log_session_info(ab);
435	rc = audit_log_task_context(ab);
436	if (rc)
437	allow_changes = 0; /* Something weird, deny request */
438	audit_log_format(ab, " res=%d", allow_changes);
439	audit_log_end(ab);
440	return rc;
441	}
442
443	static int audit_do_config_change(char function_name, u32 to_change, u32 new)
444	{
445	int allow_changes, rc = 0;
446	u32 old = *to_change;
447
448	/* check if we are locked */
449	if (audit_enabled == AUDIT_LOCKED)
450	allow_changes = 0;
451	else
452	allow_changes = 1;
453
454	if (audit_enabled != AUDIT_OFF) {
455	rc = audit_log_config_change(function_name, new, old, allow_changes);
456	if (rc)
457	allow_changes = 0;
458	}
459
460	/* If we are allowed, make the change */
461	if (allow_changes == 1)
462	*to_change = new;
463	/* Not allowed, update reason */
464	else if (rc == 0)
465	rc = -EPERM;
466	return rc;
467	}
468
469	static int audit_set_rate_limit(u32 limit)
470	{
471	return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit);
472	}
473
474	static int audit_set_backlog_limit(u32 limit)
475	{
476	return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit);
477	}
478
479	static int audit_set_backlog_wait_time(u32 timeout)
480	{
481	return audit_do_config_change("audit_backlog_wait_time",
482	&audit_backlog_wait_time, timeout);
483	}
484
485	static int audit_set_enabled(u32 state)
486	{
487	int rc;
488	if (state > AUDIT_LOCKED)
489	return -EINVAL;
490
491	rc = audit_do_config_change("audit_enabled", &audit_enabled, state);
492	if (!rc)
493	audit_ever_enabled \|= !!state;
494
495	return rc;
496	}
497
498	static int audit_set_failure(u32 state)
499	{
500	if (state != AUDIT_FAIL_SILENT
501	&& state != AUDIT_FAIL_PRINTK
502	&& state != AUDIT_FAIL_PANIC)
503	return -EINVAL;
504
505	return audit_do_config_change("audit_failure", &audit_failure, state);
506	}
507
508	/**
509	* auditd_conn_free - RCU helper to release an auditd connection struct
510	* @rcu: RCU head
511	*
512	* Description:
513	* Drop any references inside the auditd connection tracking struct and free
514	* the memory.
515	*/
516	static void auditd_conn_free(struct rcu_head *rcu)
517	{
518	struct auditd_connection *ac;
519
520	ac = container_of(rcu, struct auditd_connection, rcu);
521	put_pid(ac->pid);
522	put_net(ac->net);
523	kfree(ac);
524	}
525
526	/**
527	* auditd_set - Set/Reset the auditd connection state
528	* @pid: auditd PID
529	* @portid: auditd netlink portid
530	* @net: auditd network namespace pointer
531	* @skb: the netlink command from the audit daemon
532	* @ack: netlink ack flag, cleared if ack'd here
533	*
534	* Description:
535	* This function will obtain and drop network namespace references as
536	* necessary. Returns zero on success, negative values on failure.
537	*/
538	static int auditd_set(struct pid pid, u32 portid, struct net net,
539	struct sk_buff skb, bool ack)
540	{
541	unsigned long flags;
542	struct auditd_connection ac_old, ac_new;
543	struct nlmsghdr *nlh;
544
545	if (!pid \|\| !net)
546	return -EINVAL;
547
548	ac_new = kzalloc_obj(*ac_new);
549	if (!ac_new)
550	return -ENOMEM;
551	ac_new->pid = get_pid(pid);
552	ac_new->portid = portid;
553	ac_new->net = get_net(net);
554
555	/* send the ack now to avoid a race with the queue backlog */
556	if (*ack) {
557	nlh = nlmsg_hdr(skb);
558	netlink_ack(skb, nlh, 0, NULL);
559	*ack = false;
560	}
561
562	spin_lock_irqsave(&auditd_conn_lock, flags);
563	ac_old = rcu_dereference_protected(auditd_conn,
564	lockdep_is_held(&auditd_conn_lock));
565	rcu_assign_pointer(auditd_conn, ac_new);
566	spin_unlock_irqrestore(&auditd_conn_lock, flags);
567
568	if (ac_old)
569	call_rcu(&ac_old->rcu, auditd_conn_free);
570
571	return 0;
572	}
573
574	/**
575	* kauditd_printk_skb - Print the audit record to the ring buffer
576	* @skb: audit record
577	*
578	* Whatever the reason, this packet may not make it to the auditd connection
579	* so write it via printk so the information isn't completely lost.
580	*/
581	static void kauditd_printk_skb(struct sk_buff *skb)
582	{
583	struct nlmsghdr *nlh = nlmsg_hdr(skb);
584	char *data = nlmsg_data(nlh);
585
586	if (nlh->nlmsg_type != AUDIT_EOE && printk_ratelimit())
587	pr_notice("type=%d %s\n", nlh->nlmsg_type, data);
588	}
589
590	/**
591	* kauditd_rehold_skb - Handle a audit record send failure in the hold queue
592	* @skb: audit record
593	* @error: error code (unused)
594	*
595	* Description:
596	* This should only be used by the kauditd_thread when it fails to flush the
597	* hold queue.
598	*/
599	static void kauditd_rehold_skb(struct sk_buff *skb, __always_unused int error)
600	{
601	/* put the record back in the queue */
602	skb_queue_tail(&audit_hold_queue, skb);
603	}
604
605	/**
606	* kauditd_hold_skb - Queue an audit record, waiting for auditd
607	* @skb: audit record
608	* @error: error code
609	*
610	* Description:
611	* Queue the audit record, waiting for an instance of auditd. When this
612	* function is called we haven't given up yet on sending the record, but things
613	* are not looking good. The first thing we want to do is try to write the
614	* record via printk and then see if we want to try and hold on to the record
615	* and queue it, if we have room. If we want to hold on to the record, but we
616	* don't have room, record a record lost message.
617	*/
618	static void kauditd_hold_skb(struct sk_buff *skb, int error)
619	{
620	/* at this point it is uncertain if we will ever send this to auditd so
621	* try to send the message via printk before we go any further */
622	kauditd_printk_skb(skb);
623
624	/* can we just silently drop the message? */
625	if (!audit_default)
626	goto drop;
627
628	/* the hold queue is only for when the daemon goes away completely,
629	* not -EAGAIN failures; if we are in a -EAGAIN state requeue the
630	* record on the retry queue unless it's full, in which case drop it
631	*/
632	if (error == -EAGAIN) {
633	if (!audit_backlog_limit \|\|
634	skb_queue_len(&audit_retry_queue) < audit_backlog_limit) {
635	skb_queue_tail(&audit_retry_queue, skb);
636	return;
637	}
638	audit_log_lost("kauditd retry queue overflow");
639	goto drop;
640	}
641
642	/* if we have room in the hold queue, queue the message */
643	if (!audit_backlog_limit \|\|
644	skb_queue_len(&audit_hold_queue) < audit_backlog_limit) {
645	skb_queue_tail(&audit_hold_queue, skb);
646	return;
647	}
648
649	/* we have no other options - drop the message */
650	audit_log_lost("kauditd hold queue overflow");
651	drop:
652	kfree_skb(skb);
653	}
654
655	/**
656	* kauditd_retry_skb - Queue an audit record, attempt to send again to auditd
657	* @skb: audit record
658	* @error: error code (unused)
659	*
660	* Description:
661	* Not as serious as kauditd_hold_skb() as we still have a connected auditd,
662	* but for some reason we are having problems sending it audit records so
663	* queue the given record and attempt to resend.
664	*/
665	static void kauditd_retry_skb(struct sk_buff *skb, __always_unused int error)
666	{
667	if (!audit_backlog_limit \|\|
668	skb_queue_len(&audit_retry_queue) < audit_backlog_limit) {
669	skb_queue_tail(&audit_retry_queue, skb);
670	return;
671	}
672
673	/* we have to drop the record, send it via printk as a last effort */
674	kauditd_printk_skb(skb);
675	audit_log_lost("kauditd retry queue overflow");
676	kfree_skb(skb);
677	}
678
679	/**
680	* auditd_reset - Disconnect the auditd connection
681	* @ac: auditd connection state
682	*
683	* Description:
684	* Break the auditd/kauditd connection and move all the queued records into the
685	* hold queue in case auditd reconnects. It is important to note that the @ac
686	* pointer should never be dereferenced inside this function as it may be NULL
687	* or invalid, you can only compare the memory address! If @ac is NULL then
688	* the connection will always be reset.
689	*/
690	static void auditd_reset(const struct auditd_connection *ac)
691	{
692	unsigned long flags;
693	struct sk_buff *skb;
694	struct auditd_connection *ac_old;
695
696	/* if it isn't already broken, break the connection */
697	spin_lock_irqsave(&auditd_conn_lock, flags);
698	ac_old = rcu_dereference_protected(auditd_conn,
699	lockdep_is_held(&auditd_conn_lock));
700	if (ac && ac != ac_old) {
701	/* someone already registered a new auditd connection */
702	spin_unlock_irqrestore(&auditd_conn_lock, flags);
703	return;
704	}
705	rcu_assign_pointer(auditd_conn, NULL);
706	spin_unlock_irqrestore(&auditd_conn_lock, flags);
707
708	if (ac_old)
709	call_rcu(&ac_old->rcu, auditd_conn_free);
710
711	/* flush the retry queue to the hold queue, but don't touch the main
712	* queue since we need to process that normally for multicast */
713	while ((skb = skb_dequeue(&audit_retry_queue)))
714	kauditd_hold_skb(skb, -ECONNREFUSED);
715	}
716
717	/**
718	* auditd_send_unicast_skb - Send a record via unicast to auditd
719	* @skb: audit record
720	*
721	* Description:
722	* Send a skb to the audit daemon, returns positive/zero values on success and
723	* negative values on failure; in all cases the skb will be consumed by this
724	* function. If the send results in -ECONNREFUSED the connection with auditd
725	* will be reset. This function may sleep so callers should not hold any locks
726	* where this would cause a problem.
727	*/
728	static int auditd_send_unicast_skb(struct sk_buff *skb)
729	{
730	int rc;
731	u32 portid;
732	struct net *net;
733	struct sock *sk;
734	struct auditd_connection *ac;
735
736	/* NOTE: we can't call netlink_unicast while in the RCU section so
737	* take a reference to the network namespace and grab local
738	* copies of the namespace, the sock, and the portid; the
739	* namespace and sock aren't going to go away while we hold a
740	* reference and if the portid does become invalid after the RCU
741	* section netlink_unicast() should safely return an error */
742
743	rcu_read_lock();
744	ac = rcu_dereference(auditd_conn);
745	if (!ac) {
746	rcu_read_unlock();
747	kfree_skb(skb);
748	rc = -ECONNREFUSED;
749	goto err;
750	}
751	net = get_net(ac->net);
752	sk = audit_get_sk(net);
753	portid = ac->portid;
754	rcu_read_unlock();
755
756	rc = netlink_unicast(sk, skb, portid, 0);
757	put_net(net);
758	if (rc < 0)
759	goto err;
760
761	return rc;
762
763	err:
764	if (ac && rc == -ECONNREFUSED)
765	auditd_reset(ac);
766	return rc;
767	}
768
769	/**
770	* kauditd_send_queue - Helper for kauditd_thread to flush skb queues
771	* @sk: the sending sock
772	* @portid: the netlink destination
773	* @queue: the skb queue to process
774	* @retry_limit: limit on number of netlink unicast failures
775	* @skb_hook: per-skb hook for additional processing
776	* @err_hook: hook called if the skb fails the netlink unicast send
777	*
778	* Description:
779	* Run through the given queue and attempt to send the audit records to auditd,
780	* returns zero on success, negative values on failure. It is up to the caller
781	* to ensure that the @sk is valid for the duration of this function.
782	*
783	*/
784	static int kauditd_send_queue(struct sock *sk, u32 portid,
785	struct sk_buff_head *queue,
786	unsigned int retry_limit,
787	void (skb_hook)(struct sk_buff skb),
788	void (err_hook)(struct sk_buff skb, int error))
789	{
790	int rc = 0;
791	struct sk_buff *skb = NULL;
792	struct sk_buff *skb_tail;
793	unsigned int failed = 0;
794
795	/* NOTE: kauditd_thread takes care of all our locking, we just use
796	* the netlink info passed to us (e.g. sk and portid) */
797
798	skb_tail = skb_peek_tail(queue);
799	while ((skb != skb_tail) && (skb = skb_dequeue(queue))) {
800	/* call the skb_hook for each skb we touch */
801	if (skb_hook)
802	(*skb_hook)(skb);
803
804	/* can we send to anyone via unicast? */
805	if (!sk) {
806	if (err_hook)
807	(*err_hook)(skb, -ECONNREFUSED);
808	continue;
809	}
810
811	retry:
812	/* grab an extra skb reference in case of error */
813	skb_get(skb);
814	rc = netlink_unicast(sk, skb, portid, 0);
815	if (rc < 0) {
816	/* send failed - try a few times unless fatal error */
817	if (++failed >= retry_limit \|\|
818	rc == -ECONNREFUSED \|\| rc == -EPERM) {
819	sk = NULL;
820	if (err_hook)
821	(*err_hook)(skb, rc);
822	if (rc == -EAGAIN)
823	rc = 0;
824	/* continue to drain the queue */
825	continue;
826	} else
827	goto retry;
828	} else {
829	/* skb sent - drop the extra reference and continue */
830	consume_skb(skb);
831	failed = 0;
832	}
833	}
834
835	return (rc >= 0 ? 0 : rc);
836	}
837
838	/*
839	* kauditd_send_multicast_skb - Send a record to any multicast listeners
840	* @skb: audit record
841	*
842	* Description:
843	* Write a multicast message to anyone listening in the initial network
844	* namespace. This function doesn't consume an skb as might be expected since
845	* it has to copy it anyways.
846	*/
847	static void kauditd_send_multicast_skb(struct sk_buff *skb)
848	{
849	struct sk_buff *copy;
850	struct sock *sock = audit_get_sk(&init_net);
851	struct nlmsghdr *nlh;
852
853	/* NOTE: we are not taking an additional reference for init_net since
854	* we don't have to worry about it going away */
855
856	if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
857	return;
858
859	/*
860	* The seemingly wasteful skb_copy() rather than bumping the refcount
861	* using skb_get() is necessary because non-standard mods are made to
862	* the skb by the original kaudit unicast socket send routine. The
863	* existing auditd daemon assumes this breakage. Fixing this would
864	* require co-ordinating a change in the established protocol between
865	* the kaudit kernel subsystem and the auditd userspace code. There is
866	* no reason for new multicast clients to continue with this
867	* non-compliance.
868	*/
869	copy = skb_copy(skb, GFP_KERNEL);
870	if (!copy)
871	return;
872	nlh = nlmsg_hdr(copy);
873	nlh->nlmsg_len = skb->len;
874
875	nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL);
876	}
877
878	/**
879	* kauditd_thread - Worker thread to send audit records to userspace
880	* @dummy: unused
881	*/
882	static int kauditd_thread(void *dummy)
883	{
884	int rc;
885	u32 portid = 0;
886	struct net *net = NULL;
887	struct sock *sk = NULL;
888	struct auditd_connection *ac;
889
890	#define UNICAST_RETRIES 5
891
892	set_freezable();
893	while (!kthread_should_stop()) {
894	/* NOTE: see the lock comments in auditd_send_unicast_skb() */
895	rcu_read_lock();
896	ac = rcu_dereference(auditd_conn);
897	if (!ac) {
898	rcu_read_unlock();
899	goto main_queue;
900	}
901	net = get_net(ac->net);
902	sk = audit_get_sk(net);
903	portid = ac->portid;
904	rcu_read_unlock();
905
906	/* attempt to flush the hold queue */
907	rc = kauditd_send_queue(sk, portid,
908	&audit_hold_queue, UNICAST_RETRIES,
909	NULL, kauditd_rehold_skb);
910	if (rc < 0) {
911	sk = NULL;
912	auditd_reset(ac);
913	goto main_queue;
914	}
915
916	/* attempt to flush the retry queue */
917	rc = kauditd_send_queue(sk, portid,
918	&audit_retry_queue, UNICAST_RETRIES,
919	NULL, kauditd_hold_skb);
920	if (rc < 0) {
921	sk = NULL;
922	auditd_reset(ac);
923	goto main_queue;
924	}
925
926	main_queue:
927	/* process the main queue - do the multicast send and attempt
928	* unicast, dump failed record sends to the retry queue; if
929	* sk == NULL due to previous failures we will just do the
930	* multicast send and move the record to the hold queue */
931	rc = kauditd_send_queue(sk, portid, &audit_queue, 1,
932	kauditd_send_multicast_skb,
933	(sk ?
934	kauditd_retry_skb : kauditd_hold_skb));
935	if (ac && rc < 0)
936	auditd_reset(ac);
937	sk = NULL;
938
939	/* drop our netns reference, no auditd sends past this line */
940	if (net) {
941	put_net(net);
942	net = NULL;
943	}
944
945	/* we have processed all the queues so wake everyone */
946	wake_up(&audit_backlog_wait);
947
948	/* NOTE: we want to wake up if there is anything on the queue,
949	* regardless of if an auditd is connected, as we need to
950	* do the multicast send and rotate records from the
951	* main queue to the retry/hold queues */
952	wait_event_freezable(kauditd_wait,
953	(skb_queue_len(&audit_queue) ? 1 : 0));
954	}
955
956	return 0;
957	}
958
959	int audit_send_list_thread(void *_dest)
960	{
961	struct audit_netlink_list *dest = _dest;
962	struct sk_buff *skb;
963	struct sock *sk = audit_get_sk(dest->net);
964
965	/* wait for parent to finish and send an ACK */
966	audit_ctl_lock();
967	audit_ctl_unlock();
968
969	while ((skb = __skb_dequeue(&dest->q)) != NULL)
970	netlink_unicast(sk, skb, dest->portid, 0);
971
972	put_net(dest->net);
973	kfree(dest);
974
975	return 0;
976	}
977
978	struct sk_buff *audit_make_reply(int seq, int type, int done,
979	int multi, const void *payload, int size)
980	{
981	struct sk_buff *skb;
982	struct nlmsghdr *nlh;
983	void *data;
984	int flags = multi ? NLM_F_MULTI : 0;
985	int t = done ? NLMSG_DONE : type;
986
987	skb = nlmsg_new(size, GFP_KERNEL);
988	if (!skb)
989	return NULL;
990
991	nlh = nlmsg_put(skb, 0, seq, t, size, flags);
992	if (!nlh)
993	goto out_kfree_skb;
994	data = nlmsg_data(nlh);
995	memcpy(data, payload, size);
996	return skb;
997
998	out_kfree_skb:
999	kfree_skb(skb);
1000	return NULL;
1001	}
1002
1003	static void audit_free_reply(struct audit_reply *reply)
1004	{
1005	if (!reply)
1006	return;
1007
1008	kfree_skb(reply->skb);
1009	if (reply->net)
1010	put_net(reply->net);
1011	kfree(reply);
1012	}
1013
1014	static int audit_send_reply_thread(void *arg)
1015	{
1016	struct audit_reply reply = (struct audit_reply )arg;
1017
1018	audit_ctl_lock();
1019	audit_ctl_unlock();
1020
1021	/* Ignore failure. It'll only happen if the sender goes away,
1022	because our timeout is set to infinite. */
1023	netlink_unicast(audit_get_sk(reply->net), reply->skb, reply->portid, 0);
1024	reply->skb = NULL;
1025	audit_free_reply(reply);
1026	return 0;
1027	}
1028
1029	/**
1030	* audit_send_reply - send an audit reply message via netlink
1031	* @request_skb: skb of request we are replying to (used to target the reply)
1032	* @seq: sequence number
1033	* @type: audit message type
1034	* @done: done (last) flag
1035	* @multi: multi-part message flag
1036	* @payload: payload data
1037	* @size: payload size
1038	*
1039	* Allocates a skb, builds the netlink message, and sends it to the port id.
1040	*/
1041	static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
1042	int multi, const void *payload, int size)
1043	{
1044	struct task_struct *tsk;
1045	struct audit_reply *reply;
1046
1047	reply = kzalloc_obj(*reply);
1048	if (!reply)
1049	return;
1050
1051	reply->skb = audit_make_reply(seq, type, done, multi, payload, size);
1052	if (!reply->skb)
1053	goto err;
1054	reply->net = get_net(sock_net(NETLINK_CB(request_skb).sk));
1055	reply->portid = NETLINK_CB(request_skb).portid;
1056
1057	tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
1058	if (IS_ERR(tsk))
1059	goto err;
1060
1061	return;
1062
1063	err:
1064	audit_free_reply(reply);
1065	}
1066
1067	/*
1068	* Check for appropriate CAP_AUDIT_ capabilities on incoming audit
1069	* control messages.
1070	*/
1071	static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
1072	{
1073	int err = 0;
1074
1075	/* Only support initial user namespace for now. */
1076	/*
1077	* We return ECONNREFUSED because it tricks userspace into thinking
1078	* that audit was not configured into the kernel. Lots of users
1079	* configure their PAM stack (because that's what the distro does)
1080	* to reject login if unable to send messages to audit. If we return
1081	* ECONNREFUSED the PAM stack thinks the kernel does not have audit
1082	* configured in and will let login proceed. If we return EPERM
1083	* userspace will reject all logins. This should be removed when we
1084	* support non init namespaces!!
1085	*/
1086	if (current_user_ns() != &init_user_ns)
1087	return -ECONNREFUSED;
1088
1089	switch (msg_type) {
1090	case AUDIT_LIST:
1091	case AUDIT_ADD:
1092	case AUDIT_DEL:
1093	return -EOPNOTSUPP;
1094	case AUDIT_GET:
1095	case AUDIT_SET:
1096	case AUDIT_GET_FEATURE:
1097	case AUDIT_SET_FEATURE:
1098	case AUDIT_LIST_RULES:
1099	case AUDIT_ADD_RULE:
1100	case AUDIT_DEL_RULE:
1101	case AUDIT_SIGNAL_INFO:
1102	case AUDIT_TTY_GET:
1103	case AUDIT_TTY_SET:
1104	case AUDIT_TRIM:
1105	case AUDIT_MAKE_EQUIV:
1106	/* Only support auditd and auditctl in initial pid namespace
1107	* for now. */
1108	if (task_active_pid_ns(current) != &init_pid_ns)
1109	return -EPERM;
1110
1111	if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
1112	err = -EPERM;
1113	break;
1114	case AUDIT_USER:
1115	case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1116	case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1117	if (!netlink_capable(skb, CAP_AUDIT_WRITE))
1118	err = -EPERM;
1119	break;
1120	default: /* bad msg */
1121	err = -EINVAL;
1122	}
1123
1124	return err;
1125	}
1126
1127	static void audit_log_common_recv_msg(struct audit_context *context,
1128	struct audit_buffer **ab, u16 msg_type)
1129	{
1130	uid_t uid = from_kuid(&init_user_ns, current_uid());
1131	pid_t pid = task_tgid_nr(current);
1132
1133	if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
1134	*ab = NULL;
1135	return;
1136	}
1137
1138	*ab = audit_log_start(context, GFP_KERNEL, msg_type);
1139	if (unlikely(!*ab))
1140	return;
1141	audit_log_format(*ab, "pid=%d uid=%u ", pid, uid);
1142	audit_log_session_info(*ab);
1143	audit_log_task_context(*ab);
1144	}
1145
1146	static inline void audit_log_user_recv_msg(struct audit_buffer **ab,
1147	u16 msg_type)
1148	{
1149	audit_log_common_recv_msg(NULL, ab, msg_type);
1150	}
1151
1152	static int is_audit_feature_set(int i)
1153	{
1154	return af.features & AUDIT_FEATURE_TO_MASK(i);
1155	}
1156
1157	static int audit_get_feature(struct sk_buff *skb)
1158	{
1159	u32 seq;
1160
1161	seq = nlmsg_hdr(skb)->nlmsg_seq;
1162
1163	audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af));
1164
1165	return 0;
1166	}
1167
1168	static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
1169	u32 old_lock, u32 new_lock, int res)
1170	{
1171	struct audit_buffer *ab;
1172
1173	if (audit_enabled == AUDIT_OFF)
1174	return;
1175
1176	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_FEATURE_CHANGE);
1177	if (!ab)
1178	return;
1179	audit_log_task_info(ab);
1180	audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
1181	audit_feature_names[which], !!old_feature, !!new_feature,
1182	!!old_lock, !!new_lock, res);
1183	audit_log_end(ab);
1184	}
1185
1186	static int audit_set_feature(struct audit_features *uaf)
1187	{
1188	int i;
1189
1190	BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
1191
1192	/* if there is ever a version 2 we should handle that here */
1193
1194	for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1195	u32 feature = AUDIT_FEATURE_TO_MASK(i);
1196	u32 old_feature, new_feature, old_lock, new_lock;
1197
1198	/* if we are not changing this feature, move along */
1199	if (!(feature & uaf->mask))
1200	continue;
1201
1202	old_feature = af.features & feature;
1203	new_feature = uaf->features & feature;
1204	new_lock = (uaf->lock \| af.lock) & feature;
1205	old_lock = af.lock & feature;
1206
1207	/* are we changing a locked feature? */
1208	if (old_lock && (new_feature != old_feature)) {
1209	audit_log_feature_change(i, old_feature, new_feature,
1210	old_lock, new_lock, 0);
1211	return -EPERM;
1212	}
1213	}
1214	/* nothing invalid, do the changes */
1215	for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1216	u32 feature = AUDIT_FEATURE_TO_MASK(i);
1217	u32 old_feature, new_feature, old_lock, new_lock;
1218
1219	/* if we are not changing this feature, move along */
1220	if (!(feature & uaf->mask))
1221	continue;
1222
1223	old_feature = af.features & feature;
1224	new_feature = uaf->features & feature;
1225	old_lock = af.lock & feature;
1226	new_lock = (uaf->lock \| af.lock) & feature;
1227
1228	if (new_feature != old_feature)
1229	audit_log_feature_change(i, old_feature, new_feature,
1230	old_lock, new_lock, 1);
1231
1232	if (new_feature)
1233	af.features \|= feature;
1234	else
1235	af.features &= ~feature;
1236	af.lock \|= new_lock;
1237	}
1238
1239	return 0;
1240	}
1241
1242	static int audit_replace(struct pid *pid)
1243	{
1244	pid_t pvnr;
1245	struct sk_buff *skb;
1246
1247	pvnr = pid_vnr(pid);
1248	skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pvnr, sizeof(pvnr));
1249	if (!skb)
1250	return -ENOMEM;
1251	return auditd_send_unicast_skb(skb);
1252	}
1253
1254	static int audit_receive_msg(struct sk_buff skb, struct nlmsghdr nlh,
1255	bool *ack)
1256	{
1257	u32 seq;
1258	void *data;
1259	int data_len;
1260	int err;
1261	struct audit_buffer *ab;
1262	u16 msg_type = nlh->nlmsg_type;
1263	struct audit_sig_info *sig_data;
1264	struct lsm_context lsmctx = { NULL, 0, 0 };
1265
1266	err = audit_netlink_ok(skb, msg_type);
1267	if (err)
1268	return err;
1269
1270	seq = nlh->nlmsg_seq;
1271	data = nlmsg_data(nlh);
1272	data_len = nlmsg_len(nlh);
1273
1274	switch (msg_type) {
1275	case AUDIT_GET: {
1276	struct audit_status s;
1277	memset(&s, 0, sizeof(s));
1278	s.enabled = audit_enabled;
1279	s.failure = audit_failure;
1280	/* NOTE: use pid_vnr() so the PID is relative to the current
1281	* namespace */
1282	s.pid = auditd_pid_vnr();
1283	s.rate_limit = audit_rate_limit;
1284	s.backlog_limit = audit_backlog_limit;
1285	s.lost = atomic_read(&audit_lost);
1286	s.backlog = skb_queue_len(&audit_queue);
1287	s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL;
1288	s.backlog_wait_time = audit_backlog_wait_time;
1289	s.backlog_wait_time_actual = atomic_read(&audit_backlog_wait_time_actual);
1290	audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
1291	break;
1292	}
1293	case AUDIT_SET: {
1294	struct audit_status s;
1295	memset(&s, 0, sizeof(s));
1296	/* guard against past and future API changes */
1297	memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
1298	if (s.mask & ~AUDIT_STATUS_ALL)
1299	return -EINVAL;
1300	if (s.mask & AUDIT_STATUS_ENABLED) {
1301	err = audit_set_enabled(s.enabled);
1302	if (err < 0)
1303	return err;
1304	}
1305	if (s.mask & AUDIT_STATUS_FAILURE) {
1306	err = audit_set_failure(s.failure);
1307	if (err < 0)
1308	return err;
1309	}
1310	if (s.mask & AUDIT_STATUS_PID) {
1311	/* NOTE: we are using the vnr PID functions below
1312	* because the s.pid value is relative to the
1313	* namespace of the caller; at present this
1314	* doesn't matter much since you can really only
1315	* run auditd from the initial pid namespace, but
1316	* something to keep in mind if this changes */
1317	pid_t new_pid = s.pid;
1318	pid_t auditd_pid;
1319	struct pid *req_pid = task_tgid(current);
1320
1321	/* Sanity check - PID values must match. Setting
1322	* pid to 0 is how auditd ends auditing. */
1323	if (new_pid && (new_pid != pid_vnr(req_pid)))
1324	return -EINVAL;
1325
1326	/* test the auditd connection */
1327	audit_replace(req_pid);
1328
1329	auditd_pid = auditd_pid_vnr();
1330	if (auditd_pid) {
1331	/* replacing a healthy auditd is not allowed */
1332	if (new_pid) {
1333	audit_log_config_change("audit_pid",
1334	new_pid, auditd_pid, 0);
1335	return -EEXIST;
1336	}
1337	/* only current auditd can unregister itself */
1338	if (pid_vnr(req_pid) != auditd_pid) {
1339	audit_log_config_change("audit_pid",
1340	new_pid, auditd_pid, 0);
1341	return -EACCES;
1342	}
1343	}
1344
1345	if (new_pid) {
1346	/* register a new auditd connection */
1347	err = auditd_set(req_pid,
1348	NETLINK_CB(skb).portid,
1349	sock_net(NETLINK_CB(skb).sk),
1350	skb, ack);
1351	if (audit_enabled != AUDIT_OFF)
1352	audit_log_config_change("audit_pid",
1353	new_pid,
1354	auditd_pid,
1355	err ? 0 : 1);
1356	if (err)
1357	return err;
1358
1359	/* try to process any backlog */
1360	wake_up_interruptible(&kauditd_wait);
1361	} else {
1362	if (audit_enabled != AUDIT_OFF)
1363	audit_log_config_change("audit_pid",
1364	new_pid,
1365	auditd_pid, 1);
1366
1367	/* unregister the auditd connection */
1368	auditd_reset(NULL);
1369	}
1370	}
1371	if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
1372	err = audit_set_rate_limit(s.rate_limit);
1373	if (err < 0)
1374	return err;
1375	}
1376	if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
1377	err = audit_set_backlog_limit(s.backlog_limit);
1378	if (err < 0)
1379	return err;
1380	}
1381	if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
1382	if (sizeof(s) > (size_t)nlh->nlmsg_len)
1383	return -EINVAL;
1384	if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
1385	return -EINVAL;
1386	err = audit_set_backlog_wait_time(s.backlog_wait_time);
1387	if (err < 0)
1388	return err;
1389	}
1390	if (s.mask == AUDIT_STATUS_LOST) {
1391	u32 lost = atomic_xchg(&audit_lost, 0);
1392
1393	audit_log_config_change("lost", 0, lost, 1);
1394	return lost;
1395	}
1396	if (s.mask == AUDIT_STATUS_BACKLOG_WAIT_TIME_ACTUAL) {
1397	u32 actual = atomic_xchg(&audit_backlog_wait_time_actual, 0);
1398
1399	audit_log_config_change("backlog_wait_time_actual", 0, actual, 1);
1400	return actual;
1401	}
1402	break;
1403	}
1404	case AUDIT_GET_FEATURE:
1405	err = audit_get_feature(skb);
1406	if (err)
1407	return err;
1408	break;
1409	case AUDIT_SET_FEATURE:
1410	if (data_len < sizeof(struct audit_features))
1411	return -EINVAL;
1412	err = audit_set_feature(data);
1413	if (err)
1414	return err;
1415	break;
1416	case AUDIT_USER:
1417	case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1418	case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1419	if (!audit_enabled && msg_type != AUDIT_USER_AVC)
1420	return 0;
1421	/* exit early if there isn't at least one character to print */
1422	if (data_len < 2)
1423	return -EINVAL;
1424
1425	err = audit_filter(msg_type, AUDIT_FILTER_USER);
1426	if (err == 1) { /* match or error */
1427	char *str = data;
1428
1429	err = 0;
1430	if (msg_type == AUDIT_USER_TTY) {
1431	err = tty_audit_push();
1432	if (err)
1433	break;
1434	}
1435	audit_log_user_recv_msg(&ab, msg_type);
1436	if (msg_type != AUDIT_USER_TTY) {
1437	/* ensure NULL termination */
1438	str[data_len - 1] = '\0';
1439	audit_log_format(ab, " msg='%.*s'",
1440	AUDIT_MESSAGE_TEXT_MAX,
1441	str);
1442	} else {
1443	audit_log_format(ab, " data=");
1444	if (str[data_len - 1] == '\0')
1445	data_len--;
1446	audit_log_n_untrustedstring(ab, str, data_len);
1447	}
1448	audit_log_end(ab);
1449	}
1450	break;
1451	case AUDIT_ADD_RULE:
1452	case AUDIT_DEL_RULE:
1453	if (data_len < sizeof(struct audit_rule_data))
1454	return -EINVAL;
1455	if (audit_enabled == AUDIT_LOCKED) {
1456	audit_log_common_recv_msg(audit_context(), &ab,
1457	AUDIT_CONFIG_CHANGE);
1458	audit_log_format(ab, " op=%s audit_enabled=%d res=0",
1459	msg_type == AUDIT_ADD_RULE ?
1460	"add_rule" : "remove_rule",
1461	audit_enabled);
1462	audit_log_end(ab);
1463	return -EPERM;
1464	}
1465	err = audit_rule_change(msg_type, seq, data, data_len);
1466	break;
1467	case AUDIT_LIST_RULES:
1468	err = audit_list_rules_send(skb, seq);
1469	break;
1470	case AUDIT_TRIM:
1471	if (audit_enabled == AUDIT_LOCKED)
1472	return -EPERM;
1473	audit_trim_trees();
1474	audit_log_common_recv_msg(audit_context(), &ab,
1475	AUDIT_CONFIG_CHANGE);
1476	audit_log_format(ab, " op=trim res=1");
1477	audit_log_end(ab);
1478	break;
1479	case AUDIT_MAKE_EQUIV: {
1480	void *bufp = data;
1481	u32 sizes[2];
1482	size_t msglen = data_len;
1483	char old, new;
1484
1485	if (audit_enabled == AUDIT_LOCKED)
1486	return -EPERM;
1487	err = -EINVAL;
1488	if (msglen < 2 * sizeof(u32))
1489	break;
1490	memcpy(sizes, bufp, 2 * sizeof(u32));
1491	bufp += 2 * sizeof(u32);
1492	msglen -= 2 * sizeof(u32);
1493	old = audit_unpack_string(&bufp, &msglen, sizes[0]);
1494	if (IS_ERR(old)) {
1495	err = PTR_ERR(old);
1496	break;
1497	}
1498	new = audit_unpack_string(&bufp, &msglen, sizes[1]);
1499	if (IS_ERR(new)) {
1500	err = PTR_ERR(new);
1501	kfree(old);
1502	break;
1503	}
1504	/* OK, here comes... */
1505	err = audit_tag_tree(old, new);
1506
1507	audit_log_common_recv_msg(audit_context(), &ab,
1508	AUDIT_CONFIG_CHANGE);
1509	audit_log_format(ab, " op=make_equiv old=");
1510	audit_log_untrustedstring(ab, old);
1511	audit_log_format(ab, " new=");
1512	audit_log_untrustedstring(ab, new);
1513	audit_log_format(ab, " res=%d", !err);
1514	audit_log_end(ab);
1515	kfree(old);
1516	kfree(new);
1517	break;
1518	}
1519	case AUDIT_SIGNAL_INFO:
1520	if (lsmprop_is_set(&audit_sig_lsm)) {
1521	err = security_lsmprop_to_secctx(&audit_sig_lsm,
1522	&lsmctx, LSM_ID_UNDEF);
1523	if (err < 0)
1524	return err;
1525	}
1526	sig_data = kmalloc_flex(*sig_data, ctx, lsmctx.len);
1527	if (!sig_data) {
1528	if (lsmprop_is_set(&audit_sig_lsm))
1529	security_release_secctx(&lsmctx);
1530	return -ENOMEM;
1531	}
1532	sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
1533	sig_data->pid = audit_sig_pid;
1534	if (lsmprop_is_set(&audit_sig_lsm)) {
1535	memcpy(sig_data->ctx, lsmctx.context, lsmctx.len);
1536	security_release_secctx(&lsmctx);
1537	}
1538	audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
1539	sig_data, struct_size(sig_data, ctx,
1540	lsmctx.len));
1541	kfree(sig_data);
1542	break;
1543	case AUDIT_TTY_GET: {
1544	struct audit_tty_status s;
1545	unsigned int t;
1546
1547	t = READ_ONCE(current->signal->audit_tty);
1548	s.enabled = t & AUDIT_TTY_ENABLE;
1549	s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1550
1551	audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
1552	break;
1553	}
1554	case AUDIT_TTY_SET: {
1555	struct audit_tty_status s, old;
1556	struct audit_buffer *ab;
1557	unsigned int t;
1558
1559	memset(&s, 0, sizeof(s));
1560	/* guard against past and future API changes */
1561	memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
1562	/* check if new data is valid */
1563	if ((s.enabled != 0 && s.enabled != 1) \|\|
1564	(s.log_passwd != 0 && s.log_passwd != 1))
1565	err = -EINVAL;
1566
1567	if (err)
1568	t = READ_ONCE(current->signal->audit_tty);
1569	else {
1570	t = s.enabled \| (-s.log_passwd & AUDIT_TTY_LOG_PASSWD);
1571	t = xchg(&current->signal->audit_tty, t);
1572	}
1573	old.enabled = t & AUDIT_TTY_ENABLE;
1574	old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1575
1576	audit_log_common_recv_msg(audit_context(), &ab,
1577	AUDIT_CONFIG_CHANGE);
1578	audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
1579	" old-log_passwd=%d new-log_passwd=%d res=%d",
1580	old.enabled, s.enabled, old.log_passwd,
1581	s.log_passwd, !err);
1582	audit_log_end(ab);
1583	break;
1584	}
1585	default:
1586	err = -EINVAL;
1587	break;
1588	}
1589
1590	return err < 0 ? err : 0;
1591	}
1592
1593	/**
1594	* audit_receive - receive messages from a netlink control socket
1595	* @skb: the message buffer
1596	*
1597	* Parse the provided skb and deal with any messages that may be present,
1598	* malformed skbs are discarded.
1599	*/
1600	static void audit_receive(struct sk_buff *skb)
1601	{
1602	struct nlmsghdr *nlh;
1603	bool ack;
1604	/*
1605	* len MUST be signed for nlmsg_next to be able to dec it below 0
1606	* if the nlmsg_len was not aligned
1607	*/
1608	int len;
1609	int err;
1610
1611	nlh = nlmsg_hdr(skb);
1612	len = skb->len;
1613
1614	audit_ctl_lock();
1615	while (nlmsg_ok(nlh, len)) {
1616	ack = nlh->nlmsg_flags & NLM_F_ACK;
1617	err = audit_receive_msg(skb, nlh, &ack);
1618
1619	/* send an ack if the user asked for one and audit_receive_msg
1620	* didn't already do it, or if there was an error. */
1621	if (ack \|\| err)
1622	netlink_ack(skb, nlh, err, NULL);
1623
1624	nlh = nlmsg_next(nlh, &len);
1625	}
1626	audit_ctl_unlock();
1627
1628	/* can't block with the ctrl lock, so penalize the sender now */
1629	if (audit_backlog_limit &&
1630	(skb_queue_len(&audit_queue) > audit_backlog_limit)) {
1631	DECLARE_WAITQUEUE(wait, current);
1632
1633	/* wake kauditd to try and flush the queue */
1634	wake_up_interruptible(&kauditd_wait);
1635
1636	add_wait_queue_exclusive(&audit_backlog_wait, &wait);
1637	set_current_state(TASK_UNINTERRUPTIBLE);
1638	schedule_timeout(audit_backlog_wait_time);
1639	remove_wait_queue(&audit_backlog_wait, &wait);
1640	}
1641	}
1642
1643	/* Log information about who is connecting to the audit multicast socket */
1644	static void audit_log_multicast(int group, const char *op, int err)
1645	{
1646	const struct cred *cred;
1647	struct tty_struct *tty;
1648	char comm[sizeof(current->comm)];
1649	struct audit_buffer *ab;
1650
1651	if (!audit_enabled)
1652	return;
1653
1654	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_EVENT_LISTENER);
1655	if (!ab)
1656	return;
1657
1658	cred = current_cred();
1659	tty = audit_get_tty();
1660	audit_log_format(ab, "pid=%u uid=%u auid=%u tty=%s ses=%u",
1661	task_tgid_nr(current),
1662	from_kuid(&init_user_ns, cred->uid),
1663	from_kuid(&init_user_ns, audit_get_loginuid(current)),
1664	tty ? tty_name(tty) : "(none)",
1665	audit_get_sessionid(current));
1666	audit_put_tty(tty);
1667	audit_log_task_context(ab); /* subj= */
1668	audit_log_format(ab, " comm=");
1669	audit_log_untrustedstring(ab, get_task_comm(comm, current));
1670	audit_log_d_path_exe(ab, current->mm); /* exe= */
1671	audit_log_format(ab, " nl-mcgrp=%d op=%s res=%d", group, op, !err);
1672	audit_log_end(ab);
1673	}
1674
1675	/* Run custom bind function on netlink socket group connect or bind requests. */
1676	static int audit_multicast_bind(struct net *net, int group)
1677	{
1678	int err = 0;
1679
1680	if (!capable(CAP_AUDIT_READ))
1681	err = -EPERM;
1682	audit_log_multicast(group, "connect", err);
1683	return err;
1684	}
1685
1686	static void audit_multicast_unbind(struct net *net, int group)
1687	{
1688	audit_log_multicast(group, "disconnect", 0);
1689	}
1690
1691	static int __net_init audit_net_init(struct net *net)
1692	{
1693	struct netlink_kernel_cfg cfg = {
1694	.input = audit_receive,
1695	.bind = audit_multicast_bind,
1696	.unbind = audit_multicast_unbind,
1697	.flags = NL_CFG_F_NONROOT_RECV,
1698	.groups = AUDIT_NLGRP_MAX,
1699	};
1700
1701	struct audit_net *aunet = net_generic(net, audit_net_id);
1702
1703	aunet->sk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
1704	if (aunet->sk == NULL) {
1705	audit_panic("cannot initialize netlink socket in namespace");
1706	return -ENOMEM;
1707	}
1708	/* limit the timeout in case auditd is blocked/stopped */
1709	aunet->sk->sk_sndtimeo = HZ / 10;
1710
1711	return 0;
1712	}
1713
1714	static void __net_exit audit_net_exit(struct net *net)
1715	{
1716	struct audit_net *aunet = net_generic(net, audit_net_id);
1717
1718	/* NOTE: you would think that we would want to check the auditd
1719	* connection and potentially reset it here if it lives in this
1720	* namespace, but since the auditd connection tracking struct holds a
1721	* reference to this namespace (see auditd_set()) we are only ever
1722	* going to get here after that connection has been released */
1723
1724	netlink_kernel_release(aunet->sk);
1725	}
1726
1727	static struct pernet_operations audit_net_ops __net_initdata = {
1728	.init = audit_net_init,
1729	.exit = audit_net_exit,
1730	.id = &audit_net_id,
1731	.size = sizeof(struct audit_net),
1732	};
1733
1734	/* Initialize audit support at boot time. */
1735	static int __init audit_init(void)
1736	{
1737	int i;
1738
1739	if (audit_initialized == AUDIT_DISABLED)
1740	return 0;
1741
1742	audit_buffer_cache = KMEM_CACHE(audit_buffer, SLAB_PANIC);
1743
1744	skb_queue_head_init(&audit_queue);
1745	skb_queue_head_init(&audit_retry_queue);
1746	skb_queue_head_init(&audit_hold_queue);
1747
1748	for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
1749	INIT_LIST_HEAD(&audit_inode_hash[i]);
1750
1751	mutex_init(&audit_cmd_mutex.lock);
1752	audit_cmd_mutex.owner = NULL;
1753
1754	pr_info("initializing netlink subsys (%s)\n",
1755	str_enabled_disabled(audit_default));
1756	register_pernet_subsys(&audit_net_ops);
1757
1758	audit_initialized = AUDIT_INITIALIZED;
1759
1760	kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
1761	if (IS_ERR(kauditd_task)) {
1762	int err = PTR_ERR(kauditd_task);
1763	panic("audit: failed to start the kauditd thread (%d)\n", err);
1764	}
1765
1766	audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL,
1767	"state=initialized audit_enabled=%u res=1",
1768	audit_enabled);
1769
1770	return 0;
1771	}
1772	postcore_initcall(audit_init);
1773
1774	/*
1775	* Process kernel command-line parameter at boot time.
1776	* audit={0\|off} or audit={1\|on}.
1777	*/
1778	static int __init audit_enable(char *str)
1779	{
1780	if (!strcasecmp(str, "off") \|\| !strcmp(str, "0"))
1781	audit_default = AUDIT_OFF;
1782	else if (!strcasecmp(str, "on") \|\| !strcmp(str, "1"))
1783	audit_default = AUDIT_ON;
1784	else {
1785	pr_err("audit: invalid 'audit' parameter value (%s)\n", str);
1786	audit_default = AUDIT_ON;
1787	}
1788
1789	if (audit_default == AUDIT_OFF)
1790	audit_initialized = AUDIT_DISABLED;
1791	if (audit_set_enabled(audit_default))
1792	pr_err("audit: error setting audit state (%d)\n",
1793	audit_default);
1794
1795	pr_info("%s\n", audit_default ?
1796	"enabled (after initialization)" : "disabled (until reboot)");
1797
1798	return 1;
1799	}
1800	__setup("audit=", audit_enable);
1801
1802	/* Process kernel command-line parameter at boot time.
1803	* audit_backlog_limit=<n> */
1804	static int __init audit_backlog_limit_set(char *str)
1805	{
1806	u32 audit_backlog_limit_arg;
1807
1808	pr_info("audit_backlog_limit: ");
1809	if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
1810	pr_cont("using default of %u, unable to parse %s\n",
1811	audit_backlog_limit, str);
1812	return 1;
1813	}
1814
1815	audit_backlog_limit = audit_backlog_limit_arg;
1816	pr_cont("%d\n", audit_backlog_limit);
1817
1818	return 1;
1819	}
1820	__setup("audit_backlog_limit=", audit_backlog_limit_set);
1821
1822	static void audit_buffer_free(struct audit_buffer *ab)
1823	{
1824	struct sk_buff *skb;
1825
1826	if (!ab)
1827	return;
1828
1829	while ((skb = skb_dequeue(&ab->skb_list)))
1830	kfree_skb(skb);
1831	kmem_cache_free(audit_buffer_cache, ab);
1832	}
1833
1834	static struct audit_buffer audit_buffer_alloc(struct audit_context ctx,
1835	gfp_t gfp_mask, int type)
1836	{
1837	struct audit_buffer *ab;
1838
1839	ab = kmem_cache_alloc(audit_buffer_cache, gfp_mask);
1840	if (!ab)
1841	return NULL;
1842
1843	skb_queue_head_init(&ab->skb_list);
1844
1845	ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
1846	if (!ab->skb)
1847	goto err;
1848
1849	skb_queue_tail(&ab->skb_list, ab->skb);
1850
1851	if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0))
1852	goto err;
1853
1854	ab->ctx = ctx;
1855	ab->gfp_mask = gfp_mask;
1856
1857	return ab;
1858
1859	err:
1860	audit_buffer_free(ab);
1861	return NULL;
1862	}
1863
1864	/**
1865	* audit_serial - compute a serial number for the audit record
1866	*
1867	* Compute a serial number for the audit record. Audit records are
1868	* written to user-space as soon as they are generated, so a complete
1869	* audit record may be written in several pieces. The timestamp of the
1870	* record and this serial number are used by the user-space tools to
1871	* determine which pieces belong to the same audit record. The
1872	* (timestamp,serial) tuple is unique for each syscall and is live from
1873	* syscall entry to syscall exit.
1874	*
1875	* NOTE: Another possibility is to store the formatted records off the
1876	* audit context (for those records that have a context), and emit them
1877	* all at syscall exit. However, this could delay the reporting of
1878	* significant errors until syscall exit (or never, if the system
1879	* halts).
1880	*/
1881	unsigned int audit_serial(void)
1882	{
1883	static atomic_t serial = ATOMIC_INIT(0);
1884
1885	return atomic_inc_return(&serial);
1886	}
1887
1888	static inline void audit_get_stamp(struct audit_context *ctx,
1889	struct audit_stamp *stamp)
1890	{
1891	if (!ctx \|\| !auditsc_get_stamp(ctx, stamp)) {
1892	ktime_get_coarse_real_ts64(&stamp->ctime);
1893	stamp->serial = audit_serial();
1894	}
1895	}
1896
1897	/**
1898	* audit_log_start - obtain an audit buffer
1899	* @ctx: audit_context (may be NULL)
1900	* @gfp_mask: type of allocation
1901	* @type: audit message type
1902	*
1903	* Returns audit_buffer pointer on success or NULL on error.
1904	*
1905	* Obtain an audit buffer. This routine does locking to obtain the
1906	* audit buffer, but then no locking is required for calls to
1907	* audit_log_*format. If the task (ctx) is a task that is currently in a
1908	* syscall, then the syscall is marked as auditable and an audit record
1909	* will be written at syscall exit. If there is no associated task, then
1910	* task context (ctx) should be NULL.
1911	*/
1912	struct audit_buffer audit_log_start(struct audit_context ctx, gfp_t gfp_mask,
1913	int type)
1914	{
1915	struct audit_buffer *ab;
1916
1917	if (audit_initialized != AUDIT_INITIALIZED)
1918	return NULL;
1919
1920	if (unlikely(!audit_filter(type, AUDIT_FILTER_EXCLUDE)))
1921	return NULL;
1922
1923	/* NOTE: don't ever fail/sleep on these two conditions:
1924	* 1. auditd generated record - since we need auditd to drain the
1925	* queue; also, when we are checking for auditd, compare PIDs using
1926	* task_tgid_vnr() since auditd_pid is set in audit_receive_msg()
1927	* using a PID anchored in the caller's namespace
1928	* 2. generator holding the audit_cmd_mutex - we don't want to block
1929	* while holding the mutex, although we do penalize the sender
1930	* later in audit_receive() when it is safe to block
1931	*/
1932	if (!(auditd_test_task(current) \|\| audit_ctl_owner_current())) {
1933	long stime = audit_backlog_wait_time;
1934
1935	while (audit_backlog_limit &&
1936	(skb_queue_len(&audit_queue) > audit_backlog_limit)) {
1937	/* wake kauditd to try and flush the queue */
1938	wake_up_interruptible(&kauditd_wait);
1939
1940	/* sleep if we are allowed and we haven't exhausted our
1941	* backlog wait limit */
1942	if (gfpflags_allow_blocking(gfp_mask) && (stime > 0)) {
1943	long rtime = stime;
1944
1945	DECLARE_WAITQUEUE(wait, current);
1946
1947	add_wait_queue_exclusive(&audit_backlog_wait,
1948	&wait);
1949	set_current_state(TASK_UNINTERRUPTIBLE);
1950	stime = schedule_timeout(rtime);
1951	atomic_add(rtime - stime, &audit_backlog_wait_time_actual);
1952	remove_wait_queue(&audit_backlog_wait, &wait);
1953	} else {
1954	if (audit_rate_check() && printk_ratelimit())
1955	pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
1956	skb_queue_len(&audit_queue),
1957	audit_backlog_limit);
1958	audit_log_lost("backlog limit exceeded");
1959	return NULL;
1960	}
1961	}
1962	}
1963
1964	ab = audit_buffer_alloc(ctx, gfp_mask, type);
1965	if (!ab) {
1966	audit_log_lost("out of memory in audit_log_start");
1967	return NULL;
1968	}
1969
1970	audit_get_stamp(ab->ctx, &ab->stamp);
1971	/* cancel dummy context to enable supporting records */
1972	if (ctx)
1973	ctx->dummy = 0;
1974	audit_log_format(ab, "audit(%llu.%03lu:%u): ",
1975	(unsigned long long)ab->stamp.ctime.tv_sec,
1976	ab->stamp.ctime.tv_nsec/1000000,
1977	ab->stamp.serial);
1978
1979	return ab;
1980	}
1981
1982	/**
1983	* audit_expand - expand skb in the audit buffer
1984	* @ab: audit_buffer
1985	* @extra: space to add at tail of the skb
1986	*
1987	* Returns 0 (no space) on failed expansion, or available space if
1988	* successful.
1989	*/
1990	static inline int audit_expand(struct audit_buffer *ab, int extra)
1991	{
1992	struct sk_buff *skb = ab->skb;
1993	int oldtail = skb_tailroom(skb);
1994	int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1995	int newtail = skb_tailroom(skb);
1996
1997	if (ret < 0) {
1998	audit_log_lost("out of memory in audit_expand");
1999	return 0;
2000	}
2001
2002	skb->truesize += newtail - oldtail;
2003	return newtail;
2004	}
2005
2006	/*
2007	* Format an audit message into the audit buffer. If there isn't enough
2008	* room in the audit buffer, more room will be allocated and vsnprint
2009	* will be called a second time. Currently, we assume that a printk
2010	* can't format message larger than 1024 bytes, so we don't either.
2011	*/
2012	static __printf(2, 0)
2013	void audit_log_vformat(struct audit_buffer ab, const char fmt, va_list args)
2014	{
2015	int len, avail;
2016	struct sk_buff *skb;
2017	va_list args2;
2018
2019	if (!ab)
2020	return;
2021
2022	BUG_ON(!ab->skb);
2023	skb = ab->skb;
2024	avail = skb_tailroom(skb);
2025	if (avail == 0) {
2026	avail = audit_expand(ab, AUDIT_BUFSIZ);
2027	if (!avail)
2028	goto out;
2029	}
2030	va_copy(args2, args);
2031	len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
2032	if (len >= avail) {
2033	/* The printk buffer is 1024 bytes long, so if we get
2034	* here and AUDIT_BUFSIZ is at least 1024, then we can
2035	* log everything that printk could have logged. */
2036	avail = audit_expand(ab,
2037	max_t(unsigned int, AUDIT_BUFSIZ, 1+len-avail));
2038	if (!avail)
2039	goto out_va_end;
2040	len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
2041	}
2042	if (len > 0)
2043	skb_put(skb, len);
2044	out_va_end:
2045	va_end(args2);
2046	out:
2047	return;
2048	}
2049
2050	/**
2051	* audit_log_format - format a message into the audit buffer.
2052	* @ab: audit_buffer
2053	* @fmt: format string
2054	* @...: optional parameters matching @fmt string
2055	*
2056	* All the work is done in audit_log_vformat.
2057	*/
2058	void audit_log_format(struct audit_buffer ab, const char fmt, ...)
2059	{
2060	va_list args;
2061
2062	if (!ab)
2063	return;
2064	va_start(args, fmt);
2065	audit_log_vformat(ab, fmt, args);
2066	va_end(args);
2067	}
2068
2069	/**
2070	* audit_log_n_hex - convert a buffer to hex and append it to the audit skb
2071	* @ab: the audit_buffer
2072	* @buf: buffer to convert to hex
2073	* @len: length of @buf to be converted
2074	*
2075	* No return value; failure to expand is silently ignored.
2076	*
2077	* This function will take the passed buf and convert it into a string of
2078	* ascii hex digits. The new string is placed onto the skb.
2079	*/
2080	void audit_log_n_hex(struct audit_buffer ab, const unsigned char buf,
2081	size_t len)
2082	{
2083	int i, avail, new_len;
2084	unsigned char *ptr;
2085	struct sk_buff *skb;
2086
2087	if (!ab)
2088	return;
2089
2090	BUG_ON(!ab->skb);
2091	skb = ab->skb;
2092	avail = skb_tailroom(skb);
2093	new_len = len<<1;
2094	if (new_len >= avail) {
2095	/* Round the buffer request up to the next multiple */
2096	new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
2097	avail = audit_expand(ab, new_len);
2098	if (!avail)
2099	return;
2100	}
2101
2102	ptr = skb_tail_pointer(skb);
2103	for (i = 0; i < len; i++)
2104	ptr = hex_byte_pack_upper(ptr, buf[i]);
2105	*ptr = 0;
2106	skb_put(skb, len << 1); /* new string is twice the old string */
2107	}
2108
2109	/*
2110	* Format a string of no more than slen characters into the audit buffer,
2111	* enclosed in quote marks.
2112	*/
2113	void audit_log_n_string(struct audit_buffer ab, const char string,
2114	size_t slen)
2115	{
2116	int avail, new_len;
2117	unsigned char *ptr;
2118	struct sk_buff *skb;
2119
2120	if (!ab)
2121	return;
2122
2123	BUG_ON(!ab->skb);
2124	skb = ab->skb;
2125	avail = skb_tailroom(skb);
2126	new_len = slen + 3; /* enclosing quotes + null terminator */
2127	if (new_len > avail) {
2128	avail = audit_expand(ab, new_len);
2129	if (!avail)
2130	return;
2131	}
2132	ptr = skb_tail_pointer(skb);
2133	*ptr++ = '"';
2134	memcpy(ptr, string, slen);
2135	ptr += slen;
2136	*ptr++ = '"';
2137	*ptr = 0;
2138	skb_put(skb, slen + 2); /* don't include null terminator */
2139	}
2140
2141	/**
2142	* audit_string_contains_control - does a string need to be logged in hex
2143	* @string: string to be checked
2144	* @len: max length of the string to check
2145	*/
2146	bool audit_string_contains_control(const char *string, size_t len)
2147	{
2148	const unsigned char *p;
2149	for (p = string; p < (const unsigned char *)string + len; p++) {
2150	if (p == '"' \|\| p < 0x21 \|\| *p > 0x7e)
2151	return true;
2152	}
2153	return false;
2154	}
2155
2156	/**
2157	* audit_log_n_untrustedstring - log a string that may contain random characters
2158	* @ab: audit_buffer
2159	* @string: string to be logged
2160	* @len: length of string (not including trailing null)
2161	*
2162	* This code will escape a string that is passed to it if the string
2163	* contains a control character, unprintable character, double quote mark,
2164	* or a space. Unescaped strings will start and end with a double quote mark.
2165	* Strings that are escaped are printed in hex (2 digits per char).
2166	*
2167	* The caller specifies the number of characters in the string to log, which may
2168	* or may not be the entire string.
2169	*/
2170	void audit_log_n_untrustedstring(struct audit_buffer ab, const char string,
2171	size_t len)
2172	{
2173	if (audit_string_contains_control(string, len))
2174	audit_log_n_hex(ab, string, len);
2175	else
2176	audit_log_n_string(ab, string, len);
2177	}
2178
2179	/**
2180	* audit_log_untrustedstring - log a string that may contain random characters
2181	* @ab: audit_buffer
2182	* @string: string to be logged
2183	*
2184	* Same as audit_log_n_untrustedstring(), except that strlen is used to
2185	* determine string length.
2186	*/
2187	void audit_log_untrustedstring(struct audit_buffer ab, const char string)
2188	{
2189	audit_log_n_untrustedstring(ab, string, strlen(string));
2190	}
2191
2192	/* This is a helper-function to print the escaped d_path */
2193	void audit_log_d_path(struct audit_buffer ab, const char prefix,
2194	const struct path *path)
2195	{
2196	char p, pathname;
2197
2198	if (prefix)
2199	audit_log_format(ab, "%s", prefix);
2200
2201	/* We will allow 11 spaces for ' (deleted)' to be appended */
2202	pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
2203	if (!pathname) {
2204	audit_log_format(ab, "\"<no_memory>\"");
2205	return;
2206	}
2207	p = d_path(path, pathname, PATH_MAX+11);
2208	if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
2209	/* FIXME: can we save some information here? */
2210	audit_log_format(ab, "\"<too_long>\"");
2211	} else
2212	audit_log_untrustedstring(ab, p);
2213	kfree(pathname);
2214	}
2215
2216	void audit_log_session_info(struct audit_buffer *ab)
2217	{
2218	unsigned int sessionid = audit_get_sessionid(current);
2219	uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
2220
2221	audit_log_format(ab, "auid=%u ses=%u", auid, sessionid);
2222	}
2223
2224	void audit_log_key(struct audit_buffer ab, char key)
2225	{
2226	audit_log_format(ab, " key=");
2227	if (key)
2228	audit_log_untrustedstring(ab, key);
2229	else
2230	audit_log_format(ab, "(null)");
2231	}
2232
2233	/**
2234	* audit_buffer_aux_new - Add an aux record buffer to the skb list
2235	* @ab: audit_buffer
2236	* @type: message type
2237	*
2238	* Aux records are allocated and added to the skb list of
2239	* the "main" record. The ab->skb is reset to point to the
2240	* aux record on its creation. When the aux record in complete
2241	* ab->skb has to be reset to point to the "main" record.
2242	* This allows the audit_log_ functions to be ignorant of
2243	* which kind of record it is logging to. It also avoids adding
2244	* special data for aux records.
2245	*
2246	* On success ab->skb will point to the new aux record.
2247	* Returns 0 on success, -ENOMEM should allocation fail.
2248	*/
2249	static int audit_buffer_aux_new(struct audit_buffer *ab, int type)
2250	{
2251	WARN_ON(ab->skb != skb_peek(&ab->skb_list));
2252
2253	ab->skb = nlmsg_new(AUDIT_BUFSIZ, ab->gfp_mask);
2254	if (!ab->skb)
2255	goto err;
2256	if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0))
2257	goto err;
2258	skb_queue_tail(&ab->skb_list, ab->skb);
2259
2260	audit_log_format(ab, "audit(%llu.%03lu:%u): ",
2261	(unsigned long long)ab->stamp.ctime.tv_sec,
2262	ab->stamp.ctime.tv_nsec/1000000,
2263	ab->stamp.serial);
2264
2265	return 0;
2266
2267	err:
2268	kfree_skb(ab->skb);
2269	ab->skb = skb_peek(&ab->skb_list);
2270	return -ENOMEM;
2271	}
2272
2273	/**
2274	* audit_buffer_aux_end - Switch back to the "main" record from an aux record
2275	* @ab: audit_buffer
2276	*
2277	* Restores the "main" audit record to ab->skb.
2278	*/
2279	static void audit_buffer_aux_end(struct audit_buffer *ab)
2280	{
2281	ab->skb = skb_peek(&ab->skb_list);
2282	}
2283
2284	/**
2285	* audit_log_subj_ctx - Add LSM subject information
2286	* @ab: audit_buffer
2287	* @prop: LSM subject properties.
2288	*
2289	* Add a subj= field and, if necessary, a AUDIT_MAC_TASK_CONTEXTS record.
2290	*/
2291	int audit_log_subj_ctx(struct audit_buffer ab, struct lsm_prop prop)
2292	{
2293	struct lsm_context ctx;
2294	char *space = "";
2295	int error;
2296	int i;
2297
2298	security_current_getlsmprop_subj(prop);
2299	if (!lsmprop_is_set(prop))
2300	return 0;
2301
2302	if (audit_subj_secctx_cnt < 2) {
2303	error = security_lsmprop_to_secctx(prop, &ctx, LSM_ID_UNDEF);
2304	if (error < 0) {
2305	if (error != -EINVAL)
2306	goto error_path;
2307	return 0;
2308	}
2309	audit_log_format(ab, " subj=%s", ctx.context);
2310	security_release_secctx(&ctx);
2311	return 0;
2312	}
2313	/* Multiple LSMs provide contexts. Include an aux record. */
2314	audit_log_format(ab, " subj=?");
2315	error = audit_buffer_aux_new(ab, AUDIT_MAC_TASK_CONTEXTS);
2316	if (error)
2317	goto error_path;
2318
2319	for (i = 0; i < audit_subj_secctx_cnt; i++) {
2320	error = security_lsmprop_to_secctx(prop, &ctx,
2321	audit_subj_lsms[i]->id);
2322	if (error < 0) {
2323	/*
2324	* Don't print anything. An LSM like BPF could
2325	* claim to support contexts, but only do so under
2326	* certain conditions.
2327	*/
2328	if (error == -EOPNOTSUPP)
2329	continue;
2330	if (error != -EINVAL)
2331	audit_panic("error in audit_log_subj_ctx");
2332	} else {
2333	audit_log_format(ab, "%ssubj_%s=%s", space,
2334	audit_subj_lsms[i]->name, ctx.context);
2335	space = " ";
2336	security_release_secctx(&ctx);
2337	}
2338	}
2339	audit_buffer_aux_end(ab);
2340	return 0;
2341
2342	error_path:
2343	audit_panic("error in audit_log_subj_ctx");
2344	return error;
2345	}
2346	EXPORT_SYMBOL(audit_log_subj_ctx);
2347
2348	int audit_log_task_context(struct audit_buffer *ab)
2349	{
2350	struct lsm_prop prop;
2351
2352	security_current_getlsmprop_subj(&prop);
2353	return audit_log_subj_ctx(ab, &prop);
2354	}
2355	EXPORT_SYMBOL(audit_log_task_context);
2356
2357	int audit_log_obj_ctx(struct audit_buffer ab, struct lsm_prop prop)
2358	{
2359	int i;
2360	int rc;
2361	int error = 0;
2362	char *space = "";
2363	struct lsm_context ctx;
2364
2365	if (audit_obj_secctx_cnt < 2) {
2366	error = security_lsmprop_to_secctx(prop, &ctx, LSM_ID_UNDEF);
2367	if (error < 0) {
2368	if (error != -EINVAL)
2369	goto error_path;
2370	return error;
2371	}
2372	audit_log_format(ab, " obj=%s", ctx.context);
2373	security_release_secctx(&ctx);
2374	return 0;
2375	}
2376	audit_log_format(ab, " obj=?");
2377	error = audit_buffer_aux_new(ab, AUDIT_MAC_OBJ_CONTEXTS);
2378	if (error)
2379	goto error_path;
2380
2381	for (i = 0; i < audit_obj_secctx_cnt; i++) {
2382	rc = security_lsmprop_to_secctx(prop, &ctx,
2383	audit_obj_lsms[i]->id);
2384	if (rc < 0) {
2385	audit_log_format(ab, "%sobj_%s=?", space,
2386	audit_obj_lsms[i]->name);
2387	if (rc != -EINVAL)
2388	audit_panic("error in audit_log_obj_ctx");
2389	error = rc;
2390	} else {
2391	audit_log_format(ab, "%sobj_%s=%s", space,
2392	audit_obj_lsms[i]->name, ctx.context);
2393	security_release_secctx(&ctx);
2394	}
2395	space = " ";
2396	}
2397
2398	audit_buffer_aux_end(ab);
2399	return error;
2400
2401	error_path:
2402	audit_panic("error in audit_log_obj_ctx");
2403	return error;
2404	}
2405
2406	void audit_log_d_path_exe(struct audit_buffer *ab,
2407	struct mm_struct *mm)
2408	{
2409	struct file *exe_file;
2410
2411	if (!mm)
2412	goto out_null;
2413
2414	exe_file = get_mm_exe_file(mm);
2415	if (!exe_file)
2416	goto out_null;
2417
2418	audit_log_d_path(ab, " exe=", &exe_file->f_path);
2419	fput(exe_file);
2420	return;
2421	out_null:
2422	audit_log_format(ab, " exe=(null)");
2423	}
2424
2425	struct tty_struct *audit_get_tty(void)
2426	{
2427	struct tty_struct *tty = NULL;
2428	unsigned long flags;
2429
2430	spin_lock_irqsave(&current->sighand->siglock, flags);
2431	if (current->signal)
2432	tty = tty_kref_get(current->signal->tty);
2433	spin_unlock_irqrestore(&current->sighand->siglock, flags);
2434	return tty;
2435	}
2436
2437	void audit_put_tty(struct tty_struct *tty)
2438	{
2439	tty_kref_put(tty);
2440	}
2441
2442	void audit_log_task_info(struct audit_buffer *ab)
2443	{
2444	const struct cred *cred;
2445	char comm[sizeof(current->comm)];
2446	struct tty_struct *tty;
2447
2448	if (!ab)
2449	return;
2450
2451	cred = current_cred();
2452	tty = audit_get_tty();
2453	audit_log_format(ab,
2454	" ppid=%d pid=%d auid=%u uid=%u gid=%u"
2455	" euid=%u suid=%u fsuid=%u"
2456	" egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
2457	task_ppid_nr(current),
2458	task_tgid_nr(current),
2459	from_kuid(&init_user_ns, audit_get_loginuid(current)),
2460	from_kuid(&init_user_ns, cred->uid),
2461	from_kgid(&init_user_ns, cred->gid),
2462	from_kuid(&init_user_ns, cred->euid),
2463	from_kuid(&init_user_ns, cred->suid),
2464	from_kuid(&init_user_ns, cred->fsuid),
2465	from_kgid(&init_user_ns, cred->egid),
2466	from_kgid(&init_user_ns, cred->sgid),
2467	from_kgid(&init_user_ns, cred->fsgid),
2468	tty ? tty_name(tty) : "(none)",
2469	audit_get_sessionid(current));
2470	audit_put_tty(tty);
2471	audit_log_format(ab, " comm=");
2472	audit_log_untrustedstring(ab, get_task_comm(comm, current));
2473	audit_log_d_path_exe(ab, current->mm);
2474	audit_log_task_context(ab);
2475	}
2476	EXPORT_SYMBOL(audit_log_task_info);
2477
2478	/**
2479	* audit_log_path_denied - report a path restriction denial
2480	* @type: audit message type (AUDIT_ANOM_LINK, AUDIT_ANOM_CREAT, etc)
2481	* @operation: specific operation name
2482	*/
2483	void audit_log_path_denied(int type, const char *operation)
2484	{
2485	struct audit_buffer *ab;
2486
2487	if (!audit_enabled)
2488	return;
2489
2490	/* Generate log with subject, operation, outcome. */
2491	ab = audit_log_start(audit_context(), GFP_KERNEL, type);
2492	if (!ab)
2493	return;
2494	audit_log_format(ab, "op=%s", operation);
2495	audit_log_task_info(ab);
2496	audit_log_format(ab, " res=0");
2497	audit_log_end(ab);
2498	}
2499
2500	int audit_log_nf_skb(struct audit_buffer *ab,
2501	const struct sk_buff *skb, u8 nfproto)
2502	{
2503	/* find the IP protocol in the case of NFPROTO_BRIDGE */
2504	if (nfproto == NFPROTO_BRIDGE) {
2505	switch (eth_hdr(skb)->h_proto) {
2506	case htons(ETH_P_IP):
2507	nfproto = NFPROTO_IPV4;
2508	break;
2509	case htons(ETH_P_IPV6):
2510	nfproto = NFPROTO_IPV6;
2511	break;
2512	default:
2513	goto unknown_proto;
2514	}
2515	}
2516
2517	switch (nfproto) {
2518	case NFPROTO_IPV4: {
2519	struct iphdr iph;
2520	const struct iphdr *ih;
2521
2522	ih = skb_header_pointer(skb, skb_network_offset(skb),
2523	sizeof(iph), &iph);
2524	if (!ih)
2525	return -ENOMEM;
2526
2527	switch (ih->protocol) {
2528	case IPPROTO_TCP: {
2529	struct tcphdr _tcph;
2530	const struct tcphdr *th;
2531
2532	th = skb_header_pointer(skb, skb_transport_offset(skb),
2533	sizeof(_tcph), &_tcph);
2534	if (!th)
2535	return -ENOMEM;
2536
2537	audit_log_format(ab, " saddr=%pI4 daddr=%pI4 proto=%hhu sport=%hu dport=%hu",
2538	&ih->saddr, &ih->daddr, ih->protocol,
2539	ntohs(th->source), ntohs(th->dest));
2540	break;
2541	}
2542	case IPPROTO_UDP:
2543	case IPPROTO_UDPLITE: {
2544	struct udphdr _udph;
2545	const struct udphdr *uh;
2546
2547	uh = skb_header_pointer(skb, skb_transport_offset(skb),
2548	sizeof(_udph), &_udph);
2549	if (!uh)
2550	return -ENOMEM;
2551
2552	audit_log_format(ab, " saddr=%pI4 daddr=%pI4 proto=%hhu sport=%hu dport=%hu",
2553	&ih->saddr, &ih->daddr, ih->protocol,
2554	ntohs(uh->source), ntohs(uh->dest));
2555	break;
2556	}
2557	case IPPROTO_SCTP: {
2558	struct sctphdr _sctph;
2559	const struct sctphdr *sh;
2560
2561	sh = skb_header_pointer(skb, skb_transport_offset(skb),
2562	sizeof(_sctph), &_sctph);
2563	if (!sh)
2564	return -ENOMEM;
2565
2566	audit_log_format(ab, " saddr=%pI4 daddr=%pI4 proto=%hhu sport=%hu dport=%hu",
2567	&ih->saddr, &ih->daddr, ih->protocol,
2568	ntohs(sh->source), ntohs(sh->dest));
2569	break;
2570	}
2571	default:
2572	audit_log_format(ab, " saddr=%pI4 daddr=%pI4 proto=%hhu",
2573	&ih->saddr, &ih->daddr, ih->protocol);
2574	}
2575
2576	break;
2577	}
2578	case NFPROTO_IPV6: {
2579	struct ipv6hdr iph;
2580	const struct ipv6hdr *ih;
2581	u8 nexthdr;
2582	__be16 frag_off;
2583
2584	ih = skb_header_pointer(skb, skb_network_offset(skb),
2585	sizeof(iph), &iph);
2586	if (!ih)
2587	return -ENOMEM;
2588
2589	nexthdr = ih->nexthdr;
2590	ipv6_skip_exthdr(skb, skb_network_offset(skb) + sizeof(iph),
2591	&nexthdr, &frag_off);
2592
2593	switch (nexthdr) {
2594	case IPPROTO_TCP: {
2595	struct tcphdr _tcph;
2596	const struct tcphdr *th;
2597
2598	th = skb_header_pointer(skb, skb_transport_offset(skb),
2599	sizeof(_tcph), &_tcph);
2600	if (!th)
2601	return -ENOMEM;
2602
2603	audit_log_format(ab, " saddr=%pI6c daddr=%pI6c proto=%hhu sport=%hu dport=%hu",
2604	&ih->saddr, &ih->daddr, nexthdr,
2605	ntohs(th->source), ntohs(th->dest));
2606	break;
2607	}
2608	case IPPROTO_UDP:
2609	case IPPROTO_UDPLITE: {
2610	struct udphdr _udph;
2611	const struct udphdr *uh;
2612
2613	uh = skb_header_pointer(skb, skb_transport_offset(skb),
2614	sizeof(_udph), &_udph);
2615	if (!uh)
2616	return -ENOMEM;
2617
2618	audit_log_format(ab, " saddr=%pI6c daddr=%pI6c proto=%hhu sport=%hu dport=%hu",
2619	&ih->saddr, &ih->daddr, nexthdr,
2620	ntohs(uh->source), ntohs(uh->dest));
2621	break;
2622	}
2623	case IPPROTO_SCTP: {
2624	struct sctphdr _sctph;
2625	const struct sctphdr *sh;
2626
2627	sh = skb_header_pointer(skb, skb_transport_offset(skb),
2628	sizeof(_sctph), &_sctph);
2629	if (!sh)
2630	return -ENOMEM;
2631
2632	audit_log_format(ab, " saddr=%pI6c daddr=%pI6c proto=%hhu sport=%hu dport=%hu",
2633	&ih->saddr, &ih->daddr, nexthdr,
2634	ntohs(sh->source), ntohs(sh->dest));
2635	break;
2636	}
2637	default:
2638	audit_log_format(ab, " saddr=%pI6c daddr=%pI6c proto=%hhu",
2639	&ih->saddr, &ih->daddr, nexthdr);
2640	}
2641
2642	break;
2643	}
2644	default:
2645	goto unknown_proto;
2646	}
2647
2648	return 0;
2649
2650	unknown_proto:
2651	audit_log_format(ab, " saddr=? daddr=? proto=?");
2652	return -EPFNOSUPPORT;
2653	}
2654	EXPORT_SYMBOL(audit_log_nf_skb);
2655
2656	/* global counter which is incremented every time something logs in */
2657	static atomic_t session_id = ATOMIC_INIT(0);
2658
2659	static int audit_set_loginuid_perm(kuid_t loginuid)
2660	{
2661	/* if we are unset, we don't need privs */
2662	if (!audit_loginuid_set(current))
2663	return 0;
2664	/* if AUDIT_FEATURE_LOGINUID_IMMUTABLE means never ever allow a change*/
2665	if (is_audit_feature_set(AUDIT_FEATURE_LOGINUID_IMMUTABLE))
2666	return -EPERM;
2667	/* it is set, you need permission */
2668	if (!capable(CAP_AUDIT_CONTROL))
2669	return -EPERM;
2670	/* reject if this is not an unset and we don't allow that */
2671	if (is_audit_feature_set(AUDIT_FEATURE_ONLY_UNSET_LOGINUID)
2672	&& uid_valid(loginuid))
2673	return -EPERM;
2674	return 0;
2675	}
2676
2677	static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
2678	unsigned int oldsessionid,
2679	unsigned int sessionid, int rc)
2680	{
2681	struct audit_buffer *ab;
2682	uid_t uid, oldloginuid, loginuid;
2683	struct tty_struct *tty;
2684
2685	if (!audit_enabled)
2686	return;
2687
2688	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_LOGIN);
2689	if (!ab)
2690	return;
2691
2692	uid = from_kuid(&init_user_ns, task_uid(current));
2693	oldloginuid = from_kuid(&init_user_ns, koldloginuid);
2694	loginuid = from_kuid(&init_user_ns, kloginuid);
2695	tty = audit_get_tty();
2696
2697	audit_log_format(ab, "pid=%d uid=%u", task_tgid_nr(current), uid);
2698	audit_log_task_context(ab);
2699	audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",
2700	oldloginuid, loginuid, tty ? tty_name(tty) : "(none)",
2701	oldsessionid, sessionid, !rc);
2702	audit_put_tty(tty);
2703	audit_log_end(ab);
2704	}
2705
2706	/**
2707	* audit_set_loginuid - set current task's loginuid
2708	* @loginuid: loginuid value
2709	*
2710	* Returns 0.
2711	*
2712	* Called (set) from fs/proc/base.c::proc_loginuid_write().
2713	*/
2714	int audit_set_loginuid(kuid_t loginuid)
2715	{
2716	unsigned int oldsessionid, sessionid = AUDIT_SID_UNSET;
2717	kuid_t oldloginuid;
2718	int rc;
2719
2720	oldloginuid = audit_get_loginuid(current);
2721	oldsessionid = audit_get_sessionid(current);
2722
2723	rc = audit_set_loginuid_perm(loginuid);
2724	if (rc)
2725	goto out;
2726
2727	/* are we setting or clearing? */
2728	if (uid_valid(loginuid)) {
2729	sessionid = (unsigned int)atomic_inc_return(&session_id);
2730	if (unlikely(sessionid == AUDIT_SID_UNSET))
2731	sessionid = (unsigned int)atomic_inc_return(&session_id);
2732	}
2733
2734	current->sessionid = sessionid;
2735	current->loginuid = loginuid;
2736	out:
2737	audit_log_set_loginuid(oldloginuid, loginuid, oldsessionid, sessionid, rc);
2738	return rc;
2739	}
2740
2741	/**
2742	* audit_signal_info - record signal info for shutting down audit subsystem
2743	* @sig: signal value
2744	* @t: task being signaled
2745	*
2746	* If the audit subsystem is being terminated, record the task (pid)
2747	* and uid that is doing that.
2748	*/
2749	int audit_signal_info(int sig, struct task_struct *t)
2750	{
2751	kuid_t uid = current_uid(), auid;
2752
2753	if (auditd_test_task(t) &&
2754	(sig == SIGTERM \|\| sig == SIGHUP \|\|
2755	sig == SIGUSR1 \|\| sig == SIGUSR2)) {
2756	audit_sig_pid = task_tgid_nr(current);
2757	auid = audit_get_loginuid(current);
2758	if (uid_valid(auid))
2759	audit_sig_uid = auid;
2760	else
2761	audit_sig_uid = uid;
2762	security_current_getlsmprop_subj(&audit_sig_lsm);
2763	}
2764
2765	return audit_signal_info_syscall(t);
2766	}
2767
2768	/**
2769	* __audit_log_end - enqueue one audit record
2770	* @skb: the buffer to send
2771	*/
2772	static void __audit_log_end(struct sk_buff *skb)
2773	{
2774	struct nlmsghdr *nlh;
2775
2776	if (audit_rate_check()) {
2777	/* setup the netlink header, see the comments in
2778	* kauditd_send_multicast_skb() for length quirks */
2779	nlh = nlmsg_hdr(skb);
2780	nlh->nlmsg_len = skb->len - NLMSG_HDRLEN;
2781
2782	/* queue the netlink packet */
2783	skb_queue_tail(&audit_queue, skb);
2784	} else {
2785	audit_log_lost("rate limit exceeded");
2786	kfree_skb(skb);
2787	}
2788	}
2789
2790	/**
2791	* audit_log_end - end one audit record
2792	* @ab: the audit_buffer
2793	*
2794	* We can not do a netlink send inside an irq context because it blocks (last
2795	* arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a
2796	* queue and a kthread is scheduled to remove them from the queue outside the
2797	* irq context. May be called in any context.
2798	*/
2799	void audit_log_end(struct audit_buffer *ab)
2800	{
2801	struct sk_buff *skb;
2802
2803	if (!ab)
2804	return;
2805
2806	while ((skb = skb_dequeue(&ab->skb_list)))
2807	__audit_log_end(skb);
2808
2809	/* poke the kauditd thread */
2810	wake_up_interruptible(&kauditd_wait);
2811
2812	audit_buffer_free(ab);
2813	}
2814
2815	/**
2816	* audit_log - Log an audit record
2817	* @ctx: audit context
2818	* @gfp_mask: type of allocation
2819	* @type: audit message type
2820	* @fmt: format string to use
2821	* @...: variable parameters matching the format string
2822	*
2823	* This is a convenience function that calls audit_log_start,
2824	* audit_log_vformat, and audit_log_end. It may be called
2825	* in any context.
2826	*/
2827	void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
2828	const char *fmt, ...)
2829	{
2830	struct audit_buffer *ab;
2831	va_list args;
2832
2833	ab = audit_log_start(ctx, gfp_mask, type);
2834	if (ab) {
2835	va_start(args, fmt);
2836	audit_log_vformat(ab, fmt, args);
2837	va_end(args);
2838	audit_log_end(ab);
2839	}
2840	}
2841
2842	EXPORT_SYMBOL(audit_log_start);
2843	EXPORT_SYMBOL(audit_log_end);
2844	EXPORT_SYMBOL(audit_log_format);
2845	EXPORT_SYMBOL(audit_log);