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 <faith@redhat.com>
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/init.h>
36	#include <linux/types.h>
37	#include <linux/atomic.h>
38	#include <linux/mm.h>
39	#include <linux/export.h>
40	#include <linux/slab.h>
41	#include <linux/err.h>
42	#include <linux/kthread.h>
43	#include <linux/kernel.h>
44	#include <linux/syscalls.h>
45	#include <linux/spinlock.h>
46	#include <linux/rcupdate.h>
47	#include <linux/mutex.h>
48	#include <linux/gfp.h>
49	#include <linux/pid.h>
50
51	#include <linux/audit.h>
52
53	#include <net/sock.h>
54	#include <net/netlink.h>
55	#include <linux/skbuff.h>
56	#include <linux/security.h>
57	#include <linux/freezer.h>
58	#include <linux/pid_namespace.h>
59	#include <net/netns/generic.h>
60
61	#include "audit.h"
62
63	/* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
64	* (Initialization happens after skb_init is called.) */
65	#define AUDIT_DISABLED -1
66	#define AUDIT_UNINITIALIZED 0
67	#define AUDIT_INITIALIZED 1
68	static int audit_initialized = AUDIT_UNINITIALIZED;
69
70	u32 audit_enabled = AUDIT_OFF;
71	bool audit_ever_enabled = !!AUDIT_OFF;
72
73	EXPORT_SYMBOL_GPL(audit_enabled);
74
75	/* Default state when kernel boots without any parameters. */
76	static u32 audit_default = AUDIT_OFF;
77
78	/* If auditing cannot proceed, audit_failure selects what happens. */
79	static u32 audit_failure = AUDIT_FAIL_PRINTK;
80
81	/* private audit network namespace index */
82	static unsigned int audit_net_id;
83
84	/**
85	* struct audit_net - audit private network namespace data
86	* @sk: communication socket
87	*/
88	struct audit_net {
89	struct sock *sk;
90	};
91
92	/**
93	* struct auditd_connection - kernel/auditd connection state
94	* @pid: auditd PID
95	* @portid: netlink portid
96	* @net: the associated network namespace
97	* @rcu: RCU head
98	*
99	* Description:
100	* This struct is RCU protected; you must either hold the RCU lock for reading
101	* or the associated spinlock for writing.
102	*/
103	struct auditd_connection {
104	struct pid *pid;
105	u32 portid;
106	struct net *net;
107	struct rcu_head rcu;
108	};
109	static struct auditd_connection __rcu *auditd_conn;
110	static DEFINE_SPINLOCK(auditd_conn_lock);
111
112	/* If audit_rate_limit is non-zero, limit the rate of sending audit records
113	* to that number per second. This prevents DoS attacks, but results in
114	* audit records being dropped. */
115	static u32 audit_rate_limit;
116
117	/* Number of outstanding audit_buffers allowed.
118	* When set to zero, this means unlimited. */
119	static u32 audit_backlog_limit = 64;
120	#define AUDIT_BACKLOG_WAIT_TIME (60 * HZ)
121	static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
122
123	/* The identity of the user shutting down the audit system. */
124	static kuid_t audit_sig_uid = INVALID_UID;
125	static pid_t audit_sig_pid = -1;
126	static u32 audit_sig_sid;
127
128	/* Records can be lost in several ways:
129	0) [suppressed in audit_alloc]
130	1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
131	2) out of memory in audit_log_move [alloc_skb]
132	3) suppressed due to audit_rate_limit
133	4) suppressed due to audit_backlog_limit
134	*/
135	static atomic_t audit_lost = ATOMIC_INIT(0);
136
137	/* Monotonically increasing sum of time the kernel has spent
138	* waiting while the backlog limit is exceeded.
139	*/
140	static atomic_t audit_backlog_wait_time_actual = ATOMIC_INIT(0);
141
142	/* Hash for inode-based rules */
143	struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
144
145	static struct kmem_cache *audit_buffer_cache;
146
147	/* queue msgs to send via kauditd_task */
148	static struct sk_buff_head audit_queue;
149	/* queue msgs due to temporary unicast send problems */
150	static struct sk_buff_head audit_retry_queue;
151	/* queue msgs waiting for new auditd connection */
152	static struct sk_buff_head audit_hold_queue;
153
154	/* queue servicing thread */
155	static struct task_struct *kauditd_task;
156	static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
157
158	/* waitqueue for callers who are blocked on the audit backlog */
159	static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
160
161	static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION,
162	.mask = -1,
163	.features = 0,
164	.lock = 0,};
165
166	static char *audit_feature_names[2] = {
167	"only_unset_loginuid",
168	"loginuid_immutable",
169	};
170
171	/**
172	* struct audit_ctl_mutex - serialize requests from userspace
173	* @lock: the mutex used for locking
174	* @owner: the task which owns the lock
175	*
176	* Description:
177	* This is the lock struct used to ensure we only process userspace requests
178	* in an orderly fashion. We can't simply use a mutex/lock here because we
179	* need to track lock ownership so we don't end up blocking the lock owner in
180	* audit_log_start() or similar.
181	*/
182	static struct audit_ctl_mutex {
183	struct mutex lock;
184	void *owner;
185	} audit_cmd_mutex;
186
187	/* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
188	* audit records. Since printk uses a 1024 byte buffer, this buffer
189	* should be at least that large. */
190	#define AUDIT_BUFSIZ 1024
191
192	/* The audit_buffer is used when formatting an audit record. The caller
193	* locks briefly to get the record off the freelist or to allocate the
194	* buffer, and locks briefly to send the buffer to the netlink layer or
195	* to place it on a transmit queue. Multiple audit_buffers can be in
196	* use simultaneously. */
197	struct audit_buffer {
198	struct sk_buff *skb; /* formatted skb ready to send */
199	struct audit_context *ctx; /* NULL or associated context */
200	gfp_t gfp_mask;
201	};
202
203	struct audit_reply {
204	__u32 portid;
205	struct net *net;
206	struct sk_buff *skb;
207	};
208
209	/**
210	* auditd_test_task - Check to see if a given task is an audit daemon
211	* @task: the task to check
212	*
213	* Description:
214	* Return 1 if the task is a registered audit daemon, 0 otherwise.
215	*/
216	int auditd_test_task(struct task_struct *task)
217	{
218	int rc;
219	struct auditd_connection *ac;
220
221	rcu_read_lock();
222	ac = rcu_dereference(auditd_conn);
223	rc = (ac && ac->pid == task_tgid(task) ? 1 : 0);
224	rcu_read_unlock();
225
226	return rc;
227	}
228
229	/**
230	* audit_ctl_lock - Take the audit control lock
231	*/
232	void audit_ctl_lock(void)
233	{
234	mutex_lock(&audit_cmd_mutex.lock);
235	audit_cmd_mutex.owner = current;
236	}
237
238	/**
239	* audit_ctl_unlock - Drop the audit control lock
240	*/
241	void audit_ctl_unlock(void)
242	{
243	audit_cmd_mutex.owner = NULL;
244	mutex_unlock(lock: &audit_cmd_mutex.lock);
245	}
246
247	/**
248	* audit_ctl_owner_current - Test to see if the current task owns the lock
249	*
250	* Description:
251	* Return true if the current task owns the audit control lock, false if it
252	* doesn't own the lock.
253	*/
254	static bool audit_ctl_owner_current(void)
255	{
256	return (current == audit_cmd_mutex.owner);
257	}
258
259	/**
260	* auditd_pid_vnr - Return the auditd PID relative to the namespace
261	*
262	* Description:
263	* Returns the PID in relation to the namespace, 0 on failure.
264	*/
265	static pid_t auditd_pid_vnr(void)
266	{
267	pid_t pid;
268	const struct auditd_connection *ac;
269
270	rcu_read_lock();
271	ac = rcu_dereference(auditd_conn);
272	if (!ac || !ac->pid)
273	pid = 0;
274	else
275	pid = pid_vnr(pid: ac->pid);
276	rcu_read_unlock();
277
278	return pid;
279	}
280
281	/**
282	* audit_get_sk - Return the audit socket for the given network namespace
283	* @net: the destination network namespace
284	*
285	* Description:
286	* Returns the sock pointer if valid, NULL otherwise. The caller must ensure
287	* that a reference is held for the network namespace while the sock is in use.
288	*/
289	static struct sock *audit_get_sk(const struct net *net)
290	{
291	struct audit_net *aunet;
292
293	if (!net)
294	return NULL;
295
296	aunet = net_generic(net, id: audit_net_id);
297	return aunet->sk;
298	}
299
300	void audit_panic(const char *message)
301	{
302	switch (audit_failure) {
303	case AUDIT_FAIL_SILENT:
304	break;
305	case AUDIT_FAIL_PRINTK:
306	if (printk_ratelimit())
307	pr_err("%s\n", message);
308	break;
309	case AUDIT_FAIL_PANIC:
310	panic(fmt: "audit: %s\n", message);
311	break;
312	}
313	}
314
315	static inline int audit_rate_check(void)
316	{
317	static unsigned long last_check = 0;
318	static int messages = 0;
319	static DEFINE_SPINLOCK(lock);
320	unsigned long flags;
321	unsigned long now;
322	int retval = 0;
323
324	if (!audit_rate_limit)
325	return 1;
326
327	spin_lock_irqsave(&lock, flags);
328	if (++messages < audit_rate_limit) {
329	retval = 1;
330	} else {
331	now = jiffies;
332	if (time_after(now, last_check + HZ)) {
333	last_check = now;
334	messages = 0;
335	retval = 1;
336	}
337	}
338	spin_unlock_irqrestore(lock: &lock, flags);
339
340	return retval;
341	}
342
343	/**
344	* audit_log_lost - conditionally log lost audit message event
345	* @message: the message stating reason for lost audit message
346	*
347	* Emit at least 1 message per second, even if audit_rate_check is
348	* throttling.
349	* Always increment the lost messages counter.
350	*/
351	void audit_log_lost(const char *message)
352	{
353	static unsigned long last_msg = 0;
354	static DEFINE_SPINLOCK(lock);
355	unsigned long flags;
356	unsigned long now;
357	int print;
358
359	atomic_inc(v: &audit_lost);
360
361	print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
362
363	if (!print) {
364	spin_lock_irqsave(&lock, flags);
365	now = jiffies;
366	if (time_after(now, last_msg + HZ)) {
367	print = 1;
368	last_msg = now;
369	}
370	spin_unlock_irqrestore(lock: &lock, flags);
371	}
372
373	if (print) {
374	if (printk_ratelimit())
375	pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
376	atomic_read(&audit_lost),
377	audit_rate_limit,
378	audit_backlog_limit);
379	audit_panic(message);
380	}
381	}
382
383	static int audit_log_config_change(char *function_name, u32 new, u32 old,
384	int allow_changes)
385	{
386	struct audit_buffer *ab;
387	int rc = 0;
388
389	ab = audit_log_start(ctx: audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
390	if (unlikely(!ab))
391	return rc;
392	audit_log_format(ab, fmt: "op=set %s=%u old=%u ", function_name, new, old);
393	audit_log_session_info(ab);
394	rc = audit_log_task_context(ab);
395	if (rc)
396	allow_changes = 0; /* Something weird, deny request */
397	audit_log_format(ab, fmt: " res=%d", allow_changes);
398	audit_log_end(ab);
399	return rc;
400	}
401
402	static int audit_do_config_change(char *function_name, u32 *to_change, u32 new)
403	{
404	int allow_changes, rc = 0;
405	u32 old = *to_change;
406
407	/* check if we are locked */
408	if (audit_enabled == AUDIT_LOCKED)
409	allow_changes = 0;
410	else
411	allow_changes = 1;
412
413	if (audit_enabled != AUDIT_OFF) {
414	rc = audit_log_config_change(function_name, new, old, allow_changes);
415	if (rc)
416	allow_changes = 0;
417	}
418
419	/* If we are allowed, make the change */
420	if (allow_changes == 1)
421	*to_change = new;
422	/* Not allowed, update reason */
423	else if (rc == 0)
424	rc = -EPERM;
425	return rc;
426	}
427
428	static int audit_set_rate_limit(u32 limit)
429	{
430	return audit_do_config_change(function_name: "audit_rate_limit", to_change: &audit_rate_limit, new: limit);
431	}
432
433	static int audit_set_backlog_limit(u32 limit)
434	{
435	return audit_do_config_change(function_name: "audit_backlog_limit", to_change: &audit_backlog_limit, new: limit);
436	}
437
438	static int audit_set_backlog_wait_time(u32 timeout)
439	{
440	return audit_do_config_change(function_name: "audit_backlog_wait_time",
441	to_change: &audit_backlog_wait_time, new: timeout);
442	}
443
444	static int audit_set_enabled(u32 state)
445	{
446	int rc;
447	if (state > AUDIT_LOCKED)
448	return -EINVAL;
449
450	rc = audit_do_config_change(function_name: "audit_enabled", to_change: &audit_enabled, new: state);
451	if (!rc)
452	audit_ever_enabled |= !!state;
453
454	return rc;
455	}
456
457	static int audit_set_failure(u32 state)
458	{
459	if (state != AUDIT_FAIL_SILENT
460	&& state != AUDIT_FAIL_PRINTK
461	&& state != AUDIT_FAIL_PANIC)
462	return -EINVAL;
463
464	return audit_do_config_change(function_name: "audit_failure", to_change: &audit_failure, new: state);
465	}
466
467	/**
468	* auditd_conn_free - RCU helper to release an auditd connection struct
469	* @rcu: RCU head
470	*
471	* Description:
472	* Drop any references inside the auditd connection tracking struct and free
473	* the memory.
474	*/
475	static void auditd_conn_free(struct rcu_head *rcu)
476	{
477	struct auditd_connection *ac;
478
479	ac = container_of(rcu, struct auditd_connection, rcu);
480	put_pid(pid: ac->pid);
481	put_net(net: ac->net);
482	kfree(objp: ac);
483	}
484
485	/**
486	* auditd_set - Set/Reset the auditd connection state
487	* @pid: auditd PID
488	* @portid: auditd netlink portid
489	* @net: auditd network namespace pointer
490	*
491	* Description:
492	* This function will obtain and drop network namespace references as
493	* necessary. Returns zero on success, negative values on failure.
494	*/
495	static int auditd_set(struct pid *pid, u32 portid, struct net *net)
496	{
497	unsigned long flags;
498	struct auditd_connection *ac_old, *ac_new;
499
500	if (!pid || !net)
501	return -EINVAL;
502
503	ac_new = kzalloc(size: sizeof(*ac_new), GFP_KERNEL);
504	if (!ac_new)
505	return -ENOMEM;
506	ac_new->pid = get_pid(pid);
507	ac_new->portid = portid;
508	ac_new->net = get_net(net);
509
510	spin_lock_irqsave(&auditd_conn_lock, flags);
511	ac_old = rcu_dereference_protected(auditd_conn,
512	lockdep_is_held(&auditd_conn_lock));
513	rcu_assign_pointer(auditd_conn, ac_new);
514	spin_unlock_irqrestore(lock: &auditd_conn_lock, flags);
515
516	if (ac_old)
517	call_rcu(head: &ac_old->rcu, func: auditd_conn_free);
518
519	return 0;
520	}
521
522	/**
523	* kauditd_printk_skb - Print the audit record to the ring buffer
524	* @skb: audit record
525	*
526	* Whatever the reason, this packet may not make it to the auditd connection
527	* so write it via printk so the information isn't completely lost.
528	*/
529	static void kauditd_printk_skb(struct sk_buff *skb)
530	{
531	struct nlmsghdr *nlh = nlmsg_hdr(skb);
532	char *data = nlmsg_data(nlh);
533
534	if (nlh->nlmsg_type != AUDIT_EOE && printk_ratelimit())
535	pr_notice("type=%d %s\n", nlh->nlmsg_type, data);
536	}
537
538	/**
539	* kauditd_rehold_skb - Handle a audit record send failure in the hold queue
540	* @skb: audit record
541	* @error: error code (unused)
542	*
543	* Description:
544	* This should only be used by the kauditd_thread when it fails to flush the
545	* hold queue.
546	*/
547	static void kauditd_rehold_skb(struct sk_buff *skb, __always_unused int error)
548	{
549	/* put the record back in the queue */
550	skb_queue_tail(list: &audit_hold_queue, newsk: skb);
551	}
552
553	/**
554	* kauditd_hold_skb - Queue an audit record, waiting for auditd
555	* @skb: audit record
556	* @error: error code
557	*
558	* Description:
559	* Queue the audit record, waiting for an instance of auditd. When this
560	* function is called we haven't given up yet on sending the record, but things
561	* are not looking good. The first thing we want to do is try to write the
562	* record via printk and then see if we want to try and hold on to the record
563	* and queue it, if we have room. If we want to hold on to the record, but we
564	* don't have room, record a record lost message.
565	*/
566	static void kauditd_hold_skb(struct sk_buff *skb, int error)
567	{
568	/* at this point it is uncertain if we will ever send this to auditd so
569	* try to send the message via printk before we go any further */
570	kauditd_printk_skb(skb);
571
572	/* can we just silently drop the message? */
573	if (!audit_default)
574	goto drop;
575
576	/* the hold queue is only for when the daemon goes away completely,
577	* not -EAGAIN failures; if we are in a -EAGAIN state requeue the
578	* record on the retry queue unless it's full, in which case drop it
579	*/
580	if (error == -EAGAIN) {
581	if (!audit_backlog_limit ||
582	skb_queue_len(list_: &audit_retry_queue) < audit_backlog_limit) {
583	skb_queue_tail(list: &audit_retry_queue, newsk: skb);
584	return;
585	}
586	audit_log_lost(message: "kauditd retry queue overflow");
587	goto drop;
588	}
589
590	/* if we have room in the hold queue, queue the message */
591	if (!audit_backlog_limit ||
592	skb_queue_len(list_: &audit_hold_queue) < audit_backlog_limit) {
593	skb_queue_tail(list: &audit_hold_queue, newsk: skb);
594	return;
595	}
596
597	/* we have no other options - drop the message */
598	audit_log_lost(message: "kauditd hold queue overflow");
599	drop:
600	kfree_skb(skb);
601	}
602
603	/**
604	* kauditd_retry_skb - Queue an audit record, attempt to send again to auditd
605	* @skb: audit record
606	* @error: error code (unused)
607	*
608	* Description:
609	* Not as serious as kauditd_hold_skb() as we still have a connected auditd,
610	* but for some reason we are having problems sending it audit records so
611	* queue the given record and attempt to resend.
612	*/
613	static void kauditd_retry_skb(struct sk_buff *skb, __always_unused int error)
614	{
615	if (!audit_backlog_limit ||
616	skb_queue_len(list_: &audit_retry_queue) < audit_backlog_limit) {
617	skb_queue_tail(list: &audit_retry_queue, newsk: skb);
618	return;
619	}
620
621	/* we have to drop the record, send it via printk as a last effort */
622	kauditd_printk_skb(skb);
623	audit_log_lost(message: "kauditd retry queue overflow");
624	kfree_skb(skb);
625	}
626
627	/**
628	* auditd_reset - Disconnect the auditd connection
629	* @ac: auditd connection state
630	*
631	* Description:
632	* Break the auditd/kauditd connection and move all the queued records into the
633	* hold queue in case auditd reconnects. It is important to note that the @ac
634	* pointer should never be dereferenced inside this function as it may be NULL
635	* or invalid, you can only compare the memory address! If @ac is NULL then
636	* the connection will always be reset.
637	*/
638	static void auditd_reset(const struct auditd_connection *ac)
639	{
640	unsigned long flags;
641	struct sk_buff *skb;
642	struct auditd_connection *ac_old;
643
644	/* if it isn't already broken, break the connection */
645	spin_lock_irqsave(&auditd_conn_lock, flags);
646	ac_old = rcu_dereference_protected(auditd_conn,
647	lockdep_is_held(&auditd_conn_lock));
648	if (ac && ac != ac_old) {
649	/* someone already registered a new auditd connection */
650	spin_unlock_irqrestore(lock: &auditd_conn_lock, flags);
651	return;
652	}
653	rcu_assign_pointer(auditd_conn, NULL);
654	spin_unlock_irqrestore(lock: &auditd_conn_lock, flags);
655
656	if (ac_old)
657	call_rcu(head: &ac_old->rcu, func: auditd_conn_free);
658
659	/* flush the retry queue to the hold queue, but don't touch the main
660	* queue since we need to process that normally for multicast */
661	while ((skb = skb_dequeue(list: &audit_retry_queue)))
662	kauditd_hold_skb(skb, error: -ECONNREFUSED);
663	}
664
665	/**
666	* auditd_send_unicast_skb - Send a record via unicast to auditd
667	* @skb: audit record
668	*
669	* Description:
670	* Send a skb to the audit daemon, returns positive/zero values on success and
671	* negative values on failure; in all cases the skb will be consumed by this
672	* function. If the send results in -ECONNREFUSED the connection with auditd
673	* will be reset. This function may sleep so callers should not hold any locks
674	* where this would cause a problem.
675	*/
676	static int auditd_send_unicast_skb(struct sk_buff *skb)
677	{
678	int rc;
679	u32 portid;
680	struct net *net;
681	struct sock *sk;
682	struct auditd_connection *ac;
683
684	/* NOTE: we can't call netlink_unicast while in the RCU section so
685	* take a reference to the network namespace and grab local
686	* copies of the namespace, the sock, and the portid; the
687	* namespace and sock aren't going to go away while we hold a
688	* reference and if the portid does become invalid after the RCU
689	* section netlink_unicast() should safely return an error */
690
691	rcu_read_lock();
692	ac = rcu_dereference(auditd_conn);
693	if (!ac) {
694	rcu_read_unlock();
695	kfree_skb(skb);
696	rc = -ECONNREFUSED;
697	goto err;
698	}
699	net = get_net(net: ac->net);
700	sk = audit_get_sk(net);
701	portid = ac->portid;
702	rcu_read_unlock();
703
704	rc = netlink_unicast(ssk: sk, skb, portid, nonblock: 0);
705	put_net(net);
706	if (rc < 0)
707	goto err;
708
709	return rc;
710
711	err:
712	if (ac && rc == -ECONNREFUSED)
713	auditd_reset(ac);
714	return rc;
715	}
716
717	/**
718	* kauditd_send_queue - Helper for kauditd_thread to flush skb queues
719	* @sk: the sending sock
720	* @portid: the netlink destination
721	* @queue: the skb queue to process
722	* @retry_limit: limit on number of netlink unicast failures
723	* @skb_hook: per-skb hook for additional processing
724	* @err_hook: hook called if the skb fails the netlink unicast send
725	*
726	* Description:
727	* Run through the given queue and attempt to send the audit records to auditd,
728	* returns zero on success, negative values on failure. It is up to the caller
729	* to ensure that the @sk is valid for the duration of this function.
730	*
731	*/
732	static int kauditd_send_queue(struct sock *sk, u32 portid,
733	struct sk_buff_head *queue,
734	unsigned int retry_limit,
735	void (*skb_hook)(struct sk_buff *skb),
736	void (*err_hook)(struct sk_buff *skb, int error))
737	{
738	int rc = 0;
739	struct sk_buff *skb = NULL;
740	struct sk_buff *skb_tail;
741	unsigned int failed = 0;
742
743	/* NOTE: kauditd_thread takes care of all our locking, we just use
744	* the netlink info passed to us (e.g. sk and portid) */
745
746	skb_tail = skb_peek_tail(list_: queue);
747	while ((skb != skb_tail) && (skb = skb_dequeue(list: queue))) {
748	/* call the skb_hook for each skb we touch */
749	if (skb_hook)
750	(*skb_hook)(skb);
751
752	/* can we send to anyone via unicast? */
753	if (!sk) {
754	if (err_hook)
755	(*err_hook)(skb, -ECONNREFUSED);
756	continue;
757	}
758
759	retry:
760	/* grab an extra skb reference in case of error */
761	skb_get(skb);
762	rc = netlink_unicast(ssk: sk, skb, portid, nonblock: 0);
763	if (rc < 0) {
764	/* send failed - try a few times unless fatal error */
765	if (++failed >= retry_limit ||
766	rc == -ECONNREFUSED || rc == -EPERM) {
767	sk = NULL;
768	if (err_hook)
769	(*err_hook)(skb, rc);
770	if (rc == -EAGAIN)
771	rc = 0;
772	/* continue to drain the queue */
773	continue;
774	} else
775	goto retry;
776	} else {
777	/* skb sent - drop the extra reference and continue */
778	consume_skb(skb);
779	failed = 0;
780	}
781	}
782
783	return (rc >= 0 ? 0 : rc);
784	}
785
786	/*
787	* kauditd_send_multicast_skb - Send a record to any multicast listeners
788	* @skb: audit record
789	*
790	* Description:
791	* Write a multicast message to anyone listening in the initial network
792	* namespace. This function doesn't consume an skb as might be expected since
793	* it has to copy it anyways.
794	*/
795	static void kauditd_send_multicast_skb(struct sk_buff *skb)
796	{
797	struct sk_buff *copy;
798	struct sock *sock = audit_get_sk(net: &init_net);
799	struct nlmsghdr *nlh;
800
801	/* NOTE: we are not taking an additional reference for init_net since
802	* we don't have to worry about it going away */
803
804	if (!netlink_has_listeners(sk: sock, group: AUDIT_NLGRP_READLOG))
805	return;
806
807	/*
808	* The seemingly wasteful skb_copy() rather than bumping the refcount
809	* using skb_get() is necessary because non-standard mods are made to
810	* the skb by the original kaudit unicast socket send routine. The
811	* existing auditd daemon assumes this breakage. Fixing this would
812	* require co-ordinating a change in the established protocol between
813	* the kaudit kernel subsystem and the auditd userspace code. There is
814	* no reason for new multicast clients to continue with this
815	* non-compliance.
816	*/
817	copy = skb_copy(skb, GFP_KERNEL);
818	if (!copy)
819	return;
820	nlh = nlmsg_hdr(skb: copy);
821	nlh->nlmsg_len = skb->len;
822
823	nlmsg_multicast(sk: sock, skb: copy, portid: 0, group: AUDIT_NLGRP_READLOG, GFP_KERNEL);
824	}
825
826	/**
827	* kauditd_thread - Worker thread to send audit records to userspace
828	* @dummy: unused
829	*/
830	static int kauditd_thread(void *dummy)
831	{
832	int rc;
833	u32 portid = 0;
834	struct net *net = NULL;
835	struct sock *sk = NULL;
836	struct auditd_connection *ac;
837
838	#define UNICAST_RETRIES 5
839
840	set_freezable();
841	while (!kthread_should_stop()) {
842	/* NOTE: see the lock comments in auditd_send_unicast_skb() */
843	rcu_read_lock();
844	ac = rcu_dereference(auditd_conn);
845	if (!ac) {
846	rcu_read_unlock();
847	goto main_queue;
848	}
849	net = get_net(net: ac->net);
850	sk = audit_get_sk(net);
851	portid = ac->portid;
852	rcu_read_unlock();
853
854	/* attempt to flush the hold queue */
855	rc = kauditd_send_queue(sk, portid,
856	queue: &audit_hold_queue, UNICAST_RETRIES,
857	NULL, err_hook: kauditd_rehold_skb);
858	if (rc < 0) {
859	sk = NULL;
860	auditd_reset(ac);
861	goto main_queue;
862	}
863
864	/* attempt to flush the retry queue */
865	rc = kauditd_send_queue(sk, portid,
866	queue: &audit_retry_queue, UNICAST_RETRIES,
867	NULL, err_hook: kauditd_hold_skb);
868	if (rc < 0) {
869	sk = NULL;
870	auditd_reset(ac);
871	goto main_queue;
872	}
873
874	main_queue:
875	/* process the main queue - do the multicast send and attempt
876	* unicast, dump failed record sends to the retry queue; if
877	* sk == NULL due to previous failures we will just do the
878	* multicast send and move the record to the hold queue */
879	rc = kauditd_send_queue(sk, portid, queue: &audit_queue, retry_limit: 1,
880	skb_hook: kauditd_send_multicast_skb,
881	err_hook: (sk ?
882	kauditd_retry_skb : kauditd_hold_skb));
883	if (ac && rc < 0)
884	auditd_reset(ac);
885	sk = NULL;
886
887	/* drop our netns reference, no auditd sends past this line */
888	if (net) {
889	put_net(net);
890	net = NULL;
891	}
892
893	/* we have processed all the queues so wake everyone */
894	wake_up(&audit_backlog_wait);
895
896	/* NOTE: we want to wake up if there is anything on the queue,
897	* regardless of if an auditd is connected, as we need to
898	* do the multicast send and rotate records from the
899	* main queue to the retry/hold queues */
900	wait_event_freezable(kauditd_wait,
901	(skb_queue_len(&audit_queue) ? 1 : 0));
902	}
903
904	return 0;
905	}
906
907	int audit_send_list_thread(void *_dest)
908	{
909	struct audit_netlink_list *dest = _dest;
910	struct sk_buff *skb;
911	struct sock *sk = audit_get_sk(net: dest->net);
912
913	/* wait for parent to finish and send an ACK */
914	audit_ctl_lock();
915	audit_ctl_unlock();
916
917	while ((skb = __skb_dequeue(list: &dest->q)) != NULL)
918	netlink_unicast(ssk: sk, skb, portid: dest->portid, nonblock: 0);
919
920	put_net(net: dest->net);
921	kfree(objp: dest);
922
923	return 0;
924	}
925
926	struct sk_buff *audit_make_reply(int seq, int type, int done,
927	int multi, const void *payload, int size)
928	{
929	struct sk_buff *skb;
930	struct nlmsghdr *nlh;
931	void *data;
932	int flags = multi ? NLM_F_MULTI : 0;
933	int t = done ? NLMSG_DONE : type;
934
935	skb = nlmsg_new(payload: size, GFP_KERNEL);
936	if (!skb)
937	return NULL;
938
939	nlh = nlmsg_put(skb, portid: 0, seq, type: t, payload: size, flags);
940	if (!nlh)
941	goto out_kfree_skb;
942	data = nlmsg_data(nlh);
943	memcpy(data, payload, size);
944	return skb;
945
946	out_kfree_skb:
947	kfree_skb(skb);
948	return NULL;
949	}
950
951	static void audit_free_reply(struct audit_reply *reply)
952	{
953	if (!reply)
954	return;
955
956	kfree_skb(skb: reply->skb);
957	if (reply->net)
958	put_net(net: reply->net);
959	kfree(objp: reply);
960	}
961
962	static int audit_send_reply_thread(void *arg)
963	{
964	struct audit_reply *reply = (struct audit_reply *)arg;
965
966	audit_ctl_lock();
967	audit_ctl_unlock();
968
969	/* Ignore failure. It'll only happen if the sender goes away,
970	because our timeout is set to infinite. */
971	netlink_unicast(ssk: audit_get_sk(net: reply->net), skb: reply->skb, portid: reply->portid, nonblock: 0);
972	reply->skb = NULL;
973	audit_free_reply(reply);
974	return 0;
975	}
976
977	/**
978	* audit_send_reply - send an audit reply message via netlink
979	* @request_skb: skb of request we are replying to (used to target the reply)
980	* @seq: sequence number
981	* @type: audit message type
982	* @done: done (last) flag
983	* @multi: multi-part message flag
984	* @payload: payload data
985	* @size: payload size
986	*
987	* Allocates a skb, builds the netlink message, and sends it to the port id.
988	*/
989	static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
990	int multi, const void *payload, int size)
991	{
992	struct task_struct *tsk;
993	struct audit_reply *reply;
994
995	reply = kzalloc(size: sizeof(*reply), GFP_KERNEL);
996	if (!reply)
997	return;
998
999	reply->skb = audit_make_reply(seq, type, done, multi, payload, size);
1000	if (!reply->skb)
1001	goto err;
1002	reply->net = get_net(net: sock_net(NETLINK_CB(request_skb).sk));
1003	reply->portid = NETLINK_CB(request_skb).portid;
1004
1005	tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
1006	if (IS_ERR(ptr: tsk))
1007	goto err;
1008
1009	return;
1010
1011	err:
1012	audit_free_reply(reply);
1013	}
1014
1015	/*
1016	* Check for appropriate CAP_AUDIT_ capabilities on incoming audit
1017	* control messages.
1018	*/
1019	static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
1020	{
1021	int err = 0;
1022
1023	/* Only support initial user namespace for now. */
1024	/*
1025	* We return ECONNREFUSED because it tricks userspace into thinking
1026	* that audit was not configured into the kernel. Lots of users
1027	* configure their PAM stack (because that's what the distro does)
1028	* to reject login if unable to send messages to audit. If we return
1029	* ECONNREFUSED the PAM stack thinks the kernel does not have audit
1030	* configured in and will let login proceed. If we return EPERM
1031	* userspace will reject all logins. This should be removed when we
1032	* support non init namespaces!!
1033	*/
1034	if (current_user_ns() != &init_user_ns)
1035	return -ECONNREFUSED;
1036
1037	switch (msg_type) {
1038	case AUDIT_LIST:
1039	case AUDIT_ADD:
1040	case AUDIT_DEL:
1041	return -EOPNOTSUPP;
1042	case AUDIT_GET:
1043	case AUDIT_SET:
1044	case AUDIT_GET_FEATURE:
1045	case AUDIT_SET_FEATURE:
1046	case AUDIT_LIST_RULES:
1047	case AUDIT_ADD_RULE:
1048	case AUDIT_DEL_RULE:
1049	case AUDIT_SIGNAL_INFO:
1050	case AUDIT_TTY_GET:
1051	case AUDIT_TTY_SET:
1052	case AUDIT_TRIM:
1053	case AUDIT_MAKE_EQUIV:
1054	/* Only support auditd and auditctl in initial pid namespace
1055	* for now. */
1056	if (task_active_pid_ns(current) != &init_pid_ns)
1057	return -EPERM;
1058
1059	if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
1060	err = -EPERM;
1061	break;
1062	case AUDIT_USER:
1063	case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1064	case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1065	if (!netlink_capable(skb, CAP_AUDIT_WRITE))
1066	err = -EPERM;
1067	break;
1068	default: /* bad msg */
1069	err = -EINVAL;
1070	}
1071
1072	return err;
1073	}
1074
1075	static void audit_log_common_recv_msg(struct audit_context *context,
1076	struct audit_buffer **ab, u16 msg_type)
1077	{
1078	uid_t uid = from_kuid(to: &init_user_ns, current_uid());
1079	pid_t pid = task_tgid_nr(current);
1080
1081	if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
1082	*ab = NULL;
1083	return;
1084	}
1085
1086	*ab = audit_log_start(ctx: context, GFP_KERNEL, type: msg_type);
1087	if (unlikely(!*ab))
1088	return;
1089	audit_log_format(ab: *ab, fmt: "pid=%d uid=%u ", pid, uid);
1090	audit_log_session_info(ab: *ab);
1091	audit_log_task_context(ab: *ab);
1092	}
1093
1094	static inline void audit_log_user_recv_msg(struct audit_buffer **ab,
1095	u16 msg_type)
1096	{
1097	audit_log_common_recv_msg(NULL, ab, msg_type);
1098	}
1099
1100	static int is_audit_feature_set(int i)
1101	{
1102	return af.features & AUDIT_FEATURE_TO_MASK(i);
1103	}
1104
1105
1106	static int audit_get_feature(struct sk_buff *skb)
1107	{
1108	u32 seq;
1109
1110	seq = nlmsg_hdr(skb)->nlmsg_seq;
1111
1112	audit_send_reply(request_skb: skb, seq, AUDIT_GET_FEATURE, done: 0, multi: 0, payload: &af, size: sizeof(af));
1113
1114	return 0;
1115	}
1116
1117	static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
1118	u32 old_lock, u32 new_lock, int res)
1119	{
1120	struct audit_buffer *ab;
1121
1122	if (audit_enabled == AUDIT_OFF)
1123	return;
1124
1125	ab = audit_log_start(ctx: audit_context(), GFP_KERNEL, AUDIT_FEATURE_CHANGE);
1126	if (!ab)
1127	return;
1128	audit_log_task_info(ab);
1129	audit_log_format(ab, fmt: " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
1130	audit_feature_names[which], !!old_feature, !!new_feature,
1131	!!old_lock, !!new_lock, res);
1132	audit_log_end(ab);
1133	}
1134
1135	static int audit_set_feature(struct audit_features *uaf)
1136	{
1137	int i;
1138
1139	BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
1140
1141	/* if there is ever a version 2 we should handle that here */
1142
1143	for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1144	u32 feature = AUDIT_FEATURE_TO_MASK(i);
1145	u32 old_feature, new_feature, old_lock, new_lock;
1146
1147	/* if we are not changing this feature, move along */
1148	if (!(feature & uaf->mask))
1149	continue;
1150
1151	old_feature = af.features & feature;
1152	new_feature = uaf->features & feature;
1153	new_lock = (uaf->lock | af.lock) & feature;
1154	old_lock = af.lock & feature;
1155
1156	/* are we changing a locked feature? */
1157	if (old_lock && (new_feature != old_feature)) {
1158	audit_log_feature_change(which: i, old_feature, new_feature,
1159	old_lock, new_lock, res: 0);
1160	return -EPERM;
1161	}
1162	}
1163	/* nothing invalid, do the changes */
1164	for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1165	u32 feature = AUDIT_FEATURE_TO_MASK(i);
1166	u32 old_feature, new_feature, old_lock, new_lock;
1167
1168	/* if we are not changing this feature, move along */
1169	if (!(feature & uaf->mask))
1170	continue;
1171
1172	old_feature = af.features & feature;
1173	new_feature = uaf->features & feature;
1174	old_lock = af.lock & feature;
1175	new_lock = (uaf->lock | af.lock) & feature;
1176
1177	if (new_feature != old_feature)
1178	audit_log_feature_change(which: i, old_feature, new_feature,
1179	old_lock, new_lock, res: 1);
1180
1181	if (new_feature)
1182	af.features |= feature;
1183	else
1184	af.features &= ~feature;
1185	af.lock |= new_lock;
1186	}
1187
1188	return 0;
1189	}
1190
1191	static int audit_replace(struct pid *pid)
1192	{
1193	pid_t pvnr;
1194	struct sk_buff *skb;
1195
1196	pvnr = pid_vnr(pid);
1197	skb = audit_make_reply(seq: 0, AUDIT_REPLACE, done: 0, multi: 0, payload: &pvnr, size: sizeof(pvnr));
1198	if (!skb)
1199	return -ENOMEM;
1200	return auditd_send_unicast_skb(skb);
1201	}
1202
1203	static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
1204	{
1205	u32 seq;
1206	void *data;
1207	int data_len;
1208	int err;
1209	struct audit_buffer *ab;
1210	u16 msg_type = nlh->nlmsg_type;
1211	struct audit_sig_info *sig_data;
1212	char *ctx = NULL;
1213	u32 len;
1214
1215	err = audit_netlink_ok(skb, msg_type);
1216	if (err)
1217	return err;
1218
1219	seq = nlh->nlmsg_seq;
1220	data = nlmsg_data(nlh);
1221	data_len = nlmsg_len(nlh);
1222
1223	switch (msg_type) {
1224	case AUDIT_GET: {
1225	struct audit_status s;
1226	memset(&s, 0, sizeof(s));
1227	s.enabled = audit_enabled;
1228	s.failure = audit_failure;
1229	/* NOTE: use pid_vnr() so the PID is relative to the current
1230	* namespace */
1231	s.pid = auditd_pid_vnr();
1232	s.rate_limit = audit_rate_limit;
1233	s.backlog_limit = audit_backlog_limit;
1234	s.lost = atomic_read(v: &audit_lost);
1235	s.backlog = skb_queue_len(list_: &audit_queue);
1236	s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL;
1237	s.backlog_wait_time = audit_backlog_wait_time;
1238	s.backlog_wait_time_actual = atomic_read(v: &audit_backlog_wait_time_actual);
1239	audit_send_reply(request_skb: skb, seq, AUDIT_GET, done: 0, multi: 0, payload: &s, size: sizeof(s));
1240	break;
1241	}
1242	case AUDIT_SET: {
1243	struct audit_status s;
1244	memset(&s, 0, sizeof(s));
1245	/* guard against past and future API changes */
1246	memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
1247	if (s.mask & AUDIT_STATUS_ENABLED) {
1248	err = audit_set_enabled(state: s.enabled);
1249	if (err < 0)
1250	return err;
1251	}
1252	if (s.mask & AUDIT_STATUS_FAILURE) {
1253	err = audit_set_failure(state: s.failure);
1254	if (err < 0)
1255	return err;
1256	}
1257	if (s.mask & AUDIT_STATUS_PID) {
1258	/* NOTE: we are using the vnr PID functions below
1259	* because the s.pid value is relative to the
1260	* namespace of the caller; at present this
1261	* doesn't matter much since you can really only
1262	* run auditd from the initial pid namespace, but
1263	* something to keep in mind if this changes */
1264	pid_t new_pid = s.pid;
1265	pid_t auditd_pid;
1266	struct pid *req_pid = task_tgid(current);
1267
1268	/* Sanity check - PID values must match. Setting
1269	* pid to 0 is how auditd ends auditing. */
1270	if (new_pid && (new_pid != pid_vnr(pid: req_pid)))
1271	return -EINVAL;
1272
1273	/* test the auditd connection */
1274	audit_replace(pid: req_pid);
1275
1276	auditd_pid = auditd_pid_vnr();
1277	if (auditd_pid) {
1278	/* replacing a healthy auditd is not allowed */
1279	if (new_pid) {
1280	audit_log_config_change(function_name: "audit_pid",
1281	new: new_pid, old: auditd_pid, allow_changes: 0);
1282	return -EEXIST;
1283	}
1284	/* only current auditd can unregister itself */
1285	if (pid_vnr(pid: req_pid) != auditd_pid) {
1286	audit_log_config_change(function_name: "audit_pid",
1287	new: new_pid, old: auditd_pid, allow_changes: 0);
1288	return -EACCES;
1289	}
1290	}
1291
1292	if (new_pid) {
1293	/* register a new auditd connection */
1294	err = auditd_set(pid: req_pid,
1295	NETLINK_CB(skb).portid,
1296	net: sock_net(NETLINK_CB(skb).sk));
1297	if (audit_enabled != AUDIT_OFF)
1298	audit_log_config_change(function_name: "audit_pid",
1299	new: new_pid,
1300	old: auditd_pid,
1301	allow_changes: err ? 0 : 1);
1302	if (err)
1303	return err;
1304
1305	/* try to process any backlog */
1306	wake_up_interruptible(&kauditd_wait);
1307	} else {
1308	if (audit_enabled != AUDIT_OFF)
1309	audit_log_config_change(function_name: "audit_pid",
1310	new: new_pid,
1311	old: auditd_pid, allow_changes: 1);
1312
1313	/* unregister the auditd connection */
1314	auditd_reset(NULL);
1315	}
1316	}
1317	if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
1318	err = audit_set_rate_limit(limit: s.rate_limit);
1319	if (err < 0)
1320	return err;
1321	}
1322	if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
1323	err = audit_set_backlog_limit(limit: s.backlog_limit);
1324	if (err < 0)
1325	return err;
1326	}
1327	if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
1328	if (sizeof(s) > (size_t)nlh->nlmsg_len)
1329	return -EINVAL;
1330	if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
1331	return -EINVAL;
1332	err = audit_set_backlog_wait_time(timeout: s.backlog_wait_time);
1333	if (err < 0)
1334	return err;
1335	}
1336	if (s.mask == AUDIT_STATUS_LOST) {
1337	u32 lost = atomic_xchg(v: &audit_lost, new: 0);
1338
1339	audit_log_config_change(function_name: "lost", new: 0, old: lost, allow_changes: 1);
1340	return lost;
1341	}
1342	if (s.mask == AUDIT_STATUS_BACKLOG_WAIT_TIME_ACTUAL) {
1343	u32 actual = atomic_xchg(v: &audit_backlog_wait_time_actual, new: 0);
1344
1345	audit_log_config_change(function_name: "backlog_wait_time_actual", new: 0, old: actual, allow_changes: 1);
1346	return actual;
1347	}
1348	break;
1349	}
1350	case AUDIT_GET_FEATURE:
1351	err = audit_get_feature(skb);
1352	if (err)
1353	return err;
1354	break;
1355	case AUDIT_SET_FEATURE:
1356	if (data_len < sizeof(struct audit_features))
1357	return -EINVAL;
1358	err = audit_set_feature(uaf: data);
1359	if (err)
1360	return err;
1361	break;
1362	case AUDIT_USER:
1363	case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1364	case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1365	if (!audit_enabled && msg_type != AUDIT_USER_AVC)
1366	return 0;
1367	/* exit early if there isn't at least one character to print */
1368	if (data_len < 2)
1369	return -EINVAL;
1370
1371	err = audit_filter(msgtype: msg_type, AUDIT_FILTER_USER);
1372	if (err == 1) { /* match or error */
1373	char *str = data;
1374
1375	err = 0;
1376	if (msg_type == AUDIT_USER_TTY) {
1377	err = tty_audit_push();
1378	if (err)
1379	break;
1380	}
1381	audit_log_user_recv_msg(ab: &ab, msg_type);
1382	if (msg_type != AUDIT_USER_TTY) {
1383	/* ensure NULL termination */
1384	str[data_len - 1] = '\0';
1385	audit_log_format(ab, fmt: " msg='%.*s'",
1386	AUDIT_MESSAGE_TEXT_MAX,
1387	str);
1388	} else {
1389	audit_log_format(ab, fmt: " data=");
1390	if (str[data_len - 1] == '\0')
1391	data_len--;
1392	audit_log_n_untrustedstring(ab, string: str, n: data_len);
1393	}
1394	audit_log_end(ab);
1395	}
1396	break;
1397	case AUDIT_ADD_RULE:
1398	case AUDIT_DEL_RULE:
1399	if (data_len < sizeof(struct audit_rule_data))
1400	return -EINVAL;
1401	if (audit_enabled == AUDIT_LOCKED) {
1402	audit_log_common_recv_msg(context: audit_context(), ab: &ab,
1403	AUDIT_CONFIG_CHANGE);
1404	audit_log_format(ab, fmt: " op=%s audit_enabled=%d res=0",
1405	msg_type == AUDIT_ADD_RULE ?
1406	"add_rule" : "remove_rule",
1407	audit_enabled);
1408	audit_log_end(ab);
1409	return -EPERM;
1410	}
1411	err = audit_rule_change(type: msg_type, seq, data, datasz: data_len);
1412	break;
1413	case AUDIT_LIST_RULES:
1414	err = audit_list_rules_send(request_skb: skb, seq);
1415	break;
1416	case AUDIT_TRIM:
1417	audit_trim_trees();
1418	audit_log_common_recv_msg(context: audit_context(), ab: &ab,
1419	AUDIT_CONFIG_CHANGE);
1420	audit_log_format(ab, fmt: " op=trim res=1");
1421	audit_log_end(ab);
1422	break;
1423	case AUDIT_MAKE_EQUIV: {
1424	void *bufp = data;
1425	u32 sizes[2];
1426	size_t msglen = data_len;
1427	char *old, *new;
1428
1429	err = -EINVAL;
1430	if (msglen < 2 * sizeof(u32))
1431	break;
1432	memcpy(sizes, bufp, 2 * sizeof(u32));
1433	bufp += 2 * sizeof(u32);
1434	msglen -= 2 * sizeof(u32);
1435	old = audit_unpack_string(bufp: &bufp, remain: &msglen, len: sizes[0]);
1436	if (IS_ERR(ptr: old)) {
1437	err = PTR_ERR(ptr: old);
1438	break;
1439	}
1440	new = audit_unpack_string(bufp: &bufp, remain: &msglen, len: sizes[1]);
1441	if (IS_ERR(ptr: new)) {
1442	err = PTR_ERR(ptr: new);
1443	kfree(objp: old);
1444	break;
1445	}
1446	/* OK, here comes... */
1447	err = audit_tag_tree(old, new);
1448
1449	audit_log_common_recv_msg(context: audit_context(), ab: &ab,
1450	AUDIT_CONFIG_CHANGE);
1451	audit_log_format(ab, fmt: " op=make_equiv old=");
1452	audit_log_untrustedstring(ab, string: old);
1453	audit_log_format(ab, fmt: " new=");
1454	audit_log_untrustedstring(ab, string: new);
1455	audit_log_format(ab, fmt: " res=%d", !err);
1456	audit_log_end(ab);
1457	kfree(objp: old);
1458	kfree(objp: new);
1459	break;
1460	}
1461	case AUDIT_SIGNAL_INFO:
1462	len = 0;
1463	if (audit_sig_sid) {
1464	err = security_secid_to_secctx(secid: audit_sig_sid, secdata: &ctx, seclen: &len);
1465	if (err)
1466	return err;
1467	}
1468	sig_data = kmalloc(struct_size(sig_data, ctx, len), GFP_KERNEL);
1469	if (!sig_data) {
1470	if (audit_sig_sid)
1471	security_release_secctx(secdata: ctx, seclen: len);
1472	return -ENOMEM;
1473	}
1474	sig_data->uid = from_kuid(to: &init_user_ns, uid: audit_sig_uid);
1475	sig_data->pid = audit_sig_pid;
1476	if (audit_sig_sid) {
1477	memcpy(sig_data->ctx, ctx, len);
1478	security_release_secctx(secdata: ctx, seclen: len);
1479	}
1480	audit_send_reply(request_skb: skb, seq, AUDIT_SIGNAL_INFO, done: 0, multi: 0,
1481	payload: sig_data, struct_size(sig_data, ctx, len));
1482	kfree(objp: sig_data);
1483	break;
1484	case AUDIT_TTY_GET: {
1485	struct audit_tty_status s;
1486	unsigned int t;
1487
1488	t = READ_ONCE(current->signal->audit_tty);
1489	s.enabled = t & AUDIT_TTY_ENABLE;
1490	s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1491
1492	audit_send_reply(request_skb: skb, seq, AUDIT_TTY_GET, done: 0, multi: 0, payload: &s, size: sizeof(s));
1493	break;
1494	}
1495	case AUDIT_TTY_SET: {
1496	struct audit_tty_status s, old;
1497	struct audit_buffer *ab;
1498	unsigned int t;
1499
1500	memset(&s, 0, sizeof(s));
1501	/* guard against past and future API changes */
1502	memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
1503	/* check if new data is valid */
1504	if ((s.enabled != 0 && s.enabled != 1) ||
1505	(s.log_passwd != 0 && s.log_passwd != 1))
1506	err = -EINVAL;
1507
1508	if (err)
1509	t = READ_ONCE(current->signal->audit_tty);
1510	else {
1511	t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD);
1512	t = xchg(&current->signal->audit_tty, t);
1513	}
1514	old.enabled = t & AUDIT_TTY_ENABLE;
1515	old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1516
1517	audit_log_common_recv_msg(context: audit_context(), ab: &ab,
1518	AUDIT_CONFIG_CHANGE);
1519	audit_log_format(ab, fmt: " op=tty_set old-enabled=%d new-enabled=%d"
1520	" old-log_passwd=%d new-log_passwd=%d res=%d",
1521	old.enabled, s.enabled, old.log_passwd,
1522	s.log_passwd, !err);
1523	audit_log_end(ab);
1524	break;
1525	}
1526	default:
1527	err = -EINVAL;
1528	break;
1529	}
1530
1531	return err < 0 ? err : 0;
1532	}
1533
1534	/**
1535	* audit_receive - receive messages from a netlink control socket
1536	* @skb: the message buffer
1537	*
1538	* Parse the provided skb and deal with any messages that may be present,
1539	* malformed skbs are discarded.
1540	*/
1541	static void audit_receive(struct sk_buff *skb)
1542	{
1543	struct nlmsghdr *nlh;
1544	/*
1545	* len MUST be signed for nlmsg_next to be able to dec it below 0
1546	* if the nlmsg_len was not aligned
1547	*/
1548	int len;
1549	int err;
1550
1551	nlh = nlmsg_hdr(skb);
1552	len = skb->len;
1553
1554	audit_ctl_lock();
1555	while (nlmsg_ok(nlh, remaining: len)) {
1556	err = audit_receive_msg(skb, nlh);
1557	/* if err or if this message says it wants a response */
1558	if (err || (nlh->nlmsg_flags & NLM_F_ACK))
1559	netlink_ack(in_skb: skb, nlh, err, NULL);
1560
1561	nlh = nlmsg_next(nlh, remaining: &len);
1562	}
1563	audit_ctl_unlock();
1564
1565	/* can't block with the ctrl lock, so penalize the sender now */
1566	if (audit_backlog_limit &&
1567	(skb_queue_len(list_: &audit_queue) > audit_backlog_limit)) {
1568	DECLARE_WAITQUEUE(wait, current);
1569
1570	/* wake kauditd to try and flush the queue */
1571	wake_up_interruptible(&kauditd_wait);
1572
1573	add_wait_queue_exclusive(wq_head: &audit_backlog_wait, wq_entry: &wait);
1574	set_current_state(TASK_UNINTERRUPTIBLE);
1575	schedule_timeout(timeout: audit_backlog_wait_time);
1576	remove_wait_queue(wq_head: &audit_backlog_wait, wq_entry: &wait);
1577	}
1578	}
1579
1580	/* Log information about who is connecting to the audit multicast socket */
1581	static void audit_log_multicast(int group, const char *op, int err)
1582	{
1583	const struct cred *cred;
1584	struct tty_struct *tty;
1585	char comm[sizeof(current->comm)];
1586	struct audit_buffer *ab;
1587
1588	if (!audit_enabled)
1589	return;
1590
1591	ab = audit_log_start(ctx: audit_context(), GFP_KERNEL, AUDIT_EVENT_LISTENER);
1592	if (!ab)
1593	return;
1594
1595	cred = current_cred();
1596	tty = audit_get_tty();
1597	audit_log_format(ab, fmt: "pid=%u uid=%u auid=%u tty=%s ses=%u",
1598	task_pid_nr(current),
1599	from_kuid(to: &init_user_ns, uid: cred->uid),
1600	from_kuid(to: &init_user_ns, uid: audit_get_loginuid(current)),
1601	tty ? tty_name(tty) : "(none)",
1602	audit_get_sessionid(current));
1603	audit_put_tty(tty);
1604	audit_log_task_context(ab); /* subj= */
1605	audit_log_format(ab, fmt: " comm=");
1606	audit_log_untrustedstring(ab, get_task_comm(comm, current));
1607	audit_log_d_path_exe(ab, current->mm); /* exe= */
1608	audit_log_format(ab, fmt: " nl-mcgrp=%d op=%s res=%d", group, op, !err);
1609	audit_log_end(ab);
1610	}
1611
1612	/* Run custom bind function on netlink socket group connect or bind requests. */
1613	static int audit_multicast_bind(struct net *net, int group)
1614	{
1615	int err = 0;
1616
1617	if (!capable(CAP_AUDIT_READ))
1618	err = -EPERM;
1619	audit_log_multicast(group, op: "connect", err);
1620	return err;
1621	}
1622
1623	static void audit_multicast_unbind(struct net *net, int group)
1624	{
1625	audit_log_multicast(group, op: "disconnect", err: 0);
1626	}
1627
1628	static int __net_init audit_net_init(struct net *net)
1629	{
1630	struct netlink_kernel_cfg cfg = {
1631	.input = audit_receive,
1632	.bind = audit_multicast_bind,
1633	.unbind = audit_multicast_unbind,
1634	.flags = NL_CFG_F_NONROOT_RECV,
1635	.groups = AUDIT_NLGRP_MAX,
1636	};
1637
1638	struct audit_net *aunet = net_generic(net, id: audit_net_id);
1639
1640	aunet->sk = netlink_kernel_create(net, NETLINK_AUDIT, cfg: &cfg);
1641	if (aunet->sk == NULL) {
1642	audit_panic(message: "cannot initialize netlink socket in namespace");
1643	return -ENOMEM;
1644	}
1645	/* limit the timeout in case auditd is blocked/stopped */
1646	aunet->sk->sk_sndtimeo = HZ / 10;
1647
1648	return 0;
1649	}
1650
1651	static void __net_exit audit_net_exit(struct net *net)
1652	{
1653	struct audit_net *aunet = net_generic(net, id: audit_net_id);
1654
1655	/* NOTE: you would think that we would want to check the auditd
1656	* connection and potentially reset it here if it lives in this
1657	* namespace, but since the auditd connection tracking struct holds a
1658	* reference to this namespace (see auditd_set()) we are only ever
1659	* going to get here after that connection has been released */
1660
1661	netlink_kernel_release(sk: aunet->sk);
1662	}
1663
1664	static struct pernet_operations audit_net_ops __net_initdata = {
1665	.init = audit_net_init,
1666	.exit = audit_net_exit,
1667	.id = &audit_net_id,
1668	.size = sizeof(struct audit_net),
1669	};
1670
1671	/* Initialize audit support at boot time. */
1672	static int __init audit_init(void)
1673	{
1674	int i;
1675
1676	if (audit_initialized == AUDIT_DISABLED)
1677	return 0;
1678
1679	audit_buffer_cache = kmem_cache_create(name: "audit_buffer",
1680	size: sizeof(struct audit_buffer),
1681	align: 0, SLAB_PANIC, NULL);
1682
1683	skb_queue_head_init(list: &audit_queue);
1684	skb_queue_head_init(list: &audit_retry_queue);
1685	skb_queue_head_init(list: &audit_hold_queue);
1686
1687	for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
1688	INIT_LIST_HEAD(list: &audit_inode_hash[i]);
1689
1690	mutex_init(&audit_cmd_mutex.lock);
1691	audit_cmd_mutex.owner = NULL;
1692
1693	pr_info("initializing netlink subsys (%s)\n",
1694	audit_default ? "enabled" : "disabled");
1695	register_pernet_subsys(&audit_net_ops);
1696
1697	audit_initialized = AUDIT_INITIALIZED;
1698
1699	kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
1700	if (IS_ERR(ptr: kauditd_task)) {
1701	int err = PTR_ERR(ptr: kauditd_task);
1702	panic(fmt: "audit: failed to start the kauditd thread (%d)\n", err);
1703	}
1704
1705	audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL,
1706	fmt: "state=initialized audit_enabled=%u res=1",
1707	audit_enabled);
1708
1709	return 0;
1710	}
1711	postcore_initcall(audit_init);
1712
1713	/*
1714	* Process kernel command-line parameter at boot time.
1715	* audit={0|off} or audit={1|on}.
1716	*/
1717	static int __init audit_enable(char *str)
1718	{
1719	if (!strcasecmp(s1: str, s2: "off") || !strcmp(str, "0"))
1720	audit_default = AUDIT_OFF;
1721	else if (!strcasecmp(s1: str, s2: "on") || !strcmp(str, "1"))
1722	audit_default = AUDIT_ON;
1723	else {
1724	pr_err("audit: invalid 'audit' parameter value (%s)\n", str);
1725	audit_default = AUDIT_ON;
1726	}
1727
1728	if (audit_default == AUDIT_OFF)
1729	audit_initialized = AUDIT_DISABLED;
1730	if (audit_set_enabled(state: audit_default))
1731	pr_err("audit: error setting audit state (%d)\n",
1732	audit_default);
1733
1734	pr_info("%s\n", audit_default ?
1735	"enabled (after initialization)" : "disabled (until reboot)");
1736
1737	return 1;
1738	}
1739	__setup("audit=", audit_enable);
1740
1741	/* Process kernel command-line parameter at boot time.
1742	* audit_backlog_limit=<n> */
1743	static int __init audit_backlog_limit_set(char *str)
1744	{
1745	u32 audit_backlog_limit_arg;
1746
1747	pr_info("audit_backlog_limit: ");
1748	if (kstrtouint(s: str, base: 0, res: &audit_backlog_limit_arg)) {
1749	pr_cont("using default of %u, unable to parse %s\n",
1750	audit_backlog_limit, str);
1751	return 1;
1752	}
1753
1754	audit_backlog_limit = audit_backlog_limit_arg;
1755	pr_cont("%d\n", audit_backlog_limit);
1756
1757	return 1;
1758	}
1759	__setup("audit_backlog_limit=", audit_backlog_limit_set);
1760
1761	static void audit_buffer_free(struct audit_buffer *ab)
1762	{
1763	if (!ab)
1764	return;
1765
1766	kfree_skb(skb: ab->skb);
1767	kmem_cache_free(s: audit_buffer_cache, objp: ab);
1768	}
1769
1770	static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx,
1771	gfp_t gfp_mask, int type)
1772	{
1773	struct audit_buffer *ab;
1774
1775	ab = kmem_cache_alloc(cachep: audit_buffer_cache, flags: gfp_mask);
1776	if (!ab)
1777	return NULL;
1778
1779	ab->skb = nlmsg_new(AUDIT_BUFSIZ, flags: gfp_mask);
1780	if (!ab->skb)
1781	goto err;
1782	if (!nlmsg_put(skb: ab->skb, portid: 0, seq: 0, type, payload: 0, flags: 0))
1783	goto err;
1784
1785	ab->ctx = ctx;
1786	ab->gfp_mask = gfp_mask;
1787
1788	return ab;
1789
1790	err:
1791	audit_buffer_free(ab);
1792	return NULL;
1793	}
1794
1795	/**
1796	* audit_serial - compute a serial number for the audit record
1797	*
1798	* Compute a serial number for the audit record. Audit records are
1799	* written to user-space as soon as they are generated, so a complete
1800	* audit record may be written in several pieces. The timestamp of the
1801	* record and this serial number are used by the user-space tools to
1802	* determine which pieces belong to the same audit record. The
1803	* (timestamp,serial) tuple is unique for each syscall and is live from
1804	* syscall entry to syscall exit.
1805	*
1806	* NOTE: Another possibility is to store the formatted records off the
1807	* audit context (for those records that have a context), and emit them
1808	* all at syscall exit. However, this could delay the reporting of
1809	* significant errors until syscall exit (or never, if the system
1810	* halts).
1811	*/
1812	unsigned int audit_serial(void)
1813	{
1814	static atomic_t serial = ATOMIC_INIT(0);
1815
1816	return atomic_inc_return(v: &serial);
1817	}
1818
1819	static inline void audit_get_stamp(struct audit_context *ctx,
1820	struct timespec64 *t, unsigned int *serial)
1821	{
1822	if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
1823	ktime_get_coarse_real_ts64(ts: t);
1824	*serial = audit_serial();
1825	}
1826	}
1827
1828	/**
1829	* audit_log_start - obtain an audit buffer
1830	* @ctx: audit_context (may be NULL)
1831	* @gfp_mask: type of allocation
1832	* @type: audit message type
1833	*
1834	* Returns audit_buffer pointer on success or NULL on error.
1835	*
1836	* Obtain an audit buffer. This routine does locking to obtain the
1837	* audit buffer, but then no locking is required for calls to
1838	* audit_log_*format. If the task (ctx) is a task that is currently in a
1839	* syscall, then the syscall is marked as auditable and an audit record
1840	* will be written at syscall exit. If there is no associated task, then
1841	* task context (ctx) should be NULL.
1842	*/
1843	struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1844	int type)
1845	{
1846	struct audit_buffer *ab;
1847	struct timespec64 t;
1848	unsigned int serial;
1849
1850	if (audit_initialized != AUDIT_INITIALIZED)
1851	return NULL;
1852
1853	if (unlikely(!audit_filter(type, AUDIT_FILTER_EXCLUDE)))
1854	return NULL;
1855
1856	/* NOTE: don't ever fail/sleep on these two conditions:
1857	* 1. auditd generated record - since we need auditd to drain the
1858	* queue; also, when we are checking for auditd, compare PIDs using
1859	* task_tgid_vnr() since auditd_pid is set in audit_receive_msg()
1860	* using a PID anchored in the caller's namespace
1861	* 2. generator holding the audit_cmd_mutex - we don't want to block
1862	* while holding the mutex, although we do penalize the sender
1863	* later in audit_receive() when it is safe to block
1864	*/
1865	if (!(auditd_test_task(current) || audit_ctl_owner_current())) {
1866	long stime = audit_backlog_wait_time;
1867
1868	while (audit_backlog_limit &&
1869	(skb_queue_len(list_: &audit_queue) > audit_backlog_limit)) {
1870	/* wake kauditd to try and flush the queue */
1871	wake_up_interruptible(&kauditd_wait);
1872
1873	/* sleep if we are allowed and we haven't exhausted our
1874	* backlog wait limit */
1875	if (gfpflags_allow_blocking(gfp_flags: gfp_mask) && (stime > 0)) {
1876	long rtime = stime;
1877
1878	DECLARE_WAITQUEUE(wait, current);
1879
1880	add_wait_queue_exclusive(wq_head: &audit_backlog_wait,
1881	wq_entry: &wait);
1882	set_current_state(TASK_UNINTERRUPTIBLE);
1883	stime = schedule_timeout(timeout: rtime);
1884	atomic_add(i: rtime - stime, v: &audit_backlog_wait_time_actual);
1885	remove_wait_queue(wq_head: &audit_backlog_wait, wq_entry: &wait);
1886	} else {
1887	if (audit_rate_check() && printk_ratelimit())
1888	pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
1889	skb_queue_len(&audit_queue),
1890	audit_backlog_limit);
1891	audit_log_lost(message: "backlog limit exceeded");
1892	return NULL;
1893	}
1894	}
1895	}
1896
1897	ab = audit_buffer_alloc(ctx, gfp_mask, type);
1898	if (!ab) {
1899	audit_log_lost(message: "out of memory in audit_log_start");
1900	return NULL;
1901	}
1902
1903	audit_get_stamp(ctx: ab->ctx, t: &t, serial: &serial);
1904	/* cancel dummy context to enable supporting records */
1905	if (ctx)
1906	ctx->dummy = 0;
1907	audit_log_format(ab, fmt: "audit(%llu.%03lu:%u): ",
1908	(unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
1909
1910	return ab;
1911	}
1912
1913	/**
1914	* audit_expand - expand skb in the audit buffer
1915	* @ab: audit_buffer
1916	* @extra: space to add at tail of the skb
1917	*
1918	* Returns 0 (no space) on failed expansion, or available space if
1919	* successful.
1920	*/
1921	static inline int audit_expand(struct audit_buffer *ab, int extra)
1922	{
1923	struct sk_buff *skb = ab->skb;
1924	int oldtail = skb_tailroom(skb);
1925	int ret = pskb_expand_head(skb, nhead: 0, ntail: extra, gfp_mask: ab->gfp_mask);
1926	int newtail = skb_tailroom(skb);
1927
1928	if (ret < 0) {
1929	audit_log_lost(message: "out of memory in audit_expand");
1930	return 0;
1931	}
1932
1933	skb->truesize += newtail - oldtail;
1934	return newtail;
1935	}
1936
1937	/*
1938	* Format an audit message into the audit buffer. If there isn't enough
1939	* room in the audit buffer, more room will be allocated and vsnprint
1940	* will be called a second time. Currently, we assume that a printk
1941	* can't format message larger than 1024 bytes, so we don't either.
1942	*/
1943	static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1944	va_list args)
1945	{
1946	int len, avail;
1947	struct sk_buff *skb;
1948	va_list args2;
1949
1950	if (!ab)
1951	return;
1952
1953	BUG_ON(!ab->skb);
1954	skb = ab->skb;
1955	avail = skb_tailroom(skb);
1956	if (avail == 0) {
1957	avail = audit_expand(ab, AUDIT_BUFSIZ);
1958	if (!avail)
1959	goto out;
1960	}
1961	va_copy(args2, args);
1962	len = vsnprintf(buf: skb_tail_pointer(skb), size: avail, fmt, args);
1963	if (len >= avail) {
1964	/* The printk buffer is 1024 bytes long, so if we get
1965	* here and AUDIT_BUFSIZ is at least 1024, then we can
1966	* log everything that printk could have logged. */
1967	avail = audit_expand(ab,
1968	max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1969	if (!avail)
1970	goto out_va_end;
1971	len = vsnprintf(buf: skb_tail_pointer(skb), size: avail, fmt, args: args2);
1972	}
1973	if (len > 0)
1974	skb_put(skb, len);
1975	out_va_end:
1976	va_end(args2);
1977	out:
1978	return;
1979	}
1980
1981	/**
1982	* audit_log_format - format a message into the audit buffer.
1983	* @ab: audit_buffer
1984	* @fmt: format string
1985	* @...: optional parameters matching @fmt string
1986	*
1987	* All the work is done in audit_log_vformat.
1988	*/
1989	void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1990	{
1991	va_list args;
1992
1993	if (!ab)
1994	return;
1995	va_start(args, fmt);
1996	audit_log_vformat(ab, fmt, args);
1997	va_end(args);
1998	}
1999
2000	/**
2001	* audit_log_n_hex - convert a buffer to hex and append it to the audit skb
2002	* @ab: the audit_buffer
2003	* @buf: buffer to convert to hex
2004	* @len: length of @buf to be converted
2005	*
2006	* No return value; failure to expand is silently ignored.
2007	*
2008	* This function will take the passed buf and convert it into a string of
2009	* ascii hex digits. The new string is placed onto the skb.
2010	*/
2011	void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
2012	size_t len)
2013	{
2014	int i, avail, new_len;
2015	unsigned char *ptr;
2016	struct sk_buff *skb;
2017
2018	if (!ab)
2019	return;
2020
2021	BUG_ON(!ab->skb);
2022	skb = ab->skb;
2023	avail = skb_tailroom(skb);
2024	new_len = len<<1;
2025	if (new_len >= avail) {
2026	/* Round the buffer request up to the next multiple */
2027	new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
2028	avail = audit_expand(ab, extra: new_len);
2029	if (!avail)
2030	return;
2031	}
2032
2033	ptr = skb_tail_pointer(skb);
2034	for (i = 0; i < len; i++)
2035	ptr = hex_byte_pack_upper(buf: ptr, byte: buf[i]);
2036	*ptr = 0;
2037	skb_put(skb, len: len << 1); /* new string is twice the old string */
2038	}
2039
2040	/*
2041	* Format a string of no more than slen characters into the audit buffer,
2042	* enclosed in quote marks.
2043	*/
2044	void audit_log_n_string(struct audit_buffer *ab, const char *string,
2045	size_t slen)
2046	{
2047	int avail, new_len;
2048	unsigned char *ptr;
2049	struct sk_buff *skb;
2050
2051	if (!ab)
2052	return;
2053
2054	BUG_ON(!ab->skb);
2055	skb = ab->skb;
2056	avail = skb_tailroom(skb);
2057	new_len = slen + 3; /* enclosing quotes + null terminator */
2058	if (new_len > avail) {
2059	avail = audit_expand(ab, extra: new_len);
2060	if (!avail)
2061	return;
2062	}
2063	ptr = skb_tail_pointer(skb);
2064	*ptr++ = '"';
2065	memcpy(ptr, string, slen);
2066	ptr += slen;
2067	*ptr++ = '"';
2068	*ptr = 0;
2069	skb_put(skb, len: slen + 2); /* don't include null terminator */
2070	}
2071
2072	/**
2073	* audit_string_contains_control - does a string need to be logged in hex
2074	* @string: string to be checked
2075	* @len: max length of the string to check
2076	*/
2077	bool audit_string_contains_control(const char *string, size_t len)
2078	{
2079	const unsigned char *p;
2080	for (p = string; p < (const unsigned char *)string + len; p++) {
2081	if (*p == '"' || *p < 0x21 || *p > 0x7e)
2082	return true;
2083	}
2084	return false;
2085	}
2086
2087	/**
2088	* audit_log_n_untrustedstring - log a string that may contain random characters
2089	* @ab: audit_buffer
2090	* @len: length of string (not including trailing null)
2091	* @string: string to be logged
2092	*
2093	* This code will escape a string that is passed to it if the string
2094	* contains a control character, unprintable character, double quote mark,
2095	* or a space. Unescaped strings will start and end with a double quote mark.
2096	* Strings that are escaped are printed in hex (2 digits per char).
2097	*
2098	* The caller specifies the number of characters in the string to log, which may
2099	* or may not be the entire string.
2100	*/
2101	void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
2102	size_t len)
2103	{
2104	if (audit_string_contains_control(string, len))
2105	audit_log_n_hex(ab, buf: string, len);
2106	else
2107	audit_log_n_string(ab, string, slen: len);
2108	}
2109
2110	/**
2111	* audit_log_untrustedstring - log a string that may contain random characters
2112	* @ab: audit_buffer
2113	* @string: string to be logged
2114	*
2115	* Same as audit_log_n_untrustedstring(), except that strlen is used to
2116	* determine string length.
2117	*/
2118	void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
2119	{
2120	audit_log_n_untrustedstring(ab, string, strlen(string));
2121	}
2122
2123	/* This is a helper-function to print the escaped d_path */
2124	void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
2125	const struct path *path)
2126	{
2127	char *p, *pathname;
2128
2129	if (prefix)
2130	audit_log_format(ab, fmt: "%s", prefix);
2131
2132	/* We will allow 11 spaces for ' (deleted)' to be appended */
2133	pathname = kmalloc(PATH_MAX+11, flags: ab->gfp_mask);
2134	if (!pathname) {
2135	audit_log_format(ab, fmt: "\"<no_memory>\"");
2136	return;
2137	}
2138	p = d_path(path, pathname, PATH_MAX+11);
2139	if (IS_ERR(ptr: p)) { /* Should never happen since we send PATH_MAX */
2140	/* FIXME: can we save some information here? */
2141	audit_log_format(ab, fmt: "\"<too_long>\"");
2142	} else
2143	audit_log_untrustedstring(ab, string: p);
2144	kfree(objp: pathname);
2145	}
2146
2147	void audit_log_session_info(struct audit_buffer *ab)
2148	{
2149	unsigned int sessionid = audit_get_sessionid(current);
2150	uid_t auid = from_kuid(to: &init_user_ns, uid: audit_get_loginuid(current));
2151
2152	audit_log_format(ab, fmt: "auid=%u ses=%u", auid, sessionid);
2153	}
2154
2155	void audit_log_key(struct audit_buffer *ab, char *key)
2156	{
2157	audit_log_format(ab, fmt: " key=");
2158	if (key)
2159	audit_log_untrustedstring(ab, string: key);
2160	else
2161	audit_log_format(ab, fmt: "(null)");
2162	}
2163
2164	int audit_log_task_context(struct audit_buffer *ab)
2165	{
2166	char *ctx = NULL;
2167	unsigned len;
2168	int error;
2169	u32 sid;
2170
2171	security_current_getsecid_subj(secid: &sid);
2172	if (!sid)
2173	return 0;
2174
2175	error = security_secid_to_secctx(secid: sid, secdata: &ctx, seclen: &len);
2176	if (error) {
2177	if (error != -EINVAL)
2178	goto error_path;
2179	return 0;
2180	}
2181
2182	audit_log_format(ab, fmt: " subj=%s", ctx);
2183	security_release_secctx(secdata: ctx, seclen: len);
2184	return 0;
2185
2186	error_path:
2187	audit_panic(message: "error in audit_log_task_context");
2188	return error;
2189	}
2190	EXPORT_SYMBOL(audit_log_task_context);
2191
2192	void audit_log_d_path_exe(struct audit_buffer *ab,
2193	struct mm_struct *mm)
2194	{
2195	struct file *exe_file;
2196
2197	if (!mm)
2198	goto out_null;
2199
2200	exe_file = get_mm_exe_file(mm);
2201	if (!exe_file)
2202	goto out_null;
2203
2204	audit_log_d_path(ab, prefix: " exe=", path: &exe_file->f_path);
2205	fput(exe_file);
2206	return;
2207	out_null:
2208	audit_log_format(ab, fmt: " exe=(null)");
2209	}
2210
2211	struct tty_struct *audit_get_tty(void)
2212	{
2213	struct tty_struct *tty = NULL;
2214	unsigned long flags;
2215
2216	spin_lock_irqsave(&current->sighand->siglock, flags);
2217	if (current->signal)
2218	tty = tty_kref_get(current->signal->tty);
2219	spin_unlock_irqrestore(lock: &current->sighand->siglock, flags);
2220	return tty;
2221	}
2222
2223	void audit_put_tty(struct tty_struct *tty)
2224	{
2225	tty_kref_put(tty);
2226	}
2227
2228	void audit_log_task_info(struct audit_buffer *ab)
2229	{
2230	const struct cred *cred;
2231	char comm[sizeof(current->comm)];
2232	struct tty_struct *tty;
2233
2234	if (!ab)
2235	return;
2236
2237	cred = current_cred();
2238	tty = audit_get_tty();
2239	audit_log_format(ab,
2240	fmt: " ppid=%d pid=%d auid=%u uid=%u gid=%u"
2241	" euid=%u suid=%u fsuid=%u"
2242	" egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
2243	task_ppid_nr(current),
2244	task_tgid_nr(current),
2245	from_kuid(to: &init_user_ns, uid: audit_get_loginuid(current)),
2246	from_kuid(to: &init_user_ns, uid: cred->uid),
2247	from_kgid(to: &init_user_ns, gid: cred->gid),
2248	from_kuid(to: &init_user_ns, uid: cred->euid),
2249	from_kuid(to: &init_user_ns, uid: cred->suid),
2250	from_kuid(to: &init_user_ns, uid: cred->fsuid),
2251	from_kgid(to: &init_user_ns, gid: cred->egid),
2252	from_kgid(to: &init_user_ns, gid: cred->sgid),
2253	from_kgid(to: &init_user_ns, gid: cred->fsgid),
2254	tty ? tty_name(tty) : "(none)",
2255	audit_get_sessionid(current));
2256	audit_put_tty(tty);
2257	audit_log_format(ab, fmt: " comm=");
2258	audit_log_untrustedstring(ab, get_task_comm(comm, current));
2259	audit_log_d_path_exe(ab, current->mm);
2260	audit_log_task_context(ab);
2261	}
2262	EXPORT_SYMBOL(audit_log_task_info);
2263
2264	/**
2265	* audit_log_path_denied - report a path restriction denial
2266	* @type: audit message type (AUDIT_ANOM_LINK, AUDIT_ANOM_CREAT, etc)
2267	* @operation: specific operation name
2268	*/
2269	void audit_log_path_denied(int type, const char *operation)
2270	{
2271	struct audit_buffer *ab;
2272
2273	if (!audit_enabled || audit_dummy_context())
2274	return;
2275
2276	/* Generate log with subject, operation, outcome. */
2277	ab = audit_log_start(ctx: audit_context(), GFP_KERNEL, type);
2278	if (!ab)
2279	return;
2280	audit_log_format(ab, fmt: "op=%s", operation);
2281	audit_log_task_info(ab);
2282	audit_log_format(ab, fmt: " res=0");
2283	audit_log_end(ab);
2284	}
2285
2286	/* global counter which is incremented every time something logs in */
2287	static atomic_t session_id = ATOMIC_INIT(0);
2288
2289	static int audit_set_loginuid_perm(kuid_t loginuid)
2290	{
2291	/* if we are unset, we don't need privs */
2292	if (!audit_loginuid_set(current))
2293	return 0;
2294	/* if AUDIT_FEATURE_LOGINUID_IMMUTABLE means never ever allow a change*/
2295	if (is_audit_feature_set(AUDIT_FEATURE_LOGINUID_IMMUTABLE))
2296	return -EPERM;
2297	/* it is set, you need permission */
2298	if (!capable(CAP_AUDIT_CONTROL))
2299	return -EPERM;
2300	/* reject if this is not an unset and we don't allow that */
2301	if (is_audit_feature_set(AUDIT_FEATURE_ONLY_UNSET_LOGINUID)
2302	&& uid_valid(uid: loginuid))
2303	return -EPERM;
2304	return 0;
2305	}
2306
2307	static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
2308	unsigned int oldsessionid,
2309	unsigned int sessionid, int rc)
2310	{
2311	struct audit_buffer *ab;
2312	uid_t uid, oldloginuid, loginuid;
2313	struct tty_struct *tty;
2314
2315	if (!audit_enabled)
2316	return;
2317
2318	ab = audit_log_start(ctx: audit_context(), GFP_KERNEL, AUDIT_LOGIN);
2319	if (!ab)
2320	return;
2321
2322	uid = from_kuid(to: &init_user_ns, task_uid(current));
2323	oldloginuid = from_kuid(to: &init_user_ns, uid: koldloginuid);
2324	loginuid = from_kuid(to: &init_user_ns, uid: kloginuid);
2325	tty = audit_get_tty();
2326
2327	audit_log_format(ab, fmt: "pid=%d uid=%u", task_tgid_nr(current), uid);
2328	audit_log_task_context(ab);
2329	audit_log_format(ab, fmt: " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",
2330	oldloginuid, loginuid, tty ? tty_name(tty) : "(none)",
2331	oldsessionid, sessionid, !rc);
2332	audit_put_tty(tty);
2333	audit_log_end(ab);
2334	}
2335
2336	/**
2337	* audit_set_loginuid - set current task's loginuid
2338	* @loginuid: loginuid value
2339	*
2340	* Returns 0.
2341	*
2342	* Called (set) from fs/proc/base.c::proc_loginuid_write().
2343	*/
2344	int audit_set_loginuid(kuid_t loginuid)
2345	{
2346	unsigned int oldsessionid, sessionid = AUDIT_SID_UNSET;
2347	kuid_t oldloginuid;
2348	int rc;
2349
2350	oldloginuid = audit_get_loginuid(current);
2351	oldsessionid = audit_get_sessionid(current);
2352
2353	rc = audit_set_loginuid_perm(loginuid);
2354	if (rc)
2355	goto out;
2356
2357	/* are we setting or clearing? */
2358	if (uid_valid(uid: loginuid)) {
2359	sessionid = (unsigned int)atomic_inc_return(v: &session_id);
2360	if (unlikely(sessionid == AUDIT_SID_UNSET))
2361	sessionid = (unsigned int)atomic_inc_return(v: &session_id);
2362	}
2363
2364	current->sessionid = sessionid;
2365	current->loginuid = loginuid;
2366	out:
2367	audit_log_set_loginuid(koldloginuid: oldloginuid, kloginuid: loginuid, oldsessionid, sessionid, rc);
2368	return rc;
2369	}
2370
2371	/**
2372	* audit_signal_info - record signal info for shutting down audit subsystem
2373	* @sig: signal value
2374	* @t: task being signaled
2375	*
2376	* If the audit subsystem is being terminated, record the task (pid)
2377	* and uid that is doing that.
2378	*/
2379	int audit_signal_info(int sig, struct task_struct *t)
2380	{
2381	kuid_t uid = current_uid(), auid;
2382
2383	if (auditd_test_task(task: t) &&
2384	(sig == SIGTERM || sig == SIGHUP ||
2385	sig == SIGUSR1 || sig == SIGUSR2)) {
2386	audit_sig_pid = task_tgid_nr(current);
2387	auid = audit_get_loginuid(current);
2388	if (uid_valid(uid: auid))
2389	audit_sig_uid = auid;
2390	else
2391	audit_sig_uid = uid;
2392	security_current_getsecid_subj(secid: &audit_sig_sid);
2393	}
2394
2395	return audit_signal_info_syscall(t);
2396	}
2397
2398	/**
2399	* audit_log_end - end one audit record
2400	* @ab: the audit_buffer
2401	*
2402	* We can not do a netlink send inside an irq context because it blocks (last
2403	* arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a
2404	* queue and a kthread is scheduled to remove them from the queue outside the
2405	* irq context. May be called in any context.
2406	*/
2407	void audit_log_end(struct audit_buffer *ab)
2408	{
2409	struct sk_buff *skb;
2410	struct nlmsghdr *nlh;
2411
2412	if (!ab)
2413	return;
2414
2415	if (audit_rate_check()) {
2416	skb = ab->skb;
2417	ab->skb = NULL;
2418
2419	/* setup the netlink header, see the comments in
2420	* kauditd_send_multicast_skb() for length quirks */
2421	nlh = nlmsg_hdr(skb);
2422	nlh->nlmsg_len = skb->len - NLMSG_HDRLEN;
2423
2424	/* queue the netlink packet and poke the kauditd thread */
2425	skb_queue_tail(list: &audit_queue, newsk: skb);
2426	wake_up_interruptible(&kauditd_wait);
2427	} else
2428	audit_log_lost(message: "rate limit exceeded");
2429
2430	audit_buffer_free(ab);
2431	}
2432
2433	/**
2434	* audit_log - Log an audit record
2435	* @ctx: audit context
2436	* @gfp_mask: type of allocation
2437	* @type: audit message type
2438	* @fmt: format string to use
2439	* @...: variable parameters matching the format string
2440	*
2441	* This is a convenience function that calls audit_log_start,
2442	* audit_log_vformat, and audit_log_end. It may be called
2443	* in any context.
2444	*/
2445	void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
2446	const char *fmt, ...)
2447	{
2448	struct audit_buffer *ab;
2449	va_list args;
2450
2451	ab = audit_log_start(ctx, gfp_mask, type);
2452	if (ab) {
2453	va_start(args, fmt);
2454	audit_log_vformat(ab, fmt, args);
2455	va_end(args);
2456	audit_log_end(ab);
2457	}
2458	}
2459
2460	EXPORT_SYMBOL(audit_log_start);
2461	EXPORT_SYMBOL(audit_log_end);
2462	EXPORT_SYMBOL(audit_log_format);
2463	EXPORT_SYMBOL(audit_log);
2464