projects/linux·blob v5.8 · refs

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