projects/linux·blob v5.4-rc1 · 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 */
105static struct auditd_connection {
106 struct pid *pid;
107 u32 portid;
108 struct net *net;
109 struct rcu_head rcu;
110} *auditd_conn = NULL;
111static DEFINE_SPINLOCK(auditd_conn_lock);
112
113/* If audit_rate_limit is non-zero, limit the rate of sending audit records
114 * to that number per second. This prevents DoS attacks, but results in
115 * audit records being dropped. */
116static u32 audit_rate_limit;
117
118/* Number of outstanding audit_buffers allowed.
119 * When set to zero, this means unlimited. */
120static u32 audit_backlog_limit = 64;
121#define AUDIT_BACKLOG_WAIT_TIME (60 * HZ)
122static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
123
124/* The identity of the user shutting down the audit system. */
125kuid_t audit_sig_uid = INVALID_UID;
126pid_t audit_sig_pid = -1;
127u32 audit_sig_sid = 0;
128
129/* Records can be lost in several ways:
130 0) [suppressed in audit_alloc]
131 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
132 2) out of memory in audit_log_move [alloc_skb]
133 3) suppressed due to audit_rate_limit
134 4) suppressed due to audit_backlog_limit
135*/
136static atomic_t audit_lost = ATOMIC_INIT(0);
137
138/* Hash for inode-based rules */
139struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
140
141static struct kmem_cache *audit_buffer_cache;
142
143/* queue msgs to send via kauditd_task */
144static struct sk_buff_head audit_queue;
145/* queue msgs due to temporary unicast send problems */
146static struct sk_buff_head audit_retry_queue;
147/* queue msgs waiting for new auditd connection */
148static struct sk_buff_head audit_hold_queue;
149
150/* queue servicing thread */
151static struct task_struct *kauditd_task;
152static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
153
154/* waitqueue for callers who are blocked on the audit backlog */
155static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
156
157static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION,
158 .mask = -1,
159 .features = 0,
160 .lock = 0,};
161
162static char *audit_feature_names[2] = {
163 "only_unset_loginuid",
164 "loginuid_immutable",
165};
166
167/**
168 * struct audit_ctl_mutex - serialize requests from userspace
169 * @lock: the mutex used for locking
170 * @owner: the task which owns the lock
171 *
172 * Description:
173 * This is the lock struct used to ensure we only process userspace requests
174 * in an orderly fashion. We can't simply use a mutex/lock here because we
175 * need to track lock ownership so we don't end up blocking the lock owner in
176 * audit_log_start() or similar.
177 */
178static struct audit_ctl_mutex {
179 struct mutex lock;
180 void *owner;
181} audit_cmd_mutex;
182
183/* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
184 * audit records. Since printk uses a 1024 byte buffer, this buffer
185 * should be at least that large. */
186#define AUDIT_BUFSIZ 1024
187
188/* The audit_buffer is used when formatting an audit record. The caller
189 * locks briefly to get the record off the freelist or to allocate the
190 * buffer, and locks briefly to send the buffer to the netlink layer or
191 * to place it on a transmit queue. Multiple audit_buffers can be in
192 * use simultaneously. */
193struct audit_buffer {
194 struct sk_buff *skb; /* formatted skb ready to send */
195 struct audit_context *ctx; /* NULL or associated context */
196 gfp_t gfp_mask;
197};
198
199struct audit_reply {
200 __u32 portid;
201 struct net *net;
202 struct sk_buff *skb;
203};
204
205/**
206 * auditd_test_task - Check to see if a given task is an audit daemon
207 * @task: the task to check
208 *
209 * Description:
210 * Return 1 if the task is a registered audit daemon, 0 otherwise.
211 */
212int auditd_test_task(struct task_struct *task)
213{
214 int rc;
215 struct auditd_connection *ac;
216
217 rcu_read_lock();
218 ac = rcu_dereference(auditd_conn);
219 rc = (ac && ac->pid == task_tgid(task) ? 1 : 0);
220 rcu_read_unlock();
221
222 return rc;
223}
224
225/**
226 * audit_ctl_lock - Take the audit control lock
227 */
228void audit_ctl_lock(void)
229{
230 mutex_lock(&audit_cmd_mutex.lock);
231 audit_cmd_mutex.owner = current;
232}
233
234/**
235 * audit_ctl_unlock - Drop the audit control lock
236 */
237void audit_ctl_unlock(void)
238{
239 audit_cmd_mutex.owner = NULL;
240 mutex_unlock(&audit_cmd_mutex.lock);
241}
242
243/**
244 * audit_ctl_owner_current - Test to see if the current task owns the lock
245 *
246 * Description:
247 * Return true if the current task owns the audit control lock, false if it
248 * doesn't own the lock.
249 */
250static bool audit_ctl_owner_current(void)
251{
252 return (current == audit_cmd_mutex.owner);
253}
254
255/**
256 * auditd_pid_vnr - Return the auditd PID relative to the namespace
257 *
258 * Description:
259 * Returns the PID in relation to the namespace, 0 on failure.
260 */
261static pid_t auditd_pid_vnr(void)
262{
263 pid_t pid;
264 const struct auditd_connection *ac;
265
266 rcu_read_lock();
267 ac = rcu_dereference(auditd_conn);
268 if (!ac || !ac->pid)
269 pid = 0;
270 else
271 pid = pid_vnr(ac->pid);
272 rcu_read_unlock();
273
274 return pid;
275}
276
277/**
278 * audit_get_sk - Return the audit socket for the given network namespace
279 * @net: the destination network namespace
280 *
281 * Description:
282 * Returns the sock pointer if valid, NULL otherwise. The caller must ensure
283 * that a reference is held for the network namespace while the sock is in use.
284 */
285static struct sock *audit_get_sk(const struct net *net)
286{
287 struct audit_net *aunet;
288
289 if (!net)
290 return NULL;
291
292 aunet = net_generic(net, audit_net_id);
293 return aunet->sk;
294}
295
296void audit_panic(const char *message)
297{
298 switch (audit_failure) {
299 case AUDIT_FAIL_SILENT:
300 break;
301 case AUDIT_FAIL_PRINTK:
302 if (printk_ratelimit())
303 pr_err("%s\n", message);
304 break;
305 case AUDIT_FAIL_PANIC:
306 panic("audit: %s\n", message);
307 break;
308 }
309}
310
311static inline int audit_rate_check(void)
312{
313 static unsigned long last_check = 0;
314 static int messages = 0;
315 static DEFINE_SPINLOCK(lock);
316 unsigned long flags;
317 unsigned long now;
318 unsigned long elapsed;
319 int retval = 0;
320
321 if (!audit_rate_limit) return 1;
322
323 spin_lock_irqsave(&lock, flags);
324 if (++messages < audit_rate_limit) {
325 retval = 1;
326 } else {
327 now = jiffies;
328 elapsed = now - last_check;
329 if (elapsed > HZ) {
330 last_check = now;
331 messages = 0;
332 retval = 1;
333 }
334 }
335 spin_unlock_irqrestore(&lock, flags);
336
337 return retval;
338}
339
340/**
341 * audit_log_lost - conditionally log lost audit message event
342 * @message: the message stating reason for lost audit message
343 *
344 * Emit at least 1 message per second, even if audit_rate_check is
345 * throttling.
346 * Always increment the lost messages counter.
347*/
348void audit_log_lost(const char *message)
349{
350 static unsigned long last_msg = 0;
351 static DEFINE_SPINLOCK(lock);
352 unsigned long flags;
353 unsigned long now;
354 int print;
355
356 atomic_inc(&audit_lost);
357
358 print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
359
360 if (!print) {
361 spin_lock_irqsave(&lock, flags);
362 now = jiffies;
363 if (now - last_msg > HZ) {
364 print = 1;
365 last_msg = now;
366 }
367 spin_unlock_irqrestore(&lock, flags);
368 }
369
370 if (print) {
371 if (printk_ratelimit())
372 pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
373 atomic_read(&audit_lost),
374 audit_rate_limit,
375 audit_backlog_limit);
376 audit_panic(message);
377 }
378}
379
380static int audit_log_config_change(char *function_name, u32 new, u32 old,
381 int allow_changes)
382{
383 struct audit_buffer *ab;
384 int rc = 0;
385
386 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
387 if (unlikely(!ab))
388 return rc;
389 audit_log_format(ab, "op=set %s=%u old=%u ", function_name, new, old);
390 audit_log_session_info(ab);
391 rc = audit_log_task_context(ab);
392 if (rc)
393 allow_changes = 0; /* Something weird, deny request */
394 audit_log_format(ab, " res=%d", allow_changes);
395 audit_log_end(ab);
396 return rc;
397}
398
399static int audit_do_config_change(char *function_name, u32 *to_change, u32 new)
400{
401 int allow_changes, rc = 0;
402 u32 old = *to_change;
403
404 /* check if we are locked */
405 if (audit_enabled == AUDIT_LOCKED)
406 allow_changes = 0;
407 else
408 allow_changes = 1;
409
410 if (audit_enabled != AUDIT_OFF) {
411 rc = audit_log_config_change(function_name, new, old, allow_changes);
412 if (rc)
413 allow_changes = 0;
414 }
415
416 /* If we are allowed, make the change */
417 if (allow_changes == 1)
418 *to_change = new;
419 /* Not allowed, update reason */
420 else if (rc == 0)
421 rc = -EPERM;
422 return rc;
423}
424
425static int audit_set_rate_limit(u32 limit)
426{
427 return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit);
428}
429
430static int audit_set_backlog_limit(u32 limit)
431{
432 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit);
433}
434
435static int audit_set_backlog_wait_time(u32 timeout)
436{
437 return audit_do_config_change("audit_backlog_wait_time",
438 &audit_backlog_wait_time, timeout);
439}
440
441static int audit_set_enabled(u32 state)
442{
443 int rc;
444 if (state > AUDIT_LOCKED)
445 return -EINVAL;
446
447 rc = audit_do_config_change("audit_enabled", &audit_enabled, state);
448 if (!rc)
449 audit_ever_enabled |= !!state;
450
451 return rc;
452}
453
454static int audit_set_failure(u32 state)
455{
456 if (state != AUDIT_FAIL_SILENT
457 && state != AUDIT_FAIL_PRINTK
458 && state != AUDIT_FAIL_PANIC)
459 return -EINVAL;
460
461 return audit_do_config_change("audit_failure", &audit_failure, state);
462}
463
464/**
465 * auditd_conn_free - RCU helper to release an auditd connection struct
466 * @rcu: RCU head
467 *
468 * Description:
469 * Drop any references inside the auditd connection tracking struct and free
470 * the memory.
471 */
472static void auditd_conn_free(struct rcu_head *rcu)
473{
474 struct auditd_connection *ac;
475
476 ac = container_of(rcu, struct auditd_connection, rcu);
477 put_pid(ac->pid);
478 put_net(ac->net);
479 kfree(ac);
480}
481
482/**
483 * auditd_set - Set/Reset the auditd connection state
484 * @pid: auditd PID
485 * @portid: auditd netlink portid
486 * @net: auditd network namespace pointer
487 *
488 * Description:
489 * This function will obtain and drop network namespace references as
490 * necessary. Returns zero on success, negative values on failure.
491 */
492static int auditd_set(struct pid *pid, u32 portid, struct net *net)
493{
494 unsigned long flags;
495 struct auditd_connection *ac_old, *ac_new;
496
497 if (!pid || !net)
498 return -EINVAL;
499
500 ac_new = kzalloc(sizeof(*ac_new), GFP_KERNEL);
501 if (!ac_new)
502 return -ENOMEM;
503 ac_new->pid = get_pid(pid);
504 ac_new->portid = portid;
505 ac_new->net = get_net(net);
506
507 spin_lock_irqsave(&auditd_conn_lock, flags);
508 ac_old = rcu_dereference_protected(auditd_conn,
509 lockdep_is_held(&auditd_conn_lock));
510 rcu_assign_pointer(auditd_conn, ac_new);
511 spin_unlock_irqrestore(&auditd_conn_lock, flags);
512
513 if (ac_old)
514 call_rcu(&ac_old->rcu, auditd_conn_free);
515
516 return 0;
517}
518
519/**
520 * kauditd_print_skb - Print the audit record to the ring buffer
521 * @skb: audit record
522 *
523 * Whatever the reason, this packet may not make it to the auditd connection
524 * so write it via printk so the information isn't completely lost.
525 */
526static void kauditd_printk_skb(struct sk_buff *skb)
527{
528 struct nlmsghdr *nlh = nlmsg_hdr(skb);
529 char *data = nlmsg_data(nlh);
530
531 if (nlh->nlmsg_type != AUDIT_EOE && printk_ratelimit())
532 pr_notice("type=%d %s\n", nlh->nlmsg_type, data);
533}
534
535/**
536 * kauditd_rehold_skb - Handle a audit record send failure in the hold queue
537 * @skb: audit record
538 *
539 * Description:
540 * This should only be used by the kauditd_thread when it fails to flush the
541 * hold queue.
542 */
543static void kauditd_rehold_skb(struct sk_buff *skb)
544{
545 /* put the record back in the queue at the same place */
546 skb_queue_head(&audit_hold_queue, skb);
547}
548
549/**
550 * kauditd_hold_skb - Queue an audit record, waiting for auditd
551 * @skb: audit record
552 *
553 * Description:
554 * Queue the audit record, waiting for an instance of auditd. When this
555 * function is called we haven't given up yet on sending the record, but things
556 * are not looking good. The first thing we want to do is try to write the
557 * record via printk and then see if we want to try and hold on to the record
558 * and queue it, if we have room. If we want to hold on to the record, but we
559 * don't have room, record a record lost message.
560 */
561static void kauditd_hold_skb(struct sk_buff *skb)
562{
563 /* at this point it is uncertain if we will ever send this to auditd so
564 * try to send the message via printk before we go any further */
565 kauditd_printk_skb(skb);
566
567 /* can we just silently drop the message? */
568 if (!audit_default) {
569 kfree_skb(skb);
570 return;
571 }
572
573 /* if we have room, queue the message */
574 if (!audit_backlog_limit ||
575 skb_queue_len(&audit_hold_queue) < audit_backlog_limit) {
576 skb_queue_tail(&audit_hold_queue, skb);
577 return;
578 }
579
580 /* we have no other options - drop the message */
581 audit_log_lost("kauditd hold queue overflow");
582 kfree_skb(skb);
583}
584
585/**
586 * kauditd_retry_skb - Queue an audit record, attempt to send again to auditd
587 * @skb: audit record
588 *
589 * Description:
590 * Not as serious as kauditd_hold_skb() as we still have a connected auditd,
591 * but for some reason we are having problems sending it audit records so
592 * queue the given record and attempt to resend.
593 */
594static void kauditd_retry_skb(struct sk_buff *skb)
595{
596 /* NOTE: because records should only live in the retry queue for a
597 * short period of time, before either being sent or moved to the hold
598 * queue, we don't currently enforce a limit on this queue */
599 skb_queue_tail(&audit_retry_queue, skb);
600}
601
602/**
603 * auditd_reset - Disconnect the auditd connection
604 * @ac: auditd connection state
605 *
606 * Description:
607 * Break the auditd/kauditd connection and move all the queued records into the
608 * hold queue in case auditd reconnects. It is important to note that the @ac
609 * pointer should never be dereferenced inside this function as it may be NULL
610 * or invalid, you can only compare the memory address! If @ac is NULL then
611 * the connection will always be reset.
612 */
613static void auditd_reset(const struct auditd_connection *ac)
614{
615 unsigned long flags;
616 struct sk_buff *skb;
617 struct auditd_connection *ac_old;
618
619 /* if it isn't already broken, break the connection */
620 spin_lock_irqsave(&auditd_conn_lock, flags);
621 ac_old = rcu_dereference_protected(auditd_conn,
622 lockdep_is_held(&auditd_conn_lock));
623 if (ac && ac != ac_old) {
624 /* someone already registered a new auditd connection */
625 spin_unlock_irqrestore(&auditd_conn_lock, flags);
626 return;
627 }
628 rcu_assign_pointer(auditd_conn, NULL);
629 spin_unlock_irqrestore(&auditd_conn_lock, flags);
630
631 if (ac_old)
632 call_rcu(&ac_old->rcu, auditd_conn_free);
633
634 /* flush the retry queue to the hold queue, but don't touch the main
635 * queue since we need to process that normally for multicast */
636 while ((skb = skb_dequeue(&audit_retry_queue)))
637 kauditd_hold_skb(skb);
638}
639
640/**
641 * auditd_send_unicast_skb - Send a record via unicast to auditd
642 * @skb: audit record
643 *
644 * Description:
645 * Send a skb to the audit daemon, returns positive/zero values on success and
646 * negative values on failure; in all cases the skb will be consumed by this
647 * function. If the send results in -ECONNREFUSED the connection with auditd
648 * will be reset. This function may sleep so callers should not hold any locks
649 * where this would cause a problem.
650 */
651static int auditd_send_unicast_skb(struct sk_buff *skb)
652{
653 int rc;
654 u32 portid;
655 struct net *net;
656 struct sock *sk;
657 struct auditd_connection *ac;
658
659 /* NOTE: we can't call netlink_unicast while in the RCU section so
660 * take a reference to the network namespace and grab local
661 * copies of the namespace, the sock, and the portid; the
662 * namespace and sock aren't going to go away while we hold a
663 * reference and if the portid does become invalid after the RCU
664 * section netlink_unicast() should safely return an error */
665
666 rcu_read_lock();
667 ac = rcu_dereference(auditd_conn);
668 if (!ac) {
669 rcu_read_unlock();
670 kfree_skb(skb);
671 rc = -ECONNREFUSED;
672 goto err;
673 }
674 net = get_net(ac->net);
675 sk = audit_get_sk(net);
676 portid = ac->portid;
677 rcu_read_unlock();
678
679 rc = netlink_unicast(sk, skb, portid, 0);
680 put_net(net);
681 if (rc < 0)
682 goto err;
683
684 return rc;
685
686err:
687 if (ac && rc == -ECONNREFUSED)
688 auditd_reset(ac);
689 return rc;
690}
691
692/**
693 * kauditd_send_queue - Helper for kauditd_thread to flush skb queues
694 * @sk: the sending sock
695 * @portid: the netlink destination
696 * @queue: the skb queue to process
697 * @retry_limit: limit on number of netlink unicast failures
698 * @skb_hook: per-skb hook for additional processing
699 * @err_hook: hook called if the skb fails the netlink unicast send
700 *
701 * Description:
702 * Run through the given queue and attempt to send the audit records to auditd,
703 * returns zero on success, negative values on failure. It is up to the caller
704 * to ensure that the @sk is valid for the duration of this function.
705 *
706 */
707static int kauditd_send_queue(struct sock *sk, u32 portid,
708 struct sk_buff_head *queue,
709 unsigned int retry_limit,
710 void (*skb_hook)(struct sk_buff *skb),
711 void (*err_hook)(struct sk_buff *skb))
712{
713 int rc = 0;
714 struct sk_buff *skb;
715 static unsigned int failed = 0;
716
717 /* NOTE: kauditd_thread takes care of all our locking, we just use
718 * the netlink info passed to us (e.g. sk and portid) */
719
720 while ((skb = skb_dequeue(queue))) {
721 /* call the skb_hook for each skb we touch */
722 if (skb_hook)
723 (*skb_hook)(skb);
724
725 /* can we send to anyone via unicast? */
726 if (!sk) {
727 if (err_hook)
728 (*err_hook)(skb);
729 continue;
730 }
731
732 /* grab an extra skb reference in case of error */
733 skb_get(skb);
734 rc = netlink_unicast(sk, skb, portid, 0);
735 if (rc < 0) {
736 /* fatal failure for our queue flush attempt? */
737 if (++failed >= retry_limit ||
738 rc == -ECONNREFUSED || rc == -EPERM) {
739 /* yes - error processing for the queue */
740 sk = NULL;
741 if (err_hook)
742 (*err_hook)(skb);
743 if (!skb_hook)
744 goto out;
745 /* keep processing with the skb_hook */
746 continue;
747 } else
748 /* no - requeue to preserve ordering */
749 skb_queue_head(queue, skb);
750 } else {
751 /* it worked - drop the extra reference and continue */
752 consume_skb(skb);
753 failed = 0;
754 }
755 }
756
757out:
758 return (rc >= 0 ? 0 : rc);
759}
760
761/*
762 * kauditd_send_multicast_skb - Send a record to any multicast listeners
763 * @skb: audit record
764 *
765 * Description:
766 * Write a multicast message to anyone listening in the initial network
767 * namespace. This function doesn't consume an skb as might be expected since
768 * it has to copy it anyways.
769 */
770static void kauditd_send_multicast_skb(struct sk_buff *skb)
771{
772 struct sk_buff *copy;
773 struct sock *sock = audit_get_sk(&init_net);
774 struct nlmsghdr *nlh;
775
776 /* NOTE: we are not taking an additional reference for init_net since
777 * we don't have to worry about it going away */
778
779 if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
780 return;
781
782 /*
783 * The seemingly wasteful skb_copy() rather than bumping the refcount
784 * using skb_get() is necessary because non-standard mods are made to
785 * the skb by the original kaudit unicast socket send routine. The
786 * existing auditd daemon assumes this breakage. Fixing this would
787 * require co-ordinating a change in the established protocol between
788 * the kaudit kernel subsystem and the auditd userspace code. There is
789 * no reason for new multicast clients to continue with this
790 * non-compliance.
791 */
792 copy = skb_copy(skb, GFP_KERNEL);
793 if (!copy)
794 return;
795 nlh = nlmsg_hdr(copy);
796 nlh->nlmsg_len = skb->len;
797
798 nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL);
799}
800
801/**
802 * kauditd_thread - Worker thread to send audit records to userspace
803 * @dummy: unused
804 */
805static int kauditd_thread(void *dummy)
806{
807 int rc;
808 u32 portid = 0;
809 struct net *net = NULL;
810 struct sock *sk = NULL;
811 struct auditd_connection *ac;
812
813#define UNICAST_RETRIES 5
814
815 set_freezable();
816 while (!kthread_should_stop()) {
817 /* NOTE: see the lock comments in auditd_send_unicast_skb() */
818 rcu_read_lock();
819 ac = rcu_dereference(auditd_conn);
820 if (!ac) {
821 rcu_read_unlock();
822 goto main_queue;
823 }
824 net = get_net(ac->net);
825 sk = audit_get_sk(net);
826 portid = ac->portid;
827 rcu_read_unlock();
828
829 /* attempt to flush the hold queue */
830 rc = kauditd_send_queue(sk, portid,
831 &audit_hold_queue, UNICAST_RETRIES,
832 NULL, kauditd_rehold_skb);
833 if (ac && rc < 0) {
834 sk = NULL;
835 auditd_reset(ac);
836 goto main_queue;
837 }
838
839 /* attempt to flush the retry queue */
840 rc = kauditd_send_queue(sk, portid,
841 &audit_retry_queue, UNICAST_RETRIES,
842 NULL, kauditd_hold_skb);
843 if (ac && rc < 0) {
844 sk = NULL;
845 auditd_reset(ac);
846 goto main_queue;
847 }
848
849main_queue:
850 /* process the main queue - do the multicast send and attempt
851 * unicast, dump failed record sends to the retry queue; if
852 * sk == NULL due to previous failures we will just do the
853 * multicast send and move the record to the hold queue */
854 rc = kauditd_send_queue(sk, portid, &audit_queue, 1,
855 kauditd_send_multicast_skb,
856 (sk ?
857 kauditd_retry_skb : kauditd_hold_skb));
858 if (ac && rc < 0)
859 auditd_reset(ac);
860 sk = NULL;
861
862 /* drop our netns reference, no auditd sends past this line */
863 if (net) {
864 put_net(net);
865 net = NULL;
866 }
867
868 /* we have processed all the queues so wake everyone */
869 wake_up(&audit_backlog_wait);
870
871 /* NOTE: we want to wake up if there is anything on the queue,
872 * regardless of if an auditd is connected, as we need to
873 * do the multicast send and rotate records from the
874 * main queue to the retry/hold queues */
875 wait_event_freezable(kauditd_wait,
876 (skb_queue_len(&audit_queue) ? 1 : 0));
877 }
878
879 return 0;
880}
881
882int audit_send_list(void *_dest)
883{
884 struct audit_netlink_list *dest = _dest;
885 struct sk_buff *skb;
886 struct sock *sk = audit_get_sk(dest->net);
887
888 /* wait for parent to finish and send an ACK */
889 audit_ctl_lock();
890 audit_ctl_unlock();
891
892 while ((skb = __skb_dequeue(&dest->q)) != NULL)
893 netlink_unicast(sk, skb, dest->portid, 0);
894
895 put_net(dest->net);
896 kfree(dest);
897
898 return 0;
899}
900
901struct sk_buff *audit_make_reply(int seq, int type, int done,
902 int multi, const void *payload, int size)
903{
904 struct sk_buff *skb;
905 struct nlmsghdr *nlh;
906 void *data;
907 int flags = multi ? NLM_F_MULTI : 0;
908 int t = done ? NLMSG_DONE : type;
909
910 skb = nlmsg_new(size, GFP_KERNEL);
911 if (!skb)
912 return NULL;
913
914 nlh = nlmsg_put(skb, 0, seq, t, size, flags);
915 if (!nlh)
916 goto out_kfree_skb;
917 data = nlmsg_data(nlh);
918 memcpy(data, payload, size);
919 return skb;
920
921out_kfree_skb:
922 kfree_skb(skb);
923 return NULL;
924}
925
926static int audit_send_reply_thread(void *arg)
927{
928 struct audit_reply *reply = (struct audit_reply *)arg;
929 struct sock *sk = audit_get_sk(reply->net);
930
931 audit_ctl_lock();
932 audit_ctl_unlock();
933
934 /* Ignore failure. It'll only happen if the sender goes away,
935 because our timeout is set to infinite. */
936 netlink_unicast(sk, reply->skb, reply->portid, 0);
937 put_net(reply->net);
938 kfree(reply);
939 return 0;
940}
941
942/**
943 * audit_send_reply - send an audit reply message via netlink
944 * @request_skb: skb of request we are replying to (used to target the reply)
945 * @seq: sequence number
946 * @type: audit message type
947 * @done: done (last) flag
948 * @multi: multi-part message flag
949 * @payload: payload data
950 * @size: payload size
951 *
952 * Allocates an skb, builds the netlink message, and sends it to the port id.
953 * No failure notifications.
954 */
955static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
956 int multi, const void *payload, int size)
957{
958 struct net *net = sock_net(NETLINK_CB(request_skb).sk);
959 struct sk_buff *skb;
960 struct task_struct *tsk;
961 struct audit_reply *reply = kmalloc(sizeof(struct audit_reply),
962 GFP_KERNEL);
963
964 if (!reply)
965 return;
966
967 skb = audit_make_reply(seq, type, done, multi, payload, size);
968 if (!skb)
969 goto out;
970
971 reply->net = get_net(net);
972 reply->portid = NETLINK_CB(request_skb).portid;
973 reply->skb = skb;
974
975 tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
976 if (!IS_ERR(tsk))
977 return;
978 kfree_skb(skb);
979out:
980 kfree(reply);
981}
982
983/*
984 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
985 * control messages.
986 */
987static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
988{
989 int err = 0;
990
991 /* Only support initial user namespace for now. */
992 /*
993 * We return ECONNREFUSED because it tricks userspace into thinking
994 * that audit was not configured into the kernel. Lots of users
995 * configure their PAM stack (because that's what the distro does)
996 * to reject login if unable to send messages to audit. If we return
997 * ECONNREFUSED the PAM stack thinks the kernel does not have audit
998 * configured in and will let login proceed. If we return EPERM
999 * userspace will reject all logins. This should be removed when we
1000 * support non init namespaces!!
1001 */
1002 if (current_user_ns() != &init_user_ns)
1003 return -ECONNREFUSED;
1004
1005 switch (msg_type) {
1006 case AUDIT_LIST:
1007 case AUDIT_ADD:
1008 case AUDIT_DEL:
1009 return -EOPNOTSUPP;
1010 case AUDIT_GET:
1011 case AUDIT_SET:
1012 case AUDIT_GET_FEATURE:
1013 case AUDIT_SET_FEATURE:
1014 case AUDIT_LIST_RULES:
1015 case AUDIT_ADD_RULE:
1016 case AUDIT_DEL_RULE:
1017 case AUDIT_SIGNAL_INFO:
1018 case AUDIT_TTY_GET:
1019 case AUDIT_TTY_SET:
1020 case AUDIT_TRIM:
1021 case AUDIT_MAKE_EQUIV:
1022 /* Only support auditd and auditctl in initial pid namespace
1023 * for now. */
1024 if (task_active_pid_ns(current) != &init_pid_ns)
1025 return -EPERM;
1026
1027 if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
1028 err = -EPERM;
1029 break;
1030 case AUDIT_USER:
1031 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1032 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1033 if (!netlink_capable(skb, CAP_AUDIT_WRITE))
1034 err = -EPERM;
1035 break;
1036 default: /* bad msg */
1037 err = -EINVAL;
1038 }
1039
1040 return err;
1041}
1042
1043static void audit_log_common_recv_msg(struct audit_context *context,
1044 struct audit_buffer **ab, u16 msg_type)
1045{
1046 uid_t uid = from_kuid(&init_user_ns, current_uid());
1047 pid_t pid = task_tgid_nr(current);
1048
1049 if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
1050 *ab = NULL;
1051 return;
1052 }
1053
1054 *ab = audit_log_start(context, GFP_KERNEL, msg_type);
1055 if (unlikely(!*ab))
1056 return;
1057 audit_log_format(*ab, "pid=%d uid=%u ", pid, uid);
1058 audit_log_session_info(*ab);
1059 audit_log_task_context(*ab);
1060}
1061
1062static inline void audit_log_user_recv_msg(struct audit_buffer **ab,
1063 u16 msg_type)
1064{
1065 audit_log_common_recv_msg(NULL, ab, msg_type);
1066}
1067
1068int is_audit_feature_set(int i)
1069{
1070 return af.features & AUDIT_FEATURE_TO_MASK(i);
1071}
1072
1073
1074static int audit_get_feature(struct sk_buff *skb)
1075{
1076 u32 seq;
1077
1078 seq = nlmsg_hdr(skb)->nlmsg_seq;
1079
1080 audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af));
1081
1082 return 0;
1083}
1084
1085static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
1086 u32 old_lock, u32 new_lock, int res)
1087{
1088 struct audit_buffer *ab;
1089
1090 if (audit_enabled == AUDIT_OFF)
1091 return;
1092
1093 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_FEATURE_CHANGE);
1094 if (!ab)
1095 return;
1096 audit_log_task_info(ab);
1097 audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
1098 audit_feature_names[which], !!old_feature, !!new_feature,
1099 !!old_lock, !!new_lock, res);
1100 audit_log_end(ab);
1101}
1102
1103static int audit_set_feature(struct sk_buff *skb)
1104{
1105 struct audit_features *uaf;
1106 int i;
1107
1108 BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
1109 uaf = nlmsg_data(nlmsg_hdr(skb));
1110
1111 /* if there is ever a version 2 we should handle that here */
1112
1113 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1114 u32 feature = AUDIT_FEATURE_TO_MASK(i);
1115 u32 old_feature, new_feature, old_lock, new_lock;
1116
1117 /* if we are not changing this feature, move along */
1118 if (!(feature & uaf->mask))
1119 continue;
1120
1121 old_feature = af.features & feature;
1122 new_feature = uaf->features & feature;
1123 new_lock = (uaf->lock | af.lock) & feature;
1124 old_lock = af.lock & feature;
1125
1126 /* are we changing a locked feature? */
1127 if (old_lock && (new_feature != old_feature)) {
1128 audit_log_feature_change(i, old_feature, new_feature,
1129 old_lock, new_lock, 0);
1130 return -EPERM;
1131 }
1132 }
1133 /* nothing invalid, do the changes */
1134 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1135 u32 feature = AUDIT_FEATURE_TO_MASK(i);
1136 u32 old_feature, new_feature, old_lock, new_lock;
1137
1138 /* if we are not changing this feature, move along */
1139 if (!(feature & uaf->mask))
1140 continue;
1141
1142 old_feature = af.features & feature;
1143 new_feature = uaf->features & feature;
1144 old_lock = af.lock & feature;
1145 new_lock = (uaf->lock | af.lock) & feature;
1146
1147 if (new_feature != old_feature)
1148 audit_log_feature_change(i, old_feature, new_feature,
1149 old_lock, new_lock, 1);
1150
1151 if (new_feature)
1152 af.features |= feature;
1153 else
1154 af.features &= ~feature;
1155 af.lock |= new_lock;
1156 }
1157
1158 return 0;
1159}
1160
1161static int audit_replace(struct pid *pid)
1162{
1163 pid_t pvnr;
1164 struct sk_buff *skb;
1165
1166 pvnr = pid_vnr(pid);
1167 skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pvnr, sizeof(pvnr));
1168 if (!skb)
1169 return -ENOMEM;
1170 return auditd_send_unicast_skb(skb);
1171}
1172
1173static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
1174{
1175 u32 seq;
1176 void *data;
1177 int err;
1178 struct audit_buffer *ab;
1179 u16 msg_type = nlh->nlmsg_type;
1180 struct audit_sig_info *sig_data;
1181 char *ctx = NULL;
1182 u32 len;
1183
1184 err = audit_netlink_ok(skb, msg_type);
1185 if (err)
1186 return err;
1187
1188 seq = nlh->nlmsg_seq;
1189 data = nlmsg_data(nlh);
1190
1191 switch (msg_type) {
1192 case AUDIT_GET: {
1193 struct audit_status s;
1194 memset(&s, 0, sizeof(s));
1195 s.enabled = audit_enabled;
1196 s.failure = audit_failure;
1197 /* NOTE: use pid_vnr() so the PID is relative to the current
1198 * namespace */
1199 s.pid = auditd_pid_vnr();
1200 s.rate_limit = audit_rate_limit;
1201 s.backlog_limit = audit_backlog_limit;
1202 s.lost = atomic_read(&audit_lost);
1203 s.backlog = skb_queue_len(&audit_queue);
1204 s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL;
1205 s.backlog_wait_time = audit_backlog_wait_time;
1206 audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
1207 break;
1208 }
1209 case AUDIT_SET: {
1210 struct audit_status s;
1211 memset(&s, 0, sizeof(s));
1212 /* guard against past and future API changes */
1213 memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
1214 if (s.mask & AUDIT_STATUS_ENABLED) {
1215 err = audit_set_enabled(s.enabled);
1216 if (err < 0)
1217 return err;
1218 }
1219 if (s.mask & AUDIT_STATUS_FAILURE) {
1220 err = audit_set_failure(s.failure);
1221 if (err < 0)
1222 return err;
1223 }
1224 if (s.mask & AUDIT_STATUS_PID) {
1225 /* NOTE: we are using the vnr PID functions below
1226 * because the s.pid value is relative to the
1227 * namespace of the caller; at present this
1228 * doesn't matter much since you can really only
1229 * run auditd from the initial pid namespace, but
1230 * something to keep in mind if this changes */
1231 pid_t new_pid = s.pid;
1232 pid_t auditd_pid;
1233 struct pid *req_pid = task_tgid(current);
1234
1235 /* Sanity check - PID values must match. Setting
1236 * pid to 0 is how auditd ends auditing. */
1237 if (new_pid && (new_pid != pid_vnr(req_pid)))
1238 return -EINVAL;
1239
1240 /* test the auditd connection */
1241 audit_replace(req_pid);
1242
1243 auditd_pid = auditd_pid_vnr();
1244 if (auditd_pid) {
1245 /* replacing a healthy auditd is not allowed */
1246 if (new_pid) {
1247 audit_log_config_change("audit_pid",
1248 new_pid, auditd_pid, 0);
1249 return -EEXIST;
1250 }
1251 /* only current auditd can unregister itself */
1252 if (pid_vnr(req_pid) != auditd_pid) {
1253 audit_log_config_change("audit_pid",
1254 new_pid, auditd_pid, 0);
1255 return -EACCES;
1256 }
1257 }
1258
1259 if (new_pid) {
1260 /* register a new auditd connection */
1261 err = auditd_set(req_pid,
1262 NETLINK_CB(skb).portid,
1263 sock_net(NETLINK_CB(skb).sk));
1264 if (audit_enabled != AUDIT_OFF)
1265 audit_log_config_change("audit_pid",
1266 new_pid,
1267 auditd_pid,
1268 err ? 0 : 1);
1269 if (err)
1270 return err;
1271
1272 /* try to process any backlog */
1273 wake_up_interruptible(&kauditd_wait);
1274 } else {
1275 if (audit_enabled != AUDIT_OFF)
1276 audit_log_config_change("audit_pid",
1277 new_pid,
1278 auditd_pid, 1);
1279
1280 /* unregister the auditd connection */
1281 auditd_reset(NULL);
1282 }
1283 }
1284 if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
1285 err = audit_set_rate_limit(s.rate_limit);
1286 if (err < 0)
1287 return err;
1288 }
1289 if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
1290 err = audit_set_backlog_limit(s.backlog_limit);
1291 if (err < 0)
1292 return err;
1293 }
1294 if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
1295 if (sizeof(s) > (size_t)nlh->nlmsg_len)
1296 return -EINVAL;
1297 if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
1298 return -EINVAL;
1299 err = audit_set_backlog_wait_time(s.backlog_wait_time);
1300 if (err < 0)
1301 return err;
1302 }
1303 if (s.mask == AUDIT_STATUS_LOST) {
1304 u32 lost = atomic_xchg(&audit_lost, 0);
1305
1306 audit_log_config_change("lost", 0, lost, 1);
1307 return lost;
1308 }
1309 break;
1310 }
1311 case AUDIT_GET_FEATURE:
1312 err = audit_get_feature(skb);
1313 if (err)
1314 return err;
1315 break;
1316 case AUDIT_SET_FEATURE:
1317 err = audit_set_feature(skb);
1318 if (err)
1319 return err;
1320 break;
1321 case AUDIT_USER:
1322 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1323 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1324 if (!audit_enabled && msg_type != AUDIT_USER_AVC)
1325 return 0;
1326
1327 err = audit_filter(msg_type, AUDIT_FILTER_USER);
1328 if (err == 1) { /* match or error */
1329 err = 0;
1330 if (msg_type == AUDIT_USER_TTY) {
1331 err = tty_audit_push();
1332 if (err)
1333 break;
1334 }
1335 audit_log_user_recv_msg(&ab, msg_type);
1336 if (msg_type != AUDIT_USER_TTY)
1337 audit_log_format(ab, " msg='%.*s'",
1338 AUDIT_MESSAGE_TEXT_MAX,
1339 (char *)data);
1340 else {
1341 int size;
1342
1343 audit_log_format(ab, " data=");
1344 size = nlmsg_len(nlh);
1345 if (size > 0 &&
1346 ((unsigned char *)data)[size - 1] == '\0')
1347 size--;
1348 audit_log_n_untrustedstring(ab, data, size);
1349 }
1350 audit_log_end(ab);
1351 }
1352 break;
1353 case AUDIT_ADD_RULE:
1354 case AUDIT_DEL_RULE:
1355 if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
1356 return -EINVAL;
1357 if (audit_enabled == AUDIT_LOCKED) {
1358 audit_log_common_recv_msg(audit_context(), &ab,
1359 AUDIT_CONFIG_CHANGE);
1360 audit_log_format(ab, " op=%s audit_enabled=%d res=0",
1361 msg_type == AUDIT_ADD_RULE ?
1362 "add_rule" : "remove_rule",
1363 audit_enabled);
1364 audit_log_end(ab);
1365 return -EPERM;
1366 }
1367 err = audit_rule_change(msg_type, seq, data, nlmsg_len(nlh));
1368 break;
1369 case AUDIT_LIST_RULES:
1370 err = audit_list_rules_send(skb, seq);
1371 break;
1372 case AUDIT_TRIM:
1373 audit_trim_trees();
1374 audit_log_common_recv_msg(audit_context(), &ab,
1375 AUDIT_CONFIG_CHANGE);
1376 audit_log_format(ab, " op=trim res=1");
1377 audit_log_end(ab);
1378 break;
1379 case AUDIT_MAKE_EQUIV: {
1380 void *bufp = data;
1381 u32 sizes[2];
1382 size_t msglen = nlmsg_len(nlh);
1383 char *old, *new;
1384
1385 err = -EINVAL;
1386 if (msglen < 2 * sizeof(u32))
1387 break;
1388 memcpy(sizes, bufp, 2 * sizeof(u32));
1389 bufp += 2 * sizeof(u32);
1390 msglen -= 2 * sizeof(u32);
1391 old = audit_unpack_string(&bufp, &msglen, sizes[0]);
1392 if (IS_ERR(old)) {
1393 err = PTR_ERR(old);
1394 break;
1395 }
1396 new = audit_unpack_string(&bufp, &msglen, sizes[1]);
1397 if (IS_ERR(new)) {
1398 err = PTR_ERR(new);
1399 kfree(old);
1400 break;
1401 }
1402 /* OK, here comes... */
1403 err = audit_tag_tree(old, new);
1404
1405 audit_log_common_recv_msg(audit_context(), &ab,
1406 AUDIT_CONFIG_CHANGE);
1407 audit_log_format(ab, " op=make_equiv old=");
1408 audit_log_untrustedstring(ab, old);
1409 audit_log_format(ab, " new=");
1410 audit_log_untrustedstring(ab, new);
1411 audit_log_format(ab, " res=%d", !err);
1412 audit_log_end(ab);
1413 kfree(old);
1414 kfree(new);
1415 break;
1416 }
1417 case AUDIT_SIGNAL_INFO:
1418 len = 0;
1419 if (audit_sig_sid) {
1420 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
1421 if (err)
1422 return err;
1423 }
1424 sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
1425 if (!sig_data) {
1426 if (audit_sig_sid)
1427 security_release_secctx(ctx, len);
1428 return -ENOMEM;
1429 }
1430 sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
1431 sig_data->pid = audit_sig_pid;
1432 if (audit_sig_sid) {
1433 memcpy(sig_data->ctx, ctx, len);
1434 security_release_secctx(ctx, len);
1435 }
1436 audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
1437 sig_data, sizeof(*sig_data) + len);
1438 kfree(sig_data);
1439 break;
1440 case AUDIT_TTY_GET: {
1441 struct audit_tty_status s;
1442 unsigned int t;
1443
1444 t = READ_ONCE(current->signal->audit_tty);
1445 s.enabled = t & AUDIT_TTY_ENABLE;
1446 s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1447
1448 audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
1449 break;
1450 }
1451 case AUDIT_TTY_SET: {
1452 struct audit_tty_status s, old;
1453 struct audit_buffer *ab;
1454 unsigned int t;
1455
1456 memset(&s, 0, sizeof(s));
1457 /* guard against past and future API changes */
1458 memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
1459 /* check if new data is valid */
1460 if ((s.enabled != 0 && s.enabled != 1) ||
1461 (s.log_passwd != 0 && s.log_passwd != 1))
1462 err = -EINVAL;
1463
1464 if (err)
1465 t = READ_ONCE(current->signal->audit_tty);
1466 else {
1467 t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD);
1468 t = xchg(&current->signal->audit_tty, t);
1469 }
1470 old.enabled = t & AUDIT_TTY_ENABLE;
1471 old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1472
1473 audit_log_common_recv_msg(audit_context(), &ab,
1474 AUDIT_CONFIG_CHANGE);
1475 audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
1476 " old-log_passwd=%d new-log_passwd=%d res=%d",
1477 old.enabled, s.enabled, old.log_passwd,
1478 s.log_passwd, !err);
1479 audit_log_end(ab);
1480 break;
1481 }
1482 default:
1483 err = -EINVAL;
1484 break;
1485 }
1486
1487 return err < 0 ? err : 0;
1488}
1489
1490/**
1491 * audit_receive - receive messages from a netlink control socket
1492 * @skb: the message buffer
1493 *
1494 * Parse the provided skb and deal with any messages that may be present,
1495 * malformed skbs are discarded.
1496 */
1497static void audit_receive(struct sk_buff *skb)
1498{
1499 struct nlmsghdr *nlh;
1500 /*
1501 * len MUST be signed for nlmsg_next to be able to dec it below 0
1502 * if the nlmsg_len was not aligned
1503 */
1504 int len;
1505 int err;
1506
1507 nlh = nlmsg_hdr(skb);
1508 len = skb->len;
1509
1510 audit_ctl_lock();
1511 while (nlmsg_ok(nlh, len)) {
1512 err = audit_receive_msg(skb, nlh);
1513 /* if err or if this message says it wants a response */
1514 if (err || (nlh->nlmsg_flags & NLM_F_ACK))
1515 netlink_ack(skb, nlh, err, NULL);
1516
1517 nlh = nlmsg_next(nlh, &len);
1518 }
1519 audit_ctl_unlock();
1520}
1521
1522/* Run custom bind function on netlink socket group connect or bind requests. */
1523static int audit_bind(struct net *net, int group)
1524{
1525 if (!capable(CAP_AUDIT_READ))
1526 return -EPERM;
1527
1528 return 0;
1529}
1530
1531static int __net_init audit_net_init(struct net *net)
1532{
1533 struct netlink_kernel_cfg cfg = {
1534 .input = audit_receive,
1535 .bind = audit_bind,
1536 .flags = NL_CFG_F_NONROOT_RECV,
1537 .groups = AUDIT_NLGRP_MAX,
1538 };
1539
1540 struct audit_net *aunet = net_generic(net, audit_net_id);
1541
1542 aunet->sk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
1543 if (aunet->sk == NULL) {
1544 audit_panic("cannot initialize netlink socket in namespace");
1545 return -ENOMEM;
1546 }
1547 aunet->sk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
1548
1549 return 0;
1550}
1551
1552static void __net_exit audit_net_exit(struct net *net)
1553{
1554 struct audit_net *aunet = net_generic(net, audit_net_id);
1555
1556 /* NOTE: you would think that we would want to check the auditd
1557 * connection and potentially reset it here if it lives in this
1558 * namespace, but since the auditd connection tracking struct holds a
1559 * reference to this namespace (see auditd_set()) we are only ever
1560 * going to get here after that connection has been released */
1561
1562 netlink_kernel_release(aunet->sk);
1563}
1564
1565static struct pernet_operations audit_net_ops __net_initdata = {
1566 .init = audit_net_init,
1567 .exit = audit_net_exit,
1568 .id = &audit_net_id,
1569 .size = sizeof(struct audit_net),
1570};
1571
1572/* Initialize audit support at boot time. */
1573static int __init audit_init(void)
1574{
1575 int i;
1576
1577 if (audit_initialized == AUDIT_DISABLED)
1578 return 0;
1579
1580 audit_buffer_cache = kmem_cache_create("audit_buffer",
1581 sizeof(struct audit_buffer),
1582 0, SLAB_PANIC, NULL);
1583
1584 skb_queue_head_init(&audit_queue);
1585 skb_queue_head_init(&audit_retry_queue);
1586 skb_queue_head_init(&audit_hold_queue);
1587
1588 for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
1589 INIT_LIST_HEAD(&audit_inode_hash[i]);
1590
1591 mutex_init(&audit_cmd_mutex.lock);
1592 audit_cmd_mutex.owner = NULL;
1593
1594 pr_info("initializing netlink subsys (%s)\n",
1595 audit_default ? "enabled" : "disabled");
1596 register_pernet_subsys(&audit_net_ops);
1597
1598 audit_initialized = AUDIT_INITIALIZED;
1599
1600 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
1601 if (IS_ERR(kauditd_task)) {
1602 int err = PTR_ERR(kauditd_task);
1603 panic("audit: failed to start the kauditd thread (%d)\n", err);
1604 }
1605
1606 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL,
1607 "state=initialized audit_enabled=%u res=1",
1608 audit_enabled);
1609
1610 return 0;
1611}
1612postcore_initcall(audit_init);
1613
1614/*
1615 * Process kernel command-line parameter at boot time.
1616 * audit={0|off} or audit={1|on}.
1617 */
1618static int __init audit_enable(char *str)
1619{
1620 if (!strcasecmp(str, "off") || !strcmp(str, "0"))
1621 audit_default = AUDIT_OFF;
1622 else if (!strcasecmp(str, "on") || !strcmp(str, "1"))
1623 audit_default = AUDIT_ON;
1624 else {
1625 pr_err("audit: invalid 'audit' parameter value (%s)\n", str);
1626 audit_default = AUDIT_ON;
1627 }
1628
1629 if (audit_default == AUDIT_OFF)
1630 audit_initialized = AUDIT_DISABLED;
1631 if (audit_set_enabled(audit_default))
1632 pr_err("audit: error setting audit state (%d)\n",
1633 audit_default);
1634
1635 pr_info("%s\n", audit_default ?
1636 "enabled (after initialization)" : "disabled (until reboot)");
1637
1638 return 1;
1639}
1640__setup("audit=", audit_enable);
1641
1642/* Process kernel command-line parameter at boot time.
1643 * audit_backlog_limit=<n> */
1644static int __init audit_backlog_limit_set(char *str)
1645{
1646 u32 audit_backlog_limit_arg;
1647
1648 pr_info("audit_backlog_limit: ");
1649 if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
1650 pr_cont("using default of %u, unable to parse %s\n",
1651 audit_backlog_limit, str);
1652 return 1;
1653 }
1654
1655 audit_backlog_limit = audit_backlog_limit_arg;
1656 pr_cont("%d\n", audit_backlog_limit);
1657
1658 return 1;
1659}
1660__setup("audit_backlog_limit=", audit_backlog_limit_set);
1661
1662static void audit_buffer_free(struct audit_buffer *ab)
1663{
1664 if (!ab)
1665 return;
1666
1667 kfree_skb(ab->skb);
1668 kmem_cache_free(audit_buffer_cache, ab);
1669}
1670
1671static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx,
1672 gfp_t gfp_mask, int type)
1673{
1674 struct audit_buffer *ab;
1675
1676 ab = kmem_cache_alloc(audit_buffer_cache, gfp_mask);
1677 if (!ab)
1678 return NULL;
1679
1680 ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
1681 if (!ab->skb)
1682 goto err;
1683 if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0))
1684 goto err;
1685
1686 ab->ctx = ctx;
1687 ab->gfp_mask = gfp_mask;
1688
1689 return ab;
1690
1691err:
1692 audit_buffer_free(ab);
1693 return NULL;
1694}
1695
1696/**
1697 * audit_serial - compute a serial number for the audit record
1698 *
1699 * Compute a serial number for the audit record. Audit records are
1700 * written to user-space as soon as they are generated, so a complete
1701 * audit record may be written in several pieces. The timestamp of the
1702 * record and this serial number are used by the user-space tools to
1703 * determine which pieces belong to the same audit record. The
1704 * (timestamp,serial) tuple is unique for each syscall and is live from
1705 * syscall entry to syscall exit.
1706 *
1707 * NOTE: Another possibility is to store the formatted records off the
1708 * audit context (for those records that have a context), and emit them
1709 * all at syscall exit. However, this could delay the reporting of
1710 * significant errors until syscall exit (or never, if the system
1711 * halts).
1712 */
1713unsigned int audit_serial(void)
1714{
1715 static atomic_t serial = ATOMIC_INIT(0);
1716
1717 return atomic_add_return(1, &serial);
1718}
1719
1720static inline void audit_get_stamp(struct audit_context *ctx,
1721 struct timespec64 *t, unsigned int *serial)
1722{
1723 if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
1724 ktime_get_coarse_real_ts64(t);
1725 *serial = audit_serial();
1726 }
1727}
1728
1729/**
1730 * audit_log_start - obtain an audit buffer
1731 * @ctx: audit_context (may be NULL)
1732 * @gfp_mask: type of allocation
1733 * @type: audit message type
1734 *
1735 * Returns audit_buffer pointer on success or NULL on error.
1736 *
1737 * Obtain an audit buffer. This routine does locking to obtain the
1738 * audit buffer, but then no locking is required for calls to
1739 * audit_log_*format. If the task (ctx) is a task that is currently in a
1740 * syscall, then the syscall is marked as auditable and an audit record
1741 * will be written at syscall exit. If there is no associated task, then
1742 * task context (ctx) should be NULL.
1743 */
1744struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1745 int type)
1746{
1747 struct audit_buffer *ab;
1748 struct timespec64 t;
1749 unsigned int uninitialized_var(serial);
1750
1751 if (audit_initialized != AUDIT_INITIALIZED)
1752 return NULL;
1753
1754 if (unlikely(!audit_filter(type, AUDIT_FILTER_EXCLUDE)))
1755 return NULL;
1756
1757 /* NOTE: don't ever fail/sleep on these two conditions:
1758 * 1. auditd generated record - since we need auditd to drain the
1759 * queue; also, when we are checking for auditd, compare PIDs using
1760 * task_tgid_vnr() since auditd_pid is set in audit_receive_msg()
1761 * using a PID anchored in the caller's namespace
1762 * 2. generator holding the audit_cmd_mutex - we don't want to block
1763 * while holding the mutex */
1764 if (!(auditd_test_task(current) || audit_ctl_owner_current())) {
1765 long stime = audit_backlog_wait_time;
1766
1767 while (audit_backlog_limit &&
1768 (skb_queue_len(&audit_queue) > audit_backlog_limit)) {
1769 /* wake kauditd to try and flush the queue */
1770 wake_up_interruptible(&kauditd_wait);
1771
1772 /* sleep if we are allowed and we haven't exhausted our
1773 * backlog wait limit */
1774 if (gfpflags_allow_blocking(gfp_mask) && (stime > 0)) {
1775 DECLARE_WAITQUEUE(wait, current);
1776
1777 add_wait_queue_exclusive(&audit_backlog_wait,
1778 &wait);
1779 set_current_state(TASK_UNINTERRUPTIBLE);
1780 stime = schedule_timeout(stime);
1781 remove_wait_queue(&audit_backlog_wait, &wait);
1782 } else {
1783 if (audit_rate_check() && printk_ratelimit())
1784 pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
1785 skb_queue_len(&audit_queue),
1786 audit_backlog_limit);
1787 audit_log_lost("backlog limit exceeded");
1788 return NULL;
1789 }
1790 }
1791 }
1792
1793 ab = audit_buffer_alloc(ctx, gfp_mask, type);
1794 if (!ab) {
1795 audit_log_lost("out of memory in audit_log_start");
1796 return NULL;
1797 }
1798
1799 audit_get_stamp(ab->ctx, &t, &serial);
1800 audit_log_format(ab, "audit(%llu.%03lu:%u): ",
1801 (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
1802
1803 return ab;
1804}
1805
1806/**
1807 * audit_expand - expand skb in the audit buffer
1808 * @ab: audit_buffer
1809 * @extra: space to add at tail of the skb
1810 *
1811 * Returns 0 (no space) on failed expansion, or available space if
1812 * successful.
1813 */
1814static inline int audit_expand(struct audit_buffer *ab, int extra)
1815{
1816 struct sk_buff *skb = ab->skb;
1817 int oldtail = skb_tailroom(skb);
1818 int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1819 int newtail = skb_tailroom(skb);
1820
1821 if (ret < 0) {
1822 audit_log_lost("out of memory in audit_expand");
1823 return 0;
1824 }
1825
1826 skb->truesize += newtail - oldtail;
1827 return newtail;
1828}
1829
1830/*
1831 * Format an audit message into the audit buffer. If there isn't enough
1832 * room in the audit buffer, more room will be allocated and vsnprint
1833 * will be called a second time. Currently, we assume that a printk
1834 * can't format message larger than 1024 bytes, so we don't either.
1835 */
1836static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1837 va_list args)
1838{
1839 int len, avail;
1840 struct sk_buff *skb;
1841 va_list args2;
1842
1843 if (!ab)
1844 return;
1845
1846 BUG_ON(!ab->skb);
1847 skb = ab->skb;
1848 avail = skb_tailroom(skb);
1849 if (avail == 0) {
1850 avail = audit_expand(ab, AUDIT_BUFSIZ);
1851 if (!avail)
1852 goto out;
1853 }
1854 va_copy(args2, args);
1855 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1856 if (len >= avail) {
1857 /* The printk buffer is 1024 bytes long, so if we get
1858 * here and AUDIT_BUFSIZ is at least 1024, then we can
1859 * log everything that printk could have logged. */
1860 avail = audit_expand(ab,
1861 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1862 if (!avail)
1863 goto out_va_end;
1864 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1865 }
1866 if (len > 0)
1867 skb_put(skb, len);
1868out_va_end:
1869 va_end(args2);
1870out:
1871 return;
1872}
1873
1874/**
1875 * audit_log_format - format a message into the audit buffer.
1876 * @ab: audit_buffer
1877 * @fmt: format string
1878 * @...: optional parameters matching @fmt string
1879 *
1880 * All the work is done in audit_log_vformat.
1881 */
1882void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1883{
1884 va_list args;
1885
1886 if (!ab)
1887 return;
1888 va_start(args, fmt);
1889 audit_log_vformat(ab, fmt, args);
1890 va_end(args);
1891}
1892
1893/**
1894 * audit_log_n_hex - convert a buffer to hex and append it to the audit skb
1895 * @ab: the audit_buffer
1896 * @buf: buffer to convert to hex
1897 * @len: length of @buf to be converted
1898 *
1899 * No return value; failure to expand is silently ignored.
1900 *
1901 * This function will take the passed buf and convert it into a string of
1902 * ascii hex digits. The new string is placed onto the skb.
1903 */
1904void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
1905 size_t len)
1906{
1907 int i, avail, new_len;
1908 unsigned char *ptr;
1909 struct sk_buff *skb;
1910
1911 if (!ab)
1912 return;
1913
1914 BUG_ON(!ab->skb);
1915 skb = ab->skb;
1916 avail = skb_tailroom(skb);
1917 new_len = len<<1;
1918 if (new_len >= avail) {
1919 /* Round the buffer request up to the next multiple */
1920 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1921 avail = audit_expand(ab, new_len);
1922 if (!avail)
1923 return;
1924 }
1925
1926 ptr = skb_tail_pointer(skb);
1927 for (i = 0; i < len; i++)
1928 ptr = hex_byte_pack_upper(ptr, buf[i]);
1929 *ptr = 0;
1930 skb_put(skb, len << 1); /* new string is twice the old string */
1931}
1932
1933/*
1934 * Format a string of no more than slen characters into the audit buffer,
1935 * enclosed in quote marks.
1936 */
1937void audit_log_n_string(struct audit_buffer *ab, const char *string,
1938 size_t slen)
1939{
1940 int avail, new_len;
1941 unsigned char *ptr;
1942 struct sk_buff *skb;
1943
1944 if (!ab)
1945 return;
1946
1947 BUG_ON(!ab->skb);
1948 skb = ab->skb;
1949 avail = skb_tailroom(skb);
1950 new_len = slen + 3; /* enclosing quotes + null terminator */
1951 if (new_len > avail) {
1952 avail = audit_expand(ab, new_len);
1953 if (!avail)
1954 return;
1955 }
1956 ptr = skb_tail_pointer(skb);
1957 *ptr++ = '"';
1958 memcpy(ptr, string, slen);
1959 ptr += slen;
1960 *ptr++ = '"';
1961 *ptr = 0;
1962 skb_put(skb, slen + 2); /* don't include null terminator */
1963}
1964
1965/**
1966 * audit_string_contains_control - does a string need to be logged in hex
1967 * @string: string to be checked
1968 * @len: max length of the string to check
1969 */
1970bool audit_string_contains_control(const char *string, size_t len)
1971{
1972 const unsigned char *p;
1973 for (p = string; p < (const unsigned char *)string + len; p++) {
1974 if (*p == '"' || *p < 0x21 || *p > 0x7e)
1975 return true;
1976 }
1977 return false;
1978}
1979
1980/**
1981 * audit_log_n_untrustedstring - log a string that may contain random characters
1982 * @ab: audit_buffer
1983 * @len: length of string (not including trailing null)
1984 * @string: string to be logged
1985 *
1986 * This code will escape a string that is passed to it if the string
1987 * contains a control character, unprintable character, double quote mark,
1988 * or a space. Unescaped strings will start and end with a double quote mark.
1989 * Strings that are escaped are printed in hex (2 digits per char).
1990 *
1991 * The caller specifies the number of characters in the string to log, which may
1992 * or may not be the entire string.
1993 */
1994void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
1995 size_t len)
1996{
1997 if (audit_string_contains_control(string, len))
1998 audit_log_n_hex(ab, string, len);
1999 else
2000 audit_log_n_string(ab, string, len);
2001}
2002
2003/**
2004 * audit_log_untrustedstring - log a string that may contain random characters
2005 * @ab: audit_buffer
2006 * @string: string to be logged
2007 *
2008 * Same as audit_log_n_untrustedstring(), except that strlen is used to
2009 * determine string length.
2010 */
2011void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
2012{
2013 audit_log_n_untrustedstring(ab, string, strlen(string));
2014}
2015
2016/* This is a helper-function to print the escaped d_path */
2017void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
2018 const struct path *path)
2019{
2020 char *p, *pathname;
2021
2022 if (prefix)
2023 audit_log_format(ab, "%s", prefix);
2024
2025 /* We will allow 11 spaces for ' (deleted)' to be appended */
2026 pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
2027 if (!pathname) {
2028 audit_log_string(ab, "<no_memory>");
2029 return;
2030 }
2031 p = d_path(path, pathname, PATH_MAX+11);
2032 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
2033 /* FIXME: can we save some information here? */
2034 audit_log_string(ab, "<too_long>");
2035 } else
2036 audit_log_untrustedstring(ab, p);
2037 kfree(pathname);
2038}
2039
2040void audit_log_session_info(struct audit_buffer *ab)
2041{
2042 unsigned int sessionid = audit_get_sessionid(current);
2043 uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
2044
2045 audit_log_format(ab, "auid=%u ses=%u", auid, sessionid);
2046}
2047
2048void audit_log_key(struct audit_buffer *ab, char *key)
2049{
2050 audit_log_format(ab, " key=");
2051 if (key)
2052 audit_log_untrustedstring(ab, key);
2053 else
2054 audit_log_format(ab, "(null)");
2055}
2056
2057int audit_log_task_context(struct audit_buffer *ab)
2058{
2059 char *ctx = NULL;
2060 unsigned len;
2061 int error;
2062 u32 sid;
2063
2064 security_task_getsecid(current, &sid);
2065 if (!sid)
2066 return 0;
2067
2068 error = security_secid_to_secctx(sid, &ctx, &len);
2069 if (error) {
2070 if (error != -EINVAL)
2071 goto error_path;
2072 return 0;
2073 }
2074
2075 audit_log_format(ab, " subj=%s", ctx);
2076 security_release_secctx(ctx, len);
2077 return 0;
2078
2079error_path:
2080 audit_panic("error in audit_log_task_context");
2081 return error;
2082}
2083EXPORT_SYMBOL(audit_log_task_context);
2084
2085void audit_log_d_path_exe(struct audit_buffer *ab,
2086 struct mm_struct *mm)
2087{
2088 struct file *exe_file;
2089
2090 if (!mm)
2091 goto out_null;
2092
2093 exe_file = get_mm_exe_file(mm);
2094 if (!exe_file)
2095 goto out_null;
2096
2097 audit_log_d_path(ab, " exe=", &exe_file->f_path);
2098 fput(exe_file);
2099 return;
2100out_null:
2101 audit_log_format(ab, " exe=(null)");
2102}
2103
2104struct tty_struct *audit_get_tty(void)
2105{
2106 struct tty_struct *tty = NULL;
2107 unsigned long flags;
2108
2109 spin_lock_irqsave(&current->sighand->siglock, flags);
2110 if (current->signal)
2111 tty = tty_kref_get(current->signal->tty);
2112 spin_unlock_irqrestore(&current->sighand->siglock, flags);
2113 return tty;
2114}
2115
2116void audit_put_tty(struct tty_struct *tty)
2117{
2118 tty_kref_put(tty);
2119}
2120
2121void audit_log_task_info(struct audit_buffer *ab)
2122{
2123 const struct cred *cred;
2124 char comm[sizeof(current->comm)];
2125 struct tty_struct *tty;
2126
2127 if (!ab)
2128 return;
2129
2130 cred = current_cred();
2131 tty = audit_get_tty();
2132 audit_log_format(ab,
2133 " ppid=%d pid=%d auid=%u uid=%u gid=%u"
2134 " euid=%u suid=%u fsuid=%u"
2135 " egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
2136 task_ppid_nr(current),
2137 task_tgid_nr(current),
2138 from_kuid(&init_user_ns, audit_get_loginuid(current)),
2139 from_kuid(&init_user_ns, cred->uid),
2140 from_kgid(&init_user_ns, cred->gid),
2141 from_kuid(&init_user_ns, cred->euid),
2142 from_kuid(&init_user_ns, cred->suid),
2143 from_kuid(&init_user_ns, cred->fsuid),
2144 from_kgid(&init_user_ns, cred->egid),
2145 from_kgid(&init_user_ns, cred->sgid),
2146 from_kgid(&init_user_ns, cred->fsgid),
2147 tty ? tty_name(tty) : "(none)",
2148 audit_get_sessionid(current));
2149 audit_put_tty(tty);
2150 audit_log_format(ab, " comm=");
2151 audit_log_untrustedstring(ab, get_task_comm(comm, current));
2152 audit_log_d_path_exe(ab, current->mm);
2153 audit_log_task_context(ab);
2154}
2155EXPORT_SYMBOL(audit_log_task_info);
2156
2157/**
2158 * audit_log_link_denied - report a link restriction denial
2159 * @operation: specific link operation
2160 */
2161void audit_log_link_denied(const char *operation)
2162{
2163 struct audit_buffer *ab;
2164
2165 if (!audit_enabled || audit_dummy_context())
2166 return;
2167
2168 /* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */
2169 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_ANOM_LINK);
2170 if (!ab)
2171 return;
2172 audit_log_format(ab, "op=%s", operation);
2173 audit_log_task_info(ab);
2174 audit_log_format(ab, " res=0");
2175 audit_log_end(ab);
2176}
2177
2178/* global counter which is incremented every time something logs in */
2179static atomic_t session_id = ATOMIC_INIT(0);
2180
2181static int audit_set_loginuid_perm(kuid_t loginuid)
2182{
2183 /* if we are unset, we don't need privs */
2184 if (!audit_loginuid_set(current))
2185 return 0;
2186 /* if AUDIT_FEATURE_LOGINUID_IMMUTABLE means never ever allow a change*/
2187 if (is_audit_feature_set(AUDIT_FEATURE_LOGINUID_IMMUTABLE))
2188 return -EPERM;
2189 /* it is set, you need permission */
2190 if (!capable(CAP_AUDIT_CONTROL))
2191 return -EPERM;
2192 /* reject if this is not an unset and we don't allow that */
2193 if (is_audit_feature_set(AUDIT_FEATURE_ONLY_UNSET_LOGINUID)
2194 && uid_valid(loginuid))
2195 return -EPERM;
2196 return 0;
2197}
2198
2199static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
2200 unsigned int oldsessionid,
2201 unsigned int sessionid, int rc)
2202{
2203 struct audit_buffer *ab;
2204 uid_t uid, oldloginuid, loginuid;
2205 struct tty_struct *tty;
2206
2207 if (!audit_enabled)
2208 return;
2209
2210 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_LOGIN);
2211 if (!ab)
2212 return;
2213
2214 uid = from_kuid(&init_user_ns, task_uid(current));
2215 oldloginuid = from_kuid(&init_user_ns, koldloginuid);
2216 loginuid = from_kuid(&init_user_ns, kloginuid),
2217 tty = audit_get_tty();
2218
2219 audit_log_format(ab, "pid=%d uid=%u", task_tgid_nr(current), uid);
2220 audit_log_task_context(ab);
2221 audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",
2222 oldloginuid, loginuid, tty ? tty_name(tty) : "(none)",
2223 oldsessionid, sessionid, !rc);
2224 audit_put_tty(tty);
2225 audit_log_end(ab);
2226}
2227
2228/**
2229 * audit_set_loginuid - set current task's loginuid
2230 * @loginuid: loginuid value
2231 *
2232 * Returns 0.
2233 *
2234 * Called (set) from fs/proc/base.c::proc_loginuid_write().
2235 */
2236int audit_set_loginuid(kuid_t loginuid)
2237{
2238 unsigned int oldsessionid, sessionid = AUDIT_SID_UNSET;
2239 kuid_t oldloginuid;
2240 int rc;
2241
2242 oldloginuid = audit_get_loginuid(current);
2243 oldsessionid = audit_get_sessionid(current);
2244
2245 rc = audit_set_loginuid_perm(loginuid);
2246 if (rc)
2247 goto out;
2248
2249 /* are we setting or clearing? */
2250 if (uid_valid(loginuid)) {
2251 sessionid = (unsigned int)atomic_inc_return(&session_id);
2252 if (unlikely(sessionid == AUDIT_SID_UNSET))
2253 sessionid = (unsigned int)atomic_inc_return(&session_id);
2254 }
2255
2256 current->sessionid = sessionid;
2257 current->loginuid = loginuid;
2258out:
2259 audit_log_set_loginuid(oldloginuid, loginuid, oldsessionid, sessionid, rc);
2260 return rc;
2261}
2262
2263/**
2264 * audit_signal_info - record signal info for shutting down audit subsystem
2265 * @sig: signal value
2266 * @t: task being signaled
2267 *
2268 * If the audit subsystem is being terminated, record the task (pid)
2269 * and uid that is doing that.
2270 */
2271int audit_signal_info(int sig, struct task_struct *t)
2272{
2273 kuid_t uid = current_uid(), auid;
2274
2275 if (auditd_test_task(t) &&
2276 (sig == SIGTERM || sig == SIGHUP ||
2277 sig == SIGUSR1 || sig == SIGUSR2)) {
2278 audit_sig_pid = task_tgid_nr(current);
2279 auid = audit_get_loginuid(current);
2280 if (uid_valid(auid))
2281 audit_sig_uid = auid;
2282 else
2283 audit_sig_uid = uid;
2284 security_task_getsecid(current, &audit_sig_sid);
2285 }
2286
2287 return audit_signal_info_syscall(t);
2288}
2289
2290/**
2291 * audit_log_end - end one audit record
2292 * @ab: the audit_buffer
2293 *
2294 * We can not do a netlink send inside an irq context because it blocks (last
2295 * arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a
2296 * queue and a tasklet is scheduled to remove them from the queue outside the
2297 * irq context. May be called in any context.
2298 */
2299void audit_log_end(struct audit_buffer *ab)
2300{
2301 struct sk_buff *skb;
2302 struct nlmsghdr *nlh;
2303
2304 if (!ab)
2305 return;
2306
2307 if (audit_rate_check()) {
2308 skb = ab->skb;
2309 ab->skb = NULL;
2310
2311 /* setup the netlink header, see the comments in
2312 * kauditd_send_multicast_skb() for length quirks */
2313 nlh = nlmsg_hdr(skb);
2314 nlh->nlmsg_len = skb->len - NLMSG_HDRLEN;
2315
2316 /* queue the netlink packet and poke the kauditd thread */
2317 skb_queue_tail(&audit_queue, skb);
2318 wake_up_interruptible(&kauditd_wait);
2319 } else
2320 audit_log_lost("rate limit exceeded");
2321
2322 audit_buffer_free(ab);
2323}
2324
2325/**
2326 * audit_log - Log an audit record
2327 * @ctx: audit context
2328 * @gfp_mask: type of allocation
2329 * @type: audit message type
2330 * @fmt: format string to use
2331 * @...: variable parameters matching the format string
2332 *
2333 * This is a convenience function that calls audit_log_start,
2334 * audit_log_vformat, and audit_log_end. It may be called
2335 * in any context.
2336 */
2337void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
2338 const char *fmt, ...)
2339{
2340 struct audit_buffer *ab;
2341 va_list args;
2342
2343 ab = audit_log_start(ctx, gfp_mask, type);
2344 if (ab) {
2345 va_start(args, fmt);
2346 audit_log_vformat(ab, fmt, args);
2347 va_end(args);
2348 audit_log_end(ab);
2349 }
2350}
2351
2352EXPORT_SYMBOL(audit_log_start);
2353EXPORT_SYMBOL(audit_log_end);
2354EXPORT_SYMBOL(audit_log_format);
2355EXPORT_SYMBOL(audit_log);