1/* audit.c -- Auditing support
2 * Gateway between the kernel (e.g., selinux) and the user-space audit daemon.
3 * System-call specific features have moved to auditsc.c
4 *
5 * Copyright 2003-2007 Red Hat Inc., Durham, North Carolina.
6 * All Rights Reserved.
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 *
22 * Written by Rickard E. (Rik) Faith <faith@redhat.com>
23 *
24 * Goals: 1) Integrate fully with Security Modules.
25 * 2) Minimal run-time overhead:
26 * a) Minimal when syscall auditing is disabled (audit_enable=0).
27 * b) Small when syscall auditing is enabled and no audit record
28 * is generated (defer as much work as possible to record
29 * generation time):
30 * i) context is allocated,
31 * ii) names from getname are stored without a copy, and
32 * iii) inode information stored from path_lookup.
33 * 3) Ability to disable syscall auditing at boot time (audit=0).
34 * 4) Usable by other parts of the kernel (if audit_log* is called,
35 * then a syscall record will be generated automatically for the
36 * current syscall).
37 * 5) Netlink interface to user-space.
38 * 6) Support low-overhead kernel-based filtering to minimize the
39 * information that must be passed to user-space.
40 *
41 * Audit userspace, documentation, tests, and bug/issue trackers:
42 * https://github.com/linux-audit
43 */
44
45#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
46
47#include <linux/file.h>
48#include <linux/init.h>
49#include <linux/types.h>
50#include <linux/atomic.h>
51#include <linux/mm.h>
52#include <linux/export.h>
53#include <linux/slab.h>
54#include <linux/err.h>
55#include <linux/kthread.h>
56#include <linux/kernel.h>
57#include <linux/syscalls.h>
58#include <linux/spinlock.h>
59#include <linux/rcupdate.h>
60#include <linux/mutex.h>
61#include <linux/gfp.h>
62#include <linux/pid.h>
63
64#include <linux/audit.h>
65
66#include <net/sock.h>
67#include <net/netlink.h>
68#include <linux/skbuff.h>
69#ifdef CONFIG_SECURITY
70#include <linux/security.h>
71#endif
72#include <linux/freezer.h>
73#include <linux/pid_namespace.h>
74#include <net/netns/generic.h>
75
76#include "audit.h"
77
78/* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
79 * (Initialization happens after skb_init is called.) */
80#define AUDIT_DISABLED -1
81#define AUDIT_UNINITIALIZED 0
82#define AUDIT_INITIALIZED 1
83static int audit_initialized;
84
85u32 audit_enabled = AUDIT_OFF;
86bool audit_ever_enabled = !!AUDIT_OFF;
87
88EXPORT_SYMBOL_GPL(audit_enabled);
89
90/* Default state when kernel boots without any parameters. */
91static u32 audit_default = AUDIT_OFF;
92
93/* If auditing cannot proceed, audit_failure selects what happens. */
94static u32 audit_failure = AUDIT_FAIL_PRINTK;
95
96/* private audit network namespace index */
97static unsigned int audit_net_id;
98
99/**
100 * struct audit_net - audit private network namespace data
101 * @sk: communication socket
102 */
103struct audit_net {
104 struct sock *sk;
105};
106
107/**
108 * struct auditd_connection - kernel/auditd connection state
109 * @pid: auditd PID
110 * @portid: netlink portid
111 * @net: the associated network namespace
112 * @rcu: RCU head
113 *
114 * Description:
115 * This struct is RCU protected; you must either hold the RCU lock for reading
116 * or the associated spinlock for writing.
117 */
118static struct auditd_connection {
119 struct pid *pid;
120 u32 portid;
121 struct net *net;
122 struct rcu_head rcu;
123} *auditd_conn = NULL;
124static DEFINE_SPINLOCK(auditd_conn_lock);
125
126/* If audit_rate_limit is non-zero, limit the rate of sending audit records
127 * to that number per second. This prevents DoS attacks, but results in
128 * audit records being dropped. */
129static u32 audit_rate_limit;
130
131/* Number of outstanding audit_buffers allowed.
132 * When set to zero, this means unlimited. */
133static u32 audit_backlog_limit = 64;
134#define AUDIT_BACKLOG_WAIT_TIME (60 * HZ)
135static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
136
137/* The identity of the user shutting down the audit system. */
138kuid_t audit_sig_uid = INVALID_UID;
139pid_t audit_sig_pid = -1;
140u32 audit_sig_sid = 0;
141
142/* Records can be lost in several ways:
143 0) [suppressed in audit_alloc]
144 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
145 2) out of memory in audit_log_move [alloc_skb]
146 3) suppressed due to audit_rate_limit
147 4) suppressed due to audit_backlog_limit
148*/
149static atomic_t audit_lost = ATOMIC_INIT(0);
150
151/* Hash for inode-based rules */
152struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
153
154static struct kmem_cache *audit_buffer_cache;
155
156/* queue msgs to send via kauditd_task */
157static struct sk_buff_head audit_queue;
158/* queue msgs due to temporary unicast send problems */
159static struct sk_buff_head audit_retry_queue;
160/* queue msgs waiting for new auditd connection */
161static struct sk_buff_head audit_hold_queue;
162
163/* queue servicing thread */
164static struct task_struct *kauditd_task;
165static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
166
167/* waitqueue for callers who are blocked on the audit backlog */
168static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
169
170static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION,
171 .mask = -1,
172 .features = 0,
173 .lock = 0,};
174
175static char *audit_feature_names[2] = {
176 "only_unset_loginuid",
177 "loginuid_immutable",
178};
179
180/**
181 * struct audit_ctl_mutex - serialize requests from userspace
182 * @lock: the mutex used for locking
183 * @owner: the task which owns the lock
184 *
185 * Description:
186 * This is the lock struct used to ensure we only process userspace requests
187 * in an orderly fashion. We can't simply use a mutex/lock here because we
188 * need to track lock ownership so we don't end up blocking the lock owner in
189 * audit_log_start() or similar.
190 */
191static struct audit_ctl_mutex {
192 struct mutex lock;
193 void *owner;
194} audit_cmd_mutex;
195
196/* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
197 * audit records. Since printk uses a 1024 byte buffer, this buffer
198 * should be at least that large. */
199#define AUDIT_BUFSIZ 1024
200
201/* The audit_buffer is used when formatting an audit record. The caller
202 * locks briefly to get the record off the freelist or to allocate the
203 * buffer, and locks briefly to send the buffer to the netlink layer or
204 * to place it on a transmit queue. Multiple audit_buffers can be in
205 * use simultaneously. */
206struct audit_buffer {
207 struct sk_buff *skb; /* formatted skb ready to send */
208 struct audit_context *ctx; /* NULL or associated context */
209 gfp_t gfp_mask;
210};
211
212struct audit_reply {
213 __u32 portid;
214 struct net *net;
215 struct sk_buff *skb;
216};
217
218/**
219 * auditd_test_task - Check to see if a given task is an audit daemon
220 * @task: the task to check
221 *
222 * Description:
223 * Return 1 if the task is a registered audit daemon, 0 otherwise.
224 */
225int auditd_test_task(struct task_struct *task)
226{
227 int rc;
228 struct auditd_connection *ac;
229
230 rcu_read_lock();
231 ac = rcu_dereference(auditd_conn);
232 rc = (ac && ac->pid == task_tgid(task) ? 1 : 0);
233 rcu_read_unlock();
234
235 return rc;
236}
237
238/**
239 * audit_ctl_lock - Take the audit control lock
240 */
241void audit_ctl_lock(void)
242{
243 mutex_lock(&audit_cmd_mutex.lock);
244 audit_cmd_mutex.owner = current;
245}
246
247/**
248 * audit_ctl_unlock - Drop the audit control lock
249 */
250void audit_ctl_unlock(void)
251{
252 audit_cmd_mutex.owner = NULL;
253 mutex_unlock(&audit_cmd_mutex.lock);
254}
255
256/**
257 * audit_ctl_owner_current - Test to see if the current task owns the lock
258 *
259 * Description:
260 * Return true if the current task owns the audit control lock, false if it
261 * doesn't own the lock.
262 */
263static bool audit_ctl_owner_current(void)
264{
265 return (current == audit_cmd_mutex.owner);
266}
267
268/**
269 * auditd_pid_vnr - Return the auditd PID relative to the namespace
270 *
271 * Description:
272 * Returns the PID in relation to the namespace, 0 on failure.
273 */
274static pid_t auditd_pid_vnr(void)
275{
276 pid_t pid;
277 const struct auditd_connection *ac;
278
279 rcu_read_lock();
280 ac = rcu_dereference(auditd_conn);
281 if (!ac || !ac->pid)
282 pid = 0;
283 else
284 pid = pid_vnr(ac->pid);
285 rcu_read_unlock();
286
287 return pid;
288}
289
290/**
291 * audit_get_sk - Return the audit socket for the given network namespace
292 * @net: the destination network namespace
293 *
294 * Description:
295 * Returns the sock pointer if valid, NULL otherwise. The caller must ensure
296 * that a reference is held for the network namespace while the sock is in use.
297 */
298static struct sock *audit_get_sk(const struct net *net)
299{
300 struct audit_net *aunet;
301
302 if (!net)
303 return NULL;
304
305 aunet = net_generic(net, audit_net_id);
306 return aunet->sk;
307}
308
309void audit_panic(const char *message)
310{
311 switch (audit_failure) {
312 case AUDIT_FAIL_SILENT:
313 break;
314 case AUDIT_FAIL_PRINTK:
315 if (printk_ratelimit())
316 pr_err("%s\n", message);
317 break;
318 case AUDIT_FAIL_PANIC:
319 panic("audit: %s\n", message);
320 break;
321 }
322}
323
324static inline int audit_rate_check(void)
325{
326 static unsigned long last_check = 0;
327 static int messages = 0;
328 static DEFINE_SPINLOCK(lock);
329 unsigned long flags;
330 unsigned long now;
331 unsigned long elapsed;
332 int retval = 0;
333
334 if (!audit_rate_limit) return 1;
335
336 spin_lock_irqsave(&lock, flags);
337 if (++messages < audit_rate_limit) {
338 retval = 1;
339 } else {
340 now = jiffies;
341 elapsed = now - last_check;
342 if (elapsed > HZ) {
343 last_check = now;
344 messages = 0;
345 retval = 1;
346 }
347 }
348 spin_unlock_irqrestore(&lock, flags);
349
350 return retval;
351}
352
353/**
354 * audit_log_lost - conditionally log lost audit message event
355 * @message: the message stating reason for lost audit message
356 *
357 * Emit at least 1 message per second, even if audit_rate_check is
358 * throttling.
359 * Always increment the lost messages counter.
360*/
361void audit_log_lost(const char *message)
362{
363 static unsigned long last_msg = 0;
364 static DEFINE_SPINLOCK(lock);
365 unsigned long flags;
366 unsigned long now;
367 int print;
368
369 atomic_inc(&audit_lost);
370
371 print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
372
373 if (!print) {
374 spin_lock_irqsave(&lock, flags);
375 now = jiffies;
376 if (now - last_msg > HZ) {
377 print = 1;
378 last_msg = now;
379 }
380 spin_unlock_irqrestore(&lock, flags);
381 }
382
383 if (print) {
384 if (printk_ratelimit())
385 pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
386 atomic_read(&audit_lost),
387 audit_rate_limit,
388 audit_backlog_limit);
389 audit_panic(message);
390 }
391}
392
393static int audit_log_config_change(char *function_name, u32 new, u32 old,
394 int allow_changes)
395{
396 struct audit_buffer *ab;
397 int rc = 0;
398
399 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
400 if (unlikely(!ab))
401 return rc;
402 audit_log_format(ab, "op=set %s=%u old=%u ", function_name, new, old);
403 audit_log_session_info(ab);
404 rc = audit_log_task_context(ab);
405 if (rc)
406 allow_changes = 0; /* Something weird, deny request */
407 audit_log_format(ab, " res=%d", allow_changes);
408 audit_log_end(ab);
409 return rc;
410}
411
412static int audit_do_config_change(char *function_name, u32 *to_change, u32 new)
413{
414 int allow_changes, rc = 0;
415 u32 old = *to_change;
416
417 /* check if we are locked */
418 if (audit_enabled == AUDIT_LOCKED)
419 allow_changes = 0;
420 else
421 allow_changes = 1;
422
423 if (audit_enabled != AUDIT_OFF) {
424 rc = audit_log_config_change(function_name, new, old, allow_changes);
425 if (rc)
426 allow_changes = 0;
427 }
428
429 /* If we are allowed, make the change */
430 if (allow_changes == 1)
431 *to_change = new;
432 /* Not allowed, update reason */
433 else if (rc == 0)
434 rc = -EPERM;
435 return rc;
436}
437
438static int audit_set_rate_limit(u32 limit)
439{
440 return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit);
441}
442
443static int audit_set_backlog_limit(u32 limit)
444{
445 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit);
446}
447
448static int audit_set_backlog_wait_time(u32 timeout)
449{
450 return audit_do_config_change("audit_backlog_wait_time",
451 &audit_backlog_wait_time, timeout);
452}
453
454static int audit_set_enabled(u32 state)
455{
456 int rc;
457 if (state > AUDIT_LOCKED)
458 return -EINVAL;
459
460 rc = audit_do_config_change("audit_enabled", &audit_enabled, state);
461 if (!rc)
462 audit_ever_enabled |= !!state;
463
464 return rc;
465}
466
467static int audit_set_failure(u32 state)
468{
469 if (state != AUDIT_FAIL_SILENT
470 && state != AUDIT_FAIL_PRINTK
471 && state != AUDIT_FAIL_PANIC)
472 return -EINVAL;
473
474 return audit_do_config_change("audit_failure", &audit_failure, state);
475}
476
477/**
478 * auditd_conn_free - RCU helper to release an auditd connection struct
479 * @rcu: RCU head
480 *
481 * Description:
482 * Drop any references inside the auditd connection tracking struct and free
483 * the memory.
484 */
485static void auditd_conn_free(struct rcu_head *rcu)
486{
487 struct auditd_connection *ac;
488
489 ac = container_of(rcu, struct auditd_connection, rcu);
490 put_pid(ac->pid);
491 put_net(ac->net);
492 kfree(ac);
493}
494
495/**
496 * auditd_set - Set/Reset the auditd connection state
497 * @pid: auditd PID
498 * @portid: auditd netlink portid
499 * @net: auditd network namespace pointer
500 *
501 * Description:
502 * This function will obtain and drop network namespace references as
503 * necessary. Returns zero on success, negative values on failure.
504 */
505static int auditd_set(struct pid *pid, u32 portid, struct net *net)
506{
507 unsigned long flags;
508 struct auditd_connection *ac_old, *ac_new;
509
510 if (!pid || !net)
511 return -EINVAL;
512
513 ac_new = kzalloc(sizeof(*ac_new), GFP_KERNEL);
514 if (!ac_new)
515 return -ENOMEM;
516 ac_new->pid = get_pid(pid);
517 ac_new->portid = portid;
518 ac_new->net = get_net(net);
519
520 spin_lock_irqsave(&auditd_conn_lock, flags);
521 ac_old = rcu_dereference_protected(auditd_conn,
522 lockdep_is_held(&auditd_conn_lock));
523 rcu_assign_pointer(auditd_conn, ac_new);
524 spin_unlock_irqrestore(&auditd_conn_lock, flags);
525
526 if (ac_old)
527 call_rcu(&ac_old->rcu, auditd_conn_free);
528
529 return 0;
530}
531
532/**
533 * kauditd_print_skb - Print the audit record to the ring buffer
534 * @skb: audit record
535 *
536 * Whatever the reason, this packet may not make it to the auditd connection
537 * so write it via printk so the information isn't completely lost.
538 */
539static void kauditd_printk_skb(struct sk_buff *skb)
540{
541 struct nlmsghdr *nlh = nlmsg_hdr(skb);
542 char *data = nlmsg_data(nlh);
543
544 if (nlh->nlmsg_type != AUDIT_EOE && printk_ratelimit())
545 pr_notice("type=%d %s\n", nlh->nlmsg_type, data);
546}
547
548/**
549 * kauditd_rehold_skb - Handle a audit record send failure in the hold queue
550 * @skb: audit record
551 *
552 * Description:
553 * This should only be used by the kauditd_thread when it fails to flush the
554 * hold queue.
555 */
556static void kauditd_rehold_skb(struct sk_buff *skb)
557{
558 /* put the record back in the queue at the same place */
559 skb_queue_head(&audit_hold_queue, skb);
560}
561
562/**
563 * kauditd_hold_skb - Queue an audit record, waiting for auditd
564 * @skb: audit record
565 *
566 * Description:
567 * Queue the audit record, waiting for an instance of auditd. When this
568 * function is called we haven't given up yet on sending the record, but things
569 * are not looking good. The first thing we want to do is try to write the
570 * record via printk and then see if we want to try and hold on to the record
571 * and queue it, if we have room. If we want to hold on to the record, but we
572 * don't have room, record a record lost message.
573 */
574static void kauditd_hold_skb(struct sk_buff *skb)
575{
576 /* at this point it is uncertain if we will ever send this to auditd so
577 * try to send the message via printk before we go any further */
578 kauditd_printk_skb(skb);
579
580 /* can we just silently drop the message? */
581 if (!audit_default) {
582 kfree_skb(skb);
583 return;
584 }
585
586 /* if we have room, queue the message */
587 if (!audit_backlog_limit ||
588 skb_queue_len(&audit_hold_queue) < audit_backlog_limit) {
589 skb_queue_tail(&audit_hold_queue, skb);
590 return;
591 }
592
593 /* we have no other options - drop the message */
594 audit_log_lost("kauditd hold queue overflow");
595 kfree_skb(skb);
596}
597
598/**
599 * kauditd_retry_skb - Queue an audit record, attempt to send again to auditd
600 * @skb: audit record
601 *
602 * Description:
603 * Not as serious as kauditd_hold_skb() as we still have a connected auditd,
604 * but for some reason we are having problems sending it audit records so
605 * queue the given record and attempt to resend.
606 */
607static void kauditd_retry_skb(struct sk_buff *skb)
608{
609 /* NOTE: because records should only live in the retry queue for a
610 * short period of time, before either being sent or moved to the hold
611 * queue, we don't currently enforce a limit on this queue */
612 skb_queue_tail(&audit_retry_queue, skb);
613}
614
615/**
616 * auditd_reset - Disconnect the auditd connection
617 * @ac: auditd connection state
618 *
619 * Description:
620 * Break the auditd/kauditd connection and move all the queued records into the
621 * hold queue in case auditd reconnects. It is important to note that the @ac
622 * pointer should never be dereferenced inside this function as it may be NULL
623 * or invalid, you can only compare the memory address! If @ac is NULL then
624 * the connection will always be reset.
625 */
626static void auditd_reset(const struct auditd_connection *ac)
627{
628 unsigned long flags;
629 struct sk_buff *skb;
630 struct auditd_connection *ac_old;
631
632 /* if it isn't already broken, break the connection */
633 spin_lock_irqsave(&auditd_conn_lock, flags);
634 ac_old = rcu_dereference_protected(auditd_conn,
635 lockdep_is_held(&auditd_conn_lock));
636 if (ac && ac != ac_old) {
637 /* someone already registered a new auditd connection */
638 spin_unlock_irqrestore(&auditd_conn_lock, flags);
639 return;
640 }
641 rcu_assign_pointer(auditd_conn, NULL);
642 spin_unlock_irqrestore(&auditd_conn_lock, flags);
643
644 if (ac_old)
645 call_rcu(&ac_old->rcu, auditd_conn_free);
646
647 /* flush the retry queue to the hold queue, but don't touch the main
648 * queue since we need to process that normally for multicast */
649 while ((skb = skb_dequeue(&audit_retry_queue)))
650 kauditd_hold_skb(skb);
651}
652
653/**
654 * auditd_send_unicast_skb - Send a record via unicast to auditd
655 * @skb: audit record
656 *
657 * Description:
658 * Send a skb to the audit daemon, returns positive/zero values on success and
659 * negative values on failure; in all cases the skb will be consumed by this
660 * function. If the send results in -ECONNREFUSED the connection with auditd
661 * will be reset. This function may sleep so callers should not hold any locks
662 * where this would cause a problem.
663 */
664static int auditd_send_unicast_skb(struct sk_buff *skb)
665{
666 int rc;
667 u32 portid;
668 struct net *net;
669 struct sock *sk;
670 struct auditd_connection *ac;
671
672 /* NOTE: we can't call netlink_unicast while in the RCU section so
673 * take a reference to the network namespace and grab local
674 * copies of the namespace, the sock, and the portid; the
675 * namespace and sock aren't going to go away while we hold a
676 * reference and if the portid does become invalid after the RCU
677 * section netlink_unicast() should safely return an error */
678
679 rcu_read_lock();
680 ac = rcu_dereference(auditd_conn);
681 if (!ac) {
682 rcu_read_unlock();
683 kfree_skb(skb);
684 rc = -ECONNREFUSED;
685 goto err;
686 }
687 net = get_net(ac->net);
688 sk = audit_get_sk(net);
689 portid = ac->portid;
690 rcu_read_unlock();
691
692 rc = netlink_unicast(sk, skb, portid, 0);
693 put_net(net);
694 if (rc < 0)
695 goto err;
696
697 return rc;
698
699err:
700 if (ac && rc == -ECONNREFUSED)
701 auditd_reset(ac);
702 return rc;
703}
704
705/**
706 * kauditd_send_queue - Helper for kauditd_thread to flush skb queues
707 * @sk: the sending sock
708 * @portid: the netlink destination
709 * @queue: the skb queue to process
710 * @retry_limit: limit on number of netlink unicast failures
711 * @skb_hook: per-skb hook for additional processing
712 * @err_hook: hook called if the skb fails the netlink unicast send
713 *
714 * Description:
715 * Run through the given queue and attempt to send the audit records to auditd,
716 * returns zero on success, negative values on failure. It is up to the caller
717 * to ensure that the @sk is valid for the duration of this function.
718 *
719 */
720static int kauditd_send_queue(struct sock *sk, u32 portid,
721 struct sk_buff_head *queue,
722 unsigned int retry_limit,
723 void (*skb_hook)(struct sk_buff *skb),
724 void (*err_hook)(struct sk_buff *skb))
725{
726 int rc = 0;
727 struct sk_buff *skb;
728 static unsigned int failed = 0;
729
730 /* NOTE: kauditd_thread takes care of all our locking, we just use
731 * the netlink info passed to us (e.g. sk and portid) */
732
733 while ((skb = skb_dequeue(queue))) {
734 /* call the skb_hook for each skb we touch */
735 if (skb_hook)
736 (*skb_hook)(skb);
737
738 /* can we send to anyone via unicast? */
739 if (!sk) {
740 if (err_hook)
741 (*err_hook)(skb);
742 continue;
743 }
744
745 /* grab an extra skb reference in case of error */
746 skb_get(skb);
747 rc = netlink_unicast(sk, skb, portid, 0);
748 if (rc < 0) {
749 /* fatal failure for our queue flush attempt? */
750 if (++failed >= retry_limit ||
751 rc == -ECONNREFUSED || rc == -EPERM) {
752 /* yes - error processing for the queue */
753 sk = NULL;
754 if (err_hook)
755 (*err_hook)(skb);
756 if (!skb_hook)
757 goto out;
758 /* keep processing with the skb_hook */
759 continue;
760 } else
761 /* no - requeue to preserve ordering */
762 skb_queue_head(queue, skb);
763 } else {
764 /* it worked - drop the extra reference and continue */
765 consume_skb(skb);
766 failed = 0;
767 }
768 }
769
770out:
771 return (rc >= 0 ? 0 : rc);
772}
773
774/*
775 * kauditd_send_multicast_skb - Send a record to any multicast listeners
776 * @skb: audit record
777 *
778 * Description:
779 * Write a multicast message to anyone listening in the initial network
780 * namespace. This function doesn't consume an skb as might be expected since
781 * it has to copy it anyways.
782 */
783static void kauditd_send_multicast_skb(struct sk_buff *skb)
784{
785 struct sk_buff *copy;
786 struct sock *sock = audit_get_sk(&init_net);
787 struct nlmsghdr *nlh;
788
789 /* NOTE: we are not taking an additional reference for init_net since
790 * we don't have to worry about it going away */
791
792 if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
793 return;
794
795 /*
796 * The seemingly wasteful skb_copy() rather than bumping the refcount
797 * using skb_get() is necessary because non-standard mods are made to
798 * the skb by the original kaudit unicast socket send routine. The
799 * existing auditd daemon assumes this breakage. Fixing this would
800 * require co-ordinating a change in the established protocol between
801 * the kaudit kernel subsystem and the auditd userspace code. There is
802 * no reason for new multicast clients to continue with this
803 * non-compliance.
804 */
805 copy = skb_copy(skb, GFP_KERNEL);
806 if (!copy)
807 return;
808 nlh = nlmsg_hdr(copy);
809 nlh->nlmsg_len = skb->len;
810
811 nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL);
812}
813
814/**
815 * kauditd_thread - Worker thread to send audit records to userspace
816 * @dummy: unused
817 */
818static int kauditd_thread(void *dummy)
819{
820 int rc;
821 u32 portid = 0;
822 struct net *net = NULL;
823 struct sock *sk = NULL;
824 struct auditd_connection *ac;
825
826#define UNICAST_RETRIES 5
827
828 set_freezable();
829 while (!kthread_should_stop()) {
830 /* NOTE: see the lock comments in auditd_send_unicast_skb() */
831 rcu_read_lock();
832 ac = rcu_dereference(auditd_conn);
833 if (!ac) {
834 rcu_read_unlock();
835 goto main_queue;
836 }
837 net = get_net(ac->net);
838 sk = audit_get_sk(net);
839 portid = ac->portid;
840 rcu_read_unlock();
841
842 /* attempt to flush the hold queue */
843 rc = kauditd_send_queue(sk, portid,
844 &audit_hold_queue, UNICAST_RETRIES,
845 NULL, kauditd_rehold_skb);
846 if (ac && rc < 0) {
847 sk = NULL;
848 auditd_reset(ac);
849 goto main_queue;
850 }
851
852 /* attempt to flush the retry queue */
853 rc = kauditd_send_queue(sk, portid,
854 &audit_retry_queue, UNICAST_RETRIES,
855 NULL, kauditd_hold_skb);
856 if (ac && rc < 0) {
857 sk = NULL;
858 auditd_reset(ac);
859 goto main_queue;
860 }
861
862main_queue:
863 /* process the main queue - do the multicast send and attempt
864 * unicast, dump failed record sends to the retry queue; if
865 * sk == NULL due to previous failures we will just do the
866 * multicast send and move the record to the hold queue */
867 rc = kauditd_send_queue(sk, portid, &audit_queue, 1,
868 kauditd_send_multicast_skb,
869 (sk ?
870 kauditd_retry_skb : kauditd_hold_skb));
871 if (ac && rc < 0)
872 auditd_reset(ac);
873 sk = NULL;
874
875 /* drop our netns reference, no auditd sends past this line */
876 if (net) {
877 put_net(net);
878 net = NULL;
879 }
880
881 /* we have processed all the queues so wake everyone */
882 wake_up(&audit_backlog_wait);
883
884 /* NOTE: we want to wake up if there is anything on the queue,
885 * regardless of if an auditd is connected, as we need to
886 * do the multicast send and rotate records from the
887 * main queue to the retry/hold queues */
888 wait_event_freezable(kauditd_wait,
889 (skb_queue_len(&audit_queue) ? 1 : 0));
890 }
891
892 return 0;
893}
894
895int audit_send_list(void *_dest)
896{
897 struct audit_netlink_list *dest = _dest;
898 struct sk_buff *skb;
899 struct sock *sk = audit_get_sk(dest->net);
900
901 /* wait for parent to finish and send an ACK */
902 audit_ctl_lock();
903 audit_ctl_unlock();
904
905 while ((skb = __skb_dequeue(&dest->q)) != NULL)
906 netlink_unicast(sk, skb, dest->portid, 0);
907
908 put_net(dest->net);
909 kfree(dest);
910
911 return 0;
912}
913
914struct sk_buff *audit_make_reply(int seq, int type, int done,
915 int multi, const void *payload, int size)
916{
917 struct sk_buff *skb;
918 struct nlmsghdr *nlh;
919 void *data;
920 int flags = multi ? NLM_F_MULTI : 0;
921 int t = done ? NLMSG_DONE : type;
922
923 skb = nlmsg_new(size, GFP_KERNEL);
924 if (!skb)
925 return NULL;
926
927 nlh = nlmsg_put(skb, 0, seq, t, size, flags);
928 if (!nlh)
929 goto out_kfree_skb;
930 data = nlmsg_data(nlh);
931 memcpy(data, payload, size);
932 return skb;
933
934out_kfree_skb:
935 kfree_skb(skb);
936 return NULL;
937}
938
939static int audit_send_reply_thread(void *arg)
940{
941 struct audit_reply *reply = (struct audit_reply *)arg;
942 struct sock *sk = audit_get_sk(reply->net);
943
944 audit_ctl_lock();
945 audit_ctl_unlock();
946
947 /* Ignore failure. It'll only happen if the sender goes away,
948 because our timeout is set to infinite. */
949 netlink_unicast(sk, reply->skb, reply->portid, 0);
950 put_net(reply->net);
951 kfree(reply);
952 return 0;
953}
954
955/**
956 * audit_send_reply - send an audit reply message via netlink
957 * @request_skb: skb of request we are replying to (used to target the reply)
958 * @seq: sequence number
959 * @type: audit message type
960 * @done: done (last) flag
961 * @multi: multi-part message flag
962 * @payload: payload data
963 * @size: payload size
964 *
965 * Allocates an skb, builds the netlink message, and sends it to the port id.
966 * No failure notifications.
967 */
968static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
969 int multi, const void *payload, int size)
970{
971 struct net *net = sock_net(NETLINK_CB(request_skb).sk);
972 struct sk_buff *skb;
973 struct task_struct *tsk;
974 struct audit_reply *reply = kmalloc(sizeof(struct audit_reply),
975 GFP_KERNEL);
976
977 if (!reply)
978 return;
979
980 skb = audit_make_reply(seq, type, done, multi, payload, size);
981 if (!skb)
982 goto out;
983
984 reply->net = get_net(net);
985 reply->portid = NETLINK_CB(request_skb).portid;
986 reply->skb = skb;
987
988 tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
989 if (!IS_ERR(tsk))
990 return;
991 kfree_skb(skb);
992out:
993 kfree(reply);
994}
995
996/*
997 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
998 * control messages.
999 */
1000static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
1001{
1002 int err = 0;
1003
1004 /* Only support initial user namespace for now. */
1005 /*
1006 * We return ECONNREFUSED because it tricks userspace into thinking
1007 * that audit was not configured into the kernel. Lots of users
1008 * configure their PAM stack (because that's what the distro does)
1009 * to reject login if unable to send messages to audit. If we return
1010 * ECONNREFUSED the PAM stack thinks the kernel does not have audit
1011 * configured in and will let login proceed. If we return EPERM
1012 * userspace will reject all logins. This should be removed when we
1013 * support non init namespaces!!
1014 */
1015 if (current_user_ns() != &init_user_ns)
1016 return -ECONNREFUSED;
1017
1018 switch (msg_type) {
1019 case AUDIT_LIST:
1020 case AUDIT_ADD:
1021 case AUDIT_DEL:
1022 return -EOPNOTSUPP;
1023 case AUDIT_GET:
1024 case AUDIT_SET:
1025 case AUDIT_GET_FEATURE:
1026 case AUDIT_SET_FEATURE:
1027 case AUDIT_LIST_RULES:
1028 case AUDIT_ADD_RULE:
1029 case AUDIT_DEL_RULE:
1030 case AUDIT_SIGNAL_INFO:
1031 case AUDIT_TTY_GET:
1032 case AUDIT_TTY_SET:
1033 case AUDIT_TRIM:
1034 case AUDIT_MAKE_EQUIV:
1035 /* Only support auditd and auditctl in initial pid namespace
1036 * for now. */
1037 if (task_active_pid_ns(current) != &init_pid_ns)
1038 return -EPERM;
1039
1040 if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
1041 err = -EPERM;
1042 break;
1043 case AUDIT_USER:
1044 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1045 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1046 if (!netlink_capable(skb, CAP_AUDIT_WRITE))
1047 err = -EPERM;
1048 break;
1049 default: /* bad msg */
1050 err = -EINVAL;
1051 }
1052
1053 return err;
1054}
1055
1056static void audit_log_common_recv_msg(struct audit_context *context,
1057 struct audit_buffer **ab, u16 msg_type)
1058{
1059 uid_t uid = from_kuid(&init_user_ns, current_uid());
1060 pid_t pid = task_tgid_nr(current);
1061
1062 if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
1063 *ab = NULL;
1064 return;
1065 }
1066
1067 *ab = audit_log_start(context, GFP_KERNEL, msg_type);
1068 if (unlikely(!*ab))
1069 return;
1070 audit_log_format(*ab, "pid=%d uid=%u ", pid, uid);
1071 audit_log_session_info(*ab);
1072 audit_log_task_context(*ab);
1073}
1074
1075static inline void audit_log_user_recv_msg(struct audit_buffer **ab,
1076 u16 msg_type)
1077{
1078 audit_log_common_recv_msg(NULL, ab, msg_type);
1079}
1080
1081int is_audit_feature_set(int i)
1082{
1083 return af.features & AUDIT_FEATURE_TO_MASK(i);
1084}
1085
1086
1087static int audit_get_feature(struct sk_buff *skb)
1088{
1089 u32 seq;
1090
1091 seq = nlmsg_hdr(skb)->nlmsg_seq;
1092
1093 audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af));
1094
1095 return 0;
1096}
1097
1098static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
1099 u32 old_lock, u32 new_lock, int res)
1100{
1101 struct audit_buffer *ab;
1102
1103 if (audit_enabled == AUDIT_OFF)
1104 return;
1105
1106 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_FEATURE_CHANGE);
1107 if (!ab)
1108 return;
1109 audit_log_task_info(ab);
1110 audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
1111 audit_feature_names[which], !!old_feature, !!new_feature,
1112 !!old_lock, !!new_lock, res);
1113 audit_log_end(ab);
1114}
1115
1116static int audit_set_feature(struct sk_buff *skb)
1117{
1118 struct audit_features *uaf;
1119 int i;
1120
1121 BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
1122 uaf = nlmsg_data(nlmsg_hdr(skb));
1123
1124 /* if there is ever a version 2 we should handle that here */
1125
1126 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1127 u32 feature = AUDIT_FEATURE_TO_MASK(i);
1128 u32 old_feature, new_feature, old_lock, new_lock;
1129
1130 /* if we are not changing this feature, move along */
1131 if (!(feature & uaf->mask))
1132 continue;
1133
1134 old_feature = af.features & feature;
1135 new_feature = uaf->features & feature;
1136 new_lock = (uaf->lock | af.lock) & feature;
1137 old_lock = af.lock & feature;
1138
1139 /* are we changing a locked feature? */
1140 if (old_lock && (new_feature != old_feature)) {
1141 audit_log_feature_change(i, old_feature, new_feature,
1142 old_lock, new_lock, 0);
1143 return -EPERM;
1144 }
1145 }
1146 /* nothing invalid, do the changes */
1147 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1148 u32 feature = AUDIT_FEATURE_TO_MASK(i);
1149 u32 old_feature, new_feature, old_lock, new_lock;
1150
1151 /* if we are not changing this feature, move along */
1152 if (!(feature & uaf->mask))
1153 continue;
1154
1155 old_feature = af.features & feature;
1156 new_feature = uaf->features & feature;
1157 old_lock = af.lock & feature;
1158 new_lock = (uaf->lock | af.lock) & feature;
1159
1160 if (new_feature != old_feature)
1161 audit_log_feature_change(i, old_feature, new_feature,
1162 old_lock, new_lock, 1);
1163
1164 if (new_feature)
1165 af.features |= feature;
1166 else
1167 af.features &= ~feature;
1168 af.lock |= new_lock;
1169 }
1170
1171 return 0;
1172}
1173
1174static int audit_replace(struct pid *pid)
1175{
1176 pid_t pvnr;
1177 struct sk_buff *skb;
1178
1179 pvnr = pid_vnr(pid);
1180 skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pvnr, sizeof(pvnr));
1181 if (!skb)
1182 return -ENOMEM;
1183 return auditd_send_unicast_skb(skb);
1184}
1185
1186static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
1187{
1188 u32 seq;
1189 void *data;
1190 int err;
1191 struct audit_buffer *ab;
1192 u16 msg_type = nlh->nlmsg_type;
1193 struct audit_sig_info *sig_data;
1194 char *ctx = NULL;
1195 u32 len;
1196
1197 err = audit_netlink_ok(skb, msg_type);
1198 if (err)
1199 return err;
1200
1201 seq = nlh->nlmsg_seq;
1202 data = nlmsg_data(nlh);
1203
1204 switch (msg_type) {
1205 case AUDIT_GET: {
1206 struct audit_status s;
1207 memset(&s, 0, sizeof(s));
1208 s.enabled = audit_enabled;
1209 s.failure = audit_failure;
1210 /* NOTE: use pid_vnr() so the PID is relative to the current
1211 * namespace */
1212 s.pid = auditd_pid_vnr();
1213 s.rate_limit = audit_rate_limit;
1214 s.backlog_limit = audit_backlog_limit;
1215 s.lost = atomic_read(&audit_lost);
1216 s.backlog = skb_queue_len(&audit_queue);
1217 s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL;
1218 s.backlog_wait_time = audit_backlog_wait_time;
1219 audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
1220 break;
1221 }
1222 case AUDIT_SET: {
1223 struct audit_status s;
1224 memset(&s, 0, sizeof(s));
1225 /* guard against past and future API changes */
1226 memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
1227 if (s.mask & AUDIT_STATUS_ENABLED) {
1228 err = audit_set_enabled(s.enabled);
1229 if (err < 0)
1230 return err;
1231 }
1232 if (s.mask & AUDIT_STATUS_FAILURE) {
1233 err = audit_set_failure(s.failure);
1234 if (err < 0)
1235 return err;
1236 }
1237 if (s.mask & AUDIT_STATUS_PID) {
1238 /* NOTE: we are using the vnr PID functions below
1239 * because the s.pid value is relative to the
1240 * namespace of the caller; at present this
1241 * doesn't matter much since you can really only
1242 * run auditd from the initial pid namespace, but
1243 * something to keep in mind if this changes */
1244 pid_t new_pid = s.pid;
1245 pid_t auditd_pid;
1246 struct pid *req_pid = task_tgid(current);
1247
1248 /* Sanity check - PID values must match. Setting
1249 * pid to 0 is how auditd ends auditing. */
1250 if (new_pid && (new_pid != pid_vnr(req_pid)))
1251 return -EINVAL;
1252
1253 /* test the auditd connection */
1254 audit_replace(req_pid);
1255
1256 auditd_pid = auditd_pid_vnr();
1257 if (auditd_pid) {
1258 /* replacing a healthy auditd is not allowed */
1259 if (new_pid) {
1260 audit_log_config_change("audit_pid",
1261 new_pid, auditd_pid, 0);
1262 return -EEXIST;
1263 }
1264 /* only current auditd can unregister itself */
1265 if (pid_vnr(req_pid) != auditd_pid) {
1266 audit_log_config_change("audit_pid",
1267 new_pid, auditd_pid, 0);
1268 return -EACCES;
1269 }
1270 }
1271
1272 if (new_pid) {
1273 /* register a new auditd connection */
1274 err = auditd_set(req_pid,
1275 NETLINK_CB(skb).portid,
1276 sock_net(NETLINK_CB(skb).sk));
1277 if (audit_enabled != AUDIT_OFF)
1278 audit_log_config_change("audit_pid",
1279 new_pid,
1280 auditd_pid,
1281 err ? 0 : 1);
1282 if (err)
1283 return err;
1284
1285 /* try to process any backlog */
1286 wake_up_interruptible(&kauditd_wait);
1287 } else {
1288 if (audit_enabled != AUDIT_OFF)
1289 audit_log_config_change("audit_pid",
1290 new_pid,
1291 auditd_pid, 1);
1292
1293 /* unregister the auditd connection */
1294 auditd_reset(NULL);
1295 }
1296 }
1297 if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
1298 err = audit_set_rate_limit(s.rate_limit);
1299 if (err < 0)
1300 return err;
1301 }
1302 if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
1303 err = audit_set_backlog_limit(s.backlog_limit);
1304 if (err < 0)
1305 return err;
1306 }
1307 if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
1308 if (sizeof(s) > (size_t)nlh->nlmsg_len)
1309 return -EINVAL;
1310 if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
1311 return -EINVAL;
1312 err = audit_set_backlog_wait_time(s.backlog_wait_time);
1313 if (err < 0)
1314 return err;
1315 }
1316 if (s.mask == AUDIT_STATUS_LOST) {
1317 u32 lost = atomic_xchg(&audit_lost, 0);
1318
1319 audit_log_config_change("lost", 0, lost, 1);
1320 return lost;
1321 }
1322 break;
1323 }
1324 case AUDIT_GET_FEATURE:
1325 err = audit_get_feature(skb);
1326 if (err)
1327 return err;
1328 break;
1329 case AUDIT_SET_FEATURE:
1330 err = audit_set_feature(skb);
1331 if (err)
1332 return err;
1333 break;
1334 case AUDIT_USER:
1335 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1336 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1337 if (!audit_enabled && msg_type != AUDIT_USER_AVC)
1338 return 0;
1339
1340 err = audit_filter(msg_type, AUDIT_FILTER_USER);
1341 if (err == 1) { /* match or error */
1342 err = 0;
1343 if (msg_type == AUDIT_USER_TTY) {
1344 err = tty_audit_push();
1345 if (err)
1346 break;
1347 }
1348 audit_log_user_recv_msg(&ab, msg_type);
1349 if (msg_type != AUDIT_USER_TTY)
1350 audit_log_format(ab, " msg='%.*s'",
1351 AUDIT_MESSAGE_TEXT_MAX,
1352 (char *)data);
1353 else {
1354 int size;
1355
1356 audit_log_format(ab, " data=");
1357 size = nlmsg_len(nlh);
1358 if (size > 0 &&
1359 ((unsigned char *)data)[size - 1] == '\0')
1360 size--;
1361 audit_log_n_untrustedstring(ab, data, size);
1362 }
1363 audit_log_end(ab);
1364 }
1365 break;
1366 case AUDIT_ADD_RULE:
1367 case AUDIT_DEL_RULE:
1368 if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
1369 return -EINVAL;
1370 if (audit_enabled == AUDIT_LOCKED) {
1371 audit_log_common_recv_msg(audit_context(), &ab,
1372 AUDIT_CONFIG_CHANGE);
1373 audit_log_format(ab, " op=%s audit_enabled=%d res=0",
1374 msg_type == AUDIT_ADD_RULE ?
1375 "add_rule" : "remove_rule",
1376 audit_enabled);
1377 audit_log_end(ab);
1378 return -EPERM;
1379 }
1380 err = audit_rule_change(msg_type, seq, data, nlmsg_len(nlh));
1381 break;
1382 case AUDIT_LIST_RULES:
1383 err = audit_list_rules_send(skb, seq);
1384 break;
1385 case AUDIT_TRIM:
1386 audit_trim_trees();
1387 audit_log_common_recv_msg(audit_context(), &ab,
1388 AUDIT_CONFIG_CHANGE);
1389 audit_log_format(ab, " op=trim res=1");
1390 audit_log_end(ab);
1391 break;
1392 case AUDIT_MAKE_EQUIV: {
1393 void *bufp = data;
1394 u32 sizes[2];
1395 size_t msglen = nlmsg_len(nlh);
1396 char *old, *new;
1397
1398 err = -EINVAL;
1399 if (msglen < 2 * sizeof(u32))
1400 break;
1401 memcpy(sizes, bufp, 2 * sizeof(u32));
1402 bufp += 2 * sizeof(u32);
1403 msglen -= 2 * sizeof(u32);
1404 old = audit_unpack_string(&bufp, &msglen, sizes[0]);
1405 if (IS_ERR(old)) {
1406 err = PTR_ERR(old);
1407 break;
1408 }
1409 new = audit_unpack_string(&bufp, &msglen, sizes[1]);
1410 if (IS_ERR(new)) {
1411 err = PTR_ERR(new);
1412 kfree(old);
1413 break;
1414 }
1415 /* OK, here comes... */
1416 err = audit_tag_tree(old, new);
1417
1418 audit_log_common_recv_msg(audit_context(), &ab,
1419 AUDIT_CONFIG_CHANGE);
1420 audit_log_format(ab, " op=make_equiv old=");
1421 audit_log_untrustedstring(ab, old);
1422 audit_log_format(ab, " new=");
1423 audit_log_untrustedstring(ab, new);
1424 audit_log_format(ab, " res=%d", !err);
1425 audit_log_end(ab);
1426 kfree(old);
1427 kfree(new);
1428 break;
1429 }
1430 case AUDIT_SIGNAL_INFO:
1431 len = 0;
1432 if (audit_sig_sid) {
1433 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
1434 if (err)
1435 return err;
1436 }
1437 sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
1438 if (!sig_data) {
1439 if (audit_sig_sid)
1440 security_release_secctx(ctx, len);
1441 return -ENOMEM;
1442 }
1443 sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
1444 sig_data->pid = audit_sig_pid;
1445 if (audit_sig_sid) {
1446 memcpy(sig_data->ctx, ctx, len);
1447 security_release_secctx(ctx, len);
1448 }
1449 audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
1450 sig_data, sizeof(*sig_data) + len);
1451 kfree(sig_data);
1452 break;
1453 case AUDIT_TTY_GET: {
1454 struct audit_tty_status s;
1455 unsigned int t;
1456
1457 t = READ_ONCE(current->signal->audit_tty);
1458 s.enabled = t & AUDIT_TTY_ENABLE;
1459 s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1460
1461 audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
1462 break;
1463 }
1464 case AUDIT_TTY_SET: {
1465 struct audit_tty_status s, old;
1466 struct audit_buffer *ab;
1467 unsigned int t;
1468
1469 memset(&s, 0, sizeof(s));
1470 /* guard against past and future API changes */
1471 memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
1472 /* check if new data is valid */
1473 if ((s.enabled != 0 && s.enabled != 1) ||
1474 (s.log_passwd != 0 && s.log_passwd != 1))
1475 err = -EINVAL;
1476
1477 if (err)
1478 t = READ_ONCE(current->signal->audit_tty);
1479 else {
1480 t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD);
1481 t = xchg(&current->signal->audit_tty, t);
1482 }
1483 old.enabled = t & AUDIT_TTY_ENABLE;
1484 old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1485
1486 audit_log_common_recv_msg(audit_context(), &ab,
1487 AUDIT_CONFIG_CHANGE);
1488 audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
1489 " old-log_passwd=%d new-log_passwd=%d res=%d",
1490 old.enabled, s.enabled, old.log_passwd,
1491 s.log_passwd, !err);
1492 audit_log_end(ab);
1493 break;
1494 }
1495 default:
1496 err = -EINVAL;
1497 break;
1498 }
1499
1500 return err < 0 ? err : 0;
1501}
1502
1503/**
1504 * audit_receive - receive messages from a netlink control socket
1505 * @skb: the message buffer
1506 *
1507 * Parse the provided skb and deal with any messages that may be present,
1508 * malformed skbs are discarded.
1509 */
1510static void audit_receive(struct sk_buff *skb)
1511{
1512 struct nlmsghdr *nlh;
1513 /*
1514 * len MUST be signed for nlmsg_next to be able to dec it below 0
1515 * if the nlmsg_len was not aligned
1516 */
1517 int len;
1518 int err;
1519
1520 nlh = nlmsg_hdr(skb);
1521 len = skb->len;
1522
1523 audit_ctl_lock();
1524 while (nlmsg_ok(nlh, len)) {
1525 err = audit_receive_msg(skb, nlh);
1526 /* if err or if this message says it wants a response */
1527 if (err || (nlh->nlmsg_flags & NLM_F_ACK))
1528 netlink_ack(skb, nlh, err, NULL);
1529
1530 nlh = nlmsg_next(nlh, &len);
1531 }
1532 audit_ctl_unlock();
1533}
1534
1535/* Run custom bind function on netlink socket group connect or bind requests. */
1536static int audit_bind(struct net *net, int group)
1537{
1538 if (!capable(CAP_AUDIT_READ))
1539 return -EPERM;
1540
1541 return 0;
1542}
1543
1544static int __net_init audit_net_init(struct net *net)
1545{
1546 struct netlink_kernel_cfg cfg = {
1547 .input = audit_receive,
1548 .bind = audit_bind,
1549 .flags = NL_CFG_F_NONROOT_RECV,
1550 .groups = AUDIT_NLGRP_MAX,
1551 };
1552
1553 struct audit_net *aunet = net_generic(net, audit_net_id);
1554
1555 aunet->sk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
1556 if (aunet->sk == NULL) {
1557 audit_panic("cannot initialize netlink socket in namespace");
1558 return -ENOMEM;
1559 }
1560 aunet->sk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
1561
1562 return 0;
1563}
1564
1565static void __net_exit audit_net_exit(struct net *net)
1566{
1567 struct audit_net *aunet = net_generic(net, audit_net_id);
1568
1569 /* NOTE: you would think that we would want to check the auditd
1570 * connection and potentially reset it here if it lives in this
1571 * namespace, but since the auditd connection tracking struct holds a
1572 * reference to this namespace (see auditd_set()) we are only ever
1573 * going to get here after that connection has been released */
1574
1575 netlink_kernel_release(aunet->sk);
1576}
1577
1578static struct pernet_operations audit_net_ops __net_initdata = {
1579 .init = audit_net_init,
1580 .exit = audit_net_exit,
1581 .id = &audit_net_id,
1582 .size = sizeof(struct audit_net),
1583};
1584
1585/* Initialize audit support at boot time. */
1586static int __init audit_init(void)
1587{
1588 int i;
1589
1590 if (audit_initialized == AUDIT_DISABLED)
1591 return 0;
1592
1593 audit_buffer_cache = kmem_cache_create("audit_buffer",
1594 sizeof(struct audit_buffer),
1595 0, SLAB_PANIC, NULL);
1596
1597 skb_queue_head_init(&audit_queue);
1598 skb_queue_head_init(&audit_retry_queue);
1599 skb_queue_head_init(&audit_hold_queue);
1600
1601 for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
1602 INIT_LIST_HEAD(&audit_inode_hash[i]);
1603
1604 mutex_init(&audit_cmd_mutex.lock);
1605 audit_cmd_mutex.owner = NULL;
1606
1607 pr_info("initializing netlink subsys (%s)\n",
1608 audit_default ? "enabled" : "disabled");
1609 register_pernet_subsys(&audit_net_ops);
1610
1611 audit_initialized = AUDIT_INITIALIZED;
1612
1613 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
1614 if (IS_ERR(kauditd_task)) {
1615 int err = PTR_ERR(kauditd_task);
1616 panic("audit: failed to start the kauditd thread (%d)\n", err);
1617 }
1618
1619 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL,
1620 "state=initialized audit_enabled=%u res=1",
1621 audit_enabled);
1622
1623 return 0;
1624}
1625postcore_initcall(audit_init);
1626
1627/*
1628 * Process kernel command-line parameter at boot time.
1629 * audit={0|off} or audit={1|on}.
1630 */
1631static int __init audit_enable(char *str)
1632{
1633 if (!strcasecmp(str, "off") || !strcmp(str, "0"))
1634 audit_default = AUDIT_OFF;
1635 else if (!strcasecmp(str, "on") || !strcmp(str, "1"))
1636 audit_default = AUDIT_ON;
1637 else {
1638 pr_err("audit: invalid 'audit' parameter value (%s)\n", str);
1639 audit_default = AUDIT_ON;
1640 }
1641
1642 if (audit_default == AUDIT_OFF)
1643 audit_initialized = AUDIT_DISABLED;
1644 if (audit_set_enabled(audit_default))
1645 pr_err("audit: error setting audit state (%d)\n",
1646 audit_default);
1647
1648 pr_info("%s\n", audit_default ?
1649 "enabled (after initialization)" : "disabled (until reboot)");
1650
1651 return 1;
1652}
1653__setup("audit=", audit_enable);
1654
1655/* Process kernel command-line parameter at boot time.
1656 * audit_backlog_limit=<n> */
1657static int __init audit_backlog_limit_set(char *str)
1658{
1659 u32 audit_backlog_limit_arg;
1660
1661 pr_info("audit_backlog_limit: ");
1662 if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
1663 pr_cont("using default of %u, unable to parse %s\n",
1664 audit_backlog_limit, str);
1665 return 1;
1666 }
1667
1668 audit_backlog_limit = audit_backlog_limit_arg;
1669 pr_cont("%d\n", audit_backlog_limit);
1670
1671 return 1;
1672}
1673__setup("audit_backlog_limit=", audit_backlog_limit_set);
1674
1675static void audit_buffer_free(struct audit_buffer *ab)
1676{
1677 if (!ab)
1678 return;
1679
1680 kfree_skb(ab->skb);
1681 kmem_cache_free(audit_buffer_cache, ab);
1682}
1683
1684static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx,
1685 gfp_t gfp_mask, int type)
1686{
1687 struct audit_buffer *ab;
1688
1689 ab = kmem_cache_alloc(audit_buffer_cache, gfp_mask);
1690 if (!ab)
1691 return NULL;
1692
1693 ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
1694 if (!ab->skb)
1695 goto err;
1696 if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0))
1697 goto err;
1698
1699 ab->ctx = ctx;
1700 ab->gfp_mask = gfp_mask;
1701
1702 return ab;
1703
1704err:
1705 audit_buffer_free(ab);
1706 return NULL;
1707}
1708
1709/**
1710 * audit_serial - compute a serial number for the audit record
1711 *
1712 * Compute a serial number for the audit record. Audit records are
1713 * written to user-space as soon as they are generated, so a complete
1714 * audit record may be written in several pieces. The timestamp of the
1715 * record and this serial number are used by the user-space tools to
1716 * determine which pieces belong to the same audit record. The
1717 * (timestamp,serial) tuple is unique for each syscall and is live from
1718 * syscall entry to syscall exit.
1719 *
1720 * NOTE: Another possibility is to store the formatted records off the
1721 * audit context (for those records that have a context), and emit them
1722 * all at syscall exit. However, this could delay the reporting of
1723 * significant errors until syscall exit (or never, if the system
1724 * halts).
1725 */
1726unsigned int audit_serial(void)
1727{
1728 static atomic_t serial = ATOMIC_INIT(0);
1729
1730 return atomic_add_return(1, &serial);
1731}
1732
1733static inline void audit_get_stamp(struct audit_context *ctx,
1734 struct timespec64 *t, unsigned int *serial)
1735{
1736 if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
1737 ktime_get_coarse_real_ts64(t);
1738 *serial = audit_serial();
1739 }
1740}
1741
1742/**
1743 * audit_log_start - obtain an audit buffer
1744 * @ctx: audit_context (may be NULL)
1745 * @gfp_mask: type of allocation
1746 * @type: audit message type
1747 *
1748 * Returns audit_buffer pointer on success or NULL on error.
1749 *
1750 * Obtain an audit buffer. This routine does locking to obtain the
1751 * audit buffer, but then no locking is required for calls to
1752 * audit_log_*format. If the task (ctx) is a task that is currently in a
1753 * syscall, then the syscall is marked as auditable and an audit record
1754 * will be written at syscall exit. If there is no associated task, then
1755 * task context (ctx) should be NULL.
1756 */
1757struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1758 int type)
1759{
1760 struct audit_buffer *ab;
1761 struct timespec64 t;
1762 unsigned int uninitialized_var(serial);
1763
1764 if (audit_initialized != AUDIT_INITIALIZED)
1765 return NULL;
1766
1767 if (unlikely(!audit_filter(type, AUDIT_FILTER_EXCLUDE)))
1768 return NULL;
1769
1770 /* NOTE: don't ever fail/sleep on these two conditions:
1771 * 1. auditd generated record - since we need auditd to drain the
1772 * queue; also, when we are checking for auditd, compare PIDs using
1773 * task_tgid_vnr() since auditd_pid is set in audit_receive_msg()
1774 * using a PID anchored in the caller's namespace
1775 * 2. generator holding the audit_cmd_mutex - we don't want to block
1776 * while holding the mutex */
1777 if (!(auditd_test_task(current) || audit_ctl_owner_current())) {
1778 long stime = audit_backlog_wait_time;
1779
1780 while (audit_backlog_limit &&
1781 (skb_queue_len(&audit_queue) > audit_backlog_limit)) {
1782 /* wake kauditd to try and flush the queue */
1783 wake_up_interruptible(&kauditd_wait);
1784
1785 /* sleep if we are allowed and we haven't exhausted our
1786 * backlog wait limit */
1787 if (gfpflags_allow_blocking(gfp_mask) && (stime > 0)) {
1788 DECLARE_WAITQUEUE(wait, current);
1789
1790 add_wait_queue_exclusive(&audit_backlog_wait,
1791 &wait);
1792 set_current_state(TASK_UNINTERRUPTIBLE);
1793 stime = schedule_timeout(stime);
1794 remove_wait_queue(&audit_backlog_wait, &wait);
1795 } else {
1796 if (audit_rate_check() && printk_ratelimit())
1797 pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
1798 skb_queue_len(&audit_queue),
1799 audit_backlog_limit);
1800 audit_log_lost("backlog limit exceeded");
1801 return NULL;
1802 }
1803 }
1804 }
1805
1806 ab = audit_buffer_alloc(ctx, gfp_mask, type);
1807 if (!ab) {
1808 audit_log_lost("out of memory in audit_log_start");
1809 return NULL;
1810 }
1811
1812 audit_get_stamp(ab->ctx, &t, &serial);
1813 audit_log_format(ab, "audit(%llu.%03lu:%u): ",
1814 (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
1815
1816 return ab;
1817}
1818
1819/**
1820 * audit_expand - expand skb in the audit buffer
1821 * @ab: audit_buffer
1822 * @extra: space to add at tail of the skb
1823 *
1824 * Returns 0 (no space) on failed expansion, or available space if
1825 * successful.
1826 */
1827static inline int audit_expand(struct audit_buffer *ab, int extra)
1828{
1829 struct sk_buff *skb = ab->skb;
1830 int oldtail = skb_tailroom(skb);
1831 int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1832 int newtail = skb_tailroom(skb);
1833
1834 if (ret < 0) {
1835 audit_log_lost("out of memory in audit_expand");
1836 return 0;
1837 }
1838
1839 skb->truesize += newtail - oldtail;
1840 return newtail;
1841}
1842
1843/*
1844 * Format an audit message into the audit buffer. If there isn't enough
1845 * room in the audit buffer, more room will be allocated and vsnprint
1846 * will be called a second time. Currently, we assume that a printk
1847 * can't format message larger than 1024 bytes, so we don't either.
1848 */
1849static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1850 va_list args)
1851{
1852 int len, avail;
1853 struct sk_buff *skb;
1854 va_list args2;
1855
1856 if (!ab)
1857 return;
1858
1859 BUG_ON(!ab->skb);
1860 skb = ab->skb;
1861 avail = skb_tailroom(skb);
1862 if (avail == 0) {
1863 avail = audit_expand(ab, AUDIT_BUFSIZ);
1864 if (!avail)
1865 goto out;
1866 }
1867 va_copy(args2, args);
1868 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1869 if (len >= avail) {
1870 /* The printk buffer is 1024 bytes long, so if we get
1871 * here and AUDIT_BUFSIZ is at least 1024, then we can
1872 * log everything that printk could have logged. */
1873 avail = audit_expand(ab,
1874 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1875 if (!avail)
1876 goto out_va_end;
1877 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1878 }
1879 if (len > 0)
1880 skb_put(skb, len);
1881out_va_end:
1882 va_end(args2);
1883out:
1884 return;
1885}
1886
1887/**
1888 * audit_log_format - format a message into the audit buffer.
1889 * @ab: audit_buffer
1890 * @fmt: format string
1891 * @...: optional parameters matching @fmt string
1892 *
1893 * All the work is done in audit_log_vformat.
1894 */
1895void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1896{
1897 va_list args;
1898
1899 if (!ab)
1900 return;
1901 va_start(args, fmt);
1902 audit_log_vformat(ab, fmt, args);
1903 va_end(args);
1904}
1905
1906/**
1907 * audit_log_n_hex - convert a buffer to hex and append it to the audit skb
1908 * @ab: the audit_buffer
1909 * @buf: buffer to convert to hex
1910 * @len: length of @buf to be converted
1911 *
1912 * No return value; failure to expand is silently ignored.
1913 *
1914 * This function will take the passed buf and convert it into a string of
1915 * ascii hex digits. The new string is placed onto the skb.
1916 */
1917void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
1918 size_t len)
1919{
1920 int i, avail, new_len;
1921 unsigned char *ptr;
1922 struct sk_buff *skb;
1923
1924 if (!ab)
1925 return;
1926
1927 BUG_ON(!ab->skb);
1928 skb = ab->skb;
1929 avail = skb_tailroom(skb);
1930 new_len = len<<1;
1931 if (new_len >= avail) {
1932 /* Round the buffer request up to the next multiple */
1933 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1934 avail = audit_expand(ab, new_len);
1935 if (!avail)
1936 return;
1937 }
1938
1939 ptr = skb_tail_pointer(skb);
1940 for (i = 0; i < len; i++)
1941 ptr = hex_byte_pack_upper(ptr, buf[i]);
1942 *ptr = 0;
1943 skb_put(skb, len << 1); /* new string is twice the old string */
1944}
1945
1946/*
1947 * Format a string of no more than slen characters into the audit buffer,
1948 * enclosed in quote marks.
1949 */
1950void audit_log_n_string(struct audit_buffer *ab, const char *string,
1951 size_t slen)
1952{
1953 int avail, new_len;
1954 unsigned char *ptr;
1955 struct sk_buff *skb;
1956
1957 if (!ab)
1958 return;
1959
1960 BUG_ON(!ab->skb);
1961 skb = ab->skb;
1962 avail = skb_tailroom(skb);
1963 new_len = slen + 3; /* enclosing quotes + null terminator */
1964 if (new_len > avail) {
1965 avail = audit_expand(ab, new_len);
1966 if (!avail)
1967 return;
1968 }
1969 ptr = skb_tail_pointer(skb);
1970 *ptr++ = '"';
1971 memcpy(ptr, string, slen);
1972 ptr += slen;
1973 *ptr++ = '"';
1974 *ptr = 0;
1975 skb_put(skb, slen + 2); /* don't include null terminator */
1976}
1977
1978/**
1979 * audit_string_contains_control - does a string need to be logged in hex
1980 * @string: string to be checked
1981 * @len: max length of the string to check
1982 */
1983bool audit_string_contains_control(const char *string, size_t len)
1984{
1985 const unsigned char *p;
1986 for (p = string; p < (const unsigned char *)string + len; p++) {
1987 if (*p == '"' || *p < 0x21 || *p > 0x7e)
1988 return true;
1989 }
1990 return false;
1991}
1992
1993/**
1994 * audit_log_n_untrustedstring - log a string that may contain random characters
1995 * @ab: audit_buffer
1996 * @len: length of string (not including trailing null)
1997 * @string: string to be logged
1998 *
1999 * This code will escape a string that is passed to it if the string
2000 * contains a control character, unprintable character, double quote mark,
2001 * or a space. Unescaped strings will start and end with a double quote mark.
2002 * Strings that are escaped are printed in hex (2 digits per char).
2003 *
2004 * The caller specifies the number of characters in the string to log, which may
2005 * or may not be the entire string.
2006 */
2007void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
2008 size_t len)
2009{
2010 if (audit_string_contains_control(string, len))
2011 audit_log_n_hex(ab, string, len);
2012 else
2013 audit_log_n_string(ab, string, len);
2014}
2015
2016/**
2017 * audit_log_untrustedstring - log a string that may contain random characters
2018 * @ab: audit_buffer
2019 * @string: string to be logged
2020 *
2021 * Same as audit_log_n_untrustedstring(), except that strlen is used to
2022 * determine string length.
2023 */
2024void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
2025{
2026 audit_log_n_untrustedstring(ab, string, strlen(string));
2027}
2028
2029/* This is a helper-function to print the escaped d_path */
2030void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
2031 const struct path *path)
2032{
2033 char *p, *pathname;
2034
2035 if (prefix)
2036 audit_log_format(ab, "%s", prefix);
2037
2038 /* We will allow 11 spaces for ' (deleted)' to be appended */
2039 pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
2040 if (!pathname) {
2041 audit_log_string(ab, "<no_memory>");
2042 return;
2043 }
2044 p = d_path(path, pathname, PATH_MAX+11);
2045 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
2046 /* FIXME: can we save some information here? */
2047 audit_log_string(ab, "<too_long>");
2048 } else
2049 audit_log_untrustedstring(ab, p);
2050 kfree(pathname);
2051}
2052
2053void audit_log_session_info(struct audit_buffer *ab)
2054{
2055 unsigned int sessionid = audit_get_sessionid(current);
2056 uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
2057
2058 audit_log_format(ab, "auid=%u ses=%u", auid, sessionid);
2059}
2060
2061void audit_log_key(struct audit_buffer *ab, char *key)
2062{
2063 audit_log_format(ab, " key=");
2064 if (key)
2065 audit_log_untrustedstring(ab, key);
2066 else
2067 audit_log_format(ab, "(null)");
2068}
2069
2070int audit_log_task_context(struct audit_buffer *ab)
2071{
2072 char *ctx = NULL;
2073 unsigned len;
2074 int error;
2075 u32 sid;
2076
2077 security_task_getsecid(current, &sid);
2078 if (!sid)
2079 return 0;
2080
2081 error = security_secid_to_secctx(sid, &ctx, &len);
2082 if (error) {
2083 if (error != -EINVAL)
2084 goto error_path;
2085 return 0;
2086 }
2087
2088 audit_log_format(ab, " subj=%s", ctx);
2089 security_release_secctx(ctx, len);
2090 return 0;
2091
2092error_path:
2093 audit_panic("error in audit_log_task_context");
2094 return error;
2095}
2096EXPORT_SYMBOL(audit_log_task_context);
2097
2098void audit_log_d_path_exe(struct audit_buffer *ab,
2099 struct mm_struct *mm)
2100{
2101 struct file *exe_file;
2102
2103 if (!mm)
2104 goto out_null;
2105
2106 exe_file = get_mm_exe_file(mm);
2107 if (!exe_file)
2108 goto out_null;
2109
2110 audit_log_d_path(ab, " exe=", &exe_file->f_path);
2111 fput(exe_file);
2112 return;
2113out_null:
2114 audit_log_format(ab, " exe=(null)");
2115}
2116
2117struct tty_struct *audit_get_tty(void)
2118{
2119 struct tty_struct *tty = NULL;
2120 unsigned long flags;
2121
2122 spin_lock_irqsave(&current->sighand->siglock, flags);
2123 if (current->signal)
2124 tty = tty_kref_get(current->signal->tty);
2125 spin_unlock_irqrestore(&current->sighand->siglock, flags);
2126 return tty;
2127}
2128
2129void audit_put_tty(struct tty_struct *tty)
2130{
2131 tty_kref_put(tty);
2132}
2133
2134void audit_log_task_info(struct audit_buffer *ab)
2135{
2136 const struct cred *cred;
2137 char comm[sizeof(current->comm)];
2138 struct tty_struct *tty;
2139
2140 if (!ab)
2141 return;
2142
2143 cred = current_cred();
2144 tty = audit_get_tty();
2145 audit_log_format(ab,
2146 " ppid=%d pid=%d auid=%u uid=%u gid=%u"
2147 " euid=%u suid=%u fsuid=%u"
2148 " egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
2149 task_ppid_nr(current),
2150 task_tgid_nr(current),
2151 from_kuid(&init_user_ns, audit_get_loginuid(current)),
2152 from_kuid(&init_user_ns, cred->uid),
2153 from_kgid(&init_user_ns, cred->gid),
2154 from_kuid(&init_user_ns, cred->euid),
2155 from_kuid(&init_user_ns, cred->suid),
2156 from_kuid(&init_user_ns, cred->fsuid),
2157 from_kgid(&init_user_ns, cred->egid),
2158 from_kgid(&init_user_ns, cred->sgid),
2159 from_kgid(&init_user_ns, cred->fsgid),
2160 tty ? tty_name(tty) : "(none)",
2161 audit_get_sessionid(current));
2162 audit_put_tty(tty);
2163 audit_log_format(ab, " comm=");
2164 audit_log_untrustedstring(ab, get_task_comm(comm, current));
2165 audit_log_d_path_exe(ab, current->mm);
2166 audit_log_task_context(ab);
2167}
2168EXPORT_SYMBOL(audit_log_task_info);
2169
2170/**
2171 * audit_log_link_denied - report a link restriction denial
2172 * @operation: specific link operation
2173 */
2174void audit_log_link_denied(const char *operation)
2175{
2176 struct audit_buffer *ab;
2177
2178 if (!audit_enabled || audit_dummy_context())
2179 return;
2180
2181 /* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */
2182 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_ANOM_LINK);
2183 if (!ab)
2184 return;
2185 audit_log_format(ab, "op=%s", operation);
2186 audit_log_task_info(ab);
2187 audit_log_format(ab, " res=0");
2188 audit_log_end(ab);
2189}
2190
2191/* global counter which is incremented every time something logs in */
2192static atomic_t session_id = ATOMIC_INIT(0);
2193
2194static int audit_set_loginuid_perm(kuid_t loginuid)
2195{
2196 /* if we are unset, we don't need privs */
2197 if (!audit_loginuid_set(current))
2198 return 0;
2199 /* if AUDIT_FEATURE_LOGINUID_IMMUTABLE means never ever allow a change*/
2200 if (is_audit_feature_set(AUDIT_FEATURE_LOGINUID_IMMUTABLE))
2201 return -EPERM;
2202 /* it is set, you need permission */
2203 if (!capable(CAP_AUDIT_CONTROL))
2204 return -EPERM;
2205 /* reject if this is not an unset and we don't allow that */
2206 if (is_audit_feature_set(AUDIT_FEATURE_ONLY_UNSET_LOGINUID)
2207 && uid_valid(loginuid))
2208 return -EPERM;
2209 return 0;
2210}
2211
2212static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
2213 unsigned int oldsessionid,
2214 unsigned int sessionid, int rc)
2215{
2216 struct audit_buffer *ab;
2217 uid_t uid, oldloginuid, loginuid;
2218 struct tty_struct *tty;
2219
2220 if (!audit_enabled)
2221 return;
2222
2223 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_LOGIN);
2224 if (!ab)
2225 return;
2226
2227 uid = from_kuid(&init_user_ns, task_uid(current));
2228 oldloginuid = from_kuid(&init_user_ns, koldloginuid);
2229 loginuid = from_kuid(&init_user_ns, kloginuid),
2230 tty = audit_get_tty();
2231
2232 audit_log_format(ab, "pid=%d uid=%u", task_tgid_nr(current), uid);
2233 audit_log_task_context(ab);
2234 audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",
2235 oldloginuid, loginuid, tty ? tty_name(tty) : "(none)",
2236 oldsessionid, sessionid, !rc);
2237 audit_put_tty(tty);
2238 audit_log_end(ab);
2239}
2240
2241/**
2242 * audit_set_loginuid - set current task's loginuid
2243 * @loginuid: loginuid value
2244 *
2245 * Returns 0.
2246 *
2247 * Called (set) from fs/proc/base.c::proc_loginuid_write().
2248 */
2249int audit_set_loginuid(kuid_t loginuid)
2250{
2251 unsigned int oldsessionid, sessionid = AUDIT_SID_UNSET;
2252 kuid_t oldloginuid;
2253 int rc;
2254
2255 oldloginuid = audit_get_loginuid(current);
2256 oldsessionid = audit_get_sessionid(current);
2257
2258 rc = audit_set_loginuid_perm(loginuid);
2259 if (rc)
2260 goto out;
2261
2262 /* are we setting or clearing? */
2263 if (uid_valid(loginuid)) {
2264 sessionid = (unsigned int)atomic_inc_return(&session_id);
2265 if (unlikely(sessionid == AUDIT_SID_UNSET))
2266 sessionid = (unsigned int)atomic_inc_return(&session_id);
2267 }
2268
2269 current->sessionid = sessionid;
2270 current->loginuid = loginuid;
2271out:
2272 audit_log_set_loginuid(oldloginuid, loginuid, oldsessionid, sessionid, rc);
2273 return rc;
2274}
2275
2276/**
2277 * audit_log_end - end one audit record
2278 * @ab: the audit_buffer
2279 *
2280 * We can not do a netlink send inside an irq context because it blocks (last
2281 * arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a
2282 * queue and a tasklet is scheduled to remove them from the queue outside the
2283 * irq context. May be called in any context.
2284 */
2285void audit_log_end(struct audit_buffer *ab)
2286{
2287 struct sk_buff *skb;
2288 struct nlmsghdr *nlh;
2289
2290 if (!ab)
2291 return;
2292
2293 if (audit_rate_check()) {
2294 skb = ab->skb;
2295 ab->skb = NULL;
2296
2297 /* setup the netlink header, see the comments in
2298 * kauditd_send_multicast_skb() for length quirks */
2299 nlh = nlmsg_hdr(skb);
2300 nlh->nlmsg_len = skb->len - NLMSG_HDRLEN;
2301
2302 /* queue the netlink packet and poke the kauditd thread */
2303 skb_queue_tail(&audit_queue, skb);
2304 wake_up_interruptible(&kauditd_wait);
2305 } else
2306 audit_log_lost("rate limit exceeded");
2307
2308 audit_buffer_free(ab);
2309}
2310
2311/**
2312 * audit_log - Log an audit record
2313 * @ctx: audit context
2314 * @gfp_mask: type of allocation
2315 * @type: audit message type
2316 * @fmt: format string to use
2317 * @...: variable parameters matching the format string
2318 *
2319 * This is a convenience function that calls audit_log_start,
2320 * audit_log_vformat, and audit_log_end. It may be called
2321 * in any context.
2322 */
2323void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
2324 const char *fmt, ...)
2325{
2326 struct audit_buffer *ab;
2327 va_list args;
2328
2329 ab = audit_log_start(ctx, gfp_mask, type);
2330 if (ab) {
2331 va_start(args, fmt);
2332 audit_log_vformat(ab, fmt, args);
2333 va_end(args);
2334 audit_log_end(ab);
2335 }
2336}
2337
2338EXPORT_SYMBOL(audit_log_start);
2339EXPORT_SYMBOL(audit_log_end);
2340EXPORT_SYMBOL(audit_log_format);
2341EXPORT_SYMBOL(audit_log);
2342