projects/linux·blob v6.3-rc3 · refs

2464 lines · 64.8 KiB

1// SPDX-License-Identifier: GPL-2.0-or-later
2/* audit.c -- Auditing support
3 * Gateway between the kernel (e.g., selinux) and the user-space audit daemon.
4 * System-call specific features have moved to auditsc.c
5 *
6 * Copyright 2003-2007 Red Hat Inc., Durham, North Carolina.
7 * All Rights Reserved.
8 *
9 * Written by Rickard E. (Rik) Faith <[email protected]>
10 *
11 * Goals: 1) Integrate fully with Security Modules.
12 * 2) Minimal run-time overhead:
13 * a) Minimal when syscall auditing is disabled (audit_enable=0).
14 * b) Small when syscall auditing is enabled and no audit record
15 * is generated (defer as much work as possible to record
16 * generation time):
17 * i) context is allocated,
18 * ii) names from getname are stored without a copy, and
19 * iii) inode information stored from path_lookup.
20 * 3) Ability to disable syscall auditing at boot time (audit=0).
21 * 4) Usable by other parts of the kernel (if audit_log* is called,
22 * then a syscall record will be generated automatically for the
23 * current syscall).
24 * 5) Netlink interface to user-space.
25 * 6) Support low-overhead kernel-based filtering to minimize the
26 * information that must be passed to user-space.
27 *
28 * Audit userspace, documentation, tests, and bug/issue trackers:
29 * https://github.com/linux-audit
30 */
31
32#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
33
34#include <linux/file.h>
35#include <linux/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 = AUDIT_UNINITIALIZED;
71
72u32 audit_enabled = AUDIT_OFF;
73bool audit_ever_enabled = !!AUDIT_OFF;
74
75EXPORT_SYMBOL_GPL(audit_enabled);
76
77/* Default state when kernel boots without any parameters. */
78static u32 audit_default = AUDIT_OFF;
79
80/* If auditing cannot proceed, audit_failure selects what happens. */
81static u32 audit_failure = AUDIT_FAIL_PRINTK;
82
83/* private audit network namespace index */
84static unsigned int audit_net_id;
85
86/**
87 * struct audit_net - audit private network namespace data
88 * @sk: communication socket
89 */
90struct audit_net {
91 struct sock *sk;
92};
93
94/**
95 * struct auditd_connection - kernel/auditd connection state
96 * @pid: auditd PID
97 * @portid: netlink portid
98 * @net: the associated network namespace
99 * @rcu: RCU head
100 *
101 * Description:
102 * This struct is RCU protected; you must either hold the RCU lock for reading
103 * or the associated spinlock for writing.
104 */
105struct auditd_connection {
106 struct pid *pid;
107 u32 portid;
108 struct net *net;
109 struct rcu_head rcu;
110};
111static struct auditd_connection __rcu *auditd_conn;
112static DEFINE_SPINLOCK(auditd_conn_lock);
113
114/* If audit_rate_limit is non-zero, limit the rate of sending audit records
115 * to that number per second. This prevents DoS attacks, but results in
116 * audit records being dropped. */
117static u32 audit_rate_limit;
118
119/* Number of outstanding audit_buffers allowed.
120 * When set to zero, this means unlimited. */
121static u32 audit_backlog_limit = 64;
122#define AUDIT_BACKLOG_WAIT_TIME (60 * HZ)
123static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
124
125/* The identity of the user shutting down the audit system. */
126static kuid_t audit_sig_uid = INVALID_UID;
127static pid_t audit_sig_pid = -1;
128static u32 audit_sig_sid;
129
130/* Records can be lost in several ways:
131 0) [suppressed in audit_alloc]
132 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
133 2) out of memory in audit_log_move [alloc_skb]
134 3) suppressed due to audit_rate_limit
135 4) suppressed due to audit_backlog_limit
136*/
137static atomic_t audit_lost = ATOMIC_INIT(0);
138
139/* Monotonically increasing sum of time the kernel has spent
140 * waiting while the backlog limit is exceeded.
141 */
142static atomic_t audit_backlog_wait_time_actual = ATOMIC_INIT(0);
143
144/* Hash for inode-based rules */
145struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
146
147static struct kmem_cache *audit_buffer_cache;
148
149/* queue msgs to send via kauditd_task */
150static struct sk_buff_head audit_queue;
151/* queue msgs due to temporary unicast send problems */
152static struct sk_buff_head audit_retry_queue;
153/* queue msgs waiting for new auditd connection */
154static struct sk_buff_head audit_hold_queue;
155
156/* queue servicing thread */
157static struct task_struct *kauditd_task;
158static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
159
160/* waitqueue for callers who are blocked on the audit backlog */
161static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
162
163static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION,
164 .mask = -1,
165 .features = 0,
166 .lock = 0,};
167
168static char *audit_feature_names[2] = {
169 "only_unset_loginuid",
170 "loginuid_immutable",
171};
172
173/**
174 * struct audit_ctl_mutex - serialize requests from userspace
175 * @lock: the mutex used for locking
176 * @owner: the task which owns the lock
177 *
178 * Description:
179 * This is the lock struct used to ensure we only process userspace requests
180 * in an orderly fashion. We can't simply use a mutex/lock here because we
181 * need to track lock ownership so we don't end up blocking the lock owner in
182 * audit_log_start() or similar.
183 */
184static struct audit_ctl_mutex {
185 struct mutex lock;
186 void *owner;
187} audit_cmd_mutex;
188
189/* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
190 * audit records. Since printk uses a 1024 byte buffer, this buffer
191 * should be at least that large. */
192#define AUDIT_BUFSIZ 1024
193
194/* The audit_buffer is used when formatting an audit record. The caller
195 * locks briefly to get the record off the freelist or to allocate the
196 * buffer, and locks briefly to send the buffer to the netlink layer or
197 * to place it on a transmit queue. Multiple audit_buffers can be in
198 * use simultaneously. */
199struct audit_buffer {
200 struct sk_buff *skb; /* formatted skb ready to send */
201 struct audit_context *ctx; /* NULL or associated context */
202 gfp_t gfp_mask;
203};
204
205struct audit_reply {
206 __u32 portid;
207 struct net *net;
208 struct sk_buff *skb;
209};
210
211/**
212 * auditd_test_task - Check to see if a given task is an audit daemon
213 * @task: the task to check
214 *
215 * Description:
216 * Return 1 if the task is a registered audit daemon, 0 otherwise.
217 */
218int auditd_test_task(struct task_struct *task)
219{
220 int rc;
221 struct auditd_connection *ac;
222
223 rcu_read_lock();
224 ac = rcu_dereference(auditd_conn);
225 rc = (ac && ac->pid == task_tgid(task) ? 1 : 0);
226 rcu_read_unlock();
227
228 return rc;
229}
230
231/**
232 * audit_ctl_lock - Take the audit control lock
233 */
234void audit_ctl_lock(void)
235{
236 mutex_lock(&audit_cmd_mutex.lock);
237 audit_cmd_mutex.owner = current;
238}
239
240/**
241 * audit_ctl_unlock - Drop the audit control lock
242 */
243void audit_ctl_unlock(void)
244{
245 audit_cmd_mutex.owner = NULL;
246 mutex_unlock(&audit_cmd_mutex.lock);
247}
248
249/**
250 * audit_ctl_owner_current - Test to see if the current task owns the lock
251 *
252 * Description:
253 * Return true if the current task owns the audit control lock, false if it
254 * doesn't own the lock.
255 */
256static bool audit_ctl_owner_current(void)
257{
258 return (current == audit_cmd_mutex.owner);
259}
260
261/**
262 * auditd_pid_vnr - Return the auditd PID relative to the namespace
263 *
264 * Description:
265 * Returns the PID in relation to the namespace, 0 on failure.
266 */
267static pid_t auditd_pid_vnr(void)
268{
269 pid_t pid;
270 const struct auditd_connection *ac;
271
272 rcu_read_lock();
273 ac = rcu_dereference(auditd_conn);
274 if (!ac || !ac->pid)
275 pid = 0;
276 else
277 pid = pid_vnr(ac->pid);
278 rcu_read_unlock();
279
280 return pid;
281}
282
283/**
284 * audit_get_sk - Return the audit socket for the given network namespace
285 * @net: the destination network namespace
286 *
287 * Description:
288 * Returns the sock pointer if valid, NULL otherwise. The caller must ensure
289 * that a reference is held for the network namespace while the sock is in use.
290 */
291static struct sock *audit_get_sk(const struct net *net)
292{
293 struct audit_net *aunet;
294
295 if (!net)
296 return NULL;
297
298 aunet = net_generic(net, audit_net_id);
299 return aunet->sk;
300}
301
302void audit_panic(const char *message)
303{
304 switch (audit_failure) {
305 case AUDIT_FAIL_SILENT:
306 break;
307 case AUDIT_FAIL_PRINTK:
308 if (printk_ratelimit())
309 pr_err("%s\n", message);
310 break;
311 case AUDIT_FAIL_PANIC:
312 panic("audit: %s\n", message);
313 break;
314 }
315}
316
317static inline int audit_rate_check(void)
318{
319 static unsigned long last_check = 0;
320 static int messages = 0;
321 static DEFINE_SPINLOCK(lock);
322 unsigned long flags;
323 unsigned long now;
324 int retval = 0;
325
326 if (!audit_rate_limit) return 1;
327
328 spin_lock_irqsave(&lock, flags);
329 if (++messages < audit_rate_limit) {
330 retval = 1;
331 } else {
332 now = jiffies;
333 if (time_after(now, last_check + HZ)) {
334 last_check = now;
335 messages = 0;
336 retval = 1;
337 }
338 }
339 spin_unlock_irqrestore(&lock, flags);
340
341 return retval;
342}
343
344/**
345 * audit_log_lost - conditionally log lost audit message event
346 * @message: the message stating reason for lost audit message
347 *
348 * Emit at least 1 message per second, even if audit_rate_check is
349 * throttling.
350 * Always increment the lost messages counter.
351*/
352void audit_log_lost(const char *message)
353{
354 static unsigned long last_msg = 0;
355 static DEFINE_SPINLOCK(lock);
356 unsigned long flags;
357 unsigned long now;
358 int print;
359
360 atomic_inc(&audit_lost);
361
362 print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
363
364 if (!print) {
365 spin_lock_irqsave(&lock, flags);
366 now = jiffies;
367 if (time_after(now, last_msg + HZ)) {
368 print = 1;
369 last_msg = now;
370 }
371 spin_unlock_irqrestore(&lock, flags);
372 }
373
374 if (print) {
375 if (printk_ratelimit())
376 pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
377 atomic_read(&audit_lost),
378 audit_rate_limit,
379 audit_backlog_limit);
380 audit_panic(message);
381 }
382}
383
384static int audit_log_config_change(char *function_name, u32 new, u32 old,
385 int allow_changes)
386{
387 struct audit_buffer *ab;
388 int rc = 0;
389
390 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
391 if (unlikely(!ab))
392 return rc;
393 audit_log_format(ab, "op=set %s=%u old=%u ", function_name, new, old);
394 audit_log_session_info(ab);
395 rc = audit_log_task_context(ab);
396 if (rc)
397 allow_changes = 0; /* Something weird, deny request */
398 audit_log_format(ab, " res=%d", allow_changes);
399 audit_log_end(ab);
400 return rc;
401}
402
403static int audit_do_config_change(char *function_name, u32 *to_change, u32 new)
404{
405 int allow_changes, rc = 0;
406 u32 old = *to_change;
407
408 /* check if we are locked */
409 if (audit_enabled == AUDIT_LOCKED)
410 allow_changes = 0;
411 else
412 allow_changes = 1;
413
414 if (audit_enabled != AUDIT_OFF) {
415 rc = audit_log_config_change(function_name, new, old, allow_changes);
416 if (rc)
417 allow_changes = 0;
418 }
419
420 /* If we are allowed, make the change */
421 if (allow_changes == 1)
422 *to_change = new;
423 /* Not allowed, update reason */
424 else if (rc == 0)
425 rc = -EPERM;
426 return rc;
427}
428
429static int audit_set_rate_limit(u32 limit)
430{
431 return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit);
432}
433
434static int audit_set_backlog_limit(u32 limit)
435{
436 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit);
437}
438
439static int audit_set_backlog_wait_time(u32 timeout)
440{
441 return audit_do_config_change("audit_backlog_wait_time",
442 &audit_backlog_wait_time, timeout);
443}
444
445static int audit_set_enabled(u32 state)
446{
447 int rc;
448 if (state > AUDIT_LOCKED)
449 return -EINVAL;
450
451 rc = audit_do_config_change("audit_enabled", &audit_enabled, state);
452 if (!rc)
453 audit_ever_enabled |= !!state;
454
455 return rc;
456}
457
458static int audit_set_failure(u32 state)
459{
460 if (state != AUDIT_FAIL_SILENT
461 && state != AUDIT_FAIL_PRINTK
462 && state != AUDIT_FAIL_PANIC)
463 return -EINVAL;
464
465 return audit_do_config_change("audit_failure", &audit_failure, state);
466}
467
468/**
469 * auditd_conn_free - RCU helper to release an auditd connection struct
470 * @rcu: RCU head
471 *
472 * Description:
473 * Drop any references inside the auditd connection tracking struct and free
474 * the memory.
475 */
476static void auditd_conn_free(struct rcu_head *rcu)
477{
478 struct auditd_connection *ac;
479
480 ac = container_of(rcu, struct auditd_connection, rcu);
481 put_pid(ac->pid);
482 put_net(ac->net);
483 kfree(ac);
484}
485
486/**
487 * auditd_set - Set/Reset the auditd connection state
488 * @pid: auditd PID
489 * @portid: auditd netlink portid
490 * @net: auditd network namespace pointer
491 *
492 * Description:
493 * This function will obtain and drop network namespace references as
494 * necessary. Returns zero on success, negative values on failure.
495 */
496static int auditd_set(struct pid *pid, u32 portid, struct net *net)
497{
498 unsigned long flags;
499 struct auditd_connection *ac_old, *ac_new;
500
501 if (!pid || !net)
502 return -EINVAL;
503
504 ac_new = kzalloc(sizeof(*ac_new), GFP_KERNEL);
505 if (!ac_new)
506 return -ENOMEM;
507 ac_new->pid = get_pid(pid);
508 ac_new->portid = portid;
509 ac_new->net = get_net(net);
510
511 spin_lock_irqsave(&auditd_conn_lock, flags);
512 ac_old = rcu_dereference_protected(auditd_conn,
513 lockdep_is_held(&auditd_conn_lock));
514 rcu_assign_pointer(auditd_conn, ac_new);
515 spin_unlock_irqrestore(&auditd_conn_lock, flags);
516
517 if (ac_old)
518 call_rcu(&ac_old->rcu, auditd_conn_free);
519
520 return 0;
521}
522
523/**
524 * kauditd_printk_skb - Print the audit record to the ring buffer
525 * @skb: audit record
526 *
527 * Whatever the reason, this packet may not make it to the auditd connection
528 * so write it via printk so the information isn't completely lost.
529 */
530static void kauditd_printk_skb(struct sk_buff *skb)
531{
532 struct nlmsghdr *nlh = nlmsg_hdr(skb);
533 char *data = nlmsg_data(nlh);
534
535 if (nlh->nlmsg_type != AUDIT_EOE && printk_ratelimit())
536 pr_notice("type=%d %s\n", nlh->nlmsg_type, data);
537}
538
539/**
540 * kauditd_rehold_skb - Handle a audit record send failure in the hold queue
541 * @skb: audit record
542 * @error: error code (unused)
543 *
544 * Description:
545 * This should only be used by the kauditd_thread when it fails to flush the
546 * hold queue.
547 */
548static void kauditd_rehold_skb(struct sk_buff *skb, __always_unused int error)
549{
550 /* put the record back in the queue */
551 skb_queue_tail(&audit_hold_queue, skb);
552}
553
554/**
555 * kauditd_hold_skb - Queue an audit record, waiting for auditd
556 * @skb: audit record
557 * @error: error code
558 *
559 * Description:
560 * Queue the audit record, waiting for an instance of auditd. When this
561 * function is called we haven't given up yet on sending the record, but things
562 * are not looking good. The first thing we want to do is try to write the
563 * record via printk and then see if we want to try and hold on to the record
564 * and queue it, if we have room. If we want to hold on to the record, but we
565 * don't have room, record a record lost message.
566 */
567static void kauditd_hold_skb(struct sk_buff *skb, int error)
568{
569 /* at this point it is uncertain if we will ever send this to auditd so
570 * try to send the message via printk before we go any further */
571 kauditd_printk_skb(skb);
572
573 /* can we just silently drop the message? */
574 if (!audit_default)
575 goto drop;
576
577 /* the hold queue is only for when the daemon goes away completely,
578 * not -EAGAIN failures; if we are in a -EAGAIN state requeue the
579 * record on the retry queue unless it's full, in which case drop it
580 */
581 if (error == -EAGAIN) {
582 if (!audit_backlog_limit ||
583 skb_queue_len(&audit_retry_queue) < audit_backlog_limit) {
584 skb_queue_tail(&audit_retry_queue, skb);
585 return;
586 }
587 audit_log_lost("kauditd retry queue overflow");
588 goto drop;
589 }
590
591 /* if we have room in the hold queue, queue the message */
592 if (!audit_backlog_limit ||
593 skb_queue_len(&audit_hold_queue) < audit_backlog_limit) {
594 skb_queue_tail(&audit_hold_queue, skb);
595 return;
596 }
597
598 /* we have no other options - drop the message */
599 audit_log_lost("kauditd hold queue overflow");
600drop:
601 kfree_skb(skb);
602}
603
604/**
605 * kauditd_retry_skb - Queue an audit record, attempt to send again to auditd
606 * @skb: audit record
607 * @error: error code (unused)
608 *
609 * Description:
610 * Not as serious as kauditd_hold_skb() as we still have a connected auditd,
611 * but for some reason we are having problems sending it audit records so
612 * queue the given record and attempt to resend.
613 */
614static void kauditd_retry_skb(struct sk_buff *skb, __always_unused int error)
615{
616 if (!audit_backlog_limit ||
617 skb_queue_len(&audit_retry_queue) < audit_backlog_limit) {
618 skb_queue_tail(&audit_retry_queue, skb);
619 return;
620 }
621
622 /* we have to drop the record, send it via printk as a last effort */
623 kauditd_printk_skb(skb);
624 audit_log_lost("kauditd retry queue overflow");
625 kfree_skb(skb);
626}
627
628/**
629 * auditd_reset - Disconnect the auditd connection
630 * @ac: auditd connection state
631 *
632 * Description:
633 * Break the auditd/kauditd connection and move all the queued records into the
634 * hold queue in case auditd reconnects. It is important to note that the @ac
635 * pointer should never be dereferenced inside this function as it may be NULL
636 * or invalid, you can only compare the memory address! If @ac is NULL then
637 * the connection will always be reset.
638 */
639static void auditd_reset(const struct auditd_connection *ac)
640{
641 unsigned long flags;
642 struct sk_buff *skb;
643 struct auditd_connection *ac_old;
644
645 /* if it isn't already broken, break the connection */
646 spin_lock_irqsave(&auditd_conn_lock, flags);
647 ac_old = rcu_dereference_protected(auditd_conn,
648 lockdep_is_held(&auditd_conn_lock));
649 if (ac && ac != ac_old) {
650 /* someone already registered a new auditd connection */
651 spin_unlock_irqrestore(&auditd_conn_lock, flags);
652 return;
653 }
654 rcu_assign_pointer(auditd_conn, NULL);
655 spin_unlock_irqrestore(&auditd_conn_lock, flags);
656
657 if (ac_old)
658 call_rcu(&ac_old->rcu, auditd_conn_free);
659
660 /* flush the retry queue to the hold queue, but don't touch the main
661 * queue since we need to process that normally for multicast */
662 while ((skb = skb_dequeue(&audit_retry_queue)))
663 kauditd_hold_skb(skb, -ECONNREFUSED);
664}
665
666/**
667 * auditd_send_unicast_skb - Send a record via unicast to auditd
668 * @skb: audit record
669 *
670 * Description:
671 * Send a skb to the audit daemon, returns positive/zero values on success and
672 * negative values on failure; in all cases the skb will be consumed by this
673 * function. If the send results in -ECONNREFUSED the connection with auditd
674 * will be reset. This function may sleep so callers should not hold any locks
675 * where this would cause a problem.
676 */
677static int auditd_send_unicast_skb(struct sk_buff *skb)
678{
679 int rc;
680 u32 portid;
681 struct net *net;
682 struct sock *sk;
683 struct auditd_connection *ac;
684
685 /* NOTE: we can't call netlink_unicast while in the RCU section so
686 * take a reference to the network namespace and grab local
687 * copies of the namespace, the sock, and the portid; the
688 * namespace and sock aren't going to go away while we hold a
689 * reference and if the portid does become invalid after the RCU
690 * section netlink_unicast() should safely return an error */
691
692 rcu_read_lock();
693 ac = rcu_dereference(auditd_conn);
694 if (!ac) {
695 rcu_read_unlock();
696 kfree_skb(skb);
697 rc = -ECONNREFUSED;
698 goto err;
699 }
700 net = get_net(ac->net);
701 sk = audit_get_sk(net);
702 portid = ac->portid;
703 rcu_read_unlock();
704
705 rc = netlink_unicast(sk, skb, portid, 0);
706 put_net(net);
707 if (rc < 0)
708 goto err;
709
710 return rc;
711
712err:
713 if (ac && rc == -ECONNREFUSED)
714 auditd_reset(ac);
715 return rc;
716}
717
718/**
719 * kauditd_send_queue - Helper for kauditd_thread to flush skb queues
720 * @sk: the sending sock
721 * @portid: the netlink destination
722 * @queue: the skb queue to process
723 * @retry_limit: limit on number of netlink unicast failures
724 * @skb_hook: per-skb hook for additional processing
725 * @err_hook: hook called if the skb fails the netlink unicast send
726 *
727 * Description:
728 * Run through the given queue and attempt to send the audit records to auditd,
729 * returns zero on success, negative values on failure. It is up to the caller
730 * to ensure that the @sk is valid for the duration of this function.
731 *
732 */
733static int kauditd_send_queue(struct sock *sk, u32 portid,
734 struct sk_buff_head *queue,
735 unsigned int retry_limit,
736 void (*skb_hook)(struct sk_buff *skb),
737 void (*err_hook)(struct sk_buff *skb, int error))
738{
739 int rc = 0;
740 struct sk_buff *skb = NULL;
741 struct sk_buff *skb_tail;
742 unsigned int failed = 0;
743
744 /* NOTE: kauditd_thread takes care of all our locking, we just use
745 * the netlink info passed to us (e.g. sk and portid) */
746
747 skb_tail = skb_peek_tail(queue);
748 while ((skb != skb_tail) && (skb = skb_dequeue(queue))) {
749 /* call the skb_hook for each skb we touch */
750 if (skb_hook)
751 (*skb_hook)(skb);
752
753 /* can we send to anyone via unicast? */
754 if (!sk) {
755 if (err_hook)
756 (*err_hook)(skb, -ECONNREFUSED);
757 continue;
758 }
759
760retry:
761 /* grab an extra skb reference in case of error */
762 skb_get(skb);
763 rc = netlink_unicast(sk, skb, portid, 0);
764 if (rc < 0) {
765 /* send failed - try a few times unless fatal error */
766 if (++failed >= retry_limit ||
767 rc == -ECONNREFUSED || rc == -EPERM) {
768 sk = NULL;
769 if (err_hook)
770 (*err_hook)(skb, rc);
771 if (rc == -EAGAIN)
772 rc = 0;
773 /* continue to drain the queue */
774 continue;
775 } else
776 goto retry;
777 } else {
778 /* skb sent - drop the extra reference and continue */
779 consume_skb(skb);
780 failed = 0;
781 }
782 }
783
784 return (rc >= 0 ? 0 : rc);
785}
786
787/*
788 * kauditd_send_multicast_skb - Send a record to any multicast listeners
789 * @skb: audit record
790 *
791 * Description:
792 * Write a multicast message to anyone listening in the initial network
793 * namespace. This function doesn't consume an skb as might be expected since
794 * it has to copy it anyways.
795 */
796static void kauditd_send_multicast_skb(struct sk_buff *skb)
797{
798 struct sk_buff *copy;
799 struct sock *sock = audit_get_sk(&init_net);
800 struct nlmsghdr *nlh;
801
802 /* NOTE: we are not taking an additional reference for init_net since
803 * we don't have to worry about it going away */
804
805 if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
806 return;
807
808 /*
809 * The seemingly wasteful skb_copy() rather than bumping the refcount
810 * using skb_get() is necessary because non-standard mods are made to
811 * the skb by the original kaudit unicast socket send routine. The
812 * existing auditd daemon assumes this breakage. Fixing this would
813 * require co-ordinating a change in the established protocol between
814 * the kaudit kernel subsystem and the auditd userspace code. There is
815 * no reason for new multicast clients to continue with this
816 * non-compliance.
817 */
818 copy = skb_copy(skb, GFP_KERNEL);
819 if (!copy)
820 return;
821 nlh = nlmsg_hdr(copy);
822 nlh->nlmsg_len = skb->len;
823
824 nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL);
825}
826
827/**
828 * kauditd_thread - Worker thread to send audit records to userspace
829 * @dummy: unused
830 */
831static int kauditd_thread(void *dummy)
832{
833 int rc;
834 u32 portid = 0;
835 struct net *net = NULL;
836 struct sock *sk = NULL;
837 struct auditd_connection *ac;
838
839#define UNICAST_RETRIES 5
840
841 set_freezable();
842 while (!kthread_should_stop()) {
843 /* NOTE: see the lock comments in auditd_send_unicast_skb() */
844 rcu_read_lock();
845 ac = rcu_dereference(auditd_conn);
846 if (!ac) {
847 rcu_read_unlock();
848 goto main_queue;
849 }
850 net = get_net(ac->net);
851 sk = audit_get_sk(net);
852 portid = ac->portid;
853 rcu_read_unlock();
854
855 /* attempt to flush the hold queue */
856 rc = kauditd_send_queue(sk, portid,
857 &audit_hold_queue, UNICAST_RETRIES,
858 NULL, kauditd_rehold_skb);
859 if (rc < 0) {
860 sk = NULL;
861 auditd_reset(ac);
862 goto main_queue;
863 }
864
865 /* attempt to flush the retry queue */
866 rc = kauditd_send_queue(sk, portid,
867 &audit_retry_queue, UNICAST_RETRIES,
868 NULL, kauditd_hold_skb);
869 if (rc < 0) {
870 sk = NULL;
871 auditd_reset(ac);
872 goto main_queue;
873 }
874
875main_queue:
876 /* process the main queue - do the multicast send and attempt
877 * unicast, dump failed record sends to the retry queue; if
878 * sk == NULL due to previous failures we will just do the
879 * multicast send and move the record to the hold queue */
880 rc = kauditd_send_queue(sk, portid, &audit_queue, 1,
881 kauditd_send_multicast_skb,
882 (sk ?
883 kauditd_retry_skb : kauditd_hold_skb));
884 if (ac && rc < 0)
885 auditd_reset(ac);
886 sk = NULL;
887
888 /* drop our netns reference, no auditd sends past this line */
889 if (net) {
890 put_net(net);
891 net = NULL;
892 }
893
894 /* we have processed all the queues so wake everyone */
895 wake_up(&audit_backlog_wait);
896
897 /* NOTE: we want to wake up if there is anything on the queue,
898 * regardless of if an auditd is connected, as we need to
899 * do the multicast send and rotate records from the
900 * main queue to the retry/hold queues */
901 wait_event_freezable(kauditd_wait,
902 (skb_queue_len(&audit_queue) ? 1 : 0));
903 }
904
905 return 0;
906}
907
908int audit_send_list_thread(void *_dest)
909{
910 struct audit_netlink_list *dest = _dest;
911 struct sk_buff *skb;
912 struct sock *sk = audit_get_sk(dest->net);
913
914 /* wait for parent to finish and send an ACK */
915 audit_ctl_lock();
916 audit_ctl_unlock();
917
918 while ((skb = __skb_dequeue(&dest->q)) != NULL)
919 netlink_unicast(sk, skb, dest->portid, 0);
920
921 put_net(dest->net);
922 kfree(dest);
923
924 return 0;
925}
926
927struct sk_buff *audit_make_reply(int seq, int type, int done,
928 int multi, const void *payload, int size)
929{
930 struct sk_buff *skb;
931 struct nlmsghdr *nlh;
932 void *data;
933 int flags = multi ? NLM_F_MULTI : 0;
934 int t = done ? NLMSG_DONE : type;
935
936 skb = nlmsg_new(size, GFP_KERNEL);
937 if (!skb)
938 return NULL;
939
940 nlh = nlmsg_put(skb, 0, seq, t, size, flags);
941 if (!nlh)
942 goto out_kfree_skb;
943 data = nlmsg_data(nlh);
944 memcpy(data, payload, size);
945 return skb;
946
947out_kfree_skb:
948 kfree_skb(skb);
949 return NULL;
950}
951
952static void audit_free_reply(struct audit_reply *reply)
953{
954 if (!reply)
955 return;
956
957 kfree_skb(reply->skb);
958 if (reply->net)
959 put_net(reply->net);
960 kfree(reply);
961}
962
963static int audit_send_reply_thread(void *arg)
964{
965 struct audit_reply *reply = (struct audit_reply *)arg;
966
967 audit_ctl_lock();
968 audit_ctl_unlock();
969
970 /* Ignore failure. It'll only happen if the sender goes away,
971 because our timeout is set to infinite. */
972 netlink_unicast(audit_get_sk(reply->net), reply->skb, reply->portid, 0);
973 reply->skb = NULL;
974 audit_free_reply(reply);
975 return 0;
976}
977
978/**
979 * audit_send_reply - send an audit reply message via netlink
980 * @request_skb: skb of request we are replying to (used to target the reply)
981 * @seq: sequence number
982 * @type: audit message type
983 * @done: done (last) flag
984 * @multi: multi-part message flag
985 * @payload: payload data
986 * @size: payload size
987 *
988 * Allocates a skb, builds the netlink message, and sends it to the port id.
989 */
990static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
991 int multi, const void *payload, int size)
992{
993 struct task_struct *tsk;
994 struct audit_reply *reply;
995
996 reply = kzalloc(sizeof(*reply), GFP_KERNEL);
997 if (!reply)
998 return;
999
1000 reply->skb = audit_make_reply(seq, type, done, multi, payload, size);
1001 if (!reply->skb)
1002 goto err;
1003 reply->net = get_net(sock_net(NETLINK_CB(request_skb).sk));
1004 reply->portid = NETLINK_CB(request_skb).portid;
1005
1006 tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
1007 if (IS_ERR(tsk))
1008 goto err;
1009
1010 return;
1011
1012err:
1013 audit_free_reply(reply);
1014}
1015
1016/*
1017 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
1018 * control messages.
1019 */
1020static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
1021{
1022 int err = 0;
1023
1024 /* Only support initial user namespace for now. */
1025 /*
1026 * We return ECONNREFUSED because it tricks userspace into thinking
1027 * that audit was not configured into the kernel. Lots of users
1028 * configure their PAM stack (because that's what the distro does)
1029 * to reject login if unable to send messages to audit. If we return
1030 * ECONNREFUSED the PAM stack thinks the kernel does not have audit
1031 * configured in and will let login proceed. If we return EPERM
1032 * userspace will reject all logins. This should be removed when we
1033 * support non init namespaces!!
1034 */
1035 if (current_user_ns() != &init_user_ns)
1036 return -ECONNREFUSED;
1037
1038 switch (msg_type) {
1039 case AUDIT_LIST:
1040 case AUDIT_ADD:
1041 case AUDIT_DEL:
1042 return -EOPNOTSUPP;
1043 case AUDIT_GET:
1044 case AUDIT_SET:
1045 case AUDIT_GET_FEATURE:
1046 case AUDIT_SET_FEATURE:
1047 case AUDIT_LIST_RULES:
1048 case AUDIT_ADD_RULE:
1049 case AUDIT_DEL_RULE:
1050 case AUDIT_SIGNAL_INFO:
1051 case AUDIT_TTY_GET:
1052 case AUDIT_TTY_SET:
1053 case AUDIT_TRIM:
1054 case AUDIT_MAKE_EQUIV:
1055 /* Only support auditd and auditctl in initial pid namespace
1056 * for now. */
1057 if (task_active_pid_ns(current) != &init_pid_ns)
1058 return -EPERM;
1059
1060 if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
1061 err = -EPERM;
1062 break;
1063 case AUDIT_USER:
1064 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1065 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1066 if (!netlink_capable(skb, CAP_AUDIT_WRITE))
1067 err = -EPERM;
1068 break;
1069 default: /* bad msg */
1070 err = -EINVAL;
1071 }
1072
1073 return err;
1074}
1075
1076static void audit_log_common_recv_msg(struct audit_context *context,
1077 struct audit_buffer **ab, u16 msg_type)
1078{
1079 uid_t uid = from_kuid(&init_user_ns, current_uid());
1080 pid_t pid = task_tgid_nr(current);
1081
1082 if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
1083 *ab = NULL;
1084 return;
1085 }
1086
1087 *ab = audit_log_start(context, GFP_KERNEL, msg_type);
1088 if (unlikely(!*ab))
1089 return;
1090 audit_log_format(*ab, "pid=%d uid=%u ", pid, uid);
1091 audit_log_session_info(*ab);
1092 audit_log_task_context(*ab);
1093}
1094
1095static inline void audit_log_user_recv_msg(struct audit_buffer **ab,
1096 u16 msg_type)
1097{
1098 audit_log_common_recv_msg(NULL, ab, msg_type);
1099}
1100
1101static int is_audit_feature_set(int i)
1102{
1103 return af.features & AUDIT_FEATURE_TO_MASK(i);
1104}
1105
1106
1107static int audit_get_feature(struct sk_buff *skb)
1108{
1109 u32 seq;
1110
1111 seq = nlmsg_hdr(skb)->nlmsg_seq;
1112
1113 audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af));
1114
1115 return 0;
1116}
1117
1118static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
1119 u32 old_lock, u32 new_lock, int res)
1120{
1121 struct audit_buffer *ab;
1122
1123 if (audit_enabled == AUDIT_OFF)
1124 return;
1125
1126 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_FEATURE_CHANGE);
1127 if (!ab)
1128 return;
1129 audit_log_task_info(ab);
1130 audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
1131 audit_feature_names[which], !!old_feature, !!new_feature,
1132 !!old_lock, !!new_lock, res);
1133 audit_log_end(ab);
1134}
1135
1136static int audit_set_feature(struct audit_features *uaf)
1137{
1138 int i;
1139
1140 BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
1141
1142 /* if there is ever a version 2 we should handle that here */
1143
1144 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1145 u32 feature = AUDIT_FEATURE_TO_MASK(i);
1146 u32 old_feature, new_feature, old_lock, new_lock;
1147
1148 /* if we are not changing this feature, move along */
1149 if (!(feature & uaf->mask))
1150 continue;
1151
1152 old_feature = af.features & feature;
1153 new_feature = uaf->features & feature;
1154 new_lock = (uaf->lock | af.lock) & feature;
1155 old_lock = af.lock & feature;
1156
1157 /* are we changing a locked feature? */
1158 if (old_lock && (new_feature != old_feature)) {
1159 audit_log_feature_change(i, old_feature, new_feature,
1160 old_lock, new_lock, 0);
1161 return -EPERM;
1162 }
1163 }
1164 /* nothing invalid, do the changes */
1165 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1166 u32 feature = AUDIT_FEATURE_TO_MASK(i);
1167 u32 old_feature, new_feature, old_lock, new_lock;
1168
1169 /* if we are not changing this feature, move along */
1170 if (!(feature & uaf->mask))
1171 continue;
1172
1173 old_feature = af.features & feature;
1174 new_feature = uaf->features & feature;
1175 old_lock = af.lock & feature;
1176 new_lock = (uaf->lock | af.lock) & feature;
1177
1178 if (new_feature != old_feature)
1179 audit_log_feature_change(i, old_feature, new_feature,
1180 old_lock, new_lock, 1);
1181
1182 if (new_feature)
1183 af.features |= feature;
1184 else
1185 af.features &= ~feature;
1186 af.lock |= new_lock;
1187 }
1188
1189 return 0;
1190}
1191
1192static int audit_replace(struct pid *pid)
1193{
1194 pid_t pvnr;
1195 struct sk_buff *skb;
1196
1197 pvnr = pid_vnr(pid);
1198 skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pvnr, sizeof(pvnr));
1199 if (!skb)
1200 return -ENOMEM;
1201 return auditd_send_unicast_skb(skb);
1202}
1203
1204static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
1205{
1206 u32 seq;
1207 void *data;
1208 int data_len;
1209 int err;
1210 struct audit_buffer *ab;
1211 u16 msg_type = nlh->nlmsg_type;
1212 struct audit_sig_info *sig_data;
1213 char *ctx = NULL;
1214 u32 len;
1215
1216 err = audit_netlink_ok(skb, msg_type);
1217 if (err)
1218 return err;
1219
1220 seq = nlh->nlmsg_seq;
1221 data = nlmsg_data(nlh);
1222 data_len = nlmsg_len(nlh);
1223
1224 switch (msg_type) {
1225 case AUDIT_GET: {
1226 struct audit_status s;
1227 memset(&s, 0, sizeof(s));
1228 s.enabled = audit_enabled;
1229 s.failure = audit_failure;
1230 /* NOTE: use pid_vnr() so the PID is relative to the current
1231 * namespace */
1232 s.pid = auditd_pid_vnr();
1233 s.rate_limit = audit_rate_limit;
1234 s.backlog_limit = audit_backlog_limit;
1235 s.lost = atomic_read(&audit_lost);
1236 s.backlog = skb_queue_len(&audit_queue);
1237 s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL;
1238 s.backlog_wait_time = audit_backlog_wait_time;
1239 s.backlog_wait_time_actual = atomic_read(&audit_backlog_wait_time_actual);
1240 audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
1241 break;
1242 }
1243 case AUDIT_SET: {
1244 struct audit_status s;
1245 memset(&s, 0, sizeof(s));
1246 /* guard against past and future API changes */
1247 memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
1248 if (s.mask & AUDIT_STATUS_ENABLED) {
1249 err = audit_set_enabled(s.enabled);
1250 if (err < 0)
1251 return err;
1252 }
1253 if (s.mask & AUDIT_STATUS_FAILURE) {
1254 err = audit_set_failure(s.failure);
1255 if (err < 0)
1256 return err;
1257 }
1258 if (s.mask & AUDIT_STATUS_PID) {
1259 /* NOTE: we are using the vnr PID functions below
1260 * because the s.pid value is relative to the
1261 * namespace of the caller; at present this
1262 * doesn't matter much since you can really only
1263 * run auditd from the initial pid namespace, but
1264 * something to keep in mind if this changes */
1265 pid_t new_pid = s.pid;
1266 pid_t auditd_pid;
1267 struct pid *req_pid = task_tgid(current);
1268
1269 /* Sanity check - PID values must match. Setting
1270 * pid to 0 is how auditd ends auditing. */
1271 if (new_pid && (new_pid != pid_vnr(req_pid)))
1272 return -EINVAL;
1273
1274 /* test the auditd connection */
1275 audit_replace(req_pid);
1276
1277 auditd_pid = auditd_pid_vnr();
1278 if (auditd_pid) {
1279 /* replacing a healthy auditd is not allowed */
1280 if (new_pid) {
1281 audit_log_config_change("audit_pid",
1282 new_pid, auditd_pid, 0);
1283 return -EEXIST;
1284 }
1285 /* only current auditd can unregister itself */
1286 if (pid_vnr(req_pid) != auditd_pid) {
1287 audit_log_config_change("audit_pid",
1288 new_pid, auditd_pid, 0);
1289 return -EACCES;
1290 }
1291 }
1292
1293 if (new_pid) {
1294 /* register a new auditd connection */
1295 err = auditd_set(req_pid,
1296 NETLINK_CB(skb).portid,
1297 sock_net(NETLINK_CB(skb).sk));
1298 if (audit_enabled != AUDIT_OFF)
1299 audit_log_config_change("audit_pid",
1300 new_pid,
1301 auditd_pid,
1302 err ? 0 : 1);
1303 if (err)
1304 return err;
1305
1306 /* try to process any backlog */
1307 wake_up_interruptible(&kauditd_wait);
1308 } else {
1309 if (audit_enabled != AUDIT_OFF)
1310 audit_log_config_change("audit_pid",
1311 new_pid,
1312 auditd_pid, 1);
1313
1314 /* unregister the auditd connection */
1315 auditd_reset(NULL);
1316 }
1317 }
1318 if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
1319 err = audit_set_rate_limit(s.rate_limit);
1320 if (err < 0)
1321 return err;
1322 }
1323 if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
1324 err = audit_set_backlog_limit(s.backlog_limit);
1325 if (err < 0)
1326 return err;
1327 }
1328 if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
1329 if (sizeof(s) > (size_t)nlh->nlmsg_len)
1330 return -EINVAL;
1331 if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
1332 return -EINVAL;
1333 err = audit_set_backlog_wait_time(s.backlog_wait_time);
1334 if (err < 0)
1335 return err;
1336 }
1337 if (s.mask == AUDIT_STATUS_LOST) {
1338 u32 lost = atomic_xchg(&audit_lost, 0);
1339
1340 audit_log_config_change("lost", 0, lost, 1);
1341 return lost;
1342 }
1343 if (s.mask == AUDIT_STATUS_BACKLOG_WAIT_TIME_ACTUAL) {
1344 u32 actual = atomic_xchg(&audit_backlog_wait_time_actual, 0);
1345
1346 audit_log_config_change("backlog_wait_time_actual", 0, actual, 1);
1347 return actual;
1348 }
1349 break;
1350 }
1351 case AUDIT_GET_FEATURE:
1352 err = audit_get_feature(skb);
1353 if (err)
1354 return err;
1355 break;
1356 case AUDIT_SET_FEATURE:
1357 if (data_len < sizeof(struct audit_features))
1358 return -EINVAL;
1359 err = audit_set_feature(data);
1360 if (err)
1361 return err;
1362 break;
1363 case AUDIT_USER:
1364 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1365 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1366 if (!audit_enabled && msg_type != AUDIT_USER_AVC)
1367 return 0;
1368 /* exit early if there isn't at least one character to print */
1369 if (data_len < 2)
1370 return -EINVAL;
1371
1372 err = audit_filter(msg_type, AUDIT_FILTER_USER);
1373 if (err == 1) { /* match or error */
1374 char *str = data;
1375
1376 err = 0;
1377 if (msg_type == AUDIT_USER_TTY) {
1378 err = tty_audit_push();
1379 if (err)
1380 break;
1381 }
1382 audit_log_user_recv_msg(&ab, msg_type);
1383 if (msg_type != AUDIT_USER_TTY) {
1384 /* ensure NULL termination */
1385 str[data_len - 1] = '\0';
1386 audit_log_format(ab, " msg='%.*s'",
1387 AUDIT_MESSAGE_TEXT_MAX,
1388 str);
1389 } else {
1390 audit_log_format(ab, " data=");
1391 if (str[data_len - 1] == '\0')
1392 data_len--;
1393 audit_log_n_untrustedstring(ab, str, data_len);
1394 }
1395 audit_log_end(ab);
1396 }
1397 break;
1398 case AUDIT_ADD_RULE:
1399 case AUDIT_DEL_RULE:
1400 if (data_len < sizeof(struct audit_rule_data))
1401 return -EINVAL;
1402 if (audit_enabled == AUDIT_LOCKED) {
1403 audit_log_common_recv_msg(audit_context(), &ab,
1404 AUDIT_CONFIG_CHANGE);
1405 audit_log_format(ab, " op=%s audit_enabled=%d res=0",
1406 msg_type == AUDIT_ADD_RULE ?
1407 "add_rule" : "remove_rule",
1408 audit_enabled);
1409 audit_log_end(ab);
1410 return -EPERM;
1411 }
1412 err = audit_rule_change(msg_type, seq, data, data_len);
1413 break;
1414 case AUDIT_LIST_RULES:
1415 err = audit_list_rules_send(skb, seq);
1416 break;
1417 case AUDIT_TRIM:
1418 audit_trim_trees();
1419 audit_log_common_recv_msg(audit_context(), &ab,
1420 AUDIT_CONFIG_CHANGE);
1421 audit_log_format(ab, " op=trim res=1");
1422 audit_log_end(ab);
1423 break;
1424 case AUDIT_MAKE_EQUIV: {
1425 void *bufp = data;
1426 u32 sizes[2];
1427 size_t msglen = data_len;
1428 char *old, *new;
1429
1430 err = -EINVAL;
1431 if (msglen < 2 * sizeof(u32))
1432 break;
1433 memcpy(sizes, bufp, 2 * sizeof(u32));
1434 bufp += 2 * sizeof(u32);
1435 msglen -= 2 * sizeof(u32);
1436 old = audit_unpack_string(&bufp, &msglen, sizes[0]);
1437 if (IS_ERR(old)) {
1438 err = PTR_ERR(old);
1439 break;
1440 }
1441 new = audit_unpack_string(&bufp, &msglen, sizes[1]);
1442 if (IS_ERR(new)) {
1443 err = PTR_ERR(new);
1444 kfree(old);
1445 break;
1446 }
1447 /* OK, here comes... */
1448 err = audit_tag_tree(old, new);
1449
1450 audit_log_common_recv_msg(audit_context(), &ab,
1451 AUDIT_CONFIG_CHANGE);
1452 audit_log_format(ab, " op=make_equiv old=");
1453 audit_log_untrustedstring(ab, old);
1454 audit_log_format(ab, " new=");
1455 audit_log_untrustedstring(ab, new);
1456 audit_log_format(ab, " res=%d", !err);
1457 audit_log_end(ab);
1458 kfree(old);
1459 kfree(new);
1460 break;
1461 }
1462 case AUDIT_SIGNAL_INFO:
1463 len = 0;
1464 if (audit_sig_sid) {
1465 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
1466 if (err)
1467 return err;
1468 }
1469 sig_data = kmalloc(struct_size(sig_data, ctx, len), GFP_KERNEL);
1470 if (!sig_data) {
1471 if (audit_sig_sid)
1472 security_release_secctx(ctx, len);
1473 return -ENOMEM;
1474 }
1475 sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
1476 sig_data->pid = audit_sig_pid;
1477 if (audit_sig_sid) {
1478 memcpy(sig_data->ctx, ctx, len);
1479 security_release_secctx(ctx, len);
1480 }
1481 audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
1482 sig_data, struct_size(sig_data, ctx, len));
1483 kfree(sig_data);
1484 break;
1485 case AUDIT_TTY_GET: {
1486 struct audit_tty_status s;
1487 unsigned int t;
1488
1489 t = READ_ONCE(current->signal->audit_tty);
1490 s.enabled = t & AUDIT_TTY_ENABLE;
1491 s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1492
1493 audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
1494 break;
1495 }
1496 case AUDIT_TTY_SET: {
1497 struct audit_tty_status s, old;
1498 struct audit_buffer *ab;
1499 unsigned int t;
1500
1501 memset(&s, 0, sizeof(s));
1502 /* guard against past and future API changes */
1503 memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
1504 /* check if new data is valid */
1505 if ((s.enabled != 0 && s.enabled != 1) ||
1506 (s.log_passwd != 0 && s.log_passwd != 1))
1507 err = -EINVAL;
1508
1509 if (err)
1510 t = READ_ONCE(current->signal->audit_tty);
1511 else {
1512 t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD);
1513 t = xchg(&current->signal->audit_tty, t);
1514 }
1515 old.enabled = t & AUDIT_TTY_ENABLE;
1516 old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1517
1518 audit_log_common_recv_msg(audit_context(), &ab,
1519 AUDIT_CONFIG_CHANGE);
1520 audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
1521 " old-log_passwd=%d new-log_passwd=%d res=%d",
1522 old.enabled, s.enabled, old.log_passwd,
1523 s.log_passwd, !err);
1524 audit_log_end(ab);
1525 break;
1526 }
1527 default:
1528 err = -EINVAL;
1529 break;
1530 }
1531
1532 return err < 0 ? err : 0;
1533}
1534
1535/**
1536 * audit_receive - receive messages from a netlink control socket
1537 * @skb: the message buffer
1538 *
1539 * Parse the provided skb and deal with any messages that may be present,
1540 * malformed skbs are discarded.
1541 */
1542static void audit_receive(struct sk_buff *skb)
1543{
1544 struct nlmsghdr *nlh;
1545 /*
1546 * len MUST be signed for nlmsg_next to be able to dec it below 0
1547 * if the nlmsg_len was not aligned
1548 */
1549 int len;
1550 int err;
1551
1552 nlh = nlmsg_hdr(skb);
1553 len = skb->len;
1554
1555 audit_ctl_lock();
1556 while (nlmsg_ok(nlh, len)) {
1557 err = audit_receive_msg(skb, nlh);
1558 /* if err or if this message says it wants a response */
1559 if (err || (nlh->nlmsg_flags & NLM_F_ACK))
1560 netlink_ack(skb, nlh, err, NULL);
1561
1562 nlh = nlmsg_next(nlh, &len);
1563 }
1564 audit_ctl_unlock();
1565
1566 /* can't block with the ctrl lock, so penalize the sender now */
1567 if (audit_backlog_limit &&
1568 (skb_queue_len(&audit_queue) > audit_backlog_limit)) {
1569 DECLARE_WAITQUEUE(wait, current);
1570
1571 /* wake kauditd to try and flush the queue */
1572 wake_up_interruptible(&kauditd_wait);
1573
1574 add_wait_queue_exclusive(&audit_backlog_wait, &wait);
1575 set_current_state(TASK_UNINTERRUPTIBLE);
1576 schedule_timeout(audit_backlog_wait_time);
1577 remove_wait_queue(&audit_backlog_wait, &wait);
1578 }
1579}
1580
1581/* Log information about who is connecting to the audit multicast socket */
1582static void audit_log_multicast(int group, const char *op, int err)
1583{
1584 const struct cred *cred;
1585 struct tty_struct *tty;
1586 char comm[sizeof(current->comm)];
1587 struct audit_buffer *ab;
1588
1589 if (!audit_enabled)
1590 return;
1591
1592 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_EVENT_LISTENER);
1593 if (!ab)
1594 return;
1595
1596 cred = current_cred();
1597 tty = audit_get_tty();
1598 audit_log_format(ab, "pid=%u uid=%u auid=%u tty=%s ses=%u",
1599 task_pid_nr(current),
1600 from_kuid(&init_user_ns, cred->uid),
1601 from_kuid(&init_user_ns, audit_get_loginuid(current)),
1602 tty ? tty_name(tty) : "(none)",
1603 audit_get_sessionid(current));
1604 audit_put_tty(tty);
1605 audit_log_task_context(ab); /* subj= */
1606 audit_log_format(ab, " comm=");
1607 audit_log_untrustedstring(ab, get_task_comm(comm, current));
1608 audit_log_d_path_exe(ab, current->mm); /* exe= */
1609 audit_log_format(ab, " nl-mcgrp=%d op=%s res=%d", group, op, !err);
1610 audit_log_end(ab);
1611}
1612
1613/* Run custom bind function on netlink socket group connect or bind requests. */
1614static int audit_multicast_bind(struct net *net, int group)
1615{
1616 int err = 0;
1617
1618 if (!capable(CAP_AUDIT_READ))
1619 err = -EPERM;
1620 audit_log_multicast(group, "connect", err);
1621 return err;
1622}
1623
1624static void audit_multicast_unbind(struct net *net, int group)
1625{
1626 audit_log_multicast(group, "disconnect", 0);
1627}
1628
1629static int __net_init audit_net_init(struct net *net)
1630{
1631 struct netlink_kernel_cfg cfg = {
1632 .input = audit_receive,
1633 .bind = audit_multicast_bind,
1634 .unbind = audit_multicast_unbind,
1635 .flags = NL_CFG_F_NONROOT_RECV,
1636 .groups = AUDIT_NLGRP_MAX,
1637 };
1638
1639 struct audit_net *aunet = net_generic(net, audit_net_id);
1640
1641 aunet->sk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
1642 if (aunet->sk == NULL) {
1643 audit_panic("cannot initialize netlink socket in namespace");
1644 return -ENOMEM;
1645 }
1646 /* limit the timeout in case auditd is blocked/stopped */
1647 aunet->sk->sk_sndtimeo = HZ / 10;
1648
1649 return 0;
1650}
1651
1652static void __net_exit audit_net_exit(struct net *net)
1653{
1654 struct audit_net *aunet = net_generic(net, audit_net_id);
1655
1656 /* NOTE: you would think that we would want to check the auditd
1657 * connection and potentially reset it here if it lives in this
1658 * namespace, but since the auditd connection tracking struct holds a
1659 * reference to this namespace (see auditd_set()) we are only ever
1660 * going to get here after that connection has been released */
1661
1662 netlink_kernel_release(aunet->sk);
1663}
1664
1665static struct pernet_operations audit_net_ops __net_initdata = {
1666 .init = audit_net_init,
1667 .exit = audit_net_exit,
1668 .id = &audit_net_id,
1669 .size = sizeof(struct audit_net),
1670};
1671
1672/* Initialize audit support at boot time. */
1673static int __init audit_init(void)
1674{
1675 int i;
1676
1677 if (audit_initialized == AUDIT_DISABLED)
1678 return 0;
1679
1680 audit_buffer_cache = kmem_cache_create("audit_buffer",
1681 sizeof(struct audit_buffer),
1682 0, SLAB_PANIC, NULL);
1683
1684 skb_queue_head_init(&audit_queue);
1685 skb_queue_head_init(&audit_retry_queue);
1686 skb_queue_head_init(&audit_hold_queue);
1687
1688 for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
1689 INIT_LIST_HEAD(&audit_inode_hash[i]);
1690
1691 mutex_init(&audit_cmd_mutex.lock);
1692 audit_cmd_mutex.owner = NULL;
1693
1694 pr_info("initializing netlink subsys (%s)\n",
1695 audit_default ? "enabled" : "disabled");
1696 register_pernet_subsys(&audit_net_ops);
1697
1698 audit_initialized = AUDIT_INITIALIZED;
1699
1700 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
1701 if (IS_ERR(kauditd_task)) {
1702 int err = PTR_ERR(kauditd_task);
1703 panic("audit: failed to start the kauditd thread (%d)\n", err);
1704 }
1705
1706 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL,
1707 "state=initialized audit_enabled=%u res=1",
1708 audit_enabled);
1709
1710 return 0;
1711}
1712postcore_initcall(audit_init);
1713
1714/*
1715 * Process kernel command-line parameter at boot time.
1716 * audit={0|off} or audit={1|on}.
1717 */
1718static int __init audit_enable(char *str)
1719{
1720 if (!strcasecmp(str, "off") || !strcmp(str, "0"))
1721 audit_default = AUDIT_OFF;
1722 else if (!strcasecmp(str, "on") || !strcmp(str, "1"))
1723 audit_default = AUDIT_ON;
1724 else {
1725 pr_err("audit: invalid 'audit' parameter value (%s)\n", str);
1726 audit_default = AUDIT_ON;
1727 }
1728
1729 if (audit_default == AUDIT_OFF)
1730 audit_initialized = AUDIT_DISABLED;
1731 if (audit_set_enabled(audit_default))
1732 pr_err("audit: error setting audit state (%d)\n",
1733 audit_default);
1734
1735 pr_info("%s\n", audit_default ?
1736 "enabled (after initialization)" : "disabled (until reboot)");
1737
1738 return 1;
1739}
1740__setup("audit=", audit_enable);
1741
1742/* Process kernel command-line parameter at boot time.
1743 * audit_backlog_limit=<n> */
1744static int __init audit_backlog_limit_set(char *str)
1745{
1746 u32 audit_backlog_limit_arg;
1747
1748 pr_info("audit_backlog_limit: ");
1749 if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
1750 pr_cont("using default of %u, unable to parse %s\n",
1751 audit_backlog_limit, str);
1752 return 1;
1753 }
1754
1755 audit_backlog_limit = audit_backlog_limit_arg;
1756 pr_cont("%d\n", audit_backlog_limit);
1757
1758 return 1;
1759}
1760__setup("audit_backlog_limit=", audit_backlog_limit_set);
1761
1762static void audit_buffer_free(struct audit_buffer *ab)
1763{
1764 if (!ab)
1765 return;
1766
1767 kfree_skb(ab->skb);
1768 kmem_cache_free(audit_buffer_cache, ab);
1769}
1770
1771static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx,
1772 gfp_t gfp_mask, int type)
1773{
1774 struct audit_buffer *ab;
1775
1776 ab = kmem_cache_alloc(audit_buffer_cache, gfp_mask);
1777 if (!ab)
1778 return NULL;
1779
1780 ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
1781 if (!ab->skb)
1782 goto err;
1783 if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0))
1784 goto err;
1785
1786 ab->ctx = ctx;
1787 ab->gfp_mask = gfp_mask;
1788
1789 return ab;
1790
1791err:
1792 audit_buffer_free(ab);
1793 return NULL;
1794}
1795
1796/**
1797 * audit_serial - compute a serial number for the audit record
1798 *
1799 * Compute a serial number for the audit record. Audit records are
1800 * written to user-space as soon as they are generated, so a complete
1801 * audit record may be written in several pieces. The timestamp of the
1802 * record and this serial number are used by the user-space tools to
1803 * determine which pieces belong to the same audit record. The
1804 * (timestamp,serial) tuple is unique for each syscall and is live from
1805 * syscall entry to syscall exit.
1806 *
1807 * NOTE: Another possibility is to store the formatted records off the
1808 * audit context (for those records that have a context), and emit them
1809 * all at syscall exit. However, this could delay the reporting of
1810 * significant errors until syscall exit (or never, if the system
1811 * halts).
1812 */
1813unsigned int audit_serial(void)
1814{
1815 static atomic_t serial = ATOMIC_INIT(0);
1816
1817 return atomic_inc_return(&serial);
1818}
1819
1820static inline void audit_get_stamp(struct audit_context *ctx,
1821 struct timespec64 *t, unsigned int *serial)
1822{
1823 if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
1824 ktime_get_coarse_real_ts64(t);
1825 *serial = audit_serial();
1826 }
1827}
1828
1829/**
1830 * audit_log_start - obtain an audit buffer
1831 * @ctx: audit_context (may be NULL)
1832 * @gfp_mask: type of allocation
1833 * @type: audit message type
1834 *
1835 * Returns audit_buffer pointer on success or NULL on error.
1836 *
1837 * Obtain an audit buffer. This routine does locking to obtain the
1838 * audit buffer, but then no locking is required for calls to
1839 * audit_log_*format. If the task (ctx) is a task that is currently in a
1840 * syscall, then the syscall is marked as auditable and an audit record
1841 * will be written at syscall exit. If there is no associated task, then
1842 * task context (ctx) should be NULL.
1843 */
1844struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1845 int type)
1846{
1847 struct audit_buffer *ab;
1848 struct timespec64 t;
1849 unsigned int serial;
1850
1851 if (audit_initialized != AUDIT_INITIALIZED)
1852 return NULL;
1853
1854 if (unlikely(!audit_filter(type, AUDIT_FILTER_EXCLUDE)))
1855 return NULL;
1856
1857 /* NOTE: don't ever fail/sleep on these two conditions:
1858 * 1. auditd generated record - since we need auditd to drain the
1859 * queue; also, when we are checking for auditd, compare PIDs using
1860 * task_tgid_vnr() since auditd_pid is set in audit_receive_msg()
1861 * using a PID anchored in the caller's namespace
1862 * 2. generator holding the audit_cmd_mutex - we don't want to block
1863 * while holding the mutex, although we do penalize the sender
1864 * later in audit_receive() when it is safe to block
1865 */
1866 if (!(auditd_test_task(current) || audit_ctl_owner_current())) {
1867 long stime = audit_backlog_wait_time;
1868
1869 while (audit_backlog_limit &&
1870 (skb_queue_len(&audit_queue) > audit_backlog_limit)) {
1871 /* wake kauditd to try and flush the queue */
1872 wake_up_interruptible(&kauditd_wait);
1873
1874 /* sleep if we are allowed and we haven't exhausted our
1875 * backlog wait limit */
1876 if (gfpflags_allow_blocking(gfp_mask) && (stime > 0)) {
1877 long rtime = stime;
1878
1879 DECLARE_WAITQUEUE(wait, current);
1880
1881 add_wait_queue_exclusive(&audit_backlog_wait,
1882 &wait);
1883 set_current_state(TASK_UNINTERRUPTIBLE);
1884 stime = schedule_timeout(rtime);
1885 atomic_add(rtime - stime, &audit_backlog_wait_time_actual);
1886 remove_wait_queue(&audit_backlog_wait, &wait);
1887 } else {
1888 if (audit_rate_check() && printk_ratelimit())
1889 pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
1890 skb_queue_len(&audit_queue),
1891 audit_backlog_limit);
1892 audit_log_lost("backlog limit exceeded");
1893 return NULL;
1894 }
1895 }
1896 }
1897
1898 ab = audit_buffer_alloc(ctx, gfp_mask, type);
1899 if (!ab) {
1900 audit_log_lost("out of memory in audit_log_start");
1901 return NULL;
1902 }
1903
1904 audit_get_stamp(ab->ctx, &t, &serial);
1905 /* cancel dummy context to enable supporting records */
1906 if (ctx)
1907 ctx->dummy = 0;
1908 audit_log_format(ab, "audit(%llu.%03lu:%u): ",
1909 (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
1910
1911 return ab;
1912}
1913
1914/**
1915 * audit_expand - expand skb in the audit buffer
1916 * @ab: audit_buffer
1917 * @extra: space to add at tail of the skb
1918 *
1919 * Returns 0 (no space) on failed expansion, or available space if
1920 * successful.
1921 */
1922static inline int audit_expand(struct audit_buffer *ab, int extra)
1923{
1924 struct sk_buff *skb = ab->skb;
1925 int oldtail = skb_tailroom(skb);
1926 int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1927 int newtail = skb_tailroom(skb);
1928
1929 if (ret < 0) {
1930 audit_log_lost("out of memory in audit_expand");
1931 return 0;
1932 }
1933
1934 skb->truesize += newtail - oldtail;
1935 return newtail;
1936}
1937
1938/*
1939 * Format an audit message into the audit buffer. If there isn't enough
1940 * room in the audit buffer, more room will be allocated and vsnprint
1941 * will be called a second time. Currently, we assume that a printk
1942 * can't format message larger than 1024 bytes, so we don't either.
1943 */
1944static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1945 va_list args)
1946{
1947 int len, avail;
1948 struct sk_buff *skb;
1949 va_list args2;
1950
1951 if (!ab)
1952 return;
1953
1954 BUG_ON(!ab->skb);
1955 skb = ab->skb;
1956 avail = skb_tailroom(skb);
1957 if (avail == 0) {
1958 avail = audit_expand(ab, AUDIT_BUFSIZ);
1959 if (!avail)
1960 goto out;
1961 }
1962 va_copy(args2, args);
1963 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1964 if (len >= avail) {
1965 /* The printk buffer is 1024 bytes long, so if we get
1966 * here and AUDIT_BUFSIZ is at least 1024, then we can
1967 * log everything that printk could have logged. */
1968 avail = audit_expand(ab,
1969 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1970 if (!avail)
1971 goto out_va_end;
1972 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1973 }
1974 if (len > 0)
1975 skb_put(skb, len);
1976out_va_end:
1977 va_end(args2);
1978out:
1979 return;
1980}
1981
1982/**
1983 * audit_log_format - format a message into the audit buffer.
1984 * @ab: audit_buffer
1985 * @fmt: format string
1986 * @...: optional parameters matching @fmt string
1987 *
1988 * All the work is done in audit_log_vformat.
1989 */
1990void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1991{
1992 va_list args;
1993
1994 if (!ab)
1995 return;
1996 va_start(args, fmt);
1997 audit_log_vformat(ab, fmt, args);
1998 va_end(args);
1999}
2000
2001/**
2002 * audit_log_n_hex - convert a buffer to hex and append it to the audit skb
2003 * @ab: the audit_buffer
2004 * @buf: buffer to convert to hex
2005 * @len: length of @buf to be converted
2006 *
2007 * No return value; failure to expand is silently ignored.
2008 *
2009 * This function will take the passed buf and convert it into a string of
2010 * ascii hex digits. The new string is placed onto the skb.
2011 */
2012void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
2013 size_t len)
2014{
2015 int i, avail, new_len;
2016 unsigned char *ptr;
2017 struct sk_buff *skb;
2018
2019 if (!ab)
2020 return;
2021
2022 BUG_ON(!ab->skb);
2023 skb = ab->skb;
2024 avail = skb_tailroom(skb);
2025 new_len = len<<1;
2026 if (new_len >= avail) {
2027 /* Round the buffer request up to the next multiple */
2028 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
2029 avail = audit_expand(ab, new_len);
2030 if (!avail)
2031 return;
2032 }
2033
2034 ptr = skb_tail_pointer(skb);
2035 for (i = 0; i < len; i++)
2036 ptr = hex_byte_pack_upper(ptr, buf[i]);
2037 *ptr = 0;
2038 skb_put(skb, len << 1); /* new string is twice the old string */
2039}
2040
2041/*
2042 * Format a string of no more than slen characters into the audit buffer,
2043 * enclosed in quote marks.
2044 */
2045void audit_log_n_string(struct audit_buffer *ab, const char *string,
2046 size_t slen)
2047{
2048 int avail, new_len;
2049 unsigned char *ptr;
2050 struct sk_buff *skb;
2051
2052 if (!ab)
2053 return;
2054
2055 BUG_ON(!ab->skb);
2056 skb = ab->skb;
2057 avail = skb_tailroom(skb);
2058 new_len = slen + 3; /* enclosing quotes + null terminator */
2059 if (new_len > avail) {
2060 avail = audit_expand(ab, new_len);
2061 if (!avail)
2062 return;
2063 }
2064 ptr = skb_tail_pointer(skb);
2065 *ptr++ = '"';
2066 memcpy(ptr, string, slen);
2067 ptr += slen;
2068 *ptr++ = '"';
2069 *ptr = 0;
2070 skb_put(skb, slen + 2); /* don't include null terminator */
2071}
2072
2073/**
2074 * audit_string_contains_control - does a string need to be logged in hex
2075 * @string: string to be checked
2076 * @len: max length of the string to check
2077 */
2078bool audit_string_contains_control(const char *string, size_t len)
2079{
2080 const unsigned char *p;
2081 for (p = string; p < (const unsigned char *)string + len; p++) {
2082 if (*p == '"' || *p < 0x21 || *p > 0x7e)
2083 return true;
2084 }
2085 return false;
2086}
2087
2088/**
2089 * audit_log_n_untrustedstring - log a string that may contain random characters
2090 * @ab: audit_buffer
2091 * @len: length of string (not including trailing null)
2092 * @string: string to be logged
2093 *
2094 * This code will escape a string that is passed to it if the string
2095 * contains a control character, unprintable character, double quote mark,
2096 * or a space. Unescaped strings will start and end with a double quote mark.
2097 * Strings that are escaped are printed in hex (2 digits per char).
2098 *
2099 * The caller specifies the number of characters in the string to log, which may
2100 * or may not be the entire string.
2101 */
2102void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
2103 size_t len)
2104{
2105 if (audit_string_contains_control(string, len))
2106 audit_log_n_hex(ab, string, len);
2107 else
2108 audit_log_n_string(ab, string, len);
2109}
2110
2111/**
2112 * audit_log_untrustedstring - log a string that may contain random characters
2113 * @ab: audit_buffer
2114 * @string: string to be logged
2115 *
2116 * Same as audit_log_n_untrustedstring(), except that strlen is used to
2117 * determine string length.
2118 */
2119void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
2120{
2121 audit_log_n_untrustedstring(ab, string, strlen(string));
2122}
2123
2124/* This is a helper-function to print the escaped d_path */
2125void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
2126 const struct path *path)
2127{
2128 char *p, *pathname;
2129
2130 if (prefix)
2131 audit_log_format(ab, "%s", prefix);
2132
2133 /* We will allow 11 spaces for ' (deleted)' to be appended */
2134 pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
2135 if (!pathname) {
2136 audit_log_format(ab, "\"<no_memory>\"");
2137 return;
2138 }
2139 p = d_path(path, pathname, PATH_MAX+11);
2140 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
2141 /* FIXME: can we save some information here? */
2142 audit_log_format(ab, "\"<too_long>\"");
2143 } else
2144 audit_log_untrustedstring(ab, p);
2145 kfree(pathname);
2146}
2147
2148void audit_log_session_info(struct audit_buffer *ab)
2149{
2150 unsigned int sessionid = audit_get_sessionid(current);
2151 uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
2152
2153 audit_log_format(ab, "auid=%u ses=%u", auid, sessionid);
2154}
2155
2156void audit_log_key(struct audit_buffer *ab, char *key)
2157{
2158 audit_log_format(ab, " key=");
2159 if (key)
2160 audit_log_untrustedstring(ab, key);
2161 else
2162 audit_log_format(ab, "(null)");
2163}
2164
2165int audit_log_task_context(struct audit_buffer *ab)
2166{
2167 char *ctx = NULL;
2168 unsigned len;
2169 int error;
2170 u32 sid;
2171
2172 security_current_getsecid_subj(&sid);
2173 if (!sid)
2174 return 0;
2175
2176 error = security_secid_to_secctx(sid, &ctx, &len);
2177 if (error) {
2178 if (error != -EINVAL)
2179 goto error_path;
2180 return 0;
2181 }
2182
2183 audit_log_format(ab, " subj=%s", ctx);
2184 security_release_secctx(ctx, len);
2185 return 0;
2186
2187error_path:
2188 audit_panic("error in audit_log_task_context");
2189 return error;
2190}
2191EXPORT_SYMBOL(audit_log_task_context);
2192
2193void audit_log_d_path_exe(struct audit_buffer *ab,
2194 struct mm_struct *mm)
2195{
2196 struct file *exe_file;
2197
2198 if (!mm)
2199 goto out_null;
2200
2201 exe_file = get_mm_exe_file(mm);
2202 if (!exe_file)
2203 goto out_null;
2204
2205 audit_log_d_path(ab, " exe=", &exe_file->f_path);
2206 fput(exe_file);
2207 return;
2208out_null:
2209 audit_log_format(ab, " exe=(null)");
2210}
2211
2212struct tty_struct *audit_get_tty(void)
2213{
2214 struct tty_struct *tty = NULL;
2215 unsigned long flags;
2216
2217 spin_lock_irqsave(&current->sighand->siglock, flags);
2218 if (current->signal)
2219 tty = tty_kref_get(current->signal->tty);
2220 spin_unlock_irqrestore(&current->sighand->siglock, flags);
2221 return tty;
2222}
2223
2224void audit_put_tty(struct tty_struct *tty)
2225{
2226 tty_kref_put(tty);
2227}
2228
2229void audit_log_task_info(struct audit_buffer *ab)
2230{
2231 const struct cred *cred;
2232 char comm[sizeof(current->comm)];
2233 struct tty_struct *tty;
2234
2235 if (!ab)
2236 return;
2237
2238 cred = current_cred();
2239 tty = audit_get_tty();
2240 audit_log_format(ab,
2241 " ppid=%d pid=%d auid=%u uid=%u gid=%u"
2242 " euid=%u suid=%u fsuid=%u"
2243 " egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
2244 task_ppid_nr(current),
2245 task_tgid_nr(current),
2246 from_kuid(&init_user_ns, audit_get_loginuid(current)),
2247 from_kuid(&init_user_ns, cred->uid),
2248 from_kgid(&init_user_ns, cred->gid),
2249 from_kuid(&init_user_ns, cred->euid),
2250 from_kuid(&init_user_ns, cred->suid),
2251 from_kuid(&init_user_ns, cred->fsuid),
2252 from_kgid(&init_user_ns, cred->egid),
2253 from_kgid(&init_user_ns, cred->sgid),
2254 from_kgid(&init_user_ns, cred->fsgid),
2255 tty ? tty_name(tty) : "(none)",
2256 audit_get_sessionid(current));
2257 audit_put_tty(tty);
2258 audit_log_format(ab, " comm=");
2259 audit_log_untrustedstring(ab, get_task_comm(comm, current));
2260 audit_log_d_path_exe(ab, current->mm);
2261 audit_log_task_context(ab);
2262}
2263EXPORT_SYMBOL(audit_log_task_info);
2264
2265/**
2266 * audit_log_path_denied - report a path restriction denial
2267 * @type: audit message type (AUDIT_ANOM_LINK, AUDIT_ANOM_CREAT, etc)
2268 * @operation: specific operation name
2269 */
2270void audit_log_path_denied(int type, const char *operation)
2271{
2272 struct audit_buffer *ab;
2273
2274 if (!audit_enabled || audit_dummy_context())
2275 return;
2276
2277 /* Generate log with subject, operation, outcome. */
2278 ab = audit_log_start(audit_context(), GFP_KERNEL, type);
2279 if (!ab)
2280 return;
2281 audit_log_format(ab, "op=%s", operation);
2282 audit_log_task_info(ab);
2283 audit_log_format(ab, " res=0");
2284 audit_log_end(ab);
2285}
2286
2287/* global counter which is incremented every time something logs in */
2288static atomic_t session_id = ATOMIC_INIT(0);
2289
2290static int audit_set_loginuid_perm(kuid_t loginuid)
2291{
2292 /* if we are unset, we don't need privs */
2293 if (!audit_loginuid_set(current))
2294 return 0;
2295 /* if AUDIT_FEATURE_LOGINUID_IMMUTABLE means never ever allow a change*/
2296 if (is_audit_feature_set(AUDIT_FEATURE_LOGINUID_IMMUTABLE))
2297 return -EPERM;
2298 /* it is set, you need permission */
2299 if (!capable(CAP_AUDIT_CONTROL))
2300 return -EPERM;
2301 /* reject if this is not an unset and we don't allow that */
2302 if (is_audit_feature_set(AUDIT_FEATURE_ONLY_UNSET_LOGINUID)
2303 && uid_valid(loginuid))
2304 return -EPERM;
2305 return 0;
2306}
2307
2308static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
2309 unsigned int oldsessionid,
2310 unsigned int sessionid, int rc)
2311{
2312 struct audit_buffer *ab;
2313 uid_t uid, oldloginuid, loginuid;
2314 struct tty_struct *tty;
2315
2316 if (!audit_enabled)
2317 return;
2318
2319 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_LOGIN);
2320 if (!ab)
2321 return;
2322
2323 uid = from_kuid(&init_user_ns, task_uid(current));
2324 oldloginuid = from_kuid(&init_user_ns, koldloginuid);
2325 loginuid = from_kuid(&init_user_ns, kloginuid);
2326 tty = audit_get_tty();
2327
2328 audit_log_format(ab, "pid=%d uid=%u", task_tgid_nr(current), uid);
2329 audit_log_task_context(ab);
2330 audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",
2331 oldloginuid, loginuid, tty ? tty_name(tty) : "(none)",
2332 oldsessionid, sessionid, !rc);
2333 audit_put_tty(tty);
2334 audit_log_end(ab);
2335}
2336
2337/**
2338 * audit_set_loginuid - set current task's loginuid
2339 * @loginuid: loginuid value
2340 *
2341 * Returns 0.
2342 *
2343 * Called (set) from fs/proc/base.c::proc_loginuid_write().
2344 */
2345int audit_set_loginuid(kuid_t loginuid)
2346{
2347 unsigned int oldsessionid, sessionid = AUDIT_SID_UNSET;
2348 kuid_t oldloginuid;
2349 int rc;
2350
2351 oldloginuid = audit_get_loginuid(current);
2352 oldsessionid = audit_get_sessionid(current);
2353
2354 rc = audit_set_loginuid_perm(loginuid);
2355 if (rc)
2356 goto out;
2357
2358 /* are we setting or clearing? */
2359 if (uid_valid(loginuid)) {
2360 sessionid = (unsigned int)atomic_inc_return(&session_id);
2361 if (unlikely(sessionid == AUDIT_SID_UNSET))
2362 sessionid = (unsigned int)atomic_inc_return(&session_id);
2363 }
2364
2365 current->sessionid = sessionid;
2366 current->loginuid = loginuid;
2367out:
2368 audit_log_set_loginuid(oldloginuid, loginuid, oldsessionid, sessionid, rc);
2369 return rc;
2370}
2371
2372/**
2373 * audit_signal_info - record signal info for shutting down audit subsystem
2374 * @sig: signal value
2375 * @t: task being signaled
2376 *
2377 * If the audit subsystem is being terminated, record the task (pid)
2378 * and uid that is doing that.
2379 */
2380int audit_signal_info(int sig, struct task_struct *t)
2381{
2382 kuid_t uid = current_uid(), auid;
2383
2384 if (auditd_test_task(t) &&
2385 (sig == SIGTERM || sig == SIGHUP ||
2386 sig == SIGUSR1 || sig == SIGUSR2)) {
2387 audit_sig_pid = task_tgid_nr(current);
2388 auid = audit_get_loginuid(current);
2389 if (uid_valid(auid))
2390 audit_sig_uid = auid;
2391 else
2392 audit_sig_uid = uid;
2393 security_current_getsecid_subj(&audit_sig_sid);
2394 }
2395
2396 return audit_signal_info_syscall(t);
2397}
2398
2399/**
2400 * audit_log_end - end one audit record
2401 * @ab: the audit_buffer
2402 *
2403 * We can not do a netlink send inside an irq context because it blocks (last
2404 * arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a
2405 * queue and a kthread is scheduled to remove them from the queue outside the
2406 * irq context. May be called in any context.
2407 */
2408void audit_log_end(struct audit_buffer *ab)
2409{
2410 struct sk_buff *skb;
2411 struct nlmsghdr *nlh;
2412
2413 if (!ab)
2414 return;
2415
2416 if (audit_rate_check()) {
2417 skb = ab->skb;
2418 ab->skb = NULL;
2419
2420 /* setup the netlink header, see the comments in
2421 * kauditd_send_multicast_skb() for length quirks */
2422 nlh = nlmsg_hdr(skb);
2423 nlh->nlmsg_len = skb->len - NLMSG_HDRLEN;
2424
2425 /* queue the netlink packet and poke the kauditd thread */
2426 skb_queue_tail(&audit_queue, skb);
2427 wake_up_interruptible(&kauditd_wait);
2428 } else
2429 audit_log_lost("rate limit exceeded");
2430
2431 audit_buffer_free(ab);
2432}
2433
2434/**
2435 * audit_log - Log an audit record
2436 * @ctx: audit context
2437 * @gfp_mask: type of allocation
2438 * @type: audit message type
2439 * @fmt: format string to use
2440 * @...: variable parameters matching the format string
2441 *
2442 * This is a convenience function that calls audit_log_start,
2443 * audit_log_vformat, and audit_log_end. It may be called
2444 * in any context.
2445 */
2446void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
2447 const char *fmt, ...)
2448{
2449 struct audit_buffer *ab;
2450 va_list args;
2451
2452 ab = audit_log_start(ctx, gfp_mask, type);
2453 if (ab) {
2454 va_start(args, fmt);
2455 audit_log_vformat(ab, fmt, args);
2456 va_end(args);
2457 audit_log_end(ab);
2458 }
2459}
2460
2461EXPORT_SYMBOL(audit_log_start);
2462EXPORT_SYMBOL(audit_log_end);
2463EXPORT_SYMBOL(audit_log_format);
2464EXPORT_SYMBOL(audit_log);