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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 * Example user-space utilities: http://people.redhat.com/sgrubb/audit/
42 */
43
44#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
45
46#include <linux/init.h>
47#include <asm/types.h>
48#include <linux/atomic.h>
49#include <linux/mm.h>
50#include <linux/export.h>
51#include <linux/slab.h>
52#include <linux/err.h>
53#include <linux/kthread.h>
54#include <linux/kernel.h>
55#include <linux/syscalls.h>
56
57#include <linux/audit.h>
58
59#include <net/sock.h>
60#include <net/netlink.h>
61#include <linux/skbuff.h>
62#ifdef CONFIG_SECURITY
63#include <linux/security.h>
64#endif
65#include <linux/freezer.h>
66#include <linux/tty.h>
67#include <linux/pid_namespace.h>
68#include <net/netns/generic.h>
69
70#include "audit.h"
71
72/* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
73 * (Initialization happens after skb_init is called.) */
74#define AUDIT_DISABLED -1
75#define AUDIT_UNINITIALIZED 0
76#define AUDIT_INITIALIZED 1
77static int audit_initialized;
78
79#define AUDIT_OFF 0
80#define AUDIT_ON 1
81#define AUDIT_LOCKED 2
82u32 audit_enabled;
83u32 audit_ever_enabled;
84
85EXPORT_SYMBOL_GPL(audit_enabled);
86
87/* Default state when kernel boots without any parameters. */
88static u32 audit_default;
89
90/* If auditing cannot proceed, audit_failure selects what happens. */
91static u32 audit_failure = AUDIT_FAIL_PRINTK;
92
93/*
94 * If audit records are to be written to the netlink socket, audit_pid
95 * contains the pid of the auditd process and audit_nlk_portid contains
96 * the portid to use to send netlink messages to that process.
97 */
98int audit_pid;
99static __u32 audit_nlk_portid;
100
101/* If audit_rate_limit is non-zero, limit the rate of sending audit records
102 * to that number per second. This prevents DoS attacks, but results in
103 * audit records being dropped. */
104static u32 audit_rate_limit;
105
106/* Number of outstanding audit_buffers allowed.
107 * When set to zero, this means unlimited. */
108static u32 audit_backlog_limit = 64;
109#define AUDIT_BACKLOG_WAIT_TIME (60 * HZ)
110static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
111static u32 audit_backlog_wait_overflow = 0;
112
113/* The identity of the user shutting down the audit system. */
114kuid_t audit_sig_uid = INVALID_UID;
115pid_t audit_sig_pid = -1;
116u32 audit_sig_sid = 0;
117
118/* Records can be lost in several ways:
119 0) [suppressed in audit_alloc]
120 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
121 2) out of memory in audit_log_move [alloc_skb]
122 3) suppressed due to audit_rate_limit
123 4) suppressed due to audit_backlog_limit
124*/
125static atomic_t audit_lost = ATOMIC_INIT(0);
126
127/* The netlink socket. */
128static struct sock *audit_sock;
129int audit_net_id;
130
131/* Hash for inode-based rules */
132struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
133
134/* The audit_freelist is a list of pre-allocated audit buffers (if more
135 * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
136 * being placed on the freelist). */
137static DEFINE_SPINLOCK(audit_freelist_lock);
138static int audit_freelist_count;
139static LIST_HEAD(audit_freelist);
140
141static struct sk_buff_head audit_skb_queue;
142/* queue of skbs to send to auditd when/if it comes back */
143static struct sk_buff_head audit_skb_hold_queue;
144static struct task_struct *kauditd_task;
145static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
146static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
147
148static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION,
149 .mask = -1,
150 .features = 0,
151 .lock = 0,};
152
153static char *audit_feature_names[2] = {
154 "only_unset_loginuid",
155 "loginuid_immutable",
156};
157
158
159/* Serialize requests from userspace. */
160DEFINE_MUTEX(audit_cmd_mutex);
161
162/* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
163 * audit records. Since printk uses a 1024 byte buffer, this buffer
164 * should be at least that large. */
165#define AUDIT_BUFSIZ 1024
166
167/* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the
168 * audit_freelist. Doing so eliminates many kmalloc/kfree calls. */
169#define AUDIT_MAXFREE (2*NR_CPUS)
170
171/* The audit_buffer is used when formatting an audit record. The caller
172 * locks briefly to get the record off the freelist or to allocate the
173 * buffer, and locks briefly to send the buffer to the netlink layer or
174 * to place it on a transmit queue. Multiple audit_buffers can be in
175 * use simultaneously. */
176struct audit_buffer {
177 struct list_head list;
178 struct sk_buff *skb; /* formatted skb ready to send */
179 struct audit_context *ctx; /* NULL or associated context */
180 gfp_t gfp_mask;
181};
182
183struct audit_reply {
184 __u32 portid;
185 struct net *net;
186 struct sk_buff *skb;
187};
188
189static void audit_set_portid(struct audit_buffer *ab, __u32 portid)
190{
191 if (ab) {
192 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
193 nlh->nlmsg_pid = portid;
194 }
195}
196
197void audit_panic(const char *message)
198{
199 switch (audit_failure) {
200 case AUDIT_FAIL_SILENT:
201 break;
202 case AUDIT_FAIL_PRINTK:
203 if (printk_ratelimit())
204 pr_err("%s\n", message);
205 break;
206 case AUDIT_FAIL_PANIC:
207 /* test audit_pid since printk is always losey, why bother? */
208 if (audit_pid)
209 panic("audit: %s\n", message);
210 break;
211 }
212}
213
214static inline int audit_rate_check(void)
215{
216 static unsigned long last_check = 0;
217 static int messages = 0;
218 static DEFINE_SPINLOCK(lock);
219 unsigned long flags;
220 unsigned long now;
221 unsigned long elapsed;
222 int retval = 0;
223
224 if (!audit_rate_limit) return 1;
225
226 spin_lock_irqsave(&lock, flags);
227 if (++messages < audit_rate_limit) {
228 retval = 1;
229 } else {
230 now = jiffies;
231 elapsed = now - last_check;
232 if (elapsed > HZ) {
233 last_check = now;
234 messages = 0;
235 retval = 1;
236 }
237 }
238 spin_unlock_irqrestore(&lock, flags);
239
240 return retval;
241}
242
243/**
244 * audit_log_lost - conditionally log lost audit message event
245 * @message: the message stating reason for lost audit message
246 *
247 * Emit at least 1 message per second, even if audit_rate_check is
248 * throttling.
249 * Always increment the lost messages counter.
250*/
251void audit_log_lost(const char *message)
252{
253 static unsigned long last_msg = 0;
254 static DEFINE_SPINLOCK(lock);
255 unsigned long flags;
256 unsigned long now;
257 int print;
258
259 atomic_inc(&audit_lost);
260
261 print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
262
263 if (!print) {
264 spin_lock_irqsave(&lock, flags);
265 now = jiffies;
266 if (now - last_msg > HZ) {
267 print = 1;
268 last_msg = now;
269 }
270 spin_unlock_irqrestore(&lock, flags);
271 }
272
273 if (print) {
274 if (printk_ratelimit())
275 pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
276 atomic_read(&audit_lost),
277 audit_rate_limit,
278 audit_backlog_limit);
279 audit_panic(message);
280 }
281}
282
283static int audit_log_config_change(char *function_name, u32 new, u32 old,
284 int allow_changes)
285{
286 struct audit_buffer *ab;
287 int rc = 0;
288
289 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
290 if (unlikely(!ab))
291 return rc;
292 audit_log_format(ab, "%s=%u old=%u", function_name, new, old);
293 audit_log_session_info(ab);
294 rc = audit_log_task_context(ab);
295 if (rc)
296 allow_changes = 0; /* Something weird, deny request */
297 audit_log_format(ab, " res=%d", allow_changes);
298 audit_log_end(ab);
299 return rc;
300}
301
302static int audit_do_config_change(char *function_name, u32 *to_change, u32 new)
303{
304 int allow_changes, rc = 0;
305 u32 old = *to_change;
306
307 /* check if we are locked */
308 if (audit_enabled == AUDIT_LOCKED)
309 allow_changes = 0;
310 else
311 allow_changes = 1;
312
313 if (audit_enabled != AUDIT_OFF) {
314 rc = audit_log_config_change(function_name, new, old, allow_changes);
315 if (rc)
316 allow_changes = 0;
317 }
318
319 /* If we are allowed, make the change */
320 if (allow_changes == 1)
321 *to_change = new;
322 /* Not allowed, update reason */
323 else if (rc == 0)
324 rc = -EPERM;
325 return rc;
326}
327
328static int audit_set_rate_limit(u32 limit)
329{
330 return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit);
331}
332
333static int audit_set_backlog_limit(u32 limit)
334{
335 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit);
336}
337
338static int audit_set_backlog_wait_time(u32 timeout)
339{
340 return audit_do_config_change("audit_backlog_wait_time",
341 &audit_backlog_wait_time, timeout);
342}
343
344static int audit_set_enabled(u32 state)
345{
346 int rc;
347 if (state < AUDIT_OFF || state > AUDIT_LOCKED)
348 return -EINVAL;
349
350 rc = audit_do_config_change("audit_enabled", &audit_enabled, state);
351 if (!rc)
352 audit_ever_enabled |= !!state;
353
354 return rc;
355}
356
357static int audit_set_failure(u32 state)
358{
359 if (state != AUDIT_FAIL_SILENT
360 && state != AUDIT_FAIL_PRINTK
361 && state != AUDIT_FAIL_PANIC)
362 return -EINVAL;
363
364 return audit_do_config_change("audit_failure", &audit_failure, state);
365}
366
367/*
368 * Queue skbs to be sent to auditd when/if it comes back. These skbs should
369 * already have been sent via prink/syslog and so if these messages are dropped
370 * it is not a huge concern since we already passed the audit_log_lost()
371 * notification and stuff. This is just nice to get audit messages during
372 * boot before auditd is running or messages generated while auditd is stopped.
373 * This only holds messages is audit_default is set, aka booting with audit=1
374 * or building your kernel that way.
375 */
376static void audit_hold_skb(struct sk_buff *skb)
377{
378 if (audit_default &&
379 (!audit_backlog_limit ||
380 skb_queue_len(&audit_skb_hold_queue) < audit_backlog_limit))
381 skb_queue_tail(&audit_skb_hold_queue, skb);
382 else
383 kfree_skb(skb);
384}
385
386/*
387 * For one reason or another this nlh isn't getting delivered to the userspace
388 * audit daemon, just send it to printk.
389 */
390static void audit_printk_skb(struct sk_buff *skb)
391{
392 struct nlmsghdr *nlh = nlmsg_hdr(skb);
393 char *data = nlmsg_data(nlh);
394
395 if (nlh->nlmsg_type != AUDIT_EOE) {
396 if (printk_ratelimit())
397 pr_notice("type=%d %s\n", nlh->nlmsg_type, data);
398 else
399 audit_log_lost("printk limit exceeded");
400 }
401
402 audit_hold_skb(skb);
403}
404
405static void kauditd_send_skb(struct sk_buff *skb)
406{
407 int err;
408 /* take a reference in case we can't send it and we want to hold it */
409 skb_get(skb);
410 err = netlink_unicast(audit_sock, skb, audit_nlk_portid, 0);
411 if (err < 0) {
412 BUG_ON(err != -ECONNREFUSED); /* Shouldn't happen */
413 if (audit_pid) {
414 pr_err("*NO* daemon at audit_pid=%d\n", audit_pid);
415 audit_log_lost("auditd disappeared");
416 audit_pid = 0;
417 audit_sock = NULL;
418 }
419 /* we might get lucky and get this in the next auditd */
420 audit_hold_skb(skb);
421 } else
422 /* drop the extra reference if sent ok */
423 consume_skb(skb);
424}
425
426/*
427 * flush_hold_queue - empty the hold queue if auditd appears
428 *
429 * If auditd just started, drain the queue of messages already
430 * sent to syslog/printk. Remember loss here is ok. We already
431 * called audit_log_lost() if it didn't go out normally. so the
432 * race between the skb_dequeue and the next check for audit_pid
433 * doesn't matter.
434 *
435 * If you ever find kauditd to be too slow we can get a perf win
436 * by doing our own locking and keeping better track if there
437 * are messages in this queue. I don't see the need now, but
438 * in 5 years when I want to play with this again I'll see this
439 * note and still have no friggin idea what i'm thinking today.
440 */
441static void flush_hold_queue(void)
442{
443 struct sk_buff *skb;
444
445 if (!audit_default || !audit_pid)
446 return;
447
448 skb = skb_dequeue(&audit_skb_hold_queue);
449 if (likely(!skb))
450 return;
451
452 while (skb && audit_pid) {
453 kauditd_send_skb(skb);
454 skb = skb_dequeue(&audit_skb_hold_queue);
455 }
456
457 /*
458 * if auditd just disappeared but we
459 * dequeued an skb we need to drop ref
460 */
461 if (skb)
462 consume_skb(skb);
463}
464
465static int kauditd_thread(void *dummy)
466{
467 set_freezable();
468 while (!kthread_should_stop()) {
469 struct sk_buff *skb;
470 DECLARE_WAITQUEUE(wait, current);
471
472 flush_hold_queue();
473
474 skb = skb_dequeue(&audit_skb_queue);
475
476 if (skb) {
477 if (skb_queue_len(&audit_skb_queue) <= audit_backlog_limit)
478 wake_up(&audit_backlog_wait);
479 if (audit_pid)
480 kauditd_send_skb(skb);
481 else
482 audit_printk_skb(skb);
483 continue;
484 }
485 set_current_state(TASK_INTERRUPTIBLE);
486 add_wait_queue(&kauditd_wait, &wait);
487
488 if (!skb_queue_len(&audit_skb_queue)) {
489 try_to_freeze();
490 schedule();
491 }
492
493 __set_current_state(TASK_RUNNING);
494 remove_wait_queue(&kauditd_wait, &wait);
495 }
496 return 0;
497}
498
499int audit_send_list(void *_dest)
500{
501 struct audit_netlink_list *dest = _dest;
502 struct sk_buff *skb;
503 struct net *net = dest->net;
504 struct audit_net *aunet = net_generic(net, audit_net_id);
505
506 /* wait for parent to finish and send an ACK */
507 mutex_lock(&audit_cmd_mutex);
508 mutex_unlock(&audit_cmd_mutex);
509
510 while ((skb = __skb_dequeue(&dest->q)) != NULL)
511 netlink_unicast(aunet->nlsk, skb, dest->portid, 0);
512
513 put_net(net);
514 kfree(dest);
515
516 return 0;
517}
518
519struct sk_buff *audit_make_reply(__u32 portid, int seq, int type, int done,
520 int multi, const void *payload, int size)
521{
522 struct sk_buff *skb;
523 struct nlmsghdr *nlh;
524 void *data;
525 int flags = multi ? NLM_F_MULTI : 0;
526 int t = done ? NLMSG_DONE : type;
527
528 skb = nlmsg_new(size, GFP_KERNEL);
529 if (!skb)
530 return NULL;
531
532 nlh = nlmsg_put(skb, portid, seq, t, size, flags);
533 if (!nlh)
534 goto out_kfree_skb;
535 data = nlmsg_data(nlh);
536 memcpy(data, payload, size);
537 return skb;
538
539out_kfree_skb:
540 kfree_skb(skb);
541 return NULL;
542}
543
544static int audit_send_reply_thread(void *arg)
545{
546 struct audit_reply *reply = (struct audit_reply *)arg;
547 struct net *net = reply->net;
548 struct audit_net *aunet = net_generic(net, audit_net_id);
549
550 mutex_lock(&audit_cmd_mutex);
551 mutex_unlock(&audit_cmd_mutex);
552
553 /* Ignore failure. It'll only happen if the sender goes away,
554 because our timeout is set to infinite. */
555 netlink_unicast(aunet->nlsk , reply->skb, reply->portid, 0);
556 put_net(net);
557 kfree(reply);
558 return 0;
559}
560/**
561 * audit_send_reply - send an audit reply message via netlink
562 * @request_skb: skb of request we are replying to (used to target the reply)
563 * @seq: sequence number
564 * @type: audit message type
565 * @done: done (last) flag
566 * @multi: multi-part message flag
567 * @payload: payload data
568 * @size: payload size
569 *
570 * Allocates an skb, builds the netlink message, and sends it to the port id.
571 * No failure notifications.
572 */
573static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
574 int multi, const void *payload, int size)
575{
576 u32 portid = NETLINK_CB(request_skb).portid;
577 struct net *net = sock_net(NETLINK_CB(request_skb).sk);
578 struct sk_buff *skb;
579 struct task_struct *tsk;
580 struct audit_reply *reply = kmalloc(sizeof(struct audit_reply),
581 GFP_KERNEL);
582
583 if (!reply)
584 return;
585
586 skb = audit_make_reply(portid, seq, type, done, multi, payload, size);
587 if (!skb)
588 goto out;
589
590 reply->net = get_net(net);
591 reply->portid = portid;
592 reply->skb = skb;
593
594 tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
595 if (!IS_ERR(tsk))
596 return;
597 kfree_skb(skb);
598out:
599 kfree(reply);
600}
601
602/*
603 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
604 * control messages.
605 */
606static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
607{
608 int err = 0;
609
610 /* Only support initial user namespace for now. */
611 /*
612 * We return ECONNREFUSED because it tricks userspace into thinking
613 * that audit was not configured into the kernel. Lots of users
614 * configure their PAM stack (because that's what the distro does)
615 * to reject login if unable to send messages to audit. If we return
616 * ECONNREFUSED the PAM stack thinks the kernel does not have audit
617 * configured in and will let login proceed. If we return EPERM
618 * userspace will reject all logins. This should be removed when we
619 * support non init namespaces!!
620 */
621 if (current_user_ns() != &init_user_ns)
622 return -ECONNREFUSED;
623
624 switch (msg_type) {
625 case AUDIT_LIST:
626 case AUDIT_ADD:
627 case AUDIT_DEL:
628 return -EOPNOTSUPP;
629 case AUDIT_GET:
630 case AUDIT_SET:
631 case AUDIT_GET_FEATURE:
632 case AUDIT_SET_FEATURE:
633 case AUDIT_LIST_RULES:
634 case AUDIT_ADD_RULE:
635 case AUDIT_DEL_RULE:
636 case AUDIT_SIGNAL_INFO:
637 case AUDIT_TTY_GET:
638 case AUDIT_TTY_SET:
639 case AUDIT_TRIM:
640 case AUDIT_MAKE_EQUIV:
641 /* Only support auditd and auditctl in initial pid namespace
642 * for now. */
643 if ((task_active_pid_ns(current) != &init_pid_ns))
644 return -EPERM;
645
646 if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
647 err = -EPERM;
648 break;
649 case AUDIT_USER:
650 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
651 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
652 if (!netlink_capable(skb, CAP_AUDIT_WRITE))
653 err = -EPERM;
654 break;
655 default: /* bad msg */
656 err = -EINVAL;
657 }
658
659 return err;
660}
661
662static int audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
663{
664 int rc = 0;
665 uid_t uid = from_kuid(&init_user_ns, current_uid());
666 pid_t pid = task_tgid_nr(current);
667
668 if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
669 *ab = NULL;
670 return rc;
671 }
672
673 *ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
674 if (unlikely(!*ab))
675 return rc;
676 audit_log_format(*ab, "pid=%d uid=%u", pid, uid);
677 audit_log_session_info(*ab);
678 audit_log_task_context(*ab);
679
680 return rc;
681}
682
683int is_audit_feature_set(int i)
684{
685 return af.features & AUDIT_FEATURE_TO_MASK(i);
686}
687
688
689static int audit_get_feature(struct sk_buff *skb)
690{
691 u32 seq;
692
693 seq = nlmsg_hdr(skb)->nlmsg_seq;
694
695 audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &af, sizeof(af));
696
697 return 0;
698}
699
700static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
701 u32 old_lock, u32 new_lock, int res)
702{
703 struct audit_buffer *ab;
704
705 if (audit_enabled == AUDIT_OFF)
706 return;
707
708 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_FEATURE_CHANGE);
709 audit_log_task_info(ab, current);
710 audit_log_format(ab, "feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
711 audit_feature_names[which], !!old_feature, !!new_feature,
712 !!old_lock, !!new_lock, res);
713 audit_log_end(ab);
714}
715
716static int audit_set_feature(struct sk_buff *skb)
717{
718 struct audit_features *uaf;
719 int i;
720
721 BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > sizeof(audit_feature_names)/sizeof(audit_feature_names[0]));
722 uaf = nlmsg_data(nlmsg_hdr(skb));
723
724 /* if there is ever a version 2 we should handle that here */
725
726 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
727 u32 feature = AUDIT_FEATURE_TO_MASK(i);
728 u32 old_feature, new_feature, old_lock, new_lock;
729
730 /* if we are not changing this feature, move along */
731 if (!(feature & uaf->mask))
732 continue;
733
734 old_feature = af.features & feature;
735 new_feature = uaf->features & feature;
736 new_lock = (uaf->lock | af.lock) & feature;
737 old_lock = af.lock & feature;
738
739 /* are we changing a locked feature? */
740 if (old_lock && (new_feature != old_feature)) {
741 audit_log_feature_change(i, old_feature, new_feature,
742 old_lock, new_lock, 0);
743 return -EPERM;
744 }
745 }
746 /* nothing invalid, do the changes */
747 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
748 u32 feature = AUDIT_FEATURE_TO_MASK(i);
749 u32 old_feature, new_feature, old_lock, new_lock;
750
751 /* if we are not changing this feature, move along */
752 if (!(feature & uaf->mask))
753 continue;
754
755 old_feature = af.features & feature;
756 new_feature = uaf->features & feature;
757 old_lock = af.lock & feature;
758 new_lock = (uaf->lock | af.lock) & feature;
759
760 if (new_feature != old_feature)
761 audit_log_feature_change(i, old_feature, new_feature,
762 old_lock, new_lock, 1);
763
764 if (new_feature)
765 af.features |= feature;
766 else
767 af.features &= ~feature;
768 af.lock |= new_lock;
769 }
770
771 return 0;
772}
773
774static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
775{
776 u32 seq;
777 void *data;
778 int err;
779 struct audit_buffer *ab;
780 u16 msg_type = nlh->nlmsg_type;
781 struct audit_sig_info *sig_data;
782 char *ctx = NULL;
783 u32 len;
784
785 err = audit_netlink_ok(skb, msg_type);
786 if (err)
787 return err;
788
789 /* As soon as there's any sign of userspace auditd,
790 * start kauditd to talk to it */
791 if (!kauditd_task) {
792 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
793 if (IS_ERR(kauditd_task)) {
794 err = PTR_ERR(kauditd_task);
795 kauditd_task = NULL;
796 return err;
797 }
798 }
799 seq = nlh->nlmsg_seq;
800 data = nlmsg_data(nlh);
801
802 switch (msg_type) {
803 case AUDIT_GET: {
804 struct audit_status s;
805 memset(&s, 0, sizeof(s));
806 s.enabled = audit_enabled;
807 s.failure = audit_failure;
808 s.pid = audit_pid;
809 s.rate_limit = audit_rate_limit;
810 s.backlog_limit = audit_backlog_limit;
811 s.lost = atomic_read(&audit_lost);
812 s.backlog = skb_queue_len(&audit_skb_queue);
813 s.version = AUDIT_VERSION_LATEST;
814 s.backlog_wait_time = audit_backlog_wait_time;
815 audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
816 break;
817 }
818 case AUDIT_SET: {
819 struct audit_status s;
820 memset(&s, 0, sizeof(s));
821 /* guard against past and future API changes */
822 memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
823 if (s.mask & AUDIT_STATUS_ENABLED) {
824 err = audit_set_enabled(s.enabled);
825 if (err < 0)
826 return err;
827 }
828 if (s.mask & AUDIT_STATUS_FAILURE) {
829 err = audit_set_failure(s.failure);
830 if (err < 0)
831 return err;
832 }
833 if (s.mask & AUDIT_STATUS_PID) {
834 int new_pid = s.pid;
835
836 if ((!new_pid) && (task_tgid_vnr(current) != audit_pid))
837 return -EACCES;
838 if (audit_enabled != AUDIT_OFF)
839 audit_log_config_change("audit_pid", new_pid, audit_pid, 1);
840 audit_pid = new_pid;
841 audit_nlk_portid = NETLINK_CB(skb).portid;
842 audit_sock = skb->sk;
843 }
844 if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
845 err = audit_set_rate_limit(s.rate_limit);
846 if (err < 0)
847 return err;
848 }
849 if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
850 err = audit_set_backlog_limit(s.backlog_limit);
851 if (err < 0)
852 return err;
853 }
854 if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
855 if (sizeof(s) > (size_t)nlh->nlmsg_len)
856 return -EINVAL;
857 if (s.backlog_wait_time < 0 ||
858 s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
859 return -EINVAL;
860 err = audit_set_backlog_wait_time(s.backlog_wait_time);
861 if (err < 0)
862 return err;
863 }
864 break;
865 }
866 case AUDIT_GET_FEATURE:
867 err = audit_get_feature(skb);
868 if (err)
869 return err;
870 break;
871 case AUDIT_SET_FEATURE:
872 err = audit_set_feature(skb);
873 if (err)
874 return err;
875 break;
876 case AUDIT_USER:
877 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
878 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
879 if (!audit_enabled && msg_type != AUDIT_USER_AVC)
880 return 0;
881
882 err = audit_filter_user(msg_type);
883 if (err == 1) { /* match or error */
884 err = 0;
885 if (msg_type == AUDIT_USER_TTY) {
886 err = tty_audit_push_current();
887 if (err)
888 break;
889 }
890 mutex_unlock(&audit_cmd_mutex);
891 audit_log_common_recv_msg(&ab, msg_type);
892 if (msg_type != AUDIT_USER_TTY)
893 audit_log_format(ab, " msg='%.*s'",
894 AUDIT_MESSAGE_TEXT_MAX,
895 (char *)data);
896 else {
897 int size;
898
899 audit_log_format(ab, " data=");
900 size = nlmsg_len(nlh);
901 if (size > 0 &&
902 ((unsigned char *)data)[size - 1] == '\0')
903 size--;
904 audit_log_n_untrustedstring(ab, data, size);
905 }
906 audit_set_portid(ab, NETLINK_CB(skb).portid);
907 audit_log_end(ab);
908 mutex_lock(&audit_cmd_mutex);
909 }
910 break;
911 case AUDIT_ADD_RULE:
912 case AUDIT_DEL_RULE:
913 if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
914 return -EINVAL;
915 if (audit_enabled == AUDIT_LOCKED) {
916 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
917 audit_log_format(ab, " audit_enabled=%d res=0", audit_enabled);
918 audit_log_end(ab);
919 return -EPERM;
920 }
921 err = audit_rule_change(msg_type, NETLINK_CB(skb).portid,
922 seq, data, nlmsg_len(nlh));
923 break;
924 case AUDIT_LIST_RULES:
925 err = audit_list_rules_send(skb, seq);
926 break;
927 case AUDIT_TRIM:
928 audit_trim_trees();
929 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
930 audit_log_format(ab, " op=trim res=1");
931 audit_log_end(ab);
932 break;
933 case AUDIT_MAKE_EQUIV: {
934 void *bufp = data;
935 u32 sizes[2];
936 size_t msglen = nlmsg_len(nlh);
937 char *old, *new;
938
939 err = -EINVAL;
940 if (msglen < 2 * sizeof(u32))
941 break;
942 memcpy(sizes, bufp, 2 * sizeof(u32));
943 bufp += 2 * sizeof(u32);
944 msglen -= 2 * sizeof(u32);
945 old = audit_unpack_string(&bufp, &msglen, sizes[0]);
946 if (IS_ERR(old)) {
947 err = PTR_ERR(old);
948 break;
949 }
950 new = audit_unpack_string(&bufp, &msglen, sizes[1]);
951 if (IS_ERR(new)) {
952 err = PTR_ERR(new);
953 kfree(old);
954 break;
955 }
956 /* OK, here comes... */
957 err = audit_tag_tree(old, new);
958
959 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
960
961 audit_log_format(ab, " op=make_equiv old=");
962 audit_log_untrustedstring(ab, old);
963 audit_log_format(ab, " new=");
964 audit_log_untrustedstring(ab, new);
965 audit_log_format(ab, " res=%d", !err);
966 audit_log_end(ab);
967 kfree(old);
968 kfree(new);
969 break;
970 }
971 case AUDIT_SIGNAL_INFO:
972 len = 0;
973 if (audit_sig_sid) {
974 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
975 if (err)
976 return err;
977 }
978 sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
979 if (!sig_data) {
980 if (audit_sig_sid)
981 security_release_secctx(ctx, len);
982 return -ENOMEM;
983 }
984 sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
985 sig_data->pid = audit_sig_pid;
986 if (audit_sig_sid) {
987 memcpy(sig_data->ctx, ctx, len);
988 security_release_secctx(ctx, len);
989 }
990 audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
991 sig_data, sizeof(*sig_data) + len);
992 kfree(sig_data);
993 break;
994 case AUDIT_TTY_GET: {
995 struct audit_tty_status s;
996 struct task_struct *tsk = current;
997
998 spin_lock(&tsk->sighand->siglock);
999 s.enabled = tsk->signal->audit_tty;
1000 s.log_passwd = tsk->signal->audit_tty_log_passwd;
1001 spin_unlock(&tsk->sighand->siglock);
1002
1003 audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
1004 break;
1005 }
1006 case AUDIT_TTY_SET: {
1007 struct audit_tty_status s, old;
1008 struct task_struct *tsk = current;
1009 struct audit_buffer *ab;
1010
1011 memset(&s, 0, sizeof(s));
1012 /* guard against past and future API changes */
1013 memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
1014 /* check if new data is valid */
1015 if ((s.enabled != 0 && s.enabled != 1) ||
1016 (s.log_passwd != 0 && s.log_passwd != 1))
1017 err = -EINVAL;
1018
1019 spin_lock(&tsk->sighand->siglock);
1020 old.enabled = tsk->signal->audit_tty;
1021 old.log_passwd = tsk->signal->audit_tty_log_passwd;
1022 if (!err) {
1023 tsk->signal->audit_tty = s.enabled;
1024 tsk->signal->audit_tty_log_passwd = s.log_passwd;
1025 }
1026 spin_unlock(&tsk->sighand->siglock);
1027
1028 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1029 audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
1030 " old-log_passwd=%d new-log_passwd=%d res=%d",
1031 old.enabled, s.enabled, old.log_passwd,
1032 s.log_passwd, !err);
1033 audit_log_end(ab);
1034 break;
1035 }
1036 default:
1037 err = -EINVAL;
1038 break;
1039 }
1040
1041 return err < 0 ? err : 0;
1042}
1043
1044/*
1045 * Get message from skb. Each message is processed by audit_receive_msg.
1046 * Malformed skbs with wrong length are discarded silently.
1047 */
1048static void audit_receive_skb(struct sk_buff *skb)
1049{
1050 struct nlmsghdr *nlh;
1051 /*
1052 * len MUST be signed for nlmsg_next to be able to dec it below 0
1053 * if the nlmsg_len was not aligned
1054 */
1055 int len;
1056 int err;
1057
1058 nlh = nlmsg_hdr(skb);
1059 len = skb->len;
1060
1061 while (nlmsg_ok(nlh, len)) {
1062 err = audit_receive_msg(skb, nlh);
1063 /* if err or if this message says it wants a response */
1064 if (err || (nlh->nlmsg_flags & NLM_F_ACK))
1065 netlink_ack(skb, nlh, err);
1066
1067 nlh = nlmsg_next(nlh, &len);
1068 }
1069}
1070
1071/* Receive messages from netlink socket. */
1072static void audit_receive(struct sk_buff *skb)
1073{
1074 mutex_lock(&audit_cmd_mutex);
1075 audit_receive_skb(skb);
1076 mutex_unlock(&audit_cmd_mutex);
1077}
1078
1079static int __net_init audit_net_init(struct net *net)
1080{
1081 struct netlink_kernel_cfg cfg = {
1082 .input = audit_receive,
1083 };
1084
1085 struct audit_net *aunet = net_generic(net, audit_net_id);
1086
1087 aunet->nlsk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
1088 if (aunet->nlsk == NULL) {
1089 audit_panic("cannot initialize netlink socket in namespace");
1090 return -ENOMEM;
1091 }
1092 aunet->nlsk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
1093 return 0;
1094}
1095
1096static void __net_exit audit_net_exit(struct net *net)
1097{
1098 struct audit_net *aunet = net_generic(net, audit_net_id);
1099 struct sock *sock = aunet->nlsk;
1100 if (sock == audit_sock) {
1101 audit_pid = 0;
1102 audit_sock = NULL;
1103 }
1104
1105 RCU_INIT_POINTER(aunet->nlsk, NULL);
1106 synchronize_net();
1107 netlink_kernel_release(sock);
1108}
1109
1110static struct pernet_operations audit_net_ops __net_initdata = {
1111 .init = audit_net_init,
1112 .exit = audit_net_exit,
1113 .id = &audit_net_id,
1114 .size = sizeof(struct audit_net),
1115};
1116
1117/* Initialize audit support at boot time. */
1118static int __init audit_init(void)
1119{
1120 int i;
1121
1122 if (audit_initialized == AUDIT_DISABLED)
1123 return 0;
1124
1125 pr_info("initializing netlink subsys (%s)\n",
1126 audit_default ? "enabled" : "disabled");
1127 register_pernet_subsys(&audit_net_ops);
1128
1129 skb_queue_head_init(&audit_skb_queue);
1130 skb_queue_head_init(&audit_skb_hold_queue);
1131 audit_initialized = AUDIT_INITIALIZED;
1132 audit_enabled = audit_default;
1133 audit_ever_enabled |= !!audit_default;
1134
1135 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized");
1136
1137 for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
1138 INIT_LIST_HEAD(&audit_inode_hash[i]);
1139
1140 return 0;
1141}
1142__initcall(audit_init);
1143
1144/* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
1145static int __init audit_enable(char *str)
1146{
1147 audit_default = !!simple_strtol(str, NULL, 0);
1148 if (!audit_default)
1149 audit_initialized = AUDIT_DISABLED;
1150
1151 pr_info("%s\n", audit_default ?
1152 "enabled (after initialization)" : "disabled (until reboot)");
1153
1154 return 1;
1155}
1156__setup("audit=", audit_enable);
1157
1158/* Process kernel command-line parameter at boot time.
1159 * audit_backlog_limit=<n> */
1160static int __init audit_backlog_limit_set(char *str)
1161{
1162 u32 audit_backlog_limit_arg;
1163
1164 pr_info("audit_backlog_limit: ");
1165 if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
1166 pr_cont("using default of %u, unable to parse %s\n",
1167 audit_backlog_limit, str);
1168 return 1;
1169 }
1170
1171 audit_backlog_limit = audit_backlog_limit_arg;
1172 pr_cont("%d\n", audit_backlog_limit);
1173
1174 return 1;
1175}
1176__setup("audit_backlog_limit=", audit_backlog_limit_set);
1177
1178static void audit_buffer_free(struct audit_buffer *ab)
1179{
1180 unsigned long flags;
1181
1182 if (!ab)
1183 return;
1184
1185 if (ab->skb)
1186 kfree_skb(ab->skb);
1187
1188 spin_lock_irqsave(&audit_freelist_lock, flags);
1189 if (audit_freelist_count > AUDIT_MAXFREE)
1190 kfree(ab);
1191 else {
1192 audit_freelist_count++;
1193 list_add(&ab->list, &audit_freelist);
1194 }
1195 spin_unlock_irqrestore(&audit_freelist_lock, flags);
1196}
1197
1198static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx,
1199 gfp_t gfp_mask, int type)
1200{
1201 unsigned long flags;
1202 struct audit_buffer *ab = NULL;
1203 struct nlmsghdr *nlh;
1204
1205 spin_lock_irqsave(&audit_freelist_lock, flags);
1206 if (!list_empty(&audit_freelist)) {
1207 ab = list_entry(audit_freelist.next,
1208 struct audit_buffer, list);
1209 list_del(&ab->list);
1210 --audit_freelist_count;
1211 }
1212 spin_unlock_irqrestore(&audit_freelist_lock, flags);
1213
1214 if (!ab) {
1215 ab = kmalloc(sizeof(*ab), gfp_mask);
1216 if (!ab)
1217 goto err;
1218 }
1219
1220 ab->ctx = ctx;
1221 ab->gfp_mask = gfp_mask;
1222
1223 ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
1224 if (!ab->skb)
1225 goto err;
1226
1227 nlh = nlmsg_put(ab->skb, 0, 0, type, 0, 0);
1228 if (!nlh)
1229 goto out_kfree_skb;
1230
1231 return ab;
1232
1233out_kfree_skb:
1234 kfree_skb(ab->skb);
1235 ab->skb = NULL;
1236err:
1237 audit_buffer_free(ab);
1238 return NULL;
1239}
1240
1241/**
1242 * audit_serial - compute a serial number for the audit record
1243 *
1244 * Compute a serial number for the audit record. Audit records are
1245 * written to user-space as soon as they are generated, so a complete
1246 * audit record may be written in several pieces. The timestamp of the
1247 * record and this serial number are used by the user-space tools to
1248 * determine which pieces belong to the same audit record. The
1249 * (timestamp,serial) tuple is unique for each syscall and is live from
1250 * syscall entry to syscall exit.
1251 *
1252 * NOTE: Another possibility is to store the formatted records off the
1253 * audit context (for those records that have a context), and emit them
1254 * all at syscall exit. However, this could delay the reporting of
1255 * significant errors until syscall exit (or never, if the system
1256 * halts).
1257 */
1258unsigned int audit_serial(void)
1259{
1260 static DEFINE_SPINLOCK(serial_lock);
1261 static unsigned int serial = 0;
1262
1263 unsigned long flags;
1264 unsigned int ret;
1265
1266 spin_lock_irqsave(&serial_lock, flags);
1267 do {
1268 ret = ++serial;
1269 } while (unlikely(!ret));
1270 spin_unlock_irqrestore(&serial_lock, flags);
1271
1272 return ret;
1273}
1274
1275static inline void audit_get_stamp(struct audit_context *ctx,
1276 struct timespec *t, unsigned int *serial)
1277{
1278 if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
1279 *t = CURRENT_TIME;
1280 *serial = audit_serial();
1281 }
1282}
1283
1284/*
1285 * Wait for auditd to drain the queue a little
1286 */
1287static long wait_for_auditd(long sleep_time)
1288{
1289 DECLARE_WAITQUEUE(wait, current);
1290 set_current_state(TASK_UNINTERRUPTIBLE);
1291 add_wait_queue_exclusive(&audit_backlog_wait, &wait);
1292
1293 if (audit_backlog_limit &&
1294 skb_queue_len(&audit_skb_queue) > audit_backlog_limit)
1295 sleep_time = schedule_timeout(sleep_time);
1296
1297 __set_current_state(TASK_RUNNING);
1298 remove_wait_queue(&audit_backlog_wait, &wait);
1299
1300 return sleep_time;
1301}
1302
1303/**
1304 * audit_log_start - obtain an audit buffer
1305 * @ctx: audit_context (may be NULL)
1306 * @gfp_mask: type of allocation
1307 * @type: audit message type
1308 *
1309 * Returns audit_buffer pointer on success or NULL on error.
1310 *
1311 * Obtain an audit buffer. This routine does locking to obtain the
1312 * audit buffer, but then no locking is required for calls to
1313 * audit_log_*format. If the task (ctx) is a task that is currently in a
1314 * syscall, then the syscall is marked as auditable and an audit record
1315 * will be written at syscall exit. If there is no associated task, then
1316 * task context (ctx) should be NULL.
1317 */
1318struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1319 int type)
1320{
1321 struct audit_buffer *ab = NULL;
1322 struct timespec t;
1323 unsigned int uninitialized_var(serial);
1324 int reserve = 5; /* Allow atomic callers to go up to five
1325 entries over the normal backlog limit */
1326 unsigned long timeout_start = jiffies;
1327
1328 if (audit_initialized != AUDIT_INITIALIZED)
1329 return NULL;
1330
1331 if (unlikely(audit_filter_type(type)))
1332 return NULL;
1333
1334 if (gfp_mask & __GFP_WAIT) {
1335 if (audit_pid && audit_pid == current->pid)
1336 gfp_mask &= ~__GFP_WAIT;
1337 else
1338 reserve = 0;
1339 }
1340
1341 while (audit_backlog_limit
1342 && skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) {
1343 if (gfp_mask & __GFP_WAIT && audit_backlog_wait_time) {
1344 long sleep_time;
1345
1346 sleep_time = timeout_start + audit_backlog_wait_time - jiffies;
1347 if (sleep_time > 0) {
1348 sleep_time = wait_for_auditd(sleep_time);
1349 if (sleep_time > 0)
1350 continue;
1351 }
1352 }
1353 if (audit_rate_check() && printk_ratelimit())
1354 pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
1355 skb_queue_len(&audit_skb_queue),
1356 audit_backlog_limit);
1357 audit_log_lost("backlog limit exceeded");
1358 audit_backlog_wait_time = audit_backlog_wait_overflow;
1359 wake_up(&audit_backlog_wait);
1360 return NULL;
1361 }
1362
1363 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
1364
1365 ab = audit_buffer_alloc(ctx, gfp_mask, type);
1366 if (!ab) {
1367 audit_log_lost("out of memory in audit_log_start");
1368 return NULL;
1369 }
1370
1371 audit_get_stamp(ab->ctx, &t, &serial);
1372
1373 audit_log_format(ab, "audit(%lu.%03lu:%u): ",
1374 t.tv_sec, t.tv_nsec/1000000, serial);
1375 return ab;
1376}
1377
1378/**
1379 * audit_expand - expand skb in the audit buffer
1380 * @ab: audit_buffer
1381 * @extra: space to add at tail of the skb
1382 *
1383 * Returns 0 (no space) on failed expansion, or available space if
1384 * successful.
1385 */
1386static inline int audit_expand(struct audit_buffer *ab, int extra)
1387{
1388 struct sk_buff *skb = ab->skb;
1389 int oldtail = skb_tailroom(skb);
1390 int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1391 int newtail = skb_tailroom(skb);
1392
1393 if (ret < 0) {
1394 audit_log_lost("out of memory in audit_expand");
1395 return 0;
1396 }
1397
1398 skb->truesize += newtail - oldtail;
1399 return newtail;
1400}
1401
1402/*
1403 * Format an audit message into the audit buffer. If there isn't enough
1404 * room in the audit buffer, more room will be allocated and vsnprint
1405 * will be called a second time. Currently, we assume that a printk
1406 * can't format message larger than 1024 bytes, so we don't either.
1407 */
1408static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1409 va_list args)
1410{
1411 int len, avail;
1412 struct sk_buff *skb;
1413 va_list args2;
1414
1415 if (!ab)
1416 return;
1417
1418 BUG_ON(!ab->skb);
1419 skb = ab->skb;
1420 avail = skb_tailroom(skb);
1421 if (avail == 0) {
1422 avail = audit_expand(ab, AUDIT_BUFSIZ);
1423 if (!avail)
1424 goto out;
1425 }
1426 va_copy(args2, args);
1427 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1428 if (len >= avail) {
1429 /* The printk buffer is 1024 bytes long, so if we get
1430 * here and AUDIT_BUFSIZ is at least 1024, then we can
1431 * log everything that printk could have logged. */
1432 avail = audit_expand(ab,
1433 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1434 if (!avail)
1435 goto out_va_end;
1436 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1437 }
1438 if (len > 0)
1439 skb_put(skb, len);
1440out_va_end:
1441 va_end(args2);
1442out:
1443 return;
1444}
1445
1446/**
1447 * audit_log_format - format a message into the audit buffer.
1448 * @ab: audit_buffer
1449 * @fmt: format string
1450 * @...: optional parameters matching @fmt string
1451 *
1452 * All the work is done in audit_log_vformat.
1453 */
1454void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1455{
1456 va_list args;
1457
1458 if (!ab)
1459 return;
1460 va_start(args, fmt);
1461 audit_log_vformat(ab, fmt, args);
1462 va_end(args);
1463}
1464
1465/**
1466 * audit_log_hex - convert a buffer to hex and append it to the audit skb
1467 * @ab: the audit_buffer
1468 * @buf: buffer to convert to hex
1469 * @len: length of @buf to be converted
1470 *
1471 * No return value; failure to expand is silently ignored.
1472 *
1473 * This function will take the passed buf and convert it into a string of
1474 * ascii hex digits. The new string is placed onto the skb.
1475 */
1476void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
1477 size_t len)
1478{
1479 int i, avail, new_len;
1480 unsigned char *ptr;
1481 struct sk_buff *skb;
1482
1483 if (!ab)
1484 return;
1485
1486 BUG_ON(!ab->skb);
1487 skb = ab->skb;
1488 avail = skb_tailroom(skb);
1489 new_len = len<<1;
1490 if (new_len >= avail) {
1491 /* Round the buffer request up to the next multiple */
1492 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1493 avail = audit_expand(ab, new_len);
1494 if (!avail)
1495 return;
1496 }
1497
1498 ptr = skb_tail_pointer(skb);
1499 for (i = 0; i < len; i++)
1500 ptr = hex_byte_pack_upper(ptr, buf[i]);
1501 *ptr = 0;
1502 skb_put(skb, len << 1); /* new string is twice the old string */
1503}
1504
1505/*
1506 * Format a string of no more than slen characters into the audit buffer,
1507 * enclosed in quote marks.
1508 */
1509void audit_log_n_string(struct audit_buffer *ab, const char *string,
1510 size_t slen)
1511{
1512 int avail, new_len;
1513 unsigned char *ptr;
1514 struct sk_buff *skb;
1515
1516 if (!ab)
1517 return;
1518
1519 BUG_ON(!ab->skb);
1520 skb = ab->skb;
1521 avail = skb_tailroom(skb);
1522 new_len = slen + 3; /* enclosing quotes + null terminator */
1523 if (new_len > avail) {
1524 avail = audit_expand(ab, new_len);
1525 if (!avail)
1526 return;
1527 }
1528 ptr = skb_tail_pointer(skb);
1529 *ptr++ = '"';
1530 memcpy(ptr, string, slen);
1531 ptr += slen;
1532 *ptr++ = '"';
1533 *ptr = 0;
1534 skb_put(skb, slen + 2); /* don't include null terminator */
1535}
1536
1537/**
1538 * audit_string_contains_control - does a string need to be logged in hex
1539 * @string: string to be checked
1540 * @len: max length of the string to check
1541 */
1542int audit_string_contains_control(const char *string, size_t len)
1543{
1544 const unsigned char *p;
1545 for (p = string; p < (const unsigned char *)string + len; p++) {
1546 if (*p == '"' || *p < 0x21 || *p > 0x7e)
1547 return 1;
1548 }
1549 return 0;
1550}
1551
1552/**
1553 * audit_log_n_untrustedstring - log a string that may contain random characters
1554 * @ab: audit_buffer
1555 * @len: length of string (not including trailing null)
1556 * @string: string to be logged
1557 *
1558 * This code will escape a string that is passed to it if the string
1559 * contains a control character, unprintable character, double quote mark,
1560 * or a space. Unescaped strings will start and end with a double quote mark.
1561 * Strings that are escaped are printed in hex (2 digits per char).
1562 *
1563 * The caller specifies the number of characters in the string to log, which may
1564 * or may not be the entire string.
1565 */
1566void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
1567 size_t len)
1568{
1569 if (audit_string_contains_control(string, len))
1570 audit_log_n_hex(ab, string, len);
1571 else
1572 audit_log_n_string(ab, string, len);
1573}
1574
1575/**
1576 * audit_log_untrustedstring - log a string that may contain random characters
1577 * @ab: audit_buffer
1578 * @string: string to be logged
1579 *
1580 * Same as audit_log_n_untrustedstring(), except that strlen is used to
1581 * determine string length.
1582 */
1583void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
1584{
1585 audit_log_n_untrustedstring(ab, string, strlen(string));
1586}
1587
1588/* This is a helper-function to print the escaped d_path */
1589void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
1590 const struct path *path)
1591{
1592 char *p, *pathname;
1593
1594 if (prefix)
1595 audit_log_format(ab, "%s", prefix);
1596
1597 /* We will allow 11 spaces for ' (deleted)' to be appended */
1598 pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
1599 if (!pathname) {
1600 audit_log_string(ab, "<no_memory>");
1601 return;
1602 }
1603 p = d_path(path, pathname, PATH_MAX+11);
1604 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
1605 /* FIXME: can we save some information here? */
1606 audit_log_string(ab, "<too_long>");
1607 } else
1608 audit_log_untrustedstring(ab, p);
1609 kfree(pathname);
1610}
1611
1612void audit_log_session_info(struct audit_buffer *ab)
1613{
1614 unsigned int sessionid = audit_get_sessionid(current);
1615 uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
1616
1617 audit_log_format(ab, " auid=%u ses=%u", auid, sessionid);
1618}
1619
1620void audit_log_key(struct audit_buffer *ab, char *key)
1621{
1622 audit_log_format(ab, " key=");
1623 if (key)
1624 audit_log_untrustedstring(ab, key);
1625 else
1626 audit_log_format(ab, "(null)");
1627}
1628
1629void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap)
1630{
1631 int i;
1632
1633 audit_log_format(ab, " %s=", prefix);
1634 CAP_FOR_EACH_U32(i) {
1635 audit_log_format(ab, "%08x",
1636 cap->cap[(_KERNEL_CAPABILITY_U32S-1) - i]);
1637 }
1638}
1639
1640void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
1641{
1642 kernel_cap_t *perm = &name->fcap.permitted;
1643 kernel_cap_t *inh = &name->fcap.inheritable;
1644 int log = 0;
1645
1646 if (!cap_isclear(*perm)) {
1647 audit_log_cap(ab, "cap_fp", perm);
1648 log = 1;
1649 }
1650 if (!cap_isclear(*inh)) {
1651 audit_log_cap(ab, "cap_fi", inh);
1652 log = 1;
1653 }
1654
1655 if (log)
1656 audit_log_format(ab, " cap_fe=%d cap_fver=%x",
1657 name->fcap.fE, name->fcap_ver);
1658}
1659
1660static inline int audit_copy_fcaps(struct audit_names *name,
1661 const struct dentry *dentry)
1662{
1663 struct cpu_vfs_cap_data caps;
1664 int rc;
1665
1666 if (!dentry)
1667 return 0;
1668
1669 rc = get_vfs_caps_from_disk(dentry, &caps);
1670 if (rc)
1671 return rc;
1672
1673 name->fcap.permitted = caps.permitted;
1674 name->fcap.inheritable = caps.inheritable;
1675 name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
1676 name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >>
1677 VFS_CAP_REVISION_SHIFT;
1678
1679 return 0;
1680}
1681
1682/* Copy inode data into an audit_names. */
1683void audit_copy_inode(struct audit_names *name, const struct dentry *dentry,
1684 const struct inode *inode)
1685{
1686 name->ino = inode->i_ino;
1687 name->dev = inode->i_sb->s_dev;
1688 name->mode = inode->i_mode;
1689 name->uid = inode->i_uid;
1690 name->gid = inode->i_gid;
1691 name->rdev = inode->i_rdev;
1692 security_inode_getsecid(inode, &name->osid);
1693 audit_copy_fcaps(name, dentry);
1694}
1695
1696/**
1697 * audit_log_name - produce AUDIT_PATH record from struct audit_names
1698 * @context: audit_context for the task
1699 * @n: audit_names structure with reportable details
1700 * @path: optional path to report instead of audit_names->name
1701 * @record_num: record number to report when handling a list of names
1702 * @call_panic: optional pointer to int that will be updated if secid fails
1703 */
1704void audit_log_name(struct audit_context *context, struct audit_names *n,
1705 struct path *path, int record_num, int *call_panic)
1706{
1707 struct audit_buffer *ab;
1708 ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH);
1709 if (!ab)
1710 return;
1711
1712 audit_log_format(ab, "item=%d", record_num);
1713
1714 if (path)
1715 audit_log_d_path(ab, " name=", path);
1716 else if (n->name) {
1717 switch (n->name_len) {
1718 case AUDIT_NAME_FULL:
1719 /* log the full path */
1720 audit_log_format(ab, " name=");
1721 audit_log_untrustedstring(ab, n->name->name);
1722 break;
1723 case 0:
1724 /* name was specified as a relative path and the
1725 * directory component is the cwd */
1726 audit_log_d_path(ab, " name=", &context->pwd);
1727 break;
1728 default:
1729 /* log the name's directory component */
1730 audit_log_format(ab, " name=");
1731 audit_log_n_untrustedstring(ab, n->name->name,
1732 n->name_len);
1733 }
1734 } else
1735 audit_log_format(ab, " name=(null)");
1736
1737 if (n->ino != (unsigned long)-1) {
1738 audit_log_format(ab, " inode=%lu"
1739 " dev=%02x:%02x mode=%#ho"
1740 " ouid=%u ogid=%u rdev=%02x:%02x",
1741 n->ino,
1742 MAJOR(n->dev),
1743 MINOR(n->dev),
1744 n->mode,
1745 from_kuid(&init_user_ns, n->uid),
1746 from_kgid(&init_user_ns, n->gid),
1747 MAJOR(n->rdev),
1748 MINOR(n->rdev));
1749 }
1750 if (n->osid != 0) {
1751 char *ctx = NULL;
1752 u32 len;
1753 if (security_secid_to_secctx(
1754 n->osid, &ctx, &len)) {
1755 audit_log_format(ab, " osid=%u", n->osid);
1756 if (call_panic)
1757 *call_panic = 2;
1758 } else {
1759 audit_log_format(ab, " obj=%s", ctx);
1760 security_release_secctx(ctx, len);
1761 }
1762 }
1763
1764 /* log the audit_names record type */
1765 audit_log_format(ab, " nametype=");
1766 switch(n->type) {
1767 case AUDIT_TYPE_NORMAL:
1768 audit_log_format(ab, "NORMAL");
1769 break;
1770 case AUDIT_TYPE_PARENT:
1771 audit_log_format(ab, "PARENT");
1772 break;
1773 case AUDIT_TYPE_CHILD_DELETE:
1774 audit_log_format(ab, "DELETE");
1775 break;
1776 case AUDIT_TYPE_CHILD_CREATE:
1777 audit_log_format(ab, "CREATE");
1778 break;
1779 default:
1780 audit_log_format(ab, "UNKNOWN");
1781 break;
1782 }
1783
1784 audit_log_fcaps(ab, n);
1785 audit_log_end(ab);
1786}
1787
1788int audit_log_task_context(struct audit_buffer *ab)
1789{
1790 char *ctx = NULL;
1791 unsigned len;
1792 int error;
1793 u32 sid;
1794
1795 security_task_getsecid(current, &sid);
1796 if (!sid)
1797 return 0;
1798
1799 error = security_secid_to_secctx(sid, &ctx, &len);
1800 if (error) {
1801 if (error != -EINVAL)
1802 goto error_path;
1803 return 0;
1804 }
1805
1806 audit_log_format(ab, " subj=%s", ctx);
1807 security_release_secctx(ctx, len);
1808 return 0;
1809
1810error_path:
1811 audit_panic("error in audit_log_task_context");
1812 return error;
1813}
1814EXPORT_SYMBOL(audit_log_task_context);
1815
1816void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
1817{
1818 const struct cred *cred;
1819 char name[sizeof(tsk->comm)];
1820 struct mm_struct *mm = tsk->mm;
1821 char *tty;
1822
1823 if (!ab)
1824 return;
1825
1826 /* tsk == current */
1827 cred = current_cred();
1828
1829 spin_lock_irq(&tsk->sighand->siglock);
1830 if (tsk->signal && tsk->signal->tty && tsk->signal->tty->name)
1831 tty = tsk->signal->tty->name;
1832 else
1833 tty = "(none)";
1834 spin_unlock_irq(&tsk->sighand->siglock);
1835
1836 audit_log_format(ab,
1837 " ppid=%d pid=%d auid=%u uid=%u gid=%u"
1838 " euid=%u suid=%u fsuid=%u"
1839 " egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
1840 task_ppid_nr(tsk),
1841 task_pid_nr(tsk),
1842 from_kuid(&init_user_ns, audit_get_loginuid(tsk)),
1843 from_kuid(&init_user_ns, cred->uid),
1844 from_kgid(&init_user_ns, cred->gid),
1845 from_kuid(&init_user_ns, cred->euid),
1846 from_kuid(&init_user_ns, cred->suid),
1847 from_kuid(&init_user_ns, cred->fsuid),
1848 from_kgid(&init_user_ns, cred->egid),
1849 from_kgid(&init_user_ns, cred->sgid),
1850 from_kgid(&init_user_ns, cred->fsgid),
1851 tty, audit_get_sessionid(tsk));
1852
1853 get_task_comm(name, tsk);
1854 audit_log_format(ab, " comm=");
1855 audit_log_untrustedstring(ab, name);
1856
1857 if (mm) {
1858 down_read(&mm->mmap_sem);
1859 if (mm->exe_file)
1860 audit_log_d_path(ab, " exe=", &mm->exe_file->f_path);
1861 up_read(&mm->mmap_sem);
1862 } else
1863 audit_log_format(ab, " exe=(null)");
1864 audit_log_task_context(ab);
1865}
1866EXPORT_SYMBOL(audit_log_task_info);
1867
1868/**
1869 * audit_log_link_denied - report a link restriction denial
1870 * @operation: specific link opreation
1871 * @link: the path that triggered the restriction
1872 */
1873void audit_log_link_denied(const char *operation, struct path *link)
1874{
1875 struct audit_buffer *ab;
1876 struct audit_names *name;
1877
1878 name = kzalloc(sizeof(*name), GFP_NOFS);
1879 if (!name)
1880 return;
1881
1882 /* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */
1883 ab = audit_log_start(current->audit_context, GFP_KERNEL,
1884 AUDIT_ANOM_LINK);
1885 if (!ab)
1886 goto out;
1887 audit_log_format(ab, "op=%s", operation);
1888 audit_log_task_info(ab, current);
1889 audit_log_format(ab, " res=0");
1890 audit_log_end(ab);
1891
1892 /* Generate AUDIT_PATH record with object. */
1893 name->type = AUDIT_TYPE_NORMAL;
1894 audit_copy_inode(name, link->dentry, link->dentry->d_inode);
1895 audit_log_name(current->audit_context, name, link, 0, NULL);
1896out:
1897 kfree(name);
1898}
1899
1900/**
1901 * audit_log_end - end one audit record
1902 * @ab: the audit_buffer
1903 *
1904 * The netlink_* functions cannot be called inside an irq context, so
1905 * the audit buffer is placed on a queue and a tasklet is scheduled to
1906 * remove them from the queue outside the irq context. May be called in
1907 * any context.
1908 */
1909void audit_log_end(struct audit_buffer *ab)
1910{
1911 if (!ab)
1912 return;
1913 if (!audit_rate_check()) {
1914 audit_log_lost("rate limit exceeded");
1915 } else {
1916 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
1917 nlh->nlmsg_len = ab->skb->len - NLMSG_HDRLEN;
1918
1919 if (audit_pid) {
1920 skb_queue_tail(&audit_skb_queue, ab->skb);
1921 wake_up_interruptible(&kauditd_wait);
1922 } else {
1923 audit_printk_skb(ab->skb);
1924 }
1925 ab->skb = NULL;
1926 }
1927 audit_buffer_free(ab);
1928}
1929
1930/**
1931 * audit_log - Log an audit record
1932 * @ctx: audit context
1933 * @gfp_mask: type of allocation
1934 * @type: audit message type
1935 * @fmt: format string to use
1936 * @...: variable parameters matching the format string
1937 *
1938 * This is a convenience function that calls audit_log_start,
1939 * audit_log_vformat, and audit_log_end. It may be called
1940 * in any context.
1941 */
1942void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
1943 const char *fmt, ...)
1944{
1945 struct audit_buffer *ab;
1946 va_list args;
1947
1948 ab = audit_log_start(ctx, gfp_mask, type);
1949 if (ab) {
1950 va_start(args, fmt);
1951 audit_log_vformat(ab, fmt, args);
1952 va_end(args);
1953 audit_log_end(ab);
1954 }
1955}
1956
1957#ifdef CONFIG_SECURITY
1958/**
1959 * audit_log_secctx - Converts and logs SELinux context
1960 * @ab: audit_buffer
1961 * @secid: security number
1962 *
1963 * This is a helper function that calls security_secid_to_secctx to convert
1964 * secid to secctx and then adds the (converted) SELinux context to the audit
1965 * log by calling audit_log_format, thus also preventing leak of internal secid
1966 * to userspace. If secid cannot be converted audit_panic is called.
1967 */
1968void audit_log_secctx(struct audit_buffer *ab, u32 secid)
1969{
1970 u32 len;
1971 char *secctx;
1972
1973 if (security_secid_to_secctx(secid, &secctx, &len)) {
1974 audit_panic("Cannot convert secid to context");
1975 } else {
1976 audit_log_format(ab, " obj=%s", secctx);
1977 security_release_secctx(secctx, len);
1978 }
1979}
1980EXPORT_SYMBOL(audit_log_secctx);
1981#endif
1982
1983EXPORT_SYMBOL(audit_log_start);
1984EXPORT_SYMBOL(audit_log_end);
1985EXPORT_SYMBOL(audit_log_format);
1986EXPORT_SYMBOL(audit_log);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/* audit.c -- Auditing support
3 * Gateway between the kernel (e.g., selinux) and the user-space audit daemon.
4 * System-call specific features have moved to auditsc.c
5 *
6 * Copyright 2003-2007 Red Hat Inc., Durham, North Carolina.
7 * All Rights Reserved.
8 *
9 * Written by Rickard E. (Rik) Faith <faith@redhat.com>
10 *
11 * Goals: 1) Integrate fully with Security Modules.
12 * 2) Minimal run-time overhead:
13 * a) Minimal when syscall auditing is disabled (audit_enable=0).
14 * b) Small when syscall auditing is enabled and no audit record
15 * is generated (defer as much work as possible to record
16 * generation time):
17 * i) context is allocated,
18 * ii) names from getname are stored without a copy, and
19 * iii) inode information stored from path_lookup.
20 * 3) Ability to disable syscall auditing at boot time (audit=0).
21 * 4) Usable by other parts of the kernel (if audit_log* is called,
22 * then a syscall record will be generated automatically for the
23 * current syscall).
24 * 5) Netlink interface to user-space.
25 * 6) Support low-overhead kernel-based filtering to minimize the
26 * information that must be passed to user-space.
27 *
28 * Audit userspace, documentation, tests, and bug/issue trackers:
29 * https://github.com/linux-audit
30 */
31
32#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
33
34#include <linux/file.h>
35#include <linux/init.h>
36#include <linux/types.h>
37#include <linux/atomic.h>
38#include <linux/mm.h>
39#include <linux/export.h>
40#include <linux/slab.h>
41#include <linux/err.h>
42#include <linux/kthread.h>
43#include <linux/kernel.h>
44#include <linux/syscalls.h>
45#include <linux/spinlock.h>
46#include <linux/rcupdate.h>
47#include <linux/mutex.h>
48#include <linux/gfp.h>
49#include <linux/pid.h>
50
51#include <linux/audit.h>
52
53#include <net/sock.h>
54#include <net/netlink.h>
55#include <linux/skbuff.h>
56#include <linux/security.h>
57#include <linux/freezer.h>
58#include <linux/pid_namespace.h>
59#include <net/netns/generic.h>
60
61#include "audit.h"
62
63/* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
64 * (Initialization happens after skb_init is called.) */
65#define AUDIT_DISABLED -1
66#define AUDIT_UNINITIALIZED 0
67#define AUDIT_INITIALIZED 1
68static int audit_initialized = AUDIT_UNINITIALIZED;
69
70u32 audit_enabled = AUDIT_OFF;
71bool audit_ever_enabled = !!AUDIT_OFF;
72
73EXPORT_SYMBOL_GPL(audit_enabled);
74
75/* Default state when kernel boots without any parameters. */
76static u32 audit_default = AUDIT_OFF;
77
78/* If auditing cannot proceed, audit_failure selects what happens. */
79static u32 audit_failure = AUDIT_FAIL_PRINTK;
80
81/* private audit network namespace index */
82static unsigned int audit_net_id;
83
84/**
85 * struct audit_net - audit private network namespace data
86 * @sk: communication socket
87 */
88struct audit_net {
89 struct sock *sk;
90};
91
92/**
93 * struct auditd_connection - kernel/auditd connection state
94 * @pid: auditd PID
95 * @portid: netlink portid
96 * @net: the associated network namespace
97 * @rcu: RCU head
98 *
99 * Description:
100 * This struct is RCU protected; you must either hold the RCU lock for reading
101 * or the associated spinlock for writing.
102 */
103struct auditd_connection {
104 struct pid *pid;
105 u32 portid;
106 struct net *net;
107 struct rcu_head rcu;
108};
109static struct auditd_connection __rcu *auditd_conn;
110static DEFINE_SPINLOCK(auditd_conn_lock);
111
112/* If audit_rate_limit is non-zero, limit the rate of sending audit records
113 * to that number per second. This prevents DoS attacks, but results in
114 * audit records being dropped. */
115static u32 audit_rate_limit;
116
117/* Number of outstanding audit_buffers allowed.
118 * When set to zero, this means unlimited. */
119static u32 audit_backlog_limit = 64;
120#define AUDIT_BACKLOG_WAIT_TIME (60 * HZ)
121static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
122
123/* The identity of the user shutting down the audit system. */
124static kuid_t audit_sig_uid = INVALID_UID;
125static pid_t audit_sig_pid = -1;
126static u32 audit_sig_sid;
127
128/* Records can be lost in several ways:
129 0) [suppressed in audit_alloc]
130 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
131 2) out of memory in audit_log_move [alloc_skb]
132 3) suppressed due to audit_rate_limit
133 4) suppressed due to audit_backlog_limit
134*/
135static atomic_t audit_lost = ATOMIC_INIT(0);
136
137/* Monotonically increasing sum of time the kernel has spent
138 * waiting while the backlog limit is exceeded.
139 */
140static atomic_t audit_backlog_wait_time_actual = ATOMIC_INIT(0);
141
142/* Hash for inode-based rules */
143struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
144
145static struct kmem_cache *audit_buffer_cache;
146
147/* queue msgs to send via kauditd_task */
148static struct sk_buff_head audit_queue;
149/* queue msgs due to temporary unicast send problems */
150static struct sk_buff_head audit_retry_queue;
151/* queue msgs waiting for new auditd connection */
152static struct sk_buff_head audit_hold_queue;
153
154/* queue servicing thread */
155static struct task_struct *kauditd_task;
156static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
157
158/* waitqueue for callers who are blocked on the audit backlog */
159static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
160
161static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION,
162 .mask = -1,
163 .features = 0,
164 .lock = 0,};
165
166static char *audit_feature_names[2] = {
167 "only_unset_loginuid",
168 "loginuid_immutable",
169};
170
171/**
172 * struct audit_ctl_mutex - serialize requests from userspace
173 * @lock: the mutex used for locking
174 * @owner: the task which owns the lock
175 *
176 * Description:
177 * This is the lock struct used to ensure we only process userspace requests
178 * in an orderly fashion. We can't simply use a mutex/lock here because we
179 * need to track lock ownership so we don't end up blocking the lock owner in
180 * audit_log_start() or similar.
181 */
182static struct audit_ctl_mutex {
183 struct mutex lock;
184 void *owner;
185} audit_cmd_mutex;
186
187/* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
188 * audit records. Since printk uses a 1024 byte buffer, this buffer
189 * should be at least that large. */
190#define AUDIT_BUFSIZ 1024
191
192/* The audit_buffer is used when formatting an audit record. The caller
193 * locks briefly to get the record off the freelist or to allocate the
194 * buffer, and locks briefly to send the buffer to the netlink layer or
195 * to place it on a transmit queue. Multiple audit_buffers can be in
196 * use simultaneously. */
197struct audit_buffer {
198 struct sk_buff *skb; /* formatted skb ready to send */
199 struct audit_context *ctx; /* NULL or associated context */
200 gfp_t gfp_mask;
201};
202
203struct audit_reply {
204 __u32 portid;
205 struct net *net;
206 struct sk_buff *skb;
207};
208
209/**
210 * auditd_test_task - Check to see if a given task is an audit daemon
211 * @task: the task to check
212 *
213 * Description:
214 * Return 1 if the task is a registered audit daemon, 0 otherwise.
215 */
216int auditd_test_task(struct task_struct *task)
217{
218 int rc;
219 struct auditd_connection *ac;
220
221 rcu_read_lock();
222 ac = rcu_dereference(auditd_conn);
223 rc = (ac && ac->pid == task_tgid(task) ? 1 : 0);
224 rcu_read_unlock();
225
226 return rc;
227}
228
229/**
230 * audit_ctl_lock - Take the audit control lock
231 */
232void audit_ctl_lock(void)
233{
234 mutex_lock(&audit_cmd_mutex.lock);
235 audit_cmd_mutex.owner = current;
236}
237
238/**
239 * audit_ctl_unlock - Drop the audit control lock
240 */
241void audit_ctl_unlock(void)
242{
243 audit_cmd_mutex.owner = NULL;
244 mutex_unlock(&audit_cmd_mutex.lock);
245}
246
247/**
248 * audit_ctl_owner_current - Test to see if the current task owns the lock
249 *
250 * Description:
251 * Return true if the current task owns the audit control lock, false if it
252 * doesn't own the lock.
253 */
254static bool audit_ctl_owner_current(void)
255{
256 return (current == audit_cmd_mutex.owner);
257}
258
259/**
260 * auditd_pid_vnr - Return the auditd PID relative to the namespace
261 *
262 * Description:
263 * Returns the PID in relation to the namespace, 0 on failure.
264 */
265static pid_t auditd_pid_vnr(void)
266{
267 pid_t pid;
268 const struct auditd_connection *ac;
269
270 rcu_read_lock();
271 ac = rcu_dereference(auditd_conn);
272 if (!ac || !ac->pid)
273 pid = 0;
274 else
275 pid = pid_vnr(ac->pid);
276 rcu_read_unlock();
277
278 return pid;
279}
280
281/**
282 * audit_get_sk - Return the audit socket for the given network namespace
283 * @net: the destination network namespace
284 *
285 * Description:
286 * Returns the sock pointer if valid, NULL otherwise. The caller must ensure
287 * that a reference is held for the network namespace while the sock is in use.
288 */
289static struct sock *audit_get_sk(const struct net *net)
290{
291 struct audit_net *aunet;
292
293 if (!net)
294 return NULL;
295
296 aunet = net_generic(net, audit_net_id);
297 return aunet->sk;
298}
299
300void audit_panic(const char *message)
301{
302 switch (audit_failure) {
303 case AUDIT_FAIL_SILENT:
304 break;
305 case AUDIT_FAIL_PRINTK:
306 if (printk_ratelimit())
307 pr_err("%s\n", message);
308 break;
309 case AUDIT_FAIL_PANIC:
310 panic("audit: %s\n", message);
311 break;
312 }
313}
314
315static inline int audit_rate_check(void)
316{
317 static unsigned long last_check = 0;
318 static int messages = 0;
319 static DEFINE_SPINLOCK(lock);
320 unsigned long flags;
321 unsigned long now;
322 int retval = 0;
323
324 if (!audit_rate_limit)
325 return 1;
326
327 spin_lock_irqsave(&lock, flags);
328 if (++messages < audit_rate_limit) {
329 retval = 1;
330 } else {
331 now = jiffies;
332 if (time_after(now, last_check + HZ)) {
333 last_check = now;
334 messages = 0;
335 retval = 1;
336 }
337 }
338 spin_unlock_irqrestore(&lock, flags);
339
340 return retval;
341}
342
343/**
344 * audit_log_lost - conditionally log lost audit message event
345 * @message: the message stating reason for lost audit message
346 *
347 * Emit at least 1 message per second, even if audit_rate_check is
348 * throttling.
349 * Always increment the lost messages counter.
350*/
351void audit_log_lost(const char *message)
352{
353 static unsigned long last_msg = 0;
354 static DEFINE_SPINLOCK(lock);
355 unsigned long flags;
356 unsigned long now;
357 int print;
358
359 atomic_inc(&audit_lost);
360
361 print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
362
363 if (!print) {
364 spin_lock_irqsave(&lock, flags);
365 now = jiffies;
366 if (time_after(now, last_msg + HZ)) {
367 print = 1;
368 last_msg = now;
369 }
370 spin_unlock_irqrestore(&lock, flags);
371 }
372
373 if (print) {
374 if (printk_ratelimit())
375 pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
376 atomic_read(&audit_lost),
377 audit_rate_limit,
378 audit_backlog_limit);
379 audit_panic(message);
380 }
381}
382
383static int audit_log_config_change(char *function_name, u32 new, u32 old,
384 int allow_changes)
385{
386 struct audit_buffer *ab;
387 int rc = 0;
388
389 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
390 if (unlikely(!ab))
391 return rc;
392 audit_log_format(ab, "op=set %s=%u old=%u ", function_name, new, old);
393 audit_log_session_info(ab);
394 rc = audit_log_task_context(ab);
395 if (rc)
396 allow_changes = 0; /* Something weird, deny request */
397 audit_log_format(ab, " res=%d", allow_changes);
398 audit_log_end(ab);
399 return rc;
400}
401
402static int audit_do_config_change(char *function_name, u32 *to_change, u32 new)
403{
404 int allow_changes, rc = 0;
405 u32 old = *to_change;
406
407 /* check if we are locked */
408 if (audit_enabled == AUDIT_LOCKED)
409 allow_changes = 0;
410 else
411 allow_changes = 1;
412
413 if (audit_enabled != AUDIT_OFF) {
414 rc = audit_log_config_change(function_name, new, old, allow_changes);
415 if (rc)
416 allow_changes = 0;
417 }
418
419 /* If we are allowed, make the change */
420 if (allow_changes == 1)
421 *to_change = new;
422 /* Not allowed, update reason */
423 else if (rc == 0)
424 rc = -EPERM;
425 return rc;
426}
427
428static int audit_set_rate_limit(u32 limit)
429{
430 return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit);
431}
432
433static int audit_set_backlog_limit(u32 limit)
434{
435 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit);
436}
437
438static int audit_set_backlog_wait_time(u32 timeout)
439{
440 return audit_do_config_change("audit_backlog_wait_time",
441 &audit_backlog_wait_time, timeout);
442}
443
444static int audit_set_enabled(u32 state)
445{
446 int rc;
447 if (state > AUDIT_LOCKED)
448 return -EINVAL;
449
450 rc = audit_do_config_change("audit_enabled", &audit_enabled, state);
451 if (!rc)
452 audit_ever_enabled |= !!state;
453
454 return rc;
455}
456
457static int audit_set_failure(u32 state)
458{
459 if (state != AUDIT_FAIL_SILENT
460 && state != AUDIT_FAIL_PRINTK
461 && state != AUDIT_FAIL_PANIC)
462 return -EINVAL;
463
464 return audit_do_config_change("audit_failure", &audit_failure, state);
465}
466
467/**
468 * auditd_conn_free - RCU helper to release an auditd connection struct
469 * @rcu: RCU head
470 *
471 * Description:
472 * Drop any references inside the auditd connection tracking struct and free
473 * the memory.
474 */
475static void auditd_conn_free(struct rcu_head *rcu)
476{
477 struct auditd_connection *ac;
478
479 ac = container_of(rcu, struct auditd_connection, rcu);
480 put_pid(ac->pid);
481 put_net(ac->net);
482 kfree(ac);
483}
484
485/**
486 * auditd_set - Set/Reset the auditd connection state
487 * @pid: auditd PID
488 * @portid: auditd netlink portid
489 * @net: auditd network namespace pointer
490 * @skb: the netlink command from the audit daemon
491 * @ack: netlink ack flag, cleared if ack'd here
492 *
493 * Description:
494 * This function will obtain and drop network namespace references as
495 * necessary. Returns zero on success, negative values on failure.
496 */
497static int auditd_set(struct pid *pid, u32 portid, struct net *net,
498 struct sk_buff *skb, bool *ack)
499{
500 unsigned long flags;
501 struct auditd_connection *ac_old, *ac_new;
502 struct nlmsghdr *nlh;
503
504 if (!pid || !net)
505 return -EINVAL;
506
507 ac_new = kzalloc(sizeof(*ac_new), GFP_KERNEL);
508 if (!ac_new)
509 return -ENOMEM;
510 ac_new->pid = get_pid(pid);
511 ac_new->portid = portid;
512 ac_new->net = get_net(net);
513
514 /* send the ack now to avoid a race with the queue backlog */
515 if (*ack) {
516 nlh = nlmsg_hdr(skb);
517 netlink_ack(skb, nlh, 0, NULL);
518 *ack = false;
519 }
520
521 spin_lock_irqsave(&auditd_conn_lock, flags);
522 ac_old = rcu_dereference_protected(auditd_conn,
523 lockdep_is_held(&auditd_conn_lock));
524 rcu_assign_pointer(auditd_conn, ac_new);
525 spin_unlock_irqrestore(&auditd_conn_lock, flags);
526
527 if (ac_old)
528 call_rcu(&ac_old->rcu, auditd_conn_free);
529
530 return 0;
531}
532
533/**
534 * kauditd_printk_skb - Print the audit record to the ring buffer
535 * @skb: audit record
536 *
537 * Whatever the reason, this packet may not make it to the auditd connection
538 * so write it via printk so the information isn't completely lost.
539 */
540static void kauditd_printk_skb(struct sk_buff *skb)
541{
542 struct nlmsghdr *nlh = nlmsg_hdr(skb);
543 char *data = nlmsg_data(nlh);
544
545 if (nlh->nlmsg_type != AUDIT_EOE && printk_ratelimit())
546 pr_notice("type=%d %s\n", nlh->nlmsg_type, data);
547}
548
549/**
550 * kauditd_rehold_skb - Handle a audit record send failure in the hold queue
551 * @skb: audit record
552 * @error: error code (unused)
553 *
554 * Description:
555 * This should only be used by the kauditd_thread when it fails to flush the
556 * hold queue.
557 */
558static void kauditd_rehold_skb(struct sk_buff *skb, __always_unused int error)
559{
560 /* put the record back in the queue */
561 skb_queue_tail(&audit_hold_queue, skb);
562}
563
564/**
565 * kauditd_hold_skb - Queue an audit record, waiting for auditd
566 * @skb: audit record
567 * @error: error code
568 *
569 * Description:
570 * Queue the audit record, waiting for an instance of auditd. When this
571 * function is called we haven't given up yet on sending the record, but things
572 * are not looking good. The first thing we want to do is try to write the
573 * record via printk and then see if we want to try and hold on to the record
574 * and queue it, if we have room. If we want to hold on to the record, but we
575 * don't have room, record a record lost message.
576 */
577static void kauditd_hold_skb(struct sk_buff *skb, int error)
578{
579 /* at this point it is uncertain if we will ever send this to auditd so
580 * try to send the message via printk before we go any further */
581 kauditd_printk_skb(skb);
582
583 /* can we just silently drop the message? */
584 if (!audit_default)
585 goto drop;
586
587 /* the hold queue is only for when the daemon goes away completely,
588 * not -EAGAIN failures; if we are in a -EAGAIN state requeue the
589 * record on the retry queue unless it's full, in which case drop it
590 */
591 if (error == -EAGAIN) {
592 if (!audit_backlog_limit ||
593 skb_queue_len(&audit_retry_queue) < audit_backlog_limit) {
594 skb_queue_tail(&audit_retry_queue, skb);
595 return;
596 }
597 audit_log_lost("kauditd retry queue overflow");
598 goto drop;
599 }
600
601 /* if we have room in the hold queue, queue the message */
602 if (!audit_backlog_limit ||
603 skb_queue_len(&audit_hold_queue) < audit_backlog_limit) {
604 skb_queue_tail(&audit_hold_queue, skb);
605 return;
606 }
607
608 /* we have no other options - drop the message */
609 audit_log_lost("kauditd hold queue overflow");
610drop:
611 kfree_skb(skb);
612}
613
614/**
615 * kauditd_retry_skb - Queue an audit record, attempt to send again to auditd
616 * @skb: audit record
617 * @error: error code (unused)
618 *
619 * Description:
620 * Not as serious as kauditd_hold_skb() as we still have a connected auditd,
621 * but for some reason we are having problems sending it audit records so
622 * queue the given record and attempt to resend.
623 */
624static void kauditd_retry_skb(struct sk_buff *skb, __always_unused int error)
625{
626 if (!audit_backlog_limit ||
627 skb_queue_len(&audit_retry_queue) < audit_backlog_limit) {
628 skb_queue_tail(&audit_retry_queue, skb);
629 return;
630 }
631
632 /* we have to drop the record, send it via printk as a last effort */
633 kauditd_printk_skb(skb);
634 audit_log_lost("kauditd retry queue overflow");
635 kfree_skb(skb);
636}
637
638/**
639 * auditd_reset - Disconnect the auditd connection
640 * @ac: auditd connection state
641 *
642 * Description:
643 * Break the auditd/kauditd connection and move all the queued records into the
644 * hold queue in case auditd reconnects. It is important to note that the @ac
645 * pointer should never be dereferenced inside this function as it may be NULL
646 * or invalid, you can only compare the memory address! If @ac is NULL then
647 * the connection will always be reset.
648 */
649static void auditd_reset(const struct auditd_connection *ac)
650{
651 unsigned long flags;
652 struct sk_buff *skb;
653 struct auditd_connection *ac_old;
654
655 /* if it isn't already broken, break the connection */
656 spin_lock_irqsave(&auditd_conn_lock, flags);
657 ac_old = rcu_dereference_protected(auditd_conn,
658 lockdep_is_held(&auditd_conn_lock));
659 if (ac && ac != ac_old) {
660 /* someone already registered a new auditd connection */
661 spin_unlock_irqrestore(&auditd_conn_lock, flags);
662 return;
663 }
664 rcu_assign_pointer(auditd_conn, NULL);
665 spin_unlock_irqrestore(&auditd_conn_lock, flags);
666
667 if (ac_old)
668 call_rcu(&ac_old->rcu, auditd_conn_free);
669
670 /* flush the retry queue to the hold queue, but don't touch the main
671 * queue since we need to process that normally for multicast */
672 while ((skb = skb_dequeue(&audit_retry_queue)))
673 kauditd_hold_skb(skb, -ECONNREFUSED);
674}
675
676/**
677 * auditd_send_unicast_skb - Send a record via unicast to auditd
678 * @skb: audit record
679 *
680 * Description:
681 * Send a skb to the audit daemon, returns positive/zero values on success and
682 * negative values on failure; in all cases the skb will be consumed by this
683 * function. If the send results in -ECONNREFUSED the connection with auditd
684 * will be reset. This function may sleep so callers should not hold any locks
685 * where this would cause a problem.
686 */
687static int auditd_send_unicast_skb(struct sk_buff *skb)
688{
689 int rc;
690 u32 portid;
691 struct net *net;
692 struct sock *sk;
693 struct auditd_connection *ac;
694
695 /* NOTE: we can't call netlink_unicast while in the RCU section so
696 * take a reference to the network namespace and grab local
697 * copies of the namespace, the sock, and the portid; the
698 * namespace and sock aren't going to go away while we hold a
699 * reference and if the portid does become invalid after the RCU
700 * section netlink_unicast() should safely return an error */
701
702 rcu_read_lock();
703 ac = rcu_dereference(auditd_conn);
704 if (!ac) {
705 rcu_read_unlock();
706 kfree_skb(skb);
707 rc = -ECONNREFUSED;
708 goto err;
709 }
710 net = get_net(ac->net);
711 sk = audit_get_sk(net);
712 portid = ac->portid;
713 rcu_read_unlock();
714
715 rc = netlink_unicast(sk, skb, portid, 0);
716 put_net(net);
717 if (rc < 0)
718 goto err;
719
720 return rc;
721
722err:
723 if (ac && rc == -ECONNREFUSED)
724 auditd_reset(ac);
725 return rc;
726}
727
728/**
729 * kauditd_send_queue - Helper for kauditd_thread to flush skb queues
730 * @sk: the sending sock
731 * @portid: the netlink destination
732 * @queue: the skb queue to process
733 * @retry_limit: limit on number of netlink unicast failures
734 * @skb_hook: per-skb hook for additional processing
735 * @err_hook: hook called if the skb fails the netlink unicast send
736 *
737 * Description:
738 * Run through the given queue and attempt to send the audit records to auditd,
739 * returns zero on success, negative values on failure. It is up to the caller
740 * to ensure that the @sk is valid for the duration of this function.
741 *
742 */
743static int kauditd_send_queue(struct sock *sk, u32 portid,
744 struct sk_buff_head *queue,
745 unsigned int retry_limit,
746 void (*skb_hook)(struct sk_buff *skb),
747 void (*err_hook)(struct sk_buff *skb, int error))
748{
749 int rc = 0;
750 struct sk_buff *skb = NULL;
751 struct sk_buff *skb_tail;
752 unsigned int failed = 0;
753
754 /* NOTE: kauditd_thread takes care of all our locking, we just use
755 * the netlink info passed to us (e.g. sk and portid) */
756
757 skb_tail = skb_peek_tail(queue);
758 while ((skb != skb_tail) && (skb = skb_dequeue(queue))) {
759 /* call the skb_hook for each skb we touch */
760 if (skb_hook)
761 (*skb_hook)(skb);
762
763 /* can we send to anyone via unicast? */
764 if (!sk) {
765 if (err_hook)
766 (*err_hook)(skb, -ECONNREFUSED);
767 continue;
768 }
769
770retry:
771 /* grab an extra skb reference in case of error */
772 skb_get(skb);
773 rc = netlink_unicast(sk, skb, portid, 0);
774 if (rc < 0) {
775 /* send failed - try a few times unless fatal error */
776 if (++failed >= retry_limit ||
777 rc == -ECONNREFUSED || rc == -EPERM) {
778 sk = NULL;
779 if (err_hook)
780 (*err_hook)(skb, rc);
781 if (rc == -EAGAIN)
782 rc = 0;
783 /* continue to drain the queue */
784 continue;
785 } else
786 goto retry;
787 } else {
788 /* skb sent - drop the extra reference and continue */
789 consume_skb(skb);
790 failed = 0;
791 }
792 }
793
794 return (rc >= 0 ? 0 : rc);
795}
796
797/*
798 * kauditd_send_multicast_skb - Send a record to any multicast listeners
799 * @skb: audit record
800 *
801 * Description:
802 * Write a multicast message to anyone listening in the initial network
803 * namespace. This function doesn't consume an skb as might be expected since
804 * it has to copy it anyways.
805 */
806static void kauditd_send_multicast_skb(struct sk_buff *skb)
807{
808 struct sk_buff *copy;
809 struct sock *sock = audit_get_sk(&init_net);
810 struct nlmsghdr *nlh;
811
812 /* NOTE: we are not taking an additional reference for init_net since
813 * we don't have to worry about it going away */
814
815 if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
816 return;
817
818 /*
819 * The seemingly wasteful skb_copy() rather than bumping the refcount
820 * using skb_get() is necessary because non-standard mods are made to
821 * the skb by the original kaudit unicast socket send routine. The
822 * existing auditd daemon assumes this breakage. Fixing this would
823 * require co-ordinating a change in the established protocol between
824 * the kaudit kernel subsystem and the auditd userspace code. There is
825 * no reason for new multicast clients to continue with this
826 * non-compliance.
827 */
828 copy = skb_copy(skb, GFP_KERNEL);
829 if (!copy)
830 return;
831 nlh = nlmsg_hdr(copy);
832 nlh->nlmsg_len = skb->len;
833
834 nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL);
835}
836
837/**
838 * kauditd_thread - Worker thread to send audit records to userspace
839 * @dummy: unused
840 */
841static int kauditd_thread(void *dummy)
842{
843 int rc;
844 u32 portid = 0;
845 struct net *net = NULL;
846 struct sock *sk = NULL;
847 struct auditd_connection *ac;
848
849#define UNICAST_RETRIES 5
850
851 set_freezable();
852 while (!kthread_should_stop()) {
853 /* NOTE: see the lock comments in auditd_send_unicast_skb() */
854 rcu_read_lock();
855 ac = rcu_dereference(auditd_conn);
856 if (!ac) {
857 rcu_read_unlock();
858 goto main_queue;
859 }
860 net = get_net(ac->net);
861 sk = audit_get_sk(net);
862 portid = ac->portid;
863 rcu_read_unlock();
864
865 /* attempt to flush the hold queue */
866 rc = kauditd_send_queue(sk, portid,
867 &audit_hold_queue, UNICAST_RETRIES,
868 NULL, kauditd_rehold_skb);
869 if (rc < 0) {
870 sk = NULL;
871 auditd_reset(ac);
872 goto main_queue;
873 }
874
875 /* attempt to flush the retry queue */
876 rc = kauditd_send_queue(sk, portid,
877 &audit_retry_queue, UNICAST_RETRIES,
878 NULL, kauditd_hold_skb);
879 if (rc < 0) {
880 sk = NULL;
881 auditd_reset(ac);
882 goto main_queue;
883 }
884
885main_queue:
886 /* process the main queue - do the multicast send and attempt
887 * unicast, dump failed record sends to the retry queue; if
888 * sk == NULL due to previous failures we will just do the
889 * multicast send and move the record to the hold queue */
890 rc = kauditd_send_queue(sk, portid, &audit_queue, 1,
891 kauditd_send_multicast_skb,
892 (sk ?
893 kauditd_retry_skb : kauditd_hold_skb));
894 if (ac && rc < 0)
895 auditd_reset(ac);
896 sk = NULL;
897
898 /* drop our netns reference, no auditd sends past this line */
899 if (net) {
900 put_net(net);
901 net = NULL;
902 }
903
904 /* we have processed all the queues so wake everyone */
905 wake_up(&audit_backlog_wait);
906
907 /* NOTE: we want to wake up if there is anything on the queue,
908 * regardless of if an auditd is connected, as we need to
909 * do the multicast send and rotate records from the
910 * main queue to the retry/hold queues */
911 wait_event_freezable(kauditd_wait,
912 (skb_queue_len(&audit_queue) ? 1 : 0));
913 }
914
915 return 0;
916}
917
918int audit_send_list_thread(void *_dest)
919{
920 struct audit_netlink_list *dest = _dest;
921 struct sk_buff *skb;
922 struct sock *sk = audit_get_sk(dest->net);
923
924 /* wait for parent to finish and send an ACK */
925 audit_ctl_lock();
926 audit_ctl_unlock();
927
928 while ((skb = __skb_dequeue(&dest->q)) != NULL)
929 netlink_unicast(sk, skb, dest->portid, 0);
930
931 put_net(dest->net);
932 kfree(dest);
933
934 return 0;
935}
936
937struct sk_buff *audit_make_reply(int seq, int type, int done,
938 int multi, const void *payload, int size)
939{
940 struct sk_buff *skb;
941 struct nlmsghdr *nlh;
942 void *data;
943 int flags = multi ? NLM_F_MULTI : 0;
944 int t = done ? NLMSG_DONE : type;
945
946 skb = nlmsg_new(size, GFP_KERNEL);
947 if (!skb)
948 return NULL;
949
950 nlh = nlmsg_put(skb, 0, seq, t, size, flags);
951 if (!nlh)
952 goto out_kfree_skb;
953 data = nlmsg_data(nlh);
954 memcpy(data, payload, size);
955 return skb;
956
957out_kfree_skb:
958 kfree_skb(skb);
959 return NULL;
960}
961
962static void audit_free_reply(struct audit_reply *reply)
963{
964 if (!reply)
965 return;
966
967 kfree_skb(reply->skb);
968 if (reply->net)
969 put_net(reply->net);
970 kfree(reply);
971}
972
973static int audit_send_reply_thread(void *arg)
974{
975 struct audit_reply *reply = (struct audit_reply *)arg;
976
977 audit_ctl_lock();
978 audit_ctl_unlock();
979
980 /* Ignore failure. It'll only happen if the sender goes away,
981 because our timeout is set to infinite. */
982 netlink_unicast(audit_get_sk(reply->net), reply->skb, reply->portid, 0);
983 reply->skb = NULL;
984 audit_free_reply(reply);
985 return 0;
986}
987
988/**
989 * audit_send_reply - send an audit reply message via netlink
990 * @request_skb: skb of request we are replying to (used to target the reply)
991 * @seq: sequence number
992 * @type: audit message type
993 * @done: done (last) flag
994 * @multi: multi-part message flag
995 * @payload: payload data
996 * @size: payload size
997 *
998 * Allocates a skb, builds the netlink message, and sends it to the port id.
999 */
1000static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
1001 int multi, const void *payload, int size)
1002{
1003 struct task_struct *tsk;
1004 struct audit_reply *reply;
1005
1006 reply = kzalloc(sizeof(*reply), GFP_KERNEL);
1007 if (!reply)
1008 return;
1009
1010 reply->skb = audit_make_reply(seq, type, done, multi, payload, size);
1011 if (!reply->skb)
1012 goto err;
1013 reply->net = get_net(sock_net(NETLINK_CB(request_skb).sk));
1014 reply->portid = NETLINK_CB(request_skb).portid;
1015
1016 tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
1017 if (IS_ERR(tsk))
1018 goto err;
1019
1020 return;
1021
1022err:
1023 audit_free_reply(reply);
1024}
1025
1026/*
1027 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
1028 * control messages.
1029 */
1030static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
1031{
1032 int err = 0;
1033
1034 /* Only support initial user namespace for now. */
1035 /*
1036 * We return ECONNREFUSED because it tricks userspace into thinking
1037 * that audit was not configured into the kernel. Lots of users
1038 * configure their PAM stack (because that's what the distro does)
1039 * to reject login if unable to send messages to audit. If we return
1040 * ECONNREFUSED the PAM stack thinks the kernel does not have audit
1041 * configured in and will let login proceed. If we return EPERM
1042 * userspace will reject all logins. This should be removed when we
1043 * support non init namespaces!!
1044 */
1045 if (current_user_ns() != &init_user_ns)
1046 return -ECONNREFUSED;
1047
1048 switch (msg_type) {
1049 case AUDIT_LIST:
1050 case AUDIT_ADD:
1051 case AUDIT_DEL:
1052 return -EOPNOTSUPP;
1053 case AUDIT_GET:
1054 case AUDIT_SET:
1055 case AUDIT_GET_FEATURE:
1056 case AUDIT_SET_FEATURE:
1057 case AUDIT_LIST_RULES:
1058 case AUDIT_ADD_RULE:
1059 case AUDIT_DEL_RULE:
1060 case AUDIT_SIGNAL_INFO:
1061 case AUDIT_TTY_GET:
1062 case AUDIT_TTY_SET:
1063 case AUDIT_TRIM:
1064 case AUDIT_MAKE_EQUIV:
1065 /* Only support auditd and auditctl in initial pid namespace
1066 * for now. */
1067 if (task_active_pid_ns(current) != &init_pid_ns)
1068 return -EPERM;
1069
1070 if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
1071 err = -EPERM;
1072 break;
1073 case AUDIT_USER:
1074 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1075 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1076 if (!netlink_capable(skb, CAP_AUDIT_WRITE))
1077 err = -EPERM;
1078 break;
1079 default: /* bad msg */
1080 err = -EINVAL;
1081 }
1082
1083 return err;
1084}
1085
1086static void audit_log_common_recv_msg(struct audit_context *context,
1087 struct audit_buffer **ab, u16 msg_type)
1088{
1089 uid_t uid = from_kuid(&init_user_ns, current_uid());
1090 pid_t pid = task_tgid_nr(current);
1091
1092 if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
1093 *ab = NULL;
1094 return;
1095 }
1096
1097 *ab = audit_log_start(context, GFP_KERNEL, msg_type);
1098 if (unlikely(!*ab))
1099 return;
1100 audit_log_format(*ab, "pid=%d uid=%u ", pid, uid);
1101 audit_log_session_info(*ab);
1102 audit_log_task_context(*ab);
1103}
1104
1105static inline void audit_log_user_recv_msg(struct audit_buffer **ab,
1106 u16 msg_type)
1107{
1108 audit_log_common_recv_msg(NULL, ab, msg_type);
1109}
1110
1111static int is_audit_feature_set(int i)
1112{
1113 return af.features & AUDIT_FEATURE_TO_MASK(i);
1114}
1115
1116
1117static int audit_get_feature(struct sk_buff *skb)
1118{
1119 u32 seq;
1120
1121 seq = nlmsg_hdr(skb)->nlmsg_seq;
1122
1123 audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af));
1124
1125 return 0;
1126}
1127
1128static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
1129 u32 old_lock, u32 new_lock, int res)
1130{
1131 struct audit_buffer *ab;
1132
1133 if (audit_enabled == AUDIT_OFF)
1134 return;
1135
1136 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_FEATURE_CHANGE);
1137 if (!ab)
1138 return;
1139 audit_log_task_info(ab);
1140 audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
1141 audit_feature_names[which], !!old_feature, !!new_feature,
1142 !!old_lock, !!new_lock, res);
1143 audit_log_end(ab);
1144}
1145
1146static int audit_set_feature(struct audit_features *uaf)
1147{
1148 int i;
1149
1150 BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
1151
1152 /* if there is ever a version 2 we should handle that here */
1153
1154 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1155 u32 feature = AUDIT_FEATURE_TO_MASK(i);
1156 u32 old_feature, new_feature, old_lock, new_lock;
1157
1158 /* if we are not changing this feature, move along */
1159 if (!(feature & uaf->mask))
1160 continue;
1161
1162 old_feature = af.features & feature;
1163 new_feature = uaf->features & feature;
1164 new_lock = (uaf->lock | af.lock) & feature;
1165 old_lock = af.lock & feature;
1166
1167 /* are we changing a locked feature? */
1168 if (old_lock && (new_feature != old_feature)) {
1169 audit_log_feature_change(i, old_feature, new_feature,
1170 old_lock, new_lock, 0);
1171 return -EPERM;
1172 }
1173 }
1174 /* nothing invalid, do the changes */
1175 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1176 u32 feature = AUDIT_FEATURE_TO_MASK(i);
1177 u32 old_feature, new_feature, old_lock, new_lock;
1178
1179 /* if we are not changing this feature, move along */
1180 if (!(feature & uaf->mask))
1181 continue;
1182
1183 old_feature = af.features & feature;
1184 new_feature = uaf->features & feature;
1185 old_lock = af.lock & feature;
1186 new_lock = (uaf->lock | af.lock) & feature;
1187
1188 if (new_feature != old_feature)
1189 audit_log_feature_change(i, old_feature, new_feature,
1190 old_lock, new_lock, 1);
1191
1192 if (new_feature)
1193 af.features |= feature;
1194 else
1195 af.features &= ~feature;
1196 af.lock |= new_lock;
1197 }
1198
1199 return 0;
1200}
1201
1202static int audit_replace(struct pid *pid)
1203{
1204 pid_t pvnr;
1205 struct sk_buff *skb;
1206
1207 pvnr = pid_vnr(pid);
1208 skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pvnr, sizeof(pvnr));
1209 if (!skb)
1210 return -ENOMEM;
1211 return auditd_send_unicast_skb(skb);
1212}
1213
1214static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
1215 bool *ack)
1216{
1217 u32 seq;
1218 void *data;
1219 int data_len;
1220 int err;
1221 struct audit_buffer *ab;
1222 u16 msg_type = nlh->nlmsg_type;
1223 struct audit_sig_info *sig_data;
1224 char *ctx = NULL;
1225 u32 len;
1226
1227 err = audit_netlink_ok(skb, msg_type);
1228 if (err)
1229 return err;
1230
1231 seq = nlh->nlmsg_seq;
1232 data = nlmsg_data(nlh);
1233 data_len = nlmsg_len(nlh);
1234
1235 switch (msg_type) {
1236 case AUDIT_GET: {
1237 struct audit_status s;
1238 memset(&s, 0, sizeof(s));
1239 s.enabled = audit_enabled;
1240 s.failure = audit_failure;
1241 /* NOTE: use pid_vnr() so the PID is relative to the current
1242 * namespace */
1243 s.pid = auditd_pid_vnr();
1244 s.rate_limit = audit_rate_limit;
1245 s.backlog_limit = audit_backlog_limit;
1246 s.lost = atomic_read(&audit_lost);
1247 s.backlog = skb_queue_len(&audit_queue);
1248 s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL;
1249 s.backlog_wait_time = audit_backlog_wait_time;
1250 s.backlog_wait_time_actual = atomic_read(&audit_backlog_wait_time_actual);
1251 audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
1252 break;
1253 }
1254 case AUDIT_SET: {
1255 struct audit_status s;
1256 memset(&s, 0, sizeof(s));
1257 /* guard against past and future API changes */
1258 memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
1259 if (s.mask & AUDIT_STATUS_ENABLED) {
1260 err = audit_set_enabled(s.enabled);
1261 if (err < 0)
1262 return err;
1263 }
1264 if (s.mask & AUDIT_STATUS_FAILURE) {
1265 err = audit_set_failure(s.failure);
1266 if (err < 0)
1267 return err;
1268 }
1269 if (s.mask & AUDIT_STATUS_PID) {
1270 /* NOTE: we are using the vnr PID functions below
1271 * because the s.pid value is relative to the
1272 * namespace of the caller; at present this
1273 * doesn't matter much since you can really only
1274 * run auditd from the initial pid namespace, but
1275 * something to keep in mind if this changes */
1276 pid_t new_pid = s.pid;
1277 pid_t auditd_pid;
1278 struct pid *req_pid = task_tgid(current);
1279
1280 /* Sanity check - PID values must match. Setting
1281 * pid to 0 is how auditd ends auditing. */
1282 if (new_pid && (new_pid != pid_vnr(req_pid)))
1283 return -EINVAL;
1284
1285 /* test the auditd connection */
1286 audit_replace(req_pid);
1287
1288 auditd_pid = auditd_pid_vnr();
1289 if (auditd_pid) {
1290 /* replacing a healthy auditd is not allowed */
1291 if (new_pid) {
1292 audit_log_config_change("audit_pid",
1293 new_pid, auditd_pid, 0);
1294 return -EEXIST;
1295 }
1296 /* only current auditd can unregister itself */
1297 if (pid_vnr(req_pid) != auditd_pid) {
1298 audit_log_config_change("audit_pid",
1299 new_pid, auditd_pid, 0);
1300 return -EACCES;
1301 }
1302 }
1303
1304 if (new_pid) {
1305 /* register a new auditd connection */
1306 err = auditd_set(req_pid,
1307 NETLINK_CB(skb).portid,
1308 sock_net(NETLINK_CB(skb).sk),
1309 skb, ack);
1310 if (audit_enabled != AUDIT_OFF)
1311 audit_log_config_change("audit_pid",
1312 new_pid,
1313 auditd_pid,
1314 err ? 0 : 1);
1315 if (err)
1316 return err;
1317
1318 /* try to process any backlog */
1319 wake_up_interruptible(&kauditd_wait);
1320 } else {
1321 if (audit_enabled != AUDIT_OFF)
1322 audit_log_config_change("audit_pid",
1323 new_pid,
1324 auditd_pid, 1);
1325
1326 /* unregister the auditd connection */
1327 auditd_reset(NULL);
1328 }
1329 }
1330 if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
1331 err = audit_set_rate_limit(s.rate_limit);
1332 if (err < 0)
1333 return err;
1334 }
1335 if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
1336 err = audit_set_backlog_limit(s.backlog_limit);
1337 if (err < 0)
1338 return err;
1339 }
1340 if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
1341 if (sizeof(s) > (size_t)nlh->nlmsg_len)
1342 return -EINVAL;
1343 if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
1344 return -EINVAL;
1345 err = audit_set_backlog_wait_time(s.backlog_wait_time);
1346 if (err < 0)
1347 return err;
1348 }
1349 if (s.mask == AUDIT_STATUS_LOST) {
1350 u32 lost = atomic_xchg(&audit_lost, 0);
1351
1352 audit_log_config_change("lost", 0, lost, 1);
1353 return lost;
1354 }
1355 if (s.mask == AUDIT_STATUS_BACKLOG_WAIT_TIME_ACTUAL) {
1356 u32 actual = atomic_xchg(&audit_backlog_wait_time_actual, 0);
1357
1358 audit_log_config_change("backlog_wait_time_actual", 0, actual, 1);
1359 return actual;
1360 }
1361 break;
1362 }
1363 case AUDIT_GET_FEATURE:
1364 err = audit_get_feature(skb);
1365 if (err)
1366 return err;
1367 break;
1368 case AUDIT_SET_FEATURE:
1369 if (data_len < sizeof(struct audit_features))
1370 return -EINVAL;
1371 err = audit_set_feature(data);
1372 if (err)
1373 return err;
1374 break;
1375 case AUDIT_USER:
1376 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1377 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1378 if (!audit_enabled && msg_type != AUDIT_USER_AVC)
1379 return 0;
1380 /* exit early if there isn't at least one character to print */
1381 if (data_len < 2)
1382 return -EINVAL;
1383
1384 err = audit_filter(msg_type, AUDIT_FILTER_USER);
1385 if (err == 1) { /* match or error */
1386 char *str = data;
1387
1388 err = 0;
1389 if (msg_type == AUDIT_USER_TTY) {
1390 err = tty_audit_push();
1391 if (err)
1392 break;
1393 }
1394 audit_log_user_recv_msg(&ab, msg_type);
1395 if (msg_type != AUDIT_USER_TTY) {
1396 /* ensure NULL termination */
1397 str[data_len - 1] = '\0';
1398 audit_log_format(ab, " msg='%.*s'",
1399 AUDIT_MESSAGE_TEXT_MAX,
1400 str);
1401 } else {
1402 audit_log_format(ab, " data=");
1403 if (str[data_len - 1] == '\0')
1404 data_len--;
1405 audit_log_n_untrustedstring(ab, str, data_len);
1406 }
1407 audit_log_end(ab);
1408 }
1409 break;
1410 case AUDIT_ADD_RULE:
1411 case AUDIT_DEL_RULE:
1412 if (data_len < sizeof(struct audit_rule_data))
1413 return -EINVAL;
1414 if (audit_enabled == AUDIT_LOCKED) {
1415 audit_log_common_recv_msg(audit_context(), &ab,
1416 AUDIT_CONFIG_CHANGE);
1417 audit_log_format(ab, " op=%s audit_enabled=%d res=0",
1418 msg_type == AUDIT_ADD_RULE ?
1419 "add_rule" : "remove_rule",
1420 audit_enabled);
1421 audit_log_end(ab);
1422 return -EPERM;
1423 }
1424 err = audit_rule_change(msg_type, seq, data, data_len);
1425 break;
1426 case AUDIT_LIST_RULES:
1427 err = audit_list_rules_send(skb, seq);
1428 break;
1429 case AUDIT_TRIM:
1430 audit_trim_trees();
1431 audit_log_common_recv_msg(audit_context(), &ab,
1432 AUDIT_CONFIG_CHANGE);
1433 audit_log_format(ab, " op=trim res=1");
1434 audit_log_end(ab);
1435 break;
1436 case AUDIT_MAKE_EQUIV: {
1437 void *bufp = data;
1438 u32 sizes[2];
1439 size_t msglen = data_len;
1440 char *old, *new;
1441
1442 err = -EINVAL;
1443 if (msglen < 2 * sizeof(u32))
1444 break;
1445 memcpy(sizes, bufp, 2 * sizeof(u32));
1446 bufp += 2 * sizeof(u32);
1447 msglen -= 2 * sizeof(u32);
1448 old = audit_unpack_string(&bufp, &msglen, sizes[0]);
1449 if (IS_ERR(old)) {
1450 err = PTR_ERR(old);
1451 break;
1452 }
1453 new = audit_unpack_string(&bufp, &msglen, sizes[1]);
1454 if (IS_ERR(new)) {
1455 err = PTR_ERR(new);
1456 kfree(old);
1457 break;
1458 }
1459 /* OK, here comes... */
1460 err = audit_tag_tree(old, new);
1461
1462 audit_log_common_recv_msg(audit_context(), &ab,
1463 AUDIT_CONFIG_CHANGE);
1464 audit_log_format(ab, " op=make_equiv old=");
1465 audit_log_untrustedstring(ab, old);
1466 audit_log_format(ab, " new=");
1467 audit_log_untrustedstring(ab, new);
1468 audit_log_format(ab, " res=%d", !err);
1469 audit_log_end(ab);
1470 kfree(old);
1471 kfree(new);
1472 break;
1473 }
1474 case AUDIT_SIGNAL_INFO:
1475 len = 0;
1476 if (audit_sig_sid) {
1477 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
1478 if (err)
1479 return err;
1480 }
1481 sig_data = kmalloc(struct_size(sig_data, ctx, len), GFP_KERNEL);
1482 if (!sig_data) {
1483 if (audit_sig_sid)
1484 security_release_secctx(ctx, len);
1485 return -ENOMEM;
1486 }
1487 sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
1488 sig_data->pid = audit_sig_pid;
1489 if (audit_sig_sid) {
1490 memcpy(sig_data->ctx, ctx, len);
1491 security_release_secctx(ctx, len);
1492 }
1493 audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
1494 sig_data, struct_size(sig_data, ctx, len));
1495 kfree(sig_data);
1496 break;
1497 case AUDIT_TTY_GET: {
1498 struct audit_tty_status s;
1499 unsigned int t;
1500
1501 t = READ_ONCE(current->signal->audit_tty);
1502 s.enabled = t & AUDIT_TTY_ENABLE;
1503 s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1504
1505 audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
1506 break;
1507 }
1508 case AUDIT_TTY_SET: {
1509 struct audit_tty_status s, old;
1510 struct audit_buffer *ab;
1511 unsigned int t;
1512
1513 memset(&s, 0, sizeof(s));
1514 /* guard against past and future API changes */
1515 memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
1516 /* check if new data is valid */
1517 if ((s.enabled != 0 && s.enabled != 1) ||
1518 (s.log_passwd != 0 && s.log_passwd != 1))
1519 err = -EINVAL;
1520
1521 if (err)
1522 t = READ_ONCE(current->signal->audit_tty);
1523 else {
1524 t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD);
1525 t = xchg(¤t->signal->audit_tty, t);
1526 }
1527 old.enabled = t & AUDIT_TTY_ENABLE;
1528 old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1529
1530 audit_log_common_recv_msg(audit_context(), &ab,
1531 AUDIT_CONFIG_CHANGE);
1532 audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
1533 " old-log_passwd=%d new-log_passwd=%d res=%d",
1534 old.enabled, s.enabled, old.log_passwd,
1535 s.log_passwd, !err);
1536 audit_log_end(ab);
1537 break;
1538 }
1539 default:
1540 err = -EINVAL;
1541 break;
1542 }
1543
1544 return err < 0 ? err : 0;
1545}
1546
1547/**
1548 * audit_receive - receive messages from a netlink control socket
1549 * @skb: the message buffer
1550 *
1551 * Parse the provided skb and deal with any messages that may be present,
1552 * malformed skbs are discarded.
1553 */
1554static void audit_receive(struct sk_buff *skb)
1555{
1556 struct nlmsghdr *nlh;
1557 bool ack;
1558 /*
1559 * len MUST be signed for nlmsg_next to be able to dec it below 0
1560 * if the nlmsg_len was not aligned
1561 */
1562 int len;
1563 int err;
1564
1565 nlh = nlmsg_hdr(skb);
1566 len = skb->len;
1567
1568 audit_ctl_lock();
1569 while (nlmsg_ok(nlh, len)) {
1570 ack = nlh->nlmsg_flags & NLM_F_ACK;
1571 err = audit_receive_msg(skb, nlh, &ack);
1572
1573 /* send an ack if the user asked for one and audit_receive_msg
1574 * didn't already do it, or if there was an error. */
1575 if (ack || err)
1576 netlink_ack(skb, nlh, err, NULL);
1577
1578 nlh = nlmsg_next(nlh, &len);
1579 }
1580 audit_ctl_unlock();
1581
1582 /* can't block with the ctrl lock, so penalize the sender now */
1583 if (audit_backlog_limit &&
1584 (skb_queue_len(&audit_queue) > audit_backlog_limit)) {
1585 DECLARE_WAITQUEUE(wait, current);
1586
1587 /* wake kauditd to try and flush the queue */
1588 wake_up_interruptible(&kauditd_wait);
1589
1590 add_wait_queue_exclusive(&audit_backlog_wait, &wait);
1591 set_current_state(TASK_UNINTERRUPTIBLE);
1592 schedule_timeout(audit_backlog_wait_time);
1593 remove_wait_queue(&audit_backlog_wait, &wait);
1594 }
1595}
1596
1597/* Log information about who is connecting to the audit multicast socket */
1598static void audit_log_multicast(int group, const char *op, int err)
1599{
1600 const struct cred *cred;
1601 struct tty_struct *tty;
1602 char comm[sizeof(current->comm)];
1603 struct audit_buffer *ab;
1604
1605 if (!audit_enabled)
1606 return;
1607
1608 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_EVENT_LISTENER);
1609 if (!ab)
1610 return;
1611
1612 cred = current_cred();
1613 tty = audit_get_tty();
1614 audit_log_format(ab, "pid=%u uid=%u auid=%u tty=%s ses=%u",
1615 task_pid_nr(current),
1616 from_kuid(&init_user_ns, cred->uid),
1617 from_kuid(&init_user_ns, audit_get_loginuid(current)),
1618 tty ? tty_name(tty) : "(none)",
1619 audit_get_sessionid(current));
1620 audit_put_tty(tty);
1621 audit_log_task_context(ab); /* subj= */
1622 audit_log_format(ab, " comm=");
1623 audit_log_untrustedstring(ab, get_task_comm(comm, current));
1624 audit_log_d_path_exe(ab, current->mm); /* exe= */
1625 audit_log_format(ab, " nl-mcgrp=%d op=%s res=%d", group, op, !err);
1626 audit_log_end(ab);
1627}
1628
1629/* Run custom bind function on netlink socket group connect or bind requests. */
1630static int audit_multicast_bind(struct net *net, int group)
1631{
1632 int err = 0;
1633
1634 if (!capable(CAP_AUDIT_READ))
1635 err = -EPERM;
1636 audit_log_multicast(group, "connect", err);
1637 return err;
1638}
1639
1640static void audit_multicast_unbind(struct net *net, int group)
1641{
1642 audit_log_multicast(group, "disconnect", 0);
1643}
1644
1645static int __net_init audit_net_init(struct net *net)
1646{
1647 struct netlink_kernel_cfg cfg = {
1648 .input = audit_receive,
1649 .bind = audit_multicast_bind,
1650 .unbind = audit_multicast_unbind,
1651 .flags = NL_CFG_F_NONROOT_RECV,
1652 .groups = AUDIT_NLGRP_MAX,
1653 };
1654
1655 struct audit_net *aunet = net_generic(net, audit_net_id);
1656
1657 aunet->sk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
1658 if (aunet->sk == NULL) {
1659 audit_panic("cannot initialize netlink socket in namespace");
1660 return -ENOMEM;
1661 }
1662 /* limit the timeout in case auditd is blocked/stopped */
1663 aunet->sk->sk_sndtimeo = HZ / 10;
1664
1665 return 0;
1666}
1667
1668static void __net_exit audit_net_exit(struct net *net)
1669{
1670 struct audit_net *aunet = net_generic(net, audit_net_id);
1671
1672 /* NOTE: you would think that we would want to check the auditd
1673 * connection and potentially reset it here if it lives in this
1674 * namespace, but since the auditd connection tracking struct holds a
1675 * reference to this namespace (see auditd_set()) we are only ever
1676 * going to get here after that connection has been released */
1677
1678 netlink_kernel_release(aunet->sk);
1679}
1680
1681static struct pernet_operations audit_net_ops __net_initdata = {
1682 .init = audit_net_init,
1683 .exit = audit_net_exit,
1684 .id = &audit_net_id,
1685 .size = sizeof(struct audit_net),
1686};
1687
1688/* Initialize audit support at boot time. */
1689static int __init audit_init(void)
1690{
1691 int i;
1692
1693 if (audit_initialized == AUDIT_DISABLED)
1694 return 0;
1695
1696 audit_buffer_cache = kmem_cache_create("audit_buffer",
1697 sizeof(struct audit_buffer),
1698 0, SLAB_PANIC, NULL);
1699
1700 skb_queue_head_init(&audit_queue);
1701 skb_queue_head_init(&audit_retry_queue);
1702 skb_queue_head_init(&audit_hold_queue);
1703
1704 for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
1705 INIT_LIST_HEAD(&audit_inode_hash[i]);
1706
1707 mutex_init(&audit_cmd_mutex.lock);
1708 audit_cmd_mutex.owner = NULL;
1709
1710 pr_info("initializing netlink subsys (%s)\n",
1711 audit_default ? "enabled" : "disabled");
1712 register_pernet_subsys(&audit_net_ops);
1713
1714 audit_initialized = AUDIT_INITIALIZED;
1715
1716 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
1717 if (IS_ERR(kauditd_task)) {
1718 int err = PTR_ERR(kauditd_task);
1719 panic("audit: failed to start the kauditd thread (%d)\n", err);
1720 }
1721
1722 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL,
1723 "state=initialized audit_enabled=%u res=1",
1724 audit_enabled);
1725
1726 return 0;
1727}
1728postcore_initcall(audit_init);
1729
1730/*
1731 * Process kernel command-line parameter at boot time.
1732 * audit={0|off} or audit={1|on}.
1733 */
1734static int __init audit_enable(char *str)
1735{
1736 if (!strcasecmp(str, "off") || !strcmp(str, "0"))
1737 audit_default = AUDIT_OFF;
1738 else if (!strcasecmp(str, "on") || !strcmp(str, "1"))
1739 audit_default = AUDIT_ON;
1740 else {
1741 pr_err("audit: invalid 'audit' parameter value (%s)\n", str);
1742 audit_default = AUDIT_ON;
1743 }
1744
1745 if (audit_default == AUDIT_OFF)
1746 audit_initialized = AUDIT_DISABLED;
1747 if (audit_set_enabled(audit_default))
1748 pr_err("audit: error setting audit state (%d)\n",
1749 audit_default);
1750
1751 pr_info("%s\n", audit_default ?
1752 "enabled (after initialization)" : "disabled (until reboot)");
1753
1754 return 1;
1755}
1756__setup("audit=", audit_enable);
1757
1758/* Process kernel command-line parameter at boot time.
1759 * audit_backlog_limit=<n> */
1760static int __init audit_backlog_limit_set(char *str)
1761{
1762 u32 audit_backlog_limit_arg;
1763
1764 pr_info("audit_backlog_limit: ");
1765 if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
1766 pr_cont("using default of %u, unable to parse %s\n",
1767 audit_backlog_limit, str);
1768 return 1;
1769 }
1770
1771 audit_backlog_limit = audit_backlog_limit_arg;
1772 pr_cont("%d\n", audit_backlog_limit);
1773
1774 return 1;
1775}
1776__setup("audit_backlog_limit=", audit_backlog_limit_set);
1777
1778static void audit_buffer_free(struct audit_buffer *ab)
1779{
1780 if (!ab)
1781 return;
1782
1783 kfree_skb(ab->skb);
1784 kmem_cache_free(audit_buffer_cache, ab);
1785}
1786
1787static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx,
1788 gfp_t gfp_mask, int type)
1789{
1790 struct audit_buffer *ab;
1791
1792 ab = kmem_cache_alloc(audit_buffer_cache, gfp_mask);
1793 if (!ab)
1794 return NULL;
1795
1796 ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
1797 if (!ab->skb)
1798 goto err;
1799 if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0))
1800 goto err;
1801
1802 ab->ctx = ctx;
1803 ab->gfp_mask = gfp_mask;
1804
1805 return ab;
1806
1807err:
1808 audit_buffer_free(ab);
1809 return NULL;
1810}
1811
1812/**
1813 * audit_serial - compute a serial number for the audit record
1814 *
1815 * Compute a serial number for the audit record. Audit records are
1816 * written to user-space as soon as they are generated, so a complete
1817 * audit record may be written in several pieces. The timestamp of the
1818 * record and this serial number are used by the user-space tools to
1819 * determine which pieces belong to the same audit record. The
1820 * (timestamp,serial) tuple is unique for each syscall and is live from
1821 * syscall entry to syscall exit.
1822 *
1823 * NOTE: Another possibility is to store the formatted records off the
1824 * audit context (for those records that have a context), and emit them
1825 * all at syscall exit. However, this could delay the reporting of
1826 * significant errors until syscall exit (or never, if the system
1827 * halts).
1828 */
1829unsigned int audit_serial(void)
1830{
1831 static atomic_t serial = ATOMIC_INIT(0);
1832
1833 return atomic_inc_return(&serial);
1834}
1835
1836static inline void audit_get_stamp(struct audit_context *ctx,
1837 struct timespec64 *t, unsigned int *serial)
1838{
1839 if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
1840 ktime_get_coarse_real_ts64(t);
1841 *serial = audit_serial();
1842 }
1843}
1844
1845/**
1846 * audit_log_start - obtain an audit buffer
1847 * @ctx: audit_context (may be NULL)
1848 * @gfp_mask: type of allocation
1849 * @type: audit message type
1850 *
1851 * Returns audit_buffer pointer on success or NULL on error.
1852 *
1853 * Obtain an audit buffer. This routine does locking to obtain the
1854 * audit buffer, but then no locking is required for calls to
1855 * audit_log_*format. If the task (ctx) is a task that is currently in a
1856 * syscall, then the syscall is marked as auditable and an audit record
1857 * will be written at syscall exit. If there is no associated task, then
1858 * task context (ctx) should be NULL.
1859 */
1860struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1861 int type)
1862{
1863 struct audit_buffer *ab;
1864 struct timespec64 t;
1865 unsigned int serial;
1866
1867 if (audit_initialized != AUDIT_INITIALIZED)
1868 return NULL;
1869
1870 if (unlikely(!audit_filter(type, AUDIT_FILTER_EXCLUDE)))
1871 return NULL;
1872
1873 /* NOTE: don't ever fail/sleep on these two conditions:
1874 * 1. auditd generated record - since we need auditd to drain the
1875 * queue; also, when we are checking for auditd, compare PIDs using
1876 * task_tgid_vnr() since auditd_pid is set in audit_receive_msg()
1877 * using a PID anchored in the caller's namespace
1878 * 2. generator holding the audit_cmd_mutex - we don't want to block
1879 * while holding the mutex, although we do penalize the sender
1880 * later in audit_receive() when it is safe to block
1881 */
1882 if (!(auditd_test_task(current) || audit_ctl_owner_current())) {
1883 long stime = audit_backlog_wait_time;
1884
1885 while (audit_backlog_limit &&
1886 (skb_queue_len(&audit_queue) > audit_backlog_limit)) {
1887 /* wake kauditd to try and flush the queue */
1888 wake_up_interruptible(&kauditd_wait);
1889
1890 /* sleep if we are allowed and we haven't exhausted our
1891 * backlog wait limit */
1892 if (gfpflags_allow_blocking(gfp_mask) && (stime > 0)) {
1893 long rtime = stime;
1894
1895 DECLARE_WAITQUEUE(wait, current);
1896
1897 add_wait_queue_exclusive(&audit_backlog_wait,
1898 &wait);
1899 set_current_state(TASK_UNINTERRUPTIBLE);
1900 stime = schedule_timeout(rtime);
1901 atomic_add(rtime - stime, &audit_backlog_wait_time_actual);
1902 remove_wait_queue(&audit_backlog_wait, &wait);
1903 } else {
1904 if (audit_rate_check() && printk_ratelimit())
1905 pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
1906 skb_queue_len(&audit_queue),
1907 audit_backlog_limit);
1908 audit_log_lost("backlog limit exceeded");
1909 return NULL;
1910 }
1911 }
1912 }
1913
1914 ab = audit_buffer_alloc(ctx, gfp_mask, type);
1915 if (!ab) {
1916 audit_log_lost("out of memory in audit_log_start");
1917 return NULL;
1918 }
1919
1920 audit_get_stamp(ab->ctx, &t, &serial);
1921 /* cancel dummy context to enable supporting records */
1922 if (ctx)
1923 ctx->dummy = 0;
1924 audit_log_format(ab, "audit(%llu.%03lu:%u): ",
1925 (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
1926
1927 return ab;
1928}
1929
1930/**
1931 * audit_expand - expand skb in the audit buffer
1932 * @ab: audit_buffer
1933 * @extra: space to add at tail of the skb
1934 *
1935 * Returns 0 (no space) on failed expansion, or available space if
1936 * successful.
1937 */
1938static inline int audit_expand(struct audit_buffer *ab, int extra)
1939{
1940 struct sk_buff *skb = ab->skb;
1941 int oldtail = skb_tailroom(skb);
1942 int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1943 int newtail = skb_tailroom(skb);
1944
1945 if (ret < 0) {
1946 audit_log_lost("out of memory in audit_expand");
1947 return 0;
1948 }
1949
1950 skb->truesize += newtail - oldtail;
1951 return newtail;
1952}
1953
1954/*
1955 * Format an audit message into the audit buffer. If there isn't enough
1956 * room in the audit buffer, more room will be allocated and vsnprint
1957 * will be called a second time. Currently, we assume that a printk
1958 * can't format message larger than 1024 bytes, so we don't either.
1959 */
1960static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1961 va_list args)
1962{
1963 int len, avail;
1964 struct sk_buff *skb;
1965 va_list args2;
1966
1967 if (!ab)
1968 return;
1969
1970 BUG_ON(!ab->skb);
1971 skb = ab->skb;
1972 avail = skb_tailroom(skb);
1973 if (avail == 0) {
1974 avail = audit_expand(ab, AUDIT_BUFSIZ);
1975 if (!avail)
1976 goto out;
1977 }
1978 va_copy(args2, args);
1979 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1980 if (len >= avail) {
1981 /* The printk buffer is 1024 bytes long, so if we get
1982 * here and AUDIT_BUFSIZ is at least 1024, then we can
1983 * log everything that printk could have logged. */
1984 avail = audit_expand(ab,
1985 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1986 if (!avail)
1987 goto out_va_end;
1988 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1989 }
1990 if (len > 0)
1991 skb_put(skb, len);
1992out_va_end:
1993 va_end(args2);
1994out:
1995 return;
1996}
1997
1998/**
1999 * audit_log_format - format a message into the audit buffer.
2000 * @ab: audit_buffer
2001 * @fmt: format string
2002 * @...: optional parameters matching @fmt string
2003 *
2004 * All the work is done in audit_log_vformat.
2005 */
2006void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
2007{
2008 va_list args;
2009
2010 if (!ab)
2011 return;
2012 va_start(args, fmt);
2013 audit_log_vformat(ab, fmt, args);
2014 va_end(args);
2015}
2016
2017/**
2018 * audit_log_n_hex - convert a buffer to hex and append it to the audit skb
2019 * @ab: the audit_buffer
2020 * @buf: buffer to convert to hex
2021 * @len: length of @buf to be converted
2022 *
2023 * No return value; failure to expand is silently ignored.
2024 *
2025 * This function will take the passed buf and convert it into a string of
2026 * ascii hex digits. The new string is placed onto the skb.
2027 */
2028void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
2029 size_t len)
2030{
2031 int i, avail, new_len;
2032 unsigned char *ptr;
2033 struct sk_buff *skb;
2034
2035 if (!ab)
2036 return;
2037
2038 BUG_ON(!ab->skb);
2039 skb = ab->skb;
2040 avail = skb_tailroom(skb);
2041 new_len = len<<1;
2042 if (new_len >= avail) {
2043 /* Round the buffer request up to the next multiple */
2044 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
2045 avail = audit_expand(ab, new_len);
2046 if (!avail)
2047 return;
2048 }
2049
2050 ptr = skb_tail_pointer(skb);
2051 for (i = 0; i < len; i++)
2052 ptr = hex_byte_pack_upper(ptr, buf[i]);
2053 *ptr = 0;
2054 skb_put(skb, len << 1); /* new string is twice the old string */
2055}
2056
2057/*
2058 * Format a string of no more than slen characters into the audit buffer,
2059 * enclosed in quote marks.
2060 */
2061void audit_log_n_string(struct audit_buffer *ab, const char *string,
2062 size_t slen)
2063{
2064 int avail, new_len;
2065 unsigned char *ptr;
2066 struct sk_buff *skb;
2067
2068 if (!ab)
2069 return;
2070
2071 BUG_ON(!ab->skb);
2072 skb = ab->skb;
2073 avail = skb_tailroom(skb);
2074 new_len = slen + 3; /* enclosing quotes + null terminator */
2075 if (new_len > avail) {
2076 avail = audit_expand(ab, new_len);
2077 if (!avail)
2078 return;
2079 }
2080 ptr = skb_tail_pointer(skb);
2081 *ptr++ = '"';
2082 memcpy(ptr, string, slen);
2083 ptr += slen;
2084 *ptr++ = '"';
2085 *ptr = 0;
2086 skb_put(skb, slen + 2); /* don't include null terminator */
2087}
2088
2089/**
2090 * audit_string_contains_control - does a string need to be logged in hex
2091 * @string: string to be checked
2092 * @len: max length of the string to check
2093 */
2094bool audit_string_contains_control(const char *string, size_t len)
2095{
2096 const unsigned char *p;
2097 for (p = string; p < (const unsigned char *)string + len; p++) {
2098 if (*p == '"' || *p < 0x21 || *p > 0x7e)
2099 return true;
2100 }
2101 return false;
2102}
2103
2104/**
2105 * audit_log_n_untrustedstring - log a string that may contain random characters
2106 * @ab: audit_buffer
2107 * @len: length of string (not including trailing null)
2108 * @string: string to be logged
2109 *
2110 * This code will escape a string that is passed to it if the string
2111 * contains a control character, unprintable character, double quote mark,
2112 * or a space. Unescaped strings will start and end with a double quote mark.
2113 * Strings that are escaped are printed in hex (2 digits per char).
2114 *
2115 * The caller specifies the number of characters in the string to log, which may
2116 * or may not be the entire string.
2117 */
2118void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
2119 size_t len)
2120{
2121 if (audit_string_contains_control(string, len))
2122 audit_log_n_hex(ab, string, len);
2123 else
2124 audit_log_n_string(ab, string, len);
2125}
2126
2127/**
2128 * audit_log_untrustedstring - log a string that may contain random characters
2129 * @ab: audit_buffer
2130 * @string: string to be logged
2131 *
2132 * Same as audit_log_n_untrustedstring(), except that strlen is used to
2133 * determine string length.
2134 */
2135void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
2136{
2137 audit_log_n_untrustedstring(ab, string, strlen(string));
2138}
2139
2140/* This is a helper-function to print the escaped d_path */
2141void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
2142 const struct path *path)
2143{
2144 char *p, *pathname;
2145
2146 if (prefix)
2147 audit_log_format(ab, "%s", prefix);
2148
2149 /* We will allow 11 spaces for ' (deleted)' to be appended */
2150 pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
2151 if (!pathname) {
2152 audit_log_format(ab, "\"<no_memory>\"");
2153 return;
2154 }
2155 p = d_path(path, pathname, PATH_MAX+11);
2156 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
2157 /* FIXME: can we save some information here? */
2158 audit_log_format(ab, "\"<too_long>\"");
2159 } else
2160 audit_log_untrustedstring(ab, p);
2161 kfree(pathname);
2162}
2163
2164void audit_log_session_info(struct audit_buffer *ab)
2165{
2166 unsigned int sessionid = audit_get_sessionid(current);
2167 uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
2168
2169 audit_log_format(ab, "auid=%u ses=%u", auid, sessionid);
2170}
2171
2172void audit_log_key(struct audit_buffer *ab, char *key)
2173{
2174 audit_log_format(ab, " key=");
2175 if (key)
2176 audit_log_untrustedstring(ab, key);
2177 else
2178 audit_log_format(ab, "(null)");
2179}
2180
2181int audit_log_task_context(struct audit_buffer *ab)
2182{
2183 char *ctx = NULL;
2184 unsigned len;
2185 int error;
2186 u32 sid;
2187
2188 security_current_getsecid_subj(&sid);
2189 if (!sid)
2190 return 0;
2191
2192 error = security_secid_to_secctx(sid, &ctx, &len);
2193 if (error) {
2194 if (error != -EINVAL)
2195 goto error_path;
2196 return 0;
2197 }
2198
2199 audit_log_format(ab, " subj=%s", ctx);
2200 security_release_secctx(ctx, len);
2201 return 0;
2202
2203error_path:
2204 audit_panic("error in audit_log_task_context");
2205 return error;
2206}
2207EXPORT_SYMBOL(audit_log_task_context);
2208
2209void audit_log_d_path_exe(struct audit_buffer *ab,
2210 struct mm_struct *mm)
2211{
2212 struct file *exe_file;
2213
2214 if (!mm)
2215 goto out_null;
2216
2217 exe_file = get_mm_exe_file(mm);
2218 if (!exe_file)
2219 goto out_null;
2220
2221 audit_log_d_path(ab, " exe=", &exe_file->f_path);
2222 fput(exe_file);
2223 return;
2224out_null:
2225 audit_log_format(ab, " exe=(null)");
2226}
2227
2228struct tty_struct *audit_get_tty(void)
2229{
2230 struct tty_struct *tty = NULL;
2231 unsigned long flags;
2232
2233 spin_lock_irqsave(¤t->sighand->siglock, flags);
2234 if (current->signal)
2235 tty = tty_kref_get(current->signal->tty);
2236 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
2237 return tty;
2238}
2239
2240void audit_put_tty(struct tty_struct *tty)
2241{
2242 tty_kref_put(tty);
2243}
2244
2245void audit_log_task_info(struct audit_buffer *ab)
2246{
2247 const struct cred *cred;
2248 char comm[sizeof(current->comm)];
2249 struct tty_struct *tty;
2250
2251 if (!ab)
2252 return;
2253
2254 cred = current_cred();
2255 tty = audit_get_tty();
2256 audit_log_format(ab,
2257 " ppid=%d pid=%d auid=%u uid=%u gid=%u"
2258 " euid=%u suid=%u fsuid=%u"
2259 " egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
2260 task_ppid_nr(current),
2261 task_tgid_nr(current),
2262 from_kuid(&init_user_ns, audit_get_loginuid(current)),
2263 from_kuid(&init_user_ns, cred->uid),
2264 from_kgid(&init_user_ns, cred->gid),
2265 from_kuid(&init_user_ns, cred->euid),
2266 from_kuid(&init_user_ns, cred->suid),
2267 from_kuid(&init_user_ns, cred->fsuid),
2268 from_kgid(&init_user_ns, cred->egid),
2269 from_kgid(&init_user_ns, cred->sgid),
2270 from_kgid(&init_user_ns, cred->fsgid),
2271 tty ? tty_name(tty) : "(none)",
2272 audit_get_sessionid(current));
2273 audit_put_tty(tty);
2274 audit_log_format(ab, " comm=");
2275 audit_log_untrustedstring(ab, get_task_comm(comm, current));
2276 audit_log_d_path_exe(ab, current->mm);
2277 audit_log_task_context(ab);
2278}
2279EXPORT_SYMBOL(audit_log_task_info);
2280
2281/**
2282 * audit_log_path_denied - report a path restriction denial
2283 * @type: audit message type (AUDIT_ANOM_LINK, AUDIT_ANOM_CREAT, etc)
2284 * @operation: specific operation name
2285 */
2286void audit_log_path_denied(int type, const char *operation)
2287{
2288 struct audit_buffer *ab;
2289
2290 if (!audit_enabled || audit_dummy_context())
2291 return;
2292
2293 /* Generate log with subject, operation, outcome. */
2294 ab = audit_log_start(audit_context(), GFP_KERNEL, type);
2295 if (!ab)
2296 return;
2297 audit_log_format(ab, "op=%s", operation);
2298 audit_log_task_info(ab);
2299 audit_log_format(ab, " res=0");
2300 audit_log_end(ab);
2301}
2302
2303/* global counter which is incremented every time something logs in */
2304static atomic_t session_id = ATOMIC_INIT(0);
2305
2306static int audit_set_loginuid_perm(kuid_t loginuid)
2307{
2308 /* if we are unset, we don't need privs */
2309 if (!audit_loginuid_set(current))
2310 return 0;
2311 /* if AUDIT_FEATURE_LOGINUID_IMMUTABLE means never ever allow a change*/
2312 if (is_audit_feature_set(AUDIT_FEATURE_LOGINUID_IMMUTABLE))
2313 return -EPERM;
2314 /* it is set, you need permission */
2315 if (!capable(CAP_AUDIT_CONTROL))
2316 return -EPERM;
2317 /* reject if this is not an unset and we don't allow that */
2318 if (is_audit_feature_set(AUDIT_FEATURE_ONLY_UNSET_LOGINUID)
2319 && uid_valid(loginuid))
2320 return -EPERM;
2321 return 0;
2322}
2323
2324static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
2325 unsigned int oldsessionid,
2326 unsigned int sessionid, int rc)
2327{
2328 struct audit_buffer *ab;
2329 uid_t uid, oldloginuid, loginuid;
2330 struct tty_struct *tty;
2331
2332 if (!audit_enabled)
2333 return;
2334
2335 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_LOGIN);
2336 if (!ab)
2337 return;
2338
2339 uid = from_kuid(&init_user_ns, task_uid(current));
2340 oldloginuid = from_kuid(&init_user_ns, koldloginuid);
2341 loginuid = from_kuid(&init_user_ns, kloginuid);
2342 tty = audit_get_tty();
2343
2344 audit_log_format(ab, "pid=%d uid=%u", task_tgid_nr(current), uid);
2345 audit_log_task_context(ab);
2346 audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",
2347 oldloginuid, loginuid, tty ? tty_name(tty) : "(none)",
2348 oldsessionid, sessionid, !rc);
2349 audit_put_tty(tty);
2350 audit_log_end(ab);
2351}
2352
2353/**
2354 * audit_set_loginuid - set current task's loginuid
2355 * @loginuid: loginuid value
2356 *
2357 * Returns 0.
2358 *
2359 * Called (set) from fs/proc/base.c::proc_loginuid_write().
2360 */
2361int audit_set_loginuid(kuid_t loginuid)
2362{
2363 unsigned int oldsessionid, sessionid = AUDIT_SID_UNSET;
2364 kuid_t oldloginuid;
2365 int rc;
2366
2367 oldloginuid = audit_get_loginuid(current);
2368 oldsessionid = audit_get_sessionid(current);
2369
2370 rc = audit_set_loginuid_perm(loginuid);
2371 if (rc)
2372 goto out;
2373
2374 /* are we setting or clearing? */
2375 if (uid_valid(loginuid)) {
2376 sessionid = (unsigned int)atomic_inc_return(&session_id);
2377 if (unlikely(sessionid == AUDIT_SID_UNSET))
2378 sessionid = (unsigned int)atomic_inc_return(&session_id);
2379 }
2380
2381 current->sessionid = sessionid;
2382 current->loginuid = loginuid;
2383out:
2384 audit_log_set_loginuid(oldloginuid, loginuid, oldsessionid, sessionid, rc);
2385 return rc;
2386}
2387
2388/**
2389 * audit_signal_info - record signal info for shutting down audit subsystem
2390 * @sig: signal value
2391 * @t: task being signaled
2392 *
2393 * If the audit subsystem is being terminated, record the task (pid)
2394 * and uid that is doing that.
2395 */
2396int audit_signal_info(int sig, struct task_struct *t)
2397{
2398 kuid_t uid = current_uid(), auid;
2399
2400 if (auditd_test_task(t) &&
2401 (sig == SIGTERM || sig == SIGHUP ||
2402 sig == SIGUSR1 || sig == SIGUSR2)) {
2403 audit_sig_pid = task_tgid_nr(current);
2404 auid = audit_get_loginuid(current);
2405 if (uid_valid(auid))
2406 audit_sig_uid = auid;
2407 else
2408 audit_sig_uid = uid;
2409 security_current_getsecid_subj(&audit_sig_sid);
2410 }
2411
2412 return audit_signal_info_syscall(t);
2413}
2414
2415/**
2416 * audit_log_end - end one audit record
2417 * @ab: the audit_buffer
2418 *
2419 * We can not do a netlink send inside an irq context because it blocks (last
2420 * arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a
2421 * queue and a kthread is scheduled to remove them from the queue outside the
2422 * irq context. May be called in any context.
2423 */
2424void audit_log_end(struct audit_buffer *ab)
2425{
2426 struct sk_buff *skb;
2427 struct nlmsghdr *nlh;
2428
2429 if (!ab)
2430 return;
2431
2432 if (audit_rate_check()) {
2433 skb = ab->skb;
2434 ab->skb = NULL;
2435
2436 /* setup the netlink header, see the comments in
2437 * kauditd_send_multicast_skb() for length quirks */
2438 nlh = nlmsg_hdr(skb);
2439 nlh->nlmsg_len = skb->len - NLMSG_HDRLEN;
2440
2441 /* queue the netlink packet and poke the kauditd thread */
2442 skb_queue_tail(&audit_queue, skb);
2443 wake_up_interruptible(&kauditd_wait);
2444 } else
2445 audit_log_lost("rate limit exceeded");
2446
2447 audit_buffer_free(ab);
2448}
2449
2450/**
2451 * audit_log - Log an audit record
2452 * @ctx: audit context
2453 * @gfp_mask: type of allocation
2454 * @type: audit message type
2455 * @fmt: format string to use
2456 * @...: variable parameters matching the format string
2457 *
2458 * This is a convenience function that calls audit_log_start,
2459 * audit_log_vformat, and audit_log_end. It may be called
2460 * in any context.
2461 */
2462void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
2463 const char *fmt, ...)
2464{
2465 struct audit_buffer *ab;
2466 va_list args;
2467
2468 ab = audit_log_start(ctx, gfp_mask, type);
2469 if (ab) {
2470 va_start(args, fmt);
2471 audit_log_vformat(ab, fmt, args);
2472 va_end(args);
2473 audit_log_end(ab);
2474 }
2475}
2476
2477EXPORT_SYMBOL(audit_log_start);
2478EXPORT_SYMBOL(audit_log_end);
2479EXPORT_SYMBOL(audit_log_format);
2480EXPORT_SYMBOL(audit_log);