projects/linux·blob v4.5 · refs

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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 <[email protected]>
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/file.h>
47#include <linux/init.h>
48#include <linux/types.h>
49#include <linux/atomic.h>
50#include <linux/mm.h>
51#include <linux/export.h>
52#include <linux/slab.h>
53#include <linux/err.h>
54#include <linux/kthread.h>
55#include <linux/kernel.h>
56#include <linux/syscalls.h>
57
58#include <linux/audit.h>
59
60#include <net/sock.h>
61#include <net/netlink.h>
62#include <linux/skbuff.h>
63#ifdef CONFIG_SECURITY
64#include <linux/security.h>
65#endif
66#include <linux/freezer.h>
67#include <linux/tty.h>
68#include <linux/pid_namespace.h>
69#include <net/netns/generic.h>
70
71#include "audit.h"
72
73/* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
74 * (Initialization happens after skb_init is called.) */
75#define AUDIT_DISABLED -1
76#define AUDIT_UNINITIALIZED 0
77#define AUDIT_INITIALIZED 1
78static int audit_initialized;
79
80#define AUDIT_OFF 0
81#define AUDIT_ON 1
82#define AUDIT_LOCKED 2
83u32 audit_enabled;
84u32 audit_ever_enabled;
85
86EXPORT_SYMBOL_GPL(audit_enabled);
87
88/* Default state when kernel boots without any parameters. */
89static u32 audit_default;
90
91/* If auditing cannot proceed, audit_failure selects what happens. */
92static u32 audit_failure = AUDIT_FAIL_PRINTK;
93
94/*
95 * If audit records are to be written to the netlink socket, audit_pid
96 * contains the pid of the auditd process and audit_nlk_portid contains
97 * the portid to use to send netlink messages to that process.
98 */
99int audit_pid;
100static __u32 audit_nlk_portid;
101
102/* If audit_rate_limit is non-zero, limit the rate of sending audit records
103 * to that number per second. This prevents DoS attacks, but results in
104 * audit records being dropped. */
105static u32 audit_rate_limit;
106
107/* Number of outstanding audit_buffers allowed.
108 * When set to zero, this means unlimited. */
109static u32 audit_backlog_limit = 64;
110#define AUDIT_BACKLOG_WAIT_TIME (60 * HZ)
111static u32 audit_backlog_wait_time_master = AUDIT_BACKLOG_WAIT_TIME;
112static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
113
114/* The identity of the user shutting down the audit system. */
115kuid_t audit_sig_uid = INVALID_UID;
116pid_t audit_sig_pid = -1;
117u32 audit_sig_sid = 0;
118
119/* Records can be lost in several ways:
120 0) [suppressed in audit_alloc]
121 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
122 2) out of memory in audit_log_move [alloc_skb]
123 3) suppressed due to audit_rate_limit
124 4) suppressed due to audit_backlog_limit
125*/
126static atomic_t audit_lost = ATOMIC_INIT(0);
127
128/* The netlink socket. */
129static struct sock *audit_sock;
130static int audit_net_id;
131
132/* Hash for inode-based rules */
133struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
134
135/* The audit_freelist is a list of pre-allocated audit buffers (if more
136 * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
137 * being placed on the freelist). */
138static DEFINE_SPINLOCK(audit_freelist_lock);
139static int audit_freelist_count;
140static LIST_HEAD(audit_freelist);
141
142static struct sk_buff_head audit_skb_queue;
143/* queue of skbs to send to auditd when/if it comes back */
144static struct sk_buff_head audit_skb_hold_queue;
145static struct task_struct *kauditd_task;
146static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
147static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
148
149static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION,
150 .mask = -1,
151 .features = 0,
152 .lock = 0,};
153
154static char *audit_feature_names[2] = {
155 "only_unset_loginuid",
156 "loginuid_immutable",
157};
158
159
160/* Serialize requests from userspace. */
161DEFINE_MUTEX(audit_cmd_mutex);
162
163/* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
164 * audit records. Since printk uses a 1024 byte buffer, this buffer
165 * should be at least that large. */
166#define AUDIT_BUFSIZ 1024
167
168/* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the
169 * audit_freelist. Doing so eliminates many kmalloc/kfree calls. */
170#define AUDIT_MAXFREE (2*NR_CPUS)
171
172/* The audit_buffer is used when formatting an audit record. The caller
173 * locks briefly to get the record off the freelist or to allocate the
174 * buffer, and locks briefly to send the buffer to the netlink layer or
175 * to place it on a transmit queue. Multiple audit_buffers can be in
176 * use simultaneously. */
177struct audit_buffer {
178 struct list_head list;
179 struct sk_buff *skb; /* formatted skb ready to send */
180 struct audit_context *ctx; /* NULL or associated context */
181 gfp_t gfp_mask;
182};
183
184struct audit_reply {
185 __u32 portid;
186 struct net *net;
187 struct sk_buff *skb;
188};
189
190static void audit_set_portid(struct audit_buffer *ab, __u32 portid)
191{
192 if (ab) {
193 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
194 nlh->nlmsg_pid = portid;
195 }
196}
197
198void audit_panic(const char *message)
199{
200 switch (audit_failure) {
201 case AUDIT_FAIL_SILENT:
202 break;
203 case AUDIT_FAIL_PRINTK:
204 if (printk_ratelimit())
205 pr_err("%s\n", message);
206 break;
207 case AUDIT_FAIL_PANIC:
208 /* test audit_pid since printk is always losey, why bother? */
209 if (audit_pid)
210 panic("audit: %s\n", message);
211 break;
212 }
213}
214
215static inline int audit_rate_check(void)
216{
217 static unsigned long last_check = 0;
218 static int messages = 0;
219 static DEFINE_SPINLOCK(lock);
220 unsigned long flags;
221 unsigned long now;
222 unsigned long elapsed;
223 int retval = 0;
224
225 if (!audit_rate_limit) return 1;
226
227 spin_lock_irqsave(&lock, flags);
228 if (++messages < audit_rate_limit) {
229 retval = 1;
230 } else {
231 now = jiffies;
232 elapsed = now - last_check;
233 if (elapsed > HZ) {
234 last_check = now;
235 messages = 0;
236 retval = 1;
237 }
238 }
239 spin_unlock_irqrestore(&lock, flags);
240
241 return retval;
242}
243
244/**
245 * audit_log_lost - conditionally log lost audit message event
246 * @message: the message stating reason for lost audit message
247 *
248 * Emit at least 1 message per second, even if audit_rate_check is
249 * throttling.
250 * Always increment the lost messages counter.
251*/
252void audit_log_lost(const char *message)
253{
254 static unsigned long last_msg = 0;
255 static DEFINE_SPINLOCK(lock);
256 unsigned long flags;
257 unsigned long now;
258 int print;
259
260 atomic_inc(&audit_lost);
261
262 print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
263
264 if (!print) {
265 spin_lock_irqsave(&lock, flags);
266 now = jiffies;
267 if (now - last_msg > HZ) {
268 print = 1;
269 last_msg = now;
270 }
271 spin_unlock_irqrestore(&lock, flags);
272 }
273
274 if (print) {
275 if (printk_ratelimit())
276 pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
277 atomic_read(&audit_lost),
278 audit_rate_limit,
279 audit_backlog_limit);
280 audit_panic(message);
281 }
282}
283
284static int audit_log_config_change(char *function_name, u32 new, u32 old,
285 int allow_changes)
286{
287 struct audit_buffer *ab;
288 int rc = 0;
289
290 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
291 if (unlikely(!ab))
292 return rc;
293 audit_log_format(ab, "%s=%u old=%u", function_name, new, old);
294 audit_log_session_info(ab);
295 rc = audit_log_task_context(ab);
296 if (rc)
297 allow_changes = 0; /* Something weird, deny request */
298 audit_log_format(ab, " res=%d", allow_changes);
299 audit_log_end(ab);
300 return rc;
301}
302
303static int audit_do_config_change(char *function_name, u32 *to_change, u32 new)
304{
305 int allow_changes, rc = 0;
306 u32 old = *to_change;
307
308 /* check if we are locked */
309 if (audit_enabled == AUDIT_LOCKED)
310 allow_changes = 0;
311 else
312 allow_changes = 1;
313
314 if (audit_enabled != AUDIT_OFF) {
315 rc = audit_log_config_change(function_name, new, old, allow_changes);
316 if (rc)
317 allow_changes = 0;
318 }
319
320 /* If we are allowed, make the change */
321 if (allow_changes == 1)
322 *to_change = new;
323 /* Not allowed, update reason */
324 else if (rc == 0)
325 rc = -EPERM;
326 return rc;
327}
328
329static int audit_set_rate_limit(u32 limit)
330{
331 return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit);
332}
333
334static int audit_set_backlog_limit(u32 limit)
335{
336 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit);
337}
338
339static int audit_set_backlog_wait_time(u32 timeout)
340{
341 return audit_do_config_change("audit_backlog_wait_time",
342 &audit_backlog_wait_time_master, timeout);
343}
344
345static int audit_set_enabled(u32 state)
346{
347 int rc;
348 if (state > AUDIT_LOCKED)
349 return -EINVAL;
350
351 rc = audit_do_config_change("audit_enabled", &audit_enabled, state);
352 if (!rc)
353 audit_ever_enabled |= !!state;
354
355 return rc;
356}
357
358static int audit_set_failure(u32 state)
359{
360 if (state != AUDIT_FAIL_SILENT
361 && state != AUDIT_FAIL_PRINTK
362 && state != AUDIT_FAIL_PANIC)
363 return -EINVAL;
364
365 return audit_do_config_change("audit_failure", &audit_failure, state);
366}
367
368/*
369 * Queue skbs to be sent to auditd when/if it comes back. These skbs should
370 * already have been sent via prink/syslog and so if these messages are dropped
371 * it is not a huge concern since we already passed the audit_log_lost()
372 * notification and stuff. This is just nice to get audit messages during
373 * boot before auditd is running or messages generated while auditd is stopped.
374 * This only holds messages is audit_default is set, aka booting with audit=1
375 * or building your kernel that way.
376 */
377static void audit_hold_skb(struct sk_buff *skb)
378{
379 if (audit_default &&
380 (!audit_backlog_limit ||
381 skb_queue_len(&audit_skb_hold_queue) < audit_backlog_limit))
382 skb_queue_tail(&audit_skb_hold_queue, skb);
383 else
384 kfree_skb(skb);
385}
386
387/*
388 * For one reason or another this nlh isn't getting delivered to the userspace
389 * audit daemon, just send it to printk.
390 */
391static void audit_printk_skb(struct sk_buff *skb)
392{
393 struct nlmsghdr *nlh = nlmsg_hdr(skb);
394 char *data = nlmsg_data(nlh);
395
396 if (nlh->nlmsg_type != AUDIT_EOE) {
397 if (printk_ratelimit())
398 pr_notice("type=%d %s\n", nlh->nlmsg_type, data);
399 else
400 audit_log_lost("printk limit exceeded");
401 }
402
403 audit_hold_skb(skb);
404}
405
406static void kauditd_send_skb(struct sk_buff *skb)
407{
408 int err;
409 int attempts = 0;
410#define AUDITD_RETRIES 5
411
412restart:
413 /* take a reference in case we can't send it and we want to hold it */
414 skb_get(skb);
415 err = netlink_unicast(audit_sock, skb, audit_nlk_portid, 0);
416 if (err < 0) {
417 pr_err("netlink_unicast sending to audit_pid=%d returned error: %d\n",
418 audit_pid, err);
419 if (audit_pid) {
420 if (err == -ECONNREFUSED || err == -EPERM
421 || ++attempts >= AUDITD_RETRIES) {
422 char s[32];
423
424 snprintf(s, sizeof(s), "audit_pid=%d reset", audit_pid);
425 audit_log_lost(s);
426 audit_pid = 0;
427 audit_sock = NULL;
428 } else {
429 pr_warn("re-scheduling(#%d) write to audit_pid=%d\n",
430 attempts, audit_pid);
431 set_current_state(TASK_INTERRUPTIBLE);
432 schedule();
433 __set_current_state(TASK_RUNNING);
434 goto restart;
435 }
436 }
437 /* we might get lucky and get this in the next auditd */
438 audit_hold_skb(skb);
439 } else
440 /* drop the extra reference if sent ok */
441 consume_skb(skb);
442}
443
444/*
445 * kauditd_send_multicast_skb - send the skb to multicast userspace listeners
446 *
447 * This function doesn't consume an skb as might be expected since it has to
448 * copy it anyways.
449 */
450static void kauditd_send_multicast_skb(struct sk_buff *skb, gfp_t gfp_mask)
451{
452 struct sk_buff *copy;
453 struct audit_net *aunet = net_generic(&init_net, audit_net_id);
454 struct sock *sock = aunet->nlsk;
455
456 if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
457 return;
458
459 /*
460 * The seemingly wasteful skb_copy() rather than bumping the refcount
461 * using skb_get() is necessary because non-standard mods are made to
462 * the skb by the original kaudit unicast socket send routine. The
463 * existing auditd daemon assumes this breakage. Fixing this would
464 * require co-ordinating a change in the established protocol between
465 * the kaudit kernel subsystem and the auditd userspace code. There is
466 * no reason for new multicast clients to continue with this
467 * non-compliance.
468 */
469 copy = skb_copy(skb, gfp_mask);
470 if (!copy)
471 return;
472
473 nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, gfp_mask);
474}
475
476/*
477 * flush_hold_queue - empty the hold queue if auditd appears
478 *
479 * If auditd just started, drain the queue of messages already
480 * sent to syslog/printk. Remember loss here is ok. We already
481 * called audit_log_lost() if it didn't go out normally. so the
482 * race between the skb_dequeue and the next check for audit_pid
483 * doesn't matter.
484 *
485 * If you ever find kauditd to be too slow we can get a perf win
486 * by doing our own locking and keeping better track if there
487 * are messages in this queue. I don't see the need now, but
488 * in 5 years when I want to play with this again I'll see this
489 * note and still have no friggin idea what i'm thinking today.
490 */
491static void flush_hold_queue(void)
492{
493 struct sk_buff *skb;
494
495 if (!audit_default || !audit_pid)
496 return;
497
498 skb = skb_dequeue(&audit_skb_hold_queue);
499 if (likely(!skb))
500 return;
501
502 while (skb && audit_pid) {
503 kauditd_send_skb(skb);
504 skb = skb_dequeue(&audit_skb_hold_queue);
505 }
506
507 /*
508 * if auditd just disappeared but we
509 * dequeued an skb we need to drop ref
510 */
511 consume_skb(skb);
512}
513
514static int kauditd_thread(void *dummy)
515{
516 set_freezable();
517 while (!kthread_should_stop()) {
518 struct sk_buff *skb;
519
520 flush_hold_queue();
521
522 skb = skb_dequeue(&audit_skb_queue);
523
524 if (skb) {
525 if (!audit_backlog_limit ||
526 (skb_queue_len(&audit_skb_queue) <= audit_backlog_limit))
527 wake_up(&audit_backlog_wait);
528 if (audit_pid)
529 kauditd_send_skb(skb);
530 else
531 audit_printk_skb(skb);
532 continue;
533 }
534
535 wait_event_freezable(kauditd_wait, skb_queue_len(&audit_skb_queue));
536 }
537 return 0;
538}
539
540int audit_send_list(void *_dest)
541{
542 struct audit_netlink_list *dest = _dest;
543 struct sk_buff *skb;
544 struct net *net = dest->net;
545 struct audit_net *aunet = net_generic(net, audit_net_id);
546
547 /* wait for parent to finish and send an ACK */
548 mutex_lock(&audit_cmd_mutex);
549 mutex_unlock(&audit_cmd_mutex);
550
551 while ((skb = __skb_dequeue(&dest->q)) != NULL)
552 netlink_unicast(aunet->nlsk, skb, dest->portid, 0);
553
554 put_net(net);
555 kfree(dest);
556
557 return 0;
558}
559
560struct sk_buff *audit_make_reply(__u32 portid, int seq, int type, int done,
561 int multi, const void *payload, int size)
562{
563 struct sk_buff *skb;
564 struct nlmsghdr *nlh;
565 void *data;
566 int flags = multi ? NLM_F_MULTI : 0;
567 int t = done ? NLMSG_DONE : type;
568
569 skb = nlmsg_new(size, GFP_KERNEL);
570 if (!skb)
571 return NULL;
572
573 nlh = nlmsg_put(skb, portid, seq, t, size, flags);
574 if (!nlh)
575 goto out_kfree_skb;
576 data = nlmsg_data(nlh);
577 memcpy(data, payload, size);
578 return skb;
579
580out_kfree_skb:
581 kfree_skb(skb);
582 return NULL;
583}
584
585static int audit_send_reply_thread(void *arg)
586{
587 struct audit_reply *reply = (struct audit_reply *)arg;
588 struct net *net = reply->net;
589 struct audit_net *aunet = net_generic(net, audit_net_id);
590
591 mutex_lock(&audit_cmd_mutex);
592 mutex_unlock(&audit_cmd_mutex);
593
594 /* Ignore failure. It'll only happen if the sender goes away,
595 because our timeout is set to infinite. */
596 netlink_unicast(aunet->nlsk , reply->skb, reply->portid, 0);
597 put_net(net);
598 kfree(reply);
599 return 0;
600}
601/**
602 * audit_send_reply - send an audit reply message via netlink
603 * @request_skb: skb of request we are replying to (used to target the reply)
604 * @seq: sequence number
605 * @type: audit message type
606 * @done: done (last) flag
607 * @multi: multi-part message flag
608 * @payload: payload data
609 * @size: payload size
610 *
611 * Allocates an skb, builds the netlink message, and sends it to the port id.
612 * No failure notifications.
613 */
614static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
615 int multi, const void *payload, int size)
616{
617 u32 portid = NETLINK_CB(request_skb).portid;
618 struct net *net = sock_net(NETLINK_CB(request_skb).sk);
619 struct sk_buff *skb;
620 struct task_struct *tsk;
621 struct audit_reply *reply = kmalloc(sizeof(struct audit_reply),
622 GFP_KERNEL);
623
624 if (!reply)
625 return;
626
627 skb = audit_make_reply(portid, seq, type, done, multi, payload, size);
628 if (!skb)
629 goto out;
630
631 reply->net = get_net(net);
632 reply->portid = portid;
633 reply->skb = skb;
634
635 tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
636 if (!IS_ERR(tsk))
637 return;
638 kfree_skb(skb);
639out:
640 kfree(reply);
641}
642
643/*
644 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
645 * control messages.
646 */
647static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
648{
649 int err = 0;
650
651 /* Only support initial user namespace for now. */
652 /*
653 * We return ECONNREFUSED because it tricks userspace into thinking
654 * that audit was not configured into the kernel. Lots of users
655 * configure their PAM stack (because that's what the distro does)
656 * to reject login if unable to send messages to audit. If we return
657 * ECONNREFUSED the PAM stack thinks the kernel does not have audit
658 * configured in and will let login proceed. If we return EPERM
659 * userspace will reject all logins. This should be removed when we
660 * support non init namespaces!!
661 */
662 if (current_user_ns() != &init_user_ns)
663 return -ECONNREFUSED;
664
665 switch (msg_type) {
666 case AUDIT_LIST:
667 case AUDIT_ADD:
668 case AUDIT_DEL:
669 return -EOPNOTSUPP;
670 case AUDIT_GET:
671 case AUDIT_SET:
672 case AUDIT_GET_FEATURE:
673 case AUDIT_SET_FEATURE:
674 case AUDIT_LIST_RULES:
675 case AUDIT_ADD_RULE:
676 case AUDIT_DEL_RULE:
677 case AUDIT_SIGNAL_INFO:
678 case AUDIT_TTY_GET:
679 case AUDIT_TTY_SET:
680 case AUDIT_TRIM:
681 case AUDIT_MAKE_EQUIV:
682 /* Only support auditd and auditctl in initial pid namespace
683 * for now. */
684 if (task_active_pid_ns(current) != &init_pid_ns)
685 return -EPERM;
686
687 if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
688 err = -EPERM;
689 break;
690 case AUDIT_USER:
691 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
692 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
693 if (!netlink_capable(skb, CAP_AUDIT_WRITE))
694 err = -EPERM;
695 break;
696 default: /* bad msg */
697 err = -EINVAL;
698 }
699
700 return err;
701}
702
703static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
704{
705 uid_t uid = from_kuid(&init_user_ns, current_uid());
706 pid_t pid = task_tgid_nr(current);
707
708 if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
709 *ab = NULL;
710 return;
711 }
712
713 *ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
714 if (unlikely(!*ab))
715 return;
716 audit_log_format(*ab, "pid=%d uid=%u", pid, uid);
717 audit_log_session_info(*ab);
718 audit_log_task_context(*ab);
719}
720
721int is_audit_feature_set(int i)
722{
723 return af.features & AUDIT_FEATURE_TO_MASK(i);
724}
725
726
727static int audit_get_feature(struct sk_buff *skb)
728{
729 u32 seq;
730
731 seq = nlmsg_hdr(skb)->nlmsg_seq;
732
733 audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af));
734
735 return 0;
736}
737
738static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
739 u32 old_lock, u32 new_lock, int res)
740{
741 struct audit_buffer *ab;
742
743 if (audit_enabled == AUDIT_OFF)
744 return;
745
746 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_FEATURE_CHANGE);
747 audit_log_task_info(ab, current);
748 audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
749 audit_feature_names[which], !!old_feature, !!new_feature,
750 !!old_lock, !!new_lock, res);
751 audit_log_end(ab);
752}
753
754static int audit_set_feature(struct sk_buff *skb)
755{
756 struct audit_features *uaf;
757 int i;
758
759 BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
760 uaf = nlmsg_data(nlmsg_hdr(skb));
761
762 /* if there is ever a version 2 we should handle that here */
763
764 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
765 u32 feature = AUDIT_FEATURE_TO_MASK(i);
766 u32 old_feature, new_feature, old_lock, new_lock;
767
768 /* if we are not changing this feature, move along */
769 if (!(feature & uaf->mask))
770 continue;
771
772 old_feature = af.features & feature;
773 new_feature = uaf->features & feature;
774 new_lock = (uaf->lock | af.lock) & feature;
775 old_lock = af.lock & feature;
776
777 /* are we changing a locked feature? */
778 if (old_lock && (new_feature != old_feature)) {
779 audit_log_feature_change(i, old_feature, new_feature,
780 old_lock, new_lock, 0);
781 return -EPERM;
782 }
783 }
784 /* nothing invalid, do the changes */
785 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
786 u32 feature = AUDIT_FEATURE_TO_MASK(i);
787 u32 old_feature, new_feature, old_lock, new_lock;
788
789 /* if we are not changing this feature, move along */
790 if (!(feature & uaf->mask))
791 continue;
792
793 old_feature = af.features & feature;
794 new_feature = uaf->features & feature;
795 old_lock = af.lock & feature;
796 new_lock = (uaf->lock | af.lock) & feature;
797
798 if (new_feature != old_feature)
799 audit_log_feature_change(i, old_feature, new_feature,
800 old_lock, new_lock, 1);
801
802 if (new_feature)
803 af.features |= feature;
804 else
805 af.features &= ~feature;
806 af.lock |= new_lock;
807 }
808
809 return 0;
810}
811
812static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
813{
814 u32 seq;
815 void *data;
816 int err;
817 struct audit_buffer *ab;
818 u16 msg_type = nlh->nlmsg_type;
819 struct audit_sig_info *sig_data;
820 char *ctx = NULL;
821 u32 len;
822
823 err = audit_netlink_ok(skb, msg_type);
824 if (err)
825 return err;
826
827 /* As soon as there's any sign of userspace auditd,
828 * start kauditd to talk to it */
829 if (!kauditd_task) {
830 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
831 if (IS_ERR(kauditd_task)) {
832 err = PTR_ERR(kauditd_task);
833 kauditd_task = NULL;
834 return err;
835 }
836 }
837 seq = nlh->nlmsg_seq;
838 data = nlmsg_data(nlh);
839
840 switch (msg_type) {
841 case AUDIT_GET: {
842 struct audit_status s;
843 memset(&s, 0, sizeof(s));
844 s.enabled = audit_enabled;
845 s.failure = audit_failure;
846 s.pid = audit_pid;
847 s.rate_limit = audit_rate_limit;
848 s.backlog_limit = audit_backlog_limit;
849 s.lost = atomic_read(&audit_lost);
850 s.backlog = skb_queue_len(&audit_skb_queue);
851 s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL;
852 s.backlog_wait_time = audit_backlog_wait_time_master;
853 audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
854 break;
855 }
856 case AUDIT_SET: {
857 struct audit_status s;
858 memset(&s, 0, sizeof(s));
859 /* guard against past and future API changes */
860 memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
861 if (s.mask & AUDIT_STATUS_ENABLED) {
862 err = audit_set_enabled(s.enabled);
863 if (err < 0)
864 return err;
865 }
866 if (s.mask & AUDIT_STATUS_FAILURE) {
867 err = audit_set_failure(s.failure);
868 if (err < 0)
869 return err;
870 }
871 if (s.mask & AUDIT_STATUS_PID) {
872 int new_pid = s.pid;
873
874 if ((!new_pid) && (task_tgid_vnr(current) != audit_pid))
875 return -EACCES;
876 if (audit_enabled != AUDIT_OFF)
877 audit_log_config_change("audit_pid", new_pid, audit_pid, 1);
878 audit_pid = new_pid;
879 audit_nlk_portid = NETLINK_CB(skb).portid;
880 audit_sock = skb->sk;
881 }
882 if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
883 err = audit_set_rate_limit(s.rate_limit);
884 if (err < 0)
885 return err;
886 }
887 if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
888 err = audit_set_backlog_limit(s.backlog_limit);
889 if (err < 0)
890 return err;
891 }
892 if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
893 if (sizeof(s) > (size_t)nlh->nlmsg_len)
894 return -EINVAL;
895 if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
896 return -EINVAL;
897 err = audit_set_backlog_wait_time(s.backlog_wait_time);
898 if (err < 0)
899 return err;
900 }
901 break;
902 }
903 case AUDIT_GET_FEATURE:
904 err = audit_get_feature(skb);
905 if (err)
906 return err;
907 break;
908 case AUDIT_SET_FEATURE:
909 err = audit_set_feature(skb);
910 if (err)
911 return err;
912 break;
913 case AUDIT_USER:
914 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
915 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
916 if (!audit_enabled && msg_type != AUDIT_USER_AVC)
917 return 0;
918
919 err = audit_filter_user(msg_type);
920 if (err == 1) { /* match or error */
921 err = 0;
922 if (msg_type == AUDIT_USER_TTY) {
923 err = tty_audit_push_current();
924 if (err)
925 break;
926 }
927 mutex_unlock(&audit_cmd_mutex);
928 audit_log_common_recv_msg(&ab, msg_type);
929 if (msg_type != AUDIT_USER_TTY)
930 audit_log_format(ab, " msg='%.*s'",
931 AUDIT_MESSAGE_TEXT_MAX,
932 (char *)data);
933 else {
934 int size;
935
936 audit_log_format(ab, " data=");
937 size = nlmsg_len(nlh);
938 if (size > 0 &&
939 ((unsigned char *)data)[size - 1] == '\0')
940 size--;
941 audit_log_n_untrustedstring(ab, data, size);
942 }
943 audit_set_portid(ab, NETLINK_CB(skb).portid);
944 audit_log_end(ab);
945 mutex_lock(&audit_cmd_mutex);
946 }
947 break;
948 case AUDIT_ADD_RULE:
949 case AUDIT_DEL_RULE:
950 if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
951 return -EINVAL;
952 if (audit_enabled == AUDIT_LOCKED) {
953 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
954 audit_log_format(ab, " audit_enabled=%d res=0", audit_enabled);
955 audit_log_end(ab);
956 return -EPERM;
957 }
958 err = audit_rule_change(msg_type, NETLINK_CB(skb).portid,
959 seq, data, nlmsg_len(nlh));
960 break;
961 case AUDIT_LIST_RULES:
962 err = audit_list_rules_send(skb, seq);
963 break;
964 case AUDIT_TRIM:
965 audit_trim_trees();
966 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
967 audit_log_format(ab, " op=trim res=1");
968 audit_log_end(ab);
969 break;
970 case AUDIT_MAKE_EQUIV: {
971 void *bufp = data;
972 u32 sizes[2];
973 size_t msglen = nlmsg_len(nlh);
974 char *old, *new;
975
976 err = -EINVAL;
977 if (msglen < 2 * sizeof(u32))
978 break;
979 memcpy(sizes, bufp, 2 * sizeof(u32));
980 bufp += 2 * sizeof(u32);
981 msglen -= 2 * sizeof(u32);
982 old = audit_unpack_string(&bufp, &msglen, sizes[0]);
983 if (IS_ERR(old)) {
984 err = PTR_ERR(old);
985 break;
986 }
987 new = audit_unpack_string(&bufp, &msglen, sizes[1]);
988 if (IS_ERR(new)) {
989 err = PTR_ERR(new);
990 kfree(old);
991 break;
992 }
993 /* OK, here comes... */
994 err = audit_tag_tree(old, new);
995
996 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
997
998 audit_log_format(ab, " op=make_equiv old=");
999 audit_log_untrustedstring(ab, old);
1000 audit_log_format(ab, " new=");
1001 audit_log_untrustedstring(ab, new);
1002 audit_log_format(ab, " res=%d", !err);
1003 audit_log_end(ab);
1004 kfree(old);
1005 kfree(new);
1006 break;
1007 }
1008 case AUDIT_SIGNAL_INFO:
1009 len = 0;
1010 if (audit_sig_sid) {
1011 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
1012 if (err)
1013 return err;
1014 }
1015 sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
1016 if (!sig_data) {
1017 if (audit_sig_sid)
1018 security_release_secctx(ctx, len);
1019 return -ENOMEM;
1020 }
1021 sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
1022 sig_data->pid = audit_sig_pid;
1023 if (audit_sig_sid) {
1024 memcpy(sig_data->ctx, ctx, len);
1025 security_release_secctx(ctx, len);
1026 }
1027 audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
1028 sig_data, sizeof(*sig_data) + len);
1029 kfree(sig_data);
1030 break;
1031 case AUDIT_TTY_GET: {
1032 struct audit_tty_status s;
1033 struct task_struct *tsk = current;
1034
1035 spin_lock(&tsk->sighand->siglock);
1036 s.enabled = tsk->signal->audit_tty;
1037 s.log_passwd = tsk->signal->audit_tty_log_passwd;
1038 spin_unlock(&tsk->sighand->siglock);
1039
1040 audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
1041 break;
1042 }
1043 case AUDIT_TTY_SET: {
1044 struct audit_tty_status s, old;
1045 struct task_struct *tsk = current;
1046 struct audit_buffer *ab;
1047
1048 memset(&s, 0, sizeof(s));
1049 /* guard against past and future API changes */
1050 memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
1051 /* check if new data is valid */
1052 if ((s.enabled != 0 && s.enabled != 1) ||
1053 (s.log_passwd != 0 && s.log_passwd != 1))
1054 err = -EINVAL;
1055
1056 spin_lock(&tsk->sighand->siglock);
1057 old.enabled = tsk->signal->audit_tty;
1058 old.log_passwd = tsk->signal->audit_tty_log_passwd;
1059 if (!err) {
1060 tsk->signal->audit_tty = s.enabled;
1061 tsk->signal->audit_tty_log_passwd = s.log_passwd;
1062 }
1063 spin_unlock(&tsk->sighand->siglock);
1064
1065 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
1066 audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
1067 " old-log_passwd=%d new-log_passwd=%d res=%d",
1068 old.enabled, s.enabled, old.log_passwd,
1069 s.log_passwd, !err);
1070 audit_log_end(ab);
1071 break;
1072 }
1073 default:
1074 err = -EINVAL;
1075 break;
1076 }
1077
1078 return err < 0 ? err : 0;
1079}
1080
1081/*
1082 * Get message from skb. Each message is processed by audit_receive_msg.
1083 * Malformed skbs with wrong length are discarded silently.
1084 */
1085static void audit_receive_skb(struct sk_buff *skb)
1086{
1087 struct nlmsghdr *nlh;
1088 /*
1089 * len MUST be signed for nlmsg_next to be able to dec it below 0
1090 * if the nlmsg_len was not aligned
1091 */
1092 int len;
1093 int err;
1094
1095 nlh = nlmsg_hdr(skb);
1096 len = skb->len;
1097
1098 while (nlmsg_ok(nlh, len)) {
1099 err = audit_receive_msg(skb, nlh);
1100 /* if err or if this message says it wants a response */
1101 if (err || (nlh->nlmsg_flags & NLM_F_ACK))
1102 netlink_ack(skb, nlh, err);
1103
1104 nlh = nlmsg_next(nlh, &len);
1105 }
1106}
1107
1108/* Receive messages from netlink socket. */
1109static void audit_receive(struct sk_buff *skb)
1110{
1111 mutex_lock(&audit_cmd_mutex);
1112 audit_receive_skb(skb);
1113 mutex_unlock(&audit_cmd_mutex);
1114}
1115
1116/* Run custom bind function on netlink socket group connect or bind requests. */
1117static int audit_bind(struct net *net, int group)
1118{
1119 if (!capable(CAP_AUDIT_READ))
1120 return -EPERM;
1121
1122 return 0;
1123}
1124
1125static int __net_init audit_net_init(struct net *net)
1126{
1127 struct netlink_kernel_cfg cfg = {
1128 .input = audit_receive,
1129 .bind = audit_bind,
1130 .flags = NL_CFG_F_NONROOT_RECV,
1131 .groups = AUDIT_NLGRP_MAX,
1132 };
1133
1134 struct audit_net *aunet = net_generic(net, audit_net_id);
1135
1136 aunet->nlsk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
1137 if (aunet->nlsk == NULL) {
1138 audit_panic("cannot initialize netlink socket in namespace");
1139 return -ENOMEM;
1140 }
1141 aunet->nlsk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
1142 return 0;
1143}
1144
1145static void __net_exit audit_net_exit(struct net *net)
1146{
1147 struct audit_net *aunet = net_generic(net, audit_net_id);
1148 struct sock *sock = aunet->nlsk;
1149 if (sock == audit_sock) {
1150 audit_pid = 0;
1151 audit_sock = NULL;
1152 }
1153
1154 RCU_INIT_POINTER(aunet->nlsk, NULL);
1155 synchronize_net();
1156 netlink_kernel_release(sock);
1157}
1158
1159static struct pernet_operations audit_net_ops __net_initdata = {
1160 .init = audit_net_init,
1161 .exit = audit_net_exit,
1162 .id = &audit_net_id,
1163 .size = sizeof(struct audit_net),
1164};
1165
1166/* Initialize audit support at boot time. */
1167static int __init audit_init(void)
1168{
1169 int i;
1170
1171 if (audit_initialized == AUDIT_DISABLED)
1172 return 0;
1173
1174 pr_info("initializing netlink subsys (%s)\n",
1175 audit_default ? "enabled" : "disabled");
1176 register_pernet_subsys(&audit_net_ops);
1177
1178 skb_queue_head_init(&audit_skb_queue);
1179 skb_queue_head_init(&audit_skb_hold_queue);
1180 audit_initialized = AUDIT_INITIALIZED;
1181 audit_enabled = audit_default;
1182 audit_ever_enabled |= !!audit_default;
1183
1184 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized");
1185
1186 for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
1187 INIT_LIST_HEAD(&audit_inode_hash[i]);
1188
1189 return 0;
1190}
1191__initcall(audit_init);
1192
1193/* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
1194static int __init audit_enable(char *str)
1195{
1196 audit_default = !!simple_strtol(str, NULL, 0);
1197 if (!audit_default)
1198 audit_initialized = AUDIT_DISABLED;
1199
1200 pr_info("%s\n", audit_default ?
1201 "enabled (after initialization)" : "disabled (until reboot)");
1202
1203 return 1;
1204}
1205__setup("audit=", audit_enable);
1206
1207/* Process kernel command-line parameter at boot time.
1208 * audit_backlog_limit=<n> */
1209static int __init audit_backlog_limit_set(char *str)
1210{
1211 u32 audit_backlog_limit_arg;
1212
1213 pr_info("audit_backlog_limit: ");
1214 if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
1215 pr_cont("using default of %u, unable to parse %s\n",
1216 audit_backlog_limit, str);
1217 return 1;
1218 }
1219
1220 audit_backlog_limit = audit_backlog_limit_arg;
1221 pr_cont("%d\n", audit_backlog_limit);
1222
1223 return 1;
1224}
1225__setup("audit_backlog_limit=", audit_backlog_limit_set);
1226
1227static void audit_buffer_free(struct audit_buffer *ab)
1228{
1229 unsigned long flags;
1230
1231 if (!ab)
1232 return;
1233
1234 kfree_skb(ab->skb);
1235 spin_lock_irqsave(&audit_freelist_lock, flags);
1236 if (audit_freelist_count > AUDIT_MAXFREE)
1237 kfree(ab);
1238 else {
1239 audit_freelist_count++;
1240 list_add(&ab->list, &audit_freelist);
1241 }
1242 spin_unlock_irqrestore(&audit_freelist_lock, flags);
1243}
1244
1245static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx,
1246 gfp_t gfp_mask, int type)
1247{
1248 unsigned long flags;
1249 struct audit_buffer *ab = NULL;
1250 struct nlmsghdr *nlh;
1251
1252 spin_lock_irqsave(&audit_freelist_lock, flags);
1253 if (!list_empty(&audit_freelist)) {
1254 ab = list_entry(audit_freelist.next,
1255 struct audit_buffer, list);
1256 list_del(&ab->list);
1257 --audit_freelist_count;
1258 }
1259 spin_unlock_irqrestore(&audit_freelist_lock, flags);
1260
1261 if (!ab) {
1262 ab = kmalloc(sizeof(*ab), gfp_mask);
1263 if (!ab)
1264 goto err;
1265 }
1266
1267 ab->ctx = ctx;
1268 ab->gfp_mask = gfp_mask;
1269
1270 ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
1271 if (!ab->skb)
1272 goto err;
1273
1274 nlh = nlmsg_put(ab->skb, 0, 0, type, 0, 0);
1275 if (!nlh)
1276 goto out_kfree_skb;
1277
1278 return ab;
1279
1280out_kfree_skb:
1281 kfree_skb(ab->skb);
1282 ab->skb = NULL;
1283err:
1284 audit_buffer_free(ab);
1285 return NULL;
1286}
1287
1288/**
1289 * audit_serial - compute a serial number for the audit record
1290 *
1291 * Compute a serial number for the audit record. Audit records are
1292 * written to user-space as soon as they are generated, so a complete
1293 * audit record may be written in several pieces. The timestamp of the
1294 * record and this serial number are used by the user-space tools to
1295 * determine which pieces belong to the same audit record. The
1296 * (timestamp,serial) tuple is unique for each syscall and is live from
1297 * syscall entry to syscall exit.
1298 *
1299 * NOTE: Another possibility is to store the formatted records off the
1300 * audit context (for those records that have a context), and emit them
1301 * all at syscall exit. However, this could delay the reporting of
1302 * significant errors until syscall exit (or never, if the system
1303 * halts).
1304 */
1305unsigned int audit_serial(void)
1306{
1307 static atomic_t serial = ATOMIC_INIT(0);
1308
1309 return atomic_add_return(1, &serial);
1310}
1311
1312static inline void audit_get_stamp(struct audit_context *ctx,
1313 struct timespec *t, unsigned int *serial)
1314{
1315 if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
1316 *t = CURRENT_TIME;
1317 *serial = audit_serial();
1318 }
1319}
1320
1321/*
1322 * Wait for auditd to drain the queue a little
1323 */
1324static long wait_for_auditd(long sleep_time)
1325{
1326 DECLARE_WAITQUEUE(wait, current);
1327 set_current_state(TASK_UNINTERRUPTIBLE);
1328 add_wait_queue_exclusive(&audit_backlog_wait, &wait);
1329
1330 if (audit_backlog_limit &&
1331 skb_queue_len(&audit_skb_queue) > audit_backlog_limit)
1332 sleep_time = schedule_timeout(sleep_time);
1333
1334 __set_current_state(TASK_RUNNING);
1335 remove_wait_queue(&audit_backlog_wait, &wait);
1336
1337 return sleep_time;
1338}
1339
1340/**
1341 * audit_log_start - obtain an audit buffer
1342 * @ctx: audit_context (may be NULL)
1343 * @gfp_mask: type of allocation
1344 * @type: audit message type
1345 *
1346 * Returns audit_buffer pointer on success or NULL on error.
1347 *
1348 * Obtain an audit buffer. This routine does locking to obtain the
1349 * audit buffer, but then no locking is required for calls to
1350 * audit_log_*format. If the task (ctx) is a task that is currently in a
1351 * syscall, then the syscall is marked as auditable and an audit record
1352 * will be written at syscall exit. If there is no associated task, then
1353 * task context (ctx) should be NULL.
1354 */
1355struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1356 int type)
1357{
1358 struct audit_buffer *ab = NULL;
1359 struct timespec t;
1360 unsigned int uninitialized_var(serial);
1361 int reserve = 5; /* Allow atomic callers to go up to five
1362 entries over the normal backlog limit */
1363 unsigned long timeout_start = jiffies;
1364
1365 if (audit_initialized != AUDIT_INITIALIZED)
1366 return NULL;
1367
1368 if (unlikely(audit_filter_type(type)))
1369 return NULL;
1370
1371 if (gfp_mask & __GFP_DIRECT_RECLAIM) {
1372 if (audit_pid && audit_pid == current->tgid)
1373 gfp_mask &= ~__GFP_DIRECT_RECLAIM;
1374 else
1375 reserve = 0;
1376 }
1377
1378 while (audit_backlog_limit
1379 && skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) {
1380 if (gfp_mask & __GFP_DIRECT_RECLAIM && audit_backlog_wait_time) {
1381 long sleep_time;
1382
1383 sleep_time = timeout_start + audit_backlog_wait_time - jiffies;
1384 if (sleep_time > 0) {
1385 sleep_time = wait_for_auditd(sleep_time);
1386 if (sleep_time > 0)
1387 continue;
1388 }
1389 }
1390 if (audit_rate_check() && printk_ratelimit())
1391 pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
1392 skb_queue_len(&audit_skb_queue),
1393 audit_backlog_limit);
1394 audit_log_lost("backlog limit exceeded");
1395 audit_backlog_wait_time = 0;
1396 wake_up(&audit_backlog_wait);
1397 return NULL;
1398 }
1399
1400 if (!reserve && !audit_backlog_wait_time)
1401 audit_backlog_wait_time = audit_backlog_wait_time_master;
1402
1403 ab = audit_buffer_alloc(ctx, gfp_mask, type);
1404 if (!ab) {
1405 audit_log_lost("out of memory in audit_log_start");
1406 return NULL;
1407 }
1408
1409 audit_get_stamp(ab->ctx, &t, &serial);
1410
1411 audit_log_format(ab, "audit(%lu.%03lu:%u): ",
1412 t.tv_sec, t.tv_nsec/1000000, serial);
1413 return ab;
1414}
1415
1416/**
1417 * audit_expand - expand skb in the audit buffer
1418 * @ab: audit_buffer
1419 * @extra: space to add at tail of the skb
1420 *
1421 * Returns 0 (no space) on failed expansion, or available space if
1422 * successful.
1423 */
1424static inline int audit_expand(struct audit_buffer *ab, int extra)
1425{
1426 struct sk_buff *skb = ab->skb;
1427 int oldtail = skb_tailroom(skb);
1428 int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1429 int newtail = skb_tailroom(skb);
1430
1431 if (ret < 0) {
1432 audit_log_lost("out of memory in audit_expand");
1433 return 0;
1434 }
1435
1436 skb->truesize += newtail - oldtail;
1437 return newtail;
1438}
1439
1440/*
1441 * Format an audit message into the audit buffer. If there isn't enough
1442 * room in the audit buffer, more room will be allocated and vsnprint
1443 * will be called a second time. Currently, we assume that a printk
1444 * can't format message larger than 1024 bytes, so we don't either.
1445 */
1446static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1447 va_list args)
1448{
1449 int len, avail;
1450 struct sk_buff *skb;
1451 va_list args2;
1452
1453 if (!ab)
1454 return;
1455
1456 BUG_ON(!ab->skb);
1457 skb = ab->skb;
1458 avail = skb_tailroom(skb);
1459 if (avail == 0) {
1460 avail = audit_expand(ab, AUDIT_BUFSIZ);
1461 if (!avail)
1462 goto out;
1463 }
1464 va_copy(args2, args);
1465 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1466 if (len >= avail) {
1467 /* The printk buffer is 1024 bytes long, so if we get
1468 * here and AUDIT_BUFSIZ is at least 1024, then we can
1469 * log everything that printk could have logged. */
1470 avail = audit_expand(ab,
1471 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1472 if (!avail)
1473 goto out_va_end;
1474 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1475 }
1476 if (len > 0)
1477 skb_put(skb, len);
1478out_va_end:
1479 va_end(args2);
1480out:
1481 return;
1482}
1483
1484/**
1485 * audit_log_format - format a message into the audit buffer.
1486 * @ab: audit_buffer
1487 * @fmt: format string
1488 * @...: optional parameters matching @fmt string
1489 *
1490 * All the work is done in audit_log_vformat.
1491 */
1492void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1493{
1494 va_list args;
1495
1496 if (!ab)
1497 return;
1498 va_start(args, fmt);
1499 audit_log_vformat(ab, fmt, args);
1500 va_end(args);
1501}
1502
1503/**
1504 * audit_log_hex - convert a buffer to hex and append it to the audit skb
1505 * @ab: the audit_buffer
1506 * @buf: buffer to convert to hex
1507 * @len: length of @buf to be converted
1508 *
1509 * No return value; failure to expand is silently ignored.
1510 *
1511 * This function will take the passed buf and convert it into a string of
1512 * ascii hex digits. The new string is placed onto the skb.
1513 */
1514void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
1515 size_t len)
1516{
1517 int i, avail, new_len;
1518 unsigned char *ptr;
1519 struct sk_buff *skb;
1520
1521 if (!ab)
1522 return;
1523
1524 BUG_ON(!ab->skb);
1525 skb = ab->skb;
1526 avail = skb_tailroom(skb);
1527 new_len = len<<1;
1528 if (new_len >= avail) {
1529 /* Round the buffer request up to the next multiple */
1530 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1531 avail = audit_expand(ab, new_len);
1532 if (!avail)
1533 return;
1534 }
1535
1536 ptr = skb_tail_pointer(skb);
1537 for (i = 0; i < len; i++)
1538 ptr = hex_byte_pack_upper(ptr, buf[i]);
1539 *ptr = 0;
1540 skb_put(skb, len << 1); /* new string is twice the old string */
1541}
1542
1543/*
1544 * Format a string of no more than slen characters into the audit buffer,
1545 * enclosed in quote marks.
1546 */
1547void audit_log_n_string(struct audit_buffer *ab, const char *string,
1548 size_t slen)
1549{
1550 int avail, new_len;
1551 unsigned char *ptr;
1552 struct sk_buff *skb;
1553
1554 if (!ab)
1555 return;
1556
1557 BUG_ON(!ab->skb);
1558 skb = ab->skb;
1559 avail = skb_tailroom(skb);
1560 new_len = slen + 3; /* enclosing quotes + null terminator */
1561 if (new_len > avail) {
1562 avail = audit_expand(ab, new_len);
1563 if (!avail)
1564 return;
1565 }
1566 ptr = skb_tail_pointer(skb);
1567 *ptr++ = '"';
1568 memcpy(ptr, string, slen);
1569 ptr += slen;
1570 *ptr++ = '"';
1571 *ptr = 0;
1572 skb_put(skb, slen + 2); /* don't include null terminator */
1573}
1574
1575/**
1576 * audit_string_contains_control - does a string need to be logged in hex
1577 * @string: string to be checked
1578 * @len: max length of the string to check
1579 */
1580bool audit_string_contains_control(const char *string, size_t len)
1581{
1582 const unsigned char *p;
1583 for (p = string; p < (const unsigned char *)string + len; p++) {
1584 if (*p == '"' || *p < 0x21 || *p > 0x7e)
1585 return true;
1586 }
1587 return false;
1588}
1589
1590/**
1591 * audit_log_n_untrustedstring - log a string that may contain random characters
1592 * @ab: audit_buffer
1593 * @len: length of string (not including trailing null)
1594 * @string: string to be logged
1595 *
1596 * This code will escape a string that is passed to it if the string
1597 * contains a control character, unprintable character, double quote mark,
1598 * or a space. Unescaped strings will start and end with a double quote mark.
1599 * Strings that are escaped are printed in hex (2 digits per char).
1600 *
1601 * The caller specifies the number of characters in the string to log, which may
1602 * or may not be the entire string.
1603 */
1604void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
1605 size_t len)
1606{
1607 if (audit_string_contains_control(string, len))
1608 audit_log_n_hex(ab, string, len);
1609 else
1610 audit_log_n_string(ab, string, len);
1611}
1612
1613/**
1614 * audit_log_untrustedstring - log a string that may contain random characters
1615 * @ab: audit_buffer
1616 * @string: string to be logged
1617 *
1618 * Same as audit_log_n_untrustedstring(), except that strlen is used to
1619 * determine string length.
1620 */
1621void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
1622{
1623 audit_log_n_untrustedstring(ab, string, strlen(string));
1624}
1625
1626/* This is a helper-function to print the escaped d_path */
1627void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
1628 const struct path *path)
1629{
1630 char *p, *pathname;
1631
1632 if (prefix)
1633 audit_log_format(ab, "%s", prefix);
1634
1635 /* We will allow 11 spaces for ' (deleted)' to be appended */
1636 pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
1637 if (!pathname) {
1638 audit_log_string(ab, "<no_memory>");
1639 return;
1640 }
1641 p = d_path(path, pathname, PATH_MAX+11);
1642 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
1643 /* FIXME: can we save some information here? */
1644 audit_log_string(ab, "<too_long>");
1645 } else
1646 audit_log_untrustedstring(ab, p);
1647 kfree(pathname);
1648}
1649
1650void audit_log_session_info(struct audit_buffer *ab)
1651{
1652 unsigned int sessionid = audit_get_sessionid(current);
1653 uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
1654
1655 audit_log_format(ab, " auid=%u ses=%u", auid, sessionid);
1656}
1657
1658void audit_log_key(struct audit_buffer *ab, char *key)
1659{
1660 audit_log_format(ab, " key=");
1661 if (key)
1662 audit_log_untrustedstring(ab, key);
1663 else
1664 audit_log_format(ab, "(null)");
1665}
1666
1667void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap)
1668{
1669 int i;
1670
1671 audit_log_format(ab, " %s=", prefix);
1672 CAP_FOR_EACH_U32(i) {
1673 audit_log_format(ab, "%08x",
1674 cap->cap[CAP_LAST_U32 - i]);
1675 }
1676}
1677
1678static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
1679{
1680 kernel_cap_t *perm = &name->fcap.permitted;
1681 kernel_cap_t *inh = &name->fcap.inheritable;
1682 int log = 0;
1683
1684 if (!cap_isclear(*perm)) {
1685 audit_log_cap(ab, "cap_fp", perm);
1686 log = 1;
1687 }
1688 if (!cap_isclear(*inh)) {
1689 audit_log_cap(ab, "cap_fi", inh);
1690 log = 1;
1691 }
1692
1693 if (log)
1694 audit_log_format(ab, " cap_fe=%d cap_fver=%x",
1695 name->fcap.fE, name->fcap_ver);
1696}
1697
1698static inline int audit_copy_fcaps(struct audit_names *name,
1699 const struct dentry *dentry)
1700{
1701 struct cpu_vfs_cap_data caps;
1702 int rc;
1703
1704 if (!dentry)
1705 return 0;
1706
1707 rc = get_vfs_caps_from_disk(dentry, &caps);
1708 if (rc)
1709 return rc;
1710
1711 name->fcap.permitted = caps.permitted;
1712 name->fcap.inheritable = caps.inheritable;
1713 name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
1714 name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >>
1715 VFS_CAP_REVISION_SHIFT;
1716
1717 return 0;
1718}
1719
1720/* Copy inode data into an audit_names. */
1721void audit_copy_inode(struct audit_names *name, const struct dentry *dentry,
1722 struct inode *inode)
1723{
1724 name->ino = inode->i_ino;
1725 name->dev = inode->i_sb->s_dev;
1726 name->mode = inode->i_mode;
1727 name->uid = inode->i_uid;
1728 name->gid = inode->i_gid;
1729 name->rdev = inode->i_rdev;
1730 security_inode_getsecid(inode, &name->osid);
1731 audit_copy_fcaps(name, dentry);
1732}
1733
1734/**
1735 * audit_log_name - produce AUDIT_PATH record from struct audit_names
1736 * @context: audit_context for the task
1737 * @n: audit_names structure with reportable details
1738 * @path: optional path to report instead of audit_names->name
1739 * @record_num: record number to report when handling a list of names
1740 * @call_panic: optional pointer to int that will be updated if secid fails
1741 */
1742void audit_log_name(struct audit_context *context, struct audit_names *n,
1743 struct path *path, int record_num, int *call_panic)
1744{
1745 struct audit_buffer *ab;
1746 ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH);
1747 if (!ab)
1748 return;
1749
1750 audit_log_format(ab, "item=%d", record_num);
1751
1752 if (path)
1753 audit_log_d_path(ab, " name=", path);
1754 else if (n->name) {
1755 switch (n->name_len) {
1756 case AUDIT_NAME_FULL:
1757 /* log the full path */
1758 audit_log_format(ab, " name=");
1759 audit_log_untrustedstring(ab, n->name->name);
1760 break;
1761 case 0:
1762 /* name was specified as a relative path and the
1763 * directory component is the cwd */
1764 audit_log_d_path(ab, " name=", &context->pwd);
1765 break;
1766 default:
1767 /* log the name's directory component */
1768 audit_log_format(ab, " name=");
1769 audit_log_n_untrustedstring(ab, n->name->name,
1770 n->name_len);
1771 }
1772 } else
1773 audit_log_format(ab, " name=(null)");
1774
1775 if (n->ino != AUDIT_INO_UNSET)
1776 audit_log_format(ab, " inode=%lu"
1777 " dev=%02x:%02x mode=%#ho"
1778 " ouid=%u ogid=%u rdev=%02x:%02x",
1779 n->ino,
1780 MAJOR(n->dev),
1781 MINOR(n->dev),
1782 n->mode,
1783 from_kuid(&init_user_ns, n->uid),
1784 from_kgid(&init_user_ns, n->gid),
1785 MAJOR(n->rdev),
1786 MINOR(n->rdev));
1787 if (n->osid != 0) {
1788 char *ctx = NULL;
1789 u32 len;
1790 if (security_secid_to_secctx(
1791 n->osid, &ctx, &len)) {
1792 audit_log_format(ab, " osid=%u", n->osid);
1793 if (call_panic)
1794 *call_panic = 2;
1795 } else {
1796 audit_log_format(ab, " obj=%s", ctx);
1797 security_release_secctx(ctx, len);
1798 }
1799 }
1800
1801 /* log the audit_names record type */
1802 audit_log_format(ab, " nametype=");
1803 switch(n->type) {
1804 case AUDIT_TYPE_NORMAL:
1805 audit_log_format(ab, "NORMAL");
1806 break;
1807 case AUDIT_TYPE_PARENT:
1808 audit_log_format(ab, "PARENT");
1809 break;
1810 case AUDIT_TYPE_CHILD_DELETE:
1811 audit_log_format(ab, "DELETE");
1812 break;
1813 case AUDIT_TYPE_CHILD_CREATE:
1814 audit_log_format(ab, "CREATE");
1815 break;
1816 default:
1817 audit_log_format(ab, "UNKNOWN");
1818 break;
1819 }
1820
1821 audit_log_fcaps(ab, n);
1822 audit_log_end(ab);
1823}
1824
1825int audit_log_task_context(struct audit_buffer *ab)
1826{
1827 char *ctx = NULL;
1828 unsigned len;
1829 int error;
1830 u32 sid;
1831
1832 security_task_getsecid(current, &sid);
1833 if (!sid)
1834 return 0;
1835
1836 error = security_secid_to_secctx(sid, &ctx, &len);
1837 if (error) {
1838 if (error != -EINVAL)
1839 goto error_path;
1840 return 0;
1841 }
1842
1843 audit_log_format(ab, " subj=%s", ctx);
1844 security_release_secctx(ctx, len);
1845 return 0;
1846
1847error_path:
1848 audit_panic("error in audit_log_task_context");
1849 return error;
1850}
1851EXPORT_SYMBOL(audit_log_task_context);
1852
1853void audit_log_d_path_exe(struct audit_buffer *ab,
1854 struct mm_struct *mm)
1855{
1856 struct file *exe_file;
1857
1858 if (!mm)
1859 goto out_null;
1860
1861 exe_file = get_mm_exe_file(mm);
1862 if (!exe_file)
1863 goto out_null;
1864
1865 audit_log_d_path(ab, " exe=", &exe_file->f_path);
1866 fput(exe_file);
1867 return;
1868out_null:
1869 audit_log_format(ab, " exe=(null)");
1870}
1871
1872void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
1873{
1874 const struct cred *cred;
1875 char comm[sizeof(tsk->comm)];
1876 char *tty;
1877
1878 if (!ab)
1879 return;
1880
1881 /* tsk == current */
1882 cred = current_cred();
1883
1884 spin_lock_irq(&tsk->sighand->siglock);
1885 if (tsk->signal && tsk->signal->tty && tsk->signal->tty->name)
1886 tty = tsk->signal->tty->name;
1887 else
1888 tty = "(none)";
1889 spin_unlock_irq(&tsk->sighand->siglock);
1890
1891 audit_log_format(ab,
1892 " ppid=%d pid=%d auid=%u uid=%u gid=%u"
1893 " euid=%u suid=%u fsuid=%u"
1894 " egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
1895 task_ppid_nr(tsk),
1896 task_pid_nr(tsk),
1897 from_kuid(&init_user_ns, audit_get_loginuid(tsk)),
1898 from_kuid(&init_user_ns, cred->uid),
1899 from_kgid(&init_user_ns, cred->gid),
1900 from_kuid(&init_user_ns, cred->euid),
1901 from_kuid(&init_user_ns, cred->suid),
1902 from_kuid(&init_user_ns, cred->fsuid),
1903 from_kgid(&init_user_ns, cred->egid),
1904 from_kgid(&init_user_ns, cred->sgid),
1905 from_kgid(&init_user_ns, cred->fsgid),
1906 tty, audit_get_sessionid(tsk));
1907
1908 audit_log_format(ab, " comm=");
1909 audit_log_untrustedstring(ab, get_task_comm(comm, tsk));
1910
1911 audit_log_d_path_exe(ab, tsk->mm);
1912 audit_log_task_context(ab);
1913}
1914EXPORT_SYMBOL(audit_log_task_info);
1915
1916/**
1917 * audit_log_link_denied - report a link restriction denial
1918 * @operation: specific link operation
1919 * @link: the path that triggered the restriction
1920 */
1921void audit_log_link_denied(const char *operation, struct path *link)
1922{
1923 struct audit_buffer *ab;
1924 struct audit_names *name;
1925
1926 name = kzalloc(sizeof(*name), GFP_NOFS);
1927 if (!name)
1928 return;
1929
1930 /* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */
1931 ab = audit_log_start(current->audit_context, GFP_KERNEL,
1932 AUDIT_ANOM_LINK);
1933 if (!ab)
1934 goto out;
1935 audit_log_format(ab, "op=%s", operation);
1936 audit_log_task_info(ab, current);
1937 audit_log_format(ab, " res=0");
1938 audit_log_end(ab);
1939
1940 /* Generate AUDIT_PATH record with object. */
1941 name->type = AUDIT_TYPE_NORMAL;
1942 audit_copy_inode(name, link->dentry, d_backing_inode(link->dentry));
1943 audit_log_name(current->audit_context, name, link, 0, NULL);
1944out:
1945 kfree(name);
1946}
1947
1948/**
1949 * audit_log_end - end one audit record
1950 * @ab: the audit_buffer
1951 *
1952 * netlink_unicast() cannot be called inside an irq context because it blocks
1953 * (last arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed
1954 * on a queue and a tasklet is scheduled to remove them from the queue outside
1955 * the irq context. May be called in any context.
1956 */
1957void audit_log_end(struct audit_buffer *ab)
1958{
1959 if (!ab)
1960 return;
1961 if (!audit_rate_check()) {
1962 audit_log_lost("rate limit exceeded");
1963 } else {
1964 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
1965
1966 nlh->nlmsg_len = ab->skb->len;
1967 kauditd_send_multicast_skb(ab->skb, ab->gfp_mask);
1968
1969 /*
1970 * The original kaudit unicast socket sends up messages with
1971 * nlmsg_len set to the payload length rather than the entire
1972 * message length. This breaks the standard set by netlink.
1973 * The existing auditd daemon assumes this breakage. Fixing
1974 * this would require co-ordinating a change in the established
1975 * protocol between the kaudit kernel subsystem and the auditd
1976 * userspace code.
1977 */
1978 nlh->nlmsg_len -= NLMSG_HDRLEN;
1979
1980 if (audit_pid) {
1981 skb_queue_tail(&audit_skb_queue, ab->skb);
1982 wake_up_interruptible(&kauditd_wait);
1983 } else {
1984 audit_printk_skb(ab->skb);
1985 }
1986 ab->skb = NULL;
1987 }
1988 audit_buffer_free(ab);
1989}
1990
1991/**
1992 * audit_log - Log an audit record
1993 * @ctx: audit context
1994 * @gfp_mask: type of allocation
1995 * @type: audit message type
1996 * @fmt: format string to use
1997 * @...: variable parameters matching the format string
1998 *
1999 * This is a convenience function that calls audit_log_start,
2000 * audit_log_vformat, and audit_log_end. It may be called
2001 * in any context.
2002 */
2003void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
2004 const char *fmt, ...)
2005{
2006 struct audit_buffer *ab;
2007 va_list args;
2008
2009 ab = audit_log_start(ctx, gfp_mask, type);
2010 if (ab) {
2011 va_start(args, fmt);
2012 audit_log_vformat(ab, fmt, args);
2013 va_end(args);
2014 audit_log_end(ab);
2015 }
2016}
2017
2018#ifdef CONFIG_SECURITY
2019/**
2020 * audit_log_secctx - Converts and logs SELinux context
2021 * @ab: audit_buffer
2022 * @secid: security number
2023 *
2024 * This is a helper function that calls security_secid_to_secctx to convert
2025 * secid to secctx and then adds the (converted) SELinux context to the audit
2026 * log by calling audit_log_format, thus also preventing leak of internal secid
2027 * to userspace. If secid cannot be converted audit_panic is called.
2028 */
2029void audit_log_secctx(struct audit_buffer *ab, u32 secid)
2030{
2031 u32 len;
2032 char *secctx;
2033
2034 if (security_secid_to_secctx(secid, &secctx, &len)) {
2035 audit_panic("Cannot convert secid to context");
2036 } else {
2037 audit_log_format(ab, " obj=%s", secctx);
2038 security_release_secctx(secctx, len);
2039 }
2040}
2041EXPORT_SYMBOL(audit_log_secctx);
2042#endif
2043
2044EXPORT_SYMBOL(audit_log_start);
2045EXPORT_SYMBOL(audit_log_end);
2046EXPORT_SYMBOL(audit_log_format);
2047EXPORT_SYMBOL(audit_log);