projects/linux·blob v3.12 · 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#include <linux/init.h>
45#include <asm/types.h>
46#include <linux/atomic.h>
47#include <linux/mm.h>
48#include <linux/export.h>
49#include <linux/slab.h>
50#include <linux/err.h>
51#include <linux/kthread.h>
52#include <linux/kernel.h>
53#include <linux/syscalls.h>
54
55#include <linux/audit.h>
56
57#include <net/sock.h>
58#include <net/netlink.h>
59#include <linux/skbuff.h>
60#ifdef CONFIG_SECURITY
61#include <linux/security.h>
62#endif
63#include <net/netlink.h>
64#include <linux/freezer.h>
65#include <linux/tty.h>
66#include <linux/pid_namespace.h>
67
68#include "audit.h"
69
70/* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
71 * (Initialization happens after skb_init is called.) */
72#define AUDIT_DISABLED -1
73#define AUDIT_UNINITIALIZED 0
74#define AUDIT_INITIALIZED 1
75static int audit_initialized;
76
77#define AUDIT_OFF 0
78#define AUDIT_ON 1
79#define AUDIT_LOCKED 2
80int audit_enabled;
81int audit_ever_enabled;
82
83EXPORT_SYMBOL_GPL(audit_enabled);
84
85/* Default state when kernel boots without any parameters. */
86static int audit_default;
87
88/* If auditing cannot proceed, audit_failure selects what happens. */
89static int audit_failure = AUDIT_FAIL_PRINTK;
90
91/*
92 * If audit records are to be written to the netlink socket, audit_pid
93 * contains the pid of the auditd process and audit_nlk_portid contains
94 * the portid to use to send netlink messages to that process.
95 */
96int audit_pid;
97static int audit_nlk_portid;
98
99/* If audit_rate_limit is non-zero, limit the rate of sending audit records
100 * to that number per second. This prevents DoS attacks, but results in
101 * audit records being dropped. */
102static int audit_rate_limit;
103
104/* Number of outstanding audit_buffers allowed. */
105static int audit_backlog_limit = 64;
106static int audit_backlog_wait_time = 60 * HZ;
107static int audit_backlog_wait_overflow = 0;
108
109/* The identity of the user shutting down the audit system. */
110kuid_t audit_sig_uid = INVALID_UID;
111pid_t audit_sig_pid = -1;
112u32 audit_sig_sid = 0;
113
114/* Records can be lost in several ways:
115 0) [suppressed in audit_alloc]
116 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
117 2) out of memory in audit_log_move [alloc_skb]
118 3) suppressed due to audit_rate_limit
119 4) suppressed due to audit_backlog_limit
120*/
121static atomic_t audit_lost = ATOMIC_INIT(0);
122
123/* The netlink socket. */
124static struct sock *audit_sock;
125
126/* Hash for inode-based rules */
127struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
128
129/* The audit_freelist is a list of pre-allocated audit buffers (if more
130 * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
131 * being placed on the freelist). */
132static DEFINE_SPINLOCK(audit_freelist_lock);
133static int audit_freelist_count;
134static LIST_HEAD(audit_freelist);
135
136static struct sk_buff_head audit_skb_queue;
137/* queue of skbs to send to auditd when/if it comes back */
138static struct sk_buff_head audit_skb_hold_queue;
139static struct task_struct *kauditd_task;
140static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
141static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
142
143/* Serialize requests from userspace. */
144DEFINE_MUTEX(audit_cmd_mutex);
145
146/* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
147 * audit records. Since printk uses a 1024 byte buffer, this buffer
148 * should be at least that large. */
149#define AUDIT_BUFSIZ 1024
150
151/* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the
152 * audit_freelist. Doing so eliminates many kmalloc/kfree calls. */
153#define AUDIT_MAXFREE (2*NR_CPUS)
154
155/* The audit_buffer is used when formatting an audit record. The caller
156 * locks briefly to get the record off the freelist or to allocate the
157 * buffer, and locks briefly to send the buffer to the netlink layer or
158 * to place it on a transmit queue. Multiple audit_buffers can be in
159 * use simultaneously. */
160struct audit_buffer {
161 struct list_head list;
162 struct sk_buff *skb; /* formatted skb ready to send */
163 struct audit_context *ctx; /* NULL or associated context */
164 gfp_t gfp_mask;
165};
166
167struct audit_reply {
168 int pid;
169 struct sk_buff *skb;
170};
171
172static void audit_set_pid(struct audit_buffer *ab, pid_t pid)
173{
174 if (ab) {
175 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
176 nlh->nlmsg_pid = pid;
177 }
178}
179
180void audit_panic(const char *message)
181{
182 switch (audit_failure)
183 {
184 case AUDIT_FAIL_SILENT:
185 break;
186 case AUDIT_FAIL_PRINTK:
187 if (printk_ratelimit())
188 printk(KERN_ERR "audit: %s\n", message);
189 break;
190 case AUDIT_FAIL_PANIC:
191 /* test audit_pid since printk is always losey, why bother? */
192 if (audit_pid)
193 panic("audit: %s\n", message);
194 break;
195 }
196}
197
198static inline int audit_rate_check(void)
199{
200 static unsigned long last_check = 0;
201 static int messages = 0;
202 static DEFINE_SPINLOCK(lock);
203 unsigned long flags;
204 unsigned long now;
205 unsigned long elapsed;
206 int retval = 0;
207
208 if (!audit_rate_limit) return 1;
209
210 spin_lock_irqsave(&lock, flags);
211 if (++messages < audit_rate_limit) {
212 retval = 1;
213 } else {
214 now = jiffies;
215 elapsed = now - last_check;
216 if (elapsed > HZ) {
217 last_check = now;
218 messages = 0;
219 retval = 1;
220 }
221 }
222 spin_unlock_irqrestore(&lock, flags);
223
224 return retval;
225}
226
227/**
228 * audit_log_lost - conditionally log lost audit message event
229 * @message: the message stating reason for lost audit message
230 *
231 * Emit at least 1 message per second, even if audit_rate_check is
232 * throttling.
233 * Always increment the lost messages counter.
234*/
235void audit_log_lost(const char *message)
236{
237 static unsigned long last_msg = 0;
238 static DEFINE_SPINLOCK(lock);
239 unsigned long flags;
240 unsigned long now;
241 int print;
242
243 atomic_inc(&audit_lost);
244
245 print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
246
247 if (!print) {
248 spin_lock_irqsave(&lock, flags);
249 now = jiffies;
250 if (now - last_msg > HZ) {
251 print = 1;
252 last_msg = now;
253 }
254 spin_unlock_irqrestore(&lock, flags);
255 }
256
257 if (print) {
258 if (printk_ratelimit())
259 printk(KERN_WARNING
260 "audit: audit_lost=%d audit_rate_limit=%d "
261 "audit_backlog_limit=%d\n",
262 atomic_read(&audit_lost),
263 audit_rate_limit,
264 audit_backlog_limit);
265 audit_panic(message);
266 }
267}
268
269static int audit_log_config_change(char *function_name, int new, int old,
270 int allow_changes)
271{
272 struct audit_buffer *ab;
273 int rc = 0;
274
275 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
276 if (unlikely(!ab))
277 return rc;
278 audit_log_format(ab, "%s=%d old=%d", function_name, new, old);
279 audit_log_session_info(ab);
280 rc = audit_log_task_context(ab);
281 if (rc)
282 allow_changes = 0; /* Something weird, deny request */
283 audit_log_format(ab, " res=%d", allow_changes);
284 audit_log_end(ab);
285 return rc;
286}
287
288static int audit_do_config_change(char *function_name, int *to_change, int new)
289{
290 int allow_changes, rc = 0, old = *to_change;
291
292 /* check if we are locked */
293 if (audit_enabled == AUDIT_LOCKED)
294 allow_changes = 0;
295 else
296 allow_changes = 1;
297
298 if (audit_enabled != AUDIT_OFF) {
299 rc = audit_log_config_change(function_name, new, old, allow_changes);
300 if (rc)
301 allow_changes = 0;
302 }
303
304 /* If we are allowed, make the change */
305 if (allow_changes == 1)
306 *to_change = new;
307 /* Not allowed, update reason */
308 else if (rc == 0)
309 rc = -EPERM;
310 return rc;
311}
312
313static int audit_set_rate_limit(int limit)
314{
315 return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit);
316}
317
318static int audit_set_backlog_limit(int limit)
319{
320 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit);
321}
322
323static int audit_set_enabled(int state)
324{
325 int rc;
326 if (state < AUDIT_OFF || state > AUDIT_LOCKED)
327 return -EINVAL;
328
329 rc = audit_do_config_change("audit_enabled", &audit_enabled, state);
330 if (!rc)
331 audit_ever_enabled |= !!state;
332
333 return rc;
334}
335
336static int audit_set_failure(int state)
337{
338 if (state != AUDIT_FAIL_SILENT
339 && state != AUDIT_FAIL_PRINTK
340 && state != AUDIT_FAIL_PANIC)
341 return -EINVAL;
342
343 return audit_do_config_change("audit_failure", &audit_failure, state);
344}
345
346/*
347 * Queue skbs to be sent to auditd when/if it comes back. These skbs should
348 * already have been sent via prink/syslog and so if these messages are dropped
349 * it is not a huge concern since we already passed the audit_log_lost()
350 * notification and stuff. This is just nice to get audit messages during
351 * boot before auditd is running or messages generated while auditd is stopped.
352 * This only holds messages is audit_default is set, aka booting with audit=1
353 * or building your kernel that way.
354 */
355static void audit_hold_skb(struct sk_buff *skb)
356{
357 if (audit_default &&
358 skb_queue_len(&audit_skb_hold_queue) < audit_backlog_limit)
359 skb_queue_tail(&audit_skb_hold_queue, skb);
360 else
361 kfree_skb(skb);
362}
363
364/*
365 * For one reason or another this nlh isn't getting delivered to the userspace
366 * audit daemon, just send it to printk.
367 */
368static void audit_printk_skb(struct sk_buff *skb)
369{
370 struct nlmsghdr *nlh = nlmsg_hdr(skb);
371 char *data = nlmsg_data(nlh);
372
373 if (nlh->nlmsg_type != AUDIT_EOE) {
374 if (printk_ratelimit())
375 printk(KERN_NOTICE "type=%d %s\n", nlh->nlmsg_type, data);
376 else
377 audit_log_lost("printk limit exceeded\n");
378 }
379
380 audit_hold_skb(skb);
381}
382
383static void kauditd_send_skb(struct sk_buff *skb)
384{
385 int err;
386 /* take a reference in case we can't send it and we want to hold it */
387 skb_get(skb);
388 err = netlink_unicast(audit_sock, skb, audit_nlk_portid, 0);
389 if (err < 0) {
390 BUG_ON(err != -ECONNREFUSED); /* Shouldn't happen */
391 printk(KERN_ERR "audit: *NO* daemon at audit_pid=%d\n", audit_pid);
392 audit_log_lost("auditd disappeared\n");
393 audit_pid = 0;
394 /* we might get lucky and get this in the next auditd */
395 audit_hold_skb(skb);
396 } else
397 /* drop the extra reference if sent ok */
398 consume_skb(skb);
399}
400
401/*
402 * flush_hold_queue - empty the hold queue if auditd appears
403 *
404 * If auditd just started, drain the queue of messages already
405 * sent to syslog/printk. Remember loss here is ok. We already
406 * called audit_log_lost() if it didn't go out normally. so the
407 * race between the skb_dequeue and the next check for audit_pid
408 * doesn't matter.
409 *
410 * If you ever find kauditd to be too slow we can get a perf win
411 * by doing our own locking and keeping better track if there
412 * are messages in this queue. I don't see the need now, but
413 * in 5 years when I want to play with this again I'll see this
414 * note and still have no friggin idea what i'm thinking today.
415 */
416static void flush_hold_queue(void)
417{
418 struct sk_buff *skb;
419
420 if (!audit_default || !audit_pid)
421 return;
422
423 skb = skb_dequeue(&audit_skb_hold_queue);
424 if (likely(!skb))
425 return;
426
427 while (skb && audit_pid) {
428 kauditd_send_skb(skb);
429 skb = skb_dequeue(&audit_skb_hold_queue);
430 }
431
432 /*
433 * if auditd just disappeared but we
434 * dequeued an skb we need to drop ref
435 */
436 if (skb)
437 consume_skb(skb);
438}
439
440static int kauditd_thread(void *dummy)
441{
442 set_freezable();
443 while (!kthread_should_stop()) {
444 struct sk_buff *skb;
445 DECLARE_WAITQUEUE(wait, current);
446
447 flush_hold_queue();
448
449 skb = skb_dequeue(&audit_skb_queue);
450 wake_up(&audit_backlog_wait);
451 if (skb) {
452 if (audit_pid)
453 kauditd_send_skb(skb);
454 else
455 audit_printk_skb(skb);
456 continue;
457 }
458 set_current_state(TASK_INTERRUPTIBLE);
459 add_wait_queue(&kauditd_wait, &wait);
460
461 if (!skb_queue_len(&audit_skb_queue)) {
462 try_to_freeze();
463 schedule();
464 }
465
466 __set_current_state(TASK_RUNNING);
467 remove_wait_queue(&kauditd_wait, &wait);
468 }
469 return 0;
470}
471
472int audit_send_list(void *_dest)
473{
474 struct audit_netlink_list *dest = _dest;
475 int pid = dest->pid;
476 struct sk_buff *skb;
477
478 /* wait for parent to finish and send an ACK */
479 mutex_lock(&audit_cmd_mutex);
480 mutex_unlock(&audit_cmd_mutex);
481
482 while ((skb = __skb_dequeue(&dest->q)) != NULL)
483 netlink_unicast(audit_sock, skb, pid, 0);
484
485 kfree(dest);
486
487 return 0;
488}
489
490struct sk_buff *audit_make_reply(int pid, int seq, int type, int done,
491 int multi, const void *payload, int size)
492{
493 struct sk_buff *skb;
494 struct nlmsghdr *nlh;
495 void *data;
496 int flags = multi ? NLM_F_MULTI : 0;
497 int t = done ? NLMSG_DONE : type;
498
499 skb = nlmsg_new(size, GFP_KERNEL);
500 if (!skb)
501 return NULL;
502
503 nlh = nlmsg_put(skb, pid, seq, t, size, flags);
504 if (!nlh)
505 goto out_kfree_skb;
506 data = nlmsg_data(nlh);
507 memcpy(data, payload, size);
508 return skb;
509
510out_kfree_skb:
511 kfree_skb(skb);
512 return NULL;
513}
514
515static int audit_send_reply_thread(void *arg)
516{
517 struct audit_reply *reply = (struct audit_reply *)arg;
518
519 mutex_lock(&audit_cmd_mutex);
520 mutex_unlock(&audit_cmd_mutex);
521
522 /* Ignore failure. It'll only happen if the sender goes away,
523 because our timeout is set to infinite. */
524 netlink_unicast(audit_sock, reply->skb, reply->pid, 0);
525 kfree(reply);
526 return 0;
527}
528/**
529 * audit_send_reply - send an audit reply message via netlink
530 * @pid: process id to send reply to
531 * @seq: sequence number
532 * @type: audit message type
533 * @done: done (last) flag
534 * @multi: multi-part message flag
535 * @payload: payload data
536 * @size: payload size
537 *
538 * Allocates an skb, builds the netlink message, and sends it to the pid.
539 * No failure notifications.
540 */
541static void audit_send_reply(int pid, int seq, int type, int done, int multi,
542 const void *payload, int size)
543{
544 struct sk_buff *skb;
545 struct task_struct *tsk;
546 struct audit_reply *reply = kmalloc(sizeof(struct audit_reply),
547 GFP_KERNEL);
548
549 if (!reply)
550 return;
551
552 skb = audit_make_reply(pid, seq, type, done, multi, payload, size);
553 if (!skb)
554 goto out;
555
556 reply->pid = pid;
557 reply->skb = skb;
558
559 tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
560 if (!IS_ERR(tsk))
561 return;
562 kfree_skb(skb);
563out:
564 kfree(reply);
565}
566
567/*
568 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
569 * control messages.
570 */
571static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
572{
573 int err = 0;
574
575 /* Only support the initial namespaces for now. */
576 if ((current_user_ns() != &init_user_ns) ||
577 (task_active_pid_ns(current) != &init_pid_ns))
578 return -EPERM;
579
580 switch (msg_type) {
581 case AUDIT_LIST:
582 case AUDIT_ADD:
583 case AUDIT_DEL:
584 return -EOPNOTSUPP;
585 case AUDIT_GET:
586 case AUDIT_SET:
587 case AUDIT_LIST_RULES:
588 case AUDIT_ADD_RULE:
589 case AUDIT_DEL_RULE:
590 case AUDIT_SIGNAL_INFO:
591 case AUDIT_TTY_GET:
592 case AUDIT_TTY_SET:
593 case AUDIT_TRIM:
594 case AUDIT_MAKE_EQUIV:
595 if (!capable(CAP_AUDIT_CONTROL))
596 err = -EPERM;
597 break;
598 case AUDIT_USER:
599 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
600 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
601 if (!capable(CAP_AUDIT_WRITE))
602 err = -EPERM;
603 break;
604 default: /* bad msg */
605 err = -EINVAL;
606 }
607
608 return err;
609}
610
611static int audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
612{
613 int rc = 0;
614 uid_t uid = from_kuid(&init_user_ns, current_uid());
615
616 if (!audit_enabled) {
617 *ab = NULL;
618 return rc;
619 }
620
621 *ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
622 if (unlikely(!*ab))
623 return rc;
624 audit_log_format(*ab, "pid=%d uid=%u", task_tgid_vnr(current), uid);
625 audit_log_session_info(*ab);
626 audit_log_task_context(*ab);
627
628 return rc;
629}
630
631static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
632{
633 u32 seq;
634 void *data;
635 struct audit_status *status_get, status_set;
636 int err;
637 struct audit_buffer *ab;
638 u16 msg_type = nlh->nlmsg_type;
639 struct audit_sig_info *sig_data;
640 char *ctx = NULL;
641 u32 len;
642
643 err = audit_netlink_ok(skb, msg_type);
644 if (err)
645 return err;
646
647 /* As soon as there's any sign of userspace auditd,
648 * start kauditd to talk to it */
649 if (!kauditd_task) {
650 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
651 if (IS_ERR(kauditd_task)) {
652 err = PTR_ERR(kauditd_task);
653 kauditd_task = NULL;
654 return err;
655 }
656 }
657 seq = nlh->nlmsg_seq;
658 data = nlmsg_data(nlh);
659
660 switch (msg_type) {
661 case AUDIT_GET:
662 status_set.enabled = audit_enabled;
663 status_set.failure = audit_failure;
664 status_set.pid = audit_pid;
665 status_set.rate_limit = audit_rate_limit;
666 status_set.backlog_limit = audit_backlog_limit;
667 status_set.lost = atomic_read(&audit_lost);
668 status_set.backlog = skb_queue_len(&audit_skb_queue);
669 audit_send_reply(NETLINK_CB(skb).portid, seq, AUDIT_GET, 0, 0,
670 &status_set, sizeof(status_set));
671 break;
672 case AUDIT_SET:
673 if (nlh->nlmsg_len < sizeof(struct audit_status))
674 return -EINVAL;
675 status_get = (struct audit_status *)data;
676 if (status_get->mask & AUDIT_STATUS_ENABLED) {
677 err = audit_set_enabled(status_get->enabled);
678 if (err < 0)
679 return err;
680 }
681 if (status_get->mask & AUDIT_STATUS_FAILURE) {
682 err = audit_set_failure(status_get->failure);
683 if (err < 0)
684 return err;
685 }
686 if (status_get->mask & AUDIT_STATUS_PID) {
687 int new_pid = status_get->pid;
688
689 if (audit_enabled != AUDIT_OFF)
690 audit_log_config_change("audit_pid", new_pid, audit_pid, 1);
691 audit_pid = new_pid;
692 audit_nlk_portid = NETLINK_CB(skb).portid;
693 }
694 if (status_get->mask & AUDIT_STATUS_RATE_LIMIT) {
695 err = audit_set_rate_limit(status_get->rate_limit);
696 if (err < 0)
697 return err;
698 }
699 if (status_get->mask & AUDIT_STATUS_BACKLOG_LIMIT)
700 err = audit_set_backlog_limit(status_get->backlog_limit);
701 break;
702 case AUDIT_USER:
703 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
704 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
705 if (!audit_enabled && msg_type != AUDIT_USER_AVC)
706 return 0;
707
708 err = audit_filter_user(msg_type);
709 if (err == 1) {
710 err = 0;
711 if (msg_type == AUDIT_USER_TTY) {
712 err = tty_audit_push_current();
713 if (err)
714 break;
715 }
716 audit_log_common_recv_msg(&ab, msg_type);
717 if (msg_type != AUDIT_USER_TTY)
718 audit_log_format(ab, " msg='%.1024s'",
719 (char *)data);
720 else {
721 int size;
722
723 audit_log_format(ab, " data=");
724 size = nlmsg_len(nlh);
725 if (size > 0 &&
726 ((unsigned char *)data)[size - 1] == '\0')
727 size--;
728 audit_log_n_untrustedstring(ab, data, size);
729 }
730 audit_set_pid(ab, NETLINK_CB(skb).portid);
731 audit_log_end(ab);
732 }
733 break;
734 case AUDIT_ADD_RULE:
735 case AUDIT_DEL_RULE:
736 if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
737 return -EINVAL;
738 if (audit_enabled == AUDIT_LOCKED) {
739 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
740 audit_log_format(ab, " audit_enabled=%d res=0", audit_enabled);
741 audit_log_end(ab);
742 return -EPERM;
743 }
744 /* fallthrough */
745 case AUDIT_LIST_RULES:
746 err = audit_receive_filter(msg_type, NETLINK_CB(skb).portid,
747 seq, data, nlmsg_len(nlh));
748 break;
749 case AUDIT_TRIM:
750 audit_trim_trees();
751 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
752 audit_log_format(ab, " op=trim res=1");
753 audit_log_end(ab);
754 break;
755 case AUDIT_MAKE_EQUIV: {
756 void *bufp = data;
757 u32 sizes[2];
758 size_t msglen = nlmsg_len(nlh);
759 char *old, *new;
760
761 err = -EINVAL;
762 if (msglen < 2 * sizeof(u32))
763 break;
764 memcpy(sizes, bufp, 2 * sizeof(u32));
765 bufp += 2 * sizeof(u32);
766 msglen -= 2 * sizeof(u32);
767 old = audit_unpack_string(&bufp, &msglen, sizes[0]);
768 if (IS_ERR(old)) {
769 err = PTR_ERR(old);
770 break;
771 }
772 new = audit_unpack_string(&bufp, &msglen, sizes[1]);
773 if (IS_ERR(new)) {
774 err = PTR_ERR(new);
775 kfree(old);
776 break;
777 }
778 /* OK, here comes... */
779 err = audit_tag_tree(old, new);
780
781 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
782
783 audit_log_format(ab, " op=make_equiv old=");
784 audit_log_untrustedstring(ab, old);
785 audit_log_format(ab, " new=");
786 audit_log_untrustedstring(ab, new);
787 audit_log_format(ab, " res=%d", !err);
788 audit_log_end(ab);
789 kfree(old);
790 kfree(new);
791 break;
792 }
793 case AUDIT_SIGNAL_INFO:
794 len = 0;
795 if (audit_sig_sid) {
796 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
797 if (err)
798 return err;
799 }
800 sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
801 if (!sig_data) {
802 if (audit_sig_sid)
803 security_release_secctx(ctx, len);
804 return -ENOMEM;
805 }
806 sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
807 sig_data->pid = audit_sig_pid;
808 if (audit_sig_sid) {
809 memcpy(sig_data->ctx, ctx, len);
810 security_release_secctx(ctx, len);
811 }
812 audit_send_reply(NETLINK_CB(skb).portid, seq, AUDIT_SIGNAL_INFO,
813 0, 0, sig_data, sizeof(*sig_data) + len);
814 kfree(sig_data);
815 break;
816 case AUDIT_TTY_GET: {
817 struct audit_tty_status s;
818 struct task_struct *tsk = current;
819
820 spin_lock(&tsk->sighand->siglock);
821 s.enabled = tsk->signal->audit_tty != 0;
822 s.log_passwd = tsk->signal->audit_tty_log_passwd;
823 spin_unlock(&tsk->sighand->siglock);
824
825 audit_send_reply(NETLINK_CB(skb).portid, seq,
826 AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
827 break;
828 }
829 case AUDIT_TTY_SET: {
830 struct audit_tty_status s;
831 struct task_struct *tsk = current;
832
833 memset(&s, 0, sizeof(s));
834 /* guard against past and future API changes */
835 memcpy(&s, data, min(sizeof(s), (size_t)nlh->nlmsg_len));
836 if ((s.enabled != 0 && s.enabled != 1) ||
837 (s.log_passwd != 0 && s.log_passwd != 1))
838 return -EINVAL;
839
840 spin_lock(&tsk->sighand->siglock);
841 tsk->signal->audit_tty = s.enabled;
842 tsk->signal->audit_tty_log_passwd = s.log_passwd;
843 spin_unlock(&tsk->sighand->siglock);
844 break;
845 }
846 default:
847 err = -EINVAL;
848 break;
849 }
850
851 return err < 0 ? err : 0;
852}
853
854/*
855 * Get message from skb. Each message is processed by audit_receive_msg.
856 * Malformed skbs with wrong length are discarded silently.
857 */
858static void audit_receive_skb(struct sk_buff *skb)
859{
860 struct nlmsghdr *nlh;
861 /*
862 * len MUST be signed for nlmsg_next to be able to dec it below 0
863 * if the nlmsg_len was not aligned
864 */
865 int len;
866 int err;
867
868 nlh = nlmsg_hdr(skb);
869 len = skb->len;
870
871 while (nlmsg_ok(nlh, len)) {
872 err = audit_receive_msg(skb, nlh);
873 /* if err or if this message says it wants a response */
874 if (err || (nlh->nlmsg_flags & NLM_F_ACK))
875 netlink_ack(skb, nlh, err);
876
877 nlh = nlmsg_next(nlh, &len);
878 }
879}
880
881/* Receive messages from netlink socket. */
882static void audit_receive(struct sk_buff *skb)
883{
884 mutex_lock(&audit_cmd_mutex);
885 audit_receive_skb(skb);
886 mutex_unlock(&audit_cmd_mutex);
887}
888
889/* Initialize audit support at boot time. */
890static int __init audit_init(void)
891{
892 int i;
893 struct netlink_kernel_cfg cfg = {
894 .input = audit_receive,
895 };
896
897 if (audit_initialized == AUDIT_DISABLED)
898 return 0;
899
900 printk(KERN_INFO "audit: initializing netlink socket (%s)\n",
901 audit_default ? "enabled" : "disabled");
902 audit_sock = netlink_kernel_create(&init_net, NETLINK_AUDIT, &cfg);
903 if (!audit_sock)
904 audit_panic("cannot initialize netlink socket");
905 else
906 audit_sock->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
907
908 skb_queue_head_init(&audit_skb_queue);
909 skb_queue_head_init(&audit_skb_hold_queue);
910 audit_initialized = AUDIT_INITIALIZED;
911 audit_enabled = audit_default;
912 audit_ever_enabled |= !!audit_default;
913
914 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized");
915
916 for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
917 INIT_LIST_HEAD(&audit_inode_hash[i]);
918
919 return 0;
920}
921__initcall(audit_init);
922
923/* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
924static int __init audit_enable(char *str)
925{
926 audit_default = !!simple_strtol(str, NULL, 0);
927 if (!audit_default)
928 audit_initialized = AUDIT_DISABLED;
929
930 printk(KERN_INFO "audit: %s", audit_default ? "enabled" : "disabled");
931
932 if (audit_initialized == AUDIT_INITIALIZED) {
933 audit_enabled = audit_default;
934 audit_ever_enabled |= !!audit_default;
935 } else if (audit_initialized == AUDIT_UNINITIALIZED) {
936 printk(" (after initialization)");
937 } else {
938 printk(" (until reboot)");
939 }
940 printk("\n");
941
942 return 1;
943}
944
945__setup("audit=", audit_enable);
946
947static void audit_buffer_free(struct audit_buffer *ab)
948{
949 unsigned long flags;
950
951 if (!ab)
952 return;
953
954 if (ab->skb)
955 kfree_skb(ab->skb);
956
957 spin_lock_irqsave(&audit_freelist_lock, flags);
958 if (audit_freelist_count > AUDIT_MAXFREE)
959 kfree(ab);
960 else {
961 audit_freelist_count++;
962 list_add(&ab->list, &audit_freelist);
963 }
964 spin_unlock_irqrestore(&audit_freelist_lock, flags);
965}
966
967static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx,
968 gfp_t gfp_mask, int type)
969{
970 unsigned long flags;
971 struct audit_buffer *ab = NULL;
972 struct nlmsghdr *nlh;
973
974 spin_lock_irqsave(&audit_freelist_lock, flags);
975 if (!list_empty(&audit_freelist)) {
976 ab = list_entry(audit_freelist.next,
977 struct audit_buffer, list);
978 list_del(&ab->list);
979 --audit_freelist_count;
980 }
981 spin_unlock_irqrestore(&audit_freelist_lock, flags);
982
983 if (!ab) {
984 ab = kmalloc(sizeof(*ab), gfp_mask);
985 if (!ab)
986 goto err;
987 }
988
989 ab->ctx = ctx;
990 ab->gfp_mask = gfp_mask;
991
992 ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
993 if (!ab->skb)
994 goto err;
995
996 nlh = nlmsg_put(ab->skb, 0, 0, type, 0, 0);
997 if (!nlh)
998 goto out_kfree_skb;
999
1000 return ab;
1001
1002out_kfree_skb:
1003 kfree_skb(ab->skb);
1004 ab->skb = NULL;
1005err:
1006 audit_buffer_free(ab);
1007 return NULL;
1008}
1009
1010/**
1011 * audit_serial - compute a serial number for the audit record
1012 *
1013 * Compute a serial number for the audit record. Audit records are
1014 * written to user-space as soon as they are generated, so a complete
1015 * audit record may be written in several pieces. The timestamp of the
1016 * record and this serial number are used by the user-space tools to
1017 * determine which pieces belong to the same audit record. The
1018 * (timestamp,serial) tuple is unique for each syscall and is live from
1019 * syscall entry to syscall exit.
1020 *
1021 * NOTE: Another possibility is to store the formatted records off the
1022 * audit context (for those records that have a context), and emit them
1023 * all at syscall exit. However, this could delay the reporting of
1024 * significant errors until syscall exit (or never, if the system
1025 * halts).
1026 */
1027unsigned int audit_serial(void)
1028{
1029 static DEFINE_SPINLOCK(serial_lock);
1030 static unsigned int serial = 0;
1031
1032 unsigned long flags;
1033 unsigned int ret;
1034
1035 spin_lock_irqsave(&serial_lock, flags);
1036 do {
1037 ret = ++serial;
1038 } while (unlikely(!ret));
1039 spin_unlock_irqrestore(&serial_lock, flags);
1040
1041 return ret;
1042}
1043
1044static inline void audit_get_stamp(struct audit_context *ctx,
1045 struct timespec *t, unsigned int *serial)
1046{
1047 if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
1048 *t = CURRENT_TIME;
1049 *serial = audit_serial();
1050 }
1051}
1052
1053/*
1054 * Wait for auditd to drain the queue a little
1055 */
1056static void wait_for_auditd(unsigned long sleep_time)
1057{
1058 DECLARE_WAITQUEUE(wait, current);
1059 set_current_state(TASK_UNINTERRUPTIBLE);
1060 add_wait_queue(&audit_backlog_wait, &wait);
1061
1062 if (audit_backlog_limit &&
1063 skb_queue_len(&audit_skb_queue) > audit_backlog_limit)
1064 schedule_timeout(sleep_time);
1065
1066 __set_current_state(TASK_RUNNING);
1067 remove_wait_queue(&audit_backlog_wait, &wait);
1068}
1069
1070/* Obtain an audit buffer. This routine does locking to obtain the
1071 * audit buffer, but then no locking is required for calls to
1072 * audit_log_*format. If the tsk is a task that is currently in a
1073 * syscall, then the syscall is marked as auditable and an audit record
1074 * will be written at syscall exit. If there is no associated task, tsk
1075 * should be NULL. */
1076
1077/**
1078 * audit_log_start - obtain an audit buffer
1079 * @ctx: audit_context (may be NULL)
1080 * @gfp_mask: type of allocation
1081 * @type: audit message type
1082 *
1083 * Returns audit_buffer pointer on success or NULL on error.
1084 *
1085 * Obtain an audit buffer. This routine does locking to obtain the
1086 * audit buffer, but then no locking is required for calls to
1087 * audit_log_*format. If the task (ctx) is a task that is currently in a
1088 * syscall, then the syscall is marked as auditable and an audit record
1089 * will be written at syscall exit. If there is no associated task, then
1090 * task context (ctx) should be NULL.
1091 */
1092struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1093 int type)
1094{
1095 struct audit_buffer *ab = NULL;
1096 struct timespec t;
1097 unsigned int uninitialized_var(serial);
1098 int reserve;
1099 unsigned long timeout_start = jiffies;
1100
1101 if (audit_initialized != AUDIT_INITIALIZED)
1102 return NULL;
1103
1104 if (unlikely(audit_filter_type(type)))
1105 return NULL;
1106
1107 if (gfp_mask & __GFP_WAIT)
1108 reserve = 0;
1109 else
1110 reserve = 5; /* Allow atomic callers to go up to five
1111 entries over the normal backlog limit */
1112
1113 while (audit_backlog_limit
1114 && skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) {
1115 if (gfp_mask & __GFP_WAIT && audit_backlog_wait_time) {
1116 unsigned long sleep_time;
1117
1118 sleep_time = timeout_start + audit_backlog_wait_time -
1119 jiffies;
1120 if ((long)sleep_time > 0) {
1121 wait_for_auditd(sleep_time);
1122 continue;
1123 }
1124 }
1125 if (audit_rate_check() && printk_ratelimit())
1126 printk(KERN_WARNING
1127 "audit: audit_backlog=%d > "
1128 "audit_backlog_limit=%d\n",
1129 skb_queue_len(&audit_skb_queue),
1130 audit_backlog_limit);
1131 audit_log_lost("backlog limit exceeded");
1132 audit_backlog_wait_time = audit_backlog_wait_overflow;
1133 wake_up(&audit_backlog_wait);
1134 return NULL;
1135 }
1136
1137 ab = audit_buffer_alloc(ctx, gfp_mask, type);
1138 if (!ab) {
1139 audit_log_lost("out of memory in audit_log_start");
1140 return NULL;
1141 }
1142
1143 audit_get_stamp(ab->ctx, &t, &serial);
1144
1145 audit_log_format(ab, "audit(%lu.%03lu:%u): ",
1146 t.tv_sec, t.tv_nsec/1000000, serial);
1147 return ab;
1148}
1149
1150/**
1151 * audit_expand - expand skb in the audit buffer
1152 * @ab: audit_buffer
1153 * @extra: space to add at tail of the skb
1154 *
1155 * Returns 0 (no space) on failed expansion, or available space if
1156 * successful.
1157 */
1158static inline int audit_expand(struct audit_buffer *ab, int extra)
1159{
1160 struct sk_buff *skb = ab->skb;
1161 int oldtail = skb_tailroom(skb);
1162 int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1163 int newtail = skb_tailroom(skb);
1164
1165 if (ret < 0) {
1166 audit_log_lost("out of memory in audit_expand");
1167 return 0;
1168 }
1169
1170 skb->truesize += newtail - oldtail;
1171 return newtail;
1172}
1173
1174/*
1175 * Format an audit message into the audit buffer. If there isn't enough
1176 * room in the audit buffer, more room will be allocated and vsnprint
1177 * will be called a second time. Currently, we assume that a printk
1178 * can't format message larger than 1024 bytes, so we don't either.
1179 */
1180static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1181 va_list args)
1182{
1183 int len, avail;
1184 struct sk_buff *skb;
1185 va_list args2;
1186
1187 if (!ab)
1188 return;
1189
1190 BUG_ON(!ab->skb);
1191 skb = ab->skb;
1192 avail = skb_tailroom(skb);
1193 if (avail == 0) {
1194 avail = audit_expand(ab, AUDIT_BUFSIZ);
1195 if (!avail)
1196 goto out;
1197 }
1198 va_copy(args2, args);
1199 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1200 if (len >= avail) {
1201 /* The printk buffer is 1024 bytes long, so if we get
1202 * here and AUDIT_BUFSIZ is at least 1024, then we can
1203 * log everything that printk could have logged. */
1204 avail = audit_expand(ab,
1205 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1206 if (!avail)
1207 goto out_va_end;
1208 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1209 }
1210 if (len > 0)
1211 skb_put(skb, len);
1212out_va_end:
1213 va_end(args2);
1214out:
1215 return;
1216}
1217
1218/**
1219 * audit_log_format - format a message into the audit buffer.
1220 * @ab: audit_buffer
1221 * @fmt: format string
1222 * @...: optional parameters matching @fmt string
1223 *
1224 * All the work is done in audit_log_vformat.
1225 */
1226void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1227{
1228 va_list args;
1229
1230 if (!ab)
1231 return;
1232 va_start(args, fmt);
1233 audit_log_vformat(ab, fmt, args);
1234 va_end(args);
1235}
1236
1237/**
1238 * audit_log_hex - convert a buffer to hex and append it to the audit skb
1239 * @ab: the audit_buffer
1240 * @buf: buffer to convert to hex
1241 * @len: length of @buf to be converted
1242 *
1243 * No return value; failure to expand is silently ignored.
1244 *
1245 * This function will take the passed buf and convert it into a string of
1246 * ascii hex digits. The new string is placed onto the skb.
1247 */
1248void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
1249 size_t len)
1250{
1251 int i, avail, new_len;
1252 unsigned char *ptr;
1253 struct sk_buff *skb;
1254 static const unsigned char *hex = "0123456789ABCDEF";
1255
1256 if (!ab)
1257 return;
1258
1259 BUG_ON(!ab->skb);
1260 skb = ab->skb;
1261 avail = skb_tailroom(skb);
1262 new_len = len<<1;
1263 if (new_len >= avail) {
1264 /* Round the buffer request up to the next multiple */
1265 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1266 avail = audit_expand(ab, new_len);
1267 if (!avail)
1268 return;
1269 }
1270
1271 ptr = skb_tail_pointer(skb);
1272 for (i=0; i<len; i++) {
1273 *ptr++ = hex[(buf[i] & 0xF0)>>4]; /* Upper nibble */
1274 *ptr++ = hex[buf[i] & 0x0F]; /* Lower nibble */
1275 }
1276 *ptr = 0;
1277 skb_put(skb, len << 1); /* new string is twice the old string */
1278}
1279
1280/*
1281 * Format a string of no more than slen characters into the audit buffer,
1282 * enclosed in quote marks.
1283 */
1284void audit_log_n_string(struct audit_buffer *ab, const char *string,
1285 size_t slen)
1286{
1287 int avail, new_len;
1288 unsigned char *ptr;
1289 struct sk_buff *skb;
1290
1291 if (!ab)
1292 return;
1293
1294 BUG_ON(!ab->skb);
1295 skb = ab->skb;
1296 avail = skb_tailroom(skb);
1297 new_len = slen + 3; /* enclosing quotes + null terminator */
1298 if (new_len > avail) {
1299 avail = audit_expand(ab, new_len);
1300 if (!avail)
1301 return;
1302 }
1303 ptr = skb_tail_pointer(skb);
1304 *ptr++ = '"';
1305 memcpy(ptr, string, slen);
1306 ptr += slen;
1307 *ptr++ = '"';
1308 *ptr = 0;
1309 skb_put(skb, slen + 2); /* don't include null terminator */
1310}
1311
1312/**
1313 * audit_string_contains_control - does a string need to be logged in hex
1314 * @string: string to be checked
1315 * @len: max length of the string to check
1316 */
1317int audit_string_contains_control(const char *string, size_t len)
1318{
1319 const unsigned char *p;
1320 for (p = string; p < (const unsigned char *)string + len; p++) {
1321 if (*p == '"' || *p < 0x21 || *p > 0x7e)
1322 return 1;
1323 }
1324 return 0;
1325}
1326
1327/**
1328 * audit_log_n_untrustedstring - log a string that may contain random characters
1329 * @ab: audit_buffer
1330 * @len: length of string (not including trailing null)
1331 * @string: string to be logged
1332 *
1333 * This code will escape a string that is passed to it if the string
1334 * contains a control character, unprintable character, double quote mark,
1335 * or a space. Unescaped strings will start and end with a double quote mark.
1336 * Strings that are escaped are printed in hex (2 digits per char).
1337 *
1338 * The caller specifies the number of characters in the string to log, which may
1339 * or may not be the entire string.
1340 */
1341void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
1342 size_t len)
1343{
1344 if (audit_string_contains_control(string, len))
1345 audit_log_n_hex(ab, string, len);
1346 else
1347 audit_log_n_string(ab, string, len);
1348}
1349
1350/**
1351 * audit_log_untrustedstring - log a string that may contain random characters
1352 * @ab: audit_buffer
1353 * @string: string to be logged
1354 *
1355 * Same as audit_log_n_untrustedstring(), except that strlen is used to
1356 * determine string length.
1357 */
1358void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
1359{
1360 audit_log_n_untrustedstring(ab, string, strlen(string));
1361}
1362
1363/* This is a helper-function to print the escaped d_path */
1364void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
1365 const struct path *path)
1366{
1367 char *p, *pathname;
1368
1369 if (prefix)
1370 audit_log_format(ab, "%s", prefix);
1371
1372 /* We will allow 11 spaces for ' (deleted)' to be appended */
1373 pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
1374 if (!pathname) {
1375 audit_log_string(ab, "<no_memory>");
1376 return;
1377 }
1378 p = d_path(path, pathname, PATH_MAX+11);
1379 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
1380 /* FIXME: can we save some information here? */
1381 audit_log_string(ab, "<too_long>");
1382 } else
1383 audit_log_untrustedstring(ab, p);
1384 kfree(pathname);
1385}
1386
1387void audit_log_session_info(struct audit_buffer *ab)
1388{
1389 u32 sessionid = audit_get_sessionid(current);
1390 uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
1391
1392 audit_log_format(ab, " auid=%u ses=%u\n", auid, sessionid);
1393}
1394
1395void audit_log_key(struct audit_buffer *ab, char *key)
1396{
1397 audit_log_format(ab, " key=");
1398 if (key)
1399 audit_log_untrustedstring(ab, key);
1400 else
1401 audit_log_format(ab, "(null)");
1402}
1403
1404void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap)
1405{
1406 int i;
1407
1408 audit_log_format(ab, " %s=", prefix);
1409 CAP_FOR_EACH_U32(i) {
1410 audit_log_format(ab, "%08x",
1411 cap->cap[(_KERNEL_CAPABILITY_U32S-1) - i]);
1412 }
1413}
1414
1415void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
1416{
1417 kernel_cap_t *perm = &name->fcap.permitted;
1418 kernel_cap_t *inh = &name->fcap.inheritable;
1419 int log = 0;
1420
1421 if (!cap_isclear(*perm)) {
1422 audit_log_cap(ab, "cap_fp", perm);
1423 log = 1;
1424 }
1425 if (!cap_isclear(*inh)) {
1426 audit_log_cap(ab, "cap_fi", inh);
1427 log = 1;
1428 }
1429
1430 if (log)
1431 audit_log_format(ab, " cap_fe=%d cap_fver=%x",
1432 name->fcap.fE, name->fcap_ver);
1433}
1434
1435static inline int audit_copy_fcaps(struct audit_names *name,
1436 const struct dentry *dentry)
1437{
1438 struct cpu_vfs_cap_data caps;
1439 int rc;
1440
1441 if (!dentry)
1442 return 0;
1443
1444 rc = get_vfs_caps_from_disk(dentry, &caps);
1445 if (rc)
1446 return rc;
1447
1448 name->fcap.permitted = caps.permitted;
1449 name->fcap.inheritable = caps.inheritable;
1450 name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
1451 name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >>
1452 VFS_CAP_REVISION_SHIFT;
1453
1454 return 0;
1455}
1456
1457/* Copy inode data into an audit_names. */
1458void audit_copy_inode(struct audit_names *name, const struct dentry *dentry,
1459 const struct inode *inode)
1460{
1461 name->ino = inode->i_ino;
1462 name->dev = inode->i_sb->s_dev;
1463 name->mode = inode->i_mode;
1464 name->uid = inode->i_uid;
1465 name->gid = inode->i_gid;
1466 name->rdev = inode->i_rdev;
1467 security_inode_getsecid(inode, &name->osid);
1468 audit_copy_fcaps(name, dentry);
1469}
1470
1471/**
1472 * audit_log_name - produce AUDIT_PATH record from struct audit_names
1473 * @context: audit_context for the task
1474 * @n: audit_names structure with reportable details
1475 * @path: optional path to report instead of audit_names->name
1476 * @record_num: record number to report when handling a list of names
1477 * @call_panic: optional pointer to int that will be updated if secid fails
1478 */
1479void audit_log_name(struct audit_context *context, struct audit_names *n,
1480 struct path *path, int record_num, int *call_panic)
1481{
1482 struct audit_buffer *ab;
1483 ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH);
1484 if (!ab)
1485 return;
1486
1487 audit_log_format(ab, "item=%d", record_num);
1488
1489 if (path)
1490 audit_log_d_path(ab, " name=", path);
1491 else if (n->name) {
1492 switch (n->name_len) {
1493 case AUDIT_NAME_FULL:
1494 /* log the full path */
1495 audit_log_format(ab, " name=");
1496 audit_log_untrustedstring(ab, n->name->name);
1497 break;
1498 case 0:
1499 /* name was specified as a relative path and the
1500 * directory component is the cwd */
1501 audit_log_d_path(ab, " name=", &context->pwd);
1502 break;
1503 default:
1504 /* log the name's directory component */
1505 audit_log_format(ab, " name=");
1506 audit_log_n_untrustedstring(ab, n->name->name,
1507 n->name_len);
1508 }
1509 } else
1510 audit_log_format(ab, " name=(null)");
1511
1512 if (n->ino != (unsigned long)-1) {
1513 audit_log_format(ab, " inode=%lu"
1514 " dev=%02x:%02x mode=%#ho"
1515 " ouid=%u ogid=%u rdev=%02x:%02x",
1516 n->ino,
1517 MAJOR(n->dev),
1518 MINOR(n->dev),
1519 n->mode,
1520 from_kuid(&init_user_ns, n->uid),
1521 from_kgid(&init_user_ns, n->gid),
1522 MAJOR(n->rdev),
1523 MINOR(n->rdev));
1524 }
1525 if (n->osid != 0) {
1526 char *ctx = NULL;
1527 u32 len;
1528 if (security_secid_to_secctx(
1529 n->osid, &ctx, &len)) {
1530 audit_log_format(ab, " osid=%u", n->osid);
1531 if (call_panic)
1532 *call_panic = 2;
1533 } else {
1534 audit_log_format(ab, " obj=%s", ctx);
1535 security_release_secctx(ctx, len);
1536 }
1537 }
1538
1539 audit_log_fcaps(ab, n);
1540 audit_log_end(ab);
1541}
1542
1543int audit_log_task_context(struct audit_buffer *ab)
1544{
1545 char *ctx = NULL;
1546 unsigned len;
1547 int error;
1548 u32 sid;
1549
1550 security_task_getsecid(current, &sid);
1551 if (!sid)
1552 return 0;
1553
1554 error = security_secid_to_secctx(sid, &ctx, &len);
1555 if (error) {
1556 if (error != -EINVAL)
1557 goto error_path;
1558 return 0;
1559 }
1560
1561 audit_log_format(ab, " subj=%s", ctx);
1562 security_release_secctx(ctx, len);
1563 return 0;
1564
1565error_path:
1566 audit_panic("error in audit_log_task_context");
1567 return error;
1568}
1569EXPORT_SYMBOL(audit_log_task_context);
1570
1571void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
1572{
1573 const struct cred *cred;
1574 char name[sizeof(tsk->comm)];
1575 struct mm_struct *mm = tsk->mm;
1576 char *tty;
1577
1578 if (!ab)
1579 return;
1580
1581 /* tsk == current */
1582 cred = current_cred();
1583
1584 spin_lock_irq(&tsk->sighand->siglock);
1585 if (tsk->signal && tsk->signal->tty && tsk->signal->tty->name)
1586 tty = tsk->signal->tty->name;
1587 else
1588 tty = "(none)";
1589 spin_unlock_irq(&tsk->sighand->siglock);
1590
1591 audit_log_format(ab,
1592 " ppid=%ld pid=%d auid=%u uid=%u gid=%u"
1593 " euid=%u suid=%u fsuid=%u"
1594 " egid=%u sgid=%u fsgid=%u ses=%u tty=%s",
1595 sys_getppid(),
1596 tsk->pid,
1597 from_kuid(&init_user_ns, audit_get_loginuid(tsk)),
1598 from_kuid(&init_user_ns, cred->uid),
1599 from_kgid(&init_user_ns, cred->gid),
1600 from_kuid(&init_user_ns, cred->euid),
1601 from_kuid(&init_user_ns, cred->suid),
1602 from_kuid(&init_user_ns, cred->fsuid),
1603 from_kgid(&init_user_ns, cred->egid),
1604 from_kgid(&init_user_ns, cred->sgid),
1605 from_kgid(&init_user_ns, cred->fsgid),
1606 audit_get_sessionid(tsk), tty);
1607
1608 get_task_comm(name, tsk);
1609 audit_log_format(ab, " comm=");
1610 audit_log_untrustedstring(ab, name);
1611
1612 if (mm) {
1613 down_read(&mm->mmap_sem);
1614 if (mm->exe_file)
1615 audit_log_d_path(ab, " exe=", &mm->exe_file->f_path);
1616 up_read(&mm->mmap_sem);
1617 }
1618 audit_log_task_context(ab);
1619}
1620EXPORT_SYMBOL(audit_log_task_info);
1621
1622/**
1623 * audit_log_link_denied - report a link restriction denial
1624 * @operation: specific link opreation
1625 * @link: the path that triggered the restriction
1626 */
1627void audit_log_link_denied(const char *operation, struct path *link)
1628{
1629 struct audit_buffer *ab;
1630 struct audit_names *name;
1631
1632 name = kzalloc(sizeof(*name), GFP_NOFS);
1633 if (!name)
1634 return;
1635
1636 /* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */
1637 ab = audit_log_start(current->audit_context, GFP_KERNEL,
1638 AUDIT_ANOM_LINK);
1639 if (!ab)
1640 goto out;
1641 audit_log_format(ab, "op=%s", operation);
1642 audit_log_task_info(ab, current);
1643 audit_log_format(ab, " res=0");
1644 audit_log_end(ab);
1645
1646 /* Generate AUDIT_PATH record with object. */
1647 name->type = AUDIT_TYPE_NORMAL;
1648 audit_copy_inode(name, link->dentry, link->dentry->d_inode);
1649 audit_log_name(current->audit_context, name, link, 0, NULL);
1650out:
1651 kfree(name);
1652}
1653
1654/**
1655 * audit_log_end - end one audit record
1656 * @ab: the audit_buffer
1657 *
1658 * The netlink_* functions cannot be called inside an irq context, so
1659 * the audit buffer is placed on a queue and a tasklet is scheduled to
1660 * remove them from the queue outside the irq context. May be called in
1661 * any context.
1662 */
1663void audit_log_end(struct audit_buffer *ab)
1664{
1665 if (!ab)
1666 return;
1667 if (!audit_rate_check()) {
1668 audit_log_lost("rate limit exceeded");
1669 } else {
1670 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
1671 nlh->nlmsg_len = ab->skb->len - NLMSG_HDRLEN;
1672
1673 if (audit_pid) {
1674 skb_queue_tail(&audit_skb_queue, ab->skb);
1675 wake_up_interruptible(&kauditd_wait);
1676 } else {
1677 audit_printk_skb(ab->skb);
1678 }
1679 ab->skb = NULL;
1680 }
1681 audit_buffer_free(ab);
1682}
1683
1684/**
1685 * audit_log - Log an audit record
1686 * @ctx: audit context
1687 * @gfp_mask: type of allocation
1688 * @type: audit message type
1689 * @fmt: format string to use
1690 * @...: variable parameters matching the format string
1691 *
1692 * This is a convenience function that calls audit_log_start,
1693 * audit_log_vformat, and audit_log_end. It may be called
1694 * in any context.
1695 */
1696void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
1697 const char *fmt, ...)
1698{
1699 struct audit_buffer *ab;
1700 va_list args;
1701
1702 ab = audit_log_start(ctx, gfp_mask, type);
1703 if (ab) {
1704 va_start(args, fmt);
1705 audit_log_vformat(ab, fmt, args);
1706 va_end(args);
1707 audit_log_end(ab);
1708 }
1709}
1710
1711#ifdef CONFIG_SECURITY
1712/**
1713 * audit_log_secctx - Converts and logs SELinux context
1714 * @ab: audit_buffer
1715 * @secid: security number
1716 *
1717 * This is a helper function that calls security_secid_to_secctx to convert
1718 * secid to secctx and then adds the (converted) SELinux context to the audit
1719 * log by calling audit_log_format, thus also preventing leak of internal secid
1720 * to userspace. If secid cannot be converted audit_panic is called.
1721 */
1722void audit_log_secctx(struct audit_buffer *ab, u32 secid)
1723{
1724 u32 len;
1725 char *secctx;
1726
1727 if (security_secid_to_secctx(secid, &secctx, &len)) {
1728 audit_panic("Cannot convert secid to context");
1729 } else {
1730 audit_log_format(ab, " obj=%s", secctx);
1731 security_release_secctx(secctx, len);
1732 }
1733}
1734EXPORT_SYMBOL(audit_log_secctx);
1735#endif
1736
1737EXPORT_SYMBOL(audit_log_start);
1738EXPORT_SYMBOL(audit_log_end);
1739EXPORT_SYMBOL(audit_log_format);
1740EXPORT_SYMBOL(audit_log);