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1/* audit.c -- Auditing support
2 * Gateway between the kernel (e.g., selinux) and the user-space audit daemon.
3 * System-call specific features have moved to auditsc.c
4 *
5 * Copyright 2003-2007 Red Hat Inc., Durham, North Carolina.
6 * All Rights Reserved.
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 *
22 * Written by Rickard E. (Rik) Faith <faith@redhat.com>
23 *
24 * Goals: 1) Integrate fully with Security Modules.
25 * 2) Minimal run-time overhead:
26 * a) Minimal when syscall auditing is disabled (audit_enable=0).
27 * b) Small when syscall auditing is enabled and no audit record
28 * is generated (defer as much work as possible to record
29 * generation time):
30 * i) context is allocated,
31 * ii) names from getname are stored without a copy, and
32 * iii) inode information stored from path_lookup.
33 * 3) Ability to disable syscall auditing at boot time (audit=0).
34 * 4) Usable by other parts of the kernel (if audit_log* is called,
35 * then a syscall record will be generated automatically for the
36 * current syscall).
37 * 5) Netlink interface to user-space.
38 * 6) Support low-overhead kernel-based filtering to minimize the
39 * information that must be passed to user-space.
40 *
41 * Example user-space utilities: http://people.redhat.com/sgrubb/audit/
42 */
43
44#include <linux/init.h>
45#include <asm/types.h>
46#include <linux/atomic.h>
47#include <linux/mm.h>
48#include <linux/module.h>
49#include <linux/slab.h>
50#include <linux/err.h>
51#include <linux/kthread.h>
52
53#include <linux/audit.h>
54
55#include <net/sock.h>
56#include <net/netlink.h>
57#include <linux/skbuff.h>
58#ifdef CONFIG_SECURITY
59#include <linux/security.h>
60#endif
61#include <linux/netlink.h>
62#include <linux/freezer.h>
63#include <linux/tty.h>
64
65#include "audit.h"
66
67/* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
68 * (Initialization happens after skb_init is called.) */
69#define AUDIT_DISABLED -1
70#define AUDIT_UNINITIALIZED 0
71#define AUDIT_INITIALIZED 1
72static int audit_initialized;
73
74#define AUDIT_OFF 0
75#define AUDIT_ON 1
76#define AUDIT_LOCKED 2
77int audit_enabled;
78int audit_ever_enabled;
79
80EXPORT_SYMBOL_GPL(audit_enabled);
81
82/* Default state when kernel boots without any parameters. */
83static int audit_default;
84
85/* If auditing cannot proceed, audit_failure selects what happens. */
86static int audit_failure = AUDIT_FAIL_PRINTK;
87
88/*
89 * If audit records are to be written to the netlink socket, audit_pid
90 * contains the pid of the auditd process and audit_nlk_pid contains
91 * the pid to use to send netlink messages to that process.
92 */
93int audit_pid;
94static int audit_nlk_pid;
95
96/* If audit_rate_limit is non-zero, limit the rate of sending audit records
97 * to that number per second. This prevents DoS attacks, but results in
98 * audit records being dropped. */
99static int audit_rate_limit;
100
101/* Number of outstanding audit_buffers allowed. */
102static int audit_backlog_limit = 64;
103static int audit_backlog_wait_time = 60 * HZ;
104static int audit_backlog_wait_overflow = 0;
105
106/* The identity of the user shutting down the audit system. */
107uid_t audit_sig_uid = -1;
108pid_t audit_sig_pid = -1;
109u32 audit_sig_sid = 0;
110
111/* Records can be lost in several ways:
112 0) [suppressed in audit_alloc]
113 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
114 2) out of memory in audit_log_move [alloc_skb]
115 3) suppressed due to audit_rate_limit
116 4) suppressed due to audit_backlog_limit
117*/
118static atomic_t audit_lost = ATOMIC_INIT(0);
119
120/* The netlink socket. */
121static struct sock *audit_sock;
122
123/* Hash for inode-based rules */
124struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
125
126/* The audit_freelist is a list of pre-allocated audit buffers (if more
127 * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
128 * being placed on the freelist). */
129static DEFINE_SPINLOCK(audit_freelist_lock);
130static int audit_freelist_count;
131static LIST_HEAD(audit_freelist);
132
133static struct sk_buff_head audit_skb_queue;
134/* queue of skbs to send to auditd when/if it comes back */
135static struct sk_buff_head audit_skb_hold_queue;
136static struct task_struct *kauditd_task;
137static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
138static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
139
140/* Serialize requests from userspace. */
141DEFINE_MUTEX(audit_cmd_mutex);
142
143/* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
144 * audit records. Since printk uses a 1024 byte buffer, this buffer
145 * should be at least that large. */
146#define AUDIT_BUFSIZ 1024
147
148/* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the
149 * audit_freelist. Doing so eliminates many kmalloc/kfree calls. */
150#define AUDIT_MAXFREE (2*NR_CPUS)
151
152/* The audit_buffer is used when formatting an audit record. The caller
153 * locks briefly to get the record off the freelist or to allocate the
154 * buffer, and locks briefly to send the buffer to the netlink layer or
155 * to place it on a transmit queue. Multiple audit_buffers can be in
156 * use simultaneously. */
157struct audit_buffer {
158 struct list_head list;
159 struct sk_buff *skb; /* formatted skb ready to send */
160 struct audit_context *ctx; /* NULL or associated context */
161 gfp_t gfp_mask;
162};
163
164struct audit_reply {
165 int pid;
166 struct sk_buff *skb;
167};
168
169static void audit_set_pid(struct audit_buffer *ab, pid_t pid)
170{
171 if (ab) {
172 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
173 nlh->nlmsg_pid = pid;
174 }
175}
176
177void audit_panic(const char *message)
178{
179 switch (audit_failure)
180 {
181 case AUDIT_FAIL_SILENT:
182 break;
183 case AUDIT_FAIL_PRINTK:
184 if (printk_ratelimit())
185 printk(KERN_ERR "audit: %s\n", message);
186 break;
187 case AUDIT_FAIL_PANIC:
188 /* test audit_pid since printk is always losey, why bother? */
189 if (audit_pid)
190 panic("audit: %s\n", message);
191 break;
192 }
193}
194
195static inline int audit_rate_check(void)
196{
197 static unsigned long last_check = 0;
198 static int messages = 0;
199 static DEFINE_SPINLOCK(lock);
200 unsigned long flags;
201 unsigned long now;
202 unsigned long elapsed;
203 int retval = 0;
204
205 if (!audit_rate_limit) return 1;
206
207 spin_lock_irqsave(&lock, flags);
208 if (++messages < audit_rate_limit) {
209 retval = 1;
210 } else {
211 now = jiffies;
212 elapsed = now - last_check;
213 if (elapsed > HZ) {
214 last_check = now;
215 messages = 0;
216 retval = 1;
217 }
218 }
219 spin_unlock_irqrestore(&lock, flags);
220
221 return retval;
222}
223
224/**
225 * audit_log_lost - conditionally log lost audit message event
226 * @message: the message stating reason for lost audit message
227 *
228 * Emit at least 1 message per second, even if audit_rate_check is
229 * throttling.
230 * Always increment the lost messages counter.
231*/
232void audit_log_lost(const char *message)
233{
234 static unsigned long last_msg = 0;
235 static DEFINE_SPINLOCK(lock);
236 unsigned long flags;
237 unsigned long now;
238 int print;
239
240 atomic_inc(&audit_lost);
241
242 print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
243
244 if (!print) {
245 spin_lock_irqsave(&lock, flags);
246 now = jiffies;
247 if (now - last_msg > HZ) {
248 print = 1;
249 last_msg = now;
250 }
251 spin_unlock_irqrestore(&lock, flags);
252 }
253
254 if (print) {
255 if (printk_ratelimit())
256 printk(KERN_WARNING
257 "audit: audit_lost=%d audit_rate_limit=%d "
258 "audit_backlog_limit=%d\n",
259 atomic_read(&audit_lost),
260 audit_rate_limit,
261 audit_backlog_limit);
262 audit_panic(message);
263 }
264}
265
266static int audit_log_config_change(char *function_name, int new, int old,
267 uid_t loginuid, u32 sessionid, u32 sid,
268 int allow_changes)
269{
270 struct audit_buffer *ab;
271 int rc = 0;
272
273 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
274 audit_log_format(ab, "%s=%d old=%d auid=%u ses=%u", function_name, new,
275 old, loginuid, sessionid);
276 if (sid) {
277 char *ctx = NULL;
278 u32 len;
279
280 rc = security_secid_to_secctx(sid, &ctx, &len);
281 if (rc) {
282 audit_log_format(ab, " sid=%u", sid);
283 allow_changes = 0; /* Something weird, deny request */
284 } else {
285 audit_log_format(ab, " subj=%s", ctx);
286 security_release_secctx(ctx, len);
287 }
288 }
289 audit_log_format(ab, " res=%d", allow_changes);
290 audit_log_end(ab);
291 return rc;
292}
293
294static int audit_do_config_change(char *function_name, int *to_change,
295 int new, uid_t loginuid, u32 sessionid,
296 u32 sid)
297{
298 int allow_changes, rc = 0, old = *to_change;
299
300 /* check if we are locked */
301 if (audit_enabled == AUDIT_LOCKED)
302 allow_changes = 0;
303 else
304 allow_changes = 1;
305
306 if (audit_enabled != AUDIT_OFF) {
307 rc = audit_log_config_change(function_name, new, old, loginuid,
308 sessionid, sid, allow_changes);
309 if (rc)
310 allow_changes = 0;
311 }
312
313 /* If we are allowed, make the change */
314 if (allow_changes == 1)
315 *to_change = new;
316 /* Not allowed, update reason */
317 else if (rc == 0)
318 rc = -EPERM;
319 return rc;
320}
321
322static int audit_set_rate_limit(int limit, uid_t loginuid, u32 sessionid,
323 u32 sid)
324{
325 return audit_do_config_change("audit_rate_limit", &audit_rate_limit,
326 limit, loginuid, sessionid, sid);
327}
328
329static int audit_set_backlog_limit(int limit, uid_t loginuid, u32 sessionid,
330 u32 sid)
331{
332 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit,
333 limit, loginuid, sessionid, sid);
334}
335
336static int audit_set_enabled(int state, uid_t loginuid, u32 sessionid, u32 sid)
337{
338 int rc;
339 if (state < AUDIT_OFF || state > AUDIT_LOCKED)
340 return -EINVAL;
341
342 rc = audit_do_config_change("audit_enabled", &audit_enabled, state,
343 loginuid, sessionid, sid);
344
345 if (!rc)
346 audit_ever_enabled |= !!state;
347
348 return rc;
349}
350
351static int audit_set_failure(int state, uid_t loginuid, u32 sessionid, u32 sid)
352{
353 if (state != AUDIT_FAIL_SILENT
354 && state != AUDIT_FAIL_PRINTK
355 && state != AUDIT_FAIL_PANIC)
356 return -EINVAL;
357
358 return audit_do_config_change("audit_failure", &audit_failure, state,
359 loginuid, sessionid, sid);
360}
361
362/*
363 * Queue skbs to be sent to auditd when/if it comes back. These skbs should
364 * already have been sent via prink/syslog and so if these messages are dropped
365 * it is not a huge concern since we already passed the audit_log_lost()
366 * notification and stuff. This is just nice to get audit messages during
367 * boot before auditd is running or messages generated while auditd is stopped.
368 * This only holds messages is audit_default is set, aka booting with audit=1
369 * or building your kernel that way.
370 */
371static void audit_hold_skb(struct sk_buff *skb)
372{
373 if (audit_default &&
374 skb_queue_len(&audit_skb_hold_queue) < audit_backlog_limit)
375 skb_queue_tail(&audit_skb_hold_queue, skb);
376 else
377 kfree_skb(skb);
378}
379
380/*
381 * For one reason or another this nlh isn't getting delivered to the userspace
382 * audit daemon, just send it to printk.
383 */
384static void audit_printk_skb(struct sk_buff *skb)
385{
386 struct nlmsghdr *nlh = nlmsg_hdr(skb);
387 char *data = NLMSG_DATA(nlh);
388
389 if (nlh->nlmsg_type != AUDIT_EOE) {
390 if (printk_ratelimit())
391 printk(KERN_NOTICE "type=%d %s\n", nlh->nlmsg_type, data);
392 else
393 audit_log_lost("printk limit exceeded\n");
394 }
395
396 audit_hold_skb(skb);
397}
398
399static void kauditd_send_skb(struct sk_buff *skb)
400{
401 int err;
402 /* take a reference in case we can't send it and we want to hold it */
403 skb_get(skb);
404 err = netlink_unicast(audit_sock, skb, audit_nlk_pid, 0);
405 if (err < 0) {
406 BUG_ON(err != -ECONNREFUSED); /* Shouldn't happen */
407 printk(KERN_ERR "audit: *NO* daemon at audit_pid=%d\n", audit_pid);
408 audit_log_lost("auditd disappeared\n");
409 audit_pid = 0;
410 /* we might get lucky and get this in the next auditd */
411 audit_hold_skb(skb);
412 } else
413 /* drop the extra reference if sent ok */
414 consume_skb(skb);
415}
416
417static int kauditd_thread(void *dummy)
418{
419 struct sk_buff *skb;
420
421 set_freezable();
422 while (!kthread_should_stop()) {
423 /*
424 * if auditd just started drain the queue of messages already
425 * sent to syslog/printk. remember loss here is ok. we already
426 * called audit_log_lost() if it didn't go out normally. so the
427 * race between the skb_dequeue and the next check for audit_pid
428 * doesn't matter.
429 *
430 * if you ever find kauditd to be too slow we can get a perf win
431 * by doing our own locking and keeping better track if there
432 * are messages in this queue. I don't see the need now, but
433 * in 5 years when I want to play with this again I'll see this
434 * note and still have no friggin idea what i'm thinking today.
435 */
436 if (audit_default && audit_pid) {
437 skb = skb_dequeue(&audit_skb_hold_queue);
438 if (unlikely(skb)) {
439 while (skb && audit_pid) {
440 kauditd_send_skb(skb);
441 skb = skb_dequeue(&audit_skb_hold_queue);
442 }
443 }
444 }
445
446 skb = skb_dequeue(&audit_skb_queue);
447 wake_up(&audit_backlog_wait);
448 if (skb) {
449 if (audit_pid)
450 kauditd_send_skb(skb);
451 else
452 audit_printk_skb(skb);
453 } else {
454 DECLARE_WAITQUEUE(wait, current);
455 set_current_state(TASK_INTERRUPTIBLE);
456 add_wait_queue(&kauditd_wait, &wait);
457
458 if (!skb_queue_len(&audit_skb_queue)) {
459 try_to_freeze();
460 schedule();
461 }
462
463 __set_current_state(TASK_RUNNING);
464 remove_wait_queue(&kauditd_wait, &wait);
465 }
466 }
467 return 0;
468}
469
470static int audit_prepare_user_tty(pid_t pid, uid_t loginuid, u32 sessionid)
471{
472 struct task_struct *tsk;
473 int err;
474
475 rcu_read_lock();
476 tsk = find_task_by_vpid(pid);
477 if (!tsk) {
478 rcu_read_unlock();
479 return -ESRCH;
480 }
481 get_task_struct(tsk);
482 rcu_read_unlock();
483 err = tty_audit_push_task(tsk, loginuid, sessionid);
484 put_task_struct(tsk);
485 return err;
486}
487
488int audit_send_list(void *_dest)
489{
490 struct audit_netlink_list *dest = _dest;
491 int pid = dest->pid;
492 struct sk_buff *skb;
493
494 /* wait for parent to finish and send an ACK */
495 mutex_lock(&audit_cmd_mutex);
496 mutex_unlock(&audit_cmd_mutex);
497
498 while ((skb = __skb_dequeue(&dest->q)) != NULL)
499 netlink_unicast(audit_sock, skb, pid, 0);
500
501 kfree(dest);
502
503 return 0;
504}
505
506struct sk_buff *audit_make_reply(int pid, int seq, int type, int done,
507 int multi, const void *payload, int size)
508{
509 struct sk_buff *skb;
510 struct nlmsghdr *nlh;
511 void *data;
512 int flags = multi ? NLM_F_MULTI : 0;
513 int t = done ? NLMSG_DONE : type;
514
515 skb = nlmsg_new(size, GFP_KERNEL);
516 if (!skb)
517 return NULL;
518
519 nlh = NLMSG_NEW(skb, pid, seq, t, size, flags);
520 data = NLMSG_DATA(nlh);
521 memcpy(data, payload, size);
522 return skb;
523
524nlmsg_failure: /* Used by NLMSG_NEW */
525 if (skb)
526 kfree_skb(skb);
527 return NULL;
528}
529
530static int audit_send_reply_thread(void *arg)
531{
532 struct audit_reply *reply = (struct audit_reply *)arg;
533
534 mutex_lock(&audit_cmd_mutex);
535 mutex_unlock(&audit_cmd_mutex);
536
537 /* Ignore failure. It'll only happen if the sender goes away,
538 because our timeout is set to infinite. */
539 netlink_unicast(audit_sock, reply->skb, reply->pid, 0);
540 kfree(reply);
541 return 0;
542}
543/**
544 * audit_send_reply - send an audit reply message via netlink
545 * @pid: process id to send reply to
546 * @seq: sequence number
547 * @type: audit message type
548 * @done: done (last) flag
549 * @multi: multi-part message flag
550 * @payload: payload data
551 * @size: payload size
552 *
553 * Allocates an skb, builds the netlink message, and sends it to the pid.
554 * No failure notifications.
555 */
556static void audit_send_reply(int pid, int seq, int type, int done, int multi,
557 const void *payload, int size)
558{
559 struct sk_buff *skb;
560 struct task_struct *tsk;
561 struct audit_reply *reply = kmalloc(sizeof(struct audit_reply),
562 GFP_KERNEL);
563
564 if (!reply)
565 return;
566
567 skb = audit_make_reply(pid, seq, type, done, multi, payload, size);
568 if (!skb)
569 goto out;
570
571 reply->pid = pid;
572 reply->skb = skb;
573
574 tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
575 if (!IS_ERR(tsk))
576 return;
577 kfree_skb(skb);
578out:
579 kfree(reply);
580}
581
582/*
583 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
584 * control messages.
585 */
586static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
587{
588 int err = 0;
589
590 switch (msg_type) {
591 case AUDIT_GET:
592 case AUDIT_LIST:
593 case AUDIT_LIST_RULES:
594 case AUDIT_SET:
595 case AUDIT_ADD:
596 case AUDIT_ADD_RULE:
597 case AUDIT_DEL:
598 case AUDIT_DEL_RULE:
599 case AUDIT_SIGNAL_INFO:
600 case AUDIT_TTY_GET:
601 case AUDIT_TTY_SET:
602 case AUDIT_TRIM:
603 case AUDIT_MAKE_EQUIV:
604 if (security_netlink_recv(skb, CAP_AUDIT_CONTROL))
605 err = -EPERM;
606 break;
607 case AUDIT_USER:
608 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
609 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
610 if (security_netlink_recv(skb, CAP_AUDIT_WRITE))
611 err = -EPERM;
612 break;
613 default: /* bad msg */
614 err = -EINVAL;
615 }
616
617 return err;
618}
619
620static int audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type,
621 u32 pid, u32 uid, uid_t auid, u32 ses,
622 u32 sid)
623{
624 int rc = 0;
625 char *ctx = NULL;
626 u32 len;
627
628 if (!audit_enabled) {
629 *ab = NULL;
630 return rc;
631 }
632
633 *ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
634 audit_log_format(*ab, "user pid=%d uid=%u auid=%u ses=%u",
635 pid, uid, auid, ses);
636 if (sid) {
637 rc = security_secid_to_secctx(sid, &ctx, &len);
638 if (rc)
639 audit_log_format(*ab, " ssid=%u", sid);
640 else {
641 audit_log_format(*ab, " subj=%s", ctx);
642 security_release_secctx(ctx, len);
643 }
644 }
645
646 return rc;
647}
648
649static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
650{
651 u32 uid, pid, seq, sid;
652 void *data;
653 struct audit_status *status_get, status_set;
654 int err;
655 struct audit_buffer *ab;
656 u16 msg_type = nlh->nlmsg_type;
657 uid_t loginuid; /* loginuid of sender */
658 u32 sessionid;
659 struct audit_sig_info *sig_data;
660 char *ctx = NULL;
661 u32 len;
662
663 err = audit_netlink_ok(skb, msg_type);
664 if (err)
665 return err;
666
667 /* As soon as there's any sign of userspace auditd,
668 * start kauditd to talk to it */
669 if (!kauditd_task)
670 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
671 if (IS_ERR(kauditd_task)) {
672 err = PTR_ERR(kauditd_task);
673 kauditd_task = NULL;
674 return err;
675 }
676
677 pid = NETLINK_CREDS(skb)->pid;
678 uid = NETLINK_CREDS(skb)->uid;
679 loginuid = audit_get_loginuid(current);
680 sessionid = audit_get_sessionid(current);
681 security_task_getsecid(current, &sid);
682 seq = nlh->nlmsg_seq;
683 data = NLMSG_DATA(nlh);
684
685 switch (msg_type) {
686 case AUDIT_GET:
687 status_set.enabled = audit_enabled;
688 status_set.failure = audit_failure;
689 status_set.pid = audit_pid;
690 status_set.rate_limit = audit_rate_limit;
691 status_set.backlog_limit = audit_backlog_limit;
692 status_set.lost = atomic_read(&audit_lost);
693 status_set.backlog = skb_queue_len(&audit_skb_queue);
694 audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_GET, 0, 0,
695 &status_set, sizeof(status_set));
696 break;
697 case AUDIT_SET:
698 if (nlh->nlmsg_len < sizeof(struct audit_status))
699 return -EINVAL;
700 status_get = (struct audit_status *)data;
701 if (status_get->mask & AUDIT_STATUS_ENABLED) {
702 err = audit_set_enabled(status_get->enabled,
703 loginuid, sessionid, sid);
704 if (err < 0)
705 return err;
706 }
707 if (status_get->mask & AUDIT_STATUS_FAILURE) {
708 err = audit_set_failure(status_get->failure,
709 loginuid, sessionid, sid);
710 if (err < 0)
711 return err;
712 }
713 if (status_get->mask & AUDIT_STATUS_PID) {
714 int new_pid = status_get->pid;
715
716 if (audit_enabled != AUDIT_OFF)
717 audit_log_config_change("audit_pid", new_pid,
718 audit_pid, loginuid,
719 sessionid, sid, 1);
720
721 audit_pid = new_pid;
722 audit_nlk_pid = NETLINK_CB(skb).pid;
723 }
724 if (status_get->mask & AUDIT_STATUS_RATE_LIMIT) {
725 err = audit_set_rate_limit(status_get->rate_limit,
726 loginuid, sessionid, sid);
727 if (err < 0)
728 return err;
729 }
730 if (status_get->mask & AUDIT_STATUS_BACKLOG_LIMIT)
731 err = audit_set_backlog_limit(status_get->backlog_limit,
732 loginuid, sessionid, sid);
733 break;
734 case AUDIT_USER:
735 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
736 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
737 if (!audit_enabled && msg_type != AUDIT_USER_AVC)
738 return 0;
739
740 err = audit_filter_user(&NETLINK_CB(skb));
741 if (err == 1) {
742 err = 0;
743 if (msg_type == AUDIT_USER_TTY) {
744 err = audit_prepare_user_tty(pid, loginuid,
745 sessionid);
746 if (err)
747 break;
748 }
749 audit_log_common_recv_msg(&ab, msg_type, pid, uid,
750 loginuid, sessionid, sid);
751
752 if (msg_type != AUDIT_USER_TTY)
753 audit_log_format(ab, " msg='%.1024s'",
754 (char *)data);
755 else {
756 int size;
757
758 audit_log_format(ab, " msg=");
759 size = nlmsg_len(nlh);
760 if (size > 0 &&
761 ((unsigned char *)data)[size - 1] == '\0')
762 size--;
763 audit_log_n_untrustedstring(ab, data, size);
764 }
765 audit_set_pid(ab, pid);
766 audit_log_end(ab);
767 }
768 break;
769 case AUDIT_ADD:
770 case AUDIT_DEL:
771 if (nlmsg_len(nlh) < sizeof(struct audit_rule))
772 return -EINVAL;
773 if (audit_enabled == AUDIT_LOCKED) {
774 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
775 uid, loginuid, sessionid, sid);
776
777 audit_log_format(ab, " audit_enabled=%d res=0",
778 audit_enabled);
779 audit_log_end(ab);
780 return -EPERM;
781 }
782 /* fallthrough */
783 case AUDIT_LIST:
784 err = audit_receive_filter(msg_type, NETLINK_CB(skb).pid,
785 uid, seq, data, nlmsg_len(nlh),
786 loginuid, sessionid, sid);
787 break;
788 case AUDIT_ADD_RULE:
789 case AUDIT_DEL_RULE:
790 if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
791 return -EINVAL;
792 if (audit_enabled == AUDIT_LOCKED) {
793 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
794 uid, loginuid, sessionid, sid);
795
796 audit_log_format(ab, " audit_enabled=%d res=0",
797 audit_enabled);
798 audit_log_end(ab);
799 return -EPERM;
800 }
801 /* fallthrough */
802 case AUDIT_LIST_RULES:
803 err = audit_receive_filter(msg_type, NETLINK_CB(skb).pid,
804 uid, seq, data, nlmsg_len(nlh),
805 loginuid, sessionid, sid);
806 break;
807 case AUDIT_TRIM:
808 audit_trim_trees();
809
810 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
811 uid, loginuid, sessionid, sid);
812
813 audit_log_format(ab, " op=trim res=1");
814 audit_log_end(ab);
815 break;
816 case AUDIT_MAKE_EQUIV: {
817 void *bufp = data;
818 u32 sizes[2];
819 size_t msglen = nlmsg_len(nlh);
820 char *old, *new;
821
822 err = -EINVAL;
823 if (msglen < 2 * sizeof(u32))
824 break;
825 memcpy(sizes, bufp, 2 * sizeof(u32));
826 bufp += 2 * sizeof(u32);
827 msglen -= 2 * sizeof(u32);
828 old = audit_unpack_string(&bufp, &msglen, sizes[0]);
829 if (IS_ERR(old)) {
830 err = PTR_ERR(old);
831 break;
832 }
833 new = audit_unpack_string(&bufp, &msglen, sizes[1]);
834 if (IS_ERR(new)) {
835 err = PTR_ERR(new);
836 kfree(old);
837 break;
838 }
839 /* OK, here comes... */
840 err = audit_tag_tree(old, new);
841
842 audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
843 uid, loginuid, sessionid, sid);
844
845 audit_log_format(ab, " op=make_equiv old=");
846 audit_log_untrustedstring(ab, old);
847 audit_log_format(ab, " new=");
848 audit_log_untrustedstring(ab, new);
849 audit_log_format(ab, " res=%d", !err);
850 audit_log_end(ab);
851 kfree(old);
852 kfree(new);
853 break;
854 }
855 case AUDIT_SIGNAL_INFO:
856 len = 0;
857 if (audit_sig_sid) {
858 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
859 if (err)
860 return err;
861 }
862 sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
863 if (!sig_data) {
864 if (audit_sig_sid)
865 security_release_secctx(ctx, len);
866 return -ENOMEM;
867 }
868 sig_data->uid = audit_sig_uid;
869 sig_data->pid = audit_sig_pid;
870 if (audit_sig_sid) {
871 memcpy(sig_data->ctx, ctx, len);
872 security_release_secctx(ctx, len);
873 }
874 audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_SIGNAL_INFO,
875 0, 0, sig_data, sizeof(*sig_data) + len);
876 kfree(sig_data);
877 break;
878 case AUDIT_TTY_GET: {
879 struct audit_tty_status s;
880 struct task_struct *tsk;
881 unsigned long flags;
882
883 rcu_read_lock();
884 tsk = find_task_by_vpid(pid);
885 if (tsk && lock_task_sighand(tsk, &flags)) {
886 s.enabled = tsk->signal->audit_tty != 0;
887 unlock_task_sighand(tsk, &flags);
888 } else
889 err = -ESRCH;
890 rcu_read_unlock();
891
892 if (!err)
893 audit_send_reply(NETLINK_CB(skb).pid, seq,
894 AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
895 break;
896 }
897 case AUDIT_TTY_SET: {
898 struct audit_tty_status *s;
899 struct task_struct *tsk;
900 unsigned long flags;
901
902 if (nlh->nlmsg_len < sizeof(struct audit_tty_status))
903 return -EINVAL;
904 s = data;
905 if (s->enabled != 0 && s->enabled != 1)
906 return -EINVAL;
907 rcu_read_lock();
908 tsk = find_task_by_vpid(pid);
909 if (tsk && lock_task_sighand(tsk, &flags)) {
910 tsk->signal->audit_tty = s->enabled != 0;
911 unlock_task_sighand(tsk, &flags);
912 } else
913 err = -ESRCH;
914 rcu_read_unlock();
915 break;
916 }
917 default:
918 err = -EINVAL;
919 break;
920 }
921
922 return err < 0 ? err : 0;
923}
924
925/*
926 * Get message from skb. Each message is processed by audit_receive_msg.
927 * Malformed skbs with wrong length are discarded silently.
928 */
929static void audit_receive_skb(struct sk_buff *skb)
930{
931 struct nlmsghdr *nlh;
932 /*
933 * len MUST be signed for NLMSG_NEXT to be able to dec it below 0
934 * if the nlmsg_len was not aligned
935 */
936 int len;
937 int err;
938
939 nlh = nlmsg_hdr(skb);
940 len = skb->len;
941
942 while (NLMSG_OK(nlh, len)) {
943 err = audit_receive_msg(skb, nlh);
944 /* if err or if this message says it wants a response */
945 if (err || (nlh->nlmsg_flags & NLM_F_ACK))
946 netlink_ack(skb, nlh, err);
947
948 nlh = NLMSG_NEXT(nlh, len);
949 }
950}
951
952/* Receive messages from netlink socket. */
953static void audit_receive(struct sk_buff *skb)
954{
955 mutex_lock(&audit_cmd_mutex);
956 audit_receive_skb(skb);
957 mutex_unlock(&audit_cmd_mutex);
958}
959
960/* Initialize audit support at boot time. */
961static int __init audit_init(void)
962{
963 int i;
964
965 if (audit_initialized == AUDIT_DISABLED)
966 return 0;
967
968 printk(KERN_INFO "audit: initializing netlink socket (%s)\n",
969 audit_default ? "enabled" : "disabled");
970 audit_sock = netlink_kernel_create(&init_net, NETLINK_AUDIT, 0,
971 audit_receive, NULL, THIS_MODULE);
972 if (!audit_sock)
973 audit_panic("cannot initialize netlink socket");
974 else
975 audit_sock->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
976
977 skb_queue_head_init(&audit_skb_queue);
978 skb_queue_head_init(&audit_skb_hold_queue);
979 audit_initialized = AUDIT_INITIALIZED;
980 audit_enabled = audit_default;
981 audit_ever_enabled |= !!audit_default;
982
983 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized");
984
985 for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
986 INIT_LIST_HEAD(&audit_inode_hash[i]);
987
988 return 0;
989}
990__initcall(audit_init);
991
992/* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
993static int __init audit_enable(char *str)
994{
995 audit_default = !!simple_strtol(str, NULL, 0);
996 if (!audit_default)
997 audit_initialized = AUDIT_DISABLED;
998
999 printk(KERN_INFO "audit: %s", audit_default ? "enabled" : "disabled");
1000
1001 if (audit_initialized == AUDIT_INITIALIZED) {
1002 audit_enabled = audit_default;
1003 audit_ever_enabled |= !!audit_default;
1004 } else if (audit_initialized == AUDIT_UNINITIALIZED) {
1005 printk(" (after initialization)");
1006 } else {
1007 printk(" (until reboot)");
1008 }
1009 printk("\n");
1010
1011 return 1;
1012}
1013
1014__setup("audit=", audit_enable);
1015
1016static void audit_buffer_free(struct audit_buffer *ab)
1017{
1018 unsigned long flags;
1019
1020 if (!ab)
1021 return;
1022
1023 if (ab->skb)
1024 kfree_skb(ab->skb);
1025
1026 spin_lock_irqsave(&audit_freelist_lock, flags);
1027 if (audit_freelist_count > AUDIT_MAXFREE)
1028 kfree(ab);
1029 else {
1030 audit_freelist_count++;
1031 list_add(&ab->list, &audit_freelist);
1032 }
1033 spin_unlock_irqrestore(&audit_freelist_lock, flags);
1034}
1035
1036static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx,
1037 gfp_t gfp_mask, int type)
1038{
1039 unsigned long flags;
1040 struct audit_buffer *ab = NULL;
1041 struct nlmsghdr *nlh;
1042
1043 spin_lock_irqsave(&audit_freelist_lock, flags);
1044 if (!list_empty(&audit_freelist)) {
1045 ab = list_entry(audit_freelist.next,
1046 struct audit_buffer, list);
1047 list_del(&ab->list);
1048 --audit_freelist_count;
1049 }
1050 spin_unlock_irqrestore(&audit_freelist_lock, flags);
1051
1052 if (!ab) {
1053 ab = kmalloc(sizeof(*ab), gfp_mask);
1054 if (!ab)
1055 goto err;
1056 }
1057
1058 ab->ctx = ctx;
1059 ab->gfp_mask = gfp_mask;
1060
1061 ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
1062 if (!ab->skb)
1063 goto nlmsg_failure;
1064
1065 nlh = NLMSG_NEW(ab->skb, 0, 0, type, 0, 0);
1066
1067 return ab;
1068
1069nlmsg_failure: /* Used by NLMSG_NEW */
1070 kfree_skb(ab->skb);
1071 ab->skb = NULL;
1072err:
1073 audit_buffer_free(ab);
1074 return NULL;
1075}
1076
1077/**
1078 * audit_serial - compute a serial number for the audit record
1079 *
1080 * Compute a serial number for the audit record. Audit records are
1081 * written to user-space as soon as they are generated, so a complete
1082 * audit record may be written in several pieces. The timestamp of the
1083 * record and this serial number are used by the user-space tools to
1084 * determine which pieces belong to the same audit record. The
1085 * (timestamp,serial) tuple is unique for each syscall and is live from
1086 * syscall entry to syscall exit.
1087 *
1088 * NOTE: Another possibility is to store the formatted records off the
1089 * audit context (for those records that have a context), and emit them
1090 * all at syscall exit. However, this could delay the reporting of
1091 * significant errors until syscall exit (or never, if the system
1092 * halts).
1093 */
1094unsigned int audit_serial(void)
1095{
1096 static DEFINE_SPINLOCK(serial_lock);
1097 static unsigned int serial = 0;
1098
1099 unsigned long flags;
1100 unsigned int ret;
1101
1102 spin_lock_irqsave(&serial_lock, flags);
1103 do {
1104 ret = ++serial;
1105 } while (unlikely(!ret));
1106 spin_unlock_irqrestore(&serial_lock, flags);
1107
1108 return ret;
1109}
1110
1111static inline void audit_get_stamp(struct audit_context *ctx,
1112 struct timespec *t, unsigned int *serial)
1113{
1114 if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
1115 *t = CURRENT_TIME;
1116 *serial = audit_serial();
1117 }
1118}
1119
1120/* Obtain an audit buffer. This routine does locking to obtain the
1121 * audit buffer, but then no locking is required for calls to
1122 * audit_log_*format. If the tsk is a task that is currently in a
1123 * syscall, then the syscall is marked as auditable and an audit record
1124 * will be written at syscall exit. If there is no associated task, tsk
1125 * should be NULL. */
1126
1127/**
1128 * audit_log_start - obtain an audit buffer
1129 * @ctx: audit_context (may be NULL)
1130 * @gfp_mask: type of allocation
1131 * @type: audit message type
1132 *
1133 * Returns audit_buffer pointer on success or NULL on error.
1134 *
1135 * Obtain an audit buffer. This routine does locking to obtain the
1136 * audit buffer, but then no locking is required for calls to
1137 * audit_log_*format. If the task (ctx) is a task that is currently in a
1138 * syscall, then the syscall is marked as auditable and an audit record
1139 * will be written at syscall exit. If there is no associated task, then
1140 * task context (ctx) should be NULL.
1141 */
1142struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1143 int type)
1144{
1145 struct audit_buffer *ab = NULL;
1146 struct timespec t;
1147 unsigned int uninitialized_var(serial);
1148 int reserve;
1149 unsigned long timeout_start = jiffies;
1150
1151 if (audit_initialized != AUDIT_INITIALIZED)
1152 return NULL;
1153
1154 if (unlikely(audit_filter_type(type)))
1155 return NULL;
1156
1157 if (gfp_mask & __GFP_WAIT)
1158 reserve = 0;
1159 else
1160 reserve = 5; /* Allow atomic callers to go up to five
1161 entries over the normal backlog limit */
1162
1163 while (audit_backlog_limit
1164 && skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) {
1165 if (gfp_mask & __GFP_WAIT && audit_backlog_wait_time
1166 && time_before(jiffies, timeout_start + audit_backlog_wait_time)) {
1167
1168 /* Wait for auditd to drain the queue a little */
1169 DECLARE_WAITQUEUE(wait, current);
1170 set_current_state(TASK_INTERRUPTIBLE);
1171 add_wait_queue(&audit_backlog_wait, &wait);
1172
1173 if (audit_backlog_limit &&
1174 skb_queue_len(&audit_skb_queue) > audit_backlog_limit)
1175 schedule_timeout(timeout_start + audit_backlog_wait_time - jiffies);
1176
1177 __set_current_state(TASK_RUNNING);
1178 remove_wait_queue(&audit_backlog_wait, &wait);
1179 continue;
1180 }
1181 if (audit_rate_check() && printk_ratelimit())
1182 printk(KERN_WARNING
1183 "audit: audit_backlog=%d > "
1184 "audit_backlog_limit=%d\n",
1185 skb_queue_len(&audit_skb_queue),
1186 audit_backlog_limit);
1187 audit_log_lost("backlog limit exceeded");
1188 audit_backlog_wait_time = audit_backlog_wait_overflow;
1189 wake_up(&audit_backlog_wait);
1190 return NULL;
1191 }
1192
1193 ab = audit_buffer_alloc(ctx, gfp_mask, type);
1194 if (!ab) {
1195 audit_log_lost("out of memory in audit_log_start");
1196 return NULL;
1197 }
1198
1199 audit_get_stamp(ab->ctx, &t, &serial);
1200
1201 audit_log_format(ab, "audit(%lu.%03lu:%u): ",
1202 t.tv_sec, t.tv_nsec/1000000, serial);
1203 return ab;
1204}
1205
1206/**
1207 * audit_expand - expand skb in the audit buffer
1208 * @ab: audit_buffer
1209 * @extra: space to add at tail of the skb
1210 *
1211 * Returns 0 (no space) on failed expansion, or available space if
1212 * successful.
1213 */
1214static inline int audit_expand(struct audit_buffer *ab, int extra)
1215{
1216 struct sk_buff *skb = ab->skb;
1217 int oldtail = skb_tailroom(skb);
1218 int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1219 int newtail = skb_tailroom(skb);
1220
1221 if (ret < 0) {
1222 audit_log_lost("out of memory in audit_expand");
1223 return 0;
1224 }
1225
1226 skb->truesize += newtail - oldtail;
1227 return newtail;
1228}
1229
1230/*
1231 * Format an audit message into the audit buffer. If there isn't enough
1232 * room in the audit buffer, more room will be allocated and vsnprint
1233 * will be called a second time. Currently, we assume that a printk
1234 * can't format message larger than 1024 bytes, so we don't either.
1235 */
1236static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1237 va_list args)
1238{
1239 int len, avail;
1240 struct sk_buff *skb;
1241 va_list args2;
1242
1243 if (!ab)
1244 return;
1245
1246 BUG_ON(!ab->skb);
1247 skb = ab->skb;
1248 avail = skb_tailroom(skb);
1249 if (avail == 0) {
1250 avail = audit_expand(ab, AUDIT_BUFSIZ);
1251 if (!avail)
1252 goto out;
1253 }
1254 va_copy(args2, args);
1255 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1256 if (len >= avail) {
1257 /* The printk buffer is 1024 bytes long, so if we get
1258 * here and AUDIT_BUFSIZ is at least 1024, then we can
1259 * log everything that printk could have logged. */
1260 avail = audit_expand(ab,
1261 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1262 if (!avail)
1263 goto out;
1264 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1265 }
1266 va_end(args2);
1267 if (len > 0)
1268 skb_put(skb, len);
1269out:
1270 return;
1271}
1272
1273/**
1274 * audit_log_format - format a message into the audit buffer.
1275 * @ab: audit_buffer
1276 * @fmt: format string
1277 * @...: optional parameters matching @fmt string
1278 *
1279 * All the work is done in audit_log_vformat.
1280 */
1281void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1282{
1283 va_list args;
1284
1285 if (!ab)
1286 return;
1287 va_start(args, fmt);
1288 audit_log_vformat(ab, fmt, args);
1289 va_end(args);
1290}
1291
1292/**
1293 * audit_log_hex - convert a buffer to hex and append it to the audit skb
1294 * @ab: the audit_buffer
1295 * @buf: buffer to convert to hex
1296 * @len: length of @buf to be converted
1297 *
1298 * No return value; failure to expand is silently ignored.
1299 *
1300 * This function will take the passed buf and convert it into a string of
1301 * ascii hex digits. The new string is placed onto the skb.
1302 */
1303void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
1304 size_t len)
1305{
1306 int i, avail, new_len;
1307 unsigned char *ptr;
1308 struct sk_buff *skb;
1309 static const unsigned char *hex = "0123456789ABCDEF";
1310
1311 if (!ab)
1312 return;
1313
1314 BUG_ON(!ab->skb);
1315 skb = ab->skb;
1316 avail = skb_tailroom(skb);
1317 new_len = len<<1;
1318 if (new_len >= avail) {
1319 /* Round the buffer request up to the next multiple */
1320 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1321 avail = audit_expand(ab, new_len);
1322 if (!avail)
1323 return;
1324 }
1325
1326 ptr = skb_tail_pointer(skb);
1327 for (i=0; i<len; i++) {
1328 *ptr++ = hex[(buf[i] & 0xF0)>>4]; /* Upper nibble */
1329 *ptr++ = hex[buf[i] & 0x0F]; /* Lower nibble */
1330 }
1331 *ptr = 0;
1332 skb_put(skb, len << 1); /* new string is twice the old string */
1333}
1334
1335/*
1336 * Format a string of no more than slen characters into the audit buffer,
1337 * enclosed in quote marks.
1338 */
1339void audit_log_n_string(struct audit_buffer *ab, const char *string,
1340 size_t slen)
1341{
1342 int avail, new_len;
1343 unsigned char *ptr;
1344 struct sk_buff *skb;
1345
1346 if (!ab)
1347 return;
1348
1349 BUG_ON(!ab->skb);
1350 skb = ab->skb;
1351 avail = skb_tailroom(skb);
1352 new_len = slen + 3; /* enclosing quotes + null terminator */
1353 if (new_len > avail) {
1354 avail = audit_expand(ab, new_len);
1355 if (!avail)
1356 return;
1357 }
1358 ptr = skb_tail_pointer(skb);
1359 *ptr++ = '"';
1360 memcpy(ptr, string, slen);
1361 ptr += slen;
1362 *ptr++ = '"';
1363 *ptr = 0;
1364 skb_put(skb, slen + 2); /* don't include null terminator */
1365}
1366
1367/**
1368 * audit_string_contains_control - does a string need to be logged in hex
1369 * @string: string to be checked
1370 * @len: max length of the string to check
1371 */
1372int audit_string_contains_control(const char *string, size_t len)
1373{
1374 const unsigned char *p;
1375 for (p = string; p < (const unsigned char *)string + len; p++) {
1376 if (*p == '"' || *p < 0x21 || *p > 0x7e)
1377 return 1;
1378 }
1379 return 0;
1380}
1381
1382/**
1383 * audit_log_n_untrustedstring - log a string that may contain random characters
1384 * @ab: audit_buffer
1385 * @len: length of string (not including trailing null)
1386 * @string: string to be logged
1387 *
1388 * This code will escape a string that is passed to it if the string
1389 * contains a control character, unprintable character, double quote mark,
1390 * or a space. Unescaped strings will start and end with a double quote mark.
1391 * Strings that are escaped are printed in hex (2 digits per char).
1392 *
1393 * The caller specifies the number of characters in the string to log, which may
1394 * or may not be the entire string.
1395 */
1396void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
1397 size_t len)
1398{
1399 if (audit_string_contains_control(string, len))
1400 audit_log_n_hex(ab, string, len);
1401 else
1402 audit_log_n_string(ab, string, len);
1403}
1404
1405/**
1406 * audit_log_untrustedstring - log a string that may contain random characters
1407 * @ab: audit_buffer
1408 * @string: string to be logged
1409 *
1410 * Same as audit_log_n_untrustedstring(), except that strlen is used to
1411 * determine string length.
1412 */
1413void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
1414{
1415 audit_log_n_untrustedstring(ab, string, strlen(string));
1416}
1417
1418/* This is a helper-function to print the escaped d_path */
1419void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
1420 struct path *path)
1421{
1422 char *p, *pathname;
1423
1424 if (prefix)
1425 audit_log_format(ab, " %s", prefix);
1426
1427 /* We will allow 11 spaces for ' (deleted)' to be appended */
1428 pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
1429 if (!pathname) {
1430 audit_log_string(ab, "<no_memory>");
1431 return;
1432 }
1433 p = d_path(path, pathname, PATH_MAX+11);
1434 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
1435 /* FIXME: can we save some information here? */
1436 audit_log_string(ab, "<too_long>");
1437 } else
1438 audit_log_untrustedstring(ab, p);
1439 kfree(pathname);
1440}
1441
1442void audit_log_key(struct audit_buffer *ab, char *key)
1443{
1444 audit_log_format(ab, " key=");
1445 if (key)
1446 audit_log_untrustedstring(ab, key);
1447 else
1448 audit_log_format(ab, "(null)");
1449}
1450
1451/**
1452 * audit_log_end - end one audit record
1453 * @ab: the audit_buffer
1454 *
1455 * The netlink_* functions cannot be called inside an irq context, so
1456 * the audit buffer is placed on a queue and a tasklet is scheduled to
1457 * remove them from the queue outside the irq context. May be called in
1458 * any context.
1459 */
1460void audit_log_end(struct audit_buffer *ab)
1461{
1462 if (!ab)
1463 return;
1464 if (!audit_rate_check()) {
1465 audit_log_lost("rate limit exceeded");
1466 } else {
1467 struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
1468 nlh->nlmsg_len = ab->skb->len - NLMSG_SPACE(0);
1469
1470 if (audit_pid) {
1471 skb_queue_tail(&audit_skb_queue, ab->skb);
1472 wake_up_interruptible(&kauditd_wait);
1473 } else {
1474 audit_printk_skb(ab->skb);
1475 }
1476 ab->skb = NULL;
1477 }
1478 audit_buffer_free(ab);
1479}
1480
1481/**
1482 * audit_log - Log an audit record
1483 * @ctx: audit context
1484 * @gfp_mask: type of allocation
1485 * @type: audit message type
1486 * @fmt: format string to use
1487 * @...: variable parameters matching the format string
1488 *
1489 * This is a convenience function that calls audit_log_start,
1490 * audit_log_vformat, and audit_log_end. It may be called
1491 * in any context.
1492 */
1493void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
1494 const char *fmt, ...)
1495{
1496 struct audit_buffer *ab;
1497 va_list args;
1498
1499 ab = audit_log_start(ctx, gfp_mask, type);
1500 if (ab) {
1501 va_start(args, fmt);
1502 audit_log_vformat(ab, fmt, args);
1503 va_end(args);
1504 audit_log_end(ab);
1505 }
1506}
1507
1508#ifdef CONFIG_SECURITY
1509/**
1510 * audit_log_secctx - Converts and logs SELinux context
1511 * @ab: audit_buffer
1512 * @secid: security number
1513 *
1514 * This is a helper function that calls security_secid_to_secctx to convert
1515 * secid to secctx and then adds the (converted) SELinux context to the audit
1516 * log by calling audit_log_format, thus also preventing leak of internal secid
1517 * to userspace. If secid cannot be converted audit_panic is called.
1518 */
1519void audit_log_secctx(struct audit_buffer *ab, u32 secid)
1520{
1521 u32 len;
1522 char *secctx;
1523
1524 if (security_secid_to_secctx(secid, &secctx, &len)) {
1525 audit_panic("Cannot convert secid to context");
1526 } else {
1527 audit_log_format(ab, " obj=%s", secctx);
1528 security_release_secctx(secctx, len);
1529 }
1530}
1531EXPORT_SYMBOL(audit_log_secctx);
1532#endif
1533
1534EXPORT_SYMBOL(audit_log_start);
1535EXPORT_SYMBOL(audit_log_end);
1536EXPORT_SYMBOL(audit_log_format);
1537EXPORT_SYMBOL(audit_log);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/* audit.c -- Auditing support
3 * Gateway between the kernel (e.g., selinux) and the user-space audit daemon.
4 * System-call specific features have moved to auditsc.c
5 *
6 * Copyright 2003-2007 Red Hat Inc., Durham, North Carolina.
7 * All Rights Reserved.
8 *
9 * Written by Rickard E. (Rik) Faith <faith@redhat.com>
10 *
11 * Goals: 1) Integrate fully with Security Modules.
12 * 2) Minimal run-time overhead:
13 * a) Minimal when syscall auditing is disabled (audit_enable=0).
14 * b) Small when syscall auditing is enabled and no audit record
15 * is generated (defer as much work as possible to record
16 * generation time):
17 * i) context is allocated,
18 * ii) names from getname are stored without a copy, and
19 * iii) inode information stored from path_lookup.
20 * 3) Ability to disable syscall auditing at boot time (audit=0).
21 * 4) Usable by other parts of the kernel (if audit_log* is called,
22 * then a syscall record will be generated automatically for the
23 * current syscall).
24 * 5) Netlink interface to user-space.
25 * 6) Support low-overhead kernel-based filtering to minimize the
26 * information that must be passed to user-space.
27 *
28 * Audit userspace, documentation, tests, and bug/issue trackers:
29 * https://github.com/linux-audit
30 */
31
32#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
33
34#include <linux/file.h>
35#include <linux/init.h>
36#include <linux/types.h>
37#include <linux/atomic.h>
38#include <linux/mm.h>
39#include <linux/export.h>
40#include <linux/slab.h>
41#include <linux/err.h>
42#include <linux/kthread.h>
43#include <linux/kernel.h>
44#include <linux/syscalls.h>
45#include <linux/spinlock.h>
46#include <linux/rcupdate.h>
47#include <linux/mutex.h>
48#include <linux/gfp.h>
49#include <linux/pid.h>
50
51#include <linux/audit.h>
52
53#include <net/sock.h>
54#include <net/netlink.h>
55#include <linux/skbuff.h>
56#ifdef CONFIG_SECURITY
57#include <linux/security.h>
58#endif
59#include <linux/freezer.h>
60#include <linux/pid_namespace.h>
61#include <net/netns/generic.h>
62
63#include "audit.h"
64
65/* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
66 * (Initialization happens after skb_init is called.) */
67#define AUDIT_DISABLED -1
68#define AUDIT_UNINITIALIZED 0
69#define AUDIT_INITIALIZED 1
70static int audit_initialized;
71
72u32 audit_enabled = AUDIT_OFF;
73bool audit_ever_enabled = !!AUDIT_OFF;
74
75EXPORT_SYMBOL_GPL(audit_enabled);
76
77/* Default state when kernel boots without any parameters. */
78static u32 audit_default = AUDIT_OFF;
79
80/* If auditing cannot proceed, audit_failure selects what happens. */
81static u32 audit_failure = AUDIT_FAIL_PRINTK;
82
83/* private audit network namespace index */
84static unsigned int audit_net_id;
85
86/**
87 * struct audit_net - audit private network namespace data
88 * @sk: communication socket
89 */
90struct audit_net {
91 struct sock *sk;
92};
93
94/**
95 * struct auditd_connection - kernel/auditd connection state
96 * @pid: auditd PID
97 * @portid: netlink portid
98 * @net: the associated network namespace
99 * @rcu: RCU head
100 *
101 * Description:
102 * This struct is RCU protected; you must either hold the RCU lock for reading
103 * or the associated spinlock for writing.
104 */
105struct auditd_connection {
106 struct pid *pid;
107 u32 portid;
108 struct net *net;
109 struct rcu_head rcu;
110};
111static struct auditd_connection __rcu *auditd_conn;
112static DEFINE_SPINLOCK(auditd_conn_lock);
113
114/* If audit_rate_limit is non-zero, limit the rate of sending audit records
115 * to that number per second. This prevents DoS attacks, but results in
116 * audit records being dropped. */
117static u32 audit_rate_limit;
118
119/* Number of outstanding audit_buffers allowed.
120 * When set to zero, this means unlimited. */
121static u32 audit_backlog_limit = 64;
122#define AUDIT_BACKLOG_WAIT_TIME (60 * HZ)
123static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
124
125/* The identity of the user shutting down the audit system. */
126kuid_t audit_sig_uid = INVALID_UID;
127pid_t audit_sig_pid = -1;
128u32 audit_sig_sid = 0;
129
130/* Records can be lost in several ways:
131 0) [suppressed in audit_alloc]
132 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
133 2) out of memory in audit_log_move [alloc_skb]
134 3) suppressed due to audit_rate_limit
135 4) suppressed due to audit_backlog_limit
136*/
137static atomic_t audit_lost = ATOMIC_INIT(0);
138
139/* Monotonically increasing sum of time the kernel has spent
140 * waiting while the backlog limit is exceeded.
141 */
142static atomic_t audit_backlog_wait_time_actual = ATOMIC_INIT(0);
143
144/* Hash for inode-based rules */
145struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
146
147static struct kmem_cache *audit_buffer_cache;
148
149/* queue msgs to send via kauditd_task */
150static struct sk_buff_head audit_queue;
151/* queue msgs due to temporary unicast send problems */
152static struct sk_buff_head audit_retry_queue;
153/* queue msgs waiting for new auditd connection */
154static struct sk_buff_head audit_hold_queue;
155
156/* queue servicing thread */
157static struct task_struct *kauditd_task;
158static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
159
160/* waitqueue for callers who are blocked on the audit backlog */
161static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
162
163static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION,
164 .mask = -1,
165 .features = 0,
166 .lock = 0,};
167
168static char *audit_feature_names[2] = {
169 "only_unset_loginuid",
170 "loginuid_immutable",
171};
172
173/**
174 * struct audit_ctl_mutex - serialize requests from userspace
175 * @lock: the mutex used for locking
176 * @owner: the task which owns the lock
177 *
178 * Description:
179 * This is the lock struct used to ensure we only process userspace requests
180 * in an orderly fashion. We can't simply use a mutex/lock here because we
181 * need to track lock ownership so we don't end up blocking the lock owner in
182 * audit_log_start() or similar.
183 */
184static struct audit_ctl_mutex {
185 struct mutex lock;
186 void *owner;
187} audit_cmd_mutex;
188
189/* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
190 * audit records. Since printk uses a 1024 byte buffer, this buffer
191 * should be at least that large. */
192#define AUDIT_BUFSIZ 1024
193
194/* The audit_buffer is used when formatting an audit record. The caller
195 * locks briefly to get the record off the freelist or to allocate the
196 * buffer, and locks briefly to send the buffer to the netlink layer or
197 * to place it on a transmit queue. Multiple audit_buffers can be in
198 * use simultaneously. */
199struct audit_buffer {
200 struct sk_buff *skb; /* formatted skb ready to send */
201 struct audit_context *ctx; /* NULL or associated context */
202 gfp_t gfp_mask;
203};
204
205struct audit_reply {
206 __u32 portid;
207 struct net *net;
208 struct sk_buff *skb;
209};
210
211/**
212 * auditd_test_task - Check to see if a given task is an audit daemon
213 * @task: the task to check
214 *
215 * Description:
216 * Return 1 if the task is a registered audit daemon, 0 otherwise.
217 */
218int auditd_test_task(struct task_struct *task)
219{
220 int rc;
221 struct auditd_connection *ac;
222
223 rcu_read_lock();
224 ac = rcu_dereference(auditd_conn);
225 rc = (ac && ac->pid == task_tgid(task) ? 1 : 0);
226 rcu_read_unlock();
227
228 return rc;
229}
230
231/**
232 * audit_ctl_lock - Take the audit control lock
233 */
234void audit_ctl_lock(void)
235{
236 mutex_lock(&audit_cmd_mutex.lock);
237 audit_cmd_mutex.owner = current;
238}
239
240/**
241 * audit_ctl_unlock - Drop the audit control lock
242 */
243void audit_ctl_unlock(void)
244{
245 audit_cmd_mutex.owner = NULL;
246 mutex_unlock(&audit_cmd_mutex.lock);
247}
248
249/**
250 * audit_ctl_owner_current - Test to see if the current task owns the lock
251 *
252 * Description:
253 * Return true if the current task owns the audit control lock, false if it
254 * doesn't own the lock.
255 */
256static bool audit_ctl_owner_current(void)
257{
258 return (current == audit_cmd_mutex.owner);
259}
260
261/**
262 * auditd_pid_vnr - Return the auditd PID relative to the namespace
263 *
264 * Description:
265 * Returns the PID in relation to the namespace, 0 on failure.
266 */
267static pid_t auditd_pid_vnr(void)
268{
269 pid_t pid;
270 const struct auditd_connection *ac;
271
272 rcu_read_lock();
273 ac = rcu_dereference(auditd_conn);
274 if (!ac || !ac->pid)
275 pid = 0;
276 else
277 pid = pid_vnr(ac->pid);
278 rcu_read_unlock();
279
280 return pid;
281}
282
283/**
284 * audit_get_sk - Return the audit socket for the given network namespace
285 * @net: the destination network namespace
286 *
287 * Description:
288 * Returns the sock pointer if valid, NULL otherwise. The caller must ensure
289 * that a reference is held for the network namespace while the sock is in use.
290 */
291static struct sock *audit_get_sk(const struct net *net)
292{
293 struct audit_net *aunet;
294
295 if (!net)
296 return NULL;
297
298 aunet = net_generic(net, audit_net_id);
299 return aunet->sk;
300}
301
302void audit_panic(const char *message)
303{
304 switch (audit_failure) {
305 case AUDIT_FAIL_SILENT:
306 break;
307 case AUDIT_FAIL_PRINTK:
308 if (printk_ratelimit())
309 pr_err("%s\n", message);
310 break;
311 case AUDIT_FAIL_PANIC:
312 panic("audit: %s\n", message);
313 break;
314 }
315}
316
317static inline int audit_rate_check(void)
318{
319 static unsigned long last_check = 0;
320 static int messages = 0;
321 static DEFINE_SPINLOCK(lock);
322 unsigned long flags;
323 unsigned long now;
324 unsigned long elapsed;
325 int retval = 0;
326
327 if (!audit_rate_limit) return 1;
328
329 spin_lock_irqsave(&lock, flags);
330 if (++messages < audit_rate_limit) {
331 retval = 1;
332 } else {
333 now = jiffies;
334 elapsed = now - last_check;
335 if (elapsed > HZ) {
336 last_check = now;
337 messages = 0;
338 retval = 1;
339 }
340 }
341 spin_unlock_irqrestore(&lock, flags);
342
343 return retval;
344}
345
346/**
347 * audit_log_lost - conditionally log lost audit message event
348 * @message: the message stating reason for lost audit message
349 *
350 * Emit at least 1 message per second, even if audit_rate_check is
351 * throttling.
352 * Always increment the lost messages counter.
353*/
354void audit_log_lost(const char *message)
355{
356 static unsigned long last_msg = 0;
357 static DEFINE_SPINLOCK(lock);
358 unsigned long flags;
359 unsigned long now;
360 int print;
361
362 atomic_inc(&audit_lost);
363
364 print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
365
366 if (!print) {
367 spin_lock_irqsave(&lock, flags);
368 now = jiffies;
369 if (now - last_msg > HZ) {
370 print = 1;
371 last_msg = now;
372 }
373 spin_unlock_irqrestore(&lock, flags);
374 }
375
376 if (print) {
377 if (printk_ratelimit())
378 pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
379 atomic_read(&audit_lost),
380 audit_rate_limit,
381 audit_backlog_limit);
382 audit_panic(message);
383 }
384}
385
386static int audit_log_config_change(char *function_name, u32 new, u32 old,
387 int allow_changes)
388{
389 struct audit_buffer *ab;
390 int rc = 0;
391
392 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
393 if (unlikely(!ab))
394 return rc;
395 audit_log_format(ab, "op=set %s=%u old=%u ", function_name, new, old);
396 audit_log_session_info(ab);
397 rc = audit_log_task_context(ab);
398 if (rc)
399 allow_changes = 0; /* Something weird, deny request */
400 audit_log_format(ab, " res=%d", allow_changes);
401 audit_log_end(ab);
402 return rc;
403}
404
405static int audit_do_config_change(char *function_name, u32 *to_change, u32 new)
406{
407 int allow_changes, rc = 0;
408 u32 old = *to_change;
409
410 /* check if we are locked */
411 if (audit_enabled == AUDIT_LOCKED)
412 allow_changes = 0;
413 else
414 allow_changes = 1;
415
416 if (audit_enabled != AUDIT_OFF) {
417 rc = audit_log_config_change(function_name, new, old, allow_changes);
418 if (rc)
419 allow_changes = 0;
420 }
421
422 /* If we are allowed, make the change */
423 if (allow_changes == 1)
424 *to_change = new;
425 /* Not allowed, update reason */
426 else if (rc == 0)
427 rc = -EPERM;
428 return rc;
429}
430
431static int audit_set_rate_limit(u32 limit)
432{
433 return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit);
434}
435
436static int audit_set_backlog_limit(u32 limit)
437{
438 return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit);
439}
440
441static int audit_set_backlog_wait_time(u32 timeout)
442{
443 return audit_do_config_change("audit_backlog_wait_time",
444 &audit_backlog_wait_time, timeout);
445}
446
447static int audit_set_enabled(u32 state)
448{
449 int rc;
450 if (state > AUDIT_LOCKED)
451 return -EINVAL;
452
453 rc = audit_do_config_change("audit_enabled", &audit_enabled, state);
454 if (!rc)
455 audit_ever_enabled |= !!state;
456
457 return rc;
458}
459
460static int audit_set_failure(u32 state)
461{
462 if (state != AUDIT_FAIL_SILENT
463 && state != AUDIT_FAIL_PRINTK
464 && state != AUDIT_FAIL_PANIC)
465 return -EINVAL;
466
467 return audit_do_config_change("audit_failure", &audit_failure, state);
468}
469
470/**
471 * auditd_conn_free - RCU helper to release an auditd connection struct
472 * @rcu: RCU head
473 *
474 * Description:
475 * Drop any references inside the auditd connection tracking struct and free
476 * the memory.
477 */
478static void auditd_conn_free(struct rcu_head *rcu)
479{
480 struct auditd_connection *ac;
481
482 ac = container_of(rcu, struct auditd_connection, rcu);
483 put_pid(ac->pid);
484 put_net(ac->net);
485 kfree(ac);
486}
487
488/**
489 * auditd_set - Set/Reset the auditd connection state
490 * @pid: auditd PID
491 * @portid: auditd netlink portid
492 * @net: auditd network namespace pointer
493 *
494 * Description:
495 * This function will obtain and drop network namespace references as
496 * necessary. Returns zero on success, negative values on failure.
497 */
498static int auditd_set(struct pid *pid, u32 portid, struct net *net)
499{
500 unsigned long flags;
501 struct auditd_connection *ac_old, *ac_new;
502
503 if (!pid || !net)
504 return -EINVAL;
505
506 ac_new = kzalloc(sizeof(*ac_new), GFP_KERNEL);
507 if (!ac_new)
508 return -ENOMEM;
509 ac_new->pid = get_pid(pid);
510 ac_new->portid = portid;
511 ac_new->net = get_net(net);
512
513 spin_lock_irqsave(&auditd_conn_lock, flags);
514 ac_old = rcu_dereference_protected(auditd_conn,
515 lockdep_is_held(&auditd_conn_lock));
516 rcu_assign_pointer(auditd_conn, ac_new);
517 spin_unlock_irqrestore(&auditd_conn_lock, flags);
518
519 if (ac_old)
520 call_rcu(&ac_old->rcu, auditd_conn_free);
521
522 return 0;
523}
524
525/**
526 * kauditd_print_skb - Print the audit record to the ring buffer
527 * @skb: audit record
528 *
529 * Whatever the reason, this packet may not make it to the auditd connection
530 * so write it via printk so the information isn't completely lost.
531 */
532static void kauditd_printk_skb(struct sk_buff *skb)
533{
534 struct nlmsghdr *nlh = nlmsg_hdr(skb);
535 char *data = nlmsg_data(nlh);
536
537 if (nlh->nlmsg_type != AUDIT_EOE && printk_ratelimit())
538 pr_notice("type=%d %s\n", nlh->nlmsg_type, data);
539}
540
541/**
542 * kauditd_rehold_skb - Handle a audit record send failure in the hold queue
543 * @skb: audit record
544 *
545 * Description:
546 * This should only be used by the kauditd_thread when it fails to flush the
547 * hold queue.
548 */
549static void kauditd_rehold_skb(struct sk_buff *skb)
550{
551 /* put the record back in the queue at the same place */
552 skb_queue_head(&audit_hold_queue, skb);
553}
554
555/**
556 * kauditd_hold_skb - Queue an audit record, waiting for auditd
557 * @skb: audit record
558 *
559 * Description:
560 * Queue the audit record, waiting for an instance of auditd. When this
561 * function is called we haven't given up yet on sending the record, but things
562 * are not looking good. The first thing we want to do is try to write the
563 * record via printk and then see if we want to try and hold on to the record
564 * and queue it, if we have room. If we want to hold on to the record, but we
565 * don't have room, record a record lost message.
566 */
567static void kauditd_hold_skb(struct sk_buff *skb)
568{
569 /* at this point it is uncertain if we will ever send this to auditd so
570 * try to send the message via printk before we go any further */
571 kauditd_printk_skb(skb);
572
573 /* can we just silently drop the message? */
574 if (!audit_default) {
575 kfree_skb(skb);
576 return;
577 }
578
579 /* if we have room, queue the message */
580 if (!audit_backlog_limit ||
581 skb_queue_len(&audit_hold_queue) < audit_backlog_limit) {
582 skb_queue_tail(&audit_hold_queue, skb);
583 return;
584 }
585
586 /* we have no other options - drop the message */
587 audit_log_lost("kauditd hold queue overflow");
588 kfree_skb(skb);
589}
590
591/**
592 * kauditd_retry_skb - Queue an audit record, attempt to send again to auditd
593 * @skb: audit record
594 *
595 * Description:
596 * Not as serious as kauditd_hold_skb() as we still have a connected auditd,
597 * but for some reason we are having problems sending it audit records so
598 * queue the given record and attempt to resend.
599 */
600static void kauditd_retry_skb(struct sk_buff *skb)
601{
602 /* NOTE: because records should only live in the retry queue for a
603 * short period of time, before either being sent or moved to the hold
604 * queue, we don't currently enforce a limit on this queue */
605 skb_queue_tail(&audit_retry_queue, skb);
606}
607
608/**
609 * auditd_reset - Disconnect the auditd connection
610 * @ac: auditd connection state
611 *
612 * Description:
613 * Break the auditd/kauditd connection and move all the queued records into the
614 * hold queue in case auditd reconnects. It is important to note that the @ac
615 * pointer should never be dereferenced inside this function as it may be NULL
616 * or invalid, you can only compare the memory address! If @ac is NULL then
617 * the connection will always be reset.
618 */
619static void auditd_reset(const struct auditd_connection *ac)
620{
621 unsigned long flags;
622 struct sk_buff *skb;
623 struct auditd_connection *ac_old;
624
625 /* if it isn't already broken, break the connection */
626 spin_lock_irqsave(&auditd_conn_lock, flags);
627 ac_old = rcu_dereference_protected(auditd_conn,
628 lockdep_is_held(&auditd_conn_lock));
629 if (ac && ac != ac_old) {
630 /* someone already registered a new auditd connection */
631 spin_unlock_irqrestore(&auditd_conn_lock, flags);
632 return;
633 }
634 rcu_assign_pointer(auditd_conn, NULL);
635 spin_unlock_irqrestore(&auditd_conn_lock, flags);
636
637 if (ac_old)
638 call_rcu(&ac_old->rcu, auditd_conn_free);
639
640 /* flush the retry queue to the hold queue, but don't touch the main
641 * queue since we need to process that normally for multicast */
642 while ((skb = skb_dequeue(&audit_retry_queue)))
643 kauditd_hold_skb(skb);
644}
645
646/**
647 * auditd_send_unicast_skb - Send a record via unicast to auditd
648 * @skb: audit record
649 *
650 * Description:
651 * Send a skb to the audit daemon, returns positive/zero values on success and
652 * negative values on failure; in all cases the skb will be consumed by this
653 * function. If the send results in -ECONNREFUSED the connection with auditd
654 * will be reset. This function may sleep so callers should not hold any locks
655 * where this would cause a problem.
656 */
657static int auditd_send_unicast_skb(struct sk_buff *skb)
658{
659 int rc;
660 u32 portid;
661 struct net *net;
662 struct sock *sk;
663 struct auditd_connection *ac;
664
665 /* NOTE: we can't call netlink_unicast while in the RCU section so
666 * take a reference to the network namespace and grab local
667 * copies of the namespace, the sock, and the portid; the
668 * namespace and sock aren't going to go away while we hold a
669 * reference and if the portid does become invalid after the RCU
670 * section netlink_unicast() should safely return an error */
671
672 rcu_read_lock();
673 ac = rcu_dereference(auditd_conn);
674 if (!ac) {
675 rcu_read_unlock();
676 kfree_skb(skb);
677 rc = -ECONNREFUSED;
678 goto err;
679 }
680 net = get_net(ac->net);
681 sk = audit_get_sk(net);
682 portid = ac->portid;
683 rcu_read_unlock();
684
685 rc = netlink_unicast(sk, skb, portid, 0);
686 put_net(net);
687 if (rc < 0)
688 goto err;
689
690 return rc;
691
692err:
693 if (ac && rc == -ECONNREFUSED)
694 auditd_reset(ac);
695 return rc;
696}
697
698/**
699 * kauditd_send_queue - Helper for kauditd_thread to flush skb queues
700 * @sk: the sending sock
701 * @portid: the netlink destination
702 * @queue: the skb queue to process
703 * @retry_limit: limit on number of netlink unicast failures
704 * @skb_hook: per-skb hook for additional processing
705 * @err_hook: hook called if the skb fails the netlink unicast send
706 *
707 * Description:
708 * Run through the given queue and attempt to send the audit records to auditd,
709 * returns zero on success, negative values on failure. It is up to the caller
710 * to ensure that the @sk is valid for the duration of this function.
711 *
712 */
713static int kauditd_send_queue(struct sock *sk, u32 portid,
714 struct sk_buff_head *queue,
715 unsigned int retry_limit,
716 void (*skb_hook)(struct sk_buff *skb),
717 void (*err_hook)(struct sk_buff *skb))
718{
719 int rc = 0;
720 struct sk_buff *skb;
721 static unsigned int failed = 0;
722
723 /* NOTE: kauditd_thread takes care of all our locking, we just use
724 * the netlink info passed to us (e.g. sk and portid) */
725
726 while ((skb = skb_dequeue(queue))) {
727 /* call the skb_hook for each skb we touch */
728 if (skb_hook)
729 (*skb_hook)(skb);
730
731 /* can we send to anyone via unicast? */
732 if (!sk) {
733 if (err_hook)
734 (*err_hook)(skb);
735 continue;
736 }
737
738 /* grab an extra skb reference in case of error */
739 skb_get(skb);
740 rc = netlink_unicast(sk, skb, portid, 0);
741 if (rc < 0) {
742 /* fatal failure for our queue flush attempt? */
743 if (++failed >= retry_limit ||
744 rc == -ECONNREFUSED || rc == -EPERM) {
745 /* yes - error processing for the queue */
746 sk = NULL;
747 if (err_hook)
748 (*err_hook)(skb);
749 if (!skb_hook)
750 goto out;
751 /* keep processing with the skb_hook */
752 continue;
753 } else
754 /* no - requeue to preserve ordering */
755 skb_queue_head(queue, skb);
756 } else {
757 /* it worked - drop the extra reference and continue */
758 consume_skb(skb);
759 failed = 0;
760 }
761 }
762
763out:
764 return (rc >= 0 ? 0 : rc);
765}
766
767/*
768 * kauditd_send_multicast_skb - Send a record to any multicast listeners
769 * @skb: audit record
770 *
771 * Description:
772 * Write a multicast message to anyone listening in the initial network
773 * namespace. This function doesn't consume an skb as might be expected since
774 * it has to copy it anyways.
775 */
776static void kauditd_send_multicast_skb(struct sk_buff *skb)
777{
778 struct sk_buff *copy;
779 struct sock *sock = audit_get_sk(&init_net);
780 struct nlmsghdr *nlh;
781
782 /* NOTE: we are not taking an additional reference for init_net since
783 * we don't have to worry about it going away */
784
785 if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
786 return;
787
788 /*
789 * The seemingly wasteful skb_copy() rather than bumping the refcount
790 * using skb_get() is necessary because non-standard mods are made to
791 * the skb by the original kaudit unicast socket send routine. The
792 * existing auditd daemon assumes this breakage. Fixing this would
793 * require co-ordinating a change in the established protocol between
794 * the kaudit kernel subsystem and the auditd userspace code. There is
795 * no reason for new multicast clients to continue with this
796 * non-compliance.
797 */
798 copy = skb_copy(skb, GFP_KERNEL);
799 if (!copy)
800 return;
801 nlh = nlmsg_hdr(copy);
802 nlh->nlmsg_len = skb->len;
803
804 nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL);
805}
806
807/**
808 * kauditd_thread - Worker thread to send audit records to userspace
809 * @dummy: unused
810 */
811static int kauditd_thread(void *dummy)
812{
813 int rc;
814 u32 portid = 0;
815 struct net *net = NULL;
816 struct sock *sk = NULL;
817 struct auditd_connection *ac;
818
819#define UNICAST_RETRIES 5
820
821 set_freezable();
822 while (!kthread_should_stop()) {
823 /* NOTE: see the lock comments in auditd_send_unicast_skb() */
824 rcu_read_lock();
825 ac = rcu_dereference(auditd_conn);
826 if (!ac) {
827 rcu_read_unlock();
828 goto main_queue;
829 }
830 net = get_net(ac->net);
831 sk = audit_get_sk(net);
832 portid = ac->portid;
833 rcu_read_unlock();
834
835 /* attempt to flush the hold queue */
836 rc = kauditd_send_queue(sk, portid,
837 &audit_hold_queue, UNICAST_RETRIES,
838 NULL, kauditd_rehold_skb);
839 if (rc < 0) {
840 sk = NULL;
841 auditd_reset(ac);
842 goto main_queue;
843 }
844
845 /* attempt to flush the retry queue */
846 rc = kauditd_send_queue(sk, portid,
847 &audit_retry_queue, UNICAST_RETRIES,
848 NULL, kauditd_hold_skb);
849 if (rc < 0) {
850 sk = NULL;
851 auditd_reset(ac);
852 goto main_queue;
853 }
854
855main_queue:
856 /* process the main queue - do the multicast send and attempt
857 * unicast, dump failed record sends to the retry queue; if
858 * sk == NULL due to previous failures we will just do the
859 * multicast send and move the record to the hold queue */
860 rc = kauditd_send_queue(sk, portid, &audit_queue, 1,
861 kauditd_send_multicast_skb,
862 (sk ?
863 kauditd_retry_skb : kauditd_hold_skb));
864 if (ac && rc < 0)
865 auditd_reset(ac);
866 sk = NULL;
867
868 /* drop our netns reference, no auditd sends past this line */
869 if (net) {
870 put_net(net);
871 net = NULL;
872 }
873
874 /* we have processed all the queues so wake everyone */
875 wake_up(&audit_backlog_wait);
876
877 /* NOTE: we want to wake up if there is anything on the queue,
878 * regardless of if an auditd is connected, as we need to
879 * do the multicast send and rotate records from the
880 * main queue to the retry/hold queues */
881 wait_event_freezable(kauditd_wait,
882 (skb_queue_len(&audit_queue) ? 1 : 0));
883 }
884
885 return 0;
886}
887
888int audit_send_list_thread(void *_dest)
889{
890 struct audit_netlink_list *dest = _dest;
891 struct sk_buff *skb;
892 struct sock *sk = audit_get_sk(dest->net);
893
894 /* wait for parent to finish and send an ACK */
895 audit_ctl_lock();
896 audit_ctl_unlock();
897
898 while ((skb = __skb_dequeue(&dest->q)) != NULL)
899 netlink_unicast(sk, skb, dest->portid, 0);
900
901 put_net(dest->net);
902 kfree(dest);
903
904 return 0;
905}
906
907struct sk_buff *audit_make_reply(int seq, int type, int done,
908 int multi, const void *payload, int size)
909{
910 struct sk_buff *skb;
911 struct nlmsghdr *nlh;
912 void *data;
913 int flags = multi ? NLM_F_MULTI : 0;
914 int t = done ? NLMSG_DONE : type;
915
916 skb = nlmsg_new(size, GFP_KERNEL);
917 if (!skb)
918 return NULL;
919
920 nlh = nlmsg_put(skb, 0, seq, t, size, flags);
921 if (!nlh)
922 goto out_kfree_skb;
923 data = nlmsg_data(nlh);
924 memcpy(data, payload, size);
925 return skb;
926
927out_kfree_skb:
928 kfree_skb(skb);
929 return NULL;
930}
931
932static void audit_free_reply(struct audit_reply *reply)
933{
934 if (!reply)
935 return;
936
937 if (reply->skb)
938 kfree_skb(reply->skb);
939 if (reply->net)
940 put_net(reply->net);
941 kfree(reply);
942}
943
944static int audit_send_reply_thread(void *arg)
945{
946 struct audit_reply *reply = (struct audit_reply *)arg;
947
948 audit_ctl_lock();
949 audit_ctl_unlock();
950
951 /* Ignore failure. It'll only happen if the sender goes away,
952 because our timeout is set to infinite. */
953 netlink_unicast(audit_get_sk(reply->net), reply->skb, reply->portid, 0);
954 reply->skb = NULL;
955 audit_free_reply(reply);
956 return 0;
957}
958
959/**
960 * audit_send_reply - send an audit reply message via netlink
961 * @request_skb: skb of request we are replying to (used to target the reply)
962 * @seq: sequence number
963 * @type: audit message type
964 * @done: done (last) flag
965 * @multi: multi-part message flag
966 * @payload: payload data
967 * @size: payload size
968 *
969 * Allocates a skb, builds the netlink message, and sends it to the port id.
970 */
971static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
972 int multi, const void *payload, int size)
973{
974 struct task_struct *tsk;
975 struct audit_reply *reply;
976
977 reply = kzalloc(sizeof(*reply), GFP_KERNEL);
978 if (!reply)
979 return;
980
981 reply->skb = audit_make_reply(seq, type, done, multi, payload, size);
982 if (!reply->skb)
983 goto err;
984 reply->net = get_net(sock_net(NETLINK_CB(request_skb).sk));
985 reply->portid = NETLINK_CB(request_skb).portid;
986
987 tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
988 if (IS_ERR(tsk))
989 goto err;
990
991 return;
992
993err:
994 audit_free_reply(reply);
995}
996
997/*
998 * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
999 * control messages.
1000 */
1001static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
1002{
1003 int err = 0;
1004
1005 /* Only support initial user namespace for now. */
1006 /*
1007 * We return ECONNREFUSED because it tricks userspace into thinking
1008 * that audit was not configured into the kernel. Lots of users
1009 * configure their PAM stack (because that's what the distro does)
1010 * to reject login if unable to send messages to audit. If we return
1011 * ECONNREFUSED the PAM stack thinks the kernel does not have audit
1012 * configured in and will let login proceed. If we return EPERM
1013 * userspace will reject all logins. This should be removed when we
1014 * support non init namespaces!!
1015 */
1016 if (current_user_ns() != &init_user_ns)
1017 return -ECONNREFUSED;
1018
1019 switch (msg_type) {
1020 case AUDIT_LIST:
1021 case AUDIT_ADD:
1022 case AUDIT_DEL:
1023 return -EOPNOTSUPP;
1024 case AUDIT_GET:
1025 case AUDIT_SET:
1026 case AUDIT_GET_FEATURE:
1027 case AUDIT_SET_FEATURE:
1028 case AUDIT_LIST_RULES:
1029 case AUDIT_ADD_RULE:
1030 case AUDIT_DEL_RULE:
1031 case AUDIT_SIGNAL_INFO:
1032 case AUDIT_TTY_GET:
1033 case AUDIT_TTY_SET:
1034 case AUDIT_TRIM:
1035 case AUDIT_MAKE_EQUIV:
1036 /* Only support auditd and auditctl in initial pid namespace
1037 * for now. */
1038 if (task_active_pid_ns(current) != &init_pid_ns)
1039 return -EPERM;
1040
1041 if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
1042 err = -EPERM;
1043 break;
1044 case AUDIT_USER:
1045 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1046 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1047 if (!netlink_capable(skb, CAP_AUDIT_WRITE))
1048 err = -EPERM;
1049 break;
1050 default: /* bad msg */
1051 err = -EINVAL;
1052 }
1053
1054 return err;
1055}
1056
1057static void audit_log_common_recv_msg(struct audit_context *context,
1058 struct audit_buffer **ab, u16 msg_type)
1059{
1060 uid_t uid = from_kuid(&init_user_ns, current_uid());
1061 pid_t pid = task_tgid_nr(current);
1062
1063 if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
1064 *ab = NULL;
1065 return;
1066 }
1067
1068 *ab = audit_log_start(context, GFP_KERNEL, msg_type);
1069 if (unlikely(!*ab))
1070 return;
1071 audit_log_format(*ab, "pid=%d uid=%u ", pid, uid);
1072 audit_log_session_info(*ab);
1073 audit_log_task_context(*ab);
1074}
1075
1076static inline void audit_log_user_recv_msg(struct audit_buffer **ab,
1077 u16 msg_type)
1078{
1079 audit_log_common_recv_msg(NULL, ab, msg_type);
1080}
1081
1082int is_audit_feature_set(int i)
1083{
1084 return af.features & AUDIT_FEATURE_TO_MASK(i);
1085}
1086
1087
1088static int audit_get_feature(struct sk_buff *skb)
1089{
1090 u32 seq;
1091
1092 seq = nlmsg_hdr(skb)->nlmsg_seq;
1093
1094 audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af));
1095
1096 return 0;
1097}
1098
1099static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
1100 u32 old_lock, u32 new_lock, int res)
1101{
1102 struct audit_buffer *ab;
1103
1104 if (audit_enabled == AUDIT_OFF)
1105 return;
1106
1107 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_FEATURE_CHANGE);
1108 if (!ab)
1109 return;
1110 audit_log_task_info(ab);
1111 audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
1112 audit_feature_names[which], !!old_feature, !!new_feature,
1113 !!old_lock, !!new_lock, res);
1114 audit_log_end(ab);
1115}
1116
1117static int audit_set_feature(struct audit_features *uaf)
1118{
1119 int i;
1120
1121 BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
1122
1123 /* if there is ever a version 2 we should handle that here */
1124
1125 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1126 u32 feature = AUDIT_FEATURE_TO_MASK(i);
1127 u32 old_feature, new_feature, old_lock, new_lock;
1128
1129 /* if we are not changing this feature, move along */
1130 if (!(feature & uaf->mask))
1131 continue;
1132
1133 old_feature = af.features & feature;
1134 new_feature = uaf->features & feature;
1135 new_lock = (uaf->lock | af.lock) & feature;
1136 old_lock = af.lock & feature;
1137
1138 /* are we changing a locked feature? */
1139 if (old_lock && (new_feature != old_feature)) {
1140 audit_log_feature_change(i, old_feature, new_feature,
1141 old_lock, new_lock, 0);
1142 return -EPERM;
1143 }
1144 }
1145 /* nothing invalid, do the changes */
1146 for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
1147 u32 feature = AUDIT_FEATURE_TO_MASK(i);
1148 u32 old_feature, new_feature, old_lock, new_lock;
1149
1150 /* if we are not changing this feature, move along */
1151 if (!(feature & uaf->mask))
1152 continue;
1153
1154 old_feature = af.features & feature;
1155 new_feature = uaf->features & feature;
1156 old_lock = af.lock & feature;
1157 new_lock = (uaf->lock | af.lock) & feature;
1158
1159 if (new_feature != old_feature)
1160 audit_log_feature_change(i, old_feature, new_feature,
1161 old_lock, new_lock, 1);
1162
1163 if (new_feature)
1164 af.features |= feature;
1165 else
1166 af.features &= ~feature;
1167 af.lock |= new_lock;
1168 }
1169
1170 return 0;
1171}
1172
1173static int audit_replace(struct pid *pid)
1174{
1175 pid_t pvnr;
1176 struct sk_buff *skb;
1177
1178 pvnr = pid_vnr(pid);
1179 skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pvnr, sizeof(pvnr));
1180 if (!skb)
1181 return -ENOMEM;
1182 return auditd_send_unicast_skb(skb);
1183}
1184
1185static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
1186{
1187 u32 seq;
1188 void *data;
1189 int data_len;
1190 int err;
1191 struct audit_buffer *ab;
1192 u16 msg_type = nlh->nlmsg_type;
1193 struct audit_sig_info *sig_data;
1194 char *ctx = NULL;
1195 u32 len;
1196
1197 err = audit_netlink_ok(skb, msg_type);
1198 if (err)
1199 return err;
1200
1201 seq = nlh->nlmsg_seq;
1202 data = nlmsg_data(nlh);
1203 data_len = nlmsg_len(nlh);
1204
1205 switch (msg_type) {
1206 case AUDIT_GET: {
1207 struct audit_status s;
1208 memset(&s, 0, sizeof(s));
1209 s.enabled = audit_enabled;
1210 s.failure = audit_failure;
1211 /* NOTE: use pid_vnr() so the PID is relative to the current
1212 * namespace */
1213 s.pid = auditd_pid_vnr();
1214 s.rate_limit = audit_rate_limit;
1215 s.backlog_limit = audit_backlog_limit;
1216 s.lost = atomic_read(&audit_lost);
1217 s.backlog = skb_queue_len(&audit_queue);
1218 s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL;
1219 s.backlog_wait_time = audit_backlog_wait_time;
1220 s.backlog_wait_time_actual = atomic_read(&audit_backlog_wait_time_actual);
1221 audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
1222 break;
1223 }
1224 case AUDIT_SET: {
1225 struct audit_status s;
1226 memset(&s, 0, sizeof(s));
1227 /* guard against past and future API changes */
1228 memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
1229 if (s.mask & AUDIT_STATUS_ENABLED) {
1230 err = audit_set_enabled(s.enabled);
1231 if (err < 0)
1232 return err;
1233 }
1234 if (s.mask & AUDIT_STATUS_FAILURE) {
1235 err = audit_set_failure(s.failure);
1236 if (err < 0)
1237 return err;
1238 }
1239 if (s.mask & AUDIT_STATUS_PID) {
1240 /* NOTE: we are using the vnr PID functions below
1241 * because the s.pid value is relative to the
1242 * namespace of the caller; at present this
1243 * doesn't matter much since you can really only
1244 * run auditd from the initial pid namespace, but
1245 * something to keep in mind if this changes */
1246 pid_t new_pid = s.pid;
1247 pid_t auditd_pid;
1248 struct pid *req_pid = task_tgid(current);
1249
1250 /* Sanity check - PID values must match. Setting
1251 * pid to 0 is how auditd ends auditing. */
1252 if (new_pid && (new_pid != pid_vnr(req_pid)))
1253 return -EINVAL;
1254
1255 /* test the auditd connection */
1256 audit_replace(req_pid);
1257
1258 auditd_pid = auditd_pid_vnr();
1259 if (auditd_pid) {
1260 /* replacing a healthy auditd is not allowed */
1261 if (new_pid) {
1262 audit_log_config_change("audit_pid",
1263 new_pid, auditd_pid, 0);
1264 return -EEXIST;
1265 }
1266 /* only current auditd can unregister itself */
1267 if (pid_vnr(req_pid) != auditd_pid) {
1268 audit_log_config_change("audit_pid",
1269 new_pid, auditd_pid, 0);
1270 return -EACCES;
1271 }
1272 }
1273
1274 if (new_pid) {
1275 /* register a new auditd connection */
1276 err = auditd_set(req_pid,
1277 NETLINK_CB(skb).portid,
1278 sock_net(NETLINK_CB(skb).sk));
1279 if (audit_enabled != AUDIT_OFF)
1280 audit_log_config_change("audit_pid",
1281 new_pid,
1282 auditd_pid,
1283 err ? 0 : 1);
1284 if (err)
1285 return err;
1286
1287 /* try to process any backlog */
1288 wake_up_interruptible(&kauditd_wait);
1289 } else {
1290 if (audit_enabled != AUDIT_OFF)
1291 audit_log_config_change("audit_pid",
1292 new_pid,
1293 auditd_pid, 1);
1294
1295 /* unregister the auditd connection */
1296 auditd_reset(NULL);
1297 }
1298 }
1299 if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
1300 err = audit_set_rate_limit(s.rate_limit);
1301 if (err < 0)
1302 return err;
1303 }
1304 if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
1305 err = audit_set_backlog_limit(s.backlog_limit);
1306 if (err < 0)
1307 return err;
1308 }
1309 if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
1310 if (sizeof(s) > (size_t)nlh->nlmsg_len)
1311 return -EINVAL;
1312 if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
1313 return -EINVAL;
1314 err = audit_set_backlog_wait_time(s.backlog_wait_time);
1315 if (err < 0)
1316 return err;
1317 }
1318 if (s.mask == AUDIT_STATUS_LOST) {
1319 u32 lost = atomic_xchg(&audit_lost, 0);
1320
1321 audit_log_config_change("lost", 0, lost, 1);
1322 return lost;
1323 }
1324 if (s.mask == AUDIT_STATUS_BACKLOG_WAIT_TIME_ACTUAL) {
1325 u32 actual = atomic_xchg(&audit_backlog_wait_time_actual, 0);
1326
1327 audit_log_config_change("backlog_wait_time_actual", 0, actual, 1);
1328 return actual;
1329 }
1330 break;
1331 }
1332 case AUDIT_GET_FEATURE:
1333 err = audit_get_feature(skb);
1334 if (err)
1335 return err;
1336 break;
1337 case AUDIT_SET_FEATURE:
1338 if (data_len < sizeof(struct audit_features))
1339 return -EINVAL;
1340 err = audit_set_feature(data);
1341 if (err)
1342 return err;
1343 break;
1344 case AUDIT_USER:
1345 case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
1346 case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
1347 if (!audit_enabled && msg_type != AUDIT_USER_AVC)
1348 return 0;
1349 /* exit early if there isn't at least one character to print */
1350 if (data_len < 2)
1351 return -EINVAL;
1352
1353 err = audit_filter(msg_type, AUDIT_FILTER_USER);
1354 if (err == 1) { /* match or error */
1355 char *str = data;
1356
1357 err = 0;
1358 if (msg_type == AUDIT_USER_TTY) {
1359 err = tty_audit_push();
1360 if (err)
1361 break;
1362 }
1363 audit_log_user_recv_msg(&ab, msg_type);
1364 if (msg_type != AUDIT_USER_TTY) {
1365 /* ensure NULL termination */
1366 str[data_len - 1] = '\0';
1367 audit_log_format(ab, " msg='%.*s'",
1368 AUDIT_MESSAGE_TEXT_MAX,
1369 str);
1370 } else {
1371 audit_log_format(ab, " data=");
1372 if (data_len > 0 && str[data_len - 1] == '\0')
1373 data_len--;
1374 audit_log_n_untrustedstring(ab, str, data_len);
1375 }
1376 audit_log_end(ab);
1377 }
1378 break;
1379 case AUDIT_ADD_RULE:
1380 case AUDIT_DEL_RULE:
1381 if (data_len < sizeof(struct audit_rule_data))
1382 return -EINVAL;
1383 if (audit_enabled == AUDIT_LOCKED) {
1384 audit_log_common_recv_msg(audit_context(), &ab,
1385 AUDIT_CONFIG_CHANGE);
1386 audit_log_format(ab, " op=%s audit_enabled=%d res=0",
1387 msg_type == AUDIT_ADD_RULE ?
1388 "add_rule" : "remove_rule",
1389 audit_enabled);
1390 audit_log_end(ab);
1391 return -EPERM;
1392 }
1393 err = audit_rule_change(msg_type, seq, data, data_len);
1394 break;
1395 case AUDIT_LIST_RULES:
1396 err = audit_list_rules_send(skb, seq);
1397 break;
1398 case AUDIT_TRIM:
1399 audit_trim_trees();
1400 audit_log_common_recv_msg(audit_context(), &ab,
1401 AUDIT_CONFIG_CHANGE);
1402 audit_log_format(ab, " op=trim res=1");
1403 audit_log_end(ab);
1404 break;
1405 case AUDIT_MAKE_EQUIV: {
1406 void *bufp = data;
1407 u32 sizes[2];
1408 size_t msglen = data_len;
1409 char *old, *new;
1410
1411 err = -EINVAL;
1412 if (msglen < 2 * sizeof(u32))
1413 break;
1414 memcpy(sizes, bufp, 2 * sizeof(u32));
1415 bufp += 2 * sizeof(u32);
1416 msglen -= 2 * sizeof(u32);
1417 old = audit_unpack_string(&bufp, &msglen, sizes[0]);
1418 if (IS_ERR(old)) {
1419 err = PTR_ERR(old);
1420 break;
1421 }
1422 new = audit_unpack_string(&bufp, &msglen, sizes[1]);
1423 if (IS_ERR(new)) {
1424 err = PTR_ERR(new);
1425 kfree(old);
1426 break;
1427 }
1428 /* OK, here comes... */
1429 err = audit_tag_tree(old, new);
1430
1431 audit_log_common_recv_msg(audit_context(), &ab,
1432 AUDIT_CONFIG_CHANGE);
1433 audit_log_format(ab, " op=make_equiv old=");
1434 audit_log_untrustedstring(ab, old);
1435 audit_log_format(ab, " new=");
1436 audit_log_untrustedstring(ab, new);
1437 audit_log_format(ab, " res=%d", !err);
1438 audit_log_end(ab);
1439 kfree(old);
1440 kfree(new);
1441 break;
1442 }
1443 case AUDIT_SIGNAL_INFO:
1444 len = 0;
1445 if (audit_sig_sid) {
1446 err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
1447 if (err)
1448 return err;
1449 }
1450 sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
1451 if (!sig_data) {
1452 if (audit_sig_sid)
1453 security_release_secctx(ctx, len);
1454 return -ENOMEM;
1455 }
1456 sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
1457 sig_data->pid = audit_sig_pid;
1458 if (audit_sig_sid) {
1459 memcpy(sig_data->ctx, ctx, len);
1460 security_release_secctx(ctx, len);
1461 }
1462 audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
1463 sig_data, sizeof(*sig_data) + len);
1464 kfree(sig_data);
1465 break;
1466 case AUDIT_TTY_GET: {
1467 struct audit_tty_status s;
1468 unsigned int t;
1469
1470 t = READ_ONCE(current->signal->audit_tty);
1471 s.enabled = t & AUDIT_TTY_ENABLE;
1472 s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1473
1474 audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
1475 break;
1476 }
1477 case AUDIT_TTY_SET: {
1478 struct audit_tty_status s, old;
1479 struct audit_buffer *ab;
1480 unsigned int t;
1481
1482 memset(&s, 0, sizeof(s));
1483 /* guard against past and future API changes */
1484 memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
1485 /* check if new data is valid */
1486 if ((s.enabled != 0 && s.enabled != 1) ||
1487 (s.log_passwd != 0 && s.log_passwd != 1))
1488 err = -EINVAL;
1489
1490 if (err)
1491 t = READ_ONCE(current->signal->audit_tty);
1492 else {
1493 t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD);
1494 t = xchg(¤t->signal->audit_tty, t);
1495 }
1496 old.enabled = t & AUDIT_TTY_ENABLE;
1497 old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
1498
1499 audit_log_common_recv_msg(audit_context(), &ab,
1500 AUDIT_CONFIG_CHANGE);
1501 audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
1502 " old-log_passwd=%d new-log_passwd=%d res=%d",
1503 old.enabled, s.enabled, old.log_passwd,
1504 s.log_passwd, !err);
1505 audit_log_end(ab);
1506 break;
1507 }
1508 default:
1509 err = -EINVAL;
1510 break;
1511 }
1512
1513 return err < 0 ? err : 0;
1514}
1515
1516/**
1517 * audit_receive - receive messages from a netlink control socket
1518 * @skb: the message buffer
1519 *
1520 * Parse the provided skb and deal with any messages that may be present,
1521 * malformed skbs are discarded.
1522 */
1523static void audit_receive(struct sk_buff *skb)
1524{
1525 struct nlmsghdr *nlh;
1526 /*
1527 * len MUST be signed for nlmsg_next to be able to dec it below 0
1528 * if the nlmsg_len was not aligned
1529 */
1530 int len;
1531 int err;
1532
1533 nlh = nlmsg_hdr(skb);
1534 len = skb->len;
1535
1536 audit_ctl_lock();
1537 while (nlmsg_ok(nlh, len)) {
1538 err = audit_receive_msg(skb, nlh);
1539 /* if err or if this message says it wants a response */
1540 if (err || (nlh->nlmsg_flags & NLM_F_ACK))
1541 netlink_ack(skb, nlh, err, NULL);
1542
1543 nlh = nlmsg_next(nlh, &len);
1544 }
1545 audit_ctl_unlock();
1546}
1547
1548/* Log information about who is connecting to the audit multicast socket */
1549static void audit_log_multicast(int group, const char *op, int err)
1550{
1551 const struct cred *cred;
1552 struct tty_struct *tty;
1553 char comm[sizeof(current->comm)];
1554 struct audit_buffer *ab;
1555
1556 if (!audit_enabled)
1557 return;
1558
1559 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_EVENT_LISTENER);
1560 if (!ab)
1561 return;
1562
1563 cred = current_cred();
1564 tty = audit_get_tty();
1565 audit_log_format(ab, "pid=%u uid=%u auid=%u tty=%s ses=%u",
1566 task_pid_nr(current),
1567 from_kuid(&init_user_ns, cred->uid),
1568 from_kuid(&init_user_ns, audit_get_loginuid(current)),
1569 tty ? tty_name(tty) : "(none)",
1570 audit_get_sessionid(current));
1571 audit_put_tty(tty);
1572 audit_log_task_context(ab); /* subj= */
1573 audit_log_format(ab, " comm=");
1574 audit_log_untrustedstring(ab, get_task_comm(comm, current));
1575 audit_log_d_path_exe(ab, current->mm); /* exe= */
1576 audit_log_format(ab, " nl-mcgrp=%d op=%s res=%d", group, op, !err);
1577 audit_log_end(ab);
1578}
1579
1580/* Run custom bind function on netlink socket group connect or bind requests. */
1581static int audit_multicast_bind(struct net *net, int group)
1582{
1583 int err = 0;
1584
1585 if (!capable(CAP_AUDIT_READ))
1586 err = -EPERM;
1587 audit_log_multicast(group, "connect", err);
1588 return err;
1589}
1590
1591static void audit_multicast_unbind(struct net *net, int group)
1592{
1593 audit_log_multicast(group, "disconnect", 0);
1594}
1595
1596static int __net_init audit_net_init(struct net *net)
1597{
1598 struct netlink_kernel_cfg cfg = {
1599 .input = audit_receive,
1600 .bind = audit_multicast_bind,
1601 .unbind = audit_multicast_unbind,
1602 .flags = NL_CFG_F_NONROOT_RECV,
1603 .groups = AUDIT_NLGRP_MAX,
1604 };
1605
1606 struct audit_net *aunet = net_generic(net, audit_net_id);
1607
1608 aunet->sk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
1609 if (aunet->sk == NULL) {
1610 audit_panic("cannot initialize netlink socket in namespace");
1611 return -ENOMEM;
1612 }
1613 aunet->sk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
1614
1615 return 0;
1616}
1617
1618static void __net_exit audit_net_exit(struct net *net)
1619{
1620 struct audit_net *aunet = net_generic(net, audit_net_id);
1621
1622 /* NOTE: you would think that we would want to check the auditd
1623 * connection and potentially reset it here if it lives in this
1624 * namespace, but since the auditd connection tracking struct holds a
1625 * reference to this namespace (see auditd_set()) we are only ever
1626 * going to get here after that connection has been released */
1627
1628 netlink_kernel_release(aunet->sk);
1629}
1630
1631static struct pernet_operations audit_net_ops __net_initdata = {
1632 .init = audit_net_init,
1633 .exit = audit_net_exit,
1634 .id = &audit_net_id,
1635 .size = sizeof(struct audit_net),
1636};
1637
1638/* Initialize audit support at boot time. */
1639static int __init audit_init(void)
1640{
1641 int i;
1642
1643 if (audit_initialized == AUDIT_DISABLED)
1644 return 0;
1645
1646 audit_buffer_cache = kmem_cache_create("audit_buffer",
1647 sizeof(struct audit_buffer),
1648 0, SLAB_PANIC, NULL);
1649
1650 skb_queue_head_init(&audit_queue);
1651 skb_queue_head_init(&audit_retry_queue);
1652 skb_queue_head_init(&audit_hold_queue);
1653
1654 for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
1655 INIT_LIST_HEAD(&audit_inode_hash[i]);
1656
1657 mutex_init(&audit_cmd_mutex.lock);
1658 audit_cmd_mutex.owner = NULL;
1659
1660 pr_info("initializing netlink subsys (%s)\n",
1661 audit_default ? "enabled" : "disabled");
1662 register_pernet_subsys(&audit_net_ops);
1663
1664 audit_initialized = AUDIT_INITIALIZED;
1665
1666 kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
1667 if (IS_ERR(kauditd_task)) {
1668 int err = PTR_ERR(kauditd_task);
1669 panic("audit: failed to start the kauditd thread (%d)\n", err);
1670 }
1671
1672 audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL,
1673 "state=initialized audit_enabled=%u res=1",
1674 audit_enabled);
1675
1676 return 0;
1677}
1678postcore_initcall(audit_init);
1679
1680/*
1681 * Process kernel command-line parameter at boot time.
1682 * audit={0|off} or audit={1|on}.
1683 */
1684static int __init audit_enable(char *str)
1685{
1686 if (!strcasecmp(str, "off") || !strcmp(str, "0"))
1687 audit_default = AUDIT_OFF;
1688 else if (!strcasecmp(str, "on") || !strcmp(str, "1"))
1689 audit_default = AUDIT_ON;
1690 else {
1691 pr_err("audit: invalid 'audit' parameter value (%s)\n", str);
1692 audit_default = AUDIT_ON;
1693 }
1694
1695 if (audit_default == AUDIT_OFF)
1696 audit_initialized = AUDIT_DISABLED;
1697 if (audit_set_enabled(audit_default))
1698 pr_err("audit: error setting audit state (%d)\n",
1699 audit_default);
1700
1701 pr_info("%s\n", audit_default ?
1702 "enabled (after initialization)" : "disabled (until reboot)");
1703
1704 return 1;
1705}
1706__setup("audit=", audit_enable);
1707
1708/* Process kernel command-line parameter at boot time.
1709 * audit_backlog_limit=<n> */
1710static int __init audit_backlog_limit_set(char *str)
1711{
1712 u32 audit_backlog_limit_arg;
1713
1714 pr_info("audit_backlog_limit: ");
1715 if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
1716 pr_cont("using default of %u, unable to parse %s\n",
1717 audit_backlog_limit, str);
1718 return 1;
1719 }
1720
1721 audit_backlog_limit = audit_backlog_limit_arg;
1722 pr_cont("%d\n", audit_backlog_limit);
1723
1724 return 1;
1725}
1726__setup("audit_backlog_limit=", audit_backlog_limit_set);
1727
1728static void audit_buffer_free(struct audit_buffer *ab)
1729{
1730 if (!ab)
1731 return;
1732
1733 kfree_skb(ab->skb);
1734 kmem_cache_free(audit_buffer_cache, ab);
1735}
1736
1737static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx,
1738 gfp_t gfp_mask, int type)
1739{
1740 struct audit_buffer *ab;
1741
1742 ab = kmem_cache_alloc(audit_buffer_cache, gfp_mask);
1743 if (!ab)
1744 return NULL;
1745
1746 ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
1747 if (!ab->skb)
1748 goto err;
1749 if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0))
1750 goto err;
1751
1752 ab->ctx = ctx;
1753 ab->gfp_mask = gfp_mask;
1754
1755 return ab;
1756
1757err:
1758 audit_buffer_free(ab);
1759 return NULL;
1760}
1761
1762/**
1763 * audit_serial - compute a serial number for the audit record
1764 *
1765 * Compute a serial number for the audit record. Audit records are
1766 * written to user-space as soon as they are generated, so a complete
1767 * audit record may be written in several pieces. The timestamp of the
1768 * record and this serial number are used by the user-space tools to
1769 * determine which pieces belong to the same audit record. The
1770 * (timestamp,serial) tuple is unique for each syscall and is live from
1771 * syscall entry to syscall exit.
1772 *
1773 * NOTE: Another possibility is to store the formatted records off the
1774 * audit context (for those records that have a context), and emit them
1775 * all at syscall exit. However, this could delay the reporting of
1776 * significant errors until syscall exit (or never, if the system
1777 * halts).
1778 */
1779unsigned int audit_serial(void)
1780{
1781 static atomic_t serial = ATOMIC_INIT(0);
1782
1783 return atomic_add_return(1, &serial);
1784}
1785
1786static inline void audit_get_stamp(struct audit_context *ctx,
1787 struct timespec64 *t, unsigned int *serial)
1788{
1789 if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
1790 ktime_get_coarse_real_ts64(t);
1791 *serial = audit_serial();
1792 }
1793}
1794
1795/**
1796 * audit_log_start - obtain an audit buffer
1797 * @ctx: audit_context (may be NULL)
1798 * @gfp_mask: type of allocation
1799 * @type: audit message type
1800 *
1801 * Returns audit_buffer pointer on success or NULL on error.
1802 *
1803 * Obtain an audit buffer. This routine does locking to obtain the
1804 * audit buffer, but then no locking is required for calls to
1805 * audit_log_*format. If the task (ctx) is a task that is currently in a
1806 * syscall, then the syscall is marked as auditable and an audit record
1807 * will be written at syscall exit. If there is no associated task, then
1808 * task context (ctx) should be NULL.
1809 */
1810struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
1811 int type)
1812{
1813 struct audit_buffer *ab;
1814 struct timespec64 t;
1815 unsigned int serial;
1816
1817 if (audit_initialized != AUDIT_INITIALIZED)
1818 return NULL;
1819
1820 if (unlikely(!audit_filter(type, AUDIT_FILTER_EXCLUDE)))
1821 return NULL;
1822
1823 /* NOTE: don't ever fail/sleep on these two conditions:
1824 * 1. auditd generated record - since we need auditd to drain the
1825 * queue; also, when we are checking for auditd, compare PIDs using
1826 * task_tgid_vnr() since auditd_pid is set in audit_receive_msg()
1827 * using a PID anchored in the caller's namespace
1828 * 2. generator holding the audit_cmd_mutex - we don't want to block
1829 * while holding the mutex */
1830 if (!(auditd_test_task(current) || audit_ctl_owner_current())) {
1831 long stime = audit_backlog_wait_time;
1832
1833 while (audit_backlog_limit &&
1834 (skb_queue_len(&audit_queue) > audit_backlog_limit)) {
1835 /* wake kauditd to try and flush the queue */
1836 wake_up_interruptible(&kauditd_wait);
1837
1838 /* sleep if we are allowed and we haven't exhausted our
1839 * backlog wait limit */
1840 if (gfpflags_allow_blocking(gfp_mask) && (stime > 0)) {
1841 long rtime = stime;
1842
1843 DECLARE_WAITQUEUE(wait, current);
1844
1845 add_wait_queue_exclusive(&audit_backlog_wait,
1846 &wait);
1847 set_current_state(TASK_UNINTERRUPTIBLE);
1848 stime = schedule_timeout(rtime);
1849 atomic_add(rtime - stime, &audit_backlog_wait_time_actual);
1850 remove_wait_queue(&audit_backlog_wait, &wait);
1851 } else {
1852 if (audit_rate_check() && printk_ratelimit())
1853 pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
1854 skb_queue_len(&audit_queue),
1855 audit_backlog_limit);
1856 audit_log_lost("backlog limit exceeded");
1857 return NULL;
1858 }
1859 }
1860 }
1861
1862 ab = audit_buffer_alloc(ctx, gfp_mask, type);
1863 if (!ab) {
1864 audit_log_lost("out of memory in audit_log_start");
1865 return NULL;
1866 }
1867
1868 audit_get_stamp(ab->ctx, &t, &serial);
1869 audit_log_format(ab, "audit(%llu.%03lu:%u): ",
1870 (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
1871
1872 return ab;
1873}
1874
1875/**
1876 * audit_expand - expand skb in the audit buffer
1877 * @ab: audit_buffer
1878 * @extra: space to add at tail of the skb
1879 *
1880 * Returns 0 (no space) on failed expansion, or available space if
1881 * successful.
1882 */
1883static inline int audit_expand(struct audit_buffer *ab, int extra)
1884{
1885 struct sk_buff *skb = ab->skb;
1886 int oldtail = skb_tailroom(skb);
1887 int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
1888 int newtail = skb_tailroom(skb);
1889
1890 if (ret < 0) {
1891 audit_log_lost("out of memory in audit_expand");
1892 return 0;
1893 }
1894
1895 skb->truesize += newtail - oldtail;
1896 return newtail;
1897}
1898
1899/*
1900 * Format an audit message into the audit buffer. If there isn't enough
1901 * room in the audit buffer, more room will be allocated and vsnprint
1902 * will be called a second time. Currently, we assume that a printk
1903 * can't format message larger than 1024 bytes, so we don't either.
1904 */
1905static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
1906 va_list args)
1907{
1908 int len, avail;
1909 struct sk_buff *skb;
1910 va_list args2;
1911
1912 if (!ab)
1913 return;
1914
1915 BUG_ON(!ab->skb);
1916 skb = ab->skb;
1917 avail = skb_tailroom(skb);
1918 if (avail == 0) {
1919 avail = audit_expand(ab, AUDIT_BUFSIZ);
1920 if (!avail)
1921 goto out;
1922 }
1923 va_copy(args2, args);
1924 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
1925 if (len >= avail) {
1926 /* The printk buffer is 1024 bytes long, so if we get
1927 * here and AUDIT_BUFSIZ is at least 1024, then we can
1928 * log everything that printk could have logged. */
1929 avail = audit_expand(ab,
1930 max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
1931 if (!avail)
1932 goto out_va_end;
1933 len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
1934 }
1935 if (len > 0)
1936 skb_put(skb, len);
1937out_va_end:
1938 va_end(args2);
1939out:
1940 return;
1941}
1942
1943/**
1944 * audit_log_format - format a message into the audit buffer.
1945 * @ab: audit_buffer
1946 * @fmt: format string
1947 * @...: optional parameters matching @fmt string
1948 *
1949 * All the work is done in audit_log_vformat.
1950 */
1951void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
1952{
1953 va_list args;
1954
1955 if (!ab)
1956 return;
1957 va_start(args, fmt);
1958 audit_log_vformat(ab, fmt, args);
1959 va_end(args);
1960}
1961
1962/**
1963 * audit_log_n_hex - convert a buffer to hex and append it to the audit skb
1964 * @ab: the audit_buffer
1965 * @buf: buffer to convert to hex
1966 * @len: length of @buf to be converted
1967 *
1968 * No return value; failure to expand is silently ignored.
1969 *
1970 * This function will take the passed buf and convert it into a string of
1971 * ascii hex digits. The new string is placed onto the skb.
1972 */
1973void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
1974 size_t len)
1975{
1976 int i, avail, new_len;
1977 unsigned char *ptr;
1978 struct sk_buff *skb;
1979
1980 if (!ab)
1981 return;
1982
1983 BUG_ON(!ab->skb);
1984 skb = ab->skb;
1985 avail = skb_tailroom(skb);
1986 new_len = len<<1;
1987 if (new_len >= avail) {
1988 /* Round the buffer request up to the next multiple */
1989 new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
1990 avail = audit_expand(ab, new_len);
1991 if (!avail)
1992 return;
1993 }
1994
1995 ptr = skb_tail_pointer(skb);
1996 for (i = 0; i < len; i++)
1997 ptr = hex_byte_pack_upper(ptr, buf[i]);
1998 *ptr = 0;
1999 skb_put(skb, len << 1); /* new string is twice the old string */
2000}
2001
2002/*
2003 * Format a string of no more than slen characters into the audit buffer,
2004 * enclosed in quote marks.
2005 */
2006void audit_log_n_string(struct audit_buffer *ab, const char *string,
2007 size_t slen)
2008{
2009 int avail, new_len;
2010 unsigned char *ptr;
2011 struct sk_buff *skb;
2012
2013 if (!ab)
2014 return;
2015
2016 BUG_ON(!ab->skb);
2017 skb = ab->skb;
2018 avail = skb_tailroom(skb);
2019 new_len = slen + 3; /* enclosing quotes + null terminator */
2020 if (new_len > avail) {
2021 avail = audit_expand(ab, new_len);
2022 if (!avail)
2023 return;
2024 }
2025 ptr = skb_tail_pointer(skb);
2026 *ptr++ = '"';
2027 memcpy(ptr, string, slen);
2028 ptr += slen;
2029 *ptr++ = '"';
2030 *ptr = 0;
2031 skb_put(skb, slen + 2); /* don't include null terminator */
2032}
2033
2034/**
2035 * audit_string_contains_control - does a string need to be logged in hex
2036 * @string: string to be checked
2037 * @len: max length of the string to check
2038 */
2039bool audit_string_contains_control(const char *string, size_t len)
2040{
2041 const unsigned char *p;
2042 for (p = string; p < (const unsigned char *)string + len; p++) {
2043 if (*p == '"' || *p < 0x21 || *p > 0x7e)
2044 return true;
2045 }
2046 return false;
2047}
2048
2049/**
2050 * audit_log_n_untrustedstring - log a string that may contain random characters
2051 * @ab: audit_buffer
2052 * @len: length of string (not including trailing null)
2053 * @string: string to be logged
2054 *
2055 * This code will escape a string that is passed to it if the string
2056 * contains a control character, unprintable character, double quote mark,
2057 * or a space. Unescaped strings will start and end with a double quote mark.
2058 * Strings that are escaped are printed in hex (2 digits per char).
2059 *
2060 * The caller specifies the number of characters in the string to log, which may
2061 * or may not be the entire string.
2062 */
2063void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
2064 size_t len)
2065{
2066 if (audit_string_contains_control(string, len))
2067 audit_log_n_hex(ab, string, len);
2068 else
2069 audit_log_n_string(ab, string, len);
2070}
2071
2072/**
2073 * audit_log_untrustedstring - log a string that may contain random characters
2074 * @ab: audit_buffer
2075 * @string: string to be logged
2076 *
2077 * Same as audit_log_n_untrustedstring(), except that strlen is used to
2078 * determine string length.
2079 */
2080void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
2081{
2082 audit_log_n_untrustedstring(ab, string, strlen(string));
2083}
2084
2085/* This is a helper-function to print the escaped d_path */
2086void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
2087 const struct path *path)
2088{
2089 char *p, *pathname;
2090
2091 if (prefix)
2092 audit_log_format(ab, "%s", prefix);
2093
2094 /* We will allow 11 spaces for ' (deleted)' to be appended */
2095 pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
2096 if (!pathname) {
2097 audit_log_format(ab, "\"<no_memory>\"");
2098 return;
2099 }
2100 p = d_path(path, pathname, PATH_MAX+11);
2101 if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
2102 /* FIXME: can we save some information here? */
2103 audit_log_format(ab, "\"<too_long>\"");
2104 } else
2105 audit_log_untrustedstring(ab, p);
2106 kfree(pathname);
2107}
2108
2109void audit_log_session_info(struct audit_buffer *ab)
2110{
2111 unsigned int sessionid = audit_get_sessionid(current);
2112 uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
2113
2114 audit_log_format(ab, "auid=%u ses=%u", auid, sessionid);
2115}
2116
2117void audit_log_key(struct audit_buffer *ab, char *key)
2118{
2119 audit_log_format(ab, " key=");
2120 if (key)
2121 audit_log_untrustedstring(ab, key);
2122 else
2123 audit_log_format(ab, "(null)");
2124}
2125
2126int audit_log_task_context(struct audit_buffer *ab)
2127{
2128 char *ctx = NULL;
2129 unsigned len;
2130 int error;
2131 u32 sid;
2132
2133 security_task_getsecid(current, &sid);
2134 if (!sid)
2135 return 0;
2136
2137 error = security_secid_to_secctx(sid, &ctx, &len);
2138 if (error) {
2139 if (error != -EINVAL)
2140 goto error_path;
2141 return 0;
2142 }
2143
2144 audit_log_format(ab, " subj=%s", ctx);
2145 security_release_secctx(ctx, len);
2146 return 0;
2147
2148error_path:
2149 audit_panic("error in audit_log_task_context");
2150 return error;
2151}
2152EXPORT_SYMBOL(audit_log_task_context);
2153
2154void audit_log_d_path_exe(struct audit_buffer *ab,
2155 struct mm_struct *mm)
2156{
2157 struct file *exe_file;
2158
2159 if (!mm)
2160 goto out_null;
2161
2162 exe_file = get_mm_exe_file(mm);
2163 if (!exe_file)
2164 goto out_null;
2165
2166 audit_log_d_path(ab, " exe=", &exe_file->f_path);
2167 fput(exe_file);
2168 return;
2169out_null:
2170 audit_log_format(ab, " exe=(null)");
2171}
2172
2173struct tty_struct *audit_get_tty(void)
2174{
2175 struct tty_struct *tty = NULL;
2176 unsigned long flags;
2177
2178 spin_lock_irqsave(¤t->sighand->siglock, flags);
2179 if (current->signal)
2180 tty = tty_kref_get(current->signal->tty);
2181 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
2182 return tty;
2183}
2184
2185void audit_put_tty(struct tty_struct *tty)
2186{
2187 tty_kref_put(tty);
2188}
2189
2190void audit_log_task_info(struct audit_buffer *ab)
2191{
2192 const struct cred *cred;
2193 char comm[sizeof(current->comm)];
2194 struct tty_struct *tty;
2195
2196 if (!ab)
2197 return;
2198
2199 cred = current_cred();
2200 tty = audit_get_tty();
2201 audit_log_format(ab,
2202 " ppid=%d pid=%d auid=%u uid=%u gid=%u"
2203 " euid=%u suid=%u fsuid=%u"
2204 " egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
2205 task_ppid_nr(current),
2206 task_tgid_nr(current),
2207 from_kuid(&init_user_ns, audit_get_loginuid(current)),
2208 from_kuid(&init_user_ns, cred->uid),
2209 from_kgid(&init_user_ns, cred->gid),
2210 from_kuid(&init_user_ns, cred->euid),
2211 from_kuid(&init_user_ns, cred->suid),
2212 from_kuid(&init_user_ns, cred->fsuid),
2213 from_kgid(&init_user_ns, cred->egid),
2214 from_kgid(&init_user_ns, cred->sgid),
2215 from_kgid(&init_user_ns, cred->fsgid),
2216 tty ? tty_name(tty) : "(none)",
2217 audit_get_sessionid(current));
2218 audit_put_tty(tty);
2219 audit_log_format(ab, " comm=");
2220 audit_log_untrustedstring(ab, get_task_comm(comm, current));
2221 audit_log_d_path_exe(ab, current->mm);
2222 audit_log_task_context(ab);
2223}
2224EXPORT_SYMBOL(audit_log_task_info);
2225
2226/**
2227 * audit_log_path_denied - report a path restriction denial
2228 * @type: audit message type (AUDIT_ANOM_LINK, AUDIT_ANOM_CREAT, etc)
2229 * @operation: specific operation name
2230 */
2231void audit_log_path_denied(int type, const char *operation)
2232{
2233 struct audit_buffer *ab;
2234
2235 if (!audit_enabled || audit_dummy_context())
2236 return;
2237
2238 /* Generate log with subject, operation, outcome. */
2239 ab = audit_log_start(audit_context(), GFP_KERNEL, type);
2240 if (!ab)
2241 return;
2242 audit_log_format(ab, "op=%s", operation);
2243 audit_log_task_info(ab);
2244 audit_log_format(ab, " res=0");
2245 audit_log_end(ab);
2246}
2247
2248/* global counter which is incremented every time something logs in */
2249static atomic_t session_id = ATOMIC_INIT(0);
2250
2251static int audit_set_loginuid_perm(kuid_t loginuid)
2252{
2253 /* if we are unset, we don't need privs */
2254 if (!audit_loginuid_set(current))
2255 return 0;
2256 /* if AUDIT_FEATURE_LOGINUID_IMMUTABLE means never ever allow a change*/
2257 if (is_audit_feature_set(AUDIT_FEATURE_LOGINUID_IMMUTABLE))
2258 return -EPERM;
2259 /* it is set, you need permission */
2260 if (!capable(CAP_AUDIT_CONTROL))
2261 return -EPERM;
2262 /* reject if this is not an unset and we don't allow that */
2263 if (is_audit_feature_set(AUDIT_FEATURE_ONLY_UNSET_LOGINUID)
2264 && uid_valid(loginuid))
2265 return -EPERM;
2266 return 0;
2267}
2268
2269static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
2270 unsigned int oldsessionid,
2271 unsigned int sessionid, int rc)
2272{
2273 struct audit_buffer *ab;
2274 uid_t uid, oldloginuid, loginuid;
2275 struct tty_struct *tty;
2276
2277 if (!audit_enabled)
2278 return;
2279
2280 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_LOGIN);
2281 if (!ab)
2282 return;
2283
2284 uid = from_kuid(&init_user_ns, task_uid(current));
2285 oldloginuid = from_kuid(&init_user_ns, koldloginuid);
2286 loginuid = from_kuid(&init_user_ns, kloginuid),
2287 tty = audit_get_tty();
2288
2289 audit_log_format(ab, "pid=%d uid=%u", task_tgid_nr(current), uid);
2290 audit_log_task_context(ab);
2291 audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",
2292 oldloginuid, loginuid, tty ? tty_name(tty) : "(none)",
2293 oldsessionid, sessionid, !rc);
2294 audit_put_tty(tty);
2295 audit_log_end(ab);
2296}
2297
2298/**
2299 * audit_set_loginuid - set current task's loginuid
2300 * @loginuid: loginuid value
2301 *
2302 * Returns 0.
2303 *
2304 * Called (set) from fs/proc/base.c::proc_loginuid_write().
2305 */
2306int audit_set_loginuid(kuid_t loginuid)
2307{
2308 unsigned int oldsessionid, sessionid = AUDIT_SID_UNSET;
2309 kuid_t oldloginuid;
2310 int rc;
2311
2312 oldloginuid = audit_get_loginuid(current);
2313 oldsessionid = audit_get_sessionid(current);
2314
2315 rc = audit_set_loginuid_perm(loginuid);
2316 if (rc)
2317 goto out;
2318
2319 /* are we setting or clearing? */
2320 if (uid_valid(loginuid)) {
2321 sessionid = (unsigned int)atomic_inc_return(&session_id);
2322 if (unlikely(sessionid == AUDIT_SID_UNSET))
2323 sessionid = (unsigned int)atomic_inc_return(&session_id);
2324 }
2325
2326 current->sessionid = sessionid;
2327 current->loginuid = loginuid;
2328out:
2329 audit_log_set_loginuid(oldloginuid, loginuid, oldsessionid, sessionid, rc);
2330 return rc;
2331}
2332
2333/**
2334 * audit_signal_info - record signal info for shutting down audit subsystem
2335 * @sig: signal value
2336 * @t: task being signaled
2337 *
2338 * If the audit subsystem is being terminated, record the task (pid)
2339 * and uid that is doing that.
2340 */
2341int audit_signal_info(int sig, struct task_struct *t)
2342{
2343 kuid_t uid = current_uid(), auid;
2344
2345 if (auditd_test_task(t) &&
2346 (sig == SIGTERM || sig == SIGHUP ||
2347 sig == SIGUSR1 || sig == SIGUSR2)) {
2348 audit_sig_pid = task_tgid_nr(current);
2349 auid = audit_get_loginuid(current);
2350 if (uid_valid(auid))
2351 audit_sig_uid = auid;
2352 else
2353 audit_sig_uid = uid;
2354 security_task_getsecid(current, &audit_sig_sid);
2355 }
2356
2357 return audit_signal_info_syscall(t);
2358}
2359
2360/**
2361 * audit_log_end - end one audit record
2362 * @ab: the audit_buffer
2363 *
2364 * We can not do a netlink send inside an irq context because it blocks (last
2365 * arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a
2366 * queue and a tasklet is scheduled to remove them from the queue outside the
2367 * irq context. May be called in any context.
2368 */
2369void audit_log_end(struct audit_buffer *ab)
2370{
2371 struct sk_buff *skb;
2372 struct nlmsghdr *nlh;
2373
2374 if (!ab)
2375 return;
2376
2377 if (audit_rate_check()) {
2378 skb = ab->skb;
2379 ab->skb = NULL;
2380
2381 /* setup the netlink header, see the comments in
2382 * kauditd_send_multicast_skb() for length quirks */
2383 nlh = nlmsg_hdr(skb);
2384 nlh->nlmsg_len = skb->len - NLMSG_HDRLEN;
2385
2386 /* queue the netlink packet and poke the kauditd thread */
2387 skb_queue_tail(&audit_queue, skb);
2388 wake_up_interruptible(&kauditd_wait);
2389 } else
2390 audit_log_lost("rate limit exceeded");
2391
2392 audit_buffer_free(ab);
2393}
2394
2395/**
2396 * audit_log - Log an audit record
2397 * @ctx: audit context
2398 * @gfp_mask: type of allocation
2399 * @type: audit message type
2400 * @fmt: format string to use
2401 * @...: variable parameters matching the format string
2402 *
2403 * This is a convenience function that calls audit_log_start,
2404 * audit_log_vformat, and audit_log_end. It may be called
2405 * in any context.
2406 */
2407void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
2408 const char *fmt, ...)
2409{
2410 struct audit_buffer *ab;
2411 va_list args;
2412
2413 ab = audit_log_start(ctx, gfp_mask, type);
2414 if (ab) {
2415 va_start(args, fmt);
2416 audit_log_vformat(ab, fmt, args);
2417 va_end(args);
2418 audit_log_end(ab);
2419 }
2420}
2421
2422EXPORT_SYMBOL(audit_log_start);
2423EXPORT_SYMBOL(audit_log_end);
2424EXPORT_SYMBOL(audit_log_format);
2425EXPORT_SYMBOL(audit_log);