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