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1 | /* audit.c -- Auditing support | |
2 | * Gateway between the kernel (e.g., selinux) and the user-space audit daemon. | |
3 | * System-call specific features have moved to auditsc.c | |
4 | * | |
5 | * Copyright 2003-2007 Red Hat Inc., Durham, North Carolina. | |
6 | * All Rights Reserved. | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License as published by | |
10 | * the Free Software Foundation; either version 2 of the License, or | |
11 | * (at your option) any later version. | |
12 | * | |
13 | * This program is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | * GNU General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU General Public License | |
19 | * along with this program; if not, write to the Free Software | |
20 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
21 | * | |
22 | * Written by Rickard E. (Rik) Faith <faith@redhat.com> | |
23 | * | |
24 | * Goals: 1) Integrate fully with Security Modules. | |
25 | * 2) Minimal run-time overhead: | |
26 | * a) Minimal when syscall auditing is disabled (audit_enable=0). | |
27 | * b) Small when syscall auditing is enabled and no audit record | |
28 | * is generated (defer as much work as possible to record | |
29 | * generation time): | |
30 | * i) context is allocated, | |
31 | * ii) names from getname are stored without a copy, and | |
32 | * iii) inode information stored from path_lookup. | |
33 | * 3) Ability to disable syscall auditing at boot time (audit=0). | |
34 | * 4) Usable by other parts of the kernel (if audit_log* is called, | |
35 | * then a syscall record will be generated automatically for the | |
36 | * current syscall). | |
37 | * 5) Netlink interface to user-space. | |
38 | * 6) Support low-overhead kernel-based filtering to minimize the | |
39 | * information that must be passed to user-space. | |
40 | * | |
41 | * Example user-space utilities: http://people.redhat.com/sgrubb/audit/ | |
42 | */ | |
43 | ||
44 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
45 | ||
46 | #include <linux/file.h> | |
47 | #include <linux/init.h> | |
48 | #include <linux/types.h> | |
49 | #include <linux/atomic.h> | |
50 | #include <linux/mm.h> | |
51 | #include <linux/export.h> | |
52 | #include <linux/slab.h> | |
53 | #include <linux/err.h> | |
54 | #include <linux/kthread.h> | |
55 | #include <linux/kernel.h> | |
56 | #include <linux/syscalls.h> | |
57 | #include <linux/spinlock.h> | |
58 | #include <linux/rcupdate.h> | |
59 | #include <linux/mutex.h> | |
60 | #include <linux/gfp.h> | |
61 | #include <linux/pid.h> | |
62 | #include <linux/slab.h> | |
63 | ||
64 | #include <linux/audit.h> | |
65 | ||
66 | #include <net/sock.h> | |
67 | #include <net/netlink.h> | |
68 | #include <linux/skbuff.h> | |
69 | #ifdef CONFIG_SECURITY | |
70 | #include <linux/security.h> | |
71 | #endif | |
72 | #include <linux/freezer.h> | |
73 | #include <linux/pid_namespace.h> | |
74 | #include <net/netns/generic.h> | |
75 | ||
76 | #include "audit.h" | |
77 | ||
78 | /* No auditing will take place until audit_initialized == AUDIT_INITIALIZED. | |
79 | * (Initialization happens after skb_init is called.) */ | |
80 | #define AUDIT_DISABLED -1 | |
81 | #define AUDIT_UNINITIALIZED 0 | |
82 | #define AUDIT_INITIALIZED 1 | |
83 | static int audit_initialized; | |
84 | ||
85 | #define AUDIT_OFF 0 | |
86 | #define AUDIT_ON 1 | |
87 | #define AUDIT_LOCKED 2 | |
88 | u32 audit_enabled; | |
89 | u32 audit_ever_enabled; | |
90 | ||
91 | EXPORT_SYMBOL_GPL(audit_enabled); | |
92 | ||
93 | /* Default state when kernel boots without any parameters. */ | |
94 | static u32 audit_default; | |
95 | ||
96 | /* If auditing cannot proceed, audit_failure selects what happens. */ | |
97 | static u32 audit_failure = AUDIT_FAIL_PRINTK; | |
98 | ||
99 | /* private audit network namespace index */ | |
100 | static unsigned int audit_net_id; | |
101 | ||
102 | /** | |
103 | * struct audit_net - audit private network namespace data | |
104 | * @sk: communication socket | |
105 | */ | |
106 | struct audit_net { | |
107 | struct sock *sk; | |
108 | }; | |
109 | ||
110 | /** | |
111 | * struct auditd_connection - kernel/auditd connection state | |
112 | * @pid: auditd PID | |
113 | * @portid: netlink portid | |
114 | * @net: the associated network namespace | |
115 | * @rcu: RCU head | |
116 | * | |
117 | * Description: | |
118 | * This struct is RCU protected; you must either hold the RCU lock for reading | |
119 | * or the associated spinlock for writing. | |
120 | */ | |
121 | static struct auditd_connection { | |
122 | struct pid *pid; | |
123 | u32 portid; | |
124 | struct net *net; | |
125 | struct rcu_head rcu; | |
126 | } *auditd_conn = NULL; | |
127 | static DEFINE_SPINLOCK(auditd_conn_lock); | |
128 | ||
129 | /* If audit_rate_limit is non-zero, limit the rate of sending audit records | |
130 | * to that number per second. This prevents DoS attacks, but results in | |
131 | * audit records being dropped. */ | |
132 | static u32 audit_rate_limit; | |
133 | ||
134 | /* Number of outstanding audit_buffers allowed. | |
135 | * When set to zero, this means unlimited. */ | |
136 | static u32 audit_backlog_limit = 64; | |
137 | #define AUDIT_BACKLOG_WAIT_TIME (60 * HZ) | |
138 | static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME; | |
139 | ||
140 | /* The identity of the user shutting down the audit system. */ | |
141 | kuid_t audit_sig_uid = INVALID_UID; | |
142 | pid_t audit_sig_pid = -1; | |
143 | u32 audit_sig_sid = 0; | |
144 | ||
145 | /* Records can be lost in several ways: | |
146 | 0) [suppressed in audit_alloc] | |
147 | 1) out of memory in audit_log_start [kmalloc of struct audit_buffer] | |
148 | 2) out of memory in audit_log_move [alloc_skb] | |
149 | 3) suppressed due to audit_rate_limit | |
150 | 4) suppressed due to audit_backlog_limit | |
151 | */ | |
152 | static atomic_t audit_lost = ATOMIC_INIT(0); | |
153 | ||
154 | /* Hash for inode-based rules */ | |
155 | struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS]; | |
156 | ||
157 | static struct kmem_cache *audit_buffer_cache; | |
158 | ||
159 | /* queue msgs to send via kauditd_task */ | |
160 | static struct sk_buff_head audit_queue; | |
161 | /* queue msgs due to temporary unicast send problems */ | |
162 | static struct sk_buff_head audit_retry_queue; | |
163 | /* queue msgs waiting for new auditd connection */ | |
164 | static struct sk_buff_head audit_hold_queue; | |
165 | ||
166 | /* queue servicing thread */ | |
167 | static struct task_struct *kauditd_task; | |
168 | static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait); | |
169 | ||
170 | /* waitqueue for callers who are blocked on the audit backlog */ | |
171 | static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait); | |
172 | ||
173 | static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION, | |
174 | .mask = -1, | |
175 | .features = 0, | |
176 | .lock = 0,}; | |
177 | ||
178 | static char *audit_feature_names[2] = { | |
179 | "only_unset_loginuid", | |
180 | "loginuid_immutable", | |
181 | }; | |
182 | ||
183 | ||
184 | /* Serialize requests from userspace. */ | |
185 | DEFINE_MUTEX(audit_cmd_mutex); | |
186 | ||
187 | /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting | |
188 | * audit records. Since printk uses a 1024 byte buffer, this buffer | |
189 | * should be at least that large. */ | |
190 | #define AUDIT_BUFSIZ 1024 | |
191 | ||
192 | /* The audit_buffer is used when formatting an audit record. The caller | |
193 | * locks briefly to get the record off the freelist or to allocate the | |
194 | * buffer, and locks briefly to send the buffer to the netlink layer or | |
195 | * to place it on a transmit queue. Multiple audit_buffers can be in | |
196 | * use simultaneously. */ | |
197 | struct audit_buffer { | |
198 | struct sk_buff *skb; /* formatted skb ready to send */ | |
199 | struct audit_context *ctx; /* NULL or associated context */ | |
200 | gfp_t gfp_mask; | |
201 | }; | |
202 | ||
203 | struct audit_reply { | |
204 | __u32 portid; | |
205 | struct net *net; | |
206 | struct sk_buff *skb; | |
207 | }; | |
208 | ||
209 | /** | |
210 | * auditd_test_task - Check to see if a given task is an audit daemon | |
211 | * @task: the task to check | |
212 | * | |
213 | * Description: | |
214 | * Return 1 if the task is a registered audit daemon, 0 otherwise. | |
215 | */ | |
216 | int auditd_test_task(struct task_struct *task) | |
217 | { | |
218 | int rc; | |
219 | struct auditd_connection *ac; | |
220 | ||
221 | rcu_read_lock(); | |
222 | ac = rcu_dereference(auditd_conn); | |
223 | rc = (ac && ac->pid == task_tgid(task) ? 1 : 0); | |
224 | rcu_read_unlock(); | |
225 | ||
226 | return rc; | |
227 | } | |
228 | ||
229 | /** | |
230 | * auditd_pid_vnr - Return the auditd PID relative to the namespace | |
231 | * | |
232 | * Description: | |
233 | * Returns the PID in relation to the namespace, 0 on failure. | |
234 | */ | |
235 | static pid_t auditd_pid_vnr(void) | |
236 | { | |
237 | pid_t pid; | |
238 | const struct auditd_connection *ac; | |
239 | ||
240 | rcu_read_lock(); | |
241 | ac = rcu_dereference(auditd_conn); | |
242 | if (!ac || !ac->pid) | |
243 | pid = 0; | |
244 | else | |
245 | pid = pid_vnr(ac->pid); | |
246 | rcu_read_unlock(); | |
247 | ||
248 | return pid; | |
249 | } | |
250 | ||
251 | /** | |
252 | * audit_get_sk - Return the audit socket for the given network namespace | |
253 | * @net: the destination network namespace | |
254 | * | |
255 | * Description: | |
256 | * Returns the sock pointer if valid, NULL otherwise. The caller must ensure | |
257 | * that a reference is held for the network namespace while the sock is in use. | |
258 | */ | |
259 | static struct sock *audit_get_sk(const struct net *net) | |
260 | { | |
261 | struct audit_net *aunet; | |
262 | ||
263 | if (!net) | |
264 | return NULL; | |
265 | ||
266 | aunet = net_generic(net, audit_net_id); | |
267 | return aunet->sk; | |
268 | } | |
269 | ||
270 | void audit_panic(const char *message) | |
271 | { | |
272 | switch (audit_failure) { | |
273 | case AUDIT_FAIL_SILENT: | |
274 | break; | |
275 | case AUDIT_FAIL_PRINTK: | |
276 | if (printk_ratelimit()) | |
277 | pr_err("%s\n", message); | |
278 | break; | |
279 | case AUDIT_FAIL_PANIC: | |
280 | panic("audit: %s\n", message); | |
281 | break; | |
282 | } | |
283 | } | |
284 | ||
285 | static inline int audit_rate_check(void) | |
286 | { | |
287 | static unsigned long last_check = 0; | |
288 | static int messages = 0; | |
289 | static DEFINE_SPINLOCK(lock); | |
290 | unsigned long flags; | |
291 | unsigned long now; | |
292 | unsigned long elapsed; | |
293 | int retval = 0; | |
294 | ||
295 | if (!audit_rate_limit) return 1; | |
296 | ||
297 | spin_lock_irqsave(&lock, flags); | |
298 | if (++messages < audit_rate_limit) { | |
299 | retval = 1; | |
300 | } else { | |
301 | now = jiffies; | |
302 | elapsed = now - last_check; | |
303 | if (elapsed > HZ) { | |
304 | last_check = now; | |
305 | messages = 0; | |
306 | retval = 1; | |
307 | } | |
308 | } | |
309 | spin_unlock_irqrestore(&lock, flags); | |
310 | ||
311 | return retval; | |
312 | } | |
313 | ||
314 | /** | |
315 | * audit_log_lost - conditionally log lost audit message event | |
316 | * @message: the message stating reason for lost audit message | |
317 | * | |
318 | * Emit at least 1 message per second, even if audit_rate_check is | |
319 | * throttling. | |
320 | * Always increment the lost messages counter. | |
321 | */ | |
322 | void audit_log_lost(const char *message) | |
323 | { | |
324 | static unsigned long last_msg = 0; | |
325 | static DEFINE_SPINLOCK(lock); | |
326 | unsigned long flags; | |
327 | unsigned long now; | |
328 | int print; | |
329 | ||
330 | atomic_inc(&audit_lost); | |
331 | ||
332 | print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit); | |
333 | ||
334 | if (!print) { | |
335 | spin_lock_irqsave(&lock, flags); | |
336 | now = jiffies; | |
337 | if (now - last_msg > HZ) { | |
338 | print = 1; | |
339 | last_msg = now; | |
340 | } | |
341 | spin_unlock_irqrestore(&lock, flags); | |
342 | } | |
343 | ||
344 | if (print) { | |
345 | if (printk_ratelimit()) | |
346 | pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n", | |
347 | atomic_read(&audit_lost), | |
348 | audit_rate_limit, | |
349 | audit_backlog_limit); | |
350 | audit_panic(message); | |
351 | } | |
352 | } | |
353 | ||
354 | static int audit_log_config_change(char *function_name, u32 new, u32 old, | |
355 | int allow_changes) | |
356 | { | |
357 | struct audit_buffer *ab; | |
358 | int rc = 0; | |
359 | ||
360 | ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE); | |
361 | if (unlikely(!ab)) | |
362 | return rc; | |
363 | audit_log_format(ab, "%s=%u old=%u", function_name, new, old); | |
364 | audit_log_session_info(ab); | |
365 | rc = audit_log_task_context(ab); | |
366 | if (rc) | |
367 | allow_changes = 0; /* Something weird, deny request */ | |
368 | audit_log_format(ab, " res=%d", allow_changes); | |
369 | audit_log_end(ab); | |
370 | return rc; | |
371 | } | |
372 | ||
373 | static int audit_do_config_change(char *function_name, u32 *to_change, u32 new) | |
374 | { | |
375 | int allow_changes, rc = 0; | |
376 | u32 old = *to_change; | |
377 | ||
378 | /* check if we are locked */ | |
379 | if (audit_enabled == AUDIT_LOCKED) | |
380 | allow_changes = 0; | |
381 | else | |
382 | allow_changes = 1; | |
383 | ||
384 | if (audit_enabled != AUDIT_OFF) { | |
385 | rc = audit_log_config_change(function_name, new, old, allow_changes); | |
386 | if (rc) | |
387 | allow_changes = 0; | |
388 | } | |
389 | ||
390 | /* If we are allowed, make the change */ | |
391 | if (allow_changes == 1) | |
392 | *to_change = new; | |
393 | /* Not allowed, update reason */ | |
394 | else if (rc == 0) | |
395 | rc = -EPERM; | |
396 | return rc; | |
397 | } | |
398 | ||
399 | static int audit_set_rate_limit(u32 limit) | |
400 | { | |
401 | return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit); | |
402 | } | |
403 | ||
404 | static int audit_set_backlog_limit(u32 limit) | |
405 | { | |
406 | return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit); | |
407 | } | |
408 | ||
409 | static int audit_set_backlog_wait_time(u32 timeout) | |
410 | { | |
411 | return audit_do_config_change("audit_backlog_wait_time", | |
412 | &audit_backlog_wait_time, timeout); | |
413 | } | |
414 | ||
415 | static int audit_set_enabled(u32 state) | |
416 | { | |
417 | int rc; | |
418 | if (state > AUDIT_LOCKED) | |
419 | return -EINVAL; | |
420 | ||
421 | rc = audit_do_config_change("audit_enabled", &audit_enabled, state); | |
422 | if (!rc) | |
423 | audit_ever_enabled |= !!state; | |
424 | ||
425 | return rc; | |
426 | } | |
427 | ||
428 | static int audit_set_failure(u32 state) | |
429 | { | |
430 | if (state != AUDIT_FAIL_SILENT | |
431 | && state != AUDIT_FAIL_PRINTK | |
432 | && state != AUDIT_FAIL_PANIC) | |
433 | return -EINVAL; | |
434 | ||
435 | return audit_do_config_change("audit_failure", &audit_failure, state); | |
436 | } | |
437 | ||
438 | /** | |
439 | * auditd_conn_free - RCU helper to release an auditd connection struct | |
440 | * @rcu: RCU head | |
441 | * | |
442 | * Description: | |
443 | * Drop any references inside the auditd connection tracking struct and free | |
444 | * the memory. | |
445 | */ | |
446 | static void auditd_conn_free(struct rcu_head *rcu) | |
447 | { | |
448 | struct auditd_connection *ac; | |
449 | ||
450 | ac = container_of(rcu, struct auditd_connection, rcu); | |
451 | put_pid(ac->pid); | |
452 | put_net(ac->net); | |
453 | kfree(ac); | |
454 | } | |
455 | ||
456 | /** | |
457 | * auditd_set - Set/Reset the auditd connection state | |
458 | * @pid: auditd PID | |
459 | * @portid: auditd netlink portid | |
460 | * @net: auditd network namespace pointer | |
461 | * | |
462 | * Description: | |
463 | * This function will obtain and drop network namespace references as | |
464 | * necessary. Returns zero on success, negative values on failure. | |
465 | */ | |
466 | static int auditd_set(struct pid *pid, u32 portid, struct net *net) | |
467 | { | |
468 | unsigned long flags; | |
469 | struct auditd_connection *ac_old, *ac_new; | |
470 | ||
471 | if (!pid || !net) | |
472 | return -EINVAL; | |
473 | ||
474 | ac_new = kzalloc(sizeof(*ac_new), GFP_KERNEL); | |
475 | if (!ac_new) | |
476 | return -ENOMEM; | |
477 | ac_new->pid = get_pid(pid); | |
478 | ac_new->portid = portid; | |
479 | ac_new->net = get_net(net); | |
480 | ||
481 | spin_lock_irqsave(&auditd_conn_lock, flags); | |
482 | ac_old = rcu_dereference_protected(auditd_conn, | |
483 | lockdep_is_held(&auditd_conn_lock)); | |
484 | rcu_assign_pointer(auditd_conn, ac_new); | |
485 | spin_unlock_irqrestore(&auditd_conn_lock, flags); | |
486 | ||
487 | if (ac_old) | |
488 | call_rcu(&ac_old->rcu, auditd_conn_free); | |
489 | ||
490 | return 0; | |
491 | } | |
492 | ||
493 | /** | |
494 | * kauditd_print_skb - Print the audit record to the ring buffer | |
495 | * @skb: audit record | |
496 | * | |
497 | * Whatever the reason, this packet may not make it to the auditd connection | |
498 | * so write it via printk so the information isn't completely lost. | |
499 | */ | |
500 | static void kauditd_printk_skb(struct sk_buff *skb) | |
501 | { | |
502 | struct nlmsghdr *nlh = nlmsg_hdr(skb); | |
503 | char *data = nlmsg_data(nlh); | |
504 | ||
505 | if (nlh->nlmsg_type != AUDIT_EOE && printk_ratelimit()) | |
506 | pr_notice("type=%d %s\n", nlh->nlmsg_type, data); | |
507 | } | |
508 | ||
509 | /** | |
510 | * kauditd_rehold_skb - Handle a audit record send failure in the hold queue | |
511 | * @skb: audit record | |
512 | * | |
513 | * Description: | |
514 | * This should only be used by the kauditd_thread when it fails to flush the | |
515 | * hold queue. | |
516 | */ | |
517 | static void kauditd_rehold_skb(struct sk_buff *skb) | |
518 | { | |
519 | /* put the record back in the queue at the same place */ | |
520 | skb_queue_head(&audit_hold_queue, skb); | |
521 | } | |
522 | ||
523 | /** | |
524 | * kauditd_hold_skb - Queue an audit record, waiting for auditd | |
525 | * @skb: audit record | |
526 | * | |
527 | * Description: | |
528 | * Queue the audit record, waiting for an instance of auditd. When this | |
529 | * function is called we haven't given up yet on sending the record, but things | |
530 | * are not looking good. The first thing we want to do is try to write the | |
531 | * record via printk and then see if we want to try and hold on to the record | |
532 | * and queue it, if we have room. If we want to hold on to the record, but we | |
533 | * don't have room, record a record lost message. | |
534 | */ | |
535 | static void kauditd_hold_skb(struct sk_buff *skb) | |
536 | { | |
537 | /* at this point it is uncertain if we will ever send this to auditd so | |
538 | * try to send the message via printk before we go any further */ | |
539 | kauditd_printk_skb(skb); | |
540 | ||
541 | /* can we just silently drop the message? */ | |
542 | if (!audit_default) { | |
543 | kfree_skb(skb); | |
544 | return; | |
545 | } | |
546 | ||
547 | /* if we have room, queue the message */ | |
548 | if (!audit_backlog_limit || | |
549 | skb_queue_len(&audit_hold_queue) < audit_backlog_limit) { | |
550 | skb_queue_tail(&audit_hold_queue, skb); | |
551 | return; | |
552 | } | |
553 | ||
554 | /* we have no other options - drop the message */ | |
555 | audit_log_lost("kauditd hold queue overflow"); | |
556 | kfree_skb(skb); | |
557 | } | |
558 | ||
559 | /** | |
560 | * kauditd_retry_skb - Queue an audit record, attempt to send again to auditd | |
561 | * @skb: audit record | |
562 | * | |
563 | * Description: | |
564 | * Not as serious as kauditd_hold_skb() as we still have a connected auditd, | |
565 | * but for some reason we are having problems sending it audit records so | |
566 | * queue the given record and attempt to resend. | |
567 | */ | |
568 | static void kauditd_retry_skb(struct sk_buff *skb) | |
569 | { | |
570 | /* NOTE: because records should only live in the retry queue for a | |
571 | * short period of time, before either being sent or moved to the hold | |
572 | * queue, we don't currently enforce a limit on this queue */ | |
573 | skb_queue_tail(&audit_retry_queue, skb); | |
574 | } | |
575 | ||
576 | /** | |
577 | * auditd_reset - Disconnect the auditd connection | |
578 | * @ac: auditd connection state | |
579 | * | |
580 | * Description: | |
581 | * Break the auditd/kauditd connection and move all the queued records into the | |
582 | * hold queue in case auditd reconnects. It is important to note that the @ac | |
583 | * pointer should never be dereferenced inside this function as it may be NULL | |
584 | * or invalid, you can only compare the memory address! If @ac is NULL then | |
585 | * the connection will always be reset. | |
586 | */ | |
587 | static void auditd_reset(const struct auditd_connection *ac) | |
588 | { | |
589 | unsigned long flags; | |
590 | struct sk_buff *skb; | |
591 | struct auditd_connection *ac_old; | |
592 | ||
593 | /* if it isn't already broken, break the connection */ | |
594 | spin_lock_irqsave(&auditd_conn_lock, flags); | |
595 | ac_old = rcu_dereference_protected(auditd_conn, | |
596 | lockdep_is_held(&auditd_conn_lock)); | |
597 | if (ac && ac != ac_old) { | |
598 | /* someone already registered a new auditd connection */ | |
599 | spin_unlock_irqrestore(&auditd_conn_lock, flags); | |
600 | return; | |
601 | } | |
602 | rcu_assign_pointer(auditd_conn, NULL); | |
603 | spin_unlock_irqrestore(&auditd_conn_lock, flags); | |
604 | ||
605 | if (ac_old) | |
606 | call_rcu(&ac_old->rcu, auditd_conn_free); | |
607 | ||
608 | /* flush the retry queue to the hold queue, but don't touch the main | |
609 | * queue since we need to process that normally for multicast */ | |
610 | while ((skb = skb_dequeue(&audit_retry_queue))) | |
611 | kauditd_hold_skb(skb); | |
612 | } | |
613 | ||
614 | /** | |
615 | * auditd_send_unicast_skb - Send a record via unicast to auditd | |
616 | * @skb: audit record | |
617 | * | |
618 | * Description: | |
619 | * Send a skb to the audit daemon, returns positive/zero values on success and | |
620 | * negative values on failure; in all cases the skb will be consumed by this | |
621 | * function. If the send results in -ECONNREFUSED the connection with auditd | |
622 | * will be reset. This function may sleep so callers should not hold any locks | |
623 | * where this would cause a problem. | |
624 | */ | |
625 | static int auditd_send_unicast_skb(struct sk_buff *skb) | |
626 | { | |
627 | int rc; | |
628 | u32 portid; | |
629 | struct net *net; | |
630 | struct sock *sk; | |
631 | struct auditd_connection *ac; | |
632 | ||
633 | /* NOTE: we can't call netlink_unicast while in the RCU section so | |
634 | * take a reference to the network namespace and grab local | |
635 | * copies of the namespace, the sock, and the portid; the | |
636 | * namespace and sock aren't going to go away while we hold a | |
637 | * reference and if the portid does become invalid after the RCU | |
638 | * section netlink_unicast() should safely return an error */ | |
639 | ||
640 | rcu_read_lock(); | |
641 | ac = rcu_dereference(auditd_conn); | |
642 | if (!ac) { | |
643 | rcu_read_unlock(); | |
644 | kfree_skb(skb); | |
645 | rc = -ECONNREFUSED; | |
646 | goto err; | |
647 | } | |
648 | net = get_net(ac->net); | |
649 | sk = audit_get_sk(net); | |
650 | portid = ac->portid; | |
651 | rcu_read_unlock(); | |
652 | ||
653 | rc = netlink_unicast(sk, skb, portid, 0); | |
654 | put_net(net); | |
655 | if (rc < 0) | |
656 | goto err; | |
657 | ||
658 | return rc; | |
659 | ||
660 | err: | |
661 | if (ac && rc == -ECONNREFUSED) | |
662 | auditd_reset(ac); | |
663 | return rc; | |
664 | } | |
665 | ||
666 | /** | |
667 | * kauditd_send_queue - Helper for kauditd_thread to flush skb queues | |
668 | * @sk: the sending sock | |
669 | * @portid: the netlink destination | |
670 | * @queue: the skb queue to process | |
671 | * @retry_limit: limit on number of netlink unicast failures | |
672 | * @skb_hook: per-skb hook for additional processing | |
673 | * @err_hook: hook called if the skb fails the netlink unicast send | |
674 | * | |
675 | * Description: | |
676 | * Run through the given queue and attempt to send the audit records to auditd, | |
677 | * returns zero on success, negative values on failure. It is up to the caller | |
678 | * to ensure that the @sk is valid for the duration of this function. | |
679 | * | |
680 | */ | |
681 | static int kauditd_send_queue(struct sock *sk, u32 portid, | |
682 | struct sk_buff_head *queue, | |
683 | unsigned int retry_limit, | |
684 | void (*skb_hook)(struct sk_buff *skb), | |
685 | void (*err_hook)(struct sk_buff *skb)) | |
686 | { | |
687 | int rc = 0; | |
688 | struct sk_buff *skb; | |
689 | static unsigned int failed = 0; | |
690 | ||
691 | /* NOTE: kauditd_thread takes care of all our locking, we just use | |
692 | * the netlink info passed to us (e.g. sk and portid) */ | |
693 | ||
694 | while ((skb = skb_dequeue(queue))) { | |
695 | /* call the skb_hook for each skb we touch */ | |
696 | if (skb_hook) | |
697 | (*skb_hook)(skb); | |
698 | ||
699 | /* can we send to anyone via unicast? */ | |
700 | if (!sk) { | |
701 | if (err_hook) | |
702 | (*err_hook)(skb); | |
703 | continue; | |
704 | } | |
705 | ||
706 | /* grab an extra skb reference in case of error */ | |
707 | skb_get(skb); | |
708 | rc = netlink_unicast(sk, skb, portid, 0); | |
709 | if (rc < 0) { | |
710 | /* fatal failure for our queue flush attempt? */ | |
711 | if (++failed >= retry_limit || | |
712 | rc == -ECONNREFUSED || rc == -EPERM) { | |
713 | /* yes - error processing for the queue */ | |
714 | sk = NULL; | |
715 | if (err_hook) | |
716 | (*err_hook)(skb); | |
717 | if (!skb_hook) | |
718 | goto out; | |
719 | /* keep processing with the skb_hook */ | |
720 | continue; | |
721 | } else | |
722 | /* no - requeue to preserve ordering */ | |
723 | skb_queue_head(queue, skb); | |
724 | } else { | |
725 | /* it worked - drop the extra reference and continue */ | |
726 | consume_skb(skb); | |
727 | failed = 0; | |
728 | } | |
729 | } | |
730 | ||
731 | out: | |
732 | return (rc >= 0 ? 0 : rc); | |
733 | } | |
734 | ||
735 | /* | |
736 | * kauditd_send_multicast_skb - Send a record to any multicast listeners | |
737 | * @skb: audit record | |
738 | * | |
739 | * Description: | |
740 | * Write a multicast message to anyone listening in the initial network | |
741 | * namespace. This function doesn't consume an skb as might be expected since | |
742 | * it has to copy it anyways. | |
743 | */ | |
744 | static void kauditd_send_multicast_skb(struct sk_buff *skb) | |
745 | { | |
746 | struct sk_buff *copy; | |
747 | struct sock *sock = audit_get_sk(&init_net); | |
748 | struct nlmsghdr *nlh; | |
749 | ||
750 | /* NOTE: we are not taking an additional reference for init_net since | |
751 | * we don't have to worry about it going away */ | |
752 | ||
753 | if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG)) | |
754 | return; | |
755 | ||
756 | /* | |
757 | * The seemingly wasteful skb_copy() rather than bumping the refcount | |
758 | * using skb_get() is necessary because non-standard mods are made to | |
759 | * the skb by the original kaudit unicast socket send routine. The | |
760 | * existing auditd daemon assumes this breakage. Fixing this would | |
761 | * require co-ordinating a change in the established protocol between | |
762 | * the kaudit kernel subsystem and the auditd userspace code. There is | |
763 | * no reason for new multicast clients to continue with this | |
764 | * non-compliance. | |
765 | */ | |
766 | copy = skb_copy(skb, GFP_KERNEL); | |
767 | if (!copy) | |
768 | return; | |
769 | nlh = nlmsg_hdr(copy); | |
770 | nlh->nlmsg_len = skb->len; | |
771 | ||
772 | nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL); | |
773 | } | |
774 | ||
775 | /** | |
776 | * kauditd_thread - Worker thread to send audit records to userspace | |
777 | * @dummy: unused | |
778 | */ | |
779 | static int kauditd_thread(void *dummy) | |
780 | { | |
781 | int rc; | |
782 | u32 portid = 0; | |
783 | struct net *net = NULL; | |
784 | struct sock *sk = NULL; | |
785 | struct auditd_connection *ac; | |
786 | ||
787 | #define UNICAST_RETRIES 5 | |
788 | ||
789 | set_freezable(); | |
790 | while (!kthread_should_stop()) { | |
791 | /* NOTE: see the lock comments in auditd_send_unicast_skb() */ | |
792 | rcu_read_lock(); | |
793 | ac = rcu_dereference(auditd_conn); | |
794 | if (!ac) { | |
795 | rcu_read_unlock(); | |
796 | goto main_queue; | |
797 | } | |
798 | net = get_net(ac->net); | |
799 | sk = audit_get_sk(net); | |
800 | portid = ac->portid; | |
801 | rcu_read_unlock(); | |
802 | ||
803 | /* attempt to flush the hold queue */ | |
804 | rc = kauditd_send_queue(sk, portid, | |
805 | &audit_hold_queue, UNICAST_RETRIES, | |
806 | NULL, kauditd_rehold_skb); | |
807 | if (ac && rc < 0) { | |
808 | sk = NULL; | |
809 | auditd_reset(ac); | |
810 | goto main_queue; | |
811 | } | |
812 | ||
813 | /* attempt to flush the retry queue */ | |
814 | rc = kauditd_send_queue(sk, portid, | |
815 | &audit_retry_queue, UNICAST_RETRIES, | |
816 | NULL, kauditd_hold_skb); | |
817 | if (ac && rc < 0) { | |
818 | sk = NULL; | |
819 | auditd_reset(ac); | |
820 | goto main_queue; | |
821 | } | |
822 | ||
823 | main_queue: | |
824 | /* process the main queue - do the multicast send and attempt | |
825 | * unicast, dump failed record sends to the retry queue; if | |
826 | * sk == NULL due to previous failures we will just do the | |
827 | * multicast send and move the record to the hold queue */ | |
828 | rc = kauditd_send_queue(sk, portid, &audit_queue, 1, | |
829 | kauditd_send_multicast_skb, | |
830 | (sk ? | |
831 | kauditd_retry_skb : kauditd_hold_skb)); | |
832 | if (ac && rc < 0) | |
833 | auditd_reset(ac); | |
834 | sk = NULL; | |
835 | ||
836 | /* drop our netns reference, no auditd sends past this line */ | |
837 | if (net) { | |
838 | put_net(net); | |
839 | net = NULL; | |
840 | } | |
841 | ||
842 | /* we have processed all the queues so wake everyone */ | |
843 | wake_up(&audit_backlog_wait); | |
844 | ||
845 | /* NOTE: we want to wake up if there is anything on the queue, | |
846 | * regardless of if an auditd is connected, as we need to | |
847 | * do the multicast send and rotate records from the | |
848 | * main queue to the retry/hold queues */ | |
849 | wait_event_freezable(kauditd_wait, | |
850 | (skb_queue_len(&audit_queue) ? 1 : 0)); | |
851 | } | |
852 | ||
853 | return 0; | |
854 | } | |
855 | ||
856 | int audit_send_list(void *_dest) | |
857 | { | |
858 | struct audit_netlink_list *dest = _dest; | |
859 | struct sk_buff *skb; | |
860 | struct sock *sk = audit_get_sk(dest->net); | |
861 | ||
862 | /* wait for parent to finish and send an ACK */ | |
863 | mutex_lock(&audit_cmd_mutex); | |
864 | mutex_unlock(&audit_cmd_mutex); | |
865 | ||
866 | while ((skb = __skb_dequeue(&dest->q)) != NULL) | |
867 | netlink_unicast(sk, skb, dest->portid, 0); | |
868 | ||
869 | put_net(dest->net); | |
870 | kfree(dest); | |
871 | ||
872 | return 0; | |
873 | } | |
874 | ||
875 | struct sk_buff *audit_make_reply(int seq, int type, int done, | |
876 | int multi, const void *payload, int size) | |
877 | { | |
878 | struct sk_buff *skb; | |
879 | struct nlmsghdr *nlh; | |
880 | void *data; | |
881 | int flags = multi ? NLM_F_MULTI : 0; | |
882 | int t = done ? NLMSG_DONE : type; | |
883 | ||
884 | skb = nlmsg_new(size, GFP_KERNEL); | |
885 | if (!skb) | |
886 | return NULL; | |
887 | ||
888 | nlh = nlmsg_put(skb, 0, seq, t, size, flags); | |
889 | if (!nlh) | |
890 | goto out_kfree_skb; | |
891 | data = nlmsg_data(nlh); | |
892 | memcpy(data, payload, size); | |
893 | return skb; | |
894 | ||
895 | out_kfree_skb: | |
896 | kfree_skb(skb); | |
897 | return NULL; | |
898 | } | |
899 | ||
900 | static int audit_send_reply_thread(void *arg) | |
901 | { | |
902 | struct audit_reply *reply = (struct audit_reply *)arg; | |
903 | struct sock *sk = audit_get_sk(reply->net); | |
904 | ||
905 | mutex_lock(&audit_cmd_mutex); | |
906 | mutex_unlock(&audit_cmd_mutex); | |
907 | ||
908 | /* Ignore failure. It'll only happen if the sender goes away, | |
909 | because our timeout is set to infinite. */ | |
910 | netlink_unicast(sk, reply->skb, reply->portid, 0); | |
911 | put_net(reply->net); | |
912 | kfree(reply); | |
913 | return 0; | |
914 | } | |
915 | ||
916 | /** | |
917 | * audit_send_reply - send an audit reply message via netlink | |
918 | * @request_skb: skb of request we are replying to (used to target the reply) | |
919 | * @seq: sequence number | |
920 | * @type: audit message type | |
921 | * @done: done (last) flag | |
922 | * @multi: multi-part message flag | |
923 | * @payload: payload data | |
924 | * @size: payload size | |
925 | * | |
926 | * Allocates an skb, builds the netlink message, and sends it to the port id. | |
927 | * No failure notifications. | |
928 | */ | |
929 | static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done, | |
930 | int multi, const void *payload, int size) | |
931 | { | |
932 | struct net *net = sock_net(NETLINK_CB(request_skb).sk); | |
933 | struct sk_buff *skb; | |
934 | struct task_struct *tsk; | |
935 | struct audit_reply *reply = kmalloc(sizeof(struct audit_reply), | |
936 | GFP_KERNEL); | |
937 | ||
938 | if (!reply) | |
939 | return; | |
940 | ||
941 | skb = audit_make_reply(seq, type, done, multi, payload, size); | |
942 | if (!skb) | |
943 | goto out; | |
944 | ||
945 | reply->net = get_net(net); | |
946 | reply->portid = NETLINK_CB(request_skb).portid; | |
947 | reply->skb = skb; | |
948 | ||
949 | tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply"); | |
950 | if (!IS_ERR(tsk)) | |
951 | return; | |
952 | kfree_skb(skb); | |
953 | out: | |
954 | kfree(reply); | |
955 | } | |
956 | ||
957 | /* | |
958 | * Check for appropriate CAP_AUDIT_ capabilities on incoming audit | |
959 | * control messages. | |
960 | */ | |
961 | static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type) | |
962 | { | |
963 | int err = 0; | |
964 | ||
965 | /* Only support initial user namespace for now. */ | |
966 | /* | |
967 | * We return ECONNREFUSED because it tricks userspace into thinking | |
968 | * that audit was not configured into the kernel. Lots of users | |
969 | * configure their PAM stack (because that's what the distro does) | |
970 | * to reject login if unable to send messages to audit. If we return | |
971 | * ECONNREFUSED the PAM stack thinks the kernel does not have audit | |
972 | * configured in and will let login proceed. If we return EPERM | |
973 | * userspace will reject all logins. This should be removed when we | |
974 | * support non init namespaces!! | |
975 | */ | |
976 | if (current_user_ns() != &init_user_ns) | |
977 | return -ECONNREFUSED; | |
978 | ||
979 | switch (msg_type) { | |
980 | case AUDIT_LIST: | |
981 | case AUDIT_ADD: | |
982 | case AUDIT_DEL: | |
983 | return -EOPNOTSUPP; | |
984 | case AUDIT_GET: | |
985 | case AUDIT_SET: | |
986 | case AUDIT_GET_FEATURE: | |
987 | case AUDIT_SET_FEATURE: | |
988 | case AUDIT_LIST_RULES: | |
989 | case AUDIT_ADD_RULE: | |
990 | case AUDIT_DEL_RULE: | |
991 | case AUDIT_SIGNAL_INFO: | |
992 | case AUDIT_TTY_GET: | |
993 | case AUDIT_TTY_SET: | |
994 | case AUDIT_TRIM: | |
995 | case AUDIT_MAKE_EQUIV: | |
996 | /* Only support auditd and auditctl in initial pid namespace | |
997 | * for now. */ | |
998 | if (task_active_pid_ns(current) != &init_pid_ns) | |
999 | return -EPERM; | |
1000 | ||
1001 | if (!netlink_capable(skb, CAP_AUDIT_CONTROL)) | |
1002 | err = -EPERM; | |
1003 | break; | |
1004 | case AUDIT_USER: | |
1005 | case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG: | |
1006 | case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2: | |
1007 | if (!netlink_capable(skb, CAP_AUDIT_WRITE)) | |
1008 | err = -EPERM; | |
1009 | break; | |
1010 | default: /* bad msg */ | |
1011 | err = -EINVAL; | |
1012 | } | |
1013 | ||
1014 | return err; | |
1015 | } | |
1016 | ||
1017 | static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type) | |
1018 | { | |
1019 | uid_t uid = from_kuid(&init_user_ns, current_uid()); | |
1020 | pid_t pid = task_tgid_nr(current); | |
1021 | ||
1022 | if (!audit_enabled && msg_type != AUDIT_USER_AVC) { | |
1023 | *ab = NULL; | |
1024 | return; | |
1025 | } | |
1026 | ||
1027 | *ab = audit_log_start(NULL, GFP_KERNEL, msg_type); | |
1028 | if (unlikely(!*ab)) | |
1029 | return; | |
1030 | audit_log_format(*ab, "pid=%d uid=%u", pid, uid); | |
1031 | audit_log_session_info(*ab); | |
1032 | audit_log_task_context(*ab); | |
1033 | } | |
1034 | ||
1035 | int is_audit_feature_set(int i) | |
1036 | { | |
1037 | return af.features & AUDIT_FEATURE_TO_MASK(i); | |
1038 | } | |
1039 | ||
1040 | ||
1041 | static int audit_get_feature(struct sk_buff *skb) | |
1042 | { | |
1043 | u32 seq; | |
1044 | ||
1045 | seq = nlmsg_hdr(skb)->nlmsg_seq; | |
1046 | ||
1047 | audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af)); | |
1048 | ||
1049 | return 0; | |
1050 | } | |
1051 | ||
1052 | static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature, | |
1053 | u32 old_lock, u32 new_lock, int res) | |
1054 | { | |
1055 | struct audit_buffer *ab; | |
1056 | ||
1057 | if (audit_enabled == AUDIT_OFF) | |
1058 | return; | |
1059 | ||
1060 | ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_FEATURE_CHANGE); | |
1061 | audit_log_task_info(ab, current); | |
1062 | audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d", | |
1063 | audit_feature_names[which], !!old_feature, !!new_feature, | |
1064 | !!old_lock, !!new_lock, res); | |
1065 | audit_log_end(ab); | |
1066 | } | |
1067 | ||
1068 | static int audit_set_feature(struct sk_buff *skb) | |
1069 | { | |
1070 | struct audit_features *uaf; | |
1071 | int i; | |
1072 | ||
1073 | BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names)); | |
1074 | uaf = nlmsg_data(nlmsg_hdr(skb)); | |
1075 | ||
1076 | /* if there is ever a version 2 we should handle that here */ | |
1077 | ||
1078 | for (i = 0; i <= AUDIT_LAST_FEATURE; i++) { | |
1079 | u32 feature = AUDIT_FEATURE_TO_MASK(i); | |
1080 | u32 old_feature, new_feature, old_lock, new_lock; | |
1081 | ||
1082 | /* if we are not changing this feature, move along */ | |
1083 | if (!(feature & uaf->mask)) | |
1084 | continue; | |
1085 | ||
1086 | old_feature = af.features & feature; | |
1087 | new_feature = uaf->features & feature; | |
1088 | new_lock = (uaf->lock | af.lock) & feature; | |
1089 | old_lock = af.lock & feature; | |
1090 | ||
1091 | /* are we changing a locked feature? */ | |
1092 | if (old_lock && (new_feature != old_feature)) { | |
1093 | audit_log_feature_change(i, old_feature, new_feature, | |
1094 | old_lock, new_lock, 0); | |
1095 | return -EPERM; | |
1096 | } | |
1097 | } | |
1098 | /* nothing invalid, do the changes */ | |
1099 | for (i = 0; i <= AUDIT_LAST_FEATURE; i++) { | |
1100 | u32 feature = AUDIT_FEATURE_TO_MASK(i); | |
1101 | u32 old_feature, new_feature, old_lock, new_lock; | |
1102 | ||
1103 | /* if we are not changing this feature, move along */ | |
1104 | if (!(feature & uaf->mask)) | |
1105 | continue; | |
1106 | ||
1107 | old_feature = af.features & feature; | |
1108 | new_feature = uaf->features & feature; | |
1109 | old_lock = af.lock & feature; | |
1110 | new_lock = (uaf->lock | af.lock) & feature; | |
1111 | ||
1112 | if (new_feature != old_feature) | |
1113 | audit_log_feature_change(i, old_feature, new_feature, | |
1114 | old_lock, new_lock, 1); | |
1115 | ||
1116 | if (new_feature) | |
1117 | af.features |= feature; | |
1118 | else | |
1119 | af.features &= ~feature; | |
1120 | af.lock |= new_lock; | |
1121 | } | |
1122 | ||
1123 | return 0; | |
1124 | } | |
1125 | ||
1126 | static int audit_replace(struct pid *pid) | |
1127 | { | |
1128 | pid_t pvnr; | |
1129 | struct sk_buff *skb; | |
1130 | ||
1131 | pvnr = pid_vnr(pid); | |
1132 | skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pvnr, sizeof(pvnr)); | |
1133 | if (!skb) | |
1134 | return -ENOMEM; | |
1135 | return auditd_send_unicast_skb(skb); | |
1136 | } | |
1137 | ||
1138 | static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) | |
1139 | { | |
1140 | u32 seq; | |
1141 | void *data; | |
1142 | int err; | |
1143 | struct audit_buffer *ab; | |
1144 | u16 msg_type = nlh->nlmsg_type; | |
1145 | struct audit_sig_info *sig_data; | |
1146 | char *ctx = NULL; | |
1147 | u32 len; | |
1148 | ||
1149 | err = audit_netlink_ok(skb, msg_type); | |
1150 | if (err) | |
1151 | return err; | |
1152 | ||
1153 | seq = nlh->nlmsg_seq; | |
1154 | data = nlmsg_data(nlh); | |
1155 | ||
1156 | switch (msg_type) { | |
1157 | case AUDIT_GET: { | |
1158 | struct audit_status s; | |
1159 | memset(&s, 0, sizeof(s)); | |
1160 | s.enabled = audit_enabled; | |
1161 | s.failure = audit_failure; | |
1162 | /* NOTE: use pid_vnr() so the PID is relative to the current | |
1163 | * namespace */ | |
1164 | s.pid = auditd_pid_vnr(); | |
1165 | s.rate_limit = audit_rate_limit; | |
1166 | s.backlog_limit = audit_backlog_limit; | |
1167 | s.lost = atomic_read(&audit_lost); | |
1168 | s.backlog = skb_queue_len(&audit_queue); | |
1169 | s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL; | |
1170 | s.backlog_wait_time = audit_backlog_wait_time; | |
1171 | audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s)); | |
1172 | break; | |
1173 | } | |
1174 | case AUDIT_SET: { | |
1175 | struct audit_status s; | |
1176 | memset(&s, 0, sizeof(s)); | |
1177 | /* guard against past and future API changes */ | |
1178 | memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh))); | |
1179 | if (s.mask & AUDIT_STATUS_ENABLED) { | |
1180 | err = audit_set_enabled(s.enabled); | |
1181 | if (err < 0) | |
1182 | return err; | |
1183 | } | |
1184 | if (s.mask & AUDIT_STATUS_FAILURE) { | |
1185 | err = audit_set_failure(s.failure); | |
1186 | if (err < 0) | |
1187 | return err; | |
1188 | } | |
1189 | if (s.mask & AUDIT_STATUS_PID) { | |
1190 | /* NOTE: we are using the vnr PID functions below | |
1191 | * because the s.pid value is relative to the | |
1192 | * namespace of the caller; at present this | |
1193 | * doesn't matter much since you can really only | |
1194 | * run auditd from the initial pid namespace, but | |
1195 | * something to keep in mind if this changes */ | |
1196 | pid_t new_pid = s.pid; | |
1197 | pid_t auditd_pid; | |
1198 | struct pid *req_pid = task_tgid(current); | |
1199 | ||
1200 | /* sanity check - PID values must match */ | |
1201 | if (new_pid != pid_vnr(req_pid)) | |
1202 | return -EINVAL; | |
1203 | ||
1204 | /* test the auditd connection */ | |
1205 | audit_replace(req_pid); | |
1206 | ||
1207 | auditd_pid = auditd_pid_vnr(); | |
1208 | /* only the current auditd can unregister itself */ | |
1209 | if ((!new_pid) && (new_pid != auditd_pid)) { | |
1210 | audit_log_config_change("audit_pid", new_pid, | |
1211 | auditd_pid, 0); | |
1212 | return -EACCES; | |
1213 | } | |
1214 | /* replacing a healthy auditd is not allowed */ | |
1215 | if (auditd_pid && new_pid) { | |
1216 | audit_log_config_change("audit_pid", new_pid, | |
1217 | auditd_pid, 0); | |
1218 | return -EEXIST; | |
1219 | } | |
1220 | ||
1221 | if (new_pid) { | |
1222 | /* register a new auditd connection */ | |
1223 | err = auditd_set(req_pid, | |
1224 | NETLINK_CB(skb).portid, | |
1225 | sock_net(NETLINK_CB(skb).sk)); | |
1226 | if (audit_enabled != AUDIT_OFF) | |
1227 | audit_log_config_change("audit_pid", | |
1228 | new_pid, | |
1229 | auditd_pid, | |
1230 | err ? 0 : 1); | |
1231 | if (err) | |
1232 | return err; | |
1233 | ||
1234 | /* try to process any backlog */ | |
1235 | wake_up_interruptible(&kauditd_wait); | |
1236 | } else { | |
1237 | if (audit_enabled != AUDIT_OFF) | |
1238 | audit_log_config_change("audit_pid", | |
1239 | new_pid, | |
1240 | auditd_pid, 1); | |
1241 | ||
1242 | /* unregister the auditd connection */ | |
1243 | auditd_reset(NULL); | |
1244 | } | |
1245 | } | |
1246 | if (s.mask & AUDIT_STATUS_RATE_LIMIT) { | |
1247 | err = audit_set_rate_limit(s.rate_limit); | |
1248 | if (err < 0) | |
1249 | return err; | |
1250 | } | |
1251 | if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) { | |
1252 | err = audit_set_backlog_limit(s.backlog_limit); | |
1253 | if (err < 0) | |
1254 | return err; | |
1255 | } | |
1256 | if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) { | |
1257 | if (sizeof(s) > (size_t)nlh->nlmsg_len) | |
1258 | return -EINVAL; | |
1259 | if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME) | |
1260 | return -EINVAL; | |
1261 | err = audit_set_backlog_wait_time(s.backlog_wait_time); | |
1262 | if (err < 0) | |
1263 | return err; | |
1264 | } | |
1265 | if (s.mask == AUDIT_STATUS_LOST) { | |
1266 | u32 lost = atomic_xchg(&audit_lost, 0); | |
1267 | ||
1268 | audit_log_config_change("lost", 0, lost, 1); | |
1269 | return lost; | |
1270 | } | |
1271 | break; | |
1272 | } | |
1273 | case AUDIT_GET_FEATURE: | |
1274 | err = audit_get_feature(skb); | |
1275 | if (err) | |
1276 | return err; | |
1277 | break; | |
1278 | case AUDIT_SET_FEATURE: | |
1279 | err = audit_set_feature(skb); | |
1280 | if (err) | |
1281 | return err; | |
1282 | break; | |
1283 | case AUDIT_USER: | |
1284 | case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG: | |
1285 | case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2: | |
1286 | if (!audit_enabled && msg_type != AUDIT_USER_AVC) | |
1287 | return 0; | |
1288 | ||
1289 | err = audit_filter(msg_type, AUDIT_FILTER_USER); | |
1290 | if (err == 1) { /* match or error */ | |
1291 | err = 0; | |
1292 | if (msg_type == AUDIT_USER_TTY) { | |
1293 | err = tty_audit_push(); | |
1294 | if (err) | |
1295 | break; | |
1296 | } | |
1297 | audit_log_common_recv_msg(&ab, msg_type); | |
1298 | if (msg_type != AUDIT_USER_TTY) | |
1299 | audit_log_format(ab, " msg='%.*s'", | |
1300 | AUDIT_MESSAGE_TEXT_MAX, | |
1301 | (char *)data); | |
1302 | else { | |
1303 | int size; | |
1304 | ||
1305 | audit_log_format(ab, " data="); | |
1306 | size = nlmsg_len(nlh); | |
1307 | if (size > 0 && | |
1308 | ((unsigned char *)data)[size - 1] == '\0') | |
1309 | size--; | |
1310 | audit_log_n_untrustedstring(ab, data, size); | |
1311 | } | |
1312 | audit_log_end(ab); | |
1313 | } | |
1314 | break; | |
1315 | case AUDIT_ADD_RULE: | |
1316 | case AUDIT_DEL_RULE: | |
1317 | if (nlmsg_len(nlh) < sizeof(struct audit_rule_data)) | |
1318 | return -EINVAL; | |
1319 | if (audit_enabled == AUDIT_LOCKED) { | |
1320 | audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE); | |
1321 | audit_log_format(ab, " audit_enabled=%d res=0", audit_enabled); | |
1322 | audit_log_end(ab); | |
1323 | return -EPERM; | |
1324 | } | |
1325 | err = audit_rule_change(msg_type, seq, data, nlmsg_len(nlh)); | |
1326 | break; | |
1327 | case AUDIT_LIST_RULES: | |
1328 | err = audit_list_rules_send(skb, seq); | |
1329 | break; | |
1330 | case AUDIT_TRIM: | |
1331 | audit_trim_trees(); | |
1332 | audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE); | |
1333 | audit_log_format(ab, " op=trim res=1"); | |
1334 | audit_log_end(ab); | |
1335 | break; | |
1336 | case AUDIT_MAKE_EQUIV: { | |
1337 | void *bufp = data; | |
1338 | u32 sizes[2]; | |
1339 | size_t msglen = nlmsg_len(nlh); | |
1340 | char *old, *new; | |
1341 | ||
1342 | err = -EINVAL; | |
1343 | if (msglen < 2 * sizeof(u32)) | |
1344 | break; | |
1345 | memcpy(sizes, bufp, 2 * sizeof(u32)); | |
1346 | bufp += 2 * sizeof(u32); | |
1347 | msglen -= 2 * sizeof(u32); | |
1348 | old = audit_unpack_string(&bufp, &msglen, sizes[0]); | |
1349 | if (IS_ERR(old)) { | |
1350 | err = PTR_ERR(old); | |
1351 | break; | |
1352 | } | |
1353 | new = audit_unpack_string(&bufp, &msglen, sizes[1]); | |
1354 | if (IS_ERR(new)) { | |
1355 | err = PTR_ERR(new); | |
1356 | kfree(old); | |
1357 | break; | |
1358 | } | |
1359 | /* OK, here comes... */ | |
1360 | err = audit_tag_tree(old, new); | |
1361 | ||
1362 | audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE); | |
1363 | ||
1364 | audit_log_format(ab, " op=make_equiv old="); | |
1365 | audit_log_untrustedstring(ab, old); | |
1366 | audit_log_format(ab, " new="); | |
1367 | audit_log_untrustedstring(ab, new); | |
1368 | audit_log_format(ab, " res=%d", !err); | |
1369 | audit_log_end(ab); | |
1370 | kfree(old); | |
1371 | kfree(new); | |
1372 | break; | |
1373 | } | |
1374 | case AUDIT_SIGNAL_INFO: | |
1375 | len = 0; | |
1376 | if (audit_sig_sid) { | |
1377 | err = security_secid_to_secctx(audit_sig_sid, &ctx, &len); | |
1378 | if (err) | |
1379 | return err; | |
1380 | } | |
1381 | sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL); | |
1382 | if (!sig_data) { | |
1383 | if (audit_sig_sid) | |
1384 | security_release_secctx(ctx, len); | |
1385 | return -ENOMEM; | |
1386 | } | |
1387 | sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid); | |
1388 | sig_data->pid = audit_sig_pid; | |
1389 | if (audit_sig_sid) { | |
1390 | memcpy(sig_data->ctx, ctx, len); | |
1391 | security_release_secctx(ctx, len); | |
1392 | } | |
1393 | audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0, | |
1394 | sig_data, sizeof(*sig_data) + len); | |
1395 | kfree(sig_data); | |
1396 | break; | |
1397 | case AUDIT_TTY_GET: { | |
1398 | struct audit_tty_status s; | |
1399 | unsigned int t; | |
1400 | ||
1401 | t = READ_ONCE(current->signal->audit_tty); | |
1402 | s.enabled = t & AUDIT_TTY_ENABLE; | |
1403 | s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD); | |
1404 | ||
1405 | audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s)); | |
1406 | break; | |
1407 | } | |
1408 | case AUDIT_TTY_SET: { | |
1409 | struct audit_tty_status s, old; | |
1410 | struct audit_buffer *ab; | |
1411 | unsigned int t; | |
1412 | ||
1413 | memset(&s, 0, sizeof(s)); | |
1414 | /* guard against past and future API changes */ | |
1415 | memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh))); | |
1416 | /* check if new data is valid */ | |
1417 | if ((s.enabled != 0 && s.enabled != 1) || | |
1418 | (s.log_passwd != 0 && s.log_passwd != 1)) | |
1419 | err = -EINVAL; | |
1420 | ||
1421 | if (err) | |
1422 | t = READ_ONCE(current->signal->audit_tty); | |
1423 | else { | |
1424 | t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD); | |
1425 | t = xchg(¤t->signal->audit_tty, t); | |
1426 | } | |
1427 | old.enabled = t & AUDIT_TTY_ENABLE; | |
1428 | old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD); | |
1429 | ||
1430 | audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE); | |
1431 | audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d" | |
1432 | " old-log_passwd=%d new-log_passwd=%d res=%d", | |
1433 | old.enabled, s.enabled, old.log_passwd, | |
1434 | s.log_passwd, !err); | |
1435 | audit_log_end(ab); | |
1436 | break; | |
1437 | } | |
1438 | default: | |
1439 | err = -EINVAL; | |
1440 | break; | |
1441 | } | |
1442 | ||
1443 | return err < 0 ? err : 0; | |
1444 | } | |
1445 | ||
1446 | /** | |
1447 | * audit_receive - receive messages from a netlink control socket | |
1448 | * @skb: the message buffer | |
1449 | * | |
1450 | * Parse the provided skb and deal with any messages that may be present, | |
1451 | * malformed skbs are discarded. | |
1452 | */ | |
1453 | static void audit_receive(struct sk_buff *skb) | |
1454 | { | |
1455 | struct nlmsghdr *nlh; | |
1456 | /* | |
1457 | * len MUST be signed for nlmsg_next to be able to dec it below 0 | |
1458 | * if the nlmsg_len was not aligned | |
1459 | */ | |
1460 | int len; | |
1461 | int err; | |
1462 | ||
1463 | nlh = nlmsg_hdr(skb); | |
1464 | len = skb->len; | |
1465 | ||
1466 | mutex_lock(&audit_cmd_mutex); | |
1467 | while (nlmsg_ok(nlh, len)) { | |
1468 | err = audit_receive_msg(skb, nlh); | |
1469 | /* if err or if this message says it wants a response */ | |
1470 | if (err || (nlh->nlmsg_flags & NLM_F_ACK)) | |
1471 | netlink_ack(skb, nlh, err, NULL); | |
1472 | ||
1473 | nlh = nlmsg_next(nlh, &len); | |
1474 | } | |
1475 | mutex_unlock(&audit_cmd_mutex); | |
1476 | } | |
1477 | ||
1478 | /* Run custom bind function on netlink socket group connect or bind requests. */ | |
1479 | static int audit_bind(struct net *net, int group) | |
1480 | { | |
1481 | if (!capable(CAP_AUDIT_READ)) | |
1482 | return -EPERM; | |
1483 | ||
1484 | return 0; | |
1485 | } | |
1486 | ||
1487 | static int __net_init audit_net_init(struct net *net) | |
1488 | { | |
1489 | struct netlink_kernel_cfg cfg = { | |
1490 | .input = audit_receive, | |
1491 | .bind = audit_bind, | |
1492 | .flags = NL_CFG_F_NONROOT_RECV, | |
1493 | .groups = AUDIT_NLGRP_MAX, | |
1494 | }; | |
1495 | ||
1496 | struct audit_net *aunet = net_generic(net, audit_net_id); | |
1497 | ||
1498 | aunet->sk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg); | |
1499 | if (aunet->sk == NULL) { | |
1500 | audit_panic("cannot initialize netlink socket in namespace"); | |
1501 | return -ENOMEM; | |
1502 | } | |
1503 | aunet->sk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT; | |
1504 | ||
1505 | return 0; | |
1506 | } | |
1507 | ||
1508 | static void __net_exit audit_net_exit(struct net *net) | |
1509 | { | |
1510 | struct audit_net *aunet = net_generic(net, audit_net_id); | |
1511 | ||
1512 | /* NOTE: you would think that we would want to check the auditd | |
1513 | * connection and potentially reset it here if it lives in this | |
1514 | * namespace, but since the auditd connection tracking struct holds a | |
1515 | * reference to this namespace (see auditd_set()) we are only ever | |
1516 | * going to get here after that connection has been released */ | |
1517 | ||
1518 | netlink_kernel_release(aunet->sk); | |
1519 | } | |
1520 | ||
1521 | static struct pernet_operations audit_net_ops __net_initdata = { | |
1522 | .init = audit_net_init, | |
1523 | .exit = audit_net_exit, | |
1524 | .id = &audit_net_id, | |
1525 | .size = sizeof(struct audit_net), | |
1526 | }; | |
1527 | ||
1528 | /* Initialize audit support at boot time. */ | |
1529 | static int __init audit_init(void) | |
1530 | { | |
1531 | int i; | |
1532 | ||
1533 | if (audit_initialized == AUDIT_DISABLED) | |
1534 | return 0; | |
1535 | ||
1536 | audit_buffer_cache = kmem_cache_create("audit_buffer", | |
1537 | sizeof(struct audit_buffer), | |
1538 | 0, SLAB_PANIC, NULL); | |
1539 | ||
1540 | skb_queue_head_init(&audit_queue); | |
1541 | skb_queue_head_init(&audit_retry_queue); | |
1542 | skb_queue_head_init(&audit_hold_queue); | |
1543 | ||
1544 | for (i = 0; i < AUDIT_INODE_BUCKETS; i++) | |
1545 | INIT_LIST_HEAD(&audit_inode_hash[i]); | |
1546 | ||
1547 | pr_info("initializing netlink subsys (%s)\n", | |
1548 | audit_default ? "enabled" : "disabled"); | |
1549 | register_pernet_subsys(&audit_net_ops); | |
1550 | ||
1551 | audit_initialized = AUDIT_INITIALIZED; | |
1552 | audit_enabled = audit_default; | |
1553 | audit_ever_enabled |= !!audit_default; | |
1554 | ||
1555 | kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd"); | |
1556 | if (IS_ERR(kauditd_task)) { | |
1557 | int err = PTR_ERR(kauditd_task); | |
1558 | panic("audit: failed to start the kauditd thread (%d)\n", err); | |
1559 | } | |
1560 | ||
1561 | audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, | |
1562 | "state=initialized audit_enabled=%u res=1", | |
1563 | audit_enabled); | |
1564 | ||
1565 | return 0; | |
1566 | } | |
1567 | __initcall(audit_init); | |
1568 | ||
1569 | /* Process kernel command-line parameter at boot time. audit=0 or audit=1. */ | |
1570 | static int __init audit_enable(char *str) | |
1571 | { | |
1572 | audit_default = !!simple_strtol(str, NULL, 0); | |
1573 | if (!audit_default) | |
1574 | audit_initialized = AUDIT_DISABLED; | |
1575 | ||
1576 | pr_info("%s\n", audit_default ? | |
1577 | "enabled (after initialization)" : "disabled (until reboot)"); | |
1578 | ||
1579 | return 1; | |
1580 | } | |
1581 | __setup("audit=", audit_enable); | |
1582 | ||
1583 | /* Process kernel command-line parameter at boot time. | |
1584 | * audit_backlog_limit=<n> */ | |
1585 | static int __init audit_backlog_limit_set(char *str) | |
1586 | { | |
1587 | u32 audit_backlog_limit_arg; | |
1588 | ||
1589 | pr_info("audit_backlog_limit: "); | |
1590 | if (kstrtouint(str, 0, &audit_backlog_limit_arg)) { | |
1591 | pr_cont("using default of %u, unable to parse %s\n", | |
1592 | audit_backlog_limit, str); | |
1593 | return 1; | |
1594 | } | |
1595 | ||
1596 | audit_backlog_limit = audit_backlog_limit_arg; | |
1597 | pr_cont("%d\n", audit_backlog_limit); | |
1598 | ||
1599 | return 1; | |
1600 | } | |
1601 | __setup("audit_backlog_limit=", audit_backlog_limit_set); | |
1602 | ||
1603 | static void audit_buffer_free(struct audit_buffer *ab) | |
1604 | { | |
1605 | if (!ab) | |
1606 | return; | |
1607 | ||
1608 | kfree_skb(ab->skb); | |
1609 | kmem_cache_free(audit_buffer_cache, ab); | |
1610 | } | |
1611 | ||
1612 | static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx, | |
1613 | gfp_t gfp_mask, int type) | |
1614 | { | |
1615 | struct audit_buffer *ab; | |
1616 | ||
1617 | ab = kmem_cache_alloc(audit_buffer_cache, gfp_mask); | |
1618 | if (!ab) | |
1619 | return NULL; | |
1620 | ||
1621 | ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask); | |
1622 | if (!ab->skb) | |
1623 | goto err; | |
1624 | if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0)) | |
1625 | goto err; | |
1626 | ||
1627 | ab->ctx = ctx; | |
1628 | ab->gfp_mask = gfp_mask; | |
1629 | ||
1630 | return ab; | |
1631 | ||
1632 | err: | |
1633 | audit_buffer_free(ab); | |
1634 | return NULL; | |
1635 | } | |
1636 | ||
1637 | /** | |
1638 | * audit_serial - compute a serial number for the audit record | |
1639 | * | |
1640 | * Compute a serial number for the audit record. Audit records are | |
1641 | * written to user-space as soon as they are generated, so a complete | |
1642 | * audit record may be written in several pieces. The timestamp of the | |
1643 | * record and this serial number are used by the user-space tools to | |
1644 | * determine which pieces belong to the same audit record. The | |
1645 | * (timestamp,serial) tuple is unique for each syscall and is live from | |
1646 | * syscall entry to syscall exit. | |
1647 | * | |
1648 | * NOTE: Another possibility is to store the formatted records off the | |
1649 | * audit context (for those records that have a context), and emit them | |
1650 | * all at syscall exit. However, this could delay the reporting of | |
1651 | * significant errors until syscall exit (or never, if the system | |
1652 | * halts). | |
1653 | */ | |
1654 | unsigned int audit_serial(void) | |
1655 | { | |
1656 | static atomic_t serial = ATOMIC_INIT(0); | |
1657 | ||
1658 | return atomic_add_return(1, &serial); | |
1659 | } | |
1660 | ||
1661 | static inline void audit_get_stamp(struct audit_context *ctx, | |
1662 | struct timespec64 *t, unsigned int *serial) | |
1663 | { | |
1664 | if (!ctx || !auditsc_get_stamp(ctx, t, serial)) { | |
1665 | ktime_get_real_ts64(t); | |
1666 | *serial = audit_serial(); | |
1667 | } | |
1668 | } | |
1669 | ||
1670 | /** | |
1671 | * audit_log_start - obtain an audit buffer | |
1672 | * @ctx: audit_context (may be NULL) | |
1673 | * @gfp_mask: type of allocation | |
1674 | * @type: audit message type | |
1675 | * | |
1676 | * Returns audit_buffer pointer on success or NULL on error. | |
1677 | * | |
1678 | * Obtain an audit buffer. This routine does locking to obtain the | |
1679 | * audit buffer, but then no locking is required for calls to | |
1680 | * audit_log_*format. If the task (ctx) is a task that is currently in a | |
1681 | * syscall, then the syscall is marked as auditable and an audit record | |
1682 | * will be written at syscall exit. If there is no associated task, then | |
1683 | * task context (ctx) should be NULL. | |
1684 | */ | |
1685 | struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, | |
1686 | int type) | |
1687 | { | |
1688 | struct audit_buffer *ab; | |
1689 | struct timespec64 t; | |
1690 | unsigned int uninitialized_var(serial); | |
1691 | ||
1692 | if (audit_initialized != AUDIT_INITIALIZED) | |
1693 | return NULL; | |
1694 | ||
1695 | if (unlikely(!audit_filter(type, AUDIT_FILTER_TYPE))) | |
1696 | return NULL; | |
1697 | ||
1698 | /* NOTE: don't ever fail/sleep on these two conditions: | |
1699 | * 1. auditd generated record - since we need auditd to drain the | |
1700 | * queue; also, when we are checking for auditd, compare PIDs using | |
1701 | * task_tgid_vnr() since auditd_pid is set in audit_receive_msg() | |
1702 | * using a PID anchored in the caller's namespace | |
1703 | * 2. generator holding the audit_cmd_mutex - we don't want to block | |
1704 | * while holding the mutex */ | |
1705 | if (!(auditd_test_task(current) || | |
1706 | (current == __mutex_owner(&audit_cmd_mutex)))) { | |
1707 | long stime = audit_backlog_wait_time; | |
1708 | ||
1709 | while (audit_backlog_limit && | |
1710 | (skb_queue_len(&audit_queue) > audit_backlog_limit)) { | |
1711 | /* wake kauditd to try and flush the queue */ | |
1712 | wake_up_interruptible(&kauditd_wait); | |
1713 | ||
1714 | /* sleep if we are allowed and we haven't exhausted our | |
1715 | * backlog wait limit */ | |
1716 | if (gfpflags_allow_blocking(gfp_mask) && (stime > 0)) { | |
1717 | DECLARE_WAITQUEUE(wait, current); | |
1718 | ||
1719 | add_wait_queue_exclusive(&audit_backlog_wait, | |
1720 | &wait); | |
1721 | set_current_state(TASK_UNINTERRUPTIBLE); | |
1722 | stime = schedule_timeout(stime); | |
1723 | remove_wait_queue(&audit_backlog_wait, &wait); | |
1724 | } else { | |
1725 | if (audit_rate_check() && printk_ratelimit()) | |
1726 | pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n", | |
1727 | skb_queue_len(&audit_queue), | |
1728 | audit_backlog_limit); | |
1729 | audit_log_lost("backlog limit exceeded"); | |
1730 | return NULL; | |
1731 | } | |
1732 | } | |
1733 | } | |
1734 | ||
1735 | ab = audit_buffer_alloc(ctx, gfp_mask, type); | |
1736 | if (!ab) { | |
1737 | audit_log_lost("out of memory in audit_log_start"); | |
1738 | return NULL; | |
1739 | } | |
1740 | ||
1741 | audit_get_stamp(ab->ctx, &t, &serial); | |
1742 | audit_log_format(ab, "audit(%llu.%03lu:%u): ", | |
1743 | (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial); | |
1744 | ||
1745 | return ab; | |
1746 | } | |
1747 | ||
1748 | /** | |
1749 | * audit_expand - expand skb in the audit buffer | |
1750 | * @ab: audit_buffer | |
1751 | * @extra: space to add at tail of the skb | |
1752 | * | |
1753 | * Returns 0 (no space) on failed expansion, or available space if | |
1754 | * successful. | |
1755 | */ | |
1756 | static inline int audit_expand(struct audit_buffer *ab, int extra) | |
1757 | { | |
1758 | struct sk_buff *skb = ab->skb; | |
1759 | int oldtail = skb_tailroom(skb); | |
1760 | int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask); | |
1761 | int newtail = skb_tailroom(skb); | |
1762 | ||
1763 | if (ret < 0) { | |
1764 | audit_log_lost("out of memory in audit_expand"); | |
1765 | return 0; | |
1766 | } | |
1767 | ||
1768 | skb->truesize += newtail - oldtail; | |
1769 | return newtail; | |
1770 | } | |
1771 | ||
1772 | /* | |
1773 | * Format an audit message into the audit buffer. If there isn't enough | |
1774 | * room in the audit buffer, more room will be allocated and vsnprint | |
1775 | * will be called a second time. Currently, we assume that a printk | |
1776 | * can't format message larger than 1024 bytes, so we don't either. | |
1777 | */ | |
1778 | static void audit_log_vformat(struct audit_buffer *ab, const char *fmt, | |
1779 | va_list args) | |
1780 | { | |
1781 | int len, avail; | |
1782 | struct sk_buff *skb; | |
1783 | va_list args2; | |
1784 | ||
1785 | if (!ab) | |
1786 | return; | |
1787 | ||
1788 | BUG_ON(!ab->skb); | |
1789 | skb = ab->skb; | |
1790 | avail = skb_tailroom(skb); | |
1791 | if (avail == 0) { | |
1792 | avail = audit_expand(ab, AUDIT_BUFSIZ); | |
1793 | if (!avail) | |
1794 | goto out; | |
1795 | } | |
1796 | va_copy(args2, args); | |
1797 | len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args); | |
1798 | if (len >= avail) { | |
1799 | /* The printk buffer is 1024 bytes long, so if we get | |
1800 | * here and AUDIT_BUFSIZ is at least 1024, then we can | |
1801 | * log everything that printk could have logged. */ | |
1802 | avail = audit_expand(ab, | |
1803 | max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail)); | |
1804 | if (!avail) | |
1805 | goto out_va_end; | |
1806 | len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2); | |
1807 | } | |
1808 | if (len > 0) | |
1809 | skb_put(skb, len); | |
1810 | out_va_end: | |
1811 | va_end(args2); | |
1812 | out: | |
1813 | return; | |
1814 | } | |
1815 | ||
1816 | /** | |
1817 | * audit_log_format - format a message into the audit buffer. | |
1818 | * @ab: audit_buffer | |
1819 | * @fmt: format string | |
1820 | * @...: optional parameters matching @fmt string | |
1821 | * | |
1822 | * All the work is done in audit_log_vformat. | |
1823 | */ | |
1824 | void audit_log_format(struct audit_buffer *ab, const char *fmt, ...) | |
1825 | { | |
1826 | va_list args; | |
1827 | ||
1828 | if (!ab) | |
1829 | return; | |
1830 | va_start(args, fmt); | |
1831 | audit_log_vformat(ab, fmt, args); | |
1832 | va_end(args); | |
1833 | } | |
1834 | ||
1835 | /** | |
1836 | * audit_log_hex - convert a buffer to hex and append it to the audit skb | |
1837 | * @ab: the audit_buffer | |
1838 | * @buf: buffer to convert to hex | |
1839 | * @len: length of @buf to be converted | |
1840 | * | |
1841 | * No return value; failure to expand is silently ignored. | |
1842 | * | |
1843 | * This function will take the passed buf and convert it into a string of | |
1844 | * ascii hex digits. The new string is placed onto the skb. | |
1845 | */ | |
1846 | void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf, | |
1847 | size_t len) | |
1848 | { | |
1849 | int i, avail, new_len; | |
1850 | unsigned char *ptr; | |
1851 | struct sk_buff *skb; | |
1852 | ||
1853 | if (!ab) | |
1854 | return; | |
1855 | ||
1856 | BUG_ON(!ab->skb); | |
1857 | skb = ab->skb; | |
1858 | avail = skb_tailroom(skb); | |
1859 | new_len = len<<1; | |
1860 | if (new_len >= avail) { | |
1861 | /* Round the buffer request up to the next multiple */ | |
1862 | new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1); | |
1863 | avail = audit_expand(ab, new_len); | |
1864 | if (!avail) | |
1865 | return; | |
1866 | } | |
1867 | ||
1868 | ptr = skb_tail_pointer(skb); | |
1869 | for (i = 0; i < len; i++) | |
1870 | ptr = hex_byte_pack_upper(ptr, buf[i]); | |
1871 | *ptr = 0; | |
1872 | skb_put(skb, len << 1); /* new string is twice the old string */ | |
1873 | } | |
1874 | ||
1875 | /* | |
1876 | * Format a string of no more than slen characters into the audit buffer, | |
1877 | * enclosed in quote marks. | |
1878 | */ | |
1879 | void audit_log_n_string(struct audit_buffer *ab, const char *string, | |
1880 | size_t slen) | |
1881 | { | |
1882 | int avail, new_len; | |
1883 | unsigned char *ptr; | |
1884 | struct sk_buff *skb; | |
1885 | ||
1886 | if (!ab) | |
1887 | return; | |
1888 | ||
1889 | BUG_ON(!ab->skb); | |
1890 | skb = ab->skb; | |
1891 | avail = skb_tailroom(skb); | |
1892 | new_len = slen + 3; /* enclosing quotes + null terminator */ | |
1893 | if (new_len > avail) { | |
1894 | avail = audit_expand(ab, new_len); | |
1895 | if (!avail) | |
1896 | return; | |
1897 | } | |
1898 | ptr = skb_tail_pointer(skb); | |
1899 | *ptr++ = '"'; | |
1900 | memcpy(ptr, string, slen); | |
1901 | ptr += slen; | |
1902 | *ptr++ = '"'; | |
1903 | *ptr = 0; | |
1904 | skb_put(skb, slen + 2); /* don't include null terminator */ | |
1905 | } | |
1906 | ||
1907 | /** | |
1908 | * audit_string_contains_control - does a string need to be logged in hex | |
1909 | * @string: string to be checked | |
1910 | * @len: max length of the string to check | |
1911 | */ | |
1912 | bool audit_string_contains_control(const char *string, size_t len) | |
1913 | { | |
1914 | const unsigned char *p; | |
1915 | for (p = string; p < (const unsigned char *)string + len; p++) { | |
1916 | if (*p == '"' || *p < 0x21 || *p > 0x7e) | |
1917 | return true; | |
1918 | } | |
1919 | return false; | |
1920 | } | |
1921 | ||
1922 | /** | |
1923 | * audit_log_n_untrustedstring - log a string that may contain random characters | |
1924 | * @ab: audit_buffer | |
1925 | * @len: length of string (not including trailing null) | |
1926 | * @string: string to be logged | |
1927 | * | |
1928 | * This code will escape a string that is passed to it if the string | |
1929 | * contains a control character, unprintable character, double quote mark, | |
1930 | * or a space. Unescaped strings will start and end with a double quote mark. | |
1931 | * Strings that are escaped are printed in hex (2 digits per char). | |
1932 | * | |
1933 | * The caller specifies the number of characters in the string to log, which may | |
1934 | * or may not be the entire string. | |
1935 | */ | |
1936 | void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string, | |
1937 | size_t len) | |
1938 | { | |
1939 | if (audit_string_contains_control(string, len)) | |
1940 | audit_log_n_hex(ab, string, len); | |
1941 | else | |
1942 | audit_log_n_string(ab, string, len); | |
1943 | } | |
1944 | ||
1945 | /** | |
1946 | * audit_log_untrustedstring - log a string that may contain random characters | |
1947 | * @ab: audit_buffer | |
1948 | * @string: string to be logged | |
1949 | * | |
1950 | * Same as audit_log_n_untrustedstring(), except that strlen is used to | |
1951 | * determine string length. | |
1952 | */ | |
1953 | void audit_log_untrustedstring(struct audit_buffer *ab, const char *string) | |
1954 | { | |
1955 | audit_log_n_untrustedstring(ab, string, strlen(string)); | |
1956 | } | |
1957 | ||
1958 | /* This is a helper-function to print the escaped d_path */ | |
1959 | void audit_log_d_path(struct audit_buffer *ab, const char *prefix, | |
1960 | const struct path *path) | |
1961 | { | |
1962 | char *p, *pathname; | |
1963 | ||
1964 | if (prefix) | |
1965 | audit_log_format(ab, "%s", prefix); | |
1966 | ||
1967 | /* We will allow 11 spaces for ' (deleted)' to be appended */ | |
1968 | pathname = kmalloc(PATH_MAX+11, ab->gfp_mask); | |
1969 | if (!pathname) { | |
1970 | audit_log_string(ab, "<no_memory>"); | |
1971 | return; | |
1972 | } | |
1973 | p = d_path(path, pathname, PATH_MAX+11); | |
1974 | if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */ | |
1975 | /* FIXME: can we save some information here? */ | |
1976 | audit_log_string(ab, "<too_long>"); | |
1977 | } else | |
1978 | audit_log_untrustedstring(ab, p); | |
1979 | kfree(pathname); | |
1980 | } | |
1981 | ||
1982 | void audit_log_session_info(struct audit_buffer *ab) | |
1983 | { | |
1984 | unsigned int sessionid = audit_get_sessionid(current); | |
1985 | uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current)); | |
1986 | ||
1987 | audit_log_format(ab, " auid=%u ses=%u", auid, sessionid); | |
1988 | } | |
1989 | ||
1990 | void audit_log_key(struct audit_buffer *ab, char *key) | |
1991 | { | |
1992 | audit_log_format(ab, " key="); | |
1993 | if (key) | |
1994 | audit_log_untrustedstring(ab, key); | |
1995 | else | |
1996 | audit_log_format(ab, "(null)"); | |
1997 | } | |
1998 | ||
1999 | void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap) | |
2000 | { | |
2001 | int i; | |
2002 | ||
2003 | audit_log_format(ab, " %s=", prefix); | |
2004 | CAP_FOR_EACH_U32(i) { | |
2005 | audit_log_format(ab, "%08x", | |
2006 | cap->cap[CAP_LAST_U32 - i]); | |
2007 | } | |
2008 | } | |
2009 | ||
2010 | static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name) | |
2011 | { | |
2012 | audit_log_cap(ab, "cap_fp", &name->fcap.permitted); | |
2013 | audit_log_cap(ab, "cap_fi", &name->fcap.inheritable); | |
2014 | audit_log_format(ab, " cap_fe=%d cap_fver=%x", | |
2015 | name->fcap.fE, name->fcap_ver); | |
2016 | } | |
2017 | ||
2018 | static inline int audit_copy_fcaps(struct audit_names *name, | |
2019 | const struct dentry *dentry) | |
2020 | { | |
2021 | struct cpu_vfs_cap_data caps; | |
2022 | int rc; | |
2023 | ||
2024 | if (!dentry) | |
2025 | return 0; | |
2026 | ||
2027 | rc = get_vfs_caps_from_disk(dentry, &caps); | |
2028 | if (rc) | |
2029 | return rc; | |
2030 | ||
2031 | name->fcap.permitted = caps.permitted; | |
2032 | name->fcap.inheritable = caps.inheritable; | |
2033 | name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE); | |
2034 | name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >> | |
2035 | VFS_CAP_REVISION_SHIFT; | |
2036 | ||
2037 | return 0; | |
2038 | } | |
2039 | ||
2040 | /* Copy inode data into an audit_names. */ | |
2041 | void audit_copy_inode(struct audit_names *name, const struct dentry *dentry, | |
2042 | struct inode *inode) | |
2043 | { | |
2044 | name->ino = inode->i_ino; | |
2045 | name->dev = inode->i_sb->s_dev; | |
2046 | name->mode = inode->i_mode; | |
2047 | name->uid = inode->i_uid; | |
2048 | name->gid = inode->i_gid; | |
2049 | name->rdev = inode->i_rdev; | |
2050 | security_inode_getsecid(inode, &name->osid); | |
2051 | audit_copy_fcaps(name, dentry); | |
2052 | } | |
2053 | ||
2054 | /** | |
2055 | * audit_log_name - produce AUDIT_PATH record from struct audit_names | |
2056 | * @context: audit_context for the task | |
2057 | * @n: audit_names structure with reportable details | |
2058 | * @path: optional path to report instead of audit_names->name | |
2059 | * @record_num: record number to report when handling a list of names | |
2060 | * @call_panic: optional pointer to int that will be updated if secid fails | |
2061 | */ | |
2062 | void audit_log_name(struct audit_context *context, struct audit_names *n, | |
2063 | const struct path *path, int record_num, int *call_panic) | |
2064 | { | |
2065 | struct audit_buffer *ab; | |
2066 | ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH); | |
2067 | if (!ab) | |
2068 | return; | |
2069 | ||
2070 | audit_log_format(ab, "item=%d", record_num); | |
2071 | ||
2072 | if (path) | |
2073 | audit_log_d_path(ab, " name=", path); | |
2074 | else if (n->name) { | |
2075 | switch (n->name_len) { | |
2076 | case AUDIT_NAME_FULL: | |
2077 | /* log the full path */ | |
2078 | audit_log_format(ab, " name="); | |
2079 | audit_log_untrustedstring(ab, n->name->name); | |
2080 | break; | |
2081 | case 0: | |
2082 | /* name was specified as a relative path and the | |
2083 | * directory component is the cwd */ | |
2084 | audit_log_d_path(ab, " name=", &context->pwd); | |
2085 | break; | |
2086 | default: | |
2087 | /* log the name's directory component */ | |
2088 | audit_log_format(ab, " name="); | |
2089 | audit_log_n_untrustedstring(ab, n->name->name, | |
2090 | n->name_len); | |
2091 | } | |
2092 | } else | |
2093 | audit_log_format(ab, " name=(null)"); | |
2094 | ||
2095 | if (n->ino != AUDIT_INO_UNSET) | |
2096 | audit_log_format(ab, " inode=%lu" | |
2097 | " dev=%02x:%02x mode=%#ho" | |
2098 | " ouid=%u ogid=%u rdev=%02x:%02x", | |
2099 | n->ino, | |
2100 | MAJOR(n->dev), | |
2101 | MINOR(n->dev), | |
2102 | n->mode, | |
2103 | from_kuid(&init_user_ns, n->uid), | |
2104 | from_kgid(&init_user_ns, n->gid), | |
2105 | MAJOR(n->rdev), | |
2106 | MINOR(n->rdev)); | |
2107 | if (n->osid != 0) { | |
2108 | char *ctx = NULL; | |
2109 | u32 len; | |
2110 | if (security_secid_to_secctx( | |
2111 | n->osid, &ctx, &len)) { | |
2112 | audit_log_format(ab, " osid=%u", n->osid); | |
2113 | if (call_panic) | |
2114 | *call_panic = 2; | |
2115 | } else { | |
2116 | audit_log_format(ab, " obj=%s", ctx); | |
2117 | security_release_secctx(ctx, len); | |
2118 | } | |
2119 | } | |
2120 | ||
2121 | /* log the audit_names record type */ | |
2122 | audit_log_format(ab, " nametype="); | |
2123 | switch(n->type) { | |
2124 | case AUDIT_TYPE_NORMAL: | |
2125 | audit_log_format(ab, "NORMAL"); | |
2126 | break; | |
2127 | case AUDIT_TYPE_PARENT: | |
2128 | audit_log_format(ab, "PARENT"); | |
2129 | break; | |
2130 | case AUDIT_TYPE_CHILD_DELETE: | |
2131 | audit_log_format(ab, "DELETE"); | |
2132 | break; | |
2133 | case AUDIT_TYPE_CHILD_CREATE: | |
2134 | audit_log_format(ab, "CREATE"); | |
2135 | break; | |
2136 | default: | |
2137 | audit_log_format(ab, "UNKNOWN"); | |
2138 | break; | |
2139 | } | |
2140 | ||
2141 | audit_log_fcaps(ab, n); | |
2142 | audit_log_end(ab); | |
2143 | } | |
2144 | ||
2145 | int audit_log_task_context(struct audit_buffer *ab) | |
2146 | { | |
2147 | char *ctx = NULL; | |
2148 | unsigned len; | |
2149 | int error; | |
2150 | u32 sid; | |
2151 | ||
2152 | security_task_getsecid(current, &sid); | |
2153 | if (!sid) | |
2154 | return 0; | |
2155 | ||
2156 | error = security_secid_to_secctx(sid, &ctx, &len); | |
2157 | if (error) { | |
2158 | if (error != -EINVAL) | |
2159 | goto error_path; | |
2160 | return 0; | |
2161 | } | |
2162 | ||
2163 | audit_log_format(ab, " subj=%s", ctx); | |
2164 | security_release_secctx(ctx, len); | |
2165 | return 0; | |
2166 | ||
2167 | error_path: | |
2168 | audit_panic("error in audit_log_task_context"); | |
2169 | return error; | |
2170 | } | |
2171 | EXPORT_SYMBOL(audit_log_task_context); | |
2172 | ||
2173 | void audit_log_d_path_exe(struct audit_buffer *ab, | |
2174 | struct mm_struct *mm) | |
2175 | { | |
2176 | struct file *exe_file; | |
2177 | ||
2178 | if (!mm) | |
2179 | goto out_null; | |
2180 | ||
2181 | exe_file = get_mm_exe_file(mm); | |
2182 | if (!exe_file) | |
2183 | goto out_null; | |
2184 | ||
2185 | audit_log_d_path(ab, " exe=", &exe_file->f_path); | |
2186 | fput(exe_file); | |
2187 | return; | |
2188 | out_null: | |
2189 | audit_log_format(ab, " exe=(null)"); | |
2190 | } | |
2191 | ||
2192 | struct tty_struct *audit_get_tty(struct task_struct *tsk) | |
2193 | { | |
2194 | struct tty_struct *tty = NULL; | |
2195 | unsigned long flags; | |
2196 | ||
2197 | spin_lock_irqsave(&tsk->sighand->siglock, flags); | |
2198 | if (tsk->signal) | |
2199 | tty = tty_kref_get(tsk->signal->tty); | |
2200 | spin_unlock_irqrestore(&tsk->sighand->siglock, flags); | |
2201 | return tty; | |
2202 | } | |
2203 | ||
2204 | void audit_put_tty(struct tty_struct *tty) | |
2205 | { | |
2206 | tty_kref_put(tty); | |
2207 | } | |
2208 | ||
2209 | void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk) | |
2210 | { | |
2211 | const struct cred *cred; | |
2212 | char comm[sizeof(tsk->comm)]; | |
2213 | struct tty_struct *tty; | |
2214 | ||
2215 | if (!ab) | |
2216 | return; | |
2217 | ||
2218 | /* tsk == current */ | |
2219 | cred = current_cred(); | |
2220 | tty = audit_get_tty(tsk); | |
2221 | audit_log_format(ab, | |
2222 | " ppid=%d pid=%d auid=%u uid=%u gid=%u" | |
2223 | " euid=%u suid=%u fsuid=%u" | |
2224 | " egid=%u sgid=%u fsgid=%u tty=%s ses=%u", | |
2225 | task_ppid_nr(tsk), | |
2226 | task_tgid_nr(tsk), | |
2227 | from_kuid(&init_user_ns, audit_get_loginuid(tsk)), | |
2228 | from_kuid(&init_user_ns, cred->uid), | |
2229 | from_kgid(&init_user_ns, cred->gid), | |
2230 | from_kuid(&init_user_ns, cred->euid), | |
2231 | from_kuid(&init_user_ns, cred->suid), | |
2232 | from_kuid(&init_user_ns, cred->fsuid), | |
2233 | from_kgid(&init_user_ns, cred->egid), | |
2234 | from_kgid(&init_user_ns, cred->sgid), | |
2235 | from_kgid(&init_user_ns, cred->fsgid), | |
2236 | tty ? tty_name(tty) : "(none)", | |
2237 | audit_get_sessionid(tsk)); | |
2238 | audit_put_tty(tty); | |
2239 | audit_log_format(ab, " comm="); | |
2240 | audit_log_untrustedstring(ab, get_task_comm(comm, tsk)); | |
2241 | audit_log_d_path_exe(ab, tsk->mm); | |
2242 | audit_log_task_context(ab); | |
2243 | } | |
2244 | EXPORT_SYMBOL(audit_log_task_info); | |
2245 | ||
2246 | /** | |
2247 | * audit_log_link_denied - report a link restriction denial | |
2248 | * @operation: specific link operation | |
2249 | * @link: the path that triggered the restriction | |
2250 | */ | |
2251 | void audit_log_link_denied(const char *operation, const struct path *link) | |
2252 | { | |
2253 | struct audit_buffer *ab; | |
2254 | struct audit_names *name; | |
2255 | ||
2256 | name = kzalloc(sizeof(*name), GFP_NOFS); | |
2257 | if (!name) | |
2258 | return; | |
2259 | ||
2260 | /* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */ | |
2261 | ab = audit_log_start(current->audit_context, GFP_KERNEL, | |
2262 | AUDIT_ANOM_LINK); | |
2263 | if (!ab) | |
2264 | goto out; | |
2265 | audit_log_format(ab, "op=%s", operation); | |
2266 | audit_log_task_info(ab, current); | |
2267 | audit_log_format(ab, " res=0"); | |
2268 | audit_log_end(ab); | |
2269 | ||
2270 | /* Generate AUDIT_PATH record with object. */ | |
2271 | name->type = AUDIT_TYPE_NORMAL; | |
2272 | audit_copy_inode(name, link->dentry, d_backing_inode(link->dentry)); | |
2273 | audit_log_name(current->audit_context, name, link, 0, NULL); | |
2274 | out: | |
2275 | kfree(name); | |
2276 | } | |
2277 | ||
2278 | /** | |
2279 | * audit_log_end - end one audit record | |
2280 | * @ab: the audit_buffer | |
2281 | * | |
2282 | * We can not do a netlink send inside an irq context because it blocks (last | |
2283 | * arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a | |
2284 | * queue and a tasklet is scheduled to remove them from the queue outside the | |
2285 | * irq context. May be called in any context. | |
2286 | */ | |
2287 | void audit_log_end(struct audit_buffer *ab) | |
2288 | { | |
2289 | struct sk_buff *skb; | |
2290 | struct nlmsghdr *nlh; | |
2291 | ||
2292 | if (!ab) | |
2293 | return; | |
2294 | ||
2295 | if (audit_rate_check()) { | |
2296 | skb = ab->skb; | |
2297 | ab->skb = NULL; | |
2298 | ||
2299 | /* setup the netlink header, see the comments in | |
2300 | * kauditd_send_multicast_skb() for length quirks */ | |
2301 | nlh = nlmsg_hdr(skb); | |
2302 | nlh->nlmsg_len = skb->len - NLMSG_HDRLEN; | |
2303 | ||
2304 | /* queue the netlink packet and poke the kauditd thread */ | |
2305 | skb_queue_tail(&audit_queue, skb); | |
2306 | wake_up_interruptible(&kauditd_wait); | |
2307 | } else | |
2308 | audit_log_lost("rate limit exceeded"); | |
2309 | ||
2310 | audit_buffer_free(ab); | |
2311 | } | |
2312 | ||
2313 | /** | |
2314 | * audit_log - Log an audit record | |
2315 | * @ctx: audit context | |
2316 | * @gfp_mask: type of allocation | |
2317 | * @type: audit message type | |
2318 | * @fmt: format string to use | |
2319 | * @...: variable parameters matching the format string | |
2320 | * | |
2321 | * This is a convenience function that calls audit_log_start, | |
2322 | * audit_log_vformat, and audit_log_end. It may be called | |
2323 | * in any context. | |
2324 | */ | |
2325 | void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type, | |
2326 | const char *fmt, ...) | |
2327 | { | |
2328 | struct audit_buffer *ab; | |
2329 | va_list args; | |
2330 | ||
2331 | ab = audit_log_start(ctx, gfp_mask, type); | |
2332 | if (ab) { | |
2333 | va_start(args, fmt); | |
2334 | audit_log_vformat(ab, fmt, args); | |
2335 | va_end(args); | |
2336 | audit_log_end(ab); | |
2337 | } | |
2338 | } | |
2339 | ||
2340 | #ifdef CONFIG_SECURITY | |
2341 | /** | |
2342 | * audit_log_secctx - Converts and logs SELinux context | |
2343 | * @ab: audit_buffer | |
2344 | * @secid: security number | |
2345 | * | |
2346 | * This is a helper function that calls security_secid_to_secctx to convert | |
2347 | * secid to secctx and then adds the (converted) SELinux context to the audit | |
2348 | * log by calling audit_log_format, thus also preventing leak of internal secid | |
2349 | * to userspace. If secid cannot be converted audit_panic is called. | |
2350 | */ | |
2351 | void audit_log_secctx(struct audit_buffer *ab, u32 secid) | |
2352 | { | |
2353 | u32 len; | |
2354 | char *secctx; | |
2355 | ||
2356 | if (security_secid_to_secctx(secid, &secctx, &len)) { | |
2357 | audit_panic("Cannot convert secid to context"); | |
2358 | } else { | |
2359 | audit_log_format(ab, " obj=%s", secctx); | |
2360 | security_release_secctx(secctx, len); | |
2361 | } | |
2362 | } | |
2363 | EXPORT_SYMBOL(audit_log_secctx); | |
2364 | #endif | |
2365 | ||
2366 | EXPORT_SYMBOL(audit_log_start); | |
2367 | EXPORT_SYMBOL(audit_log_end); | |
2368 | EXPORT_SYMBOL(audit_log_format); | |
2369 | EXPORT_SYMBOL(audit_log); |