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