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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 | * Audit userspace, documentation, tests, and bug/issue trackers: | |
42 | * https://github.com/linux-audit | |
43 | */ | |
44 | ||
45 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
46 | ||
47 | #include <linux/file.h> | |
48 | #include <linux/init.h> | |
49 | #include <linux/types.h> | |
50 | #include <linux/atomic.h> | |
51 | #include <linux/mm.h> | |
52 | #include <linux/export.h> | |
53 | #include <linux/slab.h> | |
54 | #include <linux/err.h> | |
55 | #include <linux/kthread.h> | |
56 | #include <linux/kernel.h> | |
57 | #include <linux/syscalls.h> | |
58 | #include <linux/spinlock.h> | |
59 | #include <linux/rcupdate.h> | |
60 | #include <linux/mutex.h> | |
61 | #include <linux/gfp.h> | |
62 | #include <linux/pid.h> | |
63 | #include <linux/slab.h> | |
64 | ||
65 | #include <linux/audit.h> | |
66 | ||
67 | #include <net/sock.h> | |
68 | #include <net/netlink.h> | |
69 | #include <linux/skbuff.h> | |
70 | #ifdef CONFIG_SECURITY | |
71 | #include <linux/security.h> | |
72 | #endif | |
73 | #include <linux/freezer.h> | |
74 | #include <linux/pid_namespace.h> | |
75 | #include <net/netns/generic.h> | |
76 | ||
77 | #include "audit.h" | |
78 | ||
79 | /* No auditing will take place until audit_initialized == AUDIT_INITIALIZED. | |
80 | * (Initialization happens after skb_init is called.) */ | |
81 | #define AUDIT_DISABLED -1 | |
82 | #define AUDIT_UNINITIALIZED 0 | |
83 | #define AUDIT_INITIALIZED 1 | |
84 | static int audit_initialized; | |
85 | ||
86 | #define AUDIT_OFF 0 | |
87 | #define AUDIT_ON 1 | |
88 | #define AUDIT_LOCKED 2 | |
89 | u32 audit_enabled = AUDIT_OFF; | |
90 | bool audit_ever_enabled = !!AUDIT_OFF; | |
91 | ||
92 | EXPORT_SYMBOL_GPL(audit_enabled); | |
93 | ||
94 | /* Default state when kernel boots without any parameters. */ | |
95 | static u32 audit_default = AUDIT_OFF; | |
96 | ||
97 | /* If auditing cannot proceed, audit_failure selects what happens. */ | |
98 | static u32 audit_failure = AUDIT_FAIL_PRINTK; | |
99 | ||
100 | /* private audit network namespace index */ | |
101 | static unsigned int audit_net_id; | |
102 | ||
103 | /** | |
104 | * struct audit_net - audit private network namespace data | |
105 | * @sk: communication socket | |
106 | */ | |
107 | struct audit_net { | |
108 | struct sock *sk; | |
109 | }; | |
110 | ||
111 | /** | |
112 | * struct auditd_connection - kernel/auditd connection state | |
113 | * @pid: auditd PID | |
114 | * @portid: netlink portid | |
115 | * @net: the associated network namespace | |
116 | * @rcu: RCU head | |
117 | * | |
118 | * Description: | |
119 | * This struct is RCU protected; you must either hold the RCU lock for reading | |
120 | * or the associated spinlock for writing. | |
121 | */ | |
122 | static struct auditd_connection { | |
123 | struct pid *pid; | |
124 | u32 portid; | |
125 | struct net *net; | |
126 | struct rcu_head rcu; | |
127 | } *auditd_conn = NULL; | |
128 | static DEFINE_SPINLOCK(auditd_conn_lock); | |
129 | ||
130 | /* If audit_rate_limit is non-zero, limit the rate of sending audit records | |
131 | * to that number per second. This prevents DoS attacks, but results in | |
132 | * audit records being dropped. */ | |
133 | static u32 audit_rate_limit; | |
134 | ||
135 | /* Number of outstanding audit_buffers allowed. | |
136 | * When set to zero, this means unlimited. */ | |
137 | static u32 audit_backlog_limit = 64; | |
138 | #define AUDIT_BACKLOG_WAIT_TIME (60 * HZ) | |
139 | static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME; | |
140 | ||
141 | /* The identity of the user shutting down the audit system. */ | |
142 | kuid_t audit_sig_uid = INVALID_UID; | |
143 | pid_t audit_sig_pid = -1; | |
144 | u32 audit_sig_sid = 0; | |
145 | ||
146 | /* Records can be lost in several ways: | |
147 | 0) [suppressed in audit_alloc] | |
148 | 1) out of memory in audit_log_start [kmalloc of struct audit_buffer] | |
149 | 2) out of memory in audit_log_move [alloc_skb] | |
150 | 3) suppressed due to audit_rate_limit | |
151 | 4) suppressed due to audit_backlog_limit | |
152 | */ | |
153 | static atomic_t audit_lost = ATOMIC_INIT(0); | |
154 | ||
155 | /* Hash for inode-based rules */ | |
156 | struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS]; | |
157 | ||
158 | static struct kmem_cache *audit_buffer_cache; | |
159 | ||
160 | /* queue msgs to send via kauditd_task */ | |
161 | static struct sk_buff_head audit_queue; | |
162 | /* queue msgs due to temporary unicast send problems */ | |
163 | static struct sk_buff_head audit_retry_queue; | |
164 | /* queue msgs waiting for new auditd connection */ | |
165 | static struct sk_buff_head audit_hold_queue; | |
166 | ||
167 | /* queue servicing thread */ | |
168 | static struct task_struct *kauditd_task; | |
169 | static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait); | |
170 | ||
171 | /* waitqueue for callers who are blocked on the audit backlog */ | |
172 | static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait); | |
173 | ||
174 | static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION, | |
175 | .mask = -1, | |
176 | .features = 0, | |
177 | .lock = 0,}; | |
178 | ||
179 | static char *audit_feature_names[2] = { | |
180 | "only_unset_loginuid", | |
181 | "loginuid_immutable", | |
182 | }; | |
183 | ||
184 | /** | |
185 | * struct audit_ctl_mutex - serialize requests from userspace | |
186 | * @lock: the mutex used for locking | |
187 | * @owner: the task which owns the lock | |
188 | * | |
189 | * Description: | |
190 | * This is the lock struct used to ensure we only process userspace requests | |
191 | * in an orderly fashion. We can't simply use a mutex/lock here because we | |
192 | * need to track lock ownership so we don't end up blocking the lock owner in | |
193 | * audit_log_start() or similar. | |
194 | */ | |
195 | static struct audit_ctl_mutex { | |
196 | struct mutex lock; | |
197 | void *owner; | |
198 | } audit_cmd_mutex; | |
199 | ||
200 | /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting | |
201 | * audit records. Since printk uses a 1024 byte buffer, this buffer | |
202 | * should be at least that large. */ | |
203 | #define AUDIT_BUFSIZ 1024 | |
204 | ||
205 | /* The audit_buffer is used when formatting an audit record. The caller | |
206 | * locks briefly to get the record off the freelist or to allocate the | |
207 | * buffer, and locks briefly to send the buffer to the netlink layer or | |
208 | * to place it on a transmit queue. Multiple audit_buffers can be in | |
209 | * use simultaneously. */ | |
210 | struct audit_buffer { | |
211 | struct sk_buff *skb; /* formatted skb ready to send */ | |
212 | struct audit_context *ctx; /* NULL or associated context */ | |
213 | gfp_t gfp_mask; | |
214 | }; | |
215 | ||
216 | struct audit_reply { | |
217 | __u32 portid; | |
218 | struct net *net; | |
219 | struct sk_buff *skb; | |
220 | }; | |
221 | ||
222 | /** | |
223 | * auditd_test_task - Check to see if a given task is an audit daemon | |
224 | * @task: the task to check | |
225 | * | |
226 | * Description: | |
227 | * Return 1 if the task is a registered audit daemon, 0 otherwise. | |
228 | */ | |
229 | int auditd_test_task(struct task_struct *task) | |
230 | { | |
231 | int rc; | |
232 | struct auditd_connection *ac; | |
233 | ||
234 | rcu_read_lock(); | |
235 | ac = rcu_dereference(auditd_conn); | |
236 | rc = (ac && ac->pid == task_tgid(task) ? 1 : 0); | |
237 | rcu_read_unlock(); | |
238 | ||
239 | return rc; | |
240 | } | |
241 | ||
242 | /** | |
243 | * audit_ctl_lock - Take the audit control lock | |
244 | */ | |
245 | void audit_ctl_lock(void) | |
246 | { | |
247 | mutex_lock(&audit_cmd_mutex.lock); | |
248 | audit_cmd_mutex.owner = current; | |
249 | } | |
250 | ||
251 | /** | |
252 | * audit_ctl_unlock - Drop the audit control lock | |
253 | */ | |
254 | void audit_ctl_unlock(void) | |
255 | { | |
256 | audit_cmd_mutex.owner = NULL; | |
257 | mutex_unlock(&audit_cmd_mutex.lock); | |
258 | } | |
259 | ||
260 | /** | |
261 | * audit_ctl_owner_current - Test to see if the current task owns the lock | |
262 | * | |
263 | * Description: | |
264 | * Return true if the current task owns the audit control lock, false if it | |
265 | * doesn't own the lock. | |
266 | */ | |
267 | static bool audit_ctl_owner_current(void) | |
268 | { | |
269 | return (current == audit_cmd_mutex.owner); | |
270 | } | |
271 | ||
272 | /** | |
273 | * auditd_pid_vnr - Return the auditd PID relative to the namespace | |
274 | * | |
275 | * Description: | |
276 | * Returns the PID in relation to the namespace, 0 on failure. | |
277 | */ | |
278 | static pid_t auditd_pid_vnr(void) | |
279 | { | |
280 | pid_t pid; | |
281 | const struct auditd_connection *ac; | |
282 | ||
283 | rcu_read_lock(); | |
284 | ac = rcu_dereference(auditd_conn); | |
285 | if (!ac || !ac->pid) | |
286 | pid = 0; | |
287 | else | |
288 | pid = pid_vnr(ac->pid); | |
289 | rcu_read_unlock(); | |
290 | ||
291 | return pid; | |
292 | } | |
293 | ||
294 | /** | |
295 | * audit_get_sk - Return the audit socket for the given network namespace | |
296 | * @net: the destination network namespace | |
297 | * | |
298 | * Description: | |
299 | * Returns the sock pointer if valid, NULL otherwise. The caller must ensure | |
300 | * that a reference is held for the network namespace while the sock is in use. | |
301 | */ | |
302 | static struct sock *audit_get_sk(const struct net *net) | |
303 | { | |
304 | struct audit_net *aunet; | |
305 | ||
306 | if (!net) | |
307 | return NULL; | |
308 | ||
309 | aunet = net_generic(net, audit_net_id); | |
310 | return aunet->sk; | |
311 | } | |
312 | ||
313 | void audit_panic(const char *message) | |
314 | { | |
315 | switch (audit_failure) { | |
316 | case AUDIT_FAIL_SILENT: | |
317 | break; | |
318 | case AUDIT_FAIL_PRINTK: | |
319 | if (printk_ratelimit()) | |
320 | pr_err("%s\n", message); | |
321 | break; | |
322 | case AUDIT_FAIL_PANIC: | |
323 | panic("audit: %s\n", message); | |
324 | break; | |
325 | } | |
326 | } | |
327 | ||
328 | static inline int audit_rate_check(void) | |
329 | { | |
330 | static unsigned long last_check = 0; | |
331 | static int messages = 0; | |
332 | static DEFINE_SPINLOCK(lock); | |
333 | unsigned long flags; | |
334 | unsigned long now; | |
335 | unsigned long elapsed; | |
336 | int retval = 0; | |
337 | ||
338 | if (!audit_rate_limit) return 1; | |
339 | ||
340 | spin_lock_irqsave(&lock, flags); | |
341 | if (++messages < audit_rate_limit) { | |
342 | retval = 1; | |
343 | } else { | |
344 | now = jiffies; | |
345 | elapsed = now - last_check; | |
346 | if (elapsed > HZ) { | |
347 | last_check = now; | |
348 | messages = 0; | |
349 | retval = 1; | |
350 | } | |
351 | } | |
352 | spin_unlock_irqrestore(&lock, flags); | |
353 | ||
354 | return retval; | |
355 | } | |
356 | ||
357 | /** | |
358 | * audit_log_lost - conditionally log lost audit message event | |
359 | * @message: the message stating reason for lost audit message | |
360 | * | |
361 | * Emit at least 1 message per second, even if audit_rate_check is | |
362 | * throttling. | |
363 | * Always increment the lost messages counter. | |
364 | */ | |
365 | void audit_log_lost(const char *message) | |
366 | { | |
367 | static unsigned long last_msg = 0; | |
368 | static DEFINE_SPINLOCK(lock); | |
369 | unsigned long flags; | |
370 | unsigned long now; | |
371 | int print; | |
372 | ||
373 | atomic_inc(&audit_lost); | |
374 | ||
375 | print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit); | |
376 | ||
377 | if (!print) { | |
378 | spin_lock_irqsave(&lock, flags); | |
379 | now = jiffies; | |
380 | if (now - last_msg > HZ) { | |
381 | print = 1; | |
382 | last_msg = now; | |
383 | } | |
384 | spin_unlock_irqrestore(&lock, flags); | |
385 | } | |
386 | ||
387 | if (print) { | |
388 | if (printk_ratelimit()) | |
389 | pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n", | |
390 | atomic_read(&audit_lost), | |
391 | audit_rate_limit, | |
392 | audit_backlog_limit); | |
393 | audit_panic(message); | |
394 | } | |
395 | } | |
396 | ||
397 | static int audit_log_config_change(char *function_name, u32 new, u32 old, | |
398 | int allow_changes) | |
399 | { | |
400 | struct audit_buffer *ab; | |
401 | int rc = 0; | |
402 | ||
403 | ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE); | |
404 | if (unlikely(!ab)) | |
405 | return rc; | |
406 | audit_log_format(ab, "%s=%u old=%u", function_name, new, old); | |
407 | audit_log_session_info(ab); | |
408 | rc = audit_log_task_context(ab); | |
409 | if (rc) | |
410 | allow_changes = 0; /* Something weird, deny request */ | |
411 | audit_log_format(ab, " res=%d", allow_changes); | |
412 | audit_log_end(ab); | |
413 | return rc; | |
414 | } | |
415 | ||
416 | static int audit_do_config_change(char *function_name, u32 *to_change, u32 new) | |
417 | { | |
418 | int allow_changes, rc = 0; | |
419 | u32 old = *to_change; | |
420 | ||
421 | /* check if we are locked */ | |
422 | if (audit_enabled == AUDIT_LOCKED) | |
423 | allow_changes = 0; | |
424 | else | |
425 | allow_changes = 1; | |
426 | ||
427 | if (audit_enabled != AUDIT_OFF) { | |
428 | rc = audit_log_config_change(function_name, new, old, allow_changes); | |
429 | if (rc) | |
430 | allow_changes = 0; | |
431 | } | |
432 | ||
433 | /* If we are allowed, make the change */ | |
434 | if (allow_changes == 1) | |
435 | *to_change = new; | |
436 | /* Not allowed, update reason */ | |
437 | else if (rc == 0) | |
438 | rc = -EPERM; | |
439 | return rc; | |
440 | } | |
441 | ||
442 | static int audit_set_rate_limit(u32 limit) | |
443 | { | |
444 | return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit); | |
445 | } | |
446 | ||
447 | static int audit_set_backlog_limit(u32 limit) | |
448 | { | |
449 | return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit); | |
450 | } | |
451 | ||
452 | static int audit_set_backlog_wait_time(u32 timeout) | |
453 | { | |
454 | return audit_do_config_change("audit_backlog_wait_time", | |
455 | &audit_backlog_wait_time, timeout); | |
456 | } | |
457 | ||
458 | static int audit_set_enabled(u32 state) | |
459 | { | |
460 | int rc; | |
461 | if (state > AUDIT_LOCKED) | |
462 | return -EINVAL; | |
463 | ||
464 | rc = audit_do_config_change("audit_enabled", &audit_enabled, state); | |
465 | if (!rc) | |
466 | audit_ever_enabled |= !!state; | |
467 | ||
468 | return rc; | |
469 | } | |
470 | ||
471 | static int audit_set_failure(u32 state) | |
472 | { | |
473 | if (state != AUDIT_FAIL_SILENT | |
474 | && state != AUDIT_FAIL_PRINTK | |
475 | && state != AUDIT_FAIL_PANIC) | |
476 | return -EINVAL; | |
477 | ||
478 | return audit_do_config_change("audit_failure", &audit_failure, state); | |
479 | } | |
480 | ||
481 | /** | |
482 | * auditd_conn_free - RCU helper to release an auditd connection struct | |
483 | * @rcu: RCU head | |
484 | * | |
485 | * Description: | |
486 | * Drop any references inside the auditd connection tracking struct and free | |
487 | * the memory. | |
488 | */ | |
489 | static void auditd_conn_free(struct rcu_head *rcu) | |
490 | { | |
491 | struct auditd_connection *ac; | |
492 | ||
493 | ac = container_of(rcu, struct auditd_connection, rcu); | |
494 | put_pid(ac->pid); | |
495 | put_net(ac->net); | |
496 | kfree(ac); | |
497 | } | |
498 | ||
499 | /** | |
500 | * auditd_set - Set/Reset the auditd connection state | |
501 | * @pid: auditd PID | |
502 | * @portid: auditd netlink portid | |
503 | * @net: auditd network namespace pointer | |
504 | * | |
505 | * Description: | |
506 | * This function will obtain and drop network namespace references as | |
507 | * necessary. Returns zero on success, negative values on failure. | |
508 | */ | |
509 | static int auditd_set(struct pid *pid, u32 portid, struct net *net) | |
510 | { | |
511 | unsigned long flags; | |
512 | struct auditd_connection *ac_old, *ac_new; | |
513 | ||
514 | if (!pid || !net) | |
515 | return -EINVAL; | |
516 | ||
517 | ac_new = kzalloc(sizeof(*ac_new), GFP_KERNEL); | |
518 | if (!ac_new) | |
519 | return -ENOMEM; | |
520 | ac_new->pid = get_pid(pid); | |
521 | ac_new->portid = portid; | |
522 | ac_new->net = get_net(net); | |
523 | ||
524 | spin_lock_irqsave(&auditd_conn_lock, flags); | |
525 | ac_old = rcu_dereference_protected(auditd_conn, | |
526 | lockdep_is_held(&auditd_conn_lock)); | |
527 | rcu_assign_pointer(auditd_conn, ac_new); | |
528 | spin_unlock_irqrestore(&auditd_conn_lock, flags); | |
529 | ||
530 | if (ac_old) | |
531 | call_rcu(&ac_old->rcu, auditd_conn_free); | |
532 | ||
533 | return 0; | |
534 | } | |
535 | ||
536 | /** | |
537 | * kauditd_print_skb - Print the audit record to the ring buffer | |
538 | * @skb: audit record | |
539 | * | |
540 | * Whatever the reason, this packet may not make it to the auditd connection | |
541 | * so write it via printk so the information isn't completely lost. | |
542 | */ | |
543 | static void kauditd_printk_skb(struct sk_buff *skb) | |
544 | { | |
545 | struct nlmsghdr *nlh = nlmsg_hdr(skb); | |
546 | char *data = nlmsg_data(nlh); | |
547 | ||
548 | if (nlh->nlmsg_type != AUDIT_EOE && printk_ratelimit()) | |
549 | pr_notice("type=%d %s\n", nlh->nlmsg_type, data); | |
550 | } | |
551 | ||
552 | /** | |
553 | * kauditd_rehold_skb - Handle a audit record send failure in the hold queue | |
554 | * @skb: audit record | |
555 | * | |
556 | * Description: | |
557 | * This should only be used by the kauditd_thread when it fails to flush the | |
558 | * hold queue. | |
559 | */ | |
560 | static void kauditd_rehold_skb(struct sk_buff *skb) | |
561 | { | |
562 | /* put the record back in the queue at the same place */ | |
563 | skb_queue_head(&audit_hold_queue, skb); | |
564 | } | |
565 | ||
566 | /** | |
567 | * kauditd_hold_skb - Queue an audit record, waiting for auditd | |
568 | * @skb: audit record | |
569 | * | |
570 | * Description: | |
571 | * Queue the audit record, waiting for an instance of auditd. When this | |
572 | * function is called we haven't given up yet on sending the record, but things | |
573 | * are not looking good. The first thing we want to do is try to write the | |
574 | * record via printk and then see if we want to try and hold on to the record | |
575 | * and queue it, if we have room. If we want to hold on to the record, but we | |
576 | * don't have room, record a record lost message. | |
577 | */ | |
578 | static void kauditd_hold_skb(struct sk_buff *skb) | |
579 | { | |
580 | /* at this point it is uncertain if we will ever send this to auditd so | |
581 | * try to send the message via printk before we go any further */ | |
582 | kauditd_printk_skb(skb); | |
583 | ||
584 | /* can we just silently drop the message? */ | |
585 | if (!audit_default) { | |
586 | kfree_skb(skb); | |
587 | return; | |
588 | } | |
589 | ||
590 | /* if we have room, queue the message */ | |
591 | if (!audit_backlog_limit || | |
592 | skb_queue_len(&audit_hold_queue) < audit_backlog_limit) { | |
593 | skb_queue_tail(&audit_hold_queue, skb); | |
594 | return; | |
595 | } | |
596 | ||
597 | /* we have no other options - drop the message */ | |
598 | audit_log_lost("kauditd hold queue overflow"); | |
599 | kfree_skb(skb); | |
600 | } | |
601 | ||
602 | /** | |
603 | * kauditd_retry_skb - Queue an audit record, attempt to send again to auditd | |
604 | * @skb: audit record | |
605 | * | |
606 | * Description: | |
607 | * Not as serious as kauditd_hold_skb() as we still have a connected auditd, | |
608 | * but for some reason we are having problems sending it audit records so | |
609 | * queue the given record and attempt to resend. | |
610 | */ | |
611 | static void kauditd_retry_skb(struct sk_buff *skb) | |
612 | { | |
613 | /* NOTE: because records should only live in the retry queue for a | |
614 | * short period of time, before either being sent or moved to the hold | |
615 | * queue, we don't currently enforce a limit on this queue */ | |
616 | skb_queue_tail(&audit_retry_queue, skb); | |
617 | } | |
618 | ||
619 | /** | |
620 | * auditd_reset - Disconnect the auditd connection | |
621 | * @ac: auditd connection state | |
622 | * | |
623 | * Description: | |
624 | * Break the auditd/kauditd connection and move all the queued records into the | |
625 | * hold queue in case auditd reconnects. It is important to note that the @ac | |
626 | * pointer should never be dereferenced inside this function as it may be NULL | |
627 | * or invalid, you can only compare the memory address! If @ac is NULL then | |
628 | * the connection will always be reset. | |
629 | */ | |
630 | static void auditd_reset(const struct auditd_connection *ac) | |
631 | { | |
632 | unsigned long flags; | |
633 | struct sk_buff *skb; | |
634 | struct auditd_connection *ac_old; | |
635 | ||
636 | /* if it isn't already broken, break the connection */ | |
637 | spin_lock_irqsave(&auditd_conn_lock, flags); | |
638 | ac_old = rcu_dereference_protected(auditd_conn, | |
639 | lockdep_is_held(&auditd_conn_lock)); | |
640 | if (ac && ac != ac_old) { | |
641 | /* someone already registered a new auditd connection */ | |
642 | spin_unlock_irqrestore(&auditd_conn_lock, flags); | |
643 | return; | |
644 | } | |
645 | rcu_assign_pointer(auditd_conn, NULL); | |
646 | spin_unlock_irqrestore(&auditd_conn_lock, flags); | |
647 | ||
648 | if (ac_old) | |
649 | call_rcu(&ac_old->rcu, auditd_conn_free); | |
650 | ||
651 | /* flush the retry queue to the hold queue, but don't touch the main | |
652 | * queue since we need to process that normally for multicast */ | |
653 | while ((skb = skb_dequeue(&audit_retry_queue))) | |
654 | kauditd_hold_skb(skb); | |
655 | } | |
656 | ||
657 | /** | |
658 | * auditd_send_unicast_skb - Send a record via unicast to auditd | |
659 | * @skb: audit record | |
660 | * | |
661 | * Description: | |
662 | * Send a skb to the audit daemon, returns positive/zero values on success and | |
663 | * negative values on failure; in all cases the skb will be consumed by this | |
664 | * function. If the send results in -ECONNREFUSED the connection with auditd | |
665 | * will be reset. This function may sleep so callers should not hold any locks | |
666 | * where this would cause a problem. | |
667 | */ | |
668 | static int auditd_send_unicast_skb(struct sk_buff *skb) | |
669 | { | |
670 | int rc; | |
671 | u32 portid; | |
672 | struct net *net; | |
673 | struct sock *sk; | |
674 | struct auditd_connection *ac; | |
675 | ||
676 | /* NOTE: we can't call netlink_unicast while in the RCU section so | |
677 | * take a reference to the network namespace and grab local | |
678 | * copies of the namespace, the sock, and the portid; the | |
679 | * namespace and sock aren't going to go away while we hold a | |
680 | * reference and if the portid does become invalid after the RCU | |
681 | * section netlink_unicast() should safely return an error */ | |
682 | ||
683 | rcu_read_lock(); | |
684 | ac = rcu_dereference(auditd_conn); | |
685 | if (!ac) { | |
686 | rcu_read_unlock(); | |
687 | kfree_skb(skb); | |
688 | rc = -ECONNREFUSED; | |
689 | goto err; | |
690 | } | |
691 | net = get_net(ac->net); | |
692 | sk = audit_get_sk(net); | |
693 | portid = ac->portid; | |
694 | rcu_read_unlock(); | |
695 | ||
696 | rc = netlink_unicast(sk, skb, portid, 0); | |
697 | put_net(net); | |
698 | if (rc < 0) | |
699 | goto err; | |
700 | ||
701 | return rc; | |
702 | ||
703 | err: | |
704 | if (ac && rc == -ECONNREFUSED) | |
705 | auditd_reset(ac); | |
706 | return rc; | |
707 | } | |
708 | ||
709 | /** | |
710 | * kauditd_send_queue - Helper for kauditd_thread to flush skb queues | |
711 | * @sk: the sending sock | |
712 | * @portid: the netlink destination | |
713 | * @queue: the skb queue to process | |
714 | * @retry_limit: limit on number of netlink unicast failures | |
715 | * @skb_hook: per-skb hook for additional processing | |
716 | * @err_hook: hook called if the skb fails the netlink unicast send | |
717 | * | |
718 | * Description: | |
719 | * Run through the given queue and attempt to send the audit records to auditd, | |
720 | * returns zero on success, negative values on failure. It is up to the caller | |
721 | * to ensure that the @sk is valid for the duration of this function. | |
722 | * | |
723 | */ | |
724 | static int kauditd_send_queue(struct sock *sk, u32 portid, | |
725 | struct sk_buff_head *queue, | |
726 | unsigned int retry_limit, | |
727 | void (*skb_hook)(struct sk_buff *skb), | |
728 | void (*err_hook)(struct sk_buff *skb)) | |
729 | { | |
730 | int rc = 0; | |
731 | struct sk_buff *skb; | |
732 | static unsigned int failed = 0; | |
733 | ||
734 | /* NOTE: kauditd_thread takes care of all our locking, we just use | |
735 | * the netlink info passed to us (e.g. sk and portid) */ | |
736 | ||
737 | while ((skb = skb_dequeue(queue))) { | |
738 | /* call the skb_hook for each skb we touch */ | |
739 | if (skb_hook) | |
740 | (*skb_hook)(skb); | |
741 | ||
742 | /* can we send to anyone via unicast? */ | |
743 | if (!sk) { | |
744 | if (err_hook) | |
745 | (*err_hook)(skb); | |
746 | continue; | |
747 | } | |
748 | ||
749 | /* grab an extra skb reference in case of error */ | |
750 | skb_get(skb); | |
751 | rc = netlink_unicast(sk, skb, portid, 0); | |
752 | if (rc < 0) { | |
753 | /* fatal failure for our queue flush attempt? */ | |
754 | if (++failed >= retry_limit || | |
755 | rc == -ECONNREFUSED || rc == -EPERM) { | |
756 | /* yes - error processing for the queue */ | |
757 | sk = NULL; | |
758 | if (err_hook) | |
759 | (*err_hook)(skb); | |
760 | if (!skb_hook) | |
761 | goto out; | |
762 | /* keep processing with the skb_hook */ | |
763 | continue; | |
764 | } else | |
765 | /* no - requeue to preserve ordering */ | |
766 | skb_queue_head(queue, skb); | |
767 | } else { | |
768 | /* it worked - drop the extra reference and continue */ | |
769 | consume_skb(skb); | |
770 | failed = 0; | |
771 | } | |
772 | } | |
773 | ||
774 | out: | |
775 | return (rc >= 0 ? 0 : rc); | |
776 | } | |
777 | ||
778 | /* | |
779 | * kauditd_send_multicast_skb - Send a record to any multicast listeners | |
780 | * @skb: audit record | |
781 | * | |
782 | * Description: | |
783 | * Write a multicast message to anyone listening in the initial network | |
784 | * namespace. This function doesn't consume an skb as might be expected since | |
785 | * it has to copy it anyways. | |
786 | */ | |
787 | static void kauditd_send_multicast_skb(struct sk_buff *skb) | |
788 | { | |
789 | struct sk_buff *copy; | |
790 | struct sock *sock = audit_get_sk(&init_net); | |
791 | struct nlmsghdr *nlh; | |
792 | ||
793 | /* NOTE: we are not taking an additional reference for init_net since | |
794 | * we don't have to worry about it going away */ | |
795 | ||
796 | if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG)) | |
797 | return; | |
798 | ||
799 | /* | |
800 | * The seemingly wasteful skb_copy() rather than bumping the refcount | |
801 | * using skb_get() is necessary because non-standard mods are made to | |
802 | * the skb by the original kaudit unicast socket send routine. The | |
803 | * existing auditd daemon assumes this breakage. Fixing this would | |
804 | * require co-ordinating a change in the established protocol between | |
805 | * the kaudit kernel subsystem and the auditd userspace code. There is | |
806 | * no reason for new multicast clients to continue with this | |
807 | * non-compliance. | |
808 | */ | |
809 | copy = skb_copy(skb, GFP_KERNEL); | |
810 | if (!copy) | |
811 | return; | |
812 | nlh = nlmsg_hdr(copy); | |
813 | nlh->nlmsg_len = skb->len; | |
814 | ||
815 | nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL); | |
816 | } | |
817 | ||
818 | /** | |
819 | * kauditd_thread - Worker thread to send audit records to userspace | |
820 | * @dummy: unused | |
821 | */ | |
822 | static int kauditd_thread(void *dummy) | |
823 | { | |
824 | int rc; | |
825 | u32 portid = 0; | |
826 | struct net *net = NULL; | |
827 | struct sock *sk = NULL; | |
828 | struct auditd_connection *ac; | |
829 | ||
830 | #define UNICAST_RETRIES 5 | |
831 | ||
832 | set_freezable(); | |
833 | while (!kthread_should_stop()) { | |
834 | /* NOTE: see the lock comments in auditd_send_unicast_skb() */ | |
835 | rcu_read_lock(); | |
836 | ac = rcu_dereference(auditd_conn); | |
837 | if (!ac) { | |
838 | rcu_read_unlock(); | |
839 | goto main_queue; | |
840 | } | |
841 | net = get_net(ac->net); | |
842 | sk = audit_get_sk(net); | |
843 | portid = ac->portid; | |
844 | rcu_read_unlock(); | |
845 | ||
846 | /* attempt to flush the hold queue */ | |
847 | rc = kauditd_send_queue(sk, portid, | |
848 | &audit_hold_queue, UNICAST_RETRIES, | |
849 | NULL, kauditd_rehold_skb); | |
850 | if (ac && rc < 0) { | |
851 | sk = NULL; | |
852 | auditd_reset(ac); | |
853 | goto main_queue; | |
854 | } | |
855 | ||
856 | /* attempt to flush the retry queue */ | |
857 | rc = kauditd_send_queue(sk, portid, | |
858 | &audit_retry_queue, UNICAST_RETRIES, | |
859 | NULL, kauditd_hold_skb); | |
860 | if (ac && rc < 0) { | |
861 | sk = NULL; | |
862 | auditd_reset(ac); | |
863 | goto main_queue; | |
864 | } | |
865 | ||
866 | main_queue: | |
867 | /* process the main queue - do the multicast send and attempt | |
868 | * unicast, dump failed record sends to the retry queue; if | |
869 | * sk == NULL due to previous failures we will just do the | |
870 | * multicast send and move the record to the hold queue */ | |
871 | rc = kauditd_send_queue(sk, portid, &audit_queue, 1, | |
872 | kauditd_send_multicast_skb, | |
873 | (sk ? | |
874 | kauditd_retry_skb : kauditd_hold_skb)); | |
875 | if (ac && rc < 0) | |
876 | auditd_reset(ac); | |
877 | sk = NULL; | |
878 | ||
879 | /* drop our netns reference, no auditd sends past this line */ | |
880 | if (net) { | |
881 | put_net(net); | |
882 | net = NULL; | |
883 | } | |
884 | ||
885 | /* we have processed all the queues so wake everyone */ | |
886 | wake_up(&audit_backlog_wait); | |
887 | ||
888 | /* NOTE: we want to wake up if there is anything on the queue, | |
889 | * regardless of if an auditd is connected, as we need to | |
890 | * do the multicast send and rotate records from the | |
891 | * main queue to the retry/hold queues */ | |
892 | wait_event_freezable(kauditd_wait, | |
893 | (skb_queue_len(&audit_queue) ? 1 : 0)); | |
894 | } | |
895 | ||
896 | return 0; | |
897 | } | |
898 | ||
899 | int audit_send_list(void *_dest) | |
900 | { | |
901 | struct audit_netlink_list *dest = _dest; | |
902 | struct sk_buff *skb; | |
903 | struct sock *sk = audit_get_sk(dest->net); | |
904 | ||
905 | /* wait for parent to finish and send an ACK */ | |
906 | audit_ctl_lock(); | |
907 | audit_ctl_unlock(); | |
908 | ||
909 | while ((skb = __skb_dequeue(&dest->q)) != NULL) | |
910 | netlink_unicast(sk, skb, dest->portid, 0); | |
911 | ||
912 | put_net(dest->net); | |
913 | kfree(dest); | |
914 | ||
915 | return 0; | |
916 | } | |
917 | ||
918 | struct sk_buff *audit_make_reply(int seq, int type, int done, | |
919 | int multi, const void *payload, int size) | |
920 | { | |
921 | struct sk_buff *skb; | |
922 | struct nlmsghdr *nlh; | |
923 | void *data; | |
924 | int flags = multi ? NLM_F_MULTI : 0; | |
925 | int t = done ? NLMSG_DONE : type; | |
926 | ||
927 | skb = nlmsg_new(size, GFP_KERNEL); | |
928 | if (!skb) | |
929 | return NULL; | |
930 | ||
931 | nlh = nlmsg_put(skb, 0, seq, t, size, flags); | |
932 | if (!nlh) | |
933 | goto out_kfree_skb; | |
934 | data = nlmsg_data(nlh); | |
935 | memcpy(data, payload, size); | |
936 | return skb; | |
937 | ||
938 | out_kfree_skb: | |
939 | kfree_skb(skb); | |
940 | return NULL; | |
941 | } | |
942 | ||
943 | static int audit_send_reply_thread(void *arg) | |
944 | { | |
945 | struct audit_reply *reply = (struct audit_reply *)arg; | |
946 | struct sock *sk = audit_get_sk(reply->net); | |
947 | ||
948 | audit_ctl_lock(); | |
949 | audit_ctl_unlock(); | |
950 | ||
951 | /* Ignore failure. It'll only happen if the sender goes away, | |
952 | because our timeout is set to infinite. */ | |
953 | netlink_unicast(sk, reply->skb, reply->portid, 0); | |
954 | put_net(reply->net); | |
955 | kfree(reply); | |
956 | return 0; | |
957 | } | |
958 | ||
959 | /** | |
960 | * audit_send_reply - send an audit reply message via netlink | |
961 | * @request_skb: skb of request we are replying to (used to target the reply) | |
962 | * @seq: sequence number | |
963 | * @type: audit message type | |
964 | * @done: done (last) flag | |
965 | * @multi: multi-part message flag | |
966 | * @payload: payload data | |
967 | * @size: payload size | |
968 | * | |
969 | * Allocates an skb, builds the netlink message, and sends it to the port id. | |
970 | * No failure notifications. | |
971 | */ | |
972 | static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done, | |
973 | int multi, const void *payload, int size) | |
974 | { | |
975 | struct net *net = sock_net(NETLINK_CB(request_skb).sk); | |
976 | struct sk_buff *skb; | |
977 | struct task_struct *tsk; | |
978 | struct audit_reply *reply = kmalloc(sizeof(struct audit_reply), | |
979 | GFP_KERNEL); | |
980 | ||
981 | if (!reply) | |
982 | return; | |
983 | ||
984 | skb = audit_make_reply(seq, type, done, multi, payload, size); | |
985 | if (!skb) | |
986 | goto out; | |
987 | ||
988 | reply->net = get_net(net); | |
989 | reply->portid = NETLINK_CB(request_skb).portid; | |
990 | reply->skb = skb; | |
991 | ||
992 | tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply"); | |
993 | if (!IS_ERR(tsk)) | |
994 | return; | |
995 | kfree_skb(skb); | |
996 | out: | |
997 | kfree(reply); | |
998 | } | |
999 | ||
1000 | /* | |
1001 | * Check for appropriate CAP_AUDIT_ capabilities on incoming audit | |
1002 | * control messages. | |
1003 | */ | |
1004 | static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type) | |
1005 | { | |
1006 | int err = 0; | |
1007 | ||
1008 | /* Only support initial user namespace for now. */ | |
1009 | /* | |
1010 | * We return ECONNREFUSED because it tricks userspace into thinking | |
1011 | * that audit was not configured into the kernel. Lots of users | |
1012 | * configure their PAM stack (because that's what the distro does) | |
1013 | * to reject login if unable to send messages to audit. If we return | |
1014 | * ECONNREFUSED the PAM stack thinks the kernel does not have audit | |
1015 | * configured in and will let login proceed. If we return EPERM | |
1016 | * userspace will reject all logins. This should be removed when we | |
1017 | * support non init namespaces!! | |
1018 | */ | |
1019 | if (current_user_ns() != &init_user_ns) | |
1020 | return -ECONNREFUSED; | |
1021 | ||
1022 | switch (msg_type) { | |
1023 | case AUDIT_LIST: | |
1024 | case AUDIT_ADD: | |
1025 | case AUDIT_DEL: | |
1026 | return -EOPNOTSUPP; | |
1027 | case AUDIT_GET: | |
1028 | case AUDIT_SET: | |
1029 | case AUDIT_GET_FEATURE: | |
1030 | case AUDIT_SET_FEATURE: | |
1031 | case AUDIT_LIST_RULES: | |
1032 | case AUDIT_ADD_RULE: | |
1033 | case AUDIT_DEL_RULE: | |
1034 | case AUDIT_SIGNAL_INFO: | |
1035 | case AUDIT_TTY_GET: | |
1036 | case AUDIT_TTY_SET: | |
1037 | case AUDIT_TRIM: | |
1038 | case AUDIT_MAKE_EQUIV: | |
1039 | /* Only support auditd and auditctl in initial pid namespace | |
1040 | * for now. */ | |
1041 | if (task_active_pid_ns(current) != &init_pid_ns) | |
1042 | return -EPERM; | |
1043 | ||
1044 | if (!netlink_capable(skb, CAP_AUDIT_CONTROL)) | |
1045 | err = -EPERM; | |
1046 | break; | |
1047 | case AUDIT_USER: | |
1048 | case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG: | |
1049 | case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2: | |
1050 | if (!netlink_capable(skb, CAP_AUDIT_WRITE)) | |
1051 | err = -EPERM; | |
1052 | break; | |
1053 | default: /* bad msg */ | |
1054 | err = -EINVAL; | |
1055 | } | |
1056 | ||
1057 | return err; | |
1058 | } | |
1059 | ||
1060 | static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type) | |
1061 | { | |
1062 | uid_t uid = from_kuid(&init_user_ns, current_uid()); | |
1063 | pid_t pid = task_tgid_nr(current); | |
1064 | ||
1065 | if (!audit_enabled && msg_type != AUDIT_USER_AVC) { | |
1066 | *ab = NULL; | |
1067 | return; | |
1068 | } | |
1069 | ||
1070 | *ab = audit_log_start(NULL, GFP_KERNEL, msg_type); | |
1071 | if (unlikely(!*ab)) | |
1072 | return; | |
1073 | audit_log_format(*ab, "pid=%d uid=%u", pid, uid); | |
1074 | audit_log_session_info(*ab); | |
1075 | audit_log_task_context(*ab); | |
1076 | } | |
1077 | ||
1078 | int is_audit_feature_set(int i) | |
1079 | { | |
1080 | return af.features & AUDIT_FEATURE_TO_MASK(i); | |
1081 | } | |
1082 | ||
1083 | ||
1084 | static int audit_get_feature(struct sk_buff *skb) | |
1085 | { | |
1086 | u32 seq; | |
1087 | ||
1088 | seq = nlmsg_hdr(skb)->nlmsg_seq; | |
1089 | ||
1090 | audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af)); | |
1091 | ||
1092 | return 0; | |
1093 | } | |
1094 | ||
1095 | static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature, | |
1096 | u32 old_lock, u32 new_lock, int res) | |
1097 | { | |
1098 | struct audit_buffer *ab; | |
1099 | ||
1100 | if (audit_enabled == AUDIT_OFF) | |
1101 | return; | |
1102 | ||
1103 | ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_FEATURE_CHANGE); | |
1104 | if (!ab) | |
1105 | return; | |
1106 | audit_log_task_info(ab, current); | |
1107 | audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d", | |
1108 | audit_feature_names[which], !!old_feature, !!new_feature, | |
1109 | !!old_lock, !!new_lock, res); | |
1110 | audit_log_end(ab); | |
1111 | } | |
1112 | ||
1113 | static int audit_set_feature(struct sk_buff *skb) | |
1114 | { | |
1115 | struct audit_features *uaf; | |
1116 | int i; | |
1117 | ||
1118 | BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names)); | |
1119 | uaf = nlmsg_data(nlmsg_hdr(skb)); | |
1120 | ||
1121 | /* if there is ever a version 2 we should handle that here */ | |
1122 | ||
1123 | for (i = 0; i <= AUDIT_LAST_FEATURE; i++) { | |
1124 | u32 feature = AUDIT_FEATURE_TO_MASK(i); | |
1125 | u32 old_feature, new_feature, old_lock, new_lock; | |
1126 | ||
1127 | /* if we are not changing this feature, move along */ | |
1128 | if (!(feature & uaf->mask)) | |
1129 | continue; | |
1130 | ||
1131 | old_feature = af.features & feature; | |
1132 | new_feature = uaf->features & feature; | |
1133 | new_lock = (uaf->lock | af.lock) & feature; | |
1134 | old_lock = af.lock & feature; | |
1135 | ||
1136 | /* are we changing a locked feature? */ | |
1137 | if (old_lock && (new_feature != old_feature)) { | |
1138 | audit_log_feature_change(i, old_feature, new_feature, | |
1139 | old_lock, new_lock, 0); | |
1140 | return -EPERM; | |
1141 | } | |
1142 | } | |
1143 | /* nothing invalid, do the changes */ | |
1144 | for (i = 0; i <= AUDIT_LAST_FEATURE; i++) { | |
1145 | u32 feature = AUDIT_FEATURE_TO_MASK(i); | |
1146 | u32 old_feature, new_feature, old_lock, new_lock; | |
1147 | ||
1148 | /* if we are not changing this feature, move along */ | |
1149 | if (!(feature & uaf->mask)) | |
1150 | continue; | |
1151 | ||
1152 | old_feature = af.features & feature; | |
1153 | new_feature = uaf->features & feature; | |
1154 | old_lock = af.lock & feature; | |
1155 | new_lock = (uaf->lock | af.lock) & feature; | |
1156 | ||
1157 | if (new_feature != old_feature) | |
1158 | audit_log_feature_change(i, old_feature, new_feature, | |
1159 | old_lock, new_lock, 1); | |
1160 | ||
1161 | if (new_feature) | |
1162 | af.features |= feature; | |
1163 | else | |
1164 | af.features &= ~feature; | |
1165 | af.lock |= new_lock; | |
1166 | } | |
1167 | ||
1168 | return 0; | |
1169 | } | |
1170 | ||
1171 | static int audit_replace(struct pid *pid) | |
1172 | { | |
1173 | pid_t pvnr; | |
1174 | struct sk_buff *skb; | |
1175 | ||
1176 | pvnr = pid_vnr(pid); | |
1177 | skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pvnr, sizeof(pvnr)); | |
1178 | if (!skb) | |
1179 | return -ENOMEM; | |
1180 | return auditd_send_unicast_skb(skb); | |
1181 | } | |
1182 | ||
1183 | static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) | |
1184 | { | |
1185 | u32 seq; | |
1186 | void *data; | |
1187 | int err; | |
1188 | struct audit_buffer *ab; | |
1189 | u16 msg_type = nlh->nlmsg_type; | |
1190 | struct audit_sig_info *sig_data; | |
1191 | char *ctx = NULL; | |
1192 | u32 len; | |
1193 | ||
1194 | err = audit_netlink_ok(skb, msg_type); | |
1195 | if (err) | |
1196 | return err; | |
1197 | ||
1198 | seq = nlh->nlmsg_seq; | |
1199 | data = nlmsg_data(nlh); | |
1200 | ||
1201 | switch (msg_type) { | |
1202 | case AUDIT_GET: { | |
1203 | struct audit_status s; | |
1204 | memset(&s, 0, sizeof(s)); | |
1205 | s.enabled = audit_enabled; | |
1206 | s.failure = audit_failure; | |
1207 | /* NOTE: use pid_vnr() so the PID is relative to the current | |
1208 | * namespace */ | |
1209 | s.pid = auditd_pid_vnr(); | |
1210 | s.rate_limit = audit_rate_limit; | |
1211 | s.backlog_limit = audit_backlog_limit; | |
1212 | s.lost = atomic_read(&audit_lost); | |
1213 | s.backlog = skb_queue_len(&audit_queue); | |
1214 | s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL; | |
1215 | s.backlog_wait_time = audit_backlog_wait_time; | |
1216 | audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s)); | |
1217 | break; | |
1218 | } | |
1219 | case AUDIT_SET: { | |
1220 | struct audit_status s; | |
1221 | memset(&s, 0, sizeof(s)); | |
1222 | /* guard against past and future API changes */ | |
1223 | memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh))); | |
1224 | if (s.mask & AUDIT_STATUS_ENABLED) { | |
1225 | err = audit_set_enabled(s.enabled); | |
1226 | if (err < 0) | |
1227 | return err; | |
1228 | } | |
1229 | if (s.mask & AUDIT_STATUS_FAILURE) { | |
1230 | err = audit_set_failure(s.failure); | |
1231 | if (err < 0) | |
1232 | return err; | |
1233 | } | |
1234 | if (s.mask & AUDIT_STATUS_PID) { | |
1235 | /* NOTE: we are using the vnr PID functions below | |
1236 | * because the s.pid value is relative to the | |
1237 | * namespace of the caller; at present this | |
1238 | * doesn't matter much since you can really only | |
1239 | * run auditd from the initial pid namespace, but | |
1240 | * something to keep in mind if this changes */ | |
1241 | pid_t new_pid = s.pid; | |
1242 | pid_t auditd_pid; | |
1243 | struct pid *req_pid = task_tgid(current); | |
1244 | ||
1245 | /* Sanity check - PID values must match. Setting | |
1246 | * pid to 0 is how auditd ends auditing. */ | |
1247 | if (new_pid && (new_pid != pid_vnr(req_pid))) | |
1248 | return -EINVAL; | |
1249 | ||
1250 | /* test the auditd connection */ | |
1251 | audit_replace(req_pid); | |
1252 | ||
1253 | auditd_pid = auditd_pid_vnr(); | |
1254 | if (auditd_pid) { | |
1255 | /* replacing a healthy auditd is not allowed */ | |
1256 | if (new_pid) { | |
1257 | audit_log_config_change("audit_pid", | |
1258 | new_pid, auditd_pid, 0); | |
1259 | return -EEXIST; | |
1260 | } | |
1261 | /* only current auditd can unregister itself */ | |
1262 | if (pid_vnr(req_pid) != auditd_pid) { | |
1263 | audit_log_config_change("audit_pid", | |
1264 | new_pid, auditd_pid, 0); | |
1265 | return -EACCES; | |
1266 | } | |
1267 | } | |
1268 | ||
1269 | if (new_pid) { | |
1270 | /* register a new auditd connection */ | |
1271 | err = auditd_set(req_pid, | |
1272 | NETLINK_CB(skb).portid, | |
1273 | sock_net(NETLINK_CB(skb).sk)); | |
1274 | if (audit_enabled != AUDIT_OFF) | |
1275 | audit_log_config_change("audit_pid", | |
1276 | new_pid, | |
1277 | auditd_pid, | |
1278 | err ? 0 : 1); | |
1279 | if (err) | |
1280 | return err; | |
1281 | ||
1282 | /* try to process any backlog */ | |
1283 | wake_up_interruptible(&kauditd_wait); | |
1284 | } else { | |
1285 | if (audit_enabled != AUDIT_OFF) | |
1286 | audit_log_config_change("audit_pid", | |
1287 | new_pid, | |
1288 | auditd_pid, 1); | |
1289 | ||
1290 | /* unregister the auditd connection */ | |
1291 | auditd_reset(NULL); | |
1292 | } | |
1293 | } | |
1294 | if (s.mask & AUDIT_STATUS_RATE_LIMIT) { | |
1295 | err = audit_set_rate_limit(s.rate_limit); | |
1296 | if (err < 0) | |
1297 | return err; | |
1298 | } | |
1299 | if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) { | |
1300 | err = audit_set_backlog_limit(s.backlog_limit); | |
1301 | if (err < 0) | |
1302 | return err; | |
1303 | } | |
1304 | if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) { | |
1305 | if (sizeof(s) > (size_t)nlh->nlmsg_len) | |
1306 | return -EINVAL; | |
1307 | if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME) | |
1308 | return -EINVAL; | |
1309 | err = audit_set_backlog_wait_time(s.backlog_wait_time); | |
1310 | if (err < 0) | |
1311 | return err; | |
1312 | } | |
1313 | if (s.mask == AUDIT_STATUS_LOST) { | |
1314 | u32 lost = atomic_xchg(&audit_lost, 0); | |
1315 | ||
1316 | audit_log_config_change("lost", 0, lost, 1); | |
1317 | return lost; | |
1318 | } | |
1319 | break; | |
1320 | } | |
1321 | case AUDIT_GET_FEATURE: | |
1322 | err = audit_get_feature(skb); | |
1323 | if (err) | |
1324 | return err; | |
1325 | break; | |
1326 | case AUDIT_SET_FEATURE: | |
1327 | err = audit_set_feature(skb); | |
1328 | if (err) | |
1329 | return err; | |
1330 | break; | |
1331 | case AUDIT_USER: | |
1332 | case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG: | |
1333 | case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2: | |
1334 | if (!audit_enabled && msg_type != AUDIT_USER_AVC) | |
1335 | return 0; | |
1336 | ||
1337 | err = audit_filter(msg_type, AUDIT_FILTER_USER); | |
1338 | if (err == 1) { /* match or error */ | |
1339 | err = 0; | |
1340 | if (msg_type == AUDIT_USER_TTY) { | |
1341 | err = tty_audit_push(); | |
1342 | if (err) | |
1343 | break; | |
1344 | } | |
1345 | audit_log_common_recv_msg(&ab, msg_type); | |
1346 | if (msg_type != AUDIT_USER_TTY) | |
1347 | audit_log_format(ab, " msg='%.*s'", | |
1348 | AUDIT_MESSAGE_TEXT_MAX, | |
1349 | (char *)data); | |
1350 | else { | |
1351 | int size; | |
1352 | ||
1353 | audit_log_format(ab, " data="); | |
1354 | size = nlmsg_len(nlh); | |
1355 | if (size > 0 && | |
1356 | ((unsigned char *)data)[size - 1] == '\0') | |
1357 | size--; | |
1358 | audit_log_n_untrustedstring(ab, data, size); | |
1359 | } | |
1360 | audit_log_end(ab); | |
1361 | } | |
1362 | break; | |
1363 | case AUDIT_ADD_RULE: | |
1364 | case AUDIT_DEL_RULE: | |
1365 | if (nlmsg_len(nlh) < sizeof(struct audit_rule_data)) | |
1366 | return -EINVAL; | |
1367 | if (audit_enabled == AUDIT_LOCKED) { | |
1368 | audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE); | |
1369 | audit_log_format(ab, " audit_enabled=%d res=0", audit_enabled); | |
1370 | audit_log_end(ab); | |
1371 | return -EPERM; | |
1372 | } | |
1373 | err = audit_rule_change(msg_type, seq, data, nlmsg_len(nlh)); | |
1374 | break; | |
1375 | case AUDIT_LIST_RULES: | |
1376 | err = audit_list_rules_send(skb, seq); | |
1377 | break; | |
1378 | case AUDIT_TRIM: | |
1379 | audit_trim_trees(); | |
1380 | audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE); | |
1381 | audit_log_format(ab, " op=trim res=1"); | |
1382 | audit_log_end(ab); | |
1383 | break; | |
1384 | case AUDIT_MAKE_EQUIV: { | |
1385 | void *bufp = data; | |
1386 | u32 sizes[2]; | |
1387 | size_t msglen = nlmsg_len(nlh); | |
1388 | char *old, *new; | |
1389 | ||
1390 | err = -EINVAL; | |
1391 | if (msglen < 2 * sizeof(u32)) | |
1392 | break; | |
1393 | memcpy(sizes, bufp, 2 * sizeof(u32)); | |
1394 | bufp += 2 * sizeof(u32); | |
1395 | msglen -= 2 * sizeof(u32); | |
1396 | old = audit_unpack_string(&bufp, &msglen, sizes[0]); | |
1397 | if (IS_ERR(old)) { | |
1398 | err = PTR_ERR(old); | |
1399 | break; | |
1400 | } | |
1401 | new = audit_unpack_string(&bufp, &msglen, sizes[1]); | |
1402 | if (IS_ERR(new)) { | |
1403 | err = PTR_ERR(new); | |
1404 | kfree(old); | |
1405 | break; | |
1406 | } | |
1407 | /* OK, here comes... */ | |
1408 | err = audit_tag_tree(old, new); | |
1409 | ||
1410 | audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE); | |
1411 | ||
1412 | audit_log_format(ab, " op=make_equiv old="); | |
1413 | audit_log_untrustedstring(ab, old); | |
1414 | audit_log_format(ab, " new="); | |
1415 | audit_log_untrustedstring(ab, new); | |
1416 | audit_log_format(ab, " res=%d", !err); | |
1417 | audit_log_end(ab); | |
1418 | kfree(old); | |
1419 | kfree(new); | |
1420 | break; | |
1421 | } | |
1422 | case AUDIT_SIGNAL_INFO: | |
1423 | len = 0; | |
1424 | if (audit_sig_sid) { | |
1425 | err = security_secid_to_secctx(audit_sig_sid, &ctx, &len); | |
1426 | if (err) | |
1427 | return err; | |
1428 | } | |
1429 | sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL); | |
1430 | if (!sig_data) { | |
1431 | if (audit_sig_sid) | |
1432 | security_release_secctx(ctx, len); | |
1433 | return -ENOMEM; | |
1434 | } | |
1435 | sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid); | |
1436 | sig_data->pid = audit_sig_pid; | |
1437 | if (audit_sig_sid) { | |
1438 | memcpy(sig_data->ctx, ctx, len); | |
1439 | security_release_secctx(ctx, len); | |
1440 | } | |
1441 | audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0, | |
1442 | sig_data, sizeof(*sig_data) + len); | |
1443 | kfree(sig_data); | |
1444 | break; | |
1445 | case AUDIT_TTY_GET: { | |
1446 | struct audit_tty_status s; | |
1447 | unsigned int t; | |
1448 | ||
1449 | t = READ_ONCE(current->signal->audit_tty); | |
1450 | s.enabled = t & AUDIT_TTY_ENABLE; | |
1451 | s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD); | |
1452 | ||
1453 | audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s)); | |
1454 | break; | |
1455 | } | |
1456 | case AUDIT_TTY_SET: { | |
1457 | struct audit_tty_status s, old; | |
1458 | struct audit_buffer *ab; | |
1459 | unsigned int t; | |
1460 | ||
1461 | memset(&s, 0, sizeof(s)); | |
1462 | /* guard against past and future API changes */ | |
1463 | memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh))); | |
1464 | /* check if new data is valid */ | |
1465 | if ((s.enabled != 0 && s.enabled != 1) || | |
1466 | (s.log_passwd != 0 && s.log_passwd != 1)) | |
1467 | err = -EINVAL; | |
1468 | ||
1469 | if (err) | |
1470 | t = READ_ONCE(current->signal->audit_tty); | |
1471 | else { | |
1472 | t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD); | |
1473 | t = xchg(¤t->signal->audit_tty, t); | |
1474 | } | |
1475 | old.enabled = t & AUDIT_TTY_ENABLE; | |
1476 | old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD); | |
1477 | ||
1478 | audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE); | |
1479 | audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d" | |
1480 | " old-log_passwd=%d new-log_passwd=%d res=%d", | |
1481 | old.enabled, s.enabled, old.log_passwd, | |
1482 | s.log_passwd, !err); | |
1483 | audit_log_end(ab); | |
1484 | break; | |
1485 | } | |
1486 | default: | |
1487 | err = -EINVAL; | |
1488 | break; | |
1489 | } | |
1490 | ||
1491 | return err < 0 ? err : 0; | |
1492 | } | |
1493 | ||
1494 | /** | |
1495 | * audit_receive - receive messages from a netlink control socket | |
1496 | * @skb: the message buffer | |
1497 | * | |
1498 | * Parse the provided skb and deal with any messages that may be present, | |
1499 | * malformed skbs are discarded. | |
1500 | */ | |
1501 | static void audit_receive(struct sk_buff *skb) | |
1502 | { | |
1503 | struct nlmsghdr *nlh; | |
1504 | /* | |
1505 | * len MUST be signed for nlmsg_next to be able to dec it below 0 | |
1506 | * if the nlmsg_len was not aligned | |
1507 | */ | |
1508 | int len; | |
1509 | int err; | |
1510 | ||
1511 | nlh = nlmsg_hdr(skb); | |
1512 | len = skb->len; | |
1513 | ||
1514 | audit_ctl_lock(); | |
1515 | while (nlmsg_ok(nlh, len)) { | |
1516 | err = audit_receive_msg(skb, nlh); | |
1517 | /* if err or if this message says it wants a response */ | |
1518 | if (err || (nlh->nlmsg_flags & NLM_F_ACK)) | |
1519 | netlink_ack(skb, nlh, err, NULL); | |
1520 | ||
1521 | nlh = nlmsg_next(nlh, &len); | |
1522 | } | |
1523 | audit_ctl_unlock(); | |
1524 | } | |
1525 | ||
1526 | /* Run custom bind function on netlink socket group connect or bind requests. */ | |
1527 | static int audit_bind(struct net *net, int group) | |
1528 | { | |
1529 | if (!capable(CAP_AUDIT_READ)) | |
1530 | return -EPERM; | |
1531 | ||
1532 | return 0; | |
1533 | } | |
1534 | ||
1535 | static int __net_init audit_net_init(struct net *net) | |
1536 | { | |
1537 | struct netlink_kernel_cfg cfg = { | |
1538 | .input = audit_receive, | |
1539 | .bind = audit_bind, | |
1540 | .flags = NL_CFG_F_NONROOT_RECV, | |
1541 | .groups = AUDIT_NLGRP_MAX, | |
1542 | }; | |
1543 | ||
1544 | struct audit_net *aunet = net_generic(net, audit_net_id); | |
1545 | ||
1546 | aunet->sk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg); | |
1547 | if (aunet->sk == NULL) { | |
1548 | audit_panic("cannot initialize netlink socket in namespace"); | |
1549 | return -ENOMEM; | |
1550 | } | |
1551 | aunet->sk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT; | |
1552 | ||
1553 | return 0; | |
1554 | } | |
1555 | ||
1556 | static void __net_exit audit_net_exit(struct net *net) | |
1557 | { | |
1558 | struct audit_net *aunet = net_generic(net, audit_net_id); | |
1559 | ||
1560 | /* NOTE: you would think that we would want to check the auditd | |
1561 | * connection and potentially reset it here if it lives in this | |
1562 | * namespace, but since the auditd connection tracking struct holds a | |
1563 | * reference to this namespace (see auditd_set()) we are only ever | |
1564 | * going to get here after that connection has been released */ | |
1565 | ||
1566 | netlink_kernel_release(aunet->sk); | |
1567 | } | |
1568 | ||
1569 | static struct pernet_operations audit_net_ops __net_initdata = { | |
1570 | .init = audit_net_init, | |
1571 | .exit = audit_net_exit, | |
1572 | .id = &audit_net_id, | |
1573 | .size = sizeof(struct audit_net), | |
1574 | }; | |
1575 | ||
1576 | /* Initialize audit support at boot time. */ | |
1577 | static int __init audit_init(void) | |
1578 | { | |
1579 | int i; | |
1580 | ||
1581 | if (audit_initialized == AUDIT_DISABLED) | |
1582 | return 0; | |
1583 | ||
1584 | audit_buffer_cache = kmem_cache_create("audit_buffer", | |
1585 | sizeof(struct audit_buffer), | |
1586 | 0, SLAB_PANIC, NULL); | |
1587 | ||
1588 | skb_queue_head_init(&audit_queue); | |
1589 | skb_queue_head_init(&audit_retry_queue); | |
1590 | skb_queue_head_init(&audit_hold_queue); | |
1591 | ||
1592 | for (i = 0; i < AUDIT_INODE_BUCKETS; i++) | |
1593 | INIT_LIST_HEAD(&audit_inode_hash[i]); | |
1594 | ||
1595 | mutex_init(&audit_cmd_mutex.lock); | |
1596 | audit_cmd_mutex.owner = NULL; | |
1597 | ||
1598 | pr_info("initializing netlink subsys (%s)\n", | |
1599 | audit_default ? "enabled" : "disabled"); | |
1600 | register_pernet_subsys(&audit_net_ops); | |
1601 | ||
1602 | audit_initialized = AUDIT_INITIALIZED; | |
1603 | ||
1604 | kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd"); | |
1605 | if (IS_ERR(kauditd_task)) { | |
1606 | int err = PTR_ERR(kauditd_task); | |
1607 | panic("audit: failed to start the kauditd thread (%d)\n", err); | |
1608 | } | |
1609 | ||
1610 | audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, | |
1611 | "state=initialized audit_enabled=%u res=1", | |
1612 | audit_enabled); | |
1613 | ||
1614 | return 0; | |
1615 | } | |
1616 | postcore_initcall(audit_init); | |
1617 | ||
1618 | /* | |
1619 | * Process kernel command-line parameter at boot time. | |
1620 | * audit={0|off} or audit={1|on}. | |
1621 | */ | |
1622 | static int __init audit_enable(char *str) | |
1623 | { | |
1624 | if (!strcasecmp(str, "off") || !strcmp(str, "0")) | |
1625 | audit_default = AUDIT_OFF; | |
1626 | else if (!strcasecmp(str, "on") || !strcmp(str, "1")) | |
1627 | audit_default = AUDIT_ON; | |
1628 | else { | |
1629 | pr_err("audit: invalid 'audit' parameter value (%s)\n", str); | |
1630 | audit_default = AUDIT_ON; | |
1631 | } | |
1632 | ||
1633 | if (audit_default == AUDIT_OFF) | |
1634 | audit_initialized = AUDIT_DISABLED; | |
1635 | if (audit_set_enabled(audit_default)) | |
1636 | pr_err("audit: error setting audit state (%d)\n", | |
1637 | audit_default); | |
1638 | ||
1639 | pr_info("%s\n", audit_default ? | |
1640 | "enabled (after initialization)" : "disabled (until reboot)"); | |
1641 | ||
1642 | return 1; | |
1643 | } | |
1644 | __setup("audit=", audit_enable); | |
1645 | ||
1646 | /* Process kernel command-line parameter at boot time. | |
1647 | * audit_backlog_limit=<n> */ | |
1648 | static int __init audit_backlog_limit_set(char *str) | |
1649 | { | |
1650 | u32 audit_backlog_limit_arg; | |
1651 | ||
1652 | pr_info("audit_backlog_limit: "); | |
1653 | if (kstrtouint(str, 0, &audit_backlog_limit_arg)) { | |
1654 | pr_cont("using default of %u, unable to parse %s\n", | |
1655 | audit_backlog_limit, str); | |
1656 | return 1; | |
1657 | } | |
1658 | ||
1659 | audit_backlog_limit = audit_backlog_limit_arg; | |
1660 | pr_cont("%d\n", audit_backlog_limit); | |
1661 | ||
1662 | return 1; | |
1663 | } | |
1664 | __setup("audit_backlog_limit=", audit_backlog_limit_set); | |
1665 | ||
1666 | static void audit_buffer_free(struct audit_buffer *ab) | |
1667 | { | |
1668 | if (!ab) | |
1669 | return; | |
1670 | ||
1671 | kfree_skb(ab->skb); | |
1672 | kmem_cache_free(audit_buffer_cache, ab); | |
1673 | } | |
1674 | ||
1675 | static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx, | |
1676 | gfp_t gfp_mask, int type) | |
1677 | { | |
1678 | struct audit_buffer *ab; | |
1679 | ||
1680 | ab = kmem_cache_alloc(audit_buffer_cache, gfp_mask); | |
1681 | if (!ab) | |
1682 | return NULL; | |
1683 | ||
1684 | ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask); | |
1685 | if (!ab->skb) | |
1686 | goto err; | |
1687 | if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0)) | |
1688 | goto err; | |
1689 | ||
1690 | ab->ctx = ctx; | |
1691 | ab->gfp_mask = gfp_mask; | |
1692 | ||
1693 | return ab; | |
1694 | ||
1695 | err: | |
1696 | audit_buffer_free(ab); | |
1697 | return NULL; | |
1698 | } | |
1699 | ||
1700 | /** | |
1701 | * audit_serial - compute a serial number for the audit record | |
1702 | * | |
1703 | * Compute a serial number for the audit record. Audit records are | |
1704 | * written to user-space as soon as they are generated, so a complete | |
1705 | * audit record may be written in several pieces. The timestamp of the | |
1706 | * record and this serial number are used by the user-space tools to | |
1707 | * determine which pieces belong to the same audit record. The | |
1708 | * (timestamp,serial) tuple is unique for each syscall and is live from | |
1709 | * syscall entry to syscall exit. | |
1710 | * | |
1711 | * NOTE: Another possibility is to store the formatted records off the | |
1712 | * audit context (for those records that have a context), and emit them | |
1713 | * all at syscall exit. However, this could delay the reporting of | |
1714 | * significant errors until syscall exit (or never, if the system | |
1715 | * halts). | |
1716 | */ | |
1717 | unsigned int audit_serial(void) | |
1718 | { | |
1719 | static atomic_t serial = ATOMIC_INIT(0); | |
1720 | ||
1721 | return atomic_add_return(1, &serial); | |
1722 | } | |
1723 | ||
1724 | static inline void audit_get_stamp(struct audit_context *ctx, | |
1725 | struct timespec64 *t, unsigned int *serial) | |
1726 | { | |
1727 | if (!ctx || !auditsc_get_stamp(ctx, t, serial)) { | |
1728 | *t = current_kernel_time64(); | |
1729 | *serial = audit_serial(); | |
1730 | } | |
1731 | } | |
1732 | ||
1733 | /** | |
1734 | * audit_log_start - obtain an audit buffer | |
1735 | * @ctx: audit_context (may be NULL) | |
1736 | * @gfp_mask: type of allocation | |
1737 | * @type: audit message type | |
1738 | * | |
1739 | * Returns audit_buffer pointer on success or NULL on error. | |
1740 | * | |
1741 | * Obtain an audit buffer. This routine does locking to obtain the | |
1742 | * audit buffer, but then no locking is required for calls to | |
1743 | * audit_log_*format. If the task (ctx) is a task that is currently in a | |
1744 | * syscall, then the syscall is marked as auditable and an audit record | |
1745 | * will be written at syscall exit. If there is no associated task, then | |
1746 | * task context (ctx) should be NULL. | |
1747 | */ | |
1748 | struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, | |
1749 | int type) | |
1750 | { | |
1751 | struct audit_buffer *ab; | |
1752 | struct timespec64 t; | |
1753 | unsigned int uninitialized_var(serial); | |
1754 | ||
1755 | if (audit_initialized != AUDIT_INITIALIZED) | |
1756 | return NULL; | |
1757 | ||
1758 | if (unlikely(!audit_filter(type, AUDIT_FILTER_TYPE))) | |
1759 | return NULL; | |
1760 | ||
1761 | /* NOTE: don't ever fail/sleep on these two conditions: | |
1762 | * 1. auditd generated record - since we need auditd to drain the | |
1763 | * queue; also, when we are checking for auditd, compare PIDs using | |
1764 | * task_tgid_vnr() since auditd_pid is set in audit_receive_msg() | |
1765 | * using a PID anchored in the caller's namespace | |
1766 | * 2. generator holding the audit_cmd_mutex - we don't want to block | |
1767 | * while holding the mutex */ | |
1768 | if (!(auditd_test_task(current) || audit_ctl_owner_current())) { | |
1769 | long stime = audit_backlog_wait_time; | |
1770 | ||
1771 | while (audit_backlog_limit && | |
1772 | (skb_queue_len(&audit_queue) > audit_backlog_limit)) { | |
1773 | /* wake kauditd to try and flush the queue */ | |
1774 | wake_up_interruptible(&kauditd_wait); | |
1775 | ||
1776 | /* sleep if we are allowed and we haven't exhausted our | |
1777 | * backlog wait limit */ | |
1778 | if (gfpflags_allow_blocking(gfp_mask) && (stime > 0)) { | |
1779 | DECLARE_WAITQUEUE(wait, current); | |
1780 | ||
1781 | add_wait_queue_exclusive(&audit_backlog_wait, | |
1782 | &wait); | |
1783 | set_current_state(TASK_UNINTERRUPTIBLE); | |
1784 | stime = schedule_timeout(stime); | |
1785 | remove_wait_queue(&audit_backlog_wait, &wait); | |
1786 | } else { | |
1787 | if (audit_rate_check() && printk_ratelimit()) | |
1788 | pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n", | |
1789 | skb_queue_len(&audit_queue), | |
1790 | audit_backlog_limit); | |
1791 | audit_log_lost("backlog limit exceeded"); | |
1792 | return NULL; | |
1793 | } | |
1794 | } | |
1795 | } | |
1796 | ||
1797 | ab = audit_buffer_alloc(ctx, gfp_mask, type); | |
1798 | if (!ab) { | |
1799 | audit_log_lost("out of memory in audit_log_start"); | |
1800 | return NULL; | |
1801 | } | |
1802 | ||
1803 | audit_get_stamp(ab->ctx, &t, &serial); | |
1804 | audit_log_format(ab, "audit(%llu.%03lu:%u): ", | |
1805 | (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial); | |
1806 | ||
1807 | return ab; | |
1808 | } | |
1809 | ||
1810 | /** | |
1811 | * audit_expand - expand skb in the audit buffer | |
1812 | * @ab: audit_buffer | |
1813 | * @extra: space to add at tail of the skb | |
1814 | * | |
1815 | * Returns 0 (no space) on failed expansion, or available space if | |
1816 | * successful. | |
1817 | */ | |
1818 | static inline int audit_expand(struct audit_buffer *ab, int extra) | |
1819 | { | |
1820 | struct sk_buff *skb = ab->skb; | |
1821 | int oldtail = skb_tailroom(skb); | |
1822 | int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask); | |
1823 | int newtail = skb_tailroom(skb); | |
1824 | ||
1825 | if (ret < 0) { | |
1826 | audit_log_lost("out of memory in audit_expand"); | |
1827 | return 0; | |
1828 | } | |
1829 | ||
1830 | skb->truesize += newtail - oldtail; | |
1831 | return newtail; | |
1832 | } | |
1833 | ||
1834 | /* | |
1835 | * Format an audit message into the audit buffer. If there isn't enough | |
1836 | * room in the audit buffer, more room will be allocated and vsnprint | |
1837 | * will be called a second time. Currently, we assume that a printk | |
1838 | * can't format message larger than 1024 bytes, so we don't either. | |
1839 | */ | |
1840 | static void audit_log_vformat(struct audit_buffer *ab, const char *fmt, | |
1841 | va_list args) | |
1842 | { | |
1843 | int len, avail; | |
1844 | struct sk_buff *skb; | |
1845 | va_list args2; | |
1846 | ||
1847 | if (!ab) | |
1848 | return; | |
1849 | ||
1850 | BUG_ON(!ab->skb); | |
1851 | skb = ab->skb; | |
1852 | avail = skb_tailroom(skb); | |
1853 | if (avail == 0) { | |
1854 | avail = audit_expand(ab, AUDIT_BUFSIZ); | |
1855 | if (!avail) | |
1856 | goto out; | |
1857 | } | |
1858 | va_copy(args2, args); | |
1859 | len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args); | |
1860 | if (len >= avail) { | |
1861 | /* The printk buffer is 1024 bytes long, so if we get | |
1862 | * here and AUDIT_BUFSIZ is at least 1024, then we can | |
1863 | * log everything that printk could have logged. */ | |
1864 | avail = audit_expand(ab, | |
1865 | max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail)); | |
1866 | if (!avail) | |
1867 | goto out_va_end; | |
1868 | len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2); | |
1869 | } | |
1870 | if (len > 0) | |
1871 | skb_put(skb, len); | |
1872 | out_va_end: | |
1873 | va_end(args2); | |
1874 | out: | |
1875 | return; | |
1876 | } | |
1877 | ||
1878 | /** | |
1879 | * audit_log_format - format a message into the audit buffer. | |
1880 | * @ab: audit_buffer | |
1881 | * @fmt: format string | |
1882 | * @...: optional parameters matching @fmt string | |
1883 | * | |
1884 | * All the work is done in audit_log_vformat. | |
1885 | */ | |
1886 | void audit_log_format(struct audit_buffer *ab, const char *fmt, ...) | |
1887 | { | |
1888 | va_list args; | |
1889 | ||
1890 | if (!ab) | |
1891 | return; | |
1892 | va_start(args, fmt); | |
1893 | audit_log_vformat(ab, fmt, args); | |
1894 | va_end(args); | |
1895 | } | |
1896 | ||
1897 | /** | |
1898 | * audit_log_n_hex - convert a buffer to hex and append it to the audit skb | |
1899 | * @ab: the audit_buffer | |
1900 | * @buf: buffer to convert to hex | |
1901 | * @len: length of @buf to be converted | |
1902 | * | |
1903 | * No return value; failure to expand is silently ignored. | |
1904 | * | |
1905 | * This function will take the passed buf and convert it into a string of | |
1906 | * ascii hex digits. The new string is placed onto the skb. | |
1907 | */ | |
1908 | void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf, | |
1909 | size_t len) | |
1910 | { | |
1911 | int i, avail, new_len; | |
1912 | unsigned char *ptr; | |
1913 | struct sk_buff *skb; | |
1914 | ||
1915 | if (!ab) | |
1916 | return; | |
1917 | ||
1918 | BUG_ON(!ab->skb); | |
1919 | skb = ab->skb; | |
1920 | avail = skb_tailroom(skb); | |
1921 | new_len = len<<1; | |
1922 | if (new_len >= avail) { | |
1923 | /* Round the buffer request up to the next multiple */ | |
1924 | new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1); | |
1925 | avail = audit_expand(ab, new_len); | |
1926 | if (!avail) | |
1927 | return; | |
1928 | } | |
1929 | ||
1930 | ptr = skb_tail_pointer(skb); | |
1931 | for (i = 0; i < len; i++) | |
1932 | ptr = hex_byte_pack_upper(ptr, buf[i]); | |
1933 | *ptr = 0; | |
1934 | skb_put(skb, len << 1); /* new string is twice the old string */ | |
1935 | } | |
1936 | ||
1937 | /* | |
1938 | * Format a string of no more than slen characters into the audit buffer, | |
1939 | * enclosed in quote marks. | |
1940 | */ | |
1941 | void audit_log_n_string(struct audit_buffer *ab, const char *string, | |
1942 | size_t slen) | |
1943 | { | |
1944 | int avail, new_len; | |
1945 | unsigned char *ptr; | |
1946 | struct sk_buff *skb; | |
1947 | ||
1948 | if (!ab) | |
1949 | return; | |
1950 | ||
1951 | BUG_ON(!ab->skb); | |
1952 | skb = ab->skb; | |
1953 | avail = skb_tailroom(skb); | |
1954 | new_len = slen + 3; /* enclosing quotes + null terminator */ | |
1955 | if (new_len > avail) { | |
1956 | avail = audit_expand(ab, new_len); | |
1957 | if (!avail) | |
1958 | return; | |
1959 | } | |
1960 | ptr = skb_tail_pointer(skb); | |
1961 | *ptr++ = '"'; | |
1962 | memcpy(ptr, string, slen); | |
1963 | ptr += slen; | |
1964 | *ptr++ = '"'; | |
1965 | *ptr = 0; | |
1966 | skb_put(skb, slen + 2); /* don't include null terminator */ | |
1967 | } | |
1968 | ||
1969 | /** | |
1970 | * audit_string_contains_control - does a string need to be logged in hex | |
1971 | * @string: string to be checked | |
1972 | * @len: max length of the string to check | |
1973 | */ | |
1974 | bool audit_string_contains_control(const char *string, size_t len) | |
1975 | { | |
1976 | const unsigned char *p; | |
1977 | for (p = string; p < (const unsigned char *)string + len; p++) { | |
1978 | if (*p == '"' || *p < 0x21 || *p > 0x7e) | |
1979 | return true; | |
1980 | } | |
1981 | return false; | |
1982 | } | |
1983 | ||
1984 | /** | |
1985 | * audit_log_n_untrustedstring - log a string that may contain random characters | |
1986 | * @ab: audit_buffer | |
1987 | * @len: length of string (not including trailing null) | |
1988 | * @string: string to be logged | |
1989 | * | |
1990 | * This code will escape a string that is passed to it if the string | |
1991 | * contains a control character, unprintable character, double quote mark, | |
1992 | * or a space. Unescaped strings will start and end with a double quote mark. | |
1993 | * Strings that are escaped are printed in hex (2 digits per char). | |
1994 | * | |
1995 | * The caller specifies the number of characters in the string to log, which may | |
1996 | * or may not be the entire string. | |
1997 | */ | |
1998 | void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string, | |
1999 | size_t len) | |
2000 | { | |
2001 | if (audit_string_contains_control(string, len)) | |
2002 | audit_log_n_hex(ab, string, len); | |
2003 | else | |
2004 | audit_log_n_string(ab, string, len); | |
2005 | } | |
2006 | ||
2007 | /** | |
2008 | * audit_log_untrustedstring - log a string that may contain random characters | |
2009 | * @ab: audit_buffer | |
2010 | * @string: string to be logged | |
2011 | * | |
2012 | * Same as audit_log_n_untrustedstring(), except that strlen is used to | |
2013 | * determine string length. | |
2014 | */ | |
2015 | void audit_log_untrustedstring(struct audit_buffer *ab, const char *string) | |
2016 | { | |
2017 | audit_log_n_untrustedstring(ab, string, strlen(string)); | |
2018 | } | |
2019 | ||
2020 | /* This is a helper-function to print the escaped d_path */ | |
2021 | void audit_log_d_path(struct audit_buffer *ab, const char *prefix, | |
2022 | const struct path *path) | |
2023 | { | |
2024 | char *p, *pathname; | |
2025 | ||
2026 | if (prefix) | |
2027 | audit_log_format(ab, "%s", prefix); | |
2028 | ||
2029 | /* We will allow 11 spaces for ' (deleted)' to be appended */ | |
2030 | pathname = kmalloc(PATH_MAX+11, ab->gfp_mask); | |
2031 | if (!pathname) { | |
2032 | audit_log_string(ab, "<no_memory>"); | |
2033 | return; | |
2034 | } | |
2035 | p = d_path(path, pathname, PATH_MAX+11); | |
2036 | if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */ | |
2037 | /* FIXME: can we save some information here? */ | |
2038 | audit_log_string(ab, "<too_long>"); | |
2039 | } else | |
2040 | audit_log_untrustedstring(ab, p); | |
2041 | kfree(pathname); | |
2042 | } | |
2043 | ||
2044 | void audit_log_session_info(struct audit_buffer *ab) | |
2045 | { | |
2046 | unsigned int sessionid = audit_get_sessionid(current); | |
2047 | uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current)); | |
2048 | ||
2049 | audit_log_format(ab, " auid=%u ses=%u", auid, sessionid); | |
2050 | } | |
2051 | ||
2052 | void audit_log_key(struct audit_buffer *ab, char *key) | |
2053 | { | |
2054 | audit_log_format(ab, " key="); | |
2055 | if (key) | |
2056 | audit_log_untrustedstring(ab, key); | |
2057 | else | |
2058 | audit_log_format(ab, "(null)"); | |
2059 | } | |
2060 | ||
2061 | void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap) | |
2062 | { | |
2063 | int i; | |
2064 | ||
2065 | audit_log_format(ab, " %s=", prefix); | |
2066 | CAP_FOR_EACH_U32(i) { | |
2067 | audit_log_format(ab, "%08x", | |
2068 | cap->cap[CAP_LAST_U32 - i]); | |
2069 | } | |
2070 | } | |
2071 | ||
2072 | static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name) | |
2073 | { | |
2074 | audit_log_cap(ab, "cap_fp", &name->fcap.permitted); | |
2075 | audit_log_cap(ab, "cap_fi", &name->fcap.inheritable); | |
2076 | audit_log_format(ab, " cap_fe=%d cap_fver=%x", | |
2077 | name->fcap.fE, name->fcap_ver); | |
2078 | } | |
2079 | ||
2080 | static inline int audit_copy_fcaps(struct audit_names *name, | |
2081 | const struct dentry *dentry) | |
2082 | { | |
2083 | struct cpu_vfs_cap_data caps; | |
2084 | int rc; | |
2085 | ||
2086 | if (!dentry) | |
2087 | return 0; | |
2088 | ||
2089 | rc = get_vfs_caps_from_disk(dentry, &caps); | |
2090 | if (rc) | |
2091 | return rc; | |
2092 | ||
2093 | name->fcap.permitted = caps.permitted; | |
2094 | name->fcap.inheritable = caps.inheritable; | |
2095 | name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE); | |
2096 | name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >> | |
2097 | VFS_CAP_REVISION_SHIFT; | |
2098 | ||
2099 | return 0; | |
2100 | } | |
2101 | ||
2102 | /* Copy inode data into an audit_names. */ | |
2103 | void audit_copy_inode(struct audit_names *name, const struct dentry *dentry, | |
2104 | struct inode *inode) | |
2105 | { | |
2106 | name->ino = inode->i_ino; | |
2107 | name->dev = inode->i_sb->s_dev; | |
2108 | name->mode = inode->i_mode; | |
2109 | name->uid = inode->i_uid; | |
2110 | name->gid = inode->i_gid; | |
2111 | name->rdev = inode->i_rdev; | |
2112 | security_inode_getsecid(inode, &name->osid); | |
2113 | audit_copy_fcaps(name, dentry); | |
2114 | } | |
2115 | ||
2116 | /** | |
2117 | * audit_log_name - produce AUDIT_PATH record from struct audit_names | |
2118 | * @context: audit_context for the task | |
2119 | * @n: audit_names structure with reportable details | |
2120 | * @path: optional path to report instead of audit_names->name | |
2121 | * @record_num: record number to report when handling a list of names | |
2122 | * @call_panic: optional pointer to int that will be updated if secid fails | |
2123 | */ | |
2124 | void audit_log_name(struct audit_context *context, struct audit_names *n, | |
2125 | const struct path *path, int record_num, int *call_panic) | |
2126 | { | |
2127 | struct audit_buffer *ab; | |
2128 | ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH); | |
2129 | if (!ab) | |
2130 | return; | |
2131 | ||
2132 | audit_log_format(ab, "item=%d", record_num); | |
2133 | ||
2134 | if (path) | |
2135 | audit_log_d_path(ab, " name=", path); | |
2136 | else if (n->name) { | |
2137 | switch (n->name_len) { | |
2138 | case AUDIT_NAME_FULL: | |
2139 | /* log the full path */ | |
2140 | audit_log_format(ab, " name="); | |
2141 | audit_log_untrustedstring(ab, n->name->name); | |
2142 | break; | |
2143 | case 0: | |
2144 | /* name was specified as a relative path and the | |
2145 | * directory component is the cwd */ | |
2146 | audit_log_d_path(ab, " name=", &context->pwd); | |
2147 | break; | |
2148 | default: | |
2149 | /* log the name's directory component */ | |
2150 | audit_log_format(ab, " name="); | |
2151 | audit_log_n_untrustedstring(ab, n->name->name, | |
2152 | n->name_len); | |
2153 | } | |
2154 | } else | |
2155 | audit_log_format(ab, " name=(null)"); | |
2156 | ||
2157 | if (n->ino != AUDIT_INO_UNSET) | |
2158 | audit_log_format(ab, " inode=%lu" | |
2159 | " dev=%02x:%02x mode=%#ho" | |
2160 | " ouid=%u ogid=%u rdev=%02x:%02x", | |
2161 | n->ino, | |
2162 | MAJOR(n->dev), | |
2163 | MINOR(n->dev), | |
2164 | n->mode, | |
2165 | from_kuid(&init_user_ns, n->uid), | |
2166 | from_kgid(&init_user_ns, n->gid), | |
2167 | MAJOR(n->rdev), | |
2168 | MINOR(n->rdev)); | |
2169 | if (n->osid != 0) { | |
2170 | char *ctx = NULL; | |
2171 | u32 len; | |
2172 | if (security_secid_to_secctx( | |
2173 | n->osid, &ctx, &len)) { | |
2174 | audit_log_format(ab, " osid=%u", n->osid); | |
2175 | if (call_panic) | |
2176 | *call_panic = 2; | |
2177 | } else { | |
2178 | audit_log_format(ab, " obj=%s", ctx); | |
2179 | security_release_secctx(ctx, len); | |
2180 | } | |
2181 | } | |
2182 | ||
2183 | /* log the audit_names record type */ | |
2184 | audit_log_format(ab, " nametype="); | |
2185 | switch(n->type) { | |
2186 | case AUDIT_TYPE_NORMAL: | |
2187 | audit_log_format(ab, "NORMAL"); | |
2188 | break; | |
2189 | case AUDIT_TYPE_PARENT: | |
2190 | audit_log_format(ab, "PARENT"); | |
2191 | break; | |
2192 | case AUDIT_TYPE_CHILD_DELETE: | |
2193 | audit_log_format(ab, "DELETE"); | |
2194 | break; | |
2195 | case AUDIT_TYPE_CHILD_CREATE: | |
2196 | audit_log_format(ab, "CREATE"); | |
2197 | break; | |
2198 | default: | |
2199 | audit_log_format(ab, "UNKNOWN"); | |
2200 | break; | |
2201 | } | |
2202 | ||
2203 | audit_log_fcaps(ab, n); | |
2204 | audit_log_end(ab); | |
2205 | } | |
2206 | ||
2207 | int audit_log_task_context(struct audit_buffer *ab) | |
2208 | { | |
2209 | char *ctx = NULL; | |
2210 | unsigned len; | |
2211 | int error; | |
2212 | u32 sid; | |
2213 | ||
2214 | security_task_getsecid(current, &sid); | |
2215 | if (!sid) | |
2216 | return 0; | |
2217 | ||
2218 | error = security_secid_to_secctx(sid, &ctx, &len); | |
2219 | if (error) { | |
2220 | if (error != -EINVAL) | |
2221 | goto error_path; | |
2222 | return 0; | |
2223 | } | |
2224 | ||
2225 | audit_log_format(ab, " subj=%s", ctx); | |
2226 | security_release_secctx(ctx, len); | |
2227 | return 0; | |
2228 | ||
2229 | error_path: | |
2230 | audit_panic("error in audit_log_task_context"); | |
2231 | return error; | |
2232 | } | |
2233 | EXPORT_SYMBOL(audit_log_task_context); | |
2234 | ||
2235 | void audit_log_d_path_exe(struct audit_buffer *ab, | |
2236 | struct mm_struct *mm) | |
2237 | { | |
2238 | struct file *exe_file; | |
2239 | ||
2240 | if (!mm) | |
2241 | goto out_null; | |
2242 | ||
2243 | exe_file = get_mm_exe_file(mm); | |
2244 | if (!exe_file) | |
2245 | goto out_null; | |
2246 | ||
2247 | audit_log_d_path(ab, " exe=", &exe_file->f_path); | |
2248 | fput(exe_file); | |
2249 | return; | |
2250 | out_null: | |
2251 | audit_log_format(ab, " exe=(null)"); | |
2252 | } | |
2253 | ||
2254 | struct tty_struct *audit_get_tty(struct task_struct *tsk) | |
2255 | { | |
2256 | struct tty_struct *tty = NULL; | |
2257 | unsigned long flags; | |
2258 | ||
2259 | spin_lock_irqsave(&tsk->sighand->siglock, flags); | |
2260 | if (tsk->signal) | |
2261 | tty = tty_kref_get(tsk->signal->tty); | |
2262 | spin_unlock_irqrestore(&tsk->sighand->siglock, flags); | |
2263 | return tty; | |
2264 | } | |
2265 | ||
2266 | void audit_put_tty(struct tty_struct *tty) | |
2267 | { | |
2268 | tty_kref_put(tty); | |
2269 | } | |
2270 | ||
2271 | void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk) | |
2272 | { | |
2273 | const struct cred *cred; | |
2274 | char comm[sizeof(tsk->comm)]; | |
2275 | struct tty_struct *tty; | |
2276 | ||
2277 | if (!ab) | |
2278 | return; | |
2279 | ||
2280 | /* tsk == current */ | |
2281 | cred = current_cred(); | |
2282 | tty = audit_get_tty(tsk); | |
2283 | audit_log_format(ab, | |
2284 | " ppid=%d pid=%d auid=%u uid=%u gid=%u" | |
2285 | " euid=%u suid=%u fsuid=%u" | |
2286 | " egid=%u sgid=%u fsgid=%u tty=%s ses=%u", | |
2287 | task_ppid_nr(tsk), | |
2288 | task_tgid_nr(tsk), | |
2289 | from_kuid(&init_user_ns, audit_get_loginuid(tsk)), | |
2290 | from_kuid(&init_user_ns, cred->uid), | |
2291 | from_kgid(&init_user_ns, cred->gid), | |
2292 | from_kuid(&init_user_ns, cred->euid), | |
2293 | from_kuid(&init_user_ns, cred->suid), | |
2294 | from_kuid(&init_user_ns, cred->fsuid), | |
2295 | from_kgid(&init_user_ns, cred->egid), | |
2296 | from_kgid(&init_user_ns, cred->sgid), | |
2297 | from_kgid(&init_user_ns, cred->fsgid), | |
2298 | tty ? tty_name(tty) : "(none)", | |
2299 | audit_get_sessionid(tsk)); | |
2300 | audit_put_tty(tty); | |
2301 | audit_log_format(ab, " comm="); | |
2302 | audit_log_untrustedstring(ab, get_task_comm(comm, tsk)); | |
2303 | audit_log_d_path_exe(ab, tsk->mm); | |
2304 | audit_log_task_context(ab); | |
2305 | } | |
2306 | EXPORT_SYMBOL(audit_log_task_info); | |
2307 | ||
2308 | /** | |
2309 | * audit_log_link_denied - report a link restriction denial | |
2310 | * @operation: specific link operation | |
2311 | * @link: the path that triggered the restriction | |
2312 | */ | |
2313 | void audit_log_link_denied(const char *operation, const struct path *link) | |
2314 | { | |
2315 | struct audit_buffer *ab; | |
2316 | struct audit_names *name; | |
2317 | ||
2318 | name = kzalloc(sizeof(*name), GFP_NOFS); | |
2319 | if (!name) | |
2320 | return; | |
2321 | ||
2322 | /* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */ | |
2323 | ab = audit_log_start(current->audit_context, GFP_KERNEL, | |
2324 | AUDIT_ANOM_LINK); | |
2325 | if (!ab) | |
2326 | goto out; | |
2327 | audit_log_format(ab, "op=%s", operation); | |
2328 | audit_log_task_info(ab, current); | |
2329 | audit_log_format(ab, " res=0"); | |
2330 | audit_log_end(ab); | |
2331 | ||
2332 | /* Generate AUDIT_PATH record with object. */ | |
2333 | name->type = AUDIT_TYPE_NORMAL; | |
2334 | audit_copy_inode(name, link->dentry, d_backing_inode(link->dentry)); | |
2335 | audit_log_name(current->audit_context, name, link, 0, NULL); | |
2336 | out: | |
2337 | kfree(name); | |
2338 | } | |
2339 | ||
2340 | /** | |
2341 | * audit_log_end - end one audit record | |
2342 | * @ab: the audit_buffer | |
2343 | * | |
2344 | * We can not do a netlink send inside an irq context because it blocks (last | |
2345 | * arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a | |
2346 | * queue and a tasklet is scheduled to remove them from the queue outside the | |
2347 | * irq context. May be called in any context. | |
2348 | */ | |
2349 | void audit_log_end(struct audit_buffer *ab) | |
2350 | { | |
2351 | struct sk_buff *skb; | |
2352 | struct nlmsghdr *nlh; | |
2353 | ||
2354 | if (!ab) | |
2355 | return; | |
2356 | ||
2357 | if (audit_rate_check()) { | |
2358 | skb = ab->skb; | |
2359 | ab->skb = NULL; | |
2360 | ||
2361 | /* setup the netlink header, see the comments in | |
2362 | * kauditd_send_multicast_skb() for length quirks */ | |
2363 | nlh = nlmsg_hdr(skb); | |
2364 | nlh->nlmsg_len = skb->len - NLMSG_HDRLEN; | |
2365 | ||
2366 | /* queue the netlink packet and poke the kauditd thread */ | |
2367 | skb_queue_tail(&audit_queue, skb); | |
2368 | wake_up_interruptible(&kauditd_wait); | |
2369 | } else | |
2370 | audit_log_lost("rate limit exceeded"); | |
2371 | ||
2372 | audit_buffer_free(ab); | |
2373 | } | |
2374 | ||
2375 | /** | |
2376 | * audit_log - Log an audit record | |
2377 | * @ctx: audit context | |
2378 | * @gfp_mask: type of allocation | |
2379 | * @type: audit message type | |
2380 | * @fmt: format string to use | |
2381 | * @...: variable parameters matching the format string | |
2382 | * | |
2383 | * This is a convenience function that calls audit_log_start, | |
2384 | * audit_log_vformat, and audit_log_end. It may be called | |
2385 | * in any context. | |
2386 | */ | |
2387 | void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type, | |
2388 | const char *fmt, ...) | |
2389 | { | |
2390 | struct audit_buffer *ab; | |
2391 | va_list args; | |
2392 | ||
2393 | ab = audit_log_start(ctx, gfp_mask, type); | |
2394 | if (ab) { | |
2395 | va_start(args, fmt); | |
2396 | audit_log_vformat(ab, fmt, args); | |
2397 | va_end(args); | |
2398 | audit_log_end(ab); | |
2399 | } | |
2400 | } | |
2401 | ||
2402 | EXPORT_SYMBOL(audit_log_start); | |
2403 | EXPORT_SYMBOL(audit_log_end); | |
2404 | EXPORT_SYMBOL(audit_log_format); | |
2405 | EXPORT_SYMBOL(audit_log); |