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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 = AUDIT_UNINITIALIZED; | |
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 | struct auditd_connection { | |
106 | struct pid *pid; | |
107 | u32 portid; | |
108 | struct net *net; | |
109 | struct rcu_head rcu; | |
110 | }; | |
111 | static struct auditd_connection __rcu *auditd_conn; | |
112 | static DEFINE_SPINLOCK(auditd_conn_lock); | |
113 | ||
114 | /* If audit_rate_limit is non-zero, limit the rate of sending audit records | |
115 | * to that number per second. This prevents DoS attacks, but results in | |
116 | * audit records being dropped. */ | |
117 | static u32 audit_rate_limit; | |
118 | ||
119 | /* Number of outstanding audit_buffers allowed. | |
120 | * When set to zero, this means unlimited. */ | |
121 | static u32 audit_backlog_limit = 64; | |
122 | #define AUDIT_BACKLOG_WAIT_TIME (60 * HZ) | |
123 | static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME; | |
124 | ||
125 | /* The identity of the user shutting down the audit system. */ | |
126 | static kuid_t audit_sig_uid = INVALID_UID; | |
127 | static pid_t audit_sig_pid = -1; | |
128 | struct lsmblob audit_sig_lsm; | |
129 | ||
130 | /* Records can be lost in several ways: | |
131 | 0) [suppressed in audit_alloc] | |
132 | 1) out of memory in audit_log_start [kmalloc of struct audit_buffer] | |
133 | 2) out of memory in audit_log_move [alloc_skb] | |
134 | 3) suppressed due to audit_rate_limit | |
135 | 4) suppressed due to audit_backlog_limit | |
136 | */ | |
137 | static atomic_t audit_lost = ATOMIC_INIT(0); | |
138 | ||
139 | /* Monotonically increasing sum of time the kernel has spent | |
140 | * waiting while the backlog limit is exceeded. | |
141 | */ | |
142 | static atomic_t audit_backlog_wait_time_actual = ATOMIC_INIT(0); | |
143 | ||
144 | /* Hash for inode-based rules */ | |
145 | struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS]; | |
146 | ||
147 | static struct kmem_cache *audit_buffer_cache; | |
148 | ||
149 | /* queue msgs to send via kauditd_task */ | |
150 | static struct sk_buff_head audit_queue; | |
151 | /* queue msgs due to temporary unicast send problems */ | |
152 | static struct sk_buff_head audit_retry_queue; | |
153 | /* queue msgs waiting for new auditd connection */ | |
154 | static struct sk_buff_head audit_hold_queue; | |
155 | ||
156 | /* queue servicing thread */ | |
157 | static struct task_struct *kauditd_task; | |
158 | static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait); | |
159 | ||
160 | /* waitqueue for callers who are blocked on the audit backlog */ | |
161 | static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait); | |
162 | ||
163 | static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION, | |
164 | .mask = -1, | |
165 | .features = 0, | |
166 | .lock = 0,}; | |
167 | ||
168 | static char *audit_feature_names[2] = { | |
169 | "only_unset_loginuid", | |
170 | "loginuid_immutable", | |
171 | }; | |
172 | ||
173 | /** | |
174 | * struct audit_ctl_mutex - serialize requests from userspace | |
175 | * @lock: the mutex used for locking | |
176 | * @owner: the task which owns the lock | |
177 | * | |
178 | * Description: | |
179 | * This is the lock struct used to ensure we only process userspace requests | |
180 | * in an orderly fashion. We can't simply use a mutex/lock here because we | |
181 | * need to track lock ownership so we don't end up blocking the lock owner in | |
182 | * audit_log_start() or similar. | |
183 | */ | |
184 | static struct audit_ctl_mutex { | |
185 | struct mutex lock; | |
186 | void *owner; | |
187 | } audit_cmd_mutex; | |
188 | ||
189 | /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting | |
190 | * audit records. Since printk uses a 1024 byte buffer, this buffer | |
191 | * should be at least that large. */ | |
192 | #define AUDIT_BUFSIZ 1024 | |
193 | ||
194 | /* The audit_buffer is used when formatting an audit record. The caller | |
195 | * locks briefly to get the record off the freelist or to allocate the | |
196 | * buffer, and locks briefly to send the buffer to the netlink layer or | |
197 | * to place it on a transmit queue. Multiple audit_buffers can be in | |
198 | * use simultaneously. */ | |
199 | struct audit_buffer { | |
200 | struct sk_buff *skb; /* formatted skb ready to send */ | |
201 | struct audit_context *ctx; /* NULL or associated context */ | |
202 | gfp_t gfp_mask; | |
203 | }; | |
204 | ||
205 | struct audit_reply { | |
206 | __u32 portid; | |
207 | struct net *net; | |
208 | struct sk_buff *skb; | |
209 | }; | |
210 | ||
211 | /** | |
212 | * auditd_test_task - Check to see if a given task is an audit daemon | |
213 | * @task: the task to check | |
214 | * | |
215 | * Description: | |
216 | * Return 1 if the task is a registered audit daemon, 0 otherwise. | |
217 | */ | |
218 | int auditd_test_task(struct task_struct *task) | |
219 | { | |
220 | int rc; | |
221 | struct auditd_connection *ac; | |
222 | ||
223 | rcu_read_lock(); | |
224 | ac = rcu_dereference(auditd_conn); | |
225 | rc = (ac && ac->pid == task_tgid(task) ? 1 : 0); | |
226 | rcu_read_unlock(); | |
227 | ||
228 | return rc; | |
229 | } | |
230 | ||
231 | /** | |
232 | * audit_ctl_lock - Take the audit control lock | |
233 | */ | |
234 | void audit_ctl_lock(void) | |
235 | { | |
236 | mutex_lock(&audit_cmd_mutex.lock); | |
237 | audit_cmd_mutex.owner = current; | |
238 | } | |
239 | ||
240 | /** | |
241 | * audit_ctl_unlock - Drop the audit control lock | |
242 | */ | |
243 | void audit_ctl_unlock(void) | |
244 | { | |
245 | audit_cmd_mutex.owner = NULL; | |
246 | mutex_unlock(&audit_cmd_mutex.lock); | |
247 | } | |
248 | ||
249 | /** | |
250 | * audit_ctl_owner_current - Test to see if the current task owns the lock | |
251 | * | |
252 | * Description: | |
253 | * Return true if the current task owns the audit control lock, false if it | |
254 | * doesn't own the lock. | |
255 | */ | |
256 | static bool audit_ctl_owner_current(void) | |
257 | { | |
258 | return (current == audit_cmd_mutex.owner); | |
259 | } | |
260 | ||
261 | /** | |
262 | * auditd_pid_vnr - Return the auditd PID relative to the namespace | |
263 | * | |
264 | * Description: | |
265 | * Returns the PID in relation to the namespace, 0 on failure. | |
266 | */ | |
267 | static pid_t auditd_pid_vnr(void) | |
268 | { | |
269 | pid_t pid; | |
270 | const struct auditd_connection *ac; | |
271 | ||
272 | rcu_read_lock(); | |
273 | ac = rcu_dereference(auditd_conn); | |
274 | if (!ac || !ac->pid) | |
275 | pid = 0; | |
276 | else | |
277 | pid = pid_vnr(ac->pid); | |
278 | rcu_read_unlock(); | |
279 | ||
280 | return pid; | |
281 | } | |
282 | ||
283 | /** | |
284 | * audit_get_sk - Return the audit socket for the given network namespace | |
285 | * @net: the destination network namespace | |
286 | * | |
287 | * Description: | |
288 | * Returns the sock pointer if valid, NULL otherwise. The caller must ensure | |
289 | * that a reference is held for the network namespace while the sock is in use. | |
290 | */ | |
291 | static struct sock *audit_get_sk(const struct net *net) | |
292 | { | |
293 | struct audit_net *aunet; | |
294 | ||
295 | if (!net) | |
296 | return NULL; | |
297 | ||
298 | aunet = net_generic(net, audit_net_id); | |
299 | return aunet->sk; | |
300 | } | |
301 | ||
302 | void audit_panic(const char *message) | |
303 | { | |
304 | switch (audit_failure) { | |
305 | case AUDIT_FAIL_SILENT: | |
306 | break; | |
307 | case AUDIT_FAIL_PRINTK: | |
308 | if (printk_ratelimit()) | |
309 | pr_err("%s\n", message); | |
310 | break; | |
311 | case AUDIT_FAIL_PANIC: | |
312 | panic("audit: %s\n", message); | |
313 | break; | |
314 | } | |
315 | } | |
316 | ||
317 | static inline int audit_rate_check(void) | |
318 | { | |
319 | static unsigned long last_check = 0; | |
320 | static int messages = 0; | |
321 | static DEFINE_SPINLOCK(lock); | |
322 | unsigned long flags; | |
323 | unsigned long now; | |
324 | unsigned long elapsed; | |
325 | int retval = 0; | |
326 | ||
327 | if (!audit_rate_limit) return 1; | |
328 | ||
329 | spin_lock_irqsave(&lock, flags); | |
330 | if (++messages < audit_rate_limit) { | |
331 | retval = 1; | |
332 | } else { | |
333 | now = jiffies; | |
334 | elapsed = now - last_check; | |
335 | if (elapsed > HZ) { | |
336 | last_check = now; | |
337 | messages = 0; | |
338 | retval = 1; | |
339 | } | |
340 | } | |
341 | spin_unlock_irqrestore(&lock, flags); | |
342 | ||
343 | return retval; | |
344 | } | |
345 | ||
346 | /** | |
347 | * audit_log_lost - conditionally log lost audit message event | |
348 | * @message: the message stating reason for lost audit message | |
349 | * | |
350 | * Emit at least 1 message per second, even if audit_rate_check is | |
351 | * throttling. | |
352 | * Always increment the lost messages counter. | |
353 | */ | |
354 | void audit_log_lost(const char *message) | |
355 | { | |
356 | static unsigned long last_msg = 0; | |
357 | static DEFINE_SPINLOCK(lock); | |
358 | unsigned long flags; | |
359 | unsigned long now; | |
360 | int print; | |
361 | ||
362 | atomic_inc(&audit_lost); | |
363 | ||
364 | print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit); | |
365 | ||
366 | if (!print) { | |
367 | spin_lock_irqsave(&lock, flags); | |
368 | now = jiffies; | |
369 | if (now - last_msg > HZ) { | |
370 | print = 1; | |
371 | last_msg = now; | |
372 | } | |
373 | spin_unlock_irqrestore(&lock, flags); | |
374 | } | |
375 | ||
376 | if (print) { | |
377 | if (printk_ratelimit()) | |
378 | pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n", | |
379 | atomic_read(&audit_lost), | |
380 | audit_rate_limit, | |
381 | audit_backlog_limit); | |
382 | audit_panic(message); | |
383 | } | |
384 | } | |
385 | ||
386 | static int audit_log_config_change(char *function_name, u32 new, u32 old, | |
387 | int allow_changes) | |
388 | { | |
389 | struct audit_buffer *ab; | |
390 | int rc = 0; | |
391 | ||
392 | ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE); | |
393 | if (unlikely(!ab)) | |
394 | return rc; | |
395 | audit_log_format(ab, "op=set %s=%u old=%u ", function_name, new, old); | |
396 | audit_log_session_info(ab); | |
397 | rc = audit_log_task_context(ab, NULL); | |
398 | if (rc) | |
399 | allow_changes = 0; /* Something weird, deny request */ | |
400 | audit_log_format(ab, " res=%d", allow_changes); | |
401 | audit_log_lsm(NULL, false); | |
402 | audit_log_end(ab); | |
403 | return rc; | |
404 | } | |
405 | ||
406 | static int audit_do_config_change(char *function_name, u32 *to_change, u32 new) | |
407 | { | |
408 | int allow_changes, rc = 0; | |
409 | u32 old = *to_change; | |
410 | ||
411 | /* check if we are locked */ | |
412 | if (audit_enabled == AUDIT_LOCKED) | |
413 | allow_changes = 0; | |
414 | else | |
415 | allow_changes = 1; | |
416 | ||
417 | if (audit_enabled != AUDIT_OFF) { | |
418 | rc = audit_log_config_change(function_name, new, old, allow_changes); | |
419 | if (rc) | |
420 | allow_changes = 0; | |
421 | } | |
422 | ||
423 | /* If we are allowed, make the change */ | |
424 | if (allow_changes == 1) | |
425 | *to_change = new; | |
426 | /* Not allowed, update reason */ | |
427 | else if (rc == 0) | |
428 | rc = -EPERM; | |
429 | return rc; | |
430 | } | |
431 | ||
432 | static int audit_set_rate_limit(u32 limit) | |
433 | { | |
434 | return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit); | |
435 | } | |
436 | ||
437 | static int audit_set_backlog_limit(u32 limit) | |
438 | { | |
439 | return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit); | |
440 | } | |
441 | ||
442 | static int audit_set_backlog_wait_time(u32 timeout) | |
443 | { | |
444 | return audit_do_config_change("audit_backlog_wait_time", | |
445 | &audit_backlog_wait_time, timeout); | |
446 | } | |
447 | ||
448 | static int audit_set_enabled(u32 state) | |
449 | { | |
450 | int rc; | |
451 | if (state > AUDIT_LOCKED) | |
452 | return -EINVAL; | |
453 | ||
454 | rc = audit_do_config_change("audit_enabled", &audit_enabled, state); | |
455 | if (!rc) | |
456 | audit_ever_enabled |= !!state; | |
457 | ||
458 | return rc; | |
459 | } | |
460 | ||
461 | static int audit_set_failure(u32 state) | |
462 | { | |
463 | if (state != AUDIT_FAIL_SILENT | |
464 | && state != AUDIT_FAIL_PRINTK | |
465 | && state != AUDIT_FAIL_PANIC) | |
466 | return -EINVAL; | |
467 | ||
468 | return audit_do_config_change("audit_failure", &audit_failure, state); | |
469 | } | |
470 | ||
471 | /** | |
472 | * auditd_conn_free - RCU helper to release an auditd connection struct | |
473 | * @rcu: RCU head | |
474 | * | |
475 | * Description: | |
476 | * Drop any references inside the auditd connection tracking struct and free | |
477 | * the memory. | |
478 | */ | |
479 | static void auditd_conn_free(struct rcu_head *rcu) | |
480 | { | |
481 | struct auditd_connection *ac; | |
482 | ||
483 | ac = container_of(rcu, struct auditd_connection, rcu); | |
484 | put_pid(ac->pid); | |
485 | put_net(ac->net); | |
486 | kfree(ac); | |
487 | } | |
488 | ||
489 | /** | |
490 | * auditd_set - Set/Reset the auditd connection state | |
491 | * @pid: auditd PID | |
492 | * @portid: auditd netlink portid | |
493 | * @net: auditd network namespace pointer | |
494 | * | |
495 | * Description: | |
496 | * This function will obtain and drop network namespace references as | |
497 | * necessary. Returns zero on success, negative values on failure. | |
498 | */ | |
499 | static int auditd_set(struct pid *pid, u32 portid, struct net *net) | |
500 | { | |
501 | unsigned long flags; | |
502 | struct auditd_connection *ac_old, *ac_new; | |
503 | ||
504 | if (!pid || !net) | |
505 | return -EINVAL; | |
506 | ||
507 | ac_new = kzalloc(sizeof(*ac_new), GFP_KERNEL); | |
508 | if (!ac_new) | |
509 | return -ENOMEM; | |
510 | ac_new->pid = get_pid(pid); | |
511 | ac_new->portid = portid; | |
512 | ac_new->net = get_net(net); | |
513 | ||
514 | spin_lock_irqsave(&auditd_conn_lock, flags); | |
515 | ac_old = rcu_dereference_protected(auditd_conn, | |
516 | lockdep_is_held(&auditd_conn_lock)); | |
517 | rcu_assign_pointer(auditd_conn, ac_new); | |
518 | spin_unlock_irqrestore(&auditd_conn_lock, flags); | |
519 | ||
520 | if (ac_old) | |
521 | call_rcu(&ac_old->rcu, auditd_conn_free); | |
522 | ||
523 | return 0; | |
524 | } | |
525 | ||
526 | /** | |
527 | * kauditd_printk_skb - Print the audit record to the ring buffer | |
528 | * @skb: audit record | |
529 | * | |
530 | * Whatever the reason, this packet may not make it to the auditd connection | |
531 | * so write it via printk so the information isn't completely lost. | |
532 | */ | |
533 | static void kauditd_printk_skb(struct sk_buff *skb) | |
534 | { | |
535 | struct nlmsghdr *nlh = nlmsg_hdr(skb); | |
536 | char *data = nlmsg_data(nlh); | |
537 | ||
538 | if (nlh->nlmsg_type != AUDIT_EOE && printk_ratelimit()) | |
539 | pr_notice("type=%d %s\n", nlh->nlmsg_type, data); | |
540 | } | |
541 | ||
542 | /** | |
543 | * kauditd_rehold_skb - Handle a audit record send failure in the hold queue | |
544 | * @skb: audit record | |
545 | * @error: error code (unused) | |
546 | * | |
547 | * Description: | |
548 | * This should only be used by the kauditd_thread when it fails to flush the | |
549 | * hold queue. | |
550 | */ | |
551 | static void kauditd_rehold_skb(struct sk_buff *skb, __always_unused int error) | |
552 | { | |
553 | /* put the record back in the queue */ | |
554 | skb_queue_tail(&audit_hold_queue, skb); | |
555 | } | |
556 | ||
557 | /** | |
558 | * kauditd_hold_skb - Queue an audit record, waiting for auditd | |
559 | * @skb: audit record | |
560 | * @error: error code | |
561 | * | |
562 | * Description: | |
563 | * Queue the audit record, waiting for an instance of auditd. When this | |
564 | * function is called we haven't given up yet on sending the record, but things | |
565 | * are not looking good. The first thing we want to do is try to write the | |
566 | * record via printk and then see if we want to try and hold on to the record | |
567 | * and queue it, if we have room. If we want to hold on to the record, but we | |
568 | * don't have room, record a record lost message. | |
569 | */ | |
570 | static void kauditd_hold_skb(struct sk_buff *skb, int error) | |
571 | { | |
572 | /* at this point it is uncertain if we will ever send this to auditd so | |
573 | * try to send the message via printk before we go any further */ | |
574 | kauditd_printk_skb(skb); | |
575 | ||
576 | /* can we just silently drop the message? */ | |
577 | if (!audit_default) | |
578 | goto drop; | |
579 | ||
580 | /* the hold queue is only for when the daemon goes away completely, | |
581 | * not -EAGAIN failures; if we are in a -EAGAIN state requeue the | |
582 | * record on the retry queue unless it's full, in which case drop it | |
583 | */ | |
584 | if (error == -EAGAIN) { | |
585 | if (!audit_backlog_limit || | |
586 | skb_queue_len(&audit_retry_queue) < audit_backlog_limit) { | |
587 | skb_queue_tail(&audit_retry_queue, skb); | |
588 | return; | |
589 | } | |
590 | audit_log_lost("kauditd retry queue overflow"); | |
591 | goto drop; | |
592 | } | |
593 | ||
594 | /* if we have room in the hold queue, queue the message */ | |
595 | if (!audit_backlog_limit || | |
596 | skb_queue_len(&audit_hold_queue) < audit_backlog_limit) { | |
597 | skb_queue_tail(&audit_hold_queue, skb); | |
598 | return; | |
599 | } | |
600 | ||
601 | /* we have no other options - drop the message */ | |
602 | audit_log_lost("kauditd hold queue overflow"); | |
603 | drop: | |
604 | kfree_skb(skb); | |
605 | } | |
606 | ||
607 | /** | |
608 | * kauditd_retry_skb - Queue an audit record, attempt to send again to auditd | |
609 | * @skb: audit record | |
610 | * @error: error code (unused) | |
611 | * | |
612 | * Description: | |
613 | * Not as serious as kauditd_hold_skb() as we still have a connected auditd, | |
614 | * but for some reason we are having problems sending it audit records so | |
615 | * queue the given record and attempt to resend. | |
616 | */ | |
617 | static void kauditd_retry_skb(struct sk_buff *skb, __always_unused int error) | |
618 | { | |
619 | if (!audit_backlog_limit || | |
620 | skb_queue_len(&audit_retry_queue) < audit_backlog_limit) { | |
621 | skb_queue_tail(&audit_retry_queue, skb); | |
622 | return; | |
623 | } | |
624 | ||
625 | /* we have to drop the record, send it via printk as a last effort */ | |
626 | kauditd_printk_skb(skb); | |
627 | audit_log_lost("kauditd retry queue overflow"); | |
628 | kfree_skb(skb); | |
629 | } | |
630 | ||
631 | /** | |
632 | * auditd_reset - Disconnect the auditd connection | |
633 | * @ac: auditd connection state | |
634 | * | |
635 | * Description: | |
636 | * Break the auditd/kauditd connection and move all the queued records into the | |
637 | * hold queue in case auditd reconnects. It is important to note that the @ac | |
638 | * pointer should never be dereferenced inside this function as it may be NULL | |
639 | * or invalid, you can only compare the memory address! If @ac is NULL then | |
640 | * the connection will always be reset. | |
641 | */ | |
642 | static void auditd_reset(const struct auditd_connection *ac) | |
643 | { | |
644 | unsigned long flags; | |
645 | struct sk_buff *skb; | |
646 | struct auditd_connection *ac_old; | |
647 | ||
648 | /* if it isn't already broken, break the connection */ | |
649 | spin_lock_irqsave(&auditd_conn_lock, flags); | |
650 | ac_old = rcu_dereference_protected(auditd_conn, | |
651 | lockdep_is_held(&auditd_conn_lock)); | |
652 | if (ac && ac != ac_old) { | |
653 | /* someone already registered a new auditd connection */ | |
654 | spin_unlock_irqrestore(&auditd_conn_lock, flags); | |
655 | return; | |
656 | } | |
657 | rcu_assign_pointer(auditd_conn, NULL); | |
658 | spin_unlock_irqrestore(&auditd_conn_lock, flags); | |
659 | ||
660 | if (ac_old) | |
661 | call_rcu(&ac_old->rcu, auditd_conn_free); | |
662 | ||
663 | /* flush the retry queue to the hold queue, but don't touch the main | |
664 | * queue since we need to process that normally for multicast */ | |
665 | while ((skb = skb_dequeue(&audit_retry_queue))) | |
666 | kauditd_hold_skb(skb, -ECONNREFUSED); | |
667 | } | |
668 | ||
669 | /** | |
670 | * auditd_send_unicast_skb - Send a record via unicast to auditd | |
671 | * @skb: audit record | |
672 | * | |
673 | * Description: | |
674 | * Send a skb to the audit daemon, returns positive/zero values on success and | |
675 | * negative values on failure; in all cases the skb will be consumed by this | |
676 | * function. If the send results in -ECONNREFUSED the connection with auditd | |
677 | * will be reset. This function may sleep so callers should not hold any locks | |
678 | * where this would cause a problem. | |
679 | */ | |
680 | static int auditd_send_unicast_skb(struct sk_buff *skb) | |
681 | { | |
682 | int rc; | |
683 | u32 portid; | |
684 | struct net *net; | |
685 | struct sock *sk; | |
686 | struct auditd_connection *ac; | |
687 | ||
688 | /* NOTE: we can't call netlink_unicast while in the RCU section so | |
689 | * take a reference to the network namespace and grab local | |
690 | * copies of the namespace, the sock, and the portid; the | |
691 | * namespace and sock aren't going to go away while we hold a | |
692 | * reference and if the portid does become invalid after the RCU | |
693 | * section netlink_unicast() should safely return an error */ | |
694 | ||
695 | rcu_read_lock(); | |
696 | ac = rcu_dereference(auditd_conn); | |
697 | if (!ac) { | |
698 | rcu_read_unlock(); | |
699 | kfree_skb(skb); | |
700 | rc = -ECONNREFUSED; | |
701 | goto err; | |
702 | } | |
703 | net = get_net(ac->net); | |
704 | sk = audit_get_sk(net); | |
705 | portid = ac->portid; | |
706 | rcu_read_unlock(); | |
707 | ||
708 | rc = netlink_unicast(sk, skb, portid, 0); | |
709 | put_net(net); | |
710 | if (rc < 0) | |
711 | goto err; | |
712 | ||
713 | return rc; | |
714 | ||
715 | err: | |
716 | if (ac && rc == -ECONNREFUSED) | |
717 | auditd_reset(ac); | |
718 | return rc; | |
719 | } | |
720 | ||
721 | /** | |
722 | * kauditd_send_queue - Helper for kauditd_thread to flush skb queues | |
723 | * @sk: the sending sock | |
724 | * @portid: the netlink destination | |
725 | * @queue: the skb queue to process | |
726 | * @retry_limit: limit on number of netlink unicast failures | |
727 | * @skb_hook: per-skb hook for additional processing | |
728 | * @err_hook: hook called if the skb fails the netlink unicast send | |
729 | * | |
730 | * Description: | |
731 | * Run through the given queue and attempt to send the audit records to auditd, | |
732 | * returns zero on success, negative values on failure. It is up to the caller | |
733 | * to ensure that the @sk is valid for the duration of this function. | |
734 | * | |
735 | */ | |
736 | static int kauditd_send_queue(struct sock *sk, u32 portid, | |
737 | struct sk_buff_head *queue, | |
738 | unsigned int retry_limit, | |
739 | void (*skb_hook)(struct sk_buff *skb), | |
740 | void (*err_hook)(struct sk_buff *skb, int error)) | |
741 | { | |
742 | int rc = 0; | |
743 | struct sk_buff *skb = NULL; | |
744 | struct sk_buff *skb_tail; | |
745 | unsigned int failed = 0; | |
746 | ||
747 | /* NOTE: kauditd_thread takes care of all our locking, we just use | |
748 | * the netlink info passed to us (e.g. sk and portid) */ | |
749 | ||
750 | skb_tail = skb_peek_tail(queue); | |
751 | while ((skb != skb_tail) && (skb = skb_dequeue(queue))) { | |
752 | /* call the skb_hook for each skb we touch */ | |
753 | if (skb_hook) | |
754 | (*skb_hook)(skb); | |
755 | ||
756 | /* can we send to anyone via unicast? */ | |
757 | if (!sk) { | |
758 | if (err_hook) | |
759 | (*err_hook)(skb, -ECONNREFUSED); | |
760 | continue; | |
761 | } | |
762 | ||
763 | retry: | |
764 | /* grab an extra skb reference in case of error */ | |
765 | skb_get(skb); | |
766 | rc = netlink_unicast(sk, skb, portid, 0); | |
767 | if (rc < 0) { | |
768 | /* send failed - try a few times unless fatal error */ | |
769 | if (++failed >= retry_limit || | |
770 | rc == -ECONNREFUSED || rc == -EPERM) { | |
771 | sk = NULL; | |
772 | if (err_hook) | |
773 | (*err_hook)(skb, rc); | |
774 | if (rc == -EAGAIN) | |
775 | rc = 0; | |
776 | /* continue to drain the queue */ | |
777 | continue; | |
778 | } else | |
779 | goto retry; | |
780 | } else { | |
781 | /* skb sent - drop the extra reference and continue */ | |
782 | consume_skb(skb); | |
783 | failed = 0; | |
784 | } | |
785 | } | |
786 | ||
787 | return (rc >= 0 ? 0 : rc); | |
788 | } | |
789 | ||
790 | /* | |
791 | * kauditd_send_multicast_skb - Send a record to any multicast listeners | |
792 | * @skb: audit record | |
793 | * | |
794 | * Description: | |
795 | * Write a multicast message to anyone listening in the initial network | |
796 | * namespace. This function doesn't consume an skb as might be expected since | |
797 | * it has to copy it anyways. | |
798 | */ | |
799 | static void kauditd_send_multicast_skb(struct sk_buff *skb) | |
800 | { | |
801 | struct sk_buff *copy; | |
802 | struct sock *sock = audit_get_sk(&init_net); | |
803 | struct nlmsghdr *nlh; | |
804 | ||
805 | /* NOTE: we are not taking an additional reference for init_net since | |
806 | * we don't have to worry about it going away */ | |
807 | ||
808 | if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG)) | |
809 | return; | |
810 | ||
811 | /* | |
812 | * The seemingly wasteful skb_copy() rather than bumping the refcount | |
813 | * using skb_get() is necessary because non-standard mods are made to | |
814 | * the skb by the original kaudit unicast socket send routine. The | |
815 | * existing auditd daemon assumes this breakage. Fixing this would | |
816 | * require co-ordinating a change in the established protocol between | |
817 | * the kaudit kernel subsystem and the auditd userspace code. There is | |
818 | * no reason for new multicast clients to continue with this | |
819 | * non-compliance. | |
820 | */ | |
821 | copy = skb_copy(skb, GFP_KERNEL); | |
822 | if (!copy) | |
823 | return; | |
824 | nlh = nlmsg_hdr(copy); | |
825 | nlh->nlmsg_len = skb->len; | |
826 | ||
827 | nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL); | |
828 | } | |
829 | ||
830 | /** | |
831 | * kauditd_thread - Worker thread to send audit records to userspace | |
832 | * @dummy: unused | |
833 | */ | |
834 | static int kauditd_thread(void *dummy) | |
835 | { | |
836 | int rc; | |
837 | u32 portid = 0; | |
838 | struct net *net = NULL; | |
839 | struct sock *sk = NULL; | |
840 | struct auditd_connection *ac; | |
841 | ||
842 | #define UNICAST_RETRIES 5 | |
843 | ||
844 | set_freezable(); | |
845 | while (!kthread_should_stop()) { | |
846 | /* NOTE: see the lock comments in auditd_send_unicast_skb() */ | |
847 | rcu_read_lock(); | |
848 | ac = rcu_dereference(auditd_conn); | |
849 | if (!ac) { | |
850 | rcu_read_unlock(); | |
851 | goto main_queue; | |
852 | } | |
853 | net = get_net(ac->net); | |
854 | sk = audit_get_sk(net); | |
855 | portid = ac->portid; | |
856 | rcu_read_unlock(); | |
857 | ||
858 | /* attempt to flush the hold queue */ | |
859 | rc = kauditd_send_queue(sk, portid, | |
860 | &audit_hold_queue, UNICAST_RETRIES, | |
861 | NULL, kauditd_rehold_skb); | |
862 | if (rc < 0) { | |
863 | sk = NULL; | |
864 | auditd_reset(ac); | |
865 | goto main_queue; | |
866 | } | |
867 | ||
868 | /* attempt to flush the retry queue */ | |
869 | rc = kauditd_send_queue(sk, portid, | |
870 | &audit_retry_queue, UNICAST_RETRIES, | |
871 | NULL, kauditd_hold_skb); | |
872 | if (rc < 0) { | |
873 | sk = NULL; | |
874 | auditd_reset(ac); | |
875 | goto main_queue; | |
876 | } | |
877 | ||
878 | main_queue: | |
879 | /* process the main queue - do the multicast send and attempt | |
880 | * unicast, dump failed record sends to the retry queue; if | |
881 | * sk == NULL due to previous failures we will just do the | |
882 | * multicast send and move the record to the hold queue */ | |
883 | rc = kauditd_send_queue(sk, portid, &audit_queue, 1, | |
884 | kauditd_send_multicast_skb, | |
885 | (sk ? | |
886 | kauditd_retry_skb : kauditd_hold_skb)); | |
887 | if (ac && rc < 0) | |
888 | auditd_reset(ac); | |
889 | sk = NULL; | |
890 | ||
891 | /* drop our netns reference, no auditd sends past this line */ | |
892 | if (net) { | |
893 | put_net(net); | |
894 | net = NULL; | |
895 | } | |
896 | ||
897 | /* we have processed all the queues so wake everyone */ | |
898 | wake_up(&audit_backlog_wait); | |
899 | ||
900 | /* NOTE: we want to wake up if there is anything on the queue, | |
901 | * regardless of if an auditd is connected, as we need to | |
902 | * do the multicast send and rotate records from the | |
903 | * main queue to the retry/hold queues */ | |
904 | wait_event_freezable(kauditd_wait, | |
905 | (skb_queue_len(&audit_queue) ? 1 : 0)); | |
906 | } | |
907 | ||
908 | return 0; | |
909 | } | |
910 | ||
911 | int audit_send_list_thread(void *_dest) | |
912 | { | |
913 | struct audit_netlink_list *dest = _dest; | |
914 | struct sk_buff *skb; | |
915 | struct sock *sk = audit_get_sk(dest->net); | |
916 | ||
917 | /* wait for parent to finish and send an ACK */ | |
918 | audit_ctl_lock(); | |
919 | audit_ctl_unlock(); | |
920 | ||
921 | while ((skb = __skb_dequeue(&dest->q)) != NULL) | |
922 | netlink_unicast(sk, skb, dest->portid, 0); | |
923 | ||
924 | put_net(dest->net); | |
925 | kfree(dest); | |
926 | ||
927 | return 0; | |
928 | } | |
929 | ||
930 | struct sk_buff *audit_make_reply(int seq, int type, int done, | |
931 | int multi, const void *payload, int size) | |
932 | { | |
933 | struct sk_buff *skb; | |
934 | struct nlmsghdr *nlh; | |
935 | void *data; | |
936 | int flags = multi ? NLM_F_MULTI : 0; | |
937 | int t = done ? NLMSG_DONE : type; | |
938 | ||
939 | skb = nlmsg_new(size, GFP_KERNEL); | |
940 | if (!skb) | |
941 | return NULL; | |
942 | ||
943 | nlh = nlmsg_put(skb, 0, seq, t, size, flags); | |
944 | if (!nlh) | |
945 | goto out_kfree_skb; | |
946 | data = nlmsg_data(nlh); | |
947 | memcpy(data, payload, size); | |
948 | return skb; | |
949 | ||
950 | out_kfree_skb: | |
951 | kfree_skb(skb); | |
952 | return NULL; | |
953 | } | |
954 | ||
955 | static void audit_free_reply(struct audit_reply *reply) | |
956 | { | |
957 | if (!reply) | |
958 | return; | |
959 | ||
960 | kfree_skb(reply->skb); | |
961 | if (reply->net) | |
962 | put_net(reply->net); | |
963 | kfree(reply); | |
964 | } | |
965 | ||
966 | static int audit_send_reply_thread(void *arg) | |
967 | { | |
968 | struct audit_reply *reply = (struct audit_reply *)arg; | |
969 | ||
970 | audit_ctl_lock(); | |
971 | audit_ctl_unlock(); | |
972 | ||
973 | /* Ignore failure. It'll only happen if the sender goes away, | |
974 | because our timeout is set to infinite. */ | |
975 | netlink_unicast(audit_get_sk(reply->net), reply->skb, reply->portid, 0); | |
976 | reply->skb = NULL; | |
977 | audit_free_reply(reply); | |
978 | return 0; | |
979 | } | |
980 | ||
981 | /** | |
982 | * audit_send_reply - send an audit reply message via netlink | |
983 | * @request_skb: skb of request we are replying to (used to target the reply) | |
984 | * @seq: sequence number | |
985 | * @type: audit message type | |
986 | * @done: done (last) flag | |
987 | * @multi: multi-part message flag | |
988 | * @payload: payload data | |
989 | * @size: payload size | |
990 | * | |
991 | * Allocates a skb, builds the netlink message, and sends it to the port id. | |
992 | */ | |
993 | static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done, | |
994 | int multi, const void *payload, int size) | |
995 | { | |
996 | struct task_struct *tsk; | |
997 | struct audit_reply *reply; | |
998 | ||
999 | reply = kzalloc(sizeof(*reply), GFP_KERNEL); | |
1000 | if (!reply) | |
1001 | return; | |
1002 | ||
1003 | reply->skb = audit_make_reply(seq, type, done, multi, payload, size); | |
1004 | if (!reply->skb) | |
1005 | goto err; | |
1006 | reply->net = get_net(sock_net(NETLINK_CB(request_skb).sk)); | |
1007 | reply->portid = NETLINK_CB(request_skb).portid; | |
1008 | ||
1009 | tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply"); | |
1010 | if (IS_ERR(tsk)) | |
1011 | goto err; | |
1012 | ||
1013 | return; | |
1014 | ||
1015 | err: | |
1016 | audit_free_reply(reply); | |
1017 | } | |
1018 | ||
1019 | /* | |
1020 | * Check for appropriate CAP_AUDIT_ capabilities on incoming audit | |
1021 | * control messages. | |
1022 | */ | |
1023 | static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type) | |
1024 | { | |
1025 | int err = 0; | |
1026 | ||
1027 | /* Only support initial user namespace for now. */ | |
1028 | /* | |
1029 | * We return ECONNREFUSED because it tricks userspace into thinking | |
1030 | * that audit was not configured into the kernel. Lots of users | |
1031 | * configure their PAM stack (because that's what the distro does) | |
1032 | * to reject login if unable to send messages to audit. If we return | |
1033 | * ECONNREFUSED the PAM stack thinks the kernel does not have audit | |
1034 | * configured in and will let login proceed. If we return EPERM | |
1035 | * userspace will reject all logins. This should be removed when we | |
1036 | * support non init namespaces!! | |
1037 | */ | |
1038 | if (current_user_ns() != &init_user_ns) | |
1039 | return -ECONNREFUSED; | |
1040 | ||
1041 | switch (msg_type) { | |
1042 | case AUDIT_LIST: | |
1043 | case AUDIT_ADD: | |
1044 | case AUDIT_DEL: | |
1045 | return -EOPNOTSUPP; | |
1046 | case AUDIT_GET: | |
1047 | case AUDIT_SET: | |
1048 | case AUDIT_GET_FEATURE: | |
1049 | case AUDIT_SET_FEATURE: | |
1050 | case AUDIT_LIST_RULES: | |
1051 | case AUDIT_ADD_RULE: | |
1052 | case AUDIT_DEL_RULE: | |
1053 | case AUDIT_SIGNAL_INFO: | |
1054 | case AUDIT_TTY_GET: | |
1055 | case AUDIT_TTY_SET: | |
1056 | case AUDIT_TRIM: | |
1057 | case AUDIT_MAKE_EQUIV: | |
1058 | /* Only support auditd and auditctl in initial pid namespace | |
1059 | * for now. */ | |
1060 | if (task_active_pid_ns(current) != &init_pid_ns) | |
1061 | return -EPERM; | |
1062 | ||
1063 | if (!netlink_capable(skb, CAP_AUDIT_CONTROL)) | |
1064 | err = -EPERM; | |
1065 | break; | |
1066 | case AUDIT_USER: | |
1067 | case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG: | |
1068 | case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2: | |
1069 | if (!netlink_capable(skb, CAP_AUDIT_WRITE)) | |
1070 | err = -EPERM; | |
1071 | break; | |
1072 | default: /* bad msg */ | |
1073 | err = -EINVAL; | |
1074 | } | |
1075 | ||
1076 | return err; | |
1077 | } | |
1078 | ||
1079 | static void audit_log_common_recv_msg(struct audit_context *context, | |
1080 | struct audit_buffer **ab, u16 msg_type) | |
1081 | { | |
1082 | uid_t uid = from_kuid(&init_user_ns, current_uid()); | |
1083 | pid_t pid = task_tgid_nr(current); | |
1084 | ||
1085 | if (!audit_enabled && msg_type != AUDIT_USER_AVC) { | |
1086 | *ab = NULL; | |
1087 | return; | |
1088 | } | |
1089 | ||
1090 | *ab = audit_log_start(context, GFP_KERNEL, msg_type); | |
1091 | if (unlikely(!*ab)) | |
1092 | return; | |
1093 | audit_log_format(*ab, "pid=%d uid=%u ", pid, uid); | |
1094 | audit_log_session_info(*ab); | |
1095 | audit_log_task_context(*ab, NULL); | |
1096 | } | |
1097 | ||
1098 | static inline void audit_log_user_recv_msg(struct audit_buffer **ab, | |
1099 | u16 msg_type) | |
1100 | { | |
1101 | struct audit_context *context; | |
1102 | ||
1103 | if (!lsm_multiple_contexts()) { | |
1104 | audit_log_common_recv_msg(NULL, ab, msg_type); | |
1105 | return; | |
1106 | } | |
1107 | ||
1108 | context = audit_context(); | |
1109 | if (context) { | |
1110 | if (!context->in_syscall) | |
1111 | audit_stamp_context(context); | |
1112 | audit_log_common_recv_msg(context, ab, msg_type); | |
1113 | return; | |
1114 | } | |
1115 | ||
1116 | audit_alloc(current); | |
1117 | context = audit_context(); | |
1118 | ||
1119 | audit_log_common_recv_msg(context, ab, msg_type); | |
1120 | } | |
1121 | ||
1122 | int is_audit_feature_set(int i) | |
1123 | { | |
1124 | return af.features & AUDIT_FEATURE_TO_MASK(i); | |
1125 | } | |
1126 | ||
1127 | ||
1128 | static int audit_get_feature(struct sk_buff *skb) | |
1129 | { | |
1130 | u32 seq; | |
1131 | ||
1132 | seq = nlmsg_hdr(skb)->nlmsg_seq; | |
1133 | ||
1134 | audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af)); | |
1135 | ||
1136 | return 0; | |
1137 | } | |
1138 | ||
1139 | static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature, | |
1140 | u32 old_lock, u32 new_lock, int res) | |
1141 | { | |
1142 | struct audit_buffer *ab; | |
1143 | ||
1144 | if (audit_enabled == AUDIT_OFF) | |
1145 | return; | |
1146 | ||
1147 | ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_FEATURE_CHANGE); | |
1148 | if (!ab) | |
1149 | return; | |
1150 | audit_log_task_info(ab); | |
1151 | audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d", | |
1152 | audit_feature_names[which], !!old_feature, !!new_feature, | |
1153 | !!old_lock, !!new_lock, res); | |
1154 | audit_log_end(ab); | |
1155 | } | |
1156 | ||
1157 | static int audit_set_feature(struct audit_features *uaf) | |
1158 | { | |
1159 | int i; | |
1160 | ||
1161 | BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names)); | |
1162 | ||
1163 | /* if there is ever a version 2 we should handle that here */ | |
1164 | ||
1165 | for (i = 0; i <= AUDIT_LAST_FEATURE; i++) { | |
1166 | u32 feature = AUDIT_FEATURE_TO_MASK(i); | |
1167 | u32 old_feature, new_feature, old_lock, new_lock; | |
1168 | ||
1169 | /* if we are not changing this feature, move along */ | |
1170 | if (!(feature & uaf->mask)) | |
1171 | continue; | |
1172 | ||
1173 | old_feature = af.features & feature; | |
1174 | new_feature = uaf->features & feature; | |
1175 | new_lock = (uaf->lock | af.lock) & feature; | |
1176 | old_lock = af.lock & feature; | |
1177 | ||
1178 | /* are we changing a locked feature? */ | |
1179 | if (old_lock && (new_feature != old_feature)) { | |
1180 | audit_log_feature_change(i, old_feature, new_feature, | |
1181 | old_lock, new_lock, 0); | |
1182 | return -EPERM; | |
1183 | } | |
1184 | } | |
1185 | /* nothing invalid, do the changes */ | |
1186 | for (i = 0; i <= AUDIT_LAST_FEATURE; i++) { | |
1187 | u32 feature = AUDIT_FEATURE_TO_MASK(i); | |
1188 | u32 old_feature, new_feature, old_lock, new_lock; | |
1189 | ||
1190 | /* if we are not changing this feature, move along */ | |
1191 | if (!(feature & uaf->mask)) | |
1192 | continue; | |
1193 | ||
1194 | old_feature = af.features & feature; | |
1195 | new_feature = uaf->features & feature; | |
1196 | old_lock = af.lock & feature; | |
1197 | new_lock = (uaf->lock | af.lock) & feature; | |
1198 | ||
1199 | if (new_feature != old_feature) | |
1200 | audit_log_feature_change(i, old_feature, new_feature, | |
1201 | old_lock, new_lock, 1); | |
1202 | ||
1203 | if (new_feature) | |
1204 | af.features |= feature; | |
1205 | else | |
1206 | af.features &= ~feature; | |
1207 | af.lock |= new_lock; | |
1208 | } | |
1209 | ||
1210 | return 0; | |
1211 | } | |
1212 | ||
1213 | static int audit_replace(struct pid *pid) | |
1214 | { | |
1215 | pid_t pvnr; | |
1216 | struct sk_buff *skb; | |
1217 | ||
1218 | pvnr = pid_vnr(pid); | |
1219 | skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pvnr, sizeof(pvnr)); | |
1220 | if (!skb) | |
1221 | return -ENOMEM; | |
1222 | return auditd_send_unicast_skb(skb); | |
1223 | } | |
1224 | ||
1225 | static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) | |
1226 | { | |
1227 | u32 seq; | |
1228 | void *data; | |
1229 | int data_len; | |
1230 | int err; | |
1231 | struct audit_buffer *ab; | |
1232 | u16 msg_type = nlh->nlmsg_type; | |
1233 | struct audit_sig_info *sig_data; | |
1234 | ||
1235 | err = audit_netlink_ok(skb, msg_type); | |
1236 | if (err) | |
1237 | return err; | |
1238 | ||
1239 | seq = nlh->nlmsg_seq; | |
1240 | data = nlmsg_data(nlh); | |
1241 | data_len = nlmsg_len(nlh); | |
1242 | ||
1243 | switch (msg_type) { | |
1244 | case AUDIT_GET: { | |
1245 | struct audit_status s; | |
1246 | memset(&s, 0, sizeof(s)); | |
1247 | s.enabled = audit_enabled; | |
1248 | s.failure = audit_failure; | |
1249 | /* NOTE: use pid_vnr() so the PID is relative to the current | |
1250 | * namespace */ | |
1251 | s.pid = auditd_pid_vnr(); | |
1252 | s.rate_limit = audit_rate_limit; | |
1253 | s.backlog_limit = audit_backlog_limit; | |
1254 | s.lost = atomic_read(&audit_lost); | |
1255 | s.backlog = skb_queue_len(&audit_queue); | |
1256 | s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL; | |
1257 | s.backlog_wait_time = audit_backlog_wait_time; | |
1258 | s.backlog_wait_time_actual = atomic_read(&audit_backlog_wait_time_actual); | |
1259 | audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s)); | |
1260 | break; | |
1261 | } | |
1262 | case AUDIT_SET: { | |
1263 | struct audit_status s; | |
1264 | memset(&s, 0, sizeof(s)); | |
1265 | /* guard against past and future API changes */ | |
1266 | memcpy(&s, data, min_t(size_t, sizeof(s), data_len)); | |
1267 | if (s.mask & AUDIT_STATUS_ENABLED) { | |
1268 | err = audit_set_enabled(s.enabled); | |
1269 | if (err < 0) | |
1270 | return err; | |
1271 | } | |
1272 | if (s.mask & AUDIT_STATUS_FAILURE) { | |
1273 | err = audit_set_failure(s.failure); | |
1274 | if (err < 0) | |
1275 | return err; | |
1276 | } | |
1277 | if (s.mask & AUDIT_STATUS_PID) { | |
1278 | /* NOTE: we are using the vnr PID functions below | |
1279 | * because the s.pid value is relative to the | |
1280 | * namespace of the caller; at present this | |
1281 | * doesn't matter much since you can really only | |
1282 | * run auditd from the initial pid namespace, but | |
1283 | * something to keep in mind if this changes */ | |
1284 | pid_t new_pid = s.pid; | |
1285 | pid_t auditd_pid; | |
1286 | struct pid *req_pid = task_tgid(current); | |
1287 | ||
1288 | /* Sanity check - PID values must match. Setting | |
1289 | * pid to 0 is how auditd ends auditing. */ | |
1290 | if (new_pid && (new_pid != pid_vnr(req_pid))) | |
1291 | return -EINVAL; | |
1292 | ||
1293 | /* test the auditd connection */ | |
1294 | audit_replace(req_pid); | |
1295 | ||
1296 | auditd_pid = auditd_pid_vnr(); | |
1297 | if (auditd_pid) { | |
1298 | /* replacing a healthy auditd is not allowed */ | |
1299 | if (new_pid) { | |
1300 | audit_log_config_change("audit_pid", | |
1301 | new_pid, auditd_pid, 0); | |
1302 | return -EEXIST; | |
1303 | } | |
1304 | /* only current auditd can unregister itself */ | |
1305 | if (pid_vnr(req_pid) != auditd_pid) { | |
1306 | audit_log_config_change("audit_pid", | |
1307 | new_pid, auditd_pid, 0); | |
1308 | return -EACCES; | |
1309 | } | |
1310 | } | |
1311 | ||
1312 | if (new_pid) { | |
1313 | /* register a new auditd connection */ | |
1314 | err = auditd_set(req_pid, | |
1315 | NETLINK_CB(skb).portid, | |
1316 | sock_net(NETLINK_CB(skb).sk)); | |
1317 | if (audit_enabled != AUDIT_OFF) | |
1318 | audit_log_config_change("audit_pid", | |
1319 | new_pid, | |
1320 | auditd_pid, | |
1321 | err ? 0 : 1); | |
1322 | if (err) | |
1323 | return err; | |
1324 | ||
1325 | /* try to process any backlog */ | |
1326 | wake_up_interruptible(&kauditd_wait); | |
1327 | } else { | |
1328 | if (audit_enabled != AUDIT_OFF) | |
1329 | audit_log_config_change("audit_pid", | |
1330 | new_pid, | |
1331 | auditd_pid, 1); | |
1332 | ||
1333 | /* unregister the auditd connection */ | |
1334 | auditd_reset(NULL); | |
1335 | } | |
1336 | } | |
1337 | if (s.mask & AUDIT_STATUS_RATE_LIMIT) { | |
1338 | err = audit_set_rate_limit(s.rate_limit); | |
1339 | if (err < 0) | |
1340 | return err; | |
1341 | } | |
1342 | if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) { | |
1343 | err = audit_set_backlog_limit(s.backlog_limit); | |
1344 | if (err < 0) | |
1345 | return err; | |
1346 | } | |
1347 | if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) { | |
1348 | if (sizeof(s) > (size_t)nlh->nlmsg_len) | |
1349 | return -EINVAL; | |
1350 | if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME) | |
1351 | return -EINVAL; | |
1352 | err = audit_set_backlog_wait_time(s.backlog_wait_time); | |
1353 | if (err < 0) | |
1354 | return err; | |
1355 | } | |
1356 | if (s.mask == AUDIT_STATUS_LOST) { | |
1357 | u32 lost = atomic_xchg(&audit_lost, 0); | |
1358 | ||
1359 | audit_log_config_change("lost", 0, lost, 1); | |
1360 | return lost; | |
1361 | } | |
1362 | if (s.mask == AUDIT_STATUS_BACKLOG_WAIT_TIME_ACTUAL) { | |
1363 | u32 actual = atomic_xchg(&audit_backlog_wait_time_actual, 0); | |
1364 | ||
1365 | audit_log_config_change("backlog_wait_time_actual", 0, actual, 1); | |
1366 | return actual; | |
1367 | } | |
1368 | break; | |
1369 | } | |
1370 | case AUDIT_GET_FEATURE: | |
1371 | err = audit_get_feature(skb); | |
1372 | if (err) | |
1373 | return err; | |
1374 | break; | |
1375 | case AUDIT_SET_FEATURE: | |
1376 | if (data_len < sizeof(struct audit_features)) | |
1377 | return -EINVAL; | |
1378 | err = audit_set_feature(data); | |
1379 | if (err) | |
1380 | return err; | |
1381 | break; | |
1382 | case AUDIT_USER: | |
1383 | case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG: | |
1384 | case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2: | |
1385 | if (!audit_enabled && msg_type != AUDIT_USER_AVC) | |
1386 | return 0; | |
1387 | /* exit early if there isn't at least one character to print */ | |
1388 | if (data_len < 2) | |
1389 | return -EINVAL; | |
1390 | ||
1391 | err = audit_filter(msg_type, AUDIT_FILTER_USER); | |
1392 | if (err == 1) { /* match or error */ | |
1393 | char *str = data; | |
1394 | ||
1395 | err = 0; | |
1396 | if (msg_type == AUDIT_USER_TTY) { | |
1397 | err = tty_audit_push(); | |
1398 | if (err) | |
1399 | break; | |
1400 | } | |
1401 | audit_log_user_recv_msg(&ab, msg_type); | |
1402 | if (msg_type != AUDIT_USER_TTY) { | |
1403 | /* ensure NULL termination */ | |
1404 | str[data_len - 1] = '\0'; | |
1405 | audit_log_format(ab, " msg='%.*s'", | |
1406 | AUDIT_MESSAGE_TEXT_MAX, | |
1407 | str); | |
1408 | } else { | |
1409 | audit_log_format(ab, " data="); | |
1410 | if (data_len > 0 && str[data_len - 1] == '\0') | |
1411 | data_len--; | |
1412 | audit_log_n_untrustedstring(ab, str, data_len); | |
1413 | } | |
1414 | audit_log_end(ab); | |
1415 | audit_log_lsm(NULL, false); | |
1416 | } | |
1417 | break; | |
1418 | case AUDIT_ADD_RULE: | |
1419 | case AUDIT_DEL_RULE: | |
1420 | if (data_len < sizeof(struct audit_rule_data)) | |
1421 | return -EINVAL; | |
1422 | if (audit_enabled == AUDIT_LOCKED) { | |
1423 | audit_log_common_recv_msg(audit_context(), &ab, | |
1424 | AUDIT_CONFIG_CHANGE); | |
1425 | audit_log_format(ab, " op=%s audit_enabled=%d res=0", | |
1426 | msg_type == AUDIT_ADD_RULE ? | |
1427 | "add_rule" : "remove_rule", | |
1428 | audit_enabled); | |
1429 | audit_log_end(ab); | |
1430 | return -EPERM; | |
1431 | } | |
1432 | err = audit_rule_change(msg_type, seq, data, data_len); | |
1433 | break; | |
1434 | case AUDIT_LIST_RULES: | |
1435 | err = audit_list_rules_send(skb, seq); | |
1436 | break; | |
1437 | case AUDIT_TRIM: | |
1438 | audit_trim_trees(); | |
1439 | audit_log_common_recv_msg(audit_context(), &ab, | |
1440 | AUDIT_CONFIG_CHANGE); | |
1441 | audit_log_format(ab, " op=trim res=1"); | |
1442 | audit_log_end(ab); | |
1443 | break; | |
1444 | case AUDIT_MAKE_EQUIV: { | |
1445 | void *bufp = data; | |
1446 | u32 sizes[2]; | |
1447 | size_t msglen = data_len; | |
1448 | char *old, *new; | |
1449 | ||
1450 | err = -EINVAL; | |
1451 | if (msglen < 2 * sizeof(u32)) | |
1452 | break; | |
1453 | memcpy(sizes, bufp, 2 * sizeof(u32)); | |
1454 | bufp += 2 * sizeof(u32); | |
1455 | msglen -= 2 * sizeof(u32); | |
1456 | old = audit_unpack_string(&bufp, &msglen, sizes[0]); | |
1457 | if (IS_ERR(old)) { | |
1458 | err = PTR_ERR(old); | |
1459 | break; | |
1460 | } | |
1461 | new = audit_unpack_string(&bufp, &msglen, sizes[1]); | |
1462 | if (IS_ERR(new)) { | |
1463 | err = PTR_ERR(new); | |
1464 | kfree(old); | |
1465 | break; | |
1466 | } | |
1467 | /* OK, here comes... */ | |
1468 | err = audit_tag_tree(old, new); | |
1469 | ||
1470 | audit_log_common_recv_msg(audit_context(), &ab, | |
1471 | AUDIT_CONFIG_CHANGE); | |
1472 | audit_log_format(ab, " op=make_equiv old="); | |
1473 | audit_log_untrustedstring(ab, old); | |
1474 | audit_log_format(ab, " new="); | |
1475 | audit_log_untrustedstring(ab, new); | |
1476 | audit_log_format(ab, " res=%d", !err); | |
1477 | audit_log_end(ab); | |
1478 | kfree(old); | |
1479 | kfree(new); | |
1480 | break; | |
1481 | } | |
1482 | case AUDIT_SIGNAL_INFO: { | |
1483 | struct lsmcontext context = { }; | |
1484 | int len = 0; | |
1485 | ||
1486 | if (lsmblob_is_set(&audit_sig_lsm)) { | |
1487 | err = security_secid_to_secctx(&audit_sig_lsm, | |
1488 | &context, LSMBLOB_FIRST); | |
1489 | if (err) | |
1490 | return err; | |
1491 | } | |
1492 | sig_data = kmalloc(sizeof(*sig_data) + context.len, GFP_KERNEL); | |
1493 | if (!sig_data) { | |
1494 | if (lsmblob_is_set(&audit_sig_lsm)) | |
1495 | security_release_secctx(&context); | |
1496 | return -ENOMEM; | |
1497 | } | |
1498 | sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid); | |
1499 | sig_data->pid = audit_sig_pid; | |
1500 | if (lsmblob_is_set(&audit_sig_lsm)) { | |
1501 | len = context.len; | |
1502 | memcpy(sig_data->ctx, context.context, len); | |
1503 | security_release_secctx(&context); | |
1504 | } | |
1505 | audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0, | |
1506 | sig_data, sizeof(*sig_data) + len); | |
1507 | kfree(sig_data); | |
1508 | break; | |
1509 | } | |
1510 | case AUDIT_TTY_GET: { | |
1511 | struct audit_tty_status s; | |
1512 | unsigned int t; | |
1513 | ||
1514 | t = READ_ONCE(current->signal->audit_tty); | |
1515 | s.enabled = t & AUDIT_TTY_ENABLE; | |
1516 | s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD); | |
1517 | ||
1518 | audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s)); | |
1519 | break; | |
1520 | } | |
1521 | case AUDIT_TTY_SET: { | |
1522 | struct audit_tty_status s, old; | |
1523 | struct audit_buffer *ab; | |
1524 | unsigned int t; | |
1525 | ||
1526 | memset(&s, 0, sizeof(s)); | |
1527 | /* guard against past and future API changes */ | |
1528 | memcpy(&s, data, min_t(size_t, sizeof(s), data_len)); | |
1529 | /* check if new data is valid */ | |
1530 | if ((s.enabled != 0 && s.enabled != 1) || | |
1531 | (s.log_passwd != 0 && s.log_passwd != 1)) | |
1532 | err = -EINVAL; | |
1533 | ||
1534 | if (err) | |
1535 | t = READ_ONCE(current->signal->audit_tty); | |
1536 | else { | |
1537 | t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD); | |
1538 | t = xchg(¤t->signal->audit_tty, t); | |
1539 | } | |
1540 | old.enabled = t & AUDIT_TTY_ENABLE; | |
1541 | old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD); | |
1542 | ||
1543 | audit_log_common_recv_msg(audit_context(), &ab, | |
1544 | AUDIT_CONFIG_CHANGE); | |
1545 | audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d" | |
1546 | " old-log_passwd=%d new-log_passwd=%d res=%d", | |
1547 | old.enabled, s.enabled, old.log_passwd, | |
1548 | s.log_passwd, !err); | |
1549 | audit_log_end(ab); | |
1550 | break; | |
1551 | } | |
1552 | default: | |
1553 | err = -EINVAL; | |
1554 | break; | |
1555 | } | |
1556 | ||
1557 | return err < 0 ? err : 0; | |
1558 | } | |
1559 | ||
1560 | /** | |
1561 | * audit_receive - receive messages from a netlink control socket | |
1562 | * @skb: the message buffer | |
1563 | * | |
1564 | * Parse the provided skb and deal with any messages that may be present, | |
1565 | * malformed skbs are discarded. | |
1566 | */ | |
1567 | static void audit_receive(struct sk_buff *skb) | |
1568 | { | |
1569 | struct nlmsghdr *nlh; | |
1570 | /* | |
1571 | * len MUST be signed for nlmsg_next to be able to dec it below 0 | |
1572 | * if the nlmsg_len was not aligned | |
1573 | */ | |
1574 | int len; | |
1575 | int err; | |
1576 | ||
1577 | nlh = nlmsg_hdr(skb); | |
1578 | len = skb->len; | |
1579 | ||
1580 | audit_ctl_lock(); | |
1581 | while (nlmsg_ok(nlh, len)) { | |
1582 | err = audit_receive_msg(skb, nlh); | |
1583 | /* if err or if this message says it wants a response */ | |
1584 | if (err || (nlh->nlmsg_flags & NLM_F_ACK)) | |
1585 | netlink_ack(skb, nlh, err, NULL); | |
1586 | ||
1587 | nlh = nlmsg_next(nlh, &len); | |
1588 | } | |
1589 | audit_ctl_unlock(); | |
1590 | ||
1591 | /* can't block with the ctrl lock, so penalize the sender now */ | |
1592 | if (audit_backlog_limit && | |
1593 | (skb_queue_len(&audit_queue) > audit_backlog_limit)) { | |
1594 | DECLARE_WAITQUEUE(wait, current); | |
1595 | ||
1596 | /* wake kauditd to try and flush the queue */ | |
1597 | wake_up_interruptible(&kauditd_wait); | |
1598 | ||
1599 | add_wait_queue_exclusive(&audit_backlog_wait, &wait); | |
1600 | set_current_state(TASK_UNINTERRUPTIBLE); | |
1601 | schedule_timeout(audit_backlog_wait_time); | |
1602 | remove_wait_queue(&audit_backlog_wait, &wait); | |
1603 | } | |
1604 | } | |
1605 | ||
1606 | /* Log information about who is connecting to the audit multicast socket */ | |
1607 | static void audit_log_multicast(int group, const char *op, int err) | |
1608 | { | |
1609 | const struct cred *cred; | |
1610 | struct tty_struct *tty; | |
1611 | char comm[sizeof(current->comm)]; | |
1612 | struct audit_buffer *ab; | |
1613 | ||
1614 | if (!audit_enabled) | |
1615 | return; | |
1616 | ||
1617 | ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_EVENT_LISTENER); | |
1618 | if (!ab) | |
1619 | return; | |
1620 | ||
1621 | cred = current_cred(); | |
1622 | tty = audit_get_tty(); | |
1623 | audit_log_format(ab, "pid=%u uid=%u auid=%u tty=%s ses=%u", | |
1624 | task_pid_nr(current), | |
1625 | from_kuid(&init_user_ns, cred->uid), | |
1626 | from_kuid(&init_user_ns, audit_get_loginuid(current)), | |
1627 | tty ? tty_name(tty) : "(none)", | |
1628 | audit_get_sessionid(current)); | |
1629 | audit_put_tty(tty); | |
1630 | audit_log_task_context(ab, NULL); /* subj= */ | |
1631 | audit_log_format(ab, " comm="); | |
1632 | audit_log_untrustedstring(ab, get_task_comm(comm, current)); | |
1633 | audit_log_d_path_exe(ab, current->mm); /* exe= */ | |
1634 | audit_log_format(ab, " nl-mcgrp=%d op=%s res=%d", group, op, !err); | |
1635 | audit_log_end(ab); | |
1636 | } | |
1637 | ||
1638 | /* Run custom bind function on netlink socket group connect or bind requests. */ | |
1639 | static int audit_multicast_bind(struct net *net, int group) | |
1640 | { | |
1641 | int err = 0; | |
1642 | ||
1643 | if (!capable(CAP_AUDIT_READ)) | |
1644 | err = -EPERM; | |
1645 | audit_log_multicast(group, "connect", err); | |
1646 | return err; | |
1647 | } | |
1648 | ||
1649 | static void audit_multicast_unbind(struct net *net, int group) | |
1650 | { | |
1651 | audit_log_multicast(group, "disconnect", 0); | |
1652 | } | |
1653 | ||
1654 | static int __net_init audit_net_init(struct net *net) | |
1655 | { | |
1656 | struct netlink_kernel_cfg cfg = { | |
1657 | .input = audit_receive, | |
1658 | .bind = audit_multicast_bind, | |
1659 | .unbind = audit_multicast_unbind, | |
1660 | .flags = NL_CFG_F_NONROOT_RECV, | |
1661 | .groups = AUDIT_NLGRP_MAX, | |
1662 | }; | |
1663 | ||
1664 | struct audit_net *aunet = net_generic(net, audit_net_id); | |
1665 | ||
1666 | aunet->sk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg); | |
1667 | if (aunet->sk == NULL) { | |
1668 | audit_panic("cannot initialize netlink socket in namespace"); | |
1669 | return -ENOMEM; | |
1670 | } | |
1671 | /* limit the timeout in case auditd is blocked/stopped */ | |
1672 | aunet->sk->sk_sndtimeo = HZ / 10; | |
1673 | ||
1674 | return 0; | |
1675 | } | |
1676 | ||
1677 | static void __net_exit audit_net_exit(struct net *net) | |
1678 | { | |
1679 | struct audit_net *aunet = net_generic(net, audit_net_id); | |
1680 | ||
1681 | /* NOTE: you would think that we would want to check the auditd | |
1682 | * connection and potentially reset it here if it lives in this | |
1683 | * namespace, but since the auditd connection tracking struct holds a | |
1684 | * reference to this namespace (see auditd_set()) we are only ever | |
1685 | * going to get here after that connection has been released */ | |
1686 | ||
1687 | netlink_kernel_release(aunet->sk); | |
1688 | } | |
1689 | ||
1690 | static struct pernet_operations audit_net_ops __net_initdata = { | |
1691 | .init = audit_net_init, | |
1692 | .exit = audit_net_exit, | |
1693 | .id = &audit_net_id, | |
1694 | .size = sizeof(struct audit_net), | |
1695 | }; | |
1696 | ||
1697 | /* Initialize audit support at boot time. */ | |
1698 | static int __init audit_init(void) | |
1699 | { | |
1700 | int i; | |
1701 | ||
1702 | if (audit_initialized == AUDIT_DISABLED) | |
1703 | return 0; | |
1704 | ||
1705 | audit_buffer_cache = kmem_cache_create("audit_buffer", | |
1706 | sizeof(struct audit_buffer), | |
1707 | 0, SLAB_PANIC, NULL); | |
1708 | ||
1709 | skb_queue_head_init(&audit_queue); | |
1710 | skb_queue_head_init(&audit_retry_queue); | |
1711 | skb_queue_head_init(&audit_hold_queue); | |
1712 | ||
1713 | for (i = 0; i < AUDIT_INODE_BUCKETS; i++) | |
1714 | INIT_LIST_HEAD(&audit_inode_hash[i]); | |
1715 | ||
1716 | mutex_init(&audit_cmd_mutex.lock); | |
1717 | audit_cmd_mutex.owner = NULL; | |
1718 | ||
1719 | pr_info("initializing netlink subsys (%s)\n", | |
1720 | audit_default ? "enabled" : "disabled"); | |
1721 | register_pernet_subsys(&audit_net_ops); | |
1722 | ||
1723 | audit_initialized = AUDIT_INITIALIZED; | |
1724 | ||
1725 | kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd"); | |
1726 | if (IS_ERR(kauditd_task)) { | |
1727 | int err = PTR_ERR(kauditd_task); | |
1728 | panic("audit: failed to start the kauditd thread (%d)\n", err); | |
1729 | } | |
1730 | ||
1731 | audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, | |
1732 | "state=initialized audit_enabled=%u res=1", | |
1733 | audit_enabled); | |
1734 | ||
1735 | return 0; | |
1736 | } | |
1737 | postcore_initcall(audit_init); | |
1738 | ||
1739 | /* | |
1740 | * Process kernel command-line parameter at boot time. | |
1741 | * audit={0|off} or audit={1|on}. | |
1742 | */ | |
1743 | static int __init audit_enable(char *str) | |
1744 | { | |
1745 | if (!strcasecmp(str, "off") || !strcmp(str, "0")) | |
1746 | audit_default = AUDIT_OFF; | |
1747 | else if (!strcasecmp(str, "on") || !strcmp(str, "1")) | |
1748 | audit_default = AUDIT_ON; | |
1749 | else { | |
1750 | pr_err("audit: invalid 'audit' parameter value (%s)\n", str); | |
1751 | audit_default = AUDIT_ON; | |
1752 | } | |
1753 | ||
1754 | if (audit_default == AUDIT_OFF) | |
1755 | audit_initialized = AUDIT_DISABLED; | |
1756 | if (audit_set_enabled(audit_default)) | |
1757 | pr_err("audit: error setting audit state (%d)\n", | |
1758 | audit_default); | |
1759 | ||
1760 | pr_info("%s\n", audit_default ? | |
1761 | "enabled (after initialization)" : "disabled (until reboot)"); | |
1762 | ||
1763 | return 1; | |
1764 | } | |
1765 | __setup("audit=", audit_enable); | |
1766 | ||
1767 | /* Process kernel command-line parameter at boot time. | |
1768 | * audit_backlog_limit=<n> */ | |
1769 | static int __init audit_backlog_limit_set(char *str) | |
1770 | { | |
1771 | u32 audit_backlog_limit_arg; | |
1772 | ||
1773 | pr_info("audit_backlog_limit: "); | |
1774 | if (kstrtouint(str, 0, &audit_backlog_limit_arg)) { | |
1775 | pr_cont("using default of %u, unable to parse %s\n", | |
1776 | audit_backlog_limit, str); | |
1777 | return 1; | |
1778 | } | |
1779 | ||
1780 | audit_backlog_limit = audit_backlog_limit_arg; | |
1781 | pr_cont("%d\n", audit_backlog_limit); | |
1782 | ||
1783 | return 1; | |
1784 | } | |
1785 | __setup("audit_backlog_limit=", audit_backlog_limit_set); | |
1786 | ||
1787 | static void audit_buffer_free(struct audit_buffer *ab) | |
1788 | { | |
1789 | if (!ab) | |
1790 | return; | |
1791 | ||
1792 | kfree_skb(ab->skb); | |
1793 | kmem_cache_free(audit_buffer_cache, ab); | |
1794 | } | |
1795 | ||
1796 | static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx, | |
1797 | gfp_t gfp_mask, int type) | |
1798 | { | |
1799 | struct audit_buffer *ab; | |
1800 | ||
1801 | ab = kmem_cache_alloc(audit_buffer_cache, gfp_mask); | |
1802 | if (!ab) | |
1803 | return NULL; | |
1804 | ||
1805 | ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask); | |
1806 | if (!ab->skb) | |
1807 | goto err; | |
1808 | if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0)) | |
1809 | goto err; | |
1810 | ||
1811 | ab->ctx = ctx; | |
1812 | ab->gfp_mask = gfp_mask; | |
1813 | ||
1814 | return ab; | |
1815 | ||
1816 | err: | |
1817 | audit_buffer_free(ab); | |
1818 | return NULL; | |
1819 | } | |
1820 | ||
1821 | /** | |
1822 | * audit_serial - compute a serial number for the audit record | |
1823 | * | |
1824 | * Compute a serial number for the audit record. Audit records are | |
1825 | * written to user-space as soon as they are generated, so a complete | |
1826 | * audit record may be written in several pieces. The timestamp of the | |
1827 | * record and this serial number are used by the user-space tools to | |
1828 | * determine which pieces belong to the same audit record. The | |
1829 | * (timestamp,serial) tuple is unique for each syscall and is live from | |
1830 | * syscall entry to syscall exit. | |
1831 | * | |
1832 | * NOTE: Another possibility is to store the formatted records off the | |
1833 | * audit context (for those records that have a context), and emit them | |
1834 | * all at syscall exit. However, this could delay the reporting of | |
1835 | * significant errors until syscall exit (or never, if the system | |
1836 | * halts). | |
1837 | */ | |
1838 | unsigned int audit_serial(void) | |
1839 | { | |
1840 | static atomic_t serial = ATOMIC_INIT(0); | |
1841 | ||
1842 | return atomic_inc_return(&serial); | |
1843 | } | |
1844 | ||
1845 | static inline void audit_get_stamp(struct audit_context *ctx, | |
1846 | struct timespec64 *t, unsigned int *serial) | |
1847 | { | |
1848 | if (!ctx || !auditsc_get_stamp(ctx, t, serial)) { | |
1849 | ktime_get_coarse_real_ts64(t); | |
1850 | *serial = audit_serial(); | |
1851 | } | |
1852 | } | |
1853 | ||
1854 | /** | |
1855 | * audit_log_start - obtain an audit buffer | |
1856 | * @ctx: audit_context (may be NULL) | |
1857 | * @gfp_mask: type of allocation | |
1858 | * @type: audit message type | |
1859 | * | |
1860 | * Returns audit_buffer pointer on success or NULL on error. | |
1861 | * | |
1862 | * Obtain an audit buffer. This routine does locking to obtain the | |
1863 | * audit buffer, but then no locking is required for calls to | |
1864 | * audit_log_*format. If the task (ctx) is a task that is currently in a | |
1865 | * syscall, then the syscall is marked as auditable and an audit record | |
1866 | * will be written at syscall exit. If there is no associated task, then | |
1867 | * task context (ctx) should be NULL. | |
1868 | */ | |
1869 | struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, | |
1870 | int type) | |
1871 | { | |
1872 | struct audit_buffer *ab; | |
1873 | struct timespec64 t; | |
1874 | unsigned int serial; | |
1875 | ||
1876 | if (audit_initialized != AUDIT_INITIALIZED) | |
1877 | return NULL; | |
1878 | ||
1879 | if (unlikely(!audit_filter(type, AUDIT_FILTER_EXCLUDE))) | |
1880 | return NULL; | |
1881 | ||
1882 | /* NOTE: don't ever fail/sleep on these two conditions: | |
1883 | * 1. auditd generated record - since we need auditd to drain the | |
1884 | * queue; also, when we are checking for auditd, compare PIDs using | |
1885 | * task_tgid_vnr() since auditd_pid is set in audit_receive_msg() | |
1886 | * using a PID anchored in the caller's namespace | |
1887 | * 2. generator holding the audit_cmd_mutex - we don't want to block | |
1888 | * while holding the mutex, although we do penalize the sender | |
1889 | * later in audit_receive() when it is safe to block | |
1890 | */ | |
1891 | if (!(auditd_test_task(current) || audit_ctl_owner_current())) { | |
1892 | long stime = audit_backlog_wait_time; | |
1893 | ||
1894 | while (audit_backlog_limit && | |
1895 | (skb_queue_len(&audit_queue) > audit_backlog_limit)) { | |
1896 | /* wake kauditd to try and flush the queue */ | |
1897 | wake_up_interruptible(&kauditd_wait); | |
1898 | ||
1899 | /* sleep if we are allowed and we haven't exhausted our | |
1900 | * backlog wait limit */ | |
1901 | if (gfpflags_allow_blocking(gfp_mask) && (stime > 0)) { | |
1902 | long rtime = stime; | |
1903 | ||
1904 | DECLARE_WAITQUEUE(wait, current); | |
1905 | ||
1906 | add_wait_queue_exclusive(&audit_backlog_wait, | |
1907 | &wait); | |
1908 | set_current_state(TASK_UNINTERRUPTIBLE); | |
1909 | stime = schedule_timeout(rtime); | |
1910 | atomic_add(rtime - stime, &audit_backlog_wait_time_actual); | |
1911 | remove_wait_queue(&audit_backlog_wait, &wait); | |
1912 | } else { | |
1913 | if (audit_rate_check() && printk_ratelimit()) | |
1914 | pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n", | |
1915 | skb_queue_len(&audit_queue), | |
1916 | audit_backlog_limit); | |
1917 | audit_log_lost("backlog limit exceeded"); | |
1918 | return NULL; | |
1919 | } | |
1920 | } | |
1921 | } | |
1922 | ||
1923 | ab = audit_buffer_alloc(ctx, gfp_mask, type); | |
1924 | if (!ab) { | |
1925 | audit_log_lost("out of memory in audit_log_start"); | |
1926 | return NULL; | |
1927 | } | |
1928 | ||
1929 | audit_get_stamp(ab->ctx, &t, &serial); | |
1930 | /* cancel dummy context to enable supporting records */ | |
1931 | if (ctx) | |
1932 | ctx->dummy = 0; | |
1933 | if (type == AUDIT_MAC_TASK_CONTEXTS && ab->ctx && | |
1934 | ab->ctx->serial == 0) { | |
1935 | audit_stamp_context(ab->ctx); | |
1936 | audit_get_stamp(ab->ctx, &t, &serial); | |
1937 | } | |
1938 | audit_log_format(ab, "audit(%llu.%03lu:%u): ", | |
1939 | (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial); | |
1940 | ||
1941 | return ab; | |
1942 | } | |
1943 | ||
1944 | /** | |
1945 | * audit_expand - expand skb in the audit buffer | |
1946 | * @ab: audit_buffer | |
1947 | * @extra: space to add at tail of the skb | |
1948 | * | |
1949 | * Returns 0 (no space) on failed expansion, or available space if | |
1950 | * successful. | |
1951 | */ | |
1952 | static inline int audit_expand(struct audit_buffer *ab, int extra) | |
1953 | { | |
1954 | struct sk_buff *skb = ab->skb; | |
1955 | int oldtail = skb_tailroom(skb); | |
1956 | int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask); | |
1957 | int newtail = skb_tailroom(skb); | |
1958 | ||
1959 | if (ret < 0) { | |
1960 | audit_log_lost("out of memory in audit_expand"); | |
1961 | return 0; | |
1962 | } | |
1963 | ||
1964 | skb->truesize += newtail - oldtail; | |
1965 | return newtail; | |
1966 | } | |
1967 | ||
1968 | /* | |
1969 | * Format an audit message into the audit buffer. If there isn't enough | |
1970 | * room in the audit buffer, more room will be allocated and vsnprint | |
1971 | * will be called a second time. Currently, we assume that a printk | |
1972 | * can't format message larger than 1024 bytes, so we don't either. | |
1973 | */ | |
1974 | static void audit_log_vformat(struct audit_buffer *ab, const char *fmt, | |
1975 | va_list args) | |
1976 | { | |
1977 | int len, avail; | |
1978 | struct sk_buff *skb; | |
1979 | va_list args2; | |
1980 | ||
1981 | if (!ab) | |
1982 | return; | |
1983 | ||
1984 | BUG_ON(!ab->skb); | |
1985 | skb = ab->skb; | |
1986 | avail = skb_tailroom(skb); | |
1987 | if (avail == 0) { | |
1988 | avail = audit_expand(ab, AUDIT_BUFSIZ); | |
1989 | if (!avail) | |
1990 | goto out; | |
1991 | } | |
1992 | va_copy(args2, args); | |
1993 | len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args); | |
1994 | if (len >= avail) { | |
1995 | /* The printk buffer is 1024 bytes long, so if we get | |
1996 | * here and AUDIT_BUFSIZ is at least 1024, then we can | |
1997 | * log everything that printk could have logged. */ | |
1998 | avail = audit_expand(ab, | |
1999 | max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail)); | |
2000 | if (!avail) | |
2001 | goto out_va_end; | |
2002 | len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2); | |
2003 | } | |
2004 | if (len > 0) | |
2005 | skb_put(skb, len); | |
2006 | out_va_end: | |
2007 | va_end(args2); | |
2008 | out: | |
2009 | return; | |
2010 | } | |
2011 | ||
2012 | /** | |
2013 | * audit_log_format - format a message into the audit buffer. | |
2014 | * @ab: audit_buffer | |
2015 | * @fmt: format string | |
2016 | * @...: optional parameters matching @fmt string | |
2017 | * | |
2018 | * All the work is done in audit_log_vformat. | |
2019 | */ | |
2020 | void audit_log_format(struct audit_buffer *ab, const char *fmt, ...) | |
2021 | { | |
2022 | va_list args; | |
2023 | ||
2024 | if (!ab) | |
2025 | return; | |
2026 | va_start(args, fmt); | |
2027 | audit_log_vformat(ab, fmt, args); | |
2028 | va_end(args); | |
2029 | } | |
2030 | ||
2031 | /** | |
2032 | * audit_log_n_hex - convert a buffer to hex and append it to the audit skb | |
2033 | * @ab: the audit_buffer | |
2034 | * @buf: buffer to convert to hex | |
2035 | * @len: length of @buf to be converted | |
2036 | * | |
2037 | * No return value; failure to expand is silently ignored. | |
2038 | * | |
2039 | * This function will take the passed buf and convert it into a string of | |
2040 | * ascii hex digits. The new string is placed onto the skb. | |
2041 | */ | |
2042 | void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf, | |
2043 | size_t len) | |
2044 | { | |
2045 | int i, avail, new_len; | |
2046 | unsigned char *ptr; | |
2047 | struct sk_buff *skb; | |
2048 | ||
2049 | if (!ab) | |
2050 | return; | |
2051 | ||
2052 | BUG_ON(!ab->skb); | |
2053 | skb = ab->skb; | |
2054 | avail = skb_tailroom(skb); | |
2055 | new_len = len<<1; | |
2056 | if (new_len >= avail) { | |
2057 | /* Round the buffer request up to the next multiple */ | |
2058 | new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1); | |
2059 | avail = audit_expand(ab, new_len); | |
2060 | if (!avail) | |
2061 | return; | |
2062 | } | |
2063 | ||
2064 | ptr = skb_tail_pointer(skb); | |
2065 | for (i = 0; i < len; i++) | |
2066 | ptr = hex_byte_pack_upper(ptr, buf[i]); | |
2067 | *ptr = 0; | |
2068 | skb_put(skb, len << 1); /* new string is twice the old string */ | |
2069 | } | |
2070 | ||
2071 | /* | |
2072 | * Format a string of no more than slen characters into the audit buffer, | |
2073 | * enclosed in quote marks. | |
2074 | */ | |
2075 | void audit_log_n_string(struct audit_buffer *ab, const char *string, | |
2076 | size_t slen) | |
2077 | { | |
2078 | int avail, new_len; | |
2079 | unsigned char *ptr; | |
2080 | struct sk_buff *skb; | |
2081 | ||
2082 | if (!ab) | |
2083 | return; | |
2084 | ||
2085 | BUG_ON(!ab->skb); | |
2086 | skb = ab->skb; | |
2087 | avail = skb_tailroom(skb); | |
2088 | new_len = slen + 3; /* enclosing quotes + null terminator */ | |
2089 | if (new_len > avail) { | |
2090 | avail = audit_expand(ab, new_len); | |
2091 | if (!avail) | |
2092 | return; | |
2093 | } | |
2094 | ptr = skb_tail_pointer(skb); | |
2095 | *ptr++ = '"'; | |
2096 | memcpy(ptr, string, slen); | |
2097 | ptr += slen; | |
2098 | *ptr++ = '"'; | |
2099 | *ptr = 0; | |
2100 | skb_put(skb, slen + 2); /* don't include null terminator */ | |
2101 | } | |
2102 | ||
2103 | /** | |
2104 | * audit_string_contains_control - does a string need to be logged in hex | |
2105 | * @string: string to be checked | |
2106 | * @len: max length of the string to check | |
2107 | */ | |
2108 | bool audit_string_contains_control(const char *string, size_t len) | |
2109 | { | |
2110 | const unsigned char *p; | |
2111 | for (p = string; p < (const unsigned char *)string + len; p++) { | |
2112 | if (*p == '"' || *p < 0x21 || *p > 0x7e) | |
2113 | return true; | |
2114 | } | |
2115 | return false; | |
2116 | } | |
2117 | ||
2118 | /** | |
2119 | * audit_log_n_untrustedstring - log a string that may contain random characters | |
2120 | * @ab: audit_buffer | |
2121 | * @len: length of string (not including trailing null) | |
2122 | * @string: string to be logged | |
2123 | * | |
2124 | * This code will escape a string that is passed to it if the string | |
2125 | * contains a control character, unprintable character, double quote mark, | |
2126 | * or a space. Unescaped strings will start and end with a double quote mark. | |
2127 | * Strings that are escaped are printed in hex (2 digits per char). | |
2128 | * | |
2129 | * The caller specifies the number of characters in the string to log, which may | |
2130 | * or may not be the entire string. | |
2131 | */ | |
2132 | void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string, | |
2133 | size_t len) | |
2134 | { | |
2135 | if (audit_string_contains_control(string, len)) | |
2136 | audit_log_n_hex(ab, string, len); | |
2137 | else | |
2138 | audit_log_n_string(ab, string, len); | |
2139 | } | |
2140 | ||
2141 | /** | |
2142 | * audit_log_untrustedstring - log a string that may contain random characters | |
2143 | * @ab: audit_buffer | |
2144 | * @string: string to be logged | |
2145 | * | |
2146 | * Same as audit_log_n_untrustedstring(), except that strlen is used to | |
2147 | * determine string length. | |
2148 | */ | |
2149 | void audit_log_untrustedstring(struct audit_buffer *ab, const char *string) | |
2150 | { | |
2151 | audit_log_n_untrustedstring(ab, string, strlen(string)); | |
2152 | } | |
2153 | ||
2154 | /* This is a helper-function to print the escaped d_path */ | |
2155 | void audit_log_d_path(struct audit_buffer *ab, const char *prefix, | |
2156 | const struct path *path) | |
2157 | { | |
2158 | char *p, *pathname; | |
2159 | ||
2160 | if (prefix) | |
2161 | audit_log_format(ab, "%s", prefix); | |
2162 | ||
2163 | /* We will allow 11 spaces for ' (deleted)' to be appended */ | |
2164 | pathname = kmalloc(PATH_MAX+11, ab->gfp_mask); | |
2165 | if (!pathname) { | |
2166 | audit_log_format(ab, "\"<no_memory>\""); | |
2167 | return; | |
2168 | } | |
2169 | p = d_path(path, pathname, PATH_MAX+11); | |
2170 | if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */ | |
2171 | /* FIXME: can we save some information here? */ | |
2172 | audit_log_format(ab, "\"<too_long>\""); | |
2173 | } else | |
2174 | audit_log_untrustedstring(ab, p); | |
2175 | kfree(pathname); | |
2176 | } | |
2177 | ||
2178 | void audit_log_session_info(struct audit_buffer *ab) | |
2179 | { | |
2180 | unsigned int sessionid = audit_get_sessionid(current); | |
2181 | uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current)); | |
2182 | ||
2183 | audit_log_format(ab, "auid=%u ses=%u", auid, sessionid); | |
2184 | } | |
2185 | ||
2186 | void audit_log_key(struct audit_buffer *ab, char *key) | |
2187 | { | |
2188 | audit_log_format(ab, " key="); | |
2189 | if (key) | |
2190 | audit_log_untrustedstring(ab, key); | |
2191 | else | |
2192 | audit_log_format(ab, "(null)"); | |
2193 | } | |
2194 | ||
2195 | int audit_log_task_context(struct audit_buffer *ab, struct lsmblob *blob) | |
2196 | { | |
2197 | int i; | |
2198 | int error; | |
2199 | struct lsmblob localblob; | |
2200 | struct lsmcontext lsmdata; | |
2201 | ||
2202 | /* | |
2203 | * If there is more than one security module that has a | |
2204 | * subject "context" it's necessary to put the subject data | |
2205 | * into a separate record to maintain compatibility. | |
2206 | */ | |
2207 | if (lsm_multiple_contexts()) { | |
2208 | audit_log_format(ab, " subj=?"); | |
2209 | return 0; | |
2210 | } | |
2211 | ||
2212 | if (blob == NULL) { | |
2213 | security_task_getsecid_subj(current, &localblob); | |
2214 | if (!lsmblob_is_set(&localblob)) { | |
2215 | audit_log_format(ab, " subj=?"); | |
2216 | return 0; | |
2217 | } | |
2218 | blob = &localblob; | |
2219 | } | |
2220 | ||
2221 | for (i = 0; i < LSMBLOB_ENTRIES; i++) { | |
2222 | if (blob->secid[i] == 0) | |
2223 | continue; | |
2224 | error = security_secid_to_secctx(blob, &lsmdata, i); | |
2225 | if (error && error != -EINVAL) { | |
2226 | audit_panic("error in audit_log_task_context"); | |
2227 | return error; | |
2228 | } | |
2229 | ||
2230 | audit_log_format(ab, " subj=%s", lsmdata.context); | |
2231 | security_release_secctx(&lsmdata); | |
2232 | break; | |
2233 | } | |
2234 | ||
2235 | return 0; | |
2236 | } | |
2237 | EXPORT_SYMBOL(audit_log_task_context); | |
2238 | ||
2239 | int audit_log_object_context(struct audit_buffer *ab, | |
2240 | struct lsmblob *blob) | |
2241 | { | |
2242 | int i; | |
2243 | int error; | |
2244 | bool sep = false; | |
2245 | struct lsmcontext lsmdata; | |
2246 | struct audit_buffer *lsmab = NULL; | |
2247 | struct audit_context *context = NULL; | |
2248 | ||
2249 | /* | |
2250 | * If there is more than one security module that has a | |
2251 | * object "context" it's necessary to put the object data | |
2252 | * into a separate record to maintain compatibility. | |
2253 | */ | |
2254 | if (lsm_multiple_contexts()) { | |
2255 | audit_log_format(ab, " obj=?"); | |
2256 | context = ab->ctx; | |
2257 | if (context) | |
2258 | lsmab = audit_log_start(context, GFP_KERNEL, | |
2259 | AUDIT_MAC_OBJ_CONTEXTS); | |
2260 | } | |
2261 | ||
2262 | for (i = 0; i < LSMBLOB_ENTRIES; i++) { | |
2263 | if (blob->secid[i] == 0) | |
2264 | continue; | |
2265 | error = security_secid_to_secctx(blob, &lsmdata, i); | |
2266 | if (error && error != -EINVAL) { | |
2267 | audit_panic("error in audit_log_object_context"); | |
2268 | return error; | |
2269 | } | |
2270 | ||
2271 | if (context) { | |
2272 | audit_log_format(lsmab, "%sobj_%s=%s", | |
2273 | sep ? " " : "", | |
2274 | security_lsm_slot_name(i), | |
2275 | lsmdata.context); | |
2276 | sep = true; | |
2277 | } else | |
2278 | audit_log_format(ab, " obj=%s", lsmdata.context); | |
2279 | ||
2280 | security_release_secctx(&lsmdata); | |
2281 | if (!context) | |
2282 | break; | |
2283 | } | |
2284 | ||
2285 | if (context) | |
2286 | audit_log_end(lsmab); | |
2287 | ||
2288 | return 0; | |
2289 | } | |
2290 | EXPORT_SYMBOL(audit_log_object_context); | |
2291 | ||
2292 | void audit_log_d_path_exe(struct audit_buffer *ab, | |
2293 | struct mm_struct *mm) | |
2294 | { | |
2295 | struct file *exe_file; | |
2296 | ||
2297 | if (!mm) | |
2298 | goto out_null; | |
2299 | ||
2300 | exe_file = get_mm_exe_file(mm); | |
2301 | if (!exe_file) | |
2302 | goto out_null; | |
2303 | ||
2304 | audit_log_d_path(ab, " exe=", &exe_file->f_path); | |
2305 | fput(exe_file); | |
2306 | return; | |
2307 | out_null: | |
2308 | audit_log_format(ab, " exe=(null)"); | |
2309 | } | |
2310 | ||
2311 | struct tty_struct *audit_get_tty(void) | |
2312 | { | |
2313 | struct tty_struct *tty = NULL; | |
2314 | unsigned long flags; | |
2315 | ||
2316 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
2317 | if (current->signal) | |
2318 | tty = tty_kref_get(current->signal->tty); | |
2319 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
2320 | return tty; | |
2321 | } | |
2322 | ||
2323 | void audit_put_tty(struct tty_struct *tty) | |
2324 | { | |
2325 | tty_kref_put(tty); | |
2326 | } | |
2327 | ||
2328 | void audit_log_task_info(struct audit_buffer *ab) | |
2329 | { | |
2330 | const struct cred *cred; | |
2331 | char comm[sizeof(current->comm)]; | |
2332 | struct tty_struct *tty; | |
2333 | ||
2334 | if (!ab) | |
2335 | return; | |
2336 | ||
2337 | cred = current_cred(); | |
2338 | tty = audit_get_tty(); | |
2339 | audit_log_format(ab, | |
2340 | " ppid=%d pid=%d auid=%u uid=%u gid=%u" | |
2341 | " euid=%u suid=%u fsuid=%u" | |
2342 | " egid=%u sgid=%u fsgid=%u tty=%s ses=%u", | |
2343 | task_ppid_nr(current), | |
2344 | task_tgid_nr(current), | |
2345 | from_kuid(&init_user_ns, audit_get_loginuid(current)), | |
2346 | from_kuid(&init_user_ns, cred->uid), | |
2347 | from_kgid(&init_user_ns, cred->gid), | |
2348 | from_kuid(&init_user_ns, cred->euid), | |
2349 | from_kuid(&init_user_ns, cred->suid), | |
2350 | from_kuid(&init_user_ns, cred->fsuid), | |
2351 | from_kgid(&init_user_ns, cred->egid), | |
2352 | from_kgid(&init_user_ns, cred->sgid), | |
2353 | from_kgid(&init_user_ns, cred->fsgid), | |
2354 | tty ? tty_name(tty) : "(none)", | |
2355 | audit_get_sessionid(current)); | |
2356 | audit_put_tty(tty); | |
2357 | audit_log_format(ab, " comm="); | |
2358 | audit_log_untrustedstring(ab, get_task_comm(comm, current)); | |
2359 | audit_log_d_path_exe(ab, current->mm); | |
2360 | audit_log_task_context(ab, NULL); | |
2361 | } | |
2362 | EXPORT_SYMBOL(audit_log_task_info); | |
2363 | ||
2364 | /** | |
2365 | * audit_log_path_denied - report a path restriction denial | |
2366 | * @type: audit message type (AUDIT_ANOM_LINK, AUDIT_ANOM_CREAT, etc) | |
2367 | * @operation: specific operation name | |
2368 | */ | |
2369 | void audit_log_path_denied(int type, const char *operation) | |
2370 | { | |
2371 | struct audit_buffer *ab; | |
2372 | ||
2373 | if (!audit_enabled || audit_dummy_context()) | |
2374 | return; | |
2375 | ||
2376 | /* Generate log with subject, operation, outcome. */ | |
2377 | ab = audit_log_start(audit_context(), GFP_KERNEL, type); | |
2378 | if (!ab) | |
2379 | return; | |
2380 | audit_log_format(ab, "op=%s", operation); | |
2381 | audit_log_task_info(ab); | |
2382 | audit_log_format(ab, " res=0"); | |
2383 | audit_log_end(ab); | |
2384 | } | |
2385 | ||
2386 | /* global counter which is incremented every time something logs in */ | |
2387 | static atomic_t session_id = ATOMIC_INIT(0); | |
2388 | ||
2389 | static int audit_set_loginuid_perm(kuid_t loginuid) | |
2390 | { | |
2391 | /* if we are unset, we don't need privs */ | |
2392 | if (!audit_loginuid_set(current)) | |
2393 | return 0; | |
2394 | /* if AUDIT_FEATURE_LOGINUID_IMMUTABLE means never ever allow a change*/ | |
2395 | if (is_audit_feature_set(AUDIT_FEATURE_LOGINUID_IMMUTABLE)) | |
2396 | return -EPERM; | |
2397 | /* it is set, you need permission */ | |
2398 | if (!capable(CAP_AUDIT_CONTROL)) | |
2399 | return -EPERM; | |
2400 | /* reject if this is not an unset and we don't allow that */ | |
2401 | if (is_audit_feature_set(AUDIT_FEATURE_ONLY_UNSET_LOGINUID) | |
2402 | && uid_valid(loginuid)) | |
2403 | return -EPERM; | |
2404 | return 0; | |
2405 | } | |
2406 | ||
2407 | static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid, | |
2408 | unsigned int oldsessionid, | |
2409 | unsigned int sessionid, int rc) | |
2410 | { | |
2411 | struct audit_buffer *ab; | |
2412 | uid_t uid, oldloginuid, loginuid; | |
2413 | struct tty_struct *tty; | |
2414 | ||
2415 | if (!audit_enabled) | |
2416 | return; | |
2417 | ||
2418 | audit_stamp_context(audit_context()); | |
2419 | ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_LOGIN); | |
2420 | if (!ab) | |
2421 | return; | |
2422 | ||
2423 | uid = from_kuid(&init_user_ns, task_uid(current)); | |
2424 | oldloginuid = from_kuid(&init_user_ns, koldloginuid); | |
2425 | loginuid = from_kuid(&init_user_ns, kloginuid); | |
2426 | tty = audit_get_tty(); | |
2427 | ||
2428 | audit_log_format(ab, "pid=%d uid=%u", task_tgid_nr(current), uid); | |
2429 | audit_log_task_context(ab, NULL); | |
2430 | audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d", | |
2431 | oldloginuid, loginuid, tty ? tty_name(tty) : "(none)", | |
2432 | oldsessionid, sessionid, !rc); | |
2433 | audit_put_tty(tty); | |
2434 | audit_log_lsm(NULL, true); | |
2435 | audit_log_end(ab); | |
2436 | } | |
2437 | ||
2438 | /** | |
2439 | * audit_set_loginuid - set current task's loginuid | |
2440 | * @loginuid: loginuid value | |
2441 | * | |
2442 | * Returns 0. | |
2443 | * | |
2444 | * Called (set) from fs/proc/base.c::proc_loginuid_write(). | |
2445 | */ | |
2446 | int audit_set_loginuid(kuid_t loginuid) | |
2447 | { | |
2448 | unsigned int oldsessionid, sessionid = AUDIT_SID_UNSET; | |
2449 | kuid_t oldloginuid; | |
2450 | int rc; | |
2451 | ||
2452 | oldloginuid = audit_get_loginuid(current); | |
2453 | oldsessionid = audit_get_sessionid(current); | |
2454 | ||
2455 | rc = audit_set_loginuid_perm(loginuid); | |
2456 | if (rc) | |
2457 | goto out; | |
2458 | ||
2459 | /* are we setting or clearing? */ | |
2460 | if (uid_valid(loginuid)) { | |
2461 | sessionid = (unsigned int)atomic_inc_return(&session_id); | |
2462 | if (unlikely(sessionid == AUDIT_SID_UNSET)) | |
2463 | sessionid = (unsigned int)atomic_inc_return(&session_id); | |
2464 | } | |
2465 | ||
2466 | current->sessionid = sessionid; | |
2467 | current->loginuid = loginuid; | |
2468 | out: | |
2469 | audit_log_set_loginuid(oldloginuid, loginuid, oldsessionid, sessionid, rc); | |
2470 | return rc; | |
2471 | } | |
2472 | ||
2473 | /** | |
2474 | * audit_signal_info - record signal info for shutting down audit subsystem | |
2475 | * @sig: signal value | |
2476 | * @t: task being signaled | |
2477 | * | |
2478 | * If the audit subsystem is being terminated, record the task (pid) | |
2479 | * and uid that is doing that. | |
2480 | */ | |
2481 | int audit_signal_info(int sig, struct task_struct *t) | |
2482 | { | |
2483 | kuid_t uid = current_uid(), auid; | |
2484 | ||
2485 | if (auditd_test_task(t) && | |
2486 | (sig == SIGTERM || sig == SIGHUP || | |
2487 | sig == SIGUSR1 || sig == SIGUSR2)) { | |
2488 | audit_sig_pid = task_tgid_nr(current); | |
2489 | auid = audit_get_loginuid(current); | |
2490 | if (uid_valid(auid)) | |
2491 | audit_sig_uid = auid; | |
2492 | else | |
2493 | audit_sig_uid = uid; | |
2494 | security_task_getsecid_subj(current, &audit_sig_lsm); | |
2495 | } | |
2496 | ||
2497 | return audit_signal_info_syscall(t); | |
2498 | } | |
2499 | ||
2500 | /** | |
2501 | * audit_log_end - end one audit record | |
2502 | * @ab: the audit_buffer | |
2503 | * | |
2504 | * We can not do a netlink send inside an irq context because it blocks (last | |
2505 | * arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a | |
2506 | * queue and a kthread is scheduled to remove them from the queue outside the | |
2507 | * irq context. May be called in any context. | |
2508 | */ | |
2509 | void audit_log_end(struct audit_buffer *ab) | |
2510 | { | |
2511 | struct sk_buff *skb; | |
2512 | struct nlmsghdr *nlh; | |
2513 | ||
2514 | if (!ab) | |
2515 | return; | |
2516 | ||
2517 | if (audit_rate_check()) { | |
2518 | skb = ab->skb; | |
2519 | ab->skb = NULL; | |
2520 | ||
2521 | /* setup the netlink header, see the comments in | |
2522 | * kauditd_send_multicast_skb() for length quirks */ | |
2523 | nlh = nlmsg_hdr(skb); | |
2524 | nlh->nlmsg_len = skb->len - NLMSG_HDRLEN; | |
2525 | ||
2526 | /* queue the netlink packet and poke the kauditd thread */ | |
2527 | skb_queue_tail(&audit_queue, skb); | |
2528 | wake_up_interruptible(&kauditd_wait); | |
2529 | } else | |
2530 | audit_log_lost("rate limit exceeded"); | |
2531 | ||
2532 | audit_buffer_free(ab); | |
2533 | } | |
2534 | ||
2535 | /** | |
2536 | * audit_log - Log an audit record | |
2537 | * @ctx: audit context | |
2538 | * @gfp_mask: type of allocation | |
2539 | * @type: audit message type | |
2540 | * @fmt: format string to use | |
2541 | * @...: variable parameters matching the format string | |
2542 | * | |
2543 | * This is a convenience function that calls audit_log_start, | |
2544 | * audit_log_vformat, and audit_log_end. It may be called | |
2545 | * in any context. | |
2546 | */ | |
2547 | void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type, | |
2548 | const char *fmt, ...) | |
2549 | { | |
2550 | struct audit_buffer *ab; | |
2551 | va_list args; | |
2552 | ||
2553 | ab = audit_log_start(ctx, gfp_mask, type); | |
2554 | if (ab) { | |
2555 | va_start(args, fmt); | |
2556 | audit_log_vformat(ab, fmt, args); | |
2557 | va_end(args); | |
2558 | audit_log_end(ab); | |
2559 | } | |
2560 | } | |
2561 | ||
2562 | EXPORT_SYMBOL(audit_log_start); | |
2563 | EXPORT_SYMBOL(audit_log_end); | |
2564 | EXPORT_SYMBOL(audit_log_format); | |
2565 | EXPORT_SYMBOL(audit_log); |