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