Commit | Line | Data |
---|---|---|
85c8721f | 1 | /* audit.c -- Auditing support |
1da177e4 LT |
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 | * | |
6a01b07f | 5 | * Copyright 2003-2007 Red Hat Inc., Durham, North Carolina. |
1da177e4 LT |
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 SELinux. | |
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 | * | |
85c8721f | 41 | * Example user-space utilities: http://people.redhat.com/sgrubb/audit/ |
1da177e4 LT |
42 | */ |
43 | ||
44 | #include <linux/init.h> | |
1da177e4 | 45 | #include <asm/types.h> |
715b49ef | 46 | #include <asm/atomic.h> |
1da177e4 LT |
47 | #include <linux/mm.h> |
48 | #include <linux/module.h> | |
b7d11258 DW |
49 | #include <linux/err.h> |
50 | #include <linux/kthread.h> | |
1da177e4 LT |
51 | |
52 | #include <linux/audit.h> | |
53 | ||
54 | #include <net/sock.h> | |
93315ed6 | 55 | #include <net/netlink.h> |
1da177e4 LT |
56 | #include <linux/skbuff.h> |
57 | #include <linux/netlink.h> | |
3dc7e315 | 58 | #include <linux/selinux.h> |
f368c07d | 59 | #include <linux/inotify.h> |
7dfb7103 | 60 | #include <linux/freezer.h> |
522ed776 | 61 | #include <linux/tty.h> |
3dc7e315 DG |
62 | |
63 | #include "audit.h" | |
1da177e4 LT |
64 | |
65 | /* No auditing will take place until audit_initialized != 0. | |
66 | * (Initialization happens after skb_init is called.) */ | |
67 | static int audit_initialized; | |
68 | ||
6a01b07f SG |
69 | /* 0 - no auditing |
70 | * 1 - auditing enabled | |
71 | * 2 - auditing enabled and configuration is locked/unchangeable. */ | |
1da177e4 LT |
72 | int audit_enabled; |
73 | ||
74 | /* Default state when kernel boots without any parameters. */ | |
75 | static int audit_default; | |
76 | ||
77 | /* If auditing cannot proceed, audit_failure selects what happens. */ | |
78 | static int audit_failure = AUDIT_FAIL_PRINTK; | |
79 | ||
80 | /* If audit records are to be written to the netlink socket, audit_pid | |
81 | * contains the (non-zero) pid. */ | |
c2f0c7c3 | 82 | int audit_pid; |
1da177e4 | 83 | |
b0dd25a8 | 84 | /* If audit_rate_limit is non-zero, limit the rate of sending audit records |
1da177e4 LT |
85 | * to that number per second. This prevents DoS attacks, but results in |
86 | * audit records being dropped. */ | |
87 | static int audit_rate_limit; | |
88 | ||
89 | /* Number of outstanding audit_buffers allowed. */ | |
90 | static int audit_backlog_limit = 64; | |
ac4cec44 DW |
91 | static int audit_backlog_wait_time = 60 * HZ; |
92 | static int audit_backlog_wait_overflow = 0; | |
1da177e4 | 93 | |
c2f0c7c3 SG |
94 | /* The identity of the user shutting down the audit system. */ |
95 | uid_t audit_sig_uid = -1; | |
96 | pid_t audit_sig_pid = -1; | |
e1396065 | 97 | u32 audit_sig_sid = 0; |
c2f0c7c3 | 98 | |
1da177e4 LT |
99 | /* Records can be lost in several ways: |
100 | 0) [suppressed in audit_alloc] | |
101 | 1) out of memory in audit_log_start [kmalloc of struct audit_buffer] | |
102 | 2) out of memory in audit_log_move [alloc_skb] | |
103 | 3) suppressed due to audit_rate_limit | |
104 | 4) suppressed due to audit_backlog_limit | |
105 | */ | |
106 | static atomic_t audit_lost = ATOMIC_INIT(0); | |
107 | ||
108 | /* The netlink socket. */ | |
109 | static struct sock *audit_sock; | |
110 | ||
f368c07d AG |
111 | /* Inotify handle. */ |
112 | struct inotify_handle *audit_ih; | |
113 | ||
114 | /* Hash for inode-based rules */ | |
115 | struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS]; | |
116 | ||
b7d11258 | 117 | /* The audit_freelist is a list of pre-allocated audit buffers (if more |
1da177e4 LT |
118 | * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of |
119 | * being placed on the freelist). */ | |
1da177e4 | 120 | static DEFINE_SPINLOCK(audit_freelist_lock); |
b0dd25a8 | 121 | static int audit_freelist_count; |
1da177e4 LT |
122 | static LIST_HEAD(audit_freelist); |
123 | ||
b7d11258 DW |
124 | static struct sk_buff_head audit_skb_queue; |
125 | static struct task_struct *kauditd_task; | |
126 | static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait); | |
9ad9ad38 | 127 | static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait); |
1da177e4 | 128 | |
f368c07d AG |
129 | /* Serialize requests from userspace. */ |
130 | static DEFINE_MUTEX(audit_cmd_mutex); | |
1da177e4 LT |
131 | |
132 | /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting | |
133 | * audit records. Since printk uses a 1024 byte buffer, this buffer | |
134 | * should be at least that large. */ | |
135 | #define AUDIT_BUFSIZ 1024 | |
136 | ||
137 | /* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the | |
138 | * audit_freelist. Doing so eliminates many kmalloc/kfree calls. */ | |
139 | #define AUDIT_MAXFREE (2*NR_CPUS) | |
140 | ||
141 | /* The audit_buffer is used when formatting an audit record. The caller | |
142 | * locks briefly to get the record off the freelist or to allocate the | |
143 | * buffer, and locks briefly to send the buffer to the netlink layer or | |
144 | * to place it on a transmit queue. Multiple audit_buffers can be in | |
145 | * use simultaneously. */ | |
146 | struct audit_buffer { | |
147 | struct list_head list; | |
8fc6115c | 148 | struct sk_buff *skb; /* formatted skb ready to send */ |
1da177e4 | 149 | struct audit_context *ctx; /* NULL or associated context */ |
9796fdd8 | 150 | gfp_t gfp_mask; |
1da177e4 LT |
151 | }; |
152 | ||
c0404993 SG |
153 | static void audit_set_pid(struct audit_buffer *ab, pid_t pid) |
154 | { | |
b529ccf2 | 155 | struct nlmsghdr *nlh = nlmsg_hdr(ab->skb); |
c0404993 SG |
156 | nlh->nlmsg_pid = pid; |
157 | } | |
158 | ||
8c8570fb | 159 | void audit_panic(const char *message) |
1da177e4 LT |
160 | { |
161 | switch (audit_failure) | |
162 | { | |
163 | case AUDIT_FAIL_SILENT: | |
164 | break; | |
165 | case AUDIT_FAIL_PRINTK: | |
166 | printk(KERN_ERR "audit: %s\n", message); | |
167 | break; | |
168 | case AUDIT_FAIL_PANIC: | |
169 | panic("audit: %s\n", message); | |
170 | break; | |
171 | } | |
172 | } | |
173 | ||
174 | static inline int audit_rate_check(void) | |
175 | { | |
176 | static unsigned long last_check = 0; | |
177 | static int messages = 0; | |
178 | static DEFINE_SPINLOCK(lock); | |
179 | unsigned long flags; | |
180 | unsigned long now; | |
181 | unsigned long elapsed; | |
182 | int retval = 0; | |
183 | ||
184 | if (!audit_rate_limit) return 1; | |
185 | ||
186 | spin_lock_irqsave(&lock, flags); | |
187 | if (++messages < audit_rate_limit) { | |
188 | retval = 1; | |
189 | } else { | |
190 | now = jiffies; | |
191 | elapsed = now - last_check; | |
192 | if (elapsed > HZ) { | |
193 | last_check = now; | |
194 | messages = 0; | |
195 | retval = 1; | |
196 | } | |
197 | } | |
198 | spin_unlock_irqrestore(&lock, flags); | |
199 | ||
200 | return retval; | |
201 | } | |
202 | ||
b0dd25a8 RD |
203 | /** |
204 | * audit_log_lost - conditionally log lost audit message event | |
205 | * @message: the message stating reason for lost audit message | |
206 | * | |
207 | * Emit at least 1 message per second, even if audit_rate_check is | |
208 | * throttling. | |
209 | * Always increment the lost messages counter. | |
210 | */ | |
1da177e4 LT |
211 | void audit_log_lost(const char *message) |
212 | { | |
213 | static unsigned long last_msg = 0; | |
214 | static DEFINE_SPINLOCK(lock); | |
215 | unsigned long flags; | |
216 | unsigned long now; | |
217 | int print; | |
218 | ||
219 | atomic_inc(&audit_lost); | |
220 | ||
221 | print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit); | |
222 | ||
223 | if (!print) { | |
224 | spin_lock_irqsave(&lock, flags); | |
225 | now = jiffies; | |
226 | if (now - last_msg > HZ) { | |
227 | print = 1; | |
228 | last_msg = now; | |
229 | } | |
230 | spin_unlock_irqrestore(&lock, flags); | |
231 | } | |
232 | ||
233 | if (print) { | |
234 | printk(KERN_WARNING | |
b7d11258 | 235 | "audit: audit_lost=%d audit_rate_limit=%d audit_backlog_limit=%d\n", |
1da177e4 | 236 | atomic_read(&audit_lost), |
1da177e4 LT |
237 | audit_rate_limit, |
238 | audit_backlog_limit); | |
239 | audit_panic(message); | |
240 | } | |
1da177e4 LT |
241 | } |
242 | ||
ce29b682 | 243 | static int audit_set_rate_limit(int limit, uid_t loginuid, u32 sid) |
1da177e4 | 244 | { |
6a01b07f SG |
245 | int res, rc = 0, old = audit_rate_limit; |
246 | ||
247 | /* check if we are locked */ | |
248 | if (audit_enabled == 2) | |
249 | res = 0; | |
250 | else | |
251 | res = 1; | |
ce29b682 SG |
252 | |
253 | if (sid) { | |
254 | char *ctx = NULL; | |
255 | u32 len; | |
6a01b07f | 256 | if ((rc = selinux_sid_to_string(sid, &ctx, &len)) == 0) { |
ce29b682 | 257 | audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE, |
6a01b07f SG |
258 | "audit_rate_limit=%d old=%d by auid=%u" |
259 | " subj=%s res=%d", | |
260 | limit, old, loginuid, ctx, res); | |
261 | kfree(ctx); | |
262 | } else | |
263 | res = 0; /* Something weird, deny request */ | |
264 | } | |
265 | audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE, | |
266 | "audit_rate_limit=%d old=%d by auid=%u res=%d", | |
267 | limit, old, loginuid, res); | |
268 | ||
269 | /* If we are allowed, make the change */ | |
270 | if (res == 1) | |
271 | audit_rate_limit = limit; | |
272 | /* Not allowed, update reason */ | |
273 | else if (rc == 0) | |
274 | rc = -EPERM; | |
275 | return rc; | |
1da177e4 LT |
276 | } |
277 | ||
ce29b682 | 278 | static int audit_set_backlog_limit(int limit, uid_t loginuid, u32 sid) |
1da177e4 | 279 | { |
6a01b07f SG |
280 | int res, rc = 0, old = audit_backlog_limit; |
281 | ||
282 | /* check if we are locked */ | |
283 | if (audit_enabled == 2) | |
284 | res = 0; | |
285 | else | |
286 | res = 1; | |
ce29b682 SG |
287 | |
288 | if (sid) { | |
289 | char *ctx = NULL; | |
290 | u32 len; | |
6a01b07f | 291 | if ((rc = selinux_sid_to_string(sid, &ctx, &len)) == 0) { |
ce29b682 | 292 | audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE, |
6a01b07f SG |
293 | "audit_backlog_limit=%d old=%d by auid=%u" |
294 | " subj=%s res=%d", | |
295 | limit, old, loginuid, ctx, res); | |
296 | kfree(ctx); | |
297 | } else | |
298 | res = 0; /* Something weird, deny request */ | |
299 | } | |
300 | audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE, | |
301 | "audit_backlog_limit=%d old=%d by auid=%u res=%d", | |
302 | limit, old, loginuid, res); | |
303 | ||
304 | /* If we are allowed, make the change */ | |
305 | if (res == 1) | |
306 | audit_backlog_limit = limit; | |
307 | /* Not allowed, update reason */ | |
308 | else if (rc == 0) | |
309 | rc = -EPERM; | |
310 | return rc; | |
1da177e4 LT |
311 | } |
312 | ||
ce29b682 | 313 | static int audit_set_enabled(int state, uid_t loginuid, u32 sid) |
1da177e4 | 314 | { |
6a01b07f | 315 | int res, rc = 0, old = audit_enabled; |
ce29b682 | 316 | |
6a01b07f | 317 | if (state < 0 || state > 2) |
1da177e4 | 318 | return -EINVAL; |
ce29b682 | 319 | |
6a01b07f SG |
320 | /* check if we are locked */ |
321 | if (audit_enabled == 2) | |
322 | res = 0; | |
323 | else | |
324 | res = 1; | |
325 | ||
ce29b682 SG |
326 | if (sid) { |
327 | char *ctx = NULL; | |
328 | u32 len; | |
6a01b07f | 329 | if ((rc = selinux_sid_to_string(sid, &ctx, &len)) == 0) { |
ce29b682 | 330 | audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE, |
6a01b07f SG |
331 | "audit_enabled=%d old=%d by auid=%u" |
332 | " subj=%s res=%d", | |
333 | state, old, loginuid, ctx, res); | |
334 | kfree(ctx); | |
335 | } else | |
336 | res = 0; /* Something weird, deny request */ | |
337 | } | |
338 | audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE, | |
339 | "audit_enabled=%d old=%d by auid=%u res=%d", | |
340 | state, old, loginuid, res); | |
341 | ||
342 | /* If we are allowed, make the change */ | |
343 | if (res == 1) | |
344 | audit_enabled = state; | |
345 | /* Not allowed, update reason */ | |
346 | else if (rc == 0) | |
347 | rc = -EPERM; | |
348 | return rc; | |
1da177e4 LT |
349 | } |
350 | ||
ce29b682 | 351 | static int audit_set_failure(int state, uid_t loginuid, u32 sid) |
1da177e4 | 352 | { |
6a01b07f | 353 | int res, rc = 0, old = audit_failure; |
ce29b682 | 354 | |
1da177e4 LT |
355 | if (state != AUDIT_FAIL_SILENT |
356 | && state != AUDIT_FAIL_PRINTK | |
357 | && state != AUDIT_FAIL_PANIC) | |
358 | return -EINVAL; | |
ce29b682 | 359 | |
6a01b07f SG |
360 | /* check if we are locked */ |
361 | if (audit_enabled == 2) | |
362 | res = 0; | |
363 | else | |
364 | res = 1; | |
365 | ||
ce29b682 SG |
366 | if (sid) { |
367 | char *ctx = NULL; | |
368 | u32 len; | |
6a01b07f | 369 | if ((rc = selinux_sid_to_string(sid, &ctx, &len)) == 0) { |
ce29b682 | 370 | audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE, |
6a01b07f SG |
371 | "audit_failure=%d old=%d by auid=%u" |
372 | " subj=%s res=%d", | |
373 | state, old, loginuid, ctx, res); | |
374 | kfree(ctx); | |
375 | } else | |
376 | res = 0; /* Something weird, deny request */ | |
377 | } | |
378 | audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE, | |
379 | "audit_failure=%d old=%d by auid=%u res=%d", | |
380 | state, old, loginuid, res); | |
381 | ||
382 | /* If we are allowed, make the change */ | |
383 | if (res == 1) | |
384 | audit_failure = state; | |
385 | /* Not allowed, update reason */ | |
386 | else if (rc == 0) | |
387 | rc = -EPERM; | |
388 | return rc; | |
1da177e4 LT |
389 | } |
390 | ||
97a41e26 | 391 | static int kauditd_thread(void *dummy) |
b7d11258 DW |
392 | { |
393 | struct sk_buff *skb; | |
394 | ||
83144186 | 395 | set_freezable(); |
4899b8b1 | 396 | while (!kthread_should_stop()) { |
b7d11258 | 397 | skb = skb_dequeue(&audit_skb_queue); |
9ad9ad38 | 398 | wake_up(&audit_backlog_wait); |
b7d11258 DW |
399 | if (skb) { |
400 | if (audit_pid) { | |
401 | int err = netlink_unicast(audit_sock, skb, audit_pid, 0); | |
402 | if (err < 0) { | |
403 | BUG_ON(err != -ECONNREFUSED); /* Shoudn't happen */ | |
404 | printk(KERN_ERR "audit: *NO* daemon at audit_pid=%d\n", audit_pid); | |
405 | audit_pid = 0; | |
406 | } | |
407 | } else { | |
e1b09eba | 408 | printk(KERN_NOTICE "%s\n", skb->data + NLMSG_SPACE(0)); |
b7d11258 DW |
409 | kfree_skb(skb); |
410 | } | |
411 | } else { | |
412 | DECLARE_WAITQUEUE(wait, current); | |
413 | set_current_state(TASK_INTERRUPTIBLE); | |
414 | add_wait_queue(&kauditd_wait, &wait); | |
415 | ||
7a4ae749 PO |
416 | if (!skb_queue_len(&audit_skb_queue)) { |
417 | try_to_freeze(); | |
b7d11258 | 418 | schedule(); |
7a4ae749 | 419 | } |
b7d11258 DW |
420 | |
421 | __set_current_state(TASK_RUNNING); | |
422 | remove_wait_queue(&kauditd_wait, &wait); | |
423 | } | |
424 | } | |
4899b8b1 | 425 | return 0; |
b7d11258 DW |
426 | } |
427 | ||
522ed776 MT |
428 | static int audit_prepare_user_tty(pid_t pid, uid_t loginuid) |
429 | { | |
430 | struct task_struct *tsk; | |
431 | int err; | |
432 | ||
433 | read_lock(&tasklist_lock); | |
434 | tsk = find_task_by_pid(pid); | |
435 | err = -ESRCH; | |
436 | if (!tsk) | |
437 | goto out; | |
438 | err = 0; | |
439 | ||
440 | spin_lock_irq(&tsk->sighand->siglock); | |
441 | if (!tsk->signal->audit_tty) | |
442 | err = -EPERM; | |
443 | spin_unlock_irq(&tsk->sighand->siglock); | |
444 | if (err) | |
445 | goto out; | |
446 | ||
447 | tty_audit_push_task(tsk, loginuid); | |
448 | out: | |
449 | read_unlock(&tasklist_lock); | |
450 | return err; | |
451 | } | |
452 | ||
9044e6bc AV |
453 | int audit_send_list(void *_dest) |
454 | { | |
455 | struct audit_netlink_list *dest = _dest; | |
456 | int pid = dest->pid; | |
457 | struct sk_buff *skb; | |
458 | ||
459 | /* wait for parent to finish and send an ACK */ | |
f368c07d AG |
460 | mutex_lock(&audit_cmd_mutex); |
461 | mutex_unlock(&audit_cmd_mutex); | |
9044e6bc AV |
462 | |
463 | while ((skb = __skb_dequeue(&dest->q)) != NULL) | |
464 | netlink_unicast(audit_sock, skb, pid, 0); | |
465 | ||
466 | kfree(dest); | |
467 | ||
468 | return 0; | |
469 | } | |
470 | ||
74c3cbe3 AV |
471 | #ifdef CONFIG_AUDIT_TREE |
472 | static int prune_tree_thread(void *unused) | |
473 | { | |
474 | mutex_lock(&audit_cmd_mutex); | |
475 | audit_prune_trees(); | |
476 | mutex_unlock(&audit_cmd_mutex); | |
477 | return 0; | |
478 | } | |
479 | ||
480 | void audit_schedule_prune(void) | |
481 | { | |
482 | kthread_run(prune_tree_thread, NULL, "audit_prune_tree"); | |
483 | } | |
484 | #endif | |
485 | ||
9044e6bc AV |
486 | struct sk_buff *audit_make_reply(int pid, int seq, int type, int done, |
487 | int multi, void *payload, int size) | |
488 | { | |
489 | struct sk_buff *skb; | |
490 | struct nlmsghdr *nlh; | |
491 | int len = NLMSG_SPACE(size); | |
492 | void *data; | |
493 | int flags = multi ? NLM_F_MULTI : 0; | |
494 | int t = done ? NLMSG_DONE : type; | |
495 | ||
496 | skb = alloc_skb(len, GFP_KERNEL); | |
497 | if (!skb) | |
498 | return NULL; | |
499 | ||
500 | nlh = NLMSG_PUT(skb, pid, seq, t, size); | |
501 | nlh->nlmsg_flags = flags; | |
502 | data = NLMSG_DATA(nlh); | |
503 | memcpy(data, payload, size); | |
504 | return skb; | |
505 | ||
506 | nlmsg_failure: /* Used by NLMSG_PUT */ | |
507 | if (skb) | |
508 | kfree_skb(skb); | |
509 | return NULL; | |
510 | } | |
511 | ||
b0dd25a8 RD |
512 | /** |
513 | * audit_send_reply - send an audit reply message via netlink | |
514 | * @pid: process id to send reply to | |
515 | * @seq: sequence number | |
516 | * @type: audit message type | |
517 | * @done: done (last) flag | |
518 | * @multi: multi-part message flag | |
519 | * @payload: payload data | |
520 | * @size: payload size | |
521 | * | |
522 | * Allocates an skb, builds the netlink message, and sends it to the pid. | |
523 | * No failure notifications. | |
524 | */ | |
1da177e4 LT |
525 | void audit_send_reply(int pid, int seq, int type, int done, int multi, |
526 | void *payload, int size) | |
527 | { | |
528 | struct sk_buff *skb; | |
9044e6bc | 529 | skb = audit_make_reply(pid, seq, type, done, multi, payload, size); |
1da177e4 | 530 | if (!skb) |
b7d11258 | 531 | return; |
b7d11258 DW |
532 | /* Ignore failure. It'll only happen if the sender goes away, |
533 | because our timeout is set to infinite. */ | |
534 | netlink_unicast(audit_sock, skb, pid, 0); | |
1da177e4 | 535 | return; |
1da177e4 LT |
536 | } |
537 | ||
538 | /* | |
539 | * Check for appropriate CAP_AUDIT_ capabilities on incoming audit | |
540 | * control messages. | |
541 | */ | |
c7bdb545 | 542 | static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type) |
1da177e4 LT |
543 | { |
544 | int err = 0; | |
545 | ||
546 | switch (msg_type) { | |
547 | case AUDIT_GET: | |
548 | case AUDIT_LIST: | |
93315ed6 | 549 | case AUDIT_LIST_RULES: |
1da177e4 LT |
550 | case AUDIT_SET: |
551 | case AUDIT_ADD: | |
93315ed6 | 552 | case AUDIT_ADD_RULE: |
1da177e4 | 553 | case AUDIT_DEL: |
93315ed6 | 554 | case AUDIT_DEL_RULE: |
c2f0c7c3 | 555 | case AUDIT_SIGNAL_INFO: |
522ed776 MT |
556 | case AUDIT_TTY_GET: |
557 | case AUDIT_TTY_SET: | |
74c3cbe3 AV |
558 | case AUDIT_TRIM: |
559 | case AUDIT_MAKE_EQUIV: | |
c7bdb545 | 560 | if (security_netlink_recv(skb, CAP_AUDIT_CONTROL)) |
1da177e4 LT |
561 | err = -EPERM; |
562 | break; | |
05474106 | 563 | case AUDIT_USER: |
039b6b3e RD |
564 | case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG: |
565 | case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2: | |
c7bdb545 | 566 | if (security_netlink_recv(skb, CAP_AUDIT_WRITE)) |
1da177e4 LT |
567 | err = -EPERM; |
568 | break; | |
569 | default: /* bad msg */ | |
570 | err = -EINVAL; | |
571 | } | |
572 | ||
573 | return err; | |
574 | } | |
575 | ||
576 | static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) | |
577 | { | |
e7c34970 | 578 | u32 uid, pid, seq, sid; |
1da177e4 LT |
579 | void *data; |
580 | struct audit_status *status_get, status_set; | |
581 | int err; | |
c0404993 | 582 | struct audit_buffer *ab; |
1da177e4 | 583 | u16 msg_type = nlh->nlmsg_type; |
c94c257c | 584 | uid_t loginuid; /* loginuid of sender */ |
e1396065 AV |
585 | struct audit_sig_info *sig_data; |
586 | char *ctx; | |
587 | u32 len; | |
1da177e4 | 588 | |
c7bdb545 | 589 | err = audit_netlink_ok(skb, msg_type); |
1da177e4 LT |
590 | if (err) |
591 | return err; | |
592 | ||
b0dd25a8 RD |
593 | /* As soon as there's any sign of userspace auditd, |
594 | * start kauditd to talk to it */ | |
b7d11258 DW |
595 | if (!kauditd_task) |
596 | kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd"); | |
597 | if (IS_ERR(kauditd_task)) { | |
598 | err = PTR_ERR(kauditd_task); | |
599 | kauditd_task = NULL; | |
600 | return err; | |
601 | } | |
602 | ||
1da177e4 LT |
603 | pid = NETLINK_CREDS(skb)->pid; |
604 | uid = NETLINK_CREDS(skb)->uid; | |
c94c257c | 605 | loginuid = NETLINK_CB(skb).loginuid; |
e7c34970 | 606 | sid = NETLINK_CB(skb).sid; |
1da177e4 LT |
607 | seq = nlh->nlmsg_seq; |
608 | data = NLMSG_DATA(nlh); | |
609 | ||
610 | switch (msg_type) { | |
611 | case AUDIT_GET: | |
612 | status_set.enabled = audit_enabled; | |
613 | status_set.failure = audit_failure; | |
614 | status_set.pid = audit_pid; | |
615 | status_set.rate_limit = audit_rate_limit; | |
616 | status_set.backlog_limit = audit_backlog_limit; | |
617 | status_set.lost = atomic_read(&audit_lost); | |
b7d11258 | 618 | status_set.backlog = skb_queue_len(&audit_skb_queue); |
1da177e4 LT |
619 | audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_GET, 0, 0, |
620 | &status_set, sizeof(status_set)); | |
621 | break; | |
622 | case AUDIT_SET: | |
623 | if (nlh->nlmsg_len < sizeof(struct audit_status)) | |
624 | return -EINVAL; | |
625 | status_get = (struct audit_status *)data; | |
626 | if (status_get->mask & AUDIT_STATUS_ENABLED) { | |
ce29b682 SG |
627 | err = audit_set_enabled(status_get->enabled, |
628 | loginuid, sid); | |
1da177e4 LT |
629 | if (err < 0) return err; |
630 | } | |
631 | if (status_get->mask & AUDIT_STATUS_FAILURE) { | |
ce29b682 SG |
632 | err = audit_set_failure(status_get->failure, |
633 | loginuid, sid); | |
1da177e4 LT |
634 | if (err < 0) return err; |
635 | } | |
636 | if (status_get->mask & AUDIT_STATUS_PID) { | |
637 | int old = audit_pid; | |
ce29b682 | 638 | if (sid) { |
1a70cd40 | 639 | if ((err = selinux_sid_to_string( |
ce29b682 | 640 | sid, &ctx, &len))) |
e1396065 | 641 | return err; |
ce29b682 SG |
642 | else |
643 | audit_log(NULL, GFP_KERNEL, | |
644 | AUDIT_CONFIG_CHANGE, | |
645 | "audit_pid=%d old=%d by auid=%u subj=%s", | |
646 | status_get->pid, old, | |
647 | loginuid, ctx); | |
648 | kfree(ctx); | |
649 | } else | |
650 | audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE, | |
651 | "audit_pid=%d old=%d by auid=%u", | |
652 | status_get->pid, old, loginuid); | |
1da177e4 | 653 | audit_pid = status_get->pid; |
1da177e4 LT |
654 | } |
655 | if (status_get->mask & AUDIT_STATUS_RATE_LIMIT) | |
5d136a01 | 656 | err = audit_set_rate_limit(status_get->rate_limit, |
ce29b682 | 657 | loginuid, sid); |
1da177e4 | 658 | if (status_get->mask & AUDIT_STATUS_BACKLOG_LIMIT) |
5d136a01 | 659 | err = audit_set_backlog_limit(status_get->backlog_limit, |
ce29b682 | 660 | loginuid, sid); |
1da177e4 | 661 | break; |
05474106 | 662 | case AUDIT_USER: |
039b6b3e RD |
663 | case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG: |
664 | case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2: | |
4a4cd633 DW |
665 | if (!audit_enabled && msg_type != AUDIT_USER_AVC) |
666 | return 0; | |
667 | ||
5bb289b5 | 668 | err = audit_filter_user(&NETLINK_CB(skb), msg_type); |
4a4cd633 DW |
669 | if (err == 1) { |
670 | err = 0; | |
522ed776 MT |
671 | if (msg_type == AUDIT_USER_TTY) { |
672 | err = audit_prepare_user_tty(pid, loginuid); | |
673 | if (err) | |
674 | break; | |
675 | } | |
9ad9ad38 | 676 | ab = audit_log_start(NULL, GFP_KERNEL, msg_type); |
4a4cd633 DW |
677 | if (ab) { |
678 | audit_log_format(ab, | |
e7c34970 SG |
679 | "user pid=%d uid=%u auid=%u", |
680 | pid, uid, loginuid); | |
681 | if (sid) { | |
1a70cd40 | 682 | if (selinux_sid_to_string( |
e7c34970 | 683 | sid, &ctx, &len)) { |
5600b892 | 684 | audit_log_format(ab, |
ce29b682 | 685 | " ssid=%u", sid); |
e7c34970 SG |
686 | /* Maybe call audit_panic? */ |
687 | } else | |
5600b892 | 688 | audit_log_format(ab, |
e7c34970 SG |
689 | " subj=%s", ctx); |
690 | kfree(ctx); | |
691 | } | |
522ed776 MT |
692 | if (msg_type != AUDIT_USER_TTY) |
693 | audit_log_format(ab, " msg='%.1024s'", | |
694 | (char *)data); | |
695 | else { | |
696 | int size; | |
697 | ||
698 | audit_log_format(ab, " msg="); | |
699 | size = nlmsg_len(nlh); | |
700 | audit_log_n_untrustedstring(ab, size, | |
701 | data); | |
702 | } | |
4a4cd633 DW |
703 | audit_set_pid(ab, pid); |
704 | audit_log_end(ab); | |
705 | } | |
0f45aa18 | 706 | } |
1da177e4 LT |
707 | break; |
708 | case AUDIT_ADD: | |
709 | case AUDIT_DEL: | |
93315ed6 | 710 | if (nlmsg_len(nlh) < sizeof(struct audit_rule)) |
1da177e4 | 711 | return -EINVAL; |
6a01b07f SG |
712 | if (audit_enabled == 2) { |
713 | ab = audit_log_start(NULL, GFP_KERNEL, | |
714 | AUDIT_CONFIG_CHANGE); | |
715 | if (ab) { | |
716 | audit_log_format(ab, | |
717 | "pid=%d uid=%u auid=%u", | |
718 | pid, uid, loginuid); | |
719 | if (sid) { | |
720 | if (selinux_sid_to_string( | |
721 | sid, &ctx, &len)) { | |
722 | audit_log_format(ab, | |
723 | " ssid=%u", sid); | |
724 | /* Maybe call audit_panic? */ | |
725 | } else | |
726 | audit_log_format(ab, | |
727 | " subj=%s", ctx); | |
728 | kfree(ctx); | |
729 | } | |
730 | audit_log_format(ab, " audit_enabled=%d res=0", | |
731 | audit_enabled); | |
732 | audit_log_end(ab); | |
733 | } | |
734 | return -EPERM; | |
735 | } | |
1da177e4 LT |
736 | /* fallthrough */ |
737 | case AUDIT_LIST: | |
1da177e4 | 738 | err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid, |
93315ed6 | 739 | uid, seq, data, nlmsg_len(nlh), |
ce29b682 | 740 | loginuid, sid); |
93315ed6 AG |
741 | break; |
742 | case AUDIT_ADD_RULE: | |
743 | case AUDIT_DEL_RULE: | |
744 | if (nlmsg_len(nlh) < sizeof(struct audit_rule_data)) | |
745 | return -EINVAL; | |
6a01b07f SG |
746 | if (audit_enabled == 2) { |
747 | ab = audit_log_start(NULL, GFP_KERNEL, | |
748 | AUDIT_CONFIG_CHANGE); | |
749 | if (ab) { | |
750 | audit_log_format(ab, | |
751 | "pid=%d uid=%u auid=%u", | |
752 | pid, uid, loginuid); | |
753 | if (sid) { | |
754 | if (selinux_sid_to_string( | |
755 | sid, &ctx, &len)) { | |
756 | audit_log_format(ab, | |
757 | " ssid=%u", sid); | |
758 | /* Maybe call audit_panic? */ | |
759 | } else | |
760 | audit_log_format(ab, | |
761 | " subj=%s", ctx); | |
762 | kfree(ctx); | |
763 | } | |
764 | audit_log_format(ab, " audit_enabled=%d res=0", | |
765 | audit_enabled); | |
766 | audit_log_end(ab); | |
767 | } | |
768 | return -EPERM; | |
769 | } | |
93315ed6 AG |
770 | /* fallthrough */ |
771 | case AUDIT_LIST_RULES: | |
772 | err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid, | |
773 | uid, seq, data, nlmsg_len(nlh), | |
ce29b682 | 774 | loginuid, sid); |
1da177e4 | 775 | break; |
74c3cbe3 AV |
776 | case AUDIT_TRIM: |
777 | audit_trim_trees(); | |
778 | ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE); | |
779 | if (!ab) | |
780 | break; | |
781 | audit_log_format(ab, "auid=%u", loginuid); | |
782 | if (sid) { | |
783 | u32 len; | |
784 | ctx = NULL; | |
785 | if (selinux_sid_to_string(sid, &ctx, &len)) | |
786 | audit_log_format(ab, " ssid=%u", sid); | |
787 | else | |
788 | audit_log_format(ab, " subj=%s", ctx); | |
789 | kfree(ctx); | |
790 | } | |
791 | audit_log_format(ab, " op=trim res=1"); | |
792 | audit_log_end(ab); | |
793 | break; | |
794 | case AUDIT_MAKE_EQUIV: { | |
795 | void *bufp = data; | |
796 | u32 sizes[2]; | |
797 | size_t len = nlmsg_len(nlh); | |
798 | char *old, *new; | |
799 | ||
800 | err = -EINVAL; | |
801 | if (len < 2 * sizeof(u32)) | |
802 | break; | |
803 | memcpy(sizes, bufp, 2 * sizeof(u32)); | |
804 | bufp += 2 * sizeof(u32); | |
805 | len -= 2 * sizeof(u32); | |
806 | old = audit_unpack_string(&bufp, &len, sizes[0]); | |
807 | if (IS_ERR(old)) { | |
808 | err = PTR_ERR(old); | |
809 | break; | |
810 | } | |
811 | new = audit_unpack_string(&bufp, &len, sizes[1]); | |
812 | if (IS_ERR(new)) { | |
813 | err = PTR_ERR(new); | |
814 | kfree(old); | |
815 | break; | |
816 | } | |
817 | /* OK, here comes... */ | |
818 | err = audit_tag_tree(old, new); | |
819 | ||
820 | ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE); | |
821 | if (!ab) { | |
822 | kfree(old); | |
823 | kfree(new); | |
824 | break; | |
825 | } | |
826 | audit_log_format(ab, "auid=%u", loginuid); | |
827 | if (sid) { | |
828 | u32 len; | |
829 | ctx = NULL; | |
830 | if (selinux_sid_to_string(sid, &ctx, &len)) | |
831 | audit_log_format(ab, " ssid=%u", sid); | |
832 | else | |
833 | audit_log_format(ab, " subj=%s", ctx); | |
834 | kfree(ctx); | |
835 | } | |
836 | audit_log_format(ab, " op=make_equiv old="); | |
837 | audit_log_untrustedstring(ab, old); | |
838 | audit_log_format(ab, " new="); | |
839 | audit_log_untrustedstring(ab, new); | |
840 | audit_log_format(ab, " res=%d", !err); | |
841 | audit_log_end(ab); | |
842 | kfree(old); | |
843 | kfree(new); | |
844 | break; | |
845 | } | |
c2f0c7c3 | 846 | case AUDIT_SIGNAL_INFO: |
1a70cd40 | 847 | err = selinux_sid_to_string(audit_sig_sid, &ctx, &len); |
e1396065 AV |
848 | if (err) |
849 | return err; | |
850 | sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL); | |
851 | if (!sig_data) { | |
852 | kfree(ctx); | |
853 | return -ENOMEM; | |
854 | } | |
855 | sig_data->uid = audit_sig_uid; | |
856 | sig_data->pid = audit_sig_pid; | |
857 | memcpy(sig_data->ctx, ctx, len); | |
858 | kfree(ctx); | |
5600b892 | 859 | audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_SIGNAL_INFO, |
e1396065 AV |
860 | 0, 0, sig_data, sizeof(*sig_data) + len); |
861 | kfree(sig_data); | |
c2f0c7c3 | 862 | break; |
522ed776 MT |
863 | case AUDIT_TTY_GET: { |
864 | struct audit_tty_status s; | |
865 | struct task_struct *tsk; | |
866 | ||
867 | read_lock(&tasklist_lock); | |
868 | tsk = find_task_by_pid(pid); | |
869 | if (!tsk) | |
870 | err = -ESRCH; | |
871 | else { | |
872 | spin_lock_irq(&tsk->sighand->siglock); | |
873 | s.enabled = tsk->signal->audit_tty != 0; | |
874 | spin_unlock_irq(&tsk->sighand->siglock); | |
875 | } | |
876 | read_unlock(&tasklist_lock); | |
877 | audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_TTY_GET, 0, 0, | |
878 | &s, sizeof(s)); | |
879 | break; | |
880 | } | |
881 | case AUDIT_TTY_SET: { | |
882 | struct audit_tty_status *s; | |
883 | struct task_struct *tsk; | |
884 | ||
885 | if (nlh->nlmsg_len < sizeof(struct audit_tty_status)) | |
886 | return -EINVAL; | |
887 | s = data; | |
888 | if (s->enabled != 0 && s->enabled != 1) | |
889 | return -EINVAL; | |
890 | read_lock(&tasklist_lock); | |
891 | tsk = find_task_by_pid(pid); | |
892 | if (!tsk) | |
893 | err = -ESRCH; | |
894 | else { | |
895 | spin_lock_irq(&tsk->sighand->siglock); | |
896 | tsk->signal->audit_tty = s->enabled != 0; | |
897 | spin_unlock_irq(&tsk->sighand->siglock); | |
898 | } | |
899 | read_unlock(&tasklist_lock); | |
900 | break; | |
901 | } | |
1da177e4 LT |
902 | default: |
903 | err = -EINVAL; | |
904 | break; | |
905 | } | |
906 | ||
907 | return err < 0 ? err : 0; | |
908 | } | |
909 | ||
b0dd25a8 RD |
910 | /* |
911 | * Get message from skb (based on rtnetlink_rcv_skb). Each message is | |
1da177e4 | 912 | * processed by audit_receive_msg. Malformed skbs with wrong length are |
b0dd25a8 RD |
913 | * discarded silently. |
914 | */ | |
2a0a6ebe | 915 | static void audit_receive_skb(struct sk_buff *skb) |
1da177e4 LT |
916 | { |
917 | int err; | |
918 | struct nlmsghdr *nlh; | |
919 | u32 rlen; | |
920 | ||
921 | while (skb->len >= NLMSG_SPACE(0)) { | |
b529ccf2 | 922 | nlh = nlmsg_hdr(skb); |
1da177e4 | 923 | if (nlh->nlmsg_len < sizeof(*nlh) || skb->len < nlh->nlmsg_len) |
2a0a6ebe | 924 | return; |
1da177e4 LT |
925 | rlen = NLMSG_ALIGN(nlh->nlmsg_len); |
926 | if (rlen > skb->len) | |
927 | rlen = skb->len; | |
928 | if ((err = audit_receive_msg(skb, nlh))) { | |
929 | netlink_ack(skb, nlh, err); | |
930 | } else if (nlh->nlmsg_flags & NLM_F_ACK) | |
931 | netlink_ack(skb, nlh, 0); | |
932 | skb_pull(skb, rlen); | |
933 | } | |
1da177e4 LT |
934 | } |
935 | ||
936 | /* Receive messages from netlink socket. */ | |
cd40b7d3 | 937 | static void audit_receive(struct sk_buff *skb) |
1da177e4 | 938 | { |
f368c07d | 939 | mutex_lock(&audit_cmd_mutex); |
cd40b7d3 | 940 | audit_receive_skb(skb); |
f368c07d | 941 | mutex_unlock(&audit_cmd_mutex); |
1da177e4 LT |
942 | } |
943 | ||
f368c07d AG |
944 | #ifdef CONFIG_AUDITSYSCALL |
945 | static const struct inotify_operations audit_inotify_ops = { | |
946 | .handle_event = audit_handle_ievent, | |
947 | .destroy_watch = audit_free_parent, | |
948 | }; | |
949 | #endif | |
1da177e4 LT |
950 | |
951 | /* Initialize audit support at boot time. */ | |
952 | static int __init audit_init(void) | |
953 | { | |
f368c07d | 954 | int i; |
f368c07d | 955 | |
1da177e4 LT |
956 | printk(KERN_INFO "audit: initializing netlink socket (%s)\n", |
957 | audit_default ? "enabled" : "disabled"); | |
b4b51029 EB |
958 | audit_sock = netlink_kernel_create(&init_net, NETLINK_AUDIT, 0, |
959 | audit_receive, NULL, THIS_MODULE); | |
1da177e4 LT |
960 | if (!audit_sock) |
961 | audit_panic("cannot initialize netlink socket"); | |
71e1c784 AG |
962 | else |
963 | audit_sock->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT; | |
1da177e4 | 964 | |
b7d11258 | 965 | skb_queue_head_init(&audit_skb_queue); |
1da177e4 LT |
966 | audit_initialized = 1; |
967 | audit_enabled = audit_default; | |
3dc7e315 DG |
968 | |
969 | /* Register the callback with selinux. This callback will be invoked | |
970 | * when a new policy is loaded. */ | |
971 | selinux_audit_set_callback(&selinux_audit_rule_update); | |
972 | ||
9ad9ad38 | 973 | audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized"); |
f368c07d AG |
974 | |
975 | #ifdef CONFIG_AUDITSYSCALL | |
976 | audit_ih = inotify_init(&audit_inotify_ops); | |
977 | if (IS_ERR(audit_ih)) | |
978 | audit_panic("cannot initialize inotify handle"); | |
6988434e | 979 | #endif |
f368c07d AG |
980 | |
981 | for (i = 0; i < AUDIT_INODE_BUCKETS; i++) | |
982 | INIT_LIST_HEAD(&audit_inode_hash[i]); | |
f368c07d | 983 | |
1da177e4 LT |
984 | return 0; |
985 | } | |
1da177e4 LT |
986 | __initcall(audit_init); |
987 | ||
988 | /* Process kernel command-line parameter at boot time. audit=0 or audit=1. */ | |
989 | static int __init audit_enable(char *str) | |
990 | { | |
991 | audit_default = !!simple_strtol(str, NULL, 0); | |
992 | printk(KERN_INFO "audit: %s%s\n", | |
993 | audit_default ? "enabled" : "disabled", | |
994 | audit_initialized ? "" : " (after initialization)"); | |
995 | if (audit_initialized) | |
996 | audit_enabled = audit_default; | |
9b41046c | 997 | return 1; |
1da177e4 LT |
998 | } |
999 | ||
1000 | __setup("audit=", audit_enable); | |
1001 | ||
16e1904e CW |
1002 | static void audit_buffer_free(struct audit_buffer *ab) |
1003 | { | |
1004 | unsigned long flags; | |
1005 | ||
8fc6115c CW |
1006 | if (!ab) |
1007 | return; | |
1008 | ||
5ac52f33 CW |
1009 | if (ab->skb) |
1010 | kfree_skb(ab->skb); | |
b7d11258 | 1011 | |
16e1904e | 1012 | spin_lock_irqsave(&audit_freelist_lock, flags); |
5d136a01 | 1013 | if (audit_freelist_count > AUDIT_MAXFREE) |
16e1904e | 1014 | kfree(ab); |
5d136a01 SH |
1015 | else { |
1016 | audit_freelist_count++; | |
16e1904e | 1017 | list_add(&ab->list, &audit_freelist); |
5d136a01 | 1018 | } |
16e1904e CW |
1019 | spin_unlock_irqrestore(&audit_freelist_lock, flags); |
1020 | } | |
1021 | ||
c0404993 | 1022 | static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx, |
dd0fc66f | 1023 | gfp_t gfp_mask, int type) |
16e1904e CW |
1024 | { |
1025 | unsigned long flags; | |
1026 | struct audit_buffer *ab = NULL; | |
c0404993 | 1027 | struct nlmsghdr *nlh; |
16e1904e CW |
1028 | |
1029 | spin_lock_irqsave(&audit_freelist_lock, flags); | |
1030 | if (!list_empty(&audit_freelist)) { | |
1031 | ab = list_entry(audit_freelist.next, | |
1032 | struct audit_buffer, list); | |
1033 | list_del(&ab->list); | |
1034 | --audit_freelist_count; | |
1035 | } | |
1036 | spin_unlock_irqrestore(&audit_freelist_lock, flags); | |
1037 | ||
1038 | if (!ab) { | |
4332bdd3 | 1039 | ab = kmalloc(sizeof(*ab), gfp_mask); |
16e1904e | 1040 | if (!ab) |
8fc6115c | 1041 | goto err; |
16e1904e | 1042 | } |
8fc6115c | 1043 | |
4332bdd3 | 1044 | ab->skb = alloc_skb(AUDIT_BUFSIZ, gfp_mask); |
5ac52f33 | 1045 | if (!ab->skb) |
8fc6115c CW |
1046 | goto err; |
1047 | ||
b7d11258 | 1048 | ab->ctx = ctx; |
9ad9ad38 | 1049 | ab->gfp_mask = gfp_mask; |
c0404993 SG |
1050 | nlh = (struct nlmsghdr *)skb_put(ab->skb, NLMSG_SPACE(0)); |
1051 | nlh->nlmsg_type = type; | |
1052 | nlh->nlmsg_flags = 0; | |
1053 | nlh->nlmsg_pid = 0; | |
1054 | nlh->nlmsg_seq = 0; | |
16e1904e | 1055 | return ab; |
8fc6115c CW |
1056 | err: |
1057 | audit_buffer_free(ab); | |
1058 | return NULL; | |
16e1904e | 1059 | } |
1da177e4 | 1060 | |
b0dd25a8 RD |
1061 | /** |
1062 | * audit_serial - compute a serial number for the audit record | |
1063 | * | |
1064 | * Compute a serial number for the audit record. Audit records are | |
bfb4496e DW |
1065 | * written to user-space as soon as they are generated, so a complete |
1066 | * audit record may be written in several pieces. The timestamp of the | |
1067 | * record and this serial number are used by the user-space tools to | |
1068 | * determine which pieces belong to the same audit record. The | |
1069 | * (timestamp,serial) tuple is unique for each syscall and is live from | |
1070 | * syscall entry to syscall exit. | |
1071 | * | |
bfb4496e DW |
1072 | * NOTE: Another possibility is to store the formatted records off the |
1073 | * audit context (for those records that have a context), and emit them | |
1074 | * all at syscall exit. However, this could delay the reporting of | |
1075 | * significant errors until syscall exit (or never, if the system | |
b0dd25a8 RD |
1076 | * halts). |
1077 | */ | |
bfb4496e DW |
1078 | unsigned int audit_serial(void) |
1079 | { | |
34af946a | 1080 | static DEFINE_SPINLOCK(serial_lock); |
d5b454f2 DW |
1081 | static unsigned int serial = 0; |
1082 | ||
1083 | unsigned long flags; | |
1084 | unsigned int ret; | |
bfb4496e | 1085 | |
d5b454f2 | 1086 | spin_lock_irqsave(&serial_lock, flags); |
bfb4496e | 1087 | do { |
ce625a80 DW |
1088 | ret = ++serial; |
1089 | } while (unlikely(!ret)); | |
d5b454f2 | 1090 | spin_unlock_irqrestore(&serial_lock, flags); |
bfb4496e | 1091 | |
d5b454f2 | 1092 | return ret; |
bfb4496e DW |
1093 | } |
1094 | ||
5600b892 | 1095 | static inline void audit_get_stamp(struct audit_context *ctx, |
bfb4496e DW |
1096 | struct timespec *t, unsigned int *serial) |
1097 | { | |
1098 | if (ctx) | |
1099 | auditsc_get_stamp(ctx, t, serial); | |
1100 | else { | |
1101 | *t = CURRENT_TIME; | |
1102 | *serial = audit_serial(); | |
1103 | } | |
1104 | } | |
1105 | ||
1da177e4 LT |
1106 | /* Obtain an audit buffer. This routine does locking to obtain the |
1107 | * audit buffer, but then no locking is required for calls to | |
1108 | * audit_log_*format. If the tsk is a task that is currently in a | |
1109 | * syscall, then the syscall is marked as auditable and an audit record | |
1110 | * will be written at syscall exit. If there is no associated task, tsk | |
1111 | * should be NULL. */ | |
9ad9ad38 | 1112 | |
b0dd25a8 RD |
1113 | /** |
1114 | * audit_log_start - obtain an audit buffer | |
1115 | * @ctx: audit_context (may be NULL) | |
1116 | * @gfp_mask: type of allocation | |
1117 | * @type: audit message type | |
1118 | * | |
1119 | * Returns audit_buffer pointer on success or NULL on error. | |
1120 | * | |
1121 | * Obtain an audit buffer. This routine does locking to obtain the | |
1122 | * audit buffer, but then no locking is required for calls to | |
1123 | * audit_log_*format. If the task (ctx) is a task that is currently in a | |
1124 | * syscall, then the syscall is marked as auditable and an audit record | |
1125 | * will be written at syscall exit. If there is no associated task, then | |
1126 | * task context (ctx) should be NULL. | |
1127 | */ | |
9796fdd8 | 1128 | struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, |
9ad9ad38 | 1129 | int type) |
1da177e4 LT |
1130 | { |
1131 | struct audit_buffer *ab = NULL; | |
1da177e4 | 1132 | struct timespec t; |
d812ddbb | 1133 | unsigned int serial; |
9ad9ad38 | 1134 | int reserve; |
ac4cec44 | 1135 | unsigned long timeout_start = jiffies; |
1da177e4 LT |
1136 | |
1137 | if (!audit_initialized) | |
1138 | return NULL; | |
1139 | ||
c8edc80c DK |
1140 | if (unlikely(audit_filter_type(type))) |
1141 | return NULL; | |
1142 | ||
9ad9ad38 DW |
1143 | if (gfp_mask & __GFP_WAIT) |
1144 | reserve = 0; | |
1145 | else | |
5600b892 | 1146 | reserve = 5; /* Allow atomic callers to go up to five |
9ad9ad38 DW |
1147 | entries over the normal backlog limit */ |
1148 | ||
1149 | while (audit_backlog_limit | |
1150 | && skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) { | |
ac4cec44 DW |
1151 | if (gfp_mask & __GFP_WAIT && audit_backlog_wait_time |
1152 | && time_before(jiffies, timeout_start + audit_backlog_wait_time)) { | |
1153 | ||
9ad9ad38 DW |
1154 | /* Wait for auditd to drain the queue a little */ |
1155 | DECLARE_WAITQUEUE(wait, current); | |
1156 | set_current_state(TASK_INTERRUPTIBLE); | |
1157 | add_wait_queue(&audit_backlog_wait, &wait); | |
1158 | ||
1159 | if (audit_backlog_limit && | |
1160 | skb_queue_len(&audit_skb_queue) > audit_backlog_limit) | |
ac4cec44 | 1161 | schedule_timeout(timeout_start + audit_backlog_wait_time - jiffies); |
9ad9ad38 DW |
1162 | |
1163 | __set_current_state(TASK_RUNNING); | |
1164 | remove_wait_queue(&audit_backlog_wait, &wait); | |
ac4cec44 | 1165 | continue; |
9ad9ad38 | 1166 | } |
fb19b4c6 DW |
1167 | if (audit_rate_check()) |
1168 | printk(KERN_WARNING | |
1169 | "audit: audit_backlog=%d > " | |
1170 | "audit_backlog_limit=%d\n", | |
1171 | skb_queue_len(&audit_skb_queue), | |
1172 | audit_backlog_limit); | |
1173 | audit_log_lost("backlog limit exceeded"); | |
ac4cec44 DW |
1174 | audit_backlog_wait_time = audit_backlog_wait_overflow; |
1175 | wake_up(&audit_backlog_wait); | |
fb19b4c6 DW |
1176 | return NULL; |
1177 | } | |
1178 | ||
9ad9ad38 | 1179 | ab = audit_buffer_alloc(ctx, gfp_mask, type); |
1da177e4 LT |
1180 | if (!ab) { |
1181 | audit_log_lost("out of memory in audit_log_start"); | |
1182 | return NULL; | |
1183 | } | |
1184 | ||
bfb4496e | 1185 | audit_get_stamp(ab->ctx, &t, &serial); |
197c69c6 | 1186 | |
1da177e4 LT |
1187 | audit_log_format(ab, "audit(%lu.%03lu:%u): ", |
1188 | t.tv_sec, t.tv_nsec/1000000, serial); | |
1189 | return ab; | |
1190 | } | |
1191 | ||
8fc6115c | 1192 | /** |
5ac52f33 | 1193 | * audit_expand - expand skb in the audit buffer |
8fc6115c | 1194 | * @ab: audit_buffer |
b0dd25a8 | 1195 | * @extra: space to add at tail of the skb |
8fc6115c CW |
1196 | * |
1197 | * Returns 0 (no space) on failed expansion, or available space if | |
1198 | * successful. | |
1199 | */ | |
e3b926b4 | 1200 | static inline int audit_expand(struct audit_buffer *ab, int extra) |
8fc6115c | 1201 | { |
5ac52f33 | 1202 | struct sk_buff *skb = ab->skb; |
e3b926b4 | 1203 | int ret = pskb_expand_head(skb, skb_headroom(skb), extra, |
9ad9ad38 | 1204 | ab->gfp_mask); |
5ac52f33 CW |
1205 | if (ret < 0) { |
1206 | audit_log_lost("out of memory in audit_expand"); | |
8fc6115c | 1207 | return 0; |
5ac52f33 CW |
1208 | } |
1209 | return skb_tailroom(skb); | |
8fc6115c | 1210 | } |
1da177e4 | 1211 | |
b0dd25a8 RD |
1212 | /* |
1213 | * Format an audit message into the audit buffer. If there isn't enough | |
1da177e4 LT |
1214 | * room in the audit buffer, more room will be allocated and vsnprint |
1215 | * will be called a second time. Currently, we assume that a printk | |
b0dd25a8 RD |
1216 | * can't format message larger than 1024 bytes, so we don't either. |
1217 | */ | |
1da177e4 LT |
1218 | static void audit_log_vformat(struct audit_buffer *ab, const char *fmt, |
1219 | va_list args) | |
1220 | { | |
1221 | int len, avail; | |
5ac52f33 | 1222 | struct sk_buff *skb; |
eecb0a73 | 1223 | va_list args2; |
1da177e4 LT |
1224 | |
1225 | if (!ab) | |
1226 | return; | |
1227 | ||
5ac52f33 CW |
1228 | BUG_ON(!ab->skb); |
1229 | skb = ab->skb; | |
1230 | avail = skb_tailroom(skb); | |
1231 | if (avail == 0) { | |
e3b926b4 | 1232 | avail = audit_expand(ab, AUDIT_BUFSIZ); |
8fc6115c CW |
1233 | if (!avail) |
1234 | goto out; | |
1da177e4 | 1235 | } |
eecb0a73 | 1236 | va_copy(args2, args); |
27a884dc | 1237 | len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args); |
1da177e4 LT |
1238 | if (len >= avail) { |
1239 | /* The printk buffer is 1024 bytes long, so if we get | |
1240 | * here and AUDIT_BUFSIZ is at least 1024, then we can | |
1241 | * log everything that printk could have logged. */ | |
b0dd25a8 RD |
1242 | avail = audit_expand(ab, |
1243 | max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail)); | |
8fc6115c CW |
1244 | if (!avail) |
1245 | goto out; | |
27a884dc | 1246 | len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2); |
1da177e4 | 1247 | } |
168b7173 SG |
1248 | if (len > 0) |
1249 | skb_put(skb, len); | |
8fc6115c CW |
1250 | out: |
1251 | return; | |
1da177e4 LT |
1252 | } |
1253 | ||
b0dd25a8 RD |
1254 | /** |
1255 | * audit_log_format - format a message into the audit buffer. | |
1256 | * @ab: audit_buffer | |
1257 | * @fmt: format string | |
1258 | * @...: optional parameters matching @fmt string | |
1259 | * | |
1260 | * All the work is done in audit_log_vformat. | |
1261 | */ | |
1da177e4 LT |
1262 | void audit_log_format(struct audit_buffer *ab, const char *fmt, ...) |
1263 | { | |
1264 | va_list args; | |
1265 | ||
1266 | if (!ab) | |
1267 | return; | |
1268 | va_start(args, fmt); | |
1269 | audit_log_vformat(ab, fmt, args); | |
1270 | va_end(args); | |
1271 | } | |
1272 | ||
b0dd25a8 RD |
1273 | /** |
1274 | * audit_log_hex - convert a buffer to hex and append it to the audit skb | |
1275 | * @ab: the audit_buffer | |
1276 | * @buf: buffer to convert to hex | |
1277 | * @len: length of @buf to be converted | |
1278 | * | |
1279 | * No return value; failure to expand is silently ignored. | |
1280 | * | |
1281 | * This function will take the passed buf and convert it into a string of | |
1282 | * ascii hex digits. The new string is placed onto the skb. | |
1283 | */ | |
1284 | void audit_log_hex(struct audit_buffer *ab, const unsigned char *buf, | |
168b7173 | 1285 | size_t len) |
83c7d091 | 1286 | { |
168b7173 SG |
1287 | int i, avail, new_len; |
1288 | unsigned char *ptr; | |
1289 | struct sk_buff *skb; | |
1290 | static const unsigned char *hex = "0123456789ABCDEF"; | |
1291 | ||
8ef2d304 AG |
1292 | if (!ab) |
1293 | return; | |
1294 | ||
168b7173 SG |
1295 | BUG_ON(!ab->skb); |
1296 | skb = ab->skb; | |
1297 | avail = skb_tailroom(skb); | |
1298 | new_len = len<<1; | |
1299 | if (new_len >= avail) { | |
1300 | /* Round the buffer request up to the next multiple */ | |
1301 | new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1); | |
1302 | avail = audit_expand(ab, new_len); | |
1303 | if (!avail) | |
1304 | return; | |
1305 | } | |
83c7d091 | 1306 | |
27a884dc | 1307 | ptr = skb_tail_pointer(skb); |
168b7173 SG |
1308 | for (i=0; i<len; i++) { |
1309 | *ptr++ = hex[(buf[i] & 0xF0)>>4]; /* Upper nibble */ | |
1310 | *ptr++ = hex[buf[i] & 0x0F]; /* Lower nibble */ | |
1311 | } | |
1312 | *ptr = 0; | |
1313 | skb_put(skb, len << 1); /* new string is twice the old string */ | |
83c7d091 | 1314 | } |
1315 | ||
9c937dcc AG |
1316 | /* |
1317 | * Format a string of no more than slen characters into the audit buffer, | |
1318 | * enclosed in quote marks. | |
1319 | */ | |
1320 | static void audit_log_n_string(struct audit_buffer *ab, size_t slen, | |
1321 | const char *string) | |
1322 | { | |
1323 | int avail, new_len; | |
1324 | unsigned char *ptr; | |
1325 | struct sk_buff *skb; | |
1326 | ||
8ef2d304 AG |
1327 | if (!ab) |
1328 | return; | |
1329 | ||
9c937dcc AG |
1330 | BUG_ON(!ab->skb); |
1331 | skb = ab->skb; | |
1332 | avail = skb_tailroom(skb); | |
1333 | new_len = slen + 3; /* enclosing quotes + null terminator */ | |
1334 | if (new_len > avail) { | |
1335 | avail = audit_expand(ab, new_len); | |
1336 | if (!avail) | |
1337 | return; | |
1338 | } | |
27a884dc | 1339 | ptr = skb_tail_pointer(skb); |
9c937dcc AG |
1340 | *ptr++ = '"'; |
1341 | memcpy(ptr, string, slen); | |
1342 | ptr += slen; | |
1343 | *ptr++ = '"'; | |
1344 | *ptr = 0; | |
1345 | skb_put(skb, slen + 2); /* don't include null terminator */ | |
1346 | } | |
1347 | ||
b0dd25a8 | 1348 | /** |
522ed776 | 1349 | * audit_log_n_untrustedstring - log a string that may contain random characters |
b0dd25a8 | 1350 | * @ab: audit_buffer |
9c937dcc | 1351 | * @len: lenth of string (not including trailing null) |
b0dd25a8 RD |
1352 | * @string: string to be logged |
1353 | * | |
1354 | * This code will escape a string that is passed to it if the string | |
1355 | * contains a control character, unprintable character, double quote mark, | |
168b7173 | 1356 | * or a space. Unescaped strings will start and end with a double quote mark. |
b0dd25a8 | 1357 | * Strings that are escaped are printed in hex (2 digits per char). |
9c937dcc AG |
1358 | * |
1359 | * The caller specifies the number of characters in the string to log, which may | |
1360 | * or may not be the entire string. | |
b0dd25a8 | 1361 | */ |
9c937dcc AG |
1362 | const char *audit_log_n_untrustedstring(struct audit_buffer *ab, size_t len, |
1363 | const char *string) | |
83c7d091 | 1364 | { |
522ed776 | 1365 | const unsigned char *p; |
83c7d091 | 1366 | |
522ed776 | 1367 | for (p = string; p < (const unsigned char *)string + len && *p; p++) { |
168b7173 | 1368 | if (*p == '"' || *p < 0x21 || *p > 0x7f) { |
473ae30b AV |
1369 | audit_log_hex(ab, string, len); |
1370 | return string + len + 1; | |
83c7d091 | 1371 | } |
83c7d091 | 1372 | } |
9c937dcc | 1373 | audit_log_n_string(ab, len, string); |
473ae30b | 1374 | return p + 1; |
83c7d091 | 1375 | } |
1376 | ||
9c937dcc | 1377 | /** |
522ed776 | 1378 | * audit_log_untrustedstring - log a string that may contain random characters |
9c937dcc AG |
1379 | * @ab: audit_buffer |
1380 | * @string: string to be logged | |
1381 | * | |
522ed776 | 1382 | * Same as audit_log_n_untrustedstring(), except that strlen is used to |
9c937dcc AG |
1383 | * determine string length. |
1384 | */ | |
1385 | const char *audit_log_untrustedstring(struct audit_buffer *ab, const char *string) | |
1386 | { | |
1387 | return audit_log_n_untrustedstring(ab, strlen(string), string); | |
1388 | } | |
1389 | ||
168b7173 | 1390 | /* This is a helper-function to print the escaped d_path */ |
1da177e4 LT |
1391 | void audit_log_d_path(struct audit_buffer *ab, const char *prefix, |
1392 | struct dentry *dentry, struct vfsmount *vfsmnt) | |
1393 | { | |
168b7173 | 1394 | char *p, *path; |
1da177e4 | 1395 | |
8fc6115c CW |
1396 | if (prefix) |
1397 | audit_log_format(ab, " %s", prefix); | |
1da177e4 | 1398 | |
168b7173 | 1399 | /* We will allow 11 spaces for ' (deleted)' to be appended */ |
9ad9ad38 | 1400 | path = kmalloc(PATH_MAX+11, ab->gfp_mask); |
168b7173 SG |
1401 | if (!path) { |
1402 | audit_log_format(ab, "<no memory>"); | |
1403 | return; | |
1da177e4 | 1404 | } |
168b7173 SG |
1405 | p = d_path(dentry, vfsmnt, path, PATH_MAX+11); |
1406 | if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */ | |
1407 | /* FIXME: can we save some information here? */ | |
1408 | audit_log_format(ab, "<too long>"); | |
5600b892 | 1409 | } else |
168b7173 SG |
1410 | audit_log_untrustedstring(ab, p); |
1411 | kfree(path); | |
1da177e4 LT |
1412 | } |
1413 | ||
b0dd25a8 RD |
1414 | /** |
1415 | * audit_log_end - end one audit record | |
1416 | * @ab: the audit_buffer | |
1417 | * | |
1418 | * The netlink_* functions cannot be called inside an irq context, so | |
1419 | * the audit buffer is placed on a queue and a tasklet is scheduled to | |
1da177e4 | 1420 | * remove them from the queue outside the irq context. May be called in |
b0dd25a8 RD |
1421 | * any context. |
1422 | */ | |
b7d11258 | 1423 | void audit_log_end(struct audit_buffer *ab) |
1da177e4 | 1424 | { |
1da177e4 LT |
1425 | if (!ab) |
1426 | return; | |
1427 | if (!audit_rate_check()) { | |
1428 | audit_log_lost("rate limit exceeded"); | |
1429 | } else { | |
b7d11258 | 1430 | if (audit_pid) { |
b529ccf2 | 1431 | struct nlmsghdr *nlh = nlmsg_hdr(ab->skb); |
b7d11258 DW |
1432 | nlh->nlmsg_len = ab->skb->len - NLMSG_SPACE(0); |
1433 | skb_queue_tail(&audit_skb_queue, ab->skb); | |
1434 | ab->skb = NULL; | |
1435 | wake_up_interruptible(&kauditd_wait); | |
1436 | } else { | |
e1b09eba | 1437 | printk(KERN_NOTICE "%s\n", ab->skb->data + NLMSG_SPACE(0)); |
b7d11258 | 1438 | } |
1da177e4 | 1439 | } |
16e1904e | 1440 | audit_buffer_free(ab); |
1da177e4 LT |
1441 | } |
1442 | ||
b0dd25a8 RD |
1443 | /** |
1444 | * audit_log - Log an audit record | |
1445 | * @ctx: audit context | |
1446 | * @gfp_mask: type of allocation | |
1447 | * @type: audit message type | |
1448 | * @fmt: format string to use | |
1449 | * @...: variable parameters matching the format string | |
1450 | * | |
1451 | * This is a convenience function that calls audit_log_start, | |
1452 | * audit_log_vformat, and audit_log_end. It may be called | |
1453 | * in any context. | |
1454 | */ | |
5600b892 | 1455 | void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type, |
9ad9ad38 | 1456 | const char *fmt, ...) |
1da177e4 LT |
1457 | { |
1458 | struct audit_buffer *ab; | |
1459 | va_list args; | |
1460 | ||
9ad9ad38 | 1461 | ab = audit_log_start(ctx, gfp_mask, type); |
1da177e4 LT |
1462 | if (ab) { |
1463 | va_start(args, fmt); | |
1464 | audit_log_vformat(ab, fmt, args); | |
1465 | va_end(args); | |
1466 | audit_log_end(ab); | |
1467 | } | |
1468 | } | |
bf45da97 | 1469 | |
1470 | EXPORT_SYMBOL(audit_log_start); | |
1471 | EXPORT_SYMBOL(audit_log_end); | |
1472 | EXPORT_SYMBOL(audit_log_format); | |
1473 | EXPORT_SYMBOL(audit_log); |