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Commit | Line | Data |
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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 | ||
1a6b9f23 EP |
69 | #define AUDIT_OFF 0 |
70 | #define AUDIT_ON 1 | |
71 | #define AUDIT_LOCKED 2 | |
1da177e4 | 72 | int audit_enabled; |
b593d384 | 73 | int audit_ever_enabled; |
1da177e4 LT |
74 | |
75 | /* Default state when kernel boots without any parameters. */ | |
76 | static int audit_default; | |
77 | ||
78 | /* If auditing cannot proceed, audit_failure selects what happens. */ | |
79 | static int audit_failure = AUDIT_FAIL_PRINTK; | |
80 | ||
81 | /* If audit records are to be written to the netlink socket, audit_pid | |
82 | * contains the (non-zero) pid. */ | |
c2f0c7c3 | 83 | int audit_pid; |
1da177e4 | 84 | |
b0dd25a8 | 85 | /* If audit_rate_limit is non-zero, limit the rate of sending audit records |
1da177e4 LT |
86 | * to that number per second. This prevents DoS attacks, but results in |
87 | * audit records being dropped. */ | |
88 | static int audit_rate_limit; | |
89 | ||
90 | /* Number of outstanding audit_buffers allowed. */ | |
91 | static int audit_backlog_limit = 64; | |
ac4cec44 DW |
92 | static int audit_backlog_wait_time = 60 * HZ; |
93 | static int audit_backlog_wait_overflow = 0; | |
1da177e4 | 94 | |
c2f0c7c3 SG |
95 | /* The identity of the user shutting down the audit system. */ |
96 | uid_t audit_sig_uid = -1; | |
97 | pid_t audit_sig_pid = -1; | |
e1396065 | 98 | u32 audit_sig_sid = 0; |
c2f0c7c3 | 99 | |
1da177e4 LT |
100 | /* Records can be lost in several ways: |
101 | 0) [suppressed in audit_alloc] | |
102 | 1) out of memory in audit_log_start [kmalloc of struct audit_buffer] | |
103 | 2) out of memory in audit_log_move [alloc_skb] | |
104 | 3) suppressed due to audit_rate_limit | |
105 | 4) suppressed due to audit_backlog_limit | |
106 | */ | |
107 | static atomic_t audit_lost = ATOMIC_INIT(0); | |
108 | ||
109 | /* The netlink socket. */ | |
110 | static struct sock *audit_sock; | |
111 | ||
f368c07d AG |
112 | /* Inotify handle. */ |
113 | struct inotify_handle *audit_ih; | |
114 | ||
115 | /* Hash for inode-based rules */ | |
116 | struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS]; | |
117 | ||
b7d11258 | 118 | /* The audit_freelist is a list of pre-allocated audit buffers (if more |
1da177e4 LT |
119 | * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of |
120 | * being placed on the freelist). */ | |
1da177e4 | 121 | static DEFINE_SPINLOCK(audit_freelist_lock); |
b0dd25a8 | 122 | static int audit_freelist_count; |
1da177e4 LT |
123 | static LIST_HEAD(audit_freelist); |
124 | ||
b7d11258 DW |
125 | static struct sk_buff_head audit_skb_queue; |
126 | static struct task_struct *kauditd_task; | |
127 | static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait); | |
9ad9ad38 | 128 | static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait); |
1da177e4 | 129 | |
f368c07d AG |
130 | /* Serialize requests from userspace. */ |
131 | static DEFINE_MUTEX(audit_cmd_mutex); | |
1da177e4 LT |
132 | |
133 | /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting | |
134 | * audit records. Since printk uses a 1024 byte buffer, this buffer | |
135 | * should be at least that large. */ | |
136 | #define AUDIT_BUFSIZ 1024 | |
137 | ||
138 | /* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the | |
139 | * audit_freelist. Doing so eliminates many kmalloc/kfree calls. */ | |
140 | #define AUDIT_MAXFREE (2*NR_CPUS) | |
141 | ||
142 | /* The audit_buffer is used when formatting an audit record. The caller | |
143 | * locks briefly to get the record off the freelist or to allocate the | |
144 | * buffer, and locks briefly to send the buffer to the netlink layer or | |
145 | * to place it on a transmit queue. Multiple audit_buffers can be in | |
146 | * use simultaneously. */ | |
147 | struct audit_buffer { | |
148 | struct list_head list; | |
8fc6115c | 149 | struct sk_buff *skb; /* formatted skb ready to send */ |
1da177e4 | 150 | struct audit_context *ctx; /* NULL or associated context */ |
9796fdd8 | 151 | gfp_t gfp_mask; |
1da177e4 LT |
152 | }; |
153 | ||
c0404993 SG |
154 | static void audit_set_pid(struct audit_buffer *ab, pid_t pid) |
155 | { | |
50397bd1 EP |
156 | if (ab) { |
157 | struct nlmsghdr *nlh = nlmsg_hdr(ab->skb); | |
158 | nlh->nlmsg_pid = pid; | |
159 | } | |
c0404993 SG |
160 | } |
161 | ||
8c8570fb | 162 | void audit_panic(const char *message) |
1da177e4 LT |
163 | { |
164 | switch (audit_failure) | |
165 | { | |
166 | case AUDIT_FAIL_SILENT: | |
167 | break; | |
168 | case AUDIT_FAIL_PRINTK: | |
320f1b1e EP |
169 | if (printk_ratelimit()) |
170 | printk(KERN_ERR "audit: %s\n", message); | |
1da177e4 LT |
171 | break; |
172 | case AUDIT_FAIL_PANIC: | |
b29ee87e EP |
173 | /* test audit_pid since printk is always losey, why bother? */ |
174 | if (audit_pid) | |
175 | panic("audit: %s\n", message); | |
1da177e4 LT |
176 | break; |
177 | } | |
178 | } | |
179 | ||
180 | static inline int audit_rate_check(void) | |
181 | { | |
182 | static unsigned long last_check = 0; | |
183 | static int messages = 0; | |
184 | static DEFINE_SPINLOCK(lock); | |
185 | unsigned long flags; | |
186 | unsigned long now; | |
187 | unsigned long elapsed; | |
188 | int retval = 0; | |
189 | ||
190 | if (!audit_rate_limit) return 1; | |
191 | ||
192 | spin_lock_irqsave(&lock, flags); | |
193 | if (++messages < audit_rate_limit) { | |
194 | retval = 1; | |
195 | } else { | |
196 | now = jiffies; | |
197 | elapsed = now - last_check; | |
198 | if (elapsed > HZ) { | |
199 | last_check = now; | |
200 | messages = 0; | |
201 | retval = 1; | |
202 | } | |
203 | } | |
204 | spin_unlock_irqrestore(&lock, flags); | |
205 | ||
206 | return retval; | |
207 | } | |
208 | ||
b0dd25a8 RD |
209 | /** |
210 | * audit_log_lost - conditionally log lost audit message event | |
211 | * @message: the message stating reason for lost audit message | |
212 | * | |
213 | * Emit at least 1 message per second, even if audit_rate_check is | |
214 | * throttling. | |
215 | * Always increment the lost messages counter. | |
216 | */ | |
1da177e4 LT |
217 | void audit_log_lost(const char *message) |
218 | { | |
219 | static unsigned long last_msg = 0; | |
220 | static DEFINE_SPINLOCK(lock); | |
221 | unsigned long flags; | |
222 | unsigned long now; | |
223 | int print; | |
224 | ||
225 | atomic_inc(&audit_lost); | |
226 | ||
227 | print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit); | |
228 | ||
229 | if (!print) { | |
230 | spin_lock_irqsave(&lock, flags); | |
231 | now = jiffies; | |
232 | if (now - last_msg > HZ) { | |
233 | print = 1; | |
234 | last_msg = now; | |
235 | } | |
236 | spin_unlock_irqrestore(&lock, flags); | |
237 | } | |
238 | ||
239 | if (print) { | |
320f1b1e EP |
240 | if (printk_ratelimit()) |
241 | printk(KERN_WARNING | |
242 | "audit: audit_lost=%d audit_rate_limit=%d " | |
243 | "audit_backlog_limit=%d\n", | |
244 | atomic_read(&audit_lost), | |
245 | audit_rate_limit, | |
246 | audit_backlog_limit); | |
1da177e4 LT |
247 | audit_panic(message); |
248 | } | |
1da177e4 LT |
249 | } |
250 | ||
1a6b9f23 EP |
251 | static int audit_log_config_change(char *function_name, int new, int old, |
252 | uid_t loginuid, u32 sid, int allow_changes) | |
1da177e4 | 253 | { |
1a6b9f23 EP |
254 | struct audit_buffer *ab; |
255 | int rc = 0; | |
ce29b682 | 256 | |
1a6b9f23 EP |
257 | ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE); |
258 | audit_log_format(ab, "%s=%d old=%d by auid=%u", function_name, new, | |
259 | old, loginuid); | |
ce29b682 SG |
260 | if (sid) { |
261 | char *ctx = NULL; | |
262 | u32 len; | |
1a6b9f23 EP |
263 | |
264 | rc = selinux_sid_to_string(sid, &ctx, &len); | |
265 | if (rc) { | |
266 | audit_log_format(ab, " sid=%u", sid); | |
267 | allow_changes = 0; /* Something weird, deny request */ | |
268 | } else { | |
269 | audit_log_format(ab, " subj=%s", ctx); | |
6a01b07f | 270 | kfree(ctx); |
1a6b9f23 | 271 | } |
6a01b07f | 272 | } |
1a6b9f23 EP |
273 | audit_log_format(ab, " res=%d", allow_changes); |
274 | audit_log_end(ab); | |
6a01b07f | 275 | return rc; |
1da177e4 LT |
276 | } |
277 | ||
1a6b9f23 EP |
278 | static int audit_do_config_change(char *function_name, int *to_change, |
279 | int new, uid_t loginuid, u32 sid) | |
1da177e4 | 280 | { |
1a6b9f23 | 281 | int allow_changes, rc = 0, old = *to_change; |
6a01b07f SG |
282 | |
283 | /* check if we are locked */ | |
1a6b9f23 EP |
284 | if (audit_enabled == AUDIT_LOCKED) |
285 | allow_changes = 0; | |
6a01b07f | 286 | else |
1a6b9f23 | 287 | allow_changes = 1; |
ce29b682 | 288 | |
1a6b9f23 EP |
289 | if (audit_enabled != AUDIT_OFF) { |
290 | rc = audit_log_config_change(function_name, new, old, | |
291 | loginuid, sid, allow_changes); | |
292 | if (rc) | |
293 | allow_changes = 0; | |
6a01b07f | 294 | } |
6a01b07f SG |
295 | |
296 | /* If we are allowed, make the change */ | |
1a6b9f23 EP |
297 | if (allow_changes == 1) |
298 | *to_change = new; | |
6a01b07f SG |
299 | /* Not allowed, update reason */ |
300 | else if (rc == 0) | |
301 | rc = -EPERM; | |
302 | return rc; | |
1da177e4 LT |
303 | } |
304 | ||
1a6b9f23 | 305 | static int audit_set_rate_limit(int limit, uid_t loginuid, u32 sid) |
1da177e4 | 306 | { |
1a6b9f23 EP |
307 | return audit_do_config_change("audit_rate_limit", &audit_rate_limit, |
308 | limit, loginuid, sid); | |
309 | } | |
ce29b682 | 310 | |
1a6b9f23 EP |
311 | static int audit_set_backlog_limit(int limit, uid_t loginuid, u32 sid) |
312 | { | |
313 | return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, | |
314 | limit, loginuid, sid); | |
315 | } | |
6a01b07f | 316 | |
1a6b9f23 EP |
317 | static int audit_set_enabled(int state, uid_t loginuid, u32 sid) |
318 | { | |
b593d384 | 319 | int rc; |
1a6b9f23 EP |
320 | if (state < AUDIT_OFF || state > AUDIT_LOCKED) |
321 | return -EINVAL; | |
6a01b07f | 322 | |
b593d384 EP |
323 | rc = audit_do_config_change("audit_enabled", &audit_enabled, state, |
324 | loginuid, sid); | |
325 | ||
326 | if (!rc) | |
327 | audit_ever_enabled |= !!state; | |
328 | ||
329 | return rc; | |
1da177e4 LT |
330 | } |
331 | ||
ce29b682 | 332 | static int audit_set_failure(int state, uid_t loginuid, u32 sid) |
1da177e4 | 333 | { |
1da177e4 LT |
334 | if (state != AUDIT_FAIL_SILENT |
335 | && state != AUDIT_FAIL_PRINTK | |
336 | && state != AUDIT_FAIL_PANIC) | |
337 | return -EINVAL; | |
ce29b682 | 338 | |
1a6b9f23 EP |
339 | return audit_do_config_change("audit_failure", &audit_failure, state, |
340 | loginuid, sid); | |
1da177e4 LT |
341 | } |
342 | ||
97a41e26 | 343 | static int kauditd_thread(void *dummy) |
b7d11258 DW |
344 | { |
345 | struct sk_buff *skb; | |
346 | ||
83144186 | 347 | set_freezable(); |
4899b8b1 | 348 | while (!kthread_should_stop()) { |
b7d11258 | 349 | skb = skb_dequeue(&audit_skb_queue); |
9ad9ad38 | 350 | wake_up(&audit_backlog_wait); |
b7d11258 DW |
351 | if (skb) { |
352 | if (audit_pid) { | |
353 | int err = netlink_unicast(audit_sock, skb, audit_pid, 0); | |
354 | if (err < 0) { | |
355 | BUG_ON(err != -ECONNREFUSED); /* Shoudn't happen */ | |
356 | printk(KERN_ERR "audit: *NO* daemon at audit_pid=%d\n", audit_pid); | |
b29ee87e | 357 | audit_log_lost("auditd dissapeared\n"); |
b7d11258 DW |
358 | audit_pid = 0; |
359 | } | |
360 | } else { | |
320f1b1e EP |
361 | if (printk_ratelimit()) |
362 | printk(KERN_NOTICE "%s\n", skb->data + | |
363 | NLMSG_SPACE(0)); | |
364 | else | |
365 | audit_log_lost("printk limit exceeded\n"); | |
b7d11258 DW |
366 | kfree_skb(skb); |
367 | } | |
368 | } else { | |
369 | DECLARE_WAITQUEUE(wait, current); | |
370 | set_current_state(TASK_INTERRUPTIBLE); | |
371 | add_wait_queue(&kauditd_wait, &wait); | |
372 | ||
7a4ae749 PO |
373 | if (!skb_queue_len(&audit_skb_queue)) { |
374 | try_to_freeze(); | |
b7d11258 | 375 | schedule(); |
7a4ae749 | 376 | } |
b7d11258 DW |
377 | |
378 | __set_current_state(TASK_RUNNING); | |
379 | remove_wait_queue(&kauditd_wait, &wait); | |
380 | } | |
381 | } | |
4899b8b1 | 382 | return 0; |
b7d11258 DW |
383 | } |
384 | ||
522ed776 MT |
385 | static int audit_prepare_user_tty(pid_t pid, uid_t loginuid) |
386 | { | |
387 | struct task_struct *tsk; | |
388 | int err; | |
389 | ||
390 | read_lock(&tasklist_lock); | |
391 | tsk = find_task_by_pid(pid); | |
392 | err = -ESRCH; | |
393 | if (!tsk) | |
394 | goto out; | |
395 | err = 0; | |
396 | ||
397 | spin_lock_irq(&tsk->sighand->siglock); | |
398 | if (!tsk->signal->audit_tty) | |
399 | err = -EPERM; | |
400 | spin_unlock_irq(&tsk->sighand->siglock); | |
401 | if (err) | |
402 | goto out; | |
403 | ||
404 | tty_audit_push_task(tsk, loginuid); | |
405 | out: | |
406 | read_unlock(&tasklist_lock); | |
407 | return err; | |
408 | } | |
409 | ||
9044e6bc AV |
410 | int audit_send_list(void *_dest) |
411 | { | |
412 | struct audit_netlink_list *dest = _dest; | |
413 | int pid = dest->pid; | |
414 | struct sk_buff *skb; | |
415 | ||
416 | /* wait for parent to finish and send an ACK */ | |
f368c07d AG |
417 | mutex_lock(&audit_cmd_mutex); |
418 | mutex_unlock(&audit_cmd_mutex); | |
9044e6bc AV |
419 | |
420 | while ((skb = __skb_dequeue(&dest->q)) != NULL) | |
421 | netlink_unicast(audit_sock, skb, pid, 0); | |
422 | ||
423 | kfree(dest); | |
424 | ||
425 | return 0; | |
426 | } | |
427 | ||
74c3cbe3 AV |
428 | #ifdef CONFIG_AUDIT_TREE |
429 | static int prune_tree_thread(void *unused) | |
430 | { | |
431 | mutex_lock(&audit_cmd_mutex); | |
432 | audit_prune_trees(); | |
433 | mutex_unlock(&audit_cmd_mutex); | |
434 | return 0; | |
435 | } | |
436 | ||
437 | void audit_schedule_prune(void) | |
438 | { | |
439 | kthread_run(prune_tree_thread, NULL, "audit_prune_tree"); | |
440 | } | |
441 | #endif | |
442 | ||
9044e6bc AV |
443 | struct sk_buff *audit_make_reply(int pid, int seq, int type, int done, |
444 | int multi, void *payload, int size) | |
445 | { | |
446 | struct sk_buff *skb; | |
447 | struct nlmsghdr *nlh; | |
448 | int len = NLMSG_SPACE(size); | |
449 | void *data; | |
450 | int flags = multi ? NLM_F_MULTI : 0; | |
451 | int t = done ? NLMSG_DONE : type; | |
452 | ||
453 | skb = alloc_skb(len, GFP_KERNEL); | |
454 | if (!skb) | |
455 | return NULL; | |
456 | ||
457 | nlh = NLMSG_PUT(skb, pid, seq, t, size); | |
458 | nlh->nlmsg_flags = flags; | |
459 | data = NLMSG_DATA(nlh); | |
460 | memcpy(data, payload, size); | |
461 | return skb; | |
462 | ||
463 | nlmsg_failure: /* Used by NLMSG_PUT */ | |
464 | if (skb) | |
465 | kfree_skb(skb); | |
466 | return NULL; | |
467 | } | |
468 | ||
b0dd25a8 RD |
469 | /** |
470 | * audit_send_reply - send an audit reply message via netlink | |
471 | * @pid: process id to send reply to | |
472 | * @seq: sequence number | |
473 | * @type: audit message type | |
474 | * @done: done (last) flag | |
475 | * @multi: multi-part message flag | |
476 | * @payload: payload data | |
477 | * @size: payload size | |
478 | * | |
479 | * Allocates an skb, builds the netlink message, and sends it to the pid. | |
480 | * No failure notifications. | |
481 | */ | |
1da177e4 LT |
482 | void audit_send_reply(int pid, int seq, int type, int done, int multi, |
483 | void *payload, int size) | |
484 | { | |
485 | struct sk_buff *skb; | |
9044e6bc | 486 | skb = audit_make_reply(pid, seq, type, done, multi, payload, size); |
1da177e4 | 487 | if (!skb) |
b7d11258 | 488 | return; |
b7d11258 DW |
489 | /* Ignore failure. It'll only happen if the sender goes away, |
490 | because our timeout is set to infinite. */ | |
491 | netlink_unicast(audit_sock, skb, pid, 0); | |
1da177e4 | 492 | return; |
1da177e4 LT |
493 | } |
494 | ||
495 | /* | |
496 | * Check for appropriate CAP_AUDIT_ capabilities on incoming audit | |
497 | * control messages. | |
498 | */ | |
c7bdb545 | 499 | static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type) |
1da177e4 LT |
500 | { |
501 | int err = 0; | |
502 | ||
503 | switch (msg_type) { | |
504 | case AUDIT_GET: | |
505 | case AUDIT_LIST: | |
93315ed6 | 506 | case AUDIT_LIST_RULES: |
1da177e4 LT |
507 | case AUDIT_SET: |
508 | case AUDIT_ADD: | |
93315ed6 | 509 | case AUDIT_ADD_RULE: |
1da177e4 | 510 | case AUDIT_DEL: |
93315ed6 | 511 | case AUDIT_DEL_RULE: |
c2f0c7c3 | 512 | case AUDIT_SIGNAL_INFO: |
522ed776 MT |
513 | case AUDIT_TTY_GET: |
514 | case AUDIT_TTY_SET: | |
74c3cbe3 AV |
515 | case AUDIT_TRIM: |
516 | case AUDIT_MAKE_EQUIV: | |
c7bdb545 | 517 | if (security_netlink_recv(skb, CAP_AUDIT_CONTROL)) |
1da177e4 LT |
518 | err = -EPERM; |
519 | break; | |
05474106 | 520 | case AUDIT_USER: |
039b6b3e RD |
521 | case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG: |
522 | case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2: | |
c7bdb545 | 523 | if (security_netlink_recv(skb, CAP_AUDIT_WRITE)) |
1da177e4 LT |
524 | err = -EPERM; |
525 | break; | |
526 | default: /* bad msg */ | |
527 | err = -EINVAL; | |
528 | } | |
529 | ||
530 | return err; | |
531 | } | |
532 | ||
50397bd1 EP |
533 | static int audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type, |
534 | u32 pid, u32 uid, uid_t auid, u32 sid) | |
535 | { | |
536 | int rc = 0; | |
537 | char *ctx = NULL; | |
538 | u32 len; | |
539 | ||
540 | if (!audit_enabled) { | |
541 | *ab = NULL; | |
542 | return rc; | |
543 | } | |
544 | ||
545 | *ab = audit_log_start(NULL, GFP_KERNEL, msg_type); | |
546 | audit_log_format(*ab, "user pid=%d uid=%u auid=%u", | |
547 | pid, uid, auid); | |
548 | if (sid) { | |
549 | rc = selinux_sid_to_string(sid, &ctx, &len); | |
550 | if (rc) | |
551 | audit_log_format(*ab, " ssid=%u", sid); | |
552 | else | |
553 | audit_log_format(*ab, " subj=%s", ctx); | |
554 | kfree(ctx); | |
555 | } | |
556 | ||
557 | return rc; | |
558 | } | |
559 | ||
1da177e4 LT |
560 | static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) |
561 | { | |
e7c34970 | 562 | u32 uid, pid, seq, sid; |
1da177e4 LT |
563 | void *data; |
564 | struct audit_status *status_get, status_set; | |
565 | int err; | |
c0404993 | 566 | struct audit_buffer *ab; |
1da177e4 | 567 | u16 msg_type = nlh->nlmsg_type; |
c94c257c | 568 | uid_t loginuid; /* loginuid of sender */ |
e1396065 | 569 | struct audit_sig_info *sig_data; |
50397bd1 | 570 | char *ctx = NULL; |
e1396065 | 571 | u32 len; |
1da177e4 | 572 | |
c7bdb545 | 573 | err = audit_netlink_ok(skb, msg_type); |
1da177e4 LT |
574 | if (err) |
575 | return err; | |
576 | ||
b0dd25a8 RD |
577 | /* As soon as there's any sign of userspace auditd, |
578 | * start kauditd to talk to it */ | |
b7d11258 DW |
579 | if (!kauditd_task) |
580 | kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd"); | |
581 | if (IS_ERR(kauditd_task)) { | |
582 | err = PTR_ERR(kauditd_task); | |
583 | kauditd_task = NULL; | |
584 | return err; | |
585 | } | |
586 | ||
1da177e4 LT |
587 | pid = NETLINK_CREDS(skb)->pid; |
588 | uid = NETLINK_CREDS(skb)->uid; | |
c94c257c | 589 | loginuid = NETLINK_CB(skb).loginuid; |
e7c34970 | 590 | sid = NETLINK_CB(skb).sid; |
1da177e4 LT |
591 | seq = nlh->nlmsg_seq; |
592 | data = NLMSG_DATA(nlh); | |
593 | ||
594 | switch (msg_type) { | |
595 | case AUDIT_GET: | |
596 | status_set.enabled = audit_enabled; | |
597 | status_set.failure = audit_failure; | |
598 | status_set.pid = audit_pid; | |
599 | status_set.rate_limit = audit_rate_limit; | |
600 | status_set.backlog_limit = audit_backlog_limit; | |
601 | status_set.lost = atomic_read(&audit_lost); | |
b7d11258 | 602 | status_set.backlog = skb_queue_len(&audit_skb_queue); |
1da177e4 LT |
603 | audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_GET, 0, 0, |
604 | &status_set, sizeof(status_set)); | |
605 | break; | |
606 | case AUDIT_SET: | |
607 | if (nlh->nlmsg_len < sizeof(struct audit_status)) | |
608 | return -EINVAL; | |
609 | status_get = (struct audit_status *)data; | |
610 | if (status_get->mask & AUDIT_STATUS_ENABLED) { | |
ce29b682 SG |
611 | err = audit_set_enabled(status_get->enabled, |
612 | loginuid, sid); | |
1da177e4 LT |
613 | if (err < 0) return err; |
614 | } | |
615 | if (status_get->mask & AUDIT_STATUS_FAILURE) { | |
ce29b682 SG |
616 | err = audit_set_failure(status_get->failure, |
617 | loginuid, sid); | |
1da177e4 LT |
618 | if (err < 0) return err; |
619 | } | |
620 | if (status_get->mask & AUDIT_STATUS_PID) { | |
1a6b9f23 EP |
621 | int new_pid = status_get->pid; |
622 | ||
623 | if (audit_enabled != AUDIT_OFF) | |
624 | audit_log_config_change("audit_pid", new_pid, | |
625 | audit_pid, loginuid, | |
626 | sid, 1); | |
627 | ||
628 | audit_pid = new_pid; | |
1da177e4 LT |
629 | } |
630 | if (status_get->mask & AUDIT_STATUS_RATE_LIMIT) | |
5d136a01 | 631 | err = audit_set_rate_limit(status_get->rate_limit, |
ce29b682 | 632 | loginuid, sid); |
1da177e4 | 633 | if (status_get->mask & AUDIT_STATUS_BACKLOG_LIMIT) |
5d136a01 | 634 | err = audit_set_backlog_limit(status_get->backlog_limit, |
ce29b682 | 635 | loginuid, sid); |
1da177e4 | 636 | break; |
05474106 | 637 | case AUDIT_USER: |
039b6b3e RD |
638 | case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG: |
639 | case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2: | |
4a4cd633 DW |
640 | if (!audit_enabled && msg_type != AUDIT_USER_AVC) |
641 | return 0; | |
642 | ||
5bb289b5 | 643 | err = audit_filter_user(&NETLINK_CB(skb), msg_type); |
4a4cd633 DW |
644 | if (err == 1) { |
645 | err = 0; | |
522ed776 MT |
646 | if (msg_type == AUDIT_USER_TTY) { |
647 | err = audit_prepare_user_tty(pid, loginuid); | |
648 | if (err) | |
649 | break; | |
650 | } | |
50397bd1 EP |
651 | audit_log_common_recv_msg(&ab, msg_type, pid, uid, |
652 | loginuid, sid); | |
653 | ||
654 | if (msg_type != AUDIT_USER_TTY) | |
655 | audit_log_format(ab, " msg='%.1024s'", | |
656 | (char *)data); | |
657 | else { | |
658 | int size; | |
659 | ||
660 | audit_log_format(ab, " msg="); | |
661 | size = nlmsg_len(nlh); | |
662 | audit_log_n_untrustedstring(ab, size, | |
663 | data); | |
4a4cd633 | 664 | } |
50397bd1 EP |
665 | audit_set_pid(ab, pid); |
666 | audit_log_end(ab); | |
0f45aa18 | 667 | } |
1da177e4 LT |
668 | break; |
669 | case AUDIT_ADD: | |
670 | case AUDIT_DEL: | |
93315ed6 | 671 | if (nlmsg_len(nlh) < sizeof(struct audit_rule)) |
1da177e4 | 672 | return -EINVAL; |
1a6b9f23 | 673 | if (audit_enabled == AUDIT_LOCKED) { |
50397bd1 EP |
674 | audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid, |
675 | uid, loginuid, sid); | |
676 | ||
677 | audit_log_format(ab, " audit_enabled=%d res=0", | |
678 | audit_enabled); | |
679 | audit_log_end(ab); | |
6a01b07f SG |
680 | return -EPERM; |
681 | } | |
1da177e4 LT |
682 | /* fallthrough */ |
683 | case AUDIT_LIST: | |
1da177e4 | 684 | err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid, |
93315ed6 | 685 | uid, seq, data, nlmsg_len(nlh), |
ce29b682 | 686 | loginuid, sid); |
93315ed6 AG |
687 | break; |
688 | case AUDIT_ADD_RULE: | |
689 | case AUDIT_DEL_RULE: | |
690 | if (nlmsg_len(nlh) < sizeof(struct audit_rule_data)) | |
691 | return -EINVAL; | |
1a6b9f23 | 692 | if (audit_enabled == AUDIT_LOCKED) { |
50397bd1 EP |
693 | audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid, |
694 | uid, loginuid, sid); | |
695 | ||
696 | audit_log_format(ab, " audit_enabled=%d res=0", | |
697 | audit_enabled); | |
698 | audit_log_end(ab); | |
6a01b07f SG |
699 | return -EPERM; |
700 | } | |
93315ed6 AG |
701 | /* fallthrough */ |
702 | case AUDIT_LIST_RULES: | |
703 | err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid, | |
704 | uid, seq, data, nlmsg_len(nlh), | |
ce29b682 | 705 | loginuid, sid); |
1da177e4 | 706 | break; |
74c3cbe3 AV |
707 | case AUDIT_TRIM: |
708 | audit_trim_trees(); | |
50397bd1 EP |
709 | |
710 | audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid, | |
711 | uid, loginuid, sid); | |
712 | ||
74c3cbe3 AV |
713 | audit_log_format(ab, " op=trim res=1"); |
714 | audit_log_end(ab); | |
715 | break; | |
716 | case AUDIT_MAKE_EQUIV: { | |
717 | void *bufp = data; | |
718 | u32 sizes[2]; | |
719 | size_t len = nlmsg_len(nlh); | |
720 | char *old, *new; | |
721 | ||
722 | err = -EINVAL; | |
723 | if (len < 2 * sizeof(u32)) | |
724 | break; | |
725 | memcpy(sizes, bufp, 2 * sizeof(u32)); | |
726 | bufp += 2 * sizeof(u32); | |
727 | len -= 2 * sizeof(u32); | |
728 | old = audit_unpack_string(&bufp, &len, sizes[0]); | |
729 | if (IS_ERR(old)) { | |
730 | err = PTR_ERR(old); | |
731 | break; | |
732 | } | |
733 | new = audit_unpack_string(&bufp, &len, sizes[1]); | |
734 | if (IS_ERR(new)) { | |
735 | err = PTR_ERR(new); | |
736 | kfree(old); | |
737 | break; | |
738 | } | |
739 | /* OK, here comes... */ | |
740 | err = audit_tag_tree(old, new); | |
741 | ||
50397bd1 EP |
742 | audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid, |
743 | uid, loginuid, sid); | |
744 | ||
74c3cbe3 AV |
745 | audit_log_format(ab, " op=make_equiv old="); |
746 | audit_log_untrustedstring(ab, old); | |
747 | audit_log_format(ab, " new="); | |
748 | audit_log_untrustedstring(ab, new); | |
749 | audit_log_format(ab, " res=%d", !err); | |
750 | audit_log_end(ab); | |
751 | kfree(old); | |
752 | kfree(new); | |
753 | break; | |
754 | } | |
c2f0c7c3 | 755 | case AUDIT_SIGNAL_INFO: |
1a70cd40 | 756 | err = selinux_sid_to_string(audit_sig_sid, &ctx, &len); |
e1396065 AV |
757 | if (err) |
758 | return err; | |
759 | sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL); | |
760 | if (!sig_data) { | |
761 | kfree(ctx); | |
762 | return -ENOMEM; | |
763 | } | |
764 | sig_data->uid = audit_sig_uid; | |
765 | sig_data->pid = audit_sig_pid; | |
766 | memcpy(sig_data->ctx, ctx, len); | |
767 | kfree(ctx); | |
5600b892 | 768 | audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_SIGNAL_INFO, |
e1396065 AV |
769 | 0, 0, sig_data, sizeof(*sig_data) + len); |
770 | kfree(sig_data); | |
c2f0c7c3 | 771 | break; |
522ed776 MT |
772 | case AUDIT_TTY_GET: { |
773 | struct audit_tty_status s; | |
774 | struct task_struct *tsk; | |
775 | ||
776 | read_lock(&tasklist_lock); | |
777 | tsk = find_task_by_pid(pid); | |
778 | if (!tsk) | |
779 | err = -ESRCH; | |
780 | else { | |
781 | spin_lock_irq(&tsk->sighand->siglock); | |
782 | s.enabled = tsk->signal->audit_tty != 0; | |
783 | spin_unlock_irq(&tsk->sighand->siglock); | |
784 | } | |
785 | read_unlock(&tasklist_lock); | |
786 | audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_TTY_GET, 0, 0, | |
787 | &s, sizeof(s)); | |
788 | break; | |
789 | } | |
790 | case AUDIT_TTY_SET: { | |
791 | struct audit_tty_status *s; | |
792 | struct task_struct *tsk; | |
793 | ||
794 | if (nlh->nlmsg_len < sizeof(struct audit_tty_status)) | |
795 | return -EINVAL; | |
796 | s = data; | |
797 | if (s->enabled != 0 && s->enabled != 1) | |
798 | return -EINVAL; | |
799 | read_lock(&tasklist_lock); | |
800 | tsk = find_task_by_pid(pid); | |
801 | if (!tsk) | |
802 | err = -ESRCH; | |
803 | else { | |
804 | spin_lock_irq(&tsk->sighand->siglock); | |
805 | tsk->signal->audit_tty = s->enabled != 0; | |
806 | spin_unlock_irq(&tsk->sighand->siglock); | |
807 | } | |
808 | read_unlock(&tasklist_lock); | |
809 | break; | |
810 | } | |
1da177e4 LT |
811 | default: |
812 | err = -EINVAL; | |
813 | break; | |
814 | } | |
815 | ||
816 | return err < 0 ? err : 0; | |
817 | } | |
818 | ||
b0dd25a8 RD |
819 | /* |
820 | * Get message from skb (based on rtnetlink_rcv_skb). Each message is | |
1da177e4 | 821 | * processed by audit_receive_msg. Malformed skbs with wrong length are |
b0dd25a8 RD |
822 | * discarded silently. |
823 | */ | |
2a0a6ebe | 824 | static void audit_receive_skb(struct sk_buff *skb) |
1da177e4 LT |
825 | { |
826 | int err; | |
827 | struct nlmsghdr *nlh; | |
828 | u32 rlen; | |
829 | ||
830 | while (skb->len >= NLMSG_SPACE(0)) { | |
b529ccf2 | 831 | nlh = nlmsg_hdr(skb); |
1da177e4 | 832 | if (nlh->nlmsg_len < sizeof(*nlh) || skb->len < nlh->nlmsg_len) |
2a0a6ebe | 833 | return; |
1da177e4 LT |
834 | rlen = NLMSG_ALIGN(nlh->nlmsg_len); |
835 | if (rlen > skb->len) | |
836 | rlen = skb->len; | |
837 | if ((err = audit_receive_msg(skb, nlh))) { | |
838 | netlink_ack(skb, nlh, err); | |
839 | } else if (nlh->nlmsg_flags & NLM_F_ACK) | |
840 | netlink_ack(skb, nlh, 0); | |
841 | skb_pull(skb, rlen); | |
842 | } | |
1da177e4 LT |
843 | } |
844 | ||
845 | /* Receive messages from netlink socket. */ | |
cd40b7d3 | 846 | static void audit_receive(struct sk_buff *skb) |
1da177e4 | 847 | { |
f368c07d | 848 | mutex_lock(&audit_cmd_mutex); |
cd40b7d3 | 849 | audit_receive_skb(skb); |
f368c07d | 850 | mutex_unlock(&audit_cmd_mutex); |
1da177e4 LT |
851 | } |
852 | ||
f368c07d AG |
853 | #ifdef CONFIG_AUDITSYSCALL |
854 | static const struct inotify_operations audit_inotify_ops = { | |
855 | .handle_event = audit_handle_ievent, | |
856 | .destroy_watch = audit_free_parent, | |
857 | }; | |
858 | #endif | |
1da177e4 LT |
859 | |
860 | /* Initialize audit support at boot time. */ | |
861 | static int __init audit_init(void) | |
862 | { | |
f368c07d | 863 | int i; |
f368c07d | 864 | |
1da177e4 LT |
865 | printk(KERN_INFO "audit: initializing netlink socket (%s)\n", |
866 | audit_default ? "enabled" : "disabled"); | |
b4b51029 EB |
867 | audit_sock = netlink_kernel_create(&init_net, NETLINK_AUDIT, 0, |
868 | audit_receive, NULL, THIS_MODULE); | |
1da177e4 LT |
869 | if (!audit_sock) |
870 | audit_panic("cannot initialize netlink socket"); | |
71e1c784 AG |
871 | else |
872 | audit_sock->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT; | |
1da177e4 | 873 | |
b7d11258 | 874 | skb_queue_head_init(&audit_skb_queue); |
1da177e4 LT |
875 | audit_initialized = 1; |
876 | audit_enabled = audit_default; | |
b593d384 | 877 | audit_ever_enabled |= !!audit_default; |
3dc7e315 DG |
878 | |
879 | /* Register the callback with selinux. This callback will be invoked | |
880 | * when a new policy is loaded. */ | |
881 | selinux_audit_set_callback(&selinux_audit_rule_update); | |
882 | ||
9ad9ad38 | 883 | audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized"); |
f368c07d AG |
884 | |
885 | #ifdef CONFIG_AUDITSYSCALL | |
886 | audit_ih = inotify_init(&audit_inotify_ops); | |
887 | if (IS_ERR(audit_ih)) | |
888 | audit_panic("cannot initialize inotify handle"); | |
6988434e | 889 | #endif |
f368c07d AG |
890 | |
891 | for (i = 0; i < AUDIT_INODE_BUCKETS; i++) | |
892 | INIT_LIST_HEAD(&audit_inode_hash[i]); | |
f368c07d | 893 | |
1da177e4 LT |
894 | return 0; |
895 | } | |
1da177e4 LT |
896 | __initcall(audit_init); |
897 | ||
898 | /* Process kernel command-line parameter at boot time. audit=0 or audit=1. */ | |
899 | static int __init audit_enable(char *str) | |
900 | { | |
901 | audit_default = !!simple_strtol(str, NULL, 0); | |
902 | printk(KERN_INFO "audit: %s%s\n", | |
903 | audit_default ? "enabled" : "disabled", | |
904 | audit_initialized ? "" : " (after initialization)"); | |
b593d384 | 905 | if (audit_initialized) { |
1da177e4 | 906 | audit_enabled = audit_default; |
b593d384 EP |
907 | audit_ever_enabled |= !!audit_default; |
908 | } | |
9b41046c | 909 | return 1; |
1da177e4 LT |
910 | } |
911 | ||
912 | __setup("audit=", audit_enable); | |
913 | ||
16e1904e CW |
914 | static void audit_buffer_free(struct audit_buffer *ab) |
915 | { | |
916 | unsigned long flags; | |
917 | ||
8fc6115c CW |
918 | if (!ab) |
919 | return; | |
920 | ||
5ac52f33 CW |
921 | if (ab->skb) |
922 | kfree_skb(ab->skb); | |
b7d11258 | 923 | |
16e1904e | 924 | spin_lock_irqsave(&audit_freelist_lock, flags); |
5d136a01 | 925 | if (audit_freelist_count > AUDIT_MAXFREE) |
16e1904e | 926 | kfree(ab); |
5d136a01 SH |
927 | else { |
928 | audit_freelist_count++; | |
16e1904e | 929 | list_add(&ab->list, &audit_freelist); |
5d136a01 | 930 | } |
16e1904e CW |
931 | spin_unlock_irqrestore(&audit_freelist_lock, flags); |
932 | } | |
933 | ||
c0404993 | 934 | static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx, |
dd0fc66f | 935 | gfp_t gfp_mask, int type) |
16e1904e CW |
936 | { |
937 | unsigned long flags; | |
938 | struct audit_buffer *ab = NULL; | |
c0404993 | 939 | struct nlmsghdr *nlh; |
16e1904e CW |
940 | |
941 | spin_lock_irqsave(&audit_freelist_lock, flags); | |
942 | if (!list_empty(&audit_freelist)) { | |
943 | ab = list_entry(audit_freelist.next, | |
944 | struct audit_buffer, list); | |
945 | list_del(&ab->list); | |
946 | --audit_freelist_count; | |
947 | } | |
948 | spin_unlock_irqrestore(&audit_freelist_lock, flags); | |
949 | ||
950 | if (!ab) { | |
4332bdd3 | 951 | ab = kmalloc(sizeof(*ab), gfp_mask); |
16e1904e | 952 | if (!ab) |
8fc6115c | 953 | goto err; |
16e1904e | 954 | } |
8fc6115c | 955 | |
4332bdd3 | 956 | ab->skb = alloc_skb(AUDIT_BUFSIZ, gfp_mask); |
5ac52f33 | 957 | if (!ab->skb) |
8fc6115c CW |
958 | goto err; |
959 | ||
b7d11258 | 960 | ab->ctx = ctx; |
9ad9ad38 | 961 | ab->gfp_mask = gfp_mask; |
c0404993 SG |
962 | nlh = (struct nlmsghdr *)skb_put(ab->skb, NLMSG_SPACE(0)); |
963 | nlh->nlmsg_type = type; | |
964 | nlh->nlmsg_flags = 0; | |
965 | nlh->nlmsg_pid = 0; | |
966 | nlh->nlmsg_seq = 0; | |
16e1904e | 967 | return ab; |
8fc6115c CW |
968 | err: |
969 | audit_buffer_free(ab); | |
970 | return NULL; | |
16e1904e | 971 | } |
1da177e4 | 972 | |
b0dd25a8 RD |
973 | /** |
974 | * audit_serial - compute a serial number for the audit record | |
975 | * | |
976 | * Compute a serial number for the audit record. Audit records are | |
bfb4496e DW |
977 | * written to user-space as soon as they are generated, so a complete |
978 | * audit record may be written in several pieces. The timestamp of the | |
979 | * record and this serial number are used by the user-space tools to | |
980 | * determine which pieces belong to the same audit record. The | |
981 | * (timestamp,serial) tuple is unique for each syscall and is live from | |
982 | * syscall entry to syscall exit. | |
983 | * | |
bfb4496e DW |
984 | * NOTE: Another possibility is to store the formatted records off the |
985 | * audit context (for those records that have a context), and emit them | |
986 | * all at syscall exit. However, this could delay the reporting of | |
987 | * significant errors until syscall exit (or never, if the system | |
b0dd25a8 RD |
988 | * halts). |
989 | */ | |
bfb4496e DW |
990 | unsigned int audit_serial(void) |
991 | { | |
34af946a | 992 | static DEFINE_SPINLOCK(serial_lock); |
d5b454f2 DW |
993 | static unsigned int serial = 0; |
994 | ||
995 | unsigned long flags; | |
996 | unsigned int ret; | |
bfb4496e | 997 | |
d5b454f2 | 998 | spin_lock_irqsave(&serial_lock, flags); |
bfb4496e | 999 | do { |
ce625a80 DW |
1000 | ret = ++serial; |
1001 | } while (unlikely(!ret)); | |
d5b454f2 | 1002 | spin_unlock_irqrestore(&serial_lock, flags); |
bfb4496e | 1003 | |
d5b454f2 | 1004 | return ret; |
bfb4496e DW |
1005 | } |
1006 | ||
5600b892 | 1007 | static inline void audit_get_stamp(struct audit_context *ctx, |
bfb4496e DW |
1008 | struct timespec *t, unsigned int *serial) |
1009 | { | |
1010 | if (ctx) | |
1011 | auditsc_get_stamp(ctx, t, serial); | |
1012 | else { | |
1013 | *t = CURRENT_TIME; | |
1014 | *serial = audit_serial(); | |
1015 | } | |
1016 | } | |
1017 | ||
1da177e4 LT |
1018 | /* Obtain an audit buffer. This routine does locking to obtain the |
1019 | * audit buffer, but then no locking is required for calls to | |
1020 | * audit_log_*format. If the tsk is a task that is currently in a | |
1021 | * syscall, then the syscall is marked as auditable and an audit record | |
1022 | * will be written at syscall exit. If there is no associated task, tsk | |
1023 | * should be NULL. */ | |
9ad9ad38 | 1024 | |
b0dd25a8 RD |
1025 | /** |
1026 | * audit_log_start - obtain an audit buffer | |
1027 | * @ctx: audit_context (may be NULL) | |
1028 | * @gfp_mask: type of allocation | |
1029 | * @type: audit message type | |
1030 | * | |
1031 | * Returns audit_buffer pointer on success or NULL on error. | |
1032 | * | |
1033 | * Obtain an audit buffer. This routine does locking to obtain the | |
1034 | * audit buffer, but then no locking is required for calls to | |
1035 | * audit_log_*format. If the task (ctx) is a task that is currently in a | |
1036 | * syscall, then the syscall is marked as auditable and an audit record | |
1037 | * will be written at syscall exit. If there is no associated task, then | |
1038 | * task context (ctx) should be NULL. | |
1039 | */ | |
9796fdd8 | 1040 | struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, |
9ad9ad38 | 1041 | int type) |
1da177e4 LT |
1042 | { |
1043 | struct audit_buffer *ab = NULL; | |
1da177e4 | 1044 | struct timespec t; |
ef00be05 | 1045 | unsigned int uninitialized_var(serial); |
9ad9ad38 | 1046 | int reserve; |
ac4cec44 | 1047 | unsigned long timeout_start = jiffies; |
1da177e4 LT |
1048 | |
1049 | if (!audit_initialized) | |
1050 | return NULL; | |
1051 | ||
c8edc80c DK |
1052 | if (unlikely(audit_filter_type(type))) |
1053 | return NULL; | |
1054 | ||
9ad9ad38 DW |
1055 | if (gfp_mask & __GFP_WAIT) |
1056 | reserve = 0; | |
1057 | else | |
5600b892 | 1058 | reserve = 5; /* Allow atomic callers to go up to five |
9ad9ad38 DW |
1059 | entries over the normal backlog limit */ |
1060 | ||
1061 | while (audit_backlog_limit | |
1062 | && skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) { | |
ac4cec44 DW |
1063 | if (gfp_mask & __GFP_WAIT && audit_backlog_wait_time |
1064 | && time_before(jiffies, timeout_start + audit_backlog_wait_time)) { | |
1065 | ||
9ad9ad38 DW |
1066 | /* Wait for auditd to drain the queue a little */ |
1067 | DECLARE_WAITQUEUE(wait, current); | |
1068 | set_current_state(TASK_INTERRUPTIBLE); | |
1069 | add_wait_queue(&audit_backlog_wait, &wait); | |
1070 | ||
1071 | if (audit_backlog_limit && | |
1072 | skb_queue_len(&audit_skb_queue) > audit_backlog_limit) | |
ac4cec44 | 1073 | schedule_timeout(timeout_start + audit_backlog_wait_time - jiffies); |
9ad9ad38 DW |
1074 | |
1075 | __set_current_state(TASK_RUNNING); | |
1076 | remove_wait_queue(&audit_backlog_wait, &wait); | |
ac4cec44 | 1077 | continue; |
9ad9ad38 | 1078 | } |
320f1b1e | 1079 | if (audit_rate_check() && printk_ratelimit()) |
fb19b4c6 DW |
1080 | printk(KERN_WARNING |
1081 | "audit: audit_backlog=%d > " | |
1082 | "audit_backlog_limit=%d\n", | |
1083 | skb_queue_len(&audit_skb_queue), | |
1084 | audit_backlog_limit); | |
1085 | audit_log_lost("backlog limit exceeded"); | |
ac4cec44 DW |
1086 | audit_backlog_wait_time = audit_backlog_wait_overflow; |
1087 | wake_up(&audit_backlog_wait); | |
fb19b4c6 DW |
1088 | return NULL; |
1089 | } | |
1090 | ||
9ad9ad38 | 1091 | ab = audit_buffer_alloc(ctx, gfp_mask, type); |
1da177e4 LT |
1092 | if (!ab) { |
1093 | audit_log_lost("out of memory in audit_log_start"); | |
1094 | return NULL; | |
1095 | } | |
1096 | ||
bfb4496e | 1097 | audit_get_stamp(ab->ctx, &t, &serial); |
197c69c6 | 1098 | |
1da177e4 LT |
1099 | audit_log_format(ab, "audit(%lu.%03lu:%u): ", |
1100 | t.tv_sec, t.tv_nsec/1000000, serial); | |
1101 | return ab; | |
1102 | } | |
1103 | ||
8fc6115c | 1104 | /** |
5ac52f33 | 1105 | * audit_expand - expand skb in the audit buffer |
8fc6115c | 1106 | * @ab: audit_buffer |
b0dd25a8 | 1107 | * @extra: space to add at tail of the skb |
8fc6115c CW |
1108 | * |
1109 | * Returns 0 (no space) on failed expansion, or available space if | |
1110 | * successful. | |
1111 | */ | |
e3b926b4 | 1112 | static inline int audit_expand(struct audit_buffer *ab, int extra) |
8fc6115c | 1113 | { |
5ac52f33 | 1114 | struct sk_buff *skb = ab->skb; |
406a1d86 HX |
1115 | int oldtail = skb_tailroom(skb); |
1116 | int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask); | |
1117 | int newtail = skb_tailroom(skb); | |
1118 | ||
5ac52f33 CW |
1119 | if (ret < 0) { |
1120 | audit_log_lost("out of memory in audit_expand"); | |
8fc6115c | 1121 | return 0; |
5ac52f33 | 1122 | } |
406a1d86 HX |
1123 | |
1124 | skb->truesize += newtail - oldtail; | |
1125 | return newtail; | |
8fc6115c | 1126 | } |
1da177e4 | 1127 | |
b0dd25a8 RD |
1128 | /* |
1129 | * Format an audit message into the audit buffer. If there isn't enough | |
1da177e4 LT |
1130 | * room in the audit buffer, more room will be allocated and vsnprint |
1131 | * will be called a second time. Currently, we assume that a printk | |
b0dd25a8 RD |
1132 | * can't format message larger than 1024 bytes, so we don't either. |
1133 | */ | |
1da177e4 LT |
1134 | static void audit_log_vformat(struct audit_buffer *ab, const char *fmt, |
1135 | va_list args) | |
1136 | { | |
1137 | int len, avail; | |
5ac52f33 | 1138 | struct sk_buff *skb; |
eecb0a73 | 1139 | va_list args2; |
1da177e4 LT |
1140 | |
1141 | if (!ab) | |
1142 | return; | |
1143 | ||
5ac52f33 CW |
1144 | BUG_ON(!ab->skb); |
1145 | skb = ab->skb; | |
1146 | avail = skb_tailroom(skb); | |
1147 | if (avail == 0) { | |
e3b926b4 | 1148 | avail = audit_expand(ab, AUDIT_BUFSIZ); |
8fc6115c CW |
1149 | if (!avail) |
1150 | goto out; | |
1da177e4 | 1151 | } |
eecb0a73 | 1152 | va_copy(args2, args); |
27a884dc | 1153 | len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args); |
1da177e4 LT |
1154 | if (len >= avail) { |
1155 | /* The printk buffer is 1024 bytes long, so if we get | |
1156 | * here and AUDIT_BUFSIZ is at least 1024, then we can | |
1157 | * log everything that printk could have logged. */ | |
b0dd25a8 RD |
1158 | avail = audit_expand(ab, |
1159 | max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail)); | |
8fc6115c CW |
1160 | if (!avail) |
1161 | goto out; | |
27a884dc | 1162 | len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2); |
1da177e4 | 1163 | } |
148b38dc | 1164 | va_end(args2); |
168b7173 SG |
1165 | if (len > 0) |
1166 | skb_put(skb, len); | |
8fc6115c CW |
1167 | out: |
1168 | return; | |
1da177e4 LT |
1169 | } |
1170 | ||
b0dd25a8 RD |
1171 | /** |
1172 | * audit_log_format - format a message into the audit buffer. | |
1173 | * @ab: audit_buffer | |
1174 | * @fmt: format string | |
1175 | * @...: optional parameters matching @fmt string | |
1176 | * | |
1177 | * All the work is done in audit_log_vformat. | |
1178 | */ | |
1da177e4 LT |
1179 | void audit_log_format(struct audit_buffer *ab, const char *fmt, ...) |
1180 | { | |
1181 | va_list args; | |
1182 | ||
1183 | if (!ab) | |
1184 | return; | |
1185 | va_start(args, fmt); | |
1186 | audit_log_vformat(ab, fmt, args); | |
1187 | va_end(args); | |
1188 | } | |
1189 | ||
b0dd25a8 RD |
1190 | /** |
1191 | * audit_log_hex - convert a buffer to hex and append it to the audit skb | |
1192 | * @ab: the audit_buffer | |
1193 | * @buf: buffer to convert to hex | |
1194 | * @len: length of @buf to be converted | |
1195 | * | |
1196 | * No return value; failure to expand is silently ignored. | |
1197 | * | |
1198 | * This function will take the passed buf and convert it into a string of | |
1199 | * ascii hex digits. The new string is placed onto the skb. | |
1200 | */ | |
1201 | void audit_log_hex(struct audit_buffer *ab, const unsigned char *buf, | |
168b7173 | 1202 | size_t len) |
83c7d091 | 1203 | { |
168b7173 SG |
1204 | int i, avail, new_len; |
1205 | unsigned char *ptr; | |
1206 | struct sk_buff *skb; | |
1207 | static const unsigned char *hex = "0123456789ABCDEF"; | |
1208 | ||
8ef2d304 AG |
1209 | if (!ab) |
1210 | return; | |
1211 | ||
168b7173 SG |
1212 | BUG_ON(!ab->skb); |
1213 | skb = ab->skb; | |
1214 | avail = skb_tailroom(skb); | |
1215 | new_len = len<<1; | |
1216 | if (new_len >= avail) { | |
1217 | /* Round the buffer request up to the next multiple */ | |
1218 | new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1); | |
1219 | avail = audit_expand(ab, new_len); | |
1220 | if (!avail) | |
1221 | return; | |
1222 | } | |
83c7d091 | 1223 | |
27a884dc | 1224 | ptr = skb_tail_pointer(skb); |
168b7173 SG |
1225 | for (i=0; i<len; i++) { |
1226 | *ptr++ = hex[(buf[i] & 0xF0)>>4]; /* Upper nibble */ | |
1227 | *ptr++ = hex[buf[i] & 0x0F]; /* Lower nibble */ | |
1228 | } | |
1229 | *ptr = 0; | |
1230 | skb_put(skb, len << 1); /* new string is twice the old string */ | |
83c7d091 DW |
1231 | } |
1232 | ||
9c937dcc AG |
1233 | /* |
1234 | * Format a string of no more than slen characters into the audit buffer, | |
1235 | * enclosed in quote marks. | |
1236 | */ | |
1237 | static void audit_log_n_string(struct audit_buffer *ab, size_t slen, | |
1238 | const char *string) | |
1239 | { | |
1240 | int avail, new_len; | |
1241 | unsigned char *ptr; | |
1242 | struct sk_buff *skb; | |
1243 | ||
8ef2d304 AG |
1244 | if (!ab) |
1245 | return; | |
1246 | ||
9c937dcc AG |
1247 | BUG_ON(!ab->skb); |
1248 | skb = ab->skb; | |
1249 | avail = skb_tailroom(skb); | |
1250 | new_len = slen + 3; /* enclosing quotes + null terminator */ | |
1251 | if (new_len > avail) { | |
1252 | avail = audit_expand(ab, new_len); | |
1253 | if (!avail) | |
1254 | return; | |
1255 | } | |
27a884dc | 1256 | ptr = skb_tail_pointer(skb); |
9c937dcc AG |
1257 | *ptr++ = '"'; |
1258 | memcpy(ptr, string, slen); | |
1259 | ptr += slen; | |
1260 | *ptr++ = '"'; | |
1261 | *ptr = 0; | |
1262 | skb_put(skb, slen + 2); /* don't include null terminator */ | |
1263 | } | |
1264 | ||
de6bbd1d EP |
1265 | /** |
1266 | * audit_string_contains_control - does a string need to be logged in hex | |
1267 | * @string - string to be checked | |
1268 | * @len - max length of the string to check | |
1269 | */ | |
1270 | int audit_string_contains_control(const char *string, size_t len) | |
1271 | { | |
1272 | const unsigned char *p; | |
1273 | for (p = string; p < (const unsigned char *)string + len && *p; p++) { | |
1274 | if (*p == '"' || *p < 0x21 || *p > 0x7f) | |
1275 | return 1; | |
1276 | } | |
1277 | return 0; | |
1278 | } | |
1279 | ||
b0dd25a8 | 1280 | /** |
522ed776 | 1281 | * audit_log_n_untrustedstring - log a string that may contain random characters |
b0dd25a8 | 1282 | * @ab: audit_buffer |
9c937dcc | 1283 | * @len: lenth of string (not including trailing null) |
b0dd25a8 RD |
1284 | * @string: string to be logged |
1285 | * | |
1286 | * This code will escape a string that is passed to it if the string | |
1287 | * contains a control character, unprintable character, double quote mark, | |
168b7173 | 1288 | * or a space. Unescaped strings will start and end with a double quote mark. |
b0dd25a8 | 1289 | * Strings that are escaped are printed in hex (2 digits per char). |
9c937dcc AG |
1290 | * |
1291 | * The caller specifies the number of characters in the string to log, which may | |
1292 | * or may not be the entire string. | |
b0dd25a8 | 1293 | */ |
de6bbd1d EP |
1294 | void audit_log_n_untrustedstring(struct audit_buffer *ab, size_t len, |
1295 | const char *string) | |
83c7d091 | 1296 | { |
de6bbd1d EP |
1297 | if (audit_string_contains_control(string, len)) |
1298 | audit_log_hex(ab, string, len); | |
1299 | else | |
1300 | audit_log_n_string(ab, len, string); | |
83c7d091 DW |
1301 | } |
1302 | ||
9c937dcc | 1303 | /** |
522ed776 | 1304 | * audit_log_untrustedstring - log a string that may contain random characters |
9c937dcc AG |
1305 | * @ab: audit_buffer |
1306 | * @string: string to be logged | |
1307 | * | |
522ed776 | 1308 | * Same as audit_log_n_untrustedstring(), except that strlen is used to |
9c937dcc AG |
1309 | * determine string length. |
1310 | */ | |
de6bbd1d | 1311 | void audit_log_untrustedstring(struct audit_buffer *ab, const char *string) |
9c937dcc | 1312 | { |
de6bbd1d | 1313 | audit_log_n_untrustedstring(ab, strlen(string), string); |
9c937dcc AG |
1314 | } |
1315 | ||
168b7173 | 1316 | /* This is a helper-function to print the escaped d_path */ |
1da177e4 | 1317 | void audit_log_d_path(struct audit_buffer *ab, const char *prefix, |
44707fdf | 1318 | struct path *path) |
1da177e4 | 1319 | { |
44707fdf | 1320 | char *p, *pathname; |
1da177e4 | 1321 | |
8fc6115c CW |
1322 | if (prefix) |
1323 | audit_log_format(ab, " %s", prefix); | |
1da177e4 | 1324 | |
168b7173 | 1325 | /* We will allow 11 spaces for ' (deleted)' to be appended */ |
44707fdf JB |
1326 | pathname = kmalloc(PATH_MAX+11, ab->gfp_mask); |
1327 | if (!pathname) { | |
168b7173 SG |
1328 | audit_log_format(ab, "<no memory>"); |
1329 | return; | |
1da177e4 | 1330 | } |
cf28b486 | 1331 | p = d_path(path, pathname, PATH_MAX+11); |
168b7173 SG |
1332 | if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */ |
1333 | /* FIXME: can we save some information here? */ | |
1334 | audit_log_format(ab, "<too long>"); | |
5600b892 | 1335 | } else |
168b7173 | 1336 | audit_log_untrustedstring(ab, p); |
44707fdf | 1337 | kfree(pathname); |
1da177e4 LT |
1338 | } |
1339 | ||
b0dd25a8 RD |
1340 | /** |
1341 | * audit_log_end - end one audit record | |
1342 | * @ab: the audit_buffer | |
1343 | * | |
1344 | * The netlink_* functions cannot be called inside an irq context, so | |
1345 | * the audit buffer is placed on a queue and a tasklet is scheduled to | |
1da177e4 | 1346 | * remove them from the queue outside the irq context. May be called in |
b0dd25a8 RD |
1347 | * any context. |
1348 | */ | |
b7d11258 | 1349 | void audit_log_end(struct audit_buffer *ab) |
1da177e4 | 1350 | { |
1da177e4 LT |
1351 | if (!ab) |
1352 | return; | |
1353 | if (!audit_rate_check()) { | |
1354 | audit_log_lost("rate limit exceeded"); | |
1355 | } else { | |
8d07a67c | 1356 | struct nlmsghdr *nlh = nlmsg_hdr(ab->skb); |
b7d11258 | 1357 | if (audit_pid) { |
b7d11258 DW |
1358 | nlh->nlmsg_len = ab->skb->len - NLMSG_SPACE(0); |
1359 | skb_queue_tail(&audit_skb_queue, ab->skb); | |
1360 | ab->skb = NULL; | |
1361 | wake_up_interruptible(&kauditd_wait); | |
8d07a67c SG |
1362 | } else if (nlh->nlmsg_type != AUDIT_EOE) { |
1363 | if (printk_ratelimit()) { | |
1364 | printk(KERN_NOTICE "type=%d %s\n", | |
1365 | nlh->nlmsg_type, | |
1366 | ab->skb->data + NLMSG_SPACE(0)); | |
1367 | } else | |
1368 | audit_log_lost("printk limit exceeded\n"); | |
b7d11258 | 1369 | } |
1da177e4 | 1370 | } |
16e1904e | 1371 | audit_buffer_free(ab); |
1da177e4 LT |
1372 | } |
1373 | ||
b0dd25a8 RD |
1374 | /** |
1375 | * audit_log - Log an audit record | |
1376 | * @ctx: audit context | |
1377 | * @gfp_mask: type of allocation | |
1378 | * @type: audit message type | |
1379 | * @fmt: format string to use | |
1380 | * @...: variable parameters matching the format string | |
1381 | * | |
1382 | * This is a convenience function that calls audit_log_start, | |
1383 | * audit_log_vformat, and audit_log_end. It may be called | |
1384 | * in any context. | |
1385 | */ | |
5600b892 | 1386 | void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type, |
9ad9ad38 | 1387 | const char *fmt, ...) |
1da177e4 LT |
1388 | { |
1389 | struct audit_buffer *ab; | |
1390 | va_list args; | |
1391 | ||
9ad9ad38 | 1392 | ab = audit_log_start(ctx, gfp_mask, type); |
1da177e4 LT |
1393 | if (ab) { |
1394 | va_start(args, fmt); | |
1395 | audit_log_vformat(ab, fmt, args); | |
1396 | va_end(args); | |
1397 | audit_log_end(ab); | |
1398 | } | |
1399 | } | |
bf45da97 | 1400 | |
1401 | EXPORT_SYMBOL(audit_log_start); | |
1402 | EXPORT_SYMBOL(audit_log_end); | |
1403 | EXPORT_SYMBOL(audit_log_format); | |
1404 | EXPORT_SYMBOL(audit_log); |