xref: /openbmc/linux/kernel/auditfilter.c (revision e8f6f3b4)
1 /* auditfilter.c -- filtering of audit events
2  *
3  * Copyright 2003-2004 Red Hat, Inc.
4  * Copyright 2005 Hewlett-Packard Development Company, L.P.
5  * Copyright 2005 IBM Corporation
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
20  */
21 
22 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23 
24 #include <linux/kernel.h>
25 #include <linux/audit.h>
26 #include <linux/kthread.h>
27 #include <linux/mutex.h>
28 #include <linux/fs.h>
29 #include <linux/namei.h>
30 #include <linux/netlink.h>
31 #include <linux/sched.h>
32 #include <linux/slab.h>
33 #include <linux/security.h>
34 #include <net/net_namespace.h>
35 #include <net/sock.h>
36 #include "audit.h"
37 
38 /*
39  * Locking model:
40  *
41  * audit_filter_mutex:
42  * 		Synchronizes writes and blocking reads of audit's filterlist
43  * 		data.  Rcu is used to traverse the filterlist and access
44  * 		contents of structs audit_entry, audit_watch and opaque
45  * 		LSM rules during filtering.  If modified, these structures
46  * 		must be copied and replace their counterparts in the filterlist.
47  * 		An audit_parent struct is not accessed during filtering, so may
48  * 		be written directly provided audit_filter_mutex is held.
49  */
50 
51 /* Audit filter lists, defined in <linux/audit.h> */
52 struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
53 	LIST_HEAD_INIT(audit_filter_list[0]),
54 	LIST_HEAD_INIT(audit_filter_list[1]),
55 	LIST_HEAD_INIT(audit_filter_list[2]),
56 	LIST_HEAD_INIT(audit_filter_list[3]),
57 	LIST_HEAD_INIT(audit_filter_list[4]),
58 	LIST_HEAD_INIT(audit_filter_list[5]),
59 #if AUDIT_NR_FILTERS != 6
60 #error Fix audit_filter_list initialiser
61 #endif
62 };
63 static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
64 	LIST_HEAD_INIT(audit_rules_list[0]),
65 	LIST_HEAD_INIT(audit_rules_list[1]),
66 	LIST_HEAD_INIT(audit_rules_list[2]),
67 	LIST_HEAD_INIT(audit_rules_list[3]),
68 	LIST_HEAD_INIT(audit_rules_list[4]),
69 	LIST_HEAD_INIT(audit_rules_list[5]),
70 };
71 
72 DEFINE_MUTEX(audit_filter_mutex);
73 
74 static void audit_free_lsm_field(struct audit_field *f)
75 {
76 	switch (f->type) {
77 	case AUDIT_SUBJ_USER:
78 	case AUDIT_SUBJ_ROLE:
79 	case AUDIT_SUBJ_TYPE:
80 	case AUDIT_SUBJ_SEN:
81 	case AUDIT_SUBJ_CLR:
82 	case AUDIT_OBJ_USER:
83 	case AUDIT_OBJ_ROLE:
84 	case AUDIT_OBJ_TYPE:
85 	case AUDIT_OBJ_LEV_LOW:
86 	case AUDIT_OBJ_LEV_HIGH:
87 		kfree(f->lsm_str);
88 		security_audit_rule_free(f->lsm_rule);
89 	}
90 }
91 
92 static inline void audit_free_rule(struct audit_entry *e)
93 {
94 	int i;
95 	struct audit_krule *erule = &e->rule;
96 
97 	/* some rules don't have associated watches */
98 	if (erule->watch)
99 		audit_put_watch(erule->watch);
100 	if (erule->fields)
101 		for (i = 0; i < erule->field_count; i++)
102 			audit_free_lsm_field(&erule->fields[i]);
103 	kfree(erule->fields);
104 	kfree(erule->filterkey);
105 	kfree(e);
106 }
107 
108 void audit_free_rule_rcu(struct rcu_head *head)
109 {
110 	struct audit_entry *e = container_of(head, struct audit_entry, rcu);
111 	audit_free_rule(e);
112 }
113 
114 /* Initialize an audit filterlist entry. */
115 static inline struct audit_entry *audit_init_entry(u32 field_count)
116 {
117 	struct audit_entry *entry;
118 	struct audit_field *fields;
119 
120 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
121 	if (unlikely(!entry))
122 		return NULL;
123 
124 	fields = kcalloc(field_count, sizeof(*fields), GFP_KERNEL);
125 	if (unlikely(!fields)) {
126 		kfree(entry);
127 		return NULL;
128 	}
129 	entry->rule.fields = fields;
130 
131 	return entry;
132 }
133 
134 /* Unpack a filter field's string representation from user-space
135  * buffer. */
136 char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
137 {
138 	char *str;
139 
140 	if (!*bufp || (len == 0) || (len > *remain))
141 		return ERR_PTR(-EINVAL);
142 
143 	/* Of the currently implemented string fields, PATH_MAX
144 	 * defines the longest valid length.
145 	 */
146 	if (len > PATH_MAX)
147 		return ERR_PTR(-ENAMETOOLONG);
148 
149 	str = kmalloc(len + 1, GFP_KERNEL);
150 	if (unlikely(!str))
151 		return ERR_PTR(-ENOMEM);
152 
153 	memcpy(str, *bufp, len);
154 	str[len] = 0;
155 	*bufp += len;
156 	*remain -= len;
157 
158 	return str;
159 }
160 
161 /* Translate an inode field to kernel respresentation. */
162 static inline int audit_to_inode(struct audit_krule *krule,
163 				 struct audit_field *f)
164 {
165 	if (krule->listnr != AUDIT_FILTER_EXIT ||
166 	    krule->inode_f || krule->watch || krule->tree ||
167 	    (f->op != Audit_equal && f->op != Audit_not_equal))
168 		return -EINVAL;
169 
170 	krule->inode_f = f;
171 	return 0;
172 }
173 
174 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
175 
176 int __init audit_register_class(int class, unsigned *list)
177 {
178 	__u32 *p = kcalloc(AUDIT_BITMASK_SIZE, sizeof(__u32), GFP_KERNEL);
179 	if (!p)
180 		return -ENOMEM;
181 	while (*list != ~0U) {
182 		unsigned n = *list++;
183 		if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
184 			kfree(p);
185 			return -EINVAL;
186 		}
187 		p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
188 	}
189 	if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
190 		kfree(p);
191 		return -EINVAL;
192 	}
193 	classes[class] = p;
194 	return 0;
195 }
196 
197 int audit_match_class(int class, unsigned syscall)
198 {
199 	if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
200 		return 0;
201 	if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
202 		return 0;
203 	return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
204 }
205 
206 #ifdef CONFIG_AUDITSYSCALL
207 static inline int audit_match_class_bits(int class, u32 *mask)
208 {
209 	int i;
210 
211 	if (classes[class]) {
212 		for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
213 			if (mask[i] & classes[class][i])
214 				return 0;
215 	}
216 	return 1;
217 }
218 
219 static int audit_match_signal(struct audit_entry *entry)
220 {
221 	struct audit_field *arch = entry->rule.arch_f;
222 
223 	if (!arch) {
224 		/* When arch is unspecified, we must check both masks on biarch
225 		 * as syscall number alone is ambiguous. */
226 		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
227 					       entry->rule.mask) &&
228 			audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
229 					       entry->rule.mask));
230 	}
231 
232 	switch(audit_classify_arch(arch->val)) {
233 	case 0: /* native */
234 		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
235 					       entry->rule.mask));
236 	case 1: /* 32bit on biarch */
237 		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
238 					       entry->rule.mask));
239 	default:
240 		return 1;
241 	}
242 }
243 #endif
244 
245 /* Common user-space to kernel rule translation. */
246 static inline struct audit_entry *audit_to_entry_common(struct audit_rule_data *rule)
247 {
248 	unsigned listnr;
249 	struct audit_entry *entry;
250 	int i, err;
251 
252 	err = -EINVAL;
253 	listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
254 	switch(listnr) {
255 	default:
256 		goto exit_err;
257 #ifdef CONFIG_AUDITSYSCALL
258 	case AUDIT_FILTER_ENTRY:
259 		if (rule->action == AUDIT_ALWAYS)
260 			goto exit_err;
261 	case AUDIT_FILTER_EXIT:
262 	case AUDIT_FILTER_TASK:
263 #endif
264 	case AUDIT_FILTER_USER:
265 	case AUDIT_FILTER_TYPE:
266 		;
267 	}
268 	if (unlikely(rule->action == AUDIT_POSSIBLE)) {
269 		pr_err("AUDIT_POSSIBLE is deprecated\n");
270 		goto exit_err;
271 	}
272 	if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
273 		goto exit_err;
274 	if (rule->field_count > AUDIT_MAX_FIELDS)
275 		goto exit_err;
276 
277 	err = -ENOMEM;
278 	entry = audit_init_entry(rule->field_count);
279 	if (!entry)
280 		goto exit_err;
281 
282 	entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
283 	entry->rule.listnr = listnr;
284 	entry->rule.action = rule->action;
285 	entry->rule.field_count = rule->field_count;
286 
287 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
288 		entry->rule.mask[i] = rule->mask[i];
289 
290 	for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
291 		int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
292 		__u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
293 		__u32 *class;
294 
295 		if (!(*p & AUDIT_BIT(bit)))
296 			continue;
297 		*p &= ~AUDIT_BIT(bit);
298 		class = classes[i];
299 		if (class) {
300 			int j;
301 			for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
302 				entry->rule.mask[j] |= class[j];
303 		}
304 	}
305 
306 	return entry;
307 
308 exit_err:
309 	return ERR_PTR(err);
310 }
311 
312 static u32 audit_ops[] =
313 {
314 	[Audit_equal] = AUDIT_EQUAL,
315 	[Audit_not_equal] = AUDIT_NOT_EQUAL,
316 	[Audit_bitmask] = AUDIT_BIT_MASK,
317 	[Audit_bittest] = AUDIT_BIT_TEST,
318 	[Audit_lt] = AUDIT_LESS_THAN,
319 	[Audit_gt] = AUDIT_GREATER_THAN,
320 	[Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
321 	[Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
322 };
323 
324 static u32 audit_to_op(u32 op)
325 {
326 	u32 n;
327 	for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
328 		;
329 	return n;
330 }
331 
332 /* check if an audit field is valid */
333 static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
334 {
335 	switch(f->type) {
336 	case AUDIT_MSGTYPE:
337 		if (entry->rule.listnr != AUDIT_FILTER_TYPE &&
338 		    entry->rule.listnr != AUDIT_FILTER_USER)
339 			return -EINVAL;
340 		break;
341 	};
342 
343 	switch(f->type) {
344 	default:
345 		return -EINVAL;
346 	case AUDIT_UID:
347 	case AUDIT_EUID:
348 	case AUDIT_SUID:
349 	case AUDIT_FSUID:
350 	case AUDIT_LOGINUID:
351 	case AUDIT_OBJ_UID:
352 	case AUDIT_GID:
353 	case AUDIT_EGID:
354 	case AUDIT_SGID:
355 	case AUDIT_FSGID:
356 	case AUDIT_OBJ_GID:
357 	case AUDIT_PID:
358 	case AUDIT_PERS:
359 	case AUDIT_MSGTYPE:
360 	case AUDIT_PPID:
361 	case AUDIT_DEVMAJOR:
362 	case AUDIT_DEVMINOR:
363 	case AUDIT_EXIT:
364 	case AUDIT_SUCCESS:
365 	case AUDIT_INODE:
366 		/* bit ops are only useful on syscall args */
367 		if (f->op == Audit_bitmask || f->op == Audit_bittest)
368 			return -EINVAL;
369 		break;
370 	case AUDIT_ARG0:
371 	case AUDIT_ARG1:
372 	case AUDIT_ARG2:
373 	case AUDIT_ARG3:
374 	case AUDIT_SUBJ_USER:
375 	case AUDIT_SUBJ_ROLE:
376 	case AUDIT_SUBJ_TYPE:
377 	case AUDIT_SUBJ_SEN:
378 	case AUDIT_SUBJ_CLR:
379 	case AUDIT_OBJ_USER:
380 	case AUDIT_OBJ_ROLE:
381 	case AUDIT_OBJ_TYPE:
382 	case AUDIT_OBJ_LEV_LOW:
383 	case AUDIT_OBJ_LEV_HIGH:
384 	case AUDIT_WATCH:
385 	case AUDIT_DIR:
386 	case AUDIT_FILTERKEY:
387 		break;
388 	case AUDIT_LOGINUID_SET:
389 		if ((f->val != 0) && (f->val != 1))
390 			return -EINVAL;
391 	/* FALL THROUGH */
392 	case AUDIT_ARCH:
393 		if (f->op != Audit_not_equal && f->op != Audit_equal)
394 			return -EINVAL;
395 		break;
396 	case AUDIT_PERM:
397 		if (f->val & ~15)
398 			return -EINVAL;
399 		break;
400 	case AUDIT_FILETYPE:
401 		if (f->val & ~S_IFMT)
402 			return -EINVAL;
403 		break;
404 	case AUDIT_FIELD_COMPARE:
405 		if (f->val > AUDIT_MAX_FIELD_COMPARE)
406 			return -EINVAL;
407 		break;
408 	};
409 	return 0;
410 }
411 
412 /* Translate struct audit_rule_data to kernel's rule respresentation. */
413 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
414 					       size_t datasz)
415 {
416 	int err = 0;
417 	struct audit_entry *entry;
418 	void *bufp;
419 	size_t remain = datasz - sizeof(struct audit_rule_data);
420 	int i;
421 	char *str;
422 
423 	entry = audit_to_entry_common(data);
424 	if (IS_ERR(entry))
425 		goto exit_nofree;
426 
427 	bufp = data->buf;
428 	entry->rule.vers_ops = 2;
429 	for (i = 0; i < data->field_count; i++) {
430 		struct audit_field *f = &entry->rule.fields[i];
431 
432 		err = -EINVAL;
433 
434 		f->op = audit_to_op(data->fieldflags[i]);
435 		if (f->op == Audit_bad)
436 			goto exit_free;
437 
438 		f->type = data->fields[i];
439 		f->val = data->values[i];
440 
441 		/* Support legacy tests for a valid loginuid */
442 		if ((f->type == AUDIT_LOGINUID) && (f->val == AUDIT_UID_UNSET)) {
443 			f->type = AUDIT_LOGINUID_SET;
444 			f->val = 0;
445 			entry->rule.pflags |= AUDIT_LOGINUID_LEGACY;
446 		}
447 
448 		err = audit_field_valid(entry, f);
449 		if (err)
450 			goto exit_free;
451 
452 		err = -EINVAL;
453 		switch (f->type) {
454 		case AUDIT_LOGINUID:
455 		case AUDIT_UID:
456 		case AUDIT_EUID:
457 		case AUDIT_SUID:
458 		case AUDIT_FSUID:
459 		case AUDIT_OBJ_UID:
460 			f->uid = make_kuid(current_user_ns(), f->val);
461 			if (!uid_valid(f->uid))
462 				goto exit_free;
463 			break;
464 		case AUDIT_GID:
465 		case AUDIT_EGID:
466 		case AUDIT_SGID:
467 		case AUDIT_FSGID:
468 		case AUDIT_OBJ_GID:
469 			f->gid = make_kgid(current_user_ns(), f->val);
470 			if (!gid_valid(f->gid))
471 				goto exit_free;
472 			break;
473 		case AUDIT_ARCH:
474 			entry->rule.arch_f = f;
475 			break;
476 		case AUDIT_SUBJ_USER:
477 		case AUDIT_SUBJ_ROLE:
478 		case AUDIT_SUBJ_TYPE:
479 		case AUDIT_SUBJ_SEN:
480 		case AUDIT_SUBJ_CLR:
481 		case AUDIT_OBJ_USER:
482 		case AUDIT_OBJ_ROLE:
483 		case AUDIT_OBJ_TYPE:
484 		case AUDIT_OBJ_LEV_LOW:
485 		case AUDIT_OBJ_LEV_HIGH:
486 			str = audit_unpack_string(&bufp, &remain, f->val);
487 			if (IS_ERR(str))
488 				goto exit_free;
489 			entry->rule.buflen += f->val;
490 
491 			err = security_audit_rule_init(f->type, f->op, str,
492 						       (void **)&f->lsm_rule);
493 			/* Keep currently invalid fields around in case they
494 			 * become valid after a policy reload. */
495 			if (err == -EINVAL) {
496 				pr_warn("audit rule for LSM \'%s\' is invalid\n",
497 					str);
498 				err = 0;
499 			}
500 			if (err) {
501 				kfree(str);
502 				goto exit_free;
503 			} else
504 				f->lsm_str = str;
505 			break;
506 		case AUDIT_WATCH:
507 			str = audit_unpack_string(&bufp, &remain, f->val);
508 			if (IS_ERR(str))
509 				goto exit_free;
510 			entry->rule.buflen += f->val;
511 
512 			err = audit_to_watch(&entry->rule, str, f->val, f->op);
513 			if (err) {
514 				kfree(str);
515 				goto exit_free;
516 			}
517 			break;
518 		case AUDIT_DIR:
519 			str = audit_unpack_string(&bufp, &remain, f->val);
520 			if (IS_ERR(str))
521 				goto exit_free;
522 			entry->rule.buflen += f->val;
523 
524 			err = audit_make_tree(&entry->rule, str, f->op);
525 			kfree(str);
526 			if (err)
527 				goto exit_free;
528 			break;
529 		case AUDIT_INODE:
530 			err = audit_to_inode(&entry->rule, f);
531 			if (err)
532 				goto exit_free;
533 			break;
534 		case AUDIT_FILTERKEY:
535 			if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
536 				goto exit_free;
537 			str = audit_unpack_string(&bufp, &remain, f->val);
538 			if (IS_ERR(str))
539 				goto exit_free;
540 			entry->rule.buflen += f->val;
541 			entry->rule.filterkey = str;
542 			break;
543 		}
544 	}
545 
546 	if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
547 		entry->rule.inode_f = NULL;
548 
549 exit_nofree:
550 	return entry;
551 
552 exit_free:
553 	if (entry->rule.watch)
554 		audit_put_watch(entry->rule.watch); /* matches initial get */
555 	if (entry->rule.tree)
556 		audit_put_tree(entry->rule.tree); /* that's the temporary one */
557 	audit_free_rule(entry);
558 	return ERR_PTR(err);
559 }
560 
561 /* Pack a filter field's string representation into data block. */
562 static inline size_t audit_pack_string(void **bufp, const char *str)
563 {
564 	size_t len = strlen(str);
565 
566 	memcpy(*bufp, str, len);
567 	*bufp += len;
568 
569 	return len;
570 }
571 
572 /* Translate kernel rule respresentation to struct audit_rule_data. */
573 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
574 {
575 	struct audit_rule_data *data;
576 	void *bufp;
577 	int i;
578 
579 	data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
580 	if (unlikely(!data))
581 		return NULL;
582 	memset(data, 0, sizeof(*data));
583 
584 	data->flags = krule->flags | krule->listnr;
585 	data->action = krule->action;
586 	data->field_count = krule->field_count;
587 	bufp = data->buf;
588 	for (i = 0; i < data->field_count; i++) {
589 		struct audit_field *f = &krule->fields[i];
590 
591 		data->fields[i] = f->type;
592 		data->fieldflags[i] = audit_ops[f->op];
593 		switch(f->type) {
594 		case AUDIT_SUBJ_USER:
595 		case AUDIT_SUBJ_ROLE:
596 		case AUDIT_SUBJ_TYPE:
597 		case AUDIT_SUBJ_SEN:
598 		case AUDIT_SUBJ_CLR:
599 		case AUDIT_OBJ_USER:
600 		case AUDIT_OBJ_ROLE:
601 		case AUDIT_OBJ_TYPE:
602 		case AUDIT_OBJ_LEV_LOW:
603 		case AUDIT_OBJ_LEV_HIGH:
604 			data->buflen += data->values[i] =
605 				audit_pack_string(&bufp, f->lsm_str);
606 			break;
607 		case AUDIT_WATCH:
608 			data->buflen += data->values[i] =
609 				audit_pack_string(&bufp,
610 						  audit_watch_path(krule->watch));
611 			break;
612 		case AUDIT_DIR:
613 			data->buflen += data->values[i] =
614 				audit_pack_string(&bufp,
615 						  audit_tree_path(krule->tree));
616 			break;
617 		case AUDIT_FILTERKEY:
618 			data->buflen += data->values[i] =
619 				audit_pack_string(&bufp, krule->filterkey);
620 			break;
621 		case AUDIT_LOGINUID_SET:
622 			if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) {
623 				data->fields[i] = AUDIT_LOGINUID;
624 				data->values[i] = AUDIT_UID_UNSET;
625 				break;
626 			}
627 			/* fallthrough if set */
628 		default:
629 			data->values[i] = f->val;
630 		}
631 	}
632 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
633 
634 	return data;
635 }
636 
637 /* Compare two rules in kernel format.  Considered success if rules
638  * don't match. */
639 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
640 {
641 	int i;
642 
643 	if (a->flags != b->flags ||
644 	    a->pflags != b->pflags ||
645 	    a->listnr != b->listnr ||
646 	    a->action != b->action ||
647 	    a->field_count != b->field_count)
648 		return 1;
649 
650 	for (i = 0; i < a->field_count; i++) {
651 		if (a->fields[i].type != b->fields[i].type ||
652 		    a->fields[i].op != b->fields[i].op)
653 			return 1;
654 
655 		switch(a->fields[i].type) {
656 		case AUDIT_SUBJ_USER:
657 		case AUDIT_SUBJ_ROLE:
658 		case AUDIT_SUBJ_TYPE:
659 		case AUDIT_SUBJ_SEN:
660 		case AUDIT_SUBJ_CLR:
661 		case AUDIT_OBJ_USER:
662 		case AUDIT_OBJ_ROLE:
663 		case AUDIT_OBJ_TYPE:
664 		case AUDIT_OBJ_LEV_LOW:
665 		case AUDIT_OBJ_LEV_HIGH:
666 			if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
667 				return 1;
668 			break;
669 		case AUDIT_WATCH:
670 			if (strcmp(audit_watch_path(a->watch),
671 				   audit_watch_path(b->watch)))
672 				return 1;
673 			break;
674 		case AUDIT_DIR:
675 			if (strcmp(audit_tree_path(a->tree),
676 				   audit_tree_path(b->tree)))
677 				return 1;
678 			break;
679 		case AUDIT_FILTERKEY:
680 			/* both filterkeys exist based on above type compare */
681 			if (strcmp(a->filterkey, b->filterkey))
682 				return 1;
683 			break;
684 		case AUDIT_UID:
685 		case AUDIT_EUID:
686 		case AUDIT_SUID:
687 		case AUDIT_FSUID:
688 		case AUDIT_LOGINUID:
689 		case AUDIT_OBJ_UID:
690 			if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
691 				return 1;
692 			break;
693 		case AUDIT_GID:
694 		case AUDIT_EGID:
695 		case AUDIT_SGID:
696 		case AUDIT_FSGID:
697 		case AUDIT_OBJ_GID:
698 			if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
699 				return 1;
700 			break;
701 		default:
702 			if (a->fields[i].val != b->fields[i].val)
703 				return 1;
704 		}
705 	}
706 
707 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
708 		if (a->mask[i] != b->mask[i])
709 			return 1;
710 
711 	return 0;
712 }
713 
714 /* Duplicate LSM field information.  The lsm_rule is opaque, so must be
715  * re-initialized. */
716 static inline int audit_dupe_lsm_field(struct audit_field *df,
717 					   struct audit_field *sf)
718 {
719 	int ret = 0;
720 	char *lsm_str;
721 
722 	/* our own copy of lsm_str */
723 	lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
724 	if (unlikely(!lsm_str))
725 		return -ENOMEM;
726 	df->lsm_str = lsm_str;
727 
728 	/* our own (refreshed) copy of lsm_rule */
729 	ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
730 				       (void **)&df->lsm_rule);
731 	/* Keep currently invalid fields around in case they
732 	 * become valid after a policy reload. */
733 	if (ret == -EINVAL) {
734 		pr_warn("audit rule for LSM \'%s\' is invalid\n",
735 			df->lsm_str);
736 		ret = 0;
737 	}
738 
739 	return ret;
740 }
741 
742 /* Duplicate an audit rule.  This will be a deep copy with the exception
743  * of the watch - that pointer is carried over.  The LSM specific fields
744  * will be updated in the copy.  The point is to be able to replace the old
745  * rule with the new rule in the filterlist, then free the old rule.
746  * The rlist element is undefined; list manipulations are handled apart from
747  * the initial copy. */
748 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
749 {
750 	u32 fcount = old->field_count;
751 	struct audit_entry *entry;
752 	struct audit_krule *new;
753 	char *fk;
754 	int i, err = 0;
755 
756 	entry = audit_init_entry(fcount);
757 	if (unlikely(!entry))
758 		return ERR_PTR(-ENOMEM);
759 
760 	new = &entry->rule;
761 	new->vers_ops = old->vers_ops;
762 	new->flags = old->flags;
763 	new->pflags = old->pflags;
764 	new->listnr = old->listnr;
765 	new->action = old->action;
766 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
767 		new->mask[i] = old->mask[i];
768 	new->prio = old->prio;
769 	new->buflen = old->buflen;
770 	new->inode_f = old->inode_f;
771 	new->field_count = old->field_count;
772 
773 	/*
774 	 * note that we are OK with not refcounting here; audit_match_tree()
775 	 * never dereferences tree and we can't get false positives there
776 	 * since we'd have to have rule gone from the list *and* removed
777 	 * before the chunks found by lookup had been allocated, i.e. before
778 	 * the beginning of list scan.
779 	 */
780 	new->tree = old->tree;
781 	memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
782 
783 	/* deep copy this information, updating the lsm_rule fields, because
784 	 * the originals will all be freed when the old rule is freed. */
785 	for (i = 0; i < fcount; i++) {
786 		switch (new->fields[i].type) {
787 		case AUDIT_SUBJ_USER:
788 		case AUDIT_SUBJ_ROLE:
789 		case AUDIT_SUBJ_TYPE:
790 		case AUDIT_SUBJ_SEN:
791 		case AUDIT_SUBJ_CLR:
792 		case AUDIT_OBJ_USER:
793 		case AUDIT_OBJ_ROLE:
794 		case AUDIT_OBJ_TYPE:
795 		case AUDIT_OBJ_LEV_LOW:
796 		case AUDIT_OBJ_LEV_HIGH:
797 			err = audit_dupe_lsm_field(&new->fields[i],
798 						       &old->fields[i]);
799 			break;
800 		case AUDIT_FILTERKEY:
801 			fk = kstrdup(old->filterkey, GFP_KERNEL);
802 			if (unlikely(!fk))
803 				err = -ENOMEM;
804 			else
805 				new->filterkey = fk;
806 		}
807 		if (err) {
808 			audit_free_rule(entry);
809 			return ERR_PTR(err);
810 		}
811 	}
812 
813 	if (old->watch) {
814 		audit_get_watch(old->watch);
815 		new->watch = old->watch;
816 	}
817 
818 	return entry;
819 }
820 
821 /* Find an existing audit rule.
822  * Caller must hold audit_filter_mutex to prevent stale rule data. */
823 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
824 					   struct list_head **p)
825 {
826 	struct audit_entry *e, *found = NULL;
827 	struct list_head *list;
828 	int h;
829 
830 	if (entry->rule.inode_f) {
831 		h = audit_hash_ino(entry->rule.inode_f->val);
832 		*p = list = &audit_inode_hash[h];
833 	} else if (entry->rule.watch) {
834 		/* we don't know the inode number, so must walk entire hash */
835 		for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
836 			list = &audit_inode_hash[h];
837 			list_for_each_entry(e, list, list)
838 				if (!audit_compare_rule(&entry->rule, &e->rule)) {
839 					found = e;
840 					goto out;
841 				}
842 		}
843 		goto out;
844 	} else {
845 		*p = list = &audit_filter_list[entry->rule.listnr];
846 	}
847 
848 	list_for_each_entry(e, list, list)
849 		if (!audit_compare_rule(&entry->rule, &e->rule)) {
850 			found = e;
851 			goto out;
852 		}
853 
854 out:
855 	return found;
856 }
857 
858 static u64 prio_low = ~0ULL/2;
859 static u64 prio_high = ~0ULL/2 - 1;
860 
861 /* Add rule to given filterlist if not a duplicate. */
862 static inline int audit_add_rule(struct audit_entry *entry)
863 {
864 	struct audit_entry *e;
865 	struct audit_watch *watch = entry->rule.watch;
866 	struct audit_tree *tree = entry->rule.tree;
867 	struct list_head *list;
868 	int err;
869 #ifdef CONFIG_AUDITSYSCALL
870 	int dont_count = 0;
871 
872 	/* If either of these, don't count towards total */
873 	if (entry->rule.listnr == AUDIT_FILTER_USER ||
874 		entry->rule.listnr == AUDIT_FILTER_TYPE)
875 		dont_count = 1;
876 #endif
877 
878 	mutex_lock(&audit_filter_mutex);
879 	e = audit_find_rule(entry, &list);
880 	if (e) {
881 		mutex_unlock(&audit_filter_mutex);
882 		err = -EEXIST;
883 		/* normally audit_add_tree_rule() will free it on failure */
884 		if (tree)
885 			audit_put_tree(tree);
886 		goto error;
887 	}
888 
889 	if (watch) {
890 		/* audit_filter_mutex is dropped and re-taken during this call */
891 		err = audit_add_watch(&entry->rule, &list);
892 		if (err) {
893 			mutex_unlock(&audit_filter_mutex);
894 			/*
895 			 * normally audit_add_tree_rule() will free it
896 			 * on failure
897 			 */
898 			if (tree)
899 				audit_put_tree(tree);
900 			goto error;
901 		}
902 	}
903 	if (tree) {
904 		err = audit_add_tree_rule(&entry->rule);
905 		if (err) {
906 			mutex_unlock(&audit_filter_mutex);
907 			goto error;
908 		}
909 	}
910 
911 	entry->rule.prio = ~0ULL;
912 	if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
913 		if (entry->rule.flags & AUDIT_FILTER_PREPEND)
914 			entry->rule.prio = ++prio_high;
915 		else
916 			entry->rule.prio = --prio_low;
917 	}
918 
919 	if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
920 		list_add(&entry->rule.list,
921 			 &audit_rules_list[entry->rule.listnr]);
922 		list_add_rcu(&entry->list, list);
923 		entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
924 	} else {
925 		list_add_tail(&entry->rule.list,
926 			      &audit_rules_list[entry->rule.listnr]);
927 		list_add_tail_rcu(&entry->list, list);
928 	}
929 #ifdef CONFIG_AUDITSYSCALL
930 	if (!dont_count)
931 		audit_n_rules++;
932 
933 	if (!audit_match_signal(entry))
934 		audit_signals++;
935 #endif
936 	mutex_unlock(&audit_filter_mutex);
937 
938  	return 0;
939 
940 error:
941 	if (watch)
942 		audit_put_watch(watch); /* tmp watch, matches initial get */
943 	return err;
944 }
945 
946 /* Remove an existing rule from filterlist. */
947 static inline int audit_del_rule(struct audit_entry *entry)
948 {
949 	struct audit_entry  *e;
950 	struct audit_watch *watch = entry->rule.watch;
951 	struct audit_tree *tree = entry->rule.tree;
952 	struct list_head *list;
953 	int ret = 0;
954 #ifdef CONFIG_AUDITSYSCALL
955 	int dont_count = 0;
956 
957 	/* If either of these, don't count towards total */
958 	if (entry->rule.listnr == AUDIT_FILTER_USER ||
959 		entry->rule.listnr == AUDIT_FILTER_TYPE)
960 		dont_count = 1;
961 #endif
962 
963 	mutex_lock(&audit_filter_mutex);
964 	e = audit_find_rule(entry, &list);
965 	if (!e) {
966 		mutex_unlock(&audit_filter_mutex);
967 		ret = -ENOENT;
968 		goto out;
969 	}
970 
971 	if (e->rule.watch)
972 		audit_remove_watch_rule(&e->rule);
973 
974 	if (e->rule.tree)
975 		audit_remove_tree_rule(&e->rule);
976 
977 	list_del_rcu(&e->list);
978 	list_del(&e->rule.list);
979 	call_rcu(&e->rcu, audit_free_rule_rcu);
980 
981 #ifdef CONFIG_AUDITSYSCALL
982 	if (!dont_count)
983 		audit_n_rules--;
984 
985 	if (!audit_match_signal(entry))
986 		audit_signals--;
987 #endif
988 	mutex_unlock(&audit_filter_mutex);
989 
990 out:
991 	if (watch)
992 		audit_put_watch(watch); /* match initial get */
993 	if (tree)
994 		audit_put_tree(tree);	/* that's the temporary one */
995 
996 	return ret;
997 }
998 
999 /* List rules using struct audit_rule_data. */
1000 static void audit_list_rules(__u32 portid, int seq, struct sk_buff_head *q)
1001 {
1002 	struct sk_buff *skb;
1003 	struct audit_krule *r;
1004 	int i;
1005 
1006 	/* This is a blocking read, so use audit_filter_mutex instead of rcu
1007 	 * iterator to sync with list writers. */
1008 	for (i=0; i<AUDIT_NR_FILTERS; i++) {
1009 		list_for_each_entry(r, &audit_rules_list[i], list) {
1010 			struct audit_rule_data *data;
1011 
1012 			data = audit_krule_to_data(r);
1013 			if (unlikely(!data))
1014 				break;
1015 			skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES,
1016 					       0, 1, data,
1017 					       sizeof(*data) + data->buflen);
1018 			if (skb)
1019 				skb_queue_tail(q, skb);
1020 			kfree(data);
1021 		}
1022 	}
1023 	skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1024 	if (skb)
1025 		skb_queue_tail(q, skb);
1026 }
1027 
1028 /* Log rule additions and removals */
1029 static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
1030 {
1031 	struct audit_buffer *ab;
1032 	uid_t loginuid = from_kuid(&init_user_ns, audit_get_loginuid(current));
1033 	unsigned int sessionid = audit_get_sessionid(current);
1034 
1035 	if (!audit_enabled)
1036 		return;
1037 
1038 	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1039 	if (!ab)
1040 		return;
1041 	audit_log_format(ab, "auid=%u ses=%u" ,loginuid, sessionid);
1042 	audit_log_task_context(ab);
1043 	audit_log_format(ab, " op=");
1044 	audit_log_string(ab, action);
1045 	audit_log_key(ab, rule->filterkey);
1046 	audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1047 	audit_log_end(ab);
1048 }
1049 
1050 /**
1051  * audit_rule_change - apply all rules to the specified message type
1052  * @type: audit message type
1053  * @portid: target port id for netlink audit messages
1054  * @seq: netlink audit message sequence (serial) number
1055  * @data: payload data
1056  * @datasz: size of payload data
1057  */
1058 int audit_rule_change(int type, __u32 portid, int seq, void *data,
1059 			size_t datasz)
1060 {
1061 	int err = 0;
1062 	struct audit_entry *entry;
1063 
1064 	entry = audit_data_to_entry(data, datasz);
1065 	if (IS_ERR(entry))
1066 		return PTR_ERR(entry);
1067 
1068 	switch (type) {
1069 	case AUDIT_ADD_RULE:
1070 		err = audit_add_rule(entry);
1071 		audit_log_rule_change("add_rule", &entry->rule, !err);
1072 		break;
1073 	case AUDIT_DEL_RULE:
1074 		err = audit_del_rule(entry);
1075 		audit_log_rule_change("remove_rule", &entry->rule, !err);
1076 		break;
1077 	default:
1078 		err = -EINVAL;
1079 		WARN_ON(1);
1080 	}
1081 
1082 	if (err || type == AUDIT_DEL_RULE)
1083 		audit_free_rule(entry);
1084 
1085 	return err;
1086 }
1087 
1088 /**
1089  * audit_list_rules_send - list the audit rules
1090  * @request_skb: skb of request we are replying to (used to target the reply)
1091  * @seq: netlink audit message sequence (serial) number
1092  */
1093 int audit_list_rules_send(struct sk_buff *request_skb, int seq)
1094 {
1095 	u32 portid = NETLINK_CB(request_skb).portid;
1096 	struct net *net = sock_net(NETLINK_CB(request_skb).sk);
1097 	struct task_struct *tsk;
1098 	struct audit_netlink_list *dest;
1099 	int err = 0;
1100 
1101 	/* We can't just spew out the rules here because we might fill
1102 	 * the available socket buffer space and deadlock waiting for
1103 	 * auditctl to read from it... which isn't ever going to
1104 	 * happen if we're actually running in the context of auditctl
1105 	 * trying to _send_ the stuff */
1106 
1107 	dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1108 	if (!dest)
1109 		return -ENOMEM;
1110 	dest->net = get_net(net);
1111 	dest->portid = portid;
1112 	skb_queue_head_init(&dest->q);
1113 
1114 	mutex_lock(&audit_filter_mutex);
1115 	audit_list_rules(portid, seq, &dest->q);
1116 	mutex_unlock(&audit_filter_mutex);
1117 
1118 	tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1119 	if (IS_ERR(tsk)) {
1120 		skb_queue_purge(&dest->q);
1121 		kfree(dest);
1122 		err = PTR_ERR(tsk);
1123 	}
1124 
1125 	return err;
1126 }
1127 
1128 int audit_comparator(u32 left, u32 op, u32 right)
1129 {
1130 	switch (op) {
1131 	case Audit_equal:
1132 		return (left == right);
1133 	case Audit_not_equal:
1134 		return (left != right);
1135 	case Audit_lt:
1136 		return (left < right);
1137 	case Audit_le:
1138 		return (left <= right);
1139 	case Audit_gt:
1140 		return (left > right);
1141 	case Audit_ge:
1142 		return (left >= right);
1143 	case Audit_bitmask:
1144 		return (left & right);
1145 	case Audit_bittest:
1146 		return ((left & right) == right);
1147 	default:
1148 		BUG();
1149 		return 0;
1150 	}
1151 }
1152 
1153 int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1154 {
1155 	switch (op) {
1156 	case Audit_equal:
1157 		return uid_eq(left, right);
1158 	case Audit_not_equal:
1159 		return !uid_eq(left, right);
1160 	case Audit_lt:
1161 		return uid_lt(left, right);
1162 	case Audit_le:
1163 		return uid_lte(left, right);
1164 	case Audit_gt:
1165 		return uid_gt(left, right);
1166 	case Audit_ge:
1167 		return uid_gte(left, right);
1168 	case Audit_bitmask:
1169 	case Audit_bittest:
1170 	default:
1171 		BUG();
1172 		return 0;
1173 	}
1174 }
1175 
1176 int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1177 {
1178 	switch (op) {
1179 	case Audit_equal:
1180 		return gid_eq(left, right);
1181 	case Audit_not_equal:
1182 		return !gid_eq(left, right);
1183 	case Audit_lt:
1184 		return gid_lt(left, right);
1185 	case Audit_le:
1186 		return gid_lte(left, right);
1187 	case Audit_gt:
1188 		return gid_gt(left, right);
1189 	case Audit_ge:
1190 		return gid_gte(left, right);
1191 	case Audit_bitmask:
1192 	case Audit_bittest:
1193 	default:
1194 		BUG();
1195 		return 0;
1196 	}
1197 }
1198 
1199 /**
1200  * parent_len - find the length of the parent portion of a pathname
1201  * @path: pathname of which to determine length
1202  */
1203 int parent_len(const char *path)
1204 {
1205 	int plen;
1206 	const char *p;
1207 
1208 	plen = strlen(path);
1209 
1210 	if (plen == 0)
1211 		return plen;
1212 
1213 	/* disregard trailing slashes */
1214 	p = path + plen - 1;
1215 	while ((*p == '/') && (p > path))
1216 		p--;
1217 
1218 	/* walk backward until we find the next slash or hit beginning */
1219 	while ((*p != '/') && (p > path))
1220 		p--;
1221 
1222 	/* did we find a slash? Then increment to include it in path */
1223 	if (*p == '/')
1224 		p++;
1225 
1226 	return p - path;
1227 }
1228 
1229 /**
1230  * audit_compare_dname_path - compare given dentry name with last component in
1231  * 			      given path. Return of 0 indicates a match.
1232  * @dname:	dentry name that we're comparing
1233  * @path:	full pathname that we're comparing
1234  * @parentlen:	length of the parent if known. Passing in AUDIT_NAME_FULL
1235  * 		here indicates that we must compute this value.
1236  */
1237 int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
1238 {
1239 	int dlen, pathlen;
1240 	const char *p;
1241 
1242 	dlen = strlen(dname);
1243 	pathlen = strlen(path);
1244 	if (pathlen < dlen)
1245 		return 1;
1246 
1247 	parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1248 	if (pathlen - parentlen != dlen)
1249 		return 1;
1250 
1251 	p = path + parentlen;
1252 
1253 	return strncmp(p, dname, dlen);
1254 }
1255 
1256 static int audit_filter_user_rules(struct audit_krule *rule, int type,
1257 				   enum audit_state *state)
1258 {
1259 	int i;
1260 
1261 	for (i = 0; i < rule->field_count; i++) {
1262 		struct audit_field *f = &rule->fields[i];
1263 		pid_t pid;
1264 		int result = 0;
1265 		u32 sid;
1266 
1267 		switch (f->type) {
1268 		case AUDIT_PID:
1269 			pid = task_pid_nr(current);
1270 			result = audit_comparator(pid, f->op, f->val);
1271 			break;
1272 		case AUDIT_UID:
1273 			result = audit_uid_comparator(current_uid(), f->op, f->uid);
1274 			break;
1275 		case AUDIT_GID:
1276 			result = audit_gid_comparator(current_gid(), f->op, f->gid);
1277 			break;
1278 		case AUDIT_LOGINUID:
1279 			result = audit_uid_comparator(audit_get_loginuid(current),
1280 						  f->op, f->uid);
1281 			break;
1282 		case AUDIT_LOGINUID_SET:
1283 			result = audit_comparator(audit_loginuid_set(current),
1284 						  f->op, f->val);
1285 			break;
1286 		case AUDIT_MSGTYPE:
1287 			result = audit_comparator(type, f->op, f->val);
1288 			break;
1289 		case AUDIT_SUBJ_USER:
1290 		case AUDIT_SUBJ_ROLE:
1291 		case AUDIT_SUBJ_TYPE:
1292 		case AUDIT_SUBJ_SEN:
1293 		case AUDIT_SUBJ_CLR:
1294 			if (f->lsm_rule) {
1295 				security_task_getsecid(current, &sid);
1296 				result = security_audit_rule_match(sid,
1297 								   f->type,
1298 								   f->op,
1299 								   f->lsm_rule,
1300 								   NULL);
1301 			}
1302 			break;
1303 		}
1304 
1305 		if (!result)
1306 			return 0;
1307 	}
1308 	switch (rule->action) {
1309 	case AUDIT_NEVER:    *state = AUDIT_DISABLED;	    break;
1310 	case AUDIT_ALWAYS:   *state = AUDIT_RECORD_CONTEXT; break;
1311 	}
1312 	return 1;
1313 }
1314 
1315 int audit_filter_user(int type)
1316 {
1317 	enum audit_state state = AUDIT_DISABLED;
1318 	struct audit_entry *e;
1319 	int rc, ret;
1320 
1321 	ret = 1; /* Audit by default */
1322 
1323 	rcu_read_lock();
1324 	list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1325 		rc = audit_filter_user_rules(&e->rule, type, &state);
1326 		if (rc) {
1327 			if (rc > 0 && state == AUDIT_DISABLED)
1328 				ret = 0;
1329 			break;
1330 		}
1331 	}
1332 	rcu_read_unlock();
1333 
1334 	return ret;
1335 }
1336 
1337 int audit_filter_type(int type)
1338 {
1339 	struct audit_entry *e;
1340 	int result = 0;
1341 
1342 	rcu_read_lock();
1343 	if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1344 		goto unlock_and_return;
1345 
1346 	list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1347 				list) {
1348 		int i;
1349 		for (i = 0; i < e->rule.field_count; i++) {
1350 			struct audit_field *f = &e->rule.fields[i];
1351 			if (f->type == AUDIT_MSGTYPE) {
1352 				result = audit_comparator(type, f->op, f->val);
1353 				if (!result)
1354 					break;
1355 			}
1356 		}
1357 		if (result)
1358 			goto unlock_and_return;
1359 	}
1360 unlock_and_return:
1361 	rcu_read_unlock();
1362 	return result;
1363 }
1364 
1365 static int update_lsm_rule(struct audit_krule *r)
1366 {
1367 	struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1368 	struct audit_entry *nentry;
1369 	int err = 0;
1370 
1371 	if (!security_audit_rule_known(r))
1372 		return 0;
1373 
1374 	nentry = audit_dupe_rule(r);
1375 	if (IS_ERR(nentry)) {
1376 		/* save the first error encountered for the
1377 		 * return value */
1378 		err = PTR_ERR(nentry);
1379 		audit_panic("error updating LSM filters");
1380 		if (r->watch)
1381 			list_del(&r->rlist);
1382 		list_del_rcu(&entry->list);
1383 		list_del(&r->list);
1384 	} else {
1385 		if (r->watch || r->tree)
1386 			list_replace_init(&r->rlist, &nentry->rule.rlist);
1387 		list_replace_rcu(&entry->list, &nentry->list);
1388 		list_replace(&r->list, &nentry->rule.list);
1389 	}
1390 	call_rcu(&entry->rcu, audit_free_rule_rcu);
1391 
1392 	return err;
1393 }
1394 
1395 /* This function will re-initialize the lsm_rule field of all applicable rules.
1396  * It will traverse the filter lists serarching for rules that contain LSM
1397  * specific filter fields.  When such a rule is found, it is copied, the
1398  * LSM field is re-initialized, and the old rule is replaced with the
1399  * updated rule. */
1400 int audit_update_lsm_rules(void)
1401 {
1402 	struct audit_krule *r, *n;
1403 	int i, err = 0;
1404 
1405 	/* audit_filter_mutex synchronizes the writers */
1406 	mutex_lock(&audit_filter_mutex);
1407 
1408 	for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1409 		list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1410 			int res = update_lsm_rule(r);
1411 			if (!err)
1412 				err = res;
1413 		}
1414 	}
1415 	mutex_unlock(&audit_filter_mutex);
1416 
1417 	return err;
1418 }
1419