xref: /openbmc/linux/kernel/auditfilter.c (revision b34e08d5)
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 inline void audit_free_rule(struct audit_entry *e)
75 {
76 	int i;
77 	struct audit_krule *erule = &e->rule;
78 
79 	/* some rules don't have associated watches */
80 	if (erule->watch)
81 		audit_put_watch(erule->watch);
82 	if (erule->fields)
83 		for (i = 0; i < erule->field_count; i++) {
84 			struct audit_field *f = &erule->fields[i];
85 			kfree(f->lsm_str);
86 			security_audit_rule_free(f->lsm_rule);
87 		}
88 	kfree(erule->fields);
89 	kfree(erule->filterkey);
90 	kfree(e);
91 }
92 
93 void audit_free_rule_rcu(struct rcu_head *head)
94 {
95 	struct audit_entry *e = container_of(head, struct audit_entry, rcu);
96 	audit_free_rule(e);
97 }
98 
99 /* Initialize an audit filterlist entry. */
100 static inline struct audit_entry *audit_init_entry(u32 field_count)
101 {
102 	struct audit_entry *entry;
103 	struct audit_field *fields;
104 
105 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
106 	if (unlikely(!entry))
107 		return NULL;
108 
109 	fields = kzalloc(sizeof(*fields) * field_count, GFP_KERNEL);
110 	if (unlikely(!fields)) {
111 		kfree(entry);
112 		return NULL;
113 	}
114 	entry->rule.fields = fields;
115 
116 	return entry;
117 }
118 
119 /* Unpack a filter field's string representation from user-space
120  * buffer. */
121 char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
122 {
123 	char *str;
124 
125 	if (!*bufp || (len == 0) || (len > *remain))
126 		return ERR_PTR(-EINVAL);
127 
128 	/* Of the currently implemented string fields, PATH_MAX
129 	 * defines the longest valid length.
130 	 */
131 	if (len > PATH_MAX)
132 		return ERR_PTR(-ENAMETOOLONG);
133 
134 	str = kmalloc(len + 1, GFP_KERNEL);
135 	if (unlikely(!str))
136 		return ERR_PTR(-ENOMEM);
137 
138 	memcpy(str, *bufp, len);
139 	str[len] = 0;
140 	*bufp += len;
141 	*remain -= len;
142 
143 	return str;
144 }
145 
146 /* Translate an inode field to kernel respresentation. */
147 static inline int audit_to_inode(struct audit_krule *krule,
148 				 struct audit_field *f)
149 {
150 	if (krule->listnr != AUDIT_FILTER_EXIT ||
151 	    krule->watch || krule->inode_f || krule->tree ||
152 	    (f->op != Audit_equal && f->op != Audit_not_equal))
153 		return -EINVAL;
154 
155 	krule->inode_f = f;
156 	return 0;
157 }
158 
159 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
160 
161 int __init audit_register_class(int class, unsigned *list)
162 {
163 	__u32 *p = kzalloc(AUDIT_BITMASK_SIZE * sizeof(__u32), GFP_KERNEL);
164 	if (!p)
165 		return -ENOMEM;
166 	while (*list != ~0U) {
167 		unsigned n = *list++;
168 		if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
169 			kfree(p);
170 			return -EINVAL;
171 		}
172 		p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
173 	}
174 	if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
175 		kfree(p);
176 		return -EINVAL;
177 	}
178 	classes[class] = p;
179 	return 0;
180 }
181 
182 int audit_match_class(int class, unsigned syscall)
183 {
184 	if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
185 		return 0;
186 	if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
187 		return 0;
188 	return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
189 }
190 
191 #ifdef CONFIG_AUDITSYSCALL
192 static inline int audit_match_class_bits(int class, u32 *mask)
193 {
194 	int i;
195 
196 	if (classes[class]) {
197 		for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
198 			if (mask[i] & classes[class][i])
199 				return 0;
200 	}
201 	return 1;
202 }
203 
204 static int audit_match_signal(struct audit_entry *entry)
205 {
206 	struct audit_field *arch = entry->rule.arch_f;
207 
208 	if (!arch) {
209 		/* When arch is unspecified, we must check both masks on biarch
210 		 * as syscall number alone is ambiguous. */
211 		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
212 					       entry->rule.mask) &&
213 			audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
214 					       entry->rule.mask));
215 	}
216 
217 	switch(audit_classify_arch(arch->val)) {
218 	case 0: /* native */
219 		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
220 					       entry->rule.mask));
221 	case 1: /* 32bit on biarch */
222 		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
223 					       entry->rule.mask));
224 	default:
225 		return 1;
226 	}
227 }
228 #endif
229 
230 /* Common user-space to kernel rule translation. */
231 static inline struct audit_entry *audit_to_entry_common(struct audit_rule_data *rule)
232 {
233 	unsigned listnr;
234 	struct audit_entry *entry;
235 	int i, err;
236 
237 	err = -EINVAL;
238 	listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
239 	switch(listnr) {
240 	default:
241 		goto exit_err;
242 #ifdef CONFIG_AUDITSYSCALL
243 	case AUDIT_FILTER_ENTRY:
244 		if (rule->action == AUDIT_ALWAYS)
245 			goto exit_err;
246 	case AUDIT_FILTER_EXIT:
247 	case AUDIT_FILTER_TASK:
248 #endif
249 	case AUDIT_FILTER_USER:
250 	case AUDIT_FILTER_TYPE:
251 		;
252 	}
253 	if (unlikely(rule->action == AUDIT_POSSIBLE)) {
254 		pr_err("AUDIT_POSSIBLE is deprecated\n");
255 		goto exit_err;
256 	}
257 	if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
258 		goto exit_err;
259 	if (rule->field_count > AUDIT_MAX_FIELDS)
260 		goto exit_err;
261 
262 	err = -ENOMEM;
263 	entry = audit_init_entry(rule->field_count);
264 	if (!entry)
265 		goto exit_err;
266 
267 	entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
268 	entry->rule.listnr = listnr;
269 	entry->rule.action = rule->action;
270 	entry->rule.field_count = rule->field_count;
271 
272 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
273 		entry->rule.mask[i] = rule->mask[i];
274 
275 	for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
276 		int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
277 		__u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
278 		__u32 *class;
279 
280 		if (!(*p & AUDIT_BIT(bit)))
281 			continue;
282 		*p &= ~AUDIT_BIT(bit);
283 		class = classes[i];
284 		if (class) {
285 			int j;
286 			for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
287 				entry->rule.mask[j] |= class[j];
288 		}
289 	}
290 
291 	return entry;
292 
293 exit_err:
294 	return ERR_PTR(err);
295 }
296 
297 static u32 audit_ops[] =
298 {
299 	[Audit_equal] = AUDIT_EQUAL,
300 	[Audit_not_equal] = AUDIT_NOT_EQUAL,
301 	[Audit_bitmask] = AUDIT_BIT_MASK,
302 	[Audit_bittest] = AUDIT_BIT_TEST,
303 	[Audit_lt] = AUDIT_LESS_THAN,
304 	[Audit_gt] = AUDIT_GREATER_THAN,
305 	[Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
306 	[Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
307 };
308 
309 static u32 audit_to_op(u32 op)
310 {
311 	u32 n;
312 	for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
313 		;
314 	return n;
315 }
316 
317 /* check if an audit field is valid */
318 static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
319 {
320 	switch(f->type) {
321 	case AUDIT_MSGTYPE:
322 		if (entry->rule.listnr != AUDIT_FILTER_TYPE &&
323 		    entry->rule.listnr != AUDIT_FILTER_USER)
324 			return -EINVAL;
325 		break;
326 	};
327 
328 	switch(f->type) {
329 	default:
330 		return -EINVAL;
331 	case AUDIT_UID:
332 	case AUDIT_EUID:
333 	case AUDIT_SUID:
334 	case AUDIT_FSUID:
335 	case AUDIT_LOGINUID:
336 	case AUDIT_OBJ_UID:
337 	case AUDIT_GID:
338 	case AUDIT_EGID:
339 	case AUDIT_SGID:
340 	case AUDIT_FSGID:
341 	case AUDIT_OBJ_GID:
342 	case AUDIT_PID:
343 	case AUDIT_PERS:
344 	case AUDIT_MSGTYPE:
345 	case AUDIT_PPID:
346 	case AUDIT_DEVMAJOR:
347 	case AUDIT_DEVMINOR:
348 	case AUDIT_EXIT:
349 	case AUDIT_SUCCESS:
350 	case AUDIT_INODE:
351 		/* bit ops are only useful on syscall args */
352 		if (f->op == Audit_bitmask || f->op == Audit_bittest)
353 			return -EINVAL;
354 		break;
355 	case AUDIT_ARG0:
356 	case AUDIT_ARG1:
357 	case AUDIT_ARG2:
358 	case AUDIT_ARG3:
359 	case AUDIT_SUBJ_USER:
360 	case AUDIT_SUBJ_ROLE:
361 	case AUDIT_SUBJ_TYPE:
362 	case AUDIT_SUBJ_SEN:
363 	case AUDIT_SUBJ_CLR:
364 	case AUDIT_OBJ_USER:
365 	case AUDIT_OBJ_ROLE:
366 	case AUDIT_OBJ_TYPE:
367 	case AUDIT_OBJ_LEV_LOW:
368 	case AUDIT_OBJ_LEV_HIGH:
369 	case AUDIT_WATCH:
370 	case AUDIT_DIR:
371 	case AUDIT_FILTERKEY:
372 		break;
373 	case AUDIT_LOGINUID_SET:
374 		if ((f->val != 0) && (f->val != 1))
375 			return -EINVAL;
376 	/* FALL THROUGH */
377 	case AUDIT_ARCH:
378 		if (f->op != Audit_not_equal && f->op != Audit_equal)
379 			return -EINVAL;
380 		break;
381 	case AUDIT_PERM:
382 		if (f->val & ~15)
383 			return -EINVAL;
384 		break;
385 	case AUDIT_FILETYPE:
386 		if (f->val & ~S_IFMT)
387 			return -EINVAL;
388 		break;
389 	case AUDIT_FIELD_COMPARE:
390 		if (f->val > AUDIT_MAX_FIELD_COMPARE)
391 			return -EINVAL;
392 		break;
393 	};
394 	return 0;
395 }
396 
397 /* Translate struct audit_rule_data to kernel's rule respresentation. */
398 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
399 					       size_t datasz)
400 {
401 	int err = 0;
402 	struct audit_entry *entry;
403 	void *bufp;
404 	size_t remain = datasz - sizeof(struct audit_rule_data);
405 	int i;
406 	char *str;
407 
408 	entry = audit_to_entry_common(data);
409 	if (IS_ERR(entry))
410 		goto exit_nofree;
411 
412 	bufp = data->buf;
413 	entry->rule.vers_ops = 2;
414 	for (i = 0; i < data->field_count; i++) {
415 		struct audit_field *f = &entry->rule.fields[i];
416 
417 		err = -EINVAL;
418 
419 		f->op = audit_to_op(data->fieldflags[i]);
420 		if (f->op == Audit_bad)
421 			goto exit_free;
422 
423 		f->type = data->fields[i];
424 		f->val = data->values[i];
425 		f->uid = INVALID_UID;
426 		f->gid = INVALID_GID;
427 		f->lsm_str = NULL;
428 		f->lsm_rule = NULL;
429 
430 		/* Support legacy tests for a valid loginuid */
431 		if ((f->type == AUDIT_LOGINUID) && (f->val == AUDIT_UID_UNSET)) {
432 			f->type = AUDIT_LOGINUID_SET;
433 			f->val = 0;
434 		}
435 
436 		if ((f->type == AUDIT_PID) || (f->type == AUDIT_PPID)) {
437 			struct pid *pid;
438 			rcu_read_lock();
439 			pid = find_vpid(f->val);
440 			if (!pid) {
441 				rcu_read_unlock();
442 				err = -ESRCH;
443 				goto exit_free;
444 			}
445 			f->val = pid_nr(pid);
446 			rcu_read_unlock();
447 		}
448 
449 		err = audit_field_valid(entry, f);
450 		if (err)
451 			goto exit_free;
452 
453 		err = -EINVAL;
454 		switch (f->type) {
455 		case AUDIT_LOGINUID:
456 		case AUDIT_UID:
457 		case AUDIT_EUID:
458 		case AUDIT_SUID:
459 		case AUDIT_FSUID:
460 		case AUDIT_OBJ_UID:
461 			f->uid = make_kuid(current_user_ns(), f->val);
462 			if (!uid_valid(f->uid))
463 				goto exit_free;
464 			break;
465 		case AUDIT_GID:
466 		case AUDIT_EGID:
467 		case AUDIT_SGID:
468 		case AUDIT_FSGID:
469 		case AUDIT_OBJ_GID:
470 			f->gid = make_kgid(current_user_ns(), f->val);
471 			if (!gid_valid(f->gid))
472 				goto exit_free;
473 			break;
474 		case AUDIT_ARCH:
475 			entry->rule.arch_f = f;
476 			break;
477 		case AUDIT_SUBJ_USER:
478 		case AUDIT_SUBJ_ROLE:
479 		case AUDIT_SUBJ_TYPE:
480 		case AUDIT_SUBJ_SEN:
481 		case AUDIT_SUBJ_CLR:
482 		case AUDIT_OBJ_USER:
483 		case AUDIT_OBJ_ROLE:
484 		case AUDIT_OBJ_TYPE:
485 		case AUDIT_OBJ_LEV_LOW:
486 		case AUDIT_OBJ_LEV_HIGH:
487 			str = audit_unpack_string(&bufp, &remain, f->val);
488 			if (IS_ERR(str))
489 				goto exit_free;
490 			entry->rule.buflen += f->val;
491 
492 			err = security_audit_rule_init(f->type, f->op, str,
493 						       (void **)&f->lsm_rule);
494 			/* Keep currently invalid fields around in case they
495 			 * become valid after a policy reload. */
496 			if (err == -EINVAL) {
497 				pr_warn("audit rule for LSM \'%s\' is invalid\n",
498 					str);
499 				err = 0;
500 			}
501 			if (err) {
502 				kfree(str);
503 				goto exit_free;
504 			} else
505 				f->lsm_str = str;
506 			break;
507 		case AUDIT_WATCH:
508 			str = audit_unpack_string(&bufp, &remain, f->val);
509 			if (IS_ERR(str))
510 				goto exit_free;
511 			entry->rule.buflen += f->val;
512 
513 			err = audit_to_watch(&entry->rule, str, f->val, f->op);
514 			if (err) {
515 				kfree(str);
516 				goto exit_free;
517 			}
518 			break;
519 		case AUDIT_DIR:
520 			str = audit_unpack_string(&bufp, &remain, f->val);
521 			if (IS_ERR(str))
522 				goto exit_free;
523 			entry->rule.buflen += f->val;
524 
525 			err = audit_make_tree(&entry->rule, str, f->op);
526 			kfree(str);
527 			if (err)
528 				goto exit_free;
529 			break;
530 		case AUDIT_INODE:
531 			err = audit_to_inode(&entry->rule, f);
532 			if (err)
533 				goto exit_free;
534 			break;
535 		case AUDIT_FILTERKEY:
536 			if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
537 				goto exit_free;
538 			str = audit_unpack_string(&bufp, &remain, f->val);
539 			if (IS_ERR(str))
540 				goto exit_free;
541 			entry->rule.buflen += f->val;
542 			entry->rule.filterkey = str;
543 			break;
544 		}
545 	}
546 
547 	if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
548 		entry->rule.inode_f = NULL;
549 
550 exit_nofree:
551 	return entry;
552 
553 exit_free:
554 	if (entry->rule.watch)
555 		audit_put_watch(entry->rule.watch); /* matches initial get */
556 	if (entry->rule.tree)
557 		audit_put_tree(entry->rule.tree); /* that's the temporary one */
558 	audit_free_rule(entry);
559 	return ERR_PTR(err);
560 }
561 
562 /* Pack a filter field's string representation into data block. */
563 static inline size_t audit_pack_string(void **bufp, const char *str)
564 {
565 	size_t len = strlen(str);
566 
567 	memcpy(*bufp, str, len);
568 	*bufp += len;
569 
570 	return len;
571 }
572 
573 /* Translate kernel rule respresentation to struct audit_rule_data. */
574 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
575 {
576 	struct audit_rule_data *data;
577 	void *bufp;
578 	int i;
579 
580 	data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
581 	if (unlikely(!data))
582 		return NULL;
583 	memset(data, 0, sizeof(*data));
584 
585 	data->flags = krule->flags | krule->listnr;
586 	data->action = krule->action;
587 	data->field_count = krule->field_count;
588 	bufp = data->buf;
589 	for (i = 0; i < data->field_count; i++) {
590 		struct audit_field *f = &krule->fields[i];
591 
592 		data->fields[i] = f->type;
593 		data->fieldflags[i] = audit_ops[f->op];
594 		switch(f->type) {
595 		case AUDIT_SUBJ_USER:
596 		case AUDIT_SUBJ_ROLE:
597 		case AUDIT_SUBJ_TYPE:
598 		case AUDIT_SUBJ_SEN:
599 		case AUDIT_SUBJ_CLR:
600 		case AUDIT_OBJ_USER:
601 		case AUDIT_OBJ_ROLE:
602 		case AUDIT_OBJ_TYPE:
603 		case AUDIT_OBJ_LEV_LOW:
604 		case AUDIT_OBJ_LEV_HIGH:
605 			data->buflen += data->values[i] =
606 				audit_pack_string(&bufp, f->lsm_str);
607 			break;
608 		case AUDIT_WATCH:
609 			data->buflen += data->values[i] =
610 				audit_pack_string(&bufp,
611 						  audit_watch_path(krule->watch));
612 			break;
613 		case AUDIT_DIR:
614 			data->buflen += data->values[i] =
615 				audit_pack_string(&bufp,
616 						  audit_tree_path(krule->tree));
617 			break;
618 		case AUDIT_FILTERKEY:
619 			data->buflen += data->values[i] =
620 				audit_pack_string(&bufp, krule->filterkey);
621 			break;
622 		default:
623 			data->values[i] = f->val;
624 		}
625 	}
626 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
627 
628 	return data;
629 }
630 
631 /* Compare two rules in kernel format.  Considered success if rules
632  * don't match. */
633 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
634 {
635 	int i;
636 
637 	if (a->flags != b->flags ||
638 	    a->listnr != b->listnr ||
639 	    a->action != b->action ||
640 	    a->field_count != b->field_count)
641 		return 1;
642 
643 	for (i = 0; i < a->field_count; i++) {
644 		if (a->fields[i].type != b->fields[i].type ||
645 		    a->fields[i].op != b->fields[i].op)
646 			return 1;
647 
648 		switch(a->fields[i].type) {
649 		case AUDIT_SUBJ_USER:
650 		case AUDIT_SUBJ_ROLE:
651 		case AUDIT_SUBJ_TYPE:
652 		case AUDIT_SUBJ_SEN:
653 		case AUDIT_SUBJ_CLR:
654 		case AUDIT_OBJ_USER:
655 		case AUDIT_OBJ_ROLE:
656 		case AUDIT_OBJ_TYPE:
657 		case AUDIT_OBJ_LEV_LOW:
658 		case AUDIT_OBJ_LEV_HIGH:
659 			if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
660 				return 1;
661 			break;
662 		case AUDIT_WATCH:
663 			if (strcmp(audit_watch_path(a->watch),
664 				   audit_watch_path(b->watch)))
665 				return 1;
666 			break;
667 		case AUDIT_DIR:
668 			if (strcmp(audit_tree_path(a->tree),
669 				   audit_tree_path(b->tree)))
670 				return 1;
671 			break;
672 		case AUDIT_FILTERKEY:
673 			/* both filterkeys exist based on above type compare */
674 			if (strcmp(a->filterkey, b->filterkey))
675 				return 1;
676 			break;
677 		case AUDIT_UID:
678 		case AUDIT_EUID:
679 		case AUDIT_SUID:
680 		case AUDIT_FSUID:
681 		case AUDIT_LOGINUID:
682 		case AUDIT_OBJ_UID:
683 			if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
684 				return 1;
685 			break;
686 		case AUDIT_GID:
687 		case AUDIT_EGID:
688 		case AUDIT_SGID:
689 		case AUDIT_FSGID:
690 		case AUDIT_OBJ_GID:
691 			if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
692 				return 1;
693 			break;
694 		default:
695 			if (a->fields[i].val != b->fields[i].val)
696 				return 1;
697 		}
698 	}
699 
700 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
701 		if (a->mask[i] != b->mask[i])
702 			return 1;
703 
704 	return 0;
705 }
706 
707 /* Duplicate LSM field information.  The lsm_rule is opaque, so must be
708  * re-initialized. */
709 static inline int audit_dupe_lsm_field(struct audit_field *df,
710 					   struct audit_field *sf)
711 {
712 	int ret = 0;
713 	char *lsm_str;
714 
715 	/* our own copy of lsm_str */
716 	lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
717 	if (unlikely(!lsm_str))
718 		return -ENOMEM;
719 	df->lsm_str = lsm_str;
720 
721 	/* our own (refreshed) copy of lsm_rule */
722 	ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
723 				       (void **)&df->lsm_rule);
724 	/* Keep currently invalid fields around in case they
725 	 * become valid after a policy reload. */
726 	if (ret == -EINVAL) {
727 		pr_warn("audit rule for LSM \'%s\' is invalid\n",
728 			df->lsm_str);
729 		ret = 0;
730 	}
731 
732 	return ret;
733 }
734 
735 /* Duplicate an audit rule.  This will be a deep copy with the exception
736  * of the watch - that pointer is carried over.  The LSM specific fields
737  * will be updated in the copy.  The point is to be able to replace the old
738  * rule with the new rule in the filterlist, then free the old rule.
739  * The rlist element is undefined; list manipulations are handled apart from
740  * the initial copy. */
741 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
742 {
743 	u32 fcount = old->field_count;
744 	struct audit_entry *entry;
745 	struct audit_krule *new;
746 	char *fk;
747 	int i, err = 0;
748 
749 	entry = audit_init_entry(fcount);
750 	if (unlikely(!entry))
751 		return ERR_PTR(-ENOMEM);
752 
753 	new = &entry->rule;
754 	new->vers_ops = old->vers_ops;
755 	new->flags = old->flags;
756 	new->listnr = old->listnr;
757 	new->action = old->action;
758 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
759 		new->mask[i] = old->mask[i];
760 	new->prio = old->prio;
761 	new->buflen = old->buflen;
762 	new->inode_f = old->inode_f;
763 	new->field_count = old->field_count;
764 
765 	/*
766 	 * note that we are OK with not refcounting here; audit_match_tree()
767 	 * never dereferences tree and we can't get false positives there
768 	 * since we'd have to have rule gone from the list *and* removed
769 	 * before the chunks found by lookup had been allocated, i.e. before
770 	 * the beginning of list scan.
771 	 */
772 	new->tree = old->tree;
773 	memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
774 
775 	/* deep copy this information, updating the lsm_rule fields, because
776 	 * the originals will all be freed when the old rule is freed. */
777 	for (i = 0; i < fcount; i++) {
778 		switch (new->fields[i].type) {
779 		case AUDIT_SUBJ_USER:
780 		case AUDIT_SUBJ_ROLE:
781 		case AUDIT_SUBJ_TYPE:
782 		case AUDIT_SUBJ_SEN:
783 		case AUDIT_SUBJ_CLR:
784 		case AUDIT_OBJ_USER:
785 		case AUDIT_OBJ_ROLE:
786 		case AUDIT_OBJ_TYPE:
787 		case AUDIT_OBJ_LEV_LOW:
788 		case AUDIT_OBJ_LEV_HIGH:
789 			err = audit_dupe_lsm_field(&new->fields[i],
790 						       &old->fields[i]);
791 			break;
792 		case AUDIT_FILTERKEY:
793 			fk = kstrdup(old->filterkey, GFP_KERNEL);
794 			if (unlikely(!fk))
795 				err = -ENOMEM;
796 			else
797 				new->filterkey = fk;
798 		}
799 		if (err) {
800 			audit_free_rule(entry);
801 			return ERR_PTR(err);
802 		}
803 	}
804 
805 	if (old->watch) {
806 		audit_get_watch(old->watch);
807 		new->watch = old->watch;
808 	}
809 
810 	return entry;
811 }
812 
813 /* Find an existing audit rule.
814  * Caller must hold audit_filter_mutex to prevent stale rule data. */
815 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
816 					   struct list_head **p)
817 {
818 	struct audit_entry *e, *found = NULL;
819 	struct list_head *list;
820 	int h;
821 
822 	if (entry->rule.inode_f) {
823 		h = audit_hash_ino(entry->rule.inode_f->val);
824 		*p = list = &audit_inode_hash[h];
825 	} else if (entry->rule.watch) {
826 		/* we don't know the inode number, so must walk entire hash */
827 		for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
828 			list = &audit_inode_hash[h];
829 			list_for_each_entry(e, list, list)
830 				if (!audit_compare_rule(&entry->rule, &e->rule)) {
831 					found = e;
832 					goto out;
833 				}
834 		}
835 		goto out;
836 	} else {
837 		*p = list = &audit_filter_list[entry->rule.listnr];
838 	}
839 
840 	list_for_each_entry(e, list, list)
841 		if (!audit_compare_rule(&entry->rule, &e->rule)) {
842 			found = e;
843 			goto out;
844 		}
845 
846 out:
847 	return found;
848 }
849 
850 static u64 prio_low = ~0ULL/2;
851 static u64 prio_high = ~0ULL/2 - 1;
852 
853 /* Add rule to given filterlist if not a duplicate. */
854 static inline int audit_add_rule(struct audit_entry *entry)
855 {
856 	struct audit_entry *e;
857 	struct audit_watch *watch = entry->rule.watch;
858 	struct audit_tree *tree = entry->rule.tree;
859 	struct list_head *list;
860 	int err;
861 #ifdef CONFIG_AUDITSYSCALL
862 	int dont_count = 0;
863 
864 	/* If either of these, don't count towards total */
865 	if (entry->rule.listnr == AUDIT_FILTER_USER ||
866 		entry->rule.listnr == AUDIT_FILTER_TYPE)
867 		dont_count = 1;
868 #endif
869 
870 	mutex_lock(&audit_filter_mutex);
871 	e = audit_find_rule(entry, &list);
872 	if (e) {
873 		mutex_unlock(&audit_filter_mutex);
874 		err = -EEXIST;
875 		/* normally audit_add_tree_rule() will free it on failure */
876 		if (tree)
877 			audit_put_tree(tree);
878 		goto error;
879 	}
880 
881 	if (watch) {
882 		/* audit_filter_mutex is dropped and re-taken during this call */
883 		err = audit_add_watch(&entry->rule, &list);
884 		if (err) {
885 			mutex_unlock(&audit_filter_mutex);
886 			/*
887 			 * normally audit_add_tree_rule() will free it
888 			 * on failure
889 			 */
890 			if (tree)
891 				audit_put_tree(tree);
892 			goto error;
893 		}
894 	}
895 	if (tree) {
896 		err = audit_add_tree_rule(&entry->rule);
897 		if (err) {
898 			mutex_unlock(&audit_filter_mutex);
899 			goto error;
900 		}
901 	}
902 
903 	entry->rule.prio = ~0ULL;
904 	if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
905 		if (entry->rule.flags & AUDIT_FILTER_PREPEND)
906 			entry->rule.prio = ++prio_high;
907 		else
908 			entry->rule.prio = --prio_low;
909 	}
910 
911 	if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
912 		list_add(&entry->rule.list,
913 			 &audit_rules_list[entry->rule.listnr]);
914 		list_add_rcu(&entry->list, list);
915 		entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
916 	} else {
917 		list_add_tail(&entry->rule.list,
918 			      &audit_rules_list[entry->rule.listnr]);
919 		list_add_tail_rcu(&entry->list, list);
920 	}
921 #ifdef CONFIG_AUDITSYSCALL
922 	if (!dont_count)
923 		audit_n_rules++;
924 
925 	if (!audit_match_signal(entry))
926 		audit_signals++;
927 #endif
928 	mutex_unlock(&audit_filter_mutex);
929 
930  	return 0;
931 
932 error:
933 	if (watch)
934 		audit_put_watch(watch); /* tmp watch, matches initial get */
935 	return err;
936 }
937 
938 /* Remove an existing rule from filterlist. */
939 static inline int audit_del_rule(struct audit_entry *entry)
940 {
941 	struct audit_entry  *e;
942 	struct audit_watch *watch = entry->rule.watch;
943 	struct audit_tree *tree = entry->rule.tree;
944 	struct list_head *list;
945 	int ret = 0;
946 #ifdef CONFIG_AUDITSYSCALL
947 	int dont_count = 0;
948 
949 	/* If either of these, don't count towards total */
950 	if (entry->rule.listnr == AUDIT_FILTER_USER ||
951 		entry->rule.listnr == AUDIT_FILTER_TYPE)
952 		dont_count = 1;
953 #endif
954 
955 	mutex_lock(&audit_filter_mutex);
956 	e = audit_find_rule(entry, &list);
957 	if (!e) {
958 		mutex_unlock(&audit_filter_mutex);
959 		ret = -ENOENT;
960 		goto out;
961 	}
962 
963 	if (e->rule.watch)
964 		audit_remove_watch_rule(&e->rule);
965 
966 	if (e->rule.tree)
967 		audit_remove_tree_rule(&e->rule);
968 
969 	list_del_rcu(&e->list);
970 	list_del(&e->rule.list);
971 	call_rcu(&e->rcu, audit_free_rule_rcu);
972 
973 #ifdef CONFIG_AUDITSYSCALL
974 	if (!dont_count)
975 		audit_n_rules--;
976 
977 	if (!audit_match_signal(entry))
978 		audit_signals--;
979 #endif
980 	mutex_unlock(&audit_filter_mutex);
981 
982 out:
983 	if (watch)
984 		audit_put_watch(watch); /* match initial get */
985 	if (tree)
986 		audit_put_tree(tree);	/* that's the temporary one */
987 
988 	return ret;
989 }
990 
991 /* List rules using struct audit_rule_data. */
992 static void audit_list_rules(__u32 portid, int seq, struct sk_buff_head *q)
993 {
994 	struct sk_buff *skb;
995 	struct audit_krule *r;
996 	int i;
997 
998 	/* This is a blocking read, so use audit_filter_mutex instead of rcu
999 	 * iterator to sync with list writers. */
1000 	for (i=0; i<AUDIT_NR_FILTERS; i++) {
1001 		list_for_each_entry(r, &audit_rules_list[i], list) {
1002 			struct audit_rule_data *data;
1003 
1004 			data = audit_krule_to_data(r);
1005 			if (unlikely(!data))
1006 				break;
1007 			skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES,
1008 					       0, 1, data,
1009 					       sizeof(*data) + data->buflen);
1010 			if (skb)
1011 				skb_queue_tail(q, skb);
1012 			kfree(data);
1013 		}
1014 	}
1015 	skb = audit_make_reply(portid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1016 	if (skb)
1017 		skb_queue_tail(q, skb);
1018 }
1019 
1020 /* Log rule additions and removals */
1021 static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
1022 {
1023 	struct audit_buffer *ab;
1024 	uid_t loginuid = from_kuid(&init_user_ns, audit_get_loginuid(current));
1025 	unsigned int sessionid = audit_get_sessionid(current);
1026 
1027 	if (!audit_enabled)
1028 		return;
1029 
1030 	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1031 	if (!ab)
1032 		return;
1033 	audit_log_format(ab, "auid=%u ses=%u" ,loginuid, sessionid);
1034 	audit_log_task_context(ab);
1035 	audit_log_format(ab, " op=");
1036 	audit_log_string(ab, action);
1037 	audit_log_key(ab, rule->filterkey);
1038 	audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1039 	audit_log_end(ab);
1040 }
1041 
1042 /**
1043  * audit_rule_change - apply all rules to the specified message type
1044  * @type: audit message type
1045  * @portid: target port id for netlink audit messages
1046  * @seq: netlink audit message sequence (serial) number
1047  * @data: payload data
1048  * @datasz: size of payload data
1049  */
1050 int audit_rule_change(int type, __u32 portid, int seq, void *data,
1051 			size_t datasz)
1052 {
1053 	int err = 0;
1054 	struct audit_entry *entry;
1055 
1056 	switch (type) {
1057 	case AUDIT_ADD_RULE:
1058 		entry = audit_data_to_entry(data, datasz);
1059 		if (IS_ERR(entry))
1060 			return PTR_ERR(entry);
1061 
1062 		err = audit_add_rule(entry);
1063 		audit_log_rule_change("add rule", &entry->rule, !err);
1064 		if (err)
1065 			audit_free_rule(entry);
1066 		break;
1067 	case AUDIT_DEL_RULE:
1068 		entry = audit_data_to_entry(data, datasz);
1069 		if (IS_ERR(entry))
1070 			return PTR_ERR(entry);
1071 
1072 		err = audit_del_rule(entry);
1073 		audit_log_rule_change("remove rule", &entry->rule, !err);
1074 		audit_free_rule(entry);
1075 		break;
1076 	default:
1077 		return -EINVAL;
1078 	}
1079 
1080 	return err;
1081 }
1082 
1083 /**
1084  * audit_list_rules_send - list the audit rules
1085  * @request_skb: skb of request we are replying to (used to target the reply)
1086  * @seq: netlink audit message sequence (serial) number
1087  */
1088 int audit_list_rules_send(struct sk_buff *request_skb, int seq)
1089 {
1090 	u32 portid = NETLINK_CB(request_skb).portid;
1091 	struct net *net = sock_net(NETLINK_CB(request_skb).sk);
1092 	struct task_struct *tsk;
1093 	struct audit_netlink_list *dest;
1094 	int err = 0;
1095 
1096 	/* We can't just spew out the rules here because we might fill
1097 	 * the available socket buffer space and deadlock waiting for
1098 	 * auditctl to read from it... which isn't ever going to
1099 	 * happen if we're actually running in the context of auditctl
1100 	 * trying to _send_ the stuff */
1101 
1102 	dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1103 	if (!dest)
1104 		return -ENOMEM;
1105 	dest->net = get_net(net);
1106 	dest->portid = portid;
1107 	skb_queue_head_init(&dest->q);
1108 
1109 	mutex_lock(&audit_filter_mutex);
1110 	audit_list_rules(portid, seq, &dest->q);
1111 	mutex_unlock(&audit_filter_mutex);
1112 
1113 	tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1114 	if (IS_ERR(tsk)) {
1115 		skb_queue_purge(&dest->q);
1116 		kfree(dest);
1117 		err = PTR_ERR(tsk);
1118 	}
1119 
1120 	return err;
1121 }
1122 
1123 int audit_comparator(u32 left, u32 op, u32 right)
1124 {
1125 	switch (op) {
1126 	case Audit_equal:
1127 		return (left == right);
1128 	case Audit_not_equal:
1129 		return (left != right);
1130 	case Audit_lt:
1131 		return (left < right);
1132 	case Audit_le:
1133 		return (left <= right);
1134 	case Audit_gt:
1135 		return (left > right);
1136 	case Audit_ge:
1137 		return (left >= right);
1138 	case Audit_bitmask:
1139 		return (left & right);
1140 	case Audit_bittest:
1141 		return ((left & right) == right);
1142 	default:
1143 		BUG();
1144 		return 0;
1145 	}
1146 }
1147 
1148 int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1149 {
1150 	switch (op) {
1151 	case Audit_equal:
1152 		return uid_eq(left, right);
1153 	case Audit_not_equal:
1154 		return !uid_eq(left, right);
1155 	case Audit_lt:
1156 		return uid_lt(left, right);
1157 	case Audit_le:
1158 		return uid_lte(left, right);
1159 	case Audit_gt:
1160 		return uid_gt(left, right);
1161 	case Audit_ge:
1162 		return uid_gte(left, right);
1163 	case Audit_bitmask:
1164 	case Audit_bittest:
1165 	default:
1166 		BUG();
1167 		return 0;
1168 	}
1169 }
1170 
1171 int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1172 {
1173 	switch (op) {
1174 	case Audit_equal:
1175 		return gid_eq(left, right);
1176 	case Audit_not_equal:
1177 		return !gid_eq(left, right);
1178 	case Audit_lt:
1179 		return gid_lt(left, right);
1180 	case Audit_le:
1181 		return gid_lte(left, right);
1182 	case Audit_gt:
1183 		return gid_gt(left, right);
1184 	case Audit_ge:
1185 		return gid_gte(left, right);
1186 	case Audit_bitmask:
1187 	case Audit_bittest:
1188 	default:
1189 		BUG();
1190 		return 0;
1191 	}
1192 }
1193 
1194 /**
1195  * parent_len - find the length of the parent portion of a pathname
1196  * @path: pathname of which to determine length
1197  */
1198 int parent_len(const char *path)
1199 {
1200 	int plen;
1201 	const char *p;
1202 
1203 	plen = strlen(path);
1204 
1205 	if (plen == 0)
1206 		return plen;
1207 
1208 	/* disregard trailing slashes */
1209 	p = path + plen - 1;
1210 	while ((*p == '/') && (p > path))
1211 		p--;
1212 
1213 	/* walk backward until we find the next slash or hit beginning */
1214 	while ((*p != '/') && (p > path))
1215 		p--;
1216 
1217 	/* did we find a slash? Then increment to include it in path */
1218 	if (*p == '/')
1219 		p++;
1220 
1221 	return p - path;
1222 }
1223 
1224 /**
1225  * audit_compare_dname_path - compare given dentry name with last component in
1226  * 			      given path. Return of 0 indicates a match.
1227  * @dname:	dentry name that we're comparing
1228  * @path:	full pathname that we're comparing
1229  * @parentlen:	length of the parent if known. Passing in AUDIT_NAME_FULL
1230  * 		here indicates that we must compute this value.
1231  */
1232 int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
1233 {
1234 	int dlen, pathlen;
1235 	const char *p;
1236 
1237 	dlen = strlen(dname);
1238 	pathlen = strlen(path);
1239 	if (pathlen < dlen)
1240 		return 1;
1241 
1242 	parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1243 	if (pathlen - parentlen != dlen)
1244 		return 1;
1245 
1246 	p = path + parentlen;
1247 
1248 	return strncmp(p, dname, dlen);
1249 }
1250 
1251 static int audit_filter_user_rules(struct audit_krule *rule, int type,
1252 				   enum audit_state *state)
1253 {
1254 	int i;
1255 
1256 	for (i = 0; i < rule->field_count; i++) {
1257 		struct audit_field *f = &rule->fields[i];
1258 		pid_t pid;
1259 		int result = 0;
1260 		u32 sid;
1261 
1262 		switch (f->type) {
1263 		case AUDIT_PID:
1264 			pid = task_pid_nr(current);
1265 			result = audit_comparator(pid, f->op, f->val);
1266 			break;
1267 		case AUDIT_UID:
1268 			result = audit_uid_comparator(current_uid(), f->op, f->uid);
1269 			break;
1270 		case AUDIT_GID:
1271 			result = audit_gid_comparator(current_gid(), f->op, f->gid);
1272 			break;
1273 		case AUDIT_LOGINUID:
1274 			result = audit_uid_comparator(audit_get_loginuid(current),
1275 						  f->op, f->uid);
1276 			break;
1277 		case AUDIT_LOGINUID_SET:
1278 			result = audit_comparator(audit_loginuid_set(current),
1279 						  f->op, f->val);
1280 			break;
1281 		case AUDIT_MSGTYPE:
1282 			result = audit_comparator(type, f->op, f->val);
1283 			break;
1284 		case AUDIT_SUBJ_USER:
1285 		case AUDIT_SUBJ_ROLE:
1286 		case AUDIT_SUBJ_TYPE:
1287 		case AUDIT_SUBJ_SEN:
1288 		case AUDIT_SUBJ_CLR:
1289 			if (f->lsm_rule) {
1290 				security_task_getsecid(current, &sid);
1291 				result = security_audit_rule_match(sid,
1292 								   f->type,
1293 								   f->op,
1294 								   f->lsm_rule,
1295 								   NULL);
1296 			}
1297 			break;
1298 		}
1299 
1300 		if (!result)
1301 			return 0;
1302 	}
1303 	switch (rule->action) {
1304 	case AUDIT_NEVER:    *state = AUDIT_DISABLED;	    break;
1305 	case AUDIT_ALWAYS:   *state = AUDIT_RECORD_CONTEXT; break;
1306 	}
1307 	return 1;
1308 }
1309 
1310 int audit_filter_user(int type)
1311 {
1312 	enum audit_state state = AUDIT_DISABLED;
1313 	struct audit_entry *e;
1314 	int rc, ret;
1315 
1316 	ret = 1; /* Audit by default */
1317 
1318 	rcu_read_lock();
1319 	list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1320 		rc = audit_filter_user_rules(&e->rule, type, &state);
1321 		if (rc) {
1322 			if (rc > 0 && state == AUDIT_DISABLED)
1323 				ret = 0;
1324 			break;
1325 		}
1326 	}
1327 	rcu_read_unlock();
1328 
1329 	return ret;
1330 }
1331 
1332 int audit_filter_type(int type)
1333 {
1334 	struct audit_entry *e;
1335 	int result = 0;
1336 
1337 	rcu_read_lock();
1338 	if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1339 		goto unlock_and_return;
1340 
1341 	list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1342 				list) {
1343 		int i;
1344 		for (i = 0; i < e->rule.field_count; i++) {
1345 			struct audit_field *f = &e->rule.fields[i];
1346 			if (f->type == AUDIT_MSGTYPE) {
1347 				result = audit_comparator(type, f->op, f->val);
1348 				if (!result)
1349 					break;
1350 			}
1351 		}
1352 		if (result)
1353 			goto unlock_and_return;
1354 	}
1355 unlock_and_return:
1356 	rcu_read_unlock();
1357 	return result;
1358 }
1359 
1360 static int update_lsm_rule(struct audit_krule *r)
1361 {
1362 	struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1363 	struct audit_entry *nentry;
1364 	int err = 0;
1365 
1366 	if (!security_audit_rule_known(r))
1367 		return 0;
1368 
1369 	nentry = audit_dupe_rule(r);
1370 	if (IS_ERR(nentry)) {
1371 		/* save the first error encountered for the
1372 		 * return value */
1373 		err = PTR_ERR(nentry);
1374 		audit_panic("error updating LSM filters");
1375 		if (r->watch)
1376 			list_del(&r->rlist);
1377 		list_del_rcu(&entry->list);
1378 		list_del(&r->list);
1379 	} else {
1380 		if (r->watch || r->tree)
1381 			list_replace_init(&r->rlist, &nentry->rule.rlist);
1382 		list_replace_rcu(&entry->list, &nentry->list);
1383 		list_replace(&r->list, &nentry->rule.list);
1384 	}
1385 	call_rcu(&entry->rcu, audit_free_rule_rcu);
1386 
1387 	return err;
1388 }
1389 
1390 /* This function will re-initialize the lsm_rule field of all applicable rules.
1391  * It will traverse the filter lists serarching for rules that contain LSM
1392  * specific filter fields.  When such a rule is found, it is copied, the
1393  * LSM field is re-initialized, and the old rule is replaced with the
1394  * updated rule. */
1395 int audit_update_lsm_rules(void)
1396 {
1397 	struct audit_krule *r, *n;
1398 	int i, err = 0;
1399 
1400 	/* audit_filter_mutex synchronizes the writers */
1401 	mutex_lock(&audit_filter_mutex);
1402 
1403 	for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1404 		list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1405 			int res = update_lsm_rule(r);
1406 			if (!err)
1407 				err = res;
1408 		}
1409 	}
1410 	mutex_unlock(&audit_filter_mutex);
1411 
1412 	return err;
1413 }
1414