xref: /linux/kernel/auditfilter.c (revision 791d3ef2e11100449837dc0b6fe884e60ca3a484)
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 	LIST_HEAD_INIT(audit_filter_list[6]),
60 #if AUDIT_NR_FILTERS != 7
61 #error Fix audit_filter_list initialiser
62 #endif
63 };
64 static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
65 	LIST_HEAD_INIT(audit_rules_list[0]),
66 	LIST_HEAD_INIT(audit_rules_list[1]),
67 	LIST_HEAD_INIT(audit_rules_list[2]),
68 	LIST_HEAD_INIT(audit_rules_list[3]),
69 	LIST_HEAD_INIT(audit_rules_list[4]),
70 	LIST_HEAD_INIT(audit_rules_list[5]),
71 	LIST_HEAD_INIT(audit_rules_list[6]),
72 };
73 
74 DEFINE_MUTEX(audit_filter_mutex);
75 
76 static void audit_free_lsm_field(struct audit_field *f)
77 {
78 	switch (f->type) {
79 	case AUDIT_SUBJ_USER:
80 	case AUDIT_SUBJ_ROLE:
81 	case AUDIT_SUBJ_TYPE:
82 	case AUDIT_SUBJ_SEN:
83 	case AUDIT_SUBJ_CLR:
84 	case AUDIT_OBJ_USER:
85 	case AUDIT_OBJ_ROLE:
86 	case AUDIT_OBJ_TYPE:
87 	case AUDIT_OBJ_LEV_LOW:
88 	case AUDIT_OBJ_LEV_HIGH:
89 		kfree(f->lsm_str);
90 		security_audit_rule_free(f->lsm_rule);
91 	}
92 }
93 
94 static inline void audit_free_rule(struct audit_entry *e)
95 {
96 	int i;
97 	struct audit_krule *erule = &e->rule;
98 
99 	/* some rules don't have associated watches */
100 	if (erule->watch)
101 		audit_put_watch(erule->watch);
102 	if (erule->fields)
103 		for (i = 0; i < erule->field_count; i++)
104 			audit_free_lsm_field(&erule->fields[i]);
105 	kfree(erule->fields);
106 	kfree(erule->filterkey);
107 	kfree(e);
108 }
109 
110 void audit_free_rule_rcu(struct rcu_head *head)
111 {
112 	struct audit_entry *e = container_of(head, struct audit_entry, rcu);
113 	audit_free_rule(e);
114 }
115 
116 /* Initialize an audit filterlist entry. */
117 static inline struct audit_entry *audit_init_entry(u32 field_count)
118 {
119 	struct audit_entry *entry;
120 	struct audit_field *fields;
121 
122 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
123 	if (unlikely(!entry))
124 		return NULL;
125 
126 	fields = kcalloc(field_count, sizeof(*fields), GFP_KERNEL);
127 	if (unlikely(!fields)) {
128 		kfree(entry);
129 		return NULL;
130 	}
131 	entry->rule.fields = fields;
132 
133 	return entry;
134 }
135 
136 /* Unpack a filter field's string representation from user-space
137  * buffer. */
138 char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
139 {
140 	char *str;
141 
142 	if (!*bufp || (len == 0) || (len > *remain))
143 		return ERR_PTR(-EINVAL);
144 
145 	/* Of the currently implemented string fields, PATH_MAX
146 	 * defines the longest valid length.
147 	 */
148 	if (len > PATH_MAX)
149 		return ERR_PTR(-ENAMETOOLONG);
150 
151 	str = kmalloc(len + 1, GFP_KERNEL);
152 	if (unlikely(!str))
153 		return ERR_PTR(-ENOMEM);
154 
155 	memcpy(str, *bufp, len);
156 	str[len] = 0;
157 	*bufp += len;
158 	*remain -= len;
159 
160 	return str;
161 }
162 
163 /* Translate an inode field to kernel representation. */
164 static inline int audit_to_inode(struct audit_krule *krule,
165 				 struct audit_field *f)
166 {
167 	if (krule->listnr != AUDIT_FILTER_EXIT ||
168 	    krule->inode_f || krule->watch || krule->tree ||
169 	    (f->op != Audit_equal && f->op != Audit_not_equal))
170 		return -EINVAL;
171 
172 	krule->inode_f = f;
173 	return 0;
174 }
175 
176 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
177 
178 int __init audit_register_class(int class, unsigned *list)
179 {
180 	__u32 *p = kcalloc(AUDIT_BITMASK_SIZE, sizeof(__u32), GFP_KERNEL);
181 	if (!p)
182 		return -ENOMEM;
183 	while (*list != ~0U) {
184 		unsigned n = *list++;
185 		if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
186 			kfree(p);
187 			return -EINVAL;
188 		}
189 		p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
190 	}
191 	if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
192 		kfree(p);
193 		return -EINVAL;
194 	}
195 	classes[class] = p;
196 	return 0;
197 }
198 
199 int audit_match_class(int class, unsigned syscall)
200 {
201 	if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
202 		return 0;
203 	if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
204 		return 0;
205 	return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
206 }
207 
208 #ifdef CONFIG_AUDITSYSCALL
209 static inline int audit_match_class_bits(int class, u32 *mask)
210 {
211 	int i;
212 
213 	if (classes[class]) {
214 		for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
215 			if (mask[i] & classes[class][i])
216 				return 0;
217 	}
218 	return 1;
219 }
220 
221 static int audit_match_signal(struct audit_entry *entry)
222 {
223 	struct audit_field *arch = entry->rule.arch_f;
224 
225 	if (!arch) {
226 		/* When arch is unspecified, we must check both masks on biarch
227 		 * as syscall number alone is ambiguous. */
228 		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
229 					       entry->rule.mask) &&
230 			audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
231 					       entry->rule.mask));
232 	}
233 
234 	switch(audit_classify_arch(arch->val)) {
235 	case 0: /* native */
236 		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
237 					       entry->rule.mask));
238 	case 1: /* 32bit on biarch */
239 		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
240 					       entry->rule.mask));
241 	default:
242 		return 1;
243 	}
244 }
245 #endif
246 
247 /* Common user-space to kernel rule translation. */
248 static inline struct audit_entry *audit_to_entry_common(struct audit_rule_data *rule)
249 {
250 	unsigned listnr;
251 	struct audit_entry *entry;
252 	int i, err;
253 
254 	err = -EINVAL;
255 	listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
256 	switch(listnr) {
257 	default:
258 		goto exit_err;
259 #ifdef CONFIG_AUDITSYSCALL
260 	case AUDIT_FILTER_ENTRY:
261 		pr_err("AUDIT_FILTER_ENTRY is deprecated\n");
262 		goto exit_err;
263 	case AUDIT_FILTER_EXIT:
264 	case AUDIT_FILTER_TASK:
265 #endif
266 	case AUDIT_FILTER_USER:
267 	case AUDIT_FILTER_TYPE:
268 	case AUDIT_FILTER_FS:
269 		;
270 	}
271 	if (unlikely(rule->action == AUDIT_POSSIBLE)) {
272 		pr_err("AUDIT_POSSIBLE is deprecated\n");
273 		goto exit_err;
274 	}
275 	if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
276 		goto exit_err;
277 	if (rule->field_count > AUDIT_MAX_FIELDS)
278 		goto exit_err;
279 
280 	err = -ENOMEM;
281 	entry = audit_init_entry(rule->field_count);
282 	if (!entry)
283 		goto exit_err;
284 
285 	entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
286 	entry->rule.listnr = listnr;
287 	entry->rule.action = rule->action;
288 	entry->rule.field_count = rule->field_count;
289 
290 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
291 		entry->rule.mask[i] = rule->mask[i];
292 
293 	for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
294 		int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
295 		__u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
296 		__u32 *class;
297 
298 		if (!(*p & AUDIT_BIT(bit)))
299 			continue;
300 		*p &= ~AUDIT_BIT(bit);
301 		class = classes[i];
302 		if (class) {
303 			int j;
304 			for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
305 				entry->rule.mask[j] |= class[j];
306 		}
307 	}
308 
309 	return entry;
310 
311 exit_err:
312 	return ERR_PTR(err);
313 }
314 
315 static u32 audit_ops[] =
316 {
317 	[Audit_equal] = AUDIT_EQUAL,
318 	[Audit_not_equal] = AUDIT_NOT_EQUAL,
319 	[Audit_bitmask] = AUDIT_BIT_MASK,
320 	[Audit_bittest] = AUDIT_BIT_TEST,
321 	[Audit_lt] = AUDIT_LESS_THAN,
322 	[Audit_gt] = AUDIT_GREATER_THAN,
323 	[Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
324 	[Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
325 };
326 
327 static u32 audit_to_op(u32 op)
328 {
329 	u32 n;
330 	for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
331 		;
332 	return n;
333 }
334 
335 /* check if an audit field is valid */
336 static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
337 {
338 	switch(f->type) {
339 	case AUDIT_MSGTYPE:
340 		if (entry->rule.listnr != AUDIT_FILTER_TYPE &&
341 		    entry->rule.listnr != AUDIT_FILTER_USER)
342 			return -EINVAL;
343 		break;
344 	case AUDIT_FSTYPE:
345 		if (entry->rule.listnr != AUDIT_FILTER_FS)
346 			return -EINVAL;
347 		break;
348 	}
349 
350 	switch(entry->rule.listnr) {
351 	case AUDIT_FILTER_FS:
352 		switch(f->type) {
353 		case AUDIT_FSTYPE:
354 		case AUDIT_FILTERKEY:
355 			break;
356 		default:
357 			return -EINVAL;
358 		}
359 	}
360 
361 	switch(f->type) {
362 	default:
363 		return -EINVAL;
364 	case AUDIT_UID:
365 	case AUDIT_EUID:
366 	case AUDIT_SUID:
367 	case AUDIT_FSUID:
368 	case AUDIT_LOGINUID:
369 	case AUDIT_OBJ_UID:
370 	case AUDIT_GID:
371 	case AUDIT_EGID:
372 	case AUDIT_SGID:
373 	case AUDIT_FSGID:
374 	case AUDIT_OBJ_GID:
375 	case AUDIT_PID:
376 	case AUDIT_PERS:
377 	case AUDIT_MSGTYPE:
378 	case AUDIT_PPID:
379 	case AUDIT_DEVMAJOR:
380 	case AUDIT_DEVMINOR:
381 	case AUDIT_EXIT:
382 	case AUDIT_SUCCESS:
383 	case AUDIT_INODE:
384 	case AUDIT_SESSIONID:
385 		/* bit ops are only useful on syscall args */
386 		if (f->op == Audit_bitmask || f->op == Audit_bittest)
387 			return -EINVAL;
388 		break;
389 	case AUDIT_ARG0:
390 	case AUDIT_ARG1:
391 	case AUDIT_ARG2:
392 	case AUDIT_ARG3:
393 	case AUDIT_SUBJ_USER:
394 	case AUDIT_SUBJ_ROLE:
395 	case AUDIT_SUBJ_TYPE:
396 	case AUDIT_SUBJ_SEN:
397 	case AUDIT_SUBJ_CLR:
398 	case AUDIT_OBJ_USER:
399 	case AUDIT_OBJ_ROLE:
400 	case AUDIT_OBJ_TYPE:
401 	case AUDIT_OBJ_LEV_LOW:
402 	case AUDIT_OBJ_LEV_HIGH:
403 	case AUDIT_WATCH:
404 	case AUDIT_DIR:
405 	case AUDIT_FILTERKEY:
406 		break;
407 	case AUDIT_LOGINUID_SET:
408 		if ((f->val != 0) && (f->val != 1))
409 			return -EINVAL;
410 	/* FALL THROUGH */
411 	case AUDIT_ARCH:
412 	case AUDIT_FSTYPE:
413 		if (f->op != Audit_not_equal && f->op != Audit_equal)
414 			return -EINVAL;
415 		break;
416 	case AUDIT_PERM:
417 		if (f->val & ~15)
418 			return -EINVAL;
419 		break;
420 	case AUDIT_FILETYPE:
421 		if (f->val & ~S_IFMT)
422 			return -EINVAL;
423 		break;
424 	case AUDIT_FIELD_COMPARE:
425 		if (f->val > AUDIT_MAX_FIELD_COMPARE)
426 			return -EINVAL;
427 		break;
428 	case AUDIT_EXE:
429 		if (f->op != Audit_not_equal && f->op != Audit_equal)
430 			return -EINVAL;
431 		if (entry->rule.listnr != AUDIT_FILTER_EXIT)
432 			return -EINVAL;
433 		break;
434 	}
435 	return 0;
436 }
437 
438 /* Translate struct audit_rule_data to kernel's rule representation. */
439 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
440 					       size_t datasz)
441 {
442 	int err = 0;
443 	struct audit_entry *entry;
444 	void *bufp;
445 	size_t remain = datasz - sizeof(struct audit_rule_data);
446 	int i;
447 	char *str;
448 	struct audit_fsnotify_mark *audit_mark;
449 
450 	entry = audit_to_entry_common(data);
451 	if (IS_ERR(entry))
452 		goto exit_nofree;
453 
454 	bufp = data->buf;
455 	for (i = 0; i < data->field_count; i++) {
456 		struct audit_field *f = &entry->rule.fields[i];
457 
458 		err = -EINVAL;
459 
460 		f->op = audit_to_op(data->fieldflags[i]);
461 		if (f->op == Audit_bad)
462 			goto exit_free;
463 
464 		f->type = data->fields[i];
465 		f->val = data->values[i];
466 
467 		/* Support legacy tests for a valid loginuid */
468 		if ((f->type == AUDIT_LOGINUID) && (f->val == AUDIT_UID_UNSET)) {
469 			f->type = AUDIT_LOGINUID_SET;
470 			f->val = 0;
471 			entry->rule.pflags |= AUDIT_LOGINUID_LEGACY;
472 		}
473 
474 		err = audit_field_valid(entry, f);
475 		if (err)
476 			goto exit_free;
477 
478 		err = -EINVAL;
479 		switch (f->type) {
480 		case AUDIT_LOGINUID:
481 		case AUDIT_UID:
482 		case AUDIT_EUID:
483 		case AUDIT_SUID:
484 		case AUDIT_FSUID:
485 		case AUDIT_OBJ_UID:
486 			f->uid = make_kuid(current_user_ns(), f->val);
487 			if (!uid_valid(f->uid))
488 				goto exit_free;
489 			break;
490 		case AUDIT_GID:
491 		case AUDIT_EGID:
492 		case AUDIT_SGID:
493 		case AUDIT_FSGID:
494 		case AUDIT_OBJ_GID:
495 			f->gid = make_kgid(current_user_ns(), f->val);
496 			if (!gid_valid(f->gid))
497 				goto exit_free;
498 			break;
499 		case AUDIT_ARCH:
500 			entry->rule.arch_f = f;
501 			break;
502 		case AUDIT_SUBJ_USER:
503 		case AUDIT_SUBJ_ROLE:
504 		case AUDIT_SUBJ_TYPE:
505 		case AUDIT_SUBJ_SEN:
506 		case AUDIT_SUBJ_CLR:
507 		case AUDIT_OBJ_USER:
508 		case AUDIT_OBJ_ROLE:
509 		case AUDIT_OBJ_TYPE:
510 		case AUDIT_OBJ_LEV_LOW:
511 		case AUDIT_OBJ_LEV_HIGH:
512 			str = audit_unpack_string(&bufp, &remain, f->val);
513 			if (IS_ERR(str))
514 				goto exit_free;
515 			entry->rule.buflen += f->val;
516 
517 			err = security_audit_rule_init(f->type, f->op, str,
518 						       (void **)&f->lsm_rule);
519 			/* Keep currently invalid fields around in case they
520 			 * become valid after a policy reload. */
521 			if (err == -EINVAL) {
522 				pr_warn("audit rule for LSM \'%s\' is invalid\n",
523 					str);
524 				err = 0;
525 			}
526 			if (err) {
527 				kfree(str);
528 				goto exit_free;
529 			} else
530 				f->lsm_str = str;
531 			break;
532 		case AUDIT_WATCH:
533 			str = audit_unpack_string(&bufp, &remain, f->val);
534 			if (IS_ERR(str))
535 				goto exit_free;
536 			entry->rule.buflen += f->val;
537 
538 			err = audit_to_watch(&entry->rule, str, f->val, f->op);
539 			if (err) {
540 				kfree(str);
541 				goto exit_free;
542 			}
543 			break;
544 		case AUDIT_DIR:
545 			str = audit_unpack_string(&bufp, &remain, f->val);
546 			if (IS_ERR(str))
547 				goto exit_free;
548 			entry->rule.buflen += f->val;
549 
550 			err = audit_make_tree(&entry->rule, str, f->op);
551 			kfree(str);
552 			if (err)
553 				goto exit_free;
554 			break;
555 		case AUDIT_INODE:
556 			err = audit_to_inode(&entry->rule, f);
557 			if (err)
558 				goto exit_free;
559 			break;
560 		case AUDIT_FILTERKEY:
561 			if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
562 				goto exit_free;
563 			str = audit_unpack_string(&bufp, &remain, f->val);
564 			if (IS_ERR(str))
565 				goto exit_free;
566 			entry->rule.buflen += f->val;
567 			entry->rule.filterkey = str;
568 			break;
569 		case AUDIT_EXE:
570 			if (entry->rule.exe || f->val > PATH_MAX)
571 				goto exit_free;
572 			str = audit_unpack_string(&bufp, &remain, f->val);
573 			if (IS_ERR(str)) {
574 				err = PTR_ERR(str);
575 				goto exit_free;
576 			}
577 			entry->rule.buflen += f->val;
578 
579 			audit_mark = audit_alloc_mark(&entry->rule, str, f->val);
580 			if (IS_ERR(audit_mark)) {
581 				kfree(str);
582 				err = PTR_ERR(audit_mark);
583 				goto exit_free;
584 			}
585 			entry->rule.exe = audit_mark;
586 			break;
587 		}
588 	}
589 
590 	if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
591 		entry->rule.inode_f = NULL;
592 
593 exit_nofree:
594 	return entry;
595 
596 exit_free:
597 	if (entry->rule.tree)
598 		audit_put_tree(entry->rule.tree); /* that's the temporary one */
599 	if (entry->rule.exe)
600 		audit_remove_mark(entry->rule.exe); /* that's the template one */
601 	audit_free_rule(entry);
602 	return ERR_PTR(err);
603 }
604 
605 /* Pack a filter field's string representation into data block. */
606 static inline size_t audit_pack_string(void **bufp, const char *str)
607 {
608 	size_t len = strlen(str);
609 
610 	memcpy(*bufp, str, len);
611 	*bufp += len;
612 
613 	return len;
614 }
615 
616 /* Translate kernel rule representation to struct audit_rule_data. */
617 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
618 {
619 	struct audit_rule_data *data;
620 	void *bufp;
621 	int i;
622 
623 	data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
624 	if (unlikely(!data))
625 		return NULL;
626 	memset(data, 0, sizeof(*data));
627 
628 	data->flags = krule->flags | krule->listnr;
629 	data->action = krule->action;
630 	data->field_count = krule->field_count;
631 	bufp = data->buf;
632 	for (i = 0; i < data->field_count; i++) {
633 		struct audit_field *f = &krule->fields[i];
634 
635 		data->fields[i] = f->type;
636 		data->fieldflags[i] = audit_ops[f->op];
637 		switch(f->type) {
638 		case AUDIT_SUBJ_USER:
639 		case AUDIT_SUBJ_ROLE:
640 		case AUDIT_SUBJ_TYPE:
641 		case AUDIT_SUBJ_SEN:
642 		case AUDIT_SUBJ_CLR:
643 		case AUDIT_OBJ_USER:
644 		case AUDIT_OBJ_ROLE:
645 		case AUDIT_OBJ_TYPE:
646 		case AUDIT_OBJ_LEV_LOW:
647 		case AUDIT_OBJ_LEV_HIGH:
648 			data->buflen += data->values[i] =
649 				audit_pack_string(&bufp, f->lsm_str);
650 			break;
651 		case AUDIT_WATCH:
652 			data->buflen += data->values[i] =
653 				audit_pack_string(&bufp,
654 						  audit_watch_path(krule->watch));
655 			break;
656 		case AUDIT_DIR:
657 			data->buflen += data->values[i] =
658 				audit_pack_string(&bufp,
659 						  audit_tree_path(krule->tree));
660 			break;
661 		case AUDIT_FILTERKEY:
662 			data->buflen += data->values[i] =
663 				audit_pack_string(&bufp, krule->filterkey);
664 			break;
665 		case AUDIT_EXE:
666 			data->buflen += data->values[i] =
667 				audit_pack_string(&bufp, audit_mark_path(krule->exe));
668 			break;
669 		case AUDIT_LOGINUID_SET:
670 			if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) {
671 				data->fields[i] = AUDIT_LOGINUID;
672 				data->values[i] = AUDIT_UID_UNSET;
673 				break;
674 			}
675 			/* fallthrough if set */
676 		default:
677 			data->values[i] = f->val;
678 		}
679 	}
680 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
681 
682 	return data;
683 }
684 
685 /* Compare two rules in kernel format.  Considered success if rules
686  * don't match. */
687 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
688 {
689 	int i;
690 
691 	if (a->flags != b->flags ||
692 	    a->pflags != b->pflags ||
693 	    a->listnr != b->listnr ||
694 	    a->action != b->action ||
695 	    a->field_count != b->field_count)
696 		return 1;
697 
698 	for (i = 0; i < a->field_count; i++) {
699 		if (a->fields[i].type != b->fields[i].type ||
700 		    a->fields[i].op != b->fields[i].op)
701 			return 1;
702 
703 		switch(a->fields[i].type) {
704 		case AUDIT_SUBJ_USER:
705 		case AUDIT_SUBJ_ROLE:
706 		case AUDIT_SUBJ_TYPE:
707 		case AUDIT_SUBJ_SEN:
708 		case AUDIT_SUBJ_CLR:
709 		case AUDIT_OBJ_USER:
710 		case AUDIT_OBJ_ROLE:
711 		case AUDIT_OBJ_TYPE:
712 		case AUDIT_OBJ_LEV_LOW:
713 		case AUDIT_OBJ_LEV_HIGH:
714 			if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
715 				return 1;
716 			break;
717 		case AUDIT_WATCH:
718 			if (strcmp(audit_watch_path(a->watch),
719 				   audit_watch_path(b->watch)))
720 				return 1;
721 			break;
722 		case AUDIT_DIR:
723 			if (strcmp(audit_tree_path(a->tree),
724 				   audit_tree_path(b->tree)))
725 				return 1;
726 			break;
727 		case AUDIT_FILTERKEY:
728 			/* both filterkeys exist based on above type compare */
729 			if (strcmp(a->filterkey, b->filterkey))
730 				return 1;
731 			break;
732 		case AUDIT_EXE:
733 			/* both paths exist based on above type compare */
734 			if (strcmp(audit_mark_path(a->exe),
735 				   audit_mark_path(b->exe)))
736 				return 1;
737 			break;
738 		case AUDIT_UID:
739 		case AUDIT_EUID:
740 		case AUDIT_SUID:
741 		case AUDIT_FSUID:
742 		case AUDIT_LOGINUID:
743 		case AUDIT_OBJ_UID:
744 			if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
745 				return 1;
746 			break;
747 		case AUDIT_GID:
748 		case AUDIT_EGID:
749 		case AUDIT_SGID:
750 		case AUDIT_FSGID:
751 		case AUDIT_OBJ_GID:
752 			if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
753 				return 1;
754 			break;
755 		default:
756 			if (a->fields[i].val != b->fields[i].val)
757 				return 1;
758 		}
759 	}
760 
761 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
762 		if (a->mask[i] != b->mask[i])
763 			return 1;
764 
765 	return 0;
766 }
767 
768 /* Duplicate LSM field information.  The lsm_rule is opaque, so must be
769  * re-initialized. */
770 static inline int audit_dupe_lsm_field(struct audit_field *df,
771 					   struct audit_field *sf)
772 {
773 	int ret = 0;
774 	char *lsm_str;
775 
776 	/* our own copy of lsm_str */
777 	lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
778 	if (unlikely(!lsm_str))
779 		return -ENOMEM;
780 	df->lsm_str = lsm_str;
781 
782 	/* our own (refreshed) copy of lsm_rule */
783 	ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
784 				       (void **)&df->lsm_rule);
785 	/* Keep currently invalid fields around in case they
786 	 * become valid after a policy reload. */
787 	if (ret == -EINVAL) {
788 		pr_warn("audit rule for LSM \'%s\' is invalid\n",
789 			df->lsm_str);
790 		ret = 0;
791 	}
792 
793 	return ret;
794 }
795 
796 /* Duplicate an audit rule.  This will be a deep copy with the exception
797  * of the watch - that pointer is carried over.  The LSM specific fields
798  * will be updated in the copy.  The point is to be able to replace the old
799  * rule with the new rule in the filterlist, then free the old rule.
800  * The rlist element is undefined; list manipulations are handled apart from
801  * the initial copy. */
802 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
803 {
804 	u32 fcount = old->field_count;
805 	struct audit_entry *entry;
806 	struct audit_krule *new;
807 	char *fk;
808 	int i, err = 0;
809 
810 	entry = audit_init_entry(fcount);
811 	if (unlikely(!entry))
812 		return ERR_PTR(-ENOMEM);
813 
814 	new = &entry->rule;
815 	new->flags = old->flags;
816 	new->pflags = old->pflags;
817 	new->listnr = old->listnr;
818 	new->action = old->action;
819 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
820 		new->mask[i] = old->mask[i];
821 	new->prio = old->prio;
822 	new->buflen = old->buflen;
823 	new->inode_f = old->inode_f;
824 	new->field_count = old->field_count;
825 
826 	/*
827 	 * note that we are OK with not refcounting here; audit_match_tree()
828 	 * never dereferences tree and we can't get false positives there
829 	 * since we'd have to have rule gone from the list *and* removed
830 	 * before the chunks found by lookup had been allocated, i.e. before
831 	 * the beginning of list scan.
832 	 */
833 	new->tree = old->tree;
834 	memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
835 
836 	/* deep copy this information, updating the lsm_rule fields, because
837 	 * the originals will all be freed when the old rule is freed. */
838 	for (i = 0; i < fcount; i++) {
839 		switch (new->fields[i].type) {
840 		case AUDIT_SUBJ_USER:
841 		case AUDIT_SUBJ_ROLE:
842 		case AUDIT_SUBJ_TYPE:
843 		case AUDIT_SUBJ_SEN:
844 		case AUDIT_SUBJ_CLR:
845 		case AUDIT_OBJ_USER:
846 		case AUDIT_OBJ_ROLE:
847 		case AUDIT_OBJ_TYPE:
848 		case AUDIT_OBJ_LEV_LOW:
849 		case AUDIT_OBJ_LEV_HIGH:
850 			err = audit_dupe_lsm_field(&new->fields[i],
851 						       &old->fields[i]);
852 			break;
853 		case AUDIT_FILTERKEY:
854 			fk = kstrdup(old->filterkey, GFP_KERNEL);
855 			if (unlikely(!fk))
856 				err = -ENOMEM;
857 			else
858 				new->filterkey = fk;
859 			break;
860 		case AUDIT_EXE:
861 			err = audit_dupe_exe(new, old);
862 			break;
863 		}
864 		if (err) {
865 			if (new->exe)
866 				audit_remove_mark(new->exe);
867 			audit_free_rule(entry);
868 			return ERR_PTR(err);
869 		}
870 	}
871 
872 	if (old->watch) {
873 		audit_get_watch(old->watch);
874 		new->watch = old->watch;
875 	}
876 
877 	return entry;
878 }
879 
880 /* Find an existing audit rule.
881  * Caller must hold audit_filter_mutex to prevent stale rule data. */
882 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
883 					   struct list_head **p)
884 {
885 	struct audit_entry *e, *found = NULL;
886 	struct list_head *list;
887 	int h;
888 
889 	if (entry->rule.inode_f) {
890 		h = audit_hash_ino(entry->rule.inode_f->val);
891 		*p = list = &audit_inode_hash[h];
892 	} else if (entry->rule.watch) {
893 		/* we don't know the inode number, so must walk entire hash */
894 		for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
895 			list = &audit_inode_hash[h];
896 			list_for_each_entry(e, list, list)
897 				if (!audit_compare_rule(&entry->rule, &e->rule)) {
898 					found = e;
899 					goto out;
900 				}
901 		}
902 		goto out;
903 	} else {
904 		*p = list = &audit_filter_list[entry->rule.listnr];
905 	}
906 
907 	list_for_each_entry(e, list, list)
908 		if (!audit_compare_rule(&entry->rule, &e->rule)) {
909 			found = e;
910 			goto out;
911 		}
912 
913 out:
914 	return found;
915 }
916 
917 static u64 prio_low = ~0ULL/2;
918 static u64 prio_high = ~0ULL/2 - 1;
919 
920 /* Add rule to given filterlist if not a duplicate. */
921 static inline int audit_add_rule(struct audit_entry *entry)
922 {
923 	struct audit_entry *e;
924 	struct audit_watch *watch = entry->rule.watch;
925 	struct audit_tree *tree = entry->rule.tree;
926 	struct list_head *list;
927 	int err = 0;
928 #ifdef CONFIG_AUDITSYSCALL
929 	int dont_count = 0;
930 
931 	/* If any of these, don't count towards total */
932 	switch(entry->rule.listnr) {
933 	case AUDIT_FILTER_USER:
934 	case AUDIT_FILTER_TYPE:
935 	case AUDIT_FILTER_FS:
936 		dont_count = 1;
937 	}
938 #endif
939 
940 	mutex_lock(&audit_filter_mutex);
941 	e = audit_find_rule(entry, &list);
942 	if (e) {
943 		mutex_unlock(&audit_filter_mutex);
944 		err = -EEXIST;
945 		/* normally audit_add_tree_rule() will free it on failure */
946 		if (tree)
947 			audit_put_tree(tree);
948 		return err;
949 	}
950 
951 	if (watch) {
952 		/* audit_filter_mutex is dropped and re-taken during this call */
953 		err = audit_add_watch(&entry->rule, &list);
954 		if (err) {
955 			mutex_unlock(&audit_filter_mutex);
956 			/*
957 			 * normally audit_add_tree_rule() will free it
958 			 * on failure
959 			 */
960 			if (tree)
961 				audit_put_tree(tree);
962 			return err;
963 		}
964 	}
965 	if (tree) {
966 		err = audit_add_tree_rule(&entry->rule);
967 		if (err) {
968 			mutex_unlock(&audit_filter_mutex);
969 			return err;
970 		}
971 	}
972 
973 	entry->rule.prio = ~0ULL;
974 	if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
975 		if (entry->rule.flags & AUDIT_FILTER_PREPEND)
976 			entry->rule.prio = ++prio_high;
977 		else
978 			entry->rule.prio = --prio_low;
979 	}
980 
981 	if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
982 		list_add(&entry->rule.list,
983 			 &audit_rules_list[entry->rule.listnr]);
984 		list_add_rcu(&entry->list, list);
985 		entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
986 	} else {
987 		list_add_tail(&entry->rule.list,
988 			      &audit_rules_list[entry->rule.listnr]);
989 		list_add_tail_rcu(&entry->list, list);
990 	}
991 #ifdef CONFIG_AUDITSYSCALL
992 	if (!dont_count)
993 		audit_n_rules++;
994 
995 	if (!audit_match_signal(entry))
996 		audit_signals++;
997 #endif
998 	mutex_unlock(&audit_filter_mutex);
999 
1000 	return err;
1001 }
1002 
1003 /* Remove an existing rule from filterlist. */
1004 int audit_del_rule(struct audit_entry *entry)
1005 {
1006 	struct audit_entry  *e;
1007 	struct audit_tree *tree = entry->rule.tree;
1008 	struct list_head *list;
1009 	int ret = 0;
1010 #ifdef CONFIG_AUDITSYSCALL
1011 	int dont_count = 0;
1012 
1013 	/* If any of these, don't count towards total */
1014 	switch(entry->rule.listnr) {
1015 	case AUDIT_FILTER_USER:
1016 	case AUDIT_FILTER_TYPE:
1017 	case AUDIT_FILTER_FS:
1018 		dont_count = 1;
1019 	}
1020 #endif
1021 
1022 	mutex_lock(&audit_filter_mutex);
1023 	e = audit_find_rule(entry, &list);
1024 	if (!e) {
1025 		ret = -ENOENT;
1026 		goto out;
1027 	}
1028 
1029 	if (e->rule.watch)
1030 		audit_remove_watch_rule(&e->rule);
1031 
1032 	if (e->rule.tree)
1033 		audit_remove_tree_rule(&e->rule);
1034 
1035 	if (e->rule.exe)
1036 		audit_remove_mark_rule(&e->rule);
1037 
1038 #ifdef CONFIG_AUDITSYSCALL
1039 	if (!dont_count)
1040 		audit_n_rules--;
1041 
1042 	if (!audit_match_signal(entry))
1043 		audit_signals--;
1044 #endif
1045 
1046 	list_del_rcu(&e->list);
1047 	list_del(&e->rule.list);
1048 	call_rcu(&e->rcu, audit_free_rule_rcu);
1049 
1050 out:
1051 	mutex_unlock(&audit_filter_mutex);
1052 
1053 	if (tree)
1054 		audit_put_tree(tree);	/* that's the temporary one */
1055 
1056 	return ret;
1057 }
1058 
1059 /* List rules using struct audit_rule_data. */
1060 static void audit_list_rules(int seq, struct sk_buff_head *q)
1061 {
1062 	struct sk_buff *skb;
1063 	struct audit_krule *r;
1064 	int i;
1065 
1066 	/* This is a blocking read, so use audit_filter_mutex instead of rcu
1067 	 * iterator to sync with list writers. */
1068 	for (i=0; i<AUDIT_NR_FILTERS; i++) {
1069 		list_for_each_entry(r, &audit_rules_list[i], list) {
1070 			struct audit_rule_data *data;
1071 
1072 			data = audit_krule_to_data(r);
1073 			if (unlikely(!data))
1074 				break;
1075 			skb = audit_make_reply(seq, AUDIT_LIST_RULES, 0, 1,
1076 					       data,
1077 					       sizeof(*data) + data->buflen);
1078 			if (skb)
1079 				skb_queue_tail(q, skb);
1080 			kfree(data);
1081 		}
1082 	}
1083 	skb = audit_make_reply(seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1084 	if (skb)
1085 		skb_queue_tail(q, skb);
1086 }
1087 
1088 /* Log rule additions and removals */
1089 static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
1090 {
1091 	struct audit_buffer *ab;
1092 
1093 	if (!audit_enabled)
1094 		return;
1095 
1096 	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1097 	if (!ab)
1098 		return;
1099 	audit_log_session_info(ab);
1100 	audit_log_task_context(ab);
1101 	audit_log_format(ab, " op=%s", action);
1102 	audit_log_key(ab, rule->filterkey);
1103 	audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1104 	audit_log_end(ab);
1105 }
1106 
1107 /**
1108  * audit_rule_change - apply all rules to the specified message type
1109  * @type: audit message type
1110  * @seq: netlink audit message sequence (serial) number
1111  * @data: payload data
1112  * @datasz: size of payload data
1113  */
1114 int audit_rule_change(int type, int seq, void *data, size_t datasz)
1115 {
1116 	int err = 0;
1117 	struct audit_entry *entry;
1118 
1119 	entry = audit_data_to_entry(data, datasz);
1120 	if (IS_ERR(entry))
1121 		return PTR_ERR(entry);
1122 
1123 	switch (type) {
1124 	case AUDIT_ADD_RULE:
1125 		err = audit_add_rule(entry);
1126 		audit_log_rule_change("add_rule", &entry->rule, !err);
1127 		break;
1128 	case AUDIT_DEL_RULE:
1129 		err = audit_del_rule(entry);
1130 		audit_log_rule_change("remove_rule", &entry->rule, !err);
1131 		break;
1132 	default:
1133 		err = -EINVAL;
1134 		WARN_ON(1);
1135 	}
1136 
1137 	if (err || type == AUDIT_DEL_RULE) {
1138 		if (entry->rule.exe)
1139 			audit_remove_mark(entry->rule.exe);
1140 		audit_free_rule(entry);
1141 	}
1142 
1143 	return err;
1144 }
1145 
1146 /**
1147  * audit_list_rules_send - list the audit rules
1148  * @request_skb: skb of request we are replying to (used to target the reply)
1149  * @seq: netlink audit message sequence (serial) number
1150  */
1151 int audit_list_rules_send(struct sk_buff *request_skb, int seq)
1152 {
1153 	u32 portid = NETLINK_CB(request_skb).portid;
1154 	struct net *net = sock_net(NETLINK_CB(request_skb).sk);
1155 	struct task_struct *tsk;
1156 	struct audit_netlink_list *dest;
1157 	int err = 0;
1158 
1159 	/* We can't just spew out the rules here because we might fill
1160 	 * the available socket buffer space and deadlock waiting for
1161 	 * auditctl to read from it... which isn't ever going to
1162 	 * happen if we're actually running in the context of auditctl
1163 	 * trying to _send_ the stuff */
1164 
1165 	dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1166 	if (!dest)
1167 		return -ENOMEM;
1168 	dest->net = get_net(net);
1169 	dest->portid = portid;
1170 	skb_queue_head_init(&dest->q);
1171 
1172 	mutex_lock(&audit_filter_mutex);
1173 	audit_list_rules(seq, &dest->q);
1174 	mutex_unlock(&audit_filter_mutex);
1175 
1176 	tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1177 	if (IS_ERR(tsk)) {
1178 		skb_queue_purge(&dest->q);
1179 		kfree(dest);
1180 		err = PTR_ERR(tsk);
1181 	}
1182 
1183 	return err;
1184 }
1185 
1186 int audit_comparator(u32 left, u32 op, u32 right)
1187 {
1188 	switch (op) {
1189 	case Audit_equal:
1190 		return (left == right);
1191 	case Audit_not_equal:
1192 		return (left != right);
1193 	case Audit_lt:
1194 		return (left < right);
1195 	case Audit_le:
1196 		return (left <= right);
1197 	case Audit_gt:
1198 		return (left > right);
1199 	case Audit_ge:
1200 		return (left >= right);
1201 	case Audit_bitmask:
1202 		return (left & right);
1203 	case Audit_bittest:
1204 		return ((left & right) == right);
1205 	default:
1206 		BUG();
1207 		return 0;
1208 	}
1209 }
1210 
1211 int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1212 {
1213 	switch (op) {
1214 	case Audit_equal:
1215 		return uid_eq(left, right);
1216 	case Audit_not_equal:
1217 		return !uid_eq(left, right);
1218 	case Audit_lt:
1219 		return uid_lt(left, right);
1220 	case Audit_le:
1221 		return uid_lte(left, right);
1222 	case Audit_gt:
1223 		return uid_gt(left, right);
1224 	case Audit_ge:
1225 		return uid_gte(left, right);
1226 	case Audit_bitmask:
1227 	case Audit_bittest:
1228 	default:
1229 		BUG();
1230 		return 0;
1231 	}
1232 }
1233 
1234 int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1235 {
1236 	switch (op) {
1237 	case Audit_equal:
1238 		return gid_eq(left, right);
1239 	case Audit_not_equal:
1240 		return !gid_eq(left, right);
1241 	case Audit_lt:
1242 		return gid_lt(left, right);
1243 	case Audit_le:
1244 		return gid_lte(left, right);
1245 	case Audit_gt:
1246 		return gid_gt(left, right);
1247 	case Audit_ge:
1248 		return gid_gte(left, right);
1249 	case Audit_bitmask:
1250 	case Audit_bittest:
1251 	default:
1252 		BUG();
1253 		return 0;
1254 	}
1255 }
1256 
1257 /**
1258  * parent_len - find the length of the parent portion of a pathname
1259  * @path: pathname of which to determine length
1260  */
1261 int parent_len(const char *path)
1262 {
1263 	int plen;
1264 	const char *p;
1265 
1266 	plen = strlen(path);
1267 
1268 	if (plen == 0)
1269 		return plen;
1270 
1271 	/* disregard trailing slashes */
1272 	p = path + plen - 1;
1273 	while ((*p == '/') && (p > path))
1274 		p--;
1275 
1276 	/* walk backward until we find the next slash or hit beginning */
1277 	while ((*p != '/') && (p > path))
1278 		p--;
1279 
1280 	/* did we find a slash? Then increment to include it in path */
1281 	if (*p == '/')
1282 		p++;
1283 
1284 	return p - path;
1285 }
1286 
1287 /**
1288  * audit_compare_dname_path - compare given dentry name with last component in
1289  * 			      given path. Return of 0 indicates a match.
1290  * @dname:	dentry name that we're comparing
1291  * @path:	full pathname that we're comparing
1292  * @parentlen:	length of the parent if known. Passing in AUDIT_NAME_FULL
1293  * 		here indicates that we must compute this value.
1294  */
1295 int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
1296 {
1297 	int dlen, pathlen;
1298 	const char *p;
1299 
1300 	dlen = strlen(dname);
1301 	pathlen = strlen(path);
1302 	if (pathlen < dlen)
1303 		return 1;
1304 
1305 	parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1306 	if (pathlen - parentlen != dlen)
1307 		return 1;
1308 
1309 	p = path + parentlen;
1310 
1311 	return strncmp(p, dname, dlen);
1312 }
1313 
1314 int audit_filter(int msgtype, unsigned int listtype)
1315 {
1316 	struct audit_entry *e;
1317 	int ret = 1; /* Audit by default */
1318 
1319 	rcu_read_lock();
1320 	if (list_empty(&audit_filter_list[listtype]))
1321 		goto unlock_and_return;
1322 	list_for_each_entry_rcu(e, &audit_filter_list[listtype], list) {
1323 		int i, result = 0;
1324 
1325 		for (i = 0; i < e->rule.field_count; i++) {
1326 			struct audit_field *f = &e->rule.fields[i];
1327 			pid_t pid;
1328 			u32 sid;
1329 
1330 			switch (f->type) {
1331 			case AUDIT_PID:
1332 				pid = task_pid_nr(current);
1333 				result = audit_comparator(pid, f->op, f->val);
1334 				break;
1335 			case AUDIT_UID:
1336 				result = audit_uid_comparator(current_uid(), f->op, f->uid);
1337 				break;
1338 			case AUDIT_GID:
1339 				result = audit_gid_comparator(current_gid(), f->op, f->gid);
1340 				break;
1341 			case AUDIT_LOGINUID:
1342 				result = audit_uid_comparator(audit_get_loginuid(current),
1343 							      f->op, f->uid);
1344 				break;
1345 			case AUDIT_LOGINUID_SET:
1346 				result = audit_comparator(audit_loginuid_set(current),
1347 							  f->op, f->val);
1348 				break;
1349 			case AUDIT_MSGTYPE:
1350 				result = audit_comparator(msgtype, f->op, f->val);
1351 				break;
1352 			case AUDIT_SUBJ_USER:
1353 			case AUDIT_SUBJ_ROLE:
1354 			case AUDIT_SUBJ_TYPE:
1355 			case AUDIT_SUBJ_SEN:
1356 			case AUDIT_SUBJ_CLR:
1357 				if (f->lsm_rule) {
1358 					security_task_getsecid(current, &sid);
1359 					result = security_audit_rule_match(sid,
1360 							f->type, f->op, f->lsm_rule, NULL);
1361 				}
1362 				break;
1363 			default:
1364 				goto unlock_and_return;
1365 			}
1366 			if (result < 0) /* error */
1367 				goto unlock_and_return;
1368 			if (!result)
1369 				break;
1370 		}
1371 		if (result > 0) {
1372 			if (e->rule.action == AUDIT_NEVER || listtype == AUDIT_FILTER_TYPE)
1373 				ret = 0;
1374 			break;
1375 		}
1376 	}
1377 unlock_and_return:
1378 	rcu_read_unlock();
1379 	return ret;
1380 }
1381 
1382 static int update_lsm_rule(struct audit_krule *r)
1383 {
1384 	struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1385 	struct audit_entry *nentry;
1386 	int err = 0;
1387 
1388 	if (!security_audit_rule_known(r))
1389 		return 0;
1390 
1391 	nentry = audit_dupe_rule(r);
1392 	if (entry->rule.exe)
1393 		audit_remove_mark(entry->rule.exe);
1394 	if (IS_ERR(nentry)) {
1395 		/* save the first error encountered for the
1396 		 * return value */
1397 		err = PTR_ERR(nentry);
1398 		audit_panic("error updating LSM filters");
1399 		if (r->watch)
1400 			list_del(&r->rlist);
1401 		list_del_rcu(&entry->list);
1402 		list_del(&r->list);
1403 	} else {
1404 		if (r->watch || r->tree)
1405 			list_replace_init(&r->rlist, &nentry->rule.rlist);
1406 		list_replace_rcu(&entry->list, &nentry->list);
1407 		list_replace(&r->list, &nentry->rule.list);
1408 	}
1409 	call_rcu(&entry->rcu, audit_free_rule_rcu);
1410 
1411 	return err;
1412 }
1413 
1414 /* This function will re-initialize the lsm_rule field of all applicable rules.
1415  * It will traverse the filter lists serarching for rules that contain LSM
1416  * specific filter fields.  When such a rule is found, it is copied, the
1417  * LSM field is re-initialized, and the old rule is replaced with the
1418  * updated rule. */
1419 int audit_update_lsm_rules(void)
1420 {
1421 	struct audit_krule *r, *n;
1422 	int i, err = 0;
1423 
1424 	/* audit_filter_mutex synchronizes the writers */
1425 	mutex_lock(&audit_filter_mutex);
1426 
1427 	for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1428 		list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1429 			int res = update_lsm_rule(r);
1430 			if (!err)
1431 				err = res;
1432 		}
1433 	}
1434 	mutex_unlock(&audit_filter_mutex);
1435 
1436 	return err;
1437 }
1438