xref: /linux/kernel/auditfilter.c (revision b889fcf63cb62e7fdb7816565e28f44dbe4a76a5)
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 #include <linux/kernel.h>
23 #include <linux/audit.h>
24 #include <linux/kthread.h>
25 #include <linux/mutex.h>
26 #include <linux/fs.h>
27 #include <linux/namei.h>
28 #include <linux/netlink.h>
29 #include <linux/sched.h>
30 #include <linux/slab.h>
31 #include <linux/security.h>
32 #include "audit.h"
33 
34 /*
35  * Locking model:
36  *
37  * audit_filter_mutex:
38  * 		Synchronizes writes and blocking reads of audit's filterlist
39  * 		data.  Rcu is used to traverse the filterlist and access
40  * 		contents of structs audit_entry, audit_watch and opaque
41  * 		LSM rules during filtering.  If modified, these structures
42  * 		must be copied and replace their counterparts in the filterlist.
43  * 		An audit_parent struct is not accessed during filtering, so may
44  * 		be written directly provided audit_filter_mutex is held.
45  */
46 
47 /* Audit filter lists, defined in <linux/audit.h> */
48 struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
49 	LIST_HEAD_INIT(audit_filter_list[0]),
50 	LIST_HEAD_INIT(audit_filter_list[1]),
51 	LIST_HEAD_INIT(audit_filter_list[2]),
52 	LIST_HEAD_INIT(audit_filter_list[3]),
53 	LIST_HEAD_INIT(audit_filter_list[4]),
54 	LIST_HEAD_INIT(audit_filter_list[5]),
55 #if AUDIT_NR_FILTERS != 6
56 #error Fix audit_filter_list initialiser
57 #endif
58 };
59 static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
60 	LIST_HEAD_INIT(audit_rules_list[0]),
61 	LIST_HEAD_INIT(audit_rules_list[1]),
62 	LIST_HEAD_INIT(audit_rules_list[2]),
63 	LIST_HEAD_INIT(audit_rules_list[3]),
64 	LIST_HEAD_INIT(audit_rules_list[4]),
65 	LIST_HEAD_INIT(audit_rules_list[5]),
66 };
67 
68 DEFINE_MUTEX(audit_filter_mutex);
69 
70 static inline void audit_free_rule(struct audit_entry *e)
71 {
72 	int i;
73 	struct audit_krule *erule = &e->rule;
74 
75 	/* some rules don't have associated watches */
76 	if (erule->watch)
77 		audit_put_watch(erule->watch);
78 	if (erule->fields)
79 		for (i = 0; i < erule->field_count; i++) {
80 			struct audit_field *f = &erule->fields[i];
81 			kfree(f->lsm_str);
82 			security_audit_rule_free(f->lsm_rule);
83 		}
84 	kfree(erule->fields);
85 	kfree(erule->filterkey);
86 	kfree(e);
87 }
88 
89 void audit_free_rule_rcu(struct rcu_head *head)
90 {
91 	struct audit_entry *e = container_of(head, struct audit_entry, rcu);
92 	audit_free_rule(e);
93 }
94 
95 /* Initialize an audit filterlist entry. */
96 static inline struct audit_entry *audit_init_entry(u32 field_count)
97 {
98 	struct audit_entry *entry;
99 	struct audit_field *fields;
100 
101 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
102 	if (unlikely(!entry))
103 		return NULL;
104 
105 	fields = kzalloc(sizeof(*fields) * field_count, GFP_KERNEL);
106 	if (unlikely(!fields)) {
107 		kfree(entry);
108 		return NULL;
109 	}
110 	entry->rule.fields = fields;
111 
112 	return entry;
113 }
114 
115 /* Unpack a filter field's string representation from user-space
116  * buffer. */
117 char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
118 {
119 	char *str;
120 
121 	if (!*bufp || (len == 0) || (len > *remain))
122 		return ERR_PTR(-EINVAL);
123 
124 	/* Of the currently implemented string fields, PATH_MAX
125 	 * defines the longest valid length.
126 	 */
127 	if (len > PATH_MAX)
128 		return ERR_PTR(-ENAMETOOLONG);
129 
130 	str = kmalloc(len + 1, GFP_KERNEL);
131 	if (unlikely(!str))
132 		return ERR_PTR(-ENOMEM);
133 
134 	memcpy(str, *bufp, len);
135 	str[len] = 0;
136 	*bufp += len;
137 	*remain -= len;
138 
139 	return str;
140 }
141 
142 /* Translate an inode field to kernel respresentation. */
143 static inline int audit_to_inode(struct audit_krule *krule,
144 				 struct audit_field *f)
145 {
146 	if (krule->listnr != AUDIT_FILTER_EXIT ||
147 	    krule->watch || krule->inode_f || krule->tree ||
148 	    (f->op != Audit_equal && f->op != Audit_not_equal))
149 		return -EINVAL;
150 
151 	krule->inode_f = f;
152 	return 0;
153 }
154 
155 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
156 
157 int __init audit_register_class(int class, unsigned *list)
158 {
159 	__u32 *p = kzalloc(AUDIT_BITMASK_SIZE * sizeof(__u32), GFP_KERNEL);
160 	if (!p)
161 		return -ENOMEM;
162 	while (*list != ~0U) {
163 		unsigned n = *list++;
164 		if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
165 			kfree(p);
166 			return -EINVAL;
167 		}
168 		p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
169 	}
170 	if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
171 		kfree(p);
172 		return -EINVAL;
173 	}
174 	classes[class] = p;
175 	return 0;
176 }
177 
178 int audit_match_class(int class, unsigned syscall)
179 {
180 	if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
181 		return 0;
182 	if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
183 		return 0;
184 	return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
185 }
186 
187 #ifdef CONFIG_AUDITSYSCALL
188 static inline int audit_match_class_bits(int class, u32 *mask)
189 {
190 	int i;
191 
192 	if (classes[class]) {
193 		for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
194 			if (mask[i] & classes[class][i])
195 				return 0;
196 	}
197 	return 1;
198 }
199 
200 static int audit_match_signal(struct audit_entry *entry)
201 {
202 	struct audit_field *arch = entry->rule.arch_f;
203 
204 	if (!arch) {
205 		/* When arch is unspecified, we must check both masks on biarch
206 		 * as syscall number alone is ambiguous. */
207 		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
208 					       entry->rule.mask) &&
209 			audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
210 					       entry->rule.mask));
211 	}
212 
213 	switch(audit_classify_arch(arch->val)) {
214 	case 0: /* native */
215 		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
216 					       entry->rule.mask));
217 	case 1: /* 32bit on biarch */
218 		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
219 					       entry->rule.mask));
220 	default:
221 		return 1;
222 	}
223 }
224 #endif
225 
226 /* Common user-space to kernel rule translation. */
227 static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule)
228 {
229 	unsigned listnr;
230 	struct audit_entry *entry;
231 	int i, err;
232 
233 	err = -EINVAL;
234 	listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
235 	switch(listnr) {
236 	default:
237 		goto exit_err;
238 #ifdef CONFIG_AUDITSYSCALL
239 	case AUDIT_FILTER_ENTRY:
240 		if (rule->action == AUDIT_ALWAYS)
241 			goto exit_err;
242 	case AUDIT_FILTER_EXIT:
243 	case AUDIT_FILTER_TASK:
244 #endif
245 	case AUDIT_FILTER_USER:
246 	case AUDIT_FILTER_TYPE:
247 		;
248 	}
249 	if (unlikely(rule->action == AUDIT_POSSIBLE)) {
250 		printk(KERN_ERR "AUDIT_POSSIBLE is deprecated\n");
251 		goto exit_err;
252 	}
253 	if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
254 		goto exit_err;
255 	if (rule->field_count > AUDIT_MAX_FIELDS)
256 		goto exit_err;
257 
258 	err = -ENOMEM;
259 	entry = audit_init_entry(rule->field_count);
260 	if (!entry)
261 		goto exit_err;
262 
263 	entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
264 	entry->rule.listnr = listnr;
265 	entry->rule.action = rule->action;
266 	entry->rule.field_count = rule->field_count;
267 
268 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
269 		entry->rule.mask[i] = rule->mask[i];
270 
271 	for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
272 		int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
273 		__u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
274 		__u32 *class;
275 
276 		if (!(*p & AUDIT_BIT(bit)))
277 			continue;
278 		*p &= ~AUDIT_BIT(bit);
279 		class = classes[i];
280 		if (class) {
281 			int j;
282 			for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
283 				entry->rule.mask[j] |= class[j];
284 		}
285 	}
286 
287 	return entry;
288 
289 exit_err:
290 	return ERR_PTR(err);
291 }
292 
293 static u32 audit_ops[] =
294 {
295 	[Audit_equal] = AUDIT_EQUAL,
296 	[Audit_not_equal] = AUDIT_NOT_EQUAL,
297 	[Audit_bitmask] = AUDIT_BIT_MASK,
298 	[Audit_bittest] = AUDIT_BIT_TEST,
299 	[Audit_lt] = AUDIT_LESS_THAN,
300 	[Audit_gt] = AUDIT_GREATER_THAN,
301 	[Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
302 	[Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
303 };
304 
305 static u32 audit_to_op(u32 op)
306 {
307 	u32 n;
308 	for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
309 		;
310 	return n;
311 }
312 
313 
314 /* Translate struct audit_rule to kernel's rule respresentation.
315  * Exists for backward compatibility with userspace. */
316 static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
317 {
318 	struct audit_entry *entry;
319 	int err = 0;
320 	int i;
321 
322 	entry = audit_to_entry_common(rule);
323 	if (IS_ERR(entry))
324 		goto exit_nofree;
325 
326 	for (i = 0; i < rule->field_count; i++) {
327 		struct audit_field *f = &entry->rule.fields[i];
328 		u32 n;
329 
330 		n = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS);
331 
332 		/* Support for legacy operators where
333 		 * AUDIT_NEGATE bit signifies != and otherwise assumes == */
334 		if (n & AUDIT_NEGATE)
335 			f->op = Audit_not_equal;
336 		else if (!n)
337 			f->op = Audit_equal;
338 		else
339 			f->op = audit_to_op(n);
340 
341 		entry->rule.vers_ops = (n & AUDIT_OPERATORS) ? 2 : 1;
342 
343 		f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS);
344 		f->val = rule->values[i];
345 		f->uid = INVALID_UID;
346 		f->gid = INVALID_GID;
347 
348 		err = -EINVAL;
349 		if (f->op == Audit_bad)
350 			goto exit_free;
351 
352 		switch(f->type) {
353 		default:
354 			goto exit_free;
355 		case AUDIT_UID:
356 		case AUDIT_EUID:
357 		case AUDIT_SUID:
358 		case AUDIT_FSUID:
359 		case AUDIT_LOGINUID:
360 			/* bit ops not implemented for uid comparisons */
361 			if (f->op == Audit_bitmask || f->op == Audit_bittest)
362 				goto exit_free;
363 
364 			f->uid = make_kuid(current_user_ns(), f->val);
365 			if (!uid_valid(f->uid))
366 				goto exit_free;
367 			break;
368 		case AUDIT_GID:
369 		case AUDIT_EGID:
370 		case AUDIT_SGID:
371 		case AUDIT_FSGID:
372 			/* bit ops not implemented for gid comparisons */
373 			if (f->op == Audit_bitmask || f->op == Audit_bittest)
374 				goto exit_free;
375 
376 			f->gid = make_kgid(current_user_ns(), f->val);
377 			if (!gid_valid(f->gid))
378 				goto exit_free;
379 			break;
380 		case AUDIT_PID:
381 		case AUDIT_PERS:
382 		case AUDIT_MSGTYPE:
383 		case AUDIT_PPID:
384 		case AUDIT_DEVMAJOR:
385 		case AUDIT_DEVMINOR:
386 		case AUDIT_EXIT:
387 		case AUDIT_SUCCESS:
388 			/* bit ops are only useful on syscall args */
389 			if (f->op == Audit_bitmask || f->op == Audit_bittest)
390 				goto exit_free;
391 			break;
392 		case AUDIT_ARG0:
393 		case AUDIT_ARG1:
394 		case AUDIT_ARG2:
395 		case AUDIT_ARG3:
396 			break;
397 		/* arch is only allowed to be = or != */
398 		case AUDIT_ARCH:
399 			if (f->op != Audit_not_equal && f->op != Audit_equal)
400 				goto exit_free;
401 			entry->rule.arch_f = f;
402 			break;
403 		case AUDIT_PERM:
404 			if (f->val & ~15)
405 				goto exit_free;
406 			break;
407 		case AUDIT_FILETYPE:
408 			if (f->val & ~S_IFMT)
409 				goto exit_free;
410 			break;
411 		case AUDIT_INODE:
412 			err = audit_to_inode(&entry->rule, f);
413 			if (err)
414 				goto exit_free;
415 			break;
416 		}
417 	}
418 
419 	if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
420 		entry->rule.inode_f = NULL;
421 
422 exit_nofree:
423 	return entry;
424 
425 exit_free:
426 	audit_free_rule(entry);
427 	return ERR_PTR(err);
428 }
429 
430 /* Translate struct audit_rule_data to kernel's rule respresentation. */
431 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
432 					       size_t datasz)
433 {
434 	int err = 0;
435 	struct audit_entry *entry;
436 	void *bufp;
437 	size_t remain = datasz - sizeof(struct audit_rule_data);
438 	int i;
439 	char *str;
440 
441 	entry = audit_to_entry_common((struct audit_rule *)data);
442 	if (IS_ERR(entry))
443 		goto exit_nofree;
444 
445 	bufp = data->buf;
446 	entry->rule.vers_ops = 2;
447 	for (i = 0; i < data->field_count; i++) {
448 		struct audit_field *f = &entry->rule.fields[i];
449 
450 		err = -EINVAL;
451 
452 		f->op = audit_to_op(data->fieldflags[i]);
453 		if (f->op == Audit_bad)
454 			goto exit_free;
455 
456 		f->type = data->fields[i];
457 		f->val = data->values[i];
458 		f->uid = INVALID_UID;
459 		f->gid = INVALID_GID;
460 		f->lsm_str = NULL;
461 		f->lsm_rule = NULL;
462 		switch(f->type) {
463 		case AUDIT_UID:
464 		case AUDIT_EUID:
465 		case AUDIT_SUID:
466 		case AUDIT_FSUID:
467 		case AUDIT_LOGINUID:
468 		case AUDIT_OBJ_UID:
469 			/* bit ops not implemented for uid comparisons */
470 			if (f->op == Audit_bitmask || f->op == Audit_bittest)
471 				goto exit_free;
472 
473 			f->uid = make_kuid(current_user_ns(), f->val);
474 			if (!uid_valid(f->uid))
475 				goto exit_free;
476 			break;
477 		case AUDIT_GID:
478 		case AUDIT_EGID:
479 		case AUDIT_SGID:
480 		case AUDIT_FSGID:
481 		case AUDIT_OBJ_GID:
482 			/* bit ops not implemented for gid comparisons */
483 			if (f->op == Audit_bitmask || f->op == Audit_bittest)
484 				goto exit_free;
485 
486 			f->gid = make_kgid(current_user_ns(), f->val);
487 			if (!gid_valid(f->gid))
488 				goto exit_free;
489 			break;
490 		case AUDIT_PID:
491 		case AUDIT_PERS:
492 		case AUDIT_MSGTYPE:
493 		case AUDIT_PPID:
494 		case AUDIT_DEVMAJOR:
495 		case AUDIT_DEVMINOR:
496 		case AUDIT_EXIT:
497 		case AUDIT_SUCCESS:
498 		case AUDIT_ARG0:
499 		case AUDIT_ARG1:
500 		case AUDIT_ARG2:
501 		case AUDIT_ARG3:
502 			break;
503 		case AUDIT_ARCH:
504 			entry->rule.arch_f = f;
505 			break;
506 		case AUDIT_SUBJ_USER:
507 		case AUDIT_SUBJ_ROLE:
508 		case AUDIT_SUBJ_TYPE:
509 		case AUDIT_SUBJ_SEN:
510 		case AUDIT_SUBJ_CLR:
511 		case AUDIT_OBJ_USER:
512 		case AUDIT_OBJ_ROLE:
513 		case AUDIT_OBJ_TYPE:
514 		case AUDIT_OBJ_LEV_LOW:
515 		case AUDIT_OBJ_LEV_HIGH:
516 			str = audit_unpack_string(&bufp, &remain, f->val);
517 			if (IS_ERR(str))
518 				goto exit_free;
519 			entry->rule.buflen += f->val;
520 
521 			err = security_audit_rule_init(f->type, f->op, str,
522 						       (void **)&f->lsm_rule);
523 			/* Keep currently invalid fields around in case they
524 			 * become valid after a policy reload. */
525 			if (err == -EINVAL) {
526 				printk(KERN_WARNING "audit rule for LSM "
527 				       "\'%s\' is invalid\n",  str);
528 				err = 0;
529 			}
530 			if (err) {
531 				kfree(str);
532 				goto exit_free;
533 			} else
534 				f->lsm_str = str;
535 			break;
536 		case AUDIT_WATCH:
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 
542 			err = audit_to_watch(&entry->rule, str, f->val, f->op);
543 			if (err) {
544 				kfree(str);
545 				goto exit_free;
546 			}
547 			break;
548 		case AUDIT_DIR:
549 			str = audit_unpack_string(&bufp, &remain, f->val);
550 			if (IS_ERR(str))
551 				goto exit_free;
552 			entry->rule.buflen += f->val;
553 
554 			err = audit_make_tree(&entry->rule, str, f->op);
555 			kfree(str);
556 			if (err)
557 				goto exit_free;
558 			break;
559 		case AUDIT_INODE:
560 			err = audit_to_inode(&entry->rule, f);
561 			if (err)
562 				goto exit_free;
563 			break;
564 		case AUDIT_FILTERKEY:
565 			if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
566 				goto exit_free;
567 			str = audit_unpack_string(&bufp, &remain, f->val);
568 			if (IS_ERR(str))
569 				goto exit_free;
570 			entry->rule.buflen += f->val;
571 			entry->rule.filterkey = str;
572 			break;
573 		case AUDIT_PERM:
574 			if (f->val & ~15)
575 				goto exit_free;
576 			break;
577 		case AUDIT_FILETYPE:
578 			if (f->val & ~S_IFMT)
579 				goto exit_free;
580 			break;
581 		case AUDIT_FIELD_COMPARE:
582 			if (f->val > AUDIT_MAX_FIELD_COMPARE)
583 				goto exit_free;
584 			break;
585 		default:
586 			goto exit_free;
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 	audit_free_rule(entry);
598 	return ERR_PTR(err);
599 }
600 
601 /* Pack a filter field's string representation into data block. */
602 static inline size_t audit_pack_string(void **bufp, const char *str)
603 {
604 	size_t len = strlen(str);
605 
606 	memcpy(*bufp, str, len);
607 	*bufp += len;
608 
609 	return len;
610 }
611 
612 /* Translate kernel rule respresentation to struct audit_rule.
613  * Exists for backward compatibility with userspace. */
614 static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
615 {
616 	struct audit_rule *rule;
617 	int i;
618 
619 	rule = kzalloc(sizeof(*rule), GFP_KERNEL);
620 	if (unlikely(!rule))
621 		return NULL;
622 
623 	rule->flags = krule->flags | krule->listnr;
624 	rule->action = krule->action;
625 	rule->field_count = krule->field_count;
626 	for (i = 0; i < rule->field_count; i++) {
627 		rule->values[i] = krule->fields[i].val;
628 		rule->fields[i] = krule->fields[i].type;
629 
630 		if (krule->vers_ops == 1) {
631 			if (krule->fields[i].op == Audit_not_equal)
632 				rule->fields[i] |= AUDIT_NEGATE;
633 		} else {
634 			rule->fields[i] |= audit_ops[krule->fields[i].op];
635 		}
636 	}
637 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
638 
639 	return rule;
640 }
641 
642 /* Translate kernel rule respresentation to struct audit_rule_data. */
643 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
644 {
645 	struct audit_rule_data *data;
646 	void *bufp;
647 	int i;
648 
649 	data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
650 	if (unlikely(!data))
651 		return NULL;
652 	memset(data, 0, sizeof(*data));
653 
654 	data->flags = krule->flags | krule->listnr;
655 	data->action = krule->action;
656 	data->field_count = krule->field_count;
657 	bufp = data->buf;
658 	for (i = 0; i < data->field_count; i++) {
659 		struct audit_field *f = &krule->fields[i];
660 
661 		data->fields[i] = f->type;
662 		data->fieldflags[i] = audit_ops[f->op];
663 		switch(f->type) {
664 		case AUDIT_SUBJ_USER:
665 		case AUDIT_SUBJ_ROLE:
666 		case AUDIT_SUBJ_TYPE:
667 		case AUDIT_SUBJ_SEN:
668 		case AUDIT_SUBJ_CLR:
669 		case AUDIT_OBJ_USER:
670 		case AUDIT_OBJ_ROLE:
671 		case AUDIT_OBJ_TYPE:
672 		case AUDIT_OBJ_LEV_LOW:
673 		case AUDIT_OBJ_LEV_HIGH:
674 			data->buflen += data->values[i] =
675 				audit_pack_string(&bufp, f->lsm_str);
676 			break;
677 		case AUDIT_WATCH:
678 			data->buflen += data->values[i] =
679 				audit_pack_string(&bufp,
680 						  audit_watch_path(krule->watch));
681 			break;
682 		case AUDIT_DIR:
683 			data->buflen += data->values[i] =
684 				audit_pack_string(&bufp,
685 						  audit_tree_path(krule->tree));
686 			break;
687 		case AUDIT_FILTERKEY:
688 			data->buflen += data->values[i] =
689 				audit_pack_string(&bufp, krule->filterkey);
690 			break;
691 		default:
692 			data->values[i] = f->val;
693 		}
694 	}
695 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
696 
697 	return data;
698 }
699 
700 /* Compare two rules in kernel format.  Considered success if rules
701  * don't match. */
702 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
703 {
704 	int i;
705 
706 	if (a->flags != b->flags ||
707 	    a->listnr != b->listnr ||
708 	    a->action != b->action ||
709 	    a->field_count != b->field_count)
710 		return 1;
711 
712 	for (i = 0; i < a->field_count; i++) {
713 		if (a->fields[i].type != b->fields[i].type ||
714 		    a->fields[i].op != b->fields[i].op)
715 			return 1;
716 
717 		switch(a->fields[i].type) {
718 		case AUDIT_SUBJ_USER:
719 		case AUDIT_SUBJ_ROLE:
720 		case AUDIT_SUBJ_TYPE:
721 		case AUDIT_SUBJ_SEN:
722 		case AUDIT_SUBJ_CLR:
723 		case AUDIT_OBJ_USER:
724 		case AUDIT_OBJ_ROLE:
725 		case AUDIT_OBJ_TYPE:
726 		case AUDIT_OBJ_LEV_LOW:
727 		case AUDIT_OBJ_LEV_HIGH:
728 			if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
729 				return 1;
730 			break;
731 		case AUDIT_WATCH:
732 			if (strcmp(audit_watch_path(a->watch),
733 				   audit_watch_path(b->watch)))
734 				return 1;
735 			break;
736 		case AUDIT_DIR:
737 			if (strcmp(audit_tree_path(a->tree),
738 				   audit_tree_path(b->tree)))
739 				return 1;
740 			break;
741 		case AUDIT_FILTERKEY:
742 			/* both filterkeys exist based on above type compare */
743 			if (strcmp(a->filterkey, b->filterkey))
744 				return 1;
745 			break;
746 		case AUDIT_UID:
747 		case AUDIT_EUID:
748 		case AUDIT_SUID:
749 		case AUDIT_FSUID:
750 		case AUDIT_LOGINUID:
751 		case AUDIT_OBJ_UID:
752 			if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
753 				return 1;
754 			break;
755 		case AUDIT_GID:
756 		case AUDIT_EGID:
757 		case AUDIT_SGID:
758 		case AUDIT_FSGID:
759 		case AUDIT_OBJ_GID:
760 			if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
761 				return 1;
762 			break;
763 		default:
764 			if (a->fields[i].val != b->fields[i].val)
765 				return 1;
766 		}
767 	}
768 
769 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
770 		if (a->mask[i] != b->mask[i])
771 			return 1;
772 
773 	return 0;
774 }
775 
776 /* Duplicate LSM field information.  The lsm_rule is opaque, so must be
777  * re-initialized. */
778 static inline int audit_dupe_lsm_field(struct audit_field *df,
779 					   struct audit_field *sf)
780 {
781 	int ret = 0;
782 	char *lsm_str;
783 
784 	/* our own copy of lsm_str */
785 	lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
786 	if (unlikely(!lsm_str))
787 		return -ENOMEM;
788 	df->lsm_str = lsm_str;
789 
790 	/* our own (refreshed) copy of lsm_rule */
791 	ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
792 				       (void **)&df->lsm_rule);
793 	/* Keep currently invalid fields around in case they
794 	 * become valid after a policy reload. */
795 	if (ret == -EINVAL) {
796 		printk(KERN_WARNING "audit rule for LSM \'%s\' is "
797 		       "invalid\n", df->lsm_str);
798 		ret = 0;
799 	}
800 
801 	return ret;
802 }
803 
804 /* Duplicate an audit rule.  This will be a deep copy with the exception
805  * of the watch - that pointer is carried over.  The LSM specific fields
806  * will be updated in the copy.  The point is to be able to replace the old
807  * rule with the new rule in the filterlist, then free the old rule.
808  * The rlist element is undefined; list manipulations are handled apart from
809  * the initial copy. */
810 struct audit_entry *audit_dupe_rule(struct audit_krule *old)
811 {
812 	u32 fcount = old->field_count;
813 	struct audit_entry *entry;
814 	struct audit_krule *new;
815 	char *fk;
816 	int i, err = 0;
817 
818 	entry = audit_init_entry(fcount);
819 	if (unlikely(!entry))
820 		return ERR_PTR(-ENOMEM);
821 
822 	new = &entry->rule;
823 	new->vers_ops = old->vers_ops;
824 	new->flags = old->flags;
825 	new->listnr = old->listnr;
826 	new->action = old->action;
827 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
828 		new->mask[i] = old->mask[i];
829 	new->prio = old->prio;
830 	new->buflen = old->buflen;
831 	new->inode_f = old->inode_f;
832 	new->field_count = old->field_count;
833 
834 	/*
835 	 * note that we are OK with not refcounting here; audit_match_tree()
836 	 * never dereferences tree and we can't get false positives there
837 	 * since we'd have to have rule gone from the list *and* removed
838 	 * before the chunks found by lookup had been allocated, i.e. before
839 	 * the beginning of list scan.
840 	 */
841 	new->tree = old->tree;
842 	memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
843 
844 	/* deep copy this information, updating the lsm_rule fields, because
845 	 * the originals will all be freed when the old rule is freed. */
846 	for (i = 0; i < fcount; i++) {
847 		switch (new->fields[i].type) {
848 		case AUDIT_SUBJ_USER:
849 		case AUDIT_SUBJ_ROLE:
850 		case AUDIT_SUBJ_TYPE:
851 		case AUDIT_SUBJ_SEN:
852 		case AUDIT_SUBJ_CLR:
853 		case AUDIT_OBJ_USER:
854 		case AUDIT_OBJ_ROLE:
855 		case AUDIT_OBJ_TYPE:
856 		case AUDIT_OBJ_LEV_LOW:
857 		case AUDIT_OBJ_LEV_HIGH:
858 			err = audit_dupe_lsm_field(&new->fields[i],
859 						       &old->fields[i]);
860 			break;
861 		case AUDIT_FILTERKEY:
862 			fk = kstrdup(old->filterkey, GFP_KERNEL);
863 			if (unlikely(!fk))
864 				err = -ENOMEM;
865 			else
866 				new->filterkey = fk;
867 		}
868 		if (err) {
869 			audit_free_rule(entry);
870 			return ERR_PTR(err);
871 		}
872 	}
873 
874 	if (old->watch) {
875 		audit_get_watch(old->watch);
876 		new->watch = old->watch;
877 	}
878 
879 	return entry;
880 }
881 
882 /* Find an existing audit rule.
883  * Caller must hold audit_filter_mutex to prevent stale rule data. */
884 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
885 					   struct list_head **p)
886 {
887 	struct audit_entry *e, *found = NULL;
888 	struct list_head *list;
889 	int h;
890 
891 	if (entry->rule.inode_f) {
892 		h = audit_hash_ino(entry->rule.inode_f->val);
893 		*p = list = &audit_inode_hash[h];
894 	} else if (entry->rule.watch) {
895 		/* we don't know the inode number, so must walk entire hash */
896 		for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
897 			list = &audit_inode_hash[h];
898 			list_for_each_entry(e, list, list)
899 				if (!audit_compare_rule(&entry->rule, &e->rule)) {
900 					found = e;
901 					goto out;
902 				}
903 		}
904 		goto out;
905 	} else {
906 		*p = list = &audit_filter_list[entry->rule.listnr];
907 	}
908 
909 	list_for_each_entry(e, list, list)
910 		if (!audit_compare_rule(&entry->rule, &e->rule)) {
911 			found = e;
912 			goto out;
913 		}
914 
915 out:
916 	return found;
917 }
918 
919 static u64 prio_low = ~0ULL/2;
920 static u64 prio_high = ~0ULL/2 - 1;
921 
922 /* Add rule to given filterlist if not a duplicate. */
923 static inline int audit_add_rule(struct audit_entry *entry)
924 {
925 	struct audit_entry *e;
926 	struct audit_watch *watch = entry->rule.watch;
927 	struct audit_tree *tree = entry->rule.tree;
928 	struct list_head *list;
929 	int err;
930 #ifdef CONFIG_AUDITSYSCALL
931 	int dont_count = 0;
932 
933 	/* If either of these, don't count towards total */
934 	if (entry->rule.listnr == AUDIT_FILTER_USER ||
935 		entry->rule.listnr == AUDIT_FILTER_TYPE)
936 		dont_count = 1;
937 #endif
938 
939 	mutex_lock(&audit_filter_mutex);
940 	e = audit_find_rule(entry, &list);
941 	if (e) {
942 		mutex_unlock(&audit_filter_mutex);
943 		err = -EEXIST;
944 		/* normally audit_add_tree_rule() will free it on failure */
945 		if (tree)
946 			audit_put_tree(tree);
947 		goto error;
948 	}
949 
950 	if (watch) {
951 		/* audit_filter_mutex is dropped and re-taken during this call */
952 		err = audit_add_watch(&entry->rule, &list);
953 		if (err) {
954 			mutex_unlock(&audit_filter_mutex);
955 			goto error;
956 		}
957 	}
958 	if (tree) {
959 		err = audit_add_tree_rule(&entry->rule);
960 		if (err) {
961 			mutex_unlock(&audit_filter_mutex);
962 			goto error;
963 		}
964 	}
965 
966 	entry->rule.prio = ~0ULL;
967 	if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
968 		if (entry->rule.flags & AUDIT_FILTER_PREPEND)
969 			entry->rule.prio = ++prio_high;
970 		else
971 			entry->rule.prio = --prio_low;
972 	}
973 
974 	if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
975 		list_add(&entry->rule.list,
976 			 &audit_rules_list[entry->rule.listnr]);
977 		list_add_rcu(&entry->list, list);
978 		entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
979 	} else {
980 		list_add_tail(&entry->rule.list,
981 			      &audit_rules_list[entry->rule.listnr]);
982 		list_add_tail_rcu(&entry->list, list);
983 	}
984 #ifdef CONFIG_AUDITSYSCALL
985 	if (!dont_count)
986 		audit_n_rules++;
987 
988 	if (!audit_match_signal(entry))
989 		audit_signals++;
990 #endif
991 	mutex_unlock(&audit_filter_mutex);
992 
993  	return 0;
994 
995 error:
996 	if (watch)
997 		audit_put_watch(watch); /* tmp watch, matches initial get */
998 	return err;
999 }
1000 
1001 /* Remove an existing rule from filterlist. */
1002 static inline int audit_del_rule(struct audit_entry *entry)
1003 {
1004 	struct audit_entry  *e;
1005 	struct audit_watch *watch = entry->rule.watch;
1006 	struct audit_tree *tree = entry->rule.tree;
1007 	struct list_head *list;
1008 	int ret = 0;
1009 #ifdef CONFIG_AUDITSYSCALL
1010 	int dont_count = 0;
1011 
1012 	/* If either of these, don't count towards total */
1013 	if (entry->rule.listnr == AUDIT_FILTER_USER ||
1014 		entry->rule.listnr == AUDIT_FILTER_TYPE)
1015 		dont_count = 1;
1016 #endif
1017 
1018 	mutex_lock(&audit_filter_mutex);
1019 	e = audit_find_rule(entry, &list);
1020 	if (!e) {
1021 		mutex_unlock(&audit_filter_mutex);
1022 		ret = -ENOENT;
1023 		goto out;
1024 	}
1025 
1026 	if (e->rule.watch)
1027 		audit_remove_watch_rule(&e->rule);
1028 
1029 	if (e->rule.tree)
1030 		audit_remove_tree_rule(&e->rule);
1031 
1032 	list_del_rcu(&e->list);
1033 	list_del(&e->rule.list);
1034 	call_rcu(&e->rcu, audit_free_rule_rcu);
1035 
1036 #ifdef CONFIG_AUDITSYSCALL
1037 	if (!dont_count)
1038 		audit_n_rules--;
1039 
1040 	if (!audit_match_signal(entry))
1041 		audit_signals--;
1042 #endif
1043 	mutex_unlock(&audit_filter_mutex);
1044 
1045 out:
1046 	if (watch)
1047 		audit_put_watch(watch); /* match initial get */
1048 	if (tree)
1049 		audit_put_tree(tree);	/* that's the temporary one */
1050 
1051 	return ret;
1052 }
1053 
1054 /* List rules using struct audit_rule.  Exists for backward
1055  * compatibility with userspace. */
1056 static void audit_list(int pid, int seq, struct sk_buff_head *q)
1057 {
1058 	struct sk_buff *skb;
1059 	struct audit_krule *r;
1060 	int i;
1061 
1062 	/* This is a blocking read, so use audit_filter_mutex instead of rcu
1063 	 * iterator to sync with list writers. */
1064 	for (i=0; i<AUDIT_NR_FILTERS; i++) {
1065 		list_for_each_entry(r, &audit_rules_list[i], list) {
1066 			struct audit_rule *rule;
1067 
1068 			rule = audit_krule_to_rule(r);
1069 			if (unlikely(!rule))
1070 				break;
1071 			skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1072 					 rule, sizeof(*rule));
1073 			if (skb)
1074 				skb_queue_tail(q, skb);
1075 			kfree(rule);
1076 		}
1077 	}
1078 	skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
1079 	if (skb)
1080 		skb_queue_tail(q, skb);
1081 }
1082 
1083 /* List rules using struct audit_rule_data. */
1084 static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
1085 {
1086 	struct sk_buff *skb;
1087 	struct audit_krule *r;
1088 	int i;
1089 
1090 	/* This is a blocking read, so use audit_filter_mutex instead of rcu
1091 	 * iterator to sync with list writers. */
1092 	for (i=0; i<AUDIT_NR_FILTERS; i++) {
1093 		list_for_each_entry(r, &audit_rules_list[i], list) {
1094 			struct audit_rule_data *data;
1095 
1096 			data = audit_krule_to_data(r);
1097 			if (unlikely(!data))
1098 				break;
1099 			skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1100 					 data, sizeof(*data) + data->buflen);
1101 			if (skb)
1102 				skb_queue_tail(q, skb);
1103 			kfree(data);
1104 		}
1105 	}
1106 	skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1107 	if (skb)
1108 		skb_queue_tail(q, skb);
1109 }
1110 
1111 /* Log rule additions and removals */
1112 static void audit_log_rule_change(kuid_t loginuid, u32 sessionid, u32 sid,
1113 				  char *action, struct audit_krule *rule,
1114 				  int res)
1115 {
1116 	struct audit_buffer *ab;
1117 
1118 	if (!audit_enabled)
1119 		return;
1120 
1121 	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1122 	if (!ab)
1123 		return;
1124 	audit_log_format(ab, "auid=%u ses=%u",
1125 			 from_kuid(&init_user_ns, loginuid), sessionid);
1126 	if (sid) {
1127 		char *ctx = NULL;
1128 		u32 len;
1129 		if (security_secid_to_secctx(sid, &ctx, &len))
1130 			audit_log_format(ab, " ssid=%u", sid);
1131 		else {
1132 			audit_log_format(ab, " subj=%s", ctx);
1133 			security_release_secctx(ctx, len);
1134 		}
1135 	}
1136 	audit_log_format(ab, " op=");
1137 	audit_log_string(ab, action);
1138 	audit_log_key(ab, rule->filterkey);
1139 	audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1140 	audit_log_end(ab);
1141 }
1142 
1143 /**
1144  * audit_receive_filter - apply all rules to the specified message type
1145  * @type: audit message type
1146  * @pid: target pid for netlink audit messages
1147  * @uid: target uid for netlink audit messages
1148  * @seq: netlink audit message sequence (serial) number
1149  * @data: payload data
1150  * @datasz: size of payload data
1151  * @loginuid: loginuid of sender
1152  * @sessionid: sessionid for netlink audit message
1153  * @sid: SE Linux Security ID of sender
1154  */
1155 int audit_receive_filter(int type, int pid, int seq, void *data,
1156 			 size_t datasz, kuid_t loginuid, u32 sessionid, u32 sid)
1157 {
1158 	struct task_struct *tsk;
1159 	struct audit_netlink_list *dest;
1160 	int err = 0;
1161 	struct audit_entry *entry;
1162 
1163 	switch (type) {
1164 	case AUDIT_LIST:
1165 	case AUDIT_LIST_RULES:
1166 		/* We can't just spew out the rules here because we might fill
1167 		 * the available socket buffer space and deadlock waiting for
1168 		 * auditctl to read from it... which isn't ever going to
1169 		 * happen if we're actually running in the context of auditctl
1170 		 * trying to _send_ the stuff */
1171 
1172 		dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1173 		if (!dest)
1174 			return -ENOMEM;
1175 		dest->pid = pid;
1176 		skb_queue_head_init(&dest->q);
1177 
1178 		mutex_lock(&audit_filter_mutex);
1179 		if (type == AUDIT_LIST)
1180 			audit_list(pid, seq, &dest->q);
1181 		else
1182 			audit_list_rules(pid, seq, &dest->q);
1183 		mutex_unlock(&audit_filter_mutex);
1184 
1185 		tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1186 		if (IS_ERR(tsk)) {
1187 			skb_queue_purge(&dest->q);
1188 			kfree(dest);
1189 			err = PTR_ERR(tsk);
1190 		}
1191 		break;
1192 	case AUDIT_ADD:
1193 	case AUDIT_ADD_RULE:
1194 		if (type == AUDIT_ADD)
1195 			entry = audit_rule_to_entry(data);
1196 		else
1197 			entry = audit_data_to_entry(data, datasz);
1198 		if (IS_ERR(entry))
1199 			return PTR_ERR(entry);
1200 
1201 		err = audit_add_rule(entry);
1202 		audit_log_rule_change(loginuid, sessionid, sid, "add rule",
1203 				      &entry->rule, !err);
1204 
1205 		if (err)
1206 			audit_free_rule(entry);
1207 		break;
1208 	case AUDIT_DEL:
1209 	case AUDIT_DEL_RULE:
1210 		if (type == AUDIT_DEL)
1211 			entry = audit_rule_to_entry(data);
1212 		else
1213 			entry = audit_data_to_entry(data, datasz);
1214 		if (IS_ERR(entry))
1215 			return PTR_ERR(entry);
1216 
1217 		err = audit_del_rule(entry);
1218 		audit_log_rule_change(loginuid, sessionid, sid, "remove rule",
1219 				      &entry->rule, !err);
1220 
1221 		audit_free_rule(entry);
1222 		break;
1223 	default:
1224 		return -EINVAL;
1225 	}
1226 
1227 	return err;
1228 }
1229 
1230 int audit_comparator(u32 left, u32 op, u32 right)
1231 {
1232 	switch (op) {
1233 	case Audit_equal:
1234 		return (left == right);
1235 	case Audit_not_equal:
1236 		return (left != right);
1237 	case Audit_lt:
1238 		return (left < right);
1239 	case Audit_le:
1240 		return (left <= right);
1241 	case Audit_gt:
1242 		return (left > right);
1243 	case Audit_ge:
1244 		return (left >= right);
1245 	case Audit_bitmask:
1246 		return (left & right);
1247 	case Audit_bittest:
1248 		return ((left & right) == right);
1249 	default:
1250 		BUG();
1251 		return 0;
1252 	}
1253 }
1254 
1255 int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
1256 {
1257 	switch (op) {
1258 	case Audit_equal:
1259 		return uid_eq(left, right);
1260 	case Audit_not_equal:
1261 		return !uid_eq(left, right);
1262 	case Audit_lt:
1263 		return uid_lt(left, right);
1264 	case Audit_le:
1265 		return uid_lte(left, right);
1266 	case Audit_gt:
1267 		return uid_gt(left, right);
1268 	case Audit_ge:
1269 		return uid_gte(left, right);
1270 	case Audit_bitmask:
1271 	case Audit_bittest:
1272 	default:
1273 		BUG();
1274 		return 0;
1275 	}
1276 }
1277 
1278 int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
1279 {
1280 	switch (op) {
1281 	case Audit_equal:
1282 		return gid_eq(left, right);
1283 	case Audit_not_equal:
1284 		return !gid_eq(left, right);
1285 	case Audit_lt:
1286 		return gid_lt(left, right);
1287 	case Audit_le:
1288 		return gid_lte(left, right);
1289 	case Audit_gt:
1290 		return gid_gt(left, right);
1291 	case Audit_ge:
1292 		return gid_gte(left, right);
1293 	case Audit_bitmask:
1294 	case Audit_bittest:
1295 	default:
1296 		BUG();
1297 		return 0;
1298 	}
1299 }
1300 
1301 /**
1302  * parent_len - find the length of the parent portion of a pathname
1303  * @path: pathname of which to determine length
1304  */
1305 int parent_len(const char *path)
1306 {
1307 	int plen;
1308 	const char *p;
1309 
1310 	plen = strlen(path);
1311 
1312 	if (plen == 0)
1313 		return plen;
1314 
1315 	/* disregard trailing slashes */
1316 	p = path + plen - 1;
1317 	while ((*p == '/') && (p > path))
1318 		p--;
1319 
1320 	/* walk backward until we find the next slash or hit beginning */
1321 	while ((*p != '/') && (p > path))
1322 		p--;
1323 
1324 	/* did we find a slash? Then increment to include it in path */
1325 	if (*p == '/')
1326 		p++;
1327 
1328 	return p - path;
1329 }
1330 
1331 /**
1332  * audit_compare_dname_path - compare given dentry name with last component in
1333  * 			      given path. Return of 0 indicates a match.
1334  * @dname:	dentry name that we're comparing
1335  * @path:	full pathname that we're comparing
1336  * @parentlen:	length of the parent if known. Passing in AUDIT_NAME_FULL
1337  * 		here indicates that we must compute this value.
1338  */
1339 int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
1340 {
1341 	int dlen, pathlen;
1342 	const char *p;
1343 
1344 	dlen = strlen(dname);
1345 	pathlen = strlen(path);
1346 	if (pathlen < dlen)
1347 		return 1;
1348 
1349 	parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
1350 	if (pathlen - parentlen != dlen)
1351 		return 1;
1352 
1353 	p = path + parentlen;
1354 
1355 	return strncmp(p, dname, dlen);
1356 }
1357 
1358 static int audit_filter_user_rules(struct audit_krule *rule,
1359 				   enum audit_state *state)
1360 {
1361 	int i;
1362 
1363 	for (i = 0; i < rule->field_count; i++) {
1364 		struct audit_field *f = &rule->fields[i];
1365 		int result = 0;
1366 		u32 sid;
1367 
1368 		switch (f->type) {
1369 		case AUDIT_PID:
1370 			result = audit_comparator(task_pid_vnr(current), f->op, f->val);
1371 			break;
1372 		case AUDIT_UID:
1373 			result = audit_uid_comparator(current_uid(), f->op, f->uid);
1374 			break;
1375 		case AUDIT_GID:
1376 			result = audit_gid_comparator(current_gid(), f->op, f->gid);
1377 			break;
1378 		case AUDIT_LOGINUID:
1379 			result = audit_uid_comparator(audit_get_loginuid(current),
1380 						  f->op, f->uid);
1381 			break;
1382 		case AUDIT_SUBJ_USER:
1383 		case AUDIT_SUBJ_ROLE:
1384 		case AUDIT_SUBJ_TYPE:
1385 		case AUDIT_SUBJ_SEN:
1386 		case AUDIT_SUBJ_CLR:
1387 			if (f->lsm_rule) {
1388 				security_task_getsecid(current, &sid);
1389 				result = security_audit_rule_match(sid,
1390 								   f->type,
1391 								   f->op,
1392 								   f->lsm_rule,
1393 								   NULL);
1394 			}
1395 			break;
1396 		}
1397 
1398 		if (!result)
1399 			return 0;
1400 	}
1401 	switch (rule->action) {
1402 	case AUDIT_NEVER:    *state = AUDIT_DISABLED;	    break;
1403 	case AUDIT_ALWAYS:   *state = AUDIT_RECORD_CONTEXT; break;
1404 	}
1405 	return 1;
1406 }
1407 
1408 int audit_filter_user(void)
1409 {
1410 	enum audit_state state = AUDIT_DISABLED;
1411 	struct audit_entry *e;
1412 	int ret = 1;
1413 
1414 	rcu_read_lock();
1415 	list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1416 		if (audit_filter_user_rules(&e->rule, &state)) {
1417 			if (state == AUDIT_DISABLED)
1418 				ret = 0;
1419 			break;
1420 		}
1421 	}
1422 	rcu_read_unlock();
1423 
1424 	return ret; /* Audit by default */
1425 }
1426 
1427 int audit_filter_type(int type)
1428 {
1429 	struct audit_entry *e;
1430 	int result = 0;
1431 
1432 	rcu_read_lock();
1433 	if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1434 		goto unlock_and_return;
1435 
1436 	list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1437 				list) {
1438 		int i;
1439 		for (i = 0; i < e->rule.field_count; i++) {
1440 			struct audit_field *f = &e->rule.fields[i];
1441 			if (f->type == AUDIT_MSGTYPE) {
1442 				result = audit_comparator(type, f->op, f->val);
1443 				if (!result)
1444 					break;
1445 			}
1446 		}
1447 		if (result)
1448 			goto unlock_and_return;
1449 	}
1450 unlock_and_return:
1451 	rcu_read_unlock();
1452 	return result;
1453 }
1454 
1455 static int update_lsm_rule(struct audit_krule *r)
1456 {
1457 	struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1458 	struct audit_entry *nentry;
1459 	int err = 0;
1460 
1461 	if (!security_audit_rule_known(r))
1462 		return 0;
1463 
1464 	nentry = audit_dupe_rule(r);
1465 	if (IS_ERR(nentry)) {
1466 		/* save the first error encountered for the
1467 		 * return value */
1468 		err = PTR_ERR(nentry);
1469 		audit_panic("error updating LSM filters");
1470 		if (r->watch)
1471 			list_del(&r->rlist);
1472 		list_del_rcu(&entry->list);
1473 		list_del(&r->list);
1474 	} else {
1475 		if (r->watch || r->tree)
1476 			list_replace_init(&r->rlist, &nentry->rule.rlist);
1477 		list_replace_rcu(&entry->list, &nentry->list);
1478 		list_replace(&r->list, &nentry->rule.list);
1479 	}
1480 	call_rcu(&entry->rcu, audit_free_rule_rcu);
1481 
1482 	return err;
1483 }
1484 
1485 /* This function will re-initialize the lsm_rule field of all applicable rules.
1486  * It will traverse the filter lists serarching for rules that contain LSM
1487  * specific filter fields.  When such a rule is found, it is copied, the
1488  * LSM field is re-initialized, and the old rule is replaced with the
1489  * updated rule. */
1490 int audit_update_lsm_rules(void)
1491 {
1492 	struct audit_krule *r, *n;
1493 	int i, err = 0;
1494 
1495 	/* audit_filter_mutex synchronizes the writers */
1496 	mutex_lock(&audit_filter_mutex);
1497 
1498 	for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1499 		list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1500 			int res = update_lsm_rule(r);
1501 			if (!err)
1502 				err = res;
1503 		}
1504 	}
1505 	mutex_unlock(&audit_filter_mutex);
1506 
1507 	return err;
1508 }
1509