xref: /openbmc/linux/kernel/auditfilter.c (revision c21b37f6)
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/inotify.h>
31 #include <linux/selinux.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  * 		selinux 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 /*
48  * Reference counting:
49  *
50  * audit_parent: lifetime is from audit_init_parent() to receipt of an IN_IGNORED
51  * 	event.  Each audit_watch holds a reference to its associated parent.
52  *
53  * audit_watch: if added to lists, lifetime is from audit_init_watch() to
54  * 	audit_remove_watch().  Additionally, an audit_watch may exist
55  * 	temporarily to assist in searching existing filter data.  Each
56  * 	audit_krule holds a reference to its associated watch.
57  */
58 
59 struct audit_parent {
60 	struct list_head	ilist;	/* entry in inotify registration list */
61 	struct list_head	watches; /* associated watches */
62 	struct inotify_watch	wdata;	/* inotify watch data */
63 	unsigned		flags;	/* status flags */
64 };
65 
66 /*
67  * audit_parent status flags:
68  *
69  * AUDIT_PARENT_INVALID - set anytime rules/watches are auto-removed due to
70  * a filesystem event to ensure we're adding audit watches to a valid parent.
71  * Technically not needed for IN_DELETE_SELF or IN_UNMOUNT events, as we cannot
72  * receive them while we have nameidata, but must be used for IN_MOVE_SELF which
73  * we can receive while holding nameidata.
74  */
75 #define AUDIT_PARENT_INVALID	0x001
76 
77 /* Audit filter lists, defined in <linux/audit.h> */
78 struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
79 	LIST_HEAD_INIT(audit_filter_list[0]),
80 	LIST_HEAD_INIT(audit_filter_list[1]),
81 	LIST_HEAD_INIT(audit_filter_list[2]),
82 	LIST_HEAD_INIT(audit_filter_list[3]),
83 	LIST_HEAD_INIT(audit_filter_list[4]),
84 	LIST_HEAD_INIT(audit_filter_list[5]),
85 #if AUDIT_NR_FILTERS != 6
86 #error Fix audit_filter_list initialiser
87 #endif
88 };
89 
90 static DEFINE_MUTEX(audit_filter_mutex);
91 
92 /* Inotify handle */
93 extern struct inotify_handle *audit_ih;
94 
95 /* Inotify events we care about. */
96 #define AUDIT_IN_WATCH IN_MOVE|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF
97 
98 void audit_free_parent(struct inotify_watch *i_watch)
99 {
100 	struct audit_parent *parent;
101 
102 	parent = container_of(i_watch, struct audit_parent, wdata);
103 	WARN_ON(!list_empty(&parent->watches));
104 	kfree(parent);
105 }
106 
107 static inline void audit_get_watch(struct audit_watch *watch)
108 {
109 	atomic_inc(&watch->count);
110 }
111 
112 static void audit_put_watch(struct audit_watch *watch)
113 {
114 	if (atomic_dec_and_test(&watch->count)) {
115 		WARN_ON(watch->parent);
116 		WARN_ON(!list_empty(&watch->rules));
117 		kfree(watch->path);
118 		kfree(watch);
119 	}
120 }
121 
122 static void audit_remove_watch(struct audit_watch *watch)
123 {
124 	list_del(&watch->wlist);
125 	put_inotify_watch(&watch->parent->wdata);
126 	watch->parent = NULL;
127 	audit_put_watch(watch); /* match initial get */
128 }
129 
130 static inline void audit_free_rule(struct audit_entry *e)
131 {
132 	int i;
133 
134 	/* some rules don't have associated watches */
135 	if (e->rule.watch)
136 		audit_put_watch(e->rule.watch);
137 	if (e->rule.fields)
138 		for (i = 0; i < e->rule.field_count; i++) {
139 			struct audit_field *f = &e->rule.fields[i];
140 			kfree(f->se_str);
141 			selinux_audit_rule_free(f->se_rule);
142 		}
143 	kfree(e->rule.fields);
144 	kfree(e->rule.filterkey);
145 	kfree(e);
146 }
147 
148 static inline void audit_free_rule_rcu(struct rcu_head *head)
149 {
150 	struct audit_entry *e = container_of(head, struct audit_entry, rcu);
151 	audit_free_rule(e);
152 }
153 
154 /* Initialize a parent watch entry. */
155 static struct audit_parent *audit_init_parent(struct nameidata *ndp)
156 {
157 	struct audit_parent *parent;
158 	s32 wd;
159 
160 	parent = kzalloc(sizeof(*parent), GFP_KERNEL);
161 	if (unlikely(!parent))
162 		return ERR_PTR(-ENOMEM);
163 
164 	INIT_LIST_HEAD(&parent->watches);
165 	parent->flags = 0;
166 
167 	inotify_init_watch(&parent->wdata);
168 	/* grab a ref so inotify watch hangs around until we take audit_filter_mutex */
169 	get_inotify_watch(&parent->wdata);
170 	wd = inotify_add_watch(audit_ih, &parent->wdata, ndp->dentry->d_inode,
171 			       AUDIT_IN_WATCH);
172 	if (wd < 0) {
173 		audit_free_parent(&parent->wdata);
174 		return ERR_PTR(wd);
175 	}
176 
177 	return parent;
178 }
179 
180 /* Initialize a watch entry. */
181 static struct audit_watch *audit_init_watch(char *path)
182 {
183 	struct audit_watch *watch;
184 
185 	watch = kzalloc(sizeof(*watch), GFP_KERNEL);
186 	if (unlikely(!watch))
187 		return ERR_PTR(-ENOMEM);
188 
189 	INIT_LIST_HEAD(&watch->rules);
190 	atomic_set(&watch->count, 1);
191 	watch->path = path;
192 	watch->dev = (dev_t)-1;
193 	watch->ino = (unsigned long)-1;
194 
195 	return watch;
196 }
197 
198 /* Initialize an audit filterlist entry. */
199 static inline struct audit_entry *audit_init_entry(u32 field_count)
200 {
201 	struct audit_entry *entry;
202 	struct audit_field *fields;
203 
204 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
205 	if (unlikely(!entry))
206 		return NULL;
207 
208 	fields = kzalloc(sizeof(*fields) * field_count, GFP_KERNEL);
209 	if (unlikely(!fields)) {
210 		kfree(entry);
211 		return NULL;
212 	}
213 	entry->rule.fields = fields;
214 
215 	return entry;
216 }
217 
218 /* Unpack a filter field's string representation from user-space
219  * buffer. */
220 static char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
221 {
222 	char *str;
223 
224 	if (!*bufp || (len == 0) || (len > *remain))
225 		return ERR_PTR(-EINVAL);
226 
227 	/* Of the currently implemented string fields, PATH_MAX
228 	 * defines the longest valid length.
229 	 */
230 	if (len > PATH_MAX)
231 		return ERR_PTR(-ENAMETOOLONG);
232 
233 	str = kmalloc(len + 1, GFP_KERNEL);
234 	if (unlikely(!str))
235 		return ERR_PTR(-ENOMEM);
236 
237 	memcpy(str, *bufp, len);
238 	str[len] = 0;
239 	*bufp += len;
240 	*remain -= len;
241 
242 	return str;
243 }
244 
245 /* Translate an inode field to kernel respresentation. */
246 static inline int audit_to_inode(struct audit_krule *krule,
247 				 struct audit_field *f)
248 {
249 	if (krule->listnr != AUDIT_FILTER_EXIT ||
250 	    krule->watch || krule->inode_f)
251 		return -EINVAL;
252 
253 	krule->inode_f = f;
254 	return 0;
255 }
256 
257 /* Translate a watch string to kernel respresentation. */
258 static int audit_to_watch(struct audit_krule *krule, char *path, int len,
259 			  u32 op)
260 {
261 	struct audit_watch *watch;
262 
263 	if (!audit_ih)
264 		return -EOPNOTSUPP;
265 
266 	if (path[0] != '/' || path[len-1] == '/' ||
267 	    krule->listnr != AUDIT_FILTER_EXIT ||
268 	    op & ~AUDIT_EQUAL ||
269 	    krule->inode_f || krule->watch) /* 1 inode # per rule, for hash */
270 		return -EINVAL;
271 
272 	watch = audit_init_watch(path);
273 	if (unlikely(IS_ERR(watch)))
274 		return PTR_ERR(watch);
275 
276 	audit_get_watch(watch);
277 	krule->watch = watch;
278 
279 	return 0;
280 }
281 
282 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
283 
284 int __init audit_register_class(int class, unsigned *list)
285 {
286 	__u32 *p = kzalloc(AUDIT_BITMASK_SIZE * sizeof(__u32), GFP_KERNEL);
287 	if (!p)
288 		return -ENOMEM;
289 	while (*list != ~0U) {
290 		unsigned n = *list++;
291 		if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
292 			kfree(p);
293 			return -EINVAL;
294 		}
295 		p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
296 	}
297 	if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
298 		kfree(p);
299 		return -EINVAL;
300 	}
301 	classes[class] = p;
302 	return 0;
303 }
304 
305 int audit_match_class(int class, unsigned syscall)
306 {
307 	if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
308 		return 0;
309 	if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
310 		return 0;
311 	return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
312 }
313 
314 #ifdef CONFIG_AUDITSYSCALL
315 static inline int audit_match_class_bits(int class, u32 *mask)
316 {
317 	int i;
318 
319 	if (classes[class]) {
320 		for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
321 			if (mask[i] & classes[class][i])
322 				return 0;
323 	}
324 	return 1;
325 }
326 
327 static int audit_match_signal(struct audit_entry *entry)
328 {
329 	struct audit_field *arch = entry->rule.arch_f;
330 
331 	if (!arch) {
332 		/* When arch is unspecified, we must check both masks on biarch
333 		 * as syscall number alone is ambiguous. */
334 		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
335 					       entry->rule.mask) &&
336 			audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
337 					       entry->rule.mask));
338 	}
339 
340 	switch(audit_classify_arch(arch->val)) {
341 	case 0: /* native */
342 		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
343 					       entry->rule.mask));
344 	case 1: /* 32bit on biarch */
345 		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
346 					       entry->rule.mask));
347 	default:
348 		return 1;
349 	}
350 }
351 #endif
352 
353 /* Common user-space to kernel rule translation. */
354 static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule)
355 {
356 	unsigned listnr;
357 	struct audit_entry *entry;
358 	int i, err;
359 
360 	err = -EINVAL;
361 	listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
362 	switch(listnr) {
363 	default:
364 		goto exit_err;
365 	case AUDIT_FILTER_USER:
366 	case AUDIT_FILTER_TYPE:
367 #ifdef CONFIG_AUDITSYSCALL
368 	case AUDIT_FILTER_ENTRY:
369 	case AUDIT_FILTER_EXIT:
370 	case AUDIT_FILTER_TASK:
371 #endif
372 		;
373 	}
374 	if (unlikely(rule->action == AUDIT_POSSIBLE)) {
375 		printk(KERN_ERR "AUDIT_POSSIBLE is deprecated\n");
376 		goto exit_err;
377 	}
378 	if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
379 		goto exit_err;
380 	if (rule->field_count > AUDIT_MAX_FIELDS)
381 		goto exit_err;
382 
383 	err = -ENOMEM;
384 	entry = audit_init_entry(rule->field_count);
385 	if (!entry)
386 		goto exit_err;
387 
388 	entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
389 	entry->rule.listnr = listnr;
390 	entry->rule.action = rule->action;
391 	entry->rule.field_count = rule->field_count;
392 
393 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
394 		entry->rule.mask[i] = rule->mask[i];
395 
396 	for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
397 		int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
398 		__u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
399 		__u32 *class;
400 
401 		if (!(*p & AUDIT_BIT(bit)))
402 			continue;
403 		*p &= ~AUDIT_BIT(bit);
404 		class = classes[i];
405 		if (class) {
406 			int j;
407 			for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
408 				entry->rule.mask[j] |= class[j];
409 		}
410 	}
411 
412 	return entry;
413 
414 exit_err:
415 	return ERR_PTR(err);
416 }
417 
418 /* Translate struct audit_rule to kernel's rule respresentation.
419  * Exists for backward compatibility with userspace. */
420 static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
421 {
422 	struct audit_entry *entry;
423 	struct audit_field *f;
424 	int err = 0;
425 	int i;
426 
427 	entry = audit_to_entry_common(rule);
428 	if (IS_ERR(entry))
429 		goto exit_nofree;
430 
431 	for (i = 0; i < rule->field_count; i++) {
432 		struct audit_field *f = &entry->rule.fields[i];
433 
434 		f->op = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS);
435 		f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS);
436 		f->val = rule->values[i];
437 
438 		err = -EINVAL;
439 		switch(f->type) {
440 		default:
441 			goto exit_free;
442 		case AUDIT_PID:
443 		case AUDIT_UID:
444 		case AUDIT_EUID:
445 		case AUDIT_SUID:
446 		case AUDIT_FSUID:
447 		case AUDIT_GID:
448 		case AUDIT_EGID:
449 		case AUDIT_SGID:
450 		case AUDIT_FSGID:
451 		case AUDIT_LOGINUID:
452 		case AUDIT_PERS:
453 		case AUDIT_MSGTYPE:
454 		case AUDIT_PPID:
455 		case AUDIT_DEVMAJOR:
456 		case AUDIT_DEVMINOR:
457 		case AUDIT_EXIT:
458 		case AUDIT_SUCCESS:
459 			/* bit ops are only useful on syscall args */
460 			if (f->op == AUDIT_BIT_MASK ||
461 						f->op == AUDIT_BIT_TEST) {
462 				err = -EINVAL;
463 				goto exit_free;
464 			}
465 			break;
466 		case AUDIT_ARG0:
467 		case AUDIT_ARG1:
468 		case AUDIT_ARG2:
469 		case AUDIT_ARG3:
470 			break;
471 		/* arch is only allowed to be = or != */
472 		case AUDIT_ARCH:
473 			if ((f->op != AUDIT_NOT_EQUAL) && (f->op != AUDIT_EQUAL)
474 					&& (f->op != AUDIT_NEGATE) && (f->op)) {
475 				err = -EINVAL;
476 				goto exit_free;
477 			}
478 			entry->rule.arch_f = f;
479 			break;
480 		case AUDIT_PERM:
481 			if (f->val & ~15)
482 				goto exit_free;
483 			break;
484 		case AUDIT_INODE:
485 			err = audit_to_inode(&entry->rule, f);
486 			if (err)
487 				goto exit_free;
488 			break;
489 		}
490 
491 		entry->rule.vers_ops = (f->op & AUDIT_OPERATORS) ? 2 : 1;
492 
493 		/* Support for legacy operators where
494 		 * AUDIT_NEGATE bit signifies != and otherwise assumes == */
495 		if (f->op & AUDIT_NEGATE)
496 			f->op = AUDIT_NOT_EQUAL;
497 		else if (!f->op)
498 			f->op = AUDIT_EQUAL;
499 		else if (f->op == AUDIT_OPERATORS) {
500 			err = -EINVAL;
501 			goto exit_free;
502 		}
503 	}
504 
505 	f = entry->rule.inode_f;
506 	if (f) {
507 		switch(f->op) {
508 		case AUDIT_NOT_EQUAL:
509 			entry->rule.inode_f = NULL;
510 		case AUDIT_EQUAL:
511 			break;
512 		default:
513 			err = -EINVAL;
514 			goto exit_free;
515 		}
516 	}
517 
518 exit_nofree:
519 	return entry;
520 
521 exit_free:
522 	audit_free_rule(entry);
523 	return ERR_PTR(err);
524 }
525 
526 /* Translate struct audit_rule_data to kernel's rule respresentation. */
527 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
528 					       size_t datasz)
529 {
530 	int err = 0;
531 	struct audit_entry *entry;
532 	struct audit_field *f;
533 	void *bufp;
534 	size_t remain = datasz - sizeof(struct audit_rule_data);
535 	int i;
536 	char *str;
537 
538 	entry = audit_to_entry_common((struct audit_rule *)data);
539 	if (IS_ERR(entry))
540 		goto exit_nofree;
541 
542 	bufp = data->buf;
543 	entry->rule.vers_ops = 2;
544 	for (i = 0; i < data->field_count; i++) {
545 		struct audit_field *f = &entry->rule.fields[i];
546 
547 		err = -EINVAL;
548 		if (!(data->fieldflags[i] & AUDIT_OPERATORS) ||
549 		    data->fieldflags[i] & ~AUDIT_OPERATORS)
550 			goto exit_free;
551 
552 		f->op = data->fieldflags[i] & AUDIT_OPERATORS;
553 		f->type = data->fields[i];
554 		f->val = data->values[i];
555 		f->se_str = NULL;
556 		f->se_rule = NULL;
557 		switch(f->type) {
558 		case AUDIT_PID:
559 		case AUDIT_UID:
560 		case AUDIT_EUID:
561 		case AUDIT_SUID:
562 		case AUDIT_FSUID:
563 		case AUDIT_GID:
564 		case AUDIT_EGID:
565 		case AUDIT_SGID:
566 		case AUDIT_FSGID:
567 		case AUDIT_LOGINUID:
568 		case AUDIT_PERS:
569 		case AUDIT_MSGTYPE:
570 		case AUDIT_PPID:
571 		case AUDIT_DEVMAJOR:
572 		case AUDIT_DEVMINOR:
573 		case AUDIT_EXIT:
574 		case AUDIT_SUCCESS:
575 		case AUDIT_ARG0:
576 		case AUDIT_ARG1:
577 		case AUDIT_ARG2:
578 		case AUDIT_ARG3:
579 			break;
580 		case AUDIT_ARCH:
581 			entry->rule.arch_f = f;
582 			break;
583 		case AUDIT_SUBJ_USER:
584 		case AUDIT_SUBJ_ROLE:
585 		case AUDIT_SUBJ_TYPE:
586 		case AUDIT_SUBJ_SEN:
587 		case AUDIT_SUBJ_CLR:
588 		case AUDIT_OBJ_USER:
589 		case AUDIT_OBJ_ROLE:
590 		case AUDIT_OBJ_TYPE:
591 		case AUDIT_OBJ_LEV_LOW:
592 		case AUDIT_OBJ_LEV_HIGH:
593 			str = audit_unpack_string(&bufp, &remain, f->val);
594 			if (IS_ERR(str))
595 				goto exit_free;
596 			entry->rule.buflen += f->val;
597 
598 			err = selinux_audit_rule_init(f->type, f->op, str,
599 						      &f->se_rule);
600 			/* Keep currently invalid fields around in case they
601 			 * become valid after a policy reload. */
602 			if (err == -EINVAL) {
603 				printk(KERN_WARNING "audit rule for selinux "
604 				       "\'%s\' is invalid\n",  str);
605 				err = 0;
606 			}
607 			if (err) {
608 				kfree(str);
609 				goto exit_free;
610 			} else
611 				f->se_str = str;
612 			break;
613 		case AUDIT_WATCH:
614 			str = audit_unpack_string(&bufp, &remain, f->val);
615 			if (IS_ERR(str))
616 				goto exit_free;
617 			entry->rule.buflen += f->val;
618 
619 			err = audit_to_watch(&entry->rule, str, f->val, f->op);
620 			if (err) {
621 				kfree(str);
622 				goto exit_free;
623 			}
624 			break;
625 		case AUDIT_INODE:
626 			err = audit_to_inode(&entry->rule, f);
627 			if (err)
628 				goto exit_free;
629 			break;
630 		case AUDIT_FILTERKEY:
631 			err = -EINVAL;
632 			if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
633 				goto exit_free;
634 			str = audit_unpack_string(&bufp, &remain, f->val);
635 			if (IS_ERR(str))
636 				goto exit_free;
637 			entry->rule.buflen += f->val;
638 			entry->rule.filterkey = str;
639 			break;
640 		case AUDIT_PERM:
641 			if (f->val & ~15)
642 				goto exit_free;
643 			break;
644 		default:
645 			goto exit_free;
646 		}
647 	}
648 
649 	f = entry->rule.inode_f;
650 	if (f) {
651 		switch(f->op) {
652 		case AUDIT_NOT_EQUAL:
653 			entry->rule.inode_f = NULL;
654 		case AUDIT_EQUAL:
655 			break;
656 		default:
657 			err = -EINVAL;
658 			goto exit_free;
659 		}
660 	}
661 
662 exit_nofree:
663 	return entry;
664 
665 exit_free:
666 	audit_free_rule(entry);
667 	return ERR_PTR(err);
668 }
669 
670 /* Pack a filter field's string representation into data block. */
671 static inline size_t audit_pack_string(void **bufp, char *str)
672 {
673 	size_t len = strlen(str);
674 
675 	memcpy(*bufp, str, len);
676 	*bufp += len;
677 
678 	return len;
679 }
680 
681 /* Translate kernel rule respresentation to struct audit_rule.
682  * Exists for backward compatibility with userspace. */
683 static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
684 {
685 	struct audit_rule *rule;
686 	int i;
687 
688 	rule = kzalloc(sizeof(*rule), GFP_KERNEL);
689 	if (unlikely(!rule))
690 		return NULL;
691 
692 	rule->flags = krule->flags | krule->listnr;
693 	rule->action = krule->action;
694 	rule->field_count = krule->field_count;
695 	for (i = 0; i < rule->field_count; i++) {
696 		rule->values[i] = krule->fields[i].val;
697 		rule->fields[i] = krule->fields[i].type;
698 
699 		if (krule->vers_ops == 1) {
700 			if (krule->fields[i].op & AUDIT_NOT_EQUAL)
701 				rule->fields[i] |= AUDIT_NEGATE;
702 		} else {
703 			rule->fields[i] |= krule->fields[i].op;
704 		}
705 	}
706 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
707 
708 	return rule;
709 }
710 
711 /* Translate kernel rule respresentation to struct audit_rule_data. */
712 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
713 {
714 	struct audit_rule_data *data;
715 	void *bufp;
716 	int i;
717 
718 	data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
719 	if (unlikely(!data))
720 		return NULL;
721 	memset(data, 0, sizeof(*data));
722 
723 	data->flags = krule->flags | krule->listnr;
724 	data->action = krule->action;
725 	data->field_count = krule->field_count;
726 	bufp = data->buf;
727 	for (i = 0; i < data->field_count; i++) {
728 		struct audit_field *f = &krule->fields[i];
729 
730 		data->fields[i] = f->type;
731 		data->fieldflags[i] = f->op;
732 		switch(f->type) {
733 		case AUDIT_SUBJ_USER:
734 		case AUDIT_SUBJ_ROLE:
735 		case AUDIT_SUBJ_TYPE:
736 		case AUDIT_SUBJ_SEN:
737 		case AUDIT_SUBJ_CLR:
738 		case AUDIT_OBJ_USER:
739 		case AUDIT_OBJ_ROLE:
740 		case AUDIT_OBJ_TYPE:
741 		case AUDIT_OBJ_LEV_LOW:
742 		case AUDIT_OBJ_LEV_HIGH:
743 			data->buflen += data->values[i] =
744 				audit_pack_string(&bufp, f->se_str);
745 			break;
746 		case AUDIT_WATCH:
747 			data->buflen += data->values[i] =
748 				audit_pack_string(&bufp, krule->watch->path);
749 			break;
750 		case AUDIT_FILTERKEY:
751 			data->buflen += data->values[i] =
752 				audit_pack_string(&bufp, krule->filterkey);
753 			break;
754 		default:
755 			data->values[i] = f->val;
756 		}
757 	}
758 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
759 
760 	return data;
761 }
762 
763 /* Compare two rules in kernel format.  Considered success if rules
764  * don't match. */
765 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
766 {
767 	int i;
768 
769 	if (a->flags != b->flags ||
770 	    a->listnr != b->listnr ||
771 	    a->action != b->action ||
772 	    a->field_count != b->field_count)
773 		return 1;
774 
775 	for (i = 0; i < a->field_count; i++) {
776 		if (a->fields[i].type != b->fields[i].type ||
777 		    a->fields[i].op != b->fields[i].op)
778 			return 1;
779 
780 		switch(a->fields[i].type) {
781 		case AUDIT_SUBJ_USER:
782 		case AUDIT_SUBJ_ROLE:
783 		case AUDIT_SUBJ_TYPE:
784 		case AUDIT_SUBJ_SEN:
785 		case AUDIT_SUBJ_CLR:
786 		case AUDIT_OBJ_USER:
787 		case AUDIT_OBJ_ROLE:
788 		case AUDIT_OBJ_TYPE:
789 		case AUDIT_OBJ_LEV_LOW:
790 		case AUDIT_OBJ_LEV_HIGH:
791 			if (strcmp(a->fields[i].se_str, b->fields[i].se_str))
792 				return 1;
793 			break;
794 		case AUDIT_WATCH:
795 			if (strcmp(a->watch->path, b->watch->path))
796 				return 1;
797 			break;
798 		case AUDIT_FILTERKEY:
799 			/* both filterkeys exist based on above type compare */
800 			if (strcmp(a->filterkey, b->filterkey))
801 				return 1;
802 			break;
803 		default:
804 			if (a->fields[i].val != b->fields[i].val)
805 				return 1;
806 		}
807 	}
808 
809 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
810 		if (a->mask[i] != b->mask[i])
811 			return 1;
812 
813 	return 0;
814 }
815 
816 /* Duplicate the given audit watch.  The new watch's rules list is initialized
817  * to an empty list and wlist is undefined. */
818 static struct audit_watch *audit_dupe_watch(struct audit_watch *old)
819 {
820 	char *path;
821 	struct audit_watch *new;
822 
823 	path = kstrdup(old->path, GFP_KERNEL);
824 	if (unlikely(!path))
825 		return ERR_PTR(-ENOMEM);
826 
827 	new = audit_init_watch(path);
828 	if (unlikely(IS_ERR(new))) {
829 		kfree(path);
830 		goto out;
831 	}
832 
833 	new->dev = old->dev;
834 	new->ino = old->ino;
835 	get_inotify_watch(&old->parent->wdata);
836 	new->parent = old->parent;
837 
838 out:
839 	return new;
840 }
841 
842 /* Duplicate selinux field information.  The se_rule is opaque, so must be
843  * re-initialized. */
844 static inline int audit_dupe_selinux_field(struct audit_field *df,
845 					   struct audit_field *sf)
846 {
847 	int ret = 0;
848 	char *se_str;
849 
850 	/* our own copy of se_str */
851 	se_str = kstrdup(sf->se_str, GFP_KERNEL);
852 	if (unlikely(!se_str))
853 		return -ENOMEM;
854 	df->se_str = se_str;
855 
856 	/* our own (refreshed) copy of se_rule */
857 	ret = selinux_audit_rule_init(df->type, df->op, df->se_str,
858 				      &df->se_rule);
859 	/* Keep currently invalid fields around in case they
860 	 * become valid after a policy reload. */
861 	if (ret == -EINVAL) {
862 		printk(KERN_WARNING "audit rule for selinux \'%s\' is "
863 		       "invalid\n", df->se_str);
864 		ret = 0;
865 	}
866 
867 	return ret;
868 }
869 
870 /* Duplicate an audit rule.  This will be a deep copy with the exception
871  * of the watch - that pointer is carried over.  The selinux specific fields
872  * will be updated in the copy.  The point is to be able to replace the old
873  * rule with the new rule in the filterlist, then free the old rule.
874  * The rlist element is undefined; list manipulations are handled apart from
875  * the initial copy. */
876 static struct audit_entry *audit_dupe_rule(struct audit_krule *old,
877 					   struct audit_watch *watch)
878 {
879 	u32 fcount = old->field_count;
880 	struct audit_entry *entry;
881 	struct audit_krule *new;
882 	char *fk;
883 	int i, err = 0;
884 
885 	entry = audit_init_entry(fcount);
886 	if (unlikely(!entry))
887 		return ERR_PTR(-ENOMEM);
888 
889 	new = &entry->rule;
890 	new->vers_ops = old->vers_ops;
891 	new->flags = old->flags;
892 	new->listnr = old->listnr;
893 	new->action = old->action;
894 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
895 		new->mask[i] = old->mask[i];
896 	new->buflen = old->buflen;
897 	new->inode_f = old->inode_f;
898 	new->watch = NULL;
899 	new->field_count = old->field_count;
900 	memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
901 
902 	/* deep copy this information, updating the se_rule fields, because
903 	 * the originals will all be freed when the old rule is freed. */
904 	for (i = 0; i < fcount; i++) {
905 		switch (new->fields[i].type) {
906 		case AUDIT_SUBJ_USER:
907 		case AUDIT_SUBJ_ROLE:
908 		case AUDIT_SUBJ_TYPE:
909 		case AUDIT_SUBJ_SEN:
910 		case AUDIT_SUBJ_CLR:
911 		case AUDIT_OBJ_USER:
912 		case AUDIT_OBJ_ROLE:
913 		case AUDIT_OBJ_TYPE:
914 		case AUDIT_OBJ_LEV_LOW:
915 		case AUDIT_OBJ_LEV_HIGH:
916 			err = audit_dupe_selinux_field(&new->fields[i],
917 						       &old->fields[i]);
918 			break;
919 		case AUDIT_FILTERKEY:
920 			fk = kstrdup(old->filterkey, GFP_KERNEL);
921 			if (unlikely(!fk))
922 				err = -ENOMEM;
923 			else
924 				new->filterkey = fk;
925 		}
926 		if (err) {
927 			audit_free_rule(entry);
928 			return ERR_PTR(err);
929 		}
930 	}
931 
932 	if (watch) {
933 		audit_get_watch(watch);
934 		new->watch = watch;
935 	}
936 
937 	return entry;
938 }
939 
940 /* Update inode info in audit rules based on filesystem event. */
941 static void audit_update_watch(struct audit_parent *parent,
942 			       const char *dname, dev_t dev,
943 			       unsigned long ino, unsigned invalidating)
944 {
945 	struct audit_watch *owatch, *nwatch, *nextw;
946 	struct audit_krule *r, *nextr;
947 	struct audit_entry *oentry, *nentry;
948 	struct audit_buffer *ab;
949 
950 	mutex_lock(&audit_filter_mutex);
951 	list_for_each_entry_safe(owatch, nextw, &parent->watches, wlist) {
952 		if (audit_compare_dname_path(dname, owatch->path, NULL))
953 			continue;
954 
955 		/* If the update involves invalidating rules, do the inode-based
956 		 * filtering now, so we don't omit records. */
957 		if (invalidating && current->audit_context &&
958 		    audit_filter_inodes(current, current->audit_context) == AUDIT_RECORD_CONTEXT)
959 			audit_set_auditable(current->audit_context);
960 
961 		nwatch = audit_dupe_watch(owatch);
962 		if (unlikely(IS_ERR(nwatch))) {
963 			mutex_unlock(&audit_filter_mutex);
964 			audit_panic("error updating watch, skipping");
965 			return;
966 		}
967 		nwatch->dev = dev;
968 		nwatch->ino = ino;
969 
970 		list_for_each_entry_safe(r, nextr, &owatch->rules, rlist) {
971 
972 			oentry = container_of(r, struct audit_entry, rule);
973 			list_del(&oentry->rule.rlist);
974 			list_del_rcu(&oentry->list);
975 
976 			nentry = audit_dupe_rule(&oentry->rule, nwatch);
977 			if (unlikely(IS_ERR(nentry)))
978 				audit_panic("error updating watch, removing");
979 			else {
980 				int h = audit_hash_ino((u32)ino);
981 				list_add(&nentry->rule.rlist, &nwatch->rules);
982 				list_add_rcu(&nentry->list, &audit_inode_hash[h]);
983 			}
984 
985 			call_rcu(&oentry->rcu, audit_free_rule_rcu);
986 		}
987 
988 		ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
989 		audit_log_format(ab, "op=updated rules specifying path=");
990 		audit_log_untrustedstring(ab, owatch->path);
991 		audit_log_format(ab, " with dev=%u ino=%lu\n", dev, ino);
992 		audit_log_format(ab, " list=%d res=1", r->listnr);
993 		audit_log_end(ab);
994 
995 		audit_remove_watch(owatch);
996 		goto add_watch_to_parent; /* event applies to a single watch */
997 	}
998 	mutex_unlock(&audit_filter_mutex);
999 	return;
1000 
1001 add_watch_to_parent:
1002 	list_add(&nwatch->wlist, &parent->watches);
1003 	mutex_unlock(&audit_filter_mutex);
1004 	return;
1005 }
1006 
1007 /* Remove all watches & rules associated with a parent that is going away. */
1008 static void audit_remove_parent_watches(struct audit_parent *parent)
1009 {
1010 	struct audit_watch *w, *nextw;
1011 	struct audit_krule *r, *nextr;
1012 	struct audit_entry *e;
1013 	struct audit_buffer *ab;
1014 
1015 	mutex_lock(&audit_filter_mutex);
1016 	parent->flags |= AUDIT_PARENT_INVALID;
1017 	list_for_each_entry_safe(w, nextw, &parent->watches, wlist) {
1018 		list_for_each_entry_safe(r, nextr, &w->rules, rlist) {
1019 			e = container_of(r, struct audit_entry, rule);
1020 
1021 			ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1022 			audit_log_format(ab, "op=remove rule path=");
1023 			audit_log_untrustedstring(ab, w->path);
1024 			if (r->filterkey) {
1025 				audit_log_format(ab, " key=");
1026 				audit_log_untrustedstring(ab, r->filterkey);
1027 			} else
1028 				audit_log_format(ab, " key=(null)");
1029 			audit_log_format(ab, " list=%d res=1", r->listnr);
1030 			audit_log_end(ab);
1031 
1032 			list_del(&r->rlist);
1033 			list_del_rcu(&e->list);
1034 			call_rcu(&e->rcu, audit_free_rule_rcu);
1035 		}
1036 		audit_remove_watch(w);
1037 	}
1038 	mutex_unlock(&audit_filter_mutex);
1039 }
1040 
1041 /* Unregister inotify watches for parents on in_list.
1042  * Generates an IN_IGNORED event. */
1043 static void audit_inotify_unregister(struct list_head *in_list)
1044 {
1045 	struct audit_parent *p, *n;
1046 
1047 	list_for_each_entry_safe(p, n, in_list, ilist) {
1048 		list_del(&p->ilist);
1049 		inotify_rm_watch(audit_ih, &p->wdata);
1050 		/* the put matching the get in audit_do_del_rule() */
1051 		put_inotify_watch(&p->wdata);
1052 	}
1053 }
1054 
1055 /* Find an existing audit rule.
1056  * Caller must hold audit_filter_mutex to prevent stale rule data. */
1057 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
1058 					   struct list_head *list)
1059 {
1060 	struct audit_entry *e, *found = NULL;
1061 	int h;
1062 
1063 	if (entry->rule.watch) {
1064 		/* we don't know the inode number, so must walk entire hash */
1065 		for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
1066 			list = &audit_inode_hash[h];
1067 			list_for_each_entry(e, list, list)
1068 				if (!audit_compare_rule(&entry->rule, &e->rule)) {
1069 					found = e;
1070 					goto out;
1071 				}
1072 		}
1073 		goto out;
1074 	}
1075 
1076 	list_for_each_entry(e, list, list)
1077 		if (!audit_compare_rule(&entry->rule, &e->rule)) {
1078 			found = e;
1079 			goto out;
1080 		}
1081 
1082 out:
1083 	return found;
1084 }
1085 
1086 /* Get path information necessary for adding watches. */
1087 static int audit_get_nd(char *path, struct nameidata **ndp,
1088 			struct nameidata **ndw)
1089 {
1090 	struct nameidata *ndparent, *ndwatch;
1091 	int err;
1092 
1093 	ndparent = kmalloc(sizeof(*ndparent), GFP_KERNEL);
1094 	if (unlikely(!ndparent))
1095 		return -ENOMEM;
1096 
1097 	ndwatch = kmalloc(sizeof(*ndwatch), GFP_KERNEL);
1098 	if (unlikely(!ndwatch)) {
1099 		kfree(ndparent);
1100 		return -ENOMEM;
1101 	}
1102 
1103 	err = path_lookup(path, LOOKUP_PARENT, ndparent);
1104 	if (err) {
1105 		kfree(ndparent);
1106 		kfree(ndwatch);
1107 		return err;
1108 	}
1109 
1110 	err = path_lookup(path, 0, ndwatch);
1111 	if (err) {
1112 		kfree(ndwatch);
1113 		ndwatch = NULL;
1114 	}
1115 
1116 	*ndp = ndparent;
1117 	*ndw = ndwatch;
1118 
1119 	return 0;
1120 }
1121 
1122 /* Release resources used for watch path information. */
1123 static void audit_put_nd(struct nameidata *ndp, struct nameidata *ndw)
1124 {
1125 	if (ndp) {
1126 		path_release(ndp);
1127 		kfree(ndp);
1128 	}
1129 	if (ndw) {
1130 		path_release(ndw);
1131 		kfree(ndw);
1132 	}
1133 }
1134 
1135 /* Associate the given rule with an existing parent inotify_watch.
1136  * Caller must hold audit_filter_mutex. */
1137 static void audit_add_to_parent(struct audit_krule *krule,
1138 				struct audit_parent *parent)
1139 {
1140 	struct audit_watch *w, *watch = krule->watch;
1141 	int watch_found = 0;
1142 
1143 	list_for_each_entry(w, &parent->watches, wlist) {
1144 		if (strcmp(watch->path, w->path))
1145 			continue;
1146 
1147 		watch_found = 1;
1148 
1149 		/* put krule's and initial refs to temporary watch */
1150 		audit_put_watch(watch);
1151 		audit_put_watch(watch);
1152 
1153 		audit_get_watch(w);
1154 		krule->watch = watch = w;
1155 		break;
1156 	}
1157 
1158 	if (!watch_found) {
1159 		get_inotify_watch(&parent->wdata);
1160 		watch->parent = parent;
1161 
1162 		list_add(&watch->wlist, &parent->watches);
1163 	}
1164 	list_add(&krule->rlist, &watch->rules);
1165 }
1166 
1167 /* Find a matching watch entry, or add this one.
1168  * Caller must hold audit_filter_mutex. */
1169 static int audit_add_watch(struct audit_krule *krule, struct nameidata *ndp,
1170 			   struct nameidata *ndw)
1171 {
1172 	struct audit_watch *watch = krule->watch;
1173 	struct inotify_watch *i_watch;
1174 	struct audit_parent *parent;
1175 	int ret = 0;
1176 
1177 	/* update watch filter fields */
1178 	if (ndw) {
1179 		watch->dev = ndw->dentry->d_inode->i_sb->s_dev;
1180 		watch->ino = ndw->dentry->d_inode->i_ino;
1181 	}
1182 
1183 	/* The audit_filter_mutex must not be held during inotify calls because
1184 	 * we hold it during inotify event callback processing.  If an existing
1185 	 * inotify watch is found, inotify_find_watch() grabs a reference before
1186 	 * returning.
1187 	 */
1188 	mutex_unlock(&audit_filter_mutex);
1189 
1190 	if (inotify_find_watch(audit_ih, ndp->dentry->d_inode, &i_watch) < 0) {
1191 		parent = audit_init_parent(ndp);
1192 		if (IS_ERR(parent)) {
1193 			/* caller expects mutex locked */
1194 			mutex_lock(&audit_filter_mutex);
1195 			return PTR_ERR(parent);
1196 		}
1197 	} else
1198 		parent = container_of(i_watch, struct audit_parent, wdata);
1199 
1200 	mutex_lock(&audit_filter_mutex);
1201 
1202 	/* parent was moved before we took audit_filter_mutex */
1203 	if (parent->flags & AUDIT_PARENT_INVALID)
1204 		ret = -ENOENT;
1205 	else
1206 		audit_add_to_parent(krule, parent);
1207 
1208 	/* match get in audit_init_parent or inotify_find_watch */
1209 	put_inotify_watch(&parent->wdata);
1210 	return ret;
1211 }
1212 
1213 /* Add rule to given filterlist if not a duplicate. */
1214 static inline int audit_add_rule(struct audit_entry *entry,
1215 				 struct list_head *list)
1216 {
1217 	struct audit_entry *e;
1218 	struct audit_field *inode_f = entry->rule.inode_f;
1219 	struct audit_watch *watch = entry->rule.watch;
1220 	struct nameidata *ndp = NULL, *ndw = NULL;
1221 	int h, err;
1222 #ifdef CONFIG_AUDITSYSCALL
1223 	int dont_count = 0;
1224 
1225 	/* If either of these, don't count towards total */
1226 	if (entry->rule.listnr == AUDIT_FILTER_USER ||
1227 		entry->rule.listnr == AUDIT_FILTER_TYPE)
1228 		dont_count = 1;
1229 #endif
1230 
1231 	if (inode_f) {
1232 		h = audit_hash_ino(inode_f->val);
1233 		list = &audit_inode_hash[h];
1234 	}
1235 
1236 	mutex_lock(&audit_filter_mutex);
1237 	e = audit_find_rule(entry, list);
1238 	mutex_unlock(&audit_filter_mutex);
1239 	if (e) {
1240 		err = -EEXIST;
1241 		goto error;
1242 	}
1243 
1244 	/* Avoid calling path_lookup under audit_filter_mutex. */
1245 	if (watch) {
1246 		err = audit_get_nd(watch->path, &ndp, &ndw);
1247 		if (err)
1248 			goto error;
1249 	}
1250 
1251 	mutex_lock(&audit_filter_mutex);
1252 	if (watch) {
1253 		/* audit_filter_mutex is dropped and re-taken during this call */
1254 		err = audit_add_watch(&entry->rule, ndp, ndw);
1255 		if (err) {
1256 			mutex_unlock(&audit_filter_mutex);
1257 			goto error;
1258 		}
1259 		h = audit_hash_ino((u32)watch->ino);
1260 		list = &audit_inode_hash[h];
1261 	}
1262 
1263 	if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
1264 		list_add_rcu(&entry->list, list);
1265 		entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
1266 	} else {
1267 		list_add_tail_rcu(&entry->list, list);
1268 	}
1269 #ifdef CONFIG_AUDITSYSCALL
1270 	if (!dont_count)
1271 		audit_n_rules++;
1272 
1273 	if (!audit_match_signal(entry))
1274 		audit_signals++;
1275 #endif
1276 	mutex_unlock(&audit_filter_mutex);
1277 
1278 	audit_put_nd(ndp, ndw);		/* NULL args OK */
1279  	return 0;
1280 
1281 error:
1282 	audit_put_nd(ndp, ndw);		/* NULL args OK */
1283 	if (watch)
1284 		audit_put_watch(watch); /* tmp watch, matches initial get */
1285 	return err;
1286 }
1287 
1288 /* Remove an existing rule from filterlist. */
1289 static inline int audit_del_rule(struct audit_entry *entry,
1290 				 struct list_head *list)
1291 {
1292 	struct audit_entry  *e;
1293 	struct audit_field *inode_f = entry->rule.inode_f;
1294 	struct audit_watch *watch, *tmp_watch = entry->rule.watch;
1295 	LIST_HEAD(inotify_list);
1296 	int h, ret = 0;
1297 #ifdef CONFIG_AUDITSYSCALL
1298 	int dont_count = 0;
1299 
1300 	/* If either of these, don't count towards total */
1301 	if (entry->rule.listnr == AUDIT_FILTER_USER ||
1302 		entry->rule.listnr == AUDIT_FILTER_TYPE)
1303 		dont_count = 1;
1304 #endif
1305 
1306 	if (inode_f) {
1307 		h = audit_hash_ino(inode_f->val);
1308 		list = &audit_inode_hash[h];
1309 	}
1310 
1311 	mutex_lock(&audit_filter_mutex);
1312 	e = audit_find_rule(entry, list);
1313 	if (!e) {
1314 		mutex_unlock(&audit_filter_mutex);
1315 		ret = -ENOENT;
1316 		goto out;
1317 	}
1318 
1319 	watch = e->rule.watch;
1320 	if (watch) {
1321 		struct audit_parent *parent = watch->parent;
1322 
1323 		list_del(&e->rule.rlist);
1324 
1325 		if (list_empty(&watch->rules)) {
1326 			audit_remove_watch(watch);
1327 
1328 			if (list_empty(&parent->watches)) {
1329 				/* Put parent on the inotify un-registration
1330 				 * list.  Grab a reference before releasing
1331 				 * audit_filter_mutex, to be released in
1332 				 * audit_inotify_unregister(). */
1333 				list_add(&parent->ilist, &inotify_list);
1334 				get_inotify_watch(&parent->wdata);
1335 			}
1336 		}
1337 	}
1338 
1339 	list_del_rcu(&e->list);
1340 	call_rcu(&e->rcu, audit_free_rule_rcu);
1341 
1342 #ifdef CONFIG_AUDITSYSCALL
1343 	if (!dont_count)
1344 		audit_n_rules--;
1345 
1346 	if (!audit_match_signal(entry))
1347 		audit_signals--;
1348 #endif
1349 	mutex_unlock(&audit_filter_mutex);
1350 
1351 	if (!list_empty(&inotify_list))
1352 		audit_inotify_unregister(&inotify_list);
1353 
1354 out:
1355 	if (tmp_watch)
1356 		audit_put_watch(tmp_watch); /* match initial get */
1357 
1358 	return ret;
1359 }
1360 
1361 /* List rules using struct audit_rule.  Exists for backward
1362  * compatibility with userspace. */
1363 static void audit_list(int pid, int seq, struct sk_buff_head *q)
1364 {
1365 	struct sk_buff *skb;
1366 	struct audit_entry *entry;
1367 	int i;
1368 
1369 	/* This is a blocking read, so use audit_filter_mutex instead of rcu
1370 	 * iterator to sync with list writers. */
1371 	for (i=0; i<AUDIT_NR_FILTERS; i++) {
1372 		list_for_each_entry(entry, &audit_filter_list[i], list) {
1373 			struct audit_rule *rule;
1374 
1375 			rule = audit_krule_to_rule(&entry->rule);
1376 			if (unlikely(!rule))
1377 				break;
1378 			skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1379 					 rule, sizeof(*rule));
1380 			if (skb)
1381 				skb_queue_tail(q, skb);
1382 			kfree(rule);
1383 		}
1384 	}
1385 	for (i = 0; i < AUDIT_INODE_BUCKETS; i++) {
1386 		list_for_each_entry(entry, &audit_inode_hash[i], list) {
1387 			struct audit_rule *rule;
1388 
1389 			rule = audit_krule_to_rule(&entry->rule);
1390 			if (unlikely(!rule))
1391 				break;
1392 			skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1393 					 rule, sizeof(*rule));
1394 			if (skb)
1395 				skb_queue_tail(q, skb);
1396 			kfree(rule);
1397 		}
1398 	}
1399 	skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
1400 	if (skb)
1401 		skb_queue_tail(q, skb);
1402 }
1403 
1404 /* List rules using struct audit_rule_data. */
1405 static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
1406 {
1407 	struct sk_buff *skb;
1408 	struct audit_entry *e;
1409 	int i;
1410 
1411 	/* This is a blocking read, so use audit_filter_mutex instead of rcu
1412 	 * iterator to sync with list writers. */
1413 	for (i=0; i<AUDIT_NR_FILTERS; i++) {
1414 		list_for_each_entry(e, &audit_filter_list[i], list) {
1415 			struct audit_rule_data *data;
1416 
1417 			data = audit_krule_to_data(&e->rule);
1418 			if (unlikely(!data))
1419 				break;
1420 			skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1421 					 data, sizeof(*data) + data->buflen);
1422 			if (skb)
1423 				skb_queue_tail(q, skb);
1424 			kfree(data);
1425 		}
1426 	}
1427 	for (i=0; i< AUDIT_INODE_BUCKETS; i++) {
1428 		list_for_each_entry(e, &audit_inode_hash[i], list) {
1429 			struct audit_rule_data *data;
1430 
1431 			data = audit_krule_to_data(&e->rule);
1432 			if (unlikely(!data))
1433 				break;
1434 			skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1435 					 data, sizeof(*data) + data->buflen);
1436 			if (skb)
1437 				skb_queue_tail(q, skb);
1438 			kfree(data);
1439 		}
1440 	}
1441 	skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1442 	if (skb)
1443 		skb_queue_tail(q, skb);
1444 }
1445 
1446 /* Log rule additions and removals */
1447 static void audit_log_rule_change(uid_t loginuid, u32 sid, char *action,
1448 				  struct audit_krule *rule, int res)
1449 {
1450 	struct audit_buffer *ab;
1451 
1452 	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1453 	if (!ab)
1454 		return;
1455 	audit_log_format(ab, "auid=%u", loginuid);
1456 	if (sid) {
1457 		char *ctx = NULL;
1458 		u32 len;
1459 		if (selinux_sid_to_string(sid, &ctx, &len))
1460 			audit_log_format(ab, " ssid=%u", sid);
1461 		else
1462 			audit_log_format(ab, " subj=%s", ctx);
1463 		kfree(ctx);
1464 	}
1465 	audit_log_format(ab, " op=%s rule key=", action);
1466 	if (rule->filterkey)
1467 		audit_log_untrustedstring(ab, rule->filterkey);
1468 	else
1469 		audit_log_format(ab, "(null)");
1470 	audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1471 	audit_log_end(ab);
1472 }
1473 
1474 /**
1475  * audit_receive_filter - apply all rules to the specified message type
1476  * @type: audit message type
1477  * @pid: target pid for netlink audit messages
1478  * @uid: target uid for netlink audit messages
1479  * @seq: netlink audit message sequence (serial) number
1480  * @data: payload data
1481  * @datasz: size of payload data
1482  * @loginuid: loginuid of sender
1483  * @sid: SE Linux Security ID of sender
1484  */
1485 int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
1486 			 size_t datasz, uid_t loginuid, u32 sid)
1487 {
1488 	struct task_struct *tsk;
1489 	struct audit_netlink_list *dest;
1490 	int err = 0;
1491 	struct audit_entry *entry;
1492 
1493 	switch (type) {
1494 	case AUDIT_LIST:
1495 	case AUDIT_LIST_RULES:
1496 		/* We can't just spew out the rules here because we might fill
1497 		 * the available socket buffer space and deadlock waiting for
1498 		 * auditctl to read from it... which isn't ever going to
1499 		 * happen if we're actually running in the context of auditctl
1500 		 * trying to _send_ the stuff */
1501 
1502 		dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1503 		if (!dest)
1504 			return -ENOMEM;
1505 		dest->pid = pid;
1506 		skb_queue_head_init(&dest->q);
1507 
1508 		mutex_lock(&audit_filter_mutex);
1509 		if (type == AUDIT_LIST)
1510 			audit_list(pid, seq, &dest->q);
1511 		else
1512 			audit_list_rules(pid, seq, &dest->q);
1513 		mutex_unlock(&audit_filter_mutex);
1514 
1515 		tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1516 		if (IS_ERR(tsk)) {
1517 			skb_queue_purge(&dest->q);
1518 			kfree(dest);
1519 			err = PTR_ERR(tsk);
1520 		}
1521 		break;
1522 	case AUDIT_ADD:
1523 	case AUDIT_ADD_RULE:
1524 		if (type == AUDIT_ADD)
1525 			entry = audit_rule_to_entry(data);
1526 		else
1527 			entry = audit_data_to_entry(data, datasz);
1528 		if (IS_ERR(entry))
1529 			return PTR_ERR(entry);
1530 
1531 		err = audit_add_rule(entry,
1532 				     &audit_filter_list[entry->rule.listnr]);
1533 		audit_log_rule_change(loginuid, sid, "add", &entry->rule, !err);
1534 
1535 		if (err)
1536 			audit_free_rule(entry);
1537 		break;
1538 	case AUDIT_DEL:
1539 	case AUDIT_DEL_RULE:
1540 		if (type == AUDIT_DEL)
1541 			entry = audit_rule_to_entry(data);
1542 		else
1543 			entry = audit_data_to_entry(data, datasz);
1544 		if (IS_ERR(entry))
1545 			return PTR_ERR(entry);
1546 
1547 		err = audit_del_rule(entry,
1548 				     &audit_filter_list[entry->rule.listnr]);
1549 		audit_log_rule_change(loginuid, sid, "remove", &entry->rule,
1550 				      !err);
1551 
1552 		audit_free_rule(entry);
1553 		break;
1554 	default:
1555 		return -EINVAL;
1556 	}
1557 
1558 	return err;
1559 }
1560 
1561 int audit_comparator(const u32 left, const u32 op, const u32 right)
1562 {
1563 	switch (op) {
1564 	case AUDIT_EQUAL:
1565 		return (left == right);
1566 	case AUDIT_NOT_EQUAL:
1567 		return (left != right);
1568 	case AUDIT_LESS_THAN:
1569 		return (left < right);
1570 	case AUDIT_LESS_THAN_OR_EQUAL:
1571 		return (left <= right);
1572 	case AUDIT_GREATER_THAN:
1573 		return (left > right);
1574 	case AUDIT_GREATER_THAN_OR_EQUAL:
1575 		return (left >= right);
1576 	case AUDIT_BIT_MASK:
1577 		return (left & right);
1578 	case AUDIT_BIT_TEST:
1579 		return ((left & right) == right);
1580 	}
1581 	BUG();
1582 	return 0;
1583 }
1584 
1585 /* Compare given dentry name with last component in given path,
1586  * return of 0 indicates a match. */
1587 int audit_compare_dname_path(const char *dname, const char *path,
1588 			     int *dirlen)
1589 {
1590 	int dlen, plen;
1591 	const char *p;
1592 
1593 	if (!dname || !path)
1594 		return 1;
1595 
1596 	dlen = strlen(dname);
1597 	plen = strlen(path);
1598 	if (plen < dlen)
1599 		return 1;
1600 
1601 	/* disregard trailing slashes */
1602 	p = path + plen - 1;
1603 	while ((*p == '/') && (p > path))
1604 		p--;
1605 
1606 	/* find last path component */
1607 	p = p - dlen + 1;
1608 	if (p < path)
1609 		return 1;
1610 	else if (p > path) {
1611 		if (*--p != '/')
1612 			return 1;
1613 		else
1614 			p++;
1615 	}
1616 
1617 	/* return length of path's directory component */
1618 	if (dirlen)
1619 		*dirlen = p - path;
1620 	return strncmp(p, dname, dlen);
1621 }
1622 
1623 static int audit_filter_user_rules(struct netlink_skb_parms *cb,
1624 				   struct audit_krule *rule,
1625 				   enum audit_state *state)
1626 {
1627 	int i;
1628 
1629 	for (i = 0; i < rule->field_count; i++) {
1630 		struct audit_field *f = &rule->fields[i];
1631 		int result = 0;
1632 
1633 		switch (f->type) {
1634 		case AUDIT_PID:
1635 			result = audit_comparator(cb->creds.pid, f->op, f->val);
1636 			break;
1637 		case AUDIT_UID:
1638 			result = audit_comparator(cb->creds.uid, f->op, f->val);
1639 			break;
1640 		case AUDIT_GID:
1641 			result = audit_comparator(cb->creds.gid, f->op, f->val);
1642 			break;
1643 		case AUDIT_LOGINUID:
1644 			result = audit_comparator(cb->loginuid, f->op, f->val);
1645 			break;
1646 		}
1647 
1648 		if (!result)
1649 			return 0;
1650 	}
1651 	switch (rule->action) {
1652 	case AUDIT_NEVER:    *state = AUDIT_DISABLED;	    break;
1653 	case AUDIT_ALWAYS:   *state = AUDIT_RECORD_CONTEXT; break;
1654 	}
1655 	return 1;
1656 }
1657 
1658 int audit_filter_user(struct netlink_skb_parms *cb, int type)
1659 {
1660 	enum audit_state state = AUDIT_DISABLED;
1661 	struct audit_entry *e;
1662 	int ret = 1;
1663 
1664 	rcu_read_lock();
1665 	list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1666 		if (audit_filter_user_rules(cb, &e->rule, &state)) {
1667 			if (state == AUDIT_DISABLED)
1668 				ret = 0;
1669 			break;
1670 		}
1671 	}
1672 	rcu_read_unlock();
1673 
1674 	return ret; /* Audit by default */
1675 }
1676 
1677 int audit_filter_type(int type)
1678 {
1679 	struct audit_entry *e;
1680 	int result = 0;
1681 
1682 	rcu_read_lock();
1683 	if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1684 		goto unlock_and_return;
1685 
1686 	list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1687 				list) {
1688 		int i;
1689 		for (i = 0; i < e->rule.field_count; i++) {
1690 			struct audit_field *f = &e->rule.fields[i];
1691 			if (f->type == AUDIT_MSGTYPE) {
1692 				result = audit_comparator(type, f->op, f->val);
1693 				if (!result)
1694 					break;
1695 			}
1696 		}
1697 		if (result)
1698 			goto unlock_and_return;
1699 	}
1700 unlock_and_return:
1701 	rcu_read_unlock();
1702 	return result;
1703 }
1704 
1705 /* Check to see if the rule contains any selinux fields.  Returns 1 if there
1706    are selinux fields specified in the rule, 0 otherwise. */
1707 static inline int audit_rule_has_selinux(struct audit_krule *rule)
1708 {
1709 	int i;
1710 
1711 	for (i = 0; i < rule->field_count; i++) {
1712 		struct audit_field *f = &rule->fields[i];
1713 		switch (f->type) {
1714 		case AUDIT_SUBJ_USER:
1715 		case AUDIT_SUBJ_ROLE:
1716 		case AUDIT_SUBJ_TYPE:
1717 		case AUDIT_SUBJ_SEN:
1718 		case AUDIT_SUBJ_CLR:
1719 		case AUDIT_OBJ_USER:
1720 		case AUDIT_OBJ_ROLE:
1721 		case AUDIT_OBJ_TYPE:
1722 		case AUDIT_OBJ_LEV_LOW:
1723 		case AUDIT_OBJ_LEV_HIGH:
1724 			return 1;
1725 		}
1726 	}
1727 
1728 	return 0;
1729 }
1730 
1731 /* This function will re-initialize the se_rule field of all applicable rules.
1732  * It will traverse the filter lists serarching for rules that contain selinux
1733  * specific filter fields.  When such a rule is found, it is copied, the
1734  * selinux field is re-initialized, and the old rule is replaced with the
1735  * updated rule. */
1736 int selinux_audit_rule_update(void)
1737 {
1738 	struct audit_entry *entry, *n, *nentry;
1739 	struct audit_watch *watch;
1740 	int i, err = 0;
1741 
1742 	/* audit_filter_mutex synchronizes the writers */
1743 	mutex_lock(&audit_filter_mutex);
1744 
1745 	for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1746 		list_for_each_entry_safe(entry, n, &audit_filter_list[i], list) {
1747 			if (!audit_rule_has_selinux(&entry->rule))
1748 				continue;
1749 
1750 			watch = entry->rule.watch;
1751 			nentry = audit_dupe_rule(&entry->rule, watch);
1752 			if (unlikely(IS_ERR(nentry))) {
1753 				/* save the first error encountered for the
1754 				 * return value */
1755 				if (!err)
1756 					err = PTR_ERR(nentry);
1757 				audit_panic("error updating selinux filters");
1758 				if (watch)
1759 					list_del(&entry->rule.rlist);
1760 				list_del_rcu(&entry->list);
1761 			} else {
1762 				if (watch) {
1763 					list_add(&nentry->rule.rlist,
1764 						 &watch->rules);
1765 					list_del(&entry->rule.rlist);
1766 				}
1767 				list_replace_rcu(&entry->list, &nentry->list);
1768 			}
1769 			call_rcu(&entry->rcu, audit_free_rule_rcu);
1770 		}
1771 	}
1772 
1773 	mutex_unlock(&audit_filter_mutex);
1774 
1775 	return err;
1776 }
1777 
1778 /* Update watch data in audit rules based on inotify events. */
1779 void audit_handle_ievent(struct inotify_watch *i_watch, u32 wd, u32 mask,
1780 			 u32 cookie, const char *dname, struct inode *inode)
1781 {
1782 	struct audit_parent *parent;
1783 
1784 	parent = container_of(i_watch, struct audit_parent, wdata);
1785 
1786 	if (mask & (IN_CREATE|IN_MOVED_TO) && inode)
1787 		audit_update_watch(parent, dname, inode->i_sb->s_dev,
1788 				   inode->i_ino, 0);
1789 	else if (mask & (IN_DELETE|IN_MOVED_FROM))
1790 		audit_update_watch(parent, dname, (dev_t)-1, (unsigned long)-1, 1);
1791 	/* inotify automatically removes the watch and sends IN_IGNORED */
1792 	else if (mask & (IN_DELETE_SELF|IN_UNMOUNT))
1793 		audit_remove_parent_watches(parent);
1794 	/* inotify does not remove the watch, so remove it manually */
1795 	else if(mask & IN_MOVE_SELF) {
1796 		audit_remove_parent_watches(parent);
1797 		inotify_remove_watch_locked(audit_ih, i_watch);
1798 	} else if (mask & IN_IGNORED)
1799 		put_inotify_watch(i_watch);
1800 }
1801