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[PATCH] audit: support for object context filters
[deliverable/linux.git] / kernel / auditfilter.c
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 /* Common user-space to kernel rule translation. */
283 static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule)
284 {
285 unsigned listnr;
286 struct audit_entry *entry;
287 int i, err;
288
289 err = -EINVAL;
290 listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
291 switch(listnr) {
292 default:
293 goto exit_err;
294 case AUDIT_FILTER_USER:
295 case AUDIT_FILTER_TYPE:
296 #ifdef CONFIG_AUDITSYSCALL
297 case AUDIT_FILTER_ENTRY:
298 case AUDIT_FILTER_EXIT:
299 case AUDIT_FILTER_TASK:
300 #endif
301 ;
302 }
303 if (unlikely(rule->action == AUDIT_POSSIBLE)) {
304 printk(KERN_ERR "AUDIT_POSSIBLE is deprecated\n");
305 goto exit_err;
306 }
307 if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
308 goto exit_err;
309 if (rule->field_count > AUDIT_MAX_FIELDS)
310 goto exit_err;
311
312 err = -ENOMEM;
313 entry = audit_init_entry(rule->field_count);
314 if (!entry)
315 goto exit_err;
316
317 entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
318 entry->rule.listnr = listnr;
319 entry->rule.action = rule->action;
320 entry->rule.field_count = rule->field_count;
321
322 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
323 entry->rule.mask[i] = rule->mask[i];
324
325 return entry;
326
327 exit_err:
328 return ERR_PTR(err);
329 }
330
331 /* Translate struct audit_rule to kernel's rule respresentation.
332 * Exists for backward compatibility with userspace. */
333 static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
334 {
335 struct audit_entry *entry;
336 struct audit_field *f;
337 int err = 0;
338 int i;
339
340 entry = audit_to_entry_common(rule);
341 if (IS_ERR(entry))
342 goto exit_nofree;
343
344 for (i = 0; i < rule->field_count; i++) {
345 struct audit_field *f = &entry->rule.fields[i];
346
347 f->op = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS);
348 f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS);
349 f->val = rule->values[i];
350
351 err = -EINVAL;
352 switch(f->type) {
353 default:
354 goto exit_free;
355 case AUDIT_PID:
356 case AUDIT_UID:
357 case AUDIT_EUID:
358 case AUDIT_SUID:
359 case AUDIT_FSUID:
360 case AUDIT_GID:
361 case AUDIT_EGID:
362 case AUDIT_SGID:
363 case AUDIT_FSGID:
364 case AUDIT_LOGINUID:
365 case AUDIT_PERS:
366 case AUDIT_ARCH:
367 case AUDIT_MSGTYPE:
368 case AUDIT_DEVMAJOR:
369 case AUDIT_DEVMINOR:
370 case AUDIT_EXIT:
371 case AUDIT_SUCCESS:
372 case AUDIT_ARG0:
373 case AUDIT_ARG1:
374 case AUDIT_ARG2:
375 case AUDIT_ARG3:
376 break;
377 case AUDIT_INODE:
378 err = audit_to_inode(&entry->rule, f);
379 if (err)
380 goto exit_free;
381 break;
382 }
383
384 entry->rule.vers_ops = (f->op & AUDIT_OPERATORS) ? 2 : 1;
385
386 /* Support for legacy operators where
387 * AUDIT_NEGATE bit signifies != and otherwise assumes == */
388 if (f->op & AUDIT_NEGATE)
389 f->op = AUDIT_NOT_EQUAL;
390 else if (!f->op)
391 f->op = AUDIT_EQUAL;
392 else if (f->op == AUDIT_OPERATORS) {
393 err = -EINVAL;
394 goto exit_free;
395 }
396 }
397
398 f = entry->rule.inode_f;
399 if (f) {
400 switch(f->op) {
401 case AUDIT_NOT_EQUAL:
402 entry->rule.inode_f = NULL;
403 case AUDIT_EQUAL:
404 break;
405 default:
406 goto exit_free;
407 }
408 }
409
410 exit_nofree:
411 return entry;
412
413 exit_free:
414 audit_free_rule(entry);
415 return ERR_PTR(err);
416 }
417
418 /* Translate struct audit_rule_data to kernel's rule respresentation. */
419 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
420 size_t datasz)
421 {
422 int err = 0;
423 struct audit_entry *entry;
424 struct audit_field *f;
425 void *bufp;
426 size_t remain = datasz - sizeof(struct audit_rule_data);
427 int i;
428 char *str;
429
430 entry = audit_to_entry_common((struct audit_rule *)data);
431 if (IS_ERR(entry))
432 goto exit_nofree;
433
434 bufp = data->buf;
435 entry->rule.vers_ops = 2;
436 for (i = 0; i < data->field_count; i++) {
437 struct audit_field *f = &entry->rule.fields[i];
438
439 err = -EINVAL;
440 if (!(data->fieldflags[i] & AUDIT_OPERATORS) ||
441 data->fieldflags[i] & ~AUDIT_OPERATORS)
442 goto exit_free;
443
444 f->op = data->fieldflags[i] & AUDIT_OPERATORS;
445 f->type = data->fields[i];
446 f->val = data->values[i];
447 f->se_str = NULL;
448 f->se_rule = NULL;
449 switch(f->type) {
450 case AUDIT_PID:
451 case AUDIT_UID:
452 case AUDIT_EUID:
453 case AUDIT_SUID:
454 case AUDIT_FSUID:
455 case AUDIT_GID:
456 case AUDIT_EGID:
457 case AUDIT_SGID:
458 case AUDIT_FSGID:
459 case AUDIT_LOGINUID:
460 case AUDIT_PERS:
461 case AUDIT_ARCH:
462 case AUDIT_MSGTYPE:
463 case AUDIT_PPID:
464 case AUDIT_DEVMAJOR:
465 case AUDIT_DEVMINOR:
466 case AUDIT_EXIT:
467 case AUDIT_SUCCESS:
468 case AUDIT_ARG0:
469 case AUDIT_ARG1:
470 case AUDIT_ARG2:
471 case AUDIT_ARG3:
472 break;
473 case AUDIT_SUBJ_USER:
474 case AUDIT_SUBJ_ROLE:
475 case AUDIT_SUBJ_TYPE:
476 case AUDIT_SUBJ_SEN:
477 case AUDIT_SUBJ_CLR:
478 case AUDIT_OBJ_USER:
479 case AUDIT_OBJ_ROLE:
480 case AUDIT_OBJ_TYPE:
481 case AUDIT_OBJ_LEV_LOW:
482 case AUDIT_OBJ_LEV_HIGH:
483 str = audit_unpack_string(&bufp, &remain, f->val);
484 if (IS_ERR(str))
485 goto exit_free;
486 entry->rule.buflen += f->val;
487
488 err = selinux_audit_rule_init(f->type, f->op, str,
489 &f->se_rule);
490 /* Keep currently invalid fields around in case they
491 * become valid after a policy reload. */
492 if (err == -EINVAL) {
493 printk(KERN_WARNING "audit rule for selinux "
494 "\'%s\' is invalid\n", str);
495 err = 0;
496 }
497 if (err) {
498 kfree(str);
499 goto exit_free;
500 } else
501 f->se_str = str;
502 break;
503 case AUDIT_WATCH:
504 str = audit_unpack_string(&bufp, &remain, f->val);
505 if (IS_ERR(str))
506 goto exit_free;
507 entry->rule.buflen += f->val;
508
509 err = audit_to_watch(&entry->rule, str, f->val, f->op);
510 if (err) {
511 kfree(str);
512 goto exit_free;
513 }
514 break;
515 case AUDIT_INODE:
516 err = audit_to_inode(&entry->rule, f);
517 if (err)
518 goto exit_free;
519 break;
520 case AUDIT_FILTERKEY:
521 err = -EINVAL;
522 if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
523 goto exit_free;
524 str = audit_unpack_string(&bufp, &remain, f->val);
525 if (IS_ERR(str))
526 goto exit_free;
527 entry->rule.buflen += f->val;
528 entry->rule.filterkey = str;
529 break;
530 default:
531 goto exit_free;
532 }
533 }
534
535 f = entry->rule.inode_f;
536 if (f) {
537 switch(f->op) {
538 case AUDIT_NOT_EQUAL:
539 entry->rule.inode_f = NULL;
540 case AUDIT_EQUAL:
541 break;
542 default:
543 goto exit_free;
544 }
545 }
546
547 exit_nofree:
548 return entry;
549
550 exit_free:
551 audit_free_rule(entry);
552 return ERR_PTR(err);
553 }
554
555 /* Pack a filter field's string representation into data block. */
556 static inline size_t audit_pack_string(void **bufp, char *str)
557 {
558 size_t len = strlen(str);
559
560 memcpy(*bufp, str, len);
561 *bufp += len;
562
563 return len;
564 }
565
566 /* Translate kernel rule respresentation to struct audit_rule.
567 * Exists for backward compatibility with userspace. */
568 static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
569 {
570 struct audit_rule *rule;
571 int i;
572
573 rule = kmalloc(sizeof(*rule), GFP_KERNEL);
574 if (unlikely(!rule))
575 return NULL;
576 memset(rule, 0, sizeof(*rule));
577
578 rule->flags = krule->flags | krule->listnr;
579 rule->action = krule->action;
580 rule->field_count = krule->field_count;
581 for (i = 0; i < rule->field_count; i++) {
582 rule->values[i] = krule->fields[i].val;
583 rule->fields[i] = krule->fields[i].type;
584
585 if (krule->vers_ops == 1) {
586 if (krule->fields[i].op & AUDIT_NOT_EQUAL)
587 rule->fields[i] |= AUDIT_NEGATE;
588 } else {
589 rule->fields[i] |= krule->fields[i].op;
590 }
591 }
592 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
593
594 return rule;
595 }
596
597 /* Translate kernel rule respresentation to struct audit_rule_data. */
598 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
599 {
600 struct audit_rule_data *data;
601 void *bufp;
602 int i;
603
604 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
605 if (unlikely(!data))
606 return NULL;
607 memset(data, 0, sizeof(*data));
608
609 data->flags = krule->flags | krule->listnr;
610 data->action = krule->action;
611 data->field_count = krule->field_count;
612 bufp = data->buf;
613 for (i = 0; i < data->field_count; i++) {
614 struct audit_field *f = &krule->fields[i];
615
616 data->fields[i] = f->type;
617 data->fieldflags[i] = f->op;
618 switch(f->type) {
619 case AUDIT_SUBJ_USER:
620 case AUDIT_SUBJ_ROLE:
621 case AUDIT_SUBJ_TYPE:
622 case AUDIT_SUBJ_SEN:
623 case AUDIT_SUBJ_CLR:
624 case AUDIT_OBJ_USER:
625 case AUDIT_OBJ_ROLE:
626 case AUDIT_OBJ_TYPE:
627 case AUDIT_OBJ_LEV_LOW:
628 case AUDIT_OBJ_LEV_HIGH:
629 data->buflen += data->values[i] =
630 audit_pack_string(&bufp, f->se_str);
631 break;
632 case AUDIT_WATCH:
633 data->buflen += data->values[i] =
634 audit_pack_string(&bufp, krule->watch->path);
635 break;
636 case AUDIT_FILTERKEY:
637 data->buflen += data->values[i] =
638 audit_pack_string(&bufp, krule->filterkey);
639 break;
640 default:
641 data->values[i] = f->val;
642 }
643 }
644 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
645
646 return data;
647 }
648
649 /* Compare two rules in kernel format. Considered success if rules
650 * don't match. */
651 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
652 {
653 int i;
654
655 if (a->flags != b->flags ||
656 a->listnr != b->listnr ||
657 a->action != b->action ||
658 a->field_count != b->field_count)
659 return 1;
660
661 for (i = 0; i < a->field_count; i++) {
662 if (a->fields[i].type != b->fields[i].type ||
663 a->fields[i].op != b->fields[i].op)
664 return 1;
665
666 switch(a->fields[i].type) {
667 case AUDIT_SUBJ_USER:
668 case AUDIT_SUBJ_ROLE:
669 case AUDIT_SUBJ_TYPE:
670 case AUDIT_SUBJ_SEN:
671 case AUDIT_SUBJ_CLR:
672 case AUDIT_OBJ_USER:
673 case AUDIT_OBJ_ROLE:
674 case AUDIT_OBJ_TYPE:
675 case AUDIT_OBJ_LEV_LOW:
676 case AUDIT_OBJ_LEV_HIGH:
677 if (strcmp(a->fields[i].se_str, b->fields[i].se_str))
678 return 1;
679 break;
680 case AUDIT_WATCH:
681 if (strcmp(a->watch->path, b->watch->path))
682 return 1;
683 break;
684 case AUDIT_FILTERKEY:
685 /* both filterkeys exist based on above type compare */
686 if (strcmp(a->filterkey, b->filterkey))
687 return 1;
688 break;
689 default:
690 if (a->fields[i].val != b->fields[i].val)
691 return 1;
692 }
693 }
694
695 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
696 if (a->mask[i] != b->mask[i])
697 return 1;
698
699 return 0;
700 }
701
702 /* Duplicate the given audit watch. The new watch's rules list is initialized
703 * to an empty list and wlist is undefined. */
704 static struct audit_watch *audit_dupe_watch(struct audit_watch *old)
705 {
706 char *path;
707 struct audit_watch *new;
708
709 path = kstrdup(old->path, GFP_KERNEL);
710 if (unlikely(!path))
711 return ERR_PTR(-ENOMEM);
712
713 new = audit_init_watch(path);
714 if (unlikely(IS_ERR(new))) {
715 kfree(path);
716 goto out;
717 }
718
719 new->dev = old->dev;
720 new->ino = old->ino;
721 get_inotify_watch(&old->parent->wdata);
722 new->parent = old->parent;
723
724 out:
725 return new;
726 }
727
728 /* Duplicate selinux field information. The se_rule is opaque, so must be
729 * re-initialized. */
730 static inline int audit_dupe_selinux_field(struct audit_field *df,
731 struct audit_field *sf)
732 {
733 int ret = 0;
734 char *se_str;
735
736 /* our own copy of se_str */
737 se_str = kstrdup(sf->se_str, GFP_KERNEL);
738 if (unlikely(IS_ERR(se_str)))
739 return -ENOMEM;
740 df->se_str = se_str;
741
742 /* our own (refreshed) copy of se_rule */
743 ret = selinux_audit_rule_init(df->type, df->op, df->se_str,
744 &df->se_rule);
745 /* Keep currently invalid fields around in case they
746 * become valid after a policy reload. */
747 if (ret == -EINVAL) {
748 printk(KERN_WARNING "audit rule for selinux \'%s\' is "
749 "invalid\n", df->se_str);
750 ret = 0;
751 }
752
753 return ret;
754 }
755
756 /* Duplicate an audit rule. This will be a deep copy with the exception
757 * of the watch - that pointer is carried over. The selinux specific fields
758 * will be updated in the copy. The point is to be able to replace the old
759 * rule with the new rule in the filterlist, then free the old rule.
760 * The rlist element is undefined; list manipulations are handled apart from
761 * the initial copy. */
762 static struct audit_entry *audit_dupe_rule(struct audit_krule *old,
763 struct audit_watch *watch)
764 {
765 u32 fcount = old->field_count;
766 struct audit_entry *entry;
767 struct audit_krule *new;
768 char *fk;
769 int i, err = 0;
770
771 entry = audit_init_entry(fcount);
772 if (unlikely(!entry))
773 return ERR_PTR(-ENOMEM);
774
775 new = &entry->rule;
776 new->vers_ops = old->vers_ops;
777 new->flags = old->flags;
778 new->listnr = old->listnr;
779 new->action = old->action;
780 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
781 new->mask[i] = old->mask[i];
782 new->buflen = old->buflen;
783 new->inode_f = old->inode_f;
784 new->watch = NULL;
785 new->field_count = old->field_count;
786 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
787
788 /* deep copy this information, updating the se_rule fields, because
789 * the originals will all be freed when the old rule is freed. */
790 for (i = 0; i < fcount; i++) {
791 switch (new->fields[i].type) {
792 case AUDIT_SUBJ_USER:
793 case AUDIT_SUBJ_ROLE:
794 case AUDIT_SUBJ_TYPE:
795 case AUDIT_SUBJ_SEN:
796 case AUDIT_SUBJ_CLR:
797 case AUDIT_OBJ_USER:
798 case AUDIT_OBJ_ROLE:
799 case AUDIT_OBJ_TYPE:
800 case AUDIT_OBJ_LEV_LOW:
801 case AUDIT_OBJ_LEV_HIGH:
802 err = audit_dupe_selinux_field(&new->fields[i],
803 &old->fields[i]);
804 break;
805 case AUDIT_FILTERKEY:
806 fk = kstrdup(old->filterkey, GFP_KERNEL);
807 if (unlikely(!fk))
808 err = -ENOMEM;
809 else
810 new->filterkey = fk;
811 }
812 if (err) {
813 audit_free_rule(entry);
814 return ERR_PTR(err);
815 }
816 }
817
818 if (watch) {
819 audit_get_watch(watch);
820 new->watch = watch;
821 }
822
823 return entry;
824 }
825
826 /* Update inode info in audit rules based on filesystem event. */
827 static void audit_update_watch(struct audit_parent *parent,
828 const char *dname, dev_t dev,
829 unsigned long ino, unsigned invalidating)
830 {
831 struct audit_watch *owatch, *nwatch, *nextw;
832 struct audit_krule *r, *nextr;
833 struct audit_entry *oentry, *nentry;
834 struct audit_buffer *ab;
835
836 mutex_lock(&audit_filter_mutex);
837 list_for_each_entry_safe(owatch, nextw, &parent->watches, wlist) {
838 if (audit_compare_dname_path(dname, owatch->path, NULL))
839 continue;
840
841 /* If the update involves invalidating rules, do the inode-based
842 * filtering now, so we don't omit records. */
843 if (invalidating &&
844 audit_filter_inodes(current, current->audit_context) == AUDIT_RECORD_CONTEXT)
845 audit_set_auditable(current->audit_context);
846
847 nwatch = audit_dupe_watch(owatch);
848 if (unlikely(IS_ERR(nwatch))) {
849 mutex_unlock(&audit_filter_mutex);
850 audit_panic("error updating watch, skipping");
851 return;
852 }
853 nwatch->dev = dev;
854 nwatch->ino = ino;
855
856 list_for_each_entry_safe(r, nextr, &owatch->rules, rlist) {
857
858 oentry = container_of(r, struct audit_entry, rule);
859 list_del(&oentry->rule.rlist);
860 list_del_rcu(&oentry->list);
861
862 nentry = audit_dupe_rule(&oentry->rule, nwatch);
863 if (unlikely(IS_ERR(nentry)))
864 audit_panic("error updating watch, removing");
865 else {
866 int h = audit_hash_ino((u32)ino);
867 list_add(&nentry->rule.rlist, &nwatch->rules);
868 list_add_rcu(&nentry->list, &audit_inode_hash[h]);
869 }
870
871 call_rcu(&oentry->rcu, audit_free_rule_rcu);
872 }
873
874 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
875 audit_log_format(ab, "audit updated rules specifying watch=");
876 audit_log_untrustedstring(ab, owatch->path);
877 audit_log_format(ab, " with dev=%u ino=%lu\n", dev, ino);
878 audit_log_end(ab);
879
880 audit_remove_watch(owatch);
881 goto add_watch_to_parent; /* event applies to a single watch */
882 }
883 mutex_unlock(&audit_filter_mutex);
884 return;
885
886 add_watch_to_parent:
887 list_add(&nwatch->wlist, &parent->watches);
888 mutex_unlock(&audit_filter_mutex);
889 return;
890 }
891
892 /* Remove all watches & rules associated with a parent that is going away. */
893 static void audit_remove_parent_watches(struct audit_parent *parent)
894 {
895 struct audit_watch *w, *nextw;
896 struct audit_krule *r, *nextr;
897 struct audit_entry *e;
898
899 mutex_lock(&audit_filter_mutex);
900 parent->flags |= AUDIT_PARENT_INVALID;
901 list_for_each_entry_safe(w, nextw, &parent->watches, wlist) {
902 list_for_each_entry_safe(r, nextr, &w->rules, rlist) {
903 e = container_of(r, struct audit_entry, rule);
904 list_del(&r->rlist);
905 list_del_rcu(&e->list);
906 call_rcu(&e->rcu, audit_free_rule_rcu);
907
908 audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
909 "audit implicitly removed rule from list=%d\n",
910 AUDIT_FILTER_EXIT);
911 }
912 audit_remove_watch(w);
913 }
914 mutex_unlock(&audit_filter_mutex);
915 }
916
917 /* Unregister inotify watches for parents on in_list.
918 * Generates an IN_IGNORED event. */
919 static void audit_inotify_unregister(struct list_head *in_list)
920 {
921 struct audit_parent *p, *n;
922
923 list_for_each_entry_safe(p, n, in_list, ilist) {
924 list_del(&p->ilist);
925 inotify_rm_watch(audit_ih, &p->wdata);
926 /* the put matching the get in audit_do_del_rule() */
927 put_inotify_watch(&p->wdata);
928 }
929 }
930
931 /* Find an existing audit rule.
932 * Caller must hold audit_filter_mutex to prevent stale rule data. */
933 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
934 struct list_head *list)
935 {
936 struct audit_entry *e, *found = NULL;
937 int h;
938
939 if (entry->rule.watch) {
940 /* we don't know the inode number, so must walk entire hash */
941 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
942 list = &audit_inode_hash[h];
943 list_for_each_entry(e, list, list)
944 if (!audit_compare_rule(&entry->rule, &e->rule)) {
945 found = e;
946 goto out;
947 }
948 }
949 goto out;
950 }
951
952 list_for_each_entry(e, list, list)
953 if (!audit_compare_rule(&entry->rule, &e->rule)) {
954 found = e;
955 goto out;
956 }
957
958 out:
959 return found;
960 }
961
962 /* Get path information necessary for adding watches. */
963 static int audit_get_nd(char *path, struct nameidata **ndp,
964 struct nameidata **ndw)
965 {
966 struct nameidata *ndparent, *ndwatch;
967 int err;
968
969 ndparent = kmalloc(sizeof(*ndparent), GFP_KERNEL);
970 if (unlikely(!ndparent))
971 return -ENOMEM;
972
973 ndwatch = kmalloc(sizeof(*ndwatch), GFP_KERNEL);
974 if (unlikely(!ndwatch)) {
975 kfree(ndparent);
976 return -ENOMEM;
977 }
978
979 err = path_lookup(path, LOOKUP_PARENT, ndparent);
980 if (err) {
981 kfree(ndparent);
982 kfree(ndwatch);
983 return err;
984 }
985
986 err = path_lookup(path, 0, ndwatch);
987 if (err) {
988 kfree(ndwatch);
989 ndwatch = NULL;
990 }
991
992 *ndp = ndparent;
993 *ndw = ndwatch;
994
995 return 0;
996 }
997
998 /* Release resources used for watch path information. */
999 static void audit_put_nd(struct nameidata *ndp, struct nameidata *ndw)
1000 {
1001 if (ndp) {
1002 path_release(ndp);
1003 kfree(ndp);
1004 }
1005 if (ndw) {
1006 path_release(ndw);
1007 kfree(ndw);
1008 }
1009 }
1010
1011 /* Associate the given rule with an existing parent inotify_watch.
1012 * Caller must hold audit_filter_mutex. */
1013 static void audit_add_to_parent(struct audit_krule *krule,
1014 struct audit_parent *parent)
1015 {
1016 struct audit_watch *w, *watch = krule->watch;
1017 int watch_found = 0;
1018
1019 list_for_each_entry(w, &parent->watches, wlist) {
1020 if (strcmp(watch->path, w->path))
1021 continue;
1022
1023 watch_found = 1;
1024
1025 /* put krule's and initial refs to temporary watch */
1026 audit_put_watch(watch);
1027 audit_put_watch(watch);
1028
1029 audit_get_watch(w);
1030 krule->watch = watch = w;
1031 break;
1032 }
1033
1034 if (!watch_found) {
1035 get_inotify_watch(&parent->wdata);
1036 watch->parent = parent;
1037
1038 list_add(&watch->wlist, &parent->watches);
1039 }
1040 list_add(&krule->rlist, &watch->rules);
1041 }
1042
1043 /* Find a matching watch entry, or add this one.
1044 * Caller must hold audit_filter_mutex. */
1045 static int audit_add_watch(struct audit_krule *krule, struct nameidata *ndp,
1046 struct nameidata *ndw)
1047 {
1048 struct audit_watch *watch = krule->watch;
1049 struct inotify_watch *i_watch;
1050 struct audit_parent *parent;
1051 int ret = 0;
1052
1053 /* update watch filter fields */
1054 if (ndw) {
1055 watch->dev = ndw->dentry->d_inode->i_sb->s_dev;
1056 watch->ino = ndw->dentry->d_inode->i_ino;
1057 }
1058
1059 /* The audit_filter_mutex must not be held during inotify calls because
1060 * we hold it during inotify event callback processing. If an existing
1061 * inotify watch is found, inotify_find_watch() grabs a reference before
1062 * returning.
1063 */
1064 mutex_unlock(&audit_filter_mutex);
1065
1066 if (inotify_find_watch(audit_ih, ndp->dentry->d_inode, &i_watch) < 0) {
1067 parent = audit_init_parent(ndp);
1068 if (IS_ERR(parent)) {
1069 /* caller expects mutex locked */
1070 mutex_lock(&audit_filter_mutex);
1071 return PTR_ERR(parent);
1072 }
1073 } else
1074 parent = container_of(i_watch, struct audit_parent, wdata);
1075
1076 mutex_lock(&audit_filter_mutex);
1077
1078 /* parent was moved before we took audit_filter_mutex */
1079 if (parent->flags & AUDIT_PARENT_INVALID)
1080 ret = -ENOENT;
1081 else
1082 audit_add_to_parent(krule, parent);
1083
1084 /* match get in audit_init_parent or inotify_find_watch */
1085 put_inotify_watch(&parent->wdata);
1086 return ret;
1087 }
1088
1089 /* Add rule to given filterlist if not a duplicate. */
1090 static inline int audit_add_rule(struct audit_entry *entry,
1091 struct list_head *list)
1092 {
1093 struct audit_entry *e;
1094 struct audit_field *inode_f = entry->rule.inode_f;
1095 struct audit_watch *watch = entry->rule.watch;
1096 struct nameidata *ndp, *ndw;
1097 int h, err, putnd_needed = 0;
1098
1099 if (inode_f) {
1100 h = audit_hash_ino(inode_f->val);
1101 list = &audit_inode_hash[h];
1102 }
1103
1104 mutex_lock(&audit_filter_mutex);
1105 e = audit_find_rule(entry, list);
1106 mutex_unlock(&audit_filter_mutex);
1107 if (e) {
1108 err = -EEXIST;
1109 goto error;
1110 }
1111
1112 /* Avoid calling path_lookup under audit_filter_mutex. */
1113 if (watch) {
1114 err = audit_get_nd(watch->path, &ndp, &ndw);
1115 if (err)
1116 goto error;
1117 putnd_needed = 1;
1118 }
1119
1120 mutex_lock(&audit_filter_mutex);
1121 if (watch) {
1122 /* audit_filter_mutex is dropped and re-taken during this call */
1123 err = audit_add_watch(&entry->rule, ndp, ndw);
1124 if (err) {
1125 mutex_unlock(&audit_filter_mutex);
1126 goto error;
1127 }
1128 h = audit_hash_ino((u32)watch->ino);
1129 list = &audit_inode_hash[h];
1130 }
1131
1132 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
1133 list_add_rcu(&entry->list, list);
1134 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
1135 } else {
1136 list_add_tail_rcu(&entry->list, list);
1137 }
1138 mutex_unlock(&audit_filter_mutex);
1139
1140 if (putnd_needed)
1141 audit_put_nd(ndp, ndw);
1142
1143 return 0;
1144
1145 error:
1146 if (putnd_needed)
1147 audit_put_nd(ndp, ndw);
1148 if (watch)
1149 audit_put_watch(watch); /* tmp watch, matches initial get */
1150 return err;
1151 }
1152
1153 /* Remove an existing rule from filterlist. */
1154 static inline int audit_del_rule(struct audit_entry *entry,
1155 struct list_head *list)
1156 {
1157 struct audit_entry *e;
1158 struct audit_field *inode_f = entry->rule.inode_f;
1159 struct audit_watch *watch, *tmp_watch = entry->rule.watch;
1160 LIST_HEAD(inotify_list);
1161 int h, ret = 0;
1162
1163 if (inode_f) {
1164 h = audit_hash_ino(inode_f->val);
1165 list = &audit_inode_hash[h];
1166 }
1167
1168 mutex_lock(&audit_filter_mutex);
1169 e = audit_find_rule(entry, list);
1170 if (!e) {
1171 mutex_unlock(&audit_filter_mutex);
1172 ret = -ENOENT;
1173 goto out;
1174 }
1175
1176 watch = e->rule.watch;
1177 if (watch) {
1178 struct audit_parent *parent = watch->parent;
1179
1180 list_del(&e->rule.rlist);
1181
1182 if (list_empty(&watch->rules)) {
1183 audit_remove_watch(watch);
1184
1185 if (list_empty(&parent->watches)) {
1186 /* Put parent on the inotify un-registration
1187 * list. Grab a reference before releasing
1188 * audit_filter_mutex, to be released in
1189 * audit_inotify_unregister(). */
1190 list_add(&parent->ilist, &inotify_list);
1191 get_inotify_watch(&parent->wdata);
1192 }
1193 }
1194 }
1195
1196 list_del_rcu(&e->list);
1197 call_rcu(&e->rcu, audit_free_rule_rcu);
1198
1199 mutex_unlock(&audit_filter_mutex);
1200
1201 if (!list_empty(&inotify_list))
1202 audit_inotify_unregister(&inotify_list);
1203
1204 out:
1205 if (tmp_watch)
1206 audit_put_watch(tmp_watch); /* match initial get */
1207
1208 return ret;
1209 }
1210
1211 /* List rules using struct audit_rule. Exists for backward
1212 * compatibility with userspace. */
1213 static void audit_list(int pid, int seq, struct sk_buff_head *q)
1214 {
1215 struct sk_buff *skb;
1216 struct audit_entry *entry;
1217 int i;
1218
1219 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1220 * iterator to sync with list writers. */
1221 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1222 list_for_each_entry(entry, &audit_filter_list[i], list) {
1223 struct audit_rule *rule;
1224
1225 rule = audit_krule_to_rule(&entry->rule);
1226 if (unlikely(!rule))
1227 break;
1228 skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1229 rule, sizeof(*rule));
1230 if (skb)
1231 skb_queue_tail(q, skb);
1232 kfree(rule);
1233 }
1234 }
1235 for (i = 0; i < AUDIT_INODE_BUCKETS; i++) {
1236 list_for_each_entry(entry, &audit_inode_hash[i], list) {
1237 struct audit_rule *rule;
1238
1239 rule = audit_krule_to_rule(&entry->rule);
1240 if (unlikely(!rule))
1241 break;
1242 skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1243 rule, sizeof(*rule));
1244 if (skb)
1245 skb_queue_tail(q, skb);
1246 kfree(rule);
1247 }
1248 }
1249 skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
1250 if (skb)
1251 skb_queue_tail(q, skb);
1252 }
1253
1254 /* List rules using struct audit_rule_data. */
1255 static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
1256 {
1257 struct sk_buff *skb;
1258 struct audit_entry *e;
1259 int i;
1260
1261 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1262 * iterator to sync with list writers. */
1263 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1264 list_for_each_entry(e, &audit_filter_list[i], list) {
1265 struct audit_rule_data *data;
1266
1267 data = audit_krule_to_data(&e->rule);
1268 if (unlikely(!data))
1269 break;
1270 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1271 data, sizeof(*data) + data->buflen);
1272 if (skb)
1273 skb_queue_tail(q, skb);
1274 kfree(data);
1275 }
1276 }
1277 for (i=0; i< AUDIT_INODE_BUCKETS; i++) {
1278 list_for_each_entry(e, &audit_inode_hash[i], list) {
1279 struct audit_rule_data *data;
1280
1281 data = audit_krule_to_data(&e->rule);
1282 if (unlikely(!data))
1283 break;
1284 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1285 data, sizeof(*data) + data->buflen);
1286 if (skb)
1287 skb_queue_tail(q, skb);
1288 kfree(data);
1289 }
1290 }
1291 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1292 if (skb)
1293 skb_queue_tail(q, skb);
1294 }
1295
1296 /* Log rule additions and removals */
1297 static void audit_log_rule_change(uid_t loginuid, u32 sid, char *action,
1298 struct audit_krule *rule, int res)
1299 {
1300 struct audit_buffer *ab;
1301
1302 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1303 if (!ab)
1304 return;
1305 audit_log_format(ab, "auid=%u", loginuid);
1306 if (sid) {
1307 char *ctx = NULL;
1308 u32 len;
1309 if (selinux_ctxid_to_string(sid, &ctx, &len))
1310 audit_log_format(ab, " ssid=%u", sid);
1311 else
1312 audit_log_format(ab, " subj=%s", ctx);
1313 kfree(ctx);
1314 }
1315 audit_log_format(ab, " %s rule key=", action);
1316 if (rule->filterkey)
1317 audit_log_untrustedstring(ab, rule->filterkey);
1318 else
1319 audit_log_format(ab, "(null)");
1320 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1321 audit_log_end(ab);
1322 }
1323
1324 /**
1325 * audit_receive_filter - apply all rules to the specified message type
1326 * @type: audit message type
1327 * @pid: target pid for netlink audit messages
1328 * @uid: target uid for netlink audit messages
1329 * @seq: netlink audit message sequence (serial) number
1330 * @data: payload data
1331 * @datasz: size of payload data
1332 * @loginuid: loginuid of sender
1333 * @sid: SE Linux Security ID of sender
1334 */
1335 int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
1336 size_t datasz, uid_t loginuid, u32 sid)
1337 {
1338 struct task_struct *tsk;
1339 struct audit_netlink_list *dest;
1340 int err = 0;
1341 struct audit_entry *entry;
1342
1343 switch (type) {
1344 case AUDIT_LIST:
1345 case AUDIT_LIST_RULES:
1346 /* We can't just spew out the rules here because we might fill
1347 * the available socket buffer space and deadlock waiting for
1348 * auditctl to read from it... which isn't ever going to
1349 * happen if we're actually running in the context of auditctl
1350 * trying to _send_ the stuff */
1351
1352 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1353 if (!dest)
1354 return -ENOMEM;
1355 dest->pid = pid;
1356 skb_queue_head_init(&dest->q);
1357
1358 mutex_lock(&audit_filter_mutex);
1359 if (type == AUDIT_LIST)
1360 audit_list(pid, seq, &dest->q);
1361 else
1362 audit_list_rules(pid, seq, &dest->q);
1363 mutex_unlock(&audit_filter_mutex);
1364
1365 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1366 if (IS_ERR(tsk)) {
1367 skb_queue_purge(&dest->q);
1368 kfree(dest);
1369 err = PTR_ERR(tsk);
1370 }
1371 break;
1372 case AUDIT_ADD:
1373 case AUDIT_ADD_RULE:
1374 if (type == AUDIT_ADD)
1375 entry = audit_rule_to_entry(data);
1376 else
1377 entry = audit_data_to_entry(data, datasz);
1378 if (IS_ERR(entry))
1379 return PTR_ERR(entry);
1380
1381 err = audit_add_rule(entry,
1382 &audit_filter_list[entry->rule.listnr]);
1383 audit_log_rule_change(loginuid, sid, "add", &entry->rule, !err);
1384
1385 if (err)
1386 audit_free_rule(entry);
1387 break;
1388 case AUDIT_DEL:
1389 case AUDIT_DEL_RULE:
1390 if (type == AUDIT_DEL)
1391 entry = audit_rule_to_entry(data);
1392 else
1393 entry = audit_data_to_entry(data, datasz);
1394 if (IS_ERR(entry))
1395 return PTR_ERR(entry);
1396
1397 err = audit_del_rule(entry,
1398 &audit_filter_list[entry->rule.listnr]);
1399 audit_log_rule_change(loginuid, sid, "remove", &entry->rule,
1400 !err);
1401
1402 audit_free_rule(entry);
1403 break;
1404 default:
1405 return -EINVAL;
1406 }
1407
1408 return err;
1409 }
1410
1411 int audit_comparator(const u32 left, const u32 op, const u32 right)
1412 {
1413 switch (op) {
1414 case AUDIT_EQUAL:
1415 return (left == right);
1416 case AUDIT_NOT_EQUAL:
1417 return (left != right);
1418 case AUDIT_LESS_THAN:
1419 return (left < right);
1420 case AUDIT_LESS_THAN_OR_EQUAL:
1421 return (left <= right);
1422 case AUDIT_GREATER_THAN:
1423 return (left > right);
1424 case AUDIT_GREATER_THAN_OR_EQUAL:
1425 return (left >= right);
1426 }
1427 BUG();
1428 return 0;
1429 }
1430
1431 /* Compare given dentry name with last component in given path,
1432 * return of 0 indicates a match. */
1433 int audit_compare_dname_path(const char *dname, const char *path,
1434 int *dirlen)
1435 {
1436 int dlen, plen;
1437 const char *p;
1438
1439 if (!dname || !path)
1440 return 1;
1441
1442 dlen = strlen(dname);
1443 plen = strlen(path);
1444 if (plen < dlen)
1445 return 1;
1446
1447 /* disregard trailing slashes */
1448 p = path + plen - 1;
1449 while ((*p == '/') && (p > path))
1450 p--;
1451
1452 /* find last path component */
1453 p = p - dlen + 1;
1454 if (p < path)
1455 return 1;
1456 else if (p > path) {
1457 if (*--p != '/')
1458 return 1;
1459 else
1460 p++;
1461 }
1462
1463 /* return length of path's directory component */
1464 if (dirlen)
1465 *dirlen = p - path;
1466 return strncmp(p, dname, dlen);
1467 }
1468
1469 static int audit_filter_user_rules(struct netlink_skb_parms *cb,
1470 struct audit_krule *rule,
1471 enum audit_state *state)
1472 {
1473 int i;
1474
1475 for (i = 0; i < rule->field_count; i++) {
1476 struct audit_field *f = &rule->fields[i];
1477 int result = 0;
1478
1479 switch (f->type) {
1480 case AUDIT_PID:
1481 result = audit_comparator(cb->creds.pid, f->op, f->val);
1482 break;
1483 case AUDIT_UID:
1484 result = audit_comparator(cb->creds.uid, f->op, f->val);
1485 break;
1486 case AUDIT_GID:
1487 result = audit_comparator(cb->creds.gid, f->op, f->val);
1488 break;
1489 case AUDIT_LOGINUID:
1490 result = audit_comparator(cb->loginuid, f->op, f->val);
1491 break;
1492 }
1493
1494 if (!result)
1495 return 0;
1496 }
1497 switch (rule->action) {
1498 case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
1499 case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
1500 }
1501 return 1;
1502 }
1503
1504 int audit_filter_user(struct netlink_skb_parms *cb, int type)
1505 {
1506 struct audit_entry *e;
1507 enum audit_state state;
1508 int ret = 1;
1509
1510 rcu_read_lock();
1511 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1512 if (audit_filter_user_rules(cb, &e->rule, &state)) {
1513 if (state == AUDIT_DISABLED)
1514 ret = 0;
1515 break;
1516 }
1517 }
1518 rcu_read_unlock();
1519
1520 return ret; /* Audit by default */
1521 }
1522
1523 int audit_filter_type(int type)
1524 {
1525 struct audit_entry *e;
1526 int result = 0;
1527
1528 rcu_read_lock();
1529 if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1530 goto unlock_and_return;
1531
1532 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1533 list) {
1534 int i;
1535 for (i = 0; i < e->rule.field_count; i++) {
1536 struct audit_field *f = &e->rule.fields[i];
1537 if (f->type == AUDIT_MSGTYPE) {
1538 result = audit_comparator(type, f->op, f->val);
1539 if (!result)
1540 break;
1541 }
1542 }
1543 if (result)
1544 goto unlock_and_return;
1545 }
1546 unlock_and_return:
1547 rcu_read_unlock();
1548 return result;
1549 }
1550
1551 /* Check to see if the rule contains any selinux fields. Returns 1 if there
1552 are selinux fields specified in the rule, 0 otherwise. */
1553 static inline int audit_rule_has_selinux(struct audit_krule *rule)
1554 {
1555 int i;
1556
1557 for (i = 0; i < rule->field_count; i++) {
1558 struct audit_field *f = &rule->fields[i];
1559 switch (f->type) {
1560 case AUDIT_SUBJ_USER:
1561 case AUDIT_SUBJ_ROLE:
1562 case AUDIT_SUBJ_TYPE:
1563 case AUDIT_SUBJ_SEN:
1564 case AUDIT_SUBJ_CLR:
1565 case AUDIT_OBJ_USER:
1566 case AUDIT_OBJ_ROLE:
1567 case AUDIT_OBJ_TYPE:
1568 case AUDIT_OBJ_LEV_LOW:
1569 case AUDIT_OBJ_LEV_HIGH:
1570 return 1;
1571 }
1572 }
1573
1574 return 0;
1575 }
1576
1577 /* This function will re-initialize the se_rule field of all applicable rules.
1578 * It will traverse the filter lists serarching for rules that contain selinux
1579 * specific filter fields. When such a rule is found, it is copied, the
1580 * selinux field is re-initialized, and the old rule is replaced with the
1581 * updated rule. */
1582 int selinux_audit_rule_update(void)
1583 {
1584 struct audit_entry *entry, *n, *nentry;
1585 struct audit_watch *watch;
1586 int i, err = 0;
1587
1588 /* audit_filter_mutex synchronizes the writers */
1589 mutex_lock(&audit_filter_mutex);
1590
1591 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1592 list_for_each_entry_safe(entry, n, &audit_filter_list[i], list) {
1593 if (!audit_rule_has_selinux(&entry->rule))
1594 continue;
1595
1596 watch = entry->rule.watch;
1597 nentry = audit_dupe_rule(&entry->rule, watch);
1598 if (unlikely(IS_ERR(nentry))) {
1599 /* save the first error encountered for the
1600 * return value */
1601 if (!err)
1602 err = PTR_ERR(nentry);
1603 audit_panic("error updating selinux filters");
1604 if (watch)
1605 list_del(&entry->rule.rlist);
1606 list_del_rcu(&entry->list);
1607 } else {
1608 if (watch) {
1609 list_add(&nentry->rule.rlist,
1610 &watch->rules);
1611 list_del(&entry->rule.rlist);
1612 }
1613 list_replace_rcu(&entry->list, &nentry->list);
1614 }
1615 call_rcu(&entry->rcu, audit_free_rule_rcu);
1616 }
1617 }
1618
1619 mutex_unlock(&audit_filter_mutex);
1620
1621 return err;
1622 }
1623
1624 /* Update watch data in audit rules based on inotify events. */
1625 void audit_handle_ievent(struct inotify_watch *i_watch, u32 wd, u32 mask,
1626 u32 cookie, const char *dname, struct inode *inode)
1627 {
1628 struct audit_parent *parent;
1629
1630 parent = container_of(i_watch, struct audit_parent, wdata);
1631
1632 if (mask & (IN_CREATE|IN_MOVED_TO) && inode)
1633 audit_update_watch(parent, dname, inode->i_sb->s_dev,
1634 inode->i_ino, 0);
1635 else if (mask & (IN_DELETE|IN_MOVED_FROM))
1636 audit_update_watch(parent, dname, (dev_t)-1, (unsigned long)-1, 1);
1637 /* inotify automatically removes the watch and sends IN_IGNORED */
1638 else if (mask & (IN_DELETE_SELF|IN_UNMOUNT))
1639 audit_remove_parent_watches(parent);
1640 /* inotify does not remove the watch, so remove it manually */
1641 else if(mask & IN_MOVE_SELF) {
1642 audit_remove_parent_watches(parent);
1643 inotify_remove_watch_locked(audit_ih, i_watch);
1644 } else if (mask & IN_IGNORED)
1645 put_inotify_watch(i_watch);
1646 }
Linux kernel - Deliverables
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