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Linux 2.6.19-rc6
[cris-mirror.git] / kernel / auditfilter.c
blob4f40d923af8ea2a349736c793d2164c72aa4fa63
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 * sizeof(__u32)))
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 /* Common user-space to kernel rule translation. */
315 static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule)
316 {
317 unsigned listnr;
318 struct audit_entry *entry;
319 int i, err;
320
321 err = -EINVAL;
322 listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
323 switch(listnr) {
324 default:
325 goto exit_err;
326 case AUDIT_FILTER_USER:
327 case AUDIT_FILTER_TYPE:
328 #ifdef CONFIG_AUDITSYSCALL
329 case AUDIT_FILTER_ENTRY:
330 case AUDIT_FILTER_EXIT:
331 case AUDIT_FILTER_TASK:
332 #endif
333 ;
334 }
335 if (unlikely(rule->action == AUDIT_POSSIBLE)) {
336 printk(KERN_ERR "AUDIT_POSSIBLE is deprecated\n");
337 goto exit_err;
338 }
339 if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
340 goto exit_err;
341 if (rule->field_count > AUDIT_MAX_FIELDS)
342 goto exit_err;
343
344 err = -ENOMEM;
345 entry = audit_init_entry(rule->field_count);
346 if (!entry)
347 goto exit_err;
348
349 entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
350 entry->rule.listnr = listnr;
351 entry->rule.action = rule->action;
352 entry->rule.field_count = rule->field_count;
353
354 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
355 entry->rule.mask[i] = rule->mask[i];
356
357 for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
358 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
359 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
360 __u32 *class;
361
362 if (!(*p & AUDIT_BIT(bit)))
363 continue;
364 *p &= ~AUDIT_BIT(bit);
365 class = classes[i];
366 if (class) {
367 int j;
368 for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
369 entry->rule.mask[j] |= class[j];
370 }
371 }
372
373 return entry;
374
375 exit_err:
376 return ERR_PTR(err);
377 }
378
379 /* Translate struct audit_rule to kernel's rule respresentation.
380 * Exists for backward compatibility with userspace. */
381 static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
382 {
383 struct audit_entry *entry;
384 struct audit_field *f;
385 int err = 0;
386 int i;
387
388 entry = audit_to_entry_common(rule);
389 if (IS_ERR(entry))
390 goto exit_nofree;
391
392 for (i = 0; i < rule->field_count; i++) {
393 struct audit_field *f = &entry->rule.fields[i];
394
395 f->op = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS);
396 f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS);
397 f->val = rule->values[i];
398
399 err = -EINVAL;
400 switch(f->type) {
401 default:
402 goto exit_free;
403 case AUDIT_PID:
404 case AUDIT_UID:
405 case AUDIT_EUID:
406 case AUDIT_SUID:
407 case AUDIT_FSUID:
408 case AUDIT_GID:
409 case AUDIT_EGID:
410 case AUDIT_SGID:
411 case AUDIT_FSGID:
412 case AUDIT_LOGINUID:
413 case AUDIT_PERS:
414 case AUDIT_MSGTYPE:
415 case AUDIT_PPID:
416 case AUDIT_DEVMAJOR:
417 case AUDIT_DEVMINOR:
418 case AUDIT_EXIT:
419 case AUDIT_SUCCESS:
420 case AUDIT_ARG0:
421 case AUDIT_ARG1:
422 case AUDIT_ARG2:
423 case AUDIT_ARG3:
424 break;
425 /* arch is only allowed to be = or != */
426 case AUDIT_ARCH:
427 if ((f->op != AUDIT_NOT_EQUAL) && (f->op != AUDIT_EQUAL)
428 && (f->op != AUDIT_NEGATE) && (f->op)) {
429 err = -EINVAL;
430 goto exit_free;
431 }
432 break;
433 case AUDIT_PERM:
434 if (f->val & ~15)
435 goto exit_free;
436 break;
437 case AUDIT_INODE:
438 err = audit_to_inode(&entry->rule, f);
439 if (err)
440 goto exit_free;
441 break;
442 }
443
444 entry->rule.vers_ops = (f->op & AUDIT_OPERATORS) ? 2 : 1;
445
446 /* Support for legacy operators where
447 * AUDIT_NEGATE bit signifies != and otherwise assumes == */
448 if (f->op & AUDIT_NEGATE)
449 f->op = AUDIT_NOT_EQUAL;
450 else if (!f->op)
451 f->op = AUDIT_EQUAL;
452 else if (f->op == AUDIT_OPERATORS) {
453 err = -EINVAL;
454 goto exit_free;
455 }
456 }
457
458 f = entry->rule.inode_f;
459 if (f) {
460 switch(f->op) {
461 case AUDIT_NOT_EQUAL:
462 entry->rule.inode_f = NULL;
463 case AUDIT_EQUAL:
464 break;
465 default:
466 err = -EINVAL;
467 goto exit_free;
468 }
469 }
470
471 exit_nofree:
472 return entry;
473
474 exit_free:
475 audit_free_rule(entry);
476 return ERR_PTR(err);
477 }
478
479 /* Translate struct audit_rule_data to kernel's rule respresentation. */
480 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
481 size_t datasz)
482 {
483 int err = 0;
484 struct audit_entry *entry;
485 struct audit_field *f;
486 void *bufp;
487 size_t remain = datasz - sizeof(struct audit_rule_data);
488 int i;
489 char *str;
490
491 entry = audit_to_entry_common((struct audit_rule *)data);
492 if (IS_ERR(entry))
493 goto exit_nofree;
494
495 bufp = data->buf;
496 entry->rule.vers_ops = 2;
497 for (i = 0; i < data->field_count; i++) {
498 struct audit_field *f = &entry->rule.fields[i];
499
500 err = -EINVAL;
501 if (!(data->fieldflags[i] & AUDIT_OPERATORS) ||
502 data->fieldflags[i] & ~AUDIT_OPERATORS)
503 goto exit_free;
504
505 f->op = data->fieldflags[i] & AUDIT_OPERATORS;
506 f->type = data->fields[i];
507 f->val = data->values[i];
508 f->se_str = NULL;
509 f->se_rule = NULL;
510 switch(f->type) {
511 case AUDIT_PID:
512 case AUDIT_UID:
513 case AUDIT_EUID:
514 case AUDIT_SUID:
515 case AUDIT_FSUID:
516 case AUDIT_GID:
517 case AUDIT_EGID:
518 case AUDIT_SGID:
519 case AUDIT_FSGID:
520 case AUDIT_LOGINUID:
521 case AUDIT_PERS:
522 case AUDIT_ARCH:
523 case AUDIT_MSGTYPE:
524 case AUDIT_PPID:
525 case AUDIT_DEVMAJOR:
526 case AUDIT_DEVMINOR:
527 case AUDIT_EXIT:
528 case AUDIT_SUCCESS:
529 case AUDIT_ARG0:
530 case AUDIT_ARG1:
531 case AUDIT_ARG2:
532 case AUDIT_ARG3:
533 break;
534 case AUDIT_SUBJ_USER:
535 case AUDIT_SUBJ_ROLE:
536 case AUDIT_SUBJ_TYPE:
537 case AUDIT_SUBJ_SEN:
538 case AUDIT_SUBJ_CLR:
539 case AUDIT_OBJ_USER:
540 case AUDIT_OBJ_ROLE:
541 case AUDIT_OBJ_TYPE:
542 case AUDIT_OBJ_LEV_LOW:
543 case AUDIT_OBJ_LEV_HIGH:
544 str = audit_unpack_string(&bufp, &remain, f->val);
545 if (IS_ERR(str))
546 goto exit_free;
547 entry->rule.buflen += f->val;
548
549 err = selinux_audit_rule_init(f->type, f->op, str,
550 &f->se_rule);
551 /* Keep currently invalid fields around in case they
552 * become valid after a policy reload. */
553 if (err == -EINVAL) {
554 printk(KERN_WARNING "audit rule for selinux "
555 "\'%s\' is invalid\n", str);
556 err = 0;
557 }
558 if (err) {
559 kfree(str);
560 goto exit_free;
561 } else
562 f->se_str = str;
563 break;
564 case AUDIT_WATCH:
565 str = audit_unpack_string(&bufp, &remain, f->val);
566 if (IS_ERR(str))
567 goto exit_free;
568 entry->rule.buflen += f->val;
569
570 err = audit_to_watch(&entry->rule, str, f->val, f->op);
571 if (err) {
572 kfree(str);
573 goto exit_free;
574 }
575 break;
576 case AUDIT_INODE:
577 err = audit_to_inode(&entry->rule, f);
578 if (err)
579 goto exit_free;
580 break;
581 case AUDIT_FILTERKEY:
582 err = -EINVAL;
583 if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
584 goto exit_free;
585 str = audit_unpack_string(&bufp, &remain, f->val);
586 if (IS_ERR(str))
587 goto exit_free;
588 entry->rule.buflen += f->val;
589 entry->rule.filterkey = str;
590 break;
591 case AUDIT_PERM:
592 if (f->val & ~15)
593 goto exit_free;
594 break;
595 default:
596 goto exit_free;
597 }
598 }
599
600 f = entry->rule.inode_f;
601 if (f) {
602 switch(f->op) {
603 case AUDIT_NOT_EQUAL:
604 entry->rule.inode_f = NULL;
605 case AUDIT_EQUAL:
606 break;
607 default:
608 err = -EINVAL;
609 goto exit_free;
610 }
611 }
612
613 exit_nofree:
614 return entry;
615
616 exit_free:
617 audit_free_rule(entry);
618 return ERR_PTR(err);
619 }
620
621 /* Pack a filter field's string representation into data block. */
622 static inline size_t audit_pack_string(void **bufp, char *str)
623 {
624 size_t len = strlen(str);
625
626 memcpy(*bufp, str, len);
627 *bufp += len;
628
629 return len;
630 }
631
632 /* Translate kernel rule respresentation to struct audit_rule.
633 * Exists for backward compatibility with userspace. */
634 static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
635 {
636 struct audit_rule *rule;
637 int i;
638
639 rule = kmalloc(sizeof(*rule), GFP_KERNEL);
640 if (unlikely(!rule))
641 return NULL;
642 memset(rule, 0, sizeof(*rule));
643
644 rule->flags = krule->flags | krule->listnr;
645 rule->action = krule->action;
646 rule->field_count = krule->field_count;
647 for (i = 0; i < rule->field_count; i++) {
648 rule->values[i] = krule->fields[i].val;
649 rule->fields[i] = krule->fields[i].type;
650
651 if (krule->vers_ops == 1) {
652 if (krule->fields[i].op & AUDIT_NOT_EQUAL)
653 rule->fields[i] |= AUDIT_NEGATE;
654 } else {
655 rule->fields[i] |= krule->fields[i].op;
656 }
657 }
658 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
659
660 return rule;
661 }
662
663 /* Translate kernel rule respresentation to struct audit_rule_data. */
664 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
665 {
666 struct audit_rule_data *data;
667 void *bufp;
668 int i;
669
670 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
671 if (unlikely(!data))
672 return NULL;
673 memset(data, 0, sizeof(*data));
674
675 data->flags = krule->flags | krule->listnr;
676 data->action = krule->action;
677 data->field_count = krule->field_count;
678 bufp = data->buf;
679 for (i = 0; i < data->field_count; i++) {
680 struct audit_field *f = &krule->fields[i];
681
682 data->fields[i] = f->type;
683 data->fieldflags[i] = f->op;
684 switch(f->type) {
685 case AUDIT_SUBJ_USER:
686 case AUDIT_SUBJ_ROLE:
687 case AUDIT_SUBJ_TYPE:
688 case AUDIT_SUBJ_SEN:
689 case AUDIT_SUBJ_CLR:
690 case AUDIT_OBJ_USER:
691 case AUDIT_OBJ_ROLE:
692 case AUDIT_OBJ_TYPE:
693 case AUDIT_OBJ_LEV_LOW:
694 case AUDIT_OBJ_LEV_HIGH:
695 data->buflen += data->values[i] =
696 audit_pack_string(&bufp, f->se_str);
697 break;
698 case AUDIT_WATCH:
699 data->buflen += data->values[i] =
700 audit_pack_string(&bufp, krule->watch->path);
701 break;
702 case AUDIT_FILTERKEY:
703 data->buflen += data->values[i] =
704 audit_pack_string(&bufp, krule->filterkey);
705 break;
706 default:
707 data->values[i] = f->val;
708 }
709 }
710 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
711
712 return data;
713 }
714
715 /* Compare two rules in kernel format. Considered success if rules
716 * don't match. */
717 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
718 {
719 int i;
720
721 if (a->flags != b->flags ||
722 a->listnr != b->listnr ||
723 a->action != b->action ||
724 a->field_count != b->field_count)
725 return 1;
726
727 for (i = 0; i < a->field_count; i++) {
728 if (a->fields[i].type != b->fields[i].type ||
729 a->fields[i].op != b->fields[i].op)
730 return 1;
731
732 switch(a->fields[i].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 if (strcmp(a->fields[i].se_str, b->fields[i].se_str))
744 return 1;
745 break;
746 case AUDIT_WATCH:
747 if (strcmp(a->watch->path, b->watch->path))
748 return 1;
749 break;
750 case AUDIT_FILTERKEY:
751 /* both filterkeys exist based on above type compare */
752 if (strcmp(a->filterkey, b->filterkey))
753 return 1;
754 break;
755 default:
756 if (a->fields[i].val != b->fields[i].val)
757 return 1;
758 }
759 }
760
761 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
762 if (a->mask[i] != b->mask[i])
763 return 1;
764
765 return 0;
766 }
767
768 /* Duplicate the given audit watch. The new watch's rules list is initialized
769 * to an empty list and wlist is undefined. */
770 static struct audit_watch *audit_dupe_watch(struct audit_watch *old)
771 {
772 char *path;
773 struct audit_watch *new;
774
775 path = kstrdup(old->path, GFP_KERNEL);
776 if (unlikely(!path))
777 return ERR_PTR(-ENOMEM);
778
779 new = audit_init_watch(path);
780 if (unlikely(IS_ERR(new))) {
781 kfree(path);
782 goto out;
783 }
784
785 new->dev = old->dev;
786 new->ino = old->ino;
787 get_inotify_watch(&old->parent->wdata);
788 new->parent = old->parent;
789
790 out:
791 return new;
792 }
793
794 /* Duplicate selinux field information. The se_rule is opaque, so must be
795 * re-initialized. */
796 static inline int audit_dupe_selinux_field(struct audit_field *df,
797 struct audit_field *sf)
798 {
799 int ret = 0;
800 char *se_str;
801
802 /* our own copy of se_str */
803 se_str = kstrdup(sf->se_str, GFP_KERNEL);
804 if (unlikely(IS_ERR(se_str)))
805 return -ENOMEM;
806 df->se_str = se_str;
807
808 /* our own (refreshed) copy of se_rule */
809 ret = selinux_audit_rule_init(df->type, df->op, df->se_str,
810 &df->se_rule);
811 /* Keep currently invalid fields around in case they
812 * become valid after a policy reload. */
813 if (ret == -EINVAL) {
814 printk(KERN_WARNING "audit rule for selinux \'%s\' is "
815 "invalid\n", df->se_str);
816 ret = 0;
817 }
818
819 return ret;
820 }
821
822 /* Duplicate an audit rule. This will be a deep copy with the exception
823 * of the watch - that pointer is carried over. The selinux specific fields
824 * will be updated in the copy. The point is to be able to replace the old
825 * rule with the new rule in the filterlist, then free the old rule.
826 * The rlist element is undefined; list manipulations are handled apart from
827 * the initial copy. */
828 static struct audit_entry *audit_dupe_rule(struct audit_krule *old,
829 struct audit_watch *watch)
830 {
831 u32 fcount = old->field_count;
832 struct audit_entry *entry;
833 struct audit_krule *new;
834 char *fk;
835 int i, err = 0;
836
837 entry = audit_init_entry(fcount);
838 if (unlikely(!entry))
839 return ERR_PTR(-ENOMEM);
840
841 new = &entry->rule;
842 new->vers_ops = old->vers_ops;
843 new->flags = old->flags;
844 new->listnr = old->listnr;
845 new->action = old->action;
846 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
847 new->mask[i] = old->mask[i];
848 new->buflen = old->buflen;
849 new->inode_f = old->inode_f;
850 new->watch = NULL;
851 new->field_count = old->field_count;
852 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
853
854 /* deep copy this information, updating the se_rule fields, because
855 * the originals will all be freed when the old rule is freed. */
856 for (i = 0; i < fcount; i++) {
857 switch (new->fields[i].type) {
858 case AUDIT_SUBJ_USER:
859 case AUDIT_SUBJ_ROLE:
860 case AUDIT_SUBJ_TYPE:
861 case AUDIT_SUBJ_SEN:
862 case AUDIT_SUBJ_CLR:
863 case AUDIT_OBJ_USER:
864 case AUDIT_OBJ_ROLE:
865 case AUDIT_OBJ_TYPE:
866 case AUDIT_OBJ_LEV_LOW:
867 case AUDIT_OBJ_LEV_HIGH:
868 err = audit_dupe_selinux_field(&new->fields[i],
869 &old->fields[i]);
870 break;
871 case AUDIT_FILTERKEY:
872 fk = kstrdup(old->filterkey, GFP_KERNEL);
873 if (unlikely(!fk))
874 err = -ENOMEM;
875 else
876 new->filterkey = fk;
877 }
878 if (err) {
879 audit_free_rule(entry);
880 return ERR_PTR(err);
881 }
882 }
883
884 if (watch) {
885 audit_get_watch(watch);
886 new->watch = watch;
887 }
888
889 return entry;
890 }
891
892 /* Update inode info in audit rules based on filesystem event. */
893 static void audit_update_watch(struct audit_parent *parent,
894 const char *dname, dev_t dev,
895 unsigned long ino, unsigned invalidating)
896 {
897 struct audit_watch *owatch, *nwatch, *nextw;
898 struct audit_krule *r, *nextr;
899 struct audit_entry *oentry, *nentry;
900 struct audit_buffer *ab;
901
902 mutex_lock(&audit_filter_mutex);
903 list_for_each_entry_safe(owatch, nextw, &parent->watches, wlist) {
904 if (audit_compare_dname_path(dname, owatch->path, NULL))
905 continue;
906
907 /* If the update involves invalidating rules, do the inode-based
908 * filtering now, so we don't omit records. */
909 if (invalidating &&
910 audit_filter_inodes(current, current->audit_context) == AUDIT_RECORD_CONTEXT)
911 audit_set_auditable(current->audit_context);
912
913 nwatch = audit_dupe_watch(owatch);
914 if (unlikely(IS_ERR(nwatch))) {
915 mutex_unlock(&audit_filter_mutex);
916 audit_panic("error updating watch, skipping");
917 return;
918 }
919 nwatch->dev = dev;
920 nwatch->ino = ino;
921
922 list_for_each_entry_safe(r, nextr, &owatch->rules, rlist) {
923
924 oentry = container_of(r, struct audit_entry, rule);
925 list_del(&oentry->rule.rlist);
926 list_del_rcu(&oentry->list);
927
928 nentry = audit_dupe_rule(&oentry->rule, nwatch);
929 if (unlikely(IS_ERR(nentry)))
930 audit_panic("error updating watch, removing");
931 else {
932 int h = audit_hash_ino((u32)ino);
933 list_add(&nentry->rule.rlist, &nwatch->rules);
934 list_add_rcu(&nentry->list, &audit_inode_hash[h]);
935 }
936
937 call_rcu(&oentry->rcu, audit_free_rule_rcu);
938 }
939
940 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
941 audit_log_format(ab, "audit updated rules specifying path=");
942 audit_log_untrustedstring(ab, owatch->path);
943 audit_log_format(ab, " with dev=%u ino=%lu\n", dev, ino);
944 audit_log_end(ab);
945
946 audit_remove_watch(owatch);
947 goto add_watch_to_parent; /* event applies to a single watch */
948 }
949 mutex_unlock(&audit_filter_mutex);
950 return;
951
952 add_watch_to_parent:
953 list_add(&nwatch->wlist, &parent->watches);
954 mutex_unlock(&audit_filter_mutex);
955 return;
956 }
957
958 /* Remove all watches & rules associated with a parent that is going away. */
959 static void audit_remove_parent_watches(struct audit_parent *parent)
960 {
961 struct audit_watch *w, *nextw;
962 struct audit_krule *r, *nextr;
963 struct audit_entry *e;
964 struct audit_buffer *ab;
965
966 mutex_lock(&audit_filter_mutex);
967 parent->flags |= AUDIT_PARENT_INVALID;
968 list_for_each_entry_safe(w, nextw, &parent->watches, wlist) {
969 list_for_each_entry_safe(r, nextr, &w->rules, rlist) {
970 e = container_of(r, struct audit_entry, rule);
971
972 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
973 audit_log_format(ab, "audit implicitly removed rule path=");
974 audit_log_untrustedstring(ab, w->path);
975 if (r->filterkey) {
976 audit_log_format(ab, " key=");
977 audit_log_untrustedstring(ab, r->filterkey);
978 } else
979 audit_log_format(ab, " key=(null)");
980 audit_log_format(ab, " list=%d", r->listnr);
981 audit_log_end(ab);
982
983 list_del(&r->rlist);
984 list_del_rcu(&e->list);
985 call_rcu(&e->rcu, audit_free_rule_rcu);
986 }
987 audit_remove_watch(w);
988 }
989 mutex_unlock(&audit_filter_mutex);
990 }
991
992 /* Unregister inotify watches for parents on in_list.
993 * Generates an IN_IGNORED event. */
994 static void audit_inotify_unregister(struct list_head *in_list)
995 {
996 struct audit_parent *p, *n;
997
998 list_for_each_entry_safe(p, n, in_list, ilist) {
999 list_del(&p->ilist);
1000 inotify_rm_watch(audit_ih, &p->wdata);
1001 /* the put matching the get in audit_do_del_rule() */
1002 put_inotify_watch(&p->wdata);
1003 }
1004 }
1005
1006 /* Find an existing audit rule.
1007 * Caller must hold audit_filter_mutex to prevent stale rule data. */
1008 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
1009 struct list_head *list)
1010 {
1011 struct audit_entry *e, *found = NULL;
1012 int h;
1013
1014 if (entry->rule.watch) {
1015 /* we don't know the inode number, so must walk entire hash */
1016 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
1017 list = &audit_inode_hash[h];
1018 list_for_each_entry(e, list, list)
1019 if (!audit_compare_rule(&entry->rule, &e->rule)) {
1020 found = e;
1021 goto out;
1022 }
1023 }
1024 goto out;
1025 }
1026
1027 list_for_each_entry(e, list, list)
1028 if (!audit_compare_rule(&entry->rule, &e->rule)) {
1029 found = e;
1030 goto out;
1031 }
1032
1033 out:
1034 return found;
1035 }
1036
1037 /* Get path information necessary for adding watches. */
1038 static int audit_get_nd(char *path, struct nameidata **ndp,
1039 struct nameidata **ndw)
1040 {
1041 struct nameidata *ndparent, *ndwatch;
1042 int err;
1043
1044 ndparent = kmalloc(sizeof(*ndparent), GFP_KERNEL);
1045 if (unlikely(!ndparent))
1046 return -ENOMEM;
1047
1048 ndwatch = kmalloc(sizeof(*ndwatch), GFP_KERNEL);
1049 if (unlikely(!ndwatch)) {
1050 kfree(ndparent);
1051 return -ENOMEM;
1052 }
1053
1054 err = path_lookup(path, LOOKUP_PARENT, ndparent);
1055 if (err) {
1056 kfree(ndparent);
1057 kfree(ndwatch);
1058 return err;
1059 }
1060
1061 err = path_lookup(path, 0, ndwatch);
1062 if (err) {
1063 kfree(ndwatch);
1064 ndwatch = NULL;
1065 }
1066
1067 *ndp = ndparent;
1068 *ndw = ndwatch;
1069
1070 return 0;
1071 }
1072
1073 /* Release resources used for watch path information. */
1074 static void audit_put_nd(struct nameidata *ndp, struct nameidata *ndw)
1075 {
1076 if (ndp) {
1077 path_release(ndp);
1078 kfree(ndp);
1079 }
1080 if (ndw) {
1081 path_release(ndw);
1082 kfree(ndw);
1083 }
1084 }
1085
1086 /* Associate the given rule with an existing parent inotify_watch.
1087 * Caller must hold audit_filter_mutex. */
1088 static void audit_add_to_parent(struct audit_krule *krule,
1089 struct audit_parent *parent)
1090 {
1091 struct audit_watch *w, *watch = krule->watch;
1092 int watch_found = 0;
1093
1094 list_for_each_entry(w, &parent->watches, wlist) {
1095 if (strcmp(watch->path, w->path))
1096 continue;
1097
1098 watch_found = 1;
1099
1100 /* put krule's and initial refs to temporary watch */
1101 audit_put_watch(watch);
1102 audit_put_watch(watch);
1103
1104 audit_get_watch(w);
1105 krule->watch = watch = w;
1106 break;
1107 }
1108
1109 if (!watch_found) {
1110 get_inotify_watch(&parent->wdata);
1111 watch->parent = parent;
1112
1113 list_add(&watch->wlist, &parent->watches);
1114 }
1115 list_add(&krule->rlist, &watch->rules);
1116 }
1117
1118 /* Find a matching watch entry, or add this one.
1119 * Caller must hold audit_filter_mutex. */
1120 static int audit_add_watch(struct audit_krule *krule, struct nameidata *ndp,
1121 struct nameidata *ndw)
1122 {
1123 struct audit_watch *watch = krule->watch;
1124 struct inotify_watch *i_watch;
1125 struct audit_parent *parent;
1126 int ret = 0;
1127
1128 /* update watch filter fields */
1129 if (ndw) {
1130 watch->dev = ndw->dentry->d_inode->i_sb->s_dev;
1131 watch->ino = ndw->dentry->d_inode->i_ino;
1132 }
1133
1134 /* The audit_filter_mutex must not be held during inotify calls because
1135 * we hold it during inotify event callback processing. If an existing
1136 * inotify watch is found, inotify_find_watch() grabs a reference before
1137 * returning.
1138 */
1139 mutex_unlock(&audit_filter_mutex);
1140
1141 if (inotify_find_watch(audit_ih, ndp->dentry->d_inode, &i_watch) < 0) {
1142 parent = audit_init_parent(ndp);
1143 if (IS_ERR(parent)) {
1144 /* caller expects mutex locked */
1145 mutex_lock(&audit_filter_mutex);
1146 return PTR_ERR(parent);
1147 }
1148 } else
1149 parent = container_of(i_watch, struct audit_parent, wdata);
1150
1151 mutex_lock(&audit_filter_mutex);
1152
1153 /* parent was moved before we took audit_filter_mutex */
1154 if (parent->flags & AUDIT_PARENT_INVALID)
1155 ret = -ENOENT;
1156 else
1157 audit_add_to_parent(krule, parent);
1158
1159 /* match get in audit_init_parent or inotify_find_watch */
1160 put_inotify_watch(&parent->wdata);
1161 return ret;
1162 }
1163
1164 /* Add rule to given filterlist if not a duplicate. */
1165 static inline int audit_add_rule(struct audit_entry *entry,
1166 struct list_head *list)
1167 {
1168 struct audit_entry *e;
1169 struct audit_field *inode_f = entry->rule.inode_f;
1170 struct audit_watch *watch = entry->rule.watch;
1171 struct nameidata *ndp, *ndw;
1172 int h, err, putnd_needed = 0;
1173 #ifdef CONFIG_AUDITSYSCALL
1174 int dont_count = 0;
1175
1176 /* If either of these, don't count towards total */
1177 if (entry->rule.listnr == AUDIT_FILTER_USER ||
1178 entry->rule.listnr == AUDIT_FILTER_TYPE)
1179 dont_count = 1;
1180 #endif
1181
1182 if (inode_f) {
1183 h = audit_hash_ino(inode_f->val);
1184 list = &audit_inode_hash[h];
1185 }
1186
1187 mutex_lock(&audit_filter_mutex);
1188 e = audit_find_rule(entry, list);
1189 mutex_unlock(&audit_filter_mutex);
1190 if (e) {
1191 err = -EEXIST;
1192 goto error;
1193 }
1194
1195 /* Avoid calling path_lookup under audit_filter_mutex. */
1196 if (watch) {
1197 err = audit_get_nd(watch->path, &ndp, &ndw);
1198 if (err)
1199 goto error;
1200 putnd_needed = 1;
1201 }
1202
1203 mutex_lock(&audit_filter_mutex);
1204 if (watch) {
1205 /* audit_filter_mutex is dropped and re-taken during this call */
1206 err = audit_add_watch(&entry->rule, ndp, ndw);
1207 if (err) {
1208 mutex_unlock(&audit_filter_mutex);
1209 goto error;
1210 }
1211 h = audit_hash_ino((u32)watch->ino);
1212 list = &audit_inode_hash[h];
1213 }
1214
1215 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
1216 list_add_rcu(&entry->list, list);
1217 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
1218 } else {
1219 list_add_tail_rcu(&entry->list, list);
1220 }
1221 #ifdef CONFIG_AUDITSYSCALL
1222 if (!dont_count)
1223 audit_n_rules++;
1224 #endif
1225 mutex_unlock(&audit_filter_mutex);
1226
1227 if (putnd_needed)
1228 audit_put_nd(ndp, ndw);
1229
1230 return 0;
1231
1232 error:
1233 if (putnd_needed)
1234 audit_put_nd(ndp, ndw);
1235 if (watch)
1236 audit_put_watch(watch); /* tmp watch, matches initial get */
1237 return err;
1238 }
1239
1240 /* Remove an existing rule from filterlist. */
1241 static inline int audit_del_rule(struct audit_entry *entry,
1242 struct list_head *list)
1243 {
1244 struct audit_entry *e;
1245 struct audit_field *inode_f = entry->rule.inode_f;
1246 struct audit_watch *watch, *tmp_watch = entry->rule.watch;
1247 LIST_HEAD(inotify_list);
1248 int h, ret = 0;
1249 #ifdef CONFIG_AUDITSYSCALL
1250 int dont_count = 0;
1251
1252 /* If either of these, don't count towards total */
1253 if (entry->rule.listnr == AUDIT_FILTER_USER ||
1254 entry->rule.listnr == AUDIT_FILTER_TYPE)
1255 dont_count = 1;
1256 #endif
1257
1258 if (inode_f) {
1259 h = audit_hash_ino(inode_f->val);
1260 list = &audit_inode_hash[h];
1261 }
1262
1263 mutex_lock(&audit_filter_mutex);
1264 e = audit_find_rule(entry, list);
1265 if (!e) {
1266 mutex_unlock(&audit_filter_mutex);
1267 ret = -ENOENT;
1268 goto out;
1269 }
1270
1271 watch = e->rule.watch;
1272 if (watch) {
1273 struct audit_parent *parent = watch->parent;
1274
1275 list_del(&e->rule.rlist);
1276
1277 if (list_empty(&watch->rules)) {
1278 audit_remove_watch(watch);
1279
1280 if (list_empty(&parent->watches)) {
1281 /* Put parent on the inotify un-registration
1282 * list. Grab a reference before releasing
1283 * audit_filter_mutex, to be released in
1284 * audit_inotify_unregister(). */
1285 list_add(&parent->ilist, &inotify_list);
1286 get_inotify_watch(&parent->wdata);
1287 }
1288 }
1289 }
1290
1291 list_del_rcu(&e->list);
1292 call_rcu(&e->rcu, audit_free_rule_rcu);
1293
1294 #ifdef CONFIG_AUDITSYSCALL
1295 if (!dont_count)
1296 audit_n_rules--;
1297 #endif
1298 mutex_unlock(&audit_filter_mutex);
1299
1300 if (!list_empty(&inotify_list))
1301 audit_inotify_unregister(&inotify_list);
1302
1303 out:
1304 if (tmp_watch)
1305 audit_put_watch(tmp_watch); /* match initial get */
1306
1307 return ret;
1308 }
1309
1310 /* List rules using struct audit_rule. Exists for backward
1311 * compatibility with userspace. */
1312 static void audit_list(int pid, int seq, struct sk_buff_head *q)
1313 {
1314 struct sk_buff *skb;
1315 struct audit_entry *entry;
1316 int i;
1317
1318 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1319 * iterator to sync with list writers. */
1320 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1321 list_for_each_entry(entry, &audit_filter_list[i], list) {
1322 struct audit_rule *rule;
1323
1324 rule = audit_krule_to_rule(&entry->rule);
1325 if (unlikely(!rule))
1326 break;
1327 skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1328 rule, sizeof(*rule));
1329 if (skb)
1330 skb_queue_tail(q, skb);
1331 kfree(rule);
1332 }
1333 }
1334 for (i = 0; i < AUDIT_INODE_BUCKETS; i++) {
1335 list_for_each_entry(entry, &audit_inode_hash[i], list) {
1336 struct audit_rule *rule;
1337
1338 rule = audit_krule_to_rule(&entry->rule);
1339 if (unlikely(!rule))
1340 break;
1341 skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1342 rule, sizeof(*rule));
1343 if (skb)
1344 skb_queue_tail(q, skb);
1345 kfree(rule);
1346 }
1347 }
1348 skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
1349 if (skb)
1350 skb_queue_tail(q, skb);
1351 }
1352
1353 /* List rules using struct audit_rule_data. */
1354 static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
1355 {
1356 struct sk_buff *skb;
1357 struct audit_entry *e;
1358 int i;
1359
1360 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1361 * iterator to sync with list writers. */
1362 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1363 list_for_each_entry(e, &audit_filter_list[i], list) {
1364 struct audit_rule_data *data;
1365
1366 data = audit_krule_to_data(&e->rule);
1367 if (unlikely(!data))
1368 break;
1369 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1370 data, sizeof(*data) + data->buflen);
1371 if (skb)
1372 skb_queue_tail(q, skb);
1373 kfree(data);
1374 }
1375 }
1376 for (i=0; i< AUDIT_INODE_BUCKETS; i++) {
1377 list_for_each_entry(e, &audit_inode_hash[i], list) {
1378 struct audit_rule_data *data;
1379
1380 data = audit_krule_to_data(&e->rule);
1381 if (unlikely(!data))
1382 break;
1383 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1384 data, sizeof(*data) + data->buflen);
1385 if (skb)
1386 skb_queue_tail(q, skb);
1387 kfree(data);
1388 }
1389 }
1390 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1391 if (skb)
1392 skb_queue_tail(q, skb);
1393 }
1394
1395 /* Log rule additions and removals */
1396 static void audit_log_rule_change(uid_t loginuid, u32 sid, char *action,
1397 struct audit_krule *rule, int res)
1398 {
1399 struct audit_buffer *ab;
1400
1401 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1402 if (!ab)
1403 return;
1404 audit_log_format(ab, "auid=%u", loginuid);
1405 if (sid) {
1406 char *ctx = NULL;
1407 u32 len;
1408 if (selinux_sid_to_string(sid, &ctx, &len))
1409 audit_log_format(ab, " ssid=%u", sid);
1410 else
1411 audit_log_format(ab, " subj=%s", ctx);
1412 kfree(ctx);
1413 }
1414 audit_log_format(ab, " %s rule key=", action);
1415 if (rule->filterkey)
1416 audit_log_untrustedstring(ab, rule->filterkey);
1417 else
1418 audit_log_format(ab, "(null)");
1419 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1420 audit_log_end(ab);
1421 }
1422
1423 /**
1424 * audit_receive_filter - apply all rules to the specified message type
1425 * @type: audit message type
1426 * @pid: target pid for netlink audit messages
1427 * @uid: target uid for netlink audit messages
1428 * @seq: netlink audit message sequence (serial) number
1429 * @data: payload data
1430 * @datasz: size of payload data
1431 * @loginuid: loginuid of sender
1432 * @sid: SE Linux Security ID of sender
1433 */
1434 int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
1435 size_t datasz, uid_t loginuid, u32 sid)
1436 {
1437 struct task_struct *tsk;
1438 struct audit_netlink_list *dest;
1439 int err = 0;
1440 struct audit_entry *entry;
1441
1442 switch (type) {
1443 case AUDIT_LIST:
1444 case AUDIT_LIST_RULES:
1445 /* We can't just spew out the rules here because we might fill
1446 * the available socket buffer space and deadlock waiting for
1447 * auditctl to read from it... which isn't ever going to
1448 * happen if we're actually running in the context of auditctl
1449 * trying to _send_ the stuff */
1450
1451 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1452 if (!dest)
1453 return -ENOMEM;
1454 dest->pid = pid;
1455 skb_queue_head_init(&dest->q);
1456
1457 mutex_lock(&audit_filter_mutex);
1458 if (type == AUDIT_LIST)
1459 audit_list(pid, seq, &dest->q);
1460 else
1461 audit_list_rules(pid, seq, &dest->q);
1462 mutex_unlock(&audit_filter_mutex);
1463
1464 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1465 if (IS_ERR(tsk)) {
1466 skb_queue_purge(&dest->q);
1467 kfree(dest);
1468 err = PTR_ERR(tsk);
1469 }
1470 break;
1471 case AUDIT_ADD:
1472 case AUDIT_ADD_RULE:
1473 if (type == AUDIT_ADD)
1474 entry = audit_rule_to_entry(data);
1475 else
1476 entry = audit_data_to_entry(data, datasz);
1477 if (IS_ERR(entry))
1478 return PTR_ERR(entry);
1479
1480 err = audit_add_rule(entry,
1481 &audit_filter_list[entry->rule.listnr]);
1482 audit_log_rule_change(loginuid, sid, "add", &entry->rule, !err);
1483
1484 if (err)
1485 audit_free_rule(entry);
1486 break;
1487 case AUDIT_DEL:
1488 case AUDIT_DEL_RULE:
1489 if (type == AUDIT_DEL)
1490 entry = audit_rule_to_entry(data);
1491 else
1492 entry = audit_data_to_entry(data, datasz);
1493 if (IS_ERR(entry))
1494 return PTR_ERR(entry);
1495
1496 err = audit_del_rule(entry,
1497 &audit_filter_list[entry->rule.listnr]);
1498 audit_log_rule_change(loginuid, sid, "remove", &entry->rule,
1499 !err);
1500
1501 audit_free_rule(entry);
1502 break;
1503 default:
1504 return -EINVAL;
1505 }
1506
1507 return err;
1508 }
1509
1510 int audit_comparator(const u32 left, const u32 op, const u32 right)
1511 {
1512 switch (op) {
1513 case AUDIT_EQUAL:
1514 return (left == right);
1515 case AUDIT_NOT_EQUAL:
1516 return (left != right);
1517 case AUDIT_LESS_THAN:
1518 return (left < right);
1519 case AUDIT_LESS_THAN_OR_EQUAL:
1520 return (left <= right);
1521 case AUDIT_GREATER_THAN:
1522 return (left > right);
1523 case AUDIT_GREATER_THAN_OR_EQUAL:
1524 return (left >= right);
1525 }
1526 BUG();
1527 return 0;
1528 }
1529
1530 /* Compare given dentry name with last component in given path,
1531 * return of 0 indicates a match. */
1532 int audit_compare_dname_path(const char *dname, const char *path,
1533 int *dirlen)
1534 {
1535 int dlen, plen;
1536 const char *p;
1537
1538 if (!dname || !path)
1539 return 1;
1540
1541 dlen = strlen(dname);
1542 plen = strlen(path);
1543 if (plen < dlen)
1544 return 1;
1545
1546 /* disregard trailing slashes */
1547 p = path + plen - 1;
1548 while ((*p == '/') && (p > path))
1549 p--;
1550
1551 /* find last path component */
1552 p = p - dlen + 1;
1553 if (p < path)
1554 return 1;
1555 else if (p > path) {
1556 if (*--p != '/')
1557 return 1;
1558 else
1559 p++;
1560 }
1561
1562 /* return length of path's directory component */
1563 if (dirlen)
1564 *dirlen = p - path;
1565 return strncmp(p, dname, dlen);
1566 }
1567
1568 static int audit_filter_user_rules(struct netlink_skb_parms *cb,
1569 struct audit_krule *rule,
1570 enum audit_state *state)
1571 {
1572 int i;
1573
1574 for (i = 0; i < rule->field_count; i++) {
1575 struct audit_field *f = &rule->fields[i];
1576 int result = 0;
1577
1578 switch (f->type) {
1579 case AUDIT_PID:
1580 result = audit_comparator(cb->creds.pid, f->op, f->val);
1581 break;
1582 case AUDIT_UID:
1583 result = audit_comparator(cb->creds.uid, f->op, f->val);
1584 break;
1585 case AUDIT_GID:
1586 result = audit_comparator(cb->creds.gid, f->op, f->val);
1587 break;
1588 case AUDIT_LOGINUID:
1589 result = audit_comparator(cb->loginuid, f->op, f->val);
1590 break;
1591 }
1592
1593 if (!result)
1594 return 0;
1595 }
1596 switch (rule->action) {
1597 case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
1598 case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
1599 }
1600 return 1;
1601 }
1602
1603 int audit_filter_user(struct netlink_skb_parms *cb, int type)
1604 {
1605 struct audit_entry *e;
1606 enum audit_state state;
1607 int ret = 1;
1608
1609 rcu_read_lock();
1610 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1611 if (audit_filter_user_rules(cb, &e->rule, &state)) {
1612 if (state == AUDIT_DISABLED)
1613 ret = 0;
1614 break;
1615 }
1616 }
1617 rcu_read_unlock();
1618
1619 return ret; /* Audit by default */
1620 }
1621
1622 int audit_filter_type(int type)
1623 {
1624 struct audit_entry *e;
1625 int result = 0;
1626
1627 rcu_read_lock();
1628 if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1629 goto unlock_and_return;
1630
1631 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1632 list) {
1633 int i;
1634 for (i = 0; i < e->rule.field_count; i++) {
1635 struct audit_field *f = &e->rule.fields[i];
1636 if (f->type == AUDIT_MSGTYPE) {
1637 result = audit_comparator(type, f->op, f->val);
1638 if (!result)
1639 break;
1640 }
1641 }
1642 if (result)
1643 goto unlock_and_return;
1644 }
1645 unlock_and_return:
1646 rcu_read_unlock();
1647 return result;
1648 }
1649
1650 /* Check to see if the rule contains any selinux fields. Returns 1 if there
1651 are selinux fields specified in the rule, 0 otherwise. */
1652 static inline int audit_rule_has_selinux(struct audit_krule *rule)
1653 {
1654 int i;
1655
1656 for (i = 0; i < rule->field_count; i++) {
1657 struct audit_field *f = &rule->fields[i];
1658 switch (f->type) {
1659 case AUDIT_SUBJ_USER:
1660 case AUDIT_SUBJ_ROLE:
1661 case AUDIT_SUBJ_TYPE:
1662 case AUDIT_SUBJ_SEN:
1663 case AUDIT_SUBJ_CLR:
1664 case AUDIT_OBJ_USER:
1665 case AUDIT_OBJ_ROLE:
1666 case AUDIT_OBJ_TYPE:
1667 case AUDIT_OBJ_LEV_LOW:
1668 case AUDIT_OBJ_LEV_HIGH:
1669 return 1;
1670 }
1671 }
1672
1673 return 0;
1674 }
1675
1676 /* This function will re-initialize the se_rule field of all applicable rules.
1677 * It will traverse the filter lists serarching for rules that contain selinux
1678 * specific filter fields. When such a rule is found, it is copied, the
1679 * selinux field is re-initialized, and the old rule is replaced with the
1680 * updated rule. */
1681 int selinux_audit_rule_update(void)
1682 {
1683 struct audit_entry *entry, *n, *nentry;
1684 struct audit_watch *watch;
1685 int i, err = 0;
1686
1687 /* audit_filter_mutex synchronizes the writers */
1688 mutex_lock(&audit_filter_mutex);
1689
1690 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1691 list_for_each_entry_safe(entry, n, &audit_filter_list[i], list) {
1692 if (!audit_rule_has_selinux(&entry->rule))
1693 continue;
1694
1695 watch = entry->rule.watch;
1696 nentry = audit_dupe_rule(&entry->rule, watch);
1697 if (unlikely(IS_ERR(nentry))) {
1698 /* save the first error encountered for the
1699 * return value */
1700 if (!err)
1701 err = PTR_ERR(nentry);
1702 audit_panic("error updating selinux filters");
1703 if (watch)
1704 list_del(&entry->rule.rlist);
1705 list_del_rcu(&entry->list);
1706 } else {
1707 if (watch) {
1708 list_add(&nentry->rule.rlist,
1709 &watch->rules);
1710 list_del(&entry->rule.rlist);
1711 }
1712 list_replace_rcu(&entry->list, &nentry->list);
1713 }
1714 call_rcu(&entry->rcu, audit_free_rule_rcu);
1715 }
1716 }
1717
1718 mutex_unlock(&audit_filter_mutex);
1719
1720 return err;
1721 }
1722
1723 /* Update watch data in audit rules based on inotify events. */
1724 void audit_handle_ievent(struct inotify_watch *i_watch, u32 wd, u32 mask,
1725 u32 cookie, const char *dname, struct inode *inode)
1726 {
1727 struct audit_parent *parent;
1728
1729 parent = container_of(i_watch, struct audit_parent, wdata);
1730
1731 if (mask & (IN_CREATE|IN_MOVED_TO) && inode)
1732 audit_update_watch(parent, dname, inode->i_sb->s_dev,
1733 inode->i_ino, 0);
1734 else if (mask & (IN_DELETE|IN_MOVED_FROM))
1735 audit_update_watch(parent, dname, (dev_t)-1, (unsigned long)-1, 1);
1736 /* inotify automatically removes the watch and sends IN_IGNORED */
1737 else if (mask & (IN_DELETE_SELF|IN_UNMOUNT))
1738 audit_remove_parent_watches(parent);
1739 /* inotify does not remove the watch, so remove it manually */
1740 else if(mask & IN_MOVE_SELF) {
1741 audit_remove_parent_watches(parent);
1742 inotify_remove_watch_locked(audit_ih, i_watch);
1743 } else if (mask & IN_IGNORED)
1744 put_inotify_watch(i_watch);
1745 }
CRIS linux kernel tree