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Merge branch 'v2.6.25-rc3-lockdep' of git://git.kernel.org/pub/scm/linux/kernel/git...
[wrt350n-kernel.git] / kernel / auditfilter.c
blob2f2914b7cc302136c223b6bd44ff49ea6a30de24
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 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 extern int audit_enabled;
99
100 void audit_free_parent(struct inotify_watch *i_watch)
101 {
102 struct audit_parent *parent;
103
104 parent = container_of(i_watch, struct audit_parent, wdata);
105 WARN_ON(!list_empty(&parent->watches));
106 kfree(parent);
107 }
108
109 static inline void audit_get_watch(struct audit_watch *watch)
110 {
111 atomic_inc(&watch->count);
112 }
113
114 static void audit_put_watch(struct audit_watch *watch)
115 {
116 if (atomic_dec_and_test(&watch->count)) {
117 WARN_ON(watch->parent);
118 WARN_ON(!list_empty(&watch->rules));
119 kfree(watch->path);
120 kfree(watch);
121 }
122 }
123
124 static void audit_remove_watch(struct audit_watch *watch)
125 {
126 list_del(&watch->wlist);
127 put_inotify_watch(&watch->parent->wdata);
128 watch->parent = NULL;
129 audit_put_watch(watch); /* match initial get */
130 }
131
132 static inline void audit_free_rule(struct audit_entry *e)
133 {
134 int i;
135
136 /* some rules don't have associated watches */
137 if (e->rule.watch)
138 audit_put_watch(e->rule.watch);
139 if (e->rule.fields)
140 for (i = 0; i < e->rule.field_count; i++) {
141 struct audit_field *f = &e->rule.fields[i];
142 kfree(f->se_str);
143 selinux_audit_rule_free(f->se_rule);
144 }
145 kfree(e->rule.fields);
146 kfree(e->rule.filterkey);
147 kfree(e);
148 }
149
150 void audit_free_rule_rcu(struct rcu_head *head)
151 {
152 struct audit_entry *e = container_of(head, struct audit_entry, rcu);
153 audit_free_rule(e);
154 }
155
156 /* Initialize a parent watch entry. */
157 static struct audit_parent *audit_init_parent(struct nameidata *ndp)
158 {
159 struct audit_parent *parent;
160 s32 wd;
161
162 parent = kzalloc(sizeof(*parent), GFP_KERNEL);
163 if (unlikely(!parent))
164 return ERR_PTR(-ENOMEM);
165
166 INIT_LIST_HEAD(&parent->watches);
167 parent->flags = 0;
168
169 inotify_init_watch(&parent->wdata);
170 /* grab a ref so inotify watch hangs around until we take audit_filter_mutex */
171 get_inotify_watch(&parent->wdata);
172 wd = inotify_add_watch(audit_ih, &parent->wdata,
173 ndp->path.dentry->d_inode, AUDIT_IN_WATCH);
174 if (wd < 0) {
175 audit_free_parent(&parent->wdata);
176 return ERR_PTR(wd);
177 }
178
179 return parent;
180 }
181
182 /* Initialize a watch entry. */
183 static struct audit_watch *audit_init_watch(char *path)
184 {
185 struct audit_watch *watch;
186
187 watch = kzalloc(sizeof(*watch), GFP_KERNEL);
188 if (unlikely(!watch))
189 return ERR_PTR(-ENOMEM);
190
191 INIT_LIST_HEAD(&watch->rules);
192 atomic_set(&watch->count, 1);
193 watch->path = path;
194 watch->dev = (dev_t)-1;
195 watch->ino = (unsigned long)-1;
196
197 return watch;
198 }
199
200 /* Initialize an audit filterlist entry. */
201 static inline struct audit_entry *audit_init_entry(u32 field_count)
202 {
203 struct audit_entry *entry;
204 struct audit_field *fields;
205
206 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
207 if (unlikely(!entry))
208 return NULL;
209
210 fields = kzalloc(sizeof(*fields) * field_count, GFP_KERNEL);
211 if (unlikely(!fields)) {
212 kfree(entry);
213 return NULL;
214 }
215 entry->rule.fields = fields;
216
217 return entry;
218 }
219
220 /* Unpack a filter field's string representation from user-space
221 * buffer. */
222 char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
223 {
224 char *str;
225
226 if (!*bufp || (len == 0) || (len > *remain))
227 return ERR_PTR(-EINVAL);
228
229 /* Of the currently implemented string fields, PATH_MAX
230 * defines the longest valid length.
231 */
232 if (len > PATH_MAX)
233 return ERR_PTR(-ENAMETOOLONG);
234
235 str = kmalloc(len + 1, GFP_KERNEL);
236 if (unlikely(!str))
237 return ERR_PTR(-ENOMEM);
238
239 memcpy(str, *bufp, len);
240 str[len] = 0;
241 *bufp += len;
242 *remain -= len;
243
244 return str;
245 }
246
247 /* Translate an inode field to kernel respresentation. */
248 static inline int audit_to_inode(struct audit_krule *krule,
249 struct audit_field *f)
250 {
251 if (krule->listnr != AUDIT_FILTER_EXIT ||
252 krule->watch || krule->inode_f || krule->tree)
253 return -EINVAL;
254
255 krule->inode_f = f;
256 return 0;
257 }
258
259 /* Translate a watch string to kernel respresentation. */
260 static int audit_to_watch(struct audit_krule *krule, char *path, int len,
261 u32 op)
262 {
263 struct audit_watch *watch;
264
265 if (!audit_ih)
266 return -EOPNOTSUPP;
267
268 if (path[0] != '/' || path[len-1] == '/' ||
269 krule->listnr != AUDIT_FILTER_EXIT ||
270 op & ~AUDIT_EQUAL ||
271 krule->inode_f || krule->watch || krule->tree)
272 return -EINVAL;
273
274 watch = audit_init_watch(path);
275 if (unlikely(IS_ERR(watch)))
276 return PTR_ERR(watch);
277
278 audit_get_watch(watch);
279 krule->watch = watch;
280
281 return 0;
282 }
283
284 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
285
286 int __init audit_register_class(int class, unsigned *list)
287 {
288 __u32 *p = kzalloc(AUDIT_BITMASK_SIZE * sizeof(__u32), GFP_KERNEL);
289 if (!p)
290 return -ENOMEM;
291 while (*list != ~0U) {
292 unsigned n = *list++;
293 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
294 kfree(p);
295 return -EINVAL;
296 }
297 p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
298 }
299 if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
300 kfree(p);
301 return -EINVAL;
302 }
303 classes[class] = p;
304 return 0;
305 }
306
307 int audit_match_class(int class, unsigned syscall)
308 {
309 if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
310 return 0;
311 if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
312 return 0;
313 return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
314 }
315
316 #ifdef CONFIG_AUDITSYSCALL
317 static inline int audit_match_class_bits(int class, u32 *mask)
318 {
319 int i;
320
321 if (classes[class]) {
322 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
323 if (mask[i] & classes[class][i])
324 return 0;
325 }
326 return 1;
327 }
328
329 static int audit_match_signal(struct audit_entry *entry)
330 {
331 struct audit_field *arch = entry->rule.arch_f;
332
333 if (!arch) {
334 /* When arch is unspecified, we must check both masks on biarch
335 * as syscall number alone is ambiguous. */
336 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
337 entry->rule.mask) &&
338 audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
339 entry->rule.mask));
340 }
341
342 switch(audit_classify_arch(arch->val)) {
343 case 0: /* native */
344 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
345 entry->rule.mask));
346 case 1: /* 32bit on biarch */
347 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
348 entry->rule.mask));
349 default:
350 return 1;
351 }
352 }
353 #endif
354
355 /* Common user-space to kernel rule translation. */
356 static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule)
357 {
358 unsigned listnr;
359 struct audit_entry *entry;
360 int i, err;
361
362 err = -EINVAL;
363 listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
364 switch(listnr) {
365 default:
366 goto exit_err;
367 case AUDIT_FILTER_USER:
368 case AUDIT_FILTER_TYPE:
369 #ifdef CONFIG_AUDITSYSCALL
370 case AUDIT_FILTER_ENTRY:
371 case AUDIT_FILTER_EXIT:
372 case AUDIT_FILTER_TASK:
373 #endif
374 ;
375 }
376 if (unlikely(rule->action == AUDIT_POSSIBLE)) {
377 printk(KERN_ERR "AUDIT_POSSIBLE is deprecated\n");
378 goto exit_err;
379 }
380 if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
381 goto exit_err;
382 if (rule->field_count > AUDIT_MAX_FIELDS)
383 goto exit_err;
384
385 err = -ENOMEM;
386 entry = audit_init_entry(rule->field_count);
387 if (!entry)
388 goto exit_err;
389
390 entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
391 entry->rule.listnr = listnr;
392 entry->rule.action = rule->action;
393 entry->rule.field_count = rule->field_count;
394
395 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
396 entry->rule.mask[i] = rule->mask[i];
397
398 for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
399 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
400 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
401 __u32 *class;
402
403 if (!(*p & AUDIT_BIT(bit)))
404 continue;
405 *p &= ~AUDIT_BIT(bit);
406 class = classes[i];
407 if (class) {
408 int j;
409 for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
410 entry->rule.mask[j] |= class[j];
411 }
412 }
413
414 return entry;
415
416 exit_err:
417 return ERR_PTR(err);
418 }
419
420 /* Translate struct audit_rule to kernel's rule respresentation.
421 * Exists for backward compatibility with userspace. */
422 static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
423 {
424 struct audit_entry *entry;
425 struct audit_field *f;
426 int err = 0;
427 int i;
428
429 entry = audit_to_entry_common(rule);
430 if (IS_ERR(entry))
431 goto exit_nofree;
432
433 for (i = 0; i < rule->field_count; i++) {
434 struct audit_field *f = &entry->rule.fields[i];
435
436 f->op = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS);
437 f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS);
438 f->val = rule->values[i];
439
440 err = -EINVAL;
441 switch(f->type) {
442 default:
443 goto exit_free;
444 case AUDIT_PID:
445 case AUDIT_UID:
446 case AUDIT_EUID:
447 case AUDIT_SUID:
448 case AUDIT_FSUID:
449 case AUDIT_GID:
450 case AUDIT_EGID:
451 case AUDIT_SGID:
452 case AUDIT_FSGID:
453 case AUDIT_LOGINUID:
454 case AUDIT_PERS:
455 case AUDIT_MSGTYPE:
456 case AUDIT_PPID:
457 case AUDIT_DEVMAJOR:
458 case AUDIT_DEVMINOR:
459 case AUDIT_EXIT:
460 case AUDIT_SUCCESS:
461 /* bit ops are only useful on syscall args */
462 if (f->op == AUDIT_BIT_MASK ||
463 f->op == AUDIT_BIT_TEST) {
464 err = -EINVAL;
465 goto exit_free;
466 }
467 break;
468 case AUDIT_ARG0:
469 case AUDIT_ARG1:
470 case AUDIT_ARG2:
471 case AUDIT_ARG3:
472 break;
473 /* arch is only allowed to be = or != */
474 case AUDIT_ARCH:
475 if ((f->op != AUDIT_NOT_EQUAL) && (f->op != AUDIT_EQUAL)
476 && (f->op != AUDIT_NEGATE) && (f->op)) {
477 err = -EINVAL;
478 goto exit_free;
479 }
480 entry->rule.arch_f = f;
481 break;
482 case AUDIT_PERM:
483 if (f->val & ~15)
484 goto exit_free;
485 break;
486 case AUDIT_INODE:
487 err = audit_to_inode(&entry->rule, f);
488 if (err)
489 goto exit_free;
490 break;
491 }
492
493 entry->rule.vers_ops = (f->op & AUDIT_OPERATORS) ? 2 : 1;
494
495 /* Support for legacy operators where
496 * AUDIT_NEGATE bit signifies != and otherwise assumes == */
497 if (f->op & AUDIT_NEGATE)
498 f->op = AUDIT_NOT_EQUAL;
499 else if (!f->op)
500 f->op = AUDIT_EQUAL;
501 else if (f->op == AUDIT_OPERATORS) {
502 err = -EINVAL;
503 goto exit_free;
504 }
505 }
506
507 f = entry->rule.inode_f;
508 if (f) {
509 switch(f->op) {
510 case AUDIT_NOT_EQUAL:
511 entry->rule.inode_f = NULL;
512 case AUDIT_EQUAL:
513 break;
514 default:
515 err = -EINVAL;
516 goto exit_free;
517 }
518 }
519
520 exit_nofree:
521 return entry;
522
523 exit_free:
524 audit_free_rule(entry);
525 return ERR_PTR(err);
526 }
527
528 /* Translate struct audit_rule_data to kernel's rule respresentation. */
529 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
530 size_t datasz)
531 {
532 int err = 0;
533 struct audit_entry *entry;
534 struct audit_field *f;
535 void *bufp;
536 size_t remain = datasz - sizeof(struct audit_rule_data);
537 int i;
538 char *str;
539
540 entry = audit_to_entry_common((struct audit_rule *)data);
541 if (IS_ERR(entry))
542 goto exit_nofree;
543
544 bufp = data->buf;
545 entry->rule.vers_ops = 2;
546 for (i = 0; i < data->field_count; i++) {
547 struct audit_field *f = &entry->rule.fields[i];
548
549 err = -EINVAL;
550 if (!(data->fieldflags[i] & AUDIT_OPERATORS) ||
551 data->fieldflags[i] & ~AUDIT_OPERATORS)
552 goto exit_free;
553
554 f->op = data->fieldflags[i] & AUDIT_OPERATORS;
555 f->type = data->fields[i];
556 f->val = data->values[i];
557 f->se_str = NULL;
558 f->se_rule = NULL;
559 switch(f->type) {
560 case AUDIT_PID:
561 case AUDIT_UID:
562 case AUDIT_EUID:
563 case AUDIT_SUID:
564 case AUDIT_FSUID:
565 case AUDIT_GID:
566 case AUDIT_EGID:
567 case AUDIT_SGID:
568 case AUDIT_FSGID:
569 case AUDIT_LOGINUID:
570 case AUDIT_PERS:
571 case AUDIT_MSGTYPE:
572 case AUDIT_PPID:
573 case AUDIT_DEVMAJOR:
574 case AUDIT_DEVMINOR:
575 case AUDIT_EXIT:
576 case AUDIT_SUCCESS:
577 case AUDIT_ARG0:
578 case AUDIT_ARG1:
579 case AUDIT_ARG2:
580 case AUDIT_ARG3:
581 break;
582 case AUDIT_ARCH:
583 entry->rule.arch_f = f;
584 break;
585 case AUDIT_SUBJ_USER:
586 case AUDIT_SUBJ_ROLE:
587 case AUDIT_SUBJ_TYPE:
588 case AUDIT_SUBJ_SEN:
589 case AUDIT_SUBJ_CLR:
590 case AUDIT_OBJ_USER:
591 case AUDIT_OBJ_ROLE:
592 case AUDIT_OBJ_TYPE:
593 case AUDIT_OBJ_LEV_LOW:
594 case AUDIT_OBJ_LEV_HIGH:
595 str = audit_unpack_string(&bufp, &remain, f->val);
596 if (IS_ERR(str))
597 goto exit_free;
598 entry->rule.buflen += f->val;
599
600 err = selinux_audit_rule_init(f->type, f->op, str,
601 &f->se_rule);
602 /* Keep currently invalid fields around in case they
603 * become valid after a policy reload. */
604 if (err == -EINVAL) {
605 printk(KERN_WARNING "audit rule for selinux "
606 "\'%s\' is invalid\n", str);
607 err = 0;
608 }
609 if (err) {
610 kfree(str);
611 goto exit_free;
612 } else
613 f->se_str = str;
614 break;
615 case AUDIT_WATCH:
616 str = audit_unpack_string(&bufp, &remain, f->val);
617 if (IS_ERR(str))
618 goto exit_free;
619 entry->rule.buflen += f->val;
620
621 err = audit_to_watch(&entry->rule, str, f->val, f->op);
622 if (err) {
623 kfree(str);
624 goto exit_free;
625 }
626 break;
627 case AUDIT_DIR:
628 str = audit_unpack_string(&bufp, &remain, f->val);
629 if (IS_ERR(str))
630 goto exit_free;
631 entry->rule.buflen += f->val;
632
633 err = audit_make_tree(&entry->rule, str, f->op);
634 kfree(str);
635 if (err)
636 goto exit_free;
637 break;
638 case AUDIT_INODE:
639 err = audit_to_inode(&entry->rule, f);
640 if (err)
641 goto exit_free;
642 break;
643 case AUDIT_FILTERKEY:
644 err = -EINVAL;
645 if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
646 goto exit_free;
647 str = audit_unpack_string(&bufp, &remain, f->val);
648 if (IS_ERR(str))
649 goto exit_free;
650 entry->rule.buflen += f->val;
651 entry->rule.filterkey = str;
652 break;
653 case AUDIT_PERM:
654 if (f->val & ~15)
655 goto exit_free;
656 break;
657 default:
658 goto exit_free;
659 }
660 }
661
662 f = entry->rule.inode_f;
663 if (f) {
664 switch(f->op) {
665 case AUDIT_NOT_EQUAL:
666 entry->rule.inode_f = NULL;
667 case AUDIT_EQUAL:
668 break;
669 default:
670 err = -EINVAL;
671 goto exit_free;
672 }
673 }
674
675 exit_nofree:
676 return entry;
677
678 exit_free:
679 audit_free_rule(entry);
680 return ERR_PTR(err);
681 }
682
683 /* Pack a filter field's string representation into data block. */
684 static inline size_t audit_pack_string(void **bufp, const char *str)
685 {
686 size_t len = strlen(str);
687
688 memcpy(*bufp, str, len);
689 *bufp += len;
690
691 return len;
692 }
693
694 /* Translate kernel rule respresentation to struct audit_rule.
695 * Exists for backward compatibility with userspace. */
696 static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
697 {
698 struct audit_rule *rule;
699 int i;
700
701 rule = kzalloc(sizeof(*rule), GFP_KERNEL);
702 if (unlikely(!rule))
703 return NULL;
704
705 rule->flags = krule->flags | krule->listnr;
706 rule->action = krule->action;
707 rule->field_count = krule->field_count;
708 for (i = 0; i < rule->field_count; i++) {
709 rule->values[i] = krule->fields[i].val;
710 rule->fields[i] = krule->fields[i].type;
711
712 if (krule->vers_ops == 1) {
713 if (krule->fields[i].op & AUDIT_NOT_EQUAL)
714 rule->fields[i] |= AUDIT_NEGATE;
715 } else {
716 rule->fields[i] |= krule->fields[i].op;
717 }
718 }
719 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
720
721 return rule;
722 }
723
724 /* Translate kernel rule respresentation to struct audit_rule_data. */
725 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
726 {
727 struct audit_rule_data *data;
728 void *bufp;
729 int i;
730
731 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
732 if (unlikely(!data))
733 return NULL;
734 memset(data, 0, sizeof(*data));
735
736 data->flags = krule->flags | krule->listnr;
737 data->action = krule->action;
738 data->field_count = krule->field_count;
739 bufp = data->buf;
740 for (i = 0; i < data->field_count; i++) {
741 struct audit_field *f = &krule->fields[i];
742
743 data->fields[i] = f->type;
744 data->fieldflags[i] = f->op;
745 switch(f->type) {
746 case AUDIT_SUBJ_USER:
747 case AUDIT_SUBJ_ROLE:
748 case AUDIT_SUBJ_TYPE:
749 case AUDIT_SUBJ_SEN:
750 case AUDIT_SUBJ_CLR:
751 case AUDIT_OBJ_USER:
752 case AUDIT_OBJ_ROLE:
753 case AUDIT_OBJ_TYPE:
754 case AUDIT_OBJ_LEV_LOW:
755 case AUDIT_OBJ_LEV_HIGH:
756 data->buflen += data->values[i] =
757 audit_pack_string(&bufp, f->se_str);
758 break;
759 case AUDIT_WATCH:
760 data->buflen += data->values[i] =
761 audit_pack_string(&bufp, krule->watch->path);
762 break;
763 case AUDIT_DIR:
764 data->buflen += data->values[i] =
765 audit_pack_string(&bufp,
766 audit_tree_path(krule->tree));
767 break;
768 case AUDIT_FILTERKEY:
769 data->buflen += data->values[i] =
770 audit_pack_string(&bufp, krule->filterkey);
771 break;
772 default:
773 data->values[i] = f->val;
774 }
775 }
776 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
777
778 return data;
779 }
780
781 /* Compare two rules in kernel format. Considered success if rules
782 * don't match. */
783 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
784 {
785 int i;
786
787 if (a->flags != b->flags ||
788 a->listnr != b->listnr ||
789 a->action != b->action ||
790 a->field_count != b->field_count)
791 return 1;
792
793 for (i = 0; i < a->field_count; i++) {
794 if (a->fields[i].type != b->fields[i].type ||
795 a->fields[i].op != b->fields[i].op)
796 return 1;
797
798 switch(a->fields[i].type) {
799 case AUDIT_SUBJ_USER:
800 case AUDIT_SUBJ_ROLE:
801 case AUDIT_SUBJ_TYPE:
802 case AUDIT_SUBJ_SEN:
803 case AUDIT_SUBJ_CLR:
804 case AUDIT_OBJ_USER:
805 case AUDIT_OBJ_ROLE:
806 case AUDIT_OBJ_TYPE:
807 case AUDIT_OBJ_LEV_LOW:
808 case AUDIT_OBJ_LEV_HIGH:
809 if (strcmp(a->fields[i].se_str, b->fields[i].se_str))
810 return 1;
811 break;
812 case AUDIT_WATCH:
813 if (strcmp(a->watch->path, b->watch->path))
814 return 1;
815 break;
816 case AUDIT_DIR:
817 if (strcmp(audit_tree_path(a->tree),
818 audit_tree_path(b->tree)))
819 return 1;
820 break;
821 case AUDIT_FILTERKEY:
822 /* both filterkeys exist based on above type compare */
823 if (strcmp(a->filterkey, b->filterkey))
824 return 1;
825 break;
826 default:
827 if (a->fields[i].val != b->fields[i].val)
828 return 1;
829 }
830 }
831
832 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
833 if (a->mask[i] != b->mask[i])
834 return 1;
835
836 return 0;
837 }
838
839 /* Duplicate the given audit watch. The new watch's rules list is initialized
840 * to an empty list and wlist is undefined. */
841 static struct audit_watch *audit_dupe_watch(struct audit_watch *old)
842 {
843 char *path;
844 struct audit_watch *new;
845
846 path = kstrdup(old->path, GFP_KERNEL);
847 if (unlikely(!path))
848 return ERR_PTR(-ENOMEM);
849
850 new = audit_init_watch(path);
851 if (unlikely(IS_ERR(new))) {
852 kfree(path);
853 goto out;
854 }
855
856 new->dev = old->dev;
857 new->ino = old->ino;
858 get_inotify_watch(&old->parent->wdata);
859 new->parent = old->parent;
860
861 out:
862 return new;
863 }
864
865 /* Duplicate selinux field information. The se_rule is opaque, so must be
866 * re-initialized. */
867 static inline int audit_dupe_selinux_field(struct audit_field *df,
868 struct audit_field *sf)
869 {
870 int ret = 0;
871 char *se_str;
872
873 /* our own copy of se_str */
874 se_str = kstrdup(sf->se_str, GFP_KERNEL);
875 if (unlikely(!se_str))
876 return -ENOMEM;
877 df->se_str = se_str;
878
879 /* our own (refreshed) copy of se_rule */
880 ret = selinux_audit_rule_init(df->type, df->op, df->se_str,
881 &df->se_rule);
882 /* Keep currently invalid fields around in case they
883 * become valid after a policy reload. */
884 if (ret == -EINVAL) {
885 printk(KERN_WARNING "audit rule for selinux \'%s\' is "
886 "invalid\n", df->se_str);
887 ret = 0;
888 }
889
890 return ret;
891 }
892
893 /* Duplicate an audit rule. This will be a deep copy with the exception
894 * of the watch - that pointer is carried over. The selinux specific fields
895 * will be updated in the copy. The point is to be able to replace the old
896 * rule with the new rule in the filterlist, then free the old rule.
897 * The rlist element is undefined; list manipulations are handled apart from
898 * the initial copy. */
899 static struct audit_entry *audit_dupe_rule(struct audit_krule *old,
900 struct audit_watch *watch)
901 {
902 u32 fcount = old->field_count;
903 struct audit_entry *entry;
904 struct audit_krule *new;
905 char *fk;
906 int i, err = 0;
907
908 entry = audit_init_entry(fcount);
909 if (unlikely(!entry))
910 return ERR_PTR(-ENOMEM);
911
912 new = &entry->rule;
913 new->vers_ops = old->vers_ops;
914 new->flags = old->flags;
915 new->listnr = old->listnr;
916 new->action = old->action;
917 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
918 new->mask[i] = old->mask[i];
919 new->buflen = old->buflen;
920 new->inode_f = old->inode_f;
921 new->watch = NULL;
922 new->field_count = old->field_count;
923 /*
924 * note that we are OK with not refcounting here; audit_match_tree()
925 * never dereferences tree and we can't get false positives there
926 * since we'd have to have rule gone from the list *and* removed
927 * before the chunks found by lookup had been allocated, i.e. before
928 * the beginning of list scan.
929 */
930 new->tree = old->tree;
931 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
932
933 /* deep copy this information, updating the se_rule fields, because
934 * the originals will all be freed when the old rule is freed. */
935 for (i = 0; i < fcount; i++) {
936 switch (new->fields[i].type) {
937 case AUDIT_SUBJ_USER:
938 case AUDIT_SUBJ_ROLE:
939 case AUDIT_SUBJ_TYPE:
940 case AUDIT_SUBJ_SEN:
941 case AUDIT_SUBJ_CLR:
942 case AUDIT_OBJ_USER:
943 case AUDIT_OBJ_ROLE:
944 case AUDIT_OBJ_TYPE:
945 case AUDIT_OBJ_LEV_LOW:
946 case AUDIT_OBJ_LEV_HIGH:
947 err = audit_dupe_selinux_field(&new->fields[i],
948 &old->fields[i]);
949 break;
950 case AUDIT_FILTERKEY:
951 fk = kstrdup(old->filterkey, GFP_KERNEL);
952 if (unlikely(!fk))
953 err = -ENOMEM;
954 else
955 new->filterkey = fk;
956 }
957 if (err) {
958 audit_free_rule(entry);
959 return ERR_PTR(err);
960 }
961 }
962
963 if (watch) {
964 audit_get_watch(watch);
965 new->watch = watch;
966 }
967
968 return entry;
969 }
970
971 /* Update inode info in audit rules based on filesystem event. */
972 static void audit_update_watch(struct audit_parent *parent,
973 const char *dname, dev_t dev,
974 unsigned long ino, unsigned invalidating)
975 {
976 struct audit_watch *owatch, *nwatch, *nextw;
977 struct audit_krule *r, *nextr;
978 struct audit_entry *oentry, *nentry;
979
980 mutex_lock(&audit_filter_mutex);
981 list_for_each_entry_safe(owatch, nextw, &parent->watches, wlist) {
982 if (audit_compare_dname_path(dname, owatch->path, NULL))
983 continue;
984
985 /* If the update involves invalidating rules, do the inode-based
986 * filtering now, so we don't omit records. */
987 if (invalidating && current->audit_context &&
988 audit_filter_inodes(current, current->audit_context) == AUDIT_RECORD_CONTEXT)
989 audit_set_auditable(current->audit_context);
990
991 nwatch = audit_dupe_watch(owatch);
992 if (unlikely(IS_ERR(nwatch))) {
993 mutex_unlock(&audit_filter_mutex);
994 audit_panic("error updating watch, skipping");
995 return;
996 }
997 nwatch->dev = dev;
998 nwatch->ino = ino;
999
1000 list_for_each_entry_safe(r, nextr, &owatch->rules, rlist) {
1001
1002 oentry = container_of(r, struct audit_entry, rule);
1003 list_del(&oentry->rule.rlist);
1004 list_del_rcu(&oentry->list);
1005
1006 nentry = audit_dupe_rule(&oentry->rule, nwatch);
1007 if (unlikely(IS_ERR(nentry)))
1008 audit_panic("error updating watch, removing");
1009 else {
1010 int h = audit_hash_ino((u32)ino);
1011 list_add(&nentry->rule.rlist, &nwatch->rules);
1012 list_add_rcu(&nentry->list, &audit_inode_hash[h]);
1013 }
1014
1015 call_rcu(&oentry->rcu, audit_free_rule_rcu);
1016 }
1017
1018 if (audit_enabled) {
1019 struct audit_buffer *ab;
1020 ab = audit_log_start(NULL, GFP_KERNEL,
1021 AUDIT_CONFIG_CHANGE);
1022 audit_log_format(ab,
1023 "op=updated rules specifying path=");
1024 audit_log_untrustedstring(ab, owatch->path);
1025 audit_log_format(ab, " with dev=%u ino=%lu\n",
1026 dev, ino);
1027 audit_log_format(ab, " list=%d res=1", r->listnr);
1028 audit_log_end(ab);
1029 }
1030 audit_remove_watch(owatch);
1031 goto add_watch_to_parent; /* event applies to a single watch */
1032 }
1033 mutex_unlock(&audit_filter_mutex);
1034 return;
1035
1036 add_watch_to_parent:
1037 list_add(&nwatch->wlist, &parent->watches);
1038 mutex_unlock(&audit_filter_mutex);
1039 return;
1040 }
1041
1042 /* Remove all watches & rules associated with a parent that is going away. */
1043 static void audit_remove_parent_watches(struct audit_parent *parent)
1044 {
1045 struct audit_watch *w, *nextw;
1046 struct audit_krule *r, *nextr;
1047 struct audit_entry *e;
1048
1049 mutex_lock(&audit_filter_mutex);
1050 parent->flags |= AUDIT_PARENT_INVALID;
1051 list_for_each_entry_safe(w, nextw, &parent->watches, wlist) {
1052 list_for_each_entry_safe(r, nextr, &w->rules, rlist) {
1053 e = container_of(r, struct audit_entry, rule);
1054 if (audit_enabled) {
1055 struct audit_buffer *ab;
1056 ab = audit_log_start(NULL, GFP_KERNEL,
1057 AUDIT_CONFIG_CHANGE);
1058 audit_log_format(ab, "op=remove rule path=");
1059 audit_log_untrustedstring(ab, w->path);
1060 if (r->filterkey) {
1061 audit_log_format(ab, " key=");
1062 audit_log_untrustedstring(ab,
1063 r->filterkey);
1064 } else
1065 audit_log_format(ab, " key=(null)");
1066 audit_log_format(ab, " list=%d res=1",
1067 r->listnr);
1068 audit_log_end(ab);
1069 }
1070 list_del(&r->rlist);
1071 list_del_rcu(&e->list);
1072 call_rcu(&e->rcu, audit_free_rule_rcu);
1073 }
1074 audit_remove_watch(w);
1075 }
1076 mutex_unlock(&audit_filter_mutex);
1077 }
1078
1079 /* Unregister inotify watches for parents on in_list.
1080 * Generates an IN_IGNORED event. */
1081 static void audit_inotify_unregister(struct list_head *in_list)
1082 {
1083 struct audit_parent *p, *n;
1084
1085 list_for_each_entry_safe(p, n, in_list, ilist) {
1086 list_del(&p->ilist);
1087 inotify_rm_watch(audit_ih, &p->wdata);
1088 /* the put matching the get in audit_do_del_rule() */
1089 put_inotify_watch(&p->wdata);
1090 }
1091 }
1092
1093 /* Find an existing audit rule.
1094 * Caller must hold audit_filter_mutex to prevent stale rule data. */
1095 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
1096 struct list_head *list)
1097 {
1098 struct audit_entry *e, *found = NULL;
1099 int h;
1100
1101 if (entry->rule.watch) {
1102 /* we don't know the inode number, so must walk entire hash */
1103 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
1104 list = &audit_inode_hash[h];
1105 list_for_each_entry(e, list, list)
1106 if (!audit_compare_rule(&entry->rule, &e->rule)) {
1107 found = e;
1108 goto out;
1109 }
1110 }
1111 goto out;
1112 }
1113
1114 list_for_each_entry(e, list, list)
1115 if (!audit_compare_rule(&entry->rule, &e->rule)) {
1116 found = e;
1117 goto out;
1118 }
1119
1120 out:
1121 return found;
1122 }
1123
1124 /* Get path information necessary for adding watches. */
1125 static int audit_get_nd(char *path, struct nameidata **ndp,
1126 struct nameidata **ndw)
1127 {
1128 struct nameidata *ndparent, *ndwatch;
1129 int err;
1130
1131 ndparent = kmalloc(sizeof(*ndparent), GFP_KERNEL);
1132 if (unlikely(!ndparent))
1133 return -ENOMEM;
1134
1135 ndwatch = kmalloc(sizeof(*ndwatch), GFP_KERNEL);
1136 if (unlikely(!ndwatch)) {
1137 kfree(ndparent);
1138 return -ENOMEM;
1139 }
1140
1141 err = path_lookup(path, LOOKUP_PARENT, ndparent);
1142 if (err) {
1143 kfree(ndparent);
1144 kfree(ndwatch);
1145 return err;
1146 }
1147
1148 err = path_lookup(path, 0, ndwatch);
1149 if (err) {
1150 kfree(ndwatch);
1151 ndwatch = NULL;
1152 }
1153
1154 *ndp = ndparent;
1155 *ndw = ndwatch;
1156
1157 return 0;
1158 }
1159
1160 /* Release resources used for watch path information. */
1161 static void audit_put_nd(struct nameidata *ndp, struct nameidata *ndw)
1162 {
1163 if (ndp) {
1164 path_put(&ndp->path);
1165 kfree(ndp);
1166 }
1167 if (ndw) {
1168 path_put(&ndw->path);
1169 kfree(ndw);
1170 }
1171 }
1172
1173 /* Associate the given rule with an existing parent inotify_watch.
1174 * Caller must hold audit_filter_mutex. */
1175 static void audit_add_to_parent(struct audit_krule *krule,
1176 struct audit_parent *parent)
1177 {
1178 struct audit_watch *w, *watch = krule->watch;
1179 int watch_found = 0;
1180
1181 list_for_each_entry(w, &parent->watches, wlist) {
1182 if (strcmp(watch->path, w->path))
1183 continue;
1184
1185 watch_found = 1;
1186
1187 /* put krule's and initial refs to temporary watch */
1188 audit_put_watch(watch);
1189 audit_put_watch(watch);
1190
1191 audit_get_watch(w);
1192 krule->watch = watch = w;
1193 break;
1194 }
1195
1196 if (!watch_found) {
1197 get_inotify_watch(&parent->wdata);
1198 watch->parent = parent;
1199
1200 list_add(&watch->wlist, &parent->watches);
1201 }
1202 list_add(&krule->rlist, &watch->rules);
1203 }
1204
1205 /* Find a matching watch entry, or add this one.
1206 * Caller must hold audit_filter_mutex. */
1207 static int audit_add_watch(struct audit_krule *krule, struct nameidata *ndp,
1208 struct nameidata *ndw)
1209 {
1210 struct audit_watch *watch = krule->watch;
1211 struct inotify_watch *i_watch;
1212 struct audit_parent *parent;
1213 int ret = 0;
1214
1215 /* update watch filter fields */
1216 if (ndw) {
1217 watch->dev = ndw->path.dentry->d_inode->i_sb->s_dev;
1218 watch->ino = ndw->path.dentry->d_inode->i_ino;
1219 }
1220
1221 /* The audit_filter_mutex must not be held during inotify calls because
1222 * we hold it during inotify event callback processing. If an existing
1223 * inotify watch is found, inotify_find_watch() grabs a reference before
1224 * returning.
1225 */
1226 mutex_unlock(&audit_filter_mutex);
1227
1228 if (inotify_find_watch(audit_ih, ndp->path.dentry->d_inode,
1229 &i_watch) < 0) {
1230 parent = audit_init_parent(ndp);
1231 if (IS_ERR(parent)) {
1232 /* caller expects mutex locked */
1233 mutex_lock(&audit_filter_mutex);
1234 return PTR_ERR(parent);
1235 }
1236 } else
1237 parent = container_of(i_watch, struct audit_parent, wdata);
1238
1239 mutex_lock(&audit_filter_mutex);
1240
1241 /* parent was moved before we took audit_filter_mutex */
1242 if (parent->flags & AUDIT_PARENT_INVALID)
1243 ret = -ENOENT;
1244 else
1245 audit_add_to_parent(krule, parent);
1246
1247 /* match get in audit_init_parent or inotify_find_watch */
1248 put_inotify_watch(&parent->wdata);
1249 return ret;
1250 }
1251
1252 /* Add rule to given filterlist if not a duplicate. */
1253 static inline int audit_add_rule(struct audit_entry *entry,
1254 struct list_head *list)
1255 {
1256 struct audit_entry *e;
1257 struct audit_field *inode_f = entry->rule.inode_f;
1258 struct audit_watch *watch = entry->rule.watch;
1259 struct audit_tree *tree = entry->rule.tree;
1260 struct nameidata *ndp = NULL, *ndw = NULL;
1261 int h, err;
1262 #ifdef CONFIG_AUDITSYSCALL
1263 int dont_count = 0;
1264
1265 /* If either of these, don't count towards total */
1266 if (entry->rule.listnr == AUDIT_FILTER_USER ||
1267 entry->rule.listnr == AUDIT_FILTER_TYPE)
1268 dont_count = 1;
1269 #endif
1270
1271 if (inode_f) {
1272 h = audit_hash_ino(inode_f->val);
1273 list = &audit_inode_hash[h];
1274 }
1275
1276 mutex_lock(&audit_filter_mutex);
1277 e = audit_find_rule(entry, list);
1278 mutex_unlock(&audit_filter_mutex);
1279 if (e) {
1280 err = -EEXIST;
1281 /* normally audit_add_tree_rule() will free it on failure */
1282 if (tree)
1283 audit_put_tree(tree);
1284 goto error;
1285 }
1286
1287 /* Avoid calling path_lookup under audit_filter_mutex. */
1288 if (watch) {
1289 err = audit_get_nd(watch->path, &ndp, &ndw);
1290 if (err)
1291 goto error;
1292 }
1293
1294 mutex_lock(&audit_filter_mutex);
1295 if (watch) {
1296 /* audit_filter_mutex is dropped and re-taken during this call */
1297 err = audit_add_watch(&entry->rule, ndp, ndw);
1298 if (err) {
1299 mutex_unlock(&audit_filter_mutex);
1300 goto error;
1301 }
1302 h = audit_hash_ino((u32)watch->ino);
1303 list = &audit_inode_hash[h];
1304 }
1305 if (tree) {
1306 err = audit_add_tree_rule(&entry->rule);
1307 if (err) {
1308 mutex_unlock(&audit_filter_mutex);
1309 goto error;
1310 }
1311 }
1312
1313 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
1314 list_add_rcu(&entry->list, list);
1315 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
1316 } else {
1317 list_add_tail_rcu(&entry->list, list);
1318 }
1319 #ifdef CONFIG_AUDITSYSCALL
1320 if (!dont_count)
1321 audit_n_rules++;
1322
1323 if (!audit_match_signal(entry))
1324 audit_signals++;
1325 #endif
1326 mutex_unlock(&audit_filter_mutex);
1327
1328 audit_put_nd(ndp, ndw); /* NULL args OK */
1329 return 0;
1330
1331 error:
1332 audit_put_nd(ndp, ndw); /* NULL args OK */
1333 if (watch)
1334 audit_put_watch(watch); /* tmp watch, matches initial get */
1335 return err;
1336 }
1337
1338 /* Remove an existing rule from filterlist. */
1339 static inline int audit_del_rule(struct audit_entry *entry,
1340 struct list_head *list)
1341 {
1342 struct audit_entry *e;
1343 struct audit_field *inode_f = entry->rule.inode_f;
1344 struct audit_watch *watch, *tmp_watch = entry->rule.watch;
1345 struct audit_tree *tree = entry->rule.tree;
1346 LIST_HEAD(inotify_list);
1347 int h, ret = 0;
1348 #ifdef CONFIG_AUDITSYSCALL
1349 int dont_count = 0;
1350
1351 /* If either of these, don't count towards total */
1352 if (entry->rule.listnr == AUDIT_FILTER_USER ||
1353 entry->rule.listnr == AUDIT_FILTER_TYPE)
1354 dont_count = 1;
1355 #endif
1356
1357 if (inode_f) {
1358 h = audit_hash_ino(inode_f->val);
1359 list = &audit_inode_hash[h];
1360 }
1361
1362 mutex_lock(&audit_filter_mutex);
1363 e = audit_find_rule(entry, list);
1364 if (!e) {
1365 mutex_unlock(&audit_filter_mutex);
1366 ret = -ENOENT;
1367 goto out;
1368 }
1369
1370 watch = e->rule.watch;
1371 if (watch) {
1372 struct audit_parent *parent = watch->parent;
1373
1374 list_del(&e->rule.rlist);
1375
1376 if (list_empty(&watch->rules)) {
1377 audit_remove_watch(watch);
1378
1379 if (list_empty(&parent->watches)) {
1380 /* Put parent on the inotify un-registration
1381 * list. Grab a reference before releasing
1382 * audit_filter_mutex, to be released in
1383 * audit_inotify_unregister(). */
1384 list_add(&parent->ilist, &inotify_list);
1385 get_inotify_watch(&parent->wdata);
1386 }
1387 }
1388 }
1389
1390 if (e->rule.tree)
1391 audit_remove_tree_rule(&e->rule);
1392
1393 list_del_rcu(&e->list);
1394 call_rcu(&e->rcu, audit_free_rule_rcu);
1395
1396 #ifdef CONFIG_AUDITSYSCALL
1397 if (!dont_count)
1398 audit_n_rules--;
1399
1400 if (!audit_match_signal(entry))
1401 audit_signals--;
1402 #endif
1403 mutex_unlock(&audit_filter_mutex);
1404
1405 if (!list_empty(&inotify_list))
1406 audit_inotify_unregister(&inotify_list);
1407
1408 out:
1409 if (tmp_watch)
1410 audit_put_watch(tmp_watch); /* match initial get */
1411 if (tree)
1412 audit_put_tree(tree); /* that's the temporary one */
1413
1414 return ret;
1415 }
1416
1417 /* List rules using struct audit_rule. Exists for backward
1418 * compatibility with userspace. */
1419 static void audit_list(int pid, int seq, struct sk_buff_head *q)
1420 {
1421 struct sk_buff *skb;
1422 struct audit_entry *entry;
1423 int i;
1424
1425 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1426 * iterator to sync with list writers. */
1427 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1428 list_for_each_entry(entry, &audit_filter_list[i], list) {
1429 struct audit_rule *rule;
1430
1431 rule = audit_krule_to_rule(&entry->rule);
1432 if (unlikely(!rule))
1433 break;
1434 skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1435 rule, sizeof(*rule));
1436 if (skb)
1437 skb_queue_tail(q, skb);
1438 kfree(rule);
1439 }
1440 }
1441 for (i = 0; i < AUDIT_INODE_BUCKETS; i++) {
1442 list_for_each_entry(entry, &audit_inode_hash[i], list) {
1443 struct audit_rule *rule;
1444
1445 rule = audit_krule_to_rule(&entry->rule);
1446 if (unlikely(!rule))
1447 break;
1448 skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1449 rule, sizeof(*rule));
1450 if (skb)
1451 skb_queue_tail(q, skb);
1452 kfree(rule);
1453 }
1454 }
1455 skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
1456 if (skb)
1457 skb_queue_tail(q, skb);
1458 }
1459
1460 /* List rules using struct audit_rule_data. */
1461 static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
1462 {
1463 struct sk_buff *skb;
1464 struct audit_entry *e;
1465 int i;
1466
1467 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1468 * iterator to sync with list writers. */
1469 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1470 list_for_each_entry(e, &audit_filter_list[i], list) {
1471 struct audit_rule_data *data;
1472
1473 data = audit_krule_to_data(&e->rule);
1474 if (unlikely(!data))
1475 break;
1476 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1477 data, sizeof(*data) + data->buflen);
1478 if (skb)
1479 skb_queue_tail(q, skb);
1480 kfree(data);
1481 }
1482 }
1483 for (i=0; i< AUDIT_INODE_BUCKETS; i++) {
1484 list_for_each_entry(e, &audit_inode_hash[i], list) {
1485 struct audit_rule_data *data;
1486
1487 data = audit_krule_to_data(&e->rule);
1488 if (unlikely(!data))
1489 break;
1490 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1491 data, sizeof(*data) + data->buflen);
1492 if (skb)
1493 skb_queue_tail(q, skb);
1494 kfree(data);
1495 }
1496 }
1497 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1498 if (skb)
1499 skb_queue_tail(q, skb);
1500 }
1501
1502 /* Log rule additions and removals */
1503 static void audit_log_rule_change(uid_t loginuid, u32 sid, char *action,
1504 struct audit_krule *rule, int res)
1505 {
1506 struct audit_buffer *ab;
1507
1508 if (!audit_enabled)
1509 return;
1510
1511 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1512 if (!ab)
1513 return;
1514 audit_log_format(ab, "auid=%u", loginuid);
1515 if (sid) {
1516 char *ctx = NULL;
1517 u32 len;
1518 if (selinux_sid_to_string(sid, &ctx, &len))
1519 audit_log_format(ab, " ssid=%u", sid);
1520 else
1521 audit_log_format(ab, " subj=%s", ctx);
1522 kfree(ctx);
1523 }
1524 audit_log_format(ab, " op=%s rule key=", action);
1525 if (rule->filterkey)
1526 audit_log_untrustedstring(ab, rule->filterkey);
1527 else
1528 audit_log_format(ab, "(null)");
1529 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1530 audit_log_end(ab);
1531 }
1532
1533 /**
1534 * audit_receive_filter - apply all rules to the specified message type
1535 * @type: audit message type
1536 * @pid: target pid for netlink audit messages
1537 * @uid: target uid for netlink audit messages
1538 * @seq: netlink audit message sequence (serial) number
1539 * @data: payload data
1540 * @datasz: size of payload data
1541 * @loginuid: loginuid of sender
1542 * @sid: SE Linux Security ID of sender
1543 */
1544 int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
1545 size_t datasz, uid_t loginuid, u32 sid)
1546 {
1547 struct task_struct *tsk;
1548 struct audit_netlink_list *dest;
1549 int err = 0;
1550 struct audit_entry *entry;
1551
1552 switch (type) {
1553 case AUDIT_LIST:
1554 case AUDIT_LIST_RULES:
1555 /* We can't just spew out the rules here because we might fill
1556 * the available socket buffer space and deadlock waiting for
1557 * auditctl to read from it... which isn't ever going to
1558 * happen if we're actually running in the context of auditctl
1559 * trying to _send_ the stuff */
1560
1561 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1562 if (!dest)
1563 return -ENOMEM;
1564 dest->pid = pid;
1565 skb_queue_head_init(&dest->q);
1566
1567 mutex_lock(&audit_filter_mutex);
1568 if (type == AUDIT_LIST)
1569 audit_list(pid, seq, &dest->q);
1570 else
1571 audit_list_rules(pid, seq, &dest->q);
1572 mutex_unlock(&audit_filter_mutex);
1573
1574 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1575 if (IS_ERR(tsk)) {
1576 skb_queue_purge(&dest->q);
1577 kfree(dest);
1578 err = PTR_ERR(tsk);
1579 }
1580 break;
1581 case AUDIT_ADD:
1582 case AUDIT_ADD_RULE:
1583 if (type == AUDIT_ADD)
1584 entry = audit_rule_to_entry(data);
1585 else
1586 entry = audit_data_to_entry(data, datasz);
1587 if (IS_ERR(entry))
1588 return PTR_ERR(entry);
1589
1590 err = audit_add_rule(entry,
1591 &audit_filter_list[entry->rule.listnr]);
1592 audit_log_rule_change(loginuid, sid, "add", &entry->rule, !err);
1593
1594 if (err)
1595 audit_free_rule(entry);
1596 break;
1597 case AUDIT_DEL:
1598 case AUDIT_DEL_RULE:
1599 if (type == AUDIT_DEL)
1600 entry = audit_rule_to_entry(data);
1601 else
1602 entry = audit_data_to_entry(data, datasz);
1603 if (IS_ERR(entry))
1604 return PTR_ERR(entry);
1605
1606 err = audit_del_rule(entry,
1607 &audit_filter_list[entry->rule.listnr]);
1608 audit_log_rule_change(loginuid, sid, "remove", &entry->rule,
1609 !err);
1610
1611 audit_free_rule(entry);
1612 break;
1613 default:
1614 return -EINVAL;
1615 }
1616
1617 return err;
1618 }
1619
1620 int audit_comparator(const u32 left, const u32 op, const u32 right)
1621 {
1622 switch (op) {
1623 case AUDIT_EQUAL:
1624 return (left == right);
1625 case AUDIT_NOT_EQUAL:
1626 return (left != right);
1627 case AUDIT_LESS_THAN:
1628 return (left < right);
1629 case AUDIT_LESS_THAN_OR_EQUAL:
1630 return (left <= right);
1631 case AUDIT_GREATER_THAN:
1632 return (left > right);
1633 case AUDIT_GREATER_THAN_OR_EQUAL:
1634 return (left >= right);
1635 case AUDIT_BIT_MASK:
1636 return (left & right);
1637 case AUDIT_BIT_TEST:
1638 return ((left & right) == right);
1639 }
1640 BUG();
1641 return 0;
1642 }
1643
1644 /* Compare given dentry name with last component in given path,
1645 * return of 0 indicates a match. */
1646 int audit_compare_dname_path(const char *dname, const char *path,
1647 int *dirlen)
1648 {
1649 int dlen, plen;
1650 const char *p;
1651
1652 if (!dname || !path)
1653 return 1;
1654
1655 dlen = strlen(dname);
1656 plen = strlen(path);
1657 if (plen < dlen)
1658 return 1;
1659
1660 /* disregard trailing slashes */
1661 p = path + plen - 1;
1662 while ((*p == '/') && (p > path))
1663 p--;
1664
1665 /* find last path component */
1666 p = p - dlen + 1;
1667 if (p < path)
1668 return 1;
1669 else if (p > path) {
1670 if (*--p != '/')
1671 return 1;
1672 else
1673 p++;
1674 }
1675
1676 /* return length of path's directory component */
1677 if (dirlen)
1678 *dirlen = p - path;
1679 return strncmp(p, dname, dlen);
1680 }
1681
1682 static int audit_filter_user_rules(struct netlink_skb_parms *cb,
1683 struct audit_krule *rule,
1684 enum audit_state *state)
1685 {
1686 int i;
1687
1688 for (i = 0; i < rule->field_count; i++) {
1689 struct audit_field *f = &rule->fields[i];
1690 int result = 0;
1691
1692 switch (f->type) {
1693 case AUDIT_PID:
1694 result = audit_comparator(cb->creds.pid, f->op, f->val);
1695 break;
1696 case AUDIT_UID:
1697 result = audit_comparator(cb->creds.uid, f->op, f->val);
1698 break;
1699 case AUDIT_GID:
1700 result = audit_comparator(cb->creds.gid, f->op, f->val);
1701 break;
1702 case AUDIT_LOGINUID:
1703 result = audit_comparator(cb->loginuid, f->op, f->val);
1704 break;
1705 }
1706
1707 if (!result)
1708 return 0;
1709 }
1710 switch (rule->action) {
1711 case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
1712 case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
1713 }
1714 return 1;
1715 }
1716
1717 int audit_filter_user(struct netlink_skb_parms *cb, int type)
1718 {
1719 enum audit_state state = AUDIT_DISABLED;
1720 struct audit_entry *e;
1721 int ret = 1;
1722
1723 rcu_read_lock();
1724 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1725 if (audit_filter_user_rules(cb, &e->rule, &state)) {
1726 if (state == AUDIT_DISABLED)
1727 ret = 0;
1728 break;
1729 }
1730 }
1731 rcu_read_unlock();
1732
1733 return ret; /* Audit by default */
1734 }
1735
1736 int audit_filter_type(int type)
1737 {
1738 struct audit_entry *e;
1739 int result = 0;
1740
1741 rcu_read_lock();
1742 if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1743 goto unlock_and_return;
1744
1745 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1746 list) {
1747 int i;
1748 for (i = 0; i < e->rule.field_count; i++) {
1749 struct audit_field *f = &e->rule.fields[i];
1750 if (f->type == AUDIT_MSGTYPE) {
1751 result = audit_comparator(type, f->op, f->val);
1752 if (!result)
1753 break;
1754 }
1755 }
1756 if (result)
1757 goto unlock_and_return;
1758 }
1759 unlock_and_return:
1760 rcu_read_unlock();
1761 return result;
1762 }
1763
1764 /* Check to see if the rule contains any selinux fields. Returns 1 if there
1765 are selinux fields specified in the rule, 0 otherwise. */
1766 static inline int audit_rule_has_selinux(struct audit_krule *rule)
1767 {
1768 int i;
1769
1770 for (i = 0; i < rule->field_count; i++) {
1771 struct audit_field *f = &rule->fields[i];
1772 switch (f->type) {
1773 case AUDIT_SUBJ_USER:
1774 case AUDIT_SUBJ_ROLE:
1775 case AUDIT_SUBJ_TYPE:
1776 case AUDIT_SUBJ_SEN:
1777 case AUDIT_SUBJ_CLR:
1778 case AUDIT_OBJ_USER:
1779 case AUDIT_OBJ_ROLE:
1780 case AUDIT_OBJ_TYPE:
1781 case AUDIT_OBJ_LEV_LOW:
1782 case AUDIT_OBJ_LEV_HIGH:
1783 return 1;
1784 }
1785 }
1786
1787 return 0;
1788 }
1789
1790 /* This function will re-initialize the se_rule field of all applicable rules.
1791 * It will traverse the filter lists serarching for rules that contain selinux
1792 * specific filter fields. When such a rule is found, it is copied, the
1793 * selinux field is re-initialized, and the old rule is replaced with the
1794 * updated rule. */
1795 int selinux_audit_rule_update(void)
1796 {
1797 struct audit_entry *entry, *n, *nentry;
1798 struct audit_watch *watch;
1799 struct audit_tree *tree;
1800 int i, err = 0;
1801
1802 /* audit_filter_mutex synchronizes the writers */
1803 mutex_lock(&audit_filter_mutex);
1804
1805 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1806 list_for_each_entry_safe(entry, n, &audit_filter_list[i], list) {
1807 if (!audit_rule_has_selinux(&entry->rule))
1808 continue;
1809
1810 watch = entry->rule.watch;
1811 tree = entry->rule.tree;
1812 nentry = audit_dupe_rule(&entry->rule, watch);
1813 if (unlikely(IS_ERR(nentry))) {
1814 /* save the first error encountered for the
1815 * return value */
1816 if (!err)
1817 err = PTR_ERR(nentry);
1818 audit_panic("error updating selinux filters");
1819 if (watch)
1820 list_del(&entry->rule.rlist);
1821 list_del_rcu(&entry->list);
1822 } else {
1823 if (watch) {
1824 list_add(&nentry->rule.rlist,
1825 &watch->rules);
1826 list_del(&entry->rule.rlist);
1827 } else if (tree)
1828 list_replace_init(&entry->rule.rlist,
1829 &nentry->rule.rlist);
1830 list_replace_rcu(&entry->list, &nentry->list);
1831 }
1832 call_rcu(&entry->rcu, audit_free_rule_rcu);
1833 }
1834 }
1835
1836 mutex_unlock(&audit_filter_mutex);
1837
1838 return err;
1839 }
1840
1841 /* Update watch data in audit rules based on inotify events. */
1842 void audit_handle_ievent(struct inotify_watch *i_watch, u32 wd, u32 mask,
1843 u32 cookie, const char *dname, struct inode *inode)
1844 {
1845 struct audit_parent *parent;
1846
1847 parent = container_of(i_watch, struct audit_parent, wdata);
1848
1849 if (mask & (IN_CREATE|IN_MOVED_TO) && inode)
1850 audit_update_watch(parent, dname, inode->i_sb->s_dev,
1851 inode->i_ino, 0);
1852 else if (mask & (IN_DELETE|IN_MOVED_FROM))
1853 audit_update_watch(parent, dname, (dev_t)-1, (unsigned long)-1, 1);
1854 /* inotify automatically removes the watch and sends IN_IGNORED */
1855 else if (mask & (IN_DELETE_SELF|IN_UNMOUNT))
1856 audit_remove_parent_watches(parent);
1857 /* inotify does not remove the watch, so remove it manually */
1858 else if(mask & IN_MOVE_SELF) {
1859 audit_remove_parent_watches(parent);
1860 inotify_remove_watch_locked(audit_ih, i_watch);
1861 } else if (mask & IN_IGNORED)
1862 put_inotify_watch(i_watch);
1863 }
WRT350N Kernel Patches