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/security.h>
32 #include "audit.h"
33
34 /*
35 * Locking model:
36 *
37 * audit_filter_mutex:
38 * Synchronizes writes and blocking reads of audit's filterlist
39 * data. Rcu is used to traverse the filterlist and access
40 * contents of structs audit_entry, audit_watch and opaque
41 * LSM rules during filtering. If modified, these structures
42 * must be copied and replace their counterparts in the filterlist.
43 * An audit_parent struct is not accessed during filtering, so may
44 * be written directly provided audit_filter_mutex is held.
45 */
46
47 /*
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 static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
90 LIST_HEAD_INIT(audit_rules_list[0]),
91 LIST_HEAD_INIT(audit_rules_list[1]),
92 LIST_HEAD_INIT(audit_rules_list[2]),
93 LIST_HEAD_INIT(audit_rules_list[3]),
94 LIST_HEAD_INIT(audit_rules_list[4]),
95 LIST_HEAD_INIT(audit_rules_list[5]),
96 };
97
98 DEFINE_MUTEX(audit_filter_mutex);
99
100 /* Inotify events we care about. */
101 #define AUDIT_IN_WATCH IN_MOVE|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF
102
audit_free_parent(struct inotify_watch * i_watch)103 void audit_free_parent(struct inotify_watch *i_watch)
104 {
105 struct audit_parent *parent;
106
107 parent = container_of(i_watch, struct audit_parent, wdata);
108 WARN_ON(!list_empty(&parent->watches));
109 kfree(parent);
110 }
111
audit_get_watch(struct audit_watch * watch)112 static inline void audit_get_watch(struct audit_watch *watch)
113 {
114 atomic_inc(&watch->count);
115 }
116
audit_put_watch(struct audit_watch * watch)117 static void audit_put_watch(struct audit_watch *watch)
118 {
119 if (atomic_dec_and_test(&watch->count)) {
120 WARN_ON(watch->parent);
121 WARN_ON(!list_empty(&watch->rules));
122 kfree(watch->path);
123 kfree(watch);
124 }
125 }
126
audit_remove_watch(struct audit_watch * watch)127 static void audit_remove_watch(struct audit_watch *watch)
128 {
129 list_del(&watch->wlist);
130 put_inotify_watch(&watch->parent->wdata);
131 watch->parent = NULL;
132 audit_put_watch(watch); /* match initial get */
133 }
134
audit_free_rule(struct audit_entry * e)135 static inline void audit_free_rule(struct audit_entry *e)
136 {
137 int i;
138
139 /* some rules don't have associated watches */
140 if (e->rule.watch)
141 audit_put_watch(e->rule.watch);
142 if (e->rule.fields)
143 for (i = 0; i < e->rule.field_count; i++) {
144 struct audit_field *f = &e->rule.fields[i];
145 kfree(f->lsm_str);
146 security_audit_rule_free(f->lsm_rule);
147 }
148 kfree(e->rule.fields);
149 kfree(e->rule.filterkey);
150 kfree(e);
151 }
152
audit_free_rule_rcu(struct rcu_head * head)153 void audit_free_rule_rcu(struct rcu_head *head)
154 {
155 struct audit_entry *e = container_of(head, struct audit_entry, rcu);
156 audit_free_rule(e);
157 }
158
159 /* Initialize a parent watch entry. */
audit_init_parent(struct nameidata * ndp)160 static struct audit_parent *audit_init_parent(struct nameidata *ndp)
161 {
162 struct audit_parent *parent;
163 s32 wd;
164
165 parent = kzalloc(sizeof(*parent), GFP_KERNEL);
166 if (unlikely(!parent))
167 return ERR_PTR(-ENOMEM);
168
169 INIT_LIST_HEAD(&parent->watches);
170 parent->flags = 0;
171
172 inotify_init_watch(&parent->wdata);
173 /* grab a ref so inotify watch hangs around until we take audit_filter_mutex */
174 get_inotify_watch(&parent->wdata);
175 wd = inotify_add_watch(audit_ih, &parent->wdata,
176 ndp->path.dentry->d_inode, AUDIT_IN_WATCH);
177 if (wd < 0) {
178 audit_free_parent(&parent->wdata);
179 return ERR_PTR(wd);
180 }
181
182 return parent;
183 }
184
185 /* Initialize a watch entry. */
audit_init_watch(char * path)186 static struct audit_watch *audit_init_watch(char *path)
187 {
188 struct audit_watch *watch;
189
190 watch = kzalloc(sizeof(*watch), GFP_KERNEL);
191 if (unlikely(!watch))
192 return ERR_PTR(-ENOMEM);
193
194 INIT_LIST_HEAD(&watch->rules);
195 atomic_set(&watch->count, 1);
196 watch->path = path;
197 watch->dev = (dev_t)-1;
198 watch->ino = (unsigned long)-1;
199
200 return watch;
201 }
202
203 /* Initialize an audit filterlist entry. */
audit_init_entry(u32 field_count)204 static inline struct audit_entry *audit_init_entry(u32 field_count)
205 {
206 struct audit_entry *entry;
207 struct audit_field *fields;
208
209 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
210 if (unlikely(!entry))
211 return NULL;
212
213 fields = kzalloc(sizeof(*fields) * field_count, GFP_KERNEL);
214 if (unlikely(!fields)) {
215 kfree(entry);
216 return NULL;
217 }
218 entry->rule.fields = fields;
219
220 return entry;
221 }
222
223 /* Unpack a filter field's string representation from user-space
224 * buffer. */
audit_unpack_string(void ** bufp,size_t * remain,size_t len)225 char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
226 {
227 char *str;
228
229 if (!*bufp || (len == 0) || (len > *remain))
230 return ERR_PTR(-EINVAL);
231
232 /* Of the currently implemented string fields, PATH_MAX
233 * defines the longest valid length.
234 */
235 if (len > PATH_MAX)
236 return ERR_PTR(-ENAMETOOLONG);
237
238 str = kmalloc(len + 1, GFP_KERNEL);
239 if (unlikely(!str))
240 return ERR_PTR(-ENOMEM);
241
242 memcpy(str, *bufp, len);
243 str[len] = 0;
244 *bufp += len;
245 *remain -= len;
246
247 return str;
248 }
249
250 /* Translate an inode field to kernel respresentation. */
audit_to_inode(struct audit_krule * krule,struct audit_field * f)251 static inline int audit_to_inode(struct audit_krule *krule,
252 struct audit_field *f)
253 {
254 if (krule->listnr != AUDIT_FILTER_EXIT ||
255 krule->watch || krule->inode_f || krule->tree ||
256 (f->op != Audit_equal && f->op != Audit_not_equal))
257 return -EINVAL;
258
259 krule->inode_f = f;
260 return 0;
261 }
262
263 /* Translate a watch string to kernel respresentation. */
audit_to_watch(struct audit_krule * krule,char * path,int len,u32 op)264 static int audit_to_watch(struct audit_krule *krule, char *path, int len,
265 u32 op)
266 {
267 struct audit_watch *watch;
268
269 if (!audit_ih)
270 return -EOPNOTSUPP;
271
272 if (path[0] != '/' || path[len-1] == '/' ||
273 krule->listnr != AUDIT_FILTER_EXIT ||
274 op != Audit_equal ||
275 krule->inode_f || krule->watch || krule->tree)
276 return -EINVAL;
277
278 watch = audit_init_watch(path);
279 if (IS_ERR(watch))
280 return PTR_ERR(watch);
281
282 audit_get_watch(watch);
283 krule->watch = watch;
284
285 return 0;
286 }
287
288 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
289
audit_register_class(int class,unsigned * list)290 int __init audit_register_class(int class, unsigned *list)
291 {
292 __u32 *p = kzalloc(AUDIT_BITMASK_SIZE * sizeof(__u32), GFP_KERNEL);
293 if (!p)
294 return -ENOMEM;
295 while (*list != ~0U) {
296 unsigned n = *list++;
297 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
298 kfree(p);
299 return -EINVAL;
300 }
301 p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
302 }
303 if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
304 kfree(p);
305 return -EINVAL;
306 }
307 classes[class] = p;
308 return 0;
309 }
310
audit_match_class(int class,unsigned syscall)311 int audit_match_class(int class, unsigned syscall)
312 {
313 if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
314 return 0;
315 if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
316 return 0;
317 return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
318 }
319
320 #ifdef CONFIG_AUDITSYSCALL
audit_match_class_bits(int class,u32 * mask)321 static inline int audit_match_class_bits(int class, u32 *mask)
322 {
323 int i;
324
325 if (classes[class]) {
326 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
327 if (mask[i] & classes[class][i])
328 return 0;
329 }
330 return 1;
331 }
332
audit_match_signal(struct audit_entry * entry)333 static int audit_match_signal(struct audit_entry *entry)
334 {
335 struct audit_field *arch = entry->rule.arch_f;
336
337 if (!arch) {
338 /* When arch is unspecified, we must check both masks on biarch
339 * as syscall number alone is ambiguous. */
340 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
341 entry->rule.mask) &&
342 audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
343 entry->rule.mask));
344 }
345
346 switch(audit_classify_arch(arch->val)) {
347 case 0: /* native */
348 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
349 entry->rule.mask));
350 case 1: /* 32bit on biarch */
351 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
352 entry->rule.mask));
353 default:
354 return 1;
355 }
356 }
357 #endif
358
359 /* Common user-space to kernel rule translation. */
audit_to_entry_common(struct audit_rule * rule)360 static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule)
361 {
362 unsigned listnr;
363 struct audit_entry *entry;
364 int i, err;
365
366 err = -EINVAL;
367 listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
368 switch(listnr) {
369 default:
370 goto exit_err;
371 case AUDIT_FILTER_USER:
372 case AUDIT_FILTER_TYPE:
373 #ifdef CONFIG_AUDITSYSCALL
374 case AUDIT_FILTER_ENTRY:
375 case AUDIT_FILTER_EXIT:
376 case AUDIT_FILTER_TASK:
377 #endif
378 ;
379 }
380 if (unlikely(rule->action == AUDIT_POSSIBLE)) {
381 printk(KERN_ERR "AUDIT_POSSIBLE is deprecated\n");
382 goto exit_err;
383 }
384 if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
385 goto exit_err;
386 if (rule->field_count > AUDIT_MAX_FIELDS)
387 goto exit_err;
388
389 err = -ENOMEM;
390 entry = audit_init_entry(rule->field_count);
391 if (!entry)
392 goto exit_err;
393
394 entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
395 entry->rule.listnr = listnr;
396 entry->rule.action = rule->action;
397 entry->rule.field_count = rule->field_count;
398
399 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
400 entry->rule.mask[i] = rule->mask[i];
401
402 for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
403 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
404 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
405 __u32 *class;
406
407 if (!(*p & AUDIT_BIT(bit)))
408 continue;
409 *p &= ~AUDIT_BIT(bit);
410 class = classes[i];
411 if (class) {
412 int j;
413 for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
414 entry->rule.mask[j] |= class[j];
415 }
416 }
417
418 return entry;
419
420 exit_err:
421 return ERR_PTR(err);
422 }
423
424 static u32 audit_ops[] =
425 {
426 [Audit_equal] = AUDIT_EQUAL,
427 [Audit_not_equal] = AUDIT_NOT_EQUAL,
428 [Audit_bitmask] = AUDIT_BIT_MASK,
429 [Audit_bittest] = AUDIT_BIT_TEST,
430 [Audit_lt] = AUDIT_LESS_THAN,
431 [Audit_gt] = AUDIT_GREATER_THAN,
432 [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
433 [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
434 };
435
audit_to_op(u32 op)436 static u32 audit_to_op(u32 op)
437 {
438 u32 n;
439 for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
440 ;
441 return n;
442 }
443
444
445 /* Translate struct audit_rule to kernel's rule respresentation.
446 * Exists for backward compatibility with userspace. */
audit_rule_to_entry(struct audit_rule * rule)447 static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
448 {
449 struct audit_entry *entry;
450 int err = 0;
451 int i;
452
453 entry = audit_to_entry_common(rule);
454 if (IS_ERR(entry))
455 goto exit_nofree;
456
457 for (i = 0; i < rule->field_count; i++) {
458 struct audit_field *f = &entry->rule.fields[i];
459 u32 n;
460
461 n = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS);
462
463 /* Support for legacy operators where
464 * AUDIT_NEGATE bit signifies != and otherwise assumes == */
465 if (n & AUDIT_NEGATE)
466 f->op = Audit_not_equal;
467 else if (!n)
468 f->op = Audit_equal;
469 else
470 f->op = audit_to_op(n);
471
472 entry->rule.vers_ops = (n & AUDIT_OPERATORS) ? 2 : 1;
473
474 f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS);
475 f->val = rule->values[i];
476
477 err = -EINVAL;
478 if (f->op == Audit_bad)
479 goto exit_free;
480
481 switch(f->type) {
482 default:
483 goto exit_free;
484 case AUDIT_PID:
485 case AUDIT_UID:
486 case AUDIT_EUID:
487 case AUDIT_SUID:
488 case AUDIT_FSUID:
489 case AUDIT_GID:
490 case AUDIT_EGID:
491 case AUDIT_SGID:
492 case AUDIT_FSGID:
493 case AUDIT_LOGINUID:
494 case AUDIT_PERS:
495 case AUDIT_MSGTYPE:
496 case AUDIT_PPID:
497 case AUDIT_DEVMAJOR:
498 case AUDIT_DEVMINOR:
499 case AUDIT_EXIT:
500 case AUDIT_SUCCESS:
501 /* bit ops are only useful on syscall args */
502 if (f->op == Audit_bitmask || f->op == Audit_bittest)
503 goto exit_free;
504 break;
505 case AUDIT_ARG0:
506 case AUDIT_ARG1:
507 case AUDIT_ARG2:
508 case AUDIT_ARG3:
509 break;
510 /* arch is only allowed to be = or != */
511 case AUDIT_ARCH:
512 if (f->op != Audit_not_equal && f->op != Audit_equal)
513 goto exit_free;
514 entry->rule.arch_f = f;
515 break;
516 case AUDIT_PERM:
517 if (f->val & ~15)
518 goto exit_free;
519 break;
520 case AUDIT_FILETYPE:
521 if ((f->val & ~S_IFMT) > S_IFMT)
522 goto exit_free;
523 break;
524 case AUDIT_INODE:
525 err = audit_to_inode(&entry->rule, f);
526 if (err)
527 goto exit_free;
528 break;
529 }
530 }
531
532 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
533 entry->rule.inode_f = NULL;
534
535 exit_nofree:
536 return entry;
537
538 exit_free:
539 audit_free_rule(entry);
540 return ERR_PTR(err);
541 }
542
543 /* Translate struct audit_rule_data to kernel's rule respresentation. */
audit_data_to_entry(struct audit_rule_data * data,size_t datasz)544 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
545 size_t datasz)
546 {
547 int err = 0;
548 struct audit_entry *entry;
549 void *bufp;
550 size_t remain = datasz - sizeof(struct audit_rule_data);
551 int i;
552 char *str;
553
554 entry = audit_to_entry_common((struct audit_rule *)data);
555 if (IS_ERR(entry))
556 goto exit_nofree;
557
558 bufp = data->buf;
559 entry->rule.vers_ops = 2;
560 for (i = 0; i < data->field_count; i++) {
561 struct audit_field *f = &entry->rule.fields[i];
562
563 err = -EINVAL;
564
565 f->op = audit_to_op(data->fieldflags[i]);
566 if (f->op == Audit_bad)
567 goto exit_free;
568
569 f->type = data->fields[i];
570 f->val = data->values[i];
571 f->lsm_str = NULL;
572 f->lsm_rule = NULL;
573 switch(f->type) {
574 case AUDIT_PID:
575 case AUDIT_UID:
576 case AUDIT_EUID:
577 case AUDIT_SUID:
578 case AUDIT_FSUID:
579 case AUDIT_GID:
580 case AUDIT_EGID:
581 case AUDIT_SGID:
582 case AUDIT_FSGID:
583 case AUDIT_LOGINUID:
584 case AUDIT_PERS:
585 case AUDIT_MSGTYPE:
586 case AUDIT_PPID:
587 case AUDIT_DEVMAJOR:
588 case AUDIT_DEVMINOR:
589 case AUDIT_EXIT:
590 case AUDIT_SUCCESS:
591 case AUDIT_ARG0:
592 case AUDIT_ARG1:
593 case AUDIT_ARG2:
594 case AUDIT_ARG3:
595 break;
596 case AUDIT_ARCH:
597 entry->rule.arch_f = f;
598 break;
599 case AUDIT_SUBJ_USER:
600 case AUDIT_SUBJ_ROLE:
601 case AUDIT_SUBJ_TYPE:
602 case AUDIT_SUBJ_SEN:
603 case AUDIT_SUBJ_CLR:
604 case AUDIT_OBJ_USER:
605 case AUDIT_OBJ_ROLE:
606 case AUDIT_OBJ_TYPE:
607 case AUDIT_OBJ_LEV_LOW:
608 case AUDIT_OBJ_LEV_HIGH:
609 str = audit_unpack_string(&bufp, &remain, f->val);
610 if (IS_ERR(str))
611 goto exit_free;
612 entry->rule.buflen += f->val;
613
614 err = security_audit_rule_init(f->type, f->op, str,
615 (void **)&f->lsm_rule);
616 /* Keep currently invalid fields around in case they
617 * become valid after a policy reload. */
618 if (err == -EINVAL) {
619 printk(KERN_WARNING "audit rule for LSM "
620 "\'%s\' is invalid\n", str);
621 err = 0;
622 }
623 if (err) {
624 kfree(str);
625 goto exit_free;
626 } else
627 f->lsm_str = str;
628 break;
629 case AUDIT_WATCH:
630 str = audit_unpack_string(&bufp, &remain, f->val);
631 if (IS_ERR(str))
632 goto exit_free;
633 entry->rule.buflen += f->val;
634
635 err = audit_to_watch(&entry->rule, str, f->val, f->op);
636 if (err) {
637 kfree(str);
638 goto exit_free;
639 }
640 break;
641 case AUDIT_DIR:
642 str = audit_unpack_string(&bufp, &remain, f->val);
643 if (IS_ERR(str))
644 goto exit_free;
645 entry->rule.buflen += f->val;
646
647 err = audit_make_tree(&entry->rule, str, f->op);
648 kfree(str);
649 if (err)
650 goto exit_free;
651 break;
652 case AUDIT_INODE:
653 err = audit_to_inode(&entry->rule, f);
654 if (err)
655 goto exit_free;
656 break;
657 case AUDIT_FILTERKEY:
658 err = -EINVAL;
659 if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
660 goto exit_free;
661 str = audit_unpack_string(&bufp, &remain, f->val);
662 if (IS_ERR(str))
663 goto exit_free;
664 entry->rule.buflen += f->val;
665 entry->rule.filterkey = str;
666 break;
667 case AUDIT_PERM:
668 if (f->val & ~15)
669 goto exit_free;
670 break;
671 case AUDIT_FILETYPE:
672 if ((f->val & ~S_IFMT) > S_IFMT)
673 goto exit_free;
674 break;
675 default:
676 goto exit_free;
677 }
678 }
679
680 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
681 entry->rule.inode_f = NULL;
682
683 exit_nofree:
684 return entry;
685
686 exit_free:
687 audit_free_rule(entry);
688 return ERR_PTR(err);
689 }
690
691 /* Pack a filter field's string representation into data block. */
audit_pack_string(void ** bufp,const char * str)692 static inline size_t audit_pack_string(void **bufp, const char *str)
693 {
694 size_t len = strlen(str);
695
696 memcpy(*bufp, str, len);
697 *bufp += len;
698
699 return len;
700 }
701
702 /* Translate kernel rule respresentation to struct audit_rule.
703 * Exists for backward compatibility with userspace. */
audit_krule_to_rule(struct audit_krule * krule)704 static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
705 {
706 struct audit_rule *rule;
707 int i;
708
709 rule = kzalloc(sizeof(*rule), GFP_KERNEL);
710 if (unlikely(!rule))
711 return NULL;
712
713 rule->flags = krule->flags | krule->listnr;
714 rule->action = krule->action;
715 rule->field_count = krule->field_count;
716 for (i = 0; i < rule->field_count; i++) {
717 rule->values[i] = krule->fields[i].val;
718 rule->fields[i] = krule->fields[i].type;
719
720 if (krule->vers_ops == 1) {
721 if (krule->fields[i].op == Audit_not_equal)
722 rule->fields[i] |= AUDIT_NEGATE;
723 } else {
724 rule->fields[i] |= audit_ops[krule->fields[i].op];
725 }
726 }
727 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
728
729 return rule;
730 }
731
732 /* Translate kernel rule respresentation to struct audit_rule_data. */
audit_krule_to_data(struct audit_krule * krule)733 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
734 {
735 struct audit_rule_data *data;
736 void *bufp;
737 int i;
738
739 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
740 if (unlikely(!data))
741 return NULL;
742 memset(data, 0, sizeof(*data));
743
744 data->flags = krule->flags | krule->listnr;
745 data->action = krule->action;
746 data->field_count = krule->field_count;
747 bufp = data->buf;
748 for (i = 0; i < data->field_count; i++) {
749 struct audit_field *f = &krule->fields[i];
750
751 data->fields[i] = f->type;
752 data->fieldflags[i] = audit_ops[f->op];
753 switch(f->type) {
754 case AUDIT_SUBJ_USER:
755 case AUDIT_SUBJ_ROLE:
756 case AUDIT_SUBJ_TYPE:
757 case AUDIT_SUBJ_SEN:
758 case AUDIT_SUBJ_CLR:
759 case AUDIT_OBJ_USER:
760 case AUDIT_OBJ_ROLE:
761 case AUDIT_OBJ_TYPE:
762 case AUDIT_OBJ_LEV_LOW:
763 case AUDIT_OBJ_LEV_HIGH:
764 data->buflen += data->values[i] =
765 audit_pack_string(&bufp, f->lsm_str);
766 break;
767 case AUDIT_WATCH:
768 data->buflen += data->values[i] =
769 audit_pack_string(&bufp, krule->watch->path);
770 break;
771 case AUDIT_DIR:
772 data->buflen += data->values[i] =
773 audit_pack_string(&bufp,
774 audit_tree_path(krule->tree));
775 break;
776 case AUDIT_FILTERKEY:
777 data->buflen += data->values[i] =
778 audit_pack_string(&bufp, krule->filterkey);
779 break;
780 default:
781 data->values[i] = f->val;
782 }
783 }
784 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
785
786 return data;
787 }
788
789 /* Compare two rules in kernel format. Considered success if rules
790 * don't match. */
audit_compare_rule(struct audit_krule * a,struct audit_krule * b)791 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
792 {
793 int i;
794
795 if (a->flags != b->flags ||
796 a->listnr != b->listnr ||
797 a->action != b->action ||
798 a->field_count != b->field_count)
799 return 1;
800
801 for (i = 0; i < a->field_count; i++) {
802 if (a->fields[i].type != b->fields[i].type ||
803 a->fields[i].op != b->fields[i].op)
804 return 1;
805
806 switch(a->fields[i].type) {
807 case AUDIT_SUBJ_USER:
808 case AUDIT_SUBJ_ROLE:
809 case AUDIT_SUBJ_TYPE:
810 case AUDIT_SUBJ_SEN:
811 case AUDIT_SUBJ_CLR:
812 case AUDIT_OBJ_USER:
813 case AUDIT_OBJ_ROLE:
814 case AUDIT_OBJ_TYPE:
815 case AUDIT_OBJ_LEV_LOW:
816 case AUDIT_OBJ_LEV_HIGH:
817 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
818 return 1;
819 break;
820 case AUDIT_WATCH:
821 if (strcmp(a->watch->path, b->watch->path))
822 return 1;
823 break;
824 case AUDIT_DIR:
825 if (strcmp(audit_tree_path(a->tree),
826 audit_tree_path(b->tree)))
827 return 1;
828 break;
829 case AUDIT_FILTERKEY:
830 /* both filterkeys exist based on above type compare */
831 if (strcmp(a->filterkey, b->filterkey))
832 return 1;
833 break;
834 default:
835 if (a->fields[i].val != b->fields[i].val)
836 return 1;
837 }
838 }
839
840 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
841 if (a->mask[i] != b->mask[i])
842 return 1;
843
844 return 0;
845 }
846
847 /* Duplicate the given audit watch. The new watch's rules list is initialized
848 * to an empty list and wlist is undefined. */
audit_dupe_watch(struct audit_watch * old)849 static struct audit_watch *audit_dupe_watch(struct audit_watch *old)
850 {
851 char *path;
852 struct audit_watch *new;
853
854 path = kstrdup(old->path, GFP_KERNEL);
855 if (unlikely(!path))
856 return ERR_PTR(-ENOMEM);
857
858 new = audit_init_watch(path);
859 if (IS_ERR(new)) {
860 kfree(path);
861 goto out;
862 }
863
864 new->dev = old->dev;
865 new->ino = old->ino;
866 get_inotify_watch(&old->parent->wdata);
867 new->parent = old->parent;
868
869 out:
870 return new;
871 }
872
873 /* Duplicate LSM field information. The lsm_rule is opaque, so must be
874 * re-initialized. */
audit_dupe_lsm_field(struct audit_field * df,struct audit_field * sf)875 static inline int audit_dupe_lsm_field(struct audit_field *df,
876 struct audit_field *sf)
877 {
878 int ret = 0;
879 char *lsm_str;
880
881 /* our own copy of lsm_str */
882 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
883 if (unlikely(!lsm_str))
884 return -ENOMEM;
885 df->lsm_str = lsm_str;
886
887 /* our own (refreshed) copy of lsm_rule */
888 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
889 (void **)&df->lsm_rule);
890 /* Keep currently invalid fields around in case they
891 * become valid after a policy reload. */
892 if (ret == -EINVAL) {
893 printk(KERN_WARNING "audit rule for LSM \'%s\' is "
894 "invalid\n", df->lsm_str);
895 ret = 0;
896 }
897
898 return ret;
899 }
900
901 /* Duplicate an audit rule. This will be a deep copy with the exception
902 * of the watch - that pointer is carried over. The LSM specific fields
903 * will be updated in the copy. The point is to be able to replace the old
904 * rule with the new rule in the filterlist, then free the old rule.
905 * The rlist element is undefined; list manipulations are handled apart from
906 * the initial copy. */
audit_dupe_rule(struct audit_krule * old,struct audit_watch * watch)907 static struct audit_entry *audit_dupe_rule(struct audit_krule *old,
908 struct audit_watch *watch)
909 {
910 u32 fcount = old->field_count;
911 struct audit_entry *entry;
912 struct audit_krule *new;
913 char *fk;
914 int i, err = 0;
915
916 entry = audit_init_entry(fcount);
917 if (unlikely(!entry))
918 return ERR_PTR(-ENOMEM);
919
920 new = &entry->rule;
921 new->vers_ops = old->vers_ops;
922 new->flags = old->flags;
923 new->listnr = old->listnr;
924 new->action = old->action;
925 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
926 new->mask[i] = old->mask[i];
927 new->prio = old->prio;
928 new->buflen = old->buflen;
929 new->inode_f = old->inode_f;
930 new->watch = NULL;
931 new->field_count = old->field_count;
932 /*
933 * note that we are OK with not refcounting here; audit_match_tree()
934 * never dereferences tree and we can't get false positives there
935 * since we'd have to have rule gone from the list *and* removed
936 * before the chunks found by lookup had been allocated, i.e. before
937 * the beginning of list scan.
938 */
939 new->tree = old->tree;
940 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
941
942 /* deep copy this information, updating the lsm_rule fields, because
943 * the originals will all be freed when the old rule is freed. */
944 for (i = 0; i < fcount; i++) {
945 switch (new->fields[i].type) {
946 case AUDIT_SUBJ_USER:
947 case AUDIT_SUBJ_ROLE:
948 case AUDIT_SUBJ_TYPE:
949 case AUDIT_SUBJ_SEN:
950 case AUDIT_SUBJ_CLR:
951 case AUDIT_OBJ_USER:
952 case AUDIT_OBJ_ROLE:
953 case AUDIT_OBJ_TYPE:
954 case AUDIT_OBJ_LEV_LOW:
955 case AUDIT_OBJ_LEV_HIGH:
956 err = audit_dupe_lsm_field(&new->fields[i],
957 &old->fields[i]);
958 break;
959 case AUDIT_FILTERKEY:
960 fk = kstrdup(old->filterkey, GFP_KERNEL);
961 if (unlikely(!fk))
962 err = -ENOMEM;
963 else
964 new->filterkey = fk;
965 }
966 if (err) {
967 audit_free_rule(entry);
968 return ERR_PTR(err);
969 }
970 }
971
972 if (watch) {
973 audit_get_watch(watch);
974 new->watch = watch;
975 }
976
977 return entry;
978 }
979
980 /* Update inode info in audit rules based on filesystem event. */
audit_update_watch(struct audit_parent * parent,const char * dname,dev_t dev,unsigned long ino,unsigned invalidating)981 static void audit_update_watch(struct audit_parent *parent,
982 const char *dname, dev_t dev,
983 unsigned long ino, unsigned invalidating)
984 {
985 struct audit_watch *owatch, *nwatch, *nextw;
986 struct audit_krule *r, *nextr;
987 struct audit_entry *oentry, *nentry;
988
989 mutex_lock(&audit_filter_mutex);
990 list_for_each_entry_safe(owatch, nextw, &parent->watches, wlist) {
991 if (audit_compare_dname_path(dname, owatch->path, NULL))
992 continue;
993
994 /* If the update involves invalidating rules, do the inode-based
995 * filtering now, so we don't omit records. */
996 if (invalidating && current->audit_context)
997 audit_filter_inodes(current, current->audit_context);
998
999 nwatch = audit_dupe_watch(owatch);
1000 if (IS_ERR(nwatch)) {
1001 mutex_unlock(&audit_filter_mutex);
1002 audit_panic("error updating watch, skipping");
1003 return;
1004 }
1005 nwatch->dev = dev;
1006 nwatch->ino = ino;
1007
1008 list_for_each_entry_safe(r, nextr, &owatch->rules, rlist) {
1009
1010 oentry = container_of(r, struct audit_entry, rule);
1011 list_del(&oentry->rule.rlist);
1012 list_del_rcu(&oentry->list);
1013
1014 nentry = audit_dupe_rule(&oentry->rule, nwatch);
1015 if (IS_ERR(nentry)) {
1016 list_del(&oentry->rule.list);
1017 audit_panic("error updating watch, removing");
1018 } else {
1019 int h = audit_hash_ino((u32)ino);
1020 list_add(&nentry->rule.rlist, &nwatch->rules);
1021 list_add_rcu(&nentry->list, &audit_inode_hash[h]);
1022 list_replace(&oentry->rule.list,
1023 &nentry->rule.list);
1024 }
1025
1026 call_rcu(&oentry->rcu, audit_free_rule_rcu);
1027 }
1028
1029 if (audit_enabled) {
1030 struct audit_buffer *ab;
1031 ab = audit_log_start(NULL, GFP_KERNEL,
1032 AUDIT_CONFIG_CHANGE);
1033 audit_log_format(ab, "auid=%u ses=%u",
1034 audit_get_loginuid(current),
1035 audit_get_sessionid(current));
1036 audit_log_format(ab,
1037 " op=updated rules specifying path=");
1038 audit_log_untrustedstring(ab, owatch->path);
1039 audit_log_format(ab, " with dev=%u ino=%lu\n",
1040 dev, ino);
1041 audit_log_format(ab, " list=%d res=1", r->listnr);
1042 audit_log_end(ab);
1043 }
1044 audit_remove_watch(owatch);
1045 goto add_watch_to_parent; /* event applies to a single watch */
1046 }
1047 mutex_unlock(&audit_filter_mutex);
1048 return;
1049
1050 add_watch_to_parent:
1051 list_add(&nwatch->wlist, &parent->watches);
1052 mutex_unlock(&audit_filter_mutex);
1053 return;
1054 }
1055
1056 /* Remove all watches & rules associated with a parent that is going away. */
audit_remove_parent_watches(struct audit_parent * parent)1057 static void audit_remove_parent_watches(struct audit_parent *parent)
1058 {
1059 struct audit_watch *w, *nextw;
1060 struct audit_krule *r, *nextr;
1061 struct audit_entry *e;
1062
1063 mutex_lock(&audit_filter_mutex);
1064 parent->flags |= AUDIT_PARENT_INVALID;
1065 list_for_each_entry_safe(w, nextw, &parent->watches, wlist) {
1066 list_for_each_entry_safe(r, nextr, &w->rules, rlist) {
1067 e = container_of(r, struct audit_entry, rule);
1068 if (audit_enabled) {
1069 struct audit_buffer *ab;
1070 ab = audit_log_start(NULL, GFP_KERNEL,
1071 AUDIT_CONFIG_CHANGE);
1072 audit_log_format(ab, "auid=%u ses=%u",
1073 audit_get_loginuid(current),
1074 audit_get_sessionid(current));
1075 audit_log_format(ab, " op=remove rule path=");
1076 audit_log_untrustedstring(ab, w->path);
1077 if (r->filterkey) {
1078 audit_log_format(ab, " key=");
1079 audit_log_untrustedstring(ab,
1080 r->filterkey);
1081 } else
1082 audit_log_format(ab, " key=(null)");
1083 audit_log_format(ab, " list=%d res=1",
1084 r->listnr);
1085 audit_log_end(ab);
1086 }
1087 list_del(&r->rlist);
1088 list_del(&r->list);
1089 list_del_rcu(&e->list);
1090 call_rcu(&e->rcu, audit_free_rule_rcu);
1091 }
1092 audit_remove_watch(w);
1093 }
1094 mutex_unlock(&audit_filter_mutex);
1095 }
1096
1097 /* Unregister inotify watches for parents on in_list.
1098 * Generates an IN_IGNORED event. */
audit_inotify_unregister(struct list_head * in_list)1099 static void audit_inotify_unregister(struct list_head *in_list)
1100 {
1101 struct audit_parent *p, *n;
1102
1103 list_for_each_entry_safe(p, n, in_list, ilist) {
1104 list_del(&p->ilist);
1105 inotify_rm_watch(audit_ih, &p->wdata);
1106 /* the unpin matching the pin in audit_do_del_rule() */
1107 unpin_inotify_watch(&p->wdata);
1108 }
1109 }
1110
1111 /* Find an existing audit rule.
1112 * Caller must hold audit_filter_mutex to prevent stale rule data. */
audit_find_rule(struct audit_entry * entry,struct list_head ** p)1113 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
1114 struct list_head **p)
1115 {
1116 struct audit_entry *e, *found = NULL;
1117 struct list_head *list;
1118 int h;
1119
1120 if (entry->rule.inode_f) {
1121 h = audit_hash_ino(entry->rule.inode_f->val);
1122 *p = list = &audit_inode_hash[h];
1123 } else if (entry->rule.watch) {
1124 /* we don't know the inode number, so must walk entire hash */
1125 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
1126 list = &audit_inode_hash[h];
1127 list_for_each_entry(e, list, list)
1128 if (!audit_compare_rule(&entry->rule, &e->rule)) {
1129 found = e;
1130 goto out;
1131 }
1132 }
1133 goto out;
1134 } else {
1135 *p = list = &audit_filter_list[entry->rule.listnr];
1136 }
1137
1138 list_for_each_entry(e, list, list)
1139 if (!audit_compare_rule(&entry->rule, &e->rule)) {
1140 found = e;
1141 goto out;
1142 }
1143
1144 out:
1145 return found;
1146 }
1147
1148 /* Get path information necessary for adding watches. */
audit_get_nd(char * path,struct nameidata ** ndp,struct nameidata ** ndw)1149 static int audit_get_nd(char *path, struct nameidata **ndp,
1150 struct nameidata **ndw)
1151 {
1152 struct nameidata *ndparent, *ndwatch;
1153 int err;
1154
1155 ndparent = kmalloc(sizeof(*ndparent), GFP_KERNEL);
1156 if (unlikely(!ndparent))
1157 return -ENOMEM;
1158
1159 ndwatch = kmalloc(sizeof(*ndwatch), GFP_KERNEL);
1160 if (unlikely(!ndwatch)) {
1161 kfree(ndparent);
1162 return -ENOMEM;
1163 }
1164
1165 err = path_lookup(path, LOOKUP_PARENT, ndparent);
1166 if (err) {
1167 kfree(ndparent);
1168 kfree(ndwatch);
1169 return err;
1170 }
1171
1172 err = path_lookup(path, 0, ndwatch);
1173 if (err) {
1174 kfree(ndwatch);
1175 ndwatch = NULL;
1176 }
1177
1178 *ndp = ndparent;
1179 *ndw = ndwatch;
1180
1181 return 0;
1182 }
1183
1184 /* Release resources used for watch path information. */
audit_put_nd(struct nameidata * ndp,struct nameidata * ndw)1185 static void audit_put_nd(struct nameidata *ndp, struct nameidata *ndw)
1186 {
1187 if (ndp) {
1188 path_put(&ndp->path);
1189 kfree(ndp);
1190 }
1191 if (ndw) {
1192 path_put(&ndw->path);
1193 kfree(ndw);
1194 }
1195 }
1196
1197 /* Associate the given rule with an existing parent inotify_watch.
1198 * Caller must hold audit_filter_mutex. */
audit_add_to_parent(struct audit_krule * krule,struct audit_parent * parent)1199 static void audit_add_to_parent(struct audit_krule *krule,
1200 struct audit_parent *parent)
1201 {
1202 struct audit_watch *w, *watch = krule->watch;
1203 int watch_found = 0;
1204
1205 list_for_each_entry(w, &parent->watches, wlist) {
1206 if (strcmp(watch->path, w->path))
1207 continue;
1208
1209 watch_found = 1;
1210
1211 /* put krule's and initial refs to temporary watch */
1212 audit_put_watch(watch);
1213 audit_put_watch(watch);
1214
1215 audit_get_watch(w);
1216 krule->watch = watch = w;
1217 break;
1218 }
1219
1220 if (!watch_found) {
1221 get_inotify_watch(&parent->wdata);
1222 watch->parent = parent;
1223
1224 list_add(&watch->wlist, &parent->watches);
1225 }
1226 list_add(&krule->rlist, &watch->rules);
1227 }
1228
1229 /* Find a matching watch entry, or add this one.
1230 * Caller must hold audit_filter_mutex. */
audit_add_watch(struct audit_krule * krule,struct nameidata * ndp,struct nameidata * ndw)1231 static int audit_add_watch(struct audit_krule *krule, struct nameidata *ndp,
1232 struct nameidata *ndw)
1233 {
1234 struct audit_watch *watch = krule->watch;
1235 struct inotify_watch *i_watch;
1236 struct audit_parent *parent;
1237 int ret = 0;
1238
1239 /* update watch filter fields */
1240 if (ndw) {
1241 watch->dev = ndw->path.dentry->d_inode->i_sb->s_dev;
1242 watch->ino = ndw->path.dentry->d_inode->i_ino;
1243 }
1244
1245 /* The audit_filter_mutex must not be held during inotify calls because
1246 * we hold it during inotify event callback processing. If an existing
1247 * inotify watch is found, inotify_find_watch() grabs a reference before
1248 * returning.
1249 */
1250 mutex_unlock(&audit_filter_mutex);
1251
1252 if (inotify_find_watch(audit_ih, ndp->path.dentry->d_inode,
1253 &i_watch) < 0) {
1254 parent = audit_init_parent(ndp);
1255 if (IS_ERR(parent)) {
1256 /* caller expects mutex locked */
1257 mutex_lock(&audit_filter_mutex);
1258 return PTR_ERR(parent);
1259 }
1260 } else
1261 parent = container_of(i_watch, struct audit_parent, wdata);
1262
1263 mutex_lock(&audit_filter_mutex);
1264
1265 /* parent was moved before we took audit_filter_mutex */
1266 if (parent->flags & AUDIT_PARENT_INVALID)
1267 ret = -ENOENT;
1268 else
1269 audit_add_to_parent(krule, parent);
1270
1271 /* match get in audit_init_parent or inotify_find_watch */
1272 put_inotify_watch(&parent->wdata);
1273 return ret;
1274 }
1275
1276 static u64 prio_low = ~0ULL/2;
1277 static u64 prio_high = ~0ULL/2 - 1;
1278
1279 /* Add rule to given filterlist if not a duplicate. */
audit_add_rule(struct audit_entry * entry)1280 static inline int audit_add_rule(struct audit_entry *entry)
1281 {
1282 struct audit_entry *e;
1283 struct audit_watch *watch = entry->rule.watch;
1284 struct audit_tree *tree = entry->rule.tree;
1285 struct nameidata *ndp = NULL, *ndw = NULL;
1286 struct list_head *list;
1287 int h, err;
1288 #ifdef CONFIG_AUDITSYSCALL
1289 int dont_count = 0;
1290
1291 /* If either of these, don't count towards total */
1292 if (entry->rule.listnr == AUDIT_FILTER_USER ||
1293 entry->rule.listnr == AUDIT_FILTER_TYPE)
1294 dont_count = 1;
1295 #endif
1296
1297 mutex_lock(&audit_filter_mutex);
1298 e = audit_find_rule(entry, &list);
1299 mutex_unlock(&audit_filter_mutex);
1300 if (e) {
1301 err = -EEXIST;
1302 /* normally audit_add_tree_rule() will free it on failure */
1303 if (tree)
1304 audit_put_tree(tree);
1305 goto error;
1306 }
1307
1308 /* Avoid calling path_lookup under audit_filter_mutex. */
1309 if (watch) {
1310 err = audit_get_nd(watch->path, &ndp, &ndw);
1311 if (err)
1312 goto error;
1313 }
1314
1315 mutex_lock(&audit_filter_mutex);
1316 if (watch) {
1317 /* audit_filter_mutex is dropped and re-taken during this call */
1318 err = audit_add_watch(&entry->rule, ndp, ndw);
1319 if (err) {
1320 mutex_unlock(&audit_filter_mutex);
1321 goto error;
1322 }
1323 h = audit_hash_ino((u32)watch->ino);
1324 list = &audit_inode_hash[h];
1325 }
1326 if (tree) {
1327 err = audit_add_tree_rule(&entry->rule);
1328 if (err) {
1329 mutex_unlock(&audit_filter_mutex);
1330 goto error;
1331 }
1332 }
1333
1334 entry->rule.prio = ~0ULL;
1335 if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
1336 if (entry->rule.flags & AUDIT_FILTER_PREPEND)
1337 entry->rule.prio = ++prio_high;
1338 else
1339 entry->rule.prio = --prio_low;
1340 }
1341
1342 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
1343 list_add(&entry->rule.list,
1344 &audit_rules_list[entry->rule.listnr]);
1345 list_add_rcu(&entry->list, list);
1346 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
1347 } else {
1348 list_add_tail(&entry->rule.list,
1349 &audit_rules_list[entry->rule.listnr]);
1350 list_add_tail_rcu(&entry->list, list);
1351 }
1352 #ifdef CONFIG_AUDITSYSCALL
1353 if (!dont_count)
1354 audit_n_rules++;
1355
1356 if (!audit_match_signal(entry))
1357 audit_signals++;
1358 #endif
1359 mutex_unlock(&audit_filter_mutex);
1360
1361 audit_put_nd(ndp, ndw); /* NULL args OK */
1362 return 0;
1363
1364 error:
1365 audit_put_nd(ndp, ndw); /* NULL args OK */
1366 if (watch)
1367 audit_put_watch(watch); /* tmp watch, matches initial get */
1368 return err;
1369 }
1370
1371 /* Remove an existing rule from filterlist. */
audit_del_rule(struct audit_entry * entry)1372 static inline int audit_del_rule(struct audit_entry *entry)
1373 {
1374 struct audit_entry *e;
1375 struct audit_watch *watch, *tmp_watch = entry->rule.watch;
1376 struct audit_tree *tree = entry->rule.tree;
1377 struct list_head *list;
1378 LIST_HEAD(inotify_list);
1379 int ret = 0;
1380 #ifdef CONFIG_AUDITSYSCALL
1381 int dont_count = 0;
1382
1383 /* If either of these, don't count towards total */
1384 if (entry->rule.listnr == AUDIT_FILTER_USER ||
1385 entry->rule.listnr == AUDIT_FILTER_TYPE)
1386 dont_count = 1;
1387 #endif
1388
1389 mutex_lock(&audit_filter_mutex);
1390 e = audit_find_rule(entry, &list);
1391 if (!e) {
1392 mutex_unlock(&audit_filter_mutex);
1393 ret = -ENOENT;
1394 goto out;
1395 }
1396
1397 watch = e->rule.watch;
1398 if (watch) {
1399 struct audit_parent *parent = watch->parent;
1400
1401 list_del(&e->rule.rlist);
1402
1403 if (list_empty(&watch->rules)) {
1404 audit_remove_watch(watch);
1405
1406 if (list_empty(&parent->watches)) {
1407 /* Put parent on the inotify un-registration
1408 * list. Grab a reference before releasing
1409 * audit_filter_mutex, to be released in
1410 * audit_inotify_unregister().
1411 * If filesystem is going away, just leave
1412 * the sucker alone, eviction will take
1413 * care of it.
1414 */
1415 if (pin_inotify_watch(&parent->wdata))
1416 list_add(&parent->ilist, &inotify_list);
1417 }
1418 }
1419 }
1420
1421 if (e->rule.tree)
1422 audit_remove_tree_rule(&e->rule);
1423
1424 list_del_rcu(&e->list);
1425 list_del(&e->rule.list);
1426 call_rcu(&e->rcu, audit_free_rule_rcu);
1427
1428 #ifdef CONFIG_AUDITSYSCALL
1429 if (!dont_count)
1430 audit_n_rules--;
1431
1432 if (!audit_match_signal(entry))
1433 audit_signals--;
1434 #endif
1435 mutex_unlock(&audit_filter_mutex);
1436
1437 if (!list_empty(&inotify_list))
1438 audit_inotify_unregister(&inotify_list);
1439
1440 out:
1441 if (tmp_watch)
1442 audit_put_watch(tmp_watch); /* match initial get */
1443 if (tree)
1444 audit_put_tree(tree); /* that's the temporary one */
1445
1446 return ret;
1447 }
1448
1449 /* List rules using struct audit_rule. Exists for backward
1450 * compatibility with userspace. */
audit_list(int pid,int seq,struct sk_buff_head * q)1451 static void audit_list(int pid, int seq, struct sk_buff_head *q)
1452 {
1453 struct sk_buff *skb;
1454 struct audit_krule *r;
1455 int i;
1456
1457 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1458 * iterator to sync with list writers. */
1459 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1460 list_for_each_entry(r, &audit_rules_list[i], list) {
1461 struct audit_rule *rule;
1462
1463 rule = audit_krule_to_rule(r);
1464 if (unlikely(!rule))
1465 break;
1466 skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1467 rule, sizeof(*rule));
1468 if (skb)
1469 skb_queue_tail(q, skb);
1470 kfree(rule);
1471 }
1472 }
1473 skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
1474 if (skb)
1475 skb_queue_tail(q, skb);
1476 }
1477
1478 /* List rules using struct audit_rule_data. */
audit_list_rules(int pid,int seq,struct sk_buff_head * q)1479 static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
1480 {
1481 struct sk_buff *skb;
1482 struct audit_krule *r;
1483 int i;
1484
1485 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1486 * iterator to sync with list writers. */
1487 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1488 list_for_each_entry(r, &audit_rules_list[i], list) {
1489 struct audit_rule_data *data;
1490
1491 data = audit_krule_to_data(r);
1492 if (unlikely(!data))
1493 break;
1494 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1495 data, sizeof(*data) + data->buflen);
1496 if (skb)
1497 skb_queue_tail(q, skb);
1498 kfree(data);
1499 }
1500 }
1501 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1502 if (skb)
1503 skb_queue_tail(q, skb);
1504 }
1505
1506 /* Log rule additions and removals */
audit_log_rule_change(uid_t loginuid,u32 sessionid,u32 sid,char * action,struct audit_krule * rule,int res)1507 static void audit_log_rule_change(uid_t loginuid, u32 sessionid, u32 sid,
1508 char *action, struct audit_krule *rule,
1509 int res)
1510 {
1511 struct audit_buffer *ab;
1512
1513 if (!audit_enabled)
1514 return;
1515
1516 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1517 if (!ab)
1518 return;
1519 audit_log_format(ab, "auid=%u ses=%u", loginuid, sessionid);
1520 if (sid) {
1521 char *ctx = NULL;
1522 u32 len;
1523 if (security_secid_to_secctx(sid, &ctx, &len))
1524 audit_log_format(ab, " ssid=%u", sid);
1525 else {
1526 audit_log_format(ab, " subj=%s", ctx);
1527 security_release_secctx(ctx, len);
1528 }
1529 }
1530 audit_log_format(ab, " op=%s rule key=", action);
1531 if (rule->filterkey)
1532 audit_log_untrustedstring(ab, rule->filterkey);
1533 else
1534 audit_log_format(ab, "(null)");
1535 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1536 audit_log_end(ab);
1537 }
1538
1539 /**
1540 * audit_receive_filter - apply all rules to the specified message type
1541 * @type: audit message type
1542 * @pid: target pid for netlink audit messages
1543 * @uid: target uid for netlink audit messages
1544 * @seq: netlink audit message sequence (serial) number
1545 * @data: payload data
1546 * @datasz: size of payload data
1547 * @loginuid: loginuid of sender
1548 * @sessionid: sessionid for netlink audit message
1549 * @sid: SE Linux Security ID of sender
1550 */
audit_receive_filter(int type,int pid,int uid,int seq,void * data,size_t datasz,uid_t loginuid,u32 sessionid,u32 sid)1551 int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
1552 size_t datasz, uid_t loginuid, u32 sessionid, u32 sid)
1553 {
1554 struct task_struct *tsk;
1555 struct audit_netlink_list *dest;
1556 int err = 0;
1557 struct audit_entry *entry;
1558
1559 switch (type) {
1560 case AUDIT_LIST:
1561 case AUDIT_LIST_RULES:
1562 /* We can't just spew out the rules here because we might fill
1563 * the available socket buffer space and deadlock waiting for
1564 * auditctl to read from it... which isn't ever going to
1565 * happen if we're actually running in the context of auditctl
1566 * trying to _send_ the stuff */
1567
1568 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1569 if (!dest)
1570 return -ENOMEM;
1571 dest->pid = pid;
1572 skb_queue_head_init(&dest->q);
1573
1574 mutex_lock(&audit_filter_mutex);
1575 if (type == AUDIT_LIST)
1576 audit_list(pid, seq, &dest->q);
1577 else
1578 audit_list_rules(pid, seq, &dest->q);
1579 mutex_unlock(&audit_filter_mutex);
1580
1581 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1582 if (IS_ERR(tsk)) {
1583 skb_queue_purge(&dest->q);
1584 kfree(dest);
1585 err = PTR_ERR(tsk);
1586 }
1587 break;
1588 case AUDIT_ADD:
1589 case AUDIT_ADD_RULE:
1590 if (type == AUDIT_ADD)
1591 entry = audit_rule_to_entry(data);
1592 else
1593 entry = audit_data_to_entry(data, datasz);
1594 if (IS_ERR(entry))
1595 return PTR_ERR(entry);
1596
1597 err = audit_add_rule(entry);
1598 audit_log_rule_change(loginuid, sessionid, sid, "add",
1599 &entry->rule, !err);
1600
1601 if (err)
1602 audit_free_rule(entry);
1603 break;
1604 case AUDIT_DEL:
1605 case AUDIT_DEL_RULE:
1606 if (type == AUDIT_DEL)
1607 entry = audit_rule_to_entry(data);
1608 else
1609 entry = audit_data_to_entry(data, datasz);
1610 if (IS_ERR(entry))
1611 return PTR_ERR(entry);
1612
1613 err = audit_del_rule(entry);
1614 audit_log_rule_change(loginuid, sessionid, sid, "remove",
1615 &entry->rule, !err);
1616
1617 audit_free_rule(entry);
1618 break;
1619 default:
1620 return -EINVAL;
1621 }
1622
1623 return err;
1624 }
1625
audit_comparator(u32 left,u32 op,u32 right)1626 int audit_comparator(u32 left, u32 op, u32 right)
1627 {
1628 switch (op) {
1629 case Audit_equal:
1630 return (left == right);
1631 case Audit_not_equal:
1632 return (left != right);
1633 case Audit_lt:
1634 return (left < right);
1635 case Audit_le:
1636 return (left <= right);
1637 case Audit_gt:
1638 return (left > right);
1639 case Audit_ge:
1640 return (left >= right);
1641 case Audit_bitmask:
1642 return (left & right);
1643 case Audit_bittest:
1644 return ((left & right) == right);
1645 default:
1646 BUG();
1647 return 0;
1648 }
1649 }
1650
1651 /* Compare given dentry name with last component in given path,
1652 * return of 0 indicates a match. */
audit_compare_dname_path(const char * dname,const char * path,int * dirlen)1653 int audit_compare_dname_path(const char *dname, const char *path,
1654 int *dirlen)
1655 {
1656 int dlen, plen;
1657 const char *p;
1658
1659 if (!dname || !path)
1660 return 1;
1661
1662 dlen = strlen(dname);
1663 plen = strlen(path);
1664 if (plen < dlen)
1665 return 1;
1666
1667 /* disregard trailing slashes */
1668 p = path + plen - 1;
1669 while ((*p == '/') && (p > path))
1670 p--;
1671
1672 /* find last path component */
1673 p = p - dlen + 1;
1674 if (p < path)
1675 return 1;
1676 else if (p > path) {
1677 if (*--p != '/')
1678 return 1;
1679 else
1680 p++;
1681 }
1682
1683 /* return length of path's directory component */
1684 if (dirlen)
1685 *dirlen = p - path;
1686 return strncmp(p, dname, dlen);
1687 }
1688
audit_filter_user_rules(struct netlink_skb_parms * cb,struct audit_krule * rule,enum audit_state * state)1689 static int audit_filter_user_rules(struct netlink_skb_parms *cb,
1690 struct audit_krule *rule,
1691 enum audit_state *state)
1692 {
1693 int i;
1694
1695 for (i = 0; i < rule->field_count; i++) {
1696 struct audit_field *f = &rule->fields[i];
1697 int result = 0;
1698
1699 switch (f->type) {
1700 case AUDIT_PID:
1701 result = audit_comparator(cb->creds.pid, f->op, f->val);
1702 break;
1703 case AUDIT_UID:
1704 result = audit_comparator(cb->creds.uid, f->op, f->val);
1705 break;
1706 case AUDIT_GID:
1707 result = audit_comparator(cb->creds.gid, f->op, f->val);
1708 break;
1709 case AUDIT_LOGINUID:
1710 result = audit_comparator(cb->loginuid, f->op, f->val);
1711 break;
1712 }
1713
1714 if (!result)
1715 return 0;
1716 }
1717 switch (rule->action) {
1718 case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
1719 case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
1720 }
1721 return 1;
1722 }
1723
audit_filter_user(struct netlink_skb_parms * cb)1724 int audit_filter_user(struct netlink_skb_parms *cb)
1725 {
1726 enum audit_state state = AUDIT_DISABLED;
1727 struct audit_entry *e;
1728 int ret = 1;
1729
1730 rcu_read_lock();
1731 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1732 if (audit_filter_user_rules(cb, &e->rule, &state)) {
1733 if (state == AUDIT_DISABLED)
1734 ret = 0;
1735 break;
1736 }
1737 }
1738 rcu_read_unlock();
1739
1740 return ret; /* Audit by default */
1741 }
1742
audit_filter_type(int type)1743 int audit_filter_type(int type)
1744 {
1745 struct audit_entry *e;
1746 int result = 0;
1747
1748 rcu_read_lock();
1749 if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1750 goto unlock_and_return;
1751
1752 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1753 list) {
1754 int i;
1755 for (i = 0; i < e->rule.field_count; i++) {
1756 struct audit_field *f = &e->rule.fields[i];
1757 if (f->type == AUDIT_MSGTYPE) {
1758 result = audit_comparator(type, f->op, f->val);
1759 if (!result)
1760 break;
1761 }
1762 }
1763 if (result)
1764 goto unlock_and_return;
1765 }
1766 unlock_and_return:
1767 rcu_read_unlock();
1768 return result;
1769 }
1770
update_lsm_rule(struct audit_krule * r)1771 static int update_lsm_rule(struct audit_krule *r)
1772 {
1773 struct audit_entry *entry = container_of(r, struct audit_entry, rule);
1774 struct audit_entry *nentry;
1775 struct audit_watch *watch;
1776 struct audit_tree *tree;
1777 int err = 0;
1778
1779 if (!security_audit_rule_known(r))
1780 return 0;
1781
1782 watch = r->watch;
1783 tree = r->tree;
1784 nentry = audit_dupe_rule(r, watch);
1785 if (IS_ERR(nentry)) {
1786 /* save the first error encountered for the
1787 * return value */
1788 err = PTR_ERR(nentry);
1789 audit_panic("error updating LSM filters");
1790 if (watch)
1791 list_del(&r->rlist);
1792 list_del_rcu(&entry->list);
1793 list_del(&r->list);
1794 } else {
1795 if (watch) {
1796 list_add(&nentry->rule.rlist, &watch->rules);
1797 list_del(&r->rlist);
1798 } else if (tree)
1799 list_replace_init(&r->rlist, &nentry->rule.rlist);
1800 list_replace_rcu(&entry->list, &nentry->list);
1801 list_replace(&r->list, &nentry->rule.list);
1802 }
1803 call_rcu(&entry->rcu, audit_free_rule_rcu);
1804
1805 return err;
1806 }
1807
1808 /* This function will re-initialize the lsm_rule field of all applicable rules.
1809 * It will traverse the filter lists serarching for rules that contain LSM
1810 * specific filter fields. When such a rule is found, it is copied, the
1811 * LSM field is re-initialized, and the old rule is replaced with the
1812 * updated rule. */
audit_update_lsm_rules(void)1813 int audit_update_lsm_rules(void)
1814 {
1815 struct audit_krule *r, *n;
1816 int i, err = 0;
1817
1818 /* audit_filter_mutex synchronizes the writers */
1819 mutex_lock(&audit_filter_mutex);
1820
1821 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1822 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
1823 int res = update_lsm_rule(r);
1824 if (!err)
1825 err = res;
1826 }
1827 }
1828 mutex_unlock(&audit_filter_mutex);
1829
1830 return err;
1831 }
1832
1833 /* Update watch data in audit rules based on inotify events. */
audit_handle_ievent(struct inotify_watch * i_watch,u32 wd,u32 mask,u32 cookie,const char * dname,struct inode * inode)1834 void audit_handle_ievent(struct inotify_watch *i_watch, u32 wd, u32 mask,
1835 u32 cookie, const char *dname, struct inode *inode)
1836 {
1837 struct audit_parent *parent;
1838
1839 parent = container_of(i_watch, struct audit_parent, wdata);
1840
1841 if (mask & (IN_CREATE|IN_MOVED_TO) && inode)
1842 audit_update_watch(parent, dname, inode->i_sb->s_dev,
1843 inode->i_ino, 0);
1844 else if (mask & (IN_DELETE|IN_MOVED_FROM))
1845 audit_update_watch(parent, dname, (dev_t)-1, (unsigned long)-1, 1);
1846 /* inotify automatically removes the watch and sends IN_IGNORED */
1847 else if (mask & (IN_DELETE_SELF|IN_UNMOUNT))
1848 audit_remove_parent_watches(parent);
1849 /* inotify does not remove the watch, so remove it manually */
1850 else if(mask & IN_MOVE_SELF) {
1851 audit_remove_parent_watches(parent);
1852 inotify_remove_watch_locked(audit_ih, i_watch);
1853 } else if (mask & IN_IGNORED)
1854 put_inotify_watch(i_watch);
1855 }
1856