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KVM: Reduce stack usage in kvm_arch_vcpu_ioctl()
[linux-2.6.git] / kernel / auditfilter.c
blobb7d354e2b0ef35d618f7a69fee70d301078faa02
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
90 DEFINE_MUTEX(audit_filter_mutex);
91
92 /* Inotify events we care about. */
93 #define AUDIT_IN_WATCH IN_MOVE|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF
94
95 void audit_free_parent(struct inotify_watch *i_watch)
96 {
97 struct audit_parent *parent;
98
99 parent = container_of(i_watch, struct audit_parent, wdata);
100 WARN_ON(!list_empty(&parent->watches));
101 kfree(parent);
102 }
103
104 static inline void audit_get_watch(struct audit_watch *watch)
105 {
106 atomic_inc(&watch->count);
107 }
108
109 static void audit_put_watch(struct audit_watch *watch)
110 {
111 if (atomic_dec_and_test(&watch->count)) {
112 WARN_ON(watch->parent);
113 WARN_ON(!list_empty(&watch->rules));
114 kfree(watch->path);
115 kfree(watch);
116 }
117 }
118
119 static void audit_remove_watch(struct audit_watch *watch)
120 {
121 list_del(&watch->wlist);
122 put_inotify_watch(&watch->parent->wdata);
123 watch->parent = NULL;
124 audit_put_watch(watch); /* match initial get */
125 }
126
127 static inline void audit_free_rule(struct audit_entry *e)
128 {
129 int i;
130
131 /* some rules don't have associated watches */
132 if (e->rule.watch)
133 audit_put_watch(e->rule.watch);
134 if (e->rule.fields)
135 for (i = 0; i < e->rule.field_count; i++) {
136 struct audit_field *f = &e->rule.fields[i];
137 kfree(f->lsm_str);
138 security_audit_rule_free(f->lsm_rule);
139 }
140 kfree(e->rule.fields);
141 kfree(e->rule.filterkey);
142 kfree(e);
143 }
144
145 void audit_free_rule_rcu(struct rcu_head *head)
146 {
147 struct audit_entry *e = container_of(head, struct audit_entry, rcu);
148 audit_free_rule(e);
149 }
150
151 /* Initialize a parent watch entry. */
152 static struct audit_parent *audit_init_parent(struct nameidata *ndp)
153 {
154 struct audit_parent *parent;
155 s32 wd;
156
157 parent = kzalloc(sizeof(*parent), GFP_KERNEL);
158 if (unlikely(!parent))
159 return ERR_PTR(-ENOMEM);
160
161 INIT_LIST_HEAD(&parent->watches);
162 parent->flags = 0;
163
164 inotify_init_watch(&parent->wdata);
165 /* grab a ref so inotify watch hangs around until we take audit_filter_mutex */
166 get_inotify_watch(&parent->wdata);
167 wd = inotify_add_watch(audit_ih, &parent->wdata,
168 ndp->path.dentry->d_inode, AUDIT_IN_WATCH);
169 if (wd < 0) {
170 audit_free_parent(&parent->wdata);
171 return ERR_PTR(wd);
172 }
173
174 return parent;
175 }
176
177 /* Initialize a watch entry. */
178 static struct audit_watch *audit_init_watch(char *path)
179 {
180 struct audit_watch *watch;
181
182 watch = kzalloc(sizeof(*watch), GFP_KERNEL);
183 if (unlikely(!watch))
184 return ERR_PTR(-ENOMEM);
185
186 INIT_LIST_HEAD(&watch->rules);
187 atomic_set(&watch->count, 1);
188 watch->path = path;
189 watch->dev = (dev_t)-1;
190 watch->ino = (unsigned long)-1;
191
192 return watch;
193 }
194
195 /* Initialize an audit filterlist entry. */
196 static inline struct audit_entry *audit_init_entry(u32 field_count)
197 {
198 struct audit_entry *entry;
199 struct audit_field *fields;
200
201 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
202 if (unlikely(!entry))
203 return NULL;
204
205 fields = kzalloc(sizeof(*fields) * field_count, GFP_KERNEL);
206 if (unlikely(!fields)) {
207 kfree(entry);
208 return NULL;
209 }
210 entry->rule.fields = fields;
211
212 return entry;
213 }
214
215 /* Unpack a filter field's string representation from user-space
216 * buffer. */
217 char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
218 {
219 char *str;
220
221 if (!*bufp || (len == 0) || (len > *remain))
222 return ERR_PTR(-EINVAL);
223
224 /* Of the currently implemented string fields, PATH_MAX
225 * defines the longest valid length.
226 */
227 if (len > PATH_MAX)
228 return ERR_PTR(-ENAMETOOLONG);
229
230 str = kmalloc(len + 1, GFP_KERNEL);
231 if (unlikely(!str))
232 return ERR_PTR(-ENOMEM);
233
234 memcpy(str, *bufp, len);
235 str[len] = 0;
236 *bufp += len;
237 *remain -= len;
238
239 return str;
240 }
241
242 /* Translate an inode field to kernel respresentation. */
243 static inline int audit_to_inode(struct audit_krule *krule,
244 struct audit_field *f)
245 {
246 if (krule->listnr != AUDIT_FILTER_EXIT ||
247 krule->watch || krule->inode_f || krule->tree)
248 return -EINVAL;
249
250 krule->inode_f = f;
251 return 0;
252 }
253
254 /* Translate a watch string to kernel respresentation. */
255 static int audit_to_watch(struct audit_krule *krule, char *path, int len,
256 u32 op)
257 {
258 struct audit_watch *watch;
259
260 if (!audit_ih)
261 return -EOPNOTSUPP;
262
263 if (path[0] != '/' || path[len-1] == '/' ||
264 krule->listnr != AUDIT_FILTER_EXIT ||
265 op & ~AUDIT_EQUAL ||
266 krule->inode_f || krule->watch || krule->tree)
267 return -EINVAL;
268
269 watch = audit_init_watch(path);
270 if (IS_ERR(watch))
271 return PTR_ERR(watch);
272
273 audit_get_watch(watch);
274 krule->watch = watch;
275
276 return 0;
277 }
278
279 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
280
281 int __init audit_register_class(int class, unsigned *list)
282 {
283 __u32 *p = kzalloc(AUDIT_BITMASK_SIZE * sizeof(__u32), GFP_KERNEL);
284 if (!p)
285 return -ENOMEM;
286 while (*list != ~0U) {
287 unsigned n = *list++;
288 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
289 kfree(p);
290 return -EINVAL;
291 }
292 p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
293 }
294 if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
295 kfree(p);
296 return -EINVAL;
297 }
298 classes[class] = p;
299 return 0;
300 }
301
302 int audit_match_class(int class, unsigned syscall)
303 {
304 if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
305 return 0;
306 if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
307 return 0;
308 return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
309 }
310
311 #ifdef CONFIG_AUDITSYSCALL
312 static inline int audit_match_class_bits(int class, u32 *mask)
313 {
314 int i;
315
316 if (classes[class]) {
317 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
318 if (mask[i] & classes[class][i])
319 return 0;
320 }
321 return 1;
322 }
323
324 static int audit_match_signal(struct audit_entry *entry)
325 {
326 struct audit_field *arch = entry->rule.arch_f;
327
328 if (!arch) {
329 /* When arch is unspecified, we must check both masks on biarch
330 * as syscall number alone is ambiguous. */
331 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
332 entry->rule.mask) &&
333 audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
334 entry->rule.mask));
335 }
336
337 switch(audit_classify_arch(arch->val)) {
338 case 0: /* native */
339 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
340 entry->rule.mask));
341 case 1: /* 32bit on biarch */
342 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
343 entry->rule.mask));
344 default:
345 return 1;
346 }
347 }
348 #endif
349
350 /* Common user-space to kernel rule translation. */
351 static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule)
352 {
353 unsigned listnr;
354 struct audit_entry *entry;
355 int i, err;
356
357 err = -EINVAL;
358 listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
359 switch(listnr) {
360 default:
361 goto exit_err;
362 case AUDIT_FILTER_USER:
363 case AUDIT_FILTER_TYPE:
364 #ifdef CONFIG_AUDITSYSCALL
365 case AUDIT_FILTER_ENTRY:
366 case AUDIT_FILTER_EXIT:
367 case AUDIT_FILTER_TASK:
368 #endif
369 ;
370 }
371 if (unlikely(rule->action == AUDIT_POSSIBLE)) {
372 printk(KERN_ERR "AUDIT_POSSIBLE is deprecated\n");
373 goto exit_err;
374 }
375 if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
376 goto exit_err;
377 if (rule->field_count > AUDIT_MAX_FIELDS)
378 goto exit_err;
379
380 err = -ENOMEM;
381 entry = audit_init_entry(rule->field_count);
382 if (!entry)
383 goto exit_err;
384
385 entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
386 entry->rule.listnr = listnr;
387 entry->rule.action = rule->action;
388 entry->rule.field_count = rule->field_count;
389
390 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
391 entry->rule.mask[i] = rule->mask[i];
392
393 for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
394 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
395 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
396 __u32 *class;
397
398 if (!(*p & AUDIT_BIT(bit)))
399 continue;
400 *p &= ~AUDIT_BIT(bit);
401 class = classes[i];
402 if (class) {
403 int j;
404 for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
405 entry->rule.mask[j] |= class[j];
406 }
407 }
408
409 return entry;
410
411 exit_err:
412 return ERR_PTR(err);
413 }
414
415 /* Translate struct audit_rule to kernel's rule respresentation.
416 * Exists for backward compatibility with userspace. */
417 static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
418 {
419 struct audit_entry *entry;
420 struct audit_field *ino_f;
421 int err = 0;
422 int i;
423
424 entry = audit_to_entry_common(rule);
425 if (IS_ERR(entry))
426 goto exit_nofree;
427
428 for (i = 0; i < rule->field_count; i++) {
429 struct audit_field *f = &entry->rule.fields[i];
430
431 f->op = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS);
432 f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS);
433 f->val = rule->values[i];
434
435 err = -EINVAL;
436 switch(f->type) {
437 default:
438 goto exit_free;
439 case AUDIT_PID:
440 case AUDIT_UID:
441 case AUDIT_EUID:
442 case AUDIT_SUID:
443 case AUDIT_FSUID:
444 case AUDIT_GID:
445 case AUDIT_EGID:
446 case AUDIT_SGID:
447 case AUDIT_FSGID:
448 case AUDIT_LOGINUID:
449 case AUDIT_PERS:
450 case AUDIT_MSGTYPE:
451 case AUDIT_PPID:
452 case AUDIT_DEVMAJOR:
453 case AUDIT_DEVMINOR:
454 case AUDIT_EXIT:
455 case AUDIT_SUCCESS:
456 /* bit ops are only useful on syscall args */
457 if (f->op == AUDIT_BIT_MASK ||
458 f->op == AUDIT_BIT_TEST) {
459 err = -EINVAL;
460 goto exit_free;
461 }
462 break;
463 case AUDIT_ARG0:
464 case AUDIT_ARG1:
465 case AUDIT_ARG2:
466 case AUDIT_ARG3:
467 break;
468 /* arch is only allowed to be = or != */
469 case AUDIT_ARCH:
470 if ((f->op != AUDIT_NOT_EQUAL) && (f->op != AUDIT_EQUAL)
471 && (f->op != AUDIT_NEGATE) && (f->op)) {
472 err = -EINVAL;
473 goto exit_free;
474 }
475 entry->rule.arch_f = f;
476 break;
477 case AUDIT_PERM:
478 if (f->val & ~15)
479 goto exit_free;
480 break;
481 case AUDIT_FILETYPE:
482 if ((f->val & ~S_IFMT) > S_IFMT)
483 goto exit_free;
484 break;
485 case AUDIT_INODE:
486 err = audit_to_inode(&entry->rule, f);
487 if (err)
488 goto exit_free;
489 break;
490 }
491
492 entry->rule.vers_ops = (f->op & AUDIT_OPERATORS) ? 2 : 1;
493
494 /* Support for legacy operators where
495 * AUDIT_NEGATE bit signifies != and otherwise assumes == */
496 if (f->op & AUDIT_NEGATE)
497 f->op = AUDIT_NOT_EQUAL;
498 else if (!f->op)
499 f->op = AUDIT_EQUAL;
500 else if (f->op == AUDIT_OPERATORS) {
501 err = -EINVAL;
502 goto exit_free;
503 }
504 }
505
506 ino_f = entry->rule.inode_f;
507 if (ino_f) {
508 switch(ino_f->op) {
509 case AUDIT_NOT_EQUAL:
510 entry->rule.inode_f = NULL;
511 case AUDIT_EQUAL:
512 break;
513 default:
514 err = -EINVAL;
515 goto exit_free;
516 }
517 }
518
519 exit_nofree:
520 return entry;
521
522 exit_free:
523 audit_free_rule(entry);
524 return ERR_PTR(err);
525 }
526
527 /* Translate struct audit_rule_data to kernel's rule respresentation. */
528 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
529 size_t datasz)
530 {
531 int err = 0;
532 struct audit_entry *entry;
533 struct audit_field *ino_f;
534 void *bufp;
535 size_t remain = datasz - sizeof(struct audit_rule_data);
536 int i;
537 char *str;
538
539 entry = audit_to_entry_common((struct audit_rule *)data);
540 if (IS_ERR(entry))
541 goto exit_nofree;
542
543 bufp = data->buf;
544 entry->rule.vers_ops = 2;
545 for (i = 0; i < data->field_count; i++) {
546 struct audit_field *f = &entry->rule.fields[i];
547
548 err = -EINVAL;
549 if (!(data->fieldflags[i] & AUDIT_OPERATORS) ||
550 data->fieldflags[i] & ~AUDIT_OPERATORS)
551 goto exit_free;
552
553 f->op = data->fieldflags[i] & AUDIT_OPERATORS;
554 f->type = data->fields[i];
555 f->val = data->values[i];
556 f->lsm_str = NULL;
557 f->lsm_rule = NULL;
558 switch(f->type) {
559 case AUDIT_PID:
560 case AUDIT_UID:
561 case AUDIT_EUID:
562 case AUDIT_SUID:
563 case AUDIT_FSUID:
564 case AUDIT_GID:
565 case AUDIT_EGID:
566 case AUDIT_SGID:
567 case AUDIT_FSGID:
568 case AUDIT_LOGINUID:
569 case AUDIT_PERS:
570 case AUDIT_MSGTYPE:
571 case AUDIT_PPID:
572 case AUDIT_DEVMAJOR:
573 case AUDIT_DEVMINOR:
574 case AUDIT_EXIT:
575 case AUDIT_SUCCESS:
576 case AUDIT_ARG0:
577 case AUDIT_ARG1:
578 case AUDIT_ARG2:
579 case AUDIT_ARG3:
580 break;
581 case AUDIT_ARCH:
582 entry->rule.arch_f = f;
583 break;
584 case AUDIT_SUBJ_USER:
585 case AUDIT_SUBJ_ROLE:
586 case AUDIT_SUBJ_TYPE:
587 case AUDIT_SUBJ_SEN:
588 case AUDIT_SUBJ_CLR:
589 case AUDIT_OBJ_USER:
590 case AUDIT_OBJ_ROLE:
591 case AUDIT_OBJ_TYPE:
592 case AUDIT_OBJ_LEV_LOW:
593 case AUDIT_OBJ_LEV_HIGH:
594 str = audit_unpack_string(&bufp, &remain, f->val);
595 if (IS_ERR(str))
596 goto exit_free;
597 entry->rule.buflen += f->val;
598
599 err = security_audit_rule_init(f->type, f->op, str,
600 (void **)&f->lsm_rule);
601 /* Keep currently invalid fields around in case they
602 * become valid after a policy reload. */
603 if (err == -EINVAL) {
604 printk(KERN_WARNING "audit rule for LSM "
605 "\'%s\' is invalid\n", str);
606 err = 0;
607 }
608 if (err) {
609 kfree(str);
610 goto exit_free;
611 } else
612 f->lsm_str = str;
613 break;
614 case AUDIT_WATCH:
615 str = audit_unpack_string(&bufp, &remain, f->val);
616 if (IS_ERR(str))
617 goto exit_free;
618 entry->rule.buflen += f->val;
619
620 err = audit_to_watch(&entry->rule, str, f->val, f->op);
621 if (err) {
622 kfree(str);
623 goto exit_free;
624 }
625 break;
626 case AUDIT_DIR:
627 str = audit_unpack_string(&bufp, &remain, f->val);
628 if (IS_ERR(str))
629 goto exit_free;
630 entry->rule.buflen += f->val;
631
632 err = audit_make_tree(&entry->rule, str, f->op);
633 kfree(str);
634 if (err)
635 goto exit_free;
636 break;
637 case AUDIT_INODE:
638 err = audit_to_inode(&entry->rule, f);
639 if (err)
640 goto exit_free;
641 break;
642 case AUDIT_FILTERKEY:
643 err = -EINVAL;
644 if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
645 goto exit_free;
646 str = audit_unpack_string(&bufp, &remain, f->val);
647 if (IS_ERR(str))
648 goto exit_free;
649 entry->rule.buflen += f->val;
650 entry->rule.filterkey = str;
651 break;
652 case AUDIT_PERM:
653 if (f->val & ~15)
654 goto exit_free;
655 break;
656 case AUDIT_FILETYPE:
657 if ((f->val & ~S_IFMT) > S_IFMT)
658 goto exit_free;
659 break;
660 default:
661 goto exit_free;
662 }
663 }
664
665 ino_f = entry->rule.inode_f;
666 if (ino_f) {
667 switch(ino_f->op) {
668 case AUDIT_NOT_EQUAL:
669 entry->rule.inode_f = NULL;
670 case AUDIT_EQUAL:
671 break;
672 default:
673 err = -EINVAL;
674 goto exit_free;
675 }
676 }
677
678 exit_nofree:
679 return entry;
680
681 exit_free:
682 audit_free_rule(entry);
683 return ERR_PTR(err);
684 }
685
686 /* Pack a filter field's string representation into data block. */
687 static inline size_t audit_pack_string(void **bufp, const char *str)
688 {
689 size_t len = strlen(str);
690
691 memcpy(*bufp, str, len);
692 *bufp += len;
693
694 return len;
695 }
696
697 /* Translate kernel rule respresentation to struct audit_rule.
698 * Exists for backward compatibility with userspace. */
699 static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
700 {
701 struct audit_rule *rule;
702 int i;
703
704 rule = kzalloc(sizeof(*rule), GFP_KERNEL);
705 if (unlikely(!rule))
706 return NULL;
707
708 rule->flags = krule->flags | krule->listnr;
709 rule->action = krule->action;
710 rule->field_count = krule->field_count;
711 for (i = 0; i < rule->field_count; i++) {
712 rule->values[i] = krule->fields[i].val;
713 rule->fields[i] = krule->fields[i].type;
714
715 if (krule->vers_ops == 1) {
716 if (krule->fields[i].op & AUDIT_NOT_EQUAL)
717 rule->fields[i] |= AUDIT_NEGATE;
718 } else {
719 rule->fields[i] |= krule->fields[i].op;
720 }
721 }
722 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
723
724 return rule;
725 }
726
727 /* Translate kernel rule respresentation to struct audit_rule_data. */
728 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
729 {
730 struct audit_rule_data *data;
731 void *bufp;
732 int i;
733
734 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
735 if (unlikely(!data))
736 return NULL;
737 memset(data, 0, sizeof(*data));
738
739 data->flags = krule->flags | krule->listnr;
740 data->action = krule->action;
741 data->field_count = krule->field_count;
742 bufp = data->buf;
743 for (i = 0; i < data->field_count; i++) {
744 struct audit_field *f = &krule->fields[i];
745
746 data->fields[i] = f->type;
747 data->fieldflags[i] = f->op;
748 switch(f->type) {
749 case AUDIT_SUBJ_USER:
750 case AUDIT_SUBJ_ROLE:
751 case AUDIT_SUBJ_TYPE:
752 case AUDIT_SUBJ_SEN:
753 case AUDIT_SUBJ_CLR:
754 case AUDIT_OBJ_USER:
755 case AUDIT_OBJ_ROLE:
756 case AUDIT_OBJ_TYPE:
757 case AUDIT_OBJ_LEV_LOW:
758 case AUDIT_OBJ_LEV_HIGH:
759 data->buflen += data->values[i] =
760 audit_pack_string(&bufp, f->lsm_str);
761 break;
762 case AUDIT_WATCH:
763 data->buflen += data->values[i] =
764 audit_pack_string(&bufp, krule->watch->path);
765 break;
766 case AUDIT_DIR:
767 data->buflen += data->values[i] =
768 audit_pack_string(&bufp,
769 audit_tree_path(krule->tree));
770 break;
771 case AUDIT_FILTERKEY:
772 data->buflen += data->values[i] =
773 audit_pack_string(&bufp, krule->filterkey);
774 break;
775 default:
776 data->values[i] = f->val;
777 }
778 }
779 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
780
781 return data;
782 }
783
784 /* Compare two rules in kernel format. Considered success if rules
785 * don't match. */
786 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
787 {
788 int i;
789
790 if (a->flags != b->flags ||
791 a->listnr != b->listnr ||
792 a->action != b->action ||
793 a->field_count != b->field_count)
794 return 1;
795
796 for (i = 0; i < a->field_count; i++) {
797 if (a->fields[i].type != b->fields[i].type ||
798 a->fields[i].op != b->fields[i].op)
799 return 1;
800
801 switch(a->fields[i].type) {
802 case AUDIT_SUBJ_USER:
803 case AUDIT_SUBJ_ROLE:
804 case AUDIT_SUBJ_TYPE:
805 case AUDIT_SUBJ_SEN:
806 case AUDIT_SUBJ_CLR:
807 case AUDIT_OBJ_USER:
808 case AUDIT_OBJ_ROLE:
809 case AUDIT_OBJ_TYPE:
810 case AUDIT_OBJ_LEV_LOW:
811 case AUDIT_OBJ_LEV_HIGH:
812 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
813 return 1;
814 break;
815 case AUDIT_WATCH:
816 if (strcmp(a->watch->path, b->watch->path))
817 return 1;
818 break;
819 case AUDIT_DIR:
820 if (strcmp(audit_tree_path(a->tree),
821 audit_tree_path(b->tree)))
822 return 1;
823 break;
824 case AUDIT_FILTERKEY:
825 /* both filterkeys exist based on above type compare */
826 if (strcmp(a->filterkey, b->filterkey))
827 return 1;
828 break;
829 default:
830 if (a->fields[i].val != b->fields[i].val)
831 return 1;
832 }
833 }
834
835 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
836 if (a->mask[i] != b->mask[i])
837 return 1;
838
839 return 0;
840 }
841
842 /* Duplicate the given audit watch. The new watch's rules list is initialized
843 * to an empty list and wlist is undefined. */
844 static struct audit_watch *audit_dupe_watch(struct audit_watch *old)
845 {
846 char *path;
847 struct audit_watch *new;
848
849 path = kstrdup(old->path, GFP_KERNEL);
850 if (unlikely(!path))
851 return ERR_PTR(-ENOMEM);
852
853 new = audit_init_watch(path);
854 if (IS_ERR(new)) {
855 kfree(path);
856 goto out;
857 }
858
859 new->dev = old->dev;
860 new->ino = old->ino;
861 get_inotify_watch(&old->parent->wdata);
862 new->parent = old->parent;
863
864 out:
865 return new;
866 }
867
868 /* Duplicate LSM field information. The lsm_rule is opaque, so must be
869 * re-initialized. */
870 static inline int audit_dupe_lsm_field(struct audit_field *df,
871 struct audit_field *sf)
872 {
873 int ret = 0;
874 char *lsm_str;
875
876 /* our own copy of lsm_str */
877 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
878 if (unlikely(!lsm_str))
879 return -ENOMEM;
880 df->lsm_str = lsm_str;
881
882 /* our own (refreshed) copy of lsm_rule */
883 ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
884 (void **)&df->lsm_rule);
885 /* Keep currently invalid fields around in case they
886 * become valid after a policy reload. */
887 if (ret == -EINVAL) {
888 printk(KERN_WARNING "audit rule for LSM \'%s\' is "
889 "invalid\n", df->lsm_str);
890 ret = 0;
891 }
892
893 return ret;
894 }
895
896 /* Duplicate an audit rule. This will be a deep copy with the exception
897 * of the watch - that pointer is carried over. The LSM specific fields
898 * will be updated in the copy. The point is to be able to replace the old
899 * rule with the new rule in the filterlist, then free the old rule.
900 * The rlist element is undefined; list manipulations are handled apart from
901 * the initial copy. */
902 static struct audit_entry *audit_dupe_rule(struct audit_krule *old,
903 struct audit_watch *watch)
904 {
905 u32 fcount = old->field_count;
906 struct audit_entry *entry;
907 struct audit_krule *new;
908 char *fk;
909 int i, err = 0;
910
911 entry = audit_init_entry(fcount);
912 if (unlikely(!entry))
913 return ERR_PTR(-ENOMEM);
914
915 new = &entry->rule;
916 new->vers_ops = old->vers_ops;
917 new->flags = old->flags;
918 new->listnr = old->listnr;
919 new->action = old->action;
920 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
921 new->mask[i] = old->mask[i];
922 new->buflen = old->buflen;
923 new->inode_f = old->inode_f;
924 new->watch = NULL;
925 new->field_count = old->field_count;
926 /*
927 * note that we are OK with not refcounting here; audit_match_tree()
928 * never dereferences tree and we can't get false positives there
929 * since we'd have to have rule gone from the list *and* removed
930 * before the chunks found by lookup had been allocated, i.e. before
931 * the beginning of list scan.
932 */
933 new->tree = old->tree;
934 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
935
936 /* deep copy this information, updating the lsm_rule fields, because
937 * the originals will all be freed when the old rule is freed. */
938 for (i = 0; i < fcount; i++) {
939 switch (new->fields[i].type) {
940 case AUDIT_SUBJ_USER:
941 case AUDIT_SUBJ_ROLE:
942 case AUDIT_SUBJ_TYPE:
943 case AUDIT_SUBJ_SEN:
944 case AUDIT_SUBJ_CLR:
945 case AUDIT_OBJ_USER:
946 case AUDIT_OBJ_ROLE:
947 case AUDIT_OBJ_TYPE:
948 case AUDIT_OBJ_LEV_LOW:
949 case AUDIT_OBJ_LEV_HIGH:
950 err = audit_dupe_lsm_field(&new->fields[i],
951 &old->fields[i]);
952 break;
953 case AUDIT_FILTERKEY:
954 fk = kstrdup(old->filterkey, GFP_KERNEL);
955 if (unlikely(!fk))
956 err = -ENOMEM;
957 else
958 new->filterkey = fk;
959 }
960 if (err) {
961 audit_free_rule(entry);
962 return ERR_PTR(err);
963 }
964 }
965
966 if (watch) {
967 audit_get_watch(watch);
968 new->watch = watch;
969 }
970
971 return entry;
972 }
973
974 /* Update inode info in audit rules based on filesystem event. */
975 static void audit_update_watch(struct audit_parent *parent,
976 const char *dname, dev_t dev,
977 unsigned long ino, unsigned invalidating)
978 {
979 struct audit_watch *owatch, *nwatch, *nextw;
980 struct audit_krule *r, *nextr;
981 struct audit_entry *oentry, *nentry;
982
983 mutex_lock(&audit_filter_mutex);
984 list_for_each_entry_safe(owatch, nextw, &parent->watches, wlist) {
985 if (audit_compare_dname_path(dname, owatch->path, NULL))
986 continue;
987
988 /* If the update involves invalidating rules, do the inode-based
989 * filtering now, so we don't omit records. */
990 if (invalidating && current->audit_context &&
991 audit_filter_inodes(current, current->audit_context) == AUDIT_RECORD_CONTEXT)
992 audit_set_auditable(current->audit_context);
993
994 nwatch = audit_dupe_watch(owatch);
995 if (IS_ERR(nwatch)) {
996 mutex_unlock(&audit_filter_mutex);
997 audit_panic("error updating watch, skipping");
998 return;
999 }
1000 nwatch->dev = dev;
1001 nwatch->ino = ino;
1002
1003 list_for_each_entry_safe(r, nextr, &owatch->rules, rlist) {
1004
1005 oentry = container_of(r, struct audit_entry, rule);
1006 list_del(&oentry->rule.rlist);
1007 list_del_rcu(&oentry->list);
1008
1009 nentry = audit_dupe_rule(&oentry->rule, nwatch);
1010 if (IS_ERR(nentry))
1011 audit_panic("error updating watch, removing");
1012 else {
1013 int h = audit_hash_ino((u32)ino);
1014 list_add(&nentry->rule.rlist, &nwatch->rules);
1015 list_add_rcu(&nentry->list, &audit_inode_hash[h]);
1016 }
1017
1018 call_rcu(&oentry->rcu, audit_free_rule_rcu);
1019 }
1020
1021 if (audit_enabled) {
1022 struct audit_buffer *ab;
1023 ab = audit_log_start(NULL, GFP_KERNEL,
1024 AUDIT_CONFIG_CHANGE);
1025 audit_log_format(ab, "auid=%u ses=%u",
1026 audit_get_loginuid(current),
1027 audit_get_sessionid(current));
1028 audit_log_format(ab,
1029 " op=updated rules specifying path=");
1030 audit_log_untrustedstring(ab, owatch->path);
1031 audit_log_format(ab, " with dev=%u ino=%lu\n",
1032 dev, ino);
1033 audit_log_format(ab, " list=%d res=1", r->listnr);
1034 audit_log_end(ab);
1035 }
1036 audit_remove_watch(owatch);
1037 goto add_watch_to_parent; /* event applies to a single watch */
1038 }
1039 mutex_unlock(&audit_filter_mutex);
1040 return;
1041
1042 add_watch_to_parent:
1043 list_add(&nwatch->wlist, &parent->watches);
1044 mutex_unlock(&audit_filter_mutex);
1045 return;
1046 }
1047
1048 /* Remove all watches & rules associated with a parent that is going away. */
1049 static void audit_remove_parent_watches(struct audit_parent *parent)
1050 {
1051 struct audit_watch *w, *nextw;
1052 struct audit_krule *r, *nextr;
1053 struct audit_entry *e;
1054
1055 mutex_lock(&audit_filter_mutex);
1056 parent->flags |= AUDIT_PARENT_INVALID;
1057 list_for_each_entry_safe(w, nextw, &parent->watches, wlist) {
1058 list_for_each_entry_safe(r, nextr, &w->rules, rlist) {
1059 e = container_of(r, struct audit_entry, rule);
1060 if (audit_enabled) {
1061 struct audit_buffer *ab;
1062 ab = audit_log_start(NULL, GFP_KERNEL,
1063 AUDIT_CONFIG_CHANGE);
1064 audit_log_format(ab, "auid=%u ses=%u",
1065 audit_get_loginuid(current),
1066 audit_get_sessionid(current));
1067 audit_log_format(ab, " op=remove rule path=");
1068 audit_log_untrustedstring(ab, w->path);
1069 if (r->filterkey) {
1070 audit_log_format(ab, " key=");
1071 audit_log_untrustedstring(ab,
1072 r->filterkey);
1073 } else
1074 audit_log_format(ab, " key=(null)");
1075 audit_log_format(ab, " list=%d res=1",
1076 r->listnr);
1077 audit_log_end(ab);
1078 }
1079 list_del(&r->rlist);
1080 list_del_rcu(&e->list);
1081 call_rcu(&e->rcu, audit_free_rule_rcu);
1082 }
1083 audit_remove_watch(w);
1084 }
1085 mutex_unlock(&audit_filter_mutex);
1086 }
1087
1088 /* Unregister inotify watches for parents on in_list.
1089 * Generates an IN_IGNORED event. */
1090 static void audit_inotify_unregister(struct list_head *in_list)
1091 {
1092 struct audit_parent *p, *n;
1093
1094 list_for_each_entry_safe(p, n, in_list, ilist) {
1095 list_del(&p->ilist);
1096 inotify_rm_watch(audit_ih, &p->wdata);
1097 /* the put matching the get in audit_do_del_rule() */
1098 put_inotify_watch(&p->wdata);
1099 }
1100 }
1101
1102 /* Find an existing audit rule.
1103 * Caller must hold audit_filter_mutex to prevent stale rule data. */
1104 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
1105 struct list_head *list)
1106 {
1107 struct audit_entry *e, *found = NULL;
1108 int h;
1109
1110 if (entry->rule.watch) {
1111 /* we don't know the inode number, so must walk entire hash */
1112 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
1113 list = &audit_inode_hash[h];
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 goto out;
1121 }
1122
1123 list_for_each_entry(e, list, list)
1124 if (!audit_compare_rule(&entry->rule, &e->rule)) {
1125 found = e;
1126 goto out;
1127 }
1128
1129 out:
1130 return found;
1131 }
1132
1133 /* Get path information necessary for adding watches. */
1134 static int audit_get_nd(char *path, struct nameidata **ndp,
1135 struct nameidata **ndw)
1136 {
1137 struct nameidata *ndparent, *ndwatch;
1138 int err;
1139
1140 ndparent = kmalloc(sizeof(*ndparent), GFP_KERNEL);
1141 if (unlikely(!ndparent))
1142 return -ENOMEM;
1143
1144 ndwatch = kmalloc(sizeof(*ndwatch), GFP_KERNEL);
1145 if (unlikely(!ndwatch)) {
1146 kfree(ndparent);
1147 return -ENOMEM;
1148 }
1149
1150 err = path_lookup(path, LOOKUP_PARENT, ndparent);
1151 if (err) {
1152 kfree(ndparent);
1153 kfree(ndwatch);
1154 return err;
1155 }
1156
1157 err = path_lookup(path, 0, ndwatch);
1158 if (err) {
1159 kfree(ndwatch);
1160 ndwatch = NULL;
1161 }
1162
1163 *ndp = ndparent;
1164 *ndw = ndwatch;
1165
1166 return 0;
1167 }
1168
1169 /* Release resources used for watch path information. */
1170 static void audit_put_nd(struct nameidata *ndp, struct nameidata *ndw)
1171 {
1172 if (ndp) {
1173 path_put(&ndp->path);
1174 kfree(ndp);
1175 }
1176 if (ndw) {
1177 path_put(&ndw->path);
1178 kfree(ndw);
1179 }
1180 }
1181
1182 /* Associate the given rule with an existing parent inotify_watch.
1183 * Caller must hold audit_filter_mutex. */
1184 static void audit_add_to_parent(struct audit_krule *krule,
1185 struct audit_parent *parent)
1186 {
1187 struct audit_watch *w, *watch = krule->watch;
1188 int watch_found = 0;
1189
1190 list_for_each_entry(w, &parent->watches, wlist) {
1191 if (strcmp(watch->path, w->path))
1192 continue;
1193
1194 watch_found = 1;
1195
1196 /* put krule's and initial refs to temporary watch */
1197 audit_put_watch(watch);
1198 audit_put_watch(watch);
1199
1200 audit_get_watch(w);
1201 krule->watch = watch = w;
1202 break;
1203 }
1204
1205 if (!watch_found) {
1206 get_inotify_watch(&parent->wdata);
1207 watch->parent = parent;
1208
1209 list_add(&watch->wlist, &parent->watches);
1210 }
1211 list_add(&krule->rlist, &watch->rules);
1212 }
1213
1214 /* Find a matching watch entry, or add this one.
1215 * Caller must hold audit_filter_mutex. */
1216 static int audit_add_watch(struct audit_krule *krule, struct nameidata *ndp,
1217 struct nameidata *ndw)
1218 {
1219 struct audit_watch *watch = krule->watch;
1220 struct inotify_watch *i_watch;
1221 struct audit_parent *parent;
1222 int ret = 0;
1223
1224 /* update watch filter fields */
1225 if (ndw) {
1226 watch->dev = ndw->path.dentry->d_inode->i_sb->s_dev;
1227 watch->ino = ndw->path.dentry->d_inode->i_ino;
1228 }
1229
1230 /* The audit_filter_mutex must not be held during inotify calls because
1231 * we hold it during inotify event callback processing. If an existing
1232 * inotify watch is found, inotify_find_watch() grabs a reference before
1233 * returning.
1234 */
1235 mutex_unlock(&audit_filter_mutex);
1236
1237 if (inotify_find_watch(audit_ih, ndp->path.dentry->d_inode,
1238 &i_watch) < 0) {
1239 parent = audit_init_parent(ndp);
1240 if (IS_ERR(parent)) {
1241 /* caller expects mutex locked */
1242 mutex_lock(&audit_filter_mutex);
1243 return PTR_ERR(parent);
1244 }
1245 } else
1246 parent = container_of(i_watch, struct audit_parent, wdata);
1247
1248 mutex_lock(&audit_filter_mutex);
1249
1250 /* parent was moved before we took audit_filter_mutex */
1251 if (parent->flags & AUDIT_PARENT_INVALID)
1252 ret = -ENOENT;
1253 else
1254 audit_add_to_parent(krule, parent);
1255
1256 /* match get in audit_init_parent or inotify_find_watch */
1257 put_inotify_watch(&parent->wdata);
1258 return ret;
1259 }
1260
1261 /* Add rule to given filterlist if not a duplicate. */
1262 static inline int audit_add_rule(struct audit_entry *entry,
1263 struct list_head *list)
1264 {
1265 struct audit_entry *e;
1266 struct audit_field *inode_f = entry->rule.inode_f;
1267 struct audit_watch *watch = entry->rule.watch;
1268 struct audit_tree *tree = entry->rule.tree;
1269 struct nameidata *ndp = NULL, *ndw = NULL;
1270 int h, err;
1271 #ifdef CONFIG_AUDITSYSCALL
1272 int dont_count = 0;
1273
1274 /* If either of these, don't count towards total */
1275 if (entry->rule.listnr == AUDIT_FILTER_USER ||
1276 entry->rule.listnr == AUDIT_FILTER_TYPE)
1277 dont_count = 1;
1278 #endif
1279
1280 if (inode_f) {
1281 h = audit_hash_ino(inode_f->val);
1282 list = &audit_inode_hash[h];
1283 }
1284
1285 mutex_lock(&audit_filter_mutex);
1286 e = audit_find_rule(entry, list);
1287 mutex_unlock(&audit_filter_mutex);
1288 if (e) {
1289 err = -EEXIST;
1290 /* normally audit_add_tree_rule() will free it on failure */
1291 if (tree)
1292 audit_put_tree(tree);
1293 goto error;
1294 }
1295
1296 /* Avoid calling path_lookup under audit_filter_mutex. */
1297 if (watch) {
1298 err = audit_get_nd(watch->path, &ndp, &ndw);
1299 if (err)
1300 goto error;
1301 }
1302
1303 mutex_lock(&audit_filter_mutex);
1304 if (watch) {
1305 /* audit_filter_mutex is dropped and re-taken during this call */
1306 err = audit_add_watch(&entry->rule, ndp, ndw);
1307 if (err) {
1308 mutex_unlock(&audit_filter_mutex);
1309 goto error;
1310 }
1311 h = audit_hash_ino((u32)watch->ino);
1312 list = &audit_inode_hash[h];
1313 }
1314 if (tree) {
1315 err = audit_add_tree_rule(&entry->rule);
1316 if (err) {
1317 mutex_unlock(&audit_filter_mutex);
1318 goto error;
1319 }
1320 }
1321
1322 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
1323 list_add_rcu(&entry->list, list);
1324 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
1325 } else {
1326 list_add_tail_rcu(&entry->list, list);
1327 }
1328 #ifdef CONFIG_AUDITSYSCALL
1329 if (!dont_count)
1330 audit_n_rules++;
1331
1332 if (!audit_match_signal(entry))
1333 audit_signals++;
1334 #endif
1335 mutex_unlock(&audit_filter_mutex);
1336
1337 audit_put_nd(ndp, ndw); /* NULL args OK */
1338 return 0;
1339
1340 error:
1341 audit_put_nd(ndp, ndw); /* NULL args OK */
1342 if (watch)
1343 audit_put_watch(watch); /* tmp watch, matches initial get */
1344 return err;
1345 }
1346
1347 /* Remove an existing rule from filterlist. */
1348 static inline int audit_del_rule(struct audit_entry *entry,
1349 struct list_head *list)
1350 {
1351 struct audit_entry *e;
1352 struct audit_field *inode_f = entry->rule.inode_f;
1353 struct audit_watch *watch, *tmp_watch = entry->rule.watch;
1354 struct audit_tree *tree = entry->rule.tree;
1355 LIST_HEAD(inotify_list);
1356 int h, ret = 0;
1357 #ifdef CONFIG_AUDITSYSCALL
1358 int dont_count = 0;
1359
1360 /* If either of these, don't count towards total */
1361 if (entry->rule.listnr == AUDIT_FILTER_USER ||
1362 entry->rule.listnr == AUDIT_FILTER_TYPE)
1363 dont_count = 1;
1364 #endif
1365
1366 if (inode_f) {
1367 h = audit_hash_ino(inode_f->val);
1368 list = &audit_inode_hash[h];
1369 }
1370
1371 mutex_lock(&audit_filter_mutex);
1372 e = audit_find_rule(entry, list);
1373 if (!e) {
1374 mutex_unlock(&audit_filter_mutex);
1375 ret = -ENOENT;
1376 goto out;
1377 }
1378
1379 watch = e->rule.watch;
1380 if (watch) {
1381 struct audit_parent *parent = watch->parent;
1382
1383 list_del(&e->rule.rlist);
1384
1385 if (list_empty(&watch->rules)) {
1386 audit_remove_watch(watch);
1387
1388 if (list_empty(&parent->watches)) {
1389 /* Put parent on the inotify un-registration
1390 * list. Grab a reference before releasing
1391 * audit_filter_mutex, to be released in
1392 * audit_inotify_unregister(). */
1393 list_add(&parent->ilist, &inotify_list);
1394 get_inotify_watch(&parent->wdata);
1395 }
1396 }
1397 }
1398
1399 if (e->rule.tree)
1400 audit_remove_tree_rule(&e->rule);
1401
1402 list_del_rcu(&e->list);
1403 call_rcu(&e->rcu, audit_free_rule_rcu);
1404
1405 #ifdef CONFIG_AUDITSYSCALL
1406 if (!dont_count)
1407 audit_n_rules--;
1408
1409 if (!audit_match_signal(entry))
1410 audit_signals--;
1411 #endif
1412 mutex_unlock(&audit_filter_mutex);
1413
1414 if (!list_empty(&inotify_list))
1415 audit_inotify_unregister(&inotify_list);
1416
1417 out:
1418 if (tmp_watch)
1419 audit_put_watch(tmp_watch); /* match initial get */
1420 if (tree)
1421 audit_put_tree(tree); /* that's the temporary one */
1422
1423 return ret;
1424 }
1425
1426 /* List rules using struct audit_rule. Exists for backward
1427 * compatibility with userspace. */
1428 static void audit_list(int pid, int seq, struct sk_buff_head *q)
1429 {
1430 struct sk_buff *skb;
1431 struct audit_entry *entry;
1432 int i;
1433
1434 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1435 * iterator to sync with list writers. */
1436 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1437 list_for_each_entry(entry, &audit_filter_list[i], list) {
1438 struct audit_rule *rule;
1439
1440 rule = audit_krule_to_rule(&entry->rule);
1441 if (unlikely(!rule))
1442 break;
1443 skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1444 rule, sizeof(*rule));
1445 if (skb)
1446 skb_queue_tail(q, skb);
1447 kfree(rule);
1448 }
1449 }
1450 for (i = 0; i < AUDIT_INODE_BUCKETS; i++) {
1451 list_for_each_entry(entry, &audit_inode_hash[i], list) {
1452 struct audit_rule *rule;
1453
1454 rule = audit_krule_to_rule(&entry->rule);
1455 if (unlikely(!rule))
1456 break;
1457 skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1458 rule, sizeof(*rule));
1459 if (skb)
1460 skb_queue_tail(q, skb);
1461 kfree(rule);
1462 }
1463 }
1464 skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
1465 if (skb)
1466 skb_queue_tail(q, skb);
1467 }
1468
1469 /* List rules using struct audit_rule_data. */
1470 static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
1471 {
1472 struct sk_buff *skb;
1473 struct audit_entry *e;
1474 int i;
1475
1476 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1477 * iterator to sync with list writers. */
1478 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1479 list_for_each_entry(e, &audit_filter_list[i], list) {
1480 struct audit_rule_data *data;
1481
1482 data = audit_krule_to_data(&e->rule);
1483 if (unlikely(!data))
1484 break;
1485 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1486 data, sizeof(*data) + data->buflen);
1487 if (skb)
1488 skb_queue_tail(q, skb);
1489 kfree(data);
1490 }
1491 }
1492 for (i=0; i< AUDIT_INODE_BUCKETS; i++) {
1493 list_for_each_entry(e, &audit_inode_hash[i], list) {
1494 struct audit_rule_data *data;
1495
1496 data = audit_krule_to_data(&e->rule);
1497 if (unlikely(!data))
1498 break;
1499 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1500 data, sizeof(*data) + data->buflen);
1501 if (skb)
1502 skb_queue_tail(q, skb);
1503 kfree(data);
1504 }
1505 }
1506 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1507 if (skb)
1508 skb_queue_tail(q, skb);
1509 }
1510
1511 /* Log rule additions and removals */
1512 static void audit_log_rule_change(uid_t loginuid, u32 sessionid, u32 sid,
1513 char *action, struct audit_krule *rule,
1514 int res)
1515 {
1516 struct audit_buffer *ab;
1517
1518 if (!audit_enabled)
1519 return;
1520
1521 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1522 if (!ab)
1523 return;
1524 audit_log_format(ab, "auid=%u ses=%u", loginuid, sessionid);
1525 if (sid) {
1526 char *ctx = NULL;
1527 u32 len;
1528 if (security_secid_to_secctx(sid, &ctx, &len))
1529 audit_log_format(ab, " ssid=%u", sid);
1530 else {
1531 audit_log_format(ab, " subj=%s", ctx);
1532 security_release_secctx(ctx, len);
1533 }
1534 }
1535 audit_log_format(ab, " op=%s rule key=", action);
1536 if (rule->filterkey)
1537 audit_log_untrustedstring(ab, rule->filterkey);
1538 else
1539 audit_log_format(ab, "(null)");
1540 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1541 audit_log_end(ab);
1542 }
1543
1544 /**
1545 * audit_receive_filter - apply all rules to the specified message type
1546 * @type: audit message type
1547 * @pid: target pid for netlink audit messages
1548 * @uid: target uid for netlink audit messages
1549 * @seq: netlink audit message sequence (serial) number
1550 * @data: payload data
1551 * @datasz: size of payload data
1552 * @loginuid: loginuid of sender
1553 * @sessionid: sessionid for netlink audit message
1554 * @sid: SE Linux Security ID of sender
1555 */
1556 int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
1557 size_t datasz, uid_t loginuid, u32 sessionid, u32 sid)
1558 {
1559 struct task_struct *tsk;
1560 struct audit_netlink_list *dest;
1561 int err = 0;
1562 struct audit_entry *entry;
1563
1564 switch (type) {
1565 case AUDIT_LIST:
1566 case AUDIT_LIST_RULES:
1567 /* We can't just spew out the rules here because we might fill
1568 * the available socket buffer space and deadlock waiting for
1569 * auditctl to read from it... which isn't ever going to
1570 * happen if we're actually running in the context of auditctl
1571 * trying to _send_ the stuff */
1572
1573 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1574 if (!dest)
1575 return -ENOMEM;
1576 dest->pid = pid;
1577 skb_queue_head_init(&dest->q);
1578
1579 mutex_lock(&audit_filter_mutex);
1580 if (type == AUDIT_LIST)
1581 audit_list(pid, seq, &dest->q);
1582 else
1583 audit_list_rules(pid, seq, &dest->q);
1584 mutex_unlock(&audit_filter_mutex);
1585
1586 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1587 if (IS_ERR(tsk)) {
1588 skb_queue_purge(&dest->q);
1589 kfree(dest);
1590 err = PTR_ERR(tsk);
1591 }
1592 break;
1593 case AUDIT_ADD:
1594 case AUDIT_ADD_RULE:
1595 if (type == AUDIT_ADD)
1596 entry = audit_rule_to_entry(data);
1597 else
1598 entry = audit_data_to_entry(data, datasz);
1599 if (IS_ERR(entry))
1600 return PTR_ERR(entry);
1601
1602 err = audit_add_rule(entry,
1603 &audit_filter_list[entry->rule.listnr]);
1604 audit_log_rule_change(loginuid, sessionid, sid, "add",
1605 &entry->rule, !err);
1606
1607 if (err)
1608 audit_free_rule(entry);
1609 break;
1610 case AUDIT_DEL:
1611 case AUDIT_DEL_RULE:
1612 if (type == AUDIT_DEL)
1613 entry = audit_rule_to_entry(data);
1614 else
1615 entry = audit_data_to_entry(data, datasz);
1616 if (IS_ERR(entry))
1617 return PTR_ERR(entry);
1618
1619 err = audit_del_rule(entry,
1620 &audit_filter_list[entry->rule.listnr]);
1621 audit_log_rule_change(loginuid, sessionid, sid, "remove",
1622 &entry->rule, !err);
1623
1624 audit_free_rule(entry);
1625 break;
1626 default:
1627 return -EINVAL;
1628 }
1629
1630 return err;
1631 }
1632
1633 int audit_comparator(const u32 left, const u32 op, const u32 right)
1634 {
1635 switch (op) {
1636 case AUDIT_EQUAL:
1637 return (left == right);
1638 case AUDIT_NOT_EQUAL:
1639 return (left != right);
1640 case AUDIT_LESS_THAN:
1641 return (left < right);
1642 case AUDIT_LESS_THAN_OR_EQUAL:
1643 return (left <= right);
1644 case AUDIT_GREATER_THAN:
1645 return (left > right);
1646 case AUDIT_GREATER_THAN_OR_EQUAL:
1647 return (left >= right);
1648 case AUDIT_BIT_MASK:
1649 return (left & right);
1650 case AUDIT_BIT_TEST:
1651 return ((left & right) == right);
1652 }
1653 BUG();
1654 return 0;
1655 }
1656
1657 /* Compare given dentry name with last component in given path,
1658 * return of 0 indicates a match. */
1659 int audit_compare_dname_path(const char *dname, const char *path,
1660 int *dirlen)
1661 {
1662 int dlen, plen;
1663 const char *p;
1664
1665 if (!dname || !path)
1666 return 1;
1667
1668 dlen = strlen(dname);
1669 plen = strlen(path);
1670 if (plen < dlen)
1671 return 1;
1672
1673 /* disregard trailing slashes */
1674 p = path + plen - 1;
1675 while ((*p == '/') && (p > path))
1676 p--;
1677
1678 /* find last path component */
1679 p = p - dlen + 1;
1680 if (p < path)
1681 return 1;
1682 else if (p > path) {
1683 if (*--p != '/')
1684 return 1;
1685 else
1686 p++;
1687 }
1688
1689 /* return length of path's directory component */
1690 if (dirlen)
1691 *dirlen = p - path;
1692 return strncmp(p, dname, dlen);
1693 }
1694
1695 static int audit_filter_user_rules(struct netlink_skb_parms *cb,
1696 struct audit_krule *rule,
1697 enum audit_state *state)
1698 {
1699 int i;
1700
1701 for (i = 0; i < rule->field_count; i++) {
1702 struct audit_field *f = &rule->fields[i];
1703 int result = 0;
1704
1705 switch (f->type) {
1706 case AUDIT_PID:
1707 result = audit_comparator(cb->creds.pid, f->op, f->val);
1708 break;
1709 case AUDIT_UID:
1710 result = audit_comparator(cb->creds.uid, f->op, f->val);
1711 break;
1712 case AUDIT_GID:
1713 result = audit_comparator(cb->creds.gid, f->op, f->val);
1714 break;
1715 case AUDIT_LOGINUID:
1716 result = audit_comparator(cb->loginuid, f->op, f->val);
1717 break;
1718 }
1719
1720 if (!result)
1721 return 0;
1722 }
1723 switch (rule->action) {
1724 case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
1725 case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
1726 }
1727 return 1;
1728 }
1729
1730 int audit_filter_user(struct netlink_skb_parms *cb)
1731 {
1732 enum audit_state state = AUDIT_DISABLED;
1733 struct audit_entry *e;
1734 int ret = 1;
1735
1736 rcu_read_lock();
1737 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1738 if (audit_filter_user_rules(cb, &e->rule, &state)) {
1739 if (state == AUDIT_DISABLED)
1740 ret = 0;
1741 break;
1742 }
1743 }
1744 rcu_read_unlock();
1745
1746 return ret; /* Audit by default */
1747 }
1748
1749 int audit_filter_type(int type)
1750 {
1751 struct audit_entry *e;
1752 int result = 0;
1753
1754 rcu_read_lock();
1755 if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1756 goto unlock_and_return;
1757
1758 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1759 list) {
1760 int i;
1761 for (i = 0; i < e->rule.field_count; i++) {
1762 struct audit_field *f = &e->rule.fields[i];
1763 if (f->type == AUDIT_MSGTYPE) {
1764 result = audit_comparator(type, f->op, f->val);
1765 if (!result)
1766 break;
1767 }
1768 }
1769 if (result)
1770 goto unlock_and_return;
1771 }
1772 unlock_and_return:
1773 rcu_read_unlock();
1774 return result;
1775 }
1776
1777 /* This function will re-initialize the lsm_rule field of all applicable rules.
1778 * It will traverse the filter lists serarching for rules that contain LSM
1779 * specific filter fields. When such a rule is found, it is copied, the
1780 * LSM field is re-initialized, and the old rule is replaced with the
1781 * updated rule. */
1782 int audit_update_lsm_rules(void)
1783 {
1784 struct audit_entry *entry, *n, *nentry;
1785 struct audit_watch *watch;
1786 struct audit_tree *tree;
1787 int i, err = 0;
1788
1789 /* audit_filter_mutex synchronizes the writers */
1790 mutex_lock(&audit_filter_mutex);
1791
1792 for (i = 0; i < AUDIT_NR_FILTERS; i++) {
1793 list_for_each_entry_safe(entry, n, &audit_filter_list[i], list) {
1794 if (!security_audit_rule_known(&entry->rule))
1795 continue;
1796
1797 watch = entry->rule.watch;
1798 tree = entry->rule.tree;
1799 nentry = audit_dupe_rule(&entry->rule, watch);
1800 if (IS_ERR(nentry)) {
1801 /* save the first error encountered for the
1802 * return value */
1803 if (!err)
1804 err = PTR_ERR(nentry);
1805 audit_panic("error updating LSM filters");
1806 if (watch)
1807 list_del(&entry->rule.rlist);
1808 list_del_rcu(&entry->list);
1809 } else {
1810 if (watch) {
1811 list_add(&nentry->rule.rlist,
1812 &watch->rules);
1813 list_del(&entry->rule.rlist);
1814 } else if (tree)
1815 list_replace_init(&entry->rule.rlist,
1816 &nentry->rule.rlist);
1817 list_replace_rcu(&entry->list, &nentry->list);
1818 }
1819 call_rcu(&entry->rcu, audit_free_rule_rcu);
1820 }
1821 }
1822
1823 mutex_unlock(&audit_filter_mutex);
1824
1825 return err;
1826 }
1827
1828 /* Update watch data in audit rules based on inotify events. */
1829 void audit_handle_ievent(struct inotify_watch *i_watch, u32 wd, u32 mask,
1830 u32 cookie, const char *dname, struct inode *inode)
1831 {
1832 struct audit_parent *parent;
1833
1834 parent = container_of(i_watch, struct audit_parent, wdata);
1835
1836 if (mask & (IN_CREATE|IN_MOVED_TO) && inode)
1837 audit_update_watch(parent, dname, inode->i_sb->s_dev,
1838 inode->i_ino, 0);
1839 else if (mask & (IN_DELETE|IN_MOVED_FROM))
1840 audit_update_watch(parent, dname, (dev_t)-1, (unsigned long)-1, 1);
1841 /* inotify automatically removes the watch and sends IN_IGNORED */
1842 else if (mask & (IN_DELETE_SELF|IN_UNMOUNT))
1843 audit_remove_parent_watches(parent);
1844 /* inotify does not remove the watch, so remove it manually */
1845 else if(mask & IN_MOVE_SELF) {
1846 audit_remove_parent_watches(parent);
1847 inotify_remove_watch_locked(audit_ih, i_watch);
1848 } else if (mask & IN_IGNORED)
1849 put_inotify_watch(i_watch);
1850 }
Linus' kernel tree