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Use access mode instead of open flags to determine needed permissions
[pv_ops_mirror.git] / kernel / auditfilter.c
blob5d96f2cc7be8137164f8881d830ad013f39da949
1 /* auditfilter.c -- filtering of audit events
2 *
3 * Copyright 2003-2004 Red Hat, Inc.
4 * Copyright 2005 Hewlett-Packard Development Company, L.P.
5 * Copyright 2005 IBM Corporation
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21
22 #include <linux/kernel.h>
23 #include <linux/audit.h>
24 #include <linux/kthread.h>
25 #include <linux/mutex.h>
26 #include <linux/fs.h>
27 #include <linux/namei.h>
28 #include <linux/netlink.h>
29 #include <linux/sched.h>
30 #include <linux/inotify.h>
31 #include <linux/selinux.h>
32 #include "audit.h"
33
34 /*
35 * Locking model:
36 *
37 * audit_filter_mutex:
38 * Synchronizes writes and blocking reads of audit's filterlist
39 * data. Rcu is used to traverse the filterlist and access
40 * contents of structs audit_entry, audit_watch and opaque
41 * selinux rules during filtering. If modified, these structures
42 * must be copied and replace their counterparts in the filterlist.
43 * An audit_parent struct is not accessed during filtering, so may
44 * be written directly provided audit_filter_mutex is held.
45 */
46
47 /*
48 * Reference counting:
49 *
50 * audit_parent: lifetime is from audit_init_parent() to receipt of an IN_IGNORED
51 * event. Each audit_watch holds a reference to its associated parent.
52 *
53 * audit_watch: if added to lists, lifetime is from audit_init_watch() to
54 * audit_remove_watch(). Additionally, an audit_watch may exist
55 * temporarily to assist in searching existing filter data. Each
56 * audit_krule holds a reference to its associated watch.
57 */
58
59 struct audit_parent {
60 struct list_head ilist; /* entry in inotify registration list */
61 struct list_head watches; /* associated watches */
62 struct inotify_watch wdata; /* inotify watch data */
63 unsigned flags; /* status flags */
64 };
65
66 /*
67 * audit_parent status flags:
68 *
69 * AUDIT_PARENT_INVALID - set anytime rules/watches are auto-removed due to
70 * a filesystem event to ensure we're adding audit watches to a valid parent.
71 * Technically not needed for IN_DELETE_SELF or IN_UNMOUNT events, as we cannot
72 * receive them while we have nameidata, but must be used for IN_MOVE_SELF which
73 * we can receive while holding nameidata.
74 */
75 #define AUDIT_PARENT_INVALID 0x001
76
77 /* Audit filter lists, defined in <linux/audit.h> */
78 struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
79 LIST_HEAD_INIT(audit_filter_list[0]),
80 LIST_HEAD_INIT(audit_filter_list[1]),
81 LIST_HEAD_INIT(audit_filter_list[2]),
82 LIST_HEAD_INIT(audit_filter_list[3]),
83 LIST_HEAD_INIT(audit_filter_list[4]),
84 LIST_HEAD_INIT(audit_filter_list[5]),
85 #if AUDIT_NR_FILTERS != 6
86 #error Fix audit_filter_list initialiser
87 #endif
88 };
89
90 DEFINE_MUTEX(audit_filter_mutex);
91
92 /* Inotify handle */
93 extern struct inotify_handle *audit_ih;
94
95 /* Inotify events we care about. */
96 #define AUDIT_IN_WATCH IN_MOVE|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF
97
98 void audit_free_parent(struct inotify_watch *i_watch)
99 {
100 struct audit_parent *parent;
101
102 parent = container_of(i_watch, struct audit_parent, wdata);
103 WARN_ON(!list_empty(&parent->watches));
104 kfree(parent);
105 }
106
107 static inline void audit_get_watch(struct audit_watch *watch)
108 {
109 atomic_inc(&watch->count);
110 }
111
112 static void audit_put_watch(struct audit_watch *watch)
113 {
114 if (atomic_dec_and_test(&watch->count)) {
115 WARN_ON(watch->parent);
116 WARN_ON(!list_empty(&watch->rules));
117 kfree(watch->path);
118 kfree(watch);
119 }
120 }
121
122 static void audit_remove_watch(struct audit_watch *watch)
123 {
124 list_del(&watch->wlist);
125 put_inotify_watch(&watch->parent->wdata);
126 watch->parent = NULL;
127 audit_put_watch(watch); /* match initial get */
128 }
129
130 static inline void audit_free_rule(struct audit_entry *e)
131 {
132 int i;
133
134 /* some rules don't have associated watches */
135 if (e->rule.watch)
136 audit_put_watch(e->rule.watch);
137 if (e->rule.fields)
138 for (i = 0; i < e->rule.field_count; i++) {
139 struct audit_field *f = &e->rule.fields[i];
140 kfree(f->se_str);
141 selinux_audit_rule_free(f->se_rule);
142 }
143 kfree(e->rule.fields);
144 kfree(e->rule.filterkey);
145 kfree(e);
146 }
147
148 void audit_free_rule_rcu(struct rcu_head *head)
149 {
150 struct audit_entry *e = container_of(head, struct audit_entry, rcu);
151 audit_free_rule(e);
152 }
153
154 /* Initialize a parent watch entry. */
155 static struct audit_parent *audit_init_parent(struct nameidata *ndp)
156 {
157 struct audit_parent *parent;
158 s32 wd;
159
160 parent = kzalloc(sizeof(*parent), GFP_KERNEL);
161 if (unlikely(!parent))
162 return ERR_PTR(-ENOMEM);
163
164 INIT_LIST_HEAD(&parent->watches);
165 parent->flags = 0;
166
167 inotify_init_watch(&parent->wdata);
168 /* grab a ref so inotify watch hangs around until we take audit_filter_mutex */
169 get_inotify_watch(&parent->wdata);
170 wd = inotify_add_watch(audit_ih, &parent->wdata, ndp->dentry->d_inode,
171 AUDIT_IN_WATCH);
172 if (wd < 0) {
173 audit_free_parent(&parent->wdata);
174 return ERR_PTR(wd);
175 }
176
177 return parent;
178 }
179
180 /* Initialize a watch entry. */
181 static struct audit_watch *audit_init_watch(char *path)
182 {
183 struct audit_watch *watch;
184
185 watch = kzalloc(sizeof(*watch), GFP_KERNEL);
186 if (unlikely(!watch))
187 return ERR_PTR(-ENOMEM);
188
189 INIT_LIST_HEAD(&watch->rules);
190 atomic_set(&watch->count, 1);
191 watch->path = path;
192 watch->dev = (dev_t)-1;
193 watch->ino = (unsigned long)-1;
194
195 return watch;
196 }
197
198 /* Initialize an audit filterlist entry. */
199 static inline struct audit_entry *audit_init_entry(u32 field_count)
200 {
201 struct audit_entry *entry;
202 struct audit_field *fields;
203
204 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
205 if (unlikely(!entry))
206 return NULL;
207
208 fields = kzalloc(sizeof(*fields) * field_count, GFP_KERNEL);
209 if (unlikely(!fields)) {
210 kfree(entry);
211 return NULL;
212 }
213 entry->rule.fields = fields;
214
215 return entry;
216 }
217
218 /* Unpack a filter field's string representation from user-space
219 * buffer. */
220 char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
221 {
222 char *str;
223
224 if (!*bufp || (len == 0) || (len > *remain))
225 return ERR_PTR(-EINVAL);
226
227 /* Of the currently implemented string fields, PATH_MAX
228 * defines the longest valid length.
229 */
230 if (len > PATH_MAX)
231 return ERR_PTR(-ENAMETOOLONG);
232
233 str = kmalloc(len + 1, GFP_KERNEL);
234 if (unlikely(!str))
235 return ERR_PTR(-ENOMEM);
236
237 memcpy(str, *bufp, len);
238 str[len] = 0;
239 *bufp += len;
240 *remain -= len;
241
242 return str;
243 }
244
245 /* Translate an inode field to kernel respresentation. */
246 static inline int audit_to_inode(struct audit_krule *krule,
247 struct audit_field *f)
248 {
249 if (krule->listnr != AUDIT_FILTER_EXIT ||
250 krule->watch || krule->inode_f || krule->tree)
251 return -EINVAL;
252
253 krule->inode_f = f;
254 return 0;
255 }
256
257 /* Translate a watch string to kernel respresentation. */
258 static int audit_to_watch(struct audit_krule *krule, char *path, int len,
259 u32 op)
260 {
261 struct audit_watch *watch;
262
263 if (!audit_ih)
264 return -EOPNOTSUPP;
265
266 if (path[0] != '/' || path[len-1] == '/' ||
267 krule->listnr != AUDIT_FILTER_EXIT ||
268 op & ~AUDIT_EQUAL ||
269 krule->inode_f || krule->watch || krule->tree)
270 return -EINVAL;
271
272 watch = audit_init_watch(path);
273 if (unlikely(IS_ERR(watch)))
274 return PTR_ERR(watch);
275
276 audit_get_watch(watch);
277 krule->watch = watch;
278
279 return 0;
280 }
281
282 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
283
284 int __init audit_register_class(int class, unsigned *list)
285 {
286 __u32 *p = kzalloc(AUDIT_BITMASK_SIZE * sizeof(__u32), GFP_KERNEL);
287 if (!p)
288 return -ENOMEM;
289 while (*list != ~0U) {
290 unsigned n = *list++;
291 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
292 kfree(p);
293 return -EINVAL;
294 }
295 p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
296 }
297 if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
298 kfree(p);
299 return -EINVAL;
300 }
301 classes[class] = p;
302 return 0;
303 }
304
305 int audit_match_class(int class, unsigned syscall)
306 {
307 if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
308 return 0;
309 if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
310 return 0;
311 return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
312 }
313
314 #ifdef CONFIG_AUDITSYSCALL
315 static inline int audit_match_class_bits(int class, u32 *mask)
316 {
317 int i;
318
319 if (classes[class]) {
320 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
321 if (mask[i] & classes[class][i])
322 return 0;
323 }
324 return 1;
325 }
326
327 static int audit_match_signal(struct audit_entry *entry)
328 {
329 struct audit_field *arch = entry->rule.arch_f;
330
331 if (!arch) {
332 /* When arch is unspecified, we must check both masks on biarch
333 * as syscall number alone is ambiguous. */
334 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
335 entry->rule.mask) &&
336 audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
337 entry->rule.mask));
338 }
339
340 switch(audit_classify_arch(arch->val)) {
341 case 0: /* native */
342 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
343 entry->rule.mask));
344 case 1: /* 32bit on biarch */
345 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
346 entry->rule.mask));
347 default:
348 return 1;
349 }
350 }
351 #endif
352
353 /* Common user-space to kernel rule translation. */
354 static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule)
355 {
356 unsigned listnr;
357 struct audit_entry *entry;
358 int i, err;
359
360 err = -EINVAL;
361 listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
362 switch(listnr) {
363 default:
364 goto exit_err;
365 case AUDIT_FILTER_USER:
366 case AUDIT_FILTER_TYPE:
367 #ifdef CONFIG_AUDITSYSCALL
368 case AUDIT_FILTER_ENTRY:
369 case AUDIT_FILTER_EXIT:
370 case AUDIT_FILTER_TASK:
371 #endif
372 ;
373 }
374 if (unlikely(rule->action == AUDIT_POSSIBLE)) {
375 printk(KERN_ERR "AUDIT_POSSIBLE is deprecated\n");
376 goto exit_err;
377 }
378 if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
379 goto exit_err;
380 if (rule->field_count > AUDIT_MAX_FIELDS)
381 goto exit_err;
382
383 err = -ENOMEM;
384 entry = audit_init_entry(rule->field_count);
385 if (!entry)
386 goto exit_err;
387
388 entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
389 entry->rule.listnr = listnr;
390 entry->rule.action = rule->action;
391 entry->rule.field_count = rule->field_count;
392
393 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
394 entry->rule.mask[i] = rule->mask[i];
395
396 for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
397 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
398 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
399 __u32 *class;
400
401 if (!(*p & AUDIT_BIT(bit)))
402 continue;
403 *p &= ~AUDIT_BIT(bit);
404 class = classes[i];
405 if (class) {
406 int j;
407 for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
408 entry->rule.mask[j] |= class[j];
409 }
410 }
411
412 return entry;
413
414 exit_err:
415 return ERR_PTR(err);
416 }
417
418 /* Translate struct audit_rule to kernel's rule respresentation.
419 * Exists for backward compatibility with userspace. */
420 static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
421 {
422 struct audit_entry *entry;
423 struct audit_field *f;
424 int err = 0;
425 int i;
426
427 entry = audit_to_entry_common(rule);
428 if (IS_ERR(entry))
429 goto exit_nofree;
430
431 for (i = 0; i < rule->field_count; i++) {
432 struct audit_field *f = &entry->rule.fields[i];
433
434 f->op = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS);
435 f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS);
436 f->val = rule->values[i];
437
438 err = -EINVAL;
439 switch(f->type) {
440 default:
441 goto exit_free;
442 case AUDIT_PID:
443 case AUDIT_UID:
444 case AUDIT_EUID:
445 case AUDIT_SUID:
446 case AUDIT_FSUID:
447 case AUDIT_GID:
448 case AUDIT_EGID:
449 case AUDIT_SGID:
450 case AUDIT_FSGID:
451 case AUDIT_LOGINUID:
452 case AUDIT_PERS:
453 case AUDIT_MSGTYPE:
454 case AUDIT_PPID:
455 case AUDIT_DEVMAJOR:
456 case AUDIT_DEVMINOR:
457 case AUDIT_EXIT:
458 case AUDIT_SUCCESS:
459 /* bit ops are only useful on syscall args */
460 if (f->op == AUDIT_BIT_MASK ||
461 f->op == AUDIT_BIT_TEST) {
462 err = -EINVAL;
463 goto exit_free;
464 }
465 break;
466 case AUDIT_ARG0:
467 case AUDIT_ARG1:
468 case AUDIT_ARG2:
469 case AUDIT_ARG3:
470 break;
471 /* arch is only allowed to be = or != */
472 case AUDIT_ARCH:
473 if ((f->op != AUDIT_NOT_EQUAL) && (f->op != AUDIT_EQUAL)
474 && (f->op != AUDIT_NEGATE) && (f->op)) {
475 err = -EINVAL;
476 goto exit_free;
477 }
478 entry->rule.arch_f = f;
479 break;
480 case AUDIT_PERM:
481 if (f->val & ~15)
482 goto exit_free;
483 break;
484 case AUDIT_INODE:
485 err = audit_to_inode(&entry->rule, f);
486 if (err)
487 goto exit_free;
488 break;
489 }
490
491 entry->rule.vers_ops = (f->op & AUDIT_OPERATORS) ? 2 : 1;
492
493 /* Support for legacy operators where
494 * AUDIT_NEGATE bit signifies != and otherwise assumes == */
495 if (f->op & AUDIT_NEGATE)
496 f->op = AUDIT_NOT_EQUAL;
497 else if (!f->op)
498 f->op = AUDIT_EQUAL;
499 else if (f->op == AUDIT_OPERATORS) {
500 err = -EINVAL;
501 goto exit_free;
502 }
503 }
504
505 f = entry->rule.inode_f;
506 if (f) {
507 switch(f->op) {
508 case AUDIT_NOT_EQUAL:
509 entry->rule.inode_f = NULL;
510 case AUDIT_EQUAL:
511 break;
512 default:
513 err = -EINVAL;
514 goto exit_free;
515 }
516 }
517
518 exit_nofree:
519 return entry;
520
521 exit_free:
522 audit_free_rule(entry);
523 return ERR_PTR(err);
524 }
525
526 /* Translate struct audit_rule_data to kernel's rule respresentation. */
527 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
528 size_t datasz)
529 {
530 int err = 0;
531 struct audit_entry *entry;
532 struct audit_field *f;
533 void *bufp;
534 size_t remain = datasz - sizeof(struct audit_rule_data);
535 int i;
536 char *str;
537
538 entry = audit_to_entry_common((struct audit_rule *)data);
539 if (IS_ERR(entry))
540 goto exit_nofree;
541
542 bufp = data->buf;
543 entry->rule.vers_ops = 2;
544 for (i = 0; i < data->field_count; i++) {
545 struct audit_field *f = &entry->rule.fields[i];
546
547 err = -EINVAL;
548 if (!(data->fieldflags[i] & AUDIT_OPERATORS) ||
549 data->fieldflags[i] & ~AUDIT_OPERATORS)
550 goto exit_free;
551
552 f->op = data->fieldflags[i] & AUDIT_OPERATORS;
553 f->type = data->fields[i];
554 f->val = data->values[i];
555 f->se_str = NULL;
556 f->se_rule = NULL;
557 switch(f->type) {
558 case AUDIT_PID:
559 case AUDIT_UID:
560 case AUDIT_EUID:
561 case AUDIT_SUID:
562 case AUDIT_FSUID:
563 case AUDIT_GID:
564 case AUDIT_EGID:
565 case AUDIT_SGID:
566 case AUDIT_FSGID:
567 case AUDIT_LOGINUID:
568 case AUDIT_PERS:
569 case AUDIT_MSGTYPE:
570 case AUDIT_PPID:
571 case AUDIT_DEVMAJOR:
572 case AUDIT_DEVMINOR:
573 case AUDIT_EXIT:
574 case AUDIT_SUCCESS:
575 case AUDIT_ARG0:
576 case AUDIT_ARG1:
577 case AUDIT_ARG2:
578 case AUDIT_ARG3:
579 break;
580 case AUDIT_ARCH:
581 entry->rule.arch_f = f;
582 break;
583 case AUDIT_SUBJ_USER:
584 case AUDIT_SUBJ_ROLE:
585 case AUDIT_SUBJ_TYPE:
586 case AUDIT_SUBJ_SEN:
587 case AUDIT_SUBJ_CLR:
588 case AUDIT_OBJ_USER:
589 case AUDIT_OBJ_ROLE:
590 case AUDIT_OBJ_TYPE:
591 case AUDIT_OBJ_LEV_LOW:
592 case AUDIT_OBJ_LEV_HIGH:
593 str = audit_unpack_string(&bufp, &remain, f->val);
594 if (IS_ERR(str))
595 goto exit_free;
596 entry->rule.buflen += f->val;
597
598 err = selinux_audit_rule_init(f->type, f->op, str,
599 &f->se_rule);
600 /* Keep currently invalid fields around in case they
601 * become valid after a policy reload. */
602 if (err == -EINVAL) {
603 printk(KERN_WARNING "audit rule for selinux "
604 "\'%s\' is invalid\n", str);
605 err = 0;
606 }
607 if (err) {
608 kfree(str);
609 goto exit_free;
610 } else
611 f->se_str = str;
612 break;
613 case AUDIT_WATCH:
614 str = audit_unpack_string(&bufp, &remain, f->val);
615 if (IS_ERR(str))
616 goto exit_free;
617 entry->rule.buflen += f->val;
618
619 err = audit_to_watch(&entry->rule, str, f->val, f->op);
620 if (err) {
621 kfree(str);
622 goto exit_free;
623 }
624 break;
625 case AUDIT_DIR:
626 str = audit_unpack_string(&bufp, &remain, f->val);
627 if (IS_ERR(str))
628 goto exit_free;
629 entry->rule.buflen += f->val;
630
631 err = audit_make_tree(&entry->rule, str, f->op);
632 kfree(str);
633 if (err)
634 goto exit_free;
635 break;
636 case AUDIT_INODE:
637 err = audit_to_inode(&entry->rule, f);
638 if (err)
639 goto exit_free;
640 break;
641 case AUDIT_FILTERKEY:
642 err = -EINVAL;
643 if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
644 goto exit_free;
645 str = audit_unpack_string(&bufp, &remain, f->val);
646 if (IS_ERR(str))
647 goto exit_free;
648 entry->rule.buflen += f->val;
649 entry->rule.filterkey = str;
650 break;
651 case AUDIT_PERM:
652 if (f->val & ~15)
653 goto exit_free;
654 break;
655 default:
656 goto exit_free;
657 }
658 }
659
660 f = entry->rule.inode_f;
661 if (f) {
662 switch(f->op) {
663 case AUDIT_NOT_EQUAL:
664 entry->rule.inode_f = NULL;
665 case AUDIT_EQUAL:
666 break;
667 default:
668 err = -EINVAL;
669 goto exit_free;
670 }
671 }
672
673 exit_nofree:
674 return entry;
675
676 exit_free:
677 audit_free_rule(entry);
678 return ERR_PTR(err);
679 }
680
681 /* Pack a filter field's string representation into data block. */
682 static inline size_t audit_pack_string(void **bufp, const char *str)
683 {
684 size_t len = strlen(str);
685
686 memcpy(*bufp, str, len);
687 *bufp += len;
688
689 return len;
690 }
691
692 /* Translate kernel rule respresentation to struct audit_rule.
693 * Exists for backward compatibility with userspace. */
694 static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
695 {
696 struct audit_rule *rule;
697 int i;
698
699 rule = kzalloc(sizeof(*rule), GFP_KERNEL);
700 if (unlikely(!rule))
701 return NULL;
702
703 rule->flags = krule->flags | krule->listnr;
704 rule->action = krule->action;
705 rule->field_count = krule->field_count;
706 for (i = 0; i < rule->field_count; i++) {
707 rule->values[i] = krule->fields[i].val;
708 rule->fields[i] = krule->fields[i].type;
709
710 if (krule->vers_ops == 1) {
711 if (krule->fields[i].op & AUDIT_NOT_EQUAL)
712 rule->fields[i] |= AUDIT_NEGATE;
713 } else {
714 rule->fields[i] |= krule->fields[i].op;
715 }
716 }
717 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];
718
719 return rule;
720 }
721
722 /* Translate kernel rule respresentation to struct audit_rule_data. */
723 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
724 {
725 struct audit_rule_data *data;
726 void *bufp;
727 int i;
728
729 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
730 if (unlikely(!data))
731 return NULL;
732 memset(data, 0, sizeof(*data));
733
734 data->flags = krule->flags | krule->listnr;
735 data->action = krule->action;
736 data->field_count = krule->field_count;
737 bufp = data->buf;
738 for (i = 0; i < data->field_count; i++) {
739 struct audit_field *f = &krule->fields[i];
740
741 data->fields[i] = f->type;
742 data->fieldflags[i] = f->op;
743 switch(f->type) {
744 case AUDIT_SUBJ_USER:
745 case AUDIT_SUBJ_ROLE:
746 case AUDIT_SUBJ_TYPE:
747 case AUDIT_SUBJ_SEN:
748 case AUDIT_SUBJ_CLR:
749 case AUDIT_OBJ_USER:
750 case AUDIT_OBJ_ROLE:
751 case AUDIT_OBJ_TYPE:
752 case AUDIT_OBJ_LEV_LOW:
753 case AUDIT_OBJ_LEV_HIGH:
754 data->buflen += data->values[i] =
755 audit_pack_string(&bufp, f->se_str);
756 break;
757 case AUDIT_WATCH:
758 data->buflen += data->values[i] =
759 audit_pack_string(&bufp, krule->watch->path);
760 break;
761 case AUDIT_DIR:
762 data->buflen += data->values[i] =
763 audit_pack_string(&bufp,
764 audit_tree_path(krule->tree));
765 break;
766 case AUDIT_FILTERKEY:
767 data->buflen += data->values[i] =
768 audit_pack_string(&bufp, krule->filterkey);
769 break;
770 default:
771 data->values[i] = f->val;
772 }
773 }
774 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];
775
776 return data;
777 }
778
779 /* Compare two rules in kernel format. Considered success if rules
780 * don't match. */
781 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
782 {
783 int i;
784
785 if (a->flags != b->flags ||
786 a->listnr != b->listnr ||
787 a->action != b->action ||
788 a->field_count != b->field_count)
789 return 1;
790
791 for (i = 0; i < a->field_count; i++) {
792 if (a->fields[i].type != b->fields[i].type ||
793 a->fields[i].op != b->fields[i].op)
794 return 1;
795
796 switch(a->fields[i].type) {
797 case AUDIT_SUBJ_USER:
798 case AUDIT_SUBJ_ROLE:
799 case AUDIT_SUBJ_TYPE:
800 case AUDIT_SUBJ_SEN:
801 case AUDIT_SUBJ_CLR:
802 case AUDIT_OBJ_USER:
803 case AUDIT_OBJ_ROLE:
804 case AUDIT_OBJ_TYPE:
805 case AUDIT_OBJ_LEV_LOW:
806 case AUDIT_OBJ_LEV_HIGH:
807 if (strcmp(a->fields[i].se_str, b->fields[i].se_str))
808 return 1;
809 break;
810 case AUDIT_WATCH:
811 if (strcmp(a->watch->path, b->watch->path))
812 return 1;
813 break;
814 case AUDIT_DIR:
815 if (strcmp(audit_tree_path(a->tree),
816 audit_tree_path(b->tree)))
817 return 1;
818 break;
819 case AUDIT_FILTERKEY:
820 /* both filterkeys exist based on above type compare */
821 if (strcmp(a->filterkey, b->filterkey))
822 return 1;
823 break;
824 default:
825 if (a->fields[i].val != b->fields[i].val)
826 return 1;
827 }
828 }
829
830 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
831 if (a->mask[i] != b->mask[i])
832 return 1;
833
834 return 0;
835 }
836
837 /* Duplicate the given audit watch. The new watch's rules list is initialized
838 * to an empty list and wlist is undefined. */
839 static struct audit_watch *audit_dupe_watch(struct audit_watch *old)
840 {
841 char *path;
842 struct audit_watch *new;
843
844 path = kstrdup(old->path, GFP_KERNEL);
845 if (unlikely(!path))
846 return ERR_PTR(-ENOMEM);
847
848 new = audit_init_watch(path);
849 if (unlikely(IS_ERR(new))) {
850 kfree(path);
851 goto out;
852 }
853
854 new->dev = old->dev;
855 new->ino = old->ino;
856 get_inotify_watch(&old->parent->wdata);
857 new->parent = old->parent;
858
859 out:
860 return new;
861 }
862
863 /* Duplicate selinux field information. The se_rule is opaque, so must be
864 * re-initialized. */
865 static inline int audit_dupe_selinux_field(struct audit_field *df,
866 struct audit_field *sf)
867 {
868 int ret = 0;
869 char *se_str;
870
871 /* our own copy of se_str */
872 se_str = kstrdup(sf->se_str, GFP_KERNEL);
873 if (unlikely(!se_str))
874 return -ENOMEM;
875 df->se_str = se_str;
876
877 /* our own (refreshed) copy of se_rule */
878 ret = selinux_audit_rule_init(df->type, df->op, df->se_str,
879 &df->se_rule);
880 /* Keep currently invalid fields around in case they
881 * become valid after a policy reload. */
882 if (ret == -EINVAL) {
883 printk(KERN_WARNING "audit rule for selinux \'%s\' is "
884 "invalid\n", df->se_str);
885 ret = 0;
886 }
887
888 return ret;
889 }
890
891 /* Duplicate an audit rule. This will be a deep copy with the exception
892 * of the watch - that pointer is carried over. The selinux specific fields
893 * will be updated in the copy. The point is to be able to replace the old
894 * rule with the new rule in the filterlist, then free the old rule.
895 * The rlist element is undefined; list manipulations are handled apart from
896 * the initial copy. */
897 static struct audit_entry *audit_dupe_rule(struct audit_krule *old,
898 struct audit_watch *watch)
899 {
900 u32 fcount = old->field_count;
901 struct audit_entry *entry;
902 struct audit_krule *new;
903 char *fk;
904 int i, err = 0;
905
906 entry = audit_init_entry(fcount);
907 if (unlikely(!entry))
908 return ERR_PTR(-ENOMEM);
909
910 new = &entry->rule;
911 new->vers_ops = old->vers_ops;
912 new->flags = old->flags;
913 new->listnr = old->listnr;
914 new->action = old->action;
915 for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
916 new->mask[i] = old->mask[i];
917 new->buflen = old->buflen;
918 new->inode_f = old->inode_f;
919 new->watch = NULL;
920 new->field_count = old->field_count;
921 /*
922 * note that we are OK with not refcounting here; audit_match_tree()
923 * never dereferences tree and we can't get false positives there
924 * since we'd have to have rule gone from the list *and* removed
925 * before the chunks found by lookup had been allocated, i.e. before
926 * the beginning of list scan.
927 */
928 new->tree = old->tree;
929 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
930
931 /* deep copy this information, updating the se_rule fields, because
932 * the originals will all be freed when the old rule is freed. */
933 for (i = 0; i < fcount; i++) {
934 switch (new->fields[i].type) {
935 case AUDIT_SUBJ_USER:
936 case AUDIT_SUBJ_ROLE:
937 case AUDIT_SUBJ_TYPE:
938 case AUDIT_SUBJ_SEN:
939 case AUDIT_SUBJ_CLR:
940 case AUDIT_OBJ_USER:
941 case AUDIT_OBJ_ROLE:
942 case AUDIT_OBJ_TYPE:
943 case AUDIT_OBJ_LEV_LOW:
944 case AUDIT_OBJ_LEV_HIGH:
945 err = audit_dupe_selinux_field(&new->fields[i],
946 &old->fields[i]);
947 break;
948 case AUDIT_FILTERKEY:
949 fk = kstrdup(old->filterkey, GFP_KERNEL);
950 if (unlikely(!fk))
951 err = -ENOMEM;
952 else
953 new->filterkey = fk;
954 }
955 if (err) {
956 audit_free_rule(entry);
957 return ERR_PTR(err);
958 }
959 }
960
961 if (watch) {
962 audit_get_watch(watch);
963 new->watch = watch;
964 }
965
966 return entry;
967 }
968
969 /* Update inode info in audit rules based on filesystem event. */
970 static void audit_update_watch(struct audit_parent *parent,
971 const char *dname, dev_t dev,
972 unsigned long ino, unsigned invalidating)
973 {
974 struct audit_watch *owatch, *nwatch, *nextw;
975 struct audit_krule *r, *nextr;
976 struct audit_entry *oentry, *nentry;
977 struct audit_buffer *ab;
978
979 mutex_lock(&audit_filter_mutex);
980 list_for_each_entry_safe(owatch, nextw, &parent->watches, wlist) {
981 if (audit_compare_dname_path(dname, owatch->path, NULL))
982 continue;
983
984 /* If the update involves invalidating rules, do the inode-based
985 * filtering now, so we don't omit records. */
986 if (invalidating && current->audit_context &&
987 audit_filter_inodes(current, current->audit_context) == AUDIT_RECORD_CONTEXT)
988 audit_set_auditable(current->audit_context);
989
990 nwatch = audit_dupe_watch(owatch);
991 if (unlikely(IS_ERR(nwatch))) {
992 mutex_unlock(&audit_filter_mutex);
993 audit_panic("error updating watch, skipping");
994 return;
995 }
996 nwatch->dev = dev;
997 nwatch->ino = ino;
998
999 list_for_each_entry_safe(r, nextr, &owatch->rules, rlist) {
1000
1001 oentry = container_of(r, struct audit_entry, rule);
1002 list_del(&oentry->rule.rlist);
1003 list_del_rcu(&oentry->list);
1004
1005 nentry = audit_dupe_rule(&oentry->rule, nwatch);
1006 if (unlikely(IS_ERR(nentry)))
1007 audit_panic("error updating watch, removing");
1008 else {
1009 int h = audit_hash_ino((u32)ino);
1010 list_add(&nentry->rule.rlist, &nwatch->rules);
1011 list_add_rcu(&nentry->list, &audit_inode_hash[h]);
1012 }
1013
1014 call_rcu(&oentry->rcu, audit_free_rule_rcu);
1015 }
1016
1017 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1018 audit_log_format(ab, "op=updated rules specifying path=");
1019 audit_log_untrustedstring(ab, owatch->path);
1020 audit_log_format(ab, " with dev=%u ino=%lu\n", dev, ino);
1021 audit_log_format(ab, " list=%d res=1", r->listnr);
1022 audit_log_end(ab);
1023
1024 audit_remove_watch(owatch);
1025 goto add_watch_to_parent; /* event applies to a single watch */
1026 }
1027 mutex_unlock(&audit_filter_mutex);
1028 return;
1029
1030 add_watch_to_parent:
1031 list_add(&nwatch->wlist, &parent->watches);
1032 mutex_unlock(&audit_filter_mutex);
1033 return;
1034 }
1035
1036 /* Remove all watches & rules associated with a parent that is going away. */
1037 static void audit_remove_parent_watches(struct audit_parent *parent)
1038 {
1039 struct audit_watch *w, *nextw;
1040 struct audit_krule *r, *nextr;
1041 struct audit_entry *e;
1042 struct audit_buffer *ab;
1043
1044 mutex_lock(&audit_filter_mutex);
1045 parent->flags |= AUDIT_PARENT_INVALID;
1046 list_for_each_entry_safe(w, nextw, &parent->watches, wlist) {
1047 list_for_each_entry_safe(r, nextr, &w->rules, rlist) {
1048 e = container_of(r, struct audit_entry, rule);
1049
1050 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1051 audit_log_format(ab, "op=remove rule path=");
1052 audit_log_untrustedstring(ab, w->path);
1053 if (r->filterkey) {
1054 audit_log_format(ab, " key=");
1055 audit_log_untrustedstring(ab, r->filterkey);
1056 } else
1057 audit_log_format(ab, " key=(null)");
1058 audit_log_format(ab, " list=%d res=1", r->listnr);
1059 audit_log_end(ab);
1060
1061 list_del(&r->rlist);
1062 list_del_rcu(&e->list);
1063 call_rcu(&e->rcu, audit_free_rule_rcu);
1064 }
1065 audit_remove_watch(w);
1066 }
1067 mutex_unlock(&audit_filter_mutex);
1068 }
1069
1070 /* Unregister inotify watches for parents on in_list.
1071 * Generates an IN_IGNORED event. */
1072 static void audit_inotify_unregister(struct list_head *in_list)
1073 {
1074 struct audit_parent *p, *n;
1075
1076 list_for_each_entry_safe(p, n, in_list, ilist) {
1077 list_del(&p->ilist);
1078 inotify_rm_watch(audit_ih, &p->wdata);
1079 /* the put matching the get in audit_do_del_rule() */
1080 put_inotify_watch(&p->wdata);
1081 }
1082 }
1083
1084 /* Find an existing audit rule.
1085 * Caller must hold audit_filter_mutex to prevent stale rule data. */
1086 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
1087 struct list_head *list)
1088 {
1089 struct audit_entry *e, *found = NULL;
1090 int h;
1091
1092 if (entry->rule.watch) {
1093 /* we don't know the inode number, so must walk entire hash */
1094 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
1095 list = &audit_inode_hash[h];
1096 list_for_each_entry(e, list, list)
1097 if (!audit_compare_rule(&entry->rule, &e->rule)) {
1098 found = e;
1099 goto out;
1100 }
1101 }
1102 goto out;
1103 }
1104
1105 list_for_each_entry(e, list, list)
1106 if (!audit_compare_rule(&entry->rule, &e->rule)) {
1107 found = e;
1108 goto out;
1109 }
1110
1111 out:
1112 return found;
1113 }
1114
1115 /* Get path information necessary for adding watches. */
1116 static int audit_get_nd(char *path, struct nameidata **ndp,
1117 struct nameidata **ndw)
1118 {
1119 struct nameidata *ndparent, *ndwatch;
1120 int err;
1121
1122 ndparent = kmalloc(sizeof(*ndparent), GFP_KERNEL);
1123 if (unlikely(!ndparent))
1124 return -ENOMEM;
1125
1126 ndwatch = kmalloc(sizeof(*ndwatch), GFP_KERNEL);
1127 if (unlikely(!ndwatch)) {
1128 kfree(ndparent);
1129 return -ENOMEM;
1130 }
1131
1132 err = path_lookup(path, LOOKUP_PARENT, ndparent);
1133 if (err) {
1134 kfree(ndparent);
1135 kfree(ndwatch);
1136 return err;
1137 }
1138
1139 err = path_lookup(path, 0, ndwatch);
1140 if (err) {
1141 kfree(ndwatch);
1142 ndwatch = NULL;
1143 }
1144
1145 *ndp = ndparent;
1146 *ndw = ndwatch;
1147
1148 return 0;
1149 }
1150
1151 /* Release resources used for watch path information. */
1152 static void audit_put_nd(struct nameidata *ndp, struct nameidata *ndw)
1153 {
1154 if (ndp) {
1155 path_release(ndp);
1156 kfree(ndp);
1157 }
1158 if (ndw) {
1159 path_release(ndw);
1160 kfree(ndw);
1161 }
1162 }
1163
1164 /* Associate the given rule with an existing parent inotify_watch.
1165 * Caller must hold audit_filter_mutex. */
1166 static void audit_add_to_parent(struct audit_krule *krule,
1167 struct audit_parent *parent)
1168 {
1169 struct audit_watch *w, *watch = krule->watch;
1170 int watch_found = 0;
1171
1172 list_for_each_entry(w, &parent->watches, wlist) {
1173 if (strcmp(watch->path, w->path))
1174 continue;
1175
1176 watch_found = 1;
1177
1178 /* put krule's and initial refs to temporary watch */
1179 audit_put_watch(watch);
1180 audit_put_watch(watch);
1181
1182 audit_get_watch(w);
1183 krule->watch = watch = w;
1184 break;
1185 }
1186
1187 if (!watch_found) {
1188 get_inotify_watch(&parent->wdata);
1189 watch->parent = parent;
1190
1191 list_add(&watch->wlist, &parent->watches);
1192 }
1193 list_add(&krule->rlist, &watch->rules);
1194 }
1195
1196 /* Find a matching watch entry, or add this one.
1197 * Caller must hold audit_filter_mutex. */
1198 static int audit_add_watch(struct audit_krule *krule, struct nameidata *ndp,
1199 struct nameidata *ndw)
1200 {
1201 struct audit_watch *watch = krule->watch;
1202 struct inotify_watch *i_watch;
1203 struct audit_parent *parent;
1204 int ret = 0;
1205
1206 /* update watch filter fields */
1207 if (ndw) {
1208 watch->dev = ndw->dentry->d_inode->i_sb->s_dev;
1209 watch->ino = ndw->dentry->d_inode->i_ino;
1210 }
1211
1212 /* The audit_filter_mutex must not be held during inotify calls because
1213 * we hold it during inotify event callback processing. If an existing
1214 * inotify watch is found, inotify_find_watch() grabs a reference before
1215 * returning.
1216 */
1217 mutex_unlock(&audit_filter_mutex);
1218
1219 if (inotify_find_watch(audit_ih, ndp->dentry->d_inode, &i_watch) < 0) {
1220 parent = audit_init_parent(ndp);
1221 if (IS_ERR(parent)) {
1222 /* caller expects mutex locked */
1223 mutex_lock(&audit_filter_mutex);
1224 return PTR_ERR(parent);
1225 }
1226 } else
1227 parent = container_of(i_watch, struct audit_parent, wdata);
1228
1229 mutex_lock(&audit_filter_mutex);
1230
1231 /* parent was moved before we took audit_filter_mutex */
1232 if (parent->flags & AUDIT_PARENT_INVALID)
1233 ret = -ENOENT;
1234 else
1235 audit_add_to_parent(krule, parent);
1236
1237 /* match get in audit_init_parent or inotify_find_watch */
1238 put_inotify_watch(&parent->wdata);
1239 return ret;
1240 }
1241
1242 /* Add rule to given filterlist if not a duplicate. */
1243 static inline int audit_add_rule(struct audit_entry *entry,
1244 struct list_head *list)
1245 {
1246 struct audit_entry *e;
1247 struct audit_field *inode_f = entry->rule.inode_f;
1248 struct audit_watch *watch = entry->rule.watch;
1249 struct audit_tree *tree = entry->rule.tree;
1250 struct nameidata *ndp = NULL, *ndw = NULL;
1251 int h, err;
1252 #ifdef CONFIG_AUDITSYSCALL
1253 int dont_count = 0;
1254
1255 /* If either of these, don't count towards total */
1256 if (entry->rule.listnr == AUDIT_FILTER_USER ||
1257 entry->rule.listnr == AUDIT_FILTER_TYPE)
1258 dont_count = 1;
1259 #endif
1260
1261 if (inode_f) {
1262 h = audit_hash_ino(inode_f->val);
1263 list = &audit_inode_hash[h];
1264 }
1265
1266 mutex_lock(&audit_filter_mutex);
1267 e = audit_find_rule(entry, list);
1268 mutex_unlock(&audit_filter_mutex);
1269 if (e) {
1270 err = -EEXIST;
1271 /* normally audit_add_tree_rule() will free it on failure */
1272 if (tree)
1273 audit_put_tree(tree);
1274 goto error;
1275 }
1276
1277 /* Avoid calling path_lookup under audit_filter_mutex. */
1278 if (watch) {
1279 err = audit_get_nd(watch->path, &ndp, &ndw);
1280 if (err)
1281 goto error;
1282 }
1283
1284 mutex_lock(&audit_filter_mutex);
1285 if (watch) {
1286 /* audit_filter_mutex is dropped and re-taken during this call */
1287 err = audit_add_watch(&entry->rule, ndp, ndw);
1288 if (err) {
1289 mutex_unlock(&audit_filter_mutex);
1290 goto error;
1291 }
1292 h = audit_hash_ino((u32)watch->ino);
1293 list = &audit_inode_hash[h];
1294 }
1295 if (tree) {
1296 err = audit_add_tree_rule(&entry->rule);
1297 if (err) {
1298 mutex_unlock(&audit_filter_mutex);
1299 goto error;
1300 }
1301 }
1302
1303 if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
1304 list_add_rcu(&entry->list, list);
1305 entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
1306 } else {
1307 list_add_tail_rcu(&entry->list, list);
1308 }
1309 #ifdef CONFIG_AUDITSYSCALL
1310 if (!dont_count)
1311 audit_n_rules++;
1312
1313 if (!audit_match_signal(entry))
1314 audit_signals++;
1315 #endif
1316 mutex_unlock(&audit_filter_mutex);
1317
1318 audit_put_nd(ndp, ndw); /* NULL args OK */
1319 return 0;
1320
1321 error:
1322 audit_put_nd(ndp, ndw); /* NULL args OK */
1323 if (watch)
1324 audit_put_watch(watch); /* tmp watch, matches initial get */
1325 return err;
1326 }
1327
1328 /* Remove an existing rule from filterlist. */
1329 static inline int audit_del_rule(struct audit_entry *entry,
1330 struct list_head *list)
1331 {
1332 struct audit_entry *e;
1333 struct audit_field *inode_f = entry->rule.inode_f;
1334 struct audit_watch *watch, *tmp_watch = entry->rule.watch;
1335 struct audit_tree *tree = entry->rule.tree;
1336 LIST_HEAD(inotify_list);
1337 int h, ret = 0;
1338 #ifdef CONFIG_AUDITSYSCALL
1339 int dont_count = 0;
1340
1341 /* If either of these, don't count towards total */
1342 if (entry->rule.listnr == AUDIT_FILTER_USER ||
1343 entry->rule.listnr == AUDIT_FILTER_TYPE)
1344 dont_count = 1;
1345 #endif
1346
1347 if (inode_f) {
1348 h = audit_hash_ino(inode_f->val);
1349 list = &audit_inode_hash[h];
1350 }
1351
1352 mutex_lock(&audit_filter_mutex);
1353 e = audit_find_rule(entry, list);
1354 if (!e) {
1355 mutex_unlock(&audit_filter_mutex);
1356 ret = -ENOENT;
1357 goto out;
1358 }
1359
1360 watch = e->rule.watch;
1361 if (watch) {
1362 struct audit_parent *parent = watch->parent;
1363
1364 list_del(&e->rule.rlist);
1365
1366 if (list_empty(&watch->rules)) {
1367 audit_remove_watch(watch);
1368
1369 if (list_empty(&parent->watches)) {
1370 /* Put parent on the inotify un-registration
1371 * list. Grab a reference before releasing
1372 * audit_filter_mutex, to be released in
1373 * audit_inotify_unregister(). */
1374 list_add(&parent->ilist, &inotify_list);
1375 get_inotify_watch(&parent->wdata);
1376 }
1377 }
1378 }
1379
1380 if (e->rule.tree)
1381 audit_remove_tree_rule(&e->rule);
1382
1383 list_del_rcu(&e->list);
1384 call_rcu(&e->rcu, audit_free_rule_rcu);
1385
1386 #ifdef CONFIG_AUDITSYSCALL
1387 if (!dont_count)
1388 audit_n_rules--;
1389
1390 if (!audit_match_signal(entry))
1391 audit_signals--;
1392 #endif
1393 mutex_unlock(&audit_filter_mutex);
1394
1395 if (!list_empty(&inotify_list))
1396 audit_inotify_unregister(&inotify_list);
1397
1398 out:
1399 if (tmp_watch)
1400 audit_put_watch(tmp_watch); /* match initial get */
1401 if (tree)
1402 audit_put_tree(tree); /* that's the temporary one */
1403
1404 return ret;
1405 }
1406
1407 /* List rules using struct audit_rule. Exists for backward
1408 * compatibility with userspace. */
1409 static void audit_list(int pid, int seq, struct sk_buff_head *q)
1410 {
1411 struct sk_buff *skb;
1412 struct audit_entry *entry;
1413 int i;
1414
1415 /* This is a blocking read, so use audit_filter_mutex instead of rcu
1416 * iterator to sync with list writers. */
1417 for (i=0; i<AUDIT_NR_FILTERS; i++) {
1418 list_for_each_entry(entry, &audit_filter_list[i], list) {
1419 struct audit_rule *rule;
1420
1421 rule = audit_krule_to_rule(&entry->rule);
1422 if (unlikely(!rule))
1423 break;
1424 skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1425 rule, sizeof(*rule));
1426 if (skb)
1427 skb_queue_tail(q, skb);
1428 kfree(rule);
1429 }
1430 }
1431 for (i = 0; i < AUDIT_INODE_BUCKETS; i++) {
1432 list_for_each_entry(entry, &audit_inode_hash[i], list) {
1433 struct audit_rule *rule;
1434
1435 rule = audit_krule_to_rule(&entry->rule);
1436 if (unlikely(!rule))
1437 break;
1438 skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
1439 rule, sizeof(*rule));
1440 if (skb)
1441 skb_queue_tail(q, skb);
1442 kfree(rule);
1443 }
1444 }
1445 skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
1446 if (skb)
1447 skb_queue_tail(q, skb);
1448 }
1449
1450 /* List rules using struct audit_rule_data. */
1451 static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
1452 {
1453 struct sk_buff *skb;
1454 struct audit_entry *e;
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(e, &audit_filter_list[i], list) {
1461 struct audit_rule_data *data;
1462
1463 data = audit_krule_to_data(&e->rule);
1464 if (unlikely(!data))
1465 break;
1466 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1467 data, sizeof(*data) + data->buflen);
1468 if (skb)
1469 skb_queue_tail(q, skb);
1470 kfree(data);
1471 }
1472 }
1473 for (i=0; i< AUDIT_INODE_BUCKETS; i++) {
1474 list_for_each_entry(e, &audit_inode_hash[i], list) {
1475 struct audit_rule_data *data;
1476
1477 data = audit_krule_to_data(&e->rule);
1478 if (unlikely(!data))
1479 break;
1480 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
1481 data, sizeof(*data) + data->buflen);
1482 if (skb)
1483 skb_queue_tail(q, skb);
1484 kfree(data);
1485 }
1486 }
1487 skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
1488 if (skb)
1489 skb_queue_tail(q, skb);
1490 }
1491
1492 /* Log rule additions and removals */
1493 static void audit_log_rule_change(uid_t loginuid, u32 sid, char *action,
1494 struct audit_krule *rule, int res)
1495 {
1496 struct audit_buffer *ab;
1497
1498 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
1499 if (!ab)
1500 return;
1501 audit_log_format(ab, "auid=%u", loginuid);
1502 if (sid) {
1503 char *ctx = NULL;
1504 u32 len;
1505 if (selinux_sid_to_string(sid, &ctx, &len))
1506 audit_log_format(ab, " ssid=%u", sid);
1507 else
1508 audit_log_format(ab, " subj=%s", ctx);
1509 kfree(ctx);
1510 }
1511 audit_log_format(ab, " op=%s rule key=", action);
1512 if (rule->filterkey)
1513 audit_log_untrustedstring(ab, rule->filterkey);
1514 else
1515 audit_log_format(ab, "(null)");
1516 audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
1517 audit_log_end(ab);
1518 }
1519
1520 /**
1521 * audit_receive_filter - apply all rules to the specified message type
1522 * @type: audit message type
1523 * @pid: target pid for netlink audit messages
1524 * @uid: target uid for netlink audit messages
1525 * @seq: netlink audit message sequence (serial) number
1526 * @data: payload data
1527 * @datasz: size of payload data
1528 * @loginuid: loginuid of sender
1529 * @sid: SE Linux Security ID of sender
1530 */
1531 int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
1532 size_t datasz, uid_t loginuid, u32 sid)
1533 {
1534 struct task_struct *tsk;
1535 struct audit_netlink_list *dest;
1536 int err = 0;
1537 struct audit_entry *entry;
1538
1539 switch (type) {
1540 case AUDIT_LIST:
1541 case AUDIT_LIST_RULES:
1542 /* We can't just spew out the rules here because we might fill
1543 * the available socket buffer space and deadlock waiting for
1544 * auditctl to read from it... which isn't ever going to
1545 * happen if we're actually running in the context of auditctl
1546 * trying to _send_ the stuff */
1547
1548 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
1549 if (!dest)
1550 return -ENOMEM;
1551 dest->pid = pid;
1552 skb_queue_head_init(&dest->q);
1553
1554 mutex_lock(&audit_filter_mutex);
1555 if (type == AUDIT_LIST)
1556 audit_list(pid, seq, &dest->q);
1557 else
1558 audit_list_rules(pid, seq, &dest->q);
1559 mutex_unlock(&audit_filter_mutex);
1560
1561 tsk = kthread_run(audit_send_list, dest, "audit_send_list");
1562 if (IS_ERR(tsk)) {
1563 skb_queue_purge(&dest->q);
1564 kfree(dest);
1565 err = PTR_ERR(tsk);
1566 }
1567 break;
1568 case AUDIT_ADD:
1569 case AUDIT_ADD_RULE:
1570 if (type == AUDIT_ADD)
1571 entry = audit_rule_to_entry(data);
1572 else
1573 entry = audit_data_to_entry(data, datasz);
1574 if (IS_ERR(entry))
1575 return PTR_ERR(entry);
1576
1577 err = audit_add_rule(entry,
1578 &audit_filter_list[entry->rule.listnr]);
1579 audit_log_rule_change(loginuid, sid, "add", &entry->rule, !err);
1580
1581 if (err)
1582 audit_free_rule(entry);
1583 break;
1584 case AUDIT_DEL:
1585 case AUDIT_DEL_RULE:
1586 if (type == AUDIT_DEL)
1587 entry = audit_rule_to_entry(data);
1588 else
1589 entry = audit_data_to_entry(data, datasz);
1590 if (IS_ERR(entry))
1591 return PTR_ERR(entry);
1592
1593 err = audit_del_rule(entry,
1594 &audit_filter_list[entry->rule.listnr]);
1595 audit_log_rule_change(loginuid, sid, "remove", &entry->rule,
1596 !err);
1597
1598 audit_free_rule(entry);
1599 break;
1600 default:
1601 return -EINVAL;
1602 }
1603
1604 return err;
1605 }
1606
1607 int audit_comparator(const u32 left, const u32 op, const u32 right)
1608 {
1609 switch (op) {
1610 case AUDIT_EQUAL:
1611 return (left == right);
1612 case AUDIT_NOT_EQUAL:
1613 return (left != right);
1614 case AUDIT_LESS_THAN:
1615 return (left < right);
1616 case AUDIT_LESS_THAN_OR_EQUAL:
1617 return (left <= right);
1618 case AUDIT_GREATER_THAN:
1619 return (left > right);
1620 case AUDIT_GREATER_THAN_OR_EQUAL:
1621 return (left >= right);
1622 case AUDIT_BIT_MASK:
1623 return (left & right);
1624 case AUDIT_BIT_TEST:
1625 return ((left & right) == right);
1626 }
1627 BUG();
1628 return 0;
1629 }
1630
1631 /* Compare given dentry name with last component in given path,
1632 * return of 0 indicates a match. */
1633 int audit_compare_dname_path(const char *dname, const char *path,
1634 int *dirlen)
1635 {
1636 int dlen, plen;
1637 const char *p;
1638
1639 if (!dname || !path)
1640 return 1;
1641
1642 dlen = strlen(dname);
1643 plen = strlen(path);
1644 if (plen < dlen)
1645 return 1;
1646
1647 /* disregard trailing slashes */
1648 p = path + plen - 1;
1649 while ((*p == '/') && (p > path))
1650 p--;
1651
1652 /* find last path component */
1653 p = p - dlen + 1;
1654 if (p < path)
1655 return 1;
1656 else if (p > path) {
1657 if (*--p != '/')
1658 return 1;
1659 else
1660 p++;
1661 }
1662
1663 /* return length of path's directory component */
1664 if (dirlen)
1665 *dirlen = p - path;
1666 return strncmp(p, dname, dlen);
1667 }
1668
1669 static int audit_filter_user_rules(struct netlink_skb_parms *cb,
1670 struct audit_krule *rule,
1671 enum audit_state *state)
1672 {
1673 int i;
1674
1675 for (i = 0; i < rule->field_count; i++) {
1676 struct audit_field *f = &rule->fields[i];
1677 int result = 0;
1678
1679 switch (f->type) {
1680 case AUDIT_PID:
1681 result = audit_comparator(cb->creds.pid, f->op, f->val);
1682 break;
1683 case AUDIT_UID:
1684 result = audit_comparator(cb->creds.uid, f->op, f->val);
1685 break;
1686 case AUDIT_GID:
1687 result = audit_comparator(cb->creds.gid, f->op, f->val);
1688 break;
1689 case AUDIT_LOGINUID:
1690 result = audit_comparator(cb->loginuid, f->op, f->val);
1691 break;
1692 }
1693
1694 if (!result)
1695 return 0;
1696 }
1697 switch (rule->action) {
1698 case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
1699 case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
1700 }
1701 return 1;
1702 }
1703
1704 int audit_filter_user(struct netlink_skb_parms *cb, int type)
1705 {
1706 enum audit_state state = AUDIT_DISABLED;
1707 struct audit_entry *e;
1708 int ret = 1;
1709
1710 rcu_read_lock();
1711 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
1712 if (audit_filter_user_rules(cb, &e->rule, &state)) {
1713 if (state == AUDIT_DISABLED)
1714 ret = 0;
1715 break;
1716 }
1717 }
1718 rcu_read_unlock();
1719
1720 return ret; /* Audit by default */
1721 }
1722
1723 int audit_filter_type(int type)
1724 {
1725 struct audit_entry *e;
1726 int result = 0;
1727
1728 rcu_read_lock();
1729 if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
1730 goto unlock_and_return;
1731
1732 list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
1733 list) {
1734 int i;
1735 for (i = 0; i < e->rule.field_count; i++) {
1736 struct audit_field *f = &e->rule.fields[i];
1737 if (f->type == AUDIT_MSGTYPE) {
1738 result = audit_comparator(type, f->op, f->val);
1739 if (!result)
1740 break;
1741 }
1742 }
1743 if (result)
1744 goto unlock_and_return;
1745 }
1746 unlock_and_return:
1747 rcu_read_unlock();
1748 return result;
1749 }
1750
1751 /* Check to see if the rule contains any selinux fields. Returns 1 if there
1752 are selinux fields specified in the rule, 0 otherwise. */
1753 static inline int audit_rule_has_selinux(struct audit_krule *rule)
1754 {
1755 int i;
1756
1757 for (i = 0; i < rule->field_count; i++) {
1758 struct audit_field *f = &rule->fields[i];
1759 switch (f->type) {
1760 case AUDIT_SUBJ_USER:
1761 case AUDIT_SUBJ_ROLE:
1762 case AUDIT_SUBJ_TYPE:
1763 case AUDIT_SUBJ_SEN:
1764 case AUDIT_SUBJ_CLR:
1765 case AUDIT_OBJ_USER:
1766 case AUDIT_OBJ_ROLE:
1767 case AUDIT_OBJ_TYPE:
1768 case AUDIT_OBJ_LEV_LOW:
1769 case AUDIT_OBJ_LEV_HIGH:
1770 return 1;
1771 }
1772 }
1773
1774 return 0;
1775 }
1776
1777 /* This function will re-initialize the se_rule field of all applicable rules.
1778 * It will traverse the filter lists serarching for rules that contain selinux
1779 * specific filter fields. When such a rule is found, it is copied, the
1780 * selinux field is re-initialized, and the old rule is replaced with the
1781 * updated rule. */
1782 int selinux_audit_rule_update(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 (!audit_rule_has_selinux(&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 (unlikely(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 selinux 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 }
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