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1 | #include "audit.h" |
2 | #include <linux/fsnotify_backend.h> |
3 | #include <linux/namei.h> |
4 | #include <linux/mount.h> |
5 | #include <linux/kthread.h> |
6 | #include <linux/slab.h> |
7 | |
8 | struct audit_tree; |
9 | struct audit_chunk; |
10 | |
11 | struct audit_tree { |
12 | atomic_t count; |
13 | int goner; |
14 | struct audit_chunk *root; |
15 | struct list_head chunks; |
16 | struct list_head rules; |
17 | struct list_head list; |
18 | struct list_head same_root; |
19 | struct rcu_head head; |
20 | char pathname[]; |
21 | }; |
22 | |
23 | struct audit_chunk { |
24 | struct list_head hash; |
25 | struct fsnotify_mark mark; |
26 | struct list_head trees; /* with root here */ |
27 | int dead; |
28 | int count; |
29 | atomic_long_t refs; |
30 | struct rcu_head head; |
31 | struct node { |
32 | struct list_head list; |
33 | struct audit_tree *owner; |
34 | unsigned index; /* index; upper bit indicates 'will prune' */ |
35 | } owners[]; |
36 | }; |
37 | |
38 | static LIST_HEAD(tree_list); |
39 | static LIST_HEAD(prune_list); |
40 | |
41 | /* |
42 | * One struct chunk is attached to each inode of interest. |
43 | * We replace struct chunk on tagging/untagging. |
44 | * Rules have pointer to struct audit_tree. |
45 | * Rules have struct list_head rlist forming a list of rules over |
46 | * the same tree. |
47 | * References to struct chunk are collected at audit_inode{,_child}() |
48 | * time and used in AUDIT_TREE rule matching. |
49 | * These references are dropped at the same time we are calling |
50 | * audit_free_names(), etc. |
51 | * |
52 | * Cyclic lists galore: |
53 | * tree.chunks anchors chunk.owners[].list hash_lock |
54 | * tree.rules anchors rule.rlist audit_filter_mutex |
55 | * chunk.trees anchors tree.same_root hash_lock |
56 | * chunk.hash is a hash with middle bits of watch.inode as |
57 | * a hash function. RCU, hash_lock |
58 | * |
59 | * tree is refcounted; one reference for "some rules on rules_list refer to |
60 | * it", one for each chunk with pointer to it. |
61 | * |
62 | * chunk is refcounted by embedded fsnotify_mark + .refs (non-zero refcount |
63 | * of watch contributes 1 to .refs). |
64 | * |
65 | * node.index allows to get from node.list to containing chunk. |
66 | * MSB of that sucker is stolen to mark taggings that we might have to |
67 | * revert - several operations have very unpleasant cleanup logics and |
68 | * that makes a difference. Some. |
69 | */ |
70 | |
71 | static struct fsnotify_group *audit_tree_group; |
72 | |
73 | static struct audit_tree *alloc_tree(const char *s) |
74 | { |
75 | struct audit_tree *tree; |
76 | |
77 | tree = kmalloc(sizeof(struct audit_tree) + strlen(s) + 1, GFP_KERNEL); |
78 | if (tree) { |
79 | atomic_set(&tree->count, 1); |
80 | tree->goner = 0; |
81 | INIT_LIST_HEAD(&tree->chunks); |
82 | INIT_LIST_HEAD(&tree->rules); |
83 | INIT_LIST_HEAD(&tree->list); |
84 | INIT_LIST_HEAD(&tree->same_root); |
85 | tree->root = NULL; |
86 | strcpy(tree->pathname, s); |
87 | } |
88 | return tree; |
89 | } |
90 | |
91 | static inline void get_tree(struct audit_tree *tree) |
92 | { |
93 | atomic_inc(&tree->count); |
94 | } |
95 | |
96 | static void __put_tree(struct rcu_head *rcu) |
97 | { |
98 | struct audit_tree *tree = container_of(rcu, struct audit_tree, head); |
99 | kfree(tree); |
100 | } |
101 | |
102 | static inline void put_tree(struct audit_tree *tree) |
103 | { |
104 | if (atomic_dec_and_test(&tree->count)) |
105 | call_rcu(&tree->head, __put_tree); |
106 | } |
107 | |
108 | /* to avoid bringing the entire thing in audit.h */ |
109 | const char *audit_tree_path(struct audit_tree *tree) |
110 | { |
111 | return tree->pathname; |
112 | } |
113 | |
114 | static void free_chunk(struct audit_chunk *chunk) |
115 | { |
116 | int i; |
117 | |
118 | for (i = 0; i < chunk->count; i++) { |
119 | if (chunk->owners[i].owner) |
120 | put_tree(chunk->owners[i].owner); |
121 | } |
122 | kfree(chunk); |
123 | } |
124 | |
125 | void audit_put_chunk(struct audit_chunk *chunk) |
126 | { |
127 | if (atomic_long_dec_and_test(&chunk->refs)) |
128 | free_chunk(chunk); |
129 | } |
130 | |
131 | static void __put_chunk(struct rcu_head *rcu) |
132 | { |
133 | struct audit_chunk *chunk = container_of(rcu, struct audit_chunk, head); |
134 | audit_put_chunk(chunk); |
135 | } |
136 | |
137 | static void audit_tree_destroy_watch(struct fsnotify_mark *entry) |
138 | { |
139 | struct audit_chunk *chunk = container_of(entry, struct audit_chunk, mark); |
140 | call_rcu(&chunk->head, __put_chunk); |
141 | } |
142 | |
143 | static struct audit_chunk *alloc_chunk(int count) |
144 | { |
145 | struct audit_chunk *chunk; |
146 | size_t size; |
147 | int i; |
148 | |
149 | size = offsetof(struct audit_chunk, owners) + count * sizeof(struct node); |
150 | chunk = kzalloc(size, GFP_KERNEL); |
151 | if (!chunk) |
152 | return NULL; |
153 | |
154 | INIT_LIST_HEAD(&chunk->hash); |
155 | INIT_LIST_HEAD(&chunk->trees); |
156 | chunk->count = count; |
157 | atomic_long_set(&chunk->refs, 1); |
158 | for (i = 0; i < count; i++) { |
159 | INIT_LIST_HEAD(&chunk->owners[i].list); |
160 | chunk->owners[i].index = i; |
161 | } |
162 | fsnotify_init_mark(&chunk->mark, audit_tree_destroy_watch); |
163 | return chunk; |
164 | } |
165 | |
166 | enum {HASH_SIZE = 128}; |
167 | static struct list_head chunk_hash_heads[HASH_SIZE]; |
168 | static __cacheline_aligned_in_smp DEFINE_SPINLOCK(hash_lock); |
169 | |
170 | static inline struct list_head *chunk_hash(const struct inode *inode) |
171 | { |
172 | unsigned long n = (unsigned long)inode / L1_CACHE_BYTES; |
173 | return chunk_hash_heads + n % HASH_SIZE; |
174 | } |
175 | |
176 | /* hash_lock & entry->lock is held by caller */ |
177 | static void insert_hash(struct audit_chunk *chunk) |
178 | { |
179 | struct fsnotify_mark *entry = &chunk->mark; |
180 | struct list_head *list; |
181 | |
182 | if (!entry->i.inode) |
183 | return; |
184 | list = chunk_hash(entry->i.inode); |
185 | list_add_rcu(&chunk->hash, list); |
186 | } |
187 | |
188 | /* called under rcu_read_lock */ |
189 | struct audit_chunk *audit_tree_lookup(const struct inode *inode) |
190 | { |
191 | struct list_head *list = chunk_hash(inode); |
192 | struct audit_chunk *p; |
193 | |
194 | list_for_each_entry_rcu(p, list, hash) { |
195 | /* mark.inode may have gone NULL, but who cares? */ |
196 | if (p->mark.i.inode == inode) { |
197 | atomic_long_inc(&p->refs); |
198 | return p; |
199 | } |
200 | } |
201 | return NULL; |
202 | } |
203 | |
204 | int audit_tree_match(struct audit_chunk *chunk, struct audit_tree *tree) |
205 | { |
206 | int n; |
207 | for (n = 0; n < chunk->count; n++) |
208 | if (chunk->owners[n].owner == tree) |
209 | return 1; |
210 | return 0; |
211 | } |
212 | |
213 | /* tagging and untagging inodes with trees */ |
214 | |
215 | static struct audit_chunk *find_chunk(struct node *p) |
216 | { |
217 | int index = p->index & ~(1U<<31); |
218 | p -= index; |
219 | return container_of(p, struct audit_chunk, owners[0]); |
220 | } |
221 | |
222 | static void untag_chunk(struct node *p) |
223 | { |
224 | struct audit_chunk *chunk = find_chunk(p); |
225 | struct fsnotify_mark *entry = &chunk->mark; |
226 | struct audit_chunk *new = NULL; |
227 | struct audit_tree *owner; |
228 | int size = chunk->count - 1; |
229 | int i, j; |
230 | |
231 | fsnotify_get_mark(entry); |
232 | |
233 | spin_unlock(&hash_lock); |
234 | |
235 | if (size) |
236 | new = alloc_chunk(size); |
237 | |
238 | spin_lock(&entry->lock); |
239 | if (chunk->dead || !entry->i.inode) { |
240 | spin_unlock(&entry->lock); |
241 | if (new) |
242 | free_chunk(new); |
243 | goto out; |
244 | } |
245 | |
246 | owner = p->owner; |
247 | |
248 | if (!size) { |
249 | chunk->dead = 1; |
250 | spin_lock(&hash_lock); |
251 | list_del_init(&chunk->trees); |
252 | if (owner->root == chunk) |
253 | owner->root = NULL; |
254 | list_del_init(&p->list); |
255 | list_del_rcu(&chunk->hash); |
256 | spin_unlock(&hash_lock); |
257 | spin_unlock(&entry->lock); |
258 | fsnotify_destroy_mark(entry); |
259 | fsnotify_put_mark(entry); |
260 | goto out; |
261 | } |
262 | |
263 | if (!new) |
264 | goto Fallback; |
265 | |
266 | fsnotify_duplicate_mark(&new->mark, entry); |
267 | if (fsnotify_add_mark(&new->mark, new->mark.group, new->mark.i.inode, NULL, 1)) { |
268 | free_chunk(new); |
269 | goto Fallback; |
270 | } |
271 | |
272 | chunk->dead = 1; |
273 | spin_lock(&hash_lock); |
274 | list_replace_init(&chunk->trees, &new->trees); |
275 | if (owner->root == chunk) { |
276 | list_del_init(&owner->same_root); |
277 | owner->root = NULL; |
278 | } |
279 | |
280 | for (i = j = 0; j <= size; i++, j++) { |
281 | struct audit_tree *s; |
282 | if (&chunk->owners[j] == p) { |
283 | list_del_init(&p->list); |
284 | i--; |
285 | continue; |
286 | } |
287 | s = chunk->owners[j].owner; |
288 | new->owners[i].owner = s; |
289 | new->owners[i].index = chunk->owners[j].index - j + i; |
290 | if (!s) /* result of earlier fallback */ |
291 | continue; |
292 | get_tree(s); |
293 | list_replace_init(&chunk->owners[j].list, &new->owners[i].list); |
294 | } |
295 | |
296 | list_replace_rcu(&chunk->hash, &new->hash); |
297 | list_for_each_entry(owner, &new->trees, same_root) |
298 | owner->root = new; |
299 | spin_unlock(&hash_lock); |
300 | spin_unlock(&entry->lock); |
301 | fsnotify_destroy_mark(entry); |
302 | fsnotify_put_mark(entry); |
303 | goto out; |
304 | |
305 | Fallback: |
306 | // do the best we can |
307 | spin_lock(&hash_lock); |
308 | if (owner->root == chunk) { |
309 | list_del_init(&owner->same_root); |
310 | owner->root = NULL; |
311 | } |
312 | list_del_init(&p->list); |
313 | p->owner = NULL; |
314 | put_tree(owner); |
315 | spin_unlock(&hash_lock); |
316 | spin_unlock(&entry->lock); |
317 | out: |
318 | fsnotify_put_mark(entry); |
319 | spin_lock(&hash_lock); |
320 | } |
321 | |
322 | static int create_chunk(struct inode *inode, struct audit_tree *tree) |
323 | { |
324 | struct fsnotify_mark *entry; |
325 | struct audit_chunk *chunk = alloc_chunk(1); |
326 | if (!chunk) |
327 | return -ENOMEM; |
328 | |
329 | entry = &chunk->mark; |
330 | if (fsnotify_add_mark(entry, audit_tree_group, inode, NULL, 0)) { |
331 | free_chunk(chunk); |
332 | return -ENOSPC; |
333 | } |
334 | |
335 | spin_lock(&entry->lock); |
336 | spin_lock(&hash_lock); |
337 | if (tree->goner) { |
338 | spin_unlock(&hash_lock); |
339 | chunk->dead = 1; |
340 | spin_unlock(&entry->lock); |
341 | fsnotify_destroy_mark(entry); |
342 | fsnotify_put_mark(entry); |
343 | return 0; |
344 | } |
345 | chunk->owners[0].index = (1U << 31); |
346 | chunk->owners[0].owner = tree; |
347 | get_tree(tree); |
348 | list_add(&chunk->owners[0].list, &tree->chunks); |
349 | if (!tree->root) { |
350 | tree->root = chunk; |
351 | list_add(&tree->same_root, &chunk->trees); |
352 | } |
353 | insert_hash(chunk); |
354 | spin_unlock(&hash_lock); |
355 | spin_unlock(&entry->lock); |
356 | return 0; |
357 | } |
358 | |
359 | /* the first tagged inode becomes root of tree */ |
360 | static int tag_chunk(struct inode *inode, struct audit_tree *tree) |
361 | { |
362 | struct fsnotify_mark *old_entry, *chunk_entry; |
363 | struct audit_tree *owner; |
364 | struct audit_chunk *chunk, *old; |
365 | struct node *p; |
366 | int n; |
367 | |
368 | old_entry = fsnotify_find_inode_mark(audit_tree_group, inode); |
369 | if (!old_entry) |
370 | return create_chunk(inode, tree); |
371 | |
372 | old = container_of(old_entry, struct audit_chunk, mark); |
373 | |
374 | /* are we already there? */ |
375 | spin_lock(&hash_lock); |
376 | for (n = 0; n < old->count; n++) { |
377 | if (old->owners[n].owner == tree) { |
378 | spin_unlock(&hash_lock); |
379 | fsnotify_put_mark(old_entry); |
380 | return 0; |
381 | } |
382 | } |
383 | spin_unlock(&hash_lock); |
384 | |
385 | chunk = alloc_chunk(old->count + 1); |
386 | if (!chunk) { |
387 | fsnotify_put_mark(old_entry); |
388 | return -ENOMEM; |
389 | } |
390 | |
391 | chunk_entry = &chunk->mark; |
392 | |
393 | spin_lock(&old_entry->lock); |
394 | if (!old_entry->i.inode) { |
395 | /* old_entry is being shot, lets just lie */ |
396 | spin_unlock(&old_entry->lock); |
397 | fsnotify_put_mark(old_entry); |
398 | free_chunk(chunk); |
399 | return -ENOENT; |
400 | } |
401 | |
402 | fsnotify_duplicate_mark(chunk_entry, old_entry); |
403 | if (fsnotify_add_mark(chunk_entry, chunk_entry->group, chunk_entry->i.inode, NULL, 1)) { |
404 | spin_unlock(&old_entry->lock); |
405 | free_chunk(chunk); |
406 | fsnotify_put_mark(old_entry); |
407 | return -ENOSPC; |
408 | } |
409 | |
410 | /* even though we hold old_entry->lock, this is safe since chunk_entry->lock could NEVER have been grabbed before */ |
411 | spin_lock(&chunk_entry->lock); |
412 | spin_lock(&hash_lock); |
413 | |
414 | /* we now hold old_entry->lock, chunk_entry->lock, and hash_lock */ |
415 | if (tree->goner) { |
416 | spin_unlock(&hash_lock); |
417 | chunk->dead = 1; |
418 | spin_unlock(&chunk_entry->lock); |
419 | spin_unlock(&old_entry->lock); |
420 | |
421 | fsnotify_destroy_mark(chunk_entry); |
422 | |
423 | fsnotify_put_mark(chunk_entry); |
424 | fsnotify_put_mark(old_entry); |
425 | return 0; |
426 | } |
427 | list_replace_init(&old->trees, &chunk->trees); |
428 | for (n = 0, p = chunk->owners; n < old->count; n++, p++) { |
429 | struct audit_tree *s = old->owners[n].owner; |
430 | p->owner = s; |
431 | p->index = old->owners[n].index; |
432 | if (!s) /* result of fallback in untag */ |
433 | continue; |
434 | get_tree(s); |
435 | list_replace_init(&old->owners[n].list, &p->list); |
436 | } |
437 | p->index = (chunk->count - 1) | (1U<<31); |
438 | p->owner = tree; |
439 | get_tree(tree); |
440 | list_add(&p->list, &tree->chunks); |
441 | list_replace_rcu(&old->hash, &chunk->hash); |
442 | list_for_each_entry(owner, &chunk->trees, same_root) |
443 | owner->root = chunk; |
444 | old->dead = 1; |
445 | if (!tree->root) { |
446 | tree->root = chunk; |
447 | list_add(&tree->same_root, &chunk->trees); |
448 | } |
449 | spin_unlock(&hash_lock); |
450 | spin_unlock(&chunk_entry->lock); |
451 | spin_unlock(&old_entry->lock); |
452 | fsnotify_destroy_mark(old_entry); |
453 | fsnotify_put_mark(old_entry); /* pair to fsnotify_find mark_entry */ |
454 | fsnotify_put_mark(old_entry); /* and kill it */ |
455 | return 0; |
456 | } |
457 | |
458 | static void kill_rules(struct audit_tree *tree) |
459 | { |
460 | struct audit_krule *rule, *next; |
461 | struct audit_entry *entry; |
462 | struct audit_buffer *ab; |
463 | |
464 | list_for_each_entry_safe(rule, next, &tree->rules, rlist) { |
465 | entry = container_of(rule, struct audit_entry, rule); |
466 | |
467 | list_del_init(&rule->rlist); |
468 | if (rule->tree) { |
469 | /* not a half-baked one */ |
470 | ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE); |
471 | audit_log_format(ab, "op="); |
472 | audit_log_string(ab, "remove rule"); |
473 | audit_log_format(ab, " dir="); |
474 | audit_log_untrustedstring(ab, rule->tree->pathname); |
475 | audit_log_key(ab, rule->filterkey); |
476 | audit_log_format(ab, " list=%d res=1", rule->listnr); |
477 | audit_log_end(ab); |
478 | rule->tree = NULL; |
479 | list_del_rcu(&entry->list); |
480 | list_del(&entry->rule.list); |
481 | call_rcu(&entry->rcu, audit_free_rule_rcu); |
482 | } |
483 | } |
484 | } |
485 | |
486 | /* |
487 | * finish killing struct audit_tree |
488 | */ |
489 | static void prune_one(struct audit_tree *victim) |
490 | { |
491 | spin_lock(&hash_lock); |
492 | while (!list_empty(&victim->chunks)) { |
493 | struct node *p; |
494 | |
495 | p = list_entry(victim->chunks.next, struct node, list); |
496 | |
497 | untag_chunk(p); |
498 | } |
499 | spin_unlock(&hash_lock); |
500 | put_tree(victim); |
501 | } |
502 | |
503 | /* trim the uncommitted chunks from tree */ |
504 | |
505 | static void trim_marked(struct audit_tree *tree) |
506 | { |
507 | struct list_head *p, *q; |
508 | spin_lock(&hash_lock); |
509 | if (tree->goner) { |
510 | spin_unlock(&hash_lock); |
511 | return; |
512 | } |
513 | /* reorder */ |
514 | for (p = tree->chunks.next; p != &tree->chunks; p = q) { |
515 | struct node *node = list_entry(p, struct node, list); |
516 | q = p->next; |
517 | if (node->index & (1U<<31)) { |
518 | list_del_init(p); |
519 | list_add(p, &tree->chunks); |
520 | } |
521 | } |
522 | |
523 | while (!list_empty(&tree->chunks)) { |
524 | struct node *node; |
525 | |
526 | node = list_entry(tree->chunks.next, struct node, list); |
527 | |
528 | /* have we run out of marked? */ |
529 | if (!(node->index & (1U<<31))) |
530 | break; |
531 | |
532 | untag_chunk(node); |
533 | } |
534 | if (!tree->root && !tree->goner) { |
535 | tree->goner = 1; |
536 | spin_unlock(&hash_lock); |
537 | mutex_lock(&audit_filter_mutex); |
538 | kill_rules(tree); |
539 | list_del_init(&tree->list); |
540 | mutex_unlock(&audit_filter_mutex); |
541 | prune_one(tree); |
542 | } else { |
543 | spin_unlock(&hash_lock); |
544 | } |
545 | } |
546 | |
547 | static void audit_schedule_prune(void); |
548 | |
549 | /* called with audit_filter_mutex */ |
550 | int audit_remove_tree_rule(struct audit_krule *rule) |
551 | { |
552 | struct audit_tree *tree; |
553 | tree = rule->tree; |
554 | if (tree) { |
555 | spin_lock(&hash_lock); |
556 | list_del_init(&rule->rlist); |
557 | if (list_empty(&tree->rules) && !tree->goner) { |
558 | tree->root = NULL; |
559 | list_del_init(&tree->same_root); |
560 | tree->goner = 1; |
561 | list_move(&tree->list, &prune_list); |
562 | rule->tree = NULL; |
563 | spin_unlock(&hash_lock); |
564 | audit_schedule_prune(); |
565 | return 1; |
566 | } |
567 | rule->tree = NULL; |
568 | spin_unlock(&hash_lock); |
569 | return 1; |
570 | } |
571 | return 0; |
572 | } |
573 | |
574 | static int compare_root(struct vfsmount *mnt, void *arg) |
575 | { |
576 | return mnt->mnt_root->d_inode == arg; |
577 | } |
578 | |
579 | void audit_trim_trees(void) |
580 | { |
581 | struct list_head cursor; |
582 | |
583 | mutex_lock(&audit_filter_mutex); |
584 | list_add(&cursor, &tree_list); |
585 | while (cursor.next != &tree_list) { |
586 | struct audit_tree *tree; |
587 | struct path path; |
588 | struct vfsmount *root_mnt; |
589 | struct node *node; |
590 | int err; |
591 | |
592 | tree = container_of(cursor.next, struct audit_tree, list); |
593 | get_tree(tree); |
594 | list_del(&cursor); |
595 | list_add(&cursor, &tree->list); |
596 | mutex_unlock(&audit_filter_mutex); |
597 | |
598 | err = kern_path(tree->pathname, 0, &path); |
599 | if (err) |
600 | goto skip_it; |
601 | |
602 | root_mnt = collect_mounts(&path); |
603 | path_put(&path); |
604 | if (!root_mnt) |
605 | goto skip_it; |
606 | |
607 | spin_lock(&hash_lock); |
608 | list_for_each_entry(node, &tree->chunks, list) { |
609 | struct audit_chunk *chunk = find_chunk(node); |
610 | /* this could be NULL if the watch is dieing else where... */ |
611 | struct inode *inode = chunk->mark.i.inode; |
612 | node->index |= 1U<<31; |
613 | if (iterate_mounts(compare_root, inode, root_mnt)) |
614 | node->index &= ~(1U<<31); |
615 | } |
616 | spin_unlock(&hash_lock); |
617 | trim_marked(tree); |
618 | put_tree(tree); |
619 | drop_collected_mounts(root_mnt); |
620 | skip_it: |
621 | mutex_lock(&audit_filter_mutex); |
622 | } |
623 | list_del(&cursor); |
624 | mutex_unlock(&audit_filter_mutex); |
625 | } |
626 | |
627 | int audit_make_tree(struct audit_krule *rule, char *pathname, u32 op) |
628 | { |
629 | |
630 | if (pathname[0] != '/' || |
631 | rule->listnr != AUDIT_FILTER_EXIT || |
632 | op != Audit_equal || |
633 | rule->inode_f || rule->watch || rule->tree) |
634 | return -EINVAL; |
635 | rule->tree = alloc_tree(pathname); |
636 | if (!rule->tree) |
637 | return -ENOMEM; |
638 | return 0; |
639 | } |
640 | |
641 | void audit_put_tree(struct audit_tree *tree) |
642 | { |
643 | put_tree(tree); |
644 | } |
645 | |
646 | static int tag_mount(struct vfsmount *mnt, void *arg) |
647 | { |
648 | return tag_chunk(mnt->mnt_root->d_inode, arg); |
649 | } |
650 | |
651 | /* called with audit_filter_mutex */ |
652 | int audit_add_tree_rule(struct audit_krule *rule) |
653 | { |
654 | struct audit_tree *seed = rule->tree, *tree; |
655 | struct path path; |
656 | struct vfsmount *mnt; |
657 | int err; |
658 | |
659 | list_for_each_entry(tree, &tree_list, list) { |
660 | if (!strcmp(seed->pathname, tree->pathname)) { |
661 | put_tree(seed); |
662 | rule->tree = tree; |
663 | list_add(&rule->rlist, &tree->rules); |
664 | return 0; |
665 | } |
666 | } |
667 | tree = seed; |
668 | list_add(&tree->list, &tree_list); |
669 | list_add(&rule->rlist, &tree->rules); |
670 | /* do not set rule->tree yet */ |
671 | mutex_unlock(&audit_filter_mutex); |
672 | |
673 | err = kern_path(tree->pathname, 0, &path); |
674 | if (err) |
675 | goto Err; |
676 | mnt = collect_mounts(&path); |
677 | path_put(&path); |
678 | if (!mnt) { |
679 | err = -ENOMEM; |
680 | goto Err; |
681 | } |
682 | |
683 | get_tree(tree); |
684 | err = iterate_mounts(tag_mount, tree, mnt); |
685 | drop_collected_mounts(mnt); |
686 | |
687 | if (!err) { |
688 | struct node *node; |
689 | spin_lock(&hash_lock); |
690 | list_for_each_entry(node, &tree->chunks, list) |
691 | node->index &= ~(1U<<31); |
692 | spin_unlock(&hash_lock); |
693 | } else { |
694 | trim_marked(tree); |
695 | goto Err; |
696 | } |
697 | |
698 | mutex_lock(&audit_filter_mutex); |
699 | if (list_empty(&rule->rlist)) { |
700 | put_tree(tree); |
701 | return -ENOENT; |
702 | } |
703 | rule->tree = tree; |
704 | put_tree(tree); |
705 | |
706 | return 0; |
707 | Err: |
708 | mutex_lock(&audit_filter_mutex); |
709 | list_del_init(&tree->list); |
710 | list_del_init(&tree->rules); |
711 | put_tree(tree); |
712 | return err; |
713 | } |
714 | |
715 | int audit_tag_tree(char *old, char *new) |
716 | { |
717 | struct list_head cursor, barrier; |
718 | int failed = 0; |
719 | struct path path1, path2; |
720 | struct vfsmount *tagged; |
721 | int err; |
722 | |
723 | err = kern_path(new, 0, &path2); |
724 | if (err) |
725 | return err; |
726 | tagged = collect_mounts(&path2); |
727 | path_put(&path2); |
728 | if (!tagged) |
729 | return -ENOMEM; |
730 | |
731 | err = kern_path(old, 0, &path1); |
732 | if (err) { |
733 | drop_collected_mounts(tagged); |
734 | return err; |
735 | } |
736 | |
737 | mutex_lock(&audit_filter_mutex); |
738 | list_add(&barrier, &tree_list); |
739 | list_add(&cursor, &barrier); |
740 | |
741 | while (cursor.next != &tree_list) { |
742 | struct audit_tree *tree; |
743 | int good_one = 0; |
744 | |
745 | tree = container_of(cursor.next, struct audit_tree, list); |
746 | get_tree(tree); |
747 | list_del(&cursor); |
748 | list_add(&cursor, &tree->list); |
749 | mutex_unlock(&audit_filter_mutex); |
750 | |
751 | err = kern_path(tree->pathname, 0, &path2); |
752 | if (!err) { |
753 | good_one = path_is_under(&path1, &path2); |
754 | path_put(&path2); |
755 | } |
756 | |
757 | if (!good_one) { |
758 | put_tree(tree); |
759 | mutex_lock(&audit_filter_mutex); |
760 | continue; |
761 | } |
762 | |
763 | failed = iterate_mounts(tag_mount, tree, tagged); |
764 | if (failed) { |
765 | put_tree(tree); |
766 | mutex_lock(&audit_filter_mutex); |
767 | break; |
768 | } |
769 | |
770 | mutex_lock(&audit_filter_mutex); |
771 | spin_lock(&hash_lock); |
772 | if (!tree->goner) { |
773 | list_del(&tree->list); |
774 | list_add(&tree->list, &tree_list); |
775 | } |
776 | spin_unlock(&hash_lock); |
777 | put_tree(tree); |
778 | } |
779 | |
780 | while (barrier.prev != &tree_list) { |
781 | struct audit_tree *tree; |
782 | |
783 | tree = container_of(barrier.prev, struct audit_tree, list); |
784 | get_tree(tree); |
785 | list_del(&tree->list); |
786 | list_add(&tree->list, &barrier); |
787 | mutex_unlock(&audit_filter_mutex); |
788 | |
789 | if (!failed) { |
790 | struct node *node; |
791 | spin_lock(&hash_lock); |
792 | list_for_each_entry(node, &tree->chunks, list) |
793 | node->index &= ~(1U<<31); |
794 | spin_unlock(&hash_lock); |
795 | } else { |
796 | trim_marked(tree); |
797 | } |
798 | |
799 | put_tree(tree); |
800 | mutex_lock(&audit_filter_mutex); |
801 | } |
802 | list_del(&barrier); |
803 | list_del(&cursor); |
804 | mutex_unlock(&audit_filter_mutex); |
805 | path_put(&path1); |
806 | drop_collected_mounts(tagged); |
807 | return failed; |
808 | } |
809 | |
810 | /* |
811 | * That gets run when evict_chunk() ends up needing to kill audit_tree. |
812 | * Runs from a separate thread. |
813 | */ |
814 | static int prune_tree_thread(void *unused) |
815 | { |
816 | mutex_lock(&audit_cmd_mutex); |
817 | mutex_lock(&audit_filter_mutex); |
818 | |
819 | while (!list_empty(&prune_list)) { |
820 | struct audit_tree *victim; |
821 | |
822 | victim = list_entry(prune_list.next, struct audit_tree, list); |
823 | list_del_init(&victim->list); |
824 | |
825 | mutex_unlock(&audit_filter_mutex); |
826 | |
827 | prune_one(victim); |
828 | |
829 | mutex_lock(&audit_filter_mutex); |
830 | } |
831 | |
832 | mutex_unlock(&audit_filter_mutex); |
833 | mutex_unlock(&audit_cmd_mutex); |
834 | return 0; |
835 | } |
836 | |
837 | static void audit_schedule_prune(void) |
838 | { |
839 | kthread_run(prune_tree_thread, NULL, "audit_prune_tree"); |
840 | } |
841 | |
842 | /* |
843 | * ... and that one is done if evict_chunk() decides to delay until the end |
844 | * of syscall. Runs synchronously. |
845 | */ |
846 | void audit_kill_trees(struct list_head *list) |
847 | { |
848 | mutex_lock(&audit_cmd_mutex); |
849 | mutex_lock(&audit_filter_mutex); |
850 | |
851 | while (!list_empty(list)) { |
852 | struct audit_tree *victim; |
853 | |
854 | victim = list_entry(list->next, struct audit_tree, list); |
855 | kill_rules(victim); |
856 | list_del_init(&victim->list); |
857 | |
858 | mutex_unlock(&audit_filter_mutex); |
859 | |
860 | prune_one(victim); |
861 | |
862 | mutex_lock(&audit_filter_mutex); |
863 | } |
864 | |
865 | mutex_unlock(&audit_filter_mutex); |
866 | mutex_unlock(&audit_cmd_mutex); |
867 | } |
868 | |
869 | /* |
870 | * Here comes the stuff asynchronous to auditctl operations |
871 | */ |
872 | |
873 | static void evict_chunk(struct audit_chunk *chunk) |
874 | { |
875 | struct audit_tree *owner; |
876 | struct list_head *postponed = audit_killed_trees(); |
877 | int need_prune = 0; |
878 | int n; |
879 | |
880 | if (chunk->dead) |
881 | return; |
882 | |
883 | chunk->dead = 1; |
884 | mutex_lock(&audit_filter_mutex); |
885 | spin_lock(&hash_lock); |
886 | while (!list_empty(&chunk->trees)) { |
887 | owner = list_entry(chunk->trees.next, |
888 | struct audit_tree, same_root); |
889 | owner->goner = 1; |
890 | owner->root = NULL; |
891 | list_del_init(&owner->same_root); |
892 | spin_unlock(&hash_lock); |
893 | if (!postponed) { |
894 | kill_rules(owner); |
895 | list_move(&owner->list, &prune_list); |
896 | need_prune = 1; |
897 | } else { |
898 | list_move(&owner->list, postponed); |
899 | } |
900 | spin_lock(&hash_lock); |
901 | } |
902 | list_del_rcu(&chunk->hash); |
903 | for (n = 0; n < chunk->count; n++) |
904 | list_del_init(&chunk->owners[n].list); |
905 | spin_unlock(&hash_lock); |
906 | if (need_prune) |
907 | audit_schedule_prune(); |
908 | mutex_unlock(&audit_filter_mutex); |
909 | } |
910 | |
911 | static int audit_tree_handle_event(struct fsnotify_group *group, |
912 | struct fsnotify_mark *inode_mark, |
913 | struct fsnotify_mark *vfsmonut_mark, |
914 | struct fsnotify_event *event) |
915 | { |
916 | BUG(); |
917 | return -EOPNOTSUPP; |
918 | } |
919 | |
920 | static void audit_tree_freeing_mark(struct fsnotify_mark *entry, struct fsnotify_group *group) |
921 | { |
922 | struct audit_chunk *chunk = container_of(entry, struct audit_chunk, mark); |
923 | |
924 | evict_chunk(chunk); |
925 | fsnotify_put_mark(entry); |
926 | } |
927 | |
928 | static bool audit_tree_send_event(struct fsnotify_group *group, struct inode *inode, |
929 | struct fsnotify_mark *inode_mark, |
930 | struct fsnotify_mark *vfsmount_mark, |
931 | __u32 mask, void *data, int data_type) |
932 | { |
933 | return false; |
934 | } |
935 | |
936 | static const struct fsnotify_ops audit_tree_ops = { |
937 | .handle_event = audit_tree_handle_event, |
938 | .should_send_event = audit_tree_send_event, |
939 | .free_group_priv = NULL, |
940 | .free_event_priv = NULL, |
941 | .freeing_mark = audit_tree_freeing_mark, |
942 | }; |
943 | |
944 | static int __init audit_tree_init(void) |
945 | { |
946 | int i; |
947 | |
948 | audit_tree_group = fsnotify_alloc_group(&audit_tree_ops); |
949 | if (IS_ERR(audit_tree_group)) |
950 | audit_panic("cannot initialize fsnotify group for rectree watches"); |
951 | |
952 | for (i = 0; i < HASH_SIZE; i++) |
953 | INIT_LIST_HEAD(&chunk_hash_heads[i]); |
954 | |
955 | return 0; |
956 | } |
957 | __initcall(audit_tree_init); |
958 |
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
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v3.9