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Commit | Line | Data |
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74c3cbe3 | 1 | #include "audit.h" |
28a3a7eb | 2 | #include <linux/fsnotify_backend.h> |
74c3cbe3 AV |
3 | #include <linux/namei.h> |
4 | #include <linux/mount.h> | |
916d7576 | 5 | #include <linux/kthread.h> |
5a0e3ad6 | 6 | #include <linux/slab.h> |
74c3cbe3 AV |
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; | |
28a3a7eb | 25 | struct fsnotify_mark_entry mark; |
74c3cbe3 AV |
26 | struct list_head trees; /* with root here */ |
27 | int dead; | |
28 | int count; | |
8f7b0ba1 | 29 | atomic_long_t refs; |
74c3cbe3 AV |
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 | * | |
28a3a7eb | 62 | * chunk is refcounted by embedded fsnotify_mark + .refs (non-zero refcount |
8f7b0ba1 | 63 | * of watch contributes 1 to .refs). |
74c3cbe3 AV |
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 | ||
28a3a7eb | 71 | static struct fsnotify_group *audit_tree_group; |
74c3cbe3 AV |
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 | ||
8f7b0ba1 | 114 | static void free_chunk(struct audit_chunk *chunk) |
74c3cbe3 | 115 | { |
74c3cbe3 AV |
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 | ||
8f7b0ba1 | 125 | void audit_put_chunk(struct audit_chunk *chunk) |
74c3cbe3 | 126 | { |
8f7b0ba1 AV |
127 | if (atomic_long_dec_and_test(&chunk->refs)) |
128 | free_chunk(chunk); | |
74c3cbe3 AV |
129 | } |
130 | ||
8f7b0ba1 | 131 | static void __put_chunk(struct rcu_head *rcu) |
74c3cbe3 | 132 | { |
8f7b0ba1 AV |
133 | struct audit_chunk *chunk = container_of(rcu, struct audit_chunk, head); |
134 | audit_put_chunk(chunk); | |
74c3cbe3 AV |
135 | } |
136 | ||
28a3a7eb EP |
137 | static void audit_tree_destroy_watch(struct fsnotify_mark_entry *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 | ||
74c3cbe3 AV |
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 | ||
28a3a7eb | 176 | /* hash_lock & entry->lock is held by caller */ |
74c3cbe3 AV |
177 | static void insert_hash(struct audit_chunk *chunk) |
178 | { | |
28a3a7eb EP |
179 | struct fsnotify_mark_entry *entry = &chunk->mark; |
180 | struct list_head *list; | |
181 | ||
182 | if (!entry->inode) | |
183 | return; | |
184 | list = chunk_hash(entry->inode); | |
74c3cbe3 AV |
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); | |
6793a051 | 192 | struct audit_chunk *p; |
74c3cbe3 | 193 | |
6793a051 | 194 | list_for_each_entry_rcu(p, list, hash) { |
28a3a7eb EP |
195 | /* mark.inode may have gone NULL, but who cares? */ |
196 | if (p->mark.inode == inode) { | |
8f7b0ba1 | 197 | atomic_long_inc(&p->refs); |
74c3cbe3 AV |
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 | ||
8f7b0ba1 AV |
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) | |
74c3cbe3 | 223 | { |
8f7b0ba1 | 224 | struct audit_chunk *chunk = find_chunk(p); |
28a3a7eb | 225 | struct fsnotify_mark_entry *entry = &chunk->mark; |
74c3cbe3 AV |
226 | struct audit_chunk *new; |
227 | struct audit_tree *owner; | |
228 | int size = chunk->count - 1; | |
229 | int i, j; | |
230 | ||
28a3a7eb | 231 | fsnotify_get_mark(entry); |
8f7b0ba1 AV |
232 | |
233 | spin_unlock(&hash_lock); | |
234 | ||
28a3a7eb EP |
235 | spin_lock(&entry->lock); |
236 | if (chunk->dead || !entry->inode) { | |
237 | spin_unlock(&entry->lock); | |
8f7b0ba1 | 238 | goto out; |
74c3cbe3 AV |
239 | } |
240 | ||
241 | owner = p->owner; | |
242 | ||
243 | if (!size) { | |
244 | chunk->dead = 1; | |
245 | spin_lock(&hash_lock); | |
246 | list_del_init(&chunk->trees); | |
247 | if (owner->root == chunk) | |
248 | owner->root = NULL; | |
249 | list_del_init(&p->list); | |
250 | list_del_rcu(&chunk->hash); | |
251 | spin_unlock(&hash_lock); | |
28a3a7eb EP |
252 | spin_unlock(&entry->lock); |
253 | fsnotify_destroy_mark_by_entry(entry); | |
254 | fsnotify_put_mark(entry); | |
8f7b0ba1 | 255 | goto out; |
74c3cbe3 AV |
256 | } |
257 | ||
258 | new = alloc_chunk(size); | |
259 | if (!new) | |
260 | goto Fallback; | |
28a3a7eb EP |
261 | fsnotify_duplicate_mark(&new->mark, entry); |
262 | if (fsnotify_add_mark(&new->mark, new->mark.group, new->mark.inode, 1)) { | |
74c3cbe3 AV |
263 | free_chunk(new); |
264 | goto Fallback; | |
265 | } | |
266 | ||
267 | chunk->dead = 1; | |
268 | spin_lock(&hash_lock); | |
269 | list_replace_init(&chunk->trees, &new->trees); | |
270 | if (owner->root == chunk) { | |
271 | list_del_init(&owner->same_root); | |
272 | owner->root = NULL; | |
273 | } | |
274 | ||
6f5d5114 | 275 | for (i = j = 0; j <= size; i++, j++) { |
74c3cbe3 AV |
276 | struct audit_tree *s; |
277 | if (&chunk->owners[j] == p) { | |
278 | list_del_init(&p->list); | |
279 | i--; | |
280 | continue; | |
281 | } | |
282 | s = chunk->owners[j].owner; | |
283 | new->owners[i].owner = s; | |
284 | new->owners[i].index = chunk->owners[j].index - j + i; | |
285 | if (!s) /* result of earlier fallback */ | |
286 | continue; | |
287 | get_tree(s); | |
6f5d5114 | 288 | list_replace_init(&chunk->owners[j].list, &new->owners[i].list); |
74c3cbe3 AV |
289 | } |
290 | ||
291 | list_replace_rcu(&chunk->hash, &new->hash); | |
292 | list_for_each_entry(owner, &new->trees, same_root) | |
293 | owner->root = new; | |
294 | spin_unlock(&hash_lock); | |
28a3a7eb EP |
295 | spin_unlock(&entry->lock); |
296 | fsnotify_destroy_mark_by_entry(entry); | |
297 | fsnotify_put_mark(entry); | |
8f7b0ba1 | 298 | goto out; |
74c3cbe3 AV |
299 | |
300 | Fallback: | |
301 | // do the best we can | |
302 | spin_lock(&hash_lock); | |
303 | if (owner->root == chunk) { | |
304 | list_del_init(&owner->same_root); | |
305 | owner->root = NULL; | |
306 | } | |
307 | list_del_init(&p->list); | |
308 | p->owner = NULL; | |
309 | put_tree(owner); | |
310 | spin_unlock(&hash_lock); | |
28a3a7eb | 311 | spin_unlock(&entry->lock); |
8f7b0ba1 | 312 | out: |
28a3a7eb | 313 | fsnotify_put_mark(entry); |
8f7b0ba1 | 314 | spin_lock(&hash_lock); |
74c3cbe3 AV |
315 | } |
316 | ||
317 | static int create_chunk(struct inode *inode, struct audit_tree *tree) | |
318 | { | |
28a3a7eb | 319 | struct fsnotify_mark_entry *entry; |
74c3cbe3 AV |
320 | struct audit_chunk *chunk = alloc_chunk(1); |
321 | if (!chunk) | |
322 | return -ENOMEM; | |
323 | ||
28a3a7eb EP |
324 | entry = &chunk->mark; |
325 | if (fsnotify_add_mark(entry, audit_tree_group, inode, 0)) { | |
74c3cbe3 AV |
326 | free_chunk(chunk); |
327 | return -ENOSPC; | |
328 | } | |
329 | ||
28a3a7eb | 330 | spin_lock(&entry->lock); |
74c3cbe3 AV |
331 | spin_lock(&hash_lock); |
332 | if (tree->goner) { | |
333 | spin_unlock(&hash_lock); | |
334 | chunk->dead = 1; | |
28a3a7eb EP |
335 | spin_unlock(&entry->lock); |
336 | fsnotify_destroy_mark_by_entry(entry); | |
337 | fsnotify_put_mark(entry); | |
74c3cbe3 AV |
338 | return 0; |
339 | } | |
340 | chunk->owners[0].index = (1U << 31); | |
341 | chunk->owners[0].owner = tree; | |
342 | get_tree(tree); | |
343 | list_add(&chunk->owners[0].list, &tree->chunks); | |
344 | if (!tree->root) { | |
345 | tree->root = chunk; | |
346 | list_add(&tree->same_root, &chunk->trees); | |
347 | } | |
348 | insert_hash(chunk); | |
349 | spin_unlock(&hash_lock); | |
28a3a7eb | 350 | spin_unlock(&entry->lock); |
74c3cbe3 AV |
351 | return 0; |
352 | } | |
353 | ||
354 | /* the first tagged inode becomes root of tree */ | |
355 | static int tag_chunk(struct inode *inode, struct audit_tree *tree) | |
356 | { | |
28a3a7eb | 357 | struct fsnotify_mark_entry *old_entry, *chunk_entry; |
74c3cbe3 AV |
358 | struct audit_tree *owner; |
359 | struct audit_chunk *chunk, *old; | |
360 | struct node *p; | |
361 | int n; | |
362 | ||
28a3a7eb EP |
363 | spin_lock(&inode->i_lock); |
364 | old_entry = fsnotify_find_mark_entry(audit_tree_group, inode); | |
365 | spin_unlock(&inode->i_lock); | |
366 | if (!old_entry) | |
74c3cbe3 AV |
367 | return create_chunk(inode, tree); |
368 | ||
28a3a7eb | 369 | old = container_of(old_entry, struct audit_chunk, mark); |
74c3cbe3 AV |
370 | |
371 | /* are we already there? */ | |
372 | spin_lock(&hash_lock); | |
373 | for (n = 0; n < old->count; n++) { | |
374 | if (old->owners[n].owner == tree) { | |
375 | spin_unlock(&hash_lock); | |
28a3a7eb | 376 | fsnotify_put_mark(old_entry); |
74c3cbe3 AV |
377 | return 0; |
378 | } | |
379 | } | |
380 | spin_unlock(&hash_lock); | |
381 | ||
382 | chunk = alloc_chunk(old->count + 1); | |
b4c30aad | 383 | if (!chunk) { |
28a3a7eb | 384 | fsnotify_put_mark(old_entry); |
74c3cbe3 | 385 | return -ENOMEM; |
b4c30aad | 386 | } |
74c3cbe3 | 387 | |
28a3a7eb EP |
388 | chunk_entry = &chunk->mark; |
389 | ||
390 | spin_lock(&old_entry->lock); | |
391 | if (!old_entry->inode) { | |
392 | /* old_entry is being shot, lets just lie */ | |
393 | spin_unlock(&old_entry->lock); | |
394 | fsnotify_put_mark(old_entry); | |
74c3cbe3 | 395 | free_chunk(chunk); |
28a3a7eb EP |
396 | return -ENOENT; |
397 | } | |
398 | ||
399 | fsnotify_duplicate_mark(chunk_entry, old_entry); | |
400 | if (fsnotify_add_mark(chunk_entry, chunk_entry->group, chunk_entry->inode, 1)) { | |
401 | spin_unlock(&old_entry->lock); | |
402 | free_chunk(chunk); | |
403 | fsnotify_put_mark(old_entry); | |
74c3cbe3 AV |
404 | return -ENOSPC; |
405 | } | |
28a3a7eb EP |
406 | |
407 | /* even though we hold old_entry->lock, this is safe since chunk_entry->lock could NEVER have been grabbed before */ | |
408 | spin_lock(&chunk_entry->lock); | |
74c3cbe3 | 409 | spin_lock(&hash_lock); |
28a3a7eb EP |
410 | |
411 | /* we now hold old_entry->lock, chunk_entry->lock, and hash_lock */ | |
74c3cbe3 AV |
412 | if (tree->goner) { |
413 | spin_unlock(&hash_lock); | |
414 | chunk->dead = 1; | |
28a3a7eb EP |
415 | spin_unlock(&chunk_entry->lock); |
416 | spin_unlock(&old_entry->lock); | |
417 | ||
418 | fsnotify_destroy_mark_by_entry(chunk_entry); | |
419 | ||
420 | fsnotify_put_mark(chunk_entry); | |
421 | fsnotify_put_mark(old_entry); | |
74c3cbe3 AV |
422 | return 0; |
423 | } | |
424 | list_replace_init(&old->trees, &chunk->trees); | |
425 | for (n = 0, p = chunk->owners; n < old->count; n++, p++) { | |
426 | struct audit_tree *s = old->owners[n].owner; | |
427 | p->owner = s; | |
428 | p->index = old->owners[n].index; | |
429 | if (!s) /* result of fallback in untag */ | |
430 | continue; | |
431 | get_tree(s); | |
432 | list_replace_init(&old->owners[n].list, &p->list); | |
433 | } | |
434 | p->index = (chunk->count - 1) | (1U<<31); | |
435 | p->owner = tree; | |
436 | get_tree(tree); | |
437 | list_add(&p->list, &tree->chunks); | |
438 | list_replace_rcu(&old->hash, &chunk->hash); | |
439 | list_for_each_entry(owner, &chunk->trees, same_root) | |
440 | owner->root = chunk; | |
441 | old->dead = 1; | |
442 | if (!tree->root) { | |
443 | tree->root = chunk; | |
444 | list_add(&tree->same_root, &chunk->trees); | |
445 | } | |
446 | spin_unlock(&hash_lock); | |
28a3a7eb EP |
447 | spin_unlock(&chunk_entry->lock); |
448 | spin_unlock(&old_entry->lock); | |
449 | fsnotify_destroy_mark_by_entry(old_entry); | |
450 | fsnotify_put_mark(old_entry); /* pair to fsnotify_find mark_entry */ | |
451 | fsnotify_put_mark(old_entry); /* and kill it */ | |
74c3cbe3 AV |
452 | return 0; |
453 | } | |
454 | ||
74c3cbe3 AV |
455 | static void kill_rules(struct audit_tree *tree) |
456 | { | |
457 | struct audit_krule *rule, *next; | |
458 | struct audit_entry *entry; | |
459 | struct audit_buffer *ab; | |
460 | ||
461 | list_for_each_entry_safe(rule, next, &tree->rules, rlist) { | |
462 | entry = container_of(rule, struct audit_entry, rule); | |
463 | ||
464 | list_del_init(&rule->rlist); | |
465 | if (rule->tree) { | |
466 | /* not a half-baked one */ | |
467 | ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE); | |
9d960985 EP |
468 | audit_log_format(ab, "op="); |
469 | audit_log_string(ab, "remove rule"); | |
470 | audit_log_format(ab, " dir="); | |
74c3cbe3 | 471 | audit_log_untrustedstring(ab, rule->tree->pathname); |
9d960985 | 472 | audit_log_key(ab, rule->filterkey); |
74c3cbe3 AV |
473 | audit_log_format(ab, " list=%d res=1", rule->listnr); |
474 | audit_log_end(ab); | |
475 | rule->tree = NULL; | |
476 | list_del_rcu(&entry->list); | |
e45aa212 | 477 | list_del(&entry->rule.list); |
74c3cbe3 AV |
478 | call_rcu(&entry->rcu, audit_free_rule_rcu); |
479 | } | |
480 | } | |
481 | } | |
482 | ||
483 | /* | |
484 | * finish killing struct audit_tree | |
485 | */ | |
486 | static void prune_one(struct audit_tree *victim) | |
487 | { | |
488 | spin_lock(&hash_lock); | |
489 | while (!list_empty(&victim->chunks)) { | |
490 | struct node *p; | |
74c3cbe3 AV |
491 | |
492 | p = list_entry(victim->chunks.next, struct node, list); | |
74c3cbe3 | 493 | |
8f7b0ba1 | 494 | untag_chunk(p); |
74c3cbe3 AV |
495 | } |
496 | spin_unlock(&hash_lock); | |
497 | put_tree(victim); | |
498 | } | |
499 | ||
500 | /* trim the uncommitted chunks from tree */ | |
501 | ||
502 | static void trim_marked(struct audit_tree *tree) | |
503 | { | |
504 | struct list_head *p, *q; | |
505 | spin_lock(&hash_lock); | |
506 | if (tree->goner) { | |
507 | spin_unlock(&hash_lock); | |
508 | return; | |
509 | } | |
510 | /* reorder */ | |
511 | for (p = tree->chunks.next; p != &tree->chunks; p = q) { | |
512 | struct node *node = list_entry(p, struct node, list); | |
513 | q = p->next; | |
514 | if (node->index & (1U<<31)) { | |
515 | list_del_init(p); | |
516 | list_add(p, &tree->chunks); | |
517 | } | |
518 | } | |
519 | ||
520 | while (!list_empty(&tree->chunks)) { | |
521 | struct node *node; | |
74c3cbe3 AV |
522 | |
523 | node = list_entry(tree->chunks.next, struct node, list); | |
524 | ||
525 | /* have we run out of marked? */ | |
526 | if (!(node->index & (1U<<31))) | |
527 | break; | |
528 | ||
8f7b0ba1 | 529 | untag_chunk(node); |
74c3cbe3 AV |
530 | } |
531 | if (!tree->root && !tree->goner) { | |
532 | tree->goner = 1; | |
533 | spin_unlock(&hash_lock); | |
534 | mutex_lock(&audit_filter_mutex); | |
535 | kill_rules(tree); | |
536 | list_del_init(&tree->list); | |
537 | mutex_unlock(&audit_filter_mutex); | |
538 | prune_one(tree); | |
539 | } else { | |
540 | spin_unlock(&hash_lock); | |
541 | } | |
542 | } | |
543 | ||
916d7576 AV |
544 | static void audit_schedule_prune(void); |
545 | ||
74c3cbe3 AV |
546 | /* called with audit_filter_mutex */ |
547 | int audit_remove_tree_rule(struct audit_krule *rule) | |
548 | { | |
549 | struct audit_tree *tree; | |
550 | tree = rule->tree; | |
551 | if (tree) { | |
552 | spin_lock(&hash_lock); | |
553 | list_del_init(&rule->rlist); | |
554 | if (list_empty(&tree->rules) && !tree->goner) { | |
555 | tree->root = NULL; | |
556 | list_del_init(&tree->same_root); | |
557 | tree->goner = 1; | |
558 | list_move(&tree->list, &prune_list); | |
559 | rule->tree = NULL; | |
560 | spin_unlock(&hash_lock); | |
561 | audit_schedule_prune(); | |
562 | return 1; | |
563 | } | |
564 | rule->tree = NULL; | |
565 | spin_unlock(&hash_lock); | |
566 | return 1; | |
567 | } | |
568 | return 0; | |
569 | } | |
570 | ||
1f707137 AV |
571 | static int compare_root(struct vfsmount *mnt, void *arg) |
572 | { | |
573 | return mnt->mnt_root->d_inode == arg; | |
574 | } | |
575 | ||
74c3cbe3 AV |
576 | void audit_trim_trees(void) |
577 | { | |
578 | struct list_head cursor; | |
579 | ||
580 | mutex_lock(&audit_filter_mutex); | |
581 | list_add(&cursor, &tree_list); | |
582 | while (cursor.next != &tree_list) { | |
583 | struct audit_tree *tree; | |
98bc993f | 584 | struct path path; |
74c3cbe3 AV |
585 | struct vfsmount *root_mnt; |
586 | struct node *node; | |
74c3cbe3 AV |
587 | int err; |
588 | ||
589 | tree = container_of(cursor.next, struct audit_tree, list); | |
590 | get_tree(tree); | |
591 | list_del(&cursor); | |
592 | list_add(&cursor, &tree->list); | |
593 | mutex_unlock(&audit_filter_mutex); | |
594 | ||
98bc993f | 595 | err = kern_path(tree->pathname, 0, &path); |
74c3cbe3 AV |
596 | if (err) |
597 | goto skip_it; | |
598 | ||
589ff870 | 599 | root_mnt = collect_mounts(&path); |
98bc993f | 600 | path_put(&path); |
74c3cbe3 AV |
601 | if (!root_mnt) |
602 | goto skip_it; | |
603 | ||
74c3cbe3 AV |
604 | spin_lock(&hash_lock); |
605 | list_for_each_entry(node, &tree->chunks, list) { | |
28a3a7eb EP |
606 | struct audit_chunk *chunk = find_chunk(node); |
607 | /* this could be NULL if the watch is dieing else where... */ | |
608 | struct inode *inode = chunk->mark.inode; | |
74c3cbe3 | 609 | node->index |= 1U<<31; |
1f707137 AV |
610 | if (iterate_mounts(compare_root, inode, root_mnt)) |
611 | node->index &= ~(1U<<31); | |
74c3cbe3 AV |
612 | } |
613 | spin_unlock(&hash_lock); | |
614 | trim_marked(tree); | |
615 | put_tree(tree); | |
74c3cbe3 AV |
616 | drop_collected_mounts(root_mnt); |
617 | skip_it: | |
618 | mutex_lock(&audit_filter_mutex); | |
619 | } | |
620 | list_del(&cursor); | |
621 | mutex_unlock(&audit_filter_mutex); | |
622 | } | |
623 | ||
74c3cbe3 AV |
624 | int audit_make_tree(struct audit_krule *rule, char *pathname, u32 op) |
625 | { | |
626 | ||
627 | if (pathname[0] != '/' || | |
628 | rule->listnr != AUDIT_FILTER_EXIT || | |
5af75d8d | 629 | op != Audit_equal || |
74c3cbe3 AV |
630 | rule->inode_f || rule->watch || rule->tree) |
631 | return -EINVAL; | |
632 | rule->tree = alloc_tree(pathname); | |
633 | if (!rule->tree) | |
634 | return -ENOMEM; | |
635 | return 0; | |
636 | } | |
637 | ||
638 | void audit_put_tree(struct audit_tree *tree) | |
639 | { | |
640 | put_tree(tree); | |
641 | } | |
642 | ||
1f707137 AV |
643 | static int tag_mount(struct vfsmount *mnt, void *arg) |
644 | { | |
645 | return tag_chunk(mnt->mnt_root->d_inode, arg); | |
646 | } | |
647 | ||
74c3cbe3 AV |
648 | /* called with audit_filter_mutex */ |
649 | int audit_add_tree_rule(struct audit_krule *rule) | |
650 | { | |
651 | struct audit_tree *seed = rule->tree, *tree; | |
98bc993f | 652 | struct path path; |
1f707137 | 653 | struct vfsmount *mnt; |
74c3cbe3 AV |
654 | int err; |
655 | ||
656 | list_for_each_entry(tree, &tree_list, list) { | |
657 | if (!strcmp(seed->pathname, tree->pathname)) { | |
658 | put_tree(seed); | |
659 | rule->tree = tree; | |
660 | list_add(&rule->rlist, &tree->rules); | |
661 | return 0; | |
662 | } | |
663 | } | |
664 | tree = seed; | |
665 | list_add(&tree->list, &tree_list); | |
666 | list_add(&rule->rlist, &tree->rules); | |
667 | /* do not set rule->tree yet */ | |
668 | mutex_unlock(&audit_filter_mutex); | |
669 | ||
98bc993f | 670 | err = kern_path(tree->pathname, 0, &path); |
74c3cbe3 AV |
671 | if (err) |
672 | goto Err; | |
589ff870 | 673 | mnt = collect_mounts(&path); |
98bc993f | 674 | path_put(&path); |
74c3cbe3 AV |
675 | if (!mnt) { |
676 | err = -ENOMEM; | |
677 | goto Err; | |
678 | } | |
74c3cbe3 AV |
679 | |
680 | get_tree(tree); | |
1f707137 | 681 | err = iterate_mounts(tag_mount, tree, mnt); |
74c3cbe3 AV |
682 | drop_collected_mounts(mnt); |
683 | ||
684 | if (!err) { | |
685 | struct node *node; | |
686 | spin_lock(&hash_lock); | |
687 | list_for_each_entry(node, &tree->chunks, list) | |
688 | node->index &= ~(1U<<31); | |
689 | spin_unlock(&hash_lock); | |
690 | } else { | |
691 | trim_marked(tree); | |
692 | goto Err; | |
693 | } | |
694 | ||
695 | mutex_lock(&audit_filter_mutex); | |
696 | if (list_empty(&rule->rlist)) { | |
697 | put_tree(tree); | |
698 | return -ENOENT; | |
699 | } | |
700 | rule->tree = tree; | |
701 | put_tree(tree); | |
702 | ||
703 | return 0; | |
704 | Err: | |
705 | mutex_lock(&audit_filter_mutex); | |
706 | list_del_init(&tree->list); | |
707 | list_del_init(&tree->rules); | |
708 | put_tree(tree); | |
709 | return err; | |
710 | } | |
711 | ||
712 | int audit_tag_tree(char *old, char *new) | |
713 | { | |
714 | struct list_head cursor, barrier; | |
715 | int failed = 0; | |
2096f759 | 716 | struct path path1, path2; |
74c3cbe3 | 717 | struct vfsmount *tagged; |
74c3cbe3 AV |
718 | int err; |
719 | ||
2096f759 | 720 | err = kern_path(new, 0, &path2); |
74c3cbe3 AV |
721 | if (err) |
722 | return err; | |
2096f759 AV |
723 | tagged = collect_mounts(&path2); |
724 | path_put(&path2); | |
74c3cbe3 AV |
725 | if (!tagged) |
726 | return -ENOMEM; | |
727 | ||
2096f759 | 728 | err = kern_path(old, 0, &path1); |
74c3cbe3 AV |
729 | if (err) { |
730 | drop_collected_mounts(tagged); | |
731 | return err; | |
732 | } | |
74c3cbe3 | 733 | |
74c3cbe3 AV |
734 | mutex_lock(&audit_filter_mutex); |
735 | list_add(&barrier, &tree_list); | |
736 | list_add(&cursor, &barrier); | |
737 | ||
738 | while (cursor.next != &tree_list) { | |
739 | struct audit_tree *tree; | |
2096f759 | 740 | int good_one = 0; |
74c3cbe3 AV |
741 | |
742 | tree = container_of(cursor.next, struct audit_tree, list); | |
743 | get_tree(tree); | |
744 | list_del(&cursor); | |
745 | list_add(&cursor, &tree->list); | |
746 | mutex_unlock(&audit_filter_mutex); | |
747 | ||
2096f759 AV |
748 | err = kern_path(tree->pathname, 0, &path2); |
749 | if (!err) { | |
750 | good_one = path_is_under(&path1, &path2); | |
751 | path_put(&path2); | |
74c3cbe3 AV |
752 | } |
753 | ||
2096f759 | 754 | if (!good_one) { |
74c3cbe3 AV |
755 | put_tree(tree); |
756 | mutex_lock(&audit_filter_mutex); | |
757 | continue; | |
758 | } | |
74c3cbe3 | 759 | |
1f707137 | 760 | failed = iterate_mounts(tag_mount, tree, tagged); |
74c3cbe3 AV |
761 | if (failed) { |
762 | put_tree(tree); | |
763 | mutex_lock(&audit_filter_mutex); | |
764 | break; | |
765 | } | |
766 | ||
767 | mutex_lock(&audit_filter_mutex); | |
768 | spin_lock(&hash_lock); | |
769 | if (!tree->goner) { | |
770 | list_del(&tree->list); | |
771 | list_add(&tree->list, &tree_list); | |
772 | } | |
773 | spin_unlock(&hash_lock); | |
774 | put_tree(tree); | |
775 | } | |
776 | ||
777 | while (barrier.prev != &tree_list) { | |
778 | struct audit_tree *tree; | |
779 | ||
780 | tree = container_of(barrier.prev, struct audit_tree, list); | |
781 | get_tree(tree); | |
782 | list_del(&tree->list); | |
783 | list_add(&tree->list, &barrier); | |
784 | mutex_unlock(&audit_filter_mutex); | |
785 | ||
786 | if (!failed) { | |
787 | struct node *node; | |
788 | spin_lock(&hash_lock); | |
789 | list_for_each_entry(node, &tree->chunks, list) | |
790 | node->index &= ~(1U<<31); | |
791 | spin_unlock(&hash_lock); | |
792 | } else { | |
793 | trim_marked(tree); | |
794 | } | |
795 | ||
796 | put_tree(tree); | |
797 | mutex_lock(&audit_filter_mutex); | |
798 | } | |
799 | list_del(&barrier); | |
800 | list_del(&cursor); | |
74c3cbe3 | 801 | mutex_unlock(&audit_filter_mutex); |
2096f759 | 802 | path_put(&path1); |
74c3cbe3 AV |
803 | drop_collected_mounts(tagged); |
804 | return failed; | |
805 | } | |
806 | ||
807 | /* | |
808 | * That gets run when evict_chunk() ends up needing to kill audit_tree. | |
916d7576 | 809 | * Runs from a separate thread. |
74c3cbe3 | 810 | */ |
916d7576 | 811 | static int prune_tree_thread(void *unused) |
74c3cbe3 | 812 | { |
916d7576 | 813 | mutex_lock(&audit_cmd_mutex); |
74c3cbe3 AV |
814 | mutex_lock(&audit_filter_mutex); |
815 | ||
816 | while (!list_empty(&prune_list)) { | |
817 | struct audit_tree *victim; | |
818 | ||
819 | victim = list_entry(prune_list.next, struct audit_tree, list); | |
820 | list_del_init(&victim->list); | |
821 | ||
822 | mutex_unlock(&audit_filter_mutex); | |
823 | ||
824 | prune_one(victim); | |
825 | ||
826 | mutex_lock(&audit_filter_mutex); | |
827 | } | |
828 | ||
829 | mutex_unlock(&audit_filter_mutex); | |
916d7576 AV |
830 | mutex_unlock(&audit_cmd_mutex); |
831 | return 0; | |
832 | } | |
833 | ||
834 | static void audit_schedule_prune(void) | |
835 | { | |
836 | kthread_run(prune_tree_thread, NULL, "audit_prune_tree"); | |
837 | } | |
838 | ||
839 | /* | |
840 | * ... and that one is done if evict_chunk() decides to delay until the end | |
841 | * of syscall. Runs synchronously. | |
842 | */ | |
843 | void audit_kill_trees(struct list_head *list) | |
844 | { | |
845 | mutex_lock(&audit_cmd_mutex); | |
846 | mutex_lock(&audit_filter_mutex); | |
847 | ||
848 | while (!list_empty(list)) { | |
849 | struct audit_tree *victim; | |
850 | ||
851 | victim = list_entry(list->next, struct audit_tree, list); | |
852 | kill_rules(victim); | |
853 | list_del_init(&victim->list); | |
854 | ||
855 | mutex_unlock(&audit_filter_mutex); | |
856 | ||
857 | prune_one(victim); | |
858 | ||
859 | mutex_lock(&audit_filter_mutex); | |
860 | } | |
861 | ||
862 | mutex_unlock(&audit_filter_mutex); | |
863 | mutex_unlock(&audit_cmd_mutex); | |
74c3cbe3 AV |
864 | } |
865 | ||
866 | /* | |
867 | * Here comes the stuff asynchronous to auditctl operations | |
868 | */ | |
869 | ||
74c3cbe3 AV |
870 | static void evict_chunk(struct audit_chunk *chunk) |
871 | { | |
872 | struct audit_tree *owner; | |
916d7576 AV |
873 | struct list_head *postponed = audit_killed_trees(); |
874 | int need_prune = 0; | |
74c3cbe3 AV |
875 | int n; |
876 | ||
877 | if (chunk->dead) | |
878 | return; | |
879 | ||
880 | chunk->dead = 1; | |
881 | mutex_lock(&audit_filter_mutex); | |
882 | spin_lock(&hash_lock); | |
883 | while (!list_empty(&chunk->trees)) { | |
884 | owner = list_entry(chunk->trees.next, | |
885 | struct audit_tree, same_root); | |
886 | owner->goner = 1; | |
887 | owner->root = NULL; | |
888 | list_del_init(&owner->same_root); | |
889 | spin_unlock(&hash_lock); | |
916d7576 AV |
890 | if (!postponed) { |
891 | kill_rules(owner); | |
892 | list_move(&owner->list, &prune_list); | |
893 | need_prune = 1; | |
894 | } else { | |
895 | list_move(&owner->list, postponed); | |
896 | } | |
74c3cbe3 AV |
897 | spin_lock(&hash_lock); |
898 | } | |
899 | list_del_rcu(&chunk->hash); | |
900 | for (n = 0; n < chunk->count; n++) | |
901 | list_del_init(&chunk->owners[n].list); | |
902 | spin_unlock(&hash_lock); | |
916d7576 AV |
903 | if (need_prune) |
904 | audit_schedule_prune(); | |
74c3cbe3 AV |
905 | mutex_unlock(&audit_filter_mutex); |
906 | } | |
907 | ||
28a3a7eb | 908 | static int audit_tree_handle_event(struct fsnotify_group *group, struct fsnotify_event *event) |
74c3cbe3 | 909 | { |
28a3a7eb EP |
910 | BUG(); |
911 | return -EOPNOTSUPP; | |
912 | } | |
74c3cbe3 | 913 | |
28a3a7eb EP |
914 | static void audit_tree_freeing_mark(struct fsnotify_mark_entry *entry, struct fsnotify_group *group) |
915 | { | |
916 | struct audit_chunk *chunk = container_of(entry, struct audit_chunk, mark); | |
917 | ||
918 | evict_chunk(chunk); | |
919 | fsnotify_put_mark(entry); | |
74c3cbe3 AV |
920 | } |
921 | ||
7b0a04fb | 922 | static bool audit_tree_send_event(struct fsnotify_group *group, struct inode *inode, |
8112e2d6 | 923 | __u32 mask, void *data, int data_type) |
74c3cbe3 | 924 | { |
28a3a7eb | 925 | return 0; |
74c3cbe3 AV |
926 | } |
927 | ||
28a3a7eb EP |
928 | static const struct fsnotify_ops audit_tree_ops = { |
929 | .handle_event = audit_tree_handle_event, | |
930 | .should_send_event = audit_tree_send_event, | |
931 | .free_group_priv = NULL, | |
932 | .free_event_priv = NULL, | |
933 | .freeing_mark = audit_tree_freeing_mark, | |
74c3cbe3 AV |
934 | }; |
935 | ||
936 | static int __init audit_tree_init(void) | |
937 | { | |
938 | int i; | |
939 | ||
ffab8340 | 940 | audit_tree_group = fsnotify_alloc_group(0, &audit_tree_ops); |
28a3a7eb EP |
941 | if (IS_ERR(audit_tree_group)) |
942 | audit_panic("cannot initialize fsnotify group for rectree watches"); | |
74c3cbe3 AV |
943 | |
944 | for (i = 0; i < HASH_SIZE; i++) | |
945 | INIT_LIST_HEAD(&chunk_hash_heads[i]); | |
946 | ||
947 | return 0; | |
948 | } | |
949 | __initcall(audit_tree_init); |