Commit | Line | Data |
---|---|---|
b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
74c3cbe3 | 2 | #include "audit.h" |
28a3a7eb | 3 | #include <linux/fsnotify_backend.h> |
74c3cbe3 AV |
4 | #include <linux/namei.h> |
5 | #include <linux/mount.h> | |
916d7576 | 6 | #include <linux/kthread.h> |
9d2378f8 | 7 | #include <linux/refcount.h> |
5a0e3ad6 | 8 | #include <linux/slab.h> |
74c3cbe3 AV |
9 | |
10 | struct audit_tree; | |
11 | struct audit_chunk; | |
12 | ||
13 | struct audit_tree { | |
9d2378f8 | 14 | refcount_t count; |
74c3cbe3 AV |
15 | int goner; |
16 | struct audit_chunk *root; | |
17 | struct list_head chunks; | |
18 | struct list_head rules; | |
19 | struct list_head list; | |
20 | struct list_head same_root; | |
21 | struct rcu_head head; | |
22 | char pathname[]; | |
23 | }; | |
24 | ||
25 | struct audit_chunk { | |
26 | struct list_head hash; | |
8d20d6e9 | 27 | unsigned long key; |
e61ce867 | 28 | struct fsnotify_mark mark; |
74c3cbe3 AV |
29 | struct list_head trees; /* with root here */ |
30 | int dead; | |
31 | int count; | |
8f7b0ba1 | 32 | atomic_long_t refs; |
74c3cbe3 AV |
33 | struct rcu_head head; |
34 | struct node { | |
35 | struct list_head list; | |
36 | struct audit_tree *owner; | |
37 | unsigned index; /* index; upper bit indicates 'will prune' */ | |
38 | } owners[]; | |
39 | }; | |
40 | ||
41 | static LIST_HEAD(tree_list); | |
42 | static LIST_HEAD(prune_list); | |
f1aaf262 | 43 | static struct task_struct *prune_thread; |
74c3cbe3 AV |
44 | |
45 | /* | |
46 | * One struct chunk is attached to each inode of interest. | |
47 | * We replace struct chunk on tagging/untagging. | |
48 | * Rules have pointer to struct audit_tree. | |
49 | * Rules have struct list_head rlist forming a list of rules over | |
50 | * the same tree. | |
51 | * References to struct chunk are collected at audit_inode{,_child}() | |
52 | * time and used in AUDIT_TREE rule matching. | |
53 | * These references are dropped at the same time we are calling | |
54 | * audit_free_names(), etc. | |
55 | * | |
56 | * Cyclic lists galore: | |
57 | * tree.chunks anchors chunk.owners[].list hash_lock | |
58 | * tree.rules anchors rule.rlist audit_filter_mutex | |
59 | * chunk.trees anchors tree.same_root hash_lock | |
60 | * chunk.hash is a hash with middle bits of watch.inode as | |
61 | * a hash function. RCU, hash_lock | |
62 | * | |
63 | * tree is refcounted; one reference for "some rules on rules_list refer to | |
64 | * it", one for each chunk with pointer to it. | |
65 | * | |
28a3a7eb | 66 | * chunk is refcounted by embedded fsnotify_mark + .refs (non-zero refcount |
8f7b0ba1 | 67 | * of watch contributes 1 to .refs). |
74c3cbe3 AV |
68 | * |
69 | * node.index allows to get from node.list to containing chunk. | |
70 | * MSB of that sucker is stolen to mark taggings that we might have to | |
71 | * revert - several operations have very unpleasant cleanup logics and | |
72 | * that makes a difference. Some. | |
73 | */ | |
74 | ||
28a3a7eb | 75 | static struct fsnotify_group *audit_tree_group; |
74c3cbe3 AV |
76 | |
77 | static struct audit_tree *alloc_tree(const char *s) | |
78 | { | |
79 | struct audit_tree *tree; | |
80 | ||
81 | tree = kmalloc(sizeof(struct audit_tree) + strlen(s) + 1, GFP_KERNEL); | |
82 | if (tree) { | |
9d2378f8 | 83 | refcount_set(&tree->count, 1); |
74c3cbe3 AV |
84 | tree->goner = 0; |
85 | INIT_LIST_HEAD(&tree->chunks); | |
86 | INIT_LIST_HEAD(&tree->rules); | |
87 | INIT_LIST_HEAD(&tree->list); | |
88 | INIT_LIST_HEAD(&tree->same_root); | |
89 | tree->root = NULL; | |
90 | strcpy(tree->pathname, s); | |
91 | } | |
92 | return tree; | |
93 | } | |
94 | ||
95 | static inline void get_tree(struct audit_tree *tree) | |
96 | { | |
9d2378f8 | 97 | refcount_inc(&tree->count); |
74c3cbe3 AV |
98 | } |
99 | ||
74c3cbe3 AV |
100 | static inline void put_tree(struct audit_tree *tree) |
101 | { | |
9d2378f8 | 102 | if (refcount_dec_and_test(&tree->count)) |
3b097c46 | 103 | kfree_rcu(tree, head); |
74c3cbe3 AV |
104 | } |
105 | ||
106 | /* to avoid bringing the entire thing in audit.h */ | |
107 | const char *audit_tree_path(struct audit_tree *tree) | |
108 | { | |
109 | return tree->pathname; | |
110 | } | |
111 | ||
8f7b0ba1 | 112 | static void free_chunk(struct audit_chunk *chunk) |
74c3cbe3 | 113 | { |
74c3cbe3 AV |
114 | int i; |
115 | ||
116 | for (i = 0; i < chunk->count; i++) { | |
117 | if (chunk->owners[i].owner) | |
118 | put_tree(chunk->owners[i].owner); | |
119 | } | |
120 | kfree(chunk); | |
121 | } | |
122 | ||
8f7b0ba1 | 123 | void audit_put_chunk(struct audit_chunk *chunk) |
74c3cbe3 | 124 | { |
8f7b0ba1 AV |
125 | if (atomic_long_dec_and_test(&chunk->refs)) |
126 | free_chunk(chunk); | |
74c3cbe3 AV |
127 | } |
128 | ||
8f7b0ba1 | 129 | static void __put_chunk(struct rcu_head *rcu) |
74c3cbe3 | 130 | { |
8f7b0ba1 AV |
131 | struct audit_chunk *chunk = container_of(rcu, struct audit_chunk, head); |
132 | audit_put_chunk(chunk); | |
74c3cbe3 AV |
133 | } |
134 | ||
e61ce867 | 135 | static void audit_tree_destroy_watch(struct fsnotify_mark *entry) |
28a3a7eb EP |
136 | { |
137 | struct audit_chunk *chunk = container_of(entry, struct audit_chunk, mark); | |
138 | call_rcu(&chunk->head, __put_chunk); | |
139 | } | |
140 | ||
141 | static struct audit_chunk *alloc_chunk(int count) | |
142 | { | |
143 | struct audit_chunk *chunk; | |
144 | size_t size; | |
145 | int i; | |
146 | ||
147 | size = offsetof(struct audit_chunk, owners) + count * sizeof(struct node); | |
148 | chunk = kzalloc(size, GFP_KERNEL); | |
149 | if (!chunk) | |
150 | return NULL; | |
151 | ||
152 | INIT_LIST_HEAD(&chunk->hash); | |
153 | INIT_LIST_HEAD(&chunk->trees); | |
154 | chunk->count = count; | |
155 | atomic_long_set(&chunk->refs, 1); | |
156 | for (i = 0; i < count; i++) { | |
157 | INIT_LIST_HEAD(&chunk->owners[i].list); | |
158 | chunk->owners[i].index = i; | |
159 | } | |
054c636e | 160 | fsnotify_init_mark(&chunk->mark, audit_tree_group); |
799b6014 | 161 | chunk->mark.mask = FS_IN_IGNORED; |
28a3a7eb EP |
162 | return chunk; |
163 | } | |
164 | ||
74c3cbe3 AV |
165 | enum {HASH_SIZE = 128}; |
166 | static struct list_head chunk_hash_heads[HASH_SIZE]; | |
167 | static __cacheline_aligned_in_smp DEFINE_SPINLOCK(hash_lock); | |
168 | ||
f410ff65 JK |
169 | /* Function to return search key in our hash from inode. */ |
170 | static unsigned long inode_to_key(const struct inode *inode) | |
74c3cbe3 | 171 | { |
36f10f55 AG |
172 | /* Use address pointed to by connector->obj as the key */ |
173 | return (unsigned long)&inode->i_fsnotify_marks; | |
f410ff65 JK |
174 | } |
175 | ||
f410ff65 JK |
176 | static inline struct list_head *chunk_hash(unsigned long key) |
177 | { | |
178 | unsigned long n = key / L1_CACHE_BYTES; | |
74c3cbe3 AV |
179 | return chunk_hash_heads + n % HASH_SIZE; |
180 | } | |
181 | ||
9f16d2e6 | 182 | /* hash_lock & entry->group->mark_mutex is held by caller */ |
74c3cbe3 AV |
183 | static void insert_hash(struct audit_chunk *chunk) |
184 | { | |
28a3a7eb EP |
185 | struct list_head *list; |
186 | ||
1635e572 JK |
187 | /* |
188 | * Make sure chunk is fully initialized before making it visible in the | |
189 | * hash. Pairs with a data dependency barrier in READ_ONCE() in | |
190 | * audit_tree_lookup(). | |
191 | */ | |
192 | smp_wmb(); | |
8d20d6e9 JK |
193 | WARN_ON_ONCE(!chunk->key); |
194 | list = chunk_hash(chunk->key); | |
74c3cbe3 AV |
195 | list_add_rcu(&chunk->hash, list); |
196 | } | |
197 | ||
198 | /* called under rcu_read_lock */ | |
199 | struct audit_chunk *audit_tree_lookup(const struct inode *inode) | |
200 | { | |
f410ff65 JK |
201 | unsigned long key = inode_to_key(inode); |
202 | struct list_head *list = chunk_hash(key); | |
6793a051 | 203 | struct audit_chunk *p; |
74c3cbe3 | 204 | |
6793a051 | 205 | list_for_each_entry_rcu(p, list, hash) { |
1635e572 JK |
206 | /* |
207 | * We use a data dependency barrier in READ_ONCE() to make sure | |
208 | * the chunk we see is fully initialized. | |
209 | */ | |
210 | if (READ_ONCE(p->key) == key) { | |
8f7b0ba1 | 211 | atomic_long_inc(&p->refs); |
74c3cbe3 AV |
212 | return p; |
213 | } | |
214 | } | |
215 | return NULL; | |
216 | } | |
217 | ||
6f1b5d7a | 218 | bool audit_tree_match(struct audit_chunk *chunk, struct audit_tree *tree) |
74c3cbe3 AV |
219 | { |
220 | int n; | |
221 | for (n = 0; n < chunk->count; n++) | |
222 | if (chunk->owners[n].owner == tree) | |
6f1b5d7a YB |
223 | return true; |
224 | return false; | |
74c3cbe3 AV |
225 | } |
226 | ||
227 | /* tagging and untagging inodes with trees */ | |
228 | ||
8f7b0ba1 AV |
229 | static struct audit_chunk *find_chunk(struct node *p) |
230 | { | |
231 | int index = p->index & ~(1U<<31); | |
232 | p -= index; | |
233 | return container_of(p, struct audit_chunk, owners[0]); | |
234 | } | |
235 | ||
d31b326d JK |
236 | static void replace_chunk(struct audit_chunk *new, struct audit_chunk *old, |
237 | struct node *skip) | |
238 | { | |
239 | struct audit_tree *owner; | |
240 | int i, j; | |
241 | ||
242 | new->key = old->key; | |
243 | list_splice_init(&old->trees, &new->trees); | |
244 | list_for_each_entry(owner, &new->trees, same_root) | |
245 | owner->root = new; | |
246 | for (i = j = 0; j < old->count; i++, j++) { | |
247 | if (&old->owners[j] == skip) { | |
248 | i--; | |
249 | continue; | |
250 | } | |
251 | owner = old->owners[j].owner; | |
252 | new->owners[i].owner = owner; | |
253 | new->owners[i].index = old->owners[j].index - j + i; | |
254 | if (!owner) /* result of earlier fallback */ | |
255 | continue; | |
256 | get_tree(owner); | |
257 | list_replace_init(&old->owners[j].list, &new->owners[i].list); | |
258 | } | |
259 | /* | |
260 | * Make sure chunk is fully initialized before making it visible in the | |
261 | * hash. Pairs with a data dependency barrier in READ_ONCE() in | |
262 | * audit_tree_lookup(). | |
263 | */ | |
264 | smp_wmb(); | |
265 | list_replace_rcu(&old->hash, &new->hash); | |
266 | } | |
267 | ||
8f7b0ba1 | 268 | static void untag_chunk(struct node *p) |
74c3cbe3 | 269 | { |
8f7b0ba1 | 270 | struct audit_chunk *chunk = find_chunk(p); |
e61ce867 | 271 | struct fsnotify_mark *entry = &chunk->mark; |
f7a998a9 | 272 | struct audit_chunk *new = NULL; |
74c3cbe3 AV |
273 | struct audit_tree *owner; |
274 | int size = chunk->count - 1; | |
74c3cbe3 | 275 | |
28a3a7eb | 276 | fsnotify_get_mark(entry); |
8f7b0ba1 AV |
277 | |
278 | spin_unlock(&hash_lock); | |
279 | ||
f7a998a9 AV |
280 | if (size) |
281 | new = alloc_chunk(size); | |
282 | ||
be29d20f | 283 | mutex_lock(&entry->group->mark_mutex); |
6b3f05d2 JK |
284 | /* |
285 | * mark_mutex protects mark from getting detached and thus also from | |
36f10f55 | 286 | * mark->connector->obj getting NULL. |
6b3f05d2 | 287 | */ |
43471d15 | 288 | if (chunk->dead || !(entry->flags & FSNOTIFY_MARK_FLAG_ATTACHED)) { |
be29d20f | 289 | mutex_unlock(&entry->group->mark_mutex); |
f7a998a9 | 290 | if (new) |
7b129323 | 291 | fsnotify_put_mark(&new->mark); |
8f7b0ba1 | 292 | goto out; |
74c3cbe3 AV |
293 | } |
294 | ||
295 | owner = p->owner; | |
296 | ||
297 | if (!size) { | |
298 | chunk->dead = 1; | |
299 | spin_lock(&hash_lock); | |
300 | list_del_init(&chunk->trees); | |
301 | if (owner->root == chunk) | |
302 | owner->root = NULL; | |
303 | list_del_init(&p->list); | |
304 | list_del_rcu(&chunk->hash); | |
305 | spin_unlock(&hash_lock); | |
b1e4603b | 306 | fsnotify_detach_mark(entry); |
be29d20f | 307 | mutex_unlock(&entry->group->mark_mutex); |
b1e4603b | 308 | fsnotify_free_mark(entry); |
8f7b0ba1 | 309 | goto out; |
74c3cbe3 AV |
310 | } |
311 | ||
74c3cbe3 AV |
312 | if (!new) |
313 | goto Fallback; | |
f7a998a9 | 314 | |
36f10f55 AG |
315 | if (fsnotify_add_mark_locked(&new->mark, entry->connector->obj, |
316 | FSNOTIFY_OBJ_TYPE_INODE, 1)) { | |
0fe33aae | 317 | fsnotify_put_mark(&new->mark); |
74c3cbe3 AV |
318 | goto Fallback; |
319 | } | |
320 | ||
321 | chunk->dead = 1; | |
322 | spin_lock(&hash_lock); | |
74c3cbe3 AV |
323 | if (owner->root == chunk) { |
324 | list_del_init(&owner->same_root); | |
325 | owner->root = NULL; | |
326 | } | |
d31b326d | 327 | list_del_init(&p->list); |
1635e572 | 328 | /* |
d31b326d JK |
329 | * This has to go last when updating chunk as once replace_chunk() is |
330 | * called, new RCU readers can see the new chunk. | |
1635e572 | 331 | */ |
d31b326d | 332 | replace_chunk(new, chunk, p); |
74c3cbe3 | 333 | spin_unlock(&hash_lock); |
b1e4603b | 334 | fsnotify_detach_mark(entry); |
be29d20f | 335 | mutex_unlock(&entry->group->mark_mutex); |
b1e4603b | 336 | fsnotify_free_mark(entry); |
b3e8692b | 337 | fsnotify_put_mark(&new->mark); /* drop initial reference */ |
8f7b0ba1 | 338 | goto out; |
74c3cbe3 AV |
339 | |
340 | Fallback: | |
341 | // do the best we can | |
342 | spin_lock(&hash_lock); | |
343 | if (owner->root == chunk) { | |
344 | list_del_init(&owner->same_root); | |
345 | owner->root = NULL; | |
346 | } | |
347 | list_del_init(&p->list); | |
348 | p->owner = NULL; | |
349 | put_tree(owner); | |
350 | spin_unlock(&hash_lock); | |
be29d20f | 351 | mutex_unlock(&entry->group->mark_mutex); |
8f7b0ba1 | 352 | out: |
28a3a7eb | 353 | fsnotify_put_mark(entry); |
8f7b0ba1 | 354 | spin_lock(&hash_lock); |
74c3cbe3 AV |
355 | } |
356 | ||
a5789b07 | 357 | /* Call with group->mark_mutex held, releases it */ |
74c3cbe3 AV |
358 | static int create_chunk(struct inode *inode, struct audit_tree *tree) |
359 | { | |
e61ce867 | 360 | struct fsnotify_mark *entry; |
74c3cbe3 | 361 | struct audit_chunk *chunk = alloc_chunk(1); |
a5789b07 JK |
362 | |
363 | if (!chunk) { | |
364 | mutex_unlock(&audit_tree_group->mark_mutex); | |
74c3cbe3 | 365 | return -ENOMEM; |
a5789b07 | 366 | } |
74c3cbe3 | 367 | |
28a3a7eb | 368 | entry = &chunk->mark; |
a5789b07 JK |
369 | if (fsnotify_add_inode_mark_locked(entry, inode, 0)) { |
370 | mutex_unlock(&audit_tree_group->mark_mutex); | |
0fe33aae | 371 | fsnotify_put_mark(entry); |
74c3cbe3 AV |
372 | return -ENOSPC; |
373 | } | |
374 | ||
74c3cbe3 AV |
375 | spin_lock(&hash_lock); |
376 | if (tree->goner) { | |
377 | spin_unlock(&hash_lock); | |
378 | chunk->dead = 1; | |
b1e4603b | 379 | fsnotify_detach_mark(entry); |
a5789b07 | 380 | mutex_unlock(&audit_tree_group->mark_mutex); |
b1e4603b | 381 | fsnotify_free_mark(entry); |
28a3a7eb | 382 | fsnotify_put_mark(entry); |
74c3cbe3 AV |
383 | return 0; |
384 | } | |
385 | chunk->owners[0].index = (1U << 31); | |
386 | chunk->owners[0].owner = tree; | |
387 | get_tree(tree); | |
388 | list_add(&chunk->owners[0].list, &tree->chunks); | |
389 | if (!tree->root) { | |
390 | tree->root = chunk; | |
391 | list_add(&tree->same_root, &chunk->trees); | |
392 | } | |
8d20d6e9 | 393 | chunk->key = inode_to_key(inode); |
1635e572 JK |
394 | /* |
395 | * Inserting into the hash table has to go last as once we do that RCU | |
396 | * readers can see the chunk. | |
397 | */ | |
74c3cbe3 AV |
398 | insert_hash(chunk); |
399 | spin_unlock(&hash_lock); | |
a5789b07 | 400 | mutex_unlock(&audit_tree_group->mark_mutex); |
b3e8692b | 401 | fsnotify_put_mark(entry); /* drop initial reference */ |
74c3cbe3 AV |
402 | return 0; |
403 | } | |
404 | ||
405 | /* the first tagged inode becomes root of tree */ | |
406 | static int tag_chunk(struct inode *inode, struct audit_tree *tree) | |
407 | { | |
e61ce867 | 408 | struct fsnotify_mark *old_entry, *chunk_entry; |
74c3cbe3 AV |
409 | struct audit_chunk *chunk, *old; |
410 | struct node *p; | |
411 | int n; | |
412 | ||
a5789b07 | 413 | mutex_lock(&audit_tree_group->mark_mutex); |
b1362edf JK |
414 | old_entry = fsnotify_find_mark(&inode->i_fsnotify_marks, |
415 | audit_tree_group); | |
28a3a7eb | 416 | if (!old_entry) |
74c3cbe3 AV |
417 | return create_chunk(inode, tree); |
418 | ||
28a3a7eb | 419 | old = container_of(old_entry, struct audit_chunk, mark); |
74c3cbe3 AV |
420 | |
421 | /* are we already there? */ | |
422 | spin_lock(&hash_lock); | |
423 | for (n = 0; n < old->count; n++) { | |
424 | if (old->owners[n].owner == tree) { | |
425 | spin_unlock(&hash_lock); | |
a5789b07 | 426 | mutex_unlock(&audit_tree_group->mark_mutex); |
28a3a7eb | 427 | fsnotify_put_mark(old_entry); |
74c3cbe3 AV |
428 | return 0; |
429 | } | |
430 | } | |
431 | spin_unlock(&hash_lock); | |
432 | ||
433 | chunk = alloc_chunk(old->count + 1); | |
b4c30aad | 434 | if (!chunk) { |
a5789b07 | 435 | mutex_unlock(&audit_tree_group->mark_mutex); |
28a3a7eb | 436 | fsnotify_put_mark(old_entry); |
74c3cbe3 | 437 | return -ENOMEM; |
b4c30aad | 438 | } |
74c3cbe3 | 439 | |
28a3a7eb EP |
440 | chunk_entry = &chunk->mark; |
441 | ||
6b3f05d2 JK |
442 | /* |
443 | * mark_mutex protects mark from getting detached and thus also from | |
36f10f55 | 444 | * mark->connector->obj getting NULL. |
6b3f05d2 | 445 | */ |
43471d15 | 446 | if (!(old_entry->flags & FSNOTIFY_MARK_FLAG_ATTACHED)) { |
28a3a7eb | 447 | /* old_entry is being shot, lets just lie */ |
a5789b07 | 448 | mutex_unlock(&audit_tree_group->mark_mutex); |
28a3a7eb | 449 | fsnotify_put_mark(old_entry); |
7b129323 | 450 | fsnotify_put_mark(&chunk->mark); |
28a3a7eb EP |
451 | return -ENOENT; |
452 | } | |
453 | ||
36f10f55 AG |
454 | if (fsnotify_add_mark_locked(chunk_entry, old_entry->connector->obj, |
455 | FSNOTIFY_OBJ_TYPE_INODE, 1)) { | |
a5789b07 | 456 | mutex_unlock(&audit_tree_group->mark_mutex); |
0fe33aae | 457 | fsnotify_put_mark(chunk_entry); |
28a3a7eb | 458 | fsnotify_put_mark(old_entry); |
74c3cbe3 AV |
459 | return -ENOSPC; |
460 | } | |
28a3a7eb | 461 | |
74c3cbe3 AV |
462 | spin_lock(&hash_lock); |
463 | if (tree->goner) { | |
464 | spin_unlock(&hash_lock); | |
465 | chunk->dead = 1; | |
b1e4603b | 466 | fsnotify_detach_mark(chunk_entry); |
a5789b07 | 467 | mutex_unlock(&audit_tree_group->mark_mutex); |
b1e4603b | 468 | fsnotify_free_mark(chunk_entry); |
28a3a7eb EP |
469 | fsnotify_put_mark(chunk_entry); |
470 | fsnotify_put_mark(old_entry); | |
74c3cbe3 AV |
471 | return 0; |
472 | } | |
d31b326d | 473 | p = &chunk->owners[chunk->count - 1]; |
74c3cbe3 AV |
474 | p->index = (chunk->count - 1) | (1U<<31); |
475 | p->owner = tree; | |
476 | get_tree(tree); | |
477 | list_add(&p->list, &tree->chunks); | |
74c3cbe3 AV |
478 | old->dead = 1; |
479 | if (!tree->root) { | |
480 | tree->root = chunk; | |
481 | list_add(&tree->same_root, &chunk->trees); | |
482 | } | |
1635e572 | 483 | /* |
d31b326d JK |
484 | * This has to go last when updating chunk as once replace_chunk() is |
485 | * called, new RCU readers can see the new chunk. | |
1635e572 | 486 | */ |
d31b326d | 487 | replace_chunk(chunk, old, NULL); |
74c3cbe3 | 488 | spin_unlock(&hash_lock); |
b1e4603b | 489 | fsnotify_detach_mark(old_entry); |
a5789b07 | 490 | mutex_unlock(&audit_tree_group->mark_mutex); |
b1e4603b | 491 | fsnotify_free_mark(old_entry); |
b3e8692b | 492 | fsnotify_put_mark(chunk_entry); /* drop initial reference */ |
28a3a7eb | 493 | fsnotify_put_mark(old_entry); /* pair to fsnotify_find mark_entry */ |
74c3cbe3 AV |
494 | return 0; |
495 | } | |
496 | ||
2991dd2b | 497 | static void audit_tree_log_remove_rule(struct audit_krule *rule) |
0644ec0c KC |
498 | { |
499 | struct audit_buffer *ab; | |
500 | ||
65a8766f RGB |
501 | if (!audit_enabled) |
502 | return; | |
0644ec0c KC |
503 | ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE); |
504 | if (unlikely(!ab)) | |
505 | return; | |
c1e8f06d | 506 | audit_log_format(ab, "op=remove_rule"); |
0644ec0c KC |
507 | audit_log_format(ab, " dir="); |
508 | audit_log_untrustedstring(ab, rule->tree->pathname); | |
509 | audit_log_key(ab, rule->filterkey); | |
510 | audit_log_format(ab, " list=%d res=1", rule->listnr); | |
511 | audit_log_end(ab); | |
512 | } | |
513 | ||
74c3cbe3 AV |
514 | static void kill_rules(struct audit_tree *tree) |
515 | { | |
516 | struct audit_krule *rule, *next; | |
517 | struct audit_entry *entry; | |
74c3cbe3 AV |
518 | |
519 | list_for_each_entry_safe(rule, next, &tree->rules, rlist) { | |
520 | entry = container_of(rule, struct audit_entry, rule); | |
521 | ||
522 | list_del_init(&rule->rlist); | |
523 | if (rule->tree) { | |
524 | /* not a half-baked one */ | |
2991dd2b | 525 | audit_tree_log_remove_rule(rule); |
34d99af5 RGB |
526 | if (entry->rule.exe) |
527 | audit_remove_mark(entry->rule.exe); | |
74c3cbe3 AV |
528 | rule->tree = NULL; |
529 | list_del_rcu(&entry->list); | |
e45aa212 | 530 | list_del(&entry->rule.list); |
74c3cbe3 AV |
531 | call_rcu(&entry->rcu, audit_free_rule_rcu); |
532 | } | |
533 | } | |
534 | } | |
535 | ||
536 | /* | |
537 | * finish killing struct audit_tree | |
538 | */ | |
539 | static void prune_one(struct audit_tree *victim) | |
540 | { | |
541 | spin_lock(&hash_lock); | |
542 | while (!list_empty(&victim->chunks)) { | |
543 | struct node *p; | |
74c3cbe3 AV |
544 | |
545 | p = list_entry(victim->chunks.next, struct node, list); | |
74c3cbe3 | 546 | |
8f7b0ba1 | 547 | untag_chunk(p); |
74c3cbe3 AV |
548 | } |
549 | spin_unlock(&hash_lock); | |
550 | put_tree(victim); | |
551 | } | |
552 | ||
553 | /* trim the uncommitted chunks from tree */ | |
554 | ||
555 | static void trim_marked(struct audit_tree *tree) | |
556 | { | |
557 | struct list_head *p, *q; | |
558 | spin_lock(&hash_lock); | |
559 | if (tree->goner) { | |
560 | spin_unlock(&hash_lock); | |
561 | return; | |
562 | } | |
563 | /* reorder */ | |
564 | for (p = tree->chunks.next; p != &tree->chunks; p = q) { | |
565 | struct node *node = list_entry(p, struct node, list); | |
566 | q = p->next; | |
567 | if (node->index & (1U<<31)) { | |
568 | list_del_init(p); | |
569 | list_add(p, &tree->chunks); | |
570 | } | |
571 | } | |
572 | ||
573 | while (!list_empty(&tree->chunks)) { | |
574 | struct node *node; | |
74c3cbe3 AV |
575 | |
576 | node = list_entry(tree->chunks.next, struct node, list); | |
577 | ||
578 | /* have we run out of marked? */ | |
579 | if (!(node->index & (1U<<31))) | |
580 | break; | |
581 | ||
8f7b0ba1 | 582 | untag_chunk(node); |
74c3cbe3 AV |
583 | } |
584 | if (!tree->root && !tree->goner) { | |
585 | tree->goner = 1; | |
586 | spin_unlock(&hash_lock); | |
587 | mutex_lock(&audit_filter_mutex); | |
588 | kill_rules(tree); | |
589 | list_del_init(&tree->list); | |
590 | mutex_unlock(&audit_filter_mutex); | |
591 | prune_one(tree); | |
592 | } else { | |
593 | spin_unlock(&hash_lock); | |
594 | } | |
595 | } | |
596 | ||
916d7576 AV |
597 | static void audit_schedule_prune(void); |
598 | ||
74c3cbe3 AV |
599 | /* called with audit_filter_mutex */ |
600 | int audit_remove_tree_rule(struct audit_krule *rule) | |
601 | { | |
602 | struct audit_tree *tree; | |
603 | tree = rule->tree; | |
604 | if (tree) { | |
605 | spin_lock(&hash_lock); | |
606 | list_del_init(&rule->rlist); | |
607 | if (list_empty(&tree->rules) && !tree->goner) { | |
608 | tree->root = NULL; | |
609 | list_del_init(&tree->same_root); | |
610 | tree->goner = 1; | |
611 | list_move(&tree->list, &prune_list); | |
612 | rule->tree = NULL; | |
613 | spin_unlock(&hash_lock); | |
614 | audit_schedule_prune(); | |
615 | return 1; | |
616 | } | |
617 | rule->tree = NULL; | |
618 | spin_unlock(&hash_lock); | |
619 | return 1; | |
620 | } | |
621 | return 0; | |
622 | } | |
623 | ||
1f707137 AV |
624 | static int compare_root(struct vfsmount *mnt, void *arg) |
625 | { | |
f410ff65 JK |
626 | return inode_to_key(d_backing_inode(mnt->mnt_root)) == |
627 | (unsigned long)arg; | |
1f707137 AV |
628 | } |
629 | ||
74c3cbe3 AV |
630 | void audit_trim_trees(void) |
631 | { | |
632 | struct list_head cursor; | |
633 | ||
634 | mutex_lock(&audit_filter_mutex); | |
635 | list_add(&cursor, &tree_list); | |
636 | while (cursor.next != &tree_list) { | |
637 | struct audit_tree *tree; | |
98bc993f | 638 | struct path path; |
74c3cbe3 AV |
639 | struct vfsmount *root_mnt; |
640 | struct node *node; | |
74c3cbe3 AV |
641 | int err; |
642 | ||
643 | tree = container_of(cursor.next, struct audit_tree, list); | |
644 | get_tree(tree); | |
645 | list_del(&cursor); | |
646 | list_add(&cursor, &tree->list); | |
647 | mutex_unlock(&audit_filter_mutex); | |
648 | ||
98bc993f | 649 | err = kern_path(tree->pathname, 0, &path); |
74c3cbe3 AV |
650 | if (err) |
651 | goto skip_it; | |
652 | ||
589ff870 | 653 | root_mnt = collect_mounts(&path); |
98bc993f | 654 | path_put(&path); |
be34d1a3 | 655 | if (IS_ERR(root_mnt)) |
74c3cbe3 AV |
656 | goto skip_it; |
657 | ||
74c3cbe3 AV |
658 | spin_lock(&hash_lock); |
659 | list_for_each_entry(node, &tree->chunks, list) { | |
28a3a7eb | 660 | struct audit_chunk *chunk = find_chunk(node); |
25985edc | 661 | /* this could be NULL if the watch is dying else where... */ |
74c3cbe3 | 662 | node->index |= 1U<<31; |
f410ff65 | 663 | if (iterate_mounts(compare_root, |
8d20d6e9 | 664 | (void *)(chunk->key), |
f410ff65 | 665 | root_mnt)) |
1f707137 | 666 | node->index &= ~(1U<<31); |
74c3cbe3 AV |
667 | } |
668 | spin_unlock(&hash_lock); | |
669 | trim_marked(tree); | |
74c3cbe3 AV |
670 | drop_collected_mounts(root_mnt); |
671 | skip_it: | |
12b2f117 | 672 | put_tree(tree); |
74c3cbe3 AV |
673 | mutex_lock(&audit_filter_mutex); |
674 | } | |
675 | list_del(&cursor); | |
676 | mutex_unlock(&audit_filter_mutex); | |
677 | } | |
678 | ||
74c3cbe3 AV |
679 | int audit_make_tree(struct audit_krule *rule, char *pathname, u32 op) |
680 | { | |
681 | ||
682 | if (pathname[0] != '/' || | |
683 | rule->listnr != AUDIT_FILTER_EXIT || | |
5af75d8d | 684 | op != Audit_equal || |
74c3cbe3 AV |
685 | rule->inode_f || rule->watch || rule->tree) |
686 | return -EINVAL; | |
687 | rule->tree = alloc_tree(pathname); | |
688 | if (!rule->tree) | |
689 | return -ENOMEM; | |
690 | return 0; | |
691 | } | |
692 | ||
693 | void audit_put_tree(struct audit_tree *tree) | |
694 | { | |
695 | put_tree(tree); | |
696 | } | |
697 | ||
1f707137 AV |
698 | static int tag_mount(struct vfsmount *mnt, void *arg) |
699 | { | |
3b362157 | 700 | return tag_chunk(d_backing_inode(mnt->mnt_root), arg); |
1f707137 AV |
701 | } |
702 | ||
f1aaf262 IP |
703 | /* |
704 | * That gets run when evict_chunk() ends up needing to kill audit_tree. | |
705 | * Runs from a separate thread. | |
706 | */ | |
707 | static int prune_tree_thread(void *unused) | |
708 | { | |
709 | for (;;) { | |
0bf676d1 JS |
710 | if (list_empty(&prune_list)) { |
711 | set_current_state(TASK_INTERRUPTIBLE); | |
f1aaf262 | 712 | schedule(); |
0bf676d1 | 713 | } |
f1aaf262 | 714 | |
ce423631 | 715 | audit_ctl_lock(); |
f1aaf262 IP |
716 | mutex_lock(&audit_filter_mutex); |
717 | ||
718 | while (!list_empty(&prune_list)) { | |
719 | struct audit_tree *victim; | |
720 | ||
721 | victim = list_entry(prune_list.next, | |
722 | struct audit_tree, list); | |
723 | list_del_init(&victim->list); | |
724 | ||
725 | mutex_unlock(&audit_filter_mutex); | |
726 | ||
727 | prune_one(victim); | |
728 | ||
729 | mutex_lock(&audit_filter_mutex); | |
730 | } | |
731 | ||
732 | mutex_unlock(&audit_filter_mutex); | |
ce423631 | 733 | audit_ctl_unlock(); |
f1aaf262 IP |
734 | } |
735 | return 0; | |
736 | } | |
737 | ||
738 | static int audit_launch_prune(void) | |
739 | { | |
740 | if (prune_thread) | |
741 | return 0; | |
0bf676d1 | 742 | prune_thread = kthread_run(prune_tree_thread, NULL, |
f1aaf262 IP |
743 | "audit_prune_tree"); |
744 | if (IS_ERR(prune_thread)) { | |
745 | pr_err("cannot start thread audit_prune_tree"); | |
746 | prune_thread = NULL; | |
747 | return -ENOMEM; | |
f1aaf262 | 748 | } |
0bf676d1 | 749 | return 0; |
f1aaf262 IP |
750 | } |
751 | ||
74c3cbe3 AV |
752 | /* called with audit_filter_mutex */ |
753 | int audit_add_tree_rule(struct audit_krule *rule) | |
754 | { | |
755 | struct audit_tree *seed = rule->tree, *tree; | |
98bc993f | 756 | struct path path; |
1f707137 | 757 | struct vfsmount *mnt; |
74c3cbe3 AV |
758 | int err; |
759 | ||
736f3203 | 760 | rule->tree = NULL; |
74c3cbe3 AV |
761 | list_for_each_entry(tree, &tree_list, list) { |
762 | if (!strcmp(seed->pathname, tree->pathname)) { | |
763 | put_tree(seed); | |
764 | rule->tree = tree; | |
765 | list_add(&rule->rlist, &tree->rules); | |
766 | return 0; | |
767 | } | |
768 | } | |
769 | tree = seed; | |
770 | list_add(&tree->list, &tree_list); | |
771 | list_add(&rule->rlist, &tree->rules); | |
772 | /* do not set rule->tree yet */ | |
773 | mutex_unlock(&audit_filter_mutex); | |
774 | ||
f1aaf262 IP |
775 | if (unlikely(!prune_thread)) { |
776 | err = audit_launch_prune(); | |
777 | if (err) | |
778 | goto Err; | |
779 | } | |
780 | ||
98bc993f | 781 | err = kern_path(tree->pathname, 0, &path); |
74c3cbe3 AV |
782 | if (err) |
783 | goto Err; | |
589ff870 | 784 | mnt = collect_mounts(&path); |
98bc993f | 785 | path_put(&path); |
be34d1a3 DH |
786 | if (IS_ERR(mnt)) { |
787 | err = PTR_ERR(mnt); | |
74c3cbe3 AV |
788 | goto Err; |
789 | } | |
74c3cbe3 AV |
790 | |
791 | get_tree(tree); | |
1f707137 | 792 | err = iterate_mounts(tag_mount, tree, mnt); |
74c3cbe3 AV |
793 | drop_collected_mounts(mnt); |
794 | ||
795 | if (!err) { | |
796 | struct node *node; | |
797 | spin_lock(&hash_lock); | |
798 | list_for_each_entry(node, &tree->chunks, list) | |
799 | node->index &= ~(1U<<31); | |
800 | spin_unlock(&hash_lock); | |
801 | } else { | |
802 | trim_marked(tree); | |
803 | goto Err; | |
804 | } | |
805 | ||
806 | mutex_lock(&audit_filter_mutex); | |
807 | if (list_empty(&rule->rlist)) { | |
808 | put_tree(tree); | |
809 | return -ENOENT; | |
810 | } | |
811 | rule->tree = tree; | |
812 | put_tree(tree); | |
813 | ||
814 | return 0; | |
815 | Err: | |
816 | mutex_lock(&audit_filter_mutex); | |
817 | list_del_init(&tree->list); | |
818 | list_del_init(&tree->rules); | |
819 | put_tree(tree); | |
820 | return err; | |
821 | } | |
822 | ||
823 | int audit_tag_tree(char *old, char *new) | |
824 | { | |
825 | struct list_head cursor, barrier; | |
826 | int failed = 0; | |
2096f759 | 827 | struct path path1, path2; |
74c3cbe3 | 828 | struct vfsmount *tagged; |
74c3cbe3 AV |
829 | int err; |
830 | ||
2096f759 | 831 | err = kern_path(new, 0, &path2); |
74c3cbe3 AV |
832 | if (err) |
833 | return err; | |
2096f759 AV |
834 | tagged = collect_mounts(&path2); |
835 | path_put(&path2); | |
be34d1a3 DH |
836 | if (IS_ERR(tagged)) |
837 | return PTR_ERR(tagged); | |
74c3cbe3 | 838 | |
2096f759 | 839 | err = kern_path(old, 0, &path1); |
74c3cbe3 AV |
840 | if (err) { |
841 | drop_collected_mounts(tagged); | |
842 | return err; | |
843 | } | |
74c3cbe3 | 844 | |
74c3cbe3 AV |
845 | mutex_lock(&audit_filter_mutex); |
846 | list_add(&barrier, &tree_list); | |
847 | list_add(&cursor, &barrier); | |
848 | ||
849 | while (cursor.next != &tree_list) { | |
850 | struct audit_tree *tree; | |
2096f759 | 851 | int good_one = 0; |
74c3cbe3 AV |
852 | |
853 | tree = container_of(cursor.next, struct audit_tree, list); | |
854 | get_tree(tree); | |
855 | list_del(&cursor); | |
856 | list_add(&cursor, &tree->list); | |
857 | mutex_unlock(&audit_filter_mutex); | |
858 | ||
2096f759 AV |
859 | err = kern_path(tree->pathname, 0, &path2); |
860 | if (!err) { | |
861 | good_one = path_is_under(&path1, &path2); | |
862 | path_put(&path2); | |
74c3cbe3 AV |
863 | } |
864 | ||
2096f759 | 865 | if (!good_one) { |
74c3cbe3 AV |
866 | put_tree(tree); |
867 | mutex_lock(&audit_filter_mutex); | |
868 | continue; | |
869 | } | |
74c3cbe3 | 870 | |
1f707137 | 871 | failed = iterate_mounts(tag_mount, tree, tagged); |
74c3cbe3 AV |
872 | if (failed) { |
873 | put_tree(tree); | |
874 | mutex_lock(&audit_filter_mutex); | |
875 | break; | |
876 | } | |
877 | ||
878 | mutex_lock(&audit_filter_mutex); | |
879 | spin_lock(&hash_lock); | |
880 | if (!tree->goner) { | |
881 | list_del(&tree->list); | |
882 | list_add(&tree->list, &tree_list); | |
883 | } | |
884 | spin_unlock(&hash_lock); | |
885 | put_tree(tree); | |
886 | } | |
887 | ||
888 | while (barrier.prev != &tree_list) { | |
889 | struct audit_tree *tree; | |
890 | ||
891 | tree = container_of(barrier.prev, struct audit_tree, list); | |
892 | get_tree(tree); | |
893 | list_del(&tree->list); | |
894 | list_add(&tree->list, &barrier); | |
895 | mutex_unlock(&audit_filter_mutex); | |
896 | ||
897 | if (!failed) { | |
898 | struct node *node; | |
899 | spin_lock(&hash_lock); | |
900 | list_for_each_entry(node, &tree->chunks, list) | |
901 | node->index &= ~(1U<<31); | |
902 | spin_unlock(&hash_lock); | |
903 | } else { | |
904 | trim_marked(tree); | |
905 | } | |
906 | ||
907 | put_tree(tree); | |
908 | mutex_lock(&audit_filter_mutex); | |
909 | } | |
910 | list_del(&barrier); | |
911 | list_del(&cursor); | |
74c3cbe3 | 912 | mutex_unlock(&audit_filter_mutex); |
2096f759 | 913 | path_put(&path1); |
74c3cbe3 AV |
914 | drop_collected_mounts(tagged); |
915 | return failed; | |
916 | } | |
917 | ||
916d7576 AV |
918 | |
919 | static void audit_schedule_prune(void) | |
920 | { | |
f1aaf262 | 921 | wake_up_process(prune_thread); |
916d7576 AV |
922 | } |
923 | ||
924 | /* | |
925 | * ... and that one is done if evict_chunk() decides to delay until the end | |
926 | * of syscall. Runs synchronously. | |
927 | */ | |
928 | void audit_kill_trees(struct list_head *list) | |
929 | { | |
ce423631 | 930 | audit_ctl_lock(); |
916d7576 AV |
931 | mutex_lock(&audit_filter_mutex); |
932 | ||
933 | while (!list_empty(list)) { | |
934 | struct audit_tree *victim; | |
935 | ||
936 | victim = list_entry(list->next, struct audit_tree, list); | |
937 | kill_rules(victim); | |
938 | list_del_init(&victim->list); | |
939 | ||
940 | mutex_unlock(&audit_filter_mutex); | |
941 | ||
942 | prune_one(victim); | |
943 | ||
944 | mutex_lock(&audit_filter_mutex); | |
945 | } | |
946 | ||
947 | mutex_unlock(&audit_filter_mutex); | |
ce423631 | 948 | audit_ctl_unlock(); |
74c3cbe3 AV |
949 | } |
950 | ||
951 | /* | |
952 | * Here comes the stuff asynchronous to auditctl operations | |
953 | */ | |
954 | ||
74c3cbe3 AV |
955 | static void evict_chunk(struct audit_chunk *chunk) |
956 | { | |
957 | struct audit_tree *owner; | |
916d7576 AV |
958 | struct list_head *postponed = audit_killed_trees(); |
959 | int need_prune = 0; | |
74c3cbe3 AV |
960 | int n; |
961 | ||
962 | if (chunk->dead) | |
963 | return; | |
964 | ||
965 | chunk->dead = 1; | |
966 | mutex_lock(&audit_filter_mutex); | |
967 | spin_lock(&hash_lock); | |
968 | while (!list_empty(&chunk->trees)) { | |
969 | owner = list_entry(chunk->trees.next, | |
970 | struct audit_tree, same_root); | |
971 | owner->goner = 1; | |
972 | owner->root = NULL; | |
973 | list_del_init(&owner->same_root); | |
974 | spin_unlock(&hash_lock); | |
916d7576 AV |
975 | if (!postponed) { |
976 | kill_rules(owner); | |
977 | list_move(&owner->list, &prune_list); | |
978 | need_prune = 1; | |
979 | } else { | |
980 | list_move(&owner->list, postponed); | |
981 | } | |
74c3cbe3 AV |
982 | spin_lock(&hash_lock); |
983 | } | |
984 | list_del_rcu(&chunk->hash); | |
985 | for (n = 0; n < chunk->count; n++) | |
986 | list_del_init(&chunk->owners[n].list); | |
987 | spin_unlock(&hash_lock); | |
f1aaf262 | 988 | mutex_unlock(&audit_filter_mutex); |
916d7576 AV |
989 | if (need_prune) |
990 | audit_schedule_prune(); | |
74c3cbe3 AV |
991 | } |
992 | ||
3a9b16b4 | 993 | static int audit_tree_handle_event(struct fsnotify_group *group, |
7053aee2 | 994 | struct inode *to_tell, |
3cd5eca8 | 995 | u32 mask, const void *data, int data_type, |
9385a84d JK |
996 | const unsigned char *file_name, u32 cookie, |
997 | struct fsnotify_iter_info *iter_info) | |
74c3cbe3 | 998 | { |
83c4c4b0 | 999 | return 0; |
28a3a7eb | 1000 | } |
74c3cbe3 | 1001 | |
e61ce867 | 1002 | static void audit_tree_freeing_mark(struct fsnotify_mark *entry, struct fsnotify_group *group) |
28a3a7eb EP |
1003 | { |
1004 | struct audit_chunk *chunk = container_of(entry, struct audit_chunk, mark); | |
1005 | ||
1006 | evict_chunk(chunk); | |
b3e8692b MS |
1007 | |
1008 | /* | |
1009 | * We are guaranteed to have at least one reference to the mark from | |
1010 | * either the inode or the caller of fsnotify_destroy_mark(). | |
1011 | */ | |
ab97f873 | 1012 | BUG_ON(refcount_read(&entry->refcnt) < 1); |
74c3cbe3 AV |
1013 | } |
1014 | ||
28a3a7eb EP |
1015 | static const struct fsnotify_ops audit_tree_ops = { |
1016 | .handle_event = audit_tree_handle_event, | |
28a3a7eb | 1017 | .freeing_mark = audit_tree_freeing_mark, |
054c636e | 1018 | .free_mark = audit_tree_destroy_watch, |
74c3cbe3 AV |
1019 | }; |
1020 | ||
1021 | static int __init audit_tree_init(void) | |
1022 | { | |
1023 | int i; | |
1024 | ||
0d2e2a1d | 1025 | audit_tree_group = fsnotify_alloc_group(&audit_tree_ops); |
28a3a7eb EP |
1026 | if (IS_ERR(audit_tree_group)) |
1027 | audit_panic("cannot initialize fsnotify group for rectree watches"); | |
74c3cbe3 AV |
1028 | |
1029 | for (i = 0; i < HASH_SIZE; i++) | |
1030 | INIT_LIST_HEAD(&chunk_hash_heads[i]); | |
1031 | ||
1032 | return 0; | |
1033 | } | |
1034 | __initcall(audit_tree_init); |