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Al Viro74c3cbe2007-07-22 08:04:18 -04001#include "audit.h"
2#include <linux/inotify.h>
3#include <linux/namei.h>
4#include <linux/mount.h>
Al Viro916d7572009-06-24 00:02:38 -04005#include <linux/kthread.h>
Al Viro74c3cbe2007-07-22 08:04:18 -04006
7struct audit_tree;
8struct audit_chunk;
9
10struct audit_tree {
11 atomic_t count;
12 int goner;
13 struct audit_chunk *root;
14 struct list_head chunks;
15 struct list_head rules;
16 struct list_head list;
17 struct list_head same_root;
18 struct rcu_head head;
19 char pathname[];
20};
21
22struct audit_chunk {
23 struct list_head hash;
24 struct inotify_watch watch;
25 struct list_head trees; /* with root here */
26 int dead;
27 int count;
Al Viro8f7b0ba2008-11-15 01:15:43 +000028 atomic_long_t refs;
Al Viro74c3cbe2007-07-22 08:04:18 -040029 struct rcu_head head;
30 struct node {
31 struct list_head list;
32 struct audit_tree *owner;
33 unsigned index; /* index; upper bit indicates 'will prune' */
34 } owners[];
35};
36
37static LIST_HEAD(tree_list);
38static LIST_HEAD(prune_list);
39
40/*
41 * One struct chunk is attached to each inode of interest.
42 * We replace struct chunk on tagging/untagging.
43 * Rules have pointer to struct audit_tree.
44 * Rules have struct list_head rlist forming a list of rules over
45 * the same tree.
46 * References to struct chunk are collected at audit_inode{,_child}()
47 * time and used in AUDIT_TREE rule matching.
48 * These references are dropped at the same time we are calling
49 * audit_free_names(), etc.
50 *
51 * Cyclic lists galore:
52 * tree.chunks anchors chunk.owners[].list hash_lock
53 * tree.rules anchors rule.rlist audit_filter_mutex
54 * chunk.trees anchors tree.same_root hash_lock
55 * chunk.hash is a hash with middle bits of watch.inode as
56 * a hash function. RCU, hash_lock
57 *
58 * tree is refcounted; one reference for "some rules on rules_list refer to
59 * it", one for each chunk with pointer to it.
60 *
Al Viro8f7b0ba2008-11-15 01:15:43 +000061 * chunk is refcounted by embedded inotify_watch + .refs (non-zero refcount
62 * of watch contributes 1 to .refs).
Al Viro74c3cbe2007-07-22 08:04:18 -040063 *
64 * node.index allows to get from node.list to containing chunk.
65 * MSB of that sucker is stolen to mark taggings that we might have to
66 * revert - several operations have very unpleasant cleanup logics and
67 * that makes a difference. Some.
68 */
69
70static struct inotify_handle *rtree_ih;
71
72static struct audit_tree *alloc_tree(const char *s)
73{
74 struct audit_tree *tree;
75
76 tree = kmalloc(sizeof(struct audit_tree) + strlen(s) + 1, GFP_KERNEL);
77 if (tree) {
78 atomic_set(&tree->count, 1);
79 tree->goner = 0;
80 INIT_LIST_HEAD(&tree->chunks);
81 INIT_LIST_HEAD(&tree->rules);
82 INIT_LIST_HEAD(&tree->list);
83 INIT_LIST_HEAD(&tree->same_root);
84 tree->root = NULL;
85 strcpy(tree->pathname, s);
86 }
87 return tree;
88}
89
90static inline void get_tree(struct audit_tree *tree)
91{
92 atomic_inc(&tree->count);
93}
94
95static void __put_tree(struct rcu_head *rcu)
96{
97 struct audit_tree *tree = container_of(rcu, struct audit_tree, head);
98 kfree(tree);
99}
100
101static inline void put_tree(struct audit_tree *tree)
102{
103 if (atomic_dec_and_test(&tree->count))
104 call_rcu(&tree->head, __put_tree);
105}
106
107/* to avoid bringing the entire thing in audit.h */
108const char *audit_tree_path(struct audit_tree *tree)
109{
110 return tree->pathname;
111}
112
113static struct audit_chunk *alloc_chunk(int count)
114{
115 struct audit_chunk *chunk;
116 size_t size;
117 int i;
118
119 size = offsetof(struct audit_chunk, owners) + count * sizeof(struct node);
120 chunk = kzalloc(size, GFP_KERNEL);
121 if (!chunk)
122 return NULL;
123
124 INIT_LIST_HEAD(&chunk->hash);
125 INIT_LIST_HEAD(&chunk->trees);
126 chunk->count = count;
Al Viro8f7b0ba2008-11-15 01:15:43 +0000127 atomic_long_set(&chunk->refs, 1);
Al Viro74c3cbe2007-07-22 08:04:18 -0400128 for (i = 0; i < count; i++) {
129 INIT_LIST_HEAD(&chunk->owners[i].list);
130 chunk->owners[i].index = i;
131 }
132 inotify_init_watch(&chunk->watch);
133 return chunk;
134}
135
Al Viro8f7b0ba2008-11-15 01:15:43 +0000136static void free_chunk(struct audit_chunk *chunk)
Al Viro74c3cbe2007-07-22 08:04:18 -0400137{
Al Viro74c3cbe2007-07-22 08:04:18 -0400138 int i;
139
140 for (i = 0; i < chunk->count; i++) {
141 if (chunk->owners[i].owner)
142 put_tree(chunk->owners[i].owner);
143 }
144 kfree(chunk);
145}
146
Al Viro74c3cbe2007-07-22 08:04:18 -0400147void audit_put_chunk(struct audit_chunk *chunk)
148{
Al Viro8f7b0ba2008-11-15 01:15:43 +0000149 if (atomic_long_dec_and_test(&chunk->refs))
150 free_chunk(chunk);
151}
152
153static void __put_chunk(struct rcu_head *rcu)
154{
155 struct audit_chunk *chunk = container_of(rcu, struct audit_chunk, head);
156 audit_put_chunk(chunk);
Al Viro74c3cbe2007-07-22 08:04:18 -0400157}
158
159enum {HASH_SIZE = 128};
160static struct list_head chunk_hash_heads[HASH_SIZE];
161static __cacheline_aligned_in_smp DEFINE_SPINLOCK(hash_lock);
162
163static inline struct list_head *chunk_hash(const struct inode *inode)
164{
165 unsigned long n = (unsigned long)inode / L1_CACHE_BYTES;
166 return chunk_hash_heads + n % HASH_SIZE;
167}
168
169/* hash_lock is held by caller */
170static void insert_hash(struct audit_chunk *chunk)
171{
172 struct list_head *list = chunk_hash(chunk->watch.inode);
173 list_add_rcu(&chunk->hash, list);
174}
175
176/* called under rcu_read_lock */
177struct audit_chunk *audit_tree_lookup(const struct inode *inode)
178{
179 struct list_head *list = chunk_hash(inode);
Paul E. McKenney6793a052008-05-14 17:10:12 -0700180 struct audit_chunk *p;
Al Viro74c3cbe2007-07-22 08:04:18 -0400181
Paul E. McKenney6793a052008-05-14 17:10:12 -0700182 list_for_each_entry_rcu(p, list, hash) {
Al Viro74c3cbe2007-07-22 08:04:18 -0400183 if (p->watch.inode == inode) {
Al Viro8f7b0ba2008-11-15 01:15:43 +0000184 atomic_long_inc(&p->refs);
Al Viro74c3cbe2007-07-22 08:04:18 -0400185 return p;
186 }
187 }
188 return NULL;
189}
190
191int audit_tree_match(struct audit_chunk *chunk, struct audit_tree *tree)
192{
193 int n;
194 for (n = 0; n < chunk->count; n++)
195 if (chunk->owners[n].owner == tree)
196 return 1;
197 return 0;
198}
199
200/* tagging and untagging inodes with trees */
201
Al Viro8f7b0ba2008-11-15 01:15:43 +0000202static struct audit_chunk *find_chunk(struct node *p)
Al Viro74c3cbe2007-07-22 08:04:18 -0400203{
Al Viro8f7b0ba2008-11-15 01:15:43 +0000204 int index = p->index & ~(1U<<31);
205 p -= index;
206 return container_of(p, struct audit_chunk, owners[0]);
207}
208
209static void untag_chunk(struct node *p)
210{
211 struct audit_chunk *chunk = find_chunk(p);
Al Viro74c3cbe2007-07-22 08:04:18 -0400212 struct audit_chunk *new;
213 struct audit_tree *owner;
214 int size = chunk->count - 1;
215 int i, j;
216
Al Viro8f7b0ba2008-11-15 01:15:43 +0000217 if (!pin_inotify_watch(&chunk->watch)) {
218 /*
219 * Filesystem is shutting down; all watches are getting
220 * evicted, just take it off the node list for this
221 * tree and let the eviction logics take care of the
222 * rest.
223 */
224 owner = p->owner;
225 if (owner->root == chunk) {
226 list_del_init(&owner->same_root);
227 owner->root = NULL;
228 }
229 list_del_init(&p->list);
230 p->owner = NULL;
231 put_tree(owner);
232 return;
233 }
234
235 spin_unlock(&hash_lock);
236
237 /*
238 * pin_inotify_watch() succeeded, so the watch won't go away
239 * from under us.
240 */
Al Viro74c3cbe2007-07-22 08:04:18 -0400241 mutex_lock(&chunk->watch.inode->inotify_mutex);
242 if (chunk->dead) {
243 mutex_unlock(&chunk->watch.inode->inotify_mutex);
Al Viro8f7b0ba2008-11-15 01:15:43 +0000244 goto out;
Al Viro74c3cbe2007-07-22 08:04:18 -0400245 }
246
247 owner = p->owner;
248
249 if (!size) {
250 chunk->dead = 1;
251 spin_lock(&hash_lock);
252 list_del_init(&chunk->trees);
253 if (owner->root == chunk)
254 owner->root = NULL;
255 list_del_init(&p->list);
256 list_del_rcu(&chunk->hash);
257 spin_unlock(&hash_lock);
258 inotify_evict_watch(&chunk->watch);
259 mutex_unlock(&chunk->watch.inode->inotify_mutex);
260 put_inotify_watch(&chunk->watch);
Al Viro8f7b0ba2008-11-15 01:15:43 +0000261 goto out;
Al Viro74c3cbe2007-07-22 08:04:18 -0400262 }
263
264 new = alloc_chunk(size);
265 if (!new)
266 goto Fallback;
267 if (inotify_clone_watch(&chunk->watch, &new->watch) < 0) {
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; i < 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[i].list, &new->owners[j].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 inotify_evict_watch(&chunk->watch);
301 mutex_unlock(&chunk->watch.inode->inotify_mutex);
302 put_inotify_watch(&chunk->watch);
Al Viro8f7b0ba2008-11-15 01:15:43 +0000303 goto out;
Al Viro74c3cbe2007-07-22 08:04:18 -0400304
305Fallback:
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 mutex_unlock(&chunk->watch.inode->inotify_mutex);
Al Viro8f7b0ba2008-11-15 01:15:43 +0000317out:
318 unpin_inotify_watch(&chunk->watch);
319 spin_lock(&hash_lock);
Al Viro74c3cbe2007-07-22 08:04:18 -0400320}
321
322static int create_chunk(struct inode *inode, struct audit_tree *tree)
323{
324 struct audit_chunk *chunk = alloc_chunk(1);
325 if (!chunk)
326 return -ENOMEM;
327
328 if (inotify_add_watch(rtree_ih, &chunk->watch, inode, IN_IGNORED | IN_DELETE_SELF) < 0) {
329 free_chunk(chunk);
330 return -ENOSPC;
331 }
332
333 mutex_lock(&inode->inotify_mutex);
334 spin_lock(&hash_lock);
335 if (tree->goner) {
336 spin_unlock(&hash_lock);
337 chunk->dead = 1;
338 inotify_evict_watch(&chunk->watch);
339 mutex_unlock(&inode->inotify_mutex);
340 put_inotify_watch(&chunk->watch);
341 return 0;
342 }
343 chunk->owners[0].index = (1U << 31);
344 chunk->owners[0].owner = tree;
345 get_tree(tree);
346 list_add(&chunk->owners[0].list, &tree->chunks);
347 if (!tree->root) {
348 tree->root = chunk;
349 list_add(&tree->same_root, &chunk->trees);
350 }
351 insert_hash(chunk);
352 spin_unlock(&hash_lock);
353 mutex_unlock(&inode->inotify_mutex);
354 return 0;
355}
356
357/* the first tagged inode becomes root of tree */
358static int tag_chunk(struct inode *inode, struct audit_tree *tree)
359{
360 struct inotify_watch *watch;
361 struct audit_tree *owner;
362 struct audit_chunk *chunk, *old;
363 struct node *p;
364 int n;
365
366 if (inotify_find_watch(rtree_ih, inode, &watch) < 0)
367 return create_chunk(inode, tree);
368
369 old = container_of(watch, struct audit_chunk, watch);
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);
376 put_inotify_watch(watch);
377 return 0;
378 }
379 }
380 spin_unlock(&hash_lock);
381
382 chunk = alloc_chunk(old->count + 1);
383 if (!chunk)
384 return -ENOMEM;
385
386 mutex_lock(&inode->inotify_mutex);
387 if (inotify_clone_watch(&old->watch, &chunk->watch) < 0) {
388 mutex_unlock(&inode->inotify_mutex);
Eric Paris318b6d32009-01-13 17:32:40 -0500389 put_inotify_watch(&old->watch);
Al Viro74c3cbe2007-07-22 08:04:18 -0400390 free_chunk(chunk);
391 return -ENOSPC;
392 }
393 spin_lock(&hash_lock);
394 if (tree->goner) {
395 spin_unlock(&hash_lock);
396 chunk->dead = 1;
397 inotify_evict_watch(&chunk->watch);
398 mutex_unlock(&inode->inotify_mutex);
Eric Paris318b6d32009-01-13 17:32:40 -0500399 put_inotify_watch(&old->watch);
Al Viro74c3cbe2007-07-22 08:04:18 -0400400 put_inotify_watch(&chunk->watch);
401 return 0;
402 }
403 list_replace_init(&old->trees, &chunk->trees);
404 for (n = 0, p = chunk->owners; n < old->count; n++, p++) {
405 struct audit_tree *s = old->owners[n].owner;
406 p->owner = s;
407 p->index = old->owners[n].index;
408 if (!s) /* result of fallback in untag */
409 continue;
410 get_tree(s);
411 list_replace_init(&old->owners[n].list, &p->list);
412 }
413 p->index = (chunk->count - 1) | (1U<<31);
414 p->owner = tree;
415 get_tree(tree);
416 list_add(&p->list, &tree->chunks);
417 list_replace_rcu(&old->hash, &chunk->hash);
418 list_for_each_entry(owner, &chunk->trees, same_root)
419 owner->root = chunk;
420 old->dead = 1;
421 if (!tree->root) {
422 tree->root = chunk;
423 list_add(&tree->same_root, &chunk->trees);
424 }
425 spin_unlock(&hash_lock);
426 inotify_evict_watch(&old->watch);
427 mutex_unlock(&inode->inotify_mutex);
428 put_inotify_watch(&old->watch);
429 return 0;
430}
431
Al Viro74c3cbe2007-07-22 08:04:18 -0400432static void kill_rules(struct audit_tree *tree)
433{
434 struct audit_krule *rule, *next;
435 struct audit_entry *entry;
436 struct audit_buffer *ab;
437
438 list_for_each_entry_safe(rule, next, &tree->rules, rlist) {
439 entry = container_of(rule, struct audit_entry, rule);
440
441 list_del_init(&rule->rlist);
442 if (rule->tree) {
443 /* not a half-baked one */
444 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
Eric Paris9d960982009-06-11 14:31:37 -0400445 audit_log_format(ab, "op=");
446 audit_log_string(ab, "remove rule");
447 audit_log_format(ab, " dir=");
Al Viro74c3cbe2007-07-22 08:04:18 -0400448 audit_log_untrustedstring(ab, rule->tree->pathname);
Eric Paris9d960982009-06-11 14:31:37 -0400449 audit_log_key(ab, rule->filterkey);
Al Viro74c3cbe2007-07-22 08:04:18 -0400450 audit_log_format(ab, " list=%d res=1", rule->listnr);
451 audit_log_end(ab);
452 rule->tree = NULL;
453 list_del_rcu(&entry->list);
Al Viroe45aa212008-12-15 01:17:50 -0500454 list_del(&entry->rule.list);
Al Viro74c3cbe2007-07-22 08:04:18 -0400455 call_rcu(&entry->rcu, audit_free_rule_rcu);
456 }
457 }
458}
459
460/*
461 * finish killing struct audit_tree
462 */
463static void prune_one(struct audit_tree *victim)
464{
465 spin_lock(&hash_lock);
466 while (!list_empty(&victim->chunks)) {
467 struct node *p;
Al Viro74c3cbe2007-07-22 08:04:18 -0400468
469 p = list_entry(victim->chunks.next, struct node, list);
Al Viro74c3cbe2007-07-22 08:04:18 -0400470
Al Viro8f7b0ba2008-11-15 01:15:43 +0000471 untag_chunk(p);
Al Viro74c3cbe2007-07-22 08:04:18 -0400472 }
473 spin_unlock(&hash_lock);
474 put_tree(victim);
475}
476
477/* trim the uncommitted chunks from tree */
478
479static void trim_marked(struct audit_tree *tree)
480{
481 struct list_head *p, *q;
482 spin_lock(&hash_lock);
483 if (tree->goner) {
484 spin_unlock(&hash_lock);
485 return;
486 }
487 /* reorder */
488 for (p = tree->chunks.next; p != &tree->chunks; p = q) {
489 struct node *node = list_entry(p, struct node, list);
490 q = p->next;
491 if (node->index & (1U<<31)) {
492 list_del_init(p);
493 list_add(p, &tree->chunks);
494 }
495 }
496
497 while (!list_empty(&tree->chunks)) {
498 struct node *node;
Al Viro74c3cbe2007-07-22 08:04:18 -0400499
500 node = list_entry(tree->chunks.next, struct node, list);
501
502 /* have we run out of marked? */
503 if (!(node->index & (1U<<31)))
504 break;
505
Al Viro8f7b0ba2008-11-15 01:15:43 +0000506 untag_chunk(node);
Al Viro74c3cbe2007-07-22 08:04:18 -0400507 }
508 if (!tree->root && !tree->goner) {
509 tree->goner = 1;
510 spin_unlock(&hash_lock);
511 mutex_lock(&audit_filter_mutex);
512 kill_rules(tree);
513 list_del_init(&tree->list);
514 mutex_unlock(&audit_filter_mutex);
515 prune_one(tree);
516 } else {
517 spin_unlock(&hash_lock);
518 }
519}
520
Al Viro916d7572009-06-24 00:02:38 -0400521static void audit_schedule_prune(void);
522
Al Viro74c3cbe2007-07-22 08:04:18 -0400523/* called with audit_filter_mutex */
524int audit_remove_tree_rule(struct audit_krule *rule)
525{
526 struct audit_tree *tree;
527 tree = rule->tree;
528 if (tree) {
529 spin_lock(&hash_lock);
530 list_del_init(&rule->rlist);
531 if (list_empty(&tree->rules) && !tree->goner) {
532 tree->root = NULL;
533 list_del_init(&tree->same_root);
534 tree->goner = 1;
535 list_move(&tree->list, &prune_list);
536 rule->tree = NULL;
537 spin_unlock(&hash_lock);
538 audit_schedule_prune();
539 return 1;
540 }
541 rule->tree = NULL;
542 spin_unlock(&hash_lock);
543 return 1;
544 }
545 return 0;
546}
547
548void audit_trim_trees(void)
549{
550 struct list_head cursor;
551
552 mutex_lock(&audit_filter_mutex);
553 list_add(&cursor, &tree_list);
554 while (cursor.next != &tree_list) {
555 struct audit_tree *tree;
Al Viro98bc9932008-08-02 01:06:21 -0400556 struct path path;
Al Viro74c3cbe2007-07-22 08:04:18 -0400557 struct vfsmount *root_mnt;
558 struct node *node;
559 struct list_head list;
560 int err;
561
562 tree = container_of(cursor.next, struct audit_tree, list);
563 get_tree(tree);
564 list_del(&cursor);
565 list_add(&cursor, &tree->list);
566 mutex_unlock(&audit_filter_mutex);
567
Al Viro98bc9932008-08-02 01:06:21 -0400568 err = kern_path(tree->pathname, 0, &path);
Al Viro74c3cbe2007-07-22 08:04:18 -0400569 if (err)
570 goto skip_it;
571
Al Viro589ff872009-04-18 03:28:19 -0400572 root_mnt = collect_mounts(&path);
Al Viro98bc9932008-08-02 01:06:21 -0400573 path_put(&path);
Al Viro74c3cbe2007-07-22 08:04:18 -0400574 if (!root_mnt)
575 goto skip_it;
576
577 list_add_tail(&list, &root_mnt->mnt_list);
578 spin_lock(&hash_lock);
579 list_for_each_entry(node, &tree->chunks, list) {
580 struct audit_chunk *chunk = find_chunk(node);
581 struct inode *inode = chunk->watch.inode;
582 struct vfsmount *mnt;
583 node->index |= 1U<<31;
584 list_for_each_entry(mnt, &list, mnt_list) {
585 if (mnt->mnt_root->d_inode == inode) {
586 node->index &= ~(1U<<31);
587 break;
588 }
589 }
590 }
591 spin_unlock(&hash_lock);
592 trim_marked(tree);
593 put_tree(tree);
594 list_del_init(&list);
595 drop_collected_mounts(root_mnt);
596skip_it:
597 mutex_lock(&audit_filter_mutex);
598 }
599 list_del(&cursor);
600 mutex_unlock(&audit_filter_mutex);
601}
602
603static int is_under(struct vfsmount *mnt, struct dentry *dentry,
Al Viro98bc9932008-08-02 01:06:21 -0400604 struct path *path)
Al Viro74c3cbe2007-07-22 08:04:18 -0400605{
Al Viro98bc9932008-08-02 01:06:21 -0400606 if (mnt != path->mnt) {
Al Viro74c3cbe2007-07-22 08:04:18 -0400607 for (;;) {
608 if (mnt->mnt_parent == mnt)
609 return 0;
Al Viro98bc9932008-08-02 01:06:21 -0400610 if (mnt->mnt_parent == path->mnt)
Al Viro74c3cbe2007-07-22 08:04:18 -0400611 break;
612 mnt = mnt->mnt_parent;
613 }
614 dentry = mnt->mnt_mountpoint;
615 }
Al Viro98bc9932008-08-02 01:06:21 -0400616 return is_subdir(dentry, path->dentry);
Al Viro74c3cbe2007-07-22 08:04:18 -0400617}
618
619int audit_make_tree(struct audit_krule *rule, char *pathname, u32 op)
620{
621
622 if (pathname[0] != '/' ||
623 rule->listnr != AUDIT_FILTER_EXIT ||
Al Viro5af75d82008-12-16 05:59:26 -0500624 op != Audit_equal ||
Al Viro74c3cbe2007-07-22 08:04:18 -0400625 rule->inode_f || rule->watch || rule->tree)
626 return -EINVAL;
627 rule->tree = alloc_tree(pathname);
628 if (!rule->tree)
629 return -ENOMEM;
630 return 0;
631}
632
633void audit_put_tree(struct audit_tree *tree)
634{
635 put_tree(tree);
636}
637
638/* called with audit_filter_mutex */
639int audit_add_tree_rule(struct audit_krule *rule)
640{
641 struct audit_tree *seed = rule->tree, *tree;
Al Viro98bc9932008-08-02 01:06:21 -0400642 struct path path;
Al Viro74c3cbe2007-07-22 08:04:18 -0400643 struct vfsmount *mnt, *p;
644 struct list_head list;
645 int err;
646
647 list_for_each_entry(tree, &tree_list, list) {
648 if (!strcmp(seed->pathname, tree->pathname)) {
649 put_tree(seed);
650 rule->tree = tree;
651 list_add(&rule->rlist, &tree->rules);
652 return 0;
653 }
654 }
655 tree = seed;
656 list_add(&tree->list, &tree_list);
657 list_add(&rule->rlist, &tree->rules);
658 /* do not set rule->tree yet */
659 mutex_unlock(&audit_filter_mutex);
660
Al Viro98bc9932008-08-02 01:06:21 -0400661 err = kern_path(tree->pathname, 0, &path);
Al Viro74c3cbe2007-07-22 08:04:18 -0400662 if (err)
663 goto Err;
Al Viro589ff872009-04-18 03:28:19 -0400664 mnt = collect_mounts(&path);
Al Viro98bc9932008-08-02 01:06:21 -0400665 path_put(&path);
Al Viro74c3cbe2007-07-22 08:04:18 -0400666 if (!mnt) {
667 err = -ENOMEM;
668 goto Err;
669 }
670 list_add_tail(&list, &mnt->mnt_list);
671
672 get_tree(tree);
673 list_for_each_entry(p, &list, mnt_list) {
674 err = tag_chunk(p->mnt_root->d_inode, tree);
675 if (err)
676 break;
677 }
678
679 list_del(&list);
680 drop_collected_mounts(mnt);
681
682 if (!err) {
683 struct node *node;
684 spin_lock(&hash_lock);
685 list_for_each_entry(node, &tree->chunks, list)
686 node->index &= ~(1U<<31);
687 spin_unlock(&hash_lock);
688 } else {
689 trim_marked(tree);
690 goto Err;
691 }
692
693 mutex_lock(&audit_filter_mutex);
694 if (list_empty(&rule->rlist)) {
695 put_tree(tree);
696 return -ENOENT;
697 }
698 rule->tree = tree;
699 put_tree(tree);
700
701 return 0;
702Err:
703 mutex_lock(&audit_filter_mutex);
704 list_del_init(&tree->list);
705 list_del_init(&tree->rules);
706 put_tree(tree);
707 return err;
708}
709
710int audit_tag_tree(char *old, char *new)
711{
712 struct list_head cursor, barrier;
713 int failed = 0;
Al Viro98bc9932008-08-02 01:06:21 -0400714 struct path path;
Al Viro74c3cbe2007-07-22 08:04:18 -0400715 struct vfsmount *tagged;
716 struct list_head list;
717 struct vfsmount *mnt;
718 struct dentry *dentry;
719 int err;
720
Al Viro98bc9932008-08-02 01:06:21 -0400721 err = kern_path(new, 0, &path);
Al Viro74c3cbe2007-07-22 08:04:18 -0400722 if (err)
723 return err;
Al Viro589ff872009-04-18 03:28:19 -0400724 tagged = collect_mounts(&path);
Al Viro98bc9932008-08-02 01:06:21 -0400725 path_put(&path);
Al Viro74c3cbe2007-07-22 08:04:18 -0400726 if (!tagged)
727 return -ENOMEM;
728
Al Viro98bc9932008-08-02 01:06:21 -0400729 err = kern_path(old, 0, &path);
Al Viro74c3cbe2007-07-22 08:04:18 -0400730 if (err) {
731 drop_collected_mounts(tagged);
732 return err;
733 }
Al Viro98bc9932008-08-02 01:06:21 -0400734 mnt = mntget(path.mnt);
735 dentry = dget(path.dentry);
736 path_put(&path);
Al Viro74c3cbe2007-07-22 08:04:18 -0400737
Al Viro74c3cbe2007-07-22 08:04:18 -0400738 list_add_tail(&list, &tagged->mnt_list);
739
740 mutex_lock(&audit_filter_mutex);
741 list_add(&barrier, &tree_list);
742 list_add(&cursor, &barrier);
743
744 while (cursor.next != &tree_list) {
745 struct audit_tree *tree;
746 struct vfsmount *p;
747
748 tree = container_of(cursor.next, struct audit_tree, list);
749 get_tree(tree);
750 list_del(&cursor);
751 list_add(&cursor, &tree->list);
752 mutex_unlock(&audit_filter_mutex);
753
Al Viro98bc9932008-08-02 01:06:21 -0400754 err = kern_path(tree->pathname, 0, &path);
Al Viro74c3cbe2007-07-22 08:04:18 -0400755 if (err) {
756 put_tree(tree);
757 mutex_lock(&audit_filter_mutex);
758 continue;
759 }
760
761 spin_lock(&vfsmount_lock);
Al Viro98bc9932008-08-02 01:06:21 -0400762 if (!is_under(mnt, dentry, &path)) {
Al Viro74c3cbe2007-07-22 08:04:18 -0400763 spin_unlock(&vfsmount_lock);
Al Viro98bc9932008-08-02 01:06:21 -0400764 path_put(&path);
Al Viro74c3cbe2007-07-22 08:04:18 -0400765 put_tree(tree);
766 mutex_lock(&audit_filter_mutex);
767 continue;
768 }
769 spin_unlock(&vfsmount_lock);
Al Viro98bc9932008-08-02 01:06:21 -0400770 path_put(&path);
Al Viro74c3cbe2007-07-22 08:04:18 -0400771
772 list_for_each_entry(p, &list, mnt_list) {
773 failed = tag_chunk(p->mnt_root->d_inode, tree);
774 if (failed)
775 break;
776 }
777
778 if (failed) {
779 put_tree(tree);
780 mutex_lock(&audit_filter_mutex);
781 break;
782 }
783
784 mutex_lock(&audit_filter_mutex);
785 spin_lock(&hash_lock);
786 if (!tree->goner) {
787 list_del(&tree->list);
788 list_add(&tree->list, &tree_list);
789 }
790 spin_unlock(&hash_lock);
791 put_tree(tree);
792 }
793
794 while (barrier.prev != &tree_list) {
795 struct audit_tree *tree;
796
797 tree = container_of(barrier.prev, struct audit_tree, list);
798 get_tree(tree);
799 list_del(&tree->list);
800 list_add(&tree->list, &barrier);
801 mutex_unlock(&audit_filter_mutex);
802
803 if (!failed) {
804 struct node *node;
805 spin_lock(&hash_lock);
806 list_for_each_entry(node, &tree->chunks, list)
807 node->index &= ~(1U<<31);
808 spin_unlock(&hash_lock);
809 } else {
810 trim_marked(tree);
811 }
812
813 put_tree(tree);
814 mutex_lock(&audit_filter_mutex);
815 }
816 list_del(&barrier);
817 list_del(&cursor);
818 list_del(&list);
819 mutex_unlock(&audit_filter_mutex);
820 dput(dentry);
821 mntput(mnt);
822 drop_collected_mounts(tagged);
823 return failed;
824}
825
826/*
827 * That gets run when evict_chunk() ends up needing to kill audit_tree.
Al Viro916d7572009-06-24 00:02:38 -0400828 * Runs from a separate thread.
Al Viro74c3cbe2007-07-22 08:04:18 -0400829 */
Al Viro916d7572009-06-24 00:02:38 -0400830static int prune_tree_thread(void *unused)
Al Viro74c3cbe2007-07-22 08:04:18 -0400831{
Al Viro916d7572009-06-24 00:02:38 -0400832 mutex_lock(&audit_cmd_mutex);
Al Viro74c3cbe2007-07-22 08:04:18 -0400833 mutex_lock(&audit_filter_mutex);
834
835 while (!list_empty(&prune_list)) {
836 struct audit_tree *victim;
837
838 victim = list_entry(prune_list.next, struct audit_tree, list);
839 list_del_init(&victim->list);
840
841 mutex_unlock(&audit_filter_mutex);
842
843 prune_one(victim);
844
845 mutex_lock(&audit_filter_mutex);
846 }
847
848 mutex_unlock(&audit_filter_mutex);
Al Viro916d7572009-06-24 00:02:38 -0400849 mutex_unlock(&audit_cmd_mutex);
850 return 0;
851}
852
853static void audit_schedule_prune(void)
854{
855 kthread_run(prune_tree_thread, NULL, "audit_prune_tree");
856}
857
858/*
859 * ... and that one is done if evict_chunk() decides to delay until the end
860 * of syscall. Runs synchronously.
861 */
862void audit_kill_trees(struct list_head *list)
863{
864 mutex_lock(&audit_cmd_mutex);
865 mutex_lock(&audit_filter_mutex);
866
867 while (!list_empty(list)) {
868 struct audit_tree *victim;
869
870 victim = list_entry(list->next, struct audit_tree, list);
871 kill_rules(victim);
872 list_del_init(&victim->list);
873
874 mutex_unlock(&audit_filter_mutex);
875
876 prune_one(victim);
877
878 mutex_lock(&audit_filter_mutex);
879 }
880
881 mutex_unlock(&audit_filter_mutex);
882 mutex_unlock(&audit_cmd_mutex);
Al Viro74c3cbe2007-07-22 08:04:18 -0400883}
884
885/*
886 * Here comes the stuff asynchronous to auditctl operations
887 */
888
889/* inode->inotify_mutex is locked */
890static void evict_chunk(struct audit_chunk *chunk)
891{
892 struct audit_tree *owner;
Al Viro916d7572009-06-24 00:02:38 -0400893 struct list_head *postponed = audit_killed_trees();
894 int need_prune = 0;
Al Viro74c3cbe2007-07-22 08:04:18 -0400895 int n;
896
897 if (chunk->dead)
898 return;
899
900 chunk->dead = 1;
901 mutex_lock(&audit_filter_mutex);
902 spin_lock(&hash_lock);
903 while (!list_empty(&chunk->trees)) {
904 owner = list_entry(chunk->trees.next,
905 struct audit_tree, same_root);
906 owner->goner = 1;
907 owner->root = NULL;
908 list_del_init(&owner->same_root);
909 spin_unlock(&hash_lock);
Al Viro916d7572009-06-24 00:02:38 -0400910 if (!postponed) {
911 kill_rules(owner);
912 list_move(&owner->list, &prune_list);
913 need_prune = 1;
914 } else {
915 list_move(&owner->list, postponed);
916 }
Al Viro74c3cbe2007-07-22 08:04:18 -0400917 spin_lock(&hash_lock);
918 }
919 list_del_rcu(&chunk->hash);
920 for (n = 0; n < chunk->count; n++)
921 list_del_init(&chunk->owners[n].list);
922 spin_unlock(&hash_lock);
Al Viro916d7572009-06-24 00:02:38 -0400923 if (need_prune)
924 audit_schedule_prune();
Al Viro74c3cbe2007-07-22 08:04:18 -0400925 mutex_unlock(&audit_filter_mutex);
926}
927
928static void handle_event(struct inotify_watch *watch, u32 wd, u32 mask,
929 u32 cookie, const char *dname, struct inode *inode)
930{
931 struct audit_chunk *chunk = container_of(watch, struct audit_chunk, watch);
932
933 if (mask & IN_IGNORED) {
934 evict_chunk(chunk);
935 put_inotify_watch(watch);
936 }
937}
938
939static void destroy_watch(struct inotify_watch *watch)
940{
941 struct audit_chunk *chunk = container_of(watch, struct audit_chunk, watch);
Al Viro8f7b0ba2008-11-15 01:15:43 +0000942 call_rcu(&chunk->head, __put_chunk);
Al Viro74c3cbe2007-07-22 08:04:18 -0400943}
944
945static const struct inotify_operations rtree_inotify_ops = {
946 .handle_event = handle_event,
947 .destroy_watch = destroy_watch,
948};
949
950static int __init audit_tree_init(void)
951{
952 int i;
953
954 rtree_ih = inotify_init(&rtree_inotify_ops);
955 if (IS_ERR(rtree_ih))
956 audit_panic("cannot initialize inotify handle for rectree watches");
957
958 for (i = 0; i < HASH_SIZE; i++)
959 INIT_LIST_HEAD(&chunk_hash_heads[i]);
960
961 return 0;
962}
963__initcall(audit_tree_init);