Audit: clean up all op= output to include string quoting
[linux-2.6.git] / kernel / audit_tree.c
1 #include "audit.h"
2 #include <linux/inotify.h>
3 #include <linux/namei.h>
4 #include <linux/mount.h>
5
6 struct audit_tree;
7 struct audit_chunk;
8
9 struct audit_tree {
10         atomic_t count;
11         int goner;
12         struct audit_chunk *root;
13         struct list_head chunks;
14         struct list_head rules;
15         struct list_head list;
16         struct list_head same_root;
17         struct rcu_head head;
18         char pathname[];
19 };
20
21 struct audit_chunk {
22         struct list_head hash;
23         struct inotify_watch watch;
24         struct list_head trees;         /* with root here */
25         int dead;
26         int count;
27         atomic_long_t refs;
28         struct rcu_head head;
29         struct node {
30                 struct list_head list;
31                 struct audit_tree *owner;
32                 unsigned index;         /* index; upper bit indicates 'will prune' */
33         } owners[];
34 };
35
36 static LIST_HEAD(tree_list);
37 static LIST_HEAD(prune_list);
38
39 /*
40  * One struct chunk is attached to each inode of interest.
41  * We replace struct chunk on tagging/untagging.
42  * Rules have pointer to struct audit_tree.
43  * Rules have struct list_head rlist forming a list of rules over
44  * the same tree.
45  * References to struct chunk are collected at audit_inode{,_child}()
46  * time and used in AUDIT_TREE rule matching.
47  * These references are dropped at the same time we are calling
48  * audit_free_names(), etc.
49  *
50  * Cyclic lists galore:
51  * tree.chunks anchors chunk.owners[].list                      hash_lock
52  * tree.rules anchors rule.rlist                                audit_filter_mutex
53  * chunk.trees anchors tree.same_root                           hash_lock
54  * chunk.hash is a hash with middle bits of watch.inode as
55  * a hash function.                                             RCU, hash_lock
56  *
57  * tree is refcounted; one reference for "some rules on rules_list refer to
58  * it", one for each chunk with pointer to it.
59  *
60  * chunk is refcounted by embedded inotify_watch + .refs (non-zero refcount
61  * of watch contributes 1 to .refs).
62  *
63  * node.index allows to get from node.list to containing chunk.
64  * MSB of that sucker is stolen to mark taggings that we might have to
65  * revert - several operations have very unpleasant cleanup logics and
66  * that makes a difference.  Some.
67  */
68
69 static struct inotify_handle *rtree_ih;
70
71 static struct audit_tree *alloc_tree(const char *s)
72 {
73         struct audit_tree *tree;
74
75         tree = kmalloc(sizeof(struct audit_tree) + strlen(s) + 1, GFP_KERNEL);
76         if (tree) {
77                 atomic_set(&tree->count, 1);
78                 tree->goner = 0;
79                 INIT_LIST_HEAD(&tree->chunks);
80                 INIT_LIST_HEAD(&tree->rules);
81                 INIT_LIST_HEAD(&tree->list);
82                 INIT_LIST_HEAD(&tree->same_root);
83                 tree->root = NULL;
84                 strcpy(tree->pathname, s);
85         }
86         return tree;
87 }
88
89 static inline void get_tree(struct audit_tree *tree)
90 {
91         atomic_inc(&tree->count);
92 }
93
94 static void __put_tree(struct rcu_head *rcu)
95 {
96         struct audit_tree *tree = container_of(rcu, struct audit_tree, head);
97         kfree(tree);
98 }
99
100 static inline void put_tree(struct audit_tree *tree)
101 {
102         if (atomic_dec_and_test(&tree->count))
103                 call_rcu(&tree->head, __put_tree);
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
112 static struct audit_chunk *alloc_chunk(int count)
113 {
114         struct audit_chunk *chunk;
115         size_t size;
116         int i;
117
118         size = offsetof(struct audit_chunk, owners) + count * sizeof(struct node);
119         chunk = kzalloc(size, GFP_KERNEL);
120         if (!chunk)
121                 return NULL;
122
123         INIT_LIST_HEAD(&chunk->hash);
124         INIT_LIST_HEAD(&chunk->trees);
125         chunk->count = count;
126         atomic_long_set(&chunk->refs, 1);
127         for (i = 0; i < count; i++) {
128                 INIT_LIST_HEAD(&chunk->owners[i].list);
129                 chunk->owners[i].index = i;
130         }
131         inotify_init_watch(&chunk->watch);
132         return chunk;
133 }
134
135 static void free_chunk(struct audit_chunk *chunk)
136 {
137         int i;
138
139         for (i = 0; i < chunk->count; i++) {
140                 if (chunk->owners[i].owner)
141                         put_tree(chunk->owners[i].owner);
142         }
143         kfree(chunk);
144 }
145
146 void audit_put_chunk(struct audit_chunk *chunk)
147 {
148         if (atomic_long_dec_and_test(&chunk->refs))
149                 free_chunk(chunk);
150 }
151
152 static void __put_chunk(struct rcu_head *rcu)
153 {
154         struct audit_chunk *chunk = container_of(rcu, struct audit_chunk, head);
155         audit_put_chunk(chunk);
156 }
157
158 enum {HASH_SIZE = 128};
159 static struct list_head chunk_hash_heads[HASH_SIZE];
160 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(hash_lock);
161
162 static inline struct list_head *chunk_hash(const struct inode *inode)
163 {
164         unsigned long n = (unsigned long)inode / L1_CACHE_BYTES;
165         return chunk_hash_heads + n % HASH_SIZE;
166 }
167
168 /* hash_lock is held by caller */
169 static void insert_hash(struct audit_chunk *chunk)
170 {
171         struct list_head *list = chunk_hash(chunk->watch.inode);
172         list_add_rcu(&chunk->hash, list);
173 }
174
175 /* called under rcu_read_lock */
176 struct audit_chunk *audit_tree_lookup(const struct inode *inode)
177 {
178         struct list_head *list = chunk_hash(inode);
179         struct audit_chunk *p;
180
181         list_for_each_entry_rcu(p, list, hash) {
182                 if (p->watch.inode == inode) {
183                         atomic_long_inc(&p->refs);
184                         return p;
185                 }
186         }
187         return NULL;
188 }
189
190 int audit_tree_match(struct audit_chunk *chunk, struct audit_tree *tree)
191 {
192         int n;
193         for (n = 0; n < chunk->count; n++)
194                 if (chunk->owners[n].owner == tree)
195                         return 1;
196         return 0;
197 }
198
199 /* tagging and untagging inodes with trees */
200
201 static struct audit_chunk *find_chunk(struct node *p)
202 {
203         int index = p->index & ~(1U<<31);
204         p -= index;
205         return container_of(p, struct audit_chunk, owners[0]);
206 }
207
208 static void untag_chunk(struct node *p)
209 {
210         struct audit_chunk *chunk = find_chunk(p);
211         struct audit_chunk *new;
212         struct audit_tree *owner;
213         int size = chunk->count - 1;
214         int i, j;
215
216         if (!pin_inotify_watch(&chunk->watch)) {
217                 /*
218                  * Filesystem is shutting down; all watches are getting
219                  * evicted, just take it off the node list for this
220                  * tree and let the eviction logics take care of the
221                  * rest.
222                  */
223                 owner = p->owner;
224                 if (owner->root == chunk) {
225                         list_del_init(&owner->same_root);
226                         owner->root = NULL;
227                 }
228                 list_del_init(&p->list);
229                 p->owner = NULL;
230                 put_tree(owner);
231                 return;
232         }
233
234         spin_unlock(&hash_lock);
235
236         /*
237          * pin_inotify_watch() succeeded, so the watch won't go away
238          * from under us.
239          */
240         mutex_lock(&chunk->watch.inode->inotify_mutex);
241         if (chunk->dead) {
242                 mutex_unlock(&chunk->watch.inode->inotify_mutex);
243                 goto out;
244         }
245
246         owner = p->owner;
247
248         if (!size) {
249                 chunk->dead = 1;
250                 spin_lock(&hash_lock);
251                 list_del_init(&chunk->trees);
252                 if (owner->root == chunk)
253                         owner->root = NULL;
254                 list_del_init(&p->list);
255                 list_del_rcu(&chunk->hash);
256                 spin_unlock(&hash_lock);
257                 inotify_evict_watch(&chunk->watch);
258                 mutex_unlock(&chunk->watch.inode->inotify_mutex);
259                 put_inotify_watch(&chunk->watch);
260                 goto out;
261         }
262
263         new = alloc_chunk(size);
264         if (!new)
265                 goto Fallback;
266         if (inotify_clone_watch(&chunk->watch, &new->watch) < 0) {
267                 free_chunk(new);
268                 goto Fallback;
269         }
270
271         chunk->dead = 1;
272         spin_lock(&hash_lock);
273         list_replace_init(&chunk->trees, &new->trees);
274         if (owner->root == chunk) {
275                 list_del_init(&owner->same_root);
276                 owner->root = NULL;
277         }
278
279         for (i = j = 0; i < size; i++, j++) {
280                 struct audit_tree *s;
281                 if (&chunk->owners[j] == p) {
282                         list_del_init(&p->list);
283                         i--;
284                         continue;
285                 }
286                 s = chunk->owners[j].owner;
287                 new->owners[i].owner = s;
288                 new->owners[i].index = chunk->owners[j].index - j + i;
289                 if (!s) /* result of earlier fallback */
290                         continue;
291                 get_tree(s);
292                 list_replace_init(&chunk->owners[i].list, &new->owners[j].list);
293         }
294
295         list_replace_rcu(&chunk->hash, &new->hash);
296         list_for_each_entry(owner, &new->trees, same_root)
297                 owner->root = new;
298         spin_unlock(&hash_lock);
299         inotify_evict_watch(&chunk->watch);
300         mutex_unlock(&chunk->watch.inode->inotify_mutex);
301         put_inotify_watch(&chunk->watch);
302         goto out;
303
304 Fallback:
305         // do the best we can
306         spin_lock(&hash_lock);
307         if (owner->root == chunk) {
308                 list_del_init(&owner->same_root);
309                 owner->root = NULL;
310         }
311         list_del_init(&p->list);
312         p->owner = NULL;
313         put_tree(owner);
314         spin_unlock(&hash_lock);
315         mutex_unlock(&chunk->watch.inode->inotify_mutex);
316 out:
317         unpin_inotify_watch(&chunk->watch);
318         spin_lock(&hash_lock);
319 }
320
321 static int create_chunk(struct inode *inode, struct audit_tree *tree)
322 {
323         struct audit_chunk *chunk = alloc_chunk(1);
324         if (!chunk)
325                 return -ENOMEM;
326
327         if (inotify_add_watch(rtree_ih, &chunk->watch, inode, IN_IGNORED | IN_DELETE_SELF) < 0) {
328                 free_chunk(chunk);
329                 return -ENOSPC;
330         }
331
332         mutex_lock(&inode->inotify_mutex);
333         spin_lock(&hash_lock);
334         if (tree->goner) {
335                 spin_unlock(&hash_lock);
336                 chunk->dead = 1;
337                 inotify_evict_watch(&chunk->watch);
338                 mutex_unlock(&inode->inotify_mutex);
339                 put_inotify_watch(&chunk->watch);
340                 return 0;
341         }
342         chunk->owners[0].index = (1U << 31);
343         chunk->owners[0].owner = tree;
344         get_tree(tree);
345         list_add(&chunk->owners[0].list, &tree->chunks);
346         if (!tree->root) {
347                 tree->root = chunk;
348                 list_add(&tree->same_root, &chunk->trees);
349         }
350         insert_hash(chunk);
351         spin_unlock(&hash_lock);
352         mutex_unlock(&inode->inotify_mutex);
353         return 0;
354 }
355
356 /* the first tagged inode becomes root of tree */
357 static int tag_chunk(struct inode *inode, struct audit_tree *tree)
358 {
359         struct inotify_watch *watch;
360         struct audit_tree *owner;
361         struct audit_chunk *chunk, *old;
362         struct node *p;
363         int n;
364
365         if (inotify_find_watch(rtree_ih, inode, &watch) < 0)
366                 return create_chunk(inode, tree);
367
368         old = container_of(watch, struct audit_chunk, watch);
369
370         /* are we already there? */
371         spin_lock(&hash_lock);
372         for (n = 0; n < old->count; n++) {
373                 if (old->owners[n].owner == tree) {
374                         spin_unlock(&hash_lock);
375                         put_inotify_watch(watch);
376                         return 0;
377                 }
378         }
379         spin_unlock(&hash_lock);
380
381         chunk = alloc_chunk(old->count + 1);
382         if (!chunk)
383                 return -ENOMEM;
384
385         mutex_lock(&inode->inotify_mutex);
386         if (inotify_clone_watch(&old->watch, &chunk->watch) < 0) {
387                 mutex_unlock(&inode->inotify_mutex);
388                 put_inotify_watch(&old->watch);
389                 free_chunk(chunk);
390                 return -ENOSPC;
391         }
392         spin_lock(&hash_lock);
393         if (tree->goner) {
394                 spin_unlock(&hash_lock);
395                 chunk->dead = 1;
396                 inotify_evict_watch(&chunk->watch);
397                 mutex_unlock(&inode->inotify_mutex);
398                 put_inotify_watch(&old->watch);
399                 put_inotify_watch(&chunk->watch);
400                 return 0;
401         }
402         list_replace_init(&old->trees, &chunk->trees);
403         for (n = 0, p = chunk->owners; n < old->count; n++, p++) {
404                 struct audit_tree *s = old->owners[n].owner;
405                 p->owner = s;
406                 p->index = old->owners[n].index;
407                 if (!s) /* result of fallback in untag */
408                         continue;
409                 get_tree(s);
410                 list_replace_init(&old->owners[n].list, &p->list);
411         }
412         p->index = (chunk->count - 1) | (1U<<31);
413         p->owner = tree;
414         get_tree(tree);
415         list_add(&p->list, &tree->chunks);
416         list_replace_rcu(&old->hash, &chunk->hash);
417         list_for_each_entry(owner, &chunk->trees, same_root)
418                 owner->root = chunk;
419         old->dead = 1;
420         if (!tree->root) {
421                 tree->root = chunk;
422                 list_add(&tree->same_root, &chunk->trees);
423         }
424         spin_unlock(&hash_lock);
425         inotify_evict_watch(&old->watch);
426         mutex_unlock(&inode->inotify_mutex);
427         put_inotify_watch(&old->watch);
428         return 0;
429 }
430
431 static void kill_rules(struct audit_tree *tree)
432 {
433         struct audit_krule *rule, *next;
434         struct audit_entry *entry;
435         struct audit_buffer *ab;
436
437         list_for_each_entry_safe(rule, next, &tree->rules, rlist) {
438                 entry = container_of(rule, struct audit_entry, rule);
439
440                 list_del_init(&rule->rlist);
441                 if (rule->tree) {
442                         /* not a half-baked one */
443                         ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
444                         audit_log_format(ab, "op=");
445                         audit_log_string(ab, "remove rule");
446                         audit_log_format(ab, " dir=");
447                         audit_log_untrustedstring(ab, rule->tree->pathname);
448                         audit_log_key(ab, rule->filterkey);
449                         audit_log_format(ab, " list=%d res=1", rule->listnr);
450                         audit_log_end(ab);
451                         rule->tree = NULL;
452                         list_del_rcu(&entry->list);
453                         list_del(&entry->rule.list);
454                         call_rcu(&entry->rcu, audit_free_rule_rcu);
455                 }
456         }
457 }
458
459 /*
460  * finish killing struct audit_tree
461  */
462 static void prune_one(struct audit_tree *victim)
463 {
464         spin_lock(&hash_lock);
465         while (!list_empty(&victim->chunks)) {
466                 struct node *p;
467
468                 p = list_entry(victim->chunks.next, struct node, list);
469
470                 untag_chunk(p);
471         }
472         spin_unlock(&hash_lock);
473         put_tree(victim);
474 }
475
476 /* trim the uncommitted chunks from tree */
477
478 static void trim_marked(struct audit_tree *tree)
479 {
480         struct list_head *p, *q;
481         spin_lock(&hash_lock);
482         if (tree->goner) {
483                 spin_unlock(&hash_lock);
484                 return;
485         }
486         /* reorder */
487         for (p = tree->chunks.next; p != &tree->chunks; p = q) {
488                 struct node *node = list_entry(p, struct node, list);
489                 q = p->next;
490                 if (node->index & (1U<<31)) {
491                         list_del_init(p);
492                         list_add(p, &tree->chunks);
493                 }
494         }
495
496         while (!list_empty(&tree->chunks)) {
497                 struct node *node;
498
499                 node = list_entry(tree->chunks.next, struct node, list);
500
501                 /* have we run out of marked? */
502                 if (!(node->index & (1U<<31)))
503                         break;
504
505                 untag_chunk(node);
506         }
507         if (!tree->root && !tree->goner) {
508                 tree->goner = 1;
509                 spin_unlock(&hash_lock);
510                 mutex_lock(&audit_filter_mutex);
511                 kill_rules(tree);
512                 list_del_init(&tree->list);
513                 mutex_unlock(&audit_filter_mutex);
514                 prune_one(tree);
515         } else {
516                 spin_unlock(&hash_lock);
517         }
518 }
519
520 /* called with audit_filter_mutex */
521 int audit_remove_tree_rule(struct audit_krule *rule)
522 {
523         struct audit_tree *tree;
524         tree = rule->tree;
525         if (tree) {
526                 spin_lock(&hash_lock);
527                 list_del_init(&rule->rlist);
528                 if (list_empty(&tree->rules) && !tree->goner) {
529                         tree->root = NULL;
530                         list_del_init(&tree->same_root);
531                         tree->goner = 1;
532                         list_move(&tree->list, &prune_list);
533                         rule->tree = NULL;
534                         spin_unlock(&hash_lock);
535                         audit_schedule_prune();
536                         return 1;
537                 }
538                 rule->tree = NULL;
539                 spin_unlock(&hash_lock);
540                 return 1;
541         }
542         return 0;
543 }
544
545 void audit_trim_trees(void)
546 {
547         struct list_head cursor;
548
549         mutex_lock(&audit_filter_mutex);
550         list_add(&cursor, &tree_list);
551         while (cursor.next != &tree_list) {
552                 struct audit_tree *tree;
553                 struct path path;
554                 struct vfsmount *root_mnt;
555                 struct node *node;
556                 struct list_head list;
557                 int err;
558
559                 tree = container_of(cursor.next, struct audit_tree, list);
560                 get_tree(tree);
561                 list_del(&cursor);
562                 list_add(&cursor, &tree->list);
563                 mutex_unlock(&audit_filter_mutex);
564
565                 err = kern_path(tree->pathname, 0, &path);
566                 if (err)
567                         goto skip_it;
568
569                 root_mnt = collect_mounts(&path);
570                 path_put(&path);
571                 if (!root_mnt)
572                         goto skip_it;
573
574                 list_add_tail(&list, &root_mnt->mnt_list);
575                 spin_lock(&hash_lock);
576                 list_for_each_entry(node, &tree->chunks, list) {
577                         struct audit_chunk *chunk = find_chunk(node);
578                         struct inode *inode = chunk->watch.inode;
579                         struct vfsmount *mnt;
580                         node->index |= 1U<<31;
581                         list_for_each_entry(mnt, &list, mnt_list) {
582                                 if (mnt->mnt_root->d_inode == inode) {
583                                         node->index &= ~(1U<<31);
584                                         break;
585                                 }
586                         }
587                 }
588                 spin_unlock(&hash_lock);
589                 trim_marked(tree);
590                 put_tree(tree);
591                 list_del_init(&list);
592                 drop_collected_mounts(root_mnt);
593 skip_it:
594                 mutex_lock(&audit_filter_mutex);
595         }
596         list_del(&cursor);
597         mutex_unlock(&audit_filter_mutex);
598 }
599
600 static int is_under(struct vfsmount *mnt, struct dentry *dentry,
601                     struct path *path)
602 {
603         if (mnt != path->mnt) {
604                 for (;;) {
605                         if (mnt->mnt_parent == mnt)
606                                 return 0;
607                         if (mnt->mnt_parent == path->mnt)
608                                         break;
609                         mnt = mnt->mnt_parent;
610                 }
611                 dentry = mnt->mnt_mountpoint;
612         }
613         return is_subdir(dentry, path->dentry);
614 }
615
616 int audit_make_tree(struct audit_krule *rule, char *pathname, u32 op)
617 {
618
619         if (pathname[0] != '/' ||
620             rule->listnr != AUDIT_FILTER_EXIT ||
621             op != Audit_equal ||
622             rule->inode_f || rule->watch || rule->tree)
623                 return -EINVAL;
624         rule->tree = alloc_tree(pathname);
625         if (!rule->tree)
626                 return -ENOMEM;
627         return 0;
628 }
629
630 void audit_put_tree(struct audit_tree *tree)
631 {
632         put_tree(tree);
633 }
634
635 /* called with audit_filter_mutex */
636 int audit_add_tree_rule(struct audit_krule *rule)
637 {
638         struct audit_tree *seed = rule->tree, *tree;
639         struct path path;
640         struct vfsmount *mnt, *p;
641         struct list_head list;
642         int err;
643
644         list_for_each_entry(tree, &tree_list, list) {
645                 if (!strcmp(seed->pathname, tree->pathname)) {
646                         put_tree(seed);
647                         rule->tree = tree;
648                         list_add(&rule->rlist, &tree->rules);
649                         return 0;
650                 }
651         }
652         tree = seed;
653         list_add(&tree->list, &tree_list);
654         list_add(&rule->rlist, &tree->rules);
655         /* do not set rule->tree yet */
656         mutex_unlock(&audit_filter_mutex);
657
658         err = kern_path(tree->pathname, 0, &path);
659         if (err)
660                 goto Err;
661         mnt = collect_mounts(&path);
662         path_put(&path);
663         if (!mnt) {
664                 err = -ENOMEM;
665                 goto Err;
666         }
667         list_add_tail(&list, &mnt->mnt_list);
668
669         get_tree(tree);
670         list_for_each_entry(p, &list, mnt_list) {
671                 err = tag_chunk(p->mnt_root->d_inode, tree);
672                 if (err)
673                         break;
674         }
675
676         list_del(&list);
677         drop_collected_mounts(mnt);
678
679         if (!err) {
680                 struct node *node;
681                 spin_lock(&hash_lock);
682                 list_for_each_entry(node, &tree->chunks, list)
683                         node->index &= ~(1U<<31);
684                 spin_unlock(&hash_lock);
685         } else {
686                 trim_marked(tree);
687                 goto Err;
688         }
689
690         mutex_lock(&audit_filter_mutex);
691         if (list_empty(&rule->rlist)) {
692                 put_tree(tree);
693                 return -ENOENT;
694         }
695         rule->tree = tree;
696         put_tree(tree);
697
698         return 0;
699 Err:
700         mutex_lock(&audit_filter_mutex);
701         list_del_init(&tree->list);
702         list_del_init(&tree->rules);
703         put_tree(tree);
704         return err;
705 }
706
707 int audit_tag_tree(char *old, char *new)
708 {
709         struct list_head cursor, barrier;
710         int failed = 0;
711         struct path path;
712         struct vfsmount *tagged;
713         struct list_head list;
714         struct vfsmount *mnt;
715         struct dentry *dentry;
716         int err;
717
718         err = kern_path(new, 0, &path);
719         if (err)
720                 return err;
721         tagged = collect_mounts(&path);
722         path_put(&path);
723         if (!tagged)
724                 return -ENOMEM;
725
726         err = kern_path(old, 0, &path);
727         if (err) {
728                 drop_collected_mounts(tagged);
729                 return err;
730         }
731         mnt = mntget(path.mnt);
732         dentry = dget(path.dentry);
733         path_put(&path);
734
735         list_add_tail(&list, &tagged->mnt_list);
736
737         mutex_lock(&audit_filter_mutex);
738         list_add(&barrier, &tree_list);
739         list_add(&cursor, &barrier);
740
741         while (cursor.next != &tree_list) {
742                 struct audit_tree *tree;
743                 struct vfsmount *p;
744
745                 tree = container_of(cursor.next, struct audit_tree, list);
746                 get_tree(tree);
747                 list_del(&cursor);
748                 list_add(&cursor, &tree->list);
749                 mutex_unlock(&audit_filter_mutex);
750
751                 err = kern_path(tree->pathname, 0, &path);
752                 if (err) {
753                         put_tree(tree);
754                         mutex_lock(&audit_filter_mutex);
755                         continue;
756                 }
757
758                 spin_lock(&vfsmount_lock);
759                 if (!is_under(mnt, dentry, &path)) {
760                         spin_unlock(&vfsmount_lock);
761                         path_put(&path);
762                         put_tree(tree);
763                         mutex_lock(&audit_filter_mutex);
764                         continue;
765                 }
766                 spin_unlock(&vfsmount_lock);
767                 path_put(&path);
768
769                 list_for_each_entry(p, &list, mnt_list) {
770                         failed = tag_chunk(p->mnt_root->d_inode, tree);
771                         if (failed)
772                                 break;
773                 }
774
775                 if (failed) {
776                         put_tree(tree);
777                         mutex_lock(&audit_filter_mutex);
778                         break;
779                 }
780
781                 mutex_lock(&audit_filter_mutex);
782                 spin_lock(&hash_lock);
783                 if (!tree->goner) {
784                         list_del(&tree->list);
785                         list_add(&tree->list, &tree_list);
786                 }
787                 spin_unlock(&hash_lock);
788                 put_tree(tree);
789         }
790
791         while (barrier.prev != &tree_list) {
792                 struct audit_tree *tree;
793
794                 tree = container_of(barrier.prev, struct audit_tree, list);
795                 get_tree(tree);
796                 list_del(&tree->list);
797                 list_add(&tree->list, &barrier);
798                 mutex_unlock(&audit_filter_mutex);
799
800                 if (!failed) {
801                         struct node *node;
802                         spin_lock(&hash_lock);
803                         list_for_each_entry(node, &tree->chunks, list)
804                                 node->index &= ~(1U<<31);
805                         spin_unlock(&hash_lock);
806                 } else {
807                         trim_marked(tree);
808                 }
809
810                 put_tree(tree);
811                 mutex_lock(&audit_filter_mutex);
812         }
813         list_del(&barrier);
814         list_del(&cursor);
815         list_del(&list);
816         mutex_unlock(&audit_filter_mutex);
817         dput(dentry);
818         mntput(mnt);
819         drop_collected_mounts(tagged);
820         return failed;
821 }
822
823 /*
824  * That gets run when evict_chunk() ends up needing to kill audit_tree.
825  * Runs from a separate thread, with audit_cmd_mutex held.
826  */
827 void audit_prune_trees(void)
828 {
829         mutex_lock(&audit_filter_mutex);
830
831         while (!list_empty(&prune_list)) {
832                 struct audit_tree *victim;
833
834                 victim = list_entry(prune_list.next, struct audit_tree, list);
835                 list_del_init(&victim->list);
836
837                 mutex_unlock(&audit_filter_mutex);
838
839                 prune_one(victim);
840
841                 mutex_lock(&audit_filter_mutex);
842         }
843
844         mutex_unlock(&audit_filter_mutex);
845 }
846
847 /*
848  *  Here comes the stuff asynchronous to auditctl operations
849  */
850
851 /* inode->inotify_mutex is locked */
852 static void evict_chunk(struct audit_chunk *chunk)
853 {
854         struct audit_tree *owner;
855         int n;
856
857         if (chunk->dead)
858                 return;
859
860         chunk->dead = 1;
861         mutex_lock(&audit_filter_mutex);
862         spin_lock(&hash_lock);
863         while (!list_empty(&chunk->trees)) {
864                 owner = list_entry(chunk->trees.next,
865                                    struct audit_tree, same_root);
866                 owner->goner = 1;
867                 owner->root = NULL;
868                 list_del_init(&owner->same_root);
869                 spin_unlock(&hash_lock);
870                 kill_rules(owner);
871                 list_move(&owner->list, &prune_list);
872                 audit_schedule_prune();
873                 spin_lock(&hash_lock);
874         }
875         list_del_rcu(&chunk->hash);
876         for (n = 0; n < chunk->count; n++)
877                 list_del_init(&chunk->owners[n].list);
878         spin_unlock(&hash_lock);
879         mutex_unlock(&audit_filter_mutex);
880 }
881
882 static void handle_event(struct inotify_watch *watch, u32 wd, u32 mask,
883                          u32 cookie, const char *dname, struct inode *inode)
884 {
885         struct audit_chunk *chunk = container_of(watch, struct audit_chunk, watch);
886
887         if (mask & IN_IGNORED) {
888                 evict_chunk(chunk);
889                 put_inotify_watch(watch);
890         }
891 }
892
893 static void destroy_watch(struct inotify_watch *watch)
894 {
895         struct audit_chunk *chunk = container_of(watch, struct audit_chunk, watch);
896         call_rcu(&chunk->head, __put_chunk);
897 }
898
899 static const struct inotify_operations rtree_inotify_ops = {
900         .handle_event   = handle_event,
901         .destroy_watch  = destroy_watch,
902 };
903
904 static int __init audit_tree_init(void)
905 {
906         int i;
907
908         rtree_ih = inotify_init(&rtree_inotify_ops);
909         if (IS_ERR(rtree_ih))
910                 audit_panic("cannot initialize inotify handle for rectree watches");
911
912         for (i = 0; i < HASH_SIZE; i++)
913                 INIT_LIST_HEAD(&chunk_hash_heads[i]);
914
915         return 0;
916 }
917 __initcall(audit_tree_init);