1 /* audit_watch.c -- watching inodes
3 * Copyright 2003-2009 Red Hat, Inc.
4 * Copyright 2005 Hewlett-Packard Development Company, L.P.
5 * Copyright 2005 IBM Corporation
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 #include <linux/kernel.h>
23 #include <linux/audit.h>
24 #include <linux/kthread.h>
25 #include <linux/mutex.h>
27 #include <linux/fsnotify_backend.h>
28 #include <linux/namei.h>
29 #include <linux/netlink.h>
30 #include <linux/sched.h>
31 #include <linux/slab.h>
32 #include <linux/security.h>
38 * audit_parent: lifetime is from audit_init_parent() to receipt of an FS_IGNORED
39 * event. Each audit_watch holds a reference to its associated parent.
41 * audit_watch: if added to lists, lifetime is from audit_init_watch() to
42 * audit_remove_watch(). Additionally, an audit_watch may exist
43 * temporarily to assist in searching existing filter data. Each
44 * audit_krule holds a reference to its associated watch.
48 atomic_t count; /* reference count */
49 dev_t dev; /* associated superblock device */
50 char *path; /* insertion path */
51 unsigned long ino; /* associated inode number */
52 struct audit_parent *parent; /* associated parent */
53 struct list_head wlist; /* entry in parent->watches list */
54 struct list_head rules; /* anchor for krule->rlist */
58 struct list_head watches; /* anchor for audit_watch->wlist */
59 struct fsnotify_mark mark; /* fsnotify mark on the inode */
62 /* fsnotify handle. */
63 static struct fsnotify_group *audit_watch_group;
65 /* fsnotify events we care about. */
66 #define AUDIT_FS_WATCH (FS_MOVE | FS_CREATE | FS_DELETE | FS_DELETE_SELF |\
67 FS_MOVE_SELF | FS_EVENT_ON_CHILD)
69 static void audit_free_parent(struct audit_parent *parent)
71 WARN_ON(!list_empty(&parent->watches));
75 static void audit_watch_free_mark(struct fsnotify_mark *entry)
77 struct audit_parent *parent;
79 parent = container_of(entry, struct audit_parent, mark);
80 audit_free_parent(parent);
83 static void audit_get_parent(struct audit_parent *parent)
86 fsnotify_get_mark(&parent->mark);
89 static void audit_put_parent(struct audit_parent *parent)
92 fsnotify_put_mark(&parent->mark);
96 * Find and return the audit_parent on the given inode. If found a reference
97 * is taken on this parent.
99 static inline struct audit_parent *audit_find_parent(struct inode *inode)
101 struct audit_parent *parent = NULL;
102 struct fsnotify_mark *entry;
104 entry = fsnotify_find_inode_mark(audit_watch_group, inode);
106 parent = container_of(entry, struct audit_parent, mark);
111 void audit_get_watch(struct audit_watch *watch)
113 atomic_inc(&watch->count);
116 void audit_put_watch(struct audit_watch *watch)
118 if (atomic_dec_and_test(&watch->count)) {
119 WARN_ON(watch->parent);
120 WARN_ON(!list_empty(&watch->rules));
126 static void audit_remove_watch(struct audit_watch *watch)
128 list_del(&watch->wlist);
129 audit_put_parent(watch->parent);
130 watch->parent = NULL;
131 audit_put_watch(watch); /* match initial get */
134 char *audit_watch_path(struct audit_watch *watch)
139 int audit_watch_compare(struct audit_watch *watch, unsigned long ino, dev_t dev)
141 return (watch->ino != (unsigned long)-1) &&
142 (watch->ino == ino) &&
146 /* Initialize a parent watch entry. */
147 static struct audit_parent *audit_init_parent(struct path *path)
149 struct inode *inode = path->dentry->d_inode;
150 struct audit_parent *parent;
153 parent = kzalloc(sizeof(*parent), GFP_KERNEL);
154 if (unlikely(!parent))
155 return ERR_PTR(-ENOMEM);
157 INIT_LIST_HEAD(&parent->watches);
159 fsnotify_init_mark(&parent->mark, audit_watch_free_mark);
160 parent->mark.mask = AUDIT_FS_WATCH;
161 ret = fsnotify_add_mark(&parent->mark, audit_watch_group, inode, NULL, 0);
163 audit_free_parent(parent);
170 /* Initialize a watch entry. */
171 static struct audit_watch *audit_init_watch(char *path)
173 struct audit_watch *watch;
175 watch = kzalloc(sizeof(*watch), GFP_KERNEL);
176 if (unlikely(!watch))
177 return ERR_PTR(-ENOMEM);
179 INIT_LIST_HEAD(&watch->rules);
180 atomic_set(&watch->count, 1);
182 watch->dev = (dev_t)-1;
183 watch->ino = (unsigned long)-1;
188 /* Translate a watch string to kernel respresentation. */
189 int audit_to_watch(struct audit_krule *krule, char *path, int len, u32 op)
191 struct audit_watch *watch;
193 if (!audit_watch_group)
196 if (path[0] != '/' || path[len-1] == '/' ||
197 krule->listnr != AUDIT_FILTER_EXIT ||
199 krule->inode_f || krule->watch || krule->tree)
202 watch = audit_init_watch(path);
204 return PTR_ERR(watch);
206 audit_get_watch(watch);
207 krule->watch = watch;
212 /* Duplicate the given audit watch. The new watch's rules list is initialized
213 * to an empty list and wlist is undefined. */
214 static struct audit_watch *audit_dupe_watch(struct audit_watch *old)
217 struct audit_watch *new;
219 path = kstrdup(old->path, GFP_KERNEL);
221 return ERR_PTR(-ENOMEM);
223 new = audit_init_watch(path);
231 audit_get_parent(old->parent);
232 new->parent = old->parent;
238 static void audit_watch_log_rule_change(struct audit_krule *r, struct audit_watch *w, char *op)
241 struct audit_buffer *ab;
242 ab = audit_log_start(NULL, GFP_NOFS, AUDIT_CONFIG_CHANGE);
245 audit_log_format(ab, "auid=%u ses=%u op=",
246 from_kuid(&init_user_ns, audit_get_loginuid(current)),
247 audit_get_sessionid(current));
248 audit_log_string(ab, op);
249 audit_log_format(ab, " path=");
250 audit_log_untrustedstring(ab, w->path);
251 audit_log_key(ab, r->filterkey);
252 audit_log_format(ab, " list=%d res=1", r->listnr);
257 /* Update inode info in audit rules based on filesystem event. */
258 static void audit_update_watch(struct audit_parent *parent,
259 const char *dname, dev_t dev,
260 unsigned long ino, unsigned invalidating)
262 struct audit_watch *owatch, *nwatch, *nextw;
263 struct audit_krule *r, *nextr;
264 struct audit_entry *oentry, *nentry;
266 mutex_lock(&audit_filter_mutex);
267 /* Run all of the watches on this parent looking for the one that
268 * matches the given dname */
269 list_for_each_entry_safe(owatch, nextw, &parent->watches, wlist) {
270 if (audit_compare_dname_path(dname, owatch->path,
274 /* If the update involves invalidating rules, do the inode-based
275 * filtering now, so we don't omit records. */
276 if (invalidating && !audit_dummy_context())
277 audit_filter_inodes(current, current->audit_context);
279 /* updating ino will likely change which audit_hash_list we
280 * are on so we need a new watch for the new list */
281 nwatch = audit_dupe_watch(owatch);
282 if (IS_ERR(nwatch)) {
283 mutex_unlock(&audit_filter_mutex);
284 audit_panic("error updating watch, skipping");
290 list_for_each_entry_safe(r, nextr, &owatch->rules, rlist) {
292 oentry = container_of(r, struct audit_entry, rule);
293 list_del(&oentry->rule.rlist);
294 list_del_rcu(&oentry->list);
296 nentry = audit_dupe_rule(&oentry->rule);
297 if (IS_ERR(nentry)) {
298 list_del(&oentry->rule.list);
299 audit_panic("error updating watch, removing");
301 int h = audit_hash_ino((u32)ino);
304 * nentry->rule.watch == oentry->rule.watch so
305 * we must drop that reference and set it to our
308 audit_put_watch(nentry->rule.watch);
309 audit_get_watch(nwatch);
310 nentry->rule.watch = nwatch;
311 list_add(&nentry->rule.rlist, &nwatch->rules);
312 list_add_rcu(&nentry->list, &audit_inode_hash[h]);
313 list_replace(&oentry->rule.list,
317 audit_watch_log_rule_change(r, owatch, "updated rules");
319 call_rcu(&oentry->rcu, audit_free_rule_rcu);
322 audit_remove_watch(owatch);
323 goto add_watch_to_parent; /* event applies to a single watch */
325 mutex_unlock(&audit_filter_mutex);
329 list_add(&nwatch->wlist, &parent->watches);
330 mutex_unlock(&audit_filter_mutex);
334 /* Remove all watches & rules associated with a parent that is going away. */
335 static void audit_remove_parent_watches(struct audit_parent *parent)
337 struct audit_watch *w, *nextw;
338 struct audit_krule *r, *nextr;
339 struct audit_entry *e;
341 mutex_lock(&audit_filter_mutex);
342 list_for_each_entry_safe(w, nextw, &parent->watches, wlist) {
343 list_for_each_entry_safe(r, nextr, &w->rules, rlist) {
344 e = container_of(r, struct audit_entry, rule);
345 audit_watch_log_rule_change(r, w, "remove rule");
348 list_del_rcu(&e->list);
349 call_rcu(&e->rcu, audit_free_rule_rcu);
351 audit_remove_watch(w);
353 mutex_unlock(&audit_filter_mutex);
355 fsnotify_destroy_mark(&parent->mark, audit_watch_group);
358 /* Get path information necessary for adding watches. */
359 static int audit_get_nd(struct audit_watch *watch, struct path *parent)
361 struct dentry *d = kern_path_locked(watch->path, parent);
364 mutex_unlock(&parent->dentry->d_inode->i_mutex);
366 /* update watch filter fields */
367 watch->dev = d->d_inode->i_sb->s_dev;
368 watch->ino = d->d_inode->i_ino;
374 /* Associate the given rule with an existing parent.
375 * Caller must hold audit_filter_mutex. */
376 static void audit_add_to_parent(struct audit_krule *krule,
377 struct audit_parent *parent)
379 struct audit_watch *w, *watch = krule->watch;
382 BUG_ON(!mutex_is_locked(&audit_filter_mutex));
384 list_for_each_entry(w, &parent->watches, wlist) {
385 if (strcmp(watch->path, w->path))
390 /* put krule's and initial refs to temporary watch */
391 audit_put_watch(watch);
392 audit_put_watch(watch);
395 krule->watch = watch = w;
400 audit_get_parent(parent);
401 watch->parent = parent;
403 list_add(&watch->wlist, &parent->watches);
405 list_add(&krule->rlist, &watch->rules);
408 /* Find a matching watch entry, or add this one.
409 * Caller must hold audit_filter_mutex. */
410 int audit_add_watch(struct audit_krule *krule, struct list_head **list)
412 struct audit_watch *watch = krule->watch;
413 struct audit_parent *parent;
414 struct path parent_path;
417 mutex_unlock(&audit_filter_mutex);
419 /* Avoid calling path_lookup under audit_filter_mutex. */
420 ret = audit_get_nd(watch, &parent_path);
422 /* caller expects mutex locked */
423 mutex_lock(&audit_filter_mutex);
428 /* either find an old parent or attach a new one */
429 parent = audit_find_parent(parent_path.dentry->d_inode);
431 parent = audit_init_parent(&parent_path);
432 if (IS_ERR(parent)) {
433 ret = PTR_ERR(parent);
438 audit_add_to_parent(krule, parent);
440 /* match get in audit_find_parent or audit_init_parent */
441 audit_put_parent(parent);
443 h = audit_hash_ino((u32)watch->ino);
444 *list = &audit_inode_hash[h];
446 path_put(&parent_path);
450 void audit_remove_watch_rule(struct audit_krule *krule)
452 struct audit_watch *watch = krule->watch;
453 struct audit_parent *parent = watch->parent;
455 list_del(&krule->rlist);
457 if (list_empty(&watch->rules)) {
458 audit_remove_watch(watch);
460 if (list_empty(&parent->watches)) {
461 audit_get_parent(parent);
462 fsnotify_destroy_mark(&parent->mark, audit_watch_group);
463 audit_put_parent(parent);
468 /* Update watch data in audit rules based on fsnotify events. */
469 static int audit_watch_handle_event(struct fsnotify_group *group,
470 struct inode *to_tell,
471 struct fsnotify_mark *inode_mark,
472 struct fsnotify_mark *vfsmount_mark,
473 u32 mask, void *data, int data_type,
474 const unsigned char *dname, u32 cookie)
477 struct audit_parent *parent;
479 parent = container_of(inode_mark, struct audit_parent, mark);
481 BUG_ON(group != audit_watch_group);
484 case (FSNOTIFY_EVENT_PATH):
485 inode = ((struct path *)data)->dentry->d_inode;
487 case (FSNOTIFY_EVENT_INODE):
488 inode = (struct inode *)data;
496 if (mask & (FS_CREATE|FS_MOVED_TO) && inode)
497 audit_update_watch(parent, dname, inode->i_sb->s_dev, inode->i_ino, 0);
498 else if (mask & (FS_DELETE|FS_MOVED_FROM))
499 audit_update_watch(parent, dname, (dev_t)-1, (unsigned long)-1, 1);
500 else if (mask & (FS_DELETE_SELF|FS_UNMOUNT|FS_MOVE_SELF))
501 audit_remove_parent_watches(parent);
506 static const struct fsnotify_ops audit_watch_fsnotify_ops = {
507 .handle_event = audit_watch_handle_event,
510 static int __init audit_watch_init(void)
512 audit_watch_group = fsnotify_alloc_group(&audit_watch_fsnotify_ops);
513 if (IS_ERR(audit_watch_group)) {
514 audit_watch_group = NULL;
515 audit_panic("cannot create audit fsnotify group");
519 device_initcall(audit_watch_init);