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/file.h>
23 #include <linux/kernel.h>
24 #include <linux/audit.h>
25 #include <linux/kthread.h>
26 #include <linux/mutex.h>
28 #include <linux/fsnotify_backend.h>
29 #include <linux/namei.h>
30 #include <linux/netlink.h>
31 #include <linux/refcount.h>
32 #include <linux/sched.h>
33 #include <linux/slab.h>
34 #include <linux/security.h>
40 * audit_parent: lifetime is from audit_init_parent() to receipt of an FS_IGNORED
41 * event. Each audit_watch holds a reference to its associated parent.
43 * audit_watch: if added to lists, lifetime is from audit_init_watch() to
44 * audit_remove_watch(). Additionally, an audit_watch may exist
45 * temporarily to assist in searching existing filter data. Each
46 * audit_krule holds a reference to its associated watch.
50 refcount_t count
; /* reference count */
51 dev_t dev
; /* associated superblock device */
52 char *path
; /* insertion path */
53 unsigned long ino
; /* associated inode number */
54 struct audit_parent
*parent
; /* associated parent */
55 struct list_head wlist
; /* entry in parent->watches list */
56 struct list_head rules
; /* anchor for krule->rlist */
60 struct list_head watches
; /* anchor for audit_watch->wlist */
61 struct fsnotify_mark mark
; /* fsnotify mark on the inode */
64 /* fsnotify handle. */
65 static struct fsnotify_group
*audit_watch_group
;
67 /* fsnotify events we care about. */
68 #define AUDIT_FS_WATCH (FS_MOVE | FS_CREATE | FS_DELETE | FS_DELETE_SELF |\
69 FS_MOVE_SELF | FS_EVENT_ON_CHILD | FS_UNMOUNT)
71 static void audit_free_parent(struct audit_parent
*parent
)
73 WARN_ON(!list_empty(&parent
->watches
));
77 static void audit_watch_free_mark(struct fsnotify_mark
*entry
)
79 struct audit_parent
*parent
;
81 parent
= container_of(entry
, struct audit_parent
, mark
);
82 audit_free_parent(parent
);
85 static void audit_get_parent(struct audit_parent
*parent
)
88 fsnotify_get_mark(&parent
->mark
);
91 static void audit_put_parent(struct audit_parent
*parent
)
94 fsnotify_put_mark(&parent
->mark
);
98 * Find and return the audit_parent on the given inode. If found a reference
99 * is taken on this parent.
101 static inline struct audit_parent
*audit_find_parent(struct inode
*inode
)
103 struct audit_parent
*parent
= NULL
;
104 struct fsnotify_mark
*entry
;
106 entry
= fsnotify_find_mark(&inode
->i_fsnotify_marks
, audit_watch_group
);
108 parent
= container_of(entry
, struct audit_parent
, mark
);
113 void audit_get_watch(struct audit_watch
*watch
)
115 refcount_inc(&watch
->count
);
118 void audit_put_watch(struct audit_watch
*watch
)
120 if (refcount_dec_and_test(&watch
->count
)) {
121 WARN_ON(watch
->parent
);
122 WARN_ON(!list_empty(&watch
->rules
));
128 static void audit_remove_watch(struct audit_watch
*watch
)
130 list_del(&watch
->wlist
);
131 audit_put_parent(watch
->parent
);
132 watch
->parent
= NULL
;
133 audit_put_watch(watch
); /* match initial get */
136 char *audit_watch_path(struct audit_watch
*watch
)
141 int audit_watch_compare(struct audit_watch
*watch
, unsigned long ino
, dev_t dev
)
143 return (watch
->ino
!= AUDIT_INO_UNSET
) &&
144 (watch
->ino
== ino
) &&
148 /* Initialize a parent watch entry. */
149 static struct audit_parent
*audit_init_parent(struct path
*path
)
151 struct inode
*inode
= d_backing_inode(path
->dentry
);
152 struct audit_parent
*parent
;
155 parent
= kzalloc(sizeof(*parent
), GFP_KERNEL
);
156 if (unlikely(!parent
))
157 return ERR_PTR(-ENOMEM
);
159 INIT_LIST_HEAD(&parent
->watches
);
161 fsnotify_init_mark(&parent
->mark
, audit_watch_group
);
162 parent
->mark
.mask
= AUDIT_FS_WATCH
;
163 ret
= fsnotify_add_inode_mark(&parent
->mark
, inode
, 0);
165 audit_free_parent(parent
);
172 /* Initialize a watch entry. */
173 static struct audit_watch
*audit_init_watch(char *path
)
175 struct audit_watch
*watch
;
177 watch
= kzalloc(sizeof(*watch
), GFP_KERNEL
);
178 if (unlikely(!watch
))
179 return ERR_PTR(-ENOMEM
);
181 INIT_LIST_HEAD(&watch
->rules
);
182 refcount_set(&watch
->count
, 1);
184 watch
->dev
= AUDIT_DEV_UNSET
;
185 watch
->ino
= AUDIT_INO_UNSET
;
190 /* Translate a watch string to kernel representation. */
191 int audit_to_watch(struct audit_krule
*krule
, char *path
, int len
, u32 op
)
193 struct audit_watch
*watch
;
195 if (!audit_watch_group
)
198 if (path
[0] != '/' || path
[len
-1] == '/' ||
199 krule
->listnr
!= AUDIT_FILTER_EXIT
||
201 krule
->inode_f
|| krule
->watch
|| krule
->tree
)
204 watch
= audit_init_watch(path
);
206 return PTR_ERR(watch
);
208 krule
->watch
= watch
;
213 /* Duplicate the given audit watch. The new watch's rules list is initialized
214 * to an empty list and wlist is undefined. */
215 static struct audit_watch
*audit_dupe_watch(struct audit_watch
*old
)
218 struct audit_watch
*new;
220 path
= kstrdup(old
->path
, GFP_KERNEL
);
222 return ERR_PTR(-ENOMEM
);
224 new = audit_init_watch(path
);
232 audit_get_parent(old
->parent
);
233 new->parent
= old
->parent
;
239 static void audit_watch_log_rule_change(struct audit_krule
*r
, struct audit_watch
*w
, char *op
)
241 struct audit_buffer
*ab
;
245 ab
= audit_log_start(NULL
, GFP_NOFS
, AUDIT_CONFIG_CHANGE
);
248 audit_log_session_info(ab
);
249 audit_log_format(ab
, "op=%s path=", op
);
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
);
256 /* Update inode info in audit rules based on filesystem event. */
257 static void audit_update_watch(struct audit_parent
*parent
,
258 const char *dname
, dev_t dev
,
259 unsigned long ino
, unsigned invalidating
)
261 struct audit_watch
*owatch
, *nwatch
, *nextw
;
262 struct audit_krule
*r
, *nextr
;
263 struct audit_entry
*oentry
, *nentry
;
265 mutex_lock(&audit_filter_mutex
);
266 /* Run all of the watches on this parent looking for the one that
267 * matches the given dname */
268 list_for_each_entry_safe(owatch
, nextw
, &parent
->watches
, wlist
) {
269 if (audit_compare_dname_path(dname
, owatch
->path
,
273 /* If the update involves invalidating rules, do the inode-based
274 * filtering now, so we don't omit records. */
275 if (invalidating
&& !audit_dummy_context())
276 audit_filter_inodes(current
, audit_context());
278 /* updating ino will likely change which audit_hash_list we
279 * are on so we need a new watch for the new list */
280 nwatch
= audit_dupe_watch(owatch
);
281 if (IS_ERR(nwatch
)) {
282 mutex_unlock(&audit_filter_mutex
);
283 audit_panic("error updating watch, skipping");
289 list_for_each_entry_safe(r
, nextr
, &owatch
->rules
, rlist
) {
291 oentry
= container_of(r
, struct audit_entry
, rule
);
292 list_del(&oentry
->rule
.rlist
);
293 list_del_rcu(&oentry
->list
);
295 nentry
= audit_dupe_rule(&oentry
->rule
);
296 if (IS_ERR(nentry
)) {
297 list_del(&oentry
->rule
.list
);
298 audit_panic("error updating watch, removing");
300 int h
= audit_hash_ino((u32
)ino
);
303 * nentry->rule.watch == oentry->rule.watch so
304 * we must drop that reference and set it to our
307 audit_put_watch(nentry
->rule
.watch
);
308 audit_get_watch(nwatch
);
309 nentry
->rule
.watch
= nwatch
;
310 list_add(&nentry
->rule
.rlist
, &nwatch
->rules
);
311 list_add_rcu(&nentry
->list
, &audit_inode_hash
[h
]);
312 list_replace(&oentry
->rule
.list
,
315 if (oentry
->rule
.exe
)
316 audit_remove_mark(oentry
->rule
.exe
);
318 audit_watch_log_rule_change(r
, owatch
, "updated_rules");
320 call_rcu(&oentry
->rcu
, audit_free_rule_rcu
);
323 audit_remove_watch(owatch
);
324 goto add_watch_to_parent
; /* event applies to a single watch */
326 mutex_unlock(&audit_filter_mutex
);
330 list_add(&nwatch
->wlist
, &parent
->watches
);
331 mutex_unlock(&audit_filter_mutex
);
335 /* Remove all watches & rules associated with a parent that is going away. */
336 static void audit_remove_parent_watches(struct audit_parent
*parent
)
338 struct audit_watch
*w
, *nextw
;
339 struct audit_krule
*r
, *nextr
;
340 struct audit_entry
*e
;
342 mutex_lock(&audit_filter_mutex
);
343 list_for_each_entry_safe(w
, nextw
, &parent
->watches
, wlist
) {
344 list_for_each_entry_safe(r
, nextr
, &w
->rules
, rlist
) {
345 e
= container_of(r
, struct audit_entry
, rule
);
346 audit_watch_log_rule_change(r
, w
, "remove_rule");
348 audit_remove_mark(e
->rule
.exe
);
351 list_del_rcu(&e
->list
);
352 call_rcu(&e
->rcu
, audit_free_rule_rcu
);
354 audit_remove_watch(w
);
356 mutex_unlock(&audit_filter_mutex
);
358 fsnotify_destroy_mark(&parent
->mark
, audit_watch_group
);
361 /* Get path information necessary for adding watches. */
362 static int audit_get_nd(struct audit_watch
*watch
, struct path
*parent
)
364 struct dentry
*d
= kern_path_locked(watch
->path
, parent
);
367 inode_unlock(d_backing_inode(parent
->dentry
));
368 if (d_is_positive(d
)) {
369 /* update watch filter fields */
370 watch
->dev
= d
->d_sb
->s_dev
;
371 watch
->ino
= d_backing_inode(d
)->i_ino
;
377 /* Associate the given rule with an existing parent.
378 * Caller must hold audit_filter_mutex. */
379 static void audit_add_to_parent(struct audit_krule
*krule
,
380 struct audit_parent
*parent
)
382 struct audit_watch
*w
, *watch
= krule
->watch
;
385 BUG_ON(!mutex_is_locked(&audit_filter_mutex
));
387 list_for_each_entry(w
, &parent
->watches
, wlist
) {
388 if (strcmp(watch
->path
, w
->path
))
393 /* put krule's ref to temporary watch */
394 audit_put_watch(watch
);
397 krule
->watch
= watch
= w
;
399 audit_put_parent(parent
);
404 watch
->parent
= parent
;
406 audit_get_watch(watch
);
407 list_add(&watch
->wlist
, &parent
->watches
);
409 list_add(&krule
->rlist
, &watch
->rules
);
412 /* Find a matching watch entry, or add this one.
413 * Caller must hold audit_filter_mutex. */
414 int audit_add_watch(struct audit_krule
*krule
, struct list_head
**list
)
416 struct audit_watch
*watch
= krule
->watch
;
417 struct audit_parent
*parent
;
418 struct path parent_path
;
422 * When we will be calling audit_add_to_parent, krule->watch might have
423 * been updated and watch might have been freed.
424 * So we need to keep a reference of watch.
426 audit_get_watch(watch
);
428 mutex_unlock(&audit_filter_mutex
);
430 /* Avoid calling path_lookup under audit_filter_mutex. */
431 ret
= audit_get_nd(watch
, &parent_path
);
433 /* caller expects mutex locked */
434 mutex_lock(&audit_filter_mutex
);
437 audit_put_watch(watch
);
441 /* either find an old parent or attach a new one */
442 parent
= audit_find_parent(d_backing_inode(parent_path
.dentry
));
444 parent
= audit_init_parent(&parent_path
);
445 if (IS_ERR(parent
)) {
446 ret
= PTR_ERR(parent
);
451 audit_add_to_parent(krule
, parent
);
453 h
= audit_hash_ino((u32
)watch
->ino
);
454 *list
= &audit_inode_hash
[h
];
456 path_put(&parent_path
);
457 audit_put_watch(watch
);
461 void audit_remove_watch_rule(struct audit_krule
*krule
)
463 struct audit_watch
*watch
= krule
->watch
;
464 struct audit_parent
*parent
= watch
->parent
;
466 list_del(&krule
->rlist
);
468 if (list_empty(&watch
->rules
)) {
470 * audit_remove_watch() drops our reference to 'parent' which
471 * can get freed. Grab our own reference to be safe.
473 audit_get_parent(parent
);
474 audit_remove_watch(watch
);
475 if (list_empty(&parent
->watches
))
476 fsnotify_destroy_mark(&parent
->mark
, audit_watch_group
);
477 audit_put_parent(parent
);
481 /* Update watch data in audit rules based on fsnotify events. */
482 static int audit_watch_handle_event(struct fsnotify_group
*group
,
483 struct inode
*to_tell
,
484 u32 mask
, const void *data
, int data_type
,
485 const unsigned char *dname
, u32 cookie
,
486 struct fsnotify_iter_info
*iter_info
)
488 struct fsnotify_mark
*inode_mark
= fsnotify_iter_inode_mark(iter_info
);
489 const struct inode
*inode
;
490 struct audit_parent
*parent
;
492 parent
= container_of(inode_mark
, struct audit_parent
, mark
);
494 BUG_ON(group
!= audit_watch_group
);
497 case (FSNOTIFY_EVENT_PATH
):
498 inode
= d_backing_inode(((const struct path
*)data
)->dentry
);
500 case (FSNOTIFY_EVENT_INODE
):
501 inode
= (const struct inode
*)data
;
509 if (mask
& (FS_CREATE
|FS_MOVED_TO
) && inode
)
510 audit_update_watch(parent
, dname
, inode
->i_sb
->s_dev
, inode
->i_ino
, 0);
511 else if (mask
& (FS_DELETE
|FS_MOVED_FROM
))
512 audit_update_watch(parent
, dname
, AUDIT_DEV_UNSET
, AUDIT_INO_UNSET
, 1);
513 else if (mask
& (FS_DELETE_SELF
|FS_UNMOUNT
|FS_MOVE_SELF
))
514 audit_remove_parent_watches(parent
);
519 static const struct fsnotify_ops audit_watch_fsnotify_ops
= {
520 .handle_event
= audit_watch_handle_event
,
521 .free_mark
= audit_watch_free_mark
,
524 static int __init
audit_watch_init(void)
526 audit_watch_group
= fsnotify_alloc_group(&audit_watch_fsnotify_ops
);
527 if (IS_ERR(audit_watch_group
)) {
528 audit_watch_group
= NULL
;
529 audit_panic("cannot create audit fsnotify group");
533 device_initcall(audit_watch_init
);
535 int audit_dupe_exe(struct audit_krule
*new, struct audit_krule
*old
)
537 struct audit_fsnotify_mark
*audit_mark
;
540 pathname
= kstrdup(audit_mark_path(old
->exe
), GFP_KERNEL
);
544 audit_mark
= audit_alloc_mark(new, pathname
, strlen(pathname
));
545 if (IS_ERR(audit_mark
)) {
547 return PTR_ERR(audit_mark
);
549 new->exe
= audit_mark
;
554 int audit_exe_compare(struct task_struct
*tsk
, struct audit_fsnotify_mark
*mark
)
556 struct file
*exe_file
;
560 exe_file
= get_task_exe_file(tsk
);
563 ino
= file_inode(exe_file
)->i_ino
;
564 dev
= file_inode(exe_file
)->i_sb
->s_dev
;
566 return audit_mark_compare(mark
, ino
, dev
);