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_entry mark
; /* fsnotify mark on the inode */
62 /* fsnotify handle. */
63 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
*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
*entry
;
104 spin_lock(&inode
->i_lock
);
105 entry
= fsnotify_find_mark_entry(audit_watch_group
, inode
);
106 spin_unlock(&inode
->i_lock
);
109 parent
= container_of(entry
, struct audit_parent
, mark
);
114 void audit_get_watch(struct audit_watch
*watch
)
116 atomic_inc(&watch
->count
);
119 void audit_put_watch(struct audit_watch
*watch
)
121 if (atomic_dec_and_test(&watch
->count
)) {
122 WARN_ON(watch
->parent
);
123 WARN_ON(!list_empty(&watch
->rules
));
129 void audit_remove_watch(struct audit_watch
*watch
)
131 list_del(&watch
->wlist
);
132 audit_put_parent(watch
->parent
);
133 watch
->parent
= NULL
;
134 audit_put_watch(watch
); /* match initial get */
137 char *audit_watch_path(struct audit_watch
*watch
)
142 int audit_watch_compare(struct audit_watch
*watch
, unsigned long ino
, dev_t dev
)
144 return (watch
->ino
!= (unsigned long)-1) &&
145 (watch
->ino
== ino
) &&
149 /* Initialize a parent watch entry. */
150 static struct audit_parent
*audit_init_parent(struct nameidata
*ndp
)
152 struct inode
*inode
= ndp
->path
.dentry
->d_inode
;
153 struct audit_parent
*parent
;
156 parent
= kzalloc(sizeof(*parent
), GFP_KERNEL
);
157 if (unlikely(!parent
))
158 return ERR_PTR(-ENOMEM
);
160 INIT_LIST_HEAD(&parent
->watches
);
162 fsnotify_init_mark(&parent
->mark
, audit_watch_free_mark
);
163 parent
->mark
.mask
= AUDIT_FS_WATCH
;
164 ret
= fsnotify_add_mark(&parent
->mark
, audit_watch_group
, inode
, 0);
166 audit_free_parent(parent
);
173 /* Initialize a watch entry. */
174 static struct audit_watch
*audit_init_watch(char *path
)
176 struct audit_watch
*watch
;
178 watch
= kzalloc(sizeof(*watch
), GFP_KERNEL
);
179 if (unlikely(!watch
))
180 return ERR_PTR(-ENOMEM
);
182 INIT_LIST_HEAD(&watch
->rules
);
183 atomic_set(&watch
->count
, 1);
185 watch
->dev
= (dev_t
)-1;
186 watch
->ino
= (unsigned long)-1;
191 /* Translate a watch string to kernel respresentation. */
192 int audit_to_watch(struct audit_krule
*krule
, char *path
, int len
, u32 op
)
194 struct audit_watch
*watch
;
196 if (!audit_watch_group
)
199 if (path
[0] != '/' || path
[len
-1] == '/' ||
200 krule
->listnr
!= AUDIT_FILTER_EXIT
||
202 krule
->inode_f
|| krule
->watch
|| krule
->tree
)
205 watch
= audit_init_watch(path
);
207 return PTR_ERR(watch
);
209 audit_get_watch(watch
);
210 krule
->watch
= watch
;
215 /* Duplicate the given audit watch. The new watch's rules list is initialized
216 * to an empty list and wlist is undefined. */
217 static struct audit_watch
*audit_dupe_watch(struct audit_watch
*old
)
220 struct audit_watch
*new;
222 path
= kstrdup(old
->path
, GFP_KERNEL
);
224 return ERR_PTR(-ENOMEM
);
226 new = audit_init_watch(path
);
234 audit_get_parent(old
->parent
);
235 new->parent
= old
->parent
;
241 static void audit_watch_log_rule_change(struct audit_krule
*r
, struct audit_watch
*w
, char *op
)
244 struct audit_buffer
*ab
;
245 ab
= audit_log_start(NULL
, GFP_NOFS
, AUDIT_CONFIG_CHANGE
);
246 audit_log_format(ab
, "auid=%u ses=%u op=",
247 audit_get_loginuid(current
),
248 audit_get_sessionid(current
));
249 audit_log_string(ab
, op
);
250 audit_log_format(ab
, " path=");
251 audit_log_untrustedstring(ab
, w
->path
);
252 audit_log_key(ab
, r
->filterkey
);
253 audit_log_format(ab
, " list=%d res=1", r
->listnr
);
258 /* Update inode info in audit rules based on filesystem event. */
259 static void audit_update_watch(struct audit_parent
*parent
,
260 const char *dname
, dev_t dev
,
261 unsigned long ino
, unsigned invalidating
)
263 struct audit_watch
*owatch
, *nwatch
, *nextw
;
264 struct audit_krule
*r
, *nextr
;
265 struct audit_entry
*oentry
, *nentry
;
267 mutex_lock(&audit_filter_mutex
);
268 /* Run all of the watches on this parent looking for the one that
269 * matches the given dname */
270 list_for_each_entry_safe(owatch
, nextw
, &parent
->watches
, wlist
) {
271 if (audit_compare_dname_path(dname
, owatch
->path
, NULL
))
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_by_entry(&parent
->mark
);
358 /* Get path information necessary for adding watches. */
359 static int audit_get_nd(char *path
, struct nameidata
**ndp
, struct nameidata
**ndw
)
361 struct nameidata
*ndparent
, *ndwatch
;
364 ndparent
= kmalloc(sizeof(*ndparent
), GFP_KERNEL
);
365 if (unlikely(!ndparent
))
368 ndwatch
= kmalloc(sizeof(*ndwatch
), GFP_KERNEL
);
369 if (unlikely(!ndwatch
)) {
374 err
= path_lookup(path
, LOOKUP_PARENT
, ndparent
);
381 err
= path_lookup(path
, 0, ndwatch
);
393 /* Release resources used for watch path information. */
394 static void audit_put_nd(struct nameidata
*ndp
, struct nameidata
*ndw
)
397 path_put(&ndp
->path
);
401 path_put(&ndw
->path
);
406 /* Associate the given rule with an existing parent.
407 * Caller must hold audit_filter_mutex. */
408 static void audit_add_to_parent(struct audit_krule
*krule
,
409 struct audit_parent
*parent
)
411 struct audit_watch
*w
, *watch
= krule
->watch
;
414 BUG_ON(!mutex_is_locked(&audit_filter_mutex
));
416 list_for_each_entry(w
, &parent
->watches
, wlist
) {
417 if (strcmp(watch
->path
, w
->path
))
422 /* put krule's and initial refs to temporary watch */
423 audit_put_watch(watch
);
424 audit_put_watch(watch
);
427 krule
->watch
= watch
= w
;
432 audit_get_parent(parent
);
433 watch
->parent
= parent
;
435 list_add(&watch
->wlist
, &parent
->watches
);
437 list_add(&krule
->rlist
, &watch
->rules
);
440 /* Find a matching watch entry, or add this one.
441 * Caller must hold audit_filter_mutex. */
442 int audit_add_watch(struct audit_krule
*krule
, struct list_head
**list
)
444 struct audit_watch
*watch
= krule
->watch
;
445 struct audit_parent
*parent
;
446 struct nameidata
*ndp
= NULL
, *ndw
= NULL
;
449 mutex_unlock(&audit_filter_mutex
);
451 /* Avoid calling path_lookup under audit_filter_mutex. */
452 ret
= audit_get_nd(watch
->path
, &ndp
, &ndw
);
454 /* caller expects mutex locked */
455 mutex_lock(&audit_filter_mutex
);
459 mutex_lock(&audit_filter_mutex
);
461 /* update watch filter fields */
463 watch
->dev
= ndw
->path
.dentry
->d_inode
->i_sb
->s_dev
;
464 watch
->ino
= ndw
->path
.dentry
->d_inode
->i_ino
;
467 /* either find an old parent or attach a new one */
468 parent
= audit_find_parent(ndp
->path
.dentry
->d_inode
);
470 parent
= audit_init_parent(ndp
);
471 if (IS_ERR(parent
)) {
472 ret
= PTR_ERR(parent
);
477 audit_add_to_parent(krule
, parent
);
479 /* match get in audit_find_parent or audit_init_parent */
480 audit_put_parent(parent
);
482 h
= audit_hash_ino((u32
)watch
->ino
);
483 *list
= &audit_inode_hash
[h
];
485 audit_put_nd(ndp
, ndw
); /* NULL args OK */
490 void audit_remove_watch_rule(struct audit_krule
*krule
)
492 struct audit_watch
*watch
= krule
->watch
;
493 struct audit_parent
*parent
= watch
->parent
;
495 list_del(&krule
->rlist
);
497 if (list_empty(&watch
->rules
)) {
498 audit_remove_watch(watch
);
500 if (list_empty(&parent
->watches
)) {
501 audit_get_parent(parent
);
502 fsnotify_destroy_mark_by_entry(&parent
->mark
);
503 audit_put_parent(parent
);
508 static bool audit_watch_should_send_event(struct fsnotify_group
*group
, struct inode
*inode
,
509 __u32 mask
, void *data
, int data_type
)
511 struct fsnotify_mark_entry
*entry
;
514 spin_lock(&inode
->i_lock
);
515 entry
= fsnotify_find_mark_entry(group
, inode
);
516 spin_unlock(&inode
->i_lock
);
520 mask
= (mask
& ~FS_EVENT_ON_CHILD
);
521 send
= (entry
->mask
& mask
);
523 /* find took a reference */
524 fsnotify_put_mark(entry
);
529 /* Update watch data in audit rules based on fsnotify events. */
530 static int audit_watch_handle_event(struct fsnotify_group
*group
, struct fsnotify_event
*event
)
533 __u32 mask
= event
->mask
;
534 const char *dname
= event
->file_name
;
535 struct audit_parent
*parent
;
537 BUG_ON(group
!= audit_watch_group
);
539 parent
= audit_find_parent(event
->to_tell
);
540 if (unlikely(!parent
))
543 switch (event
->data_type
) {
544 case (FSNOTIFY_EVENT_PATH
):
545 inode
= event
->path
.dentry
->d_inode
;
547 case (FSNOTIFY_EVENT_INODE
):
548 inode
= event
->inode
;
556 if (mask
& (FS_CREATE
|FS_MOVED_TO
) && inode
)
557 audit_update_watch(parent
, dname
, inode
->i_sb
->s_dev
, inode
->i_ino
, 0);
558 else if (mask
& (FS_DELETE
|FS_MOVED_FROM
))
559 audit_update_watch(parent
, dname
, (dev_t
)-1, (unsigned long)-1, 1);
560 else if (mask
& (FS_DELETE_SELF
|FS_UNMOUNT
|FS_MOVE_SELF
))
561 audit_remove_parent_watches(parent
);
562 /* moved put_inotify_watch to freeing mark */
564 /* matched the ref taken by audit_find_parent */
565 audit_put_parent(parent
);
570 static const struct fsnotify_ops audit_watch_fsnotify_ops
= {
571 .should_send_event
= audit_watch_should_send_event
,
572 .handle_event
= audit_watch_handle_event
,
573 .free_group_priv
= NULL
,
574 .freeing_mark
= NULL
,
575 .free_event_priv
= NULL
,
578 static int __init
audit_watch_init(void)
580 audit_watch_group
= fsnotify_obtain_group(AUDIT_FS_WATCH
,
581 &audit_watch_fsnotify_ops
);
582 if (IS_ERR(audit_watch_group
)) {
583 audit_watch_group
= NULL
;
584 audit_panic("cannot create audit fsnotify group");
588 device_initcall(audit_watch_init
);