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 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 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
);
170 fsnotify_recalc_group_mask(audit_watch_group
);
175 /* Initialize a watch entry. */
176 static struct audit_watch
*audit_init_watch(char *path
)
178 struct audit_watch
*watch
;
180 watch
= kzalloc(sizeof(*watch
), GFP_KERNEL
);
181 if (unlikely(!watch
))
182 return ERR_PTR(-ENOMEM
);
184 INIT_LIST_HEAD(&watch
->rules
);
185 atomic_set(&watch
->count
, 1);
187 watch
->dev
= (dev_t
)-1;
188 watch
->ino
= (unsigned long)-1;
193 /* Translate a watch string to kernel respresentation. */
194 int audit_to_watch(struct audit_krule
*krule
, char *path
, int len
, u32 op
)
196 struct audit_watch
*watch
;
198 if (!audit_watch_group
)
201 if (path
[0] != '/' || path
[len
-1] == '/' ||
202 krule
->listnr
!= AUDIT_FILTER_EXIT
||
204 krule
->inode_f
|| krule
->watch
|| krule
->tree
)
207 watch
= audit_init_watch(path
);
209 return PTR_ERR(watch
);
211 audit_get_watch(watch
);
212 krule
->watch
= watch
;
217 /* Duplicate the given audit watch. The new watch's rules list is initialized
218 * to an empty list and wlist is undefined. */
219 static struct audit_watch
*audit_dupe_watch(struct audit_watch
*old
)
222 struct audit_watch
*new;
224 path
= kstrdup(old
->path
, GFP_KERNEL
);
226 return ERR_PTR(-ENOMEM
);
228 new = audit_init_watch(path
);
236 audit_get_parent(old
->parent
);
237 new->parent
= old
->parent
;
243 static void audit_watch_log_rule_change(struct audit_krule
*r
, struct audit_watch
*w
, char *op
)
246 struct audit_buffer
*ab
;
247 ab
= audit_log_start(NULL
, GFP_NOFS
, AUDIT_CONFIG_CHANGE
);
248 audit_log_format(ab
, "auid=%u ses=%u op=",
249 audit_get_loginuid(current
),
250 audit_get_sessionid(current
));
251 audit_log_string(ab
, op
);
252 audit_log_format(ab
, " path=");
253 audit_log_untrustedstring(ab
, w
->path
);
254 audit_log_key(ab
, r
->filterkey
);
255 audit_log_format(ab
, " list=%d res=1", r
->listnr
);
260 /* Update inode info in audit rules based on filesystem event. */
261 static void audit_update_watch(struct audit_parent
*parent
,
262 const char *dname
, dev_t dev
,
263 unsigned long ino
, unsigned invalidating
)
265 struct audit_watch
*owatch
, *nwatch
, *nextw
;
266 struct audit_krule
*r
, *nextr
;
267 struct audit_entry
*oentry
, *nentry
;
269 mutex_lock(&audit_filter_mutex
);
270 /* Run all of the watches on this parent looking for the one that
271 * matches the given dname */
272 list_for_each_entry_safe(owatch
, nextw
, &parent
->watches
, wlist
) {
273 if (audit_compare_dname_path(dname
, owatch
->path
, NULL
))
276 /* If the update involves invalidating rules, do the inode-based
277 * filtering now, so we don't omit records. */
278 if (invalidating
&& !audit_dummy_context())
279 audit_filter_inodes(current
, current
->audit_context
);
281 /* updating ino will likely change which audit_hash_list we
282 * are on so we need a new watch for the new list */
283 nwatch
= audit_dupe_watch(owatch
);
284 if (IS_ERR(nwatch
)) {
285 mutex_unlock(&audit_filter_mutex
);
286 audit_panic("error updating watch, skipping");
292 list_for_each_entry_safe(r
, nextr
, &owatch
->rules
, rlist
) {
294 oentry
= container_of(r
, struct audit_entry
, rule
);
295 list_del(&oentry
->rule
.rlist
);
296 list_del_rcu(&oentry
->list
);
298 nentry
= audit_dupe_rule(&oentry
->rule
);
299 if (IS_ERR(nentry
)) {
300 list_del(&oentry
->rule
.list
);
301 audit_panic("error updating watch, removing");
303 int h
= audit_hash_ino((u32
)ino
);
306 * nentry->rule.watch == oentry->rule.watch so
307 * we must drop that reference and set it to our
310 audit_put_watch(nentry
->rule
.watch
);
311 audit_get_watch(nwatch
);
312 nentry
->rule
.watch
= nwatch
;
313 list_add(&nentry
->rule
.rlist
, &nwatch
->rules
);
314 list_add_rcu(&nentry
->list
, &audit_inode_hash
[h
]);
315 list_replace(&oentry
->rule
.list
,
319 audit_watch_log_rule_change(r
, owatch
, "updated rules");
321 call_rcu(&oentry
->rcu
, audit_free_rule_rcu
);
324 audit_remove_watch(owatch
);
325 goto add_watch_to_parent
; /* event applies to a single watch */
327 mutex_unlock(&audit_filter_mutex
);
331 list_add(&nwatch
->wlist
, &parent
->watches
);
332 mutex_unlock(&audit_filter_mutex
);
336 /* Remove all watches & rules associated with a parent that is going away. */
337 static void audit_remove_parent_watches(struct audit_parent
*parent
)
339 struct audit_watch
*w
, *nextw
;
340 struct audit_krule
*r
, *nextr
;
341 struct audit_entry
*e
;
343 mutex_lock(&audit_filter_mutex
);
344 list_for_each_entry_safe(w
, nextw
, &parent
->watches
, wlist
) {
345 list_for_each_entry_safe(r
, nextr
, &w
->rules
, rlist
) {
346 e
= container_of(r
, struct audit_entry
, rule
);
347 audit_watch_log_rule_change(r
, w
, "remove rule");
350 list_del_rcu(&e
->list
);
351 call_rcu(&e
->rcu
, audit_free_rule_rcu
);
353 audit_remove_watch(w
);
355 mutex_unlock(&audit_filter_mutex
);
357 fsnotify_destroy_mark_by_entry(&parent
->mark
);
359 fsnotify_recalc_group_mask(audit_watch_group
);
363 /* Get path information necessary for adding watches. */
364 static int audit_get_nd(char *path
, struct nameidata
**ndp
, struct nameidata
**ndw
)
366 struct nameidata
*ndparent
, *ndwatch
;
369 ndparent
= kmalloc(sizeof(*ndparent
), GFP_KERNEL
);
370 if (unlikely(!ndparent
))
373 ndwatch
= kmalloc(sizeof(*ndwatch
), GFP_KERNEL
);
374 if (unlikely(!ndwatch
)) {
379 err
= path_lookup(path
, LOOKUP_PARENT
, ndparent
);
386 err
= path_lookup(path
, 0, ndwatch
);
398 /* Release resources used for watch path information. */
399 static void audit_put_nd(struct nameidata
*ndp
, struct nameidata
*ndw
)
402 path_put(&ndp
->path
);
406 path_put(&ndw
->path
);
411 /* Associate the given rule with an existing parent.
412 * Caller must hold audit_filter_mutex. */
413 static void audit_add_to_parent(struct audit_krule
*krule
,
414 struct audit_parent
*parent
)
416 struct audit_watch
*w
, *watch
= krule
->watch
;
419 BUG_ON(!mutex_is_locked(&audit_filter_mutex
));
421 list_for_each_entry(w
, &parent
->watches
, wlist
) {
422 if (strcmp(watch
->path
, w
->path
))
427 /* put krule's and initial refs to temporary watch */
428 audit_put_watch(watch
);
429 audit_put_watch(watch
);
432 krule
->watch
= watch
= w
;
437 audit_get_parent(parent
);
438 watch
->parent
= parent
;
440 list_add(&watch
->wlist
, &parent
->watches
);
442 list_add(&krule
->rlist
, &watch
->rules
);
445 /* Find a matching watch entry, or add this one.
446 * Caller must hold audit_filter_mutex. */
447 int audit_add_watch(struct audit_krule
*krule
, struct list_head
**list
)
449 struct audit_watch
*watch
= krule
->watch
;
450 struct audit_parent
*parent
;
451 struct nameidata
*ndp
= NULL
, *ndw
= NULL
;
454 mutex_unlock(&audit_filter_mutex
);
456 /* Avoid calling path_lookup under audit_filter_mutex. */
457 ret
= audit_get_nd(watch
->path
, &ndp
, &ndw
);
459 /* caller expects mutex locked */
460 mutex_lock(&audit_filter_mutex
);
464 mutex_lock(&audit_filter_mutex
);
466 /* update watch filter fields */
468 watch
->dev
= ndw
->path
.dentry
->d_inode
->i_sb
->s_dev
;
469 watch
->ino
= ndw
->path
.dentry
->d_inode
->i_ino
;
472 /* either find an old parent or attach a new one */
473 parent
= audit_find_parent(ndp
->path
.dentry
->d_inode
);
475 parent
= audit_init_parent(ndp
);
476 if (IS_ERR(parent
)) {
477 ret
= PTR_ERR(parent
);
482 audit_add_to_parent(krule
, parent
);
484 /* match get in audit_find_parent or audit_init_parent */
485 audit_put_parent(parent
);
487 h
= audit_hash_ino((u32
)watch
->ino
);
488 *list
= &audit_inode_hash
[h
];
490 audit_put_nd(ndp
, ndw
); /* NULL args OK */
495 void audit_remove_watch_rule(struct audit_krule
*krule
)
497 struct audit_watch
*watch
= krule
->watch
;
498 struct audit_parent
*parent
= watch
->parent
;
500 list_del(&krule
->rlist
);
502 if (list_empty(&watch
->rules
)) {
503 audit_remove_watch(watch
);
505 if (list_empty(&parent
->watches
)) {
506 audit_get_parent(parent
);
507 fsnotify_destroy_mark_by_entry(&parent
->mark
);
508 audit_put_parent(parent
);
512 fsnotify_recalc_group_mask(audit_watch_group
);
516 static bool audit_watch_should_send_event(struct fsnotify_group
*group
, struct inode
*inode
,
517 struct vfsmount
*mnt
, __u32 mask
, void *data
,
520 struct fsnotify_mark
*entry
;
523 spin_lock(&inode
->i_lock
);
524 entry
= fsnotify_find_mark_entry(group
, inode
);
525 spin_unlock(&inode
->i_lock
);
529 mask
= (mask
& ~FS_EVENT_ON_CHILD
);
530 send
= (entry
->mask
& mask
);
532 /* find took a reference */
533 fsnotify_put_mark(entry
);
538 /* Update watch data in audit rules based on fsnotify events. */
539 static int audit_watch_handle_event(struct fsnotify_group
*group
, struct fsnotify_event
*event
)
542 __u32 mask
= event
->mask
;
543 const char *dname
= event
->file_name
;
544 struct audit_parent
*parent
;
546 BUG_ON(group
!= audit_watch_group
);
548 parent
= audit_find_parent(event
->to_tell
);
549 if (unlikely(!parent
))
552 switch (event
->data_type
) {
553 case (FSNOTIFY_EVENT_PATH
):
554 inode
= event
->path
.dentry
->d_inode
;
556 case (FSNOTIFY_EVENT_INODE
):
557 inode
= event
->inode
;
565 if (mask
& (FS_CREATE
|FS_MOVED_TO
) && inode
)
566 audit_update_watch(parent
, dname
, inode
->i_sb
->s_dev
, inode
->i_ino
, 0);
567 else if (mask
& (FS_DELETE
|FS_MOVED_FROM
))
568 audit_update_watch(parent
, dname
, (dev_t
)-1, (unsigned long)-1, 1);
569 else if (mask
& (FS_DELETE_SELF
|FS_UNMOUNT
|FS_MOVE_SELF
))
570 audit_remove_parent_watches(parent
);
571 /* moved put_inotify_watch to freeing mark */
573 /* matched the ref taken by audit_find_parent */
574 audit_put_parent(parent
);
579 static const struct fsnotify_ops audit_watch_fsnotify_ops
= {
580 .should_send_event
= audit_watch_should_send_event
,
581 .handle_event
= audit_watch_handle_event
,
582 .free_group_priv
= NULL
,
583 .freeing_mark
= NULL
,
584 .free_event_priv
= NULL
,
587 static int __init
audit_watch_init(void)
589 audit_watch_group
= fsnotify_alloc_group(&audit_watch_fsnotify_ops
);
590 if (IS_ERR(audit_watch_group
)) {
591 audit_watch_group
= NULL
;
592 audit_panic("cannot create audit fsnotify group");
596 device_initcall(audit_watch_init
);