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/namei.h>
28 #include <linux/netlink.h>
29 #include <linux/sched.h>
30 #include <linux/inotify.h>
31 #include <linux/security.h>
37 * audit_parent: lifetime is from audit_init_parent() to receipt of an IN_IGNORED
38 * event. Each audit_watch holds a reference to its associated parent.
40 * audit_watch: if added to lists, lifetime is from audit_init_watch() to
41 * audit_remove_watch(). Additionally, an audit_watch may exist
42 * temporarily to assist in searching existing filter data. Each
43 * audit_krule holds a reference to its associated watch.
47 atomic_t count; /* reference count */
48 char *path; /* insertion path */
49 dev_t dev; /* associated superblock device */
50 unsigned long ino; /* associated inode number */
51 struct audit_parent *parent; /* associated parent */
52 struct list_head wlist; /* entry in parent->watches list */
53 struct list_head rules; /* associated rules */
57 struct list_head ilist; /* entry in inotify registration list */
58 struct list_head watches; /* associated watches */
59 struct inotify_watch wdata; /* inotify watch data */
60 unsigned flags; /* status flags */
64 struct inotify_handle *audit_ih;
67 * audit_parent status flags:
69 * AUDIT_PARENT_INVALID - set anytime rules/watches are auto-removed due to
70 * a filesystem event to ensure we're adding audit watches to a valid parent.
71 * Technically not needed for IN_DELETE_SELF or IN_UNMOUNT events, as we cannot
72 * receive them while we have nameidata, but must be used for IN_MOVE_SELF which
73 * we can receive while holding nameidata.
75 #define AUDIT_PARENT_INVALID 0x001
77 /* Inotify events we care about. */
78 #define AUDIT_IN_WATCH IN_MOVE|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF
80 static void audit_free_parent(struct inotify_watch *i_watch)
82 struct audit_parent *parent;
84 parent = container_of(i_watch, struct audit_parent, wdata);
85 WARN_ON(!list_empty(&parent->watches));
89 void audit_get_watch(struct audit_watch *watch)
91 atomic_inc(&watch->count);
94 void audit_put_watch(struct audit_watch *watch)
96 if (atomic_dec_and_test(&watch->count)) {
97 WARN_ON(watch->parent);
98 WARN_ON(!list_empty(&watch->rules));
104 void audit_remove_watch(struct audit_watch *watch)
106 list_del(&watch->wlist);
107 put_inotify_watch(&watch->parent->wdata);
108 watch->parent = NULL;
109 audit_put_watch(watch); /* match initial get */
112 char *audit_watch_path(struct audit_watch *watch)
117 struct list_head *audit_watch_rules(struct audit_watch *watch)
119 return &watch->rules;
122 unsigned long audit_watch_inode(struct audit_watch *watch)
127 dev_t audit_watch_dev(struct audit_watch *watch)
132 /* Initialize a parent watch entry. */
133 static struct audit_parent *audit_init_parent(struct nameidata *ndp)
135 struct audit_parent *parent;
138 parent = kzalloc(sizeof(*parent), GFP_KERNEL);
139 if (unlikely(!parent))
140 return ERR_PTR(-ENOMEM);
142 INIT_LIST_HEAD(&parent->watches);
145 inotify_init_watch(&parent->wdata);
146 /* grab a ref so inotify watch hangs around until we take audit_filter_mutex */
147 get_inotify_watch(&parent->wdata);
148 wd = inotify_add_watch(audit_ih, &parent->wdata,
149 ndp->path.dentry->d_inode, AUDIT_IN_WATCH);
151 audit_free_parent(&parent->wdata);
158 /* Initialize a watch entry. */
159 static struct audit_watch *audit_init_watch(char *path)
161 struct audit_watch *watch;
163 watch = kzalloc(sizeof(*watch), GFP_KERNEL);
164 if (unlikely(!watch))
165 return ERR_PTR(-ENOMEM);
167 INIT_LIST_HEAD(&watch->rules);
168 atomic_set(&watch->count, 1);
170 watch->dev = (dev_t)-1;
171 watch->ino = (unsigned long)-1;
176 /* Translate a watch string to kernel respresentation. */
177 int audit_to_watch(struct audit_krule *krule, char *path, int len, u32 op)
179 struct audit_watch *watch;
184 if (path[0] != '/' || path[len-1] == '/' ||
185 krule->listnr != AUDIT_FILTER_EXIT ||
187 krule->inode_f || krule->watch || krule->tree)
190 watch = audit_init_watch(path);
192 return PTR_ERR(watch);
194 audit_get_watch(watch);
195 krule->watch = watch;
200 /* Duplicate the given audit watch. The new watch's rules list is initialized
201 * to an empty list and wlist is undefined. */
202 static struct audit_watch *audit_dupe_watch(struct audit_watch *old)
205 struct audit_watch *new;
207 path = kstrdup(old->path, GFP_KERNEL);
209 return ERR_PTR(-ENOMEM);
211 new = audit_init_watch(path);
219 get_inotify_watch(&old->parent->wdata);
220 new->parent = old->parent;
226 static void audit_watch_log_rule_change(struct audit_krule *r, struct audit_watch *w, char *op)
229 struct audit_buffer *ab;
230 ab = audit_log_start(NULL, GFP_NOFS, AUDIT_CONFIG_CHANGE);
231 audit_log_format(ab, "auid=%u ses=%u op=",
232 audit_get_loginuid(current),
233 audit_get_sessionid(current));
234 audit_log_string(ab, op);
235 audit_log_format(ab, " path=");
236 audit_log_untrustedstring(ab, w->path);
237 audit_log_key(ab, r->filterkey);
238 audit_log_format(ab, " list=%d res=1", r->listnr);
243 /* Update inode info in audit rules based on filesystem event. */
244 static void audit_update_watch(struct audit_parent *parent,
245 const char *dname, dev_t dev,
246 unsigned long ino, unsigned invalidating)
248 struct audit_watch *owatch, *nwatch, *nextw;
249 struct audit_krule *r, *nextr;
250 struct audit_entry *oentry, *nentry;
252 mutex_lock(&audit_filter_mutex);
253 list_for_each_entry_safe(owatch, nextw, &parent->watches, wlist) {
254 if (audit_compare_dname_path(dname, owatch->path, NULL))
257 /* If the update involves invalidating rules, do the inode-based
258 * filtering now, so we don't omit records. */
259 if (invalidating && current->audit_context)
260 audit_filter_inodes(current, current->audit_context);
262 nwatch = audit_dupe_watch(owatch);
263 if (IS_ERR(nwatch)) {
264 mutex_unlock(&audit_filter_mutex);
265 audit_panic("error updating watch, skipping");
271 list_for_each_entry_safe(r, nextr, &owatch->rules, rlist) {
273 oentry = container_of(r, struct audit_entry, rule);
274 list_del(&oentry->rule.rlist);
275 list_del_rcu(&oentry->list);
277 nentry = audit_dupe_rule(&oentry->rule, nwatch);
278 if (IS_ERR(nentry)) {
279 list_del(&oentry->rule.list);
280 audit_panic("error updating watch, removing");
282 int h = audit_hash_ino((u32)ino);
283 list_add(&nentry->rule.rlist, &nwatch->rules);
284 list_add_rcu(&nentry->list, &audit_inode_hash[h]);
285 list_replace(&oentry->rule.list,
289 audit_watch_log_rule_change(r, owatch, "updated rules");
291 call_rcu(&oentry->rcu, audit_free_rule_rcu);
294 audit_remove_watch(owatch);
295 goto add_watch_to_parent; /* event applies to a single watch */
297 mutex_unlock(&audit_filter_mutex);
301 list_add(&nwatch->wlist, &parent->watches);
302 mutex_unlock(&audit_filter_mutex);
306 /* Remove all watches & rules associated with a parent that is going away. */
307 static void audit_remove_parent_watches(struct audit_parent *parent)
309 struct audit_watch *w, *nextw;
310 struct audit_krule *r, *nextr;
311 struct audit_entry *e;
313 mutex_lock(&audit_filter_mutex);
314 parent->flags |= AUDIT_PARENT_INVALID;
315 list_for_each_entry_safe(w, nextw, &parent->watches, wlist) {
316 list_for_each_entry_safe(r, nextr, &w->rules, rlist) {
317 e = container_of(r, struct audit_entry, rule);
318 audit_watch_log_rule_change(r, w, "remove rule");
321 list_del_rcu(&e->list);
322 call_rcu(&e->rcu, audit_free_rule_rcu);
324 audit_remove_watch(w);
326 mutex_unlock(&audit_filter_mutex);
329 /* Unregister inotify watches for parents on in_list.
330 * Generates an IN_IGNORED event. */
331 void audit_inotify_unregister(struct list_head *in_list)
333 struct audit_parent *p, *n;
335 list_for_each_entry_safe(p, n, in_list, ilist) {
337 inotify_rm_watch(audit_ih, &p->wdata);
338 /* the unpin matching the pin in audit_do_del_rule() */
339 unpin_inotify_watch(&p->wdata);
343 /* Get path information necessary for adding watches. */
344 static int audit_get_nd(char *path, struct nameidata **ndp, struct nameidata **ndw)
346 struct nameidata *ndparent, *ndwatch;
349 ndparent = kmalloc(sizeof(*ndparent), GFP_KERNEL);
350 if (unlikely(!ndparent))
353 ndwatch = kmalloc(sizeof(*ndwatch), GFP_KERNEL);
354 if (unlikely(!ndwatch)) {
359 err = path_lookup(path, LOOKUP_PARENT, ndparent);
366 err = path_lookup(path, 0, ndwatch);
378 /* Release resources used for watch path information. */
379 static void audit_put_nd(struct nameidata *ndp, struct nameidata *ndw)
382 path_put(&ndp->path);
386 path_put(&ndw->path);
391 /* Associate the given rule with an existing parent inotify_watch.
392 * Caller must hold audit_filter_mutex. */
393 static void audit_add_to_parent(struct audit_krule *krule,
394 struct audit_parent *parent)
396 struct audit_watch *w, *watch = krule->watch;
399 list_for_each_entry(w, &parent->watches, wlist) {
400 if (strcmp(watch->path, w->path))
405 /* put krule's and initial refs to temporary watch */
406 audit_put_watch(watch);
407 audit_put_watch(watch);
410 krule->watch = watch = w;
415 get_inotify_watch(&parent->wdata);
416 watch->parent = parent;
418 list_add(&watch->wlist, &parent->watches);
420 list_add(&krule->rlist, &watch->rules);
423 /* Find a matching watch entry, or add this one.
424 * Caller must hold audit_filter_mutex. */
425 int audit_add_watch(struct audit_krule *krule)
427 struct audit_watch *watch = krule->watch;
428 struct inotify_watch *i_watch;
429 struct audit_parent *parent;
430 struct nameidata *ndp = NULL, *ndw = NULL;
433 mutex_unlock(&audit_filter_mutex);
435 /* Avoid calling path_lookup under audit_filter_mutex. */
436 ret = audit_get_nd(watch->path, &ndp, &ndw);
438 /* caller expects mutex locked */
439 mutex_lock(&audit_filter_mutex);
443 /* update watch filter fields */
445 watch->dev = ndw->path.dentry->d_inode->i_sb->s_dev;
446 watch->ino = ndw->path.dentry->d_inode->i_ino;
449 /* The audit_filter_mutex must not be held during inotify calls because
450 * we hold it during inotify event callback processing. If an existing
451 * inotify watch is found, inotify_find_watch() grabs a reference before
454 if (inotify_find_watch(audit_ih, ndp->path.dentry->d_inode,
456 parent = audit_init_parent(ndp);
457 if (IS_ERR(parent)) {
458 /* caller expects mutex locked */
459 mutex_lock(&audit_filter_mutex);
460 ret = PTR_ERR(parent);
464 parent = container_of(i_watch, struct audit_parent, wdata);
466 mutex_lock(&audit_filter_mutex);
468 /* parent was moved before we took audit_filter_mutex */
469 if (parent->flags & AUDIT_PARENT_INVALID)
472 audit_add_to_parent(krule, parent);
474 /* match get in audit_init_parent or inotify_find_watch */
475 put_inotify_watch(&parent->wdata);
478 audit_put_nd(ndp, ndw); /* NULL args OK */
483 void audit_remove_watch_rule(struct audit_krule *krule, struct list_head *list)
485 struct audit_watch *watch = krule->watch;
486 struct audit_parent *parent = watch->parent;
488 list_del(&krule->rlist);
490 if (list_empty(&watch->rules)) {
491 audit_remove_watch(watch);
493 if (list_empty(&parent->watches)) {
494 /* Put parent on the inotify un-registration
495 * list. Grab a reference before releasing
496 * audit_filter_mutex, to be released in
497 * audit_inotify_unregister().
498 * If filesystem is going away, just leave
499 * the sucker alone, eviction will take
501 if (pin_inotify_watch(&parent->wdata))
502 list_add(&parent->ilist, list);
507 /* Update watch data in audit rules based on inotify events. */
508 static void audit_handle_ievent(struct inotify_watch *i_watch, u32 wd, u32 mask,
509 u32 cookie, const char *dname, struct inode *inode)
511 struct audit_parent *parent;
513 parent = container_of(i_watch, struct audit_parent, wdata);
515 if (mask & (IN_CREATE|IN_MOVED_TO) && inode)
516 audit_update_watch(parent, dname, inode->i_sb->s_dev,
518 else if (mask & (IN_DELETE|IN_MOVED_FROM))
519 audit_update_watch(parent, dname, (dev_t)-1, (unsigned long)-1, 1);
520 /* inotify automatically removes the watch and sends IN_IGNORED */
521 else if (mask & (IN_DELETE_SELF|IN_UNMOUNT))
522 audit_remove_parent_watches(parent);
523 /* inotify does not remove the watch, so remove it manually */
524 else if(mask & IN_MOVE_SELF) {
525 audit_remove_parent_watches(parent);
526 inotify_remove_watch_locked(audit_ih, i_watch);
527 } else if (mask & IN_IGNORED)
528 put_inotify_watch(i_watch);
531 static const struct inotify_operations audit_inotify_ops = {
532 .handle_event = audit_handle_ievent,
533 .destroy_watch = audit_free_parent,
536 static int __init audit_watch_init(void)
538 audit_ih = inotify_init(&audit_inotify_ops);
539 if (IS_ERR(audit_ih))
540 audit_panic("cannot initialize inotify handle");
543 subsys_initcall(audit_watch_init);