x86/paravirt: PTE updates in k(un)map_atomic need to be synchronous, regardless of...
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / kernel / audit_watch.c
blobe683869365d9bdaf60abcb44e37da05506ab5672
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>
26 #include <linux/fs.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>
33 #include "audit.h"
36 * Reference counting:
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.
47 struct audit_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 */
57 struct audit_parent {
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));
72 kfree(parent);
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)
85 if (likely(parent))
86 fsnotify_get_mark(&parent->mark);
89 static void audit_put_parent(struct audit_parent *parent)
91 if (likely(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);
105 if (entry)
106 parent = container_of(entry, struct audit_parent, mark);
108 return parent;
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));
121 kfree(watch->path);
122 kfree(watch);
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)
136 return watch->path;
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) &&
143 (watch->dev == dev);
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;
151 int ret;
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);
162 if (ret < 0) {
163 audit_free_parent(parent);
164 return ERR_PTR(ret);
167 return 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);
181 watch->path = path;
182 watch->dev = (dev_t)-1;
183 watch->ino = (unsigned long)-1;
185 return watch;
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)
194 return -EOPNOTSUPP;
196 if (path[0] != '/' || path[len-1] == '/' ||
197 krule->listnr != AUDIT_FILTER_EXIT ||
198 op != Audit_equal ||
199 krule->inode_f || krule->watch || krule->tree)
200 return -EINVAL;
202 watch = audit_init_watch(path);
203 if (IS_ERR(watch))
204 return PTR_ERR(watch);
206 audit_get_watch(watch);
207 krule->watch = watch;
209 return 0;
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)
216 char *path;
217 struct audit_watch *new;
219 path = kstrdup(old->path, GFP_KERNEL);
220 if (unlikely(!path))
221 return ERR_PTR(-ENOMEM);
223 new = audit_init_watch(path);
224 if (IS_ERR(new)) {
225 kfree(path);
226 goto out;
229 new->dev = old->dev;
230 new->ino = old->ino;
231 audit_get_parent(old->parent);
232 new->parent = old->parent;
234 out:
235 return new;
238 static void audit_watch_log_rule_change(struct audit_krule *r, struct audit_watch *w, char *op)
240 if (audit_enabled) {
241 struct audit_buffer *ab;
242 ab = audit_log_start(NULL, GFP_NOFS, AUDIT_CONFIG_CHANGE);
243 audit_log_format(ab, "auid=%u ses=%u op=",
244 audit_get_loginuid(current),
245 audit_get_sessionid(current));
246 audit_log_string(ab, op);
247 audit_log_format(ab, " path=");
248 audit_log_untrustedstring(ab, w->path);
249 audit_log_key(ab, r->filterkey);
250 audit_log_format(ab, " list=%d res=1", r->listnr);
251 audit_log_end(ab);
255 /* Update inode info in audit rules based on filesystem event. */
256 static void audit_update_watch(struct audit_parent *parent,
257 const char *dname, dev_t dev,
258 unsigned long ino, unsigned invalidating)
260 struct audit_watch *owatch, *nwatch, *nextw;
261 struct audit_krule *r, *nextr;
262 struct audit_entry *oentry, *nentry;
264 mutex_lock(&audit_filter_mutex);
265 /* Run all of the watches on this parent looking for the one that
266 * matches the given dname */
267 list_for_each_entry_safe(owatch, nextw, &parent->watches, wlist) {
268 if (audit_compare_dname_path(dname, owatch->path, NULL))
269 continue;
271 /* If the update involves invalidating rules, do the inode-based
272 * filtering now, so we don't omit records. */
273 if (invalidating && !audit_dummy_context())
274 audit_filter_inodes(current, current->audit_context);
276 /* updating ino will likely change which audit_hash_list we
277 * are on so we need a new watch for the new list */
278 nwatch = audit_dupe_watch(owatch);
279 if (IS_ERR(nwatch)) {
280 mutex_unlock(&audit_filter_mutex);
281 audit_panic("error updating watch, skipping");
282 return;
284 nwatch->dev = dev;
285 nwatch->ino = ino;
287 list_for_each_entry_safe(r, nextr, &owatch->rules, rlist) {
289 oentry = container_of(r, struct audit_entry, rule);
290 list_del(&oentry->rule.rlist);
291 list_del_rcu(&oentry->list);
293 nentry = audit_dupe_rule(&oentry->rule);
294 if (IS_ERR(nentry)) {
295 list_del(&oentry->rule.list);
296 audit_panic("error updating watch, removing");
297 } else {
298 int h = audit_hash_ino((u32)ino);
301 * nentry->rule.watch == oentry->rule.watch so
302 * we must drop that reference and set it to our
303 * new watch.
305 audit_put_watch(nentry->rule.watch);
306 audit_get_watch(nwatch);
307 nentry->rule.watch = nwatch;
308 list_add(&nentry->rule.rlist, &nwatch->rules);
309 list_add_rcu(&nentry->list, &audit_inode_hash[h]);
310 list_replace(&oentry->rule.list,
311 &nentry->rule.list);
314 audit_watch_log_rule_change(r, owatch, "updated rules");
316 call_rcu(&oentry->rcu, audit_free_rule_rcu);
319 audit_remove_watch(owatch);
320 goto add_watch_to_parent; /* event applies to a single watch */
322 mutex_unlock(&audit_filter_mutex);
323 return;
325 add_watch_to_parent:
326 list_add(&nwatch->wlist, &parent->watches);
327 mutex_unlock(&audit_filter_mutex);
328 return;
331 /* Remove all watches & rules associated with a parent that is going away. */
332 static void audit_remove_parent_watches(struct audit_parent *parent)
334 struct audit_watch *w, *nextw;
335 struct audit_krule *r, *nextr;
336 struct audit_entry *e;
338 mutex_lock(&audit_filter_mutex);
339 list_for_each_entry_safe(w, nextw, &parent->watches, wlist) {
340 list_for_each_entry_safe(r, nextr, &w->rules, rlist) {
341 e = container_of(r, struct audit_entry, rule);
342 audit_watch_log_rule_change(r, w, "remove rule");
343 list_del(&r->rlist);
344 list_del(&r->list);
345 list_del_rcu(&e->list);
346 call_rcu(&e->rcu, audit_free_rule_rcu);
348 audit_remove_watch(w);
350 mutex_unlock(&audit_filter_mutex);
352 fsnotify_destroy_mark(&parent->mark);
355 /* Get path information necessary for adding watches. */
356 static int audit_get_nd(struct audit_watch *watch, struct path *parent)
358 struct nameidata nd;
359 struct dentry *d;
360 int err;
362 err = kern_path_parent(watch->path, &nd);
363 if (err)
364 return err;
366 if (nd.last_type != LAST_NORM) {
367 path_put(&nd.path);
368 return -EINVAL;
371 mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
372 d = lookup_one_len(nd.last.name, nd.path.dentry, nd.last.len);
373 if (IS_ERR(d)) {
374 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
375 path_put(&nd.path);
376 return PTR_ERR(d);
378 if (d->d_inode) {
379 /* update watch filter fields */
380 watch->dev = d->d_inode->i_sb->s_dev;
381 watch->ino = d->d_inode->i_ino;
383 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
385 *parent = nd.path;
386 dput(d);
387 return 0;
390 /* Associate the given rule with an existing parent.
391 * Caller must hold audit_filter_mutex. */
392 static void audit_add_to_parent(struct audit_krule *krule,
393 struct audit_parent *parent)
395 struct audit_watch *w, *watch = krule->watch;
396 int watch_found = 0;
398 BUG_ON(!mutex_is_locked(&audit_filter_mutex));
400 list_for_each_entry(w, &parent->watches, wlist) {
401 if (strcmp(watch->path, w->path))
402 continue;
404 watch_found = 1;
406 /* put krule's and initial refs to temporary watch */
407 audit_put_watch(watch);
408 audit_put_watch(watch);
410 audit_get_watch(w);
411 krule->watch = watch = w;
412 break;
415 if (!watch_found) {
416 audit_get_parent(parent);
417 watch->parent = parent;
419 list_add(&watch->wlist, &parent->watches);
421 list_add(&krule->rlist, &watch->rules);
424 /* Find a matching watch entry, or add this one.
425 * Caller must hold audit_filter_mutex. */
426 int audit_add_watch(struct audit_krule *krule, struct list_head **list)
428 struct audit_watch *watch = krule->watch;
429 struct audit_parent *parent;
430 struct path parent_path;
431 int h, ret = 0;
433 mutex_unlock(&audit_filter_mutex);
435 /* Avoid calling path_lookup under audit_filter_mutex. */
436 ret = audit_get_nd(watch, &parent_path);
438 /* caller expects mutex locked */
439 mutex_lock(&audit_filter_mutex);
441 if (ret)
442 return ret;
444 /* either find an old parent or attach a new one */
445 parent = audit_find_parent(parent_path.dentry->d_inode);
446 if (!parent) {
447 parent = audit_init_parent(&parent_path);
448 if (IS_ERR(parent)) {
449 ret = PTR_ERR(parent);
450 goto error;
454 audit_add_to_parent(krule, parent);
456 /* match get in audit_find_parent or audit_init_parent */
457 audit_put_parent(parent);
459 h = audit_hash_ino((u32)watch->ino);
460 *list = &audit_inode_hash[h];
461 error:
462 path_put(&parent_path);
463 return ret;
466 void audit_remove_watch_rule(struct audit_krule *krule)
468 struct audit_watch *watch = krule->watch;
469 struct audit_parent *parent = watch->parent;
471 list_del(&krule->rlist);
473 if (list_empty(&watch->rules)) {
474 audit_remove_watch(watch);
476 if (list_empty(&parent->watches)) {
477 audit_get_parent(parent);
478 fsnotify_destroy_mark(&parent->mark);
479 audit_put_parent(parent);
484 static bool audit_watch_should_send_event(struct fsnotify_group *group, struct inode *inode,
485 struct fsnotify_mark *inode_mark,
486 struct fsnotify_mark *vfsmount_mark,
487 __u32 mask, void *data, int data_type)
489 return true;
492 /* Update watch data in audit rules based on fsnotify events. */
493 static int audit_watch_handle_event(struct fsnotify_group *group,
494 struct fsnotify_mark *inode_mark,
495 struct fsnotify_mark *vfsmount_mark,
496 struct fsnotify_event *event)
498 struct inode *inode;
499 __u32 mask = event->mask;
500 const char *dname = event->file_name;
501 struct audit_parent *parent;
503 parent = container_of(inode_mark, struct audit_parent, mark);
505 BUG_ON(group != audit_watch_group);
507 switch (event->data_type) {
508 case (FSNOTIFY_EVENT_PATH):
509 inode = event->path.dentry->d_inode;
510 break;
511 case (FSNOTIFY_EVENT_INODE):
512 inode = event->inode;
513 break;
514 default:
515 BUG();
516 inode = NULL;
517 break;
520 if (mask & (FS_CREATE|FS_MOVED_TO) && inode)
521 audit_update_watch(parent, dname, inode->i_sb->s_dev, inode->i_ino, 0);
522 else if (mask & (FS_DELETE|FS_MOVED_FROM))
523 audit_update_watch(parent, dname, (dev_t)-1, (unsigned long)-1, 1);
524 else if (mask & (FS_DELETE_SELF|FS_UNMOUNT|FS_MOVE_SELF))
525 audit_remove_parent_watches(parent);
527 return 0;
530 static const struct fsnotify_ops audit_watch_fsnotify_ops = {
531 .should_send_event = audit_watch_should_send_event,
532 .handle_event = audit_watch_handle_event,
533 .free_group_priv = NULL,
534 .freeing_mark = NULL,
535 .free_event_priv = NULL,
538 static int __init audit_watch_init(void)
540 audit_watch_group = fsnotify_alloc_group(&audit_watch_fsnotify_ops);
541 if (IS_ERR(audit_watch_group)) {
542 audit_watch_group = NULL;
543 audit_panic("cannot create audit fsnotify group");
545 return 0;
547 device_initcall(audit_watch_init);