KVM: x86: Use jmp to invoke kvm_spurious_fault() from .fixup
[linux/fpc-iii.git] / kernel / audit_watch.c
blobf45a9a5d3e47a3a72a66b1482db0431f9be8ebcd
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>
27 #include <linux/fs.h>
28 #include <linux/fsnotify_backend.h>
29 #include <linux/namei.h>
30 #include <linux/netlink.h>
31 #include <linux/sched.h>
32 #include <linux/slab.h>
33 #include <linux/security.h>
34 #include "audit.h"
37 * Reference counting:
39 * audit_parent: lifetime is from audit_init_parent() to receipt of an FS_IGNORED
40 * event. Each audit_watch holds a reference to its associated parent.
42 * audit_watch: if added to lists, lifetime is from audit_init_watch() to
43 * audit_remove_watch(). Additionally, an audit_watch may exist
44 * temporarily to assist in searching existing filter data. Each
45 * audit_krule holds a reference to its associated watch.
48 struct audit_watch {
49 atomic_t count; /* reference count */
50 dev_t dev; /* associated superblock device */
51 char *path; /* insertion path */
52 unsigned long ino; /* associated inode number */
53 struct audit_parent *parent; /* associated parent */
54 struct list_head wlist; /* entry in parent->watches list */
55 struct list_head rules; /* anchor for krule->rlist */
58 struct audit_parent {
59 struct list_head watches; /* anchor for audit_watch->wlist */
60 struct fsnotify_mark mark; /* fsnotify mark on the inode */
63 /* fsnotify handle. */
64 static struct fsnotify_group *audit_watch_group;
66 /* fsnotify events we care about. */
67 #define AUDIT_FS_WATCH (FS_MOVE | FS_CREATE | FS_DELETE | FS_DELETE_SELF |\
68 FS_MOVE_SELF | FS_EVENT_ON_CHILD)
70 static void audit_free_parent(struct audit_parent *parent)
72 WARN_ON(!list_empty(&parent->watches));
73 kfree(parent);
76 static void audit_watch_free_mark(struct fsnotify_mark *entry)
78 struct audit_parent *parent;
80 parent = container_of(entry, struct audit_parent, mark);
81 audit_free_parent(parent);
84 static void audit_get_parent(struct audit_parent *parent)
86 if (likely(parent))
87 fsnotify_get_mark(&parent->mark);
90 static void audit_put_parent(struct audit_parent *parent)
92 if (likely(parent))
93 fsnotify_put_mark(&parent->mark);
97 * Find and return the audit_parent on the given inode. If found a reference
98 * is taken on this parent.
100 static inline struct audit_parent *audit_find_parent(struct inode *inode)
102 struct audit_parent *parent = NULL;
103 struct fsnotify_mark *entry;
105 entry = fsnotify_find_inode_mark(audit_watch_group, inode);
106 if (entry)
107 parent = container_of(entry, struct audit_parent, mark);
109 return parent;
112 void audit_get_watch(struct audit_watch *watch)
114 atomic_inc(&watch->count);
117 void audit_put_watch(struct audit_watch *watch)
119 if (atomic_dec_and_test(&watch->count)) {
120 WARN_ON(watch->parent);
121 WARN_ON(!list_empty(&watch->rules));
122 kfree(watch->path);
123 kfree(watch);
127 static void audit_remove_watch(struct audit_watch *watch)
129 list_del(&watch->wlist);
130 audit_put_parent(watch->parent);
131 watch->parent = NULL;
132 audit_put_watch(watch); /* match initial get */
135 char *audit_watch_path(struct audit_watch *watch)
137 return watch->path;
140 int audit_watch_compare(struct audit_watch *watch, unsigned long ino, dev_t dev)
142 return (watch->ino != AUDIT_INO_UNSET) &&
143 (watch->ino == ino) &&
144 (watch->dev == dev);
147 /* Initialize a parent watch entry. */
148 static struct audit_parent *audit_init_parent(struct path *path)
150 struct inode *inode = d_backing_inode(path->dentry);
151 struct audit_parent *parent;
152 int ret;
154 parent = kzalloc(sizeof(*parent), GFP_KERNEL);
155 if (unlikely(!parent))
156 return ERR_PTR(-ENOMEM);
158 INIT_LIST_HEAD(&parent->watches);
160 fsnotify_init_mark(&parent->mark, audit_watch_free_mark);
161 parent->mark.mask = AUDIT_FS_WATCH;
162 ret = fsnotify_add_mark(&parent->mark, audit_watch_group, inode, NULL, 0);
163 if (ret < 0) {
164 audit_free_parent(parent);
165 return ERR_PTR(ret);
168 return parent;
171 /* Initialize a watch entry. */
172 static struct audit_watch *audit_init_watch(char *path)
174 struct audit_watch *watch;
176 watch = kzalloc(sizeof(*watch), GFP_KERNEL);
177 if (unlikely(!watch))
178 return ERR_PTR(-ENOMEM);
180 INIT_LIST_HEAD(&watch->rules);
181 atomic_set(&watch->count, 1);
182 watch->path = path;
183 watch->dev = AUDIT_DEV_UNSET;
184 watch->ino = AUDIT_INO_UNSET;
186 return watch;
189 /* Translate a watch string to kernel respresentation. */
190 int audit_to_watch(struct audit_krule *krule, char *path, int len, u32 op)
192 struct audit_watch *watch;
194 if (!audit_watch_group)
195 return -EOPNOTSUPP;
197 if (path[0] != '/' || path[len-1] == '/' ||
198 krule->listnr != AUDIT_FILTER_EXIT ||
199 op != Audit_equal ||
200 krule->inode_f || krule->watch || krule->tree)
201 return -EINVAL;
203 watch = audit_init_watch(path);
204 if (IS_ERR(watch))
205 return PTR_ERR(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 if (unlikely(!ab))
244 return;
245 audit_log_format(ab, "auid=%u ses=%u op=",
246 from_kuid(&init_user_ns, audit_get_loginuid(current)),
247 audit_get_sessionid(current));
248 audit_log_string(ab, op);
249 audit_log_format(ab, " path=");
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);
253 audit_log_end(ab);
257 /* Update inode info in audit rules based on filesystem event. */
258 static void audit_update_watch(struct audit_parent *parent,
259 const char *dname, dev_t dev,
260 unsigned long ino, unsigned invalidating)
262 struct audit_watch *owatch, *nwatch, *nextw;
263 struct audit_krule *r, *nextr;
264 struct audit_entry *oentry, *nentry;
266 mutex_lock(&audit_filter_mutex);
267 /* Run all of the watches on this parent looking for the one that
268 * matches the given dname */
269 list_for_each_entry_safe(owatch, nextw, &parent->watches, wlist) {
270 if (audit_compare_dname_path(dname, owatch->path,
271 AUDIT_NAME_FULL))
272 continue;
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");
285 return;
287 nwatch->dev = dev;
288 nwatch->ino = ino;
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");
300 } else {
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
306 * new watch.
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,
314 &nentry->rule.list);
316 if (oentry->rule.exe)
317 audit_remove_mark(oentry->rule.exe);
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);
328 return;
330 add_watch_to_parent:
331 list_add(&nwatch->wlist, &parent->watches);
332 mutex_unlock(&audit_filter_mutex);
333 return;
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");
348 if (e->rule.exe)
349 audit_remove_mark(e->rule.exe);
350 list_del(&r->rlist);
351 list_del(&r->list);
352 list_del_rcu(&e->list);
353 call_rcu(&e->rcu, audit_free_rule_rcu);
355 audit_remove_watch(w);
357 mutex_unlock(&audit_filter_mutex);
359 fsnotify_destroy_mark(&parent->mark, audit_watch_group);
362 /* Get path information necessary for adding watches. */
363 static int audit_get_nd(struct audit_watch *watch, struct path *parent)
365 struct dentry *d = kern_path_locked(watch->path, parent);
366 if (IS_ERR(d))
367 return PTR_ERR(d);
368 mutex_unlock(&d_backing_inode(parent->dentry)->i_mutex);
369 if (d_is_positive(d)) {
370 /* update watch filter fields */
371 watch->dev = d_backing_inode(d)->i_sb->s_dev;
372 watch->ino = d_backing_inode(d)->i_ino;
374 dput(d);
375 return 0;
378 /* Associate the given rule with an existing parent.
379 * Caller must hold audit_filter_mutex. */
380 static void audit_add_to_parent(struct audit_krule *krule,
381 struct audit_parent *parent)
383 struct audit_watch *w, *watch = krule->watch;
384 int watch_found = 0;
386 BUG_ON(!mutex_is_locked(&audit_filter_mutex));
388 list_for_each_entry(w, &parent->watches, wlist) {
389 if (strcmp(watch->path, w->path))
390 continue;
392 watch_found = 1;
394 /* put krule's ref to temporary watch */
395 audit_put_watch(watch);
397 audit_get_watch(w);
398 krule->watch = watch = w;
400 audit_put_parent(parent);
401 break;
404 if (!watch_found) {
405 watch->parent = parent;
407 audit_get_watch(watch);
408 list_add(&watch->wlist, &parent->watches);
410 list_add(&krule->rlist, &watch->rules);
413 /* Find a matching watch entry, or add this one.
414 * Caller must hold audit_filter_mutex. */
415 int audit_add_watch(struct audit_krule *krule, struct list_head **list)
417 struct audit_watch *watch = krule->watch;
418 struct audit_parent *parent;
419 struct path parent_path;
420 int h, ret = 0;
423 * When we will be calling audit_add_to_parent, krule->watch might have
424 * been updated and watch might have been freed.
425 * So we need to keep a reference of watch.
427 audit_get_watch(watch);
429 mutex_unlock(&audit_filter_mutex);
431 /* Avoid calling path_lookup under audit_filter_mutex. */
432 ret = audit_get_nd(watch, &parent_path);
434 /* caller expects mutex locked */
435 mutex_lock(&audit_filter_mutex);
437 if (ret) {
438 audit_put_watch(watch);
439 return ret;
442 /* either find an old parent or attach a new one */
443 parent = audit_find_parent(d_backing_inode(parent_path.dentry));
444 if (!parent) {
445 parent = audit_init_parent(&parent_path);
446 if (IS_ERR(parent)) {
447 ret = PTR_ERR(parent);
448 goto error;
452 audit_add_to_parent(krule, parent);
454 h = audit_hash_ino((u32)watch->ino);
455 *list = &audit_inode_hash[h];
456 error:
457 path_put(&parent_path);
458 audit_put_watch(watch);
459 return ret;
462 void audit_remove_watch_rule(struct audit_krule *krule)
464 struct audit_watch *watch = krule->watch;
465 struct audit_parent *parent = watch->parent;
467 list_del(&krule->rlist);
469 if (list_empty(&watch->rules)) {
471 * audit_remove_watch() drops our reference to 'parent' which
472 * can get freed. Grab our own reference to be safe.
474 audit_get_parent(parent);
475 audit_remove_watch(watch);
476 if (list_empty(&parent->watches))
477 fsnotify_destroy_mark(&parent->mark, audit_watch_group);
478 audit_put_parent(parent);
482 /* Update watch data in audit rules based on fsnotify events. */
483 static int audit_watch_handle_event(struct fsnotify_group *group,
484 struct inode *to_tell,
485 struct fsnotify_mark *inode_mark,
486 struct fsnotify_mark *vfsmount_mark,
487 u32 mask, void *data, int data_type,
488 const unsigned char *dname, u32 cookie)
490 struct inode *inode;
491 struct audit_parent *parent;
493 parent = container_of(inode_mark, struct audit_parent, mark);
495 BUG_ON(group != audit_watch_group);
497 switch (data_type) {
498 case (FSNOTIFY_EVENT_PATH):
499 inode = d_backing_inode(((struct path *)data)->dentry);
500 break;
501 case (FSNOTIFY_EVENT_INODE):
502 inode = (struct inode *)data;
503 break;
504 default:
505 BUG();
506 inode = NULL;
507 break;
510 if (mask & (FS_CREATE|FS_MOVED_TO) && inode)
511 audit_update_watch(parent, dname, inode->i_sb->s_dev, inode->i_ino, 0);
512 else if (mask & (FS_DELETE|FS_MOVED_FROM))
513 audit_update_watch(parent, dname, AUDIT_DEV_UNSET, AUDIT_INO_UNSET, 1);
514 else if (mask & (FS_DELETE_SELF|FS_UNMOUNT|FS_MOVE_SELF))
515 audit_remove_parent_watches(parent);
517 return 0;
520 static const struct fsnotify_ops audit_watch_fsnotify_ops = {
521 .handle_event = audit_watch_handle_event,
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");
531 return 0;
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;
538 char *pathname;
540 pathname = kstrdup(audit_mark_path(old->exe), GFP_KERNEL);
541 if (!pathname)
542 return -ENOMEM;
544 audit_mark = audit_alloc_mark(new, pathname, strlen(pathname));
545 if (IS_ERR(audit_mark)) {
546 kfree(pathname);
547 return PTR_ERR(audit_mark);
549 new->exe = audit_mark;
551 return 0;
554 int audit_exe_compare(struct task_struct *tsk, struct audit_fsnotify_mark *mark)
556 struct file *exe_file;
557 unsigned long ino;
558 dev_t dev;
560 exe_file = get_task_exe_file(tsk);
561 if (!exe_file)
562 return 0;
563 ino = exe_file->f_inode->i_ino;
564 dev = exe_file->f_inode->i_sb->s_dev;
565 fput(exe_file);
566 return audit_mark_compare(mark, ino, dev);