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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* audit_watch.c -- watching inodes
3 *
4 * Copyright 2003-2009 Red Hat, Inc.
5 * Copyright 2005 Hewlett-Packard Development Company, L.P.
6 * Copyright 2005 IBM Corporation
7 */
8
9#include <linux/file.h>
10#include <linux/kernel.h>
11#include <linux/audit.h>
12#include <linux/kthread.h>
13#include <linux/mutex.h>
14#include <linux/fs.h>
15#include <linux/fsnotify_backend.h>
16#include <linux/namei.h>
17#include <linux/netlink.h>
18#include <linux/refcount.h>
19#include <linux/sched.h>
20#include <linux/slab.h>
21#include <linux/security.h>
22#include "audit.h"
23
24/*
25 * Reference counting:
26 *
27 * audit_parent: lifetime is from audit_init_parent() to receipt of an FS_IGNORED
28 * event. Each audit_watch holds a reference to its associated parent.
29 *
30 * audit_watch: if added to lists, lifetime is from audit_init_watch() to
31 * audit_remove_watch(). Additionally, an audit_watch may exist
32 * temporarily to assist in searching existing filter data. Each
33 * audit_krule holds a reference to its associated watch.
34 */
35
36struct audit_watch {
37 refcount_t count; /* reference count */
38 dev_t dev; /* associated superblock device */
39 char *path; /* insertion path */
40 unsigned long ino; /* associated inode number */
41 struct audit_parent *parent; /* associated parent */
42 struct list_head wlist; /* entry in parent->watches list */
43 struct list_head rules; /* anchor for krule->rlist */
44};
45
46struct audit_parent {
47 struct list_head watches; /* anchor for audit_watch->wlist */
48 struct fsnotify_mark mark; /* fsnotify mark on the inode */
49};
50
51/* fsnotify handle. */
52static struct fsnotify_group *audit_watch_group;
53
54/* fsnotify events we care about. */
55#define AUDIT_FS_WATCH (FS_MOVE | FS_CREATE | FS_DELETE | FS_DELETE_SELF |\
56 FS_MOVE_SELF | FS_EVENT_ON_CHILD | FS_UNMOUNT)
57
58static void audit_free_parent(struct audit_parent *parent)
59{
60 WARN_ON(!list_empty(&parent->watches));
61 kfree(parent);
62}
63
64static void audit_watch_free_mark(struct fsnotify_mark *entry)
65{
66 struct audit_parent *parent;
67
68 parent = container_of(entry, struct audit_parent, mark);
69 audit_free_parent(parent);
70}
71
72static void audit_get_parent(struct audit_parent *parent)
73{
74 if (likely(parent))
75 fsnotify_get_mark(&parent->mark);
76}
77
78static void audit_put_parent(struct audit_parent *parent)
79{
80 if (likely(parent))
81 fsnotify_put_mark(&parent->mark);
82}
83
84/*
85 * Find and return the audit_parent on the given inode. If found a reference
86 * is taken on this parent.
87 */
88static inline struct audit_parent *audit_find_parent(struct inode *inode)
89{
90 struct audit_parent *parent = NULL;
91 struct fsnotify_mark *entry;
92
93 entry = fsnotify_find_mark(&inode->i_fsnotify_marks, audit_watch_group);
94 if (entry)
95 parent = container_of(entry, struct audit_parent, mark);
96
97 return parent;
98}
99
100void audit_get_watch(struct audit_watch *watch)
101{
102 refcount_inc(&watch->count);
103}
104
105void audit_put_watch(struct audit_watch *watch)
106{
107 if (refcount_dec_and_test(&watch->count)) {
108 WARN_ON(watch->parent);
109 WARN_ON(!list_empty(&watch->rules));
110 kfree(watch->path);
111 kfree(watch);
112 }
113}
114
115static void audit_remove_watch(struct audit_watch *watch)
116{
117 list_del(&watch->wlist);
118 audit_put_parent(watch->parent);
119 watch->parent = NULL;
120 audit_put_watch(watch); /* match initial get */
121}
122
123char *audit_watch_path(struct audit_watch *watch)
124{
125 return watch->path;
126}
127
128int audit_watch_compare(struct audit_watch *watch, unsigned long ino, dev_t dev)
129{
130 return (watch->ino != AUDIT_INO_UNSET) &&
131 (watch->ino == ino) &&
132 (watch->dev == dev);
133}
134
135/* Initialize a parent watch entry. */
136static struct audit_parent *audit_init_parent(struct path *path)
137{
138 struct inode *inode = d_backing_inode(path->dentry);
139 struct audit_parent *parent;
140 int ret;
141
142 parent = kzalloc(sizeof(*parent), GFP_KERNEL);
143 if (unlikely(!parent))
144 return ERR_PTR(-ENOMEM);
145
146 INIT_LIST_HEAD(&parent->watches);
147
148 fsnotify_init_mark(&parent->mark, audit_watch_group);
149 parent->mark.mask = AUDIT_FS_WATCH;
150 ret = fsnotify_add_inode_mark(&parent->mark, inode, 0);
151 if (ret < 0) {
152 audit_free_parent(parent);
153 return ERR_PTR(ret);
154 }
155
156 return parent;
157}
158
159/* Initialize a watch entry. */
160static struct audit_watch *audit_init_watch(char *path)
161{
162 struct audit_watch *watch;
163
164 watch = kzalloc(sizeof(*watch), GFP_KERNEL);
165 if (unlikely(!watch))
166 return ERR_PTR(-ENOMEM);
167
168 INIT_LIST_HEAD(&watch->rules);
169 refcount_set(&watch->count, 1);
170 watch->path = path;
171 watch->dev = AUDIT_DEV_UNSET;
172 watch->ino = AUDIT_INO_UNSET;
173
174 return watch;
175}
176
177/* Translate a watch string to kernel representation. */
178int audit_to_watch(struct audit_krule *krule, char *path, int len, u32 op)
179{
180 struct audit_watch *watch;
181
182 if (!audit_watch_group)
183 return -EOPNOTSUPP;
184
185 if (path[0] != '/' || path[len-1] == '/' ||
186 krule->listnr != AUDIT_FILTER_EXIT ||
187 op != Audit_equal ||
188 krule->inode_f || krule->watch || krule->tree)
189 return -EINVAL;
190
191 watch = audit_init_watch(path);
192 if (IS_ERR(watch))
193 return PTR_ERR(watch);
194
195 krule->watch = watch;
196
197 return 0;
198}
199
200/* Duplicate the given audit watch. The new watch's rules list is initialized
201 * to an empty list and wlist is undefined. */
202static struct audit_watch *audit_dupe_watch(struct audit_watch *old)
203{
204 char *path;
205 struct audit_watch *new;
206
207 path = kstrdup(old->path, GFP_KERNEL);
208 if (unlikely(!path))
209 return ERR_PTR(-ENOMEM);
210
211 new = audit_init_watch(path);
212 if (IS_ERR(new)) {
213 kfree(path);
214 goto out;
215 }
216
217 new->dev = old->dev;
218 new->ino = old->ino;
219 audit_get_parent(old->parent);
220 new->parent = old->parent;
221
222out:
223 return new;
224}
225
226static void audit_watch_log_rule_change(struct audit_krule *r, struct audit_watch *w, char *op)
227{
228 struct audit_buffer *ab;
229
230 if (!audit_enabled)
231 return;
232 ab = audit_log_start(audit_context(), GFP_NOFS, AUDIT_CONFIG_CHANGE);
233 if (!ab)
234 return;
235 audit_log_session_info(ab);
236 audit_log_format(ab, "op=%s path=", op);
237 audit_log_untrustedstring(ab, w->path);
238 audit_log_key(ab, r->filterkey);
239 audit_log_format(ab, " list=%d res=1", r->listnr);
240 audit_log_end(ab);
241}
242
243/* Update inode info in audit rules based on filesystem event. */
244static void audit_update_watch(struct audit_parent *parent,
245 const struct qstr *dname, dev_t dev,
246 unsigned long ino, unsigned invalidating)
247{
248 struct audit_watch *owatch, *nwatch, *nextw;
249 struct audit_krule *r, *nextr;
250 struct audit_entry *oentry, *nentry;
251
252 mutex_lock(&audit_filter_mutex);
253 /* Run all of the watches on this parent looking for the one that
254 * matches the given dname */
255 list_for_each_entry_safe(owatch, nextw, &parent->watches, wlist) {
256 if (audit_compare_dname_path(dname, owatch->path,
257 AUDIT_NAME_FULL))
258 continue;
259
260 /* If the update involves invalidating rules, do the inode-based
261 * filtering now, so we don't omit records. */
262 if (invalidating && !audit_dummy_context())
263 audit_filter_inodes(current, audit_context());
264
265 /* updating ino will likely change which audit_hash_list we
266 * are on so we need a new watch for the new list */
267 nwatch = audit_dupe_watch(owatch);
268 if (IS_ERR(nwatch)) {
269 mutex_unlock(&audit_filter_mutex);
270 audit_panic("error updating watch, skipping");
271 return;
272 }
273 nwatch->dev = dev;
274 nwatch->ino = ino;
275
276 list_for_each_entry_safe(r, nextr, &owatch->rules, rlist) {
277
278 oentry = container_of(r, struct audit_entry, rule);
279 list_del(&oentry->rule.rlist);
280 list_del_rcu(&oentry->list);
281
282 nentry = audit_dupe_rule(&oentry->rule);
283 if (IS_ERR(nentry)) {
284 list_del(&oentry->rule.list);
285 audit_panic("error updating watch, removing");
286 } else {
287 int h = audit_hash_ino((u32)ino);
288
289 /*
290 * nentry->rule.watch == oentry->rule.watch so
291 * we must drop that reference and set it to our
292 * new watch.
293 */
294 audit_put_watch(nentry->rule.watch);
295 audit_get_watch(nwatch);
296 nentry->rule.watch = nwatch;
297 list_add(&nentry->rule.rlist, &nwatch->rules);
298 list_add_rcu(&nentry->list, &audit_inode_hash[h]);
299 list_replace(&oentry->rule.list,
300 &nentry->rule.list);
301 }
302 if (oentry->rule.exe)
303 audit_remove_mark(oentry->rule.exe);
304
305 audit_watch_log_rule_change(r, owatch, "updated_rules");
306
307 call_rcu(&oentry->rcu, audit_free_rule_rcu);
308 }
309
310 audit_remove_watch(owatch);
311 goto add_watch_to_parent; /* event applies to a single watch */
312 }
313 mutex_unlock(&audit_filter_mutex);
314 return;
315
316add_watch_to_parent:
317 list_add(&nwatch->wlist, &parent->watches);
318 mutex_unlock(&audit_filter_mutex);
319 return;
320}
321
322/* Remove all watches & rules associated with a parent that is going away. */
323static void audit_remove_parent_watches(struct audit_parent *parent)
324{
325 struct audit_watch *w, *nextw;
326 struct audit_krule *r, *nextr;
327 struct audit_entry *e;
328
329 mutex_lock(&audit_filter_mutex);
330 list_for_each_entry_safe(w, nextw, &parent->watches, wlist) {
331 list_for_each_entry_safe(r, nextr, &w->rules, rlist) {
332 e = container_of(r, struct audit_entry, rule);
333 audit_watch_log_rule_change(r, w, "remove_rule");
334 if (e->rule.exe)
335 audit_remove_mark(e->rule.exe);
336 list_del(&r->rlist);
337 list_del(&r->list);
338 list_del_rcu(&e->list);
339 call_rcu(&e->rcu, audit_free_rule_rcu);
340 }
341 audit_remove_watch(w);
342 }
343 mutex_unlock(&audit_filter_mutex);
344
345 fsnotify_destroy_mark(&parent->mark, audit_watch_group);
346}
347
348/* Get path information necessary for adding watches. */
349static int audit_get_nd(struct audit_watch *watch, struct path *parent)
350{
351 struct dentry *d = kern_path_locked(watch->path, parent);
352 if (IS_ERR(d))
353 return PTR_ERR(d);
354 if (d_is_positive(d)) {
355 /* update watch filter fields */
356 watch->dev = d->d_sb->s_dev;
357 watch->ino = d_backing_inode(d)->i_ino;
358 }
359 inode_unlock(d_backing_inode(parent->dentry));
360 dput(d);
361 return 0;
362}
363
364/* Associate the given rule with an existing parent.
365 * Caller must hold audit_filter_mutex. */
366static void audit_add_to_parent(struct audit_krule *krule,
367 struct audit_parent *parent)
368{
369 struct audit_watch *w, *watch = krule->watch;
370 int watch_found = 0;
371
372 BUG_ON(!mutex_is_locked(&audit_filter_mutex));
373
374 list_for_each_entry(w, &parent->watches, wlist) {
375 if (strcmp(watch->path, w->path))
376 continue;
377
378 watch_found = 1;
379
380 /* put krule's ref to temporary watch */
381 audit_put_watch(watch);
382
383 audit_get_watch(w);
384 krule->watch = watch = w;
385
386 audit_put_parent(parent);
387 break;
388 }
389
390 if (!watch_found) {
391 watch->parent = parent;
392
393 audit_get_watch(watch);
394 list_add(&watch->wlist, &parent->watches);
395 }
396 list_add(&krule->rlist, &watch->rules);
397}
398
399/* Find a matching watch entry, or add this one.
400 * Caller must hold audit_filter_mutex. */
401int audit_add_watch(struct audit_krule *krule, struct list_head **list)
402{
403 struct audit_watch *watch = krule->watch;
404 struct audit_parent *parent;
405 struct path parent_path;
406 int h, ret = 0;
407
408 /*
409 * When we will be calling audit_add_to_parent, krule->watch might have
410 * been updated and watch might have been freed.
411 * So we need to keep a reference of watch.
412 */
413 audit_get_watch(watch);
414
415 mutex_unlock(&audit_filter_mutex);
416
417 /* Avoid calling path_lookup under audit_filter_mutex. */
418 ret = audit_get_nd(watch, &parent_path);
419
420 /* caller expects mutex locked */
421 mutex_lock(&audit_filter_mutex);
422
423 if (ret) {
424 audit_put_watch(watch);
425 return ret;
426 }
427
428 /* either find an old parent or attach a new one */
429 parent = audit_find_parent(d_backing_inode(parent_path.dentry));
430 if (!parent) {
431 parent = audit_init_parent(&parent_path);
432 if (IS_ERR(parent)) {
433 ret = PTR_ERR(parent);
434 goto error;
435 }
436 }
437
438 audit_add_to_parent(krule, parent);
439
440 h = audit_hash_ino((u32)watch->ino);
441 *list = &audit_inode_hash[h];
442error:
443 path_put(&parent_path);
444 audit_put_watch(watch);
445 return ret;
446}
447
448void audit_remove_watch_rule(struct audit_krule *krule)
449{
450 struct audit_watch *watch = krule->watch;
451 struct audit_parent *parent = watch->parent;
452
453 list_del(&krule->rlist);
454
455 if (list_empty(&watch->rules)) {
456 /*
457 * audit_remove_watch() drops our reference to 'parent' which
458 * can get freed. Grab our own reference to be safe.
459 */
460 audit_get_parent(parent);
461 audit_remove_watch(watch);
462 if (list_empty(&parent->watches))
463 fsnotify_destroy_mark(&parent->mark, audit_watch_group);
464 audit_put_parent(parent);
465 }
466}
467
468/* Update watch data in audit rules based on fsnotify events. */
469static int audit_watch_handle_event(struct fsnotify_group *group,
470 struct inode *to_tell,
471 u32 mask, const void *data, int data_type,
472 const struct qstr *dname, u32 cookie,
473 struct fsnotify_iter_info *iter_info)
474{
475 struct fsnotify_mark *inode_mark = fsnotify_iter_inode_mark(iter_info);
476 const struct inode *inode;
477 struct audit_parent *parent;
478
479 parent = container_of(inode_mark, struct audit_parent, mark);
480
481 BUG_ON(group != audit_watch_group);
482
483 switch (data_type) {
484 case (FSNOTIFY_EVENT_PATH):
485 inode = d_backing_inode(((const struct path *)data)->dentry);
486 break;
487 case (FSNOTIFY_EVENT_INODE):
488 inode = (const struct inode *)data;
489 break;
490 default:
491 BUG();
492 inode = NULL;
493 break;
494 }
495
496 if (mask & (FS_CREATE|FS_MOVED_TO) && inode)
497 audit_update_watch(parent, dname, inode->i_sb->s_dev, inode->i_ino, 0);
498 else if (mask & (FS_DELETE|FS_MOVED_FROM))
499 audit_update_watch(parent, dname, AUDIT_DEV_UNSET, AUDIT_INO_UNSET, 1);
500 else if (mask & (FS_DELETE_SELF|FS_UNMOUNT|FS_MOVE_SELF))
501 audit_remove_parent_watches(parent);
502
503 return 0;
504}
505
506static const struct fsnotify_ops audit_watch_fsnotify_ops = {
507 .handle_event = audit_watch_handle_event,
508 .free_mark = audit_watch_free_mark,
509};
510
511static int __init audit_watch_init(void)
512{
513 audit_watch_group = fsnotify_alloc_group(&audit_watch_fsnotify_ops);
514 if (IS_ERR(audit_watch_group)) {
515 audit_watch_group = NULL;
516 audit_panic("cannot create audit fsnotify group");
517 }
518 return 0;
519}
520device_initcall(audit_watch_init);
521
522int audit_dupe_exe(struct audit_krule *new, struct audit_krule *old)
523{
524 struct audit_fsnotify_mark *audit_mark;
525 char *pathname;
526
527 pathname = kstrdup(audit_mark_path(old->exe), GFP_KERNEL);
528 if (!pathname)
529 return -ENOMEM;
530
531 audit_mark = audit_alloc_mark(new, pathname, strlen(pathname));
532 if (IS_ERR(audit_mark)) {
533 kfree(pathname);
534 return PTR_ERR(audit_mark);
535 }
536 new->exe = audit_mark;
537
538 return 0;
539}
540
541int audit_exe_compare(struct task_struct *tsk, struct audit_fsnotify_mark *mark)
542{
543 struct file *exe_file;
544 unsigned long ino;
545 dev_t dev;
546
547 exe_file = get_task_exe_file(tsk);
548 if (!exe_file)
549 return 0;
550 ino = file_inode(exe_file)->i_ino;
551 dev = file_inode(exe_file)->i_sb->s_dev;
552 fput(exe_file);
553 return audit_mark_compare(mark, ino, dev);
554}
1/* audit_watch.c -- watching inodes
2 *
3 * Copyright 2003-2009 Red Hat, Inc.
4 * Copyright 2005 Hewlett-Packard Development Company, L.P.
5 * Copyright 2005 IBM Corporation
6 *
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.
11 *
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.
16 *
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
20 */
21
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"
34
35/*
36 * Reference counting:
37 *
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.
40 *
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.
45 */
46
47struct 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 */
55};
56
57struct audit_parent {
58 struct list_head watches; /* anchor for audit_watch->wlist */
59 struct fsnotify_mark mark; /* fsnotify mark on the inode */
60};
61
62/* fsnotify handle. */
63static struct fsnotify_group *audit_watch_group;
64
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)
68
69static void audit_free_parent(struct audit_parent *parent)
70{
71 WARN_ON(!list_empty(&parent->watches));
72 kfree(parent);
73}
74
75static void audit_watch_free_mark(struct fsnotify_mark *entry)
76{
77 struct audit_parent *parent;
78
79 parent = container_of(entry, struct audit_parent, mark);
80 audit_free_parent(parent);
81}
82
83static void audit_get_parent(struct audit_parent *parent)
84{
85 if (likely(parent))
86 fsnotify_get_mark(&parent->mark);
87}
88
89static void audit_put_parent(struct audit_parent *parent)
90{
91 if (likely(parent))
92 fsnotify_put_mark(&parent->mark);
93}
94
95/*
96 * Find and return the audit_parent on the given inode. If found a reference
97 * is taken on this parent.
98 */
99static inline struct audit_parent *audit_find_parent(struct inode *inode)
100{
101 struct audit_parent *parent = NULL;
102 struct fsnotify_mark *entry;
103
104 entry = fsnotify_find_inode_mark(audit_watch_group, inode);
105 if (entry)
106 parent = container_of(entry, struct audit_parent, mark);
107
108 return parent;
109}
110
111void audit_get_watch(struct audit_watch *watch)
112{
113 atomic_inc(&watch->count);
114}
115
116void audit_put_watch(struct audit_watch *watch)
117{
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);
123 }
124}
125
126static void audit_remove_watch(struct audit_watch *watch)
127{
128 list_del(&watch->wlist);
129 audit_put_parent(watch->parent);
130 watch->parent = NULL;
131 audit_put_watch(watch); /* match initial get */
132}
133
134char *audit_watch_path(struct audit_watch *watch)
135{
136 return watch->path;
137}
138
139int audit_watch_compare(struct audit_watch *watch, unsigned long ino, dev_t dev)
140{
141 return (watch->ino != (unsigned long)-1) &&
142 (watch->ino == ino) &&
143 (watch->dev == dev);
144}
145
146/* Initialize a parent watch entry. */
147static struct audit_parent *audit_init_parent(struct path *path)
148{
149 struct inode *inode = path->dentry->d_inode;
150 struct audit_parent *parent;
151 int ret;
152
153 parent = kzalloc(sizeof(*parent), GFP_KERNEL);
154 if (unlikely(!parent))
155 return ERR_PTR(-ENOMEM);
156
157 INIT_LIST_HEAD(&parent->watches);
158
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);
165 }
166
167 return parent;
168}
169
170/* Initialize a watch entry. */
171static struct audit_watch *audit_init_watch(char *path)
172{
173 struct audit_watch *watch;
174
175 watch = kzalloc(sizeof(*watch), GFP_KERNEL);
176 if (unlikely(!watch))
177 return ERR_PTR(-ENOMEM);
178
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;
184
185 return watch;
186}
187
188/* Translate a watch string to kernel respresentation. */
189int audit_to_watch(struct audit_krule *krule, char *path, int len, u32 op)
190{
191 struct audit_watch *watch;
192
193 if (!audit_watch_group)
194 return -EOPNOTSUPP;
195
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;
201
202 watch = audit_init_watch(path);
203 if (IS_ERR(watch))
204 return PTR_ERR(watch);
205
206 audit_get_watch(watch);
207 krule->watch = watch;
208
209 return 0;
210}
211
212/* Duplicate the given audit watch. The new watch's rules list is initialized
213 * to an empty list and wlist is undefined. */
214static struct audit_watch *audit_dupe_watch(struct audit_watch *old)
215{
216 char *path;
217 struct audit_watch *new;
218
219 path = kstrdup(old->path, GFP_KERNEL);
220 if (unlikely(!path))
221 return ERR_PTR(-ENOMEM);
222
223 new = audit_init_watch(path);
224 if (IS_ERR(new)) {
225 kfree(path);
226 goto out;
227 }
228
229 new->dev = old->dev;
230 new->ino = old->ino;
231 audit_get_parent(old->parent);
232 new->parent = old->parent;
233
234out:
235 return new;
236}
237
238static void audit_watch_log_rule_change(struct audit_krule *r, struct audit_watch *w, char *op)
239{
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);
252 }
253}
254
255/* Update inode info in audit rules based on filesystem event. */
256static void audit_update_watch(struct audit_parent *parent,
257 const char *dname, dev_t dev,
258 unsigned long ino, unsigned invalidating)
259{
260 struct audit_watch *owatch, *nwatch, *nextw;
261 struct audit_krule *r, *nextr;
262 struct audit_entry *oentry, *nentry;
263
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;
270
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);
275
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;
283 }
284 nwatch->dev = dev;
285 nwatch->ino = ino;
286
287 list_for_each_entry_safe(r, nextr, &owatch->rules, rlist) {
288
289 oentry = container_of(r, struct audit_entry, rule);
290 list_del(&oentry->rule.rlist);
291 list_del_rcu(&oentry->list);
292
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);
299
300 /*
301 * nentry->rule.watch == oentry->rule.watch so
302 * we must drop that reference and set it to our
303 * new watch.
304 */
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);
312 }
313
314 audit_watch_log_rule_change(r, owatch, "updated rules");
315
316 call_rcu(&oentry->rcu, audit_free_rule_rcu);
317 }
318
319 audit_remove_watch(owatch);
320 goto add_watch_to_parent; /* event applies to a single watch */
321 }
322 mutex_unlock(&audit_filter_mutex);
323 return;
324
325add_watch_to_parent:
326 list_add(&nwatch->wlist, &parent->watches);
327 mutex_unlock(&audit_filter_mutex);
328 return;
329}
330
331/* Remove all watches & rules associated with a parent that is going away. */
332static void audit_remove_parent_watches(struct audit_parent *parent)
333{
334 struct audit_watch *w, *nextw;
335 struct audit_krule *r, *nextr;
336 struct audit_entry *e;
337
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);
347 }
348 audit_remove_watch(w);
349 }
350 mutex_unlock(&audit_filter_mutex);
351
352 fsnotify_destroy_mark(&parent->mark);
353}
354
355/* Get path information necessary for adding watches. */
356static int audit_get_nd(struct audit_watch *watch, struct path *parent)
357{
358 struct nameidata nd;
359 struct dentry *d;
360 int err;
361
362 err = kern_path_parent(watch->path, &nd);
363 if (err)
364 return err;
365
366 if (nd.last_type != LAST_NORM) {
367 path_put(&nd.path);
368 return -EINVAL;
369 }
370
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);
377 }
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;
382 }
383 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
384
385 *parent = nd.path;
386 dput(d);
387 return 0;
388}
389
390/* Associate the given rule with an existing parent.
391 * Caller must hold audit_filter_mutex. */
392static void audit_add_to_parent(struct audit_krule *krule,
393 struct audit_parent *parent)
394{
395 struct audit_watch *w, *watch = krule->watch;
396 int watch_found = 0;
397
398 BUG_ON(!mutex_is_locked(&audit_filter_mutex));
399
400 list_for_each_entry(w, &parent->watches, wlist) {
401 if (strcmp(watch->path, w->path))
402 continue;
403
404 watch_found = 1;
405
406 /* put krule's and initial refs to temporary watch */
407 audit_put_watch(watch);
408 audit_put_watch(watch);
409
410 audit_get_watch(w);
411 krule->watch = watch = w;
412 break;
413 }
414
415 if (!watch_found) {
416 audit_get_parent(parent);
417 watch->parent = parent;
418
419 list_add(&watch->wlist, &parent->watches);
420 }
421 list_add(&krule->rlist, &watch->rules);
422}
423
424/* Find a matching watch entry, or add this one.
425 * Caller must hold audit_filter_mutex. */
426int audit_add_watch(struct audit_krule *krule, struct list_head **list)
427{
428 struct audit_watch *watch = krule->watch;
429 struct audit_parent *parent;
430 struct path parent_path;
431 int h, ret = 0;
432
433 mutex_unlock(&audit_filter_mutex);
434
435 /* Avoid calling path_lookup under audit_filter_mutex. */
436 ret = audit_get_nd(watch, &parent_path);
437
438 /* caller expects mutex locked */
439 mutex_lock(&audit_filter_mutex);
440
441 if (ret)
442 return ret;
443
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;
451 }
452 }
453
454 audit_add_to_parent(krule, parent);
455
456 /* match get in audit_find_parent or audit_init_parent */
457 audit_put_parent(parent);
458
459 h = audit_hash_ino((u32)watch->ino);
460 *list = &audit_inode_hash[h];
461error:
462 path_put(&parent_path);
463 return ret;
464}
465
466void audit_remove_watch_rule(struct audit_krule *krule)
467{
468 struct audit_watch *watch = krule->watch;
469 struct audit_parent *parent = watch->parent;
470
471 list_del(&krule->rlist);
472
473 if (list_empty(&watch->rules)) {
474 audit_remove_watch(watch);
475
476 if (list_empty(&parent->watches)) {
477 audit_get_parent(parent);
478 fsnotify_destroy_mark(&parent->mark);
479 audit_put_parent(parent);
480 }
481 }
482}
483
484static 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)
488{
489 return true;
490}
491
492/* Update watch data in audit rules based on fsnotify events. */
493static 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)
497{
498 struct inode *inode;
499 __u32 mask = event->mask;
500 const char *dname = event->file_name;
501 struct audit_parent *parent;
502
503 parent = container_of(inode_mark, struct audit_parent, mark);
504
505 BUG_ON(group != audit_watch_group);
506
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;
518 };
519
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);
526
527 return 0;
528}
529
530static 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,
536};
537
538static int __init audit_watch_init(void)
539{
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");
544 }
545 return 0;
546}
547device_initcall(audit_watch_init);