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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 != AUDIT_INO_UNSET) &&
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 = d_backing_inode(path->dentry);
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 = AUDIT_DEV_UNSET;
183 watch->ino = AUDIT_INO_UNSET;
184
185 return watch;
186}
187
188/* Translate a watch string to kernel representation. */
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 krule->watch = watch;
207
208 return 0;
209}
210
211/* Duplicate the given audit watch. The new watch's rules list is initialized
212 * to an empty list and wlist is undefined. */
213static struct audit_watch *audit_dupe_watch(struct audit_watch *old)
214{
215 char *path;
216 struct audit_watch *new;
217
218 path = kstrdup(old->path, GFP_KERNEL);
219 if (unlikely(!path))
220 return ERR_PTR(-ENOMEM);
221
222 new = audit_init_watch(path);
223 if (IS_ERR(new)) {
224 kfree(path);
225 goto out;
226 }
227
228 new->dev = old->dev;
229 new->ino = old->ino;
230 audit_get_parent(old->parent);
231 new->parent = old->parent;
232
233out:
234 return new;
235}
236
237static void audit_watch_log_rule_change(struct audit_krule *r, struct audit_watch *w, char *op)
238{
239 if (audit_enabled) {
240 struct audit_buffer *ab;
241 ab = audit_log_start(NULL, GFP_NOFS, AUDIT_CONFIG_CHANGE);
242 if (unlikely(!ab))
243 return;
244 audit_log_format(ab, "auid=%u ses=%u op=",
245 from_kuid(&init_user_ns, audit_get_loginuid(current)),
246 audit_get_sessionid(current));
247 audit_log_string(ab, op);
248 audit_log_format(ab, " path=");
249 audit_log_untrustedstring(ab, w->path);
250 audit_log_key(ab, r->filterkey);
251 audit_log_format(ab, " list=%d res=1", r->listnr);
252 audit_log_end(ab);
253 }
254}
255
256/* Update inode info in audit rules based on filesystem event. */
257static void audit_update_watch(struct audit_parent *parent,
258 const char *dname, dev_t dev,
259 unsigned long ino, unsigned invalidating)
260{
261 struct audit_watch *owatch, *nwatch, *nextw;
262 struct audit_krule *r, *nextr;
263 struct audit_entry *oentry, *nentry;
264
265 mutex_lock(&audit_filter_mutex);
266 /* Run all of the watches on this parent looking for the one that
267 * matches the given dname */
268 list_for_each_entry_safe(owatch, nextw, &parent->watches, wlist) {
269 if (audit_compare_dname_path(dname, owatch->path,
270 AUDIT_NAME_FULL))
271 continue;
272
273 /* If the update involves invalidating rules, do the inode-based
274 * filtering now, so we don't omit records. */
275 if (invalidating && !audit_dummy_context())
276 audit_filter_inodes(current, current->audit_context);
277
278 /* updating ino will likely change which audit_hash_list we
279 * are on so we need a new watch for the new list */
280 nwatch = audit_dupe_watch(owatch);
281 if (IS_ERR(nwatch)) {
282 mutex_unlock(&audit_filter_mutex);
283 audit_panic("error updating watch, skipping");
284 return;
285 }
286 nwatch->dev = dev;
287 nwatch->ino = ino;
288
289 list_for_each_entry_safe(r, nextr, &owatch->rules, rlist) {
290
291 oentry = container_of(r, struct audit_entry, rule);
292 list_del(&oentry->rule.rlist);
293 list_del_rcu(&oentry->list);
294
295 nentry = audit_dupe_rule(&oentry->rule);
296 if (IS_ERR(nentry)) {
297 list_del(&oentry->rule.list);
298 audit_panic("error updating watch, removing");
299 } else {
300 int h = audit_hash_ino((u32)ino);
301
302 /*
303 * nentry->rule.watch == oentry->rule.watch so
304 * we must drop that reference and set it to our
305 * new watch.
306 */
307 audit_put_watch(nentry->rule.watch);
308 audit_get_watch(nwatch);
309 nentry->rule.watch = nwatch;
310 list_add(&nentry->rule.rlist, &nwatch->rules);
311 list_add_rcu(&nentry->list, &audit_inode_hash[h]);
312 list_replace(&oentry->rule.list,
313 &nentry->rule.list);
314 }
315 if (oentry->rule.exe)
316 audit_remove_mark(oentry->rule.exe);
317
318 audit_watch_log_rule_change(r, owatch, "updated_rules");
319
320 call_rcu(&oentry->rcu, audit_free_rule_rcu);
321 }
322
323 audit_remove_watch(owatch);
324 goto add_watch_to_parent; /* event applies to a single watch */
325 }
326 mutex_unlock(&audit_filter_mutex);
327 return;
328
329add_watch_to_parent:
330 list_add(&nwatch->wlist, &parent->watches);
331 mutex_unlock(&audit_filter_mutex);
332 return;
333}
334
335/* Remove all watches & rules associated with a parent that is going away. */
336static void audit_remove_parent_watches(struct audit_parent *parent)
337{
338 struct audit_watch *w, *nextw;
339 struct audit_krule *r, *nextr;
340 struct audit_entry *e;
341
342 mutex_lock(&audit_filter_mutex);
343 list_for_each_entry_safe(w, nextw, &parent->watches, wlist) {
344 list_for_each_entry_safe(r, nextr, &w->rules, rlist) {
345 e = container_of(r, struct audit_entry, rule);
346 audit_watch_log_rule_change(r, w, "remove_rule");
347 if (e->rule.exe)
348 audit_remove_mark(e->rule.exe);
349 list_del(&r->rlist);
350 list_del(&r->list);
351 list_del_rcu(&e->list);
352 call_rcu(&e->rcu, audit_free_rule_rcu);
353 }
354 audit_remove_watch(w);
355 }
356 mutex_unlock(&audit_filter_mutex);
357
358 fsnotify_destroy_mark(&parent->mark, audit_watch_group);
359}
360
361/* Get path information necessary for adding watches. */
362static int audit_get_nd(struct audit_watch *watch, struct path *parent)
363{
364 struct dentry *d = kern_path_locked(watch->path, parent);
365 if (IS_ERR(d))
366 return PTR_ERR(d);
367 inode_unlock(d_backing_inode(parent->dentry));
368 if (d_is_positive(d)) {
369 /* update watch filter fields */
370 watch->dev = d_backing_inode(d)->i_sb->s_dev;
371 watch->ino = d_backing_inode(d)->i_ino;
372 }
373 dput(d);
374 return 0;
375}
376
377/* Associate the given rule with an existing parent.
378 * Caller must hold audit_filter_mutex. */
379static void audit_add_to_parent(struct audit_krule *krule,
380 struct audit_parent *parent)
381{
382 struct audit_watch *w, *watch = krule->watch;
383 int watch_found = 0;
384
385 BUG_ON(!mutex_is_locked(&audit_filter_mutex));
386
387 list_for_each_entry(w, &parent->watches, wlist) {
388 if (strcmp(watch->path, w->path))
389 continue;
390
391 watch_found = 1;
392
393 /* put krule's ref to temporary watch */
394 audit_put_watch(watch);
395
396 audit_get_watch(w);
397 krule->watch = watch = w;
398
399 audit_put_parent(parent);
400 break;
401 }
402
403 if (!watch_found) {
404 watch->parent = parent;
405
406 audit_get_watch(watch);
407 list_add(&watch->wlist, &parent->watches);
408 }
409 list_add(&krule->rlist, &watch->rules);
410}
411
412/* Find a matching watch entry, or add this one.
413 * Caller must hold audit_filter_mutex. */
414int audit_add_watch(struct audit_krule *krule, struct list_head **list)
415{
416 struct audit_watch *watch = krule->watch;
417 struct audit_parent *parent;
418 struct path parent_path;
419 int h, ret = 0;
420
421 mutex_unlock(&audit_filter_mutex);
422
423 /* Avoid calling path_lookup under audit_filter_mutex. */
424 ret = audit_get_nd(watch, &parent_path);
425
426 /* caller expects mutex locked */
427 mutex_lock(&audit_filter_mutex);
428
429 if (ret)
430 return ret;
431
432 /* either find an old parent or attach a new one */
433 parent = audit_find_parent(d_backing_inode(parent_path.dentry));
434 if (!parent) {
435 parent = audit_init_parent(&parent_path);
436 if (IS_ERR(parent)) {
437 ret = PTR_ERR(parent);
438 goto error;
439 }
440 }
441
442 audit_add_to_parent(krule, parent);
443
444 h = audit_hash_ino((u32)watch->ino);
445 *list = &audit_inode_hash[h];
446error:
447 path_put(&parent_path);
448 return ret;
449}
450
451void audit_remove_watch_rule(struct audit_krule *krule)
452{
453 struct audit_watch *watch = krule->watch;
454 struct audit_parent *parent = watch->parent;
455
456 list_del(&krule->rlist);
457
458 if (list_empty(&watch->rules)) {
459 audit_remove_watch(watch);
460
461 if (list_empty(&parent->watches)) {
462 audit_get_parent(parent);
463 fsnotify_destroy_mark(&parent->mark, audit_watch_group);
464 audit_put_parent(parent);
465 }
466 }
467}
468
469/* Update watch data in audit rules based on fsnotify events. */
470static int audit_watch_handle_event(struct fsnotify_group *group,
471 struct inode *to_tell,
472 struct fsnotify_mark *inode_mark,
473 struct fsnotify_mark *vfsmount_mark,
474 u32 mask, void *data, int data_type,
475 const unsigned char *dname, u32 cookie)
476{
477 struct inode *inode;
478 struct audit_parent *parent;
479
480 parent = container_of(inode_mark, struct audit_parent, mark);
481
482 BUG_ON(group != audit_watch_group);
483
484 switch (data_type) {
485 case (FSNOTIFY_EVENT_PATH):
486 inode = d_backing_inode(((struct path *)data)->dentry);
487 break;
488 case (FSNOTIFY_EVENT_INODE):
489 inode = (struct inode *)data;
490 break;
491 default:
492 BUG();
493 inode = NULL;
494 break;
495 };
496
497 if (mask & (FS_CREATE|FS_MOVED_TO) && inode)
498 audit_update_watch(parent, dname, inode->i_sb->s_dev, inode->i_ino, 0);
499 else if (mask & (FS_DELETE|FS_MOVED_FROM))
500 audit_update_watch(parent, dname, AUDIT_DEV_UNSET, AUDIT_INO_UNSET, 1);
501 else if (mask & (FS_DELETE_SELF|FS_UNMOUNT|FS_MOVE_SELF))
502 audit_remove_parent_watches(parent);
503
504 return 0;
505}
506
507static const struct fsnotify_ops audit_watch_fsnotify_ops = {
508 .handle_event = audit_watch_handle_event,
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 rcu_read_lock();
548 exe_file = rcu_dereference(tsk->mm->exe_file);
549 ino = exe_file->f_inode->i_ino;
550 dev = exe_file->f_inode->i_sb->s_dev;
551 rcu_read_unlock();
552 return audit_mark_compare(mark, ino, dev);
553}
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_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 call_rcu(&oentry->rcu, audit_free_rule_rcu);
306 }
307
308 audit_remove_watch(owatch);
309 goto add_watch_to_parent; /* event applies to a single watch */
310 }
311 mutex_unlock(&audit_filter_mutex);
312 return;
313
314add_watch_to_parent:
315 list_add(&nwatch->wlist, &parent->watches);
316 mutex_unlock(&audit_filter_mutex);
317 return;
318}
319
320/* Remove all watches & rules associated with a parent that is going away. */
321static void audit_remove_parent_watches(struct audit_parent *parent)
322{
323 struct audit_watch *w, *nextw;
324 struct audit_krule *r, *nextr;
325 struct audit_entry *e;
326
327 mutex_lock(&audit_filter_mutex);
328 list_for_each_entry_safe(w, nextw, &parent->watches, wlist) {
329 list_for_each_entry_safe(r, nextr, &w->rules, rlist) {
330 e = container_of(r, struct audit_entry, rule);
331 audit_watch_log_rule_change(r, w, "remove_rule");
332 if (e->rule.exe)
333 audit_remove_mark(e->rule.exe);
334 list_del(&r->rlist);
335 list_del(&r->list);
336 list_del_rcu(&e->list);
337 call_rcu(&e->rcu, audit_free_rule_rcu);
338 }
339 audit_remove_watch(w);
340 }
341 mutex_unlock(&audit_filter_mutex);
342
343 fsnotify_destroy_mark(&parent->mark, audit_watch_group);
344}
345
346/* Get path information necessary for adding watches. */
347static int audit_get_nd(struct audit_watch *watch, struct path *parent)
348{
349 struct dentry *d = kern_path_locked(watch->path, parent);
350 if (IS_ERR(d))
351 return PTR_ERR(d);
352 if (d_is_positive(d)) {
353 /* update watch filter fields */
354 watch->dev = d->d_sb->s_dev;
355 watch->ino = d_backing_inode(d)->i_ino;
356 }
357 inode_unlock(d_backing_inode(parent->dentry));
358 dput(d);
359 return 0;
360}
361
362/* Associate the given rule with an existing parent.
363 * Caller must hold audit_filter_mutex. */
364static void audit_add_to_parent(struct audit_krule *krule,
365 struct audit_parent *parent)
366{
367 struct audit_watch *w, *watch = krule->watch;
368 int watch_found = 0;
369
370 BUG_ON(!mutex_is_locked(&audit_filter_mutex));
371
372 list_for_each_entry(w, &parent->watches, wlist) {
373 if (strcmp(watch->path, w->path))
374 continue;
375
376 watch_found = 1;
377
378 /* put krule's ref to temporary watch */
379 audit_put_watch(watch);
380
381 audit_get_watch(w);
382 krule->watch = watch = w;
383
384 audit_put_parent(parent);
385 break;
386 }
387
388 if (!watch_found) {
389 watch->parent = parent;
390
391 audit_get_watch(watch);
392 list_add(&watch->wlist, &parent->watches);
393 }
394 list_add(&krule->rlist, &watch->rules);
395}
396
397/* Find a matching watch entry, or add this one.
398 * Caller must hold audit_filter_mutex. */
399int audit_add_watch(struct audit_krule *krule, struct list_head **list)
400{
401 struct audit_watch *watch = krule->watch;
402 struct audit_parent *parent;
403 struct path parent_path;
404 int h, ret = 0;
405
406 /*
407 * When we will be calling audit_add_to_parent, krule->watch might have
408 * been updated and watch might have been freed.
409 * So we need to keep a reference of watch.
410 */
411 audit_get_watch(watch);
412
413 mutex_unlock(&audit_filter_mutex);
414
415 /* Avoid calling path_lookup under audit_filter_mutex. */
416 ret = audit_get_nd(watch, &parent_path);
417
418 /* caller expects mutex locked */
419 mutex_lock(&audit_filter_mutex);
420
421 if (ret) {
422 audit_put_watch(watch);
423 return ret;
424 }
425
426 /* either find an old parent or attach a new one */
427 parent = audit_find_parent(d_backing_inode(parent_path.dentry));
428 if (!parent) {
429 parent = audit_init_parent(&parent_path);
430 if (IS_ERR(parent)) {
431 ret = PTR_ERR(parent);
432 goto error;
433 }
434 }
435
436 audit_add_to_parent(krule, parent);
437
438 h = audit_hash_ino((u32)watch->ino);
439 *list = &audit_inode_hash[h];
440error:
441 path_put(&parent_path);
442 audit_put_watch(watch);
443 return ret;
444}
445
446void audit_remove_watch_rule(struct audit_krule *krule)
447{
448 struct audit_watch *watch = krule->watch;
449 struct audit_parent *parent = watch->parent;
450
451 list_del(&krule->rlist);
452
453 if (list_empty(&watch->rules)) {
454 /*
455 * audit_remove_watch() drops our reference to 'parent' which
456 * can get freed. Grab our own reference to be safe.
457 */
458 audit_get_parent(parent);
459 audit_remove_watch(watch);
460 if (list_empty(&parent->watches))
461 fsnotify_destroy_mark(&parent->mark, audit_watch_group);
462 audit_put_parent(parent);
463 }
464}
465
466/* Update watch data in audit rules based on fsnotify events. */
467static int audit_watch_handle_event(struct fsnotify_mark *inode_mark, u32 mask,
468 struct inode *inode, struct inode *dir,
469 const struct qstr *dname, u32 cookie)
470{
471 struct audit_parent *parent;
472
473 parent = container_of(inode_mark, struct audit_parent, mark);
474
475 if (WARN_ON_ONCE(inode_mark->group != audit_watch_group) ||
476 WARN_ON_ONCE(!inode))
477 return 0;
478
479 if (mask & (FS_CREATE|FS_MOVED_TO) && inode)
480 audit_update_watch(parent, dname, inode->i_sb->s_dev, inode->i_ino, 0);
481 else if (mask & (FS_DELETE|FS_MOVED_FROM))
482 audit_update_watch(parent, dname, AUDIT_DEV_UNSET, AUDIT_INO_UNSET, 1);
483 else if (mask & (FS_DELETE_SELF|FS_UNMOUNT|FS_MOVE_SELF))
484 audit_remove_parent_watches(parent);
485
486 return 0;
487}
488
489static const struct fsnotify_ops audit_watch_fsnotify_ops = {
490 .handle_inode_event = audit_watch_handle_event,
491 .free_mark = audit_watch_free_mark,
492};
493
494static int __init audit_watch_init(void)
495{
496 audit_watch_group = fsnotify_alloc_group(&audit_watch_fsnotify_ops);
497 if (IS_ERR(audit_watch_group)) {
498 audit_watch_group = NULL;
499 audit_panic("cannot create audit fsnotify group");
500 }
501 return 0;
502}
503device_initcall(audit_watch_init);
504
505int audit_dupe_exe(struct audit_krule *new, struct audit_krule *old)
506{
507 struct audit_fsnotify_mark *audit_mark;
508 char *pathname;
509
510 pathname = kstrdup(audit_mark_path(old->exe), GFP_KERNEL);
511 if (!pathname)
512 return -ENOMEM;
513
514 audit_mark = audit_alloc_mark(new, pathname, strlen(pathname));
515 if (IS_ERR(audit_mark)) {
516 kfree(pathname);
517 return PTR_ERR(audit_mark);
518 }
519 new->exe = audit_mark;
520
521 return 0;
522}
523
524int audit_exe_compare(struct task_struct *tsk, struct audit_fsnotify_mark *mark)
525{
526 struct file *exe_file;
527 unsigned long ino;
528 dev_t dev;
529
530 exe_file = get_task_exe_file(tsk);
531 if (!exe_file)
532 return 0;
533 ino = file_inode(exe_file)->i_ino;
534 dev = file_inode(exe_file)->i_sb->s_dev;
535 fput(exe_file);
536 return audit_mark_compare(mark, ino, dev);
537}