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cfcad62c EP |
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> | |
e9fd702a | 27 | #include <linux/fsnotify_backend.h> |
cfcad62c EP |
28 | #include <linux/namei.h> |
29 | #include <linux/netlink.h> | |
30 | #include <linux/sched.h> | |
5a0e3ad6 | 31 | #include <linux/slab.h> |
cfcad62c EP |
32 | #include <linux/security.h> |
33 | #include "audit.h" | |
34 | ||
35 | /* | |
36 | * Reference counting: | |
37 | * | |
e9fd702a | 38 | * audit_parent: lifetime is from audit_init_parent() to receipt of an FS_IGNORED |
cfcad62c EP |
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 | ||
47 | struct audit_watch { | |
48 | atomic_t count; /* reference count */ | |
cfcad62c | 49 | dev_t dev; /* associated superblock device */ |
e08b061e | 50 | char *path; /* insertion path */ |
cfcad62c EP |
51 | unsigned long ino; /* associated inode number */ |
52 | struct audit_parent *parent; /* associated parent */ | |
53 | struct list_head wlist; /* entry in parent->watches list */ | |
ae7b8f41 | 54 | struct list_head rules; /* anchor for krule->rlist */ |
cfcad62c EP |
55 | }; |
56 | ||
57 | struct audit_parent { | |
ae7b8f41 EP |
58 | struct list_head ilist; /* tmp list used to free parents */ |
59 | struct list_head watches; /* anchor for audit_watch->wlist */ | |
e9fd702a | 60 | struct fsnotify_mark_entry mark; /* fsnotify mark on the inode */ |
cfcad62c EP |
61 | unsigned flags; /* status flags */ |
62 | }; | |
63 | ||
e9fd702a EP |
64 | /* fsnotify handle. */ |
65 | struct fsnotify_group *audit_watch_group; | |
cfcad62c EP |
66 | |
67 | /* | |
68 | * audit_parent status flags: | |
69 | * | |
70 | * AUDIT_PARENT_INVALID - set anytime rules/watches are auto-removed due to | |
71 | * a filesystem event to ensure we're adding audit watches to a valid parent. | |
e9fd702a EP |
72 | * Technically not needed for FS_DELETE_SELF or FS_UNMOUNT events, as we cannot |
73 | * receive them while we have nameidata, but must be used for FS_MOVE_SELF which | |
cfcad62c EP |
74 | * we can receive while holding nameidata. |
75 | */ | |
76 | #define AUDIT_PARENT_INVALID 0x001 | |
77 | ||
e9fd702a EP |
78 | /* fsnotify events we care about. */ |
79 | #define AUDIT_FS_WATCH (FS_MOVE | FS_CREATE | FS_DELETE | FS_DELETE_SELF |\ | |
80 | FS_MOVE_SELF | FS_EVENT_ON_CHILD) | |
cfcad62c | 81 | |
ae7b8f41 EP |
82 | static void audit_free_parent(struct audit_parent *parent) |
83 | { | |
84 | WARN_ON(!list_empty(&parent->watches)); | |
85 | kfree(parent); | |
86 | } | |
87 | ||
e9fd702a | 88 | static void audit_watch_free_mark(struct fsnotify_mark_entry *entry) |
cfcad62c EP |
89 | { |
90 | struct audit_parent *parent; | |
91 | ||
e9fd702a | 92 | parent = container_of(entry, struct audit_parent, mark); |
ae7b8f41 | 93 | audit_free_parent(parent); |
cfcad62c EP |
94 | } |
95 | ||
e9fd702a EP |
96 | static void audit_get_parent(struct audit_parent *parent) |
97 | { | |
98 | if (likely(parent)) | |
99 | fsnotify_get_mark(&parent->mark); | |
100 | } | |
101 | ||
102 | static void audit_put_parent(struct audit_parent *parent) | |
103 | { | |
104 | if (likely(parent)) | |
105 | fsnotify_put_mark(&parent->mark); | |
106 | } | |
107 | ||
108 | /* | |
109 | * Find and return the audit_parent on the given inode. If found a reference | |
110 | * is taken on this parent. | |
111 | */ | |
112 | static inline struct audit_parent *audit_find_parent(struct inode *inode) | |
113 | { | |
114 | struct audit_parent *parent = NULL; | |
115 | struct fsnotify_mark_entry *entry; | |
116 | ||
117 | spin_lock(&inode->i_lock); | |
118 | entry = fsnotify_find_mark_entry(audit_watch_group, inode); | |
119 | spin_unlock(&inode->i_lock); | |
120 | ||
121 | if (entry) | |
122 | parent = container_of(entry, struct audit_parent, mark); | |
123 | ||
124 | return parent; | |
125 | } | |
126 | ||
cfcad62c EP |
127 | void audit_get_watch(struct audit_watch *watch) |
128 | { | |
129 | atomic_inc(&watch->count); | |
130 | } | |
131 | ||
132 | void audit_put_watch(struct audit_watch *watch) | |
133 | { | |
134 | if (atomic_dec_and_test(&watch->count)) { | |
135 | WARN_ON(watch->parent); | |
136 | WARN_ON(!list_empty(&watch->rules)); | |
137 | kfree(watch->path); | |
138 | kfree(watch); | |
139 | } | |
140 | } | |
141 | ||
142 | void audit_remove_watch(struct audit_watch *watch) | |
143 | { | |
144 | list_del(&watch->wlist); | |
e9fd702a | 145 | audit_put_parent(watch->parent); |
cfcad62c EP |
146 | watch->parent = NULL; |
147 | audit_put_watch(watch); /* match initial get */ | |
148 | } | |
149 | ||
150 | char *audit_watch_path(struct audit_watch *watch) | |
151 | { | |
152 | return watch->path; | |
153 | } | |
154 | ||
ae7b8f41 | 155 | int audit_watch_compare(struct audit_watch *watch, unsigned long ino, dev_t dev) |
cfcad62c | 156 | { |
ae7b8f41 EP |
157 | return (watch->ino != (unsigned long)-1) && |
158 | (watch->ino == ino) && | |
159 | (watch->dev == dev); | |
cfcad62c EP |
160 | } |
161 | ||
162 | /* Initialize a parent watch entry. */ | |
163 | static struct audit_parent *audit_init_parent(struct nameidata *ndp) | |
164 | { | |
e9fd702a | 165 | struct inode *inode = ndp->path.dentry->d_inode; |
cfcad62c | 166 | struct audit_parent *parent; |
e9fd702a | 167 | int ret; |
cfcad62c EP |
168 | |
169 | parent = kzalloc(sizeof(*parent), GFP_KERNEL); | |
170 | if (unlikely(!parent)) | |
171 | return ERR_PTR(-ENOMEM); | |
172 | ||
173 | INIT_LIST_HEAD(&parent->watches); | |
174 | parent->flags = 0; | |
175 | ||
e9fd702a EP |
176 | fsnotify_init_mark(&parent->mark, audit_watch_free_mark); |
177 | parent->mark.mask = AUDIT_FS_WATCH; | |
178 | /* grab a ref so fsnotify mark hangs around until we take audit_filter_mutex */ | |
179 | audit_get_parent(parent); | |
180 | ret = fsnotify_add_mark(&parent->mark, audit_watch_group, inode); | |
181 | if (ret < 0) { | |
ae7b8f41 | 182 | audit_free_parent(parent); |
e9fd702a | 183 | return ERR_PTR(ret); |
cfcad62c EP |
184 | } |
185 | ||
186 | return parent; | |
187 | } | |
188 | ||
189 | /* Initialize a watch entry. */ | |
190 | static struct audit_watch *audit_init_watch(char *path) | |
191 | { | |
192 | struct audit_watch *watch; | |
193 | ||
194 | watch = kzalloc(sizeof(*watch), GFP_KERNEL); | |
195 | if (unlikely(!watch)) | |
196 | return ERR_PTR(-ENOMEM); | |
197 | ||
198 | INIT_LIST_HEAD(&watch->rules); | |
199 | atomic_set(&watch->count, 1); | |
200 | watch->path = path; | |
201 | watch->dev = (dev_t)-1; | |
202 | watch->ino = (unsigned long)-1; | |
203 | ||
204 | return watch; | |
205 | } | |
206 | ||
207 | /* Translate a watch string to kernel respresentation. */ | |
208 | int audit_to_watch(struct audit_krule *krule, char *path, int len, u32 op) | |
209 | { | |
210 | struct audit_watch *watch; | |
211 | ||
e9fd702a | 212 | if (!audit_watch_group) |
cfcad62c EP |
213 | return -EOPNOTSUPP; |
214 | ||
215 | if (path[0] != '/' || path[len-1] == '/' || | |
216 | krule->listnr != AUDIT_FILTER_EXIT || | |
217 | op != Audit_equal || | |
218 | krule->inode_f || krule->watch || krule->tree) | |
219 | return -EINVAL; | |
220 | ||
221 | watch = audit_init_watch(path); | |
222 | if (IS_ERR(watch)) | |
223 | return PTR_ERR(watch); | |
224 | ||
225 | audit_get_watch(watch); | |
226 | krule->watch = watch; | |
227 | ||
228 | return 0; | |
229 | } | |
230 | ||
231 | /* Duplicate the given audit watch. The new watch's rules list is initialized | |
232 | * to an empty list and wlist is undefined. */ | |
233 | static struct audit_watch *audit_dupe_watch(struct audit_watch *old) | |
234 | { | |
235 | char *path; | |
236 | struct audit_watch *new; | |
237 | ||
238 | path = kstrdup(old->path, GFP_KERNEL); | |
239 | if (unlikely(!path)) | |
240 | return ERR_PTR(-ENOMEM); | |
241 | ||
242 | new = audit_init_watch(path); | |
243 | if (IS_ERR(new)) { | |
244 | kfree(path); | |
245 | goto out; | |
246 | } | |
247 | ||
248 | new->dev = old->dev; | |
249 | new->ino = old->ino; | |
e9fd702a | 250 | audit_get_parent(old->parent); |
cfcad62c EP |
251 | new->parent = old->parent; |
252 | ||
253 | out: | |
254 | return new; | |
255 | } | |
256 | ||
257 | static void audit_watch_log_rule_change(struct audit_krule *r, struct audit_watch *w, char *op) | |
258 | { | |
259 | if (audit_enabled) { | |
260 | struct audit_buffer *ab; | |
261 | ab = audit_log_start(NULL, GFP_NOFS, AUDIT_CONFIG_CHANGE); | |
262 | audit_log_format(ab, "auid=%u ses=%u op=", | |
263 | audit_get_loginuid(current), | |
264 | audit_get_sessionid(current)); | |
265 | audit_log_string(ab, op); | |
266 | audit_log_format(ab, " path="); | |
267 | audit_log_untrustedstring(ab, w->path); | |
9d960985 | 268 | audit_log_key(ab, r->filterkey); |
cfcad62c EP |
269 | audit_log_format(ab, " list=%d res=1", r->listnr); |
270 | audit_log_end(ab); | |
271 | } | |
272 | } | |
273 | ||
274 | /* Update inode info in audit rules based on filesystem event. */ | |
275 | static void audit_update_watch(struct audit_parent *parent, | |
276 | const char *dname, dev_t dev, | |
277 | unsigned long ino, unsigned invalidating) | |
278 | { | |
279 | struct audit_watch *owatch, *nwatch, *nextw; | |
280 | struct audit_krule *r, *nextr; | |
281 | struct audit_entry *oentry, *nentry; | |
282 | ||
283 | mutex_lock(&audit_filter_mutex); | |
ae7b8f41 EP |
284 | /* Run all of the watches on this parent looking for the one that |
285 | * matches the given dname */ | |
cfcad62c EP |
286 | list_for_each_entry_safe(owatch, nextw, &parent->watches, wlist) { |
287 | if (audit_compare_dname_path(dname, owatch->path, NULL)) | |
288 | continue; | |
289 | ||
290 | /* If the update involves invalidating rules, do the inode-based | |
291 | * filtering now, so we don't omit records. */ | |
ae7b8f41 | 292 | if (invalidating && !audit_dummy_context()) |
cfcad62c EP |
293 | audit_filter_inodes(current, current->audit_context); |
294 | ||
ae7b8f41 EP |
295 | /* updating ino will likely change which audit_hash_list we |
296 | * are on so we need a new watch for the new list */ | |
cfcad62c EP |
297 | nwatch = audit_dupe_watch(owatch); |
298 | if (IS_ERR(nwatch)) { | |
299 | mutex_unlock(&audit_filter_mutex); | |
300 | audit_panic("error updating watch, skipping"); | |
301 | return; | |
302 | } | |
303 | nwatch->dev = dev; | |
304 | nwatch->ino = ino; | |
305 | ||
306 | list_for_each_entry_safe(r, nextr, &owatch->rules, rlist) { | |
307 | ||
308 | oentry = container_of(r, struct audit_entry, rule); | |
309 | list_del(&oentry->rule.rlist); | |
310 | list_del_rcu(&oentry->list); | |
311 | ||
ae7b8f41 | 312 | nentry = audit_dupe_rule(&oentry->rule); |
cfcad62c EP |
313 | if (IS_ERR(nentry)) { |
314 | list_del(&oentry->rule.list); | |
315 | audit_panic("error updating watch, removing"); | |
316 | } else { | |
317 | int h = audit_hash_ino((u32)ino); | |
ae7b8f41 EP |
318 | |
319 | /* | |
320 | * nentry->rule.watch == oentry->rule.watch so | |
321 | * we must drop that reference and set it to our | |
322 | * new watch. | |
323 | */ | |
324 | audit_put_watch(nentry->rule.watch); | |
325 | audit_get_watch(nwatch); | |
326 | nentry->rule.watch = nwatch; | |
cfcad62c EP |
327 | list_add(&nentry->rule.rlist, &nwatch->rules); |
328 | list_add_rcu(&nentry->list, &audit_inode_hash[h]); | |
329 | list_replace(&oentry->rule.list, | |
330 | &nentry->rule.list); | |
331 | } | |
332 | ||
333 | audit_watch_log_rule_change(r, owatch, "updated rules"); | |
334 | ||
335 | call_rcu(&oentry->rcu, audit_free_rule_rcu); | |
336 | } | |
337 | ||
338 | audit_remove_watch(owatch); | |
339 | goto add_watch_to_parent; /* event applies to a single watch */ | |
340 | } | |
341 | mutex_unlock(&audit_filter_mutex); | |
342 | return; | |
343 | ||
344 | add_watch_to_parent: | |
345 | list_add(&nwatch->wlist, &parent->watches); | |
346 | mutex_unlock(&audit_filter_mutex); | |
347 | return; | |
348 | } | |
349 | ||
350 | /* Remove all watches & rules associated with a parent that is going away. */ | |
351 | static void audit_remove_parent_watches(struct audit_parent *parent) | |
352 | { | |
353 | struct audit_watch *w, *nextw; | |
354 | struct audit_krule *r, *nextr; | |
355 | struct audit_entry *e; | |
356 | ||
357 | mutex_lock(&audit_filter_mutex); | |
358 | parent->flags |= AUDIT_PARENT_INVALID; | |
359 | list_for_each_entry_safe(w, nextw, &parent->watches, wlist) { | |
360 | list_for_each_entry_safe(r, nextr, &w->rules, rlist) { | |
361 | e = container_of(r, struct audit_entry, rule); | |
362 | audit_watch_log_rule_change(r, w, "remove rule"); | |
363 | list_del(&r->rlist); | |
364 | list_del(&r->list); | |
365 | list_del_rcu(&e->list); | |
366 | call_rcu(&e->rcu, audit_free_rule_rcu); | |
367 | } | |
368 | audit_remove_watch(w); | |
369 | } | |
370 | mutex_unlock(&audit_filter_mutex); | |
e9fd702a EP |
371 | |
372 | fsnotify_destroy_mark_by_entry(&parent->mark); | |
cfcad62c EP |
373 | } |
374 | ||
375 | /* Unregister inotify watches for parents on in_list. | |
e9fd702a | 376 | * Generates an FS_IGNORED event. */ |
ae7b8f41 | 377 | void audit_watch_inotify_unregister(struct list_head *in_list) |
cfcad62c EP |
378 | { |
379 | struct audit_parent *p, *n; | |
380 | ||
381 | list_for_each_entry_safe(p, n, in_list, ilist) { | |
382 | list_del(&p->ilist); | |
e9fd702a EP |
383 | fsnotify_destroy_mark_by_entry(&p->mark); |
384 | /* matches the get in audit_remove_watch_rule() */ | |
385 | audit_put_parent(p); | |
cfcad62c EP |
386 | } |
387 | } | |
388 | ||
389 | /* Get path information necessary for adding watches. */ | |
35fe4d0b | 390 | static int audit_get_nd(char *path, struct nameidata **ndp, struct nameidata **ndw) |
cfcad62c EP |
391 | { |
392 | struct nameidata *ndparent, *ndwatch; | |
393 | int err; | |
394 | ||
395 | ndparent = kmalloc(sizeof(*ndparent), GFP_KERNEL); | |
396 | if (unlikely(!ndparent)) | |
397 | return -ENOMEM; | |
398 | ||
399 | ndwatch = kmalloc(sizeof(*ndwatch), GFP_KERNEL); | |
400 | if (unlikely(!ndwatch)) { | |
401 | kfree(ndparent); | |
402 | return -ENOMEM; | |
403 | } | |
404 | ||
405 | err = path_lookup(path, LOOKUP_PARENT, ndparent); | |
406 | if (err) { | |
407 | kfree(ndparent); | |
408 | kfree(ndwatch); | |
409 | return err; | |
410 | } | |
411 | ||
412 | err = path_lookup(path, 0, ndwatch); | |
413 | if (err) { | |
414 | kfree(ndwatch); | |
415 | ndwatch = NULL; | |
416 | } | |
417 | ||
418 | *ndp = ndparent; | |
419 | *ndw = ndwatch; | |
420 | ||
421 | return 0; | |
422 | } | |
423 | ||
424 | /* Release resources used for watch path information. */ | |
35fe4d0b | 425 | static void audit_put_nd(struct nameidata *ndp, struct nameidata *ndw) |
cfcad62c EP |
426 | { |
427 | if (ndp) { | |
428 | path_put(&ndp->path); | |
429 | kfree(ndp); | |
430 | } | |
431 | if (ndw) { | |
432 | path_put(&ndw->path); | |
433 | kfree(ndw); | |
434 | } | |
435 | } | |
436 | ||
e9fd702a | 437 | /* Associate the given rule with an existing parent. |
cfcad62c EP |
438 | * Caller must hold audit_filter_mutex. */ |
439 | static void audit_add_to_parent(struct audit_krule *krule, | |
440 | struct audit_parent *parent) | |
441 | { | |
442 | struct audit_watch *w, *watch = krule->watch; | |
443 | int watch_found = 0; | |
444 | ||
e9fd702a EP |
445 | BUG_ON(!mutex_is_locked(&audit_filter_mutex)); |
446 | ||
cfcad62c EP |
447 | list_for_each_entry(w, &parent->watches, wlist) { |
448 | if (strcmp(watch->path, w->path)) | |
449 | continue; | |
450 | ||
451 | watch_found = 1; | |
452 | ||
453 | /* put krule's and initial refs to temporary watch */ | |
454 | audit_put_watch(watch); | |
455 | audit_put_watch(watch); | |
456 | ||
457 | audit_get_watch(w); | |
458 | krule->watch = watch = w; | |
459 | break; | |
460 | } | |
461 | ||
462 | if (!watch_found) { | |
e9fd702a | 463 | audit_get_parent(parent); |
cfcad62c EP |
464 | watch->parent = parent; |
465 | ||
466 | list_add(&watch->wlist, &parent->watches); | |
467 | } | |
468 | list_add(&krule->rlist, &watch->rules); | |
469 | } | |
470 | ||
471 | /* Find a matching watch entry, or add this one. | |
472 | * Caller must hold audit_filter_mutex. */ | |
ae7b8f41 | 473 | int audit_add_watch(struct audit_krule *krule, struct list_head **list) |
cfcad62c EP |
474 | { |
475 | struct audit_watch *watch = krule->watch; | |
cfcad62c | 476 | struct audit_parent *parent; |
35fe4d0b | 477 | struct nameidata *ndp = NULL, *ndw = NULL; |
ae7b8f41 | 478 | int h, ret = 0; |
cfcad62c | 479 | |
35fe4d0b EP |
480 | mutex_unlock(&audit_filter_mutex); |
481 | ||
482 | /* Avoid calling path_lookup under audit_filter_mutex. */ | |
483 | ret = audit_get_nd(watch->path, &ndp, &ndw); | |
484 | if (ret) { | |
485 | /* caller expects mutex locked */ | |
486 | mutex_lock(&audit_filter_mutex); | |
487 | goto error; | |
488 | } | |
489 | ||
cfcad62c EP |
490 | /* update watch filter fields */ |
491 | if (ndw) { | |
492 | watch->dev = ndw->path.dentry->d_inode->i_sb->s_dev; | |
493 | watch->ino = ndw->path.dentry->d_inode->i_ino; | |
494 | } | |
495 | ||
496 | /* The audit_filter_mutex must not be held during inotify calls because | |
497 | * we hold it during inotify event callback processing. If an existing | |
498 | * inotify watch is found, inotify_find_watch() grabs a reference before | |
499 | * returning. | |
500 | */ | |
e9fd702a EP |
501 | parent = audit_find_parent(ndp->path.dentry->d_inode); |
502 | if (!parent) { | |
cfcad62c EP |
503 | parent = audit_init_parent(ndp); |
504 | if (IS_ERR(parent)) { | |
505 | /* caller expects mutex locked */ | |
506 | mutex_lock(&audit_filter_mutex); | |
35fe4d0b EP |
507 | ret = PTR_ERR(parent); |
508 | goto error; | |
cfcad62c | 509 | } |
e9fd702a | 510 | } |
cfcad62c EP |
511 | |
512 | mutex_lock(&audit_filter_mutex); | |
513 | ||
514 | /* parent was moved before we took audit_filter_mutex */ | |
515 | if (parent->flags & AUDIT_PARENT_INVALID) | |
516 | ret = -ENOENT; | |
517 | else | |
518 | audit_add_to_parent(krule, parent); | |
519 | ||
e9fd702a EP |
520 | /* match get in audit_find_parent or audit_init_parent */ |
521 | audit_put_parent(parent); | |
35fe4d0b | 522 | |
ae7b8f41 EP |
523 | h = audit_hash_ino((u32)watch->ino); |
524 | *list = &audit_inode_hash[h]; | |
35fe4d0b EP |
525 | error: |
526 | audit_put_nd(ndp, ndw); /* NULL args OK */ | |
cfcad62c | 527 | return ret; |
35fe4d0b | 528 | |
cfcad62c EP |
529 | } |
530 | ||
531 | void audit_remove_watch_rule(struct audit_krule *krule, struct list_head *list) | |
532 | { | |
533 | struct audit_watch *watch = krule->watch; | |
534 | struct audit_parent *parent = watch->parent; | |
535 | ||
536 | list_del(&krule->rlist); | |
537 | ||
538 | if (list_empty(&watch->rules)) { | |
539 | audit_remove_watch(watch); | |
540 | ||
541 | if (list_empty(&parent->watches)) { | |
e9fd702a EP |
542 | /* Put parent on the un-registration list. |
543 | * Grab a reference before releasing | |
cfcad62c | 544 | * audit_filter_mutex, to be released in |
e9fd702a | 545 | * audit_watch_inotify_unregister(). |
cfcad62c EP |
546 | * If filesystem is going away, just leave |
547 | * the sucker alone, eviction will take | |
548 | * care of it. */ | |
e9fd702a EP |
549 | audit_get_parent(parent); |
550 | list_add(&parent->ilist, list); | |
cfcad62c EP |
551 | } |
552 | } | |
553 | } | |
554 | ||
e9fd702a | 555 | static bool audit_watch_should_send_event(struct fsnotify_group *group, struct inode *inode, __u32 mask) |
cfcad62c | 556 | { |
e9fd702a EP |
557 | struct fsnotify_mark_entry *entry; |
558 | bool send; | |
559 | ||
560 | spin_lock(&inode->i_lock); | |
561 | entry = fsnotify_find_mark_entry(group, inode); | |
562 | spin_unlock(&inode->i_lock); | |
563 | if (!entry) | |
564 | return false; | |
565 | ||
566 | mask = (mask & ~FS_EVENT_ON_CHILD); | |
567 | send = (entry->mask & mask); | |
568 | ||
569 | /* find took a reference */ | |
570 | fsnotify_put_mark(entry); | |
571 | ||
572 | return send; | |
573 | } | |
574 | ||
575 | /* Update watch data in audit rules based on fsnotify events. */ | |
576 | static int audit_watch_handle_event(struct fsnotify_group *group, struct fsnotify_event *event) | |
577 | { | |
578 | struct inode *inode; | |
579 | __u32 mask = event->mask; | |
580 | const char *dname = event->file_name; | |
cfcad62c EP |
581 | struct audit_parent *parent; |
582 | ||
e9fd702a EP |
583 | BUG_ON(group != audit_watch_group); |
584 | ||
585 | parent = audit_find_parent(event->to_tell); | |
586 | if (unlikely(!parent)) | |
587 | return 0; | |
588 | ||
589 | switch (event->data_type) { | |
590 | case (FSNOTIFY_EVENT_PATH): | |
591 | inode = event->path.dentry->d_inode; | |
592 | break; | |
593 | case (FSNOTIFY_EVENT_INODE): | |
594 | inode = event->inode; | |
595 | break; | |
596 | default: | |
597 | BUG(); | |
598 | inode = NULL; | |
599 | break; | |
600 | }; | |
cfcad62c | 601 | |
e9fd702a | 602 | if (mask & (FS_CREATE|FS_MOVED_TO) && inode) |
ae7b8f41 | 603 | audit_update_watch(parent, dname, inode->i_sb->s_dev, inode->i_ino, 0); |
e9fd702a | 604 | else if (mask & (FS_DELETE|FS_MOVED_FROM)) |
cfcad62c | 605 | audit_update_watch(parent, dname, (dev_t)-1, (unsigned long)-1, 1); |
e9fd702a | 606 | else if (mask & (FS_DELETE_SELF|FS_UNMOUNT|FS_MOVE_SELF)) |
cfcad62c | 607 | audit_remove_parent_watches(parent); |
e9fd702a EP |
608 | /* moved put_inotify_watch to freeing mark */ |
609 | ||
610 | /* matched the ref taken by audit_find_parent */ | |
611 | audit_put_parent(parent); | |
612 | ||
613 | return 0; | |
614 | } | |
615 | ||
616 | static void audit_watch_freeing_mark(struct fsnotify_mark_entry *entry, struct fsnotify_group *group) | |
617 | { | |
618 | struct audit_parent *parent; | |
619 | ||
620 | parent = container_of(entry, struct audit_parent, mark); | |
621 | /* taken from audit_handle_ievent & FS_IGNORED please figure out what I match... */ | |
622 | audit_put_parent(parent); | |
cfcad62c EP |
623 | } |
624 | ||
e9fd702a EP |
625 | static const struct fsnotify_ops audit_watch_fsnotify_ops = { |
626 | .should_send_event = audit_watch_should_send_event, | |
627 | .handle_event = audit_watch_handle_event, | |
628 | .free_group_priv = NULL, | |
629 | .freeing_mark = audit_watch_freeing_mark, | |
630 | .free_event_priv = NULL, | |
cfcad62c EP |
631 | }; |
632 | ||
633 | static int __init audit_watch_init(void) | |
634 | { | |
e9fd702a EP |
635 | audit_watch_group = fsnotify_obtain_group(AUDIT_WATCH_GROUP_NUM, AUDIT_FS_WATCH, |
636 | &audit_watch_fsnotify_ops); | |
637 | if (IS_ERR(audit_watch_group)) { | |
638 | audit_watch_group = NULL; | |
639 | audit_panic("cannot create audit fsnotify group"); | |
640 | } | |
cfcad62c EP |
641 | return 0; |
642 | } | |
643 | subsys_initcall(audit_watch_init); |