Merge remote-tracking branch 'rcu/rcu/next'
[deliverable/linux.git] / kernel / audit_watch.c
CommitLineData
cfcad62c
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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
5efc2443 22#include <linux/file.h>
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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>
e9fd702a 28#include <linux/fsnotify_backend.h>
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29#include <linux/namei.h>
30#include <linux/netlink.h>
31#include <linux/sched.h>
5a0e3ad6 32#include <linux/slab.h>
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33#include <linux/security.h>
34#include "audit.h"
35
36/*
37 * Reference counting:
38 *
e9fd702a 39 * audit_parent: lifetime is from audit_init_parent() to receipt of an FS_IGNORED
cfcad62c
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40 * event. Each audit_watch holds a reference to its associated parent.
41 *
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.
46 */
47
48struct audit_watch {
49 atomic_t count; /* reference count */
cfcad62c 50 dev_t dev; /* associated superblock device */
e08b061e 51 char *path; /* insertion path */
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52 unsigned long ino; /* associated inode number */
53 struct audit_parent *parent; /* associated parent */
54 struct list_head wlist; /* entry in parent->watches list */
ae7b8f41 55 struct list_head rules; /* anchor for krule->rlist */
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56};
57
58struct audit_parent {
ae7b8f41 59 struct list_head watches; /* anchor for audit_watch->wlist */
e61ce867 60 struct fsnotify_mark mark; /* fsnotify mark on the inode */
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61};
62
e9fd702a 63/* fsnotify handle. */
b8800aa5 64static struct fsnotify_group *audit_watch_group;
cfcad62c 65
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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)
cfcad62c 69
ae7b8f41
EP
70static void audit_free_parent(struct audit_parent *parent)
71{
72 WARN_ON(!list_empty(&parent->watches));
73 kfree(parent);
74}
75
e61ce867 76static void audit_watch_free_mark(struct fsnotify_mark *entry)
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77{
78 struct audit_parent *parent;
79
e9fd702a 80 parent = container_of(entry, struct audit_parent, mark);
ae7b8f41 81 audit_free_parent(parent);
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82}
83
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84static void audit_get_parent(struct audit_parent *parent)
85{
86 if (likely(parent))
87 fsnotify_get_mark(&parent->mark);
88}
89
90static void audit_put_parent(struct audit_parent *parent)
91{
92 if (likely(parent))
93 fsnotify_put_mark(&parent->mark);
94}
95
96/*
97 * Find and return the audit_parent on the given inode. If found a reference
98 * is taken on this parent.
99 */
100static inline struct audit_parent *audit_find_parent(struct inode *inode)
101{
102 struct audit_parent *parent = NULL;
e61ce867 103 struct fsnotify_mark *entry;
e9fd702a 104
5444e298 105 entry = fsnotify_find_inode_mark(audit_watch_group, inode);
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106 if (entry)
107 parent = container_of(entry, struct audit_parent, mark);
108
109 return parent;
110}
111
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112void audit_get_watch(struct audit_watch *watch)
113{
114 atomic_inc(&watch->count);
115}
116
117void audit_put_watch(struct audit_watch *watch)
118{
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);
124 }
125}
126
b8800aa5 127static void audit_remove_watch(struct audit_watch *watch)
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128{
129 list_del(&watch->wlist);
e9fd702a 130 audit_put_parent(watch->parent);
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131 watch->parent = NULL;
132 audit_put_watch(watch); /* match initial get */
133}
134
135char *audit_watch_path(struct audit_watch *watch)
136{
137 return watch->path;
138}
139
ae7b8f41 140int audit_watch_compare(struct audit_watch *watch, unsigned long ino, dev_t dev)
cfcad62c 141{
84cb777e 142 return (watch->ino != AUDIT_INO_UNSET) &&
ae7b8f41
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143 (watch->ino == ino) &&
144 (watch->dev == dev);
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145}
146
147/* Initialize a parent watch entry. */
15a9155f 148static struct audit_parent *audit_init_parent(struct path *path)
cfcad62c 149{
3b362157 150 struct inode *inode = d_backing_inode(path->dentry);
cfcad62c 151 struct audit_parent *parent;
e9fd702a 152 int ret;
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153
154 parent = kzalloc(sizeof(*parent), GFP_KERNEL);
155 if (unlikely(!parent))
156 return ERR_PTR(-ENOMEM);
157
158 INIT_LIST_HEAD(&parent->watches);
cfcad62c 159
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EP
160 fsnotify_init_mark(&parent->mark, audit_watch_free_mark);
161 parent->mark.mask = AUDIT_FS_WATCH;
5444e298 162 ret = fsnotify_add_mark(&parent->mark, audit_watch_group, inode, NULL, 0);
e9fd702a 163 if (ret < 0) {
ae7b8f41 164 audit_free_parent(parent);
e9fd702a 165 return ERR_PTR(ret);
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166 }
167
168 return parent;
169}
170
171/* Initialize a watch entry. */
172static struct audit_watch *audit_init_watch(char *path)
173{
174 struct audit_watch *watch;
175
176 watch = kzalloc(sizeof(*watch), GFP_KERNEL);
177 if (unlikely(!watch))
178 return ERR_PTR(-ENOMEM);
179
180 INIT_LIST_HEAD(&watch->rules);
181 atomic_set(&watch->count, 1);
182 watch->path = path;
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183 watch->dev = AUDIT_DEV_UNSET;
184 watch->ino = AUDIT_INO_UNSET;
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185
186 return watch;
187}
188
fd97646b 189/* Translate a watch string to kernel representation. */
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190int audit_to_watch(struct audit_krule *krule, char *path, int len, u32 op)
191{
192 struct audit_watch *watch;
193
e9fd702a 194 if (!audit_watch_group)
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195 return -EOPNOTSUPP;
196
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;
202
203 watch = audit_init_watch(path);
204 if (IS_ERR(watch))
205 return PTR_ERR(watch);
206
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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;
e9fd702a 231 audit_get_parent(old->parent);
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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);
0644ec0c
KC
243 if (unlikely(!ab))
244 return;
cfcad62c 245 audit_log_format(ab, "auid=%u ses=%u op=",
e1760bd5 246 from_kuid(&init_user_ns, audit_get_loginuid(current)),
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247 audit_get_sessionid(current));
248 audit_log_string(ab, op);
249 audit_log_format(ab, " path=");
250 audit_log_untrustedstring(ab, w->path);
9d960985 251 audit_log_key(ab, r->filterkey);
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252 audit_log_format(ab, " list=%d res=1", r->listnr);
253 audit_log_end(ab);
254 }
255}
256
257/* Update inode info in audit rules based on filesystem event. */
258static void audit_update_watch(struct audit_parent *parent,
259 const char *dname, dev_t dev,
260 unsigned long ino, unsigned invalidating)
261{
262 struct audit_watch *owatch, *nwatch, *nextw;
263 struct audit_krule *r, *nextr;
264 struct audit_entry *oentry, *nentry;
265
266 mutex_lock(&audit_filter_mutex);
ae7b8f41
EP
267 /* Run all of the watches on this parent looking for the one that
268 * matches the given dname */
cfcad62c 269 list_for_each_entry_safe(owatch, nextw, &parent->watches, wlist) {
e3d6b07b
JL
270 if (audit_compare_dname_path(dname, owatch->path,
271 AUDIT_NAME_FULL))
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272 continue;
273
274 /* If the update involves invalidating rules, do the inode-based
275 * filtering now, so we don't omit records. */
ae7b8f41 276 if (invalidating && !audit_dummy_context())
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277 audit_filter_inodes(current, current->audit_context);
278
ae7b8f41
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279 /* updating ino will likely change which audit_hash_list we
280 * are on so we need a new watch for the new list */
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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;
286 }
287 nwatch->dev = dev;
288 nwatch->ino = ino;
289
290 list_for_each_entry_safe(r, nextr, &owatch->rules, rlist) {
291
292 oentry = container_of(r, struct audit_entry, rule);
293 list_del(&oentry->rule.rlist);
294 list_del_rcu(&oentry->list);
295
ae7b8f41 296 nentry = audit_dupe_rule(&oentry->rule);
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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);
ae7b8f41
EP
302
303 /*
304 * nentry->rule.watch == oentry->rule.watch so
305 * we must drop that reference and set it to our
306 * new watch.
307 */
308 audit_put_watch(nentry->rule.watch);
309 audit_get_watch(nwatch);
310 nentry->rule.watch = nwatch;
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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);
315 }
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316 if (oentry->rule.exe)
317 audit_remove_mark(oentry->rule.exe);
cfcad62c 318
e7df61f4 319 audit_watch_log_rule_change(r, owatch, "updated_rules");
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320
321 call_rcu(&oentry->rcu, audit_free_rule_rcu);
322 }
323
324 audit_remove_watch(owatch);
325 goto add_watch_to_parent; /* event applies to a single watch */
326 }
327 mutex_unlock(&audit_filter_mutex);
328 return;
329
330add_watch_to_parent:
331 list_add(&nwatch->wlist, &parent->watches);
332 mutex_unlock(&audit_filter_mutex);
333 return;
334}
335
336/* Remove all watches & rules associated with a parent that is going away. */
337static void audit_remove_parent_watches(struct audit_parent *parent)
338{
339 struct audit_watch *w, *nextw;
340 struct audit_krule *r, *nextr;
341 struct audit_entry *e;
342
343 mutex_lock(&audit_filter_mutex);
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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);
e7df61f4 347 audit_watch_log_rule_change(r, w, "remove_rule");
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348 if (e->rule.exe)
349 audit_remove_mark(e->rule.exe);
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EP
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);
354 }
355 audit_remove_watch(w);
356 }
357 mutex_unlock(&audit_filter_mutex);
e9fd702a 358
e2a29943 359 fsnotify_destroy_mark(&parent->mark, audit_watch_group);
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360}
361
cfcad62c 362/* Get path information necessary for adding watches. */
15a9155f 363static int audit_get_nd(struct audit_watch *watch, struct path *parent)
cfcad62c 364{
79714f72
AV
365 struct dentry *d = kern_path_locked(watch->path, parent);
366 if (IS_ERR(d))
15a9155f 367 return PTR_ERR(d);
5955102c 368 inode_unlock(d_backing_inode(parent->dentry));
3b362157 369 if (d_is_positive(d)) {
15a9155f 370 /* update watch filter fields */
fc64005c 371 watch->dev = d->d_sb->s_dev;
3b362157 372 watch->ino = d_backing_inode(d)->i_ino;
cfcad62c 373 }
15a9155f 374 dput(d);
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EP
375 return 0;
376}
377
e9fd702a 378/* Associate the given rule with an existing parent.
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EP
379 * Caller must hold audit_filter_mutex. */
380static void audit_add_to_parent(struct audit_krule *krule,
381 struct audit_parent *parent)
382{
383 struct audit_watch *w, *watch = krule->watch;
384 int watch_found = 0;
385
e9fd702a
EP
386 BUG_ON(!mutex_is_locked(&audit_filter_mutex));
387
cfcad62c
EP
388 list_for_each_entry(w, &parent->watches, wlist) {
389 if (strcmp(watch->path, w->path))
390 continue;
391
392 watch_found = 1;
393
f8259b26 394 /* put krule's ref to temporary watch */
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EP
395 audit_put_watch(watch);
396
397 audit_get_watch(w);
398 krule->watch = watch = w;
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RGB
399
400 audit_put_parent(parent);
cfcad62c
EP
401 break;
402 }
403
404 if (!watch_found) {
cfcad62c
EP
405 watch->parent = parent;
406
f8259b26 407 audit_get_watch(watch);
cfcad62c
EP
408 list_add(&watch->wlist, &parent->watches);
409 }
410 list_add(&krule->rlist, &watch->rules);
411}
412
413/* Find a matching watch entry, or add this one.
414 * Caller must hold audit_filter_mutex. */
ae7b8f41 415int audit_add_watch(struct audit_krule *krule, struct list_head **list)
cfcad62c
EP
416{
417 struct audit_watch *watch = krule->watch;
cfcad62c 418 struct audit_parent *parent;
15a9155f 419 struct path parent_path;
ae7b8f41 420 int h, ret = 0;
cfcad62c 421
35fe4d0b
EP
422 mutex_unlock(&audit_filter_mutex);
423
424 /* Avoid calling path_lookup under audit_filter_mutex. */
15a9155f 425 ret = audit_get_nd(watch, &parent_path);
35fe4d0b 426
15a9155f 427 /* caller expects mutex locked */
e118e9c5
EP
428 mutex_lock(&audit_filter_mutex);
429
15a9155f
AV
430 if (ret)
431 return ret;
cfcad62c 432
e118e9c5 433 /* either find an old parent or attach a new one */
3b362157 434 parent = audit_find_parent(d_backing_inode(parent_path.dentry));
e9fd702a 435 if (!parent) {
15a9155f 436 parent = audit_init_parent(&parent_path);
cfcad62c 437 if (IS_ERR(parent)) {
35fe4d0b
EP
438 ret = PTR_ERR(parent);
439 goto error;
cfcad62c 440 }
e9fd702a 441 }
cfcad62c 442
e118e9c5 443 audit_add_to_parent(krule, parent);
cfcad62c 444
ae7b8f41
EP
445 h = audit_hash_ino((u32)watch->ino);
446 *list = &audit_inode_hash[h];
35fe4d0b 447error:
15a9155f 448 path_put(&parent_path);
cfcad62c
EP
449 return ret;
450}
451
a05fb6cc 452void audit_remove_watch_rule(struct audit_krule *krule)
cfcad62c
EP
453{
454 struct audit_watch *watch = krule->watch;
455 struct audit_parent *parent = watch->parent;
456
457 list_del(&krule->rlist);
458
459 if (list_empty(&watch->rules)) {
460 audit_remove_watch(watch);
461
462 if (list_empty(&parent->watches)) {
e9fd702a 463 audit_get_parent(parent);
e2a29943 464 fsnotify_destroy_mark(&parent->mark, audit_watch_group);
a05fb6cc 465 audit_put_parent(parent);
cfcad62c
EP
466 }
467 }
468}
469
e9fd702a 470/* Update watch data in audit rules based on fsnotify events. */
3a9b16b4 471static int audit_watch_handle_event(struct fsnotify_group *group,
7053aee2 472 struct inode *to_tell,
ce8f76fb
EP
473 struct fsnotify_mark *inode_mark,
474 struct fsnotify_mark *vfsmount_mark,
7053aee2 475 u32 mask, void *data, int data_type,
45a22f4c 476 const unsigned char *dname, u32 cookie)
e9fd702a
EP
477{
478 struct inode *inode;
cfcad62c
EP
479 struct audit_parent *parent;
480
ce8f76fb 481 parent = container_of(inode_mark, struct audit_parent, mark);
e9fd702a 482
4cd76a47 483 BUG_ON(group != audit_watch_group);
e9fd702a 484
7053aee2 485 switch (data_type) {
2069601b 486 case (FSNOTIFY_EVENT_PATH):
3b362157 487 inode = d_backing_inode(((struct path *)data)->dentry);
e9fd702a
EP
488 break;
489 case (FSNOTIFY_EVENT_INODE):
7053aee2 490 inode = (struct inode *)data;
e9fd702a
EP
491 break;
492 default:
493 BUG();
494 inode = NULL;
495 break;
496 };
cfcad62c 497
e9fd702a 498 if (mask & (FS_CREATE|FS_MOVED_TO) && inode)
ae7b8f41 499 audit_update_watch(parent, dname, inode->i_sb->s_dev, inode->i_ino, 0);
e9fd702a 500 else if (mask & (FS_DELETE|FS_MOVED_FROM))
84cb777e 501 audit_update_watch(parent, dname, AUDIT_DEV_UNSET, AUDIT_INO_UNSET, 1);
e9fd702a 502 else if (mask & (FS_DELETE_SELF|FS_UNMOUNT|FS_MOVE_SELF))
cfcad62c 503 audit_remove_parent_watches(parent);
e9fd702a
EP
504
505 return 0;
506}
507
e9fd702a 508static const struct fsnotify_ops audit_watch_fsnotify_ops = {
e9fd702a 509 .handle_event = audit_watch_handle_event,
cfcad62c
EP
510};
511
512static int __init audit_watch_init(void)
513{
0d2e2a1d 514 audit_watch_group = fsnotify_alloc_group(&audit_watch_fsnotify_ops);
e9fd702a
EP
515 if (IS_ERR(audit_watch_group)) {
516 audit_watch_group = NULL;
517 audit_panic("cannot create audit fsnotify group");
518 }
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EP
519 return 0;
520}
1a3aedbc 521device_initcall(audit_watch_init);
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522
523int audit_dupe_exe(struct audit_krule *new, struct audit_krule *old)
524{
525 struct audit_fsnotify_mark *audit_mark;
526 char *pathname;
527
528 pathname = kstrdup(audit_mark_path(old->exe), GFP_KERNEL);
529 if (!pathname)
530 return -ENOMEM;
531
532 audit_mark = audit_alloc_mark(new, pathname, strlen(pathname));
533 if (IS_ERR(audit_mark)) {
534 kfree(pathname);
535 return PTR_ERR(audit_mark);
536 }
537 new->exe = audit_mark;
538
539 return 0;
540}
541
542int audit_exe_compare(struct task_struct *tsk, struct audit_fsnotify_mark *mark)
543{
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544 struct file *exe_file;
545 unsigned long ino;
546 dev_t dev;
547
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548 exe_file = get_task_exe_file(tsk);
549 if (!exe_file)
550 return 0;
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551 ino = exe_file->f_inode->i_ino;
552 dev = exe_file->f_inode->i_sb->s_dev;
5efc2443 553 fput(exe_file);
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554 return audit_mark_compare(mark, ino, dev);
555}
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