blob: 063224812b7e607879bffeedd5b90f9c4967346f [file] [log] [blame]
Andreas Gruenbacher33d3dff2009-12-17 21:24:29 -05001#include <linux/fanotify.h>
Eric Paris11637e42009-12-17 21:24:25 -05002#include <linux/fcntl.h>
Eric Paris2a3edf82009-12-17 21:24:26 -05003#include <linux/file.h>
Eric Paris11637e42009-12-17 21:24:25 -05004#include <linux/fs.h>
Eric Paris52c923d2009-12-17 21:24:26 -05005#include <linux/anon_inodes.h>
Eric Paris11637e42009-12-17 21:24:25 -05006#include <linux/fsnotify_backend.h>
Eric Paris2a3edf82009-12-17 21:24:26 -05007#include <linux/init.h>
Eric Parisa1014f12009-12-17 21:24:26 -05008#include <linux/mount.h>
Eric Paris2a3edf82009-12-17 21:24:26 -05009#include <linux/namei.h>
Eric Parisa1014f12009-12-17 21:24:26 -050010#include <linux/poll.h>
Eric Paris11637e42009-12-17 21:24:25 -050011#include <linux/security.h>
12#include <linux/syscalls.h>
Tejun Heoe4e047a2010-05-20 01:36:28 +100013#include <linux/slab.h>
Eric Paris2a3edf82009-12-17 21:24:26 -050014#include <linux/types.h>
Eric Parisa1014f12009-12-17 21:24:26 -050015#include <linux/uaccess.h>
16
17#include <asm/ioctls.h>
Eric Paris11637e42009-12-17 21:24:25 -050018
Eric Paris2529a0d2010-10-28 17:21:57 -040019#define FANOTIFY_DEFAULT_MAX_EVENTS 16384
Eric Parise7099d82010-10-28 17:21:57 -040020#define FANOTIFY_DEFAULT_MAX_MARKS 8192
Eric Paris4afeff82010-10-28 17:21:58 -040021#define FANOTIFY_DEFAULT_MAX_LISTENERS 128
Eric Paris2529a0d2010-10-28 17:21:57 -040022
Andreas Gruenbacher33d3dff2009-12-17 21:24:29 -050023extern const struct fsnotify_ops fanotify_fsnotify_ops;
Eric Paris11637e42009-12-17 21:24:25 -050024
Eric Paris2a3edf82009-12-17 21:24:26 -050025static struct kmem_cache *fanotify_mark_cache __read_mostly;
Eric Parisb2d87902009-12-17 21:24:34 -050026static struct kmem_cache *fanotify_response_event_cache __read_mostly;
27
28struct fanotify_response_event {
29 struct list_head list;
30 __s32 fd;
31 struct fsnotify_event *event;
32};
Eric Paris2a3edf82009-12-17 21:24:26 -050033
Eric Parisa1014f12009-12-17 21:24:26 -050034/*
35 * Get an fsnotify notification event if one exists and is small
36 * enough to fit in "count". Return an error pointer if the count
37 * is not large enough.
38 *
39 * Called with the group->notification_mutex held.
40 */
41static struct fsnotify_event *get_one_event(struct fsnotify_group *group,
42 size_t count)
43{
44 BUG_ON(!mutex_is_locked(&group->notification_mutex));
45
46 pr_debug("%s: group=%p count=%zd\n", __func__, group, count);
47
48 if (fsnotify_notify_queue_is_empty(group))
49 return NULL;
50
51 if (FAN_EVENT_METADATA_LEN > count)
52 return ERR_PTR(-EINVAL);
53
54 /* held the notification_mutex the whole time, so this is the
55 * same event we peeked above */
56 return fsnotify_remove_notify_event(group);
57}
58
Andreas Gruenbacher22aa4252009-12-17 21:24:26 -050059static int create_fd(struct fsnotify_group *group, struct fsnotify_event *event)
Eric Parisa1014f12009-12-17 21:24:26 -050060{
61 int client_fd;
62 struct dentry *dentry;
63 struct vfsmount *mnt;
64 struct file *new_file;
65
Andreas Gruenbacher22aa4252009-12-17 21:24:26 -050066 pr_debug("%s: group=%p event=%p\n", __func__, group, event);
Eric Parisa1014f12009-12-17 21:24:26 -050067
68 client_fd = get_unused_fd();
69 if (client_fd < 0)
70 return client_fd;
71
Linus Torvalds20696012010-08-12 14:23:04 -070072 if (event->data_type != FSNOTIFY_EVENT_PATH) {
Eric Parisa1014f12009-12-17 21:24:26 -050073 WARN_ON(1);
74 put_unused_fd(client_fd);
75 return -EINVAL;
76 }
77
78 /*
79 * we need a new file handle for the userspace program so it can read even if it was
80 * originally opened O_WRONLY.
81 */
Linus Torvalds20696012010-08-12 14:23:04 -070082 dentry = dget(event->path.dentry);
83 mnt = mntget(event->path.mnt);
Eric Parisa1014f12009-12-17 21:24:26 -050084 /* it's possible this event was an overflow event. in that case dentry and mnt
85 * are NULL; That's fine, just don't call dentry open */
86 if (dentry && mnt)
87 new_file = dentry_open(dentry, mnt,
Eric Paris80af2582010-07-28 10:18:37 -040088 group->fanotify_data.f_flags | FMODE_NONOTIFY,
Eric Parisa1014f12009-12-17 21:24:26 -050089 current_cred());
90 else
91 new_file = ERR_PTR(-EOVERFLOW);
92 if (IS_ERR(new_file)) {
93 /*
94 * we still send an event even if we can't open the file. this
95 * can happen when say tasks are gone and we try to open their
96 * /proc files or we try to open a WRONLY file like in sysfs
97 * we just send the errno to userspace since there isn't much
98 * else we can do.
99 */
100 put_unused_fd(client_fd);
101 client_fd = PTR_ERR(new_file);
102 } else {
103 fd_install(client_fd, new_file);
104 }
105
Andreas Gruenbacher22aa4252009-12-17 21:24:26 -0500106 return client_fd;
Eric Parisa1014f12009-12-17 21:24:26 -0500107}
108
109static ssize_t fill_event_metadata(struct fsnotify_group *group,
110 struct fanotify_event_metadata *metadata,
111 struct fsnotify_event *event)
112{
113 pr_debug("%s: group=%p metadata=%p event=%p\n", __func__,
114 group, metadata, event);
115
116 metadata->event_len = FAN_EVENT_METADATA_LEN;
117 metadata->vers = FANOTIFY_METADATA_VERSION;
Andreas Gruenbacher33d3dff2009-12-17 21:24:29 -0500118 metadata->mask = event->mask & FAN_ALL_OUTGOING_EVENTS;
Andreas Gruenbacher32c32632009-12-17 21:24:27 -0500119 metadata->pid = pid_vnr(event->tgid);
Andreas Gruenbacher22aa4252009-12-17 21:24:26 -0500120 metadata->fd = create_fd(group, event);
Eric Parisa1014f12009-12-17 21:24:26 -0500121
Andreas Gruenbacher22aa4252009-12-17 21:24:26 -0500122 return metadata->fd;
Eric Parisa1014f12009-12-17 21:24:26 -0500123}
124
Eric Parisb2d87902009-12-17 21:24:34 -0500125#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
126static struct fanotify_response_event *dequeue_re(struct fsnotify_group *group,
127 __s32 fd)
128{
129 struct fanotify_response_event *re, *return_re = NULL;
130
131 mutex_lock(&group->fanotify_data.access_mutex);
132 list_for_each_entry(re, &group->fanotify_data.access_list, list) {
133 if (re->fd != fd)
134 continue;
135
136 list_del_init(&re->list);
137 return_re = re;
138 break;
139 }
140 mutex_unlock(&group->fanotify_data.access_mutex);
141
142 pr_debug("%s: found return_re=%p\n", __func__, return_re);
143
144 return return_re;
145}
146
147static int process_access_response(struct fsnotify_group *group,
148 struct fanotify_response *response_struct)
149{
150 struct fanotify_response_event *re;
151 __s32 fd = response_struct->fd;
152 __u32 response = response_struct->response;
153
154 pr_debug("%s: group=%p fd=%d response=%d\n", __func__, group,
155 fd, response);
156 /*
157 * make sure the response is valid, if invalid we do nothing and either
158 * userspace can send a valid responce or we will clean it up after the
159 * timeout
160 */
161 switch (response) {
162 case FAN_ALLOW:
163 case FAN_DENY:
164 break;
165 default:
166 return -EINVAL;
167 }
168
169 if (fd < 0)
170 return -EINVAL;
171
172 re = dequeue_re(group, fd);
173 if (!re)
174 return -ENOENT;
175
176 re->event->response = response;
177
178 wake_up(&group->fanotify_data.access_waitq);
179
180 kmem_cache_free(fanotify_response_event_cache, re);
181
182 return 0;
183}
184
185static int prepare_for_access_response(struct fsnotify_group *group,
186 struct fsnotify_event *event,
187 __s32 fd)
188{
189 struct fanotify_response_event *re;
190
191 if (!(event->mask & FAN_ALL_PERM_EVENTS))
192 return 0;
193
194 re = kmem_cache_alloc(fanotify_response_event_cache, GFP_KERNEL);
195 if (!re)
196 return -ENOMEM;
197
198 re->event = event;
199 re->fd = fd;
200
201 mutex_lock(&group->fanotify_data.access_mutex);
Eric Paris2eebf582010-08-18 12:25:50 -0400202
203 if (group->fanotify_data.bypass_perm) {
204 mutex_unlock(&group->fanotify_data.access_mutex);
205 kmem_cache_free(fanotify_response_event_cache, re);
206 event->response = FAN_ALLOW;
207 return 0;
208 }
209
Eric Parisb2d87902009-12-17 21:24:34 -0500210 list_add_tail(&re->list, &group->fanotify_data.access_list);
211 mutex_unlock(&group->fanotify_data.access_mutex);
212
213 return 0;
214}
215
216static void remove_access_response(struct fsnotify_group *group,
217 struct fsnotify_event *event,
218 __s32 fd)
219{
220 struct fanotify_response_event *re;
221
222 if (!(event->mask & FAN_ALL_PERM_EVENTS))
223 return;
224
225 re = dequeue_re(group, fd);
226 if (!re)
227 return;
228
229 BUG_ON(re->event != event);
230
231 kmem_cache_free(fanotify_response_event_cache, re);
232
233 return;
234}
235#else
236static int prepare_for_access_response(struct fsnotify_group *group,
237 struct fsnotify_event *event,
238 __s32 fd)
239{
240 return 0;
241}
242
243static void remove_access_response(struct fsnotify_group *group,
244 struct fsnotify_event *event,
245 __s32 fd)
246{
Eric Paris8860f062009-12-23 00:10:25 -0500247 return;
Eric Parisb2d87902009-12-17 21:24:34 -0500248}
249#endif
250
Eric Parisa1014f12009-12-17 21:24:26 -0500251static ssize_t copy_event_to_user(struct fsnotify_group *group,
252 struct fsnotify_event *event,
253 char __user *buf)
254{
255 struct fanotify_event_metadata fanotify_event_metadata;
Eric Parisb2d87902009-12-17 21:24:34 -0500256 int fd, ret;
Eric Parisa1014f12009-12-17 21:24:26 -0500257
258 pr_debug("%s: group=%p event=%p\n", __func__, group, event);
259
Eric Parisb2d87902009-12-17 21:24:34 -0500260 fd = fill_event_metadata(group, &fanotify_event_metadata, event);
261 if (fd < 0)
262 return fd;
Eric Parisa1014f12009-12-17 21:24:26 -0500263
Eric Parisb2d87902009-12-17 21:24:34 -0500264 ret = prepare_for_access_response(group, event, fd);
265 if (ret)
266 goto out_close_fd;
267
268 ret = -EFAULT;
Eric Parisa1014f12009-12-17 21:24:26 -0500269 if (copy_to_user(buf, &fanotify_event_metadata, FAN_EVENT_METADATA_LEN))
Eric Parisb2d87902009-12-17 21:24:34 -0500270 goto out_kill_access_response;
Eric Parisa1014f12009-12-17 21:24:26 -0500271
272 return FAN_EVENT_METADATA_LEN;
Eric Parisb2d87902009-12-17 21:24:34 -0500273
274out_kill_access_response:
275 remove_access_response(group, event, fd);
276out_close_fd:
277 sys_close(fd);
278 return ret;
Eric Parisa1014f12009-12-17 21:24:26 -0500279}
280
281/* intofiy userspace file descriptor functions */
282static unsigned int fanotify_poll(struct file *file, poll_table *wait)
283{
284 struct fsnotify_group *group = file->private_data;
285 int ret = 0;
286
287 poll_wait(file, &group->notification_waitq, wait);
288 mutex_lock(&group->notification_mutex);
289 if (!fsnotify_notify_queue_is_empty(group))
290 ret = POLLIN | POLLRDNORM;
291 mutex_unlock(&group->notification_mutex);
292
293 return ret;
294}
295
296static ssize_t fanotify_read(struct file *file, char __user *buf,
297 size_t count, loff_t *pos)
298{
299 struct fsnotify_group *group;
300 struct fsnotify_event *kevent;
301 char __user *start;
302 int ret;
303 DEFINE_WAIT(wait);
304
305 start = buf;
306 group = file->private_data;
307
308 pr_debug("%s: group=%p\n", __func__, group);
309
310 while (1) {
311 prepare_to_wait(&group->notification_waitq, &wait, TASK_INTERRUPTIBLE);
312
313 mutex_lock(&group->notification_mutex);
314 kevent = get_one_event(group, count);
315 mutex_unlock(&group->notification_mutex);
316
317 if (kevent) {
318 ret = PTR_ERR(kevent);
319 if (IS_ERR(kevent))
320 break;
321 ret = copy_event_to_user(group, kevent, buf);
322 fsnotify_put_event(kevent);
323 if (ret < 0)
324 break;
325 buf += ret;
326 count -= ret;
327 continue;
328 }
329
330 ret = -EAGAIN;
331 if (file->f_flags & O_NONBLOCK)
332 break;
Lino Sanfilippo1a5cea72010-10-29 12:06:42 +0200333 ret = -ERESTARTSYS;
Eric Parisa1014f12009-12-17 21:24:26 -0500334 if (signal_pending(current))
335 break;
336
337 if (start != buf)
338 break;
339
340 schedule();
341 }
342
343 finish_wait(&group->notification_waitq, &wait);
344 if (start != buf && ret != -EFAULT)
345 ret = buf - start;
346 return ret;
347}
348
Eric Parisb2d87902009-12-17 21:24:34 -0500349static ssize_t fanotify_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)
350{
351#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
352 struct fanotify_response response = { .fd = -1, .response = -1 };
353 struct fsnotify_group *group;
354 int ret;
355
356 group = file->private_data;
357
358 if (count > sizeof(response))
359 count = sizeof(response);
360
361 pr_debug("%s: group=%p count=%zu\n", __func__, group, count);
362
363 if (copy_from_user(&response, buf, count))
364 return -EFAULT;
365
366 ret = process_access_response(group, &response);
367 if (ret < 0)
368 count = ret;
369
370 return count;
371#else
372 return -EINVAL;
373#endif
374}
375
Eric Paris52c923d2009-12-17 21:24:26 -0500376static int fanotify_release(struct inode *ignored, struct file *file)
377{
378 struct fsnotify_group *group = file->private_data;
Eric Paris52c923d2009-12-17 21:24:26 -0500379
Eric Paris2eebf582010-08-18 12:25:50 -0400380#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
Andrew Morton19ba54f2010-10-28 17:21:59 -0400381 struct fanotify_response_event *re, *lre;
382
Eric Paris2eebf582010-08-18 12:25:50 -0400383 mutex_lock(&group->fanotify_data.access_mutex);
384
385 group->fanotify_data.bypass_perm = true;
386
387 list_for_each_entry_safe(re, lre, &group->fanotify_data.access_list, list) {
388 pr_debug("%s: found group=%p re=%p event=%p\n", __func__, group,
389 re, re->event);
390
391 list_del_init(&re->list);
392 re->event->response = FAN_ALLOW;
393
394 kmem_cache_free(fanotify_response_event_cache, re);
395 }
396 mutex_unlock(&group->fanotify_data.access_mutex);
397
398 wake_up(&group->fanotify_data.access_waitq);
399#endif
Eric Paris52c923d2009-12-17 21:24:26 -0500400 /* matches the fanotify_init->fsnotify_alloc_group */
401 fsnotify_put_group(group);
402
403 return 0;
404}
405
Eric Parisa1014f12009-12-17 21:24:26 -0500406static long fanotify_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
407{
408 struct fsnotify_group *group;
409 struct fsnotify_event_holder *holder;
410 void __user *p;
411 int ret = -ENOTTY;
412 size_t send_len = 0;
413
414 group = file->private_data;
415
416 p = (void __user *) arg;
417
418 switch (cmd) {
419 case FIONREAD:
420 mutex_lock(&group->notification_mutex);
421 list_for_each_entry(holder, &group->notification_list, event_list)
422 send_len += FAN_EVENT_METADATA_LEN;
423 mutex_unlock(&group->notification_mutex);
424 ret = put_user(send_len, (int __user *) p);
425 break;
426 }
427
428 return ret;
429}
430
Eric Paris52c923d2009-12-17 21:24:26 -0500431static const struct file_operations fanotify_fops = {
Eric Parisa1014f12009-12-17 21:24:26 -0500432 .poll = fanotify_poll,
433 .read = fanotify_read,
Eric Parisb2d87902009-12-17 21:24:34 -0500434 .write = fanotify_write,
Eric Paris52c923d2009-12-17 21:24:26 -0500435 .fasync = NULL,
436 .release = fanotify_release,
Eric Parisa1014f12009-12-17 21:24:26 -0500437 .unlocked_ioctl = fanotify_ioctl,
438 .compat_ioctl = fanotify_ioctl,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200439 .llseek = noop_llseek,
Eric Paris52c923d2009-12-17 21:24:26 -0500440};
441
Eric Paris2a3edf82009-12-17 21:24:26 -0500442static void fanotify_free_mark(struct fsnotify_mark *fsn_mark)
443{
444 kmem_cache_free(fanotify_mark_cache, fsn_mark);
445}
446
447static int fanotify_find_path(int dfd, const char __user *filename,
448 struct path *path, unsigned int flags)
449{
450 int ret;
451
452 pr_debug("%s: dfd=%d filename=%p flags=%x\n", __func__,
453 dfd, filename, flags);
454
455 if (filename == NULL) {
456 struct file *file;
457 int fput_needed;
458
459 ret = -EBADF;
460 file = fget_light(dfd, &fput_needed);
461 if (!file)
462 goto out;
463
464 ret = -ENOTDIR;
465 if ((flags & FAN_MARK_ONLYDIR) &&
466 !(S_ISDIR(file->f_path.dentry->d_inode->i_mode))) {
467 fput_light(file, fput_needed);
468 goto out;
469 }
470
471 *path = file->f_path;
472 path_get(path);
473 fput_light(file, fput_needed);
474 } else {
475 unsigned int lookup_flags = 0;
476
477 if (!(flags & FAN_MARK_DONT_FOLLOW))
478 lookup_flags |= LOOKUP_FOLLOW;
479 if (flags & FAN_MARK_ONLYDIR)
480 lookup_flags |= LOOKUP_DIRECTORY;
481
482 ret = user_path_at(dfd, filename, lookup_flags, path);
483 if (ret)
484 goto out;
485 }
486
487 /* you can only watch an inode if you have read permissions on it */
488 ret = inode_permission(path->dentry->d_inode, MAY_READ);
489 if (ret)
490 path_put(path);
491out:
492 return ret;
493}
494
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500495static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark,
496 __u32 mask,
497 unsigned int flags)
Andreas Gruenbacher088b09b2009-12-17 21:24:28 -0500498{
499 __u32 oldmask;
500
501 spin_lock(&fsn_mark->lock);
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500502 if (!(flags & FAN_MARK_IGNORED_MASK)) {
503 oldmask = fsn_mark->mask;
504 fsnotify_set_mark_mask_locked(fsn_mark, (oldmask & ~mask));
505 } else {
506 oldmask = fsn_mark->ignored_mask;
507 fsnotify_set_mark_ignored_mask_locked(fsn_mark, (oldmask & ~mask));
508 }
Andreas Gruenbacher088b09b2009-12-17 21:24:28 -0500509 spin_unlock(&fsn_mark->lock);
510
511 if (!(oldmask & ~mask))
512 fsnotify_destroy_mark(fsn_mark);
513
514 return mask & oldmask;
515}
516
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500517static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group,
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500518 struct vfsmount *mnt, __u32 mask,
519 unsigned int flags)
Eric Paris88826272009-12-17 21:24:28 -0500520{
521 struct fsnotify_mark *fsn_mark = NULL;
Andreas Gruenbacher088b09b2009-12-17 21:24:28 -0500522 __u32 removed;
Eric Paris88826272009-12-17 21:24:28 -0500523
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500524 fsn_mark = fsnotify_find_vfsmount_mark(group, mnt);
525 if (!fsn_mark)
526 return -ENOENT;
Eric Paris88826272009-12-17 21:24:28 -0500527
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500528 removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags);
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500529 fsnotify_put_mark(fsn_mark);
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500530 if (removed & mnt->mnt_fsnotify_mask)
531 fsnotify_recalc_vfsmount_mask(mnt);
Eric Paris88826272009-12-17 21:24:28 -0500532
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500533 return 0;
534}
535
536static int fanotify_remove_inode_mark(struct fsnotify_group *group,
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500537 struct inode *inode, __u32 mask,
538 unsigned int flags)
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500539{
540 struct fsnotify_mark *fsn_mark = NULL;
541 __u32 removed;
542
543 fsn_mark = fsnotify_find_inode_mark(group, inode);
Eric Paris88826272009-12-17 21:24:28 -0500544 if (!fsn_mark)
545 return -ENOENT;
546
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500547 removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags);
Eric Paris5444e292009-12-17 21:24:27 -0500548 /* matches the fsnotify_find_inode_mark() */
Eric Paris2a3edf82009-12-17 21:24:26 -0500549 fsnotify_put_mark(fsn_mark);
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500550 if (removed & inode->i_fsnotify_mask)
551 fsnotify_recalc_inode_mask(inode);
Andreas Gruenbacher088b09b2009-12-17 21:24:28 -0500552
Eric Paris2a3edf82009-12-17 21:24:26 -0500553 return 0;
554}
555
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500556static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark,
557 __u32 mask,
558 unsigned int flags)
Andreas Gruenbacher912ee39462009-12-17 21:24:28 -0500559{
Eric Paris192ca4d2010-10-28 17:21:59 -0400560 __u32 oldmask = -1;
Andreas Gruenbacher912ee39462009-12-17 21:24:28 -0500561
562 spin_lock(&fsn_mark->lock);
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500563 if (!(flags & FAN_MARK_IGNORED_MASK)) {
564 oldmask = fsn_mark->mask;
565 fsnotify_set_mark_mask_locked(fsn_mark, (oldmask | mask));
566 } else {
Eric Paris192ca4d2010-10-28 17:21:59 -0400567 __u32 tmask = fsn_mark->ignored_mask | mask;
568 fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask);
Eric Parisc9778a92009-12-17 21:24:33 -0500569 if (flags & FAN_MARK_IGNORED_SURV_MODIFY)
570 fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY;
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500571 }
Eric Paris8fcd6522010-10-28 17:21:59 -0400572
573 if (!(flags & FAN_MARK_ONDIR)) {
574 __u32 tmask = fsn_mark->ignored_mask | FAN_ONDIR;
575 fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask);
576 }
577
Andreas Gruenbacher912ee39462009-12-17 21:24:28 -0500578 spin_unlock(&fsn_mark->lock);
579
580 return mask & ~oldmask;
581}
582
Andreas Gruenbacher52202df2009-12-17 21:24:28 -0500583static int fanotify_add_vfsmount_mark(struct fsnotify_group *group,
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500584 struct vfsmount *mnt, __u32 mask,
585 unsigned int flags)
Eric Paris2a3edf82009-12-17 21:24:26 -0500586{
587 struct fsnotify_mark *fsn_mark;
Andreas Gruenbacher912ee39462009-12-17 21:24:28 -0500588 __u32 added;
Eric Paris2a3edf82009-12-17 21:24:26 -0500589
Eric Paris88826272009-12-17 21:24:28 -0500590 fsn_mark = fsnotify_find_vfsmount_mark(group, mnt);
591 if (!fsn_mark) {
Eric Paris88826272009-12-17 21:24:28 -0500592 int ret;
593
Eric Parise7099d82010-10-28 17:21:57 -0400594 if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks)
595 return -ENOSPC;
596
Andreas Gruenbacher912ee39462009-12-17 21:24:28 -0500597 fsn_mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL);
598 if (!fsn_mark)
Andreas Gruenbacher52202df2009-12-17 21:24:28 -0500599 return -ENOMEM;
Eric Paris88826272009-12-17 21:24:28 -0500600
Andreas Gruenbacher912ee39462009-12-17 21:24:28 -0500601 fsnotify_init_mark(fsn_mark, fanotify_free_mark);
602 ret = fsnotify_add_mark(fsn_mark, group, NULL, mnt, 0);
Eric Paris88826272009-12-17 21:24:28 -0500603 if (ret) {
Andreas Gruenbacher912ee39462009-12-17 21:24:28 -0500604 fanotify_free_mark(fsn_mark);
Andreas Gruenbacher52202df2009-12-17 21:24:28 -0500605 return ret;
Eric Paris88826272009-12-17 21:24:28 -0500606 }
Eric Paris88826272009-12-17 21:24:28 -0500607 }
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500608 added = fanotify_mark_add_to_mask(fsn_mark, mask, flags);
Andreas Gruenbacher52202df2009-12-17 21:24:28 -0500609 fsnotify_put_mark(fsn_mark);
Eric Paris43709a22010-07-28 10:18:39 -0400610 if (added & ~mnt->mnt_fsnotify_mask)
611 fsnotify_recalc_vfsmount_mask(mnt);
612
Andreas Gruenbacher52202df2009-12-17 21:24:28 -0500613 return 0;
Eric Paris88826272009-12-17 21:24:28 -0500614}
615
Andreas Gruenbacher52202df2009-12-17 21:24:28 -0500616static int fanotify_add_inode_mark(struct fsnotify_group *group,
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500617 struct inode *inode, __u32 mask,
618 unsigned int flags)
Eric Paris88826272009-12-17 21:24:28 -0500619{
620 struct fsnotify_mark *fsn_mark;
Andreas Gruenbacher912ee39462009-12-17 21:24:28 -0500621 __u32 added;
Eric Paris88826272009-12-17 21:24:28 -0500622
623 pr_debug("%s: group=%p inode=%p\n", __func__, group, inode);
Eric Paris2a3edf82009-12-17 21:24:26 -0500624
Eric Paris5322a592010-10-28 17:21:57 -0400625 /*
626 * If some other task has this inode open for write we should not add
627 * an ignored mark, unless that ignored mark is supposed to survive
628 * modification changes anyway.
629 */
630 if ((flags & FAN_MARK_IGNORED_MASK) &&
631 !(flags & FAN_MARK_IGNORED_SURV_MODIFY) &&
632 (atomic_read(&inode->i_writecount) > 0))
633 return 0;
634
Eric Paris5444e292009-12-17 21:24:27 -0500635 fsn_mark = fsnotify_find_inode_mark(group, inode);
Eric Paris2a3edf82009-12-17 21:24:26 -0500636 if (!fsn_mark) {
Eric Paris88826272009-12-17 21:24:28 -0500637 int ret;
Eric Paris2a3edf82009-12-17 21:24:26 -0500638
Eric Parise7099d82010-10-28 17:21:57 -0400639 if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks)
640 return -ENOSPC;
641
Andreas Gruenbacher912ee39462009-12-17 21:24:28 -0500642 fsn_mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL);
643 if (!fsn_mark)
Andreas Gruenbacher52202df2009-12-17 21:24:28 -0500644 return -ENOMEM;
Eric Paris2a3edf82009-12-17 21:24:26 -0500645
Andreas Gruenbacher912ee39462009-12-17 21:24:28 -0500646 fsnotify_init_mark(fsn_mark, fanotify_free_mark);
647 ret = fsnotify_add_mark(fsn_mark, group, inode, NULL, 0);
Eric Paris2a3edf82009-12-17 21:24:26 -0500648 if (ret) {
Andreas Gruenbacher912ee39462009-12-17 21:24:28 -0500649 fanotify_free_mark(fsn_mark);
Andreas Gruenbacher52202df2009-12-17 21:24:28 -0500650 return ret;
Eric Paris2a3edf82009-12-17 21:24:26 -0500651 }
Eric Paris2a3edf82009-12-17 21:24:26 -0500652 }
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500653 added = fanotify_mark_add_to_mask(fsn_mark, mask, flags);
Andreas Gruenbacher52202df2009-12-17 21:24:28 -0500654 fsnotify_put_mark(fsn_mark);
Eric Paris43709a22010-07-28 10:18:39 -0400655 if (added & ~inode->i_fsnotify_mask)
656 fsnotify_recalc_inode_mask(inode);
Andreas Gruenbacher52202df2009-12-17 21:24:28 -0500657 return 0;
Eric Paris88826272009-12-17 21:24:28 -0500658}
Eric Paris2a3edf82009-12-17 21:24:26 -0500659
Eric Paris52c923d2009-12-17 21:24:26 -0500660/* fanotify syscalls */
Eric Paris08ae8932010-05-27 09:41:40 -0400661SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
Eric Paris11637e42009-12-17 21:24:25 -0500662{
Eric Paris52c923d2009-12-17 21:24:26 -0500663 struct fsnotify_group *group;
664 int f_flags, fd;
Eric Paris4afeff82010-10-28 17:21:58 -0400665 struct user_struct *user;
Eric Paris52c923d2009-12-17 21:24:26 -0500666
Eric Paris08ae8932010-05-27 09:41:40 -0400667 pr_debug("%s: flags=%d event_f_flags=%d\n",
668 __func__, flags, event_f_flags);
Eric Paris52c923d2009-12-17 21:24:26 -0500669
Eric Paris52c923d2009-12-17 21:24:26 -0500670 if (!capable(CAP_SYS_ADMIN))
Andreas Gruenbachera2f13ad2010-08-24 12:58:54 +0200671 return -EPERM;
Eric Paris52c923d2009-12-17 21:24:26 -0500672
673 if (flags & ~FAN_ALL_INIT_FLAGS)
674 return -EINVAL;
675
Eric Paris4afeff82010-10-28 17:21:58 -0400676 user = get_current_user();
677 if (atomic_read(&user->fanotify_listeners) > FANOTIFY_DEFAULT_MAX_LISTENERS) {
678 free_uid(user);
679 return -EMFILE;
680 }
681
Eric Parisb2d87902009-12-17 21:24:34 -0500682 f_flags = O_RDWR | FMODE_NONOTIFY;
Eric Paris52c923d2009-12-17 21:24:26 -0500683 if (flags & FAN_CLOEXEC)
684 f_flags |= O_CLOEXEC;
685 if (flags & FAN_NONBLOCK)
686 f_flags |= O_NONBLOCK;
687
688 /* fsnotify_alloc_group takes a ref. Dropped in fanotify_release */
689 group = fsnotify_alloc_group(&fanotify_fsnotify_ops);
690 if (IS_ERR(group))
691 return PTR_ERR(group);
692
Eric Paris4afeff82010-10-28 17:21:58 -0400693 group->fanotify_data.user = user;
694 atomic_inc(&user->fanotify_listeners);
695
Eric Paris80af2582010-07-28 10:18:37 -0400696 group->fanotify_data.f_flags = event_f_flags;
Eric Paris9e66e422009-12-17 21:24:34 -0500697#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
698 mutex_init(&group->fanotify_data.access_mutex);
699 init_waitqueue_head(&group->fanotify_data.access_waitq);
700 INIT_LIST_HEAD(&group->fanotify_data.access_list);
701#endif
Eric Paris4231a232010-10-28 17:21:56 -0400702 switch (flags & FAN_ALL_CLASS_BITS) {
703 case FAN_CLASS_NOTIF:
704 group->priority = FS_PRIO_0;
705 break;
706 case FAN_CLASS_CONTENT:
707 group->priority = FS_PRIO_1;
708 break;
709 case FAN_CLASS_PRE_CONTENT:
710 group->priority = FS_PRIO_2;
711 break;
712 default:
713 fd = -EINVAL;
714 goto out_put_group;
715 }
Eric Pariscb2d4292009-12-17 21:24:34 -0500716
Eric Paris5dd03f52010-10-28 17:21:57 -0400717 if (flags & FAN_UNLIMITED_QUEUE) {
718 fd = -EPERM;
719 if (!capable(CAP_SYS_ADMIN))
720 goto out_put_group;
721 group->max_events = UINT_MAX;
722 } else {
723 group->max_events = FANOTIFY_DEFAULT_MAX_EVENTS;
724 }
Eric Paris2529a0d2010-10-28 17:21:57 -0400725
Eric Parisac7e22d2010-10-28 17:21:58 -0400726 if (flags & FAN_UNLIMITED_MARKS) {
727 fd = -EPERM;
728 if (!capable(CAP_SYS_ADMIN))
729 goto out_put_group;
730 group->fanotify_data.max_marks = UINT_MAX;
731 } else {
732 group->fanotify_data.max_marks = FANOTIFY_DEFAULT_MAX_MARKS;
733 }
Eric Parise7099d82010-10-28 17:21:57 -0400734
Eric Paris52c923d2009-12-17 21:24:26 -0500735 fd = anon_inode_getfd("[fanotify]", &fanotify_fops, group, f_flags);
736 if (fd < 0)
737 goto out_put_group;
738
739 return fd;
740
741out_put_group:
742 fsnotify_put_group(group);
743 return fd;
Eric Paris11637e42009-12-17 21:24:25 -0500744}
Eric Parisbbaa4162009-12-17 21:24:26 -0500745
Heiko Carstens9bbfc962009-12-17 21:24:26 -0500746SYSCALL_DEFINE(fanotify_mark)(int fanotify_fd, unsigned int flags,
747 __u64 mask, int dfd,
748 const char __user * pathname)
Eric Parisbbaa4162009-12-17 21:24:26 -0500749{
Eric Paris0ff21db2009-12-17 21:24:29 -0500750 struct inode *inode = NULL;
751 struct vfsmount *mnt = NULL;
Eric Paris2a3edf82009-12-17 21:24:26 -0500752 struct fsnotify_group *group;
753 struct file *filp;
754 struct path path;
755 int ret, fput_needed;
756
757 pr_debug("%s: fanotify_fd=%d flags=%x dfd=%d pathname=%p mask=%llx\n",
758 __func__, fanotify_fd, flags, dfd, pathname, mask);
759
760 /* we only use the lower 32 bits as of right now. */
761 if (mask & ((__u64)0xffffffff << 32))
762 return -EINVAL;
763
Andreas Gruenbacher88380fe2009-12-17 21:24:29 -0500764 if (flags & ~FAN_ALL_MARK_FLAGS)
765 return -EINVAL;
Eric Paris4d926042009-12-17 21:24:34 -0500766 switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) {
Andreas Gruenbacher88380fe2009-12-17 21:24:29 -0500767 case FAN_MARK_ADD:
768 case FAN_MARK_REMOVE:
Eric Paris4d926042009-12-17 21:24:34 -0500769 case FAN_MARK_FLUSH:
Andreas Gruenbacher88380fe2009-12-17 21:24:29 -0500770 break;
771 default:
772 return -EINVAL;
773 }
Eric Paris8fcd6522010-10-28 17:21:59 -0400774
775 if (mask & FAN_ONDIR) {
776 flags |= FAN_MARK_ONDIR;
777 mask &= ~FAN_ONDIR;
778 }
779
Eric Parisb2d87902009-12-17 21:24:34 -0500780#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
781 if (mask & ~(FAN_ALL_EVENTS | FAN_ALL_PERM_EVENTS | FAN_EVENT_ON_CHILD))
782#else
Andreas Gruenbacher88380fe2009-12-17 21:24:29 -0500783 if (mask & ~(FAN_ALL_EVENTS | FAN_EVENT_ON_CHILD))
Eric Parisb2d87902009-12-17 21:24:34 -0500784#endif
Eric Paris2a3edf82009-12-17 21:24:26 -0500785 return -EINVAL;
786
787 filp = fget_light(fanotify_fd, &fput_needed);
788 if (unlikely(!filp))
789 return -EBADF;
790
791 /* verify that this is indeed an fanotify instance */
792 ret = -EINVAL;
793 if (unlikely(filp->f_op != &fanotify_fops))
794 goto fput_and_out;
Eric Paris4231a232010-10-28 17:21:56 -0400795 group = filp->private_data;
796
797 /*
798 * group->priority == FS_PRIO_0 == FAN_CLASS_NOTIF. These are not
799 * allowed to set permissions events.
800 */
801 ret = -EINVAL;
802 if (mask & FAN_ALL_PERM_EVENTS &&
803 group->priority == FS_PRIO_0)
804 goto fput_and_out;
Eric Paris2a3edf82009-12-17 21:24:26 -0500805
806 ret = fanotify_find_path(dfd, pathname, &path, flags);
807 if (ret)
808 goto fput_and_out;
809
810 /* inode held in place by reference to path; group by fget on fd */
Andreas Gruenbachereac8e9e2009-12-17 21:24:29 -0500811 if (!(flags & FAN_MARK_MOUNT))
Eric Paris0ff21db2009-12-17 21:24:29 -0500812 inode = path.dentry->d_inode;
813 else
814 mnt = path.mnt;
Eric Paris2a3edf82009-12-17 21:24:26 -0500815
816 /* create/update an inode mark */
Eric Paris4d926042009-12-17 21:24:34 -0500817 switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) {
Andreas Gruenbacherc6223f42009-12-17 21:24:28 -0500818 case FAN_MARK_ADD:
Andreas Gruenbachereac8e9e2009-12-17 21:24:29 -0500819 if (flags & FAN_MARK_MOUNT)
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500820 ret = fanotify_add_vfsmount_mark(group, mnt, mask, flags);
Eric Paris0ff21db2009-12-17 21:24:29 -0500821 else
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500822 ret = fanotify_add_inode_mark(group, inode, mask, flags);
Andreas Gruenbacherc6223f42009-12-17 21:24:28 -0500823 break;
824 case FAN_MARK_REMOVE:
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500825 if (flags & FAN_MARK_MOUNT)
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500826 ret = fanotify_remove_vfsmount_mark(group, mnt, mask, flags);
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500827 else
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500828 ret = fanotify_remove_inode_mark(group, inode, mask, flags);
Andreas Gruenbacherc6223f42009-12-17 21:24:28 -0500829 break;
Eric Paris4d926042009-12-17 21:24:34 -0500830 case FAN_MARK_FLUSH:
831 if (flags & FAN_MARK_MOUNT)
832 fsnotify_clear_vfsmount_marks_by_group(group);
833 else
834 fsnotify_clear_inode_marks_by_group(group);
Eric Paris4d926042009-12-17 21:24:34 -0500835 break;
Andreas Gruenbacherc6223f42009-12-17 21:24:28 -0500836 default:
837 ret = -EINVAL;
838 }
Eric Paris2a3edf82009-12-17 21:24:26 -0500839
840 path_put(&path);
841fput_and_out:
842 fput_light(filp, fput_needed);
843 return ret;
Eric Parisbbaa4162009-12-17 21:24:26 -0500844}
Eric Paris2a3edf82009-12-17 21:24:26 -0500845
Heiko Carstens9bbfc962009-12-17 21:24:26 -0500846#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
847asmlinkage long SyS_fanotify_mark(long fanotify_fd, long flags, __u64 mask,
848 long dfd, long pathname)
849{
850 return SYSC_fanotify_mark((int) fanotify_fd, (unsigned int) flags,
851 mask, (int) dfd,
852 (const char __user *) pathname);
853}
854SYSCALL_ALIAS(sys_fanotify_mark, SyS_fanotify_mark);
855#endif
856
Eric Paris2a3edf82009-12-17 21:24:26 -0500857/*
858 * fanotify_user_setup - Our initialization function. Note that we cannnot return
859 * error because we have compiled-in VFS hooks. So an (unlikely) failure here
860 * must result in panic().
861 */
862static int __init fanotify_user_setup(void)
863{
864 fanotify_mark_cache = KMEM_CACHE(fsnotify_mark, SLAB_PANIC);
Eric Parisb2d87902009-12-17 21:24:34 -0500865 fanotify_response_event_cache = KMEM_CACHE(fanotify_response_event,
866 SLAB_PANIC);
Eric Paris2a3edf82009-12-17 21:24:26 -0500867
868 return 0;
869}
870device_initcall(fanotify_user_setup);