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Commit | Line | Data |
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33d3dfff | 1 | #include <linux/fanotify.h> |
11637e4b | 2 | #include <linux/fcntl.h> |
2a3edf86 | 3 | #include <linux/file.h> |
11637e4b | 4 | #include <linux/fs.h> |
52c923dd | 5 | #include <linux/anon_inodes.h> |
11637e4b | 6 | #include <linux/fsnotify_backend.h> |
2a3edf86 | 7 | #include <linux/init.h> |
a1014f10 | 8 | #include <linux/mount.h> |
2a3edf86 | 9 | #include <linux/namei.h> |
a1014f10 | 10 | #include <linux/poll.h> |
11637e4b EP |
11 | #include <linux/security.h> |
12 | #include <linux/syscalls.h> | |
e4e047a2 | 13 | #include <linux/slab.h> |
2a3edf86 | 14 | #include <linux/types.h> |
a1014f10 EP |
15 | #include <linux/uaccess.h> |
16 | ||
17 | #include <asm/ioctls.h> | |
11637e4b | 18 | |
2529a0df | 19 | #define FANOTIFY_DEFAULT_MAX_EVENTS 16384 |
e7099d8a | 20 | #define FANOTIFY_DEFAULT_MAX_MARKS 8192 |
4afeff85 | 21 | #define FANOTIFY_DEFAULT_MAX_LISTENERS 128 |
2529a0df | 22 | |
33d3dfff | 23 | extern const struct fsnotify_ops fanotify_fsnotify_ops; |
11637e4b | 24 | |
2a3edf86 | 25 | static struct kmem_cache *fanotify_mark_cache __read_mostly; |
b2d87909 EP |
26 | static struct kmem_cache *fanotify_response_event_cache __read_mostly; |
27 | ||
28 | struct fanotify_response_event { | |
29 | struct list_head list; | |
30 | __s32 fd; | |
31 | struct fsnotify_event *event; | |
32 | }; | |
2a3edf86 | 33 | |
a1014f10 EP |
34 | /* |
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 | */ | |
41 | static 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 | ||
22aa425d | 59 | static int create_fd(struct fsnotify_group *group, struct fsnotify_event *event) |
a1014f10 EP |
60 | { |
61 | int client_fd; | |
62 | struct dentry *dentry; | |
63 | struct vfsmount *mnt; | |
64 | struct file *new_file; | |
65 | ||
22aa425d | 66 | pr_debug("%s: group=%p event=%p\n", __func__, group, event); |
a1014f10 EP |
67 | |
68 | client_fd = get_unused_fd(); | |
69 | if (client_fd < 0) | |
70 | return client_fd; | |
71 | ||
2069601b | 72 | if (event->data_type != FSNOTIFY_EVENT_PATH) { |
a1014f10 EP |
73 | 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 | */ | |
2069601b LT |
82 | dentry = dget(event->path.dentry); |
83 | mnt = mntget(event->path.mnt); | |
a1014f10 EP |
84 | /* 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, | |
80af2588 | 88 | group->fanotify_data.f_flags | FMODE_NONOTIFY, |
a1014f10 EP |
89 | 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 | ||
22aa425d | 106 | return client_fd; |
a1014f10 EP |
107 | } |
108 | ||
ecf6f5e7 | 109 | static int fill_event_metadata(struct fsnotify_group *group, |
a1014f10 EP |
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; | |
33d3dfff | 118 | metadata->mask = event->mask & FAN_ALL_OUTGOING_EVENTS; |
32c32632 | 119 | metadata->pid = pid_vnr(event->tgid); |
22aa425d | 120 | metadata->fd = create_fd(group, event); |
a1014f10 | 121 | |
22aa425d | 122 | return metadata->fd; |
a1014f10 EP |
123 | } |
124 | ||
b2d87909 EP |
125 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
126 | static 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 | ||
147 | static 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 | ||
185 | static 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); | |
2eebf582 EP |
202 | |
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 | ||
b2d87909 EP |
210 | list_add_tail(&re->list, &group->fanotify_data.access_list); |
211 | mutex_unlock(&group->fanotify_data.access_mutex); | |
212 | ||
213 | return 0; | |
214 | } | |
215 | ||
216 | static 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 | |
236 | static int prepare_for_access_response(struct fsnotify_group *group, | |
237 | struct fsnotify_event *event, | |
238 | __s32 fd) | |
239 | { | |
240 | return 0; | |
241 | } | |
242 | ||
243 | static void remove_access_response(struct fsnotify_group *group, | |
244 | struct fsnotify_event *event, | |
245 | __s32 fd) | |
246 | { | |
8860f060 | 247 | return; |
b2d87909 EP |
248 | } |
249 | #endif | |
250 | ||
a1014f10 EP |
251 | static 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; | |
b2d87909 | 256 | int fd, ret; |
a1014f10 EP |
257 | |
258 | pr_debug("%s: group=%p event=%p\n", __func__, group, event); | |
259 | ||
ecf6f5e7 EP |
260 | ret = fill_event_metadata(group, &fanotify_event_metadata, event); |
261 | if (ret < 0) | |
262 | goto out; | |
b2d87909 | 263 | |
ecf6f5e7 | 264 | fd = ret; |
b2d87909 EP |
265 | ret = prepare_for_access_response(group, event, fd); |
266 | if (ret) | |
267 | goto out_close_fd; | |
a1014f10 | 268 | |
b2d87909 | 269 | ret = -EFAULT; |
a1014f10 | 270 | if (copy_to_user(buf, &fanotify_event_metadata, FAN_EVENT_METADATA_LEN)) |
b2d87909 | 271 | goto out_kill_access_response; |
a1014f10 EP |
272 | |
273 | return FAN_EVENT_METADATA_LEN; | |
b2d87909 EP |
274 | |
275 | out_kill_access_response: | |
276 | remove_access_response(group, event, fd); | |
277 | out_close_fd: | |
278 | sys_close(fd); | |
ecf6f5e7 EP |
279 | out: |
280 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS | |
281 | if (event->mask & FAN_ALL_PERM_EVENTS) { | |
282 | event->response = FAN_DENY; | |
283 | wake_up(&group->fanotify_data.access_waitq); | |
284 | } | |
285 | #endif | |
b2d87909 | 286 | return ret; |
a1014f10 EP |
287 | } |
288 | ||
289 | /* intofiy userspace file descriptor functions */ | |
290 | static unsigned int fanotify_poll(struct file *file, poll_table *wait) | |
291 | { | |
292 | struct fsnotify_group *group = file->private_data; | |
293 | int ret = 0; | |
294 | ||
295 | poll_wait(file, &group->notification_waitq, wait); | |
296 | mutex_lock(&group->notification_mutex); | |
297 | if (!fsnotify_notify_queue_is_empty(group)) | |
298 | ret = POLLIN | POLLRDNORM; | |
299 | mutex_unlock(&group->notification_mutex); | |
300 | ||
301 | return ret; | |
302 | } | |
303 | ||
304 | static ssize_t fanotify_read(struct file *file, char __user *buf, | |
305 | size_t count, loff_t *pos) | |
306 | { | |
307 | struct fsnotify_group *group; | |
308 | struct fsnotify_event *kevent; | |
309 | char __user *start; | |
310 | int ret; | |
311 | DEFINE_WAIT(wait); | |
312 | ||
313 | start = buf; | |
314 | group = file->private_data; | |
315 | ||
316 | pr_debug("%s: group=%p\n", __func__, group); | |
317 | ||
318 | while (1) { | |
319 | prepare_to_wait(&group->notification_waitq, &wait, TASK_INTERRUPTIBLE); | |
320 | ||
321 | mutex_lock(&group->notification_mutex); | |
322 | kevent = get_one_event(group, count); | |
323 | mutex_unlock(&group->notification_mutex); | |
324 | ||
325 | if (kevent) { | |
326 | ret = PTR_ERR(kevent); | |
327 | if (IS_ERR(kevent)) | |
328 | break; | |
329 | ret = copy_event_to_user(group, kevent, buf); | |
330 | fsnotify_put_event(kevent); | |
331 | if (ret < 0) | |
332 | break; | |
333 | buf += ret; | |
334 | count -= ret; | |
335 | continue; | |
336 | } | |
337 | ||
338 | ret = -EAGAIN; | |
339 | if (file->f_flags & O_NONBLOCK) | |
340 | break; | |
1a5cea72 | 341 | ret = -ERESTARTSYS; |
a1014f10 EP |
342 | if (signal_pending(current)) |
343 | break; | |
344 | ||
345 | if (start != buf) | |
346 | break; | |
347 | ||
348 | schedule(); | |
349 | } | |
350 | ||
351 | finish_wait(&group->notification_waitq, &wait); | |
352 | if (start != buf && ret != -EFAULT) | |
353 | ret = buf - start; | |
354 | return ret; | |
355 | } | |
356 | ||
b2d87909 EP |
357 | static ssize_t fanotify_write(struct file *file, const char __user *buf, size_t count, loff_t *pos) |
358 | { | |
359 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS | |
360 | struct fanotify_response response = { .fd = -1, .response = -1 }; | |
361 | struct fsnotify_group *group; | |
362 | int ret; | |
363 | ||
364 | group = file->private_data; | |
365 | ||
366 | if (count > sizeof(response)) | |
367 | count = sizeof(response); | |
368 | ||
369 | pr_debug("%s: group=%p count=%zu\n", __func__, group, count); | |
370 | ||
371 | if (copy_from_user(&response, buf, count)) | |
372 | return -EFAULT; | |
373 | ||
374 | ret = process_access_response(group, &response); | |
375 | if (ret < 0) | |
376 | count = ret; | |
377 | ||
378 | return count; | |
379 | #else | |
380 | return -EINVAL; | |
381 | #endif | |
382 | } | |
383 | ||
52c923dd EP |
384 | static int fanotify_release(struct inode *ignored, struct file *file) |
385 | { | |
386 | struct fsnotify_group *group = file->private_data; | |
52c923dd | 387 | |
2eebf582 | 388 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
19ba54f4 AM |
389 | struct fanotify_response_event *re, *lre; |
390 | ||
2eebf582 EP |
391 | mutex_lock(&group->fanotify_data.access_mutex); |
392 | ||
393 | group->fanotify_data.bypass_perm = true; | |
394 | ||
395 | list_for_each_entry_safe(re, lre, &group->fanotify_data.access_list, list) { | |
396 | pr_debug("%s: found group=%p re=%p event=%p\n", __func__, group, | |
397 | re, re->event); | |
398 | ||
399 | list_del_init(&re->list); | |
400 | re->event->response = FAN_ALLOW; | |
401 | ||
402 | kmem_cache_free(fanotify_response_event_cache, re); | |
403 | } | |
404 | mutex_unlock(&group->fanotify_data.access_mutex); | |
405 | ||
406 | wake_up(&group->fanotify_data.access_waitq); | |
407 | #endif | |
52c923dd EP |
408 | /* matches the fanotify_init->fsnotify_alloc_group */ |
409 | fsnotify_put_group(group); | |
410 | ||
411 | return 0; | |
412 | } | |
413 | ||
a1014f10 EP |
414 | static long fanotify_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
415 | { | |
416 | struct fsnotify_group *group; | |
417 | struct fsnotify_event_holder *holder; | |
418 | void __user *p; | |
419 | int ret = -ENOTTY; | |
420 | size_t send_len = 0; | |
421 | ||
422 | group = file->private_data; | |
423 | ||
424 | p = (void __user *) arg; | |
425 | ||
426 | switch (cmd) { | |
427 | case FIONREAD: | |
428 | mutex_lock(&group->notification_mutex); | |
429 | list_for_each_entry(holder, &group->notification_list, event_list) | |
430 | send_len += FAN_EVENT_METADATA_LEN; | |
431 | mutex_unlock(&group->notification_mutex); | |
432 | ret = put_user(send_len, (int __user *) p); | |
433 | break; | |
434 | } | |
435 | ||
436 | return ret; | |
437 | } | |
438 | ||
52c923dd | 439 | static const struct file_operations fanotify_fops = { |
a1014f10 EP |
440 | .poll = fanotify_poll, |
441 | .read = fanotify_read, | |
b2d87909 | 442 | .write = fanotify_write, |
52c923dd EP |
443 | .fasync = NULL, |
444 | .release = fanotify_release, | |
a1014f10 EP |
445 | .unlocked_ioctl = fanotify_ioctl, |
446 | .compat_ioctl = fanotify_ioctl, | |
6038f373 | 447 | .llseek = noop_llseek, |
52c923dd EP |
448 | }; |
449 | ||
2a3edf86 EP |
450 | static void fanotify_free_mark(struct fsnotify_mark *fsn_mark) |
451 | { | |
452 | kmem_cache_free(fanotify_mark_cache, fsn_mark); | |
453 | } | |
454 | ||
455 | static int fanotify_find_path(int dfd, const char __user *filename, | |
456 | struct path *path, unsigned int flags) | |
457 | { | |
458 | int ret; | |
459 | ||
460 | pr_debug("%s: dfd=%d filename=%p flags=%x\n", __func__, | |
461 | dfd, filename, flags); | |
462 | ||
463 | if (filename == NULL) { | |
464 | struct file *file; | |
465 | int fput_needed; | |
466 | ||
467 | ret = -EBADF; | |
468 | file = fget_light(dfd, &fput_needed); | |
469 | if (!file) | |
470 | goto out; | |
471 | ||
472 | ret = -ENOTDIR; | |
473 | if ((flags & FAN_MARK_ONLYDIR) && | |
474 | !(S_ISDIR(file->f_path.dentry->d_inode->i_mode))) { | |
475 | fput_light(file, fput_needed); | |
476 | goto out; | |
477 | } | |
478 | ||
479 | *path = file->f_path; | |
480 | path_get(path); | |
481 | fput_light(file, fput_needed); | |
482 | } else { | |
483 | unsigned int lookup_flags = 0; | |
484 | ||
485 | if (!(flags & FAN_MARK_DONT_FOLLOW)) | |
486 | lookup_flags |= LOOKUP_FOLLOW; | |
487 | if (flags & FAN_MARK_ONLYDIR) | |
488 | lookup_flags |= LOOKUP_DIRECTORY; | |
489 | ||
490 | ret = user_path_at(dfd, filename, lookup_flags, path); | |
491 | if (ret) | |
492 | goto out; | |
493 | } | |
494 | ||
495 | /* you can only watch an inode if you have read permissions on it */ | |
496 | ret = inode_permission(path->dentry->d_inode, MAY_READ); | |
497 | if (ret) | |
498 | path_put(path); | |
499 | out: | |
500 | return ret; | |
501 | } | |
502 | ||
b9e4e3bd EP |
503 | static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark, |
504 | __u32 mask, | |
505 | unsigned int flags) | |
088b09b0 AG |
506 | { |
507 | __u32 oldmask; | |
508 | ||
509 | spin_lock(&fsn_mark->lock); | |
b9e4e3bd EP |
510 | if (!(flags & FAN_MARK_IGNORED_MASK)) { |
511 | oldmask = fsn_mark->mask; | |
512 | fsnotify_set_mark_mask_locked(fsn_mark, (oldmask & ~mask)); | |
513 | } else { | |
514 | oldmask = fsn_mark->ignored_mask; | |
515 | fsnotify_set_mark_ignored_mask_locked(fsn_mark, (oldmask & ~mask)); | |
516 | } | |
088b09b0 AG |
517 | spin_unlock(&fsn_mark->lock); |
518 | ||
519 | if (!(oldmask & ~mask)) | |
520 | fsnotify_destroy_mark(fsn_mark); | |
521 | ||
522 | return mask & oldmask; | |
523 | } | |
524 | ||
f3640192 | 525 | static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group, |
b9e4e3bd EP |
526 | struct vfsmount *mnt, __u32 mask, |
527 | unsigned int flags) | |
88826276 EP |
528 | { |
529 | struct fsnotify_mark *fsn_mark = NULL; | |
088b09b0 | 530 | __u32 removed; |
88826276 | 531 | |
f3640192 AG |
532 | fsn_mark = fsnotify_find_vfsmount_mark(group, mnt); |
533 | if (!fsn_mark) | |
534 | return -ENOENT; | |
88826276 | 535 | |
b9e4e3bd | 536 | removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags); |
f3640192 | 537 | fsnotify_put_mark(fsn_mark); |
f3640192 AG |
538 | if (removed & mnt->mnt_fsnotify_mask) |
539 | fsnotify_recalc_vfsmount_mask(mnt); | |
540 | ||
541 | return 0; | |
542 | } | |
2a3edf86 | 543 | |
f3640192 | 544 | static int fanotify_remove_inode_mark(struct fsnotify_group *group, |
b9e4e3bd EP |
545 | struct inode *inode, __u32 mask, |
546 | unsigned int flags) | |
f3640192 AG |
547 | { |
548 | struct fsnotify_mark *fsn_mark = NULL; | |
549 | __u32 removed; | |
550 | ||
551 | fsn_mark = fsnotify_find_inode_mark(group, inode); | |
88826276 EP |
552 | if (!fsn_mark) |
553 | return -ENOENT; | |
554 | ||
b9e4e3bd | 555 | removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags); |
5444e298 | 556 | /* matches the fsnotify_find_inode_mark() */ |
2a3edf86 | 557 | fsnotify_put_mark(fsn_mark); |
f3640192 AG |
558 | if (removed & inode->i_fsnotify_mask) |
559 | fsnotify_recalc_inode_mask(inode); | |
088b09b0 | 560 | |
2a3edf86 EP |
561 | return 0; |
562 | } | |
563 | ||
b9e4e3bd EP |
564 | static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark, |
565 | __u32 mask, | |
566 | unsigned int flags) | |
912ee394 | 567 | { |
192ca4d1 | 568 | __u32 oldmask = -1; |
912ee394 AG |
569 | |
570 | spin_lock(&fsn_mark->lock); | |
b9e4e3bd EP |
571 | if (!(flags & FAN_MARK_IGNORED_MASK)) { |
572 | oldmask = fsn_mark->mask; | |
573 | fsnotify_set_mark_mask_locked(fsn_mark, (oldmask | mask)); | |
574 | } else { | |
192ca4d1 EP |
575 | __u32 tmask = fsn_mark->ignored_mask | mask; |
576 | fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask); | |
c9778a98 EP |
577 | if (flags & FAN_MARK_IGNORED_SURV_MODIFY) |
578 | fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY; | |
b9e4e3bd | 579 | } |
8fcd6528 EP |
580 | |
581 | if (!(flags & FAN_MARK_ONDIR)) { | |
582 | __u32 tmask = fsn_mark->ignored_mask | FAN_ONDIR; | |
583 | fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask); | |
584 | } | |
585 | ||
912ee394 AG |
586 | spin_unlock(&fsn_mark->lock); |
587 | ||
588 | return mask & ~oldmask; | |
589 | } | |
590 | ||
52202dfb | 591 | static int fanotify_add_vfsmount_mark(struct fsnotify_group *group, |
b9e4e3bd EP |
592 | struct vfsmount *mnt, __u32 mask, |
593 | unsigned int flags) | |
2a3edf86 EP |
594 | { |
595 | struct fsnotify_mark *fsn_mark; | |
912ee394 | 596 | __u32 added; |
fa218ab9 | 597 | int ret = 0; |
2a3edf86 | 598 | |
88826276 EP |
599 | fsn_mark = fsnotify_find_vfsmount_mark(group, mnt); |
600 | if (!fsn_mark) { | |
e7099d8a EP |
601 | if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks) |
602 | return -ENOSPC; | |
603 | ||
912ee394 AG |
604 | fsn_mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL); |
605 | if (!fsn_mark) | |
52202dfb | 606 | return -ENOMEM; |
88826276 | 607 | |
912ee394 AG |
608 | fsnotify_init_mark(fsn_mark, fanotify_free_mark); |
609 | ret = fsnotify_add_mark(fsn_mark, group, NULL, mnt, 0); | |
fa218ab9 LS |
610 | if (ret) |
611 | goto err; | |
88826276 | 612 | } |
b9e4e3bd | 613 | added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); |
fa218ab9 | 614 | |
43709a28 EP |
615 | if (added & ~mnt->mnt_fsnotify_mask) |
616 | fsnotify_recalc_vfsmount_mask(mnt); | |
fa218ab9 LS |
617 | err: |
618 | fsnotify_put_mark(fsn_mark); | |
619 | return ret; | |
88826276 EP |
620 | } |
621 | ||
52202dfb | 622 | static int fanotify_add_inode_mark(struct fsnotify_group *group, |
b9e4e3bd EP |
623 | struct inode *inode, __u32 mask, |
624 | unsigned int flags) | |
88826276 EP |
625 | { |
626 | struct fsnotify_mark *fsn_mark; | |
912ee394 | 627 | __u32 added; |
fa218ab9 | 628 | int ret = 0; |
88826276 EP |
629 | |
630 | pr_debug("%s: group=%p inode=%p\n", __func__, group, inode); | |
2a3edf86 | 631 | |
5322a59f EP |
632 | /* |
633 | * If some other task has this inode open for write we should not add | |
634 | * an ignored mark, unless that ignored mark is supposed to survive | |
635 | * modification changes anyway. | |
636 | */ | |
637 | if ((flags & FAN_MARK_IGNORED_MASK) && | |
638 | !(flags & FAN_MARK_IGNORED_SURV_MODIFY) && | |
639 | (atomic_read(&inode->i_writecount) > 0)) | |
640 | return 0; | |
641 | ||
5444e298 | 642 | fsn_mark = fsnotify_find_inode_mark(group, inode); |
2a3edf86 | 643 | if (!fsn_mark) { |
e7099d8a EP |
644 | if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks) |
645 | return -ENOSPC; | |
646 | ||
912ee394 AG |
647 | fsn_mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL); |
648 | if (!fsn_mark) | |
52202dfb | 649 | return -ENOMEM; |
2a3edf86 | 650 | |
912ee394 AG |
651 | fsnotify_init_mark(fsn_mark, fanotify_free_mark); |
652 | ret = fsnotify_add_mark(fsn_mark, group, inode, NULL, 0); | |
fa218ab9 LS |
653 | if (ret) |
654 | goto err; | |
2a3edf86 | 655 | } |
b9e4e3bd | 656 | added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); |
fa218ab9 | 657 | |
43709a28 EP |
658 | if (added & ~inode->i_fsnotify_mask) |
659 | fsnotify_recalc_inode_mask(inode); | |
fa218ab9 LS |
660 | err: |
661 | fsnotify_put_mark(fsn_mark); | |
662 | return ret; | |
88826276 | 663 | } |
2a3edf86 | 664 | |
52c923dd | 665 | /* fanotify syscalls */ |
08ae8938 | 666 | SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) |
11637e4b | 667 | { |
52c923dd EP |
668 | struct fsnotify_group *group; |
669 | int f_flags, fd; | |
4afeff85 | 670 | struct user_struct *user; |
52c923dd | 671 | |
08ae8938 EP |
672 | pr_debug("%s: flags=%d event_f_flags=%d\n", |
673 | __func__, flags, event_f_flags); | |
52c923dd | 674 | |
52c923dd | 675 | if (!capable(CAP_SYS_ADMIN)) |
a2f13ad0 | 676 | return -EPERM; |
52c923dd EP |
677 | |
678 | if (flags & ~FAN_ALL_INIT_FLAGS) | |
679 | return -EINVAL; | |
680 | ||
4afeff85 EP |
681 | user = get_current_user(); |
682 | if (atomic_read(&user->fanotify_listeners) > FANOTIFY_DEFAULT_MAX_LISTENERS) { | |
683 | free_uid(user); | |
684 | return -EMFILE; | |
685 | } | |
686 | ||
b2d87909 | 687 | f_flags = O_RDWR | FMODE_NONOTIFY; |
52c923dd EP |
688 | if (flags & FAN_CLOEXEC) |
689 | f_flags |= O_CLOEXEC; | |
690 | if (flags & FAN_NONBLOCK) | |
691 | f_flags |= O_NONBLOCK; | |
692 | ||
693 | /* fsnotify_alloc_group takes a ref. Dropped in fanotify_release */ | |
694 | group = fsnotify_alloc_group(&fanotify_fsnotify_ops); | |
695 | if (IS_ERR(group)) | |
696 | return PTR_ERR(group); | |
697 | ||
4afeff85 EP |
698 | group->fanotify_data.user = user; |
699 | atomic_inc(&user->fanotify_listeners); | |
700 | ||
80af2588 | 701 | group->fanotify_data.f_flags = event_f_flags; |
9e66e423 EP |
702 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
703 | mutex_init(&group->fanotify_data.access_mutex); | |
704 | init_waitqueue_head(&group->fanotify_data.access_waitq); | |
705 | INIT_LIST_HEAD(&group->fanotify_data.access_list); | |
706 | #endif | |
4231a235 EP |
707 | switch (flags & FAN_ALL_CLASS_BITS) { |
708 | case FAN_CLASS_NOTIF: | |
709 | group->priority = FS_PRIO_0; | |
710 | break; | |
711 | case FAN_CLASS_CONTENT: | |
712 | group->priority = FS_PRIO_1; | |
713 | break; | |
714 | case FAN_CLASS_PRE_CONTENT: | |
715 | group->priority = FS_PRIO_2; | |
716 | break; | |
717 | default: | |
718 | fd = -EINVAL; | |
719 | goto out_put_group; | |
720 | } | |
cb2d429f | 721 | |
5dd03f55 EP |
722 | if (flags & FAN_UNLIMITED_QUEUE) { |
723 | fd = -EPERM; | |
724 | if (!capable(CAP_SYS_ADMIN)) | |
725 | goto out_put_group; | |
726 | group->max_events = UINT_MAX; | |
727 | } else { | |
728 | group->max_events = FANOTIFY_DEFAULT_MAX_EVENTS; | |
729 | } | |
2529a0df | 730 | |
ac7e22dc EP |
731 | if (flags & FAN_UNLIMITED_MARKS) { |
732 | fd = -EPERM; | |
733 | if (!capable(CAP_SYS_ADMIN)) | |
734 | goto out_put_group; | |
735 | group->fanotify_data.max_marks = UINT_MAX; | |
736 | } else { | |
737 | group->fanotify_data.max_marks = FANOTIFY_DEFAULT_MAX_MARKS; | |
738 | } | |
e7099d8a | 739 | |
52c923dd EP |
740 | fd = anon_inode_getfd("[fanotify]", &fanotify_fops, group, f_flags); |
741 | if (fd < 0) | |
742 | goto out_put_group; | |
743 | ||
744 | return fd; | |
745 | ||
746 | out_put_group: | |
747 | fsnotify_put_group(group); | |
748 | return fd; | |
11637e4b | 749 | } |
bbaa4168 | 750 | |
9bbfc964 HC |
751 | SYSCALL_DEFINE(fanotify_mark)(int fanotify_fd, unsigned int flags, |
752 | __u64 mask, int dfd, | |
753 | const char __user * pathname) | |
bbaa4168 | 754 | { |
0ff21db9 EP |
755 | struct inode *inode = NULL; |
756 | struct vfsmount *mnt = NULL; | |
2a3edf86 EP |
757 | struct fsnotify_group *group; |
758 | struct file *filp; | |
759 | struct path path; | |
760 | int ret, fput_needed; | |
761 | ||
762 | pr_debug("%s: fanotify_fd=%d flags=%x dfd=%d pathname=%p mask=%llx\n", | |
763 | __func__, fanotify_fd, flags, dfd, pathname, mask); | |
764 | ||
765 | /* we only use the lower 32 bits as of right now. */ | |
766 | if (mask & ((__u64)0xffffffff << 32)) | |
767 | return -EINVAL; | |
768 | ||
88380fe6 AG |
769 | if (flags & ~FAN_ALL_MARK_FLAGS) |
770 | return -EINVAL; | |
4d92604c | 771 | switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) { |
88380fe6 AG |
772 | case FAN_MARK_ADD: |
773 | case FAN_MARK_REMOVE: | |
4d92604c | 774 | case FAN_MARK_FLUSH: |
88380fe6 AG |
775 | break; |
776 | default: | |
777 | return -EINVAL; | |
778 | } | |
8fcd6528 EP |
779 | |
780 | if (mask & FAN_ONDIR) { | |
781 | flags |= FAN_MARK_ONDIR; | |
782 | mask &= ~FAN_ONDIR; | |
783 | } | |
784 | ||
b2d87909 EP |
785 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
786 | if (mask & ~(FAN_ALL_EVENTS | FAN_ALL_PERM_EVENTS | FAN_EVENT_ON_CHILD)) | |
787 | #else | |
88380fe6 | 788 | if (mask & ~(FAN_ALL_EVENTS | FAN_EVENT_ON_CHILD)) |
b2d87909 | 789 | #endif |
2a3edf86 EP |
790 | return -EINVAL; |
791 | ||
792 | filp = fget_light(fanotify_fd, &fput_needed); | |
793 | if (unlikely(!filp)) | |
794 | return -EBADF; | |
795 | ||
796 | /* verify that this is indeed an fanotify instance */ | |
797 | ret = -EINVAL; | |
798 | if (unlikely(filp->f_op != &fanotify_fops)) | |
799 | goto fput_and_out; | |
4231a235 EP |
800 | group = filp->private_data; |
801 | ||
802 | /* | |
803 | * group->priority == FS_PRIO_0 == FAN_CLASS_NOTIF. These are not | |
804 | * allowed to set permissions events. | |
805 | */ | |
806 | ret = -EINVAL; | |
807 | if (mask & FAN_ALL_PERM_EVENTS && | |
808 | group->priority == FS_PRIO_0) | |
809 | goto fput_and_out; | |
2a3edf86 EP |
810 | |
811 | ret = fanotify_find_path(dfd, pathname, &path, flags); | |
812 | if (ret) | |
813 | goto fput_and_out; | |
814 | ||
815 | /* inode held in place by reference to path; group by fget on fd */ | |
eac8e9e8 | 816 | if (!(flags & FAN_MARK_MOUNT)) |
0ff21db9 EP |
817 | inode = path.dentry->d_inode; |
818 | else | |
819 | mnt = path.mnt; | |
2a3edf86 EP |
820 | |
821 | /* create/update an inode mark */ | |
4d92604c | 822 | switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) { |
c6223f46 | 823 | case FAN_MARK_ADD: |
eac8e9e8 | 824 | if (flags & FAN_MARK_MOUNT) |
b9e4e3bd | 825 | ret = fanotify_add_vfsmount_mark(group, mnt, mask, flags); |
0ff21db9 | 826 | else |
b9e4e3bd | 827 | ret = fanotify_add_inode_mark(group, inode, mask, flags); |
c6223f46 AG |
828 | break; |
829 | case FAN_MARK_REMOVE: | |
f3640192 | 830 | if (flags & FAN_MARK_MOUNT) |
b9e4e3bd | 831 | ret = fanotify_remove_vfsmount_mark(group, mnt, mask, flags); |
f3640192 | 832 | else |
b9e4e3bd | 833 | ret = fanotify_remove_inode_mark(group, inode, mask, flags); |
c6223f46 | 834 | break; |
4d92604c EP |
835 | case FAN_MARK_FLUSH: |
836 | if (flags & FAN_MARK_MOUNT) | |
837 | fsnotify_clear_vfsmount_marks_by_group(group); | |
838 | else | |
839 | fsnotify_clear_inode_marks_by_group(group); | |
4d92604c | 840 | break; |
c6223f46 AG |
841 | default: |
842 | ret = -EINVAL; | |
843 | } | |
2a3edf86 EP |
844 | |
845 | path_put(&path); | |
846 | fput_and_out: | |
847 | fput_light(filp, fput_needed); | |
848 | return ret; | |
849 | } | |
850 | ||
9bbfc964 HC |
851 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS |
852 | asmlinkage long SyS_fanotify_mark(long fanotify_fd, long flags, __u64 mask, | |
853 | long dfd, long pathname) | |
854 | { | |
855 | return SYSC_fanotify_mark((int) fanotify_fd, (unsigned int) flags, | |
856 | mask, (int) dfd, | |
857 | (const char __user *) pathname); | |
858 | } | |
859 | SYSCALL_ALIAS(sys_fanotify_mark, SyS_fanotify_mark); | |
860 | #endif | |
861 | ||
2a3edf86 EP |
862 | /* |
863 | * fanotify_user_setup - Our initialization function. Note that we cannnot return | |
864 | * error because we have compiled-in VFS hooks. So an (unlikely) failure here | |
865 | * must result in panic(). | |
866 | */ | |
867 | static int __init fanotify_user_setup(void) | |
868 | { | |
869 | fanotify_mark_cache = KMEM_CACHE(fsnotify_mark, SLAB_PANIC); | |
b2d87909 EP |
870 | fanotify_response_event_cache = KMEM_CACHE(fanotify_response_event, |
871 | SLAB_PANIC); | |
2a3edf86 EP |
872 | |
873 | return 0; | |
bbaa4168 | 874 | } |
2a3edf86 | 875 | device_initcall(fanotify_user_setup); |