Commit | Line | Data |
---|---|---|
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 | |
c63181e6 AV |
19 | #include "../../mount.h" |
20 | ||
2529a0df | 21 | #define FANOTIFY_DEFAULT_MAX_EVENTS 16384 |
e7099d8a | 22 | #define FANOTIFY_DEFAULT_MAX_MARKS 8192 |
4afeff85 | 23 | #define FANOTIFY_DEFAULT_MAX_LISTENERS 128 |
2529a0df | 24 | |
33d3dfff | 25 | extern const struct fsnotify_ops fanotify_fsnotify_ops; |
11637e4b | 26 | |
2a3edf86 | 27 | static struct kmem_cache *fanotify_mark_cache __read_mostly; |
b2d87909 EP |
28 | static struct kmem_cache *fanotify_response_event_cache __read_mostly; |
29 | ||
30 | struct fanotify_response_event { | |
31 | struct list_head list; | |
32 | __s32 fd; | |
33 | struct fsnotify_event *event; | |
34 | }; | |
2a3edf86 | 35 | |
a1014f10 EP |
36 | /* |
37 | * Get an fsnotify notification event if one exists and is small | |
38 | * enough to fit in "count". Return an error pointer if the count | |
39 | * is not large enough. | |
40 | * | |
41 | * Called with the group->notification_mutex held. | |
42 | */ | |
43 | static struct fsnotify_event *get_one_event(struct fsnotify_group *group, | |
44 | size_t count) | |
45 | { | |
46 | BUG_ON(!mutex_is_locked(&group->notification_mutex)); | |
47 | ||
48 | pr_debug("%s: group=%p count=%zd\n", __func__, group, count); | |
49 | ||
50 | if (fsnotify_notify_queue_is_empty(group)) | |
51 | return NULL; | |
52 | ||
53 | if (FAN_EVENT_METADATA_LEN > count) | |
54 | return ERR_PTR(-EINVAL); | |
55 | ||
56 | /* held the notification_mutex the whole time, so this is the | |
57 | * same event we peeked above */ | |
58 | return fsnotify_remove_notify_event(group); | |
59 | } | |
60 | ||
22aa425d | 61 | static int create_fd(struct fsnotify_group *group, struct fsnotify_event *event) |
a1014f10 EP |
62 | { |
63 | int client_fd; | |
a1014f10 EP |
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 | */ | |
a1014f10 EP |
82 | /* it's possible this event was an overflow event. in that case dentry and mnt |
83 | * are NULL; That's fine, just don't call dentry open */ | |
765927b2 AV |
84 | if (event->path.dentry && event->path.mnt) |
85 | new_file = dentry_open(&event->path, | |
80af2588 | 86 | group->fanotify_data.f_flags | FMODE_NONOTIFY, |
a1014f10 EP |
87 | current_cred()); |
88 | else | |
89 | new_file = ERR_PTR(-EOVERFLOW); | |
90 | if (IS_ERR(new_file)) { | |
91 | /* | |
92 | * we still send an event even if we can't open the file. this | |
93 | * can happen when say tasks are gone and we try to open their | |
94 | * /proc files or we try to open a WRONLY file like in sysfs | |
95 | * we just send the errno to userspace since there isn't much | |
96 | * else we can do. | |
97 | */ | |
98 | put_unused_fd(client_fd); | |
99 | client_fd = PTR_ERR(new_file); | |
100 | } else { | |
101 | fd_install(client_fd, new_file); | |
102 | } | |
103 | ||
22aa425d | 104 | return client_fd; |
a1014f10 EP |
105 | } |
106 | ||
ecf6f5e7 | 107 | static int fill_event_metadata(struct fsnotify_group *group, |
a1014f10 EP |
108 | struct fanotify_event_metadata *metadata, |
109 | struct fsnotify_event *event) | |
110 | { | |
fdbf3cee LS |
111 | int ret = 0; |
112 | ||
a1014f10 EP |
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; | |
7d131623 | 117 | metadata->metadata_len = FAN_EVENT_METADATA_LEN; |
a1014f10 | 118 | metadata->vers = FANOTIFY_METADATA_VERSION; |
33d3dfff | 119 | metadata->mask = event->mask & FAN_ALL_OUTGOING_EVENTS; |
32c32632 | 120 | metadata->pid = pid_vnr(event->tgid); |
fdbf3cee LS |
121 | if (unlikely(event->mask & FAN_Q_OVERFLOW)) |
122 | metadata->fd = FAN_NOFD; | |
123 | else { | |
124 | metadata->fd = create_fd(group, event); | |
125 | if (metadata->fd < 0) | |
126 | ret = metadata->fd; | |
127 | } | |
a1014f10 | 128 | |
fdbf3cee | 129 | return ret; |
a1014f10 EP |
130 | } |
131 | ||
b2d87909 EP |
132 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
133 | static struct fanotify_response_event *dequeue_re(struct fsnotify_group *group, | |
134 | __s32 fd) | |
135 | { | |
136 | struct fanotify_response_event *re, *return_re = NULL; | |
137 | ||
138 | mutex_lock(&group->fanotify_data.access_mutex); | |
139 | list_for_each_entry(re, &group->fanotify_data.access_list, list) { | |
140 | if (re->fd != fd) | |
141 | continue; | |
142 | ||
143 | list_del_init(&re->list); | |
144 | return_re = re; | |
145 | break; | |
146 | } | |
147 | mutex_unlock(&group->fanotify_data.access_mutex); | |
148 | ||
149 | pr_debug("%s: found return_re=%p\n", __func__, return_re); | |
150 | ||
151 | return return_re; | |
152 | } | |
153 | ||
154 | static int process_access_response(struct fsnotify_group *group, | |
155 | struct fanotify_response *response_struct) | |
156 | { | |
157 | struct fanotify_response_event *re; | |
158 | __s32 fd = response_struct->fd; | |
159 | __u32 response = response_struct->response; | |
160 | ||
161 | pr_debug("%s: group=%p fd=%d response=%d\n", __func__, group, | |
162 | fd, response); | |
163 | /* | |
164 | * make sure the response is valid, if invalid we do nothing and either | |
25985edc | 165 | * userspace can send a valid response or we will clean it up after the |
b2d87909 EP |
166 | * timeout |
167 | */ | |
168 | switch (response) { | |
169 | case FAN_ALLOW: | |
170 | case FAN_DENY: | |
171 | break; | |
172 | default: | |
173 | return -EINVAL; | |
174 | } | |
175 | ||
176 | if (fd < 0) | |
177 | return -EINVAL; | |
178 | ||
179 | re = dequeue_re(group, fd); | |
180 | if (!re) | |
181 | return -ENOENT; | |
182 | ||
183 | re->event->response = response; | |
184 | ||
185 | wake_up(&group->fanotify_data.access_waitq); | |
186 | ||
187 | kmem_cache_free(fanotify_response_event_cache, re); | |
188 | ||
189 | return 0; | |
190 | } | |
191 | ||
192 | static int prepare_for_access_response(struct fsnotify_group *group, | |
193 | struct fsnotify_event *event, | |
194 | __s32 fd) | |
195 | { | |
196 | struct fanotify_response_event *re; | |
197 | ||
198 | if (!(event->mask & FAN_ALL_PERM_EVENTS)) | |
199 | return 0; | |
200 | ||
201 | re = kmem_cache_alloc(fanotify_response_event_cache, GFP_KERNEL); | |
202 | if (!re) | |
203 | return -ENOMEM; | |
204 | ||
205 | re->event = event; | |
206 | re->fd = fd; | |
207 | ||
208 | mutex_lock(&group->fanotify_data.access_mutex); | |
2eebf582 | 209 | |
09e5f14e | 210 | if (atomic_read(&group->fanotify_data.bypass_perm)) { |
2eebf582 EP |
211 | mutex_unlock(&group->fanotify_data.access_mutex); |
212 | kmem_cache_free(fanotify_response_event_cache, re); | |
213 | event->response = FAN_ALLOW; | |
214 | return 0; | |
215 | } | |
216 | ||
b2d87909 EP |
217 | list_add_tail(&re->list, &group->fanotify_data.access_list); |
218 | mutex_unlock(&group->fanotify_data.access_mutex); | |
219 | ||
220 | return 0; | |
221 | } | |
222 | ||
223 | static void remove_access_response(struct fsnotify_group *group, | |
224 | struct fsnotify_event *event, | |
225 | __s32 fd) | |
226 | { | |
227 | struct fanotify_response_event *re; | |
228 | ||
229 | if (!(event->mask & FAN_ALL_PERM_EVENTS)) | |
230 | return; | |
231 | ||
232 | re = dequeue_re(group, fd); | |
233 | if (!re) | |
234 | return; | |
235 | ||
236 | BUG_ON(re->event != event); | |
237 | ||
238 | kmem_cache_free(fanotify_response_event_cache, re); | |
239 | ||
240 | return; | |
241 | } | |
242 | #else | |
243 | static int prepare_for_access_response(struct fsnotify_group *group, | |
244 | struct fsnotify_event *event, | |
245 | __s32 fd) | |
246 | { | |
247 | return 0; | |
248 | } | |
249 | ||
250 | static void remove_access_response(struct fsnotify_group *group, | |
251 | struct fsnotify_event *event, | |
252 | __s32 fd) | |
253 | { | |
8860f060 | 254 | return; |
b2d87909 EP |
255 | } |
256 | #endif | |
257 | ||
a1014f10 EP |
258 | static ssize_t copy_event_to_user(struct fsnotify_group *group, |
259 | struct fsnotify_event *event, | |
260 | char __user *buf) | |
261 | { | |
262 | struct fanotify_event_metadata fanotify_event_metadata; | |
b2d87909 | 263 | int fd, ret; |
a1014f10 EP |
264 | |
265 | pr_debug("%s: group=%p event=%p\n", __func__, group, event); | |
266 | ||
ecf6f5e7 EP |
267 | ret = fill_event_metadata(group, &fanotify_event_metadata, event); |
268 | if (ret < 0) | |
269 | goto out; | |
b2d87909 | 270 | |
fdbf3cee | 271 | fd = fanotify_event_metadata.fd; |
b2d87909 EP |
272 | ret = prepare_for_access_response(group, event, fd); |
273 | if (ret) | |
274 | goto out_close_fd; | |
a1014f10 | 275 | |
b2d87909 | 276 | ret = -EFAULT; |
7d131623 EP |
277 | if (copy_to_user(buf, &fanotify_event_metadata, |
278 | fanotify_event_metadata.event_len)) | |
b2d87909 | 279 | goto out_kill_access_response; |
a1014f10 | 280 | |
7d131623 | 281 | return fanotify_event_metadata.event_len; |
b2d87909 EP |
282 | |
283 | out_kill_access_response: | |
284 | remove_access_response(group, event, fd); | |
285 | out_close_fd: | |
fdbf3cee LS |
286 | if (fd != FAN_NOFD) |
287 | sys_close(fd); | |
ecf6f5e7 EP |
288 | out: |
289 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS | |
290 | if (event->mask & FAN_ALL_PERM_EVENTS) { | |
291 | event->response = FAN_DENY; | |
292 | wake_up(&group->fanotify_data.access_waitq); | |
293 | } | |
294 | #endif | |
b2d87909 | 295 | return ret; |
a1014f10 EP |
296 | } |
297 | ||
298 | /* intofiy userspace file descriptor functions */ | |
299 | static unsigned int fanotify_poll(struct file *file, poll_table *wait) | |
300 | { | |
301 | struct fsnotify_group *group = file->private_data; | |
302 | int ret = 0; | |
303 | ||
304 | poll_wait(file, &group->notification_waitq, wait); | |
305 | mutex_lock(&group->notification_mutex); | |
306 | if (!fsnotify_notify_queue_is_empty(group)) | |
307 | ret = POLLIN | POLLRDNORM; | |
308 | mutex_unlock(&group->notification_mutex); | |
309 | ||
310 | return ret; | |
311 | } | |
312 | ||
313 | static ssize_t fanotify_read(struct file *file, char __user *buf, | |
314 | size_t count, loff_t *pos) | |
315 | { | |
316 | struct fsnotify_group *group; | |
317 | struct fsnotify_event *kevent; | |
318 | char __user *start; | |
319 | int ret; | |
320 | DEFINE_WAIT(wait); | |
321 | ||
322 | start = buf; | |
323 | group = file->private_data; | |
324 | ||
325 | pr_debug("%s: group=%p\n", __func__, group); | |
326 | ||
327 | while (1) { | |
328 | prepare_to_wait(&group->notification_waitq, &wait, TASK_INTERRUPTIBLE); | |
329 | ||
330 | mutex_lock(&group->notification_mutex); | |
331 | kevent = get_one_event(group, count); | |
332 | mutex_unlock(&group->notification_mutex); | |
333 | ||
334 | if (kevent) { | |
335 | ret = PTR_ERR(kevent); | |
336 | if (IS_ERR(kevent)) | |
337 | break; | |
338 | ret = copy_event_to_user(group, kevent, buf); | |
339 | fsnotify_put_event(kevent); | |
340 | if (ret < 0) | |
341 | break; | |
342 | buf += ret; | |
343 | count -= ret; | |
344 | continue; | |
345 | } | |
346 | ||
347 | ret = -EAGAIN; | |
348 | if (file->f_flags & O_NONBLOCK) | |
349 | break; | |
1a5cea72 | 350 | ret = -ERESTARTSYS; |
a1014f10 EP |
351 | if (signal_pending(current)) |
352 | break; | |
353 | ||
354 | if (start != buf) | |
355 | break; | |
356 | ||
357 | schedule(); | |
358 | } | |
359 | ||
360 | finish_wait(&group->notification_waitq, &wait); | |
361 | if (start != buf && ret != -EFAULT) | |
362 | ret = buf - start; | |
363 | return ret; | |
364 | } | |
365 | ||
b2d87909 EP |
366 | static ssize_t fanotify_write(struct file *file, const char __user *buf, size_t count, loff_t *pos) |
367 | { | |
368 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS | |
369 | struct fanotify_response response = { .fd = -1, .response = -1 }; | |
370 | struct fsnotify_group *group; | |
371 | int ret; | |
372 | ||
373 | group = file->private_data; | |
374 | ||
375 | if (count > sizeof(response)) | |
376 | count = sizeof(response); | |
377 | ||
378 | pr_debug("%s: group=%p count=%zu\n", __func__, group, count); | |
379 | ||
380 | if (copy_from_user(&response, buf, count)) | |
381 | return -EFAULT; | |
382 | ||
383 | ret = process_access_response(group, &response); | |
384 | if (ret < 0) | |
385 | count = ret; | |
386 | ||
387 | return count; | |
388 | #else | |
389 | return -EINVAL; | |
390 | #endif | |
391 | } | |
392 | ||
52c923dd EP |
393 | static int fanotify_release(struct inode *ignored, struct file *file) |
394 | { | |
395 | struct fsnotify_group *group = file->private_data; | |
52c923dd | 396 | |
2eebf582 | 397 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
19ba54f4 AM |
398 | struct fanotify_response_event *re, *lre; |
399 | ||
2eebf582 EP |
400 | mutex_lock(&group->fanotify_data.access_mutex); |
401 | ||
09e5f14e | 402 | atomic_inc(&group->fanotify_data.bypass_perm); |
2eebf582 EP |
403 | |
404 | list_for_each_entry_safe(re, lre, &group->fanotify_data.access_list, list) { | |
405 | pr_debug("%s: found group=%p re=%p event=%p\n", __func__, group, | |
406 | re, re->event); | |
407 | ||
408 | list_del_init(&re->list); | |
409 | re->event->response = FAN_ALLOW; | |
410 | ||
411 | kmem_cache_free(fanotify_response_event_cache, re); | |
412 | } | |
413 | mutex_unlock(&group->fanotify_data.access_mutex); | |
414 | ||
415 | wake_up(&group->fanotify_data.access_waitq); | |
416 | #endif | |
52c923dd | 417 | /* matches the fanotify_init->fsnotify_alloc_group */ |
d8153d4d | 418 | fsnotify_destroy_group(group); |
52c923dd EP |
419 | |
420 | return 0; | |
421 | } | |
422 | ||
a1014f10 EP |
423 | static long fanotify_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
424 | { | |
425 | struct fsnotify_group *group; | |
426 | struct fsnotify_event_holder *holder; | |
427 | void __user *p; | |
428 | int ret = -ENOTTY; | |
429 | size_t send_len = 0; | |
430 | ||
431 | group = file->private_data; | |
432 | ||
433 | p = (void __user *) arg; | |
434 | ||
435 | switch (cmd) { | |
436 | case FIONREAD: | |
437 | mutex_lock(&group->notification_mutex); | |
438 | list_for_each_entry(holder, &group->notification_list, event_list) | |
439 | send_len += FAN_EVENT_METADATA_LEN; | |
440 | mutex_unlock(&group->notification_mutex); | |
441 | ret = put_user(send_len, (int __user *) p); | |
442 | break; | |
443 | } | |
444 | ||
445 | return ret; | |
446 | } | |
447 | ||
52c923dd | 448 | static const struct file_operations fanotify_fops = { |
a1014f10 EP |
449 | .poll = fanotify_poll, |
450 | .read = fanotify_read, | |
b2d87909 | 451 | .write = fanotify_write, |
52c923dd EP |
452 | .fasync = NULL, |
453 | .release = fanotify_release, | |
a1014f10 EP |
454 | .unlocked_ioctl = fanotify_ioctl, |
455 | .compat_ioctl = fanotify_ioctl, | |
6038f373 | 456 | .llseek = noop_llseek, |
52c923dd EP |
457 | }; |
458 | ||
2a3edf86 EP |
459 | static void fanotify_free_mark(struct fsnotify_mark *fsn_mark) |
460 | { | |
461 | kmem_cache_free(fanotify_mark_cache, fsn_mark); | |
462 | } | |
463 | ||
464 | static int fanotify_find_path(int dfd, const char __user *filename, | |
465 | struct path *path, unsigned int flags) | |
466 | { | |
467 | int ret; | |
468 | ||
469 | pr_debug("%s: dfd=%d filename=%p flags=%x\n", __func__, | |
470 | dfd, filename, flags); | |
471 | ||
472 | if (filename == NULL) { | |
473 | struct file *file; | |
474 | int fput_needed; | |
475 | ||
476 | ret = -EBADF; | |
477 | file = fget_light(dfd, &fput_needed); | |
478 | if (!file) | |
479 | goto out; | |
480 | ||
481 | ret = -ENOTDIR; | |
482 | if ((flags & FAN_MARK_ONLYDIR) && | |
483 | !(S_ISDIR(file->f_path.dentry->d_inode->i_mode))) { | |
484 | fput_light(file, fput_needed); | |
485 | goto out; | |
486 | } | |
487 | ||
488 | *path = file->f_path; | |
489 | path_get(path); | |
490 | fput_light(file, fput_needed); | |
491 | } else { | |
492 | unsigned int lookup_flags = 0; | |
493 | ||
494 | if (!(flags & FAN_MARK_DONT_FOLLOW)) | |
495 | lookup_flags |= LOOKUP_FOLLOW; | |
496 | if (flags & FAN_MARK_ONLYDIR) | |
497 | lookup_flags |= LOOKUP_DIRECTORY; | |
498 | ||
499 | ret = user_path_at(dfd, filename, lookup_flags, path); | |
500 | if (ret) | |
501 | goto out; | |
502 | } | |
503 | ||
504 | /* you can only watch an inode if you have read permissions on it */ | |
505 | ret = inode_permission(path->dentry->d_inode, MAY_READ); | |
506 | if (ret) | |
507 | path_put(path); | |
508 | out: | |
509 | return ret; | |
510 | } | |
511 | ||
b9e4e3bd EP |
512 | static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark, |
513 | __u32 mask, | |
6dfbd149 LS |
514 | unsigned int flags, |
515 | int *destroy) | |
088b09b0 AG |
516 | { |
517 | __u32 oldmask; | |
518 | ||
519 | spin_lock(&fsn_mark->lock); | |
b9e4e3bd EP |
520 | if (!(flags & FAN_MARK_IGNORED_MASK)) { |
521 | oldmask = fsn_mark->mask; | |
522 | fsnotify_set_mark_mask_locked(fsn_mark, (oldmask & ~mask)); | |
523 | } else { | |
524 | oldmask = fsn_mark->ignored_mask; | |
525 | fsnotify_set_mark_ignored_mask_locked(fsn_mark, (oldmask & ~mask)); | |
526 | } | |
088b09b0 AG |
527 | spin_unlock(&fsn_mark->lock); |
528 | ||
6dfbd149 | 529 | *destroy = !(oldmask & ~mask); |
088b09b0 AG |
530 | |
531 | return mask & oldmask; | |
532 | } | |
533 | ||
f3640192 | 534 | static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group, |
b9e4e3bd EP |
535 | struct vfsmount *mnt, __u32 mask, |
536 | unsigned int flags) | |
88826276 EP |
537 | { |
538 | struct fsnotify_mark *fsn_mark = NULL; | |
088b09b0 | 539 | __u32 removed; |
6dfbd149 | 540 | int destroy_mark; |
88826276 | 541 | |
f3640192 AG |
542 | fsn_mark = fsnotify_find_vfsmount_mark(group, mnt); |
543 | if (!fsn_mark) | |
544 | return -ENOENT; | |
88826276 | 545 | |
6dfbd149 LS |
546 | removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags, |
547 | &destroy_mark); | |
548 | if (destroy_mark) | |
e2a29943 | 549 | fsnotify_destroy_mark(fsn_mark, group); |
6dfbd149 | 550 | |
f3640192 | 551 | fsnotify_put_mark(fsn_mark); |
c63181e6 | 552 | if (removed & real_mount(mnt)->mnt_fsnotify_mask) |
f3640192 AG |
553 | fsnotify_recalc_vfsmount_mask(mnt); |
554 | ||
555 | return 0; | |
556 | } | |
2a3edf86 | 557 | |
f3640192 | 558 | static int fanotify_remove_inode_mark(struct fsnotify_group *group, |
b9e4e3bd EP |
559 | struct inode *inode, __u32 mask, |
560 | unsigned int flags) | |
f3640192 AG |
561 | { |
562 | struct fsnotify_mark *fsn_mark = NULL; | |
563 | __u32 removed; | |
6dfbd149 | 564 | int destroy_mark; |
f3640192 AG |
565 | |
566 | fsn_mark = fsnotify_find_inode_mark(group, inode); | |
88826276 EP |
567 | if (!fsn_mark) |
568 | return -ENOENT; | |
569 | ||
6dfbd149 LS |
570 | removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags, |
571 | &destroy_mark); | |
572 | if (destroy_mark) | |
e2a29943 | 573 | fsnotify_destroy_mark(fsn_mark, group); |
5444e298 | 574 | /* matches the fsnotify_find_inode_mark() */ |
2a3edf86 | 575 | fsnotify_put_mark(fsn_mark); |
f3640192 AG |
576 | if (removed & inode->i_fsnotify_mask) |
577 | fsnotify_recalc_inode_mask(inode); | |
088b09b0 | 578 | |
2a3edf86 EP |
579 | return 0; |
580 | } | |
581 | ||
b9e4e3bd EP |
582 | static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark, |
583 | __u32 mask, | |
584 | unsigned int flags) | |
912ee394 | 585 | { |
192ca4d1 | 586 | __u32 oldmask = -1; |
912ee394 AG |
587 | |
588 | spin_lock(&fsn_mark->lock); | |
b9e4e3bd EP |
589 | if (!(flags & FAN_MARK_IGNORED_MASK)) { |
590 | oldmask = fsn_mark->mask; | |
591 | fsnotify_set_mark_mask_locked(fsn_mark, (oldmask | mask)); | |
592 | } else { | |
192ca4d1 EP |
593 | __u32 tmask = fsn_mark->ignored_mask | mask; |
594 | fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask); | |
c9778a98 EP |
595 | if (flags & FAN_MARK_IGNORED_SURV_MODIFY) |
596 | fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY; | |
b9e4e3bd | 597 | } |
8fcd6528 EP |
598 | |
599 | if (!(flags & FAN_MARK_ONDIR)) { | |
600 | __u32 tmask = fsn_mark->ignored_mask | FAN_ONDIR; | |
601 | fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask); | |
602 | } | |
603 | ||
912ee394 AG |
604 | spin_unlock(&fsn_mark->lock); |
605 | ||
606 | return mask & ~oldmask; | |
607 | } | |
608 | ||
52202dfb | 609 | static int fanotify_add_vfsmount_mark(struct fsnotify_group *group, |
b9e4e3bd EP |
610 | struct vfsmount *mnt, __u32 mask, |
611 | unsigned int flags) | |
2a3edf86 EP |
612 | { |
613 | struct fsnotify_mark *fsn_mark; | |
912ee394 | 614 | __u32 added; |
fa218ab9 | 615 | int ret = 0; |
2a3edf86 | 616 | |
88826276 EP |
617 | fsn_mark = fsnotify_find_vfsmount_mark(group, mnt); |
618 | if (!fsn_mark) { | |
e7099d8a EP |
619 | if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks) |
620 | return -ENOSPC; | |
621 | ||
912ee394 AG |
622 | fsn_mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL); |
623 | if (!fsn_mark) | |
52202dfb | 624 | return -ENOMEM; |
88826276 | 625 | |
912ee394 AG |
626 | fsnotify_init_mark(fsn_mark, fanotify_free_mark); |
627 | ret = fsnotify_add_mark(fsn_mark, group, NULL, mnt, 0); | |
fa218ab9 LS |
628 | if (ret) |
629 | goto err; | |
88826276 | 630 | } |
b9e4e3bd | 631 | added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); |
fa218ab9 | 632 | |
c63181e6 | 633 | if (added & ~real_mount(mnt)->mnt_fsnotify_mask) |
43709a28 | 634 | fsnotify_recalc_vfsmount_mask(mnt); |
fa218ab9 LS |
635 | err: |
636 | fsnotify_put_mark(fsn_mark); | |
637 | return ret; | |
88826276 EP |
638 | } |
639 | ||
52202dfb | 640 | static int fanotify_add_inode_mark(struct fsnotify_group *group, |
b9e4e3bd EP |
641 | struct inode *inode, __u32 mask, |
642 | unsigned int flags) | |
88826276 EP |
643 | { |
644 | struct fsnotify_mark *fsn_mark; | |
912ee394 | 645 | __u32 added; |
fa218ab9 | 646 | int ret = 0; |
88826276 EP |
647 | |
648 | pr_debug("%s: group=%p inode=%p\n", __func__, group, inode); | |
2a3edf86 | 649 | |
5322a59f EP |
650 | /* |
651 | * If some other task has this inode open for write we should not add | |
652 | * an ignored mark, unless that ignored mark is supposed to survive | |
653 | * modification changes anyway. | |
654 | */ | |
655 | if ((flags & FAN_MARK_IGNORED_MASK) && | |
656 | !(flags & FAN_MARK_IGNORED_SURV_MODIFY) && | |
657 | (atomic_read(&inode->i_writecount) > 0)) | |
658 | return 0; | |
659 | ||
5444e298 | 660 | fsn_mark = fsnotify_find_inode_mark(group, inode); |
2a3edf86 | 661 | if (!fsn_mark) { |
e7099d8a EP |
662 | if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks) |
663 | return -ENOSPC; | |
664 | ||
912ee394 AG |
665 | fsn_mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL); |
666 | if (!fsn_mark) | |
52202dfb | 667 | return -ENOMEM; |
2a3edf86 | 668 | |
912ee394 AG |
669 | fsnotify_init_mark(fsn_mark, fanotify_free_mark); |
670 | ret = fsnotify_add_mark(fsn_mark, group, inode, NULL, 0); | |
fa218ab9 LS |
671 | if (ret) |
672 | goto err; | |
2a3edf86 | 673 | } |
b9e4e3bd | 674 | added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); |
fa218ab9 | 675 | |
43709a28 EP |
676 | if (added & ~inode->i_fsnotify_mask) |
677 | fsnotify_recalc_inode_mask(inode); | |
fa218ab9 LS |
678 | err: |
679 | fsnotify_put_mark(fsn_mark); | |
680 | return ret; | |
88826276 | 681 | } |
2a3edf86 | 682 | |
52c923dd | 683 | /* fanotify syscalls */ |
08ae8938 | 684 | SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) |
11637e4b | 685 | { |
52c923dd EP |
686 | struct fsnotify_group *group; |
687 | int f_flags, fd; | |
4afeff85 | 688 | struct user_struct *user; |
52c923dd | 689 | |
08ae8938 EP |
690 | pr_debug("%s: flags=%d event_f_flags=%d\n", |
691 | __func__, flags, event_f_flags); | |
52c923dd | 692 | |
52c923dd | 693 | if (!capable(CAP_SYS_ADMIN)) |
a2f13ad0 | 694 | return -EPERM; |
52c923dd EP |
695 | |
696 | if (flags & ~FAN_ALL_INIT_FLAGS) | |
697 | return -EINVAL; | |
698 | ||
4afeff85 EP |
699 | user = get_current_user(); |
700 | if (atomic_read(&user->fanotify_listeners) > FANOTIFY_DEFAULT_MAX_LISTENERS) { | |
701 | free_uid(user); | |
702 | return -EMFILE; | |
703 | } | |
704 | ||
b2d87909 | 705 | f_flags = O_RDWR | FMODE_NONOTIFY; |
52c923dd EP |
706 | if (flags & FAN_CLOEXEC) |
707 | f_flags |= O_CLOEXEC; | |
708 | if (flags & FAN_NONBLOCK) | |
709 | f_flags |= O_NONBLOCK; | |
710 | ||
711 | /* fsnotify_alloc_group takes a ref. Dropped in fanotify_release */ | |
712 | group = fsnotify_alloc_group(&fanotify_fsnotify_ops); | |
26379198 EP |
713 | if (IS_ERR(group)) { |
714 | free_uid(user); | |
52c923dd | 715 | return PTR_ERR(group); |
26379198 | 716 | } |
52c923dd | 717 | |
4afeff85 EP |
718 | group->fanotify_data.user = user; |
719 | atomic_inc(&user->fanotify_listeners); | |
720 | ||
80af2588 | 721 | group->fanotify_data.f_flags = event_f_flags; |
9e66e423 EP |
722 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
723 | mutex_init(&group->fanotify_data.access_mutex); | |
724 | init_waitqueue_head(&group->fanotify_data.access_waitq); | |
725 | INIT_LIST_HEAD(&group->fanotify_data.access_list); | |
09e5f14e | 726 | atomic_set(&group->fanotify_data.bypass_perm, 0); |
9e66e423 | 727 | #endif |
4231a235 EP |
728 | switch (flags & FAN_ALL_CLASS_BITS) { |
729 | case FAN_CLASS_NOTIF: | |
730 | group->priority = FS_PRIO_0; | |
731 | break; | |
732 | case FAN_CLASS_CONTENT: | |
733 | group->priority = FS_PRIO_1; | |
734 | break; | |
735 | case FAN_CLASS_PRE_CONTENT: | |
736 | group->priority = FS_PRIO_2; | |
737 | break; | |
738 | default: | |
739 | fd = -EINVAL; | |
d8153d4d | 740 | goto out_destroy_group; |
4231a235 | 741 | } |
cb2d429f | 742 | |
5dd03f55 EP |
743 | if (flags & FAN_UNLIMITED_QUEUE) { |
744 | fd = -EPERM; | |
745 | if (!capable(CAP_SYS_ADMIN)) | |
d8153d4d | 746 | goto out_destroy_group; |
5dd03f55 EP |
747 | group->max_events = UINT_MAX; |
748 | } else { | |
749 | group->max_events = FANOTIFY_DEFAULT_MAX_EVENTS; | |
750 | } | |
2529a0df | 751 | |
ac7e22dc EP |
752 | if (flags & FAN_UNLIMITED_MARKS) { |
753 | fd = -EPERM; | |
754 | if (!capable(CAP_SYS_ADMIN)) | |
d8153d4d | 755 | goto out_destroy_group; |
ac7e22dc EP |
756 | group->fanotify_data.max_marks = UINT_MAX; |
757 | } else { | |
758 | group->fanotify_data.max_marks = FANOTIFY_DEFAULT_MAX_MARKS; | |
759 | } | |
e7099d8a | 760 | |
52c923dd EP |
761 | fd = anon_inode_getfd("[fanotify]", &fanotify_fops, group, f_flags); |
762 | if (fd < 0) | |
d8153d4d | 763 | goto out_destroy_group; |
52c923dd EP |
764 | |
765 | return fd; | |
766 | ||
d8153d4d LS |
767 | out_destroy_group: |
768 | fsnotify_destroy_group(group); | |
52c923dd | 769 | return fd; |
11637e4b | 770 | } |
bbaa4168 | 771 | |
9bbfc964 HC |
772 | SYSCALL_DEFINE(fanotify_mark)(int fanotify_fd, unsigned int flags, |
773 | __u64 mask, int dfd, | |
774 | const char __user * pathname) | |
bbaa4168 | 775 | { |
0ff21db9 EP |
776 | struct inode *inode = NULL; |
777 | struct vfsmount *mnt = NULL; | |
2a3edf86 EP |
778 | struct fsnotify_group *group; |
779 | struct file *filp; | |
780 | struct path path; | |
781 | int ret, fput_needed; | |
782 | ||
783 | pr_debug("%s: fanotify_fd=%d flags=%x dfd=%d pathname=%p mask=%llx\n", | |
784 | __func__, fanotify_fd, flags, dfd, pathname, mask); | |
785 | ||
786 | /* we only use the lower 32 bits as of right now. */ | |
787 | if (mask & ((__u64)0xffffffff << 32)) | |
788 | return -EINVAL; | |
789 | ||
88380fe6 AG |
790 | if (flags & ~FAN_ALL_MARK_FLAGS) |
791 | return -EINVAL; | |
4d92604c | 792 | switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) { |
1734dee4 | 793 | case FAN_MARK_ADD: /* fallthrough */ |
88380fe6 | 794 | case FAN_MARK_REMOVE: |
1734dee4 LS |
795 | if (!mask) |
796 | return -EINVAL; | |
4d92604c | 797 | case FAN_MARK_FLUSH: |
88380fe6 AG |
798 | break; |
799 | default: | |
800 | return -EINVAL; | |
801 | } | |
8fcd6528 EP |
802 | |
803 | if (mask & FAN_ONDIR) { | |
804 | flags |= FAN_MARK_ONDIR; | |
805 | mask &= ~FAN_ONDIR; | |
806 | } | |
807 | ||
b2d87909 EP |
808 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
809 | if (mask & ~(FAN_ALL_EVENTS | FAN_ALL_PERM_EVENTS | FAN_EVENT_ON_CHILD)) | |
810 | #else | |
88380fe6 | 811 | if (mask & ~(FAN_ALL_EVENTS | FAN_EVENT_ON_CHILD)) |
b2d87909 | 812 | #endif |
2a3edf86 EP |
813 | return -EINVAL; |
814 | ||
815 | filp = fget_light(fanotify_fd, &fput_needed); | |
816 | if (unlikely(!filp)) | |
817 | return -EBADF; | |
818 | ||
819 | /* verify that this is indeed an fanotify instance */ | |
820 | ret = -EINVAL; | |
821 | if (unlikely(filp->f_op != &fanotify_fops)) | |
822 | goto fput_and_out; | |
4231a235 EP |
823 | group = filp->private_data; |
824 | ||
825 | /* | |
826 | * group->priority == FS_PRIO_0 == FAN_CLASS_NOTIF. These are not | |
827 | * allowed to set permissions events. | |
828 | */ | |
829 | ret = -EINVAL; | |
830 | if (mask & FAN_ALL_PERM_EVENTS && | |
831 | group->priority == FS_PRIO_0) | |
832 | goto fput_and_out; | |
2a3edf86 EP |
833 | |
834 | ret = fanotify_find_path(dfd, pathname, &path, flags); | |
835 | if (ret) | |
836 | goto fput_and_out; | |
837 | ||
838 | /* inode held in place by reference to path; group by fget on fd */ | |
eac8e9e8 | 839 | if (!(flags & FAN_MARK_MOUNT)) |
0ff21db9 EP |
840 | inode = path.dentry->d_inode; |
841 | else | |
842 | mnt = path.mnt; | |
2a3edf86 EP |
843 | |
844 | /* create/update an inode mark */ | |
4d92604c | 845 | switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) { |
c6223f46 | 846 | case FAN_MARK_ADD: |
eac8e9e8 | 847 | if (flags & FAN_MARK_MOUNT) |
b9e4e3bd | 848 | ret = fanotify_add_vfsmount_mark(group, mnt, mask, flags); |
0ff21db9 | 849 | else |
b9e4e3bd | 850 | ret = fanotify_add_inode_mark(group, inode, mask, flags); |
c6223f46 AG |
851 | break; |
852 | case FAN_MARK_REMOVE: | |
f3640192 | 853 | if (flags & FAN_MARK_MOUNT) |
b9e4e3bd | 854 | ret = fanotify_remove_vfsmount_mark(group, mnt, mask, flags); |
f3640192 | 855 | else |
b9e4e3bd | 856 | ret = fanotify_remove_inode_mark(group, inode, mask, flags); |
c6223f46 | 857 | break; |
4d92604c EP |
858 | case FAN_MARK_FLUSH: |
859 | if (flags & FAN_MARK_MOUNT) | |
860 | fsnotify_clear_vfsmount_marks_by_group(group); | |
861 | else | |
862 | fsnotify_clear_inode_marks_by_group(group); | |
4d92604c | 863 | break; |
c6223f46 AG |
864 | default: |
865 | ret = -EINVAL; | |
866 | } | |
2a3edf86 EP |
867 | |
868 | path_put(&path); | |
869 | fput_and_out: | |
870 | fput_light(filp, fput_needed); | |
871 | return ret; | |
872 | } | |
873 | ||
9bbfc964 HC |
874 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS |
875 | asmlinkage long SyS_fanotify_mark(long fanotify_fd, long flags, __u64 mask, | |
876 | long dfd, long pathname) | |
877 | { | |
878 | return SYSC_fanotify_mark((int) fanotify_fd, (unsigned int) flags, | |
879 | mask, (int) dfd, | |
880 | (const char __user *) pathname); | |
881 | } | |
882 | SYSCALL_ALIAS(sys_fanotify_mark, SyS_fanotify_mark); | |
883 | #endif | |
884 | ||
2a3edf86 | 885 | /* |
ae0e47f0 | 886 | * fanotify_user_setup - Our initialization function. Note that we cannot return |
2a3edf86 EP |
887 | * error because we have compiled-in VFS hooks. So an (unlikely) failure here |
888 | * must result in panic(). | |
889 | */ | |
890 | static int __init fanotify_user_setup(void) | |
891 | { | |
892 | fanotify_mark_cache = KMEM_CACHE(fsnotify_mark, SLAB_PANIC); | |
b2d87909 EP |
893 | fanotify_response_event_cache = KMEM_CACHE(fanotify_response_event, |
894 | SLAB_PANIC); | |
2a3edf86 EP |
895 | |
896 | return 0; | |
bbaa4168 | 897 | } |
2a3edf86 | 898 | device_initcall(fanotify_user_setup); |