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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 | ||
109 | static 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; | |
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 | ||
b2d87909 EP |
260 | fd = fill_event_metadata(group, &fanotify_event_metadata, event); |
261 | if (fd < 0) | |
262 | return fd; | |
263 | ||
264 | ret = prepare_for_access_response(group, event, fd); | |
265 | if (ret) | |
266 | goto out_close_fd; | |
a1014f10 | 267 | |
b2d87909 | 268 | ret = -EFAULT; |
a1014f10 | 269 | if (copy_to_user(buf, &fanotify_event_metadata, FAN_EVENT_METADATA_LEN)) |
b2d87909 | 270 | goto out_kill_access_response; |
a1014f10 EP |
271 | |
272 | return FAN_EVENT_METADATA_LEN; | |
b2d87909 EP |
273 | |
274 | out_kill_access_response: | |
275 | remove_access_response(group, event, fd); | |
276 | out_close_fd: | |
277 | sys_close(fd); | |
278 | return ret; | |
a1014f10 EP |
279 | } |
280 | ||
281 | /* intofiy userspace file descriptor functions */ | |
282 | static 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 | ||
296 | static 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; | |
333 | ret = -EINTR; | |
334 | 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 | ||
b2d87909 EP |
349 | static 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 | ||
52c923dd EP |
376 | static int fanotify_release(struct inode *ignored, struct file *file) |
377 | { | |
378 | struct fsnotify_group *group = file->private_data; | |
2eebf582 | 379 | struct fanotify_response_event *re, *lre; |
52c923dd EP |
380 | |
381 | pr_debug("%s: file=%p group=%p\n", __func__, file, group); | |
382 | ||
2eebf582 EP |
383 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
384 | mutex_lock(&group->fanotify_data.access_mutex); | |
385 | ||
386 | group->fanotify_data.bypass_perm = true; | |
387 | ||
388 | list_for_each_entry_safe(re, lre, &group->fanotify_data.access_list, list) { | |
389 | pr_debug("%s: found group=%p re=%p event=%p\n", __func__, group, | |
390 | re, re->event); | |
391 | ||
392 | list_del_init(&re->list); | |
393 | re->event->response = FAN_ALLOW; | |
394 | ||
395 | kmem_cache_free(fanotify_response_event_cache, re); | |
396 | } | |
397 | mutex_unlock(&group->fanotify_data.access_mutex); | |
398 | ||
399 | wake_up(&group->fanotify_data.access_waitq); | |
400 | #endif | |
52c923dd EP |
401 | /* matches the fanotify_init->fsnotify_alloc_group */ |
402 | fsnotify_put_group(group); | |
403 | ||
404 | return 0; | |
405 | } | |
406 | ||
a1014f10 EP |
407 | static long fanotify_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
408 | { | |
409 | struct fsnotify_group *group; | |
410 | struct fsnotify_event_holder *holder; | |
411 | void __user *p; | |
412 | int ret = -ENOTTY; | |
413 | size_t send_len = 0; | |
414 | ||
415 | group = file->private_data; | |
416 | ||
417 | p = (void __user *) arg; | |
418 | ||
419 | switch (cmd) { | |
420 | case FIONREAD: | |
421 | mutex_lock(&group->notification_mutex); | |
422 | list_for_each_entry(holder, &group->notification_list, event_list) | |
423 | send_len += FAN_EVENT_METADATA_LEN; | |
424 | mutex_unlock(&group->notification_mutex); | |
425 | ret = put_user(send_len, (int __user *) p); | |
426 | break; | |
427 | } | |
428 | ||
429 | return ret; | |
430 | } | |
431 | ||
52c923dd | 432 | static const struct file_operations fanotify_fops = { |
a1014f10 EP |
433 | .poll = fanotify_poll, |
434 | .read = fanotify_read, | |
b2d87909 | 435 | .write = fanotify_write, |
52c923dd EP |
436 | .fasync = NULL, |
437 | .release = fanotify_release, | |
a1014f10 EP |
438 | .unlocked_ioctl = fanotify_ioctl, |
439 | .compat_ioctl = fanotify_ioctl, | |
6038f373 | 440 | .llseek = noop_llseek, |
52c923dd EP |
441 | }; |
442 | ||
2a3edf86 EP |
443 | static void fanotify_free_mark(struct fsnotify_mark *fsn_mark) |
444 | { | |
445 | kmem_cache_free(fanotify_mark_cache, fsn_mark); | |
446 | } | |
447 | ||
448 | static int fanotify_find_path(int dfd, const char __user *filename, | |
449 | struct path *path, unsigned int flags) | |
450 | { | |
451 | int ret; | |
452 | ||
453 | pr_debug("%s: dfd=%d filename=%p flags=%x\n", __func__, | |
454 | dfd, filename, flags); | |
455 | ||
456 | if (filename == NULL) { | |
457 | struct file *file; | |
458 | int fput_needed; | |
459 | ||
460 | ret = -EBADF; | |
461 | file = fget_light(dfd, &fput_needed); | |
462 | if (!file) | |
463 | goto out; | |
464 | ||
465 | ret = -ENOTDIR; | |
466 | if ((flags & FAN_MARK_ONLYDIR) && | |
467 | !(S_ISDIR(file->f_path.dentry->d_inode->i_mode))) { | |
468 | fput_light(file, fput_needed); | |
469 | goto out; | |
470 | } | |
471 | ||
472 | *path = file->f_path; | |
473 | path_get(path); | |
474 | fput_light(file, fput_needed); | |
475 | } else { | |
476 | unsigned int lookup_flags = 0; | |
477 | ||
478 | if (!(flags & FAN_MARK_DONT_FOLLOW)) | |
479 | lookup_flags |= LOOKUP_FOLLOW; | |
480 | if (flags & FAN_MARK_ONLYDIR) | |
481 | lookup_flags |= LOOKUP_DIRECTORY; | |
482 | ||
483 | ret = user_path_at(dfd, filename, lookup_flags, path); | |
484 | if (ret) | |
485 | goto out; | |
486 | } | |
487 | ||
488 | /* you can only watch an inode if you have read permissions on it */ | |
489 | ret = inode_permission(path->dentry->d_inode, MAY_READ); | |
490 | if (ret) | |
491 | path_put(path); | |
492 | out: | |
493 | return ret; | |
494 | } | |
495 | ||
b9e4e3bd EP |
496 | static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark, |
497 | __u32 mask, | |
498 | unsigned int flags) | |
088b09b0 AG |
499 | { |
500 | __u32 oldmask; | |
501 | ||
502 | spin_lock(&fsn_mark->lock); | |
b9e4e3bd EP |
503 | if (!(flags & FAN_MARK_IGNORED_MASK)) { |
504 | oldmask = fsn_mark->mask; | |
505 | fsnotify_set_mark_mask_locked(fsn_mark, (oldmask & ~mask)); | |
506 | } else { | |
507 | oldmask = fsn_mark->ignored_mask; | |
508 | fsnotify_set_mark_ignored_mask_locked(fsn_mark, (oldmask & ~mask)); | |
509 | } | |
088b09b0 AG |
510 | spin_unlock(&fsn_mark->lock); |
511 | ||
512 | if (!(oldmask & ~mask)) | |
513 | fsnotify_destroy_mark(fsn_mark); | |
514 | ||
515 | return mask & oldmask; | |
516 | } | |
517 | ||
f3640192 | 518 | static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group, |
b9e4e3bd EP |
519 | struct vfsmount *mnt, __u32 mask, |
520 | unsigned int flags) | |
88826276 EP |
521 | { |
522 | struct fsnotify_mark *fsn_mark = NULL; | |
088b09b0 | 523 | __u32 removed; |
88826276 | 524 | |
f3640192 AG |
525 | fsn_mark = fsnotify_find_vfsmount_mark(group, mnt); |
526 | if (!fsn_mark) | |
527 | return -ENOENT; | |
88826276 | 528 | |
b9e4e3bd | 529 | removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags); |
f3640192 | 530 | fsnotify_put_mark(fsn_mark); |
f3640192 AG |
531 | if (removed & mnt->mnt_fsnotify_mask) |
532 | fsnotify_recalc_vfsmount_mask(mnt); | |
533 | ||
534 | return 0; | |
535 | } | |
2a3edf86 | 536 | |
f3640192 | 537 | static int fanotify_remove_inode_mark(struct fsnotify_group *group, |
b9e4e3bd EP |
538 | struct inode *inode, __u32 mask, |
539 | unsigned int flags) | |
f3640192 AG |
540 | { |
541 | struct fsnotify_mark *fsn_mark = NULL; | |
542 | __u32 removed; | |
543 | ||
544 | fsn_mark = fsnotify_find_inode_mark(group, inode); | |
88826276 EP |
545 | if (!fsn_mark) |
546 | return -ENOENT; | |
547 | ||
b9e4e3bd | 548 | removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags); |
5444e298 | 549 | /* matches the fsnotify_find_inode_mark() */ |
2a3edf86 | 550 | fsnotify_put_mark(fsn_mark); |
f3640192 AG |
551 | if (removed & inode->i_fsnotify_mask) |
552 | fsnotify_recalc_inode_mask(inode); | |
088b09b0 | 553 | |
2a3edf86 EP |
554 | return 0; |
555 | } | |
556 | ||
b9e4e3bd EP |
557 | static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark, |
558 | __u32 mask, | |
559 | unsigned int flags) | |
912ee394 | 560 | { |
192ca4d1 | 561 | __u32 oldmask = -1; |
912ee394 AG |
562 | |
563 | spin_lock(&fsn_mark->lock); | |
b9e4e3bd EP |
564 | if (!(flags & FAN_MARK_IGNORED_MASK)) { |
565 | oldmask = fsn_mark->mask; | |
566 | fsnotify_set_mark_mask_locked(fsn_mark, (oldmask | mask)); | |
567 | } else { | |
192ca4d1 EP |
568 | __u32 tmask = fsn_mark->ignored_mask | mask; |
569 | fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask); | |
c9778a98 EP |
570 | if (flags & FAN_MARK_IGNORED_SURV_MODIFY) |
571 | fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY; | |
b9e4e3bd | 572 | } |
8fcd6528 EP |
573 | |
574 | if (!(flags & FAN_MARK_ONDIR)) { | |
575 | __u32 tmask = fsn_mark->ignored_mask | FAN_ONDIR; | |
576 | fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask); | |
577 | } | |
578 | ||
912ee394 AG |
579 | spin_unlock(&fsn_mark->lock); |
580 | ||
581 | return mask & ~oldmask; | |
582 | } | |
583 | ||
52202dfb | 584 | static int fanotify_add_vfsmount_mark(struct fsnotify_group *group, |
b9e4e3bd EP |
585 | struct vfsmount *mnt, __u32 mask, |
586 | unsigned int flags) | |
2a3edf86 EP |
587 | { |
588 | struct fsnotify_mark *fsn_mark; | |
912ee394 | 589 | __u32 added; |
2a3edf86 | 590 | |
88826276 EP |
591 | fsn_mark = fsnotify_find_vfsmount_mark(group, mnt); |
592 | if (!fsn_mark) { | |
88826276 EP |
593 | int ret; |
594 | ||
e7099d8a EP |
595 | if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks) |
596 | return -ENOSPC; | |
597 | ||
912ee394 AG |
598 | fsn_mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL); |
599 | if (!fsn_mark) | |
52202dfb | 600 | return -ENOMEM; |
88826276 | 601 | |
912ee394 AG |
602 | fsnotify_init_mark(fsn_mark, fanotify_free_mark); |
603 | ret = fsnotify_add_mark(fsn_mark, group, NULL, mnt, 0); | |
88826276 | 604 | if (ret) { |
912ee394 | 605 | fanotify_free_mark(fsn_mark); |
52202dfb | 606 | return ret; |
88826276 | 607 | } |
88826276 | 608 | } |
b9e4e3bd | 609 | added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); |
52202dfb | 610 | fsnotify_put_mark(fsn_mark); |
43709a28 EP |
611 | if (added & ~mnt->mnt_fsnotify_mask) |
612 | fsnotify_recalc_vfsmount_mask(mnt); | |
613 | ||
52202dfb | 614 | return 0; |
88826276 EP |
615 | } |
616 | ||
52202dfb | 617 | static int fanotify_add_inode_mark(struct fsnotify_group *group, |
b9e4e3bd EP |
618 | struct inode *inode, __u32 mask, |
619 | unsigned int flags) | |
88826276 EP |
620 | { |
621 | struct fsnotify_mark *fsn_mark; | |
912ee394 | 622 | __u32 added; |
88826276 EP |
623 | |
624 | pr_debug("%s: group=%p inode=%p\n", __func__, group, inode); | |
2a3edf86 | 625 | |
5322a59f EP |
626 | /* |
627 | * If some other task has this inode open for write we should not add | |
628 | * an ignored mark, unless that ignored mark is supposed to survive | |
629 | * modification changes anyway. | |
630 | */ | |
631 | if ((flags & FAN_MARK_IGNORED_MASK) && | |
632 | !(flags & FAN_MARK_IGNORED_SURV_MODIFY) && | |
633 | (atomic_read(&inode->i_writecount) > 0)) | |
634 | return 0; | |
635 | ||
5444e298 | 636 | fsn_mark = fsnotify_find_inode_mark(group, inode); |
2a3edf86 | 637 | if (!fsn_mark) { |
88826276 | 638 | int ret; |
2a3edf86 | 639 | |
e7099d8a EP |
640 | if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks) |
641 | return -ENOSPC; | |
642 | ||
912ee394 AG |
643 | fsn_mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL); |
644 | if (!fsn_mark) | |
52202dfb | 645 | return -ENOMEM; |
2a3edf86 | 646 | |
912ee394 AG |
647 | fsnotify_init_mark(fsn_mark, fanotify_free_mark); |
648 | ret = fsnotify_add_mark(fsn_mark, group, inode, NULL, 0); | |
2a3edf86 | 649 | if (ret) { |
912ee394 | 650 | fanotify_free_mark(fsn_mark); |
52202dfb | 651 | return ret; |
2a3edf86 | 652 | } |
2a3edf86 | 653 | } |
b9e4e3bd | 654 | added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); |
52202dfb | 655 | fsnotify_put_mark(fsn_mark); |
43709a28 EP |
656 | if (added & ~inode->i_fsnotify_mask) |
657 | fsnotify_recalc_inode_mask(inode); | |
52202dfb | 658 | return 0; |
88826276 | 659 | } |
2a3edf86 | 660 | |
52c923dd | 661 | /* fanotify syscalls */ |
08ae8938 | 662 | SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) |
11637e4b | 663 | { |
52c923dd EP |
664 | struct fsnotify_group *group; |
665 | int f_flags, fd; | |
4afeff85 | 666 | struct user_struct *user; |
52c923dd | 667 | |
08ae8938 EP |
668 | pr_debug("%s: flags=%d event_f_flags=%d\n", |
669 | __func__, flags, event_f_flags); | |
52c923dd | 670 | |
52c923dd | 671 | if (!capable(CAP_SYS_ADMIN)) |
a2f13ad0 | 672 | return -EPERM; |
52c923dd EP |
673 | |
674 | if (flags & ~FAN_ALL_INIT_FLAGS) | |
675 | return -EINVAL; | |
676 | ||
4afeff85 EP |
677 | user = get_current_user(); |
678 | if (atomic_read(&user->fanotify_listeners) > FANOTIFY_DEFAULT_MAX_LISTENERS) { | |
679 | free_uid(user); | |
680 | return -EMFILE; | |
681 | } | |
682 | ||
b2d87909 | 683 | f_flags = O_RDWR | FMODE_NONOTIFY; |
52c923dd EP |
684 | if (flags & FAN_CLOEXEC) |
685 | f_flags |= O_CLOEXEC; | |
686 | if (flags & FAN_NONBLOCK) | |
687 | f_flags |= O_NONBLOCK; | |
688 | ||
689 | /* fsnotify_alloc_group takes a ref. Dropped in fanotify_release */ | |
690 | group = fsnotify_alloc_group(&fanotify_fsnotify_ops); | |
691 | if (IS_ERR(group)) | |
692 | return PTR_ERR(group); | |
693 | ||
4afeff85 EP |
694 | group->fanotify_data.user = user; |
695 | atomic_inc(&user->fanotify_listeners); | |
696 | ||
80af2588 | 697 | group->fanotify_data.f_flags = event_f_flags; |
9e66e423 EP |
698 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
699 | mutex_init(&group->fanotify_data.access_mutex); | |
700 | init_waitqueue_head(&group->fanotify_data.access_waitq); | |
701 | INIT_LIST_HEAD(&group->fanotify_data.access_list); | |
702 | #endif | |
4231a235 EP |
703 | switch (flags & FAN_ALL_CLASS_BITS) { |
704 | case FAN_CLASS_NOTIF: | |
705 | group->priority = FS_PRIO_0; | |
706 | break; | |
707 | case FAN_CLASS_CONTENT: | |
708 | group->priority = FS_PRIO_1; | |
709 | break; | |
710 | case FAN_CLASS_PRE_CONTENT: | |
711 | group->priority = FS_PRIO_2; | |
712 | break; | |
713 | default: | |
714 | fd = -EINVAL; | |
715 | goto out_put_group; | |
716 | } | |
cb2d429f | 717 | |
5dd03f55 EP |
718 | if (flags & FAN_UNLIMITED_QUEUE) { |
719 | fd = -EPERM; | |
720 | if (!capable(CAP_SYS_ADMIN)) | |
721 | goto out_put_group; | |
722 | group->max_events = UINT_MAX; | |
723 | } else { | |
724 | group->max_events = FANOTIFY_DEFAULT_MAX_EVENTS; | |
725 | } | |
2529a0df | 726 | |
ac7e22dc EP |
727 | if (flags & FAN_UNLIMITED_MARKS) { |
728 | fd = -EPERM; | |
729 | if (!capable(CAP_SYS_ADMIN)) | |
730 | goto out_put_group; | |
731 | group->fanotify_data.max_marks = UINT_MAX; | |
732 | } else { | |
733 | group->fanotify_data.max_marks = FANOTIFY_DEFAULT_MAX_MARKS; | |
734 | } | |
e7099d8a | 735 | |
52c923dd EP |
736 | fd = anon_inode_getfd("[fanotify]", &fanotify_fops, group, f_flags); |
737 | if (fd < 0) | |
738 | goto out_put_group; | |
739 | ||
740 | return fd; | |
741 | ||
742 | out_put_group: | |
743 | fsnotify_put_group(group); | |
744 | return fd; | |
11637e4b | 745 | } |
bbaa4168 | 746 | |
9bbfc964 HC |
747 | SYSCALL_DEFINE(fanotify_mark)(int fanotify_fd, unsigned int flags, |
748 | __u64 mask, int dfd, | |
749 | const char __user * pathname) | |
bbaa4168 | 750 | { |
0ff21db9 EP |
751 | struct inode *inode = NULL; |
752 | struct vfsmount *mnt = NULL; | |
2a3edf86 EP |
753 | struct fsnotify_group *group; |
754 | struct file *filp; | |
755 | struct path path; | |
756 | int ret, fput_needed; | |
757 | ||
758 | pr_debug("%s: fanotify_fd=%d flags=%x dfd=%d pathname=%p mask=%llx\n", | |
759 | __func__, fanotify_fd, flags, dfd, pathname, mask); | |
760 | ||
761 | /* we only use the lower 32 bits as of right now. */ | |
762 | if (mask & ((__u64)0xffffffff << 32)) | |
763 | return -EINVAL; | |
764 | ||
88380fe6 AG |
765 | if (flags & ~FAN_ALL_MARK_FLAGS) |
766 | return -EINVAL; | |
4d92604c | 767 | switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) { |
88380fe6 AG |
768 | case FAN_MARK_ADD: |
769 | case FAN_MARK_REMOVE: | |
4d92604c | 770 | case FAN_MARK_FLUSH: |
88380fe6 AG |
771 | break; |
772 | default: | |
773 | return -EINVAL; | |
774 | } | |
8fcd6528 EP |
775 | |
776 | if (mask & FAN_ONDIR) { | |
777 | flags |= FAN_MARK_ONDIR; | |
778 | mask &= ~FAN_ONDIR; | |
779 | } | |
780 | ||
b2d87909 EP |
781 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
782 | if (mask & ~(FAN_ALL_EVENTS | FAN_ALL_PERM_EVENTS | FAN_EVENT_ON_CHILD)) | |
783 | #else | |
88380fe6 | 784 | if (mask & ~(FAN_ALL_EVENTS | FAN_EVENT_ON_CHILD)) |
b2d87909 | 785 | #endif |
2a3edf86 EP |
786 | return -EINVAL; |
787 | ||
788 | filp = fget_light(fanotify_fd, &fput_needed); | |
789 | if (unlikely(!filp)) | |
790 | return -EBADF; | |
791 | ||
792 | /* verify that this is indeed an fanotify instance */ | |
793 | ret = -EINVAL; | |
794 | if (unlikely(filp->f_op != &fanotify_fops)) | |
795 | goto fput_and_out; | |
4231a235 EP |
796 | group = filp->private_data; |
797 | ||
798 | /* | |
799 | * group->priority == FS_PRIO_0 == FAN_CLASS_NOTIF. These are not | |
800 | * allowed to set permissions events. | |
801 | */ | |
802 | ret = -EINVAL; | |
803 | if (mask & FAN_ALL_PERM_EVENTS && | |
804 | group->priority == FS_PRIO_0) | |
805 | goto fput_and_out; | |
2a3edf86 EP |
806 | |
807 | ret = fanotify_find_path(dfd, pathname, &path, flags); | |
808 | if (ret) | |
809 | goto fput_and_out; | |
810 | ||
811 | /* inode held in place by reference to path; group by fget on fd */ | |
eac8e9e8 | 812 | if (!(flags & FAN_MARK_MOUNT)) |
0ff21db9 EP |
813 | inode = path.dentry->d_inode; |
814 | else | |
815 | mnt = path.mnt; | |
2a3edf86 EP |
816 | |
817 | /* create/update an inode mark */ | |
4d92604c | 818 | switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) { |
c6223f46 | 819 | case FAN_MARK_ADD: |
eac8e9e8 | 820 | if (flags & FAN_MARK_MOUNT) |
b9e4e3bd | 821 | ret = fanotify_add_vfsmount_mark(group, mnt, mask, flags); |
0ff21db9 | 822 | else |
b9e4e3bd | 823 | ret = fanotify_add_inode_mark(group, inode, mask, flags); |
c6223f46 AG |
824 | break; |
825 | case FAN_MARK_REMOVE: | |
f3640192 | 826 | if (flags & FAN_MARK_MOUNT) |
b9e4e3bd | 827 | ret = fanotify_remove_vfsmount_mark(group, mnt, mask, flags); |
f3640192 | 828 | else |
b9e4e3bd | 829 | ret = fanotify_remove_inode_mark(group, inode, mask, flags); |
c6223f46 | 830 | break; |
4d92604c EP |
831 | case FAN_MARK_FLUSH: |
832 | if (flags & FAN_MARK_MOUNT) | |
833 | fsnotify_clear_vfsmount_marks_by_group(group); | |
834 | else | |
835 | fsnotify_clear_inode_marks_by_group(group); | |
4d92604c | 836 | break; |
c6223f46 AG |
837 | default: |
838 | ret = -EINVAL; | |
839 | } | |
2a3edf86 EP |
840 | |
841 | path_put(&path); | |
842 | fput_and_out: | |
843 | fput_light(filp, fput_needed); | |
844 | return ret; | |
845 | } | |
846 | ||
9bbfc964 HC |
847 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS |
848 | asmlinkage long SyS_fanotify_mark(long fanotify_fd, long flags, __u64 mask, | |
849 | long dfd, long pathname) | |
850 | { | |
851 | return SYSC_fanotify_mark((int) fanotify_fd, (unsigned int) flags, | |
852 | mask, (int) dfd, | |
853 | (const char __user *) pathname); | |
854 | } | |
855 | SYSCALL_ALIAS(sys_fanotify_mark, SyS_fanotify_mark); | |
856 | #endif | |
857 | ||
2a3edf86 EP |
858 | /* |
859 | * fanotify_user_setup - Our initialization function. Note that we cannnot return | |
860 | * error because we have compiled-in VFS hooks. So an (unlikely) failure here | |
861 | * must result in panic(). | |
862 | */ | |
863 | static int __init fanotify_user_setup(void) | |
864 | { | |
865 | fanotify_mark_cache = KMEM_CACHE(fsnotify_mark, SLAB_PANIC); | |
b2d87909 EP |
866 | fanotify_response_event_cache = KMEM_CACHE(fanotify_response_event, |
867 | SLAB_PANIC); | |
2a3edf86 EP |
868 | |
869 | return 0; | |
bbaa4168 | 870 | } |
2a3edf86 | 871 | device_initcall(fanotify_user_setup); |