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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 | |
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 | ||
352e3b24 AV |
61 | static int create_fd(struct fsnotify_group *group, |
62 | struct fsnotify_event *event, | |
63 | struct file **file) | |
a1014f10 EP |
64 | { |
65 | int client_fd; | |
a1014f10 EP |
66 | struct file *new_file; |
67 | ||
22aa425d | 68 | pr_debug("%s: group=%p event=%p\n", __func__, group, event); |
a1014f10 EP |
69 | |
70 | client_fd = get_unused_fd(); | |
71 | if (client_fd < 0) | |
72 | return client_fd; | |
73 | ||
2069601b | 74 | if (event->data_type != FSNOTIFY_EVENT_PATH) { |
a1014f10 EP |
75 | WARN_ON(1); |
76 | put_unused_fd(client_fd); | |
77 | return -EINVAL; | |
78 | } | |
79 | ||
80 | /* | |
81 | * we need a new file handle for the userspace program so it can read even if it was | |
82 | * originally opened O_WRONLY. | |
83 | */ | |
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 */ | |
765927b2 AV |
86 | if (event->path.dentry && event->path.mnt) |
87 | new_file = dentry_open(&event->path, | |
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 { | |
352e3b24 | 103 | *file = new_file; |
a1014f10 EP |
104 | } |
105 | ||
22aa425d | 106 | return client_fd; |
a1014f10 EP |
107 | } |
108 | ||
ecf6f5e7 | 109 | static int fill_event_metadata(struct fsnotify_group *group, |
a1014f10 | 110 | struct fanotify_event_metadata *metadata, |
352e3b24 AV |
111 | struct fsnotify_event *event, |
112 | struct file **file) | |
a1014f10 | 113 | { |
fdbf3cee LS |
114 | int ret = 0; |
115 | ||
a1014f10 EP |
116 | pr_debug("%s: group=%p metadata=%p event=%p\n", __func__, |
117 | group, metadata, event); | |
118 | ||
352e3b24 | 119 | *file = NULL; |
a1014f10 | 120 | metadata->event_len = FAN_EVENT_METADATA_LEN; |
7d131623 | 121 | metadata->metadata_len = FAN_EVENT_METADATA_LEN; |
a1014f10 | 122 | metadata->vers = FANOTIFY_METADATA_VERSION; |
33d3dfff | 123 | metadata->mask = event->mask & FAN_ALL_OUTGOING_EVENTS; |
32c32632 | 124 | metadata->pid = pid_vnr(event->tgid); |
fdbf3cee LS |
125 | if (unlikely(event->mask & FAN_Q_OVERFLOW)) |
126 | metadata->fd = FAN_NOFD; | |
127 | else { | |
352e3b24 | 128 | metadata->fd = create_fd(group, event, file); |
fdbf3cee LS |
129 | if (metadata->fd < 0) |
130 | ret = metadata->fd; | |
131 | } | |
a1014f10 | 132 | |
fdbf3cee | 133 | return ret; |
a1014f10 EP |
134 | } |
135 | ||
b2d87909 EP |
136 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
137 | static struct fanotify_response_event *dequeue_re(struct fsnotify_group *group, | |
138 | __s32 fd) | |
139 | { | |
140 | struct fanotify_response_event *re, *return_re = NULL; | |
141 | ||
142 | mutex_lock(&group->fanotify_data.access_mutex); | |
143 | list_for_each_entry(re, &group->fanotify_data.access_list, list) { | |
144 | if (re->fd != fd) | |
145 | continue; | |
146 | ||
147 | list_del_init(&re->list); | |
148 | return_re = re; | |
149 | break; | |
150 | } | |
151 | mutex_unlock(&group->fanotify_data.access_mutex); | |
152 | ||
153 | pr_debug("%s: found return_re=%p\n", __func__, return_re); | |
154 | ||
155 | return return_re; | |
156 | } | |
157 | ||
158 | static int process_access_response(struct fsnotify_group *group, | |
159 | struct fanotify_response *response_struct) | |
160 | { | |
161 | struct fanotify_response_event *re; | |
162 | __s32 fd = response_struct->fd; | |
163 | __u32 response = response_struct->response; | |
164 | ||
165 | pr_debug("%s: group=%p fd=%d response=%d\n", __func__, group, | |
166 | fd, response); | |
167 | /* | |
168 | * make sure the response is valid, if invalid we do nothing and either | |
25985edc | 169 | * userspace can send a valid response or we will clean it up after the |
b2d87909 EP |
170 | * timeout |
171 | */ | |
172 | switch (response) { | |
173 | case FAN_ALLOW: | |
174 | case FAN_DENY: | |
175 | break; | |
176 | default: | |
177 | return -EINVAL; | |
178 | } | |
179 | ||
180 | if (fd < 0) | |
181 | return -EINVAL; | |
182 | ||
183 | re = dequeue_re(group, fd); | |
184 | if (!re) | |
185 | return -ENOENT; | |
186 | ||
187 | re->event->response = response; | |
188 | ||
189 | wake_up(&group->fanotify_data.access_waitq); | |
190 | ||
191 | kmem_cache_free(fanotify_response_event_cache, re); | |
192 | ||
193 | return 0; | |
194 | } | |
195 | ||
196 | static int prepare_for_access_response(struct fsnotify_group *group, | |
197 | struct fsnotify_event *event, | |
198 | __s32 fd) | |
199 | { | |
200 | struct fanotify_response_event *re; | |
201 | ||
202 | if (!(event->mask & FAN_ALL_PERM_EVENTS)) | |
203 | return 0; | |
204 | ||
205 | re = kmem_cache_alloc(fanotify_response_event_cache, GFP_KERNEL); | |
206 | if (!re) | |
207 | return -ENOMEM; | |
208 | ||
209 | re->event = event; | |
210 | re->fd = fd; | |
211 | ||
212 | mutex_lock(&group->fanotify_data.access_mutex); | |
2eebf582 | 213 | |
09e5f14e | 214 | if (atomic_read(&group->fanotify_data.bypass_perm)) { |
2eebf582 EP |
215 | mutex_unlock(&group->fanotify_data.access_mutex); |
216 | kmem_cache_free(fanotify_response_event_cache, re); | |
217 | event->response = FAN_ALLOW; | |
218 | return 0; | |
219 | } | |
220 | ||
b2d87909 EP |
221 | list_add_tail(&re->list, &group->fanotify_data.access_list); |
222 | mutex_unlock(&group->fanotify_data.access_mutex); | |
223 | ||
224 | return 0; | |
225 | } | |
226 | ||
b2d87909 EP |
227 | #else |
228 | static int prepare_for_access_response(struct fsnotify_group *group, | |
229 | struct fsnotify_event *event, | |
230 | __s32 fd) | |
231 | { | |
232 | return 0; | |
233 | } | |
234 | ||
b2d87909 EP |
235 | #endif |
236 | ||
a1014f10 EP |
237 | static ssize_t copy_event_to_user(struct fsnotify_group *group, |
238 | struct fsnotify_event *event, | |
239 | char __user *buf) | |
240 | { | |
241 | struct fanotify_event_metadata fanotify_event_metadata; | |
352e3b24 | 242 | struct file *f; |
b2d87909 | 243 | int fd, ret; |
a1014f10 EP |
244 | |
245 | pr_debug("%s: group=%p event=%p\n", __func__, group, event); | |
246 | ||
352e3b24 | 247 | ret = fill_event_metadata(group, &fanotify_event_metadata, event, &f); |
ecf6f5e7 EP |
248 | if (ret < 0) |
249 | goto out; | |
b2d87909 | 250 | |
fdbf3cee | 251 | fd = fanotify_event_metadata.fd; |
b2d87909 | 252 | ret = -EFAULT; |
7d131623 EP |
253 | if (copy_to_user(buf, &fanotify_event_metadata, |
254 | fanotify_event_metadata.event_len)) | |
352e3b24 AV |
255 | goto out_close_fd; |
256 | ||
257 | ret = prepare_for_access_response(group, event, fd); | |
258 | if (ret) | |
259 | goto out_close_fd; | |
a1014f10 | 260 | |
3587b1b0 AV |
261 | if (fd != FAN_NOFD) |
262 | fd_install(fd, f); | |
7d131623 | 263 | return fanotify_event_metadata.event_len; |
b2d87909 | 264 | |
b2d87909 | 265 | out_close_fd: |
352e3b24 AV |
266 | if (fd != FAN_NOFD) { |
267 | put_unused_fd(fd); | |
268 | fput(f); | |
269 | } | |
ecf6f5e7 EP |
270 | out: |
271 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS | |
272 | if (event->mask & FAN_ALL_PERM_EVENTS) { | |
273 | event->response = FAN_DENY; | |
274 | wake_up(&group->fanotify_data.access_waitq); | |
275 | } | |
276 | #endif | |
b2d87909 | 277 | return ret; |
a1014f10 EP |
278 | } |
279 | ||
280 | /* intofiy userspace file descriptor functions */ | |
281 | static unsigned int fanotify_poll(struct file *file, poll_table *wait) | |
282 | { | |
283 | struct fsnotify_group *group = file->private_data; | |
284 | int ret = 0; | |
285 | ||
286 | poll_wait(file, &group->notification_waitq, wait); | |
287 | mutex_lock(&group->notification_mutex); | |
288 | if (!fsnotify_notify_queue_is_empty(group)) | |
289 | ret = POLLIN | POLLRDNORM; | |
290 | mutex_unlock(&group->notification_mutex); | |
291 | ||
292 | return ret; | |
293 | } | |
294 | ||
295 | static ssize_t fanotify_read(struct file *file, char __user *buf, | |
296 | size_t count, loff_t *pos) | |
297 | { | |
298 | struct fsnotify_group *group; | |
299 | struct fsnotify_event *kevent; | |
300 | char __user *start; | |
301 | int ret; | |
302 | DEFINE_WAIT(wait); | |
303 | ||
304 | start = buf; | |
305 | group = file->private_data; | |
306 | ||
307 | pr_debug("%s: group=%p\n", __func__, group); | |
308 | ||
309 | while (1) { | |
310 | prepare_to_wait(&group->notification_waitq, &wait, TASK_INTERRUPTIBLE); | |
311 | ||
312 | mutex_lock(&group->notification_mutex); | |
313 | kevent = get_one_event(group, count); | |
314 | mutex_unlock(&group->notification_mutex); | |
315 | ||
316 | if (kevent) { | |
317 | ret = PTR_ERR(kevent); | |
318 | if (IS_ERR(kevent)) | |
319 | break; | |
320 | ret = copy_event_to_user(group, kevent, buf); | |
321 | fsnotify_put_event(kevent); | |
322 | if (ret < 0) | |
323 | break; | |
324 | buf += ret; | |
325 | count -= ret; | |
326 | continue; | |
327 | } | |
328 | ||
329 | ret = -EAGAIN; | |
330 | if (file->f_flags & O_NONBLOCK) | |
331 | break; | |
1a5cea72 | 332 | ret = -ERESTARTSYS; |
a1014f10 EP |
333 | if (signal_pending(current)) |
334 | break; | |
335 | ||
336 | if (start != buf) | |
337 | break; | |
338 | ||
339 | schedule(); | |
340 | } | |
341 | ||
342 | finish_wait(&group->notification_waitq, &wait); | |
343 | if (start != buf && ret != -EFAULT) | |
344 | ret = buf - start; | |
345 | return ret; | |
346 | } | |
347 | ||
b2d87909 EP |
348 | static ssize_t fanotify_write(struct file *file, const char __user *buf, size_t count, loff_t *pos) |
349 | { | |
350 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS | |
351 | struct fanotify_response response = { .fd = -1, .response = -1 }; | |
352 | struct fsnotify_group *group; | |
353 | int ret; | |
354 | ||
355 | group = file->private_data; | |
356 | ||
357 | if (count > sizeof(response)) | |
358 | count = sizeof(response); | |
359 | ||
360 | pr_debug("%s: group=%p count=%zu\n", __func__, group, count); | |
361 | ||
362 | if (copy_from_user(&response, buf, count)) | |
363 | return -EFAULT; | |
364 | ||
365 | ret = process_access_response(group, &response); | |
366 | if (ret < 0) | |
367 | count = ret; | |
368 | ||
369 | return count; | |
370 | #else | |
371 | return -EINVAL; | |
372 | #endif | |
373 | } | |
374 | ||
52c923dd EP |
375 | static int fanotify_release(struct inode *ignored, struct file *file) |
376 | { | |
377 | struct fsnotify_group *group = file->private_data; | |
52c923dd | 378 | |
2eebf582 | 379 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
19ba54f4 AM |
380 | struct fanotify_response_event *re, *lre; |
381 | ||
2eebf582 EP |
382 | mutex_lock(&group->fanotify_data.access_mutex); |
383 | ||
09e5f14e | 384 | atomic_inc(&group->fanotify_data.bypass_perm); |
2eebf582 EP |
385 | |
386 | list_for_each_entry_safe(re, lre, &group->fanotify_data.access_list, list) { | |
387 | pr_debug("%s: found group=%p re=%p event=%p\n", __func__, group, | |
388 | re, re->event); | |
389 | ||
390 | list_del_init(&re->list); | |
391 | re->event->response = FAN_ALLOW; | |
392 | ||
393 | kmem_cache_free(fanotify_response_event_cache, re); | |
394 | } | |
395 | mutex_unlock(&group->fanotify_data.access_mutex); | |
396 | ||
397 | wake_up(&group->fanotify_data.access_waitq); | |
398 | #endif | |
52c923dd EP |
399 | /* matches the fanotify_init->fsnotify_alloc_group */ |
400 | fsnotify_put_group(group); | |
401 | ||
402 | return 0; | |
403 | } | |
404 | ||
a1014f10 EP |
405 | static long fanotify_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
406 | { | |
407 | struct fsnotify_group *group; | |
408 | struct fsnotify_event_holder *holder; | |
409 | void __user *p; | |
410 | int ret = -ENOTTY; | |
411 | size_t send_len = 0; | |
412 | ||
413 | group = file->private_data; | |
414 | ||
415 | p = (void __user *) arg; | |
416 | ||
417 | switch (cmd) { | |
418 | case FIONREAD: | |
419 | mutex_lock(&group->notification_mutex); | |
420 | list_for_each_entry(holder, &group->notification_list, event_list) | |
421 | send_len += FAN_EVENT_METADATA_LEN; | |
422 | mutex_unlock(&group->notification_mutex); | |
423 | ret = put_user(send_len, (int __user *) p); | |
424 | break; | |
425 | } | |
426 | ||
427 | return ret; | |
428 | } | |
429 | ||
52c923dd | 430 | static const struct file_operations fanotify_fops = { |
a1014f10 EP |
431 | .poll = fanotify_poll, |
432 | .read = fanotify_read, | |
b2d87909 | 433 | .write = fanotify_write, |
52c923dd EP |
434 | .fasync = NULL, |
435 | .release = fanotify_release, | |
a1014f10 EP |
436 | .unlocked_ioctl = fanotify_ioctl, |
437 | .compat_ioctl = fanotify_ioctl, | |
6038f373 | 438 | .llseek = noop_llseek, |
52c923dd EP |
439 | }; |
440 | ||
2a3edf86 EP |
441 | static void fanotify_free_mark(struct fsnotify_mark *fsn_mark) |
442 | { | |
443 | kmem_cache_free(fanotify_mark_cache, fsn_mark); | |
444 | } | |
445 | ||
446 | static int fanotify_find_path(int dfd, const char __user *filename, | |
447 | struct path *path, unsigned int flags) | |
448 | { | |
449 | int ret; | |
450 | ||
451 | pr_debug("%s: dfd=%d filename=%p flags=%x\n", __func__, | |
452 | dfd, filename, flags); | |
453 | ||
454 | if (filename == NULL) { | |
2903ff01 | 455 | struct fd f = fdget(dfd); |
2a3edf86 EP |
456 | |
457 | ret = -EBADF; | |
2903ff01 | 458 | if (!f.file) |
2a3edf86 EP |
459 | goto out; |
460 | ||
461 | ret = -ENOTDIR; | |
462 | if ((flags & FAN_MARK_ONLYDIR) && | |
2903ff01 AV |
463 | !(S_ISDIR(f.file->f_path.dentry->d_inode->i_mode))) { |
464 | fdput(f); | |
2a3edf86 EP |
465 | goto out; |
466 | } | |
467 | ||
2903ff01 | 468 | *path = f.file->f_path; |
2a3edf86 | 469 | path_get(path); |
2903ff01 | 470 | fdput(f); |
2a3edf86 EP |
471 | } else { |
472 | unsigned int lookup_flags = 0; | |
473 | ||
474 | if (!(flags & FAN_MARK_DONT_FOLLOW)) | |
475 | lookup_flags |= LOOKUP_FOLLOW; | |
476 | if (flags & FAN_MARK_ONLYDIR) | |
477 | lookup_flags |= LOOKUP_DIRECTORY; | |
478 | ||
479 | ret = user_path_at(dfd, filename, lookup_flags, path); | |
480 | if (ret) | |
481 | goto out; | |
482 | } | |
483 | ||
484 | /* you can only watch an inode if you have read permissions on it */ | |
485 | ret = inode_permission(path->dentry->d_inode, MAY_READ); | |
486 | if (ret) | |
487 | path_put(path); | |
488 | out: | |
489 | return ret; | |
490 | } | |
491 | ||
b9e4e3bd EP |
492 | static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark, |
493 | __u32 mask, | |
494 | unsigned int flags) | |
088b09b0 AG |
495 | { |
496 | __u32 oldmask; | |
497 | ||
498 | spin_lock(&fsn_mark->lock); | |
b9e4e3bd EP |
499 | if (!(flags & FAN_MARK_IGNORED_MASK)) { |
500 | oldmask = fsn_mark->mask; | |
501 | fsnotify_set_mark_mask_locked(fsn_mark, (oldmask & ~mask)); | |
502 | } else { | |
503 | oldmask = fsn_mark->ignored_mask; | |
504 | fsnotify_set_mark_ignored_mask_locked(fsn_mark, (oldmask & ~mask)); | |
505 | } | |
088b09b0 AG |
506 | spin_unlock(&fsn_mark->lock); |
507 | ||
508 | if (!(oldmask & ~mask)) | |
509 | fsnotify_destroy_mark(fsn_mark); | |
510 | ||
511 | return mask & oldmask; | |
512 | } | |
513 | ||
f3640192 | 514 | static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group, |
b9e4e3bd EP |
515 | struct vfsmount *mnt, __u32 mask, |
516 | unsigned int flags) | |
88826276 EP |
517 | { |
518 | struct fsnotify_mark *fsn_mark = NULL; | |
088b09b0 | 519 | __u32 removed; |
88826276 | 520 | |
f3640192 AG |
521 | fsn_mark = fsnotify_find_vfsmount_mark(group, mnt); |
522 | if (!fsn_mark) | |
523 | return -ENOENT; | |
88826276 | 524 | |
b9e4e3bd | 525 | removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags); |
f3640192 | 526 | fsnotify_put_mark(fsn_mark); |
c63181e6 | 527 | if (removed & real_mount(mnt)->mnt_fsnotify_mask) |
f3640192 AG |
528 | fsnotify_recalc_vfsmount_mask(mnt); |
529 | ||
530 | return 0; | |
531 | } | |
2a3edf86 | 532 | |
f3640192 | 533 | static int fanotify_remove_inode_mark(struct fsnotify_group *group, |
b9e4e3bd EP |
534 | struct inode *inode, __u32 mask, |
535 | unsigned int flags) | |
f3640192 AG |
536 | { |
537 | struct fsnotify_mark *fsn_mark = NULL; | |
538 | __u32 removed; | |
539 | ||
540 | fsn_mark = fsnotify_find_inode_mark(group, inode); | |
88826276 EP |
541 | if (!fsn_mark) |
542 | return -ENOENT; | |
543 | ||
b9e4e3bd | 544 | removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags); |
5444e298 | 545 | /* matches the fsnotify_find_inode_mark() */ |
2a3edf86 | 546 | fsnotify_put_mark(fsn_mark); |
f3640192 AG |
547 | if (removed & inode->i_fsnotify_mask) |
548 | fsnotify_recalc_inode_mask(inode); | |
088b09b0 | 549 | |
2a3edf86 EP |
550 | return 0; |
551 | } | |
552 | ||
b9e4e3bd EP |
553 | static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark, |
554 | __u32 mask, | |
555 | unsigned int flags) | |
912ee394 | 556 | { |
192ca4d1 | 557 | __u32 oldmask = -1; |
912ee394 AG |
558 | |
559 | spin_lock(&fsn_mark->lock); | |
b9e4e3bd EP |
560 | if (!(flags & FAN_MARK_IGNORED_MASK)) { |
561 | oldmask = fsn_mark->mask; | |
562 | fsnotify_set_mark_mask_locked(fsn_mark, (oldmask | mask)); | |
563 | } else { | |
192ca4d1 EP |
564 | __u32 tmask = fsn_mark->ignored_mask | mask; |
565 | fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask); | |
c9778a98 EP |
566 | if (flags & FAN_MARK_IGNORED_SURV_MODIFY) |
567 | fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY; | |
b9e4e3bd | 568 | } |
8fcd6528 EP |
569 | |
570 | if (!(flags & FAN_MARK_ONDIR)) { | |
571 | __u32 tmask = fsn_mark->ignored_mask | FAN_ONDIR; | |
572 | fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask); | |
573 | } | |
574 | ||
912ee394 AG |
575 | spin_unlock(&fsn_mark->lock); |
576 | ||
577 | return mask & ~oldmask; | |
578 | } | |
579 | ||
52202dfb | 580 | static int fanotify_add_vfsmount_mark(struct fsnotify_group *group, |
b9e4e3bd EP |
581 | struct vfsmount *mnt, __u32 mask, |
582 | unsigned int flags) | |
2a3edf86 EP |
583 | { |
584 | struct fsnotify_mark *fsn_mark; | |
912ee394 | 585 | __u32 added; |
fa218ab9 | 586 | int ret = 0; |
2a3edf86 | 587 | |
88826276 EP |
588 | fsn_mark = fsnotify_find_vfsmount_mark(group, mnt); |
589 | if (!fsn_mark) { | |
e7099d8a EP |
590 | if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks) |
591 | return -ENOSPC; | |
592 | ||
912ee394 AG |
593 | fsn_mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL); |
594 | if (!fsn_mark) | |
52202dfb | 595 | return -ENOMEM; |
88826276 | 596 | |
912ee394 AG |
597 | fsnotify_init_mark(fsn_mark, fanotify_free_mark); |
598 | ret = fsnotify_add_mark(fsn_mark, group, NULL, mnt, 0); | |
fa218ab9 LS |
599 | if (ret) |
600 | goto err; | |
88826276 | 601 | } |
b9e4e3bd | 602 | added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); |
fa218ab9 | 603 | |
c63181e6 | 604 | if (added & ~real_mount(mnt)->mnt_fsnotify_mask) |
43709a28 | 605 | fsnotify_recalc_vfsmount_mask(mnt); |
fa218ab9 LS |
606 | err: |
607 | fsnotify_put_mark(fsn_mark); | |
608 | return ret; | |
88826276 EP |
609 | } |
610 | ||
52202dfb | 611 | static int fanotify_add_inode_mark(struct fsnotify_group *group, |
b9e4e3bd EP |
612 | struct inode *inode, __u32 mask, |
613 | unsigned int flags) | |
88826276 EP |
614 | { |
615 | struct fsnotify_mark *fsn_mark; | |
912ee394 | 616 | __u32 added; |
fa218ab9 | 617 | int ret = 0; |
88826276 EP |
618 | |
619 | pr_debug("%s: group=%p inode=%p\n", __func__, group, inode); | |
2a3edf86 | 620 | |
5322a59f EP |
621 | /* |
622 | * If some other task has this inode open for write we should not add | |
623 | * an ignored mark, unless that ignored mark is supposed to survive | |
624 | * modification changes anyway. | |
625 | */ | |
626 | if ((flags & FAN_MARK_IGNORED_MASK) && | |
627 | !(flags & FAN_MARK_IGNORED_SURV_MODIFY) && | |
628 | (atomic_read(&inode->i_writecount) > 0)) | |
629 | return 0; | |
630 | ||
5444e298 | 631 | fsn_mark = fsnotify_find_inode_mark(group, inode); |
2a3edf86 | 632 | if (!fsn_mark) { |
e7099d8a EP |
633 | if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks) |
634 | return -ENOSPC; | |
635 | ||
912ee394 AG |
636 | fsn_mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL); |
637 | if (!fsn_mark) | |
52202dfb | 638 | return -ENOMEM; |
2a3edf86 | 639 | |
912ee394 AG |
640 | fsnotify_init_mark(fsn_mark, fanotify_free_mark); |
641 | ret = fsnotify_add_mark(fsn_mark, group, inode, NULL, 0); | |
fa218ab9 LS |
642 | if (ret) |
643 | goto err; | |
2a3edf86 | 644 | } |
b9e4e3bd | 645 | added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); |
fa218ab9 | 646 | |
43709a28 EP |
647 | if (added & ~inode->i_fsnotify_mask) |
648 | fsnotify_recalc_inode_mask(inode); | |
fa218ab9 LS |
649 | err: |
650 | fsnotify_put_mark(fsn_mark); | |
651 | return ret; | |
88826276 | 652 | } |
2a3edf86 | 653 | |
52c923dd | 654 | /* fanotify syscalls */ |
08ae8938 | 655 | SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) |
11637e4b | 656 | { |
52c923dd EP |
657 | struct fsnotify_group *group; |
658 | int f_flags, fd; | |
4afeff85 | 659 | struct user_struct *user; |
52c923dd | 660 | |
08ae8938 EP |
661 | pr_debug("%s: flags=%d event_f_flags=%d\n", |
662 | __func__, flags, event_f_flags); | |
52c923dd | 663 | |
52c923dd | 664 | if (!capable(CAP_SYS_ADMIN)) |
a2f13ad0 | 665 | return -EPERM; |
52c923dd EP |
666 | |
667 | if (flags & ~FAN_ALL_INIT_FLAGS) | |
668 | return -EINVAL; | |
669 | ||
4afeff85 EP |
670 | user = get_current_user(); |
671 | if (atomic_read(&user->fanotify_listeners) > FANOTIFY_DEFAULT_MAX_LISTENERS) { | |
672 | free_uid(user); | |
673 | return -EMFILE; | |
674 | } | |
675 | ||
b2d87909 | 676 | f_flags = O_RDWR | FMODE_NONOTIFY; |
52c923dd EP |
677 | if (flags & FAN_CLOEXEC) |
678 | f_flags |= O_CLOEXEC; | |
679 | if (flags & FAN_NONBLOCK) | |
680 | f_flags |= O_NONBLOCK; | |
681 | ||
682 | /* fsnotify_alloc_group takes a ref. Dropped in fanotify_release */ | |
683 | group = fsnotify_alloc_group(&fanotify_fsnotify_ops); | |
26379198 EP |
684 | if (IS_ERR(group)) { |
685 | free_uid(user); | |
52c923dd | 686 | return PTR_ERR(group); |
26379198 | 687 | } |
52c923dd | 688 | |
4afeff85 EP |
689 | group->fanotify_data.user = user; |
690 | atomic_inc(&user->fanotify_listeners); | |
691 | ||
80af2588 | 692 | group->fanotify_data.f_flags = event_f_flags; |
9e66e423 EP |
693 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
694 | mutex_init(&group->fanotify_data.access_mutex); | |
695 | init_waitqueue_head(&group->fanotify_data.access_waitq); | |
696 | INIT_LIST_HEAD(&group->fanotify_data.access_list); | |
09e5f14e | 697 | atomic_set(&group->fanotify_data.bypass_perm, 0); |
9e66e423 | 698 | #endif |
4231a235 EP |
699 | switch (flags & FAN_ALL_CLASS_BITS) { |
700 | case FAN_CLASS_NOTIF: | |
701 | group->priority = FS_PRIO_0; | |
702 | break; | |
703 | case FAN_CLASS_CONTENT: | |
704 | group->priority = FS_PRIO_1; | |
705 | break; | |
706 | case FAN_CLASS_PRE_CONTENT: | |
707 | group->priority = FS_PRIO_2; | |
708 | break; | |
709 | default: | |
710 | fd = -EINVAL; | |
711 | goto out_put_group; | |
712 | } | |
cb2d429f | 713 | |
5dd03f55 EP |
714 | if (flags & FAN_UNLIMITED_QUEUE) { |
715 | fd = -EPERM; | |
716 | if (!capable(CAP_SYS_ADMIN)) | |
717 | goto out_put_group; | |
718 | group->max_events = UINT_MAX; | |
719 | } else { | |
720 | group->max_events = FANOTIFY_DEFAULT_MAX_EVENTS; | |
721 | } | |
2529a0df | 722 | |
ac7e22dc EP |
723 | if (flags & FAN_UNLIMITED_MARKS) { |
724 | fd = -EPERM; | |
725 | if (!capable(CAP_SYS_ADMIN)) | |
726 | goto out_put_group; | |
727 | group->fanotify_data.max_marks = UINT_MAX; | |
728 | } else { | |
729 | group->fanotify_data.max_marks = FANOTIFY_DEFAULT_MAX_MARKS; | |
730 | } | |
e7099d8a | 731 | |
52c923dd EP |
732 | fd = anon_inode_getfd("[fanotify]", &fanotify_fops, group, f_flags); |
733 | if (fd < 0) | |
734 | goto out_put_group; | |
735 | ||
736 | return fd; | |
737 | ||
738 | out_put_group: | |
739 | fsnotify_put_group(group); | |
740 | return fd; | |
11637e4b | 741 | } |
bbaa4168 | 742 | |
9bbfc964 HC |
743 | SYSCALL_DEFINE(fanotify_mark)(int fanotify_fd, unsigned int flags, |
744 | __u64 mask, int dfd, | |
745 | const char __user * pathname) | |
bbaa4168 | 746 | { |
0ff21db9 EP |
747 | struct inode *inode = NULL; |
748 | struct vfsmount *mnt = NULL; | |
2a3edf86 | 749 | struct fsnotify_group *group; |
2903ff01 | 750 | struct fd f; |
2a3edf86 | 751 | struct path path; |
2903ff01 | 752 | int ret; |
2a3edf86 EP |
753 | |
754 | pr_debug("%s: fanotify_fd=%d flags=%x dfd=%d pathname=%p mask=%llx\n", | |
755 | __func__, fanotify_fd, flags, dfd, pathname, mask); | |
756 | ||
757 | /* we only use the lower 32 bits as of right now. */ | |
758 | if (mask & ((__u64)0xffffffff << 32)) | |
759 | return -EINVAL; | |
760 | ||
88380fe6 AG |
761 | if (flags & ~FAN_ALL_MARK_FLAGS) |
762 | return -EINVAL; | |
4d92604c | 763 | switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) { |
1734dee4 | 764 | case FAN_MARK_ADD: /* fallthrough */ |
88380fe6 | 765 | case FAN_MARK_REMOVE: |
1734dee4 LS |
766 | if (!mask) |
767 | return -EINVAL; | |
4d92604c | 768 | case FAN_MARK_FLUSH: |
88380fe6 AG |
769 | break; |
770 | default: | |
771 | return -EINVAL; | |
772 | } | |
8fcd6528 EP |
773 | |
774 | if (mask & FAN_ONDIR) { | |
775 | flags |= FAN_MARK_ONDIR; | |
776 | mask &= ~FAN_ONDIR; | |
777 | } | |
778 | ||
b2d87909 EP |
779 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
780 | if (mask & ~(FAN_ALL_EVENTS | FAN_ALL_PERM_EVENTS | FAN_EVENT_ON_CHILD)) | |
781 | #else | |
88380fe6 | 782 | if (mask & ~(FAN_ALL_EVENTS | FAN_EVENT_ON_CHILD)) |
b2d87909 | 783 | #endif |
2a3edf86 EP |
784 | return -EINVAL; |
785 | ||
2903ff01 AV |
786 | f = fdget(fanotify_fd); |
787 | if (unlikely(!f.file)) | |
2a3edf86 EP |
788 | return -EBADF; |
789 | ||
790 | /* verify that this is indeed an fanotify instance */ | |
791 | ret = -EINVAL; | |
2903ff01 | 792 | if (unlikely(f.file->f_op != &fanotify_fops)) |
2a3edf86 | 793 | goto fput_and_out; |
2903ff01 | 794 | group = f.file->private_data; |
4231a235 EP |
795 | |
796 | /* | |
797 | * group->priority == FS_PRIO_0 == FAN_CLASS_NOTIF. These are not | |
798 | * allowed to set permissions events. | |
799 | */ | |
800 | ret = -EINVAL; | |
801 | if (mask & FAN_ALL_PERM_EVENTS && | |
802 | group->priority == FS_PRIO_0) | |
803 | goto fput_and_out; | |
2a3edf86 EP |
804 | |
805 | ret = fanotify_find_path(dfd, pathname, &path, flags); | |
806 | if (ret) | |
807 | goto fput_and_out; | |
808 | ||
809 | /* inode held in place by reference to path; group by fget on fd */ | |
eac8e9e8 | 810 | if (!(flags & FAN_MARK_MOUNT)) |
0ff21db9 EP |
811 | inode = path.dentry->d_inode; |
812 | else | |
813 | mnt = path.mnt; | |
2a3edf86 EP |
814 | |
815 | /* create/update an inode mark */ | |
4d92604c | 816 | switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) { |
c6223f46 | 817 | case FAN_MARK_ADD: |
eac8e9e8 | 818 | if (flags & FAN_MARK_MOUNT) |
b9e4e3bd | 819 | ret = fanotify_add_vfsmount_mark(group, mnt, mask, flags); |
0ff21db9 | 820 | else |
b9e4e3bd | 821 | ret = fanotify_add_inode_mark(group, inode, mask, flags); |
c6223f46 AG |
822 | break; |
823 | case FAN_MARK_REMOVE: | |
f3640192 | 824 | if (flags & FAN_MARK_MOUNT) |
b9e4e3bd | 825 | ret = fanotify_remove_vfsmount_mark(group, mnt, mask, flags); |
f3640192 | 826 | else |
b9e4e3bd | 827 | ret = fanotify_remove_inode_mark(group, inode, mask, flags); |
c6223f46 | 828 | break; |
4d92604c EP |
829 | case FAN_MARK_FLUSH: |
830 | if (flags & FAN_MARK_MOUNT) | |
831 | fsnotify_clear_vfsmount_marks_by_group(group); | |
832 | else | |
833 | fsnotify_clear_inode_marks_by_group(group); | |
4d92604c | 834 | break; |
c6223f46 AG |
835 | default: |
836 | ret = -EINVAL; | |
837 | } | |
2a3edf86 EP |
838 | |
839 | path_put(&path); | |
840 | fput_and_out: | |
2903ff01 | 841 | fdput(f); |
2a3edf86 EP |
842 | return ret; |
843 | } | |
844 | ||
9bbfc964 HC |
845 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS |
846 | asmlinkage long SyS_fanotify_mark(long fanotify_fd, long flags, __u64 mask, | |
847 | long dfd, long pathname) | |
848 | { | |
849 | return SYSC_fanotify_mark((int) fanotify_fd, (unsigned int) flags, | |
850 | mask, (int) dfd, | |
851 | (const char __user *) pathname); | |
852 | } | |
853 | SYSCALL_ALIAS(sys_fanotify_mark, SyS_fanotify_mark); | |
854 | #endif | |
855 | ||
2a3edf86 | 856 | /* |
ae0e47f0 | 857 | * fanotify_user_setup - Our initialization function. Note that we cannot return |
2a3edf86 EP |
858 | * error because we have compiled-in VFS hooks. So an (unlikely) failure here |
859 | * must result in panic(). | |
860 | */ | |
861 | static int __init fanotify_user_setup(void) | |
862 | { | |
863 | fanotify_mark_cache = KMEM_CACHE(fsnotify_mark, SLAB_PANIC); | |
b2d87909 EP |
864 | fanotify_response_event_cache = KMEM_CACHE(fanotify_response_event, |
865 | SLAB_PANIC); | |
2a3edf86 EP |
866 | |
867 | return 0; | |
bbaa4168 | 868 | } |
2a3edf86 | 869 | device_initcall(fanotify_user_setup); |