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 | 15 | #include <linux/uaccess.h> |
91c2e0bc | 16 | #include <linux/compat.h> |
a1014f10 EP |
17 | |
18 | #include <asm/ioctls.h> | |
11637e4b | 19 | |
c63181e6 | 20 | #include "../../mount.h" |
be77196b | 21 | #include "../fdinfo.h" |
7053aee2 | 22 | #include "fanotify.h" |
c63181e6 | 23 | |
2529a0df | 24 | #define FANOTIFY_DEFAULT_MAX_EVENTS 16384 |
e7099d8a | 25 | #define FANOTIFY_DEFAULT_MAX_MARKS 8192 |
4afeff85 | 26 | #define FANOTIFY_DEFAULT_MAX_LISTENERS 128 |
2529a0df | 27 | |
48149e9d HS |
28 | /* |
29 | * All flags that may be specified in parameter event_f_flags of fanotify_init. | |
30 | * | |
31 | * Internal and external open flags are stored together in field f_flags of | |
32 | * struct file. Only external open flags shall be allowed in event_f_flags. | |
33 | * Internal flags like FMODE_NONOTIFY, FMODE_EXEC, FMODE_NOCMTIME shall be | |
34 | * excluded. | |
35 | */ | |
36 | #define FANOTIFY_INIT_ALL_EVENT_F_BITS ( \ | |
37 | O_ACCMODE | O_APPEND | O_NONBLOCK | \ | |
38 | __O_SYNC | O_DSYNC | O_CLOEXEC | \ | |
39 | O_LARGEFILE | O_NOATIME ) | |
40 | ||
33d3dfff | 41 | extern const struct fsnotify_ops fanotify_fsnotify_ops; |
11637e4b | 42 | |
2a3edf86 | 43 | static struct kmem_cache *fanotify_mark_cache __read_mostly; |
7053aee2 | 44 | struct kmem_cache *fanotify_event_cachep __read_mostly; |
f083441b | 45 | struct kmem_cache *fanotify_perm_event_cachep __read_mostly; |
2a3edf86 | 46 | |
a1014f10 EP |
47 | /* |
48 | * Get an fsnotify notification event if one exists and is small | |
49 | * enough to fit in "count". Return an error pointer if the count | |
50 | * is not large enough. | |
51 | * | |
52 | * Called with the group->notification_mutex held. | |
53 | */ | |
54 | static struct fsnotify_event *get_one_event(struct fsnotify_group *group, | |
55 | size_t count) | |
56 | { | |
57 | BUG_ON(!mutex_is_locked(&group->notification_mutex)); | |
58 | ||
59 | pr_debug("%s: group=%p count=%zd\n", __func__, group, count); | |
60 | ||
61 | if (fsnotify_notify_queue_is_empty(group)) | |
62 | return NULL; | |
63 | ||
64 | if (FAN_EVENT_METADATA_LEN > count) | |
65 | return ERR_PTR(-EINVAL); | |
66 | ||
67 | /* held the notification_mutex the whole time, so this is the | |
68 | * same event we peeked above */ | |
8ba8fa91 | 69 | return fsnotify_remove_first_event(group); |
a1014f10 EP |
70 | } |
71 | ||
352e3b24 | 72 | static int create_fd(struct fsnotify_group *group, |
7053aee2 JK |
73 | struct fanotify_event_info *event, |
74 | struct file **file) | |
a1014f10 EP |
75 | { |
76 | int client_fd; | |
a1014f10 EP |
77 | struct file *new_file; |
78 | ||
22aa425d | 79 | pr_debug("%s: group=%p event=%p\n", __func__, group, event); |
a1014f10 EP |
80 | |
81 | client_fd = get_unused_fd(); | |
82 | if (client_fd < 0) | |
83 | return client_fd; | |
84 | ||
a1014f10 EP |
85 | /* |
86 | * we need a new file handle for the userspace program so it can read even if it was | |
87 | * originally opened O_WRONLY. | |
88 | */ | |
a1014f10 EP |
89 | /* it's possible this event was an overflow event. in that case dentry and mnt |
90 | * are NULL; That's fine, just don't call dentry open */ | |
765927b2 AV |
91 | if (event->path.dentry && event->path.mnt) |
92 | new_file = dentry_open(&event->path, | |
80af2588 | 93 | group->fanotify_data.f_flags | FMODE_NONOTIFY, |
a1014f10 EP |
94 | current_cred()); |
95 | else | |
96 | new_file = ERR_PTR(-EOVERFLOW); | |
97 | if (IS_ERR(new_file)) { | |
98 | /* | |
99 | * we still send an event even if we can't open the file. this | |
100 | * can happen when say tasks are gone and we try to open their | |
101 | * /proc files or we try to open a WRONLY file like in sysfs | |
102 | * we just send the errno to userspace since there isn't much | |
103 | * else we can do. | |
104 | */ | |
105 | put_unused_fd(client_fd); | |
106 | client_fd = PTR_ERR(new_file); | |
107 | } else { | |
352e3b24 | 108 | *file = new_file; |
a1014f10 EP |
109 | } |
110 | ||
22aa425d | 111 | return client_fd; |
a1014f10 EP |
112 | } |
113 | ||
ecf6f5e7 | 114 | static int fill_event_metadata(struct fsnotify_group *group, |
7053aee2 JK |
115 | struct fanotify_event_metadata *metadata, |
116 | struct fsnotify_event *fsn_event, | |
117 | struct file **file) | |
a1014f10 | 118 | { |
fdbf3cee | 119 | int ret = 0; |
7053aee2 | 120 | struct fanotify_event_info *event; |
fdbf3cee | 121 | |
a1014f10 | 122 | pr_debug("%s: group=%p metadata=%p event=%p\n", __func__, |
7053aee2 | 123 | group, metadata, fsn_event); |
a1014f10 | 124 | |
352e3b24 | 125 | *file = NULL; |
7053aee2 | 126 | event = container_of(fsn_event, struct fanotify_event_info, fse); |
a1014f10 | 127 | metadata->event_len = FAN_EVENT_METADATA_LEN; |
7d131623 | 128 | metadata->metadata_len = FAN_EVENT_METADATA_LEN; |
a1014f10 | 129 | metadata->vers = FANOTIFY_METADATA_VERSION; |
de1e0c40 | 130 | metadata->reserved = 0; |
7053aee2 | 131 | metadata->mask = fsn_event->mask & FAN_ALL_OUTGOING_EVENTS; |
32c32632 | 132 | metadata->pid = pid_vnr(event->tgid); |
7053aee2 | 133 | if (unlikely(fsn_event->mask & FAN_Q_OVERFLOW)) |
fdbf3cee LS |
134 | metadata->fd = FAN_NOFD; |
135 | else { | |
352e3b24 | 136 | metadata->fd = create_fd(group, event, file); |
fdbf3cee LS |
137 | if (metadata->fd < 0) |
138 | ret = metadata->fd; | |
139 | } | |
a1014f10 | 140 | |
fdbf3cee | 141 | return ret; |
a1014f10 EP |
142 | } |
143 | ||
b2d87909 | 144 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
f083441b JK |
145 | static struct fanotify_perm_event_info *dequeue_event( |
146 | struct fsnotify_group *group, int fd) | |
b2d87909 | 147 | { |
f083441b | 148 | struct fanotify_perm_event_info *event, *return_e = NULL; |
b2d87909 | 149 | |
9573f793 | 150 | spin_lock(&group->fanotify_data.access_lock); |
f083441b JK |
151 | list_for_each_entry(event, &group->fanotify_data.access_list, |
152 | fae.fse.list) { | |
153 | if (event->fd != fd) | |
b2d87909 EP |
154 | continue; |
155 | ||
f083441b JK |
156 | list_del_init(&event->fae.fse.list); |
157 | return_e = event; | |
b2d87909 EP |
158 | break; |
159 | } | |
9573f793 | 160 | spin_unlock(&group->fanotify_data.access_lock); |
b2d87909 | 161 | |
f083441b | 162 | pr_debug("%s: found return_re=%p\n", __func__, return_e); |
b2d87909 | 163 | |
f083441b | 164 | return return_e; |
b2d87909 EP |
165 | } |
166 | ||
167 | static int process_access_response(struct fsnotify_group *group, | |
168 | struct fanotify_response *response_struct) | |
169 | { | |
f083441b JK |
170 | struct fanotify_perm_event_info *event; |
171 | int fd = response_struct->fd; | |
172 | int response = response_struct->response; | |
b2d87909 EP |
173 | |
174 | pr_debug("%s: group=%p fd=%d response=%d\n", __func__, group, | |
175 | fd, response); | |
176 | /* | |
177 | * make sure the response is valid, if invalid we do nothing and either | |
25985edc | 178 | * userspace can send a valid response or we will clean it up after the |
b2d87909 EP |
179 | * timeout |
180 | */ | |
181 | switch (response) { | |
182 | case FAN_ALLOW: | |
183 | case FAN_DENY: | |
184 | break; | |
185 | default: | |
186 | return -EINVAL; | |
187 | } | |
188 | ||
189 | if (fd < 0) | |
190 | return -EINVAL; | |
191 | ||
f083441b JK |
192 | event = dequeue_event(group, fd); |
193 | if (!event) | |
b2d87909 EP |
194 | return -ENOENT; |
195 | ||
f083441b | 196 | event->response = response; |
b2d87909 EP |
197 | wake_up(&group->fanotify_data.access_waitq); |
198 | ||
b2d87909 EP |
199 | return 0; |
200 | } | |
b2d87909 EP |
201 | #endif |
202 | ||
a1014f10 EP |
203 | static ssize_t copy_event_to_user(struct fsnotify_group *group, |
204 | struct fsnotify_event *event, | |
205 | char __user *buf) | |
206 | { | |
207 | struct fanotify_event_metadata fanotify_event_metadata; | |
352e3b24 | 208 | struct file *f; |
b2d87909 | 209 | int fd, ret; |
a1014f10 EP |
210 | |
211 | pr_debug("%s: group=%p event=%p\n", __func__, group, event); | |
212 | ||
352e3b24 | 213 | ret = fill_event_metadata(group, &fanotify_event_metadata, event, &f); |
ecf6f5e7 | 214 | if (ret < 0) |
d507816b | 215 | return ret; |
b2d87909 | 216 | |
fdbf3cee | 217 | fd = fanotify_event_metadata.fd; |
b2d87909 | 218 | ret = -EFAULT; |
7d131623 EP |
219 | if (copy_to_user(buf, &fanotify_event_metadata, |
220 | fanotify_event_metadata.event_len)) | |
352e3b24 AV |
221 | goto out_close_fd; |
222 | ||
f083441b | 223 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
d507816b JK |
224 | if (event->mask & FAN_ALL_PERM_EVENTS) |
225 | FANOTIFY_PE(event)->fd = fd; | |
f083441b | 226 | #endif |
a1014f10 | 227 | |
3587b1b0 AV |
228 | if (fd != FAN_NOFD) |
229 | fd_install(fd, f); | |
7d131623 | 230 | return fanotify_event_metadata.event_len; |
b2d87909 | 231 | |
b2d87909 | 232 | out_close_fd: |
352e3b24 AV |
233 | if (fd != FAN_NOFD) { |
234 | put_unused_fd(fd); | |
235 | fput(f); | |
236 | } | |
b2d87909 | 237 | return ret; |
a1014f10 EP |
238 | } |
239 | ||
240 | /* intofiy userspace file descriptor functions */ | |
241 | static unsigned int fanotify_poll(struct file *file, poll_table *wait) | |
242 | { | |
243 | struct fsnotify_group *group = file->private_data; | |
244 | int ret = 0; | |
245 | ||
246 | poll_wait(file, &group->notification_waitq, wait); | |
247 | mutex_lock(&group->notification_mutex); | |
248 | if (!fsnotify_notify_queue_is_empty(group)) | |
249 | ret = POLLIN | POLLRDNORM; | |
250 | mutex_unlock(&group->notification_mutex); | |
251 | ||
252 | return ret; | |
253 | } | |
254 | ||
255 | static ssize_t fanotify_read(struct file *file, char __user *buf, | |
256 | size_t count, loff_t *pos) | |
257 | { | |
258 | struct fsnotify_group *group; | |
259 | struct fsnotify_event *kevent; | |
260 | char __user *start; | |
261 | int ret; | |
262 | DEFINE_WAIT(wait); | |
263 | ||
264 | start = buf; | |
265 | group = file->private_data; | |
266 | ||
267 | pr_debug("%s: group=%p\n", __func__, group); | |
268 | ||
269 | while (1) { | |
270 | prepare_to_wait(&group->notification_waitq, &wait, TASK_INTERRUPTIBLE); | |
271 | ||
272 | mutex_lock(&group->notification_mutex); | |
273 | kevent = get_one_event(group, count); | |
274 | mutex_unlock(&group->notification_mutex); | |
275 | ||
d8aaab4f | 276 | if (IS_ERR(kevent)) { |
a1014f10 | 277 | ret = PTR_ERR(kevent); |
d8aaab4f JK |
278 | break; |
279 | } | |
280 | ||
281 | if (!kevent) { | |
282 | ret = -EAGAIN; | |
283 | if (file->f_flags & O_NONBLOCK) | |
a1014f10 | 284 | break; |
d8aaab4f JK |
285 | |
286 | ret = -ERESTARTSYS; | |
287 | if (signal_pending(current)) | |
288 | break; | |
289 | ||
290 | if (start != buf) | |
a1014f10 | 291 | break; |
d8aaab4f | 292 | schedule(); |
a1014f10 EP |
293 | continue; |
294 | } | |
295 | ||
d8aaab4f JK |
296 | ret = copy_event_to_user(group, kevent, buf); |
297 | /* | |
298 | * Permission events get queued to wait for response. Other | |
299 | * events can be destroyed now. | |
300 | */ | |
d507816b | 301 | if (!(kevent->mask & FAN_ALL_PERM_EVENTS)) { |
d8aaab4f | 302 | fsnotify_destroy_event(group, kevent); |
d507816b JK |
303 | if (ret < 0) |
304 | break; | |
305 | } else { | |
306 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS | |
307 | if (ret < 0) { | |
308 | FANOTIFY_PE(kevent)->response = FAN_DENY; | |
309 | wake_up(&group->fanotify_data.access_waitq); | |
310 | break; | |
311 | } | |
312 | spin_lock(&group->fanotify_data.access_lock); | |
313 | list_add_tail(&kevent->list, | |
314 | &group->fanotify_data.access_list); | |
315 | spin_unlock(&group->fanotify_data.access_lock); | |
316 | #endif | |
317 | } | |
d8aaab4f JK |
318 | buf += ret; |
319 | count -= ret; | |
a1014f10 EP |
320 | } |
321 | ||
322 | finish_wait(&group->notification_waitq, &wait); | |
323 | if (start != buf && ret != -EFAULT) | |
324 | ret = buf - start; | |
325 | return ret; | |
326 | } | |
327 | ||
b2d87909 EP |
328 | static ssize_t fanotify_write(struct file *file, const char __user *buf, size_t count, loff_t *pos) |
329 | { | |
330 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS | |
331 | struct fanotify_response response = { .fd = -1, .response = -1 }; | |
332 | struct fsnotify_group *group; | |
333 | int ret; | |
334 | ||
335 | group = file->private_data; | |
336 | ||
337 | if (count > sizeof(response)) | |
338 | count = sizeof(response); | |
339 | ||
340 | pr_debug("%s: group=%p count=%zu\n", __func__, group, count); | |
341 | ||
342 | if (copy_from_user(&response, buf, count)) | |
343 | return -EFAULT; | |
344 | ||
345 | ret = process_access_response(group, &response); | |
346 | if (ret < 0) | |
347 | count = ret; | |
348 | ||
349 | return count; | |
350 | #else | |
351 | return -EINVAL; | |
352 | #endif | |
353 | } | |
354 | ||
52c923dd EP |
355 | static int fanotify_release(struct inode *ignored, struct file *file) |
356 | { | |
357 | struct fsnotify_group *group = file->private_data; | |
52c923dd | 358 | |
2eebf582 | 359 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
f083441b | 360 | struct fanotify_perm_event_info *event, *next; |
19ba54f4 | 361 | |
5838d444 JK |
362 | /* |
363 | * There may be still new events arriving in the notification queue | |
364 | * but since userspace cannot use fanotify fd anymore, no event can | |
365 | * enter or leave access_list by now. | |
366 | */ | |
9573f793 | 367 | spin_lock(&group->fanotify_data.access_lock); |
2eebf582 | 368 | |
09e5f14e | 369 | atomic_inc(&group->fanotify_data.bypass_perm); |
2eebf582 | 370 | |
f083441b JK |
371 | list_for_each_entry_safe(event, next, &group->fanotify_data.access_list, |
372 | fae.fse.list) { | |
373 | pr_debug("%s: found group=%p event=%p\n", __func__, group, | |
374 | event); | |
2eebf582 | 375 | |
f083441b JK |
376 | list_del_init(&event->fae.fse.list); |
377 | event->response = FAN_ALLOW; | |
2eebf582 | 378 | } |
9573f793 | 379 | spin_unlock(&group->fanotify_data.access_lock); |
2eebf582 | 380 | |
5838d444 JK |
381 | /* |
382 | * Since bypass_perm is set, newly queued events will not wait for | |
383 | * access response. Wake up the already sleeping ones now. | |
384 | * synchronize_srcu() in fsnotify_destroy_group() will wait for all | |
385 | * processes sleeping in fanotify_handle_event() waiting for access | |
386 | * response and thus also for all permission events to be freed. | |
387 | */ | |
2eebf582 EP |
388 | wake_up(&group->fanotify_data.access_waitq); |
389 | #endif | |
0a6b6bd5 | 390 | |
52c923dd | 391 | /* matches the fanotify_init->fsnotify_alloc_group */ |
d8153d4d | 392 | fsnotify_destroy_group(group); |
52c923dd EP |
393 | |
394 | return 0; | |
395 | } | |
396 | ||
a1014f10 EP |
397 | static long fanotify_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
398 | { | |
399 | struct fsnotify_group *group; | |
7053aee2 | 400 | struct fsnotify_event *fsn_event; |
a1014f10 EP |
401 | void __user *p; |
402 | int ret = -ENOTTY; | |
403 | size_t send_len = 0; | |
404 | ||
405 | group = file->private_data; | |
406 | ||
407 | p = (void __user *) arg; | |
408 | ||
409 | switch (cmd) { | |
410 | case FIONREAD: | |
411 | mutex_lock(&group->notification_mutex); | |
7053aee2 | 412 | list_for_each_entry(fsn_event, &group->notification_list, list) |
a1014f10 EP |
413 | send_len += FAN_EVENT_METADATA_LEN; |
414 | mutex_unlock(&group->notification_mutex); | |
415 | ret = put_user(send_len, (int __user *) p); | |
416 | break; | |
417 | } | |
418 | ||
419 | return ret; | |
420 | } | |
421 | ||
52c923dd | 422 | static const struct file_operations fanotify_fops = { |
be77196b | 423 | .show_fdinfo = fanotify_show_fdinfo, |
a1014f10 EP |
424 | .poll = fanotify_poll, |
425 | .read = fanotify_read, | |
b2d87909 | 426 | .write = fanotify_write, |
52c923dd EP |
427 | .fasync = NULL, |
428 | .release = fanotify_release, | |
a1014f10 EP |
429 | .unlocked_ioctl = fanotify_ioctl, |
430 | .compat_ioctl = fanotify_ioctl, | |
6038f373 | 431 | .llseek = noop_llseek, |
52c923dd EP |
432 | }; |
433 | ||
2a3edf86 EP |
434 | static void fanotify_free_mark(struct fsnotify_mark *fsn_mark) |
435 | { | |
436 | kmem_cache_free(fanotify_mark_cache, fsn_mark); | |
437 | } | |
438 | ||
439 | static int fanotify_find_path(int dfd, const char __user *filename, | |
440 | struct path *path, unsigned int flags) | |
441 | { | |
442 | int ret; | |
443 | ||
444 | pr_debug("%s: dfd=%d filename=%p flags=%x\n", __func__, | |
445 | dfd, filename, flags); | |
446 | ||
447 | if (filename == NULL) { | |
2903ff01 | 448 | struct fd f = fdget(dfd); |
2a3edf86 EP |
449 | |
450 | ret = -EBADF; | |
2903ff01 | 451 | if (!f.file) |
2a3edf86 EP |
452 | goto out; |
453 | ||
454 | ret = -ENOTDIR; | |
455 | if ((flags & FAN_MARK_ONLYDIR) && | |
496ad9aa | 456 | !(S_ISDIR(file_inode(f.file)->i_mode))) { |
2903ff01 | 457 | fdput(f); |
2a3edf86 EP |
458 | goto out; |
459 | } | |
460 | ||
2903ff01 | 461 | *path = f.file->f_path; |
2a3edf86 | 462 | path_get(path); |
2903ff01 | 463 | fdput(f); |
2a3edf86 EP |
464 | } else { |
465 | unsigned int lookup_flags = 0; | |
466 | ||
467 | if (!(flags & FAN_MARK_DONT_FOLLOW)) | |
468 | lookup_flags |= LOOKUP_FOLLOW; | |
469 | if (flags & FAN_MARK_ONLYDIR) | |
470 | lookup_flags |= LOOKUP_DIRECTORY; | |
471 | ||
472 | ret = user_path_at(dfd, filename, lookup_flags, path); | |
473 | if (ret) | |
474 | goto out; | |
475 | } | |
476 | ||
477 | /* you can only watch an inode if you have read permissions on it */ | |
478 | ret = inode_permission(path->dentry->d_inode, MAY_READ); | |
479 | if (ret) | |
480 | path_put(path); | |
481 | out: | |
482 | return ret; | |
483 | } | |
484 | ||
b9e4e3bd EP |
485 | static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark, |
486 | __u32 mask, | |
6dfbd149 LS |
487 | unsigned int flags, |
488 | int *destroy) | |
088b09b0 AG |
489 | { |
490 | __u32 oldmask; | |
491 | ||
492 | spin_lock(&fsn_mark->lock); | |
b9e4e3bd EP |
493 | if (!(flags & FAN_MARK_IGNORED_MASK)) { |
494 | oldmask = fsn_mark->mask; | |
495 | fsnotify_set_mark_mask_locked(fsn_mark, (oldmask & ~mask)); | |
496 | } else { | |
497 | oldmask = fsn_mark->ignored_mask; | |
498 | fsnotify_set_mark_ignored_mask_locked(fsn_mark, (oldmask & ~mask)); | |
499 | } | |
088b09b0 AG |
500 | spin_unlock(&fsn_mark->lock); |
501 | ||
6dfbd149 | 502 | *destroy = !(oldmask & ~mask); |
088b09b0 AG |
503 | |
504 | return mask & oldmask; | |
505 | } | |
506 | ||
f3640192 | 507 | static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group, |
b9e4e3bd EP |
508 | struct vfsmount *mnt, __u32 mask, |
509 | unsigned int flags) | |
88826276 EP |
510 | { |
511 | struct fsnotify_mark *fsn_mark = NULL; | |
088b09b0 | 512 | __u32 removed; |
6dfbd149 | 513 | int destroy_mark; |
88826276 | 514 | |
7b18527c | 515 | mutex_lock(&group->mark_mutex); |
f3640192 | 516 | fsn_mark = fsnotify_find_vfsmount_mark(group, mnt); |
7b18527c LS |
517 | if (!fsn_mark) { |
518 | mutex_unlock(&group->mark_mutex); | |
f3640192 | 519 | return -ENOENT; |
7b18527c | 520 | } |
88826276 | 521 | |
6dfbd149 LS |
522 | removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags, |
523 | &destroy_mark); | |
524 | if (destroy_mark) | |
7b18527c LS |
525 | fsnotify_destroy_mark_locked(fsn_mark, group); |
526 | mutex_unlock(&group->mark_mutex); | |
6dfbd149 | 527 | |
f3640192 | 528 | fsnotify_put_mark(fsn_mark); |
c63181e6 | 529 | if (removed & real_mount(mnt)->mnt_fsnotify_mask) |
f3640192 AG |
530 | fsnotify_recalc_vfsmount_mask(mnt); |
531 | ||
532 | return 0; | |
533 | } | |
2a3edf86 | 534 | |
f3640192 | 535 | static int fanotify_remove_inode_mark(struct fsnotify_group *group, |
b9e4e3bd EP |
536 | struct inode *inode, __u32 mask, |
537 | unsigned int flags) | |
f3640192 AG |
538 | { |
539 | struct fsnotify_mark *fsn_mark = NULL; | |
540 | __u32 removed; | |
6dfbd149 | 541 | int destroy_mark; |
f3640192 | 542 | |
7b18527c | 543 | mutex_lock(&group->mark_mutex); |
f3640192 | 544 | fsn_mark = fsnotify_find_inode_mark(group, inode); |
7b18527c LS |
545 | if (!fsn_mark) { |
546 | mutex_unlock(&group->mark_mutex); | |
88826276 | 547 | return -ENOENT; |
7b18527c | 548 | } |
88826276 | 549 | |
6dfbd149 LS |
550 | removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags, |
551 | &destroy_mark); | |
552 | if (destroy_mark) | |
7b18527c LS |
553 | fsnotify_destroy_mark_locked(fsn_mark, group); |
554 | mutex_unlock(&group->mark_mutex); | |
555 | ||
5444e298 | 556 | /* matches the fsnotify_find_inode_mark() */ |
2a3edf86 | 557 | fsnotify_put_mark(fsn_mark); |
f3640192 AG |
558 | if (removed & inode->i_fsnotify_mask) |
559 | fsnotify_recalc_inode_mask(inode); | |
088b09b0 | 560 | |
2a3edf86 EP |
561 | return 0; |
562 | } | |
563 | ||
b9e4e3bd EP |
564 | static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark, |
565 | __u32 mask, | |
566 | unsigned int flags) | |
912ee394 | 567 | { |
192ca4d1 | 568 | __u32 oldmask = -1; |
912ee394 AG |
569 | |
570 | spin_lock(&fsn_mark->lock); | |
b9e4e3bd EP |
571 | if (!(flags & FAN_MARK_IGNORED_MASK)) { |
572 | oldmask = fsn_mark->mask; | |
573 | fsnotify_set_mark_mask_locked(fsn_mark, (oldmask | mask)); | |
574 | } else { | |
192ca4d1 EP |
575 | __u32 tmask = fsn_mark->ignored_mask | mask; |
576 | fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask); | |
c9778a98 EP |
577 | if (flags & FAN_MARK_IGNORED_SURV_MODIFY) |
578 | fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY; | |
b9e4e3bd | 579 | } |
8fcd6528 EP |
580 | |
581 | if (!(flags & FAN_MARK_ONDIR)) { | |
582 | __u32 tmask = fsn_mark->ignored_mask | FAN_ONDIR; | |
583 | fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask); | |
584 | } | |
585 | ||
912ee394 AG |
586 | spin_unlock(&fsn_mark->lock); |
587 | ||
588 | return mask & ~oldmask; | |
589 | } | |
590 | ||
5e9c070c LS |
591 | static struct fsnotify_mark *fanotify_add_new_mark(struct fsnotify_group *group, |
592 | struct inode *inode, | |
593 | struct vfsmount *mnt) | |
594 | { | |
595 | struct fsnotify_mark *mark; | |
596 | int ret; | |
597 | ||
598 | if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks) | |
599 | return ERR_PTR(-ENOSPC); | |
600 | ||
601 | mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL); | |
602 | if (!mark) | |
603 | return ERR_PTR(-ENOMEM); | |
604 | ||
605 | fsnotify_init_mark(mark, fanotify_free_mark); | |
606 | ret = fsnotify_add_mark_locked(mark, group, inode, mnt, 0); | |
607 | if (ret) { | |
608 | fsnotify_put_mark(mark); | |
609 | return ERR_PTR(ret); | |
610 | } | |
611 | ||
612 | return mark; | |
613 | } | |
614 | ||
615 | ||
52202dfb | 616 | static int fanotify_add_vfsmount_mark(struct fsnotify_group *group, |
b9e4e3bd EP |
617 | struct vfsmount *mnt, __u32 mask, |
618 | unsigned int flags) | |
2a3edf86 EP |
619 | { |
620 | struct fsnotify_mark *fsn_mark; | |
912ee394 | 621 | __u32 added; |
2a3edf86 | 622 | |
7b18527c | 623 | mutex_lock(&group->mark_mutex); |
88826276 EP |
624 | fsn_mark = fsnotify_find_vfsmount_mark(group, mnt); |
625 | if (!fsn_mark) { | |
5e9c070c LS |
626 | fsn_mark = fanotify_add_new_mark(group, NULL, mnt); |
627 | if (IS_ERR(fsn_mark)) { | |
7b18527c | 628 | mutex_unlock(&group->mark_mutex); |
5e9c070c | 629 | return PTR_ERR(fsn_mark); |
7b18527c | 630 | } |
88826276 | 631 | } |
b9e4e3bd | 632 | added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); |
7b18527c | 633 | mutex_unlock(&group->mark_mutex); |
fa218ab9 | 634 | |
c63181e6 | 635 | if (added & ~real_mount(mnt)->mnt_fsnotify_mask) |
43709a28 | 636 | fsnotify_recalc_vfsmount_mask(mnt); |
5e9c070c | 637 | |
fa218ab9 | 638 | fsnotify_put_mark(fsn_mark); |
5e9c070c | 639 | return 0; |
88826276 EP |
640 | } |
641 | ||
52202dfb | 642 | static int fanotify_add_inode_mark(struct fsnotify_group *group, |
b9e4e3bd EP |
643 | struct inode *inode, __u32 mask, |
644 | unsigned int flags) | |
88826276 EP |
645 | { |
646 | struct fsnotify_mark *fsn_mark; | |
912ee394 | 647 | __u32 added; |
88826276 EP |
648 | |
649 | pr_debug("%s: group=%p inode=%p\n", __func__, group, inode); | |
2a3edf86 | 650 | |
5322a59f EP |
651 | /* |
652 | * If some other task has this inode open for write we should not add | |
653 | * an ignored mark, unless that ignored mark is supposed to survive | |
654 | * modification changes anyway. | |
655 | */ | |
656 | if ((flags & FAN_MARK_IGNORED_MASK) && | |
657 | !(flags & FAN_MARK_IGNORED_SURV_MODIFY) && | |
658 | (atomic_read(&inode->i_writecount) > 0)) | |
659 | return 0; | |
660 | ||
7b18527c | 661 | mutex_lock(&group->mark_mutex); |
5444e298 | 662 | fsn_mark = fsnotify_find_inode_mark(group, inode); |
2a3edf86 | 663 | if (!fsn_mark) { |
5e9c070c LS |
664 | fsn_mark = fanotify_add_new_mark(group, inode, NULL); |
665 | if (IS_ERR(fsn_mark)) { | |
7b18527c | 666 | mutex_unlock(&group->mark_mutex); |
5e9c070c | 667 | return PTR_ERR(fsn_mark); |
7b18527c | 668 | } |
2a3edf86 | 669 | } |
b9e4e3bd | 670 | added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); |
7b18527c | 671 | mutex_unlock(&group->mark_mutex); |
fa218ab9 | 672 | |
43709a28 EP |
673 | if (added & ~inode->i_fsnotify_mask) |
674 | fsnotify_recalc_inode_mask(inode); | |
5e9c070c | 675 | |
fa218ab9 | 676 | fsnotify_put_mark(fsn_mark); |
5e9c070c | 677 | return 0; |
88826276 | 678 | } |
2a3edf86 | 679 | |
52c923dd | 680 | /* fanotify syscalls */ |
08ae8938 | 681 | SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) |
11637e4b | 682 | { |
52c923dd EP |
683 | struct fsnotify_group *group; |
684 | int f_flags, fd; | |
4afeff85 | 685 | struct user_struct *user; |
ff57cd58 | 686 | struct fanotify_event_info *oevent; |
52c923dd | 687 | |
08ae8938 EP |
688 | pr_debug("%s: flags=%d event_f_flags=%d\n", |
689 | __func__, flags, event_f_flags); | |
52c923dd | 690 | |
52c923dd | 691 | if (!capable(CAP_SYS_ADMIN)) |
a2f13ad0 | 692 | return -EPERM; |
52c923dd EP |
693 | |
694 | if (flags & ~FAN_ALL_INIT_FLAGS) | |
695 | return -EINVAL; | |
696 | ||
48149e9d HS |
697 | if (event_f_flags & ~FANOTIFY_INIT_ALL_EVENT_F_BITS) |
698 | return -EINVAL; | |
699 | ||
700 | switch (event_f_flags & O_ACCMODE) { | |
701 | case O_RDONLY: | |
702 | case O_RDWR: | |
703 | case O_WRONLY: | |
704 | break; | |
705 | default: | |
706 | return -EINVAL; | |
707 | } | |
708 | ||
4afeff85 EP |
709 | user = get_current_user(); |
710 | if (atomic_read(&user->fanotify_listeners) > FANOTIFY_DEFAULT_MAX_LISTENERS) { | |
711 | free_uid(user); | |
712 | return -EMFILE; | |
713 | } | |
714 | ||
b2d87909 | 715 | f_flags = O_RDWR | FMODE_NONOTIFY; |
52c923dd EP |
716 | if (flags & FAN_CLOEXEC) |
717 | f_flags |= O_CLOEXEC; | |
718 | if (flags & FAN_NONBLOCK) | |
719 | f_flags |= O_NONBLOCK; | |
720 | ||
721 | /* fsnotify_alloc_group takes a ref. Dropped in fanotify_release */ | |
722 | group = fsnotify_alloc_group(&fanotify_fsnotify_ops); | |
26379198 EP |
723 | if (IS_ERR(group)) { |
724 | free_uid(user); | |
52c923dd | 725 | return PTR_ERR(group); |
26379198 | 726 | } |
52c923dd | 727 | |
4afeff85 EP |
728 | group->fanotify_data.user = user; |
729 | atomic_inc(&user->fanotify_listeners); | |
730 | ||
f083441b | 731 | oevent = fanotify_alloc_event(NULL, FS_Q_OVERFLOW, NULL); |
ff57cd58 JK |
732 | if (unlikely(!oevent)) { |
733 | fd = -ENOMEM; | |
734 | goto out_destroy_group; | |
735 | } | |
736 | group->overflow_event = &oevent->fse; | |
ff57cd58 | 737 | |
1e2ee49f WW |
738 | if (force_o_largefile()) |
739 | event_f_flags |= O_LARGEFILE; | |
80af2588 | 740 | group->fanotify_data.f_flags = event_f_flags; |
9e66e423 | 741 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
9573f793 | 742 | spin_lock_init(&group->fanotify_data.access_lock); |
9e66e423 EP |
743 | init_waitqueue_head(&group->fanotify_data.access_waitq); |
744 | INIT_LIST_HEAD(&group->fanotify_data.access_list); | |
09e5f14e | 745 | atomic_set(&group->fanotify_data.bypass_perm, 0); |
9e66e423 | 746 | #endif |
4231a235 EP |
747 | switch (flags & FAN_ALL_CLASS_BITS) { |
748 | case FAN_CLASS_NOTIF: | |
749 | group->priority = FS_PRIO_0; | |
750 | break; | |
751 | case FAN_CLASS_CONTENT: | |
752 | group->priority = FS_PRIO_1; | |
753 | break; | |
754 | case FAN_CLASS_PRE_CONTENT: | |
755 | group->priority = FS_PRIO_2; | |
756 | break; | |
757 | default: | |
758 | fd = -EINVAL; | |
d8153d4d | 759 | goto out_destroy_group; |
4231a235 | 760 | } |
cb2d429f | 761 | |
5dd03f55 EP |
762 | if (flags & FAN_UNLIMITED_QUEUE) { |
763 | fd = -EPERM; | |
764 | if (!capable(CAP_SYS_ADMIN)) | |
d8153d4d | 765 | goto out_destroy_group; |
5dd03f55 EP |
766 | group->max_events = UINT_MAX; |
767 | } else { | |
768 | group->max_events = FANOTIFY_DEFAULT_MAX_EVENTS; | |
769 | } | |
2529a0df | 770 | |
ac7e22dc EP |
771 | if (flags & FAN_UNLIMITED_MARKS) { |
772 | fd = -EPERM; | |
773 | if (!capable(CAP_SYS_ADMIN)) | |
d8153d4d | 774 | goto out_destroy_group; |
ac7e22dc EP |
775 | group->fanotify_data.max_marks = UINT_MAX; |
776 | } else { | |
777 | group->fanotify_data.max_marks = FANOTIFY_DEFAULT_MAX_MARKS; | |
778 | } | |
e7099d8a | 779 | |
52c923dd EP |
780 | fd = anon_inode_getfd("[fanotify]", &fanotify_fops, group, f_flags); |
781 | if (fd < 0) | |
d8153d4d | 782 | goto out_destroy_group; |
52c923dd EP |
783 | |
784 | return fd; | |
785 | ||
d8153d4d LS |
786 | out_destroy_group: |
787 | fsnotify_destroy_group(group); | |
52c923dd | 788 | return fd; |
11637e4b | 789 | } |
bbaa4168 | 790 | |
4a0fd5bf AV |
791 | SYSCALL_DEFINE5(fanotify_mark, int, fanotify_fd, unsigned int, flags, |
792 | __u64, mask, int, dfd, | |
793 | const char __user *, pathname) | |
bbaa4168 | 794 | { |
0ff21db9 EP |
795 | struct inode *inode = NULL; |
796 | struct vfsmount *mnt = NULL; | |
2a3edf86 | 797 | struct fsnotify_group *group; |
2903ff01 | 798 | struct fd f; |
2a3edf86 | 799 | struct path path; |
2903ff01 | 800 | int ret; |
2a3edf86 EP |
801 | |
802 | pr_debug("%s: fanotify_fd=%d flags=%x dfd=%d pathname=%p mask=%llx\n", | |
803 | __func__, fanotify_fd, flags, dfd, pathname, mask); | |
804 | ||
805 | /* we only use the lower 32 bits as of right now. */ | |
806 | if (mask & ((__u64)0xffffffff << 32)) | |
807 | return -EINVAL; | |
808 | ||
88380fe6 AG |
809 | if (flags & ~FAN_ALL_MARK_FLAGS) |
810 | return -EINVAL; | |
4d92604c | 811 | switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) { |
1734dee4 | 812 | case FAN_MARK_ADD: /* fallthrough */ |
88380fe6 | 813 | case FAN_MARK_REMOVE: |
1734dee4 LS |
814 | if (!mask) |
815 | return -EINVAL; | |
cc299a98 | 816 | break; |
4d92604c | 817 | case FAN_MARK_FLUSH: |
cc299a98 HS |
818 | if (flags & ~(FAN_MARK_MOUNT | FAN_MARK_FLUSH)) |
819 | return -EINVAL; | |
88380fe6 AG |
820 | break; |
821 | default: | |
822 | return -EINVAL; | |
823 | } | |
8fcd6528 EP |
824 | |
825 | if (mask & FAN_ONDIR) { | |
826 | flags |= FAN_MARK_ONDIR; | |
827 | mask &= ~FAN_ONDIR; | |
828 | } | |
829 | ||
b2d87909 EP |
830 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
831 | if (mask & ~(FAN_ALL_EVENTS | FAN_ALL_PERM_EVENTS | FAN_EVENT_ON_CHILD)) | |
832 | #else | |
88380fe6 | 833 | if (mask & ~(FAN_ALL_EVENTS | FAN_EVENT_ON_CHILD)) |
b2d87909 | 834 | #endif |
2a3edf86 EP |
835 | return -EINVAL; |
836 | ||
2903ff01 AV |
837 | f = fdget(fanotify_fd); |
838 | if (unlikely(!f.file)) | |
2a3edf86 EP |
839 | return -EBADF; |
840 | ||
841 | /* verify that this is indeed an fanotify instance */ | |
842 | ret = -EINVAL; | |
2903ff01 | 843 | if (unlikely(f.file->f_op != &fanotify_fops)) |
2a3edf86 | 844 | goto fput_and_out; |
2903ff01 | 845 | group = f.file->private_data; |
4231a235 EP |
846 | |
847 | /* | |
848 | * group->priority == FS_PRIO_0 == FAN_CLASS_NOTIF. These are not | |
849 | * allowed to set permissions events. | |
850 | */ | |
851 | ret = -EINVAL; | |
852 | if (mask & FAN_ALL_PERM_EVENTS && | |
853 | group->priority == FS_PRIO_0) | |
854 | goto fput_and_out; | |
2a3edf86 | 855 | |
0a8dd2db HS |
856 | if (flags & FAN_MARK_FLUSH) { |
857 | ret = 0; | |
858 | if (flags & FAN_MARK_MOUNT) | |
859 | fsnotify_clear_vfsmount_marks_by_group(group); | |
860 | else | |
861 | fsnotify_clear_inode_marks_by_group(group); | |
862 | goto fput_and_out; | |
863 | } | |
864 | ||
2a3edf86 EP |
865 | ret = fanotify_find_path(dfd, pathname, &path, flags); |
866 | if (ret) | |
867 | goto fput_and_out; | |
868 | ||
869 | /* inode held in place by reference to path; group by fget on fd */ | |
eac8e9e8 | 870 | if (!(flags & FAN_MARK_MOUNT)) |
0ff21db9 EP |
871 | inode = path.dentry->d_inode; |
872 | else | |
873 | mnt = path.mnt; | |
2a3edf86 EP |
874 | |
875 | /* create/update an inode mark */ | |
0a8dd2db | 876 | switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE)) { |
c6223f46 | 877 | case FAN_MARK_ADD: |
eac8e9e8 | 878 | if (flags & FAN_MARK_MOUNT) |
b9e4e3bd | 879 | ret = fanotify_add_vfsmount_mark(group, mnt, mask, flags); |
0ff21db9 | 880 | else |
b9e4e3bd | 881 | ret = fanotify_add_inode_mark(group, inode, mask, flags); |
c6223f46 AG |
882 | break; |
883 | case FAN_MARK_REMOVE: | |
f3640192 | 884 | if (flags & FAN_MARK_MOUNT) |
b9e4e3bd | 885 | ret = fanotify_remove_vfsmount_mark(group, mnt, mask, flags); |
f3640192 | 886 | else |
b9e4e3bd | 887 | ret = fanotify_remove_inode_mark(group, inode, mask, flags); |
c6223f46 AG |
888 | break; |
889 | default: | |
890 | ret = -EINVAL; | |
891 | } | |
2a3edf86 EP |
892 | |
893 | path_put(&path); | |
894 | fput_and_out: | |
2903ff01 | 895 | fdput(f); |
2a3edf86 EP |
896 | return ret; |
897 | } | |
898 | ||
91c2e0bc AV |
899 | #ifdef CONFIG_COMPAT |
900 | COMPAT_SYSCALL_DEFINE6(fanotify_mark, | |
901 | int, fanotify_fd, unsigned int, flags, | |
902 | __u32, mask0, __u32, mask1, int, dfd, | |
903 | const char __user *, pathname) | |
904 | { | |
905 | return sys_fanotify_mark(fanotify_fd, flags, | |
906 | #ifdef __BIG_ENDIAN | |
91c2e0bc | 907 | ((__u64)mask0 << 32) | mask1, |
592f6b84 HC |
908 | #else |
909 | ((__u64)mask1 << 32) | mask0, | |
91c2e0bc AV |
910 | #endif |
911 | dfd, pathname); | |
912 | } | |
913 | #endif | |
914 | ||
2a3edf86 | 915 | /* |
ae0e47f0 | 916 | * fanotify_user_setup - Our initialization function. Note that we cannot return |
2a3edf86 EP |
917 | * error because we have compiled-in VFS hooks. So an (unlikely) failure here |
918 | * must result in panic(). | |
919 | */ | |
920 | static int __init fanotify_user_setup(void) | |
921 | { | |
922 | fanotify_mark_cache = KMEM_CACHE(fsnotify_mark, SLAB_PANIC); | |
7053aee2 | 923 | fanotify_event_cachep = KMEM_CACHE(fanotify_event_info, SLAB_PANIC); |
f083441b JK |
924 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
925 | fanotify_perm_event_cachep = KMEM_CACHE(fanotify_perm_event_info, | |
926 | SLAB_PANIC); | |
927 | #endif | |
2a3edf86 EP |
928 | |
929 | return 0; | |
bbaa4168 | 930 | } |
2a3edf86 | 931 | device_initcall(fanotify_user_setup); |