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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 | 15 | #include <linux/uaccess.h> |
91c2e0bc | 16 | #include <linux/compat.h> |
174cd4b1 | 17 | #include <linux/sched/signal.h> |
a1014f10 EP |
18 | |
19 | #include <asm/ioctls.h> | |
11637e4b | 20 | |
c63181e6 | 21 | #include "../../mount.h" |
be77196b | 22 | #include "../fdinfo.h" |
7053aee2 | 23 | #include "fanotify.h" |
c63181e6 | 24 | |
2529a0df | 25 | #define FANOTIFY_DEFAULT_MAX_EVENTS 16384 |
e7099d8a | 26 | #define FANOTIFY_DEFAULT_MAX_MARKS 8192 |
4afeff85 | 27 | #define FANOTIFY_DEFAULT_MAX_LISTENERS 128 |
2529a0df | 28 | |
48149e9d HS |
29 | /* |
30 | * All flags that may be specified in parameter event_f_flags of fanotify_init. | |
31 | * | |
32 | * Internal and external open flags are stored together in field f_flags of | |
33 | * struct file. Only external open flags shall be allowed in event_f_flags. | |
34 | * Internal flags like FMODE_NONOTIFY, FMODE_EXEC, FMODE_NOCMTIME shall be | |
35 | * excluded. | |
36 | */ | |
37 | #define FANOTIFY_INIT_ALL_EVENT_F_BITS ( \ | |
38 | O_ACCMODE | O_APPEND | O_NONBLOCK | \ | |
39 | __O_SYNC | O_DSYNC | O_CLOEXEC | \ | |
40 | O_LARGEFILE | O_NOATIME ) | |
41 | ||
33d3dfff | 42 | extern const struct fsnotify_ops fanotify_fsnotify_ops; |
11637e4b | 43 | |
2a3edf86 | 44 | static struct kmem_cache *fanotify_mark_cache __read_mostly; |
7053aee2 | 45 | struct kmem_cache *fanotify_event_cachep __read_mostly; |
f083441b | 46 | struct kmem_cache *fanotify_perm_event_cachep __read_mostly; |
2a3edf86 | 47 | |
a1014f10 EP |
48 | /* |
49 | * Get an fsnotify notification event if one exists and is small | |
50 | * enough to fit in "count". Return an error pointer if the count | |
51 | * is not large enough. | |
52 | * | |
c21dbe20 | 53 | * Called with the group->notification_lock held. |
a1014f10 EP |
54 | */ |
55 | static struct fsnotify_event *get_one_event(struct fsnotify_group *group, | |
56 | size_t count) | |
57 | { | |
ed272640 | 58 | assert_spin_locked(&group->notification_lock); |
a1014f10 EP |
59 | |
60 | pr_debug("%s: group=%p count=%zd\n", __func__, group, count); | |
61 | ||
62 | if (fsnotify_notify_queue_is_empty(group)) | |
63 | return NULL; | |
64 | ||
65 | if (FAN_EVENT_METADATA_LEN > count) | |
66 | return ERR_PTR(-EINVAL); | |
67 | ||
c21dbe20 | 68 | /* held the notification_lock the whole time, so this is the |
a1014f10 | 69 | * same event we peeked above */ |
8ba8fa91 | 70 | return fsnotify_remove_first_event(group); |
a1014f10 EP |
71 | } |
72 | ||
352e3b24 | 73 | static int create_fd(struct fsnotify_group *group, |
7053aee2 JK |
74 | struct fanotify_event_info *event, |
75 | struct file **file) | |
a1014f10 EP |
76 | { |
77 | int client_fd; | |
a1014f10 EP |
78 | struct file *new_file; |
79 | ||
22aa425d | 80 | pr_debug("%s: group=%p event=%p\n", __func__, group, event); |
a1014f10 | 81 | |
0b37e097 | 82 | client_fd = get_unused_fd_flags(group->fanotify_data.f_flags); |
a1014f10 EP |
83 | if (client_fd < 0) |
84 | return client_fd; | |
85 | ||
a1014f10 EP |
86 | /* |
87 | * we need a new file handle for the userspace program so it can read even if it was | |
88 | * originally opened O_WRONLY. | |
89 | */ | |
a1014f10 EP |
90 | /* it's possible this event was an overflow event. in that case dentry and mnt |
91 | * are NULL; That's fine, just don't call dentry open */ | |
765927b2 AV |
92 | if (event->path.dentry && event->path.mnt) |
93 | new_file = dentry_open(&event->path, | |
80af2588 | 94 | group->fanotify_data.f_flags | FMODE_NONOTIFY, |
a1014f10 EP |
95 | current_cred()); |
96 | else | |
97 | new_file = ERR_PTR(-EOVERFLOW); | |
98 | if (IS_ERR(new_file)) { | |
99 | /* | |
100 | * we still send an event even if we can't open the file. this | |
101 | * can happen when say tasks are gone and we try to open their | |
102 | * /proc files or we try to open a WRONLY file like in sysfs | |
103 | * we just send the errno to userspace since there isn't much | |
104 | * else we can do. | |
105 | */ | |
106 | put_unused_fd(client_fd); | |
107 | client_fd = PTR_ERR(new_file); | |
108 | } else { | |
352e3b24 | 109 | *file = new_file; |
a1014f10 EP |
110 | } |
111 | ||
22aa425d | 112 | return client_fd; |
a1014f10 EP |
113 | } |
114 | ||
ecf6f5e7 | 115 | static int fill_event_metadata(struct fsnotify_group *group, |
7053aee2 JK |
116 | struct fanotify_event_metadata *metadata, |
117 | struct fsnotify_event *fsn_event, | |
118 | struct file **file) | |
a1014f10 | 119 | { |
fdbf3cee | 120 | int ret = 0; |
7053aee2 | 121 | struct fanotify_event_info *event; |
fdbf3cee | 122 | |
a1014f10 | 123 | pr_debug("%s: group=%p metadata=%p event=%p\n", __func__, |
7053aee2 | 124 | group, metadata, fsn_event); |
a1014f10 | 125 | |
352e3b24 | 126 | *file = NULL; |
7053aee2 | 127 | event = container_of(fsn_event, struct fanotify_event_info, fse); |
a1014f10 | 128 | metadata->event_len = FAN_EVENT_METADATA_LEN; |
7d131623 | 129 | metadata->metadata_len = FAN_EVENT_METADATA_LEN; |
a1014f10 | 130 | metadata->vers = FANOTIFY_METADATA_VERSION; |
de1e0c40 | 131 | metadata->reserved = 0; |
7053aee2 | 132 | metadata->mask = fsn_event->mask & FAN_ALL_OUTGOING_EVENTS; |
32c32632 | 133 | metadata->pid = pid_vnr(event->tgid); |
7053aee2 | 134 | if (unlikely(fsn_event->mask & FAN_Q_OVERFLOW)) |
fdbf3cee LS |
135 | metadata->fd = FAN_NOFD; |
136 | else { | |
352e3b24 | 137 | metadata->fd = create_fd(group, event, file); |
fdbf3cee LS |
138 | if (metadata->fd < 0) |
139 | ret = metadata->fd; | |
140 | } | |
a1014f10 | 141 | |
fdbf3cee | 142 | return ret; |
a1014f10 EP |
143 | } |
144 | ||
b2d87909 | 145 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
f083441b JK |
146 | static struct fanotify_perm_event_info *dequeue_event( |
147 | struct fsnotify_group *group, int fd) | |
b2d87909 | 148 | { |
f083441b | 149 | struct fanotify_perm_event_info *event, *return_e = NULL; |
b2d87909 | 150 | |
073f6552 | 151 | spin_lock(&group->notification_lock); |
f083441b JK |
152 | list_for_each_entry(event, &group->fanotify_data.access_list, |
153 | fae.fse.list) { | |
154 | if (event->fd != fd) | |
b2d87909 EP |
155 | continue; |
156 | ||
f083441b JK |
157 | list_del_init(&event->fae.fse.list); |
158 | return_e = event; | |
b2d87909 EP |
159 | break; |
160 | } | |
073f6552 | 161 | spin_unlock(&group->notification_lock); |
b2d87909 | 162 | |
f083441b | 163 | pr_debug("%s: found return_re=%p\n", __func__, return_e); |
b2d87909 | 164 | |
f083441b | 165 | return return_e; |
b2d87909 EP |
166 | } |
167 | ||
168 | static int process_access_response(struct fsnotify_group *group, | |
169 | struct fanotify_response *response_struct) | |
170 | { | |
f083441b JK |
171 | struct fanotify_perm_event_info *event; |
172 | int fd = response_struct->fd; | |
173 | int response = response_struct->response; | |
b2d87909 EP |
174 | |
175 | pr_debug("%s: group=%p fd=%d response=%d\n", __func__, group, | |
176 | fd, response); | |
177 | /* | |
178 | * make sure the response is valid, if invalid we do nothing and either | |
25985edc | 179 | * userspace can send a valid response or we will clean it up after the |
b2d87909 EP |
180 | * timeout |
181 | */ | |
182 | switch (response) { | |
183 | case FAN_ALLOW: | |
184 | case FAN_DENY: | |
185 | break; | |
186 | default: | |
187 | return -EINVAL; | |
188 | } | |
189 | ||
190 | if (fd < 0) | |
191 | return -EINVAL; | |
192 | ||
f083441b JK |
193 | event = dequeue_event(group, fd); |
194 | if (!event) | |
b2d87909 EP |
195 | return -ENOENT; |
196 | ||
f083441b | 197 | event->response = response; |
b2d87909 EP |
198 | wake_up(&group->fanotify_data.access_waitq); |
199 | ||
b2d87909 EP |
200 | return 0; |
201 | } | |
b2d87909 EP |
202 | #endif |
203 | ||
a1014f10 EP |
204 | static ssize_t copy_event_to_user(struct fsnotify_group *group, |
205 | struct fsnotify_event *event, | |
206 | char __user *buf) | |
207 | { | |
208 | struct fanotify_event_metadata fanotify_event_metadata; | |
352e3b24 | 209 | struct file *f; |
b2d87909 | 210 | int fd, ret; |
a1014f10 EP |
211 | |
212 | pr_debug("%s: group=%p event=%p\n", __func__, group, event); | |
213 | ||
352e3b24 | 214 | ret = fill_event_metadata(group, &fanotify_event_metadata, event, &f); |
ecf6f5e7 | 215 | if (ret < 0) |
d507816b | 216 | return ret; |
b2d87909 | 217 | |
fdbf3cee | 218 | fd = fanotify_event_metadata.fd; |
b2d87909 | 219 | ret = -EFAULT; |
7d131623 EP |
220 | if (copy_to_user(buf, &fanotify_event_metadata, |
221 | fanotify_event_metadata.event_len)) | |
352e3b24 AV |
222 | goto out_close_fd; |
223 | ||
f083441b | 224 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
d507816b JK |
225 | if (event->mask & FAN_ALL_PERM_EVENTS) |
226 | FANOTIFY_PE(event)->fd = fd; | |
f083441b | 227 | #endif |
a1014f10 | 228 | |
3587b1b0 AV |
229 | if (fd != FAN_NOFD) |
230 | fd_install(fd, f); | |
7d131623 | 231 | return fanotify_event_metadata.event_len; |
b2d87909 | 232 | |
b2d87909 | 233 | out_close_fd: |
352e3b24 AV |
234 | if (fd != FAN_NOFD) { |
235 | put_unused_fd(fd); | |
236 | fput(f); | |
237 | } | |
b2d87909 | 238 | return ret; |
a1014f10 EP |
239 | } |
240 | ||
241 | /* intofiy userspace file descriptor functions */ | |
242 | static unsigned int fanotify_poll(struct file *file, poll_table *wait) | |
243 | { | |
244 | struct fsnotify_group *group = file->private_data; | |
245 | int ret = 0; | |
246 | ||
247 | poll_wait(file, &group->notification_waitq, wait); | |
c21dbe20 | 248 | spin_lock(&group->notification_lock); |
a1014f10 EP |
249 | if (!fsnotify_notify_queue_is_empty(group)) |
250 | ret = POLLIN | POLLRDNORM; | |
c21dbe20 | 251 | spin_unlock(&group->notification_lock); |
a1014f10 EP |
252 | |
253 | return ret; | |
254 | } | |
255 | ||
256 | static ssize_t fanotify_read(struct file *file, char __user *buf, | |
257 | size_t count, loff_t *pos) | |
258 | { | |
259 | struct fsnotify_group *group; | |
260 | struct fsnotify_event *kevent; | |
261 | char __user *start; | |
262 | int ret; | |
536ebe9c | 263 | DEFINE_WAIT_FUNC(wait, woken_wake_function); |
a1014f10 EP |
264 | |
265 | start = buf; | |
266 | group = file->private_data; | |
267 | ||
268 | pr_debug("%s: group=%p\n", __func__, group); | |
269 | ||
536ebe9c | 270 | add_wait_queue(&group->notification_waitq, &wait); |
a1014f10 | 271 | while (1) { |
c21dbe20 | 272 | spin_lock(&group->notification_lock); |
a1014f10 | 273 | kevent = get_one_event(group, count); |
c21dbe20 | 274 | spin_unlock(&group->notification_lock); |
a1014f10 | 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; |
536ebe9c PZ |
292 | |
293 | wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); | |
a1014f10 EP |
294 | continue; |
295 | } | |
296 | ||
d8aaab4f JK |
297 | ret = copy_event_to_user(group, kevent, buf); |
298 | /* | |
299 | * Permission events get queued to wait for response. Other | |
300 | * events can be destroyed now. | |
301 | */ | |
d507816b | 302 | if (!(kevent->mask & FAN_ALL_PERM_EVENTS)) { |
d8aaab4f | 303 | fsnotify_destroy_event(group, kevent); |
d507816b JK |
304 | if (ret < 0) |
305 | break; | |
306 | } else { | |
307 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS | |
308 | if (ret < 0) { | |
309 | FANOTIFY_PE(kevent)->response = FAN_DENY; | |
310 | wake_up(&group->fanotify_data.access_waitq); | |
311 | break; | |
312 | } | |
073f6552 | 313 | spin_lock(&group->notification_lock); |
d507816b JK |
314 | list_add_tail(&kevent->list, |
315 | &group->fanotify_data.access_list); | |
073f6552 | 316 | spin_unlock(&group->notification_lock); |
d507816b JK |
317 | #endif |
318 | } | |
d8aaab4f JK |
319 | buf += ret; |
320 | count -= ret; | |
a1014f10 | 321 | } |
536ebe9c | 322 | remove_wait_queue(&group->notification_waitq, &wait); |
a1014f10 | 323 | |
a1014f10 EP |
324 | if (start != buf && ret != -EFAULT) |
325 | ret = buf - start; | |
326 | return ret; | |
327 | } | |
328 | ||
b2d87909 EP |
329 | static ssize_t fanotify_write(struct file *file, const char __user *buf, size_t count, loff_t *pos) |
330 | { | |
331 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS | |
332 | struct fanotify_response response = { .fd = -1, .response = -1 }; | |
333 | struct fsnotify_group *group; | |
334 | int ret; | |
335 | ||
336 | group = file->private_data; | |
337 | ||
338 | if (count > sizeof(response)) | |
339 | count = sizeof(response); | |
340 | ||
341 | pr_debug("%s: group=%p count=%zu\n", __func__, group, count); | |
342 | ||
343 | if (copy_from_user(&response, buf, count)) | |
344 | return -EFAULT; | |
345 | ||
346 | ret = process_access_response(group, &response); | |
347 | if (ret < 0) | |
348 | count = ret; | |
349 | ||
350 | return count; | |
351 | #else | |
352 | return -EINVAL; | |
353 | #endif | |
354 | } | |
355 | ||
52c923dd EP |
356 | static int fanotify_release(struct inode *ignored, struct file *file) |
357 | { | |
358 | struct fsnotify_group *group = file->private_data; | |
52c923dd | 359 | |
2eebf582 | 360 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
f083441b | 361 | struct fanotify_perm_event_info *event, *next; |
96d41019 | 362 | struct fsnotify_event *fsn_event; |
19ba54f4 | 363 | |
5838d444 | 364 | /* |
96d41019 JK |
365 | * Stop new events from arriving in the notification queue. since |
366 | * userspace cannot use fanotify fd anymore, no event can enter or | |
367 | * leave access_list by now either. | |
5838d444 | 368 | */ |
96d41019 | 369 | fsnotify_group_stop_queueing(group); |
2eebf582 | 370 | |
96d41019 JK |
371 | /* |
372 | * Process all permission events on access_list and notification queue | |
373 | * and simulate reply from userspace. | |
374 | */ | |
073f6552 | 375 | spin_lock(&group->notification_lock); |
f083441b JK |
376 | list_for_each_entry_safe(event, next, &group->fanotify_data.access_list, |
377 | fae.fse.list) { | |
378 | pr_debug("%s: found group=%p event=%p\n", __func__, group, | |
379 | event); | |
2eebf582 | 380 | |
f083441b JK |
381 | list_del_init(&event->fae.fse.list); |
382 | event->response = FAN_ALLOW; | |
2eebf582 | 383 | } |
2eebf582 | 384 | |
5838d444 | 385 | /* |
96d41019 JK |
386 | * Destroy all non-permission events. For permission events just |
387 | * dequeue them and set the response. They will be freed once the | |
388 | * response is consumed and fanotify_get_response() returns. | |
5838d444 | 389 | */ |
96d41019 JK |
390 | while (!fsnotify_notify_queue_is_empty(group)) { |
391 | fsn_event = fsnotify_remove_first_event(group); | |
1404ff3c | 392 | if (!(fsn_event->mask & FAN_ALL_PERM_EVENTS)) { |
c21dbe20 | 393 | spin_unlock(&group->notification_lock); |
96d41019 | 394 | fsnotify_destroy_event(group, fsn_event); |
c21dbe20 | 395 | spin_lock(&group->notification_lock); |
1404ff3c | 396 | } else |
96d41019 JK |
397 | FANOTIFY_PE(fsn_event)->response = FAN_ALLOW; |
398 | } | |
c21dbe20 | 399 | spin_unlock(&group->notification_lock); |
96d41019 JK |
400 | |
401 | /* Response for all permission events it set, wakeup waiters */ | |
2eebf582 EP |
402 | wake_up(&group->fanotify_data.access_waitq); |
403 | #endif | |
0a6b6bd5 | 404 | |
52c923dd | 405 | /* matches the fanotify_init->fsnotify_alloc_group */ |
d8153d4d | 406 | fsnotify_destroy_group(group); |
52c923dd EP |
407 | |
408 | return 0; | |
409 | } | |
410 | ||
a1014f10 EP |
411 | static long fanotify_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
412 | { | |
413 | struct fsnotify_group *group; | |
7053aee2 | 414 | struct fsnotify_event *fsn_event; |
a1014f10 EP |
415 | void __user *p; |
416 | int ret = -ENOTTY; | |
417 | size_t send_len = 0; | |
418 | ||
419 | group = file->private_data; | |
420 | ||
421 | p = (void __user *) arg; | |
422 | ||
423 | switch (cmd) { | |
424 | case FIONREAD: | |
c21dbe20 | 425 | spin_lock(&group->notification_lock); |
7053aee2 | 426 | list_for_each_entry(fsn_event, &group->notification_list, list) |
a1014f10 | 427 | send_len += FAN_EVENT_METADATA_LEN; |
c21dbe20 | 428 | spin_unlock(&group->notification_lock); |
a1014f10 EP |
429 | ret = put_user(send_len, (int __user *) p); |
430 | break; | |
431 | } | |
432 | ||
433 | return ret; | |
434 | } | |
435 | ||
52c923dd | 436 | static const struct file_operations fanotify_fops = { |
be77196b | 437 | .show_fdinfo = fanotify_show_fdinfo, |
a1014f10 EP |
438 | .poll = fanotify_poll, |
439 | .read = fanotify_read, | |
b2d87909 | 440 | .write = fanotify_write, |
52c923dd EP |
441 | .fasync = NULL, |
442 | .release = fanotify_release, | |
a1014f10 EP |
443 | .unlocked_ioctl = fanotify_ioctl, |
444 | .compat_ioctl = fanotify_ioctl, | |
6038f373 | 445 | .llseek = noop_llseek, |
52c923dd EP |
446 | }; |
447 | ||
2a3edf86 EP |
448 | static void fanotify_free_mark(struct fsnotify_mark *fsn_mark) |
449 | { | |
450 | kmem_cache_free(fanotify_mark_cache, fsn_mark); | |
451 | } | |
452 | ||
453 | static int fanotify_find_path(int dfd, const char __user *filename, | |
454 | struct path *path, unsigned int flags) | |
455 | { | |
456 | int ret; | |
457 | ||
458 | pr_debug("%s: dfd=%d filename=%p flags=%x\n", __func__, | |
459 | dfd, filename, flags); | |
460 | ||
461 | if (filename == NULL) { | |
2903ff01 | 462 | struct fd f = fdget(dfd); |
2a3edf86 EP |
463 | |
464 | ret = -EBADF; | |
2903ff01 | 465 | if (!f.file) |
2a3edf86 EP |
466 | goto out; |
467 | ||
468 | ret = -ENOTDIR; | |
469 | if ((flags & FAN_MARK_ONLYDIR) && | |
496ad9aa | 470 | !(S_ISDIR(file_inode(f.file)->i_mode))) { |
2903ff01 | 471 | fdput(f); |
2a3edf86 EP |
472 | goto out; |
473 | } | |
474 | ||
2903ff01 | 475 | *path = f.file->f_path; |
2a3edf86 | 476 | path_get(path); |
2903ff01 | 477 | fdput(f); |
2a3edf86 EP |
478 | } else { |
479 | unsigned int lookup_flags = 0; | |
480 | ||
481 | if (!(flags & FAN_MARK_DONT_FOLLOW)) | |
482 | lookup_flags |= LOOKUP_FOLLOW; | |
483 | if (flags & FAN_MARK_ONLYDIR) | |
484 | lookup_flags |= LOOKUP_DIRECTORY; | |
485 | ||
486 | ret = user_path_at(dfd, filename, lookup_flags, path); | |
487 | if (ret) | |
488 | goto out; | |
489 | } | |
490 | ||
491 | /* you can only watch an inode if you have read permissions on it */ | |
492 | ret = inode_permission(path->dentry->d_inode, MAY_READ); | |
493 | if (ret) | |
494 | path_put(path); | |
495 | out: | |
496 | return ret; | |
497 | } | |
498 | ||
b9e4e3bd EP |
499 | static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark, |
500 | __u32 mask, | |
6dfbd149 LS |
501 | unsigned int flags, |
502 | int *destroy) | |
088b09b0 | 503 | { |
d2c1874c | 504 | __u32 oldmask = 0; |
088b09b0 AG |
505 | |
506 | spin_lock(&fsn_mark->lock); | |
b9e4e3bd | 507 | if (!(flags & FAN_MARK_IGNORED_MASK)) { |
66ba93c0 LS |
508 | __u32 tmask = fsn_mark->mask & ~mask; |
509 | ||
510 | if (flags & FAN_MARK_ONDIR) | |
511 | tmask &= ~FAN_ONDIR; | |
512 | ||
b9e4e3bd | 513 | oldmask = fsn_mark->mask; |
66d2b81b | 514 | fsn_mark->mask = tmask; |
b9e4e3bd | 515 | } else { |
d2c1874c | 516 | __u32 tmask = fsn_mark->ignored_mask & ~mask; |
66ba93c0 LS |
517 | if (flags & FAN_MARK_ONDIR) |
518 | tmask &= ~FAN_ONDIR; | |
66d2b81b | 519 | fsn_mark->ignored_mask = tmask; |
b9e4e3bd | 520 | } |
a118449a | 521 | *destroy = !(fsn_mark->mask | fsn_mark->ignored_mask); |
088b09b0 AG |
522 | spin_unlock(&fsn_mark->lock); |
523 | ||
088b09b0 AG |
524 | return mask & oldmask; |
525 | } | |
526 | ||
f3640192 | 527 | static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group, |
b9e4e3bd EP |
528 | struct vfsmount *mnt, __u32 mask, |
529 | unsigned int flags) | |
88826276 EP |
530 | { |
531 | struct fsnotify_mark *fsn_mark = NULL; | |
088b09b0 | 532 | __u32 removed; |
6dfbd149 | 533 | int destroy_mark; |
88826276 | 534 | |
7b18527c | 535 | mutex_lock(&group->mark_mutex); |
f3640192 | 536 | fsn_mark = fsnotify_find_vfsmount_mark(group, mnt); |
7b18527c LS |
537 | if (!fsn_mark) { |
538 | mutex_unlock(&group->mark_mutex); | |
f3640192 | 539 | return -ENOENT; |
7b18527c | 540 | } |
88826276 | 541 | |
6dfbd149 LS |
542 | removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags, |
543 | &destroy_mark); | |
c9747640 | 544 | if (removed & real_mount(mnt)->mnt_fsnotify_mask) |
8920d273 | 545 | fsnotify_recalc_mask(real_mount(mnt)->mnt_fsnotify_marks); |
6dfbd149 | 546 | if (destroy_mark) |
4712e722 | 547 | fsnotify_detach_mark(fsn_mark); |
7b18527c | 548 | mutex_unlock(&group->mark_mutex); |
4712e722 JK |
549 | if (destroy_mark) |
550 | fsnotify_free_mark(fsn_mark); | |
6dfbd149 | 551 | |
f3640192 | 552 | fsnotify_put_mark(fsn_mark); |
f3640192 AG |
553 | return 0; |
554 | } | |
2a3edf86 | 555 | |
f3640192 | 556 | static int fanotify_remove_inode_mark(struct fsnotify_group *group, |
b9e4e3bd EP |
557 | struct inode *inode, __u32 mask, |
558 | unsigned int flags) | |
f3640192 AG |
559 | { |
560 | struct fsnotify_mark *fsn_mark = NULL; | |
561 | __u32 removed; | |
6dfbd149 | 562 | int destroy_mark; |
f3640192 | 563 | |
7b18527c | 564 | mutex_lock(&group->mark_mutex); |
f3640192 | 565 | fsn_mark = fsnotify_find_inode_mark(group, inode); |
7b18527c LS |
566 | if (!fsn_mark) { |
567 | mutex_unlock(&group->mark_mutex); | |
88826276 | 568 | return -ENOENT; |
7b18527c | 569 | } |
88826276 | 570 | |
6dfbd149 LS |
571 | removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags, |
572 | &destroy_mark); | |
c9747640 | 573 | if (removed & inode->i_fsnotify_mask) |
8920d273 | 574 | fsnotify_recalc_mask(inode->i_fsnotify_marks); |
6dfbd149 | 575 | if (destroy_mark) |
4712e722 | 576 | fsnotify_detach_mark(fsn_mark); |
7b18527c | 577 | mutex_unlock(&group->mark_mutex); |
4712e722 JK |
578 | if (destroy_mark) |
579 | fsnotify_free_mark(fsn_mark); | |
7b18527c | 580 | |
5444e298 | 581 | /* matches the fsnotify_find_inode_mark() */ |
2a3edf86 | 582 | fsnotify_put_mark(fsn_mark); |
088b09b0 | 583 | |
2a3edf86 EP |
584 | return 0; |
585 | } | |
586 | ||
b9e4e3bd EP |
587 | static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark, |
588 | __u32 mask, | |
589 | unsigned int flags) | |
912ee394 | 590 | { |
192ca4d1 | 591 | __u32 oldmask = -1; |
912ee394 AG |
592 | |
593 | spin_lock(&fsn_mark->lock); | |
b9e4e3bd | 594 | if (!(flags & FAN_MARK_IGNORED_MASK)) { |
66ba93c0 LS |
595 | __u32 tmask = fsn_mark->mask | mask; |
596 | ||
597 | if (flags & FAN_MARK_ONDIR) | |
598 | tmask |= FAN_ONDIR; | |
599 | ||
b9e4e3bd | 600 | oldmask = fsn_mark->mask; |
66d2b81b | 601 | fsn_mark->mask = tmask; |
b9e4e3bd | 602 | } else { |
192ca4d1 | 603 | __u32 tmask = fsn_mark->ignored_mask | mask; |
66ba93c0 LS |
604 | if (flags & FAN_MARK_ONDIR) |
605 | tmask |= FAN_ONDIR; | |
606 | ||
66d2b81b | 607 | fsn_mark->ignored_mask = tmask; |
c9778a98 EP |
608 | if (flags & FAN_MARK_IGNORED_SURV_MODIFY) |
609 | fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY; | |
b9e4e3bd | 610 | } |
912ee394 AG |
611 | spin_unlock(&fsn_mark->lock); |
612 | ||
613 | return mask & ~oldmask; | |
614 | } | |
615 | ||
5e9c070c LS |
616 | static struct fsnotify_mark *fanotify_add_new_mark(struct fsnotify_group *group, |
617 | struct inode *inode, | |
618 | struct vfsmount *mnt) | |
619 | { | |
620 | struct fsnotify_mark *mark; | |
621 | int ret; | |
622 | ||
623 | if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks) | |
624 | return ERR_PTR(-ENOSPC); | |
625 | ||
626 | mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL); | |
627 | if (!mark) | |
628 | return ERR_PTR(-ENOMEM); | |
629 | ||
630 | fsnotify_init_mark(mark, fanotify_free_mark); | |
631 | ret = fsnotify_add_mark_locked(mark, group, inode, mnt, 0); | |
632 | if (ret) { | |
633 | fsnotify_put_mark(mark); | |
634 | return ERR_PTR(ret); | |
635 | } | |
636 | ||
637 | return mark; | |
638 | } | |
639 | ||
640 | ||
52202dfb | 641 | static int fanotify_add_vfsmount_mark(struct fsnotify_group *group, |
b9e4e3bd EP |
642 | struct vfsmount *mnt, __u32 mask, |
643 | unsigned int flags) | |
2a3edf86 EP |
644 | { |
645 | struct fsnotify_mark *fsn_mark; | |
912ee394 | 646 | __u32 added; |
2a3edf86 | 647 | |
7b18527c | 648 | mutex_lock(&group->mark_mutex); |
88826276 EP |
649 | fsn_mark = fsnotify_find_vfsmount_mark(group, mnt); |
650 | if (!fsn_mark) { | |
5e9c070c LS |
651 | fsn_mark = fanotify_add_new_mark(group, NULL, mnt); |
652 | if (IS_ERR(fsn_mark)) { | |
7b18527c | 653 | mutex_unlock(&group->mark_mutex); |
5e9c070c | 654 | return PTR_ERR(fsn_mark); |
7b18527c | 655 | } |
88826276 | 656 | } |
b9e4e3bd | 657 | added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); |
c63181e6 | 658 | if (added & ~real_mount(mnt)->mnt_fsnotify_mask) |
8920d273 | 659 | fsnotify_recalc_mask(real_mount(mnt)->mnt_fsnotify_marks); |
c9747640 | 660 | mutex_unlock(&group->mark_mutex); |
5e9c070c | 661 | |
fa218ab9 | 662 | fsnotify_put_mark(fsn_mark); |
5e9c070c | 663 | return 0; |
88826276 EP |
664 | } |
665 | ||
52202dfb | 666 | static int fanotify_add_inode_mark(struct fsnotify_group *group, |
b9e4e3bd EP |
667 | struct inode *inode, __u32 mask, |
668 | unsigned int flags) | |
88826276 EP |
669 | { |
670 | struct fsnotify_mark *fsn_mark; | |
912ee394 | 671 | __u32 added; |
88826276 EP |
672 | |
673 | pr_debug("%s: group=%p inode=%p\n", __func__, group, inode); | |
2a3edf86 | 674 | |
5322a59f EP |
675 | /* |
676 | * If some other task has this inode open for write we should not add | |
677 | * an ignored mark, unless that ignored mark is supposed to survive | |
678 | * modification changes anyway. | |
679 | */ | |
680 | if ((flags & FAN_MARK_IGNORED_MASK) && | |
681 | !(flags & FAN_MARK_IGNORED_SURV_MODIFY) && | |
682 | (atomic_read(&inode->i_writecount) > 0)) | |
683 | return 0; | |
684 | ||
7b18527c | 685 | mutex_lock(&group->mark_mutex); |
5444e298 | 686 | fsn_mark = fsnotify_find_inode_mark(group, inode); |
2a3edf86 | 687 | if (!fsn_mark) { |
5e9c070c LS |
688 | fsn_mark = fanotify_add_new_mark(group, inode, NULL); |
689 | if (IS_ERR(fsn_mark)) { | |
7b18527c | 690 | mutex_unlock(&group->mark_mutex); |
5e9c070c | 691 | return PTR_ERR(fsn_mark); |
7b18527c | 692 | } |
2a3edf86 | 693 | } |
b9e4e3bd | 694 | added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); |
43709a28 | 695 | if (added & ~inode->i_fsnotify_mask) |
8920d273 | 696 | fsnotify_recalc_mask(inode->i_fsnotify_marks); |
c9747640 | 697 | mutex_unlock(&group->mark_mutex); |
5e9c070c | 698 | |
fa218ab9 | 699 | fsnotify_put_mark(fsn_mark); |
5e9c070c | 700 | return 0; |
88826276 | 701 | } |
2a3edf86 | 702 | |
52c923dd | 703 | /* fanotify syscalls */ |
08ae8938 | 704 | SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) |
11637e4b | 705 | { |
52c923dd EP |
706 | struct fsnotify_group *group; |
707 | int f_flags, fd; | |
4afeff85 | 708 | struct user_struct *user; |
ff57cd58 | 709 | struct fanotify_event_info *oevent; |
52c923dd | 710 | |
08ae8938 EP |
711 | pr_debug("%s: flags=%d event_f_flags=%d\n", |
712 | __func__, flags, event_f_flags); | |
52c923dd | 713 | |
52c923dd | 714 | if (!capable(CAP_SYS_ADMIN)) |
a2f13ad0 | 715 | return -EPERM; |
52c923dd EP |
716 | |
717 | if (flags & ~FAN_ALL_INIT_FLAGS) | |
718 | return -EINVAL; | |
719 | ||
48149e9d HS |
720 | if (event_f_flags & ~FANOTIFY_INIT_ALL_EVENT_F_BITS) |
721 | return -EINVAL; | |
722 | ||
723 | switch (event_f_flags & O_ACCMODE) { | |
724 | case O_RDONLY: | |
725 | case O_RDWR: | |
726 | case O_WRONLY: | |
727 | break; | |
728 | default: | |
729 | return -EINVAL; | |
730 | } | |
731 | ||
4afeff85 EP |
732 | user = get_current_user(); |
733 | if (atomic_read(&user->fanotify_listeners) > FANOTIFY_DEFAULT_MAX_LISTENERS) { | |
734 | free_uid(user); | |
735 | return -EMFILE; | |
736 | } | |
737 | ||
b2d87909 | 738 | f_flags = O_RDWR | FMODE_NONOTIFY; |
52c923dd EP |
739 | if (flags & FAN_CLOEXEC) |
740 | f_flags |= O_CLOEXEC; | |
741 | if (flags & FAN_NONBLOCK) | |
742 | f_flags |= O_NONBLOCK; | |
743 | ||
744 | /* fsnotify_alloc_group takes a ref. Dropped in fanotify_release */ | |
745 | group = fsnotify_alloc_group(&fanotify_fsnotify_ops); | |
26379198 EP |
746 | if (IS_ERR(group)) { |
747 | free_uid(user); | |
52c923dd | 748 | return PTR_ERR(group); |
26379198 | 749 | } |
52c923dd | 750 | |
4afeff85 EP |
751 | group->fanotify_data.user = user; |
752 | atomic_inc(&user->fanotify_listeners); | |
753 | ||
f083441b | 754 | oevent = fanotify_alloc_event(NULL, FS_Q_OVERFLOW, NULL); |
ff57cd58 JK |
755 | if (unlikely(!oevent)) { |
756 | fd = -ENOMEM; | |
757 | goto out_destroy_group; | |
758 | } | |
759 | group->overflow_event = &oevent->fse; | |
ff57cd58 | 760 | |
1e2ee49f WW |
761 | if (force_o_largefile()) |
762 | event_f_flags |= O_LARGEFILE; | |
80af2588 | 763 | group->fanotify_data.f_flags = event_f_flags; |
9e66e423 | 764 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
9e66e423 EP |
765 | init_waitqueue_head(&group->fanotify_data.access_waitq); |
766 | INIT_LIST_HEAD(&group->fanotify_data.access_list); | |
767 | #endif | |
4231a235 EP |
768 | switch (flags & FAN_ALL_CLASS_BITS) { |
769 | case FAN_CLASS_NOTIF: | |
770 | group->priority = FS_PRIO_0; | |
771 | break; | |
772 | case FAN_CLASS_CONTENT: | |
773 | group->priority = FS_PRIO_1; | |
774 | break; | |
775 | case FAN_CLASS_PRE_CONTENT: | |
776 | group->priority = FS_PRIO_2; | |
777 | break; | |
778 | default: | |
779 | fd = -EINVAL; | |
d8153d4d | 780 | goto out_destroy_group; |
4231a235 | 781 | } |
cb2d429f | 782 | |
5dd03f55 EP |
783 | if (flags & FAN_UNLIMITED_QUEUE) { |
784 | fd = -EPERM; | |
785 | if (!capable(CAP_SYS_ADMIN)) | |
d8153d4d | 786 | goto out_destroy_group; |
5dd03f55 EP |
787 | group->max_events = UINT_MAX; |
788 | } else { | |
789 | group->max_events = FANOTIFY_DEFAULT_MAX_EVENTS; | |
790 | } | |
2529a0df | 791 | |
ac7e22dc EP |
792 | if (flags & FAN_UNLIMITED_MARKS) { |
793 | fd = -EPERM; | |
794 | if (!capable(CAP_SYS_ADMIN)) | |
d8153d4d | 795 | goto out_destroy_group; |
ac7e22dc EP |
796 | group->fanotify_data.max_marks = UINT_MAX; |
797 | } else { | |
798 | group->fanotify_data.max_marks = FANOTIFY_DEFAULT_MAX_MARKS; | |
799 | } | |
e7099d8a | 800 | |
52c923dd EP |
801 | fd = anon_inode_getfd("[fanotify]", &fanotify_fops, group, f_flags); |
802 | if (fd < 0) | |
d8153d4d | 803 | goto out_destroy_group; |
52c923dd EP |
804 | |
805 | return fd; | |
806 | ||
d8153d4d LS |
807 | out_destroy_group: |
808 | fsnotify_destroy_group(group); | |
52c923dd | 809 | return fd; |
11637e4b | 810 | } |
bbaa4168 | 811 | |
4a0fd5bf AV |
812 | SYSCALL_DEFINE5(fanotify_mark, int, fanotify_fd, unsigned int, flags, |
813 | __u64, mask, int, dfd, | |
814 | const char __user *, pathname) | |
bbaa4168 | 815 | { |
0ff21db9 EP |
816 | struct inode *inode = NULL; |
817 | struct vfsmount *mnt = NULL; | |
2a3edf86 | 818 | struct fsnotify_group *group; |
2903ff01 | 819 | struct fd f; |
2a3edf86 | 820 | struct path path; |
2903ff01 | 821 | int ret; |
2a3edf86 EP |
822 | |
823 | pr_debug("%s: fanotify_fd=%d flags=%x dfd=%d pathname=%p mask=%llx\n", | |
824 | __func__, fanotify_fd, flags, dfd, pathname, mask); | |
825 | ||
826 | /* we only use the lower 32 bits as of right now. */ | |
827 | if (mask & ((__u64)0xffffffff << 32)) | |
828 | return -EINVAL; | |
829 | ||
88380fe6 AG |
830 | if (flags & ~FAN_ALL_MARK_FLAGS) |
831 | return -EINVAL; | |
4d92604c | 832 | switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) { |
1734dee4 | 833 | case FAN_MARK_ADD: /* fallthrough */ |
88380fe6 | 834 | case FAN_MARK_REMOVE: |
1734dee4 LS |
835 | if (!mask) |
836 | return -EINVAL; | |
cc299a98 | 837 | break; |
4d92604c | 838 | case FAN_MARK_FLUSH: |
cc299a98 HS |
839 | if (flags & ~(FAN_MARK_MOUNT | FAN_MARK_FLUSH)) |
840 | return -EINVAL; | |
88380fe6 AG |
841 | break; |
842 | default: | |
843 | return -EINVAL; | |
844 | } | |
8fcd6528 EP |
845 | |
846 | if (mask & FAN_ONDIR) { | |
847 | flags |= FAN_MARK_ONDIR; | |
848 | mask &= ~FAN_ONDIR; | |
849 | } | |
850 | ||
b2d87909 EP |
851 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
852 | if (mask & ~(FAN_ALL_EVENTS | FAN_ALL_PERM_EVENTS | FAN_EVENT_ON_CHILD)) | |
853 | #else | |
88380fe6 | 854 | if (mask & ~(FAN_ALL_EVENTS | FAN_EVENT_ON_CHILD)) |
b2d87909 | 855 | #endif |
2a3edf86 EP |
856 | return -EINVAL; |
857 | ||
2903ff01 AV |
858 | f = fdget(fanotify_fd); |
859 | if (unlikely(!f.file)) | |
2a3edf86 EP |
860 | return -EBADF; |
861 | ||
862 | /* verify that this is indeed an fanotify instance */ | |
863 | ret = -EINVAL; | |
2903ff01 | 864 | if (unlikely(f.file->f_op != &fanotify_fops)) |
2a3edf86 | 865 | goto fput_and_out; |
2903ff01 | 866 | group = f.file->private_data; |
4231a235 EP |
867 | |
868 | /* | |
869 | * group->priority == FS_PRIO_0 == FAN_CLASS_NOTIF. These are not | |
870 | * allowed to set permissions events. | |
871 | */ | |
872 | ret = -EINVAL; | |
873 | if (mask & FAN_ALL_PERM_EVENTS && | |
874 | group->priority == FS_PRIO_0) | |
875 | goto fput_and_out; | |
2a3edf86 | 876 | |
0a8dd2db HS |
877 | if (flags & FAN_MARK_FLUSH) { |
878 | ret = 0; | |
879 | if (flags & FAN_MARK_MOUNT) | |
880 | fsnotify_clear_vfsmount_marks_by_group(group); | |
881 | else | |
882 | fsnotify_clear_inode_marks_by_group(group); | |
883 | goto fput_and_out; | |
884 | } | |
885 | ||
2a3edf86 EP |
886 | ret = fanotify_find_path(dfd, pathname, &path, flags); |
887 | if (ret) | |
888 | goto fput_and_out; | |
889 | ||
890 | /* inode held in place by reference to path; group by fget on fd */ | |
eac8e9e8 | 891 | if (!(flags & FAN_MARK_MOUNT)) |
0ff21db9 EP |
892 | inode = path.dentry->d_inode; |
893 | else | |
894 | mnt = path.mnt; | |
2a3edf86 EP |
895 | |
896 | /* create/update an inode mark */ | |
0a8dd2db | 897 | switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE)) { |
c6223f46 | 898 | case FAN_MARK_ADD: |
eac8e9e8 | 899 | if (flags & FAN_MARK_MOUNT) |
b9e4e3bd | 900 | ret = fanotify_add_vfsmount_mark(group, mnt, mask, flags); |
0ff21db9 | 901 | else |
b9e4e3bd | 902 | ret = fanotify_add_inode_mark(group, inode, mask, flags); |
c6223f46 AG |
903 | break; |
904 | case FAN_MARK_REMOVE: | |
f3640192 | 905 | if (flags & FAN_MARK_MOUNT) |
b9e4e3bd | 906 | ret = fanotify_remove_vfsmount_mark(group, mnt, mask, flags); |
f3640192 | 907 | else |
b9e4e3bd | 908 | ret = fanotify_remove_inode_mark(group, inode, mask, flags); |
c6223f46 AG |
909 | break; |
910 | default: | |
911 | ret = -EINVAL; | |
912 | } | |
2a3edf86 EP |
913 | |
914 | path_put(&path); | |
915 | fput_and_out: | |
2903ff01 | 916 | fdput(f); |
2a3edf86 EP |
917 | return ret; |
918 | } | |
919 | ||
91c2e0bc AV |
920 | #ifdef CONFIG_COMPAT |
921 | COMPAT_SYSCALL_DEFINE6(fanotify_mark, | |
922 | int, fanotify_fd, unsigned int, flags, | |
923 | __u32, mask0, __u32, mask1, int, dfd, | |
924 | const char __user *, pathname) | |
925 | { | |
926 | return sys_fanotify_mark(fanotify_fd, flags, | |
927 | #ifdef __BIG_ENDIAN | |
91c2e0bc | 928 | ((__u64)mask0 << 32) | mask1, |
592f6b84 HC |
929 | #else |
930 | ((__u64)mask1 << 32) | mask0, | |
91c2e0bc AV |
931 | #endif |
932 | dfd, pathname); | |
933 | } | |
934 | #endif | |
935 | ||
2a3edf86 | 936 | /* |
ae0e47f0 | 937 | * fanotify_user_setup - Our initialization function. Note that we cannot return |
2a3edf86 EP |
938 | * error because we have compiled-in VFS hooks. So an (unlikely) failure here |
939 | * must result in panic(). | |
940 | */ | |
941 | static int __init fanotify_user_setup(void) | |
942 | { | |
943 | fanotify_mark_cache = KMEM_CACHE(fsnotify_mark, SLAB_PANIC); | |
7053aee2 | 944 | fanotify_event_cachep = KMEM_CACHE(fanotify_event_info, SLAB_PANIC); |
f083441b JK |
945 | #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS |
946 | fanotify_perm_event_cachep = KMEM_CACHE(fanotify_perm_event_info, | |
947 | SLAB_PANIC); | |
948 | #endif | |
2a3edf86 EP |
949 | |
950 | return 0; | |
bbaa4168 | 951 | } |
2a3edf86 | 952 | device_initcall(fanotify_user_setup); |