blob: 6fcaeb8c902e4c3bc862c6c81db0a884068274b7 [file] [log] [blame]
Andreas Gruenbacher33d3dff2009-12-17 21:24:29 -05001#include <linux/fanotify.h>
Eric Paris11637e42009-12-17 21:24:25 -05002#include <linux/fcntl.h>
Eric Paris2a3edf82009-12-17 21:24:26 -05003#include <linux/file.h>
Eric Paris11637e42009-12-17 21:24:25 -05004#include <linux/fs.h>
Eric Paris52c923d2009-12-17 21:24:26 -05005#include <linux/anon_inodes.h>
Eric Paris11637e42009-12-17 21:24:25 -05006#include <linux/fsnotify_backend.h>
Eric Paris2a3edf82009-12-17 21:24:26 -05007#include <linux/init.h>
Eric Parisa1014f12009-12-17 21:24:26 -05008#include <linux/mount.h>
Eric Paris2a3edf82009-12-17 21:24:26 -05009#include <linux/namei.h>
Eric Parisa1014f12009-12-17 21:24:26 -050010#include <linux/poll.h>
Eric Paris11637e42009-12-17 21:24:25 -050011#include <linux/security.h>
12#include <linux/syscalls.h>
Tejun Heoe4e047a2010-05-20 01:36:28 +100013#include <linux/slab.h>
Eric Paris2a3edf82009-12-17 21:24:26 -050014#include <linux/types.h>
Eric Parisa1014f12009-12-17 21:24:26 -050015#include <linux/uaccess.h>
16
17#include <asm/ioctls.h>
Eric Paris11637e42009-12-17 21:24:25 -050018
Al Viroc63181e2011-11-25 02:35:16 -050019#include "../../mount.h"
20
Eric Paris2529a0d2010-10-28 17:21:57 -040021#define FANOTIFY_DEFAULT_MAX_EVENTS 16384
Eric Parise7099d82010-10-28 17:21:57 -040022#define FANOTIFY_DEFAULT_MAX_MARKS 8192
Eric Paris4afeff82010-10-28 17:21:58 -040023#define FANOTIFY_DEFAULT_MAX_LISTENERS 128
Eric Paris2529a0d2010-10-28 17:21:57 -040024
Andreas Gruenbacher33d3dff2009-12-17 21:24:29 -050025extern const struct fsnotify_ops fanotify_fsnotify_ops;
Eric Paris11637e42009-12-17 21:24:25 -050026
Eric Paris2a3edf82009-12-17 21:24:26 -050027static struct kmem_cache *fanotify_mark_cache __read_mostly;
Eric Parisb2d87902009-12-17 21:24:34 -050028static struct kmem_cache *fanotify_response_event_cache __read_mostly;
29
30struct fanotify_response_event {
31 struct list_head list;
32 __s32 fd;
33 struct fsnotify_event *event;
34};
Eric Paris2a3edf82009-12-17 21:24:26 -050035
Eric Parisa1014f12009-12-17 21:24:26 -050036/*
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 */
43static 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
Al Viro352e3b22012-08-19 12:30:45 -040061static int create_fd(struct fsnotify_group *group,
62 struct fsnotify_event *event,
63 struct file **file)
Eric Parisa1014f12009-12-17 21:24:26 -050064{
65 int client_fd;
Eric Parisa1014f12009-12-17 21:24:26 -050066 struct file *new_file;
67
Andreas Gruenbacher22aa4252009-12-17 21:24:26 -050068 pr_debug("%s: group=%p event=%p\n", __func__, group, event);
Eric Parisa1014f12009-12-17 21:24:26 -050069
70 client_fd = get_unused_fd();
71 if (client_fd < 0)
72 return client_fd;
73
Linus Torvalds20696012010-08-12 14:23:04 -070074 if (event->data_type != FSNOTIFY_EVENT_PATH) {
Eric Parisa1014f12009-12-17 21:24:26 -050075 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 */
Eric Parisa1014f12009-12-17 21:24:26 -050084 /* 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 */
Al Viro765927b2012-06-26 21:58:53 +040086 if (event->path.dentry && event->path.mnt)
87 new_file = dentry_open(&event->path,
Eric Paris80af2582010-07-28 10:18:37 -040088 group->fanotify_data.f_flags | FMODE_NONOTIFY,
Eric Parisa1014f12009-12-17 21:24:26 -050089 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 {
Al Viro352e3b22012-08-19 12:30:45 -0400103 *file = new_file;
Eric Parisa1014f12009-12-17 21:24:26 -0500104 }
105
Andreas Gruenbacher22aa4252009-12-17 21:24:26 -0500106 return client_fd;
Eric Parisa1014f12009-12-17 21:24:26 -0500107}
108
Eric Parisecf6f5e2010-11-08 18:08:14 -0500109static int fill_event_metadata(struct fsnotify_group *group,
Eric Parisa1014f12009-12-17 21:24:26 -0500110 struct fanotify_event_metadata *metadata,
Al Viro352e3b22012-08-19 12:30:45 -0400111 struct fsnotify_event *event,
112 struct file **file)
Eric Parisa1014f12009-12-17 21:24:26 -0500113{
Lino Sanfilippofdbf3ce2010-11-24 18:26:04 +0100114 int ret = 0;
115
Eric Parisa1014f12009-12-17 21:24:26 -0500116 pr_debug("%s: group=%p metadata=%p event=%p\n", __func__,
117 group, metadata, event);
118
Al Viro352e3b22012-08-19 12:30:45 -0400119 *file = NULL;
Eric Parisa1014f12009-12-17 21:24:26 -0500120 metadata->event_len = FAN_EVENT_METADATA_LEN;
Eric Paris7d131622010-12-07 15:27:57 -0500121 metadata->metadata_len = FAN_EVENT_METADATA_LEN;
Eric Parisa1014f12009-12-17 21:24:26 -0500122 metadata->vers = FANOTIFY_METADATA_VERSION;
Andreas Gruenbacher33d3dff2009-12-17 21:24:29 -0500123 metadata->mask = event->mask & FAN_ALL_OUTGOING_EVENTS;
Andreas Gruenbacher32c32632009-12-17 21:24:27 -0500124 metadata->pid = pid_vnr(event->tgid);
Lino Sanfilippofdbf3ce2010-11-24 18:26:04 +0100125 if (unlikely(event->mask & FAN_Q_OVERFLOW))
126 metadata->fd = FAN_NOFD;
127 else {
Al Viro352e3b22012-08-19 12:30:45 -0400128 metadata->fd = create_fd(group, event, file);
Lino Sanfilippofdbf3ce2010-11-24 18:26:04 +0100129 if (metadata->fd < 0)
130 ret = metadata->fd;
131 }
Eric Parisa1014f12009-12-17 21:24:26 -0500132
Lino Sanfilippofdbf3ce2010-11-24 18:26:04 +0100133 return ret;
Eric Parisa1014f12009-12-17 21:24:26 -0500134}
135
Eric Parisb2d87902009-12-17 21:24:34 -0500136#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
137static 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
158static 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
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300169 * userspace can send a valid response or we will clean it up after the
Eric Parisb2d87902009-12-17 21:24:34 -0500170 * 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
196static 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);
Eric Paris2eebf582010-08-18 12:25:50 -0400213
Lino Sanfilippo09e5f142010-11-19 10:58:07 +0100214 if (atomic_read(&group->fanotify_data.bypass_perm)) {
Eric Paris2eebf582010-08-18 12:25:50 -0400215 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
Eric Parisb2d87902009-12-17 21:24:34 -0500221 list_add_tail(&re->list, &group->fanotify_data.access_list);
222 mutex_unlock(&group->fanotify_data.access_mutex);
223
224 return 0;
225}
226
Eric Parisb2d87902009-12-17 21:24:34 -0500227#else
228static int prepare_for_access_response(struct fsnotify_group *group,
229 struct fsnotify_event *event,
230 __s32 fd)
231{
232 return 0;
233}
234
Eric Parisb2d87902009-12-17 21:24:34 -0500235#endif
236
Eric Parisa1014f12009-12-17 21:24:26 -0500237static 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;
Al Viro352e3b22012-08-19 12:30:45 -0400242 struct file *f;
Eric Parisb2d87902009-12-17 21:24:34 -0500243 int fd, ret;
Eric Parisa1014f12009-12-17 21:24:26 -0500244
245 pr_debug("%s: group=%p event=%p\n", __func__, group, event);
246
Al Viro352e3b22012-08-19 12:30:45 -0400247 ret = fill_event_metadata(group, &fanotify_event_metadata, event, &f);
Eric Parisecf6f5e2010-11-08 18:08:14 -0500248 if (ret < 0)
249 goto out;
Eric Parisa1014f12009-12-17 21:24:26 -0500250
Lino Sanfilippofdbf3ce2010-11-24 18:26:04 +0100251 fd = fanotify_event_metadata.fd;
Al Viro352e3b22012-08-19 12:30:45 -0400252 ret = -EFAULT;
253 if (copy_to_user(buf, &fanotify_event_metadata,
254 fanotify_event_metadata.event_len))
255 goto out_close_fd;
256
Eric Parisb2d87902009-12-17 21:24:34 -0500257 ret = prepare_for_access_response(group, event, fd);
258 if (ret)
259 goto out_close_fd;
260
Al Viro3587b1b2012-11-18 19:19:00 +0000261 if (fd != FAN_NOFD)
262 fd_install(fd, f);
Eric Paris7d131622010-12-07 15:27:57 -0500263 return fanotify_event_metadata.event_len;
Eric Parisb2d87902009-12-17 21:24:34 -0500264
Eric Parisb2d87902009-12-17 21:24:34 -0500265out_close_fd:
Al Viro352e3b22012-08-19 12:30:45 -0400266 if (fd != FAN_NOFD) {
267 put_unused_fd(fd);
268 fput(f);
269 }
Eric Parisecf6f5e2010-11-08 18:08:14 -0500270out:
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
Eric Parisb2d87902009-12-17 21:24:34 -0500277 return ret;
Eric Parisa1014f12009-12-17 21:24:26 -0500278}
279
280/* intofiy userspace file descriptor functions */
281static 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
295static 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;
Lino Sanfilippo1a5cea72010-10-29 12:06:42 +0200332 ret = -ERESTARTSYS;
Eric Parisa1014f12009-12-17 21:24:26 -0500333 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
Eric Parisb2d87902009-12-17 21:24:34 -0500348static 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
Eric Paris52c923d2009-12-17 21:24:26 -0500375static int fanotify_release(struct inode *ignored, struct file *file)
376{
377 struct fsnotify_group *group = file->private_data;
Eric Paris52c923d2009-12-17 21:24:26 -0500378
Eric Paris2eebf582010-08-18 12:25:50 -0400379#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
Andrew Morton19ba54f2010-10-28 17:21:59 -0400380 struct fanotify_response_event *re, *lre;
381
Eric Paris2eebf582010-08-18 12:25:50 -0400382 mutex_lock(&group->fanotify_data.access_mutex);
383
Lino Sanfilippo09e5f142010-11-19 10:58:07 +0100384 atomic_inc(&group->fanotify_data.bypass_perm);
Eric Paris2eebf582010-08-18 12:25:50 -0400385
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
Eric Paris52c923d2009-12-17 21:24:26 -0500399 /* matches the fanotify_init->fsnotify_alloc_group */
400 fsnotify_put_group(group);
401
402 return 0;
403}
404
Eric Parisa1014f12009-12-17 21:24:26 -0500405static 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
Eric Paris52c923d2009-12-17 21:24:26 -0500430static const struct file_operations fanotify_fops = {
Eric Parisa1014f12009-12-17 21:24:26 -0500431 .poll = fanotify_poll,
432 .read = fanotify_read,
Eric Parisb2d87902009-12-17 21:24:34 -0500433 .write = fanotify_write,
Eric Paris52c923d2009-12-17 21:24:26 -0500434 .fasync = NULL,
435 .release = fanotify_release,
Eric Parisa1014f12009-12-17 21:24:26 -0500436 .unlocked_ioctl = fanotify_ioctl,
437 .compat_ioctl = fanotify_ioctl,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200438 .llseek = noop_llseek,
Eric Paris52c923d2009-12-17 21:24:26 -0500439};
440
Eric Paris2a3edf82009-12-17 21:24:26 -0500441static void fanotify_free_mark(struct fsnotify_mark *fsn_mark)
442{
443 kmem_cache_free(fanotify_mark_cache, fsn_mark);
444}
445
446static 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) {
Al Viro2903ff02012-08-28 12:52:22 -0400455 struct fd f = fdget(dfd);
Eric Paris2a3edf82009-12-17 21:24:26 -0500456
457 ret = -EBADF;
Al Viro2903ff02012-08-28 12:52:22 -0400458 if (!f.file)
Eric Paris2a3edf82009-12-17 21:24:26 -0500459 goto out;
460
461 ret = -ENOTDIR;
462 if ((flags & FAN_MARK_ONLYDIR) &&
Al Viro2903ff02012-08-28 12:52:22 -0400463 !(S_ISDIR(f.file->f_path.dentry->d_inode->i_mode))) {
464 fdput(f);
Eric Paris2a3edf82009-12-17 21:24:26 -0500465 goto out;
466 }
467
Al Viro2903ff02012-08-28 12:52:22 -0400468 *path = f.file->f_path;
Eric Paris2a3edf82009-12-17 21:24:26 -0500469 path_get(path);
Al Viro2903ff02012-08-28 12:52:22 -0400470 fdput(f);
Eric Paris2a3edf82009-12-17 21:24:26 -0500471 } 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);
488out:
489 return ret;
490}
491
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500492static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark,
493 __u32 mask,
494 unsigned int flags)
Andreas Gruenbacher088b09b2009-12-17 21:24:28 -0500495{
496 __u32 oldmask;
497
498 spin_lock(&fsn_mark->lock);
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500499 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 }
Andreas Gruenbacher088b09b2009-12-17 21:24:28 -0500506 spin_unlock(&fsn_mark->lock);
507
508 if (!(oldmask & ~mask))
509 fsnotify_destroy_mark(fsn_mark);
510
511 return mask & oldmask;
512}
513
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500514static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group,
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500515 struct vfsmount *mnt, __u32 mask,
516 unsigned int flags)
Eric Paris88826272009-12-17 21:24:28 -0500517{
518 struct fsnotify_mark *fsn_mark = NULL;
Andreas Gruenbacher088b09b2009-12-17 21:24:28 -0500519 __u32 removed;
Eric Paris88826272009-12-17 21:24:28 -0500520
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500521 fsn_mark = fsnotify_find_vfsmount_mark(group, mnt);
522 if (!fsn_mark)
523 return -ENOENT;
Eric Paris88826272009-12-17 21:24:28 -0500524
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500525 removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags);
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500526 fsnotify_put_mark(fsn_mark);
Al Viroc63181e2011-11-25 02:35:16 -0500527 if (removed & real_mount(mnt)->mnt_fsnotify_mask)
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500528 fsnotify_recalc_vfsmount_mask(mnt);
Eric Paris88826272009-12-17 21:24:28 -0500529
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500530 return 0;
531}
532
533static int fanotify_remove_inode_mark(struct fsnotify_group *group,
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500534 struct inode *inode, __u32 mask,
535 unsigned int flags)
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500536{
537 struct fsnotify_mark *fsn_mark = NULL;
538 __u32 removed;
539
540 fsn_mark = fsnotify_find_inode_mark(group, inode);
Eric Paris88826272009-12-17 21:24:28 -0500541 if (!fsn_mark)
542 return -ENOENT;
543
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500544 removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags);
Eric Paris5444e292009-12-17 21:24:27 -0500545 /* matches the fsnotify_find_inode_mark() */
Eric Paris2a3edf82009-12-17 21:24:26 -0500546 fsnotify_put_mark(fsn_mark);
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500547 if (removed & inode->i_fsnotify_mask)
548 fsnotify_recalc_inode_mask(inode);
Andreas Gruenbacher088b09b2009-12-17 21:24:28 -0500549
Eric Paris2a3edf82009-12-17 21:24:26 -0500550 return 0;
551}
552
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500553static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark,
554 __u32 mask,
555 unsigned int flags)
Andreas Gruenbacher912ee39462009-12-17 21:24:28 -0500556{
Eric Paris192ca4d2010-10-28 17:21:59 -0400557 __u32 oldmask = -1;
Andreas Gruenbacher912ee39462009-12-17 21:24:28 -0500558
559 spin_lock(&fsn_mark->lock);
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500560 if (!(flags & FAN_MARK_IGNORED_MASK)) {
561 oldmask = fsn_mark->mask;
562 fsnotify_set_mark_mask_locked(fsn_mark, (oldmask | mask));
563 } else {
Eric Paris192ca4d2010-10-28 17:21:59 -0400564 __u32 tmask = fsn_mark->ignored_mask | mask;
565 fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask);
Eric Parisc9778a92009-12-17 21:24:33 -0500566 if (flags & FAN_MARK_IGNORED_SURV_MODIFY)
567 fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY;
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500568 }
Eric Paris8fcd6522010-10-28 17:21:59 -0400569
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
Andreas Gruenbacher912ee39462009-12-17 21:24:28 -0500575 spin_unlock(&fsn_mark->lock);
576
577 return mask & ~oldmask;
578}
579
Andreas Gruenbacher52202df2009-12-17 21:24:28 -0500580static int fanotify_add_vfsmount_mark(struct fsnotify_group *group,
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500581 struct vfsmount *mnt, __u32 mask,
582 unsigned int flags)
Eric Paris2a3edf82009-12-17 21:24:26 -0500583{
584 struct fsnotify_mark *fsn_mark;
Andreas Gruenbacher912ee39462009-12-17 21:24:28 -0500585 __u32 added;
Lino Sanfilippofa218ab2010-11-09 18:18:16 +0100586 int ret = 0;
Eric Paris2a3edf82009-12-17 21:24:26 -0500587
Eric Paris88826272009-12-17 21:24:28 -0500588 fsn_mark = fsnotify_find_vfsmount_mark(group, mnt);
589 if (!fsn_mark) {
Eric Parise7099d82010-10-28 17:21:57 -0400590 if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks)
591 return -ENOSPC;
592
Andreas Gruenbacher912ee39462009-12-17 21:24:28 -0500593 fsn_mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL);
594 if (!fsn_mark)
Andreas Gruenbacher52202df2009-12-17 21:24:28 -0500595 return -ENOMEM;
Eric Paris88826272009-12-17 21:24:28 -0500596
Andreas Gruenbacher912ee39462009-12-17 21:24:28 -0500597 fsnotify_init_mark(fsn_mark, fanotify_free_mark);
598 ret = fsnotify_add_mark(fsn_mark, group, NULL, mnt, 0);
Lino Sanfilippofa218ab2010-11-09 18:18:16 +0100599 if (ret)
600 goto err;
Eric Paris88826272009-12-17 21:24:28 -0500601 }
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500602 added = fanotify_mark_add_to_mask(fsn_mark, mask, flags);
Lino Sanfilippofa218ab2010-11-09 18:18:16 +0100603
Al Viroc63181e2011-11-25 02:35:16 -0500604 if (added & ~real_mount(mnt)->mnt_fsnotify_mask)
Eric Paris43709a22010-07-28 10:18:39 -0400605 fsnotify_recalc_vfsmount_mask(mnt);
Lino Sanfilippofa218ab2010-11-09 18:18:16 +0100606err:
607 fsnotify_put_mark(fsn_mark);
608 return ret;
Eric Paris88826272009-12-17 21:24:28 -0500609}
610
Andreas Gruenbacher52202df2009-12-17 21:24:28 -0500611static int fanotify_add_inode_mark(struct fsnotify_group *group,
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500612 struct inode *inode, __u32 mask,
613 unsigned int flags)
Eric Paris88826272009-12-17 21:24:28 -0500614{
615 struct fsnotify_mark *fsn_mark;
Andreas Gruenbacher912ee39462009-12-17 21:24:28 -0500616 __u32 added;
Lino Sanfilippofa218ab2010-11-09 18:18:16 +0100617 int ret = 0;
Eric Paris88826272009-12-17 21:24:28 -0500618
619 pr_debug("%s: group=%p inode=%p\n", __func__, group, inode);
Eric Paris2a3edf82009-12-17 21:24:26 -0500620
Eric Paris5322a592010-10-28 17:21:57 -0400621 /*
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
Eric Paris5444e292009-12-17 21:24:27 -0500631 fsn_mark = fsnotify_find_inode_mark(group, inode);
Eric Paris2a3edf82009-12-17 21:24:26 -0500632 if (!fsn_mark) {
Eric Parise7099d82010-10-28 17:21:57 -0400633 if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks)
634 return -ENOSPC;
635
Andreas Gruenbacher912ee39462009-12-17 21:24:28 -0500636 fsn_mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL);
637 if (!fsn_mark)
Andreas Gruenbacher52202df2009-12-17 21:24:28 -0500638 return -ENOMEM;
Eric Paris2a3edf82009-12-17 21:24:26 -0500639
Andreas Gruenbacher912ee39462009-12-17 21:24:28 -0500640 fsnotify_init_mark(fsn_mark, fanotify_free_mark);
641 ret = fsnotify_add_mark(fsn_mark, group, inode, NULL, 0);
Lino Sanfilippofa218ab2010-11-09 18:18:16 +0100642 if (ret)
643 goto err;
Eric Paris2a3edf82009-12-17 21:24:26 -0500644 }
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500645 added = fanotify_mark_add_to_mask(fsn_mark, mask, flags);
Lino Sanfilippofa218ab2010-11-09 18:18:16 +0100646
Eric Paris43709a22010-07-28 10:18:39 -0400647 if (added & ~inode->i_fsnotify_mask)
648 fsnotify_recalc_inode_mask(inode);
Lino Sanfilippofa218ab2010-11-09 18:18:16 +0100649err:
650 fsnotify_put_mark(fsn_mark);
651 return ret;
Eric Paris88826272009-12-17 21:24:28 -0500652}
Eric Paris2a3edf82009-12-17 21:24:26 -0500653
Eric Paris52c923d2009-12-17 21:24:26 -0500654/* fanotify syscalls */
Eric Paris08ae8932010-05-27 09:41:40 -0400655SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
Eric Paris11637e42009-12-17 21:24:25 -0500656{
Eric Paris52c923d2009-12-17 21:24:26 -0500657 struct fsnotify_group *group;
658 int f_flags, fd;
Eric Paris4afeff82010-10-28 17:21:58 -0400659 struct user_struct *user;
Eric Paris52c923d2009-12-17 21:24:26 -0500660
Eric Paris08ae8932010-05-27 09:41:40 -0400661 pr_debug("%s: flags=%d event_f_flags=%d\n",
662 __func__, flags, event_f_flags);
Eric Paris52c923d2009-12-17 21:24:26 -0500663
Eric Paris52c923d2009-12-17 21:24:26 -0500664 if (!capable(CAP_SYS_ADMIN))
Andreas Gruenbachera2f13ad2010-08-24 12:58:54 +0200665 return -EPERM;
Eric Paris52c923d2009-12-17 21:24:26 -0500666
667 if (flags & ~FAN_ALL_INIT_FLAGS)
668 return -EINVAL;
669
Eric Paris4afeff82010-10-28 17:21:58 -0400670 user = get_current_user();
671 if (atomic_read(&user->fanotify_listeners) > FANOTIFY_DEFAULT_MAX_LISTENERS) {
672 free_uid(user);
673 return -EMFILE;
674 }
675
Eric Parisb2d87902009-12-17 21:24:34 -0500676 f_flags = O_RDWR | FMODE_NONOTIFY;
Eric Paris52c923d2009-12-17 21:24:26 -0500677 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);
Eric Paris26379192010-11-23 23:48:26 -0500684 if (IS_ERR(group)) {
685 free_uid(user);
Eric Paris52c923d2009-12-17 21:24:26 -0500686 return PTR_ERR(group);
Eric Paris26379192010-11-23 23:48:26 -0500687 }
Eric Paris52c923d2009-12-17 21:24:26 -0500688
Eric Paris4afeff82010-10-28 17:21:58 -0400689 group->fanotify_data.user = user;
690 atomic_inc(&user->fanotify_listeners);
691
Eric Paris80af2582010-07-28 10:18:37 -0400692 group->fanotify_data.f_flags = event_f_flags;
Eric Paris9e66e422009-12-17 21:24:34 -0500693#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);
Lino Sanfilippo09e5f142010-11-19 10:58:07 +0100697 atomic_set(&group->fanotify_data.bypass_perm, 0);
Eric Paris9e66e422009-12-17 21:24:34 -0500698#endif
Eric Paris4231a232010-10-28 17:21:56 -0400699 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 }
Eric Pariscb2d4292009-12-17 21:24:34 -0500713
Eric Paris5dd03f52010-10-28 17:21:57 -0400714 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 }
Eric Paris2529a0d2010-10-28 17:21:57 -0400722
Eric Parisac7e22d2010-10-28 17:21:58 -0400723 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 }
Eric Parise7099d82010-10-28 17:21:57 -0400731
Eric Paris52c923d2009-12-17 21:24:26 -0500732 fd = anon_inode_getfd("[fanotify]", &fanotify_fops, group, f_flags);
733 if (fd < 0)
734 goto out_put_group;
735
736 return fd;
737
738out_put_group:
739 fsnotify_put_group(group);
740 return fd;
Eric Paris11637e42009-12-17 21:24:25 -0500741}
Eric Parisbbaa4162009-12-17 21:24:26 -0500742
Heiko Carstens9bbfc962009-12-17 21:24:26 -0500743SYSCALL_DEFINE(fanotify_mark)(int fanotify_fd, unsigned int flags,
744 __u64 mask, int dfd,
745 const char __user * pathname)
Eric Parisbbaa4162009-12-17 21:24:26 -0500746{
Eric Paris0ff21db2009-12-17 21:24:29 -0500747 struct inode *inode = NULL;
748 struct vfsmount *mnt = NULL;
Eric Paris2a3edf82009-12-17 21:24:26 -0500749 struct fsnotify_group *group;
Al Viro2903ff02012-08-28 12:52:22 -0400750 struct fd f;
Eric Paris2a3edf82009-12-17 21:24:26 -0500751 struct path path;
Al Viro2903ff02012-08-28 12:52:22 -0400752 int ret;
Eric Paris2a3edf82009-12-17 21:24:26 -0500753
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
Andreas Gruenbacher88380fe2009-12-17 21:24:29 -0500761 if (flags & ~FAN_ALL_MARK_FLAGS)
762 return -EINVAL;
Eric Paris4d926042009-12-17 21:24:34 -0500763 switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) {
Lino Sanfilippo1734dee2010-11-22 18:46:33 +0100764 case FAN_MARK_ADD: /* fallthrough */
Andreas Gruenbacher88380fe2009-12-17 21:24:29 -0500765 case FAN_MARK_REMOVE:
Lino Sanfilippo1734dee2010-11-22 18:46:33 +0100766 if (!mask)
767 return -EINVAL;
Eric Paris4d926042009-12-17 21:24:34 -0500768 case FAN_MARK_FLUSH:
Andreas Gruenbacher88380fe2009-12-17 21:24:29 -0500769 break;
770 default:
771 return -EINVAL;
772 }
Eric Paris8fcd6522010-10-28 17:21:59 -0400773
774 if (mask & FAN_ONDIR) {
775 flags |= FAN_MARK_ONDIR;
776 mask &= ~FAN_ONDIR;
777 }
778
Eric Parisb2d87902009-12-17 21:24:34 -0500779#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
780 if (mask & ~(FAN_ALL_EVENTS | FAN_ALL_PERM_EVENTS | FAN_EVENT_ON_CHILD))
781#else
Andreas Gruenbacher88380fe2009-12-17 21:24:29 -0500782 if (mask & ~(FAN_ALL_EVENTS | FAN_EVENT_ON_CHILD))
Eric Parisb2d87902009-12-17 21:24:34 -0500783#endif
Eric Paris2a3edf82009-12-17 21:24:26 -0500784 return -EINVAL;
785
Al Viro2903ff02012-08-28 12:52:22 -0400786 f = fdget(fanotify_fd);
787 if (unlikely(!f.file))
Eric Paris2a3edf82009-12-17 21:24:26 -0500788 return -EBADF;
789
790 /* verify that this is indeed an fanotify instance */
791 ret = -EINVAL;
Al Viro2903ff02012-08-28 12:52:22 -0400792 if (unlikely(f.file->f_op != &fanotify_fops))
Eric Paris2a3edf82009-12-17 21:24:26 -0500793 goto fput_and_out;
Al Viro2903ff02012-08-28 12:52:22 -0400794 group = f.file->private_data;
Eric Paris4231a232010-10-28 17:21:56 -0400795
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;
Eric Paris2a3edf82009-12-17 21:24:26 -0500804
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 */
Andreas Gruenbachereac8e9e2009-12-17 21:24:29 -0500810 if (!(flags & FAN_MARK_MOUNT))
Eric Paris0ff21db2009-12-17 21:24:29 -0500811 inode = path.dentry->d_inode;
812 else
813 mnt = path.mnt;
Eric Paris2a3edf82009-12-17 21:24:26 -0500814
815 /* create/update an inode mark */
Eric Paris4d926042009-12-17 21:24:34 -0500816 switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) {
Andreas Gruenbacherc6223f42009-12-17 21:24:28 -0500817 case FAN_MARK_ADD:
Andreas Gruenbachereac8e9e2009-12-17 21:24:29 -0500818 if (flags & FAN_MARK_MOUNT)
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500819 ret = fanotify_add_vfsmount_mark(group, mnt, mask, flags);
Eric Paris0ff21db2009-12-17 21:24:29 -0500820 else
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500821 ret = fanotify_add_inode_mark(group, inode, mask, flags);
Andreas Gruenbacherc6223f42009-12-17 21:24:28 -0500822 break;
823 case FAN_MARK_REMOVE:
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500824 if (flags & FAN_MARK_MOUNT)
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500825 ret = fanotify_remove_vfsmount_mark(group, mnt, mask, flags);
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500826 else
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500827 ret = fanotify_remove_inode_mark(group, inode, mask, flags);
Andreas Gruenbacherc6223f42009-12-17 21:24:28 -0500828 break;
Eric Paris4d926042009-12-17 21:24:34 -0500829 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);
Eric Paris4d926042009-12-17 21:24:34 -0500834 break;
Andreas Gruenbacherc6223f42009-12-17 21:24:28 -0500835 default:
836 ret = -EINVAL;
837 }
Eric Paris2a3edf82009-12-17 21:24:26 -0500838
839 path_put(&path);
840fput_and_out:
Al Viro2903ff02012-08-28 12:52:22 -0400841 fdput(f);
Eric Paris2a3edf82009-12-17 21:24:26 -0500842 return ret;
Eric Parisbbaa4162009-12-17 21:24:26 -0500843}
Eric Paris2a3edf82009-12-17 21:24:26 -0500844
Heiko Carstens9bbfc962009-12-17 21:24:26 -0500845#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
846asmlinkage 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}
853SYSCALL_ALIAS(sys_fanotify_mark, SyS_fanotify_mark);
854#endif
855
Eric Paris2a3edf82009-12-17 21:24:26 -0500856/*
Justin P. Mattockae0e47f2011-03-01 15:06:02 +0100857 * fanotify_user_setup - Our initialization function. Note that we cannot return
Eric Paris2a3edf82009-12-17 21:24:26 -0500858 * error because we have compiled-in VFS hooks. So an (unlikely) failure here
859 * must result in panic().
860 */
861static int __init fanotify_user_setup(void)
862{
863 fanotify_mark_cache = KMEM_CACHE(fsnotify_mark, SLAB_PANIC);
Eric Parisb2d87902009-12-17 21:24:34 -0500864 fanotify_response_event_cache = KMEM_CACHE(fanotify_response_event,
865 SLAB_PANIC);
Eric Paris2a3edf82009-12-17 21:24:26 -0500866
867 return 0;
868}
869device_initcall(fanotify_user_setup);