blob: d43803669739df471e8e832ced4377f6f75ab015 [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
Andreas Gruenbacher22aa4252009-12-17 21:24:26 -050061static int create_fd(struct fsnotify_group *group, struct fsnotify_event *event)
Eric Parisa1014f12009-12-17 21:24:26 -050062{
63 int client_fd;
Eric Parisa1014f12009-12-17 21:24:26 -050064 struct file *new_file;
65
Andreas Gruenbacher22aa4252009-12-17 21:24:26 -050066 pr_debug("%s: group=%p event=%p\n", __func__, group, event);
Eric Parisa1014f12009-12-17 21:24:26 -050067
68 client_fd = get_unused_fd();
69 if (client_fd < 0)
70 return client_fd;
71
Linus Torvalds20696012010-08-12 14:23:04 -070072 if (event->data_type != FSNOTIFY_EVENT_PATH) {
Eric Parisa1014f12009-12-17 21:24:26 -050073 WARN_ON(1);
74 put_unused_fd(client_fd);
75 return -EINVAL;
76 }
77
78 /*
79 * we need a new file handle for the userspace program so it can read even if it was
80 * originally opened O_WRONLY.
81 */
Eric Parisa1014f12009-12-17 21:24:26 -050082 /* it's possible this event was an overflow event. in that case dentry and mnt
83 * are NULL; That's fine, just don't call dentry open */
Al Viro765927b2012-06-26 21:58:53 +040084 if (event->path.dentry && event->path.mnt)
85 new_file = dentry_open(&event->path,
Eric Paris80af2582010-07-28 10:18:37 -040086 group->fanotify_data.f_flags | FMODE_NONOTIFY,
Eric Parisa1014f12009-12-17 21:24:26 -050087 current_cred());
88 else
89 new_file = ERR_PTR(-EOVERFLOW);
90 if (IS_ERR(new_file)) {
91 /*
92 * we still send an event even if we can't open the file. this
93 * can happen when say tasks are gone and we try to open their
94 * /proc files or we try to open a WRONLY file like in sysfs
95 * we just send the errno to userspace since there isn't much
96 * else we can do.
97 */
98 put_unused_fd(client_fd);
99 client_fd = PTR_ERR(new_file);
100 } else {
101 fd_install(client_fd, new_file);
102 }
103
Andreas Gruenbacher22aa4252009-12-17 21:24:26 -0500104 return client_fd;
Eric Parisa1014f12009-12-17 21:24:26 -0500105}
106
Eric Parisecf6f5e2010-11-08 18:08:14 -0500107static int fill_event_metadata(struct fsnotify_group *group,
Eric Parisa1014f12009-12-17 21:24:26 -0500108 struct fanotify_event_metadata *metadata,
109 struct fsnotify_event *event)
110{
Lino Sanfilippofdbf3ce2010-11-24 18:26:04 +0100111 int ret = 0;
112
Eric Parisa1014f12009-12-17 21:24:26 -0500113 pr_debug("%s: group=%p metadata=%p event=%p\n", __func__,
114 group, metadata, event);
115
116 metadata->event_len = FAN_EVENT_METADATA_LEN;
Eric Paris7d131622010-12-07 15:27:57 -0500117 metadata->metadata_len = FAN_EVENT_METADATA_LEN;
Eric Parisa1014f12009-12-17 21:24:26 -0500118 metadata->vers = FANOTIFY_METADATA_VERSION;
Andreas Gruenbacher33d3dff2009-12-17 21:24:29 -0500119 metadata->mask = event->mask & FAN_ALL_OUTGOING_EVENTS;
Andreas Gruenbacher32c32632009-12-17 21:24:27 -0500120 metadata->pid = pid_vnr(event->tgid);
Lino Sanfilippofdbf3ce2010-11-24 18:26:04 +0100121 if (unlikely(event->mask & FAN_Q_OVERFLOW))
122 metadata->fd = FAN_NOFD;
123 else {
124 metadata->fd = create_fd(group, event);
125 if (metadata->fd < 0)
126 ret = metadata->fd;
127 }
Eric Parisa1014f12009-12-17 21:24:26 -0500128
Lino Sanfilippofdbf3ce2010-11-24 18:26:04 +0100129 return ret;
Eric Parisa1014f12009-12-17 21:24:26 -0500130}
131
Eric Parisb2d87902009-12-17 21:24:34 -0500132#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
133static struct fanotify_response_event *dequeue_re(struct fsnotify_group *group,
134 __s32 fd)
135{
136 struct fanotify_response_event *re, *return_re = NULL;
137
138 mutex_lock(&group->fanotify_data.access_mutex);
139 list_for_each_entry(re, &group->fanotify_data.access_list, list) {
140 if (re->fd != fd)
141 continue;
142
143 list_del_init(&re->list);
144 return_re = re;
145 break;
146 }
147 mutex_unlock(&group->fanotify_data.access_mutex);
148
149 pr_debug("%s: found return_re=%p\n", __func__, return_re);
150
151 return return_re;
152}
153
154static int process_access_response(struct fsnotify_group *group,
155 struct fanotify_response *response_struct)
156{
157 struct fanotify_response_event *re;
158 __s32 fd = response_struct->fd;
159 __u32 response = response_struct->response;
160
161 pr_debug("%s: group=%p fd=%d response=%d\n", __func__, group,
162 fd, response);
163 /*
164 * make sure the response is valid, if invalid we do nothing and either
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300165 * userspace can send a valid response or we will clean it up after the
Eric Parisb2d87902009-12-17 21:24:34 -0500166 * timeout
167 */
168 switch (response) {
169 case FAN_ALLOW:
170 case FAN_DENY:
171 break;
172 default:
173 return -EINVAL;
174 }
175
176 if (fd < 0)
177 return -EINVAL;
178
179 re = dequeue_re(group, fd);
180 if (!re)
181 return -ENOENT;
182
183 re->event->response = response;
184
185 wake_up(&group->fanotify_data.access_waitq);
186
187 kmem_cache_free(fanotify_response_event_cache, re);
188
189 return 0;
190}
191
192static int prepare_for_access_response(struct fsnotify_group *group,
193 struct fsnotify_event *event,
194 __s32 fd)
195{
196 struct fanotify_response_event *re;
197
198 if (!(event->mask & FAN_ALL_PERM_EVENTS))
199 return 0;
200
201 re = kmem_cache_alloc(fanotify_response_event_cache, GFP_KERNEL);
202 if (!re)
203 return -ENOMEM;
204
205 re->event = event;
206 re->fd = fd;
207
208 mutex_lock(&group->fanotify_data.access_mutex);
Eric Paris2eebf582010-08-18 12:25:50 -0400209
Lino Sanfilippo09e5f142010-11-19 10:58:07 +0100210 if (atomic_read(&group->fanotify_data.bypass_perm)) {
Eric Paris2eebf582010-08-18 12:25:50 -0400211 mutex_unlock(&group->fanotify_data.access_mutex);
212 kmem_cache_free(fanotify_response_event_cache, re);
213 event->response = FAN_ALLOW;
214 return 0;
215 }
216
Eric Parisb2d87902009-12-17 21:24:34 -0500217 list_add_tail(&re->list, &group->fanotify_data.access_list);
218 mutex_unlock(&group->fanotify_data.access_mutex);
219
220 return 0;
221}
222
223static void remove_access_response(struct fsnotify_group *group,
224 struct fsnotify_event *event,
225 __s32 fd)
226{
227 struct fanotify_response_event *re;
228
229 if (!(event->mask & FAN_ALL_PERM_EVENTS))
230 return;
231
232 re = dequeue_re(group, fd);
233 if (!re)
234 return;
235
236 BUG_ON(re->event != event);
237
238 kmem_cache_free(fanotify_response_event_cache, re);
239
240 return;
241}
242#else
243static int prepare_for_access_response(struct fsnotify_group *group,
244 struct fsnotify_event *event,
245 __s32 fd)
246{
247 return 0;
248}
249
250static void remove_access_response(struct fsnotify_group *group,
251 struct fsnotify_event *event,
252 __s32 fd)
253{
Eric Paris8860f062009-12-23 00:10:25 -0500254 return;
Eric Parisb2d87902009-12-17 21:24:34 -0500255}
256#endif
257
Eric Parisa1014f12009-12-17 21:24:26 -0500258static ssize_t copy_event_to_user(struct fsnotify_group *group,
259 struct fsnotify_event *event,
260 char __user *buf)
261{
262 struct fanotify_event_metadata fanotify_event_metadata;
Eric Parisb2d87902009-12-17 21:24:34 -0500263 int fd, ret;
Eric Parisa1014f12009-12-17 21:24:26 -0500264
265 pr_debug("%s: group=%p event=%p\n", __func__, group, event);
266
Eric Parisecf6f5e2010-11-08 18:08:14 -0500267 ret = fill_event_metadata(group, &fanotify_event_metadata, event);
268 if (ret < 0)
269 goto out;
Eric Parisa1014f12009-12-17 21:24:26 -0500270
Lino Sanfilippofdbf3ce2010-11-24 18:26:04 +0100271 fd = fanotify_event_metadata.fd;
Eric Parisb2d87902009-12-17 21:24:34 -0500272 ret = prepare_for_access_response(group, event, fd);
273 if (ret)
274 goto out_close_fd;
275
276 ret = -EFAULT;
Eric Paris7d131622010-12-07 15:27:57 -0500277 if (copy_to_user(buf, &fanotify_event_metadata,
278 fanotify_event_metadata.event_len))
Eric Parisb2d87902009-12-17 21:24:34 -0500279 goto out_kill_access_response;
Eric Parisa1014f12009-12-17 21:24:26 -0500280
Eric Paris7d131622010-12-07 15:27:57 -0500281 return fanotify_event_metadata.event_len;
Eric Parisb2d87902009-12-17 21:24:34 -0500282
283out_kill_access_response:
284 remove_access_response(group, event, fd);
285out_close_fd:
Lino Sanfilippofdbf3ce2010-11-24 18:26:04 +0100286 if (fd != FAN_NOFD)
287 sys_close(fd);
Eric Parisecf6f5e2010-11-08 18:08:14 -0500288out:
289#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
290 if (event->mask & FAN_ALL_PERM_EVENTS) {
291 event->response = FAN_DENY;
292 wake_up(&group->fanotify_data.access_waitq);
293 }
294#endif
Eric Parisb2d87902009-12-17 21:24:34 -0500295 return ret;
Eric Parisa1014f12009-12-17 21:24:26 -0500296}
297
298/* intofiy userspace file descriptor functions */
299static unsigned int fanotify_poll(struct file *file, poll_table *wait)
300{
301 struct fsnotify_group *group = file->private_data;
302 int ret = 0;
303
304 poll_wait(file, &group->notification_waitq, wait);
305 mutex_lock(&group->notification_mutex);
306 if (!fsnotify_notify_queue_is_empty(group))
307 ret = POLLIN | POLLRDNORM;
308 mutex_unlock(&group->notification_mutex);
309
310 return ret;
311}
312
313static ssize_t fanotify_read(struct file *file, char __user *buf,
314 size_t count, loff_t *pos)
315{
316 struct fsnotify_group *group;
317 struct fsnotify_event *kevent;
318 char __user *start;
319 int ret;
320 DEFINE_WAIT(wait);
321
322 start = buf;
323 group = file->private_data;
324
325 pr_debug("%s: group=%p\n", __func__, group);
326
327 while (1) {
328 prepare_to_wait(&group->notification_waitq, &wait, TASK_INTERRUPTIBLE);
329
330 mutex_lock(&group->notification_mutex);
331 kevent = get_one_event(group, count);
332 mutex_unlock(&group->notification_mutex);
333
334 if (kevent) {
335 ret = PTR_ERR(kevent);
336 if (IS_ERR(kevent))
337 break;
338 ret = copy_event_to_user(group, kevent, buf);
339 fsnotify_put_event(kevent);
340 if (ret < 0)
341 break;
342 buf += ret;
343 count -= ret;
344 continue;
345 }
346
347 ret = -EAGAIN;
348 if (file->f_flags & O_NONBLOCK)
349 break;
Lino Sanfilippo1a5cea72010-10-29 12:06:42 +0200350 ret = -ERESTARTSYS;
Eric Parisa1014f12009-12-17 21:24:26 -0500351 if (signal_pending(current))
352 break;
353
354 if (start != buf)
355 break;
356
357 schedule();
358 }
359
360 finish_wait(&group->notification_waitq, &wait);
361 if (start != buf && ret != -EFAULT)
362 ret = buf - start;
363 return ret;
364}
365
Eric Parisb2d87902009-12-17 21:24:34 -0500366static ssize_t fanotify_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)
367{
368#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
369 struct fanotify_response response = { .fd = -1, .response = -1 };
370 struct fsnotify_group *group;
371 int ret;
372
373 group = file->private_data;
374
375 if (count > sizeof(response))
376 count = sizeof(response);
377
378 pr_debug("%s: group=%p count=%zu\n", __func__, group, count);
379
380 if (copy_from_user(&response, buf, count))
381 return -EFAULT;
382
383 ret = process_access_response(group, &response);
384 if (ret < 0)
385 count = ret;
386
387 return count;
388#else
389 return -EINVAL;
390#endif
391}
392
Eric Paris52c923d2009-12-17 21:24:26 -0500393static int fanotify_release(struct inode *ignored, struct file *file)
394{
395 struct fsnotify_group *group = file->private_data;
Eric Paris52c923d2009-12-17 21:24:26 -0500396
Eric Paris2eebf582010-08-18 12:25:50 -0400397#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
Andrew Morton19ba54f2010-10-28 17:21:59 -0400398 struct fanotify_response_event *re, *lre;
399
Eric Paris2eebf582010-08-18 12:25:50 -0400400 mutex_lock(&group->fanotify_data.access_mutex);
401
Lino Sanfilippo09e5f142010-11-19 10:58:07 +0100402 atomic_inc(&group->fanotify_data.bypass_perm);
Eric Paris2eebf582010-08-18 12:25:50 -0400403
404 list_for_each_entry_safe(re, lre, &group->fanotify_data.access_list, list) {
405 pr_debug("%s: found group=%p re=%p event=%p\n", __func__, group,
406 re, re->event);
407
408 list_del_init(&re->list);
409 re->event->response = FAN_ALLOW;
410
411 kmem_cache_free(fanotify_response_event_cache, re);
412 }
413 mutex_unlock(&group->fanotify_data.access_mutex);
414
415 wake_up(&group->fanotify_data.access_waitq);
416#endif
Eric Paris52c923d2009-12-17 21:24:26 -0500417 /* matches the fanotify_init->fsnotify_alloc_group */
418 fsnotify_put_group(group);
419
420 return 0;
421}
422
Eric Parisa1014f12009-12-17 21:24:26 -0500423static long fanotify_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
424{
425 struct fsnotify_group *group;
426 struct fsnotify_event_holder *holder;
427 void __user *p;
428 int ret = -ENOTTY;
429 size_t send_len = 0;
430
431 group = file->private_data;
432
433 p = (void __user *) arg;
434
435 switch (cmd) {
436 case FIONREAD:
437 mutex_lock(&group->notification_mutex);
438 list_for_each_entry(holder, &group->notification_list, event_list)
439 send_len += FAN_EVENT_METADATA_LEN;
440 mutex_unlock(&group->notification_mutex);
441 ret = put_user(send_len, (int __user *) p);
442 break;
443 }
444
445 return ret;
446}
447
Eric Paris52c923d2009-12-17 21:24:26 -0500448static const struct file_operations fanotify_fops = {
Eric Parisa1014f12009-12-17 21:24:26 -0500449 .poll = fanotify_poll,
450 .read = fanotify_read,
Eric Parisb2d87902009-12-17 21:24:34 -0500451 .write = fanotify_write,
Eric Paris52c923d2009-12-17 21:24:26 -0500452 .fasync = NULL,
453 .release = fanotify_release,
Eric Parisa1014f12009-12-17 21:24:26 -0500454 .unlocked_ioctl = fanotify_ioctl,
455 .compat_ioctl = fanotify_ioctl,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200456 .llseek = noop_llseek,
Eric Paris52c923d2009-12-17 21:24:26 -0500457};
458
Eric Paris2a3edf82009-12-17 21:24:26 -0500459static void fanotify_free_mark(struct fsnotify_mark *fsn_mark)
460{
461 kmem_cache_free(fanotify_mark_cache, fsn_mark);
462}
463
464static int fanotify_find_path(int dfd, const char __user *filename,
465 struct path *path, unsigned int flags)
466{
467 int ret;
468
469 pr_debug("%s: dfd=%d filename=%p flags=%x\n", __func__,
470 dfd, filename, flags);
471
472 if (filename == NULL) {
473 struct file *file;
474 int fput_needed;
475
476 ret = -EBADF;
477 file = fget_light(dfd, &fput_needed);
478 if (!file)
479 goto out;
480
481 ret = -ENOTDIR;
482 if ((flags & FAN_MARK_ONLYDIR) &&
483 !(S_ISDIR(file->f_path.dentry->d_inode->i_mode))) {
484 fput_light(file, fput_needed);
485 goto out;
486 }
487
488 *path = file->f_path;
489 path_get(path);
490 fput_light(file, fput_needed);
491 } else {
492 unsigned int lookup_flags = 0;
493
494 if (!(flags & FAN_MARK_DONT_FOLLOW))
495 lookup_flags |= LOOKUP_FOLLOW;
496 if (flags & FAN_MARK_ONLYDIR)
497 lookup_flags |= LOOKUP_DIRECTORY;
498
499 ret = user_path_at(dfd, filename, lookup_flags, path);
500 if (ret)
501 goto out;
502 }
503
504 /* you can only watch an inode if you have read permissions on it */
505 ret = inode_permission(path->dentry->d_inode, MAY_READ);
506 if (ret)
507 path_put(path);
508out:
509 return ret;
510}
511
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500512static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark,
513 __u32 mask,
514 unsigned int flags)
Andreas Gruenbacher088b09b2009-12-17 21:24:28 -0500515{
516 __u32 oldmask;
517
518 spin_lock(&fsn_mark->lock);
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500519 if (!(flags & FAN_MARK_IGNORED_MASK)) {
520 oldmask = fsn_mark->mask;
521 fsnotify_set_mark_mask_locked(fsn_mark, (oldmask & ~mask));
522 } else {
523 oldmask = fsn_mark->ignored_mask;
524 fsnotify_set_mark_ignored_mask_locked(fsn_mark, (oldmask & ~mask));
525 }
Andreas Gruenbacher088b09b2009-12-17 21:24:28 -0500526 spin_unlock(&fsn_mark->lock);
527
528 if (!(oldmask & ~mask))
529 fsnotify_destroy_mark(fsn_mark);
530
531 return mask & oldmask;
532}
533
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500534static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group,
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500535 struct vfsmount *mnt, __u32 mask,
536 unsigned int flags)
Eric Paris88826272009-12-17 21:24:28 -0500537{
538 struct fsnotify_mark *fsn_mark = NULL;
Andreas Gruenbacher088b09b2009-12-17 21:24:28 -0500539 __u32 removed;
Eric Paris88826272009-12-17 21:24:28 -0500540
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500541 fsn_mark = fsnotify_find_vfsmount_mark(group, mnt);
542 if (!fsn_mark)
543 return -ENOENT;
Eric Paris88826272009-12-17 21:24:28 -0500544
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500545 removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags);
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500546 fsnotify_put_mark(fsn_mark);
Al Viroc63181e2011-11-25 02:35:16 -0500547 if (removed & real_mount(mnt)->mnt_fsnotify_mask)
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500548 fsnotify_recalc_vfsmount_mask(mnt);
Eric Paris88826272009-12-17 21:24:28 -0500549
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500550 return 0;
551}
552
553static int fanotify_remove_inode_mark(struct fsnotify_group *group,
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500554 struct inode *inode, __u32 mask,
555 unsigned int flags)
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500556{
557 struct fsnotify_mark *fsn_mark = NULL;
558 __u32 removed;
559
560 fsn_mark = fsnotify_find_inode_mark(group, inode);
Eric Paris88826272009-12-17 21:24:28 -0500561 if (!fsn_mark)
562 return -ENOENT;
563
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500564 removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags);
Eric Paris5444e292009-12-17 21:24:27 -0500565 /* matches the fsnotify_find_inode_mark() */
Eric Paris2a3edf82009-12-17 21:24:26 -0500566 fsnotify_put_mark(fsn_mark);
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500567 if (removed & inode->i_fsnotify_mask)
568 fsnotify_recalc_inode_mask(inode);
Andreas Gruenbacher088b09b2009-12-17 21:24:28 -0500569
Eric Paris2a3edf82009-12-17 21:24:26 -0500570 return 0;
571}
572
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500573static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark,
574 __u32 mask,
575 unsigned int flags)
Andreas Gruenbacher912ee392009-12-17 21:24:28 -0500576{
Eric Paris192ca4d2010-10-28 17:21:59 -0400577 __u32 oldmask = -1;
Andreas Gruenbacher912ee392009-12-17 21:24:28 -0500578
579 spin_lock(&fsn_mark->lock);
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500580 if (!(flags & FAN_MARK_IGNORED_MASK)) {
581 oldmask = fsn_mark->mask;
582 fsnotify_set_mark_mask_locked(fsn_mark, (oldmask | mask));
583 } else {
Eric Paris192ca4d2010-10-28 17:21:59 -0400584 __u32 tmask = fsn_mark->ignored_mask | mask;
585 fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask);
Eric Parisc9778a92009-12-17 21:24:33 -0500586 if (flags & FAN_MARK_IGNORED_SURV_MODIFY)
587 fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY;
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500588 }
Eric Paris8fcd6522010-10-28 17:21:59 -0400589
590 if (!(flags & FAN_MARK_ONDIR)) {
591 __u32 tmask = fsn_mark->ignored_mask | FAN_ONDIR;
592 fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask);
593 }
594
Andreas Gruenbacher912ee392009-12-17 21:24:28 -0500595 spin_unlock(&fsn_mark->lock);
596
597 return mask & ~oldmask;
598}
599
Andreas Gruenbacher52202df2009-12-17 21:24:28 -0500600static int fanotify_add_vfsmount_mark(struct fsnotify_group *group,
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500601 struct vfsmount *mnt, __u32 mask,
602 unsigned int flags)
Eric Paris2a3edf82009-12-17 21:24:26 -0500603{
604 struct fsnotify_mark *fsn_mark;
Andreas Gruenbacher912ee392009-12-17 21:24:28 -0500605 __u32 added;
Lino Sanfilippofa218ab2010-11-09 18:18:16 +0100606 int ret = 0;
Eric Paris2a3edf82009-12-17 21:24:26 -0500607
Eric Paris88826272009-12-17 21:24:28 -0500608 fsn_mark = fsnotify_find_vfsmount_mark(group, mnt);
609 if (!fsn_mark) {
Eric Parise7099d82010-10-28 17:21:57 -0400610 if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks)
611 return -ENOSPC;
612
Andreas Gruenbacher912ee392009-12-17 21:24:28 -0500613 fsn_mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL);
614 if (!fsn_mark)
Andreas Gruenbacher52202df2009-12-17 21:24:28 -0500615 return -ENOMEM;
Eric Paris88826272009-12-17 21:24:28 -0500616
Andreas Gruenbacher912ee392009-12-17 21:24:28 -0500617 fsnotify_init_mark(fsn_mark, fanotify_free_mark);
618 ret = fsnotify_add_mark(fsn_mark, group, NULL, mnt, 0);
Lino Sanfilippofa218ab2010-11-09 18:18:16 +0100619 if (ret)
620 goto err;
Eric Paris88826272009-12-17 21:24:28 -0500621 }
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500622 added = fanotify_mark_add_to_mask(fsn_mark, mask, flags);
Lino Sanfilippofa218ab2010-11-09 18:18:16 +0100623
Al Viroc63181e2011-11-25 02:35:16 -0500624 if (added & ~real_mount(mnt)->mnt_fsnotify_mask)
Eric Paris43709a22010-07-28 10:18:39 -0400625 fsnotify_recalc_vfsmount_mask(mnt);
Lino Sanfilippofa218ab2010-11-09 18:18:16 +0100626err:
627 fsnotify_put_mark(fsn_mark);
628 return ret;
Eric Paris88826272009-12-17 21:24:28 -0500629}
630
Andreas Gruenbacher52202df2009-12-17 21:24:28 -0500631static int fanotify_add_inode_mark(struct fsnotify_group *group,
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500632 struct inode *inode, __u32 mask,
633 unsigned int flags)
Eric Paris88826272009-12-17 21:24:28 -0500634{
635 struct fsnotify_mark *fsn_mark;
Andreas Gruenbacher912ee392009-12-17 21:24:28 -0500636 __u32 added;
Lino Sanfilippofa218ab2010-11-09 18:18:16 +0100637 int ret = 0;
Eric Paris88826272009-12-17 21:24:28 -0500638
639 pr_debug("%s: group=%p inode=%p\n", __func__, group, inode);
Eric Paris2a3edf82009-12-17 21:24:26 -0500640
Eric Paris5322a592010-10-28 17:21:57 -0400641 /*
642 * If some other task has this inode open for write we should not add
643 * an ignored mark, unless that ignored mark is supposed to survive
644 * modification changes anyway.
645 */
646 if ((flags & FAN_MARK_IGNORED_MASK) &&
647 !(flags & FAN_MARK_IGNORED_SURV_MODIFY) &&
648 (atomic_read(&inode->i_writecount) > 0))
649 return 0;
650
Eric Paris5444e292009-12-17 21:24:27 -0500651 fsn_mark = fsnotify_find_inode_mark(group, inode);
Eric Paris2a3edf82009-12-17 21:24:26 -0500652 if (!fsn_mark) {
Eric Parise7099d82010-10-28 17:21:57 -0400653 if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks)
654 return -ENOSPC;
655
Andreas Gruenbacher912ee392009-12-17 21:24:28 -0500656 fsn_mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL);
657 if (!fsn_mark)
Andreas Gruenbacher52202df2009-12-17 21:24:28 -0500658 return -ENOMEM;
Eric Paris2a3edf82009-12-17 21:24:26 -0500659
Andreas Gruenbacher912ee392009-12-17 21:24:28 -0500660 fsnotify_init_mark(fsn_mark, fanotify_free_mark);
661 ret = fsnotify_add_mark(fsn_mark, group, inode, NULL, 0);
Lino Sanfilippofa218ab2010-11-09 18:18:16 +0100662 if (ret)
663 goto err;
Eric Paris2a3edf82009-12-17 21:24:26 -0500664 }
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500665 added = fanotify_mark_add_to_mask(fsn_mark, mask, flags);
Lino Sanfilippofa218ab2010-11-09 18:18:16 +0100666
Eric Paris43709a22010-07-28 10:18:39 -0400667 if (added & ~inode->i_fsnotify_mask)
668 fsnotify_recalc_inode_mask(inode);
Lino Sanfilippofa218ab2010-11-09 18:18:16 +0100669err:
670 fsnotify_put_mark(fsn_mark);
671 return ret;
Eric Paris88826272009-12-17 21:24:28 -0500672}
Eric Paris2a3edf82009-12-17 21:24:26 -0500673
Eric Paris52c923d2009-12-17 21:24:26 -0500674/* fanotify syscalls */
Eric Paris08ae8932010-05-27 09:41:40 -0400675SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
Eric Paris11637e42009-12-17 21:24:25 -0500676{
Eric Paris52c923d2009-12-17 21:24:26 -0500677 struct fsnotify_group *group;
678 int f_flags, fd;
Eric Paris4afeff82010-10-28 17:21:58 -0400679 struct user_struct *user;
Eric Paris52c923d2009-12-17 21:24:26 -0500680
Eric Paris08ae8932010-05-27 09:41:40 -0400681 pr_debug("%s: flags=%d event_f_flags=%d\n",
682 __func__, flags, event_f_flags);
Eric Paris52c923d2009-12-17 21:24:26 -0500683
Eric Paris52c923d2009-12-17 21:24:26 -0500684 if (!capable(CAP_SYS_ADMIN))
Andreas Gruenbachera2f13ad2010-08-24 12:58:54 +0200685 return -EPERM;
Eric Paris52c923d2009-12-17 21:24:26 -0500686
687 if (flags & ~FAN_ALL_INIT_FLAGS)
688 return -EINVAL;
689
Eric Paris4afeff82010-10-28 17:21:58 -0400690 user = get_current_user();
691 if (atomic_read(&user->fanotify_listeners) > FANOTIFY_DEFAULT_MAX_LISTENERS) {
692 free_uid(user);
693 return -EMFILE;
694 }
695
Eric Parisb2d87902009-12-17 21:24:34 -0500696 f_flags = O_RDWR | FMODE_NONOTIFY;
Eric Paris52c923d2009-12-17 21:24:26 -0500697 if (flags & FAN_CLOEXEC)
698 f_flags |= O_CLOEXEC;
699 if (flags & FAN_NONBLOCK)
700 f_flags |= O_NONBLOCK;
701
702 /* fsnotify_alloc_group takes a ref. Dropped in fanotify_release */
703 group = fsnotify_alloc_group(&fanotify_fsnotify_ops);
Eric Paris263791982010-11-23 23:48:26 -0500704 if (IS_ERR(group)) {
705 free_uid(user);
Eric Paris52c923d2009-12-17 21:24:26 -0500706 return PTR_ERR(group);
Eric Paris263791982010-11-23 23:48:26 -0500707 }
Eric Paris52c923d2009-12-17 21:24:26 -0500708
Eric Paris4afeff82010-10-28 17:21:58 -0400709 group->fanotify_data.user = user;
710 atomic_inc(&user->fanotify_listeners);
711
Eric Paris80af2582010-07-28 10:18:37 -0400712 group->fanotify_data.f_flags = event_f_flags;
Eric Paris9e66e422009-12-17 21:24:34 -0500713#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
714 mutex_init(&group->fanotify_data.access_mutex);
715 init_waitqueue_head(&group->fanotify_data.access_waitq);
716 INIT_LIST_HEAD(&group->fanotify_data.access_list);
Lino Sanfilippo09e5f142010-11-19 10:58:07 +0100717 atomic_set(&group->fanotify_data.bypass_perm, 0);
Eric Paris9e66e422009-12-17 21:24:34 -0500718#endif
Eric Paris4231a232010-10-28 17:21:56 -0400719 switch (flags & FAN_ALL_CLASS_BITS) {
720 case FAN_CLASS_NOTIF:
721 group->priority = FS_PRIO_0;
722 break;
723 case FAN_CLASS_CONTENT:
724 group->priority = FS_PRIO_1;
725 break;
726 case FAN_CLASS_PRE_CONTENT:
727 group->priority = FS_PRIO_2;
728 break;
729 default:
730 fd = -EINVAL;
731 goto out_put_group;
732 }
Eric Pariscb2d4292009-12-17 21:24:34 -0500733
Eric Paris5dd03f52010-10-28 17:21:57 -0400734 if (flags & FAN_UNLIMITED_QUEUE) {
735 fd = -EPERM;
736 if (!capable(CAP_SYS_ADMIN))
737 goto out_put_group;
738 group->max_events = UINT_MAX;
739 } else {
740 group->max_events = FANOTIFY_DEFAULT_MAX_EVENTS;
741 }
Eric Paris2529a0d2010-10-28 17:21:57 -0400742
Eric Parisac7e22d2010-10-28 17:21:58 -0400743 if (flags & FAN_UNLIMITED_MARKS) {
744 fd = -EPERM;
745 if (!capable(CAP_SYS_ADMIN))
746 goto out_put_group;
747 group->fanotify_data.max_marks = UINT_MAX;
748 } else {
749 group->fanotify_data.max_marks = FANOTIFY_DEFAULT_MAX_MARKS;
750 }
Eric Parise7099d82010-10-28 17:21:57 -0400751
Eric Paris52c923d2009-12-17 21:24:26 -0500752 fd = anon_inode_getfd("[fanotify]", &fanotify_fops, group, f_flags);
753 if (fd < 0)
754 goto out_put_group;
755
756 return fd;
757
758out_put_group:
759 fsnotify_put_group(group);
760 return fd;
Eric Paris11637e42009-12-17 21:24:25 -0500761}
Eric Parisbbaa4162009-12-17 21:24:26 -0500762
Heiko Carstens9bbfc962009-12-17 21:24:26 -0500763SYSCALL_DEFINE(fanotify_mark)(int fanotify_fd, unsigned int flags,
764 __u64 mask, int dfd,
765 const char __user * pathname)
Eric Parisbbaa4162009-12-17 21:24:26 -0500766{
Eric Paris0ff21db2009-12-17 21:24:29 -0500767 struct inode *inode = NULL;
768 struct vfsmount *mnt = NULL;
Eric Paris2a3edf82009-12-17 21:24:26 -0500769 struct fsnotify_group *group;
770 struct file *filp;
771 struct path path;
772 int ret, fput_needed;
773
774 pr_debug("%s: fanotify_fd=%d flags=%x dfd=%d pathname=%p mask=%llx\n",
775 __func__, fanotify_fd, flags, dfd, pathname, mask);
776
777 /* we only use the lower 32 bits as of right now. */
778 if (mask & ((__u64)0xffffffff << 32))
779 return -EINVAL;
780
Andreas Gruenbacher88380fe2009-12-17 21:24:29 -0500781 if (flags & ~FAN_ALL_MARK_FLAGS)
782 return -EINVAL;
Eric Paris4d926042009-12-17 21:24:34 -0500783 switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) {
Lino Sanfilippo1734dee2010-11-22 18:46:33 +0100784 case FAN_MARK_ADD: /* fallthrough */
Andreas Gruenbacher88380fe2009-12-17 21:24:29 -0500785 case FAN_MARK_REMOVE:
Lino Sanfilippo1734dee2010-11-22 18:46:33 +0100786 if (!mask)
787 return -EINVAL;
Eric Paris4d926042009-12-17 21:24:34 -0500788 case FAN_MARK_FLUSH:
Andreas Gruenbacher88380fe2009-12-17 21:24:29 -0500789 break;
790 default:
791 return -EINVAL;
792 }
Eric Paris8fcd6522010-10-28 17:21:59 -0400793
794 if (mask & FAN_ONDIR) {
795 flags |= FAN_MARK_ONDIR;
796 mask &= ~FAN_ONDIR;
797 }
798
Eric Parisb2d87902009-12-17 21:24:34 -0500799#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
800 if (mask & ~(FAN_ALL_EVENTS | FAN_ALL_PERM_EVENTS | FAN_EVENT_ON_CHILD))
801#else
Andreas Gruenbacher88380fe2009-12-17 21:24:29 -0500802 if (mask & ~(FAN_ALL_EVENTS | FAN_EVENT_ON_CHILD))
Eric Parisb2d87902009-12-17 21:24:34 -0500803#endif
Eric Paris2a3edf82009-12-17 21:24:26 -0500804 return -EINVAL;
805
806 filp = fget_light(fanotify_fd, &fput_needed);
807 if (unlikely(!filp))
808 return -EBADF;
809
810 /* verify that this is indeed an fanotify instance */
811 ret = -EINVAL;
812 if (unlikely(filp->f_op != &fanotify_fops))
813 goto fput_and_out;
Eric Paris4231a232010-10-28 17:21:56 -0400814 group = filp->private_data;
815
816 /*
817 * group->priority == FS_PRIO_0 == FAN_CLASS_NOTIF. These are not
818 * allowed to set permissions events.
819 */
820 ret = -EINVAL;
821 if (mask & FAN_ALL_PERM_EVENTS &&
822 group->priority == FS_PRIO_0)
823 goto fput_and_out;
Eric Paris2a3edf82009-12-17 21:24:26 -0500824
825 ret = fanotify_find_path(dfd, pathname, &path, flags);
826 if (ret)
827 goto fput_and_out;
828
829 /* inode held in place by reference to path; group by fget on fd */
Andreas Gruenbachereac8e9e2009-12-17 21:24:29 -0500830 if (!(flags & FAN_MARK_MOUNT))
Eric Paris0ff21db2009-12-17 21:24:29 -0500831 inode = path.dentry->d_inode;
832 else
833 mnt = path.mnt;
Eric Paris2a3edf82009-12-17 21:24:26 -0500834
835 /* create/update an inode mark */
Eric Paris4d926042009-12-17 21:24:34 -0500836 switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) {
Andreas Gruenbacherc6223f42009-12-17 21:24:28 -0500837 case FAN_MARK_ADD:
Andreas Gruenbachereac8e9e2009-12-17 21:24:29 -0500838 if (flags & FAN_MARK_MOUNT)
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500839 ret = fanotify_add_vfsmount_mark(group, mnt, mask, flags);
Eric Paris0ff21db2009-12-17 21:24:29 -0500840 else
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500841 ret = fanotify_add_inode_mark(group, inode, mask, flags);
Andreas Gruenbacherc6223f42009-12-17 21:24:28 -0500842 break;
843 case FAN_MARK_REMOVE:
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500844 if (flags & FAN_MARK_MOUNT)
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500845 ret = fanotify_remove_vfsmount_mark(group, mnt, mask, flags);
Andreas Gruenbacherf3640192009-12-17 21:24:29 -0500846 else
Eric Parisb9e4e3b2009-12-17 21:24:33 -0500847 ret = fanotify_remove_inode_mark(group, inode, mask, flags);
Andreas Gruenbacherc6223f42009-12-17 21:24:28 -0500848 break;
Eric Paris4d926042009-12-17 21:24:34 -0500849 case FAN_MARK_FLUSH:
850 if (flags & FAN_MARK_MOUNT)
851 fsnotify_clear_vfsmount_marks_by_group(group);
852 else
853 fsnotify_clear_inode_marks_by_group(group);
Eric Paris4d926042009-12-17 21:24:34 -0500854 break;
Andreas Gruenbacherc6223f42009-12-17 21:24:28 -0500855 default:
856 ret = -EINVAL;
857 }
Eric Paris2a3edf82009-12-17 21:24:26 -0500858
859 path_put(&path);
860fput_and_out:
861 fput_light(filp, fput_needed);
862 return ret;
Eric Parisbbaa4162009-12-17 21:24:26 -0500863}
Eric Paris2a3edf82009-12-17 21:24:26 -0500864
Heiko Carstens9bbfc962009-12-17 21:24:26 -0500865#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
866asmlinkage long SyS_fanotify_mark(long fanotify_fd, long flags, __u64 mask,
867 long dfd, long pathname)
868{
869 return SYSC_fanotify_mark((int) fanotify_fd, (unsigned int) flags,
870 mask, (int) dfd,
871 (const char __user *) pathname);
872}
873SYSCALL_ALIAS(sys_fanotify_mark, SyS_fanotify_mark);
874#endif
875
Eric Paris2a3edf82009-12-17 21:24:26 -0500876/*
Justin P. Mattockae0e47f2011-03-01 15:06:02 +0100877 * fanotify_user_setup - Our initialization function. Note that we cannot return
Eric Paris2a3edf82009-12-17 21:24:26 -0500878 * error because we have compiled-in VFS hooks. So an (unlikely) failure here
879 * must result in panic().
880 */
881static int __init fanotify_user_setup(void)
882{
883 fanotify_mark_cache = KMEM_CACHE(fsnotify_mark, SLAB_PANIC);
Eric Parisb2d87902009-12-17 21:24:34 -0500884 fanotify_response_event_cache = KMEM_CACHE(fanotify_response_event,
885 SLAB_PANIC);
Eric Paris2a3edf82009-12-17 21:24:26 -0500886
887 return 0;
888}
889device_initcall(fanotify_user_setup);