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1// SPDX-License-Identifier: GPL-2.0
2#include <linux/fanotify.h>
3#include <linux/fcntl.h>
4#include <linux/file.h>
5#include <linux/fs.h>
6#include <linux/anon_inodes.h>
7#include <linux/fsnotify_backend.h>
8#include <linux/init.h>
9#include <linux/mount.h>
10#include <linux/namei.h>
11#include <linux/poll.h>
12#include <linux/security.h>
13#include <linux/syscalls.h>
14#include <linux/slab.h>
15#include <linux/types.h>
16#include <linux/uaccess.h>
17#include <linux/compat.h>
18#include <linux/sched/signal.h>
19
20#include <asm/ioctls.h>
21
22#include "../../mount.h"
23#include "../fdinfo.h"
24#include "fanotify.h"
25
26#define FANOTIFY_DEFAULT_MAX_EVENTS 16384
27#define FANOTIFY_DEFAULT_MAX_MARKS 8192
28#define FANOTIFY_DEFAULT_MAX_LISTENERS 128
29
30/*
31 * All flags that may be specified in parameter event_f_flags of fanotify_init.
32 *
33 * Internal and external open flags are stored together in field f_flags of
34 * struct file. Only external open flags shall be allowed in event_f_flags.
35 * Internal flags like FMODE_NONOTIFY, FMODE_EXEC, FMODE_NOCMTIME shall be
36 * excluded.
37 */
38#define FANOTIFY_INIT_ALL_EVENT_F_BITS ( \
39 O_ACCMODE | O_APPEND | O_NONBLOCK | \
40 __O_SYNC | O_DSYNC | O_CLOEXEC | \
41 O_LARGEFILE | O_NOATIME )
42
43extern const struct fsnotify_ops fanotify_fsnotify_ops;
44
45struct kmem_cache *fanotify_mark_cache __read_mostly;
46struct kmem_cache *fanotify_event_cachep __read_mostly;
47struct kmem_cache *fanotify_perm_event_cachep __read_mostly;
48
49/*
50 * Get an fsnotify notification event if one exists and is small
51 * enough to fit in "count". Return an error pointer if the count
52 * is not large enough.
53 *
54 * Called with the group->notification_lock held.
55 */
56static struct fsnotify_event *get_one_event(struct fsnotify_group *group,
57 size_t count)
58{
59 assert_spin_locked(&group->notification_lock);
60
61 pr_debug("%s: group=%p count=%zd\n", __func__, group, count);
62
63 if (fsnotify_notify_queue_is_empty(group))
64 return NULL;
65
66 if (FAN_EVENT_METADATA_LEN > count)
67 return ERR_PTR(-EINVAL);
68
69 /* held the notification_lock the whole time, so this is the
70 * same event we peeked above */
71 return fsnotify_remove_first_event(group);
72}
73
74static int create_fd(struct fsnotify_group *group,
75 struct fanotify_event_info *event,
76 struct file **file)
77{
78 int client_fd;
79 struct file *new_file;
80
81 pr_debug("%s: group=%p event=%p\n", __func__, group, event);
82
83 client_fd = get_unused_fd_flags(group->fanotify_data.f_flags);
84 if (client_fd < 0)
85 return client_fd;
86
87 /*
88 * we need a new file handle for the userspace program so it can read even if it was
89 * originally opened O_WRONLY.
90 */
91 /* it's possible this event was an overflow event. in that case dentry and mnt
92 * are NULL; That's fine, just don't call dentry open */
93 if (event->path.dentry && event->path.mnt)
94 new_file = dentry_open(&event->path,
95 group->fanotify_data.f_flags | FMODE_NONOTIFY,
96 current_cred());
97 else
98 new_file = ERR_PTR(-EOVERFLOW);
99 if (IS_ERR(new_file)) {
100 /*
101 * we still send an event even if we can't open the file. this
102 * can happen when say tasks are gone and we try to open their
103 * /proc files or we try to open a WRONLY file like in sysfs
104 * we just send the errno to userspace since there isn't much
105 * else we can do.
106 */
107 put_unused_fd(client_fd);
108 client_fd = PTR_ERR(new_file);
109 } else {
110 *file = new_file;
111 }
112
113 return client_fd;
114}
115
116static int fill_event_metadata(struct fsnotify_group *group,
117 struct fanotify_event_metadata *metadata,
118 struct fsnotify_event *fsn_event,
119 struct file **file)
120{
121 int ret = 0;
122 struct fanotify_event_info *event;
123
124 pr_debug("%s: group=%p metadata=%p event=%p\n", __func__,
125 group, metadata, fsn_event);
126
127 *file = NULL;
128 event = container_of(fsn_event, struct fanotify_event_info, fse);
129 metadata->event_len = FAN_EVENT_METADATA_LEN;
130 metadata->metadata_len = FAN_EVENT_METADATA_LEN;
131 metadata->vers = FANOTIFY_METADATA_VERSION;
132 metadata->reserved = 0;
133 metadata->mask = fsn_event->mask & FAN_ALL_OUTGOING_EVENTS;
134 metadata->pid = pid_vnr(event->tgid);
135 if (unlikely(fsn_event->mask & FAN_Q_OVERFLOW))
136 metadata->fd = FAN_NOFD;
137 else {
138 metadata->fd = create_fd(group, event, file);
139 if (metadata->fd < 0)
140 ret = metadata->fd;
141 }
142
143 return ret;
144}
145
146static struct fanotify_perm_event_info *dequeue_event(
147 struct fsnotify_group *group, int fd)
148{
149 struct fanotify_perm_event_info *event, *return_e = NULL;
150
151 spin_lock(&group->notification_lock);
152 list_for_each_entry(event, &group->fanotify_data.access_list,
153 fae.fse.list) {
154 if (event->fd != fd)
155 continue;
156
157 list_del_init(&event->fae.fse.list);
158 return_e = event;
159 break;
160 }
161 spin_unlock(&group->notification_lock);
162
163 pr_debug("%s: found return_re=%p\n", __func__, return_e);
164
165 return return_e;
166}
167
168static int process_access_response(struct fsnotify_group *group,
169 struct fanotify_response *response_struct)
170{
171 struct fanotify_perm_event_info *event;
172 int fd = response_struct->fd;
173 int response = response_struct->response;
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
179 * userspace can send a valid response or we will clean it up after the
180 * timeout
181 */
182 switch (response & ~FAN_AUDIT) {
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
193 if ((response & FAN_AUDIT) && !group->fanotify_data.audit)
194 return -EINVAL;
195
196 event = dequeue_event(group, fd);
197 if (!event)
198 return -ENOENT;
199
200 event->response = response;
201 wake_up(&group->fanotify_data.access_waitq);
202
203 return 0;
204}
205
206static ssize_t copy_event_to_user(struct fsnotify_group *group,
207 struct fsnotify_event *event,
208 char __user *buf)
209{
210 struct fanotify_event_metadata fanotify_event_metadata;
211 struct file *f;
212 int fd, ret;
213
214 pr_debug("%s: group=%p event=%p\n", __func__, group, event);
215
216 ret = fill_event_metadata(group, &fanotify_event_metadata, event, &f);
217 if (ret < 0)
218 return ret;
219
220 fd = fanotify_event_metadata.fd;
221 ret = -EFAULT;
222 if (copy_to_user(buf, &fanotify_event_metadata,
223 fanotify_event_metadata.event_len))
224 goto out_close_fd;
225
226 if (fanotify_is_perm_event(event->mask))
227 FANOTIFY_PE(event)->fd = fd;
228
229 if (fd != FAN_NOFD)
230 fd_install(fd, f);
231 return fanotify_event_metadata.event_len;
232
233out_close_fd:
234 if (fd != FAN_NOFD) {
235 put_unused_fd(fd);
236 fput(f);
237 }
238 return ret;
239}
240
241/* intofiy userspace file descriptor functions */
242static __poll_t fanotify_poll(struct file *file, poll_table *wait)
243{
244 struct fsnotify_group *group = file->private_data;
245 __poll_t ret = 0;
246
247 poll_wait(file, &group->notification_waitq, wait);
248 spin_lock(&group->notification_lock);
249 if (!fsnotify_notify_queue_is_empty(group))
250 ret = EPOLLIN | EPOLLRDNORM;
251 spin_unlock(&group->notification_lock);
252
253 return ret;
254}
255
256static 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;
263 DEFINE_WAIT_FUNC(wait, woken_wake_function);
264
265 start = buf;
266 group = file->private_data;
267
268 pr_debug("%s: group=%p\n", __func__, group);
269
270 add_wait_queue(&group->notification_waitq, &wait);
271 while (1) {
272 spin_lock(&group->notification_lock);
273 kevent = get_one_event(group, count);
274 spin_unlock(&group->notification_lock);
275
276 if (IS_ERR(kevent)) {
277 ret = PTR_ERR(kevent);
278 break;
279 }
280
281 if (!kevent) {
282 ret = -EAGAIN;
283 if (file->f_flags & O_NONBLOCK)
284 break;
285
286 ret = -ERESTARTSYS;
287 if (signal_pending(current))
288 break;
289
290 if (start != buf)
291 break;
292
293 wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
294 continue;
295 }
296
297 ret = copy_event_to_user(group, kevent, buf);
298 if (unlikely(ret == -EOPENSTALE)) {
299 /*
300 * We cannot report events with stale fd so drop it.
301 * Setting ret to 0 will continue the event loop and
302 * do the right thing if there are no more events to
303 * read (i.e. return bytes read, -EAGAIN or wait).
304 */
305 ret = 0;
306 }
307
308 /*
309 * Permission events get queued to wait for response. Other
310 * events can be destroyed now.
311 */
312 if (!fanotify_is_perm_event(kevent->mask)) {
313 fsnotify_destroy_event(group, kevent);
314 } else {
315 if (ret <= 0) {
316 FANOTIFY_PE(kevent)->response = FAN_DENY;
317 wake_up(&group->fanotify_data.access_waitq);
318 } else {
319 spin_lock(&group->notification_lock);
320 list_add_tail(&kevent->list,
321 &group->fanotify_data.access_list);
322 spin_unlock(&group->notification_lock);
323 }
324 }
325 if (ret < 0)
326 break;
327 buf += ret;
328 count -= ret;
329 }
330 remove_wait_queue(&group->notification_waitq, &wait);
331
332 if (start != buf && ret != -EFAULT)
333 ret = buf - start;
334 return ret;
335}
336
337static ssize_t fanotify_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)
338{
339 struct fanotify_response response = { .fd = -1, .response = -1 };
340 struct fsnotify_group *group;
341 int ret;
342
343 if (!IS_ENABLED(CONFIG_FANOTIFY_ACCESS_PERMISSIONS))
344 return -EINVAL;
345
346 group = file->private_data;
347
348 if (count > sizeof(response))
349 count = sizeof(response);
350
351 pr_debug("%s: group=%p count=%zu\n", __func__, group, count);
352
353 if (copy_from_user(&response, buf, count))
354 return -EFAULT;
355
356 ret = process_access_response(group, &response);
357 if (ret < 0)
358 count = ret;
359
360 return count;
361}
362
363static int fanotify_release(struct inode *ignored, struct file *file)
364{
365 struct fsnotify_group *group = file->private_data;
366 struct fanotify_perm_event_info *event, *next;
367 struct fsnotify_event *fsn_event;
368
369 /*
370 * Stop new events from arriving in the notification queue. since
371 * userspace cannot use fanotify fd anymore, no event can enter or
372 * leave access_list by now either.
373 */
374 fsnotify_group_stop_queueing(group);
375
376 /*
377 * Process all permission events on access_list and notification queue
378 * and simulate reply from userspace.
379 */
380 spin_lock(&group->notification_lock);
381 list_for_each_entry_safe(event, next, &group->fanotify_data.access_list,
382 fae.fse.list) {
383 pr_debug("%s: found group=%p event=%p\n", __func__, group,
384 event);
385
386 list_del_init(&event->fae.fse.list);
387 event->response = FAN_ALLOW;
388 }
389
390 /*
391 * Destroy all non-permission events. For permission events just
392 * dequeue them and set the response. They will be freed once the
393 * response is consumed and fanotify_get_response() returns.
394 */
395 while (!fsnotify_notify_queue_is_empty(group)) {
396 fsn_event = fsnotify_remove_first_event(group);
397 if (!(fsn_event->mask & FAN_ALL_PERM_EVENTS)) {
398 spin_unlock(&group->notification_lock);
399 fsnotify_destroy_event(group, fsn_event);
400 spin_lock(&group->notification_lock);
401 } else {
402 FANOTIFY_PE(fsn_event)->response = FAN_ALLOW;
403 }
404 }
405 spin_unlock(&group->notification_lock);
406
407 /* Response for all permission events it set, wakeup waiters */
408 wake_up(&group->fanotify_data.access_waitq);
409
410 /* matches the fanotify_init->fsnotify_alloc_group */
411 fsnotify_destroy_group(group);
412
413 return 0;
414}
415
416static long fanotify_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
417{
418 struct fsnotify_group *group;
419 struct fsnotify_event *fsn_event;
420 void __user *p;
421 int ret = -ENOTTY;
422 size_t send_len = 0;
423
424 group = file->private_data;
425
426 p = (void __user *) arg;
427
428 switch (cmd) {
429 case FIONREAD:
430 spin_lock(&group->notification_lock);
431 list_for_each_entry(fsn_event, &group->notification_list, list)
432 send_len += FAN_EVENT_METADATA_LEN;
433 spin_unlock(&group->notification_lock);
434 ret = put_user(send_len, (int __user *) p);
435 break;
436 }
437
438 return ret;
439}
440
441static const struct file_operations fanotify_fops = {
442 .show_fdinfo = fanotify_show_fdinfo,
443 .poll = fanotify_poll,
444 .read = fanotify_read,
445 .write = fanotify_write,
446 .fasync = NULL,
447 .release = fanotify_release,
448 .unlocked_ioctl = fanotify_ioctl,
449 .compat_ioctl = fanotify_ioctl,
450 .llseek = noop_llseek,
451};
452
453static 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) {
462 struct fd f = fdget(dfd);
463
464 ret = -EBADF;
465 if (!f.file)
466 goto out;
467
468 ret = -ENOTDIR;
469 if ((flags & FAN_MARK_ONLYDIR) &&
470 !(S_ISDIR(file_inode(f.file)->i_mode))) {
471 fdput(f);
472 goto out;
473 }
474
475 *path = f.file->f_path;
476 path_get(path);
477 fdput(f);
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);
495out:
496 return ret;
497}
498
499static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark,
500 __u32 mask,
501 unsigned int flags,
502 int *destroy)
503{
504 __u32 oldmask = 0;
505
506 spin_lock(&fsn_mark->lock);
507 if (!(flags & FAN_MARK_IGNORED_MASK)) {
508 __u32 tmask = fsn_mark->mask & ~mask;
509
510 if (flags & FAN_MARK_ONDIR)
511 tmask &= ~FAN_ONDIR;
512
513 oldmask = fsn_mark->mask;
514 fsn_mark->mask = tmask;
515 } else {
516 __u32 tmask = fsn_mark->ignored_mask & ~mask;
517 if (flags & FAN_MARK_ONDIR)
518 tmask &= ~FAN_ONDIR;
519 fsn_mark->ignored_mask = tmask;
520 }
521 *destroy = !(fsn_mark->mask | fsn_mark->ignored_mask);
522 spin_unlock(&fsn_mark->lock);
523
524 return mask & oldmask;
525}
526
527static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group,
528 struct vfsmount *mnt, __u32 mask,
529 unsigned int flags)
530{
531 struct fsnotify_mark *fsn_mark = NULL;
532 __u32 removed;
533 int destroy_mark;
534
535 mutex_lock(&group->mark_mutex);
536 fsn_mark = fsnotify_find_mark(&real_mount(mnt)->mnt_fsnotify_marks,
537 group);
538 if (!fsn_mark) {
539 mutex_unlock(&group->mark_mutex);
540 return -ENOENT;
541 }
542
543 removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags,
544 &destroy_mark);
545 if (removed & real_mount(mnt)->mnt_fsnotify_mask)
546 fsnotify_recalc_mask(real_mount(mnt)->mnt_fsnotify_marks);
547 if (destroy_mark)
548 fsnotify_detach_mark(fsn_mark);
549 mutex_unlock(&group->mark_mutex);
550 if (destroy_mark)
551 fsnotify_free_mark(fsn_mark);
552
553 fsnotify_put_mark(fsn_mark);
554 return 0;
555}
556
557static int fanotify_remove_inode_mark(struct fsnotify_group *group,
558 struct inode *inode, __u32 mask,
559 unsigned int flags)
560{
561 struct fsnotify_mark *fsn_mark = NULL;
562 __u32 removed;
563 int destroy_mark;
564
565 mutex_lock(&group->mark_mutex);
566 fsn_mark = fsnotify_find_mark(&inode->i_fsnotify_marks, group);
567 if (!fsn_mark) {
568 mutex_unlock(&group->mark_mutex);
569 return -ENOENT;
570 }
571
572 removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags,
573 &destroy_mark);
574 if (removed & inode->i_fsnotify_mask)
575 fsnotify_recalc_mask(inode->i_fsnotify_marks);
576 if (destroy_mark)
577 fsnotify_detach_mark(fsn_mark);
578 mutex_unlock(&group->mark_mutex);
579 if (destroy_mark)
580 fsnotify_free_mark(fsn_mark);
581
582 /* matches the fsnotify_find_mark() */
583 fsnotify_put_mark(fsn_mark);
584
585 return 0;
586}
587
588static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark,
589 __u32 mask,
590 unsigned int flags)
591{
592 __u32 oldmask = -1;
593
594 spin_lock(&fsn_mark->lock);
595 if (!(flags & FAN_MARK_IGNORED_MASK)) {
596 __u32 tmask = fsn_mark->mask | mask;
597
598 if (flags & FAN_MARK_ONDIR)
599 tmask |= FAN_ONDIR;
600
601 oldmask = fsn_mark->mask;
602 fsn_mark->mask = tmask;
603 } else {
604 __u32 tmask = fsn_mark->ignored_mask | mask;
605 if (flags & FAN_MARK_ONDIR)
606 tmask |= FAN_ONDIR;
607
608 fsn_mark->ignored_mask = tmask;
609 if (flags & FAN_MARK_IGNORED_SURV_MODIFY)
610 fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY;
611 }
612 spin_unlock(&fsn_mark->lock);
613
614 return mask & ~oldmask;
615}
616
617static struct fsnotify_mark *fanotify_add_new_mark(struct fsnotify_group *group,
618 struct inode *inode,
619 struct vfsmount *mnt)
620{
621 struct fsnotify_mark *mark;
622 int ret;
623
624 if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks)
625 return ERR_PTR(-ENOSPC);
626
627 mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL);
628 if (!mark)
629 return ERR_PTR(-ENOMEM);
630
631 fsnotify_init_mark(mark, group);
632 ret = fsnotify_add_mark_locked(mark, inode, mnt, 0);
633 if (ret) {
634 fsnotify_put_mark(mark);
635 return ERR_PTR(ret);
636 }
637
638 return mark;
639}
640
641
642static int fanotify_add_vfsmount_mark(struct fsnotify_group *group,
643 struct vfsmount *mnt, __u32 mask,
644 unsigned int flags)
645{
646 struct fsnotify_mark *fsn_mark;
647 __u32 added;
648
649 mutex_lock(&group->mark_mutex);
650 fsn_mark = fsnotify_find_mark(&real_mount(mnt)->mnt_fsnotify_marks,
651 group);
652 if (!fsn_mark) {
653 fsn_mark = fanotify_add_new_mark(group, NULL, mnt);
654 if (IS_ERR(fsn_mark)) {
655 mutex_unlock(&group->mark_mutex);
656 return PTR_ERR(fsn_mark);
657 }
658 }
659 added = fanotify_mark_add_to_mask(fsn_mark, mask, flags);
660 if (added & ~real_mount(mnt)->mnt_fsnotify_mask)
661 fsnotify_recalc_mask(real_mount(mnt)->mnt_fsnotify_marks);
662 mutex_unlock(&group->mark_mutex);
663
664 fsnotify_put_mark(fsn_mark);
665 return 0;
666}
667
668static int fanotify_add_inode_mark(struct fsnotify_group *group,
669 struct inode *inode, __u32 mask,
670 unsigned int flags)
671{
672 struct fsnotify_mark *fsn_mark;
673 __u32 added;
674
675 pr_debug("%s: group=%p inode=%p\n", __func__, group, inode);
676
677 /*
678 * If some other task has this inode open for write we should not add
679 * an ignored mark, unless that ignored mark is supposed to survive
680 * modification changes anyway.
681 */
682 if ((flags & FAN_MARK_IGNORED_MASK) &&
683 !(flags & FAN_MARK_IGNORED_SURV_MODIFY) &&
684 (atomic_read(&inode->i_writecount) > 0))
685 return 0;
686
687 mutex_lock(&group->mark_mutex);
688 fsn_mark = fsnotify_find_mark(&inode->i_fsnotify_marks, group);
689 if (!fsn_mark) {
690 fsn_mark = fanotify_add_new_mark(group, inode, NULL);
691 if (IS_ERR(fsn_mark)) {
692 mutex_unlock(&group->mark_mutex);
693 return PTR_ERR(fsn_mark);
694 }
695 }
696 added = fanotify_mark_add_to_mask(fsn_mark, mask, flags);
697 if (added & ~inode->i_fsnotify_mask)
698 fsnotify_recalc_mask(inode->i_fsnotify_marks);
699 mutex_unlock(&group->mark_mutex);
700
701 fsnotify_put_mark(fsn_mark);
702 return 0;
703}
704
705/* fanotify syscalls */
706SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
707{
708 struct fsnotify_group *group;
709 int f_flags, fd;
710 struct user_struct *user;
711 struct fanotify_event_info *oevent;
712
713 pr_debug("%s: flags=%d event_f_flags=%d\n",
714 __func__, flags, event_f_flags);
715
716 if (!capable(CAP_SYS_ADMIN))
717 return -EPERM;
718
719#ifdef CONFIG_AUDITSYSCALL
720 if (flags & ~(FAN_ALL_INIT_FLAGS | FAN_ENABLE_AUDIT))
721#else
722 if (flags & ~FAN_ALL_INIT_FLAGS)
723#endif
724 return -EINVAL;
725
726 if (event_f_flags & ~FANOTIFY_INIT_ALL_EVENT_F_BITS)
727 return -EINVAL;
728
729 switch (event_f_flags & O_ACCMODE) {
730 case O_RDONLY:
731 case O_RDWR:
732 case O_WRONLY:
733 break;
734 default:
735 return -EINVAL;
736 }
737
738 user = get_current_user();
739 if (atomic_read(&user->fanotify_listeners) > FANOTIFY_DEFAULT_MAX_LISTENERS) {
740 free_uid(user);
741 return -EMFILE;
742 }
743
744 f_flags = O_RDWR | FMODE_NONOTIFY;
745 if (flags & FAN_CLOEXEC)
746 f_flags |= O_CLOEXEC;
747 if (flags & FAN_NONBLOCK)
748 f_flags |= O_NONBLOCK;
749
750 /* fsnotify_alloc_group takes a ref. Dropped in fanotify_release */
751 group = fsnotify_alloc_group(&fanotify_fsnotify_ops);
752 if (IS_ERR(group)) {
753 free_uid(user);
754 return PTR_ERR(group);
755 }
756
757 group->fanotify_data.user = user;
758 atomic_inc(&user->fanotify_listeners);
759
760 oevent = fanotify_alloc_event(group, NULL, FS_Q_OVERFLOW, NULL);
761 if (unlikely(!oevent)) {
762 fd = -ENOMEM;
763 goto out_destroy_group;
764 }
765 group->overflow_event = &oevent->fse;
766
767 if (force_o_largefile())
768 event_f_flags |= O_LARGEFILE;
769 group->fanotify_data.f_flags = event_f_flags;
770 init_waitqueue_head(&group->fanotify_data.access_waitq);
771 INIT_LIST_HEAD(&group->fanotify_data.access_list);
772 switch (flags & FAN_ALL_CLASS_BITS) {
773 case FAN_CLASS_NOTIF:
774 group->priority = FS_PRIO_0;
775 break;
776 case FAN_CLASS_CONTENT:
777 group->priority = FS_PRIO_1;
778 break;
779 case FAN_CLASS_PRE_CONTENT:
780 group->priority = FS_PRIO_2;
781 break;
782 default:
783 fd = -EINVAL;
784 goto out_destroy_group;
785 }
786
787 if (flags & FAN_UNLIMITED_QUEUE) {
788 fd = -EPERM;
789 if (!capable(CAP_SYS_ADMIN))
790 goto out_destroy_group;
791 group->max_events = UINT_MAX;
792 } else {
793 group->max_events = FANOTIFY_DEFAULT_MAX_EVENTS;
794 }
795
796 if (flags & FAN_UNLIMITED_MARKS) {
797 fd = -EPERM;
798 if (!capable(CAP_SYS_ADMIN))
799 goto out_destroy_group;
800 group->fanotify_data.max_marks = UINT_MAX;
801 } else {
802 group->fanotify_data.max_marks = FANOTIFY_DEFAULT_MAX_MARKS;
803 }
804
805 if (flags & FAN_ENABLE_AUDIT) {
806 fd = -EPERM;
807 if (!capable(CAP_AUDIT_WRITE))
808 goto out_destroy_group;
809 group->fanotify_data.audit = true;
810 }
811
812 fd = anon_inode_getfd("[fanotify]", &fanotify_fops, group, f_flags);
813 if (fd < 0)
814 goto out_destroy_group;
815
816 return fd;
817
818out_destroy_group:
819 fsnotify_destroy_group(group);
820 return fd;
821}
822
823static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
824 int dfd, const char __user *pathname)
825{
826 struct inode *inode = NULL;
827 struct vfsmount *mnt = NULL;
828 struct fsnotify_group *group;
829 struct fd f;
830 struct path path;
831 u32 valid_mask = FAN_ALL_EVENTS | FAN_EVENT_ON_CHILD;
832 int ret;
833
834 pr_debug("%s: fanotify_fd=%d flags=%x dfd=%d pathname=%p mask=%llx\n",
835 __func__, fanotify_fd, flags, dfd, pathname, mask);
836
837 /* we only use the lower 32 bits as of right now. */
838 if (mask & ((__u64)0xffffffff << 32))
839 return -EINVAL;
840
841 if (flags & ~FAN_ALL_MARK_FLAGS)
842 return -EINVAL;
843 switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) {
844 case FAN_MARK_ADD: /* fallthrough */
845 case FAN_MARK_REMOVE:
846 if (!mask)
847 return -EINVAL;
848 break;
849 case FAN_MARK_FLUSH:
850 if (flags & ~(FAN_MARK_MOUNT | FAN_MARK_FLUSH))
851 return -EINVAL;
852 break;
853 default:
854 return -EINVAL;
855 }
856
857 if (mask & FAN_ONDIR) {
858 flags |= FAN_MARK_ONDIR;
859 mask &= ~FAN_ONDIR;
860 }
861
862 if (IS_ENABLED(CONFIG_FANOTIFY_ACCESS_PERMISSIONS))
863 valid_mask |= FAN_ALL_PERM_EVENTS;
864
865 if (mask & ~valid_mask)
866 return -EINVAL;
867
868 f = fdget(fanotify_fd);
869 if (unlikely(!f.file))
870 return -EBADF;
871
872 /* verify that this is indeed an fanotify instance */
873 ret = -EINVAL;
874 if (unlikely(f.file->f_op != &fanotify_fops))
875 goto fput_and_out;
876 group = f.file->private_data;
877
878 /*
879 * group->priority == FS_PRIO_0 == FAN_CLASS_NOTIF. These are not
880 * allowed to set permissions events.
881 */
882 ret = -EINVAL;
883 if (mask & FAN_ALL_PERM_EVENTS &&
884 group->priority == FS_PRIO_0)
885 goto fput_and_out;
886
887 if (flags & FAN_MARK_FLUSH) {
888 ret = 0;
889 if (flags & FAN_MARK_MOUNT)
890 fsnotify_clear_vfsmount_marks_by_group(group);
891 else
892 fsnotify_clear_inode_marks_by_group(group);
893 goto fput_and_out;
894 }
895
896 ret = fanotify_find_path(dfd, pathname, &path, flags);
897 if (ret)
898 goto fput_and_out;
899
900 /* inode held in place by reference to path; group by fget on fd */
901 if (!(flags & FAN_MARK_MOUNT))
902 inode = path.dentry->d_inode;
903 else
904 mnt = path.mnt;
905
906 /* create/update an inode mark */
907 switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE)) {
908 case FAN_MARK_ADD:
909 if (flags & FAN_MARK_MOUNT)
910 ret = fanotify_add_vfsmount_mark(group, mnt, mask, flags);
911 else
912 ret = fanotify_add_inode_mark(group, inode, mask, flags);
913 break;
914 case FAN_MARK_REMOVE:
915 if (flags & FAN_MARK_MOUNT)
916 ret = fanotify_remove_vfsmount_mark(group, mnt, mask, flags);
917 else
918 ret = fanotify_remove_inode_mark(group, inode, mask, flags);
919 break;
920 default:
921 ret = -EINVAL;
922 }
923
924 path_put(&path);
925fput_and_out:
926 fdput(f);
927 return ret;
928}
929
930SYSCALL_DEFINE5(fanotify_mark, int, fanotify_fd, unsigned int, flags,
931 __u64, mask, int, dfd,
932 const char __user *, pathname)
933{
934 return do_fanotify_mark(fanotify_fd, flags, mask, dfd, pathname);
935}
936
937#ifdef CONFIG_COMPAT
938COMPAT_SYSCALL_DEFINE6(fanotify_mark,
939 int, fanotify_fd, unsigned int, flags,
940 __u32, mask0, __u32, mask1, int, dfd,
941 const char __user *, pathname)
942{
943 return do_fanotify_mark(fanotify_fd, flags,
944#ifdef __BIG_ENDIAN
945 ((__u64)mask0 << 32) | mask1,
946#else
947 ((__u64)mask1 << 32) | mask0,
948#endif
949 dfd, pathname);
950}
951#endif
952
953/*
954 * fanotify_user_setup - Our initialization function. Note that we cannot return
955 * error because we have compiled-in VFS hooks. So an (unlikely) failure here
956 * must result in panic().
957 */
958static int __init fanotify_user_setup(void)
959{
960 fanotify_mark_cache = KMEM_CACHE(fsnotify_mark, SLAB_PANIC);
961 fanotify_event_cachep = KMEM_CACHE(fanotify_event_info, SLAB_PANIC);
962 if (IS_ENABLED(CONFIG_FANOTIFY_ACCESS_PERMISSIONS)) {
963 fanotify_perm_event_cachep =
964 KMEM_CACHE(fanotify_perm_event_info, SLAB_PANIC);
965 }
966
967 return 0;
968}
969device_initcall(fanotify_user_setup);
1// SPDX-License-Identifier: GPL-2.0
2#include <linux/fanotify.h>
3#include <linux/fcntl.h>
4#include <linux/fdtable.h>
5#include <linux/file.h>
6#include <linux/fs.h>
7#include <linux/anon_inodes.h>
8#include <linux/fsnotify_backend.h>
9#include <linux/init.h>
10#include <linux/mount.h>
11#include <linux/namei.h>
12#include <linux/poll.h>
13#include <linux/security.h>
14#include <linux/syscalls.h>
15#include <linux/slab.h>
16#include <linux/types.h>
17#include <linux/uaccess.h>
18#include <linux/compat.h>
19#include <linux/sched/signal.h>
20#include <linux/memcontrol.h>
21#include <linux/statfs.h>
22#include <linux/exportfs.h>
23
24#include <asm/ioctls.h>
25
26#include "../../mount.h"
27#include "../fdinfo.h"
28#include "fanotify.h"
29
30#define FANOTIFY_DEFAULT_MAX_EVENTS 16384
31#define FANOTIFY_OLD_DEFAULT_MAX_MARKS 8192
32#define FANOTIFY_DEFAULT_MAX_GROUPS 128
33#define FANOTIFY_DEFAULT_FEE_POOL_SIZE 32
34
35/*
36 * Legacy fanotify marks limits (8192) is per group and we introduced a tunable
37 * limit of marks per user, similar to inotify. Effectively, the legacy limit
38 * of fanotify marks per user is <max marks per group> * <max groups per user>.
39 * This default limit (1M) also happens to match the increased limit of inotify
40 * max_user_watches since v5.10.
41 */
42#define FANOTIFY_DEFAULT_MAX_USER_MARKS \
43 (FANOTIFY_OLD_DEFAULT_MAX_MARKS * FANOTIFY_DEFAULT_MAX_GROUPS)
44
45/*
46 * Most of the memory cost of adding an inode mark is pinning the marked inode.
47 * The size of the filesystem inode struct is not uniform across filesystems,
48 * so double the size of a VFS inode is used as a conservative approximation.
49 */
50#define INODE_MARK_COST (2 * sizeof(struct inode))
51
52/* configurable via /proc/sys/fs/fanotify/ */
53static int fanotify_max_queued_events __read_mostly;
54
55#ifdef CONFIG_SYSCTL
56
57#include <linux/sysctl.h>
58
59static long ft_zero = 0;
60static long ft_int_max = INT_MAX;
61
62static struct ctl_table fanotify_table[] = {
63 {
64 .procname = "max_user_groups",
65 .data = &init_user_ns.ucount_max[UCOUNT_FANOTIFY_GROUPS],
66 .maxlen = sizeof(long),
67 .mode = 0644,
68 .proc_handler = proc_doulongvec_minmax,
69 .extra1 = &ft_zero,
70 .extra2 = &ft_int_max,
71 },
72 {
73 .procname = "max_user_marks",
74 .data = &init_user_ns.ucount_max[UCOUNT_FANOTIFY_MARKS],
75 .maxlen = sizeof(long),
76 .mode = 0644,
77 .proc_handler = proc_doulongvec_minmax,
78 .extra1 = &ft_zero,
79 .extra2 = &ft_int_max,
80 },
81 {
82 .procname = "max_queued_events",
83 .data = &fanotify_max_queued_events,
84 .maxlen = sizeof(int),
85 .mode = 0644,
86 .proc_handler = proc_dointvec_minmax,
87 .extra1 = SYSCTL_ZERO
88 },
89 { }
90};
91
92static void __init fanotify_sysctls_init(void)
93{
94 register_sysctl("fs/fanotify", fanotify_table);
95}
96#else
97#define fanotify_sysctls_init() do { } while (0)
98#endif /* CONFIG_SYSCTL */
99
100/*
101 * All flags that may be specified in parameter event_f_flags of fanotify_init.
102 *
103 * Internal and external open flags are stored together in field f_flags of
104 * struct file. Only external open flags shall be allowed in event_f_flags.
105 * Internal flags like FMODE_NONOTIFY, FMODE_EXEC, FMODE_NOCMTIME shall be
106 * excluded.
107 */
108#define FANOTIFY_INIT_ALL_EVENT_F_BITS ( \
109 O_ACCMODE | O_APPEND | O_NONBLOCK | \
110 __O_SYNC | O_DSYNC | O_CLOEXEC | \
111 O_LARGEFILE | O_NOATIME )
112
113extern const struct fsnotify_ops fanotify_fsnotify_ops;
114
115struct kmem_cache *fanotify_mark_cache __read_mostly;
116struct kmem_cache *fanotify_fid_event_cachep __read_mostly;
117struct kmem_cache *fanotify_path_event_cachep __read_mostly;
118struct kmem_cache *fanotify_perm_event_cachep __read_mostly;
119
120#define FANOTIFY_EVENT_ALIGN 4
121#define FANOTIFY_FID_INFO_HDR_LEN \
122 (sizeof(struct fanotify_event_info_fid) + sizeof(struct file_handle))
123#define FANOTIFY_PIDFD_INFO_HDR_LEN \
124 sizeof(struct fanotify_event_info_pidfd)
125#define FANOTIFY_ERROR_INFO_LEN \
126 (sizeof(struct fanotify_event_info_error))
127
128static int fanotify_fid_info_len(int fh_len, int name_len)
129{
130 int info_len = fh_len;
131
132 if (name_len)
133 info_len += name_len + 1;
134
135 return roundup(FANOTIFY_FID_INFO_HDR_LEN + info_len,
136 FANOTIFY_EVENT_ALIGN);
137}
138
139/* FAN_RENAME may have one or two dir+name info records */
140static int fanotify_dir_name_info_len(struct fanotify_event *event)
141{
142 struct fanotify_info *info = fanotify_event_info(event);
143 int dir_fh_len = fanotify_event_dir_fh_len(event);
144 int dir2_fh_len = fanotify_event_dir2_fh_len(event);
145 int info_len = 0;
146
147 if (dir_fh_len)
148 info_len += fanotify_fid_info_len(dir_fh_len,
149 info->name_len);
150 if (dir2_fh_len)
151 info_len += fanotify_fid_info_len(dir2_fh_len,
152 info->name2_len);
153
154 return info_len;
155}
156
157static size_t fanotify_event_len(unsigned int info_mode,
158 struct fanotify_event *event)
159{
160 size_t event_len = FAN_EVENT_METADATA_LEN;
161 int fh_len;
162 int dot_len = 0;
163
164 if (!info_mode)
165 return event_len;
166
167 if (fanotify_is_error_event(event->mask))
168 event_len += FANOTIFY_ERROR_INFO_LEN;
169
170 if (fanotify_event_has_any_dir_fh(event)) {
171 event_len += fanotify_dir_name_info_len(event);
172 } else if ((info_mode & FAN_REPORT_NAME) &&
173 (event->mask & FAN_ONDIR)) {
174 /*
175 * With group flag FAN_REPORT_NAME, if name was not recorded in
176 * event on a directory, we will report the name ".".
177 */
178 dot_len = 1;
179 }
180
181 if (info_mode & FAN_REPORT_PIDFD)
182 event_len += FANOTIFY_PIDFD_INFO_HDR_LEN;
183
184 if (fanotify_event_has_object_fh(event)) {
185 fh_len = fanotify_event_object_fh_len(event);
186 event_len += fanotify_fid_info_len(fh_len, dot_len);
187 }
188
189 return event_len;
190}
191
192/*
193 * Remove an hashed event from merge hash table.
194 */
195static void fanotify_unhash_event(struct fsnotify_group *group,
196 struct fanotify_event *event)
197{
198 assert_spin_locked(&group->notification_lock);
199
200 pr_debug("%s: group=%p event=%p bucket=%u\n", __func__,
201 group, event, fanotify_event_hash_bucket(group, event));
202
203 if (WARN_ON_ONCE(hlist_unhashed(&event->merge_list)))
204 return;
205
206 hlist_del_init(&event->merge_list);
207}
208
209/*
210 * Get an fanotify notification event if one exists and is small
211 * enough to fit in "count". Return an error pointer if the count
212 * is not large enough. When permission event is dequeued, its state is
213 * updated accordingly.
214 */
215static struct fanotify_event *get_one_event(struct fsnotify_group *group,
216 size_t count)
217{
218 size_t event_size;
219 struct fanotify_event *event = NULL;
220 struct fsnotify_event *fsn_event;
221 unsigned int info_mode = FAN_GROUP_FLAG(group, FANOTIFY_INFO_MODES);
222
223 pr_debug("%s: group=%p count=%zd\n", __func__, group, count);
224
225 spin_lock(&group->notification_lock);
226 fsn_event = fsnotify_peek_first_event(group);
227 if (!fsn_event)
228 goto out;
229
230 event = FANOTIFY_E(fsn_event);
231 event_size = fanotify_event_len(info_mode, event);
232
233 if (event_size > count) {
234 event = ERR_PTR(-EINVAL);
235 goto out;
236 }
237
238 /*
239 * Held the notification_lock the whole time, so this is the
240 * same event we peeked above.
241 */
242 fsnotify_remove_first_event(group);
243 if (fanotify_is_perm_event(event->mask))
244 FANOTIFY_PERM(event)->state = FAN_EVENT_REPORTED;
245 if (fanotify_is_hashed_event(event->mask))
246 fanotify_unhash_event(group, event);
247out:
248 spin_unlock(&group->notification_lock);
249 return event;
250}
251
252static int create_fd(struct fsnotify_group *group, const struct path *path,
253 struct file **file)
254{
255 int client_fd;
256 struct file *new_file;
257
258 client_fd = get_unused_fd_flags(group->fanotify_data.f_flags);
259 if (client_fd < 0)
260 return client_fd;
261
262 /*
263 * we need a new file handle for the userspace program so it can read even if it was
264 * originally opened O_WRONLY.
265 */
266 new_file = dentry_open(path,
267 group->fanotify_data.f_flags | __FMODE_NONOTIFY,
268 current_cred());
269 if (IS_ERR(new_file)) {
270 /*
271 * we still send an event even if we can't open the file. this
272 * can happen when say tasks are gone and we try to open their
273 * /proc files or we try to open a WRONLY file like in sysfs
274 * we just send the errno to userspace since there isn't much
275 * else we can do.
276 */
277 put_unused_fd(client_fd);
278 client_fd = PTR_ERR(new_file);
279 } else {
280 *file = new_file;
281 }
282
283 return client_fd;
284}
285
286/*
287 * Finish processing of permission event by setting it to ANSWERED state and
288 * drop group->notification_lock.
289 */
290static void finish_permission_event(struct fsnotify_group *group,
291 struct fanotify_perm_event *event,
292 unsigned int response)
293 __releases(&group->notification_lock)
294{
295 bool destroy = false;
296
297 assert_spin_locked(&group->notification_lock);
298 event->response = response;
299 if (event->state == FAN_EVENT_CANCELED)
300 destroy = true;
301 else
302 event->state = FAN_EVENT_ANSWERED;
303 spin_unlock(&group->notification_lock);
304 if (destroy)
305 fsnotify_destroy_event(group, &event->fae.fse);
306}
307
308static int process_access_response(struct fsnotify_group *group,
309 struct fanotify_response *response_struct)
310{
311 struct fanotify_perm_event *event;
312 int fd = response_struct->fd;
313 int response = response_struct->response;
314
315 pr_debug("%s: group=%p fd=%d response=%d\n", __func__, group,
316 fd, response);
317 /*
318 * make sure the response is valid, if invalid we do nothing and either
319 * userspace can send a valid response or we will clean it up after the
320 * timeout
321 */
322 switch (response & ~FAN_AUDIT) {
323 case FAN_ALLOW:
324 case FAN_DENY:
325 break;
326 default:
327 return -EINVAL;
328 }
329
330 if (fd < 0)
331 return -EINVAL;
332
333 if ((response & FAN_AUDIT) && !FAN_GROUP_FLAG(group, FAN_ENABLE_AUDIT))
334 return -EINVAL;
335
336 spin_lock(&group->notification_lock);
337 list_for_each_entry(event, &group->fanotify_data.access_list,
338 fae.fse.list) {
339 if (event->fd != fd)
340 continue;
341
342 list_del_init(&event->fae.fse.list);
343 finish_permission_event(group, event, response);
344 wake_up(&group->fanotify_data.access_waitq);
345 return 0;
346 }
347 spin_unlock(&group->notification_lock);
348
349 return -ENOENT;
350}
351
352static size_t copy_error_info_to_user(struct fanotify_event *event,
353 char __user *buf, int count)
354{
355 struct fanotify_event_info_error info = { };
356 struct fanotify_error_event *fee = FANOTIFY_EE(event);
357
358 info.hdr.info_type = FAN_EVENT_INFO_TYPE_ERROR;
359 info.hdr.len = FANOTIFY_ERROR_INFO_LEN;
360
361 if (WARN_ON(count < info.hdr.len))
362 return -EFAULT;
363
364 info.error = fee->error;
365 info.error_count = fee->err_count;
366
367 if (copy_to_user(buf, &info, sizeof(info)))
368 return -EFAULT;
369
370 return info.hdr.len;
371}
372
373static int copy_fid_info_to_user(__kernel_fsid_t *fsid, struct fanotify_fh *fh,
374 int info_type, const char *name,
375 size_t name_len,
376 char __user *buf, size_t count)
377{
378 struct fanotify_event_info_fid info = { };
379 struct file_handle handle = { };
380 unsigned char bounce[FANOTIFY_INLINE_FH_LEN], *fh_buf;
381 size_t fh_len = fh ? fh->len : 0;
382 size_t info_len = fanotify_fid_info_len(fh_len, name_len);
383 size_t len = info_len;
384
385 pr_debug("%s: fh_len=%zu name_len=%zu, info_len=%zu, count=%zu\n",
386 __func__, fh_len, name_len, info_len, count);
387
388 if (WARN_ON_ONCE(len < sizeof(info) || len > count))
389 return -EFAULT;
390
391 /*
392 * Copy event info fid header followed by variable sized file handle
393 * and optionally followed by variable sized filename.
394 */
395 switch (info_type) {
396 case FAN_EVENT_INFO_TYPE_FID:
397 case FAN_EVENT_INFO_TYPE_DFID:
398 if (WARN_ON_ONCE(name_len))
399 return -EFAULT;
400 break;
401 case FAN_EVENT_INFO_TYPE_DFID_NAME:
402 case FAN_EVENT_INFO_TYPE_OLD_DFID_NAME:
403 case FAN_EVENT_INFO_TYPE_NEW_DFID_NAME:
404 if (WARN_ON_ONCE(!name || !name_len))
405 return -EFAULT;
406 break;
407 default:
408 return -EFAULT;
409 }
410
411 info.hdr.info_type = info_type;
412 info.hdr.len = len;
413 info.fsid = *fsid;
414 if (copy_to_user(buf, &info, sizeof(info)))
415 return -EFAULT;
416
417 buf += sizeof(info);
418 len -= sizeof(info);
419 if (WARN_ON_ONCE(len < sizeof(handle)))
420 return -EFAULT;
421
422 handle.handle_type = fh->type;
423 handle.handle_bytes = fh_len;
424
425 /* Mangle handle_type for bad file_handle */
426 if (!fh_len)
427 handle.handle_type = FILEID_INVALID;
428
429 if (copy_to_user(buf, &handle, sizeof(handle)))
430 return -EFAULT;
431
432 buf += sizeof(handle);
433 len -= sizeof(handle);
434 if (WARN_ON_ONCE(len < fh_len))
435 return -EFAULT;
436
437 /*
438 * For an inline fh and inline file name, copy through stack to exclude
439 * the copy from usercopy hardening protections.
440 */
441 fh_buf = fanotify_fh_buf(fh);
442 if (fh_len <= FANOTIFY_INLINE_FH_LEN) {
443 memcpy(bounce, fh_buf, fh_len);
444 fh_buf = bounce;
445 }
446 if (copy_to_user(buf, fh_buf, fh_len))
447 return -EFAULT;
448
449 buf += fh_len;
450 len -= fh_len;
451
452 if (name_len) {
453 /* Copy the filename with terminating null */
454 name_len++;
455 if (WARN_ON_ONCE(len < name_len))
456 return -EFAULT;
457
458 if (copy_to_user(buf, name, name_len))
459 return -EFAULT;
460
461 buf += name_len;
462 len -= name_len;
463 }
464
465 /* Pad with 0's */
466 WARN_ON_ONCE(len < 0 || len >= FANOTIFY_EVENT_ALIGN);
467 if (len > 0 && clear_user(buf, len))
468 return -EFAULT;
469
470 return info_len;
471}
472
473static int copy_pidfd_info_to_user(int pidfd,
474 char __user *buf,
475 size_t count)
476{
477 struct fanotify_event_info_pidfd info = { };
478 size_t info_len = FANOTIFY_PIDFD_INFO_HDR_LEN;
479
480 if (WARN_ON_ONCE(info_len > count))
481 return -EFAULT;
482
483 info.hdr.info_type = FAN_EVENT_INFO_TYPE_PIDFD;
484 info.hdr.len = info_len;
485 info.pidfd = pidfd;
486
487 if (copy_to_user(buf, &info, info_len))
488 return -EFAULT;
489
490 return info_len;
491}
492
493static int copy_info_records_to_user(struct fanotify_event *event,
494 struct fanotify_info *info,
495 unsigned int info_mode, int pidfd,
496 char __user *buf, size_t count)
497{
498 int ret, total_bytes = 0, info_type = 0;
499 unsigned int fid_mode = info_mode & FANOTIFY_FID_BITS;
500 unsigned int pidfd_mode = info_mode & FAN_REPORT_PIDFD;
501
502 /*
503 * Event info records order is as follows:
504 * 1. dir fid + name
505 * 2. (optional) new dir fid + new name
506 * 3. (optional) child fid
507 */
508 if (fanotify_event_has_dir_fh(event)) {
509 info_type = info->name_len ? FAN_EVENT_INFO_TYPE_DFID_NAME :
510 FAN_EVENT_INFO_TYPE_DFID;
511
512 /* FAN_RENAME uses special info types */
513 if (event->mask & FAN_RENAME)
514 info_type = FAN_EVENT_INFO_TYPE_OLD_DFID_NAME;
515
516 ret = copy_fid_info_to_user(fanotify_event_fsid(event),
517 fanotify_info_dir_fh(info),
518 info_type,
519 fanotify_info_name(info),
520 info->name_len, buf, count);
521 if (ret < 0)
522 return ret;
523
524 buf += ret;
525 count -= ret;
526 total_bytes += ret;
527 }
528
529 /* New dir fid+name may be reported in addition to old dir fid+name */
530 if (fanotify_event_has_dir2_fh(event)) {
531 info_type = FAN_EVENT_INFO_TYPE_NEW_DFID_NAME;
532 ret = copy_fid_info_to_user(fanotify_event_fsid(event),
533 fanotify_info_dir2_fh(info),
534 info_type,
535 fanotify_info_name2(info),
536 info->name2_len, buf, count);
537 if (ret < 0)
538 return ret;
539
540 buf += ret;
541 count -= ret;
542 total_bytes += ret;
543 }
544
545 if (fanotify_event_has_object_fh(event)) {
546 const char *dot = NULL;
547 int dot_len = 0;
548
549 if (fid_mode == FAN_REPORT_FID || info_type) {
550 /*
551 * With only group flag FAN_REPORT_FID only type FID is
552 * reported. Second info record type is always FID.
553 */
554 info_type = FAN_EVENT_INFO_TYPE_FID;
555 } else if ((fid_mode & FAN_REPORT_NAME) &&
556 (event->mask & FAN_ONDIR)) {
557 /*
558 * With group flag FAN_REPORT_NAME, if name was not
559 * recorded in an event on a directory, report the name
560 * "." with info type DFID_NAME.
561 */
562 info_type = FAN_EVENT_INFO_TYPE_DFID_NAME;
563 dot = ".";
564 dot_len = 1;
565 } else if ((event->mask & ALL_FSNOTIFY_DIRENT_EVENTS) ||
566 (event->mask & FAN_ONDIR)) {
567 /*
568 * With group flag FAN_REPORT_DIR_FID, a single info
569 * record has type DFID for directory entry modification
570 * event and for event on a directory.
571 */
572 info_type = FAN_EVENT_INFO_TYPE_DFID;
573 } else {
574 /*
575 * With group flags FAN_REPORT_DIR_FID|FAN_REPORT_FID,
576 * a single info record has type FID for event on a
577 * non-directory, when there is no directory to report.
578 * For example, on FAN_DELETE_SELF event.
579 */
580 info_type = FAN_EVENT_INFO_TYPE_FID;
581 }
582
583 ret = copy_fid_info_to_user(fanotify_event_fsid(event),
584 fanotify_event_object_fh(event),
585 info_type, dot, dot_len,
586 buf, count);
587 if (ret < 0)
588 return ret;
589
590 buf += ret;
591 count -= ret;
592 total_bytes += ret;
593 }
594
595 if (pidfd_mode) {
596 ret = copy_pidfd_info_to_user(pidfd, buf, count);
597 if (ret < 0)
598 return ret;
599
600 buf += ret;
601 count -= ret;
602 total_bytes += ret;
603 }
604
605 if (fanotify_is_error_event(event->mask)) {
606 ret = copy_error_info_to_user(event, buf, count);
607 if (ret < 0)
608 return ret;
609 buf += ret;
610 count -= ret;
611 total_bytes += ret;
612 }
613
614 return total_bytes;
615}
616
617static ssize_t copy_event_to_user(struct fsnotify_group *group,
618 struct fanotify_event *event,
619 char __user *buf, size_t count)
620{
621 struct fanotify_event_metadata metadata;
622 const struct path *path = fanotify_event_path(event);
623 struct fanotify_info *info = fanotify_event_info(event);
624 unsigned int info_mode = FAN_GROUP_FLAG(group, FANOTIFY_INFO_MODES);
625 unsigned int pidfd_mode = info_mode & FAN_REPORT_PIDFD;
626 struct file *f = NULL;
627 int ret, pidfd = FAN_NOPIDFD, fd = FAN_NOFD;
628
629 pr_debug("%s: group=%p event=%p\n", __func__, group, event);
630
631 metadata.event_len = fanotify_event_len(info_mode, event);
632 metadata.metadata_len = FAN_EVENT_METADATA_LEN;
633 metadata.vers = FANOTIFY_METADATA_VERSION;
634 metadata.reserved = 0;
635 metadata.mask = event->mask & FANOTIFY_OUTGOING_EVENTS;
636 metadata.pid = pid_vnr(event->pid);
637 /*
638 * For an unprivileged listener, event->pid can be used to identify the
639 * events generated by the listener process itself, without disclosing
640 * the pids of other processes.
641 */
642 if (FAN_GROUP_FLAG(group, FANOTIFY_UNPRIV) &&
643 task_tgid(current) != event->pid)
644 metadata.pid = 0;
645
646 /*
647 * For now, fid mode is required for an unprivileged listener and
648 * fid mode does not report fd in events. Keep this check anyway
649 * for safety in case fid mode requirement is relaxed in the future
650 * to allow unprivileged listener to get events with no fd and no fid.
651 */
652 if (!FAN_GROUP_FLAG(group, FANOTIFY_UNPRIV) &&
653 path && path->mnt && path->dentry) {
654 fd = create_fd(group, path, &f);
655 if (fd < 0)
656 return fd;
657 }
658 metadata.fd = fd;
659
660 if (pidfd_mode) {
661 /*
662 * Complain if the FAN_REPORT_PIDFD and FAN_REPORT_TID mutual
663 * exclusion is ever lifted. At the time of incoporating pidfd
664 * support within fanotify, the pidfd API only supported the
665 * creation of pidfds for thread-group leaders.
666 */
667 WARN_ON_ONCE(FAN_GROUP_FLAG(group, FAN_REPORT_TID));
668
669 /*
670 * The PIDTYPE_TGID check for an event->pid is performed
671 * preemptively in an attempt to catch out cases where the event
672 * listener reads events after the event generating process has
673 * already terminated. Report FAN_NOPIDFD to the event listener
674 * in those cases, with all other pidfd creation errors being
675 * reported as FAN_EPIDFD.
676 */
677 if (metadata.pid == 0 ||
678 !pid_has_task(event->pid, PIDTYPE_TGID)) {
679 pidfd = FAN_NOPIDFD;
680 } else {
681 pidfd = pidfd_create(event->pid, 0);
682 if (pidfd < 0)
683 pidfd = FAN_EPIDFD;
684 }
685 }
686
687 ret = -EFAULT;
688 /*
689 * Sanity check copy size in case get_one_event() and
690 * event_len sizes ever get out of sync.
691 */
692 if (WARN_ON_ONCE(metadata.event_len > count))
693 goto out_close_fd;
694
695 if (copy_to_user(buf, &metadata, FAN_EVENT_METADATA_LEN))
696 goto out_close_fd;
697
698 buf += FAN_EVENT_METADATA_LEN;
699 count -= FAN_EVENT_METADATA_LEN;
700
701 if (fanotify_is_perm_event(event->mask))
702 FANOTIFY_PERM(event)->fd = fd;
703
704 if (info_mode) {
705 ret = copy_info_records_to_user(event, info, info_mode, pidfd,
706 buf, count);
707 if (ret < 0)
708 goto out_close_fd;
709 }
710
711 if (f)
712 fd_install(fd, f);
713
714 return metadata.event_len;
715
716out_close_fd:
717 if (fd != FAN_NOFD) {
718 put_unused_fd(fd);
719 fput(f);
720 }
721
722 if (pidfd >= 0)
723 close_fd(pidfd);
724
725 return ret;
726}
727
728/* intofiy userspace file descriptor functions */
729static __poll_t fanotify_poll(struct file *file, poll_table *wait)
730{
731 struct fsnotify_group *group = file->private_data;
732 __poll_t ret = 0;
733
734 poll_wait(file, &group->notification_waitq, wait);
735 spin_lock(&group->notification_lock);
736 if (!fsnotify_notify_queue_is_empty(group))
737 ret = EPOLLIN | EPOLLRDNORM;
738 spin_unlock(&group->notification_lock);
739
740 return ret;
741}
742
743static ssize_t fanotify_read(struct file *file, char __user *buf,
744 size_t count, loff_t *pos)
745{
746 struct fsnotify_group *group;
747 struct fanotify_event *event;
748 char __user *start;
749 int ret;
750 DEFINE_WAIT_FUNC(wait, woken_wake_function);
751
752 start = buf;
753 group = file->private_data;
754
755 pr_debug("%s: group=%p\n", __func__, group);
756
757 add_wait_queue(&group->notification_waitq, &wait);
758 while (1) {
759 /*
760 * User can supply arbitrarily large buffer. Avoid softlockups
761 * in case there are lots of available events.
762 */
763 cond_resched();
764 event = get_one_event(group, count);
765 if (IS_ERR(event)) {
766 ret = PTR_ERR(event);
767 break;
768 }
769
770 if (!event) {
771 ret = -EAGAIN;
772 if (file->f_flags & O_NONBLOCK)
773 break;
774
775 ret = -ERESTARTSYS;
776 if (signal_pending(current))
777 break;
778
779 if (start != buf)
780 break;
781
782 wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
783 continue;
784 }
785
786 ret = copy_event_to_user(group, event, buf, count);
787 if (unlikely(ret == -EOPENSTALE)) {
788 /*
789 * We cannot report events with stale fd so drop it.
790 * Setting ret to 0 will continue the event loop and
791 * do the right thing if there are no more events to
792 * read (i.e. return bytes read, -EAGAIN or wait).
793 */
794 ret = 0;
795 }
796
797 /*
798 * Permission events get queued to wait for response. Other
799 * events can be destroyed now.
800 */
801 if (!fanotify_is_perm_event(event->mask)) {
802 fsnotify_destroy_event(group, &event->fse);
803 } else {
804 if (ret <= 0) {
805 spin_lock(&group->notification_lock);
806 finish_permission_event(group,
807 FANOTIFY_PERM(event), FAN_DENY);
808 wake_up(&group->fanotify_data.access_waitq);
809 } else {
810 spin_lock(&group->notification_lock);
811 list_add_tail(&event->fse.list,
812 &group->fanotify_data.access_list);
813 spin_unlock(&group->notification_lock);
814 }
815 }
816 if (ret < 0)
817 break;
818 buf += ret;
819 count -= ret;
820 }
821 remove_wait_queue(&group->notification_waitq, &wait);
822
823 if (start != buf && ret != -EFAULT)
824 ret = buf - start;
825 return ret;
826}
827
828static ssize_t fanotify_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)
829{
830 struct fanotify_response response = { .fd = -1, .response = -1 };
831 struct fsnotify_group *group;
832 int ret;
833
834 if (!IS_ENABLED(CONFIG_FANOTIFY_ACCESS_PERMISSIONS))
835 return -EINVAL;
836
837 group = file->private_data;
838
839 if (count < sizeof(response))
840 return -EINVAL;
841
842 count = sizeof(response);
843
844 pr_debug("%s: group=%p count=%zu\n", __func__, group, count);
845
846 if (copy_from_user(&response, buf, count))
847 return -EFAULT;
848
849 ret = process_access_response(group, &response);
850 if (ret < 0)
851 count = ret;
852
853 return count;
854}
855
856static int fanotify_release(struct inode *ignored, struct file *file)
857{
858 struct fsnotify_group *group = file->private_data;
859 struct fsnotify_event *fsn_event;
860
861 /*
862 * Stop new events from arriving in the notification queue. since
863 * userspace cannot use fanotify fd anymore, no event can enter or
864 * leave access_list by now either.
865 */
866 fsnotify_group_stop_queueing(group);
867
868 /*
869 * Process all permission events on access_list and notification queue
870 * and simulate reply from userspace.
871 */
872 spin_lock(&group->notification_lock);
873 while (!list_empty(&group->fanotify_data.access_list)) {
874 struct fanotify_perm_event *event;
875
876 event = list_first_entry(&group->fanotify_data.access_list,
877 struct fanotify_perm_event, fae.fse.list);
878 list_del_init(&event->fae.fse.list);
879 finish_permission_event(group, event, FAN_ALLOW);
880 spin_lock(&group->notification_lock);
881 }
882
883 /*
884 * Destroy all non-permission events. For permission events just
885 * dequeue them and set the response. They will be freed once the
886 * response is consumed and fanotify_get_response() returns.
887 */
888 while ((fsn_event = fsnotify_remove_first_event(group))) {
889 struct fanotify_event *event = FANOTIFY_E(fsn_event);
890
891 if (!(event->mask & FANOTIFY_PERM_EVENTS)) {
892 spin_unlock(&group->notification_lock);
893 fsnotify_destroy_event(group, fsn_event);
894 } else {
895 finish_permission_event(group, FANOTIFY_PERM(event),
896 FAN_ALLOW);
897 }
898 spin_lock(&group->notification_lock);
899 }
900 spin_unlock(&group->notification_lock);
901
902 /* Response for all permission events it set, wakeup waiters */
903 wake_up(&group->fanotify_data.access_waitq);
904
905 /* matches the fanotify_init->fsnotify_alloc_group */
906 fsnotify_destroy_group(group);
907
908 return 0;
909}
910
911static long fanotify_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
912{
913 struct fsnotify_group *group;
914 struct fsnotify_event *fsn_event;
915 void __user *p;
916 int ret = -ENOTTY;
917 size_t send_len = 0;
918
919 group = file->private_data;
920
921 p = (void __user *) arg;
922
923 switch (cmd) {
924 case FIONREAD:
925 spin_lock(&group->notification_lock);
926 list_for_each_entry(fsn_event, &group->notification_list, list)
927 send_len += FAN_EVENT_METADATA_LEN;
928 spin_unlock(&group->notification_lock);
929 ret = put_user(send_len, (int __user *) p);
930 break;
931 }
932
933 return ret;
934}
935
936static const struct file_operations fanotify_fops = {
937 .show_fdinfo = fanotify_show_fdinfo,
938 .poll = fanotify_poll,
939 .read = fanotify_read,
940 .write = fanotify_write,
941 .fasync = NULL,
942 .release = fanotify_release,
943 .unlocked_ioctl = fanotify_ioctl,
944 .compat_ioctl = compat_ptr_ioctl,
945 .llseek = noop_llseek,
946};
947
948static int fanotify_find_path(int dfd, const char __user *filename,
949 struct path *path, unsigned int flags, __u64 mask,
950 unsigned int obj_type)
951{
952 int ret;
953
954 pr_debug("%s: dfd=%d filename=%p flags=%x\n", __func__,
955 dfd, filename, flags);
956
957 if (filename == NULL) {
958 struct fd f = fdget(dfd);
959
960 ret = -EBADF;
961 if (!f.file)
962 goto out;
963
964 ret = -ENOTDIR;
965 if ((flags & FAN_MARK_ONLYDIR) &&
966 !(S_ISDIR(file_inode(f.file)->i_mode))) {
967 fdput(f);
968 goto out;
969 }
970
971 *path = f.file->f_path;
972 path_get(path);
973 fdput(f);
974 } else {
975 unsigned int lookup_flags = 0;
976
977 if (!(flags & FAN_MARK_DONT_FOLLOW))
978 lookup_flags |= LOOKUP_FOLLOW;
979 if (flags & FAN_MARK_ONLYDIR)
980 lookup_flags |= LOOKUP_DIRECTORY;
981
982 ret = user_path_at(dfd, filename, lookup_flags, path);
983 if (ret)
984 goto out;
985 }
986
987 /* you can only watch an inode if you have read permissions on it */
988 ret = path_permission(path, MAY_READ);
989 if (ret) {
990 path_put(path);
991 goto out;
992 }
993
994 ret = security_path_notify(path, mask, obj_type);
995 if (ret)
996 path_put(path);
997
998out:
999 return ret;
1000}
1001
1002static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark,
1003 __u32 mask, unsigned int flags,
1004 __u32 umask, int *destroy)
1005{
1006 __u32 oldmask, newmask;
1007
1008 /* umask bits cannot be removed by user */
1009 mask &= ~umask;
1010 spin_lock(&fsn_mark->lock);
1011 oldmask = fsnotify_calc_mask(fsn_mark);
1012 if (!(flags & FANOTIFY_MARK_IGNORE_BITS)) {
1013 fsn_mark->mask &= ~mask;
1014 } else {
1015 fsn_mark->ignore_mask &= ~mask;
1016 }
1017 newmask = fsnotify_calc_mask(fsn_mark);
1018 /*
1019 * We need to keep the mark around even if remaining mask cannot
1020 * result in any events (e.g. mask == FAN_ONDIR) to support incremenal
1021 * changes to the mask.
1022 * Destroy mark when only umask bits remain.
1023 */
1024 *destroy = !((fsn_mark->mask | fsn_mark->ignore_mask) & ~umask);
1025 spin_unlock(&fsn_mark->lock);
1026
1027 return oldmask & ~newmask;
1028}
1029
1030static int fanotify_remove_mark(struct fsnotify_group *group,
1031 fsnotify_connp_t *connp, __u32 mask,
1032 unsigned int flags, __u32 umask)
1033{
1034 struct fsnotify_mark *fsn_mark = NULL;
1035 __u32 removed;
1036 int destroy_mark;
1037
1038 fsnotify_group_lock(group);
1039 fsn_mark = fsnotify_find_mark(connp, group);
1040 if (!fsn_mark) {
1041 fsnotify_group_unlock(group);
1042 return -ENOENT;
1043 }
1044
1045 removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags,
1046 umask, &destroy_mark);
1047 if (removed & fsnotify_conn_mask(fsn_mark->connector))
1048 fsnotify_recalc_mask(fsn_mark->connector);
1049 if (destroy_mark)
1050 fsnotify_detach_mark(fsn_mark);
1051 fsnotify_group_unlock(group);
1052 if (destroy_mark)
1053 fsnotify_free_mark(fsn_mark);
1054
1055 /* matches the fsnotify_find_mark() */
1056 fsnotify_put_mark(fsn_mark);
1057 return 0;
1058}
1059
1060static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group,
1061 struct vfsmount *mnt, __u32 mask,
1062 unsigned int flags, __u32 umask)
1063{
1064 return fanotify_remove_mark(group, &real_mount(mnt)->mnt_fsnotify_marks,
1065 mask, flags, umask);
1066}
1067
1068static int fanotify_remove_sb_mark(struct fsnotify_group *group,
1069 struct super_block *sb, __u32 mask,
1070 unsigned int flags, __u32 umask)
1071{
1072 return fanotify_remove_mark(group, &sb->s_fsnotify_marks, mask,
1073 flags, umask);
1074}
1075
1076static int fanotify_remove_inode_mark(struct fsnotify_group *group,
1077 struct inode *inode, __u32 mask,
1078 unsigned int flags, __u32 umask)
1079{
1080 return fanotify_remove_mark(group, &inode->i_fsnotify_marks, mask,
1081 flags, umask);
1082}
1083
1084static bool fanotify_mark_update_flags(struct fsnotify_mark *fsn_mark,
1085 unsigned int fan_flags)
1086{
1087 bool want_iref = !(fan_flags & FAN_MARK_EVICTABLE);
1088 unsigned int ignore = fan_flags & FANOTIFY_MARK_IGNORE_BITS;
1089 bool recalc = false;
1090
1091 /*
1092 * When using FAN_MARK_IGNORE for the first time, mark starts using
1093 * independent event flags in ignore mask. After that, trying to
1094 * update the ignore mask with the old FAN_MARK_IGNORED_MASK API
1095 * will result in EEXIST error.
1096 */
1097 if (ignore == FAN_MARK_IGNORE)
1098 fsn_mark->flags |= FSNOTIFY_MARK_FLAG_HAS_IGNORE_FLAGS;
1099
1100 /*
1101 * Setting FAN_MARK_IGNORED_SURV_MODIFY for the first time may lead to
1102 * the removal of the FS_MODIFY bit in calculated mask if it was set
1103 * because of an ignore mask that is now going to survive FS_MODIFY.
1104 */
1105 if (ignore && (fan_flags & FAN_MARK_IGNORED_SURV_MODIFY) &&
1106 !(fsn_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY)) {
1107 fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY;
1108 if (!(fsn_mark->mask & FS_MODIFY))
1109 recalc = true;
1110 }
1111
1112 if (fsn_mark->connector->type != FSNOTIFY_OBJ_TYPE_INODE ||
1113 want_iref == !(fsn_mark->flags & FSNOTIFY_MARK_FLAG_NO_IREF))
1114 return recalc;
1115
1116 /*
1117 * NO_IREF may be removed from a mark, but not added.
1118 * When removed, fsnotify_recalc_mask() will take the inode ref.
1119 */
1120 WARN_ON_ONCE(!want_iref);
1121 fsn_mark->flags &= ~FSNOTIFY_MARK_FLAG_NO_IREF;
1122
1123 return true;
1124}
1125
1126static bool fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark,
1127 __u32 mask, unsigned int fan_flags)
1128{
1129 bool recalc;
1130
1131 spin_lock(&fsn_mark->lock);
1132 if (!(fan_flags & FANOTIFY_MARK_IGNORE_BITS))
1133 fsn_mark->mask |= mask;
1134 else
1135 fsn_mark->ignore_mask |= mask;
1136
1137 recalc = fsnotify_calc_mask(fsn_mark) &
1138 ~fsnotify_conn_mask(fsn_mark->connector);
1139
1140 recalc |= fanotify_mark_update_flags(fsn_mark, fan_flags);
1141 spin_unlock(&fsn_mark->lock);
1142
1143 return recalc;
1144}
1145
1146static struct fsnotify_mark *fanotify_add_new_mark(struct fsnotify_group *group,
1147 fsnotify_connp_t *connp,
1148 unsigned int obj_type,
1149 unsigned int fan_flags,
1150 __kernel_fsid_t *fsid)
1151{
1152 struct ucounts *ucounts = group->fanotify_data.ucounts;
1153 struct fsnotify_mark *mark;
1154 int ret;
1155
1156 /*
1157 * Enforce per user marks limits per user in all containing user ns.
1158 * A group with FAN_UNLIMITED_MARKS does not contribute to mark count
1159 * in the limited groups account.
1160 */
1161 if (!FAN_GROUP_FLAG(group, FAN_UNLIMITED_MARKS) &&
1162 !inc_ucount(ucounts->ns, ucounts->uid, UCOUNT_FANOTIFY_MARKS))
1163 return ERR_PTR(-ENOSPC);
1164
1165 mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL);
1166 if (!mark) {
1167 ret = -ENOMEM;
1168 goto out_dec_ucounts;
1169 }
1170
1171 fsnotify_init_mark(mark, group);
1172 if (fan_flags & FAN_MARK_EVICTABLE)
1173 mark->flags |= FSNOTIFY_MARK_FLAG_NO_IREF;
1174
1175 ret = fsnotify_add_mark_locked(mark, connp, obj_type, 0, fsid);
1176 if (ret) {
1177 fsnotify_put_mark(mark);
1178 goto out_dec_ucounts;
1179 }
1180
1181 return mark;
1182
1183out_dec_ucounts:
1184 if (!FAN_GROUP_FLAG(group, FAN_UNLIMITED_MARKS))
1185 dec_ucount(ucounts, UCOUNT_FANOTIFY_MARKS);
1186 return ERR_PTR(ret);
1187}
1188
1189static int fanotify_group_init_error_pool(struct fsnotify_group *group)
1190{
1191 if (mempool_initialized(&group->fanotify_data.error_events_pool))
1192 return 0;
1193
1194 return mempool_init_kmalloc_pool(&group->fanotify_data.error_events_pool,
1195 FANOTIFY_DEFAULT_FEE_POOL_SIZE,
1196 sizeof(struct fanotify_error_event));
1197}
1198
1199static int fanotify_may_update_existing_mark(struct fsnotify_mark *fsn_mark,
1200 unsigned int fan_flags)
1201{
1202 /*
1203 * Non evictable mark cannot be downgraded to evictable mark.
1204 */
1205 if (fan_flags & FAN_MARK_EVICTABLE &&
1206 !(fsn_mark->flags & FSNOTIFY_MARK_FLAG_NO_IREF))
1207 return -EEXIST;
1208
1209 /*
1210 * New ignore mask semantics cannot be downgraded to old semantics.
1211 */
1212 if (fan_flags & FAN_MARK_IGNORED_MASK &&
1213 fsn_mark->flags & FSNOTIFY_MARK_FLAG_HAS_IGNORE_FLAGS)
1214 return -EEXIST;
1215
1216 /*
1217 * An ignore mask that survives modify could never be downgraded to not
1218 * survive modify. With new FAN_MARK_IGNORE semantics we make that rule
1219 * explicit and return an error when trying to update the ignore mask
1220 * without the original FAN_MARK_IGNORED_SURV_MODIFY value.
1221 */
1222 if (fan_flags & FAN_MARK_IGNORE &&
1223 !(fan_flags & FAN_MARK_IGNORED_SURV_MODIFY) &&
1224 fsn_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY)
1225 return -EEXIST;
1226
1227 return 0;
1228}
1229
1230static int fanotify_add_mark(struct fsnotify_group *group,
1231 fsnotify_connp_t *connp, unsigned int obj_type,
1232 __u32 mask, unsigned int fan_flags,
1233 __kernel_fsid_t *fsid)
1234{
1235 struct fsnotify_mark *fsn_mark;
1236 bool recalc;
1237 int ret = 0;
1238
1239 fsnotify_group_lock(group);
1240 fsn_mark = fsnotify_find_mark(connp, group);
1241 if (!fsn_mark) {
1242 fsn_mark = fanotify_add_new_mark(group, connp, obj_type,
1243 fan_flags, fsid);
1244 if (IS_ERR(fsn_mark)) {
1245 fsnotify_group_unlock(group);
1246 return PTR_ERR(fsn_mark);
1247 }
1248 }
1249
1250 /*
1251 * Check if requested mark flags conflict with an existing mark flags.
1252 */
1253 ret = fanotify_may_update_existing_mark(fsn_mark, fan_flags);
1254 if (ret)
1255 goto out;
1256
1257 /*
1258 * Error events are pre-allocated per group, only if strictly
1259 * needed (i.e. FAN_FS_ERROR was requested).
1260 */
1261 if (!(fan_flags & FANOTIFY_MARK_IGNORE_BITS) &&
1262 (mask & FAN_FS_ERROR)) {
1263 ret = fanotify_group_init_error_pool(group);
1264 if (ret)
1265 goto out;
1266 }
1267
1268 recalc = fanotify_mark_add_to_mask(fsn_mark, mask, fan_flags);
1269 if (recalc)
1270 fsnotify_recalc_mask(fsn_mark->connector);
1271
1272out:
1273 fsnotify_group_unlock(group);
1274
1275 fsnotify_put_mark(fsn_mark);
1276 return ret;
1277}
1278
1279static int fanotify_add_vfsmount_mark(struct fsnotify_group *group,
1280 struct vfsmount *mnt, __u32 mask,
1281 unsigned int flags, __kernel_fsid_t *fsid)
1282{
1283 return fanotify_add_mark(group, &real_mount(mnt)->mnt_fsnotify_marks,
1284 FSNOTIFY_OBJ_TYPE_VFSMOUNT, mask, flags, fsid);
1285}
1286
1287static int fanotify_add_sb_mark(struct fsnotify_group *group,
1288 struct super_block *sb, __u32 mask,
1289 unsigned int flags, __kernel_fsid_t *fsid)
1290{
1291 return fanotify_add_mark(group, &sb->s_fsnotify_marks,
1292 FSNOTIFY_OBJ_TYPE_SB, mask, flags, fsid);
1293}
1294
1295static int fanotify_add_inode_mark(struct fsnotify_group *group,
1296 struct inode *inode, __u32 mask,
1297 unsigned int flags, __kernel_fsid_t *fsid)
1298{
1299 pr_debug("%s: group=%p inode=%p\n", __func__, group, inode);
1300
1301 /*
1302 * If some other task has this inode open for write we should not add
1303 * an ignore mask, unless that ignore mask is supposed to survive
1304 * modification changes anyway.
1305 */
1306 if ((flags & FANOTIFY_MARK_IGNORE_BITS) &&
1307 !(flags & FAN_MARK_IGNORED_SURV_MODIFY) &&
1308 inode_is_open_for_write(inode))
1309 return 0;
1310
1311 return fanotify_add_mark(group, &inode->i_fsnotify_marks,
1312 FSNOTIFY_OBJ_TYPE_INODE, mask, flags, fsid);
1313}
1314
1315static struct fsnotify_event *fanotify_alloc_overflow_event(void)
1316{
1317 struct fanotify_event *oevent;
1318
1319 oevent = kmalloc(sizeof(*oevent), GFP_KERNEL_ACCOUNT);
1320 if (!oevent)
1321 return NULL;
1322
1323 fanotify_init_event(oevent, 0, FS_Q_OVERFLOW);
1324 oevent->type = FANOTIFY_EVENT_TYPE_OVERFLOW;
1325
1326 return &oevent->fse;
1327}
1328
1329static struct hlist_head *fanotify_alloc_merge_hash(void)
1330{
1331 struct hlist_head *hash;
1332
1333 hash = kmalloc(sizeof(struct hlist_head) << FANOTIFY_HTABLE_BITS,
1334 GFP_KERNEL_ACCOUNT);
1335 if (!hash)
1336 return NULL;
1337
1338 __hash_init(hash, FANOTIFY_HTABLE_SIZE);
1339
1340 return hash;
1341}
1342
1343/* fanotify syscalls */
1344SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
1345{
1346 struct fsnotify_group *group;
1347 int f_flags, fd;
1348 unsigned int fid_mode = flags & FANOTIFY_FID_BITS;
1349 unsigned int class = flags & FANOTIFY_CLASS_BITS;
1350 unsigned int internal_flags = 0;
1351
1352 pr_debug("%s: flags=%x event_f_flags=%x\n",
1353 __func__, flags, event_f_flags);
1354
1355 if (!capable(CAP_SYS_ADMIN)) {
1356 /*
1357 * An unprivileged user can setup an fanotify group with
1358 * limited functionality - an unprivileged group is limited to
1359 * notification events with file handles and it cannot use
1360 * unlimited queue/marks.
1361 */
1362 if ((flags & FANOTIFY_ADMIN_INIT_FLAGS) || !fid_mode)
1363 return -EPERM;
1364
1365 /*
1366 * Setting the internal flag FANOTIFY_UNPRIV on the group
1367 * prevents setting mount/filesystem marks on this group and
1368 * prevents reporting pid and open fd in events.
1369 */
1370 internal_flags |= FANOTIFY_UNPRIV;
1371 }
1372
1373#ifdef CONFIG_AUDITSYSCALL
1374 if (flags & ~(FANOTIFY_INIT_FLAGS | FAN_ENABLE_AUDIT))
1375#else
1376 if (flags & ~FANOTIFY_INIT_FLAGS)
1377#endif
1378 return -EINVAL;
1379
1380 /*
1381 * A pidfd can only be returned for a thread-group leader; thus
1382 * FAN_REPORT_PIDFD and FAN_REPORT_TID need to remain mutually
1383 * exclusive.
1384 */
1385 if ((flags & FAN_REPORT_PIDFD) && (flags & FAN_REPORT_TID))
1386 return -EINVAL;
1387
1388 if (event_f_flags & ~FANOTIFY_INIT_ALL_EVENT_F_BITS)
1389 return -EINVAL;
1390
1391 switch (event_f_flags & O_ACCMODE) {
1392 case O_RDONLY:
1393 case O_RDWR:
1394 case O_WRONLY:
1395 break;
1396 default:
1397 return -EINVAL;
1398 }
1399
1400 if (fid_mode && class != FAN_CLASS_NOTIF)
1401 return -EINVAL;
1402
1403 /*
1404 * Child name is reported with parent fid so requires dir fid.
1405 * We can report both child fid and dir fid with or without name.
1406 */
1407 if ((fid_mode & FAN_REPORT_NAME) && !(fid_mode & FAN_REPORT_DIR_FID))
1408 return -EINVAL;
1409
1410 /*
1411 * FAN_REPORT_TARGET_FID requires FAN_REPORT_NAME and FAN_REPORT_FID
1412 * and is used as an indication to report both dir and child fid on all
1413 * dirent events.
1414 */
1415 if ((fid_mode & FAN_REPORT_TARGET_FID) &&
1416 (!(fid_mode & FAN_REPORT_NAME) || !(fid_mode & FAN_REPORT_FID)))
1417 return -EINVAL;
1418
1419 f_flags = O_RDWR | __FMODE_NONOTIFY;
1420 if (flags & FAN_CLOEXEC)
1421 f_flags |= O_CLOEXEC;
1422 if (flags & FAN_NONBLOCK)
1423 f_flags |= O_NONBLOCK;
1424
1425 /* fsnotify_alloc_group takes a ref. Dropped in fanotify_release */
1426 group = fsnotify_alloc_group(&fanotify_fsnotify_ops,
1427 FSNOTIFY_GROUP_USER | FSNOTIFY_GROUP_NOFS);
1428 if (IS_ERR(group)) {
1429 return PTR_ERR(group);
1430 }
1431
1432 /* Enforce groups limits per user in all containing user ns */
1433 group->fanotify_data.ucounts = inc_ucount(current_user_ns(),
1434 current_euid(),
1435 UCOUNT_FANOTIFY_GROUPS);
1436 if (!group->fanotify_data.ucounts) {
1437 fd = -EMFILE;
1438 goto out_destroy_group;
1439 }
1440
1441 group->fanotify_data.flags = flags | internal_flags;
1442 group->memcg = get_mem_cgroup_from_mm(current->mm);
1443
1444 group->fanotify_data.merge_hash = fanotify_alloc_merge_hash();
1445 if (!group->fanotify_data.merge_hash) {
1446 fd = -ENOMEM;
1447 goto out_destroy_group;
1448 }
1449
1450 group->overflow_event = fanotify_alloc_overflow_event();
1451 if (unlikely(!group->overflow_event)) {
1452 fd = -ENOMEM;
1453 goto out_destroy_group;
1454 }
1455
1456 if (force_o_largefile())
1457 event_f_flags |= O_LARGEFILE;
1458 group->fanotify_data.f_flags = event_f_flags;
1459 init_waitqueue_head(&group->fanotify_data.access_waitq);
1460 INIT_LIST_HEAD(&group->fanotify_data.access_list);
1461 switch (class) {
1462 case FAN_CLASS_NOTIF:
1463 group->priority = FS_PRIO_0;
1464 break;
1465 case FAN_CLASS_CONTENT:
1466 group->priority = FS_PRIO_1;
1467 break;
1468 case FAN_CLASS_PRE_CONTENT:
1469 group->priority = FS_PRIO_2;
1470 break;
1471 default:
1472 fd = -EINVAL;
1473 goto out_destroy_group;
1474 }
1475
1476 if (flags & FAN_UNLIMITED_QUEUE) {
1477 fd = -EPERM;
1478 if (!capable(CAP_SYS_ADMIN))
1479 goto out_destroy_group;
1480 group->max_events = UINT_MAX;
1481 } else {
1482 group->max_events = fanotify_max_queued_events;
1483 }
1484
1485 if (flags & FAN_UNLIMITED_MARKS) {
1486 fd = -EPERM;
1487 if (!capable(CAP_SYS_ADMIN))
1488 goto out_destroy_group;
1489 }
1490
1491 if (flags & FAN_ENABLE_AUDIT) {
1492 fd = -EPERM;
1493 if (!capable(CAP_AUDIT_WRITE))
1494 goto out_destroy_group;
1495 }
1496
1497 fd = anon_inode_getfd("[fanotify]", &fanotify_fops, group, f_flags);
1498 if (fd < 0)
1499 goto out_destroy_group;
1500
1501 return fd;
1502
1503out_destroy_group:
1504 fsnotify_destroy_group(group);
1505 return fd;
1506}
1507
1508static int fanotify_test_fsid(struct dentry *dentry, __kernel_fsid_t *fsid)
1509{
1510 __kernel_fsid_t root_fsid;
1511 int err;
1512
1513 /*
1514 * Make sure dentry is not of a filesystem with zero fsid (e.g. fuse).
1515 */
1516 err = vfs_get_fsid(dentry, fsid);
1517 if (err)
1518 return err;
1519
1520 if (!fsid->val[0] && !fsid->val[1])
1521 return -ENODEV;
1522
1523 /*
1524 * Make sure dentry is not of a filesystem subvolume (e.g. btrfs)
1525 * which uses a different fsid than sb root.
1526 */
1527 err = vfs_get_fsid(dentry->d_sb->s_root, &root_fsid);
1528 if (err)
1529 return err;
1530
1531 if (root_fsid.val[0] != fsid->val[0] ||
1532 root_fsid.val[1] != fsid->val[1])
1533 return -EXDEV;
1534
1535 return 0;
1536}
1537
1538/* Check if filesystem can encode a unique fid */
1539static int fanotify_test_fid(struct dentry *dentry)
1540{
1541 /*
1542 * We need to make sure that the file system supports at least
1543 * encoding a file handle so user can use name_to_handle_at() to
1544 * compare fid returned with event to the file handle of watched
1545 * objects. However, name_to_handle_at() requires that the
1546 * filesystem also supports decoding file handles.
1547 */
1548 if (!dentry->d_sb->s_export_op ||
1549 !dentry->d_sb->s_export_op->fh_to_dentry)
1550 return -EOPNOTSUPP;
1551
1552 return 0;
1553}
1554
1555static int fanotify_events_supported(struct fsnotify_group *group,
1556 const struct path *path, __u64 mask,
1557 unsigned int flags)
1558{
1559 unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS;
1560 /* Strict validation of events in non-dir inode mask with v5.17+ APIs */
1561 bool strict_dir_events = FAN_GROUP_FLAG(group, FAN_REPORT_TARGET_FID) ||
1562 (mask & FAN_RENAME) ||
1563 (flags & FAN_MARK_IGNORE);
1564
1565 /*
1566 * Some filesystems such as 'proc' acquire unusual locks when opening
1567 * files. For them fanotify permission events have high chances of
1568 * deadlocking the system - open done when reporting fanotify event
1569 * blocks on this "unusual" lock while another process holding the lock
1570 * waits for fanotify permission event to be answered. Just disallow
1571 * permission events for such filesystems.
1572 */
1573 if (mask & FANOTIFY_PERM_EVENTS &&
1574 path->mnt->mnt_sb->s_type->fs_flags & FS_DISALLOW_NOTIFY_PERM)
1575 return -EINVAL;
1576
1577 /*
1578 * We shouldn't have allowed setting dirent events and the directory
1579 * flags FAN_ONDIR and FAN_EVENT_ON_CHILD in mask of non-dir inode,
1580 * but because we always allowed it, error only when using new APIs.
1581 */
1582 if (strict_dir_events && mark_type == FAN_MARK_INODE &&
1583 !d_is_dir(path->dentry) && (mask & FANOTIFY_DIRONLY_EVENT_BITS))
1584 return -ENOTDIR;
1585
1586 return 0;
1587}
1588
1589static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
1590 int dfd, const char __user *pathname)
1591{
1592 struct inode *inode = NULL;
1593 struct vfsmount *mnt = NULL;
1594 struct fsnotify_group *group;
1595 struct fd f;
1596 struct path path;
1597 __kernel_fsid_t __fsid, *fsid = NULL;
1598 u32 valid_mask = FANOTIFY_EVENTS | FANOTIFY_EVENT_FLAGS;
1599 unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS;
1600 unsigned int mark_cmd = flags & FANOTIFY_MARK_CMD_BITS;
1601 unsigned int ignore = flags & FANOTIFY_MARK_IGNORE_BITS;
1602 unsigned int obj_type, fid_mode;
1603 u32 umask = 0;
1604 int ret;
1605
1606 pr_debug("%s: fanotify_fd=%d flags=%x dfd=%d pathname=%p mask=%llx\n",
1607 __func__, fanotify_fd, flags, dfd, pathname, mask);
1608
1609 /* we only use the lower 32 bits as of right now. */
1610 if (upper_32_bits(mask))
1611 return -EINVAL;
1612
1613 if (flags & ~FANOTIFY_MARK_FLAGS)
1614 return -EINVAL;
1615
1616 switch (mark_type) {
1617 case FAN_MARK_INODE:
1618 obj_type = FSNOTIFY_OBJ_TYPE_INODE;
1619 break;
1620 case FAN_MARK_MOUNT:
1621 obj_type = FSNOTIFY_OBJ_TYPE_VFSMOUNT;
1622 break;
1623 case FAN_MARK_FILESYSTEM:
1624 obj_type = FSNOTIFY_OBJ_TYPE_SB;
1625 break;
1626 default:
1627 return -EINVAL;
1628 }
1629
1630 switch (mark_cmd) {
1631 case FAN_MARK_ADD:
1632 case FAN_MARK_REMOVE:
1633 if (!mask)
1634 return -EINVAL;
1635 break;
1636 case FAN_MARK_FLUSH:
1637 if (flags & ~(FANOTIFY_MARK_TYPE_BITS | FAN_MARK_FLUSH))
1638 return -EINVAL;
1639 break;
1640 default:
1641 return -EINVAL;
1642 }
1643
1644 if (IS_ENABLED(CONFIG_FANOTIFY_ACCESS_PERMISSIONS))
1645 valid_mask |= FANOTIFY_PERM_EVENTS;
1646
1647 if (mask & ~valid_mask)
1648 return -EINVAL;
1649
1650
1651 /* We don't allow FAN_MARK_IGNORE & FAN_MARK_IGNORED_MASK together */
1652 if (ignore == (FAN_MARK_IGNORE | FAN_MARK_IGNORED_MASK))
1653 return -EINVAL;
1654
1655 /*
1656 * Event flags (FAN_ONDIR, FAN_EVENT_ON_CHILD) have no effect with
1657 * FAN_MARK_IGNORED_MASK.
1658 */
1659 if (ignore == FAN_MARK_IGNORED_MASK) {
1660 mask &= ~FANOTIFY_EVENT_FLAGS;
1661 umask = FANOTIFY_EVENT_FLAGS;
1662 }
1663
1664 f = fdget(fanotify_fd);
1665 if (unlikely(!f.file))
1666 return -EBADF;
1667
1668 /* verify that this is indeed an fanotify instance */
1669 ret = -EINVAL;
1670 if (unlikely(f.file->f_op != &fanotify_fops))
1671 goto fput_and_out;
1672 group = f.file->private_data;
1673
1674 /*
1675 * An unprivileged user is not allowed to setup mount nor filesystem
1676 * marks. This also includes setting up such marks by a group that
1677 * was initialized by an unprivileged user.
1678 */
1679 ret = -EPERM;
1680 if ((!capable(CAP_SYS_ADMIN) ||
1681 FAN_GROUP_FLAG(group, FANOTIFY_UNPRIV)) &&
1682 mark_type != FAN_MARK_INODE)
1683 goto fput_and_out;
1684
1685 /*
1686 * group->priority == FS_PRIO_0 == FAN_CLASS_NOTIF. These are not
1687 * allowed to set permissions events.
1688 */
1689 ret = -EINVAL;
1690 if (mask & FANOTIFY_PERM_EVENTS &&
1691 group->priority == FS_PRIO_0)
1692 goto fput_and_out;
1693
1694 if (mask & FAN_FS_ERROR &&
1695 mark_type != FAN_MARK_FILESYSTEM)
1696 goto fput_and_out;
1697
1698 /*
1699 * Evictable is only relevant for inode marks, because only inode object
1700 * can be evicted on memory pressure.
1701 */
1702 if (flags & FAN_MARK_EVICTABLE &&
1703 mark_type != FAN_MARK_INODE)
1704 goto fput_and_out;
1705
1706 /*
1707 * Events that do not carry enough information to report
1708 * event->fd require a group that supports reporting fid. Those
1709 * events are not supported on a mount mark, because they do not
1710 * carry enough information (i.e. path) to be filtered by mount
1711 * point.
1712 */
1713 fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
1714 if (mask & ~(FANOTIFY_FD_EVENTS|FANOTIFY_EVENT_FLAGS) &&
1715 (!fid_mode || mark_type == FAN_MARK_MOUNT))
1716 goto fput_and_out;
1717
1718 /*
1719 * FAN_RENAME uses special info type records to report the old and
1720 * new parent+name. Reporting only old and new parent id is less
1721 * useful and was not implemented.
1722 */
1723 if (mask & FAN_RENAME && !(fid_mode & FAN_REPORT_NAME))
1724 goto fput_and_out;
1725
1726 if (mark_cmd == FAN_MARK_FLUSH) {
1727 ret = 0;
1728 if (mark_type == FAN_MARK_MOUNT)
1729 fsnotify_clear_vfsmount_marks_by_group(group);
1730 else if (mark_type == FAN_MARK_FILESYSTEM)
1731 fsnotify_clear_sb_marks_by_group(group);
1732 else
1733 fsnotify_clear_inode_marks_by_group(group);
1734 goto fput_and_out;
1735 }
1736
1737 ret = fanotify_find_path(dfd, pathname, &path, flags,
1738 (mask & ALL_FSNOTIFY_EVENTS), obj_type);
1739 if (ret)
1740 goto fput_and_out;
1741
1742 if (mark_cmd == FAN_MARK_ADD) {
1743 ret = fanotify_events_supported(group, &path, mask, flags);
1744 if (ret)
1745 goto path_put_and_out;
1746 }
1747
1748 if (fid_mode) {
1749 ret = fanotify_test_fsid(path.dentry, &__fsid);
1750 if (ret)
1751 goto path_put_and_out;
1752
1753 ret = fanotify_test_fid(path.dentry);
1754 if (ret)
1755 goto path_put_and_out;
1756
1757 fsid = &__fsid;
1758 }
1759
1760 /* inode held in place by reference to path; group by fget on fd */
1761 if (mark_type == FAN_MARK_INODE)
1762 inode = path.dentry->d_inode;
1763 else
1764 mnt = path.mnt;
1765
1766 ret = mnt ? -EINVAL : -EISDIR;
1767 /* FAN_MARK_IGNORE requires SURV_MODIFY for sb/mount/dir marks */
1768 if (mark_cmd == FAN_MARK_ADD && ignore == FAN_MARK_IGNORE &&
1769 (mnt || S_ISDIR(inode->i_mode)) &&
1770 !(flags & FAN_MARK_IGNORED_SURV_MODIFY))
1771 goto path_put_and_out;
1772
1773 /* Mask out FAN_EVENT_ON_CHILD flag for sb/mount/non-dir marks */
1774 if (mnt || !S_ISDIR(inode->i_mode)) {
1775 mask &= ~FAN_EVENT_ON_CHILD;
1776 umask = FAN_EVENT_ON_CHILD;
1777 /*
1778 * If group needs to report parent fid, register for getting
1779 * events with parent/name info for non-directory.
1780 */
1781 if ((fid_mode & FAN_REPORT_DIR_FID) &&
1782 (flags & FAN_MARK_ADD) && !ignore)
1783 mask |= FAN_EVENT_ON_CHILD;
1784 }
1785
1786 /* create/update an inode mark */
1787 switch (mark_cmd) {
1788 case FAN_MARK_ADD:
1789 if (mark_type == FAN_MARK_MOUNT)
1790 ret = fanotify_add_vfsmount_mark(group, mnt, mask,
1791 flags, fsid);
1792 else if (mark_type == FAN_MARK_FILESYSTEM)
1793 ret = fanotify_add_sb_mark(group, mnt->mnt_sb, mask,
1794 flags, fsid);
1795 else
1796 ret = fanotify_add_inode_mark(group, inode, mask,
1797 flags, fsid);
1798 break;
1799 case FAN_MARK_REMOVE:
1800 if (mark_type == FAN_MARK_MOUNT)
1801 ret = fanotify_remove_vfsmount_mark(group, mnt, mask,
1802 flags, umask);
1803 else if (mark_type == FAN_MARK_FILESYSTEM)
1804 ret = fanotify_remove_sb_mark(group, mnt->mnt_sb, mask,
1805 flags, umask);
1806 else
1807 ret = fanotify_remove_inode_mark(group, inode, mask,
1808 flags, umask);
1809 break;
1810 default:
1811 ret = -EINVAL;
1812 }
1813
1814path_put_and_out:
1815 path_put(&path);
1816fput_and_out:
1817 fdput(f);
1818 return ret;
1819}
1820
1821#ifndef CONFIG_ARCH_SPLIT_ARG64
1822SYSCALL_DEFINE5(fanotify_mark, int, fanotify_fd, unsigned int, flags,
1823 __u64, mask, int, dfd,
1824 const char __user *, pathname)
1825{
1826 return do_fanotify_mark(fanotify_fd, flags, mask, dfd, pathname);
1827}
1828#endif
1829
1830#if defined(CONFIG_ARCH_SPLIT_ARG64) || defined(CONFIG_COMPAT)
1831SYSCALL32_DEFINE6(fanotify_mark,
1832 int, fanotify_fd, unsigned int, flags,
1833 SC_ARG64(mask), int, dfd,
1834 const char __user *, pathname)
1835{
1836 return do_fanotify_mark(fanotify_fd, flags, SC_VAL64(__u64, mask),
1837 dfd, pathname);
1838}
1839#endif
1840
1841/*
1842 * fanotify_user_setup - Our initialization function. Note that we cannot return
1843 * error because we have compiled-in VFS hooks. So an (unlikely) failure here
1844 * must result in panic().
1845 */
1846static int __init fanotify_user_setup(void)
1847{
1848 struct sysinfo si;
1849 int max_marks;
1850
1851 si_meminfo(&si);
1852 /*
1853 * Allow up to 1% of addressable memory to be accounted for per user
1854 * marks limited to the range [8192, 1048576]. mount and sb marks are
1855 * a lot cheaper than inode marks, but there is no reason for a user
1856 * to have many of those, so calculate by the cost of inode marks.
1857 */
1858 max_marks = (((si.totalram - si.totalhigh) / 100) << PAGE_SHIFT) /
1859 INODE_MARK_COST;
1860 max_marks = clamp(max_marks, FANOTIFY_OLD_DEFAULT_MAX_MARKS,
1861 FANOTIFY_DEFAULT_MAX_USER_MARKS);
1862
1863 BUILD_BUG_ON(FANOTIFY_INIT_FLAGS & FANOTIFY_INTERNAL_GROUP_FLAGS);
1864 BUILD_BUG_ON(HWEIGHT32(FANOTIFY_INIT_FLAGS) != 12);
1865 BUILD_BUG_ON(HWEIGHT32(FANOTIFY_MARK_FLAGS) != 11);
1866
1867 fanotify_mark_cache = KMEM_CACHE(fsnotify_mark,
1868 SLAB_PANIC|SLAB_ACCOUNT);
1869 fanotify_fid_event_cachep = KMEM_CACHE(fanotify_fid_event,
1870 SLAB_PANIC);
1871 fanotify_path_event_cachep = KMEM_CACHE(fanotify_path_event,
1872 SLAB_PANIC);
1873 if (IS_ENABLED(CONFIG_FANOTIFY_ACCESS_PERMISSIONS)) {
1874 fanotify_perm_event_cachep =
1875 KMEM_CACHE(fanotify_perm_event, SLAB_PANIC);
1876 }
1877
1878 fanotify_max_queued_events = FANOTIFY_DEFAULT_MAX_EVENTS;
1879 init_user_ns.ucount_max[UCOUNT_FANOTIFY_GROUPS] =
1880 FANOTIFY_DEFAULT_MAX_GROUPS;
1881 init_user_ns.ucount_max[UCOUNT_FANOTIFY_MARKS] = max_marks;
1882 fanotify_sysctls_init();
1883
1884 return 0;
1885}
1886device_initcall(fanotify_user_setup);