1
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#include <linux/memcontrol.h>
20#include <linux/statfs.h>
21#include <linux/exportfs.h>
22
23#include <asm/ioctls.h>
24
25#include "../../mount.h"
26#include "../fdinfo.h"
27#include "fanotify.h"
28
29#define FANOTIFY_DEFAULT_MAX_EVENTS 16384
30#define FANOTIFY_OLD_DEFAULT_MAX_MARKS 8192
31#define FANOTIFY_DEFAULT_MAX_GROUPS 128
32
33
34
35
36
37
38
39
40#define FANOTIFY_DEFAULT_MAX_USER_MARKS \
41 (FANOTIFY_OLD_DEFAULT_MAX_MARKS * FANOTIFY_DEFAULT_MAX_GROUPS)
42
43
44
45
46
47
48#define INODE_MARK_COST (2 * sizeof(struct inode))
49
50
51static int fanotify_max_queued_events __read_mostly;
52
53#ifdef CONFIG_SYSCTL
54
55#include <linux/sysctl.h>
56
57static long ft_zero = 0;
58static long ft_int_max = INT_MAX;
59
60struct ctl_table fanotify_table[] = {
61 {
62 .procname = "max_user_groups",
63 .data = &init_user_ns.ucount_max[UCOUNT_FANOTIFY_GROUPS],
64 .maxlen = sizeof(long),
65 .mode = 0644,
66 .proc_handler = proc_doulongvec_minmax,
67 .extra1 = &ft_zero,
68 .extra2 = &ft_int_max,
69 },
70 {
71 .procname = "max_user_marks",
72 .data = &init_user_ns.ucount_max[UCOUNT_FANOTIFY_MARKS],
73 .maxlen = sizeof(long),
74 .mode = 0644,
75 .proc_handler = proc_doulongvec_minmax,
76 .extra1 = &ft_zero,
77 .extra2 = &ft_int_max,
78 },
79 {
80 .procname = "max_queued_events",
81 .data = &fanotify_max_queued_events,
82 .maxlen = sizeof(int),
83 .mode = 0644,
84 .proc_handler = proc_dointvec_minmax,
85 .extra1 = SYSCTL_ZERO
86 },
87 { }
88};
89#endif
90
91
92
93
94
95
96
97
98
99#define FANOTIFY_INIT_ALL_EVENT_F_BITS ( \
100 O_ACCMODE | O_APPEND | O_NONBLOCK | \
101 __O_SYNC | O_DSYNC | O_CLOEXEC | \
102 O_LARGEFILE | O_NOATIME )
103
104extern const struct fsnotify_ops fanotify_fsnotify_ops;
105
106struct kmem_cache *fanotify_mark_cache __read_mostly;
107struct kmem_cache *fanotify_fid_event_cachep __read_mostly;
108struct kmem_cache *fanotify_path_event_cachep __read_mostly;
109struct kmem_cache *fanotify_perm_event_cachep __read_mostly;
110
111#define FANOTIFY_EVENT_ALIGN 4
112#define FANOTIFY_INFO_HDR_LEN \
113 (sizeof(struct fanotify_event_info_fid) + sizeof(struct file_handle))
114
115static int fanotify_fid_info_len(int fh_len, int name_len)
116{
117 int info_len = fh_len;
118
119 if (name_len)
120 info_len += name_len + 1;
121
122 return roundup(FANOTIFY_INFO_HDR_LEN + info_len, FANOTIFY_EVENT_ALIGN);
123}
124
125static int fanotify_event_info_len(unsigned int fid_mode,
126 struct fanotify_event *event)
127{
128 struct fanotify_info *info = fanotify_event_info(event);
129 int dir_fh_len = fanotify_event_dir_fh_len(event);
130 int fh_len = fanotify_event_object_fh_len(event);
131 int info_len = 0;
132 int dot_len = 0;
133
134 if (dir_fh_len) {
135 info_len += fanotify_fid_info_len(dir_fh_len, info->name_len);
136 } else if ((fid_mode & FAN_REPORT_NAME) && (event->mask & FAN_ONDIR)) {
137
138
139
140
141 dot_len = 1;
142 }
143
144 if (fh_len)
145 info_len += fanotify_fid_info_len(fh_len, dot_len);
146
147 return info_len;
148}
149
150
151
152
153static void fanotify_unhash_event(struct fsnotify_group *group,
154 struct fanotify_event *event)
155{
156 assert_spin_locked(&group->notification_lock);
157
158 pr_debug("%s: group=%p event=%p bucket=%u\n", __func__,
159 group, event, fanotify_event_hash_bucket(group, event));
160
161 if (WARN_ON_ONCE(hlist_unhashed(&event->merge_list)))
162 return;
163
164 hlist_del_init(&event->merge_list);
165}
166
167
168
169
170
171
172
173static struct fanotify_event *get_one_event(struct fsnotify_group *group,
174 size_t count)
175{
176 size_t event_size = FAN_EVENT_METADATA_LEN;
177 struct fanotify_event *event = NULL;
178 struct fsnotify_event *fsn_event;
179 unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
180
181 pr_debug("%s: group=%p count=%zd\n", __func__, group, count);
182
183 spin_lock(&group->notification_lock);
184 fsn_event = fsnotify_peek_first_event(group);
185 if (!fsn_event)
186 goto out;
187
188 event = FANOTIFY_E(fsn_event);
189 if (fid_mode)
190 event_size += fanotify_event_info_len(fid_mode, event);
191
192 if (event_size > count) {
193 event = ERR_PTR(-EINVAL);
194 goto out;
195 }
196
197
198
199
200
201 fsnotify_remove_first_event(group);
202 if (fanotify_is_perm_event(event->mask))
203 FANOTIFY_PERM(event)->state = FAN_EVENT_REPORTED;
204 if (fanotify_is_hashed_event(event->mask))
205 fanotify_unhash_event(group, event);
206out:
207 spin_unlock(&group->notification_lock);
208 return event;
209}
210
211static int create_fd(struct fsnotify_group *group, struct path *path,
212 struct file **file)
213{
214 int client_fd;
215 struct file *new_file;
216
217 client_fd = get_unused_fd_flags(group->fanotify_data.f_flags);
218 if (client_fd < 0)
219 return client_fd;
220
221
222
223
224
225 new_file = dentry_open(path,
226 group->fanotify_data.f_flags | FMODE_NONOTIFY,
227 current_cred());
228 if (IS_ERR(new_file)) {
229
230
231
232
233
234
235
236 put_unused_fd(client_fd);
237 client_fd = PTR_ERR(new_file);
238 } else {
239 *file = new_file;
240 }
241
242 return client_fd;
243}
244
245
246
247
248
249static void finish_permission_event(struct fsnotify_group *group,
250 struct fanotify_perm_event *event,
251 unsigned int response)
252 __releases(&group->notification_lock)
253{
254 bool destroy = false;
255
256 assert_spin_locked(&group->notification_lock);
257 event->response = response;
258 if (event->state == FAN_EVENT_CANCELED)
259 destroy = true;
260 else
261 event->state = FAN_EVENT_ANSWERED;
262 spin_unlock(&group->notification_lock);
263 if (destroy)
264 fsnotify_destroy_event(group, &event->fae.fse);
265}
266
267static int process_access_response(struct fsnotify_group *group,
268 struct fanotify_response *response_struct)
269{
270 struct fanotify_perm_event *event;
271 int fd = response_struct->fd;
272 int response = response_struct->response;
273
274 pr_debug("%s: group=%p fd=%d response=%d\n", __func__, group,
275 fd, response);
276
277
278
279
280
281 switch (response & ~FAN_AUDIT) {
282 case FAN_ALLOW:
283 case FAN_DENY:
284 break;
285 default:
286 return -EINVAL;
287 }
288
289 if (fd < 0)
290 return -EINVAL;
291
292 if ((response & FAN_AUDIT) && !FAN_GROUP_FLAG(group, FAN_ENABLE_AUDIT))
293 return -EINVAL;
294
295 spin_lock(&group->notification_lock);
296 list_for_each_entry(event, &group->fanotify_data.access_list,
297 fae.fse.list) {
298 if (event->fd != fd)
299 continue;
300
301 list_del_init(&event->fae.fse.list);
302 finish_permission_event(group, event, response);
303 wake_up(&group->fanotify_data.access_waitq);
304 return 0;
305 }
306 spin_unlock(&group->notification_lock);
307
308 return -ENOENT;
309}
310
311static int copy_info_to_user(__kernel_fsid_t *fsid, struct fanotify_fh *fh,
312 int info_type, const char *name, size_t name_len,
313 char __user *buf, size_t count)
314{
315 struct fanotify_event_info_fid info = { };
316 struct file_handle handle = { };
317 unsigned char bounce[FANOTIFY_INLINE_FH_LEN], *fh_buf;
318 size_t fh_len = fh ? fh->len : 0;
319 size_t info_len = fanotify_fid_info_len(fh_len, name_len);
320 size_t len = info_len;
321
322 pr_debug("%s: fh_len=%zu name_len=%zu, info_len=%zu, count=%zu\n",
323 __func__, fh_len, name_len, info_len, count);
324
325 if (!fh_len)
326 return 0;
327
328 if (WARN_ON_ONCE(len < sizeof(info) || len > count))
329 return -EFAULT;
330
331
332
333
334
335 switch (info_type) {
336 case FAN_EVENT_INFO_TYPE_FID:
337 case FAN_EVENT_INFO_TYPE_DFID:
338 if (WARN_ON_ONCE(name_len))
339 return -EFAULT;
340 break;
341 case FAN_EVENT_INFO_TYPE_DFID_NAME:
342 if (WARN_ON_ONCE(!name || !name_len))
343 return -EFAULT;
344 break;
345 default:
346 return -EFAULT;
347 }
348
349 info.hdr.info_type = info_type;
350 info.hdr.len = len;
351 info.fsid = *fsid;
352 if (copy_to_user(buf, &info, sizeof(info)))
353 return -EFAULT;
354
355 buf += sizeof(info);
356 len -= sizeof(info);
357 if (WARN_ON_ONCE(len < sizeof(handle)))
358 return -EFAULT;
359
360 handle.handle_type = fh->type;
361 handle.handle_bytes = fh_len;
362 if (copy_to_user(buf, &handle, sizeof(handle)))
363 return -EFAULT;
364
365 buf += sizeof(handle);
366 len -= sizeof(handle);
367 if (WARN_ON_ONCE(len < fh_len))
368 return -EFAULT;
369
370
371
372
373
374 fh_buf = fanotify_fh_buf(fh);
375 if (fh_len <= FANOTIFY_INLINE_FH_LEN) {
376 memcpy(bounce, fh_buf, fh_len);
377 fh_buf = bounce;
378 }
379 if (copy_to_user(buf, fh_buf, fh_len))
380 return -EFAULT;
381
382 buf += fh_len;
383 len -= fh_len;
384
385 if (name_len) {
386
387 name_len++;
388 if (WARN_ON_ONCE(len < name_len))
389 return -EFAULT;
390
391 if (copy_to_user(buf, name, name_len))
392 return -EFAULT;
393
394 buf += name_len;
395 len -= name_len;
396 }
397
398
399 WARN_ON_ONCE(len < 0 || len >= FANOTIFY_EVENT_ALIGN);
400 if (len > 0 && clear_user(buf, len))
401 return -EFAULT;
402
403 return info_len;
404}
405
406static ssize_t copy_event_to_user(struct fsnotify_group *group,
407 struct fanotify_event *event,
408 char __user *buf, size_t count)
409{
410 struct fanotify_event_metadata metadata;
411 struct path *path = fanotify_event_path(event);
412 struct fanotify_info *info = fanotify_event_info(event);
413 unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
414 struct file *f = NULL;
415 int ret, fd = FAN_NOFD;
416 int info_type = 0;
417
418 pr_debug("%s: group=%p event=%p\n", __func__, group, event);
419
420 metadata.event_len = FAN_EVENT_METADATA_LEN +
421 fanotify_event_info_len(fid_mode, event);
422 metadata.metadata_len = FAN_EVENT_METADATA_LEN;
423 metadata.vers = FANOTIFY_METADATA_VERSION;
424 metadata.reserved = 0;
425 metadata.mask = event->mask & FANOTIFY_OUTGOING_EVENTS;
426 metadata.pid = pid_vnr(event->pid);
427
428
429
430
431
432 if (FAN_GROUP_FLAG(group, FANOTIFY_UNPRIV) &&
433 task_tgid(current) != event->pid)
434 metadata.pid = 0;
435
436
437
438
439
440
441
442 if (!FAN_GROUP_FLAG(group, FANOTIFY_UNPRIV) &&
443 path && path->mnt && path->dentry) {
444 fd = create_fd(group, path, &f);
445 if (fd < 0)
446 return fd;
447 }
448 metadata.fd = fd;
449
450 ret = -EFAULT;
451
452
453
454
455 if (WARN_ON_ONCE(metadata.event_len > count))
456 goto out_close_fd;
457
458 if (copy_to_user(buf, &metadata, FAN_EVENT_METADATA_LEN))
459 goto out_close_fd;
460
461 buf += FAN_EVENT_METADATA_LEN;
462 count -= FAN_EVENT_METADATA_LEN;
463
464 if (fanotify_is_perm_event(event->mask))
465 FANOTIFY_PERM(event)->fd = fd;
466
467 if (f)
468 fd_install(fd, f);
469
470
471 if (fanotify_event_dir_fh_len(event)) {
472 info_type = info->name_len ? FAN_EVENT_INFO_TYPE_DFID_NAME :
473 FAN_EVENT_INFO_TYPE_DFID;
474 ret = copy_info_to_user(fanotify_event_fsid(event),
475 fanotify_info_dir_fh(info),
476 info_type, fanotify_info_name(info),
477 info->name_len, buf, count);
478 if (ret < 0)
479 goto out_close_fd;
480
481 buf += ret;
482 count -= ret;
483 }
484
485 if (fanotify_event_object_fh_len(event)) {
486 const char *dot = NULL;
487 int dot_len = 0;
488
489 if (fid_mode == FAN_REPORT_FID || info_type) {
490
491
492
493
494 info_type = FAN_EVENT_INFO_TYPE_FID;
495 } else if ((fid_mode & FAN_REPORT_NAME) &&
496 (event->mask & FAN_ONDIR)) {
497
498
499
500
501
502 info_type = FAN_EVENT_INFO_TYPE_DFID_NAME;
503 dot = ".";
504 dot_len = 1;
505 } else if ((event->mask & ALL_FSNOTIFY_DIRENT_EVENTS) ||
506 (event->mask & FAN_ONDIR)) {
507
508
509
510
511
512 info_type = FAN_EVENT_INFO_TYPE_DFID;
513 } else {
514
515
516
517
518
519
520 info_type = FAN_EVENT_INFO_TYPE_FID;
521 }
522
523 ret = copy_info_to_user(fanotify_event_fsid(event),
524 fanotify_event_object_fh(event),
525 info_type, dot, dot_len, buf, count);
526 if (ret < 0)
527 goto out_close_fd;
528
529 buf += ret;
530 count -= ret;
531 }
532
533 return metadata.event_len;
534
535out_close_fd:
536 if (fd != FAN_NOFD) {
537 put_unused_fd(fd);
538 fput(f);
539 }
540 return ret;
541}
542
543
544static __poll_t fanotify_poll(struct file *file, poll_table *wait)
545{
546 struct fsnotify_group *group = file->private_data;
547 __poll_t ret = 0;
548
549 poll_wait(file, &group->notification_waitq, wait);
550 spin_lock(&group->notification_lock);
551 if (!fsnotify_notify_queue_is_empty(group))
552 ret = EPOLLIN | EPOLLRDNORM;
553 spin_unlock(&group->notification_lock);
554
555 return ret;
556}
557
558static ssize_t fanotify_read(struct file *file, char __user *buf,
559 size_t count, loff_t *pos)
560{
561 struct fsnotify_group *group;
562 struct fanotify_event *event;
563 char __user *start;
564 int ret;
565 DEFINE_WAIT_FUNC(wait, woken_wake_function);
566
567 start = buf;
568 group = file->private_data;
569
570 pr_debug("%s: group=%p\n", __func__, group);
571
572 add_wait_queue(&group->notification_waitq, &wait);
573 while (1) {
574
575
576
577
578 cond_resched();
579 event = get_one_event(group, count);
580 if (IS_ERR(event)) {
581 ret = PTR_ERR(event);
582 break;
583 }
584
585 if (!event) {
586 ret = -EAGAIN;
587 if (file->f_flags & O_NONBLOCK)
588 break;
589
590 ret = -ERESTARTSYS;
591 if (signal_pending(current))
592 break;
593
594 if (start != buf)
595 break;
596
597 wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
598 continue;
599 }
600
601 ret = copy_event_to_user(group, event, buf, count);
602 if (unlikely(ret == -EOPENSTALE)) {
603
604
605
606
607
608
609 ret = 0;
610 }
611
612
613
614
615
616 if (!fanotify_is_perm_event(event->mask)) {
617 fsnotify_destroy_event(group, &event->fse);
618 } else {
619 if (ret <= 0) {
620 spin_lock(&group->notification_lock);
621 finish_permission_event(group,
622 FANOTIFY_PERM(event), FAN_DENY);
623 wake_up(&group->fanotify_data.access_waitq);
624 } else {
625 spin_lock(&group->notification_lock);
626 list_add_tail(&event->fse.list,
627 &group->fanotify_data.access_list);
628 spin_unlock(&group->notification_lock);
629 }
630 }
631 if (ret < 0)
632 break;
633 buf += ret;
634 count -= ret;
635 }
636 remove_wait_queue(&group->notification_waitq, &wait);
637
638 if (start != buf && ret != -EFAULT)
639 ret = buf - start;
640 return ret;
641}
642
643static ssize_t fanotify_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)
644{
645 struct fanotify_response response = { .fd = -1, .response = -1 };
646 struct fsnotify_group *group;
647 int ret;
648
649 if (!IS_ENABLED(CONFIG_FANOTIFY_ACCESS_PERMISSIONS))
650 return -EINVAL;
651
652 group = file->private_data;
653
654 if (count < sizeof(response))
655 return -EINVAL;
656
657 count = sizeof(response);
658
659 pr_debug("%s: group=%p count=%zu\n", __func__, group, count);
660
661 if (copy_from_user(&response, buf, count))
662 return -EFAULT;
663
664 ret = process_access_response(group, &response);
665 if (ret < 0)
666 count = ret;
667
668 return count;
669}
670
671static int fanotify_release(struct inode *ignored, struct file *file)
672{
673 struct fsnotify_group *group = file->private_data;
674 struct fsnotify_event *fsn_event;
675
676
677
678
679
680
681 fsnotify_group_stop_queueing(group);
682
683
684
685
686
687 spin_lock(&group->notification_lock);
688 while (!list_empty(&group->fanotify_data.access_list)) {
689 struct fanotify_perm_event *event;
690
691 event = list_first_entry(&group->fanotify_data.access_list,
692 struct fanotify_perm_event, fae.fse.list);
693 list_del_init(&event->fae.fse.list);
694 finish_permission_event(group, event, FAN_ALLOW);
695 spin_lock(&group->notification_lock);
696 }
697
698
699
700
701
702
703 while ((fsn_event = fsnotify_remove_first_event(group))) {
704 struct fanotify_event *event = FANOTIFY_E(fsn_event);
705
706 if (!(event->mask & FANOTIFY_PERM_EVENTS)) {
707 spin_unlock(&group->notification_lock);
708 fsnotify_destroy_event(group, fsn_event);
709 } else {
710 finish_permission_event(group, FANOTIFY_PERM(event),
711 FAN_ALLOW);
712 }
713 spin_lock(&group->notification_lock);
714 }
715 spin_unlock(&group->notification_lock);
716
717
718 wake_up(&group->fanotify_data.access_waitq);
719
720
721 fsnotify_destroy_group(group);
722
723 return 0;
724}
725
726static long fanotify_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
727{
728 struct fsnotify_group *group;
729 struct fsnotify_event *fsn_event;
730 void __user *p;
731 int ret = -ENOTTY;
732 size_t send_len = 0;
733
734 group = file->private_data;
735
736 p = (void __user *) arg;
737
738 switch (cmd) {
739 case FIONREAD:
740 spin_lock(&group->notification_lock);
741 list_for_each_entry(fsn_event, &group->notification_list, list)
742 send_len += FAN_EVENT_METADATA_LEN;
743 spin_unlock(&group->notification_lock);
744 ret = put_user(send_len, (int __user *) p);
745 break;
746 }
747
748 return ret;
749}
750
751static const struct file_operations fanotify_fops = {
752 .show_fdinfo = fanotify_show_fdinfo,
753 .poll = fanotify_poll,
754 .read = fanotify_read,
755 .write = fanotify_write,
756 .fasync = NULL,
757 .release = fanotify_release,
758 .unlocked_ioctl = fanotify_ioctl,
759 .compat_ioctl = compat_ptr_ioctl,
760 .llseek = noop_llseek,
761};
762
763static int fanotify_find_path(int dfd, const char __user *filename,
764 struct path *path, unsigned int flags, __u64 mask,
765 unsigned int obj_type)
766{
767 int ret;
768
769 pr_debug("%s: dfd=%d filename=%p flags=%x\n", __func__,
770 dfd, filename, flags);
771
772 if (filename == NULL) {
773 struct fd f = fdget(dfd);
774
775 ret = -EBADF;
776 if (!f.file)
777 goto out;
778
779 ret = -ENOTDIR;
780 if ((flags & FAN_MARK_ONLYDIR) &&
781 !(S_ISDIR(file_inode(f.file)->i_mode))) {
782 fdput(f);
783 goto out;
784 }
785
786 *path = f.file->f_path;
787 path_get(path);
788 fdput(f);
789 } else {
790 unsigned int lookup_flags = 0;
791
792 if (!(flags & FAN_MARK_DONT_FOLLOW))
793 lookup_flags |= LOOKUP_FOLLOW;
794 if (flags & FAN_MARK_ONLYDIR)
795 lookup_flags |= LOOKUP_DIRECTORY;
796
797 ret = user_path_at(dfd, filename, lookup_flags, path);
798 if (ret)
799 goto out;
800 }
801
802
803 ret = path_permission(path, MAY_READ);
804 if (ret) {
805 path_put(path);
806 goto out;
807 }
808
809 ret = security_path_notify(path, mask, obj_type);
810 if (ret)
811 path_put(path);
812
813out:
814 return ret;
815}
816
817static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark,
818 __u32 mask, unsigned int flags,
819 __u32 umask, int *destroy)
820{
821 __u32 oldmask = 0;
822
823
824 mask &= ~umask;
825 spin_lock(&fsn_mark->lock);
826 if (!(flags & FAN_MARK_IGNORED_MASK)) {
827 oldmask = fsn_mark->mask;
828 fsn_mark->mask &= ~mask;
829 } else {
830 fsn_mark->ignored_mask &= ~mask;
831 }
832
833
834
835
836
837
838 *destroy = !((fsn_mark->mask | fsn_mark->ignored_mask) & ~umask);
839 spin_unlock(&fsn_mark->lock);
840
841 return mask & oldmask;
842}
843
844static int fanotify_remove_mark(struct fsnotify_group *group,
845 fsnotify_connp_t *connp, __u32 mask,
846 unsigned int flags, __u32 umask)
847{
848 struct fsnotify_mark *fsn_mark = NULL;
849 __u32 removed;
850 int destroy_mark;
851
852 mutex_lock(&group->mark_mutex);
853 fsn_mark = fsnotify_find_mark(connp, group);
854 if (!fsn_mark) {
855 mutex_unlock(&group->mark_mutex);
856 return -ENOENT;
857 }
858
859 removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags,
860 umask, &destroy_mark);
861 if (removed & fsnotify_conn_mask(fsn_mark->connector))
862 fsnotify_recalc_mask(fsn_mark->connector);
863 if (destroy_mark)
864 fsnotify_detach_mark(fsn_mark);
865 mutex_unlock(&group->mark_mutex);
866 if (destroy_mark)
867 fsnotify_free_mark(fsn_mark);
868
869
870 fsnotify_put_mark(fsn_mark);
871 return 0;
872}
873
874static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group,
875 struct vfsmount *mnt, __u32 mask,
876 unsigned int flags, __u32 umask)
877{
878 return fanotify_remove_mark(group, &real_mount(mnt)->mnt_fsnotify_marks,
879 mask, flags, umask);
880}
881
882static int fanotify_remove_sb_mark(struct fsnotify_group *group,
883 struct super_block *sb, __u32 mask,
884 unsigned int flags, __u32 umask)
885{
886 return fanotify_remove_mark(group, &sb->s_fsnotify_marks, mask,
887 flags, umask);
888}
889
890static int fanotify_remove_inode_mark(struct fsnotify_group *group,
891 struct inode *inode, __u32 mask,
892 unsigned int flags, __u32 umask)
893{
894 return fanotify_remove_mark(group, &inode->i_fsnotify_marks, mask,
895 flags, umask);
896}
897
898static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark,
899 __u32 mask,
900 unsigned int flags)
901{
902 __u32 oldmask = -1;
903
904 spin_lock(&fsn_mark->lock);
905 if (!(flags & FAN_MARK_IGNORED_MASK)) {
906 oldmask = fsn_mark->mask;
907 fsn_mark->mask |= mask;
908 } else {
909 fsn_mark->ignored_mask |= mask;
910 if (flags & FAN_MARK_IGNORED_SURV_MODIFY)
911 fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY;
912 }
913 spin_unlock(&fsn_mark->lock);
914
915 return mask & ~oldmask;
916}
917
918static struct fsnotify_mark *fanotify_add_new_mark(struct fsnotify_group *group,
919 fsnotify_connp_t *connp,
920 unsigned int type,
921 __kernel_fsid_t *fsid)
922{
923 struct ucounts *ucounts = group->fanotify_data.ucounts;
924 struct fsnotify_mark *mark;
925 int ret;
926
927
928
929
930
931
932 if (!FAN_GROUP_FLAG(group, FAN_UNLIMITED_MARKS) &&
933 !inc_ucount(ucounts->ns, ucounts->uid, UCOUNT_FANOTIFY_MARKS))
934 return ERR_PTR(-ENOSPC);
935
936 mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL);
937 if (!mark) {
938 ret = -ENOMEM;
939 goto out_dec_ucounts;
940 }
941
942 fsnotify_init_mark(mark, group);
943 ret = fsnotify_add_mark_locked(mark, connp, type, 0, fsid);
944 if (ret) {
945 fsnotify_put_mark(mark);
946 goto out_dec_ucounts;
947 }
948
949 return mark;
950
951out_dec_ucounts:
952 if (!FAN_GROUP_FLAG(group, FAN_UNLIMITED_MARKS))
953 dec_ucount(ucounts, UCOUNT_FANOTIFY_MARKS);
954 return ERR_PTR(ret);
955}
956
957
958static int fanotify_add_mark(struct fsnotify_group *group,
959 fsnotify_connp_t *connp, unsigned int type,
960 __u32 mask, unsigned int flags,
961 __kernel_fsid_t *fsid)
962{
963 struct fsnotify_mark *fsn_mark;
964 __u32 added;
965
966 mutex_lock(&group->mark_mutex);
967 fsn_mark = fsnotify_find_mark(connp, group);
968 if (!fsn_mark) {
969 fsn_mark = fanotify_add_new_mark(group, connp, type, fsid);
970 if (IS_ERR(fsn_mark)) {
971 mutex_unlock(&group->mark_mutex);
972 return PTR_ERR(fsn_mark);
973 }
974 }
975 added = fanotify_mark_add_to_mask(fsn_mark, mask, flags);
976 if (added & ~fsnotify_conn_mask(fsn_mark->connector))
977 fsnotify_recalc_mask(fsn_mark->connector);
978 mutex_unlock(&group->mark_mutex);
979
980 fsnotify_put_mark(fsn_mark);
981 return 0;
982}
983
984static int fanotify_add_vfsmount_mark(struct fsnotify_group *group,
985 struct vfsmount *mnt, __u32 mask,
986 unsigned int flags, __kernel_fsid_t *fsid)
987{
988 return fanotify_add_mark(group, &real_mount(mnt)->mnt_fsnotify_marks,
989 FSNOTIFY_OBJ_TYPE_VFSMOUNT, mask, flags, fsid);
990}
991
992static int fanotify_add_sb_mark(struct fsnotify_group *group,
993 struct super_block *sb, __u32 mask,
994 unsigned int flags, __kernel_fsid_t *fsid)
995{
996 return fanotify_add_mark(group, &sb->s_fsnotify_marks,
997 FSNOTIFY_OBJ_TYPE_SB, mask, flags, fsid);
998}
999
1000static int fanotify_add_inode_mark(struct fsnotify_group *group,
1001 struct inode *inode, __u32 mask,
1002 unsigned int flags, __kernel_fsid_t *fsid)
1003{
1004 pr_debug("%s: group=%p inode=%p\n", __func__, group, inode);
1005
1006
1007
1008
1009
1010
1011 if ((flags & FAN_MARK_IGNORED_MASK) &&
1012 !(flags & FAN_MARK_IGNORED_SURV_MODIFY) &&
1013 inode_is_open_for_write(inode))
1014 return 0;
1015
1016 return fanotify_add_mark(group, &inode->i_fsnotify_marks,
1017 FSNOTIFY_OBJ_TYPE_INODE, mask, flags, fsid);
1018}
1019
1020static struct fsnotify_event *fanotify_alloc_overflow_event(void)
1021{
1022 struct fanotify_event *oevent;
1023
1024 oevent = kmalloc(sizeof(*oevent), GFP_KERNEL_ACCOUNT);
1025 if (!oevent)
1026 return NULL;
1027
1028 fanotify_init_event(oevent, 0, FS_Q_OVERFLOW);
1029 oevent->type = FANOTIFY_EVENT_TYPE_OVERFLOW;
1030
1031 return &oevent->fse;
1032}
1033
1034static struct hlist_head *fanotify_alloc_merge_hash(void)
1035{
1036 struct hlist_head *hash;
1037
1038 hash = kmalloc(sizeof(struct hlist_head) << FANOTIFY_HTABLE_BITS,
1039 GFP_KERNEL_ACCOUNT);
1040 if (!hash)
1041 return NULL;
1042
1043 __hash_init(hash, FANOTIFY_HTABLE_SIZE);
1044
1045 return hash;
1046}
1047
1048
1049SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
1050{
1051 struct fsnotify_group *group;
1052 int f_flags, fd;
1053 unsigned int fid_mode = flags & FANOTIFY_FID_BITS;
1054 unsigned int class = flags & FANOTIFY_CLASS_BITS;
1055 unsigned int internal_flags = 0;
1056
1057 pr_debug("%s: flags=%x event_f_flags=%x\n",
1058 __func__, flags, event_f_flags);
1059
1060 if (!capable(CAP_SYS_ADMIN)) {
1061
1062
1063
1064
1065
1066
1067 if ((flags & FANOTIFY_ADMIN_INIT_FLAGS) || !fid_mode)
1068 return -EPERM;
1069
1070
1071
1072
1073
1074
1075 internal_flags |= FANOTIFY_UNPRIV;
1076 }
1077
1078#ifdef CONFIG_AUDITSYSCALL
1079 if (flags & ~(FANOTIFY_INIT_FLAGS | FAN_ENABLE_AUDIT))
1080#else
1081 if (flags & ~FANOTIFY_INIT_FLAGS)
1082#endif
1083 return -EINVAL;
1084
1085 if (event_f_flags & ~FANOTIFY_INIT_ALL_EVENT_F_BITS)
1086 return -EINVAL;
1087
1088 switch (event_f_flags & O_ACCMODE) {
1089 case O_RDONLY:
1090 case O_RDWR:
1091 case O_WRONLY:
1092 break;
1093 default:
1094 return -EINVAL;
1095 }
1096
1097 if (fid_mode && class != FAN_CLASS_NOTIF)
1098 return -EINVAL;
1099
1100
1101
1102
1103
1104 if ((fid_mode & FAN_REPORT_NAME) && !(fid_mode & FAN_REPORT_DIR_FID))
1105 return -EINVAL;
1106
1107 f_flags = O_RDWR | FMODE_NONOTIFY;
1108 if (flags & FAN_CLOEXEC)
1109 f_flags |= O_CLOEXEC;
1110 if (flags & FAN_NONBLOCK)
1111 f_flags |= O_NONBLOCK;
1112
1113
1114 group = fsnotify_alloc_user_group(&fanotify_fsnotify_ops);
1115 if (IS_ERR(group)) {
1116 return PTR_ERR(group);
1117 }
1118
1119
1120 group->fanotify_data.ucounts = inc_ucount(current_user_ns(),
1121 current_euid(),
1122 UCOUNT_FANOTIFY_GROUPS);
1123 if (!group->fanotify_data.ucounts) {
1124 fd = -EMFILE;
1125 goto out_destroy_group;
1126 }
1127
1128 group->fanotify_data.flags = flags | internal_flags;
1129 group->memcg = get_mem_cgroup_from_mm(current->mm);
1130
1131 group->fanotify_data.merge_hash = fanotify_alloc_merge_hash();
1132 if (!group->fanotify_data.merge_hash) {
1133 fd = -ENOMEM;
1134 goto out_destroy_group;
1135 }
1136
1137 group->overflow_event = fanotify_alloc_overflow_event();
1138 if (unlikely(!group->overflow_event)) {
1139 fd = -ENOMEM;
1140 goto out_destroy_group;
1141 }
1142
1143 if (force_o_largefile())
1144 event_f_flags |= O_LARGEFILE;
1145 group->fanotify_data.f_flags = event_f_flags;
1146 init_waitqueue_head(&group->fanotify_data.access_waitq);
1147 INIT_LIST_HEAD(&group->fanotify_data.access_list);
1148 switch (class) {
1149 case FAN_CLASS_NOTIF:
1150 group->priority = FS_PRIO_0;
1151 break;
1152 case FAN_CLASS_CONTENT:
1153 group->priority = FS_PRIO_1;
1154 break;
1155 case FAN_CLASS_PRE_CONTENT:
1156 group->priority = FS_PRIO_2;
1157 break;
1158 default:
1159 fd = -EINVAL;
1160 goto out_destroy_group;
1161 }
1162
1163 if (flags & FAN_UNLIMITED_QUEUE) {
1164 fd = -EPERM;
1165 if (!capable(CAP_SYS_ADMIN))
1166 goto out_destroy_group;
1167 group->max_events = UINT_MAX;
1168 } else {
1169 group->max_events = fanotify_max_queued_events;
1170 }
1171
1172 if (flags & FAN_UNLIMITED_MARKS) {
1173 fd = -EPERM;
1174 if (!capable(CAP_SYS_ADMIN))
1175 goto out_destroy_group;
1176 }
1177
1178 if (flags & FAN_ENABLE_AUDIT) {
1179 fd = -EPERM;
1180 if (!capable(CAP_AUDIT_WRITE))
1181 goto out_destroy_group;
1182 }
1183
1184 fd = anon_inode_getfd("[fanotify]", &fanotify_fops, group, f_flags);
1185 if (fd < 0)
1186 goto out_destroy_group;
1187
1188 return fd;
1189
1190out_destroy_group:
1191 fsnotify_destroy_group(group);
1192 return fd;
1193}
1194
1195
1196static int fanotify_test_fid(struct path *path, __kernel_fsid_t *fsid)
1197{
1198 __kernel_fsid_t root_fsid;
1199 int err;
1200
1201
1202
1203
1204 err = vfs_get_fsid(path->dentry, fsid);
1205 if (err)
1206 return err;
1207
1208 if (!fsid->val[0] && !fsid->val[1])
1209 return -ENODEV;
1210
1211
1212
1213
1214
1215 err = vfs_get_fsid(path->dentry->d_sb->s_root, &root_fsid);
1216 if (err)
1217 return err;
1218
1219 if (root_fsid.val[0] != fsid->val[0] ||
1220 root_fsid.val[1] != fsid->val[1])
1221 return -EXDEV;
1222
1223
1224
1225
1226
1227
1228
1229
1230 if (!path->dentry->d_sb->s_export_op ||
1231 !path->dentry->d_sb->s_export_op->fh_to_dentry)
1232 return -EOPNOTSUPP;
1233
1234 return 0;
1235}
1236
1237static int fanotify_events_supported(struct path *path, __u64 mask)
1238{
1239
1240
1241
1242
1243
1244
1245
1246
1247 if (mask & FANOTIFY_PERM_EVENTS &&
1248 path->mnt->mnt_sb->s_type->fs_flags & FS_DISALLOW_NOTIFY_PERM)
1249 return -EINVAL;
1250 return 0;
1251}
1252
1253static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
1254 int dfd, const char __user *pathname)
1255{
1256 struct inode *inode = NULL;
1257 struct vfsmount *mnt = NULL;
1258 struct fsnotify_group *group;
1259 struct fd f;
1260 struct path path;
1261 __kernel_fsid_t __fsid, *fsid = NULL;
1262 u32 valid_mask = FANOTIFY_EVENTS | FANOTIFY_EVENT_FLAGS;
1263 unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS;
1264 bool ignored = flags & FAN_MARK_IGNORED_MASK;
1265 unsigned int obj_type, fid_mode;
1266 u32 umask = 0;
1267 int ret;
1268
1269 pr_debug("%s: fanotify_fd=%d flags=%x dfd=%d pathname=%p mask=%llx\n",
1270 __func__, fanotify_fd, flags, dfd, pathname, mask);
1271
1272
1273 if (upper_32_bits(mask))
1274 return -EINVAL;
1275
1276 if (flags & ~FANOTIFY_MARK_FLAGS)
1277 return -EINVAL;
1278
1279 switch (mark_type) {
1280 case FAN_MARK_INODE:
1281 obj_type = FSNOTIFY_OBJ_TYPE_INODE;
1282 break;
1283 case FAN_MARK_MOUNT:
1284 obj_type = FSNOTIFY_OBJ_TYPE_VFSMOUNT;
1285 break;
1286 case FAN_MARK_FILESYSTEM:
1287 obj_type = FSNOTIFY_OBJ_TYPE_SB;
1288 break;
1289 default:
1290 return -EINVAL;
1291 }
1292
1293 switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) {
1294 case FAN_MARK_ADD:
1295 case FAN_MARK_REMOVE:
1296 if (!mask)
1297 return -EINVAL;
1298 break;
1299 case FAN_MARK_FLUSH:
1300 if (flags & ~(FANOTIFY_MARK_TYPE_BITS | FAN_MARK_FLUSH))
1301 return -EINVAL;
1302 break;
1303 default:
1304 return -EINVAL;
1305 }
1306
1307 if (IS_ENABLED(CONFIG_FANOTIFY_ACCESS_PERMISSIONS))
1308 valid_mask |= FANOTIFY_PERM_EVENTS;
1309
1310 if (mask & ~valid_mask)
1311 return -EINVAL;
1312
1313
1314 if (ignored)
1315 mask &= ~FANOTIFY_EVENT_FLAGS;
1316
1317 f = fdget(fanotify_fd);
1318 if (unlikely(!f.file))
1319 return -EBADF;
1320
1321
1322 ret = -EINVAL;
1323 if (unlikely(f.file->f_op != &fanotify_fops))
1324 goto fput_and_out;
1325 group = f.file->private_data;
1326
1327
1328
1329
1330
1331
1332 ret = -EPERM;
1333 if ((!capable(CAP_SYS_ADMIN) ||
1334 FAN_GROUP_FLAG(group, FANOTIFY_UNPRIV)) &&
1335 mark_type != FAN_MARK_INODE)
1336 goto fput_and_out;
1337
1338
1339
1340
1341
1342 ret = -EINVAL;
1343 if (mask & FANOTIFY_PERM_EVENTS &&
1344 group->priority == FS_PRIO_0)
1345 goto fput_and_out;
1346
1347
1348
1349
1350
1351
1352
1353
1354 fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
1355 if (mask & FANOTIFY_INODE_EVENTS &&
1356 (!fid_mode || mark_type == FAN_MARK_MOUNT))
1357 goto fput_and_out;
1358
1359 if (flags & FAN_MARK_FLUSH) {
1360 ret = 0;
1361 if (mark_type == FAN_MARK_MOUNT)
1362 fsnotify_clear_vfsmount_marks_by_group(group);
1363 else if (mark_type == FAN_MARK_FILESYSTEM)
1364 fsnotify_clear_sb_marks_by_group(group);
1365 else
1366 fsnotify_clear_inode_marks_by_group(group);
1367 goto fput_and_out;
1368 }
1369
1370 ret = fanotify_find_path(dfd, pathname, &path, flags,
1371 (mask & ALL_FSNOTIFY_EVENTS), obj_type);
1372 if (ret)
1373 goto fput_and_out;
1374
1375 if (flags & FAN_MARK_ADD) {
1376 ret = fanotify_events_supported(&path, mask);
1377 if (ret)
1378 goto path_put_and_out;
1379 }
1380
1381 if (fid_mode) {
1382 ret = fanotify_test_fid(&path, &__fsid);
1383 if (ret)
1384 goto path_put_and_out;
1385
1386 fsid = &__fsid;
1387 }
1388
1389
1390 if (mark_type == FAN_MARK_INODE)
1391 inode = path.dentry->d_inode;
1392 else
1393 mnt = path.mnt;
1394
1395
1396 if (mnt || !S_ISDIR(inode->i_mode)) {
1397 mask &= ~FAN_EVENT_ON_CHILD;
1398 umask = FAN_EVENT_ON_CHILD;
1399
1400
1401
1402
1403 if ((fid_mode & FAN_REPORT_DIR_FID) &&
1404 (flags & FAN_MARK_ADD) && !ignored)
1405 mask |= FAN_EVENT_ON_CHILD;
1406 }
1407
1408
1409 switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE)) {
1410 case FAN_MARK_ADD:
1411 if (mark_type == FAN_MARK_MOUNT)
1412 ret = fanotify_add_vfsmount_mark(group, mnt, mask,
1413 flags, fsid);
1414 else if (mark_type == FAN_MARK_FILESYSTEM)
1415 ret = fanotify_add_sb_mark(group, mnt->mnt_sb, mask,
1416 flags, fsid);
1417 else
1418 ret = fanotify_add_inode_mark(group, inode, mask,
1419 flags, fsid);
1420 break;
1421 case FAN_MARK_REMOVE:
1422 if (mark_type == FAN_MARK_MOUNT)
1423 ret = fanotify_remove_vfsmount_mark(group, mnt, mask,
1424 flags, umask);
1425 else if (mark_type == FAN_MARK_FILESYSTEM)
1426 ret = fanotify_remove_sb_mark(group, mnt->mnt_sb, mask,
1427 flags, umask);
1428 else
1429 ret = fanotify_remove_inode_mark(group, inode, mask,
1430 flags, umask);
1431 break;
1432 default:
1433 ret = -EINVAL;
1434 }
1435
1436path_put_and_out:
1437 path_put(&path);
1438fput_and_out:
1439 fdput(f);
1440 return ret;
1441}
1442
1443#ifndef CONFIG_ARCH_SPLIT_ARG64
1444SYSCALL_DEFINE5(fanotify_mark, int, fanotify_fd, unsigned int, flags,
1445 __u64, mask, int, dfd,
1446 const char __user *, pathname)
1447{
1448 return do_fanotify_mark(fanotify_fd, flags, mask, dfd, pathname);
1449}
1450#endif
1451
1452#if defined(CONFIG_ARCH_SPLIT_ARG64) || defined(CONFIG_COMPAT)
1453SYSCALL32_DEFINE6(fanotify_mark,
1454 int, fanotify_fd, unsigned int, flags,
1455 SC_ARG64(mask), int, dfd,
1456 const char __user *, pathname)
1457{
1458 return do_fanotify_mark(fanotify_fd, flags, SC_VAL64(__u64, mask),
1459 dfd, pathname);
1460}
1461#endif
1462
1463
1464
1465
1466
1467
1468static int __init fanotify_user_setup(void)
1469{
1470 struct sysinfo si;
1471 int max_marks;
1472
1473 si_meminfo(&si);
1474
1475
1476
1477
1478
1479
1480 max_marks = (((si.totalram - si.totalhigh) / 100) << PAGE_SHIFT) /
1481 INODE_MARK_COST;
1482 max_marks = clamp(max_marks, FANOTIFY_OLD_DEFAULT_MAX_MARKS,
1483 FANOTIFY_DEFAULT_MAX_USER_MARKS);
1484
1485 BUILD_BUG_ON(FANOTIFY_INIT_FLAGS & FANOTIFY_INTERNAL_GROUP_FLAGS);
1486 BUILD_BUG_ON(HWEIGHT32(FANOTIFY_INIT_FLAGS) != 10);
1487 BUILD_BUG_ON(HWEIGHT32(FANOTIFY_MARK_FLAGS) != 9);
1488
1489 fanotify_mark_cache = KMEM_CACHE(fsnotify_mark,
1490 SLAB_PANIC|SLAB_ACCOUNT);
1491 fanotify_fid_event_cachep = KMEM_CACHE(fanotify_fid_event,
1492 SLAB_PANIC);
1493 fanotify_path_event_cachep = KMEM_CACHE(fanotify_path_event,
1494 SLAB_PANIC);
1495 if (IS_ENABLED(CONFIG_FANOTIFY_ACCESS_PERMISSIONS)) {
1496 fanotify_perm_event_cachep =
1497 KMEM_CACHE(fanotify_perm_event, SLAB_PANIC);
1498 }
1499
1500 fanotify_max_queued_events = FANOTIFY_DEFAULT_MAX_EVENTS;
1501 init_user_ns.ucount_max[UCOUNT_FANOTIFY_GROUPS] =
1502 FANOTIFY_DEFAULT_MAX_GROUPS;
1503 init_user_ns.ucount_max[UCOUNT_FANOTIFY_MARKS] = max_marks;
1504
1505 return 0;
1506}
1507device_initcall(fanotify_user_setup);
1508