fs/notify/fanotify/fanotify_user.c

   1 #include <linux/fanotify.h>
   2 #include <linux/fcntl.h>
   3 #include <linux/file.h>
   4 #include <linux/fs.h>
   5 #include <linux/anon_inodes.h>
   6 #include <linux/fsnotify_backend.h>
   7 #include <linux/init.h>
   8 #include <linux/mount.h>
   9 #include <linux/namei.h>
  10 #include <linux/poll.h>
  11 #include <linux/security.h>
  12 #include <linux/syscalls.h>
  13 #include <linux/slab.h>
  14 #include <linux/types.h>
  15 #include <linux/uaccess.h>
  16
  17 #include <asm/ioctls.h>
  18
  19 extern const struct fsnotify_ops fanotify_fsnotify_ops;
  20
  21 static struct kmem_cache *fanotify_mark_cache __read_mostly;
  22 static struct kmem_cache *fanotify_response_event_cache __read_mostly;
  23
  24 struct fanotify_response_event {
  25         struct list_head list;
  26         __s32 fd;
  27         struct fsnotify_event *event;
  28 };
  29
  30 /*
  31  * Get an fsnotify notification event if one exists and is small
  32  * enough to fit in "count". Return an error pointer if the count
  33  * is not large enough.
  34  *
  35  * Called with the group->notification_mutex held.
  36  */
  37 static struct fsnotify_event *get_one_event(struct fsnotify_group *group,
  38                                             size_t count)
  39 {
  40         BUG_ON(!mutex_is_locked(&group->notification_mutex));
  41
  42         pr_debug("%s: group=%p count=%zd\n", __func__, group, count);
  43
  44         if (fsnotify_notify_queue_is_empty(group))
  45                 return NULL;
  46
  47         if (FAN_EVENT_METADATA_LEN > count)
  48                 return ERR_PTR(-EINVAL);
  49
  50         /* held the notification_mutex the whole time, so this is the
  51          * same event we peeked above */
  52         return fsnotify_remove_notify_event(group);
  53 }
  54
  55 static int create_fd(struct fsnotify_group *group, struct fsnotify_event *event)
  56 {
  57         int client_fd;
  58         struct dentry *dentry;
  59         struct vfsmount *mnt;
  60         struct file *new_file;
  61
  62         pr_debug("%s: group=%p event=%p\n", __func__, group, event);
  63
  64         client_fd = get_unused_fd();
  65         if (client_fd < 0)
  66                 return client_fd;
  67
  68         if (event->data_type != FSNOTIFY_EVENT_PATH) {
  69                 WARN_ON(1);
  70                 put_unused_fd(client_fd);
  71                 return -EINVAL;
  72         }
  73
  74         /*
  75          * we need a new file handle for the userspace program so it can read even if it was
  76          * originally opened O_WRONLY.
  77          */
  78         dentry = dget(event->path.dentry);
  79         mnt = mntget(event->path.mnt);
  80         /* it's possible this event was an overflow event.  in that case dentry and mnt
  81          * are NULL;  That's fine, just don't call dentry open */
  82         if (dentry && mnt)
  83                 new_file = dentry_open(dentry, mnt,
  84                                        group->fanotify_data.f_flags | FMODE_NONOTIFY,
  85                                        current_cred());
  86         else
  87                 new_file = ERR_PTR(-EOVERFLOW);
  88         if (IS_ERR(new_file)) {
  89                 /*
  90                  * we still send an event even if we can't open the file.  this
  91                  * can happen when say tasks are gone and we try to open their
  92                  * /proc files or we try to open a WRONLY file like in sysfs
  93                  * we just send the errno to userspace since there isn't much
  94                  * else we can do.
  95                  */
  96                 put_unused_fd(client_fd);
  97                 client_fd = PTR_ERR(new_file);
  98         } else {
  99                 fd_install(client_fd, new_file);
 100         }
 101
 102         return client_fd;
 103 }
 104
 105 static ssize_t fill_event_metadata(struct fsnotify_group *group,
 106                                    struct fanotify_event_metadata *metadata,
 107                                    struct fsnotify_event *event)
 108 {
 109         pr_debug("%s: group=%p metadata=%p event=%p\n", __func__,
 110                  group, metadata, event);
 111
 112         metadata->event_len = FAN_EVENT_METADATA_LEN;
 113         metadata->vers = FANOTIFY_METADATA_VERSION;
 114         metadata->mask = event->mask & FAN_ALL_OUTGOING_EVENTS;
 115         metadata->pid = pid_vnr(event->tgid);
 116         metadata->fd = create_fd(group, event);
 117
 118         return metadata->fd;
 119 }
 120
 121 #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
 122 static struct fanotify_response_event *dequeue_re(struct fsnotify_group *group,
 123                                                   __s32 fd)
 124 {
 125         struct fanotify_response_event *re, *return_re = NULL;
 126
 127         mutex_lock(&group->fanotify_data.access_mutex);
 128         list_for_each_entry(re, &group->fanotify_data.access_list, list) {
 129                 if (re->fd != fd)
 130                         continue;
 131
 132                 list_del_init(&re->list);
 133                 return_re = re;
 134                 break;
 135         }
 136         mutex_unlock(&group->fanotify_data.access_mutex);
 137
 138         pr_debug("%s: found return_re=%p\n", __func__, return_re);
 139
 140         return return_re;
 141 }
 142
 143 static int process_access_response(struct fsnotify_group *group,
 144                                    struct fanotify_response *response_struct)
 145 {
 146         struct fanotify_response_event *re;
 147         __s32 fd = response_struct->fd;
 148         __u32 response = response_struct->response;
 149
 150         pr_debug("%s: group=%p fd=%d response=%d\n", __func__, group,
 151                  fd, response);
 152         /*
 153          * make sure the response is valid, if invalid we do nothing and either
 154          * userspace can send a valid responce or we will clean it up after the
 155          * timeout
 156          */
 157         switch (response) {
 158         case FAN_ALLOW:
 159         case FAN_DENY:
 160                 break;
 161         default:
 162                 return -EINVAL;
 163         }
 164
 165         if (fd < 0)
 166                 return -EINVAL;
 167
 168         re = dequeue_re(group, fd);
 169         if (!re)
 170                 return -ENOENT;
 171
 172         re->event->response = response;
 173
 174         wake_up(&group->fanotify_data.access_waitq);
 175
 176         kmem_cache_free(fanotify_response_event_cache, re);
 177
 178         return 0;
 179 }
 180
 181 static int prepare_for_access_response(struct fsnotify_group *group,
 182                                        struct fsnotify_event *event,
 183                                        __s32 fd)
 184 {
 185         struct fanotify_response_event *re;
 186
 187         if (!(event->mask & FAN_ALL_PERM_EVENTS))
 188                 return 0;
 189
 190         re = kmem_cache_alloc(fanotify_response_event_cache, GFP_KERNEL);
 191         if (!re)
 192                 return -ENOMEM;
 193
 194         re->event = event;
 195         re->fd = fd;
 196
 197         mutex_lock(&group->fanotify_data.access_mutex);
 198
 199         if (group->fanotify_data.bypass_perm) {
 200                 mutex_unlock(&group->fanotify_data.access_mutex);
 201                 kmem_cache_free(fanotify_response_event_cache, re);
 202                 event->response = FAN_ALLOW;
 203                 return 0;
 204         }
 205
 206         list_add_tail(&re->list, &group->fanotify_data.access_list);
 207         mutex_unlock(&group->fanotify_data.access_mutex);
 208
 209         return 0;
 210 }
 211
 212 static void remove_access_response(struct fsnotify_group *group,
 213                                    struct fsnotify_event *event,
 214                                    __s32 fd)
 215 {
 216         struct fanotify_response_event *re;
 217
 218         if (!(event->mask & FAN_ALL_PERM_EVENTS))
 219                 return;
 220
 221         re = dequeue_re(group, fd);
 222         if (!re)
 223                 return;
 224
 225         BUG_ON(re->event != event);
 226
 227         kmem_cache_free(fanotify_response_event_cache, re);
 228
 229         return;
 230 }
 231 #else
 232 static int prepare_for_access_response(struct fsnotify_group *group,
 233                                        struct fsnotify_event *event,
 234                                        __s32 fd)
 235 {
 236         return 0;
 237 }
 238
 239 static void remove_access_response(struct fsnotify_group *group,
 240                                    struct fsnotify_event *event,
 241                                    __s32 fd)
 242 {
 243         return;
 244 }
 245 #endif
 246
 247 static ssize_t copy_event_to_user(struct fsnotify_group *group,
 248                                   struct fsnotify_event *event,
 249                                   char __user *buf)
 250 {
 251         struct fanotify_event_metadata fanotify_event_metadata;
 252         int fd, ret;
 253
 254         pr_debug("%s: group=%p event=%p\n", __func__, group, event);
 255
 256         fd = fill_event_metadata(group, &fanotify_event_metadata, event);
 257         if (fd < 0)
 258                 return fd;
 259
 260         ret = prepare_for_access_response(group, event, fd);
 261         if (ret)
 262                 goto out_close_fd;
 263
 264         ret = -EFAULT;
 265         if (copy_to_user(buf, &fanotify_event_metadata, FAN_EVENT_METADATA_LEN))
 266                 goto out_kill_access_response;
 267
 268         return FAN_EVENT_METADATA_LEN;
 269
 270 out_kill_access_response:
 271         remove_access_response(group, event, fd);
 272 out_close_fd:
 273         sys_close(fd);
 274         return ret;
 275 }
 276
 277 /* intofiy userspace file descriptor functions */
 278 static unsigned int fanotify_poll(struct file *file, poll_table *wait)
 279 {
 280         struct fsnotify_group *group = file->private_data;
 281         int ret = 0;
 282
 283         poll_wait(file, &group->notification_waitq, wait);
 284         mutex_lock(&group->notification_mutex);
 285         if (!fsnotify_notify_queue_is_empty(group))
 286                 ret = POLLIN | POLLRDNORM;
 287         mutex_unlock(&group->notification_mutex);
 288
 289         return ret;
 290 }
 291
 292 static ssize_t fanotify_read(struct file *file, char __user *buf,
 293                              size_t count, loff_t *pos)
 294 {
 295         struct fsnotify_group *group;
 296         struct fsnotify_event *kevent;
 297         char __user *start;
 298         int ret;
 299         DEFINE_WAIT(wait);
 300
 301         start = buf;
 302         group = file->private_data;
 303
 304         pr_debug("%s: group=%p\n", __func__, group);
 305
 306         while (1) {
 307                 prepare_to_wait(&group->notification_waitq, &wait, TASK_INTERRUPTIBLE);
 308
 309                 mutex_lock(&group->notification_mutex);
 310                 kevent = get_one_event(group, count);
 311                 mutex_unlock(&group->notification_mutex);
 312
 313                 if (kevent) {
 314                         ret = PTR_ERR(kevent);
 315                         if (IS_ERR(kevent))
 316                                 break;
 317                         ret = copy_event_to_user(group, kevent, buf);
 318                         fsnotify_put_event(kevent);
 319                         if (ret < 0)
 320                                 break;
 321                         buf += ret;
 322                         count -= ret;
 323                         continue;
 324                 }
 325
 326                 ret = -EAGAIN;
 327                 if (file->f_flags & O_NONBLOCK)
 328                         break;
 329                 ret = -EINTR;
 330                 if (signal_pending(current))
 331                         break;
 332
 333                 if (start != buf)
 334                         break;
 335
 336                 schedule();
 337         }
 338
 339         finish_wait(&group->notification_waitq, &wait);
 340         if (start != buf && ret != -EFAULT)
 341                 ret = buf - start;
 342         return ret;
 343 }
 344
 345 static ssize_t fanotify_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)
 346 {
 347 #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
 348         struct fanotify_response response = { .fd = -1, .response = -1 };
 349         struct fsnotify_group *group;
 350         int ret;
 351
 352         group = file->private_data;
 353
 354         if (count > sizeof(response))
 355                 count = sizeof(response);
 356
 357         pr_debug("%s: group=%p count=%zu\n", __func__, group, count);
 358
 359         if (copy_from_user(&response, buf, count))
 360                 return -EFAULT;
 361
 362         ret = process_access_response(group, &response);
 363         if (ret < 0)
 364                 count = ret;
 365
 366         return count;
 367 #else
 368         return -EINVAL;
 369 #endif
 370 }
 371
 372 static int fanotify_release(struct inode *ignored, struct file *file)
 373 {
 374         struct fsnotify_group *group = file->private_data;
 375         struct fanotify_response_event *re, *lre;
 376
 377         pr_debug("%s: file=%p group=%p\n", __func__, file, group);
 378
 379 #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
 380         mutex_lock(&group->fanotify_data.access_mutex);
 381
 382         group->fanotify_data.bypass_perm = true;
 383
 384         list_for_each_entry_safe(re, lre, &group->fanotify_data.access_list, list) {
 385                 pr_debug("%s: found group=%p re=%p event=%p\n", __func__, group,
 386                          re, re->event);
 387
 388                 list_del_init(&re->list);
 389                 re->event->response = FAN_ALLOW;
 390
 391                 kmem_cache_free(fanotify_response_event_cache, re);
 392         }
 393         mutex_unlock(&group->fanotify_data.access_mutex);
 394
 395         wake_up(&group->fanotify_data.access_waitq);
 396 #endif
 397         /* matches the fanotify_init->fsnotify_alloc_group */
 398         fsnotify_put_group(group);
 399
 400         return 0;
 401 }
 402
 403 static long fanotify_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 404 {
 405         struct fsnotify_group *group;
 406         struct fsnotify_event_holder *holder;
 407         void __user *p;
 408         int ret = -ENOTTY;
 409         size_t send_len = 0;
 410
 411         group = file->private_data;
 412
 413         p = (void __user *) arg;
 414
 415         switch (cmd) {
 416         case FIONREAD:
 417                 mutex_lock(&group->notification_mutex);
 418                 list_for_each_entry(holder, &group->notification_list, event_list)
 419                         send_len += FAN_EVENT_METADATA_LEN;
 420                 mutex_unlock(&group->notification_mutex);
 421                 ret = put_user(send_len, (int __user *) p);
 422                 break;
 423         }
 424
 425         return ret;
 426 }
 427
 428 static const struct file_operations fanotify_fops = {
 429         .poll           = fanotify_poll,
 430         .read           = fanotify_read,
 431         .write          = fanotify_write,
 432         .fasync         = NULL,
 433         .release        = fanotify_release,
 434         .unlocked_ioctl = fanotify_ioctl,
 435         .compat_ioctl   = fanotify_ioctl,
 436 };
 437
 438 static void fanotify_free_mark(struct fsnotify_mark *fsn_mark)
 439 {
 440         kmem_cache_free(fanotify_mark_cache, fsn_mark);
 441 }
 442
 443 static int fanotify_find_path(int dfd, const char __user *filename,
 444                               struct path *path, unsigned int flags)
 445 {
 446         int ret;
 447
 448         pr_debug("%s: dfd=%d filename=%p flags=%x\n", __func__,
 449                  dfd, filename, flags);
 450
 451         if (filename == NULL) {
 452                 struct file *file;
 453                 int fput_needed;
 454
 455                 ret = -EBADF;
 456                 file = fget_light(dfd, &fput_needed);
 457                 if (!file)
 458                         goto out;
 459
 460                 ret = -ENOTDIR;
 461                 if ((flags & FAN_MARK_ONLYDIR) &&
 462                     !(S_ISDIR(file->f_path.dentry->d_inode->i_mode))) {
 463                         fput_light(file, fput_needed);
 464                         goto out;
 465                 }
 466
 467                 *path = file->f_path;
 468                 path_get(path);
 469                 fput_light(file, fput_needed);
 470         } else {
 471                 unsigned int lookup_flags = 0;
 472
 473                 if (!(flags & FAN_MARK_DONT_FOLLOW))
 474                         lookup_flags |= LOOKUP_FOLLOW;
 475                 if (flags & FAN_MARK_ONLYDIR)
 476                         lookup_flags |= LOOKUP_DIRECTORY;
 477
 478                 ret = user_path_at(dfd, filename, lookup_flags, path);
 479                 if (ret)
 480                         goto out;
 481         }
 482
 483         /* you can only watch an inode if you have read permissions on it */
 484         ret = inode_permission(path->dentry->d_inode, MAY_READ);
 485         if (ret)
 486                 path_put(path);
 487 out:
 488         return ret;
 489 }
 490
 491 static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark,
 492                                             __u32 mask,
 493                                             unsigned int flags)
 494 {
 495         __u32 oldmask;
 496
 497         spin_lock(&fsn_mark->lock);
 498         if (!(flags & FAN_MARK_IGNORED_MASK)) {
 499                 oldmask = fsn_mark->mask;
 500                 fsnotify_set_mark_mask_locked(fsn_mark, (oldmask & ~mask));
 501         } else {
 502                 oldmask = fsn_mark->ignored_mask;
 503                 fsnotify_set_mark_ignored_mask_locked(fsn_mark, (oldmask & ~mask));
 504         }
 505         spin_unlock(&fsn_mark->lock);
 506
 507         if (!(oldmask & ~mask))
 508                 fsnotify_destroy_mark(fsn_mark);
 509
 510         return mask & oldmask;
 511 }
 512
 513 static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group,
 514                                          struct vfsmount *mnt, __u32 mask,
 515                                          unsigned int flags)
 516 {
 517         struct fsnotify_mark *fsn_mark = NULL;
 518         __u32 removed;
 519
 520         fsn_mark = fsnotify_find_vfsmount_mark(group, mnt);
 521         if (!fsn_mark)
 522                 return -ENOENT;
 523
 524         removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags);
 525         fsnotify_put_mark(fsn_mark);
 526         if (removed & mnt->mnt_fsnotify_mask)
 527                 fsnotify_recalc_vfsmount_mask(mnt);
 528
 529         return 0;
 530 }
 531
 532 static int fanotify_remove_inode_mark(struct fsnotify_group *group,
 533                                       struct inode *inode, __u32 mask,
 534                                       unsigned int flags)
 535 {
 536         struct fsnotify_mark *fsn_mark = NULL;
 537         __u32 removed;
 538
 539         fsn_mark = fsnotify_find_inode_mark(group, inode);
 540         if (!fsn_mark)
 541                 return -ENOENT;
 542
 543         removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags);
 544         /* matches the fsnotify_find_inode_mark() */
 545         fsnotify_put_mark(fsn_mark);
 546         if (removed & inode->i_fsnotify_mask)
 547                 fsnotify_recalc_inode_mask(inode);
 548
 549         return 0;
 550 }
 551
 552 static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark,
 553                                        __u32 mask,
 554                                        unsigned int flags)
 555 {
 556         __u32 oldmask;
 557
 558         spin_lock(&fsn_mark->lock);
 559         if (!(flags & FAN_MARK_IGNORED_MASK)) {
 560                 oldmask = fsn_mark->mask;
 561                 fsnotify_set_mark_mask_locked(fsn_mark, (oldmask | mask));
 562         } else {
 563                 oldmask = fsn_mark->ignored_mask;
 564                 fsnotify_set_mark_ignored_mask_locked(fsn_mark, (oldmask | mask));
 565                 if (flags & FAN_MARK_IGNORED_SURV_MODIFY)
 566                         fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY;
 567         }
 568         spin_unlock(&fsn_mark->lock);
 569
 570         return mask & ~oldmask;
 571 }
 572
 573 static int fanotify_add_vfsmount_mark(struct fsnotify_group *group,
 574                                       struct vfsmount *mnt, __u32 mask,
 575                                       unsigned int flags)
 576 {
 577         struct fsnotify_mark *fsn_mark;
 578         __u32 added;
 579
 580         fsn_mark = fsnotify_find_vfsmount_mark(group, mnt);
 581         if (!fsn_mark) {
 582                 int ret;
 583
 584                 fsn_mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL);
 585                 if (!fsn_mark)
 586                         return -ENOMEM;
 587
 588                 fsnotify_init_mark(fsn_mark, fanotify_free_mark);
 589                 ret = fsnotify_add_mark(fsn_mark, group, NULL, mnt, 0);
 590                 if (ret) {
 591                         fanotify_free_mark(fsn_mark);
 592                         return ret;
 593                 }
 594         }
 595         added = fanotify_mark_add_to_mask(fsn_mark, mask, flags);
 596         fsnotify_put_mark(fsn_mark);
 597         if (added & ~mnt->mnt_fsnotify_mask)
 598                 fsnotify_recalc_vfsmount_mask(mnt);
 599
 600         return 0;
 601 }
 602
 603 static int fanotify_add_inode_mark(struct fsnotify_group *group,
 604                                    struct inode *inode, __u32 mask,
 605                                    unsigned int flags)
 606 {
 607         struct fsnotify_mark *fsn_mark;
 608         __u32 added;
 609
 610         pr_debug("%s: group=%p inode=%p\n", __func__, group, inode);
 611
 612         fsn_mark = fsnotify_find_inode_mark(group, inode);
 613         if (!fsn_mark) {
 614                 int ret;
 615
 616                 fsn_mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL);
 617                 if (!fsn_mark)
 618                         return -ENOMEM;
 619
 620                 fsnotify_init_mark(fsn_mark, fanotify_free_mark);
 621                 ret = fsnotify_add_mark(fsn_mark, group, inode, NULL, 0);
 622                 if (ret) {
 623                         fanotify_free_mark(fsn_mark);
 624                         return ret;
 625                 }
 626         }
 627         added = fanotify_mark_add_to_mask(fsn_mark, mask, flags);
 628         fsnotify_put_mark(fsn_mark);
 629         if (added & ~inode->i_fsnotify_mask)
 630                 fsnotify_recalc_inode_mask(inode);
 631         return 0;
 632 }
 633
 634 /* fanotify syscalls */
 635 SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
 636 {
 637         struct fsnotify_group *group;
 638         int f_flags, fd;
 639
 640         pr_debug("%s: flags=%d event_f_flags=%d\n",
 641                 __func__, flags, event_f_flags);
 642
 643         if (!capable(CAP_SYS_ADMIN))
 644                 return -EACCES;
 645
 646         if (flags & ~FAN_ALL_INIT_FLAGS)
 647                 return -EINVAL;
 648
 649         f_flags = O_RDWR | FMODE_NONOTIFY;
 650         if (flags & FAN_CLOEXEC)
 651                 f_flags |= O_CLOEXEC;
 652         if (flags & FAN_NONBLOCK)
 653                 f_flags |= O_NONBLOCK;
 654
 655         /* fsnotify_alloc_group takes a ref.  Dropped in fanotify_release */
 656         group = fsnotify_alloc_group(&fanotify_fsnotify_ops);
 657         if (IS_ERR(group))
 658                 return PTR_ERR(group);
 659
 660         group->fanotify_data.f_flags = event_f_flags;
 661 #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
 662         mutex_init(&group->fanotify_data.access_mutex);
 663         init_waitqueue_head(&group->fanotify_data.access_waitq);
 664         INIT_LIST_HEAD(&group->fanotify_data.access_list);
 665 #endif
 666
 667         fd = anon_inode_getfd("[fanotify]", &fanotify_fops, group, f_flags);
 668         if (fd < 0)
 669                 goto out_put_group;
 670
 671         return fd;
 672
 673 out_put_group:
 674         fsnotify_put_group(group);
 675         return fd;
 676 }
 677
 678 SYSCALL_DEFINE(fanotify_mark)(int fanotify_fd, unsigned int flags,
 679                               __u64 mask, int dfd,
 680                               const char  __user * pathname)
 681 {
 682         struct inode *inode = NULL;
 683         struct vfsmount *mnt = NULL;
 684         struct fsnotify_group *group;
 685         struct file *filp;
 686         struct path path;
 687         int ret, fput_needed;
 688
 689         pr_debug("%s: fanotify_fd=%d flags=%x dfd=%d pathname=%p mask=%llx\n",
 690                  __func__, fanotify_fd, flags, dfd, pathname, mask);
 691
 692         /* we only use the lower 32 bits as of right now. */
 693         if (mask & ((__u64)0xffffffff << 32))
 694                 return -EINVAL;
 695
 696         if (flags & ~FAN_ALL_MARK_FLAGS)
 697                 return -EINVAL;
 698         switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) {
 699         case FAN_MARK_ADD:
 700         case FAN_MARK_REMOVE:
 701         case FAN_MARK_FLUSH:
 702                 break;
 703         default:
 704                 return -EINVAL;
 705         }
 706 #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
 707         if (mask & ~(FAN_ALL_EVENTS | FAN_ALL_PERM_EVENTS | FAN_EVENT_ON_CHILD))
 708 #else
 709         if (mask & ~(FAN_ALL_EVENTS | FAN_EVENT_ON_CHILD))
 710 #endif
 711                 return -EINVAL;
 712
 713         filp = fget_light(fanotify_fd, &fput_needed);
 714         if (unlikely(!filp))
 715                 return -EBADF;
 716
 717         /* verify that this is indeed an fanotify instance */
 718         ret = -EINVAL;
 719         if (unlikely(filp->f_op != &fanotify_fops))
 720                 goto fput_and_out;
 721
 722         ret = fanotify_find_path(dfd, pathname, &path, flags);
 723         if (ret)
 724                 goto fput_and_out;
 725
 726         /* inode held in place by reference to path; group by fget on fd */
 727         if (!(flags & FAN_MARK_MOUNT))
 728                 inode = path.dentry->d_inode;
 729         else
 730                 mnt = path.mnt;
 731         group = filp->private_data;
 732
 733         /* create/update an inode mark */
 734         switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) {
 735         case FAN_MARK_ADD:
 736                 if (flags & FAN_MARK_MOUNT)
 737                         ret = fanotify_add_vfsmount_mark(group, mnt, mask, flags);
 738                 else
 739                         ret = fanotify_add_inode_mark(group, inode, mask, flags);
 740                 break;
 741         case FAN_MARK_REMOVE:
 742                 if (flags & FAN_MARK_MOUNT)
 743                         ret = fanotify_remove_vfsmount_mark(group, mnt, mask, flags);
 744                 else
 745                         ret = fanotify_remove_inode_mark(group, inode, mask, flags);
 746                 break;
 747         case FAN_MARK_FLUSH:
 748                 if (flags & FAN_MARK_MOUNT)
 749                         fsnotify_clear_vfsmount_marks_by_group(group);
 750                 else
 751                         fsnotify_clear_inode_marks_by_group(group);
 752                 break;
 753         default:
 754                 ret = -EINVAL;
 755         }
 756
 757         path_put(&path);
 758 fput_and_out:
 759         fput_light(filp, fput_needed);
 760         return ret;
 761 }
 762
 763 #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
 764 asmlinkage long SyS_fanotify_mark(long fanotify_fd, long flags, __u64 mask,
 765                                   long dfd, long pathname)
 766 {
 767         return SYSC_fanotify_mark((int) fanotify_fd, (unsigned int) flags,
 768                                   mask, (int) dfd,
 769                                   (const char  __user *) pathname);
 770 }
 771 SYSCALL_ALIAS(sys_fanotify_mark, SyS_fanotify_mark);
 772 #endif
 773
 774 /*
 775  * fanotify_user_setup - Our initialization function.  Note that we cannnot return
 776  * error because we have compiled-in VFS hooks.  So an (unlikely) failure here
 777  * must result in panic().
 778  */
 779 static int __init fanotify_user_setup(void)
 780 {
 781         fanotify_mark_cache = KMEM_CACHE(fsnotify_mark, SLAB_PANIC);
 782         fanotify_response_event_cache = KMEM_CACHE(fanotify_response_event,
 783                                                    SLAB_PANIC);
 784
 785         return 0;
 786 }
 787 device_initcall(fanotify_user_setup);