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 #include <linux/compat.h> 17 18 #include <asm/ioctls.h> 19 20 #include "../../mount.h" 21 #include "../fdinfo.h" 22 #include "fanotify.h" 23 24 #define FANOTIFY_DEFAULT_MAX_EVENTS 16384 25 #define FANOTIFY_DEFAULT_MAX_MARKS 8192 26 #define FANOTIFY_DEFAULT_MAX_LISTENERS 128 27 28 /* 29 * All flags that may be specified in parameter event_f_flags of fanotify_init. 30 * 31 * Internal and external open flags are stored together in field f_flags of 32 * struct file. Only external open flags shall be allowed in event_f_flags. 33 * Internal flags like FMODE_NONOTIFY, FMODE_EXEC, FMODE_NOCMTIME shall be 34 * excluded. 35 */ 36 #define FANOTIFY_INIT_ALL_EVENT_F_BITS ( \ 37 O_ACCMODE | O_APPEND | O_NONBLOCK | \ 38 __O_SYNC | O_DSYNC | O_CLOEXEC | \ 39 O_LARGEFILE | O_NOATIME ) 40 41 extern const struct fsnotify_ops fanotify_fsnotify_ops; 42 43 static struct kmem_cache *fanotify_mark_cache __read_mostly; 44 struct kmem_cache *fanotify_event_cachep __read_mostly; 45 struct kmem_cache *fanotify_perm_event_cachep __read_mostly; 46 47 /* 48 * Get an fsnotify notification event if one exists and is small 49 * enough to fit in "count". Return an error pointer if the count 50 * is not large enough. 51 * 52 * Called with the group->notification_mutex held. 53 */ 54 static struct fsnotify_event *get_one_event(struct fsnotify_group *group, 55 size_t count) 56 { 57 BUG_ON(!mutex_is_locked(&group->notification_mutex)); 58 59 pr_debug("%s: group=%p count=%zd\n", __func__, group, count); 60 61 if (fsnotify_notify_queue_is_empty(group)) 62 return NULL; 63 64 if (FAN_EVENT_METADATA_LEN > count) 65 return ERR_PTR(-EINVAL); 66 67 /* held the notification_mutex the whole time, so this is the 68 * same event we peeked above */ 69 return fsnotify_remove_notify_event(group); 70 } 71 72 static int create_fd(struct fsnotify_group *group, 73 struct fanotify_event_info *event, 74 struct file **file) 75 { 76 int client_fd; 77 struct file *new_file; 78 79 pr_debug("%s: group=%p event=%p\n", __func__, group, event); 80 81 client_fd = get_unused_fd(); 82 if (client_fd < 0) 83 return client_fd; 84 85 /* 86 * we need a new file handle for the userspace program so it can read even if it was 87 * originally opened O_WRONLY. 88 */ 89 /* it's possible this event was an overflow event. in that case dentry and mnt 90 * are NULL; That's fine, just don't call dentry open */ 91 if (event->path.dentry && event->path.mnt) 92 new_file = dentry_open(&event->path, 93 group->fanotify_data.f_flags | FMODE_NONOTIFY, 94 current_cred()); 95 else 96 new_file = ERR_PTR(-EOVERFLOW); 97 if (IS_ERR(new_file)) { 98 /* 99 * we still send an event even if we can't open the file. this 100 * can happen when say tasks are gone and we try to open their 101 * /proc files or we try to open a WRONLY file like in sysfs 102 * we just send the errno to userspace since there isn't much 103 * else we can do. 104 */ 105 put_unused_fd(client_fd); 106 client_fd = PTR_ERR(new_file); 107 } else { 108 *file = new_file; 109 } 110 111 return client_fd; 112 } 113 114 static int fill_event_metadata(struct fsnotify_group *group, 115 struct fanotify_event_metadata *metadata, 116 struct fsnotify_event *fsn_event, 117 struct file **file) 118 { 119 int ret = 0; 120 struct fanotify_event_info *event; 121 122 pr_debug("%s: group=%p metadata=%p event=%p\n", __func__, 123 group, metadata, fsn_event); 124 125 *file = NULL; 126 event = container_of(fsn_event, struct fanotify_event_info, fse); 127 metadata->event_len = FAN_EVENT_METADATA_LEN; 128 metadata->metadata_len = FAN_EVENT_METADATA_LEN; 129 metadata->vers = FANOTIFY_METADATA_VERSION; 130 metadata->reserved = 0; 131 metadata->mask = fsn_event->mask & FAN_ALL_OUTGOING_EVENTS; 132 metadata->pid = pid_vnr(event->tgid); 133 if (unlikely(fsn_event->mask & FAN_Q_OVERFLOW)) 134 metadata->fd = FAN_NOFD; 135 else { 136 metadata->fd = create_fd(group, event, file); 137 if (metadata->fd < 0) 138 ret = metadata->fd; 139 } 140 141 return ret; 142 } 143 144 #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS 145 static struct fanotify_perm_event_info *dequeue_event( 146 struct fsnotify_group *group, int fd) 147 { 148 struct fanotify_perm_event_info *event, *return_e = NULL; 149 150 spin_lock(&group->fanotify_data.access_lock); 151 list_for_each_entry(event, &group->fanotify_data.access_list, 152 fae.fse.list) { 153 if (event->fd != fd) 154 continue; 155 156 list_del_init(&event->fae.fse.list); 157 return_e = event; 158 break; 159 } 160 spin_unlock(&group->fanotify_data.access_lock); 161 162 pr_debug("%s: found return_re=%p\n", __func__, return_e); 163 164 return return_e; 165 } 166 167 static int process_access_response(struct fsnotify_group *group, 168 struct fanotify_response *response_struct) 169 { 170 struct fanotify_perm_event_info *event; 171 int fd = response_struct->fd; 172 int response = response_struct->response; 173 174 pr_debug("%s: group=%p fd=%d response=%d\n", __func__, group, 175 fd, response); 176 /* 177 * make sure the response is valid, if invalid we do nothing and either 178 * userspace can send a valid response or we will clean it up after the 179 * timeout 180 */ 181 switch (response) { 182 case FAN_ALLOW: 183 case FAN_DENY: 184 break; 185 default: 186 return -EINVAL; 187 } 188 189 if (fd < 0) 190 return -EINVAL; 191 192 event = dequeue_event(group, fd); 193 if (!event) 194 return -ENOENT; 195 196 event->response = response; 197 wake_up(&group->fanotify_data.access_waitq); 198 199 return 0; 200 } 201 #endif 202 203 static ssize_t copy_event_to_user(struct fsnotify_group *group, 204 struct fsnotify_event *event, 205 char __user *buf) 206 { 207 struct fanotify_event_metadata fanotify_event_metadata; 208 struct file *f; 209 int fd, ret; 210 211 pr_debug("%s: group=%p event=%p\n", __func__, group, event); 212 213 ret = fill_event_metadata(group, &fanotify_event_metadata, event, &f); 214 if (ret < 0) 215 return ret; 216 217 fd = fanotify_event_metadata.fd; 218 ret = -EFAULT; 219 if (copy_to_user(buf, &fanotify_event_metadata, 220 fanotify_event_metadata.event_len)) 221 goto out_close_fd; 222 223 #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS 224 if (event->mask & FAN_ALL_PERM_EVENTS) 225 FANOTIFY_PE(event)->fd = fd; 226 #endif 227 228 if (fd != FAN_NOFD) 229 fd_install(fd, f); 230 return fanotify_event_metadata.event_len; 231 232 out_close_fd: 233 if (fd != FAN_NOFD) { 234 put_unused_fd(fd); 235 fput(f); 236 } 237 return ret; 238 } 239 240 /* intofiy userspace file descriptor functions */ 241 static unsigned int fanotify_poll(struct file *file, poll_table *wait) 242 { 243 struct fsnotify_group *group = file->private_data; 244 int ret = 0; 245 246 poll_wait(file, &group->notification_waitq, wait); 247 mutex_lock(&group->notification_mutex); 248 if (!fsnotify_notify_queue_is_empty(group)) 249 ret = POLLIN | POLLRDNORM; 250 mutex_unlock(&group->notification_mutex); 251 252 return ret; 253 } 254 255 static ssize_t fanotify_read(struct file *file, char __user *buf, 256 size_t count, loff_t *pos) 257 { 258 struct fsnotify_group *group; 259 struct fsnotify_event *kevent; 260 char __user *start; 261 int ret; 262 DEFINE_WAIT(wait); 263 264 start = buf; 265 group = file->private_data; 266 267 pr_debug("%s: group=%p\n", __func__, group); 268 269 while (1) { 270 prepare_to_wait(&group->notification_waitq, &wait, TASK_INTERRUPTIBLE); 271 272 mutex_lock(&group->notification_mutex); 273 kevent = get_one_event(group, count); 274 mutex_unlock(&group->notification_mutex); 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 schedule(); 293 continue; 294 } 295 296 ret = copy_event_to_user(group, kevent, buf); 297 /* 298 * Permission events get queued to wait for response. Other 299 * events can be destroyed now. 300 */ 301 if (!(kevent->mask & FAN_ALL_PERM_EVENTS)) { 302 fsnotify_destroy_event(group, kevent); 303 if (ret < 0) 304 break; 305 } else { 306 #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS 307 if (ret < 0) { 308 FANOTIFY_PE(kevent)->response = FAN_DENY; 309 wake_up(&group->fanotify_data.access_waitq); 310 break; 311 } 312 spin_lock(&group->fanotify_data.access_lock); 313 list_add_tail(&kevent->list, 314 &group->fanotify_data.access_list); 315 spin_unlock(&group->fanotify_data.access_lock); 316 #endif 317 } 318 buf += ret; 319 count -= ret; 320 } 321 322 finish_wait(&group->notification_waitq, &wait); 323 if (start != buf && ret != -EFAULT) 324 ret = buf - start; 325 return ret; 326 } 327 328 static ssize_t fanotify_write(struct file *file, const char __user *buf, size_t count, loff_t *pos) 329 { 330 #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS 331 struct fanotify_response response = { .fd = -1, .response = -1 }; 332 struct fsnotify_group *group; 333 int ret; 334 335 group = file->private_data; 336 337 if (count > sizeof(response)) 338 count = sizeof(response); 339 340 pr_debug("%s: group=%p count=%zu\n", __func__, group, count); 341 342 if (copy_from_user(&response, buf, count)) 343 return -EFAULT; 344 345 ret = process_access_response(group, &response); 346 if (ret < 0) 347 count = ret; 348 349 return count; 350 #else 351 return -EINVAL; 352 #endif 353 } 354 355 static int fanotify_release(struct inode *ignored, struct file *file) 356 { 357 struct fsnotify_group *group = file->private_data; 358 359 #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS 360 struct fanotify_perm_event_info *event, *next; 361 362 spin_lock(&group->fanotify_data.access_lock); 363 364 atomic_inc(&group->fanotify_data.bypass_perm); 365 366 list_for_each_entry_safe(event, next, &group->fanotify_data.access_list, 367 fae.fse.list) { 368 pr_debug("%s: found group=%p event=%p\n", __func__, group, 369 event); 370 371 list_del_init(&event->fae.fse.list); 372 event->response = FAN_ALLOW; 373 } 374 spin_unlock(&group->fanotify_data.access_lock); 375 376 wake_up(&group->fanotify_data.access_waitq); 377 #endif 378 379 /* matches the fanotify_init->fsnotify_alloc_group */ 380 fsnotify_destroy_group(group); 381 382 return 0; 383 } 384 385 static long fanotify_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 386 { 387 struct fsnotify_group *group; 388 struct fsnotify_event *fsn_event; 389 void __user *p; 390 int ret = -ENOTTY; 391 size_t send_len = 0; 392 393 group = file->private_data; 394 395 p = (void __user *) arg; 396 397 switch (cmd) { 398 case FIONREAD: 399 mutex_lock(&group->notification_mutex); 400 list_for_each_entry(fsn_event, &group->notification_list, list) 401 send_len += FAN_EVENT_METADATA_LEN; 402 mutex_unlock(&group->notification_mutex); 403 ret = put_user(send_len, (int __user *) p); 404 break; 405 } 406 407 return ret; 408 } 409 410 static const struct file_operations fanotify_fops = { 411 .show_fdinfo = fanotify_show_fdinfo, 412 .poll = fanotify_poll, 413 .read = fanotify_read, 414 .write = fanotify_write, 415 .fasync = NULL, 416 .release = fanotify_release, 417 .unlocked_ioctl = fanotify_ioctl, 418 .compat_ioctl = fanotify_ioctl, 419 .llseek = noop_llseek, 420 }; 421 422 static void fanotify_free_mark(struct fsnotify_mark *fsn_mark) 423 { 424 kmem_cache_free(fanotify_mark_cache, fsn_mark); 425 } 426 427 static int fanotify_find_path(int dfd, const char __user *filename, 428 struct path *path, unsigned int flags) 429 { 430 int ret; 431 432 pr_debug("%s: dfd=%d filename=%p flags=%x\n", __func__, 433 dfd, filename, flags); 434 435 if (filename == NULL) { 436 struct fd f = fdget(dfd); 437 438 ret = -EBADF; 439 if (!f.file) 440 goto out; 441 442 ret = -ENOTDIR; 443 if ((flags & FAN_MARK_ONLYDIR) && 444 !(S_ISDIR(file_inode(f.file)->i_mode))) { 445 fdput(f); 446 goto out; 447 } 448 449 *path = f.file->f_path; 450 path_get(path); 451 fdput(f); 452 } else { 453 unsigned int lookup_flags = 0; 454 455 if (!(flags & FAN_MARK_DONT_FOLLOW)) 456 lookup_flags |= LOOKUP_FOLLOW; 457 if (flags & FAN_MARK_ONLYDIR) 458 lookup_flags |= LOOKUP_DIRECTORY; 459 460 ret = user_path_at(dfd, filename, lookup_flags, path); 461 if (ret) 462 goto out; 463 } 464 465 /* you can only watch an inode if you have read permissions on it */ 466 ret = inode_permission(path->dentry->d_inode, MAY_READ); 467 if (ret) 468 path_put(path); 469 out: 470 return ret; 471 } 472 473 static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark, 474 __u32 mask, 475 unsigned int flags, 476 int *destroy) 477 { 478 __u32 oldmask; 479 480 spin_lock(&fsn_mark->lock); 481 if (!(flags & FAN_MARK_IGNORED_MASK)) { 482 oldmask = fsn_mark->mask; 483 fsnotify_set_mark_mask_locked(fsn_mark, (oldmask & ~mask)); 484 } else { 485 oldmask = fsn_mark->ignored_mask; 486 fsnotify_set_mark_ignored_mask_locked(fsn_mark, (oldmask & ~mask)); 487 } 488 spin_unlock(&fsn_mark->lock); 489 490 *destroy = !(oldmask & ~mask); 491 492 return mask & oldmask; 493 } 494 495 static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group, 496 struct vfsmount *mnt, __u32 mask, 497 unsigned int flags) 498 { 499 struct fsnotify_mark *fsn_mark = NULL; 500 __u32 removed; 501 int destroy_mark; 502 503 mutex_lock(&group->mark_mutex); 504 fsn_mark = fsnotify_find_vfsmount_mark(group, mnt); 505 if (!fsn_mark) { 506 mutex_unlock(&group->mark_mutex); 507 return -ENOENT; 508 } 509 510 removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags, 511 &destroy_mark); 512 if (destroy_mark) 513 fsnotify_destroy_mark_locked(fsn_mark, group); 514 mutex_unlock(&group->mark_mutex); 515 516 fsnotify_put_mark(fsn_mark); 517 if (removed & real_mount(mnt)->mnt_fsnotify_mask) 518 fsnotify_recalc_vfsmount_mask(mnt); 519 520 return 0; 521 } 522 523 static int fanotify_remove_inode_mark(struct fsnotify_group *group, 524 struct inode *inode, __u32 mask, 525 unsigned int flags) 526 { 527 struct fsnotify_mark *fsn_mark = NULL; 528 __u32 removed; 529 int destroy_mark; 530 531 mutex_lock(&group->mark_mutex); 532 fsn_mark = fsnotify_find_inode_mark(group, inode); 533 if (!fsn_mark) { 534 mutex_unlock(&group->mark_mutex); 535 return -ENOENT; 536 } 537 538 removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags, 539 &destroy_mark); 540 if (destroy_mark) 541 fsnotify_destroy_mark_locked(fsn_mark, group); 542 mutex_unlock(&group->mark_mutex); 543 544 /* 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 = -1; 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 __u32 tmask = fsn_mark->ignored_mask | mask; 564 fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask); 565 if (flags & FAN_MARK_IGNORED_SURV_MODIFY) 566 fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY; 567 } 568 569 if (!(flags & FAN_MARK_ONDIR)) { 570 __u32 tmask = fsn_mark->ignored_mask | FAN_ONDIR; 571 fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask); 572 } 573 574 spin_unlock(&fsn_mark->lock); 575 576 return mask & ~oldmask; 577 } 578 579 static struct fsnotify_mark *fanotify_add_new_mark(struct fsnotify_group *group, 580 struct inode *inode, 581 struct vfsmount *mnt) 582 { 583 struct fsnotify_mark *mark; 584 int ret; 585 586 if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks) 587 return ERR_PTR(-ENOSPC); 588 589 mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL); 590 if (!mark) 591 return ERR_PTR(-ENOMEM); 592 593 fsnotify_init_mark(mark, fanotify_free_mark); 594 ret = fsnotify_add_mark_locked(mark, group, inode, mnt, 0); 595 if (ret) { 596 fsnotify_put_mark(mark); 597 return ERR_PTR(ret); 598 } 599 600 return mark; 601 } 602 603 604 static int fanotify_add_vfsmount_mark(struct fsnotify_group *group, 605 struct vfsmount *mnt, __u32 mask, 606 unsigned int flags) 607 { 608 struct fsnotify_mark *fsn_mark; 609 __u32 added; 610 611 mutex_lock(&group->mark_mutex); 612 fsn_mark = fsnotify_find_vfsmount_mark(group, mnt); 613 if (!fsn_mark) { 614 fsn_mark = fanotify_add_new_mark(group, NULL, mnt); 615 if (IS_ERR(fsn_mark)) { 616 mutex_unlock(&group->mark_mutex); 617 return PTR_ERR(fsn_mark); 618 } 619 } 620 added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); 621 mutex_unlock(&group->mark_mutex); 622 623 if (added & ~real_mount(mnt)->mnt_fsnotify_mask) 624 fsnotify_recalc_vfsmount_mask(mnt); 625 626 fsnotify_put_mark(fsn_mark); 627 return 0; 628 } 629 630 static int fanotify_add_inode_mark(struct fsnotify_group *group, 631 struct inode *inode, __u32 mask, 632 unsigned int flags) 633 { 634 struct fsnotify_mark *fsn_mark; 635 __u32 added; 636 637 pr_debug("%s: group=%p inode=%p\n", __func__, group, inode); 638 639 /* 640 * If some other task has this inode open for write we should not add 641 * an ignored mark, unless that ignored mark is supposed to survive 642 * modification changes anyway. 643 */ 644 if ((flags & FAN_MARK_IGNORED_MASK) && 645 !(flags & FAN_MARK_IGNORED_SURV_MODIFY) && 646 (atomic_read(&inode->i_writecount) > 0)) 647 return 0; 648 649 mutex_lock(&group->mark_mutex); 650 fsn_mark = fsnotify_find_inode_mark(group, inode); 651 if (!fsn_mark) { 652 fsn_mark = fanotify_add_new_mark(group, inode, NULL); 653 if (IS_ERR(fsn_mark)) { 654 mutex_unlock(&group->mark_mutex); 655 return PTR_ERR(fsn_mark); 656 } 657 } 658 added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); 659 mutex_unlock(&group->mark_mutex); 660 661 if (added & ~inode->i_fsnotify_mask) 662 fsnotify_recalc_inode_mask(inode); 663 664 fsnotify_put_mark(fsn_mark); 665 return 0; 666 } 667 668 /* fanotify syscalls */ 669 SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) 670 { 671 struct fsnotify_group *group; 672 int f_flags, fd; 673 struct user_struct *user; 674 struct fanotify_event_info *oevent; 675 676 pr_debug("%s: flags=%d event_f_flags=%d\n", 677 __func__, flags, event_f_flags); 678 679 if (!capable(CAP_SYS_ADMIN)) 680 return -EPERM; 681 682 if (flags & ~FAN_ALL_INIT_FLAGS) 683 return -EINVAL; 684 685 if (event_f_flags & ~FANOTIFY_INIT_ALL_EVENT_F_BITS) 686 return -EINVAL; 687 688 switch (event_f_flags & O_ACCMODE) { 689 case O_RDONLY: 690 case O_RDWR: 691 case O_WRONLY: 692 break; 693 default: 694 return -EINVAL; 695 } 696 697 user = get_current_user(); 698 if (atomic_read(&user->fanotify_listeners) > FANOTIFY_DEFAULT_MAX_LISTENERS) { 699 free_uid(user); 700 return -EMFILE; 701 } 702 703 f_flags = O_RDWR | FMODE_NONOTIFY; 704 if (flags & FAN_CLOEXEC) 705 f_flags |= O_CLOEXEC; 706 if (flags & FAN_NONBLOCK) 707 f_flags |= O_NONBLOCK; 708 709 /* fsnotify_alloc_group takes a ref. Dropped in fanotify_release */ 710 group = fsnotify_alloc_group(&fanotify_fsnotify_ops); 711 if (IS_ERR(group)) { 712 free_uid(user); 713 return PTR_ERR(group); 714 } 715 716 group->fanotify_data.user = user; 717 atomic_inc(&user->fanotify_listeners); 718 719 oevent = fanotify_alloc_event(NULL, FS_Q_OVERFLOW, NULL); 720 if (unlikely(!oevent)) { 721 fd = -ENOMEM; 722 goto out_destroy_group; 723 } 724 group->overflow_event = &oevent->fse; 725 726 if (force_o_largefile()) 727 event_f_flags |= O_LARGEFILE; 728 group->fanotify_data.f_flags = event_f_flags; 729 #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS 730 spin_lock_init(&group->fanotify_data.access_lock); 731 init_waitqueue_head(&group->fanotify_data.access_waitq); 732 INIT_LIST_HEAD(&group->fanotify_data.access_list); 733 atomic_set(&group->fanotify_data.bypass_perm, 0); 734 #endif 735 switch (flags & FAN_ALL_CLASS_BITS) { 736 case FAN_CLASS_NOTIF: 737 group->priority = FS_PRIO_0; 738 break; 739 case FAN_CLASS_CONTENT: 740 group->priority = FS_PRIO_1; 741 break; 742 case FAN_CLASS_PRE_CONTENT: 743 group->priority = FS_PRIO_2; 744 break; 745 default: 746 fd = -EINVAL; 747 goto out_destroy_group; 748 } 749 750 if (flags & FAN_UNLIMITED_QUEUE) { 751 fd = -EPERM; 752 if (!capable(CAP_SYS_ADMIN)) 753 goto out_destroy_group; 754 group->max_events = UINT_MAX; 755 } else { 756 group->max_events = FANOTIFY_DEFAULT_MAX_EVENTS; 757 } 758 759 if (flags & FAN_UNLIMITED_MARKS) { 760 fd = -EPERM; 761 if (!capable(CAP_SYS_ADMIN)) 762 goto out_destroy_group; 763 group->fanotify_data.max_marks = UINT_MAX; 764 } else { 765 group->fanotify_data.max_marks = FANOTIFY_DEFAULT_MAX_MARKS; 766 } 767 768 fd = anon_inode_getfd("[fanotify]", &fanotify_fops, group, f_flags); 769 if (fd < 0) 770 goto out_destroy_group; 771 772 return fd; 773 774 out_destroy_group: 775 fsnotify_destroy_group(group); 776 return fd; 777 } 778 779 SYSCALL_DEFINE5(fanotify_mark, int, fanotify_fd, unsigned int, flags, 780 __u64, mask, int, dfd, 781 const char __user *, pathname) 782 { 783 struct inode *inode = NULL; 784 struct vfsmount *mnt = NULL; 785 struct fsnotify_group *group; 786 struct fd f; 787 struct path path; 788 int ret; 789 790 pr_debug("%s: fanotify_fd=%d flags=%x dfd=%d pathname=%p mask=%llx\n", 791 __func__, fanotify_fd, flags, dfd, pathname, mask); 792 793 /* we only use the lower 32 bits as of right now. */ 794 if (mask & ((__u64)0xffffffff << 32)) 795 return -EINVAL; 796 797 if (flags & ~FAN_ALL_MARK_FLAGS) 798 return -EINVAL; 799 switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) { 800 case FAN_MARK_ADD: /* fallthrough */ 801 case FAN_MARK_REMOVE: 802 if (!mask) 803 return -EINVAL; 804 break; 805 case FAN_MARK_FLUSH: 806 if (flags & ~(FAN_MARK_MOUNT | FAN_MARK_FLUSH)) 807 return -EINVAL; 808 break; 809 default: 810 return -EINVAL; 811 } 812 813 if (mask & FAN_ONDIR) { 814 flags |= FAN_MARK_ONDIR; 815 mask &= ~FAN_ONDIR; 816 } 817 818 #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS 819 if (mask & ~(FAN_ALL_EVENTS | FAN_ALL_PERM_EVENTS | FAN_EVENT_ON_CHILD)) 820 #else 821 if (mask & ~(FAN_ALL_EVENTS | FAN_EVENT_ON_CHILD)) 822 #endif 823 return -EINVAL; 824 825 f = fdget(fanotify_fd); 826 if (unlikely(!f.file)) 827 return -EBADF; 828 829 /* verify that this is indeed an fanotify instance */ 830 ret = -EINVAL; 831 if (unlikely(f.file->f_op != &fanotify_fops)) 832 goto fput_and_out; 833 group = f.file->private_data; 834 835 /* 836 * group->priority == FS_PRIO_0 == FAN_CLASS_NOTIF. These are not 837 * allowed to set permissions events. 838 */ 839 ret = -EINVAL; 840 if (mask & FAN_ALL_PERM_EVENTS && 841 group->priority == FS_PRIO_0) 842 goto fput_and_out; 843 844 if (flags & FAN_MARK_FLUSH) { 845 ret = 0; 846 if (flags & FAN_MARK_MOUNT) 847 fsnotify_clear_vfsmount_marks_by_group(group); 848 else 849 fsnotify_clear_inode_marks_by_group(group); 850 goto fput_and_out; 851 } 852 853 ret = fanotify_find_path(dfd, pathname, &path, flags); 854 if (ret) 855 goto fput_and_out; 856 857 /* inode held in place by reference to path; group by fget on fd */ 858 if (!(flags & FAN_MARK_MOUNT)) 859 inode = path.dentry->d_inode; 860 else 861 mnt = path.mnt; 862 863 /* create/update an inode mark */ 864 switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE)) { 865 case FAN_MARK_ADD: 866 if (flags & FAN_MARK_MOUNT) 867 ret = fanotify_add_vfsmount_mark(group, mnt, mask, flags); 868 else 869 ret = fanotify_add_inode_mark(group, inode, mask, flags); 870 break; 871 case FAN_MARK_REMOVE: 872 if (flags & FAN_MARK_MOUNT) 873 ret = fanotify_remove_vfsmount_mark(group, mnt, mask, flags); 874 else 875 ret = fanotify_remove_inode_mark(group, inode, mask, flags); 876 break; 877 default: 878 ret = -EINVAL; 879 } 880 881 path_put(&path); 882 fput_and_out: 883 fdput(f); 884 return ret; 885 } 886 887 #ifdef CONFIG_COMPAT 888 COMPAT_SYSCALL_DEFINE6(fanotify_mark, 889 int, fanotify_fd, unsigned int, flags, 890 __u32, mask0, __u32, mask1, int, dfd, 891 const char __user *, pathname) 892 { 893 return sys_fanotify_mark(fanotify_fd, flags, 894 #ifdef __BIG_ENDIAN 895 ((__u64)mask0 << 32) | mask1, 896 #else 897 ((__u64)mask1 << 32) | mask0, 898 #endif 899 dfd, pathname); 900 } 901 #endif 902 903 /* 904 * fanotify_user_setup - Our initialization function. Note that we cannot return 905 * error because we have compiled-in VFS hooks. So an (unlikely) failure here 906 * must result in panic(). 907 */ 908 static int __init fanotify_user_setup(void) 909 { 910 fanotify_mark_cache = KMEM_CACHE(fsnotify_mark, SLAB_PANIC); 911 fanotify_event_cachep = KMEM_CACHE(fanotify_event_info, SLAB_PANIC); 912 #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS 913 fanotify_perm_event_cachep = KMEM_CACHE(fanotify_perm_event_info, 914 SLAB_PANIC); 915 #endif 916 917 return 0; 918 } 919 device_initcall(fanotify_user_setup); 920