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 23 #define FANOTIFY_DEFAULT_MAX_EVENTS 16384 24 #define FANOTIFY_DEFAULT_MAX_MARKS 8192 25 #define FANOTIFY_DEFAULT_MAX_LISTENERS 128 26 27 extern const struct fsnotify_ops fanotify_fsnotify_ops; 28 29 static struct kmem_cache *fanotify_mark_cache __read_mostly; 30 static struct kmem_cache *fanotify_response_event_cache __read_mostly; 31 32 struct fanotify_response_event { 33 struct list_head list; 34 __s32 fd; 35 struct fsnotify_event *event; 36 }; 37 38 /* 39 * Get an fsnotify notification event if one exists and is small 40 * enough to fit in "count". Return an error pointer if the count 41 * is not large enough. 42 * 43 * Called with the group->notification_mutex held. 44 */ 45 static struct fsnotify_event *get_one_event(struct fsnotify_group *group, 46 size_t count) 47 { 48 BUG_ON(!mutex_is_locked(&group->notification_mutex)); 49 50 pr_debug("%s: group=%p count=%zd\n", __func__, group, count); 51 52 if (fsnotify_notify_queue_is_empty(group)) 53 return NULL; 54 55 if (FAN_EVENT_METADATA_LEN > count) 56 return ERR_PTR(-EINVAL); 57 58 /* held the notification_mutex the whole time, so this is the 59 * same event we peeked above */ 60 return fsnotify_remove_notify_event(group); 61 } 62 63 static int create_fd(struct fsnotify_group *group, 64 struct fsnotify_event *event, 65 struct file **file) 66 { 67 int client_fd; 68 struct file *new_file; 69 70 pr_debug("%s: group=%p event=%p\n", __func__, group, event); 71 72 client_fd = get_unused_fd(); 73 if (client_fd < 0) 74 return client_fd; 75 76 if (event->data_type != FSNOTIFY_EVENT_PATH) { 77 WARN_ON(1); 78 put_unused_fd(client_fd); 79 return -EINVAL; 80 } 81 82 /* 83 * we need a new file handle for the userspace program so it can read even if it was 84 * originally opened O_WRONLY. 85 */ 86 /* it's possible this event was an overflow event. in that case dentry and mnt 87 * are NULL; That's fine, just don't call dentry open */ 88 if (event->path.dentry && event->path.mnt) 89 new_file = dentry_open(&event->path, 90 group->fanotify_data.f_flags | FMODE_NONOTIFY, 91 current_cred()); 92 else 93 new_file = ERR_PTR(-EOVERFLOW); 94 if (IS_ERR(new_file)) { 95 /* 96 * we still send an event even if we can't open the file. this 97 * can happen when say tasks are gone and we try to open their 98 * /proc files or we try to open a WRONLY file like in sysfs 99 * we just send the errno to userspace since there isn't much 100 * else we can do. 101 */ 102 put_unused_fd(client_fd); 103 client_fd = PTR_ERR(new_file); 104 } else { 105 *file = new_file; 106 } 107 108 return client_fd; 109 } 110 111 static int fill_event_metadata(struct fsnotify_group *group, 112 struct fanotify_event_metadata *metadata, 113 struct fsnotify_event *event, 114 struct file **file) 115 { 116 int ret = 0; 117 118 pr_debug("%s: group=%p metadata=%p event=%p\n", __func__, 119 group, metadata, event); 120 121 *file = NULL; 122 metadata->event_len = FAN_EVENT_METADATA_LEN; 123 metadata->metadata_len = FAN_EVENT_METADATA_LEN; 124 metadata->vers = FANOTIFY_METADATA_VERSION; 125 metadata->reserved = 0; 126 metadata->mask = event->mask & FAN_ALL_OUTGOING_EVENTS; 127 metadata->pid = pid_vnr(event->tgid); 128 if (unlikely(event->mask & FAN_Q_OVERFLOW)) 129 metadata->fd = FAN_NOFD; 130 else { 131 metadata->fd = create_fd(group, event, file); 132 if (metadata->fd < 0) 133 ret = metadata->fd; 134 } 135 136 return ret; 137 } 138 139 #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS 140 static struct fanotify_response_event *dequeue_re(struct fsnotify_group *group, 141 __s32 fd) 142 { 143 struct fanotify_response_event *re, *return_re = NULL; 144 145 mutex_lock(&group->fanotify_data.access_mutex); 146 list_for_each_entry(re, &group->fanotify_data.access_list, list) { 147 if (re->fd != fd) 148 continue; 149 150 list_del_init(&re->list); 151 return_re = re; 152 break; 153 } 154 mutex_unlock(&group->fanotify_data.access_mutex); 155 156 pr_debug("%s: found return_re=%p\n", __func__, return_re); 157 158 return return_re; 159 } 160 161 static int process_access_response(struct fsnotify_group *group, 162 struct fanotify_response *response_struct) 163 { 164 struct fanotify_response_event *re; 165 __s32 fd = response_struct->fd; 166 __u32 response = response_struct->response; 167 168 pr_debug("%s: group=%p fd=%d response=%d\n", __func__, group, 169 fd, response); 170 /* 171 * make sure the response is valid, if invalid we do nothing and either 172 * userspace can send a valid response or we will clean it up after the 173 * timeout 174 */ 175 switch (response) { 176 case FAN_ALLOW: 177 case FAN_DENY: 178 break; 179 default: 180 return -EINVAL; 181 } 182 183 if (fd < 0) 184 return -EINVAL; 185 186 re = dequeue_re(group, fd); 187 if (!re) 188 return -ENOENT; 189 190 re->event->response = response; 191 192 wake_up(&group->fanotify_data.access_waitq); 193 194 kmem_cache_free(fanotify_response_event_cache, re); 195 196 return 0; 197 } 198 199 static int prepare_for_access_response(struct fsnotify_group *group, 200 struct fsnotify_event *event, 201 __s32 fd) 202 { 203 struct fanotify_response_event *re; 204 205 if (!(event->mask & FAN_ALL_PERM_EVENTS)) 206 return 0; 207 208 re = kmem_cache_alloc(fanotify_response_event_cache, GFP_KERNEL); 209 if (!re) 210 return -ENOMEM; 211 212 re->event = event; 213 re->fd = fd; 214 215 mutex_lock(&group->fanotify_data.access_mutex); 216 217 if (atomic_read(&group->fanotify_data.bypass_perm)) { 218 mutex_unlock(&group->fanotify_data.access_mutex); 219 kmem_cache_free(fanotify_response_event_cache, re); 220 event->response = FAN_ALLOW; 221 return 0; 222 } 223 224 list_add_tail(&re->list, &group->fanotify_data.access_list); 225 mutex_unlock(&group->fanotify_data.access_mutex); 226 227 return 0; 228 } 229 230 #else 231 static int prepare_for_access_response(struct fsnotify_group *group, 232 struct fsnotify_event *event, 233 __s32 fd) 234 { 235 return 0; 236 } 237 238 #endif 239 240 static ssize_t copy_event_to_user(struct fsnotify_group *group, 241 struct fsnotify_event *event, 242 char __user *buf) 243 { 244 struct fanotify_event_metadata fanotify_event_metadata; 245 struct file *f; 246 int fd, ret; 247 248 pr_debug("%s: group=%p event=%p\n", __func__, group, event); 249 250 ret = fill_event_metadata(group, &fanotify_event_metadata, event, &f); 251 if (ret < 0) 252 goto out; 253 254 fd = fanotify_event_metadata.fd; 255 ret = -EFAULT; 256 if (copy_to_user(buf, &fanotify_event_metadata, 257 fanotify_event_metadata.event_len)) 258 goto out_close_fd; 259 260 ret = prepare_for_access_response(group, event, fd); 261 if (ret) 262 goto out_close_fd; 263 264 if (fd != FAN_NOFD) 265 fd_install(fd, f); 266 return fanotify_event_metadata.event_len; 267 268 out_close_fd: 269 if (fd != FAN_NOFD) { 270 put_unused_fd(fd); 271 fput(f); 272 } 273 out: 274 #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS 275 if (event->mask & FAN_ALL_PERM_EVENTS) { 276 event->response = FAN_DENY; 277 wake_up(&group->fanotify_data.access_waitq); 278 } 279 #endif 280 return ret; 281 } 282 283 /* intofiy userspace file descriptor functions */ 284 static unsigned int fanotify_poll(struct file *file, poll_table *wait) 285 { 286 struct fsnotify_group *group = file->private_data; 287 int ret = 0; 288 289 poll_wait(file, &group->notification_waitq, wait); 290 mutex_lock(&group->notification_mutex); 291 if (!fsnotify_notify_queue_is_empty(group)) 292 ret = POLLIN | POLLRDNORM; 293 mutex_unlock(&group->notification_mutex); 294 295 return ret; 296 } 297 298 static ssize_t fanotify_read(struct file *file, char __user *buf, 299 size_t count, loff_t *pos) 300 { 301 struct fsnotify_group *group; 302 struct fsnotify_event *kevent; 303 char __user *start; 304 int ret; 305 DEFINE_WAIT(wait); 306 307 start = buf; 308 group = file->private_data; 309 310 pr_debug("%s: group=%p\n", __func__, group); 311 312 while (1) { 313 prepare_to_wait(&group->notification_waitq, &wait, TASK_INTERRUPTIBLE); 314 315 mutex_lock(&group->notification_mutex); 316 kevent = get_one_event(group, count); 317 mutex_unlock(&group->notification_mutex); 318 319 if (kevent) { 320 ret = PTR_ERR(kevent); 321 if (IS_ERR(kevent)) 322 break; 323 ret = copy_event_to_user(group, kevent, buf); 324 fsnotify_put_event(kevent); 325 if (ret < 0) 326 break; 327 buf += ret; 328 count -= ret; 329 continue; 330 } 331 332 ret = -EAGAIN; 333 if (file->f_flags & O_NONBLOCK) 334 break; 335 ret = -ERESTARTSYS; 336 if (signal_pending(current)) 337 break; 338 339 if (start != buf) 340 break; 341 342 schedule(); 343 } 344 345 finish_wait(&group->notification_waitq, &wait); 346 if (start != buf && ret != -EFAULT) 347 ret = buf - start; 348 return ret; 349 } 350 351 static ssize_t fanotify_write(struct file *file, const char __user *buf, size_t count, loff_t *pos) 352 { 353 #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS 354 struct fanotify_response response = { .fd = -1, .response = -1 }; 355 struct fsnotify_group *group; 356 int ret; 357 358 group = file->private_data; 359 360 if (count > sizeof(response)) 361 count = sizeof(response); 362 363 pr_debug("%s: group=%p count=%zu\n", __func__, group, count); 364 365 if (copy_from_user(&response, buf, count)) 366 return -EFAULT; 367 368 ret = process_access_response(group, &response); 369 if (ret < 0) 370 count = ret; 371 372 return count; 373 #else 374 return -EINVAL; 375 #endif 376 } 377 378 static int fanotify_release(struct inode *ignored, struct file *file) 379 { 380 struct fsnotify_group *group = file->private_data; 381 382 #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS 383 struct fanotify_response_event *re, *lre; 384 385 mutex_lock(&group->fanotify_data.access_mutex); 386 387 atomic_inc(&group->fanotify_data.bypass_perm); 388 389 list_for_each_entry_safe(re, lre, &group->fanotify_data.access_list, list) { 390 pr_debug("%s: found group=%p re=%p event=%p\n", __func__, group, 391 re, re->event); 392 393 list_del_init(&re->list); 394 re->event->response = FAN_ALLOW; 395 396 kmem_cache_free(fanotify_response_event_cache, re); 397 } 398 mutex_unlock(&group->fanotify_data.access_mutex); 399 400 wake_up(&group->fanotify_data.access_waitq); 401 #endif 402 403 /* matches the fanotify_init->fsnotify_alloc_group */ 404 fsnotify_destroy_group(group); 405 406 return 0; 407 } 408 409 static long fanotify_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 410 { 411 struct fsnotify_group *group; 412 struct fsnotify_event_holder *holder; 413 void __user *p; 414 int ret = -ENOTTY; 415 size_t send_len = 0; 416 417 group = file->private_data; 418 419 p = (void __user *) arg; 420 421 switch (cmd) { 422 case FIONREAD: 423 mutex_lock(&group->notification_mutex); 424 list_for_each_entry(holder, &group->notification_list, event_list) 425 send_len += FAN_EVENT_METADATA_LEN; 426 mutex_unlock(&group->notification_mutex); 427 ret = put_user(send_len, (int __user *) p); 428 break; 429 } 430 431 return ret; 432 } 433 434 static const struct file_operations fanotify_fops = { 435 .show_fdinfo = fanotify_show_fdinfo, 436 .poll = fanotify_poll, 437 .read = fanotify_read, 438 .write = fanotify_write, 439 .fasync = NULL, 440 .release = fanotify_release, 441 .unlocked_ioctl = fanotify_ioctl, 442 .compat_ioctl = fanotify_ioctl, 443 .llseek = noop_llseek, 444 }; 445 446 static void fanotify_free_mark(struct fsnotify_mark *fsn_mark) 447 { 448 kmem_cache_free(fanotify_mark_cache, fsn_mark); 449 } 450 451 static int fanotify_find_path(int dfd, const char __user *filename, 452 struct path *path, unsigned int flags) 453 { 454 int ret; 455 456 pr_debug("%s: dfd=%d filename=%p flags=%x\n", __func__, 457 dfd, filename, flags); 458 459 if (filename == NULL) { 460 struct fd f = fdget(dfd); 461 462 ret = -EBADF; 463 if (!f.file) 464 goto out; 465 466 ret = -ENOTDIR; 467 if ((flags & FAN_MARK_ONLYDIR) && 468 !(S_ISDIR(file_inode(f.file)->i_mode))) { 469 fdput(f); 470 goto out; 471 } 472 473 *path = f.file->f_path; 474 path_get(path); 475 fdput(f); 476 } else { 477 unsigned int lookup_flags = 0; 478 479 if (!(flags & FAN_MARK_DONT_FOLLOW)) 480 lookup_flags |= LOOKUP_FOLLOW; 481 if (flags & FAN_MARK_ONLYDIR) 482 lookup_flags |= LOOKUP_DIRECTORY; 483 484 ret = user_path_at(dfd, filename, lookup_flags, path); 485 if (ret) 486 goto out; 487 } 488 489 /* you can only watch an inode if you have read permissions on it */ 490 ret = inode_permission(path->dentry->d_inode, MAY_READ); 491 if (ret) 492 path_put(path); 493 out: 494 return ret; 495 } 496 497 static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark, 498 __u32 mask, 499 unsigned int flags, 500 int *destroy) 501 { 502 __u32 oldmask; 503 504 spin_lock(&fsn_mark->lock); 505 if (!(flags & FAN_MARK_IGNORED_MASK)) { 506 oldmask = fsn_mark->mask; 507 fsnotify_set_mark_mask_locked(fsn_mark, (oldmask & ~mask)); 508 } else { 509 oldmask = fsn_mark->ignored_mask; 510 fsnotify_set_mark_ignored_mask_locked(fsn_mark, (oldmask & ~mask)); 511 } 512 spin_unlock(&fsn_mark->lock); 513 514 *destroy = !(oldmask & ~mask); 515 516 return mask & oldmask; 517 } 518 519 static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group, 520 struct vfsmount *mnt, __u32 mask, 521 unsigned int flags) 522 { 523 struct fsnotify_mark *fsn_mark = NULL; 524 __u32 removed; 525 int destroy_mark; 526 527 mutex_lock(&group->mark_mutex); 528 fsn_mark = fsnotify_find_vfsmount_mark(group, mnt); 529 if (!fsn_mark) { 530 mutex_unlock(&group->mark_mutex); 531 return -ENOENT; 532 } 533 534 removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags, 535 &destroy_mark); 536 if (destroy_mark) 537 fsnotify_destroy_mark_locked(fsn_mark, group); 538 mutex_unlock(&group->mark_mutex); 539 540 fsnotify_put_mark(fsn_mark); 541 if (removed & real_mount(mnt)->mnt_fsnotify_mask) 542 fsnotify_recalc_vfsmount_mask(mnt); 543 544 return 0; 545 } 546 547 static int fanotify_remove_inode_mark(struct fsnotify_group *group, 548 struct inode *inode, __u32 mask, 549 unsigned int flags) 550 { 551 struct fsnotify_mark *fsn_mark = NULL; 552 __u32 removed; 553 int destroy_mark; 554 555 mutex_lock(&group->mark_mutex); 556 fsn_mark = fsnotify_find_inode_mark(group, inode); 557 if (!fsn_mark) { 558 mutex_unlock(&group->mark_mutex); 559 return -ENOENT; 560 } 561 562 removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags, 563 &destroy_mark); 564 if (destroy_mark) 565 fsnotify_destroy_mark_locked(fsn_mark, group); 566 mutex_unlock(&group->mark_mutex); 567 568 /* matches the fsnotify_find_inode_mark() */ 569 fsnotify_put_mark(fsn_mark); 570 if (removed & inode->i_fsnotify_mask) 571 fsnotify_recalc_inode_mask(inode); 572 573 return 0; 574 } 575 576 static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark, 577 __u32 mask, 578 unsigned int flags) 579 { 580 __u32 oldmask = -1; 581 582 spin_lock(&fsn_mark->lock); 583 if (!(flags & FAN_MARK_IGNORED_MASK)) { 584 oldmask = fsn_mark->mask; 585 fsnotify_set_mark_mask_locked(fsn_mark, (oldmask | mask)); 586 } else { 587 __u32 tmask = fsn_mark->ignored_mask | mask; 588 fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask); 589 if (flags & FAN_MARK_IGNORED_SURV_MODIFY) 590 fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY; 591 } 592 593 if (!(flags & FAN_MARK_ONDIR)) { 594 __u32 tmask = fsn_mark->ignored_mask | FAN_ONDIR; 595 fsnotify_set_mark_ignored_mask_locked(fsn_mark, tmask); 596 } 597 598 spin_unlock(&fsn_mark->lock); 599 600 return mask & ~oldmask; 601 } 602 603 static struct fsnotify_mark *fanotify_add_new_mark(struct fsnotify_group *group, 604 struct inode *inode, 605 struct vfsmount *mnt) 606 { 607 struct fsnotify_mark *mark; 608 int ret; 609 610 if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks) 611 return ERR_PTR(-ENOSPC); 612 613 mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL); 614 if (!mark) 615 return ERR_PTR(-ENOMEM); 616 617 fsnotify_init_mark(mark, fanotify_free_mark); 618 ret = fsnotify_add_mark_locked(mark, group, inode, mnt, 0); 619 if (ret) { 620 fsnotify_put_mark(mark); 621 return ERR_PTR(ret); 622 } 623 624 return mark; 625 } 626 627 628 static int fanotify_add_vfsmount_mark(struct fsnotify_group *group, 629 struct vfsmount *mnt, __u32 mask, 630 unsigned int flags) 631 { 632 struct fsnotify_mark *fsn_mark; 633 __u32 added; 634 635 mutex_lock(&group->mark_mutex); 636 fsn_mark = fsnotify_find_vfsmount_mark(group, mnt); 637 if (!fsn_mark) { 638 fsn_mark = fanotify_add_new_mark(group, NULL, mnt); 639 if (IS_ERR(fsn_mark)) { 640 mutex_unlock(&group->mark_mutex); 641 return PTR_ERR(fsn_mark); 642 } 643 } 644 added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); 645 mutex_unlock(&group->mark_mutex); 646 647 if (added & ~real_mount(mnt)->mnt_fsnotify_mask) 648 fsnotify_recalc_vfsmount_mask(mnt); 649 650 fsnotify_put_mark(fsn_mark); 651 return 0; 652 } 653 654 static int fanotify_add_inode_mark(struct fsnotify_group *group, 655 struct inode *inode, __u32 mask, 656 unsigned int flags) 657 { 658 struct fsnotify_mark *fsn_mark; 659 __u32 added; 660 661 pr_debug("%s: group=%p inode=%p\n", __func__, group, inode); 662 663 /* 664 * If some other task has this inode open for write we should not add 665 * an ignored mark, unless that ignored mark is supposed to survive 666 * modification changes anyway. 667 */ 668 if ((flags & FAN_MARK_IGNORED_MASK) && 669 !(flags & FAN_MARK_IGNORED_SURV_MODIFY) && 670 (atomic_read(&inode->i_writecount) > 0)) 671 return 0; 672 673 mutex_lock(&group->mark_mutex); 674 fsn_mark = fsnotify_find_inode_mark(group, inode); 675 if (!fsn_mark) { 676 fsn_mark = fanotify_add_new_mark(group, inode, NULL); 677 if (IS_ERR(fsn_mark)) { 678 mutex_unlock(&group->mark_mutex); 679 return PTR_ERR(fsn_mark); 680 } 681 } 682 added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); 683 mutex_unlock(&group->mark_mutex); 684 685 if (added & ~inode->i_fsnotify_mask) 686 fsnotify_recalc_inode_mask(inode); 687 688 fsnotify_put_mark(fsn_mark); 689 return 0; 690 } 691 692 /* fanotify syscalls */ 693 SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) 694 { 695 struct fsnotify_group *group; 696 int f_flags, fd; 697 struct user_struct *user; 698 699 pr_debug("%s: flags=%d event_f_flags=%d\n", 700 __func__, flags, event_f_flags); 701 702 if (!capable(CAP_SYS_ADMIN)) 703 return -EPERM; 704 705 if (flags & ~FAN_ALL_INIT_FLAGS) 706 return -EINVAL; 707 708 user = get_current_user(); 709 if (atomic_read(&user->fanotify_listeners) > FANOTIFY_DEFAULT_MAX_LISTENERS) { 710 free_uid(user); 711 return -EMFILE; 712 } 713 714 f_flags = O_RDWR | FMODE_NONOTIFY; 715 if (flags & FAN_CLOEXEC) 716 f_flags |= O_CLOEXEC; 717 if (flags & FAN_NONBLOCK) 718 f_flags |= O_NONBLOCK; 719 720 /* fsnotify_alloc_group takes a ref. Dropped in fanotify_release */ 721 group = fsnotify_alloc_group(&fanotify_fsnotify_ops); 722 if (IS_ERR(group)) { 723 free_uid(user); 724 return PTR_ERR(group); 725 } 726 727 group->fanotify_data.user = user; 728 atomic_inc(&user->fanotify_listeners); 729 730 group->fanotify_data.f_flags = event_f_flags; 731 #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS 732 mutex_init(&group->fanotify_data.access_mutex); 733 init_waitqueue_head(&group->fanotify_data.access_waitq); 734 INIT_LIST_HEAD(&group->fanotify_data.access_list); 735 atomic_set(&group->fanotify_data.bypass_perm, 0); 736 #endif 737 switch (flags & FAN_ALL_CLASS_BITS) { 738 case FAN_CLASS_NOTIF: 739 group->priority = FS_PRIO_0; 740 break; 741 case FAN_CLASS_CONTENT: 742 group->priority = FS_PRIO_1; 743 break; 744 case FAN_CLASS_PRE_CONTENT: 745 group->priority = FS_PRIO_2; 746 break; 747 default: 748 fd = -EINVAL; 749 goto out_destroy_group; 750 } 751 752 if (flags & FAN_UNLIMITED_QUEUE) { 753 fd = -EPERM; 754 if (!capable(CAP_SYS_ADMIN)) 755 goto out_destroy_group; 756 group->max_events = UINT_MAX; 757 } else { 758 group->max_events = FANOTIFY_DEFAULT_MAX_EVENTS; 759 } 760 761 if (flags & FAN_UNLIMITED_MARKS) { 762 fd = -EPERM; 763 if (!capable(CAP_SYS_ADMIN)) 764 goto out_destroy_group; 765 group->fanotify_data.max_marks = UINT_MAX; 766 } else { 767 group->fanotify_data.max_marks = FANOTIFY_DEFAULT_MAX_MARKS; 768 } 769 770 fd = anon_inode_getfd("[fanotify]", &fanotify_fops, group, f_flags); 771 if (fd < 0) 772 goto out_destroy_group; 773 774 return fd; 775 776 out_destroy_group: 777 fsnotify_destroy_group(group); 778 return fd; 779 } 780 781 SYSCALL_DEFINE5(fanotify_mark, int, fanotify_fd, unsigned int, flags, 782 __u64, mask, int, dfd, 783 const char __user *, pathname) 784 { 785 struct inode *inode = NULL; 786 struct vfsmount *mnt = NULL; 787 struct fsnotify_group *group; 788 struct fd f; 789 struct path path; 790 int ret; 791 792 pr_debug("%s: fanotify_fd=%d flags=%x dfd=%d pathname=%p mask=%llx\n", 793 __func__, fanotify_fd, flags, dfd, pathname, mask); 794 795 /* we only use the lower 32 bits as of right now. */ 796 if (mask & ((__u64)0xffffffff << 32)) 797 return -EINVAL; 798 799 if (flags & ~FAN_ALL_MARK_FLAGS) 800 return -EINVAL; 801 switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) { 802 case FAN_MARK_ADD: /* fallthrough */ 803 case FAN_MARK_REMOVE: 804 if (!mask) 805 return -EINVAL; 806 case FAN_MARK_FLUSH: 807 break; 808 default: 809 return -EINVAL; 810 } 811 812 if (mask & FAN_ONDIR) { 813 flags |= FAN_MARK_ONDIR; 814 mask &= ~FAN_ONDIR; 815 } 816 817 #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS 818 if (mask & ~(FAN_ALL_EVENTS | FAN_ALL_PERM_EVENTS | FAN_EVENT_ON_CHILD)) 819 #else 820 if (mask & ~(FAN_ALL_EVENTS | FAN_EVENT_ON_CHILD)) 821 #endif 822 return -EINVAL; 823 824 f = fdget(fanotify_fd); 825 if (unlikely(!f.file)) 826 return -EBADF; 827 828 /* verify that this is indeed an fanotify instance */ 829 ret = -EINVAL; 830 if (unlikely(f.file->f_op != &fanotify_fops)) 831 goto fput_and_out; 832 group = f.file->private_data; 833 834 /* 835 * group->priority == FS_PRIO_0 == FAN_CLASS_NOTIF. These are not 836 * allowed to set permissions events. 837 */ 838 ret = -EINVAL; 839 if (mask & FAN_ALL_PERM_EVENTS && 840 group->priority == FS_PRIO_0) 841 goto fput_and_out; 842 843 ret = fanotify_find_path(dfd, pathname, &path, flags); 844 if (ret) 845 goto fput_and_out; 846 847 /* inode held in place by reference to path; group by fget on fd */ 848 if (!(flags & FAN_MARK_MOUNT)) 849 inode = path.dentry->d_inode; 850 else 851 mnt = path.mnt; 852 853 /* create/update an inode mark */ 854 switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) { 855 case FAN_MARK_ADD: 856 if (flags & FAN_MARK_MOUNT) 857 ret = fanotify_add_vfsmount_mark(group, mnt, mask, flags); 858 else 859 ret = fanotify_add_inode_mark(group, inode, mask, flags); 860 break; 861 case FAN_MARK_REMOVE: 862 if (flags & FAN_MARK_MOUNT) 863 ret = fanotify_remove_vfsmount_mark(group, mnt, mask, flags); 864 else 865 ret = fanotify_remove_inode_mark(group, inode, mask, flags); 866 break; 867 case FAN_MARK_FLUSH: 868 if (flags & FAN_MARK_MOUNT) 869 fsnotify_clear_vfsmount_marks_by_group(group); 870 else 871 fsnotify_clear_inode_marks_by_group(group); 872 break; 873 default: 874 ret = -EINVAL; 875 } 876 877 path_put(&path); 878 fput_and_out: 879 fdput(f); 880 return ret; 881 } 882 883 #ifdef CONFIG_COMPAT 884 COMPAT_SYSCALL_DEFINE6(fanotify_mark, 885 int, fanotify_fd, unsigned int, flags, 886 __u32, mask0, __u32, mask1, int, dfd, 887 const char __user *, pathname) 888 { 889 return sys_fanotify_mark(fanotify_fd, flags, 890 #ifdef __BIG_ENDIAN 891 ((__u64)mask1 << 32) | mask0, 892 #else 893 ((__u64)mask0 << 32) | mask1, 894 #endif 895 dfd, pathname); 896 } 897 #endif 898 899 /* 900 * fanotify_user_setup - Our initialization function. Note that we cannot return 901 * error because we have compiled-in VFS hooks. So an (unlikely) failure here 902 * must result in panic(). 903 */ 904 static int __init fanotify_user_setup(void) 905 { 906 fanotify_mark_cache = KMEM_CACHE(fsnotify_mark, SLAB_PANIC); 907 fanotify_response_event_cache = KMEM_CACHE(fanotify_response_event, 908 SLAB_PANIC); 909 910 return 0; 911 } 912 device_initcall(fanotify_user_setup); 913