1 /* 2 FUSE: Filesystem in Userspace 3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu> 4 5 This program can be distributed under the terms of the GNU GPL. 6 See the file COPYING. 7 */ 8 9 #include "fuse_i.h" 10 11 #include <linux/pagemap.h> 12 #include <linux/slab.h> 13 #include <linux/file.h> 14 #include <linux/seq_file.h> 15 #include <linux/init.h> 16 #include <linux/module.h> 17 #include <linux/moduleparam.h> 18 #include <linux/fs_context.h> 19 #include <linux/fs_parser.h> 20 #include <linux/statfs.h> 21 #include <linux/random.h> 22 #include <linux/sched.h> 23 #include <linux/exportfs.h> 24 #include <linux/posix_acl.h> 25 #include <linux/pid_namespace.h> 26 27 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); 28 MODULE_DESCRIPTION("Filesystem in Userspace"); 29 MODULE_LICENSE("GPL"); 30 31 static struct kmem_cache *fuse_inode_cachep; 32 struct list_head fuse_conn_list; 33 DEFINE_MUTEX(fuse_mutex); 34 35 static int set_global_limit(const char *val, const struct kernel_param *kp); 36 37 unsigned max_user_bgreq; 38 module_param_call(max_user_bgreq, set_global_limit, param_get_uint, 39 &max_user_bgreq, 0644); 40 __MODULE_PARM_TYPE(max_user_bgreq, "uint"); 41 MODULE_PARM_DESC(max_user_bgreq, 42 "Global limit for the maximum number of backgrounded requests an " 43 "unprivileged user can set"); 44 45 unsigned max_user_congthresh; 46 module_param_call(max_user_congthresh, set_global_limit, param_get_uint, 47 &max_user_congthresh, 0644); 48 __MODULE_PARM_TYPE(max_user_congthresh, "uint"); 49 MODULE_PARM_DESC(max_user_congthresh, 50 "Global limit for the maximum congestion threshold an " 51 "unprivileged user can set"); 52 53 #define FUSE_SUPER_MAGIC 0x65735546 54 55 #define FUSE_DEFAULT_BLKSIZE 512 56 57 /** Maximum number of outstanding background requests */ 58 #define FUSE_DEFAULT_MAX_BACKGROUND 12 59 60 /** Congestion starts at 75% of maximum */ 61 #define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4) 62 63 #ifdef CONFIG_BLOCK 64 static struct file_system_type fuseblk_fs_type; 65 #endif 66 67 struct fuse_forget_link *fuse_alloc_forget(void) 68 { 69 return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL_ACCOUNT); 70 } 71 72 static struct inode *fuse_alloc_inode(struct super_block *sb) 73 { 74 struct fuse_inode *fi; 75 76 fi = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL); 77 if (!fi) 78 return NULL; 79 80 fi->i_time = 0; 81 fi->inval_mask = 0; 82 fi->nodeid = 0; 83 fi->nlookup = 0; 84 fi->attr_version = 0; 85 fi->orig_ino = 0; 86 fi->state = 0; 87 mutex_init(&fi->mutex); 88 spin_lock_init(&fi->lock); 89 fi->forget = fuse_alloc_forget(); 90 if (!fi->forget) 91 goto out_free; 92 93 if (IS_ENABLED(CONFIG_FUSE_DAX) && !fuse_dax_inode_alloc(sb, fi)) 94 goto out_free_forget; 95 96 return &fi->inode; 97 98 out_free_forget: 99 kfree(fi->forget); 100 out_free: 101 kmem_cache_free(fuse_inode_cachep, fi); 102 return NULL; 103 } 104 105 static void fuse_free_inode(struct inode *inode) 106 { 107 struct fuse_inode *fi = get_fuse_inode(inode); 108 109 mutex_destroy(&fi->mutex); 110 kfree(fi->forget); 111 #ifdef CONFIG_FUSE_DAX 112 kfree(fi->dax); 113 #endif 114 kmem_cache_free(fuse_inode_cachep, fi); 115 } 116 117 static void fuse_evict_inode(struct inode *inode) 118 { 119 struct fuse_inode *fi = get_fuse_inode(inode); 120 121 truncate_inode_pages_final(&inode->i_data); 122 clear_inode(inode); 123 if (inode->i_sb->s_flags & SB_ACTIVE) { 124 struct fuse_conn *fc = get_fuse_conn(inode); 125 126 if (FUSE_IS_DAX(inode)) 127 fuse_dax_inode_cleanup(inode); 128 if (fi->nlookup) { 129 fuse_queue_forget(fc, fi->forget, fi->nodeid, 130 fi->nlookup); 131 fi->forget = NULL; 132 } 133 } 134 if (S_ISREG(inode->i_mode) && !fuse_is_bad(inode)) { 135 WARN_ON(!list_empty(&fi->write_files)); 136 WARN_ON(!list_empty(&fi->queued_writes)); 137 } 138 } 139 140 static int fuse_reconfigure(struct fs_context *fsc) 141 { 142 struct super_block *sb = fsc->root->d_sb; 143 144 sync_filesystem(sb); 145 if (fsc->sb_flags & SB_MANDLOCK) 146 return -EINVAL; 147 148 return 0; 149 } 150 151 /* 152 * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down 153 * so that it will fit. 154 */ 155 static ino_t fuse_squash_ino(u64 ino64) 156 { 157 ino_t ino = (ino_t) ino64; 158 if (sizeof(ino_t) < sizeof(u64)) 159 ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8; 160 return ino; 161 } 162 163 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr, 164 u64 attr_valid) 165 { 166 struct fuse_conn *fc = get_fuse_conn(inode); 167 struct fuse_inode *fi = get_fuse_inode(inode); 168 169 lockdep_assert_held(&fi->lock); 170 171 fi->attr_version = atomic64_inc_return(&fc->attr_version); 172 fi->i_time = attr_valid; 173 WRITE_ONCE(fi->inval_mask, 0); 174 175 inode->i_ino = fuse_squash_ino(attr->ino); 176 inode->i_mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777); 177 set_nlink(inode, attr->nlink); 178 inode->i_uid = make_kuid(fc->user_ns, attr->uid); 179 inode->i_gid = make_kgid(fc->user_ns, attr->gid); 180 inode->i_blocks = attr->blocks; 181 inode->i_atime.tv_sec = attr->atime; 182 inode->i_atime.tv_nsec = attr->atimensec; 183 /* mtime from server may be stale due to local buffered write */ 184 if (!fc->writeback_cache || !S_ISREG(inode->i_mode)) { 185 inode->i_mtime.tv_sec = attr->mtime; 186 inode->i_mtime.tv_nsec = attr->mtimensec; 187 inode->i_ctime.tv_sec = attr->ctime; 188 inode->i_ctime.tv_nsec = attr->ctimensec; 189 } 190 191 if (attr->blksize != 0) 192 inode->i_blkbits = ilog2(attr->blksize); 193 else 194 inode->i_blkbits = inode->i_sb->s_blocksize_bits; 195 196 /* 197 * Don't set the sticky bit in i_mode, unless we want the VFS 198 * to check permissions. This prevents failures due to the 199 * check in may_delete(). 200 */ 201 fi->orig_i_mode = inode->i_mode; 202 if (!fc->default_permissions) 203 inode->i_mode &= ~S_ISVTX; 204 205 fi->orig_ino = attr->ino; 206 207 /* 208 * We are refreshing inode data and it is possible that another 209 * client set suid/sgid or security.capability xattr. So clear 210 * S_NOSEC. Ideally, we could have cleared it only if suid/sgid 211 * was set or if security.capability xattr was set. But we don't 212 * know if security.capability has been set or not. So clear it 213 * anyway. Its less efficient but should be safe. 214 */ 215 inode->i_flags &= ~S_NOSEC; 216 } 217 218 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr, 219 u64 attr_valid, u64 attr_version) 220 { 221 struct fuse_conn *fc = get_fuse_conn(inode); 222 struct fuse_inode *fi = get_fuse_inode(inode); 223 bool is_wb = fc->writeback_cache; 224 loff_t oldsize; 225 struct timespec64 old_mtime; 226 227 spin_lock(&fi->lock); 228 if ((attr_version != 0 && fi->attr_version > attr_version) || 229 test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) { 230 spin_unlock(&fi->lock); 231 return; 232 } 233 234 old_mtime = inode->i_mtime; 235 fuse_change_attributes_common(inode, attr, attr_valid); 236 237 oldsize = inode->i_size; 238 /* 239 * In case of writeback_cache enabled, the cached writes beyond EOF 240 * extend local i_size without keeping userspace server in sync. So, 241 * attr->size coming from server can be stale. We cannot trust it. 242 */ 243 if (!is_wb || !S_ISREG(inode->i_mode)) 244 i_size_write(inode, attr->size); 245 spin_unlock(&fi->lock); 246 247 if (!is_wb && S_ISREG(inode->i_mode)) { 248 bool inval = false; 249 250 if (oldsize != attr->size) { 251 truncate_pagecache(inode, attr->size); 252 if (!fc->explicit_inval_data) 253 inval = true; 254 } else if (fc->auto_inval_data) { 255 struct timespec64 new_mtime = { 256 .tv_sec = attr->mtime, 257 .tv_nsec = attr->mtimensec, 258 }; 259 260 /* 261 * Auto inval mode also checks and invalidates if mtime 262 * has changed. 263 */ 264 if (!timespec64_equal(&old_mtime, &new_mtime)) 265 inval = true; 266 } 267 268 if (inval) 269 invalidate_inode_pages2(inode->i_mapping); 270 } 271 } 272 273 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr) 274 { 275 inode->i_mode = attr->mode & S_IFMT; 276 inode->i_size = attr->size; 277 inode->i_mtime.tv_sec = attr->mtime; 278 inode->i_mtime.tv_nsec = attr->mtimensec; 279 inode->i_ctime.tv_sec = attr->ctime; 280 inode->i_ctime.tv_nsec = attr->ctimensec; 281 if (S_ISREG(inode->i_mode)) { 282 fuse_init_common(inode); 283 fuse_init_file_inode(inode); 284 } else if (S_ISDIR(inode->i_mode)) 285 fuse_init_dir(inode); 286 else if (S_ISLNK(inode->i_mode)) 287 fuse_init_symlink(inode); 288 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) || 289 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) { 290 fuse_init_common(inode); 291 init_special_inode(inode, inode->i_mode, 292 new_decode_dev(attr->rdev)); 293 } else 294 BUG(); 295 } 296 297 static int fuse_inode_eq(struct inode *inode, void *_nodeidp) 298 { 299 u64 nodeid = *(u64 *) _nodeidp; 300 if (get_node_id(inode) == nodeid) 301 return 1; 302 else 303 return 0; 304 } 305 306 static int fuse_inode_set(struct inode *inode, void *_nodeidp) 307 { 308 u64 nodeid = *(u64 *) _nodeidp; 309 get_fuse_inode(inode)->nodeid = nodeid; 310 return 0; 311 } 312 313 struct inode *fuse_iget(struct super_block *sb, u64 nodeid, 314 int generation, struct fuse_attr *attr, 315 u64 attr_valid, u64 attr_version) 316 { 317 struct inode *inode; 318 struct fuse_inode *fi; 319 struct fuse_conn *fc = get_fuse_conn_super(sb); 320 321 /* 322 * Auto mount points get their node id from the submount root, which is 323 * not a unique identifier within this filesystem. 324 * 325 * To avoid conflicts, do not place submount points into the inode hash 326 * table. 327 */ 328 if (fc->auto_submounts && (attr->flags & FUSE_ATTR_SUBMOUNT) && 329 S_ISDIR(attr->mode)) { 330 inode = new_inode(sb); 331 if (!inode) 332 return NULL; 333 334 fuse_init_inode(inode, attr); 335 get_fuse_inode(inode)->nodeid = nodeid; 336 inode->i_flags |= S_AUTOMOUNT; 337 goto done; 338 } 339 340 retry: 341 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid); 342 if (!inode) 343 return NULL; 344 345 if ((inode->i_state & I_NEW)) { 346 inode->i_flags |= S_NOATIME; 347 if (!fc->writeback_cache || !S_ISREG(attr->mode)) 348 inode->i_flags |= S_NOCMTIME; 349 inode->i_generation = generation; 350 fuse_init_inode(inode, attr); 351 unlock_new_inode(inode); 352 } else if (fuse_stale_inode(inode, generation, attr)) { 353 /* nodeid was reused, any I/O on the old inode should fail */ 354 fuse_make_bad(inode); 355 iput(inode); 356 goto retry; 357 } 358 done: 359 fi = get_fuse_inode(inode); 360 spin_lock(&fi->lock); 361 fi->nlookup++; 362 spin_unlock(&fi->lock); 363 fuse_change_attributes(inode, attr, attr_valid, attr_version); 364 365 return inode; 366 } 367 368 struct inode *fuse_ilookup(struct fuse_conn *fc, u64 nodeid, 369 struct fuse_mount **fm) 370 { 371 struct fuse_mount *fm_iter; 372 struct inode *inode; 373 374 WARN_ON(!rwsem_is_locked(&fc->killsb)); 375 list_for_each_entry(fm_iter, &fc->mounts, fc_entry) { 376 if (!fm_iter->sb) 377 continue; 378 379 inode = ilookup5(fm_iter->sb, nodeid, fuse_inode_eq, &nodeid); 380 if (inode) { 381 if (fm) 382 *fm = fm_iter; 383 return inode; 384 } 385 } 386 387 return NULL; 388 } 389 390 int fuse_reverse_inval_inode(struct fuse_conn *fc, u64 nodeid, 391 loff_t offset, loff_t len) 392 { 393 struct fuse_inode *fi; 394 struct inode *inode; 395 pgoff_t pg_start; 396 pgoff_t pg_end; 397 398 inode = fuse_ilookup(fc, nodeid, NULL); 399 if (!inode) 400 return -ENOENT; 401 402 fi = get_fuse_inode(inode); 403 spin_lock(&fi->lock); 404 fi->attr_version = atomic64_inc_return(&fc->attr_version); 405 spin_unlock(&fi->lock); 406 407 fuse_invalidate_attr(inode); 408 forget_all_cached_acls(inode); 409 if (offset >= 0) { 410 pg_start = offset >> PAGE_SHIFT; 411 if (len <= 0) 412 pg_end = -1; 413 else 414 pg_end = (offset + len - 1) >> PAGE_SHIFT; 415 invalidate_inode_pages2_range(inode->i_mapping, 416 pg_start, pg_end); 417 } 418 iput(inode); 419 return 0; 420 } 421 422 bool fuse_lock_inode(struct inode *inode) 423 { 424 bool locked = false; 425 426 if (!get_fuse_conn(inode)->parallel_dirops) { 427 mutex_lock(&get_fuse_inode(inode)->mutex); 428 locked = true; 429 } 430 431 return locked; 432 } 433 434 void fuse_unlock_inode(struct inode *inode, bool locked) 435 { 436 if (locked) 437 mutex_unlock(&get_fuse_inode(inode)->mutex); 438 } 439 440 static void fuse_umount_begin(struct super_block *sb) 441 { 442 struct fuse_conn *fc = get_fuse_conn_super(sb); 443 444 if (!fc->no_force_umount) 445 fuse_abort_conn(fc); 446 } 447 448 static void fuse_send_destroy(struct fuse_mount *fm) 449 { 450 if (fm->fc->conn_init) { 451 FUSE_ARGS(args); 452 453 args.opcode = FUSE_DESTROY; 454 args.force = true; 455 args.nocreds = true; 456 fuse_simple_request(fm, &args); 457 } 458 } 459 460 static void fuse_put_super(struct super_block *sb) 461 { 462 struct fuse_mount *fm = get_fuse_mount_super(sb); 463 464 fuse_conn_put(fm->fc); 465 kfree(fm); 466 } 467 468 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr) 469 { 470 stbuf->f_type = FUSE_SUPER_MAGIC; 471 stbuf->f_bsize = attr->bsize; 472 stbuf->f_frsize = attr->frsize; 473 stbuf->f_blocks = attr->blocks; 474 stbuf->f_bfree = attr->bfree; 475 stbuf->f_bavail = attr->bavail; 476 stbuf->f_files = attr->files; 477 stbuf->f_ffree = attr->ffree; 478 stbuf->f_namelen = attr->namelen; 479 /* fsid is left zero */ 480 } 481 482 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf) 483 { 484 struct super_block *sb = dentry->d_sb; 485 struct fuse_mount *fm = get_fuse_mount_super(sb); 486 FUSE_ARGS(args); 487 struct fuse_statfs_out outarg; 488 int err; 489 490 if (!fuse_allow_current_process(fm->fc)) { 491 buf->f_type = FUSE_SUPER_MAGIC; 492 return 0; 493 } 494 495 memset(&outarg, 0, sizeof(outarg)); 496 args.in_numargs = 0; 497 args.opcode = FUSE_STATFS; 498 args.nodeid = get_node_id(d_inode(dentry)); 499 args.out_numargs = 1; 500 args.out_args[0].size = sizeof(outarg); 501 args.out_args[0].value = &outarg; 502 err = fuse_simple_request(fm, &args); 503 if (!err) 504 convert_fuse_statfs(buf, &outarg.st); 505 return err; 506 } 507 508 static struct fuse_sync_bucket *fuse_sync_bucket_alloc(void) 509 { 510 struct fuse_sync_bucket *bucket; 511 512 bucket = kzalloc(sizeof(*bucket), GFP_KERNEL | __GFP_NOFAIL); 513 if (bucket) { 514 init_waitqueue_head(&bucket->waitq); 515 /* Initial active count */ 516 atomic_set(&bucket->count, 1); 517 } 518 return bucket; 519 } 520 521 static void fuse_sync_fs_writes(struct fuse_conn *fc) 522 { 523 struct fuse_sync_bucket *bucket, *new_bucket; 524 int count; 525 526 new_bucket = fuse_sync_bucket_alloc(); 527 spin_lock(&fc->lock); 528 bucket = rcu_dereference_protected(fc->curr_bucket, 1); 529 count = atomic_read(&bucket->count); 530 WARN_ON(count < 1); 531 /* No outstanding writes? */ 532 if (count == 1) { 533 spin_unlock(&fc->lock); 534 kfree(new_bucket); 535 return; 536 } 537 538 /* 539 * Completion of new bucket depends on completion of this bucket, so add 540 * one more count. 541 */ 542 atomic_inc(&new_bucket->count); 543 rcu_assign_pointer(fc->curr_bucket, new_bucket); 544 spin_unlock(&fc->lock); 545 /* 546 * Drop initial active count. At this point if all writes in this and 547 * ancestor buckets complete, the count will go to zero and this task 548 * will be woken up. 549 */ 550 atomic_dec(&bucket->count); 551 552 wait_event(bucket->waitq, atomic_read(&bucket->count) == 0); 553 554 /* Drop temp count on descendant bucket */ 555 fuse_sync_bucket_dec(new_bucket); 556 kfree_rcu(bucket, rcu); 557 } 558 559 static int fuse_sync_fs(struct super_block *sb, int wait) 560 { 561 struct fuse_mount *fm = get_fuse_mount_super(sb); 562 struct fuse_conn *fc = fm->fc; 563 struct fuse_syncfs_in inarg; 564 FUSE_ARGS(args); 565 int err; 566 567 /* 568 * Userspace cannot handle the wait == 0 case. Avoid a 569 * gratuitous roundtrip. 570 */ 571 if (!wait) 572 return 0; 573 574 /* The filesystem is being unmounted. Nothing to do. */ 575 if (!sb->s_root) 576 return 0; 577 578 if (!fc->sync_fs) 579 return 0; 580 581 fuse_sync_fs_writes(fc); 582 583 memset(&inarg, 0, sizeof(inarg)); 584 args.in_numargs = 1; 585 args.in_args[0].size = sizeof(inarg); 586 args.in_args[0].value = &inarg; 587 args.opcode = FUSE_SYNCFS; 588 args.nodeid = get_node_id(sb->s_root->d_inode); 589 args.out_numargs = 0; 590 591 err = fuse_simple_request(fm, &args); 592 if (err == -ENOSYS) { 593 fc->sync_fs = 0; 594 err = 0; 595 } 596 597 return err; 598 } 599 600 enum { 601 OPT_SOURCE, 602 OPT_SUBTYPE, 603 OPT_FD, 604 OPT_ROOTMODE, 605 OPT_USER_ID, 606 OPT_GROUP_ID, 607 OPT_DEFAULT_PERMISSIONS, 608 OPT_ALLOW_OTHER, 609 OPT_MAX_READ, 610 OPT_BLKSIZE, 611 OPT_ERR 612 }; 613 614 static const struct fs_parameter_spec fuse_fs_parameters[] = { 615 fsparam_string ("source", OPT_SOURCE), 616 fsparam_u32 ("fd", OPT_FD), 617 fsparam_u32oct ("rootmode", OPT_ROOTMODE), 618 fsparam_u32 ("user_id", OPT_USER_ID), 619 fsparam_u32 ("group_id", OPT_GROUP_ID), 620 fsparam_flag ("default_permissions", OPT_DEFAULT_PERMISSIONS), 621 fsparam_flag ("allow_other", OPT_ALLOW_OTHER), 622 fsparam_u32 ("max_read", OPT_MAX_READ), 623 fsparam_u32 ("blksize", OPT_BLKSIZE), 624 fsparam_string ("subtype", OPT_SUBTYPE), 625 {} 626 }; 627 628 static int fuse_parse_param(struct fs_context *fsc, struct fs_parameter *param) 629 { 630 struct fs_parse_result result; 631 struct fuse_fs_context *ctx = fsc->fs_private; 632 int opt; 633 634 if (fsc->purpose == FS_CONTEXT_FOR_RECONFIGURE) { 635 /* 636 * Ignore options coming from mount(MS_REMOUNT) for backward 637 * compatibility. 638 */ 639 if (fsc->oldapi) 640 return 0; 641 642 return invalfc(fsc, "No changes allowed in reconfigure"); 643 } 644 645 opt = fs_parse(fsc, fuse_fs_parameters, param, &result); 646 if (opt < 0) 647 return opt; 648 649 switch (opt) { 650 case OPT_SOURCE: 651 if (fsc->source) 652 return invalfc(fsc, "Multiple sources specified"); 653 fsc->source = param->string; 654 param->string = NULL; 655 break; 656 657 case OPT_SUBTYPE: 658 if (ctx->subtype) 659 return invalfc(fsc, "Multiple subtypes specified"); 660 ctx->subtype = param->string; 661 param->string = NULL; 662 return 0; 663 664 case OPT_FD: 665 ctx->fd = result.uint_32; 666 ctx->fd_present = true; 667 break; 668 669 case OPT_ROOTMODE: 670 if (!fuse_valid_type(result.uint_32)) 671 return invalfc(fsc, "Invalid rootmode"); 672 ctx->rootmode = result.uint_32; 673 ctx->rootmode_present = true; 674 break; 675 676 case OPT_USER_ID: 677 ctx->user_id = make_kuid(fsc->user_ns, result.uint_32); 678 if (!uid_valid(ctx->user_id)) 679 return invalfc(fsc, "Invalid user_id"); 680 ctx->user_id_present = true; 681 break; 682 683 case OPT_GROUP_ID: 684 ctx->group_id = make_kgid(fsc->user_ns, result.uint_32); 685 if (!gid_valid(ctx->group_id)) 686 return invalfc(fsc, "Invalid group_id"); 687 ctx->group_id_present = true; 688 break; 689 690 case OPT_DEFAULT_PERMISSIONS: 691 ctx->default_permissions = true; 692 break; 693 694 case OPT_ALLOW_OTHER: 695 ctx->allow_other = true; 696 break; 697 698 case OPT_MAX_READ: 699 ctx->max_read = result.uint_32; 700 break; 701 702 case OPT_BLKSIZE: 703 if (!ctx->is_bdev) 704 return invalfc(fsc, "blksize only supported for fuseblk"); 705 ctx->blksize = result.uint_32; 706 break; 707 708 default: 709 return -EINVAL; 710 } 711 712 return 0; 713 } 714 715 static void fuse_free_fsc(struct fs_context *fsc) 716 { 717 struct fuse_fs_context *ctx = fsc->fs_private; 718 719 if (ctx) { 720 kfree(ctx->subtype); 721 kfree(ctx); 722 } 723 } 724 725 static int fuse_show_options(struct seq_file *m, struct dentry *root) 726 { 727 struct super_block *sb = root->d_sb; 728 struct fuse_conn *fc = get_fuse_conn_super(sb); 729 730 if (fc->legacy_opts_show) { 731 seq_printf(m, ",user_id=%u", 732 from_kuid_munged(fc->user_ns, fc->user_id)); 733 seq_printf(m, ",group_id=%u", 734 from_kgid_munged(fc->user_ns, fc->group_id)); 735 if (fc->default_permissions) 736 seq_puts(m, ",default_permissions"); 737 if (fc->allow_other) 738 seq_puts(m, ",allow_other"); 739 if (fc->max_read != ~0) 740 seq_printf(m, ",max_read=%u", fc->max_read); 741 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE) 742 seq_printf(m, ",blksize=%lu", sb->s_blocksize); 743 } 744 #ifdef CONFIG_FUSE_DAX 745 if (fc->dax) 746 seq_puts(m, ",dax"); 747 #endif 748 749 return 0; 750 } 751 752 static void fuse_iqueue_init(struct fuse_iqueue *fiq, 753 const struct fuse_iqueue_ops *ops, 754 void *priv) 755 { 756 memset(fiq, 0, sizeof(struct fuse_iqueue)); 757 spin_lock_init(&fiq->lock); 758 init_waitqueue_head(&fiq->waitq); 759 INIT_LIST_HEAD(&fiq->pending); 760 INIT_LIST_HEAD(&fiq->interrupts); 761 fiq->forget_list_tail = &fiq->forget_list_head; 762 fiq->connected = 1; 763 fiq->ops = ops; 764 fiq->priv = priv; 765 } 766 767 static void fuse_pqueue_init(struct fuse_pqueue *fpq) 768 { 769 unsigned int i; 770 771 spin_lock_init(&fpq->lock); 772 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) 773 INIT_LIST_HEAD(&fpq->processing[i]); 774 INIT_LIST_HEAD(&fpq->io); 775 fpq->connected = 1; 776 } 777 778 void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm, 779 struct user_namespace *user_ns, 780 const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv) 781 { 782 memset(fc, 0, sizeof(*fc)); 783 spin_lock_init(&fc->lock); 784 spin_lock_init(&fc->bg_lock); 785 init_rwsem(&fc->killsb); 786 refcount_set(&fc->count, 1); 787 atomic_set(&fc->dev_count, 1); 788 init_waitqueue_head(&fc->blocked_waitq); 789 fuse_iqueue_init(&fc->iq, fiq_ops, fiq_priv); 790 INIT_LIST_HEAD(&fc->bg_queue); 791 INIT_LIST_HEAD(&fc->entry); 792 INIT_LIST_HEAD(&fc->devices); 793 atomic_set(&fc->num_waiting, 0); 794 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND; 795 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD; 796 atomic64_set(&fc->khctr, 0); 797 fc->polled_files = RB_ROOT; 798 fc->blocked = 0; 799 fc->initialized = 0; 800 fc->connected = 1; 801 atomic64_set(&fc->attr_version, 1); 802 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key)); 803 fc->pid_ns = get_pid_ns(task_active_pid_ns(current)); 804 fc->user_ns = get_user_ns(user_ns); 805 fc->max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ; 806 fc->max_pages_limit = FUSE_MAX_MAX_PAGES; 807 808 INIT_LIST_HEAD(&fc->mounts); 809 list_add(&fm->fc_entry, &fc->mounts); 810 fm->fc = fc; 811 } 812 EXPORT_SYMBOL_GPL(fuse_conn_init); 813 814 void fuse_conn_put(struct fuse_conn *fc) 815 { 816 if (refcount_dec_and_test(&fc->count)) { 817 struct fuse_iqueue *fiq = &fc->iq; 818 struct fuse_sync_bucket *bucket; 819 820 if (IS_ENABLED(CONFIG_FUSE_DAX)) 821 fuse_dax_conn_free(fc); 822 if (fiq->ops->release) 823 fiq->ops->release(fiq); 824 put_pid_ns(fc->pid_ns); 825 put_user_ns(fc->user_ns); 826 bucket = rcu_dereference_protected(fc->curr_bucket, 1); 827 if (bucket) { 828 WARN_ON(atomic_read(&bucket->count) != 1); 829 kfree(bucket); 830 } 831 fc->release(fc); 832 } 833 } 834 EXPORT_SYMBOL_GPL(fuse_conn_put); 835 836 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc) 837 { 838 refcount_inc(&fc->count); 839 return fc; 840 } 841 EXPORT_SYMBOL_GPL(fuse_conn_get); 842 843 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode) 844 { 845 struct fuse_attr attr; 846 memset(&attr, 0, sizeof(attr)); 847 848 attr.mode = mode; 849 attr.ino = FUSE_ROOT_ID; 850 attr.nlink = 1; 851 return fuse_iget(sb, 1, 0, &attr, 0, 0); 852 } 853 854 struct fuse_inode_handle { 855 u64 nodeid; 856 u32 generation; 857 }; 858 859 static struct dentry *fuse_get_dentry(struct super_block *sb, 860 struct fuse_inode_handle *handle) 861 { 862 struct fuse_conn *fc = get_fuse_conn_super(sb); 863 struct inode *inode; 864 struct dentry *entry; 865 int err = -ESTALE; 866 867 if (handle->nodeid == 0) 868 goto out_err; 869 870 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid); 871 if (!inode) { 872 struct fuse_entry_out outarg; 873 const struct qstr name = QSTR_INIT(".", 1); 874 875 if (!fc->export_support) 876 goto out_err; 877 878 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg, 879 &inode); 880 if (err && err != -ENOENT) 881 goto out_err; 882 if (err || !inode) { 883 err = -ESTALE; 884 goto out_err; 885 } 886 err = -EIO; 887 if (get_node_id(inode) != handle->nodeid) 888 goto out_iput; 889 } 890 err = -ESTALE; 891 if (inode->i_generation != handle->generation) 892 goto out_iput; 893 894 entry = d_obtain_alias(inode); 895 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID) 896 fuse_invalidate_entry_cache(entry); 897 898 return entry; 899 900 out_iput: 901 iput(inode); 902 out_err: 903 return ERR_PTR(err); 904 } 905 906 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len, 907 struct inode *parent) 908 { 909 int len = parent ? 6 : 3; 910 u64 nodeid; 911 u32 generation; 912 913 if (*max_len < len) { 914 *max_len = len; 915 return FILEID_INVALID; 916 } 917 918 nodeid = get_fuse_inode(inode)->nodeid; 919 generation = inode->i_generation; 920 921 fh[0] = (u32)(nodeid >> 32); 922 fh[1] = (u32)(nodeid & 0xffffffff); 923 fh[2] = generation; 924 925 if (parent) { 926 nodeid = get_fuse_inode(parent)->nodeid; 927 generation = parent->i_generation; 928 929 fh[3] = (u32)(nodeid >> 32); 930 fh[4] = (u32)(nodeid & 0xffffffff); 931 fh[5] = generation; 932 } 933 934 *max_len = len; 935 return parent ? 0x82 : 0x81; 936 } 937 938 static struct dentry *fuse_fh_to_dentry(struct super_block *sb, 939 struct fid *fid, int fh_len, int fh_type) 940 { 941 struct fuse_inode_handle handle; 942 943 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3) 944 return NULL; 945 946 handle.nodeid = (u64) fid->raw[0] << 32; 947 handle.nodeid |= (u64) fid->raw[1]; 948 handle.generation = fid->raw[2]; 949 return fuse_get_dentry(sb, &handle); 950 } 951 952 static struct dentry *fuse_fh_to_parent(struct super_block *sb, 953 struct fid *fid, int fh_len, int fh_type) 954 { 955 struct fuse_inode_handle parent; 956 957 if (fh_type != 0x82 || fh_len < 6) 958 return NULL; 959 960 parent.nodeid = (u64) fid->raw[3] << 32; 961 parent.nodeid |= (u64) fid->raw[4]; 962 parent.generation = fid->raw[5]; 963 return fuse_get_dentry(sb, &parent); 964 } 965 966 static struct dentry *fuse_get_parent(struct dentry *child) 967 { 968 struct inode *child_inode = d_inode(child); 969 struct fuse_conn *fc = get_fuse_conn(child_inode); 970 struct inode *inode; 971 struct dentry *parent; 972 struct fuse_entry_out outarg; 973 int err; 974 975 if (!fc->export_support) 976 return ERR_PTR(-ESTALE); 977 978 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode), 979 &dotdot_name, &outarg, &inode); 980 if (err) { 981 if (err == -ENOENT) 982 return ERR_PTR(-ESTALE); 983 return ERR_PTR(err); 984 } 985 986 parent = d_obtain_alias(inode); 987 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID) 988 fuse_invalidate_entry_cache(parent); 989 990 return parent; 991 } 992 993 static const struct export_operations fuse_export_operations = { 994 .fh_to_dentry = fuse_fh_to_dentry, 995 .fh_to_parent = fuse_fh_to_parent, 996 .encode_fh = fuse_encode_fh, 997 .get_parent = fuse_get_parent, 998 }; 999 1000 static const struct super_operations fuse_super_operations = { 1001 .alloc_inode = fuse_alloc_inode, 1002 .free_inode = fuse_free_inode, 1003 .evict_inode = fuse_evict_inode, 1004 .write_inode = fuse_write_inode, 1005 .drop_inode = generic_delete_inode, 1006 .put_super = fuse_put_super, 1007 .umount_begin = fuse_umount_begin, 1008 .statfs = fuse_statfs, 1009 .sync_fs = fuse_sync_fs, 1010 .show_options = fuse_show_options, 1011 }; 1012 1013 static void sanitize_global_limit(unsigned *limit) 1014 { 1015 /* 1016 * The default maximum number of async requests is calculated to consume 1017 * 1/2^13 of the total memory, assuming 392 bytes per request. 1018 */ 1019 if (*limit == 0) 1020 *limit = ((totalram_pages() << PAGE_SHIFT) >> 13) / 392; 1021 1022 if (*limit >= 1 << 16) 1023 *limit = (1 << 16) - 1; 1024 } 1025 1026 static int set_global_limit(const char *val, const struct kernel_param *kp) 1027 { 1028 int rv; 1029 1030 rv = param_set_uint(val, kp); 1031 if (rv) 1032 return rv; 1033 1034 sanitize_global_limit((unsigned *)kp->arg); 1035 1036 return 0; 1037 } 1038 1039 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg) 1040 { 1041 int cap_sys_admin = capable(CAP_SYS_ADMIN); 1042 1043 if (arg->minor < 13) 1044 return; 1045 1046 sanitize_global_limit(&max_user_bgreq); 1047 sanitize_global_limit(&max_user_congthresh); 1048 1049 spin_lock(&fc->bg_lock); 1050 if (arg->max_background) { 1051 fc->max_background = arg->max_background; 1052 1053 if (!cap_sys_admin && fc->max_background > max_user_bgreq) 1054 fc->max_background = max_user_bgreq; 1055 } 1056 if (arg->congestion_threshold) { 1057 fc->congestion_threshold = arg->congestion_threshold; 1058 1059 if (!cap_sys_admin && 1060 fc->congestion_threshold > max_user_congthresh) 1061 fc->congestion_threshold = max_user_congthresh; 1062 } 1063 spin_unlock(&fc->bg_lock); 1064 } 1065 1066 struct fuse_init_args { 1067 struct fuse_args args; 1068 struct fuse_init_in in; 1069 struct fuse_init_out out; 1070 }; 1071 1072 static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args, 1073 int error) 1074 { 1075 struct fuse_conn *fc = fm->fc; 1076 struct fuse_init_args *ia = container_of(args, typeof(*ia), args); 1077 struct fuse_init_out *arg = &ia->out; 1078 bool ok = true; 1079 1080 if (error || arg->major != FUSE_KERNEL_VERSION) 1081 ok = false; 1082 else { 1083 unsigned long ra_pages; 1084 1085 process_init_limits(fc, arg); 1086 1087 if (arg->minor >= 6) { 1088 ra_pages = arg->max_readahead / PAGE_SIZE; 1089 if (arg->flags & FUSE_ASYNC_READ) 1090 fc->async_read = 1; 1091 if (!(arg->flags & FUSE_POSIX_LOCKS)) 1092 fc->no_lock = 1; 1093 if (arg->minor >= 17) { 1094 if (!(arg->flags & FUSE_FLOCK_LOCKS)) 1095 fc->no_flock = 1; 1096 } else { 1097 if (!(arg->flags & FUSE_POSIX_LOCKS)) 1098 fc->no_flock = 1; 1099 } 1100 if (arg->flags & FUSE_ATOMIC_O_TRUNC) 1101 fc->atomic_o_trunc = 1; 1102 if (arg->minor >= 9) { 1103 /* LOOKUP has dependency on proto version */ 1104 if (arg->flags & FUSE_EXPORT_SUPPORT) 1105 fc->export_support = 1; 1106 } 1107 if (arg->flags & FUSE_BIG_WRITES) 1108 fc->big_writes = 1; 1109 if (arg->flags & FUSE_DONT_MASK) 1110 fc->dont_mask = 1; 1111 if (arg->flags & FUSE_AUTO_INVAL_DATA) 1112 fc->auto_inval_data = 1; 1113 else if (arg->flags & FUSE_EXPLICIT_INVAL_DATA) 1114 fc->explicit_inval_data = 1; 1115 if (arg->flags & FUSE_DO_READDIRPLUS) { 1116 fc->do_readdirplus = 1; 1117 if (arg->flags & FUSE_READDIRPLUS_AUTO) 1118 fc->readdirplus_auto = 1; 1119 } 1120 if (arg->flags & FUSE_ASYNC_DIO) 1121 fc->async_dio = 1; 1122 if (arg->flags & FUSE_WRITEBACK_CACHE) 1123 fc->writeback_cache = 1; 1124 if (arg->flags & FUSE_PARALLEL_DIROPS) 1125 fc->parallel_dirops = 1; 1126 if (arg->flags & FUSE_HANDLE_KILLPRIV) 1127 fc->handle_killpriv = 1; 1128 if (arg->time_gran && arg->time_gran <= 1000000000) 1129 fm->sb->s_time_gran = arg->time_gran; 1130 if ((arg->flags & FUSE_POSIX_ACL)) { 1131 fc->default_permissions = 1; 1132 fc->posix_acl = 1; 1133 fm->sb->s_xattr = fuse_acl_xattr_handlers; 1134 } 1135 if (arg->flags & FUSE_CACHE_SYMLINKS) 1136 fc->cache_symlinks = 1; 1137 if (arg->flags & FUSE_ABORT_ERROR) 1138 fc->abort_err = 1; 1139 if (arg->flags & FUSE_MAX_PAGES) { 1140 fc->max_pages = 1141 min_t(unsigned int, fc->max_pages_limit, 1142 max_t(unsigned int, arg->max_pages, 1)); 1143 } 1144 if (IS_ENABLED(CONFIG_FUSE_DAX) && 1145 arg->flags & FUSE_MAP_ALIGNMENT && 1146 !fuse_dax_check_alignment(fc, arg->map_alignment)) { 1147 ok = false; 1148 } 1149 if (arg->flags & FUSE_HANDLE_KILLPRIV_V2) { 1150 fc->handle_killpriv_v2 = 1; 1151 fm->sb->s_flags |= SB_NOSEC; 1152 } 1153 if (arg->flags & FUSE_SETXATTR_EXT) 1154 fc->setxattr_ext = 1; 1155 } else { 1156 ra_pages = fc->max_read / PAGE_SIZE; 1157 fc->no_lock = 1; 1158 fc->no_flock = 1; 1159 } 1160 1161 fm->sb->s_bdi->ra_pages = 1162 min(fm->sb->s_bdi->ra_pages, ra_pages); 1163 fc->minor = arg->minor; 1164 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write; 1165 fc->max_write = max_t(unsigned, 4096, fc->max_write); 1166 fc->conn_init = 1; 1167 } 1168 kfree(ia); 1169 1170 if (!ok) { 1171 fc->conn_init = 0; 1172 fc->conn_error = 1; 1173 } 1174 1175 fuse_set_initialized(fc); 1176 wake_up_all(&fc->blocked_waitq); 1177 } 1178 1179 void fuse_send_init(struct fuse_mount *fm) 1180 { 1181 struct fuse_init_args *ia; 1182 1183 ia = kzalloc(sizeof(*ia), GFP_KERNEL | __GFP_NOFAIL); 1184 1185 ia->in.major = FUSE_KERNEL_VERSION; 1186 ia->in.minor = FUSE_KERNEL_MINOR_VERSION; 1187 ia->in.max_readahead = fm->sb->s_bdi->ra_pages * PAGE_SIZE; 1188 ia->in.flags |= 1189 FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC | 1190 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK | 1191 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ | 1192 FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA | 1193 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO | 1194 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT | 1195 FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL | 1196 FUSE_ABORT_ERROR | FUSE_MAX_PAGES | FUSE_CACHE_SYMLINKS | 1197 FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA | 1198 FUSE_HANDLE_KILLPRIV_V2 | FUSE_SETXATTR_EXT; 1199 #ifdef CONFIG_FUSE_DAX 1200 if (fm->fc->dax) 1201 ia->in.flags |= FUSE_MAP_ALIGNMENT; 1202 #endif 1203 if (fm->fc->auto_submounts) 1204 ia->in.flags |= FUSE_SUBMOUNTS; 1205 1206 ia->args.opcode = FUSE_INIT; 1207 ia->args.in_numargs = 1; 1208 ia->args.in_args[0].size = sizeof(ia->in); 1209 ia->args.in_args[0].value = &ia->in; 1210 ia->args.out_numargs = 1; 1211 /* Variable length argument used for backward compatibility 1212 with interface version < 7.5. Rest of init_out is zeroed 1213 by do_get_request(), so a short reply is not a problem */ 1214 ia->args.out_argvar = true; 1215 ia->args.out_args[0].size = sizeof(ia->out); 1216 ia->args.out_args[0].value = &ia->out; 1217 ia->args.force = true; 1218 ia->args.nocreds = true; 1219 ia->args.end = process_init_reply; 1220 1221 if (fuse_simple_background(fm, &ia->args, GFP_KERNEL) != 0) 1222 process_init_reply(fm, &ia->args, -ENOTCONN); 1223 } 1224 EXPORT_SYMBOL_GPL(fuse_send_init); 1225 1226 void fuse_free_conn(struct fuse_conn *fc) 1227 { 1228 WARN_ON(!list_empty(&fc->devices)); 1229 kfree_rcu(fc, rcu); 1230 } 1231 EXPORT_SYMBOL_GPL(fuse_free_conn); 1232 1233 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb) 1234 { 1235 int err; 1236 char *suffix = ""; 1237 1238 if (sb->s_bdev) { 1239 suffix = "-fuseblk"; 1240 /* 1241 * sb->s_bdi points to blkdev's bdi however we want to redirect 1242 * it to our private bdi... 1243 */ 1244 bdi_put(sb->s_bdi); 1245 sb->s_bdi = &noop_backing_dev_info; 1246 } 1247 err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev), 1248 MINOR(fc->dev), suffix); 1249 if (err) 1250 return err; 1251 1252 /* fuse does it's own writeback accounting */ 1253 sb->s_bdi->capabilities &= ~BDI_CAP_WRITEBACK_ACCT; 1254 sb->s_bdi->capabilities |= BDI_CAP_STRICTLIMIT; 1255 1256 /* 1257 * For a single fuse filesystem use max 1% of dirty + 1258 * writeback threshold. 1259 * 1260 * This gives about 1M of write buffer for memory maps on a 1261 * machine with 1G and 10% dirty_ratio, which should be more 1262 * than enough. 1263 * 1264 * Privileged users can raise it by writing to 1265 * 1266 * /sys/class/bdi/<bdi>/max_ratio 1267 */ 1268 bdi_set_max_ratio(sb->s_bdi, 1); 1269 1270 return 0; 1271 } 1272 1273 struct fuse_dev *fuse_dev_alloc(void) 1274 { 1275 struct fuse_dev *fud; 1276 struct list_head *pq; 1277 1278 fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL); 1279 if (!fud) 1280 return NULL; 1281 1282 pq = kcalloc(FUSE_PQ_HASH_SIZE, sizeof(struct list_head), GFP_KERNEL); 1283 if (!pq) { 1284 kfree(fud); 1285 return NULL; 1286 } 1287 1288 fud->pq.processing = pq; 1289 fuse_pqueue_init(&fud->pq); 1290 1291 return fud; 1292 } 1293 EXPORT_SYMBOL_GPL(fuse_dev_alloc); 1294 1295 void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc) 1296 { 1297 fud->fc = fuse_conn_get(fc); 1298 spin_lock(&fc->lock); 1299 list_add_tail(&fud->entry, &fc->devices); 1300 spin_unlock(&fc->lock); 1301 } 1302 EXPORT_SYMBOL_GPL(fuse_dev_install); 1303 1304 struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc) 1305 { 1306 struct fuse_dev *fud; 1307 1308 fud = fuse_dev_alloc(); 1309 if (!fud) 1310 return NULL; 1311 1312 fuse_dev_install(fud, fc); 1313 return fud; 1314 } 1315 EXPORT_SYMBOL_GPL(fuse_dev_alloc_install); 1316 1317 void fuse_dev_free(struct fuse_dev *fud) 1318 { 1319 struct fuse_conn *fc = fud->fc; 1320 1321 if (fc) { 1322 spin_lock(&fc->lock); 1323 list_del(&fud->entry); 1324 spin_unlock(&fc->lock); 1325 1326 fuse_conn_put(fc); 1327 } 1328 kfree(fud->pq.processing); 1329 kfree(fud); 1330 } 1331 EXPORT_SYMBOL_GPL(fuse_dev_free); 1332 1333 static void fuse_fill_attr_from_inode(struct fuse_attr *attr, 1334 const struct fuse_inode *fi) 1335 { 1336 *attr = (struct fuse_attr){ 1337 .ino = fi->inode.i_ino, 1338 .size = fi->inode.i_size, 1339 .blocks = fi->inode.i_blocks, 1340 .atime = fi->inode.i_atime.tv_sec, 1341 .mtime = fi->inode.i_mtime.tv_sec, 1342 .ctime = fi->inode.i_ctime.tv_sec, 1343 .atimensec = fi->inode.i_atime.tv_nsec, 1344 .mtimensec = fi->inode.i_mtime.tv_nsec, 1345 .ctimensec = fi->inode.i_ctime.tv_nsec, 1346 .mode = fi->inode.i_mode, 1347 .nlink = fi->inode.i_nlink, 1348 .uid = fi->inode.i_uid.val, 1349 .gid = fi->inode.i_gid.val, 1350 .rdev = fi->inode.i_rdev, 1351 .blksize = 1u << fi->inode.i_blkbits, 1352 }; 1353 } 1354 1355 static void fuse_sb_defaults(struct super_block *sb) 1356 { 1357 sb->s_magic = FUSE_SUPER_MAGIC; 1358 sb->s_op = &fuse_super_operations; 1359 sb->s_xattr = fuse_xattr_handlers; 1360 sb->s_maxbytes = MAX_LFS_FILESIZE; 1361 sb->s_time_gran = 1; 1362 sb->s_export_op = &fuse_export_operations; 1363 sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE; 1364 if (sb->s_user_ns != &init_user_ns) 1365 sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER; 1366 sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION); 1367 1368 /* 1369 * If we are not in the initial user namespace posix 1370 * acls must be translated. 1371 */ 1372 if (sb->s_user_ns != &init_user_ns) 1373 sb->s_xattr = fuse_no_acl_xattr_handlers; 1374 } 1375 1376 static int fuse_fill_super_submount(struct super_block *sb, 1377 struct fuse_inode *parent_fi) 1378 { 1379 struct fuse_mount *fm = get_fuse_mount_super(sb); 1380 struct super_block *parent_sb = parent_fi->inode.i_sb; 1381 struct fuse_attr root_attr; 1382 struct inode *root; 1383 1384 fuse_sb_defaults(sb); 1385 fm->sb = sb; 1386 1387 WARN_ON(sb->s_bdi != &noop_backing_dev_info); 1388 sb->s_bdi = bdi_get(parent_sb->s_bdi); 1389 1390 sb->s_xattr = parent_sb->s_xattr; 1391 sb->s_time_gran = parent_sb->s_time_gran; 1392 sb->s_blocksize = parent_sb->s_blocksize; 1393 sb->s_blocksize_bits = parent_sb->s_blocksize_bits; 1394 sb->s_subtype = kstrdup(parent_sb->s_subtype, GFP_KERNEL); 1395 if (parent_sb->s_subtype && !sb->s_subtype) 1396 return -ENOMEM; 1397 1398 fuse_fill_attr_from_inode(&root_attr, parent_fi); 1399 root = fuse_iget(sb, parent_fi->nodeid, 0, &root_attr, 0, 0); 1400 /* 1401 * This inode is just a duplicate, so it is not looked up and 1402 * its nlookup should not be incremented. fuse_iget() does 1403 * that, though, so undo it here. 1404 */ 1405 get_fuse_inode(root)->nlookup--; 1406 sb->s_d_op = &fuse_dentry_operations; 1407 sb->s_root = d_make_root(root); 1408 if (!sb->s_root) 1409 return -ENOMEM; 1410 1411 return 0; 1412 } 1413 1414 /* Filesystem context private data holds the FUSE inode of the mount point */ 1415 static int fuse_get_tree_submount(struct fs_context *fsc) 1416 { 1417 struct fuse_mount *fm; 1418 struct fuse_inode *mp_fi = fsc->fs_private; 1419 struct fuse_conn *fc = get_fuse_conn(&mp_fi->inode); 1420 struct super_block *sb; 1421 int err; 1422 1423 fm = kzalloc(sizeof(struct fuse_mount), GFP_KERNEL); 1424 if (!fm) 1425 return -ENOMEM; 1426 1427 fsc->s_fs_info = fm; 1428 sb = sget_fc(fsc, NULL, set_anon_super_fc); 1429 if (IS_ERR(sb)) { 1430 kfree(fm); 1431 return PTR_ERR(sb); 1432 } 1433 fm->fc = fuse_conn_get(fc); 1434 1435 /* Initialize superblock, making @mp_fi its root */ 1436 err = fuse_fill_super_submount(sb, mp_fi); 1437 if (err) { 1438 fuse_conn_put(fc); 1439 kfree(fm); 1440 sb->s_fs_info = NULL; 1441 deactivate_locked_super(sb); 1442 return err; 1443 } 1444 1445 down_write(&fc->killsb); 1446 list_add_tail(&fm->fc_entry, &fc->mounts); 1447 up_write(&fc->killsb); 1448 1449 sb->s_flags |= SB_ACTIVE; 1450 fsc->root = dget(sb->s_root); 1451 1452 return 0; 1453 } 1454 1455 static const struct fs_context_operations fuse_context_submount_ops = { 1456 .get_tree = fuse_get_tree_submount, 1457 }; 1458 1459 int fuse_init_fs_context_submount(struct fs_context *fsc) 1460 { 1461 fsc->ops = &fuse_context_submount_ops; 1462 return 0; 1463 } 1464 EXPORT_SYMBOL_GPL(fuse_init_fs_context_submount); 1465 1466 int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx) 1467 { 1468 struct fuse_dev *fud = NULL; 1469 struct fuse_mount *fm = get_fuse_mount_super(sb); 1470 struct fuse_conn *fc = fm->fc; 1471 struct inode *root; 1472 struct dentry *root_dentry; 1473 int err; 1474 1475 err = -EINVAL; 1476 if (sb->s_flags & SB_MANDLOCK) 1477 goto err; 1478 1479 rcu_assign_pointer(fc->curr_bucket, fuse_sync_bucket_alloc()); 1480 fuse_sb_defaults(sb); 1481 1482 if (ctx->is_bdev) { 1483 #ifdef CONFIG_BLOCK 1484 err = -EINVAL; 1485 if (!sb_set_blocksize(sb, ctx->blksize)) 1486 goto err; 1487 #endif 1488 } else { 1489 sb->s_blocksize = PAGE_SIZE; 1490 sb->s_blocksize_bits = PAGE_SHIFT; 1491 } 1492 1493 sb->s_subtype = ctx->subtype; 1494 ctx->subtype = NULL; 1495 if (IS_ENABLED(CONFIG_FUSE_DAX)) { 1496 err = fuse_dax_conn_alloc(fc, ctx->dax_dev); 1497 if (err) 1498 goto err; 1499 } 1500 1501 if (ctx->fudptr) { 1502 err = -ENOMEM; 1503 fud = fuse_dev_alloc_install(fc); 1504 if (!fud) 1505 goto err_free_dax; 1506 } 1507 1508 fc->dev = sb->s_dev; 1509 fm->sb = sb; 1510 err = fuse_bdi_init(fc, sb); 1511 if (err) 1512 goto err_dev_free; 1513 1514 /* Handle umasking inside the fuse code */ 1515 if (sb->s_flags & SB_POSIXACL) 1516 fc->dont_mask = 1; 1517 sb->s_flags |= SB_POSIXACL; 1518 1519 fc->default_permissions = ctx->default_permissions; 1520 fc->allow_other = ctx->allow_other; 1521 fc->user_id = ctx->user_id; 1522 fc->group_id = ctx->group_id; 1523 fc->legacy_opts_show = ctx->legacy_opts_show; 1524 fc->max_read = max_t(unsigned int, 4096, ctx->max_read); 1525 fc->destroy = ctx->destroy; 1526 fc->no_control = ctx->no_control; 1527 fc->no_force_umount = ctx->no_force_umount; 1528 1529 err = -ENOMEM; 1530 root = fuse_get_root_inode(sb, ctx->rootmode); 1531 sb->s_d_op = &fuse_root_dentry_operations; 1532 root_dentry = d_make_root(root); 1533 if (!root_dentry) 1534 goto err_dev_free; 1535 /* Root dentry doesn't have .d_revalidate */ 1536 sb->s_d_op = &fuse_dentry_operations; 1537 1538 mutex_lock(&fuse_mutex); 1539 err = -EINVAL; 1540 if (ctx->fudptr && *ctx->fudptr) 1541 goto err_unlock; 1542 1543 err = fuse_ctl_add_conn(fc); 1544 if (err) 1545 goto err_unlock; 1546 1547 list_add_tail(&fc->entry, &fuse_conn_list); 1548 sb->s_root = root_dentry; 1549 if (ctx->fudptr) 1550 *ctx->fudptr = fud; 1551 mutex_unlock(&fuse_mutex); 1552 return 0; 1553 1554 err_unlock: 1555 mutex_unlock(&fuse_mutex); 1556 dput(root_dentry); 1557 err_dev_free: 1558 if (fud) 1559 fuse_dev_free(fud); 1560 err_free_dax: 1561 if (IS_ENABLED(CONFIG_FUSE_DAX)) 1562 fuse_dax_conn_free(fc); 1563 err: 1564 return err; 1565 } 1566 EXPORT_SYMBOL_GPL(fuse_fill_super_common); 1567 1568 static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc) 1569 { 1570 struct fuse_fs_context *ctx = fsc->fs_private; 1571 int err; 1572 struct fuse_conn *fc; 1573 struct fuse_mount *fm; 1574 1575 if (!ctx->file || !ctx->rootmode_present || 1576 !ctx->user_id_present || !ctx->group_id_present) 1577 return -EINVAL; 1578 1579 /* 1580 * Require mount to happen from the same user namespace which 1581 * opened /dev/fuse to prevent potential attacks. 1582 */ 1583 err = -EINVAL; 1584 if ((ctx->file->f_op != &fuse_dev_operations) || 1585 (ctx->file->f_cred->user_ns != sb->s_user_ns)) 1586 goto err; 1587 ctx->fudptr = &ctx->file->private_data; 1588 1589 fc = kmalloc(sizeof(*fc), GFP_KERNEL); 1590 err = -ENOMEM; 1591 if (!fc) 1592 goto err; 1593 1594 fm = kzalloc(sizeof(*fm), GFP_KERNEL); 1595 if (!fm) { 1596 kfree(fc); 1597 goto err; 1598 } 1599 1600 fuse_conn_init(fc, fm, sb->s_user_ns, &fuse_dev_fiq_ops, NULL); 1601 fc->release = fuse_free_conn; 1602 1603 sb->s_fs_info = fm; 1604 1605 err = fuse_fill_super_common(sb, ctx); 1606 if (err) 1607 goto err_put_conn; 1608 /* file->private_data shall be visible on all CPUs after this */ 1609 smp_mb(); 1610 fuse_send_init(get_fuse_mount_super(sb)); 1611 return 0; 1612 1613 err_put_conn: 1614 fuse_conn_put(fc); 1615 kfree(fm); 1616 sb->s_fs_info = NULL; 1617 err: 1618 return err; 1619 } 1620 1621 /* 1622 * This is the path where user supplied an already initialized fuse dev. In 1623 * this case never create a new super if the old one is gone. 1624 */ 1625 static int fuse_set_no_super(struct super_block *sb, struct fs_context *fsc) 1626 { 1627 return -ENOTCONN; 1628 } 1629 1630 static int fuse_test_super(struct super_block *sb, struct fs_context *fsc) 1631 { 1632 1633 return fsc->sget_key == get_fuse_conn_super(sb); 1634 } 1635 1636 static int fuse_get_tree(struct fs_context *fsc) 1637 { 1638 struct fuse_fs_context *ctx = fsc->fs_private; 1639 struct fuse_dev *fud; 1640 struct super_block *sb; 1641 int err; 1642 1643 if (ctx->fd_present) 1644 ctx->file = fget(ctx->fd); 1645 1646 if (IS_ENABLED(CONFIG_BLOCK) && ctx->is_bdev) { 1647 err = get_tree_bdev(fsc, fuse_fill_super); 1648 goto out_fput; 1649 } 1650 /* 1651 * While block dev mount can be initialized with a dummy device fd 1652 * (found by device name), normal fuse mounts can't 1653 */ 1654 if (!ctx->file) 1655 return -EINVAL; 1656 1657 /* 1658 * Allow creating a fuse mount with an already initialized fuse 1659 * connection 1660 */ 1661 fud = READ_ONCE(ctx->file->private_data); 1662 if (ctx->file->f_op == &fuse_dev_operations && fud) { 1663 fsc->sget_key = fud->fc; 1664 sb = sget_fc(fsc, fuse_test_super, fuse_set_no_super); 1665 err = PTR_ERR_OR_ZERO(sb); 1666 if (!IS_ERR(sb)) 1667 fsc->root = dget(sb->s_root); 1668 } else { 1669 err = get_tree_nodev(fsc, fuse_fill_super); 1670 } 1671 out_fput: 1672 if (ctx->file) 1673 fput(ctx->file); 1674 return err; 1675 } 1676 1677 static const struct fs_context_operations fuse_context_ops = { 1678 .free = fuse_free_fsc, 1679 .parse_param = fuse_parse_param, 1680 .reconfigure = fuse_reconfigure, 1681 .get_tree = fuse_get_tree, 1682 }; 1683 1684 /* 1685 * Set up the filesystem mount context. 1686 */ 1687 static int fuse_init_fs_context(struct fs_context *fsc) 1688 { 1689 struct fuse_fs_context *ctx; 1690 1691 ctx = kzalloc(sizeof(struct fuse_fs_context), GFP_KERNEL); 1692 if (!ctx) 1693 return -ENOMEM; 1694 1695 ctx->max_read = ~0; 1696 ctx->blksize = FUSE_DEFAULT_BLKSIZE; 1697 ctx->legacy_opts_show = true; 1698 1699 #ifdef CONFIG_BLOCK 1700 if (fsc->fs_type == &fuseblk_fs_type) { 1701 ctx->is_bdev = true; 1702 ctx->destroy = true; 1703 } 1704 #endif 1705 1706 fsc->fs_private = ctx; 1707 fsc->ops = &fuse_context_ops; 1708 return 0; 1709 } 1710 1711 bool fuse_mount_remove(struct fuse_mount *fm) 1712 { 1713 struct fuse_conn *fc = fm->fc; 1714 bool last = false; 1715 1716 down_write(&fc->killsb); 1717 list_del_init(&fm->fc_entry); 1718 if (list_empty(&fc->mounts)) 1719 last = true; 1720 up_write(&fc->killsb); 1721 1722 return last; 1723 } 1724 EXPORT_SYMBOL_GPL(fuse_mount_remove); 1725 1726 void fuse_conn_destroy(struct fuse_mount *fm) 1727 { 1728 struct fuse_conn *fc = fm->fc; 1729 1730 if (fc->destroy) 1731 fuse_send_destroy(fm); 1732 1733 fuse_abort_conn(fc); 1734 fuse_wait_aborted(fc); 1735 1736 if (!list_empty(&fc->entry)) { 1737 mutex_lock(&fuse_mutex); 1738 list_del(&fc->entry); 1739 fuse_ctl_remove_conn(fc); 1740 mutex_unlock(&fuse_mutex); 1741 } 1742 } 1743 EXPORT_SYMBOL_GPL(fuse_conn_destroy); 1744 1745 static void fuse_sb_destroy(struct super_block *sb) 1746 { 1747 struct fuse_mount *fm = get_fuse_mount_super(sb); 1748 bool last; 1749 1750 if (fm) { 1751 last = fuse_mount_remove(fm); 1752 if (last) 1753 fuse_conn_destroy(fm); 1754 } 1755 } 1756 1757 static void fuse_kill_sb_anon(struct super_block *sb) 1758 { 1759 fuse_sb_destroy(sb); 1760 kill_anon_super(sb); 1761 } 1762 1763 static struct file_system_type fuse_fs_type = { 1764 .owner = THIS_MODULE, 1765 .name = "fuse", 1766 .fs_flags = FS_HAS_SUBTYPE | FS_USERNS_MOUNT, 1767 .init_fs_context = fuse_init_fs_context, 1768 .parameters = fuse_fs_parameters, 1769 .kill_sb = fuse_kill_sb_anon, 1770 }; 1771 MODULE_ALIAS_FS("fuse"); 1772 1773 #ifdef CONFIG_BLOCK 1774 static void fuse_kill_sb_blk(struct super_block *sb) 1775 { 1776 fuse_sb_destroy(sb); 1777 kill_block_super(sb); 1778 } 1779 1780 static struct file_system_type fuseblk_fs_type = { 1781 .owner = THIS_MODULE, 1782 .name = "fuseblk", 1783 .init_fs_context = fuse_init_fs_context, 1784 .parameters = fuse_fs_parameters, 1785 .kill_sb = fuse_kill_sb_blk, 1786 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE, 1787 }; 1788 MODULE_ALIAS_FS("fuseblk"); 1789 1790 static inline int register_fuseblk(void) 1791 { 1792 return register_filesystem(&fuseblk_fs_type); 1793 } 1794 1795 static inline void unregister_fuseblk(void) 1796 { 1797 unregister_filesystem(&fuseblk_fs_type); 1798 } 1799 #else 1800 static inline int register_fuseblk(void) 1801 { 1802 return 0; 1803 } 1804 1805 static inline void unregister_fuseblk(void) 1806 { 1807 } 1808 #endif 1809 1810 static void fuse_inode_init_once(void *foo) 1811 { 1812 struct inode *inode = foo; 1813 1814 inode_init_once(inode); 1815 } 1816 1817 static int __init fuse_fs_init(void) 1818 { 1819 int err; 1820 1821 fuse_inode_cachep = kmem_cache_create("fuse_inode", 1822 sizeof(struct fuse_inode), 0, 1823 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT, 1824 fuse_inode_init_once); 1825 err = -ENOMEM; 1826 if (!fuse_inode_cachep) 1827 goto out; 1828 1829 err = register_fuseblk(); 1830 if (err) 1831 goto out2; 1832 1833 err = register_filesystem(&fuse_fs_type); 1834 if (err) 1835 goto out3; 1836 1837 return 0; 1838 1839 out3: 1840 unregister_fuseblk(); 1841 out2: 1842 kmem_cache_destroy(fuse_inode_cachep); 1843 out: 1844 return err; 1845 } 1846 1847 static void fuse_fs_cleanup(void) 1848 { 1849 unregister_filesystem(&fuse_fs_type); 1850 unregister_fuseblk(); 1851 1852 /* 1853 * Make sure all delayed rcu free inodes are flushed before we 1854 * destroy cache. 1855 */ 1856 rcu_barrier(); 1857 kmem_cache_destroy(fuse_inode_cachep); 1858 } 1859 1860 static struct kobject *fuse_kobj; 1861 1862 static int fuse_sysfs_init(void) 1863 { 1864 int err; 1865 1866 fuse_kobj = kobject_create_and_add("fuse", fs_kobj); 1867 if (!fuse_kobj) { 1868 err = -ENOMEM; 1869 goto out_err; 1870 } 1871 1872 err = sysfs_create_mount_point(fuse_kobj, "connections"); 1873 if (err) 1874 goto out_fuse_unregister; 1875 1876 return 0; 1877 1878 out_fuse_unregister: 1879 kobject_put(fuse_kobj); 1880 out_err: 1881 return err; 1882 } 1883 1884 static void fuse_sysfs_cleanup(void) 1885 { 1886 sysfs_remove_mount_point(fuse_kobj, "connections"); 1887 kobject_put(fuse_kobj); 1888 } 1889 1890 static int __init fuse_init(void) 1891 { 1892 int res; 1893 1894 pr_info("init (API version %i.%i)\n", 1895 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION); 1896 1897 INIT_LIST_HEAD(&fuse_conn_list); 1898 res = fuse_fs_init(); 1899 if (res) 1900 goto err; 1901 1902 res = fuse_dev_init(); 1903 if (res) 1904 goto err_fs_cleanup; 1905 1906 res = fuse_sysfs_init(); 1907 if (res) 1908 goto err_dev_cleanup; 1909 1910 res = fuse_ctl_init(); 1911 if (res) 1912 goto err_sysfs_cleanup; 1913 1914 sanitize_global_limit(&max_user_bgreq); 1915 sanitize_global_limit(&max_user_congthresh); 1916 1917 return 0; 1918 1919 err_sysfs_cleanup: 1920 fuse_sysfs_cleanup(); 1921 err_dev_cleanup: 1922 fuse_dev_cleanup(); 1923 err_fs_cleanup: 1924 fuse_fs_cleanup(); 1925 err: 1926 return res; 1927 } 1928 1929 static void __exit fuse_exit(void) 1930 { 1931 pr_debug("exit\n"); 1932 1933 fuse_ctl_cleanup(); 1934 fuse_sysfs_cleanup(); 1935 fuse_fs_cleanup(); 1936 fuse_dev_cleanup(); 1937 } 1938 1939 module_init(fuse_init); 1940 module_exit(fuse_exit); 1941