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 *fc) 141 { 142 struct super_block *sb = fc->root->d_sb; 143 144 sync_filesystem(sb); 145 if (fc->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 int fuse_sync_fs(struct super_block *sb, int wait) 509 { 510 struct fuse_mount *fm = get_fuse_mount_super(sb); 511 struct fuse_conn *fc = fm->fc; 512 struct fuse_syncfs_in inarg; 513 FUSE_ARGS(args); 514 int err; 515 516 /* 517 * Userspace cannot handle the wait == 0 case. Avoid a 518 * gratuitous roundtrip. 519 */ 520 if (!wait) 521 return 0; 522 523 /* The filesystem is being unmounted. Nothing to do. */ 524 if (!sb->s_root) 525 return 0; 526 527 if (!fc->sync_fs) 528 return 0; 529 530 memset(&inarg, 0, sizeof(inarg)); 531 args.in_numargs = 1; 532 args.in_args[0].size = sizeof(inarg); 533 args.in_args[0].value = &inarg; 534 args.opcode = FUSE_SYNCFS; 535 args.nodeid = get_node_id(sb->s_root->d_inode); 536 args.out_numargs = 0; 537 538 err = fuse_simple_request(fm, &args); 539 if (err == -ENOSYS) { 540 fc->sync_fs = 0; 541 err = 0; 542 } 543 544 return err; 545 } 546 547 enum { 548 OPT_SOURCE, 549 OPT_SUBTYPE, 550 OPT_FD, 551 OPT_ROOTMODE, 552 OPT_USER_ID, 553 OPT_GROUP_ID, 554 OPT_DEFAULT_PERMISSIONS, 555 OPT_ALLOW_OTHER, 556 OPT_MAX_READ, 557 OPT_BLKSIZE, 558 OPT_ERR 559 }; 560 561 static const struct fs_parameter_spec fuse_fs_parameters[] = { 562 fsparam_string ("source", OPT_SOURCE), 563 fsparam_u32 ("fd", OPT_FD), 564 fsparam_u32oct ("rootmode", OPT_ROOTMODE), 565 fsparam_u32 ("user_id", OPT_USER_ID), 566 fsparam_u32 ("group_id", OPT_GROUP_ID), 567 fsparam_flag ("default_permissions", OPT_DEFAULT_PERMISSIONS), 568 fsparam_flag ("allow_other", OPT_ALLOW_OTHER), 569 fsparam_u32 ("max_read", OPT_MAX_READ), 570 fsparam_u32 ("blksize", OPT_BLKSIZE), 571 fsparam_string ("subtype", OPT_SUBTYPE), 572 {} 573 }; 574 575 static int fuse_parse_param(struct fs_context *fc, struct fs_parameter *param) 576 { 577 struct fs_parse_result result; 578 struct fuse_fs_context *ctx = fc->fs_private; 579 int opt; 580 581 if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE) { 582 /* 583 * Ignore options coming from mount(MS_REMOUNT) for backward 584 * compatibility. 585 */ 586 if (fc->oldapi) 587 return 0; 588 589 return invalfc(fc, "No changes allowed in reconfigure"); 590 } 591 592 opt = fs_parse(fc, fuse_fs_parameters, param, &result); 593 if (opt < 0) 594 return opt; 595 596 switch (opt) { 597 case OPT_SOURCE: 598 if (fc->source) 599 return invalfc(fc, "Multiple sources specified"); 600 fc->source = param->string; 601 param->string = NULL; 602 break; 603 604 case OPT_SUBTYPE: 605 if (ctx->subtype) 606 return invalfc(fc, "Multiple subtypes specified"); 607 ctx->subtype = param->string; 608 param->string = NULL; 609 return 0; 610 611 case OPT_FD: 612 ctx->fd = result.uint_32; 613 ctx->fd_present = true; 614 break; 615 616 case OPT_ROOTMODE: 617 if (!fuse_valid_type(result.uint_32)) 618 return invalfc(fc, "Invalid rootmode"); 619 ctx->rootmode = result.uint_32; 620 ctx->rootmode_present = true; 621 break; 622 623 case OPT_USER_ID: 624 ctx->user_id = make_kuid(fc->user_ns, result.uint_32); 625 if (!uid_valid(ctx->user_id)) 626 return invalfc(fc, "Invalid user_id"); 627 ctx->user_id_present = true; 628 break; 629 630 case OPT_GROUP_ID: 631 ctx->group_id = make_kgid(fc->user_ns, result.uint_32); 632 if (!gid_valid(ctx->group_id)) 633 return invalfc(fc, "Invalid group_id"); 634 ctx->group_id_present = true; 635 break; 636 637 case OPT_DEFAULT_PERMISSIONS: 638 ctx->default_permissions = true; 639 break; 640 641 case OPT_ALLOW_OTHER: 642 ctx->allow_other = true; 643 break; 644 645 case OPT_MAX_READ: 646 ctx->max_read = result.uint_32; 647 break; 648 649 case OPT_BLKSIZE: 650 if (!ctx->is_bdev) 651 return invalfc(fc, "blksize only supported for fuseblk"); 652 ctx->blksize = result.uint_32; 653 break; 654 655 default: 656 return -EINVAL; 657 } 658 659 return 0; 660 } 661 662 static void fuse_free_fc(struct fs_context *fc) 663 { 664 struct fuse_fs_context *ctx = fc->fs_private; 665 666 if (ctx) { 667 kfree(ctx->subtype); 668 kfree(ctx); 669 } 670 } 671 672 static int fuse_show_options(struct seq_file *m, struct dentry *root) 673 { 674 struct super_block *sb = root->d_sb; 675 struct fuse_conn *fc = get_fuse_conn_super(sb); 676 677 if (fc->legacy_opts_show) { 678 seq_printf(m, ",user_id=%u", 679 from_kuid_munged(fc->user_ns, fc->user_id)); 680 seq_printf(m, ",group_id=%u", 681 from_kgid_munged(fc->user_ns, fc->group_id)); 682 if (fc->default_permissions) 683 seq_puts(m, ",default_permissions"); 684 if (fc->allow_other) 685 seq_puts(m, ",allow_other"); 686 if (fc->max_read != ~0) 687 seq_printf(m, ",max_read=%u", fc->max_read); 688 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE) 689 seq_printf(m, ",blksize=%lu", sb->s_blocksize); 690 } 691 #ifdef CONFIG_FUSE_DAX 692 if (fc->dax) 693 seq_puts(m, ",dax"); 694 #endif 695 696 return 0; 697 } 698 699 static void fuse_iqueue_init(struct fuse_iqueue *fiq, 700 const struct fuse_iqueue_ops *ops, 701 void *priv) 702 { 703 memset(fiq, 0, sizeof(struct fuse_iqueue)); 704 spin_lock_init(&fiq->lock); 705 init_waitqueue_head(&fiq->waitq); 706 INIT_LIST_HEAD(&fiq->pending); 707 INIT_LIST_HEAD(&fiq->interrupts); 708 fiq->forget_list_tail = &fiq->forget_list_head; 709 fiq->connected = 1; 710 fiq->ops = ops; 711 fiq->priv = priv; 712 } 713 714 static void fuse_pqueue_init(struct fuse_pqueue *fpq) 715 { 716 unsigned int i; 717 718 spin_lock_init(&fpq->lock); 719 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) 720 INIT_LIST_HEAD(&fpq->processing[i]); 721 INIT_LIST_HEAD(&fpq->io); 722 fpq->connected = 1; 723 } 724 725 void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm, 726 struct user_namespace *user_ns, 727 const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv) 728 { 729 memset(fc, 0, sizeof(*fc)); 730 spin_lock_init(&fc->lock); 731 spin_lock_init(&fc->bg_lock); 732 init_rwsem(&fc->killsb); 733 refcount_set(&fc->count, 1); 734 atomic_set(&fc->dev_count, 1); 735 init_waitqueue_head(&fc->blocked_waitq); 736 fuse_iqueue_init(&fc->iq, fiq_ops, fiq_priv); 737 INIT_LIST_HEAD(&fc->bg_queue); 738 INIT_LIST_HEAD(&fc->entry); 739 INIT_LIST_HEAD(&fc->devices); 740 atomic_set(&fc->num_waiting, 0); 741 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND; 742 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD; 743 atomic64_set(&fc->khctr, 0); 744 fc->polled_files = RB_ROOT; 745 fc->blocked = 0; 746 fc->initialized = 0; 747 fc->connected = 1; 748 atomic64_set(&fc->attr_version, 1); 749 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key)); 750 fc->pid_ns = get_pid_ns(task_active_pid_ns(current)); 751 fc->user_ns = get_user_ns(user_ns); 752 fc->max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ; 753 fc->max_pages_limit = FUSE_MAX_MAX_PAGES; 754 755 INIT_LIST_HEAD(&fc->mounts); 756 list_add(&fm->fc_entry, &fc->mounts); 757 fm->fc = fc; 758 } 759 EXPORT_SYMBOL_GPL(fuse_conn_init); 760 761 void fuse_conn_put(struct fuse_conn *fc) 762 { 763 if (refcount_dec_and_test(&fc->count)) { 764 struct fuse_iqueue *fiq = &fc->iq; 765 766 if (IS_ENABLED(CONFIG_FUSE_DAX)) 767 fuse_dax_conn_free(fc); 768 if (fiq->ops->release) 769 fiq->ops->release(fiq); 770 put_pid_ns(fc->pid_ns); 771 put_user_ns(fc->user_ns); 772 fc->release(fc); 773 } 774 } 775 EXPORT_SYMBOL_GPL(fuse_conn_put); 776 777 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc) 778 { 779 refcount_inc(&fc->count); 780 return fc; 781 } 782 EXPORT_SYMBOL_GPL(fuse_conn_get); 783 784 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode) 785 { 786 struct fuse_attr attr; 787 memset(&attr, 0, sizeof(attr)); 788 789 attr.mode = mode; 790 attr.ino = FUSE_ROOT_ID; 791 attr.nlink = 1; 792 return fuse_iget(sb, 1, 0, &attr, 0, 0); 793 } 794 795 struct fuse_inode_handle { 796 u64 nodeid; 797 u32 generation; 798 }; 799 800 static struct dentry *fuse_get_dentry(struct super_block *sb, 801 struct fuse_inode_handle *handle) 802 { 803 struct fuse_conn *fc = get_fuse_conn_super(sb); 804 struct inode *inode; 805 struct dentry *entry; 806 int err = -ESTALE; 807 808 if (handle->nodeid == 0) 809 goto out_err; 810 811 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid); 812 if (!inode) { 813 struct fuse_entry_out outarg; 814 const struct qstr name = QSTR_INIT(".", 1); 815 816 if (!fc->export_support) 817 goto out_err; 818 819 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg, 820 &inode); 821 if (err && err != -ENOENT) 822 goto out_err; 823 if (err || !inode) { 824 err = -ESTALE; 825 goto out_err; 826 } 827 err = -EIO; 828 if (get_node_id(inode) != handle->nodeid) 829 goto out_iput; 830 } 831 err = -ESTALE; 832 if (inode->i_generation != handle->generation) 833 goto out_iput; 834 835 entry = d_obtain_alias(inode); 836 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID) 837 fuse_invalidate_entry_cache(entry); 838 839 return entry; 840 841 out_iput: 842 iput(inode); 843 out_err: 844 return ERR_PTR(err); 845 } 846 847 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len, 848 struct inode *parent) 849 { 850 int len = parent ? 6 : 3; 851 u64 nodeid; 852 u32 generation; 853 854 if (*max_len < len) { 855 *max_len = len; 856 return FILEID_INVALID; 857 } 858 859 nodeid = get_fuse_inode(inode)->nodeid; 860 generation = inode->i_generation; 861 862 fh[0] = (u32)(nodeid >> 32); 863 fh[1] = (u32)(nodeid & 0xffffffff); 864 fh[2] = generation; 865 866 if (parent) { 867 nodeid = get_fuse_inode(parent)->nodeid; 868 generation = parent->i_generation; 869 870 fh[3] = (u32)(nodeid >> 32); 871 fh[4] = (u32)(nodeid & 0xffffffff); 872 fh[5] = generation; 873 } 874 875 *max_len = len; 876 return parent ? 0x82 : 0x81; 877 } 878 879 static struct dentry *fuse_fh_to_dentry(struct super_block *sb, 880 struct fid *fid, int fh_len, int fh_type) 881 { 882 struct fuse_inode_handle handle; 883 884 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3) 885 return NULL; 886 887 handle.nodeid = (u64) fid->raw[0] << 32; 888 handle.nodeid |= (u64) fid->raw[1]; 889 handle.generation = fid->raw[2]; 890 return fuse_get_dentry(sb, &handle); 891 } 892 893 static struct dentry *fuse_fh_to_parent(struct super_block *sb, 894 struct fid *fid, int fh_len, int fh_type) 895 { 896 struct fuse_inode_handle parent; 897 898 if (fh_type != 0x82 || fh_len < 6) 899 return NULL; 900 901 parent.nodeid = (u64) fid->raw[3] << 32; 902 parent.nodeid |= (u64) fid->raw[4]; 903 parent.generation = fid->raw[5]; 904 return fuse_get_dentry(sb, &parent); 905 } 906 907 static struct dentry *fuse_get_parent(struct dentry *child) 908 { 909 struct inode *child_inode = d_inode(child); 910 struct fuse_conn *fc = get_fuse_conn(child_inode); 911 struct inode *inode; 912 struct dentry *parent; 913 struct fuse_entry_out outarg; 914 int err; 915 916 if (!fc->export_support) 917 return ERR_PTR(-ESTALE); 918 919 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode), 920 &dotdot_name, &outarg, &inode); 921 if (err) { 922 if (err == -ENOENT) 923 return ERR_PTR(-ESTALE); 924 return ERR_PTR(err); 925 } 926 927 parent = d_obtain_alias(inode); 928 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID) 929 fuse_invalidate_entry_cache(parent); 930 931 return parent; 932 } 933 934 static const struct export_operations fuse_export_operations = { 935 .fh_to_dentry = fuse_fh_to_dentry, 936 .fh_to_parent = fuse_fh_to_parent, 937 .encode_fh = fuse_encode_fh, 938 .get_parent = fuse_get_parent, 939 }; 940 941 static const struct super_operations fuse_super_operations = { 942 .alloc_inode = fuse_alloc_inode, 943 .free_inode = fuse_free_inode, 944 .evict_inode = fuse_evict_inode, 945 .write_inode = fuse_write_inode, 946 .drop_inode = generic_delete_inode, 947 .put_super = fuse_put_super, 948 .umount_begin = fuse_umount_begin, 949 .statfs = fuse_statfs, 950 .sync_fs = fuse_sync_fs, 951 .show_options = fuse_show_options, 952 }; 953 954 static void sanitize_global_limit(unsigned *limit) 955 { 956 /* 957 * The default maximum number of async requests is calculated to consume 958 * 1/2^13 of the total memory, assuming 392 bytes per request. 959 */ 960 if (*limit == 0) 961 *limit = ((totalram_pages() << PAGE_SHIFT) >> 13) / 392; 962 963 if (*limit >= 1 << 16) 964 *limit = (1 << 16) - 1; 965 } 966 967 static int set_global_limit(const char *val, const struct kernel_param *kp) 968 { 969 int rv; 970 971 rv = param_set_uint(val, kp); 972 if (rv) 973 return rv; 974 975 sanitize_global_limit((unsigned *)kp->arg); 976 977 return 0; 978 } 979 980 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg) 981 { 982 int cap_sys_admin = capable(CAP_SYS_ADMIN); 983 984 if (arg->minor < 13) 985 return; 986 987 sanitize_global_limit(&max_user_bgreq); 988 sanitize_global_limit(&max_user_congthresh); 989 990 spin_lock(&fc->bg_lock); 991 if (arg->max_background) { 992 fc->max_background = arg->max_background; 993 994 if (!cap_sys_admin && fc->max_background > max_user_bgreq) 995 fc->max_background = max_user_bgreq; 996 } 997 if (arg->congestion_threshold) { 998 fc->congestion_threshold = arg->congestion_threshold; 999 1000 if (!cap_sys_admin && 1001 fc->congestion_threshold > max_user_congthresh) 1002 fc->congestion_threshold = max_user_congthresh; 1003 } 1004 spin_unlock(&fc->bg_lock); 1005 } 1006 1007 struct fuse_init_args { 1008 struct fuse_args args; 1009 struct fuse_init_in in; 1010 struct fuse_init_out out; 1011 }; 1012 1013 static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args, 1014 int error) 1015 { 1016 struct fuse_conn *fc = fm->fc; 1017 struct fuse_init_args *ia = container_of(args, typeof(*ia), args); 1018 struct fuse_init_out *arg = &ia->out; 1019 bool ok = true; 1020 1021 if (error || arg->major != FUSE_KERNEL_VERSION) 1022 ok = false; 1023 else { 1024 unsigned long ra_pages; 1025 1026 process_init_limits(fc, arg); 1027 1028 if (arg->minor >= 6) { 1029 ra_pages = arg->max_readahead / PAGE_SIZE; 1030 if (arg->flags & FUSE_ASYNC_READ) 1031 fc->async_read = 1; 1032 if (!(arg->flags & FUSE_POSIX_LOCKS)) 1033 fc->no_lock = 1; 1034 if (arg->minor >= 17) { 1035 if (!(arg->flags & FUSE_FLOCK_LOCKS)) 1036 fc->no_flock = 1; 1037 } else { 1038 if (!(arg->flags & FUSE_POSIX_LOCKS)) 1039 fc->no_flock = 1; 1040 } 1041 if (arg->flags & FUSE_ATOMIC_O_TRUNC) 1042 fc->atomic_o_trunc = 1; 1043 if (arg->minor >= 9) { 1044 /* LOOKUP has dependency on proto version */ 1045 if (arg->flags & FUSE_EXPORT_SUPPORT) 1046 fc->export_support = 1; 1047 } 1048 if (arg->flags & FUSE_BIG_WRITES) 1049 fc->big_writes = 1; 1050 if (arg->flags & FUSE_DONT_MASK) 1051 fc->dont_mask = 1; 1052 if (arg->flags & FUSE_AUTO_INVAL_DATA) 1053 fc->auto_inval_data = 1; 1054 else if (arg->flags & FUSE_EXPLICIT_INVAL_DATA) 1055 fc->explicit_inval_data = 1; 1056 if (arg->flags & FUSE_DO_READDIRPLUS) { 1057 fc->do_readdirplus = 1; 1058 if (arg->flags & FUSE_READDIRPLUS_AUTO) 1059 fc->readdirplus_auto = 1; 1060 } 1061 if (arg->flags & FUSE_ASYNC_DIO) 1062 fc->async_dio = 1; 1063 if (arg->flags & FUSE_WRITEBACK_CACHE) 1064 fc->writeback_cache = 1; 1065 if (arg->flags & FUSE_PARALLEL_DIROPS) 1066 fc->parallel_dirops = 1; 1067 if (arg->flags & FUSE_HANDLE_KILLPRIV) 1068 fc->handle_killpriv = 1; 1069 if (arg->time_gran && arg->time_gran <= 1000000000) 1070 fm->sb->s_time_gran = arg->time_gran; 1071 if ((arg->flags & FUSE_POSIX_ACL)) { 1072 fc->default_permissions = 1; 1073 fc->posix_acl = 1; 1074 fm->sb->s_xattr = fuse_acl_xattr_handlers; 1075 } 1076 if (arg->flags & FUSE_CACHE_SYMLINKS) 1077 fc->cache_symlinks = 1; 1078 if (arg->flags & FUSE_ABORT_ERROR) 1079 fc->abort_err = 1; 1080 if (arg->flags & FUSE_MAX_PAGES) { 1081 fc->max_pages = 1082 min_t(unsigned int, fc->max_pages_limit, 1083 max_t(unsigned int, arg->max_pages, 1)); 1084 } 1085 if (IS_ENABLED(CONFIG_FUSE_DAX) && 1086 arg->flags & FUSE_MAP_ALIGNMENT && 1087 !fuse_dax_check_alignment(fc, arg->map_alignment)) { 1088 ok = false; 1089 } 1090 if (arg->flags & FUSE_HANDLE_KILLPRIV_V2) { 1091 fc->handle_killpriv_v2 = 1; 1092 fm->sb->s_flags |= SB_NOSEC; 1093 } 1094 if (arg->flags & FUSE_SETXATTR_EXT) 1095 fc->setxattr_ext = 1; 1096 } else { 1097 ra_pages = fc->max_read / PAGE_SIZE; 1098 fc->no_lock = 1; 1099 fc->no_flock = 1; 1100 } 1101 1102 fm->sb->s_bdi->ra_pages = 1103 min(fm->sb->s_bdi->ra_pages, ra_pages); 1104 fc->minor = arg->minor; 1105 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write; 1106 fc->max_write = max_t(unsigned, 4096, fc->max_write); 1107 fc->conn_init = 1; 1108 } 1109 kfree(ia); 1110 1111 if (!ok) { 1112 fc->conn_init = 0; 1113 fc->conn_error = 1; 1114 } 1115 1116 fuse_set_initialized(fc); 1117 wake_up_all(&fc->blocked_waitq); 1118 } 1119 1120 void fuse_send_init(struct fuse_mount *fm) 1121 { 1122 struct fuse_init_args *ia; 1123 1124 ia = kzalloc(sizeof(*ia), GFP_KERNEL | __GFP_NOFAIL); 1125 1126 ia->in.major = FUSE_KERNEL_VERSION; 1127 ia->in.minor = FUSE_KERNEL_MINOR_VERSION; 1128 ia->in.max_readahead = fm->sb->s_bdi->ra_pages * PAGE_SIZE; 1129 ia->in.flags |= 1130 FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC | 1131 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK | 1132 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ | 1133 FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA | 1134 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO | 1135 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT | 1136 FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL | 1137 FUSE_ABORT_ERROR | FUSE_MAX_PAGES | FUSE_CACHE_SYMLINKS | 1138 FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA | 1139 FUSE_HANDLE_KILLPRIV_V2 | FUSE_SETXATTR_EXT; 1140 #ifdef CONFIG_FUSE_DAX 1141 if (fm->fc->dax) 1142 ia->in.flags |= FUSE_MAP_ALIGNMENT; 1143 #endif 1144 if (fm->fc->auto_submounts) 1145 ia->in.flags |= FUSE_SUBMOUNTS; 1146 1147 ia->args.opcode = FUSE_INIT; 1148 ia->args.in_numargs = 1; 1149 ia->args.in_args[0].size = sizeof(ia->in); 1150 ia->args.in_args[0].value = &ia->in; 1151 ia->args.out_numargs = 1; 1152 /* Variable length argument used for backward compatibility 1153 with interface version < 7.5. Rest of init_out is zeroed 1154 by do_get_request(), so a short reply is not a problem */ 1155 ia->args.out_argvar = true; 1156 ia->args.out_args[0].size = sizeof(ia->out); 1157 ia->args.out_args[0].value = &ia->out; 1158 ia->args.force = true; 1159 ia->args.nocreds = true; 1160 ia->args.end = process_init_reply; 1161 1162 if (fuse_simple_background(fm, &ia->args, GFP_KERNEL) != 0) 1163 process_init_reply(fm, &ia->args, -ENOTCONN); 1164 } 1165 EXPORT_SYMBOL_GPL(fuse_send_init); 1166 1167 void fuse_free_conn(struct fuse_conn *fc) 1168 { 1169 WARN_ON(!list_empty(&fc->devices)); 1170 kfree_rcu(fc, rcu); 1171 } 1172 EXPORT_SYMBOL_GPL(fuse_free_conn); 1173 1174 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb) 1175 { 1176 int err; 1177 char *suffix = ""; 1178 1179 if (sb->s_bdev) { 1180 suffix = "-fuseblk"; 1181 /* 1182 * sb->s_bdi points to blkdev's bdi however we want to redirect 1183 * it to our private bdi... 1184 */ 1185 bdi_put(sb->s_bdi); 1186 sb->s_bdi = &noop_backing_dev_info; 1187 } 1188 err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev), 1189 MINOR(fc->dev), suffix); 1190 if (err) 1191 return err; 1192 1193 /* fuse does it's own writeback accounting */ 1194 sb->s_bdi->capabilities &= ~BDI_CAP_WRITEBACK_ACCT; 1195 sb->s_bdi->capabilities |= BDI_CAP_STRICTLIMIT; 1196 1197 /* 1198 * For a single fuse filesystem use max 1% of dirty + 1199 * writeback threshold. 1200 * 1201 * This gives about 1M of write buffer for memory maps on a 1202 * machine with 1G and 10% dirty_ratio, which should be more 1203 * than enough. 1204 * 1205 * Privileged users can raise it by writing to 1206 * 1207 * /sys/class/bdi/<bdi>/max_ratio 1208 */ 1209 bdi_set_max_ratio(sb->s_bdi, 1); 1210 1211 return 0; 1212 } 1213 1214 struct fuse_dev *fuse_dev_alloc(void) 1215 { 1216 struct fuse_dev *fud; 1217 struct list_head *pq; 1218 1219 fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL); 1220 if (!fud) 1221 return NULL; 1222 1223 pq = kcalloc(FUSE_PQ_HASH_SIZE, sizeof(struct list_head), GFP_KERNEL); 1224 if (!pq) { 1225 kfree(fud); 1226 return NULL; 1227 } 1228 1229 fud->pq.processing = pq; 1230 fuse_pqueue_init(&fud->pq); 1231 1232 return fud; 1233 } 1234 EXPORT_SYMBOL_GPL(fuse_dev_alloc); 1235 1236 void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc) 1237 { 1238 fud->fc = fuse_conn_get(fc); 1239 spin_lock(&fc->lock); 1240 list_add_tail(&fud->entry, &fc->devices); 1241 spin_unlock(&fc->lock); 1242 } 1243 EXPORT_SYMBOL_GPL(fuse_dev_install); 1244 1245 struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc) 1246 { 1247 struct fuse_dev *fud; 1248 1249 fud = fuse_dev_alloc(); 1250 if (!fud) 1251 return NULL; 1252 1253 fuse_dev_install(fud, fc); 1254 return fud; 1255 } 1256 EXPORT_SYMBOL_GPL(fuse_dev_alloc_install); 1257 1258 void fuse_dev_free(struct fuse_dev *fud) 1259 { 1260 struct fuse_conn *fc = fud->fc; 1261 1262 if (fc) { 1263 spin_lock(&fc->lock); 1264 list_del(&fud->entry); 1265 spin_unlock(&fc->lock); 1266 1267 fuse_conn_put(fc); 1268 } 1269 kfree(fud->pq.processing); 1270 kfree(fud); 1271 } 1272 EXPORT_SYMBOL_GPL(fuse_dev_free); 1273 1274 static void fuse_fill_attr_from_inode(struct fuse_attr *attr, 1275 const struct fuse_inode *fi) 1276 { 1277 *attr = (struct fuse_attr){ 1278 .ino = fi->inode.i_ino, 1279 .size = fi->inode.i_size, 1280 .blocks = fi->inode.i_blocks, 1281 .atime = fi->inode.i_atime.tv_sec, 1282 .mtime = fi->inode.i_mtime.tv_sec, 1283 .ctime = fi->inode.i_ctime.tv_sec, 1284 .atimensec = fi->inode.i_atime.tv_nsec, 1285 .mtimensec = fi->inode.i_mtime.tv_nsec, 1286 .ctimensec = fi->inode.i_ctime.tv_nsec, 1287 .mode = fi->inode.i_mode, 1288 .nlink = fi->inode.i_nlink, 1289 .uid = fi->inode.i_uid.val, 1290 .gid = fi->inode.i_gid.val, 1291 .rdev = fi->inode.i_rdev, 1292 .blksize = 1u << fi->inode.i_blkbits, 1293 }; 1294 } 1295 1296 static void fuse_sb_defaults(struct super_block *sb) 1297 { 1298 sb->s_magic = FUSE_SUPER_MAGIC; 1299 sb->s_op = &fuse_super_operations; 1300 sb->s_xattr = fuse_xattr_handlers; 1301 sb->s_maxbytes = MAX_LFS_FILESIZE; 1302 sb->s_time_gran = 1; 1303 sb->s_export_op = &fuse_export_operations; 1304 sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE; 1305 if (sb->s_user_ns != &init_user_ns) 1306 sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER; 1307 sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION); 1308 1309 /* 1310 * If we are not in the initial user namespace posix 1311 * acls must be translated. 1312 */ 1313 if (sb->s_user_ns != &init_user_ns) 1314 sb->s_xattr = fuse_no_acl_xattr_handlers; 1315 } 1316 1317 static int fuse_fill_super_submount(struct super_block *sb, 1318 struct fuse_inode *parent_fi) 1319 { 1320 struct fuse_mount *fm = get_fuse_mount_super(sb); 1321 struct super_block *parent_sb = parent_fi->inode.i_sb; 1322 struct fuse_attr root_attr; 1323 struct inode *root; 1324 1325 fuse_sb_defaults(sb); 1326 fm->sb = sb; 1327 1328 WARN_ON(sb->s_bdi != &noop_backing_dev_info); 1329 sb->s_bdi = bdi_get(parent_sb->s_bdi); 1330 1331 sb->s_xattr = parent_sb->s_xattr; 1332 sb->s_time_gran = parent_sb->s_time_gran; 1333 sb->s_blocksize = parent_sb->s_blocksize; 1334 sb->s_blocksize_bits = parent_sb->s_blocksize_bits; 1335 sb->s_subtype = kstrdup(parent_sb->s_subtype, GFP_KERNEL); 1336 if (parent_sb->s_subtype && !sb->s_subtype) 1337 return -ENOMEM; 1338 1339 fuse_fill_attr_from_inode(&root_attr, parent_fi); 1340 root = fuse_iget(sb, parent_fi->nodeid, 0, &root_attr, 0, 0); 1341 /* 1342 * This inode is just a duplicate, so it is not looked up and 1343 * its nlookup should not be incremented. fuse_iget() does 1344 * that, though, so undo it here. 1345 */ 1346 get_fuse_inode(root)->nlookup--; 1347 sb->s_d_op = &fuse_dentry_operations; 1348 sb->s_root = d_make_root(root); 1349 if (!sb->s_root) 1350 return -ENOMEM; 1351 1352 return 0; 1353 } 1354 1355 /* Filesystem context private data holds the FUSE inode of the mount point */ 1356 static int fuse_get_tree_submount(struct fs_context *fsc) 1357 { 1358 struct fuse_mount *fm; 1359 struct fuse_inode *mp_fi = fsc->fs_private; 1360 struct fuse_conn *fc = get_fuse_conn(&mp_fi->inode); 1361 struct super_block *sb; 1362 int err; 1363 1364 fm = kzalloc(sizeof(struct fuse_mount), GFP_KERNEL); 1365 if (!fm) 1366 return -ENOMEM; 1367 1368 fsc->s_fs_info = fm; 1369 sb = sget_fc(fsc, NULL, set_anon_super_fc); 1370 if (IS_ERR(sb)) { 1371 kfree(fm); 1372 return PTR_ERR(sb); 1373 } 1374 fm->fc = fuse_conn_get(fc); 1375 1376 /* Initialize superblock, making @mp_fi its root */ 1377 err = fuse_fill_super_submount(sb, mp_fi); 1378 if (err) { 1379 fuse_conn_put(fc); 1380 kfree(fm); 1381 sb->s_fs_info = NULL; 1382 deactivate_locked_super(sb); 1383 return err; 1384 } 1385 1386 down_write(&fc->killsb); 1387 list_add_tail(&fm->fc_entry, &fc->mounts); 1388 up_write(&fc->killsb); 1389 1390 sb->s_flags |= SB_ACTIVE; 1391 fsc->root = dget(sb->s_root); 1392 1393 return 0; 1394 } 1395 1396 static const struct fs_context_operations fuse_context_submount_ops = { 1397 .get_tree = fuse_get_tree_submount, 1398 }; 1399 1400 int fuse_init_fs_context_submount(struct fs_context *fsc) 1401 { 1402 fsc->ops = &fuse_context_submount_ops; 1403 return 0; 1404 } 1405 EXPORT_SYMBOL_GPL(fuse_init_fs_context_submount); 1406 1407 int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx) 1408 { 1409 struct fuse_dev *fud = NULL; 1410 struct fuse_mount *fm = get_fuse_mount_super(sb); 1411 struct fuse_conn *fc = fm->fc; 1412 struct inode *root; 1413 struct dentry *root_dentry; 1414 int err; 1415 1416 err = -EINVAL; 1417 if (sb->s_flags & SB_MANDLOCK) 1418 goto err; 1419 1420 fuse_sb_defaults(sb); 1421 1422 if (ctx->is_bdev) { 1423 #ifdef CONFIG_BLOCK 1424 err = -EINVAL; 1425 if (!sb_set_blocksize(sb, ctx->blksize)) 1426 goto err; 1427 #endif 1428 } else { 1429 sb->s_blocksize = PAGE_SIZE; 1430 sb->s_blocksize_bits = PAGE_SHIFT; 1431 } 1432 1433 sb->s_subtype = ctx->subtype; 1434 ctx->subtype = NULL; 1435 if (IS_ENABLED(CONFIG_FUSE_DAX)) { 1436 err = fuse_dax_conn_alloc(fc, ctx->dax_dev); 1437 if (err) 1438 goto err; 1439 } 1440 1441 if (ctx->fudptr) { 1442 err = -ENOMEM; 1443 fud = fuse_dev_alloc_install(fc); 1444 if (!fud) 1445 goto err_free_dax; 1446 } 1447 1448 fc->dev = sb->s_dev; 1449 fm->sb = sb; 1450 err = fuse_bdi_init(fc, sb); 1451 if (err) 1452 goto err_dev_free; 1453 1454 /* Handle umasking inside the fuse code */ 1455 if (sb->s_flags & SB_POSIXACL) 1456 fc->dont_mask = 1; 1457 sb->s_flags |= SB_POSIXACL; 1458 1459 fc->default_permissions = ctx->default_permissions; 1460 fc->allow_other = ctx->allow_other; 1461 fc->user_id = ctx->user_id; 1462 fc->group_id = ctx->group_id; 1463 fc->legacy_opts_show = ctx->legacy_opts_show; 1464 fc->max_read = max_t(unsigned int, 4096, ctx->max_read); 1465 fc->destroy = ctx->destroy; 1466 fc->no_control = ctx->no_control; 1467 fc->no_force_umount = ctx->no_force_umount; 1468 1469 err = -ENOMEM; 1470 root = fuse_get_root_inode(sb, ctx->rootmode); 1471 sb->s_d_op = &fuse_root_dentry_operations; 1472 root_dentry = d_make_root(root); 1473 if (!root_dentry) 1474 goto err_dev_free; 1475 /* Root dentry doesn't have .d_revalidate */ 1476 sb->s_d_op = &fuse_dentry_operations; 1477 1478 mutex_lock(&fuse_mutex); 1479 err = -EINVAL; 1480 if (ctx->fudptr && *ctx->fudptr) 1481 goto err_unlock; 1482 1483 err = fuse_ctl_add_conn(fc); 1484 if (err) 1485 goto err_unlock; 1486 1487 list_add_tail(&fc->entry, &fuse_conn_list); 1488 sb->s_root = root_dentry; 1489 if (ctx->fudptr) 1490 *ctx->fudptr = fud; 1491 mutex_unlock(&fuse_mutex); 1492 return 0; 1493 1494 err_unlock: 1495 mutex_unlock(&fuse_mutex); 1496 dput(root_dentry); 1497 err_dev_free: 1498 if (fud) 1499 fuse_dev_free(fud); 1500 err_free_dax: 1501 if (IS_ENABLED(CONFIG_FUSE_DAX)) 1502 fuse_dax_conn_free(fc); 1503 err: 1504 return err; 1505 } 1506 EXPORT_SYMBOL_GPL(fuse_fill_super_common); 1507 1508 static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc) 1509 { 1510 struct fuse_fs_context *ctx = fsc->fs_private; 1511 struct file *file; 1512 int err; 1513 struct fuse_conn *fc; 1514 struct fuse_mount *fm; 1515 1516 err = -EINVAL; 1517 file = fget(ctx->fd); 1518 if (!file) 1519 goto err; 1520 1521 /* 1522 * Require mount to happen from the same user namespace which 1523 * opened /dev/fuse to prevent potential attacks. 1524 */ 1525 if ((file->f_op != &fuse_dev_operations) || 1526 (file->f_cred->user_ns != sb->s_user_ns)) 1527 goto err_fput; 1528 ctx->fudptr = &file->private_data; 1529 1530 fc = kmalloc(sizeof(*fc), GFP_KERNEL); 1531 err = -ENOMEM; 1532 if (!fc) 1533 goto err_fput; 1534 1535 fm = kzalloc(sizeof(*fm), GFP_KERNEL); 1536 if (!fm) { 1537 kfree(fc); 1538 goto err_fput; 1539 } 1540 1541 fuse_conn_init(fc, fm, sb->s_user_ns, &fuse_dev_fiq_ops, NULL); 1542 fc->release = fuse_free_conn; 1543 1544 sb->s_fs_info = fm; 1545 1546 err = fuse_fill_super_common(sb, ctx); 1547 if (err) 1548 goto err_put_conn; 1549 /* 1550 * atomic_dec_and_test() in fput() provides the necessary 1551 * memory barrier for file->private_data to be visible on all 1552 * CPUs after this 1553 */ 1554 fput(file); 1555 fuse_send_init(get_fuse_mount_super(sb)); 1556 return 0; 1557 1558 err_put_conn: 1559 fuse_conn_put(fc); 1560 kfree(fm); 1561 sb->s_fs_info = NULL; 1562 err_fput: 1563 fput(file); 1564 err: 1565 return err; 1566 } 1567 1568 static int fuse_get_tree(struct fs_context *fc) 1569 { 1570 struct fuse_fs_context *ctx = fc->fs_private; 1571 1572 if (!ctx->fd_present || !ctx->rootmode_present || 1573 !ctx->user_id_present || !ctx->group_id_present) 1574 return -EINVAL; 1575 1576 #ifdef CONFIG_BLOCK 1577 if (ctx->is_bdev) 1578 return get_tree_bdev(fc, fuse_fill_super); 1579 #endif 1580 1581 return get_tree_nodev(fc, fuse_fill_super); 1582 } 1583 1584 static const struct fs_context_operations fuse_context_ops = { 1585 .free = fuse_free_fc, 1586 .parse_param = fuse_parse_param, 1587 .reconfigure = fuse_reconfigure, 1588 .get_tree = fuse_get_tree, 1589 }; 1590 1591 /* 1592 * Set up the filesystem mount context. 1593 */ 1594 static int fuse_init_fs_context(struct fs_context *fc) 1595 { 1596 struct fuse_fs_context *ctx; 1597 1598 ctx = kzalloc(sizeof(struct fuse_fs_context), GFP_KERNEL); 1599 if (!ctx) 1600 return -ENOMEM; 1601 1602 ctx->max_read = ~0; 1603 ctx->blksize = FUSE_DEFAULT_BLKSIZE; 1604 ctx->legacy_opts_show = true; 1605 1606 #ifdef CONFIG_BLOCK 1607 if (fc->fs_type == &fuseblk_fs_type) { 1608 ctx->is_bdev = true; 1609 ctx->destroy = true; 1610 } 1611 #endif 1612 1613 fc->fs_private = ctx; 1614 fc->ops = &fuse_context_ops; 1615 return 0; 1616 } 1617 1618 bool fuse_mount_remove(struct fuse_mount *fm) 1619 { 1620 struct fuse_conn *fc = fm->fc; 1621 bool last = false; 1622 1623 down_write(&fc->killsb); 1624 list_del_init(&fm->fc_entry); 1625 if (list_empty(&fc->mounts)) 1626 last = true; 1627 up_write(&fc->killsb); 1628 1629 return last; 1630 } 1631 EXPORT_SYMBOL_GPL(fuse_mount_remove); 1632 1633 void fuse_conn_destroy(struct fuse_mount *fm) 1634 { 1635 struct fuse_conn *fc = fm->fc; 1636 1637 if (fc->destroy) 1638 fuse_send_destroy(fm); 1639 1640 fuse_abort_conn(fc); 1641 fuse_wait_aborted(fc); 1642 1643 if (!list_empty(&fc->entry)) { 1644 mutex_lock(&fuse_mutex); 1645 list_del(&fc->entry); 1646 fuse_ctl_remove_conn(fc); 1647 mutex_unlock(&fuse_mutex); 1648 } 1649 } 1650 EXPORT_SYMBOL_GPL(fuse_conn_destroy); 1651 1652 static void fuse_sb_destroy(struct super_block *sb) 1653 { 1654 struct fuse_mount *fm = get_fuse_mount_super(sb); 1655 bool last; 1656 1657 if (fm) { 1658 last = fuse_mount_remove(fm); 1659 if (last) 1660 fuse_conn_destroy(fm); 1661 } 1662 } 1663 1664 static void fuse_kill_sb_anon(struct super_block *sb) 1665 { 1666 fuse_sb_destroy(sb); 1667 kill_anon_super(sb); 1668 } 1669 1670 static struct file_system_type fuse_fs_type = { 1671 .owner = THIS_MODULE, 1672 .name = "fuse", 1673 .fs_flags = FS_HAS_SUBTYPE | FS_USERNS_MOUNT, 1674 .init_fs_context = fuse_init_fs_context, 1675 .parameters = fuse_fs_parameters, 1676 .kill_sb = fuse_kill_sb_anon, 1677 }; 1678 MODULE_ALIAS_FS("fuse"); 1679 1680 #ifdef CONFIG_BLOCK 1681 static void fuse_kill_sb_blk(struct super_block *sb) 1682 { 1683 fuse_sb_destroy(sb); 1684 kill_block_super(sb); 1685 } 1686 1687 static struct file_system_type fuseblk_fs_type = { 1688 .owner = THIS_MODULE, 1689 .name = "fuseblk", 1690 .init_fs_context = fuse_init_fs_context, 1691 .parameters = fuse_fs_parameters, 1692 .kill_sb = fuse_kill_sb_blk, 1693 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE, 1694 }; 1695 MODULE_ALIAS_FS("fuseblk"); 1696 1697 static inline int register_fuseblk(void) 1698 { 1699 return register_filesystem(&fuseblk_fs_type); 1700 } 1701 1702 static inline void unregister_fuseblk(void) 1703 { 1704 unregister_filesystem(&fuseblk_fs_type); 1705 } 1706 #else 1707 static inline int register_fuseblk(void) 1708 { 1709 return 0; 1710 } 1711 1712 static inline void unregister_fuseblk(void) 1713 { 1714 } 1715 #endif 1716 1717 static void fuse_inode_init_once(void *foo) 1718 { 1719 struct inode *inode = foo; 1720 1721 inode_init_once(inode); 1722 } 1723 1724 static int __init fuse_fs_init(void) 1725 { 1726 int err; 1727 1728 fuse_inode_cachep = kmem_cache_create("fuse_inode", 1729 sizeof(struct fuse_inode), 0, 1730 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT, 1731 fuse_inode_init_once); 1732 err = -ENOMEM; 1733 if (!fuse_inode_cachep) 1734 goto out; 1735 1736 err = register_fuseblk(); 1737 if (err) 1738 goto out2; 1739 1740 err = register_filesystem(&fuse_fs_type); 1741 if (err) 1742 goto out3; 1743 1744 return 0; 1745 1746 out3: 1747 unregister_fuseblk(); 1748 out2: 1749 kmem_cache_destroy(fuse_inode_cachep); 1750 out: 1751 return err; 1752 } 1753 1754 static void fuse_fs_cleanup(void) 1755 { 1756 unregister_filesystem(&fuse_fs_type); 1757 unregister_fuseblk(); 1758 1759 /* 1760 * Make sure all delayed rcu free inodes are flushed before we 1761 * destroy cache. 1762 */ 1763 rcu_barrier(); 1764 kmem_cache_destroy(fuse_inode_cachep); 1765 } 1766 1767 static struct kobject *fuse_kobj; 1768 1769 static int fuse_sysfs_init(void) 1770 { 1771 int err; 1772 1773 fuse_kobj = kobject_create_and_add("fuse", fs_kobj); 1774 if (!fuse_kobj) { 1775 err = -ENOMEM; 1776 goto out_err; 1777 } 1778 1779 err = sysfs_create_mount_point(fuse_kobj, "connections"); 1780 if (err) 1781 goto out_fuse_unregister; 1782 1783 return 0; 1784 1785 out_fuse_unregister: 1786 kobject_put(fuse_kobj); 1787 out_err: 1788 return err; 1789 } 1790 1791 static void fuse_sysfs_cleanup(void) 1792 { 1793 sysfs_remove_mount_point(fuse_kobj, "connections"); 1794 kobject_put(fuse_kobj); 1795 } 1796 1797 static int __init fuse_init(void) 1798 { 1799 int res; 1800 1801 pr_info("init (API version %i.%i)\n", 1802 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION); 1803 1804 INIT_LIST_HEAD(&fuse_conn_list); 1805 res = fuse_fs_init(); 1806 if (res) 1807 goto err; 1808 1809 res = fuse_dev_init(); 1810 if (res) 1811 goto err_fs_cleanup; 1812 1813 res = fuse_sysfs_init(); 1814 if (res) 1815 goto err_dev_cleanup; 1816 1817 res = fuse_ctl_init(); 1818 if (res) 1819 goto err_sysfs_cleanup; 1820 1821 sanitize_global_limit(&max_user_bgreq); 1822 sanitize_global_limit(&max_user_congthresh); 1823 1824 return 0; 1825 1826 err_sysfs_cleanup: 1827 fuse_sysfs_cleanup(); 1828 err_dev_cleanup: 1829 fuse_dev_cleanup(); 1830 err_fs_cleanup: 1831 fuse_fs_cleanup(); 1832 err: 1833 return res; 1834 } 1835 1836 static void __exit fuse_exit(void) 1837 { 1838 pr_debug("exit\n"); 1839 1840 fuse_ctl_cleanup(); 1841 fuse_sysfs_cleanup(); 1842 fuse_fs_cleanup(); 1843 fuse_dev_cleanup(); 1844 } 1845 1846 module_init(fuse_init); 1847 module_exit(fuse_exit); 1848