1// SPDX-License-Identifier: GPL-2.0 2/* 3 * linux/fs/reiserfs/xattr.c 4 * 5 * Copyright (c) 2002 by Jeff Mahoney, <jeffm@suse.com> 6 * 7 */ 8 9/* 10 * In order to implement EA/ACLs in a clean, backwards compatible manner, 11 * they are implemented as files in a "private" directory. 12 * Each EA is in it's own file, with the directory layout like so (/ is assumed 13 * to be relative to fs root). Inside the /.reiserfs_priv/xattrs directory, 14 * directories named using the capital-hex form of the objectid and 15 * generation number are used. Inside each directory are individual files 16 * named with the name of the extended attribute. 17 * 18 * So, for objectid 12648430, we could have: 19 * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_access 20 * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_default 21 * /.reiserfs_priv/xattrs/C0FFEE.0/user.Content-Type 22 * .. or similar. 23 * 24 * The file contents are the text of the EA. The size is known based on the 25 * stat data describing the file. 26 * 27 * In the case of system.posix_acl_access and system.posix_acl_default, since 28 * these are special cases for filesystem ACLs, they are interpreted by the 29 * kernel, in addition, they are negatively and positively cached and attached 30 * to the inode so that unnecessary lookups are avoided. 31 * 32 * Locking works like so: 33 * Directory components (xattr root, xattr dir) are protectd by their i_mutex. 34 * The xattrs themselves are protected by the xattr_sem. 35 */ 36 37#include "reiserfs.h" 38#include <linux/capability.h> 39#include <linux/dcache.h> 40#include <linux/namei.h> 41#include <linux/errno.h> 42#include <linux/gfp.h> 43#include <linux/fs.h> 44#include <linux/file.h> 45#include <linux/pagemap.h> 46#include <linux/xattr.h> 47#include "xattr.h" 48#include "acl.h" 49#include <linux/uaccess.h> 50#include <net/checksum.h> 51#include <linux/stat.h> 52#include <linux/quotaops.h> 53#include <linux/security.h> 54#include <linux/posix_acl_xattr.h> 55#include <linux/xattr.h> 56 57#define PRIVROOT_NAME ".reiserfs_priv" 58#define XAROOT_NAME "xattrs" 59 60 61/* 62 * Helpers for inode ops. We do this so that we don't have all the VFS 63 * overhead and also for proper i_mutex annotation. 64 * dir->i_mutex must be held for all of them. 65 */ 66#ifdef CONFIG_REISERFS_FS_XATTR 67static int xattr_create(struct inode *dir, struct dentry *dentry, int mode) 68{ 69 BUG_ON(!inode_is_locked(dir)); 70 return dir->i_op->create(&nop_mnt_idmap, dir, dentry, mode, true); 71} 72#endif 73 74static int xattr_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) 75{ 76 BUG_ON(!inode_is_locked(dir)); 77 return dir->i_op->mkdir(&nop_mnt_idmap, dir, dentry, mode); 78} 79 80/* 81 * We use I_MUTEX_CHILD here to silence lockdep. It's safe because xattr 82 * mutation ops aren't called during rename or splace, which are the 83 * only other users of I_MUTEX_CHILD. It violates the ordering, but that's 84 * better than allocating another subclass just for this code. 85 */ 86static int xattr_unlink(struct inode *dir, struct dentry *dentry) 87{ 88 int error; 89 90 BUG_ON(!inode_is_locked(dir)); 91 92 inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD); 93 error = dir->i_op->unlink(dir, dentry); 94 inode_unlock(d_inode(dentry)); 95 96 if (!error) 97 d_delete(dentry); 98 return error; 99} 100 101static int xattr_rmdir(struct inode *dir, struct dentry *dentry) 102{ 103 int error; 104 105 BUG_ON(!inode_is_locked(dir)); 106 107 inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD); 108 error = dir->i_op->rmdir(dir, dentry); 109 if (!error) 110 d_inode(dentry)->i_flags |= S_DEAD; 111 inode_unlock(d_inode(dentry)); 112 if (!error) 113 d_delete(dentry); 114 115 return error; 116} 117 118#define xattr_may_create(flags) (!flags || flags & XATTR_CREATE) 119 120static struct dentry *open_xa_root(struct super_block *sb, int flags) 121{ 122 struct dentry *privroot = REISERFS_SB(sb)->priv_root; 123 struct dentry *xaroot; 124 125 if (d_really_is_negative(privroot)) 126 return ERR_PTR(-EOPNOTSUPP); 127 128 inode_lock_nested(d_inode(privroot), I_MUTEX_XATTR); 129 130 xaroot = dget(REISERFS_SB(sb)->xattr_root); 131 if (!xaroot) 132 xaroot = ERR_PTR(-EOPNOTSUPP); 133 else if (d_really_is_negative(xaroot)) { 134 int err = -ENODATA; 135 136 if (xattr_may_create(flags)) 137 err = xattr_mkdir(d_inode(privroot), xaroot, 0700); 138 if (err) { 139 dput(xaroot); 140 xaroot = ERR_PTR(err); 141 } 142 } 143 144 inode_unlock(d_inode(privroot)); 145 return xaroot; 146} 147 148static struct dentry *open_xa_dir(const struct inode *inode, int flags) 149{ 150 struct dentry *xaroot, *xadir; 151 char namebuf[17]; 152 153 xaroot = open_xa_root(inode->i_sb, flags); 154 if (IS_ERR(xaroot)) 155 return xaroot; 156 157 snprintf(namebuf, sizeof(namebuf), "%X.%X", 158 le32_to_cpu(INODE_PKEY(inode)->k_objectid), 159 inode->i_generation); 160 161 inode_lock_nested(d_inode(xaroot), I_MUTEX_XATTR); 162 163 xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf)); 164 if (!IS_ERR(xadir) && d_really_is_negative(xadir)) { 165 int err = -ENODATA; 166 167 if (xattr_may_create(flags)) 168 err = xattr_mkdir(d_inode(xaroot), xadir, 0700); 169 if (err) { 170 dput(xadir); 171 xadir = ERR_PTR(err); 172 } 173 } 174 175 inode_unlock(d_inode(xaroot)); 176 dput(xaroot); 177 return xadir; 178} 179 180/* 181 * The following are side effects of other operations that aren't explicitly 182 * modifying extended attributes. This includes operations such as permissions 183 * or ownership changes, object deletions, etc. 184 */ 185struct reiserfs_dentry_buf { 186 struct dir_context ctx; 187 struct dentry *xadir; 188 int count; 189 int err; 190 struct dentry *dentries[8]; 191}; 192 193static bool 194fill_with_dentries(struct dir_context *ctx, const char *name, int namelen, 195 loff_t offset, u64 ino, unsigned int d_type) 196{ 197 struct reiserfs_dentry_buf *dbuf = 198 container_of(ctx, struct reiserfs_dentry_buf, ctx); 199 struct dentry *dentry; 200 201 WARN_ON_ONCE(!inode_is_locked(d_inode(dbuf->xadir))); 202 203 if (dbuf->count == ARRAY_SIZE(dbuf->dentries)) 204 return false; 205 206 if (name[0] == '.' && (namelen < 2 || 207 (namelen == 2 && name[1] == '.'))) 208 return true; 209 210 dentry = lookup_one_len(name, dbuf->xadir, namelen); 211 if (IS_ERR(dentry)) { 212 dbuf->err = PTR_ERR(dentry); 213 return false; 214 } else if (d_really_is_negative(dentry)) { 215 /* A directory entry exists, but no file? */ 216 reiserfs_error(dentry->d_sb, "xattr-20003", 217 "Corrupted directory: xattr %pd listed but " 218 "not found for file %pd.\n", 219 dentry, dbuf->xadir); 220 dput(dentry); 221 dbuf->err = -EIO; 222 return false; 223 } 224 225 dbuf->dentries[dbuf->count++] = dentry; 226 return true; 227} 228 229static void 230cleanup_dentry_buf(struct reiserfs_dentry_buf *buf) 231{ 232 int i; 233 234 for (i = 0; i < buf->count; i++) 235 if (buf->dentries[i]) 236 dput(buf->dentries[i]); 237} 238 239static int reiserfs_for_each_xattr(struct inode *inode, 240 int (*action)(struct dentry *, void *), 241 void *data) 242{ 243 struct dentry *dir; 244 int i, err = 0; 245 struct reiserfs_dentry_buf buf = { 246 .ctx.actor = fill_with_dentries, 247 }; 248 249 /* Skip out, an xattr has no xattrs associated with it */ 250 if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1) 251 return 0; 252 253 dir = open_xa_dir(inode, XATTR_REPLACE); 254 if (IS_ERR(dir)) { 255 err = PTR_ERR(dir); 256 goto out; 257 } else if (d_really_is_negative(dir)) { 258 err = 0; 259 goto out_dir; 260 } 261 262 inode_lock_nested(d_inode(dir), I_MUTEX_XATTR); 263 264 buf.xadir = dir; 265 while (1) { 266 err = reiserfs_readdir_inode(d_inode(dir), &buf.ctx); 267 if (err) 268 break; 269 if (buf.err) { 270 err = buf.err; 271 break; 272 } 273 if (!buf.count) 274 break; 275 for (i = 0; !err && i < buf.count && buf.dentries[i]; i++) { 276 struct dentry *dentry = buf.dentries[i]; 277 278 if (!d_is_dir(dentry)) 279 err = action(dentry, data); 280 281 dput(dentry); 282 buf.dentries[i] = NULL; 283 } 284 if (err) 285 break; 286 buf.count = 0; 287 } 288 inode_unlock(d_inode(dir)); 289 290 cleanup_dentry_buf(&buf); 291 292 if (!err) { 293 /* 294 * We start a transaction here to avoid a ABBA situation 295 * between the xattr root's i_mutex and the journal lock. 296 * This doesn't incur much additional overhead since the 297 * new transaction will just nest inside the 298 * outer transaction. 299 */ 300 int blocks = JOURNAL_PER_BALANCE_CNT * 2 + 2 + 301 4 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb); 302 struct reiserfs_transaction_handle th; 303 304 reiserfs_write_lock(inode->i_sb); 305 err = journal_begin(&th, inode->i_sb, blocks); 306 reiserfs_write_unlock(inode->i_sb); 307 if (!err) { 308 int jerror; 309 310 inode_lock_nested(d_inode(dir->d_parent), 311 I_MUTEX_XATTR); 312 err = action(dir, data); 313 reiserfs_write_lock(inode->i_sb); 314 jerror = journal_end(&th); 315 reiserfs_write_unlock(inode->i_sb); 316 inode_unlock(d_inode(dir->d_parent)); 317 err = jerror ?: err; 318 } 319 } 320out_dir: 321 dput(dir); 322out: 323 /* 324 * -ENODATA: this object doesn't have any xattrs 325 * -EOPNOTSUPP: this file system doesn't have xattrs enabled on disk. 326 * Neither are errors 327 */ 328 if (err == -ENODATA || err == -EOPNOTSUPP) 329 err = 0; 330 return err; 331} 332 333static int delete_one_xattr(struct dentry *dentry, void *data) 334{ 335 struct inode *dir = d_inode(dentry->d_parent); 336 337 /* This is the xattr dir, handle specially. */ 338 if (d_is_dir(dentry)) 339 return xattr_rmdir(dir, dentry); 340 341 return xattr_unlink(dir, dentry); 342} 343 344static int chown_one_xattr(struct dentry *dentry, void *data) 345{ 346 struct iattr *attrs = data; 347 int ia_valid = attrs->ia_valid; 348 int err; 349 350 /* 351 * We only want the ownership bits. Otherwise, we'll do 352 * things like change a directory to a regular file if 353 * ATTR_MODE is set. 354 */ 355 attrs->ia_valid &= (ATTR_UID|ATTR_GID); 356 err = reiserfs_setattr(&nop_mnt_idmap, dentry, attrs); 357 attrs->ia_valid = ia_valid; 358 359 return err; 360} 361 362/* No i_mutex, but the inode is unconnected. */ 363int reiserfs_delete_xattrs(struct inode *inode) 364{ 365 int err = reiserfs_for_each_xattr(inode, delete_one_xattr, NULL); 366 367 if (err) 368 reiserfs_warning(inode->i_sb, "jdm-20004", 369 "Couldn't delete all xattrs (%d)\n", err); 370 return err; 371} 372 373/* inode->i_mutex: down */ 374int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs) 375{ 376 int err = reiserfs_for_each_xattr(inode, chown_one_xattr, attrs); 377 378 if (err) 379 reiserfs_warning(inode->i_sb, "jdm-20007", 380 "Couldn't chown all xattrs (%d)\n", err); 381 return err; 382} 383 384#ifdef CONFIG_REISERFS_FS_XATTR 385/* 386 * Returns a dentry corresponding to a specific extended attribute file 387 * for the inode. If flags allow, the file is created. Otherwise, a 388 * valid or negative dentry, or an error is returned. 389 */ 390static struct dentry *xattr_lookup(struct inode *inode, const char *name, 391 int flags) 392{ 393 struct dentry *xadir, *xafile; 394 int err = 0; 395 396 xadir = open_xa_dir(inode, flags); 397 if (IS_ERR(xadir)) 398 return ERR_CAST(xadir); 399 400 inode_lock_nested(d_inode(xadir), I_MUTEX_XATTR); 401 xafile = lookup_one_len(name, xadir, strlen(name)); 402 if (IS_ERR(xafile)) { 403 err = PTR_ERR(xafile); 404 goto out; 405 } 406 407 if (d_really_is_positive(xafile) && (flags & XATTR_CREATE)) 408 err = -EEXIST; 409 410 if (d_really_is_negative(xafile)) { 411 err = -ENODATA; 412 if (xattr_may_create(flags)) 413 err = xattr_create(d_inode(xadir), xafile, 414 0700|S_IFREG); 415 } 416 417 if (err) 418 dput(xafile); 419out: 420 inode_unlock(d_inode(xadir)); 421 dput(xadir); 422 if (err) 423 return ERR_PTR(err); 424 return xafile; 425} 426 427/* Internal operations on file data */ 428static inline void reiserfs_put_page(struct page *page) 429{ 430 kunmap(page); 431 put_page(page); 432} 433 434static struct page *reiserfs_get_page(struct inode *dir, size_t n) 435{ 436 struct address_space *mapping = dir->i_mapping; 437 struct page *page; 438 /* 439 * We can deadlock if we try to free dentries, 440 * and an unlink/rmdir has just occurred - GFP_NOFS avoids this 441 */ 442 mapping_set_gfp_mask(mapping, GFP_NOFS); 443 page = read_mapping_page(mapping, n >> PAGE_SHIFT, NULL); 444 if (!IS_ERR(page)) 445 kmap(page); 446 return page; 447} 448 449static inline __u32 xattr_hash(const char *msg, int len) 450{ 451 /* 452 * csum_partial() gives different results for little-endian and 453 * big endian hosts. Images created on little-endian hosts and 454 * mounted on big-endian hosts(and vice versa) will see csum mismatches 455 * when trying to fetch xattrs. Treating the hash as __wsum_t would 456 * lower the frequency of mismatch. This is an endianness bug in 457 * reiserfs. The return statement would result in a sparse warning. Do 458 * not fix the sparse warning so as to not hide a reminder of the bug. 459 */ 460 return csum_partial(msg, len, 0); 461} 462 463int reiserfs_commit_write(struct file *f, struct page *page, 464 unsigned from, unsigned to); 465 466static void update_ctime(struct inode *inode) 467{ 468 struct timespec64 now = current_time(inode); 469 struct timespec64 ctime = inode_get_ctime(inode); 470 471 if (inode_unhashed(inode) || !inode->i_nlink || 472 timespec64_equal(&ctime, &now)) 473 return; 474 475 inode_set_ctime_to_ts(inode, now); 476 mark_inode_dirty(inode); 477} 478 479static int lookup_and_delete_xattr(struct inode *inode, const char *name) 480{ 481 int err = 0; 482 struct dentry *dentry, *xadir; 483 484 xadir = open_xa_dir(inode, XATTR_REPLACE); 485 if (IS_ERR(xadir)) 486 return PTR_ERR(xadir); 487 488 inode_lock_nested(d_inode(xadir), I_MUTEX_XATTR); 489 dentry = lookup_one_len(name, xadir, strlen(name)); 490 if (IS_ERR(dentry)) { 491 err = PTR_ERR(dentry); 492 goto out_dput; 493 } 494 495 if (d_really_is_positive(dentry)) { 496 err = xattr_unlink(d_inode(xadir), dentry); 497 update_ctime(inode); 498 } 499 500 dput(dentry); 501out_dput: 502 inode_unlock(d_inode(xadir)); 503 dput(xadir); 504 return err; 505} 506 507 508/* Generic extended attribute operations that can be used by xa plugins */ 509 510/* 511 * inode->i_mutex: down 512 */ 513int 514reiserfs_xattr_set_handle(struct reiserfs_transaction_handle *th, 515 struct inode *inode, const char *name, 516 const void *buffer, size_t buffer_size, int flags) 517{ 518 int err = 0; 519 struct dentry *dentry; 520 struct page *page; 521 char *data; 522 size_t file_pos = 0; 523 size_t buffer_pos = 0; 524 size_t new_size; 525 __u32 xahash = 0; 526 527 if (get_inode_sd_version(inode) == STAT_DATA_V1) 528 return -EOPNOTSUPP; 529 530 if (!buffer) { 531 err = lookup_and_delete_xattr(inode, name); 532 return err; 533 } 534 535 dentry = xattr_lookup(inode, name, flags); 536 if (IS_ERR(dentry)) 537 return PTR_ERR(dentry); 538 539 down_write(&REISERFS_I(inode)->i_xattr_sem); 540 541 xahash = xattr_hash(buffer, buffer_size); 542 while (buffer_pos < buffer_size || buffer_pos == 0) { 543 size_t chunk; 544 size_t skip = 0; 545 size_t page_offset = (file_pos & (PAGE_SIZE - 1)); 546 547 if (buffer_size - buffer_pos > PAGE_SIZE) 548 chunk = PAGE_SIZE; 549 else 550 chunk = buffer_size - buffer_pos; 551 552 page = reiserfs_get_page(d_inode(dentry), file_pos); 553 if (IS_ERR(page)) { 554 err = PTR_ERR(page); 555 goto out_unlock; 556 } 557 558 lock_page(page); 559 data = page_address(page); 560 561 if (file_pos == 0) { 562 struct reiserfs_xattr_header *rxh; 563 564 skip = file_pos = sizeof(struct reiserfs_xattr_header); 565 if (chunk + skip > PAGE_SIZE) 566 chunk = PAGE_SIZE - skip; 567 rxh = (struct reiserfs_xattr_header *)data; 568 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC); 569 rxh->h_hash = cpu_to_le32(xahash); 570 } 571 572 reiserfs_write_lock(inode->i_sb); 573 err = __reiserfs_write_begin(page, page_offset, chunk + skip); 574 if (!err) { 575 if (buffer) 576 memcpy(data + skip, buffer + buffer_pos, chunk); 577 err = reiserfs_commit_write(NULL, page, page_offset, 578 page_offset + chunk + 579 skip); 580 } 581 reiserfs_write_unlock(inode->i_sb); 582 unlock_page(page); 583 reiserfs_put_page(page); 584 buffer_pos += chunk; 585 file_pos += chunk; 586 skip = 0; 587 if (err || buffer_size == 0 || !buffer) 588 break; 589 } 590 591 new_size = buffer_size + sizeof(struct reiserfs_xattr_header); 592 if (!err && new_size < i_size_read(d_inode(dentry))) { 593 struct iattr newattrs = { 594 .ia_ctime = current_time(inode), 595 .ia_size = new_size, 596 .ia_valid = ATTR_SIZE | ATTR_CTIME, 597 }; 598 599 inode_lock_nested(d_inode(dentry), I_MUTEX_XATTR); 600 inode_dio_wait(d_inode(dentry)); 601 602 err = reiserfs_setattr(&nop_mnt_idmap, dentry, &newattrs); 603 inode_unlock(d_inode(dentry)); 604 } else 605 update_ctime(inode); 606out_unlock: 607 up_write(&REISERFS_I(inode)->i_xattr_sem); 608 dput(dentry); 609 return err; 610} 611 612/* We need to start a transaction to maintain lock ordering */ 613int reiserfs_xattr_set(struct inode *inode, const char *name, 614 const void *buffer, size_t buffer_size, int flags) 615{ 616 617 struct reiserfs_transaction_handle th; 618 int error, error2; 619 size_t jbegin_count = reiserfs_xattr_nblocks(inode, buffer_size); 620 621 /* Check before we start a transaction and then do nothing. */ 622 if (!d_really_is_positive(REISERFS_SB(inode->i_sb)->priv_root)) 623 return -EOPNOTSUPP; 624 625 if (!(flags & XATTR_REPLACE)) 626 jbegin_count += reiserfs_xattr_jcreate_nblocks(inode); 627 628 reiserfs_write_lock(inode->i_sb); 629 error = journal_begin(&th, inode->i_sb, jbegin_count); 630 reiserfs_write_unlock(inode->i_sb); 631 if (error) { 632 return error; 633 } 634 635 error = reiserfs_xattr_set_handle(&th, inode, name, 636 buffer, buffer_size, flags); 637 638 reiserfs_write_lock(inode->i_sb); 639 error2 = journal_end(&th); 640 reiserfs_write_unlock(inode->i_sb); 641 if (error == 0) 642 error = error2; 643 644 return error; 645} 646 647/* 648 * inode->i_mutex: down 649 */ 650int 651reiserfs_xattr_get(struct inode *inode, const char *name, void *buffer, 652 size_t buffer_size) 653{ 654 ssize_t err = 0; 655 struct dentry *dentry; 656 size_t isize; 657 size_t file_pos = 0; 658 size_t buffer_pos = 0; 659 struct page *page; 660 __u32 hash = 0; 661 662 if (name == NULL) 663 return -EINVAL; 664 665 /* 666 * We can't have xattrs attached to v1 items since they don't have 667 * generation numbers 668 */ 669 if (get_inode_sd_version(inode) == STAT_DATA_V1) 670 return -EOPNOTSUPP; 671 672 /* 673 * priv_root needn't be initialized during mount so allow initial 674 * lookups to succeed. 675 */ 676 if (!REISERFS_SB(inode->i_sb)->priv_root) 677 return 0; 678 679 dentry = xattr_lookup(inode, name, XATTR_REPLACE); 680 if (IS_ERR(dentry)) { 681 err = PTR_ERR(dentry); 682 goto out; 683 } 684 685 down_read(&REISERFS_I(inode)->i_xattr_sem); 686 687 isize = i_size_read(d_inode(dentry)); 688 689 /* Just return the size needed */ 690 if (buffer == NULL) { 691 err = isize - sizeof(struct reiserfs_xattr_header); 692 goto out_unlock; 693 } 694 695 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) { 696 err = -ERANGE; 697 goto out_unlock; 698 } 699 700 while (file_pos < isize) { 701 size_t chunk; 702 char *data; 703 size_t skip = 0; 704 705 if (isize - file_pos > PAGE_SIZE) 706 chunk = PAGE_SIZE; 707 else 708 chunk = isize - file_pos; 709 710 page = reiserfs_get_page(d_inode(dentry), file_pos); 711 if (IS_ERR(page)) { 712 err = PTR_ERR(page); 713 goto out_unlock; 714 } 715 716 lock_page(page); 717 data = page_address(page); 718 if (file_pos == 0) { 719 struct reiserfs_xattr_header *rxh = 720 (struct reiserfs_xattr_header *)data; 721 skip = file_pos = sizeof(struct reiserfs_xattr_header); 722 chunk -= skip; 723 /* Magic doesn't match up.. */ 724 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) { 725 unlock_page(page); 726 reiserfs_put_page(page); 727 reiserfs_warning(inode->i_sb, "jdm-20001", 728 "Invalid magic for xattr (%s) " 729 "associated with %k", name, 730 INODE_PKEY(inode)); 731 err = -EIO; 732 goto out_unlock; 733 } 734 hash = le32_to_cpu(rxh->h_hash); 735 } 736 memcpy(buffer + buffer_pos, data + skip, chunk); 737 unlock_page(page); 738 reiserfs_put_page(page); 739 file_pos += chunk; 740 buffer_pos += chunk; 741 skip = 0; 742 } 743 err = isize - sizeof(struct reiserfs_xattr_header); 744 745 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) != 746 hash) { 747 reiserfs_warning(inode->i_sb, "jdm-20002", 748 "Invalid hash for xattr (%s) associated " 749 "with %k", name, INODE_PKEY(inode)); 750 err = -EIO; 751 } 752 753out_unlock: 754 up_read(&REISERFS_I(inode)->i_xattr_sem); 755 dput(dentry); 756 757out: 758 return err; 759} 760 761/* 762 * In order to implement different sets of xattr operations for each xattr 763 * prefix with the generic xattr API, a filesystem should create a 764 * null-terminated array of struct xattr_handler (one for each prefix) and 765 * hang a pointer to it off of the s_xattr field of the superblock. 766 * 767 * The generic_fooxattr() functions will use this list to dispatch xattr 768 * operations to the correct xattr_handler. 769 */ 770#define for_each_xattr_handler(handlers, handler) \ 771 for ((handler) = *(handlers)++; \ 772 (handler) != NULL; \ 773 (handler) = *(handlers)++) 774 775static inline bool reiserfs_posix_acl_list(const char *name, 776 struct dentry *dentry) 777{ 778 return (posix_acl_type(name) >= 0) && 779 IS_POSIXACL(d_backing_inode(dentry)); 780} 781 782/* This is the implementation for the xattr plugin infrastructure */ 783static inline bool reiserfs_xattr_list(const struct xattr_handler * const *handlers, 784 const char *name, struct dentry *dentry) 785{ 786 if (handlers) { 787 const struct xattr_handler *xah = NULL; 788 789 for_each_xattr_handler(handlers, xah) { 790 const char *prefix = xattr_prefix(xah); 791 792 if (strncmp(prefix, name, strlen(prefix))) 793 continue; 794 795 if (!xattr_handler_can_list(xah, dentry)) 796 return false; 797 798 return true; 799 } 800 } 801 802 return reiserfs_posix_acl_list(name, dentry); 803} 804 805struct listxattr_buf { 806 struct dir_context ctx; 807 size_t size; 808 size_t pos; 809 char *buf; 810 struct dentry *dentry; 811}; 812 813static bool listxattr_filler(struct dir_context *ctx, const char *name, 814 int namelen, loff_t offset, u64 ino, 815 unsigned int d_type) 816{ 817 struct listxattr_buf *b = 818 container_of(ctx, struct listxattr_buf, ctx); 819 size_t size; 820 821 if (name[0] != '.' || 822 (namelen != 1 && (name[1] != '.' || namelen != 2))) { 823 if (!reiserfs_xattr_list(b->dentry->d_sb->s_xattr, name, 824 b->dentry)) 825 return true; 826 size = namelen + 1; 827 if (b->buf) { 828 if (b->pos + size > b->size) { 829 b->pos = -ERANGE; 830 return false; 831 } 832 memcpy(b->buf + b->pos, name, namelen); 833 b->buf[b->pos + namelen] = 0; 834 } 835 b->pos += size; 836 } 837 return true; 838} 839 840/* 841 * Inode operation listxattr() 842 * 843 * We totally ignore the generic listxattr here because it would be stupid 844 * not to. Since the xattrs are organized in a directory, we can just 845 * readdir to find them. 846 */ 847ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size) 848{ 849 struct dentry *dir; 850 int err = 0; 851 struct listxattr_buf buf = { 852 .ctx.actor = listxattr_filler, 853 .dentry = dentry, 854 .buf = buffer, 855 .size = buffer ? size : 0, 856 }; 857 858 if (d_really_is_negative(dentry)) 859 return -EINVAL; 860 861 if (get_inode_sd_version(d_inode(dentry)) == STAT_DATA_V1) 862 return -EOPNOTSUPP; 863 864 dir = open_xa_dir(d_inode(dentry), XATTR_REPLACE); 865 if (IS_ERR(dir)) { 866 err = PTR_ERR(dir); 867 if (err == -ENODATA) 868 err = 0; /* Not an error if there aren't any xattrs */ 869 goto out; 870 } 871 872 inode_lock_nested(d_inode(dir), I_MUTEX_XATTR); 873 err = reiserfs_readdir_inode(d_inode(dir), &buf.ctx); 874 inode_unlock(d_inode(dir)); 875 876 if (!err) 877 err = buf.pos; 878 879 dput(dir); 880out: 881 return err; 882} 883 884static int create_privroot(struct dentry *dentry) 885{ 886 int err; 887 struct inode *inode = d_inode(dentry->d_parent); 888 889 WARN_ON_ONCE(!inode_is_locked(inode)); 890 891 err = xattr_mkdir(inode, dentry, 0700); 892 if (err || d_really_is_negative(dentry)) { 893 reiserfs_warning(dentry->d_sb, "jdm-20006", 894 "xattrs/ACLs enabled and couldn't " 895 "find/create .reiserfs_priv. " 896 "Failing mount."); 897 return -EOPNOTSUPP; 898 } 899 900 reiserfs_init_priv_inode(d_inode(dentry)); 901 reiserfs_info(dentry->d_sb, "Created %s - reserved for xattr " 902 "storage.\n", PRIVROOT_NAME); 903 904 return 0; 905} 906 907#else 908int __init reiserfs_xattr_register_handlers(void) { return 0; } 909void reiserfs_xattr_unregister_handlers(void) {} 910static int create_privroot(struct dentry *dentry) { return 0; } 911#endif 912 913/* Actual operations that are exported to VFS-land */ 914const struct xattr_handler * const reiserfs_xattr_handlers[] = { 915#ifdef CONFIG_REISERFS_FS_XATTR 916 &reiserfs_xattr_user_handler, 917 &reiserfs_xattr_trusted_handler, 918#endif 919#ifdef CONFIG_REISERFS_FS_SECURITY 920 &reiserfs_xattr_security_handler, 921#endif 922 NULL 923}; 924 925static int xattr_mount_check(struct super_block *s) 926{ 927 /* 928 * We need generation numbers to ensure that the oid mapping is correct 929 * v3.5 filesystems don't have them. 930 */ 931 if (old_format_only(s)) { 932 if (reiserfs_xattrs_optional(s)) { 933 /* 934 * Old format filesystem, but optional xattrs have 935 * been enabled. Error out. 936 */ 937 reiserfs_warning(s, "jdm-2005", 938 "xattrs/ACLs not supported " 939 "on pre-v3.6 format filesystems. " 940 "Failing mount."); 941 return -EOPNOTSUPP; 942 } 943 } 944 945 return 0; 946} 947 948int reiserfs_permission(struct mnt_idmap *idmap, struct inode *inode, 949 int mask) 950{ 951 /* 952 * We don't do permission checks on the internal objects. 953 * Permissions are determined by the "owning" object. 954 */ 955 if (IS_PRIVATE(inode)) 956 return 0; 957 958 return generic_permission(&nop_mnt_idmap, inode, mask); 959} 960 961static int xattr_hide_revalidate(struct dentry *dentry, unsigned int flags) 962{ 963 return -EPERM; 964} 965 966static const struct dentry_operations xattr_lookup_poison_ops = { 967 .d_revalidate = xattr_hide_revalidate, 968}; 969 970int reiserfs_lookup_privroot(struct super_block *s) 971{ 972 struct dentry *dentry; 973 int err = 0; 974 975 /* If we don't have the privroot located yet - go find it */ 976 inode_lock(d_inode(s->s_root)); 977 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root, 978 strlen(PRIVROOT_NAME)); 979 if (!IS_ERR(dentry)) { 980 REISERFS_SB(s)->priv_root = dentry; 981 d_set_d_op(dentry, &xattr_lookup_poison_ops); 982 if (d_really_is_positive(dentry)) 983 reiserfs_init_priv_inode(d_inode(dentry)); 984 } else 985 err = PTR_ERR(dentry); 986 inode_unlock(d_inode(s->s_root)); 987 988 return err; 989} 990 991/* 992 * We need to take a copy of the mount flags since things like 993 * SB_RDONLY don't get set until *after* we're called. 994 * mount_flags != mount_options 995 */ 996int reiserfs_xattr_init(struct super_block *s, int mount_flags) 997{ 998 int err = 0; 999 struct dentry *privroot = REISERFS_SB(s)->priv_root; 1000 1001 err = xattr_mount_check(s); 1002 if (err) 1003 goto error; 1004 1005 if (d_really_is_negative(privroot) && !(mount_flags & SB_RDONLY)) { 1006 inode_lock(d_inode(s->s_root)); 1007 err = create_privroot(REISERFS_SB(s)->priv_root); 1008 inode_unlock(d_inode(s->s_root)); 1009 } 1010 1011 if (d_really_is_positive(privroot)) { 1012 inode_lock(d_inode(privroot)); 1013 if (!REISERFS_SB(s)->xattr_root) { 1014 struct dentry *dentry; 1015 1016 dentry = lookup_one_len(XAROOT_NAME, privroot, 1017 strlen(XAROOT_NAME)); 1018 if (!IS_ERR(dentry)) 1019 REISERFS_SB(s)->xattr_root = dentry; 1020 else 1021 err = PTR_ERR(dentry); 1022 } 1023 inode_unlock(d_inode(privroot)); 1024 } 1025 1026error: 1027 if (err) { 1028 clear_bit(REISERFS_XATTRS_USER, &REISERFS_SB(s)->s_mount_opt); 1029 clear_bit(REISERFS_POSIXACL, &REISERFS_SB(s)->s_mount_opt); 1030 } 1031 1032 /* The super_block SB_POSIXACL must mirror the (no)acl mount option. */ 1033 if (reiserfs_posixacl(s)) 1034 s->s_flags |= SB_POSIXACL; 1035 else 1036 s->s_flags &= ~SB_POSIXACL; 1037 1038 return err; 1039} 1040