1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2017-2018 HUAWEI, Inc. 4 * https://www.huawei.com/ 5 * Copyright (C) 2021-2022, Alibaba Cloud 6 */ 7 #include <linux/security.h> 8 #include "xattr.h" 9 10 struct xattr_iter { 11 struct super_block *sb; 12 struct erofs_buf buf; 13 erofs_off_t pos; 14 void *kaddr; 15 }; 16 17 static int erofs_init_inode_xattrs(struct inode *inode) 18 { 19 struct erofs_inode *const vi = EROFS_I(inode); 20 struct xattr_iter it; 21 unsigned int i; 22 struct erofs_xattr_ibody_header *ih; 23 struct super_block *sb = inode->i_sb; 24 int ret = 0; 25 26 /* the most case is that xattrs of this inode are initialized. */ 27 if (test_bit(EROFS_I_EA_INITED_BIT, &vi->flags)) { 28 /* 29 * paired with smp_mb() at the end of the function to ensure 30 * fields will only be observed after the bit is set. 31 */ 32 smp_mb(); 33 return 0; 34 } 35 36 if (wait_on_bit_lock(&vi->flags, EROFS_I_BL_XATTR_BIT, TASK_KILLABLE)) 37 return -ERESTARTSYS; 38 39 /* someone has initialized xattrs for us? */ 40 if (test_bit(EROFS_I_EA_INITED_BIT, &vi->flags)) 41 goto out_unlock; 42 43 /* 44 * bypass all xattr operations if ->xattr_isize is not greater than 45 * sizeof(struct erofs_xattr_ibody_header), in detail: 46 * 1) it is not enough to contain erofs_xattr_ibody_header then 47 * ->xattr_isize should be 0 (it means no xattr); 48 * 2) it is just to contain erofs_xattr_ibody_header, which is on-disk 49 * undefined right now (maybe use later with some new sb feature). 50 */ 51 if (vi->xattr_isize == sizeof(struct erofs_xattr_ibody_header)) { 52 erofs_err(sb, 53 "xattr_isize %d of nid %llu is not supported yet", 54 vi->xattr_isize, vi->nid); 55 ret = -EOPNOTSUPP; 56 goto out_unlock; 57 } else if (vi->xattr_isize < sizeof(struct erofs_xattr_ibody_header)) { 58 if (vi->xattr_isize) { 59 erofs_err(sb, "bogus xattr ibody @ nid %llu", vi->nid); 60 DBG_BUGON(1); 61 ret = -EFSCORRUPTED; 62 goto out_unlock; /* xattr ondisk layout error */ 63 } 64 ret = -ENOATTR; 65 goto out_unlock; 66 } 67 68 it.buf = __EROFS_BUF_INITIALIZER; 69 erofs_init_metabuf(&it.buf, sb); 70 it.pos = erofs_iloc(inode) + vi->inode_isize; 71 72 /* read in shared xattr array (non-atomic, see kmalloc below) */ 73 it.kaddr = erofs_bread(&it.buf, erofs_blknr(sb, it.pos), EROFS_KMAP); 74 if (IS_ERR(it.kaddr)) { 75 ret = PTR_ERR(it.kaddr); 76 goto out_unlock; 77 } 78 79 ih = it.kaddr + erofs_blkoff(sb, it.pos); 80 vi->xattr_shared_count = ih->h_shared_count; 81 vi->xattr_shared_xattrs = kmalloc_array(vi->xattr_shared_count, 82 sizeof(uint), GFP_KERNEL); 83 if (!vi->xattr_shared_xattrs) { 84 erofs_put_metabuf(&it.buf); 85 ret = -ENOMEM; 86 goto out_unlock; 87 } 88 89 /* let's skip ibody header */ 90 it.pos += sizeof(struct erofs_xattr_ibody_header); 91 92 for (i = 0; i < vi->xattr_shared_count; ++i) { 93 it.kaddr = erofs_bread(&it.buf, erofs_blknr(sb, it.pos), 94 EROFS_KMAP); 95 if (IS_ERR(it.kaddr)) { 96 kfree(vi->xattr_shared_xattrs); 97 vi->xattr_shared_xattrs = NULL; 98 ret = PTR_ERR(it.kaddr); 99 goto out_unlock; 100 } 101 vi->xattr_shared_xattrs[i] = le32_to_cpu(*(__le32 *) 102 (it.kaddr + erofs_blkoff(sb, it.pos))); 103 it.pos += sizeof(__le32); 104 } 105 erofs_put_metabuf(&it.buf); 106 107 /* paired with smp_mb() at the beginning of the function. */ 108 smp_mb(); 109 set_bit(EROFS_I_EA_INITED_BIT, &vi->flags); 110 111 out_unlock: 112 clear_and_wake_up_bit(EROFS_I_BL_XATTR_BIT, &vi->flags); 113 return ret; 114 } 115 116 /* 117 * the general idea for these return values is 118 * if 0 is returned, go on processing the current xattr; 119 * 1 (> 0) is returned, skip this round to process the next xattr; 120 * -err (< 0) is returned, an error (maybe ENOXATTR) occurred 121 * and need to be handled 122 */ 123 struct xattr_iter_handlers { 124 int (*entry)(struct xattr_iter *_it, struct erofs_xattr_entry *entry); 125 int (*name)(struct xattr_iter *_it, unsigned int processed, char *buf, 126 unsigned int len); 127 int (*alloc_buffer)(struct xattr_iter *_it, unsigned int value_sz); 128 void (*value)(struct xattr_iter *_it, unsigned int processed, char *buf, 129 unsigned int len); 130 }; 131 132 static int inline_xattr_iter_begin(struct xattr_iter *it, 133 struct inode *inode) 134 { 135 struct erofs_inode *const vi = EROFS_I(inode); 136 unsigned int xattr_header_sz; 137 138 xattr_header_sz = sizeof(struct erofs_xattr_ibody_header) + 139 sizeof(u32) * vi->xattr_shared_count; 140 if (xattr_header_sz >= vi->xattr_isize) { 141 DBG_BUGON(xattr_header_sz > vi->xattr_isize); 142 return -ENOATTR; 143 } 144 145 it->pos = erofs_iloc(inode) + vi->inode_isize + xattr_header_sz; 146 it->kaddr = erofs_bread(&it->buf, erofs_blknr(it->sb, it->pos), 147 EROFS_KMAP); 148 if (IS_ERR(it->kaddr)) 149 return PTR_ERR(it->kaddr); 150 return vi->xattr_isize - xattr_header_sz; 151 } 152 153 /* 154 * Regardless of success or failure, `xattr_foreach' will end up with 155 * `pos' pointing to the next xattr item rather than an arbitrary position. 156 */ 157 static int xattr_foreach(struct xattr_iter *it, 158 const struct xattr_iter_handlers *op, 159 unsigned int *tlimit) 160 { 161 struct erofs_xattr_entry entry; 162 struct super_block *sb = it->sb; 163 unsigned int value_sz, processed, slice; 164 int err; 165 166 /* 0. fixup blkaddr, pos */ 167 it->kaddr = erofs_bread(&it->buf, erofs_blknr(sb, it->pos), EROFS_KMAP); 168 if (IS_ERR(it->kaddr)) 169 return PTR_ERR(it->kaddr); 170 171 /* 172 * 1. read xattr entry to the memory, 173 * since we do EROFS_XATTR_ALIGN 174 * therefore entry should be in the page 175 */ 176 entry = *(struct erofs_xattr_entry *) 177 (it->kaddr + erofs_blkoff(sb, it->pos)); 178 if (tlimit) { 179 unsigned int entry_sz = erofs_xattr_entry_size(&entry); 180 181 /* xattr on-disk corruption: xattr entry beyond xattr_isize */ 182 if (*tlimit < entry_sz) { 183 DBG_BUGON(1); 184 return -EFSCORRUPTED; 185 } 186 *tlimit -= entry_sz; 187 } 188 189 it->pos += sizeof(struct erofs_xattr_entry); 190 value_sz = le16_to_cpu(entry.e_value_size); 191 192 /* handle entry */ 193 err = op->entry(it, &entry); 194 if (err) { 195 it->pos += entry.e_name_len + value_sz; 196 goto out; 197 } 198 199 /* 2. handle xattr name (pos will finally be at the end of name) */ 200 processed = 0; 201 202 while (processed < entry.e_name_len) { 203 it->kaddr = erofs_bread(&it->buf, erofs_blknr(sb, it->pos), 204 EROFS_KMAP); 205 if (IS_ERR(it->kaddr)) { 206 err = PTR_ERR(it->kaddr); 207 goto out; 208 } 209 210 slice = min_t(unsigned int, 211 sb->s_blocksize - erofs_blkoff(sb, it->pos), 212 entry.e_name_len - processed); 213 214 /* handle name */ 215 err = op->name(it, processed, 216 it->kaddr + erofs_blkoff(sb, it->pos), slice); 217 if (err) { 218 it->pos += entry.e_name_len - processed + value_sz; 219 goto out; 220 } 221 222 it->pos += slice; 223 processed += slice; 224 } 225 226 /* 3. handle xattr value */ 227 processed = 0; 228 229 if (op->alloc_buffer) { 230 err = op->alloc_buffer(it, value_sz); 231 if (err) { 232 it->pos += value_sz; 233 goto out; 234 } 235 } 236 237 while (processed < value_sz) { 238 it->kaddr = erofs_bread(&it->buf, erofs_blknr(sb, it->pos), 239 EROFS_KMAP); 240 if (IS_ERR(it->kaddr)) { 241 err = PTR_ERR(it->kaddr); 242 goto out; 243 } 244 245 slice = min_t(unsigned int, 246 sb->s_blocksize - erofs_blkoff(sb, it->pos), 247 value_sz - processed); 248 op->value(it, processed, it->kaddr + erofs_blkoff(sb, it->pos), 249 slice); 250 it->pos += slice; 251 processed += slice; 252 } 253 254 out: 255 /* xattrs should be 4-byte aligned (on-disk constraint) */ 256 it->pos = EROFS_XATTR_ALIGN(it->pos); 257 return err < 0 ? err : 0; 258 } 259 260 struct getxattr_iter { 261 struct xattr_iter it; 262 263 char *buffer; 264 int buffer_size, index, infix_len; 265 struct qstr name; 266 }; 267 268 static int erofs_xattr_long_entrymatch(struct getxattr_iter *it, 269 struct erofs_xattr_entry *entry) 270 { 271 struct erofs_sb_info *sbi = EROFS_SB(it->it.sb); 272 struct erofs_xattr_prefix_item *pf = sbi->xattr_prefixes + 273 (entry->e_name_index & EROFS_XATTR_LONG_PREFIX_MASK); 274 275 if (pf >= sbi->xattr_prefixes + sbi->xattr_prefix_count) 276 return -ENOATTR; 277 278 if (it->index != pf->prefix->base_index || 279 it->name.len != entry->e_name_len + pf->infix_len) 280 return -ENOATTR; 281 282 if (memcmp(it->name.name, pf->prefix->infix, pf->infix_len)) 283 return -ENOATTR; 284 285 it->infix_len = pf->infix_len; 286 return 0; 287 } 288 289 static int xattr_entrymatch(struct xattr_iter *_it, 290 struct erofs_xattr_entry *entry) 291 { 292 struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it); 293 294 /* should also match the infix for long name prefixes */ 295 if (entry->e_name_index & EROFS_XATTR_LONG_PREFIX) 296 return erofs_xattr_long_entrymatch(it, entry); 297 298 if (it->index != entry->e_name_index || 299 it->name.len != entry->e_name_len) 300 return -ENOATTR; 301 it->infix_len = 0; 302 return 0; 303 } 304 305 static int xattr_namematch(struct xattr_iter *_it, 306 unsigned int processed, char *buf, unsigned int len) 307 { 308 struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it); 309 310 if (memcmp(buf, it->name.name + it->infix_len + processed, len)) 311 return -ENOATTR; 312 return 0; 313 } 314 315 static int xattr_checkbuffer(struct xattr_iter *_it, 316 unsigned int value_sz) 317 { 318 struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it); 319 int err = it->buffer_size < value_sz ? -ERANGE : 0; 320 321 it->buffer_size = value_sz; 322 return !it->buffer ? 1 : err; 323 } 324 325 static void xattr_copyvalue(struct xattr_iter *_it, 326 unsigned int processed, 327 char *buf, unsigned int len) 328 { 329 struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it); 330 331 memcpy(it->buffer + processed, buf, len); 332 } 333 334 static const struct xattr_iter_handlers find_xattr_handlers = { 335 .entry = xattr_entrymatch, 336 .name = xattr_namematch, 337 .alloc_buffer = xattr_checkbuffer, 338 .value = xattr_copyvalue 339 }; 340 341 static int inline_getxattr(struct inode *inode, struct getxattr_iter *it) 342 { 343 int ret; 344 unsigned int remaining; 345 346 ret = inline_xattr_iter_begin(&it->it, inode); 347 if (ret < 0) 348 return ret; 349 350 remaining = ret; 351 while (remaining) { 352 ret = xattr_foreach(&it->it, &find_xattr_handlers, &remaining); 353 if (ret != -ENOATTR) 354 break; 355 } 356 return ret ? ret : it->buffer_size; 357 } 358 359 static int shared_getxattr(struct inode *inode, struct getxattr_iter *it) 360 { 361 struct erofs_inode *const vi = EROFS_I(inode); 362 struct super_block *const sb = it->it.sb; 363 struct erofs_sb_info *sbi = EROFS_SB(sb); 364 unsigned int i; 365 int ret = -ENOATTR; 366 367 for (i = 0; i < vi->xattr_shared_count; ++i) { 368 it->it.pos = erofs_pos(sb, sbi->xattr_blkaddr) + 369 vi->xattr_shared_xattrs[i] * sizeof(__le32); 370 it->it.kaddr = erofs_bread(&it->it.buf, 371 erofs_blknr(sb, it->it.pos), EROFS_KMAP); 372 if (IS_ERR(it->it.kaddr)) 373 return PTR_ERR(it->it.kaddr); 374 375 ret = xattr_foreach(&it->it, &find_xattr_handlers, NULL); 376 if (ret != -ENOATTR) 377 break; 378 } 379 return ret ? ret : it->buffer_size; 380 } 381 382 static bool erofs_xattr_user_list(struct dentry *dentry) 383 { 384 return test_opt(&EROFS_SB(dentry->d_sb)->opt, XATTR_USER); 385 } 386 387 static bool erofs_xattr_trusted_list(struct dentry *dentry) 388 { 389 return capable(CAP_SYS_ADMIN); 390 } 391 392 int erofs_getxattr(struct inode *inode, int index, 393 const char *name, 394 void *buffer, size_t buffer_size) 395 { 396 int ret; 397 struct getxattr_iter it; 398 399 if (!name) 400 return -EINVAL; 401 402 ret = erofs_init_inode_xattrs(inode); 403 if (ret) 404 return ret; 405 406 it.index = index; 407 it.name.len = strlen(name); 408 if (it.name.len > EROFS_NAME_LEN) 409 return -ERANGE; 410 411 it.it.sb = inode->i_sb; 412 it.it.buf = __EROFS_BUF_INITIALIZER; 413 erofs_init_metabuf(&it.it.buf, it.it.sb); 414 it.name.name = name; 415 416 it.buffer = buffer; 417 it.buffer_size = buffer_size; 418 419 ret = inline_getxattr(inode, &it); 420 if (ret == -ENOATTR) 421 ret = shared_getxattr(inode, &it); 422 erofs_put_metabuf(&it.it.buf); 423 return ret; 424 } 425 426 static int erofs_xattr_generic_get(const struct xattr_handler *handler, 427 struct dentry *unused, struct inode *inode, 428 const char *name, void *buffer, size_t size) 429 { 430 if (handler->flags == EROFS_XATTR_INDEX_USER && 431 !test_opt(&EROFS_I_SB(inode)->opt, XATTR_USER)) 432 return -EOPNOTSUPP; 433 434 return erofs_getxattr(inode, handler->flags, name, buffer, size); 435 } 436 437 const struct xattr_handler erofs_xattr_user_handler = { 438 .prefix = XATTR_USER_PREFIX, 439 .flags = EROFS_XATTR_INDEX_USER, 440 .list = erofs_xattr_user_list, 441 .get = erofs_xattr_generic_get, 442 }; 443 444 const struct xattr_handler erofs_xattr_trusted_handler = { 445 .prefix = XATTR_TRUSTED_PREFIX, 446 .flags = EROFS_XATTR_INDEX_TRUSTED, 447 .list = erofs_xattr_trusted_list, 448 .get = erofs_xattr_generic_get, 449 }; 450 451 #ifdef CONFIG_EROFS_FS_SECURITY 452 const struct xattr_handler __maybe_unused erofs_xattr_security_handler = { 453 .prefix = XATTR_SECURITY_PREFIX, 454 .flags = EROFS_XATTR_INDEX_SECURITY, 455 .get = erofs_xattr_generic_get, 456 }; 457 #endif 458 459 const struct xattr_handler *erofs_xattr_handlers[] = { 460 &erofs_xattr_user_handler, 461 &erofs_xattr_trusted_handler, 462 #ifdef CONFIG_EROFS_FS_SECURITY 463 &erofs_xattr_security_handler, 464 #endif 465 NULL, 466 }; 467 468 struct listxattr_iter { 469 struct xattr_iter it; 470 471 struct dentry *dentry; 472 char *buffer; 473 int buffer_size, buffer_ofs; 474 }; 475 476 static int xattr_entrylist(struct xattr_iter *_it, 477 struct erofs_xattr_entry *entry) 478 { 479 struct listxattr_iter *it = 480 container_of(_it, struct listxattr_iter, it); 481 unsigned int base_index = entry->e_name_index; 482 unsigned int prefix_len, infix_len = 0; 483 const char *prefix, *infix = NULL; 484 485 if (entry->e_name_index & EROFS_XATTR_LONG_PREFIX) { 486 struct erofs_sb_info *sbi = EROFS_SB(_it->sb); 487 struct erofs_xattr_prefix_item *pf = sbi->xattr_prefixes + 488 (entry->e_name_index & EROFS_XATTR_LONG_PREFIX_MASK); 489 490 if (pf >= sbi->xattr_prefixes + sbi->xattr_prefix_count) 491 return 1; 492 infix = pf->prefix->infix; 493 infix_len = pf->infix_len; 494 base_index = pf->prefix->base_index; 495 } 496 497 prefix = erofs_xattr_prefix(base_index, it->dentry); 498 if (!prefix) 499 return 1; 500 prefix_len = strlen(prefix); 501 502 if (!it->buffer) { 503 it->buffer_ofs += prefix_len + infix_len + 504 entry->e_name_len + 1; 505 return 1; 506 } 507 508 if (it->buffer_ofs + prefix_len + infix_len + 509 + entry->e_name_len + 1 > it->buffer_size) 510 return -ERANGE; 511 512 memcpy(it->buffer + it->buffer_ofs, prefix, prefix_len); 513 memcpy(it->buffer + it->buffer_ofs + prefix_len, infix, infix_len); 514 it->buffer_ofs += prefix_len + infix_len; 515 return 0; 516 } 517 518 static int xattr_namelist(struct xattr_iter *_it, 519 unsigned int processed, char *buf, unsigned int len) 520 { 521 struct listxattr_iter *it = 522 container_of(_it, struct listxattr_iter, it); 523 524 memcpy(it->buffer + it->buffer_ofs, buf, len); 525 it->buffer_ofs += len; 526 return 0; 527 } 528 529 static int xattr_skipvalue(struct xattr_iter *_it, 530 unsigned int value_sz) 531 { 532 struct listxattr_iter *it = 533 container_of(_it, struct listxattr_iter, it); 534 535 it->buffer[it->buffer_ofs++] = '\0'; 536 return 1; 537 } 538 539 static const struct xattr_iter_handlers list_xattr_handlers = { 540 .entry = xattr_entrylist, 541 .name = xattr_namelist, 542 .alloc_buffer = xattr_skipvalue, 543 .value = NULL 544 }; 545 546 static int inline_listxattr(struct listxattr_iter *it) 547 { 548 int ret; 549 unsigned int remaining; 550 551 ret = inline_xattr_iter_begin(&it->it, d_inode(it->dentry)); 552 if (ret < 0) 553 return ret; 554 555 remaining = ret; 556 while (remaining) { 557 ret = xattr_foreach(&it->it, &list_xattr_handlers, &remaining); 558 if (ret) 559 break; 560 } 561 return ret ? ret : it->buffer_ofs; 562 } 563 564 static int shared_listxattr(struct listxattr_iter *it) 565 { 566 struct inode *const inode = d_inode(it->dentry); 567 struct erofs_inode *const vi = EROFS_I(inode); 568 struct super_block *const sb = it->it.sb; 569 struct erofs_sb_info *sbi = EROFS_SB(sb); 570 unsigned int i; 571 int ret = 0; 572 573 for (i = 0; i < vi->xattr_shared_count; ++i) { 574 it->it.pos = erofs_pos(sb, sbi->xattr_blkaddr) + 575 vi->xattr_shared_xattrs[i] * sizeof(__le32); 576 it->it.kaddr = erofs_bread(&it->it.buf, 577 erofs_blknr(sb, it->it.pos), EROFS_KMAP); 578 if (IS_ERR(it->it.kaddr)) 579 return PTR_ERR(it->it.kaddr); 580 581 ret = xattr_foreach(&it->it, &list_xattr_handlers, NULL); 582 if (ret) 583 break; 584 } 585 return ret ? ret : it->buffer_ofs; 586 } 587 588 ssize_t erofs_listxattr(struct dentry *dentry, 589 char *buffer, size_t buffer_size) 590 { 591 int ret; 592 struct listxattr_iter it; 593 594 ret = erofs_init_inode_xattrs(d_inode(dentry)); 595 if (ret == -ENOATTR) 596 return 0; 597 if (ret) 598 return ret; 599 600 it.it.sb = dentry->d_sb; 601 it.it.buf = __EROFS_BUF_INITIALIZER; 602 erofs_init_metabuf(&it.it.buf, it.it.sb); 603 it.dentry = dentry; 604 it.buffer = buffer; 605 it.buffer_size = buffer_size; 606 it.buffer_ofs = 0; 607 608 ret = inline_listxattr(&it); 609 if (ret >= 0 || ret == -ENOATTR) 610 ret = shared_listxattr(&it); 611 erofs_put_metabuf(&it.it.buf); 612 return ret; 613 } 614 615 void erofs_xattr_prefixes_cleanup(struct super_block *sb) 616 { 617 struct erofs_sb_info *sbi = EROFS_SB(sb); 618 int i; 619 620 if (sbi->xattr_prefixes) { 621 for (i = 0; i < sbi->xattr_prefix_count; i++) 622 kfree(sbi->xattr_prefixes[i].prefix); 623 kfree(sbi->xattr_prefixes); 624 sbi->xattr_prefixes = NULL; 625 } 626 } 627 628 int erofs_xattr_prefixes_init(struct super_block *sb) 629 { 630 struct erofs_sb_info *sbi = EROFS_SB(sb); 631 struct erofs_buf buf = __EROFS_BUF_INITIALIZER; 632 erofs_off_t pos = (erofs_off_t)sbi->xattr_prefix_start << 2; 633 struct erofs_xattr_prefix_item *pfs; 634 int ret = 0, i, len; 635 636 if (!sbi->xattr_prefix_count) 637 return 0; 638 639 pfs = kzalloc(sbi->xattr_prefix_count * sizeof(*pfs), GFP_KERNEL); 640 if (!pfs) 641 return -ENOMEM; 642 643 if (sbi->packed_inode) 644 buf.inode = sbi->packed_inode; 645 else 646 erofs_init_metabuf(&buf, sb); 647 648 for (i = 0; i < sbi->xattr_prefix_count; i++) { 649 void *ptr = erofs_read_metadata(sb, &buf, &pos, &len); 650 651 if (IS_ERR(ptr)) { 652 ret = PTR_ERR(ptr); 653 break; 654 } else if (len < sizeof(*pfs->prefix) || 655 len > EROFS_NAME_LEN + sizeof(*pfs->prefix)) { 656 kfree(ptr); 657 ret = -EFSCORRUPTED; 658 break; 659 } 660 pfs[i].prefix = ptr; 661 pfs[i].infix_len = len - sizeof(struct erofs_xattr_long_prefix); 662 } 663 664 erofs_put_metabuf(&buf); 665 sbi->xattr_prefixes = pfs; 666 if (ret) 667 erofs_xattr_prefixes_cleanup(sb); 668 return ret; 669 } 670 671 #ifdef CONFIG_EROFS_FS_POSIX_ACL 672 struct posix_acl *erofs_get_acl(struct inode *inode, int type, bool rcu) 673 { 674 struct posix_acl *acl; 675 int prefix, rc; 676 char *value = NULL; 677 678 if (rcu) 679 return ERR_PTR(-ECHILD); 680 681 switch (type) { 682 case ACL_TYPE_ACCESS: 683 prefix = EROFS_XATTR_INDEX_POSIX_ACL_ACCESS; 684 break; 685 case ACL_TYPE_DEFAULT: 686 prefix = EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT; 687 break; 688 default: 689 return ERR_PTR(-EINVAL); 690 } 691 692 rc = erofs_getxattr(inode, prefix, "", NULL, 0); 693 if (rc > 0) { 694 value = kmalloc(rc, GFP_KERNEL); 695 if (!value) 696 return ERR_PTR(-ENOMEM); 697 rc = erofs_getxattr(inode, prefix, "", value, rc); 698 } 699 700 if (rc == -ENOATTR) 701 acl = NULL; 702 else if (rc < 0) 703 acl = ERR_PTR(rc); 704 else 705 acl = posix_acl_from_xattr(&init_user_ns, value, rc); 706 kfree(value); 707 return acl; 708 } 709 #endif 710