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 <linux/xxhash.h> 9 #include "xattr.h" 10 11 struct erofs_xattr_iter { 12 struct super_block *sb; 13 struct erofs_buf buf; 14 erofs_off_t pos; 15 void *kaddr; 16 17 char *buffer; 18 int buffer_size, buffer_ofs; 19 20 /* getxattr */ 21 int index, infix_len; 22 struct qstr name; 23 24 /* listxattr */ 25 struct dentry *dentry; 26 }; 27 28 static int erofs_init_inode_xattrs(struct inode *inode) 29 { 30 struct erofs_inode *const vi = EROFS_I(inode); 31 struct erofs_xattr_iter it; 32 unsigned int i; 33 struct erofs_xattr_ibody_header *ih; 34 struct super_block *sb = inode->i_sb; 35 int ret = 0; 36 37 /* the most case is that xattrs of this inode are initialized. */ 38 if (test_bit(EROFS_I_EA_INITED_BIT, &vi->flags)) { 39 /* 40 * paired with smp_mb() at the end of the function to ensure 41 * fields will only be observed after the bit is set. 42 */ 43 smp_mb(); 44 return 0; 45 } 46 47 if (wait_on_bit_lock(&vi->flags, EROFS_I_BL_XATTR_BIT, TASK_KILLABLE)) 48 return -ERESTARTSYS; 49 50 /* someone has initialized xattrs for us? */ 51 if (test_bit(EROFS_I_EA_INITED_BIT, &vi->flags)) 52 goto out_unlock; 53 54 /* 55 * bypass all xattr operations if ->xattr_isize is not greater than 56 * sizeof(struct erofs_xattr_ibody_header), in detail: 57 * 1) it is not enough to contain erofs_xattr_ibody_header then 58 * ->xattr_isize should be 0 (it means no xattr); 59 * 2) it is just to contain erofs_xattr_ibody_header, which is on-disk 60 * undefined right now (maybe use later with some new sb feature). 61 */ 62 if (vi->xattr_isize == sizeof(struct erofs_xattr_ibody_header)) { 63 erofs_err(sb, 64 "xattr_isize %d of nid %llu is not supported yet", 65 vi->xattr_isize, vi->nid); 66 ret = -EOPNOTSUPP; 67 goto out_unlock; 68 } else if (vi->xattr_isize < sizeof(struct erofs_xattr_ibody_header)) { 69 if (vi->xattr_isize) { 70 erofs_err(sb, "bogus xattr ibody @ nid %llu", vi->nid); 71 DBG_BUGON(1); 72 ret = -EFSCORRUPTED; 73 goto out_unlock; /* xattr ondisk layout error */ 74 } 75 ret = -ENOATTR; 76 goto out_unlock; 77 } 78 79 it.buf = __EROFS_BUF_INITIALIZER; 80 erofs_init_metabuf(&it.buf, sb); 81 it.pos = erofs_iloc(inode) + vi->inode_isize; 82 83 /* read in shared xattr array (non-atomic, see kmalloc below) */ 84 it.kaddr = erofs_bread(&it.buf, erofs_blknr(sb, it.pos), EROFS_KMAP); 85 if (IS_ERR(it.kaddr)) { 86 ret = PTR_ERR(it.kaddr); 87 goto out_unlock; 88 } 89 90 ih = it.kaddr + erofs_blkoff(sb, it.pos); 91 vi->xattr_name_filter = le32_to_cpu(ih->h_name_filter); 92 vi->xattr_shared_count = ih->h_shared_count; 93 vi->xattr_shared_xattrs = kmalloc_array(vi->xattr_shared_count, 94 sizeof(uint), GFP_KERNEL); 95 if (!vi->xattr_shared_xattrs) { 96 erofs_put_metabuf(&it.buf); 97 ret = -ENOMEM; 98 goto out_unlock; 99 } 100 101 /* let's skip ibody header */ 102 it.pos += sizeof(struct erofs_xattr_ibody_header); 103 104 for (i = 0; i < vi->xattr_shared_count; ++i) { 105 it.kaddr = erofs_bread(&it.buf, erofs_blknr(sb, it.pos), 106 EROFS_KMAP); 107 if (IS_ERR(it.kaddr)) { 108 kfree(vi->xattr_shared_xattrs); 109 vi->xattr_shared_xattrs = NULL; 110 ret = PTR_ERR(it.kaddr); 111 goto out_unlock; 112 } 113 vi->xattr_shared_xattrs[i] = le32_to_cpu(*(__le32 *) 114 (it.kaddr + erofs_blkoff(sb, it.pos))); 115 it.pos += sizeof(__le32); 116 } 117 erofs_put_metabuf(&it.buf); 118 119 /* paired with smp_mb() at the beginning of the function. */ 120 smp_mb(); 121 set_bit(EROFS_I_EA_INITED_BIT, &vi->flags); 122 123 out_unlock: 124 clear_and_wake_up_bit(EROFS_I_BL_XATTR_BIT, &vi->flags); 125 return ret; 126 } 127 128 static bool erofs_xattr_user_list(struct dentry *dentry) 129 { 130 return test_opt(&EROFS_SB(dentry->d_sb)->opt, XATTR_USER); 131 } 132 133 static bool erofs_xattr_trusted_list(struct dentry *dentry) 134 { 135 return capable(CAP_SYS_ADMIN); 136 } 137 138 static int erofs_xattr_generic_get(const struct xattr_handler *handler, 139 struct dentry *unused, struct inode *inode, 140 const char *name, void *buffer, size_t size) 141 { 142 if (handler->flags == EROFS_XATTR_INDEX_USER && 143 !test_opt(&EROFS_I_SB(inode)->opt, XATTR_USER)) 144 return -EOPNOTSUPP; 145 146 return erofs_getxattr(inode, handler->flags, name, buffer, size); 147 } 148 149 const struct xattr_handler erofs_xattr_user_handler = { 150 .prefix = XATTR_USER_PREFIX, 151 .flags = EROFS_XATTR_INDEX_USER, 152 .list = erofs_xattr_user_list, 153 .get = erofs_xattr_generic_get, 154 }; 155 156 const struct xattr_handler erofs_xattr_trusted_handler = { 157 .prefix = XATTR_TRUSTED_PREFIX, 158 .flags = EROFS_XATTR_INDEX_TRUSTED, 159 .list = erofs_xattr_trusted_list, 160 .get = erofs_xattr_generic_get, 161 }; 162 163 #ifdef CONFIG_EROFS_FS_SECURITY 164 const struct xattr_handler __maybe_unused erofs_xattr_security_handler = { 165 .prefix = XATTR_SECURITY_PREFIX, 166 .flags = EROFS_XATTR_INDEX_SECURITY, 167 .get = erofs_xattr_generic_get, 168 }; 169 #endif 170 171 const struct xattr_handler * const erofs_xattr_handlers[] = { 172 &erofs_xattr_user_handler, 173 &erofs_xattr_trusted_handler, 174 #ifdef CONFIG_EROFS_FS_SECURITY 175 &erofs_xattr_security_handler, 176 #endif 177 NULL, 178 }; 179 180 static int erofs_xattr_copy_to_buffer(struct erofs_xattr_iter *it, 181 unsigned int len) 182 { 183 unsigned int slice, processed; 184 struct super_block *sb = it->sb; 185 void *src; 186 187 for (processed = 0; processed < len; processed += slice) { 188 it->kaddr = erofs_bread(&it->buf, erofs_blknr(sb, it->pos), 189 EROFS_KMAP); 190 if (IS_ERR(it->kaddr)) 191 return PTR_ERR(it->kaddr); 192 193 src = it->kaddr + erofs_blkoff(sb, it->pos); 194 slice = min_t(unsigned int, sb->s_blocksize - 195 erofs_blkoff(sb, it->pos), len - processed); 196 memcpy(it->buffer + it->buffer_ofs, src, slice); 197 it->buffer_ofs += slice; 198 it->pos += slice; 199 } 200 return 0; 201 } 202 203 static int erofs_listxattr_foreach(struct erofs_xattr_iter *it) 204 { 205 struct erofs_xattr_entry entry; 206 unsigned int base_index, name_total, prefix_len, infix_len = 0; 207 const char *prefix, *infix = NULL; 208 int err; 209 210 /* 1. handle xattr entry */ 211 entry = *(struct erofs_xattr_entry *) 212 (it->kaddr + erofs_blkoff(it->sb, it->pos)); 213 it->pos += sizeof(struct erofs_xattr_entry); 214 215 base_index = entry.e_name_index; 216 if (entry.e_name_index & EROFS_XATTR_LONG_PREFIX) { 217 struct erofs_sb_info *sbi = EROFS_SB(it->sb); 218 struct erofs_xattr_prefix_item *pf = sbi->xattr_prefixes + 219 (entry.e_name_index & EROFS_XATTR_LONG_PREFIX_MASK); 220 221 if (pf >= sbi->xattr_prefixes + sbi->xattr_prefix_count) 222 return 0; 223 infix = pf->prefix->infix; 224 infix_len = pf->infix_len; 225 base_index = pf->prefix->base_index; 226 } 227 228 prefix = erofs_xattr_prefix(base_index, it->dentry); 229 if (!prefix) 230 return 0; 231 prefix_len = strlen(prefix); 232 name_total = prefix_len + infix_len + entry.e_name_len + 1; 233 234 if (!it->buffer) { 235 it->buffer_ofs += name_total; 236 return 0; 237 } 238 239 if (it->buffer_ofs + name_total > it->buffer_size) 240 return -ERANGE; 241 242 memcpy(it->buffer + it->buffer_ofs, prefix, prefix_len); 243 memcpy(it->buffer + it->buffer_ofs + prefix_len, infix, infix_len); 244 it->buffer_ofs += prefix_len + infix_len; 245 246 /* 2. handle xattr name */ 247 err = erofs_xattr_copy_to_buffer(it, entry.e_name_len); 248 if (err) 249 return err; 250 251 it->buffer[it->buffer_ofs++] = '\0'; 252 return 0; 253 } 254 255 static int erofs_getxattr_foreach(struct erofs_xattr_iter *it) 256 { 257 struct super_block *sb = it->sb; 258 struct erofs_xattr_entry entry; 259 unsigned int slice, processed, value_sz; 260 261 /* 1. handle xattr entry */ 262 entry = *(struct erofs_xattr_entry *) 263 (it->kaddr + erofs_blkoff(sb, it->pos)); 264 it->pos += sizeof(struct erofs_xattr_entry); 265 value_sz = le16_to_cpu(entry.e_value_size); 266 267 /* should also match the infix for long name prefixes */ 268 if (entry.e_name_index & EROFS_XATTR_LONG_PREFIX) { 269 struct erofs_sb_info *sbi = EROFS_SB(sb); 270 struct erofs_xattr_prefix_item *pf = sbi->xattr_prefixes + 271 (entry.e_name_index & EROFS_XATTR_LONG_PREFIX_MASK); 272 273 if (pf >= sbi->xattr_prefixes + sbi->xattr_prefix_count) 274 return -ENOATTR; 275 276 if (it->index != pf->prefix->base_index || 277 it->name.len != entry.e_name_len + pf->infix_len) 278 return -ENOATTR; 279 280 if (memcmp(it->name.name, pf->prefix->infix, pf->infix_len)) 281 return -ENOATTR; 282 283 it->infix_len = pf->infix_len; 284 } else { 285 if (it->index != entry.e_name_index || 286 it->name.len != entry.e_name_len) 287 return -ENOATTR; 288 289 it->infix_len = 0; 290 } 291 292 /* 2. handle xattr name */ 293 for (processed = 0; processed < entry.e_name_len; processed += slice) { 294 it->kaddr = erofs_bread(&it->buf, erofs_blknr(sb, it->pos), 295 EROFS_KMAP); 296 if (IS_ERR(it->kaddr)) 297 return PTR_ERR(it->kaddr); 298 299 slice = min_t(unsigned int, 300 sb->s_blocksize - erofs_blkoff(sb, it->pos), 301 entry.e_name_len - processed); 302 if (memcmp(it->name.name + it->infix_len + processed, 303 it->kaddr + erofs_blkoff(sb, it->pos), slice)) 304 return -ENOATTR; 305 it->pos += slice; 306 } 307 308 /* 3. handle xattr value */ 309 if (!it->buffer) { 310 it->buffer_ofs = value_sz; 311 return 0; 312 } 313 314 if (it->buffer_size < value_sz) 315 return -ERANGE; 316 317 return erofs_xattr_copy_to_buffer(it, value_sz); 318 } 319 320 static int erofs_xattr_iter_inline(struct erofs_xattr_iter *it, 321 struct inode *inode, bool getxattr) 322 { 323 struct erofs_inode *const vi = EROFS_I(inode); 324 unsigned int xattr_header_sz, remaining, entry_sz; 325 erofs_off_t next_pos; 326 int ret; 327 328 xattr_header_sz = sizeof(struct erofs_xattr_ibody_header) + 329 sizeof(u32) * vi->xattr_shared_count; 330 if (xattr_header_sz >= vi->xattr_isize) { 331 DBG_BUGON(xattr_header_sz > vi->xattr_isize); 332 return -ENOATTR; 333 } 334 335 remaining = vi->xattr_isize - xattr_header_sz; 336 it->pos = erofs_iloc(inode) + vi->inode_isize + xattr_header_sz; 337 338 while (remaining) { 339 it->kaddr = erofs_bread(&it->buf, erofs_blknr(it->sb, it->pos), 340 EROFS_KMAP); 341 if (IS_ERR(it->kaddr)) 342 return PTR_ERR(it->kaddr); 343 344 entry_sz = erofs_xattr_entry_size(it->kaddr + 345 erofs_blkoff(it->sb, it->pos)); 346 /* xattr on-disk corruption: xattr entry beyond xattr_isize */ 347 if (remaining < entry_sz) { 348 DBG_BUGON(1); 349 return -EFSCORRUPTED; 350 } 351 remaining -= entry_sz; 352 next_pos = it->pos + entry_sz; 353 354 if (getxattr) 355 ret = erofs_getxattr_foreach(it); 356 else 357 ret = erofs_listxattr_foreach(it); 358 if ((getxattr && ret != -ENOATTR) || (!getxattr && ret)) 359 break; 360 361 it->pos = next_pos; 362 } 363 return ret; 364 } 365 366 static int erofs_xattr_iter_shared(struct erofs_xattr_iter *it, 367 struct inode *inode, bool getxattr) 368 { 369 struct erofs_inode *const vi = EROFS_I(inode); 370 struct super_block *const sb = it->sb; 371 struct erofs_sb_info *sbi = EROFS_SB(sb); 372 unsigned int i; 373 int ret = -ENOATTR; 374 375 for (i = 0; i < vi->xattr_shared_count; ++i) { 376 it->pos = erofs_pos(sb, sbi->xattr_blkaddr) + 377 vi->xattr_shared_xattrs[i] * sizeof(__le32); 378 it->kaddr = erofs_bread(&it->buf, erofs_blknr(sb, it->pos), 379 EROFS_KMAP); 380 if (IS_ERR(it->kaddr)) 381 return PTR_ERR(it->kaddr); 382 383 if (getxattr) 384 ret = erofs_getxattr_foreach(it); 385 else 386 ret = erofs_listxattr_foreach(it); 387 if ((getxattr && ret != -ENOATTR) || (!getxattr && ret)) 388 break; 389 } 390 return ret; 391 } 392 393 int erofs_getxattr(struct inode *inode, int index, const char *name, 394 void *buffer, size_t buffer_size) 395 { 396 int ret; 397 unsigned int hashbit; 398 struct erofs_xattr_iter it; 399 struct erofs_inode *vi = EROFS_I(inode); 400 struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb); 401 402 if (!name) 403 return -EINVAL; 404 405 ret = erofs_init_inode_xattrs(inode); 406 if (ret) 407 return ret; 408 409 /* reserved flag is non-zero if there's any change of on-disk format */ 410 if (erofs_sb_has_xattr_filter(sbi) && !sbi->xattr_filter_reserved) { 411 hashbit = xxh32(name, strlen(name), 412 EROFS_XATTR_FILTER_SEED + index); 413 hashbit &= EROFS_XATTR_FILTER_BITS - 1; 414 if (vi->xattr_name_filter & (1U << hashbit)) 415 return -ENOATTR; 416 } 417 418 it.index = index; 419 it.name = (struct qstr)QSTR_INIT(name, strlen(name)); 420 if (it.name.len > EROFS_NAME_LEN) 421 return -ERANGE; 422 423 it.sb = inode->i_sb; 424 it.buf = __EROFS_BUF_INITIALIZER; 425 erofs_init_metabuf(&it.buf, it.sb); 426 it.buffer = buffer; 427 it.buffer_size = buffer_size; 428 it.buffer_ofs = 0; 429 430 ret = erofs_xattr_iter_inline(&it, inode, true); 431 if (ret == -ENOATTR) 432 ret = erofs_xattr_iter_shared(&it, inode, true); 433 erofs_put_metabuf(&it.buf); 434 return ret ? ret : it.buffer_ofs; 435 } 436 437 ssize_t erofs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) 438 { 439 int ret; 440 struct erofs_xattr_iter it; 441 struct inode *inode = d_inode(dentry); 442 443 ret = erofs_init_inode_xattrs(inode); 444 if (ret == -ENOATTR) 445 return 0; 446 if (ret) 447 return ret; 448 449 it.sb = dentry->d_sb; 450 it.buf = __EROFS_BUF_INITIALIZER; 451 erofs_init_metabuf(&it.buf, it.sb); 452 it.dentry = dentry; 453 it.buffer = buffer; 454 it.buffer_size = buffer_size; 455 it.buffer_ofs = 0; 456 457 ret = erofs_xattr_iter_inline(&it, inode, false); 458 if (!ret || ret == -ENOATTR) 459 ret = erofs_xattr_iter_shared(&it, inode, false); 460 if (ret == -ENOATTR) 461 ret = 0; 462 erofs_put_metabuf(&it.buf); 463 return ret ? ret : it.buffer_ofs; 464 } 465 466 void erofs_xattr_prefixes_cleanup(struct super_block *sb) 467 { 468 struct erofs_sb_info *sbi = EROFS_SB(sb); 469 int i; 470 471 if (sbi->xattr_prefixes) { 472 for (i = 0; i < sbi->xattr_prefix_count; i++) 473 kfree(sbi->xattr_prefixes[i].prefix); 474 kfree(sbi->xattr_prefixes); 475 sbi->xattr_prefixes = NULL; 476 } 477 } 478 479 int erofs_xattr_prefixes_init(struct super_block *sb) 480 { 481 struct erofs_sb_info *sbi = EROFS_SB(sb); 482 struct erofs_buf buf = __EROFS_BUF_INITIALIZER; 483 erofs_off_t pos = (erofs_off_t)sbi->xattr_prefix_start << 2; 484 struct erofs_xattr_prefix_item *pfs; 485 int ret = 0, i, len; 486 487 if (!sbi->xattr_prefix_count) 488 return 0; 489 490 pfs = kzalloc(sbi->xattr_prefix_count * sizeof(*pfs), GFP_KERNEL); 491 if (!pfs) 492 return -ENOMEM; 493 494 if (sbi->packed_inode) 495 buf.inode = sbi->packed_inode; 496 else 497 erofs_init_metabuf(&buf, sb); 498 499 for (i = 0; i < sbi->xattr_prefix_count; i++) { 500 void *ptr = erofs_read_metadata(sb, &buf, &pos, &len); 501 502 if (IS_ERR(ptr)) { 503 ret = PTR_ERR(ptr); 504 break; 505 } else if (len < sizeof(*pfs->prefix) || 506 len > EROFS_NAME_LEN + sizeof(*pfs->prefix)) { 507 kfree(ptr); 508 ret = -EFSCORRUPTED; 509 break; 510 } 511 pfs[i].prefix = ptr; 512 pfs[i].infix_len = len - sizeof(struct erofs_xattr_long_prefix); 513 } 514 515 erofs_put_metabuf(&buf); 516 sbi->xattr_prefixes = pfs; 517 if (ret) 518 erofs_xattr_prefixes_cleanup(sb); 519 return ret; 520 } 521 522 #ifdef CONFIG_EROFS_FS_POSIX_ACL 523 struct posix_acl *erofs_get_acl(struct inode *inode, int type, bool rcu) 524 { 525 struct posix_acl *acl; 526 int prefix, rc; 527 char *value = NULL; 528 529 if (rcu) 530 return ERR_PTR(-ECHILD); 531 532 switch (type) { 533 case ACL_TYPE_ACCESS: 534 prefix = EROFS_XATTR_INDEX_POSIX_ACL_ACCESS; 535 break; 536 case ACL_TYPE_DEFAULT: 537 prefix = EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT; 538 break; 539 default: 540 return ERR_PTR(-EINVAL); 541 } 542 543 rc = erofs_getxattr(inode, prefix, "", NULL, 0); 544 if (rc > 0) { 545 value = kmalloc(rc, GFP_KERNEL); 546 if (!value) 547 return ERR_PTR(-ENOMEM); 548 rc = erofs_getxattr(inode, prefix, "", value, rc); 549 } 550 551 if (rc == -ENOATTR) 552 acl = NULL; 553 else if (rc < 0) 554 acl = ERR_PTR(rc); 555 else 556 acl = posix_acl_from_xattr(&init_user_ns, value, rc); 557 kfree(value); 558 return acl; 559 } 560 #endif 561