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 = -ENODATA; 76 goto out_unlock; 77 } 78 79 it.buf = __EROFS_BUF_INITIALIZER; 80 ret = erofs_init_metabuf(&it.buf, sb, erofs_inode_in_metabox(inode)); 81 if (ret) 82 goto out_unlock; 83 it.pos = erofs_iloc(inode) + vi->inode_isize; 84 85 /* read in shared xattr array (non-atomic, see kmalloc below) */ 86 it.kaddr = erofs_bread(&it.buf, it.pos, true); 87 if (IS_ERR(it.kaddr)) { 88 ret = PTR_ERR(it.kaddr); 89 goto out_unlock; 90 } 91 92 ih = it.kaddr; 93 vi->xattr_name_filter = le32_to_cpu(ih->h_name_filter); 94 vi->xattr_shared_count = ih->h_shared_count; 95 vi->xattr_shared_xattrs = kmalloc_array(vi->xattr_shared_count, 96 sizeof(uint), GFP_KERNEL); 97 if (!vi->xattr_shared_xattrs) { 98 erofs_put_metabuf(&it.buf); 99 ret = -ENOMEM; 100 goto out_unlock; 101 } 102 103 /* let's skip ibody header */ 104 it.pos += sizeof(struct erofs_xattr_ibody_header); 105 106 for (i = 0; i < vi->xattr_shared_count; ++i) { 107 it.kaddr = erofs_bread(&it.buf, it.pos, true); 108 if (IS_ERR(it.kaddr)) { 109 kfree(vi->xattr_shared_xattrs); 110 vi->xattr_shared_xattrs = NULL; 111 ret = PTR_ERR(it.kaddr); 112 goto out_unlock; 113 } 114 vi->xattr_shared_xattrs[i] = le32_to_cpu(*(__le32 *)it.kaddr); 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, it->pos, true); 189 if (IS_ERR(it->kaddr)) 190 return PTR_ERR(it->kaddr); 191 192 src = it->kaddr; 193 slice = min_t(unsigned int, sb->s_blocksize - 194 erofs_blkoff(sb, it->pos), len - processed); 195 memcpy(it->buffer + it->buffer_ofs, src, slice); 196 it->buffer_ofs += slice; 197 it->pos += slice; 198 } 199 return 0; 200 } 201 202 static int erofs_listxattr_foreach(struct erofs_xattr_iter *it) 203 { 204 struct erofs_xattr_entry entry; 205 unsigned int base_index, name_total, prefix_len, infix_len = 0; 206 const char *prefix, *infix = NULL; 207 int err; 208 209 /* 1. handle xattr entry */ 210 entry = *(struct erofs_xattr_entry *)it->kaddr; 211 it->pos += sizeof(struct erofs_xattr_entry); 212 213 base_index = entry.e_name_index; 214 if (entry.e_name_index & EROFS_XATTR_LONG_PREFIX) { 215 struct erofs_sb_info *sbi = EROFS_SB(it->sb); 216 struct erofs_xattr_prefix_item *pf = sbi->xattr_prefixes + 217 (entry.e_name_index & EROFS_XATTR_LONG_PREFIX_MASK); 218 219 if (pf >= sbi->xattr_prefixes + sbi->xattr_prefix_count) 220 return 0; 221 infix = pf->prefix->infix; 222 infix_len = pf->infix_len; 223 base_index = pf->prefix->base_index; 224 } 225 226 prefix = erofs_xattr_prefix(base_index, it->dentry); 227 if (!prefix) 228 return 0; 229 prefix_len = strlen(prefix); 230 name_total = prefix_len + infix_len + entry.e_name_len + 1; 231 232 if (!it->buffer) { 233 it->buffer_ofs += name_total; 234 return 0; 235 } 236 237 if (it->buffer_ofs + name_total > it->buffer_size) 238 return -ERANGE; 239 240 memcpy(it->buffer + it->buffer_ofs, prefix, prefix_len); 241 memcpy(it->buffer + it->buffer_ofs + prefix_len, infix, infix_len); 242 it->buffer_ofs += prefix_len + infix_len; 243 244 /* 2. handle xattr name */ 245 err = erofs_xattr_copy_to_buffer(it, entry.e_name_len); 246 if (err) 247 return err; 248 249 it->buffer[it->buffer_ofs++] = '\0'; 250 return 0; 251 } 252 253 static int erofs_getxattr_foreach(struct erofs_xattr_iter *it) 254 { 255 struct super_block *sb = it->sb; 256 struct erofs_xattr_entry entry; 257 unsigned int slice, processed, value_sz; 258 259 /* 1. handle xattr entry */ 260 entry = *(struct erofs_xattr_entry *)it->kaddr; 261 it->pos += sizeof(struct erofs_xattr_entry); 262 value_sz = le16_to_cpu(entry.e_value_size); 263 264 /* should also match the infix for long name prefixes */ 265 if (entry.e_name_index & EROFS_XATTR_LONG_PREFIX) { 266 struct erofs_sb_info *sbi = EROFS_SB(sb); 267 struct erofs_xattr_prefix_item *pf = sbi->xattr_prefixes + 268 (entry.e_name_index & EROFS_XATTR_LONG_PREFIX_MASK); 269 270 if (pf >= sbi->xattr_prefixes + sbi->xattr_prefix_count) 271 return -ENODATA; 272 273 if (it->index != pf->prefix->base_index || 274 it->name.len != entry.e_name_len + pf->infix_len) 275 return -ENODATA; 276 277 if (memcmp(it->name.name, pf->prefix->infix, pf->infix_len)) 278 return -ENODATA; 279 280 it->infix_len = pf->infix_len; 281 } else { 282 if (it->index != entry.e_name_index || 283 it->name.len != entry.e_name_len) 284 return -ENODATA; 285 286 it->infix_len = 0; 287 } 288 289 /* 2. handle xattr name */ 290 for (processed = 0; processed < entry.e_name_len; processed += slice) { 291 it->kaddr = erofs_bread(&it->buf, it->pos, true); 292 if (IS_ERR(it->kaddr)) 293 return PTR_ERR(it->kaddr); 294 295 slice = min_t(unsigned int, 296 sb->s_blocksize - erofs_blkoff(sb, it->pos), 297 entry.e_name_len - processed); 298 if (memcmp(it->name.name + it->infix_len + processed, 299 it->kaddr, slice)) 300 return -ENODATA; 301 it->pos += slice; 302 } 303 304 /* 3. handle xattr value */ 305 if (!it->buffer) { 306 it->buffer_ofs = value_sz; 307 return 0; 308 } 309 310 if (it->buffer_size < value_sz) 311 return -ERANGE; 312 313 return erofs_xattr_copy_to_buffer(it, value_sz); 314 } 315 316 static int erofs_xattr_iter_inline(struct erofs_xattr_iter *it, 317 struct inode *inode, bool getxattr) 318 { 319 struct erofs_inode *const vi = EROFS_I(inode); 320 unsigned int xattr_header_sz, remaining, entry_sz; 321 erofs_off_t next_pos; 322 int ret; 323 324 xattr_header_sz = sizeof(struct erofs_xattr_ibody_header) + 325 sizeof(u32) * vi->xattr_shared_count; 326 if (xattr_header_sz >= vi->xattr_isize) { 327 DBG_BUGON(xattr_header_sz > vi->xattr_isize); 328 return -ENODATA; 329 } 330 331 ret = erofs_init_metabuf(&it->buf, it->sb, erofs_inode_in_metabox(inode)); 332 if (ret) 333 return ret; 334 remaining = vi->xattr_isize - xattr_header_sz; 335 it->pos = erofs_iloc(inode) + vi->inode_isize + xattr_header_sz; 336 337 while (remaining) { 338 it->kaddr = erofs_bread(&it->buf, it->pos, true); 339 if (IS_ERR(it->kaddr)) 340 return PTR_ERR(it->kaddr); 341 342 entry_sz = erofs_xattr_entry_size(it->kaddr); 343 /* xattr on-disk corruption: xattr entry beyond xattr_isize */ 344 if (remaining < entry_sz) { 345 DBG_BUGON(1); 346 return -EFSCORRUPTED; 347 } 348 remaining -= entry_sz; 349 next_pos = it->pos + entry_sz; 350 351 if (getxattr) 352 ret = erofs_getxattr_foreach(it); 353 else 354 ret = erofs_listxattr_foreach(it); 355 if ((getxattr && ret != -ENODATA) || (!getxattr && ret)) 356 break; 357 358 it->pos = next_pos; 359 } 360 return ret; 361 } 362 363 static int erofs_xattr_iter_shared(struct erofs_xattr_iter *it, 364 struct inode *inode, bool getxattr) 365 { 366 struct erofs_inode *const vi = EROFS_I(inode); 367 struct super_block *const sb = it->sb; 368 struct erofs_sb_info *sbi = EROFS_SB(sb); 369 unsigned int i = 0; 370 int ret; 371 372 ret = erofs_init_metabuf(&it->buf, sb, 373 erofs_sb_has_shared_ea_in_metabox(sbi)); 374 if (ret) 375 return ret; 376 377 while (i < vi->xattr_shared_count) { 378 it->pos = erofs_pos(sb, sbi->xattr_blkaddr) + 379 vi->xattr_shared_xattrs[i++] * sizeof(__le32); 380 it->kaddr = erofs_bread(&it->buf, it->pos, true); 381 if (IS_ERR(it->kaddr)) 382 return PTR_ERR(it->kaddr); 383 384 if (getxattr) 385 ret = erofs_getxattr_foreach(it); 386 else 387 ret = erofs_listxattr_foreach(it); 388 if ((getxattr && ret != -ENODATA) || (!getxattr && ret)) 389 break; 390 } 391 return i ? ret : -ENODATA; 392 } 393 394 int erofs_getxattr(struct inode *inode, int index, const char *name, 395 void *buffer, size_t buffer_size) 396 { 397 int ret; 398 unsigned int hashbit; 399 struct erofs_xattr_iter it; 400 struct erofs_inode *vi = EROFS_I(inode); 401 struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb); 402 403 if (!name) 404 return -EINVAL; 405 406 ret = erofs_init_inode_xattrs(inode); 407 if (ret) 408 return ret; 409 410 /* reserved flag is non-zero if there's any change of on-disk format */ 411 if (erofs_sb_has_xattr_filter(sbi) && !sbi->xattr_filter_reserved) { 412 hashbit = xxh32(name, strlen(name), 413 EROFS_XATTR_FILTER_SEED + index); 414 hashbit &= EROFS_XATTR_FILTER_BITS - 1; 415 if (vi->xattr_name_filter & (1U << hashbit)) 416 return -ENODATA; 417 } 418 419 it.index = index; 420 it.name = QSTR(name); 421 if (it.name.len > EROFS_NAME_LEN) 422 return -ERANGE; 423 424 it.sb = inode->i_sb; 425 it.buf = __EROFS_BUF_INITIALIZER; 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 == -ENODATA) 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 == -ENODATA) 445 return 0; 446 if (ret) 447 return ret; 448 449 it.sb = dentry->d_sb; 450 it.buf = __EROFS_BUF_INITIALIZER; 451 it.dentry = dentry; 452 it.buffer = buffer; 453 it.buffer_size = buffer_size; 454 it.buffer_ofs = 0; 455 456 ret = erofs_xattr_iter_inline(&it, inode, false); 457 if (!ret || ret == -ENODATA) 458 ret = erofs_xattr_iter_shared(&it, inode, false); 459 if (ret == -ENODATA) 460 ret = 0; 461 erofs_put_metabuf(&it.buf); 462 return ret ? ret : it.buffer_ofs; 463 } 464 465 void erofs_xattr_prefixes_cleanup(struct super_block *sb) 466 { 467 struct erofs_sb_info *sbi = EROFS_SB(sb); 468 int i; 469 470 if (sbi->xattr_prefixes) { 471 for (i = 0; i < sbi->xattr_prefix_count; i++) 472 kfree(sbi->xattr_prefixes[i].prefix); 473 kfree(sbi->xattr_prefixes); 474 sbi->xattr_prefixes = NULL; 475 } 476 } 477 478 int erofs_xattr_prefixes_init(struct super_block *sb) 479 { 480 struct erofs_sb_info *sbi = EROFS_SB(sb); 481 struct erofs_buf buf = __EROFS_BUF_INITIALIZER; 482 erofs_off_t pos = (erofs_off_t)sbi->xattr_prefix_start << 2; 483 struct erofs_xattr_prefix_item *pfs; 484 int ret = 0, i, len; 485 486 if (!sbi->xattr_prefix_count) 487 return 0; 488 489 pfs = kcalloc(sbi->xattr_prefix_count, sizeof(*pfs), GFP_KERNEL); 490 if (!pfs) 491 return -ENOMEM; 492 493 if (sbi->packed_inode) 494 buf.mapping = sbi->packed_inode->i_mapping; 495 else 496 (void)erofs_init_metabuf(&buf, sb, false); 497 498 for (i = 0; i < sbi->xattr_prefix_count; i++) { 499 void *ptr = erofs_read_metadata(sb, &buf, &pos, &len); 500 501 if (IS_ERR(ptr)) { 502 ret = PTR_ERR(ptr); 503 break; 504 } else if (len < sizeof(*pfs->prefix) || 505 len > EROFS_NAME_LEN + sizeof(*pfs->prefix)) { 506 kfree(ptr); 507 ret = -EFSCORRUPTED; 508 break; 509 } 510 pfs[i].prefix = ptr; 511 pfs[i].infix_len = len - sizeof(struct erofs_xattr_long_prefix); 512 } 513 514 erofs_put_metabuf(&buf); 515 sbi->xattr_prefixes = pfs; 516 if (ret) 517 erofs_xattr_prefixes_cleanup(sb); 518 return ret; 519 } 520 521 #ifdef CONFIG_EROFS_FS_POSIX_ACL 522 struct posix_acl *erofs_get_acl(struct inode *inode, int type, bool rcu) 523 { 524 struct posix_acl *acl; 525 int prefix, rc; 526 char *value = NULL; 527 528 if (rcu) 529 return ERR_PTR(-ECHILD); 530 531 switch (type) { 532 case ACL_TYPE_ACCESS: 533 prefix = EROFS_XATTR_INDEX_POSIX_ACL_ACCESS; 534 break; 535 case ACL_TYPE_DEFAULT: 536 prefix = EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT; 537 break; 538 default: 539 return ERR_PTR(-EINVAL); 540 } 541 542 rc = erofs_getxattr(inode, prefix, "", NULL, 0); 543 if (rc > 0) { 544 value = kmalloc(rc, GFP_KERNEL); 545 if (!value) 546 return ERR_PTR(-ENOMEM); 547 rc = erofs_getxattr(inode, prefix, "", value, rc); 548 } 549 550 if (rc == -ENODATA) 551 acl = NULL; 552 else if (rc < 0) 553 acl = ERR_PTR(rc); 554 else 555 acl = posix_acl_from_xattr(&init_user_ns, value, rc); 556 kfree(value); 557 return acl; 558 } 559 #endif 560