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