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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (C) 2017-2018 HUAWEI, Inc.4 * https://www.huawei.com/5 * Copyright (C) 2021-2022, Alibaba Cloud6 */7#include <linux/security.h>8#include <linux/xxhash.h>9#include "xattr.h"10 11struct 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 28static 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 ensure41 * 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 than56 * sizeof(struct erofs_xattr_ibody_header), in detail:57 * 1) it is not enough to contain erofs_xattr_ibody_header then58 * ->xattr_isize should be 0 (it means no xattr);59 * 2) it is just to contain erofs_xattr_ibody_header, which is on-disk60 * 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, 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;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, it.pos, EROFS_KMAP);106 if (IS_ERR(it.kaddr)) {107 kfree(vi->xattr_shared_xattrs);108 vi->xattr_shared_xattrs = NULL;109 ret = PTR_ERR(it.kaddr);110 goto out_unlock;111 }112 vi->xattr_shared_xattrs[i] = le32_to_cpu(*(__le32 *)it.kaddr);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 121out_unlock:122 clear_and_wake_up_bit(EROFS_I_BL_XATTR_BIT, &vi->flags);123 return ret;124}125 126static bool erofs_xattr_user_list(struct dentry *dentry)127{128 return test_opt(&EROFS_SB(dentry->d_sb)->opt, XATTR_USER);129}130 131static bool erofs_xattr_trusted_list(struct dentry *dentry)132{133 return capable(CAP_SYS_ADMIN);134}135 136static 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 147const 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 154const 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_SECURITY162const 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#endif168 169const struct xattr_handler * const erofs_xattr_handlers[] = {170 &erofs_xattr_user_handler,171 &erofs_xattr_trusted_handler,172#ifdef CONFIG_EROFS_FS_SECURITY173 &erofs_xattr_security_handler,174#endif175 NULL,176};177 178static 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, it->pos, EROFS_KMAP);187 if (IS_ERR(it->kaddr))188 return PTR_ERR(it->kaddr);189 190 src = it->kaddr;191 slice = min_t(unsigned int, sb->s_blocksize -192 erofs_blkoff(sb, it->pos), len - processed);193 memcpy(it->buffer + it->buffer_ofs, src, slice);194 it->buffer_ofs += slice;195 it->pos += slice;196 }197 return 0;198}199 200static int erofs_listxattr_foreach(struct erofs_xattr_iter *it)201{202 struct erofs_xattr_entry entry;203 unsigned int base_index, name_total, prefix_len, infix_len = 0;204 const char *prefix, *infix = NULL;205 int err;206 207 /* 1. handle xattr entry */208 entry = *(struct erofs_xattr_entry *)it->kaddr;209 it->pos += sizeof(struct erofs_xattr_entry);210 211 base_index = entry.e_name_index;212 if (entry.e_name_index & EROFS_XATTR_LONG_PREFIX) {213 struct erofs_sb_info *sbi = EROFS_SB(it->sb);214 struct erofs_xattr_prefix_item *pf = sbi->xattr_prefixes +215 (entry.e_name_index & EROFS_XATTR_LONG_PREFIX_MASK);216 217 if (pf >= sbi->xattr_prefixes + sbi->xattr_prefix_count)218 return 0;219 infix = pf->prefix->infix;220 infix_len = pf->infix_len;221 base_index = pf->prefix->base_index;222 }223 224 prefix = erofs_xattr_prefix(base_index, it->dentry);225 if (!prefix)226 return 0;227 prefix_len = strlen(prefix);228 name_total = prefix_len + infix_len + entry.e_name_len + 1;229 230 if (!it->buffer) {231 it->buffer_ofs += name_total;232 return 0;233 }234 235 if (it->buffer_ofs + name_total > it->buffer_size)236 return -ERANGE;237 238 memcpy(it->buffer + it->buffer_ofs, prefix, prefix_len);239 memcpy(it->buffer + it->buffer_ofs + prefix_len, infix, infix_len);240 it->buffer_ofs += prefix_len + infix_len;241 242 /* 2. handle xattr name */243 err = erofs_xattr_copy_to_buffer(it, entry.e_name_len);244 if (err)245 return err;246 247 it->buffer[it->buffer_ofs++] = '\0';248 return 0;249}250 251static int erofs_getxattr_foreach(struct erofs_xattr_iter *it)252{253 struct super_block *sb = it->sb;254 struct erofs_xattr_entry entry;255 unsigned int slice, processed, value_sz;256 257 /* 1. handle xattr entry */258 entry = *(struct erofs_xattr_entry *)it->kaddr;259 it->pos += sizeof(struct erofs_xattr_entry);260 value_sz = le16_to_cpu(entry.e_value_size);261 262 /* should also match the infix for long name prefixes */263 if (entry.e_name_index & EROFS_XATTR_LONG_PREFIX) {264 struct erofs_sb_info *sbi = EROFS_SB(sb);265 struct erofs_xattr_prefix_item *pf = sbi->xattr_prefixes +266 (entry.e_name_index & EROFS_XATTR_LONG_PREFIX_MASK);267 268 if (pf >= sbi->xattr_prefixes + sbi->xattr_prefix_count)269 return -ENOATTR;270 271 if (it->index != pf->prefix->base_index ||272 it->name.len != entry.e_name_len + pf->infix_len)273 return -ENOATTR;274 275 if (memcmp(it->name.name, pf->prefix->infix, pf->infix_len))276 return -ENOATTR;277 278 it->infix_len = pf->infix_len;279 } else {280 if (it->index != entry.e_name_index ||281 it->name.len != entry.e_name_len)282 return -ENOATTR;283 284 it->infix_len = 0;285 }286 287 /* 2. handle xattr name */288 for (processed = 0; processed < entry.e_name_len; processed += slice) {289 it->kaddr = erofs_bread(&it->buf, it->pos, EROFS_KMAP);290 if (IS_ERR(it->kaddr))291 return PTR_ERR(it->kaddr);292 293 slice = min_t(unsigned int,294 sb->s_blocksize - erofs_blkoff(sb, it->pos),295 entry.e_name_len - processed);296 if (memcmp(it->name.name + it->infix_len + processed,297 it->kaddr, slice))298 return -ENOATTR;299 it->pos += slice;300 }301 302 /* 3. handle xattr value */303 if (!it->buffer) {304 it->buffer_ofs = value_sz;305 return 0;306 }307 308 if (it->buffer_size < value_sz)309 return -ERANGE;310 311 return erofs_xattr_copy_to_buffer(it, value_sz);312}313 314static int erofs_xattr_iter_inline(struct erofs_xattr_iter *it,315 struct inode *inode, bool getxattr)316{317 struct erofs_inode *const vi = EROFS_I(inode);318 unsigned int xattr_header_sz, remaining, entry_sz;319 erofs_off_t next_pos;320 int ret;321 322 xattr_header_sz = sizeof(struct erofs_xattr_ibody_header) +323 sizeof(u32) * vi->xattr_shared_count;324 if (xattr_header_sz >= vi->xattr_isize) {325 DBG_BUGON(xattr_header_sz > vi->xattr_isize);326 return -ENOATTR;327 }328 329 remaining = vi->xattr_isize - xattr_header_sz;330 it->pos = erofs_iloc(inode) + vi->inode_isize + xattr_header_sz;331 332 while (remaining) {333 it->kaddr = erofs_bread(&it->buf, it->pos, EROFS_KMAP);334 if (IS_ERR(it->kaddr))335 return PTR_ERR(it->kaddr);336 337 entry_sz = erofs_xattr_entry_size(it->kaddr);338 /* xattr on-disk corruption: xattr entry beyond xattr_isize */339 if (remaining < entry_sz) {340 DBG_BUGON(1);341 return -EFSCORRUPTED;342 }343 remaining -= entry_sz;344 next_pos = it->pos + entry_sz;345 346 if (getxattr)347 ret = erofs_getxattr_foreach(it);348 else349 ret = erofs_listxattr_foreach(it);350 if ((getxattr && ret != -ENOATTR) || (!getxattr && ret))351 break;352 353 it->pos = next_pos;354 }355 return ret;356}357 358static int erofs_xattr_iter_shared(struct erofs_xattr_iter *it,359 struct inode *inode, bool getxattr)360{361 struct erofs_inode *const vi = EROFS_I(inode);362 struct super_block *const sb = 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->pos = erofs_pos(sb, sbi->xattr_blkaddr) +369 vi->xattr_shared_xattrs[i] * sizeof(__le32);370 it->kaddr = erofs_bread(&it->buf, it->pos, EROFS_KMAP);371 if (IS_ERR(it->kaddr))372 return PTR_ERR(it->kaddr);373 374 if (getxattr)375 ret = erofs_getxattr_foreach(it);376 else377 ret = erofs_listxattr_foreach(it);378 if ((getxattr && ret != -ENOATTR) || (!getxattr && ret))379 break;380 }381 return ret;382}383 384int erofs_getxattr(struct inode *inode, int index, const char *name,385 void *buffer, size_t buffer_size)386{387 int ret;388 unsigned int hashbit;389 struct erofs_xattr_iter it;390 struct erofs_inode *vi = EROFS_I(inode);391 struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);392 393 if (!name)394 return -EINVAL;395 396 ret = erofs_init_inode_xattrs(inode);397 if (ret)398 return ret;399 400 /* reserved flag is non-zero if there's any change of on-disk format */401 if (erofs_sb_has_xattr_filter(sbi) && !sbi->xattr_filter_reserved) {402 hashbit = xxh32(name, strlen(name),403 EROFS_XATTR_FILTER_SEED + index);404 hashbit &= EROFS_XATTR_FILTER_BITS - 1;405 if (vi->xattr_name_filter & (1U << hashbit))406 return -ENOATTR;407 }408 409 it.index = index;410 it.name = (struct qstr)QSTR_INIT(name, strlen(name));411 if (it.name.len > EROFS_NAME_LEN)412 return -ERANGE;413 414 it.sb = inode->i_sb;415 it.buf = __EROFS_BUF_INITIALIZER;416 erofs_init_metabuf(&it.buf, it.sb);417 it.buffer = buffer;418 it.buffer_size = buffer_size;419 it.buffer_ofs = 0;420 421 ret = erofs_xattr_iter_inline(&it, inode, true);422 if (ret == -ENOATTR)423 ret = erofs_xattr_iter_shared(&it, inode, true);424 erofs_put_metabuf(&it.buf);425 return ret ? ret : it.buffer_ofs;426}427 428ssize_t erofs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)429{430 int ret;431 struct erofs_xattr_iter it;432 struct inode *inode = d_inode(dentry);433 434 ret = erofs_init_inode_xattrs(inode);435 if (ret == -ENOATTR)436 return 0;437 if (ret)438 return ret;439 440 it.sb = dentry->d_sb;441 it.buf = __EROFS_BUF_INITIALIZER;442 erofs_init_metabuf(&it.buf, it.sb);443 it.dentry = dentry;444 it.buffer = buffer;445 it.buffer_size = buffer_size;446 it.buffer_ofs = 0;447 448 ret = erofs_xattr_iter_inline(&it, inode, false);449 if (!ret || ret == -ENOATTR)450 ret = erofs_xattr_iter_shared(&it, inode, false);451 if (ret == -ENOATTR)452 ret = 0;453 erofs_put_metabuf(&it.buf);454 return ret ? ret : it.buffer_ofs;455}456 457void erofs_xattr_prefixes_cleanup(struct super_block *sb)458{459 struct erofs_sb_info *sbi = EROFS_SB(sb);460 int i;461 462 if (sbi->xattr_prefixes) {463 for (i = 0; i < sbi->xattr_prefix_count; i++)464 kfree(sbi->xattr_prefixes[i].prefix);465 kfree(sbi->xattr_prefixes);466 sbi->xattr_prefixes = NULL;467 }468}469 470int erofs_xattr_prefixes_init(struct super_block *sb)471{472 struct erofs_sb_info *sbi = EROFS_SB(sb);473 struct erofs_buf buf = __EROFS_BUF_INITIALIZER;474 erofs_off_t pos = (erofs_off_t)sbi->xattr_prefix_start << 2;475 struct erofs_xattr_prefix_item *pfs;476 int ret = 0, i, len;477 478 if (!sbi->xattr_prefix_count)479 return 0;480 481 pfs = kzalloc(sbi->xattr_prefix_count * sizeof(*pfs), GFP_KERNEL);482 if (!pfs)483 return -ENOMEM;484 485 if (sbi->packed_inode)486 buf.mapping = sbi->packed_inode->i_mapping;487 else488 erofs_init_metabuf(&buf, sb);489 490 for (i = 0; i < sbi->xattr_prefix_count; i++) {491 void *ptr = erofs_read_metadata(sb, &buf, &pos, &len);492 493 if (IS_ERR(ptr)) {494 ret = PTR_ERR(ptr);495 break;496 } else if (len < sizeof(*pfs->prefix) ||497 len > EROFS_NAME_LEN + sizeof(*pfs->prefix)) {498 kfree(ptr);499 ret = -EFSCORRUPTED;500 break;501 }502 pfs[i].prefix = ptr;503 pfs[i].infix_len = len - sizeof(struct erofs_xattr_long_prefix);504 }505 506 erofs_put_metabuf(&buf);507 sbi->xattr_prefixes = pfs;508 if (ret)509 erofs_xattr_prefixes_cleanup(sb);510 return ret;511}512 513#ifdef CONFIG_EROFS_FS_POSIX_ACL514struct posix_acl *erofs_get_acl(struct inode *inode, int type, bool rcu)515{516 struct posix_acl *acl;517 int prefix, rc;518 char *value = NULL;519 520 if (rcu)521 return ERR_PTR(-ECHILD);522 523 switch (type) {524 case ACL_TYPE_ACCESS:525 prefix = EROFS_XATTR_INDEX_POSIX_ACL_ACCESS;526 break;527 case ACL_TYPE_DEFAULT:528 prefix = EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT;529 break;530 default:531 return ERR_PTR(-EINVAL);532 }533 534 rc = erofs_getxattr(inode, prefix, "", NULL, 0);535 if (rc > 0) {536 value = kmalloc(rc, GFP_KERNEL);537 if (!value)538 return ERR_PTR(-ENOMEM);539 rc = erofs_getxattr(inode, prefix, "", value, rc);540 }541 542 if (rc == -ENOATTR)543 acl = NULL;544 else if (rc < 0)545 acl = ERR_PTR(rc);546 else547 acl = posix_acl_from_xattr(&init_user_ns, value, rc);548 kfree(value);549 return acl;550}551#endif552