| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * Copyright (C) 2017-2018 HUAWEI, Inc. |
| * https://www.huawei.com/ |
| * Copyright (C) 2021-2022, Alibaba Cloud |
| */ |
| #include <linux/security.h> |
| #include <linux/xxhash.h> |
| #include "xattr.h" |
| |
| struct erofs_xattr_iter { |
| struct super_block *sb; |
| struct erofs_buf buf; |
| erofs_off_t pos; |
| void *kaddr; |
| |
| char *buffer; |
| int buffer_size, buffer_ofs; |
| |
| /* getxattr */ |
| int index, infix_len; |
| struct qstr name; |
| |
| /* listxattr */ |
| struct dentry *dentry; |
| }; |
| |
| static int erofs_init_inode_xattrs(struct inode *inode) |
| { |
| struct erofs_inode *const vi = EROFS_I(inode); |
| struct erofs_xattr_iter it; |
| unsigned int i; |
| struct erofs_xattr_ibody_header *ih; |
| struct super_block *sb = inode->i_sb; |
| int ret = 0; |
| |
| /* the most case is that xattrs of this inode are initialized. */ |
| if (test_bit(EROFS_I_EA_INITED_BIT, &vi->flags)) { |
| /* |
| * paired with smp_mb() at the end of the function to ensure |
| * fields will only be observed after the bit is set. |
| */ |
| smp_mb(); |
| return 0; |
| } |
| |
| if (wait_on_bit_lock(&vi->flags, EROFS_I_BL_XATTR_BIT, TASK_KILLABLE)) |
| return -ERESTARTSYS; |
| |
| /* someone has initialized xattrs for us? */ |
| if (test_bit(EROFS_I_EA_INITED_BIT, &vi->flags)) |
| goto out_unlock; |
| |
| /* |
| * bypass all xattr operations if ->xattr_isize is not greater than |
| * sizeof(struct erofs_xattr_ibody_header), in detail: |
| * 1) it is not enough to contain erofs_xattr_ibody_header then |
| * ->xattr_isize should be 0 (it means no xattr); |
| * 2) it is just to contain erofs_xattr_ibody_header, which is on-disk |
| * undefined right now (maybe use later with some new sb feature). |
| */ |
| if (vi->xattr_isize == sizeof(struct erofs_xattr_ibody_header)) { |
| erofs_err(sb, |
| "xattr_isize %d of nid %llu is not supported yet", |
| vi->xattr_isize, vi->nid); |
| ret = -EOPNOTSUPP; |
| goto out_unlock; |
| } else if (vi->xattr_isize < sizeof(struct erofs_xattr_ibody_header)) { |
| if (vi->xattr_isize) { |
| erofs_err(sb, "bogus xattr ibody @ nid %llu", vi->nid); |
| DBG_BUGON(1); |
| ret = -EFSCORRUPTED; |
| goto out_unlock; /* xattr ondisk layout error */ |
| } |
| ret = -ENOATTR; |
| goto out_unlock; |
| } |
| |
| it.buf = __EROFS_BUF_INITIALIZER; |
| erofs_init_metabuf(&it.buf, sb); |
| it.pos = erofs_iloc(inode) + vi->inode_isize; |
| |
| /* read in shared xattr array (non-atomic, see kmalloc below) */ |
| it.kaddr = erofs_bread(&it.buf, erofs_blknr(sb, it.pos), EROFS_KMAP); |
| if (IS_ERR(it.kaddr)) { |
| ret = PTR_ERR(it.kaddr); |
| goto out_unlock; |
| } |
| |
| ih = it.kaddr + erofs_blkoff(sb, it.pos); |
| vi->xattr_name_filter = le32_to_cpu(ih->h_name_filter); |
| vi->xattr_shared_count = ih->h_shared_count; |
| vi->xattr_shared_xattrs = kmalloc_array(vi->xattr_shared_count, |
| sizeof(uint), GFP_KERNEL); |
| if (!vi->xattr_shared_xattrs) { |
| erofs_put_metabuf(&it.buf); |
| ret = -ENOMEM; |
| goto out_unlock; |
| } |
| |
| /* let's skip ibody header */ |
| it.pos += sizeof(struct erofs_xattr_ibody_header); |
| |
| for (i = 0; i < vi->xattr_shared_count; ++i) { |
| it.kaddr = erofs_bread(&it.buf, erofs_blknr(sb, it.pos), |
| EROFS_KMAP); |
| if (IS_ERR(it.kaddr)) { |
| kfree(vi->xattr_shared_xattrs); |
| vi->xattr_shared_xattrs = NULL; |
| ret = PTR_ERR(it.kaddr); |
| goto out_unlock; |
| } |
| vi->xattr_shared_xattrs[i] = le32_to_cpu(*(__le32 *) |
| (it.kaddr + erofs_blkoff(sb, it.pos))); |
| it.pos += sizeof(__le32); |
| } |
| erofs_put_metabuf(&it.buf); |
| |
| /* paired with smp_mb() at the beginning of the function. */ |
| smp_mb(); |
| set_bit(EROFS_I_EA_INITED_BIT, &vi->flags); |
| |
| out_unlock: |
| clear_and_wake_up_bit(EROFS_I_BL_XATTR_BIT, &vi->flags); |
| return ret; |
| } |
| |
| static bool erofs_xattr_user_list(struct dentry *dentry) |
| { |
| return test_opt(&EROFS_SB(dentry->d_sb)->opt, XATTR_USER); |
| } |
| |
| static bool erofs_xattr_trusted_list(struct dentry *dentry) |
| { |
| return capable(CAP_SYS_ADMIN); |
| } |
| |
| static int erofs_xattr_generic_get(const struct xattr_handler *handler, |
| struct dentry *unused, struct inode *inode, |
| const char *name, void *buffer, size_t size) |
| { |
| if (handler->flags == EROFS_XATTR_INDEX_USER && |
| !test_opt(&EROFS_I_SB(inode)->opt, XATTR_USER)) |
| return -EOPNOTSUPP; |
| |
| return erofs_getxattr(inode, handler->flags, name, buffer, size); |
| } |
| |
| const struct xattr_handler erofs_xattr_user_handler = { |
| .prefix = XATTR_USER_PREFIX, |
| .flags = EROFS_XATTR_INDEX_USER, |
| .list = erofs_xattr_user_list, |
| .get = erofs_xattr_generic_get, |
| }; |
| |
| const struct xattr_handler erofs_xattr_trusted_handler = { |
| .prefix = XATTR_TRUSTED_PREFIX, |
| .flags = EROFS_XATTR_INDEX_TRUSTED, |
| .list = erofs_xattr_trusted_list, |
| .get = erofs_xattr_generic_get, |
| }; |
| |
| #ifdef CONFIG_EROFS_FS_SECURITY |
| const struct xattr_handler __maybe_unused erofs_xattr_security_handler = { |
| .prefix = XATTR_SECURITY_PREFIX, |
| .flags = EROFS_XATTR_INDEX_SECURITY, |
| .get = erofs_xattr_generic_get, |
| }; |
| #endif |
| |
| const struct xattr_handler *erofs_xattr_handlers[] = { |
| &erofs_xattr_user_handler, |
| &erofs_xattr_trusted_handler, |
| #ifdef CONFIG_EROFS_FS_SECURITY |
| &erofs_xattr_security_handler, |
| #endif |
| NULL, |
| }; |
| |
| static int erofs_xattr_copy_to_buffer(struct erofs_xattr_iter *it, |
| unsigned int len) |
| { |
| unsigned int slice, processed; |
| struct super_block *sb = it->sb; |
| void *src; |
| |
| for (processed = 0; processed < len; processed += slice) { |
| it->kaddr = erofs_bread(&it->buf, erofs_blknr(sb, it->pos), |
| EROFS_KMAP); |
| if (IS_ERR(it->kaddr)) |
| return PTR_ERR(it->kaddr); |
| |
| src = it->kaddr + erofs_blkoff(sb, it->pos); |
| slice = min_t(unsigned int, sb->s_blocksize - |
| erofs_blkoff(sb, it->pos), len - processed); |
| memcpy(it->buffer + it->buffer_ofs, src, slice); |
| it->buffer_ofs += slice; |
| it->pos += slice; |
| } |
| return 0; |
| } |
| |
| static int erofs_listxattr_foreach(struct erofs_xattr_iter *it) |
| { |
| struct erofs_xattr_entry entry; |
| unsigned int base_index, name_total, prefix_len, infix_len = 0; |
| const char *prefix, *infix = NULL; |
| int err; |
| |
| /* 1. handle xattr entry */ |
| entry = *(struct erofs_xattr_entry *) |
| (it->kaddr + erofs_blkoff(it->sb, it->pos)); |
| it->pos += sizeof(struct erofs_xattr_entry); |
| |
| base_index = entry.e_name_index; |
| if (entry.e_name_index & EROFS_XATTR_LONG_PREFIX) { |
| struct erofs_sb_info *sbi = EROFS_SB(it->sb); |
| struct erofs_xattr_prefix_item *pf = sbi->xattr_prefixes + |
| (entry.e_name_index & EROFS_XATTR_LONG_PREFIX_MASK); |
| |
| if (pf >= sbi->xattr_prefixes + sbi->xattr_prefix_count) |
| return 0; |
| infix = pf->prefix->infix; |
| infix_len = pf->infix_len; |
| base_index = pf->prefix->base_index; |
| } |
| |
| prefix = erofs_xattr_prefix(base_index, it->dentry); |
| if (!prefix) |
| return 0; |
| prefix_len = strlen(prefix); |
| name_total = prefix_len + infix_len + entry.e_name_len + 1; |
| |
| if (!it->buffer) { |
| it->buffer_ofs += name_total; |
| return 0; |
| } |
| |
| if (it->buffer_ofs + name_total > it->buffer_size) |
| return -ERANGE; |
| |
| memcpy(it->buffer + it->buffer_ofs, prefix, prefix_len); |
| memcpy(it->buffer + it->buffer_ofs + prefix_len, infix, infix_len); |
| it->buffer_ofs += prefix_len + infix_len; |
| |
| /* 2. handle xattr name */ |
| err = erofs_xattr_copy_to_buffer(it, entry.e_name_len); |
| if (err) |
| return err; |
| |
| it->buffer[it->buffer_ofs++] = '\0'; |
| return 0; |
| } |
| |
| static int erofs_getxattr_foreach(struct erofs_xattr_iter *it) |
| { |
| struct super_block *sb = it->sb; |
| struct erofs_xattr_entry entry; |
| unsigned int slice, processed, value_sz; |
| |
| /* 1. handle xattr entry */ |
| entry = *(struct erofs_xattr_entry *) |
| (it->kaddr + erofs_blkoff(sb, it->pos)); |
| it->pos += sizeof(struct erofs_xattr_entry); |
| value_sz = le16_to_cpu(entry.e_value_size); |
| |
| /* should also match the infix for long name prefixes */ |
| if (entry.e_name_index & EROFS_XATTR_LONG_PREFIX) { |
| struct erofs_sb_info *sbi = EROFS_SB(sb); |
| struct erofs_xattr_prefix_item *pf = sbi->xattr_prefixes + |
| (entry.e_name_index & EROFS_XATTR_LONG_PREFIX_MASK); |
| |
| if (pf >= sbi->xattr_prefixes + sbi->xattr_prefix_count) |
| return -ENOATTR; |
| |
| if (it->index != pf->prefix->base_index || |
| it->name.len != entry.e_name_len + pf->infix_len) |
| return -ENOATTR; |
| |
| if (memcmp(it->name.name, pf->prefix->infix, pf->infix_len)) |
| return -ENOATTR; |
| |
| it->infix_len = pf->infix_len; |
| } else { |
| if (it->index != entry.e_name_index || |
| it->name.len != entry.e_name_len) |
| return -ENOATTR; |
| |
| it->infix_len = 0; |
| } |
| |
| /* 2. handle xattr name */ |
| for (processed = 0; processed < entry.e_name_len; processed += slice) { |
| it->kaddr = erofs_bread(&it->buf, erofs_blknr(sb, it->pos), |
| EROFS_KMAP); |
| if (IS_ERR(it->kaddr)) |
| return PTR_ERR(it->kaddr); |
| |
| slice = min_t(unsigned int, |
| sb->s_blocksize - erofs_blkoff(sb, it->pos), |
| entry.e_name_len - processed); |
| if (memcmp(it->name.name + it->infix_len + processed, |
| it->kaddr + erofs_blkoff(sb, it->pos), slice)) |
| return -ENOATTR; |
| it->pos += slice; |
| } |
| |
| /* 3. handle xattr value */ |
| if (!it->buffer) { |
| it->buffer_ofs = value_sz; |
| return 0; |
| } |
| |
| if (it->buffer_size < value_sz) |
| return -ERANGE; |
| |
| return erofs_xattr_copy_to_buffer(it, value_sz); |
| } |
| |
| static int erofs_xattr_iter_inline(struct erofs_xattr_iter *it, |
| struct inode *inode, bool getxattr) |
| { |
| struct erofs_inode *const vi = EROFS_I(inode); |
| unsigned int xattr_header_sz, remaining, entry_sz; |
| erofs_off_t next_pos; |
| int ret; |
| |
| xattr_header_sz = sizeof(struct erofs_xattr_ibody_header) + |
| sizeof(u32) * vi->xattr_shared_count; |
| if (xattr_header_sz >= vi->xattr_isize) { |
| DBG_BUGON(xattr_header_sz > vi->xattr_isize); |
| return -ENOATTR; |
| } |
| |
| remaining = vi->xattr_isize - xattr_header_sz; |
| it->pos = erofs_iloc(inode) + vi->inode_isize + xattr_header_sz; |
| |
| while (remaining) { |
| it->kaddr = erofs_bread(&it->buf, erofs_blknr(it->sb, it->pos), |
| EROFS_KMAP); |
| if (IS_ERR(it->kaddr)) |
| return PTR_ERR(it->kaddr); |
| |
| entry_sz = erofs_xattr_entry_size(it->kaddr + |
| erofs_blkoff(it->sb, it->pos)); |
| /* xattr on-disk corruption: xattr entry beyond xattr_isize */ |
| if (remaining < entry_sz) { |
| DBG_BUGON(1); |
| return -EFSCORRUPTED; |
| } |
| remaining -= entry_sz; |
| next_pos = it->pos + entry_sz; |
| |
| if (getxattr) |
| ret = erofs_getxattr_foreach(it); |
| else |
| ret = erofs_listxattr_foreach(it); |
| if ((getxattr && ret != -ENOATTR) || (!getxattr && ret)) |
| break; |
| |
| it->pos = next_pos; |
| } |
| return ret; |
| } |
| |
| static int erofs_xattr_iter_shared(struct erofs_xattr_iter *it, |
| struct inode *inode, bool getxattr) |
| { |
| struct erofs_inode *const vi = EROFS_I(inode); |
| struct super_block *const sb = it->sb; |
| struct erofs_sb_info *sbi = EROFS_SB(sb); |
| unsigned int i; |
| int ret = -ENOATTR; |
| |
| for (i = 0; i < vi->xattr_shared_count; ++i) { |
| it->pos = erofs_pos(sb, sbi->xattr_blkaddr) + |
| vi->xattr_shared_xattrs[i] * sizeof(__le32); |
| it->kaddr = erofs_bread(&it->buf, erofs_blknr(sb, it->pos), |
| EROFS_KMAP); |
| if (IS_ERR(it->kaddr)) |
| return PTR_ERR(it->kaddr); |
| |
| if (getxattr) |
| ret = erofs_getxattr_foreach(it); |
| else |
| ret = erofs_listxattr_foreach(it); |
| if ((getxattr && ret != -ENOATTR) || (!getxattr && ret)) |
| break; |
| } |
| return ret; |
| } |
| |
| int erofs_getxattr(struct inode *inode, int index, const char *name, |
| void *buffer, size_t buffer_size) |
| { |
| int ret; |
| unsigned int hashbit; |
| struct erofs_xattr_iter it; |
| struct erofs_inode *vi = EROFS_I(inode); |
| struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb); |
| |
| if (!name) |
| return -EINVAL; |
| |
| ret = erofs_init_inode_xattrs(inode); |
| if (ret) |
| return ret; |
| |
| /* reserved flag is non-zero if there's any change of on-disk format */ |
| if (erofs_sb_has_xattr_filter(sbi) && !sbi->xattr_filter_reserved) { |
| hashbit = xxh32(name, strlen(name), |
| EROFS_XATTR_FILTER_SEED + index); |
| hashbit &= EROFS_XATTR_FILTER_BITS - 1; |
| if (vi->xattr_name_filter & (1U << hashbit)) |
| return -ENOATTR; |
| } |
| |
| it.index = index; |
| it.name = (struct qstr)QSTR_INIT(name, strlen(name)); |
| if (it.name.len > EROFS_NAME_LEN) |
| return -ERANGE; |
| |
| it.sb = inode->i_sb; |
| it.buf = __EROFS_BUF_INITIALIZER; |
| erofs_init_metabuf(&it.buf, it.sb); |
| it.buffer = buffer; |
| it.buffer_size = buffer_size; |
| it.buffer_ofs = 0; |
| |
| ret = erofs_xattr_iter_inline(&it, inode, true); |
| if (ret == -ENOATTR) |
| ret = erofs_xattr_iter_shared(&it, inode, true); |
| erofs_put_metabuf(&it.buf); |
| return ret ? ret : it.buffer_ofs; |
| } |
| |
| ssize_t erofs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) |
| { |
| int ret; |
| struct erofs_xattr_iter it; |
| struct inode *inode = d_inode(dentry); |
| |
| ret = erofs_init_inode_xattrs(inode); |
| if (ret == -ENOATTR) |
| return 0; |
| if (ret) |
| return ret; |
| |
| it.sb = dentry->d_sb; |
| it.buf = __EROFS_BUF_INITIALIZER; |
| erofs_init_metabuf(&it.buf, it.sb); |
| it.dentry = dentry; |
| it.buffer = buffer; |
| it.buffer_size = buffer_size; |
| it.buffer_ofs = 0; |
| |
| ret = erofs_xattr_iter_inline(&it, inode, false); |
| if (!ret || ret == -ENOATTR) |
| ret = erofs_xattr_iter_shared(&it, inode, false); |
| if (ret == -ENOATTR) |
| ret = 0; |
| erofs_put_metabuf(&it.buf); |
| return ret ? ret : it.buffer_ofs; |
| } |
| |
| void erofs_xattr_prefixes_cleanup(struct super_block *sb) |
| { |
| struct erofs_sb_info *sbi = EROFS_SB(sb); |
| int i; |
| |
| if (sbi->xattr_prefixes) { |
| for (i = 0; i < sbi->xattr_prefix_count; i++) |
| kfree(sbi->xattr_prefixes[i].prefix); |
| kfree(sbi->xattr_prefixes); |
| sbi->xattr_prefixes = NULL; |
| } |
| } |
| |
| int erofs_xattr_prefixes_init(struct super_block *sb) |
| { |
| struct erofs_sb_info *sbi = EROFS_SB(sb); |
| struct erofs_buf buf = __EROFS_BUF_INITIALIZER; |
| erofs_off_t pos = (erofs_off_t)sbi->xattr_prefix_start << 2; |
| struct erofs_xattr_prefix_item *pfs; |
| int ret = 0, i, len; |
| |
| if (!sbi->xattr_prefix_count) |
| return 0; |
| |
| pfs = kzalloc(sbi->xattr_prefix_count * sizeof(*pfs), GFP_KERNEL); |
| if (!pfs) |
| return -ENOMEM; |
| |
| if (sbi->packed_inode) |
| buf.inode = sbi->packed_inode; |
| else |
| erofs_init_metabuf(&buf, sb); |
| |
| for (i = 0; i < sbi->xattr_prefix_count; i++) { |
| void *ptr = erofs_read_metadata(sb, &buf, &pos, &len); |
| |
| if (IS_ERR(ptr)) { |
| ret = PTR_ERR(ptr); |
| break; |
| } else if (len < sizeof(*pfs->prefix) || |
| len > EROFS_NAME_LEN + sizeof(*pfs->prefix)) { |
| kfree(ptr); |
| ret = -EFSCORRUPTED; |
| break; |
| } |
| pfs[i].prefix = ptr; |
| pfs[i].infix_len = len - sizeof(struct erofs_xattr_long_prefix); |
| } |
| |
| erofs_put_metabuf(&buf); |
| sbi->xattr_prefixes = pfs; |
| if (ret) |
| erofs_xattr_prefixes_cleanup(sb); |
| return ret; |
| } |
| |
| #ifdef CONFIG_EROFS_FS_POSIX_ACL |
| struct posix_acl *erofs_get_acl(struct inode *inode, int type, bool rcu) |
| { |
| struct posix_acl *acl; |
| int prefix, rc; |
| char *value = NULL; |
| |
| if (rcu) |
| return ERR_PTR(-ECHILD); |
| |
| switch (type) { |
| case ACL_TYPE_ACCESS: |
| prefix = EROFS_XATTR_INDEX_POSIX_ACL_ACCESS; |
| break; |
| case ACL_TYPE_DEFAULT: |
| prefix = EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT; |
| break; |
| default: |
| return ERR_PTR(-EINVAL); |
| } |
| |
| rc = erofs_getxattr(inode, prefix, "", NULL, 0); |
| if (rc > 0) { |
| value = kmalloc(rc, GFP_KERNEL); |
| if (!value) |
| return ERR_PTR(-ENOMEM); |
| rc = erofs_getxattr(inode, prefix, "", value, rc); |
| } |
| |
| if (rc == -ENOATTR) |
| acl = NULL; |
| else if (rc < 0) |
| acl = ERR_PTR(rc); |
| else |
| acl = posix_acl_from_xattr(&init_user_ns, value, rc); |
| kfree(value); |
| return acl; |
| } |
| #endif |