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ext2: introduce helper for xattr entry validation 

Introduce helper function ext2_xattr_entry_valid()
for xattr entry validation and clean up the entry
check related code.

Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Chengguang Xu <cgxu519@zoho.com.cn>
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Chengguang Xu 2019-05-14 06:40:42 +08:00 committed by Jan Kara
parent 02475de9bb
commit f4c3fb8c43
1 changed files with 21 additions and 11 deletions
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32
fs/ext2/xattr.c
View File

@ -144,6 +144,22 @@ ext2_xattr_header_valid(struct ext2_xattr_header *header)
return true;
}
static bool
ext2_xattr_entry_valid(struct ext2_xattr_entry *entry, size_t end_offs)
{
size_t size;
if (entry->e_value_block != 0)
return false;
size = le32_to_cpu(entry->e_value_size);
if (size > end_offs ||
le16_to_cpu(entry->e_value_offs) + size > end_offs)
return false;
return true;
}
/*
* ext2_xattr_get()
*
@ -213,14 +229,10 @@ bad_block:
error = -ENODATA;
goto cleanup;
found:
/* check the buffer size */
if (entry->e_value_block != 0)
goto bad_block;
size = le32_to_cpu(entry->e_value_size);
if (size > inode->i_sb->s_blocksize ||
le16_to_cpu(entry->e_value_offs) + size > inode->i_sb->s_blocksize)
if (!ext2_xattr_entry_valid(entry, inode->i_sb->s_blocksize))
goto bad_block;
size = le32_to_cpu(entry->e_value_size);
if (ext2_xattr_cache_insert(ea_block_cache, bh))
ea_idebug(inode, "cache insert failed");
if (buffer) {
@ -481,12 +493,10 @@ bad_block:
if (flags & XATTR_CREATE)
goto cleanup;
if (!here->e_value_block && here->e_value_size) {
size_t size = le32_to_cpu(here->e_value_size);
if (le16_to_cpu(here->e_value_offs) + size >
sb->s_blocksize || size > sb->s_blocksize)
if (!ext2_xattr_entry_valid(here, sb->s_blocksize))
goto bad_block;
free += EXT2_XATTR_SIZE(size);
free += EXT2_XATTR_SIZE(
le32_to_cpu(here->e_value_size));
}
free += EXT2_XATTR_LEN(name_len);
}