ext2: check xattr name_len before acquiring xattr_sem in ext2_xattr_get

In ext2_xattr_get(), the code will acquire xattr_sem first, later checks
the length of xattr name_len > 255. It's unnecessarily time consuming and
also ext2_xattr_set() checks the length before other checks. So move the
check before acquiring xattr_sem to make these two functions consistent.

Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Wang Sheng-Hui 2011-07-22 08:50:13 -05:00 committed by Jan Kara
parent c878c73f8d
commit 03b5bb3429

View File

@ -161,6 +161,10 @@ ext2_xattr_get(struct inode *inode, int name_index, const char *name,
if (name == NULL)
return -EINVAL;
name_len = strlen(name);
if (name_len > 255)
return -ERANGE;
down_read(&EXT2_I(inode)->xattr_sem);
error = -ENODATA;
if (!EXT2_I(inode)->i_file_acl)
@ -181,12 +185,8 @@ bad_block: ext2_error(inode->i_sb, "ext2_xattr_get",
error = -EIO;
goto cleanup;
}
/* find named attribute */
name_len = strlen(name);
error = -ERANGE;
if (name_len > 255)
goto cleanup;
/* find named attribute */
entry = FIRST_ENTRY(bh);
while (!IS_LAST_ENTRY(entry)) {
struct ext2_xattr_entry *next =