ext2: reject inodes with negative size

Don't load an inode with a negative size; this causes integer overflow
problems in the VFS.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/ext2/inode.c

@@ -1476,6 +1476,10 @@ struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
 		inode->i_size |= ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
 	else
 		ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
+	if (i_size_read(inode) < 0) {
+		ret = -EFSCORRUPTED;
+		goto bad_inode;
+	}
 	ei->i_dtime = 0;
 	inode->i_generation = le32_to_cpu(raw_inode->i_generation);
 	ei->i_state = 0;