Catch unicode decode errors search for kernel ver

  null_idx = input_bytes.find('\x00', start_idx)

  if null_idx < 0:

    return None

  try:

    linux_banner = input_bytes[start_idx:null_idx].decode()

  except UnicodeDecodeError:

    return None

  mo = re.match(LINUX_BANNER_REGEX, linux_banner)

  if mo:

    return mo.group(1)