    def verify_cert_against_key(self, filename, key_filename):
        """
        check that a certificate validates against its private key.
        """
        cert = self.data + filename
        key = self.data + key_filename
        cmd = ("openssl x509 -noout -modulus -in %s | openssl md5" %
               pipes.quote(cert))
        cert_md5 = Popen(cmd, shell=True, stdout=PIPE, stderr=STDOUT).stdout.read()
        cmd = ("openssl rsa -noout -modulus -in %s | openssl md5" %
               pipes.quote(key))
        key_md5 = Popen(cmd, shell=True, stdout=PIPE, stderr=STDOUT).stdout.read()
        if cert_md5 == key_md5:
            return True
        return False
The product receives input or data, but it does
        not validate or incorrectly validates that the input has the
        properties that are required to process the data safely and
        correctly.