Ejemplo n.º 1
0
        public bool IsValid(SecureChannelHandshakeHello hello, byte[] masterKey)
        {
            using (MemoryStream mS = new MemoryStream(32))
            {
                hello.WriteTo(mS);
                mS.Position = 0;

                BinaryNumber computedHmac = new BinaryNumber((new HMACSHA256(masterKey)).ComputeHash(mS));
                return(_hmac.Equals(computedHmac));
            }
        }
Ejemplo n.º 2
0
        public SecureChannelHandshakeAuthentication(SecureChannelHandshakeHello hello, byte[] masterKey)
            : base(SecureChannelCode.None)
        {
            using (MemoryStream mS = new MemoryStream(32))
            {
                hello.WriteTo(mS);
                mS.Position = 0;

                _hmac = new BinaryNumber((new HMACSHA256(masterKey)).ComputeHash(mS));
            }
        }
Ejemplo n.º 3
0
        protected byte[] GenerateMasterKey(SecureChannelHandshakeHello clientHello, SecureChannelHandshakeHello serverHello, byte[] preSharedKey, KeyAgreement keyAgreement, byte[] otherPartyPublicKey)
        {
            using (MemoryStream mS = new MemoryStream(128))
            {
                clientHello.WriteTo(mS);
                serverHello.WriteTo(mS);

                if (preSharedKey == null)
                {
                    keyAgreement.HmacMessage = mS.ToArray();
                }
                else
                {
                    keyAgreement.HmacMessage = (new HMACSHA256(preSharedKey)).ComputeHash(mS.ToArray());
                }
            }

            return(keyAgreement.DeriveKeyMaterial(otherPartyPublicKey));
        }
Ejemplo n.º 4
0
        private void ProtocolV4(Stream stream)
        {
            WriteBufferedStream bufferedStream = new WriteBufferedStream(stream, 8 * 1024);

            #region 1. hello handshake

            //read client hello
            SecureChannelHandshakeHello clientHello = new SecureChannelHandshakeHello(bufferedStream);

            //select crypto option
            _selectedCryptoOption = _supportedOptions & clientHello.CryptoOptions;

            if (_selectedCryptoOption == SecureChannelCryptoOptionFlags.None)
            {
                throw new SecureChannelException(SecureChannelCode.NoMatchingCryptoAvailable, _remotePeerEP, _remotePeerCert);
            }
            else if ((_selectedCryptoOption & SecureChannelCryptoOptionFlags.ECDHE256_RSA_WITH_AES256_CBC_HMAC_SHA256) > 0)
            {
                _selectedCryptoOption = SecureChannelCryptoOptionFlags.ECDHE256_RSA_WITH_AES256_CBC_HMAC_SHA256;
            }
            else if ((_selectedCryptoOption & SecureChannelCryptoOptionFlags.DHE2048_RSA_WITH_AES256_CBC_HMAC_SHA256) > 0)
            {
                _selectedCryptoOption = SecureChannelCryptoOptionFlags.DHE2048_RSA_WITH_AES256_CBC_HMAC_SHA256;
            }
            else
            {
                throw new SecureChannelException(SecureChannelCode.NoMatchingCryptoAvailable, _remotePeerEP, _remotePeerCert);
            }

            //send server hello
            SecureChannelHandshakeHello serverHello = new SecureChannelHandshakeHello(BinaryNumber.GenerateRandomNumber256(), _selectedCryptoOption);
            serverHello.WriteTo(bufferedStream);

            #endregion

            #region 2. key exchange

            SymmetricEncryptionAlgorithm encAlgo;
            string       hashAlgo;
            KeyAgreement keyAgreement;

            switch (_selectedCryptoOption)
            {
            case SecureChannelCryptoOptionFlags.DHE2048_RSA_WITH_AES256_CBC_HMAC_SHA256:
                encAlgo      = SymmetricEncryptionAlgorithm.Rijndael;
                hashAlgo     = "SHA256";
                keyAgreement = new DiffieHellman(DiffieHellmanGroupType.RFC3526, 2048, KeyAgreementKeyDerivationFunction.Hmac, KeyAgreementKeyDerivationHashAlgorithm.SHA256);
                break;

            case SecureChannelCryptoOptionFlags.ECDHE256_RSA_WITH_AES256_CBC_HMAC_SHA256:
                encAlgo      = SymmetricEncryptionAlgorithm.Rijndael;
                hashAlgo     = "SHA256";
                keyAgreement = new TechnitiumLibrary.Security.Cryptography.ECDiffieHellman(256, KeyAgreementKeyDerivationFunction.Hmac, KeyAgreementKeyDerivationHashAlgorithm.SHA256);
                break;

            default:
                throw new SecureChannelException(SecureChannelCode.NoMatchingCryptoAvailable, _remotePeerEP, _remotePeerCert);
            }

            //send server key exchange data
            new SecureChannelHandshakeKeyExchange(keyAgreement.GetPublicKey(), _serverCredentials.PrivateKey, hashAlgo).WriteTo(bufferedStream);
            bufferedStream.Flush();

            //read client key exchange data
            SecureChannelHandshakeKeyExchange clientKeyExchange = new SecureChannelHandshakeKeyExchange(bufferedStream);

            //generate master key
            byte[] masterKey = GenerateMasterKey(clientHello, serverHello, _preSharedKey, keyAgreement, clientKeyExchange.PublicKey);

            //verify master key using HMAC authentication
            {
                SecureChannelHandshakeAuthentication clientAuthentication = new SecureChannelHandshakeAuthentication(bufferedStream);
                if (!clientAuthentication.IsValid(serverHello, masterKey))
                {
                    throw new SecureChannelException(SecureChannelCode.ProtocolAuthenticationFailed, _remotePeerEP, _remotePeerCert);
                }

                SecureChannelHandshakeAuthentication serverAuthentication = new SecureChannelHandshakeAuthentication(clientHello, masterKey);
                serverAuthentication.WriteTo(bufferedStream);
                bufferedStream.Flush();
            }

            //enable channel encryption
            switch (encAlgo)
            {
            case SymmetricEncryptionAlgorithm.Rijndael:
                //using MD5 for generating AES IV of 128bit block size
                HashAlgorithm md5Hash = HashAlgorithm.Create("MD5");
                byte[]        eIV     = md5Hash.ComputeHash(serverHello.Nonce.Number);
                byte[]        dIV     = md5Hash.ComputeHash(clientHello.Nonce.Number);

                //create encryption and decryption objects
                SymmetricCryptoKey encryptionKey = new SymmetricCryptoKey(SymmetricEncryptionAlgorithm.Rijndael, masterKey, eIV, PaddingMode.None);
                SymmetricCryptoKey decryptionKey = new SymmetricCryptoKey(SymmetricEncryptionAlgorithm.Rijndael, masterKey, dIV, PaddingMode.None);

                //enable encryption
                EnableEncryption(stream, encryptionKey, decryptionKey, new HMACSHA256(masterKey), new HMACSHA256(masterKey));
                break;

            default:
                throw new SecureChannelException(SecureChannelCode.NoMatchingCryptoAvailable, _remotePeerEP, _remotePeerCert);
            }

            //channel encryption is ON!

            #endregion

            #region 3. exchange & verify certificates & signatures

            if (!IsReNegotiating())
            {
                //read client certificate
                _remotePeerCert = new SecureChannelHandshakeCertificate(this).Certificate;

                //verify client certificate
                try
                {
                    _remotePeerCert.Verify(_trustedRootCertificates);
                }
                catch (Exception ex)
                {
                    throw new SecureChannelException(SecureChannelCode.InvalidRemoteCertificate, _remotePeerEP, _remotePeerCert, "Invalid remote certificate.", ex);
                }
            }

            //verify key exchange signature
            switch (_selectedCryptoOption)
            {
            case SecureChannelCryptoOptionFlags.DHE2048_RSA_WITH_AES256_CBC_HMAC_SHA256:
            case SecureChannelCryptoOptionFlags.ECDHE256_RSA_WITH_AES256_CBC_HMAC_SHA256:
                if (_remotePeerCert.PublicKeyEncryptionAlgorithm != AsymmetricEncryptionAlgorithm.RSA)
                {
                    throw new SecureChannelException(SecureChannelCode.InvalidRemoteCertificateAlgorithm, _remotePeerEP, _remotePeerCert);
                }

                if (!clientKeyExchange.IsSignatureValid(_remotePeerCert, "SHA256"))
                {
                    throw new SecureChannelException(SecureChannelCode.InvalidRemoteKeyExchangeSignature, _remotePeerEP, _remotePeerCert);
                }

                break;

            default:
                throw new SecureChannelException(SecureChannelCode.NoMatchingCryptoAvailable, _remotePeerEP, _remotePeerCert);
            }

            if ((_manager != null) && !_manager.ProceedConnection(_remotePeerCert))
            {
                throw new SecureChannelException(SecureChannelCode.SecurityManagerDeclinedAccess, _remotePeerEP, _remotePeerCert, "Security manager declined access.");
            }

            //send server certificate
            if (!IsReNegotiating())
            {
                new SecureChannelHandshakeCertificate(_serverCredentials.Certificate).WriteTo(this);
                this.Flush();
            }

            #endregion
        }