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Assets/BestHTTP/SecureProtocol/crypto/tls/AbstractTlsKeyExchange.cs

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+#if !BESTHTTP_DISABLE_ALTERNATE_SSL && (!UNITY_WEBGL || UNITY_EDITOR)
+
+using System;
+using System.Collections;
+using System.IO;
+
+namespace Org.BouncyCastle.Crypto.Tls
+{
+    public abstract class AbstractTlsKeyExchange
+        :   TlsKeyExchange
+    {
+        protected readonly int mKeyExchange;
+        protected IList mSupportedSignatureAlgorithms;
+
+        protected TlsContext mContext;
+
+        protected AbstractTlsKeyExchange(int keyExchange, IList supportedSignatureAlgorithms)
+        {
+            this.mKeyExchange = keyExchange;
+            this.mSupportedSignatureAlgorithms = supportedSignatureAlgorithms;
+        }
+
+        protected virtual DigitallySigned ParseSignature(Stream input)
+        {
+            DigitallySigned signature = DigitallySigned.Parse(mContext, input);
+            SignatureAndHashAlgorithm signatureAlgorithm = signature.Algorithm;
+            if (signatureAlgorithm != null)
+            {
+                TlsUtilities.VerifySupportedSignatureAlgorithm(mSupportedSignatureAlgorithms, signatureAlgorithm);
+            }
+            return signature;
+        }
+
+        public virtual void Init(TlsContext context)
+        {
+            this.mContext = context;
+
+            ProtocolVersion clientVersion = context.ClientVersion;
+
+            if (TlsUtilities.IsSignatureAlgorithmsExtensionAllowed(clientVersion))
+            {
+                /*
+                 * RFC 5264 7.4.1.4.1. If the client does not send the signature_algorithms extension,
+                 * the server MUST do the following:
+                 * 
+                 * - If the negotiated key exchange algorithm is one of (RSA, DHE_RSA, DH_RSA, RSA_PSK,
+                 * ECDH_RSA, ECDHE_RSA), behave as if client had sent the value {sha1,rsa}.
+                 * 
+                 * - If the negotiated key exchange algorithm is one of (DHE_DSS, DH_DSS), behave as if
+                 * the client had sent the value {sha1,dsa}.
+                 * 
+                 * - If the negotiated key exchange algorithm is one of (ECDH_ECDSA, ECDHE_ECDSA),
+                 * behave as if the client had sent value {sha1,ecdsa}.
+                 */
+                if (this.mSupportedSignatureAlgorithms == null)
+                {
+                    switch (mKeyExchange)
+                    {
+                    case KeyExchangeAlgorithm.DH_DSS:
+                    case KeyExchangeAlgorithm.DHE_DSS:
+                    case KeyExchangeAlgorithm.SRP_DSS:
+                    {
+                        this.mSupportedSignatureAlgorithms = TlsUtilities.GetDefaultDssSignatureAlgorithms();
+                        break;
+                    }
+
+                    case KeyExchangeAlgorithm.ECDH_ECDSA:
+                    case KeyExchangeAlgorithm.ECDHE_ECDSA:
+                    {
+                        this.mSupportedSignatureAlgorithms = TlsUtilities.GetDefaultECDsaSignatureAlgorithms();
+                        break;
+                    }
+
+                    case KeyExchangeAlgorithm.DH_RSA:
+                    case KeyExchangeAlgorithm.DHE_RSA:
+                    case KeyExchangeAlgorithm.ECDH_RSA:
+                    case KeyExchangeAlgorithm.ECDHE_RSA:
+                    case KeyExchangeAlgorithm.RSA:
+                    case KeyExchangeAlgorithm.RSA_PSK:
+                    case KeyExchangeAlgorithm.SRP_RSA:
+                    {
+                        this.mSupportedSignatureAlgorithms = TlsUtilities.GetDefaultRsaSignatureAlgorithms();
+                        break;
+                    }
+
+                    case KeyExchangeAlgorithm.DHE_PSK:
+                    case KeyExchangeAlgorithm.ECDHE_PSK:
+                    case KeyExchangeAlgorithm.PSK:
+                    case KeyExchangeAlgorithm.SRP:
+                        break;
+
+                    default:
+                        throw new InvalidOperationException("unsupported key exchange algorithm");
+                    }
+                }
+
+            }
+            else if (this.mSupportedSignatureAlgorithms != null)
+            {
+                throw new InvalidOperationException("supported_signature_algorithms not allowed for " + clientVersion);
+            }
+        }
+
+        public abstract void SkipServerCredentials();
+
+        public virtual void ProcessServerCertificate(Certificate serverCertificate)
+        {
+            if (mSupportedSignatureAlgorithms == null)
+            {
+                /*
+                 * TODO RFC 2264 7.4.2. Unless otherwise specified, the signing algorithm for the
+                 * certificate must be the same as the algorithm for the certificate key.
+                 */
+            }
+            else
+            {
+                /*
+                 * TODO RFC 5264 7.4.2. If the client provided a "signature_algorithms" extension, then
+                 * all certificates provided by the server MUST be signed by a hash/signature algorithm
+                 * pair that appears in that extension.
+                 */
+            }
+        }
+
+        public virtual void ProcessServerCredentials(TlsCredentials serverCredentials)
+        {
+            ProcessServerCertificate(serverCredentials.Certificate);
+        }
+
+        public virtual bool RequiresServerKeyExchange
+        {
+            get { return false; }
+        }
+
+        public virtual byte[] GenerateServerKeyExchange()
+        {
+            if (RequiresServerKeyExchange)
+                throw new TlsFatalAlert(AlertDescription.internal_error);
+
+            return null;
+        }
+
+        public virtual void SkipServerKeyExchange()
+        {
+            if (RequiresServerKeyExchange)
+                throw new TlsFatalAlert(AlertDescription.unexpected_message);
+        }
+
+        public virtual void ProcessServerKeyExchange(Stream input)
+        {
+            if (!RequiresServerKeyExchange)
+            {
+                throw new TlsFatalAlert(AlertDescription.unexpected_message);
+            }
+        }
+
+        public abstract void ValidateCertificateRequest(CertificateRequest certificateRequest);
+
+        public virtual void SkipClientCredentials()
+        {
+        }
+
+        public abstract void ProcessClientCredentials(TlsCredentials clientCredentials);
+
+        public virtual void ProcessClientCertificate(Certificate clientCertificate)
+        {
+        }
+
+        public abstract void GenerateClientKeyExchange(Stream output);
+
+        public virtual void ProcessClientKeyExchange(Stream input)
+        {
+            // Key exchange implementation MUST support client key exchange
+            throw new TlsFatalAlert(AlertDescription.internal_error);
+        }
+
+        public abstract byte[] GeneratePremasterSecret();
+    }
+}
+
+#endif