/**
* Encode this {@link ServerSRPParams} to an {@link OutputStream}.
*
* @param output
* the {@link OutputStream} to encode to.
* @throws IOException
*/
public virtual void Encode(Stream output)
{
TlsSrpUtilities.WriteSrpParameter(m_N, output);
TlsSrpUtilities.WriteSrpParameter(m_g, output);
TlsUtilities.WriteOpaque8(m_s, output);
TlsSrpUtilities.WriteSrpParameter(m_B, output);
}
public static void WriteExplicitECParameters(byte[] ecPointFormats, ECDomainParameters ecParameters,
Stream output)
{
ECCurve curve = ecParameters.Curve;
if (ECAlgorithms.IsFpCurve(curve))
{
TlsUtilities.WriteUint8(ECCurveType.explicit_prime, output);
WriteECParameter(curve.Field.Characteristic, output);
}
else if (ECAlgorithms.IsF2mCurve(curve))
{
IPolynomialExtensionField field = (IPolynomialExtensionField)curve.Field;
int[] exponents = field.MinimalPolynomial.GetExponentsPresent();
TlsUtilities.WriteUint8(ECCurveType.explicit_char2, output);
int m = exponents[exponents.Length - 1];
TlsUtilities.CheckUint16(m);
TlsUtilities.WriteUint16(m, output);
if (exponents.Length == 3)
{
TlsUtilities.WriteUint8(ECBasisType.ec_basis_trinomial, output);
WriteECExponent(exponents[1], output);
}
else if (exponents.Length == 5)
{
TlsUtilities.WriteUint8(ECBasisType.ec_basis_pentanomial, output);
WriteECExponent(exponents[1], output);
WriteECExponent(exponents[2], output);
WriteECExponent(exponents[3], output);
}
else
{
throw new ArgumentException("Only trinomial and pentomial curves are supported");
}
}
else
{
throw new ArgumentException("'ecParameters' not a known curve type");
}
WriteECFieldElement(curve.A, output);
WriteECFieldElement(curve.B, output);
TlsUtilities.WriteOpaque8(SerializeECPoint(ecPointFormats, ecParameters.G), output);
WriteECParameter(ecParameters.N, output);
WriteECParameter(ecParameters.H, output);
}
public static byte[] CreateUseSrtpExtension(UseSrtpData useSrtpData)
{
if (useSrtpData == null)
{
throw new ArgumentNullException("useSrtpData");
}
MemoryStream buf = new MemoryStream();
// SRTPProtectionProfiles
TlsUtilities.WriteUint16ArrayWithUint16Length(useSrtpData.ProtectionProfiles, buf);
// srtp_mki
TlsUtilities.WriteOpaque8(useSrtpData.Mki, buf);
return(buf.ToArray());
}
public static void WriteExplicitECParameters(byte[] ecPointFormats, ECDomainParameters ecParameters, Stream output)
{
ECCurve curve = ecParameters.Curve;
if (ECAlgorithms.IsFpCurve(curve))
{
TlsUtilities.WriteUint8(1, output);
WriteECParameter(curve.Field.Characteristic, output);
}
else
{
if (!ECAlgorithms.IsF2mCurve(curve))
{
throw new ArgumentException("'ecParameters' not a known curve type");
}
IPolynomialExtensionField polynomialExtensionField = (IPolynomialExtensionField)curve.Field;
int[] exponentsPresent = polynomialExtensionField.MinimalPolynomial.GetExponentsPresent();
TlsUtilities.WriteUint8(2, output);
int i = exponentsPresent[exponentsPresent.Length - 1];
TlsUtilities.CheckUint16(i);
TlsUtilities.WriteUint16(i, output);
if (exponentsPresent.Length == 3)
{
TlsUtilities.WriteUint8(1, output);
WriteECExponent(exponentsPresent[1], output);
}
else
{
if (exponentsPresent.Length != 5)
{
throw new ArgumentException("Only trinomial and pentomial curves are supported");
}
TlsUtilities.WriteUint8(2, output);
WriteECExponent(exponentsPresent[1], output);
WriteECExponent(exponentsPresent[2], output);
WriteECExponent(exponentsPresent[3], output);
}
}
WriteECFieldElement(curve.A, output);
WriteECFieldElement(curve.B, output);
TlsUtilities.WriteOpaque8(SerializeECPoint(ecPointFormats, ecParameters.G), output);
WriteECParameter(ecParameters.N, output);
WriteECParameter(ecParameters.H, output);
}
public static byte[] CreateALPNExtension(System.Collections.Generic.List <string> protocols)
{
if (protocols == null)
{
throw new TlsFatalAlert(AlertDescription.internal_error);
}
// https://tools.ietf.org/html/rfc7301
using (var buf = new BestHTTP.Extensions.BufferPoolMemoryStream())
{
using (var protoBuf = new BestHTTP.Extensions.BufferPoolMemoryStream())
{
foreach (string protocol in protocols)
{
// Empty strings MUST NOT be included and byte strings MUST NOT be truncated.
if (string.IsNullOrEmpty(protocol))
{
continue;
}
byte[] asciiEncoding = Strings.ToAsciiByteArray(protocol);
if (asciiEncoding.Length < 1)
{
throw new TlsFatalAlert(AlertDescription.internal_error);
}
TlsUtilities.WriteOpaque8(asciiEncoding, protoBuf);
BestHTTP.PlatformSupport.Memory.BufferPool.Release(asciiEncoding);
}
TlsUtilities.CheckUint16(protoBuf.Length);
TlsUtilities.WriteUint16((int)protoBuf.Length, buf);
protoBuf.WriteTo(buf);
}
return(buf.ToArray());
}
}
protected virtual byte[] GenerateClientHello(ClientHandshakeState state, TlsClient client)
{
ProtocolVersion client_version = client.ClientVersion;
if (!client_version.IsDtls)
{
throw new TlsFatalAlert(AlertDescription.internal_error);
}
TlsClientContextImpl context = state.clientContext;
context.SetClientVersion(client_version);
SecurityParameters securityParameters = context.SecurityParameters;
// Session ID
byte[] session_id = TlsUtilities.EmptyBytes;
if (state.tlsSession != null)
{
session_id = state.tlsSession.SessionID;
if (session_id == null || session_id.Length > 32)
{
session_id = TlsUtilities.EmptyBytes;
}
}
bool fallback = client.IsFallback;
state.offeredCipherSuites = client.GetCipherSuites();
if (session_id.Length > 0 && state.sessionParameters != null)
{
if (!state.sessionParameters.IsExtendedMasterSecret ||
!Arrays.Contains(state.offeredCipherSuites, state.sessionParameters.CipherSuite) ||
CompressionMethod.cls_null != state.sessionParameters.CompressionAlgorithm)
{
session_id = TlsUtilities.EmptyBytes;
}
}
state.clientExtensions = TlsExtensionsUtilities.EnsureExtensionsInitialised(client.GetClientExtensions());
TlsExtensionsUtilities.AddExtendedMasterSecretExtension(state.clientExtensions);
MemoryStream buf = new MemoryStream();
TlsUtilities.WriteVersion(client_version, buf);
buf.Write(securityParameters.ClientRandom, 0, securityParameters.ClientRandom.Length);
TlsUtilities.WriteOpaque8(session_id, buf);
// Cookie
TlsUtilities.WriteOpaque8(TlsUtilities.EmptyBytes, buf);
// Cipher Suites (and SCSV)
{
/*
* RFC 5746 3.4. The client MUST include either an empty "renegotiation_info" extension,
* or the TLS_EMPTY_RENEGOTIATION_INFO_SCSV signaling cipher suite value in the
* ClientHello. Including both is NOT RECOMMENDED.
*/
byte[] renegExtData = TlsUtilities.GetExtensionData(state.clientExtensions, ExtensionType.renegotiation_info);
bool noRenegExt = (null == renegExtData);
bool noRenegSCSV = !Arrays.Contains(state.offeredCipherSuites, CipherSuite.TLS_EMPTY_RENEGOTIATION_INFO_SCSV);
if (noRenegExt && noRenegSCSV)
{
// TODO Consider whether to default to a client extension instead
state.offeredCipherSuites = Arrays.Append(state.offeredCipherSuites, CipherSuite.TLS_EMPTY_RENEGOTIATION_INFO_SCSV);
}
/*
* RFC 7507 4. If a client sends a ClientHello.client_version containing a lower value
* than the latest (highest-valued) version supported by the client, it SHOULD include
* the TLS_FALLBACK_SCSV cipher suite value in ClientHello.cipher_suites [..]. (The
* client SHOULD put TLS_FALLBACK_SCSV after all cipher suites that it actually intends
* to negotiate.)
*/
if (fallback && !Arrays.Contains(state.offeredCipherSuites, CipherSuite.TLS_FALLBACK_SCSV))
{
state.offeredCipherSuites = Arrays.Append(state.offeredCipherSuites, CipherSuite.TLS_FALLBACK_SCSV);
}
TlsUtilities.WriteUint16ArrayWithUint16Length(state.offeredCipherSuites, buf);
}
TlsUtilities.WriteUint8ArrayWithUint8Length(new byte[] { CompressionMethod.cls_null }, buf);
TlsProtocol.WriteExtensions(buf, state.clientExtensions);
return(buf.ToArray());
}
public static void WriteECPoint(byte[] ecPointFormats, ECPoint point, Stream output)
{
TlsUtilities.WriteOpaque8(SerializeECPoint(ecPointFormats, point), output);
}
public static void WriteECParameter(BigInteger x, Stream output)
{
TlsUtilities.WriteOpaque8(BigIntegers.AsUnsignedByteArray(x), output);
}
public static void WriteECFieldElement(int fieldSize, BigInteger x, Stream output)
{
TlsUtilities.WriteOpaque8(SerializeECFieldElement(fieldSize, x), output);
}
public static void WriteECFieldElement(ECFieldElement x, Stream output)
{
TlsUtilities.WriteOpaque8(x.GetEncoded(), output);
}
protected virtual byte[] GenerateServerHello(ServerHandshakeState state)
{
SecurityParameters securityParameters = state.serverContext.SecurityParameters;
MemoryStream buf = new MemoryStream();
{
ProtocolVersion server_version = state.server.GetServerVersion();
if (!server_version.IsEqualOrEarlierVersionOf(state.serverContext.ClientVersion))
{
throw new TlsFatalAlert(AlertDescription.internal_error);
}
// TODO Read RFCs for guidance on the expected record layer version number
// recordStream.setReadVersion(server_version);
// recordStream.setWriteVersion(server_version);
// recordStream.setRestrictReadVersion(true);
state.serverContext.SetServerVersion(server_version);
TlsUtilities.WriteVersion(state.serverContext.ServerVersion, buf);
}
buf.Write(securityParameters.ServerRandom, 0, securityParameters.ServerRandom.Length);
/*
* The server may return an empty session_id to indicate that the session will not be cached
* and therefore cannot be resumed.
*/
TlsUtilities.WriteOpaque8(TlsUtilities.EmptyBytes, buf);
int selectedCipherSuite = state.server.GetSelectedCipherSuite();
if (!Arrays.Contains(state.offeredCipherSuites, selectedCipherSuite) ||
selectedCipherSuite == CipherSuite.TLS_NULL_WITH_NULL_NULL ||
CipherSuite.IsScsv(selectedCipherSuite) ||
!TlsUtilities.IsValidCipherSuiteForVersion(selectedCipherSuite, state.serverContext.ServerVersion))
{
throw new TlsFatalAlert(AlertDescription.internal_error);
}
ValidateSelectedCipherSuite(selectedCipherSuite, AlertDescription.internal_error);
securityParameters.cipherSuite = selectedCipherSuite;
byte selectedCompressionMethod = state.server.GetSelectedCompressionMethod();
if (!Arrays.Contains(state.offeredCompressionMethods, selectedCompressionMethod))
{
throw new TlsFatalAlert(AlertDescription.internal_error);
}
securityParameters.compressionAlgorithm = selectedCompressionMethod;
TlsUtilities.WriteUint16(selectedCipherSuite, buf);
TlsUtilities.WriteUint8(selectedCompressionMethod, buf);
state.serverExtensions = state.server.GetServerExtensions();
/*
* RFC 5746 3.6. Server Behavior: Initial Handshake
*/
if (state.secure_renegotiation)
{
byte[] renegExtData = TlsUtilities.GetExtensionData(state.serverExtensions, ExtensionType.renegotiation_info);
bool noRenegExt = (null == renegExtData);
if (noRenegExt)
{
/*
* Note that sending a "renegotiation_info" extension in response to a ClientHello
* containing only the SCSV is an explicit exception to the prohibition in RFC 5246,
* Section 7.4.1.4, on the server sending unsolicited extensions and is only allowed
* because the client is signaling its willingness to receive the extension via the
* TLS_EMPTY_RENEGOTIATION_INFO_SCSV SCSV.
*/
/*
* If the secure_renegotiation flag is set to TRUE, the server MUST include an empty
* "renegotiation_info" extension in the ServerHello message.
*/
state.serverExtensions = TlsExtensionsUtilities.EnsureExtensionsInitialised(state.serverExtensions);
state.serverExtensions[ExtensionType.renegotiation_info] = TlsProtocol.CreateRenegotiationInfo(TlsUtilities.EmptyBytes);
}
}
if (securityParameters.extendedMasterSecret)
{
state.serverExtensions = TlsExtensionsUtilities.EnsureExtensionsInitialised(state.serverExtensions);
TlsExtensionsUtilities.AddExtendedMasterSecretExtension(state.serverExtensions);
}
/*
* TODO RFC 3546 2.3 If [...] the older session is resumed, then the server MUST ignore
* extensions appearing in the client hello, and send a server hello containing no
* extensions.
*/
if (state.serverExtensions != null)
{
securityParameters.encryptThenMac = TlsExtensionsUtilities.HasEncryptThenMacExtension(state.serverExtensions);
securityParameters.maxFragmentLength = EvaluateMaxFragmentLengthExtension(state.resumedSession,
state.clientExtensions, state.serverExtensions, AlertDescription.internal_error);
securityParameters.truncatedHMac = TlsExtensionsUtilities.HasTruncatedHMacExtension(state.serverExtensions);
/*
* TODO It's surprising that there's no provision to allow a 'fresh' CertificateStatus to be sent in
* a session resumption handshake.
*/
state.allowCertificateStatus = !state.resumedSession &&
TlsUtilities.HasExpectedEmptyExtensionData(state.serverExtensions, ExtensionType.status_request,
AlertDescription.internal_error);
state.expectSessionTicket = !state.resumedSession &&
TlsUtilities.HasExpectedEmptyExtensionData(state.serverExtensions, ExtensionType.session_ticket,
AlertDescription.internal_error);
TlsProtocol.WriteExtensions(buf, state.serverExtensions);
}
securityParameters.prfAlgorithm = TlsProtocol.GetPrfAlgorithm(state.serverContext,
securityParameters.CipherSuite);
/*
* RFC 5264 7.4.9. Any cipher suite which does not explicitly specify verify_data_length
* has a verify_data_length equal to 12. This includes all existing cipher suites.
*/
securityParameters.verifyDataLength = 12;
return(buf.ToArray());
}
protected virtual void SendServerHelloMessage()
{
HandshakeMessage handshakeMessage = new HandshakeMessage(2);
ProtocolVersion serverVersion = mTlsServer.GetServerVersion();
if (!serverVersion.IsEqualOrEarlierVersionOf(Context.ClientVersion))
{
throw new TlsFatalAlert(80);
}
mRecordStream.ReadVersion = serverVersion;
mRecordStream.SetWriteVersion(serverVersion);
mRecordStream.SetRestrictReadVersion(enabled: true);
ContextAdmin.SetServerVersion(serverVersion);
TlsUtilities.WriteVersion(serverVersion, handshakeMessage);
handshakeMessage.Write(mSecurityParameters.serverRandom);
TlsUtilities.WriteOpaque8(TlsUtilities.EmptyBytes, handshakeMessage);
int selectedCipherSuite = mTlsServer.GetSelectedCipherSuite();
if (!Arrays.Contains(mOfferedCipherSuites, selectedCipherSuite) || selectedCipherSuite == 0 || CipherSuite.IsScsv(selectedCipherSuite) || !TlsUtilities.IsValidCipherSuiteForVersion(selectedCipherSuite, Context.ServerVersion))
{
throw new TlsFatalAlert(80);
}
mSecurityParameters.cipherSuite = selectedCipherSuite;
byte selectedCompressionMethod = mTlsServer.GetSelectedCompressionMethod();
if (!Arrays.Contains(mOfferedCompressionMethods, selectedCompressionMethod))
{
throw new TlsFatalAlert(80);
}
mSecurityParameters.compressionAlgorithm = selectedCompressionMethod;
TlsUtilities.WriteUint16(selectedCipherSuite, handshakeMessage);
TlsUtilities.WriteUint8(selectedCompressionMethod, handshakeMessage);
mServerExtensions = mTlsServer.GetServerExtensions();
if (mSecureRenegotiation)
{
byte[] extensionData = TlsUtilities.GetExtensionData(mServerExtensions, 65281);
if (null == extensionData)
{
mServerExtensions = TlsExtensionsUtilities.EnsureExtensionsInitialised(mServerExtensions);
mServerExtensions[65281] = TlsProtocol.CreateRenegotiationInfo(TlsUtilities.EmptyBytes);
}
}
if (mSecurityParameters.extendedMasterSecret)
{
mServerExtensions = TlsExtensionsUtilities.EnsureExtensionsInitialised(mServerExtensions);
TlsExtensionsUtilities.AddExtendedMasterSecretExtension(mServerExtensions);
}
if (mServerExtensions != null)
{
mSecurityParameters.encryptThenMac = TlsExtensionsUtilities.HasEncryptThenMacExtension(mServerExtensions);
mSecurityParameters.maxFragmentLength = ProcessMaxFragmentLengthExtension(mClientExtensions, mServerExtensions, 80);
mSecurityParameters.truncatedHMac = TlsExtensionsUtilities.HasTruncatedHMacExtension(mServerExtensions);
mAllowCertificateStatus = (!mResumedSession && TlsUtilities.HasExpectedEmptyExtensionData(mServerExtensions, 5, 80));
mExpectSessionTicket = (!mResumedSession && TlsUtilities.HasExpectedEmptyExtensionData(mServerExtensions, 35, 80));
TlsProtocol.WriteExtensions(handshakeMessage, mServerExtensions);
}
mSecurityParameters.prfAlgorithm = TlsProtocol.GetPrfAlgorithm(Context, mSecurityParameters.CipherSuite);
mSecurityParameters.verifyDataLength = 12;
ApplyMaxFragmentLengthExtension();
handshakeMessage.WriteToRecordStream(this);
}
protected virtual void SendServerHelloMessage()
{
HandshakeMessage message = new HandshakeMessage(HandshakeType.server_hello);
{
ProtocolVersion server_version = mTlsServer.GetServerVersion();
if (!server_version.IsEqualOrEarlierVersionOf(Context.ClientVersion))
{
throw new TlsFatalAlert(AlertDescription.internal_error);
}
mRecordStream.ReadVersion = server_version;
mRecordStream.SetWriteVersion(server_version);
mRecordStream.SetRestrictReadVersion(true);
ContextAdmin.SetServerVersion(server_version);
TlsUtilities.WriteVersion(server_version, message);
}
message.Write(this.mSecurityParameters.serverRandom);
/*
* The server may return an empty session_id to indicate that the session will not be cached
* and therefore cannot be resumed.
*/
TlsUtilities.WriteOpaque8(TlsUtilities.EmptyBytes, message);
int selectedCipherSuite = mTlsServer.GetSelectedCipherSuite();
if (!Arrays.Contains(mOfferedCipherSuites, selectedCipherSuite) ||
selectedCipherSuite == CipherSuite.TLS_NULL_WITH_NULL_NULL ||
CipherSuite.IsScsv(selectedCipherSuite) ||
!TlsUtilities.IsValidCipherSuiteForVersion(selectedCipherSuite, Context.ServerVersion))
{
throw new TlsFatalAlert(AlertDescription.internal_error);
}
mSecurityParameters.cipherSuite = selectedCipherSuite;
byte selectedCompressionMethod = mTlsServer.GetSelectedCompressionMethod();
if (!Arrays.Contains(mOfferedCompressionMethods, selectedCompressionMethod))
{
throw new TlsFatalAlert(AlertDescription.internal_error);
}
mSecurityParameters.compressionAlgorithm = selectedCompressionMethod;
TlsUtilities.WriteUint16(selectedCipherSuite, message);
TlsUtilities.WriteUint8(selectedCompressionMethod, message);
this.mServerExtensions = TlsExtensionsUtilities.EnsureExtensionsInitialised(mTlsServer.GetServerExtensions());
/*
* RFC 5746 3.6. Server Behavior: Initial Handshake
*/
if (this.mSecureRenegotiation)
{
byte[] renegExtData = TlsUtilities.GetExtensionData(this.mServerExtensions, ExtensionType.renegotiation_info);
bool noRenegExt = (null == renegExtData);
if (noRenegExt)
{
/*
* Note that Sending a "renegotiation_info" extension in response to a ClientHello
* containing only the SCSV is an explicit exception to the prohibition in RFC 5246,
* Section 7.4.1.4, on the server Sending unsolicited extensions and is only allowed
* because the client is signaling its willingness to receive the extension via the
* TLS_EMPTY_RENEGOTIATION_INFO_SCSV SCSV.
*/
/*
* If the secure_renegotiation flag is set to TRUE, the server MUST include an empty
* "renegotiation_info" extension in the ServerHello message.
*/
this.mServerExtensions[ExtensionType.renegotiation_info] = CreateRenegotiationInfo(TlsUtilities.EmptyBytes);
}
}
if (TlsUtilities.IsSsl(mTlsServerContext))
{
mSecurityParameters.extendedMasterSecret = false;
}
else if (mSecurityParameters.IsExtendedMasterSecret)
{
TlsExtensionsUtilities.AddExtendedMasterSecretExtension(mServerExtensions);
}
/*
* TODO RFC 3546 2.3 If [...] the older session is resumed, then the server MUST ignore
* extensions appearing in the client hello, and Send a server hello containing no
* extensions.
*/
if (this.mServerExtensions.Count > 0)
{
this.mSecurityParameters.encryptThenMac = TlsExtensionsUtilities.HasEncryptThenMacExtension(mServerExtensions);
this.mSecurityParameters.maxFragmentLength = ProcessMaxFragmentLengthExtension(mClientExtensions,
mServerExtensions, AlertDescription.internal_error);
this.mSecurityParameters.truncatedHMac = TlsExtensionsUtilities.HasTruncatedHMacExtension(mServerExtensions);
/*
* TODO It's surprising that there's no provision to allow a 'fresh' CertificateStatus to be sent in
* a session resumption handshake.
*/
this.mAllowCertificateStatus = !mResumedSession &&
TlsUtilities.HasExpectedEmptyExtensionData(mServerExtensions, ExtensionType.status_request,
AlertDescription.internal_error);
this.mExpectSessionTicket = !mResumedSession &&
TlsUtilities.HasExpectedEmptyExtensionData(mServerExtensions, ExtensionType.session_ticket,
AlertDescription.internal_error);
WriteExtensions(message, this.mServerExtensions);
}
mSecurityParameters.prfAlgorithm = GetPrfAlgorithm(Context, mSecurityParameters.CipherSuite);
/*
* RFC 5246 7.4.9. Any cipher suite which does not explicitly specify verify_data_length has
* a verify_data_length equal to 12. This includes all existing cipher suites.
*/
mSecurityParameters.verifyDataLength = 12;
ApplyMaxFragmentLengthExtension();
message.WriteToRecordStream(this);
}
protected virtual void SendClientHelloMessage()
{
if (HTTPManager.Logger.Level <= Loglevels.All)
{
HTTPManager.Logger.Verbose("TlsClientProtocol", "SendClientHelloMessage", this.LoggingContext);
}
this.mRecordStream.SetWriteVersion(this.mTlsClient.ClientHelloRecordLayerVersion);
ProtocolVersion client_version = this.mTlsClient.ClientVersion;
if (client_version.IsDtls)
{
throw new TlsFatalAlert(AlertDescription.internal_error);
}
ContextAdmin.SetClientVersion(client_version);
/*
* TODO RFC 5077 3.4. When presenting a ticket, the client MAY generate and include a
* Session ID in the TLS ClientHello.
*/
byte[] session_id = TlsUtilities.EmptyBytes;
if (this.mTlsSession != null)
{
session_id = this.mTlsSession.SessionID;
if (session_id == null || session_id.Length > 32)
{
session_id = TlsUtilities.EmptyBytes;
}
}
bool fallback = this.mTlsClient.IsFallback;
this.mOfferedCipherSuites = this.mTlsClient.GetCipherSuites();
this.mOfferedCompressionMethods = this.mTlsClient.GetCompressionMethods();
if (session_id.Length > 0 && this.mSessionParameters != null)
{
if (!mSessionParameters.IsExtendedMasterSecret ||
!Arrays.Contains(this.mOfferedCipherSuites, mSessionParameters.CipherSuite) ||
!Arrays.Contains(this.mOfferedCompressionMethods, mSessionParameters.CompressionAlgorithm))
{
session_id = TlsUtilities.EmptyBytes;
}
}
this.mClientExtensions = TlsExtensionsUtilities.EnsureExtensionsInitialised(this.mTlsClient.GetClientExtensions());
if (!client_version.IsSsl)
{
TlsExtensionsUtilities.AddExtendedMasterSecretExtension(this.mClientExtensions);
}
HandshakeMessage message = new HandshakeMessage(HandshakeType.client_hello);
TlsUtilities.WriteVersion(client_version, message);
message.Write(this.mSecurityParameters.ClientRandom);
TlsUtilities.WriteOpaque8(session_id, message);
// Cipher Suites (and SCSV)
{
/*
* RFC 5746 3.4. The client MUST include either an empty "renegotiation_info" extension,
* or the TLS_EMPTY_RENEGOTIATION_INFO_SCSV signaling cipher suite value in the
* ClientHello. Including both is NOT RECOMMENDED.
*/
byte[] renegExtData = TlsUtilities.GetExtensionData(mClientExtensions, ExtensionType.renegotiation_info);
bool noRenegExt = (null == renegExtData);
bool noRenegScsv = !Arrays.Contains(mOfferedCipherSuites, CipherSuite.TLS_EMPTY_RENEGOTIATION_INFO_SCSV);
if (noRenegExt && noRenegScsv)
{
// TODO Consider whether to default to a client extension instead
this.mOfferedCipherSuites = Arrays.Append(mOfferedCipherSuites, CipherSuite.TLS_EMPTY_RENEGOTIATION_INFO_SCSV);
}
/*
* RFC 7507 4. If a client sends a ClientHello.client_version containing a lower value
* than the latest (highest-valued) version supported by the client, it SHOULD include
* the TLS_FALLBACK_SCSV cipher suite value in ClientHello.cipher_suites [..]. (The
* client SHOULD put TLS_FALLBACK_SCSV after all cipher suites that it actually intends
* to negotiate.)
*/
if (fallback && !Arrays.Contains(mOfferedCipherSuites, CipherSuite.TLS_FALLBACK_SCSV))
{
this.mOfferedCipherSuites = Arrays.Append(mOfferedCipherSuites, CipherSuite.TLS_FALLBACK_SCSV);
}
TlsUtilities.WriteUint16ArrayWithUint16Length(mOfferedCipherSuites, message);
}
TlsUtilities.WriteUint8ArrayWithUint8Length(mOfferedCompressionMethods, message);
WriteExtensions(message, mClientExtensions);
message.WriteToRecordStream(this);
}
protected virtual byte[] GenerateClientHello(ClientHandshakeState state, TlsClient client)
{
MemoryStream buf = new MemoryStream();
ProtocolVersion client_version = client.ClientVersion;
if (!client_version.IsDtls)
{
throw new TlsFatalAlert(AlertDescription.internal_error);
}
TlsClientContextImpl context = state.clientContext;
context.SetClientVersion(client_version);
TlsUtilities.WriteVersion(client_version, buf);
SecurityParameters securityParameters = context.SecurityParameters;
buf.Write(securityParameters.ClientRandom, 0, securityParameters.ClientRandom.Length);
// Session ID
byte[] session_id = TlsUtilities.EmptyBytes;
if (state.tlsSession != null)
{
session_id = state.tlsSession.SessionID;
if (session_id == null || session_id.Length > 32)
{
session_id = TlsUtilities.EmptyBytes;
}
}
TlsUtilities.WriteOpaque8(session_id, buf);
// Cookie
TlsUtilities.WriteOpaque8(TlsUtilities.EmptyBytes, buf);
bool fallback = client.IsFallback;
/*
* Cipher suites
*/
state.offeredCipherSuites = client.GetCipherSuites();
// Integer -> byte[]
state.clientExtensions = client.GetClientExtensions();
// Cipher Suites (and SCSV)
{
/*
* RFC 5746 3.4. The client MUST include either an empty "renegotiation_info" extension,
* or the TLS_EMPTY_RENEGOTIATION_INFO_SCSV signaling cipher suite value in the
* ClientHello. Including both is NOT RECOMMENDED.
*/
byte[] renegExtData = TlsUtilities.GetExtensionData(state.clientExtensions, ExtensionType.renegotiation_info);
bool noRenegExt = (null == renegExtData);
bool noRenegSCSV = !Arrays.Contains(state.offeredCipherSuites, CipherSuite.TLS_EMPTY_RENEGOTIATION_INFO_SCSV);
if (noRenegExt && noRenegSCSV)
{
// TODO Consider whether to default to a client extension instead
state.offeredCipherSuites = Arrays.Append(state.offeredCipherSuites, CipherSuite.TLS_EMPTY_RENEGOTIATION_INFO_SCSV);
}
/*
* draft-ietf-tls-downgrade-scsv-00 4. If a client sends a ClientHello.client_version
* containing a lower value than the latest (highest-valued) version supported by the
* client, it SHOULD include the TLS_FALLBACK_SCSV cipher suite value in
* ClientHello.cipher_suites.
*/
if (fallback && !Arrays.Contains(state.offeredCipherSuites, CipherSuite.TLS_FALLBACK_SCSV))
{
state.offeredCipherSuites = Arrays.Append(state.offeredCipherSuites, CipherSuite.TLS_FALLBACK_SCSV);
}
TlsUtilities.WriteUint16ArrayWithUint16Length(state.offeredCipherSuites, buf);
}
// TODO Add support for compression
// Compression methods
// state.offeredCompressionMethods = client.getCompressionMethods();
state.offeredCompressionMethods = new byte[] { CompressionMethod.cls_null };
TlsUtilities.WriteUint8ArrayWithUint8Length(state.offeredCompressionMethods, buf);
// Extensions
if (state.clientExtensions != null)
{
TlsProtocol.WriteExtensions(buf, state.clientExtensions);
}
return(buf.ToArray());
}