protected virtual void ReceiveServerHelloMessage(MemoryStream buf)
{
{
ProtocolVersion server_version = TlsUtilities.ReadVersion(buf);
if (server_version.IsDtls)
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
// Check that this matches what the server is Sending in the record layer
if (!server_version.Equals(this.mRecordStream.ReadVersion))
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
ProtocolVersion client_version = Context.ClientVersion;
if (!server_version.IsEqualOrEarlierVersionOf(client_version))
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
this.mRecordStream.SetWriteVersion(server_version);
ContextAdmin.SetServerVersion(server_version);
this.mTlsClient.NotifyServerVersion(server_version);
}
/*
* Read the server random
*/
this.mSecurityParameters.serverRandom = TlsUtilities.ReadFully(32, buf);
this.mSelectedSessionID = TlsUtilities.ReadOpaque8(buf);
if (this.mSelectedSessionID.Length > 32)
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
this.mTlsClient.NotifySessionID(this.mSelectedSessionID);
this.mResumedSession = this.mSelectedSessionID.Length > 0 && this.mTlsSession != null &&
Arrays.AreEqual(this.mSelectedSessionID, this.mTlsSession.SessionID);
/*
* Find out which CipherSuite the server has chosen and check that it was one of the offered
* ones, and is a valid selection for the negotiated version.
*/
int selectedCipherSuite = TlsUtilities.ReadUint16(buf);
if (!Arrays.Contains(this.mOfferedCipherSuites, selectedCipherSuite) ||
selectedCipherSuite == CipherSuite.TLS_NULL_WITH_NULL_NULL ||
CipherSuite.IsScsv(selectedCipherSuite) ||
!TlsUtilities.IsValidCipherSuiteForVersion(selectedCipherSuite, Context.ServerVersion))
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
this.mTlsClient.NotifySelectedCipherSuite(selectedCipherSuite);
/*
* Find out which CompressionMethod the server has chosen and check that it was one of the
* offered ones.
*/
byte selectedCompressionMethod = TlsUtilities.ReadUint8(buf);
if (!Arrays.Contains(this.mOfferedCompressionMethods, selectedCompressionMethod))
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
this.mTlsClient.NotifySelectedCompressionMethod(selectedCompressionMethod);
/*
* RFC3546 2.2 The extended server hello message format MAY be sent in place of the server
* hello message when the client has requested extended functionality via the extended
* client hello message specified in Section 2.1. ... Note that the extended server hello
* message is only sent in response to an extended client hello message. This prevents the
* possibility that the extended server hello message could "break" existing TLS 1.0
* clients.
*/
this.mServerExtensions = ReadExtensions(buf);
/*
* RFC 3546 2.2 Note that the extended server hello message is only sent in response to an
* extended client hello message.
*
* However, see RFC 5746 exception below. We always include the SCSV, so an Extended Server
* Hello is always allowed.
*/
if (this.mServerExtensions != null)
{
foreach (int extType in this.mServerExtensions.Keys)
{
/*
* RFC 5746 3.6. 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 (extType == ExtensionType.renegotiation_info)
{
continue;
}
/*
* RFC 5246 7.4.1.4 An extension type MUST NOT appear in the ServerHello unless the
* same extension type appeared in the corresponding ClientHello. If a client
* receives an extension type in ServerHello that it did not request in the
* associated ClientHello, it MUST abort the handshake with an unsupported_extension
* fatal alert.
*/
if (null == TlsUtilities.GetExtensionData(this.mClientExtensions, extType))
{
throw new TlsFatalAlert(AlertDescription.unsupported_extension);
}
/*
* 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.mResumedSession)
{
// TODO[compat-gnutls] GnuTLS test server Sends server extensions e.g. ec_point_formats
// TODO[compat-openssl] OpenSSL test server Sends server extensions e.g. ec_point_formats
// TODO[compat-polarssl] PolarSSL test server Sends server extensions e.g. ec_point_formats
// throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
}
}
/*
* RFC 5746 3.4. Client Behavior: Initial Handshake
*/
{
/*
* When a ServerHello is received, the client MUST check if it includes the
* "renegotiation_info" extension:
*/
byte[] renegExtData = TlsUtilities.GetExtensionData(this.mServerExtensions, ExtensionType.renegotiation_info);
if (renegExtData != null)
{
/*
* If the extension is present, set the secure_renegotiation flag to TRUE. The
* client MUST then verify that the length of the "renegotiated_connection"
* field is zero, and if it is not, MUST abort the handshake (by Sending a fatal
* handshake_failure alert).
*/
this.mSecureRenegotiation = true;
if (!Arrays.ConstantTimeAreEqual(renegExtData, CreateRenegotiationInfo(TlsUtilities.EmptyBytes)))
{
throw new TlsFatalAlert(AlertDescription.handshake_failure);
}
}
}
// TODO[compat-gnutls] GnuTLS test server fails to Send renegotiation_info extension when resuming
this.mTlsClient.NotifySecureRenegotiation(this.mSecureRenegotiation);
IDictionary sessionClientExtensions = mClientExtensions, sessionServerExtensions = mServerExtensions;
if (this.mResumedSession)
{
if (selectedCipherSuite != this.mSessionParameters.CipherSuite ||
selectedCompressionMethod != this.mSessionParameters.CompressionAlgorithm)
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
sessionClientExtensions = null;
sessionServerExtensions = this.mSessionParameters.ReadServerExtensions();
}
this.mSecurityParameters.cipherSuite = selectedCipherSuite;
this.mSecurityParameters.compressionAlgorithm = selectedCompressionMethod;
if (sessionServerExtensions != null)
{
{
/*
* RFC 7366 3. If a server receives an encrypt-then-MAC request extension from a client
* and then selects a stream or Authenticated Encryption with Associated Data (AEAD)
* ciphersuite, it MUST NOT send an encrypt-then-MAC response extension back to the
* client.
*/
bool serverSentEncryptThenMAC = TlsExtensionsUtilities.HasEncryptThenMacExtension(sessionServerExtensions);
if (serverSentEncryptThenMAC && !TlsUtilities.IsBlockCipherSuite(selectedCipherSuite))
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
this.mSecurityParameters.encryptThenMac = serverSentEncryptThenMAC;
}
this.mSecurityParameters.extendedMasterSecret = TlsExtensionsUtilities.HasExtendedMasterSecretExtension(sessionServerExtensions);
this.mSecurityParameters.maxFragmentLength = ProcessMaxFragmentLengthExtension(sessionClientExtensions,
sessionServerExtensions, AlertDescription.illegal_parameter);
this.mSecurityParameters.truncatedHMac = TlsExtensionsUtilities.HasTruncatedHMacExtension(sessionServerExtensions);
/*
* TODO It's surprising that there's no provision to allow a 'fresh' CertificateStatus to be sent in
* a session resumption handshake.
*/
this.mAllowCertificateStatus = !this.mResumedSession &&
TlsUtilities.HasExpectedEmptyExtensionData(sessionServerExtensions, ExtensionType.status_request,
AlertDescription.illegal_parameter);
this.mExpectSessionTicket = !this.mResumedSession &&
TlsUtilities.HasExpectedEmptyExtensionData(sessionServerExtensions, ExtensionType.session_ticket,
AlertDescription.illegal_parameter);
}
/*
* TODO[session-hash]
*
* draft-ietf-tls-session-hash-04 4. Clients and servers SHOULD NOT accept handshakes
* that do not use the extended master secret [..]. (and see 5.2, 5.3)
*/
if (sessionClientExtensions != null)
{
this.mTlsClient.ProcessServerExtensions(sessionServerExtensions);
}
this.mSecurityParameters.prfAlgorithm = GetPrfAlgorithm(Context, this.mSecurityParameters.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.
*/
this.mSecurityParameters.verifyDataLength = 12;
}
protected virtual IDictionary CheckServerExtensions()
{
return(this.mServerExtensions = TlsExtensionsUtilities.EnsureExtensionsInitialised(this.mServerExtensions));
}
protected virtual void SendClientHelloMessage()
{
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 (!Arrays.Contains(this.mOfferedCipherSuites, mSessionParameters.CipherSuite) ||
!Arrays.Contains(this.mOfferedCompressionMethods, mSessionParameters.CompressionAlgorithm))
{
session_id = TlsUtilities.EmptyBytes;
}
}
this.mClientExtensions = this.mTlsClient.GetClientExtensions();
this.mSecurityParameters.extendedMasterSecret = TlsExtensionsUtilities.HasExtendedMasterSecretExtension(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.mClientExtensions = TlsExtensionsUtilities.EnsureExtensionsInitialised(this.mClientExtensions);
// this.mClientExtensions[ExtensionType.renegotiation_info] = CreateRenegotiationInfo(TlsUtilities.EmptyBytes);
this.mOfferedCipherSuites = Arrays.Append(mOfferedCipherSuites, 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(mOfferedCipherSuites, CipherSuite.TLS_FALLBACK_SCSV))
{
this.mOfferedCipherSuites = Arrays.Append(mOfferedCipherSuites, CipherSuite.TLS_FALLBACK_SCSV);
}
TlsUtilities.WriteUint16ArrayWithUint16Length(mOfferedCipherSuites, message);
}
TlsUtilities.WriteUint8ArrayWithUint8Length(mOfferedCompressionMethods, message);
if (mClientExtensions != null)
{
WriteExtensions(message, mClientExtensions);
}
message.WriteToRecordStream(this);
}
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 ProcessClientHello(ServerHandshakeState state, byte[] body)
{
MemoryStream buf = new MemoryStream(body, false);
// TODO Read RFCs for guidance on the expected record layer version number
ProtocolVersion client_version = TlsUtilities.ReadVersion(buf);
if (!client_version.IsDtls)
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
/*
* Read the client random
*/
byte[] client_random = TlsUtilities.ReadFully(32, buf);
byte[] sessionID = TlsUtilities.ReadOpaque8(buf);
if (sessionID.Length > 32)
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
// TODO RFC 4347 has the cookie length restricted to 32, but not in RFC 6347
byte[] cookie = TlsUtilities.ReadOpaque8(buf);
int cipher_suites_length = TlsUtilities.ReadUint16(buf);
if (cipher_suites_length < 2 || (cipher_suites_length & 1) != 0)
{
throw new TlsFatalAlert(AlertDescription.decode_error);
}
/*
* NOTE: "If the session_id field is not empty (implying a session resumption request) this
* vector must include at least the cipher_suite from that session."
*/
state.offeredCipherSuites = TlsUtilities.ReadUint16Array(cipher_suites_length / 2, buf);
int compression_methods_length = TlsUtilities.ReadUint8(buf);
if (compression_methods_length < 1)
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
state.offeredCompressionMethods = TlsUtilities.ReadUint8Array(compression_methods_length, buf);
/*
* 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.
*/
state.clientExtensions = TlsProtocol.ReadExtensions(buf);
TlsServerContextImpl context = state.serverContext;
SecurityParameters securityParameters = context.SecurityParameters;
/*
* TODO[session-hash]
*
* draft-ietf-tls-session-hash-04 4. Clients and servers SHOULD NOT accept handshakes
* that do not use the extended master secret [..]. (and see 5.2, 5.3)
*/
securityParameters.extendedMasterSecret = TlsExtensionsUtilities.HasExtendedMasterSecretExtension(state.clientExtensions);
context.SetClientVersion(client_version);
state.server.NotifyClientVersion(client_version);
state.server.NotifyFallback(Arrays.Contains(state.offeredCipherSuites, CipherSuite.TLS_FALLBACK_SCSV));
securityParameters.clientRandom = client_random;
state.server.NotifyOfferedCipherSuites(state.offeredCipherSuites);
state.server.NotifyOfferedCompressionMethods(state.offeredCompressionMethods);
/*
* RFC 5746 3.6. Server Behavior: Initial Handshake
*/
{
/*
* 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.
*/
/*
* When a ClientHello is received, the server MUST check if it includes the
* TLS_EMPTY_RENEGOTIATION_INFO_SCSV SCSV. If it does, set the secure_renegotiation flag
* to TRUE.
*/
if (Arrays.Contains(state.offeredCipherSuites, CipherSuite.TLS_EMPTY_RENEGOTIATION_INFO_SCSV))
{
state.secure_renegotiation = true;
}
/*
* The server MUST check if the "renegotiation_info" extension is included in the
* ClientHello.
*/
byte[] renegExtData = TlsUtilities.GetExtensionData(state.clientExtensions, ExtensionType.renegotiation_info);
if (renegExtData != null)
{
/*
* If the extension is present, set secure_renegotiation flag to TRUE. The
* server MUST then verify that the length of the "renegotiated_connection"
* field is zero, and if it is not, MUST abort the handshake.
*/
state.secure_renegotiation = true;
if (!Arrays.ConstantTimeAreEqual(renegExtData, TlsProtocol.CreateRenegotiationInfo(TlsUtilities.EmptyBytes)))
{
throw new TlsFatalAlert(AlertDescription.handshake_failure);
}
}
}
state.server.NotifySecureRenegotiation(state.secure_renegotiation);
if (state.clientExtensions != null)
{
state.server.ProcessClientExtensions(state.clientExtensions);
}
}
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 ReceiveClientHelloMessage(MemoryStream buf)
{
ProtocolVersion client_version = TlsUtilities.ReadVersion(buf);
mRecordStream.SetWriteVersion(client_version);
if (client_version.IsDtls)
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
byte[] client_random = TlsUtilities.ReadFully(32, buf);
/*
* TODO RFC 5077 3.4. If a ticket is presented by the client, the server MUST NOT attempt to
* use the Session ID in the ClientHello for stateful session resumption.
*/
byte[] sessionID = TlsUtilities.ReadOpaque8(buf);
if (sessionID.Length > 32)
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
/*
* TODO RFC 5246 7.4.1.2. If the session_id field is not empty (implying a session
* resumption request), this vector MUST include at least the cipher_suite from that
* session.
*/
int cipher_suites_length = TlsUtilities.ReadUint16(buf);
if (cipher_suites_length < 2 || (cipher_suites_length & 1) != 0)
{
throw new TlsFatalAlert(AlertDescription.decode_error);
}
this.mOfferedCipherSuites = TlsUtilities.ReadUint16Array(cipher_suites_length / 2, buf);
/*
* TODO RFC 5246 7.4.1.2. If the session_id field is not empty (implying a session
* resumption request), it MUST include the compression_method from that session.
*/
int compression_methods_length = TlsUtilities.ReadUint8(buf);
if (compression_methods_length < 1)
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
this.mOfferedCompressionMethods = TlsUtilities.ReadUint8Array(compression_methods_length, buf);
/*
* 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.
*/
this.mClientExtensions = ReadExtensions(buf);
/*
* TODO[resumption] Check RFC 7627 5.4. for required behaviour
*/
/*
* RFC 7627 4. Clients and servers SHOULD NOT accept handshakes that do not use the extended
* master secret [..]. (and see 5.2, 5.3)
*/
this.mSecurityParameters.extendedMasterSecret = TlsExtensionsUtilities.HasExtendedMasterSecretExtension(mClientExtensions);
if (!mSecurityParameters.IsExtendedMasterSecret && mTlsServer.RequiresExtendedMasterSecret())
{
throw new TlsFatalAlert(AlertDescription.handshake_failure);
}
ContextAdmin.SetClientVersion(client_version);
mTlsServer.NotifyClientVersion(client_version);
mTlsServer.NotifyFallback(Arrays.Contains(mOfferedCipherSuites, CipherSuite.TLS_FALLBACK_SCSV));
mSecurityParameters.clientRandom = client_random;
mTlsServer.NotifyOfferedCipherSuites(mOfferedCipherSuites);
mTlsServer.NotifyOfferedCompressionMethods(mOfferedCompressionMethods);
/*
* RFC 5746 3.6. Server Behavior: Initial Handshake
*/
{
/*
* 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.
*/
/*
* When a ClientHello is received, the server MUST check if it includes the
* TLS_EMPTY_RENEGOTIATION_INFO_SCSV SCSV. If it does, set the secure_renegotiation flag
* to TRUE.
*/
if (Arrays.Contains(mOfferedCipherSuites, CipherSuite.TLS_EMPTY_RENEGOTIATION_INFO_SCSV))
{
this.mSecureRenegotiation = true;
}
/*
* The server MUST check if the "renegotiation_info" extension is included in the
* ClientHello.
*/
byte[] renegExtData = TlsUtilities.GetExtensionData(mClientExtensions, ExtensionType.renegotiation_info);
if (renegExtData != null)
{
/*
* If the extension is present, set secure_renegotiation flag to TRUE. The
* server MUST then verify that the length of the "renegotiated_connection"
* field is zero, and if it is not, MUST abort the handshake.
*/
this.mSecureRenegotiation = true;
if (!Arrays.ConstantTimeAreEqual(renegExtData, CreateRenegotiationInfo(TlsUtilities.EmptyBytes)))
{
throw new TlsFatalAlert(AlertDescription.handshake_failure);
}
}
}
mTlsServer.NotifySecureRenegotiation(this.mSecureRenegotiation);
if (mClientExtensions != null)
{
// NOTE: Validates the padding extension data, if present
TlsExtensionsUtilities.GetPaddingExtension(mClientExtensions);
mTlsServer.ProcessClientExtensions(mClientExtensions);
}
}
protected virtual void ReceiveServerHelloMessage(MemoryStream buf)
{
ProtocolVersion writeVersion = TlsUtilities.ReadVersion(buf);
if (writeVersion.IsDtls)
{
throw new TlsFatalAlert(0x2f);
}
if (!writeVersion.Equals(base.mRecordStream.ReadVersion))
{
throw new TlsFatalAlert(0x2f);
}
ProtocolVersion clientVersion = this.Context.ClientVersion;
if (!writeVersion.IsEqualOrEarlierVersionOf(clientVersion))
{
throw new TlsFatalAlert(0x2f);
}
base.mRecordStream.SetWriteVersion(writeVersion);
this.ContextAdmin.SetServerVersion(writeVersion);
this.mTlsClient.NotifyServerVersion(writeVersion);
base.mSecurityParameters.serverRandom = TlsUtilities.ReadFully(0x20, buf);
this.mSelectedSessionID = TlsUtilities.ReadOpaque8(buf);
if (this.mSelectedSessionID.Length > 0x20)
{
throw new TlsFatalAlert(0x2f);
}
this.mTlsClient.NotifySessionID(this.mSelectedSessionID);
base.mResumedSession = ((this.mSelectedSessionID.Length > 0) && (base.mTlsSession != null)) && Arrays.AreEqual(this.mSelectedSessionID, base.mTlsSession.SessionID);
int n = TlsUtilities.ReadUint16(buf);
if ((!Arrays.Contains(base.mOfferedCipherSuites, n) || (n == 0)) || (CipherSuite.IsScsv(n) || !TlsUtilities.IsValidCipherSuiteForVersion(n, this.Context.ServerVersion)))
{
throw new TlsFatalAlert(0x2f);
}
this.mTlsClient.NotifySelectedCipherSuite(n);
byte num2 = TlsUtilities.ReadUint8(buf);
if (!Arrays.Contains(base.mOfferedCompressionMethods, num2))
{
throw new TlsFatalAlert(0x2f);
}
this.mTlsClient.NotifySelectedCompressionMethod(num2);
base.mServerExtensions = TlsProtocol.ReadExtensions(buf);
if (base.mServerExtensions != null)
{
IEnumerator enumerator = base.mServerExtensions.Keys.GetEnumerator();
try
{
while (enumerator.MoveNext())
{
int current = (int)enumerator.Current;
if (current != 0xff01)
{
if (TlsUtilities.GetExtensionData(base.mClientExtensions, current) == null)
{
throw new TlsFatalAlert(110);
}
if (base.mResumedSession)
{
}
}
}
}
finally
{
if (enumerator is IDisposable disposable)
{
IDisposable disposable;
disposable.Dispose();
}
}
}
byte[] extensionData = TlsUtilities.GetExtensionData(base.mServerExtensions, 0xff01);
if (extensionData != null)
{
base.mSecureRenegotiation = true;
if (!Arrays.ConstantTimeAreEqual(extensionData, TlsProtocol.CreateRenegotiationInfo(TlsUtilities.EmptyBytes)))
{
throw new TlsFatalAlert(40);
}
}
this.mTlsClient.NotifySecureRenegotiation(base.mSecureRenegotiation);
IDictionary mClientExtensions = base.mClientExtensions;
IDictionary mServerExtensions = base.mServerExtensions;
if (base.mResumedSession)
{
if ((n != base.mSessionParameters.CipherSuite) || (num2 != base.mSessionParameters.CompressionAlgorithm))
{
throw new TlsFatalAlert(0x2f);
}
mClientExtensions = null;
mServerExtensions = base.mSessionParameters.ReadServerExtensions();
}
base.mSecurityParameters.cipherSuite = n;
base.mSecurityParameters.compressionAlgorithm = num2;
if (mServerExtensions != null)
{
bool flag = TlsExtensionsUtilities.HasEncryptThenMacExtension(mServerExtensions);
if (flag && !TlsUtilities.IsBlockCipherSuite(n))
{
throw new TlsFatalAlert(0x2f);
}
base.mSecurityParameters.encryptThenMac = flag;
base.mSecurityParameters.extendedMasterSecret = TlsExtensionsUtilities.HasExtendedMasterSecretExtension(mServerExtensions);
base.mSecurityParameters.maxFragmentLength = this.ProcessMaxFragmentLengthExtension(mClientExtensions, mServerExtensions, 0x2f);
base.mSecurityParameters.truncatedHMac = TlsExtensionsUtilities.HasTruncatedHMacExtension(mServerExtensions);
base.mAllowCertificateStatus = !base.mResumedSession && TlsUtilities.HasExpectedEmptyExtensionData(mServerExtensions, 5, 0x2f);
base.mExpectSessionTicket = !base.mResumedSession && TlsUtilities.HasExpectedEmptyExtensionData(mServerExtensions, 0x23, 0x2f);
}
if (mClientExtensions != null)
{
this.mTlsClient.ProcessServerExtensions(mServerExtensions);
}
base.mSecurityParameters.prfAlgorithm = TlsProtocol.GetPrfAlgorithm(this.Context, base.mSecurityParameters.CipherSuite);
base.mSecurityParameters.verifyDataLength = 12;
}
protected static short EvaluateMaxFragmentLengthExtension(bool resumedSession, IDictionary clientExtensions, IDictionary serverExtensions, byte alertDescription)
{
short maxFragmentLengthExtension = TlsExtensionsUtilities.GetMaxFragmentLengthExtension(serverExtensions);
if (maxFragmentLengthExtension >= 0 && (!MaxFragmentLength.IsValid((byte)maxFragmentLengthExtension) || (!resumedSession && maxFragmentLengthExtension != TlsExtensionsUtilities.GetMaxFragmentLengthExtension(clientExtensions))))
{
throw new TlsFatalAlert(alertDescription);
}
return(maxFragmentLengthExtension);
}
protected virtual void ReceiveServerHelloMessage(MemoryStream buf)
{
ProtocolVersion protocolVersion = TlsUtilities.ReadVersion(buf);
if (protocolVersion.IsDtls)
{
throw new TlsFatalAlert(47);
}
if (!protocolVersion.Equals(this.mRecordStream.ReadVersion))
{
throw new TlsFatalAlert(47);
}
ProtocolVersion clientVersion = this.Context.ClientVersion;
if (!protocolVersion.IsEqualOrEarlierVersionOf(clientVersion))
{
throw new TlsFatalAlert(47);
}
this.mRecordStream.SetWriteVersion(protocolVersion);
this.ContextAdmin.SetServerVersion(protocolVersion);
this.mTlsClient.NotifyServerVersion(protocolVersion);
this.mSecurityParameters.serverRandom = TlsUtilities.ReadFully(32, buf);
this.mSelectedSessionID = TlsUtilities.ReadOpaque8(buf);
if (this.mSelectedSessionID.Length > 32)
{
throw new TlsFatalAlert(47);
}
this.mTlsClient.NotifySessionID(this.mSelectedSessionID);
this.mResumedSession = (this.mSelectedSessionID.Length > 0 && this.mTlsSession != null && Arrays.AreEqual(this.mSelectedSessionID, this.mTlsSession.SessionID));
int num = TlsUtilities.ReadUint16(buf);
if (!Arrays.Contains(this.mOfferedCipherSuites, num) || num == 0 || CipherSuite.IsScsv(num) || !TlsUtilities.IsValidCipherSuiteForVersion(num, this.Context.ServerVersion))
{
throw new TlsFatalAlert(47);
}
this.mTlsClient.NotifySelectedCipherSuite(num);
byte b = TlsUtilities.ReadUint8(buf);
if (!Arrays.Contains(this.mOfferedCompressionMethods, b))
{
throw new TlsFatalAlert(47);
}
this.mTlsClient.NotifySelectedCompressionMethod(b);
this.mServerExtensions = TlsProtocol.ReadExtensions(buf);
if (this.mServerExtensions != null)
{
foreach (int num2 in this.mServerExtensions.Keys)
{
if (num2 != 65281)
{
if (TlsUtilities.GetExtensionData(this.mClientExtensions, num2) == null)
{
throw new TlsFatalAlert(110);
}
bool arg_1B5_0 = this.mResumedSession;
}
}
}
byte[] extensionData = TlsUtilities.GetExtensionData(this.mServerExtensions, 65281);
if (extensionData != null)
{
this.mSecureRenegotiation = true;
if (!Arrays.ConstantTimeAreEqual(extensionData, TlsProtocol.CreateRenegotiationInfo(TlsUtilities.EmptyBytes)))
{
throw new TlsFatalAlert(40);
}
}
this.mTlsClient.NotifySecureRenegotiation(this.mSecureRenegotiation);
IDictionary dictionary = this.mClientExtensions;
IDictionary dictionary2 = this.mServerExtensions;
if (this.mResumedSession)
{
if (num != this.mSessionParameters.CipherSuite || b != this.mSessionParameters.CompressionAlgorithm)
{
throw new TlsFatalAlert(47);
}
dictionary = null;
dictionary2 = this.mSessionParameters.ReadServerExtensions();
}
this.mSecurityParameters.cipherSuite = num;
this.mSecurityParameters.compressionAlgorithm = b;
if (dictionary2 != null)
{
bool flag = TlsExtensionsUtilities.HasEncryptThenMacExtension(dictionary2);
if (flag && !TlsUtilities.IsBlockCipherSuite(num))
{
throw new TlsFatalAlert(47);
}
this.mSecurityParameters.encryptThenMac = flag;
this.mSecurityParameters.extendedMasterSecret = TlsExtensionsUtilities.HasExtendedMasterSecretExtension(dictionary2);
this.mSecurityParameters.maxFragmentLength = this.ProcessMaxFragmentLengthExtension(dictionary, dictionary2, 47);
this.mSecurityParameters.truncatedHMac = TlsExtensionsUtilities.HasTruncatedHMacExtension(dictionary2);
this.mAllowCertificateStatus = (!this.mResumedSession && TlsUtilities.HasExpectedEmptyExtensionData(dictionary2, 5, 47));
this.mExpectSessionTicket = (!this.mResumedSession && TlsUtilities.HasExpectedEmptyExtensionData(dictionary2, 35, 47));
}
if (dictionary != null)
{
this.mTlsClient.ProcessServerExtensions(dictionary2);
}
this.mSecurityParameters.prfAlgorithm = TlsProtocol.GetPrfAlgorithm(this.Context, this.mSecurityParameters.CipherSuite);
this.mSecurityParameters.verifyDataLength = 12;
}