protected SslHandshakeStatus ProcessServerHello(HandshakeMessage message)
{
if (m_State != HandshakeType.ClientHello && m_State != HandshakeType.HelloRequest)
{
throw new SslException(AlertDescription.UnexpectedMessage, "ServerHello message must be preceded by a ClientHello message.");
}
UpdateHashes(message, HashUpdate.All); // input message
if (message.fragment.Length < 2 || message.fragment[0] != GetVersion().major || message.fragment[1] != GetVersion().minor)
{
throw new SslException(AlertDescription.IllegalParameter, "Unknown protocol version of the client.");
}
try {
// extract the time from the client [== 1 uint]
m_ServerTime = new byte[4];
Array.Copy(message.fragment, 2, m_ServerTime, 0, 4);
// extract the random bytes [== 28 bytes]
m_ServerRandom = new byte[28];
Array.Copy(message.fragment, 6, m_ServerRandom, 0, 28);
// extact the session ID [== 0..32 bytes]
int length = message.fragment[34];
if (length > 32)
{
throw new SslException(AlertDescription.IllegalParameter, "The length of the SessionID cannot be more than 32 bytes.");
}
m_SessionID = new byte[length];
Array.Copy(message.fragment, 35, m_SessionID, 0, length);
// extract the selected cipher suite
m_EncryptionScheme = CipherSuites.GetCipherAlgorithmType(message.fragment, 35 + length);
// extract the selected compression method
m_CompressionMethod = CompressionAlgorithm.GetCompressionAlgorithmType(message.fragment, 37 + length);
} catch (Exception e) {
throw new SslException(e, AlertDescription.InternalError, "The message is invalid.");
}
return(new SslHandshakeStatus(SslStatus.MessageIncomplete, null));
}
protected override byte[] GetClientHello()
{
if (m_State != HandshakeType.Nothing && m_State != HandshakeType.Finished)
{
throw new SslException(AlertDescription.UnexpectedMessage, "ClientHello message must be the first message or must be preceded by a Finished message.");
}
m_IsNegotiating = true;
m_State = HandshakeType.ClientHello;
byte[] ciphers = CipherSuites.GetCipherAlgorithmBytes(m_Options.AllowedAlgorithms);
byte[] compr = CompressionAlgorithm.GetCompressionAlgorithmBytes(m_Options.AllowedAlgorithms);
HandshakeMessage temp = new HandshakeMessage(HandshakeType.ClientHello, new byte[38 + ciphers.Length + compr.Length]);
m_ClientTime = GetUnixTime();
m_ClientRandom = new byte[28];
m_RNG.GetBytes(m_ClientRandom);
ProtocolVersion pv = CompatibilityLayer.GetMaxProtocol(m_Options.Protocol);
temp.fragment[0] = pv.major;
temp.fragment[1] = pv.minor;
Array.Copy(m_ClientTime, 0, temp.fragment, 2, 4);
Array.Copy(m_ClientRandom, 0, temp.fragment, 6, 28);
temp.fragment[34] = 0; // do not resume a session, and do not let the other side cache it
temp.fragment[35] = (byte)(ciphers.Length / 256);
temp.fragment[36] = (byte)(ciphers.Length % 256);
Array.Copy(ciphers, 0, temp.fragment, 37, ciphers.Length);
temp.fragment[37 + ciphers.Length] = (byte)compr.Length;
Array.Copy(compr, 0, temp.fragment, 38 + ciphers.Length, compr.Length);
byte[] ret = temp.ToBytes();
UpdateHashes(ret, HashUpdate.All); // client hello message
return(m_RecordLayer.EncryptBytes(ret, 0, ret.Length, ContentType.Handshake));
}
protected SslHandshakeStatus ProcessServerHello(HandshakeMessage message)
{
if (m_State != HandshakeType.ClientHello && m_State != HandshakeType.HelloRequest)
{
throw new SslException(AlertDescription.UnexpectedMessage, "ServerHello message must be preceded by a ClientHello message.");
}
UpdateHashes(message, HashUpdate.All); // input message
//Violation with tls spec. If remote side uses higher protocol version than your, then we must answer with your highest version
//if (message.fragment.Length < 2 || message.fragment[0] != GetVersion().major || message.fragment[1] != GetVersion().minor)
//throw new SslException(AlertDescription.IllegalParameter, "Unknown protocol version of the client.");
int currentProcessedLen = 2;
try {
// extract the time from the client [== 1 uint]
m_ServerTime = new byte[4];
Buffer.BlockCopy(message.fragment, currentProcessedLen, m_ServerTime, 0, 4);
currentProcessedLen += 4;
// extract the random bytes [== 28 bytes]
m_ServerRandom = new byte[28];
Buffer.BlockCopy(message.fragment, currentProcessedLen, m_ServerRandom, 0, 28);
currentProcessedLen += 28;
// extact the session ID [== 0..32 bytes]
int length = message.fragment[currentProcessedLen++];
if (length > 32)
{
throw new SslException(AlertDescription.IllegalParameter, "The length of the SessionID cannot be more than 32 bytes.");
}
m_SessionID = new byte[length];
Buffer.BlockCopy(message.fragment, currentProcessedLen, m_SessionID, 0, length);
currentProcessedLen += length;
// extract the selected cipher suite
m_EncryptionScheme = CipherSuites.GetCipherAlgorithmType(message.fragment, currentProcessedLen);
currentProcessedLen += 2;
// extract the selected compression method
m_CompressionMethod = CompressionAlgorithm.GetCompressionAlgorithmType(message.fragment, currentProcessedLen++);
}
catch (Exception e)
{
throw new SslException(e, AlertDescription.InternalError, "The message is invalid.");
}
if (message.fragment.Length == currentProcessedLen)
{
return(new SslHandshakeStatus(SslStatus.MessageIncomplete, null));
}
this.ProcessExtensions(message.fragment, ref currentProcessedLen, ConnectionEnd.Client);
return(new SslHandshakeStatus(SslStatus.MessageIncomplete, null));
}
protected SslHandshakeStatus ProcessClientHello(HandshakeMessage message)
{
if (m_State != HandshakeType.Nothing && m_State != HandshakeType.Finished)
{
throw new SslException(AlertDescription.UnexpectedMessage, "ClientHello message must be the first message or must be preceded by a Finished message.");
}
m_IsNegotiating = true;
UpdateHashes(message, HashUpdate.All); // input message
// process ClientHello
ProtocolVersion pv = new ProtocolVersion(message.fragment[0], message.fragment[1]);
m_MaxClientVersion = pv;
if (CompatibilityLayer.SupportsProtocol(m_Options.Protocol, pv) && pv.GetVersionInt() != GetVersion().GetVersionInt())
{
throw new SslException(AlertDescription.IllegalParameter, "Unknown protocol version of the client.");
}
try {
// extract the time from the client [== 1 uint]
m_ClientTime = new byte[4];
Array.Copy(message.fragment, 2, m_ClientTime, 0, 4);
// extract the random bytes [== 28 bytes]
m_ClientRandom = new byte[28];
Array.Copy(message.fragment, 6, m_ClientRandom, 0, 28);
// extact the session ID [== 0..32 bytes]
int length = message.fragment[34];
if (length > 32)
{
throw new SslException(AlertDescription.IllegalParameter, "The length of the SessionID cannot be more than 32 bytes.");
}
m_SessionID = new byte[length];
Array.Copy(message.fragment, 35, m_SessionID, 0, length);
// extract the available cipher suites
length += 35;
int ciphers_size = message.fragment[length] * 256 + message.fragment[length + 1];
if (ciphers_size < 2 || ciphers_size % 2 != 0)
{
throw new SslException(AlertDescription.IllegalParameter, "The number of ciphers is invalid -or- the cipher length is not even.");
}
byte[] ciphers = new byte[ciphers_size];
Array.Copy(message.fragment, length + 2, ciphers, 0, ciphers_size);
m_EncryptionScheme = CipherSuites.GetCipherSuiteAlgorithm(ciphers, m_Options.AllowedAlgorithms);
// extract the available compression algorithms
length += ciphers_size + 2;
int compressors_size = message.fragment[length];
if (compressors_size == 0)
{
throw new SslException(AlertDescription.IllegalParameter, "No compressor specified.");
}
byte[] compressors = new byte[compressors_size];
Array.Copy(message.fragment, length + 1, compressors, 0, compressors_size);
m_CompressionMethod = CompressionAlgorithm.GetCompressionAlgorithm(compressors, m_Options.AllowedAlgorithms);
} catch (Exception e) {
throw new SslException(e, AlertDescription.InternalError, "The message is invalid.");
}
// create reply
return(GetClientHelloResult());
}
protected void GenerateCiphers(byte[] premaster)
{
byte[] clientrnd = new byte[32], serverrnd = new byte[32];
byte[] random = new byte[64];
Array.Copy(m_ClientTime, 0, clientrnd, 0, 4);
Array.Copy(m_ClientRandom, 0, clientrnd, 4, 28);
Array.Copy(m_ServerTime, 0, serverrnd, 0, 4);
Array.Copy(m_ServerRandom, 0, serverrnd, 4, 28);
m_MasterSecret = GenerateMasterSecret(premaster, clientrnd, serverrnd);
m_CipherSuite = CipherSuites.GetCipherSuite(GetProtocol(), m_MasterSecret, clientrnd, serverrnd, m_EncryptionScheme, m_Options.Entity);
Array.Clear(premaster, 0, premaster.Length);
}
protected SslHandshakeStatus ProcessServerKeyExchange(HandshakeMessage message)
{
if (m_State != HandshakeType.Certificate)
{
throw new SslException(AlertDescription.UnexpectedMessage, "ServerKeyExchange message must be preceded by a Certificate message.");
}
CipherDefinition cd = CipherSuites.GetCipherDefinition(m_EncryptionScheme);
if (!cd.Exportable)
{
throw new SslException(AlertDescription.HandshakeFailure, "The ServerKeyExchange message should not be sent for non-exportable ciphers.");
}
if (m_RemoteCertificate.GetPublicKeyLength() <= 512)
{
throw new SslException(AlertDescription.HandshakeFailure, "The ServerKeyExchange message should not be sent because the server certificate public key is of exportable length.");
}
UpdateHashes(message, HashUpdate.All); // input message
// extract modulus and exponent
RSAParameters pars = new RSAParameters();
int size = message.fragment[0] * 256 + message.fragment[1];
pars.Modulus = new byte[size];
Buffer.BlockCopy(message.fragment, 2, pars.Modulus, 0, size);
int offset = size + 2;
size = message.fragment[offset] * 256 + message.fragment[offset + 1];
pars.Exponent = new byte[size];
Buffer.BlockCopy(message.fragment, offset + 2, pars.Exponent, 0, size);
offset += size + 2;
pars.Modulus = RemoveLeadingZeros(pars.Modulus);
pars.Exponent = RemoveLeadingZeros(pars.Exponent);
m_KeyCipher = new RSACryptoServiceProvider();
m_KeyCipher.ImportParameters(pars);
// compute verification hashes
MD5SHA1CryptoServiceProvider ms = new MD5SHA1CryptoServiceProvider();
ms.TransformBlock(m_ClientTime, 0, m_ClientTime.Length, m_ClientTime, 0);
ms.TransformBlock(m_ClientRandom, 0, m_ClientRandom.Length, m_ClientRandom, 0);
ms.TransformBlock(m_ServerTime, 0, m_ServerTime.Length, m_ServerTime, 0);
ms.TransformBlock(m_ServerRandom, 0, m_ServerRandom.Length, m_ServerRandom, 0);
ms.TransformFinalBlock(message.fragment, 0, offset);
// verify the signature
size = message.fragment[offset] * 256 + message.fragment[offset + 1];
byte[] signature = new byte[size]; // holds the signature returned by the server
Buffer.BlockCopy(message.fragment, offset + 2, signature, 0, size);
if (!ms.VerifySignature(m_RemoteCertificate, signature))
{
throw new SslException(AlertDescription.HandshakeFailure, "The data was not signed by the server certificate.");
}
ms.Clear();
return(new SslHandshakeStatus(SslStatus.MessageIncomplete, null));
}
// Thanks to Brandon for notifying us about a bug in this method
public override SslHandshakeStatus ProcessSsl2Hello(byte[] hello)
{
if (m_State != HandshakeType.Nothing)
{
throw new SslException(AlertDescription.UnexpectedMessage, "SSL2 ClientHello message must be the first message.");
}
m_IsNegotiating = true;
m_State = HandshakeType.ClientHello;
UpdateHashes(hello, HashUpdate.All); // input message
// process ClientHello
ProtocolVersion pv = new ProtocolVersion(hello[1], hello[2]);
m_MaxClientVersion = pv;
if (CompatibilityLayer.SupportsProtocol(m_Options.Protocol, pv) && pv.GetVersionInt() != GetVersion().GetVersionInt())
{
throw new SslException(AlertDescription.IllegalParameter, "Unknown protocol version of the client.");
}
int csl = hello[3] * 256 + hello[4]; // cipher spec length
int sidl = hello[5] * 256 + hello[6]; // session id length
int cl = hello[7] * 256 + hello[8]; // challenge length
// process ciphers
byte[] ciphers = new byte[(csl / 3) * 2];
int offset = 10;
for (int i = 0; i < ciphers.Length; i += 2)
{
Array.Copy(hello, offset, ciphers, i, 2);
offset += 3;
}
m_EncryptionScheme = CipherSuites.GetCipherSuiteAlgorithm(ciphers, m_Options.AllowedAlgorithms);
// process session id
m_SessionID = new byte[sidl];
Array.Copy(hello, 9 + csl, m_SessionID, 0, sidl);
// process random data [challenge]
m_ClientTime = new byte[4];
m_ClientRandom = new byte[28];
if (cl <= 28)
{
Array.Copy(hello, 9 + csl + sidl, m_ClientRandom, m_ClientRandom.Length - cl, cl);
}
else
{
Array.Copy(hello, 9 + csl + sidl + (cl - 28), m_ClientRandom, 0, 28);
Array.Copy(hello, 9 + csl + sidl, m_ClientTime, 4 - (cl - 28), cl - 28);
}
m_CompressionMethod = SslAlgorithms.NULL_COMPRESSION;
return(GetClientHelloResult());
}
protected override byte[] GetClientHello()
{
if (m_State != HandshakeType.Nothing && m_State != HandshakeType.Finished)
{
throw new SslException(AlertDescription.UnexpectedMessage, "ClientHello message must be the first message or must be preceded by a Finished message.");
}
m_IsNegotiating = true;
m_State = HandshakeType.ClientHello;
byte[] ciphers = CipherSuites.GetCipherAlgorithmBytes(m_Options.AllowedAlgorithms);
byte[] compr = CompressionAlgorithm.GetCompressionAlgorithmBytes(m_Options.AllowedAlgorithms);
MemoryStream clientHello = new MemoryStream();
m_ClientTime = GetUnixTime();
m_ClientRandom = new byte[28];
m_RNG.GetBytes(m_ClientRandom);
ProtocolVersion pv = CompatibilityLayer.GetMaxProtocol(m_Options.Protocol);
clientHello.WriteByte(pv.major);
clientHello.WriteByte(pv.minor);
clientHello.Write(m_ClientTime, 0, m_ClientTime.Length);
clientHello.Write(m_ClientRandom, 0, m_ClientRandom.Length);
clientHello.WriteByte(0);
clientHello.WriteByte((byte)(ciphers.Length / 256));
clientHello.WriteByte((byte)(ciphers.Length % 256));
clientHello.Write(ciphers, 0, ciphers.Length);
clientHello.WriteByte((byte)compr.Length);
clientHello.Write(compr, 0, compr.Length);
if (this.clientHelloExts != null)
{
this.clientHelloExts.WriteExtensions(clientHello, ConnectionEnd.Client);
}
HandshakeMessage hm = new HandshakeMessage(HandshakeType.ClientHello, clientHello.ToArray());
byte[] ret = hm.ToBytes();
UpdateHashes(ret, HashUpdate.All); // client hello message
return(m_RecordLayer.EncryptBytes(ret, 0, ret.Length, ContentType.Handshake));
}
protected SslHandshakeStatus ProcessCertificateRequest(HandshakeMessage message)
{
if (m_State == HandshakeType.ServerKeyExchange)
{
CipherDefinition cd = CipherSuites.GetCipherDefinition(m_EncryptionScheme);
if (this.m_RemoteCertificate.GetPublicKeyLength() <= 512 || !cd.Exportable)
{
throw new SslException(AlertDescription.HandshakeFailure, "Invalid message.");
}
}
else if (m_State != HandshakeType.Certificate)
{
throw new SslException(AlertDescription.UnexpectedMessage, "CertificateRequest message must be preceded by a Certificate or ServerKeyExchange message.");
}
UpdateHashes(message, HashUpdate.All); // input message
// get supported certificate types
bool supportsRsaCerts = false;
byte[] certTypes = new byte[message.fragment[0]]; // currently we're not doing anything with the supported certificate types
Buffer.BlockCopy(message.fragment, 1, certTypes, 0, certTypes.Length);
for (int i = 0; i < certTypes.Length; i++)
{
if (certTypes[i] == 1) // rsa_sign
{
supportsRsaCerts = true;
break;
}
}
// get list of distinguished names
if (m_Options.RequestHandler != null && supportsRsaCerts) // make sure the client passed a delegate
{
Queue q = new Queue();
DistinguishedNameList r = new DistinguishedNameList();
int size, offset = message.fragment[0] + 3;
byte[] buffer;
while (offset < message.fragment.Length)
{
size = message.fragment[offset] * 256 + message.fragment[offset + 1];
buffer = new byte[size];
Buffer.BlockCopy(message.fragment, offset + 2, buffer, 0, size);
q.Enqueue(buffer);
offset += size + 2;
}
// decode RDN structures
while (q.Count > 0)
{
r.Add(ProcessName((byte[])q.Dequeue()));
}
RequestEventArgs e = new RequestEventArgs();
try {
m_Options.RequestHandler(Parent, r, e);
if (e.Certificate != null)
{
m_Options.Certificate = e.Certificate;
}
} catch (Exception de) {
throw new SslException(de, AlertDescription.InternalError, "The code in the CertRequestEventHandler delegate threw an error.");
}
}
if (!supportsRsaCerts)
{
m_Options.Certificate = null; // do not send client certificate
}
m_MutualAuthentication = true;
return(new SslHandshakeStatus(SslStatus.MessageIncomplete, null));
}
protected SslHandshakeStatus GetClientHelloResult()
{
MemoryStream retMessage = new MemoryStream();
SslHandshakeStatus ret = new SslHandshakeStatus();
HandshakeMessage temp;
byte[] bytes;
// ServerHello message
temp = new HandshakeMessage(HandshakeType.ServerHello, new byte[38]);
m_ServerTime = GetUnixTime();
m_ServerRandom = new byte[28];
m_RNG.GetBytes(m_ServerRandom);
temp.fragment[0] = GetVersion().major;
temp.fragment[1] = GetVersion().minor;
Array.Copy(m_ServerTime, 0, temp.fragment, 2, 4);
Array.Copy(m_ServerRandom, 0, temp.fragment, 6, 28);
temp.fragment[34] = 0; // do not resume a session, and do not let the other side cache it
Array.Copy(CipherSuites.GetCipherAlgorithmBytes(m_EncryptionScheme), 0, temp.fragment, 35, 2);
temp.fragment[37] = CompressionAlgorithm.GetAlgorithmByte(m_CompressionMethod);
bytes = temp.ToBytes();
retMessage.Write(bytes, 0, bytes.Length);
// Certificate message
byte[] certs = GetCertificateList(m_Options.Certificate);
temp.type = HandshakeType.Certificate;
temp.fragment = certs;
bytes = temp.ToBytes();
retMessage.Write(bytes, 0, bytes.Length);
// ServerKeyExchange message [optional] => only with RSA_EXPORT and public key > 512 bits
if (m_Options.Certificate.GetPublicKeyLength() > 512 && CipherSuites.GetCipherDefinition(m_EncryptionScheme).Exportable)
{
MemoryStream kes = new MemoryStream();
MD5SHA1CryptoServiceProvider mscsp = new MD5SHA1CryptoServiceProvider();
// hash the client and server random values
mscsp.TransformBlock(m_ClientTime, 0, 4, m_ClientTime, 0);
mscsp.TransformBlock(m_ClientRandom, 0, 28, m_ClientRandom, 0);
mscsp.TransformBlock(m_ServerTime, 0, 4, m_ServerTime, 0);
mscsp.TransformBlock(m_ServerRandom, 0, 28, m_ServerRandom, 0);
// create a new 512 bit RSA key
m_KeyCipher = new RSACryptoServiceProvider(512);
RSAParameters p = m_KeyCipher.ExportParameters(false);
// write the key parameters to the output stream
bytes = new byte[] { (byte)(p.Modulus.Length / 256), (byte)(p.Modulus.Length % 256) };
kes.Write(bytes, 0, 2);
kes.Write(p.Modulus, 0, p.Modulus.Length);
mscsp.TransformBlock(bytes, 0, 2, bytes, 0);
mscsp.TransformBlock(p.Modulus, 0, p.Modulus.Length, p.Modulus, 0);
bytes = new byte[] { (byte)(p.Exponent.Length / 256), (byte)(p.Exponent.Length % 256) };
kes.Write(bytes, 0, 2);
kes.Write(p.Exponent, 0, p.Exponent.Length);
mscsp.TransformBlock(bytes, 0, 2, bytes, 0);
mscsp.TransformFinalBlock(p.Exponent, 0, p.Exponent.Length);
// create signature
bytes = mscsp.CreateSignature(m_Options.Certificate);
kes.Write(new byte[] { (byte)(bytes.Length / 256), (byte)(bytes.Length % 256) }, 0, 2);
kes.Write(bytes, 0, bytes.Length);
// write to output
temp.type = HandshakeType.ServerKeyExchange;
temp.fragment = kes.ToArray();
bytes = temp.ToBytes();
retMessage.Write(bytes, 0, bytes.Length);
kes.Close();
}
else
{
m_KeyCipher = (RSACryptoServiceProvider)m_Options.Certificate.PrivateKey;
}
// CertificateRequest message [optional]
if (m_MutualAuthentication)
{
bytes = GetDistinguishedNames();
if (bytes.Length != 0) // make sure at least one certificate is returned
{
temp.type = HandshakeType.CertificateRequest;
temp.fragment = new byte[bytes.Length + 4];
temp.fragment[0] = 1; // one certificate type supported
temp.fragment[1] = 1; // cert type RSA
temp.fragment[2] = (byte)(bytes.Length / 256);
temp.fragment[3] = (byte)(bytes.Length % 256);
Array.Copy(bytes, 0, temp.fragment, 4, bytes.Length);
bytes = temp.ToBytes();
retMessage.Write(bytes, 0, bytes.Length);
}
}
// ServerHelloDone message
temp.type = HandshakeType.ServerHelloDone;
temp.fragment = new byte[0];
bytes = temp.ToBytes();
retMessage.Write(bytes, 0, bytes.Length);
// final adjustments
ret.Status = SslStatus.ContinueNeeded;
ret.Message = retMessage.ToArray();
retMessage.Close();
UpdateHashes(ret.Message, HashUpdate.All); // output message
ret.Message = m_RecordLayer.EncryptBytes(ret.Message, 0, ret.Message.Length, ContentType.Handshake);
return(ret);
}
protected SslHandshakeStatus ProcessClientHello(HandshakeMessage message)
{
if (m_State != HandshakeType.Nothing && m_State != HandshakeType.Finished)
{
throw new SslException(AlertDescription.UnexpectedMessage, "ClientHello message must be the first message or must be preceded by a Finished message.");
}
Alert alert = null;
m_IsNegotiating = true;
UpdateHashes(message, HashUpdate.All); // input message
// process ClientHello
int currentLen = 0;
ProtocolVersion pv = new ProtocolVersion(message.fragment[currentLen++], message.fragment[currentLen++]);
m_MaxClientVersion = pv;
//Violation with tls spec. If remote side uses higher protocol version than your, then we must answer with your highest version
//if (CompatibilityLayer.SupportsProtocol(m_Options.Protocol, pv) && pv.GetVersionInt() != GetVersion().GetVersionInt())
// throw new SslException(AlertDescription.IllegalParameter, "Unknown protocol version of the client.");
try {
// extract the time from the client [== 1 uint]
m_ClientTime = new byte[4];
Buffer.BlockCopy(message.fragment, currentLen, m_ClientTime, 0, 4);
currentLen += 4;
// extract the random bytes [== 28 bytes]
m_ClientRandom = new byte[28];
Buffer.BlockCopy(message.fragment, currentLen, m_ClientRandom, 0, 28);
currentLen += 28;
// extact the session ID [== 0..32 bytes]
byte length = message.fragment[currentLen++];
if (length > 32)
{
throw new SslException(AlertDescription.IllegalParameter, "The length of the SessionID cannot be more than 32 bytes.");
}
m_SessionID = new byte[length];
Buffer.BlockCopy(message.fragment, currentLen, m_SessionID, 0, length);
currentLen += length;
// extract the available cipher suites
Int16 ciphers_size = BinaryHelper.Int16FromBytes(message.fragment[currentLen++], message.fragment[currentLen++]);//message.fragment[length] * 256 + message.fragment[length + 1];
if (ciphers_size < 2 || ciphers_size % 2 != 0)
{
throw new SslException(AlertDescription.IllegalParameter, "The number of ciphers is invalid -or- the cipher length is not even.");
}
byte[] ciphers = new byte[ciphers_size];
Buffer.BlockCopy(message.fragment, currentLen, ciphers, 0, ciphers_size);
currentLen += ciphers_size;
m_EncryptionScheme = CipherSuites.GetCipherSuiteAlgorithm(ciphers, m_Options.AllowedAlgorithms);
// extract the available compression algorithms
int compressors_size = message.fragment[currentLen++];
if (compressors_size == 0)
{
throw new SslException(AlertDescription.IllegalParameter, "No compressor specified.");
}
byte[] compressors = new byte[compressors_size];
Buffer.BlockCopy(message.fragment, currentLen, compressors, 0, compressors_size);
m_CompressionMethod = CompressionAlgorithm.GetCompressionAlgorithm(compressors, m_Options.AllowedAlgorithms);
currentLen += compressors_size;
try
{
if (message.fragment.Length > currentLen)
{
this.ProcessExtensions(message.fragment, ref currentLen, ConnectionEnd.Server);
}
}
catch (ALPNCantSelectProtocolException ex)
{
alert = new Alert(ex.Description, ex.Level);
}
} catch (Exception e) {
throw new SslException(e, AlertDescription.InternalError, "The message is invalid.");
}
// create reply
return(GetClientHelloResult(alert));
}