public ExternalCertificate(ReadableBuffer buffer)
{
var reader = new BigEndianAdvancingSpan(buffer.ToSpan());
reader.Read <HandshakeHeader>();
reader = reader.ReadVector <UInt24>();
_certificate = new X509Certificate2(reader.ReadVector <UInt24>().ToArray());
if (reader.Length > 0)
{
_collection = new X509Certificate2Collection();
while (reader.Length > 0)
{
var cert = new X509Certificate2(reader.ReadVector <UInt24>().ToArray());
_collection.Add(cert);
}
}
Debug.Assert(reader.Length == 0);
_rsaPublicKey = _certificate.GetRSAPublicKey();
if (_rsaPublicKey != null)
{
_certificateType = CertificateType.rsa;
_signatureSize = _rsaPublicKey.KeySize / 8;
_certificateType = CertificateType.rsa;
return;
}
_ecdsaPublicKey = _certificate.GetECDsaPublicKey();
if (_ecdsaPublicKey != null)
{
_certificateType = CertificateType.ecdsa;
switch (_ecdsaPublicKey.KeySize)
{
case 256:
_signatureScheme = SignatureScheme.ecdsa_secp256r1_sha256;
_signatureSize = 72;
break;
case 384:
_signatureScheme = SignatureScheme.ecdsa_secp384r1_sha384;
throw new NotImplementedException();
case 521:
_signatureSize = 132;
_signatureScheme = SignatureScheme.ecdsa_secp521r1_sha512;
break;
default:
throw new InvalidOperationException($"Unsupported Ecdsa Keysize {_ecdsaPublicKey.KeySize}");
}
return;
}
}
public ServerHelloParser(ReadableBuffer buffer, SecurePipeConnection secureConnection)
{
_originalMessage = buffer.ToSpan();
var span = new BigEndianAdvancingSpan(_originalMessage);
span.Read <HandshakeHeader>();
_tlsVersion = span.Read <TlsVersion>();
_serverRandom = span.TakeSlice(TlsConstants.RandomLength).ToSpan();
_sessionId = span.ReadVector <byte>().ToSpan();
_cipherSuite = span.Read <ushort>();
var compression = span.Read <byte>(); //Dump compression
if (compression != 0)
{
Alerts.AlertException.ThrowAlert(Alerts.AlertLevel.Fatal, Alerts.AlertDescription.handshake_failure, "Compression is not supported");
}
_supportedGroups = default;
if (span.Length == 0)
{
return;
}
span = span.ReadVector <ushort>();
while (span.Length > 0)
{
var extType = span.Read <ExtensionType>();
var extBuffer = span.ReadVector <ushort>();
switch (extType)
{
case ExtensionType.supported_groups:
throw new NotImplementedException();
case ExtensionType.application_layer_protocol_negotiation:
throw new NotImplementedException();
case ExtensionType.server_name:
throw new NotImplementedException();
case ExtensionType.SessionTicket:
throw new NotImplementedException();
case ExtensionType.signature_algorithms:
throw new NotImplementedException();
case ExtensionType.renegotiation_info:
throw new NotImplementedException();
}
}
}
//This can be extended to check that we match a list of servernames
//or any other logic that is required
public string ProcessHostNameExtension(BigEndianAdvancingSpan buffer)
{
buffer = buffer.ReadVector <ushort>();
var type = buffer.Read <byte>();
if (type != 0)
{
Alerts.AlertException.ThrowDecode("Unknown host type");
}
buffer = buffer.ReadVector <ushort>();
return(string.Empty);// Ascii.ToUtf16String(buffer.ToSpan());
}
public SignatureScheme SelectAlgorithm(BigEndianAdvancingSpan buffer)
{
if (_certificateType == CertificateType.ecdsa)
{
return(_ecDsaSignatureScheme);
}
if (buffer.Length == 0)
{
return(DefaultSignatureScheme);
}
buffer = buffer.ReadVector <ushort>();
while (buffer.Length > 0)
{
var scheme = buffer.Read <SignatureScheme>();
var lastByte = 0x00FF & (ushort)scheme;
switch (_certificateType)
{
case CertificateType.rsa:
if (lastByte == 1)
{
return(scheme);
}
if ((0xFF00 & (ushort)scheme) == 0x0800 && lastByte > 3 && lastByte < 7)
{
return(scheme);
}
break;
}
}
Alerts.AlertException.ThrowAlert(Alerts.AlertLevel.Fatal, Alerts.AlertDescription.handshake_failure, "Failed to find an appropriate signature scheme");
return(SignatureScheme.none);
}
public void SetPeerKey(BigEndianAdvancingSpan peerKey, ICertificate certificate, SignatureScheme scheme)
{
peerKey = peerKey.ReadVector <ushort>();
var decryptedLength = certificate.Decrypt(scheme, peerKey.ToSpan(), peerKey.ToSpan());
peerKey = peerKey.TakeSlice(decryptedLength);
_premasterSecret = peerKey.ToArray();
}
public void SetPeerKey(BigEndianAdvancingSpan peerKey, ICertificate certificate, SignatureScheme scheme)
{
peerKey = peerKey.ReadVector <byte>();
if (peerKey.Length != _keyExchangeSize)
{
Alerts.AlertException.ThrowAlert(Alerts.AlertLevel.Fatal, Alerts.AlertDescription.illegal_parameter, $"The peer key is not the length of the keyexchange size {peerKey.Length} - {_keyExchangeSize}");
}
InternalSetPeerKey(peerKey.ToSpan());
}
public void SetPeerKey(BigEndianAdvancingSpan peerKey, ICertificate certificate, SignatureScheme scheme)
{
peerKey = peerKey.ReadVector <byte>();
if (peerKey.Length != _keyExchangeSize)
{
Alerts.AlertException.ThrowAlert(Alerts.AlertLevel.Fatal, Alerts.AlertDescription.decode_error, "Peer key is bad");
}
InternalSetPeerKey(peerKey.ToSpan());
}
public ServerKeyExchangeParser(ReadableBuffer reader)
{
var originalSpan = reader.ToSpan();
var span = new BigEndianAdvancingSpan(originalSpan);
span.Read <HandshakeHeader>();
_curveType = span.Read <ECCurveType>();
if (_curveType != ECCurveType.named_curve)
{
Alerts.AlertException.ThrowAlert(Alerts.AlertLevel.Fatal, Alerts.AlertDescription.handshake_failure, "We only support named curves");
}
_namedGroup = span.Read <NamedGroup>();
_key = span;
span.ReadVector <byte>();
var dataLength = originalSpan.Length - span.Length;
_data = originalSpan.Slice(4, dataLength - 4);
_signatureScheme = span.Read <SignatureScheme>();
_signature = span.ReadVector <ushort>().ToSpan();
Debug.Assert(span.Length == 0);
}
public (ICertificate, SignatureScheme) GetCertificate(BigEndianAdvancingSpan buffer)
{
buffer = buffer.ReadVector <ushort>();
while (buffer.Length > 0)
{
var scheme = buffer.Read <SignatureScheme>();
for (var i = 0; i < _certificates.Count; i++)
{
if (_certificates[i].SupportsScheme(scheme))
{
return(_certificates[i], scheme);
}
}
}
Alerts.AlertException.ThrowFailedHandshake("Failed to find a certificate and scheme that matches");
return(null, SignatureScheme.none);
}
private IKeyExchange EcdheKeyExchange(BigEndianAdvancingSpan supportedGroups)
{
if (supportedGroups.Length == 0)
{
return(GetEcdheKeyExchange(DefaultNamedGroup));
}
supportedGroups = supportedGroups.ReadVector <ushort>();
while (supportedGroups.Length > 0)
{
var namedGroup = supportedGroups.Read <NamedGroup>();
if (!_supportedNamedGroups.Contains(namedGroup))
{
continue;
}
var key = GetEcdheKeyExchange(namedGroup);
if (key != null)
{
return(key);
}
}
Alerts.AlertException.ThrowAlert(Alerts.AlertLevel.Fatal, Alerts.AlertDescription.handshake_failure, "Unable to match key exchange");
return(null);
}
public ClientHelloParser(ReadableBuffer buffer, SecurePipeConnection secureConnection)
{
_originalMessage = buffer.ToSpan();
var span = new BigEndianAdvancingSpan(_originalMessage);
span.Read <HandshakeHeader>();
_tlsVersion = span.Read <TlsVersion>();
_clientRandom = span.TakeSlice(TlsConstants.RandomLength).ToSpan();
_sessionId = span.ReadVector <byte>().ToSpan();
_cipherSuite = span.ReadVector <ushort>();
_compressionMethods = span.ReadVector <byte>().ToSpan();
_negotiatedAlpn = ApplicationLayerProtocolType.None;
_hostName = null;
if (span.Length == 0)
{
return;
}
var extensionSpan = new BigEndianAdvancingSpan(span.ReadVector <ushort>().ToSpan());
while (extensionSpan.Length > 0)
{
var extType = extensionSpan.Read <ExtensionType>();
var extBuffer = extensionSpan.ReadVector <ushort>();
switch (extType)
{
case ExtensionType.application_layer_protocol_negotiation:
_negotiatedAlpn = secureConnection.Listener.AlpnProvider.ProcessExtension(extBuffer);
break;
case ExtensionType.server_name:
_hostName = secureConnection.Listener.HostNameProvider.ProcessHostNameExtension(extBuffer);
break;
case ExtensionType.signature_algorithms:
_signatureAlgos = extBuffer;
break;
case ExtensionType.supported_groups:
_supportedGroups = extBuffer;
break;
case ExtensionType.SessionTicket:
_sessionTicket = extBuffer;
break;
case ExtensionType.psk_key_exchange_modes:
case ExtensionType.pre_shared_key:
case ExtensionType.supported_versions:
case ExtensionType.key_share:
break;
}
}
if (span.Length > 0)
{
ThrowBytesLeftOver();
}
}