private void VerifyResponseSignature(FidoAppId appId, FidoRegistrationData registrationData, FidoClientData clientData)
{
if (appId == null)
{
throw new ArgumentNullException("appId");
}
if (registrationData == null)
{
throw new ArgumentNullException("registrationData");
}
if (clientData == null)
{
throw new ArgumentNullException("clientData");
}
if (String.IsNullOrEmpty(clientData.RawJsonValue))
{
throw new InvalidOperationException("Client data has no JSON representation");
}
var signedBytes = PackBytes(
new byte[] { 0 },
Helpers.Sha256(appId.ToString()),
Helpers.Sha256(clientData.RawJsonValue),
registrationData.KeyHandle.ToByteArray(),
registrationData.UserPublicKey.ToByteArray());
VerifySignature(registrationData.AttestationCertificate, registrationData.Signature, signedBytes);
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
var jsonObject = JObject.Load(reader);
var properties = jsonObject.Properties().ToLookup(x => x.Name.ToLowerInvariant());
var serializedRegistrationData = properties["registrationdata"].Single().Value.ToString();
var serializedClientData = properties["clientdata"].Single().Value.ToString();
return(new FidoRegisterResponse
{
RegistrationData = FidoRegistrationData.FromWebSafeBase64(serializedRegistrationData),
ClientData = FidoClientData.FromWebSafeBase64(serializedClientData)
});
}
private static FidoRegistrationData FromStream(Stream stream)
{
if (stream == null)
{
throw new ArgumentNullException("stream");
}
using (var binaryReader = new BinaryReader(stream))
{
var reservedByte = binaryReader.ReadByte();
if (reservedByte != RegistrationReservedByte)
{
throw new InvalidOperationException(String.Format(
"Incorrect value of reserved byte (expected: 0x{0:X2} but was: 0x{1:X1})",
RegistrationReservedByte, reservedByte));
}
try
{
var publicKeyBytes = binaryReader.ReadBytes(65);
var keyHandleLength = binaryReader.ReadByte();
var keyHandleBytes = binaryReader.ReadBytes(keyHandleLength);
var nextChunkSize = (int)(binaryReader.BaseStream.Length - binaryReader.BaseStream.Position);
var certificatePosition = binaryReader.BaseStream.Position;
var certBytes = binaryReader.ReadBytes(nextChunkSize);
var certificate = new FidoAttestationCertificate(certBytes);
var certSize = certificate.Certificate.GetEncoded().Length;
binaryReader.BaseStream.Position = certificatePosition + certSize;
nextChunkSize = (int)(binaryReader.BaseStream.Length - binaryReader.BaseStream.Position);
var signatureBytes = binaryReader.ReadBytes(nextChunkSize);
var registerResponse = new FidoRegistrationData(
new FidoPublicKey(publicKeyBytes),
new FidoKeyHandle(keyHandleBytes),
certificate,
new FidoSignature(signatureBytes));
return(registerResponse);
}
catch (Exception ex)
{
var message = String.Format("Error parsing registration data ({0})", ex.Message);
throw new InvalidOperationException(message, ex);
}
}
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
return(FidoRegistrationData.FromWebSafeBase64(reader.Value.ToString()));
}