private Tuple <string, byte[]> ReturnError(int state, ErrorCodes error)
{
var tlvData = new Tlv();
tlvData.AddType(Constants.State, state++);
tlvData.AddType(Constants.Error, error);
byte[] output = TlvParser.Serialise(tlvData);
return(new Tuple <string, byte[]>("application/pairing+tlv8", output));
}
public PairSetupReturn Post(Tlv parts)
{
var customParams = SrpParameters.Create3072 <SHA512>();
var state = parts.GetTypeAsInt(Constants.State);
if (state == 1) //srp sign up
{
var rnd = new Random();
_salt = new byte[16];
rnd.NextBytes(_salt);
_saltInt = SrpInteger.FromByteArray(_salt);
var srp = new SrpClient(customParams);
_privateKey = srp.DerivePrivateKey(_saltInt.ToHex(), Username, _code);
_verifier = srp.DeriveVerifier(_privateKey);
_server = new SrpServer(customParams);
_serverEphemeral = _server.GenerateEphemeral(_verifier);
var responseTlv = new Tlv();
responseTlv.AddType(Constants.State, 2);
responseTlv.AddType(Constants.PublicKey, StringToByteArray(_serverEphemeral.Public));
responseTlv.AddType(Constants.Salt, _salt);
return(new PairSetupReturn
{
State = 1,
TlvData = responseTlv,
Ok = true
});
}
if (state == 3) //srp authenticate
{
_logger.LogDebug("Pair Setup Step 3/6");
_logger.LogDebug("SRP Verify Request");
var pubKey = parts.GetType(Constants.PublicKey);
var proof = parts.GetType(Constants.Proof);
var iOsPublicKey = SrpInteger.FromByteArray(pubKey);
var iOsProof = SrpInteger.FromByteArray(proof);
var responseTlv = new Tlv();
responseTlv.AddType(Constants.State, 4);
var ok = true;
try
{
_serverSession = _server.DeriveSession(_serverEphemeral.Secret, iOsPublicKey.ToHex(), _saltInt.ToHex(), Username, _verifier,
iOsProof.ToHex());
_logger.LogInformation("Verification was successful. Generating Server Proof (M2)");
responseTlv.AddType(Constants.Proof, StringToByteArray(_serverSession.Proof));
}
catch (Exception)
{
ok = false;
_logger.LogError("Verification failed as iOS provided code was incorrect");
responseTlv.AddType(Constants.Error, ErrorCodes.Authentication);
}
return(new PairSetupReturn
{
State = 3,
Ok = ok,
TlvData = responseTlv
});
}
if (state == 5)
{
_logger.LogDebug("Pair Setup Step 5/6");
_logger.LogDebug("Exchange Response");
try
{
var iOsEncryptedData = parts.GetType(Constants.EncryptedData).AsSpan(); // A
var zeros = new byte[] { 0, 0, 0, 0 };
var nonce = new Nonce(zeros, Encoding.UTF8.GetBytes("PS-Msg05"));
var hdkf = new HkdfSha512();
var hkdfEncKey = hdkf.DeriveBytes(
SharedSecret.Import(SrpInteger.FromHex(_serverSession.Key).ToByteArray()),
Encoding.UTF8.GetBytes("Pair-Setup-Encrypt-Salt"),
Encoding.UTF8.GetBytes("Pair-Setup-Encrypt-Info"), 32);
var decrypt = AeadAlgorithm.ChaCha20Poly1305.Decrypt(
Key.Import(AeadAlgorithm.ChaCha20Poly1305, hkdfEncKey, KeyBlobFormat.RawSymmetricKey), nonce,
new byte[0], iOsEncryptedData, out var output);
var responseTlv = new Tlv();
responseTlv.AddType(Constants.State, 6);
if (!decrypt)
{
responseTlv.AddType(Constants.Error, ErrorCodes.Authentication);
return(new PairSetupReturn
{
State = 5,
TlvData = responseTlv,
Ok = false
});
}
var subData = TlvParser.Parse(output);
byte[] username = subData.GetType(Constants.Identifier);
byte[] ltpk = subData.GetType(Constants.PublicKey);
byte[] proof = subData.GetType(Constants.Signature);
var okm = hdkf.DeriveBytes(
SharedSecret.Import(SrpInteger.FromHex(_serverSession.Key).ToByteArray()),
Encoding.UTF8.GetBytes("Pair-Setup-Controller-Sign-Salt"),
Encoding.UTF8.GetBytes("Pair-Setup-Controller-Sign-Info"), 32);
var completeData = okm.Concat(username).Concat(ltpk).ToArray();
if (!SignatureAlgorithm.Ed25519.Verify(
PublicKey.Import(SignatureAlgorithm.Ed25519, ltpk, KeyBlobFormat.RawPublicKey), completeData,
proof))
{
var errorTlv = new Tlv();
errorTlv.AddType(Constants.Error, ErrorCodes.Authentication);
return(new PairSetupReturn
{
State = 5,
TlvData = errorTlv,
Ok = false
});
}
var accessory = hdkf.DeriveBytes(
SharedSecret.Import(SrpInteger.FromHex(_serverSession.Key).ToByteArray()),
Encoding.UTF8.GetBytes("Pair-Setup-Accessory-Sign-Salt"),
Encoding.UTF8.GetBytes("Pair-Setup-Accessory-Sign-Info"), 32);
var seed = new byte[32];
RandomNumberGenerator.Create().GetBytes(seed);
Chaos.NaCl.Ed25519.KeyPairFromSeed(out var accessoryLtpk, out var accessoryLtsk, seed);
var serverUsername = Encoding.UTF8.GetBytes(HapControllerServer.HapControllerId);
var material = accessory.Concat(serverUsername).Concat(accessoryLtpk).ToArray();
var signature = Chaos.NaCl.Ed25519.Sign(material, accessoryLtsk);
var encoder = new Tlv();
encoder.AddType(Constants.Identifier, serverUsername);
encoder.AddType(Constants.PublicKey, accessoryLtpk);
encoder.AddType(Constants.Signature, signature);
var plaintext = TlvParser.Serialise(encoder);
var nonce6 = new Nonce(zeros, Encoding.UTF8.GetBytes("PS-Msg06"));
var encryptedOutput = AeadAlgorithm.ChaCha20Poly1305.Encrypt(
Key.Import(AeadAlgorithm.ChaCha20Poly1305, hkdfEncKey, KeyBlobFormat.RawSymmetricKey), nonce6,
new byte[0], plaintext);
responseTlv.AddType(Constants.EncryptedData, encryptedOutput);
return(new PairSetupReturn
{
State = 5,
TlvData = responseTlv,
Ok = true,
Ltsk = ByteArrayToString(accessoryLtsk),
Ltpk = ByteArrayToString(ltpk)
});
}
catch (Exception e)
{
_logger.LogError(e, "Could not exchange request");
throw;
}
}
return(null);
}
public Tuple <string, byte[]> Invoke(string connectionId, string url, string method, byte[] inputData)
{
if (!_sessions.ContainsKey(connectionId))
{
_sessions.Add(connectionId, new HapSession());
}
var queryString = new NameValueCollection();
if (url.Contains("?"))
{
var parts = url.Split('?');
queryString = HttpUtility.ParseQueryString(parts[1]);
url = parts[0];
}
try
{
if (inputData.Length > 0)
{
var parts = TlvParser.Parse(inputData);
if (method == "POST")
{
var state = parts.GetTypeAsInt(Constants.State);
if (url.EndsWith("pair-setup"))
{
if (_pairController != null && state == 1)
{
return(ReturnError(state, ErrorCodes.Busy));
}
if (state == 1 && _pairController == null)
{
_pairController =
new PairSetupController(_logger, _pairCode); //Todo: change code to param
}
var data = _pairController.Post(parts);
var raw = TlvParser.Serialise(data.TlvData);
if (!data.Ok)
{
_pairController = null;
_sessions.Remove(connectionId);
}
else if (data.State == 5)
{
PairingCompleted?.Invoke(this, new PairSetupCompleteEventArgs(data.Ltsk, data.Ltpk));
_pairController = null;
}
return(new Tuple <string, byte[]>(data.ContentType, raw));
}
if (url.EndsWith("pair-verify"))
{
if (string.IsNullOrEmpty(HapControllerServer.HapControllerLtsk))
{
return(ReturnError(state, ErrorCodes.Busy));
}
var verify = new PairVerifyController(_logger);
var data = verify.Post(parts, _sessions[connectionId]);
if (data.HapSession != null)
{
_sessions[connectionId] = data.HapSession;
}
var raw = TlvParser.Serialise(data.TlvData);
return(new Tuple <string, byte[]>(data.ContentType, raw));
}
if (url.EndsWith("pairings"))
{
var pair = new PairingController(_logger);
var data = pair.Post(parts);
var raw = TlvParser.Serialise(data.TlvData);
return(new Tuple <string, byte[]>(data.ContentType, raw));
}
if (url.EndsWith("identify"))
{
var identify = new IdentifyController();
var data = identify.Post(inputData);
return(new Tuple <string, byte[]>(data.ContentType, new byte[0]));
}
}
else if (method == "PUT")
{
if (url.EndsWith("characteristics"))
{
var c = new CharacteristicsController(_logger);
var data = c.Put(inputData, _sessions[connectionId], _homeKitServer);
if (data.Characteristics.Count == 0)
{
return(new Tuple <string, byte[]>(data.ContentType, new byte[0]));
}
return(new Tuple <string, byte[]>(data.ContentType, Encoding.UTF8.GetBytes(JsonConvert.SerializeObject(data))));
}
}
}
else
{
if (method == "GET")
{
if (url.EndsWith("accessories"))
{
var accessoryController = new AccesoriesController();
var accessories = accessoryController.Get(_homeKitServer, queryString);
var strValue = JsonConvert.SerializeObject(accessories, JsonSettings);
return(new Tuple <string, byte[]>("application/hap+json", Encoding.UTF8.GetBytes(strValue)));
}
if (url.EndsWith("characteristics"))
{
var ids = queryString["id"].Split(",");
var c = new CharacteristicsController(_logger);
var data = c.Get(ids, _homeKitServer);
return(new Tuple <string, byte[]>(data.ContentType, Encoding.UTF8.GetBytes(JsonConvert.SerializeObject(data, JsonSettings))));
}
}
}
}
catch (Exception e)
{
_logger.LogError(e, "Error occured while processing request");
_pairController = null;
}
throw new InvalidOperationException();
}
public PairVerifyReturn Post(Tlv parts, HapSession session)
{
var state = parts.GetTypeAsInt(Constants.State);
if (state == 1)
{
_logger.LogDebug("* Pair Verify Step 1/4");
_logger.LogDebug("* Verify Start Request");
var clientPublicKey = parts.GetType(Constants.PublicKey);
byte[] privateKey = new byte[32];
Random random = new Random();
random.NextBytes(privateKey);
var publicKey = Curve25519.GetPublicKey(privateKey);
var sharedSecret = Curve25519.GetSharedSecret(privateKey, clientPublicKey);
var serverUsername = Encoding.UTF8.GetBytes(HapControllerServer.HapControllerId);
var material = publicKey.Concat(serverUsername).Concat(clientPublicKey).ToArray();
var accessoryLtsk = StringToByteArray(HapControllerServer.HapControllerLtsk);
var proof = Ed25519.Sign(material, accessoryLtsk);
var hdkf = new HkdfSha512();
var hkdfEncKey = hdkf.DeriveBytes(SharedSecret.Import(sharedSecret), Encoding.UTF8.GetBytes("Pair-Verify-Encrypt-Salt"),
Encoding.UTF8.GetBytes("Pair-Verify-Encrypt-Info"), 32);
var encoder = new Tlv();
encoder.AddType(Constants.Identifier, serverUsername);
encoder.AddType(Constants.Signature, proof);
var plaintext = TlvParser.Serialise(encoder);
var zeros = new byte[] { 0, 0, 0, 0 };
var nonce = new Nonce(zeros, Encoding.UTF8.GetBytes("PV-Msg02"));
var encryptedOutput = AeadAlgorithm.ChaCha20Poly1305.Encrypt(
Key.Import(AeadAlgorithm.ChaCha20Poly1305, hkdfEncKey, KeyBlobFormat.RawSymmetricKey), nonce,
new byte[0], plaintext);
var responseTlv = new Tlv();
responseTlv.AddType(Constants.State, 2);
responseTlv.AddType(Constants.EncryptedData, encryptedOutput);
responseTlv.AddType(Constants.PublicKey, publicKey);
// Store the details on the session.
//
session.ClientPublicKey = clientPublicKey;
session.PrivateKey = privateKey;
session.PublicKey = publicKey;
session.SharedSecret = sharedSecret;
session.HkdfPairEncKey = hkdfEncKey;
var encSalt = Encoding.UTF8.GetBytes("Control-Salt");
var infoRead = Encoding.UTF8.GetBytes("Control-Read-Encryption-Key");
var infoWrite = Encoding.UTF8.GetBytes("Control-Write-Encryption-Key");
session.AccessoryToControllerKey = hdkf.DeriveBytes(SharedSecret.Import(sharedSecret), encSalt, infoRead, 32);
session.ControllerToAccessoryKey = hdkf.DeriveBytes(SharedSecret.Import(sharedSecret), encSalt, infoWrite, 32);
return(new PairVerifyReturn
{
TlvData = responseTlv,
Ok = true,
HapSession = session
});
}
if (state == 3)
{
_logger.LogDebug("* Pair Verify Step 3/4");
_logger.LogDebug("* Verify Finish Request");
var encryptedData = parts.GetType(Constants.EncryptedData);
var zeros = new byte[] { 0, 0, 0, 0 };
var nonce = new Nonce(zeros, Encoding.UTF8.GetBytes("PV-Msg03"));
var decrypt = AeadAlgorithm.ChaCha20Poly1305.Decrypt(Key.Import(AeadAlgorithm.ChaCha20Poly1305, session.HkdfPairEncKey, KeyBlobFormat.RawSymmetricKey), nonce, new byte[0], encryptedData, out var output);
if (!decrypt)
{
var errorTlv = new Tlv();
errorTlv.AddType(Constants.State, 4);
errorTlv.AddType(Constants.Error, ErrorCodes.Authentication);
return(new PairVerifyReturn
{
TlvData = errorTlv,
Ok = false
});
}
var subData = TlvParser.Parse(output);
var clientUserName = subData.GetType(Constants.Identifier);
var signature = subData.GetType(Constants.Signature);
var clientPublicKey = StringToByteArray(HapControllerServer.HapControllerLtpk);
var material = session.ClientPublicKey.Concat(clientUserName).Concat(session.PublicKey).ToArray();
if (!Ed25519.Verify(signature, material, clientPublicKey))
{
var errorTlv = new Tlv();
errorTlv.AddType(Constants.State, 4);
errorTlv.AddType(Constants.Error, ErrorCodes.Authentication);
return(new PairVerifyReturn
{
TlvData = errorTlv,
Ok = false
});
}
var responseTlv = new Tlv();
responseTlv.AddType(Constants.State, 4);
session.IsVerified = true;
session.SkipFirstEncryption = true;
return(new PairVerifyReturn
{
Ok = true,
TlvData = responseTlv
});
}
return(null);
}