/// <summary>
/// Sends a TLObject through the connection. Subscribe to <see cref="TLObjectReceivedEvent"/> so that you will get the response.
/// </summary>
/// <param name="TLObject">The TLObject to send</param>
public async Task Send(TLObject TLObject)
{
// Can't send a non-object
if (TLObject == null)
{
throw new ArgumentNullException(nameof(TLObject));
}
// Get the byte representation of the TLObject
var request = TLObject.Serialize();
using (var memoryStream = new MemoryStream(8 + 8 + 4 + request.Length))
using (var binaryWriter = new BinaryWriter(memoryStream))
{
binaryWriter.Write(0L);
binaryWriter.Write(State.GetNewMessageID());
binaryWriter.Write(request.Length);
binaryWriter.Write(request);
await Connection.Send(memoryStream.ToArray());
}
}
private void Sender_TLObjectReceivedEvent(object sender, TLObjectEventArgs e)
{
// Ignore any data that we aren't expecting
if (CurrentState == AuthenticationState.NotStarted)
{
Logger.Log(Logger.Level.Debug, $"Received authentication data unexpectedly. Skipping. Try restarting the connection.");
return;
}
else if (MTSender == null)
{
// How did we get here if there's no sender? Hmm?
var sad = new Exception("Unable to find a connection to Telegram. Skipping. Try restarting the connection.");
Logger.Log(sad);
Response.TrySetException(sad);
CurrentState = AuthenticationState.NotStarted;
return;
}
switch (CurrentState)
{
case AuthenticationState.PQRequest:
// Deserialize the data
var ResPQ = e.TLObject;
Logger.Log(Logger.Level.Debug, $"Received TLObject {ResPQ["_"]}.");
// Factorize the PQ into two prime factors and fail if we can't
if (!Helpers.FindPQ((byte[])ResPQ["pq"], out JToken factorizedPair))
{
var sad = new Exception($"Unable to find any valid factors of PQ: {ResPQ["pq"]}");
Logger.Log(sad);
Response.TrySetException(sad);
MTSender.TLObjectReceivedEvent -= Sender_TLObjectReceivedEvent;
CurrentState = AuthenticationState.NotStarted;
Logger.Log(Logger.Level.Debug, $"Unsubscribed from {nameof(MTSender.TLObjectReceivedEvent)} event");
Logger.Log(Logger.Level.Info, $"Auth aborted.");
return;
}
// Compile the PQ information
PQInnerData = schema.p_q_inner_data(new
{
pq = factorizedPair["pq"],
p = factorizedPair["min"],
q = factorizedPair["max"],
nonce = ResPQ["nonce"],
server_nonce = ResPQ["server_nonce"],
new_nonce = Helpers.GenerateRandomBytes(32)
});
// Encrypt the PQ information.
// NOTE: Because the server responded with potentially more than one fingerprint,
// this also returns the fingerprint that we are using.
(var fingerpint, var EncryptedInnerData) = MTProto.Crypto.RSA.Encrypt(ResPQ["server_public_key_fingerprints"].ToObject <long[]>(), PQInnerData.Serialize());
Logger.Log(Logger.Level.Debug, $"Using Public RSA Key: {fingerpint}");
// Get ready for the next response
CurrentState = AuthenticationState.ServerDHRequest;
Logger.Log(Logger.Level.Debug, $"Submitting PQ factor to server");
// Compile the rest of the information and send to the server for grading
MTSender.Send(schema.req_DH_params(new
{
nonce = ResPQ["nonce"],
server_nonce = ResPQ["server_nonce"],
p = factorizedPair["min"],
q = factorizedPair["max"],
public_key_fingerprint = fingerpint,
encrypted_data = EncryptedInnerData
}));
break;
case AuthenticationState.ServerDHRequest:
// Make sure we have all the needed info
if (PQInnerData == null)
{
var sad = new Exception("Unable to find the PQInnerData object from previous steps. Please restart the connection process");
Logger.Log(sad);
Response.TrySetException(sad);
MTSender.TLObjectReceivedEvent -= Sender_TLObjectReceivedEvent;
CurrentState = AuthenticationState.NotStarted;
Logger.Log(Logger.Level.Debug, $"Unsubscribed from {nameof(MTSender.TLObjectReceivedEvent)} event");
Logger.Log(Logger.Level.Info, $"Auth aborted.");
return;
}
// Deserialize the data
var ServerDHParams = e.TLObject;
Logger.Log(Logger.Level.Debug, $"Received TLObject {ServerDHParams["_"]}.");
// Determine the result
if ((string)ServerDHParams["_"] != "server_DH_params_ok")
{
// Aaaand we failed to handle things correctly
var sad = new Exception($"The server responded with a {ServerDHParams["_"]} response. We are unable to continue.");
Logger.Log(sad);
Response.TrySetException(sad);
MTSender.TLObjectReceivedEvent -= Sender_TLObjectReceivedEvent;
CurrentState = AuthenticationState.NotStarted;
Logger.Log(Logger.Level.Debug, $"Unsubscribed from {nameof(MTSender.TLObjectReceivedEvent)} event");
Logger.Log(Logger.Level.Info, $"Auth aborted.");
return;
}
Logger.Log(Logger.Level.Debug, $"Decrypting the DHInnerData");
var key = AES.GenerateKeyDataFromNonces((byte[])ServerDHParams["server_nonce"], (byte[])PQInnerData["new_nonce"]);
var plaintextAnswer = AES.DecryptAES(key, (byte[])ServerDHParams["encrypted_answer"]);
using (var memory = new MemoryStream(plaintextAnswer))
using (var reader = new BinaryReader(memory))
{
var hashsum = reader.ReadBytes(20);
ServerDHInnerData = TLObject.Deserialize(reader);
}
if (ServerDHInnerData == null)
{
var sad = new Exception("The server did not respond with valid DH Inner Data. We are unable to continue.");
Logger.Log(sad);
Response.TrySetException(sad);
MTSender.TLObjectReceivedEvent -= Sender_TLObjectReceivedEvent;
CurrentState = AuthenticationState.NotStarted;
Logger.Log(Logger.Level.Debug, $"Unsubscribed from {nameof(MTSender.TLObjectReceivedEvent)} event");
Logger.Log(Logger.Level.Info, $"Auth aborted.");
return;
}
if ((string)ServerDHInnerData["_"] != "server_DH_inner_data")
{
var sad = new Exception($"The server responded with a {ServerDHInnerData["_"]} response. We are unable to continue.");
Logger.Log(sad);
Response.TrySetException(sad);
MTSender.TLObjectReceivedEvent -= Sender_TLObjectReceivedEvent;
CurrentState = AuthenticationState.NotStarted;
Logger.Log(Logger.Level.Debug, $"Unsubscribed from {nameof(MTSender.TLObjectReceivedEvent)} event");
Logger.Log(Logger.Level.Info, $"Auth aborted.");
return;
}
Logger.Log(Logger.Level.Debug, $"Decrypted TLObject {ServerDHInnerData["_"]}.");
TimeOffset = (int)ServerDHInnerData["server_time"] - (int)(DateTime.UtcNow - new DateTime(1970, 1, 1)).TotalSeconds;
Logger.Log(Logger.Level.Debug, $"Updated Time Offset {TimeOffset}.");
Logger.Log(Logger.Level.Debug, $"Calculating GAB");
var b = new BigInteger(1, Helpers.GenerateRandomBytes(256));
var gb = BigInteger.ValueOf((int)ServerDHInnerData["g"]).ModPow(b, new BigInteger(1, (byte[])ServerDHInnerData["dh_prime"]));
gab = new BigInteger(1, (byte[])ServerDHInnerData["g_a"]).ModPow(b, new BigInteger(1, (byte[])ServerDHInnerData["dh_prime"]));
TLObject ClientDHInnerData = schema.client_DH_inner_data(new
{
nonce = ServerDHInnerData["nonce"],
server_nonce = ServerDHInnerData["server_nonce"],
retry_id = 0L,
g_b = gb.ToByteArrayUnsigned()
});
var ClientDHInnerData_raw = ClientDHInnerData.Serialize();
byte[] ClientDHInnerDataHash = null;
using (var memory = new MemoryStream())
using (var writer = new BinaryWriter(memory))
using (var sha = SHA1.Create())
{
writer.Write(sha.ComputeHash(ClientDHInnerData_raw));
writer.Write(ClientDHInnerData_raw);
ClientDHInnerDataHash = memory.ToArray();
}
Logger.Log(Logger.Level.Debug, $"Sending ClientDHRequest");
// Get ready to the next response
CurrentState = AuthenticationState.ClientDHRequest;
MTSender.Send(schema.set_client_DH_params(new
{
nonce = ServerDHInnerData["nonce"],
server_nonce = ServerDHInnerData["server_nonce"],
encrypted_data = AES.EncryptAES(key, ClientDHInnerDataHash)
}));
break;
case AuthenticationState.ClientDHRequest:
// Make sure we have all the needed info
if (gab == null)
{
var sad = new Exception("Unable to find the GAB object from previous steps. Please restart the connection process");
Logger.Log(sad);
Response.TrySetException(sad);
MTSender.TLObjectReceivedEvent -= Sender_TLObjectReceivedEvent;
CurrentState = AuthenticationState.NotStarted;
Logger.Log(Logger.Level.Debug, $"Unsubscribed from {nameof(MTSender.TLObjectReceivedEvent)} event");
Logger.Log(Logger.Level.Info, $"Auth aborted.");
return;
}
else if (TimeOffset == null)
{
var sad = new Exception("Unable to find the TimeOffset from previous steps. Please restart the connection process");
Logger.Log(sad);
Response.TrySetException(sad);
MTSender.TLObjectReceivedEvent -= Sender_TLObjectReceivedEvent;
CurrentState = AuthenticationState.NotStarted;
Logger.Log(Logger.Level.Debug, $"Unsubscribed from {nameof(MTSender.TLObjectReceivedEvent)} event");
Logger.Log(Logger.Level.Info, $"Auth aborted.");
return;
}
var SetClientDHParamsAnswer = e.TLObject;
var AuthKey = new AuthKey(gab);
var newNonceHashCalculated = AuthKey.CalcNewNonceHash((byte[])PQInnerData["new_nonce"], 1);
Logger.Log(Logger.Level.Debug, $"Received TLObject {SetClientDHParamsAnswer["_"]}.");
if (!((byte[])SetClientDHParamsAnswer["new_nonce_hash1"]).SequenceEqual(newNonceHashCalculated))
{
var sad = new Exception("The server returned an invalid new nonce hash 1. Please restart the connection process");
Logger.Log(sad);
Response.TrySetException(sad);
MTSender.TLObjectReceivedEvent -= Sender_TLObjectReceivedEvent;
CurrentState = AuthenticationState.NotStarted;
Logger.Log(Logger.Level.Debug, $"Unsubscribed from {nameof(MTSender.TLObjectReceivedEvent)} event");
Logger.Log(Logger.Level.Info, $"Auth aborted.");
return;
}
Logger.Log(Logger.Level.Info, $"Successfully negotiated authorization with the server");
MTSender.TLObjectReceivedEvent -= Sender_TLObjectReceivedEvent;
Response.TrySetResult(new ServerAuthentication
{
AuthKey = AuthKey,
TimeOffset = (int)TimeOffset
});
break;
}
}
public RequestState(TLObject Request)
{
this.Request = Request;
Data = Request.Serialize();
Response = new TaskCompletionSource <TLObject>();
}
