diff --git a/.github/dev.yml b/.github/dev.yml index 7119f2c..4ca6a83 100644 --- a/.github/dev.yml +++ b/.github/dev.yml @@ -2,7 +2,7 @@ pr: none trigger: - master -name: 1.8.4-dev.$(Rev:r) +name: 1.9.1-dev.$(Rev:r) pool: vmImage: ubuntu-latest diff --git a/.github/release.yml b/.github/release.yml index bf2f148..96cf785 100644 --- a/.github/release.yml +++ b/.github/release.yml @@ -1,7 +1,7 @@ pr: none trigger: none -name: 1.8.$(Rev:r) +name: 1.9.$(Rev:r) pool: vmImage: ubuntu-latest diff --git a/src/Client.cs b/src/Client.cs index b1c5f50..5130676 100644 --- a/src/Client.cs +++ b/src/Client.cs @@ -12,6 +12,7 @@ using System.Security.Cryptography; using System.Text; using System.Threading; using System.Threading.Tasks; +using System.Web; using TL; using static WTelegram.Encryption; @@ -25,7 +26,7 @@ namespace WTelegram /// This event will be called when an unsollicited update/message is sent by Telegram servers /// See Examples/Program_ListenUpdate.cs for how to use this public event Action Update; - public delegate Task TcpFactory(string address, int port); + public delegate Task TcpFactory(string host, int port); /// Used to create a TcpClient connected to the given address/port, or throw an exception on failure public TcpFactory TcpHandler = DefaultTcpHandler; /// Telegram configuration, obtained at connection time @@ -40,6 +41,9 @@ namespace WTelegram public bool IsMainDC => (_dcSession?.DataCenter?.id ?? 0) == _session.MainDC; /// Has this Client established connection been disconnected? public bool Disconnected => _tcpClient != null && !(_tcpClient.Client?.Connected ?? false); + /// Url for using a MTProxy. http://t.me/proxy?server=... + public string MTProxyUrl { get; set; } + /// Used to indicate progression of file download/upload /// total size of file in bytes, or 0 if unknown public delegate void ProgressCallback(long transmitted, long totalSize); @@ -49,7 +53,6 @@ namespace WTelegram private readonly string _apiHash; private readonly Session _session; private Session.DCSession _dcSession; - private static readonly byte[] IntermediateHeader = new byte[4] { 0xee, 0xee, 0xee, 0xee }; private TcpClient _tcpClient; private NetworkStream _networkStream; private IObject _lastSentMsg; @@ -75,6 +78,10 @@ namespace WTelegram private readonly SHA256 _sha256 = SHA256.Create(); private readonly SHA256 _sha256Recv = SHA256.Create(); #endif +#if OBFUSCATION + private AesCtr _sendCtr, _recvCtr; +#endif + private bool _paddedMode; /// Welcome to WTelegramClient! 🙂 /// Config callback, is queried for: api_id, api_hash, session_pathname @@ -93,6 +100,7 @@ namespace WTelegram private Client(Client cloneOf, Session.DCSession dcSession) { + MTProxyUrl = cloneOf.MTProxyUrl; _config = cloneOf._config; _apiId = cloneOf._apiId; _apiHash = cloneOf._apiHash; @@ -169,6 +177,11 @@ namespace WTelegram _sendSemaphore = new(0); _reactorTask = null; _tcpClient?.Dispose(); +#if OBFUSCATION + _sendCtr?.Dispose(); + _recvCtr?.Dispose(); +#endif + _paddedMode = false; _connecting = null; if (resetSessions) { @@ -210,62 +223,99 @@ namespace WTelegram private async Task DoConnectAsync() { - var endpoint = _dcSession?.EndPoint ?? Compat.IPEndPoint_Parse(Config("server_address")); - Helpers.Log(2, $"Connecting to {endpoint}..."); - TcpClient tcpClient = null; - try + IPEndPoint endpoint = null; + byte[] preamble, secret = null; + int dcId = _dcSession?.DcID ?? 0; + if (dcId == 0) dcId = 2; + if (MTProxyUrl != null) { +#if OBFUSCATION + if (!IsMainDC) dcId = -dcId; + var parms = HttpUtility.ParseQueryString(MTProxyUrl[MTProxyUrl.IndexOf('?')..]); + var server = parms["server"]; + int port = int.Parse(parms["port"]); + var str = parms["secret"]; // can be hex or base64 + secret = str.All("0123456789ABCDEFabcdef".Contains) ? Convert.FromHexString(str) : + System.Convert.FromBase64String(str.Replace('_', '/').Replace('-', '+') + new string('=', (2147483644 - str.Length) % 4)); + if ((secret.Length == 17 && secret[0] == 0xDD) || (secret.Length >= 21 && secret[0] == 0xEE)) + { + _paddedMode = true; + secret = secret[1..17]; + } + else if (secret.Length != 16) throw new ArgumentException("Invalid/unsupported secret", nameof(secret)); + Helpers.Log(2, $"Connecting to DC {dcId} via MTProxy {server}:{port}..."); + _tcpClient = await TcpHandler(server, port); +#else + throw new Exception("Library was not compiled with OBFUSCATION symbol"); +#endif + } + else + { + endpoint = _dcSession?.EndPoint ?? Compat.IPEndPoint_Parse(Config("server_address")); + Helpers.Log(2, $"Connecting to {endpoint}..."); + TcpClient tcpClient = null; try { - tcpClient = await TcpHandler(endpoint.Address.ToString(), endpoint.Port); - } - catch (SocketException ex) // cannot connect to target endpoint, try to find an alternate - { - Helpers.Log(4, $"SocketException {ex.SocketErrorCode} ({ex.ErrorCode}): {ex.Message}"); - if (_dcSession?.DataCenter == null) throw; - var triedEndpoints = new HashSet { endpoint }; - if (_session.DcOptions != null) + try { - var altOptions = _session.DcOptions.Where(dco => dco.id == _dcSession.DataCenter.id && dco.flags != _dcSession.DataCenter.flags - && (dco.flags & (DcOption.Flags.cdn | DcOption.Flags.tcpo_only | DcOption.Flags.media_only)) == 0) - .OrderBy(dco => dco.flags); - // try alternate addresses for this DC - foreach (var dcOption in altOptions) - { - endpoint = new(IPAddress.Parse(dcOption.ip_address), dcOption.port); - if (!triedEndpoints.Add(endpoint)) continue; - Helpers.Log(2, $"Connecting to {endpoint}..."); - try - { - tcpClient = await TcpHandler(endpoint.Address.ToString(), endpoint.Port); - _dcSession.DataCenter = dcOption; - break; - } - catch (SocketException) { } - } - } - if (tcpClient == null) - { - endpoint = Compat.IPEndPoint_Parse(Config("server_address")); // re-ask callback for an address - if (!triedEndpoints.Add(endpoint)) throw; - _dcSession.Client = null; - // is it address for a known DCSession? - _dcSession = _session.DCSessions.Values.FirstOrDefault(dcs => dcs.EndPoint.Equals(endpoint)); - _dcSession ??= new() { Id = Helpers.RandomLong() }; - _dcSession.Client = this; - Helpers.Log(2, $"Connecting to {endpoint}..."); tcpClient = await TcpHandler(endpoint.Address.ToString(), endpoint.Port); } + catch (SocketException ex) // cannot connect to target endpoint, try to find an alternate + { + Helpers.Log(4, $"SocketException {ex.SocketErrorCode} ({ex.ErrorCode}): {ex.Message}"); + if (_dcSession?.DataCenter == null) throw; + var triedEndpoints = new HashSet { endpoint }; + if (_session.DcOptions != null) + { + var altOptions = _session.DcOptions.Where(dco => dco.id == _dcSession.DataCenter.id && dco.flags != _dcSession.DataCenter.flags + && (dco.flags & (DcOption.Flags.cdn | DcOption.Flags.tcpo_only | DcOption.Flags.media_only)) == 0) + .OrderBy(dco => dco.flags); + // try alternate addresses for this DC + foreach (var dcOption in altOptions) + { + endpoint = new(IPAddress.Parse(dcOption.ip_address), dcOption.port); + if (!triedEndpoints.Add(endpoint)) continue; + Helpers.Log(2, $"Connecting to {endpoint}..."); + try + { + tcpClient = await TcpHandler(endpoint.Address.ToString(), endpoint.Port); + _dcSession.DataCenter = dcOption; + break; + } + catch (SocketException) { } + } + } + if (tcpClient == null) + { + endpoint = Compat.IPEndPoint_Parse(Config("server_address")); // re-ask callback for an address + if (!triedEndpoints.Add(endpoint)) throw; + _dcSession.Client = null; + // is it address for a known DCSession? + _dcSession = _session.DCSessions.Values.FirstOrDefault(dcs => dcs.EndPoint.Equals(endpoint)); + _dcSession ??= new() { Id = Helpers.RandomLong() }; + _dcSession.Client = this; + Helpers.Log(2, $"Connecting to {endpoint}..."); + tcpClient = await TcpHandler(endpoint.Address.ToString(), endpoint.Port); + } + } } + catch (Exception) + { + tcpClient?.Dispose(); + throw; + } + _tcpClient = tcpClient; } - catch (Exception) - { - tcpClient?.Dispose(); - throw; - } - _tcpClient = tcpClient; - _networkStream = tcpClient.GetStream(); - await _networkStream.WriteAsync(IntermediateHeader, 0, 4); + _networkStream = _tcpClient.GetStream(); + + byte protocolId = (byte)(_paddedMode ? 0xDD : 0xEE); +#if OBFUSCATION + (_sendCtr, _recvCtr, preamble) = InitObfuscation(secret, protocolId, dcId); +#else + preamble = new byte[] { protocolId, protocolId, protocolId, protocolId }; +#endif + await _networkStream.WriteAsync(preamble, 0, preamble.Length); + _cts = new(); _saltChangeCounter = 0; _reactorTask = Reactor(_networkStream, _cts); @@ -294,8 +344,8 @@ namespace WTelegram if (_dcSession.DataCenter == null) { _dcSession.DataCenter = _session.DcOptions.Where(dc => dc.id == TLConfig.this_dc) - .OrderByDescending(dc => dc.ip_address == endpoint.Address.ToString()) - .ThenByDescending(dc => dc.port == endpoint.Port).First(); + .OrderByDescending(dc => dc.ip_address == endpoint?.Address.ToString()) + .ThenByDescending(dc => dc.port == endpoint?.Port).First(); _session.DCSessions[TLConfig.this_dc] = _dcSession; } if (_session.MainDC == 0) _session.MainDC = TLConfig.this_dc; @@ -406,6 +456,9 @@ namespace WTelegram { if (await FullReadAsync(stream, data, 4, cts.Token) != 4) throw new ApplicationException(ConnectionShutDown); +#if OBFUSCATION + _recvCtr.EncryptDecrypt(data, 4); +#endif int payloadLen = BinaryPrimitives.ReadInt32LittleEndian(data); if (payloadLen > data.Length) data = new byte[payloadLen]; @@ -413,7 +466,9 @@ namespace WTelegram data = new byte[Math.Max(payloadLen, MinBufferSize)]; if (await FullReadAsync(stream, data, payloadLen, cts.Token) != payloadLen) throw new ApplicationException("Could not read frame data : Connection shut down"); - +#if OBFUSCATION + _recvCtr.EncryptDecrypt(data, payloadLen); +#endif obj = ReadFrame(data, payloadLen); } catch (Exception ex) // an exception in RecvAsync is always fatal @@ -492,7 +547,9 @@ namespace WTelegram long msgId = _lastRecvMsgId = reader.ReadInt64(); if ((msgId & 1) == 0) throw new ApplicationException($"Invalid server msgId {msgId}"); int length = reader.ReadInt32(); - if (length != dataLen - 20) throw new ApplicationException($"Unexpected unencrypted length {length} != {dataLen - 20}"); + dataLen -= 20; + if (length > dataLen || length < dataLen - (_paddedMode ? 15 : 0)) + throw new ApplicationException($"Unexpected unencrypted length {length} != {dataLen}"); var obj = reader.ReadTLObject(); Helpers.Log(1, $"{_dcSession.DcID}>Receiving {obj.GetType().Name,-40} {MsgIdToStamp(msgId):u} clear{((msgId & 2) == 0 ? "" : " NAR")}"); @@ -503,7 +560,7 @@ namespace WTelegram #if MTPROTO1 byte[] decrypted_data = EncryptDecryptMessage(data.AsSpan(24, dataLen - 24), false, _dcSession.AuthKey, data, 8, _sha1Recv); #else - byte[] decrypted_data = EncryptDecryptMessage(data.AsSpan(24, dataLen - 24), false, _dcSession.AuthKey, data, 8, _sha256Recv); + byte[] decrypted_data = EncryptDecryptMessage(data.AsSpan(24, (dataLen - 24) & ~0xF), false, _dcSession.AuthKey, data, 8, _sha256Recv); #endif if (decrypted_data.Length < 36) // header below+ctorNb throw new ApplicationException($"Decrypted packet too small: {decrypted_data.Length}"); @@ -537,7 +594,7 @@ namespace WTelegram _sha256Recv.TransformBlock(_dcSession.AuthKey, 96, 32, null, 0); _sha256Recv.TransformFinalBlock(decrypted_data, 0, decrypted_data.Length); if (!data.AsSpan(8, 16).SequenceEqual(_sha256Recv.Hash.AsSpan(8, 16))) - throw new ApplicationException($"Mismatch between MsgKey & decrypted SHA1"); + throw new ApplicationException($"Mismatch between MsgKey & decrypted SHA256"); _sha256Recv.Initialize(); #endif var ctorNb = reader.ReadUInt32(); @@ -652,12 +709,19 @@ namespace WTelegram writer.Write(msgKeyLarge, msgKeyOffset, 16); // int128 msg_key writer.Write(encrypted_data); // bytes encrypted_data } + if (_paddedMode) // Padded intermediate mode => append random padding + { + var padding = new byte[_random.Next(16)]; + RNG.GetBytes(padding); + writer.Write(padding); + } var buffer = memStream.GetBuffer(); int frameLength = (int)memStream.Length; BinaryPrimitives.WriteInt32LittleEndian(buffer, frameLength - 4); // patch payload_len with correct value - //TODO: support Transport obfuscation? - - await _networkStream.WriteAsync(memStream.GetBuffer(), 0, frameLength); +#if OBFUSCATION + _sendCtr.EncryptDecrypt(buffer, frameLength); +#endif + await _networkStream.WriteAsync(buffer, 0, frameLength); _lastSentMsg = msg; } finally diff --git a/src/Encryption.cs b/src/Encryption.cs index d115b4f..e74c98e 100644 --- a/src/Encryption.cs +++ b/src/Encryption.cs @@ -362,6 +362,79 @@ j4WcDuXc2CTHgH8gFTNhp/Y8/SpDOhvn9QIDAQAB return output; } +#if OBFUSCATION + internal class AesCtr : IDisposable + { + readonly ICryptoTransform encryptor; + readonly byte[] ivec; + byte[] ecount; + int num; + + public AesCtr(Aes aes, byte[] key, byte[] iv) + { + encryptor = aes.CreateEncryptor(key, null); + ivec = iv; + } + + public void Dispose() => encryptor.Dispose(); + + public void EncryptDecrypt(byte[] buffer, int length) + { + for (int i = 0; i < length; i++) + { + if (num == 0) + { + ecount = encryptor.TransformFinalBlock(ivec, 0, 16); + for (int n = 15; n >= 0; n--) // increment big-endian counter + if (++ivec[n] != 0) break; + } + buffer[i] ^= ecount[num]; + num = (num + 1) % 16; + } + } + } + + // see https://core.telegram.org/mtproto/mtproto-transports#transport-obfuscation + internal static (AesCtr, AesCtr, byte[]) InitObfuscation(byte[] secret, byte protocolId, int dcId) + { + byte[] preamble = new byte[64]; + do + RNG.GetBytes(preamble, 0, 58); + while (preamble[0] == 0xef || + BinaryPrimitives.ReadUInt32LittleEndian(preamble) is 0x44414548 or 0x54534f50 or 0x20544547 or 0x4954504f or 0x02010316 or 0xdddddddd or 0xeeeeeeee || + BinaryPrimitives.ReadInt32LittleEndian(preamble.AsSpan(4)) == 0); + preamble[62] = preamble[56]; preamble[63] = preamble[57]; + preamble[56] = preamble[57] = preamble[58] = preamble[59] = protocolId; + preamble[60] = (byte)dcId; preamble[61] = (byte)(dcId >> 8); + + byte[] recvKey = preamble[8..40], recvIV = preamble[40..56]; + Array.Reverse(preamble, 8, 48); + byte[] sendKey = preamble[8..40], sendIV = preamble[40..56]; + if (secret != null) + { + using var sha256 = SHA256.Create(); + sha256.TransformBlock(sendKey, 0, 32, null, 0); + sha256.TransformFinalBlock(secret, 0, 16); + sendKey = sha256.Hash; + sha256.Initialize(); + sha256.TransformBlock(recvKey, 0, 32, null, 0); + sha256.TransformFinalBlock(secret, 0, 16); + recvKey = sha256.Hash; + } + using var aes = Aes.Create(); + aes.Mode = CipherMode.ECB; + aes.Padding = PaddingMode.None; + if (aes.BlockSize != 128) throw new ApplicationException("AES Blocksize is not 16 bytes"); + var sendCtr = new AesCtr(aes, sendKey, sendIV); + var recvCtr = new AesCtr(aes, recvKey, recvIV); + var encrypted = (byte[])preamble.Clone(); + sendCtr.EncryptDecrypt(encrypted, 64); + for (int i = 56; i < 64; i++) + preamble[i] = encrypted[i]; + return (sendCtr, recvCtr, preamble); + } +#endif + internal static async Task Check2FA(Account_Password accountPassword, Func> getPassword) { bool newPassword = false; diff --git a/src/WTelegramClient.csproj b/src/WTelegramClient.csproj index 6932929..f94f315 100644 --- a/src/WTelegramClient.csproj +++ b/src/WTelegramClient.csproj @@ -24,6 +24,7 @@ Telegram;Client;Api;UserBot;MTProto;TLSharp;OpenTl README.md IDE0079;0419;1573;1591 + TRACE;OBFUSCATION