mirror of
https://github.com/wiz0u/WTelegramClient.git
synced 2025-12-06 06:52:01 +01:00
162 lines
7.2 KiB
C#
162 lines
7.2 KiB
C#
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using System;
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using System.Buffers.Binary;
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using System.IO;
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using System.Linq;
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using System.Security.Cryptography;
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using System.Threading;
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using System.Threading.Tasks;
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// necessary for .NET Standard 2.0 compilation:
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#pragma warning disable CA1835 // Prefer the 'Memory'-based overloads for 'ReadAsync' and 'WriteAsync'
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namespace WTelegram
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{
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class TlsStream : Stream
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{
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public TlsStream(Stream innerStream) => _innerStream = innerStream;
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private readonly Stream _innerStream;
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private int _tlsFrameleft;
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private readonly byte[] _tlsSendHeader = new byte[] { 0x17, 0x03, 0x03, 0, 0 };
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private readonly byte[] _tlsReadHeader = new byte[5];
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static readonly byte[] TlsServerHelloPart3 = new byte[] { 0x14, 0x03, 0x03, 0x00, 0x01, 0x01, 0x17, 0x03, 0x03 };
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static readonly byte[] TlsClientPrefix = new byte[] { 0x14, 0x03, 0x03, 0x00, 0x01, 0x01 };
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public override bool CanRead => true;
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public override bool CanSeek => false;
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public override bool CanWrite => true;
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public override long Length => throw new NotSupportedException();
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public override long Position { get => throw new NotSupportedException(); set => throw new NotSupportedException(); }
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public override void Flush() => _innerStream.Flush();
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public override int Read(byte[] buffer, int offset, int count) => throw new NotSupportedException();
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public override long Seek(long offset, SeekOrigin origin) => throw new NotSupportedException();
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public override void SetLength(long value) => throw new NotSupportedException();
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public override void Write(byte[] buffer, int offset, int count) => throw new NotSupportedException();
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public override async Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken ct)
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{
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if (_tlsFrameleft == 0)
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{
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if (await _innerStream.FullReadAsync(_tlsReadHeader, 5, ct) != 5)
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return 0;
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if (_tlsReadHeader[0] != 0x17 || _tlsReadHeader[1] != 0x03 || _tlsReadHeader[2] != 0x03)
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throw new ApplicationException("Could not read frame data : Invalid TLS header");
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_tlsFrameleft = (_tlsReadHeader[3] << 8) + _tlsReadHeader[4];
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}
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var read = await _innerStream.ReadAsync(buffer, offset, Math.Min(count, _tlsFrameleft), ct);
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_tlsFrameleft -= read;
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return read;
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}
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public override async Task WriteAsync(byte[] buffer, int start, int count, CancellationToken ct)
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{
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for (int offset = 0; offset < count;)
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{
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int len = Math.Min(count - offset, 2878);
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_tlsSendHeader[3] = (byte)(len >> 8);
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_tlsSendHeader[4] = (byte)len;
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await _innerStream.WriteAsync(_tlsSendHeader, 0, _tlsSendHeader.Length, ct);
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await _innerStream.WriteAsync(buffer, start + offset, len, ct);
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offset += len;
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}
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}
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public static async Task<TlsStream> HandshakeAsync(Stream stream, byte[] key, byte[] domain, CancellationToken ct)
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{
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var clientHello = TlsClientHello(key, domain);
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await stream.WriteAsync(clientHello, 0, clientHello.Length, ct);
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var part1 = new byte[5];
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if (await stream.FullReadAsync(part1, 5, ct) == 5)
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if (part1[0] == 0x16 && part1[1] == 0x03 && part1[2] == 0x03)
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{
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var part2size = BinaryPrimitives.ReadUInt16BigEndian(part1.AsSpan(3));
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var part23 = new byte[part2size + TlsServerHelloPart3.Length + 2];
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if (await stream.FullReadAsync(part23, part23.Length, ct) == part23.Length)
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if (TlsServerHelloPart3.SequenceEqual(part23.Skip(part2size).Take(TlsServerHelloPart3.Length)))
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{
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var part4size = BinaryPrimitives.ReadUInt16BigEndian(part23.AsSpan(part23.Length - 2));
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var part4 = new byte[part4size];
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if (await stream.FullReadAsync(part4, part4size, ct) == part4size)
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{
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var serverDigest = part23[6..38];
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Array.Clear(part23, 6, 32); // clear server digest from received parts
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var hmc = new HMACSHA256(key); // hash the client digest + all received parts
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hmc.TransformBlock(clientHello, 11, 32, null, 0);
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hmc.TransformBlock(part1, 0, part1.Length, null, 0);
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hmc.TransformBlock(part23, 0, part23.Length, null, 0);
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hmc.TransformFinalBlock(part4, 0, part4.Length);
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if (serverDigest.SequenceEqual(hmc.Hash))
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{
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Helpers.Log(2, "TLS Handshake succeeded");
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await stream.WriteAsync(TlsClientPrefix, 0, TlsClientPrefix.Length, ct);
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return new TlsStream(stream);
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}
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}
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}
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}
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throw new ApplicationException("TLS Handshake failed");
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}
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static readonly byte[] TlsClientHello1 = new byte[] {
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0x16, 0x03, 0x01, 0x02, 0x00, 0x01, 0x00, 0x01, 0xfc, 0x03, 0x03 };
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static readonly byte[] TlsClientHello2 = new byte[] {
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0x13, 0x01, 0x13, 0x02, 0x13, 0x03, 0xc0, 0x2b, 0xc0, 0x2f, 0xc0, 0x2c, 0xc0, 0x30, 0xcc, 0xa9,
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0xcc, 0xa8, 0xc0, 0x13, 0xc0, 0x14, 0x00, 0x9c, 0x00, 0x9d, 0x00, 0x2f, 0x00, 0x35, 0x01, 0x00, 0x01, 0x93 };
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static readonly byte[] TlsClientHello3 = new byte[] {
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0x00, 0x17, 0x00, 0x00, 0xff, 0x01, 0x00, 0x01, 0x00, 0x00, 0x0a, 0x00, 0x0a, 0x00, 0x08,
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0, 0, // grease 4
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0x00, 0x1d, 0x00, 0x17, 0x00, 0x18, 0x00, 0x0b, 0x00, 0x02, 0x01, 0x00, 0x00, 0x23, 0x00, 0x00,
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0x00, 0x10, 0x00, 0x0e, 0x00, 0x0c, 0x02, 0x68, 0x32, 0x08, 0x68, 0x74, 0x74, 0x70, 0x2f, 0x31,
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0x2e, 0x31, 0x00, 0x05, 0x00, 0x05, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0d, 0x00, 0x12, 0x00,
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0x10, 0x04, 0x03, 0x08, 0x04, 0x04, 0x01, 0x05, 0x03, 0x08, 0x05, 0x05, 0x01, 0x08, 0x06, 0x06,
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0x01, 0x00, 0x12, 0x00, 0x00, 0x00, 0x33, 0x00, 0x2b, 0x00, 0x29,
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0, 0, // grease 4
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0x00, 0x01, 0x00, 0x00, 0x1d, 0x00, 0x20 };
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static readonly byte[] TlsClientHello4 = new byte[] {
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0x00, 0x2d, 0x00, 0x02, 0x01, 0x01, 0x00, 0x2b, 0x00, 0x0b, 0x0a,
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0, 0, // grease 6
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0x03, 0x04, 0x03, 0x03, 0x03, 0x02, 0x03, 0x01, 0x00, 0x1b, 0x00, 0x03, 0x02, 0x00, 0x02,
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0, 0, // grease 3
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0x00, 0x01, 0x00, 0x00, 0x15 };
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static byte[] TlsClientHello(byte[] key, byte[] domain)
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{
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int dlen = domain.Length;
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var greases = new byte[7];
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Encryption.RNG.GetBytes(greases);
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for (int i = 0; i < 7; i++) greases[i] = (byte)((greases[i] & 0xF0) + 0x0A);
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if (greases[3] == greases[2]) greases[3] = (byte)(0x10 ^ greases[3]);
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var buffer = new byte[517];
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TlsClientHello1.CopyTo(buffer, 0);
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TlsClientHello2.CopyTo(buffer, 80);
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buffer[43] = buffer[77] = 0x20;
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Encryption.RNG.GetBytes(buffer, 44, 32);
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buffer[78] = buffer[79] = greases[0];
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buffer[114] = buffer[115] = greases[2];
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buffer[121] = (byte)(dlen + 5);
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buffer[123] = (byte)(dlen + 3);
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buffer[126] = (byte)dlen;
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domain.CopyTo(buffer, 127);
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TlsClientHello3.CopyTo(buffer, 127 + dlen);
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buffer[142 + dlen] = buffer[143 + dlen] = greases[4];
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buffer[219 + dlen] = buffer[220 + dlen] = greases[4];
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Encryption.RNG.GetBytes(buffer, 228 + dlen, 32); // public key
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TlsClientHello4.CopyTo(buffer, 260 + dlen);
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buffer[271 + dlen] = buffer[272 + dlen] = greases[6];
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buffer[288 + dlen] = buffer[289 + dlen] = greases[3];
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buffer[296 + dlen] = (byte)(220 - dlen);
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// patch-in digest with timestamp
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using var hmac = new HMACSHA256(key);
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var digest = hmac.ComputeHash(buffer);
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var stamp = BinaryPrimitives.ReadInt32LittleEndian(digest.AsSpan(28));
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stamp ^= (int)DateTimeOffset.UtcNow.ToUnixTimeSeconds();
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BinaryPrimitives.WriteInt32LittleEndian(digest.AsSpan(28), stamp);
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digest.CopyTo(buffer, 11);
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return buffer;
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}
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}
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}
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