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TlsClientStream.cs
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#if NET45 || NET451 || DNX451
#region License
// The PostgreSQL License
//
// Copyright (C) 2016 The Npgsql Development Team
//
// Permission to use, copy, modify, and distribute this software and its
// documentation for any purpose, without fee, and without a written
// agreement is hereby granted, provided that the above copyright notice
// and this paragraph and the following two paragraphs appear in all copies.
//
// IN NO EVENT SHALL THE NPGSQL DEVELOPMENT TEAM BE LIABLE TO ANY PARTY
// FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES,
// INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
// DOCUMENTATION, EVEN IF THE NPGSQL DEVELOPMENT TEAM HAS BEEN ADVISED OF
// THE POSSIBILITY OF SUCH DAMAGE.
//
// THE NPGSQL DEVELOPMENT TEAM SPECIFICALLY DISCLAIMS ANY WARRANTIES,
// INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
// AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
// ON AN "AS IS" BASIS, AND THE NPGSQL DEVELOPMENT TEAM HAS NO OBLIGATIONS
// TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
#endregion
#undef CHECK_ARGUMENTS
//using AsyncRewriter;
using System;
using System.Collections.Generic;
using System.Diagnostics.Contracts;
using System.IO;
using System.Linq;
using System.Net.Sockets;
using System.Numerics;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
namespace TlsClientStream
{
internal partial class TlsClientStream : Stream
{
const TlsVersion HighestTlsVersionSupported = TlsVersion.TLSv1_2;
const int MaxEncryptedRecordLen = (1 << 14) /* data */ + 16 + 64 + 256 /* iv + mac + padding (accept long CBC mode padding) */;
// Buffer data
byte[] _buf = new byte[5 /* header */ + MaxEncryptedRecordLen];
int _readStart;
int _readEnd;
int _packetLen;
Stream _baseStream;
// Connection states
// Read connection state is for the purpose when we have sent ChangeCipherSpec but the server hasn't yet
ConnectionState _connState;
ConnectionState _readConnState;
ConnectionState _pendingConnState;
RNGCryptoServiceProvider _rng = new RNGCryptoServiceProvider();
// Info about the current message in the buffer
ContentType _contentType;
int _plaintextLen;
int _plaintextStart;
// Temp buffer to hold sequence number
byte[] _tempBuf8 = new byte[8];
// Temp buffer for GCM
byte[] _temp512;
// Holds buffered handshake messages that will be dequeued as soon as a proper final message has been received (ServerHelloDone or Finished)
HandshakeMessagesBuffer _handshakeMessagesBuffer = new HandshakeMessagesBuffer();
HandshakeData _handshakeData;
// User parameters
bool _noRenegotiationExtensionSupportIsFatal = false;
string _hostName = null;
X509CertificateCollection _clientCertificates;
System.Net.Security.RemoteCertificateValidationCallback _remoteCertificationValidationCallback;
bool _checkCertificateRevocation;
bool _waitingForChangeCipherSpec;
bool _waitingForFinished;
// When renegotiating we use another buffer to avoid overwriting the normal one
byte[] _renegotiationTempWriteBuf;
// Used in Read and Write methods to keep track of position
int _writePos;
int _decryptedReadPos;
int _decryptedReadEnd;
// When we write in the middle of a handshake, we must block until the handshake is completed before
// we can actually write the data, due to a bug in OpenSSL. If we at the same time receive data from
// the server, we must buffer it so it can be delivered to the application later.
// Note that this is quite uncommon, since one normally drains the read buffer before writing.
const int MaxBufferedReadData = 10 * (1 << 20); // 10 MB
Queue<byte[]> _bufferedReadData;
int _posBufferedReadData;
int _lenBufferedReadData;
// Stream state
bool _eof;
bool _closed;
/// <summary>
/// Creates a new TlsClientStream with the given underlying stream.
/// The handshake must be manually initiated with the method PerformInitialHandshake.
/// </summary>
/// <param name="baseStream">Base stream</param>
public TlsClientStream(Stream baseStream)
{
_connState = new ConnectionState() { TlsVersion = TlsVersion.TLSv1_0 };
_readConnState = _connState;
_baseStream = baseStream;
}
#region Record layer
/// <summary>
/// Makes sure there is at least one full record available at _readStart.
/// Also sets _packetLen (does not include packet header of 5 bytes).
/// </summary>
/// <returns>True on success, false on End Of Stream.</returns>
//[RewriteAsync]
bool ReadRecord()
{
int packetLength = -1;
while (true)
{
if (packetLength == -1 && _readEnd - _readStart >= 5)
{
// We have at least a header in our buffer, so extract the length
packetLength = (_buf[_readStart + 3] << 8) | _buf[_readStart + 4];
if (packetLength > MaxEncryptedRecordLen)
{
SendAlertFatal(AlertDescription.RecordOverflow);
}
}
if (packetLength != -1 && 5 + packetLength <= _readEnd - _readStart)
{
// The whole record fits in the buffer. We are done.
_packetLen = packetLength;
return true;
}
if (_readEnd - _readStart > 0 && _readStart > 0)
{
// We only have a partial record in the buffer,
// move that to the beginning to be able to read as much as possible from the network.
Buffer.BlockCopy(_buf, _readStart, _buf, 0, _readEnd - _readStart);
_readEnd -= _readStart;
_readStart = 0;
}
if (packetLength == -1 || _readEnd < 5 + packetLength)
{
if (_readStart == _readEnd)
{
// The read buffer is empty, so start reading at the start of the buffer
_readStart = 0;
_readEnd = 0;
}
int read = _baseStream.Read(_buf, _readEnd, _buf.Length - _readEnd);
if (read == 0)
{
return false;
}
_readEnd += read;
}
}
}
// ReadRecord should be called first.
// Sets _contentType, _plaintextStart and _plaintextLength, and increments _readStart
void Decrypt()
{
_contentType = (ContentType)_buf[_readStart];
if (_readConnState.CipherSuite == null)
{
_plaintextStart = _readStart + 5;
_plaintextLen = _packetLen;
}
else if (_readConnState.CipherSuite.AesMode == AesMode.CBC)
{
var minPlaintextBytes = _readConnState.MacLen + 1;
var minEncryptedBlocks = (minPlaintextBytes + _readConnState.BlockLen - 1) / _readConnState.BlockLen;
var minEncryptedBytes = minEncryptedBlocks * _readConnState.BlockLen;
if (_packetLen < _readConnState.IvLen + minEncryptedBytes || (_packetLen - _readConnState.IvLen) % _readConnState.BlockLen != 0)
SendAlertFatal(AlertDescription.BadRecordMac);
Buffer.BlockCopy(_buf, _readStart + 5, _readConnState.ReadIv, 0, _readConnState.IvLen);
_readConnState.ReadAes.IV = _readConnState.ReadIv;
int cipherStartPos = _readStart + 5 + _readConnState.IvLen;
int cipherLen = _packetLen - _readConnState.IvLen;
if (_readConnState.TlsVersion == TlsVersion.TLSv1_0)
{
// Save the last ciphertext block to become the IV for the next record
Buffer.BlockCopy(_buf, cipherStartPos + cipherLen - _readConnState.BlockLen, _readConnState.ReadIv, 0, _readConnState.BlockLen);
}
using (var decryptor = _readConnState.ReadAes.CreateDecryptor())
{
decryptor.TransformBlock(_buf, cipherStartPos, cipherLen, _buf, cipherStartPos);
}
int paddingLen = _buf[cipherStartPos + cipherLen - 1];
bool paddingFail = false;
if (paddingLen > cipherLen - 1 - _readConnState.MacLen)
{
// We have found illegal padding. Instead of just send fatal alert directly,
// still do the mac computation and let it fail to deal with timing attacks.
paddingLen = 0;
paddingFail = true;
}
int plaintextLen = cipherLen - 1 - paddingLen - _readConnState.MacLen;
// We don't need the IV anymore in the buffer, so overwrite it with seq_num + header to calculate MAC
/*Buffer.BlockCopy(_buf, _readStart, _buf, cipherStartPos - 5, 3);
Utils.WriteUInt16(_buf, cipherStartPos - 2, (ushort)plaintextLen);
Utils.WriteUInt64(_buf, cipherStartPos - 5 - 8, _readConnState.ReadSeqNum);*/
// We should use the plaintext len, not the encrypted len for the MAC
_readConnState.ReadMac.Initialize();
Utils.WriteUInt64(_tempBuf8, 0, _readConnState.ReadSeqNum);
_readConnState.ReadMac.TransformBlock(_tempBuf8, 0, 8);
Utils.WriteUInt16(_buf, _readStart + 3, (ushort)plaintextLen);
_readConnState.ReadMac.TransformBlock(_buf, _readStart, 5);
_readConnState.ReadMac.TransformBlock(_buf, cipherStartPos, plaintextLen);
_readConnState.ReadMac.TransformFinalBlock(_tempBuf8, 0, 0);
var hmac = _readConnState.ReadMac.Hash;
if (!Utils.ArraysEqual(hmac, 0, _buf, cipherStartPos + plaintextLen, hmac.Length))
SendAlertFatal(AlertDescription.BadRecordMac);
// Verify that the padding bytes contain the correct value (paddingLen)
for (int i = 0; i < paddingLen; i++)
if (_buf[cipherStartPos + cipherLen - 2 - i] != paddingLen)
SendAlertFatal(AlertDescription.BadRecordMac);
// Very unlikely MAC didn't catch this
if (paddingFail)
SendAlertFatal(AlertDescription.BadRecordMac);
_plaintextStart = cipherStartPos;
_plaintextLen = plaintextLen;
}
else if (_readConnState.CipherSuite.AesMode == AesMode.GCM)
{
Buffer.BlockCopy(_buf, _readStart + 5, _readConnState.ReadIv, 4, _readConnState.IvLen);
var cipherStartPos = _readStart + 5 + _readConnState.IvLen;
var plaintextLen = _packetLen - 16 - _readConnState.IvLen;
if (plaintextLen < 0)
SendAlertFatal(AlertDescription.BadRecordMac);
var ok = GaloisCounterMode.GCMAD(_readConnState.ReadAesECB, _readConnState.ReadIv, _buf, cipherStartPos, plaintextLen, _readConnState.ReadSeqNum, (byte)_contentType, _readConnState.ReadGCMTable, _temp512);
if (!ok)
SendAlertFatal(AlertDescription.BadRecordMac);
_plaintextStart = cipherStartPos;
_plaintextLen = plaintextLen;
}
_readStart += 5 + _packetLen;
_readConnState.ReadSeqNum++;
}
// startPos: at content type, len: plaintext length without header
// updates seq num
/// <summary>
/// Encrypts a record.
/// A header should be at startPos containing TLS record type and version.
/// At startPos + 5 + ivLen the plaintext should start.
/// </summary>
/// <param name="startPos">Should point to the beginning of the record (content type)</param>
/// <param name="len">Plaintext length (without header)</param>
/// <returns>The byte position after the last byte in this encrypted record</returns>
int Encrypt(int startPos, int len)
{
if (_connState.CipherSuite != null && _connState.CipherSuite.AesMode == AesMode.CBC)
{
// Update length first with plaintext length
Utils.WriteUInt16(_buf, startPos + 3, (ushort)len);
Utils.WriteUInt64(_tempBuf8, 0, _connState.WriteSeqNum++);
_connState.WriteMac.Initialize();
_connState.WriteMac.TransformBlock(_tempBuf8, 0, 8);
_connState.WriteMac.TransformBlock(_buf, startPos, 5);
_connState.WriteMac.TransformBlock(_buf, startPos + 5 + _connState.IvLen, len);
_connState.WriteMac.TransformFinalBlock(_buf, 0, 0);
var mac = _connState.WriteMac.Hash;
Buffer.BlockCopy(mac, 0, _buf, startPos + 5 + _connState.IvLen + len, mac.Length);
Utils.ClearArray(mac);
var paddingLen = _connState.BlockLen - (len + _connState.MacLen + 1) % _connState.BlockLen;
for (var i = 0; i < paddingLen + 1; i++)
_buf[startPos + 5 + _connState.IvLen + len + _connState.MacLen + i] = (byte)paddingLen;
int encryptedLen = len + _connState.MacLen + paddingLen + 1;
// Update length now with encrypted length
Utils.WriteUInt16(_buf, startPos + 3, (ushort)(_connState.IvLen + encryptedLen));
if (_connState.TlsVersion != TlsVersion.TLSv1_0)
{
_rng.GetBytes(_connState.WriteIv);
Buffer.BlockCopy(_connState.WriteIv, 0, _buf, startPos + 5, _connState.WriteIv.Length);
}
_connState.WriteAes.IV = _connState.WriteIv;
using (var encryptor = _connState.WriteAes.CreateEncryptor())
{
encryptor.TransformBlock(_buf, startPos + 5 + _connState.IvLen, encryptedLen, _buf, startPos + 5 + _connState.IvLen);
}
if (_connState.TlsVersion == TlsVersion.TLSv1_0)
{
// Save last ciphertext block as the next IV
Buffer.BlockCopy(_buf, startPos + 5 + encryptedLen - _connState.BlockLen, _connState.WriteIv, 0, _connState.BlockLen);
}
return startPos + 5 + _connState.IvLen + encryptedLen;
}
else if (_connState.CipherSuite != null && _connState.CipherSuite.AesMode == AesMode.GCM)
{
Utils.WriteUInt64(_connState.WriteIv, 4, _connState.WriteSeqNum);
Utils.WriteUInt64(_buf, startPos + 5, _connState.WriteSeqNum);
GaloisCounterMode.GCMAE(_connState.WriteAesECB, _connState.WriteIv, _buf, startPos + 5 + _connState.IvLen, len, _connState.WriteSeqNum++, _buf[startPos], _connState.WriteGCMTable, _temp512);
Utils.WriteUInt16(_buf, startPos + 3, (ushort)(_connState.IvLen + len + 16));
return startPos + 5 + _connState.IvLen + len + 16;
}
else // Null cipher
{
// Update length
Utils.WriteUInt16(_buf, startPos + 3, (ushort)len);
return startPos + 5 + len;
}
}
#endregion
#region Handshake infrastructure
void UpdateHandshakeHash(byte[] buf, int offset, int len)
{
// .NET hash api does not allow us to clone hash states ...
if (_handshakeData.HandshakeHash1 != null)
_handshakeData.HandshakeHash1.TransformBlock(buf, offset, len);
if (_handshakeData.HandshakeHash1_384 != null)
_handshakeData.HandshakeHash1_384.TransformBlock(buf, offset, len);
if (_handshakeData.HandshakeHash2 != null)
_handshakeData.HandshakeHash2.TransformBlock(buf, offset, len);
if (_handshakeData.HandshakeHash2_384 != null)
_handshakeData.HandshakeHash2_384.TransformBlock(buf, offset, len);
if (_handshakeData.HandshakeHash1_MD5SHA1 != null)
_handshakeData.HandshakeHash1_MD5SHA1.TransformBlock(buf, offset, len);
if (_handshakeData.HandshakeHash2_MD5SHA1 != null)
_handshakeData.HandshakeHash2_MD5SHA1.TransformBlock(buf, offset, len);
if (_handshakeData.CertificateVerifyHash_MD5 != null)
_handshakeData.CertificateVerifyHash_MD5.TransformBlock(buf, offset, len);
if (_handshakeData.CertificateVerifyHash_SHA1 != null)
_handshakeData.CertificateVerifyHash_SHA1.TransformBlock(buf, offset, len);
}
//[RewriteAsync]
void GetInitialHandshakeMessages(bool allowApplicationData = false)
{
while (!_handshakeMessagesBuffer.HasServerHelloDone)
{
if (!ReadRecord())
throw new IOException("Connection EOF in initial handshake");
Decrypt();
switch (_contentType)
{
case ContentType.Alert:
HandleAlertMessage();
break;
case ContentType.Handshake:
_handshakeMessagesBuffer.AddBytes(_buf, _plaintextStart, _plaintextLen, HandshakeMessagesBuffer.IgnoreHelloRequestsSettings.IgnoreHelloRequests);
if (_handshakeMessagesBuffer.Messages.Count > 5)
{
// There can never be more than 5 handshake messages in a handshake
SendAlertFatal(AlertDescription.UnexpectedMessage);
}
break;
case ContentType.ApplicationData:
EnqueueReadData(allowApplicationData);
break;
default:
SendAlertFatal(AlertDescription.UnexpectedMessage);
break;
}
}
var responseLen = TraverseHandshakeMessages();
_baseStream.Write(_buf, 0, responseLen);
_baseStream.Flush();
ResetWritePos();
_waitingForChangeCipherSpec = true;
}
int TraverseHandshakeMessages()
{
HandshakeType lastType = 0;
int responseLen = 0;
for (var i = 0; i < _handshakeMessagesBuffer.Messages.Count; i++)
{
int pos = 0;
var buf = _handshakeMessagesBuffer.Messages[i];
UpdateHandshakeHash(buf, 0, buf.Length);
HandshakeType msgType = (HandshakeType)buf[pos++];
int msgLen = Utils.ReadUInt24(buf, ref pos);
switch (msgType)
{
case HandshakeType.ServerHello:
if (lastType != 0)
SendAlertFatal(AlertDescription.UnexpectedMessage);
ParseServerHelloMessage(buf, ref pos, pos + msgLen);
break;
case HandshakeType.Certificate:
if (lastType != HandshakeType.ServerHello)
SendAlertFatal(AlertDescription.UnexpectedMessage);
ParseCertificateMessage(buf, ref pos);
break;
case HandshakeType.ServerKeyExchange:
if (lastType != HandshakeType.Certificate)
SendAlertFatal(AlertDescription.UnexpectedMessage);
ParseServerKeyExchangeMessage(buf, ref pos);
break;
case HandshakeType.CertificateRequest:
if (lastType != HandshakeType.Certificate && lastType != HandshakeType.ServerKeyExchange)
SendAlertFatal(AlertDescription.UnexpectedMessage);
ParseCertificateRequest(buf, ref pos);
break;
case HandshakeType.ServerHelloDone:
if (msgLen != 0)
SendAlertFatal(AlertDescription.DecodeError);
if ((lastType != HandshakeType.Certificate && lastType != HandshakeType.ServerKeyExchange && lastType != HandshakeType.CertificateRequest)
|| i != _handshakeMessagesBuffer.Messages.Count - 1)
SendAlertFatal(AlertDescription.UnexpectedMessage);
responseLen = GenerateHandshakeResponse();
break;
default:
SendAlertFatal(AlertDescription.UnexpectedMessage);
break;
}
if (pos != 4 + msgLen)
SendAlertFatal(AlertDescription.DecodeError);
lastType = msgType;
}
_handshakeMessagesBuffer.ClearMessages();
return responseLen;
}
// Here we send all client messages in response to server hello
int GenerateHandshakeResponse()
{
int offset = 0;
var ivLen = _connState.IvLen;
if (_handshakeData.CertificateTypes != null) // Certificate request has been sent by the server
{
SendHandshakeMessage(SendClientCertificate, ref offset, ivLen);
}
switch (_pendingConnState.CipherSuite.KeyExchange)
{
case KeyExchange.DHE_RSA:
case KeyExchange.DHE_DSS:
SendHandshakeMessage(SendClientKeyExchangeDhe, ref offset, ivLen);
break;
case KeyExchange.ECDHE_RSA:
case KeyExchange.ECDHE_ECDSA:
SendHandshakeMessage(SendClientKeyExchangeEcdhe, ref offset, ivLen);
break;
case KeyExchange.ECDH_ECDSA:
case KeyExchange.ECDH_RSA:
SendHandshakeMessage(SendClientKeyExchangeEcdh, ref offset, ivLen);
break;
case KeyExchange.RSA:
SendHandshakeMessage(SendClientKeyExchangeRsa, ref offset, ivLen);
break;
default:
throw new InvalidOperationException();
}
if (_handshakeData.CertificateTypes != null && _handshakeData.SelectedClientCertificate != null)
{
SendHandshakeMessage(SendCertificateVerify, ref offset, ivLen);
}
var cipherSpecStart = offset;
SendChangeCipherSpec(ref offset, ivLen);
offset = Encrypt(cipherSpecStart, 1);
// Key generation from Master Secret
var mode = _pendingConnState.CipherSuite.AesMode;
var isCbc = mode == AesMode.CBC;
var isGcm = mode == AesMode.GCM;
var concRandom = new byte[_pendingConnState.ServerRandom.Length + _pendingConnState.ClientRandom.Length];
Buffer.BlockCopy(_pendingConnState.ServerRandom, 0, concRandom, 0, _pendingConnState.ServerRandom.Length);
Buffer.BlockCopy(_pendingConnState.ClientRandom, 0, concRandom, _pendingConnState.ServerRandom.Length, _pendingConnState.ClientRandom.Length);
var macLen = isCbc ? _pendingConnState.CipherSuite.MACLen / 8 : 0;
var aesKeyLen = _pendingConnState.CipherSuite.AesKeyLen / 8;
var IVLen = isGcm ? 4 : _pendingConnState.TlsVersion != TlsVersion.TLSv1_0 ? 0 : _pendingConnState.BlockLen;
var keyBlock = Utils.PRF(_pendingConnState.PRFAlgorithm, _pendingConnState.MasterSecret, "key expansion", concRandom, macLen * 2 + aesKeyLen * 2 + IVLen * 2);
byte[] writeMac = new byte[macLen], readMac = new byte[macLen], writeKey = new byte[aesKeyLen], readKey = new byte[aesKeyLen];
Buffer.BlockCopy(keyBlock, 0, writeMac, 0, macLen);
Buffer.BlockCopy(keyBlock, macLen, readMac, 0, macLen);
Buffer.BlockCopy(keyBlock, macLen * 2, writeKey, 0, aesKeyLen);
Buffer.BlockCopy(keyBlock, macLen * 2 + aesKeyLen, readKey, 0, aesKeyLen);
if (isCbc)
{
_pendingConnState.WriteMac = _pendingConnState.CipherSuite.CreateHMAC(writeMac);
_pendingConnState.ReadMac = _pendingConnState.CipherSuite.CreateHMAC(readMac);
}
if (IVLen != 0)
{
// For GCM we make it bigger to later fill in sequence numbers
var writeIv = new byte[isGcm ? 16 : IVLen];
var readIv = new byte[isGcm ? 16 : IVLen];
Buffer.BlockCopy(keyBlock, macLen * 2 + aesKeyLen * 2, writeIv, 0, IVLen);
Buffer.BlockCopy(keyBlock, macLen * 2 + aesKeyLen * 2 + IVLen, readIv, 0, IVLen);
_pendingConnState.WriteIv = writeIv;
_pendingConnState.ReadIv = readIv;
}
else
{
_pendingConnState.ReadIv = _pendingConnState.WriteIv = new byte[_pendingConnState.BlockLen];
}
_pendingConnState.WriteAes = new AesCryptoServiceProvider() { Key = writeKey, Mode = isCbc ? CipherMode.CBC : CipherMode.ECB, Padding = PaddingMode.None };
_pendingConnState.ReadAes = new AesCryptoServiceProvider() { Key = readKey, Mode = isCbc ? CipherMode.CBC : CipherMode.ECB, Padding = PaddingMode.None };
// int tmpOffset = macLen * 2 + aesKeyLen * 2;
if (isGcm)
{
_pendingConnState.WriteAesECB = _pendingConnState.WriteAes.CreateEncryptor(writeKey, null);
_pendingConnState.ReadAesECB = _pendingConnState.ReadAes.CreateEncryptor(readKey, null);
_pendingConnState.WriteGCMTable = GaloisCounterMode.GetH(_pendingConnState.WriteAesECB);
_pendingConnState.ReadGCMTable = GaloisCounterMode.GetH(_pendingConnState.ReadAesECB);
if (_temp512 == null)
_temp512 = new byte[512];
}
Utils.ClearArray(writeMac);
Utils.ClearArray(readMac);
Utils.ClearArray(writeKey);
Utils.ClearArray(readKey);
ivLen = _pendingConnState.IvLen;
_connState = _pendingConnState;
SendHandshakeMessage(SendFinished, ref offset, ivLen);
_handshakeData.HandshakeHash2.TransformFinalBlock(_buf, 0, 0);
// _buf is now ready to be written to the base stream, from pos 0 to offset
return offset;
}
delegate HandshakeType SendHandshakeMessageDelegate(ref int offset);
void SendHandshakeMessage(SendHandshakeMessageDelegate func, ref int offset, int ivLen)
{
int start = offset;
int messageStart = start + 5 + ivLen;
_buf[offset++] = (byte)ContentType.Handshake;
// Highest version supported
offset += Utils.WriteUInt16(_buf, offset, (ushort)_connState.TlsVersion);
// Record length to be filled in later
offset += 2;
offset += ivLen;
int handshakeTypePos = offset;
// Type and length filled in below
offset += 4;
var handshakeType = func(ref offset);
var messageLen = offset - (handshakeTypePos + 4);
_buf[handshakeTypePos] = (byte)handshakeType;
Utils.WriteUInt24(_buf, handshakeTypePos + 1, messageLen);
UpdateHandshakeHash(_buf, messageStart, offset - messageStart);
offset = Encrypt(start, offset - messageStart);
}
//[RewriteAsync]
void WaitForHandshakeCompleted(bool initialHandshake)
{
for (; ; )
{
if (!ReadRecord())
{
_eof = true;
throw new IOException("Unexpected connection EOF in handshake");
}
Decrypt();
if (_contentType != ContentType.ChangeCipherSpec)
{
EnqueueReadData(!initialHandshake);
}
else
{
ParseChangeCipherSpec();
_waitingForChangeCipherSpec = false;
break;
}
}
while (_handshakeMessagesBuffer.Messages.Count == 0)
{
if (!ReadRecord())
{
_eof = true;
throw new IOException("Unexpected connection EOF in handshake");
}
Decrypt();
if (_contentType != ContentType.Handshake)
{
EnqueueReadData(!initialHandshake);
}
else
{
_handshakeMessagesBuffer.AddBytes(_buf, _plaintextStart, _plaintextLen, HandshakeMessagesBuffer.IgnoreHelloRequestsSettings.IgnoreHelloRequestsUntilFinished);
}
}
if ((HandshakeType)_handshakeMessagesBuffer.Messages[0][0] == HandshakeType.Finished)
{
ParseFinishedMessage(_handshakeMessagesBuffer.Messages[0]);
_handshakeMessagesBuffer.RemoveFirst(); // Leave possible hello requests after this position
}
else
{
SendAlertFatal(AlertDescription.UnexpectedMessage);
}
}
#endregion
#region Handshake messages
HandshakeType SendClientHello(ref int offset)
{
_pendingConnState = new ConnectionState();
_handshakeData = new HandshakeData();
_handshakeData.HandshakeHash1 = new SHA256CryptoServiceProvider();
_handshakeData.HandshakeHash2 = new SHA256CryptoServiceProvider();
_handshakeData.HandshakeHash1_384 = new SHA384CryptoServiceProvider();
_handshakeData.HandshakeHash2_384 = new SHA384CryptoServiceProvider();
_handshakeData.HandshakeHash1_MD5SHA1 = new MD5SHA1();
_handshakeData.HandshakeHash2_MD5SHA1 = new MD5SHA1();
_handshakeData.CertificateVerifyHash_MD5 = new MD5CryptoServiceProvider();
_handshakeData.CertificateVerifyHash_SHA1 = new SHA1CryptoServiceProvider();
// Highest version supported
offset += Utils.WriteUInt16(_buf, offset, (ushort)HighestTlsVersionSupported);
// Client random
var timestamp = (uint)DateTime.UtcNow.Subtract(new DateTime(1970, 1, 1)).TotalSeconds;
_pendingConnState.ClientRandom = new byte[32];
_rng.GetBytes(_pendingConnState.ClientRandom);
Utils.WriteUInt32(_pendingConnState.ClientRandom, 0, timestamp);
Buffer.BlockCopy(_pendingConnState.ClientRandom, 0, _buf, offset, 32);
offset += 32;
// No session id
_buf[offset++] = 0;
// Cipher suites
var supportedCipherSuites = CipherSuiteInfo.Supported;
/*
if (HighestTlsVersionSupported != TlsVersion.TLSv1_2)
supportedCipherSuites = supportedCipherSuites.Where(cs => cs.IsAllowedBefore1_2).ToArray();
*/
offset += Utils.WriteUInt16(_buf, offset, (ushort)(supportedCipherSuites.Length * sizeof(ushort)));
foreach (var suite in supportedCipherSuites)
{
offset += Utils.WriteUInt16(_buf, offset, (ushort)suite.Id);
}
// Compression methods
_buf[offset++] = 1; // Length
_buf[offset++] = 0; // "null" compression method
// Extensions length, fill in later
var extensionLengthOffset = offset;
offset += 2;
// Renegotiation extension
offset += Utils.WriteUInt16(_buf, offset, (ushort)ExtensionType.RenegotiationInfo);
if (_connState.SecureRenegotiation)
{
// Extension length
offset += Utils.WriteUInt16(_buf, offset, 13);
// Renegotiated connection length
_buf[offset++] = 12;
// Renegotiated connection data
Buffer.BlockCopy(_connState.ClientVerifyData, 0, _buf, offset, 12);
offset += 12;
}
else
{
// Extension length
offset += Utils.WriteUInt16(_buf, offset, 1);
// Renegotiated connection length
_buf[offset++] = 0;
}
// SNI extension
if (_hostName != null)
{
// TODO: IDN Unicode -> Punycode
// NOTE: IP addresses should not use SNI extension, per specification.
System.Net.IPAddress ip;
if (!System.Net.IPAddress.TryParse(_hostName, out ip))
{
offset += Utils.WriteUInt16(_buf, offset, (ushort)ExtensionType.ServerName);
var byteLen = Encoding.ASCII.GetBytes(_hostName, 0, _hostName.Length, _buf, offset + 7);
offset += Utils.WriteUInt16(_buf, offset, (ushort)(5 + byteLen));
offset += Utils.WriteUInt16(_buf, offset, (ushort)(3 + byteLen));
_buf[offset++] = 0; // host_name
offset += Utils.WriteUInt16(_buf, offset, (ushort)byteLen);
offset += byteLen;
}
}
if (HighestTlsVersionSupported == TlsVersion.TLSv1_2)
{
// Signature algorithms extension. At least IIS 7.5 needs this or it immediately resets the connection.
// Used to specify what kind of server certificate hash/signature algorithms we can use to verify it.
offset += Utils.WriteUInt16(_buf, offset, (ushort)ExtensionType.SignatureAlgorithms);
offset += Utils.WriteUInt16(_buf, offset, 20);
offset += Utils.WriteUInt16(_buf, offset, 18);
_buf[offset++] = (byte)TLSHashAlgorithm.SHA1;
_buf[offset++] = (byte)SignatureAlgorithm.ECDSA;
_buf[offset++] = (byte)TLSHashAlgorithm.SHA256;
_buf[offset++] = (byte)SignatureAlgorithm.ECDSA;
_buf[offset++] = (byte)TLSHashAlgorithm.SHA384;
_buf[offset++] = (byte)SignatureAlgorithm.ECDSA;
_buf[offset++] = (byte)TLSHashAlgorithm.SHA512;
_buf[offset++] = (byte)SignatureAlgorithm.ECDSA;
_buf[offset++] = (byte)TLSHashAlgorithm.SHA1;
_buf[offset++] = (byte)SignatureAlgorithm.RSA;
_buf[offset++] = (byte)TLSHashAlgorithm.SHA256;
_buf[offset++] = (byte)SignatureAlgorithm.RSA;
_buf[offset++] = (byte)TLSHashAlgorithm.SHA384;
_buf[offset++] = (byte)SignatureAlgorithm.RSA;
_buf[offset++] = (byte)TLSHashAlgorithm.SHA512;
_buf[offset++] = (byte)SignatureAlgorithm.RSA;
_buf[offset++] = (byte)TLSHashAlgorithm.SHA1;
_buf[offset++] = (byte)SignatureAlgorithm.DSA;
}
if (supportedCipherSuites.Any(s => s.KeyExchange == KeyExchange.ECDHE_RSA || s.KeyExchange == KeyExchange.ECDHE_ECDSA))
{
// Supported Elliptic Curves Extension
offset += Utils.WriteUInt16(_buf, offset, (ushort)ExtensionType.SupportedEllipticCurves);
offset += Utils.WriteUInt16(_buf, offset, 8);
offset += Utils.WriteUInt16(_buf, offset, 6);
offset += Utils.WriteUInt16(_buf, offset, (ushort)NamedCurve.secp256r1);
offset += Utils.WriteUInt16(_buf, offset, (ushort)NamedCurve.secp384r1);
offset += Utils.WriteUInt16(_buf, offset, (ushort)NamedCurve.secp521r1);
// Supported Point Formats Extension
offset += Utils.WriteUInt16(_buf, offset, (ushort)ExtensionType.SupportedPointFormats);
offset += Utils.WriteUInt16(_buf, offset, 2);
_buf[offset++] = 1; // Length
_buf[offset++] = 0; // Uncompressed
}
Utils.WriteUInt16(_buf, extensionLengthOffset, (ushort)(offset - (extensionLengthOffset + 2)));
return HandshakeType.ClientHello;
}
void ParseServerHelloMessage(byte[] buf, ref int pos, int endPos)
{
var renegotiating = _connState.ReadAes != null;
var version = (TlsVersion)Utils.ReadUInt16(buf, ref pos);
if (version < TlsVersion.TLSv1_0 || version > TlsVersion.TLSv1_2)
{
SendAlertFatal(AlertDescription.ProtocolVersion);
}
_connState.TlsVersion = version;
_pendingConnState.TlsVersion = version;
_pendingConnState.ServerRandom = new byte[32];
Buffer.BlockCopy(buf, pos, _pendingConnState.ServerRandom, 0, 32);
pos += 32;
// Skip session id
var sessionIDLength = buf[pos++];
pos += sessionIDLength;
var cipherSuite = (CipherSuite)Utils.ReadUInt16(buf, ref pos);
var compressionMethod = buf[pos++];
_pendingConnState.CipherSuite = CipherSuiteInfo.Supported.FirstOrDefault(s => s.Id == cipherSuite);
if (_pendingConnState.CipherSuite == null || !_pendingConnState.CipherSuite.IsAllowedBefore1_2 && version != TlsVersion.TLSv1_2 || compressionMethod != 0)
{
SendAlertFatal(AlertDescription.IllegalParameter);
}
if (_pendingConnState.TlsVersion == TlsVersion.TLSv1_2)
{
switch (_pendingConnState.CipherSuite.PRFAlgorithm)
{
case PRFAlgorithm.TLSPrfSHA256:
_handshakeData.HandshakeHash1_384.Clear();
_handshakeData.HandshakeHash1_384 = null;
_handshakeData.HandshakeHash2_384.Clear();
_handshakeData.HandshakeHash2_384 = null;
break;
case PRFAlgorithm.TLSPrfSHA384:
_handshakeData.HandshakeHash1.Clear();
_handshakeData.HandshakeHash1 = _handshakeData.HandshakeHash1_384;
_handshakeData.HandshakeHash1_384 = null;
_handshakeData.HandshakeHash2.Clear();
_handshakeData.HandshakeHash2 = _handshakeData.HandshakeHash2_384;
_handshakeData.HandshakeHash2_384 = null;
break;
default:
throw new InvalidOperationException();
}
_handshakeData.HandshakeHash1_MD5SHA1.Clear();
_handshakeData.HandshakeHash1_MD5SHA1 = null;
_handshakeData.HandshakeHash2_MD5SHA1.Clear();
_handshakeData.HandshakeHash2_MD5SHA1 = null;
_handshakeData.CertificateVerifyHash_MD5.Clear();
_handshakeData.CertificateVerifyHash_MD5 = null;
}
else
{
_handshakeData.HandshakeHash1.Clear();
_handshakeData.HandshakeHash1 = null;
_handshakeData.HandshakeHash2.Clear();
_handshakeData.HandshakeHash2 = null;
_handshakeData.HandshakeHash1_384.Clear();
_handshakeData.HandshakeHash1_384 = null;
_handshakeData.HandshakeHash2_384.Clear();
_handshakeData.HandshakeHash2_384 = null;
_handshakeData.HandshakeHash1 = _handshakeData.HandshakeHash1_MD5SHA1;
_handshakeData.HandshakeHash1_MD5SHA1 = null;
_handshakeData.HandshakeHash2 = _handshakeData.HandshakeHash2_MD5SHA1;
_handshakeData.HandshakeHash2_MD5SHA1 = null;
}
// If no extensions present, return
if (pos == endPos)
return;
var processedRenegotiationInfo = false;
var extensionLength = Utils.ReadUInt16(buf, ref pos);
var extensionsEnd = pos + extensionLength;
while (pos < extensionsEnd)
{
var extensionId = (ExtensionType)Utils.ReadUInt16(buf, ref pos);
switch (extensionId)
{
case ExtensionType.RenegotiationInfo:
if (processedRenegotiationInfo)
SendAlertFatal(AlertDescription.HandshakeFailure);
processedRenegotiationInfo = true;
var lengthFull = Utils.ReadUInt16(buf, ref pos);
var length = buf[pos++];
if (length + 1 != lengthFull)
SendAlertFatal(AlertDescription.HandshakeFailure);
if (!renegotiating)
{
if (length != 0)
SendAlertFatal(AlertDescription.HandshakeFailure);
}
if (renegotiating)
{
if (!_connState.SecureRenegotiation)
SendAlertFatal(AlertDescription.HandshakeFailure);
if (length != 24)
SendAlertFatal(AlertDescription.HandshakeFailure);
for (var j = 0; j < 12; j++)
{
if (_connState.ClientVerifyData[j] != buf[pos++])
SendAlertFatal(AlertDescription.HandshakeFailure);
}
for (var j = 0; j < 12; j++)
{
if (_connState.ServerVerifyData[j] != buf[pos++])
SendAlertFatal(AlertDescription.HandshakeFailure);
}
}
_pendingConnState.SecureRenegotiation = true;
break;
case ExtensionType.SupportedEllipticCurves:
var len = Utils.ReadUInt16(buf, ref pos);
// Contains in what formats the server can parse. Ignore it.
pos += len;
break;
case ExtensionType.SupportedPointFormats:
var length1 = Utils.ReadUInt16(buf, ref pos);
// Contains in what formats the server can parse. Ignore it.
pos += length1;
break;
case ExtensionType.ServerName:
var length2 = Utils.ReadUInt16(buf, ref pos);
pos += length2;
if (length2 != 0)
SendAlertFatal(AlertDescription.IllegalParameter);
break;
default:
SendAlertFatal(AlertDescription.IllegalParameter);
break;
}
}
if (!processedRenegotiationInfo && (!renegotiating && _noRenegotiationExtensionSupportIsFatal || renegotiating && _connState.SecureRenegotiation))
{
SendAlertFatal(AlertDescription.HandshakeFailure);
}
}
void ParseCertificateMessage(byte[] buf, ref int pos)
{
_handshakeData.CertList = new List<X509Certificate2>();
_handshakeData.CertChain = new X509Chain();
_handshakeData.CertChain.ChainPolicy.RevocationMode = _checkCertificateRevocation ? X509RevocationMode.Online : X509RevocationMode.NoCheck;
var errors = System.Net.Security.SslPolicyErrors.None;
var totalLen = Utils.ReadUInt24(buf, ref pos);
if (totalLen == 0)
SendAlertFatal(AlertDescription.IllegalParameter);
int endPos = pos + totalLen;
while (pos < endPos)
{
var certLen = Utils.ReadUInt24(buf, ref pos);
var certBytes = new byte[certLen];
Buffer.BlockCopy(buf, pos, certBytes, 0, certLen);
pos += certLen;
try
{
var cert = new X509Certificate2(certBytes);
if (_handshakeData.CertList.Count != 0)
_handshakeData.CertChain.ChainPolicy.ExtraStore.Add(cert);
_handshakeData.CertList.Add(cert);
}
catch (CryptographicException e)
{
SendAlertFatal(AlertDescription.BadCertificate, e.Message);
}
}
if (_handshakeData.CertList.Count == 0)
{
SendAlertFatal(AlertDescription.CertificateUnknown, "No certificate was provided by the server");
}
// Validate certificate
_handshakeData.CertChain.Build(_handshakeData.CertList[0]);
var hostnameError = false;
if (!string.IsNullOrEmpty(_hostName))
{
hostnameError = !Utils.HostnameInCertificate(_handshakeData.CertList[0], _hostName);
if (hostnameError)
errors |= System.Net.Security.SslPolicyErrors.RemoteCertificateNameMismatch;
}
var hasChainStatus = _handshakeData.CertChain.ChainStatus != null;
if (hasChainStatus && _handshakeData.CertChain.ChainStatus.Length > 0)
{
errors |= System.Net.Security.SslPolicyErrors.RemoteCertificateChainErrors;
}
bool success = _remoteCertificationValidationCallback != null
? _remoteCertificationValidationCallback(this, _handshakeData.CertList[0], _handshakeData.CertChain, errors)
: errors == System.Net.Security.SslPolicyErrors.None;
if (!success)
{
if (hasChainStatus && _handshakeData.CertChain.ChainStatus.Any(s => (s.Status & X509ChainStatusFlags.NotTimeValid) != 0))
SendAlertFatal(AlertDescription.CertificateExpired);
else if (_handshakeData.CertChain.ChainStatus.Any(s => (s.Status & X509ChainStatusFlags.Revoked) != 0))
SendAlertFatal(AlertDescription.CertificateRevoked);
else
{
var errorMsg = "Server certificate was not accepted.";