int CEncryptedDatagramSocket::EncryptSendServer(uchar** ppbyBuf, int nBufLen, uint32 dwBaseKey) const{
ASSERT( thePrefs.IsServerCryptLayerUDPEnabled() );
ASSERT( dwBaseKey != 0 );
uint8 byPadLen = 0; // padding disabled for UDP currently
uint32 nCryptedLen = nBufLen + byPadLen + CRYPT_HEADER_WITHOUTPADDING;
uchar* pachCryptedBuffer = new uchar[nCryptedLen];
uint16 nRandomKeyPart = (uint16)cryptRandomGen.GenerateWord32(0x0000, 0xFFFF);
uchar achKeyData[7];
memcpy(achKeyData, &dwBaseKey, 4);
achKeyData[4] = MAGICVALUE_UDP_CLIENTSERVER;
memcpy(achKeyData + 5, &nRandomKeyPart, 2);
MD5Sum md5(achKeyData, sizeof(achKeyData));
RC4_Key_Struct keySendKey;
RC4CreateKey(md5.GetRawHash(), 16, &keySendKey, true);
// create the semi random byte encryption header
uint8 bySemiRandomNotProtocolMarker = 0;
int i;
for (i = 0; i < 128; i++){
bySemiRandomNotProtocolMarker = cryptRandomGen.GenerateByte();
if (bySemiRandomNotProtocolMarker != OP_EDONKEYPROT) // not allowed values
break;
}
if (i >= 128){
// either we have _real_ bad luck or the randomgenerator is a bit messed up
ASSERT( false );
bySemiRandomNotProtocolMarker = 0x01;
}
uint32 dwMagicValue = MAGICVALUE_UDP_SYNC_SERVER;
pachCryptedBuffer[0] = bySemiRandomNotProtocolMarker;
memcpy(pachCryptedBuffer + 1, &nRandomKeyPart, 2);
RC4Crypt((uchar*)&dwMagicValue, pachCryptedBuffer + 3, 4, &keySendKey);
RC4Crypt((uchar*)&byPadLen, pachCryptedBuffer + 7, 1, &keySendKey);
for (int j = 0; j < byPadLen; j++){
uint8 byRand = (uint8)rand(); // they actually dont really need to be random, but it doesn't hurts either
RC4Crypt((uchar*)&byRand, pachCryptedBuffer + CRYPT_HEADER_WITHOUTPADDING + j, 1, &keySendKey);
}
RC4Crypt(*ppbyBuf, pachCryptedBuffer + CRYPT_HEADER_WITHOUTPADDING + byPadLen, nBufLen, &keySendKey);
delete[] *ppbyBuf;
*ppbyBuf = pachCryptedBuffer;
//Xman
// Maella -Accurate measure of bandwidth: eDonkey data + control, network adapter-
/*
theStats.AddUpDataOverheadCrypt(nCryptedLen - nBufLen);
*/
theApp.pBandWidthControl->AddeMuleOutObfuscationUDP(nCryptedLen - nBufLen);
//Xman end
return nCryptedLen;
}
uint8_t CEncryptedStreamSocket::GetSemiRandomNotProtocolMarker() const{
uint8_t bySemiRandomNotProtocolMarker = 0;
int i;
for (i = 0; i < 128; i++){
bySemiRandomNotProtocolMarker = cryptRandomGen.GenerateByte();
bool bOk = false;
switch (bySemiRandomNotProtocolMarker){ // not allowed values
case OP_EDONKEYPROT:
case OP_PACKEDPROT:
case OP_EMULEPROT:
break;
default:
bOk = true;
}
if (bOk)
break;
}
if (i >= 128){
// either we have _real_ bad luck or the randomgenerator is a bit messed up
ASSERT( false );
bySemiRandomNotProtocolMarker = 0x01;
}
return bySemiRandomNotProtocolMarker;
}
// Encrypt packet. Key used:
// pachClientHashOrKadID != NULL -> pachClientHashOrKadID
// pachClientHashOrKadID == NULL && bKad && nReceiverVerifyKey != 0 -> nReceiverVerifyKey
// else -> ASSERT
int CEncryptedDatagramSocket::EncryptSendClient(uchar** ppbyBuf, int nBufLen, const uchar* pachClientHashOrKadID, bool bKad, uint32 nReceiverVerifyKey, uint32 nSenderVerifyKey) const{
ASSERT( theApp.GetPublicIP() != 0 || bKad );
ASSERT( thePrefs.IsClientCryptLayerSupported() );
ASSERT( pachClientHashOrKadID != NULL || nReceiverVerifyKey != 0 );
ASSERT( (nReceiverVerifyKey == 0 && nSenderVerifyKey == 0) || bKad );
uint8 byPadLen = 0; // padding disabled for UDP currently
const uint32 nCryptHeaderLen = byPadLen + CRYPT_HEADER_WITHOUTPADDING + (bKad ? 8 : 0);
uint32 nCryptedLen = nBufLen + nCryptHeaderLen;
uchar* pachCryptedBuffer = new uchar[nCryptedLen];
bool bKadRecKeyUsed = false;
uint16 nRandomKeyPart = (uint16)cryptRandomGen.GenerateWord32(0x0000, 0xFFFF);
MD5Sum md5;
if (bKad){
if ((pachClientHashOrKadID == NULL || isnulmd4(pachClientHashOrKadID)) && nReceiverVerifyKey != 0) {
bKadRecKeyUsed = true;
uchar achKeyData[6];
PokeUInt32(achKeyData, nReceiverVerifyKey);
PokeUInt16(achKeyData+4, nRandomKeyPart);
md5.Calculate(achKeyData, sizeof(achKeyData));
//DEBUG_ONLY( DebugLog(_T("Creating obfuscated Kad packet encrypted by ReceiverKey (%u)"), nReceiverVerifyKey) );
}
else if (pachClientHashOrKadID != NULL && !isnulmd4(pachClientHashOrKadID)) {
uchar achKeyData[18];
md4cpy(achKeyData, pachClientHashOrKadID);
PokeUInt16(achKeyData+16, nRandomKeyPart);
md5.Calculate(achKeyData, sizeof(achKeyData));
//DEBUG_ONLY( DebugLog(_T("Creating obfuscated Kad packet encrypted by Hash/NodeID %s"), md4str(pachClientHashOrKadID)) );
}
else {
ASSERT( false );
delete[] pachCryptedBuffer;
return nBufLen;
}
}
else{
uchar achKeyData[23];
md4cpy(achKeyData, pachClientHashOrKadID);
uint32 dwIP = theApp.GetPublicIP();
memcpy(achKeyData+16, &dwIP, 4);
memcpy(achKeyData+21, &nRandomKeyPart, 2);
achKeyData[20] = MAGICVALUE_UDP;
md5.Calculate(achKeyData, sizeof(achKeyData));
}
RC4_Key_Struct keySendKey;
RC4CreateKey(md5.GetRawHash(), 16, &keySendKey, true);
// create the semi random byte encryption header
uint8 bySemiRandomNotProtocolMarker = 0;
int i;
for (i = 0; i < 128; i++){
bySemiRandomNotProtocolMarker = cryptRandomGen.GenerateByte();
bySemiRandomNotProtocolMarker = bKad ? (bySemiRandomNotProtocolMarker & 0xFE) : (bySemiRandomNotProtocolMarker | 0x01); // set the ed2k/kad marker bit
if (bKad)
bySemiRandomNotProtocolMarker = bKadRecKeyUsed ? ((bySemiRandomNotProtocolMarker & 0xFE) | 0x02) : (bySemiRandomNotProtocolMarker & 0xFC); // set the ed2k/kad and nodeid/reckey markerbit
else
bySemiRandomNotProtocolMarker = (bySemiRandomNotProtocolMarker | 0x01); // set the ed2k/kad marker bit
bool bOk = false;
switch (bySemiRandomNotProtocolMarker){ // not allowed values
case OP_EMULEPROT:
case OP_KADEMLIAPACKEDPROT:
case OP_KADEMLIAHEADER:
case OP_UDPRESERVEDPROT1:
case OP_UDPRESERVEDPROT2:
case OP_PACKEDPROT:
break;
default:
bOk = true;
}
if (bOk)
break;
}
if (i >= 128){
// either we have _really_ bad luck or the randomgenerator is a bit messed up
ASSERT( false );
bySemiRandomNotProtocolMarker = 0x01;
}
uint32 dwMagicValue = MAGICVALUE_UDP_SYNC_CLIENT;
pachCryptedBuffer[0] = bySemiRandomNotProtocolMarker;
memcpy(pachCryptedBuffer + 1, &nRandomKeyPart, 2);
RC4Crypt((uchar*)&dwMagicValue, pachCryptedBuffer + 3, 4, &keySendKey);
RC4Crypt((uchar*)&byPadLen, pachCryptedBuffer + 7, 1, &keySendKey);
for (int j = 0; j < byPadLen; j++){
uint8 byRand = (uint8)rand(); // they actually dont really need to be random, but it doesn't hurts either
RC4Crypt((uchar*)&byRand, pachCryptedBuffer + CRYPT_HEADER_WITHOUTPADDING + j, 1, &keySendKey);
}
if (bKad){
RC4Crypt((uchar*)&nReceiverVerifyKey, pachCryptedBuffer + CRYPT_HEADER_WITHOUTPADDING + byPadLen, 4, &keySendKey);
RC4Crypt((uchar*)&nSenderVerifyKey, pachCryptedBuffer + CRYPT_HEADER_WITHOUTPADDING + byPadLen + 4, 4, &keySendKey);
}
RC4Crypt(*ppbyBuf, pachCryptedBuffer + nCryptHeaderLen, nBufLen, &keySendKey);
delete[] *ppbyBuf;
*ppbyBuf = pachCryptedBuffer;
//Xman
// Maella -Accurate measure of bandwidth: eDonkey data + control, network adapter-
/*
theStats.AddUpDataOverheadCrypt(nCryptedLen - nBufLen);
*/
theApp.pBandWidthControl->AddeMuleOutObfuscationUDP(nCryptedLen - nBufLen);
//Xman end
return nCryptedLen;
}
int CEncryptedDatagramSocket::EncryptSendClient(uchar** ppbyBuf, int nBufLen, const uchar* pachClientHashOrKadID, bool bKad, uint16 nReceiverVerifyKey, uint16 nSenderVerifyKey) const{
ASSERT( theApp.GetPublicIP() != 0 || bKad );
ASSERT( thePrefs.IsClientCryptLayerSupported() );
uint8 byPadLen = 0; // padding disabled for UDP currently
const uint32 nCryptHeaderLen = byPadLen + CRYPT_HEADER_WITHOUTPADDING + (bKad ? 4 : 0);
uint32 nCryptedLen = nBufLen + nCryptHeaderLen;
uchar* pachCryptedBuffer = new uchar[nCryptedLen];
uint16 nRandomKeyPart = (uint16)cryptRandomGen.GenerateWord32(0x0000, 0xFFFF);
MD5Sum md5;
if (bKad){
uchar achKeyData[18];
md4cpy(achKeyData, pachClientHashOrKadID);
memcpy(achKeyData+16, &nRandomKeyPart, 2);
md5.Calculate(achKeyData, sizeof(achKeyData));
}
else{
uchar achKeyData[23];
md4cpy(achKeyData, pachClientHashOrKadID);
uint32 dwIP = theApp.GetPublicIP();
memcpy(achKeyData+16, &dwIP, 4);
memcpy(achKeyData+21, &nRandomKeyPart, 2);
achKeyData[20] = MAGICVALUE_UDP;
md5.Calculate(achKeyData, sizeof(achKeyData));
}
RC4_Key_Struct keySendKey;
RC4CreateKey(md5.GetRawHash(), 16, &keySendKey, true);
// create the semi random byte encryption header
uint8 bySemiRandomNotProtocolMarker = 0;
int i;
for (i = 0; i < 128; i++){
bySemiRandomNotProtocolMarker = cryptRandomGen.GenerateByte();
bySemiRandomNotProtocolMarker = bKad ? (bySemiRandomNotProtocolMarker & 0xFE) : (bySemiRandomNotProtocolMarker | 0x01); // set the ed2k/kad marker bit
bool bOk = false;
switch (bySemiRandomNotProtocolMarker){ // not allowed values
case OP_EMULEPROT:
case OP_KADEMLIAPACKEDPROT:
case OP_KADEMLIAHEADER:
case OP_UDPRESERVEDPROT1:
case OP_UDPRESERVEDPROT2:
case OP_PACKEDPROT:
break;
default:
bOk = true;
}
if (bOk)
break;
}
if (i >= 128){
// either we have _real_ bad luck or the randomgenerator is a bit messed up
ASSERT( false );
bySemiRandomNotProtocolMarker = 0x01;
}
uint32 dwMagicValue = MAGICVALUE_UDP_SYNC_CLIENT;
pachCryptedBuffer[0] = bySemiRandomNotProtocolMarker;
memcpy(pachCryptedBuffer + 1, &nRandomKeyPart, 2);
RC4Crypt((uchar*)&dwMagicValue, pachCryptedBuffer + 3, 4, &keySendKey);
RC4Crypt((uchar*)&byPadLen, pachCryptedBuffer + 7, 1, &keySendKey);
for (int j = 0; j < byPadLen; j++){
uint8 byRand = (uint8)rand(); // they actually dont really need to be random, but it doesn't hurts either
RC4Crypt((uchar*)&byRand, pachCryptedBuffer + CRYPT_HEADER_WITHOUTPADDING + j, 1, &keySendKey);
}
if (bKad){
RC4Crypt((uchar*)&nReceiverVerifyKey, pachCryptedBuffer + CRYPT_HEADER_WITHOUTPADDING + byPadLen, 2, &keySendKey);
RC4Crypt((uchar*)&nSenderVerifyKey, pachCryptedBuffer + CRYPT_HEADER_WITHOUTPADDING + byPadLen + 2, 2, &keySendKey);
}
RC4Crypt(*ppbyBuf, pachCryptedBuffer + nCryptHeaderLen, nBufLen, &keySendKey);
delete[] *ppbyBuf;
*ppbyBuf = pachCryptedBuffer;
theStats.AddUpDataOverheadCrypt(nCryptedLen - nBufLen);
return nCryptedLen;
}
int CEncryptedStreamSocket::Negotiate(const uchar* pBuffer, uint32_t nLen){
uint32_t nRead = 0;
ASSERT( m_nReceiveBytesWanted > 0 );
try{
while (m_NegotiatingState != ONS_COMPLETE && m_nReceiveBytesWanted > 0){
if (m_nReceiveBytesWanted > 512){
ASSERT( false );
return 0;
}
if (m_pfiReceiveBuffer == NULL){
BYTE* pReceiveBuffer = (BYTE*)malloc(512); // use a fixed size buffer
if (pReceiveBuffer == NULL)
AfxThrowMemoryException();
m_pfiReceiveBuffer = new CSafeMemFile(pReceiveBuffer, 512);
}
const uint32_t nToRead = min(nLen - nRead, m_nReceiveBytesWanted);
m_pfiReceiveBuffer->Write(pBuffer + nRead, nToRead);
nRead += nToRead;
m_nReceiveBytesWanted -= nToRead;
if (m_nReceiveBytesWanted > 0)
return nRead;
const uint32_t nCurrentBytesLen = (uint32_t)m_pfiReceiveBuffer->GetPosition();
if (m_NegotiatingState != ONS_BASIC_CLIENTA_RANDOMPART && m_NegotiatingState != ONS_BASIC_SERVER_DHANSWER){ // don't have the keys yet
BYTE* pCryptBuffer = m_pfiReceiveBuffer->Detach();
RC4Crypt(pCryptBuffer, pCryptBuffer, nCurrentBytesLen, m_pRC4ReceiveKey);
m_pfiReceiveBuffer->Attach(pCryptBuffer, 512);
}
m_pfiReceiveBuffer->SeekToBegin();
switch (m_NegotiatingState){
case ONS_NONE: // would be a bug
ASSERT( false );
return 0;
case ONS_BASIC_CLIENTA_RANDOMPART:{
ASSERT( m_pRC4ReceiveKey == NULL );
uchar achKeyData[21];
md4cpy(achKeyData, thePrefs.GetUserHash());
achKeyData[16] = MAGICVALUE_REQUESTER;
m_pfiReceiveBuffer->Read(achKeyData + 17, 4); // random key part sent from remote client
MD5Sum md5(achKeyData, sizeof(achKeyData));
m_pRC4ReceiveKey = RC4CreateKey(md5.GetRawHash(), 16, NULL);
achKeyData[16] = MAGICVALUE_SERVER;
md5.Calculate(achKeyData, sizeof(achKeyData));
m_pRC4SendKey = RC4CreateKey(md5.GetRawHash(), 16, NULL);
m_NegotiatingState = ONS_BASIC_CLIENTA_MAGICVALUE;
m_nReceiveBytesWanted = 4;
break;
}
case ONS_BASIC_CLIENTA_MAGICVALUE:{
uint32_t dwValue = m_pfiReceiveBuffer->ReadUInt32();
if (dwValue == MAGICVALUE_SYNC){
// yup, the one or the other way it worked, this is an encrypted stream
//DEBUG_ONLY( DebugLog(_T("Received proper magic value, clientIP: %s"), DbgGetIPString()) );
// set the receiver key
m_NegotiatingState = ONS_BASIC_CLIENTA_METHODTAGSPADLEN;
m_nReceiveBytesWanted = 3;
}
else{
DebugLogError(_T("CEncryptedStreamSocket: Received wrong magic value from clientIP %s on a supposly encrytped stream / Wrong Header"), DbgGetIPString());
OnError(ERR_ENCRYPTION);
return (-1);
}
break;
}
case ONS_BASIC_CLIENTA_METHODTAGSPADLEN:
m_dbgbyEncryptionSupported = m_pfiReceiveBuffer->ReadUInt8();
m_dbgbyEncryptionRequested = m_pfiReceiveBuffer->ReadUInt8();
if (m_dbgbyEncryptionRequested != ENM_OBFUSCATION)
AddDebugLogLine(DLP_LOW, false, _T("CEncryptedStreamSocket: Client %s preffered unsupported encryption method (%i)"), DbgGetIPString(), m_dbgbyEncryptionRequested);
m_nReceiveBytesWanted = m_pfiReceiveBuffer->ReadUInt8();
m_NegotiatingState = ONS_BASIC_CLIENTA_PADDING;
//if (m_nReceiveBytesWanted > 16)
// AddDebugLogLine(DLP_LOW, false, _T("CEncryptedStreamSocket: Client %s sent more than 16 (%i) padding bytes"), DbgGetIPString(), m_nReceiveBytesWanted);
if (m_nReceiveBytesWanted > 0)
break;
case ONS_BASIC_CLIENTA_PADDING:{
// ignore the random bytes, send the response, set status complete
CSafeMemFile fileResponse(26);
fileResponse.WriteUInt32(MAGICVALUE_SYNC);
const uint8_t bySelectedEncryptionMethod = ENM_OBFUSCATION; // we do not support any further encryption in this version, so no need to look which the other client preferred
fileResponse.WriteUInt8(bySelectedEncryptionMethod);
SOCKADDR_IN sockAddr = {0};
int nSockAddrLen = sizeof(sockAddr);
GetPeerName((SOCKADDR*)&sockAddr, &nSockAddrLen);
const uint8_t byPaddingLen = theApp.serverconnect->AwaitingTestFromIP(sockAddr.sin_addr.S_un.S_addr) ? 16 : (thePrefs.GetCryptTCPPaddingLength() + 1);
uint8_t byPadding = (uint8_t)(cryptRandomGen.GenerateByte() % byPaddingLen);
fileResponse.WriteUInt8(byPadding);
for (int i = 0; i < byPadding; i++)
fileResponse.WriteUInt8(static_cast<uint8_t>(rand() & 0xFF));
SendNegotiatingData(fileResponse.GetBuffer(), (uint32_t)fileResponse.GetLength());
m_NegotiatingState = ONS_COMPLETE;
m_StreamCryptState = ECS_ENCRYPTING;
//DEBUG_ONLY( DebugLog(_T("CEncryptedStreamSocket: Finished Obufscation handshake with client %s (incoming)"), DbgGetIPString()) );
break;
}
case ONS_BASIC_CLIENTB_MAGICVALUE:{
if (m_pfiReceiveBuffer->ReadUInt32() != MAGICVALUE_SYNC){
DebugLogError(_T("CEncryptedStreamSocket: EncryptedstreamSyncError: Client sent wrong Magic Value as answer, cannot complete handshake (%s)"), DbgGetIPString());
OnError(ERR_ENCRYPTION);
return (-1);
}
m_NegotiatingState = ONS_BASIC_CLIENTB_METHODTAGSPADLEN;
m_nReceiveBytesWanted = 2;
break;
}
case ONS_BASIC_CLIENTB_METHODTAGSPADLEN:{
m_dbgbyEncryptionMethodSet = m_pfiReceiveBuffer->ReadUInt8();
if (m_dbgbyEncryptionMethodSet != ENM_OBFUSCATION){
DebugLogError( _T("CEncryptedStreamSocket: Client %s set unsupported encryption method (%i), handshake failed"), DbgGetIPString(), m_dbgbyEncryptionMethodSet);
OnError(ERR_ENCRYPTION);
return (-1);
}
m_nReceiveBytesWanted = m_pfiReceiveBuffer->ReadUInt8();
m_NegotiatingState = ONS_BASIC_CLIENTB_PADDING;
if (m_nReceiveBytesWanted > 0)
break;
}
case ONS_BASIC_CLIENTB_PADDING:
// ignore the random bytes, the handshake is complete
m_NegotiatingState = ONS_COMPLETE;
m_StreamCryptState = ECS_ENCRYPTING;
//DEBUG_ONLY( DebugLog(_T("CEncryptedStreamSocket: Finished Obufscation handshake with client %s (outgoing)"), DbgGetIPString()) );
break;
case ONS_BASIC_SERVER_DHANSWER:{
ASSERT( !m_cryptDHA.IsZero() );
uchar aBuffer[PRIMESIZE_BYTES + 1];
m_pfiReceiveBuffer->Read(aBuffer, PRIMESIZE_BYTES);
CryptoPP::Integer cryptDHAnswer((byte*)aBuffer, PRIMESIZE_BYTES);
CryptoPP::Integer cryptDHPrime((byte*)dh768_p, PRIMESIZE_BYTES); // our fixed prime
CryptoPP::Integer cryptResult = CryptoPP::a_exp_b_mod_c(cryptDHAnswer, m_cryptDHA, cryptDHPrime);
m_cryptDHA = 0;
DEBUG_ONLY( ZeroMemory(aBuffer, sizeof(aBuffer)) );
ASSERT( cryptResult.MinEncodedSize() <= PRIMESIZE_BYTES );
// create the keys
cryptResult.Encode(aBuffer, PRIMESIZE_BYTES);
aBuffer[PRIMESIZE_BYTES] = MAGICVALUE_REQUESTER;
MD5Sum md5(aBuffer, sizeof(aBuffer));
m_pRC4SendKey = RC4CreateKey(md5.GetRawHash(), 16, NULL);
aBuffer[PRIMESIZE_BYTES] = MAGICVALUE_SERVER;
md5.Calculate(aBuffer, sizeof(aBuffer));
m_pRC4ReceiveKey = RC4CreateKey(md5.GetRawHash(), 16, NULL);
m_NegotiatingState = ONS_BASIC_SERVER_MAGICVALUE;
m_nReceiveBytesWanted = 4;
break;
}
case ONS_BASIC_SERVER_MAGICVALUE:{
uint32_t dwValue = m_pfiReceiveBuffer->ReadUInt32();
if (dwValue == MAGICVALUE_SYNC){
// yup, the one or the other way it worked, this is an encrypted stream
DebugLog(_T("Received proper magic value after DH-Agreement from Serverconnection IP: %s"), DbgGetIPString());
// set the receiver key
m_NegotiatingState = ONS_BASIC_SERVER_METHODTAGSPADLEN;
m_nReceiveBytesWanted = 3;
}
else{
DebugLogError(_T("CEncryptedStreamSocket: Received wrong magic value after DH-Agreement from Serverconnection"), DbgGetIPString());
OnError(ERR_ENCRYPTION);
return (-1);
}
break;
}
case ONS_BASIC_SERVER_METHODTAGSPADLEN:
m_dbgbyEncryptionSupported = m_pfiReceiveBuffer->ReadUInt8();
m_dbgbyEncryptionRequested = m_pfiReceiveBuffer->ReadUInt8();
if (m_dbgbyEncryptionRequested != ENM_OBFUSCATION)
AddDebugLogLine(DLP_LOW, false, _T("CEncryptedStreamSocket: Server %s preffered unsupported encryption method (%i)"), DbgGetIPString(), m_dbgbyEncryptionRequested);
m_nReceiveBytesWanted = m_pfiReceiveBuffer->ReadUInt8();
m_NegotiatingState = ONS_BASIC_SERVER_PADDING;
if (m_nReceiveBytesWanted > 16)
AddDebugLogLine(DLP_LOW, false, _T("CEncryptedStreamSocket: Server %s sent more than 16 (%i) padding bytes"), DbgGetIPString(), m_nReceiveBytesWanted);
if (m_nReceiveBytesWanted > 0)
break;
case ONS_BASIC_SERVER_PADDING:{
// ignore the random bytes (they are decrypted already), send the response, set status complete
CSafeMemFile fileResponse(26);
fileResponse.WriteUInt32(MAGICVALUE_SYNC);
const uint8_t bySelectedEncryptionMethod = ENM_OBFUSCATION; // we do not support any further encryption in this version, so no need to look which the other client preferred
fileResponse.WriteUInt8(bySelectedEncryptionMethod);
uint8_t byPadding = (uint8_t)(cryptRandomGen.GenerateByte() % 16);
fileResponse.WriteUInt8(byPadding);
for (int i = 0; i < byPadding; i++)
fileResponse.WriteUInt8(static_cast<uint8_t>(rand() & 0xFF));
m_NegotiatingState = ONS_BASIC_SERVER_DELAYEDSENDING;
SendNegotiatingData(fileResponse.GetBuffer(), (uint32_t)fileResponse.GetLength(), 0, true); // don't actually send it right now, store it in our sendbuffer
m_StreamCryptState = ECS_ENCRYPTING;
DEBUG_ONLY( DebugLog(_T("CEncryptedStreamSocket: Finished DH Obufscation handshake with Server %s"), DbgGetIPString()) );
break;
}
default:
ASSERT( false );
}
m_pfiReceiveBuffer->SeekToBegin();
}
if (m_pfiReceiveBuffer != NULL)
free(m_pfiReceiveBuffer->Detach());
delete m_pfiReceiveBuffer;
m_pfiReceiveBuffer = NULL;
return nRead;
}
catch(CFileException* error){
// can only be caused by a bug in negationhandling, not by the datastream
error->Delete();
ASSERT( false );
OnError(ERR_ENCRYPTION);
if (m_pfiReceiveBuffer != NULL)
free(m_pfiReceiveBuffer->Detach());
delete m_pfiReceiveBuffer;
m_pfiReceiveBuffer = NULL;
return (-1);
}
}
void CEncryptedStreamSocket::StartNegotiation(bool bOutgoing){
if (!bOutgoing){
m_NegotiatingState = ONS_BASIC_CLIENTA_RANDOMPART;
m_StreamCryptState = ECS_NEGOTIATING;
m_nReceiveBytesWanted = 4;
}
else if (m_StreamCryptState == ECS_PENDING){
CSafeMemFile fileRequest(29);
const uint8_t bySemiRandomNotProtocolMarker = GetSemiRandomNotProtocolMarker();
fileRequest.WriteUInt8(bySemiRandomNotProtocolMarker);
fileRequest.WriteUInt32(m_nRandomKeyPart);
fileRequest.WriteUInt32(MAGICVALUE_SYNC);
const uint8_t bySupportedEncryptionMethod = ENM_OBFUSCATION; // we do not support any further encryption in this version
fileRequest.WriteUInt8(bySupportedEncryptionMethod);
fileRequest.WriteUInt8(bySupportedEncryptionMethod); // so we also prefer this one
uint8_t byPadding = (uint8_t)(cryptRandomGen.GenerateByte() % (thePrefs.GetCryptTCPPaddingLength() + 1));
fileRequest.WriteUInt8(byPadding);
for (int i = 0; i < byPadding; i++)
fileRequest.WriteUInt8(cryptRandomGen.GenerateByte());
m_NegotiatingState = ONS_BASIC_CLIENTB_MAGICVALUE;
m_StreamCryptState = ECS_NEGOTIATING;
m_nReceiveBytesWanted = 4;
SendNegotiatingData(fileRequest.GetBuffer(), (uint32_t)fileRequest.GetLength(), 5);
}
else if (m_StreamCryptState == ECS_PENDING_SERVER){
CSafeMemFile fileRequest(113);
const uint8_t bySemiRandomNotProtocolMarker = GetSemiRandomNotProtocolMarker();
fileRequest.WriteUInt8(bySemiRandomNotProtocolMarker);
m_cryptDHA.Randomize(cryptRandomGen, DHAGREEMENT_A_BITS); // our random a
ASSERT( m_cryptDHA.MinEncodedSize() <= DHAGREEMENT_A_BITS / 8 );
CryptoPP::Integer cryptDHPrime((byte*)dh768_p, PRIMESIZE_BYTES); // our fixed prime
// calculate g^a % p
CryptoPP::Integer cryptDHGexpAmodP = CryptoPP::a_exp_b_mod_c(CryptoPP::Integer(2), m_cryptDHA, cryptDHPrime);
ASSERT( m_cryptDHA.MinEncodedSize() <= PRIMESIZE_BYTES );
// put the result into a buffer
uchar aBuffer[PRIMESIZE_BYTES];
cryptDHGexpAmodP.Encode(aBuffer, PRIMESIZE_BYTES);
fileRequest.Write(aBuffer, PRIMESIZE_BYTES);
uint8_t byPadding = (uint8_t)(cryptRandomGen.GenerateByte() % 16); // add random padding
fileRequest.WriteUInt8(byPadding);
for (int i = 0; i < byPadding; i++)
fileRequest.WriteUInt8(cryptRandomGen.GenerateByte());
m_NegotiatingState = ONS_BASIC_SERVER_DHANSWER;
m_StreamCryptState = ECS_NEGOTIATING;
m_nReceiveBytesWanted = 96;
SendNegotiatingData(fileRequest.GetBuffer(), (uint32_t)fileRequest.GetLength(), (uint32_t)fileRequest.GetLength());
}
else{
ASSERT( false );
m_StreamCryptState = ECS_NONE;
return;
}
}
