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;
}
int CEncryptedDatagramSocket::DecryptReceivedServer(BYTE* pbyBufIn, int nBufLen, BYTE** ppbyBufOut, uint32 dwBaseKey, uint32 dbgIP) const{
int nResult = nBufLen;
*ppbyBufOut = pbyBufIn;
if (nResult <= CRYPT_HEADER_WITHOUTPADDING || !thePrefs.IsServerCryptLayerUDPEnabled() || dwBaseKey == 0)
return nResult;
if(pbyBufIn[0] == OP_EDONKEYPROT)
return nResult; // no encrypted packet (see description on top)
// might be an encrypted packet, try to decrypt
uchar achKeyData[7];
memcpy(achKeyData, &dwBaseKey, 4);
achKeyData[4] = MAGICVALUE_UDP_SERVERCLIENT;
memcpy(achKeyData + 5, pbyBufIn + 1, 2); // random key part sent from remote server
MD5Sum md5(achKeyData, sizeof(achKeyData));
RC4_Key_Struct keyReceiveKey;
RC4CreateKey(md5.GetRawHash(), 16, &keyReceiveKey, true);
uint32 dwValue;
RC4Crypt(pbyBufIn + 3, (uchar*)&dwValue, sizeof(dwValue), &keyReceiveKey);
if (dwValue == MAGICVALUE_UDP_SYNC_SERVER){
// yup this is an encrypted packet
if (thePrefs.GetDebugServerUDPLevel() > 0)
DEBUG_ONLY( DebugLog(_T("Received obfuscated UDP packet from ServerIP: %s"), ipstr(dbgIP)) );
uint8 byPadLen;
RC4Crypt(pbyBufIn + 7, (uchar*)&byPadLen, 1, &keyReceiveKey);
byPadLen &= 15;
nResult -= CRYPT_HEADER_WITHOUTPADDING;
if (nResult <= byPadLen){
DebugLogError(_T("Invalid obfuscated UDP packet from ServerIP: %s, Paddingsize (%u) larger than received bytes"), ipstr(dbgIP), byPadLen);
return nBufLen; // pass through, let the Receivefunction do the errorhandling on this junk
}
if (byPadLen > 0)
RC4Crypt(NULL, NULL, byPadLen, &keyReceiveKey);
nResult -= byPadLen;
*ppbyBufOut = pbyBufIn + (nBufLen - nResult);
RC4Crypt((uchar*)*ppbyBufOut, (uchar*)*ppbyBufOut, nResult, &keyReceiveKey);
//Xman
// Maella -Accurate measure of bandwidth: eDonkey data + control, network adapter-
/*
theStats.AddDownDataOverheadCrypt(nBufLen - nResult);
*/
theApp.pBandWidthControl->AddeMuleInObfuscation(nBufLen - nResult);
//Xman end
return nResult; // done
}
else{
DebugLogWarning(_T("Obfuscated packet expected but magicvalue mismatch on UDP packet from ServerIP: %s"), ipstr(dbgIP));
return nBufLen; // pass through, let the Receivefunction do the errorhandling on this junk
}
}
int CEncryptedDatagramSocket::DecryptReceivedClient(BYTE* pbyBufIn, int nBufLen, BYTE** ppbyBufOut, uint32 dwIP) const{
int nResult = nBufLen;
*ppbyBufOut = pbyBufIn;
if (nResult <= CRYPT_HEADER_WITHOUTPADDING || !thePrefs.IsClientCryptLayerSupported())
return nResult;
switch (pbyBufIn[0]){
case OP_EMULEPROT:
case OP_KADEMLIAPACKEDPROT:
case OP_KADEMLIAHEADER:
case OP_UDPRESERVEDPROT1:
case OP_UDPRESERVEDPROT2:
case OP_PACKEDPROT:
return nResult; // no encrypted packet (see description on top)
}
// might be an encrypted packet, try to decrypt
uchar achKeyData[23];
md4cpy(achKeyData, thePrefs.GetUserHash());
achKeyData[20] = MAGICVALUE_UDP;
memcpy(achKeyData + 16, &dwIP, 4);
memcpy(achKeyData + 21, pbyBufIn + 1, 2); // random key part sent from remote client
MD5Sum md5(achKeyData, sizeof(achKeyData));
RC4_Key_Struct keyReceiveKey;
RC4CreateKey(md5.GetRawHash(), 16, &keyReceiveKey, true);
uint32 dwValue;
RC4Crypt(pbyBufIn + 3, (uchar*)&dwValue, sizeof(dwValue), &keyReceiveKey);
if (dwValue == MAGICVALUE_UDP_SYNC_CLIENT){
// yup this is an encrypted packet
DEBUG_ONLY( DebugLog(_T("Received obfuscated UDP packet from clientIP: %s"), ipstr(dwIP)) );
uint8 byPadLen;
RC4Crypt(pbyBufIn + 7, (uchar*)&byPadLen, 1, &keyReceiveKey);
nResult -= CRYPT_HEADER_WITHOUTPADDING;
if (nResult <= byPadLen){
DebugLogError(_T("Invalid obfuscated UDP packet from clientIP: %s, Paddingsize (%u) larger than received bytes"), ipstr(dwIP), byPadLen);
return nBufLen; // pass through, let the Receivefunction do the errorhandling on this junk
}
if (byPadLen > 0)
RC4Crypt(NULL, NULL, byPadLen, &keyReceiveKey);
nResult -= byPadLen;
*ppbyBufOut = pbyBufIn + (nBufLen - nResult);
RC4Crypt((uchar*)*ppbyBufOut, (uchar*)*ppbyBufOut, nResult, &keyReceiveKey);
theStats.AddDownDataOverheadCrypt(nBufLen - nResult);
return nResult; // done
}
else{
DebugLogWarning(_T("Obfuscated packet expected but magicvalue mismatch on UDP packet from clientIP: %s"), ipstr(dwIP));
return nBufLen; // pass through, let the Receivefunction do the errorhandling on this junk
}
}
void CEncryptedStreamSocket::SetConnectionEncryption(bool bEnabled, const uchar* pTargetClientHash, bool bServerConnection){
if (m_StreamCryptState != ECS_UNKNOWN && m_StreamCryptState != ECS_NONE){
if (!m_StreamCryptState == ECS_NONE || bEnabled)
ASSERT( false );
return;
}
ASSERT( m_pRC4SendKey == NULL );
ASSERT( m_pRC4ReceiveKey == NULL );
if (bEnabled && pTargetClientHash != NULL && !bServerConnection){
m_StreamCryptState = ECS_PENDING;
// create obfuscation keys, see on top for key format
// use the crypt random generator
m_nRandomKeyPart = cryptRandomGen.GenerateWord32();
uchar achKeyData[21];
md4cpy(achKeyData, pTargetClientHash);
memcpy(achKeyData + 17, &m_nRandomKeyPart, 4);
achKeyData[16] = MAGICVALUE_REQUESTER;
MD5Sum md5(achKeyData, sizeof(achKeyData));
m_pRC4SendKey = RC4CreateKey(md5.GetRawHash(), 16, NULL);
achKeyData[16] = MAGICVALUE_SERVER;
md5.Calculate(achKeyData, sizeof(achKeyData));
m_pRC4ReceiveKey = RC4CreateKey(md5.GetRawHash(), 16, NULL);
}
else if (bServerConnection && bEnabled){
m_bServerCrypt = true;
m_StreamCryptState = ECS_PENDING_SERVER;
}
else{
ASSERT( !bEnabled );
m_StreamCryptState = ECS_NONE;
}
}
// 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::DecryptReceivedClient(BYTE* pbyBufIn, int nBufLen, BYTE** ppbyBufOut, uint32 dwIP, uint32* nReceiverVerifyKey, uint32* nSenderVerifyKey) const{
int nResult = nBufLen;
*ppbyBufOut = pbyBufIn;
if (nReceiverVerifyKey == NULL || nSenderVerifyKey == NULL){
ASSERT( false );
return nResult;
}
*nReceiverVerifyKey = 0;
*nSenderVerifyKey = 0;
if (nResult <= CRYPT_HEADER_WITHOUTPADDING /*|| !thePrefs.IsClientCryptLayerSupported()*/)
return nResult;
switch (pbyBufIn[0]){
case OP_EMULEPROT:
case OP_KADEMLIAPACKEDPROT:
case OP_KADEMLIAHEADER:
case OP_UDPRESERVEDPROT1:
case OP_UDPRESERVEDPROT2:
case OP_PACKEDPROT:
return nResult; // no encrypted packet (see description on top)
}
// might be an encrypted packet, try to decrypt
RC4_Key_Struct keyReceiveKey;
uint32 dwValue = 0;
// check the marker bit which type this packet could be and which key to test first, this is only an indicator since old clients have it set random
// see the header for marker bits explanation
byte byCurrentTry = ((pbyBufIn[0] & 0x03) == 3) ? 1 : (pbyBufIn[0] & 0x03);
byte byTries;
if (Kademlia::CKademlia::GetPrefs() == NULL) {
// if kad never run, no point in checking anything except for ed2k encryption
byTries = 1;
byCurrentTry = 1;
}
else
byTries = 3;
bool bKadRecvKeyUsed = false;
bool bKad = false;
do{
byTries--;
MD5Sum md5;
if (byCurrentTry == 0) {
// kad packet with NodeID as key
bKad = true;
bKadRecvKeyUsed = false;
if (Kademlia::CKademlia::GetPrefs()) {
uchar achKeyData[18];
memcpy(achKeyData, Kademlia::CKademlia::GetPrefs()->GetKadID().GetData(), 16);
memcpy(achKeyData + 16, pbyBufIn + 1, 2); // random key part sent from remote client
md5.Calculate(achKeyData, sizeof(achKeyData));
}
}
else if (byCurrentTry == 1) {
// ed2k packet
bKad = false;
bKadRecvKeyUsed = false;
uchar achKeyData[23];
md4cpy(achKeyData, thePrefs.GetUserHash());
achKeyData[20] = MAGICVALUE_UDP;
memcpy(achKeyData + 16, &dwIP, 4);
memcpy(achKeyData + 21, pbyBufIn + 1, 2); // random key part sent from remote client
md5.Calculate(achKeyData, sizeof(achKeyData));
}
else if (byCurrentTry == 2) {
// kad packet with ReceiverKey as key
bKad = true;
bKadRecvKeyUsed = true;
if (Kademlia::CKademlia::GetPrefs()) {
uchar achKeyData[6];
PokeUInt32(achKeyData, Kademlia::CPrefs::GetUDPVerifyKey(dwIP));
memcpy(achKeyData + 4, pbyBufIn + 1, 2); // random key part sent from remote client
md5.Calculate(achKeyData, sizeof(achKeyData));
}
}
else
ASSERT( false );
RC4CreateKey(md5.GetRawHash(), 16, &keyReceiveKey, true);
RC4Crypt(pbyBufIn + 3, (uchar*)&dwValue, sizeof(dwValue), &keyReceiveKey);
byCurrentTry = (byCurrentTry + 1) % 3;
} while (dwValue != MAGICVALUE_UDP_SYNC_CLIENT && byTries > 0); // try to decrypt as ed2k as well as kad packet if needed (max 3 rounds)
if (dwValue == MAGICVALUE_UDP_SYNC_CLIENT){
// yup this is an encrypted packet
// debugoutput notices
// the following cases are "allowed" but shouldn't happen given that there is only our implementation yet
if (bKad && (pbyBufIn[0] & 0x01) != 0)
DebugLog(_T("Received obfuscated UDP packet from clientIP: %s with wrong key marker bits (kad packet, ed2k bit)"), ipstr(dwIP));
else if (bKad && !bKadRecvKeyUsed && (pbyBufIn[0] & 0x02) != 0)
DebugLog(_T("Received obfuscated UDP packet from clientIP: %s with wrong key marker bits (kad packet, nodeid key, recvkey bit)"), ipstr(dwIP));
else if (bKad && bKadRecvKeyUsed && (pbyBufIn[0] & 0x02) == 0)
DebugLog(_T("Received obfuscated UDP packet from clientIP: %s with wrong key marker bits (kad packet, recvkey key, nodeid bit)"), ipstr(dwIP));
uint8 byPadLen;
RC4Crypt(pbyBufIn + 7, (uchar*)&byPadLen, 1, &keyReceiveKey);
nResult -= CRYPT_HEADER_WITHOUTPADDING;
if (nResult <= byPadLen){
DebugLogError(_T("Invalid obfuscated UDP packet from clientIP: %s, Paddingsize (%u) larger than received bytes"), ipstr(dwIP), byPadLen);
return nBufLen; // pass through, let the Receivefunction do the errorhandling on this junk
}
if (byPadLen > 0)
RC4Crypt(NULL, NULL, byPadLen, &keyReceiveKey);
nResult -= byPadLen;
if (bKad){
if (nResult <= 8){
DebugLogError(_T("Obfuscated Kad packet with mismatching size (verify keys missing) received from clientIP: %s"), ipstr(dwIP));
return nBufLen; // pass through, let the Receivefunction do the errorhandling on this junk;
}
// read the verify keys
RC4Crypt(pbyBufIn + CRYPT_HEADER_WITHOUTPADDING + byPadLen, (uchar*)nReceiverVerifyKey, 4, &keyReceiveKey);
RC4Crypt(pbyBufIn + CRYPT_HEADER_WITHOUTPADDING + byPadLen + 4, (uchar*)nSenderVerifyKey, 4, &keyReceiveKey);
nResult -= 8;
}
*ppbyBufOut = pbyBufIn + (nBufLen - nResult);
RC4Crypt((uchar*)*ppbyBufOut, (uchar*)*ppbyBufOut, nResult, &keyReceiveKey);
//Xman
// Maella -Accurate measure of bandwidth: eDonkey data + control, network adapter-
/*
theStats.AddDownDataOverheadCrypt(nBufLen - nResult);
*/
theApp.pBandWidthControl->AddeMuleInObfuscation(nBufLen - nResult);
//Xman end
//DEBUG_ONLY( DebugLog(_T("Received obfuscated UDP packet from clientIP: %s, Key: %s, RKey: %u, SKey: %u"), ipstr(dwIP), bKad ? (bKadRecvKeyUsed ? _T("ReceiverKey") : _T("NodeID")) : _T("UserHash")
// , nReceiverVerifyKey != 0 ? *nReceiverVerifyKey : 0, nSenderVerifyKey != 0 ? *nSenderVerifyKey : 0) );
return nResult; // done
}
else{
DebugLogWarning(_T("Obfuscated packet expected but magicvalue mismatch on UDP packet from clientIP: %s, Possible RecvKey: %u"), ipstr(dwIP), Kademlia::CPrefs::GetUDPVerifyKey(dwIP));
return nBufLen; // pass through, let the Receivefunction do the errorhandling on this junk
}
}
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 CEncryptedDatagramSocket::DecryptReceivedClient(BYTE* pbyBufIn, int nBufLen, BYTE** ppbyBufOut, uint32 dwIP, uint16* nReceiverVerifyKey, uint16* nSenderVerifyKey) const{
int nResult = nBufLen;
*ppbyBufOut = pbyBufIn;
if (nResult <= CRYPT_HEADER_WITHOUTPADDING /*|| !thePrefs.IsClientCryptLayerSupported()*/)
return nResult;
if (nReceiverVerifyKey == NULL || nSenderVerifyKey == NULL){
ASSERT( false );
return nResult;
}
switch (pbyBufIn[0]){
case OP_EMULEPROT:
case OP_KADEMLIAPACKEDPROT:
case OP_KADEMLIAHEADER:
case OP_UDPRESERVEDPROT1:
case OP_UDPRESERVEDPROT2:
case OP_PACKEDPROT:
return nResult; // no encrypted packet (see description on top)
}
bool bKad = (pbyBufIn[0] & 0x01) == 0; // check the marker bit if this is a kad or ed2k packet, this is only an indicator since old clients have it set random
// might be an encrypted packet, try to decrypt
RC4_Key_Struct keyReceiveKey;
uint32 dwValue = 0;
bool bFlipTry = false;
do{
bKad = bFlipTry ? !bKad : bKad;
MD5Sum md5;
if (bKad){
if (Kademlia::CKademlia::GetPrefs()) {
uchar achKeyData[18];
memcpy(achKeyData, Kademlia::CKademlia::GetPrefs()->GetKadID().GetData(), 16);
memcpy(achKeyData + 16, pbyBufIn + 1, 2); // random key part sent from remote client
md5.Calculate(achKeyData, sizeof(achKeyData));
}
}
else{
uchar achKeyData[23];
md4cpy(achKeyData, thePrefs.GetUserHash());
achKeyData[20] = MAGICVALUE_UDP;
memcpy(achKeyData + 16, &dwIP, 4);
memcpy(achKeyData + 21, pbyBufIn + 1, 2); // random key part sent from remote client
md5.Calculate(achKeyData, sizeof(achKeyData));
}
RC4CreateKey(md5.GetRawHash(), 16, &keyReceiveKey, true);
RC4Crypt(pbyBufIn + 3, (uchar*)&dwValue, sizeof(dwValue), &keyReceiveKey);
bFlipTry = !bFlipTry; // next round try the other possibility
} while (dwValue != MAGICVALUE_UDP_SYNC_CLIENT && bFlipTry); // try to decrypt as ed2k as well as kad packet if needed (max 2 rounds)
if (dwValue == MAGICVALUE_UDP_SYNC_CLIENT){
// yup this is an encrypted packet
DEBUG_ONLY( DebugLog(_T("Received obfuscated UDP packet from clientIP: %s"), ipstr(dwIP)) );
uint8 byPadLen;
RC4Crypt(pbyBufIn + 7, (uchar*)&byPadLen, 1, &keyReceiveKey);
nResult -= CRYPT_HEADER_WITHOUTPADDING;
if (nResult <= byPadLen){
DebugLogError(_T("Invalid obfuscated UDP packet from clientIP: %s, Paddingsize (%u) larger than received bytes"), ipstr(dwIP), byPadLen);
return nBufLen; // pass through, let the Receivefunction do the errorhandling on this junk
}
if (byPadLen > 0)
RC4Crypt(NULL, NULL, byPadLen, &keyReceiveKey);
nResult -= byPadLen;
if (bKad){
if (nResult <= 4){
DebugLogError(_T("Obfuscated Kad packet with mismatching size (verify keys missing) received from clientIP: %s"), ipstr(dwIP));
return nBufLen; // pass through, let the Receivefunction do the errorhandling on this junk;
}
// read the verify keys
*nReceiverVerifyKey = PeekUInt16(pbyBufIn + CRYPT_HEADER_WITHOUTPADDING + byPadLen);
*nSenderVerifyKey = PeekUInt16(pbyBufIn + CRYPT_HEADER_WITHOUTPADDING + byPadLen + 2);
nResult -= 4;
}
else{
*nReceiverVerifyKey = 0;
*nSenderVerifyKey = 0;
}
*ppbyBufOut = pbyBufIn + (nBufLen - nResult);
RC4Crypt((uchar*)*ppbyBufOut, (uchar*)*ppbyBufOut, nResult, &keyReceiveKey);
theStats.AddDownDataOverheadCrypt(nBufLen - nResult);
return nResult; // done
}
else{
DebugLogWarning(_T("Obfuscated packet expected but magicvalue mismatch on UDP packet from clientIP: %s"), ipstr(dwIP));
return nBufLen; // pass through, let the Receivefunction do the errorhandling on this junk
}
}
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);
}
}
