clientcredits.cpp

eMule0.44b的原代码

void CClientCreditsList::Process()
{
	if (::GetTickCount() - m_nLastSaved > MIN2MS(13))
		SaveList();
}

void CClientCredits::InitalizeIdent(){
	if (m_pCredits->nKeySize == 0 ){
		memset(m_abyPublicKey,0,80); // for debugging
		m_nPublicKeyLen = 0;
		IdentState = IS_NOTAVAILABLE;
	}
	else{
		m_nPublicKeyLen = m_pCredits->nKeySize;
		memcpy(m_abyPublicKey, m_pCredits->abySecureIdent, m_nPublicKeyLen);
		IdentState = IS_IDNEEDED;
	}
	m_dwCryptRndChallengeFor = 0;
	m_dwCryptRndChallengeFrom = 0;
	m_dwIdentIP = 0;
}

void CClientCredits::Verified(uint32 dwForIP){
	m_dwIdentIP = dwForIP;
	// client was verified, copy the keyto store him if not done already
	if (m_pCredits->nKeySize == 0){
		m_pCredits->nKeySize = m_nPublicKeyLen; 
		memcpy(m_pCredits->abySecureIdent, m_abyPublicKey, m_nPublicKeyLen);
		if (GetDownloadedTotal() > 0){
			// for security reason, we have to delete all prior credits here
			m_pCredits->nDownloadedHi = 0;
			m_pCredits->nDownloadedLo = 1;
			m_pCredits->nUploadedHi = 0;
			m_pCredits->nUploadedLo = 1; // in order to safe this client, set 1 byte
			if (thePrefs.GetVerbose())
				DEBUG_ONLY(AddDebugLogLine(false, _T("Credits deleted due to new SecureIdent")));
		}
	}
	IdentState = IS_IDENTIFIED;
}

bool CClientCredits::SetSecureIdent(uchar* pachIdent, uint8 nIdentLen){ // verified Public key cannot change, use only if there is not public key yet
	if (MAXPUBKEYSIZE < nIdentLen || m_pCredits->nKeySize != 0 )
		return false;
	memcpy(m_abyPublicKey,pachIdent, nIdentLen);
	m_nPublicKeyLen = nIdentLen;
	IdentState = IS_IDNEEDED;
	return true;
}

EIdentState	CClientCredits::GetCurrentIdentState(uint32 dwForIP) const{
	if (IdentState != IS_IDENTIFIED)
		return IdentState;
	else{
		if (dwForIP == m_dwIdentIP)
			return IS_IDENTIFIED;
		else
			return IS_IDBADGUY; 
			// mod note: clients which just reconnected after an IP change and have to ident yet will also have this state for 1-2 seconds
			//		 so don't try to spam such clients with "bad guy" messages (besides: spam messages are always bad)
	}
}

using namespace CryptoPP;

void CClientCreditsList::InitalizeCrypting(){
	m_nMyPublicKeyLen = 0;
	memset(m_abyMyPublicKey,0,80); // not really needed; better for debugging tho
	m_pSignkey = NULL;
	if (!thePrefs.IsSecureIdentEnabled())
		return;
	// check if keyfile is there
	bool bCreateNewKey = false;
	HANDLE hKeyFile = ::CreateFile(thePrefs.GetConfigDir() + CString("cryptkey.dat"), GENERIC_READ, FILE_SHARE_READ, NULL,
										OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
	if (hKeyFile != INVALID_HANDLE_VALUE)
	{
		if (::GetFileSize(hKeyFile, NULL) == 0)
			bCreateNewKey = true;
		::CloseHandle(hKeyFile);
	}
	else
		bCreateNewKey = true;
	if (bCreateNewKey)
		CreateKeyPair();
	
	// load key
	try{
		// load private key
		FileSource filesource(CStringA(thePrefs.GetConfigDir() + _T("cryptkey.dat")), true,new Base64Decoder);
		m_pSignkey = new RSASSA_PKCS1v15_SHA_Signer(filesource);
		// calculate and store public key
		RSASSA_PKCS1v15_SHA_Verifier pubkey(*m_pSignkey);
		ArraySink asink(m_abyMyPublicKey, 80);
		pubkey.DEREncode(asink);
		m_nMyPublicKeyLen = asink.TotalPutLength();
		asink.MessageEnd();
	}
	catch(...)
	{
		if (m_pSignkey){
			delete m_pSignkey;
			m_pSignkey = NULL;
		}
		AddLogLine(false, GetResString(IDS_CRYPT_INITFAILED));
		ASSERT(0);
	}
	//Debug_CheckCrypting();
}

bool CClientCreditsList::CreateKeyPair(){
	try{
		AutoSeededRandomPool rng;
		InvertibleRSAFunction privkey;
		privkey.Initialize(rng,RSAKEYSIZE);

		Base64Encoder privkeysink(new FileSink(CStringA(thePrefs.GetConfigDir() + _T("cryptkey.dat"))));
		privkey.DEREncode(privkeysink);
		privkeysink.MessageEnd();

		if (thePrefs.GetLogSecureIdent())
			AddDebugLogLine(false, _T("Created new RSA keypair"));
	}
	catch(...)
	{
		if (thePrefs.GetVerbose())
			AddDebugLogLine(false, _T("Failed to create new RSA keypair"));
		ASSERT ( false );
		return false;
	}
	return true;
}

uint8 CClientCreditsList::CreateSignature(CClientCredits* pTarget, uchar* pachOutput, uint8 nMaxSize, uint32 ChallengeIP, uint8 byChaIPKind, CryptoPP::RSASSA_PKCS1v15_SHA_Signer* sigkey){
	// sigkey param is used for debug only
	if (sigkey == NULL)
		sigkey = m_pSignkey;

	// create a signature of the public key from pTarget
	ASSERT( pTarget );
	ASSERT( pachOutput );
	uint8 nResult;
	if ( !CryptoAvailable() )
		return 0;
	try{
		
		SecByteBlock sbbSignature(sigkey->SignatureLength());
		AutoSeededRandomPool rng;
		byte abyBuffer[MAXPUBKEYSIZE+9];
		uint32 keylen = pTarget->GetSecIDKeyLen();
		memcpy(abyBuffer,pTarget->GetSecureIdent(),keylen);
		// 4 additional bytes random data send from this client
		uint32 challenge = pTarget->m_dwCryptRndChallengeFrom;
		ASSERT ( challenge != 0 );
		PokeUInt32(abyBuffer+keylen, challenge);
		uint16 ChIpLen = 0;
		if ( byChaIPKind != 0){
			ChIpLen = 5;
			PokeUInt32(abyBuffer+keylen+4, ChallengeIP);
			PokeUInt8(abyBuffer+keylen+4+4, byChaIPKind);
		}
		sigkey->SignMessage(rng, abyBuffer ,keylen+4+ChIpLen , sbbSignature.begin());
		ArraySink asink(pachOutput, nMaxSize);
		asink.Put(sbbSignature.begin(), sbbSignature.size());
		nResult = asink.TotalPutLength();			
	}
	catch(...)
	{
		ASSERT ( false );
		nResult = 0;
	}
	return nResult;
}

bool CClientCreditsList::VerifyIdent(CClientCredits* pTarget, uchar* pachSignature, uint8 nInputSize, uint32 dwForIP, uint8 byChaIPKind){
	ASSERT( pTarget );
	ASSERT( pachSignature );
	if ( !CryptoAvailable() ){
		pTarget->IdentState = IS_NOTAVAILABLE;
		return false;
	}
	bool bResult;
	try{
		StringSource ss_Pubkey((byte*)pTarget->GetSecureIdent(),pTarget->GetSecIDKeyLen(),true,0);
		RSASSA_PKCS1v15_SHA_Verifier pubkey(ss_Pubkey);
		// 4 additional bytes random data send from this client +5 bytes v2
		byte abyBuffer[MAXPUBKEYSIZE+9];
		memcpy(abyBuffer,m_abyMyPublicKey,m_nMyPublicKeyLen);
		uint32 challenge = pTarget->m_dwCryptRndChallengeFor;
		ASSERT ( challenge != 0 );
		PokeUInt32(abyBuffer+m_nMyPublicKeyLen, challenge);
		
		// v2 security improvments (not supported by 29b, not used as default by 29c)
		uint8 nChIpSize = 0;
		if (byChaIPKind != 0){
			nChIpSize = 5;
			uint32 ChallengeIP = 0;
			switch (byChaIPKind){
				case CRYPT_CIP_LOCALCLIENT:
					ChallengeIP = dwForIP;
					break;
				case CRYPT_CIP_REMOTECLIENT:
					if (theApp.serverconnect->GetClientID() == 0 || theApp.serverconnect->IsLowID()){
						if (thePrefs.GetLogSecureIdent())
							AddDebugLogLine(false, _T("Warning: Maybe SecureHash Ident fails because LocalIP is unknown"));
						ChallengeIP = theApp.serverconnect->GetLocalIP();
					}
					else
						ChallengeIP = theApp.serverconnect->GetClientID();
					break;
				case CRYPT_CIP_NONECLIENT: // maybe not supported in future versions
					ChallengeIP = 0;
					break;
			}
			PokeUInt32(abyBuffer+m_nMyPublicKeyLen+4, ChallengeIP);
			PokeUInt8(abyBuffer+m_nMyPublicKeyLen+4+4, byChaIPKind);
		}
		//v2 end

		bResult = pubkey.VerifyMessage(abyBuffer, m_nMyPublicKeyLen+4+nChIpSize, pachSignature, nInputSize);
	}
	catch(...)
	{
		if (thePrefs.GetVerbose())
			AddDebugLogLine(false, _T("Error: Unknown exception in %hs"), __FUNCTION__);
		//ASSERT(0);
		bResult = false;
	}
	if (!bResult){
		if (pTarget->IdentState == IS_IDNEEDED)
			pTarget->IdentState = IS_IDFAILED;
	}
	else{
		pTarget->Verified(dwForIP);
	}
	return bResult;
}

bool CClientCreditsList::CryptoAvailable(){
	return (m_nMyPublicKeyLen > 0 && m_pSignkey != 0 && thePrefs.IsSecureIdentEnabled() );
}


#ifdef _DEBUG
bool CClientCreditsList::Debug_CheckCrypting(){
	// create random key
	AutoSeededRandomPool rng;

	RSASSA_PKCS1v15_SHA_Signer priv(rng, 384);
	RSASSA_PKCS1v15_SHA_Verifier pub(priv);

	byte abyPublicKey[80];
	ArraySink asink(abyPublicKey, 80);
	pub.DEREncode(asink);
	uint8 PublicKeyLen = asink.TotalPutLength();
	asink.MessageEnd();
	uint32 challenge = rand();
	// create fake client which pretends to be this emule
	CreditStruct* newcstruct = new CreditStruct;
	memset(newcstruct, 0, sizeof(CreditStruct));
	CClientCredits* newcredits = new CClientCredits(newcstruct);
	newcredits->SetSecureIdent(m_abyMyPublicKey,m_nMyPublicKeyLen);
	newcredits->m_dwCryptRndChallengeFrom = challenge;
	// create signature with fake priv key
	uchar pachSignature[200];
	memset(pachSignature,200,0);
	uint8 sigsize = CreateSignature(newcredits,pachSignature,200,0,false, &priv);


	// next fake client uses the random created public key
	CreditStruct* newcstruct2 = new CreditStruct;
	memset(newcstruct2, 0, sizeof(CreditStruct));
	CClientCredits* newcredits2 = new CClientCredits(newcstruct2);
	newcredits2->m_dwCryptRndChallengeFor = challenge;

	// if you uncomment one of the following lines the check has to fail
	//abyPublicKey[5] = 34;
	//m_abyMyPublicKey[5] = 22;
	//pachSignature[5] = 232;

	newcredits2->SetSecureIdent(abyPublicKey,PublicKeyLen);

	//now verify this signature - if it's true everything is fine
	bool bResult = VerifyIdent(newcredits2,pachSignature,sigsize,0,0);

	delete newcredits;
	delete newcredits2;

	return bResult;
}
#endif

uint32 CClientCredits::GetSecureWaitStartTime(uint32 dwForIP){
	if (m_dwUnSecureWaitTime == 0 || m_dwSecureWaitTime == 0)
		SetSecWaitStartTime(dwForIP);

	if (m_pCredits->nKeySize != 0){	// this client is a SecureHash Client
		if (GetCurrentIdentState(dwForIP) == IS_IDENTIFIED){ // good boy
			return m_dwSecureWaitTime;
		}
		else{	// not so good boy
			if (dwForIP == m_dwWaitTimeIP){
				return m_dwUnSecureWaitTime;
			}
			else{	// bad boy
				// this can also happen if the client has not identified himself yet, but will do later - so maybe he is not a bad boy :) .
				CString buffer2, buffer;
				/*for (uint16 i = 0;i != 16;i++){
					buffer2.Format("%02X",this->m_pCredits->abyKey[i]);
					buffer+=buffer2;
				}
				if (thePrefs.GetLogSecureIdent())
					AddDebugLogLine(false,"Warning: WaitTime resetted due to Invalid Ident for Userhash %s",buffer.GetBuffer());*/
				
				m_dwUnSecureWaitTime = ::GetTickCount();
				m_dwWaitTimeIP = dwForIP;
				return m_dwUnSecureWaitTime;
			}	
		}
	}
	else{	// not a SecureHash Client - handle it like before for now (no security checks)
		return m_dwUnSecureWaitTime;
	}
}

void CClientCredits::SetSecWaitStartTime(uint32 dwForIP){
	m_dwUnSecureWaitTime = ::GetTickCount()-1;
	m_dwSecureWaitTime = ::GetTickCount()-1;
	m_dwWaitTimeIP = dwForIP;
}

void CClientCredits::ClearWaitStartTime(){
	m_dwUnSecureWaitTime = 0;
	m_dwSecureWaitTime = 0;
}