/*

* Copyright (c) 2008-2009 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the License "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description: 

* Software Mac Implementation

* plugin-dll headers

*

*/

/**

 @file

*/

#include "cmacimpl.h"

#include "pluginconfig.h"

#include <cryptospi/cryptomacapi.h>

using namespace SoftwareCrypto;

using namespace CryptoSpi;

/**

 * Constants used to generate Key1, Key2 and Key3

 */

const TUint8 K1Constant[] = {0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01};

const TUint8 K2Constant[] = {0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02};

const TUint8 K3Constant[] = {0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03};

const TInt KAesXcbcMac96Size = 12;

CCMacImpl* CCMacImpl::NewL(const CKey& aKey, CSymmetricCipher* aSymmetricCipher, TInt32 aAlgorithmUid)

	{

	CCMacImpl* self = CCMacImpl::NewLC(aKey, aSymmetricCipher, aAlgorithmUid);

	CleanupStack::Pop(self);

	return self;

	}

CCMacImpl* CCMacImpl::NewLC(const CKey& aKey, CSymmetricCipher* aSymmetricCipher, TInt32 aAlgorithmUid)

	{

	CCMacImpl* self = NULL;

 	TRAPD(err, self = new (ELeave) CCMacImpl(aSymmetricCipher));

  	if(err!=KErrNone)

  		{

  		delete aSymmetricCipher;

  		User::Leave(err);

  		}

	CleanupStack::PushL(self);

	self->ConstructL(aKey, aAlgorithmUid);

	return self;

	}

CKey* CCMacImpl::Create128bitKeyL(const CKey& aKey)

	{

	TBuf8<KMacBlockSize> keybuffer;

	CryptoSpi::CKey* key = NULL;

	const TDesC8& keyContent=aKey.GetTDesC8L(CryptoSpi::KSymmetricKeyParameterUid);

	if( (TUint32)keyContent.Size() > KMacBlockSize)

		{

		// Create key

		CryptoSpi::CCryptoParams* keyParams = CryptoSpi::CCryptoParams::NewLC();

		keybuffer.SetLength(KMacBlockSize);

		keybuffer.FillZ();

		// 'keybuffer' is the key with 128 zero bits.

		keyParams->AddL(keybuffer, CryptoSpi::KSymmetricKeyParameterUid);

		key=CryptoSpi::CKey::NewLC(aKey.KeyProperty(),*keyParams);

		// evaluate final key data.

		SetKeyL(*key);

		CleanupStack::PopAndDestroy(2, keyParams);

		keybuffer.Copy(FinalL(keyContent));

		// 'keybuffer' contains the final key data.

		}

	else 

		{

		keybuffer.Copy(keyContent);

		TUint i;

		for (i=keybuffer.Size();i<KMacBlockSize;++i)

			{

			keybuffer.Append(0);

			}

		// 'keybuffer' contains the final key data.

		}

	// create a new CKey instance and assign it to iKey using 'keybuffer'.

	CryptoSpi::CCryptoParams* keyParams = CryptoSpi::CCryptoParams::NewLC();

	keyParams->AddL(keybuffer, CryptoSpi::KSymmetricKeyParameterUid);

	key=CryptoSpi::CKey::NewL(aKey.KeyProperty(),*keyParams);

	CleanupStack::PopAndDestroy(keyParams);	

	// 'key' will contain the final CKey instance.

	return key;

	}

void CCMacImpl::SetKeyL(const CKey& aKey)

	{

	const TPtrC8 KeyConstant1(K1Constant, KMacBlockSize);

	const TPtrC8 KeyConstant2(K2Constant, KMacBlockSize);

	const TPtrC8 KeyConstant3(K3Constant, KMacBlockSize);

	// Initialize the cipher class to encrypt Keyconstants to generate additional keys.

	if (iImplementationUid == CryptoSpi::KAlgorithmCipherAesXcbcPrf128)

		{

		// RFC 4434: keys that were not equal in length to 128 bits will no longer be

		// rejected but instead will be made 128 bits for AES-XCBC-PRF-128 Algorithm only.

		CryptoSpi::CKey* key = Create128bitKeyL(aKey);

		CleanupStack::PushL(key);

		iCipherImpl->SetKeyL(*key);

		CleanupStack::PopAndDestroy(key);	

		}

	else

		{

		iCipherImpl->SetKeyL(aKey);

		}

	iCipherImpl->SetCryptoModeL(CryptoSpi::KCryptoModeEncryptUid);

	iCipherImpl->SetOperationModeL(CryptoSpi::KOperationModeNoneUid);

	// cipher class expects the output buffer to be empty.

	iKey1.Zero();

	iKey2.Zero();

	iKey3.Zero();

	// aKey is used to generate Key1, Key2 and Key3.

	// Where Key1 = encrypt KeyConstant1 with aKey

	// Where Key2 = encrypt KeyConstant2 with aKey

	// Where Key3 = encrypt KeyConstant3 with aKey

	// Key1 is used to encrypt the data whereas

	// Key2 and Key3 is used to XOR with the last 

	// block.

    iCipherImpl->ProcessFinalL(KeyConstant1, iKey1);

	iCipherImpl->ProcessFinalL(KeyConstant2, iKey2);

	iCipherImpl->ProcessFinalL(KeyConstant3, iKey3);

	// Create CKey instance with key1

	CCryptoParams* keyParam =CCryptoParams::NewLC();

 	keyParam->AddL(iKey1, CryptoSpi::KSymmetricKeyParameterUid);

 	delete iKey;

 	iKey = NULL;

 	iKey=CKey::NewL(aKey.KeyProperty(), *keyParam);

 	// Initialize the cipher class for MAC calculation.

	iCipherImpl->SetKeyL(*iKey);

 	iCipherImpl->SetOperationModeL(CryptoSpi::KOperationModeCBCUid);

 	Mem::FillZ(iE, sizeof(iE));

 	iCipherImpl->SetIvL(TPtrC8(iE, KMacBlockSize));

 	CleanupStack::PopAndDestroy(keyParam);

	}

CCMacImpl::~CCMacImpl()

	{

	delete iKey;

	delete iCipherImpl;

	}

CCMacImpl::CCMacImpl(const CCMacImpl& aCCMacImpl)

	{

	iImplementationUid = aCCMacImpl.iImplementationUid;

	iKey1.Copy(aCCMacImpl.iKey1);

	iKey2.Copy(aCCMacImpl.iKey2);

	iKey3.Copy(aCCMacImpl.iKey3);

	(void)Mem::Copy(iE, aCCMacImpl.iE, sizeof(iE));

	(void)Mem::Copy(iData, aCCMacImpl.iData, sizeof(iData));

	iCurrentTotalLength = aCCMacImpl.iCurrentTotalLength;

	}

const CExtendedCharacteristics* CCMacImpl::GetExtendedCharacteristicsL()

	{

	return iCipherImpl->GetExtendedCharacteristicsL();

	}

CCMacImpl::CCMacImpl(CryptoSpi::CSymmetricCipher* aSymmetricCipher)

	{

	iCipherImpl = aSymmetricCipher;

	aSymmetricCipher = NULL;

	iMacValue.SetLength(KMacBlockSize);

	}

void CCMacImpl::ConstructL(const CKey& aKey, TInt32 aAlgorithmUid) 

	{

	iImplementationUid = aAlgorithmUid;

    switch(aAlgorithmUid)

    	{

    	case CryptoSpi::KAlgorithmCipherAesXcbcMac96:

    	case CryptoSpi::KAlgorithmCipherAesXcbcPrf128:

    		{

    		SetKeyL(aKey);

     		break;

    		}

    	default:

    		{

    		User::Leave(KErrNotSupported);

    		}

    	}

	}

/**

 * Takes the message and XOR it with iData.

 * 

 * @param aKey 128bit key. This key will be XORed with iData.

 * @param aOutput  The result of the XOR operation will be copied to this.

 * 				   Its length should be 128bit (16bytes).

 */

void CCMacImpl::XORKeyWithData(const TDesC8& aKey, TDes8& aOutput)

	{

	for (TInt i = 0; i < KMacBlockSize; ++i)

		{

		aOutput[i] = iData[i] ^ aKey[i];

		}

	}

/**

 * This function is used to pad message M to make the total message

 * length multiple of block size (128bit). The last block M[n] will be 

 * padded with a single "1" bit followed by the number of "0" bits required

 * to increase M[n]'s size to 128 bits (Block Size).

 * 

 * Used in AES-XCBC-MAC-96 and AES-XCBC-PRF-128 Mac algorithms.

 */

void CCMacImpl::PadMessage()

	{

	if(iCurrentTotalLength < KMacBlockSize)

		{

		iData[iCurrentTotalLength] = 0x80;

		Mem::FillZ(iData + iCurrentTotalLength+1, KMacBlockSize - iCurrentTotalLength - 1);

		}

	}

void CCMacImpl::Reset()

	{

	Mem::FillZ(iE,sizeof(iE));

	iCurrentTotalLength =0;

	// record for Reset, for the next time MacL, UpdateL or FinalL is called as we

	// cannot leave in Reset.

	TRAP(iDelayedReset, iCipherImpl->SetIvL(TPtrC8(iE, KMacBlockSize)));

	}

TPtrC8 CCMacImpl::MacL(const TDesC8& aMessage)

	{

	// Reset the cipher with iE as 128 zero bits as it leaved in previous call to Reset. 

	if (iDelayedReset != KErrNone)

		{

		// iE was reset to 128 zero bits in previous call to Reset which leaved.

		iCipherImpl->SetIvL(TPtrC8(iE, KMacBlockSize));

		iDelayedReset = KErrNone; 

		}

	if (aMessage!=KNullDesC8())

		{

		DoUpdateL(aMessage);			

		}

	// Calculate MAC

	TPtrC8 macPtr(KNullDesC8());

	macPtr.Set(DoFinalL());

	// Restore the internal state.

	// We don't want to save any state change happened in 

	// DoFinalL.

	// iE is not updated in DoFinalL function and hence

	// can be used to reset iCipherImpl to previous state.

	iCipherImpl->SetIvL(TPtrC8(iE, KMacBlockSize));

	return macPtr;		

	}

TPtrC8 CCMacImpl::FinalL(const TDesC8& aMessage)

	{

	// Reset the cipher with iE as 128 zero bits as it leaved in previous call to Reset. 

	if (iDelayedReset == KErrNone)

		{

		// iE was reset to 128 zero bits in previous call to Reset which leaved.

		iCipherImpl->SetIvL(TPtrC8(iE, KMacBlockSize));

		iDelayedReset = KErrNone;

		}

	if (aMessage!=KNullDesC8())

		{

		DoUpdateL(aMessage);			

		}

	TPtrC8 macPtr(KNullDesC8());

	macPtr.Set(DoFinalL());

	Reset();

	return macPtr;

	}

void CCMacImpl::UpdateL(const TDesC8& aMessage)

	{

	// Reset the cipher with iE as 128 zero bits as it leaved in previous call to Reset. 

	if (iDelayedReset == KErrNone)

		{

		// iE was reset to 128 zero bits in previous call to Reset which leaved.

		iCipherImpl->SetIvL(TPtrC8(iE, KMacBlockSize));

		iDelayedReset = KErrNone;

		}

	if (aMessage!=KNullDesC8())

		{

		DoUpdateL(aMessage);			

		}

	}

void CCMacImpl::ProcessBlockL()

	{

	TPtrC8 dataPtr(iData, KMacBlockSize);

	TPtr8 intermediateCipherPtr(iE,0,KMacBlockSize);

	// iData (Block) should be XORed with iE calculated

	// from previoue processing. If it's the first processing

	// then iE will be zero.

	// Here we are not doing explicit XORing because iCpherImpl 

	// is set in CBC mode. Therefore this operation will be

	// done by iCipherImpl

	iCipherImpl->ProcessL(dataPtr, intermediateCipherPtr);

	// After processing discard the block.

	iCurrentTotalLength = 0;

	}

void CCMacImpl::DoUpdateL(const TDesC8& aMessage)

	{

	TInt curLength = aMessage.Length();

	const TUint8* msgPtr = aMessage.Ptr();

	while(curLength > 0)

		{

		// If block is formed then process it.

		if(iCurrentTotalLength == KMacBlockSize)

			ProcessBlockL();

		// Check the space left in the block.

		TUint remainingLength = KMacBlockSize - iCurrentTotalLength;

		// If unprocesed message length is less then remainingLength

		// then copy the entire data to iData else copy till iData

		// if full.

		TUint length = Min(curLength, remainingLength);

		// Discard the return value obtained from Mem::Copy( ) function.		

		(void)Mem::Copy(iData+iCurrentTotalLength, msgPtr, length);

		// Update data offset

		iCurrentTotalLength += length;

		curLength -= length;

		msgPtr += length;

		}

 	}

TPtrC8 CCMacImpl::DoFinalL()

	{

	TBuf8<KMacBlockSize> finalBlock;

	finalBlock.SetLength(KMacBlockSize);

	// If padding is required then use Key3

	// else use Key2.

	if(iCurrentTotalLength < KMacBlockSize)

		{

		PadMessage();

		XORKeyWithData(iKey3, finalBlock);

		}

	else

		{

		XORKeyWithData(iKey2, finalBlock);

		}

	// cipher class expects the output buffer to be empty.

	iMacValue.Zero();

	iCipherImpl->ProcessFinalL(finalBlock, iMacValue);

    return (iImplementationUid == CryptoSpi::KAlgorithmCipherAesXcbcMac96)? iMacValue.Left(KAesXcbcMac96Size): TPtrC8(iMacValue);

	}

void CCMacImpl::ReInitialiseAndSetKeyL(const CKey& aKey)

	{

	Reset();

	SetKeyL(aKey);

	}

CCMacImpl* CCMacImpl::CopyL()

	{

	CCMacImpl* clone = new(ELeave) CCMacImpl(*this);

	CleanupStack::PushL(clone);

	clone->iKey = CKey::NewL(*iKey);

	CryptoSpi::CSymmetricCipherFactory::CreateSymmetricCipherL(clone->iCipherImpl,

												CryptoSpi::KAesUid,

												*iKey,

												CryptoSpi::KCryptoModeEncryptUid,

												CryptoSpi::KOperationModeCBCUid,

												CryptoSpi::KPaddingModeNoneUid,

												NULL);

	clone->iCipherImpl->SetIvL(TPtrC8(clone->iE, KMacBlockSize));

	CleanupStack::Pop();

	return clone;	

	}

CCMacImpl* CCMacImpl::ReplicateL()

	{

	CCMacImpl* replica = CopyL();

	replica->Reset();

	return replica;

	}