/*

 * Copyright (c) 2007-2010 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: 

 *

 */

 #include "symmetriccipherimpl.h"

 #include <e32def.h>

 #include <cryptostrength.h>

 #include <cryptospi/cryptospidef.h>

 #include <cryptospi/keys.h>

 #include <cryptospi/plugincharacteristics.h>

 #include "pluginconfig.h"

 #include <cryptopanic.h>

 #include <securityerr.h>

 #include "../../../source/common/inlines.h"

 using namespace SoftwareCrypto;

 //

 // Implementation of Symmetric Cipher class

 //

 CSymmetricCipherImpl::CSymmetricCipherImpl() 

 	{

 	}

 void CSymmetricCipherImpl::ConstructL(const CKey& aKey) 

 	{

 	DoSetKeyL(aKey);

 	}

 void CSymmetricCipherImpl::SecureDelete(HBufC8*& aBuffer)

 	{

 	if (aBuffer)

 		{

 		aBuffer->Des().FillZ();

 		}

 	delete aBuffer;

 	aBuffer = 0;	

 	}

 CSymmetricCipherImpl::~CSymmetricCipherImpl()

 	{			

 	SecureDelete(iKey);

 	}

 void CSymmetricCipherImpl::Close()

 	{

 	delete this;

 	}

 TAny* CSymmetricCipherImpl::GetExtension(TUid /*aExtensionId*/) 

 	{

 	return 0;

 	}

 void CSymmetricCipherImpl::GetCharacteristicsL(const TAny*& aPluginCharacteristics)

 	{

 	TInt numCiphers = sizeof(KSymmetricCipherCharacteristics)/sizeof(TSymmetricCipherCharacteristics*);

 	TInt32 implUid = ImplementationUid().iUid;

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

 		{

 		if (KSymmetricCipherCharacteristics[i]->cmn.iImplementationUID == implUid)

 			{

 			aPluginCharacteristics = KSymmetricCipherCharacteristics[i];

 			break;

 			}

 		}	

 	}

 TInt CSymmetricCipherImpl::GetKeyStrength() const

 	{

 	return BytesToBits(iKey->Length());

 	}

 HBufC8* CSymmetricCipherImpl::ExtractKeyDataLC(const CKey& aKey) const

 	{

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

 	return keyContent.AllocLC();

 	}

 TInt CSymmetricCipherImpl::KeySize() const

 	{

 	// return key size in BITS

 	return BytesToBits(iKeyBytes);

 	}

 void CSymmetricCipherImpl::DoSetKeyL(const CKey& aKey)

 	{

 	HBufC8* key = ExtractKeyDataLC(aKey);

 	TInt keyLength(key->Length());

 	TCrypto::IsSymmetricWeakEnoughL(BytesToBits(keyLength));

 	if (! IsValidKeyLength(keyLength))

 		{

 		CleanupStack::PopAndDestroy(key);

 		User::Leave(KErrNotSupported);

 		}

 	SecureDelete(iKey);	

 	CleanupStack::Pop(key);

 	iKey = key;

 	iKeyBytes = keyLength;

 	}	

 //

 // Implementation of Symmetric Stream Cipher

 //

 CSymmetricStreamCipherImpl::CSymmetricStreamCipherImpl()

 	{

 	}

 CSymmetricStreamCipherImpl::~CSymmetricStreamCipherImpl()

 	{

 	}

 void CSymmetricStreamCipherImpl::SetKeyL(const CKey& aKey)

 	{

 	DoSetKeyL(aKey);

 	TCrypto::IsSymmetricWeakEnoughL(GetKeyStrength());

 	Reset();

 	}	

 void CSymmetricStreamCipherImpl::ConstructL(const CKey& aKey) 

 	{

 	CSymmetricCipherImpl::ConstructL(aKey);

 	}

 TInt CSymmetricStreamCipherImpl::BlockSize() const

 	{

 	// return block size in BITS

 	return 8;

 	}

 void CSymmetricStreamCipherImpl::SetOperationModeL(TUid /*aOperationMode*/)

 	{

 	User::Leave(KErrNotSupported);

 	}

 void CSymmetricStreamCipherImpl::SetCryptoModeL(TUid /*aCryptoMode*/)

 	{

 	// Call the reset method.

 	Reset();

 	}

 void CSymmetricStreamCipherImpl::SetPaddingModeL(TUid /*aPaddingMode*/)

 	{

 	User::Leave(KErrNotSupported);

 	}

 void CSymmetricStreamCipherImpl::SetIvL(const TDesC8& /*aIv*/)

 	{

 	User::Leave(KErrNotSupported);

 	}

 TInt CSymmetricStreamCipherImpl::MaxOutputLength(TInt aInputLength) const

 	{

 	return aInputLength;	

 	}

 TInt CSymmetricStreamCipherImpl::MaxFinalOutputLength(TInt aInputLength) const

 	{

 	return aInputLength;	

 	}

 void CSymmetricStreamCipherImpl::ProcessL(const TDesC8& aInput, TDes8& aOutput)

 	{

 	TInt outputIndex = aOutput.Size();

 	// aOutput may already have outputIndex bytes of data in it

 	// check there will still be enough space to process the result

 	__ASSERT_DEBUG(aOutput.MaxLength() - outputIndex >= MaxOutputLength(aInput.Length()), User::Panic(KCryptoPanic, ECryptoPanicOutputDescriptorOverflow));

 	aOutput.Append(aInput);

 	TPtr8 transformBuf((TUint8*)(aOutput.Ptr()) + outputIndex, aInput.Size(),

 		aInput.Size());

 	DoProcess(transformBuf);

 	}

 void CSymmetricStreamCipherImpl::ProcessFinalL(const TDesC8& aInput, TDes8& aOutput)

 	{

 	ProcessL(aInput, aOutput);	

 	}

 //

 // Implementation of Symmetric Block Cipher

 //

 CSymmetricBlockCipherImpl::CSymmetricBlockCipherImpl(

 	TUint8 aBlockBytes,

 	TUid aCryptoMode,

 	TUid aOperationMode,

 	TUid aPaddingMode) :

 	iBlockBytes(aBlockBytes),

 	iCryptoMode(aCryptoMode),

 	iOperationMode(aOperationMode),

 	iPaddingMode(aPaddingMode)

 	{

 	}

 CSymmetricBlockCipherImpl::~CSymmetricBlockCipherImpl()

 	{			

 	delete iPadding;

 	delete iCbcRegister;

 	delete iCurrentCipherText;

 	iIv.Close();

 	iInputStore.Close();

 	iPaddingBlock.Close();	

 	}

 void CSymmetricBlockCipherImpl::ConstructL(const CKey& aKey) 

 	{

 	CSymmetricCipherImpl::ConstructL(aKey);

 	DoSetOperationModeL(iOperationMode);

 	DoSetCryptoModeL(iCryptoMode);	

 	DoSetPaddingModeL(iPaddingMode);

 	iInputStore.ReAllocL(iBlockBytes);

 	iPaddingBlock.ReAllocL(iBlockBytes);

 	iCbcRegister = new(ELeave) TUint32[iBlockBytes/4];	

 	iCbcRegisterPtr = reinterpret_cast<TUint8*>(iCbcRegister);

 	iCurrentCipherText = new(ELeave) TUint32[iBlockBytes/4];	

 	iCurrentCipherTextPtr = reinterpret_cast<TUint8*>(iCurrentCipherText);

 	}

 void CSymmetricBlockCipherImpl::Reset()

 	{

 	iInputStore.Zero();

 	iPaddingBlock.Zero();

 	if (iOperationMode.iUid == KOperationModeCBC)

 		{

 		// only copy the IV if it is already set

 		if (iIv.MaxLength() > 0)

 			{

 			Mem::Copy(iCbcRegisterPtr, &iIv[0], iBlockBytes);

 			}

 		}

 	}	

 void CSymmetricBlockCipherImpl::SetKeyL(const CKey& aKey)

 	{

 	DoSetKeyL(aKey);

 	TCrypto::IsSymmetricWeakEnoughL(GetKeyStrength());

 	SetKeySchedule();

 	Reset();

 	}

 void CSymmetricBlockCipherImpl::SetOperationModeL(TUid aOperationMode)

 	{

 	DoSetOperationModeL(aOperationMode);

 	Reset();

 	}

 void CSymmetricBlockCipherImpl::SetCryptoModeL(TUid aCryptoMode)

 	{

 	DoSetCryptoModeL(aCryptoMode);

 	SetKeySchedule();

 	Reset();

 	}

 void CSymmetricBlockCipherImpl::SetPaddingModeL(TUid aPaddingMode)

 	{

 	DoSetPaddingModeL(aPaddingMode);

 	Reset();

 	}

 void CSymmetricBlockCipherImpl::SetIvL(const TDesC8& aIv)

 	{

 	if (iOperationMode.iUid != KOperationModeCBC)

 		{

 		User::Leave(KErrNotSupported);

 		}

 	DoSetIvL(aIv);

 	Reset();

 	}

 void CSymmetricBlockCipherImpl::DoSetOperationModeL(TUid aOperationMode)

 	{

 	switch (aOperationMode.iUid)

 		{

 		case KOperationModeNone:

 		case KOperationModeECB:

 		case KOperationModeCBC:

 			break;

 		default:

 			User::Leave(KErrNotSupported);

 		}

 	iOperationMode = aOperationMode;		

 	}

 void CSymmetricBlockCipherImpl::DoSetCryptoModeL(TUid aCryptoMode)

 	{

 	switch (aCryptoMode.iUid)

 		{

 		case KCryptoModeEncrypt:

 		case KCryptoModeDecrypt:

 			break;

 		default:

 			User::Leave(KErrNotSupported);

 		}

 	iCryptoMode = aCryptoMode;		

 	}

 void CSymmetricBlockCipherImpl::DoSetPaddingModeL(TUid aPaddingMode)

 	{	

 	CPadding* padding(0);	

 	switch (aPaddingMode.iUid)

 		{

 		case KPaddingModeNone:

 			padding = CPaddingNone::NewL(iBlockBytes);

 		break;

 		case KPaddingModeSSLv3:

 			padding = CPaddingSSLv3::NewL(iBlockBytes);

 		break;

 		case KPaddingModePKCS7:

 			padding = CPaddingPKCS7::NewL(iBlockBytes);

 		break;

 		default:

 			User::Leave(KErrNotSupported);

 		}

 	delete iPadding;

 	iPadding = padding;

 	iPaddingMode = aPaddingMode;	

 	}	

 void CSymmetricBlockCipherImpl::DoSetIvL(const TDesC8& aIv)

 	{

 	iIv.ReAllocL(iBlockBytes);

 	iIv.SetLength(iBlockBytes);

 	iIv.Zero();

 	if (aIv.Length() != iBlockBytes) 

 		{

 		User::Leave(KErrArgument);

 		}

 	iIv = aIv;	

 	}	

 TInt CSymmetricBlockCipherImpl::BlockSize() const

 	{

 	// return block size in BITS

 	return BytesToBits(iBlockBytes);

 	}

 TInt CSymmetricBlockCipherImpl::MaxOutputLength(TInt aInputLength) const

 	{	

 	// The maximum output length required for Process is equal to the

 	// size of the number of whole input blocks available.

 	//

 	// The block bytes is a power of two so we can use this to avoid

 	// doing a real mod operation

 	TUint inputStoreLength(iInputStore.Length());

 	TInt rem = (aInputLength + inputStoreLength) & (iBlockBytes - 1);

 	return (aInputLength + inputStoreLength - rem);

 	}	

 TInt CSymmetricBlockCipherImpl::MaxFinalOutputLength(TInt aInputLength) const

 	{

 	if (iCryptoMode.iUid == KCryptoModeEncrypt)

 		{

 		return iPadding->MaxPaddedLength(iInputStore.Length() + aInputLength);

 		}

 	else

 		{

 		return iPadding->MaxUnPaddedLength(aInputLength + iInputStore.Size());

 		}

 	}

 void CSymmetricBlockCipherImpl::ProcessL(const TDesC8& aInput, TDes8& aOutput)

 	{

 	// if we're running in CBC mode then we must have an IV set before we can 

 	// do any processing ie call SetIvL() before this method

 	if (iOperationMode.iUid == KOperationModeCBC)

 		{

 		if (iIv.MaxLength() == 0)

 			{

 			User::Leave(KErrNotSupported);

 			}

 		}

 	TInt inputLength(aInput.Length());	

 	TInt inputStoreLength(iInputStore.Length());

 	if (MaxOutputLength(inputLength) > aOutput.MaxLength())

 		{

 		User::Leave(KErrOverflow);

 		}	

 	TUint8 blockSizeLog = CryptoLog2(iBlockBytes);

 	TInt wholeBlocks = (inputLength + inputStoreLength) >> blockSizeLog; 

 	TInt wholeBlocksSize = wholeBlocks << blockSizeLog;

 	if (wholeBlocks)

 		{

 		TInt outputLength(aOutput.Length());

 		if (inputStoreLength > 0)

 			{

 			aOutput.Append(iInputStore);

 			iInputStore.Zero();

 			}

 		aOutput.Append(aInput.Left(wholeBlocksSize - inputStoreLength));

 		Transform(const_cast<TUint8*>(aOutput.Ptr()) + outputLength, wholeBlocks);

 		}

 	TInt remainingBytes = inputLength + inputStoreLength - wholeBlocksSize;

 	if (remainingBytes > 0)

 		{		

 		iInputStore.Append(aInput.Right(remainingBytes));

 		}

 	}

 void CSymmetricBlockCipherImpl::ProcessFinalL(const TDesC8& aInput, TDes8& aOutput)

 	{	

 	// if we're running in CBC mode then we must have an IV set before we can 

 	// do any processing ie call SetIvL() before this method

 	if (iOperationMode.iUid == KOperationModeCBC)

 		{

 		if (iIv.MaxLength() == 0)

 			{

 			User::Leave(KErrNotSupported);

 			}

 		}

 	if (iCryptoMode.iUid == KCryptoModeEncrypt)

 		{

 		return DoProcessFinalEncryptL(aInput, aOutput);

 		}

 	else

 		{

 		return DoProcessFinalDecryptL(aInput, aOutput);

 		}

 	}

 void CSymmetricBlockCipherImpl::DoProcessFinalEncryptL(const TDesC8& aInput, TDes8& aOutput)

 	{	

 	if (MaxFinalOutputLength(aInput.Length()) > aOutput.MaxLength() - aOutput.Length())

 		{

 		User::Leave(KErrOverflow);

 		}

 	// process everything up to the last (possibly empty block)

 	TInt outputStartIndex = aOutput.Length();

 	ProcessL(aInput, aOutput);

 	// pad the plaintext

 	iPadding->PadL(iInputStore, iPaddingBlock);

 	// if padding required

 	if (iPaddingBlock.Length() > 0)

 		{

 		iInputStore.Zero();

 		// make sure the output is a multiple of the block size

 		User::LeaveIfError(((aOutput.Length() - outputStartIndex + iPaddingBlock.Length()) % iBlockBytes) == 0 ? KErrNone : KErrInvalidPadding);

 		outputStartIndex = aOutput.Length();

 		aOutput.Append(iPaddingBlock);

 		iPaddingBlock.Zero();

 		TransformEncrypt(const_cast<TUint8*>(aOutput.Ptr()) + outputStartIndex, 1);		

 		}

 	}

 void CSymmetricBlockCipherImpl::DoProcessFinalDecryptL(const TDesC8& aInput, TDes8& aOutput)

 	{

 	if (MaxFinalOutputLength(aInput.Length()) > aOutput.MaxLength() - aOutput.Length())

 		{

 		User::Leave(KErrOverflow);

 		}

 	// Input length (including inputstore) must be a multiple of the 

 	// block size in length

 	if ((aInput.Length() + iInputStore.Length()) & (iBlockBytes - 1)) 

 		{

 		User::Leave(KErrArgument);

 		}

 	TInt bytesProcessed(0);

 	if(aInput.Length() > iBlockBytes)

 		{

 		// the last block lies entirely within aInput so decrypt everything up 

 		// to this point.

 		bytesProcessed = aInput.Length() - iBlockBytes;

 		ProcessL(aInput.Left(bytesProcessed), aOutput);

 		ASSERT(iInputStore.Length()==0); // all the blocks should have been decrypted

 		}

 	else 

 		{

 		// if the input is less than one block in length then this + input

 		// store should combine to give exactly one block of data

 		ASSERT((iInputStore.Length() + aInput.Length()) == iBlockBytes);

 		}

 	// now contains the final ciphertext block

 	iInputStore.Append(aInput.Right(aInput.Length() - bytesProcessed)); 

 	// Decrypt the last _padding_ blocksize into a new buffer

 	TransformDecrypt(const_cast<TUint8*>(iInputStore.Ptr()), 1);

 	// Unpad the last block and append to output

 	iPadding->UnPadL(iInputStore, aOutput);

 	iPaddingBlock.Zero();

 	iInputStore.Zero();

 	}