/*

* Copyright (c) 1999-2009 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: 

*

*/

#include <e32base.h>

#include <random.h>

#include <padding.h>

#include <securityerr.h>

#include <cryptopanic.h>

/* CPadding */

CPadding::CPadding(void) : iBlockBytes(-1)

	{

	}

EXPORT_C CPadding::CPadding(TInt aBlockBytes) : iBlockBytes(aBlockBytes)

	{

	__ASSERT_ALWAYS(aBlockBytes > 0, User::Invariant());

	}

EXPORT_C void CPadding::SetBlockSize(TInt aBlockBytes)

	{

	__ASSERT_ALWAYS(aBlockBytes > 0, User::Invariant());

	iBlockBytes = aBlockBytes;

	}

EXPORT_C TInt CPadding::BlockSize(void) const

	{

	return iBlockBytes;

	}

EXPORT_C TInt CPadding::MaxPaddedLength(TInt /*aInputBytes*/) const

	{

	return BlockSize();

	}

EXPORT_C TInt CPadding::MaxUnPaddedLength(TInt aInputBytes) const

	{

	return aInputBytes - MinPaddingLength();

	}

EXPORT_C void CPadding::PadL(const TDesC8& aInput, TDes8& aOutput)

	{

	// Check that the input is small enough to fit inside one padded block

	__ASSERT_DEBUG(aInput.Length() <= BlockSize() - MinPaddingLength(), 	

		User::Panic(KCryptoPanic, ECryptoPanicPadInputTooLarge));

	// Check that the output descriptor supplied is large enough to store the result

	__ASSERT_DEBUG(aOutput.MaxLength() >= MaxPaddedLength(aInput.Length()), 	

		User::Panic(KCryptoPanic, ECryptoPanicOutputDescriptorOverflow));

	// Call the virtual function, implemented by derived classes

	DoPadL(aInput, aOutput);

	}

/* CPaddingNone */

EXPORT_C CPaddingNone* CPaddingNone::NewL(TInt aBlockBytes)

	{

	__ASSERT_ALWAYS(aBlockBytes > 0, User::Leave(KErrArgument));

	return new(ELeave)CPaddingNone(aBlockBytes);

	}

EXPORT_C CPaddingNone* CPaddingNone::NewLC(TInt aBlockBytes)

	{

	CPaddingNone* self = CPaddingNone::NewL(aBlockBytes);

	CleanupStack::PushL(self);

	return self;

	}

EXPORT_C CPaddingNone::CPaddingNone(TInt aBlockBytes):CPadding(aBlockBytes)

	{

	}

void CPaddingNone::DoPadL(const TDesC8& aInput,TDes8& aOutput)

	{

	aOutput.Append(aInput);

	}

void CPaddingNone::UnPadL(const TDesC8& aInput,TDes8& aOutput)

	{

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

	aOutput.Append(aInput);

	}

TInt CPaddingNone::MinPaddingLength(void) const

	{

	return 0;

	}

TInt CPaddingNone::MaxPaddedLength(TInt aInputSize) const

	{

	return aInputSize;

	}

/* CPaddingSSLv3 */

EXPORT_C CPaddingSSLv3* CPaddingSSLv3::NewL(TInt aBlockBytes)

	{

	__ASSERT_ALWAYS(aBlockBytes > 0, User::Leave(KErrArgument));

	return new(ELeave)CPaddingSSLv3(aBlockBytes);	

	}

EXPORT_C CPaddingSSLv3* CPaddingSSLv3::NewLC(TInt aBlockBytes)

	{

	CPaddingSSLv3* self = CPaddingSSLv3::NewL(aBlockBytes);

	CleanupStack::PushL(self);

	return self;

	}

EXPORT_C CPaddingSSLv3::CPaddingSSLv3(TInt aBlockBytes):CPadding(aBlockBytes)

	{

	}

void CPaddingSSLv3::DoPadL(const TDesC8& aInput,TDes8& aOutput)

	{

	TInt paddingBytes=BlockSize()-(aInput.Length()%BlockSize());

	aOutput.Append(aInput);

	aOutput.SetLength(aOutput.Length()+paddingBytes);

	for (TInt i=1;i<=paddingBytes;i++)

		{

		aOutput[aOutput.Length()-i]=(TUint8)(paddingBytes-1);

		}

	}

void CPaddingSSLv3::UnPadL(const TDesC8& aInput,TDes8& aOutput)

	{

	TInt paddingLen = aInput[aInput.Length()-1] + 1;

	if (paddingLen > aInput.Length())

		{

		User::Leave(KErrInvalidPadding);

		}

	TInt outlen = aInput.Length() - paddingLen;

	__ASSERT_DEBUG(aOutput.MaxLength() >= outlen, User::Panic(KCryptoPanic, ECryptoPanicOutputDescriptorOverflow));

	aOutput.Append(aInput.Left(outlen));

	}

TInt CPaddingSSLv3::MinPaddingLength(void) const

	{

	//if aInputBytes is 1 less than the blocksize then we get 1 byte of padding

	return 1;

	}

TInt CPaddingSSLv3::MaxPaddedLength(TInt aInputBytes) const

	{

	TUint padBytes = BlockSize() - (aInputBytes % BlockSize());

	return padBytes + aInputBytes;

	}

/* CPaddingPKCS1Signature */

EXPORT_C CPaddingPKCS1Signature* CPaddingPKCS1Signature::NewL(TInt aBlockBytes)

	{

	return new(ELeave)CPaddingPKCS1Signature(aBlockBytes);

	}

EXPORT_C CPaddingPKCS1Signature* CPaddingPKCS1Signature::NewLC(TInt aBlockBytes)

	{

	CPaddingPKCS1Signature* self = CPaddingPKCS1Signature::NewL(aBlockBytes);

	CleanupStack::PushL(self);

	return self;

	}

EXPORT_C CPaddingPKCS1Signature::CPaddingPKCS1Signature(TInt aBlockBytes)

	: CPadding(aBlockBytes)

	{

	}

void CPaddingPKCS1Signature::DoPadL(const TDesC8& aInput,TDes8& aOutput)

	{

	aOutput.SetLength(BlockSize());

	TInt i;

	TInt j;

	aOutput[0]=0;

	TInt startOfData=BlockSize()-aInput.Length();

	// PKCS1 also specifies a block type 0 for private key operations but

	// does not recommend its use. This block type (0) is compatible with 

	// unpadded data though so you can create PKCS1 type 0 blocks using 

	// CPaddingNone.

	aOutput[1]=1;				// Block type 1 (private key operation)

	for (i=2;i<(startOfData-1);i++)

		{

		aOutput[i]=0xff;

		}

	j=0;

	aOutput[startOfData-1]=0;				// separator

	for (i=startOfData;i<BlockSize();i++,j++)

		{

		aOutput[i]=aInput[j];

		}

	}

void CPaddingPKCS1Signature::UnPadL(const TDesC8& aInput,TDes8& aOutput)

	{

	// erm, oops, this is not quite as simplistic as it first looks...

	// our integer class will strip any leading zeros so we might actually

	// get some real data that starts out looking like padding but isn't 

	// really

	TInt inputLen = aInput.Length();

	if (inputLen <=0 )				

		User::Leave(KErrInvalidPadding);	//	Invalid padding data

	// Leading zero may have been stripped off by integer class

	TInt dataStart=0;

	if (aInput[dataStart] == 0)

		{

		++dataStart;

		}

	if (dataStart < inputLen && aInput[dataStart])		//	might be mode one or mode zero,

		{

		++dataStart;

		while (dataStart < inputLen && aInput[dataStart] == 0xff)

			{

			++dataStart;

			}

		if (dataStart == inputLen || aInput[dataStart])	//	this would mean theres no zero between 0x01ff and data...so its not mode one

			dataStart=0;			//	mode zero, start from begining of data

		else

			++dataStart;

		}

	else							//	We've definitely got a mode zero 

		{							//	or broken data, assume mode zero

		dataStart=0;		

		}

	TInt len=inputLen-dataStart;

	__ASSERT_DEBUG(aOutput.MaxLength() >= len, User::Panic(KCryptoPanic, ECryptoPanicOutputDescriptorOverflow));

	aOutput.SetLength(len);

	TInt i=0;

	while (dataStart<inputLen)

		{

		aOutput[i++]=aInput[dataStart++];

		}

	}

TInt CPaddingPKCS1Signature::MinPaddingLength(void) const

	{

	return 11; //0x00, 0x01, <MIN of 8 0xFF octets> , 0x00

	}

/* CPaddingPKCS1Encryption */

EXPORT_C CPaddingPKCS1Encryption* CPaddingPKCS1Encryption::NewL(

	TInt aBlockBytes)

	{

	return new(ELeave)CPaddingPKCS1Encryption(aBlockBytes);

	}

EXPORT_C CPaddingPKCS1Encryption* CPaddingPKCS1Encryption::NewLC(

	TInt aBlockBytes)

	{

	CPaddingPKCS1Encryption* self = CPaddingPKCS1Encryption::NewL(aBlockBytes);

	CleanupStack::PushL(self);

	return self;

	}

EXPORT_C CPaddingPKCS1Encryption::CPaddingPKCS1Encryption(TInt aBlockBytes)

	: CPadding(aBlockBytes)

	{

	}

void CPaddingPKCS1Encryption::DoPadL(const TDesC8& aInput,TDes8& aOutput)

	{

	aOutput.SetLength(BlockSize());

	aOutput[0]=0;

	TInt startOfData=BlockSize()-aInput.Length();

	aOutput[1]=2;				// Block type 2 (public key operation)

	TBuf8<256> rnd(256);

	GenerateRandomBytesL(rnd);

	TInt i = 2;

	TInt j = 0;

	for (; i<(startOfData-1);)

		{

		if (rnd[j])

			{

			aOutput[i++]=rnd[j];

			}

		if (++j==256)

			{

			GenerateRandomBytesL(rnd);

			j=0;

			}

		}

	j=0;

	aOutput[startOfData-1]=0;				// separator

	for (i=startOfData;i<BlockSize();i++,j++)

		{

		aOutput[i]=aInput[j];

		}

	}

void CPaddingPKCS1Encryption::UnPadL(const TDesC8& aInput,TDes8& aOutput)

	{

	TInt inputLen = aInput.Length();

	if (inputLen <= 0)				

		User::Leave(KErrInvalidPadding);	//	Invalid padding data

	// Leading zero may have been stripped off by integer class

	TInt dataStart=0;

	if (aInput[dataStart] == 0)

		{

		++dataStart;

		}

	// expecting mode 2 padding, otherwise broken

	if (dataStart == inputLen || aInput[dataStart] != 2)	

		{

		User::Leave(KErrInvalidPadding);

		}

	++dataStart;

	// skip random non zero bytes

	while (dataStart < inputLen && aInput[dataStart])

		{

		++dataStart;

		}

	// expecting zero separator

	if (dataStart == inputLen || aInput[dataStart] != 0)

		{

		User::Leave(KErrInvalidPadding);		

		}

	++dataStart;

	TInt len = inputLen - dataStart;

	__ASSERT_DEBUG(aOutput.MaxLength() >= len, User::Panic(KCryptoPanic, ECryptoPanicOutputDescriptorOverflow));

	aOutput.SetLength(len);

	TInt i=0;

	while (dataStart<inputLen)

		{

		aOutput[i++]=aInput[dataStart++];

		}

	}

TInt CPaddingPKCS1Encryption::MinPaddingLength(void) const

	{

	return 11; //0x00, 0x02, <min of 8 random octets>, 0x00

	}