/*

* Copyright (c) 2004-2009 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 <asn1dec.h>

#include <x509keys.h>

#include <x509cert.h>

#include "asnpkcs.h"

#include <pbe.h>

#include <pbedata.h>

#include <keyidentifierutil.h>

/*static*/ EXPORT_C CDecPKCS8Data* TASN1DecPKCS8::DecodeDERL(const TDesC8& aBinaryData)

{

	return (CDecPKCS8Data::NewL(aBinaryData));

}

/*

EncryptedPrivateKeyInfo ::= SEQUENCE {

  encryptionAlgorithm EncryptionAlgorithmIdentifier,

  encryptedData EncryptedData }

EncryptionAlgorithmIdentifier ::= AlgorithmIdentifier

EncryptedData ::= OCTET STRING

*/

/*static*/ EXPORT_C CDecPKCS8Data* TASN1DecPKCS8::DecodeEncryptedDERL(const TDesC8& aBinaryData, const TDesC8& aPassword)

{

	TASN1DecGeneric seqGen(aBinaryData);

	seqGen.InitL();

	if (seqGen.Tag() != EASN1Sequence)

		{

		User::Leave(KErrArgument);

		}

	TASN1DecSequence dec;

	CArrayPtrFlat<TASN1DecGeneric>* theData = dec.DecodeDERLC(seqGen);

	TInt seqIndex = 0;

	TInt count = theData->Count();

	if (seqIndex >= count)

		{

		User::Leave(KErrArgument);		

		}

//	Get the first part of the sequence -> PKCS5 data

	TASN1DecGeneric* pkcs5 = theData->operator[](seqIndex);

	TPtrC8 theContent(pkcs5->Encoding());	//	expect this to be a sequence

	CPBEncryptParms* encryptParams = TASN1DecPKCS5::DecodeDERL(theContent);

	CleanupStack::PushL(encryptParams);

//	Create the decryptor	

	CPBEncryptElement* encryptElement = CPBEncryptElement::NewLC(aPassword, *encryptParams);

	CPBDecryptor* decryptor = encryptElement->NewDecryptLC();

//	Decrypt the final part of the sequence -> encrypted PKCS8 object

	TASN1DecGeneric* pkcs8 = theData->operator[](count-1);

	if (pkcs8->Tag() != EASN1OctetString)

		{

		User::Leave(KErrArgument);

		}

	TPtrC8 encryptedKey(pkcs8->GetContentDER());

	TUint encryptLength = encryptedKey.Length();

	TUint maxDecryptLength = decryptor->MaxOutputLength(encryptLength);

	if (maxDecryptLength<=0)

		{

		User::Leave(KErrGeneral);		

		}

	HBufC8* decryptOutput = HBufC8::NewLC(encryptLength);

	TPtr8 decryptOutputPtr(decryptOutput->Des());

	decryptOutputPtr.FillZ();

	decryptor->Process(encryptedKey, decryptOutputPtr);

	CDecPKCS8Data* pkcs8Data = CDecPKCS8Data::NewL(decryptOutputPtr);

	//	decryptOutput decryptor encryptElement 

	//	encryptParams theData

	CleanupStack::PopAndDestroy(5, theData);

	return (pkcs8Data);

}

/*

Sample cleartext pkcs8 data from pkcs8dsa.001:

          SEQUENCE

30          Tag: Constructed sequence

81 c8       Length (may be one or more bytes)

            INTEGER

02            Tag: Integer

01            Length: 1 byte

00            Value: 0

            SEQUENCE    

30            Tag: Constructed sequence

81 a9         Length (may be one or more bytes)

              OID

06              Tag: OID

07              Length: 7 bytes

2a 86 48 ce 38 04 01

                Value: dsa (1 2 840 10040 4 1)

*/

_LIT8(KPKCS8DataVersion0, "\x02\x01\x00");

_LIT8(KPKCS8DataOIDDSA, "\x06\x07\x2a\x86\x48\xce\x38\x04\x01");

_LIT8(KPKCS8DataOIDRSA, "\x06\x09\x2a\x86\x48\x86\xf7\x0d\x01\x01\x01");

/*static*/ EXPORT_C TBool TASN1DecPKCS8::IsPKCS8Data(const TDesC8& aBinaryData)

	{

	// We don't decode the data because we may only have the first few bytes -

	// instead we check the ASN1 by hand.

	ASSERT(aBinaryData.Length() >= KIsPKCS8DataMinLength);

	TInt pos = 0;

	return

		IsASN1Sequence(aBinaryData, pos) &&

		IsExpectedData(aBinaryData, pos, KPKCS8DataVersion0) &&

		IsASN1Sequence(aBinaryData, pos) &&

		(IsExpectedData(aBinaryData, pos, KPKCS8DataOIDDSA) ||

		 IsExpectedData(aBinaryData, pos, KPKCS8DataOIDRSA));

	}

/*

Sample encrypted pkcs8 data from encryptPK8rsa1.txt

          SEQUENCE

30          Tag: Constructed sequence

82 01 a3    Length (may be one or more bytes)

            SEQUENCE

30            Tag: Constructed sequence

3d            Length (may be one or more bytes)

              OID

06              Tag: OID

09              Length: 9 bytes

2a 86 48 86 f7 0d 01 05 0d

                Value: pkcs5PBES2 (1 2 840 113549 1 5 13)

              SEQUENCE

30              Tag: Constructed sequence

30              Length (may be one or more bytes)

                SEQUENCE

30                Tag: Constructed sequence

1b                Length (may be one or more bytes)

                  OID

06                  Tag: OID

09                  Length: 9 bytes

2a 86 48 86 f7 0d 01 05 0c

                    Value: pkcs5PBKDF2 (1 2 840 113549 1 5 12)

*/

_LIT8(KEncryptedPKCS8DataOIDpkcs5PBES2, "\x06\x09\x2a\x86\x48\x86\xf7\x0d\x01\x05\x0d");

_LIT8(KEncryptedPKCS8DataOIDpkcs5PBKDF2, "\x06\x09\x2a\x86\x48\x86\xf7\x0d\x01\x05\x0c");

EXPORT_C TBool TASN1DecPKCS8::IsEncryptedPKCS8Data(const TDesC8& aBinaryData)

	{

	// We don't decode the data because we may only have the first few bytes -

	// instead we check the ASN1 by hand.

	ASSERT(aBinaryData.Length() >= KIsEncryptedPKCS8DataMinLength);

	TInt pos = 0;

	return

		IsASN1Sequence(aBinaryData, pos) &&

		IsASN1Sequence(aBinaryData, pos) &&

		IsExpectedData(aBinaryData, pos, KEncryptedPKCS8DataOIDpkcs5PBES2) &&

		IsASN1Sequence(aBinaryData, pos) &&

		IsASN1Sequence(aBinaryData, pos) &&

		IsExpectedData(aBinaryData, pos, KEncryptedPKCS8DataOIDpkcs5PBKDF2);

	}

/**

 * Determine if the some data represents the start of an ASN1 sequence.  The

 * data is specified by a descriptor and an offset.  If the data matches, the

 * offset is advanced to point to the contents of the sequence.

 */

TBool TASN1DecPKCS8::IsASN1Sequence(const TDesC8& aBinaryData, TInt& aPos)

	{

	// Check we have enough data

	if ((aPos + 2) >= aBinaryData.Length())

		{

		return EFalse;

		}

	// Check the outermost sequence is valid

	if (aBinaryData[aPos++] != 0x30 /* constructed sequence */)

		{

		return EFalse;

		}

	// Skip sequence length

	TInt length0 = aBinaryData[aPos++];

	if (length0 & 0x80)

		{

		aPos += length0 & 0x7f;

		}

	return ETrue;

	}

/**

 * Determine if some data starts with an expected string.  The data is specified

 * by a descriptor and an offset.  If the data matches, the offset is advanced

 * to point after the match.

 */

TBool TASN1DecPKCS8::IsExpectedData(const TDesC8& aBinaryData, TInt& aPos, const TDesC8& aExpectedData)

	{

	TInt length = aExpectedData.Length();

	// Check we have enough data

	if (aPos + length >= aBinaryData.Length())

		{

		return EFalse;

		}

	// Check data matches	

	if (aBinaryData.Mid(aPos, length) != aExpectedData)

		{

		return EFalse;

		}

	aPos += length;

	return ETrue;

	}

//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	

//	PKCS#8 object data representation

//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	

/*static*/ CDecPKCS8Data* CDecPKCS8Data::NewL(const TDesC8& aData)

{

	CDecPKCS8Data* me = new (ELeave) CDecPKCS8Data();

	CleanupStack::PushL(me);

	me->ConstructL(aData);

	CleanupStack::Pop(me);

	return (me);

}

CDecPKCS8Data::CDecPKCS8Data()

{}

CDecPKCS8Data::~CDecPKCS8Data()

{

	if (iKeyPairData)

	{

		iKeyPairData->Release();

		iKeyPairData = NULL;

	}

	if (iAttributes)

	{

		delete iAttributes;

		iAttributes = NULL;

	}

}

//	Because this is part of construction, don't rely on

//	cleanup of partially constructed items...

void CDecPKCS8Data::ConstructL(const TDesC8& aData)

	{

	TASN1DecGeneric seqGen(aData);

	seqGen.InitL();

	if (seqGen.Tag() != EASN1Sequence)

		{

		User::Leave(KErrArgument);

		}

	TASN1DecSequence seq;

	CArrayPtrFlat<TASN1DecGeneric>* seqContents = seq.DecodeDERLC(seqGen);

	if (seqContents->Count() < 3 || seqContents->Count() > 4)

		{

		User::Leave(KErrArgument);

		}

//	VERSION

	if (seqContents->At(0)->Tag() != EASN1Integer)

		{

		User::Leave(KErrArgument);

		}

	TASN1DecInteger intDecoder;

	iVersion = intDecoder.DecodeDERShortL(*(seqContents->At(0)));

	if (iVersion!=0)

		{

		User::Leave(KErrArgument);

		}

//	ALGORITHM

	CX509AlgorithmIdentifier* algorithm = CX509AlgorithmIdentifier::NewLC(seqContents->At(1)->Encoding());

	iAlgorithmID = algorithm->Algorithm();

//	KEY DATA

	switch (iAlgorithmID)

		{//	Only support RSA, DSA, DH

		case ERSA:

			iKeyPairData = CPKCS8KeyPairRSA::NewL(*(seqContents->At(2)));

			break;

		case EDSA:

			{

			TPtrC8 params(algorithm->EncodedParams());		

			iKeyPairData = CPKCS8KeyPairDSA::NewL(params, *(seqContents->At(2)));

			break;

			}

		case EDH: // Currently not supported because no test data is available

		default:

			User::Leave(KErrNotSupported);

			break;

		}

	CleanupStack::PopAndDestroy(algorithm);

	if (seqContents->Count() == 4)

		{

		// I think we should check the tag is zero here, but we're going to be

		// lenient due to lack of real test data

		//if (seqContents->At(3)->Tag() != 0) // Implicitly tagged

		//	{

		//	User::Leave(KErrArgument);

		//	}

		iAttributes = seqContents->At(3)->Encoding().AllocL();

		}

	CleanupStack::PopAndDestroy(seqContents);

	}

//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	

//	RSA decoding

//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	

/*static*/ MPKCS8DecodedKeyPairData* CPKCS8KeyPairRSA::NewL(const TASN1DecGeneric& aSource)

{

	CPKCS8KeyPairRSA* me = new (ELeave) CPKCS8KeyPairRSA();

	CleanupStack::PushL(me);

	me->ConstructL(aSource);

	CleanupStack::Pop(me);

	return (me);

}

MPKCS8DecodedKeyPairData::~MPKCS8DecodedKeyPairData()

	{	

	}

CPKCS8KeyPairRSA::~CPKCS8KeyPairRSA()

{

	delete iPublicKey;

	delete iPrivateKey;

}

void CPKCS8KeyPairRSA::Release()

{

	delete this;

}

void CPKCS8KeyPairRSA::GetKeyIdentifierL(TKeyIdentifier& aKeyIdentifier) const

{

	if (iPublicKey)

		KeyIdentifierUtil::RSAKeyIdentifierL(*iPublicKey, aKeyIdentifier);	

	else

		User::Leave(KErrNotReady);

}

TUint CPKCS8KeyPairRSA::KeySize() const

{

	if (!iPublicKey)

	{

		ASSERT(EFalse);

		return (0xffffffff);

	}

	const TInteger& modulus = iPublicKey->N();

	TUint size = modulus.BitCount();

	return (size);

}

void CPKCS8KeyPairRSA::ConstructL(const TASN1DecGeneric& aSource)

{

	TPtrC8 theContent(aSource.GetContentDER());

	TASN1DecRSAKeyPair keyPairDecoder;

	TInt tempPos = 0;

	keyPairDecoder.DecodeDERL(theContent, tempPos, iPublicKey, iPrivateKey);

}

//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	

//	DSA decoding

//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	//	\\	

/*static*/ MPKCS8DecodedKeyPairData* CPKCS8KeyPairDSA::NewL(const TDesC8& aParamsData, const TASN1DecGeneric& aSource)

{

	CPKCS8KeyPairDSA* me = new (ELeave) CPKCS8KeyPairDSA();

	CleanupStack::PushL(me);

	me->ConstructL(aParamsData, aSource);

	CleanupStack::Pop(me);

	return (me);

}

CPKCS8KeyPairDSA::~CPKCS8KeyPairDSA()

{

	delete iPublicKey;

	delete iPrivateKey;

}

void CPKCS8KeyPairDSA::Release()

{

	delete this;

}

void CPKCS8KeyPairDSA::GetKeyIdentifierL(TKeyIdentifier& aKeyIdentifier) const

{

	if (iPublicKey)

		KeyIdentifierUtil::DSAKeyIdentifierL(*iPublicKey, aKeyIdentifier);	

	else

		User::Leave(KErrNotReady);

}

TUint CPKCS8KeyPairDSA::KeySize() const

{

	if (!iPublicKey)

	{

		ASSERT(EFalse);

		return (0xffffffff);

	}

	const TInteger& P = iPublicKey->P();

	TUint size = P.BitCount();

	return (size);

}

void CPKCS8KeyPairDSA::ConstructL(const TDesC8& aParamsData, const TASN1DecGeneric& aSource)

{

	TX509KeyFactory keyFactory;

	CDSAParameters* params = keyFactory.DSAParametersL(aParamsData);

	CleanupStack::PushL(params);

	RInteger P = RInteger::NewL(params->P());

	CleanupStack::PushL(P);

	RInteger Q = RInteger::NewL(params->Q());

	CleanupStack::PushL(Q);

	RInteger G = RInteger::NewL(params->G());

	CleanupStack::PushL(G);

	if (aSource.Tag() != EASN1OctetString)

		{

		User::Leave(KErrArgument);

		}

	TASN1DecOctetString  octetDecoder;

	HBufC8* wrapped = octetDecoder.DecodeDERL(aSource);

	CleanupStack::PushL(wrapped);	

	TASN1DecGeneric integer(*wrapped);

	integer.InitL();

	if (integer.Tag() != EASN1Integer)

		{

		User::Leave(KErrArgument);

		}		

	TASN1DecInteger decInt;

	RInteger X = decInt.DecodeDERLongL(integer);

	CleanupStack::PopAndDestroy(wrapped);

	CleanupStack::PushL(X);

	RInteger P1 = RInteger::NewL(params->P());

	CleanupStack::PushL(P1);

	RInteger Q1 = RInteger::NewL(params->Q());

	CleanupStack::PushL(Q1);

	RInteger G1 = RInteger::NewL(params->G());

	CleanupStack::PushL(G1);

	RInteger Y = TInteger::ModularExponentiateL(G, X, P);

	CleanupStack::PushL(Y);

	iPublicKey = CDSAPublicKey::NewL(P1, Q1, G1, Y);