/*

* Copyright (c) 2001-2009 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 <apmrec.h>

#include <apmstd.h>

#include <asn1cons.h>

#include <ecom/ecom.h>

#include <ecom/implementationproxy.h>

#include "CertRecog.h"

#include "x509cert.h"

#include "x509certext.h"

const TInt KCertificateRecognizerValue = 0x101F4A71;

const TUid KUidMimeCertRecognizer = { KCertificateRecognizerValue };

// User certs

_LIT8( KDataTypeWAPCertificateResponse, "application/vnd.wap.cert-response" );

_LIT8( KDataTypeX509_USER_Certificate, "application/x-x509-user-cert" );

// CA certs

_LIT8( KDataTypeX509_CA_Certificate, "application/x-x509-ca-cert" );

_LIT8( KDataTypeWAP_WTLS_CA_Certificate, "application/vnd.wap.wtls-ca-certificate" );

const TInt KSupportedDataTypesTotal = 3;

const TInt KX509MinBufferLength = 30;

const TInt KCertRecMaxBufferLength = 80;

const TInt KASN1SequenceTagValue = 0x30;

const TInt KASN1SequenceTwoBytesLength = 0x82;

const TInt KASN1SequenceThreeBytesLength = 0x83;

const TInt KASN1VersionWrapperTagValue = 0xA0;

const TInt KASN1VersionWrapperLengthValue = 0x03;

const TInt KASN1VersionLengthValue = 0x01;

enum { EX509VersionValue1 = 0x00, EX509VersionValue2 = 0x01, EX509VersionValue3 = 0x02 };

const TInt KWTLSCertificateVersionValue = 0x01;

// ----------------------------------------------------------------------------

// CApaCertificateRecognizer

//

CApaCertificateRecognizer::CApaCertificateRecognizer()

	: CApaDataRecognizerType( KUidMimeCertRecognizer, CApaDataRecognizerType::ENormal )

	{

	iCountDataTypes = KSupportedDataTypesTotal;

	}

TUint CApaCertificateRecognizer::PreferredBufSize()

	{

	return KCertRecMaxBufferLength;

	}

TDataType CApaCertificateRecognizer::SupportedDataTypeL( TInt aIndex ) const

	{

	__ASSERT_DEBUG( aIndex >= 0 && aIndex < KSupportedDataTypesTotal,

					User::Panic( _L("RECCERT"), 0 ) );

	switch ( aIndex )

		{

		case 0:

			return TDataType( KDataTypeX509_CA_Certificate );

		case 1:

			return TDataType( KDataTypeWAP_WTLS_CA_Certificate );

		// Used to prevent warning about return paths not all returning a value

		default:

			return TDataType( KDataTypeWAPCertificateResponse );

		}

	}

void CApaCertificateRecognizer::DoRecognizeL( const TDesC& aName, const TDesC8& aBuffer )

	{

 	RFile* filePtr = FilePassedByHandleL();

 	if (filePtr)

 		{

 		ReadFileAndRecognizeL(*filePtr);

 		return;	

 		}

 	//Connect to file server

 	RFs fs;

 	User::LeaveIfError(fs.Connect());	

 	CleanupClosePushL(fs);

 	// See if the data is passed by filename

 	RFile fileToRead;	

 	TInt ret = fileToRead.Open(fs, aName, EFileRead | EFileShareReadersOnly | EFileStream);

 	CleanupClosePushL(fileToRead);

 	if (ret == KErrNone)

 		{

 		//Try the preferred buffer size first

 		ReadFileAndRecognizeL(fileToRead);

 		}

 	else

 		// If not passed by file name, can try to recognize buffer.

 		{

 		DoRecognizeBufferL(aBuffer, EFalse, fileToRead);

 		}

 	CleanupStack::PopAndDestroy(2); //fileToRead, fs		

 	}

void CApaCertificateRecognizer::ReadFileAndRecognizeL(RFile& aFileToRead)

 	{

 	TInt size=PreferredBufSize();

 	HBufC8* memForFile = HBufC8::NewLC(size);

 	TPtr8 preferredBuffer(memForFile->Des());

 	User::LeaveIfError(aFileToRead.Read(preferredBuffer, size));

 	DoRecognizeBufferL(preferredBuffer, ETrue, aFileToRead);		

 	CleanupStack::PopAndDestroy(memForFile); //memForFile	

 	}

void CApaCertificateRecognizer::DoRecognizeBufferL(const TDesC8& aBuffer,  TBool aIsFile, RFile& aFile)

	{

	// Ensure length is sufficient for checking type

   	if ( aBuffer.Size() >= 1 )

   		{

   		// First byte of X.509 certificate is an ANS.1 SEQUENCE tag

   		if ( aBuffer[0] == KASN1SequenceTagValue )

   			{

  			RecognizeX509CertL( aBuffer, aIsFile, aFile);

   			}

   		// First byte of WTLS certificate is version == 1

   		else if ( aBuffer[0] == KWTLSCertificateVersionValue )

   			{

  			RecognizeWTLSCertOrCertResponse( aBuffer, aIsFile, aFile);

   			}

 		}						

   	}

void CApaCertificateRecognizer::RecognizeX509CertL( const TDesC8& aBuffer,  TBool aIsFile, RFile& aFile )

		{

	//Basic check if this is a X509 certificate

	TBool isCertV1orV2(EFalse);

	TInt bufferSize = aBuffer.Size();

	if ( bufferSize < KX509MinBufferLength )

		{

		return;

		}

	TInt index = 1;

	// Check first sequence length byte and skip over the length value bytes

	if ( aBuffer[index] == KASN1SequenceTwoBytesLength )

		{

		index += 3;

		}

	else if ( aBuffer[index] == KASN1SequenceThreeBytesLength )

		{

		index += 4;

		}

	else

		{

		return;

		}

	// Check next byte that is another sequence start

	if ( aBuffer[index] != KASN1SequenceTagValue )

		{

		return;

		}

	++index;

	// Check second sequence length byte and skip over the length value bytes

	if ( aBuffer[index] == KASN1SequenceTwoBytesLength )

		{

		index += 3;

		}

	else if ( aBuffer[index] == KASN1SequenceThreeBytesLength )

		{

		index += 4;

		}

	else

		{

		return;

		}

	// Check for VERSION field

	if ( aBuffer[index] == KASN1VersionWrapperTagValue )

		{

		++index;

		if ( aBuffer[index] != KASN1VersionWrapperLengthValue )

			{

			return;

			}

		++index;

		if ( aBuffer[index] != EASN1Integer )

			{

			return;

			}

		++index;

		if ( aBuffer[index] != KASN1VersionLengthValue )

			{

			return;

			}

		++index;

		// The cert is X509 v1 or v2

 		if (aBuffer[index] == EX509VersionValue1 ||

 		    aBuffer[index] == EX509VersionValue2)

		    {

		    isCertV1orV2=ETrue;

		    }

		else

	 	   // The cert is neither X509 v1 nor v2

 		    {

 		   // The cert is not v3 as well 

 		   if (aBuffer[index] != EX509VersionValue3)

 			{

 			return;	

			}

 		    }		

		++index;

		}

	else

		{

		isCertV1orV2=ETrue;	

		}

	// Check for SerialNumber field

	if ( aBuffer[index] != EASN1Integer )

		{

		return;

		}

	++index;

	TInt serialNumberSize = aBuffer[index];

	++index;

	index += serialNumberSize;

	// 1 is added for the next increments of index

	if((index + 1) >= bufferSize)

		{

		return;

		}

	// Check for SIGNATURE field

	if ( aBuffer[index] != KASN1SequenceTagValue )

		{

		return;

		}

	++index;

	TInt signatureSize = aBuffer[index];

	++index;

	index += signatureSize;

	if(index >= bufferSize)

		{

		return;

		}

 	// if the certificate is passed by the buffer, but not file name 

 	if (!aIsFile)	

 		{

 		// Check only the starting TAG byte of the NAME field

 		if ( aBuffer[index] == KASN1SequenceTagValue )

 			{

 			iDataType = TDataType( KDataTypeX509_CA_Certificate );

 			iConfidence = EProbable;

 			}			

 		}

 	else

 		// if the certificate is passed by file name

		{

		if (!isCertV1orV2) // x509 V3 certificate

 			{ 

 			//Get the file size

 			TInt size;

 			User::LeaveIfError(aFile.Size(size));

 			HBufC8* memForFile = HBufC8::NewLC(size);

 			TPtr8 fileContent(memForFile->Des());

 			TInt pos=0;

 			aFile.Seek(ESeekStart, pos);

 			User::LeaveIfError(aFile.Read(fileContent, size));

 			RecognizeWholeX509CertificateL(fileContent);

 			CleanupStack::PopAndDestroy(memForFile);//memForFile

			}									

 		else  // x509 V1 or V2 certificate

 			{ 

 			iDataType = TDataType( KDataTypeX509_CA_Certificate );

 			iConfidence = EProbable;				

 			}

		}

	}

void CApaCertificateRecognizer::RecognizeWholeX509CertificateL(const TDesC8& aBuffer)

 	{

 	CX509Certificate* cert = CX509Certificate::NewLC(aBuffer);

 	if (cert)

 		{

 		const CX509CertExtension* certExt = cert->Extension(KBasicConstraints);

 		if (certExt)

 			{

 			CX509BasicConstraintsExt* basic = CX509BasicConstraintsExt::NewLC(certExt->Data());

 			if (basic->IsCA())

 				{

 				iDataType = TDataType( KDataTypeX509_CA_Certificate );

 				iConfidence = EProbable;					

 				}

 			else

 				{

 				iDataType = TDataType( KDataTypeX509_USER_Certificate );

 				iConfidence = EProbable;										

 				}

 			CleanupStack::PopAndDestroy(basic); //basic				

			}

 		else

 			{

 			iDataType = TDataType( KDataTypeX509_USER_Certificate );

 			iConfidence = EProbable;														

 			}

 		}

 	CleanupStack::PopAndDestroy(cert); //cert

 	}

void CApaCertificateRecognizer::RecognizeWTLSCertOrCertResponse( const TDesC8& aBuffer, TBool /*aIsFile*/, RFile& /*aFile*/ )

	{

	if ( aBuffer.Size() >= 3 )

		{

		// Check next byte is signature algorithm value from 0 - 2

		if ( aBuffer[1] == 0x00 || aBuffer[1] == 0x01 || aBuffer[1] == 0x02 )

			{

			// Check Identifier Type for Issuer Identifier

			if ( aBuffer[2] == 0x01 )

				{

				iDataType = TDataType( KDataTypeWAP_WTLS_CA_Certificate );

				}

			else

				{

				iDataType = TDataType( KDataTypeWAPCertificateResponse );

				}

			iConfidence = EPossible;

			}

		}

	}

CApaDataRecognizerType* CApaCertificateRecognizer::CreateRecognizerL()

	{

	return new (ELeave) CApaCertificateRecognizer();

	}

const TImplementationProxy ImplementationTable[] = 

	{

		IMPLEMENTATION_PROXY_ENTRY(0x102034A2, CApaCertificateRecognizer::CreateRecognizerL)

	};

EXPORT_C const TImplementationProxy* ImplementationGroupProxy(TInt& aTableCount)

	{

	aTableCount = sizeof(ImplementationTable) / sizeof(TImplementationProxy);

	return ImplementationTable;

	}