/*

 * Copyright (c) 2006-2009 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 "pkcs12recog.h"

 #include <apmrec.h>

 #include <apmstd.h>

 #include <ecom/ecom.h>

 #include <ecom/implementationproxy.h>

 #include <f32file.h>

 /** UID for PKCS#12 mime-type recognizer */

 static const TUint KPkcs12RecognizerImplementationId = 0x20001520;

 static const TUid KUidMimePkcs12Recognizer = { KPkcs12RecognizerImplementationId };

 /** 

 Minimum buffer size assuming worst-case 3 byte lengths for variable

 length fields. The file will never be smaller that this because it must

 also contain either the MacData or be a signed object.

 SEQ 5 bytes

 INTEGER 3 bytes

 SEQ 5 bytes

 OID 11 bytes

 total = 24

 */

 static const TInt KPkcs12MinBufSize = 24;

 /** Mime-type for PKCS#12 */

 _LIT8(KDataTypePkcs12, "application/x-pkcs12");

 /** The number of mime-types recognised */

 static const TInt KSupportedDataTypesTotal = 1;

 // ASN.1 / DER constants

 /** DER encoding of an ASN.1 sequence tag */

 static const TUint8 KDerSequenceOctet = 0x30;

 /** DER encoding of an ASN.1 integer tag */

 static const TUint8 KDerIntegerOctet = 0x02;

 /** Expected PKCS#12 version number */

 static const TInt KPkcs12Version = 3;

 /**

 DER encoding of PKCS#7 data content type OID

 OID = 1.2.840.113549.1.7.1

 */		

 static const TUint8 KPkcs7DataOid[] = 

 	{

 	0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x07, 0x01

 	};	

 /** Length of encoded PKCS#7 data OID */	

 static const TUint KPkcs7DataOidLen = sizeof(KPkcs7DataOid);		

 /**

 DER encoding of PKCS#7 signed data content type OID

 OID = 1.2.840.113549.1.7.2

 */	

 static const TUint8 KPkcs7SignedDataOid[] = 

 	{

 	0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x07, 0x02

 	};	

 /** Length of encoded PKCS#7 signed data OID */	

 static const TUint KPkcs7SignedDataOidLen = sizeof(KPkcs7SignedDataOid);	

 /** PKCS#12 recognizer panic identifier */

 _LIT(KPkcs12RecogPanic, "PKCS12RECOG");	

 CPkcs12Recognizer::CPkcs12Recognizer()

 	: CApaDataRecognizerType(KUidMimePkcs12Recognizer, CApaDataRecognizerType::ENormal)

 	{

 	iCountDataTypes = KSupportedDataTypesTotal;

 	}

 TUint CPkcs12Recognizer::PreferredBufSize()

 	{

 	return KPkcs12MinBufSize;

 	}

 TDataType CPkcs12Recognizer::SupportedDataTypeL(TInt aIndex) const

 	{

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

 					Panic(EPanicInvalidDataType));

 	if (aIndex < 0 || aIndex >= KSupportedDataTypesTotal)

 		{

 		User::Leave(KErrArgument);

 		}

 	return TDataType(KDataTypePkcs12);

 	}

 void CPkcs12Recognizer::DoRecognizeL(const TDesC& aName, const TDesC8& aBuffer)

 	{

 	__UHEAP_MARK;

 	iConfidence = ENotRecognized;

 	TPtrC8 pkcs12Buffer(aBuffer);

 	TBuf8<KPkcs12MinBufSize> fileBuffer;

 	if (aBuffer.Length() < KPkcs12MinBufSize)

 		{										

 		if (RFile* fh = FilePassedByHandleL()) 

 			{

 			User::LeaveIfError(fh->Read(0, fileBuffer, KPkcs12MinBufSize));

 			}

 		else 

 			{

 			// no file handle so attempt to read the file. This may

 			// fail if the file is in a private directory

 			RFs fs;

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

 			CleanupClosePushL(fs);

 			RFile file;			

 			TInt err = file.Open(fs, aName, EFileRead | EFileShareAny | EFileStream);

 			// do nothing if the file fails to open, for any reason

 			if (err == KErrNone)

 				{

 				CleanupClosePushL(file);

 				User::LeaveIfError(file.Read(0, fileBuffer, KPkcs12MinBufSize));

 				CleanupStack::PopAndDestroy(&file);

 				}

 			CleanupStack::PopAndDestroy(&fs);

 			}		

 		// buffer does not exist or is too small so attempt to 

 		// read a buffer from the file		

 		pkcs12Buffer.Set(fileBuffer);			

 		}

 	if (pkcs12Buffer.Length() > 0 && DoRecognizeBufferL(pkcs12Buffer))

 		{

 		iDataType = TDataType(KDataTypePkcs12);

 		iConfidence = EProbable;

 		if (HasPkcs12Extension(aName)) 

 			{

 			iConfidence = ECertain;

 			}

 		}

 	__UHEAP_MARKEND;

  	}

 TBool CPkcs12Recognizer::HasPkcs12Extension(const TDesC& aName)

 	{

 	_LIT(KPfxExt, ".pfx");

 	_LIT(KP12Ext, ".p12");

 	TBool match = EFalse;

 	// It is not possible to use a TParse/TParsePtr here because the filename

 	// supplied when a file-handle is passed is of the form ::filename.ext and

 	// is not recognised as a valid filename

 	if (aName.Length() > 4)

 		{		

 		const TPtrC ext = aName.Right(4);

 		if (ext.CompareF(KPfxExt) == 0 || ext.CompareF(KP12Ext) == 0)

 			{

 			match = ETrue;

 			}

 		}

 	return match;

 	}

 TBool CPkcs12Recognizer::DoRecognizeBufferL(const TDesC8& aBuffer)

  	{

  	TBool isPkcs12 = EFalse;

  	TUint offset = 0;

  	if (aBuffer.Length() >= KPkcs12MinBufSize)

  		{

 		// PFX

 	 	if (ConsumeSequenceL(aBuffer, offset))

  			{

  			// Version

  			TInt version; 

 			if (ConsumeIntegerL(aBuffer, offset, version)) 

 				{

 				if (version == KPkcs12Version)

 					{

 					// authSafe

 					if (ConsumeSequenceL(aBuffer, offset))

 						{

 						const TPtrC8 dataOid(KPkcs7DataOid, KPkcs7DataOidLen);

 						const TPtrC8 signedDataOid(KPkcs7SignedDataOid, KPkcs7SignedDataOidLen);

 						// check whether content-type is data or signed data					

 						if ((aBuffer.Mid(offset, KPkcs7DataOidLen).Compare(dataOid) == 0) ||

 							(aBuffer.Mid(offset, KPkcs7SignedDataOidLen).Compare(signedDataOid) == 0))

 							{

 							isPkcs12 = ETrue;

 							}

 						}

 					}

 				}

  			} 		

  		}

  	return isPkcs12;

  	}

 TBool CPkcs12Recognizer::ConsumeSequenceL(const TDesC8& aBuffer, TUint& aOffset) const

 	{

 	TBool isSequence = EFalse;

 	if (aBuffer[aOffset] == KDerSequenceOctet)

 		{

 		// sequence tag found, skip tag and length

 		aOffset++;

 		TInt length;

 		isSequence = ConsumeLengthL(aBuffer, aOffset, length);

 		}

 	return isSequence;

 	}

 TBool CPkcs12Recognizer::ConsumeLengthL(const TDesC8& aBuffer, TUint& aOffset, TInt& aLengthOctets) const

 	{	

 	TBool isValidLength = EFalse;	

 	TUint8 lengthOctet = aBuffer[aOffset];

 	if (lengthOctet & 0x80)

 		{

 		// The top bit is set so assume the length encoding is in long form

 		TUint numOctets = lengthOctet & 0x7f;

 		aOffset++;

 		if (ConsumeBase256L(aBuffer, aOffset, numOctets, aLengthOctets))

 			{			

 			if (aLengthOctets >= 0)

 				{

 				// lengths must not be -ve

 				isValidLength = ETrue;

 				}

 			}

 		}

 	else 

 		{

 		// Top bit zero so assume short form encoding i.e. one octet

 		aLengthOctets = lengthOctet & 0x7f;

 		aOffset++;

 		isValidLength = ETrue;

 		}

 	return isValidLength;

 	}

 TBool CPkcs12Recognizer::ConsumeIntegerL(const TDesC8& aBuffer, TUint& aOffset, TInt& aIntVal) const

 	{

 	TBool isValidInteger = EFalse;

 	if (aBuffer[aOffset] == KDerIntegerOctet) 

 		{

 		aOffset++;

 		TInt length;

 		if (ConsumeLengthL(aBuffer, aOffset, length))

 			{			

 			isValidInteger = ConsumeBase256L(aBuffer, aOffset, length, aIntVal);

 			}

 		}

 	return isValidInteger;

 	}

 TBool CPkcs12Recognizer::ConsumeBase256L(const TDesC8& aBuffer, TUint& aOffset, TInt aLengthOctets, TInt& aIntVal) const

 	{	

 	TInt isValid = EFalse;

 	if (aLengthOctets <= 4) 

 		{

 		aIntVal = 0;

 		while (aLengthOctets-- > 0)

 			{

 			aIntVal <<= 8;

 			aIntVal |= aBuffer[aOffset++];

 			}

 		isValid = ETrue;

 		}

 	return isValid;	

 	}	

 CApaDataRecognizerType* CPkcs12Recognizer::CreateRecognizerL()

 	{

 	return new (ELeave) CPkcs12Recognizer();

 	}

 static const TImplementationProxy ImplementationTable[] = 

 	{

 		IMPLEMENTATION_PROXY_ENTRY(KPkcs12RecognizerImplementationId, CPkcs12Recognizer::CreateRecognizerL)

 	};

 EXPORT_C const TImplementationProxy* ImplementationGroupProxy(TInt& aTableCount)

 	{

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

 	return ImplementationTable;

 	}	

 void CPkcs12Recognizer::Panic(TPkcs12RecogPanic aReason) const

 	{

 	User::Panic(KPkcs12RecogPanic, aReason);

 	}