// Copyright (c) 2002-2009 Nokia Corporation and/or its subsidiary(-ies).

// All rights reserved.

// This component and the accompanying materials are made available

// under the terms of "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 "smtpauthhelpers.h"

#include "SMTSUTIL.H"			// forward declarations for utility fns

#include <e32des8.h>

_LIT8(KPlainMechanism, "PLAIN "); //Space intentional, may find a better way of doing this.

_LIT8(KSmtpAuthLoginCommand, "AUTH LOGIN\r\n");

_LIT8(KCramMD5Mechanism, "CRAM-MD5");

_LIT8(KSmtpAuthBase64StringUsername,"username*"); // To match a folded 'username:' or 'username'

_LIT8(KSmtpAuthBase64StringPassword,"password*"); // To match a folded 'password:' or 'password'

const TInt KMaxLengthOfPlainMessageComponent = 255;

const TInt KMd5BlockLength = 64;

#define BASE64LEN(x) ((x*4)/3) // Every 3 bytes will be turned into 4 bytes

const TInt KPreambleLength = 18; //"AUTH LOGIN\r\nPLAIN "

const TInt KMaxLengthOfPlainMessage=	KPreambleLength + 1/*NUL*/ + KMaxLengthOfPlainMessageComponent/*Username*/ + 1/*NUL*/ + KMaxLengthOfPlainMessageComponent/*Password*/ + 2/* /r/n */;

const TInt KMaxLengthOfPlainMessageBase64= BASE64LEN(KMaxLengthOfPlainMessage);

//

//CSmtpAuthMechanismHelper

//

CSmtpAuthMechanismHelper::CSmtpAuthMechanismHelper(const CSmtpSettings& aSettings) : iSettings(aSettings)

	{

	}

//

//CSmtpAuthPlainMechanismHelper

//

CSmtpAuthPlainMechanismHelper::CSmtpAuthPlainMechanismHelper(const CSmtpSettings& aSettings) : CSmtpAuthMechanismHelper(aSettings)

	{

	}

void CSmtpAuthPlainMechanismHelper::GetNextClientMessageL(TDes8& aNextMessage)

	{

	// Build up the un-encoded authorisation string in parts

 	HBufC8* authString = HBufC8::NewMaxLC(KMaxLengthOfPlainMessage); 

 	TPtr8 authStringPtr = authString->Des();

	TBuf8<1> nul;

	nul.SetLength(1);

	nul[0] = 0;

	authStringPtr = nul; // Start with the NUL

	TPtrC8 loginName = iSettings.LoginName();

	TInt length= Min(loginName.Length(),KMaxLengthOfPlainMessageComponent);

	authStringPtr.Append(loginName.Left(length));

	authStringPtr.Append(nul); // Separator between login and password

	length= Min(iSettings.Password().Length(), KMaxLengthOfPlainMessageComponent);

	authStringPtr.Append(iSettings.Password().Left(length));

	// Auth string is now built, encode it

	HBufC8* encodedBuf = HBufC8::NewMaxLC(KMaxLengthOfPlainMessageBase64); 

	TPtr8 encodedBufPtr = encodedBuf->Des();

	iEncoder.Encode(authStringPtr,encodedBufPtr);

	// Now build the message

	iNextClientMessage.Zero();

 	iNextClientMessage.Append(KSmtpAuthCommand);

 	iNextClientMessage.Append(KPlainMechanism);

	iNextClientMessage.Append(encodedBufPtr);

 	iNextClientMessage.Append(KSmtpCrLf);

 	aNextMessage = iNextClientMessage;

	CleanupStack::PopAndDestroy(encodedBuf);

	CleanupStack::PopAndDestroy(authString);		

	}

void CSmtpAuthPlainMechanismHelper::SetLastServerMessageL(const TDesC8& /*aLastMessage*/, TBool /*aIsMultiLineResponse*/)

	{

	//iLastServerMessage.Set(aLastMessage);

	}

//

//CSmtpAuthLoginMechanismHelper

//

CSmtpAuthLoginMechanismHelper* CSmtpAuthLoginMechanismHelper::NewL(const CSmtpSettings& aSettings)  

	{

	CSmtpAuthLoginMechanismHelper* self= new (ELeave) CSmtpAuthLoginMechanismHelper(aSettings);

	CleanupStack::PushL(self);

	self->ConstructL();

	CleanupStack::Pop();	                                

	return self;

	}

CSmtpAuthLoginMechanismHelper::CSmtpAuthLoginMechanismHelper(const CSmtpSettings& aSettings) : CSmtpAuthMechanismHelper(aSettings)

	{

	}

CSmtpAuthLoginMechanismHelper::~CSmtpAuthLoginMechanismHelper()

	{

	delete iBase64LoginName;

	delete iBase64Password;

	}

void CSmtpAuthLoginMechanismHelper::ConstructL()

	{

	TInt len=(((iSettings.LoginName().Length()/3)+1)*4)+2; // length of LoginName in base 64 + 2 for CRLF

	iBase64LoginName=HBufC8::NewL(len);

	TPtr8 authString(iBase64LoginName->Des());

	iEncoder.Encode(iSettings.LoginName(),authString);

	authString.Append(KSmtpCrLf);

	len=(((iSettings.Password().Length()/3)+1)*4)+2; // length of Password in base 64 + 2 for CRLF

	iBase64Password=HBufC8::NewL(len);

	authString.Set(iBase64Password->Des());

	iEncoder.Encode(iSettings.Password(),authString);

	authString.Append(KSmtpCrLf);

	}

void CSmtpAuthLoginMechanismHelper::GetNextClientMessageL(TDes8& aNextMessage)

	{

	iNextClientMessage.Zero();

	switch (iState)

		{

		case ESendingAuth:

			iNextClientMessage=KSmtpAuthLoginCommand;

			break;

		case ESendingLoginName:

			iNextClientMessage=*iBase64LoginName;

			break;

		case ESendingPassword:

			iNextClientMessage=*iBase64Password;

			break;

		default:

	        gPanic(EImsmSmtpAuthLoginBadState);

			break;

		}

	aNextMessage=iNextClientMessage;

	}

void CSmtpAuthLoginMechanismHelper::SetLastServerMessageL(const TDesC8& aLastMessage, TBool /*aIsMultiLineResponse*/)

	{

	HBufC8* decodedMessage = NULL;

	TInt lastMessageLength = aLastMessage.Length();

    // Decode the SMTP response from the Base64 original

    if (lastMessageLength > 0)

        {

        decodedMessage = HBufC8::NewLC(lastMessageLength); // already on stack

        // Get pointer to response minus the "334 " at the start

        TPtrC8 response = aLastMessage.Right(lastMessageLength - 4);

        TPtr8  destination = decodedMessage->Des();

        iEncoder.Decode(response, destination);

        }

	switch (iState)

		{

		case ESendingAuth:

            if (decodedMessage)

                {

                // Match against 'username*'

                if (decodedMessage->Des().MatchF(KSmtpAuthBase64StringUsername) == KErrNotFound)

					{

                    User::Leave(KErrNotSupported);

					}

				//Some SMTP server don't follow the RFC 2554 completely, so at the end of 334 replies it appends information

				//string which is not BASE64 encoded. In such cases, after decoding the first 334 reply, it sometimes 

				//leaves BASE64 decoder in incorrect state. So the second reply isn't decoded properly, to avoid 

				//this we need to initialise the encoder

				iEncoder.Initialise();

                iState = ESendingLoginName;

                }

            else

                {

				User::Leave(KErrNotSupported);

				}

			break;

		case ESendingLoginName:

			if (decodedMessage)

                {

                // Match against 'password*'

                if (decodedMessage->Des().MatchF(KSmtpAuthBase64StringPassword) == KErrNotFound)

					{

                    User::Leave(KErrNotSupported);

					}

				//Some SMTP server don't follow the RFC 2554 completely, so at the end of 334 replies it appends information

				//string which is not BASE64 encoded. In such cases, after decoding the first 334 reply, it sometimes 

				//leaves BASE64 decoder in incorrect state. So the second reply isn't decoded properly, to avoid 

				//this we need to initialise the encoder

				iEncoder.Initialise();

                iState = ESendingPassword;

                }

			else

                {

				User::Leave(KErrNotSupported);

				}

			break;

		case ESendingPassword: // the helper shouldn't be handling the 235 response

		default:

			User::Leave(KErrNotSupported);

			break;

		}

	if (decodedMessage)

		{

		CleanupStack::PopAndDestroy(decodedMessage);

		}

	}

//

//CSmtpAuthCramMd5MechanismHelper

//

CSmtpAuthCramMd5MechanismHelper* CSmtpAuthCramMd5MechanismHelper::NewL(const CSmtpSettings& aSettings)  

	{

	CSmtpAuthCramMd5MechanismHelper* self= new (ELeave) CSmtpAuthCramMd5MechanismHelper(aSettings);

	CleanupStack::PushL(self);

	self->ConstructL();

	CleanupStack::Pop();	                                

	return self;

	}

CSmtpAuthCramMd5MechanismHelper::CSmtpAuthCramMd5MechanismHelper(const CSmtpSettings& aSettings) : CSmtpAuthMechanismHelper(aSettings)

	{

	}

void CSmtpAuthCramMd5MechanismHelper::ConstructL()

	{

	iMd5Hash = CMD5::NewL();

	}

CSmtpAuthCramMd5MechanismHelper::~CSmtpAuthCramMd5MechanismHelper()

	{

	delete iMd5Hash;

	}

void CSmtpAuthCramMd5MechanismHelper::GetNextClientMessageL(TDes8& aNextMessage)

	{

	iNextClientMessage.Zero();

	if(iInProgress)

		{

		HBufC8* authbuffer = HBufC8::NewMaxLC(KImMailMaxBufferSize);//? 

		TPtr8 authbufferptr = authbuffer->Des();

		HBufC8* authbuffer2 = HBufC8::NewMaxLC(KImMailMaxBufferSize);//? 

		TPtr8 authbufferptr2 = authbuffer2->Des();

		HBufC8* authbuffer3 = HBufC8::NewMaxLC(KImMailMaxBufferSize);//? 

		TPtr8 authbufferptr3 = authbuffer3->Des();

		authbufferptr = iLastServerMessage;

		authbufferptr.Delete(0,4); //remove 334 from the begining of server response

		iEncoder.Decode(authbufferptr,authbufferptr2);

		//timestamp info now in authbufferptr2

		authbufferptr.Zero();

		authbufferptr3.Zero();

		authbufferptr = iSettings.Password();

		authbufferptr3 = FormSharedSecret(authbufferptr);

		authbufferptr.Zero();

		authbufferptr = authbufferptr3;  //now authbufferptr and authbufferptr3 contain the shared secret null padded to 64 bytes.

		TInt i=0;

		for (i=0; i<KMd5BlockLength; i++) 

			{

			authbufferptr[i] ^= 0x36; //ipad

			authbufferptr3[i] ^= 0x5c; //opad

			}

		authbufferptr.Append(authbufferptr2);

    	iMd5Hash->Reset();                                                                                                                                                                                                                                                                                                                ;

		authbufferptr2 = iMd5Hash->Hash(authbufferptr);

		authbufferptr3.Append(authbufferptr2);

		authbufferptr.Zero();

		iMd5Hash->Reset();

		authbufferptr = iMd5Hash->Hash(authbufferptr3);

		// MD5 algorithm ALWAYS returns 16 bytes of data - which will be converted into

		// 32 characters; each byte represented by a 2 character hex representation, 

		// eg 255="ff"

		TBuf<32> hexHash; 

		for (i=0;i<16;i++)

			{

			hexHash.AppendNumFixedWidth(authbufferptr[i],EHex,2);

			}

		authbufferptr3.Zero();

		authbufferptr3.Append(iSettings.LoginName());

		authbufferptr3.Append(_L8(" "));

		authbufferptr3.Append(hexHash);

		iEncoder.Encode(authbufferptr3, iNextClientMessage);

		iNextClientMessage.Append(KSmtpCrLf);

		CleanupStack::PopAndDestroy(3);	// authbufferptr3 ,authbufferptr2, authbufferptr

		aNextMessage = iNextClientMessage;

		}

	else

		{

		iNextClientMessage.Append(KSmtpAuthCommand);

		iNextClientMessage.Append(KCramMD5Mechanism);

		iNextClientMessage.Append(KSmtpCrLf);

		iInProgress=ETrue;

		aNextMessage = iNextClientMessage;

		}

	}

TPtr8 CSmtpAuthCramMd5MechanismHelper::FormSharedSecret(TPtr8 aPassword)

	{

	TPtr8 secret = aPassword;

	if (aPassword.Length() <= KMd5BlockLength)

		{

		//pad up to 64 bytes with zeros

		secret.SetLength(64);

		TInt origLen = aPassword.Length();

		TInt lengthToFill = KMd5BlockLength-aPassword.Length();

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

			{

			secret[origLen+i]=0x00;

			}

		}

	else

		{

		//make shared secret the Digest of the password

		secret.Zero();

		iMd5Hash->Reset();

		secret = (iMd5Hash->Hash(aPassword));

		//do we need to call this function again now to pad out the 16 byte result?

		}

	return secret;

	}

void CSmtpAuthCramMd5MechanismHelper::SetLastServerMessageL(const TDesC8& aLastMessage, TBool /*aIsMultiLineResponse*/)

	{

	iLastServerMessage.Set(aLastMessage);

	}

//

//CSmtpAuthMechanismHelper factory function

//

GLDEF_C CSmtpAuthMechanismHelper* CreateSMTPAuthHelperL(CSmtpAuthMechanismHelper::TSmtpAuthProfileFlag aType, const CSmtpSettings& aSettings)

	{

	//Factory function that returns relevant Helper corresponding to aType

	switch(aType)

		{

	case CSmtpAuthMechanismHelper::EPlain:

		{

		CSmtpAuthMechanismHelper* helper;

		helper = new (ELeave) CSmtpAuthPlainMechanismHelper(aSettings);

		return helper;

		}

	case CSmtpAuthMechanismHelper::ELogin:

		{

		CSmtpAuthLoginMechanismHelper* smtpAuthLogin = CSmtpAuthLoginMechanismHelper::NewL(aSettings);

		return smtpAuthLogin;

		}

	case CSmtpAuthMechanismHelper::ECramMD5:

		{

		CSmtpAuthCramMd5MechanismHelper* smtpAuthCramMd5 = CSmtpAuthCramMd5MechanismHelper::NewL(aSettings);

		return smtpAuthCramMd5;

		}

	default:

	    User::Leave(KErrNotSupported); //gPanic(EImsmBadSmtpAuthProfile2);

		return NULL;

		}

	}