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os/security/crypto/weakcrypto/source/padding/pkcs7.cpp
author sl
Tue, 10 Jun 2014 14:32:02 +0200
changeset 1 260cb5ec6c19
permissions -rw-r--r--
Update contrib. 
     1 /*

     2 * Copyright (c) 2003-2009 Nokia Corporation and/or its subsidiary(-ies).

     3 * All rights reserved.

     4 * This component and the accompanying materials are made available

     5 * under the terms of the License "Eclipse Public License v1.0"

     6 * which accompanies this distribution, and is available

     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".

     8 *

     9 * Initial Contributors:

    10 * Nokia Corporation - initial contribution.

    11 *

    12 * Contributors:

    13 *

    14 * Description: 

    15 *

    16 */

    17 

    18 

    19 #include <e32base.h>

    20 #include <padding.h>

    21 #include <securityerr.h>

    22 #include <cryptopanic.h>

    23 

    24 /* CPaddingPKCS7 */

    25 EXPORT_C CPaddingPKCS7* CPaddingPKCS7::NewL(TInt aBlockBytes)

    26 	{

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

    28 	return new(ELeave)CPaddingPKCS7(aBlockBytes);

    29 	}

    30 

    31 EXPORT_C CPaddingPKCS7* CPaddingPKCS7::NewLC(TInt aBlockBytes)

    32 	{

    33 	CPaddingPKCS7* self = CPaddingPKCS7::NewL(aBlockBytes);

    34 	CleanupStack::PushL(self);

    35 	return self;

    36 	}

    37 

    38 EXPORT_C CPaddingPKCS7::CPaddingPKCS7(TInt aBlockBytes):CPadding(aBlockBytes)

    39 	{

    40 	}

    41 

    42 void CPaddingPKCS7::DoPadL(const TDesC8& aInput,TDes8& aOutput)

    43 	{

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

    45 	aOutput.Append(aInput);

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

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

    48 		{

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

    50 		}

    51 	}

    52 

    53 void CPaddingPKCS7::UnPadL(const TDesC8& aInput,TDes8& aOutput)

    54 	{

    55 	TUint inputLen = aInput.Length();

    56  	TUint paddingLen = (TUint)(aInput[inputLen - 1]);

    57 

    58 	if (paddingLen > inputLen)

    59  		{

    60  		User::Leave(KErrInvalidPadding);

    61  		}

    62    

    63 	TInt outlen = aInput.Length() - paddingLen;

    64 

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

    66 

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

    68 	for (TInt i=outlen;i<inputLen;i++)

    69 		{

    70 		//All padding bytes must equal the length of padding expected

    71 		if (aInput[i]!=paddingLen)

    72 			{

    73 			User::Leave(KErrInvalidPadding);

    74 			}

    75 		}

    76 	}

    77 

    78 TInt CPaddingPKCS7::MinPaddingLength(void) const

    79 	{

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

    81 	return 1;

    82 	}

    83 

    84 TInt CPaddingPKCS7::MaxPaddedLength(TInt aInputBytes) const

    85 	{

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

    87 	return padBytes + aInputBytes;

    88 	}

    89
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