Use aligned buffer for CMAC

1 files changed, 16 insertions, 2 deletions

diff --git a/cmac.cpp b/cmac.cpp
index 1b56662d..367a778c 100644
--- a/cmac.cpp
+++ b/cmac.cpp
@@ -77,7 +77,8 @@ void CMAC_Base::Update(const byte *input, size_t length)
 		return;

 

 	BlockCipher &cipher = AccessCipher();

-	unsigned int blockSize = cipher.BlockSize();

+	const unsigned int blockSize = cipher.BlockSize();

+	const unsigned int alignment = cipher.OptimalDataAlignment();

 

 	if (m_counter > 0)

 	{

@@ -100,7 +101,20 @@ void CMAC_Base::Update(const byte *input, size_t length)
 	if (length > blockSize)

 	{

 		CRYPTOPP_ASSERT(m_counter == 0);

-		size_t leftOver = 1 + cipher.AdvancedProcessBlocks(m_reg, input, m_reg, length-1, BlockTransformation::BT_DontIncrementInOutPointers|BlockTransformation::BT_XorInput);

+		const byte* is = input;  // m_reg is always aligned

+

+		AlignedSecByteBlock i;

+		if (!IsAlignedOn(input, alignment))

+		{

+			i.Assign(input, length);

+			is = i.begin();

+		}

+

+		// size_t leftOver = 1 + cipher.AdvancedProcessBlocks(m_reg, input, m_reg, length-1,

+		//   BlockTransformation::BT_DontIncrementInOutPointers|BlockTransformation::BT_XorInput);

+		const int flags = BlockTransformation::BT_DontIncrementInOutPointers|BlockTransformation::BT_XorInput;

+		size_t leftOver = 1 + cipher.AdvancedProcessBlocks(m_reg, is, m_reg, length-1, flags);

+

 		input += (length - leftOver);

 		length = leftOver;

 	}