First Commit

externals/cryptopp/cmac.cpp

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+// cmac.cpp - originally written and placed in the public domain by Wei Dai
+
+#include "pch.h"
+
+#ifndef CRYPTOPP_IMPORTS
+
+#include "cmac.h"
+#include "misc.h"
+
+ANONYMOUS_NAMESPACE_BEGIN
+
+using CryptoPP::byte;
+using CryptoPP::IsPowerOf2;
+
+void MulU(byte *k, unsigned int len)
+{
+	byte carry = 0;
+	for (int i=len-1; i>=1; i-=2)
+	{
+		byte carry2 = k[i] >> 7;
+		k[i] += k[i] + carry;
+		carry = k[i-1] >> 7;
+		k[i-1] += k[i-1] + carry2;
+	}
+
+#ifndef CRYPTOPP_CMAC_WIDE_BLOCK_CIPHERS
+	CRYPTOPP_ASSERT(len == 16);
+
+	if (carry)
+	{
+		k[15] ^= 0x87;
+		return;
+	}
+#else
+	CRYPTOPP_ASSERT(IsPowerOf2(len));
+	CRYPTOPP_ASSERT(len >= 8);
+	CRYPTOPP_ASSERT(len <= 128);
+
+	if (carry)
+	{
+		switch (len)
+		{
+		case 8:
+			k[7] ^= 0x1b;
+			break;
+		case 16:
+			k[15] ^= 0x87;
+			break;
+		case 32:
+			// https://crypto.stackexchange.com/q/9815/10496
+			// Polynomial x^256 + x^10 + x^5 + x^2 + 1
+			k[30] ^= 4;
+			k[31] ^= 0x25;
+			break;
+		case 64:
+			// https://crypto.stackexchange.com/q/9815/10496
+			// Polynomial x^512 + x^8 + x^5 + x^2 + 1
+			k[62] ^= 1;
+			k[63] ^= 0x25;
+			break;
+		case 128:
+			// https://crypto.stackexchange.com/q/9815/10496
+			// Polynomial x^1024 + x^19 + x^6 + x + 1
+			k[125] ^= 8;
+			k[126] ^= 0x00;
+			k[127] ^= 0x43;
+			break;
+		default:
+			CRYPTOPP_ASSERT(0);
+		}
+	}
+#endif  // CRYPTOPP_CMAC_WIDE_BLOCK_CIPHERS
+}
+
+ANONYMOUS_NAMESPACE_END
+
+NAMESPACE_BEGIN(CryptoPP)
+
+void CMAC_Base::UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs &params)
+{
+	BlockCipher &cipher = AccessCipher();
+	cipher.SetKey(key, length, params);
+
+	unsigned int blockSize = cipher.BlockSize();
+	m_reg.CleanNew(3*blockSize);
+	m_counter = 0;
+
+	cipher.ProcessBlock(m_reg, m_reg+blockSize);
+	MulU(m_reg+blockSize, blockSize);
+	std::memcpy(m_reg+2*blockSize, m_reg+blockSize, blockSize);
+	MulU(m_reg+2*blockSize, blockSize);
+}
+
+void CMAC_Base::Update(const byte *input, size_t length)
+{
+	CRYPTOPP_ASSERT((input && length) || !(input || length));
+	if (!length)
+		return;
+
+	BlockCipher &cipher = AccessCipher();
+	unsigned int blockSize = cipher.BlockSize();
+
+	if (m_counter > 0)
+	{
+		const unsigned int len = UnsignedMin(blockSize - m_counter, length);
+		if (len)
+		{
+			xorbuf(m_reg+m_counter, input, len);
+			length -= len;
+			input += len;
+			m_counter += len;
+		}
+
+		if (m_counter == blockSize && length > 0)
+		{
+			cipher.ProcessBlock(m_reg);
+			m_counter = 0;
+		}
+	}
+
+	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);
+		input += (length - leftOver);
+		length = leftOver;
+	}
+
+	if (length > 0)
+	{
+		CRYPTOPP_ASSERT(m_counter + length <= blockSize);
+		xorbuf(m_reg+m_counter, input, length);
+		m_counter += (unsigned int)length;
+	}
+
+	CRYPTOPP_ASSERT(m_counter > 0);
+}
+
+void CMAC_Base::TruncatedFinal(byte *mac, size_t size)
+{
+	ThrowIfInvalidTruncatedSize(size);
+
+	BlockCipher &cipher = AccessCipher();
+	unsigned int blockSize = cipher.BlockSize();
+
+	if (m_counter < blockSize)
+	{
+		m_reg[m_counter] ^= 0x80;
+		cipher.AdvancedProcessBlocks(m_reg, m_reg+2*blockSize, m_reg, blockSize, BlockTransformation::BT_DontIncrementInOutPointers|BlockTransformation::BT_XorInput);
+	}
+	else
+		cipher.AdvancedProcessBlocks(m_reg, m_reg+blockSize, m_reg, blockSize, BlockTransformation::BT_DontIncrementInOutPointers|BlockTransformation::BT_XorInput);
+
+	// UBsan finding
+	if (mac)
+		std::memcpy(mac, m_reg, size);
+
+	m_counter = 0;
+	std::memset(m_reg, 0, blockSize);
+}
+
+NAMESPACE_END
+
+#endif