Merge pull request #1935 from ImagicTheCat/hash-func-fix

Hash function fixes.

src/modules/data/HashFunction.cpp

@@ -50,6 +50,13 @@ inline uint64 rightrot(uint64 x, uint8 amount)
 	return (x >> amount) | (x << (64 - amount));
 }
 
+// Extend the value of `a` to make it a multiple of `n`.
+inline uint64 extend_multiple(uint64 a, uint64 n)
+{
+	uint64 r = a % n;
+	return r == 0 ? a : a + (n-r);
+}
+
 /**
  * The following implementation is based on the pseudocode provided by multiple
  * authors on wikipedia: https://en.wikipedia.org/wiki/MD5
@@ -79,25 +86,22 @@ public:
 		uint32 c0 = 0x98badcfe;
 		uint32 d0 = 0x10325476;
 
-		//Do the required padding (MD5, SHA1 and SHA2 use the same padding)
-		uint64 paddedLength = length + 1; //Consider the appended bit
-		if (paddedLength % 64 < 56)
-			paddedLength += 56 - paddedLength % 64;
-		if (paddedLength % 64 > 56)
-			paddedLength += 120 - paddedLength % 64;
+		// Compute final padded length, accounting for the appended bit (byte) and size
+		uint64 paddedLength = extend_multiple(length + 1 + 8, 64);
 
-		uint8 *padded = new uint8[paddedLength + 8];
+		uint32 *padded = new uint32[paddedLength / 4];
 		memcpy(padded, input, length);
-		memset(padded + length, 0, paddedLength - length);
-		padded[length] = 0x80;
+		memset(((uint8*)padded) + length, 0, paddedLength - length);
+		*(((uint8*)padded) + length) = 0x80; // append bit
 
-		//Now we need the length in bits
-		*((uint64*) &padded[paddedLength]) = length * 8;
-		paddedLength += 8;
+		// Append length in bits
+		uint64 bit_length = length * 8;
+		memcpy(((uint8*)padded) + paddedLength - 8, &bit_length, 8);
 
-		for (uint64 i = 0; i < paddedLength; i += 64)
+		// Process chunks
+		for (uint64 i = 0; i < paddedLength/4; i += 16)
 		{
-			uint32 *chunk = (uint32*) &padded[i];
+			uint32 *chunk = &padded[i];
 
 			uint32 A = a0;
 			uint32 B = b0;
@@ -200,29 +204,25 @@ public:
 			0x67452301, 0xEFCDAB89, 0x98BADCFE, 0x10325476, 0xC3D2E1F0
 		};
 
-		//Do the required padding (MD5, SHA1 and SHA2 use the same padding)
-		uint64 paddedLength = length + 1; //Consider the appended bit
-		if (paddedLength % 64 < 56)
-			paddedLength += 56 - paddedLength % 64;
-		if (paddedLength % 64 > 56)
-			paddedLength += 120 - paddedLength % 64;
+		// Compute final padded length, accounting for the appended bit (byte) and size
+		uint64 paddedLength = extend_multiple(length + 1 + 8, 64);
 
-		uint8 *padded = new uint8[paddedLength + 8];
+		uint32 *padded = new uint32[paddedLength / 4];
 		memcpy(padded, input, length);
-		memset(padded + length, 0, paddedLength - length);
-		padded[length] = 0x80;
+		memset(((uint8*)padded) + length, 0, paddedLength - length);
+		*(((uint8*)padded) + length) = 0x80; // append bit
 
-		// Now we need the length in bits (big endian)
-		length *= 8;
-		for (int i = 0; i < 8; ++i, ++paddedLength)
-			padded[paddedLength] = (length >> (56 - i * 8)) & 0xFF;
+		// Append length in bits (big endian)
+		uint64 bit_length = length * 8;
+		for (int i = 0; i < 8; ++i)
+			*(((uint8*)padded) + (paddedLength - 8 + i)) = (bit_length >> (56 - i * 8)) & 0xFF;
 
 		// Allocate our extended words
 		uint32 words[80];
 
-		for (uint64 i = 0; i < paddedLength; i += 64)
+		for (uint64 i = 0; i < paddedLength/4; i += 16)
 		{
-			uint32 *chunk = (uint32*) &padded[i];
+			uint32 *chunk = &padded[i];
 			for (int j = 0; j < 16; j++)
 			{
 				char *c = (char*) &words[j];
@@ -303,22 +303,18 @@ public:
 		if (!isSupported(function))
 			throw love::Exception("Hash function not supported by SHA-224/SHA-256 implementation");
 
-		//Do the required padding (MD5, SHA1 and SHA2 use the same padding)
-		uint64 paddedLength = length + 1; //Consider the appended bit
-		if (paddedLength % 64 < 56)
-			paddedLength += 56 - paddedLength % 64;
-		if (paddedLength % 64 > 56)
-			paddedLength += 120 - paddedLength % 64;
+		// Compute final padded length, accounting for the appended bit (byte) and size
+		uint64 paddedLength = extend_multiple(length + 1 + 8, 64);
 
-		uint8 *padded = new uint8[paddedLength + 8];
+		uint32 *padded = new uint32[paddedLength / 4];
 		memcpy(padded, input, length);
-		memset(padded + length, 0, paddedLength - length);
-		padded[length] = 0x80;
+		memset(((uint8*)padded) + length, 0, paddedLength - length);
+		*(((uint8*)padded) + length) = 0x80; // append bit
 
-		// Now we need the length in bits (big endian)
-		length *= 8;
-		for (int i = 0; i < 8; ++i, ++paddedLength)
-			padded[paddedLength] = (length >> (56 - i * 8)) & 0xFF;
+		// Append length in bits (big endian)
+		uint64 bit_length = length * 8;
+		for (int i = 0; i < 8; ++i)
+			*(((uint8*)padded) + (paddedLength - 8 + i)) = (bit_length >> (56 - i * 8)) & 0xFF;
 
 		uint32 intermediate[8];
 		if (function == FUNCTION_SHA224)
@@ -329,9 +325,9 @@ public:
 		// Allocate our extended words
 		uint32 words[64];
 
-		for (uint64 i = 0; i < paddedLength; i += 64)
+		for (uint64 i = 0; i < paddedLength/4; i += 16)
 		{
-			uint32 *chunk = (uint32*) &padded[i];
+			uint32 *chunk = &padded[i];
 			for (int j = 0; j < 16; j++)
 			{
 				char *c = (char*) &words[j];
@@ -459,31 +455,26 @@ public:
 		else
 			memcpy(intermediates, initial512, sizeof(intermediates));
 
-		//Do the required padding
-		uint64 paddedLength = length + 1; //Consider the appended bit
-		if (paddedLength % 128 < 112)
-			paddedLength += 112 - paddedLength % 128;
-		if (paddedLength % 128 > 112)
-			paddedLength += 240 - paddedLength % 128;
+		// Compute final padded length, accounting for the appended bit (byte) and size
+		uint64 paddedLength = extend_multiple(length + 1 + 16, 128);
 
-		uint8 *padded = new uint8[paddedLength + 16];
-		paddedLength += 8;
+		uint64 *padded = new uint64[paddedLength / 8];
 		memcpy(padded, input, length);
-		memset(padded + length, 0, paddedLength - length);
-		padded[length] = 0x80;
+		memset(((uint8*)padded) + length, 0, paddedLength - length);
+		*(((uint8*)padded) + length) = 0x80; // append bit
 
-		// Now we need the length in bits (big endian), note we only write a 64-bit int, so
+		// Append length in bits (big endian), note we only write a 64-bit int, so
 		// we have filled the first 8 bytes with zeroes
-		length *= 8;
-		for (int i = 0; i < 8; ++i, ++paddedLength)
-			padded[paddedLength] = (length >> (56 - i * 8)) & 0xFF;
+		uint64 bit_length = length * 8;
+		for (int i = 0; i < 8; ++i)
+			*(((uint8*)padded) + (paddedLength - 8 + i)) = (bit_length >> (56 - i * 8)) & 0xFF;
 
 		// Allocate our extended words
 		uint64 words[80];
 
-		for (uint64 i = 0; i < paddedLength; i += 128)
+		for (uint64 i = 0; i < paddedLength/8; i += 16)
 		{
-			uint64 *chunk = (uint64*) &padded[i];
+			uint64 *chunk = &padded[i];
 			for (int j = 0; j < 16; ++j)
 			{
 				char *c = (char*) &words[j];