Clear Valgrind finding in IncrementCounterByOne

The single buffer IncrementCounterByOne generated a Valgrind finding on ARM. This commit uses the same pattern for both overloads in case Valgrind wants to fire on the two-buffer version.

1 files changed, 18 insertions, 6 deletions

diff --git a/misc.h b/misc.h
index d836aaa2..2cdabfbe 100644
--- a/misc.h
+++ b/misc.h
@@ -1225,10 +1225,12 @@ CRYPTOPP_DLL void CRYPTOPP_API CallNewHandler();
 /// \note The function is not constant time because it stops processing when the carry is 0.

 inline void IncrementCounterByOne(byte *inout, unsigned int size)

 {

+	CRYPTOPP_ASSERT(inout != NULLPTR);

+

 	unsigned int carry=1;

 	while (carry && size != 0)

 	{

-		// On wrap inout[n] equals 0

+		// On carry inout[n] equals 0

 		carry = ! ++inout[size-1];

 		size--;

 	}

@@ -1243,12 +1245,22 @@ inline void IncrementCounterByOne(byte *inout, unsigned int size)
 /// \details The function is close to near-constant time because it operates on all the bytes in the blocks.

 inline void IncrementCounterByOne(byte *output, const byte *input, unsigned int size)

 {

-	CRYPTOPP_ASSERT(output != NULLPTR); CRYPTOPP_ASSERT(input != NULLPTR); CRYPTOPP_ASSERT(size < INT_MAX);

+	CRYPTOPP_ASSERT(output != NULLPTR);

+	CRYPTOPP_ASSERT(input != NULLPTR);

+

+	unsigned int carry=1;

+	while (carry && size != 0)

+	{

+		// On carry output[n] equals 0

+		carry = ! (output[size-1] = input[size-1] + 1);

+		size--;

+	}

 

-	int i, carry;

-	for (i=int(size-1), carry=1; i>=0 && carry; i--)

-		carry = ((output[i] = input[i]+1) == 0);

-	memcpy_s(output, size, input, size_t(i)+1);

+	while (size != 0)

+	{

+		output[size-1] = input[size-1];

+		size--;

+	}

 }

 

 /// \brief Performs a branchless swap of values a and b if condition c is true