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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.
pull/853/head
Jeffrey Walton 2019-05-25 19:49:49 -04:00
parent ca11105a40
commit 9a3c1e351d
No known key found for this signature in database
GPG Key ID: B36AB348921B1838
1 changed files with 18 additions and 6 deletions
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24
misc.h
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@ -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. /// \note The function is not constant time because it stops processing when the carry is 0.
inline void IncrementCounterByOne(byte *inout, unsigned int size) inline void IncrementCounterByOne(byte *inout, unsigned int size)
{ {
CRYPTOPP_ASSERT(inout != NULLPTR);
unsigned int carry=1; unsigned int carry=1;
while (carry && size != 0) while (carry && size != 0)
{ {
// On wrap inout[n] equals 0 // On carry inout[n] equals 0
carry = ! ++inout[size-1]; carry = ! ++inout[size-1];
size--; 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. /// \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) 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);
int i, carry; unsigned int carry=1;
for (i=int(size-1), carry=1; i>=0 && carry; i--) while (carry && size != 0)
carry = ((output[i] = input[i]+1) == 0); {
memcpy_s(output, size, input, size_t(i)+1); // On carry output[n] equals 0
carry = ! (output[size-1] = input[size-1] + 1);
size--;
}
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 /// \brief Performs a branchless swap of values a and b if condition c is true