Commit 02fef916 authored by Matt Caswell's avatar Matt Caswell
Browse files

Fixed valgrind complaint due to BN_consttime_swap reading uninitialised data. 

This is actually ok for this function, but initialised to zero anyway if
PURIFY defined.

This does have the impact of masking any *real* unitialised data reads in bn though.

Patch based on approach suggested by Rich Salz.

PR#3415

(cherry picked from commit 77747e2d9a5573b1dbc15e247ce18c03374c760c)
parent 0b8cd5ac

crypto/bn/bn_lib.c

+9 −0
Original line number Diff line number Diff line
@@ -320,6 +320,15 @@ static BN_ULONG *bn_expand_internal(const BIGNUM *b, int words) 
		BNerr(BN_F_BN_EXPAND_INTERNAL,ERR_R_MALLOC_FAILURE);

		return(NULL);

		}

#ifdef PURIFY

	/* Valgrind complains in BN_consttime_swap because we process the whole

	 * array even if it's not initialised yet. This doesn't matter in that

	 * function - what's important is constant time operation (we're not

	 * actually going to use the data)

	*/

	memset(a, 0, sizeof(BN_ULONG)*words);

#endif



#if 1

	B=b->d;

	/* Check if the previous number needs to be copied */