Commit eb1f1b0a authored by Bodo Möller's avatar Bodo Möller
Browse files

Fix BN_kronecker so that it works correctly if 'a' is negative 

(we need the two's complement of BN_lsw then).
parent a9376dbf

crypto/bn/bn_kron.c

+2 −2
Original line number Diff line number Diff line
@@ -65,7 +65,7 @@ 
int BN_kronecker(const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)

	{

	int i;

	int ret;

	int ret = -2; /* avoid 'uninitialized' warning */

	int err = 0;

	BIGNUM *A, *B, *tmp;

	/* In 'tab', only odd-indexed entries are relevant:
@@ -165,7 +165,7 @@ int BN_kronecker(const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx) 
	

		/* Cohen's step 4: */

		/* multiply 'ret' by  $(-1)^{(A-1)(B-1)/4}$ */

		if (BN_lsw(A) & BN_lsw(B) & 2)

		if ((A->neg ? ~BN_lsw(A) : BN_lsw(A)) & BN_lsw(B) & 2)

			ret = -ret;

		

		/* (A, B) := (B mod |A|, |A|) */

crypto/bn/bntest.c

+2 −2
Original line number Diff line number Diff line
@@ -949,7 +949,7 @@ int test_kron(BIO *bp, BN_CTX *ctx) 
	for (i = 0; i < num0; i++)

		{

		if (!BN_rand(a, 512, 0, 0)) goto err;

		if (!BN_nnmod(a, a, b, ctx)) goto err;

		a->neg = rand_neg();



		/* r := (b-1)/2  (note that b is odd) */

		if (!BN_copy(r, b)) goto err;