Commit eca5174b authored by Andy Polyakov's avatar Andy Polyakov
Browse files

ec/ecp_nistz256.c: get is_one on 32-bit platforms right. 



Thanks to Brian Smith for reporting this.

Reviewed-by: default avatarRich Salz <rsalz@openssl.org>
parent bc894569

crypto/ec/ecp_nistz256.c

+22 −15
Original line number Diff line number Diff line
@@ -205,10 +205,12 @@ static BN_ULONG is_equal(const BN_ULONG a[P256_LIMBS], 
    return is_zero(res);

}



static BN_ULONG is_one(const BN_ULONG a[P256_LIMBS])

static BN_ULONG is_one(const BIGNUM *z)

{

    BN_ULONG res;

    BN_ULONG res = 0;

    BN_ULONG *a = z->d;



    if (z->top == (P256_LIMBS - P256_LIMBS / 8)) {

        res = a[0] ^ ONE[0];

        res |= a[1] ^ ONE[1];

        res |= a[2] ^ ONE[2];
@@ -217,9 +219,15 @@ static BN_ULONG is_one(const BN_ULONG a[P256_LIMBS]) 
            res |= a[4] ^ ONE[4];

            res |= a[5] ^ ONE[5];

            res |= a[6] ^ ONE[6];

            /*

             * no check for a[7] (being zero) on 32-bit platforms,

             * because value of "one" takes only 7 limbs.

             */

        }

        res = is_zero(res);

    }



    return is_zero(res);

    return res;

}



static int ecp_nistz256_set_words(BIGNUM *a, BN_ULONG words[P256_LIMBS])
@@ -741,9 +749,8 @@ static int ecp_nistz256_is_affine_G(const EC_POINT *generator) 
{

    return (generator->X.top == P256_LIMBS) &&

        (generator->Y.top == P256_LIMBS) &&

        (generator->Z.top == (P256_LIMBS - P256_LIMBS / 8)) &&

        is_equal(generator->X.d, def_xG) &&

        is_equal(generator->Y.d, def_yG) && is_one(generator->Z.d);

        is_equal(generator->Y.d, def_yG) && is_one(&generator->Z);

}



static int ecp_nistz256_mult_precompute(EC_GROUP *group, BN_CTX *ctx)
@@ -1331,7 +1338,7 @@ static int ecp_nistz256_points_mul(const EC_GROUP *group, 
        !ecp_nistz256_set_words(&r->Z, p.p.Z)) {

        goto err;

    }

    r->Z_is_one = is_one(p.p.Z) & 1;

    r->Z_is_one = is_one(&r->Z) & 1;



    ret = 1;