Commit 2e929e53 authored by Andy Polyakov's avatar Andy Polyakov
Browse files

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 5a7ad1f0

crypto/ec/ecp_nistz256.c

+22 −15
Original line number Diff line number Diff line
@@ -212,10 +212,12 @@ 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 = bn_get_words(z);



    if (bn_get_top(z) == (P256_LIMBS - P256_LIMBS / 8)) {

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

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

        res |= a[2] ^ ONE[2];
@@ -224,9 +226,15 @@ 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;

}



#ifndef ECP_NISTZ256_REFERENCE_IMPLEMENTATION
@@ -752,10 +760,9 @@ static int ecp_nistz256_is_affine_G(const EC_POINT *generator) 
{

    return (bn_get_top(generator->X) == P256_LIMBS) &&

        (bn_get_top(generator->Y) == P256_LIMBS) &&

        (bn_get_top(generator->Z) == (P256_LIMBS - P256_LIMBS / 8)) &&

        is_equal(bn_get_words(generator->X), def_xG) &&

        is_equal(bn_get_words(generator->Y), def_yG) &&

        is_one(bn_get_words(generator->Z));

        is_one(generator->Z);

}



__owur static int ecp_nistz256_mult_precompute(EC_GROUP *group, BN_CTX *ctx)
@@ -1332,7 +1339,7 @@ __owur static int ecp_nistz256_points_mul(const EC_GROUP *group, 
        !bn_set_words(r->Z, p.p.Z, P256_LIMBS)) {

        goto err;

    }

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

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



    ret = 1;