NISTZ256: owur'ize.

__owur'ize static methods to catch calling errors within the module.
Reviewed-by: NRich Salz <rsalz@openssl.org>

crypto/ec/ecp_nistz256.c

@@ -546,14 +546,14 @@ static void ecp_nistz256_mod_inverse(BN_ULONG r[P256_LIMBS],
  * ecp_nistz256_bignum_to_field_elem copies the contents of |in| to |out| and
  * returns one if it fits. Otherwise it returns zero.
  */
-static int ecp_nistz256_bignum_to_field_elem(BN_ULONG out[P256_LIMBS],
+__owur static int ecp_nistz256_bignum_to_field_elem(BN_ULONG out[P256_LIMBS],
                                                     const BIGNUM *in)
 {
     return bn_copy_words(out, in, P256_LIMBS);
 }
 
 /* r = sum(scalar[i]*point[i]) */
-static int ecp_nistz256_windowed_mul(const EC_GROUP *group,
+__owur static int ecp_nistz256_windowed_mul(const EC_GROUP *group,
                                             P256_POINT *r,
                                             const BIGNUM **scalar,
                                             const EC_POINT **point,
@@ -755,7 +755,7 @@ static int ecp_nistz256_is_affine_G(const EC_POINT *generator)
         is_one(bn_get_words(generator->Z));
 }
 
-static int ecp_nistz256_mult_precompute(EC_GROUP *group, BN_CTX *ctx)
+__owur static int ecp_nistz256_mult_precompute(EC_GROUP *group, BN_CTX *ctx)
 {
     /*
      * We precompute a table for a Booth encoded exponent (wNAF) based
@@ -1097,7 +1097,7 @@ static void ecp_nistz256_avx2_mul_g(P256_POINT *r,
 # endif
 #endif
 
-static int ecp_nistz256_set_from_affine(EC_POINT *out, const EC_GROUP *group,
+__owur static int ecp_nistz256_set_from_affine(EC_POINT *out, const EC_GROUP *group,
                                                const P256_POINT_AFFINE *in,
                                                BN_CTX *ctx)
 {
@@ -1130,7 +1130,7 @@ static int ecp_nistz256_set_from_affine(EC_POINT *out, const EC_GROUP *group,
 }
 
 /* r = scalar*G + sum(scalars[i]*points[i]) */
-static int ecp_nistz256_points_mul(const EC_GROUP *group,
+__owur static int ecp_nistz256_points_mul(const EC_GROUP *group,
                                           EC_POINT *r,
                                           const BIGNUM *scalar,
                                           size_t num,
@@ -1365,7 +1365,7 @@ err:
     return ret;
 }
 
-static int ecp_nistz256_get_affine(const EC_GROUP *group,
+__owur static int ecp_nistz256_get_affine(const EC_GROUP *group,
                                           const EC_POINT *point,
                                           BIGNUM *x, BIGNUM *y, BN_CTX *ctx)
 {