Switch ec_asn1_group2parameters() to get0_{order,cofactor}()

These are more ergonomic, result in more readable code, avoid a copy and
we no longer ignore a possible memory allocation error due to API misdesign
and bad code.

ok jsing

diff --git a/lib/libcrypto/ec/ec_asn1.c b/lib/libcrypto/ec/ec_asn1.c
index 0fe187a..0260960 100644 (file)
--- a/lib/libcrypto/ec/ec_asn1.c
+++ b/lib/libcrypto/ec/ec_asn1.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ec_asn1.c,v 1.72 2024/10/14 18:17:11 tb Exp $ */
+/* $OpenBSD: ec_asn1.c,v 1.73 2024/10/15 06:35:59 tb Exp $ */
 /*
  * Written by Nils Larsch for the OpenSSL project.
  */
@@ -695,15 +695,11 @@ ec_asn1_group2parameters(const EC_GROUP *group)
        int ok = 0;
        size_t len = 0;
        ECPARAMETERS *ret = NULL;
-       BIGNUM *tmp = NULL;
+       const BIGNUM *order, *cofactor;
        unsigned char *buffer = NULL;
        const EC_POINT *point = NULL;
        point_conversion_form_t form;
 
-       if ((tmp = BN_new()) == NULL) {
-               ECerror(ERR_R_MALLOC_FAILURE);
-               goto err;
-       }
        if ((ret = ECPARAMETERS_new()) == NULL) {
                ECerror(ERR_R_MALLOC_FAILURE);
                goto err;
@@ -750,19 +746,27 @@ ec_asn1_group2parameters(const EC_GROUP *group)
                ECerror(ERR_R_ASN1_LIB);
                goto err;
        }
-       if (!EC_GROUP_get_order(group, tmp, NULL)) {
+       if ((order = EC_GROUP_get0_order(group)) == NULL) {
+               ECerror(ERR_R_EC_LIB);
+               goto err;
+       }
+       if (BN_is_zero(order)) {
                ECerror(ERR_R_EC_LIB);
                goto err;
        }
        ASN1_INTEGER_free(ret->order);
-       if ((ret->order = BN_to_ASN1_INTEGER(tmp, NULL)) == NULL) {
+       if ((ret->order = BN_to_ASN1_INTEGER(order, NULL)) == NULL) {
                ECerror(ERR_R_ASN1_LIB);
                goto err;
        }
        ASN1_INTEGER_free(ret->cofactor);
        ret->cofactor = NULL;
-       if (EC_GROUP_get_cofactor(group, tmp, NULL)) {
-               if ((ret->cofactor = BN_to_ASN1_INTEGER(tmp, NULL)) == NULL) {
+       if ((cofactor = EC_GROUP_get0_cofactor(group)) == NULL) {
+               ECerror(ERR_R_EC_LIB);
+               goto err;
+       }
+       if (!BN_is_zero(cofactor)) {
+               if ((ret->cofactor = BN_to_ASN1_INTEGER(cofactor, NULL)) == NULL) {
                        ECerror(ERR_R_ASN1_LIB);
                        goto err;
                }
@@ -774,7 +778,6 @@ ec_asn1_group2parameters(const EC_GROUP *group)
                ECPARAMETERS_free(ret);
                ret = NULL;
        }
-       BN_free(tmp);
        free(buffer);
        return (ret);
 }