Provide and use ec_group_get_field_type()

All internal uses of EC_METHOD_get_field_type() and EC_GROUP_method_of()
are chained together. Implement this as a single API call that takes a
group and use it throughout. Gets rid of another eyesore in this part of
the tree. Not that there will be a shortage of eyesores anytime soon...

ok jsing

4 files changed, 17 insertions, 8 deletions

diff --git a/src/lib/libcrypto/ec/ec_asn1.c b/src/lib/libcrypto/ec/ec_asn1.c
index 6e97d43c5c..60225f48f9 100644
--- a/src/lib/libcrypto/ec/ec_asn1.c
+++ b/src/lib/libcrypto/ec/ec_asn1.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ec_asn1.c,v 1.76 2024/10/20 10:48:29 tb Exp $ */
+/* $OpenBSD: ec_asn1.c,v 1.77 2024/10/22 12:06:08 tb Exp $ */
 /*
  * Written by Nils Larsch for the OpenSSL project.
  */
@@ -570,7 +570,7 @@ ec_asn1_group2fieldid(const EC_GROUP *group, X9_62_FIELDID *field)
         if (group == NULL || field == NULL)
                 goto err;
 
-        nid = EC_METHOD_get_field_type(EC_GROUP_method_of(group));
+        nid = ec_group_get_field_type(group);
         if (nid == NID_X9_62_characteristic_two_field) {
                 ECerror(EC_R_GF2M_NOT_SUPPORTED);
                 goto err;
diff --git a/src/lib/libcrypto/ec/ec_lib.c b/src/lib/libcrypto/ec/ec_lib.c
index 1918d0ba52..6da2026662 100644
--- a/src/lib/libcrypto/ec/ec_lib.c
+++ b/src/lib/libcrypto/ec/ec_lib.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ec_lib.c,v 1.72 2024/10/19 08:29:40 tb Exp $ */
+/* $OpenBSD: ec_lib.c,v 1.73 2024/10/22 12:06:08 tb Exp $ */
 /*
  * Originally written by Bodo Moeller for the OpenSSL project.
  */
@@ -219,6 +219,15 @@ EC_METHOD_get_field_type(const EC_METHOD *meth)
 }
 LCRYPTO_ALIAS(EC_METHOD_get_field_type);
 
+int
+ec_group_get_field_type(const EC_GROUP *group)
+{
+        if (group == NULL || group->meth == NULL)
+                return NID_undef;
+
+        return group->meth->field_type;
+}
+
 /*
  * If there is a user-provided cofactor, sanity check and use it. Otherwise
  * try computing the cofactor from generator order n and field cardinality q.
@@ -663,8 +672,7 @@ EC_GROUP_cmp(const EC_GROUP *a, const EC_GROUP *b, BN_CTX *ctx)
         BN_CTX *ctx_new = NULL;
 
         /* compare the field types */
-        if (EC_METHOD_get_field_type(EC_GROUP_method_of(a)) !=
-            EC_METHOD_get_field_type(EC_GROUP_method_of(b)))
+        if (ec_group_get_field_type(a) != ec_group_get_field_type(b))
                 return 1;
         /* compare the curve name (if present in both) */
         if (EC_GROUP_get_curve_name(a) && EC_GROUP_get_curve_name(b) &&
diff --git a/src/lib/libcrypto/ec/ec_local.h b/src/lib/libcrypto/ec/ec_local.h
index b837e291f7..4786f8520b 100644
--- a/src/lib/libcrypto/ec/ec_local.h
+++ b/src/lib/libcrypto/ec/ec_local.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: ec_local.h,v 1.30 2024/10/18 17:27:07 tb Exp $ */
+/* $OpenBSD: ec_local.h,v 1.31 2024/10/22 12:06:08 tb Exp $ */
 /*
  * Originally written by Bodo Moeller for the OpenSSL project.
  */
@@ -356,6 +356,7 @@ int EC_POINT_get_Jprojective_coordinates(const EC_GROUP *group,
     const EC_POINT *p, BIGNUM *x, BIGNUM *y, BIGNUM *z, BN_CTX *ctx);
 
 int ec_group_is_builtin_curve(const EC_GROUP *group);
+int ec_group_get_field_type(const EC_GROUP *group);
 
 /* Public API in OpenSSL */
 const BIGNUM *EC_GROUP_get0_cofactor(const EC_GROUP *group);
diff --git a/src/lib/libcrypto/ec/eck_prn.c b/src/lib/libcrypto/ec/eck_prn.c
index 2798d53d0c..847dc0a159 100644
--- a/src/lib/libcrypto/ec/eck_prn.c
+++ b/src/lib/libcrypto/ec/eck_prn.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: eck_prn.c,v 1.30 2023/11/21 22:05:33 tb Exp $ */
+/* $OpenBSD: eck_prn.c,v 1.31 2024/10/22 12:06:08 tb Exp $ */
 /*
  * Written by Nils Larsch for the OpenSSL project.
  */
@@ -258,7 +258,7 @@ ecpk_print_explicit_parameters(BIO *bp, const EC_GROUP *group, int off)
         if (!BIO_indent(bp, off, 128))
                 goto err;
 
-        nid = EC_METHOD_get_field_type(EC_GROUP_method_of(group));
+        nid = ec_group_get_field_type(group);
         if (BIO_printf(bp, "Field Type: %s\n", OBJ_nid2sn(nid)) <= 0)
                 goto err;