From 97e0de7f2cfb7bc5dc7a47959f6ec4c7c28eb8ad Mon Sep 17 00:00:00 2001
From: tb <tb@openbsd.org>
Date: Tue, 22 Oct 2024 12:06:08 +0000
Subject: [PATCH] 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
---
 lib/libcrypto/ec/ec_asn1.c  |  4 ++--
 lib/libcrypto/ec/ec_lib.c   | 14 +++++++++++---
 lib/libcrypto/ec/ec_local.h |  3 ++-
 lib/libcrypto/ec/eck_prn.c  |  4 ++--
 4 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/lib/libcrypto/ec/ec_asn1.c b/lib/libcrypto/ec/ec_asn1.c
index 6e97d43c5c2..60225f48f9f 100644
--- a/lib/libcrypto/ec/ec_asn1.c
+++ b/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/lib/libcrypto/ec/ec_lib.c b/lib/libcrypto/ec/ec_lib.c
index 1918d0ba527..6da20266622 100644
--- a/lib/libcrypto/ec/ec_lib.c
+++ b/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/lib/libcrypto/ec/ec_local.h b/lib/libcrypto/ec/ec_local.h
index b837e291f7c..4786f8520b8 100644
--- a/lib/libcrypto/ec/ec_local.h
+++ b/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/lib/libcrypto/ec/eck_prn.c b/lib/libcrypto/ec/eck_prn.c
index 2798d53d0c6..847dc0a159a 100644
--- a/lib/libcrypto/ec/eck_prn.c
+++ b/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;
 
-- 
2.20.1