Add nid to EC_POINT for compat checking

It is annoying that an EC_POINT does not really know on what EC_GROUP it
lives. Adding a refcount to EC_GROUP is slightly tricky, so instead use
a nid which we will know unless the group was constructed by hand.

ok jsing kenjiro

2 files changed, 6 insertions, 2 deletions

diff --git a/src/lib/libcrypto/ec/ec_lib.c b/src/lib/libcrypto/ec/ec_lib.c
index 36f42ecc05..b31c132a77 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 1.126 2025/08/02 15:47:27 jsing Exp $ */
+/* $OpenBSD: ec_lib.c,v 1.127 2025/12/26 18:41:05 tb Exp $ */
 /*
  * Originally written by Bodo Moeller for the OpenSSL project.
  */
@@ -815,6 +815,7 @@ EC_POINT_new(const EC_GROUP *group)
                 goto err;
 
         point->meth = group->meth;
+        point->nid = group->nid;
 
         return point;
 
@@ -856,6 +857,8 @@ EC_POINT_copy(EC_POINT *dst, const EC_POINT *src)
         if (dst == src)
                 return 1;
 
+        dst->nid = src->nid;
+
         if (!bn_copy(dst->X, src->X))
                 return 0;
         if (!bn_copy(dst->Y, src->Y))
diff --git a/src/lib/libcrypto/ec/ec_local.h b/src/lib/libcrypto/ec/ec_local.h
index 48a7d929ea..933fd98f14 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 1.71 2025/11/26 10:19:57 tb Exp $ */
+/* $OpenBSD: ec_local.h,v 1.72 2025/12/26 18:41:05 tb Exp $ */
 /*
  * Originally written by Bodo Moeller for the OpenSSL project.
  */
@@ -170,6 +170,7 @@ struct ec_group_st {
 
 struct ec_point_st {
         const EC_METHOD *meth;
+        int nid;
 
         /*
          * Jacobian projective coordinates: (X, Y, Z) represents (X/Z^2, Y/Z^3)