Add compatibility check to EC_POINT_mul()

This is the only public API that doesn't check for compatibility between
group and point. Add the missing check.

ok jsing kenjiro

1 files changed, 7 insertions, 1 deletions

diff --git a/src/lib/libcrypto/ec/ec_lib.c b/src/lib/libcrypto/ec/ec_lib.c
index c140249f0e..dc8800dff2 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 1.129 2025/12/26 18:44:19 tb Exp $ */
+/* $OpenBSD: ec_lib.c,v 1.130 2025/12/26 18:45:42 tb Exp $ */
 /*
  * Originally written by Bodo Moeller for the OpenSSL project.
  */
@@ -1343,6 +1343,12 @@ EC_POINT_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *g_scalar,
                 goto err;
         }
 
+        if (!ec_group_and_point_compatible(group, r) ||
+            (point != NULL && !ec_group_and_point_compatible(group, point))) {
+                ECerror(EC_R_INCOMPATIBLE_OBJECTS);
+                goto err;
+        }
+
         if (g_scalar != NULL && point == NULL && p_scalar == NULL) {
                 /*
                  * In this case we want to compute g_scalar * GeneratorPoint: