From c851fc9bfbafb152a6a8ed91824475b15f7dd98f Mon Sep 17 00:00:00 2001
From: Alexander 'z33ky' Hirsch <1zeeky@gmail.com>
Date: Wed, 11 Jun 2025 02:11:09 +0200
Subject: [PATCH] Ensure the squirrel instance for native member function call
 actually has userpointer type

This prevents memory errors when incorrectly invoking native member
functions from Squirrel.
---
 sp/src/vscript/vscript_squirrel.cpp | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/sp/src/vscript/vscript_squirrel.cpp b/sp/src/vscript/vscript_squirrel.cpp
index 93008683..584402a1 100644
--- a/sp/src/vscript/vscript_squirrel.cpp
+++ b/sp/src/vscript/vscript_squirrel.cpp
@@ -1324,7 +1324,10 @@ SQInteger function_stub(HSQUIRRELVM vm)
 	SQInteger top = sq_gettop(vm);
 
 	SQUserPointer userptr = nullptr;
-	sq_getuserpointer(vm, top, &userptr);
+	if (SQ_FAILED(sq_getuserpointer(vm, top, &userptr)))
+	{
+		return sq_throwerror(vm, "Expected userpointer");
+	}
 
 	Assert(userptr);
 
@@ -1425,7 +1428,10 @@ SQInteger function_stub(HSQUIRRELVM vm)
 	if (pFunc->m_flags & SF_MEMBER_FUNC)
 	{
 		SQUserPointer self;
-		sq_getinstanceup(vm, 1, &self, nullptr);
+		if (SQ_FAILED(sq_getinstanceup(vm, 1, &self, 0)))
+		{
+			return sq_throwerror(vm, "Expected class userpointer");
+		}
 
 		if (!self)
 		{