From 22d7e6331d8fb1be0989218807c693fad696090a Mon Sep 17 00:00:00 2001
From: James R <justsomejames2@gmail.com>
Date: Sun, 11 Feb 2024 05:33:20 -0800
Subject: [PATCH] Got_Luacmd: ensure lua stack is large enough for command
 arguments

---
 src/lua_consolelib.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/lua_consolelib.c b/src/lua_consolelib.c
index 87c0f98bc..ec39cab33 100644
--- a/src/lua_consolelib.c
+++ b/src/lua_consolelib.c
@@ -29,6 +29,12 @@ return luaL_error(L, "HUD rendering code should not call this function!");
 
 static consvar_t *this_cvar;
 
+static void clear_lua_stack(void)
+{
+	if (gL) // check if Lua is actually turned on first, you dummmy -- Monster Iestyn 04/07/18
+		lua_settop(gL, 0); // clear stack
+}
+
 void Got_Luacmd(UINT8 **cp, INT32 playernum)
 {
 	UINT8 i, argc, flags;
@@ -87,6 +93,13 @@ void Got_Luacmd(UINT8 **cp, INT32 playernum)
 
 	lua_remove(gL, -2); // pop command info table
 
+	if (!lua_checkstack(gL, argc)) // player + command arguments
+	{
+		clear_lua_stack();
+		CONS_Alert(CONS_WARNING, "lua command stack overflow from %s (%d, need %d more)\n", player_names[playernum], lua_gettop(gL), argc);
+		return;
+	}
+
 	LUA_PushUserdata(gL, &players[playernum], META_PLAYER);
 	for (i = 1; i < argc; i++)
 	{
@@ -101,8 +114,7 @@ void Got_Luacmd(UINT8 **cp, INT32 playernum)
 
 deny:
 	//must be hacked/buggy client
-	if (gL) // check if Lua is actually turned on first, you dummmy -- Monster Iestyn 04/07/18
-		lua_settop(gL, 0); // clear stack
+	clear_lua_stack();
 
 	CONS_Alert(CONS_WARNING, M_GetText("Illegal lua command received from %s\n"), player_names[playernum]);
 	if (server)