Make tools (and thus elements) read-only in some contexts

Namely, in Select and Click tool callbacks, which are otherwise interface contexts and allow changing tools. This may cause use-after-free but it's much more likely to cause stack overflows. Importantly, the setter usage of ui.activeTool is considered to change tool state because it invokes Select callbacks.

src/gui/game/GameControllerEvents.h

@@ -12,6 +12,7 @@ enum EventTraits : uint32_t
 	eventTraitInterface         = UINT32_C(0x00000008),
 	eventTraitInterfaceGraphics = UINT32_C(0x00000010),
 	eventTraitConstSim          = UINT32_C(0x00000020),
+	eventTraitConstTools        = UINT32_C(0x00000040),
 };
 constexpr EventTraits operator |(EventTraits lhs, EventTraits rhs)
 {

src/lua/LuaElements.cpp

@@ -324,7 +324,7 @@ static bool luaCtypeDrawWrapper(CTYPEDRAW_FUNC_ARGS)
 static int allocate(lua_State *L)
 {
 	auto *lsi = GetLSI();
-	lsi->AssertInterfaceEvent();
+	lsi->AssertMutableToolsEvent();
 	luaL_checktype(L, 1, LUA_TSTRING);
 	luaL_checktype(L, 2, LUA_TSTRING);
 	auto group = tpt_lua_toByteString(L, 1).ToUpper();
@@ -422,7 +422,7 @@ static int element(lua_State *L)
 
 	if (lua_gettop(L) > 1)
 	{
-		lsi->AssertInterfaceEvent();
+		lsi->AssertMutableToolsEvent();
 		{
 			auto &sd = SimulationData::Ref();
 			std::unique_lock lk(sd.elementGraphicsMx);
@@ -573,7 +573,7 @@ static int property(lua_State *L)
 
 	if (lua_gettop(L) > 2)
 	{
-		lsi->AssertInterfaceEvent();
+		lsi->AssertMutableToolsEvent();
 		auto &sd = SimulationData::Ref();
 		std::unique_lock lk(sd.elementGraphicsMx);
 		auto &elements = sd.elements;
@@ -727,7 +727,7 @@ static int property(lua_State *L)
 static int ffree(lua_State *L)
 {
 	auto *lsi = GetLSI();
-	lsi->AssertInterfaceEvent();
+	lsi->AssertMutableToolsEvent();
 
 	int id = luaL_checkinteger(L, 1);
 	ByteString identifier;
@@ -773,7 +773,7 @@ static int exists(lua_State *L)
 static int loadDefault(lua_State *L)
 {
 	auto *lsi = GetLSI();
-	lsi->AssertInterfaceEvent();
+	lsi->AssertMutableToolsEvent();
 	auto &sd = SimulationData::Ref();
 	std::unique_lock lk(sd.elementGraphicsMx);
 	auto &elements = sd.elements;

src/lua/LuaInterface.cpp

@@ -256,6 +256,7 @@ static int activeTool(lua_State *L)
 		tpt_lua_pushByteString(L, lsi->gameModel->GetActiveTool(index)->Identifier);
 		return 1;
 	}
+	lsi->AssertMutableToolsEvent();
 	auto identifier = tpt_lua_checkByteString(L, 2);
 	auto *tool = lsi->gameModel->GetToolFromIdentifier(identifier);
 	if (!tool)

src/lua/LuaScriptInterface.cpp

@@ -900,6 +900,7 @@ void LuaScriptInterface::AssertInterfaceEvent()
 		luaL_error(L, "this functionality is restricted to interface events");
 	}
 }
+
 void LuaScriptInterface::AssertMutableSimEvent()
 {
 	if (eventTraits & eventTraitConstSim)
@@ -907,3 +908,12 @@ void LuaScriptInterface::AssertMutableSimEvent()
 		luaL_error(L, "this functionality is restricted to mutable simulation events");
 	}
 }
+
+void LuaScriptInterface::AssertMutableToolsEvent()
+{
+	AssertInterfaceEvent();
+	if (eventTraits & eventTraitConstTools)
+	{
+		luaL_error(L, "this functionality is restricted to mutable tool events");
+	}
+}

src/lua/LuaScriptInterface.h

@@ -153,6 +153,7 @@ public:
 
 	void AssertInterfaceEvent();
 	void AssertMutableSimEvent();
+	void AssertMutableToolsEvent();
 
 	friend class CommandInterface;
 };

src/lua/LuaTools.cpp

@@ -7,7 +7,7 @@
 static int allocate(lua_State *L)
 {
 	auto *lsi = GetLSI();
-	lsi->AssertInterfaceEvent();
+	lsi->AssertMutableToolsEvent();
 	luaL_checktype(L, 1, LUA_TSTRING);
 	luaL_checktype(L, 2, LUA_TSTRING);
 	auto group = tpt_lua_toByteString(L, 1).ToUpper();
@@ -51,7 +51,7 @@ static bool IsCustom(int index)
 static int ffree(lua_State *L)
 {
 	auto *lsi = GetLSI();
-	lsi->AssertInterfaceEvent();
+	lsi->AssertMutableToolsEvent();
 	int index = luaL_checkinteger(L, 1);
 	auto *tool = lsi->gameModel->GetToolByIndex(index);
 	if (!tool)
@@ -127,7 +127,7 @@ static void luaClickWrapper(SimTool *tool, Simulation *sim, const Brush &brush,
 		lua_pushboolean(L, tool->shiftBehaviour);
 		lua_pushboolean(L, tool->ctrlBehaviour);
 		lua_pushboolean(L, tool->altBehaviour);
-		if (tpt_lua_pcall(L, 7, 0, 0, eventTraitInterface))
+		if (tpt_lua_pcall(L, 7, 0, 0, eventTraitInterface | eventTraitConstTools))
 		{
 			lsi->Log(CommandInterface::LogError, "In click func: " + LuaGetError());
 			lua_pop(L, 1);
@@ -271,7 +271,7 @@ static void luaSelectWrapper(SimTool *tool, int toolSelection)
 	{
 		lua_rawgeti(L, LUA_REGISTRYINDEX, customTools[index].select);
 		lua_pushinteger(L, toolSelection);
-		if (tpt_lua_pcall(L, 1, 0, 0, eventTraitInterface))
+		if (tpt_lua_pcall(L, 1, 0, 0, eventTraitInterface | eventTraitConstTools))
 		{
 			lsi->Log(CommandInterface::LogError, "In select func: " + LuaGetError());
 			lua_pop(L, 1);
@@ -287,7 +287,7 @@ struct DependentFalse : std::false_type
 static int property(lua_State *L)
 {
 	auto *lsi = GetLSI();
-	lsi->AssertInterfaceEvent();
+	lsi->AssertMutableToolsEvent();
 	int index = luaL_checkinteger(L, 1);
 	auto *tool = lsi->gameModel->GetToolByIndex(index);
 	if (!tool)