Lua CAN bus index: let's fail if invalid value specified

firmware/controllers/lua/can_filter.cpp

@@ -1,5 +1,6 @@
 #include "pch.h"
 #include "can_filter.h"
+#include "can_hw.h"
 
 static constexpr size_t maxFilterCount = 48;
 
@@ -26,6 +27,10 @@ void resetLuaCanRx() {
 }
 
 void addLuaCanRxFilter(int32_t eid, uint32_t mask, int bus, int callback) {
+    if (bus != ANY_BUS) {
+        assertHwCanBusIndex(bus);
+    }
+
 	if (filterCount >= maxFilterCount) {
 		firmwareError(OBD_PCM_Processor_Fault, "Too many Lua CAN RX filters");
 	}

firmware/hw_layer/drivers/can/can_hw.cpp

@@ -334,3 +334,10 @@ bool getIsCanEnabled(void) {
 }
 
 #endif /* EFI_CAN_SUPPORT */
+
+void assertHwCanBusIndex(const size_t busIndex) {
+    // 'size_t' is an unsigned type so we are never below zero here
+	if (busIndex > 1) {
+  		firmwareError(CUSTOM_OBD_70, "Invalid HW CAN bus index %d", busIndex);
+  	}
+}

firmware/hw_layer/drivers/can/can_hw.h

@@ -19,7 +19,11 @@ void stopCanPins();
 void startCanPins();
 void enableFrankensoCan();
 bool getIsCanEnabled(void);
+
 #if EFI_TUNER_STUDIO
 void postCanState();
 #endif /* EFI_TUNER_STUDIO */
+
 #endif /* EFI_CAN_SUPPORT */
+
+void assertHwCanBusIndex(const size_t busIndex);

unit_tests/Makefile

@@ -34,6 +34,7 @@ CPPSRC += $(ALLCPPSRC) \
 	$(DEVELOPMENT_DIR)/engine_sniffer.cpp \
 	$(CONSOLE_COMMON_SRC_CPP) \
 	$(PROJECT_DIR)/config/boards/hellen/hellen_board_id.cpp \
+	$(PROJECT_DIR)/hw_layer/drivers/can/can_hw.cpp \
 	$(PROJECT_DIR)/../unit_tests/logicdata.cpp \
 	$(PROJECT_DIR)/../unit_tests/native/native_impl.cpp \
 	$(PROJECT_DIR)/../unit_tests/main.cpp \