Improve dynamic call array by checking at load-time

Author: fwsGonzo

engine/src/script/script.cpp

@@ -395,19 +395,6 @@ void Script::dynamic_call_hash(uint32_t hash, gaddr_t straddr)
 	}
 }
 
-void Script::dynamic_call_array(uint32_t idx)
-{
-	while (true) {
-		try {
-			this->m_dyncall_array.at(idx)(*this);
-			return;
-		} catch (const std::exception& e) {
-			// This will re-throw unless a new dynamic call is discovered
-			this->dynamic_call_error(idx, e);
-		}
-	}
-}
-
 void Script::dynamic_call_error(uint32_t idx, const std::exception& e)
 {
 	const uint32_t entries = machine().memory.read<uint32_t> (m_g_dyncall_table);

engine/src/script/script.hpp

@@ -120,7 +120,7 @@ struct Script
 	static void
 		set_dynamic_calls(std::vector<std::tuple<std::string, std::string, ghandler_t>>);
 	void dynamic_call_hash(uint32_t hash, gaddr_t strname);
-	void dynamic_call_array(uint32_t idx);
+	void dynamic_call_array_unchecked(uint32_t idx);
 
 	/// @brief Retrieve arguments passed to a dynamic call, specifying each type.
 	/// @tparam ...Args The types of arguments to retrieve.
@@ -556,3 +556,16 @@ template <typename T> inline GuestObjects<T> Script::guest_alloc(size_t n)
 	}
 	throw std::runtime_error("Unable to allocate guest objects");
 }
+
+inline void Script::dynamic_call_array_unchecked(uint32_t idx)
+{
+	while (true) {
+		try {
+			this->m_dyncall_array[idx](*this);
+			return;
+		} catch (const std::exception& e) {
+			// This will re-throw unless a new dynamic call is discovered
+			this->dynamic_call_error(idx, e);
+		}
+	}
+}

engine/src/script/script_syscalls.cpp

@@ -191,7 +191,7 @@ void Script::setup_syscall_interface()
 		[](CPU<MARCH>& cpu, rv32i_instruction instr)
 		{
 			auto& scr = script(cpu.machine());
-			scr.dynamic_call_array(instr.Itype.imm);
+			scr.dynamic_call_array_unchecked(instr.Itype.imm);
 		},
 		[](char* buffer, size_t len, auto&, rv32i_instruction instr)
 		{
@@ -250,7 +250,9 @@ void Script::setup_syscall_interface()
 	{
 		if (instr.opcode() == 0b1011011)
 		{
-			return dyncall_instruction_handler;
+			if (instr.Itype.imm < ECALL_LAST - GAME_API_BASE)
+				return dyncall_instruction_handler;
+			throw std::runtime_error("Invalid dynamic call found in program");
 		}
 		if (instr.opcode() == 0b0001011)
 		{