linux: Request no new privileges: https://docs.kernel.org/userspace-api/no_new_privs.html.

src/main.c

@@ -2055,6 +2055,13 @@ void tf_run_thread_start(const char* zip_path)
 #else
 int main(int argc, char* argv[])
 {
+#if defined(__linux__)
+	if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) != 0)
+	{
+		tf_printf("Unable to set no new privileges flag: %s\n", strerror(errno));
+		return EXIT_FAILURE;
+	}
+#endif
 	setvbuf(stdout, NULL, _IONBF, 0);
 	_startup(argc, argv);
 	ares_library_init(0);