diff --git a/net/netfilter/xt_helper.c b/net/netfilter/xt_helper.c
index 9f4ab00c8050..805c9f64a04c 100644
--- a/net/netfilter/xt_helper.c
+++ b/net/netfilter/xt_helper.c
@@ -65,7 +65,7 @@ static int helper_mt_check(const struct xt_mtchk_param *par)
 			par->family);
 		return ret;
 	}
-	info->name[29] = '\0';
+	info->name[sizeof(info->name) - 1] = '\0';
 	return 0;
 }