hardened malloc, working firewall.

scripts/build_image.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 if [ "$(id -u)" -ne 0 ]; then
 	echo "switching from $(id -un) to root"
-	exec sudo "$0" "$@"
+	exec sudo ionice -c 3 "$0" "$@"
 fi
 set -e
 cd "$(dirname "$0")"