Installation of NixOS with encrypted root

tipi.md

Installation of NixOS with encrypted root

These are my notes on instaling NixOS 16.03 on a Lenovo ThinkPad X1 Carbon (4th generation) with an encrypted root file system using UEFI.

Most of this is scrambled from the following pages:

• Encrypted Root on NixOS - Nix Wiki
• Installing NixOS - Chris Martin
• Linux administration and use - Earl Douglas
• Installing NixOS on a ThinkPad W540 with encrypted root - Bluish Coder

Preparing installation media

I installed from a USB stick using the NixOS minimal ISO (this one to be precise).

$ dd bs=4M if=nixos-minimal-16.03.678.2597f52-x86_64-linux.iso of=/dev/sdb

Booting the installer

• Disable Secure Boot Control
• Disable USB legacy boot
• Enable Launch CSM

Due to this kernel bug, we have to boot with the following kernel parameter: intel_pstate=no_hwp. Seems like this will be fixed soon.

Partitioning

We create a 500MB EFI boot partition (/dev/sda1) and the rest will be our LUKS encrypted physical volume for LVM (/dev/sda2).

$ gdisk /dev/sda

• o (create new empty partition table)
• n (add partition, 500M, type ef00 EFI)
• n (add partition, remaining space, type 8300 Linux LVM)
• w (write partition table and exit)

Setup the encrypted LUKS partition and open it:

$ cryptsetup luksFormat /dev/sda2
$ cryptsetup luksOpen /dev/sda2 enc-pv

We create two logical volumes, a 8GB swap parition and the rest will be our root filesystem

$ pvcreate /dev/mapper/enc-pv
$ vgcreate vg /dev/mapper/enc-pv
$ lvcreate -L 8G -n swap vg
$ lvcreate -l '100%FREE' -n root vg

Format the partitions:

$ mkfs.fat /dev/sda1
$ mkfs.ext4 -L root /dev/vg/root
$ mkswap -L swap /dev/vg/swap

Installing NixOS

We mount the partitions we just created under /mnt so we can install NixOS on them.

$ mount /dev/vg/root /mnt
$ mkdir /mnt/boot
$ mount /dev/sda1 /mnt/boot
$ swapon /dev/vg/swap

Configure WPA supplicant so we can use WIFI:

$ cat > /etc/wpa_supplicant.conf
network={
  ssid="****"
  psk="****"
}
^D
$ systemctl start wpa_supplicant

Now generate a NixOS configuration and modify it to suit our partitioning. The following is a condensed configuration of what I came up with.

$ nixos-generate-config --root /mnt
$ cat > /mnt/etc/nixos/configuration.nix
{ config, pkgs, ... }:

{
  imports =
    [ # Include the results of the hardware scan.
      ./hardware-configuration.nix
    ];

  # Use the GRUB 2 boot loader.
  boot.loader.grub.enable = true;
  boot.loader.grub.version = 2;
  # Define on which hard drive you want to install Grub.
  # boot.loader.grub.device = "/dev/sda";
  boot.loader.grub.device = "nodev";
  boot.loader.grub.efiSupport = true;

  boot.initrd.luks.devices = [
    {
      name = "root";
      device = "/dev/sda2";
      preLVM = true;
      allowDiscards = true;
    }
  ];

  # networking.hostName = "nixos"; # Define your hostname.
  networking.hostName = "tipi";
  # networking.wireless.enable = true;  # Enables wireless support via wpa_supplicant.
  networking.wireless.enable = true;

  # Select internationalisation properties.
  # i18n = {
  #   consoleFont = "Lat2-Terminus16";
  #   consoleKeyMap = "us";
  #   defaultLocale = "en_US.UTF-8";
  # };

  # Set your time zone.
  # time.timeZone = "Europe/Amsterdam";

  # List packages installed in system profile. To search by name, run:
  # $ nix-env -qaP | grep wget
  # environment.systemPackages = with pkgs; [
  #   wget
  # ];

  # List services that you want to enable:

  # Enable the OpenSSH daemon.
  # services.openssh.enable = true;

  # Enable CUPS to print documents.
  # services.printing.enable = true;

  # Enable the X11 windowing system.
  # services.xserver.enable = true;
  # services.xserver.layout = "us";
  # services.xserver.xkbOptions = "eurosign:e";

  # Enable the KDE Desktop Environment.
  # services.xserver.displayManager.kdm.enable = true;
  # services.xserver.desktopManager.kde4.enable = true;

  # Define a user account. Don't forget to set a password with ‘passwd’.
  # users.extraUsers.guest = {
  #   isNormalUser = true;
  #   uid = 1000;
  # };

  # The NixOS release to be compatible with for stateful data such as databases.
  system.stateVersion = "16.03";

}

If we reboot, we can get back to this state with:

cryptsetup luksOpen /dev/sda2 enc-pv
lvchange -a y /dev/vg/swap
lvchange -a y /dev/vg/root
mount /dev/vg/root /mnt
mount /dev/sda1 /mnt/boot
swapon /dev/vg/swap
cp /mnt/etc/wpa_supplicant.conf /etc
systemctl start wpa_supplicant

nixos-install
reboot