disko/lib/types/luks.nix

{
  config,
  options,
  lib,
  diskoLib,
  parent,
  device,
  ...
}:
let
  keyFile =
    if config.settings ? "keyFile" then
      config.settings.keyFile
    else if config.askPassword then
      ''<(set +x; echo -n "$password"; set -x)''
    else if
      config.passwordFile != null
    # do not print the password to the console
    then
      ''<(set +x; echo -n "$(cat ${config.passwordFile})"; set -x)''
    else if config.keyFile != null then
      lib.warn (
        "The option `keyFile` is deprecated."
        + "Use passwordFile instead if you want to use interactive login or settings.keyFile if you want to use key file login"
      ) config.keyFile
    else
      null;
  keyFileArgs = ''
    ${lib.optionalString (keyFile != null) "--key-file ${keyFile}"} \
    ${lib.optionalString (lib.hasAttr "keyFileSize" config.settings) "--keyfile-size ${builtins.toString config.settings.keyFileSize}"} \
    ${lib.optionalString (lib.hasAttr "keyFileOffset" config.settings) "--keyfile-offset ${builtins.toString config.settings.keyFileOffset}"} \
  '';
  cryptsetupOpen = ''
    cryptsetup open "${config.device}" "${config.name}" \
      ${lib.optionalString (config.settings.allowDiscards or false) "--allow-discards"} \
      ${
        lib.optionalString (config.settings.bypassWorkqueues or false
        ) "--perf-no_read_workqueue --perf-no_write_workqueue"
      } \
      ${toString config.extraOpenArgs} \
      ${keyFileArgs} \
  '';
in
{
  options = {
    type = lib.mkOption {
      type = lib.types.enum [ "luks" ];
      internal = true;
      description = "Type";
    };
    device = lib.mkOption {
      type = lib.types.str;
      description = "Device to encrypt";
      default = device;
    };
    name = lib.mkOption {
      type = lib.types.str;
      description = "Name of the LUKS";
    };
    keyFile = lib.mkOption {
      type = lib.types.nullOr diskoLib.optionTypes.absolute-pathname;
      default = null;
      description = "DEPRECATED use passwordFile or settings.keyFile. Path to the key for encryption";
      example = "/tmp/disk.key";
    };
    passwordFile = lib.mkOption {
      type = lib.types.nullOr diskoLib.optionTypes.absolute-pathname;
      default = null;
      description = "Path to the file which contains the password for initial encryption";
      example = "/tmp/disk.key";
    };
    askPassword = lib.mkOption {
      type = lib.types.bool;
      default = config.keyFile == null && config.passwordFile == null && (!config.settings ? "keyFile");
      defaultText = "true if neither keyFile nor passwordFile are set";
      description = "Whether to ask for a password for initial encryption";
    };
    settings = lib.mkOption {
      type = lib.types.attrsOf lib.types.anything;
      default = { };
      description = "LUKS settings (as defined in configuration.nix in boot.initrd.luks.devices.<name>)";
      example = ''
        {
                  keyFile = "/tmp/disk.key";
                  keyFileSize = 2048;
                  keyFileOffset = 1024;
                  fallbackToPassword = true;
                  allowDiscards = true;
                };
      '';
    };
    additionalKeyFiles = lib.mkOption {
      type = lib.types.listOf diskoLib.optionTypes.absolute-pathname;
      default = [ ];
      description = "Path to additional key files for encryption";
      example = [ "/tmp/disk2.key" ];
    };
    initrdUnlock = lib.mkOption {
      type = lib.types.bool;
      default = true;
      description = "Whether to add a boot.initrd.luks.devices entry for the specified disk.";
    };
    extraFormatArgs = lib.mkOption {
      type = lib.types.listOf lib.types.str;
      default = [ ];
      description = "Extra arguments to pass to `cryptsetup luksFormat` when formatting";
      example = [ "--pbkdf argon2id" ];
    };
    extraOpenArgs = lib.mkOption {
      type = lib.types.listOf lib.types.str;
      default = [ ];
      description = "Extra arguments to pass to `cryptsetup luksOpen` when opening";
      example = [ "--timeout 10" ];
    };
    content = diskoLib.deviceType {
      parent = config;
      device = "/dev/mapper/${config.name}";
    };
    _parent = lib.mkOption {
      internal = true;
      default = parent;
    };
    _meta = lib.mkOption {
      internal = true;
      readOnly = true;
      type = lib.types.functionTo diskoLib.jsonType;
      default = dev: lib.optionalAttrs (config.content != null) (config.content._meta dev);
      description = "Metadata";
    };
    _create = diskoLib.mkCreateOption {
      inherit config options;
      default = ''
        if ! blkid "${config.device}" >/dev/null || ! cryptsetup isLuks "${config.device}"; then
          ${lib.optionalString config.askPassword ''
            promptSecret() {
              prompt=$1
              var=$2

              echo -n "$prompt"
              IFS= read -r -s "$var"
              echo
            }

            askPassword() {
              if [ -z ''${IN_DISKO_TEST+x} ]; then
                set +x
                promptSecret "Enter password for ${config.device}: " password
                promptSecret "Enter password for ${config.device} again to be safe: " password_check
                export password
                if [ "$password" != "$password_check" ]; then
                  exit 1
                fi
                set -x
              else
                export password=disko
              fi
            }
            until askPassword; do
              echo "Passwords did not match, please try again."
            done
          ''}
          cryptsetup -q luksFormat "${config.device}" ${toString config.extraFormatArgs} ${keyFileArgs}
        fi

        if ! cryptsetup status "${config.name}" >/dev/null; then
          ${cryptsetupOpen} --persistent
        fi
        ${toString (
          lib.forEach config.additionalKeyFiles (keyFile: ''
            cryptsetup luksAddKey "${config.device}" ${keyFile} ${keyFileArgs}
          '')
        )}

        ${lib.optionalString (config.content != null) config.content._create}
      '';
    };
    _mount = diskoLib.mkMountOption {
      inherit config options;
      default =
        let
          contentMount = config.content._mount;
        in
        {
          dev = ''
            if ! cryptsetup status "${config.name}" >/dev/null 2>/dev/null; then
              ${lib.optionalString config.askPassword ''
                if [ -z ''${IN_DISKO_TEST+x} ]; then
                  set +x
                  echo "Enter password for ${config.device}"
                  IFS= read -r -s password
                  export password
                  set -x
                else
                  export password=disko
                fi
              ''}
              ${cryptsetupOpen}
            fi
            ${lib.optionalString (config.content != null) contentMount.dev or ""}
          '';
          fs = lib.optionalAttrs (config.content != null) contentMount.fs or { };
        };
    };
    _unmount = diskoLib.mkUnmountOption {
      inherit config options;
      default =
        let
          contentUnmount = config.content._unmount;
        in
        {
          dev = ''
            ${lib.optionalString (config.content != null) contentUnmount.dev or ""}
            if cryptsetup status "${config.name}" >/dev/null 2>/dev/null; then
              cryptsetup close "${config.name}"
            fi
          '';
          fs = lib.optionalAttrs (config.content != null) contentUnmount.fs or { };
        };
    };
    _config = lib.mkOption {
      internal = true;
      readOnly = true;
      default =
        [ ]
        # If initrdUnlock is true, then add a device entry to the initrd.luks.devices config.
        ++ (lib.optional config.initrdUnlock [
          {
            boot.initrd.luks.devices.${config.name} = {
              inherit (config) device;
            }
            // config.settings;
          }
        ])
        ++ (lib.optional (config.content != null) config.content._config);
      description = "NixOS configuration";
    };
    _pkgs = lib.mkOption {
      internal = true;
      readOnly = true;
      type = lib.types.functionTo (lib.types.listOf lib.types.package);
      default =
        pkgs:
        [
          pkgs.gnugrep
          pkgs.cryptsetup
        ]
        ++ (lib.optionals (config.content != null) (config.content._pkgs pkgs));
      description = "Packages";
    };
  };
}