nixpkgs/modules/system/boot/luksroot.nix

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{pkgs, config, ...}:
with pkgs.lib;
let
luks = config.boot.initrd.luks;
openCommand = { name, device, allowDiscards, ... }: ''
# Wait for luksRoot to appear, e.g. if on a usb drive.
# XXX: copied and adapted from stage-1-init.sh - should be
# available as a function.
if ! test -e ${device}; then
echo -n "waiting 10 seconds for device ${device} to appear..."
for try in $(seq 10); do
sleep 1
if test -e ${device}; then break; fi
echo -n .
done
echo "ok"
fi
# open luksRoot and scan for logical volumes
cryptsetup luksOpen ${device} ${name} ${optionalString allowDiscards "--allow-discards"}
'';
isPreLVM = f: f.preLVM;
preLVM = filter isPreLVM luks.devices;
postLVM = filter (f: !(isPreLVM f)) luks.devices;
in
{
options = {
boot.initrd.luks.enable = mkOption {
default = false;
description = "Obsolete.";
};
boot.initrd.luks.devices = mkOption {
default = [ ];
example = [ { name = "luksroot"; device = "/dev/sda3"; preLVM = true; } ];
description = ''
The list of devices that should be decrypted using LUKS before trying to mount the
root partition. This works for both LVM-over-LUKS and LUKS-over-LVM setups.
The devices are decrypted to the device mapper names defined.
Make sure that initrd has the crypto modules needed for decryption.
'';
type = types.list types.optionSet;
options = {
name = mkOption {
example = "luksroot";
type = types.string;
description = "Named to be used for the generated device in /dev/mapper.";
};
device = mkOption {
example = "/dev/sda2";
type = types.string;
description = "Path of the underlying block device.";
};
preLVM = mkOption {
default = true;
type = types.bool;
description = "Whether the luksOpen will be attempted before LVM scan or after it.";
};
allowDiscards = mkOption {
default = false;
type = types.bool;
description = ''
Whether to allow TRIM requests to the underlying device. This option
has security implications, please read the LUKS documentation before
activating in.
'';
};
};
};
};
config = mkIf (luks.devices != []) {
# Some modules that may be needed for mounting anything ciphered
boot.initrd.kernelModules = [ "aes_generic" "aes_x86_64" "dm_mod" "dm_crypt"
"sha256_generic" "cbc" "cryptd" ];
# copy the cryptsetup binary and it's dependencies
boot.initrd.extraUtilsCommands = ''
cp -pdv ${pkgs.cryptsetup}/sbin/cryptsetup $out/bin
# XXX: do we have a function that does this?
for lib in $(ldd $out/bin/cryptsetup |grep '=>' |grep /nix/store/ |cut -d' ' -f3); do
cp -pdvn $lib $out/lib
cp -pvn $(readlink -f $lib) $out/lib
done
'';
boot.initrd.extraUtilsCommandsTest = ''
$out/bin/cryptsetup --version
'';
boot.initrd.preLVMCommands = concatMapStrings openCommand preLVM;
boot.initrd.postDeviceCommands = concatMapStrings openCommand postLVM;
environment.systemPackages = [ pkgs.cryptsetup ];
};
}