nixpkgs-suyu/modules/system/boot/luksroot.nix
Evgeny Egorochkin 0f11519d45 LuksRoot: add more modules to load by default and let users add more or override the list. Added every module
mentioned by most popular guides, benchmarks and discussions to make things just work.
2013-01-13 12:44:16 +02:00

172 lines
5.7 KiB
Nix

{pkgs, config, ...}:
with pkgs.lib;
let
luks = config.boot.initrd.luks;
openCommand = { name, device, keyFile, keyFileSize, 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
${optionalString (keyFile != null) ''
if ! test -e ${keyFile}; then
echo -n "waiting 10 seconds for key file ${keyFile} to appear..."
for try in $(seq 10); do
sleep 1
if test -e ${keyFile}; then break; fi
echo -n .
done
echo "ok"
fi
''}
# open luksRoot and scan for logical volumes
cryptsetup luksOpen ${device} ${name} ${optionalString allowDiscards "--allow-discards"} \
${optionalString (keyFile != null) "--key-file=${keyFile} ${optionalString (keyFileSize != null) "--keyfile-size=${toString keyFileSize}"}"}
'';
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.mitigateDMAAttacks = mkOption {
default = true;
description = ''
Unless enabled, encryption keys can be easily recovered by an attacker with physical
access to any machine with PCMCIA, ExpressCard, ThunderBolt or FireWire port.
More information: http://en.wikipedia.org/wiki/DMA_attack
This option blacklists FireWire drivers, but doesn't remove them. You can manually
load the drivers if you need to use a FireWire device, but don't forget to unload them!
'';
};
boot.initrd.luks.cryptoModules = mkOption {
default = [ "aes_generic" "aes_x86_64" "blowfish" "twofish" "serpent" "cbc" "xts" "lrw" "sha256" "sha1" "sha2" ];
description = ''
A list of cryptographic kernel modules needed to decrypt the root device(s).
The default includes all common modules.
'';
};
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.";
};
keyFile = mkOption {
default = null;
example = "/dev/sdb1";
type = types.nullOr types.string;
description = ''
The name of the file (can be a raw device or a partition) that
should be used as the decryption key for the encrypted device. If
not specified, you will be prompted for a passphrase instead.
'';
};
keyFileSize = mkOption {
default = null;
example = 4096;
type = types.nullOr types.int;
description = ''
The size of the key file. Use this if only the beginning of the
key file should be used as a key (often the case if a raw device
or partition is used as key file). If not specified, the whole
<literal>keyFile</literal> will be used decryption, instead of just
the first <literal>keyFileSize</literal> bytes.
'';
};
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 != []) {
# actually, sbp2 driver is the one enabling the DMA attack, but this needs to be tested
boot.blacklistedKernelModules = optionals luks.mitigateDMAAttacks
["firewire_ohci" "firewire_core" "firewire_sbp2"];
# Some modules that may be needed for mounting anything ciphered
boot.initrd.kernelModules = [ "dm_mod" "dm_crypt" "cryptd" ] ++ luks.cryptoModules;
# 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 ];
};
}