nixpkgs/nixos/doc/manual/configuration/luks-file-systems.xml
2020-01-22 08:38:16 +01:00

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<section xmlns="http://docbook.org/ns/docbook"
xmlns:xlink="http://www.w3.org/1999/xlink"
xmlns:xi="http://www.w3.org/2001/XInclude"
version="5.0"
xml:id="sec-luks-file-systems">
<title>LUKS-Encrypted File Systems</title>
<para>
NixOS supports file systems that are encrypted using
<emphasis>LUKS</emphasis> (Linux Unified Key Setup). For example, here is how
you create an encrypted Ext4 file system on the device
<filename>/dev/disk/by-uuid/3f6b0024-3a44-4fde-a43a-767b872abe5d</filename>:
<screen>
# cryptsetup luksFormat /dev/disk/by-uuid/3f6b0024-3a44-4fde-a43a-767b872abe5d
WARNING!
========
This will overwrite data on /dev/disk/by-uuid/3f6b0024-3a44-4fde-a43a-767b872abe5d irrevocably.
Are you sure? (Type uppercase yes): YES
Enter LUKS passphrase: ***
Verify passphrase: ***
# cryptsetup luksOpen /dev/disk/by-uuid/3f6b0024-3a44-4fde-a43a-767b872abe5d crypted
Enter passphrase for /dev/disk/by-uuid/3f6b0024-3a44-4fde-a43a-767b872abe5d: ***
# mkfs.ext4 /dev/mapper/crypted
</screen>
To ensure that this file system is automatically mounted at boot time as
<filename>/</filename>, add the following to
<filename>configuration.nix</filename>:
<programlisting>
<link linkend="opt-boot.initrd.luks.devices._name__.device">boot.initrd.luks.devices.crypted.device</link> = "/dev/disk/by-uuid/3f6b0024-3a44-4fde-a43a-767b872abe5d";
<xref linkend="opt-fileSystems"/>."/".device = "/dev/mapper/crypted";
</programlisting>
Should grub be used as bootloader, and <filename>/boot</filename> is located
on an encrypted partition, it is necessary to add the following grub option:
<programlisting><xref linkend="opt-boot.loader.grub.enableCryptodisk"/> = true;</programlisting>
</para>
<section xml:id="sec-luks-file-systems-fido2">
<title>FIDO2</title>
<para>
NixOS also supports unlocking your LUKS-Encrypted file system using a FIDO2 compatible token. In the following example, we will create a new FIDO2 credential
and add it as a new key to our existing device <filename>/dev/sda2</filename>:
<screen>
# export FIDO2_LABEL="/dev/sda2 @ $HOSTNAME"
# fido2luks credential "$FIDO2_LABEL"
f1d00200108b9d6e849a8b388da457688e3dd653b4e53770012d8f28e5d3b269865038c346802f36f3da7278b13ad6a3bb6a1452e24ebeeaa24ba40eef559b1b287d2a2f80b7
# fido2luks -i add-key /dev/sda2 f1d00200108b9d6e849a8b388da457688e3dd653b4e53770012d8f28e5d3b269865038c346802f36f3da7278b13ad6a3bb6a1452e24ebeeaa24ba40eef559b1b287d2a2f80b7
Password:
Password (again):
Old password:
Old password (again):
Added to key to device /dev/sda2, slot: 2
</screen>
To ensure that this file system is decrypted using the FIDO2 compatible key, add the following to <filename>configuration.nix</filename>:
<programlisting>
<link linkend="opt-boot.initrd.luks.fido2Support">boot.initrd.luks.fido2Support</link> = true;
<link linkend="opt-boot.initrd.luks.devices._name__.fido2.credential">boot.initrd.luks.devices."/dev/sda2".fido2.credential</link> = "f1d00200108b9d6e849a8b388da457688e3dd653b4e53770012d8f28e5d3b269865038c346802f36f3da7278b13ad6a3bb6a1452e24ebeeaa24ba40eef559b1b287d2a2f80b7";
</programlisting>
You can also use the FIDO2 passwordless setup, but for security reasons, you might want to enable it only when your device is PIN protected, such as <link xlink:href="https://trezor.io/">Trezor</link>.
<programlisting>
<link linkend="opt-boot.initrd.luks.devices._name__.fido2.passwordLess">boot.initrd.luks.devices."/dev/sda2".fido2.passwordLess</link> = true;
</programlisting>
</para>
</section>
</section>