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<?xml version="1.0"?>
<!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
<refentry id="systemd-cryptsetup-generator" conditional='HAVE_LIBCRYPTSETUP'>
<refentryinfo>
<title>systemd-cryptsetup-generator</title>
<productname>systemd</productname>
</refentryinfo>
<refmeta>
<refentrytitle>systemd-cryptsetup-generator</refentrytitle>
<manvolnum>8</manvolnum>
</refmeta>
<refnamediv>
<refname>systemd-cryptsetup-generator</refname>
<refpurpose>Unit generator for <filename>/etc/crypttab</filename></refpurpose>
</refnamediv>
<refsynopsisdiv>
<para><filename>/usr/lib/systemd/system-generators/systemd-cryptsetup-generator</filename></para>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><filename>systemd-cryptsetup-generator</filename> is a
generator that translates <filename>/etc/crypttab</filename> into
native systemd units early at boot and when configuration of the
system manager is reloaded. This will create
<citerefentry><refentrytitle>systemd-cryptsetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
units as necessary.</para>
<para><filename>systemd-cryptsetup-generator</filename> implements
<citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
</refsect1>
<refsect1>
<title>Kernel Command Line</title>
<para><filename>systemd-cryptsetup-generator</filename>
understands the following kernel command line parameters:</para>
<variablelist class='kernel-commandline-options'>
<varlistentry>
<term><varname>luks=</varname></term>
<term><varname>rd.luks=</varname></term>
<listitem><para>Takes a boolean argument. Defaults to <literal>yes</literal>. If
<literal>no</literal>, disables the generator entirely. <varname>rd.luks=</varname> is honored only
in the initrd while <varname>luks=</varname> is honored by both the main system and in the initrd.
</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>luks.crypttab=</varname></term>
<term><varname>rd.luks.crypttab=</varname></term>
<listitem><para>Takes a boolean argument. Defaults to <literal>yes</literal>. If
<literal>no</literal>, causes the generator to ignore any devices configured in
<filename>/etc/crypttab</filename> (<varname>luks.uuid=</varname> will still work however).
<varname>rd.luks.crypttab=</varname> is honored only in initrd while
<varname>luks.crypttab=</varname> is honored by both the main system and the initrd.
</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>luks.uuid=</varname></term>
<term><varname>rd.luks.uuid=</varname></term>
<listitem><para>Takes a LUKS superblock UUID as argument. This will activate the specified device as
part of the boot process as if it was listed in <filename>/etc/crypttab</filename>. This option may
be specified more than once in order to set up multiple devices. <varname>rd.luks.uuid=</varname> is
honored only in the initrd, while <varname>luks.uuid=</varname> is honored by both the main system
and the initrd.</para>
<para>If <filename>/etc/crypttab</filename> contains entries with the same UUID, then the name,
keyfile and options specified there will be used. Otherwise, the device will have the name
<literal>luks-UUID</literal>.</para>
<para>If <filename>/etc/crypttab</filename> exists, only those UUIDs specified on the kernel command
line will be activated in the initrd or the real root.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><varname>luks.name=</varname></term>
<term><varname>rd.luks.name=</varname></term>
<listitem><para>Takes a LUKS super block UUID followed by an
<literal>=</literal> and a name. This implies
<varname>rd.luks.uuid=</varname> or
<varname>luks.uuid=</varname> and will additionally make the
LUKS device given by the UUID appear under the provided
name.</para>
<para>This parameter is the analogue of the first <citerefentry><refentrytitle>crypttab</refentrytitle>
<manvolnum>5</manvolnum></citerefentry> field <replaceable>volume-name</replaceable>.</para>
<para><varname>rd.luks.name=</varname> is honored only in the initrd, while
<varname>luks.name=</varname> is honored by both the main system and the initrd.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><varname>luks.data=</varname></term>
<term><varname>rd.luks.data=</varname></term>
<listitem><para>Takes a LUKS super block UUID followed by a <literal>=</literal> and a block device
specification for device hosting encrypted data.</para>
<para>For those entries specified with <varname>rd.luks.uuid=</varname> or
<varname>luks.uuid=</varname>, the data device will be set to the one specified by
<varname>rd.luks.data=</varname> or <varname>luks.data=</varname> of the corresponding UUID.</para>
<para>LUKS data device parameter is useful for specifying encrypted data devices with detached headers specified in
<varname>luks.options</varname> entry containing <literal>header=</literal> argument. For example,
<varname>rd.luks.uuid=</varname>b40f1abf-2a53-400a-889a-2eccc27eaa40
<varname>rd.luks.options=</varname>b40f1abf-2a53-400a-889a-2eccc27eaa40=header=/path/to/luks.hdr
<varname>rd.luks.data=</varname>b40f1abf-2a53-400a-889a-2eccc27eaa40=/dev/sdx.
Hence, in this case, we will attempt to unlock LUKS device assembled from data device <literal>/dev/sdx</literal>
and LUKS header (metadata) put in <literal>/path/to/luks.hdr</literal> file. This syntax is for now
only supported on a per-device basis, i.e. you have to specify LUKS device UUID.</para>
<para>This parameter is the analogue of the second <citerefentry><refentrytitle>crypttab</refentrytitle>
<manvolnum>5</manvolnum></citerefentry> field <replaceable>encrypted-device</replaceable>.</para>
<para><varname>rd.luks.data=</varname> is honored only in the initrd, while
<varname>luks.data=</varname> is honored by both the main system and in the initrd.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><varname>luks.key=</varname></term>
<term><varname>rd.luks.key=</varname></term>
<listitem><para>Takes a password file name as argument or a
LUKS super block UUID followed by a <literal>=</literal> and a
password file name.</para>
<para>For those entries specified with
<varname>rd.luks.uuid=</varname> or
<varname>luks.uuid=</varname>, the password file will be set
to the one specified by <varname>rd.luks.key=</varname> or
<varname>luks.key=</varname> of the corresponding UUID, or the
password file that was specified without a UUID.</para>
<para>It is also possible to specify an external device which
should be mounted before we attempt to unlock the LUKS device.
systemd-cryptsetup will use password file stored on that
device. Device containing password file is specified by
appending colon and a device identifier to the password file
path. For example,
<varname>rd.luks.uuid=</varname>b40f1abf-2a53-400a-889a-2eccc27eaa40
<varname>rd.luks.key=</varname>b40f1abf-2a53-400a-889a-2eccc27eaa40=/keyfile:LABEL=keydev.
Hence, in this case, we will attempt to mount file system
residing on the block device with label <literal>keydev</literal>.
This syntax is for now only supported on a per-device basis,
i.e. you have to specify LUKS device UUID.</para>
<para>This parameter is the analogue of the third <citerefentry><refentrytitle>crypttab</refentrytitle>
<manvolnum>5</manvolnum></citerefentry> field <replaceable>key-file</replaceable>.</para>
<para><varname>rd.luks.key=</varname> is honored only in the initrd, while
<varname>luks.key=</varname> is honored by both the main system and in the initrd.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><varname>luks.options=</varname></term>
<term><varname>rd.luks.options=</varname></term>
<listitem><para>Takes a LUKS super block UUID followed by an
<literal>=</literal> and a string of options separated by
commas as argument. This will override the options for the
given UUID.</para>
<para>If only a list of options, without an UUID, is
specified, they apply to any UUIDs not specified elsewhere,
and without an entry in
<filename>/etc/crypttab</filename>.</para>
<para>This parameter is the analogue of the fourth <citerefentry><refentrytitle>crypttab</refentrytitle>
<manvolnum>5</manvolnum></citerefentry> field <replaceable>options</replaceable>.</para>
<para>It is possible to specify an external device which
should be mounted before we attempt to unlock the LUKS device.
systemd-cryptsetup will assemble LUKS device by combining
data device specified in <varname>luks.data</varname> with
detached LUKS header found in <literal>header=</literal>
argument. For example,
<varname>rd.luks.uuid=</varname>b40f1abf-2a53-400a-889a-2eccc27eaa40
<varname>rd.luks.options=</varname>b40f1abf-2a53-400a-889a-2eccc27eaa40=header=/luks.hdr:LABEL=hdrdev
<varname>rd.luks.data=</varname>b40f1abf-2a53-400a-889a-2eccc27eaa40=/dev/sdx.
Hence, in this case, we will attempt to mount file system
residing on the block device with label <literal>hdrdev</literal>, and look
for <literal>luks.hdr</literal> on that file system. Said header will be used
to unlock (decrypt) encrypted data stored on /dev/sdx.
This syntax is for now only supported on a per-device basis,
i.e. you have to specify LUKS device UUID.</para>
<para><varname>rd.luks.options=</varname> is honored only by initial
RAM disk (initrd) while <varname>luks.options=</varname> is
honored by both the main system and the initrd.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-cryptsetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-cryptenroll</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>
|
