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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/4.5/docbookx.dtd">
<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
<refentry id="pam_systemd_loadkey" conditional='HAVE_PAM' xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>pam_systemd_loadkey</title>
<productname>systemd</productname>
</refentryinfo>
<refmeta>
<refentrytitle>pam_systemd_loadkey</refentrytitle>
<manvolnum>8</manvolnum>
</refmeta>
<refnamediv>
<refname>pam_systemd_loadkey</refname>
<refpurpose>Read password from kernel keyring and set it as PAM authtok</refpurpose>
</refnamediv>
<refsynopsisdiv>
<para><filename>pam_systemd_loadkey.so</filename></para>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><command>pam_systemd_loadkey</command> reads a NUL-separated password list from the kernel keyring,
and sets the last password in the list as the PAM authtok, which can be used by e.g.
<citerefentry project='man-pages'><refentrytitle>pam_get_authtok</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
</para>
<para>The password list is supposed to be stored in the "user" keyring of the root user,
by an earlier call to
<citerefentry><refentrytitle>systemd-ask-password</refentrytitle><manvolnum>1</manvolnum></citerefentry>
with <option>--keyname=</option>.
You can pass the keyname to <command>pam_systemd_loadkey</command> via the <option>keyname=</option> option.</para>
</refsect1>
<refsect1>
<title>Options</title>
<para>The following options are understood:</para>
<variablelist class='pam-directives'>
<varlistentry>
<term><varname>keyname=</varname></term>
<listitem><para>Takes a string argument which sets the keyname to read.
The default is <literal>cryptsetup</literal>.
During boot,
<citerefentry><refentrytitle>systemd-cryptsetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
stores a passphrase or PIN in the keyring.
The LUKS2 volume key can also be used, via the <option>link-volume-key</option> option in
<citerefentry><refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
<table>
<title>
Possible values for <varname>keyname</varname>.
</title>
<tgroup cols='2'>
<colspec colname='value' />
<colspec colname='description' />
<thead>
<row>
<entry>Value</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>cryptsetup</entry>
<entry>Passphrase or recovery key</entry>
</row>
<row>
<entry>fido2-pin</entry>
<entry>Security token PIN</entry>
</row>
<row>
<entry>luks2-pin</entry>
<entry>LUKS2 token PIN</entry>
</row>
<row>
<entry>tpm2-pin</entry>
<entry>TPM2 PIN</entry>
</row>
</tbody>
</tgroup>
</table>
<xi:include href="version-info.xml" xpointer="v255"/></listitem>
</varlistentry>
<varlistentry>
<term><varname>debug</varname></term>
<listitem><para>The module will log debugging information as it operates.</para>
<xi:include href="version-info.xml" xpointer="v255"/></listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Example</title>
<para>This module is intended to be used when you use LUKS with a passphrase, enable autologin in the display
manager, and want to unlock Gnome Keyring / KDE KWallet automatically. So in total, you only enter one password
during boot.</para>
<para>You need to set the password of your Gnome Keyring/KWallet to the same as your LUKS passphrase.
Then add the following lines to your display manager's PAM config under <filename>/etc/pam.d/</filename> (e.g.
<filename>sddm-autologin</filename>):</para>
<programlisting>
-auth optional pam_systemd_loadkey.so
-auth optional pam_gnome_keyring.so
-session optional pam_gnome_keyring.so auto_start
-session optional pam_kwallet5.so auto_start
</programlisting>
<para>And add the following lines to your display manager's systemd service file, so it can access root's keyring:</para>
<programlisting>
[Service]
KeyringMode=inherit
</programlisting>
<para>In this setup, early during the boot process,
<citerefentry><refentrytitle>systemd-cryptsetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
will ask for the passphrase and store it in the kernel keyring with the keyname <literal>cryptsetup</literal>.
Then when the display manager does the autologin, <command>pam_systemd_loadkey</command> will read the passphrase
from the kernel keyring, set it as the PAM authtok, and then <command>pam_gnome_keyring</command> and
<command>pam_kwallet5</command> will unlock with the same passphrase.</para>
</refsect1>
</refentry>
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