1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
|
<?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.</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, pam_systemd_loadkey will read the passphrase from the kernel keyring,
set it as the PAM authtok, and then pam_gnome_keyring and pam_kwallet5 will unlock with the same passphrase.</para>
</refsect1>
</refentry>
|
