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3<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
4  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
5<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
6<refentry id="systemd-veritysetup-generator" conditional='HAVE_LIBCRYPTSETUP'>
7
8  <refentryinfo>
9    <title>systemd-veritysetup-generator</title>
10    <productname>systemd</productname>
11  </refentryinfo>
12
13  <refmeta>
14    <refentrytitle>systemd-veritysetup-generator</refentrytitle>
15    <manvolnum>8</manvolnum>
16  </refmeta>
17
18  <refnamediv>
19    <refname>systemd-veritysetup-generator</refname>
20    <refpurpose>Unit generator for verity protected block devices</refpurpose>
21  </refnamediv>
22
23  <refsynopsisdiv>
24    <para><filename>/usr/lib/systemd/system-generators/systemd-veritysetup-generator</filename></para>
25  </refsynopsisdiv>
26
27  <refsect1>
28    <title>Description</title>
29
30    <para><filename>systemd-veritysetup-generator</filename> is a generator that translates kernel command line options
31    configuring verity protected block devices into native systemd units early at boot and when
32    configuration of the system manager is reloaded. This will create
33    <citerefentry><refentrytitle>systemd-veritysetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
34    units as necessary.</para>
35
36    <para>Currently, only two verity devices may be set up with this generator, backing the root and <filename>/usr</filename> file systems of the
37    OS.</para>
38
39    <para><filename>systemd-veritysetup-generator</filename> implements
40    <citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
41  </refsect1>
42
43  <refsect1>
44    <title>Kernel Command Line</title>
45
46    <para><filename>systemd-veritysetup-generator</filename>
47    understands the following kernel command line parameters:</para>
48
49    <variablelist class='kernel-commandline-options'>
50      <varlistentry>
51        <term><varname>systemd.verity=</varname></term>
52        <term><varname>rd.systemd.verity=</varname></term>
53
54        <listitem><para>Takes a boolean argument. Defaults to <literal>yes</literal>. If <literal>no</literal>,
55        disables the generator entirely. <varname>rd.systemd.verity=</varname> is honored only by the initial RAM disk
56        (initrd) while <varname>systemd.verity=</varname> is honored by both the host system and the
57        initrd.</para></listitem>
58      </varlistentry>
59
60      <varlistentry>
61        <term><varname>roothash=</varname></term>
62
63        <listitem><para>Takes a root hash value for the root file system. Expects a hash value formatted in hexadecimal
64        characters of the appropriate length (i.e. most likely 256 bit/64 characters, or longer). If not specified via
65        <varname>systemd.verity_root_data=</varname> and <varname>systemd.verity_root_hash=</varname>, the hash and
66        data devices to use are automatically derived from the specified hash value. Specifically, the data partition
67        device is looked for under a GPT partition UUID derived from the first 128bit of the root hash, the hash
68        partition device is looked for under a GPT partition UUID derived from the last 128bit of the root hash. Hence
69        it is usually sufficient to specify the root hash to boot from a verity protected root file system, as
70        device paths are automatically determined from it — as long as the partition table is properly set up.</para>
71        </listitem>
72      </varlistentry>
73
74      <varlistentry>
75        <term><varname>systemd.verity_root_data=</varname></term>
76        <term><varname>systemd.verity_root_hash=</varname></term>
77
78        <listitem><para>These two settings take block device paths as arguments and may be used to explicitly
79        configure the data partition and hash partition to use for setting up the verity protection for the root file
80        system. If not specified, these paths are automatically derived from the <varname>roothash=</varname> argument
81        (see above).</para></listitem>
82      </varlistentry>
83
84      <varlistentry>
85        <term><varname>systemd.verity_root_options=</varname></term>
86
87        <listitem><para>Takes a comma-separated list of dm-verity options. Expects the following options
88        <option>ignore-corruption</option>, <option>restart-on-corruption</option>, <option>ignore-zero-blocks</option>,
89        <option>check-at-most-once</option>, <option>panic-on-corruption</option> and
90        <option>root-hash-signature=<replaceable>PATH</replaceable>|base64:<replaceable>HEX</replaceable></option>. See
91        <citerefentry project='die-net'><refentrytitle>veritysetup</refentrytitle><manvolnum>8</manvolnum></citerefentry> for more
92        details.</para></listitem>
93      </varlistentry>
94
95      <varlistentry>
96        <term><varname>usrhash=</varname></term>
97        <term><varname>systemd.verity_usr_data=</varname></term>
98        <term><varname>systemd.verity_usr_hash=</varname></term>
99        <term><varname>systemd.verity_usr_options=</varname></term>
100
101        <listitem><para>Equivalent to their counterparts for the root file system as described above, but apply to the <filename>/usr/</filename> file system instead.</para></listitem>
102      </varlistentry>
103    </variablelist>
104  </refsect1>
105
106  <refsect1>
107    <title>See Also</title>
108    <para>
109      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
110      <citerefentry><refentrytitle>systemd-veritysetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
111      <citerefentry project='die-net'><refentrytitle>veritysetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
112      <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>
113    </para>
114  </refsect1>
115
116</refentry>
117