man/systemd-veritysetup-generator.xml

   1 <?xml version="1.0"?>
   2 <!--*-nxml-*-->
   3 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   4   "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd">
   5 <!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
   6 <refentry id="systemd-veritysetup-generator" conditional='HAVE_LIBCRYPTSETUP'
   7           xmlns:xi="http://www.w3.org/2001/XInclude">
   8
   9   <refentryinfo>
  10     <title>systemd-veritysetup-generator</title>
  11     <productname>systemd</productname>
  12   </refentryinfo>
  13
  14   <refmeta>
  15     <refentrytitle>systemd-veritysetup-generator</refentrytitle>
  16     <manvolnum>8</manvolnum>
  17   </refmeta>
  18
  19   <refnamediv>
  20     <refname>systemd-veritysetup-generator</refname>
  21     <refpurpose>Unit generator for verity protected block devices</refpurpose>
  22   </refnamediv>
  23
  24   <refsynopsisdiv>
  25     <para><filename>/usr/lib/systemd/system-generators/systemd-veritysetup-generator</filename></para>
  26   </refsynopsisdiv>
  27
  28   <refsect1>
  29     <title>Description</title>
  30
  31     <para><command>systemd-veritysetup-generator</command> is a generator that translates kernel command line
  32     options configuring verity protected block devices into native systemd units early at boot and when
  33     configuration of the system manager is reloaded. This will create
  34     <citerefentry><refentrytitle>systemd-veritysetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
  35     units as necessary.</para>
  36
  37     <para>Currently, only two verity devices may be set up with this generator, backing the root and <filename>/usr</filename> file systems of the
  38     OS.</para>
  39
  40     <para><command>systemd-veritysetup-generator</command> implements
  41     <citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
  42   </refsect1>
  43
  44   <refsect1>
  45     <title>Kernel Command Line</title>
  46
  47     <para><command>systemd-veritysetup-generator</command>
  48     understands the following kernel command line parameters:</para>
  49
  50     <variablelist class='kernel-commandline-options'>
  51       <varlistentry>
  52         <term><varname>systemd.verity=</varname></term>
  53         <term><varname>rd.systemd.verity=</varname></term>
  54
  55         <listitem><para>Takes a boolean argument. Defaults to <literal>yes</literal>. If
  56         <literal>no</literal>, disables the generator entirely. <varname>rd.systemd.verity=</varname> is
  57         honored only in the initrd while <varname>systemd.verity=</varname> is honored by both the main
  58         system and in the initrd.</para>
  59
  60         <xi:include href="version-info.xml" xpointer="v233"/></listitem>
  61       </varlistentry>
  62
  63       <varlistentry>
  64         <term><varname>veritytab=</varname></term>
  65         <term><varname>rd.veritytab=</varname></term>
  66
  67         <listitem><para>Takes a boolean argument. Defaults to <literal>yes</literal>. If
  68         <literal>no</literal>, causes the generator to ignore any devices configured in
  69         <filename>/etc/veritytab</filename>. <varname>rd.veritytab=</varname> is honored only in the initrd
  70         while <varname>veritytab=</varname> is honored by both the main system and in the initrd.</para>
  71
  72         <xi:include href="version-info.xml" xpointer="v248"/></listitem>
  73       </varlistentry>
  74
  75       <varlistentry>
  76         <term><varname>roothash=</varname></term>
  77
  78         <listitem><para>Takes a root hash value for the root file system. Expects a hash value formatted in hexadecimal
  79         characters of the appropriate length (i.e. most likely 256 bit/64 characters, or longer). If not specified via
  80         <varname>systemd.verity_root_data=</varname> and <varname>systemd.verity_root_hash=</varname>, the hash and
  81         data devices to use are automatically derived from the specified hash value. Specifically, the data partition
  82         device is looked for under a GPT partition UUID derived from the first 128-bit of the root hash, the hash
  83         partition device is looked for under a GPT partition UUID derived from the last 128-bit of the root hash. Hence
  84         it is usually sufficient to specify the root hash to boot from a verity protected root file system, as
  85         device paths are automatically determined from it — as long as the partition table is properly set up.</para>
  86
  87         <xi:include href="version-info.xml" xpointer="v233"/>
  88         </listitem>
  89       </varlistentry>
  90
  91       <varlistentry>
  92         <term><varname>systemd.verity_root_data=</varname></term>
  93         <term><varname>systemd.verity_root_hash=</varname></term>
  94
  95         <listitem><para>These two settings take block device paths as arguments and may be used to explicitly
  96         configure the data partition and hash partition to use for setting up the verity protection for the root file
  97         system. If not specified, these paths are automatically derived from the <varname>roothash=</varname> argument
  98         (see above).</para>
  99
 100         <xi:include href="version-info.xml" xpointer="v233"/></listitem>
 101       </varlistentry>
 102
 103       <varlistentry>
 104         <term><varname>systemd.verity_root_options=</varname></term>
 105
 106         <listitem><para>Takes a comma-separated list of dm-verity options. Expects the following options
 107         <option>superblock=<replaceable>BOOLEAN</replaceable></option>,
 108         <option>format=<replaceable>NUMBER</replaceable></option>,
 109         <option>data-block-size=<replaceable>BYTES</replaceable></option>,
 110         <option>hash-block-size=<replaceable>BYTES</replaceable></option>,
 111         <option>data-blocks=<replaceable>BLOCKS</replaceable></option>,
 112         <option>hash-offset=<replaceable>BYTES</replaceable></option>,
 113         <option>salt=<replaceable>HEX</replaceable></option>, <option>uuid=<replaceable>UUID</replaceable></option>,
 114         <option>ignore-corruption</option>, <option>restart-on-corruption</option>, <option>ignore-zero-blocks</option>,
 115         <option>check-at-most-once</option>, <option>panic-on-corruption</option>,
 116         <option>hash=<replaceable>HASH</replaceable></option>, <option>fec-device=<replaceable>PATH</replaceable></option>,
 117         <option>fec-offset=<replaceable>BYTES</replaceable></option>, <option>fec-roots=<replaceable>NUM</replaceable></option> and
 118         <option>root-hash-signature=<replaceable>PATH</replaceable>|base64:<replaceable>HEX</replaceable></option>. See
 119         <citerefentry project='man-pages'><refentrytitle>veritysetup</refentrytitle><manvolnum>8</manvolnum></citerefentry> for more
 120         details.</para>
 121
 122         <xi:include href="version-info.xml" xpointer="v248"/></listitem>
 123       </varlistentry>
 124
 125       <varlistentry>
 126         <term><varname>usrhash=</varname></term>
 127         <term><varname>systemd.verity_usr_data=</varname></term>
 128         <term><varname>systemd.verity_usr_hash=</varname></term>
 129         <term><varname>systemd.verity_usr_options=</varname></term>
 130
 131         <listitem><para>Equivalent to their counterparts for the root file system as described above, but
 132         apply to the <filename>/usr/</filename> file system instead.</para>
 133
 134         <xi:include href="version-info.xml" xpointer="v250"/></listitem>
 135       </varlistentry>
 136     </variablelist>
 137   </refsect1>
 138
 139   <refsect1>
 140     <title>See Also</title>
 141     <para><simplelist type="inline">
 142       <member><citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
 143       <member><citerefentry><refentrytitle>systemd-veritysetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
 144       <member><citerefentry project='man-pages'><refentrytitle>veritysetup</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
 145       <member><citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
 146     </simplelist></para>
 147   </refsect1>
 148
 149 </refentry>