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 by the initrd while <varname>systemd.verity=</varname> is honored by both the host
  58         system and the initrd.</para>
  59
  60         <xi:include href="version-info.xml" xpointer="v233"/></listitem>
  61       </varlistentry>
  62
  63       <varlistentry>
  64         <term><varname>roothash=</varname></term>
  65
  66         <listitem><para>Takes a root hash value for the root file system. Expects a hash value formatted in hexadecimal
  67         characters of the appropriate length (i.e. most likely 256 bit/64 characters, or longer). If not specified via
  68         <varname>systemd.verity_root_data=</varname> and <varname>systemd.verity_root_hash=</varname>, the hash and
  69         data devices to use are automatically derived from the specified hash value. Specifically, the data partition
  70         device is looked for under a GPT partition UUID derived from the first 128-bit of the root hash, the hash
  71         partition device is looked for under a GPT partition UUID derived from the last 128-bit of the root hash. Hence
  72         it is usually sufficient to specify the root hash to boot from a verity protected root file system, as
  73         device paths are automatically determined from it — as long as the partition table is properly set up.</para>
  74
  75         <xi:include href="version-info.xml" xpointer="v233"/>
  76         </listitem>
  77       </varlistentry>
  78
  79       <varlistentry>
  80         <term><varname>systemd.verity_root_data=</varname></term>
  81         <term><varname>systemd.verity_root_hash=</varname></term>
  82
  83         <listitem><para>These two settings take block device paths as arguments and may be used to explicitly
  84         configure the data partition and hash partition to use for setting up the verity protection for the root file
  85         system. If not specified, these paths are automatically derived from the <varname>roothash=</varname> argument
  86         (see above).</para>
  87
  88         <xi:include href="version-info.xml" xpointer="v233"/></listitem>
  89       </varlistentry>
  90
  91       <varlistentry>
  92         <term><varname>systemd.verity_root_options=</varname></term>
  93
  94         <listitem><para>Takes a comma-separated list of dm-verity options. Expects the following options
  95         <option>superblock=<replaceable>BOOLEAN</replaceable></option>,
  96         <option>format=<replaceable>NUMBER</replaceable></option>,
  97         <option>data-block-size=<replaceable>BYTES</replaceable></option>,
  98         <option>hash-block-size=<replaceable>BYTES</replaceable></option>,
  99         <option>data-blocks=<replaceable>BLOCKS</replaceable></option>,
 100         <option>hash-offset=<replaceable>BYTES</replaceable></option>,
 101         <option>salt=<replaceable>HEX</replaceable></option>, <option>uuid=<replaceable>UUID</replaceable></option>,
 102         <option>ignore-corruption</option>, <option>restart-on-corruption</option>, <option>ignore-zero-blocks</option>,
 103         <option>check-at-most-once</option>, <option>panic-on-corruption</option>,
 104         <option>hash=<replaceable>HASH</replaceable></option>, <option>fec-device=<replaceable>PATH</replaceable></option>,
 105         <option>fec-offset=<replaceable>BYTES</replaceable></option>, <option>fec-roots=<replaceable>NUM</replaceable></option> and
 106         <option>root-hash-signature=<replaceable>PATH</replaceable>|base64:<replaceable>HEX</replaceable></option>. See
 107         <citerefentry project='die-net'><refentrytitle>veritysetup</refentrytitle><manvolnum>8</manvolnum></citerefentry> for more
 108         details.</para>
 109
 110         <xi:include href="version-info.xml" xpointer="v248"/></listitem>
 111       </varlistentry>
 112
 113       <varlistentry>
 114         <term><varname>usrhash=</varname></term>
 115         <term><varname>systemd.verity_usr_data=</varname></term>
 116         <term><varname>systemd.verity_usr_hash=</varname></term>
 117         <term><varname>systemd.verity_usr_options=</varname></term>
 118
 119         <listitem><para>Equivalent to their counterparts for the root file system as described above, but
 120         apply to the <filename>/usr/</filename> file system instead.</para>
 121
 122         <xi:include href="version-info.xml" xpointer="v250"/></listitem>
 123       </varlistentry>
 124     </variablelist>
 125   </refsect1>
 126
 127   <refsect1>
 128     <title>See Also</title>
 129     <para><simplelist type="inline">
 130       <member><citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
 131       <member><citerefentry><refentrytitle>systemd-veritysetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
 132       <member><citerefentry project='die-net'><refentrytitle>veritysetup</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
 133       <member><citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
 134     </simplelist></para>
 135   </refsect1>
 136
 137 </refentry>