man/systemd-veritysetup-generator.xml

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   5   SPDX-License-Identifier: LGPL-2.1+
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   7 <refentry id="systemd-veritysetup-generator" conditional='HAVE_LIBCRYPTSETUP'>
   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 integrity 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><filename>systemd-veritysetup-generator</filename> is a generator that translates kernel command line options
  32     configuring integrity protected block devices (verity) 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 a single verity device may be se up with this generator, backing the root file system of the
  38     OS.</para>
  39
  40     <para><filename>systemd-veritysetup-generator</filename> 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><filename>systemd-veritysetup-generator</filename>
  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 <literal>no</literal>,
  56         disables the generator entirely. <varname>rd.systemd.verity=</varname> is honored only by the initial RAM disk
  57         (initrd) while <varname>systemd.verity=</varname> is honored by both the host system and the
  58         initrd. </para></listitem>
  59       </varlistentry>
  60
  61       <varlistentry>
  62         <term><varname>roothash=</varname></term>
  63
  64         <listitem><para>Takes a root hash value for the root file system. Expects a hash value formatted in hexadecimal
  65         characters, of the appropriate length (i.e. most likely 256 bit/64 characters, or longer). If not specified via
  66         <varname>systemd.verity_root_data=</varname> and <varname>systemd.verity_root_hash=</varname>, the hash and
  67         data devices to use are automatically derived from the specified hash value. Specifically, the data partition
  68         device is looked for under a GPT partition UUID derived from the first 128bit of the root hash, the hash
  69         partition device is looked for under a GPT partition UUID derived from the last 128bit of the root hash. Hence
  70         it is usually sufficient to specify the root hash to boot from an integrity protected root file system, as
  71         device paths are automatically determined from it — as long as the partition table is properly set up.</para>
  72         </listitem>
  73       </varlistentry>
  74
  75       <varlistentry>
  76         <term><varname>systemd.verity_root_data=</varname></term>
  77         <term><varname>systemd.verity_root_hash=</varname></term>
  78
  79         <listitem><para>These two settings take block device paths as arguments, and may be use to explicitly configure
  80         the data partition and hash partition to use for setting up the integrity protection for the root file
  81         system. If not specified, these paths are automatically derived from the <varname>roothash=</varname> argument
  82         (see above).</para></listitem>
  83       </varlistentry>
  84
  85     </variablelist>
  86   </refsect1>
  87
  88   <refsect1>
  89     <title>See Also</title>
  90     <para>
  91       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
  92       <citerefentry><refentrytitle>systemd-veritysetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
  93       <citerefentry project='die-net'><refentrytitle>veritysetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
  94       <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>
  95     </para>
  96   </refsect1>
  97
  98 </refentry>