Merge pull request #24412 from keszybz/man-similarly

[thirdparty/systemd.git] / man / systemd-measure.xml

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<!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
<refentry id="systemd-measure" xmlns:xi="http://www.w3.org/2001/XInclude" conditional='HAVE_GNU_EFI'>

  <refentryinfo>
    <title>systemd-measure</title>
    <productname>systemd</productname>
  </refentryinfo>

  <refmeta>
    <refentrytitle>systemd-measure</refentrytitle>
    <manvolnum>1</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>systemd-measure</refname>
    <refpurpose>Pre-calculate expected TPM2 PCR values for booted unified kernel images</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <cmdsynopsis>
      <command>/usr/lib/systemd/systemd-measure <arg choice="opt" rep="repeat">OPTIONS</arg></command>
    </cmdsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para>Note: this command is experimental for now. While it is likely to become a regular component of
    systemd, it might still change in behaviour and interface.</para>

    <para><command>systemd-measure</command> is a tool that may be used to pre-calculate the expected TPM2
    PCR 11 values that should be seen when a unified Linux kernel image based on
    <citerefentry><refentrytitle>systemd-stub</refentrytitle><manvolnum>7</manvolnum></citerefentry> is
    booted up. It accepts paths to the ELF kernel image file, initial ram disk image file, devicetree file,
    kernel command line file,
    <citerefentry><refentrytitle>os-release</refentrytitle><manvolnum>5</manvolnum></citerefentry> file, and
    boot splash file that make up the unified kernel image, and determines the PCR values expected to be in
    place after booting the image. Calculation starts with a zero-initialized PCR 11, and is executed in a
    fashion compatible with what <filename>systemd-stub</filename> does at boot.</para>
  </refsect1>

  <refsect1>
    <title>Commands</title>

    <para>The following commands are understood:</para>

    <variablelist>
      <varlistentry>
        <term><command>status</command></term>

        <listitem><para>This is the default command if none is specified. This queries the local system's
        TPM2 PCR 11+12+13 values and displays them. The data is written in a similar format as the
        <command>calculate</command> command below, and may be used to quickly compare expectation with
        reality.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>calculate</command></term>

        <listitem><para>Pre-calculate the expected value seen in PCR register 11 after boot-up of a unified
        kernel image consisting of the components specified with <option>--linux=</option>,
        <option>--osrel=</option>, <option>--cmdline=</option>, <option>--initrd=</option>,
        <option>--splash=</option>, <option>--dtb=</option>, see below. Only <option>--linux=</option> is
        mandatory.</para></listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Options</title>

    <para>The following options are understood:</para>

    <variablelist>
      <varlistentry>
        <term><option>--linux=PATH</option></term>
        <term><option>--osrel=PATH</option></term>
        <term><option>--cmdline=PATH</option></term>
        <term><option>--initrd=PATH</option></term>
        <term><option>--splash=PATH</option></term>
        <term><option>--dtb=PATH</option></term>

        <listitem><para>When used with the <command>calculate</command> verb, configures the files to read
        the unified kernel image components from. Each option corresponds with the equally named section in
        the unified kernel PE file. The <option>--linux=</option> switch expects the path to the ELF kernel
        file that the unified PE kernel will wrap. All switches except <option>--linux=</option> are
        optional. Each option may be used at most once.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--current</option></term>
        <listitem><para>When used with the <command>calculate</command> verb, takes the PCR 11 values
        currently in effect for the system (which should typically reflect the hashes of the currently booted
        kernel). This can be used in place of <option>--linux=</option> and the other switches listed
        above.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--bank=DIGEST</option></term>

        <listitem><para>Controls the PCR banks to pre-calculate the PCR values for – in case
        <command>calculate</command> is invoked –, or the banks to show in the <command>status</command>
        output. May be used more then once to specify multiple banks. If not specified, defaults to the four
        banks <literal>sha1</literal>, <literal>sha256</literal>, <literal>sha384</literal>,
        <literal>sha512</literal>.</para></listitem>
      </varlistentry>

      <xi:include href="standard-options.xml" xpointer="json" />
      <xi:include href="standard-options.xml" xpointer="no-pager" />
      <xi:include href="standard-options.xml" xpointer="help" />
      <xi:include href="standard-options.xml" xpointer="version" />
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Examples</title>

    <example>
      <title>Generate a unified kernel image, and calculate the expected TPM PCR 11 value</title>

      <programlisting># objcopy \
    --add-section .linux=vmlinux --change-section-vma .linux=0x2000000 \
    --add-section .osrel=os-release.txt --change-section-vma .osrel=0x20000 \
    --add-section .cmdline=cmdline.txt --change-section-vma .cmdline=0x30000 \
    --add-section .initrd=initrd.cpio --change-section-vma .initrd=0x3000000 \
    --add-section .splash=splash.bmp --change-section-vma .splash=0x100000 \
    --add-section .dtb=devicetree.dtb --change-section-vma .dtb=0x40000 \
    /usr/lib/systemd/boot/efi/linuxx64.efi.stub \
    foo.efi
# systemd-measure calculate \
     --linux=vmlinux \
     --osrel=os-release \
     --cmdline=cmdline.txt \
     --initrd=initrd.cpio \
     --splash=splash.bmp \
     --dtb=devicetree.dtb
11:sha1=d775a7b4482450ac77e03ee19bda90bd792d6ec7
11:sha256=bc6170f9ce28eb051ab465cd62be8cf63985276766cf9faf527ffefb66f45651
11:sha384=1cf67dff4757e61e5a73d2a21a6694d668629bbc3761747d493f7f49ad720be02fd07263e1f93061243aec599d1ee4b4
11:sha512=8e79acd3ddbbc8282e98091849c3530f996303c8ac8e87a3b2378b71c8b3a6e86d5c4f41ecea9e1517090c3e8ec0c714821032038f525f744960bcd082d937da
</programlisting>
    </example>
  </refsect1>

  <refsect1>
    <title>Exit status</title>

    <para>On success, 0 is returned, a non-zero failure code otherwise.</para>
  </refsect1>

  <refsect1>
    <title>See Also</title>
    <para>
      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd-stub</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
      <citerefentry project='man-pages'><refentrytitle>objcopy</refentrytitle><manvolnum>1</manvolnum></citerefentry>
     </para>
  </refsect1>

</refentry>