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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-10 20:49:52 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-10 20:49:52 +0000
commit55944e5e40b1be2afc4855d8d2baf4b73d1876b5 (patch)
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Adding upstream version 255.4.upstream/255.4
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+<?xml version="1.0"?>
+<!--*-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="integritytab" conditional='HAVE_LIBCRYPTSETUP' xmlns:xi="http://www.w3.org/2001/XInclude">
+
+ <refentryinfo>
+ <title>integritytab</title>
+ <productname>systemd</productname>
+ </refentryinfo>
+
+ <refmeta>
+ <refentrytitle>integritytab</refentrytitle>
+ <manvolnum>5</manvolnum>
+ </refmeta>
+
+ <refnamediv>
+ <refname>integritytab</refname>
+ <refpurpose>Configuration for integrity block devices</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <para><filename>/etc/integritytab</filename></para>
+ </refsynopsisdiv>
+
+ <refsect1>
+ <title>Description</title>
+
+ <para>The <filename>/etc/integritytab</filename> file describes
+ integrity protected block devices that are set up during
+ system boot.</para>
+
+ <para>Empty lines and lines starting with the <literal>#</literal>
+ character are ignored. Each of the remaining lines describes one
+ verity integrity protected block device. Fields are delimited by
+ white space.</para>
+
+ <para>Each line is in the form<programlisting><replaceable>volume-name</replaceable> <replaceable>block-device</replaceable>
+ <replaceable>[keyfile|-]</replaceable> <replaceable>[options|-]</replaceable></programlisting>
+ The first two fields are mandatory, the remaining two are optional and only required if user specified non-default options during integrity format.</para>
+
+ <para>The first field contains the name of the resulting integrity volume; its block device is set up
+ below <filename>/dev/mapper/</filename>.</para>
+
+ <para>The second field contains a path to the underlying block device, or a specification of a block device via
+ <literal>UUID=</literal> followed by the UUID,
+ <literal>PARTUUID=</literal> followed by the partition UUID,
+ <literal>LABEL=</literal> followed by the label,
+ <literal>PARTLABEL=</literal> followed by the partition label.
+ </para>
+
+ <para>The third field if present contains an absolute filename path to a key file or a <literal>-</literal>
+ to specify none. When the filename is present, the "integrity-algorithm" defaults to <literal>hmac-sha256</literal>
+ with the key length derived from the number of bytes in the key file. At this time the only supported integrity algorithm
+ when using key file is hmac-sha256. The maximum size of the key file is 4096 bytes.
+ </para>
+
+ <para>The fourth field, if present, is a comma-delimited list of options or a <literal>-</literal> to specify none. The following options are
+ recognized:</para>
+ <variablelist>
+
+ <varlistentry>
+ <term><option>allow-discards</option></term>
+
+ <listitem><para>
+ Allow the use of discard (TRIM) requests for the device.
+ This option is available since the Linux kernel version 5.7.
+ </para>
+
+ <xi:include href="version-info.xml" xpointer="v250"/></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>mode=(journal|bitmap|direct)</option></term>
+
+ <listitem><para>
+ Enable journaled, bitmapped or direct (passthrough) mode. Journaled mode is the default when this option is not specified.
+ It provides safety against crashes, but can be slow because all data has to be written twice.
+ Bitmap mode is more efficient since it requires only a single write, but it is less reliable because if data corruption happens when the machine crashes, it may not be detected.
+ Direct mode disables the journal and the bitmap. Corresponds to the "direct writes" mode documented in
+ <ulink url="https://docs.kernel.org/admin-guide/device-mapper/dm-integrity.html">the dm-integrity documentation</ulink>.
+ Note that without a journal, if there is a crash, it is possible that the integrity tags and data will not match. If used, the journal-*
+ options below will have no effect if passed.
+ </para>
+
+ <xi:include href="version-info.xml" xpointer="v254"/></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>journal-watermark=[0..100]%</option></term>
+
+ <listitem><para>
+ Journal watermark in percent. When the journal percentage exceeds this watermark, the journal flush will be started. Setting a value of
+ "0%" uses default value.
+ </para>
+
+ <xi:include href="version-info.xml" xpointer="v250"/></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>journal-commit-time=[0..N]</option></term>
+
+ <listitem><para>
+ Commit time in milliseconds. When this time passes (and no explicit flush operation was issued), the journal is written. Setting a value of
+ zero uses default value.
+ </para>
+
+ <xi:include href="version-info.xml" xpointer="v250"/></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>data-device=/dev/disk/by-...</option></term>
+
+ <listitem><para>
+ Specify a separate block device that contains existing data. The second field specified in the
+ integritytab for block device then will contain calculated integrity tags and journal for data-device,
+ but not the end user data.
+ </para>
+
+ <xi:include href="version-info.xml" xpointer="v250"/></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>integrity-algorithm=[crc32c|crc32|sha1|sha256|hmac-sha256]</option></term>
+
+ <listitem><para>
+ The algorithm used for integrity checking. The default is crc32c. Must match option used during format.
+ </para>
+
+ <xi:include href="version-info.xml" xpointer="v250"/></listitem>
+ </varlistentry>
+ </variablelist>
+
+ <para>At early boot and when the system manager configuration is
+ reloaded, this file is translated into native systemd units by
+ <citerefentry><refentrytitle>systemd-integritysetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
+ </refsect1>
+
+ <refsect1>
+ <title>Examples</title>
+ <example>
+ <title>/etc/integritytab</title>
+ <para>Set up two integrity protected block devices. </para>
+
+ <programlisting>home PARTUUID=4973d0b8-1b15-c449-96ec-94bab7f6a7b8 - journal-commit-time=10,allow-discards,journal-watermark=55%
+data PARTUUID=5d4b1808-be76-774d-88af-03c4c3a41761 - allow-discards
+</programlisting>
+ </example>
+
+ <example>
+ <title>/etc/integritytab</title>
+ <para>Set up 1 integrity protected block device using defaults </para>
+
+ <programlisting>home PARTUUID=4973d0b8-1b15-c449-96ec-94bab7f6a7b8</programlisting>
+ </example>
+
+ <example>
+ <title>/etc/integritytab</title>
+ <para>Set up 1 integrity device using existing data block device which contains user data </para>
+
+ <programlisting>home PARTUUID=4973d0b8-1b15-c449-96ec-94bab7f6a7b8 - data-device=/dev/disk/by-uuid/9276d9c0-d4e3-4297-b4ff-3307cd0d092f</programlisting>
+ </example>
+
+ <example>
+ <title>/etc/integritytab</title>
+ <para>Set up 1 integrity device using a HMAC key file using defaults </para>
+
+ <programlisting>home PARTUUID=4973d0b8-1b15-c449-96ec-94bab7f6a7b8 /etc/hmac.key</programlisting>
+ </example>
+
+ </refsect1>
+
+ <refsect1>
+ <title>See Also</title>
+ <para>
+ <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd-integritysetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd-integritysetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+ <citerefentry project='die-net'><refentrytitle>integritysetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+ </para>
+ </refsect1>
+
+</refentry>