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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></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></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></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></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></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>
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