mirror of
https://github.com/systemd/systemd-stable.git
synced 2024-10-30 06:25:25 +03:00
316 lines
15 KiB
XML
316 lines
15 KiB
XML
<?xml version="1.0"?>
|
|
<!--*-nxml-*-->
|
|
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
|
|
<!--
|
|
This file is part of systemd.
|
|
|
|
Copyright 2012 Lennart Poettering
|
|
|
|
systemd is free software; you can redistribute it and/or modify it
|
|
under the terms of the GNU Lesser General Public License as published by
|
|
the Free Software Foundation; either version 2.1 of the License, or
|
|
(at your option) any later version.
|
|
|
|
systemd is distributed in the hope that it will be useful, but
|
|
WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public License
|
|
along with systemd; If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
This is based on crypttab(5) from Fedora's initscripts package, which in
|
|
turn is based on Debian's version.
|
|
|
|
The Red Hat version has been written by Miloslav Trmac <mitr@redhat.com>.
|
|
|
|
-->
|
|
<refentry id="crypttab" conditional='HAVE_LIBCRYPTSETUP'>
|
|
|
|
<refentryinfo>
|
|
<title>crypttab</title>
|
|
<productname>systemd</productname>
|
|
|
|
<authorgroup>
|
|
<author>
|
|
<contrib>Documentation</contrib>
|
|
<firstname>Miloslav</firstname>
|
|
<surname>Trmac</surname>
|
|
<email>mitr@redhat.com</email>
|
|
</author>
|
|
<author>
|
|
<contrib>Documentation</contrib>
|
|
<firstname>Lennart</firstname>
|
|
<surname>Poettering</surname>
|
|
<email>lennart@poettering.net</email>
|
|
</author>
|
|
</authorgroup>
|
|
</refentryinfo>
|
|
|
|
<refmeta>
|
|
<refentrytitle>crypttab</refentrytitle>
|
|
<manvolnum>5</manvolnum>
|
|
</refmeta>
|
|
|
|
<refnamediv>
|
|
<refname>crypttab</refname>
|
|
<refpurpose>Configuration for encrypted block devices</refpurpose>
|
|
</refnamediv>
|
|
|
|
<refsynopsisdiv>
|
|
<para><filename>/etc/crypttab</filename></para>
|
|
</refsynopsisdiv>
|
|
|
|
<refsect1>
|
|
<title>Description</title>
|
|
|
|
<para>The <filename>/etc/crypttab</filename> file
|
|
describes encrypted block devices that are set up
|
|
during system boot.</para>
|
|
|
|
<para>Empty lines and lines starting with the #
|
|
character are ignored. Each of the remaining lines
|
|
describes one encrypted block device, fields on the
|
|
line are delimited by white space. The first two
|
|
fields are mandatory, the remaining two are
|
|
optional.</para>
|
|
|
|
<para>The first field contains the name of the
|
|
resulting encrypted block device; the device is set up
|
|
within <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. If the block device contains a LUKS signature,
|
|
it is opened as a LUKS encrypted partition; otherwise
|
|
it is assumed to be a raw dm-crypt partition.</para>
|
|
|
|
<para>The third field specifies the encryption
|
|
password. If the field is not present or the password
|
|
is set to none, the password has to be manually
|
|
entered during system boot. Otherwise the field is
|
|
interpreted as a path to a file containing the
|
|
encryption password. For swap encryption
|
|
<filename>/dev/urandom</filename> or the hardware
|
|
device <filename>/dev/hw_random</filename> can be used
|
|
as the password file; using
|
|
<filename>/dev/random</filename> may prevent boot
|
|
completion if the system does not have enough entropy
|
|
to generate a truly random encryption key.</para>
|
|
|
|
<para>The fourth field, if present, is a
|
|
comma-delimited list of options. The following
|
|
options are recognized:</para>
|
|
|
|
<variablelist class='crypttab-options'>
|
|
<varlistentry>
|
|
<term><varname>cipher=</varname></term>
|
|
|
|
<listitem><para>Specifies the cipher
|
|
to use; see
|
|
<citerefentry><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
|
|
for possible values and the default
|
|
value of this option. A cipher with
|
|
unpredictable IV values, such as
|
|
<literal>aes-cbc-essiv:sha256</literal>,
|
|
is recommended. </para></listitem>
|
|
</varlistentry>
|
|
|
|
|
|
<varlistentry>
|
|
<term><varname>size=</varname></term>
|
|
|
|
<listitem><para>Specifies the key size
|
|
in bits; see
|
|
<citerefentry><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
|
|
for possible values and the default
|
|
value of this
|
|
option. </para></listitem>
|
|
</varlistentry>
|
|
|
|
|
|
<varlistentry>
|
|
<term><varname>keyfile-size=</varname></term>
|
|
|
|
<listitem><para>Specifies the maximum number
|
|
of bytes to read from the keyfile; see
|
|
<citerefentry><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
|
|
for possible values and the default
|
|
value of this option. This option is ignored
|
|
in plain encryption mode, as the keyfile-size is then given by the key size.</para></listitem>
|
|
</varlistentry>
|
|
|
|
|
|
<varlistentry>
|
|
<term><varname>keyfile-offset=</varname></term>
|
|
|
|
<listitem><para>Specifies the number
|
|
of bytes to skip at the start of
|
|
the keyfile; see
|
|
<citerefentry><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
|
|
for possible values and the default
|
|
value of this option.</para></listitem>
|
|
</varlistentry>
|
|
|
|
|
|
<varlistentry>
|
|
<term><varname>hash=</varname></term>
|
|
|
|
<listitem><para>Specifies the hash to
|
|
use for password hashing; see
|
|
<citerefentry><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry> for possible values and
|
|
the default value of this
|
|
option. </para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>tries=</varname></term>
|
|
|
|
<listitem><para>Specifies the maximum
|
|
number of times the user is queried
|
|
for a password.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>verify</varname></term>
|
|
|
|
<listitem><para> If the encryption
|
|
password is read from console, it has
|
|
to be entered twice (to prevent
|
|
typos). </para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>read-only</varname></term><term><varname>readonly</varname></term>
|
|
|
|
<listitem><para>Set up the encrypted
|
|
block device in read-only
|
|
mode.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>allow-discards</varname></term>
|
|
|
|
<listitem><para>Allow discard requests
|
|
to be passed through the encrypted
|
|
block device. This improves
|
|
performance on SSD storage but has
|
|
security
|
|
implications.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>luks</varname></term>
|
|
|
|
<listitem><para>Force LUKS mode.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>plain</varname></term>
|
|
|
|
<listitem><para>Force plain encryption
|
|
mode.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>timeout=</varname></term>
|
|
|
|
<listitem><para>Specify the timeout
|
|
for querying for a password. If no
|
|
unit is specified seconds is used.
|
|
Supported units are s, ms, us, min, h,
|
|
d. A timeout of 0 waits indefinitely
|
|
(which is the
|
|
default).</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>noauto</varname></term>
|
|
|
|
<listitem><para> This device will not
|
|
be automatically unlocked on
|
|
boot. </para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>nofail</varname></term>
|
|
|
|
<listitem><para>The system will not
|
|
wait for the device to show up and be
|
|
unlocked at boot, and not fail the
|
|
boot if it doesn't show
|
|
up.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>swap</varname></term>
|
|
|
|
<listitem><para> The encrypted block
|
|
device will be used as a swap
|
|
partition, and will be formatted as a
|
|
swap partition after setting up the
|
|
encrypted block device, with
|
|
<citerefentry><refentrytitle>mkswap</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
|
|
|
|
<para>WARNING: Using the
|
|
<varname>swap</varname> option will
|
|
destroy the contents of the named
|
|
partition during every boot, so make
|
|
sure the underlying block device is
|
|
specified
|
|
correctly. </para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>tmp</varname></term>
|
|
|
|
<listitem><para>The encrypted block
|
|
device will be prepared for using it
|
|
as <filename>/tmp</filename>
|
|
partition: it will be formatted using
|
|
<citerefentry><refentrytitle>mke2fs</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
|
|
|
|
<para>WARNING: Using the
|
|
<varname>tmp</varname> option will
|
|
destroy the contents of the named
|
|
partition during every boot, so make
|
|
sure the underlying block device is
|
|
specified
|
|
correctly. </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-cryptsetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Example</title>
|
|
<example>
|
|
<title>/etc/crypttab example</title>
|
|
<para>Set up two encrypted block devices with
|
|
LUKS: one normal one for storage, and another
|
|
one for usage as swap device.</para>
|
|
|
|
<programlisting>luks-2505567a-9e27-4efe-a4d5-15ad146c258b UUID=2505567a-9e27-4efe-a4d5-15ad146c258b - timeout=0
|
|
swap /dev/sda7 /dev/urandom swap</programlisting>
|
|
</example>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>See Also</title>
|
|
<para>
|
|
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd-cryptsetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd-cryptsetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>mkswap</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>mke2fs</refentrytitle><manvolnum>8</manvolnum></citerefentry>
|
|
</para>
|
|
</refsect1>
|
|
|
|
</refentry>
|