<?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">
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//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/>.
+ SPDX-License-Identifier: LGPL-2.1+
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 <literal>#</literal>
- 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>Setting up encrypted block devices using this file
- supports three encryption modes: LUKS, TrueCrypt and plain.
- See <citerefentry><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
- for more information about each mode. When no mode is specified
- in the options field and the block device contains a LUKS
- signature, it is opened as a LUKS device; otherwise, it is
- assumed to be in raw dm-crypt (plain mode) format.</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 file, or a specification of a block
- device via <literal>UUID=</literal> followed by the
- UUID.</para>
-
- <para>The third field specifies the encryption
- password. If the field is not present or the password
- is set to <literal>none</literal> or <literal>-</literal>,
- the password has to be manually entered during system boot.
- Otherwise, the field is interpreted as a absolute 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='fstab-options'>
-
- <varlistentry>
- <term><option>discard</option></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><option>cipher=</option></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><option>hash=</option></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><option>header=</option></term>
-
- <listitem><para>Use a detached (separated)
- metadata device or file where the LUKS header
- is stored. This option is only relevant for
- LUKS devices. See
- <citerefentry><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
- for possible values and the default value of
- this option.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><option>keyfile-offset=</option></term>
-
- <listitem><para>Specifies the number of bytes to
- skip at the start of the key file. See
- <citerefentry><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
- for possible values and the default value of
- this option.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><option>keyfile-size=</option></term>
-
- <listitem><para>Specifies the maximum number
- of bytes to read from the key file. 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 key file size is then
- given by the key size.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><option>key-slot=</option></term>
-
- <listitem><para>Specifies the key slot to
- compare the passphrase or key against.
- If the key slot does not match the given
- passphrase or key, but another would, the
- setup of the device will fail regardless.
- This option implies <option>luks</option>. See
- <citerefentry><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
- for possible values. The default is to try
- all key slots in sequential order.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><option>luks</option></term>
-
- <listitem><para>Force LUKS mode. When this mode
- is used, the following options are ignored since
- they are provided by the LUKS header on the
- device: <option>cipher=</option>,
- <option>hash=</option>,
- <option>size=</option>.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><option>noauto</option></term>
-
- <listitem><para>This device will not be
- automatically unlocked on boot.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><option>nofail</option></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 does not show up.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><option>plain</option></term>
-
- <listitem><para>Force plain encryption mode.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><option>read-only</option></term><term><option>readonly</option></term>
-
- <listitem><para>Set up the encrypted block
- device in read-only mode.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><option>size=</option></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><option>swap</option></term>
-
- <listitem><para>The encrypted block device will
- be used as a swap device, and will be formatted
- accordingly after setting up the encrypted
- block device, with
- <citerefentry project='man-pages'><refentrytitle>mkswap</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
- This option implies <option>plain</option>.</para>
-
- <para>WARNING: Using the <option>swap</option>
- 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><option>tcrypt</option></term>
-
- <listitem><para>Use TrueCrypt encryption mode.
- When this mode is used, the following options are
- ignored since they are provided by the TrueCrypt
- header on the device or do not apply:
- <option>cipher=</option>,
- <option>hash=</option>,
- <option>keyfile-offset=</option>,
- <option>keyfile-size=</option>,
- <option>size=</option>.</para>
-
- <para>When this mode is used, the passphrase is
- read from the key file given in the third field.
- Only the first line of this file is read,
- excluding the new line character.</para>
-
- <para>Note that the TrueCrypt format uses both
- passphrase and key files to derive a password
- for the volume. Therefore, the passphrase and
- all key files need to be provided. Use
- <option>tcrypt-keyfile=</option> to provide
- the absolute path to all key files. When using
- an empty passphrase in combination with one or
- more key files, use <literal>/dev/null</literal>
- as the password file in the third field.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><option>tcrypt-hidden</option></term>
-
- <listitem><para>Use the hidden TrueCrypt volume.
- This option implies <option>tcrypt</option>.</para>
-
- <para>This will map the hidden volume that is
- inside of the volume provided in the second
- field. Please note that there is no protection
- for the hidden volume if the outer volume is
- mounted instead. See
- <citerefentry><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
- for more information on this limitation.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><option>tcrypt-keyfile=</option></term>
-
- <listitem><para>Specifies the absolute path to a
- key file to use for a TrueCrypt volume. This
- implies <option>tcrypt</option> and can be
- used more than once to provide several key
- files.</para>
-
- <para>See the entry for <option>tcrypt</option>
- on the behavior of the passphrase and key files
- when using TrueCrypt encryption mode.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><option>tcrypt-system</option></term>
-
- <listitem><para>Use TrueCrypt in system
- encryption mode. This option implies
- <option>tcrypt</option>.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><option>timeout=</option></term>
-
- <listitem><para>Specifies 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><option>x-systemd.device-timeout=</option></term>
-
- <listitem><para>Specifies how long
- systemd should wait for a device to
- show up before giving up on the
- entry. The argument is a time in
- seconds or explicitly specifified
- units of <literal>s</literal>,
- <literal>min</literal>,
- <literal>h</literal>,
- <literal>ms</literal>.
- </para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><option>tmp</option></term>
-
- <listitem><para>The encrypted block device will
- be prepared for using it as <filename>/tmp</filename>;
- it will be formatted using
- <citerefentry project='man-pages'><refentrytitle>mke2fs</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
- This option implies <option>plain</option>.</para>
-
- <para>WARNING: Using the <option>tmp</option>
- 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><option>tries=</option></term>
-
- <listitem><para>Specifies the maximum number of
- times the user is queried for a password.
- The default is 3. If set to 0, the user is
- queried for a password indefinitely.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><option>verify</option></term>
-
- <listitem><para> If the encryption password is
- read from console, it has to be entered twice to
- prevent typos.</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 four encrypted block devices. One using
- LUKS for normal storage, another one for usage as a swap
- device and two TrueCrypt volumes.</para>
-
- <programlisting>luks UUID=2505567a-9e27-4efe-a4d5-15ad146c258b
-swap /dev/sda7 /dev/urandom swap
+ <refentryinfo>
+ <title>crypttab</title>
+ <productname>systemd</productname>
+ </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 <literal>#</literal>
+ character are ignored. Each of the remaining lines describes one
+ encrypted block device. Fields are delimited by white space.</para>
+
+ <para>Each line is in the form<programlisting><replaceable>name</replaceable> <replaceable>encrypted-device</replaceable> <replaceable>password</replaceable> <replaceable>options</replaceable></programlisting>
+ The first two fields are mandatory, the remaining two are
+ optional.</para>
+
+ <para>Setting up encrypted block devices using this file supports
+ three encryption modes: LUKS, TrueCrypt and plain. See
+ <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+ for more information about each mode. When no mode is specified in
+ the options field and the block device contains a LUKS signature,
+ it is opened as a LUKS device; otherwise, it is assumed to be in
+ raw dm-crypt (plain mode) format.</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 file, or a specification of a block device via
+ <literal>UUID=</literal> followed by the UUID.</para>
+
+ <para>The third field specifies the encryption password. If the
+ field is not present or the password is set to
+ <literal>none</literal> or <literal>-</literal>, the password has
+ to be manually entered during system boot. Otherwise, the field is
+ interpreted as an absolute 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='fstab-options'>
+
+ <varlistentry>
+ <term><option>cipher=</option></term>
+
+ <listitem><para>Specifies the cipher to use. See
+ <citerefentry project='die-net'><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><option>discard</option></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><option>hash=</option></term>
+
+ <listitem><para>Specifies the hash to use for password
+ hashing. See
+ <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+ for possible values and the default value of this
+ option.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>header=</option></term>
+
+ <listitem><para>Use a detached (separated) metadata device or
+ file where the LUKS header is stored. This option is only
+ relevant for LUKS devices. See
+ <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+ for possible values and the default value of this
+ option.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>keyfile-offset=</option></term>
+
+ <listitem><para>Specifies the number of bytes to skip at the
+ start of the key file. See
+ <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+ for possible values and the default value of this
+ option.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>keyfile-size=</option></term>
+
+ <listitem><para>Specifies the maximum number of bytes to read
+ from the key file. See
+ <citerefentry project='die-net'><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 key file
+ size is then given by the key size.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>key-slot=</option></term>
+
+ <listitem><para>Specifies the key slot to compare the
+ passphrase or key against. If the key slot does not match the
+ given passphrase or key, but another would, the setup of the
+ device will fail regardless. This option implies
+ <option>luks</option>. See
+ <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+ for possible values. The default is to try all key slots in
+ sequential order.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>luks</option></term>
+
+ <listitem><para>Force LUKS mode. When this mode is used, the
+ following options are ignored since they are provided by the
+ LUKS header on the device: <option>cipher=</option>,
+ <option>hash=</option>,
+ <option>size=</option>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>_netdev</option></term>
+
+ <listitem><para>Marks this cryptsetup device as requiring network. It will be
+ started after the network is available, similarly to
+ <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ units marked with <option>_netdev</option>. The service unit to set up this device
+ will be ordered between <filename>remote-fs-pre.target</filename> and
+ <filename>remote-cryptsetup.target</filename>, instead of
+ <filename>cryptsetup-pre.target</filename> and
+ <filename>cryptsetup.target</filename>.</para>
+
+ <para>Hint: if this device is used for a mount point that is specified in
+ <citerefentry project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ the <option>_netdev</option> option should also be used for the mount
+ point. Otherwise, a dependency loop might be created where the mount point
+ will be pulled in by <filename>local-fs.target</filename>, while the
+ service to configure the network is usually only started <emphasis>after</emphasis>
+ the local file system has been mounted.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>noauto</option></term>
+
+ <listitem><para>This device will not be added to <filename>cryptsetup.target</filename>.
+ This means that it will not be automatically unlocked on boot, unless something else pulls
+ it in. In particular, if the device is used for a mount point, it'll be unlocked
+ automatically during boot, unless the mount point itself is also disabled with
+ <option>noauto</option>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>nofail</option></term>
+
+ <listitem><para>This device will not be a hard dependency of
+ <filename>cryptsetup.target</filename>. It'll be still pulled in and started, but the system
+ will not wait for the device to show up and be unlocked, and boot will not fail if this is
+ unsuccessful. Note that other units that depend on the unlocked device may still fail. In
+ particular, if the device is used for a mount point, the mount point itself is also needs to
+ have <option>noauto</option> option, or the boot will fail if the device is not unlocked
+ successfully.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>offset=</option></term>
+
+ <listitem><para>Start offset in the backend device, in 512-byte sectors. This
+ option is only relevant for plain devices.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>plain</option></term>
+
+ <listitem><para>Force plain encryption mode.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>read-only</option></term><term><option>readonly</option></term>
+
+ <listitem><para>Set up the encrypted block device in read-only
+ mode.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>same-cpu-crypt</option></term>
+
+ <listitem><para>Perform encryption using the same cpu that IO was submitted on. The default is to use
+ an unbound workqueue so that encryption work is automatically balanced between available CPUs.</para>
+ <para>This requires kernel 4.0 or newer.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>submit-from-crypt-cpus</option></term>
+
+ <listitem><para>Disable offloading writes to a separate thread after encryption. There are some
+ situations where offloading write bios from the encryption threads to a single thread degrades
+ performance significantly. The default is to offload write bios to the same thread because it benefits
+ CFQ to have writes submitted using the same context.</para>
+ <para>This requires kernel 4.0 or newer.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>skip=</option></term>
+
+ <listitem><para>How many 512-byte sectors of the encrypted data to skip at the
+ beginning. This is different from the <option>offset=</option> option with respect
+ to the sector numbers used in initialization vector (IV) calculation. Using
+ <option>offset=</option> will shift the IV calculation by the same negative
+ amount. Hence, if <option>offset=<replaceable>n</replaceable></option> is given,
+ sector <replaceable>n</replaceable> will get a sector number of 0 for the IV
+ calculation. Using <option>skip=</option> causes sector
+ <replaceable>n</replaceable> to also be the first sector of the mapped device, but
+ with its number for IV generation being <replaceable>n</replaceable>.</para>
+
+ <para>This option is only relevant for plain devices.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>size=</option></term>
+
+ <listitem><para>Specifies the key size in bits. See
+ <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+ for possible values and the default value of this
+ option.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>sector-size=</option></term>
+
+ <listitem><para>Specifies the sector size in bytes. See
+ <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+ for possible values and the default value of this
+ option.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>swap</option></term>
+
+ <listitem><para>The encrypted block device will be used as a
+ swap device, and will be formatted accordingly after setting
+ up the encrypted block device, with
+ <citerefentry project='man-pages'><refentrytitle>mkswap</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
+ This option implies <option>plain</option>.</para>
+
+ <para>WARNING: Using the <option>swap</option> 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><option>tcrypt</option></term>
+
+ <listitem><para>Use TrueCrypt encryption mode. When this mode
+ is used, the following options are ignored since they are
+ provided by the TrueCrypt header on the device or do not
+ apply:
+ <option>cipher=</option>,
+ <option>hash=</option>,
+ <option>keyfile-offset=</option>,
+ <option>keyfile-size=</option>,
+ <option>size=</option>.</para>
+
+ <para>When this mode is used, the passphrase is read from the
+ key file given in the third field. Only the first line of this
+ file is read, excluding the new line character.</para>
+
+ <para>Note that the TrueCrypt format uses both passphrase and
+ key files to derive a password for the volume. Therefore, the
+ passphrase and all key files need to be provided. Use
+ <option>tcrypt-keyfile=</option> to provide the absolute path
+ to all key files. When using an empty passphrase in
+ combination with one or more key files, use
+ <literal>/dev/null</literal> as the password file in the third
+ field.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>tcrypt-hidden</option></term>
+
+ <listitem><para>Use the hidden TrueCrypt volume. This option
+ implies <option>tcrypt</option>.</para>
+
+ <para>This will map the hidden volume that is inside of the
+ volume provided in the second field. Please note that there is
+ no protection for the hidden volume if the outer volume is
+ mounted instead. See
+ <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+ for more information on this limitation.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>tcrypt-keyfile=</option></term>
+
+ <listitem><para>Specifies the absolute path to a key file to
+ use for a TrueCrypt volume. This implies
+ <option>tcrypt</option> and can be used more than once to
+ provide several key files.</para>
+
+ <para>See the entry for <option>tcrypt</option> on the
+ behavior of the passphrase and key files when using TrueCrypt
+ encryption mode.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>tcrypt-system</option></term>
+
+ <listitem><para>Use TrueCrypt in system encryption mode. This
+ option implies <option>tcrypt</option>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>tcrypt-veracrypt</option></term>
+
+ <listitem><para>Check for a VeraCrypt volume. VeraCrypt is a fork of
+ TrueCrypt that is mostly compatible, but uses different, stronger key
+ derivation algorithms that cannot be detected without this flag.
+ Enabling this option could substantially slow down unlocking, because
+ VeraCrypt's key derivation takes much longer than TrueCrypt's. This
+ option implies <option>tcrypt</option>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>timeout=</option></term>
+
+ <listitem><para>Specifies 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><option>tmp</option></term>
+
+ <listitem><para>The encrypted block device will be prepared
+ for using it as <filename>/tmp</filename>; it will be
+ formatted using
+ <citerefentry project='man-pages'><refentrytitle>mke2fs</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
+ This option implies <option>plain</option>.</para>
+
+ <para>WARNING: Using the <option>tmp</option> 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><option>tries=</option></term>
+
+ <listitem><para>Specifies the maximum number of times the user
+ is queried for a password. The default is 3. If set to 0, the
+ user is queried for a password indefinitely.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>verify</option></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><option>x-systemd.device-timeout=</option></term>
+
+ <listitem><para>Specifies how long systemd should wait for a device to show up
+ before giving up on the entry. The argument is a time in seconds or explicitly
+ specified units of
+ <literal>s</literal>,
+ <literal>min</literal>,
+ <literal>h</literal>,
+ <literal>ms</literal>.
+ </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 four encrypted block devices. One using LUKS for
+ normal storage, another one for usage as a swap device and two
+ TrueCrypt volumes.</para>
+
+ <programlisting>luks UUID=2505567a-9e27-4efe-a4d5-15ad146c258b
+swap /dev/sda7 /dev/urandom swap
truecrypt /dev/sda2 /etc/container_password tcrypt
-hidden /mnt/tc_hidden /dev/null tcrypt-hidden,tcrypt-keyfile=/etc/keyfile</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 project='man-pages'><refentrytitle>mkswap</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
- <citerefentry project='man-pages'><refentrytitle>mke2fs</refentrytitle><manvolnum>8</manvolnum></citerefentry>
- </para>
- </refsect1>
+hidden /mnt/tc_hidden /dev/null tcrypt-hidden,tcrypt-keyfile=/etc/keyfile</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 project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+ <citerefentry project='man-pages'><refentrytitle>mkswap</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+ <citerefentry project='man-pages'><refentrytitle>mke2fs</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+ </para>
+ </refsect1>
</refentry>
projects / thirdparty / systemd.git / blobdiff