man: rename systemd-cryptsetup@.service → systemd-cryptsetup

We already had the other name as alias, so this just changes what is the "main"
name. The text is adjusted to describe the command briefly.
This commit is contained in:
Zbigniew Jędrzejewski-Szmek
2023-09-26 17:03:26 +02:00
parent ab68c6fb08
commit 10aeee95d0
2 changed files with 38 additions and 14 deletions
+118
View File
@@ -0,0 +1,118 @@
<?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="systemd-cryptsetup" conditional='HAVE_LIBCRYPTSETUP'>
<refentryinfo>
<title>systemd-cryptsetup</title>
<productname>systemd</productname>
</refentryinfo>
<refmeta>
<refentrytitle>systemd-cryptsetup</refentrytitle>
<manvolnum>8</manvolnum>
</refmeta>
<refnamediv>
<refname>systemd-cryptsetup</refname>
<refname>systemd-cryptsetup@.service</refname>
<!-- <refname>system-systemd\x2dcryptsetup.slice</refname> — this causes meson to go haywire because it
thinks this is a (windows) path. Let's just not create the alias for this name, and only include it
in the synopsis. -->
<refpurpose>Full disk decryption logic</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>systemd-cryptsetup</command>
<arg choice="opt" rep="repeat">OPTIONS</arg>
<arg choice="plain">attach</arg>
<arg choice="plain">VOLUME</arg>
<arg choice="plain">SOURCE-DEVICE</arg>
<arg choice="opt">KEY-FILE</arg>
<arg choice="opt">CONFIG</arg>
</cmdsynopsis>
<cmdsynopsis>
<command>systemd-cryptsetup</command>
<arg choice="opt" rep="repeat">OPTIONS</arg>
<arg choice="plain">detach</arg>
<arg choice="plain">VOLUME</arg>
</cmdsynopsis>
<para><filename>systemd-cryptsetup@.service</filename></para>
<para><filename>system-systemd\x2dcryptsetup.slice</filename></para>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><filename>systemd-cryptsetup</filename> is used to set up (with <command>attach</command>) and tear
down (with <command>detach</command>) access to an encrypted block device. It is primarily used via
<filename>systemd-cryptsetup@.service</filename> during early boot, but may also be be called manually.
The positional arguments <parameter>VOLUME</parameter>, <parameter>SOURCEDEVICE</parameter>,
<parameter>KEY-FILE</parameter>, and <parameter>CRYPTTAB-OPTIONS</parameter> have the same meaning as the
fields in <citerefentry><refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
<para><filename>systemd-cryptsetup@.service</filename> is a service responsible for providing access to
encrypted block devices. It is instantiated for each device that requires decryption.</para>
<para><filename>systemd-cryptsetup@.service</filename> instances are part of the
<filename>system-systemd\x2dcryptsetup.slice</filename> slice, which is destroyed only very late in the
shutdown procedure. This allows the encrypted devices to remain up until filesystems have been unmounted.
</para>
<para><filename>systemd-cryptsetup@.service</filename> will ask
for hard disk passwords via the <ulink
url="https://systemd.io/PASSWORD_AGENTS/">password agent logic</ulink>, in
order to query the user for the password using the right mechanism at boot
and during runtime.</para>
<para>At early boot and when the system manager configuration is reloaded, <filename>/etc/crypttab</filename> is
translated into <filename>systemd-cryptsetup@.service</filename> units by
<citerefentry><refentrytitle>systemd-cryptsetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
<para>In order to unlock a volume a password or binary key is required.
<filename>systemd-cryptsetup@.service</filename> tries to acquire a suitable password or binary key via
the following mechanisms, tried in order:</para>
<orderedlist>
<listitem><para>If a key file is explicitly configured (via the third column in
<filename>/etc/crypttab</filename>), a key read from it is used. If a PKCS#11 token, FIDO2 token or
TPM2 device is configured (using the <varname>pkcs11-uri=</varname>, <varname>fido2-device=</varname>,
<varname>tpm2-device=</varname> options) the key is decrypted before use.</para></listitem>
<listitem><para>If no key file is configured explicitly this way, a key file is automatically loaded
from <filename>/etc/cryptsetup-keys.d/<replaceable>volume</replaceable>.key</filename> and
<filename>/run/cryptsetup-keys.d/<replaceable>volume</replaceable>.key</filename>, if present. Here
too, if a PKCS#11/FIDO2/TPM2 token/device is configured, any key found this way is decrypted before
use.</para></listitem>
<listitem><para>If the <varname>try-empty-password</varname> option is specified then unlocking the
volume with an empty password is attempted.</para></listitem>
<listitem><para>The kernel keyring is then checked for a suitable cached password from previous
attempts.</para></listitem>
<listitem><para>Finally, the user is queried for a password, possibly multiple times, unless
the <varname>headless</varname> option is set.</para></listitem>
</orderedlist>
<para>If no suitable key may be acquired via any of the mechanisms describes above, volume activation fails.</para>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-cryptsetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry><refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-cryptenroll</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>