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| -rw-r--r-- | man/systemd-cryptsetup.xml | 119 |
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diff --git a/man/systemd-cryptsetup.xml b/man/systemd-cryptsetup.xml new file mode 100644 index 0000000..1d3a313 --- /dev/null +++ b/man/systemd-cryptsetup.xml @@ -0,0 +1,119 @@ +<?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>, + <ulink url="https://systemd.io/TPM2_PCR_MEASUREMENTS">TPM2 PCR Measurements Made by systemd</ulink> + </para> + </refsect1> + +</refentry> |