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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
<!ENTITY COMMANDNAME "password-agent">
<!ENTITY TIMESTAMP "2020-09-16">
<!ENTITY % common SYSTEM "../common.ent">
%common;
]>
<refentry xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>Mandos Manual</title>
<!-- Nwalsh’s docbook scripts use this to generate the footer: -->
<productname>Mandos</productname>
<productnumber>&version;</productnumber>
<date>&TIMESTAMP;</date>
<authorgroup>
<author>
<firstname>Björn</firstname>
<surname>Påhlsson</surname>
<address>
<email>belorn@recompile.se</email>
</address>
</author>
<author>
<firstname>Teddy</firstname>
<surname>Hogeborn</surname>
<address>
<email>teddy@recompile.se</email>
</address>
</author>
</authorgroup>
<copyright>
<year>2019</year>
<year>2020</year>
<holder>Teddy Hogeborn</holder>
<holder>Björn Påhlsson</holder>
</copyright>
<xi:include href="../legalnotice.xml"/>
</refentryinfo>
<refmeta>
<refentrytitle>&COMMANDNAME;</refentrytitle>
<manvolnum>8mandos</manvolnum>
</refmeta>
<refnamediv>
<refname><command>&COMMANDNAME;</command></refname>
<refpurpose>
Run Mandos client as a systemd password agent.
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>&COMMANDNAME;</command>
<arg><option>--agent-directory=<replaceable
>DIRECTORY</replaceable></option></arg>
<sbr/>
<arg><option>--helper-directory=<replaceable
>DIRECTORY</replaceable></option></arg>
<sbr/>
<!-- <arg><option>-\-plugin-helper-dir=<replaceable -->
<!-- >DIRECTORY</replaceable></option></arg> -->
<!-- <sbr/> -->
<arg><option>--user=<replaceable
>USERID</replaceable></option></arg>
<sbr/>
<!-- <arg><option>-\-userid=<replaceable -->
<!-- >ID</replaceable></option></arg> -->
<!-- <sbr/> -->
<arg><option>--group=<replaceable
>GROUPID</replaceable></option></arg>
<sbr/>
<!-- <arg><option>-\-groupid=<replaceable -->
<!-- >ID</replaceable></option></arg> -->
<!-- <sbr/> -->
<arg>--</arg>
<arg>
<replaceable>MANDOS_CLIENT</replaceable>
<group rep="repeat">
<arg choice="plain"><replaceable>OPTIONS</replaceable></arg>
</group>
</arg>
</cmdsynopsis>
<cmdsynopsis>
<command>&COMMANDNAME;</command>
<arg choice="plain"><option>--test</option></arg>
</cmdsynopsis>
<cmdsynopsis>
<command>&COMMANDNAME;</command>
<group choice="req">
<arg choice="plain"><option>--help</option></arg>
<arg choice="plain"><option>-?</option></arg>
</group>
</cmdsynopsis>
<cmdsynopsis>
<command>&COMMANDNAME;</command>
<arg choice="plain"><option>--usage</option></arg>
</cmdsynopsis>
<cmdsynopsis>
<command>&COMMANDNAME;</command>
<group choice="req">
<arg choice="plain"><option>--version</option></arg>
<arg choice="plain"><option>-V</option></arg>
</group>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1 id="description">
<title>DESCRIPTION</title>
<para>
<command>&COMMANDNAME;</command> is a program which is meant to
be a <citerefentry><refentrytitle>systemd</refentrytitle>
<manvolnum>1</manvolnum></citerefentry> <quote>Password
Agent</quote> (See <ulink
url="https://systemd.io/PASSWORD_AGENTS/">Password
Agents</ulink>). The aim of this program is therefore to
acquire and then send a password to some other program which
will use the password to unlock the encrypted root disk.
</para>
<para>
This program is not meant to be invoked directly, but can be in
order to test it.
</para>
</refsect1>
<refsect1 id="purpose">
<title>PURPOSE</title>
<para>
The purpose of this is to enable <emphasis>remote and unattended
rebooting</emphasis> of client host computer with an
<emphasis>encrypted root file system</emphasis>. See <xref
linkend="overview"/> for details.
</para>
</refsect1>
<refsect1>
<title>OPTIONS</title>
<variablelist>
<varlistentry>
<term><option>--agent-directory
<replaceable>DIRECTORY</replaceable></option></term>
<listitem>
<para>
Specify a different agent directory. The default is
<quote><filename class="directory"
>/run/systemd/ask-password</filename ></quote> as per the
<ulink url="https://systemd.io/PASSWORD_AGENTS/">Password
Agents</ulink> specification.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--helper-directory
<replaceable>DIRECTORY</replaceable></option></term>
<listitem>
<para>
Specify a different helper directory. The default is
<quote><filename class="directory"
>/lib/mandos/plugin-helpers</filename
></quote>, which
will exist in the initial <acronym>RAM</acronym> disk
environment. (This will simply be passed to the
<replaceable>MANDOS_CLIENT</replaceable> program via the
<envar>MANDOSPLUGINHELPERDIR</envar> environment variable.
See
<citerefentry><refentrytitle>mandos-client</refentrytitle
><manvolnum>8mandos</manvolnum></citerefentry>.)
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--user
<replaceable>USERID</replaceable></option></term>
<listitem>
<para>
Change real user ID to <replaceable>USERID</replaceable>
when running <replaceable>MANDOS_CLIENT</replaceable>.
The default is 65534. <emphasis>Note:</emphasis> This
must be a number, not a name.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--group
<replaceable>GROUPID</replaceable></option></term>
<listitem>
<para>
Change real group ID to <replaceable>GROUPID</replaceable>
when running <replaceable>MANDOS_CLIENT</replaceable>.
The default is 65534. <emphasis>Note:</emphasis> This
must be a number, not a name.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable>MANDOS_CLIENT</replaceable></term>
<listitem>
<para>
This specifies the file name for
<citerefentry><refentrytitle>mandos-client</refentrytitle
><manvolnum>8mandos</manvolnum></citerefentry>. If the
<quote><option>--</option></quote> option is given, any
following options are passed to the <replaceable
>MANDOS_CLIENT</replaceable> program. The default is
<quote><filename
>/lib/mandos/plugins.d/mandos-client</filename ></quote>
(which is the correct location for the initial
<acronym>RAM</acronym> disk environment) without any
options.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--help</option></term>
<term><option>-?</option></term>
<listitem>
<para>
Gives a help message about options and their meanings.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--test</option></term>
<listitem>
<para>
Ignore normal operation; instead only run self-tests.
Adding the <option>--help</option> option may show more
options possible in combination with
<option>--test</option>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--usage</option></term>
<listitem>
<para>
Gives a short usage message.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--version</option></term>
<term><option>-V</option></term>
<listitem>
<para>
Prints the program version.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id="overview">
<title>OVERVIEW</title>
<xi:include href="../overview.xml"/>
<para>
This program, &COMMANDNAME;, will run on the client side in the
initial <acronym>RAM</acronym> disk environment, and is
responsible for getting a password from the Mandos client
program itself, and to send that password to whatever is
currently asking for a password using the systemd <ulink
url="https://systemd.io/PASSWORD_AGENTS/">Password
Agents</ulink> mechanism.
</para>
<para>To accomplish this, &COMMANDNAME; runs the
<command>mandos-client</command> program (which is the actual
client program communicating with the Mandos server) or,
alternatively, any executable file specified as
<replaceable>MANDOS_CLIENT</replaceable>, and, as soon as a
password is acquired from the
<replaceable>MANDOS_CLIENT</replaceable> program, sends that
password (as per the <ulink
url="https://systemd.io/PASSWORD_AGENTS/">Password Agents</ulink>
specification) to all currently unanswered password questions.
</para>
<para>
This program should be started (normally as a systemd service,
which in turn is normally started by a <citerefentry
><refentrytitle>systemd.path</refentrytitle>
<manvolnum>5</manvolnum></citerefentry> file) as a reaction to
files named <quote><filename>ask.<replaceable>xxxx</replaceable
></filename></quote> appearing in the agent directory
<quote><filename
class="directory">/run/systemd/ask-password</filename></quote>
(or the directory specified by
<option>--agent-directory</option>).
</para>
</refsect1>
<refsect1 id="exit_status">
<title>EXIT STATUS</title>
<para>
Exit status of this program is zero if no errors were
encountered, and otherwise not.
</para>
</refsect1>
<refsect1 id="environment">
<title>ENVIRONMENT</title>
<para>
This program does not use any environment variables itself, it
only passes on its environment to
<replaceable>MANDOS_CLIENT</replaceable>. Also, the
<option>--helper-directory</option> option will affect the
environment variable <envar>MANDOSPLUGINHELPERDIR</envar> for
<replaceable>MANDOS_CLIENT</replaceable>.
</para>
</refsect1>
<refsect1 id="files">
<title>FILES</title>
<para>
<variablelist>
<varlistentry>
<term><filename class="directory"
>/run/systemd/ask-password</filename></term>
<listitem>
<para>
The default directory to watch for password questions as
per the <ulink
url="https://systemd.io/PASSWORD_AGENTS/">Password
Agents</ulink> specification; can be changed by the
<option>--agent-directory</option> option.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename class="directory"
>/lib/mandos/plugin-helpers</filename
></term>
<listitem>
<para>
The helper directory as supplied to
<replaceable>MANDOS_CLIENT</replaceable> via the
<envar>MANDOSPLUGINHELPERDIR</envar> environment
variable; can be changed by the
<option>--helper-directory</option> option.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect1>
<refsect1 id="bugs">
<title>BUGS</title>
<xi:include href="../bugs.xml"/>
</refsect1>
<refsect1 id="examples">
<title>EXAMPLE</title>
<informalexample>
<para>
Normal invocation needs no options:
</para>
<para>
<userinput>&COMMANDNAME;</userinput>
</para>
</informalexample>
<informalexample>
<para>
Run an alternative <replaceable>MANDOS_CLIENT</replaceable>
program::
</para>
<para>
<userinput>&COMMANDNAME; /usr/local/sbin/alternate</userinput>
</para>
</informalexample>
<informalexample>
<para>
Use alternative locations for the helper directory and the
Mandos client, and add extra options suitable for running in
the normal file system:
</para>
<para>
<!-- do not wrap this line -->
<userinput>&COMMANDNAME; --helper-directory=/usr/lib/x86_64-linux-gnu/mandos/plugin-helpers -- /usr/lib/x86_64-linux-gnu/mandos/plugins.d/mandos-client --pubkey=/etc/keys/mandos/pubkey.txt --seckey=/etc/keys/mandos/seckey.txt --tls-pubkey=/etc/keys/mandos/tls-pubkey.pem --tls-privkey=/etc/keys/mandos/tls-privkey.pem</userinput>
</para>
</informalexample>
<informalexample>
<para>
Use the default location for
<citerefentry><refentrytitle>mandos-client</refentrytitle>
<manvolnum>8mandos</manvolnum></citerefentry>, but add many
options to it:
</para>
<para>
<!-- do not wrap this line -->
<userinput>&COMMANDNAME; -- /lib/mandos/plugins.d/mandos-client --pubkey=/etc/mandos/keys/pubkey.txt --seckey=/etc/mandos/keys/seckey.txt --tls-pubkey=/etc/mandos/keys/tls-pubkey.pem --tls-privkey=/etc/mandos/keys/tls-privkey.pem</userinput>
</para>
</informalexample>
<informalexample>
<para>
Only run the self-tests:
</para>
<para>
<userinput>&COMMANDNAME; --test</userinput>
</para>
</informalexample>
</refsect1>
<refsect1 id="security">
<title>SECURITY</title>
<para>
This program will need to run as the root user in order to read
the agent directory and the <quote><filename
>ask.<replaceable>xxxx</replaceable></filename></quote> files
there, and will, when starting the Mandos client program,
require the ability to set the <quote>real</quote> user and
group ids to another user, by default user and group 65534,
which are assumed to be non-privileged. This is done in order
to match the expectations of <citerefentry><refentrytitle
>mandos-client</refentrytitle><manvolnum>8mandos</manvolnum
></citerefentry>, which assumes that its executable file is
owned by the root user and also has the set-user-ID bit set (see
<citerefentry><refentrytitle>execve</refentrytitle><manvolnum
>2</manvolnum></citerefentry>).
</para>
</refsect1>
<refsect1 id="see_also">
<title>SEE ALSO</title>
<para>
<citerefentry><refentrytitle>intro</refentrytitle>
<manvolnum>8mandos</manvolnum></citerefentry>,
<citerefentry><refentrytitle>mandos-client</refentrytitle>
<manvolnum>8mandos</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd</refentrytitle>
<manvolnum>1</manvolnum></citerefentry>,
</para>
<variablelist>
<varlistentry>
<term>
<ulink url="https://systemd.io/PASSWORD_AGENTS/">Password
Agents</ulink>
</term>
<listitem>
<para>
The specification for systemd <quote>Password
Agent</quote> programs, which
<command>&COMMANDNAME;</command> follows.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
</refentry>
<!-- Local Variables: -->
<!-- time-stamp-start: "<!ENTITY TIMESTAMP [\"']" -->
<!-- time-stamp-end: "[\"']>" -->
<!-- time-stamp-format: "%:y-%02m-%02d" -->
<!-- End: -->
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