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<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
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<!ENTITY COMMANDNAME "mandos-client">
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<!ENTITY TIMESTAMP "2011-11-27">
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<!ENTITY % common SYSTEM "../common.ent">
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<!ENTITY VERSION "1.0">
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<!ENTITY COMMANDNAME "password-request">
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<!ENTITY TIMESTAMP "2008-09-03">
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<refentry xmlns:xi="http://www.w3.org/2001/XInclude">
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<title>Mandos Manual</title>
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<!-- NWalsh’s docbook scripts use this to generate the footer: -->
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<!-- Nwalsh’s docbook scripts use this to generate the footer: -->
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<productname>Mandos</productname>
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<productnumber>&version;</productnumber>
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<productnumber>&VERSION;</productnumber>
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<date>&TIMESTAMP;</date>
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<firstname>Björn</firstname>
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<surname>Påhlsson</surname>
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<email>belorn@recompile.se</email>
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<email>belorn@fukt.bsnet.se</email>
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<firstname>Teddy</firstname>
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<surname>Hogeborn</surname>
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<email>teddy@recompile.se</email>
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<email>teddy@fukt.bsnet.se</email>
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<holder>Teddy Hogeborn</holder>
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<holder>Björn Påhlsson</holder>
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<xi:include href="../legalnotice.xml"/>
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<refentrytitle>&COMMANDNAME;</refentrytitle>
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<manvolnum>8mandos</manvolnum>
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<refname><command>&COMMANDNAME;</command></refname>
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Client for <application>Mandos</application>
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<command>&COMMANDNAME;</command>
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<arg choice="plain"><option>--connect
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<replaceable>ADDRESS</replaceable><literal>:</literal
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<replaceable>IPADDR</replaceable><literal>:</literal
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><replaceable>PORT</replaceable></option></arg>
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<arg choice="plain"><option>-c
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<replaceable>ADDRESS</replaceable><literal>:</literal
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<replaceable>IPADDR</replaceable><literal>:</literal
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><replaceable>PORT</replaceable></option></arg>
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<arg choice="plain"><option>--keydir
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<replaceable>DIRECTORY</replaceable></option></arg>
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<arg choice="plain"><option>-d
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<replaceable>DIRECTORY</replaceable></option></arg>
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<arg choice="plain"><option>--interface
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<replaceable>NAME</replaceable></option></arg>
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<arg choice="plain"><option>-i
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</refsynopsisdiv>
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<refsect1 id="description">
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<title>DESCRIPTION</title>
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<command>&COMMANDNAME;</command> is a client program that
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communicates with <citerefentry><refentrytitle
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>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>
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to get a password. In slightly more detail, this client program
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brings up a network interface, uses the interface’s IPv6
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link-local address to get network connectivity, uses Zeroconf to
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find servers on the local network, and communicates with servers
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using TLS with an OpenPGP key to ensure authenticity and
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confidentiality. This client program keeps running, trying all
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servers on the network, until it receives a satisfactory reply
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or a TERM signal. After all servers have been tried, all
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servers are periodically retried. If no servers are found it
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will wait indefinitely for new servers to appear.
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The network interface is selected like this: If an interface is
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specified using the <option>--interface</option> option, that
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interface is used. Otherwise, <command>&COMMANDNAME;</command>
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will choose any interface that is up and running and is not a
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loopback interface, is not a point-to-point interface, is
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capable of broadcasting and does not have the NOARP flag (see
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<citerefentry><refentrytitle>netdevice</refentrytitle>
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<manvolnum>7</manvolnum></citerefentry>). (If the
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<option>--connect</option> option is used, point-to-point
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interfaces and non-broadcast interfaces are accepted.) If no
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acceptable interfaces are found, re-run the check but without
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the <quote>up and running</quote> requirement, and manually take
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the selected interface up (and later take it down on program
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Before a network interface is selected, all <quote>network
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hooks</quote> are run; see <xref linkend="network-hooks"/>.
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to get a password. It uses IPv6 link-local addresses to get
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network connectivity, Zeroconf to find servers, and TLS with an
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OpenPGP key to ensure authenticity and confidentiality. It
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keeps running, trying all servers on the network, until it
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receives a satisfactory reply or a TERM signal is recieved.
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This program is not meant to be run directly; it is really meant
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<term><option>--interface=<replaceable
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>NAME</replaceable></option></term>
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<term><option>--keydir=<replaceable
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>DIRECTORY</replaceable></option></term>
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<replaceable>DIRECTORY</replaceable></option></term>
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Directory to read the OpenPGP key files
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<filename>pubkey.txt</filename> and
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<filename>seckey.txt</filename> from. The default is
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<filename>/conf/conf.d/mandos</filename> (in the initial
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<acronym>RAM</acronym> disk environment).
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<term><option>--interface=
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<replaceable>NAME</replaceable></option></term>
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<replaceable>NAME</replaceable></option></term>
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Network interface that will be brought up and scanned for
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Mandos servers to connect to. The default is the empty
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string, which will automatically choose an appropriate
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Mandos servers to connect to. The default it
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<quote><literal>eth0</literal></quote>.
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If the <option>--connect</option> option is used, this
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specifies the interface to use to connect to the address
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Note that since this program will normally run in the
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initial RAM disk environment, the interface must be an
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interface which exists at that stage. Thus, the interface
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can not be a pseudo-interface such as <quote>br0</quote>
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or <quote>tun0</quote>; such interfaces will not exist
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until much later in the boot process, and can not be used
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by this program, unless created by a <quote>network
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hook</quote> — see <xref linkend="network-hooks"/>.
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<replaceable>NAME</replaceable> can be the string
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<quote><literal>none</literal></quote>; this will not use
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any specific interface, and will not bring up an interface
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on startup. This is not recommended, and only meant for
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<term><option>--delay=<replaceable
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>SECONDS</replaceable></option></term>
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After bringing the network interface up, the program waits
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for the interface to arrive in a <quote>running</quote>
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state before proceeding. During this time, the kernel log
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level will be lowered to reduce clutter on the system
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console, alleviating any other plugins which might be
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using the system console. This option sets the upper
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limit of seconds to wait. The default is 2.5 seconds.
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<term><option>--retry=<replaceable
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>SECONDS</replaceable></option></term>
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All Mandos servers are tried repeatedly until a password
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is received. This value specifies, in seconds, how long
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between each successive try <emphasis>for the same
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server</emphasis>. The default is 10 seconds.
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<term><option>--network-hook-dir=<replaceable
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>DIR</replaceable></option></term>
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Network hook directory. The default directory is
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<quote><filename class="directory"
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>/lib/mandos/network-hooks.d</filename></quote>.
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<term><option>--debug</option></term>
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<filename>/etc/crypttab</filename>, but it would then be
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impossible to enter a password for the encrypted root disk at
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the console, since this program does not read from the console
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at all. This is why a separate plugin runner (<citerefentry>
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<refentrytitle>plugin-runner</refentrytitle>
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<manvolnum>8mandos</manvolnum></citerefentry>) is used to run
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both this program and others in in parallel,
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<emphasis>one</emphasis> of which (<citerefentry>
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at all. This is why a separate plugin (<citerefentry>
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<refentrytitle>password-prompt</refentrytitle>
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<manvolnum>8mandos</manvolnum></citerefentry>) will prompt for
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passwords on the system console.
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<manvolnum>8mandos</manvolnum></citerefentry>) does that, which
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will be run in parallell to this one by the plugin runner.
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<refsect1 id="network-hooks">
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<title>NETWORK HOOKS</title>
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If a network interface like a bridge or tunnel is required to
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find a Mandos server, this requires the interface to be up and
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running before <command>&COMMANDNAME;</command> starts looking
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for Mandos servers. This can be accomplished by creating a
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<quote>network hook</quote> program, and placing it in a special
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Before the network is used (and again before program exit), any
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runnable programs found in the network hook directory are run
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with the argument <quote><literal>start</literal></quote> or
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<quote><literal>stop</literal></quote>. This should bring up or
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down, respectively, any network interface which
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<command>&COMMANDNAME;</command> should use.
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<refsect2 id="hook-requirements">
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<title>REQUIREMENTS</title>
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A network hook must be an executable file, and its name must
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consist entirely of upper and lower case letters, digits,
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underscores, and hyphens.
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A network hook will receive one argument, which can be one of
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<term><literal>start</literal></term>
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This should make the network hook create (if necessary)
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and bring up a network interface.
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<term><literal>stop</literal></term>
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This should make the network hook take down a network
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interface, and delete it if it did not exist previously.
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<term><literal>files</literal></term>
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This should make the network hook print, <emphasis>on
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separate lines</emphasis>, all the files needed for it
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to run. (These files will be copied into the initial
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RAM filesystem.) Intended use is for a network hook
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which is a shell script to print its needed binaries.
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It is not necessary to print any non-executable files
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already in the network hook directory, these will be
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copied implicitly if they otherwise satisfy the name
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The network hook will be provided with a number of environment
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<term><envar>MANDOSNETHOOKDIR</envar></term>
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The network hook directory, specified to
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<command>&COMMANDNAME;</command> by the
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<option>--network-hook-dir</option> option. Note: this
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should <emphasis>always</emphasis> be used by the
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network hook to refer to itself or any files it may
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<term><envar>DEVICE</envar></term>
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The network interface, as specified to
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<command>&COMMANDNAME;</command> by the
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<option>--interface</option> option. If this is not the
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interface a hook will bring up, there is no reason for a
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<term><envar>MODE</envar></term>
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This will be the same as the first argument;
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i.e. <quote><literal>start</literal></quote>,
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<quote><literal>stop</literal></quote>, or
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<quote><literal>files</literal></quote>.
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<term><envar>VERBOSITY</envar></term>
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This will be the <quote><literal>1</literal></quote> if
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the <option>--debug</option> option is passed to
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<command>&COMMANDNAME;</command>, otherwise
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<quote><literal>0</literal></quote>.
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<term><envar>DELAY</envar></term>
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This will be the same as the <option>--delay</option>
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option passed to <command>&COMMANDNAME;</command>.
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A hook may not read from standard input, and should be
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restrictive in printing to standard output or standard error
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unless <varname>VERBOSITY</varname> is
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<quote><literal>1</literal></quote>.
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<refsect1 id="files">
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<title>FILES</title>
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</informalexample>
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<informalexample>
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Run in debug mode, and use a custom key:
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Run in debug mode, and use a custom key directory:
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<!-- do not wrap this line -->
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<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt</userinput>
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<!-- do not wrap this line -->
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<userinput>&COMMANDNAME; --debug --keydir keydir</userinput>
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</informalexample>
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<informalexample>
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Run in debug mode, with a custom key, and do not use Zeroconf
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to locate a server; connect directly to the IPv6 link-local
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Run in debug mode, with a custom key directory, and do not use
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Zeroconf to locate a server; connect directly to the IPv6
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address <quote><systemitem class="ipaddress"
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>fe80::aede:48ff:fe71:f6f2</systemitem></quote>, port 4711,
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using interface eth2:
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>2001:db8:f983:bd0b:30de:ae4a:71f2:f672</systemitem></quote>,
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port 4711, using interface eth2:
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<!-- do not wrap this line -->
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<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt --connect fe80::aede:48ff:fe71:f6f2:4711 --interface eth2</userinput>
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<userinput>&COMMANDNAME; --debug --keydir keydir --connect 2001:db8:f983:bd0b:30de:ae4a:71f2:f672:4711 --interface eth2</userinput>
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</informalexample>
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<refsect1 id="security">
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<title>SECURITY</title>
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The only remaining weak point is that someone with physical
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access to the client hard drive might turn off the client
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computer, read the OpenPGP keys directly from the hard drive,
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and communicate with the server. To safeguard against this, the
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server is supposed to notice the client disappearing and stop
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giving out the encrypted data. Therefore, it is important to
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set the timeout and checker interval values tightly on the
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server. See <citerefentry><refentrytitle
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and communicate with the server. The defense against this is
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that the server is supposed to notice the client disappearing
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and will stop giving out the encrypted data. Therefore, it is
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important to set the timeout and checker interval values tightly
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on the server. See <citerefentry><refentrytitle
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>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>.