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Committer: Teddy Hogeborn
Date: 2008-08-31 13:55:04 UTC
Revision ID: teddy@fukt.bsnet.se-20080831135504-2ka1cccglsghslxy

* plugin-runner.xml (/refentry/refentryinfo/copyright): Split
                                                        copyright
                                                        holders.
* plugins.d/password-request.xml (/refentry/refentryinfo/copyright):
                                 Split copyright holders.

files added:
.bzrignore

COPYING

initramfs-tools-hook

initramfs-tools-hook-conf

initramfs-tools-script

mandos-keygen

mandos-keygen.xml

mandos-options.xml

overview.xml

plugins.d/usplash

files removed:
network-protocol.txt

files renamed:
mandos-client.c => plugin-runner.c

mandos-client.xml => plugin-runner.xml

files modified:
Makefile

TODO

clients.conf

mandos

mandos-clients.conf.xml

mandos.conf

mandos.conf.xml

mandos.xml

plugins.d/password-prompt.c

plugins.d/password-prompt.xml

plugins.d/password-request.c

plugins.d/password-request.xml

Show diffs side-by-side

added added

removed removed

mandos.xml

<?xml version='1.0' encoding='UTF-8'?>

<?xml-stylesheet type="text/xsl"

href="http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl"?>

<?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 VERSION "1.0">

<!ENTITY COMMANDNAME "mandos">

<!ENTITY TIMESTAMP "2008-08-31">

<title>&COMMANDNAME;</title>

<productname>&COMMANDNAME;</productname>

<title>Mandos Manual</title>

<productname>Mandos</productname>

<productnumber>&VERSION;</productnumber>

<date>&TIMESTAMP;</date>

<firstname>Björn</firstname>

</authorgroup>

<holder>Teddy Hogeborn & Björn Påhlsson</holder>

<holder>Teddy Hogeborn</holder>

<holder>Björn Påhlsson</holder>

</copyright>

<para>

<refname><command>&COMMANDNAME;</command></refname>

Sends encrypted passwords to authenticated mandos clients

Gives encrypted passwords to authenticated Mandos clients

</refpurpose>

</refnamediv>

<command>&COMMANDNAME;</command>

<arg choice='opt'>--interface<arg choice='plain'>IF</arg></arg>

<arg choice='opt'>--address<arg choice='plain'>ADDRESS</arg></arg>

<arg choice='opt'>--priority<arg choice='plain'>PRIORITY</arg></arg>

<arg choice='opt'>--servicename<arg choice='plain'>NAME</arg></arg>

<arg choice='opt'>--configdir<arg choice='plain'>DIRECTORY</arg></arg>

<arg choice='opt'>--debug</arg>

</cmdsynopsis>

<command>&COMMANDNAME;</command>

</cmdsynopsis>

<command>&COMMANDNAME;</command>

<arg choice='plain'>--version</arg>

</cmdsynopsis>

<command>&COMMANDNAME;</command>

<arg choice='plain'>--check</arg>

</cmdsynopsis>

<group>

<arg choice="plain"><option>--interface

<arg choice="plain"><option>-i

</group>

<sbr/>

<group>

<arg choice="plain"><option>--address

<replaceable>ADDRESS</replaceable></option></arg>

<arg choice="plain"><option>-a

<replaceable>ADDRESS</replaceable></option></arg>

</group>

<sbr/>

<group>

<arg choice="plain"><option>--port

<arg choice="plain"><option>-p

</group>

<sbr/>

<arg><option>--priority

<replaceable>PRIORITY</replaceable></option></arg>

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<sbr/>

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<arg><option>--servicename

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<sbr/>

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<arg><option>--configdir

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<replaceable>DIRECTORY</replaceable></option></arg>

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<sbr/>

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<arg><option>--debug</option></arg>

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</cmdsynopsis>

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<command>&COMMANDNAME;</command>

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</group>

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</cmdsynopsis>

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<command>&COMMANDNAME;</command>

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<arg choice="plain"><option>--version</option></arg>

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</cmdsynopsis>

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<command>&COMMANDNAME;</command>

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<arg choice="plain"><option>--check</option></arg>

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</cmdsynopsis>

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</refsynopsisdiv>

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<title>DESCRIPTION</title>

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<para>

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<command>&COMMANDNAME;</command> is a server daemon that handels

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incomming passwords request for passwords. Mandos use avahi to

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announce the service, and through gnutls authenticates

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clients. Any authenticated client is then given its encrypted

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password.

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</para>

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<para>

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show a help message and exit

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</para>

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</listitem>

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</varlistentry>

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<term><literal>-i</literal>, <literal>--interface <replaceable>

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IF</replaceable></literal></term>

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<para>

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Bind to interface IF

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</para>

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</listitem>

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</varlistentry>

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<term><literal>-a</literal>, <literal>--address <replaceable>

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ADDRESS</replaceable></literal></term>

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<para>

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Address to listen for requests on

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</para>

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</listitem>

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</varlistentry>

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PORT</replaceable></literal></term>

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<para>

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Port number to receive requests on

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</para>

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</listitem>

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</varlistentry>

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<term><literal>--check</literal></term>

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<para>

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Run self-test on the server

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</para>

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</listitem>

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</varlistentry>

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<term><literal>--debug</literal></term>

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<para>

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Debug mode

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</para>

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</listitem>

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</varlistentry>

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<term><literal>--priority <replaceable>

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PRIORITY</replaceable></literal></term>

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<para>

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GnuTLS priority string. See <citerefentry>

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<refentrytitle>gnutls_priority_init</refentrytitle>

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</para>

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</listitem>

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</varlistentry>

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<term><literal>--servicename <replaceable>NAME</replaceable>

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</literal></term>

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<para>

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Zeroconf service name

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</para>

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</listitem>

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</varlistentry>

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<term><literal>--configdir <replaceable>DIR</replaceable>

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</literal></term>

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<para>

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Directory to search for configuration files

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</para>

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</listitem>

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</varlistentry>

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<term><literal>--version</literal></term>

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<para>

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Prints the program version

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</para>

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</listitem>

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</varlistentry>

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<command>&COMMANDNAME;</command> is a server daemon which

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handles incoming request for passwords for a pre-defined list of

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client host computers. The Mandos server uses Zeroconf to

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announce itself on the local network, and uses TLS to

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communicate securely with and to authenticate the clients. The

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Mandos server uses IPv6 to allow Mandos clients to use IPv6

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link-local addresses, since the clients will probably not have

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any other addresses configured (see <xref linkend="overview"/>).

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Any authenticated client is then given the stored pre-encrypted

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password for that specific client.

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</para>

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</refsect1>

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<title>PURPOSE</title>

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<para>

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The purpose of this is to enable <emphasis>remote and unattended

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rebooting</emphasis> of client host computer with an

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<emphasis>encrypted root file system</emphasis>. See <xref

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linkend="overview"/> for details.

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</para>

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</refsect1>

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<title>OPTIONS</title>

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<para>

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Show a help message and exit

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</para>

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</listitem>

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</varlistentry>

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<term><option>--interface</option>

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<xi:include href="mandos-options.xml" xpointer="interface"/>

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</listitem>

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</varlistentry>

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<term><option>--address

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<replaceable>ADDRESS</replaceable></option></term>

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<term><option>-a

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<replaceable>ADDRESS</replaceable></option></term>

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<xi:include href="mandos-options.xml" xpointer="address"/>

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</listitem>

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</varlistentry>

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<term><option>--port

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<term><option>-p

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<xi:include href="mandos-options.xml" xpointer="port"/>

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</listitem>

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</varlistentry>

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<term><option>--check</option></term>

201

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<para>

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Run the server’s self-tests. This includes any unit

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tests, etc.

205

</para>

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</listitem>

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</varlistentry>

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<term><option>--debug</option></term>

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<xi:include href="mandos-options.xml" xpointer="debug"/>

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</listitem>

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</varlistentry>

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<term><option>--priority <replaceable>

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PRIORITY</replaceable></option></term>

219

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<xi:include href="mandos-options.xml" xpointer="priority"/>

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</listitem>

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</varlistentry>

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<term><option>--servicename

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<xi:include href="mandos-options.xml"

229

xpointer="servicename"/>

230

</listitem>

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</varlistentry>

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<term><option>--configdir

235

<replaceable>DIRECTORY</replaceable></option></term>

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<para>

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Directory to search for configuration files. Default is

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<quote><literal>/etc/mandos</literal></quote>. See

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<citerefentry><refentrytitle>mandos.conf</refentrytitle>

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<refentrytitle>mandos-clients.conf</refentrytitle>

243

<manvolnum>5</manvolnum></citerefentry>.

244

</para>

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</listitem>

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</varlistentry>

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<term><option>--version</option></term>

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<para>

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Prints the program version and exit.

253

</para>

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</listitem>

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</varlistentry>

256

</variablelist>

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</refsect1>

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<title>OVERVIEW</title>

261

<xi:include href="overview.xml"/>

262

<para>

263

This program is the server part. It is a normal server program

264

and will run in a normal system environment, not in an initial

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RAM disk environment.

266

</para>

267

</refsect1>

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<title>NETWORK PROTOCOL</title>

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<para>

272

The Mandos server announces itself as a Zeroconf service of type

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<quote><literal>_mandos._tcp</literal></quote>. The Mandos

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client connects to the announced address and port, and sends a

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line of text where the first whitespace-separated field is the

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protocol version, which currently is

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<quote><literal>1</literal></quote>. The client and server then

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start a TLS protocol handshake with a slight quirk: the Mandos

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server program acts as a TLS <quote>client</quote> while the

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connecting Mandos client acts as a TLS <quote>server</quote>.

281

The Mandos client must supply an OpenPGP certificate, and the

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fingerprint of this certificate is used by the Mandos server to

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look up (in a list read from <filename>clients.conf</filename>

284

at start time) which binary blob to give the client. No other

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authentication or authorization is done by the server.

286

</para>

287

<table>

288

<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>

289

<row>

290

<entry>Mandos Client</entry>

291

<entry>Direction</entry>

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<entry>Mandos Server</entry>

293

</row>

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</thead><tbody>

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<row>

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<entry>Connect</entry>

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</row>

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<row>

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</row>

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<row>

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<entry>TLS handshake <emphasis>as TLS <quote>server</quote>

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</emphasis></entry>

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<entry>TLS handshake <emphasis>as TLS <quote>client</quote>

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</emphasis></entry>

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</row>

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<row>

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<entry>OpenPGP public key (part of TLS handshake)</entry>

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</row>

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<row>

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<entry>Binary blob (client will assume OpenPGP data)</entry>

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</row>

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<row>

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<entry>Close</entry>

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</row>

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</tbody></tgroup></table>

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</refsect1>

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<title>CHECKING</title>

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<para>

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The server will, by default, continually check that the clients

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are still up. If a client has not been confirmed as being up

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for some time, the client is assumed to be compromised and is no

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longer eligible to receive the encrypted password. The timeout,

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checker program, and interval between checks can be configured

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both globally and per client; see <citerefentry>

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<refentrytitle>mandos-clients.conf</refentrytitle>

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<manvolnum>5</manvolnum></citerefentry>.

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</para>

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</refsect1>

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<title>LOGGING</title>

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<para>

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The server will send log message with various severity levels to

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<filename>/dev/log</filename>. With the

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<option>--debug</option> option, it will log even more messages,

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and also show them on the console.

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</para>

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</refsect1>

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<title>EXIT STATUS</title>

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<para>

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The server will exit with a non-zero exit status only when a

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critical error is encountered.

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</para>

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</refsect1>

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<title>ENVIRONMENT</title>

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<para>

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To start the configured checker (see <xref

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linkend="checking"/>), the server uses

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<filename>/bin/sh</filename>, which in turn uses

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<varname>PATH</varname> to search for matching commands if

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an absolute path is not given. See <citerefentry>

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</citerefentry>.

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</para>

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</listitem>

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</varlistentry>

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</variablelist>

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</refsect1>

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<title>FILES</title>

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<para>

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Use the <option>--configdir</option> option to change where

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<command>&COMMANDNAME;</command> looks for its configurations

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files. The default file names are listed here.

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</para>

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<term><filename>/etc/mandos/mandos.conf</filename></term>

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<para>

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Server-global settings. See

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<citerefentry><refentrytitle>mandos.conf</refentrytitle>

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<manvolnum>5</manvolnum></citerefentry> for details.

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</para>

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</listitem>

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</varlistentry>

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<term><filename>/etc/mandos/clients.conf</filename></term>

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<para>

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List of clients and client-specific settings. See

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<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>

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<manvolnum>5</manvolnum></citerefentry> for details.

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</para>

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</listitem>

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</varlistentry>

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<term><filename>/var/run/mandos/mandos.pid</filename></term>

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<para>

411

The file containing the process id of

412

<command>&COMMANDNAME;</command>.

413

</para>

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</listitem>

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</varlistentry>

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<para>

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The Unix domain socket to where local syslog messages are

421

sent.

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</para>

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</listitem>

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</varlistentry>

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<para>

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This is used to start the configured checker command for

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each client. See <citerefentry>

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<refentrytitle>mandos-clients.conf</refentrytitle>

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<manvolnum>5</manvolnum></citerefentry> for details.

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</para>

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</listitem>

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</varlistentry>

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</variablelist>

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</refsect1>

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<para>

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This server might, on especially fatal errors, emit a Python

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backtrace. This could be considered a feature.

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</para>

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<para>

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Currently, if a client is declared <quote>invalid</quote> due to

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having timed out, the server does not record this fact onto

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permanent storage. This has some security implications, see

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<xref linkend="CLIENTS"/>.

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</para>

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<para>

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There is currently no way of querying the server of the current

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status of clients, other than analyzing its <systemitem

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class="service">syslog</systemitem> output.

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</para>

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<para>

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There is no fine-grained control over logging and debug output.

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</para>

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<para>

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Debug mode is conflated with running in the foreground.

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</para>

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<para>

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The console log messages does not show a timestamp.

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</para>

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</refsect1>

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<title>EXAMPLE</title>

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<para>

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Normal invocation needs no options:

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</para>

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<para>

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<userinput>&COMMANDNAME;</userinput>

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</para>

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</informalexample>

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<para>

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Run the server in debug mode, read configuration files from

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the <filename>~/mandos</filename> directory, and use the

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Zeroconf service name <quote>Test</quote> to not collide with

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any other official Mandos server on this host:

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</para>

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<para>

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<userinput>&COMMANDNAME; --debug --configdir ~/mandos --servicename Test</userinput>

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</para>

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</informalexample>

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<para>

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Run the server normally, but only listen to one interface and

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only on the link-local address on that interface:

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</para>

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<para>

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<userinput>&COMMANDNAME; --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>

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</para>

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</informalexample>

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</refsect1>

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<title>SECURITY</title>

507

508

<title>SERVER</title>

509

<para>

510

Running this <command>&COMMANDNAME;</command> server program

511

should not in itself present any security risk to the host

512

computer running it. The program does not need any special

513

privileges to run, and is designed to run as a non-root user.

514

</para>

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</refsect2>

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517

<title>CLIENTS</title>

518

<para>

519

The server only gives out its stored data to clients which

520

does have the OpenPGP key of the stored fingerprint. This is

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guaranteed by the fact that the client sends its OpenPGP

522

public key in the TLS handshake; this ensures it to be

523

genuine. The server computes the fingerprint of the key

524

itself and looks up the fingerprint in its list of

525

clients. The <filename>clients.conf</filename> file (see

526

<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>

527

<manvolnum>5</manvolnum></citerefentry>)

528

<emphasis>must</emphasis> be made non-readable by anyone

529

except the user running the server.

530

</para>

531

<para>

532

As detailed in <xref linkend="checking"/>, the status of all

533

client computers will continually be checked and be assumed

534

compromised if they are gone for too long.

535

</para>

536

<para>

537

If a client is compromised, its downtime should be duly noted

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by the server which would therefore declare the client

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invalid. But if the server was ever restarted, it would

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re-read its client list from its configuration file and again

541

regard all clients therein as valid, and hence eligible to

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receive their passwords. Therefore, be careful when

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restarting servers if it is suspected that a client has, in

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fact, been compromised by parties who may now be running a

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fake Mandos client with the keys from the non-encrypted

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initial RAM image of the client host. What should be done in

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that case (if restarting the server program really is

548

necessary) is to stop the server program, edit the

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configuration file to omit any suspect clients, and restart

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the server program.

551

</para>

552

<para>

553

For more details on client-side security, see

554

<citerefentry><refentrytitle>password-request</refentrytitle>

555

<manvolnum>8mandos</manvolnum></citerefentry>.

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</para>

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</refsect2>

558

</refsect1>

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<para>

563

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<refentrytitle>mandos-clients.conf</refentrytitle>

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<refentrytitle>mandos.conf</refentrytitle>

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<refentrytitle>password-request</refentrytitle>

569

<manvolnum>8mandos</manvolnum></citerefentry>, <citerefentry>

570

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</citerefentry>

572

</para>

573

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575

<term>

576

<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>

577

</term>

578

579

<para>

580

Zeroconf is the network protocol standard used by clients

581

for finding this Mandos server on the local network.

582

</para>

583

</listitem>

584

</varlistentry>

585

586

<term>

587

<ulink url="http://www.avahi.org/">Avahi</ulink>

588

</term>

589

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<para>

591

Avahi is the library this server calls to implement

592

Zeroconf service announcements.

593

</para>

594

</listitem>

595

</varlistentry>

596

597

<term>

598

<ulink url="http://www.gnu.org/software/gnutls/"

599

>GnuTLS</ulink>

600

</term>

601

602

<para>

603

GnuTLS is the library this server uses to implement TLS for

604

communicating securely with the client, and at the same time

605

confidently get the client’s public OpenPGP key.

606

</para>

607

</listitem>

608

</varlistentry>

609

610

<term>

611

RFC 4291: <citetitle>IP Version 6 Addressing

612

Architecture</citetitle>

613

</term>

614

615

616

617

<term>Section 2.2: <citetitle>Text Representation of

618

Addresses</citetitle></term>

619

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</varlistentry>

621

622

<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6

623

Address</citetitle></term>

624

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</varlistentry>

626

627

<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast

628

Addresses</citetitle></term>

629

630

<para>

631

The clients use IPv6 link-local addresses, which are

632

immediately usable since a link-local addresses is

633

automatically assigned to a network interfaces when it

634

is brought up.

635

</para>

636

</listitem>

637

</varlistentry>

638

</variablelist>

639

</listitem>

640

</varlistentry>

641

642

<term>

643

RFC 4346: <citetitle>The Transport Layer Security (TLS)

644

Protocol Version 1.1</citetitle>

645

</term>

646

647

<para>

648

TLS 1.1 is the protocol implemented by GnuTLS.

649

</para>

650

</listitem>

651

</varlistentry>

652

653

<term>

654

RFC 4880: <citetitle>OpenPGP Message Format</citetitle>

655

</term>

656

657

<para>

658

The data sent to clients is binary encrypted OpenPGP data.

659

</para>

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</listitem>

661

</varlistentry>

662

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<term>

664

RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer

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Security</citetitle>

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</term>

667

668

<para>

669

This is implemented by GnuTLS and used by this server so

670

that OpenPGP keys can be used.

671

</para>

672

</listitem>

673

</varlistentry>

207

674

</variablelist>

208

675

</refsect1>

209

676

</refentry>

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