1
<?xml version="1.0" encoding="UTF-8"?>
1
<?xml version='1.0' encoding='UTF-8'?>
2
<?xml-stylesheet type="text/xsl"
3
href="http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl"?>
2
4
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
3
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
5
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
6
<!ENTITY VERSION "1.0">
4
7
<!ENTITY COMMANDNAME "mandos">
5
<!ENTITY TIMESTAMP "2022-04-24">
6
<!ENTITY % common SYSTEM "common.ent">
10
<refentry xmlns:xi="http://www.w3.org/2001/XInclude">
12
<title>Mandos Manual</title>
13
<!-- NWalsh’s docbook scripts use this to generate the footer: -->
14
<productname>Mandos</productname>
15
<productnumber>&version;</productnumber>
16
<date>&TIMESTAMP;</date>
12
<title>&COMMANDNAME;</title>
13
<!-- NWalsh's docbook scripts use this to generate the footer: -->
14
<productname>&COMMANDNAME;</productname>
15
<productnumber>&VERSION;</productnumber>
19
18
<firstname>Björn</firstname>
20
19
<surname>Påhlsson</surname>
22
<email>belorn@recompile.se</email>
21
<email>belorn@fukt.bsnet.se</email>
26
25
<firstname>Teddy</firstname>
27
26
<surname>Hogeborn</surname>
29
<email>teddy@recompile.se</email>
28
<email>teddy@fukt.bsnet.se</email>
46
<holder>Teddy Hogeborn</holder>
47
<holder>Björn Påhlsson</holder>
34
<holder>Teddy Hogeborn & Björn Påhlsson</holder>
49
<xi:include href="legalnotice.xml"/>
38
This manual page is free software: you can redistribute it
39
and/or modify it under the terms of the GNU General Public
40
License as published by the Free Software Foundation,
41
either version 3 of the License, or (at your option) any
46
This manual page is distributed in the hope that it will
47
be useful, but WITHOUT ANY WARRANTY; without even the
48
implied warranty of MERCHANTABILITY or FITNESS FOR A
49
PARTICULAR PURPOSE. See the GNU General Public License
54
You should have received a copy of the GNU General Public
55
License along with this program; If not, see
56
<ulink url="http://www.gnu.org/licenses/"/>.
53
62
<refentrytitle>&COMMANDNAME;</refentrytitle>
54
<manvolnum>8</manvolnum>
63
<manvolnum>8mandos</manvolnum>
58
67
<refname><command>&COMMANDNAME;</command></refname>
60
Gives encrypted passwords to authenticated Mandos clients
69
Sends encrypted passwords to authenticated mandos clients
66
75
<command>&COMMANDNAME;</command>
68
<arg choice="plain"><option>--interface
69
<replaceable>NAME</replaceable></option></arg>
70
<arg choice="plain"><option>-i
71
<replaceable>NAME</replaceable></option></arg>
75
<arg choice="plain"><option>--address
76
<replaceable>ADDRESS</replaceable></option></arg>
77
<arg choice="plain"><option>-a
78
<replaceable>ADDRESS</replaceable></option></arg>
82
<arg choice="plain"><option>--port
83
<replaceable>PORT</replaceable></option></arg>
84
<arg choice="plain"><option>-p
85
<replaceable>PORT</replaceable></option></arg>
88
<arg><option>--priority
89
<replaceable>PRIORITY</replaceable></option></arg>
91
<arg><option>--servicename
92
<replaceable>NAME</replaceable></option></arg>
94
<arg><option>--configdir
95
<replaceable>DIRECTORY</replaceable></option></arg>
97
<arg><option>--debug</option></arg>
99
<arg><option>--debuglevel
100
<replaceable>LEVEL</replaceable></option></arg>
102
<arg><option>--no-dbus</option></arg>
104
<arg><option>--no-ipv6</option></arg>
106
<arg><option>--no-restore</option></arg>
108
<arg><option>--statedir
109
<replaceable>DIRECTORY</replaceable></option></arg>
111
<arg><option>--socket
112
<replaceable>FD</replaceable></option></arg>
114
<arg><option>--foreground</option></arg>
116
<arg><option>--no-zeroconf</option></arg>
119
<command>&COMMANDNAME;</command>
121
<arg choice="plain"><option>--help</option></arg>
122
<arg choice="plain"><option>-h</option></arg>
126
<command>&COMMANDNAME;</command>
127
<arg choice="plain"><option>--version</option></arg>
130
<command>&COMMANDNAME;</command>
131
<arg choice="plain"><option>--check</option></arg>
76
<arg choice='opt' rep='repeat'>OPTION</arg>
135
80
<refsect1 id="description">
136
81
<title>DESCRIPTION</title>
138
<command>&COMMANDNAME;</command> is a server daemon which
139
handles incoming requests for passwords for a pre-defined list
140
of client host computers. For an introduction, see
141
<citerefentry><refentrytitle>intro</refentrytitle>
142
<manvolnum>8mandos</manvolnum></citerefentry>. The Mandos server
143
uses Zeroconf to announce itself on the local network, and uses
144
TLS to communicate securely with and to authenticate the
145
clients. The Mandos server uses IPv6 to allow Mandos clients to
146
use IPv6 link-local addresses, since the clients will probably
147
not have any other addresses configured (see <xref
148
linkend="overview"/>). Any authenticated client is then given
149
the stored pre-encrypted password for that specific client.
153
<refsect1 id="purpose">
154
<title>PURPOSE</title>
156
The purpose of this is to enable <emphasis>remote and unattended
157
rebooting</emphasis> of client host computer with an
158
<emphasis>encrypted root file system</emphasis>. See <xref
159
linkend="overview"/> for details.
163
<refsect1 id="options">
164
<title>OPTIONS</title>
167
<term><option>--help</option></term>
168
<term><option>-h</option></term>
171
Show a help message and exit
177
<term><option>--interface</option>
178
<replaceable>NAME</replaceable></term>
179
<term><option>-i</option>
180
<replaceable>NAME</replaceable></term>
182
<xi:include href="mandos-options.xml" xpointer="interface"/>
187
<term><option>--address
188
<replaceable>ADDRESS</replaceable></option></term>
190
<replaceable>ADDRESS</replaceable></option></term>
192
<xi:include href="mandos-options.xml" xpointer="address"/>
198
<replaceable>PORT</replaceable></option></term>
200
<replaceable>PORT</replaceable></option></term>
202
<xi:include href="mandos-options.xml" xpointer="port"/>
207
<term><option>--check</option></term>
210
Run the server’s self-tests. This includes any unit
217
<term><option>--debug</option></term>
219
<xi:include href="mandos-options.xml" xpointer="debug"/>
224
<term><option>--debuglevel
225
<replaceable>LEVEL</replaceable></option></term>
228
Set the debugging log level.
229
<replaceable>LEVEL</replaceable> is a string, one of
230
<quote><literal>CRITICAL</literal></quote>,
231
<quote><literal>ERROR</literal></quote>,
232
<quote><literal>WARNING</literal></quote>,
233
<quote><literal>INFO</literal></quote>, or
234
<quote><literal>DEBUG</literal></quote>, in order of
235
increasing verbosity. The default level is
236
<quote><literal>WARNING</literal></quote>.
242
<term><option>--priority <replaceable>
243
PRIORITY</replaceable></option></term>
245
<xi:include href="mandos-options.xml" xpointer="priority"/>
250
<term><option>--servicename
251
<replaceable>NAME</replaceable></option></term>
253
<xi:include href="mandos-options.xml"
254
xpointer="servicename"/>
259
<term><option>--configdir
260
<replaceable>DIRECTORY</replaceable></option></term>
263
Directory to search for configuration files. Default is
264
<quote><literal>/etc/mandos</literal></quote>. See
265
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
266
<manvolnum>5</manvolnum></citerefentry> and <citerefentry>
267
<refentrytitle>mandos-clients.conf</refentrytitle>
268
<manvolnum>5</manvolnum></citerefentry>.
274
<term><option>--version</option></term>
277
Prints the program version and exit.
283
<term><option>--no-dbus</option></term>
285
<xi:include href="mandos-options.xml" xpointer="dbus"/>
287
See also <xref linkend="dbus_interface"/>.
293
<term><option>--no-ipv6</option></term>
295
<xi:include href="mandos-options.xml" xpointer="ipv6"/>
300
<term><option>--no-restore</option></term>
302
<xi:include href="mandos-options.xml" xpointer="restore"/>
304
See also <xref linkend="persistent_state"/>.
310
<term><option>--statedir
311
<replaceable>DIRECTORY</replaceable></option></term>
313
<xi:include href="mandos-options.xml" xpointer="statedir"/>
318
<term><option>--socket
319
<replaceable>FD</replaceable></option></term>
321
<xi:include href="mandos-options.xml" xpointer="socket"/>
326
<term><option>--foreground</option></term>
328
<xi:include href="mandos-options.xml"
329
xpointer="foreground"/>
334
<term><option>--no-zeroconf</option></term>
336
<xi:include href="mandos-options.xml" xpointer="zeroconf"/>
343
<refsect1 id="overview">
344
<title>OVERVIEW</title>
345
<xi:include href="overview.xml"/>
347
This program is the server part. It is a normal server program
348
and will run in a normal system environment, not in an initial
349
<acronym>RAM</acronym> disk environment.
353
<refsect1 id="protocol">
354
<title>NETWORK PROTOCOL</title>
356
The Mandos server announces itself as a Zeroconf service of type
357
<quote><literal>_mandos._tcp</literal></quote>. The Mandos
358
client connects to the announced address and port, and sends a
359
line of text where the first whitespace-separated field is the
360
protocol version, which currently is
361
<quote><literal>1</literal></quote>. The client and server then
362
start a TLS protocol handshake with a slight quirk: the Mandos
363
server program acts as a TLS <quote>client</quote> while the
364
connecting Mandos client acts as a TLS <quote>server</quote>.
365
The Mandos client must supply a TLS public key, and the key ID
366
of this public key is used by the Mandos server to look up (in a
367
list read from <filename>clients.conf</filename> at start time)
368
which binary blob to give the client. No other authentication
369
or authorization is done by the server.
372
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
374
<entry>Mandos Client</entry>
375
<entry>Direction</entry>
376
<entry>Mandos Server</entry>
380
<entry>Connect</entry>
381
<entry>-><!-- → --></entry>
384
<entry><quote><literal>1\r\n</literal></quote></entry>
385
<entry>-><!-- → --></entry>
388
<entry>TLS handshake <emphasis>as TLS <quote>server</quote>
390
<entry><-><!-- ⟷ --></entry>
391
<entry>TLS handshake <emphasis>as TLS <quote>client</quote>
395
<entry>Public key (part of TLS handshake)</entry>
396
<entry>-><!-- → --></entry>
400
<entry><-<!-- ← --></entry>
401
<entry>Binary blob (client will assume OpenPGP data)</entry>
405
<entry><-<!-- ← --></entry>
408
</tbody></tgroup></table>
411
<refsect1 id="checking">
412
<title>CHECKING</title>
414
The server will, by default, continually check that the clients
415
are still up. If a client has not been confirmed as being up
416
for some time, the client is assumed to be compromised and is no
417
longer eligible to receive the encrypted password. (Manual
418
intervention is required to re-enable a client.) The timeout,
419
extended timeout, checker program, and interval between checks
420
can be configured both globally and per client; see
421
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
422
<manvolnum>5</manvolnum></citerefentry>.
426
<refsect1 id="approval">
427
<title>APPROVAL</title>
429
The server can be configured to require manual approval for a
430
client before it is sent its secret. The delay to wait for such
431
approval and the default action (approve or deny) can be
432
configured both globally and per client; see <citerefentry>
433
<refentrytitle>mandos-clients.conf</refentrytitle>
434
<manvolnum>5</manvolnum></citerefentry>. By default all clients
435
will be approved immediately without delay.
438
This can be used to deny a client its secret if not manually
439
approved within a specified time. It can also be used to make
440
the server delay before giving a client its secret, allowing
441
optional manual denying of this specific client.
446
<refsect1 id="logging">
447
<title>LOGGING</title>
449
The server will send log message with various severity levels to
450
<filename class="devicefile">/dev/log</filename>. With the
451
<option>--debug</option> option, it will log even more messages,
452
and also show them on the console.
456
<refsect1 id="persistent_state">
457
<title>PERSISTENT STATE</title>
459
Client settings, initially read from
460
<filename>clients.conf</filename>, are persistent across
461
restarts, and run-time changes will override settings in
462
<filename>clients.conf</filename>. However, if a setting is
463
<emphasis>changed</emphasis> (or a client added, or removed) in
464
<filename>clients.conf</filename>, this will take precedence.
468
<refsect1 id="dbus_interface">
469
<title>D-BUS INTERFACE</title>
471
The server will by default provide a D-Bus system bus interface.
472
This interface will only be accessible by the root user or a
473
Mandos-specific user, if such a user exists. For documentation
474
of the D-Bus API, see the file <filename>DBUS-API</filename>.
478
<refsect1 id="exit_status">
479
<title>EXIT STATUS</title>
481
The server will exit with a non-zero exit status only when a
482
critical error is encountered.
486
<refsect1 id="environment">
487
<title>ENVIRONMENT</title>
490
<term><envar>PATH</envar></term>
493
To start the configured checker (see <xref
494
linkend="checking"/>), the server uses
495
<filename>/bin/sh</filename>, which in turn uses
496
<varname>PATH</varname> to search for matching commands if
497
an absolute path is not given. See <citerefentry>
498
<refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum>
506
<refsect1 id="files">
509
Use the <option>--configdir</option> option to change where
510
<command>&COMMANDNAME;</command> looks for its configurations
511
files. The default file names are listed here.
515
<term><filename>/etc/mandos/mandos.conf</filename></term>
518
Server-global settings. See
519
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
520
<manvolnum>5</manvolnum></citerefentry> for details.
525
<term><filename>/etc/mandos/clients.conf</filename></term>
528
List of clients and client-specific settings. See
529
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
530
<manvolnum>5</manvolnum></citerefentry> for details.
535
<term><filename>/run/mandos.pid</filename></term>
538
The file containing the process id of the
539
<command>&COMMANDNAME;</command> process started last.
540
<emphasis >Note:</emphasis> If the <filename
541
class="directory">/run</filename> directory does not
542
exist, <filename>/var/run/mandos.pid</filename> will be
549
class="directory">/var/lib/mandos</filename></term>
552
Directory where persistent state will be saved. Change
553
this with the <option>--statedir</option> option. See
554
also the <option>--no-restore</option> option.
559
<term><filename class="devicefile">/dev/log</filename></term>
562
The Unix domain socket to where local syslog messages are
568
<term><filename>/bin/sh</filename></term>
571
This is used to start the configured checker command for
572
each client. See <citerefentry>
573
<refentrytitle>mandos-clients.conf</refentrytitle>
574
<manvolnum>5</manvolnum></citerefentry> for details.
584
This server might, on especially fatal errors, emit a Python
585
backtrace. This could be considered a feature.
588
There is no fine-grained control over logging and debug output.
590
<xi:include href="bugs.xml"/>
593
<refsect1 id="example">
594
<title>EXAMPLE</title>
597
Normal invocation needs no options:
600
<userinput>&COMMANDNAME;</userinput>
605
Run the server in debug mode, read configuration files from
606
the <filename class="directory">~/mandos</filename> directory,
607
and use the Zeroconf service name <quote>Test</quote> to not
608
collide with any other official Mandos server on this host:
612
<!-- do not wrap this line -->
613
<userinput>&COMMANDNAME; --debug --configdir ~/mandos --servicename Test</userinput>
619
Run the server normally, but only listen to one interface and
620
only on the link-local address on that interface:
624
<!-- do not wrap this line -->
625
<userinput>&COMMANDNAME; --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>
631
<refsect1 id="security">
632
<title>SECURITY</title>
633
<refsect2 id="server">
634
<title>SERVER</title>
636
Running this <command>&COMMANDNAME;</command> server program
637
should not in itself present any security risk to the host
638
computer running it. The program switches to a non-root user
642
<refsect2 id="clients">
643
<title>CLIENTS</title>
645
The server only gives out its stored data to clients which
646
does have the correct key ID of the stored key ID. This is
647
guaranteed by the fact that the client sends its public key in
648
the TLS handshake; this ensures it to be genuine. The server
649
computes the key ID of the key itself and looks up the key ID
650
in its list of clients. The <filename>clients.conf</filename>
652
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
653
<manvolnum>5</manvolnum></citerefentry>)
654
<emphasis>must</emphasis> be made non-readable by anyone
655
except the user starting the server (usually root).
658
As detailed in <xref linkend="checking"/>, the status of all
659
client computers will continually be checked and be assumed
660
compromised if they are gone for too long.
663
For more details on client-side security, see
664
<citerefentry><refentrytitle>mandos-client</refentrytitle>
665
<manvolnum>8mandos</manvolnum></citerefentry>.
670
<refsect1 id="see_also">
671
<title>SEE ALSO</title>
673
<citerefentry><refentrytitle>intro</refentrytitle>
674
<manvolnum>8mandos</manvolnum></citerefentry>,
675
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
676
<manvolnum>5</manvolnum></citerefentry>,
677
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
678
<manvolnum>5</manvolnum></citerefentry>,
679
<citerefentry><refentrytitle>mandos-client</refentrytitle>
680
<manvolnum>8mandos</manvolnum></citerefentry>,
681
<citerefentry><refentrytitle>sh</refentrytitle>
682
<manvolnum>1</manvolnum></citerefentry>
687
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
691
Zeroconf is the network protocol standard used by clients
692
for finding this Mandos server on the local network.
698
<ulink url="https://www.avahi.org/">Avahi</ulink>
702
Avahi is the library this server calls to implement
703
Zeroconf service announcements.
709
<ulink url="https://gnutls.org/">GnuTLS</ulink>
713
GnuTLS is the library this server uses to implement TLS for
714
communicating securely with the client, and at the same time
715
confidently get the client’s public key.
721
RFC 4291: <citetitle>IP Version 6 Addressing
722
Architecture</citetitle>
727
<term>Section 2.2: <citetitle>Text Representation of
728
Addresses</citetitle></term>
729
<listitem><para/></listitem>
732
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
733
Address</citetitle></term>
734
<listitem><para/></listitem>
737
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
738
Addresses</citetitle></term>
741
The clients use IPv6 link-local addresses, which are
742
immediately usable since a link-local address is
743
automatically assigned to a network interfaces when it
753
RFC 5246: <citetitle>The Transport Layer Security (TLS)
754
Protocol Version 1.2</citetitle>
758
TLS 1.2 is the protocol implemented by GnuTLS.
764
RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
768
The data sent to clients is binary encrypted OpenPGP data.
774
RFC 7250: <citetitle>Using Raw Public Keys in Transport
775
Layer Security (TLS) and Datagram Transport Layer Security
780
This is implemented by GnuTLS version 3.6.6 and is, if
781
present, used by this server so that raw public keys can be
788
RFC 6091: <citetitle>Using OpenPGP Keys for Transport Layer
789
Security (TLS) Authentication</citetitle>
793
This is implemented by GnuTLS before version 3.6.0 and is,
794
if present, used by this server so that OpenPGP keys can be
83
<command>&COMMANDNAME;</command> is a server daemon that handels
84
incomming passwords request for passwords. Mandos use avahi to
85
announce the service, and through gnutls authenticates
86
clients. Any authenticated client is then given its encrypted
92
<term><literal>-h</literal>, <literal>--help</literal></term>
95
show a help message and exit
101
<term><literal>-i</literal>, <literal>--interface <replaceable>
102
IF</replaceable></literal></term>
111
<term><literal>-a</literal>, <literal>--address <replaceable>
112
ADDRESS</replaceable></literal></term>
115
Address to listen for requests on
121
<term><literal>-p</literal>, <literal>--port <replaceable>
122
PORT</replaceable></literal></term>
125
Port number to receive requests on
131
<term><literal>--check</literal></term>
134
Run self-test on the server
140
<term><literal>--debug</literal></term>
149
<term><literal>--priority <replaceable>
150
PRIORITY</replaceable></literal></term>
153
GnuTLS priority string. See <citerefentry>
154
<refentrytitle>gnutls_priority_init</refentrytitle>
155
<manvolnum>3</manvolnum></citerefentry>
161
<term><literal>--servicename <replaceable>NAME</replaceable>
165
Zeroconf service name
171
<term><literal>--configdir <replaceable>DIR</replaceable>
175
Directory to search for configuration files
802
<!-- Local Variables: -->
803
<!-- time-stamp-start: "<!ENTITY TIMESTAMP [\"']" -->
804
<!-- time-stamp-end: "[\"']>" -->
805
<!-- time-stamp-format: "%:y-%02m-%02d" -->