67
52
<refname><command>&COMMANDNAME;</command></refname>
69
Sends encrypted passwords to authenticated mandos clients
54
Gives encrypted passwords to authenticated Mandos clients
75
60
<command>&COMMANDNAME;</command>
76
<arg choice='opt'>--interface<arg choice='plain'>IF</arg></arg>
77
<arg choice='opt'>--address<arg choice='plain'>ADDRESS</arg></arg>
78
<arg choice='opt'>--port<arg choice='plain'>PORT</arg></arg>
79
<arg choice='opt'>--priority<arg choice='plain'>PRIORITY</arg></arg>
80
<arg choice='opt'>--servicename<arg choice='plain'>NAME</arg></arg>
81
<arg choice='opt'>--configdir<arg choice='plain'>DIRECTORY</arg></arg>
82
<arg choice='opt'>--debug</arg>
85
<command>&COMMANDNAME;</command>
86
<arg choice='plain'>--help</arg>
89
<command>&COMMANDNAME;</command>
90
<arg choice='plain'>--check</arg>
93
<command>&COMMANDNAME;</command>
94
<arg choice='plain'>--version</arg>
62
<arg choice="plain"><option>--interface
63
<replaceable>NAME</replaceable></option></arg>
64
<arg choice="plain"><option>-i
65
<replaceable>NAME</replaceable></option></arg>
69
<arg choice="plain"><option>--address
70
<replaceable>ADDRESS</replaceable></option></arg>
71
<arg choice="plain"><option>-a
72
<replaceable>ADDRESS</replaceable></option></arg>
76
<arg choice="plain"><option>--port
77
<replaceable>PORT</replaceable></option></arg>
78
<arg choice="plain"><option>-p
79
<replaceable>PORT</replaceable></option></arg>
82
<arg><option>--priority
83
<replaceable>PRIORITY</replaceable></option></arg>
85
<arg><option>--servicename
86
<replaceable>NAME</replaceable></option></arg>
88
<arg><option>--configdir
89
<replaceable>DIRECTORY</replaceable></option></arg>
91
<arg><option>--debug</option></arg>
93
<arg><option>--debuglevel
94
<replaceable>LEVEL</replaceable></option></arg>
96
<arg><option>--no-dbus</option></arg>
98
<arg><option>--no-ipv6</option></arg>
100
<arg><option>--no-restore</option></arg>
102
<arg><option>--statedir
103
<replaceable>DIRECTORY</replaceable></option></arg>
105
<arg><option>--socket
106
<replaceable>FD</replaceable></option></arg>
108
<arg><option>--foreground</option></arg>
110
<arg><option>--no-zeroconf</option></arg>
113
<command>&COMMANDNAME;</command>
115
<arg choice="plain"><option>--help</option></arg>
116
<arg choice="plain"><option>-h</option></arg>
120
<command>&COMMANDNAME;</command>
121
<arg choice="plain"><option>--version</option></arg>
124
<command>&COMMANDNAME;</command>
125
<arg choice="plain"><option>--check</option></arg>
98
129
<refsect1 id="description">
99
130
<title>DESCRIPTION</title>
101
<command>&COMMANDNAME;</command> is a server daemon that handels
102
incomming passwords request for passwords. Mandos use avahi to
103
announce the service, and through gnutls authenticates
104
clients. Any authenticated client is then given its encrypted
110
<term><literal>-h</literal>, <literal>--help</literal></term>
113
show a help message and exit
119
<term><literal>-i</literal>, <literal>--interface <replaceable>
120
IF</replaceable></literal></term>
129
<term><literal>-a</literal>, <literal>--address <replaceable>
130
ADDRESS</replaceable></literal></term>
133
Address to listen for requests on
139
<term><literal>-p</literal>, <literal>--port <replaceable>
140
PORT</replaceable></literal></term>
143
Port number to receive requests on
149
<term><literal>--check</literal></term>
152
Run self-test on the server
158
<term><literal>--debug</literal></term>
167
<term><literal>--priority <replaceable>
168
PRIORITY</replaceable></literal></term>
171
GnuTLS priority string. See <citerefentry>
172
<refentrytitle>gnutls_priority_init</refentrytitle>
173
<manvolnum>3</manvolnum></citerefentry>
179
<term><literal>--servicename <replaceable>NAME</replaceable>
183
Zeroconf service name
189
<term><literal>--configdir <replaceable>DIR</replaceable>
193
Directory to search for configuration files
132
<command>&COMMANDNAME;</command> is a server daemon which
133
handles incoming request for passwords for a pre-defined list of
134
client host computers. For an introduction, see
135
<citerefentry><refentrytitle>intro</refentrytitle>
136
<manvolnum>8mandos</manvolnum></citerefentry>. The Mandos server
137
uses Zeroconf to announce itself on the local network, and uses
138
TLS to communicate securely with and to authenticate the
139
clients. The Mandos server uses IPv6 to allow Mandos clients to
140
use IPv6 link-local addresses, since the clients will probably
141
not have any other addresses configured (see <xref
142
linkend="overview"/>). Any authenticated client is then given
143
the stored pre-encrypted password for that specific client.
147
<refsect1 id="purpose">
148
<title>PURPOSE</title>
150
The purpose of this is to enable <emphasis>remote and unattended
151
rebooting</emphasis> of client host computer with an
152
<emphasis>encrypted root file system</emphasis>. See <xref
153
linkend="overview"/> for details.
157
<refsect1 id="options">
158
<title>OPTIONS</title>
161
<term><option>--help</option></term>
162
<term><option>-h</option></term>
165
Show a help message and exit
171
<term><option>--interface</option>
172
<replaceable>NAME</replaceable></term>
173
<term><option>-i</option>
174
<replaceable>NAME</replaceable></term>
176
<xi:include href="mandos-options.xml" xpointer="interface"/>
181
<term><option>--address
182
<replaceable>ADDRESS</replaceable></option></term>
184
<replaceable>ADDRESS</replaceable></option></term>
186
<xi:include href="mandos-options.xml" xpointer="address"/>
192
<replaceable>PORT</replaceable></option></term>
194
<replaceable>PORT</replaceable></option></term>
196
<xi:include href="mandos-options.xml" xpointer="port"/>
201
<term><option>--check</option></term>
204
Run the server’s self-tests. This includes any unit
211
<term><option>--debug</option></term>
213
<xi:include href="mandos-options.xml" xpointer="debug"/>
218
<term><option>--debuglevel
219
<replaceable>LEVEL</replaceable></option></term>
222
Set the debugging log level.
223
<replaceable>LEVEL</replaceable> is a string, one of
224
<quote><literal>CRITICAL</literal></quote>,
225
<quote><literal>ERROR</literal></quote>,
226
<quote><literal>WARNING</literal></quote>,
227
<quote><literal>INFO</literal></quote>, or
228
<quote><literal>DEBUG</literal></quote>, in order of
229
increasing verbosity. The default level is
230
<quote><literal>WARNING</literal></quote>.
236
<term><option>--priority <replaceable>
237
PRIORITY</replaceable></option></term>
239
<xi:include href="mandos-options.xml" xpointer="priority"/>
244
<term><option>--servicename
245
<replaceable>NAME</replaceable></option></term>
247
<xi:include href="mandos-options.xml"
248
xpointer="servicename"/>
253
<term><option>--configdir
254
<replaceable>DIRECTORY</replaceable></option></term>
257
Directory to search for configuration files. Default is
258
<quote><literal>/etc/mandos</literal></quote>. See
259
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
260
<manvolnum>5</manvolnum></citerefentry> and <citerefentry>
261
<refentrytitle>mandos-clients.conf</refentrytitle>
262
<manvolnum>5</manvolnum></citerefentry>.
268
<term><option>--version</option></term>
271
Prints the program version and exit.
277
<term><option>--no-dbus</option></term>
279
<xi:include href="mandos-options.xml" xpointer="dbus"/>
281
See also <xref linkend="dbus_interface"/>.
287
<term><option>--no-ipv6</option></term>
289
<xi:include href="mandos-options.xml" xpointer="ipv6"/>
294
<term><option>--no-restore</option></term>
296
<xi:include href="mandos-options.xml" xpointer="restore"/>
298
See also <xref linkend="persistent_state"/>.
304
<term><option>--statedir
305
<replaceable>DIRECTORY</replaceable></option></term>
307
<xi:include href="mandos-options.xml" xpointer="statedir"/>
312
<term><option>--socket
313
<replaceable>FD</replaceable></option></term>
315
<xi:include href="mandos-options.xml" xpointer="socket"/>
320
<term><option>--foreground</option></term>
322
<xi:include href="mandos-options.xml"
323
xpointer="foreground"/>
328
<term><option>--no-zeroconf</option></term>
330
<xi:include href="mandos-options.xml" xpointer="zeroconf"/>
337
<refsect1 id="overview">
338
<title>OVERVIEW</title>
339
<xi:include href="overview.xml"/>
341
This program is the server part. It is a normal server program
342
and will run in a normal system environment, not in an initial
343
<acronym>RAM</acronym> disk environment.
347
<refsect1 id="protocol">
348
<title>NETWORK PROTOCOL</title>
350
The Mandos server announces itself as a Zeroconf service of type
351
<quote><literal>_mandos._tcp</literal></quote>. The Mandos
352
client connects to the announced address and port, and sends a
353
line of text where the first whitespace-separated field is the
354
protocol version, which currently is
355
<quote><literal>1</literal></quote>. The client and server then
356
start a TLS protocol handshake with a slight quirk: the Mandos
357
server program acts as a TLS <quote>client</quote> while the
358
connecting Mandos client acts as a TLS <quote>server</quote>.
359
The Mandos client must supply an OpenPGP certificate, and the
360
fingerprint of this certificate is used by the Mandos server to
361
look up (in a list read from <filename>clients.conf</filename>
362
at start time) which binary blob to give the client. No other
363
authentication or authorization is done by the server.
366
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
368
<entry>Mandos Client</entry>
369
<entry>Direction</entry>
370
<entry>Mandos Server</entry>
374
<entry>Connect</entry>
375
<entry>-><!-- → --></entry>
378
<entry><quote><literal>1\r\n</literal></quote></entry>
379
<entry>-><!-- → --></entry>
382
<entry>TLS handshake <emphasis>as TLS <quote>server</quote>
384
<entry><-><!-- ⟷ --></entry>
385
<entry>TLS handshake <emphasis>as TLS <quote>client</quote>
389
<entry>OpenPGP public key (part of TLS handshake)</entry>
390
<entry>-><!-- → --></entry>
394
<entry><-<!-- ← --></entry>
395
<entry>Binary blob (client will assume OpenPGP data)</entry>
399
<entry><-<!-- ← --></entry>
402
</tbody></tgroup></table>
405
<refsect1 id="checking">
406
<title>CHECKING</title>
408
The server will, by default, continually check that the clients
409
are still up. If a client has not been confirmed as being up
410
for some time, the client is assumed to be compromised and is no
411
longer eligible to receive the encrypted password. (Manual
412
intervention is required to re-enable a client.) The timeout,
413
extended timeout, checker program, and interval between checks
414
can be configured both globally and per client; see
415
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
416
<manvolnum>5</manvolnum></citerefentry>.
420
<refsect1 id="approval">
421
<title>APPROVAL</title>
423
The server can be configured to require manual approval for a
424
client before it is sent its secret. The delay to wait for such
425
approval and the default action (approve or deny) can be
426
configured both globally and per client; see <citerefentry>
427
<refentrytitle>mandos-clients.conf</refentrytitle>
428
<manvolnum>5</manvolnum></citerefentry>. By default all clients
429
will be approved immediately without delay.
432
This can be used to deny a client its secret if not manually
433
approved within a specified time. It can also be used to make
434
the server delay before giving a client its secret, allowing
435
optional manual denying of this specific client.
440
<refsect1 id="logging">
441
<title>LOGGING</title>
443
The server will send log message with various severity levels to
444
<filename class="devicefile">/dev/log</filename>. With the
445
<option>--debug</option> option, it will log even more messages,
446
and also show them on the console.
450
<refsect1 id="persistent_state">
451
<title>PERSISTENT STATE</title>
453
Client settings, initially read from
454
<filename>clients.conf</filename>, are persistent across
455
restarts, and run-time changes will override settings in
456
<filename>clients.conf</filename>. However, if a setting is
457
<emphasis>changed</emphasis> (or a client added, or removed) in
458
<filename>clients.conf</filename>, this will take precedence.
462
<refsect1 id="dbus_interface">
463
<title>D-BUS INTERFACE</title>
465
The server will by default provide a D-Bus system bus interface.
466
This interface will only be accessible by the root user or a
467
Mandos-specific user, if such a user exists. For documentation
468
of the D-Bus API, see the file <filename>DBUS-API</filename>.
472
<refsect1 id="exit_status">
473
<title>EXIT STATUS</title>
475
The server will exit with a non-zero exit status only when a
476
critical error is encountered.
480
<refsect1 id="environment">
481
<title>ENVIRONMENT</title>
484
<term><envar>PATH</envar></term>
487
To start the configured checker (see <xref
488
linkend="checking"/>), the server uses
489
<filename>/bin/sh</filename>, which in turn uses
490
<varname>PATH</varname> to search for matching commands if
491
an absolute path is not given. See <citerefentry>
492
<refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum>
500
<refsect1 id="files">
503
Use the <option>--configdir</option> option to change where
504
<command>&COMMANDNAME;</command> looks for its configurations
505
files. The default file names are listed here.
509
<term><filename>/etc/mandos/mandos.conf</filename></term>
512
Server-global settings. See
513
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
514
<manvolnum>5</manvolnum></citerefentry> for details.
519
<term><filename>/etc/mandos/clients.conf</filename></term>
522
List of clients and client-specific settings. See
523
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
524
<manvolnum>5</manvolnum></citerefentry> for details.
529
<term><filename>/run/mandos.pid</filename></term>
532
The file containing the process id of the
533
<command>&COMMANDNAME;</command> process started last.
534
<emphasis >Note:</emphasis> If the <filename
535
class="directory">/run</filename> directory does not
536
exist, <filename>/var/run/mandos.pid</filename> will be
542
<term><filename class="devicefile">/dev/log</filename></term>
546
class="directory">/var/lib/mandos</filename></term>
549
Directory where persistent state will be saved. Change
550
this with the <option>--statedir</option> option. See
551
also the <option>--no-restore</option> option.
556
<term><filename>/dev/log</filename></term>
559
The Unix domain socket to where local syslog messages are
565
<term><filename>/bin/sh</filename></term>
568
This is used to start the configured checker command for
569
each client. See <citerefentry>
570
<refentrytitle>mandos-clients.conf</refentrytitle>
571
<manvolnum>5</manvolnum></citerefentry> for details.
581
This server might, on especially fatal errors, emit a Python
582
backtrace. This could be considered a feature.
585
There is no fine-grained control over logging and debug output.
588
This server does not check the expire time of clients’ OpenPGP
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 OpenPGP key of the stored fingerprint. This is
647
guaranteed by the fact that the client sends its OpenPGP
648
public key in the TLS handshake; this ensures it to be
649
genuine. The server computes the fingerprint of the key
650
itself and looks up the fingerprint in its list of
651
clients. The <filename>clients.conf</filename> file (see
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="http://www.avahi.org/">Avahi</ulink>
702
Avahi is the library this server calls to implement
703
Zeroconf service announcements.
709
<ulink url="http://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 OpenPGP 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 addresses 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 6091: <citetitle>Using OpenPGP Keys for Transport Layer
775
Security (TLS) Authentication</citetitle>
779
This is implemented by GnuTLS and used by this server so
780
that OpenPGP keys can be used.
787
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