68
55
<refname><command>&COMMANDNAME;</command></refname>
70
Sends encrypted passwords to authenticated Mandos clients
57
Gives encrypted passwords to authenticated Mandos clients
76
63
<command>&COMMANDNAME;</command>
77
<arg choice='opt'>--interface<arg choice='plain'>IF</arg></arg>
78
<arg choice='opt'>--address<arg choice='plain'>ADDRESS</arg></arg>
79
<arg choice='opt'>--port<arg choice='plain'>PORT</arg></arg>
80
<arg choice='opt'>--priority<arg choice='plain'>PRIORITY</arg></arg>
81
<arg choice='opt'>--servicename<arg choice='plain'>NAME</arg></arg>
82
<arg choice='opt'>--configdir<arg choice='plain'>DIRECTORY</arg></arg>
83
<arg choice='opt'>--debug</arg>
86
<command>&COMMANDNAME;</command>
87
<arg choice='opt'>-i<arg choice='plain'>IF</arg></arg>
88
<arg choice='opt'>-a<arg choice='plain'>ADDRESS</arg></arg>
89
<arg choice='opt'>-p<arg choice='plain'>PORT</arg></arg>
90
<arg choice='opt'>--priority<arg choice='plain'>PRIORITY</arg></arg>
91
<arg choice='opt'>--servicename<arg choice='plain'>NAME</arg></arg>
92
<arg choice='opt'>--configdir<arg choice='plain'>DIRECTORY</arg></arg>
93
<arg choice='opt'>--debug</arg>
96
<command>&COMMANDNAME;</command>
97
<arg choice='plain'>--help</arg>
100
<command>&COMMANDNAME;</command>
101
<arg choice='plain'>--version</arg>
104
<command>&COMMANDNAME;</command>
105
<arg choice='plain'>--check</arg>
65
<arg choice="plain"><option>--interface
66
<replaceable>NAME</replaceable></option></arg>
67
<arg choice="plain"><option>-i
68
<replaceable>NAME</replaceable></option></arg>
72
<arg choice="plain"><option>--address
73
<replaceable>ADDRESS</replaceable></option></arg>
74
<arg choice="plain"><option>-a
75
<replaceable>ADDRESS</replaceable></option></arg>
79
<arg choice="plain"><option>--port
80
<replaceable>PORT</replaceable></option></arg>
81
<arg choice="plain"><option>-p
82
<replaceable>PORT</replaceable></option></arg>
85
<arg><option>--priority
86
<replaceable>PRIORITY</replaceable></option></arg>
88
<arg><option>--servicename
89
<replaceable>NAME</replaceable></option></arg>
91
<arg><option>--configdir
92
<replaceable>DIRECTORY</replaceable></option></arg>
94
<arg><option>--debug</option></arg>
96
<arg><option>--debuglevel
97
<replaceable>LEVEL</replaceable></option></arg>
99
<arg><option>--no-dbus</option></arg>
101
<arg><option>--no-ipv6</option></arg>
103
<arg><option>--no-restore</option></arg>
105
<arg><option>--statedir
106
<replaceable>DIRECTORY</replaceable></option></arg>
108
<arg><option>--socket
109
<replaceable>FD</replaceable></option></arg>
111
<arg><option>--foreground</option></arg>
113
<arg><option>--no-zeroconf</option></arg>
116
<command>&COMMANDNAME;</command>
118
<arg choice="plain"><option>--help</option></arg>
119
<arg choice="plain"><option>-h</option></arg>
123
<command>&COMMANDNAME;</command>
124
<arg choice="plain"><option>--version</option></arg>
127
<command>&COMMANDNAME;</command>
128
<arg choice="plain"><option>--check</option></arg>
107
130
</refsynopsisdiv>
109
132
<refsect1 id="description">
110
133
<title>DESCRIPTION</title>
112
135
<command>&COMMANDNAME;</command> is a server daemon which
113
136
handles incoming request for passwords for a pre-defined list of
114
client host computers. The Mandos server uses Zeroconf to
115
announce itself on the local network, and uses GnuTLS to
116
communicate securely with and to authenticate the clients.
117
Mandos uses IPv6 link-local addresses, since the clients are
118
assumed to not have any other addresses configured yet. Any
119
authenticated client is then given the pre-encrypted password
120
for that specific client.
137
client host computers. For an introduction, see
138
<citerefentry><refentrytitle>intro</refentrytitle>
139
<manvolnum>8mandos</manvolnum></citerefentry>. The Mandos server
140
uses Zeroconf to announce itself on the local network, and uses
141
TLS to communicate securely with and to authenticate the
142
clients. The Mandos server uses IPv6 to allow Mandos clients to
143
use IPv6 link-local addresses, since the clients will probably
144
not have any other addresses configured (see <xref
145
linkend="overview"/>). Any authenticated client is then given
146
the stored pre-encrypted password for that specific client.
125
150
<refsect1 id="purpose">
126
151
<title>PURPOSE</title>
129
153
The purpose of this is to enable <emphasis>remote and unattended
130
rebooting</emphasis> of any client host computer with an
131
<emphasis>encrypted root file system</emphasis>. The client
132
host computer should start a Mandos client in the initial RAM
133
disk environment, the Mandos client program communicates with
134
this server program to get an encrypted password, which is then
135
decrypted and used to unlock the encrypted root file system.
136
The client host computer can then continue its boot sequence
154
rebooting</emphasis> of client host computer with an
155
<emphasis>encrypted root file system</emphasis>. See <xref
156
linkend="overview"/> for details.
142
160
<refsect1 id="options">
143
161
<title>OPTIONS</title>
147
<term><literal>-h</literal>, <literal>--help</literal></term>
164
<term><option>--help</option></term>
165
<term><option>-h</option></term>
150
168
Show a help message and exit
156
<term><literal>-i</literal>, <literal>--interface <replaceable>
157
IF</replaceable></literal></term>
160
Only announce the server and listen to requests on network
161
interface <replaceable>IF</replaceable>. Default is to
162
use all available interfaces.
168
<term><literal>-a</literal>, <literal>--address <replaceable>
169
ADDRESS</replaceable></literal></term>
172
If this option is used, the server will only listen to a
173
specific address. This must currently be an IPv6 address;
174
an IPv4 address can be specified using the
175
"<literal>::FFFF:192.0.2.3</literal>" syntax. Also, if a
176
link-local address is specified, an interface should be
177
set, since a link-local address is only valid on a single
178
interface. By default, the server will listen to all
185
<term><literal>-p</literal>, <literal>--port <replaceable>
186
PORT</replaceable></literal></term>
189
If this option is used, the server to bind to that
190
port. By default, the server will listen to an arbitrary
191
port given by the operating system.
197
<term><literal>--check</literal></term>
200
Run the server's self-tests. This includes any unit
174
<term><option>--interface</option>
175
<replaceable>NAME</replaceable></term>
176
<term><option>-i</option>
177
<replaceable>NAME</replaceable></term>
179
<xi:include href="mandos-options.xml" xpointer="interface"/>
184
<term><option>--address
185
<replaceable>ADDRESS</replaceable></option></term>
187
<replaceable>ADDRESS</replaceable></option></term>
189
<xi:include href="mandos-options.xml" xpointer="address"/>
195
<replaceable>PORT</replaceable></option></term>
197
<replaceable>PORT</replaceable></option></term>
199
<xi:include href="mandos-options.xml" xpointer="port"/>
204
<term><option>--check</option></term>
207
Run the server’s self-tests. This includes any unit
207
<term><literal>--debug</literal></term>
210
If the server is run in debug mode, it will run in the
211
foreground and print a lot of debugging information. The
212
default is <emphasis>not</emphasis> to run in debug mode.
218
<term><literal>--priority <replaceable>
219
PRIORITY</replaceable></literal></term>
222
GnuTLS priority string for the TLS handshake with the
224
<citerefentry><refentrytitle>gnutls_priority_init
225
</refentrytitle><manvolnum>3</manvolnum></citerefentry>
226
for the syntax. The default is
227
"<literal>SECURE256:!CTYPE-X.509:+CTYPE-OPENPGP</literal>".
228
<emphasis>Warning</emphasis>: changing this may make the
229
TLS handshake fail, making communication with clients
236
<term><literal>--servicename <replaceable>NAME</replaceable>
240
Zeroconf service name. The default is
241
"<literal>Mandos</literal>". You only need to change this
242
if you for some reason want to run more than one server on
243
the same <emphasis>host</emphasis>. If there are name
244
collisions on the same <emphasis>network</emphasis>, the
245
new server will automatically rename itself to "Mandos
252
<term><literal>--configdir <replaceable>DIR</replaceable>
214
<term><option>--debug</option></term>
216
<xi:include href="mandos-options.xml" xpointer="debug"/>
221
<term><option>--debuglevel
222
<replaceable>LEVEL</replaceable></option></term>
225
Set the debugging log level.
226
<replaceable>LEVEL</replaceable> is a string, one of
227
<quote><literal>CRITICAL</literal></quote>,
228
<quote><literal>ERROR</literal></quote>,
229
<quote><literal>WARNING</literal></quote>,
230
<quote><literal>INFO</literal></quote>, or
231
<quote><literal>DEBUG</literal></quote>, in order of
232
increasing verbosity. The default level is
233
<quote><literal>WARNING</literal></quote>.
239
<term><option>--priority <replaceable>
240
PRIORITY</replaceable></option></term>
242
<xi:include href="mandos-options.xml" xpointer="priority"/>
247
<term><option>--servicename
248
<replaceable>NAME</replaceable></option></term>
250
<xi:include href="mandos-options.xml"
251
xpointer="servicename"/>
256
<term><option>--configdir
257
<replaceable>DIRECTORY</replaceable></option></term>
256
260
Directory to search for configuration files. Default is
257
"<literal>/etc/mandos</literal>". See <citerefentry>
258
<refentrytitle>mandos.conf</refentrytitle>
261
<quote><literal>/etc/mandos</literal></quote>. See
262
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
259
263
<manvolnum>5</manvolnum></citerefentry> and <citerefentry>
260
264
<refentrytitle>mandos-clients.conf</refentrytitle>
261
265
<manvolnum>5</manvolnum></citerefentry>.
267
<term><literal>--version</literal></term>
271
<term><option>--version</option></term>
270
274
Prints the program version and exit.
280
<term><option>--no-dbus</option></term>
282
<xi:include href="mandos-options.xml" xpointer="dbus"/>
284
See also <xref linkend="dbus_interface"/>.
290
<term><option>--no-ipv6</option></term>
292
<xi:include href="mandos-options.xml" xpointer="ipv6"/>
297
<term><option>--no-restore</option></term>
299
<xi:include href="mandos-options.xml" xpointer="restore"/>
301
See also <xref linkend="persistent_state"/>.
307
<term><option>--statedir
308
<replaceable>DIRECTORY</replaceable></option></term>
310
<xi:include href="mandos-options.xml" xpointer="statedir"/>
315
<term><option>--socket
316
<replaceable>FD</replaceable></option></term>
318
<xi:include href="mandos-options.xml" xpointer="socket"/>
323
<term><option>--foreground</option></term>
325
<xi:include href="mandos-options.xml"
326
xpointer="foreground"/>
331
<term><option>--no-zeroconf</option></term>
333
<xi:include href="mandos-options.xml" xpointer="zeroconf"/>
340
<refsect1 id="overview">
341
<title>OVERVIEW</title>
342
<xi:include href="overview.xml"/>
344
This program is the server part. It is a normal server program
345
and will run in a normal system environment, not in an initial
346
<acronym>RAM</acronym> disk environment.
277
350
<refsect1 id="protocol">
278
351
<title>NETWORK PROTOCOL</title>
280
353
The Mandos server announces itself as a Zeroconf service of type
281
"<literal>_mandos._tcp</literal>". The Mandos client connects
282
to the announced address and port, and sends a line of text
283
where the first whitespace-separated field is the protocol
284
version, which currently is "<literal>1</literal>". The client
285
and server then start a TLS protocol handshake with a slight
286
quirk: the Mandos server program acts as a TLS "client" while
287
the connecting Mandos client acts as a TLS "server". The Mandos
288
client must supply an OpenPGP certificate, and the fingerprint
289
of this certificate is used by the Mandos server to look up (in
290
a list read from a file at start time) which binary blob to give
291
the client. No other authentication or authorization is done by
354
<quote><literal>_mandos._tcp</literal></quote>. The Mandos
355
client connects to the announced address and port, and sends a
356
line of text where the first whitespace-separated field is the
357
protocol version, which currently is
358
<quote><literal>1</literal></quote>. The client and server then
359
start a TLS protocol handshake with a slight quirk: the Mandos
360
server program acts as a TLS <quote>client</quote> while the
361
connecting Mandos client acts as a TLS <quote>server</quote>.
362
The Mandos client must supply an OpenPGP certificate, and the
363
fingerprint of this certificate is used by the Mandos server to
364
look up (in a list read from <filename>clients.conf</filename>
365
at start time) which binary blob to give the client. No other
366
authentication or authorization is done by the server.
294
<informaltable><tgroup cols="3"><thead>
369
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
296
371
<entry>Mandos Client</entry>
297
372
<entry>Direction</entry>
320
397
<entry><-<!-- ← --></entry>
321
<entry>Binary blob</entry>
398
<entry>Binary blob (client will assume OpenPGP data)</entry>
325
402
<entry><-<!-- ← --></entry>
326
403
<entry>Close</entry>
328
</tbody></tgroup></informaltable>
405
</tbody></tgroup></table>
408
<refsect1 id="checking">
409
<title>CHECKING</title>
411
The server will, by default, continually check that the clients
412
are still up. If a client has not been confirmed as being up
413
for some time, the client is assumed to be compromised and is no
414
longer eligible to receive the encrypted password. (Manual
415
intervention is required to re-enable a client.) The timeout,
416
extended timeout, checker program, and interval between checks
417
can be configured both globally and per client; see
418
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
419
<manvolnum>5</manvolnum></citerefentry>.
423
<refsect1 id="approval">
424
<title>APPROVAL</title>
426
The server can be configured to require manual approval for a
427
client before it is sent its secret. The delay to wait for such
428
approval and the default action (approve or deny) can be
429
configured both globally and per client; see <citerefentry>
430
<refentrytitle>mandos-clients.conf</refentrytitle>
431
<manvolnum>5</manvolnum></citerefentry>. By default all clients
432
will be approved immediately without delay.
435
This can be used to deny a client its secret if not manually
436
approved within a specified time. It can also be used to make
437
the server delay before giving a client its secret, allowing
438
optional manual denying of this specific client.
331
443
<refsect1 id="logging">
332
444
<title>LOGGING</title>
334
The server will log a lot of information with various severity
336
<citerefentry><refentrytitle>syslog</refentrytitle>
337
<manvolnum>8</manvolnum></citerefentry>. With the
446
The server will send log message with various severity levels to
447
<filename class="devicefile">/dev/log</filename>. With the
338
448
<option>--debug</option> option, it will log even more messages,
339
449
and also show them on the console.
453
<refsect1 id="persistent_state">
454
<title>PERSISTENT STATE</title>
456
Client settings, initially read from
457
<filename>clients.conf</filename>, are persistent across
458
restarts, and run-time changes will override settings in
459
<filename>clients.conf</filename>. However, if a setting is
460
<emphasis>changed</emphasis> (or a client added, or removed) in
461
<filename>clients.conf</filename>, this will take precedence.
465
<refsect1 id="dbus_interface">
466
<title>D-BUS INTERFACE</title>
468
The server will by default provide a D-Bus system bus interface.
469
This interface will only be accessible by the root user or a
470
Mandos-specific user, if such a user exists. For documentation
471
of the D-Bus API, see the file <filename>DBUS-API</filename>.
343
475
<refsect1 id="exit_status">
344
476
<title>EXIT STATUS</title>
347
479
critical error is encountered.
483
<refsect1 id="environment">
484
<title>ENVIRONMENT</title>
487
<term><envar>PATH</envar></term>
490
To start the configured checker (see <xref
491
linkend="checking"/>), the server uses
492
<filename>/bin/sh</filename>, which in turn uses
493
<varname>PATH</varname> to search for matching commands if
494
an absolute path is not given. See <citerefentry>
495
<refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum>
503
<refsect1 id="files">
352
504
<title>FILES</title>
356
<filename>/etc/mandos/mandos.conf</filename> See <citerefentry>
357
<refentrytitle>mandos.conf</refentrytitle>
358
<manvolnum>5</manvolnum></citerefentry>.
361
<filename>/etc/mandos/clients.conf</filename> See <citerefentry>
506
Use the <option>--configdir</option> option to change where
507
<command>&COMMANDNAME;</command> looks for its configurations
508
files. The default file names are listed here.
512
<term><filename>/etc/mandos/mandos.conf</filename></term>
515
Server-global settings. See
516
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
517
<manvolnum>5</manvolnum></citerefentry> for details.
522
<term><filename>/etc/mandos/clients.conf</filename></term>
525
List of clients and client-specific settings. See
526
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
527
<manvolnum>5</manvolnum></citerefentry> for details.
532
<term><filename>/run/mandos.pid</filename></term>
535
The file containing the process id of the
536
<command>&COMMANDNAME;</command> process started last.
537
<emphasis >Note:</emphasis> If the <filename
538
class="directory">/run</filename> directory does not
539
exist, <filename>/var/run/mandos.pid</filename> will be
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 class="devicefile">/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>
362
570
<refentrytitle>mandos-clients.conf</refentrytitle>
363
<manvolnum>5</manvolnum></citerefentry>.
366
<filename>/var/run/mandos/mandos.pid</filename>
571
<manvolnum>5</manvolnum></citerefentry> for details.
372
578
<refsect1 id="bugs">
373
579
<title>BUGS</title>
378
<refsect1 id="examples">
379
<title>EXAMPLES</title>
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
591
<xi:include href="bugs.xml"/>
594
<refsect1 id="example">
595
<title>EXAMPLE</title>
598
Normal invocation needs no options:
601
<userinput>&COMMANDNAME;</userinput>
606
Run the server in debug mode, read configuration files from
607
the <filename class="directory">~/mandos</filename> directory,
608
and use the Zeroconf service name <quote>Test</quote> to not
609
collide with any other official Mandos server on this host:
613
<!-- do not wrap this line -->
614
<userinput>&COMMANDNAME; --debug --configdir ~/mandos --servicename Test</userinput>
620
Run the server normally, but only listen to one interface and
621
only on the link-local address on that interface:
625
<!-- do not wrap this line -->
626
<userinput>&COMMANDNAME; --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>
384
632
<refsect1 id="security">
385
633
<title>SECURITY</title>
634
<refsect2 id="server">
635
<title>SERVER</title>
637
Running this <command>&COMMANDNAME;</command> server program
638
should not in itself present any security risk to the host
639
computer running it. The program switches to a non-root user
643
<refsect2 id="clients">
644
<title>CLIENTS</title>
646
The server only gives out its stored data to clients which
647
does have the OpenPGP key of the stored fingerprint. This is
648
guaranteed by the fact that the client sends its OpenPGP
649
public key in the TLS handshake; this ensures it to be
650
genuine. The server computes the fingerprint of the key
651
itself and looks up the fingerprint in its list of
652
clients. The <filename>clients.conf</filename> file (see
653
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
654
<manvolnum>5</manvolnum></citerefentry>)
655
<emphasis>must</emphasis> be made non-readable by anyone
656
except the user starting the server (usually root).
659
As detailed in <xref linkend="checking"/>, the status of all
660
client computers will continually be checked and be assumed
661
compromised if they are gone for too long.
664
For more details on client-side security, see
665
<citerefentry><refentrytitle>mandos-client</refentrytitle>
666
<manvolnum>8mandos</manvolnum></citerefentry>.
390
671
<refsect1 id="see_also">
391
672
<title>SEE ALSO</title>
392
<itemizedlist spacing="compact">
394
<citerefentry><refentrytitle>password-request</refentrytitle>
395
<manvolnum>8mandos</manvolnum></citerefentry>
399
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
400
<manvolnum>8mandos</manvolnum></citerefentry>
404
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
408
<ulink url="http://www.avahi.org/">Avahi</ulink>
413
url="http://www.gnu.org/software/gnutls/">GnuTLS</ulink>
417
<citation>RFC 4880: <citetitle>OpenPGP Message
418
Format</citetitle></citation>
422
<citation>RFC 5081: <citetitle>Using OpenPGP Keys for
423
Transport Layer Security</citetitle></citation>
427
<citation>RFC 4291: <citetitle>IP Version 6 Addressing
428
Architecture</citetitle>, section 2.5.6, Link-Local IPv6
429
Unicast Addresses</citation>
674
<citerefentry><refentrytitle>intro</refentrytitle>
675
<manvolnum>8mandos</manvolnum></citerefentry>,
676
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
677
<manvolnum>5</manvolnum></citerefentry>,
678
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
679
<manvolnum>5</manvolnum></citerefentry>,
680
<citerefentry><refentrytitle>mandos-client</refentrytitle>
681
<manvolnum>8mandos</manvolnum></citerefentry>,
682
<citerefentry><refentrytitle>sh</refentrytitle>
683
<manvolnum>1</manvolnum></citerefentry>
688
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
692
Zeroconf is the network protocol standard used by clients
693
for finding this Mandos server on the local network.
699
<ulink url="http://www.avahi.org/">Avahi</ulink>
703
Avahi is the library this server calls to implement
704
Zeroconf service announcements.
710
<ulink url="http://gnutls.org/">GnuTLS</ulink>
714
GnuTLS is the library this server uses to implement TLS for
715
communicating securely with the client, and at the same time
716
confidently get the client’s public OpenPGP key.
722
RFC 4291: <citetitle>IP Version 6 Addressing
723
Architecture</citetitle>
728
<term>Section 2.2: <citetitle>Text Representation of
729
Addresses</citetitle></term>
730
<listitem><para/></listitem>
733
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
734
Address</citetitle></term>
735
<listitem><para/></listitem>
738
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
739
Addresses</citetitle></term>
742
The clients use IPv6 link-local addresses, which are
743
immediately usable since a link-local addresses is
744
automatically assigned to a network interfaces when it
754
RFC 5246: <citetitle>The Transport Layer Security (TLS)
755
Protocol Version 1.2</citetitle>
759
TLS 1.2 is the protocol implemented by GnuTLS.
765
RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
769
The data sent to clients is binary encrypted OpenPGP data.
775
RFC 6091: <citetitle>Using OpenPGP Keys for Transport Layer
776
Security (TLS) Authentication</citetitle>
780
This is implemented by GnuTLS and used by this server so
781
that OpenPGP keys can be used.
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