68
52
<refname><command>&COMMANDNAME;</command></refname>
70
Sends encrypted passwords to authenticated Mandos clients
54
Gives encrypted passwords to authenticated Mandos clients
76
60
<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>
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>
111
<command>&COMMANDNAME;</command>
113
<arg choice="plain"><option>--help</option></arg>
114
<arg choice="plain"><option>-h</option></arg>
118
<command>&COMMANDNAME;</command>
119
<arg choice="plain"><option>--version</option></arg>
122
<command>&COMMANDNAME;</command>
123
<arg choice="plain"><option>--check</option></arg>
107
125
</refsynopsisdiv>
109
127
<refsect1 id="description">
110
128
<title>DESCRIPTION</title>
112
130
<command>&COMMANDNAME;</command> is a server daemon which
113
131
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.
132
client host computers. For an introduction, see
133
<citerefentry><refentrytitle>intro</refentrytitle>
134
<manvolnum>8mandos</manvolnum></citerefentry>. The Mandos server
135
uses Zeroconf to announce itself on the local network, and uses
136
TLS to communicate securely with and to authenticate the
137
clients. The Mandos server uses IPv6 to allow Mandos clients to
138
use IPv6 link-local addresses, since the clients will probably
139
not have any other addresses configured (see <xref
140
linkend="overview"/>). Any authenticated client is then given
141
the stored pre-encrypted password for that specific client.
125
145
<refsect1 id="purpose">
126
146
<title>PURPOSE</title>
129
148
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
149
rebooting</emphasis> of client host computer with an
150
<emphasis>encrypted root file system</emphasis>. See <xref
151
linkend="overview"/> for details.
142
155
<refsect1 id="options">
143
156
<title>OPTIONS</title>
147
<term><literal>-h</literal>, <literal>--help</literal></term>
159
<term><option>--help</option></term>
160
<term><option>-h</option></term>
150
163
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
169
<term><option>--interface</option>
170
<replaceable>NAME</replaceable></term>
171
<term><option>-i</option>
172
<replaceable>NAME</replaceable></term>
174
<xi:include href="mandos-options.xml" xpointer="interface"/>
179
<term><option>--address
180
<replaceable>ADDRESS</replaceable></option></term>
182
<replaceable>ADDRESS</replaceable></option></term>
184
<xi:include href="mandos-options.xml" xpointer="address"/>
190
<replaceable>PORT</replaceable></option></term>
192
<replaceable>PORT</replaceable></option></term>
194
<xi:include href="mandos-options.xml" xpointer="port"/>
199
<term><option>--check</option></term>
202
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>
209
<term><option>--debug</option></term>
211
<xi:include href="mandos-options.xml" xpointer="debug"/>
216
<term><option>--debuglevel
217
<replaceable>LEVEL</replaceable></option></term>
220
Set the debugging log level.
221
<replaceable>LEVEL</replaceable> is a string, one of
222
<quote><literal>CRITICAL</literal></quote>,
223
<quote><literal>ERROR</literal></quote>,
224
<quote><literal>WARNING</literal></quote>,
225
<quote><literal>INFO</literal></quote>, or
226
<quote><literal>DEBUG</literal></quote>, in order of
227
increasing verbosity. The default level is
228
<quote><literal>WARNING</literal></quote>.
234
<term><option>--priority <replaceable>
235
PRIORITY</replaceable></option></term>
237
<xi:include href="mandos-options.xml" xpointer="priority"/>
242
<term><option>--servicename
243
<replaceable>NAME</replaceable></option></term>
245
<xi:include href="mandos-options.xml"
246
xpointer="servicename"/>
251
<term><option>--configdir
252
<replaceable>DIRECTORY</replaceable></option></term>
256
255
Directory to search for configuration files. Default is
257
"<literal>/etc/mandos</literal>". See <citerefentry>
258
<refentrytitle>mandos.conf</refentrytitle>
256
<quote><literal>/etc/mandos</literal></quote>. See
257
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
259
258
<manvolnum>5</manvolnum></citerefentry> and <citerefentry>
260
259
<refentrytitle>mandos-clients.conf</refentrytitle>
261
260
<manvolnum>5</manvolnum></citerefentry>.
267
<term><literal>--version</literal></term>
266
<term><option>--version</option></term>
270
269
Prints the program version and exit.
275
<term><option>--no-dbus</option></term>
277
<xi:include href="mandos-options.xml" xpointer="dbus"/>
279
See also <xref linkend="dbus_interface"/>.
285
<term><option>--no-ipv6</option></term>
287
<xi:include href="mandos-options.xml" xpointer="ipv6"/>
292
<term><option>--no-restore</option></term>
294
<xi:include href="mandos-options.xml" xpointer="restore"/>
296
See also <xref linkend="persistent_state"/>.
302
<term><option>--statedir
303
<replaceable>DIRECTORY</replaceable></option></term>
305
<xi:include href="mandos-options.xml" xpointer="statedir"/>
310
<term><option>--socket
311
<replaceable>FD</replaceable></option></term>
313
<xi:include href="mandos-options.xml" xpointer="socket"/>
318
<term><option>--foreground</option></term>
320
<xi:include href="mandos-options.xml"
321
xpointer="foreground"/>
328
<refsect1 id="overview">
329
<title>OVERVIEW</title>
330
<xi:include href="overview.xml"/>
332
This program is the server part. It is a normal server program
333
and will run in a normal system environment, not in an initial
334
<acronym>RAM</acronym> disk environment.
277
338
<refsect1 id="protocol">
278
339
<title>NETWORK PROTOCOL</title>
280
341
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
342
<quote><literal>_mandos._tcp</literal></quote>. The Mandos
343
client connects to the announced address and port, and sends a
344
line of text where the first whitespace-separated field is the
345
protocol version, which currently is
346
<quote><literal>1</literal></quote>. The client and server then
347
start a TLS protocol handshake with a slight quirk: the Mandos
348
server program acts as a TLS <quote>client</quote> while the
349
connecting Mandos client acts as a TLS <quote>server</quote>.
350
The Mandos client must supply an OpenPGP certificate, and the
351
fingerprint of this certificate is used by the Mandos server to
352
look up (in a list read from <filename>clients.conf</filename>
353
at start time) which binary blob to give the client. No other
354
authentication or authorization is done by the server.
294
<informaltable><tgroup cols="3"><thead>
357
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
296
359
<entry>Mandos Client</entry>
297
360
<entry>Direction</entry>
320
385
<entry><-<!-- ← --></entry>
321
<entry>Binary blob</entry>
386
<entry>Binary blob (client will assume OpenPGP data)</entry>
325
390
<entry><-<!-- ← --></entry>
326
391
<entry>Close</entry>
328
</tbody></tgroup></informaltable>
393
</tbody></tgroup></table>
396
<refsect1 id="checking">
397
<title>CHECKING</title>
399
The server will, by default, continually check that the clients
400
are still up. If a client has not been confirmed as being up
401
for some time, the client is assumed to be compromised and is no
402
longer eligible to receive the encrypted password. (Manual
403
intervention is required to re-enable a client.) The timeout,
404
extended timeout, checker program, and interval between checks
405
can be configured both globally and per client; see
406
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
407
<manvolnum>5</manvolnum></citerefentry>.
411
<refsect1 id="approval">
412
<title>APPROVAL</title>
414
The server can be configured to require manual approval for a
415
client before it is sent its secret. The delay to wait for such
416
approval and the default action (approve or deny) can be
417
configured both globally and per client; see <citerefentry>
418
<refentrytitle>mandos-clients.conf</refentrytitle>
419
<manvolnum>5</manvolnum></citerefentry>. By default all clients
420
will be approved immediately without delay.
423
This can be used to deny a client its secret if not manually
424
approved within a specified time. It can also be used to make
425
the server delay before giving a client its secret, allowing
426
optional manual denying of this specific client.
331
431
<refsect1 id="logging">
332
432
<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
434
The server will send log message with various severity levels to
435
<filename class="devicefile">/dev/log</filename>. With the
338
436
<option>--debug</option> option, it will log even more messages,
339
437
and also show them on the console.
441
<refsect1 id="persistent_state">
442
<title>PERSISTENT STATE</title>
444
Client settings, initially read from
445
<filename>clients.conf</filename>, are persistent across
446
restarts, and run-time changes will override settings in
447
<filename>clients.conf</filename>. However, if a setting is
448
<emphasis>changed</emphasis> (or a client added, or removed) in
449
<filename>clients.conf</filename>, this will take precedence.
453
<refsect1 id="dbus_interface">
454
<title>D-BUS INTERFACE</title>
456
The server will by default provide a D-Bus system bus interface.
457
This interface will only be accessible by the root user or a
458
Mandos-specific user, if such a user exists. For documentation
459
of the D-Bus API, see the file <filename>DBUS-API</filename>.
343
463
<refsect1 id="exit_status">
344
464
<title>EXIT STATUS</title>
347
467
critical error is encountered.
471
<refsect1 id="environment">
472
<title>ENVIRONMENT</title>
475
<term><envar>PATH</envar></term>
478
To start the configured checker (see <xref
479
linkend="checking"/>), the server uses
480
<filename>/bin/sh</filename>, which in turn uses
481
<varname>PATH</varname> to search for matching commands if
482
an absolute path is not given. See <citerefentry>
483
<refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum>
491
<refsect1 id="files">
352
492
<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>
494
Use the <option>--configdir</option> option to change where
495
<command>&COMMANDNAME;</command> looks for its configurations
496
files. The default file names are listed here.
500
<term><filename>/etc/mandos/mandos.conf</filename></term>
503
Server-global settings. See
504
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
505
<manvolnum>5</manvolnum></citerefentry> for details.
510
<term><filename>/etc/mandos/clients.conf</filename></term>
513
List of clients and client-specific settings. See
514
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
515
<manvolnum>5</manvolnum></citerefentry> for details.
520
<term><filename>/run/mandos.pid</filename></term>
523
The file containing the process id of the
524
<command>&COMMANDNAME;</command> process started last.
529
<term><filename class="devicefile">/dev/log</filename></term>
533
class="directory">/var/lib/mandos</filename></term>
536
Directory where persistent state will be saved. Change
537
this with the <option>--statedir</option> option. See
538
also the <option>--no-restore</option> option.
543
<term><filename>/dev/log</filename></term>
546
The Unix domain socket to where local syslog messages are
552
<term><filename>/bin/sh</filename></term>
555
This is used to start the configured checker command for
556
each client. See <citerefentry>
362
557
<refentrytitle>mandos-clients.conf</refentrytitle>
363
<manvolnum>5</manvolnum></citerefentry>.
366
<filename>/var/run/mandos/mandos.pid</filename>
558
<manvolnum>5</manvolnum></citerefentry> for details.
372
565
<refsect1 id="bugs">
373
566
<title>BUGS</title>
378
<refsect1 id="examples">
379
<title>EXAMPLES</title>
568
This server might, on especially fatal errors, emit a Python
569
backtrace. This could be considered a feature.
572
There is no fine-grained control over logging and debug output.
575
This server does not check the expire time of clients’ OpenPGP
580
<refsect1 id="example">
581
<title>EXAMPLE</title>
584
Normal invocation needs no options:
587
<userinput>&COMMANDNAME;</userinput>
592
Run the server in debug mode, read configuration files from
593
the <filename class="directory">~/mandos</filename> directory,
594
and use the Zeroconf service name <quote>Test</quote> to not
595
collide with any other official Mandos server on this host:
599
<!-- do not wrap this line -->
600
<userinput>&COMMANDNAME; --debug --configdir ~/mandos --servicename Test</userinput>
606
Run the server normally, but only listen to one interface and
607
only on the link-local address on that interface:
611
<!-- do not wrap this line -->
612
<userinput>&COMMANDNAME; --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>
384
618
<refsect1 id="security">
385
619
<title>SECURITY</title>
620
<refsect2 id="server">
621
<title>SERVER</title>
623
Running this <command>&COMMANDNAME;</command> server program
624
should not in itself present any security risk to the host
625
computer running it. The program switches to a non-root user
629
<refsect2 id="clients">
630
<title>CLIENTS</title>
632
The server only gives out its stored data to clients which
633
does have the OpenPGP key of the stored fingerprint. This is
634
guaranteed by the fact that the client sends its OpenPGP
635
public key in the TLS handshake; this ensures it to be
636
genuine. The server computes the fingerprint of the key
637
itself and looks up the fingerprint in its list of
638
clients. The <filename>clients.conf</filename> file (see
639
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
640
<manvolnum>5</manvolnum></citerefentry>)
641
<emphasis>must</emphasis> be made non-readable by anyone
642
except the user starting the server (usually root).
645
As detailed in <xref linkend="checking"/>, the status of all
646
client computers will continually be checked and be assumed
647
compromised if they are gone for too long.
650
For more details on client-side security, see
651
<citerefentry><refentrytitle>mandos-client</refentrytitle>
652
<manvolnum>8mandos</manvolnum></citerefentry>.
390
657
<refsect1 id="see_also">
391
658
<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>
660
<citerefentry><refentrytitle>intro</refentrytitle>
661
<manvolnum>8mandos</manvolnum></citerefentry>,
662
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
663
<manvolnum>5</manvolnum></citerefentry>,
664
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
665
<manvolnum>5</manvolnum></citerefentry>,
666
<citerefentry><refentrytitle>mandos-client</refentrytitle>
667
<manvolnum>8mandos</manvolnum></citerefentry>,
668
<citerefentry><refentrytitle>sh</refentrytitle>
669
<manvolnum>1</manvolnum></citerefentry>
674
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
678
Zeroconf is the network protocol standard used by clients
679
for finding this Mandos server on the local network.
685
<ulink url="http://www.avahi.org/">Avahi</ulink>
689
Avahi is the library this server calls to implement
690
Zeroconf service announcements.
696
<ulink url="http://www.gnu.org/software/gnutls/"
701
GnuTLS is the library this server uses to implement TLS for
702
communicating securely with the client, and at the same time
703
confidently get the client’s public OpenPGP key.
709
RFC 4291: <citetitle>IP Version 6 Addressing
710
Architecture</citetitle>
715
<term>Section 2.2: <citetitle>Text Representation of
716
Addresses</citetitle></term>
717
<listitem><para/></listitem>
720
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
721
Address</citetitle></term>
722
<listitem><para/></listitem>
725
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
726
Addresses</citetitle></term>
729
The clients use IPv6 link-local addresses, which are
730
immediately usable since a link-local addresses is
731
automatically assigned to a network interfaces when it
741
RFC 4346: <citetitle>The Transport Layer Security (TLS)
742
Protocol Version 1.1</citetitle>
746
TLS 1.1 is the protocol implemented by GnuTLS.
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RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
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The data sent to clients is binary encrypted OpenPGP data.
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RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer
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This is implemented by GnuTLS and used by this server so
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that OpenPGP keys can be used.
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