56
68
<refname><command>&COMMANDNAME;</command></refname>
58
Gives encrypted passwords to authenticated Mandos clients
70
Sends encrypted passwords to authenticated Mandos clients
64
76
<command>&COMMANDNAME;</command>
66
<arg choice="plain"><option>--interface
67
<replaceable>NAME</replaceable></option></arg>
68
<arg choice="plain"><option>-i
69
<replaceable>NAME</replaceable></option></arg>
73
<arg choice="plain"><option>--address
74
<replaceable>ADDRESS</replaceable></option></arg>
75
<arg choice="plain"><option>-a
76
<replaceable>ADDRESS</replaceable></option></arg>
80
<arg choice="plain"><option>--port
81
<replaceable>PORT</replaceable></option></arg>
82
<arg choice="plain"><option>-p
83
<replaceable>PORT</replaceable></option></arg>
86
<arg><option>--priority
87
<replaceable>PRIORITY</replaceable></option></arg>
89
<arg><option>--servicename
90
<replaceable>NAME</replaceable></option></arg>
92
<arg><option>--configdir
93
<replaceable>DIRECTORY</replaceable></option></arg>
95
<arg><option>--debug</option></arg>
97
<arg><option>--debuglevel
98
<replaceable>LEVEL</replaceable></option></arg>
100
<arg><option>--no-dbus</option></arg>
102
<arg><option>--no-ipv6</option></arg>
104
<arg><option>--no-restore</option></arg>
106
<arg><option>--statedir
107
<replaceable>DIRECTORY</replaceable></option></arg>
109
<arg><option>--socket
110
<replaceable>FD</replaceable></option></arg>
112
<arg><option>--foreground</option></arg>
114
<arg><option>--no-zeroconf</option></arg>
117
<command>&COMMANDNAME;</command>
119
<arg choice="plain"><option>--help</option></arg>
120
<arg choice="plain"><option>-h</option></arg>
124
<command>&COMMANDNAME;</command>
125
<arg choice="plain"><option>--version</option></arg>
128
<command>&COMMANDNAME;</command>
129
<arg choice="plain"><option>--check</option></arg>
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>
131
107
</refsynopsisdiv>
133
109
<refsect1 id="description">
134
110
<title>DESCRIPTION</title>
136
112
<command>&COMMANDNAME;</command> is a server daemon which
137
113
handles incoming request for passwords for a pre-defined list of
138
client host computers. For an introduction, see
139
<citerefentry><refentrytitle>intro</refentrytitle>
140
<manvolnum>8mandos</manvolnum></citerefentry>. The Mandos server
141
uses Zeroconf to announce itself on the local network, and uses
142
TLS to communicate securely with and to authenticate the
143
clients. The Mandos server uses IPv6 to allow Mandos clients to
144
use IPv6 link-local addresses, since the clients will probably
145
not have any other addresses configured (see <xref
146
linkend="overview"/>). Any authenticated client is then given
147
the stored pre-encrypted password for that specific client.
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.
151
125
<refsect1 id="purpose">
152
126
<title>PURPOSE</title>
154
129
The purpose of this is to enable <emphasis>remote and unattended
155
rebooting</emphasis> of client host computer with an
156
<emphasis>encrypted root file system</emphasis>. See <xref
157
linkend="overview"/> for details.
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
161
142
<refsect1 id="options">
162
143
<title>OPTIONS</title>
165
<term><option>--help</option></term>
166
<term><option>-h</option></term>
147
<term><literal>-h</literal>, <literal>--help</literal></term>
169
150
Show a help message and exit
175
<term><option>--interface</option>
176
<replaceable>NAME</replaceable></term>
177
<term><option>-i</option>
178
<replaceable>NAME</replaceable></term>
180
<xi:include href="mandos-options.xml" xpointer="interface"/>
185
<term><option>--address
186
<replaceable>ADDRESS</replaceable></option></term>
188
<replaceable>ADDRESS</replaceable></option></term>
190
<xi:include href="mandos-options.xml" xpointer="address"/>
196
<replaceable>PORT</replaceable></option></term>
198
<replaceable>PORT</replaceable></option></term>
200
<xi:include href="mandos-options.xml" xpointer="port"/>
205
<term><option>--check</option></term>
208
Run the server’s self-tests. This includes any unit
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
215
<term><option>--debug</option></term>
217
<xi:include href="mandos-options.xml" xpointer="debug"/>
222
<term><option>--debuglevel
223
<replaceable>LEVEL</replaceable></option></term>
226
Set the debugging log level.
227
<replaceable>LEVEL</replaceable> is a string, one of
228
<quote><literal>CRITICAL</literal></quote>,
229
<quote><literal>ERROR</literal></quote>,
230
<quote><literal>WARNING</literal></quote>,
231
<quote><literal>INFO</literal></quote>, or
232
<quote><literal>DEBUG</literal></quote>, in order of
233
increasing verbosity. The default level is
234
<quote><literal>WARNING</literal></quote>.
240
<term><option>--priority <replaceable>
241
PRIORITY</replaceable></option></term>
243
<xi:include href="mandos-options.xml" xpointer="priority"/>
248
<term><option>--servicename
249
<replaceable>NAME</replaceable></option></term>
251
<xi:include href="mandos-options.xml"
252
xpointer="servicename"/>
257
<term><option>--configdir
258
<replaceable>DIRECTORY</replaceable></option></term>
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>
261
256
Directory to search for configuration files. Default is
262
<quote><literal>/etc/mandos</literal></quote>. See
263
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
257
"<literal>/etc/mandos</literal>". See <citerefentry>
258
<refentrytitle>mandos.conf</refentrytitle>
264
259
<manvolnum>5</manvolnum></citerefentry> and <citerefentry>
265
260
<refentrytitle>mandos-clients.conf</refentrytitle>
266
261
<manvolnum>5</manvolnum></citerefentry>.
272
<term><option>--version</option></term>
267
<term><literal>--version</literal></term>
275
270
Prints the program version and exit.
281
<term><option>--no-dbus</option></term>
283
<xi:include href="mandos-options.xml" xpointer="dbus"/>
285
See also <xref linkend="dbus_interface"/>.
291
<term><option>--no-ipv6</option></term>
293
<xi:include href="mandos-options.xml" xpointer="ipv6"/>
298
<term><option>--no-restore</option></term>
300
<xi:include href="mandos-options.xml" xpointer="restore"/>
302
See also <xref linkend="persistent_state"/>.
308
<term><option>--statedir
309
<replaceable>DIRECTORY</replaceable></option></term>
311
<xi:include href="mandos-options.xml" xpointer="statedir"/>
316
<term><option>--socket
317
<replaceable>FD</replaceable></option></term>
319
<xi:include href="mandos-options.xml" xpointer="socket"/>
324
<term><option>--foreground</option></term>
326
<xi:include href="mandos-options.xml"
327
xpointer="foreground"/>
332
<term><option>--no-zeroconf</option></term>
334
<xi:include href="mandos-options.xml" xpointer="zeroconf"/>
341
<refsect1 id="overview">
342
<title>OVERVIEW</title>
343
<xi:include href="overview.xml"/>
345
This program is the server part. It is a normal server program
346
and will run in a normal system environment, not in an initial
347
<acronym>RAM</acronym> disk environment.
351
277
<refsect1 id="protocol">
352
278
<title>NETWORK PROTOCOL</title>
354
280
The Mandos server announces itself as a Zeroconf service of type
355
<quote><literal>_mandos._tcp</literal></quote>. The Mandos
356
client connects to the announced address and port, and sends a
357
line of text where the first whitespace-separated field is the
358
protocol version, which currently is
359
<quote><literal>1</literal></quote>. The client and server then
360
start a TLS protocol handshake with a slight quirk: the Mandos
361
server program acts as a TLS <quote>client</quote> while the
362
connecting Mandos client acts as a TLS <quote>server</quote>.
363
The Mandos client must supply an OpenPGP certificate, and the
364
fingerprint of this certificate is used by the Mandos server to
365
look up (in a list read from <filename>clients.conf</filename>
366
at start time) which binary blob to give the client. No other
367
authentication or authorization is done by the server.
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
370
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
294
<informaltable><tgroup cols="3"><thead>
372
296
<entry>Mandos Client</entry>
373
297
<entry>Direction</entry>
398
320
<entry><-<!-- ← --></entry>
399
<entry>Binary blob (client will assume OpenPGP data)</entry>
321
<entry>Binary blob</entry>
403
325
<entry><-<!-- ← --></entry>
404
326
<entry>Close</entry>
406
</tbody></tgroup></table>
409
<refsect1 id="checking">
410
<title>CHECKING</title>
412
The server will, by default, continually check that the clients
413
are still up. If a client has not been confirmed as being up
414
for some time, the client is assumed to be compromised and is no
415
longer eligible to receive the encrypted password. (Manual
416
intervention is required to re-enable a client.) The timeout,
417
extended timeout, checker program, and interval between checks
418
can be configured both globally and per client; see
419
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
420
<manvolnum>5</manvolnum></citerefentry>.
424
<refsect1 id="approval">
425
<title>APPROVAL</title>
427
The server can be configured to require manual approval for a
428
client before it is sent its secret. The delay to wait for such
429
approval and the default action (approve or deny) can be
430
configured both globally and per client; see <citerefentry>
431
<refentrytitle>mandos-clients.conf</refentrytitle>
432
<manvolnum>5</manvolnum></citerefentry>. By default all clients
433
will be approved immediately without delay.
436
This can be used to deny a client its secret if not manually
437
approved within a specified time. It can also be used to make
438
the server delay before giving a client its secret, allowing
439
optional manual denying of this specific client.
328
</tbody></tgroup></informaltable>
444
331
<refsect1 id="logging">
445
332
<title>LOGGING</title>
447
The server will send log message with various severity levels to
448
<filename class="devicefile">/dev/log</filename>. With the
334
The server will log a lot of information with various severity
336
<citerefentry><refentrytitle>syslog</refentrytitle>
337
<manvolnum>8</manvolnum></citerefentry>. With the
449
338
<option>--debug</option> option, it will log even more messages,
450
339
and also show them on the console.
454
<refsect1 id="persistent_state">
455
<title>PERSISTENT STATE</title>
457
Client settings, initially read from
458
<filename>clients.conf</filename>, are persistent across
459
restarts, and run-time changes will override settings in
460
<filename>clients.conf</filename>. However, if a setting is
461
<emphasis>changed</emphasis> (or a client added, or removed) in
462
<filename>clients.conf</filename>, this will take precedence.
466
<refsect1 id="dbus_interface">
467
<title>D-BUS INTERFACE</title>
469
The server will by default provide a D-Bus system bus interface.
470
This interface will only be accessible by the root user or a
471
Mandos-specific user, if such a user exists. For documentation
472
of the D-Bus API, see the file <filename>DBUS-API</filename>.
476
343
<refsect1 id="exit_status">
477
344
<title>EXIT STATUS</title>
480
347
critical error is encountered.
484
<refsect1 id="environment">
485
<title>ENVIRONMENT</title>
488
<term><envar>PATH</envar></term>
491
To start the configured checker (see <xref
492
linkend="checking"/>), the server uses
493
<filename>/bin/sh</filename>, which in turn uses
494
<varname>PATH</varname> to search for matching commands if
495
an absolute path is not given. See <citerefentry>
496
<refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum>
504
<refsect1 id="files">
505
352
<title>FILES</title>
507
Use the <option>--configdir</option> option to change where
508
<command>&COMMANDNAME;</command> looks for its configurations
509
files. The default file names are listed here.
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>
362
<refentrytitle>mandos-clients.conf</refentrytitle>
363
<manvolnum>5</manvolnum></citerefentry>.
366
<filename>/var/run/mandos/mandos.pid</filename>
513
<term><filename>/etc/mandos/mandos.conf</filename></term>
516
Server-global settings. See
517
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
518
<manvolnum>5</manvolnum></citerefentry> for details.
523
<term><filename>/etc/mandos/clients.conf</filename></term>
526
List of clients and client-specific settings. See
527
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
528
<manvolnum>5</manvolnum></citerefentry> for details.
533
<term><filename>/run/mandos.pid</filename></term>
536
The file containing the process id of the
537
<command>&COMMANDNAME;</command> process started last.
538
<emphasis >Note:</emphasis> If the <filename
539
class="directory">/run</filename> directory does not
540
exist, <filename>/var/run/mandos.pid</filename> will be
547
class="directory">/var/lib/mandos</filename></term>
550
Directory where persistent state will be saved. Change
551
this with the <option>--statedir</option> option. See
552
also the <option>--no-restore</option> option.
557
<term><filename class="devicefile">/dev/log</filename></term>
560
The Unix domain socket to where local syslog messages are
566
<term><filename>/bin/sh</filename></term>
569
This is used to start the configured checker command for
570
each client. See <citerefentry>
571
<refentrytitle>mandos-clients.conf</refentrytitle>
572
<manvolnum>5</manvolnum></citerefentry> for details.
579
372
<refsect1 id="bugs">
580
373
<title>BUGS</title>
582
This server might, on especially fatal errors, emit a Python
583
backtrace. This could be considered a feature.
586
There is no fine-grained control over logging and debug output.
589
This server does not check the expire time of clients’ OpenPGP
592
<xi:include href="bugs.xml"/>
595
<refsect1 id="example">
596
<title>EXAMPLE</title>
599
Normal invocation needs no options:
602
<userinput>&COMMANDNAME;</userinput>
607
Run the server in debug mode, read configuration files from
608
the <filename class="directory">~/mandos</filename> directory,
609
and use the Zeroconf service name <quote>Test</quote> to not
610
collide with any other official Mandos server on this host:
614
<!-- do not wrap this line -->
615
<userinput>&COMMANDNAME; --debug --configdir ~/mandos --servicename Test</userinput>
621
Run the server normally, but only listen to one interface and
622
only on the link-local address on that interface:
626
<!-- do not wrap this line -->
627
<userinput>&COMMANDNAME; --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>
378
<refsect1 id="examples">
379
<title>EXAMPLES</title>
633
384
<refsect1 id="security">
634
385
<title>SECURITY</title>
635
<refsect2 id="server">
636
<title>SERVER</title>
638
Running this <command>&COMMANDNAME;</command> server program
639
should not in itself present any security risk to the host
640
computer running it. The program switches to a non-root user
644
<refsect2 id="clients">
645
<title>CLIENTS</title>
647
The server only gives out its stored data to clients which
648
does have the OpenPGP key of the stored fingerprint. This is
649
guaranteed by the fact that the client sends its OpenPGP
650
public key in the TLS handshake; this ensures it to be
651
genuine. The server computes the fingerprint of the key
652
itself and looks up the fingerprint in its list of
653
clients. The <filename>clients.conf</filename> file (see
654
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
655
<manvolnum>5</manvolnum></citerefentry>)
656
<emphasis>must</emphasis> be made non-readable by anyone
657
except the user starting the server (usually root).
660
As detailed in <xref linkend="checking"/>, the status of all
661
client computers will continually be checked and be assumed
662
compromised if they are gone for too long.
665
For more details on client-side security, see
666
<citerefentry><refentrytitle>mandos-client</refentrytitle>
667
<manvolnum>8mandos</manvolnum></citerefentry>.
672
390
<refsect1 id="see_also">
673
391
<title>SEE ALSO</title>
675
<citerefentry><refentrytitle>intro</refentrytitle>
676
<manvolnum>8mandos</manvolnum></citerefentry>,
677
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
678
<manvolnum>5</manvolnum></citerefentry>,
679
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
680
<manvolnum>5</manvolnum></citerefentry>,
681
<citerefentry><refentrytitle>mandos-client</refentrytitle>
682
<manvolnum>8mandos</manvolnum></citerefentry>,
683
<citerefentry><refentrytitle>sh</refentrytitle>
684
<manvolnum>1</manvolnum></citerefentry>
689
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
693
Zeroconf is the network protocol standard used by clients
694
for finding this Mandos server on the local network.
700
<ulink url="http://www.avahi.org/">Avahi</ulink>
704
Avahi is the library this server calls to implement
705
Zeroconf service announcements.
711
<ulink url="https://gnutls.org/">GnuTLS</ulink>
715
GnuTLS is the library this server uses to implement TLS for
716
communicating securely with the client, and at the same time
717
confidently get the client’s public OpenPGP key.
723
RFC 4291: <citetitle>IP Version 6 Addressing
724
Architecture</citetitle>
729
<term>Section 2.2: <citetitle>Text Representation of
730
Addresses</citetitle></term>
731
<listitem><para/></listitem>
734
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
735
Address</citetitle></term>
736
<listitem><para/></listitem>
739
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
740
Addresses</citetitle></term>
743
The clients use IPv6 link-local addresses, which are
744
immediately usable since a link-local addresses is
745
automatically assigned to a network interfaces when it
755
RFC 5246: <citetitle>The Transport Layer Security (TLS)
756
Protocol Version 1.2</citetitle>
760
TLS 1.2 is the protocol implemented by GnuTLS.
766
RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
770
The data sent to clients is binary encrypted OpenPGP data.
776
RFC 6091: <citetitle>Using OpenPGP Keys for Transport Layer
777
Security (TLS) Authentication</citetitle>
781
This is implemented by GnuTLS and used by this server so
782
that OpenPGP keys can be used.
392
<itemizedlist spacing="compact">
394
<citerefentry><refentrytitle>password-request</refentrytitle>
395
<manvolnum>8mandos</manvolnum></citerefentry>
399
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
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<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>
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