68
51
<refname><command>&COMMANDNAME;</command></refname>
70
Sends encrypted passwords to authenticated Mandos clients
53
Gives encrypted passwords to authenticated Mandos clients
76
59
<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>
61
<arg choice="plain"><option>--interface
62
<replaceable>NAME</replaceable></option></arg>
63
<arg choice="plain"><option>-i
64
<replaceable>NAME</replaceable></option></arg>
68
<arg choice="plain"><option>--address
69
<replaceable>ADDRESS</replaceable></option></arg>
70
<arg choice="plain"><option>-a
71
<replaceable>ADDRESS</replaceable></option></arg>
75
<arg choice="plain"><option>--port
76
<replaceable>PORT</replaceable></option></arg>
77
<arg choice="plain"><option>-p
78
<replaceable>PORT</replaceable></option></arg>
81
<arg><option>--priority
82
<replaceable>PRIORITY</replaceable></option></arg>
84
<arg><option>--servicename
85
<replaceable>NAME</replaceable></option></arg>
87
<arg><option>--configdir
88
<replaceable>DIRECTORY</replaceable></option></arg>
90
<arg><option>--debug</option></arg>
92
<arg><option>--debuglevel
93
<replaceable>LEVEL</replaceable></option></arg>
95
<arg><option>--no-dbus</option></arg>
97
<arg><option>--no-ipv6</option></arg>
99
<arg><option>--no-restore</option></arg>
101
<arg><option>--statedir
102
<replaceable>DIRECTORY</replaceable></option></arg>
105
<command>&COMMANDNAME;</command>
107
<arg choice="plain"><option>--help</option></arg>
108
<arg choice="plain"><option>-h</option></arg>
112
<command>&COMMANDNAME;</command>
113
<arg choice="plain"><option>--version</option></arg>
116
<command>&COMMANDNAME;</command>
117
<arg choice="plain"><option>--check</option></arg>
107
119
</refsynopsisdiv>
109
121
<refsect1 id="description">
110
122
<title>DESCRIPTION</title>
112
124
<command>&COMMANDNAME;</command> is a server daemon which
113
125
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.
126
client host computers. For an introduction, see
127
<citerefentry><refentrytitle>intro</refentrytitle>
128
<manvolnum>8mandos</manvolnum></citerefentry>. The Mandos server
129
uses Zeroconf to announce itself on the local network, and uses
130
TLS to communicate securely with and to authenticate the
131
clients. The Mandos server uses IPv6 to allow Mandos clients to
132
use IPv6 link-local addresses, since the clients will probably
133
not have any other addresses configured (see <xref
134
linkend="overview"/>). Any authenticated client is then given
135
the stored pre-encrypted password for that specific client.
125
139
<refsect1 id="purpose">
126
140
<title>PURPOSE</title>
129
142
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
143
rebooting</emphasis> of client host computer with an
144
<emphasis>encrypted root file system</emphasis>. See <xref
145
linkend="overview"/> for details.
142
149
<refsect1 id="options">
143
150
<title>OPTIONS</title>
147
<term><literal>-h</literal>, <literal>--help</literal></term>
153
<term><option>--help</option></term>
154
<term><option>-h</option></term>
150
157
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
163
<term><option>--interface</option>
164
<replaceable>NAME</replaceable></term>
165
<term><option>-i</option>
166
<replaceable>NAME</replaceable></term>
168
<xi:include href="mandos-options.xml" xpointer="interface"/>
173
<term><option>--address
174
<replaceable>ADDRESS</replaceable></option></term>
176
<replaceable>ADDRESS</replaceable></option></term>
178
<xi:include href="mandos-options.xml" xpointer="address"/>
184
<replaceable>PORT</replaceable></option></term>
186
<replaceable>PORT</replaceable></option></term>
188
<xi:include href="mandos-options.xml" xpointer="port"/>
193
<term><option>--check</option></term>
196
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>
203
<term><option>--debug</option></term>
205
<xi:include href="mandos-options.xml" xpointer="debug"/>
210
<term><option>--debuglevel
211
<replaceable>LEVEL</replaceable></option></term>
214
Set the debugging log level.
215
<replaceable>LEVEL</replaceable> is a string, one of
216
<quote><literal>CRITICAL</literal></quote>,
217
<quote><literal>ERROR</literal></quote>,
218
<quote><literal>WARNING</literal></quote>,
219
<quote><literal>INFO</literal></quote>, or
220
<quote><literal>DEBUG</literal></quote>, in order of
221
increasing verbosity. The default level is
222
<quote><literal>WARNING</literal></quote>.
228
<term><option>--priority <replaceable>
229
PRIORITY</replaceable></option></term>
231
<xi:include href="mandos-options.xml" xpointer="priority"/>
236
<term><option>--servicename
237
<replaceable>NAME</replaceable></option></term>
239
<xi:include href="mandos-options.xml"
240
xpointer="servicename"/>
245
<term><option>--configdir
246
<replaceable>DIRECTORY</replaceable></option></term>
256
249
Directory to search for configuration files. Default is
257
"<literal>/etc/mandos</literal>". See <citerefentry>
258
<refentrytitle>mandos.conf</refentrytitle>
250
<quote><literal>/etc/mandos</literal></quote>. See
251
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
259
252
<manvolnum>5</manvolnum></citerefentry> and <citerefentry>
260
253
<refentrytitle>mandos-clients.conf</refentrytitle>
261
254
<manvolnum>5</manvolnum></citerefentry>.
267
<term><literal>--version</literal></term>
260
<term><option>--version</option></term>
270
263
Prints the program version and exit.
269
<term><option>--no-dbus</option></term>
271
<xi:include href="mandos-options.xml" xpointer="dbus"/>
273
See also <xref linkend="dbus_interface"/>.
279
<term><option>--no-ipv6</option></term>
281
<xi:include href="mandos-options.xml" xpointer="ipv6"/>
286
<term><option>--no-restore</option></term>
288
<xi:include href="mandos-options.xml" xpointer="restore"/>
290
See also <xref linkend="persistent_state"/>.
296
<term><option>--statedir
297
<replaceable>DIRECTORY</replaceable></option></term>
299
<xi:include href="mandos-options.xml" xpointer="statedir"/>
305
<refsect1 id="overview">
306
<title>OVERVIEW</title>
307
<xi:include href="overview.xml"/>
309
This program is the server part. It is a normal server program
310
and will run in a normal system environment, not in an initial
311
<acronym>RAM</acronym> disk environment.
277
315
<refsect1 id="protocol">
278
316
<title>NETWORK PROTOCOL</title>
280
318
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
319
<quote><literal>_mandos._tcp</literal></quote>. The Mandos
320
client connects to the announced address and port, and sends a
321
line of text where the first whitespace-separated field is the
322
protocol version, which currently is
323
<quote><literal>1</literal></quote>. The client and server then
324
start a TLS protocol handshake with a slight quirk: the Mandos
325
server program acts as a TLS <quote>client</quote> while the
326
connecting Mandos client acts as a TLS <quote>server</quote>.
327
The Mandos client must supply an OpenPGP certificate, and the
328
fingerprint of this certificate is used by the Mandos server to
329
look up (in a list read from <filename>clients.conf</filename>
330
at start time) which binary blob to give the client. No other
331
authentication or authorization is done by the server.
294
<informaltable><tgroup cols="3"><thead>
334
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
296
336
<entry>Mandos Client</entry>
297
337
<entry>Direction</entry>
320
362
<entry><-<!-- ← --></entry>
321
<entry>Binary blob</entry>
363
<entry>Binary blob (client will assume OpenPGP data)</entry>
325
367
<entry><-<!-- ← --></entry>
326
368
<entry>Close</entry>
328
</tbody></tgroup></informaltable>
370
</tbody></tgroup></table>
373
<refsect1 id="checking">
374
<title>CHECKING</title>
376
The server will, by default, continually check that the clients
377
are still up. If a client has not been confirmed as being up
378
for some time, the client is assumed to be compromised and is no
379
longer eligible to receive the encrypted password. (Manual
380
intervention is required to re-enable a client.) The timeout,
381
extended timeout, checker program, and interval between checks
382
can be configured both globally and per client; see
383
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
384
<manvolnum>5</manvolnum></citerefentry>. A client successfully
385
receiving its password will also be treated as a successful
390
<refsect1 id="approval">
391
<title>APPROVAL</title>
393
The server can be configured to require manual approval for a
394
client before it is sent its secret. The delay to wait for such
395
approval and the default action (approve or deny) can be
396
configured both globally and per client; see <citerefentry>
397
<refentrytitle>mandos-clients.conf</refentrytitle>
398
<manvolnum>5</manvolnum></citerefentry>. By default all clients
399
will be approved immediately without delay.
402
This can be used to deny a client its secret if not manually
403
approved within a specified time. It can also be used to make
404
the server delay before giving a client its secret, allowing
405
optional manual denying of this specific client.
331
410
<refsect1 id="logging">
332
411
<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
413
The server will send log message with various severity levels to
414
<filename class="devicefile">/dev/log</filename>. With the
338
415
<option>--debug</option> option, it will log even more messages,
339
416
and also show them on the console.
420
<refsect1 id="persistent_state">
421
<title>PERSISTENT STATE</title>
423
Client settings, initially read from
424
<filename>clients.conf</filename>, are persistent across
425
restarts, and run-time changes will override settings in
426
<filename>clients.conf</filename>. However, if a setting is
427
<emphasis>changed</emphasis> (or a client added, or removed) in
428
<filename>clients.conf</filename>, this will take precedence.
432
<refsect1 id="dbus_interface">
433
<title>D-BUS INTERFACE</title>
435
The server will by default provide a D-Bus system bus interface.
436
This interface will only be accessible by the root user or a
437
Mandos-specific user, if such a user exists. For documentation
438
of the D-Bus API, see the file <filename>DBUS-API</filename>.
343
442
<refsect1 id="exit_status">
344
443
<title>EXIT STATUS</title>
347
446
critical error is encountered.
450
<refsect1 id="environment">
451
<title>ENVIRONMENT</title>
454
<term><envar>PATH</envar></term>
457
To start the configured checker (see <xref
458
linkend="checking"/>), the server uses
459
<filename>/bin/sh</filename>, which in turn uses
460
<varname>PATH</varname> to search for matching commands if
461
an absolute path is not given. See <citerefentry>
462
<refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum>
470
<refsect1 id="files">
352
471
<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>
473
Use the <option>--configdir</option> option to change where
474
<command>&COMMANDNAME;</command> looks for its configurations
475
files. The default file names are listed here.
479
<term><filename>/etc/mandos/mandos.conf</filename></term>
482
Server-global settings. See
483
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
484
<manvolnum>5</manvolnum></citerefentry> for details.
489
<term><filename>/etc/mandos/clients.conf</filename></term>
492
List of clients and client-specific settings. See
493
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
494
<manvolnum>5</manvolnum></citerefentry> for details.
499
<term><filename>/var/run/mandos.pid</filename></term>
502
The file containing the process id of the
503
<command>&COMMANDNAME;</command> process started last.
508
<term><filename class="devicefile">/dev/log</filename></term>
512
class="directory">/var/lib/mandos</filename></term>
515
Directory where persistent state will be saved. Change
516
this with the <option>--statedir</option> option. See
517
also the <option>--no-restore</option> option.
522
<term><filename>/dev/log</filename></term>
525
The Unix domain socket to where local syslog messages are
531
<term><filename>/bin/sh</filename></term>
534
This is used to start the configured checker command for
535
each client. See <citerefentry>
362
536
<refentrytitle>mandos-clients.conf</refentrytitle>
363
<manvolnum>5</manvolnum></citerefentry>.
366
<filename>/var/run/mandos/mandos.pid</filename>
537
<manvolnum>5</manvolnum></citerefentry> for details.
372
544
<refsect1 id="bugs">
373
545
<title>BUGS</title>
378
<refsect1 id="examples">
379
<title>EXAMPLES</title>
547
This server might, on especially fatal errors, emit a Python
548
backtrace. This could be considered a feature.
551
There is no fine-grained control over logging and debug output.
554
Debug mode is conflated with running in the foreground.
557
This server does not check the expire time of clients’ OpenPGP
562
<refsect1 id="example">
563
<title>EXAMPLE</title>
566
Normal invocation needs no options:
569
<userinput>&COMMANDNAME;</userinput>
574
Run the server in debug mode, read configuration files from
575
the <filename class="directory">~/mandos</filename> directory,
576
and use the Zeroconf service name <quote>Test</quote> to not
577
collide with any other official Mandos server on this host:
581
<!-- do not wrap this line -->
582
<userinput>&COMMANDNAME; --debug --configdir ~/mandos --servicename Test</userinput>
588
Run the server normally, but only listen to one interface and
589
only on the link-local address on that interface:
593
<!-- do not wrap this line -->
594
<userinput>&COMMANDNAME; --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>
384
600
<refsect1 id="security">
385
601
<title>SECURITY</title>
602
<refsect2 id="server">
603
<title>SERVER</title>
605
Running this <command>&COMMANDNAME;</command> server program
606
should not in itself present any security risk to the host
607
computer running it. The program switches to a non-root user
611
<refsect2 id="clients">
612
<title>CLIENTS</title>
614
The server only gives out its stored data to clients which
615
does have the OpenPGP key of the stored fingerprint. This is
616
guaranteed by the fact that the client sends its OpenPGP
617
public key in the TLS handshake; this ensures it to be
618
genuine. The server computes the fingerprint of the key
619
itself and looks up the fingerprint in its list of
620
clients. The <filename>clients.conf</filename> file (see
621
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
622
<manvolnum>5</manvolnum></citerefentry>)
623
<emphasis>must</emphasis> be made non-readable by anyone
624
except the user starting the server (usually root).
627
As detailed in <xref linkend="checking"/>, the status of all
628
client computers will continually be checked and be assumed
629
compromised if they are gone for too long.
632
For more details on client-side security, see
633
<citerefentry><refentrytitle>mandos-client</refentrytitle>
634
<manvolnum>8mandos</manvolnum></citerefentry>.
390
639
<refsect1 id="see_also">
391
640
<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>
642
<citerefentry><refentrytitle>intro</refentrytitle>
643
<manvolnum>8mandos</manvolnum></citerefentry>,
644
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
645
<manvolnum>5</manvolnum></citerefentry>,
646
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
647
<manvolnum>5</manvolnum></citerefentry>,
648
<citerefentry><refentrytitle>mandos-client</refentrytitle>
649
<manvolnum>8mandos</manvolnum></citerefentry>,
650
<citerefentry><refentrytitle>sh</refentrytitle>
651
<manvolnum>1</manvolnum></citerefentry>
656
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
660
Zeroconf is the network protocol standard used by clients
661
for finding this Mandos server on the local network.
667
<ulink url="http://www.avahi.org/">Avahi</ulink>
671
Avahi is the library this server calls to implement
672
Zeroconf service announcements.
678
<ulink url="http://www.gnu.org/software/gnutls/"
683
GnuTLS is the library this server uses to implement TLS for
684
communicating securely with the client, and at the same time
685
confidently get the client’s public OpenPGP key.
691
RFC 4291: <citetitle>IP Version 6 Addressing
692
Architecture</citetitle>
697
<term>Section 2.2: <citetitle>Text Representation of
698
Addresses</citetitle></term>
699
<listitem><para/></listitem>
702
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
703
Address</citetitle></term>
704
<listitem><para/></listitem>
707
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
708
Addresses</citetitle></term>
711
The clients use IPv6 link-local addresses, which are
712
immediately usable since a link-local addresses is
713
automatically assigned to a network interfaces when it
723
RFC 4346: <citetitle>The Transport Layer Security (TLS)
724
Protocol Version 1.1</citetitle>
728
TLS 1.1 is the protocol implemented by GnuTLS.
734
RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
738
The data sent to clients is binary encrypted OpenPGP data.
744
RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer
749
This is implemented by GnuTLS and used by this server so
750
that OpenPGP keys can be used.
757
<!-- Local Variables: -->
758
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759
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760
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