68
50
<refname><command>&COMMANDNAME;</command></refname>
70
Sends encrypted passwords to authenticated Mandos clients
52
Gives encrypted passwords to authenticated Mandos clients
76
58
<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>
60
<arg choice="plain"><option>--interface
61
<replaceable>NAME</replaceable></option></arg>
62
<arg choice="plain"><option>-i
63
<replaceable>NAME</replaceable></option></arg>
67
<arg choice="plain"><option>--address
68
<replaceable>ADDRESS</replaceable></option></arg>
69
<arg choice="plain"><option>-a
70
<replaceable>ADDRESS</replaceable></option></arg>
74
<arg choice="plain"><option>--port
75
<replaceable>PORT</replaceable></option></arg>
76
<arg choice="plain"><option>-p
77
<replaceable>PORT</replaceable></option></arg>
80
<arg><option>--priority
81
<replaceable>PRIORITY</replaceable></option></arg>
83
<arg><option>--servicename
84
<replaceable>NAME</replaceable></option></arg>
86
<arg><option>--configdir
87
<replaceable>DIRECTORY</replaceable></option></arg>
89
<arg><option>--debug</option></arg>
91
<arg><option>--debuglevel
92
<replaceable>LEVEL</replaceable></option></arg>
94
<arg><option>--no-dbus</option></arg>
96
<arg><option>--no-ipv6</option></arg>
98
<arg><option>--no-restore</option></arg>
100
<arg><option>--statedir
101
<replaceable>DIRECTORY</replaceable></option></arg>
104
<command>&COMMANDNAME;</command>
106
<arg choice="plain"><option>--help</option></arg>
107
<arg choice="plain"><option>-h</option></arg>
111
<command>&COMMANDNAME;</command>
112
<arg choice="plain"><option>--version</option></arg>
115
<command>&COMMANDNAME;</command>
116
<arg choice="plain"><option>--check</option></arg>
107
118
</refsynopsisdiv>
109
120
<refsect1 id="description">
110
121
<title>DESCRIPTION</title>
112
123
<command>&COMMANDNAME;</command> is a server daemon which
113
124
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.
125
client host computers. For an introduction, see
126
<citerefentry><refentrytitle>intro</refentrytitle>
127
<manvolnum>8mandos</manvolnum></citerefentry>. The Mandos server
128
uses Zeroconf to announce itself on the local network, and uses
129
TLS to communicate securely with and to authenticate the
130
clients. The Mandos server uses IPv6 to allow Mandos clients to
131
use IPv6 link-local addresses, since the clients will probably
132
not have any other addresses configured (see <xref
133
linkend="overview"/>). Any authenticated client is then given
134
the stored pre-encrypted password for that specific client.
125
138
<refsect1 id="purpose">
126
139
<title>PURPOSE</title>
129
141
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
142
rebooting</emphasis> of client host computer with an
143
<emphasis>encrypted root file system</emphasis>. See <xref
144
linkend="overview"/> for details.
142
148
<refsect1 id="options">
143
149
<title>OPTIONS</title>
147
<term><literal>-h</literal>, <literal>--help</literal></term>
152
<term><option>--help</option></term>
153
<term><option>-h</option></term>
150
156
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
162
<term><option>--interface</option>
163
<replaceable>NAME</replaceable></term>
164
<term><option>-i</option>
165
<replaceable>NAME</replaceable></term>
167
<xi:include href="mandos-options.xml" xpointer="interface"/>
172
<term><option>--address
173
<replaceable>ADDRESS</replaceable></option></term>
175
<replaceable>ADDRESS</replaceable></option></term>
177
<xi:include href="mandos-options.xml" xpointer="address"/>
183
<replaceable>PORT</replaceable></option></term>
185
<replaceable>PORT</replaceable></option></term>
187
<xi:include href="mandos-options.xml" xpointer="port"/>
192
<term><option>--check</option></term>
195
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>
202
<term><option>--debug</option></term>
204
<xi:include href="mandos-options.xml" xpointer="debug"/>
209
<term><option>--debuglevel
210
<replaceable>LEVEL</replaceable></option></term>
213
Set the debugging log level.
214
<replaceable>LEVEL</replaceable> is a string, one of
215
<quote><literal>CRITICAL</literal></quote>,
216
<quote><literal>ERROR</literal></quote>,
217
<quote><literal>WARNING</literal></quote>,
218
<quote><literal>INFO</literal></quote>, or
219
<quote><literal>DEBUG</literal></quote>, in order of
220
increasing verbosity. The default level is
221
<quote><literal>WARNING</literal></quote>.
227
<term><option>--priority <replaceable>
228
PRIORITY</replaceable></option></term>
230
<xi:include href="mandos-options.xml" xpointer="priority"/>
235
<term><option>--servicename
236
<replaceable>NAME</replaceable></option></term>
238
<xi:include href="mandos-options.xml"
239
xpointer="servicename"/>
244
<term><option>--configdir
245
<replaceable>DIRECTORY</replaceable></option></term>
256
248
Directory to search for configuration files. Default is
257
"<literal>/etc/mandos</literal>". See <citerefentry>
258
<refentrytitle>mandos.conf</refentrytitle>
249
<quote><literal>/etc/mandos</literal></quote>. See
250
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
259
251
<manvolnum>5</manvolnum></citerefentry> and <citerefentry>
260
252
<refentrytitle>mandos-clients.conf</refentrytitle>
261
253
<manvolnum>5</manvolnum></citerefentry>.
267
<term><literal>--version</literal></term>
259
<term><option>--version</option></term>
270
262
Prints the program version and exit.
268
<term><option>--no-dbus</option></term>
270
<xi:include href="mandos-options.xml" xpointer="dbus"/>
272
See also <xref linkend="dbus_interface"/>.
278
<term><option>--no-ipv6</option></term>
280
<xi:include href="mandos-options.xml" xpointer="ipv6"/>
285
<term><option>--no-restore</option></term>
287
<xi:include href="mandos-options.xml" xpointer="restore"/>
292
<term><option>--statedir
293
<replaceable>DIRECTORY</replaceable></option></term>
295
<xi:include href="mandos-options.xml" xpointer="statedir"/>
301
<refsect1 id="overview">
302
<title>OVERVIEW</title>
303
<xi:include href="overview.xml"/>
305
This program is the server part. It is a normal server program
306
and will run in a normal system environment, not in an initial
307
<acronym>RAM</acronym> disk environment.
277
311
<refsect1 id="protocol">
278
312
<title>NETWORK PROTOCOL</title>
280
314
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
315
<quote><literal>_mandos._tcp</literal></quote>. The Mandos
316
client connects to the announced address and port, and sends a
317
line of text where the first whitespace-separated field is the
318
protocol version, which currently is
319
<quote><literal>1</literal></quote>. The client and server then
320
start a TLS protocol handshake with a slight quirk: the Mandos
321
server program acts as a TLS <quote>client</quote> while the
322
connecting Mandos client acts as a TLS <quote>server</quote>.
323
The Mandos client must supply an OpenPGP certificate, and the
324
fingerprint of this certificate is used by the Mandos server to
325
look up (in a list read from <filename>clients.conf</filename>
326
at start time) which binary blob to give the client. No other
327
authentication or authorization is done by the server.
294
<informaltable><tgroup cols="3"><thead>
330
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
296
332
<entry>Mandos Client</entry>
297
333
<entry>Direction</entry>
320
358
<entry><-<!-- ← --></entry>
321
<entry>Binary blob</entry>
359
<entry>Binary blob (client will assume OpenPGP data)</entry>
325
363
<entry><-<!-- ← --></entry>
326
364
<entry>Close</entry>
328
</tbody></tgroup></informaltable>
366
</tbody></tgroup></table>
369
<refsect1 id="checking">
370
<title>CHECKING</title>
372
The server will, by default, continually check that the clients
373
are still up. If a client has not been confirmed as being up
374
for some time, the client is assumed to be compromised and is no
375
longer eligible to receive the encrypted password. (Manual
376
intervention is required to re-enable a client.) The timeout,
377
extended timeout, checker program, and interval between checks
378
can be configured both globally and per client; see
379
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
380
<manvolnum>5</manvolnum></citerefentry>. A client successfully
381
receiving its password will also be treated as a successful
386
<refsect1 id="approval">
387
<title>APPROVAL</title>
389
The server can be configured to require manual approval for a
390
client before it is sent its secret. The delay to wait for such
391
approval and the default action (approve or deny) can be
392
configured both globally and per client; see <citerefentry>
393
<refentrytitle>mandos-clients.conf</refentrytitle>
394
<manvolnum>5</manvolnum></citerefentry>. By default all clients
395
will be approved immediately without delay.
398
This can be used to deny a client its secret if not manually
399
approved within a specified time. It can also be used to make
400
the server delay before giving a client its secret, allowing
401
optional manual denying of this specific client.
331
406
<refsect1 id="logging">
332
407
<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
409
The server will send log message with various severity levels to
410
<filename class="devicefile">/dev/log</filename>. With the
338
411
<option>--debug</option> option, it will log even more messages,
339
412
and also show them on the console.
416
<refsect1 id="dbus_interface">
417
<title>D-BUS INTERFACE</title>
419
The server will by default provide a D-Bus system bus interface.
420
This interface will only be accessible by the root user or a
421
Mandos-specific user, if such a user exists. For documentation
422
of the D-Bus API, see the file <filename>DBUS-API</filename>.
343
426
<refsect1 id="exit_status">
344
427
<title>EXIT STATUS</title>
347
430
critical error is encountered.
434
<refsect1 id="environment">
435
<title>ENVIRONMENT</title>
438
<term><envar>PATH</envar></term>
441
To start the configured checker (see <xref
442
linkend="checking"/>), the server uses
443
<filename>/bin/sh</filename>, which in turn uses
444
<varname>PATH</varname> to search for matching commands if
445
an absolute path is not given. See <citerefentry>
446
<refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum>
454
<refsect1 id="files">
352
455
<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>
457
Use the <option>--configdir</option> option to change where
458
<command>&COMMANDNAME;</command> looks for its configurations
459
files. The default file names are listed here.
463
<term><filename>/etc/mandos/mandos.conf</filename></term>
466
Server-global settings. See
467
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
468
<manvolnum>5</manvolnum></citerefentry> for details.
473
<term><filename>/etc/mandos/clients.conf</filename></term>
476
List of clients and client-specific settings. See
477
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
478
<manvolnum>5</manvolnum></citerefentry> for details.
483
<term><filename>/var/run/mandos.pid</filename></term>
486
The file containing the process id of the
487
<command>&COMMANDNAME;</command> process started last.
492
<term><filename class="devicefile">/dev/log</filename></term>
496
class="directory">/var/lib/mandos</filename></term>
499
Directory where persistent state will be saved. Change
500
this with the <option>--statedir</option> option. See
501
also the <option>--no-restore</option> option.
506
<term><filename>/dev/log</filename></term>
509
The Unix domain socket to where local syslog messages are
515
<term><filename>/bin/sh</filename></term>
518
This is used to start the configured checker command for
519
each client. See <citerefentry>
362
520
<refentrytitle>mandos-clients.conf</refentrytitle>
363
<manvolnum>5</manvolnum></citerefentry>.
366
<filename>/var/run/mandos/mandos.pid</filename>
521
<manvolnum>5</manvolnum></citerefentry> for details.
372
528
<refsect1 id="bugs">
373
529
<title>BUGS</title>
378
<refsect1 id="examples">
379
<title>EXAMPLES</title>
531
This server might, on especially fatal errors, emit a Python
532
backtrace. This could be considered a feature.
535
There is no fine-grained control over logging and debug output.
538
Debug mode is conflated with running in the foreground.
541
This server does not check the expire time of clients’ OpenPGP
546
<refsect1 id="example">
547
<title>EXAMPLE</title>
550
Normal invocation needs no options:
553
<userinput>&COMMANDNAME;</userinput>
558
Run the server in debug mode, read configuration files from
559
the <filename class="directory">~/mandos</filename> directory,
560
and use the Zeroconf service name <quote>Test</quote> to not
561
collide with any other official Mandos server on this host:
565
<!-- do not wrap this line -->
566
<userinput>&COMMANDNAME; --debug --configdir ~/mandos --servicename Test</userinput>
572
Run the server normally, but only listen to one interface and
573
only on the link-local address on that interface:
577
<!-- do not wrap this line -->
578
<userinput>&COMMANDNAME; --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>
384
584
<refsect1 id="security">
385
585
<title>SECURITY</title>
586
<refsect2 id="server">
587
<title>SERVER</title>
589
Running this <command>&COMMANDNAME;</command> server program
590
should not in itself present any security risk to the host
591
computer running it. The program switches to a non-root user
595
<refsect2 id="clients">
596
<title>CLIENTS</title>
598
The server only gives out its stored data to clients which
599
does have the OpenPGP key of the stored fingerprint. This is
600
guaranteed by the fact that the client sends its OpenPGP
601
public key in the TLS handshake; this ensures it to be
602
genuine. The server computes the fingerprint of the key
603
itself and looks up the fingerprint in its list of
604
clients. The <filename>clients.conf</filename> file (see
605
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
606
<manvolnum>5</manvolnum></citerefentry>)
607
<emphasis>must</emphasis> be made non-readable by anyone
608
except the user starting the server (usually root).
611
As detailed in <xref linkend="checking"/>, the status of all
612
client computers will continually be checked and be assumed
613
compromised if they are gone for too long.
616
For more details on client-side security, see
617
<citerefentry><refentrytitle>mandos-client</refentrytitle>
618
<manvolnum>8mandos</manvolnum></citerefentry>.
390
623
<refsect1 id="see_also">
391
624
<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>
626
<citerefentry><refentrytitle>intro</refentrytitle>
627
<manvolnum>8mandos</manvolnum></citerefentry>,
628
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
629
<manvolnum>5</manvolnum></citerefentry>,
630
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
631
<manvolnum>5</manvolnum></citerefentry>,
632
<citerefentry><refentrytitle>mandos-client</refentrytitle>
633
<manvolnum>8mandos</manvolnum></citerefentry>,
634
<citerefentry><refentrytitle>sh</refentrytitle>
635
<manvolnum>1</manvolnum></citerefentry>
640
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
644
Zeroconf is the network protocol standard used by clients
645
for finding this Mandos server on the local network.
651
<ulink url="http://www.avahi.org/">Avahi</ulink>
655
Avahi is the library this server calls to implement
656
Zeroconf service announcements.
662
<ulink url="http://www.gnu.org/software/gnutls/"
667
GnuTLS is the library this server uses to implement TLS for
668
communicating securely with the client, and at the same time
669
confidently get the client’s public OpenPGP key.
675
RFC 4291: <citetitle>IP Version 6 Addressing
676
Architecture</citetitle>
681
<term>Section 2.2: <citetitle>Text Representation of
682
Addresses</citetitle></term>
683
<listitem><para/></listitem>
686
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
687
Address</citetitle></term>
688
<listitem><para/></listitem>
691
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
692
Addresses</citetitle></term>
695
The clients use IPv6 link-local addresses, which are
696
immediately usable since a link-local addresses is
697
automatically assigned to a network interfaces when it
707
RFC 4346: <citetitle>The Transport Layer Security (TLS)
708
Protocol Version 1.1</citetitle>
712
TLS 1.1 is the protocol implemented by GnuTLS.
718
RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
722
The data sent to clients is binary encrypted OpenPGP data.
728
RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer
733
This is implemented by GnuTLS and used by this server so
734
that OpenPGP keys can be used.
741
<!-- Local Variables: -->
742
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743
<!-- time-stamp-end: "[\"']>" -->
744
<!-- time-stamp-format: "%:y-%02m-%02d" -->