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"/>
293
<term><option>--statedir
294
<replaceable>DIRECTORY</replaceable></option></term>
296
<xi:include href="mandos-options.xml" xpointer="statedir"/>
302
<refsect1 id="overview">
303
<title>OVERVIEW</title>
304
<xi:include href="overview.xml"/>
306
This program is the server part. It is a normal server program
307
and will run in a normal system environment, not in an initial
308
<acronym>RAM</acronym> disk environment.
277
312
<refsect1 id="protocol">
278
313
<title>NETWORK PROTOCOL</title>
280
315
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
316
<quote><literal>_mandos._tcp</literal></quote>. The Mandos
317
client connects to the announced address and port, and sends a
318
line of text where the first whitespace-separated field is the
319
protocol version, which currently is
320
<quote><literal>1</literal></quote>. The client and server then
321
start a TLS protocol handshake with a slight quirk: the Mandos
322
server program acts as a TLS <quote>client</quote> while the
323
connecting Mandos client acts as a TLS <quote>server</quote>.
324
The Mandos client must supply an OpenPGP certificate, and the
325
fingerprint of this certificate is used by the Mandos server to
326
look up (in a list read from <filename>clients.conf</filename>
327
at start time) which binary blob to give the client. No other
328
authentication or authorization is done by the server.
294
<informaltable><tgroup cols="3"><thead>
331
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
296
333
<entry>Mandos Client</entry>
297
334
<entry>Direction</entry>
320
359
<entry><-<!-- ← --></entry>
321
<entry>Binary blob</entry>
360
<entry>Binary blob (client will assume OpenPGP data)</entry>
325
364
<entry><-<!-- ← --></entry>
326
365
<entry>Close</entry>
328
</tbody></tgroup></informaltable>
367
</tbody></tgroup></table>
370
<refsect1 id="checking">
371
<title>CHECKING</title>
373
The server will, by default, continually check that the clients
374
are still up. If a client has not been confirmed as being up
375
for some time, the client is assumed to be compromised and is no
376
longer eligible to receive the encrypted password. (Manual
377
intervention is required to re-enable a client.) The timeout,
378
extended timeout, checker program, and interval between checks
379
can be configured both globally and per client; see
380
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
381
<manvolnum>5</manvolnum></citerefentry>. A client successfully
382
receiving its password will also be treated as a successful
387
<refsect1 id="approval">
388
<title>APPROVAL</title>
390
The server can be configured to require manual approval for a
391
client before it is sent its secret. The delay to wait for such
392
approval and the default action (approve or deny) can be
393
configured both globally and per client; see <citerefentry>
394
<refentrytitle>mandos-clients.conf</refentrytitle>
395
<manvolnum>5</manvolnum></citerefentry>. By default all clients
396
will be approved immediately without delay.
399
This can be used to deny a client its secret if not manually
400
approved within a specified time. It can also be used to make
401
the server delay before giving a client its secret, allowing
402
optional manual denying of this specific client.
331
407
<refsect1 id="logging">
332
408
<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
410
The server will send log message with various severity levels to
411
<filename class="devicefile">/dev/log</filename>. With the
338
412
<option>--debug</option> option, it will log even more messages,
339
413
and also show them on the console.
417
<refsect1 id="dbus_interface">
418
<title>D-BUS INTERFACE</title>
420
The server will by default provide a D-Bus system bus interface.
421
This interface will only be accessible by the root user or a
422
Mandos-specific user, if such a user exists. For documentation
423
of the D-Bus API, see the file <filename>DBUS-API</filename>.
343
427
<refsect1 id="exit_status">
344
428
<title>EXIT STATUS</title>
347
431
critical error is encountered.
435
<refsect1 id="environment">
436
<title>ENVIRONMENT</title>
439
<term><envar>PATH</envar></term>
442
To start the configured checker (see <xref
443
linkend="checking"/>), the server uses
444
<filename>/bin/sh</filename>, which in turn uses
445
<varname>PATH</varname> to search for matching commands if
446
an absolute path is not given. See <citerefentry>
447
<refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum>
455
<refsect1 id="files">
352
456
<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>
458
Use the <option>--configdir</option> option to change where
459
<command>&COMMANDNAME;</command> looks for its configurations
460
files. The default file names are listed here.
464
<term><filename>/etc/mandos/mandos.conf</filename></term>
467
Server-global settings. See
468
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
469
<manvolnum>5</manvolnum></citerefentry> for details.
474
<term><filename>/etc/mandos/clients.conf</filename></term>
477
List of clients and client-specific settings. See
478
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
479
<manvolnum>5</manvolnum></citerefentry> for details.
484
<term><filename>/var/run/mandos.pid</filename></term>
487
The file containing the process id of the
488
<command>&COMMANDNAME;</command> process started last.
493
<term><filename class="devicefile">/dev/log</filename></term>
497
class="directory">/var/lib/mandos</filename></term>
500
Directory where persistent state will be saved. Change
501
this with the <option>--statedir</option> option. See
502
also the <option>--no-restore</option> option.
507
<term><filename>/dev/log</filename></term>
510
The Unix domain socket to where local syslog messages are
516
<term><filename>/bin/sh</filename></term>
519
This is used to start the configured checker command for
520
each client. See <citerefentry>
362
521
<refentrytitle>mandos-clients.conf</refentrytitle>
363
<manvolnum>5</manvolnum></citerefentry>.
366
<filename>/var/run/mandos/mandos.pid</filename>
522
<manvolnum>5</manvolnum></citerefentry> for details.
372
529
<refsect1 id="bugs">
373
530
<title>BUGS</title>
378
<refsect1 id="examples">
379
<title>EXAMPLES</title>
532
This server might, on especially fatal errors, emit a Python
533
backtrace. This could be considered a feature.
536
There is no fine-grained control over logging and debug output.
539
Debug mode is conflated with running in the foreground.
542
This server does not check the expire time of clients’ OpenPGP
547
<refsect1 id="example">
548
<title>EXAMPLE</title>
551
Normal invocation needs no options:
554
<userinput>&COMMANDNAME;</userinput>
559
Run the server in debug mode, read configuration files from
560
the <filename class="directory">~/mandos</filename> directory,
561
and use the Zeroconf service name <quote>Test</quote> to not
562
collide with any other official Mandos server on this host:
566
<!-- do not wrap this line -->
567
<userinput>&COMMANDNAME; --debug --configdir ~/mandos --servicename Test</userinput>
573
Run the server normally, but only listen to one interface and
574
only on the link-local address on that interface:
578
<!-- do not wrap this line -->
579
<userinput>&COMMANDNAME; --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>
384
585
<refsect1 id="security">
385
586
<title>SECURITY</title>
587
<refsect2 id="server">
588
<title>SERVER</title>
590
Running this <command>&COMMANDNAME;</command> server program
591
should not in itself present any security risk to the host
592
computer running it. The program switches to a non-root user
596
<refsect2 id="clients">
597
<title>CLIENTS</title>
599
The server only gives out its stored data to clients which
600
does have the OpenPGP key of the stored fingerprint. This is
601
guaranteed by the fact that the client sends its OpenPGP
602
public key in the TLS handshake; this ensures it to be
603
genuine. The server computes the fingerprint of the key
604
itself and looks up the fingerprint in its list of
605
clients. The <filename>clients.conf</filename> file (see
606
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
607
<manvolnum>5</manvolnum></citerefentry>)
608
<emphasis>must</emphasis> be made non-readable by anyone
609
except the user starting the server (usually root).
612
As detailed in <xref linkend="checking"/>, the status of all
613
client computers will continually be checked and be assumed
614
compromised if they are gone for too long.
617
For more details on client-side security, see
618
<citerefentry><refentrytitle>mandos-client</refentrytitle>
619
<manvolnum>8mandos</manvolnum></citerefentry>.
390
624
<refsect1 id="see_also">
391
625
<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>
627
<citerefentry><refentrytitle>intro</refentrytitle>
628
<manvolnum>8mandos</manvolnum></citerefentry>,
629
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
630
<manvolnum>5</manvolnum></citerefentry>,
631
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
632
<manvolnum>5</manvolnum></citerefentry>,
633
<citerefentry><refentrytitle>mandos-client</refentrytitle>
634
<manvolnum>8mandos</manvolnum></citerefentry>,
635
<citerefentry><refentrytitle>sh</refentrytitle>
636
<manvolnum>1</manvolnum></citerefentry>
641
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
645
Zeroconf is the network protocol standard used by clients
646
for finding this Mandos server on the local network.
652
<ulink url="http://www.avahi.org/">Avahi</ulink>
656
Avahi is the library this server calls to implement
657
Zeroconf service announcements.
663
<ulink url="http://www.gnu.org/software/gnutls/"
668
GnuTLS is the library this server uses to implement TLS for
669
communicating securely with the client, and at the same time
670
confidently get the client’s public OpenPGP key.
676
RFC 4291: <citetitle>IP Version 6 Addressing
677
Architecture</citetitle>
682
<term>Section 2.2: <citetitle>Text Representation of
683
Addresses</citetitle></term>
684
<listitem><para/></listitem>
687
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
688
Address</citetitle></term>
689
<listitem><para/></listitem>
692
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
693
Addresses</citetitle></term>
696
The clients use IPv6 link-local addresses, which are
697
immediately usable since a link-local addresses is
698
automatically assigned to a network interfaces when it
708
RFC 4346: <citetitle>The Transport Layer Security (TLS)
709
Protocol Version 1.1</citetitle>
713
TLS 1.1 is the protocol implemented by GnuTLS.
719
RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
723
The data sent to clients is binary encrypted OpenPGP data.
729
RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer
734
This is implemented by GnuTLS and used by this server so
735
that OpenPGP keys can be used.
742
<!-- Local Variables: -->
743
<!-- time-stamp-start: "<!ENTITY TIMESTAMP [\"']" -->
744
<!-- time-stamp-end: "[\"']>" -->
745
<!-- time-stamp-format: "%:y-%02m-%02d" -->