67
54
<refname><command>&COMMANDNAME;</command></refname>
69
Sends encrypted passwords to authenticated mandos clients
56
Gives encrypted passwords to authenticated Mandos clients
75
62
<command>&COMMANDNAME;</command>
76
<arg choice='opt' rep='repeat'>OPTION</arg>
64
<arg choice="plain"><option>--interface
65
<replaceable>NAME</replaceable></option></arg>
66
<arg choice="plain"><option>-i
67
<replaceable>NAME</replaceable></option></arg>
71
<arg choice="plain"><option>--address
72
<replaceable>ADDRESS</replaceable></option></arg>
73
<arg choice="plain"><option>-a
74
<replaceable>ADDRESS</replaceable></option></arg>
78
<arg choice="plain"><option>--port
79
<replaceable>PORT</replaceable></option></arg>
80
<arg choice="plain"><option>-p
81
<replaceable>PORT</replaceable></option></arg>
84
<arg><option>--priority
85
<replaceable>PRIORITY</replaceable></option></arg>
87
<arg><option>--servicename
88
<replaceable>NAME</replaceable></option></arg>
90
<arg><option>--configdir
91
<replaceable>DIRECTORY</replaceable></option></arg>
93
<arg><option>--debug</option></arg>
95
<arg><option>--debuglevel
96
<replaceable>LEVEL</replaceable></option></arg>
98
<arg><option>--no-dbus</option></arg>
100
<arg><option>--no-ipv6</option></arg>
102
<arg><option>--no-restore</option></arg>
104
<arg><option>--statedir
105
<replaceable>DIRECTORY</replaceable></option></arg>
107
<arg><option>--socket
108
<replaceable>FD</replaceable></option></arg>
110
<arg><option>--foreground</option></arg>
112
<arg><option>--no-zeroconf</option></arg>
115
<command>&COMMANDNAME;</command>
117
<arg choice="plain"><option>--help</option></arg>
118
<arg choice="plain"><option>-h</option></arg>
122
<command>&COMMANDNAME;</command>
123
<arg choice="plain"><option>--version</option></arg>
126
<command>&COMMANDNAME;</command>
127
<arg choice="plain"><option>--check</option></arg>
80
131
<refsect1 id="description">
81
132
<title>DESCRIPTION</title>
83
<command>&COMMANDNAME;</command> is a server daemon that handels
84
incomming passwords request for passwords. Mandos use avahi to
85
announce the service, and through gnutls authenticates
86
clients. Any authenticated client is then given its encrypted
92
<term><literal>-h</literal>, <literal>--help</literal></term>
95
show a help message and exit
101
<term><literal>-i</literal>, <literal>--interface <replaceable>
102
IF</replaceable></literal></term>
111
<term><literal>-a</literal>, <literal>--address <replaceable>
112
ADDRESS</replaceable></literal></term>
115
Address to listen for requests on
121
<term><literal>-p</literal>, <literal>--port <replaceable>
122
PORT</replaceable></literal></term>
125
Port number to receive requests on
131
<term><literal>--check</literal></term>
134
Run self-test on the server
140
<term><literal>--debug</literal></term>
149
<term><literal>--priority <replaceable>
150
PRIORITY</replaceable></literal></term>
153
GnuTLS priority string. See <citerefentry>
154
<refentrytitle>gnutls_priority_init</refentrytitle>
155
<manvolnum>3</manvolnum></citerefentry>
161
<term><literal>--servicename <replaceable>NAME</replaceable>
165
Zeroconf service name
171
<term><literal>--configdir <replaceable>DIR</replaceable>
175
Directory to search for configuration files
134
<command>&COMMANDNAME;</command> is a server daemon which
135
handles incoming request for passwords for a pre-defined list of
136
client host computers. For an introduction, see
137
<citerefentry><refentrytitle>intro</refentrytitle>
138
<manvolnum>8mandos</manvolnum></citerefentry>. The Mandos server
139
uses Zeroconf to announce itself on the local network, and uses
140
TLS to communicate securely with and to authenticate the
141
clients. The Mandos server uses IPv6 to allow Mandos clients to
142
use IPv6 link-local addresses, since the clients will probably
143
not have any other addresses configured (see <xref
144
linkend="overview"/>). Any authenticated client is then given
145
the stored pre-encrypted password for that specific client.
149
<refsect1 id="purpose">
150
<title>PURPOSE</title>
152
The purpose of this is to enable <emphasis>remote and unattended
153
rebooting</emphasis> of client host computer with an
154
<emphasis>encrypted root file system</emphasis>. See <xref
155
linkend="overview"/> for details.
159
<refsect1 id="options">
160
<title>OPTIONS</title>
163
<term><option>--help</option></term>
164
<term><option>-h</option></term>
167
Show a help message and exit
173
<term><option>--interface</option>
174
<replaceable>NAME</replaceable></term>
175
<term><option>-i</option>
176
<replaceable>NAME</replaceable></term>
178
<xi:include href="mandos-options.xml" xpointer="interface"/>
183
<term><option>--address
184
<replaceable>ADDRESS</replaceable></option></term>
186
<replaceable>ADDRESS</replaceable></option></term>
188
<xi:include href="mandos-options.xml" xpointer="address"/>
194
<replaceable>PORT</replaceable></option></term>
196
<replaceable>PORT</replaceable></option></term>
198
<xi:include href="mandos-options.xml" xpointer="port"/>
203
<term><option>--check</option></term>
206
Run the server’s self-tests. This includes any unit
213
<term><option>--debug</option></term>
215
<xi:include href="mandos-options.xml" xpointer="debug"/>
220
<term><option>--debuglevel
221
<replaceable>LEVEL</replaceable></option></term>
224
Set the debugging log level.
225
<replaceable>LEVEL</replaceable> is a string, one of
226
<quote><literal>CRITICAL</literal></quote>,
227
<quote><literal>ERROR</literal></quote>,
228
<quote><literal>WARNING</literal></quote>,
229
<quote><literal>INFO</literal></quote>, or
230
<quote><literal>DEBUG</literal></quote>, in order of
231
increasing verbosity. The default level is
232
<quote><literal>WARNING</literal></quote>.
238
<term><option>--priority <replaceable>
239
PRIORITY</replaceable></option></term>
241
<xi:include href="mandos-options.xml" xpointer="priority"/>
246
<term><option>--servicename
247
<replaceable>NAME</replaceable></option></term>
249
<xi:include href="mandos-options.xml"
250
xpointer="servicename"/>
255
<term><option>--configdir
256
<replaceable>DIRECTORY</replaceable></option></term>
259
Directory to search for configuration files. Default is
260
<quote><literal>/etc/mandos</literal></quote>. See
261
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
262
<manvolnum>5</manvolnum></citerefentry> and <citerefentry>
263
<refentrytitle>mandos-clients.conf</refentrytitle>
264
<manvolnum>5</manvolnum></citerefentry>.
270
<term><option>--version</option></term>
273
Prints the program version and exit.
279
<term><option>--no-dbus</option></term>
281
<xi:include href="mandos-options.xml" xpointer="dbus"/>
283
See also <xref linkend="dbus_interface"/>.
289
<term><option>--no-ipv6</option></term>
291
<xi:include href="mandos-options.xml" xpointer="ipv6"/>
296
<term><option>--no-restore</option></term>
298
<xi:include href="mandos-options.xml" xpointer="restore"/>
300
See also <xref linkend="persistent_state"/>.
306
<term><option>--statedir
307
<replaceable>DIRECTORY</replaceable></option></term>
309
<xi:include href="mandos-options.xml" xpointer="statedir"/>
314
<term><option>--socket
315
<replaceable>FD</replaceable></option></term>
317
<xi:include href="mandos-options.xml" xpointer="socket"/>
322
<term><option>--foreground</option></term>
324
<xi:include href="mandos-options.xml"
325
xpointer="foreground"/>
330
<term><option>--no-zeroconf</option></term>
332
<xi:include href="mandos-options.xml" xpointer="zeroconf"/>
339
<refsect1 id="overview">
340
<title>OVERVIEW</title>
341
<xi:include href="overview.xml"/>
343
This program is the server part. It is a normal server program
344
and will run in a normal system environment, not in an initial
345
<acronym>RAM</acronym> disk environment.
349
<refsect1 id="protocol">
350
<title>NETWORK PROTOCOL</title>
352
The Mandos server announces itself as a Zeroconf service of type
353
<quote><literal>_mandos._tcp</literal></quote>. The Mandos
354
client connects to the announced address and port, and sends a
355
line of text where the first whitespace-separated field is the
356
protocol version, which currently is
357
<quote><literal>1</literal></quote>. The client and server then
358
start a TLS protocol handshake with a slight quirk: the Mandos
359
server program acts as a TLS <quote>client</quote> while the
360
connecting Mandos client acts as a TLS <quote>server</quote>.
361
The Mandos client must supply an OpenPGP certificate, and the
362
fingerprint of this certificate is used by the Mandos server to
363
look up (in a list read from <filename>clients.conf</filename>
364
at start time) which binary blob to give the client. No other
365
authentication or authorization is done by the server.
368
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
370
<entry>Mandos Client</entry>
371
<entry>Direction</entry>
372
<entry>Mandos Server</entry>
376
<entry>Connect</entry>
377
<entry>-><!-- → --></entry>
380
<entry><quote><literal>1\r\n</literal></quote></entry>
381
<entry>-><!-- → --></entry>
384
<entry>TLS handshake <emphasis>as TLS <quote>server</quote>
386
<entry><-><!-- ⟷ --></entry>
387
<entry>TLS handshake <emphasis>as TLS <quote>client</quote>
391
<entry>OpenPGP public key (part of TLS handshake)</entry>
392
<entry>-><!-- → --></entry>
396
<entry><-<!-- ← --></entry>
397
<entry>Binary blob (client will assume OpenPGP data)</entry>
401
<entry><-<!-- ← --></entry>
404
</tbody></tgroup></table>
407
<refsect1 id="checking">
408
<title>CHECKING</title>
410
The server will, by default, continually check that the clients
411
are still up. If a client has not been confirmed as being up
412
for some time, the client is assumed to be compromised and is no
413
longer eligible to receive the encrypted password. (Manual
414
intervention is required to re-enable a client.) The timeout,
415
extended timeout, checker program, and interval between checks
416
can be configured both globally and per client; see
417
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
418
<manvolnum>5</manvolnum></citerefentry>.
422
<refsect1 id="approval">
423
<title>APPROVAL</title>
425
The server can be configured to require manual approval for a
426
client before it is sent its secret. The delay to wait for such
427
approval and the default action (approve or deny) can be
428
configured both globally and per client; see <citerefentry>
429
<refentrytitle>mandos-clients.conf</refentrytitle>
430
<manvolnum>5</manvolnum></citerefentry>. By default all clients
431
will be approved immediately without delay.
434
This can be used to deny a client its secret if not manually
435
approved within a specified time. It can also be used to make
436
the server delay before giving a client its secret, allowing
437
optional manual denying of this specific client.
442
<refsect1 id="logging">
443
<title>LOGGING</title>
445
The server will send log message with various severity levels to
446
<filename class="devicefile">/dev/log</filename>. With the
447
<option>--debug</option> option, it will log even more messages,
448
and also show them on the console.
452
<refsect1 id="persistent_state">
453
<title>PERSISTENT STATE</title>
455
Client settings, initially read from
456
<filename>clients.conf</filename>, are persistent across
457
restarts, and run-time changes will override settings in
458
<filename>clients.conf</filename>. However, if a setting is
459
<emphasis>changed</emphasis> (or a client added, or removed) in
460
<filename>clients.conf</filename>, this will take precedence.
464
<refsect1 id="dbus_interface">
465
<title>D-BUS INTERFACE</title>
467
The server will by default provide a D-Bus system bus interface.
468
This interface will only be accessible by the root user or a
469
Mandos-specific user, if such a user exists. For documentation
470
of the D-Bus API, see the file <filename>DBUS-API</filename>.
474
<refsect1 id="exit_status">
475
<title>EXIT STATUS</title>
477
The server will exit with a non-zero exit status only when a
478
critical error is encountered.
482
<refsect1 id="environment">
483
<title>ENVIRONMENT</title>
486
<term><envar>PATH</envar></term>
489
To start the configured checker (see <xref
490
linkend="checking"/>), the server uses
491
<filename>/bin/sh</filename>, which in turn uses
492
<varname>PATH</varname> to search for matching commands if
493
an absolute path is not given. See <citerefentry>
494
<refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum>
502
<refsect1 id="files">
505
Use the <option>--configdir</option> option to change where
506
<command>&COMMANDNAME;</command> looks for its configurations
507
files. The default file names are listed here.
511
<term><filename>/etc/mandos/mandos.conf</filename></term>
514
Server-global settings. See
515
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
516
<manvolnum>5</manvolnum></citerefentry> for details.
521
<term><filename>/etc/mandos/clients.conf</filename></term>
524
List of clients and client-specific settings. See
525
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
526
<manvolnum>5</manvolnum></citerefentry> for details.
531
<term><filename>/run/mandos.pid</filename></term>
534
The file containing the process id of the
535
<command>&COMMANDNAME;</command> process started last.
536
<emphasis >Note:</emphasis> If the <filename
537
class="directory">/run</filename> directory does not
538
exist, <filename>/var/run/mandos.pid</filename> will be
545
class="directory">/var/lib/mandos</filename></term>
548
Directory where persistent state will be saved. Change
549
this with the <option>--statedir</option> option. See
550
also the <option>--no-restore</option> option.
555
<term><filename class="devicefile">/dev/log</filename></term>
558
The Unix domain socket to where local syslog messages are
564
<term><filename>/bin/sh</filename></term>
567
This is used to start the configured checker command for
568
each client. See <citerefentry>
569
<refentrytitle>mandos-clients.conf</refentrytitle>
570
<manvolnum>5</manvolnum></citerefentry> for details.
580
This server might, on especially fatal errors, emit a Python
581
backtrace. This could be considered a feature.
584
There is no fine-grained control over logging and debug output.
587
This server does not check the expire time of clients’ OpenPGP
592
<refsect1 id="example">
593
<title>EXAMPLE</title>
596
Normal invocation needs no options:
599
<userinput>&COMMANDNAME;</userinput>
604
Run the server in debug mode, read configuration files from
605
the <filename class="directory">~/mandos</filename> directory,
606
and use the Zeroconf service name <quote>Test</quote> to not
607
collide with any other official Mandos server on this host:
611
<!-- do not wrap this line -->
612
<userinput>&COMMANDNAME; --debug --configdir ~/mandos --servicename Test</userinput>
618
Run the server normally, but only listen to one interface and
619
only on the link-local address on that interface:
623
<!-- do not wrap this line -->
624
<userinput>&COMMANDNAME; --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>
630
<refsect1 id="security">
631
<title>SECURITY</title>
632
<refsect2 id="server">
633
<title>SERVER</title>
635
Running this <command>&COMMANDNAME;</command> server program
636
should not in itself present any security risk to the host
637
computer running it. The program switches to a non-root user
641
<refsect2 id="clients">
642
<title>CLIENTS</title>
644
The server only gives out its stored data to clients which
645
does have the OpenPGP key of the stored fingerprint. This is
646
guaranteed by the fact that the client sends its OpenPGP
647
public key in the TLS handshake; this ensures it to be
648
genuine. The server computes the fingerprint of the key
649
itself and looks up the fingerprint in its list of
650
clients. The <filename>clients.conf</filename> file (see
651
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
652
<manvolnum>5</manvolnum></citerefentry>)
653
<emphasis>must</emphasis> be made non-readable by anyone
654
except the user starting the server (usually root).
657
As detailed in <xref linkend="checking"/>, the status of all
658
client computers will continually be checked and be assumed
659
compromised if they are gone for too long.
662
For more details on client-side security, see
663
<citerefentry><refentrytitle>mandos-client</refentrytitle>
664
<manvolnum>8mandos</manvolnum></citerefentry>.
669
<refsect1 id="see_also">
670
<title>SEE ALSO</title>
672
<citerefentry><refentrytitle>intro</refentrytitle>
673
<manvolnum>8mandos</manvolnum></citerefentry>,
674
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
675
<manvolnum>5</manvolnum></citerefentry>,
676
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
677
<manvolnum>5</manvolnum></citerefentry>,
678
<citerefentry><refentrytitle>mandos-client</refentrytitle>
679
<manvolnum>8mandos</manvolnum></citerefentry>,
680
<citerefentry><refentrytitle>sh</refentrytitle>
681
<manvolnum>1</manvolnum></citerefentry>
686
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
690
Zeroconf is the network protocol standard used by clients
691
for finding this Mandos server on the local network.
697
<ulink url="http://www.avahi.org/">Avahi</ulink>
701
Avahi is the library this server calls to implement
702
Zeroconf service announcements.
708
<ulink url="http://gnutls.org/">GnuTLS</ulink>
712
GnuTLS is the library this server uses to implement TLS for
713
communicating securely with the client, and at the same time
714
confidently get the client’s public OpenPGP key.
720
RFC 4291: <citetitle>IP Version 6 Addressing
721
Architecture</citetitle>
726
<term>Section 2.2: <citetitle>Text Representation of
727
Addresses</citetitle></term>
728
<listitem><para/></listitem>
731
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
732
Address</citetitle></term>
733
<listitem><para/></listitem>
736
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
737
Addresses</citetitle></term>
740
The clients use IPv6 link-local addresses, which are
741
immediately usable since a link-local addresses is
742
automatically assigned to a network interfaces when it
752
RFC 5246: <citetitle>The Transport Layer Security (TLS)
753
Protocol Version 1.2</citetitle>
757
TLS 1.2 is the protocol implemented by GnuTLS.
763
RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
767
The data sent to clients is binary encrypted OpenPGP data.
773
RFC 6091: <citetitle>Using OpenPGP Keys for Transport Layer
774
Security (TLS) Authentication</citetitle>
778
This is implemented by GnuTLS and used by this server so
779
that OpenPGP keys can be used.
786
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787
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788
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