67
55
<refname><command>&COMMANDNAME;</command></refname>
69
Sends encrypted passwords to authenticated mandos clients
57
Gives encrypted passwords to authenticated Mandos clients
75
63
<command>&COMMANDNAME;</command>
76
<arg choice='opt'>--interface<arg choice='plain'>IF</arg></arg>
77
<arg choice='opt'>--address<arg choice='plain'>ADDRESS</arg></arg>
78
<arg choice='opt'>--port<arg choice='plain'>PORT</arg></arg>
79
<arg choice='opt'>--priority<arg choice='plain'>PRIORITY</arg></arg>
80
<arg choice='opt'>--servicename<arg choice='plain'>NAME</arg></arg>
81
<arg choice='opt'>--configdir<arg choice='plain'>DIRECTORY</arg></arg>
82
<arg choice='opt'>--debug</arg>
85
<command>&COMMANDNAME;</command>
86
<arg choice='plain'>--help</arg>
89
<command>&COMMANDNAME;</command>
90
<arg choice='plain'>--check</arg>
93
<command>&COMMANDNAME;</command>
94
<arg choice='plain'>--version</arg>
65
<arg choice="plain"><option>--interface
66
<replaceable>NAME</replaceable></option></arg>
67
<arg choice="plain"><option>-i
68
<replaceable>NAME</replaceable></option></arg>
72
<arg choice="plain"><option>--address
73
<replaceable>ADDRESS</replaceable></option></arg>
74
<arg choice="plain"><option>-a
75
<replaceable>ADDRESS</replaceable></option></arg>
79
<arg choice="plain"><option>--port
80
<replaceable>PORT</replaceable></option></arg>
81
<arg choice="plain"><option>-p
82
<replaceable>PORT</replaceable></option></arg>
85
<arg><option>--priority
86
<replaceable>PRIORITY</replaceable></option></arg>
88
<arg><option>--servicename
89
<replaceable>NAME</replaceable></option></arg>
91
<arg><option>--configdir
92
<replaceable>DIRECTORY</replaceable></option></arg>
94
<arg><option>--debug</option></arg>
96
<arg><option>--debuglevel
97
<replaceable>LEVEL</replaceable></option></arg>
99
<arg><option>--no-dbus</option></arg>
101
<arg><option>--no-ipv6</option></arg>
103
<arg><option>--no-restore</option></arg>
105
<arg><option>--statedir
106
<replaceable>DIRECTORY</replaceable></option></arg>
108
<arg><option>--socket
109
<replaceable>FD</replaceable></option></arg>
111
<arg><option>--foreground</option></arg>
113
<arg><option>--no-zeroconf</option></arg>
116
<command>&COMMANDNAME;</command>
118
<arg choice="plain"><option>--help</option></arg>
119
<arg choice="plain"><option>-h</option></arg>
123
<command>&COMMANDNAME;</command>
124
<arg choice="plain"><option>--version</option></arg>
127
<command>&COMMANDNAME;</command>
128
<arg choice="plain"><option>--check</option></arg>
98
132
<refsect1 id="description">
99
133
<title>DESCRIPTION</title>
101
<command>&COMMANDNAME;</command> is a server daemon that handels
102
incomming passwords request for passwords. Mandos use avahi to
103
announce the service, and through gnutls authenticates
104
clients. Any authenticated client is then given its encrypted
110
<term><literal>-h</literal>, <literal>--help</literal></term>
113
show a help message and exit
119
<term><literal>-i</literal>, <literal>--interface <replaceable>
120
IF</replaceable></literal></term>
129
<term><literal>-a</literal>, <literal>--address <replaceable>
130
ADDRESS</replaceable></literal></term>
133
Address to listen for requests on
139
<term><literal>-p</literal>, <literal>--port <replaceable>
140
PORT</replaceable></literal></term>
143
Port number to receive requests on
149
<term><literal>--check</literal></term>
152
Run self-test on the server
158
<term><literal>--debug</literal></term>
167
<term><literal>--priority <replaceable>
168
PRIORITY</replaceable></literal></term>
171
GnuTLS priority string. See <citerefentry>
172
<refentrytitle>gnutls_priority_init</refentrytitle>
173
<manvolnum>3</manvolnum></citerefentry>
179
<term><literal>--servicename <replaceable>NAME</replaceable>
183
Zeroconf service name
189
<term><literal>--configdir <replaceable>DIR</replaceable>
193
Directory to search for configuration files
135
<command>&COMMANDNAME;</command> is a server daemon which
136
handles incoming request for passwords for a pre-defined list of
137
client host computers. For an introduction, see
138
<citerefentry><refentrytitle>intro</refentrytitle>
139
<manvolnum>8mandos</manvolnum></citerefentry>. The Mandos server
140
uses Zeroconf to announce itself on the local network, and uses
141
TLS to communicate securely with and to authenticate the
142
clients. The Mandos server uses IPv6 to allow Mandos clients to
143
use IPv6 link-local addresses, since the clients will probably
144
not have any other addresses configured (see <xref
145
linkend="overview"/>). Any authenticated client is then given
146
the stored pre-encrypted password for that specific client.
150
<refsect1 id="purpose">
151
<title>PURPOSE</title>
153
The purpose of this is to enable <emphasis>remote and unattended
154
rebooting</emphasis> of client host computer with an
155
<emphasis>encrypted root file system</emphasis>. See <xref
156
linkend="overview"/> for details.
160
<refsect1 id="options">
161
<title>OPTIONS</title>
164
<term><option>--help</option></term>
165
<term><option>-h</option></term>
168
Show a help message and exit
174
<term><option>--interface</option>
175
<replaceable>NAME</replaceable></term>
176
<term><option>-i</option>
177
<replaceable>NAME</replaceable></term>
179
<xi:include href="mandos-options.xml" xpointer="interface"/>
184
<term><option>--address
185
<replaceable>ADDRESS</replaceable></option></term>
187
<replaceable>ADDRESS</replaceable></option></term>
189
<xi:include href="mandos-options.xml" xpointer="address"/>
195
<replaceable>PORT</replaceable></option></term>
197
<replaceable>PORT</replaceable></option></term>
199
<xi:include href="mandos-options.xml" xpointer="port"/>
204
<term><option>--check</option></term>
207
Run the server’s self-tests. This includes any unit
214
<term><option>--debug</option></term>
216
<xi:include href="mandos-options.xml" xpointer="debug"/>
221
<term><option>--debuglevel
222
<replaceable>LEVEL</replaceable></option></term>
225
Set the debugging log level.
226
<replaceable>LEVEL</replaceable> is a string, one of
227
<quote><literal>CRITICAL</literal></quote>,
228
<quote><literal>ERROR</literal></quote>,
229
<quote><literal>WARNING</literal></quote>,
230
<quote><literal>INFO</literal></quote>, or
231
<quote><literal>DEBUG</literal></quote>, in order of
232
increasing verbosity. The default level is
233
<quote><literal>WARNING</literal></quote>.
239
<term><option>--priority <replaceable>
240
PRIORITY</replaceable></option></term>
242
<xi:include href="mandos-options.xml" xpointer="priority"/>
247
<term><option>--servicename
248
<replaceable>NAME</replaceable></option></term>
250
<xi:include href="mandos-options.xml"
251
xpointer="servicename"/>
256
<term><option>--configdir
257
<replaceable>DIRECTORY</replaceable></option></term>
260
Directory to search for configuration files. Default is
261
<quote><literal>/etc/mandos</literal></quote>. See
262
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
263
<manvolnum>5</manvolnum></citerefentry> and <citerefentry>
264
<refentrytitle>mandos-clients.conf</refentrytitle>
265
<manvolnum>5</manvolnum></citerefentry>.
271
<term><option>--version</option></term>
274
Prints the program version and exit.
280
<term><option>--no-dbus</option></term>
282
<xi:include href="mandos-options.xml" xpointer="dbus"/>
284
See also <xref linkend="dbus_interface"/>.
290
<term><option>--no-ipv6</option></term>
292
<xi:include href="mandos-options.xml" xpointer="ipv6"/>
297
<term><option>--no-restore</option></term>
299
<xi:include href="mandos-options.xml" xpointer="restore"/>
301
See also <xref linkend="persistent_state"/>.
307
<term><option>--statedir
308
<replaceable>DIRECTORY</replaceable></option></term>
310
<xi:include href="mandos-options.xml" xpointer="statedir"/>
315
<term><option>--socket
316
<replaceable>FD</replaceable></option></term>
318
<xi:include href="mandos-options.xml" xpointer="socket"/>
323
<term><option>--foreground</option></term>
325
<xi:include href="mandos-options.xml"
326
xpointer="foreground"/>
331
<term><option>--no-zeroconf</option></term>
333
<xi:include href="mandos-options.xml" xpointer="zeroconf"/>
340
<refsect1 id="overview">
341
<title>OVERVIEW</title>
342
<xi:include href="overview.xml"/>
344
This program is the server part. It is a normal server program
345
and will run in a normal system environment, not in an initial
346
<acronym>RAM</acronym> disk environment.
350
<refsect1 id="protocol">
351
<title>NETWORK PROTOCOL</title>
353
The Mandos server announces itself as a Zeroconf service of type
354
<quote><literal>_mandos._tcp</literal></quote>. The Mandos
355
client connects to the announced address and port, and sends a
356
line of text where the first whitespace-separated field is the
357
protocol version, which currently is
358
<quote><literal>1</literal></quote>. The client and server then
359
start a TLS protocol handshake with a slight quirk: the Mandos
360
server program acts as a TLS <quote>client</quote> while the
361
connecting Mandos client acts as a TLS <quote>server</quote>.
362
The Mandos client must supply an OpenPGP certificate, and the
363
fingerprint of this certificate is used by the Mandos server to
364
look up (in a list read from <filename>clients.conf</filename>
365
at start time) which binary blob to give the client. No other
366
authentication or authorization is done by the server.
369
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
371
<entry>Mandos Client</entry>
372
<entry>Direction</entry>
373
<entry>Mandos Server</entry>
377
<entry>Connect</entry>
378
<entry>-><!-- → --></entry>
381
<entry><quote><literal>1\r\n</literal></quote></entry>
382
<entry>-><!-- → --></entry>
385
<entry>TLS handshake <emphasis>as TLS <quote>server</quote>
387
<entry><-><!-- ⟷ --></entry>
388
<entry>TLS handshake <emphasis>as TLS <quote>client</quote>
392
<entry>OpenPGP public key (part of TLS handshake)</entry>
393
<entry>-><!-- → --></entry>
397
<entry><-<!-- ← --></entry>
398
<entry>Binary blob (client will assume OpenPGP data)</entry>
402
<entry><-<!-- ← --></entry>
405
</tbody></tgroup></table>
408
<refsect1 id="checking">
409
<title>CHECKING</title>
411
The server will, by default, continually check that the clients
412
are still up. If a client has not been confirmed as being up
413
for some time, the client is assumed to be compromised and is no
414
longer eligible to receive the encrypted password. (Manual
415
intervention is required to re-enable a client.) The timeout,
416
extended timeout, checker program, and interval between checks
417
can be configured both globally and per client; see
418
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
419
<manvolnum>5</manvolnum></citerefentry>.
423
<refsect1 id="approval">
424
<title>APPROVAL</title>
426
The server can be configured to require manual approval for a
427
client before it is sent its secret. The delay to wait for such
428
approval and the default action (approve or deny) can be
429
configured both globally and per client; see <citerefentry>
430
<refentrytitle>mandos-clients.conf</refentrytitle>
431
<manvolnum>5</manvolnum></citerefentry>. By default all clients
432
will be approved immediately without delay.
435
This can be used to deny a client its secret if not manually
436
approved within a specified time. It can also be used to make
437
the server delay before giving a client its secret, allowing
438
optional manual denying of this specific client.
443
<refsect1 id="logging">
444
<title>LOGGING</title>
446
The server will send log message with various severity levels to
447
<filename class="devicefile">/dev/log</filename>. With the
448
<option>--debug</option> option, it will log even more messages,
449
and also show them on the console.
453
<refsect1 id="persistent_state">
454
<title>PERSISTENT STATE</title>
456
Client settings, initially read from
457
<filename>clients.conf</filename>, are persistent across
458
restarts, and run-time changes will override settings in
459
<filename>clients.conf</filename>. However, if a setting is
460
<emphasis>changed</emphasis> (or a client added, or removed) in
461
<filename>clients.conf</filename>, this will take precedence.
465
<refsect1 id="dbus_interface">
466
<title>D-BUS INTERFACE</title>
468
The server will by default provide a D-Bus system bus interface.
469
This interface will only be accessible by the root user or a
470
Mandos-specific user, if such a user exists. For documentation
471
of the D-Bus API, see the file <filename>DBUS-API</filename>.
475
<refsect1 id="exit_status">
476
<title>EXIT STATUS</title>
478
The server will exit with a non-zero exit status only when a
479
critical error is encountered.
483
<refsect1 id="environment">
484
<title>ENVIRONMENT</title>
487
<term><envar>PATH</envar></term>
490
To start the configured checker (see <xref
491
linkend="checking"/>), the server uses
492
<filename>/bin/sh</filename>, which in turn uses
493
<varname>PATH</varname> to search for matching commands if
494
an absolute path is not given. See <citerefentry>
495
<refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum>
503
<refsect1 id="files">
506
Use the <option>--configdir</option> option to change where
507
<command>&COMMANDNAME;</command> looks for its configurations
508
files. The default file names are listed here.
512
<term><filename>/etc/mandos/mandos.conf</filename></term>
515
Server-global settings. See
516
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
517
<manvolnum>5</manvolnum></citerefentry> for details.
522
<term><filename>/etc/mandos/clients.conf</filename></term>
525
List of clients and client-specific settings. See
526
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
527
<manvolnum>5</manvolnum></citerefentry> for details.
532
<term><filename>/run/mandos.pid</filename></term>
535
The file containing the process id of the
536
<command>&COMMANDNAME;</command> process started last.
537
<emphasis >Note:</emphasis> If the <filename
538
class="directory">/run</filename> directory does not
539
exist, <filename>/var/run/mandos.pid</filename> will be
546
class="directory">/var/lib/mandos</filename></term>
549
Directory where persistent state will be saved. Change
550
this with the <option>--statedir</option> option. See
551
also the <option>--no-restore</option> option.
556
<term><filename class="devicefile">/dev/log</filename></term>
559
The Unix domain socket to where local syslog messages are
565
<term><filename>/bin/sh</filename></term>
568
This is used to start the configured checker command for
569
each client. See <citerefentry>
570
<refentrytitle>mandos-clients.conf</refentrytitle>
571
<manvolnum>5</manvolnum></citerefentry> for details.
581
This server might, on especially fatal errors, emit a Python
582
backtrace. This could be considered a feature.
585
There is no fine-grained control over logging and debug output.
588
This server does not check the expire time of clients’ OpenPGP
591
<xi:include href="bugs.xml"/>
594
<refsect1 id="example">
595
<title>EXAMPLE</title>
598
Normal invocation needs no options:
601
<userinput>&COMMANDNAME;</userinput>
606
Run the server in debug mode, read configuration files from
607
the <filename class="directory">~/mandos</filename> directory,
608
and use the Zeroconf service name <quote>Test</quote> to not
609
collide with any other official Mandos server on this host:
613
<!-- do not wrap this line -->
614
<userinput>&COMMANDNAME; --debug --configdir ~/mandos --servicename Test</userinput>
620
Run the server normally, but only listen to one interface and
621
only on the link-local address on that interface:
625
<!-- do not wrap this line -->
626
<userinput>&COMMANDNAME; --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>
632
<refsect1 id="security">
633
<title>SECURITY</title>
634
<refsect2 id="server">
635
<title>SERVER</title>
637
Running this <command>&COMMANDNAME;</command> server program
638
should not in itself present any security risk to the host
639
computer running it. The program switches to a non-root user
643
<refsect2 id="clients">
644
<title>CLIENTS</title>
646
The server only gives out its stored data to clients which
647
does have the OpenPGP key of the stored fingerprint. This is
648
guaranteed by the fact that the client sends its OpenPGP
649
public key in the TLS handshake; this ensures it to be
650
genuine. The server computes the fingerprint of the key
651
itself and looks up the fingerprint in its list of
652
clients. The <filename>clients.conf</filename> file (see
653
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
654
<manvolnum>5</manvolnum></citerefentry>)
655
<emphasis>must</emphasis> be made non-readable by anyone
656
except the user starting the server (usually root).
659
As detailed in <xref linkend="checking"/>, the status of all
660
client computers will continually be checked and be assumed
661
compromised if they are gone for too long.
664
For more details on client-side security, see
665
<citerefentry><refentrytitle>mandos-client</refentrytitle>
666
<manvolnum>8mandos</manvolnum></citerefentry>.
671
<refsect1 id="see_also">
672
<title>SEE ALSO</title>
674
<citerefentry><refentrytitle>intro</refentrytitle>
675
<manvolnum>8mandos</manvolnum></citerefentry>,
676
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
677
<manvolnum>5</manvolnum></citerefentry>,
678
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
679
<manvolnum>5</manvolnum></citerefentry>,
680
<citerefentry><refentrytitle>mandos-client</refentrytitle>
681
<manvolnum>8mandos</manvolnum></citerefentry>,
682
<citerefentry><refentrytitle>sh</refentrytitle>
683
<manvolnum>1</manvolnum></citerefentry>
688
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
692
Zeroconf is the network protocol standard used by clients
693
for finding this Mandos server on the local network.
699
<ulink url="http://www.avahi.org/">Avahi</ulink>
703
Avahi is the library this server calls to implement
704
Zeroconf service announcements.
710
<ulink url="http://gnutls.org/">GnuTLS</ulink>
714
GnuTLS is the library this server uses to implement TLS for
715
communicating securely with the client, and at the same time
716
confidently get the client’s public OpenPGP key.
722
RFC 4291: <citetitle>IP Version 6 Addressing
723
Architecture</citetitle>
728
<term>Section 2.2: <citetitle>Text Representation of
729
Addresses</citetitle></term>
730
<listitem><para/></listitem>
733
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
734
Address</citetitle></term>
735
<listitem><para/></listitem>
738
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
739
Addresses</citetitle></term>
742
The clients use IPv6 link-local addresses, which are
743
immediately usable since a link-local addresses is
744
automatically assigned to a network interfaces when it
754
RFC 5246: <citetitle>The Transport Layer Security (TLS)
755
Protocol Version 1.2</citetitle>
759
TLS 1.2 is the protocol implemented by GnuTLS.
765
RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
769
The data sent to clients is binary encrypted OpenPGP data.
775
RFC 6091: <citetitle>Using OpenPGP Keys for Transport Layer
776
Security (TLS) Authentication</citetitle>
780
This is implemented by GnuTLS and used by this server so
781
that OpenPGP keys can be used.
788
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