67
50
<refname><command>&COMMANDNAME;</command></refname>
69
Sends encrypted passwords to authenticated mandos clients
52
Gives encrypted passwords to authenticated Mandos clients
75
58
<command>&COMMANDNAME;</command>
76
<arg choice='opt' rep='repeat'>OPTION</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>
80
120
<refsect1 id="description">
81
121
<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
123
<command>&COMMANDNAME;</command> is a server daemon which
124
handles incoming request for passwords for a pre-defined list of
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.
138
<refsect1 id="purpose">
139
<title>PURPOSE</title>
141
The purpose of this is to enable <emphasis>remote and unattended
142
rebooting</emphasis> of client host computer with an
143
<emphasis>encrypted root file system</emphasis>. See <xref
144
linkend="overview"/> for details.
148
<refsect1 id="options">
149
<title>OPTIONS</title>
152
<term><option>--help</option></term>
153
<term><option>-h</option></term>
156
Show a help message and exit
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
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>
248
Directory to search for configuration files. Default is
249
<quote><literal>/etc/mandos</literal></quote>. See
250
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
251
<manvolnum>5</manvolnum></citerefentry> and <citerefentry>
252
<refentrytitle>mandos-clients.conf</refentrytitle>
253
<manvolnum>5</manvolnum></citerefentry>.
259
<term><option>--version</option></term>
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.
311
<refsect1 id="protocol">
312
<title>NETWORK PROTOCOL</title>
314
The Mandos server announces itself as a Zeroconf service of type
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.
330
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
332
<entry>Mandos Client</entry>
333
<entry>Direction</entry>
334
<entry>Mandos Server</entry>
338
<entry>Connect</entry>
339
<entry>-><!-- → --></entry>
342
<entry><quote><literal>1\r\n</literal></quote></entry>
343
<entry>-><!-- → --></entry>
346
<entry>TLS handshake <emphasis>as TLS <quote>server</quote>
348
<entry><-><!-- ⟷ --></entry>
349
<entry>TLS handshake <emphasis>as TLS <quote>client</quote>
353
<entry>OpenPGP public key (part of TLS handshake)</entry>
354
<entry>-><!-- → --></entry>
358
<entry><-<!-- ← --></entry>
359
<entry>Binary blob (client will assume OpenPGP data)</entry>
363
<entry><-<!-- ← --></entry>
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.
406
<refsect1 id="logging">
407
<title>LOGGING</title>
409
The server will send log message with various severity levels to
410
<filename class="devicefile">/dev/log</filename>. With the
411
<option>--debug</option> option, it will log even more messages,
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>.
426
<refsect1 id="exit_status">
427
<title>EXIT STATUS</title>
429
The server will exit with a non-zero exit status only when a
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">
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>
520
<refentrytitle>mandos-clients.conf</refentrytitle>
521
<manvolnum>5</manvolnum></citerefentry> for details.
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>
584
<refsect1 id="security">
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>.
623
<refsect1 id="see_also">
624
<title>SEE ALSO</title>
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
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