67
67
<refname><command>&COMMANDNAME;</command></refname>
69
Sends encrypted passwords to authenticated Mandos clients
69
Sends encrypted passwords to authenticated mandos clients
75
75
<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>
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<arg choice="opt">--configdir<arg choice="plain">DIRECTORY</arg></arg>
82
<arg choice="opt">--debug</arg>
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<command>&COMMANDNAME;</command>
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<arg choice="opt">-i<arg choice="plain">IF</arg></arg>
87
<arg choice="opt">-a<arg choice="plain">ADDRESS</arg></arg>
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<arg choice="opt">-p<arg choice="plain">PORT</arg></arg>
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<arg choice="opt">--priority<arg choice="plain">PRIORITY</arg></arg>
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<arg choice="opt">--servicename<arg choice="plain">NAME</arg></arg>
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<arg choice="opt">--configdir<arg choice="plain">DIRECTORY</arg></arg>
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<arg choice="opt">--debug</arg>
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<command>&COMMANDNAME;</command>
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<arg choice="plain">--help</arg>
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<command>&COMMANDNAME;</command>
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<arg choice="plain">--version</arg>
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<command>&COMMANDNAME;</command>
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<arg choice="plain">--check</arg>
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<arg choice='opt'>--interface<arg choice='plain'>IF</arg></arg>
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<arg choice='opt'>--address<arg choice='plain'>ADDRESS</arg></arg>
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<arg choice='opt'>--port<arg choice='plain'>PORT</arg></arg>
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<arg choice='opt'>--priority<arg choice='plain'>PRIORITY</arg></arg>
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<arg choice='opt'>--servicename<arg choice='plain'>NAME</arg></arg>
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<arg choice='opt'>--configdir<arg choice='plain'>DIRECTORY</arg></arg>
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<arg choice='opt'>--debug</arg>
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<command>&COMMANDNAME;</command>
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<arg choice='plain'>--help</arg>
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<command>&COMMANDNAME;</command>
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<arg choice='plain'>--check</arg>
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<command>&COMMANDNAME;</command>
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<arg choice='plain'>--version</arg>
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98
<refsect1 id="description">
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99
<title>DESCRIPTION</title>
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<command>&COMMANDNAME;</command> is a server daemon which
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handles incoming request for passwords for a pre-defined list of
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client host computers. The Mandos server uses Zeroconf to
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announce itself on the local network, and uses TLS to
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communicate securely with and to authenticate the clients. The
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Mandos server uses IPv6 to allow Mandos clients to use IPv6
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link-local addresses, since the clients will probably not have
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any other addresses configured (see <xref linkend="overview"/>).
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Any authenticated client is then given the stored pre-encrypted
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password for that specific client.
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<refsect1 id="purpose">
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<title>PURPOSE</title>
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The purpose of this is to enable <emphasis>remote and unattended
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rebooting</emphasis> of client host computer with an
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<emphasis>encrypted root file system</emphasis>. See <xref
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linkend="overview"/> for details.
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<refsect1 id="options">
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<title>OPTIONS</title>
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<command>&COMMANDNAME;</command> is a server daemon that handels
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incomming passwords request for passwords. Mandos use avahi to
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announce the service, and through gnutls authenticates
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clients. Any authenticated client is then given its encrypted
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<term><literal>-h</literal>, <literal>--help</literal></term>
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Show a help message and exit
113
show a help message and exit
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168
PRIORITY</replaceable></literal></term>
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GnuTLS priority string for the TLS handshake with the
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clients. The default is
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<quote><literal>SECURE256:!CTYPE-X.509:+CTYPE-OPENPGP</literal></quote>.
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See <citerefentry><refentrytitle>gnutls_priority_init
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</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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for the syntax. <emphasis>Warning</emphasis>: changing
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this may make the TLS handshake fail, making communication
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with clients impossible.
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GnuTLS priority string. See <citerefentry>
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<refentrytitle>gnutls_priority_init</refentrytitle>
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<manvolnum>3</manvolnum></citerefentry>
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<term><literal>--servicename <replaceable>NAME</replaceable>
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180
</literal></term>
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Zeroconf service name. The default is
235
<quote><literal>Mandos</literal></quote>. You only need
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to change this if you for some reason want to run more
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than one server on the same <emphasis>host</emphasis>,
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which would not normally be useful. If there are name
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collisions on the same <emphasis>network</emphasis>, the
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newer server will automatically rename itself to
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<quote><literal>Mandos #2</literal></quote>, and so on;
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therefore, this option is not needed in that case.
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Zeroconf service name
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<term><literal>--configdir <replaceable>DIR</replaceable>
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190
</literal></term>
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Directory to search for configuration files. Default is
253
<quote><literal>/etc/mandos</literal></quote>. See
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<citerefentry><refentrytitle>mandos.conf</refentrytitle>
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<manvolnum>5</manvolnum></citerefentry> and <citerefentry>
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<refentrytitle>mandos-clients.conf</refentrytitle>
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<manvolnum>5</manvolnum></citerefentry>.
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<term><literal>--version</literal></term>
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Prints the program version and exit.
273
<refsect1 id="overview">
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<title>OVERVIEW</title>
277
This program is the server part. It is a normal server program
278
and will run in a normal system environment, not in an initial
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RAM disk environment.
283
<refsect1 id="protocol">
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<title>NETWORK PROTOCOL</title>
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The Mandos server announces itself as a Zeroconf service of type
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<quote><literal>_mandos._tcp</literal></quote>. The Mandos
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client connects to the announced address and port, and sends a
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line of text where the first whitespace-separated field is the
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protocol version, which currently is
291
<quote><literal>1</literal></quote>. The client and server then
292
start a TLS protocol handshake with a slight quirk: the Mandos
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server program acts as a TLS <quote>client</quote> while the
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connecting Mandos client acts as a TLS <quote>server</quote>.
295
The Mandos client must supply an OpenPGP certificate, and the
296
fingerprint of this certificate is used by the Mandos server to
297
look up (in a list read from <filename>clients.conf</filename>
298
at start time) which binary blob to give the client. No other
299
authentication or authorization is done by the server.
302
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
304
<entry>Mandos Client</entry>
305
<entry>Direction</entry>
306
<entry>Mandos Server</entry>
310
<entry>Connect</entry>
311
<entry>-><!-- → --></entry>
314
<entry><quote><literal>1\r\en</literal></quote></entry>
315
<entry>-><!-- → --></entry>
318
<entry>TLS handshake <emphasis>as TLS <quote>server</quote>
320
<entry><-><!-- ⟷ --></entry>
321
<entry>TLS handshake <emphasis>as TLS <quote>client</quote>
325
<entry>OpenPGP public key (part of TLS handshake)</entry>
326
<entry>-><!-- → --></entry>
330
<entry><-<!-- ← --></entry>
331
<entry>Binary blob (client will assume OpenPGP data)</entry>
335
<entry><-<!-- ← --></entry>
338
</tbody></tgroup></table>
341
<refsect1 id="checking">
342
<title>CHECKING</title>
344
The server will, by default, continually check that the clients
345
are still up. If a client has not been confirmed as being up
346
for some time, the client is assumed to be compromised and is no
347
longer eligible to receive the encrypted password. The timeout,
348
checker program, and interval between checks can be configured
349
both globally and per client; see <citerefentry>
350
<refentrytitle>mandos.conf</refentrytitle>
351
<manvolnum>5</manvolnum></citerefentry> and <citerefentry>
352
<refentrytitle>mandos-clients.conf</refentrytitle>
353
<manvolnum>5</manvolnum></citerefentry>.
357
<refsect1 id="logging">
358
<title>LOGGING</title>
360
The server will send log messaged with various severity levels
361
to <filename>/dev/log</filename>. With the
362
<option>--debug</option> option, it will log even more messages,
363
and also show them on the console.
367
<refsect1 id="exit_status">
368
<title>EXIT STATUS</title>
370
The server will exit with a non-zero exit status only when a
371
critical error is encountered.
378
Use the <option>--configdir</option> option to change where
379
<command>&COMMANDNAME;</command> looks for its configurations
380
files. The default file names are listed here.
384
<term><filename>/etc/mandos/mandos.conf</filename></term>
387
Server-global settings. See
388
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
389
<manvolnum>5</manvolnum></citerefentry> for details.
394
<term><filename>/etc/mandos/clients.conf</filename></term>
397
List of clients and client-specific settings. See
398
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
399
<manvolnum>5</manvolnum></citerefentry> for details.
404
<term><filename>/var/run/mandos/mandos.pid</filename></term>
407
The file containing the process id of
408
<command>&COMMANDNAME;</command>.
413
<term><filename>/dev/log</filename></term>
416
The Unix domain socket to where local syslog messages are
427
This server might, on especially fatal errors, emit a Python
428
backtrace. This could be considered a feature.
432
<refsect1 id="examples">
433
<title>EXAMPLES</title>
436
Normal invocation needs no options:
439
<userinput>mandos</userinput>
444
Run the server in debug mode, read configuration files from
445
the <filename>~/mandos</filename> directory, and use the
446
Zeroconf service name <quote>Test</quote> to not collide with
447
any other official Mandos server on this host:
451
<!-- do not wrap this line -->
452
<userinput>mandos --debug --configdir ~/mandos --servicename Test</userinput>
458
Run the server normally, but only listen to one interface and
459
only on the link-local address on that interface:
463
<!-- do not wrap this line -->
464
<userinput>mandos --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>
470
<refsect1 id="security">
471
<title>SECURITY</title>
473
<title>SERVER</title>
475
Running this &COMMANDNAME; server program should not in itself
476
present any security risk to the host computer running it.
477
The program does not need any special privileges to run, and
478
is designed to run as a non-root user.
482
<title>CLIENTS</title>
484
The server only gives out its stored data to clients which
485
does have the OpenPGP key of the stored fingerprint. This is
486
guaranteed by the fact that the client sends its OpenPGP
487
public key in the TLS handshake; this ensures it to be
488
genuine. The server computes the fingerprint of the key
489
itself and looks up the fingerprint in its list of
490
clients. The <filename>clients.conf</filename> file (see
491
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
492
<manvolnum>5</manvolnum></citerefentry>)
493
<emphasis>must</emphasis> be made non-readable by anyone
494
except the user running the server.
497
As detailed in <xref linkend="checking"/>, the status of all
498
client computers will continually be checked and be assumed
499
compromised if they are gone for too long.
502
For more details on client-side security, see
503
<citerefentry><refentrytitle>password-request</refentrytitle>
504
<manvolnum>8mandos</manvolnum></citerefentry>.
509
<refsect1 id="see_also">
510
<title>SEE ALSO</title>
515
<refentrytitle>password-request</refentrytitle>
516
<manvolnum>8mandos</manvolnum>
521
This is the actual program which talks to this server.
522
Note that it is normally not invoked directly, and is only
523
run in the initial RAM disk environment, and not on a
524
fully started system.
530
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
534
Zeroconf is the network protocol standard used by clients
535
for finding this Mandos server on the local network.
541
<ulink url="http://www.avahi.org/">Avahi</ulink>
545
Avahi is the library this server calls to implement
546
Zeroconf service announcements.
553
url="http://www.gnu.org/software/gnutls/">GnuTLS</ulink>
557
GnuTLS is the library this server uses to implement TLS for
558
communicating securely with the client, and at the same time
559
confidently get the client’s public OpenPGP key.
565
<citation>RFC 4291: <citetitle>IP Version 6 Addressing
566
Architecture</citetitle>, section 2.5.6, Link-Local IPv6
567
Unicast Addresses</citation>
571
The clients use IPv6 link-local addresses, which are
572
immediately usable since a link-local addresses is
573
automatically assigned to a network interfaces when it is
580
<citation>RFC 4346: <citetitle>The Transport Layer Security
581
(TLS) Protocol Version 1.1</citetitle></citation>
585
TLS 1.1 is the protocol implemented by GnuTLS.
591
<citation>RFC 4880: <citetitle>OpenPGP Message
592
Format</citetitle></citation>
596
The data sent to clients is binary encrypted OpenPGP data.
602
<citation>RFC 5081: <citetitle>Using OpenPGP Keys for
603
Transport Layer Security</citetitle></citation>
607
This is implemented by GnuTLS and used by this server so
608
that OpenPGP keys can be used.
193
Directory to search for configuration files