2
2
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
3
3
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
4
4
<!ENTITY COMMANDNAME "mandos">
5
<!ENTITY TIMESTAMP "2010-09-26">
5
<!ENTITY TIMESTAMP "2022-04-24">
6
6
<!ENTITY % common SYSTEM "common.ent">
19
19
<firstname>Björn</firstname>
20
20
<surname>Påhlsson</surname>
22
<email>belorn@fukt.bsnet.se</email>
22
<email>belorn@recompile.se</email>
26
26
<firstname>Teddy</firstname>
27
27
<surname>Hogeborn</surname>
29
<email>teddy@fukt.bsnet.se</email>
29
<email>teddy@recompile.se</email>
93
102
<arg><option>--no-dbus</option></arg>
95
104
<arg><option>--no-ipv6</option></arg>
106
<arg><option>--no-restore</option></arg>
108
<arg><option>--statedir
109
<replaceable>DIRECTORY</replaceable></option></arg>
111
<arg><option>--socket
112
<replaceable>FD</replaceable></option></arg>
114
<arg><option>--foreground</option></arg>
116
<arg><option>--no-zeroconf</option></arg>
98
119
<command>&COMMANDNAME;</command>
115
136
<title>DESCRIPTION</title>
117
138
<command>&COMMANDNAME;</command> is a server daemon which
118
handles incoming request for passwords for a pre-defined list of
119
client host computers. The Mandos server uses Zeroconf to
120
announce itself on the local network, and uses TLS to
121
communicate securely with and to authenticate the clients. The
122
Mandos server uses IPv6 to allow Mandos clients to use IPv6
123
link-local addresses, since the clients will probably not have
124
any other addresses configured (see <xref linkend="overview"/>).
125
Any authenticated client is then given the stored pre-encrypted
126
password for that specific client.
139
handles incoming requests for passwords for a pre-defined list
140
of client host computers. For an introduction, see
141
<citerefentry><refentrytitle>intro</refentrytitle>
142
<manvolnum>8mandos</manvolnum></citerefentry>. The Mandos server
143
uses Zeroconf to announce itself on the local network, and uses
144
TLS to communicate securely with and to authenticate the
145
clients. The Mandos server uses IPv6 to allow Mandos clients to
146
use IPv6 link-local addresses, since the clients will probably
147
not have any other addresses configured (see <xref
148
linkend="overview"/>). Any authenticated client is then given
149
the stored pre-encrypted password for that specific client.
272
295
<xi:include href="mandos-options.xml" xpointer="ipv6"/>
300
<term><option>--no-restore</option></term>
302
<xi:include href="mandos-options.xml" xpointer="restore"/>
304
See also <xref linkend="persistent_state"/>.
310
<term><option>--statedir
311
<replaceable>DIRECTORY</replaceable></option></term>
313
<xi:include href="mandos-options.xml" xpointer="statedir"/>
318
<term><option>--socket
319
<replaceable>FD</replaceable></option></term>
321
<xi:include href="mandos-options.xml" xpointer="socket"/>
326
<term><option>--foreground</option></term>
328
<xi:include href="mandos-options.xml"
329
xpointer="foreground"/>
334
<term><option>--no-zeroconf</option></term>
336
<xi:include href="mandos-options.xml" xpointer="zeroconf"/>
297
362
start a TLS protocol handshake with a slight quirk: the Mandos
298
363
server program acts as a TLS <quote>client</quote> while the
299
364
connecting Mandos client acts as a TLS <quote>server</quote>.
300
The Mandos client must supply an OpenPGP certificate, and the
301
fingerprint of this certificate is used by the Mandos server to
302
look up (in a list read from <filename>clients.conf</filename>
303
at start time) which binary blob to give the client. No other
304
authentication or authorization is done by the server.
365
The Mandos client must supply a TLS public key, and the key ID
366
of this public key is used by the Mandos server to look up (in a
367
list read from <filename>clients.conf</filename> at start time)
368
which binary blob to give the client. No other authentication
369
or authorization is done by the server.
307
372
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
351
416
for some time, the client is assumed to be compromised and is no
352
417
longer eligible to receive the encrypted password. (Manual
353
418
intervention is required to re-enable a client.) The timeout,
354
checker program, and interval between checks can be configured
355
both globally and per client; see <citerefentry>
356
<refentrytitle>mandos-clients.conf</refentrytitle>
357
<manvolnum>5</manvolnum></citerefentry>. A client successfully
358
receiving its password will also be treated as a successful
419
extended timeout, checker program, and interval between checks
420
can be configured both globally and per client; see
421
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
422
<manvolnum>5</manvolnum></citerefentry>.
384
447
<title>LOGGING</title>
386
449
The server will send log message with various severity levels to
387
<filename>/dev/log</filename>. With the
450
<filename class="devicefile">/dev/log</filename>. With the
388
451
<option>--debug</option> option, it will log even more messages,
389
452
and also show them on the console.
456
<refsect1 id="persistent_state">
457
<title>PERSISTENT STATE</title>
459
Client settings, initially read from
460
<filename>clients.conf</filename>, are persistent across
461
restarts, and run-time changes will override settings in
462
<filename>clients.conf</filename>. However, if a setting is
463
<emphasis>changed</emphasis> (or a client added, or removed) in
464
<filename>clients.conf</filename>, this will take precedence.
393
468
<refsect1 id="dbus_interface">
394
469
<title>D-BUS INTERFACE</title>
460
<term><filename>/var/run/mandos.pid</filename></term>
535
<term><filename>/run/mandos.pid</filename></term>
463
538
The file containing the process id of the
464
539
<command>&COMMANDNAME;</command> process started last.
469
<term><filename>/dev/log</filename></term>
540
<emphasis >Note:</emphasis> If the <filename
541
class="directory">/run</filename> directory does not
542
exist, <filename>/var/run/mandos.pid</filename> will be
549
class="directory">/var/lib/mandos</filename></term>
552
Directory where persistent state will be saved. Change
553
this with the <option>--statedir</option> option. See
554
also the <option>--no-restore</option> option.
559
<term><filename class="devicefile">/dev/log</filename></term>
472
562
The Unix domain socket to where local syslog messages are
495
585
backtrace. This could be considered a feature.
498
Currently, if a client is disabled due to having timed out, the
499
server does not record this fact onto permanent storage. This
500
has some security implications, see <xref linkend="clients"/>.
503
588
There is no fine-grained control over logging and debug output.
506
Debug mode is conflated with running in the foreground.
509
The console log messages do not show a time stamp.
512
This server does not check the expire time of clients’ OpenPGP
590
<xi:include href="bugs.xml"/>
517
593
<refsect1 id="example">
527
603
<informalexample>
529
605
Run the server in debug mode, read configuration files from
530
the <filename>~/mandos</filename> directory, and use the
531
Zeroconf service name <quote>Test</quote> to not collide with
532
any other official Mandos server on this host:
606
the <filename class="directory">~/mandos</filename> directory,
607
and use the Zeroconf service name <quote>Test</quote> to not
608
collide with any other official Mandos server on this host:
567
643
<title>CLIENTS</title>
569
645
The server only gives out its stored data to clients which
570
does have the OpenPGP key of the stored fingerprint. This is
571
guaranteed by the fact that the client sends its OpenPGP
572
public key in the TLS handshake; this ensures it to be
573
genuine. The server computes the fingerprint of the key
574
itself and looks up the fingerprint in its list of
575
clients. The <filename>clients.conf</filename> file (see
646
does have the correct key ID of the stored key ID. This is
647
guaranteed by the fact that the client sends its public key in
648
the TLS handshake; this ensures it to be genuine. The server
649
computes the key ID of the key itself and looks up the key ID
650
in its list of clients. The <filename>clients.conf</filename>
576
652
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
577
653
<manvolnum>5</manvolnum></citerefentry>)
578
654
<emphasis>must</emphasis> be made non-readable by anyone
584
660
compromised if they are gone for too long.
587
If a client is compromised, its downtime should be duly noted
588
by the server which would therefore disable the client. But
589
if the server was ever restarted, it would re-read its client
590
list from its configuration file and again regard all clients
591
therein as enabled, and hence eligible to receive their
592
passwords. Therefore, be careful when restarting servers if
593
it is suspected that a client has, in fact, been compromised
594
by parties who may now be running a fake Mandos client with
595
the keys from the non-encrypted initial <acronym>RAM</acronym>
596
image of the client host. What should be done in that case
597
(if restarting the server program really is necessary) is to
598
stop the server program, edit the configuration file to omit
599
any suspect clients, and restart the server program.
602
663
For more details on client-side security, see
603
664
<citerefentry><refentrytitle>mandos-client</refentrytitle>
604
665
<manvolnum>8mandos</manvolnum></citerefentry>.
609
670
<refsect1 id="see_also">
610
671
<title>SEE ALSO</title>
613
<refentrytitle>mandos-clients.conf</refentrytitle>
614
<manvolnum>5</manvolnum></citerefentry>, <citerefentry>
615
<refentrytitle>mandos.conf</refentrytitle>
616
<manvolnum>5</manvolnum></citerefentry>, <citerefentry>
617
<refentrytitle>mandos-client</refentrytitle>
618
<manvolnum>8mandos</manvolnum></citerefentry>, <citerefentry>
619
<refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum>
673
<citerefentry><refentrytitle>intro</refentrytitle>
674
<manvolnum>8mandos</manvolnum></citerefentry>,
675
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
676
<manvolnum>5</manvolnum></citerefentry>,
677
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
678
<manvolnum>5</manvolnum></citerefentry>,
679
<citerefentry><refentrytitle>mandos-client</refentrytitle>
680
<manvolnum>8mandos</manvolnum></citerefentry>,
681
<citerefentry><refentrytitle>sh</refentrytitle>
682
<manvolnum>1</manvolnum></citerefentry>
647
<ulink url="http://www.gnu.org/software/gnutls/"
709
<ulink url="https://gnutls.org/">GnuTLS</ulink>
652
713
GnuTLS is the library this server uses to implement TLS for
653
714
communicating securely with the client, and at the same time
654
confidently get the client’s public OpenPGP key.
715
confidently get the client’s public key.
680
741
The clients use IPv6 link-local addresses, which are
681
immediately usable since a link-local addresses is
742
immediately usable since a link-local address is
682
743
automatically assigned to a network interfaces when it
692
RFC 4346: <citetitle>The Transport Layer Security (TLS)
693
Protocol Version 1.1</citetitle>
753
RFC 5246: <citetitle>The Transport Layer Security (TLS)
754
Protocol Version 1.2</citetitle>
697
TLS 1.1 is the protocol implemented by GnuTLS.
758
TLS 1.2 is the protocol implemented by GnuTLS.
713
RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer
718
This is implemented by GnuTLS and used by this server so
719
that OpenPGP keys can be used.
774
RFC 7250: <citetitle>Using Raw Public Keys in Transport
775
Layer Security (TLS) and Datagram Transport Layer Security
780
This is implemented by GnuTLS version 3.6.6 and is, if
781
present, used by this server so that raw public keys can be
788
RFC 6091: <citetitle>Using OpenPGP Keys for Transport Layer
789
Security (TLS) Authentication</citetitle>
793
This is implemented by GnuTLS before version 3.6.0 and is,
794
if present, used by this server so that OpenPGP keys can be