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 "2011-08-08">
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>
94
102
<arg><option>--no-dbus</option></arg>
96
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>
99
119
<command>&COMMANDNAME;</command>
116
136
<title>DESCRIPTION</title>
118
138
<command>&COMMANDNAME;</command> is a server daemon which
119
handles incoming request for passwords for a pre-defined list of
120
client host computers. The Mandos server uses Zeroconf to
121
announce itself on the local network, and uses TLS to
122
communicate securely with and to authenticate the clients. The
123
Mandos server uses IPv6 to allow Mandos clients to use IPv6
124
link-local addresses, since the clients will probably not have
125
any other addresses configured (see <xref linkend="overview"/>).
126
Any authenticated client is then given the stored pre-encrypted
127
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.
273
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"/>
298
362
start a TLS protocol handshake with a slight quirk: the Mandos
299
363
server program acts as a TLS <quote>client</quote> while the
300
364
connecting Mandos client acts as a TLS <quote>server</quote>.
301
The Mandos client must supply an OpenPGP certificate, and the
302
fingerprint of this certificate is used by the Mandos server to
303
look up (in a list read from <filename>clients.conf</filename>
304
at start time) which binary blob to give the client. No other
305
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.
308
372
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
352
416
for some time, the client is assumed to be compromised and is no
353
417
longer eligible to receive the encrypted password. (Manual
354
418
intervention is required to re-enable a client.) The timeout,
355
checker program, and interval between checks can be configured
356
both globally and per client; see <citerefentry>
357
<refentrytitle>mandos-clients.conf</refentrytitle>
358
<manvolnum>5</manvolnum></citerefentry>. A client successfully
359
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>.
385
447
<title>LOGGING</title>
387
449
The server will send log message with various severity levels to
388
<filename>/dev/log</filename>. With the
450
<filename class="devicefile">/dev/log</filename>. With the
389
451
<option>--debug</option> option, it will log even more messages,
390
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.
394
468
<refsect1 id="dbus_interface">
395
469
<title>D-BUS INTERFACE</title>
461
<term><filename>/var/run/mandos.pid</filename></term>
535
<term><filename>/run/mandos.pid</filename></term>
464
538
The file containing the process id of the
465
539
<command>&COMMANDNAME;</command> process started last.
470
<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>
473
562
The Unix domain socket to where local syslog messages are
496
585
backtrace. This could be considered a feature.
499
Currently, if a client is disabled due to having timed out, the
500
server does not record this fact onto permanent storage. This
501
has some security implications, see <xref linkend="clients"/>.
504
588
There is no fine-grained control over logging and debug output.
507
Debug mode is conflated with running in the foreground.
510
The console log messages do not show a time stamp.
513
This server does not check the expire time of clients’ OpenPGP
590
<xi:include href="bugs.xml"/>
518
593
<refsect1 id="example">
528
603
<informalexample>
530
605
Run the server in debug mode, read configuration files from
531
the <filename>~/mandos</filename> directory, and use the
532
Zeroconf service name <quote>Test</quote> to not collide with
533
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:
568
643
<title>CLIENTS</title>
570
645
The server only gives out its stored data to clients which
571
does have the OpenPGP key of the stored fingerprint. This is
572
guaranteed by the fact that the client sends its OpenPGP
573
public key in the TLS handshake; this ensures it to be
574
genuine. The server computes the fingerprint of the key
575
itself and looks up the fingerprint in its list of
576
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>
577
652
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
578
653
<manvolnum>5</manvolnum></citerefentry>)
579
654
<emphasis>must</emphasis> be made non-readable by anyone
585
660
compromised if they are gone for too long.
588
If a client is compromised, its downtime should be duly noted
589
by the server which would therefore disable the client. But
590
if the server was ever restarted, it would re-read its client
591
list from its configuration file and again regard all clients
592
therein as enabled, and hence eligible to receive their
593
passwords. Therefore, be careful when restarting servers if
594
it is suspected that a client has, in fact, been compromised
595
by parties who may now be running a fake Mandos client with
596
the keys from the non-encrypted initial <acronym>RAM</acronym>
597
image of the client host. What should be done in that case
598
(if restarting the server program really is necessary) is to
599
stop the server program, edit the configuration file to omit
600
any suspect clients, and restart the server program.
603
663
For more details on client-side security, see
604
664
<citerefentry><refentrytitle>mandos-client</refentrytitle>
605
665
<manvolnum>8mandos</manvolnum></citerefentry>.
649
<ulink url="http://www.gnu.org/software/gnutls/"
709
<ulink url="https://gnutls.org/">GnuTLS</ulink>
654
713
GnuTLS is the library this server uses to implement TLS for
655
714
communicating securely with the client, and at the same time
656
confidently get the client’s public OpenPGP key.
715
confidently get the client’s public key.
682
741
The clients use IPv6 link-local addresses, which are
683
immediately usable since a link-local addresses is
742
immediately usable since a link-local address is
684
743
automatically assigned to a network interfaces when it
694
RFC 4346: <citetitle>The Transport Layer Security (TLS)
695
Protocol Version 1.1</citetitle>
753
RFC 5246: <citetitle>The Transport Layer Security (TLS)
754
Protocol Version 1.2</citetitle>
699
TLS 1.1 is the protocol implemented by GnuTLS.
758
TLS 1.2 is the protocol implemented by GnuTLS.
715
RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer
720
This is implemented by GnuTLS and used by this server so
721
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
added
removed
mandos.xml
