1
1
<?xml version="1.0" encoding="UTF-8"?>
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
<!ENTITY VERSION "1.0">
4
5
<!ENTITY COMMANDNAME "mandos">
5
<!ENTITY TIMESTAMP "2022-04-24">
6
<!ENTITY % common SYSTEM "common.ent">
6
<!ENTITY TIMESTAMP "2008-09-02">
10
9
<refentry xmlns:xi="http://www.w3.org/2001/XInclude">
12
11
<title>Mandos Manual</title>
13
12
<!-- NWalsh’s docbook scripts use this to generate the footer: -->
14
13
<productname>Mandos</productname>
15
<productnumber>&version;</productnumber>
14
<productnumber>&VERSION;</productnumber>
16
15
<date>&TIMESTAMP;</date>
19
18
<firstname>Björn</firstname>
20
19
<surname>Påhlsson</surname>
22
<email>belorn@recompile.se</email>
21
<email>belorn@fukt.bsnet.se</email>
26
25
<firstname>Teddy</firstname>
27
26
<surname>Hogeborn</surname>
29
<email>teddy@recompile.se</email>
28
<email>teddy@fukt.bsnet.se</email>
46
34
<holder>Teddy Hogeborn</holder>
47
35
<holder>Björn Påhlsson</holder>
49
37
<xi:include href="legalnotice.xml"/>
53
41
<refentrytitle>&COMMANDNAME;</refentrytitle>
54
42
<manvolnum>8</manvolnum>
95
83
<replaceable>DIRECTORY</replaceable></option></arg>
97
85
<arg><option>--debug</option></arg>
99
<arg><option>--debuglevel
100
<replaceable>LEVEL</replaceable></option></arg>
102
<arg><option>--no-dbus</option></arg>
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>
119
88
<command>&COMMANDNAME;</command>
131
100
<arg choice="plain"><option>--check</option></arg>
133
102
</refsynopsisdiv>
135
104
<refsect1 id="description">
136
105
<title>DESCRIPTION</title>
138
107
<command>&COMMANDNAME;</command> is a server daemon which
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.
108
handles incoming request for passwords for a pre-defined list of
109
client host computers. The Mandos server uses Zeroconf to
110
announce itself on the local network, and uses TLS to
111
communicate securely with and to authenticate the clients. The
112
Mandos server uses IPv6 to allow Mandos clients to use IPv6
113
link-local addresses, since the clients will probably not have
114
any other addresses configured (see <xref linkend="overview"/>).
115
Any authenticated client is then given the stored pre-encrypted
116
password for that specific client.
219
186
<xi:include href="mandos-options.xml" xpointer="debug"/>
224
<term><option>--debuglevel
225
<replaceable>LEVEL</replaceable></option></term>
228
Set the debugging log level.
229
<replaceable>LEVEL</replaceable> is a string, one of
230
<quote><literal>CRITICAL</literal></quote>,
231
<quote><literal>ERROR</literal></quote>,
232
<quote><literal>WARNING</literal></quote>,
233
<quote><literal>INFO</literal></quote>, or
234
<quote><literal>DEBUG</literal></quote>, in order of
235
increasing verbosity. The default level is
236
<quote><literal>WARNING</literal></quote>.
242
191
<term><option>--priority <replaceable>
243
192
PRIORITY</replaceable></option></term>
283
<term><option>--no-dbus</option></term>
285
<xi:include href="mandos-options.xml" xpointer="dbus"/>
287
See also <xref linkend="dbus_interface"/>.
293
<term><option>--no-ipv6</option></term>
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"/>
343
233
<refsect1 id="overview">
344
234
<title>OVERVIEW</title>
345
235
<xi:include href="overview.xml"/>
362
252
start a TLS protocol handshake with a slight quirk: the Mandos
363
253
server program acts as a TLS <quote>client</quote> while the
364
254
connecting Mandos client acts as a TLS <quote>server</quote>.
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.
255
The Mandos client must supply an OpenPGP certificate, and the
256
fingerprint of this certificate is used by the Mandos server to
257
look up (in a list read from <filename>clients.conf</filename>
258
at start time) which binary blob to give the client. No other
259
authentication or authorization is done by the server.
372
262
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
408
298
</tbody></tgroup></table>
411
301
<refsect1 id="checking">
412
302
<title>CHECKING</title>
414
304
The server will, by default, continually check that the clients
415
305
are still up. If a client has not been confirmed as being up
416
306
for some time, the client is assumed to be compromised and is no
417
longer eligible to receive the encrypted password. (Manual
418
intervention is required to re-enable a client.) The timeout,
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>
307
longer eligible to receive the encrypted password. The timeout,
308
checker program, and interval between checks can be configured
309
both globally and per client; see <citerefentry>
310
<refentrytitle>mandos-clients.conf</refentrytitle>
422
311
<manvolnum>5</manvolnum></citerefentry>.
426
<refsect1 id="approval">
427
<title>APPROVAL</title>
429
The server can be configured to require manual approval for a
430
client before it is sent its secret. The delay to wait for such
431
approval and the default action (approve or deny) can be
432
configured both globally and per client; see <citerefentry>
433
<refentrytitle>mandos-clients.conf</refentrytitle>
434
<manvolnum>5</manvolnum></citerefentry>. By default all clients
435
will be approved immediately without delay.
438
This can be used to deny a client its secret if not manually
439
approved within a specified time. It can also be used to make
440
the server delay before giving a client its secret, allowing
441
optional manual denying of this specific client.
446
315
<refsect1 id="logging">
447
316
<title>LOGGING</title>
449
318
The server will send log message with various severity levels to
450
<filename class="devicefile">/dev/log</filename>. With the
319
<filename>/dev/log</filename>. With the
451
320
<option>--debug</option> option, it will log even more messages,
452
321
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.
468
<refsect1 id="dbus_interface">
469
<title>D-BUS INTERFACE</title>
471
The server will by default provide a D-Bus system bus interface.
472
This interface will only be accessible by the root user or a
473
Mandos-specific user, if such a user exists. For documentation
474
of the D-Bus API, see the file <filename>DBUS-API</filename>.
478
325
<refsect1 id="exit_status">
479
326
<title>EXIT STATUS</title>
535
<term><filename>/run/mandos.pid</filename></term>
538
The file containing the process id of the
539
<command>&COMMANDNAME;</command> process started last.
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>
382
<term><filename>/var/run/mandos/mandos.pid</filename></term>
385
The file containing the process id of
386
<command>&COMMANDNAME;</command>.
391
<term><filename>/dev/log</filename></term>
562
394
The Unix domain socket to where local syslog messages are
585
417
backtrace. This could be considered a feature.
420
Currently, if a client is declared <quote>invalid</quote> due to
421
having timed out, the server does not record this fact onto
422
permanent storage. This has some security implications, see
423
<xref linkend="CLIENTS"/>.
426
There is currently no way of querying the server of the current
427
status of clients, other than analyzing its <systemitem
428
class="service">syslog</systemitem> output.
588
431
There is no fine-grained control over logging and debug output.
590
<xi:include href="bugs.xml"/>
434
Debug mode is conflated with running in the foreground.
437
The console log messages does not show a timestamp.
593
441
<refsect1 id="example">
603
451
<informalexample>
605
453
Run the server in debug mode, read configuration files from
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:
454
the <filename>~/mandos</filename> directory, and use the
455
Zeroconf service name <quote>Test</quote> to not collide with
456
any other official Mandos server on this host:
628
476
</informalexample>
631
479
<refsect1 id="security">
632
480
<title>SECURITY</title>
633
<refsect2 id="server">
481
<refsect2 id="SERVER">
634
482
<title>SERVER</title>
636
484
Running this <command>&COMMANDNAME;</command> server program
637
485
should not in itself present any security risk to the host
638
computer running it. The program switches to a non-root user
486
computer running it. The program does not need any special
487
privileges to run, and is designed to run as a non-root user.
642
<refsect2 id="clients">
490
<refsect2 id="CLIENTS">
643
491
<title>CLIENTS</title>
645
493
The server only gives out its stored data to clients which
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>
494
does have the OpenPGP key of the stored fingerprint. This is
495
guaranteed by the fact that the client sends its OpenPGP
496
public key in the TLS handshake; this ensures it to be
497
genuine. The server computes the fingerprint of the key
498
itself and looks up the fingerprint in its list of
499
clients. The <filename>clients.conf</filename> file (see
652
500
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
653
501
<manvolnum>5</manvolnum></citerefentry>)
654
502
<emphasis>must</emphasis> be made non-readable by anyone
655
except the user starting the server (usually root).
503
except the user running the server.
658
506
As detailed in <xref linkend="checking"/>, the status of all
660
508
compromised if they are gone for too long.
511
If a client is compromised, its downtime should be duly noted
512
by the server which would therefore declare the client
513
invalid. But if the server was ever restarted, it would
514
re-read its client list from its configuration file and again
515
regard all clients therein as valid, and hence eligible to
516
receive their passwords. Therefore, be careful when
517
restarting servers if it is suspected that a client has, in
518
fact, been compromised by parties who may now be running a
519
fake Mandos client with the keys from the non-encrypted
520
initial <acronym>RAM</acronym> image of the client host. What
521
should be done in that case (if restarting the server program
522
really is necessary) is to stop the server program, edit the
523
configuration file to omit any suspect clients, and restart
663
527
For more details on client-side security, see
664
<citerefentry><refentrytitle>mandos-client</refentrytitle>
528
<citerefentry><refentrytitle>password-request</refentrytitle>
665
529
<manvolnum>8mandos</manvolnum></citerefentry>.
670
534
<refsect1 id="see_also">
671
535
<title>SEE ALSO</title>
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>
538
<refentrytitle>mandos-clients.conf</refentrytitle>
539
<manvolnum>5</manvolnum></citerefentry>, <citerefentry>
540
<refentrytitle>mandos.conf</refentrytitle>
541
<manvolnum>5</manvolnum></citerefentry>, <citerefentry>
542
<refentrytitle>password-request</refentrytitle>
543
<manvolnum>8mandos</manvolnum></citerefentry>, <citerefentry>
544
<refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum>
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
638
RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer
643
This is implemented by GnuTLS and used by this server so
644
that OpenPGP keys can be used.