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-client">
5
<!ENTITY TIMESTAMP "2023-10-21">
5
<!ENTITY TIMESTAMP "2018-02-08">
6
6
<!ENTITY % common SYSTEM "../common.ent">
96
95
<replaceable>FILE</replaceable></option></arg>
100
<arg choice="plain"><option>--tls-privkey
101
<replaceable>FILE</replaceable></option></arg>
102
<arg choice="plain"><option>-t
103
<replaceable>FILE</replaceable></option></arg>
107
<arg choice="plain"><option>--tls-pubkey
108
<replaceable>FILE</replaceable></option></arg>
109
<arg choice="plain"><option>-T
110
<replaceable>FILE</replaceable></option></arg>
114
99
<option>--priority <replaceable>STRING</replaceable></option>
169
154
brings up network interfaces, uses the interfaces’ IPv6
170
155
link-local addresses to get network connectivity, uses Zeroconf
171
156
to find servers on the local network, and communicates with
172
servers using TLS with a raw public key to ensure authenticity
173
and confidentiality. This client program keeps running, trying
174
all servers on the network, until it receives a satisfactory
175
reply or a TERM signal. After all servers have been tried, all
157
servers using TLS with an OpenPGP key to ensure authenticity and
158
confidentiality. This client program keeps running, trying all
159
servers on the network, until it receives a satisfactory reply
160
or a TERM signal. After all servers have been tried, all
176
161
servers are periodically retried. If no servers are found it
177
162
will wait indefinitely for new servers to appear.
198
183
This program is not meant to be run directly; it is really meant
199
to be run by other programs in the initial
200
<acronym>RAM</acronym> disk environment; see <xref
201
linkend="overview"/>.
184
to run as a plugin of the <application>Mandos</application>
185
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
186
<manvolnum>8mandos</manvolnum></citerefentry>, which runs in the
187
initial <acronym>RAM</acronym> disk environment because it is
188
specified as a <quote>keyscript</quote> in the <citerefentry>
189
<refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum>
190
</citerefentry> file.
216
205
<title>OPTIONS</title>
218
207
This program is commonly not invoked from the command line; it
219
is normally started by another program as described in <xref
220
linkend="description"/>. Any command line options this program
221
accepts are therefore normally provided by the invoking program,
208
is normally started by the <application>Mandos</application>
209
plugin runner, see <citerefentry><refentrytitle
210
>plugin-runner</refentrytitle><manvolnum>8mandos</manvolnum>
211
</citerefentry>. Any command line options this program accepts
212
are therefore normally provided by the plugin runner, and not
319
<term><option>--tls-pubkey=<replaceable
320
>FILE</replaceable></option></term>
322
<replaceable>FILE</replaceable></option></term>
325
TLS raw public key file name. The default name is
326
<quote><filename>/conf/conf.d/mandos/tls-pubkey.pem</filename
333
<term><option>--tls-privkey=<replaceable
334
>FILE</replaceable></option></term>
336
<replaceable>FILE</replaceable></option></term>
339
TLS secret key file name. The default name is
340
<quote><filename>/conf/conf.d/mandos/tls-privkey.pem</filename
347
310
<term><option>--priority=<replaceable
348
311
>STRING</replaceable></option></term>
360
323
Sets the number of bits to use for the prime number in the
361
324
TLS Diffie-Hellman key exchange. The default value is
362
selected automatically based on the GnuTLS security
363
profile set in its priority string. Note that if the
364
<option>--dh-params</option> option is used, the values
365
from that file will be used instead.
325
selected automatically based on the OpenPGP key. Note
326
that if the <option>--dh-params</option> option is used,
327
the values from that file will be used instead.
476
438
<title>OVERVIEW</title>
477
439
<xi:include href="../overview.xml"/>
479
This program is the client part. It is run automatically in an
480
initial <acronym>RAM</acronym> disk environment.
483
In an initial <acronym>RAM</acronym> disk environment using
484
<citerefentry><refentrytitle>systemd</refentrytitle>
485
<manvolnum>1</manvolnum></citerefentry>, this program is started
486
by the <application>Mandos</application> <citerefentry>
487
<refentrytitle>password-agent</refentrytitle>
488
<manvolnum>8mandos</manvolnum></citerefentry>, which in turn is
489
started automatically by the <citerefentry>
490
<refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum>
491
</citerefentry> <quote>Password Agent</quote> system.
494
In the case of a non-<citerefentry>
495
<refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum>
496
</citerefentry> environment, this program is started as a plugin
497
of the <application>Mandos</application> <citerefentry>
498
<refentrytitle>plugin-runner</refentrytitle>
499
<manvolnum>8mandos</manvolnum></citerefentry>, which runs in the
500
initial <acronym>RAM</acronym> disk environment because it is
501
specified as a <quote>keyscript</quote> in the <citerefentry>
502
<refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum>
503
</citerefentry> file.
441
This program is the client part. It is a plugin started by
442
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
443
<manvolnum>8mandos</manvolnum></citerefentry> which will run in
444
an initial <acronym>RAM</acronym> disk environment.
506
447
This program could, theoretically, be used as a keyscript in
507
448
<filename>/etc/crypttab</filename>, but it would then be
508
449
impossible to enter a password for the encrypted root disk at
509
450
the console, since this program does not read from the console
451
at all. This is why a separate plugin runner (<citerefentry>
452
<refentrytitle>plugin-runner</refentrytitle>
453
<manvolnum>8mandos</manvolnum></citerefentry>) is used to run
454
both this program and others in in parallel,
455
<emphasis>one</emphasis> of which (<citerefentry>
456
<refentrytitle>password-prompt</refentrytitle>
457
<manvolnum>8mandos</manvolnum></citerefentry>) will prompt for
458
passwords on the system console.
534
482
This environment variable will be assumed to contain the
535
483
directory containing any helper executables. The use and
536
nature of these helper executables, if any, is purposely
484
nature of these helper executables, if any, is
485
purposefully not documented.
737
<term><filename>/conf/conf.d/mandos/tls-pubkey.pem</filename
739
<term><filename>/conf/conf.d/mandos/tls-privkey.pem</filename
743
Public and private raw key files, in <quote>PEM</quote>
744
format. These are the default file names, they can be
745
changed with the <option>--tls-pubkey</option> and
746
<option>--tls-privkey</option> options.
752
686
class="directory">/lib/mandos/network-hooks.d</filename></term>
770
704
<title>EXAMPLE</title>
772
706
Note that normally, command line options will not be given
773
directly, but passed on via the program responsible for starting
774
this program; see <xref linkend="overview"/>.
707
directly, but via options for the Mandos <citerefentry
708
><refentrytitle>plugin-runner</refentrytitle>
709
<manvolnum>8mandos</manvolnum></citerefentry>.
776
711
<informalexample>
794
729
</informalexample>
795
730
<informalexample>
797
Run in debug mode, and use custom keys:
732
Run in debug mode, and use a custom key:
801
736
<!-- do not wrap this line -->
802
<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt --tls-pubkey keydir/tls-pubkey.pem --tls-privkey keydir/tls-privkey.pem</userinput>
737
<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt</userinput>
805
740
</informalexample>
806
741
<informalexample>
808
Run in debug mode, with custom keys, and do not use Zeroconf
743
Run in debug mode, with a custom key, and do not use Zeroconf
809
744
to locate a server; connect directly to the IPv6 link-local
810
745
address <quote><systemitem class="ipaddress"
811
746
>fe80::aede:48ff:fe71:f6f2</systemitem></quote>, port 4711,
823
758
<refsect1 id="security">
824
759
<title>SECURITY</title>
826
This program assumes that it is set-uid to root, and will switch
827
back to the original (and presumably non-privileged) user and
828
group after bringing up the network interface.
761
This program is set-uid to root, but will switch back to the
762
original (and presumably non-privileged) user and group after
763
bringing up the network interface.
831
766
To use this program for its intended purpose (see <xref
845
780
The only remaining weak point is that someone with physical
846
781
access to the client hard drive might turn off the client
847
computer, read the OpenPGP and TLS keys directly from the hard
848
drive, and communicate with the server. To safeguard against
849
this, the server is supposed to notice the client disappearing
850
and stop giving out the encrypted data. Therefore, it is
851
important to set the timeout and checker interval values tightly
852
on the server. See <citerefentry><refentrytitle
782
computer, read the OpenPGP keys directly from the hard drive,
783
and communicate with the server. To safeguard against this, the
784
server is supposed to notice the client disappearing and stop
785
giving out the encrypted data. Therefore, it is important to
786
set the timeout and checker interval values tightly on the
787
server. See <citerefentry><refentrytitle
853
788
>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
879
814
<manvolnum>5</manvolnum></citerefentry>,
880
815
<citerefentry><refentrytitle>mandos</refentrytitle>
881
816
<manvolnum>8</manvolnum></citerefentry>,
882
<citerefentry><refentrytitle>password-agent</refentrytitle>
817
<citerefentry><refentrytitle>password-prompt</refentrytitle>
883
818
<manvolnum>8mandos</manvolnum></citerefentry>,
884
819
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
885
820
<manvolnum>8mandos</manvolnum></citerefentry>
990
RFC 7250: <citetitle>Using Raw Public Keys in Transport
991
Layer Security (TLS) and Datagram Transport Layer Security
996
This is implemented by GnuTLS in version 3.6.6 and is, if
997
present, used by this program so that raw public keys can be
1004
925
RFC 6091: <citetitle>Using OpenPGP Keys for Transport Layer
1005
926
Security</citetitle>
1009
This is implemented by GnuTLS before version 3.6.0 and is,
1010
if present, used by this program so that OpenPGP keys can be
930
This is implemented by GnuTLS and used by this program so
931
that OpenPGP keys can be used.