171
137
communicates with <citerefentry><refentrytitle
172
138
>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>
173
139
to get a password. In slightly more detail, this client program
174
brings up network interfaces, uses the interfaces’ IPv6
175
link-local addresses to get network connectivity, uses Zeroconf
176
to find servers on the local network, and communicates with
177
servers using TLS with a raw public key to ensure authenticity
178
and confidentiality. This client program keeps running, trying
179
all servers on the network, until it receives a satisfactory
180
reply or a TERM signal. After all servers have been tried, all
140
brings up a network interface, uses the interface’s IPv6
141
link-local address to get network connectivity, uses Zeroconf to
142
find servers on the local network, and communicates with servers
143
using TLS with an OpenPGP key to ensure authenticity and
144
confidentiality. This client program keeps running, trying all
145
servers on the network, until it receives a satisfactory reply
146
or a TERM signal. After all servers have been tried, all
181
147
servers are periodically retried. If no servers are found it
182
148
will wait indefinitely for new servers to appear.
185
The network interfaces are selected like this: If any interfaces
186
are specified using the <option>--interface</option> option,
187
those interface are used. Otherwise,
188
<command>&COMMANDNAME;</command> will use all interfaces that
189
are not loopback interfaces, are not point-to-point interfaces,
190
are capable of broadcasting and do not have the NOARP flag (see
151
The network interface is selected like this: If an interface is
152
specified using the <option>--interface</option> option, that
153
interface is used. Otherwise, <command>&COMMANDNAME;</command>
154
will choose any interface that is up and running and is not a
155
loopback interface, is not a point-to-point interface, is
156
capable of broadcasting and does not have the NOARP flag (see
191
157
<citerefentry><refentrytitle>netdevice</refentrytitle>
192
158
<manvolnum>7</manvolnum></citerefentry>). (If the
193
159
<option>--connect</option> option is used, point-to-point
194
interfaces and non-broadcast interfaces are accepted.) If any
195
used interfaces are not up and running, they are first taken up
196
(and later taken down again on program exit).
160
interfaces and non-broadcast interfaces are accepted.) If no
161
acceptable interfaces are found, re-run the check but without
162
the <quote>up and running</quote> requirement, and manually take
163
the selected interface up (and later take it down on program
199
Before network interfaces are selected, all <quote>network
167
Before a network interface is selected, all <quote>network
200
168
hooks</quote> are run; see <xref linkend="network-hooks"/>.
203
171
This program is not meant to be run directly; it is really meant
204
to be run by other programs in the initial
205
<acronym>RAM</acronym> disk environment; see <xref
206
linkend="overview"/>.
172
to run as a plugin of the <application>Mandos</application>
173
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
174
<manvolnum>8mandos</manvolnum></citerefentry>, which runs in the
175
initial <acronym>RAM</acronym> disk environment because it is
176
specified as a <quote>keyscript</quote> in the <citerefentry>
177
<refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum>
178
</citerefentry> file.
221
193
<title>OPTIONS</title>
223
195
This program is commonly not invoked from the command line; it
224
is normally started by another program as described in <xref
225
linkend="description"/>. Any command line options this program
226
accepts are therefore normally provided by the invoking program,
196
is normally started by the <application>Mandos</application>
197
plugin runner, see <citerefentry><refentrytitle
198
>plugin-runner</refentrytitle><manvolnum>8mandos</manvolnum>
199
</citerefentry>. Any command line options this program accepts
200
are therefore normally provided by the plugin runner, and not
244
218
assumed to separate the address from the port number.
247
Normally, Zeroconf would be used to locate Mandos servers,
248
in which case this option would only be used when testing
221
This option is normally only useful for testing and
255
228
<term><option>--interface=<replaceable
256
>NAME</replaceable><arg rep='repeat'>,<replaceable
257
>NAME</replaceable></arg></option></term>
229
>NAME</replaceable></option></term>
259
<replaceable>NAME</replaceable><arg rep='repeat'>,<replaceable
260
>NAME</replaceable></arg></option></term>
231
<replaceable>NAME</replaceable></option></term>
263
Comma separated list of network interfaces that will be
264
brought up and scanned for Mandos servers to connect to.
265
The default is the empty string, which will automatically
266
use all appropriate interfaces.
234
Network interface that will be brought up and scanned for
235
Mandos servers to connect to. The default is the empty
236
string, which will automatically choose an appropriate
269
If the <option>--connect</option> option is used, and
270
exactly one interface name is specified (except
271
<quote><literal>none</literal></quote>), this specifies
272
the interface to use to connect to the address given.
240
If the <option>--connect</option> option is used, this
241
specifies the interface to use to connect to the address
275
245
Note that since this program will normally run in the
276
246
initial RAM disk environment, the interface must be an
277
247
interface which exists at that stage. Thus, the interface
278
can normally not be a pseudo-interface such as
279
<quote>br0</quote> or <quote>tun0</quote>; such interfaces
280
will not exist until much later in the boot process, and
281
can not be used by this program, unless created by a
282
<quote>network hook</quote> — see <xref
283
linkend="network-hooks"/>.
248
can not be a pseudo-interface such as <quote>br0</quote>
249
or <quote>tun0</quote>; such interfaces will not exist
250
until much later in the boot process, and can not be used
251
by this program, unless created by a <quote>network
252
hook</quote> — see <xref linkend="network-hooks"/>.
286
255
<replaceable>NAME</replaceable> can be the string
287
<quote><literal>none</literal></quote>; this will make
288
<command>&COMMANDNAME;</command> only bring up interfaces
289
specified <emphasis>before</emphasis> this string. This
290
is not recommended, and only meant for advanced users.
256
<quote><literal>none</literal></quote>; this will not use
257
any specific interface, and will not bring up an interface
258
on startup. This is not recommended, and only meant for
324
<term><option>--tls-pubkey=<replaceable
325
>FILE</replaceable></option></term>
327
<replaceable>FILE</replaceable></option></term>
330
TLS raw public key file name. The default name is
331
<quote><filename>/conf/conf.d/mandos/tls-pubkey.pem</filename
338
<term><option>--tls-privkey=<replaceable
339
>FILE</replaceable></option></term>
341
<replaceable>FILE</replaceable></option></term>
344
TLS secret key file name. The default name is
345
<quote><filename>/conf/conf.d/mandos/tls-privkey.pem</filename
352
293
<term><option>--priority=<replaceable
353
294
>STRING</replaceable></option></term>
365
306
Sets the number of bits to use for the prime number in the
366
TLS Diffie-Hellman key exchange. The default value is
367
selected automatically based on the GnuTLS security
368
profile set in its priority string. Note that if the
369
<option>--dh-params</option> option is used, the values
370
from that file will be used instead.
376
<term><option>--dh-params=<replaceable
377
>FILE</replaceable></option></term>
380
Specifies a PEM-encoded PKCS#3 file to read the parameters
381
needed by the TLS Diffie-Hellman key exchange from. If
382
this option is not given, or if the file for some reason
383
could not be used, the parameters will be generated on
384
startup, which will take some time and processing power.
385
Those using servers running under time, power or processor
386
constraints may want to generate such a file in advance
307
TLS Diffie-Hellman key exchange. Default is 1024.
481
401
<title>OVERVIEW</title>
482
402
<xi:include href="../overview.xml"/>
484
This program is the client part. It is run automatically in an
485
initial <acronym>RAM</acronym> disk environment.
488
In an initial <acronym>RAM</acronym> disk environment using
489
<citerefentry><refentrytitle>systemd</refentrytitle>
490
<manvolnum>1</manvolnum></citerefentry>, this program is started
491
by the <application>Mandos</application> <citerefentry>
492
<refentrytitle>password-agent</refentrytitle>
493
<manvolnum>8mandos</manvolnum></citerefentry>, which in turn is
494
started automatically by the <citerefentry>
495
<refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum>
496
</citerefentry> <quote>Password Agent</quote> system.
499
In the case of a non-<citerefentry>
500
<refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum>
501
</citerefentry> environment, this program is started as a plugin
502
of the <application>Mandos</application> <citerefentry>
503
<refentrytitle>plugin-runner</refentrytitle>
504
<manvolnum>8mandos</manvolnum></citerefentry>, which runs in the
505
initial <acronym>RAM</acronym> disk environment because it is
506
specified as a <quote>keyscript</quote> in the <citerefentry>
507
<refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum>
508
</citerefentry> file.
404
This program is the client part. It is a plugin started by
405
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
406
<manvolnum>8mandos</manvolnum></citerefentry> which will run in
407
an initial <acronym>RAM</acronym> disk environment.
511
410
This program could, theoretically, be used as a keyscript in
512
411
<filename>/etc/crypttab</filename>, but it would then be
513
412
impossible to enter a password for the encrypted root disk at
514
413
the console, since this program does not read from the console
414
at all. This is why a separate plugin runner (<citerefentry>
415
<refentrytitle>plugin-runner</refentrytitle>
416
<manvolnum>8mandos</manvolnum></citerefentry>) is used to run
417
both this program and others in in parallel,
418
<emphasis>one</emphasis> of which (<citerefentry>
419
<refentrytitle>password-prompt</refentrytitle>
420
<manvolnum>8mandos</manvolnum></citerefentry>) will prompt for
421
passwords on the system console.
532
438
<refsect1 id="environment">
533
439
<title>ENVIRONMENT</title>
536
<term><envar>MANDOSPLUGINHELPERDIR</envar></term>
539
This environment variable will be assumed to contain the
540
directory containing any helper executables. The use and
541
nature of these helper executables, if any, is purposely
548
This program does not use any other environment variables, not
549
even the ones provided by <citerefentry><refentrytitle
441
This program does not use any environment variables, not even
442
the ones provided by <citerefentry><refentrytitle
550
443
>cryptsetup</refentrytitle><manvolnum>8</manvolnum>
654
547
<term><envar>DEVICE</envar></term>
657
The network interfaces, as specified to
550
The network interface, as specified to
658
551
<command>&COMMANDNAME;</command> by the
659
<option>--interface</option> option, combined to one
660
string and separated by commas. If this is set, and
661
does not contain the interface a hook will bring up,
662
there is no reason for a hook to continue.
552
<option>--interface</option> option. If this is not the
553
interface a hook will bring up, there is no reason for a
771
<xi:include href="../bugs.xml"/>
647
<!-- <refsect1 id="bugs"> -->
648
<!-- <title>BUGS</title> -->
774
653
<refsect1 id="example">
775
654
<title>EXAMPLE</title>
777
656
Note that normally, command line options will not be given
778
directly, but passed on via the program responsible for starting
779
this program; see <xref linkend="overview"/>.
657
directly, but via options for the Mandos <citerefentry
658
><refentrytitle>plugin-runner</refentrytitle>
659
<manvolnum>8mandos</manvolnum></citerefentry>.
781
661
<informalexample>
783
Normal invocation needs no options, if the network interfaces
784
can be automatically determined:
663
Normal invocation needs no options, if the network interface
664
is <quote>eth0</quote>:
787
667
<userinput>&COMMANDNAME;</userinput>
799
679
</informalexample>
800
680
<informalexample>
802
Run in debug mode, and use custom keys:
682
Run in debug mode, and use a custom key:
806
686
<!-- do not wrap this line -->
807
<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt --tls-pubkey keydir/tls-pubkey.pem --tls-privkey keydir/tls-privkey.pem</userinput>
687
<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt</userinput>
810
690
</informalexample>
811
691
<informalexample>
813
Run in debug mode, with custom keys, and do not use Zeroconf
693
Run in debug mode, with a custom key, and do not use Zeroconf
814
694
to locate a server; connect directly to the IPv6 link-local
815
695
address <quote><systemitem class="ipaddress"
816
696
>fe80::aede:48ff:fe71:f6f2</systemitem></quote>, port 4711,
850
730
The only remaining weak point is that someone with physical
851
731
access to the client hard drive might turn off the client
852
computer, read the OpenPGP and TLS keys directly from the hard
853
drive, and communicate with the server. To safeguard against
854
this, the server is supposed to notice the client disappearing
855
and stop giving out the encrypted data. Therefore, it is
856
important to set the timeout and checker interval values tightly
857
on the server. See <citerefentry><refentrytitle
732
computer, read the OpenPGP keys directly from the hard drive,
733
and communicate with the server. To safeguard against this, the
734
server is supposed to notice the client disappearing and stop
735
giving out the encrypted data. Therefore, it is important to
736
set the timeout and checker interval values tightly on the
737
server. See <citerefentry><refentrytitle
858
738
>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
861
741
It will also help if the checker program on the server is
862
742
configured to request something from the client which can not be
863
spoofed by someone else on the network, like SSH server key
864
fingerprints, and unlike unencrypted <acronym>ICMP</acronym>
865
echo (<quote>ping</quote>) replies.
743
spoofed by someone else on the network, unlike unencrypted
744
<acronym>ICMP</acronym> echo (<quote>ping</quote>) replies.
868
747
<emphasis>Note</emphasis>: This makes it completely insecure to
995
RFC 7250: <citetitle>Using Raw Public Keys in Transport
996
Layer Security (TLS) and Datagram Transport Layer Security
1001
This is implemented by GnuTLS in version 3.6.6 and is, if
1002
present, used by this program so that raw public keys can be
1009
RFC 6091: <citetitle>Using OpenPGP Keys for Transport Layer
875
RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer
1010
876
Security</citetitle>
1014
This is implemented by GnuTLS before version 3.6.0 and is,
1015
if present, used by this program so that OpenPGP keys can be
880
This is implemented by GnuTLS and used by this program so
881
that OpenPGP keys can be used.