137
166
communicates with <citerefentry><refentrytitle
138
167
>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>
139
168
to get a password. In slightly more detail, this client program
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
169
brings up network interfaces, uses the interfaces’ IPv6
170
link-local addresses to get network connectivity, uses Zeroconf
171
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
147
176
servers are periodically retried. If no servers are found it
148
177
will wait indefinitely for new servers to appear.
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
180
The network interfaces are selected like this: If any interfaces
181
are specified using the <option>--interface</option> option,
182
those interface are used. Otherwise,
183
<command>&COMMANDNAME;</command> will use all interfaces that
184
are not loopback interfaces, are not point-to-point interfaces,
185
are capable of broadcasting and do not have the NOARP flag (see
157
186
<citerefentry><refentrytitle>netdevice</refentrytitle>
158
187
<manvolnum>7</manvolnum></citerefentry>). (If the
159
188
<option>--connect</option> option is used, point-to-point
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
189
interfaces and non-broadcast interfaces are accepted.) If any
190
used interfaces are not up and running, they are first taken up
191
(and later taken down again on program exit).
167
Before a network interface is selected, all <quote>network
194
Before network interfaces are selected, all <quote>network
168
195
hooks</quote> are run; see <xref linkend="network-hooks"/>.
171
198
This program is not meant to be run directly; it is really meant
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.
199
to be run by other programs in the initial
200
<acronym>RAM</acronym> disk environment; see <xref
201
linkend="overview"/>.
193
216
<title>OPTIONS</title>
195
218
This program is commonly not invoked from the command line; it
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
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,
218
239
assumed to separate the address from the port number.
221
This option is normally only useful for testing and
242
Normally, Zeroconf would be used to locate Mandos servers,
243
in which case this option would only be used when testing
228
250
<term><option>--interface=<replaceable
229
>NAME</replaceable></option></term>
251
>NAME</replaceable><arg rep='repeat'>,<replaceable
252
>NAME</replaceable></arg></option></term>
231
<replaceable>NAME</replaceable></option></term>
254
<replaceable>NAME</replaceable><arg rep='repeat'>,<replaceable
255
>NAME</replaceable></arg></option></term>
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
258
Comma separated list of network interfaces that will be
259
brought up and scanned for Mandos servers to connect to.
260
The default is the empty string, which will automatically
261
use all appropriate interfaces.
240
If the <option>--connect</option> option is used, this
241
specifies the interface to use to connect to the address
264
If the <option>--connect</option> option is used, and
265
exactly one interface name is specified (except
266
<quote><literal>none</literal></quote>), this specifies
267
the interface to use to connect to the address given.
245
270
Note that since this program will normally run in the
246
271
initial RAM disk environment, the interface must be an
247
272
interface which exists at that stage. Thus, the interface
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"/>.
273
can normally not be a pseudo-interface such as
274
<quote>br0</quote> or <quote>tun0</quote>; such interfaces
275
will not exist until much later in the boot process, and
276
can not be used by this program, unless created by a
277
<quote>network hook</quote> — see <xref
278
linkend="network-hooks"/>.
255
281
<replaceable>NAME</replaceable> can be the string
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
282
<quote><literal>none</literal></quote>; this will make
283
<command>&COMMANDNAME;</command> only bring up interfaces
284
specified <emphasis>before</emphasis> this string. This
285
is not recommended, and only meant for advanced users.
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
293
347
<term><option>--priority=<replaceable
294
348
>STRING</replaceable></option></term>
306
360
Sets the number of bits to use for the prime number in the
307
TLS Diffie-Hellman key exchange. Default is 1024.
361
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.
371
<term><option>--dh-params=<replaceable
372
>FILE</replaceable></option></term>
375
Specifies a PEM-encoded PKCS#3 file to read the parameters
376
needed by the TLS Diffie-Hellman key exchange from. If
377
this option is not given, or if the file for some reason
378
could not be used, the parameters will be generated on
379
startup, which will take some time and processing power.
380
Those using servers running under time, power or processor
381
constraints may want to generate such a file in advance
401
476
<title>OVERVIEW</title>
402
477
<xi:include href="../overview.xml"/>
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.
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.
410
506
This program could, theoretically, be used as a keyscript in
411
507
<filename>/etc/crypttab</filename>, but it would then be
412
508
impossible to enter a password for the encrypted root disk at
413
509
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.
438
527
<refsect1 id="environment">
439
528
<title>ENVIRONMENT</title>
531
<term><envar>MANDOSPLUGINHELPERDIR</envar></term>
534
This environment variable will be assumed to contain the
535
directory containing any helper executables. The use and
536
nature of these helper executables, if any, is purposely
441
This program does not use any environment variables, not even
442
the ones provided by <citerefentry><refentrytitle
543
This program does not use any other environment variables, not
544
even the ones provided by <citerefentry><refentrytitle
443
545
>cryptsetup</refentrytitle><manvolnum>8</manvolnum>
497
599
<term><literal>files</literal></term>
500
This should make the network hook print, <emphasis>on
501
separate lines</emphasis>, all the files needed for it
502
to run. (These files will be copied into the initial
503
RAM filesystem.) Intended use is for a network hook
504
which is a shell script to print its needed binaries.
602
This should make the network hook print, <emphasis>one
603
file per line</emphasis>, all the files needed for it to
604
run. (These files will be copied into the initial RAM
605
filesystem.) Typical use is for a network hook which is
606
a shell script to print its needed binaries.
507
609
It is not necessary to print any non-executable files
508
610
already in the network hook directory, these will be
509
611
copied implicitly if they otherwise satisfy the name
617
<term><literal>modules</literal></term>
620
This should make the network hook print, <emphasis>on
621
separate lines</emphasis>, all the kernel modules needed
622
for it to run. (These modules will be copied into the
623
initial RAM filesystem.) For instance, a tunnel
625
<quote><literal>tun</literal></quote> module.
534
649
<term><envar>DEVICE</envar></term>
537
The network interface, as specified to
652
The network interfaces, as specified to
538
653
<command>&COMMANDNAME;</command> by the
539
<option>--interface</option> option. If this is not the
540
interface a hook will bring up, there is no reason for a
654
<option>--interface</option> option, combined to one
655
string and separated by commas. If this is set, and
656
does not contain the interface a hook will bring up,
657
there is no reason for a hook to continue.
571
688
This will be the same as the <option>--delay</option>
572
option passed to <command>&COMMANDNAME;</command>.
689
option passed to <command>&COMMANDNAME;</command>. Is
690
only set if <envar>MODE</envar> is
691
<quote><literal>start</literal></quote> or
692
<quote><literal>stop</literal></quote>.
697
<term><envar>CONNECT</envar></term>
700
This will be the same as the <option>--connect</option>
701
option passed to <command>&COMMANDNAME;</command>. Is
702
only set if <option>--connect</option> is passed and
703
<envar>MODE</envar> is
704
<quote><literal>start</literal></quote> or
705
<quote><literal>stop</literal></quote>.
617
<!-- <refsect1 id="bugs"> -->
618
<!-- <title>BUGS</title> -->
766
<xi:include href="../bugs.xml"/>
623
769
<refsect1 id="example">
624
770
<title>EXAMPLE</title>
626
772
Note that normally, command line options will not be given
627
directly, but via options for the Mandos <citerefentry
628
><refentrytitle>plugin-runner</refentrytitle>
629
<manvolnum>8mandos</manvolnum></citerefentry>.
773
directly, but passed on via the program responsible for starting
774
this program; see <xref linkend="overview"/>.
631
776
<informalexample>
633
Normal invocation needs no options, if the network interface
634
is <quote>eth0</quote>:
778
Normal invocation needs no options, if the network interfaces
779
can be automatically determined:
637
782
<userinput>&COMMANDNAME;</userinput>
649
794
</informalexample>
650
795
<informalexample>
652
Run in debug mode, and use a custom key:
797
Run in debug mode, and use custom keys:
656
801
<!-- do not wrap this line -->
657
<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt</userinput>
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>
660
805
</informalexample>
661
806
<informalexample>
663
Run in debug mode, with a custom key, and do not use Zeroconf
808
Run in debug mode, with custom keys, and do not use Zeroconf
664
809
to locate a server; connect directly to the IPv6 link-local
665
810
address <quote><systemitem class="ipaddress"
666
811
>fe80::aede:48ff:fe71:f6f2</systemitem></quote>, port 4711,
700
845
The only remaining weak point is that someone with physical
701
846
access to the client hard drive might turn off the client
702
computer, read the OpenPGP keys directly from the hard drive,
703
and communicate with the server. To safeguard against this, the
704
server is supposed to notice the client disappearing and stop
705
giving out the encrypted data. Therefore, it is important to
706
set the timeout and checker interval values tightly on the
707
server. See <citerefentry><refentrytitle
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
708
853
>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
711
856
It will also help if the checker program on the server is
712
857
configured to request something from the client which can not be
713
spoofed by someone else on the network, unlike unencrypted
714
<acronym>ICMP</acronym> echo (<quote>ping</quote>) replies.
858
spoofed by someone else on the network, like SSH server key
859
fingerprints, and unlike unencrypted <acronym>ICMP</acronym>
860
echo (<quote>ping</quote>) replies.
717
863
<emphasis>Note</emphasis>: This makes it completely insecure to
845
RFC 5081: <citetitle>Using OpenPGP Keys for Transport Layer
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
RFC 6091: <citetitle>Using OpenPGP Keys for Transport Layer
846
1005
Security</citetitle>
850
This is implemented by GnuTLS and used by this program so
851
that OpenPGP keys can be used.
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