121
<option>--dh-params <replaceable>FILE</replaceable></option>
125
<option>--delay <replaceable>SECONDS</replaceable></option>
129
<option>--retry <replaceable>SECONDS</replaceable></option>
133
<option>--network-hook-dir
134
<replaceable>DIR</replaceable></option>
138
124
<option>--debug</option>
142
128
<command>&COMMANDNAME;</command>
143
129
<group choice="req">
144
<arg choice="plain"><option>--help</option></arg>
145
<arg choice="plain"><option>-?</option></arg>
130
<arg choice='plain'><option>-?</option></arg>
131
<arg choice='plain'><option>--help</option></arg>
149
135
<command>&COMMANDNAME;</command>
150
<arg choice="plain"><option>--usage</option></arg>
136
<arg choice='plain'><option>--usage</option></arg>
153
139
<command>&COMMANDNAME;</command>
154
140
<group choice="req">
155
<arg choice="plain"><option>--version</option></arg>
156
<arg choice="plain"><option>-V</option></arg>
141
<arg choice='plain'><option>-V</option></arg>
142
<arg choice='plain'><option>--version</option></arg>
159
145
</refsynopsisdiv>
161
147
<refsect1 id="description">
162
148
<title>DESCRIPTION</title>
164
<command>&COMMANDNAME;</command> is a client program that
165
communicates with <citerefentry><refentrytitle
166
>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>
167
to get a password. In slightly more detail, this client program
168
brings up network interfaces, uses the interfaces’ IPv6
169
link-local addresses to get network connectivity, uses Zeroconf
170
to find servers on the local network, and communicates with
171
servers using TLS with a raw public key to ensure authenticity
172
and confidentiality. This client program keeps running, trying
173
all servers on the network, until it receives a satisfactory
174
reply or a TERM signal. After all servers have been tried, all
175
servers are periodically retried. If no servers are found it
176
will wait indefinitely for new servers to appear.
179
The network interfaces are selected like this: If any interfaces
180
are specified using the <option>--interface</option> option,
181
those interface are used. Otherwise,
182
<command>&COMMANDNAME;</command> will use all interfaces that
183
are not loopback interfaces, are not point-to-point interfaces,
184
are capable of broadcasting and do not have the NOARP flag (see
185
<citerefentry><refentrytitle>netdevice</refentrytitle>
186
<manvolnum>7</manvolnum></citerefentry>). (If the
187
<option>--connect</option> option is used, point-to-point
188
interfaces and non-broadcast interfaces are accepted.) If any
189
used interfaces are not up and running, they are first taken up
190
(and later taken down again on program exit).
193
Before network interfaces are selected, all <quote>network
194
hooks</quote> are run; see <xref linkend="network-hooks"/>.
197
This program is not meant to be run directly; it is really meant
198
to run as a plugin of the <application>Mandos</application>
199
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
200
<manvolnum>8mandos</manvolnum></citerefentry>, which runs in the
201
initial <acronym>RAM</acronym> disk environment because it is
202
specified as a <quote>keyscript</quote> in the <citerefentry>
203
<refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum>
204
</citerefentry> file.
208
<refsect1 id="purpose">
209
<title>PURPOSE</title>
211
The purpose of this is to enable <emphasis>remote and unattended
212
rebooting</emphasis> of client host computer with an
213
<emphasis>encrypted root file system</emphasis>. See <xref
214
linkend="overview"/> for details.
150
<command>&COMMANDNAME;</command> is a mandos plugin that works
151
like a client program that through avahi detects mandos servers,
152
sets up a gnutls connect and request a encrypted password. Any
153
passwords given is automaticly decrypted and passed to
218
158
<refsect1 id="options">
219
159
<title>OPTIONS</title>
221
This program is commonly not invoked from the command line; it
222
is normally started by the <application>Mandos</application>
223
plugin runner, see <citerefentry><refentrytitle
224
>plugin-runner</refentrytitle><manvolnum>8mandos</manvolnum>
225
</citerefentry>. Any command line options this program accepts
226
are therefore normally provided by the plugin runner, and not
161
Commonly not invoked as command lines but from configuration
162
file of plugin runner.
232
<term><option>--connect=<replaceable
233
>ADDRESS</replaceable><literal>:</literal><replaceable
234
>PORT</replaceable></option></term>
236
<replaceable>ADDRESS</replaceable><literal>:</literal
237
><replaceable>PORT</replaceable></option></term>
240
Do not use Zeroconf to locate servers. Connect directly
241
to only one specified <application>Mandos</application>
242
server. Note that an IPv6 address has colon characters in
243
it, so the <emphasis>last</emphasis> colon character is
244
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
255
<term><option>--interface=<replaceable
256
>NAME</replaceable><arg rep='repeat'>,<replaceable
257
>NAME</replaceable></arg></option></term>
259
<replaceable>NAME</replaceable><arg rep='repeat'>,<replaceable
260
>NAME</replaceable></arg></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.
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.
275
Note that since this program will normally run in the
276
initial RAM disk environment, the interface must be an
277
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"/>.
286
<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.
296
<term><option>--pubkey=<replaceable
297
>FILE</replaceable></option></term>
299
<replaceable>FILE</replaceable></option></term>
302
OpenPGP public key file name. The default name is
303
<quote><filename>/conf/conf.d/mandos/pubkey.txt</filename
310
<term><option>--seckey=<replaceable
311
>FILE</replaceable></option></term>
313
<replaceable>FILE</replaceable></option></term>
316
OpenPGP secret key file name. The default name is
317
<quote><filename>/conf/conf.d/mandos/seckey.txt</filename
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
<term><option>--priority=<replaceable
353
>STRING</replaceable></option></term>
355
<xi:include href="../mandos-options.xml"
356
xpointer="priority"/>
361
<term><option>--dh-bits=<replaceable
362
>BITS</replaceable></option></term>
365
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
393
<term><option>--delay=<replaceable
394
>SECONDS</replaceable></option></term>
397
After bringing a network interface up, the program waits
398
for the interface to arrive in a <quote>running</quote>
399
state before proceeding. During this time, the kernel log
400
level will be lowered to reduce clutter on the system
401
console, alleviating any other plugins which might be
402
using the system console. This option sets the upper
403
limit of seconds to wait. The default is 2.5 seconds.
409
<term><option>--retry=<replaceable
410
>SECONDS</replaceable></option></term>
413
All Mandos servers are tried repeatedly until a password
414
is received. This value specifies, in seconds, how long
415
between each successive try <emphasis>for the same
416
server</emphasis>. The default is 10 seconds.
422
<term><option>--network-hook-dir=<replaceable
423
>DIR</replaceable></option></term>
426
Network hook directory. The default directory is
427
<quote><filename class="directory"
428
>/lib/mandos/network-hooks.d</filename></quote>.
434
<term><option>--debug</option></term>
437
Enable debug mode. This will enable a lot of output to
438
standard error about what the program is doing. The
439
program will still perform all other functions normally.
442
It will also enable debug mode in the Avahi and GnuTLS
443
libraries, making them print large amounts of debugging
450
<term><option>--help</option></term>
451
<term><option>-?</option></term>
454
Gives a help message about options and their meanings.
460
<term><option>--usage</option></term>
463
Gives a short usage message.
469
<term><option>--version</option></term>
470
<term><option>-V</option></term>
473
Prints the program version.
167
<term><literal>-c</literal>, <literal>--connect=<replaceable>
168
IP</replaceable></literal></term>
171
Connect directly to a specified mandos server
177
<term><literal>-d</literal>, <literal>--keydir=<replaceable>
178
KEYDIR</replaceable></literal></term>
181
Directory where the openpgp keyring is
187
<term><literal>-i</literal>, <literal>--interface=
188
<replaceable>INTERFACE</replaceable></literal></term>
191
Interface that Avahi will conntect through
197
<term><literal>-p</literal>, <literal>--pubkey=<replaceable>
198
PUBKEY</replaceable></literal></term>
201
Public openpgp key for gnutls authentication
207
<term><literal>-s</literal>, <literal>--seckey=<replaceable>
208
SECKEY</replaceable></literal></term>
211
Secret openpgp key for gnutls authentication
217
<term><literal>--priority=<replaceable>PRIORITY</replaceable>
227
<term><literal>--dh-bits=<replaceable>BITS</replaceable>
231
dh-bits to use in gnutls communication
237
<term><literal>--debug</literal></term>
246
<term><literal>-?</literal>, <literal>--help</literal></term>
255
<term><literal>--usage</literal></term>
258
Gives a short usage message
264
<term><literal>-V</literal>, <literal>--version</literal></term>
267
Prints the program version
480
<refsect1 id="overview">
481
<title>OVERVIEW</title>
482
<xi:include href="../overview.xml"/>
484
This program is the client part. It is a plugin started by
485
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
486
<manvolnum>8mandos</manvolnum></citerefentry> which will run in
487
an initial <acronym>RAM</acronym> disk environment.
490
This program could, theoretically, be used as a keyscript in
491
<filename>/etc/crypttab</filename>, but it would then be
492
impossible to enter a password for the encrypted root disk at
493
the console, since this program does not read from the console
494
at all. This is why a separate plugin runner (<citerefentry>
495
<refentrytitle>plugin-runner</refentrytitle>
496
<manvolnum>8mandos</manvolnum></citerefentry>) is used to run
497
both this program and others in in parallel,
498
<emphasis>one</emphasis> of which (<citerefentry>
499
<refentrytitle>password-prompt</refentrytitle>
500
<manvolnum>8mandos</manvolnum></citerefentry>) will prompt for
501
passwords on the system console.
505
274
<refsect1 id="exit_status">
506
275
<title>EXIT STATUS</title>
508
This program will exit with a successful (zero) exit status if a
509
server could be found and the password received from it could be
510
successfully decrypted and output on standard output. The
511
program will exit with a non-zero exit status only if a critical
512
error occurs. Otherwise, it will forever connect to any
513
discovered <application>Mandos</application> servers, trying to
514
get a decryptable password and print it.
518
280
<refsect1 id="environment">
519
281
<title>ENVIRONMENT</title>
522
<term><envar>MANDOSPLUGINHELPERDIR</envar></term>
525
This environment variable will be assumed to contain the
526
directory containing any helper executables. The use and
527
nature of these helper executables, if any, is
528
purposefully not documented.
534
This program does not use any other environment variables, not
535
even the ones provided by <citerefentry><refentrytitle
536
>cryptsetup</refentrytitle><manvolnum>8</manvolnum>
541
<refsect1 id="network-hooks">
542
<title>NETWORK HOOKS</title>
544
If a network interface like a bridge or tunnel is required to
545
find a Mandos server, this requires the interface to be up and
546
running before <command>&COMMANDNAME;</command> starts looking
547
for Mandos servers. This can be accomplished by creating a
548
<quote>network hook</quote> program, and placing it in a special
552
Before the network is used (and again before program exit), any
553
runnable programs found in the network hook directory are run
554
with the argument <quote><literal>start</literal></quote> or
555
<quote><literal>stop</literal></quote>. This should bring up or
556
down, respectively, any network interface which
557
<command>&COMMANDNAME;</command> should use.
559
<refsect2 id="hook-requirements">
560
<title>REQUIREMENTS</title>
562
A network hook must be an executable file, and its name must
563
consist entirely of upper and lower case letters, digits,
564
underscores, periods, and hyphens.
567
A network hook will receive one argument, which can be one of
572
<term><literal>start</literal></term>
575
This should make the network hook create (if necessary)
576
and bring up a network interface.
581
<term><literal>stop</literal></term>
584
This should make the network hook take down a network
585
interface, and delete it if it did not exist previously.
590
<term><literal>files</literal></term>
593
This should make the network hook print, <emphasis>one
594
file per line</emphasis>, all the files needed for it to
595
run. (These files will be copied into the initial RAM
596
filesystem.) Typical use is for a network hook which is
597
a shell script to print its needed binaries.
600
It is not necessary to print any non-executable files
601
already in the network hook directory, these will be
602
copied implicitly if they otherwise satisfy the name
608
<term><literal>modules</literal></term>
611
This should make the network hook print, <emphasis>on
612
separate lines</emphasis>, all the kernel modules needed
613
for it to run. (These modules will be copied into the
614
initial RAM filesystem.) For instance, a tunnel
616
<quote><literal>tun</literal></quote> module.
622
The network hook will be provided with a number of environment
627
<term><envar>MANDOSNETHOOKDIR</envar></term>
630
The network hook directory, specified to
631
<command>&COMMANDNAME;</command> by the
632
<option>--network-hook-dir</option> option. Note: this
633
should <emphasis>always</emphasis> be used by the
634
network hook to refer to itself or any files in the hook
635
directory it may require.
640
<term><envar>DEVICE</envar></term>
643
The network interfaces, as specified to
644
<command>&COMMANDNAME;</command> by the
645
<option>--interface</option> option, combined to one
646
string and separated by commas. If this is set, and
647
does not contain the interface a hook will bring up,
648
there is no reason for a hook to continue.
653
<term><envar>MODE</envar></term>
656
This will be the same as the first argument;
657
i.e. <quote><literal>start</literal></quote>,
658
<quote><literal>stop</literal></quote>,
659
<quote><literal>files</literal></quote>, or
660
<quote><literal>modules</literal></quote>.
665
<term><envar>VERBOSITY</envar></term>
668
This will be the <quote><literal>1</literal></quote> if
669
the <option>--debug</option> option is passed to
670
<command>&COMMANDNAME;</command>, otherwise
671
<quote><literal>0</literal></quote>.
676
<term><envar>DELAY</envar></term>
679
This will be the same as the <option>--delay</option>
680
option passed to <command>&COMMANDNAME;</command>. Is
681
only set if <envar>MODE</envar> is
682
<quote><literal>start</literal></quote> or
683
<quote><literal>stop</literal></quote>.
688
<term><envar>CONNECT</envar></term>
691
This will be the same as the <option>--connect</option>
692
option passed to <command>&COMMANDNAME;</command>. Is
693
only set if <option>--connect</option> is passed and
694
<envar>MODE</envar> is
695
<quote><literal>start</literal></quote> or
696
<quote><literal>stop</literal></quote>.
702
A hook may not read from standard input, and should be
703
restrictive in printing to standard output or standard error
704
unless <varname>VERBOSITY</varname> is
705
<quote><literal>1</literal></quote>.
710
<refsect1 id="files">
711
287
<title>FILES</title>
714
<term><filename>/conf/conf.d/mandos/pubkey.txt</filename
716
<term><filename>/conf/conf.d/mandos/seckey.txt</filename
720
OpenPGP public and private key files, in <quote>ASCII
721
Armor</quote> format. These are the default file names,
722
they can be changed with the <option>--pubkey</option> and
723
<option>--seckey</option> options.
728
<term><filename>/conf/conf.d/mandos/tls-pubkey.pem</filename
730
<term><filename>/conf/conf.d/mandos/tls-privkey.pem</filename
734
Public and private raw key files, in <quote>PEM</quote>
735
format. These are the default file names, they can be
736
changed with the <option>--tls-pubkey</option> and
737
<option>--tls-privkey</option> options.
743
class="directory">/lib/mandos/network-hooks.d</filename></term>
746
Directory where network hooks are located. Change this
747
with the <option>--network-hook-dir</option> option. See
748
<xref linkend="network-hooks"/>.
755
292
<refsect1 id="bugs">
756
293
<title>BUGS</title>
757
<xi:include href="../bugs.xml"/>
760
298
<refsect1 id="example">
761
299
<title>EXAMPLE</title>
763
Note that normally, command line options will not be given
764
directly, but via options for the Mandos <citerefentry
765
><refentrytitle>plugin-runner</refentrytitle>
766
<manvolnum>8mandos</manvolnum></citerefentry>.
770
Normal invocation needs no options, if the network interfaces
771
can be automatically determined:
774
<userinput>&COMMANDNAME;</userinput>
779
Search for Mandos servers (and connect to them) using one
783
<!-- do not wrap this line -->
784
<userinput>&COMMANDNAME; --interface eth1</userinput>
789
Run in debug mode, and use custom keys:
793
<!-- do not wrap this line -->
794
<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt --tls-pubkey keydir/tls-pubkey.pem --tls-privkey keydir/tls-privkey.pem</userinput>
800
Run in debug mode, with custom keys, and do not use Zeroconf
801
to locate a server; connect directly to the IPv6 link-local
802
address <quote><systemitem class="ipaddress"
803
>fe80::aede:48ff:fe71:f6f2</systemitem></quote>, port 4711,
804
using interface eth2:
808
<!-- do not wrap this line -->
809
<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt --tls-pubkey keydir/tls-pubkey.pem --tls-privkey keydir/tls-privkey.pem --connect fe80::aede:48ff:fe71:f6f2:4711 --interface eth2</userinput>
815
304
<refsect1 id="security">
816
305
<title>SECURITY</title>
818
This program is set-uid to root, but will switch back to the
819
original (and presumably non-privileged) user and group after
820
bringing up the network interface.
823
To use this program for its intended purpose (see <xref
824
linkend="purpose"/>), the password for the root file system will
825
have to be given out to be stored in a server computer, after
826
having been encrypted using an OpenPGP key. This encrypted data
827
which will be stored in a server can only be decrypted by the
828
OpenPGP key, and the data will only be given out to those
829
clients who can prove they actually have that key. This key,
830
however, is stored unencrypted on the client side in its initial
831
<acronym>RAM</acronym> disk image file system. This is normally
832
readable by all, but this is normally fixed during installation
833
of this program; file permissions are set so that no-one is able
837
The only remaining weak point is that someone with physical
838
access to the client hard drive might turn off the client
839
computer, read the OpenPGP and TLS keys directly from the hard
840
drive, and communicate with the server. To safeguard against
841
this, the server is supposed to notice the client disappearing
842
and stop giving out the encrypted data. Therefore, it is
843
important to set the timeout and checker interval values tightly
844
on the server. See <citerefentry><refentrytitle
845
>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
848
It will also help if the checker program on the server is
849
configured to request something from the client which can not be
850
spoofed by someone else on the network, like SSH server key
851
fingerprints, and unlike unencrypted <acronym>ICMP</acronym>
852
echo (<quote>ping</quote>) replies.
855
<emphasis>Note</emphasis>: This makes it completely insecure to
856
have <application >Mandos</application> clients which dual-boot
857
to another operating system which is <emphasis>not</emphasis>
858
trusted to keep the initial <acronym>RAM</acronym> disk image
863
310
<refsect1 id="see_also">
864
311
<title>SEE ALSO</title>
866
<citerefentry><refentrytitle>intro</refentrytitle>
867
<manvolnum>8mandos</manvolnum></citerefentry>,
868
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
869
<manvolnum>8</manvolnum></citerefentry>,
870
<citerefentry><refentrytitle>crypttab</refentrytitle>
871
<manvolnum>5</manvolnum></citerefentry>,
872
313
<citerefentry><refentrytitle>mandos</refentrytitle>
873
314
<manvolnum>8</manvolnum></citerefentry>,
874
315
<citerefentry><refentrytitle>password-prompt</refentrytitle>