96
<option>--delay <replaceable>SECONDS</replaceable></option>
124
100
<option>--debug</option>
128
104
<command>&COMMANDNAME;</command>
129
105
<group choice="req">
130
<arg choice='plain'><option>-?</option></arg>
131
<arg choice='plain'><option>--help</option></arg>
106
<arg choice="plain"><option>--help</option></arg>
107
<arg choice="plain"><option>-?</option></arg>
135
111
<command>&COMMANDNAME;</command>
136
<arg choice='plain'><option>--usage</option></arg>
112
<arg choice="plain"><option>--usage</option></arg>
139
115
<command>&COMMANDNAME;</command>
140
116
<group choice="req">
141
<arg choice='plain'><option>-V</option></arg>
142
<arg choice='plain'><option>--version</option></arg>
117
<arg choice="plain"><option>--version</option></arg>
118
<arg choice="plain"><option>-V</option></arg>
145
121
</refsynopsisdiv>
147
123
<refsect1 id="description">
148
124
<title>DESCRIPTION</title>
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
126
<command>&COMMANDNAME;</command> is a client program that
127
communicates with <citerefentry><refentrytitle
128
>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>
129
to get a password. In slightly more detail, this client program
130
brings up a network interface, uses the interface’s IPv6
131
link-local address to get network connectivity, uses Zeroconf to
132
find servers on the local network, and communicates with servers
133
using TLS with an OpenPGP key to ensure authenticity and
134
confidentiality. This client program keeps running, trying all
135
servers on the network, until it receives a satisfactory reply
136
or a TERM signal is received. If no servers are found, or after
137
all servers have been tried, it waits indefinitely for new
141
This program is not meant to be run directly; it is really meant
142
to run as a plugin of the <application>Mandos</application>
143
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
144
<manvolnum>8mandos</manvolnum></citerefentry>, which runs in the
145
initial <acronym>RAM</acronym> disk environment because it is
146
specified as a <quote>keyscript</quote> in the <citerefentry>
147
<refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum>
148
</citerefentry> file.
152
<refsect1 id="purpose">
153
<title>PURPOSE</title>
155
The purpose of this is to enable <emphasis>remote and unattended
156
rebooting</emphasis> of client host computer with an
157
<emphasis>encrypted root file system</emphasis>. See <xref
158
linkend="overview"/> for details.
158
162
<refsect1 id="options">
159
163
<title>OPTIONS</title>
161
Commonly not invoked as command lines but from configuration
162
file of plugin runner.
165
This program is commonly not invoked from the command line; it
166
is normally started by the <application>Mandos</application>
167
plugin runner, see <citerefentry><refentrytitle
168
>plugin-runner</refentrytitle><manvolnum>8mandos</manvolnum>
169
</citerefentry>. Any command line options this program accepts
170
are therefore normally provided by the plugin runner, and not
167
<term><literal>-c</literal>, <literal>--connect=<replaceable>
168
IP</replaceable></literal></term>
171
Connect directly to a specified mandos server
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<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
176
<term><option>--connect=<replaceable
177
>ADDRESS</replaceable><literal>:</literal><replaceable
178
>PORT</replaceable></option></term>
180
<replaceable>ADDRESS</replaceable><literal>:</literal
181
><replaceable>PORT</replaceable></option></term>
184
Do not use Zeroconf to locate servers. Connect directly
185
to only one specified <application>Mandos</application>
186
server. Note that an IPv6 address has colon characters in
187
it, so the <emphasis>last</emphasis> colon character is
188
assumed to separate the address from the port number.
191
This option is normally only useful for testing and
198
<term><option>--interface=<replaceable
199
>NAME</replaceable></option></term>
201
<replaceable>NAME</replaceable></option></term>
204
Network interface that will be brought up and scanned for
205
Mandos servers to connect to. The default is
206
<quote><literal>eth0</literal></quote>.
209
If the <option>--connect</option> option is used, this
210
specifies the interface to use to connect to the address
214
Note that since this program will normally run in the
215
initial RAM disk environment, the interface must be an
216
interface which exists at that stage. Thus, the interface
217
can not be a pseudo-interface such as <quote>br0</quote>
218
or <quote>tun0</quote>; such interfaces will not exist
219
until much later in the boot process, and can not be used
223
<replaceable>NAME</replaceable> can be the empty string;
224
this will not use any specific interface, and will not
225
bring up an interface on startup. This is not
226
recommended, and only meant for advanced users.
232
<term><option>--pubkey=<replaceable
233
>FILE</replaceable></option></term>
235
<replaceable>FILE</replaceable></option></term>
238
OpenPGP public key file name. The default name is
239
<quote><filename>/conf/conf.d/mandos/pubkey.txt</filename
246
<term><option>--seckey=<replaceable
247
>FILE</replaceable></option></term>
249
<replaceable>FILE</replaceable></option></term>
252
OpenPGP secret key file name. The default name is
253
<quote><filename>/conf/conf.d/mandos/seckey.txt</filename
260
<term><option>--priority=<replaceable
261
>STRING</replaceable></option></term>
263
<xi:include href="../mandos-options.xml"
264
xpointer="priority"/>
269
<term><option>--dh-bits=<replaceable
270
>BITS</replaceable></option></term>
273
Sets the number of bits to use for the prime number in the
274
TLS Diffie-Hellman key exchange. Default is 1024.
280
<term><option>--delay=<replaceable
281
>SECONDS</replaceable></option></term>
284
After bringing the network interface up, the program waits
285
for the interface to arrive in a <quote>running</quote>
286
state before proceeding. During this time, the kernel log
287
level will be lowered to reduce clutter on the system
288
console, alleviating any other plugins which might be
289
using the system console. This option sets the upper
290
limit of seconds to wait. The default is 2.5 seconds.
296
<term><option>--debug</option></term>
299
Enable debug mode. This will enable a lot of output to
300
standard error about what the program is doing. The
301
program will still perform all other functions normally.
304
It will also enable debug mode in the Avahi and GnuTLS
305
libraries, making them print large amounts of debugging
312
<term><option>--help</option></term>
313
<term><option>-?</option></term>
316
Gives a help message about options and their meanings.
322
<term><option>--usage</option></term>
325
Gives a short usage message.
331
<term><option>--version</option></term>
332
<term><option>-V</option></term>
335
Prints the program version.
342
<refsect1 id="overview">
343
<title>OVERVIEW</title>
344
<xi:include href="../overview.xml"/>
346
This program is the client part. It is a plugin started by
347
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
348
<manvolnum>8mandos</manvolnum></citerefentry> which will run in
349
an initial <acronym>RAM</acronym> disk environment.
352
This program could, theoretically, be used as a keyscript in
353
<filename>/etc/crypttab</filename>, but it would then be
354
impossible to enter a password for the encrypted root disk at
355
the console, since this program does not read from the console
356
at all. This is why a separate plugin runner (<citerefentry>
357
<refentrytitle>plugin-runner</refentrytitle>
358
<manvolnum>8mandos</manvolnum></citerefentry>) is used to run
359
both this program and others in in parallel,
360
<emphasis>one</emphasis> of which will prompt for passwords on
274
365
<refsect1 id="exit_status">
275
366
<title>EXIT STATUS</title>
368
This program will exit with a successful (zero) exit status if a
369
server could be found and the password received from it could be
370
successfully decrypted and output on standard output. The
371
program will exit with a non-zero exit status only if a critical
372
error occurs. Otherwise, it will forever connect to new
373
<application>Mandos</application> servers as they appear, trying
374
to get a decryptable password and print it.
280
378
<refsect1 id="environment">
281
379
<title>ENVIRONMENT</title>
381
This program does not use any environment variables, not even
382
the ones provided by <citerefentry><refentrytitle
383
>cryptsetup</refentrytitle><manvolnum>8</manvolnum>
388
<refsect1 id="files">
287
389
<title>FILES</title>
392
<term><filename>/conf/conf.d/mandos/pubkey.txt</filename
394
<term><filename>/conf/conf.d/mandos/seckey.txt</filename
398
OpenPGP public and private key files, in <quote>ASCII
399
Armor</quote> format. These are the default file names,
400
they can be changed with the <option>--pubkey</option> and
401
<option>--seckey</option> options.
408
<!-- <refsect1 id="bugs"> -->
409
<!-- <title>BUGS</title> -->
298
414
<refsect1 id="example">
299
415
<title>EXAMPLE</title>
417
Note that normally, command line options will not be given
418
directly, but via options for the Mandos <citerefentry
419
><refentrytitle>plugin-runner</refentrytitle>
420
<manvolnum>8mandos</manvolnum></citerefentry>.
424
Normal invocation needs no options, if the network interface
425
is <quote>eth0</quote>:
428
<userinput>&COMMANDNAME;</userinput>
433
Search for Mandos servers (and connect to them) using another
437
<!-- do not wrap this line -->
438
<userinput>&COMMANDNAME; --interface eth1</userinput>
443
Run in debug mode, and use a custom key:
447
<!-- do not wrap this line -->
448
<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt</userinput>
454
Run in debug mode, with a custom key, and do not use Zeroconf
455
to locate a server; connect directly to the IPv6 link-local
456
address <quote><systemitem class="ipaddress"
457
>fe80::aede:48ff:fe71:f6f2</systemitem></quote>, port 4711,
458
using interface eth2:
462
<!-- do not wrap this line -->
463
<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt --connect fe80::aede:48ff:fe71:f6f2:4711 --interface eth2</userinput>
304
469
<refsect1 id="security">
305
470
<title>SECURITY</title>
472
This program is set-uid to root, but will switch back to the
473
original (and presumably non-privileged) user and group after
474
bringing up the network interface.
477
To use this program for its intended purpose (see <xref
478
linkend="purpose"/>), the password for the root file system will
479
have to be given out to be stored in a server computer, after
480
having been encrypted using an OpenPGP key. This encrypted data
481
which will be stored in a server can only be decrypted by the
482
OpenPGP key, and the data will only be given out to those
483
clients who can prove they actually have that key. This key,
484
however, is stored unencrypted on the client side in its initial
485
<acronym>RAM</acronym> disk image file system. This is normally
486
readable by all, but this is normally fixed during installation
487
of this program; file permissions are set so that no-one is able
491
The only remaining weak point is that someone with physical
492
access to the client hard drive might turn off the client
493
computer, read the OpenPGP keys directly from the hard drive,
494
and communicate with the server. To safeguard against this, the
495
server is supposed to notice the client disappearing and stop
496
giving out the encrypted data. Therefore, it is important to
497
set the timeout and checker interval values tightly on the
498
server. See <citerefentry><refentrytitle
499
>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
502
It will also help if the checker program on the server is
503
configured to request something from the client which can not be
504
spoofed by someone else on the network, unlike unencrypted
505
<acronym>ICMP</acronym> echo (<quote>ping</quote>) replies.
508
<emphasis>Note</emphasis>: This makes it completely insecure to
509
have <application >Mandos</application> clients which dual-boot
510
to another operating system which is <emphasis>not</emphasis>
511
trusted to keep the initial <acronym>RAM</acronym> disk image
310
516
<refsect1 id="see_also">
311
517
<title>SEE ALSO</title>
519
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
520
<manvolnum>8</manvolnum></citerefentry>,
521
<citerefentry><refentrytitle>crypttab</refentrytitle>
522
<manvolnum>5</manvolnum></citerefentry>,
313
523
<citerefentry><refentrytitle>mandos</refentrytitle>
314
524
<manvolnum>8</manvolnum></citerefentry>,
315
525
<citerefentry><refentrytitle>password-prompt</refentrytitle>