69
46
<refname><command>&COMMANDNAME;</command></refname>
48
Client for <application>Mandos</application>
77
54
<command>&COMMANDNAME;</command>
78
<arg choice='opt'>--connect<arg choice='plain'>IP</arg></arg>
79
<arg choice='opt'>--keydir<arg choice='plain'>KEYDIR</arg></arg>
80
<arg choice='opt'>--interface<arg choice='plain'>INTERFACE</arg></arg>
81
<arg choice='opt'>--pubkey<arg choice='plain'>PUBKEY</arg></arg>
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<arg choice='opt'>--seckey<arg choice='plain'>SECKEY</arg></arg>
83
<arg choice='opt'>--priority<arg choice='plain'>PRIORITY</arg></arg>
84
<arg choice='opt'>--dh-bits<arg choice='plain'>BITS</arg></arg>
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<arg choice='opt'>--debug</arg>
88
<command>&COMMANDNAME;</command>
89
<arg choice='plain'>--help</arg>
92
<command>&COMMANDNAME;</command>
93
<arg choice='plain'>--usage</arg>
96
<command>&COMMANDNAME;</command>
97
<arg choice='plain'>--version</arg>
56
<arg choice="plain"><option>--connect
57
<replaceable>ADDRESS</replaceable><literal>:</literal
58
><replaceable>PORT</replaceable></option></arg>
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<arg choice="plain"><option>-c
60
<replaceable>ADDRESS</replaceable><literal>:</literal
61
><replaceable>PORT</replaceable></option></arg>
65
<arg choice="plain"><option>--interface
66
<replaceable>NAME</replaceable></option></arg>
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<arg choice="plain"><option>-i
68
<replaceable>NAME</replaceable></option></arg>
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<arg choice="plain"><option>--pubkey
73
<replaceable>FILE</replaceable></option></arg>
74
<arg choice="plain"><option>-p
75
<replaceable>FILE</replaceable></option></arg>
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<arg choice="plain"><option>--seckey
80
<replaceable>FILE</replaceable></option></arg>
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<arg choice="plain"><option>-s
82
<replaceable>FILE</replaceable></option></arg>
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<option>--priority <replaceable>STRING</replaceable></option>
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<option>--dh-bits <replaceable>BITS</replaceable></option>
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<option>--debug</option>
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<command>&COMMANDNAME;</command>
100
<arg choice="plain"><option>--help</option></arg>
101
<arg choice="plain"><option>-?</option></arg>
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<command>&COMMANDNAME;</command>
106
<arg choice="plain"><option>--usage</option></arg>
109
<command>&COMMANDNAME;</command>
111
<arg choice="plain"><option>--version</option></arg>
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<arg choice="plain"><option>-V</option></arg>
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117
<refsect1 id="description">
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118
<title>DESCRIPTION</title>
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<command>&COMMANDNAME;</command> is a mandos plugin that works
105
like a client program that through avahi detects mandos servers,
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sets up a gnutls connect and request a encrypted password. Any
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passwords given is automaticly decrypted and passed to
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<command>&COMMANDNAME;</command> is a client program that
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communicates with <citerefentry><refentrytitle
122
>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>
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to get a password. It uses IPv6 link-local addresses to get
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network connectivity, Zeroconf to find servers, and TLS with an
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OpenPGP key to ensure authenticity and confidentiality. It
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keeps running, trying all servers on the network, until it
127
receives a satisfactory reply or a TERM signal is received.
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This program is not meant to be run directly; it is really meant
131
to run as a plugin of the <application>Mandos</application>
132
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
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<manvolnum>8mandos</manvolnum></citerefentry>, which runs in the
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initial <acronym>RAM</acronym> disk environment because it is
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specified as a <quote>keyscript</quote> in the <citerefentry>
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<refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum>
137
</citerefentry> file.
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<refsect1 id="purpose">
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<title>PURPOSE</title>
144
The purpose of this is to enable <emphasis>remote and unattended
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rebooting</emphasis> of client host computer with an
146
<emphasis>encrypted root file system</emphasis>. See <xref
147
linkend="overview"/> for details.
112
151
<refsect1 id="options">
113
152
<title>OPTIONS</title>
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Commonly not invoked as command lines but from configuration
116
file of plugin runner.
154
This program is commonly not invoked from the command line; it
155
is normally started by the <application>Mandos</application>
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plugin runner, see <citerefentry><refentrytitle
157
>plugin-runner</refentrytitle><manvolnum>8mandos</manvolnum>
158
</citerefentry>. Any command line options this program accepts
159
are therefore normally provided by the plugin runner, and not
121
<term><literal>-c</literal>, <literal>--connect=<replaceable>
122
IP</replaceable></literal></term>
125
Connect directly to a specified mandos server
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<term><literal>-d</literal>, <literal>--keydir=<replaceable>
132
KEYDIR</replaceable></literal></term>
135
Directory where the openpgp keyring is
141
<term><literal>-i</literal>, <literal>--interface=
142
<replaceable>INTERFACE</replaceable></literal></term>
145
Interface that Avahi will conntect through
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<term><literal>-p</literal>, <literal>--pubkey=<replaceable>
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PUBKEY</replaceable></literal></term>
155
Public openpgp key for gnutls authentication
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<term><literal>-s</literal>, <literal>--seckey=<replaceable>
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SECKEY</replaceable></literal></term>
165
Secret openpgp key for gnutls authentication
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<term><literal>--priority=<replaceable>PRIORITY</replaceable>
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<term><literal>--dh-bits=<replaceable>BITS</replaceable>
185
dh-bits to use in gnutls communication
191
<term><literal>--debug</literal></term>
200
<term><literal>-?</literal>, <literal>--help</literal></term>
209
<term><literal>--usage</literal></term>
212
Gives a short usage message
218
<term><literal>-V</literal>, <literal>--version</literal></term>
221
Prints the program version
165
<term><option>--connect=<replaceable
166
>ADDRESS</replaceable><literal>:</literal><replaceable
167
>PORT</replaceable></option></term>
169
<replaceable>ADDRESS</replaceable><literal>:</literal
170
><replaceable>PORT</replaceable></option></term>
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Do not use Zeroconf to locate servers. Connect directly
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to only one specified <application>Mandos</application>
175
server. Note that an IPv6 address has colon characters in
176
it, so the <emphasis>last</emphasis> colon character is
177
assumed to separate the address from the port number.
180
This option is normally only useful for testing and
187
<term><option>--interface=
188
<replaceable>NAME</replaceable></option></term>
190
<replaceable>NAME</replaceable></option></term>
193
Network interface that will be brought up and scanned for
194
Mandos servers to connect to. The default it
195
<quote><literal>eth0</literal></quote>.
198
If the <option>--connect</option> option is used, this
199
specifies the interface to use to connect to the address
206
<term><option>--pubkey=<replaceable
207
>FILE</replaceable></option></term>
209
<replaceable>FILE</replaceable></option></term>
212
OpenPGP public key file name. The default name is
213
<quote><filename>/conf/conf.d/mandos/pubkey.txt</filename
220
<term><option>--seckey=<replaceable
221
>FILE</replaceable></option></term>
223
<replaceable>FILE</replaceable></option></term>
226
OpenPGP secret key file name. The default name is
227
<quote><filename>/conf/conf.d/mandos/seckey.txt</filename
234
<term><option>--priority=<replaceable
235
>STRING</replaceable></option></term>
237
<xi:include href="../mandos-options.xml"
238
xpointer="priority"/>
243
<term><option>--dh-bits=<replaceable
244
>BITS</replaceable></option></term>
247
Sets the number of bits to use for the prime number in the
248
TLS Diffie-Hellman key exchange. Default is 1024.
254
<term><option>--debug</option></term>
257
Enable debug mode. This will enable a lot of output to
258
standard error about what the program is doing. The
259
program will still perform all other functions normally.
262
It will also enable debug mode in the Avahi and GnuTLS
263
libraries, making them print large amounts of debugging
270
<term><option>--help</option></term>
271
<term><option>-?</option></term>
274
Gives a help message about options and their meanings.
280
<term><option>--usage</option></term>
283
Gives a short usage message.
289
<term><option>--version</option></term>
290
<term><option>-V</option></term>
293
Prints the program version.
300
<refsect1 id="overview">
301
<title>OVERVIEW</title>
302
<xi:include href="../overview.xml"/>
304
This program is the client part. It is a plugin started by
305
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
306
<manvolnum>8mandos</manvolnum></citerefentry> which will run in
307
an initial <acronym>RAM</acronym> disk environment.
310
This program could, theoretically, be used as a keyscript in
311
<filename>/etc/crypttab</filename>, but it would then be
312
impossible to enter a password for the encrypted root disk at
313
the console, since this program does not read from the console
314
at all. This is why a separate plugin runner (<citerefentry>
315
<refentrytitle>plugin-runner</refentrytitle>
316
<manvolnum>8mandos</manvolnum></citerefentry>) is used to run
317
both this program and others in in parallel,
318
<emphasis>one</emphasis> of which will prompt for passwords on
228
323
<refsect1 id="exit_status">
229
324
<title>EXIT STATUS</title>
326
This program will exit with a successful (zero) exit status if a
327
server could be found and the password received from it could be
328
successfully decrypted and output on standard output. The
329
program will exit with a non-zero exit status only if a critical
330
error occurs. Otherwise, it will forever connect to new
331
<application>Mandos</application> servers as they appear, trying
332
to get a decryptable password and print it.
234
336
<refsect1 id="environment">
235
337
<title>ENVIRONMENT</title>
339
This program does not use any environment variables, not even
340
the ones provided by <citerefentry><refentrytitle
341
>cryptsetup</refentrytitle><manvolnum>8</manvolnum>
240
346
<refsect1 id="file">
241
347
<title>FILES</title>
350
<term><filename>/conf/conf.d/mandos/pubkey.txt</filename
352
<term><filename>/conf/conf.d/mandos/seckey.txt</filename
356
OpenPGP public and private key files, in <quote>ASCII
357
Armor</quote> format. These are the default file names,
358
they can be changed with the <option>--pubkey</option> and
359
<option>--seckey</option> options.
366
<!-- <refsect1 id="bugs"> -->
367
<!-- <title>BUGS</title> -->
252
372
<refsect1 id="example">
253
373
<title>EXAMPLE</title>
375
Note that normally, command line options will not be given
376
directly, but via options for the Mandos <citerefentry
377
><refentrytitle>plugin-runner</refentrytitle>
378
<manvolnum>8mandos</manvolnum></citerefentry>.
382
Normal invocation needs no options, if the network interface
383
is <quote>eth0</quote>:
386
<userinput>&COMMANDNAME;</userinput>
391
Search for Mandos servers (and connect to them) using another
395
<!-- do not wrap this line -->
396
<userinput>&COMMANDNAME; --interface eth1</userinput>
401
Run in debug mode, and use a custom key:
405
<!-- do not wrap this line -->
406
<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt</userinput>
412
Run in debug mode, with a custom key, and do not use Zeroconf
413
to locate a server; connect directly to the IPv6 address
414
<quote><systemitem class="ipaddress"
415
>2001:db8:f983:bd0b:30de:ae4a:71f2:f672</systemitem></quote>,
416
port 4711, using interface eth2:
420
<!-- do not wrap this line -->
421
<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt --connect 2001:db8:f983:bd0b:30de:ae4a:71f2:f672:4711 --interface eth2</userinput>
258
427
<refsect1 id="security">
259
428
<title>SECURITY</title>
430
This program is set-uid to root, but will switch back to the
431
original (and presumably non-privileged) user and group after
432
bringing up the network interface.
435
To use this program for its intended purpose (see <xref
436
linkend="purpose"/>), the password for the root file system will
437
have to be given out to be stored in a server computer, after
438
having been encrypted using an OpenPGP key. This encrypted data
439
which will be stored in a server can only be decrypted by the
440
OpenPGP key, and the data will only be given out to those
441
clients who can prove they actually have that key. This key,
442
however, is stored unencrypted on the client side in its initial
443
<acronym>RAM</acronym> disk image file system. This is normally
444
readable by all, but this is normally fixed during installation
445
of this program; file permissions are set so that no-one is able
449
The only remaining weak point is that someone with physical
450
access to the client hard drive might turn off the client
451
computer, read the OpenPGP keys directly from the hard drive,
452
and communicate with the server. To safeguard against this, the
453
server is supposed to notice the client disappearing and stop
454
giving out the encrypted data. Therefore, it is important to
455
set the timeout and checker interval values tightly on the
456
server. See <citerefentry><refentrytitle
457
>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
460
It will also help if the checker program on the server is
461
configured to request something from the client which can not be
462
spoofed by someone else on the network, unlike unencrypted
463
<acronym>ICMP</acronym> echo (<quote>ping</quote>) replies.
466
<emphasis>Note</emphasis>: This makes it completely insecure to
467
have <application >Mandos</application> clients which dual-boot
468
to another operating system which is <emphasis>not</emphasis>
469
trusted to keep the initial <acronym>RAM</acronym> disk image
264
474
<refsect1 id="see_also">
265
475
<title>SEE ALSO</title>
477
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
478
<manvolnum>8</manvolnum></citerefentry>,
479
<citerefentry><refentrytitle>crypttab</refentrytitle>
480
<manvolnum>5</manvolnum></citerefentry>,
267
481
<citerefentry><refentrytitle>mandos</refentrytitle>
268
482
<manvolnum>8</manvolnum></citerefentry>,
269
483
<citerefentry><refentrytitle>password-prompt</refentrytitle>