69
47
<refname><command>&COMMANDNAME;</command></refname>
49
Client for <application>Mandos</application>
77
55
<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>
82
<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>
85
<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>
57
<arg choice="plain"><option>--connect
58
<replaceable>ADDRESS</replaceable><literal>:</literal
59
><replaceable>PORT</replaceable></option></arg>
60
<arg choice="plain"><option>-c
61
<replaceable>ADDRESS</replaceable><literal>:</literal
62
><replaceable>PORT</replaceable></option></arg>
66
<arg choice="plain"><option>--interface
67
<replaceable>NAME</replaceable></option></arg>
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<arg choice="plain"><option>-i
69
<replaceable>NAME</replaceable></option></arg>
73
<arg choice="plain"><option>--pubkey
74
<replaceable>FILE</replaceable></option></arg>
75
<arg choice="plain"><option>-p
76
<replaceable>FILE</replaceable></option></arg>
80
<arg choice="plain"><option>--seckey
81
<replaceable>FILE</replaceable></option></arg>
82
<arg choice="plain"><option>-s
83
<replaceable>FILE</replaceable></option></arg>
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<option>--priority <replaceable>STRING</replaceable></option>
91
<option>--dh-bits <replaceable>BITS</replaceable></option>
95
<option>--debug</option>
99
<command>&COMMANDNAME;</command>
101
<arg choice="plain"><option>--help</option></arg>
102
<arg choice="plain"><option>-?</option></arg>
106
<command>&COMMANDNAME;</command>
107
<arg choice="plain"><option>--usage</option></arg>
110
<command>&COMMANDNAME;</command>
112
<arg choice="plain"><option>--version</option></arg>
113
<arg choice="plain"><option>-V</option></arg>
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118
<refsect1 id="description">
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119
<title>DESCRIPTION</title>
104
<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
122
communicates with <citerefentry><refentrytitle
123
>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>
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to get a password. It uses IPv6 link-local addresses to get
125
network connectivity, Zeroconf to find servers, and TLS with an
126
OpenPGP key to ensure authenticity and confidentiality. It
127
keeps running, trying all servers on the network, until it
128
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
132
to run as a plugin of the <application>Mandos</application>
133
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
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<manvolnum>8mandos</manvolnum></citerefentry>, which runs in the
135
initial <acronym>RAM</acronym> disk environment because it is
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specified as a <quote>keyscript</quote> in the <citerefentry>
137
<refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum>
138
</citerefentry> file.
142
<refsect1 id="purpose">
143
<title>PURPOSE</title>
145
The purpose of this is to enable <emphasis>remote and unattended
146
rebooting</emphasis> of client host computer with an
147
<emphasis>encrypted root file system</emphasis>. See <xref
148
linkend="overview"/> for details.
112
152
<refsect1 id="options">
113
153
<title>OPTIONS</title>
115
Commonly not invoked as command lines but from configuration
116
file of plugin runner.
155
This program is commonly not invoked from the command line; it
156
is normally started by the <application>Mandos</application>
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plugin runner, see <citerefentry><refentrytitle
158
>plugin-runner</refentrytitle><manvolnum>8mandos</manvolnum>
159
</citerefentry>. Any command line options this program accepts
160
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
131
<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
151
<term><literal>-p</literal>, <literal>--pubkey=<replaceable>
152
PUBKEY</replaceable></literal></term>
155
Public openpgp key for gnutls authentication
161
<term><literal>-s</literal>, <literal>--seckey=<replaceable>
162
SECKEY</replaceable></literal></term>
165
Secret openpgp key for gnutls authentication
171
<term><literal>--priority=<replaceable>PRIORITY</replaceable>
181
<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
166
<term><option>--connect=<replaceable
167
>ADDRESS</replaceable><literal>:</literal><replaceable
168
>PORT</replaceable></option></term>
170
<replaceable>ADDRESS</replaceable><literal>:</literal
171
><replaceable>PORT</replaceable></option></term>
174
Do not use Zeroconf to locate servers. Connect directly
175
to only one specified <application>Mandos</application>
176
server. Note that an IPv6 address has colon characters in
177
it, so the <emphasis>last</emphasis> colon character is
178
assumed to separate the address from the port number.
181
This option is normally only useful for testing and
188
<term><option>--interface=
189
<replaceable>NAME</replaceable></option></term>
191
<replaceable>NAME</replaceable></option></term>
194
Network interface that will be brought up and scanned for
195
Mandos servers to connect to. The default it
196
<quote><literal>eth0</literal></quote>.
199
If the <option>--connect</option> option is used, this
200
specifies the interface to use to connect to the address
207
<term><option>--pubkey=<replaceable
208
>FILE</replaceable></option></term>
210
<replaceable>FILE</replaceable></option></term>
213
OpenPGP public key file name. The default name is
214
<quote><filename>/conf/conf.d/mandos/pubkey.txt</filename
221
<term><option>--seckey=<replaceable
222
>FILE</replaceable></option></term>
224
<replaceable>FILE</replaceable></option></term>
227
OpenPGP secret key file name. The default name is
228
<quote><filename>/conf/conf.d/mandos/seckey.txt</filename
235
<term><option>--priority=<replaceable
236
>STRING</replaceable></option></term>
238
<xi:include href="../mandos-options.xml"
239
xpointer="priority"/>
244
<term><option>--dh-bits=<replaceable
245
>BITS</replaceable></option></term>
248
Sets the number of bits to use for the prime number in the
249
TLS Diffie-Hellman key exchange. Default is 1024.
255
<term><option>--debug</option></term>
258
Enable debug mode. This will enable a lot of output to
259
standard error about what the program is doing. The
260
program will still perform all other functions normally.
263
It will also enable debug mode in the Avahi and GnuTLS
264
libraries, making them print large amounts of debugging
271
<term><option>--help</option></term>
272
<term><option>-?</option></term>
275
Gives a help message about options and their meanings.
281
<term><option>--usage</option></term>
284
Gives a short usage message.
290
<term><option>--version</option></term>
291
<term><option>-V</option></term>
294
Prints the program version.
301
<refsect1 id="overview">
302
<title>OVERVIEW</title>
303
<xi:include href="../overview.xml"/>
305
This program is the client part. It is a plugin started by
306
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
307
<manvolnum>8mandos</manvolnum></citerefentry> which will run in
308
an initial <acronym>RAM</acronym> disk environment.
311
This program could, theoretically, be used as a keyscript in
312
<filename>/etc/crypttab</filename>, but it would then be
313
impossible to enter a password for the encrypted root disk at
314
the console, since this program does not read from the console
315
at all. This is why a separate plugin runner (<citerefentry>
316
<refentrytitle>plugin-runner</refentrytitle>
317
<manvolnum>8mandos</manvolnum></citerefentry>) is used to run
318
both this program and others in in parallel,
319
<emphasis>one</emphasis> of which will prompt for passwords on
228
324
<refsect1 id="exit_status">
229
325
<title>EXIT STATUS</title>
327
This program will exit with a successful (zero) exit status if a
328
server could be found and the password received from it could be
329
successfully decrypted and output on standard output. The
330
program will exit with a non-zero exit status only if a critical
331
error occurs. Otherwise, it will forever connect to new
332
<application>Mandos</application> servers as they appear, trying
333
to get a decryptable password and print it.
234
337
<refsect1 id="environment">
235
338
<title>ENVIRONMENT</title>
340
This program does not use any environment variables, not even
341
the ones provided by <citerefentry><refentrytitle
342
>cryptsetup</refentrytitle><manvolnum>8</manvolnum>
240
347
<refsect1 id="file">
241
348
<title>FILES</title>
351
<term><filename>/conf/conf.d/mandos/pubkey.txt</filename
353
<term><filename>/conf/conf.d/mandos/seckey.txt</filename
357
OpenPGP public and private key files, in <quote>ASCII
358
Armor</quote> format. These are the default file names,
359
they can be changed with the <option>--pubkey</option> and
360
<option>--seckey</option> options.
367
<!-- <refsect1 id="bugs"> -->
368
<!-- <title>BUGS</title> -->
252
373
<refsect1 id="example">
253
374
<title>EXAMPLE</title>
376
Note that normally, command line options will not be given
377
directly, but via options for the Mandos <citerefentry
378
><refentrytitle>plugin-runner</refentrytitle>
379
<manvolnum>8mandos</manvolnum></citerefentry>.
383
Normal invocation needs no options, if the network interface
384
is <quote>eth0</quote>:
387
<userinput>&COMMANDNAME;</userinput>
392
Search for Mandos servers (and connect to them) using another
396
<!-- do not wrap this line -->
397
<userinput>&COMMANDNAME; --interface eth1</userinput>
402
Run in debug mode, and use a custom key:
406
<!-- do not wrap this line -->
407
<userinput>&COMMANDNAME; --debug --pubkey keydir/pubkey.txt --seckey keydir/seckey.txt</userinput>
413
Run in debug mode, with a custom key, and do not use Zeroconf
414
to locate a server; connect directly to the IPv6 address
415
<quote><systemitem class="ipaddress"
416
>2001:db8:f983:bd0b:30de:ae4a:71f2:f672</systemitem></quote>,
417
port 4711, using interface eth2:
421
<!-- do not wrap this line -->
422
<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
428
<refsect1 id="security">
259
429
<title>SECURITY</title>
431
This program is set-uid to root, but will switch back to the
432
original (and presumably non-privileged) user and group after
433
bringing up the network interface.
436
To use this program for its intended purpose (see <xref
437
linkend="purpose"/>), the password for the root file system will
438
have to be given out to be stored in a server computer, after
439
having been encrypted using an OpenPGP key. This encrypted data
440
which will be stored in a server can only be decrypted by the
441
OpenPGP key, and the data will only be given out to those
442
clients who can prove they actually have that key. This key,
443
however, is stored unencrypted on the client side in its initial
444
<acronym>RAM</acronym> disk image file system. This is normally
445
readable by all, but this is normally fixed during installation
446
of this program; file permissions are set so that no-one is able
450
The only remaining weak point is that someone with physical
451
access to the client hard drive might turn off the client
452
computer, read the OpenPGP keys directly from the hard drive,
453
and communicate with the server. To safeguard against this, the
454
server is supposed to notice the client disappearing and stop
455
giving out the encrypted data. Therefore, it is important to
456
set the timeout and checker interval values tightly on the
457
server. See <citerefentry><refentrytitle
458
>mandos</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
461
It will also help if the checker program on the server is
462
configured to request something from the client which can not be
463
spoofed by someone else on the network, unlike unencrypted
464
<acronym>ICMP</acronym> echo (<quote>ping</quote>) replies.
467
<emphasis>Note</emphasis>: This makes it completely insecure to
468
have <application >Mandos</application> clients which dual-boot
469
to another operating system which is <emphasis>not</emphasis>
470
trusted to keep the initial <acronym>RAM</acronym> disk image
264
475
<refsect1 id="see_also">
265
476
<title>SEE ALSO</title>
478
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
479
<manvolnum>8</manvolnum></citerefentry>,
480
<citerefentry><refentrytitle>crypttab</refentrytitle>
481
<manvolnum>5</manvolnum></citerefentry>,
267
482
<citerefentry><refentrytitle>mandos</refentrytitle>
268
483
<manvolnum>8</manvolnum></citerefentry>,
269
484
<citerefentry><refentrytitle>password-prompt</refentrytitle>