140
151
</refsynopsisdiv>
142
153
<refsect1 id="description">
143
154
<title>DESCRIPTION</title>
145
<command>&COMMANDNAME;</command> is a program which is meant to
146
be specified as a <quote>keyscript</quote> for the root disk in
156
<command>&COMMANDNAME;</command> is a plugin runner that waits
157
for any of its plugins to return sucessfull with a password, and
158
passes it to cryptsetup as stdout message. This command is not
159
meant to be invoked directly, but is instead meant to be run by
160
cryptsetup by being specified in /etc/crypttab as a keyscript
161
and subsequlently started in the initrd environment. See
147
162
<citerefentry><refentrytitle>crypttab</refentrytitle>
148
<manvolnum>5</manvolnum></citerefentry>. The aim of this
149
program is therefore to output a password, which then
150
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
151
<manvolnum>8</manvolnum></citerefentry> will use to unlock the
155
This program is not meant to be invoked directly, but can be in
156
order to test it. Note that any password obtained will simply
157
be output on standard output.
161
<refsect1 id="purpose">
162
<title>PURPOSE</title>
164
The purpose of this is to enable <emphasis>remote and unattended
165
rebooting</emphasis> of client host computer with an
166
<emphasis>encrypted root file system</emphasis>. See <xref
167
linkend="overview"/> for details.
163
<manvolnum>5</manvolnum></citerefentry> for more information on
168
plugins is looked for in the plugins directory which by default will be
169
/conf/conf.d/mandos/plugins.d if not changed by option --plugin-dir.
172
173
<title>OPTIONS</title>
175
<term><option>--global-env
176
<replaceable>ENV</replaceable><literal>=</literal><replaceable
177
>value</replaceable></option></term>
179
<replaceable>ENV</replaceable><literal>=</literal><replaceable
180
>value</replaceable></option></term>
183
This option will add an environment variable setting to
184
all plugins. This will override any inherited environment
191
<term><option>--env-for
192
<replaceable>PLUGIN</replaceable><literal>:</literal
193
><replaceable>ENV</replaceable><literal>=</literal
194
><replaceable>value</replaceable></option></term>
196
<replaceable>PLUGIN</replaceable><literal>:</literal
197
><replaceable>ENV</replaceable><literal>=</literal
198
><replaceable>value</replaceable></option></term>
201
This option will add an environment variable setting to
202
the <replaceable>PLUGIN</replaceable> plugin. This will
203
override any inherited environment variables or
204
environment variables specified using
205
<option>--global-env</option>.
211
176
<term><option>--global-options
212
177
<replaceable>OPTIONS</replaceable></option></term>
214
179
<replaceable>OPTIONS</replaceable></option></term>
217
Pass some options to <emphasis>all</emphasis> plugins.
218
<replaceable>OPTIONS</replaceable> is a comma separated
219
list of options. This is not a very useful option, except
220
for specifying the <quote><option>--debug</option></quote>
221
option to all plugins.
182
Global options given to all plugins as additional start
183
arguments. Options are specified with a -o flag followed
184
by a comma separated string of options.
227
190
<term><option>--options-for
228
191
<replaceable>PLUGIN</replaceable><literal>:</literal
232
195
><replaceable>OPTION</replaceable></option></term>
235
Pass some options to a specific plugin. <replaceable
236
>PLUGIN</replaceable> is the name (file basename) of a
237
plugin, and <replaceable>OPTIONS</replaceable> is a comma
238
separated list of options.
241
Note that since options are not split on whitespace, the
242
way to pass, to the plugin
243
<quote><filename>foo</filename></quote>, the option
244
<option>--bar</option> with the option argument
245
<quote>baz</quote> is either
246
<userinput>--options-for=foo:--bar=baz</userinput> or
247
<userinput>--options-for=foo:--bar,baz</userinput>. Using
248
<userinput>--options-for="foo:--bar baz"</userinput>. will
249
<emphasis>not</emphasis> work.
198
Plugin specific options given to the plugin as additional
199
start arguments. Options are specified with a -o flag
200
followed by a comma separated string of options.
255
<term><option>--disable
206
<term><option> --disable
256
207
<replaceable>PLUGIN</replaceable></option></term>
258
209
<replaceable>PLUGIN</replaceable></option></term>
261
Disable the plugin named
262
<replaceable>PLUGIN</replaceable>. The plugin will not be
212
Disable a specific plugin
269
<term><option>--enable
270
<replaceable>PLUGIN</replaceable></option></term>
272
<replaceable>PLUGIN</replaceable></option></term>
275
Re-enable the plugin named
276
<replaceable>PLUGIN</replaceable>. This is only useful to
277
undo a previous <option>--disable</option> option, maybe
278
from the configuration file.
284
218
<term><option>--groupid
285
219
<replaceable>ID</replaceable></option></term>
288
Change to group ID <replaceable>ID</replaceable> on
289
startup. The default is 65534. All plugins will be
290
started using this group ID. <emphasis>Note:</emphasis>
291
This must be a number, not a name.
222
Group ID the plugins will run as
297
228
<term><option>--userid
298
229
<replaceable>ID</replaceable></option></term>
301
Change to user ID <replaceable>ID</replaceable> on
302
startup. The default is 65534. All plugins will be
303
started using this user ID. <emphasis>Note:</emphasis>
304
This must be a number, not a name.
232
User ID the plugins will run as
310
238
<term><option>--plugin-dir
311
239
<replaceable>DIRECTORY</replaceable></option></term>
314
Specify a different plugin directory. The default is
315
<filename>/lib/mandos/plugins.d</filename>, which will
316
exist in the initial <acronym>RAM</acronym> disk
323
<term><option>--config-file
324
<replaceable>FILE</replaceable></option></term>
327
Specify a different file to read additional options from.
328
See <xref linkend="files"/>. Other command line options
329
will override options specified in the file.
242
Specify a different plugin directory
364
267
<term><option>--usage</option></term>
367
Gives a short usage message.
270
Gives a short usage message
373
276
<term><option>--version</option></term>
374
277
<term><option>-V</option></term>
377
Prints the program version.
280
Prints the program version
384
<refsect1 id="overview">
385
<title>OVERVIEW</title>
386
<xi:include href="overview.xml"/>
388
This program will run on the client side in the initial
389
<acronym>RAM</acronym> disk environment, and is responsible for
390
getting a password. It does this by running plugins, one of
391
which will normally be the actual client program communicating
395
<refsect1 id="plugins">
396
<title>PLUGINS</title>
398
This program will get a password by running a number of
399
<firstterm>plugins</firstterm>, which are simply executable
400
programs in a directory in the initial <acronym>RAM</acronym>
401
disk environment. The default directory is
402
<filename>/lib/mandos/plugins.d</filename>, but this can be
403
changed with the <option>--plugin-dir</option> option. The
404
plugins are started in parallel, and the first plugin to output
405
a password <emphasis>and</emphasis> exit with a successful exit
406
code will make this plugin-runner output the password from that
407
plugin, stop any other plugins, and exit.
410
<refsect2 id="writing_plugins">
411
<title>WRITING PLUGINS</title>
413
A plugin is simply a program which prints a password to its
414
standard output and then exits with a successful (zero) exit
415
status. If the exit status is not zero, any output on
416
standard output will be ignored by the plugin runner. Any
417
output on its standard error channel will simply be passed to
418
the standard error of the plugin runner, usually the system
422
If the password is a single-line, manually entered passprase,
423
a final trailing newline character should
424
<emphasis>not</emphasis> be printed.
427
The plugin will run in the initial RAM disk environment, so
428
care must be taken not to depend on any files or running
429
services not available there.
432
The plugin must exit cleanly and free all allocated resources
433
upon getting the TERM signal, since this is what the plugin
434
runner uses to stop all other plugins when one plugin has
435
output a password and exited cleanly.
438
The plugin must not use resources, like for instance reading
439
from the standard input, without knowing that no other plugin
443
It is useful, but not required, for the plugin to take the
444
<option>--debug</option> option.
449
<refsect1 id="fallback">
450
<title>FALLBACK</title>
452
If no plugins succeed, this program will, as a fallback, ask for
453
a password on the console using <citerefentry><refentrytitle
454
>getpass</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
455
and output it. This is not meant to be the normal mode of
456
operation, as there is a separate plugin for getting a password
461
287
<refsect1 id="exit_status">
462
288
<title>EXIT STATUS</title>
464
Exit status of this program is zero if no errors were
465
encountered, and otherwise not. The fallback (see <xref
466
linkend="fallback"/>) may or may not have succeeded in either
471
<refsect1 id="environment">
472
<title>ENVIRONMENT</title>
474
This program does not use any environment variables itself, it
475
only passes on its environment to all the plugins. The
476
environment passed to plugins can be modified using the
477
<option>--global-env</option> and <option>--env-for</option>
482
<refsect1 id="files">
483
294
<title>FILES</title>
488
>/conf/conf.d/mandos/plugin-runner.conf</filename></term>
491
Since this program will be run as a keyscript, there is
492
little to no opportunity to pass command line arguments
493
to it. Therefore, it will <emphasis>also</emphasis>
494
read this file and use its contents as
495
whitespace-separated command line options. Also,
496
everything from a <quote>#</quote> character to the end
497
of a line is ignored.
500
This program is meant to run in the initial RAM disk
501
environment, so that is where this file is assumed to
502
exist. The file does not need to exist in the normal
506
This file will be processed <emphasis>before</emphasis>
507
the normal command line options, so the latter can
508
override the former, if need be.
511
This file name is the default; the file to read for
512
arguments can be changed using the
513
<option>--config-file</option> option.
299
<refsect1 id="notes">
521
305
<refsect1 id="bugs">
522
306
<title>BUGS</title>
524
The <option>--config-file</option> option is ignored when
525
specified from within a configuration file.
529
311
<refsect1 id="examples">
530
312
<title>EXAMPLE</title>
533
Normal invocation needs no options:
536
<userinput>&COMMANDNAME;</userinput>
541
Run the program, but not the plugins, in debug mode:
545
<!-- do not wrap this line -->
546
<userinput>&COMMANDNAME; --debug</userinput>
552
Run all plugins, but run the <quote>foo</quote> plugin in
557
<!-- do not wrap this line -->
558
<userinput>&COMMANDNAME; --options-for=foo:--debug</userinput>
564
Run all plugins, but not the program, in debug mode:
568
<!-- do not wrap this line -->
569
<userinput>&COMMANDNAME; --global-options=--debug</userinput>
575
Run plugins from a different directory, read a different
576
configuration file, and add two options to the
577
<citerefentry><refentrytitle >mandos-client</refentrytitle>
578
<manvolnum>8mandos</manvolnum></citerefentry> plugin:
582
<!-- do not wrap this line -->
583
<userinput>cd /etc/keys/mandos; &COMMANDNAME; --config-file=/etc/mandos/plugin-runner.conf --plugin-dir /usr/lib/mandos/plugins.d --options-for=mandos-client:--pubkey=pubkey.txt,--seckey=seckey.txt</userinput>
588
317
<refsect1 id="security">
589
318
<title>SECURITY</title>
591
This program will, when starting, try to switch to another user.
592
If it is started as root, it will succeed, and will by default
593
switch to user and group 65534, which are assumed to be
594
non-privileged. This user and group is then what all plugins
595
will be started as. Therefore, the only way to run a plugin as
596
a privileged user is to have the set-user-ID or set-group-ID bit
597
set on the plugin executable file (see <citerefentry>
598
<refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum>
602
If this program is used as a keyscript in <citerefentry
603
><refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum>
604
</citerefentry>, there is a slight risk that if this program
605
fails to work, there might be no way to boot the system except
606
for booting from another media and editing the initial RAM disk
607
image to not run this program. This is, however, unlikely,
608
since the <citerefentry><refentrytitle
609
>password-prompt</refentrytitle><manvolnum>8mandos</manvolnum>
610
</citerefentry> plugin will read a password from the console in
611
case of failure of the other plugins, and this plugin runner
612
will also, in case of catastrophic failure, itself fall back to
613
asking and outputting a password on the console (see <xref
614
linkend="fallback"/>).
618
323
<refsect1 id="see_also">
619
324
<title>SEE ALSO</title>
621
<citerefentry><refentrytitle>intro</refentrytitle>
622
<manvolnum>8mandos</manvolnum></citerefentry>,
623
326
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
624
327
<manvolnum>8</manvolnum></citerefentry>,
625
<citerefentry><refentrytitle>crypttab</refentrytitle>
626
<manvolnum>5</manvolnum></citerefentry>,
627
<citerefentry><refentrytitle>execve</refentrytitle>
628
<manvolnum>2</manvolnum></citerefentry>,
629
328
<citerefentry><refentrytitle>mandos</refentrytitle>
630
329
<manvolnum>8</manvolnum></citerefentry>,
631
330
<citerefentry><refentrytitle>password-prompt</refentrytitle>
632
331
<manvolnum>8mandos</manvolnum></citerefentry>,
633
<citerefentry><refentrytitle>mandos-client</refentrytitle>
332
<citerefentry><refentrytitle>password-request</refentrytitle>
634
333
<manvolnum>8mandos</manvolnum></citerefentry>
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