149
140
</refsynopsisdiv>
151
142
<refsect1 id="description">
152
143
<title>DESCRIPTION</title>
154
<command>&COMMANDNAME;</command> is a plugin runner that waits
155
for any of its plugins to return sucessfull with a password, and
156
passes it to cryptsetup as stdout message. This command is not
157
meant to be invoked directly, but is instead meant to be run by
158
cryptsetup by being specified in /etc/crypttab as a keyscript
159
and subsequlently started in the initrd environment. See
145
<command>&COMMANDNAME;</command> is a program which is meant to
146
be specified as a <quote>keyscript</quote> for the root disk in
160
147
<citerefentry><refentrytitle>crypttab</refentrytitle>
161
<manvolnum>5</manvolnum></citerefentry> for more information on
166
plugins is looked for in the plugins directory which by default will be
167
/conf/conf.d/mandos/plugins.d if not changed by option --plugin-dir.
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.
171
172
<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>.
174
211
<term><option>--global-options
175
212
<replaceable>OPTIONS</replaceable></option></term>
177
214
<replaceable>OPTIONS</replaceable></option></term>
180
Global options given to all plugins as additional start
181
arguments. Options are specified with a -o flag followed
182
by a comma separated string of options.
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.
188
227
<term><option>--options-for
189
228
<replaceable>PLUGIN</replaceable><literal>:</literal
193
232
><replaceable>OPTION</replaceable></option></term>
196
Plugin specific options given to the plugin as additional
197
start arguments. Options are specified with a -o flag
198
followed by a comma separated string of options.
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.
204
<term><option> --disable
255
<term><option>--disable
205
256
<replaceable>PLUGIN</replaceable></option></term>
207
258
<replaceable>PLUGIN</replaceable></option></term>
210
Disable a specific plugin
261
Disable the plugin named
262
<replaceable>PLUGIN</replaceable>. The plugin will not be
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.
216
284
<term><option>--groupid
217
285
<replaceable>ID</replaceable></option></term>
220
Group ID the plugins will run as
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.
226
297
<term><option>--userid
227
298
<replaceable>ID</replaceable></option></term>
230
User ID the plugins will run as
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.
236
310
<term><option>--plugin-dir
237
311
<replaceable>DIRECTORY</replaceable></option></term>
240
Specify a different plugin directory
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.
265
364
<term><option>--usage</option></term>
268
Gives a short usage message
367
Gives a short usage message.
274
373
<term><option>--version</option></term>
275
374
<term><option>-V</option></term>
278
Prints the program version
377
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
285
461
<refsect1 id="exit_status">
286
462
<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">
292
483
<title>FILES</title>
297
<refsect1 id="notes">
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.
303
521
<refsect1 id="bugs">
304
522
<title>BUGS</title>
524
The <option>--config-file</option> option is ignored when
525
specified from within a configuration file.
309
529
<refsect1 id="examples">
310
530
<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>
315
588
<refsect1 id="security">
316
589
<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"/>).
321
618
<refsect1 id="see_also">
322
619
<title>SEE ALSO</title>
621
<citerefentry><refentrytitle>intro</refentrytitle>
622
<manvolnum>8mandos</manvolnum></citerefentry>,
324
623
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
325
624
<manvolnum>8</manvolnum></citerefentry>,
625
<citerefentry><refentrytitle>crypttab</refentrytitle>
626
<manvolnum>5</manvolnum></citerefentry>,
627
<citerefentry><refentrytitle>execve</refentrytitle>
628
<manvolnum>2</manvolnum></citerefentry>,
326
629
<citerefentry><refentrytitle>mandos</refentrytitle>
327
630
<manvolnum>8</manvolnum></citerefentry>,
328
631
<citerefentry><refentrytitle>password-prompt</refentrytitle>
329
632
<manvolnum>8mandos</manvolnum></citerefentry>,
330
<citerefentry><refentrytitle>password-request</refentrytitle>
633
<citerefentry><refentrytitle>mandos-client</refentrytitle>
331
634
<manvolnum>8mandos</manvolnum></citerefentry>
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