127
149
</refsynopsisdiv>
129
151
<refsect1 id="description">
130
152
<title>DESCRIPTION</title>
132
<command>&COMMANDNAME;</command> is a plugin runner that waits
133
for any of its plugins to return sucessfull with a password, and
134
passes it to cryptsetup as stdout message. This command is not
135
meant to be invoked directly, but is instead meant to be run by
136
cryptsetup by being specified in /etc/crypttab as a keyscript
137
and subsequlently started in the initrd environment. See
154
<command>&COMMANDNAME;</command> is a program which is meant to
155
be specified as a <quote>keyscript</quote> for the root disk in
138
156
<citerefentry><refentrytitle>crypttab</refentrytitle>
139
<manvolnum>5</manvolnum></citerefentry> for more information on
144
plugins is looked for in the plugins directory which by default will be
145
/conf/conf.d/mandos/plugins.d if not changed by option --plugin-dir.
157
<manvolnum>5</manvolnum></citerefentry>. The aim of this
158
program is therefore to output a password, which then
159
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
160
<manvolnum>8</manvolnum></citerefentry> will use to unlock the
164
This program is not meant to be invoked directly, but can be in
165
order to test it. Note that any password obtained will simply
166
be output on standard output.
170
<refsect1 id="purpose">
171
<title>PURPOSE</title>
173
The purpose of this is to enable <emphasis>remote and unattended
174
rebooting</emphasis> of client host computer with an
175
<emphasis>encrypted root file system</emphasis>. See <xref
176
linkend="overview"/> for details.
149
181
<title>OPTIONS</title>
184
<term><option>--global-env
185
<replaceable>ENV</replaceable><literal>=</literal><replaceable
186
>value</replaceable></option></term>
188
<replaceable>ENV</replaceable><literal>=</literal><replaceable
189
>value</replaceable></option></term>
192
This option will add an environment variable setting to
193
all plugins. This will override any inherited environment
200
<term><option>--env-for
201
<replaceable>PLUGIN</replaceable><literal>:</literal
202
><replaceable>ENV</replaceable><literal>=</literal
203
><replaceable>value</replaceable></option></term>
205
<replaceable>PLUGIN</replaceable><literal>:</literal
206
><replaceable>ENV</replaceable><literal>=</literal
207
><replaceable>value</replaceable></option></term>
210
This option will add an environment variable setting to
211
the <replaceable>PLUGIN</replaceable> plugin. This will
212
override any inherited environment variables or
213
environment variables specified using
214
<option>--global-env</option>.
152
220
<term><option>--global-options
153
221
<replaceable>OPTIONS</replaceable></option></term>
155
223
<replaceable>OPTIONS</replaceable></option></term>
158
Global options given to all plugins as additional start
159
arguments. Options are specified with a -o flag followed
160
by a comma separated string of options.
226
Pass some options to <emphasis>all</emphasis> plugins.
227
<replaceable>OPTIONS</replaceable> is a comma separated
228
list of options. This is not a very useful option, except
229
for specifying the <quote><option>--debug</option></quote>
230
option to all plugins.
166
236
<term><option>--options-for
167
237
<replaceable>PLUGIN</replaceable><literal>:</literal
171
241
><replaceable>OPTION</replaceable></option></term>
174
Plugin specific options given to the plugin as additional
175
start arguments. Options are specified with a -o flag
176
followed by a comma separated string of options.
244
Pass some options to a specific plugin. <replaceable
245
>PLUGIN</replaceable> is the name (file basename) of a
246
plugin, and <replaceable>OPTIONS</replaceable> is a comma
247
separated list of options.
250
Note that since options are not split on whitespace, the
251
way to pass, to the plugin
252
<quote><filename>foo</filename></quote>, the option
253
<option>--bar</option> with the option argument
254
<quote>baz</quote> is either
255
<userinput>--options-for=foo:--bar=baz</userinput> or
256
<userinput>--options-for=foo:--bar,baz</userinput>. Using
257
<userinput>--options-for="foo:--bar baz"</userinput>. will
258
<emphasis>not</emphasis> work.
182
<term><option> --disable
264
<term><option>--disable
183
265
<replaceable>PLUGIN</replaceable></option></term>
185
267
<replaceable>PLUGIN</replaceable></option></term>
188
Disable a specific plugin
270
Disable the plugin named
271
<replaceable>PLUGIN</replaceable>. The plugin will not be
278
<term><option>--enable
279
<replaceable>PLUGIN</replaceable></option></term>
281
<replaceable>PLUGIN</replaceable></option></term>
284
Re-enable the plugin named
285
<replaceable>PLUGIN</replaceable>. This is only useful to
286
undo a previous <option>--disable</option> option, maybe
287
from the configuration file.
194
293
<term><option>--groupid
195
294
<replaceable>ID</replaceable></option></term>
198
Group ID the plugins will run as
297
Change to group ID <replaceable>ID</replaceable> on
298
startup. The default is 65534. All plugins will be
299
started using this group ID. <emphasis>Note:</emphasis>
300
This must be a number, not a name.
204
306
<term><option>--userid
205
307
<replaceable>ID</replaceable></option></term>
208
User ID the plugins will run as
310
Change to user ID <replaceable>ID</replaceable> on
311
startup. The default is 65534. All plugins will be
312
started using this user ID. <emphasis>Note:</emphasis>
313
This must be a number, not a name.
214
319
<term><option>--plugin-dir
215
320
<replaceable>DIRECTORY</replaceable></option></term>
218
Specify a different plugin directory
323
Specify a different plugin directory. The default is
324
<filename>/lib/mandos/plugins.d</filename>, which will
325
exist in the initial <acronym>RAM</acronym> disk
332
<term><option>--plugin-helper-dir
333
<replaceable>DIRECTORY</replaceable></option></term>
336
Specify a different plugin helper directory. The default
337
is <filename>/lib/mandos/plugin-helpers</filename>, which
338
will exist in the initial <acronym>RAM</acronym> disk
339
environment. (This will simply be passed to all plugins
340
via the <envar>MANDOSPLUGINHELPERDIR</envar> environment
341
variable. See <xref linkend="writing_plugins"/>)
347
<term><option>--config-file
348
<replaceable>FILE</replaceable></option></term>
351
Specify a different file to read additional options from.
352
See <xref linkend="files"/>. Other command line options
353
will override options specified in the file.
243
388
<term><option>--usage</option></term>
246
Gives a short usage message
391
Gives a short usage message.
252
397
<term><option>--version</option></term>
253
398
<term><option>-V</option></term>
256
Prints the program version
401
Prints the program version.
408
<refsect1 id="overview">
409
<title>OVERVIEW</title>
410
<xi:include href="overview.xml"/>
412
This program will run on the client side in the initial
413
<acronym>RAM</acronym> disk environment, and is responsible for
414
getting a password. It does this by running plugins, one of
415
which will normally be the actual client program communicating
419
<refsect1 id="plugins">
420
<title>PLUGINS</title>
422
This program will get a password by running a number of
423
<firstterm>plugins</firstterm>, which are simply executable
424
programs in a directory in the initial <acronym>RAM</acronym>
425
disk environment. The default directory is
426
<filename>/lib/mandos/plugins.d</filename>, but this can be
427
changed with the <option>--plugin-dir</option> option. The
428
plugins are started in parallel, and the first plugin to output
429
a password <emphasis>and</emphasis> exit with a successful exit
430
code will make this plugin-runner output the password from that
431
plugin, stop any other plugins, and exit.
434
<refsect2 id="writing_plugins">
435
<title>WRITING PLUGINS</title>
437
A plugin is simply a program which prints a password to its
438
standard output and then exits with a successful (zero) exit
439
status. If the exit status is not zero, any output on
440
standard output will be ignored by the plugin runner. Any
441
output on its standard error channel will simply be passed to
442
the standard error of the plugin runner, usually the system
446
If the password is a single-line, manually entered passprase,
447
a final trailing newline character should
448
<emphasis>not</emphasis> be printed.
451
The plugin will run in the initial RAM disk environment, so
452
care must be taken not to depend on any files or running
453
services not available there. Any helper executables required
454
by the plugin (which are not in the <envar>PATH</envar>) can
455
be placed in the plugin helper directory, the name of which
456
will be made available to the plugin via the
457
<envar>MANDOSPLUGINHELPERDIR</envar> environment variable.
460
The plugin must exit cleanly and free all allocated resources
461
upon getting the TERM signal, since this is what the plugin
462
runner uses to stop all other plugins when one plugin has
463
output a password and exited cleanly.
466
The plugin must not use resources, like for instance reading
467
from the standard input, without knowing that no other plugin
471
It is useful, but not required, for the plugin to take the
472
<option>--debug</option> option.
477
<refsect1 id="fallback">
478
<title>FALLBACK</title>
480
If no plugins succeed, this program will, as a fallback, ask for
481
a password on the console using <citerefentry><refentrytitle
482
>getpass</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
483
and output it. This is not meant to be the normal mode of
484
operation, as there is a separate plugin for getting a password
263
489
<refsect1 id="exit_status">
264
490
<title>EXIT STATUS</title>
492
Exit status of this program is zero if no errors were
493
encountered, and otherwise not. The fallback (see <xref
494
linkend="fallback"/>) may or may not have succeeded in either
499
<refsect1 id="environment">
500
<title>ENVIRONMENT</title>
502
This program does not use any environment variables itself, it
503
only passes on its environment to all the plugins. The
504
environment passed to plugins can be modified using the
505
<option>--global-env</option> and <option>--env-for</option>
506
options. Also, the <option>--plugin-helper-dir</option> option
507
will affect the environment variable
508
<envar>MANDOSPLUGINHELPERDIR</envar> for the plugins.
512
<refsect1 id="files">
270
513
<title>FILES</title>
275
<refsect1 id="notes">
518
>/conf/conf.d/mandos/plugin-runner.conf</filename></term>
521
Since this program will be run as a keyscript, there is
522
little to no opportunity to pass command line arguments
523
to it. Therefore, it will <emphasis>also</emphasis>
524
read this file and use its contents as
525
whitespace-separated command line options. Also,
526
everything from a <quote>#</quote> character to the end
527
of a line is ignored.
530
This program is meant to run in the initial RAM disk
531
environment, so that is where this file is assumed to
532
exist. The file does not need to exist in the normal
536
This file will be processed <emphasis>before</emphasis>
537
the normal command line options, so the latter can
538
override the former, if need be.
541
This file name is the default; the file to read for
542
arguments can be changed using the
543
<option>--config-file</option> option.
281
551
<refsect1 id="bugs">
282
552
<title>BUGS</title>
554
The <option>--config-file</option> option is ignored when
555
specified from within a configuration file.
557
<xi:include href="bugs.xml"/>
287
560
<refsect1 id="examples">
288
561
<title>EXAMPLE</title>
564
Normal invocation needs no options:
567
<userinput>&COMMANDNAME;</userinput>
572
Run the program, but not the plugins, in debug mode:
576
<!-- do not wrap this line -->
577
<userinput>&COMMANDNAME; --debug</userinput>
583
Run all plugins, but run the <quote>foo</quote> plugin in
588
<!-- do not wrap this line -->
589
<userinput>&COMMANDNAME; --options-for=foo:--debug</userinput>
595
Run all plugins, but not the program, in debug mode:
599
<!-- do not wrap this line -->
600
<userinput>&COMMANDNAME; --global-options=--debug</userinput>
606
Read a different configuration file, run plugins from a
607
different directory, specify an alternate plugin helper
608
directory and add two options to the
609
<citerefentry><refentrytitle >mandos-client</refentrytitle>
610
<manvolnum>8mandos</manvolnum></citerefentry> plugin:
614
<!-- do not wrap this line -->
615
<userinput>cd /etc/keys/mandos; &COMMANDNAME; --config-file=/etc/mandos/plugin-runner.conf --plugin-dir /usr/lib/x86_64-linux-gnu/mandos/plugins.d --plugin-helper-dir /usr/lib/x86_64-linux-gnu/mandos/plugin-helpers --options-for=mandos-client:--pubkey=pubkey.txt,--seckey=seckey.txt</userinput>
293
620
<refsect1 id="security">
294
621
<title>SECURITY</title>
623
This program will, when starting, try to switch to another user.
624
If it is started as root, it will succeed, and will by default
625
switch to user and group 65534, which are assumed to be
626
non-privileged. This user and group is then what all plugins
627
will be started as. Therefore, the only way to run a plugin as
628
a privileged user is to have the set-user-ID or set-group-ID bit
629
set on the plugin executable file (see <citerefentry>
630
<refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum>
634
If this program is used as a keyscript in <citerefentry
635
><refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum>
636
</citerefentry>, there is a slight risk that if this program
637
fails to work, there might be no way to boot the system except
638
for booting from another media and editing the initial RAM disk
639
image to not run this program. This is, however, unlikely,
640
since the <citerefentry><refentrytitle
641
>password-prompt</refentrytitle><manvolnum>8mandos</manvolnum>
642
</citerefentry> plugin will read a password from the console in
643
case of failure of the other plugins, and this plugin runner
644
will also, in case of catastrophic failure, itself fall back to
645
asking and outputting a password on the console (see <xref
646
linkend="fallback"/>).
299
650
<refsect1 id="see_also">
300
651
<title>SEE ALSO</title>
653
<citerefentry><refentrytitle>intro</refentrytitle>
654
<manvolnum>8mandos</manvolnum></citerefentry>,
302
655
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
303
656
<manvolnum>8</manvolnum></citerefentry>,
657
<citerefentry><refentrytitle>crypttab</refentrytitle>
658
<manvolnum>5</manvolnum></citerefentry>,
659
<citerefentry><refentrytitle>execve</refentrytitle>
660
<manvolnum>2</manvolnum></citerefentry>,
304
661
<citerefentry><refentrytitle>mandos</refentrytitle>
305
662
<manvolnum>8</manvolnum></citerefentry>,
306
663
<citerefentry><refentrytitle>password-prompt</refentrytitle>
307
664
<manvolnum>8mandos</manvolnum></citerefentry>,
308
<citerefentry><refentrytitle>password-request</refentrytitle>
665
<citerefentry><refentrytitle>mandos-client</refentrytitle>
309
666
<manvolnum>8mandos</manvolnum></citerefentry>
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