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<filename>/lib/mandos/plugins.d</filename>, but this can be
429
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changed with the <option>--plugin-dir</option> option. The
430
328
plugins are started in parallel, and the first plugin to output
431
a password <emphasis>and</emphasis> exit with a successful exit
432
code will make this plugin-runner output the password from that
433
plugin, stop any other plugins, and exit.
329
a password and exit with a successful exit code will make this
330
plugin-runner output that password, stop any other plugins, and
436
<refsect2 id="writing_plugins">
437
<title>WRITING PLUGINS</title>
439
A plugin is simply a program which prints a password to its
440
standard output and then exits with a successful (zero) exit
441
status. If the exit status is not zero, any output on
442
standard output will be ignored by the plugin runner. Any
443
output on its standard error channel will simply be passed to
444
the standard error of the plugin runner, usually the system
448
If the password is a single-line, manually entered passprase,
449
a final trailing newline character should
450
<emphasis>not</emphasis> be printed.
453
The plugin will run in the initial RAM disk environment, so
454
care must be taken not to depend on any files or running
455
services not available there. Any helper executables required
456
by the plugin (which are not in the <envar>PATH</envar>) can
457
be placed in the plugin helper directory, the name of which
458
will be made available to the plugin via the
459
<envar>MANDOSPLUGINHELPERDIR</envar> environment variable.
462
The plugin must exit cleanly and free all allocated resources
463
upon getting the TERM signal, since this is what the plugin
464
runner uses to stop all other plugins when one plugin has
465
output a password and exited cleanly.
468
The plugin must not use resources, like for instance reading
469
from the standard input, without knowing that no other plugin
473
It is useful, but not required, for the plugin to take the
474
<option>--debug</option> option.
479
<refsect1 id="fallback">
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336
<title>FALLBACK</title>
482
If no plugins succeed, this program will, as a fallback, ask for
483
a password on the console using <citerefentry><refentrytitle
484
>getpass</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
485
and output it. This is not meant to be the normal mode of
486
operation, as there is a separate plugin for getting a password
491
340
<refsect1 id="exit_status">
492
341
<title>EXIT STATUS</title>
494
Exit status of this program is zero if no errors were
495
encountered, and otherwise not. The fallback (see <xref
496
linkend="fallback"/>) may or may not have succeeded in either
501
<refsect1 id="environment">
502
<title>ENVIRONMENT</title>
504
This program does not use any environment variables itself, it
505
only passes on its environment to all the plugins. The
506
environment passed to plugins can be modified using the
507
<option>--global-env</option> and <option>--env-for</option>
508
options. Also, the <option>--plugin-helper-dir</option> option
509
will affect the environment variable
510
<envar>MANDOSPLUGINHELPERDIR</envar> for the plugins.
514
<refsect1 id="files">
515
347
<title>FILES</title>
520
>/conf/conf.d/mandos/plugin-runner.conf</filename></term>
523
Since this program will be run as a keyscript, there is
524
little to no opportunity to pass command line arguments
525
to it. Therefore, it will <emphasis>also</emphasis>
526
read this file and use its contents as
527
whitespace-separated command line options. Also,
528
everything from a <quote>#</quote> character to the end
529
of a line is ignored.
532
This program is meant to run in the initial RAM disk
533
environment, so that is where this file is assumed to
534
exist. The file does not need to exist in the normal
538
This file will be processed <emphasis>before</emphasis>
539
the normal command line options, so the latter can
540
override the former, if need be.
543
This file name is the default; the file to read for
544
arguments can be changed using the
545
<option>--config-file</option> option.
550
<term><filename class="directory"
551
>/lib/mandos/plugins.d</filename></term>
554
The default plugin directory; can be changed by the
555
<option>--plugin-dir</option> option.
560
<term><filename class="directory"
561
>/lib/mandos/plugin-helpers</filename></term>
564
The default plugin helper directory; can be changed by
565
the <option>--plugin-helper-dir</option> option.
352
<refsect1 id="notes">
573
358
<refsect1 id="bugs">
574
359
<title>BUGS</title>
576
The <option>--config-file</option> option is ignored when
577
specified from within a configuration file.
579
<xi:include href="bugs.xml"/>
582
364
<refsect1 id="examples">
583
365
<title>EXAMPLE</title>
586
Normal invocation needs no options:
589
<userinput>&COMMANDNAME;</userinput>
594
Run the program, but not the plugins, in debug mode:
598
<!-- do not wrap this line -->
599
<userinput>&COMMANDNAME; --debug</userinput>
605
Run all plugins, but run the <quote>foo</quote> plugin in
610
<!-- do not wrap this line -->
611
<userinput>&COMMANDNAME; --options-for=foo:--debug</userinput>
617
Run all plugins, but not the program, in debug mode:
621
<!-- do not wrap this line -->
622
<userinput>&COMMANDNAME; --global-options=--debug</userinput>
628
Read a different configuration file, run plugins from a
629
different directory, specify an alternate plugin helper
630
directory and add two options to the
631
<citerefentry><refentrytitle >mandos-client</refentrytitle>
632
<manvolnum>8mandos</manvolnum></citerefentry> plugin:
636
<!-- do not wrap this line -->
637
<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>
642
370
<refsect1 id="security">
643
371
<title>SECURITY</title>
645
This program will, when starting, try to switch to another user.
646
If it is started as root, it will succeed, and will by default
647
switch to user and group 65534, which are assumed to be
648
non-privileged. This user and group is then what all plugins
649
will be started as. Therefore, the only way to run a plugin as
650
a privileged user is to have the set-user-ID or set-group-ID bit
651
set on the plugin executable file (see <citerefentry>
652
<refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum>
656
If this program is used as a keyscript in <citerefentry
657
><refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum>
658
</citerefentry>, there is a slight risk that if this program
659
fails to work, there might be no way to boot the system except
660
for booting from another media and editing the initial RAM disk
661
image to not run this program. This is, however, unlikely,
662
since the <citerefentry><refentrytitle
663
>password-prompt</refentrytitle><manvolnum>8mandos</manvolnum>
664
</citerefentry> plugin will read a password from the console in
665
case of failure of the other plugins, and this plugin runner
666
will also, in case of catastrophic failure, itself fall back to
667
asking and outputting a password on the console (see <xref
668
linkend="fallback"/>).
672
376
<refsect1 id="see_also">
673
377
<title>SEE ALSO</title>
675
<citerefentry><refentrytitle>intro</refentrytitle>
676
<manvolnum>8mandos</manvolnum></citerefentry>,
677
379
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
678
380
<manvolnum>8</manvolnum></citerefentry>,
679
<citerefentry><refentrytitle>crypttab</refentrytitle>
680
<manvolnum>5</manvolnum></citerefentry>,
681
<citerefentry><refentrytitle>execve</refentrytitle>
682
<manvolnum>2</manvolnum></citerefentry>,
683
381
<citerefentry><refentrytitle>mandos</refentrytitle>
684
382
<manvolnum>8</manvolnum></citerefentry>,
685
383
<citerefentry><refentrytitle>password-prompt</refentrytitle>
686
384
<manvolnum>8mandos</manvolnum></citerefentry>,
687
<citerefentry><refentrytitle>mandos-client</refentrytitle>
385
<citerefentry><refentrytitle>password-request</refentrytitle>
688
386
<manvolnum>8mandos</manvolnum></citerefentry>
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