148
127
</refsynopsisdiv>
150
129
<refsect1 id="description">
151
130
<title>DESCRIPTION</title>
153
<command>&COMMANDNAME;</command> is a program which is meant to
154
be specified as a <quote>keyscript</quote> for the root disk in
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
155
138
<citerefentry><refentrytitle>crypttab</refentrytitle>
156
<manvolnum>5</manvolnum></citerefentry>. The aim of this
157
program is therefore to output a password, which then
158
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
159
<manvolnum>8</manvolnum></citerefentry> will use to unlock the
163
This program is not meant to be invoked directly, but can be in
164
order to test it. Note that any password obtained will simply
165
be output on standard output.
169
<refsect1 id="purpose">
170
<title>PURPOSE</title>
172
The purpose of this is to enable <emphasis>remote and unattended
173
rebooting</emphasis> of client host computer with an
174
<emphasis>encrypted root file system</emphasis>. See <xref
175
linkend="overview"/> for details.
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.
180
149
<title>OPTIONS</title>
183
<term><option>--global-env
184
<replaceable>ENV</replaceable><literal>=</literal><replaceable
185
>value</replaceable></option></term>
187
<replaceable>ENV</replaceable><literal>=</literal><replaceable
188
>value</replaceable></option></term>
191
This option will add an environment variable setting to
192
all plugins. This will override any inherited environment
199
<term><option>--env-for
200
<replaceable>PLUGIN</replaceable><literal>:</literal
201
><replaceable>ENV</replaceable><literal>=</literal
202
><replaceable>value</replaceable></option></term>
204
<replaceable>PLUGIN</replaceable><literal>:</literal
205
><replaceable>ENV</replaceable><literal>=</literal
206
><replaceable>value</replaceable></option></term>
209
This option will add an environment variable setting to
210
the <replaceable>PLUGIN</replaceable> plugin. This will
211
override any inherited environment variables or
212
environment variables specified using
213
<option>--global-env</option>.
219
152
<term><option>--global-options
220
153
<replaceable>OPTIONS</replaceable></option></term>
222
155
<replaceable>OPTIONS</replaceable></option></term>
225
Pass some options to <emphasis>all</emphasis> plugins.
226
<replaceable>OPTIONS</replaceable> is a comma separated
227
list of options. This is not a very useful option, except
228
for specifying the <quote><option>--debug</option></quote>
229
option to all plugins.
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.
235
166
<term><option>--options-for
236
167
<replaceable>PLUGIN</replaceable><literal>:</literal
240
171
><replaceable>OPTION</replaceable></option></term>
243
Pass some options to a specific plugin. <replaceable
244
>PLUGIN</replaceable> is the name (file basename) of a
245
plugin, and <replaceable>OPTIONS</replaceable> is a comma
246
separated list of options.
249
Note that since options are not split on whitespace, the
250
way to pass, to the plugin
251
<quote><filename>foo</filename></quote>, the option
252
<option>--bar</option> with the option argument
253
<quote>baz</quote> is either
254
<userinput>--options-for=foo:--bar=baz</userinput> or
255
<userinput>--options-for=foo:--bar,baz</userinput>. Using
256
<userinput>--options-for="foo:--bar baz"</userinput>. will
257
<emphasis>not</emphasis> work.
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.
263
<term><option>--disable
182
<term><option> --disable
264
183
<replaceable>PLUGIN</replaceable></option></term>
266
185
<replaceable>PLUGIN</replaceable></option></term>
269
Disable the plugin named
270
<replaceable>PLUGIN</replaceable>. The plugin will not be
277
<term><option>--enable
278
<replaceable>PLUGIN</replaceable></option></term>
280
<replaceable>PLUGIN</replaceable></option></term>
283
Re-enable the plugin named
284
<replaceable>PLUGIN</replaceable>. This is only useful to
285
undo a previous <option>--disable</option> option, maybe
286
from the configuration file.
188
Disable a specific plugin
292
194
<term><option>--groupid
293
195
<replaceable>ID</replaceable></option></term>
296
Change to group ID <replaceable>ID</replaceable> on
297
startup. The default is 65534. All plugins will be
298
started using this group ID. <emphasis>Note:</emphasis>
299
This must be a number, not a name.
198
Group ID the plugins will run as
305
204
<term><option>--userid
306
205
<replaceable>ID</replaceable></option></term>
309
Change to user ID <replaceable>ID</replaceable> on
310
startup. The default is 65534. All plugins will be
311
started using this user ID. <emphasis>Note:</emphasis>
312
This must be a number, not a name.
208
User ID the plugins will run as
318
214
<term><option>--plugin-dir
319
215
<replaceable>DIRECTORY</replaceable></option></term>
322
Specify a different plugin directory. The default is
323
<filename>/lib/mandos/plugins.d</filename>, which will
324
exist in the initial <acronym>RAM</acronym> disk
331
<term><option>--plugin-helper-dir
332
<replaceable>DIRECTORY</replaceable></option></term>
335
Specify a different plugin helper directory. The default
336
is <filename>/lib/mandos/plugin-helpers</filename>, which
337
will exist in the initial <acronym>RAM</acronym> disk
338
environment. (This will simply be passed to all plugins
339
via the <envar>MANDOSPLUGINHELPERDIR</envar> environment
340
variable. See <xref linkend="writing_plugins"/>)
346
<term><option>--config-file
347
<replaceable>FILE</replaceable></option></term>
350
Specify a different file to read additional options from.
351
See <xref linkend="files"/>. Other command line options
352
will override options specified in the file.
218
Specify a different plugin directory
387
243
<term><option>--usage</option></term>
390
Gives a short usage message.
246
Gives a short usage message
396
252
<term><option>--version</option></term>
397
253
<term><option>-V</option></term>
400
Prints the program version.
256
Prints the program version
407
<refsect1 id="overview">
408
<title>OVERVIEW</title>
409
<xi:include href="overview.xml"/>
411
This program will run on the client side in the initial
412
<acronym>RAM</acronym> disk environment, and is responsible for
413
getting a password. It does this by running plugins, one of
414
which will normally be the actual client program communicating
418
<refsect1 id="plugins">
419
<title>PLUGINS</title>
421
This program will get a password by running a number of
422
<firstterm>plugins</firstterm>, which are simply executable
423
programs in a directory in the initial <acronym>RAM</acronym>
424
disk environment. The default directory is
425
<filename>/lib/mandos/plugins.d</filename>, but this can be
426
changed with the <option>--plugin-dir</option> option. The
427
plugins are started in parallel, and the first plugin to output
428
a password <emphasis>and</emphasis> exit with a successful exit
429
code will make this plugin-runner output the password from that
430
plugin, stop any other plugins, and exit.
433
<refsect2 id="writing_plugins">
434
<title>WRITING PLUGINS</title>
436
A plugin is simply a program which prints a password to its
437
standard output and then exits with a successful (zero) exit
438
status. If the exit status is not zero, any output on
439
standard output will be ignored by the plugin runner. Any
440
output on its standard error channel will simply be passed to
441
the standard error of the plugin runner, usually the system
445
If the password is a single-line, manually entered passprase,
446
a final trailing newline character should
447
<emphasis>not</emphasis> be printed.
450
The plugin will run in the initial RAM disk environment, so
451
care must be taken not to depend on any files or running
452
services not available there. Any helper executables required
453
by the plugin (which are not in the <envar>PATH</envar>) can
454
be placed in the plugin helper directory, the name of which
455
will be made available to the plugin via the
456
<envar>MANDOSPLUGINHELPERDIR</envar> environment variable.
459
The plugin must exit cleanly and free all allocated resources
460
upon getting the TERM signal, since this is what the plugin
461
runner uses to stop all other plugins when one plugin has
462
output a password and exited cleanly.
465
The plugin must not use resources, like for instance reading
466
from the standard input, without knowing that no other plugin
470
It is useful, but not required, for the plugin to take the
471
<option>--debug</option> option.
476
<refsect1 id="fallback">
477
<title>FALLBACK</title>
479
If no plugins succeed, this program will, as a fallback, ask for
480
a password on the console using <citerefentry><refentrytitle
481
>getpass</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
482
and output it. This is not meant to be the normal mode of
483
operation, as there is a separate plugin for getting a password
488
263
<refsect1 id="exit_status">
489
264
<title>EXIT STATUS</title>
491
Exit status of this program is zero if no errors were
492
encountered, and otherwise not. The fallback (see <xref
493
linkend="fallback"/>) may or may not have succeeded in either
498
<refsect1 id="environment">
499
<title>ENVIRONMENT</title>
501
This program does not use any environment variables itself, it
502
only passes on its environment to all the plugins. The
503
environment passed to plugins can be modified using the
504
<option>--global-env</option> and <option>--env-for</option>
505
options. Also, the <option>--plugin-helper-dir</option> option
506
will affect the environment variable
507
<envar>MANDOSPLUGINHELPERDIR</envar> for the plugins.
511
<refsect1 id="files">
512
270
<title>FILES</title>
517
>/conf/conf.d/mandos/plugin-runner.conf</filename></term>
520
Since this program will be run as a keyscript, there is
521
little to no opportunity to pass command line arguments
522
to it. Therefore, it will <emphasis>also</emphasis>
523
read this file and use its contents as
524
whitespace-separated command line options. Also,
525
everything from a <quote>#</quote> character to the end
526
of a line is ignored.
529
This program is meant to run in the initial RAM disk
530
environment, so that is where this file is assumed to
531
exist. The file does not need to exist in the normal
535
This file will be processed <emphasis>before</emphasis>
536
the normal command line options, so the latter can
537
override the former, if need be.
540
This file name is the default; the file to read for
541
arguments can be changed using the
542
<option>--config-file</option> option.
275
<refsect1 id="notes">
550
281
<refsect1 id="bugs">
551
282
<title>BUGS</title>
553
The <option>--config-file</option> option is ignored when
554
specified from within a configuration file.
558
287
<refsect1 id="examples">
559
288
<title>EXAMPLE</title>
562
Normal invocation needs no options:
565
<userinput>&COMMANDNAME;</userinput>
570
Run the program, but not the plugins, in debug mode:
574
<!-- do not wrap this line -->
575
<userinput>&COMMANDNAME; --debug</userinput>
581
Run all plugins, but run the <quote>foo</quote> plugin in
586
<!-- do not wrap this line -->
587
<userinput>&COMMANDNAME; --options-for=foo:--debug</userinput>
593
Run all plugins, but not the program, in debug mode:
597
<!-- do not wrap this line -->
598
<userinput>&COMMANDNAME; --global-options=--debug</userinput>
604
Read a different configuration file, run plugins from a
605
different directory, specify an alternate plugin helper
606
directory and add two options to the
607
<citerefentry><refentrytitle >mandos-client</refentrytitle>
608
<manvolnum>8mandos</manvolnum></citerefentry> plugin:
612
<!-- do not wrap this line -->
613
<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>
618
293
<refsect1 id="security">
619
294
<title>SECURITY</title>
621
This program will, when starting, try to switch to another user.
622
If it is started as root, it will succeed, and will by default
623
switch to user and group 65534, which are assumed to be
624
non-privileged. This user and group is then what all plugins
625
will be started as. Therefore, the only way to run a plugin as
626
a privileged user is to have the set-user-ID or set-group-ID bit
627
set on the plugin executable file (see <citerefentry>
628
<refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum>
632
If this program is used as a keyscript in <citerefentry
633
><refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum>
634
</citerefentry>, there is a slight risk that if this program
635
fails to work, there might be no way to boot the system except
636
for booting from another media and editing the initial RAM disk
637
image to not run this program. This is, however, unlikely,
638
since the <citerefentry><refentrytitle
639
>password-prompt</refentrytitle><manvolnum>8mandos</manvolnum>
640
</citerefentry> plugin will read a password from the console in
641
case of failure of the other plugins, and this plugin runner
642
will also, in case of catastrophic failure, itself fall back to
643
asking and outputting a password on the console (see <xref
644
linkend="fallback"/>).
648
299
<refsect1 id="see_also">
649
300
<title>SEE ALSO</title>
651
<citerefentry><refentrytitle>intro</refentrytitle>
652
<manvolnum>8mandos</manvolnum></citerefentry>,
653
302
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
654
303
<manvolnum>8</manvolnum></citerefentry>,
655
<citerefentry><refentrytitle>crypttab</refentrytitle>
656
<manvolnum>5</manvolnum></citerefentry>,
657
<citerefentry><refentrytitle>execve</refentrytitle>
658
<manvolnum>2</manvolnum></citerefentry>,
659
304
<citerefentry><refentrytitle>mandos</refentrytitle>
660
305
<manvolnum>8</manvolnum></citerefentry>,
661
306
<citerefentry><refentrytitle>password-prompt</refentrytitle>
662
307
<manvolnum>8mandos</manvolnum></citerefentry>,
663
<citerefentry><refentrytitle>mandos-client</refentrytitle>
308
<citerefentry><refentrytitle>password-request</refentrytitle>
664
309
<manvolnum>8mandos</manvolnum></citerefentry>
669
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