137
127
</refsynopsisdiv>
139
129
<refsect1 id="description">
140
130
<title>DESCRIPTION</title>
142
<command>&COMMANDNAME;</command> is a program which is meant to
143
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
144
138
<citerefentry><refentrytitle>crypttab</refentrytitle>
145
<manvolnum>5</manvolnum></citerefentry>. The aim of this
146
program is therefore to output a password, which then
147
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
148
<manvolnum>8</manvolnum></citerefentry> will use to unlock the
152
This program is not meant to be invoked directly, but can be in
153
order to test it. Note that any password obtained will simply
154
be output on standard output.
158
<refsect1 id="purpose">
159
<title>PURPOSE</title>
161
The purpose of this is to enable <emphasis>remote and unattended
162
rebooting</emphasis> of client host computer with an
163
<emphasis>encrypted root file system</emphasis>. See <xref
164
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.
169
149
<title>OPTIONS</title>
172
<term><option>--global-env
173
<replaceable>VAR</replaceable><literal>=</literal><replaceable
174
>value</replaceable></option></term>
176
<replaceable>VAR</replaceable><literal>=</literal><replaceable
177
>value</replaceable></option></term>
180
This option will add an environment variable setting to
181
all plugins. This will override any inherited environment
188
<term><option>--env-for
189
<replaceable>PLUGIN</replaceable><literal>:</literal
190
><replaceable>ENV</replaceable><literal>=</literal
191
><replaceable>value</replaceable></option></term>
193
<replaceable>PLUGIN</replaceable><literal>:</literal
194
><replaceable>ENV</replaceable><literal>=</literal
195
><replaceable>value</replaceable></option></term>
198
This option will add an environment variable setting to
199
the <replaceable>PLUGIN</replaceable> plugin. This will
200
override any inherited environment variables or
201
environment variables specified using
202
<option>--global-env</option>.
208
152
<term><option>--global-options
209
153
<replaceable>OPTIONS</replaceable></option></term>
211
155
<replaceable>OPTIONS</replaceable></option></term>
214
Pass some options to <emphasis>all</emphasis> plugins.
215
<replaceable>OPTIONS</replaceable> is a comma separated
216
list of options. This is not a very useful option, except
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for specifying the <quote><option>--debug</option></quote>
218
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.
224
166
<term><option>--options-for
225
167
<replaceable>PLUGIN</replaceable><literal>:</literal
229
171
><replaceable>OPTION</replaceable></option></term>
232
Pass some options to a specific plugin. <replaceable
233
>PLUGIN</replaceable> is the name (file basename) of a
234
plugin, and <replaceable>OPTIONS</replaceable> is a comma
235
separated list of options.
238
Note that since options are not split on whitespace, the
239
way to pass, to the plugin
240
<quote><filename>foo</filename></quote>, the option
241
<option>--bar</option> with the option argument
242
<quote>baz</quote> is either
243
<userinput>--options-for=foo:--bar=baz</userinput> or
244
<userinput>--options-for=foo:--bar,baz</userinput>. Using
245
<userinput>--options-for="foo:--bar baz"</userinput>. will
246
<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.
252
<term><option>--disable
182
<term><option> --disable
253
183
<replaceable>PLUGIN</replaceable></option></term>
255
185
<replaceable>PLUGIN</replaceable></option></term>
258
Disable the plugin named
259
<replaceable>PLUGIN</replaceable>. The plugin will not be
188
Disable a specific plugin
266
<term><option>--enable
267
<replaceable>PLUGIN</replaceable></option></term>
269
<replaceable>PLUGIN</replaceable></option></term>
272
Re-enable the plugin named
273
<replaceable>PLUGIN</replaceable>. This is only useful to
274
undo a previous <option>--disable</option> option, maybe
275
from the configuration file.
281
194
<term><option>--groupid
282
195
<replaceable>ID</replaceable></option></term>
285
Change to group ID <replaceable>ID</replaceable> on
286
startup. The default is 65534. All plugins will be
287
started using this group ID. <emphasis>Note:</emphasis>
288
This must be a number, not a name.
198
Group ID the plugins will run as
371
253
<term><option>-V</option></term>
374
Prints the program version.
256
Prints the program version
381
<refsect1 id="overview">
382
<title>OVERVIEW</title>
383
<xi:include href="overview.xml"/>
385
This program will run on the client side in the initial
386
<acronym>RAM</acronym> disk environment, and is responsible for
387
getting a password. It does this by running plugins, one of
388
which will normally be the actual client program communicating
392
<refsect1 id="plugins">
393
<title>PLUGINS</title>
395
This program will get a password by running a number of
396
<firstterm>plugins</firstterm>, which are simply executable
397
programs in a directory in the initial <acronym>RAM</acronym>
398
disk environment. The default directory is
399
<filename>/lib/mandos/plugins.d</filename>, but this can be
400
changed with the <option>--plugin-dir</option> option. The
401
plugins are started in parallel, and the first plugin to output
402
a password <emphasis>and</emphasis> exit with a successful exit
403
code will make this plugin-runner output the password from that
404
plugin, stop any other plugins, and exit.
407
<refsect2 id="writing_plugins">
408
<title>WRITING PLUGINS</title>
410
A plugin is simply a program which prints a password to its
411
standard output and then exits with a successful (zero) exit
412
status. If the exit status is not zero, any output on
413
standard output will be ignored by the plugin runner. Any
414
output on its standard error channel will simply be passed to
415
the standard error of the plugin runner, usually the system
419
If the password is a single-line, manually entered passprase,
420
a final trailing newline character should
421
<emphasis>not</emphasis> be printed.
424
The plugin will run in the initial RAM disk environment, so
425
care must be taken not to depend on any files or running
426
services not available there.
429
The plugin must exit cleanly and free all allocated resources
430
upon getting the TERM signal, since this is what the plugin
431
runner uses to stop all other plugins when one plugin has
432
output a password and exited cleanly.
435
The plugin must not use resources, like for instance reading
436
from the standard input, without knowing that no other plugin
440
It is useful, but not required, for the plugin to take the
441
<option>--debug</option> option.
446
<refsect1 id="fallback">
447
<title>FALLBACK</title>
449
If no plugins succeed, this program will, as a fallback, ask for
450
a password on the console using <citerefentry><refentrytitle
451
>getpass</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
452
and output it. This is not meant to be the normal mode of
453
operation, as there is a separate plugin for getting a password
458
263
<refsect1 id="exit_status">
459
264
<title>EXIT STATUS</title>
461
Exit status of this program is zero if no errors were
462
encountered, and otherwise not. The fallback (see <xref
463
linkend="fallback"/>) may or may not have succeeded in either
468
<refsect1 id="environment">
469
<title>ENVIRONMENT</title>
471
This program does not use any environment variables itself, it
472
only passes on its environment to all the plugins. The
473
environment passed to plugins can be modified using the
474
<option>--global-env</option> and <option>--env-for</option>
479
<refsect1 id="files">
480
270
<title>FILES</title>
485
>/conf/conf.d/mandos/plugin-runner.conf</filename></term>
488
Since this program will be run as a keyscript, there is
489
little to no opportunity to pass command line arguments
490
to it. Therefore, it will <emphasis>also</emphasis>
491
read this file and use its contents as
492
whitespace-separated command line options. Also,
493
everything from a <quote>#</quote> character to the end
494
of a line is ignored.
497
This program is meant to run in the initial RAM disk
498
environment, so that is where this file is assumed to
499
exist. The file does not need to exist in the normal
503
This file will be processed <emphasis>before</emphasis>
504
the normal command line options, so the latter can
505
override the former, if need be.
508
This file name is the default; the file to read for
509
arguments can be changed using the
510
<option>--config-file</option> option.
275
<refsect1 id="notes">
518
281
<refsect1 id="bugs">
519
282
<title>BUGS</title>
521
The <option>--config-file</option> option is ignored when
522
specified from within a configuration file.
526
287
<refsect1 id="examples">
527
288
<title>EXAMPLE</title>
530
Normal invocation needs no options:
533
<userinput>&COMMANDNAME;</userinput>
538
Run the program, but not the plugins, in debug mode:
542
<!-- do not wrap this line -->
543
<userinput>&COMMANDNAME; --debug</userinput>
549
Run all plugins, but run the <quote>foo</quote> plugin in
554
<!-- do not wrap this line -->
555
<userinput>&COMMANDNAME; --options-for=foo:--debug</userinput>
561
Run all plugins, but not the program, in debug mode:
565
<!-- do not wrap this line -->
566
<userinput>&COMMANDNAME; --global-options=--debug</userinput>
572
Run plugins from a different directory, read a different
573
configuration file, and add two options to the
574
<citerefentry><refentrytitle >mandos-client</refentrytitle>
575
<manvolnum>8mandos</manvolnum></citerefentry> plugin:
579
<!-- do not wrap this line -->
580
<userinput>&COMMANDNAME; --config-file=/etc/mandos/plugin-runner.conf --plugin-dir /usr/lib/mandos/plugins.d --options-for=mandos-client:--pubkey=/etc/keys/mandos/pubkey.txt,--seckey=/etc/keys/mandos/seckey.txt</userinput>
585
293
<refsect1 id="security">
586
294
<title>SECURITY</title>
588
This program will, when starting, try to switch to another user.
589
If it is started as root, it will succeed, and will by default
590
switch to user and group 65534, which are assumed to be
591
non-privileged. This user and group is then what all plugins
592
will be started as. Therefore, the only way to run a plugin as
593
a privileged user is to have the set-user-ID or set-group-ID bit
594
set on the plugin executable file (see <citerefentry>
595
<refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum>
599
If this program is used as a keyscript in <citerefentry
600
><refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum>
601
</citerefentry>, there is a slight risk that if this program
602
fails to work, there might be no way to boot the system except
603
for booting from another media and editing the initial RAM disk
604
image to not run this program. This is, however, unlikely,
605
since the <citerefentry><refentrytitle
606
>password-prompt</refentrytitle><manvolnum>8mandos</manvolnum>
607
</citerefentry> plugin will read a password from the console in
608
case of failure of the other plugins, and this plugin runner
609
will also, in case of catastrophic failure, itself fall back to
610
asking and outputting a password on the console (see <xref
611
linkend="fallback"/>).
615
299
<refsect1 id="see_also">
616
300
<title>SEE ALSO</title>
618
302
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
619
303
<manvolnum>8</manvolnum></citerefentry>,
620
<citerefentry><refentrytitle>crypttab</refentrytitle>
621
<manvolnum>5</manvolnum></citerefentry>,
622
<citerefentry><refentrytitle>execve</refentrytitle>
623
<manvolnum>2</manvolnum></citerefentry>,
624
304
<citerefentry><refentrytitle>mandos</refentrytitle>
625
305
<manvolnum>8</manvolnum></citerefentry>,
626
306
<citerefentry><refentrytitle>password-prompt</refentrytitle>
627
307
<manvolnum>8mandos</manvolnum></citerefentry>,
628
<citerefentry><refentrytitle>mandos-client</refentrytitle>
308
<citerefentry><refentrytitle>password-request</refentrytitle>
629
309
<manvolnum>8mandos</manvolnum></citerefentry>
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