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|
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
<!ENTITY COMMANDNAME "plugin-runner">
<!ENTITY TIMESTAMP "2023-04-30">
<!ENTITY % common SYSTEM "common.ent">
%common;
]>
<refentry xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>Mandos Manual</title>
<!-- Nwalsh’s docbook scripts use this to generate the footer: -->
<productname>Mandos</productname>
<productnumber>&version;</productnumber>
<date>&TIMESTAMP;</date>
<authorgroup>
<author>
<firstname>Björn</firstname>
<surname>Påhlsson</surname>
<address>
<email>belorn@recompile.se</email>
</address>
</author>
<author>
<firstname>Teddy</firstname>
<surname>Hogeborn</surname>
<address>
<email>teddy@recompile.se</email>
</address>
</author>
</authorgroup>
<copyright>
<year>2008</year>
<year>2009</year>
<year>2010</year>
<year>2011</year>
<year>2012</year>
<year>2013</year>
<year>2014</year>
<year>2015</year>
<year>2016</year>
<year>2017</year>
<year>2018</year>
<year>2019</year>
<holder>Teddy Hogeborn</holder>
<holder>Björn Påhlsson</holder>
</copyright>
<xi:include href="legalnotice.xml"/>
</refentryinfo>
<refmeta>
<refentrytitle>&COMMANDNAME;</refentrytitle>
<manvolnum>8mandos</manvolnum>
</refmeta>
<refnamediv>
<refname><command>&COMMANDNAME;</command></refname>
<refpurpose>
Run Mandos plugins, pass data from first to succeed.
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>&COMMANDNAME;</command>
<group rep="repeat">
<arg choice="plain"><option>--global-env=<replaceable
>ENV</replaceable><literal>=</literal><replaceable
>value</replaceable></option></arg>
<arg choice="plain"><option>-G
<replaceable>ENV</replaceable><literal>=</literal><replaceable
>value</replaceable> </option></arg>
</group>
<sbr/>
<group rep="repeat">
<arg choice="plain"><option>--env-for=<replaceable
>PLUGIN</replaceable><literal>:</literal><replaceable
>ENV</replaceable><literal>=</literal><replaceable
>value</replaceable></option></arg>
<arg choice="plain"><option>-E<replaceable>
PLUGIN</replaceable><literal>:</literal><replaceable
>ENV</replaceable><literal>=</literal><replaceable
>value</replaceable> </option></arg>
</group>
<sbr/>
<group rep="repeat">
<arg choice="plain"><option>--global-options=<replaceable
>OPTIONS</replaceable></option></arg>
<arg choice="plain"><option>-g<replaceable>
OPTIONS</replaceable> </option></arg>
</group>
<sbr/>
<group rep="repeat">
<arg choice="plain"><option>--options-for=<replaceable
>PLUGIN</replaceable><literal>:</literal><replaceable
>OPTIONS</replaceable></option></arg>
<arg choice="plain"><option>-o<replaceable>
PLUGIN</replaceable><literal>:</literal><replaceable
>OPTIONS</replaceable> </option></arg>
</group>
<sbr/>
<group rep="repeat">
<arg choice="plain"><option>--disable=<replaceable
>PLUGIN</replaceable></option></arg>
<arg choice="plain"><option>-d
<replaceable>PLUGIN</replaceable> </option></arg>
</group>
<sbr/>
<group rep="repeat">
<arg choice="plain"><option>--enable=<replaceable
>PLUGIN</replaceable></option></arg>
<arg choice="plain"><option>-e
<replaceable>PLUGIN</replaceable> </option></arg>
</group>
<sbr/>
<arg><option>--groupid=<replaceable
>ID</replaceable></option></arg>
<sbr/>
<arg><option>--userid=<replaceable
>ID</replaceable></option></arg>
<sbr/>
<arg><option>--plugin-dir=<replaceable
>DIRECTORY</replaceable></option></arg>
<sbr/>
<arg><option>--plugin-helper-dir=<replaceable
>DIRECTORY</replaceable></option></arg>
<sbr/>
<arg><option>--config-file=<replaceable
>FILE</replaceable></option></arg>
<sbr/>
<arg><option>--debug</option></arg>
</cmdsynopsis>
<cmdsynopsis>
<command>&COMMANDNAME;</command>
<group choice="req">
<arg choice="plain"><option>--help</option></arg>
<arg choice="plain"><option>-?</option></arg>
</group>
</cmdsynopsis>
<cmdsynopsis>
<command>&COMMANDNAME;</command>
<arg choice="plain"><option>--usage</option></arg>
</cmdsynopsis>
<cmdsynopsis>
<command>&COMMANDNAME;</command>
<group choice="req">
<arg choice="plain"><option>--version</option></arg>
<arg choice="plain"><option>-V</option></arg>
</group>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1 id="description">
<title>DESCRIPTION</title>
<para>
<command>&COMMANDNAME;</command> is a program which is meant to
be specified as a <quote>keyscript</quote> for the root disk in
<citerefentry><refentrytitle>crypttab</refentrytitle>
<manvolnum>5</manvolnum></citerefentry>. The aim of this
program is therefore to output a password, which then
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
<manvolnum>8</manvolnum></citerefentry> will use to unlock the
root disk.
</para>
<para>
This program is not meant to be invoked directly, but can be in
order to test it. Note that any password obtained will simply
be output on standard output.
</para>
</refsect1>
<refsect1 id="purpose">
<title>PURPOSE</title>
<para>
The purpose of this is to enable <emphasis>remote and unattended
rebooting</emphasis> of client host computer with an
<emphasis>encrypted root file system</emphasis>. See <xref
linkend="overview"/> for details.
</para>
</refsect1>
<refsect1>
<title>OPTIONS</title>
<variablelist>
<varlistentry>
<term><option>--global-env
<replaceable>ENV</replaceable><literal>=</literal><replaceable
>value</replaceable></option></term>
<term><option>-G
<replaceable>ENV</replaceable><literal>=</literal><replaceable
>value</replaceable></option></term>
<listitem>
<para>
This option will add an environment variable setting to
all plugins. This will override any inherited environment
variable.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--env-for
<replaceable>PLUGIN</replaceable><literal>:</literal
><replaceable>ENV</replaceable><literal>=</literal
><replaceable>value</replaceable></option></term>
<term><option>-E
<replaceable>PLUGIN</replaceable><literal>:</literal
><replaceable>ENV</replaceable><literal>=</literal
><replaceable>value</replaceable></option></term>
<listitem>
<para>
This option will add an environment variable setting to
the <replaceable>PLUGIN</replaceable> plugin. This will
override any inherited environment variables or
environment variables specified using
<option>--global-env</option>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--global-options
<replaceable>OPTIONS</replaceable></option></term>
<term><option>-g
<replaceable>OPTIONS</replaceable></option></term>
<listitem>
<para>
Pass some options to <emphasis>all</emphasis> plugins.
<replaceable>OPTIONS</replaceable> is a comma separated
list of options. This is not a very useful option, except
for specifying the <quote><option>--debug</option></quote>
option to all plugins.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--options-for
<replaceable>PLUGIN</replaceable><literal>:</literal
><replaceable>OPTION</replaceable></option></term>
<term><option>-o
<replaceable>PLUGIN</replaceable><literal>:</literal
><replaceable>OPTION</replaceable></option></term>
<listitem>
<para>
Pass some options to a specific plugin. <replaceable
>PLUGIN</replaceable> is the name (file basename) of a
plugin, and <replaceable>OPTIONS</replaceable> is a comma
separated list of options.
</para>
<para>
Note that since options are not split on whitespace, the
way to pass, to the plugin
<quote><filename>foo</filename></quote>, the option
<option>--bar</option> with the option argument
<quote>baz</quote> is either
<userinput>--options-for=foo:--bar=baz</userinput> or
<userinput>--options-for=foo:--bar,baz</userinput>. Using
<userinput>--options-for="foo:--bar baz"</userinput>. will
<emphasis>not</emphasis> work.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--disable
<replaceable>PLUGIN</replaceable></option></term>
<term><option>-d
<replaceable>PLUGIN</replaceable></option></term>
<listitem>
<para>
Disable the plugin named
<replaceable>PLUGIN</replaceable>. The plugin will not be
started.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--enable
<replaceable>PLUGIN</replaceable></option></term>
<term><option>-e
<replaceable>PLUGIN</replaceable></option></term>
<listitem>
<para>
Re-enable the plugin named
<replaceable>PLUGIN</replaceable>. This is only useful to
undo a previous <option>--disable</option> option, maybe
from the configuration file.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--groupid
<replaceable>ID</replaceable></option></term>
<listitem>
<para>
Change to group ID <replaceable>ID</replaceable> on
startup. The default is 65534. All plugins will be
started using this group ID. <emphasis>Note:</emphasis>
This must be a number, not a name.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--userid
<replaceable>ID</replaceable></option></term>
<listitem>
<para>
Change to user ID <replaceable>ID</replaceable> on
startup. The default is 65534. All plugins will be
started using this user ID. <emphasis>Note:</emphasis>
This must be a number, not a name.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--plugin-dir
<replaceable>DIRECTORY</replaceable></option></term>
<listitem>
<para>
Specify a different plugin directory. The default is
<filename>/lib/mandos/plugins.d</filename>, which will
exist in the initial <acronym>RAM</acronym> disk
environment.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--plugin-helper-dir
<replaceable>DIRECTORY</replaceable></option></term>
<listitem>
<para>
Specify a different plugin helper directory. The default
is <filename>/lib/mandos/plugin-helpers</filename>, which
will exist in the initial <acronym>RAM</acronym> disk
environment. (This will simply be passed to all plugins
via the <envar>MANDOSPLUGINHELPERDIR</envar> environment
variable. See <xref linkend="writing_plugins"/>)
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--config-file
<replaceable>FILE</replaceable></option></term>
<listitem>
<para>
Specify a different file to read additional options from.
See <xref linkend="files"/>. Other command line options
will override options specified in the file.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--debug</option></term>
<listitem>
<para>
Enable debug mode. This will enable a lot of output to
standard error about what the program is doing. The
program will still perform all other functions normally.
The default is to <emphasis>not</emphasis> run in debug
mode.
</para>
<para>
The plugins will <emphasis>not</emphasis> be affected by
this option. Use
<userinput><option>--global-options=--debug</option></userinput>
if complete debugging eruption is desired.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--help</option></term>
<term><option>-?</option></term>
<listitem>
<para>
Gives a help message about options and their meanings.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--usage</option></term>
<listitem>
<para>
Gives a short usage message.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--version</option></term>
<term><option>-V</option></term>
<listitem>
<para>
Prints the program version.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id="overview">
<title>OVERVIEW</title>
<xi:include href="overview.xml"/>
<para>
This program will run on the client side in the initial
<acronym>RAM</acronym> disk environment, and is responsible for
getting a password. It does this by running plugins, one of
which will normally be the actual client program communicating
with the server.
</para>
</refsect1>
<refsect1 id="plugins">
<title>PLUGINS</title>
<para>
This program will get a password by running a number of
<firstterm>plugins</firstterm>, which are executable programs in
a directory in the initial <acronym>RAM</acronym> disk
environment. The default directory is
<filename>/lib/mandos/plugins.d</filename>, but this can be
changed with the <option>--plugin-dir</option> option. The
plugins are started in parallel, and the first plugin to output
a password <emphasis>and</emphasis> exit with a successful exit
code will make this plugin-runner output the password from that
plugin, stop any other plugins, and exit.
</para>
<refsect2 id="writing_plugins">
<title>WRITING PLUGINS</title>
<para>
A plugin is an executable program which prints a password to
its standard output and then exits with a successful (zero)
exit status. If the exit status is not zero, any output on
standard output will be ignored by the plugin runner. Any
output on its standard error channel will simply be passed to
the standard error of the plugin runner, usually the system
console.
</para>
<para>
If the password is a single-line, manually entered passprase,
a final trailing newline character should
<emphasis>not</emphasis> be printed.
</para>
<para>
The plugin will run in the initial RAM disk environment, so
care must be taken not to depend on any files or running
services not available there. Any helper executables required
by the plugin (which are not in the <envar>PATH</envar>) can
be placed in the plugin helper directory, the name of which
will be made available to the plugin via the
<envar>MANDOSPLUGINHELPERDIR</envar> environment variable.
</para>
<para>
The plugin must exit cleanly and free all allocated resources
upon getting the TERM signal, since this is what the plugin
runner uses to stop all other plugins when one plugin has
output a password and exited cleanly.
</para>
<para>
The plugin must not use resources, like for instance reading
from the standard input, without knowing that no other plugin
is also using it.
</para>
<para>
It is useful, but not required, for the plugin to take the
<option>--debug</option> option.
</para>
</refsect2>
</refsect1>
<refsect1 id="fallback">
<title>FALLBACK</title>
<para>
If no plugins succeed, this program will, as a fallback, ask for
a password on the console using <citerefentry><refentrytitle
>getpass</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
and output it. This is not meant to be the normal mode of
operation, as there is a separate plugin for getting a password
from the console.
</para>
</refsect1>
<refsect1 id="exit_status">
<title>EXIT STATUS</title>
<para>
Exit status of this program is zero if no errors were
encountered, and otherwise not. The fallback (see <xref
linkend="fallback"/>) may or may not have succeeded in either
case.
</para>
</refsect1>
<refsect1 id="environment">
<title>ENVIRONMENT</title>
<para>
This program does not use any environment variables itself, it
only passes on its environment to all the plugins. The
environment passed to plugins can be modified using the
<option>--global-env</option> and <option>--env-for</option>
options. Also, the <option>--plugin-helper-dir</option> option
will affect the environment variable
<envar>MANDOSPLUGINHELPERDIR</envar> for the plugins.
</para>
</refsect1>
<refsect1 id="files">
<title>FILES</title>
<para>
<variablelist>
<varlistentry>
<term><filename
>/conf/conf.d/mandos/plugin-runner.conf</filename></term>
<listitem>
<para>
Since this program will be run as a keyscript, there is
little to no opportunity to pass command line arguments
to it. Therefore, it will <emphasis>also</emphasis>
read this file and use its contents as
whitespace-separated command line options. Also,
everything from a <quote>#</quote> character to the end
of a line is ignored.
</para>
<para>
This program is meant to run in the initial RAM disk
environment, so that is where this file is assumed to
exist. The file does not need to exist in the normal
file system.
</para>
<para>
This file will be processed <emphasis>before</emphasis>
the normal command line options, so the latter can
override the former, if need be.
</para>
<para>
This file name is the default; the file to read for
arguments can be changed using the
<option>--config-file</option> option.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename class="directory"
>/lib/mandos/plugins.d</filename></term>
<listitem>
<para>
The default plugin directory; can be changed by the
<option>--plugin-dir</option> option.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename class="directory"
>/lib/mandos/plugin-helpers</filename></term>
<listitem>
<para>
The default plugin helper directory; can be changed by
the <option>--plugin-helper-dir</option> option.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect1>
<refsect1 id="bugs">
<title>BUGS</title>
<para>
The <option>--config-file</option> option is ignored when
specified from within a configuration file.
</para>
<xi:include href="bugs.xml"/>
</refsect1>
<refsect1 id="examples">
<title>EXAMPLE</title>
<informalexample>
<para>
Normal invocation needs no options:
</para>
<para>
<userinput>&COMMANDNAME;</userinput>
</para>
</informalexample>
<informalexample>
<para>
Run the program, but not the plugins, in debug mode:
</para>
<para>
<!-- do not wrap this line -->
<userinput>&COMMANDNAME; --debug</userinput>
</para>
</informalexample>
<informalexample>
<para>
Run all plugins, but run the <quote>foo</quote> plugin in
debug mode:
</para>
<para>
<!-- do not wrap this line -->
<userinput>&COMMANDNAME; --options-for=foo:--debug</userinput>
</para>
</informalexample>
<informalexample>
<para>
Run all plugins, but not the program, in debug mode:
</para>
<para>
<!-- do not wrap this line -->
<userinput>&COMMANDNAME; --global-options=--debug</userinput>
</para>
</informalexample>
<informalexample>
<para>
Read a different configuration file, run plugins from a
different directory, specify an alternate plugin helper
directory and add four options to the
<citerefentry><refentrytitle >mandos-client</refentrytitle>
<manvolnum>8mandos</manvolnum></citerefentry> plugin:
</para>
<para>
<!-- do not wrap this line -->
<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,​--tls-pubkey=tls-pubkey.pem,​--tls-privkey=tls-privkey.pem</userinput>
</para>
</informalexample>
</refsect1>
<refsect1 id="security">
<title>SECURITY</title>
<para>
This program will, when starting, try to switch to another user.
If it is started as root, it will succeed, and will by default
switch to user and group 65534, which are assumed to be
non-privileged. This user and group is then what all plugins
will be started as. Therefore, the only way to run a plugin as
a privileged user is to have the set-user-ID or set-group-ID bit
set on the plugin executable file (see <citerefentry>
<refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum>
</citerefentry>).
</para>
<para>
If this program is used as a keyscript in <citerefentry
><refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum>
</citerefentry>, there is a slight risk that if this program
fails to work, there might be no way to boot the system except
for booting from another media and editing the initial RAM disk
image to not run this program. This is, however, unlikely,
since the <citerefentry><refentrytitle
>password-prompt</refentrytitle><manvolnum>8mandos</manvolnum>
</citerefentry> plugin will read a password from the console in
case of failure of the other plugins, and this plugin runner
will also, in case of catastrophic failure, itself fall back to
asking and outputting a password on the console (see <xref
linkend="fallback"/>).
</para>
</refsect1>
<refsect1 id="see_also">
<title>SEE ALSO</title>
<para>
<citerefentry><refentrytitle>intro</refentrytitle>
<manvolnum>8mandos</manvolnum></citerefentry>,
<citerefentry><refentrytitle>cryptsetup</refentrytitle>
<manvolnum>8</manvolnum></citerefentry>,
<citerefentry><refentrytitle>crypttab</refentrytitle>
<manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>execve</refentrytitle>
<manvolnum>2</manvolnum></citerefentry>,
<citerefentry><refentrytitle>mandos</refentrytitle>
<manvolnum>8</manvolnum></citerefentry>,
<citerefentry><refentrytitle>password-prompt</refentrytitle>
<manvolnum>8mandos</manvolnum></citerefentry>,
<citerefentry><refentrytitle>mandos-client</refentrytitle>
<manvolnum>8mandos</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>
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