/mandos/release

To get this branch, use:
bzr branch http://bzr.recompile.se/loggerhead/mandos/release

« back to all changes in this revision

Viewing changes to plugins.d/usplash.xml

  • Committer: Teddy Hogeborn
  • Date: 2015-08-10 21:23:46 UTC
  • mfrom: (326 release)
  • mto: (237.7.594 trunk)
  • mto: This revision was merged to the branch mainline in revision 327.
  • Revision ID: teddy@recompile.se-20150810212346-wvobzmqnnit9q8px
Merge from release branch.

Show diffs side-by-side

added added

removed removed

Lines of Context:
 
1
<?xml version="1.0" encoding="UTF-8"?>
 
2
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
 
3
        "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
 
4
<!ENTITY COMMANDNAME "usplash">
 
5
<!ENTITY TIMESTAMP "2015-07-20">
 
6
<!ENTITY % common SYSTEM "../common.ent">
 
7
%common;
 
8
]>
 
9
 
 
10
<refentry xmlns:xi="http://www.w3.org/2001/XInclude">
 
11
  <refentryinfo>
 
12
    <title>Mandos Manual</title>
 
13
    <!-- NWalsh’s docbook scripts use this to generate the footer: -->
 
14
    <productname>Mandos</productname>
 
15
    <productnumber>&version;</productnumber>
 
16
    <date>&TIMESTAMP;</date>
 
17
    <authorgroup>
 
18
      <author>
 
19
        <firstname>Björn</firstname>
 
20
        <surname>Påhlsson</surname>
 
21
        <address>
 
22
          <email>belorn@recompile.se</email>
 
23
        </address>
 
24
      </author>
 
25
      <author>
 
26
        <firstname>Teddy</firstname>
 
27
        <surname>Hogeborn</surname>
 
28
        <address>
 
29
          <email>teddy@recompile.se</email>
 
30
        </address>
 
31
      </author>
 
32
    </authorgroup>
 
33
    <copyright>
 
34
      <year>2008</year>
 
35
      <year>2009</year>
 
36
      <year>2010</year>
 
37
      <year>2011</year>
 
38
      <year>2012</year>
 
39
      <year>2013</year>
 
40
      <year>2014</year>
 
41
      <year>2015</year>
 
42
      <holder>Teddy Hogeborn</holder>
 
43
      <holder>Björn Påhlsson</holder>
 
44
    </copyright>
 
45
    <xi:include href="../legalnotice.xml"/>
 
46
  </refentryinfo>
 
47
  
 
48
  <refmeta>
 
49
    <refentrytitle>&COMMANDNAME;</refentrytitle>
 
50
    <manvolnum>8mandos</manvolnum>
 
51
  </refmeta>
 
52
  
 
53
  <refnamediv>
 
54
    <refname><command>&COMMANDNAME;</command></refname>
 
55
    <refpurpose>Mandos plugin to use usplash to get a
 
56
    password.</refpurpose>
 
57
  </refnamediv>
 
58
  
 
59
  <refsynopsisdiv>
 
60
    <cmdsynopsis>
 
61
      <command>&COMMANDNAME;</command>
 
62
    </cmdsynopsis>
 
63
  </refsynopsisdiv>
 
64
  
 
65
  <refsect1 id="description">
 
66
    <title>DESCRIPTION</title>
 
67
    <para>
 
68
      This program prompts for a password using <citerefentry>
 
69
      <refentrytitle>usplash</refentrytitle><manvolnum>8</manvolnum>
 
70
      </citerefentry> and outputs any given password to standard
 
71
      output.  If no <citerefentry><refentrytitle
 
72
      >usplash</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 
73
      process can be found, this program will immediately exit with an
 
74
      exit code indicating failure.
 
75
    </para>
 
76
    <para>
 
77
      This program is not very useful on its own.  This program is
 
78
      really meant to run as a plugin in the <application
 
79
      >Mandos</application> client-side system, where it is used as a
 
80
      fallback and alternative to retrieving passwords from a
 
81
      <application >Mandos</application> server.
 
82
    </para>
 
83
    <para>
 
84
      If this program is killed (presumably by
 
85
      <citerefentry><refentrytitle>plugin-runner</refentrytitle>
 
86
      <manvolnum>8mandos</manvolnum></citerefentry> because some other
 
87
      plugin provided the password), it cannot tell <citerefentry>
 
88
      <refentrytitle>usplash</refentrytitle><manvolnum>8</manvolnum>
 
89
      </citerefentry> to abort requesting a password, because
 
90
      <citerefentry><refentrytitle>usplash</refentrytitle>
 
91
      <manvolnum>8</manvolnum></citerefentry> does not support this.
 
92
      Therefore, this program will then <emphasis>kill</emphasis> the
 
93
      running <citerefentry><refentrytitle>usplash</refentrytitle>
 
94
      <manvolnum>8</manvolnum></citerefentry> process and start a
 
95
      <emphasis>new</emphasis> one using the same command line
 
96
      arguments as the old one was using.
 
97
    </para>
 
98
  </refsect1>
 
99
  
 
100
  <refsect1 id="options">
 
101
    <title>OPTIONS</title>
 
102
    <para>
 
103
      This program takes no options.
 
104
    </para>
 
105
  </refsect1>
 
106
  
 
107
  <refsect1 id="exit_status">
 
108
    <title>EXIT STATUS</title>
 
109
    <para>
 
110
      If exit status is 0, the output from the program is the password
 
111
      as it was read.  Otherwise, if exit status is other than 0, the
 
112
      program was interrupted or encountered an error, and any output
 
113
      so far could be corrupt and/or truncated, and should therefore
 
114
      be ignored.
 
115
    </para>
 
116
  </refsect1>
 
117
  
 
118
  <refsect1 id="environment">
 
119
    <title>ENVIRONMENT</title>
 
120
    <variablelist>
 
121
      <varlistentry>
 
122
        <term><envar>cryptsource</envar></term>
 
123
        <term><envar>crypttarget</envar></term>
 
124
        <listitem>
 
125
          <para>
 
126
            If set, these environment variables will be assumed to
 
127
            contain the source device name and the target device
 
128
            mapper name, respectively, and will be shown as part of
 
129
            the prompt.
 
130
        </para>
 
131
        <para>
 
132
          These variables will normally be inherited from
 
133
          <citerefentry><refentrytitle>plugin-runner</refentrytitle>
 
134
          <manvolnum>8mandos</manvolnum></citerefentry>, which will
 
135
          normally have inherited them from
 
136
          <filename>/scripts/local-top/cryptroot</filename> in the
 
137
          initial <acronym>RAM</acronym> disk environment, which will
 
138
          have set them from parsing kernel arguments and
 
139
          <filename>/conf/conf.d/cryptroot</filename> (also in the
 
140
          initial RAM disk environment), which in turn will have been
 
141
          created when the initial RAM disk image was created by
 
142
          <filename
 
143
          >/usr/share/initramfs-tools/hooks/cryptroot</filename>, by
 
144
          extracting the information of the root file system from
 
145
          <filename >/etc/crypttab</filename>.
 
146
        </para>
 
147
        <para>
 
148
          This behavior is meant to exactly mirror the behavior of
 
149
          <command>askpass</command>, the default password prompter.
 
150
        </para>
 
151
        </listitem>
 
152
      </varlistentry>
 
153
    </variablelist>
 
154
  </refsect1>
 
155
  
 
156
  <refsect1 id="files">
 
157
    <title>FILES</title>
 
158
    <variablelist>
 
159
      <varlistentry>
 
160
        <term><filename>/dev/.initramfs/usplash_fifo</filename></term>
 
161
        <listitem>
 
162
          <para>
 
163
            This is the <acronym>FIFO</acronym> to where this program
 
164
            will write the commands for <citerefentry><refentrytitle
 
165
            >usplash</refentrytitle><manvolnum>8</manvolnum>
 
166
            </citerefentry>.  See <citerefentry><refentrytitle
 
167
            >fifo</refentrytitle><manvolnum>7</manvolnum>
 
168
            </citerefentry>.
 
169
          </para>
 
170
        </listitem>
 
171
      </varlistentry>
 
172
      <varlistentry>
 
173
        <term><filename>/dev/.initramfs/usplash_outfifo</filename></term>
 
174
        <listitem>
 
175
          <para>
 
176
            This is the <acronym>FIFO</acronym> where this program
 
177
            will read the password from <citerefentry><refentrytitle
 
178
            >usplash</refentrytitle><manvolnum>8</manvolnum>
 
179
            </citerefentry>.  See <citerefentry><refentrytitle
 
180
            >fifo</refentrytitle><manvolnum>7</manvolnum>
 
181
            </citerefentry>.
 
182
          </para>
 
183
        </listitem>
 
184
      </varlistentry>
 
185
      <varlistentry>
 
186
        <term><filename class="directory">/proc</filename></term>
 
187
        <listitem>
 
188
          <para>
 
189
            To find the running <citerefentry><refentrytitle
 
190
            >usplash</refentrytitle><manvolnum>8</manvolnum>
 
191
            </citerefentry>, this directory will be searched for
 
192
            numeric entries which will be assumed to be directories.
 
193
            In all those directories, the <filename>exe</filename> and
 
194
            <filename>cmdline</filename> entries will be used to
 
195
            determine the name of the running binary, effective user
 
196
            and group <abbrev>ID</abbrev>, and the command line
 
197
            arguments.  See <citerefentry><refentrytitle
 
198
            >proc</refentrytitle><manvolnum>5</manvolnum>
 
199
            </citerefentry>.
 
200
          </para>
 
201
        </listitem>
 
202
      </varlistentry>
 
203
      <varlistentry>
 
204
        <term><filename>/sbin/usplash</filename></term>
 
205
        <listitem>
 
206
          <para>
 
207
            This is the name of the binary which will be searched for
 
208
            in the process list.  See <citerefentry><refentrytitle
 
209
            >usplash</refentrytitle><manvolnum>8</manvolnum>
 
210
            </citerefentry>.
 
211
          </para>
 
212
        </listitem>
 
213
      </varlistentry>
 
214
    </variablelist>
 
215
  </refsect1>
 
216
  
 
217
  <refsect1 id="bugs">
 
218
    <title>BUGS</title>
 
219
    <para>
 
220
      Killing <citerefentry><refentrytitle>usplash</refentrytitle>
 
221
      <manvolnum>8</manvolnum></citerefentry> and starting a new one
 
222
      is ugly, but necessary as long as it does not support aborting a
 
223
      password request.
 
224
    </para>
 
225
  </refsect1>
 
226
  
 
227
  <refsect1 id="example">
 
228
    <title>EXAMPLE</title>
 
229
    <para>
 
230
      Note that normally, this program will not be invoked directly,
 
231
      but instead started by the Mandos <citerefentry><refentrytitle
 
232
      >plugin-runner</refentrytitle><manvolnum>8mandos</manvolnum>
 
233
      </citerefentry>.
 
234
    </para>
 
235
    <informalexample>
 
236
      <para>
 
237
        This program takes no options.
 
238
      </para>
 
239
      <para>
 
240
        <userinput>&COMMANDNAME;</userinput>
 
241
      </para>
 
242
    </informalexample>
 
243
  </refsect1>
 
244
  
 
245
  <refsect1 id="security">
 
246
    <title>SECURITY</title>
 
247
    <para>
 
248
      If this program is killed by a signal, it will kill the process
 
249
      <abbrev>ID</abbrev> which at the start of this program was
 
250
      determined to run <citerefentry><refentrytitle
 
251
      >usplash</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 
252
      as root (see also <xref linkend="files"/>).  There is a very
 
253
      slight risk that, in the time between those events, that process
 
254
      <abbrev>ID</abbrev> was freed and then taken up by another
 
255
      process; the wrong process would then be killed.  Now, this
 
256
      program can only be killed by the user who started it; see
 
257
      <citerefentry><refentrytitle>plugin-runner</refentrytitle>
 
258
      <manvolnum>8mandos</manvolnum></citerefentry>.  This program
 
259
      should therefore be started by a completely separate
 
260
      non-privileged user, and no other programs should be allowed to
 
261
      run as that special user.  This means that it is not recommended
 
262
      to use the user "nobody" to start this program, as other
 
263
      possibly less trusted programs could be running as "nobody", and
 
264
      they would then be able to kill this program, triggering the
 
265
      killing of the process <abbrev>ID</abbrev> which may or may not
 
266
      be <citerefentry><refentrytitle>usplash</refentrytitle>
 
267
      <manvolnum>8</manvolnum></citerefentry>.
 
268
    </para>
 
269
    <para>
 
270
      The only other thing that could be considered worthy of note is
 
271
      this:  This program is meant to be run by <citerefentry>
 
272
      <refentrytitle>plugin-runner</refentrytitle><manvolnum
 
273
      >8mandos</manvolnum></citerefentry>, and will, when run
 
274
      standalone, outside, in a normal environment, immediately output
 
275
      on its standard output any presumably secret password it just
 
276
      received.  Therefore, when running this program standalone
 
277
      (which should never normally be done), take care not to type in
 
278
      any real secret password by force of habit, since it would then
 
279
      immediately be shown as output.
 
280
    </para>
 
281
  </refsect1>
 
282
  
 
283
  <refsect1 id="see_also">
 
284
    <title>SEE ALSO</title>
 
285
    <para>
 
286
      <citerefentry><refentrytitle>intro</refentrytitle>
 
287
      <manvolnum>8mandos</manvolnum></citerefentry>,
 
288
      <citerefentry><refentrytitle>crypttab</refentrytitle>
 
289
      <manvolnum>5</manvolnum></citerefentry>,
 
290
      <citerefentry><refentrytitle>fifo</refentrytitle>
 
291
      <manvolnum>7</manvolnum></citerefentry>,
 
292
      <citerefentry><refentrytitle>plugin-runner</refentrytitle>
 
293
      <manvolnum>8mandos</manvolnum></citerefentry>,
 
294
      <citerefentry><refentrytitle>proc</refentrytitle>
 
295
      <manvolnum>5</manvolnum></citerefentry>,
 
296
      <citerefentry><refentrytitle>usplash</refentrytitle>
 
297
      <manvolnum>8</manvolnum></citerefentry>
 
298
    </para>
 
299
  </refsect1>
 
300
</refentry>
 
301
<!-- Local Variables: -->
 
302
<!-- time-stamp-start: "<!ENTITY TIMESTAMP [\"']" -->
 
303
<!-- time-stamp-end: "[\"']>" -->
 
304
<!-- time-stamp-format: "%:y-%02m-%02d" -->
 
305
<!-- End: -->