shadow/man/newuidmap.1.xml

<?xml version="1.0" encoding="UTF-8"?>
<!--
   Copyright (c) 2013 Eric W. Biederman
   All rights reserved.
  
   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions
   are met:
   1. Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
   2. Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.
   3. The name of the copyright holders or contributors may not be used to
      endorse or promote products derived from this software without
      specific prior written permission.
  
   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
   PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT
   HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V4.5//EN"
  "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
<!-- SHADOW-CONFIG-HERE -->
]>

<refentry id='newuidmap.1'>
  <refentryinfo>
    <author>
      <firstname>Eric</firstname>
      <surname>Biederman</surname>
      <contrib>Creation, 2013</contrib>
    </author>
  </refentryinfo>
  <refmeta>
    <refentrytitle>newuidmap</refentrytitle>
    <manvolnum>1</manvolnum>
    <refmiscinfo class="sectdesc">User Commands</refmiscinfo>
    <refmiscinfo class="source">shadow-utils</refmiscinfo>
    <refmiscinfo class="version">&SHADOW_UTILS_VERSION;</refmiscinfo>
  </refmeta>
  <refnamediv id='name'>
    <refname>newuidmap</refname>
    <refpurpose>set the uid mapping of a user namespace</refpurpose>
  </refnamediv>

  <refsynopsisdiv id='synopsis'>
    <cmdsynopsis>
      <command>newuidmap</command>
      <arg choice='plain'>
	<replaceable>pid</replaceable>
      </arg>
      <arg choice='plain'>
	<replaceable>uid</replaceable>
      </arg>
      <arg choice='plain'>
	<replaceable>loweruid</replaceable>
      </arg>
      <arg choice='plain'>
	<replaceable>count</replaceable>
      </arg>
      <arg choice='opt'>
	<arg choice='plain'>
	  <replaceable>uid</replaceable>
	</arg>
	<arg choice='plain'>
	  <replaceable>loweruid</replaceable>
	</arg>
	<arg choice='plain'>
	  <replaceable>count</replaceable>
	</arg>
	<arg choice='opt'>
	  <replaceable>...</replaceable>
	</arg>
      </arg>
    </cmdsynopsis>
  </refsynopsisdiv>

  <refsect1 id='description'>
    <title>DESCRIPTION</title>
    <para>
      The <command>newuidmap</command> sets <filename>/proc/[pid]/uid_map</filename> based on its
      command line arguments and the uids allowed. The subid delegation can come either from files
      (<filename>/etc/subuid</filename>) or from the configured NSS subid module. Only one of them
      can be chosen at a time. So, for example, if the subid source is configured as NSS and
      <command>useradd</command> is executed, then the command will fail and the entry will not be
      created in <filename>/etc/subuid</filename>.
    </para>

    <para>
      Note that the root user is not exempted from the requirement for a valid
      <filename>/etc/subuid</filename> entry.
    </para>

    <para>
      After the pid argument, <command>newuidmap</command> expects sets of 3 integers:
      <variablelist>
	<varlistentry>
	  <term>uid</term>
	  <listitem>
	    <para>
	      Beginning of the range of UIDs inside the user namespace.
	    </para>
	  </listitem>
	</varlistentry>
	<varlistentry>
	  <term>loweruid</term>
	  <listitem>
	    <para>
	      Beginning of the range of UIDs outside the user namespace.
	    </para>
	  </listitem>
	</varlistentry>
	<varlistentry>
	  <term>count</term>
	  <listitem>
	    <para>
	      Length of the ranges (both inside and outside the user namespace).
	    </para>
	  </listitem>
	</varlistentry>
      </variablelist>
    </para>

    <para>
      <command>newuidmap</command> verifies that the caller is the owner
      of the process indicated by <option>pid</option> and that for each
      of the above sets, each of the UIDs in the range [loweruid,
      loweruid+count) is allowed to the caller according to
      <filename>/etc/subuid</filename> before setting
      <filename>/proc/[pid]/uid_map</filename>.
    </para>
    <para>
      Note that newuidmap may be used only once for a given process.
    </para>
  </refsect1>

  <refsect1 id='options'>
    <title>OPTIONS</title>
    <para>
      There currently are no options to the <command>newuidmap</command> command.
    </para>
    <variablelist remap='IP'>
    </variablelist>
  </refsect1>

  <refsect1 id='files'>
    <title>FILES</title>
    <variablelist>
      <varlistentry>
	<term><filename>/etc/subuid</filename></term>
	<listitem>
	  <para>List of user's subordinate user IDs.</para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term><filename>/proc/[pid]/uid_map</filename></term>
	<listitem>
	  <para>Mapping of uids from one between user namespaces.</para>
	</listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1 id='see_also'>
    <title>SEE ALSO</title>
    <para>
      <citerefentry>
	<refentrytitle>login.defs</refentrytitle><manvolnum>5</manvolnum>
      </citerefentry>,
      <citerefentry>
	<refentrytitle>newusers</refentrytitle><manvolnum>8</manvolnum>
      </citerefentry>,
      <citerefentry>
	<refentrytitle>subuid</refentrytitle><manvolnum>5</manvolnum>
      </citerefentry>,
      <citerefentry>
	<refentrytitle>useradd</refentrytitle><manvolnum>8</manvolnum>
      </citerefentry>,
      <citerefentry>
	<refentrytitle>usermod</refentrytitle><manvolnum>8</manvolnum>
      </citerefentry>,
      <citerefentry>
	<refentrytitle>userdel</refentrytitle><manvolnum>8</manvolnum>
      </citerefentry>.
    </para>
  </refsect1>
</refentry>