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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
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<refentry id='pam_namespace'>
<refmeta>
<refentrytitle>pam_namespace</refentrytitle>
<manvolnum>8</manvolnum>
<refmiscinfo class='setdesc'>Linux-PAM Manual</refmiscinfo>
</refmeta>
<refnamediv id='pam_namespace-name'>
<refname>pam_namespace</refname>
<refpurpose>
PAM module for configuring namespace for a session
</refpurpose>
</refnamediv>
<!-- body begins here -->
<refsynopsisdiv>
<cmdsynopsis id="pam_namespace-cmdsynopsis">
<command>pam_namespace.so</command>
<arg choice="opt">
debug
</arg>
<arg choice="opt">
unmnt_remnt
</arg>
<arg choice="opt">
unmnt_only
</arg>
<arg choice="opt">
require_selinux
</arg>
<arg choice="opt">
gen_hash
</arg>
<arg choice="opt">
ignore_config_error
</arg>
<arg choice="opt">
ignore_instance_parent_mode
</arg>
<arg choice="opt">
unmount_on_close
</arg>
<arg choice="opt">
use_current_context
</arg>
<arg choice="opt">
use_default_context
</arg>
<arg choice="opt">
mount_private
</arg>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1 id="pam_namespace-description">
<title>DESCRIPTION</title>
<para>
The pam_namespace PAM module sets up a private namespace for a session
with polyinstantiated directories. A polyinstantiated directory
provides a different instance of itself based on user name, or when
using SELinux, user name, security context or both. If an executable
script <filename>/etc/security/namespace.init</filename> exists, it
is used to initialize the instance directory after it is set up
and mounted on the polyinstantiated directory. The script receives the
polyinstantiated directory path, the instance directory path, flag
whether the instance directory was newly created (0 for no, 1 for yes),
and the user name as its arguments.
</para>
<para>
The pam_namespace module disassociates the session namespace from
the parent namespace. Any mounts/unmounts performed in the parent
namespace, such as mounting of devices, are not reflected in the
session namespace. To propagate selected mount/unmount events from
the parent namespace into the disassociated session namespace, an
administrator may use the special shared-subtree feature. For
additional information on shared-subtree feature, please refer to
the mount(8) man page and the shared-subtree description at
http://lwn.net/Articles/159077 and http://lwn.net/Articles/159092.
</para>
</refsect1>
<refsect1 id="pam_namespace-options">
<title>OPTIONS</title>
<variablelist>
<varlistentry>
<term>
<option>debug</option>
</term>
<listitem>
<para>
A lot of debug information is logged using syslog
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>unmnt_remnt</option>
</term>
<listitem>
<para>
For programs such as su and newrole, the login
session has already setup a polyinstantiated
namespace. For these programs, polyinstantiation
is performed based on new user id or security
context, however the command first needs to
undo the polyinstantiation performed by login.
This argument instructs the command to
first undo previous polyinstantiation before
proceeding with new polyinstantiation based on
new id/context
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>unmnt_only</option>
</term>
<listitem>
<para>
For trusted programs that want to undo any
existing bind mounts and process instance
directories on their own, this argument allows
them to unmount currently mounted instance
directories
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>require_selinux</option>
</term>
<listitem>
<para>
If selinux is not enabled, return failure
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>gen_hash</option>
</term>
<listitem>
<para>
Instead of using the security context string
for the instance name, generate and use its
md5 hash.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>ignore_config_error</option>
</term>
<listitem>
<para>
If a line in the configuration file corresponding
to a polyinstantiated directory contains format
error, skip that line process the next line.
Without this option, pam will return an error
to the calling program resulting in termination
of the session.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>ignore_instance_parent_mode</option>
</term>
<listitem>
<para>
Instance parent directories by default are expected to have
the restrictive mode of 000. Using this option, an administrator
can choose to ignore the mode of the instance parent. This option
should be used with caution as it will reduce security and
isolation goals of the polyinstantiation mechanism.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>unmount_on_close</option>
</term>
<listitem>
<para>
Explicitly unmount the polyinstantiated directories instead
of relying on automatic namespace destruction after the last
process in a namespace exits. This option should be used
only in case it is ensured by other means that there cannot be
any processes running in the private namespace left after the
session close. It is also useful only in case there are
multiple pam session calls in sequence from the same process.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>use_current_context</option>
</term>
<listitem>
<para>
Useful for services which do not change the SELinux context
with setexeccon call. The module will use the current SELinux
context of the calling process for the level and context
polyinstantiation.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>use_default_context</option>
</term>
<listitem>
<para>
Useful for services which do not use pam_selinux for changing
the SELinux context with setexeccon call. The module will use
the default SELinux context of the user for the level and context
polyinstantiation.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>mount_private</option>
</term>
<listitem>
<para>
This option can be used on systems where the / mount point or
its submounts are made shared (for example with a
<command>mount --make-rshared /</command> command).
The module will mark the whole directory tree so any mount and
unmount operations in the polyinstantiation namespace are private.
Normally the pam_namespace will try to detect the
shared / mount point and make the polyinstantiated directories
private automatically. This option has to be used just when
only a subtree is shared and / is not.
</para>
<para>
Note that mounts and unmounts done in the private namespace will not
affect the parent namespace if this option is used or when the
shared / mount point is autodetected.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id="pam_namespace-types">
<title>MODULE TYPES PROVIDED</title>
<para>
Only the <option>session</option> module type is provided.
The module must not be called from multithreaded processes.
</para>
</refsect1>
<refsect1 id="pam_namespace-return_values">
<title>RETURN VALUES</title>
<variablelist>
<varlistentry>
<term>PAM_SUCCESS</term>
<listitem>
<para>
Namespace setup was successful.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>PAM_SERVICE_ERR</term>
<listitem>
<para>
Unexpected system error occurred while setting up namespace.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>PAM_SESSION_ERR</term>
<listitem>
<para>
Unexpected namespace configuration error occurred.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id="pam_namespace-files">
<title>FILES</title>
<variablelist>
<varlistentry>
<term><filename>/etc/security/namespace.conf</filename></term>
<listitem>
<para>Main configuration file</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>/etc/security/namespace.d</filename></term>
<listitem>
<para>Directory for additional configuration files</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>/etc/security/namespace.init</filename></term>
<listitem>
<para>Init script for instance directories</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id="pam_namespace-examples">
<title>EXAMPLES</title>
<para>
For the <service>s you need polyinstantiation (login for example)
put the following line in /etc/pam.d/<service> as the last line for
session group:
</para>
<para>
session required pam_namespace.so [arguments]
</para>
<para>
To use polyinstantiation with graphical display manager gdm, please refer
to gdm's documentation.
</para>
</refsect1>
<refsect1 id="pam_namespace-see_also">
<title>SEE ALSO</title>
<para>
<citerefentry>
<refentrytitle>namespace.conf</refentrytitle><manvolnum>5</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>pam.d</refentrytitle><manvolnum>5</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>pam</refentrytitle><manvolnum>8</manvolnum>
</citerefentry>.
</para>
</refsect1>
<refsect1 id="pam_namespace-authors">
<title>AUTHORS</title>
<para>
The namespace setup scheme was designed by Stephen Smalley, Janak Desai
and Chad Sellers.
The pam_namespace PAM module was developed by Janak Desai <janak@us.ibm.com>,
Chad Sellers <csellers@tresys.com> and Steve Grubb <sgrubb@redhat.com>.
Additional improvements by Xavier Toth <txtoth@gmail.com> and Tomas Mraz
<tmraz@redhat.com>.
</para>
</refsect1>
</refentry>