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Diffstat (limited to 'modules/pam_namespace/pam_namespace.8.xml')
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diff --git a/modules/pam_namespace/pam_namespace.8.xml b/modules/pam_namespace/pam_namespace.8.xml new file mode 100644 index 0000000..f0f80d3 --- /dev/null +++ b/modules/pam_namespace/pam_namespace.8.xml @@ -0,0 +1,418 @@ +<?xml version="1.0" encoding="ISO-8859-1"?> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"> + +<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, insert the + following line, before exit 0, in /etc/gdm/PostSession/Default: + </para> + + <para> + /usr/sbin/gdm-safe-restart + </para> + + <para> + This allows gdm to restart after each session and appropriately adjust + namespaces of display manager and the X server. If polyinstantiation + of /tmp is desired along with the graphical environment, then additional + configuration changes are needed to address the interaction of X server + and font server namespaces with their use of /tmp to create + communication sockets. Please use the initialization script + <filename>/etc/security/namespace.init</filename> to ensure that + the X server and its clients can appropriately access the + communication socket X0. Please refer to the sample instructions + provided in the comment section of the instance initialization script + <filename>/etc/security/namespace.init</filename>. In addition, + perform the following changes to use graphical environment with + polyinstantiation of /tmp: + </para> + + <para> + <literallayout> + 1. Disable the use of font server by commenting out "FontPath" + line in /etc/X11/xorg.conf. If you do want to use the font server + then you will have to augment the instance initialization + script to appropriately provide /tmp/.font-unix from the + polyinstantiated /tmp. + 2. Ensure that the gdm service is setup to use pam_namespace, + as described above, by modifying /etc/pam.d/gdm. + 3. Ensure that the display manager is configured to restart X server + with each new session. This default setup can be verified by + making sure that /usr/share/gdm/defaults.conf contains + "AlwaysRestartServer=true", and it is not overridden by + /etc/gdm/custom.conf. + </literallayout> + </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> |