forked from extern/shorewall_code
a44e4a46f8
git-svn-id: https://shorewall.svn.sourceforge.net/svnroot/shorewall/trunk@1143 fbd18981-670d-0410-9b5c-8dc0c1a9a2bb
209 lines
7.1 KiB
XML
209 lines
7.1 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
|
|
<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
|
|
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
|
|
<article id="UserSets">
|
|
<!--$Id$-->
|
|
|
|
<articleinfo>
|
|
<title>Controlling Output Traffic by UID/GID</title>
|
|
|
|
<authorgroup>
|
|
<author>
|
|
<firstname>Tom</firstname>
|
|
|
|
<surname>Eastep</surname>
|
|
</author>
|
|
</authorgroup>
|
|
|
|
<pubdate>2003-09-19</pubdate>
|
|
|
|
<copyright>
|
|
<year>2003</year>
|
|
|
|
<holder>Thomas M. Eastep</holder>
|
|
</copyright>
|
|
|
|
<legalnotice>
|
|
<para>Permission is granted to copy, distribute and/or modify this
|
|
document under the terms of the GNU Free Documentation License, Version
|
|
1.2 or any later version published by the Free Software Foundation; with
|
|
no Invariant Sections, with no Front-Cover, and with no Back-Cover
|
|
Texts. A copy of the license is included in the section entitled
|
|
<quote><ulink url="GnuCopyright.htm">GNU Free Documentation License</ulink></quote>.</para>
|
|
</legalnotice>
|
|
</articleinfo>
|
|
|
|
<section>
|
|
<title>Overview</title>
|
|
|
|
<para>This capability was added in Shorewall release 1.4.7.</para>
|
|
|
|
<para>Netfilter provides the capability to filter packets generated on the
|
|
firewall system by User Id and/or Group Id. Shorewall provides two
|
|
separate but related ways to use this Netfilter capability:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<para>Shorewall allows you to define collections of users called
|
|
<quote><link linkend="UserSet">User Sets</link></quote> and then to
|
|
restrict certain rules in /etc/shorewall/rules to a given User Set.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>Shorewall also allows you to restrict a given <link
|
|
linkend="Rule">rule</link> to a particular user and/or group.</para>
|
|
</listitem>
|
|
</itemizedlist>
|
|
|
|
<para>Since only packets created by programs running on the Shorewall box
|
|
itself, only rules whose SOURCE is the firewall ($FW) may be restricted
|
|
using either of the facilities.</para>
|
|
</section>
|
|
|
|
<section id="UserSet">
|
|
<title>User Sets</title>
|
|
|
|
<para>Given the way that this facility is implemented in Shorewall, it is
|
|
not possible to control logging of individual rules using a User Set and
|
|
logging is rather specified on the User Set itself.</para>
|
|
|
|
<para>User Sets are defined in the /etc/shorewall/usersets file. Columns
|
|
in that file include:</para>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term>USERSET</term>
|
|
|
|
<listitem>
|
|
<para>The name of a User Set. Must be a legal shell identifier of no
|
|
more than six (6) characters in length.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term>REJECT</term>
|
|
|
|
<listitem>
|
|
<para>Log level for connections rejected for this User Set.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term>ACCEPT</term>
|
|
|
|
<listitem>
|
|
<para>Log level for connections accepted for this User Set.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term>DROP</term>
|
|
|
|
<listitem>
|
|
<para>Log level for connections dropped for this User Set.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
|
|
<para>In the REJECT and ACCEPT columns, if you don't want to specify a
|
|
value in the column but you want to specify a value in a following column,
|
|
you may enter <quote>-</quote>.</para>
|
|
|
|
<para>Users and/or groups are added to User Sets using the
|
|
/etc/shorewall/users file. Columns in that file are:</para>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term>USERSET</term>
|
|
|
|
<listitem>
|
|
<para>The name of a User Set defined in /etc/shorewall/usersets.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term>USER</term>
|
|
|
|
<listitem>
|
|
<para>The name of a user defined on the system or a user number.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term>GROUP</term>
|
|
|
|
<listitem>
|
|
<para>The name of a group defined on the system or a number.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
|
|
<para>Only one of the USER and GROUP column needs to be non-empty. If you
|
|
wish to specify a GROUP but not a USER, enter <quote>-</quote> in the user
|
|
column.</para>
|
|
|
|
<para>If both USER and GROUP are specified then only programs running
|
|
under that USER:GROUP pair will match rules specifying the User Set named
|
|
in the USERSET column.</para>
|
|
|
|
<para>Once a user set has been defined, its name may be placed in the USER
|
|
SET column of the /etc/shorewall/rules file.</para>
|
|
|
|
<important>
|
|
<para>When the name of a user set is given in the USER SET column, you
|
|
may not include a log level in the ACTION column; logging of such rules
|
|
is governed solely by the user set's definition in the
|
|
/etc/shorewall/userset file.</para>
|
|
</important>
|
|
|
|
<example>
|
|
<title>You want members of the <quote>admin</quote> group and
|
|
<quote>root</quote> to be able to use ssh on the firewall to connect to
|
|
local systems. You want to log all connections accepted for these users
|
|
using syslog at the <quote>info</quote> level.</title>
|
|
|
|
<para>/etc/shorewall/usersets</para>
|
|
|
|
<programlisting>#USERSET REJECT ACCEPT DROP
|
|
admins - info</programlisting>
|
|
|
|
<para>/etc/shorewall/users</para>
|
|
|
|
<programlisting>#USERSET USER GROUP
|
|
admins - admin
|
|
admins root</programlisting>
|
|
|
|
<para>/etc/shorewall/rules</para>
|
|
|
|
<programlisting>#ACTION SOURCE DESTINATION PROTO PORT SOURCE ORIGINAL RATE USER
|
|
# PORT(S) DESTINATION SET
|
|
|
|
ACCEPT $FW loc tcp 22 - - - admins</programlisting>
|
|
</example>
|
|
</section>
|
|
|
|
<section id="Rule">
|
|
<title>Restricting a rule to a particular user and/or group</title>
|
|
|
|
<para>In cases where you may want to restrict a rule to a particular user
|
|
and/or group, the USER SET column in the rules file may be specified as:</para>
|
|
|
|
<programlisting>[ <<emphasis>user name or number</emphasis>> ] : [ <<emphasis>group name or number</emphasis>> ]</programlisting>
|
|
|
|
<para>When a user and/or group name is given in the USER SET column, it is
|
|
OK to specify a log level in the ACTION column.</para>
|
|
|
|
<example>
|
|
<title>You want user <emphasis role="bold">mail</emphasis> to be able to
|
|
send email from the firewall to the local net zone</title>
|
|
|
|
<para>/etc/shorewall/rules (be sure to note the <quote>:</quote> in the
|
|
USER SET column entry).</para>
|
|
|
|
<programlisting>#ACTION SOURCE DESTINATION PROTO PORT SOURCE ORIGINAL RATE USER
|
|
# PORT(S) DESTINATION SET
|
|
|
|
ACCEPT $FW loc tcp 25 - - - mail:</programlisting>
|
|
</example>
|
|
</section>
|
|
</article> |