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-
- <h1 align="center">Apache suEXEC Support</h1>
-
- <ol>
- <li><big><strong>CONTENTS</strong></big></li>
-
- <li><a href="#what">What is suEXEC?</a></li>
-
- <li><a href="#before">Before we begin.</a></li>
-
- <li><a href="#model">suEXEC Security Model.</a></li>
-
- <li><a href="#install">Configuring & Installing
- suEXEC</a></li>
-
- <li><a href="#enable">Enabling & Disabling
- suEXEC</a></li>
-
- <li><a href="#usage">Using suEXEC</a></li>
-
- <li><a href="#debug">Debugging suEXEC</a></li>
-
- <li><a href="#jabberwock">Beware the Jabberwock: Warnings
- & Examples</a></li>
- </ol>
- <br />
- <br />
-
-
- <h3><a id="what" name="what">What is suEXEC?</a></h3>
-
- <p align="left">The <strong>suEXEC</strong> feature provides
+<html><head><META http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><!--
+ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+ This file is generated from xml source: DO NOT EDIT
+ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+ --><title>suEXEC Support - Apache HTTP Server</title><link href="./style/manual.css" type="text/css" rel="stylesheet"></head><body><blockquote><div align="center"><img src="./images/sub.gif" alt="[APACHE DOCUMENTATION]"><h3>Apache HTTP Server Version 2.0</h3></div><h1 align="center">suEXEC Support</h1>
+ <p>The <strong>suEXEC</strong> feature provides
Apache users the ability
to run <strong>CGI</strong> and <strong>SSI</strong> programs
under user IDs different from the user ID of the calling
web-server. Normally, when a CGI or SSI program executes, it
runs as the same user who is running the web server.</p>
- <p align="left">Used properly, this feature can reduce
+ <p>Used properly, this feature can reduce
considerably the security risks involved with allowing users to
develop and run private CGI or SSI programs. However, if suEXEC
is improperly configured, it can cause any number of problems
you aren't familiar with managing setuid root programs and the
security issues they present, we highly recommend that you not
consider using suEXEC.</p>
+ <ul><li><a href="#before">Before we begin</a></li><li><a href="#model">suEXEC Security Model</a></li><li><a href="#install">Configuring & Installing
+ suEXEC</a></li><li><a href="#enable">Enabling & Disabling
+ suEXEC</a></li><li><a href="#usage">Using suEXEC</a></li><li><a href="#debug">Debugging suEXEC</a></li><li><a href="#jabberwock">Beware the Jabberwock:
+ Warnings & Examples</a></li></ul><hr><h2><a name="before">Before we begin</a></h2>
- <p align="center"><strong><a href="suexec.html">BACK TO
- CONTENTS</a></strong></p>
-
- <h3><a id="before" name="before">Before we begin.</a></h3>
-
- <p align="left">Before jumping head-first into this document,
+ <p>Before jumping head-first into this document,
you should be aware of the assumptions made on the part of the
Apache Group and this document.</p>
- <p align="left">First, it is assumed that you are using a UNIX
+ <p>First, it is assumed that you are using a UNIX
derivate operating system that is capable of
<strong>setuid</strong> and <strong>setgid</strong> operations.
All command examples are given in this regard. Other platforms,
if they are capable of supporting suEXEC, may differ in their
configuration.</p>
- <p align="left">Second, it is assumed you are familiar with
+ <p>Second, it is assumed you are familiar with
some basic concepts of your computer's security and its
administration. This involves an understanding of
<strong>setuid/setgid</strong> operations and the various
effects they may have on your system and its level of
security.</p>
- <p align="left">Third, it is assumed that you are using an
+ <p>Third, it is assumed that you are using an
<strong>unmodified</strong> version of suEXEC code. All code
for suEXEC has been carefully scrutinized and tested by the
developers as well as numerous beta testers. Every precaution
particulars of security programming and are willing to share
your work with the Apache Group for consideration.</p>
- <p align="left">Fourth, and last, it has been the decision of
+ <p>Fourth, and last, it has been the decision of
the Apache Group to <strong>NOT</strong> make suEXEC part of
the default installation of Apache. To this end, suEXEC
configuration requires of the administrator careful attention
installation only to those who are careful and determined
enough to use it.</p>
- <p align="left">Still with us? Yes? Good. Let's move on!</p>
+ <p>Still with us? Yes? Good. Let's move on!</p>
+<h2><a name="model">suEXEC Security Model</a></h2>
- <p align="center"><strong><a href="suexec.html">BACK TO
- CONTENTS</a></strong></p>
-
- <h3><a id="model" name="model">suEXEC Security Model</a></h3>
-
- <p align="left">Before we begin configuring and installing
+ <p>Before we begin configuring and installing
suEXEC, we will first discuss the security model you are about
to implement. By doing so, you may better understand what
exactly is going on inside suEXEC and what precautions are
taken to ensure your system's security.</p>
- <p align="left"><strong>suEXEC</strong> is based on a setuid
+ <p><strong>suEXEC</strong> is based on a setuid
"wrapper" program that is called by the main Apache web server.
This wrapper is called when an HTTP request is made for a CGI
or SSI program that the administrator has designated to run as
program's name and the user and group IDs under which the
program is to execute.</p>
- <p align="left">The wrapper then employs the following process
+ <p>The wrapper then employs the following process
to determine success or failure -- if any one of these
conditions fail, the program logs the failure and exits with an
error, otherwise it will continue:</p>
</blockquote>
</li>
</ol>
- <br />
- <br />
-
- <p align="left">This is the standard operation of the the
+ <p>This is the standard operation of the the
suEXEC wrapper's security model. It is somewhat stringent and
can impose new limitations and guidelines for CGI/SSI design,
but it was developed carefully step-by-step with security in
mind.</p>
- <p align="left">For more information as to how this security
+ <p>For more information as to how this security
model can limit your possibilities in regards to server
configuration, as well as what security risks can be avoided
- with a proper suEXEC setup, see the <a
- href="#jabberwock">"Beware the Jabberwock"</a> section of this
+ with a proper suEXEC setup, see the <a href="#jabberwock">"Beware the Jabberwock"</a> section of this
document.</p>
+<h2><a name="install">Configuring & Installing
+ suEXEC</a></h2>
- <p align="center"><strong><a href="suexec.html">BACK TO
- CONTENTS</a></strong></p>
-
- <h3><a id="install" name="install">Configuring & Installing
- suEXEC</a></h3>
-
- <p align="left">Here's where we begin the fun.</p>
+ <p>Here's where we begin the fun.</p>
- <p align="left"><strong>suEXEC configuration
- options</strong><br />
+ <p><strong>suEXEC configuration
+ options</strong><br>
</p>
<dl>
work properly in cases where the UserDir directive points to
a location that is not the same as the user's home directory
as referenced in the passwd file. Default value is
- "public_html".<br />
+ "public_html".<br>
If you have virtual hosts with a different UserDir for each,
you will need to define them to all reside in one parent
directory; then name that parent directory here. <strong>If
executables. Default value is
"/usr/local/bin:/usr/bin:/bin".</dd>
</dl>
- <br />
- <br />
-
- <p align="left"><strong>Checking your suEXEC
- setup</strong><br />
+ <p><strong>Checking your suEXEC
+ setup</strong><br>
Before you compile and install the suEXEC wrapper you can
- check the configuration with the --layout option.<br />
+ check the configuration with the --layout option.<br>
Example output:</p>
-<pre>
- suEXEC setup:
- suexec binary: /usr/local/apache/sbin/suexec
- document root: /usr/local/apache/share/htdocs
- userdir suffix: public_html
- logfile: /usr/local/apache/var/log/suexec_log
- safe path: /usr/local/bin:/usr/bin:/bin
- caller ID: www
- minimum user ID: 100
- minimum group ID: 100
-</pre>
- <br />
- <br />
-
-
- <p align="left"><strong>Compiling and installing the suEXEC
- wrapper</strong><br />
+
+<blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code>
+ suEXEC setup:<br>
+ suexec binary: /usr/local/apache/sbin/suexec<br>
+ document root: /usr/local/apache/share/htdocs<br>
+ userdir suffix: public_html<br>
+ logfile: /usr/local/apache/var/log/suexec_log<br>
+ safe path: /usr/local/bin:/usr/bin:/bin<br>
+ caller ID: www<br>
+ minimum user ID: 100<br>
+ minimum group ID: 100<br>
+</code></td></tr></table></blockquote>
+
+ <p><strong>Compiling and installing the suEXEC
+ wrapper</strong><br>
If you have enabled the suEXEC feature with the
--enable-suexec option the suexec binary (together with Apache
itself) is automatically built if you execute the command
- "make".<br />
+ "make".<br>
After all components have been built you can execute the
command "make install" to install them. The binary image
"suexec" is installed in the directory defined by the --sbindir
option. Default location is
- "/usr/local/apache/sbin/suexec".<br />
+ "/usr/local/apache/sbin/suexec".<br>
Please note that you need <strong><em>root
privileges</em></strong> for the installation step. In order
for the wrapper to set the user ID, it must be installed as
owner <code><em>root</em></code> and must have the setuserid
execution bit set for file modes.</p>
- <p align="center"><strong><a href="suexec.html">BACK TO
- CONTENTS</a></strong></p>
-
- <h3><a id="enable" name="enable">Enabling & Disabling
- suEXEC</a></h3>
+<h2><a name="enable">Enabling & Disabling
+ suEXEC</a></h2>
- <p align="left">Upon startup of Apache, it looks for the file
+ <p>Upon startup of Apache, it looks for the file
"suexec" in the "sbin" directory (default is
"/usr/local/apache/sbin/suexec"). If Apache finds a properly
configured suEXEC wrapper, it will print the following message
to the error log:</p>
-<pre>
+<blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code>
[notice] suEXEC mechanism enabled (wrapper: <em>/path/to/suexec</em>)
-</pre>
- If you don't see this message at server startup, the server is
+</code></td></tr></table></blockquote>
+ <p>If you don't see this message at server startup, the server is
most likely not finding the wrapper program where it expects
- it, or the executable is not installed <em>setuid root</em>.
- <br />
- If you want to enable the suEXEC mechanism for the first time
+ it, or the executable is not installed <em>setuid root</em>.</p>
+
+ <p>If you want to enable the suEXEC mechanism for the first time
and an Apache server is already running you must kill and
restart Apache. Restarting it with a simple HUP or USR1 signal
- will not be enough. <br />
- If you want to disable suEXEC you should kill and restart
- Apache after you have removed the "suexec" file. <br />
- <br />
-
-
- <p align="center"><strong><a href="suexec.html">BACK TO
- CONTENTS</a></strong></p>
-
- <h3><a id="usage" name="usage">Using suEXEC</a></h3>
-
- <p align="left"><strong>Virtual Hosts:</strong><br />
- One way to use the suEXEC wrapper is through the <a
- href="mod/mod_suexec.html#suexecusergroup">SuexecUserGroup</a>
- directive in <a
- href="mod/core.html#virtualhost">VirtualHost</a> definitions.
- By setting this directive to values different from the main
- server user ID, all requests for CGI resources will be executed
- as the <em>User</em> and <em>Group</em> defined for that
- <code><VirtualHost></code>. If this directive is not
- specified for a
- <code><VirtualHost></code> then the main server userid is
- assumed.</p>
-
- <p><strong>User directories:</strong><br />
+ will not be enough. </p>
+ <p>If you want to disable suEXEC you should kill and restart
+ Apache after you have removed the "suexec" file. </p>
+<h2><a name="usage">Using suEXEC</a></h2>
+
+ <p><strong>Virtual Hosts:</strong><br> One way to use the suEXEC
+ wrapper is through the <a href="./mod/mod_suexec.html#suexecusergroup" class="directive"><code class="directive">SuexecUserGroup</code></a> directive in
+ <a href="./mod/core.html#virtualhost" class="directive"><code class="directive">VirtualHost</code></a> definitions. By
+ setting this directive to values different from the main server
+ user ID, all requests for CGI resources will be executed as the
+ <em>User</em> and <em>Group</em> defined for that <a href="./mod/core.html#virtualhost" class="directive"><code class="directive"><VirtualHost></code></a>. If this
+ directive is not specified for a <a href="./mod/core.html#virtualhost" class="directive"><code class="directive"><VirtualHost></code></a> then the main server userid
+ is assumed.</p>
+
+ <p><strong>User directories:</strong><br>
The suEXEC wrapper can also be used to execute CGI programs as
the user to which the request is being directed. This is
accomplished by using the "<strong><code>~</code></strong>"
execution to be enabled for the user and that the script must
meet the scrutiny of the <a href="#model">security checks</a>
above.</p>
+<h2><a name="debug">Debugging suEXEC</a></h2>
- <p align="center"><strong><a href="suexec.html">BACK TO
- CONTENTS</a></strong></p>
-
- <h3><a id="debug" name="debug">Debugging suEXEC</a></h3>
-
- <p align="left">The suEXEC wrapper will write log information
+ <p>The suEXEC wrapper will write log information
to the file defined with the --with-suexec-logfile option as
indicated above. If you feel you have configured and installed
the wrapper properly, have a look at this log and the error_log
for the server to see where you may have gone astray.</p>
- <p align="center"><strong><a href="suexec.html">BACK TO
- CONTENTS</a></strong></p>
-
- <h3><a id="jabberwock" name="jabberwock">Beware the Jabberwock:
- Warnings & Examples</a></h3>
+<h2><a name="jabberwock">Beware the Jabberwock:
+ Warnings & Examples</a></h2>
- <p align="left"><strong>NOTE!</strong> This section may not be
+ <p><strong>NOTE!</strong> This section may not be
complete. For the latest revision of this section of the
- documentation, see the Apache Group's <a
- href="http://www.apache.org/docs/suexec.html">Online
+ documentation, see the Apache Group's <a href="http://www.apache.org/docs-2.0/suexec.html">Online
Documentation</a> version.</p>
- <p align="left">There are a few points of interest regarding
+ <p>There are a few points of interest regarding
the wrapper that can cause limitations on server setup. Please
review these before submitting any "bugs" regarding suEXEC.</p>
</li>
</ul>
- <p align="center"><strong><a href="suexec.html">BACK TO
- CONTENTS</a></strong></p>
- <!--#include virtual="footer.html" -->
- </body>
-</html>
-
+<hr></blockquote><h3 align="center">Apache HTTP Server Version 2.0</h3><a href="./"><img src="./images/index.gif" alt="Index"></a><a href="./"><img src="./images/home.gif" alt="Home"></a></body></html>
\ No newline at end of file
--- /dev/null
+<?xml version="1.0" encoding="UTF-8" ?>
+<!DOCTYPE manualpage SYSTEM "./style/manualpage.dtd">
+<?xml-stylesheet type="text/xsl" href="./style/manual.en.xsl"?>
+
+<manualpage>
+ <relativepath href="."/>
+
+ <title>suEXEC Support</title>
+
+ <summary>
+ <p>The <strong>suEXEC</strong> feature provides
+ Apache users the ability
+ to run <strong>CGI</strong> and <strong>SSI</strong> programs
+ under user IDs different from the user ID of the calling
+ web-server. Normally, when a CGI or SSI program executes, it
+ runs as the same user who is running the web server.</p>
+
+ <p>Used properly, this feature can reduce
+ considerably the security risks involved with allowing users to
+ develop and run private CGI or SSI programs. However, if suEXEC
+ is improperly configured, it can cause any number of problems
+ and possibly create new holes in your computer's security. If
+ you aren't familiar with managing setuid root programs and the
+ security issues they present, we highly recommend that you not
+ consider using suEXEC.</p>
+ </summary>
+
+<section id="before"><title>Before we begin</title>
+
+ <p>Before jumping head-first into this document,
+ you should be aware of the assumptions made on the part of the
+ Apache Group and this document.</p>
+
+ <p>First, it is assumed that you are using a UNIX
+ derivate operating system that is capable of
+ <strong>setuid</strong> and <strong>setgid</strong> operations.
+ All command examples are given in this regard. Other platforms,
+ if they are capable of supporting suEXEC, may differ in their
+ configuration.</p>
+
+ <p>Second, it is assumed you are familiar with
+ some basic concepts of your computer's security and its
+ administration. This involves an understanding of
+ <strong>setuid/setgid</strong> operations and the various
+ effects they may have on your system and its level of
+ security.</p>
+
+ <p>Third, it is assumed that you are using an
+ <strong>unmodified</strong> version of suEXEC code. All code
+ for suEXEC has been carefully scrutinized and tested by the
+ developers as well as numerous beta testers. Every precaution
+ has been taken to ensure a simple yet solidly safe base of
+ code. Altering this code can cause unexpected problems and new
+ security risks. It is <strong>highly</strong> recommended you
+ not alter the suEXEC code unless you are well versed in the
+ particulars of security programming and are willing to share
+ your work with the Apache Group for consideration.</p>
+
+ <p>Fourth, and last, it has been the decision of
+ the Apache Group to <strong>NOT</strong> make suEXEC part of
+ the default installation of Apache. To this end, suEXEC
+ configuration requires of the administrator careful attention
+ to details. After due consideration has been given to the
+ various settings for suEXEC, the administrator may install
+ suEXEC through normal installation methods. The values for
+ these settings need to be carefully determined and specified by
+ the administrator to properly maintain system security during
+ the use of suEXEC functionality. It is through this detailed
+ process that the Apache Group hopes to limit suEXEC
+ installation only to those who are careful and determined
+ enough to use it.</p>
+
+ <p>Still with us? Yes? Good. Let's move on!</p>
+</section>
+
+<section id="model"><title>suEXEC Security Model</title>
+
+ <p>Before we begin configuring and installing
+ suEXEC, we will first discuss the security model you are about
+ to implement. By doing so, you may better understand what
+ exactly is going on inside suEXEC and what precautions are
+ taken to ensure your system's security.</p>
+
+ <p><strong>suEXEC</strong> is based on a setuid
+ "wrapper" program that is called by the main Apache web server.
+ This wrapper is called when an HTTP request is made for a CGI
+ or SSI program that the administrator has designated to run as
+ a userid other than that of the main server. When such a
+ request is made, Apache provides the suEXEC wrapper with the
+ program's name and the user and group IDs under which the
+ program is to execute.</p>
+
+ <p>The wrapper then employs the following process
+ to determine success or failure -- if any one of these
+ conditions fail, the program logs the failure and exits with an
+ error, otherwise it will continue:</p>
+
+ <ol>
+ <li>
+ <strong>Was the wrapper called with the proper number of
+ arguments?</strong>
+
+ <blockquote>
+ The wrapper will only execute if it is given the proper
+ number of arguments. The proper argument format is known
+ to the Apache web server. If the wrapper is not receiving
+ the proper number of arguments, it is either being
+ hacked, or there is something wrong with the suEXEC
+ portion of your Apache binary.
+ </blockquote>
+ </li>
+
+ <li>
+ <strong>Is the user executing this wrapper a valid user of
+ this system?</strong>
+
+ <blockquote>
+ This is to ensure that the user executing the wrapper is
+ truly a user of the system.
+ </blockquote>
+ </li>
+
+ <li>
+ <strong>Is this valid user allowed to run the
+ wrapper?</strong>
+
+ <blockquote>
+ Is this user the user allowed to run this wrapper? Only
+ one user (the Apache user) is allowed to execute this
+ program.
+ </blockquote>
+ </li>
+
+ <li>
+ <strong>Does the target program have an unsafe hierarchical
+ reference?</strong>
+
+ <blockquote>
+ Does the target program contain a leading '/' or have a
+ '..' backreference? These are not allowed; the target
+ program must reside within the Apache webspace.
+ </blockquote>
+ </li>
+
+ <li>
+ <strong>Is the target user name valid?</strong>
+
+ <blockquote>
+ Does the target user exist?
+ </blockquote>
+ </li>
+
+ <li>
+ <strong>Is the target group name valid?</strong>
+
+ <blockquote>
+ Does the target group exist?
+ </blockquote>
+ </li>
+
+ <li>
+ <strong>Is the target user <em>NOT</em> superuser?</strong>
+
+
+ <blockquote>
+ Presently, suEXEC does not allow 'root' to execute
+ CGI/SSI programs.
+ </blockquote>
+ </li>
+
+ <li>
+ <strong>Is the target userid <em>ABOVE</em> the minimum ID
+ number?</strong>
+
+ <blockquote>
+ The minimum user ID number is specified during
+ configuration. This allows you to set the lowest possible
+ userid that will be allowed to execute CGI/SSI programs.
+ This is useful to block out "system" accounts.
+ </blockquote>
+ </li>
+
+ <li>
+ <strong>Is the target group <em>NOT</em> the superuser
+ group?</strong>
+
+ <blockquote>
+ Presently, suEXEC does not allow the 'root' group to
+ execute CGI/SSI programs.
+ </blockquote>
+ </li>
+
+ <li>
+ <strong>Is the target groupid <em>ABOVE</em> the minimum ID
+ number?</strong>
+
+ <blockquote>
+ The minimum group ID number is specified during
+ configuration. This allows you to set the lowest possible
+ groupid that will be allowed to execute CGI/SSI programs.
+ This is useful to block out "system" groups.
+ </blockquote>
+ </li>
+
+ <li>
+ <strong>Can the wrapper successfully become the target user
+ and group?</strong>
+
+ <blockquote>
+ Here is where the program becomes the target user and
+ group via setuid and setgid calls. The group access list
+ is also initialized with all of the groups of which the
+ user is a member.
+ </blockquote>
+ </li>
+
+ <li>
+ <strong>Does the directory in which the program resides
+ exist?</strong>
+
+ <blockquote>
+ If it doesn't exist, it can't very well contain files.
+ </blockquote>
+ </li>
+
+ <li>
+ <strong>Is the directory within the Apache
+ webspace?</strong>
+
+ <blockquote>
+ If the request is for a regular portion of the server, is
+ the requested directory within the server's document
+ root? If the request is for a UserDir, is the requested
+ directory within the user's document root?
+ </blockquote>
+ </li>
+
+ <li>
+ <strong>Is the directory <em>NOT</em> writable by anyone
+ else?</strong>
+
+ <blockquote>
+ We don't want to open up the directory to others; only
+ the owner user may be able to alter this directories
+ contents.
+ </blockquote>
+ </li>
+
+ <li>
+ <strong>Does the target program exist?</strong>
+
+ <blockquote>
+ If it doesn't exists, it can't very well be executed.
+ </blockquote>
+ </li>
+
+ <li>
+ <strong>Is the target program <em>NOT</em> writable by
+ anyone else?</strong>
+
+ <blockquote>
+ We don't want to give anyone other than the owner the
+ ability to change the program.
+ </blockquote>
+ </li>
+
+ <li>
+ <strong>Is the target program <em>NOT</em> setuid or
+ setgid?</strong>
+
+ <blockquote>
+ We do not want to execute programs that will then change
+ our UID/GID again.
+ </blockquote>
+ </li>
+
+ <li>
+ <strong>Is the target user/group the same as the program's
+ user/group?</strong>
+
+ <blockquote>
+ Is the user the owner of the file?
+ </blockquote>
+ </li>
+
+ <li>
+ <strong>Can we successfully clean the process environment
+ to ensure safe operations?</strong>
+
+ <blockquote>
+ suEXEC cleans the process' environment by establishing a
+ safe execution PATH (defined during configuration), as
+ well as only passing through those variables whose names
+ are listed in the safe environment list (also created
+ during configuration).
+ </blockquote>
+ </li>
+
+ <li>
+ <strong>Can we successfully become the target program and
+ execute?</strong>
+
+ <blockquote>
+ Here is where suEXEC ends and the target program begins.
+ </blockquote>
+ </li>
+ </ol>
+
+ <p>This is the standard operation of the the
+ suEXEC wrapper's security model. It is somewhat stringent and
+ can impose new limitations and guidelines for CGI/SSI design,
+ but it was developed carefully step-by-step with security in
+ mind.</p>
+
+ <p>For more information as to how this security
+ model can limit your possibilities in regards to server
+ configuration, as well as what security risks can be avoided
+ with a proper suEXEC setup, see the <a
+ href="#jabberwock">"Beware the Jabberwock"</a> section of this
+ document.</p>
+</section>
+
+<section id="install"><title>Configuring & Installing
+ suEXEC</title>
+
+ <p>Here's where we begin the fun.</p>
+
+ <p><strong>suEXEC configuration
+ options</strong><br />
+ </p>
+
+ <dl>
+ <dt><code>--enable-suexec</code></dt>
+
+ <dd>This option enables the suEXEC feature which is never
+ installed or activated by default. At least one
+ --with-suexec-xxxxx option has to be provided together with the
+ --enable-suexec option to let APACI accept your request for
+ using the suEXEC feature.</dd>
+
+ <dt><code>--with-suexec-bin=<em>PATH</em></code></dt>
+
+ <dd>The path to the suexec binary must be hard-coded in
+ the server for security reasons. Use this option to override
+ the default path. <em>e.g.</em>
+ <code>--with-suexec-bin=/usr/sbin/suexec</code></dd>
+
+ <dt><code>--with-suexec-caller=<em>UID</em></code></dt>
+
+ <dd>The <a href="mod/mpm_common.html#user">username</a> under which
+ Apache normally runs. This is the only user allowed to
+ execute this program.</dd>
+
+ <dt><code>--with-suexec-userdir=<em>DIR</em></code></dt>
+
+ <dd>Define to be the subdirectory under users' home
+ directories where suEXEC access should be allowed. All
+ executables under this directory will be executable by suEXEC
+ as the user so they should be "safe" programs. If you are
+ using a "simple" UserDir directive (ie. one without a "*" in
+ it) this should be set to the same value. suEXEC will not
+ work properly in cases where the UserDir directive points to
+ a location that is not the same as the user's home directory
+ as referenced in the passwd file. Default value is
+ "public_html".<br />
+ If you have virtual hosts with a different UserDir for each,
+ you will need to define them to all reside in one parent
+ directory; then name that parent directory here. <strong>If
+ this is not defined properly, "~userdir" cgi requests will
+ not work!</strong></dd>
+
+ <dt><code>--with-suexec-docroot=<em>DIR</em></code></dt>
+
+ <dd>Define as the DocumentRoot set for Apache. This will be
+ the only hierarchy (aside from UserDirs) that can be used for
+ suEXEC behavior. The default directory is the --datadir value
+ with the suffix "/htdocs", <em>e.g.</em> if you configure
+ with "<code>--datadir=/home/apache</code>" the directory
+ "/home/apache/htdocs" is used as document root for the suEXEC
+ wrapper.</dd>
+
+ <dt><code>--with-suexec-uidmin=<em>UID</em></code></dt>
+
+ <dd>Define this as the lowest UID allowed to be a target user
+ for suEXEC. For most systems, 500 or 100 is common. Default
+ value is 100.</dd>
+
+ <dt><code>--with-suexec-gidmin=<em>GID</em></code></dt>
+
+ <dd>Define this as the lowest GID allowed to be a target
+ group for suEXEC. For most systems, 100 is common and
+ therefore used as default value.</dd>
+
+ <dt><code>--with-suexec-logfile=<em>FILE</em></code></dt>
+
+ <dd>This defines the filename to which all suEXEC
+ transactions and errors are logged (useful for auditing and
+ debugging purposes). By default the logfile is named
+ "suexec_log" and located in your standard logfile directory
+ (--logfiledir).</dd>
+
+ <dt><code>--with-suexec-safepath=<em>PATH</em></code></dt>
+
+ <dd>Define a safe PATH environment to pass to CGI
+ executables. Default value is
+ "/usr/local/bin:/usr/bin:/bin".</dd>
+ </dl>
+
+ <p><strong>Checking your suEXEC
+ setup</strong><br />
+ Before you compile and install the suEXEC wrapper you can
+ check the configuration with the --layout option.<br />
+ Example output:</p>
+
+<example>
+ suEXEC setup:<br />
+ suexec binary: /usr/local/apache/sbin/suexec<br />
+ document root: /usr/local/apache/share/htdocs<br />
+ userdir suffix: public_html<br />
+ logfile: /usr/local/apache/var/log/suexec_log<br />
+ safe path: /usr/local/bin:/usr/bin:/bin<br />
+ caller ID: www<br />
+ minimum user ID: 100<br />
+ minimum group ID: 100<br />
+</example>
+
+ <p><strong>Compiling and installing the suEXEC
+ wrapper</strong><br />
+ If you have enabled the suEXEC feature with the
+ --enable-suexec option the suexec binary (together with Apache
+ itself) is automatically built if you execute the command
+ "make".<br />
+ After all components have been built you can execute the
+ command "make install" to install them. The binary image
+ "suexec" is installed in the directory defined by the --sbindir
+ option. Default location is
+ "/usr/local/apache/sbin/suexec".<br />
+ Please note that you need <strong><em>root
+ privileges</em></strong> for the installation step. In order
+ for the wrapper to set the user ID, it must be installed as
+ owner <code><em>root</em></code> and must have the setuserid
+ execution bit set for file modes.</p>
+
+</section>
+
+<section id="enable"><title>Enabling & Disabling
+ suEXEC</title>
+
+ <p>Upon startup of Apache, it looks for the file
+ "suexec" in the "sbin" directory (default is
+ "/usr/local/apache/sbin/suexec"). If Apache finds a properly
+ configured suEXEC wrapper, it will print the following message
+ to the error log:</p>
+<example>
+ [notice] suEXEC mechanism enabled (wrapper: <em>/path/to/suexec</em>)
+</example>
+ <p>If you don't see this message at server startup, the server is
+ most likely not finding the wrapper program where it expects
+ it, or the executable is not installed <em>setuid root</em>.</p>
+
+ <p>If you want to enable the suEXEC mechanism for the first time
+ and an Apache server is already running you must kill and
+ restart Apache. Restarting it with a simple HUP or USR1 signal
+ will not be enough. </p>
+ <p>If you want to disable suEXEC you should kill and restart
+ Apache after you have removed the "suexec" file. </p>
+</section>
+
+<section id="usage"><title>Using suEXEC</title>
+
+ <p><strong>Virtual Hosts:</strong><br /> One way to use the suEXEC
+ wrapper is through the <directive
+ module="mod_suexec">SuexecUserGroup</directive> directive in
+ <directive module="core">VirtualHost</directive> definitions. By
+ setting this directive to values different from the main server
+ user ID, all requests for CGI resources will be executed as the
+ <em>User</em> and <em>Group</em> defined for that <directive
+ module="core" type="section">VirtualHost</directive>. If this
+ directive is not specified for a <directive module="core"
+ type="section">VirtualHost</directive> then the main server userid
+ is assumed.</p>
+
+ <p><strong>User directories:</strong><br />
+ The suEXEC wrapper can also be used to execute CGI programs as
+ the user to which the request is being directed. This is
+ accomplished by using the "<strong><code>~</code></strong>"
+ character prefixing the user ID for whom execution is desired.
+ The only requirement needed for this feature to work is for CGI
+ execution to be enabled for the user and that the script must
+ meet the scrutiny of the <a href="#model">security checks</a>
+ above.</p>
+</section>
+
+<section id="debug"><title>Debugging suEXEC</title>
+
+ <p>The suEXEC wrapper will write log information
+ to the file defined with the --with-suexec-logfile option as
+ indicated above. If you feel you have configured and installed
+ the wrapper properly, have a look at this log and the error_log
+ for the server to see where you may have gone astray.</p>
+
+</section>
+
+<section id="jabberwock"><title>Beware the Jabberwock:
+ Warnings & Examples</title>
+
+ <p><strong>NOTE!</strong> This section may not be
+ complete. For the latest revision of this section of the
+ documentation, see the Apache Group's <a
+ href="http://www.apache.org/docs-2.0/suexec.html">Online
+ Documentation</a> version.</p>
+
+ <p>There are a few points of interest regarding
+ the wrapper that can cause limitations on server setup. Please
+ review these before submitting any "bugs" regarding suEXEC.</p>
+
+ <ul>
+ <li><strong>suEXEC Points Of Interest</strong></li>
+
+ <li>
+ Hierarchy limitations
+
+ <blockquote>
+ For security and efficiency reasons, all suexec requests
+ must remain within either a top-level document root for
+ virtual host requests, or one top-level personal document
+ root for userdir requests. For example, if you have four
+ VirtualHosts configured, you would need to structure all
+ of your VHosts' document roots off of one main Apache
+ document hierarchy to take advantage of suEXEC for
+ VirtualHosts. (Example forthcoming.)
+ </blockquote>
+ </li>
+
+ <li>
+ suEXEC's PATH environment variable
+
+ <blockquote>
+ This can be a dangerous thing to change. Make certain
+ every path you include in this define is a
+ <strong>trusted</strong> directory. You don't want to
+ open people up to having someone from across the world
+ running a trojan horse on them.
+ </blockquote>
+ </li>
+
+ <li>
+ Altering the suEXEC code
+
+ <blockquote>
+ Again, this can cause <strong>Big Trouble</strong> if you
+ try this without knowing what you are doing. Stay away
+ from it if at all possible.
+ </blockquote>
+ </li>
+ </ul>
+
+</section>
+
+</manualpage>
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