-<html><head>
-<title>Apache SetUserID Support</title>
-</head><body>
-
-<!--#include virtual="header.html" -->
-<h1>Apache SetUserID Support</h1>
-
-<hr>
-
-<h2>What is suEXEC?</h2>
-The <b>suEXEC</b> feature, introduced in Apache 1.2 provides the ability to
-run <b>CGI</b> programs under user ids different from the user id of the
-calling webserver. Used properly, this feature can reduce considerably the
-insecurity of allowing users to run CGI programs. At the same time, improperly
-configured, this facility can crash your computer, burn your house down and
-steal all the money from your retirement fund. <b>:-)</b> If you aren't
-familar with managing setuid root programs and the security issues they
-present, we highly recommend that you not consider using this feature.<p>
-
-<h2>Enabling suEXEC Support</h2>
-Having said all that, enabling this feature is purposefully difficult with
-the intent that it will only be installed by users determined to use it and
-is not part of the normal install/compile process.<p>
-
-<ul>
-<h3>Configuring the suEXEC wrapper</h3>
-From the toplevel of the Apache source tree, type: <b><code>cd support [ENTER]</code></b><p>
-Edit the <code>suexec.h</code> file and change the following macros to match your
-local Apache installation.<p>
-<i>From support/suexec.h</i>
-<code>
-<pre>
-/*
- * HTTPD_USER -- Define as the username under which Apache normally
- * runs. This is the only user allowed to execute
- * this program.
- */
-#define HTTPD_USER "www"
-
-/*
- * LOG_EXEC -- Define this as a filename if you want all suEXEC
- * transactions and errors logged for auditing and
- * debugging purposes.
- */
-#define LOG_EXEC "/usr/local/etc/httpd/logs/cgi.log"
-
-/*
- * DOC_ROOT -- Define as the DocuemntRoot set for Apache. This
- * will be the only hierarchy (aside from UserDirs)
- * that can be used for suEXEC behaviour.
- */
-#define DOC_ROOT "/usr/local/etc/httpd/htdocs"
-
-/*
- * NNAME -- Define this as the name for the nobody account
- * on your operating system. Most systems will just
- * need the default 'nobody'.
- */
-#define NNAME "nobody"
-
-/* NGID -- Define this as the *number* for the nogroup group
- * on your operating system. Most systems will have
- * a -1 or -2. Others might have something above
- * 65000.
- */
-#define NGID -1
-</pre>
-</code>
-
-<h3>Compiling the suEXEC wrapper</h3>
-At the shell command prompt, type: <b><code>cc suexec.c -o suexec [ENTER]</code></b>.<p>
-This should create the <b><em>suexec</em></b> wrapper executable.
-
-<h3>Compiling Apache for suEXEC support</h3>
-By default, Apache is compiled to look for the suEXEC wrapper in the following
-location.<p>
-<i>From src/httpd.h</i>
-<code>
-<pre>
-/* The path to the suEXEC wrapper */
-#ifndef SUEXEC_BIN
-#define SUEXEC_BIN "/usr/local/etc/httpd/sbin/suexec"
-#endif
-</pre>
-</code>
-<p>
-If your installation requires location of the wrapper program in a different
-directory, edit src/httpd.h and recompile your Apache server. See <a href="install.html">Compiling and Installing Apache</a> for more info on this process.<p>
-
-<h3>Installing the suEXEC wrapper</h3>
-Copy the <b><em>suexec</em></b> executable created in the exercise above to the defined
-location for <b>SUEXEC_BIN</b>.<p>
-In order for the wrapper to set the user id for execution requests it must me installed
-as owner <b><em>root</em></b> and must have the setuserid execution bit set for file modes.
-If you are not running a <b><em>root</em></b> user shell, do so now and execute the following
-commands.<p>
-
-<b><code>chown root /usr/local/etc/httpd/sbin/suexec [ENTER]</code></b><p>
-<b><code>chmod 4711 /usr/local/etc/httpd/sbin/suexec [ENTER]</code></b><p>
-
-<i>Change the path to the suEXEC wrapper to match your system installation.</i>
-</ul>
-
-<a name="model"></a>
-<h2>Security Model of suEXEC</h2>
-The <b>suEXEC</b> wrapper supplied with Apache performs the following security
-checks before it will execute any program passed to it for execution.
-<ol>
-<li>User executing the wrapper <b>must be a valid user on this system</b>.
-<li>User executing the wrapper <b>must be the compiled in HTTPD_USER</b>.
-<li>The command that the request wishes to execute <b>must not contain a /</b>.
-<li>The command being executed <b>must reside under the compiled in DOC_ROOT</b>.
-<li>The current working directory <b>must be a directory</b>.
-<li>The current working directory <b>must not be writable by <em>group</em> or <em>other</em></b>.
-<li>The command being executed <b>cannot be a symbolic link</b>.
-<li>The command being executed <b>cannot be writeable by <em>group</em> or <em>other</em></b>.
-<li>The command being executed <b>cannot be a <em>setuid</em> or <em>setgid</em> program</b>.
-<li>The target UID and GID <b>must be a valid user and group on this system</b>.
-<li>The target UID and GID to execute as, <b>must match the UID and GID of the directory</b>.
-<li>The target execution UID and GID <b>must not be the privledged ID 0</b>.
-<li>Group access list is set to NOGROUP and the command is executed.
-</ol>
-If any of these issues are too restrictive, or do not seem restrictive enough, you are
-welcome to install your own version of the wrapper. We've given you the rope, now go
-have fun with it. <b>:-)</b>
-
-<h2>Using suEXEC</h2>
-After properly installing the <b>suexec</b> wrapper executable, you must kill and restart
-the Apache server. A simple <code><b>kill -1 `cat httpd.pid`</b></code> will not be enough.
-Upon startup of the webserver, if Apache finds a properly configured <b>suexec</b> wrapper,
-it will print the following message to the console.<p>
-
-<code>Configuring Apache for use with suexec wrapper.</code><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 <b><em>setuid root</em></b>. Check your installation and try again.<p>
-
-One way to use <b>suEXEC</b> is through the <a href="mod/core.html#user"><b>User</b></a> and <a href="mod/core.html#group"><b>Group</b></a> directives in <a href="mod_core.html#virtualhost"><b>VirtualHost</b></a> definitions. By setting these directives to values
-different from the main server user id, all requests for CGI resources will be executed as
-the <b>User</b> and <b>Group</b> defined for that <b><VirtualHost></b>. If only one or
-neither of these directives are specified for a <b><VirtualHost></b> then the main
-server userid is assumed.<p>
-
-<b>suEXEC</b> can also be used to to execute CGI programs as the user to which the request
-is being directed. This is accomplished by using the <b>~</b> 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.
-
-<h2>Debugging suEXEC</h2>
-The suEXEC wrapper will write log information to the location defined in the <code>suexec.h</code> 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.
-<!--#include virtual="footer.html" -->
-
-</BODY>
-</HTML>
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head><!--
+ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+ This file is generated from xml source: DO NOT EDIT
+ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+ -->
+<title>suEXEC Support - Apache HTTP Server</title>
+<link href="./style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" />
+<link href="./style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" />
+<link href="./style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" /><link rel="stylesheet" type="text/css" href="./style/css/prettify.css" />
+<script src="./style/scripts/prettify.js" type="text/javascript">
+</script>
+<link href="./images/favicon.ico" rel="shortcut icon" /></head>
+<body id="manual-page"><div id="page-header">
+<p class="menu"><a href="./mod/">Modules</a> | <a href="./mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="./glossary.html">Glossary</a> | <a href="./sitemap.html">Sitemap</a></p>
+<p class="apache">Apache HTTP Server Version 2.5</p>
+<img alt="" src="./images/feather.gif" /></div>
+<div class="up"><a href="./"><img title="<-" alt="<-" src="./images/left.gif" /></a></div>
+<div id="path">
+<a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="./">Version 2.5</a></div><div id="page-content"><div id="preamble"><h1>suEXEC Support</h1>
+<div class="toplang">
+<p><span>Available Languages: </span><a href="./en/suexec.html" title="English"> en </a> |
+<a href="./fr/suexec.html" hreflang="fr" rel="alternate" title="Français"> fr </a> |
+<a href="./ja/suexec.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
+<a href="./ko/suexec.html" hreflang="ko" rel="alternate" title="Korean"> ko </a> |
+<a href="./tr/suexec.html" hreflang="tr" rel="alternate" title="Türkçe"> tr </a></p>
+</div>
+
+ <p>The <strong>suEXEC</strong> feature provides users of the Apache
+ HTTP Server 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 <em>setuid root</em> programs
+ and the security issues they present, we highly recommend that
+ you not consider using suEXEC.</p>
+ </div>
+<div id="quickview"><ul id="toc"><li><img alt="" src="./images/down.gif" /> <a href="#before">Before we begin</a></li>
+<li><img alt="" src="./images/down.gif" /> <a href="#model">suEXEC Security Model</a></li>
+<li><img alt="" src="./images/down.gif" /> <a href="#install">Configuring & Installing
+ suEXEC</a></li>
+<li><img alt="" src="./images/down.gif" /> <a href="#enable">Enabling & Disabling
+ suEXEC</a></li>
+<li><img alt="" src="./images/down.gif" /> <a href="#usage">Using suEXEC</a></li>
+<li><img alt="" src="./images/down.gif" /> <a href="#debug">Debugging suEXEC</a></li>
+<li><img alt="" src="./images/down.gif" /> <a href="#jabberwock">Beware the Jabberwock:
+ Warnings & Examples</a></li>
+</ul><ul class="seealso"><li><a href="#comments_section">Comments</a></li></ul></div>
+<div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
+<div class="section">
+<h2><a name="before" id="before">Before we begin</a></h2>
+
+ <p>Before jumping head-first into this document,
+ you should be aware that certain assumptions are made about you and
+ the environment in which you will be using suexec.</p>
+
+ <p>First, it is assumed that you are using a UNIX
+ derivative 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 HTTP Server development team for consideration.</p>
+
+ <p>Fourth, and last, it has been the decision of
+ the Apache HTTP Server development team to <strong>NOT</strong> make suEXEC part of
+ the default installation of Apache httpd. 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 we hope 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>
+</div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
+<div class="section">
+<h2><a name="model" id="model">suEXEC Security Model</a></h2>
+
+ <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 HTTP 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 httpd 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>Is the user executing this wrapper a valid user of
+ this system?</strong>
+
+ <p class="indent">
+ This is to ensure that the user executing the wrapper is
+ truly a user of the system.
+ </p>
+ </li>
+
+ <li>
+ <strong>Was the wrapper called with the proper number of
+ arguments?</strong>
+
+ <p class="indent">
+ The wrapper will only execute if it is given the proper
+ number of arguments. The proper argument format is known
+ to the Apache HTTP 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 httpd binary.
+ </p>
+ </li>
+
+ <li>
+ <strong>Is this valid user allowed to run the
+ wrapper?</strong>
+
+ <p class="indent">
+ Is this user the user allowed to run this wrapper? Only
+ one user (the Apache user) is allowed to execute this
+ program.
+ </p>
+ </li>
+
+ <li>
+ <strong>Does the target CGI or SSI program have an unsafe
+ hierarchical reference?</strong>
+
+ <p class="indent">
+ Does the target CGI or SSI program's path contain a leading
+ '/' or have a '..' backreference? These are not allowed; the
+ target CGI/SSI program must reside within suEXEC's document
+ root (see <code>--with-suexec-docroot=<em>DIR</em></code>
+ below).
+ </p>
+ </li>
+
+ <li>
+ <strong>Is the target user name valid?</strong>
+
+ <p class="indent">
+ Does the target user exist?
+ </p>
+ </li>
+
+ <li>
+ <strong>Is the target group name valid?</strong>
+
+ <p class="indent">
+ Does the target group exist?
+ </p>
+ </li>
+
+ <li>
+ <strong>Is the target user <em>NOT</em> superuser?</strong>
+
+
+ <p class="indent">
+ suEXEC does not allow <code><em>root</em></code>
+ to execute CGI/SSI programs.
+ </p>
+ </li>
+
+ <li>
+ <strong>Is the target userid <em>ABOVE</em> the minimum ID
+ number?</strong>
+
+ <p class="indent">
+ 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.
+ </p>
+ </li>
+
+ <li>
+ <strong>Is the target group <em>NOT</em> the superuser
+ group?</strong>
+
+ <p class="indent">
+ Presently, suEXEC does not allow the <code><em>root</em></code>
+ group to execute CGI/SSI programs.
+ </p>
+ </li>
+
+ <li>
+ <strong>Is the target groupid <em>ABOVE</em> the minimum ID
+ number?</strong>
+
+ <p class="indent">
+ 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.
+ </p>
+ </li>
+
+ <li>
+ <strong>Can the wrapper successfully become the target user
+ and group?</strong>
+
+ <p class="indent">
+ 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.
+ </p>
+ </li>
+
+ <li>
+ <strong>Can we change directory to the one in which the target
+ CGI/SSI program resides?</strong>
+
+ <p class="indent">
+ If it doesn't exist, it can't very well contain files. If we
+ can't change directory to it, it might as well not exist.
+ </p>
+ </li>
+
+ <li>
+ <strong>Is the directory within the httpd webspace?</strong>
+
+ <p class="indent">
+ If the request is for a regular portion of the server, is
+ the requested directory within suEXEC's document root? If
+ the request is for a <code class="directive"><a href="./mod/mod_userdir.html#userdir">UserDir</a></code>, is the requested directory
+ within the directory configured as suEXEC's userdir (see
+ <a href="#install">suEXEC's configuration options</a>)?
+ </p>
+ </li>
+
+ <li>
+ <strong>Is the directory <em>NOT</em> writable by anyone
+ else?</strong>
+
+ <p class="indent">
+ We don't want to open up the directory to others; only
+ the owner user may be able to alter this directories
+ contents.
+ </p>
+ </li>
+
+ <li>
+ <strong>Does the target CGI/SSI program exist?</strong>
+
+ <p class="indent">
+ If it doesn't exists, it can't very well be executed.
+ </p>
+ </li>
+
+ <li>
+ <strong>Is the target CGI/SSI program <em>NOT</em> writable
+ by anyone else?</strong>
+
+ <p class="indent">
+ We don't want to give anyone other than the owner the
+ ability to change the CGI/SSI program.
+ </p>
+ </li>
+
+ <li>
+ <strong>Is the target CGI/SSI program <em>NOT</em> setuid or
+ setgid?</strong>
+
+ <p class="indent">
+ We do not want to execute programs that will then change
+ our UID/GID again.
+ </p>
+ </li>
+
+ <li>
+ <strong>Is the target user/group the same as the program's
+ user/group?</strong>
+
+ <p class="indent">
+ Is the user the owner of the file?
+ </p>
+ </li>
+
+ <li>
+ <strong>Can we successfully clean the process environment
+ to ensure safe operations?</strong>
+
+ <p class="indent">
+ 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).
+ </p>
+ </li>
+
+ <li>
+ <strong>Can we successfully become the target CGI/SSI program
+ and execute?</strong>
+
+ <p class="indent">
+ Here is where suEXEC ends and the target CGI/SSI program begins.
+ </p>
+ </li>
+ </ol>
+
+ <p>This is the standard operation of 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>
+</div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
+<div class="section">
+<h2><a name="install" id="install">Configuring & Installing
+ suEXEC</a></h2>
+
+ <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
+ <code>--with-suexec-xxxxx</code> option has to be provided
+ together with the <code>--enable-suexec</code> 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 <code>suexec</code> 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
+ httpd normally runs. This is the only user allowed to
+ execute the suEXEC wrapper.</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" <code class="directive"><a href="./mod/mod_userdir.html#userdir">UserDir</a></code>
+ directive (ie. one without a "*" in it) this should be set to the same
+ value. suEXEC will not work properly in cases where the <code class="directive"><a href="./mod/mod_userdir.html#userdir">UserDir</a></code> directive points to
+ a location that is not the same as the user's home directory
+ as referenced in the <code>passwd</code> file. Default value is
+ "<code>public_html</code>".<br />
+ If you have virtual hosts with a different <code class="directive"><a href="./mod/mod_userdir.html#userdir">UserDir</a></code> 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 httpd. This will be
+ the only hierarchy (aside from <code class="directive"><a href="./mod/mod_userdir.html#userdir">UserDir</a></code>s) that can be used for suEXEC behavior. The
+ default directory is the <code>--datadir</code> value with the suffix
+ "<code>/htdocs</code>", <em>e.g.</em> if you configure with
+ "<code>--datadir=/home/apache</code>" the directory
+ "<code>/home/apache/htdocs</code>" 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
+ "<code>suexec_log</code>" and located in your standard logfile
+ directory (<code>--logfiledir</code>).</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
+ "<code>/usr/local/bin:/usr/bin:/bin</code>".</dd>
+ </dl>
+
+ <h3>Compiling and installing the suEXEC wrapper</h3>
+
+
+ <p>If you have enabled the suEXEC feature with the
+ <code>--enable-suexec</code> option the <code>suexec</code> binary
+ (together with httpd itself) is automatically built if you execute
+ the <code>make</code> command.</p>
+
+ <p>After all components have been built you can execute the
+ command <code>make install</code> to install them. The binary image
+ <code>suexec</code> is installed in the directory defined by the
+ <code>--sbindir</code> option. The default location is
+ "/usr/local/apache2/bin/suexec".</p>
+
+ <p>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>
+
+
+ <h3>Setting paranoid permissions</h3>
+
+
+ <p>Although the suEXEC wrapper will check to ensure that its
+ caller is the correct user as specified with the
+ <code>--with-suexec-caller</code> <code class="program"><a href="./programs/configure.html">configure</a></code>
+ option, there is
+ always the possibility that a system or library call suEXEC uses
+ before this check may be exploitable on your system. To counter
+ this, and because it is best-practise in general, you should use
+ filesystem permissions to ensure that only the group httpd
+ runs as may execute suEXEC.</p>
+
+ <p>If for example, your web server is configured to run as:</p>
+
+ <pre class="prettyprint lang-config">
+User www
+Group webgroup
+ </pre>
+
+
+ <p>and <code class="program"><a href="./programs/suexec.html">suexec</a></code> is installed at
+ "/usr/local/apache2/bin/suexec", you should run:</p>
+
+ <div class="example"><p><code>
+ chgrp webgroup /usr/local/apache2/bin/suexec<br />
+ chmod 4750 /usr/local/apache2/bin/suexec<br />
+ </code></p></div>
+
+ <p>This will ensure that only the group httpd runs as can even
+ execute the suEXEC wrapper.</p>
+
+</div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
+<div class="section">
+<h2><a name="enable" id="enable">Enabling & Disabling
+ suEXEC</a></h2>
+
+ <p>Upon startup of httpd, it looks for the file
+ <code class="program"><a href="./programs/suexec.html">suexec</a></code> in the directory defined by the
+ <code>--sbindir</code> option (default is
+ "/usr/local/apache/sbin/suexec"). If httpd finds a properly
+ configured suEXEC wrapper, it will print the following message
+ to the error log:</p>
+
+<div class="example"><p><code>
+ [notice] suEXEC mechanism enabled (wrapper: <var>/path/to/suexec</var>)
+</code></p></div>
+
+ <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 HTTP Server is already running you must kill and
+ restart httpd. 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
+ httpd after you have removed the <code class="program"><a href="./programs/suexec.html">suexec</a></code> file.</p>
+</div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
+<div class="section">
+<h2><a name="usage" id="usage">Using suEXEC</a></h2>
+
+ <p>Requests for CGI programs will call the suEXEC wrapper only if
+ they are for a virtual host containing a <code class="directive"><a href="./mod/mod_suexec.html#suexecusergroup">SuexecUserGroup</a></code> directive or if
+ they are processed by <code class="module"><a href="./mod/mod_userdir.html">mod_userdir</a></code>.</p>
+
+ <p><strong>Virtual Hosts:</strong><br /> One way to use the suEXEC
+ wrapper is through the <code class="directive"><a href="./mod/mod_suexec.html#suexecusergroup">SuexecUserGroup</a></code> directive in
+ <code class="directive"><a href="./mod/core.html#virtualhost">VirtualHost</a></code> 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 class="directive"><a href="./mod/core.html#virtualhost"><VirtualHost></a></code>. If this
+ directive is not specified for a <code class="directive"><a href="./mod/core.html#virtualhost"><VirtualHost></a></code> then the main server userid
+ is assumed.</p>
+
+ <p><strong>User directories:</strong><br /> Requests that are
+ processed by <code class="module"><a href="./mod/mod_userdir.html">mod_userdir</a></code> will call the suEXEC
+ wrapper to execute CGI programs under the userid of the requested
+ user directory. 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. See also the
+ <code>--with-suexec-userdir</code> <a href="#install">compile
+ time option</a>.</p> </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
+<div class="section">
+<h2><a name="debug" id="debug">Debugging suEXEC</a></h2>
+
+ <p>The suEXEC wrapper will write log information
+ to the file defined with the <code>--with-suexec-logfile</code>
+ 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>
+
+</div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
+<div class="section">
+<h2><a name="jabberwock" id="jabberwock">Beware the Jabberwock:
+ Warnings & Examples</a></h2>
+
+ <p><strong>NOTE!</strong> This section may not be
+ complete. For the latest revision of this section of the
+ documentation, see the <a href="http://httpd.apache.org/docs/trunk/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
+
+ <p class="indent">
+ 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 httpd
+ document hierarchy to take advantage of suEXEC for
+ VirtualHosts. (Example forthcoming.)
+ </p>
+ </li>
+
+ <li>
+ suEXEC's PATH environment variable
+
+ <p class="indent">
+ 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.
+ </p>
+ </li>
+
+ <li>
+ Altering the suEXEC code
+
+ <p class="indent">
+ 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.
+ </p>
+ </li>
+ </ul>
+
+</div></div>
+<div class="bottomlang">
+<p><span>Available Languages: </span><a href="./en/suexec.html" title="English"> en </a> |
+<a href="./fr/suexec.html" hreflang="fr" rel="alternate" title="Français"> fr </a> |
+<a href="./ja/suexec.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
+<a href="./ko/suexec.html" hreflang="ko" rel="alternate" title="Korean"> ko </a> |
+<a href="./tr/suexec.html" hreflang="tr" rel="alternate" title="Türkçe"> tr </a></p>
+</div><div class="top"><a href="#page-header"><img src="./images/up.gif" alt="top" /></a></div><div class="section"><h2><a id="comments_section" name="comments_section">Comments</a></h2><div class="warning"><strong>This section is experimental!</strong><br />Comments placed here should not be expected
+to last beyond the testing phase of this system, nor do we in any way guarantee that we'll read them.</div>
+<script type="text/javascript"><!--//--><![CDATA[//><!--
+var disqus_shortname = 'httpd';
+var disqus_identifier = 'http://httpd.apache.org/docs/2.4/suexec.html.en';
+(function(w, d) {
+ if (w.location.hostname.toLowerCase() == "httpd.apache.org") {
+ d.write('<div id="disqus_thread"><\/div>');
+ var s = d.createElement('script');
+ s.type = 'text/javascript';
+ s.async = true;
+ s.src = 'http' + '://' + disqus_shortname + '.disqus.com/embed.js';
+ (d.getElementsByTagName('head')[0] || d.getElementsByTagName('body')[0]).appendChild(s);
+ }
+ else {
+ d.write('<div id="disqus_thread">Comments have been disabled for offline viewing.<\/div>');
+ }
+})(window, document);
+//--><!]]></script></div><div id="footer">
+<p class="apache">Copyright 2012 The Apache Software Foundation.<br />Licensed under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p>
+<p class="menu"><a href="./mod/">Modules</a> | <a href="./mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="./glossary.html">Glossary</a> | <a href="./sitemap.html">Sitemap</a></p></div><script type="text/javascript"><!--//--><![CDATA[//><!--
+if (typeof(prettyPrint) !== 'undefined') {
+ prettyPrint();
+}
+//--><!]]></script>
+</body></html>
\ No newline at end of file
projects / apache / blobdiff