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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 --
- introduced in Apache 1.2 -- provides Apache users the ability
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+<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
+ 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
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>
-
- <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,
- 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
- derivate operating system that is capable of
+ 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 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
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>
+ your work with the Apache HTTP Server development team for consideration.</p>
- <p align="LEFT">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
+ <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
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
+ process that we hope to limit suEXEC
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 align="CENTER"><strong><a href="suexec.html">BACK TO
- CONTENTS</a></strong></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>
- <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
- "wrapper" program that is called by the main Apache web server.
+ <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 provides the suEXEC wrapper with the
+ 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 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>
<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>
+ arguments?</strong>
- <blockquote>
+ <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 web server. If the wrapper is not receiving
+ 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 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>
+ portion of your Apache httpd binary.
+ </p>
</li>
<li>
<strong>Is this valid user allowed to run the
- wrapper?</strong>
+ wrapper?</strong>
- <blockquote>
+ <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.
- </blockquote>
+ </p>
</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>
+ <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>
+ <strong>Is the target user name valid?</strong>
- <blockquote>
+ <p class="indent">
Does the target user exist?
- </blockquote>
+ </p>
</li>
<li>
- <strong>Is the target group name valid?</strong>
+ <strong>Is the target group name valid?</strong>
- <blockquote>
+ <p class="indent">
Does the target group exist?
- </blockquote>
+ </p>
</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>
+
+ <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>
+ number?</strong>
- <blockquote>
+ <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.
- </blockquote>
+ </p>
</li>
<li>
<strong>Is the target group <em>NOT</em> the superuser
- group?</strong>
+ group?</strong>
- <blockquote>
- Presently, suEXEC does not allow the 'root' group to
- execute CGI/SSI programs.
- </blockquote>
+ <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>
+ number?</strong>
- <blockquote>
+ <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.
- </blockquote>
+ </p>
</li>
<li>
<strong>Can the wrapper successfully become the target user
- and group?</strong>
+ and group?</strong>
- <blockquote>
+ <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.
- </blockquote>
+ </p>
</li>
<li>
- <strong>Does the directory in which the program resides
- exist?</strong>
+ <strong>Can we change directory to the one in which the target
+ CGI/SSI program resides?</strong>
- <blockquote>
- If it doesn't exist, it can't very well contain files.
- </blockquote>
+ <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 Apache
- webspace?</strong>
+ <strong>Is the directory within the httpd webspace?</strong>
- <blockquote>
+ <p class="indent">
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>
+ 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>
+ else?</strong>
- <blockquote>
+ <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.
- </blockquote>
+ </p>
</li>
<li>
- <strong>Does the target program exist?</strong>
+ <strong>Does the target CGI/SSI program exist?</strong>
- <blockquote>
+ <p class="indent">
If it doesn't exists, it can't very well be executed.
- </blockquote>
+ </p>
</li>
<li>
- <strong>Is the target program <em>NOT</em> writable by
- anyone else?</strong>
+ <strong>Is the target CGI/SSI program <em>NOT</em> writable
+ by anyone else?</strong>
- <blockquote>
+ <p class="indent">
We don't want to give anyone other than the owner the
- ability to change the program.
- </blockquote>
+ ability to change the CGI/SSI program.
+ </p>
</li>
<li>
- <strong>Is the target program <em>NOT</em> setuid or
- setgid?</strong>
+ <strong>Is the target CGI/SSI program <em>NOT</em> setuid or
+ setgid?</strong>
- <blockquote>
+ <p class="indent">
We do not want to execute programs that will then change
our UID/GID again.
- </blockquote>
+ </p>
</li>
<li>
<strong>Is the target user/group the same as the program's
- user/group?</strong>
+ user/group?</strong>
- <blockquote>
+ <p class="indent">
Is the user the owner of the file?
- </blockquote>
+ </p>
</li>
<li>
<strong>Can we successfully clean the process environment
- to ensure safe operations?</strong>
+ to ensure safe operations?</strong>
- <blockquote>
+ <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).
- </blockquote>
+ </p>
</li>
<li>
- <strong>Can we successfully become the target program and
- execute?</strong>
+ <strong>Can we successfully become the target CGI/SSI program
+ and execute?</strong>
- <blockquote>
- Here is where suEXEC ends and the target program begins.
- </blockquote>
+ <p class="indent">
+ Here is where suEXEC ends and the target CGI/SSI program begins.
+ </p>
</li>
</ol>
- <br />
- <br />
-
- <p align="LEFT">This is the standard operation of the the
+ <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 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>
+</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 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>Here's where we begin the fun.</p>
- <p align="LEFT">Here's where we begin the fun. If you use
- Apache 1.2 or prefer to configure Apache 1.3 with the
- "<code>src/Configure</code>" script you have to edit the suEXEC
- header file and install the binary in its proper location
- manually. The following sections describe the configuration and
- installation for Apache 1.3 with the AutoConf-style interface
- (APACI).</p>
-
- <p align="LEFT"><strong>APACI's suEXEC configuration
+ <p><strong>suEXEC configuration
options</strong><br />
</p>
<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-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>
+ <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-docroot=<em>DIR</em></code></dt>
+ <dt><code>--with-suexec-bin=<em>PATH</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>
+ <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-logfile=<em>FILE</em></code></dt>
+ <dt><code>--with-suexec-caller=<em>UID</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>
+ <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>
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
+ 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 passwd file. Default value is
- "public_html".<br />
- If you have virtual hosts with a different UserDir for each,
+ 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
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
- "/usr/local/bin:/usr/bin:/bin".</dd>
+ "<code>/usr/local/bin:/usr/bin:/bin</code>".</dd>
</dl>
- <br />
- <br />
-
-
- <p align="LEFT"><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>
-<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 />
- 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>
-
- <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>
-
- <p align="LEFT">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
+
+ <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>
-<pre>
- [notice] suEXEC mechanism enabled (wrapper: <em>/path/to/suexec</em>)
-</pre>
- If you don't see this message at server startup, the server is
+
+<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>.
- <br />
- 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/mpm_common.html#user">User</a> and <a
- href="mod/mpm_common.html#group">Group</a> directives in <a
- href="mod/core.html#virtualhost">VirtualHost</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 <em>User</em> and <em>Group</em> defined for that
- <code><VirtualHost></code>. If only one or neither of
- these directives are specified for a
- <code><VirtualHost></code> 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>
-
- <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
- 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>
-
- <p align="LEFT"><strong>NOTE!</strong> This section may not be
+ 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 Apache Group's <a
- href="http://www.apache.org/docs/suexec.html">Online
+ documentation, see the <a href="http://httpd.apache.org/docs/trunk/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><strong>suEXEC Points Of Interest</strong></li>
<li>
- Hierarchy limitations
+ Hierarchy limitations
- <blockquote>
- For security and efficiency reasons, all suexec requests
+ <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 Apache
+ of your VHosts' document roots off of one main httpd
document hierarchy to take advantage of suEXEC for
VirtualHosts. (Example forthcoming.)
- </blockquote>
+ </p>
</li>
<li>
- suEXEC's PATH environment variable
+ suEXEC's PATH environment variable
- <blockquote>
+ <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.
- </blockquote>
+ </p>
</li>
<li>
- Altering the suEXEC code
+ Altering the suEXEC code
- <blockquote>
+ <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.
- </blockquote>
+ </p>
</li>
</ul>
- <p align="CENTER"><strong><a href="suexec.html">BACK TO
- CONTENTS</a></strong></p>
- <!--#include virtual="footer.html" -->
- </body>
-</html>
-
+</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>
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+<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[//><!--
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