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5a58787efeb02a1c3f06569d019ad81fd2efa06end<p class="menu"><a href="/mod/">Modules</a> | <a href="/mod/directives.html">Directives</a> | <a href="/faq/">FAQ</a> | <a href="/glossary.html">Glossary</a> | <a href="/sitemap.html">Sitemap</a></p>
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5a58787efeb02a1c3f06569d019ad81fd2efa06end<a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs-project/">Documentation</a> > <a href="./">Version 2.1</a></div><div id="page-content"><div id="preamble"><h1>suEXEC Support</h1>
3b3b7fc78d1f5bfc2769903375050048ff41ff26nd<p><span>Available Languages: </span><a href="/en/suexec.html"> en </a> | <a href="/ja/suexec.html"> ja </a></p>
a30b4d95058922cb01453fb07c5ac66d6544571eslive Apache users the ability
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen to run <strong>CGI</strong> and <strong>SSI</strong> programs
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen under user IDs different from the user ID of the calling
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen web-server. Normally, when a CGI or SSI program executes, it
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen runs as the same user who is running the web server.</p>
ca0e3098838c1f9aa77bcdfc3df99cf9aa0f9383slive <p>Used properly, this feature can reduce
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen considerably the security risks involved with allowing users to
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen develop and run private CGI or SSI programs. However, if suEXEC
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen is improperly configured, it can cause any number of problems
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen and possibly create new holes in your computer's security. If
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen you aren't familiar with managing setuid root programs and the
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen security issues they present, we highly recommend that you not
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen consider using suEXEC.</p>
5a58787efeb02a1c3f06569d019ad81fd2efa06end<div id="quickview"><ul id="toc"><li><img alt="" src="/images/down.gif" /> <a href="#before">Before we begin</a></li>
5a58787efeb02a1c3f06569d019ad81fd2efa06end<li><img alt="" src="/images/down.gif" /> <a href="#model">suEXEC Security Model</a></li>
5a58787efeb02a1c3f06569d019ad81fd2efa06end<li><img alt="" src="/images/down.gif" /> <a href="#install">Configuring & Installing
5a58787efeb02a1c3f06569d019ad81fd2efa06end<li><img alt="" src="/images/down.gif" /> <a href="#enable">Enabling & Disabling
5a58787efeb02a1c3f06569d019ad81fd2efa06end<li><img alt="" src="/images/down.gif" /> <a href="#usage">Using suEXEC</a></li>
5a58787efeb02a1c3f06569d019ad81fd2efa06end<li><img alt="" src="/images/down.gif" /> <a href="#debug">Debugging suEXEC</a></li>
5a58787efeb02a1c3f06569d019ad81fd2efa06end<li><img alt="" src="/images/down.gif" /> <a href="#jabberwock">Beware the Jabberwock:
5a58787efeb02a1c3f06569d019ad81fd2efa06end<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
ca0e3098838c1f9aa77bcdfc3df99cf9aa0f9383slive <p>Before jumping head-first into this document,
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen you should be aware of the assumptions made on the part of the
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen Apache Group and this document.</p>
ca0e3098838c1f9aa77bcdfc3df99cf9aa0f9383slive <p>First, it is assumed that you are using a UNIX
e884f58207082fa2136d5fc86635c31252338948erikabele derivative operating system that is capable of
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen <strong>setuid</strong> and <strong>setgid</strong> operations.
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen All command examples are given in this regard. Other platforms,
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen if they are capable of supporting suEXEC, may differ in their
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen configuration.</p>
ca0e3098838c1f9aa77bcdfc3df99cf9aa0f9383slive <p>Second, it is assumed you are familiar with
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen some basic concepts of your computer's security and its
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen administration. This involves an understanding of
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen <strong>setuid/setgid</strong> operations and the various
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen effects they may have on your system and its level of
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen security.</p>
ca0e3098838c1f9aa77bcdfc3df99cf9aa0f9383slive <p>Third, it is assumed that you are using an
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen <strong>unmodified</strong> version of suEXEC code. All code
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen for suEXEC has been carefully scrutinized and tested by the
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen developers as well as numerous beta testers. Every precaution
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen has been taken to ensure a simple yet solidly safe base of
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen code. Altering this code can cause unexpected problems and new
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen security risks. It is <strong>highly</strong> recommended you
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen not alter the suEXEC code unless you are well versed in the
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen particulars of security programming and are willing to share
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen your work with the Apache Group for consideration.</p>
ca0e3098838c1f9aa77bcdfc3df99cf9aa0f9383slive <p>Fourth, and last, it has been the decision of
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen the Apache Group to <strong>NOT</strong> make suEXEC part of
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen the default installation of Apache. To this end, suEXEC
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen configuration requires of the administrator careful attention
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen to details. After due consideration has been given to the
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen various settings for suEXEC, the administrator may install
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen suEXEC through normal installation methods. The values for
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen these settings need to be carefully determined and specified by
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen the administrator to properly maintain system security during
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen the use of suEXEC functionality. It is through this detailed
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen process that the Apache Group hopes to limit suEXEC
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen installation only to those who are careful and determined
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen enough to use it.</p>
5a58787efeb02a1c3f06569d019ad81fd2efa06end</div><div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
5a58787efeb02a1c3f06569d019ad81fd2efa06end<h2><a name="model" id="model">suEXEC Security Model</a></h2>
ca0e3098838c1f9aa77bcdfc3df99cf9aa0f9383slive <p>Before we begin configuring and installing
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen suEXEC, we will first discuss the security model you are about
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen to implement. By doing so, you may better understand what
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen exactly is going on inside suEXEC and what precautions are
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen taken to ensure your system's security.</p>
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen "wrapper" program that is called by the main Apache web server.
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen This wrapper is called when an HTTP request is made for a CGI
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen or SSI program that the administrator has designated to run as
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen a userid other than that of the main server. When such a
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen request is made, Apache provides the suEXEC wrapper with the
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen program's name and the user and group IDs under which the
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen program is to execute.</p>
ca0e3098838c1f9aa77bcdfc3df99cf9aa0f9383slive <p>The wrapper then employs the following process
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen to determine success or failure -- if any one of these
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen conditions fail, the program logs the failure and exits with an
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen error, otherwise it will continue:</p>
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen <strong>Was the wrapper called with the proper number of
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen arguments?</strong>
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen The wrapper will only execute if it is given the proper
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen number of arguments. The proper argument format is known
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen to the Apache web server. If the wrapper is not receiving
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen the proper number of arguments, it is either being
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen hacked, or there is something wrong with the suEXEC
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen portion of your Apache binary.
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen <strong>Is the user executing this wrapper a valid user of
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen this system?</strong>
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen This is to ensure that the user executing the wrapper is
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen truly a user of the system.
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen <strong>Is this valid user allowed to run the
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen wrapper?</strong>
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen Is this user the user allowed to run this wrapper? Only
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen one user (the Apache user) is allowed to execute this
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen <strong>Does the target program have an unsafe hierarchical
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen reference?</strong>
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen Does the target program contain a leading '/' or have a
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen '..' backreference? These are not allowed; the target
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen program must reside within the Apache webspace.
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen Does the target user exist?
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen Does the target group exist?
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen <strong>Is the target user <em>NOT</em> superuser?</strong>
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen Presently, suEXEC does not allow 'root' to execute
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen <strong>Is the target userid <em>ABOVE</em> the minimum ID
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen number?</strong>
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen The minimum user ID number is specified during
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen configuration. This allows you to set the lowest possible
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen userid that will be allowed to execute CGI/SSI programs.
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen This is useful to block out "system" accounts.
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen <strong>Is the target group <em>NOT</em> the superuser
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen group?</strong>
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen Presently, suEXEC does not allow the 'root' group to
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen <strong>Is the target groupid <em>ABOVE</em> the minimum ID
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen number?</strong>
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen The minimum group ID number is specified during
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen configuration. This allows you to set the lowest possible
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen groupid that will be allowed to execute CGI/SSI programs.
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen This is useful to block out "system" groups.
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen <strong>Can the wrapper successfully become the target user
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen and group?</strong>
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen Here is where the program becomes the target user and
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen group via setuid and setgid calls. The group access list
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen is also initialized with all of the groups of which the
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen user is a member.
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen <strong>Does the directory in which the program resides
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen exist?</strong>
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen If it doesn't exist, it can't very well contain files.
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen <strong>Is the directory within the Apache
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen webspace?</strong>
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen If the request is for a regular portion of the server, is
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen the requested directory within the server's document
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen root? If the request is for a UserDir, is the requested
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen directory within the user's document root?
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen <strong>Is the directory <em>NOT</em> writable by anyone
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen else?</strong>
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen We don't want to open up the directory to others; only
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen the owner user may be able to alter this directories
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen If it doesn't exists, it can't very well be executed.
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen <strong>Is the target program <em>NOT</em> writable by
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen anyone else?</strong>
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen We don't want to give anyone other than the owner the
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen ability to change the program.
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen setgid?</strong>
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen We do not want to execute programs that will then change
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen <strong>Is the target user/group the same as the program's
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen Is the user the owner of the file?
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen <strong>Can we successfully clean the process environment
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen to ensure safe operations?</strong>
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen suEXEC cleans the process' environment by establishing a
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen safe execution PATH (defined during configuration), as
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen well as only passing through those variables whose names
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen are listed in the safe environment list (also created
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen during configuration).
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen <strong>Can we successfully become the target program and
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen execute?</strong>
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen Here is where suEXEC ends and the target program begins.
e884f58207082fa2136d5fc86635c31252338948erikabele <p>This is the standard operation of the
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen suEXEC wrapper's security model. It is somewhat stringent and
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen can impose new limitations and guidelines for CGI/SSI design,
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen but it was developed carefully step-by-step with security in
ca0e3098838c1f9aa77bcdfc3df99cf9aa0f9383slive <p>For more information as to how this security
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen model can limit your possibilities in regards to server
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen configuration, as well as what security risks can be avoided
ca0e3098838c1f9aa77bcdfc3df99cf9aa0f9383slive with a proper suEXEC setup, see the <a href="#jabberwock">"Beware the Jabberwock"</a> section of this
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen document.</p>
5a58787efeb02a1c3f06569d019ad81fd2efa06end</div><div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
5a58787efeb02a1c3f06569d019ad81fd2efa06end<h2><a name="install" id="install">Configuring & Installing
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen <dd>This option enables the suEXEC feature which is never
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen installed or activated by default. At least one
5bb304d44f4a7046289c9c7dbeef63843bff9613rbowen --with-suexec-xxxxx option has to be provided together with the
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen --enable-suexec option to let APACI accept your request for
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen using the suEXEC feature.</dd>
687ebbe3d0eaa7361f6cb85f56a389cbbc2e5056aaron <dd>The path to the suexec binary must be hard-coded in
687ebbe3d0eaa7361f6cb85f56a389cbbc2e5056aaron the server for security reasons. Use this option to override
5bb304d44f4a7046289c9c7dbeef63843bff9613rbowen <dt><code>--with-suexec-caller=<em>UID</em></code></dt>
d0dd037bdab65b455b4056d58be501ca14e61dfemartin <dd>The <a href="mod/mpm_common.html#user">username</a> under which
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen Apache normally runs. This is the only user allowed to
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen execute this program.</dd>
5bb304d44f4a7046289c9c7dbeef63843bff9613rbowen <dt><code>--with-suexec-userdir=<em>DIR</em></code></dt>
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen <dd>Define to be the subdirectory under users' home
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen directories where suEXEC access should be allowed. All
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen executables under this directory will be executable by suEXEC
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen as the user so they should be "safe" programs. If you are
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen using a "simple" UserDir directive (ie. one without a "*" in
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen it) this should be set to the same value. suEXEC will not
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen work properly in cases where the UserDir directive points to
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen a location that is not the same as the user's home directory
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen as referenced in the passwd file. Default value is
181e56d8b348d301d615ccf5465ae600fee2867berikabele "public_html".<br />
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen If you have virtual hosts with a different UserDir for each,
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen you will need to define them to all reside in one parent
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen directory; then name that parent directory here. <strong>If
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen this is not defined properly, "~userdir" cgi requests will
ee8d84bbd543e3e808e81e4e802d960548ce30d1aaron <dt><code>--with-suexec-docroot=<em>DIR</em></code></dt>
ee8d84bbd543e3e808e81e4e802d960548ce30d1aaron <dd>Define as the DocumentRoot set for Apache. This will be
ee8d84bbd543e3e808e81e4e802d960548ce30d1aaron the only hierarchy (aside from UserDirs) that can be used for
ee8d84bbd543e3e808e81e4e802d960548ce30d1aaron suEXEC behavior. The default directory is the --datadir value
ee8d84bbd543e3e808e81e4e802d960548ce30d1aaron with the suffix "/htdocs", <em>e.g.</em> if you configure
ee8d84bbd543e3e808e81e4e802d960548ce30d1aaron with "<code>--datadir=/home/apache</code>" the directory
ee8d84bbd543e3e808e81e4e802d960548ce30d1aaron "/home/apache/htdocs" is used as document root for the suEXEC
ee8d84bbd543e3e808e81e4e802d960548ce30d1aaron wrapper.</dd>
5bb304d44f4a7046289c9c7dbeef63843bff9613rbowen <dt><code>--with-suexec-uidmin=<em>UID</em></code></dt>
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen <dd>Define this as the lowest UID allowed to be a target user
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen for suEXEC. For most systems, 500 or 100 is common. Default
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen value is 100.</dd>
5bb304d44f4a7046289c9c7dbeef63843bff9613rbowen <dt><code>--with-suexec-gidmin=<em>GID</em></code></dt>
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen <dd>Define this as the lowest GID allowed to be a target
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen group for suEXEC. For most systems, 100 is common and
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen therefore used as default value.</dd>
ee8d84bbd543e3e808e81e4e802d960548ce30d1aaron <dt><code>--with-suexec-logfile=<em>FILE</em></code></dt>
ee8d84bbd543e3e808e81e4e802d960548ce30d1aaron <dd>This defines the filename to which all suEXEC
ee8d84bbd543e3e808e81e4e802d960548ce30d1aaron transactions and errors are logged (useful for auditing and
ee8d84bbd543e3e808e81e4e802d960548ce30d1aaron debugging purposes). By default the logfile is named
ee8d84bbd543e3e808e81e4e802d960548ce30d1aaron "suexec_log" and located in your standard logfile directory
ee8d84bbd543e3e808e81e4e802d960548ce30d1aaron (--logfiledir).</dd>
5bb304d44f4a7046289c9c7dbeef63843bff9613rbowen <dt><code>--with-suexec-safepath=<em>PATH</em></code></dt>
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen <dd>Define a safe PATH environment to pass to CGI
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen executables. Default value is
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen Before you compile and install the suEXEC wrapper you can
181e56d8b348d301d615ccf5465ae600fee2867berikabele check the configuration with the --layout option.<br />
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen Example output:</p>
181e56d8b348d301d615ccf5465ae600fee2867berikabele suEXEC setup:<br />
181e56d8b348d301d615ccf5465ae600fee2867berikabele suexec binary: /usr/local/apache/sbin/suexec<br />
181e56d8b348d301d615ccf5465ae600fee2867berikabele document root: /usr/local/apache/share/htdocs<br />
181e56d8b348d301d615ccf5465ae600fee2867berikabele userdir suffix: public_html<br />
181e56d8b348d301d615ccf5465ae600fee2867berikabele logfile: /usr/local/apache/var/log/suexec_log<br />
181e56d8b348d301d615ccf5465ae600fee2867berikabele caller ID: www<br />
181e56d8b348d301d615ccf5465ae600fee2867berikabele minimum user ID: 100<br />
181e56d8b348d301d615ccf5465ae600fee2867berikabele minimum group ID: 100<br />
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen If you have enabled the suEXEC feature with the
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen --enable-suexec option the suexec binary (together with Apache
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen itself) is automatically built if you execute the command
181e56d8b348d301d615ccf5465ae600fee2867berikabele "make".<br />
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen After all components have been built you can execute the
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen command "make install" to install them. The binary image
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen "suexec" is installed in the directory defined by the --sbindir
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen option. Default location is
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen privileges</em></strong> for the installation step. In order
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen for the wrapper to set the user ID, it must be installed as
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen owner <code><em>root</em></code> and must have the setuserid
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen execution bit set for file modes.</p>
5a58787efeb02a1c3f06569d019ad81fd2efa06end</div><div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
ca0e3098838c1f9aa77bcdfc3df99cf9aa0f9383slive <p>Upon startup of Apache, it looks for the file
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen "suexec" in the "sbin" directory (default is
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen "/usr/local/apache/sbin/suexec"). If Apache finds a properly
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen configured suEXEC wrapper, it will print the following message
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen to the error log:</p>
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen [notice] suEXEC mechanism enabled (wrapper: <em>/path/to/suexec</em>)
ca0e3098838c1f9aa77bcdfc3df99cf9aa0f9383slive <p>If you don't see this message at server startup, the server is
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen most likely not finding the wrapper program where it expects
ca0e3098838c1f9aa77bcdfc3df99cf9aa0f9383slive it, or the executable is not installed <em>setuid root</em>.</p>
ca0e3098838c1f9aa77bcdfc3df99cf9aa0f9383slive <p>If you want to enable the suEXEC mechanism for the first time
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen and an Apache server is already running you must kill and
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen restart Apache. Restarting it with a simple HUP or USR1 signal
ca0e3098838c1f9aa77bcdfc3df99cf9aa0f9383slive will not be enough. </p>
ca0e3098838c1f9aa77bcdfc3df99cf9aa0f9383slive <p>If you want to disable suEXEC you should kill and restart
ca0e3098838c1f9aa77bcdfc3df99cf9aa0f9383slive Apache after you have removed the "suexec" file. </p>
5a58787efeb02a1c3f06569d019ad81fd2efa06end</div><div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
181e56d8b348d301d615ccf5465ae600fee2867berikabele <p><strong>Virtual Hosts:</strong><br /> One way to use the suEXEC
181e56d8b348d301d615ccf5465ae600fee2867berikabele wrapper is through the <code class="directive"><a href="/mod/mod_suexec.html#suexecusergroup">SuexecUserGroup</a></code> directive in
181e56d8b348d301d615ccf5465ae600fee2867berikabele <code class="directive"><a href="/mod/core.html#virtualhost">VirtualHost</a></code> definitions. By
ca0e3098838c1f9aa77bcdfc3df99cf9aa0f9383slive setting this directive to values different from the main server
ca0e3098838c1f9aa77bcdfc3df99cf9aa0f9383slive user ID, all requests for CGI resources will be executed as the
181e56d8b348d301d615ccf5465ae600fee2867berikabele <em>User</em> and <em>Group</em> defined for that <code class="directive"><a href="/mod/core.html#virtualhost"><VirtualHost></a></code>. If this
181e56d8b348d301d615ccf5465ae600fee2867berikabele directive is not specified for a <code class="directive"><a href="/mod/core.html#virtualhost"><VirtualHost></a></code> then the main server userid
ca0e3098838c1f9aa77bcdfc3df99cf9aa0f9383slive is assumed.</p>
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen The suEXEC wrapper can also be used to execute CGI programs as
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen the user to which the request is being directed. This is
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen accomplished by using the "<strong><code>~</code></strong>"
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen character prefixing the user ID for whom execution is desired.
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen The only requirement needed for this feature to work is for CGI
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen execution to be enabled for the user and that the script must
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen meet the scrutiny of the <a href="#model">security checks</a>
5a58787efeb02a1c3f06569d019ad81fd2efa06end</div><div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
ca0e3098838c1f9aa77bcdfc3df99cf9aa0f9383slive <p>The suEXEC wrapper will write log information
5bb304d44f4a7046289c9c7dbeef63843bff9613rbowen to the file defined with the --with-suexec-logfile option as
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen indicated above. If you feel you have configured and installed
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen the wrapper properly, have a look at this log and the error_log
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen for the server to see where you may have gone astray.</p>
5a58787efeb02a1c3f06569d019ad81fd2efa06end</div><div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
5a58787efeb02a1c3f06569d019ad81fd2efa06end<h2><a name="jabberwock" id="jabberwock">Beware the Jabberwock:
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen complete. For the latest revision of this section of the
4e191199a0aeab09d78df8f5579e745572e8b7bcwsanchez documentation, see the Apache Group's <a href="http://httpd.apache.org/docs-2.1/suexec.html">Online
ca0e3098838c1f9aa77bcdfc3df99cf9aa0f9383slive <p>There are a few points of interest regarding
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen the wrapper that can cause limitations on server setup. Please
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen review these before submitting any "bugs" regarding suEXEC.</p>
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen Hierarchy limitations
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen For security and efficiency reasons, all suexec requests
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen must remain within either a top-level document root for
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen virtual host requests, or one top-level personal document
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen root for userdir requests. For example, if you have four
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen VirtualHosts configured, you would need to structure all
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen of your VHosts' document roots off of one main Apache
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen document hierarchy to take advantage of suEXEC for
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen VirtualHosts. (Example forthcoming.)
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen suEXEC's PATH environment variable
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen This can be a dangerous thing to change. Make certain
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen every path you include in this define is a
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen <strong>trusted</strong> directory. You don't want to
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen open people up to having someone from across the world
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen running a trojan horse on them.
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen Altering the suEXEC code
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen Again, this can cause <strong>Big Trouble</strong> if you
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen try this without knowing what you are doing. Stay away
57d0156f7bbd9ea3a72342cf9912aba61d118702rbowen from it if at all possible.
3b3b7fc78d1f5bfc2769903375050048ff41ff26nd<p><span>Available Languages: </span><a href="/en/suexec.html"> en </a> | <a href="/ja/suexec.html"> ja </a></p>
5a58787efeb02a1c3f06569d019ad81fd2efa06end<p class="apache">Maintained by the <a href="http://httpd.apache.org/docs-project/">Apache HTTP Server Documentation Project</a></p>
5a58787efeb02a1c3f06569d019ad81fd2efa06end<p class="menu"><a href="/mod/">Modules</a> | <a href="/mod/directives.html">Directives</a> | <a href="/faq/">FAQ</a> | <a href="/glossary.html">Glossary</a> | <a href="/sitemap.html">Sitemap</a></p></div>