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| author | Yoshiki Hayashi <yoshiki@apache.org> | 2002-05-22 10:22:40 +0000 |
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| committer | Yoshiki Hayashi <yoshiki@apache.org> | 2002-05-22 10:22:40 +0000 |
| commit | f897e63cf5a213bec32245558cf47aa8cd1b3a07 (patch) | |
| tree | 056ba7cba9328c7135e9aea230cb379bc67e3220 /docs/manual/suexec.html | |
| parent | ee677e797ad2d35e0391160bd5ba1494ae40e2dc (diff) | |
| download | httpd-f897e63cf5a213bec32245558cf47aa8cd1b3a07.tar.gz | |
New Japanese translation. Forward port from 1.3.
git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@95214 13f79535-47bb-0310-9956-ffa450edef68
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| -rw-r--r-- | docs/manual/suexec.html | 620 |
1 files changed, 0 insertions, 620 deletions
diff --git a/docs/manual/suexec.html b/docs/manual/suexec.html deleted file mode 100644 index 0448c942ec..0000000000 --- a/docs/manual/suexec.html +++ /dev/null @@ -1,620 +0,0 @@ -<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" - "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> - -<html xmlns="http://www.w3.org/1999/xhtml"> - <head> - <meta name="generator" content="HTML Tidy, see www.w3.org" /> - - <title>Apache suEXEC Support</title> - </head> - <!-- Background white, links blue (unvisited), navy (visited), red (active) --> - - <body bgcolor="#FFFFFF" text="#000000" link="#0000FF" - vlink="#000080" alink="#FF0000"> - <!--#include virtual="header.html" --> - - <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 - to run <strong>CGI</strong> and <strong>SSI</strong> programs - under user IDs different from the user ID of the calling - web-server. Normally, when a CGI or SSI program executes, it - runs as the same user who is running the web server.</p> - - <p align="LEFT">Used properly, this feature can reduce - 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 - <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 - 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 - <strong>unmodified</strong> version of suEXEC code. All code - for suEXEC has been carefully scrutinized and tested by the - developers as well as numerous beta testers. Every precaution - has been taken to ensure a simple yet solidly safe base of - code. Altering this code can cause unexpected problems and new - security risks. It is <strong>highly</strong> recommended you - not alter the suEXEC code unless you are well versed in the - particulars of security programming and are willing to share - your work with the Apache Group for consideration.</p> - - <p 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 - configuration requires of the administrator careful attention - to details. After due consideration has been given to the - various settings for suEXEC, the administrator may install - suEXEC through normal installation methods. The values for - these settings need to be carefully determined and specified by - the administrator to properly maintain system security during - the use of suEXEC functionality. It is through this detailed - process that the Apache Group hopes to limit suEXEC - installation only to those who are careful and determined - enough to use it.</p> - - <p 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> - - <h3><a id="model" name="model">suEXEC Security Model</a></h3> - - <p align="LEFT">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. - This wrapper is called when an HTTP request is made for a CGI - or SSI program that the administrator has designated to run as - a userid other than that of the main server. When such a - request is made, Apache provides the suEXEC wrapper with the - program's name and the user and group IDs under which the - program is to execute.</p> - - <p align="LEFT">The wrapper then employs the following process - to determine success or failure -- if any one of these - conditions fail, the program logs the failure and exits with an - error, otherwise it will continue:</p> - - <ol> - <li> - <strong>Was the wrapper called with the proper number of - arguments?</strong> - - <blockquote> - The wrapper will only execute if it is given the proper - number of arguments. The proper argument format is known - to the Apache web server. If the wrapper is not receiving - the proper number of arguments, it is either being - hacked, or there is something wrong with the suEXEC - portion of your Apache binary. - </blockquote> - </li> - - <li> - <strong>Is the user executing this wrapper a valid user of - this system?</strong> - - <blockquote> - This is to ensure that the user executing the wrapper is - truly a user of the system. - </blockquote> - </li> - - <li> - <strong>Is this valid user allowed to run the - wrapper?</strong> - - <blockquote> - Is this user the user allowed to run this wrapper? Only - one user (the Apache user) is allowed to execute this - program. - </blockquote> - </li> - - <li> - <strong>Does the target program have an unsafe hierarchical - reference?</strong> - - <blockquote> - Does the target program contain a leading '/' or have a - '..' backreference? These are not allowed; the target - program must reside within the Apache webspace. - </blockquote> - </li> - - <li> - <strong>Is the target user name valid?</strong> - - <blockquote> - Does the target user exist? - </blockquote> - </li> - - <li> - <strong>Is the target group name valid?</strong> - - <blockquote> - Does the target group exist? - </blockquote> - </li> - - <li> - <strong>Is the target user <em>NOT</em> superuser?</strong> - - - <blockquote> - Presently, suEXEC does not allow 'root' to execute - CGI/SSI programs. - </blockquote> - </li> - - <li> - <strong>Is the target userid <em>ABOVE</em> the minimum ID - number?</strong> - - <blockquote> - The minimum user ID number is specified during - configuration. This allows you to set the lowest possible - userid that will be allowed to execute CGI/SSI programs. - This is useful to block out "system" accounts. - </blockquote> - </li> - - <li> - <strong>Is the target group <em>NOT</em> the superuser - group?</strong> - - <blockquote> - Presently, suEXEC does not allow the 'root' group to - execute CGI/SSI programs. - </blockquote> - </li> - - <li> - <strong>Is the target groupid <em>ABOVE</em> the minimum ID - number?</strong> - - <blockquote> - The minimum group ID number is specified during - configuration. This allows you to set the lowest possible - groupid that will be allowed to execute CGI/SSI programs. - This is useful to block out "system" groups. - </blockquote> - </li> - - <li> - <strong>Can the wrapper successfully become the target user - and group?</strong> - - <blockquote> - Here is where the program becomes the target user and - group via setuid and setgid calls. The group access list - is also initialized with all of the groups of which the - user is a member. - </blockquote> - </li> - - <li> - <strong>Does the directory in which the program resides - exist?</strong> - - <blockquote> - If it doesn't exist, it can't very well contain files. - </blockquote> - </li> - - <li> - <strong>Is the directory within the Apache - webspace?</strong> - - <blockquote> - If the request is for a regular portion of the server, is - the requested directory within the server's document - root? If the request is for a UserDir, is the requested - directory within the user's document root? - </blockquote> - </li> - - <li> - <strong>Is the directory <em>NOT</em> writable by anyone - else?</strong> - - <blockquote> - We don't want to open up the directory to others; only - the owner user may be able to alter this directories - contents. - </blockquote> - </li> - - <li> - <strong>Does the target program exist?</strong> - - <blockquote> - If it doesn't exists, it can't very well be executed. - </blockquote> - </li> - - <li> - <strong>Is the target program <em>NOT</em> writable by - anyone else?</strong> - - <blockquote> - We don't want to give anyone other than the owner the - ability to change the program. - </blockquote> - </li> - - <li> - <strong>Is the target program <em>NOT</em> setuid or - setgid?</strong> - - <blockquote> - We do not want to execute programs that will then change - our UID/GID again. - </blockquote> - </li> - - <li> - <strong>Is the target user/group the same as the program's - user/group?</strong> - - <blockquote> - Is the user the owner of the file? - </blockquote> - </li> - - <li> - <strong>Can we successfully clean the process environment - to ensure safe operations?</strong> - - <blockquote> - suEXEC cleans the process' environment by establishing a - safe execution PATH (defined during configuration), as - well as only passing through those variables whose names - are listed in the safe environment list (also created - during configuration). - </blockquote> - </li> - - <li> - <strong>Can we successfully become the target program and - execute?</strong> - - <blockquote> - Here is where suEXEC ends and the target program begins. - </blockquote> - </li> - </ol> - <br /> - <br /> - - - <p align="LEFT">This is the standard operation of the the - suEXEC wrapper's security model. It is somewhat stringent and - can impose new limitations and guidelines for CGI/SSI design, - but it was developed carefully step-by-step with security in - mind.</p> - - <p align="LEFT">For more information as to how this security - 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> - - <p align="CENTER"><strong><a href="suexec.html">BACK TO - CONTENTS</a></strong></p> - - <h3><a id="install" name="install">Configuring & Installing - suEXEC</a></h3> - - <p align="LEFT">Here's where we begin the fun. 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 - options</strong><br /> - </p> - - <dl> - <dt><code>--enable-suexec</code></dt> - - <dd>This option enables the suEXEC feature which is never - installed or activated by default. At least one - --with-suexec-xxxxx option has to be provided together with the - --enable-suexec option to let APACI accept your request for - using the suEXEC feature.</dd> - - <dt><code>--with-suexec-caller=<em>UID</em></code></dt> - - <dd>The <a href="mod/mpm_common.html#user">username</a> under which - Apache normally runs. This is the only user allowed to - execute this program.</dd> - - <dt><code>--with-suexec-docroot=<em>DIR</em></code></dt> - - <dd>Define as the DocumentRoot set for Apache. This will be - the only hierarchy (aside from UserDirs) that can be used for - suEXEC behavior. The default directory is the --datadir value - with the suffix "/htdocs", <em>e.g.</em> if you configure - with "<code>--datadir=/home/apache</code>" the directory - "/home/apache/htdocs" is used as document root for the suEXEC - wrapper.</dd> - - <dt><code>--with-suexec-logfile=<em>FILE</em></code></dt> - - <dd>This defines the filename to which all suEXEC - transactions and errors are logged (useful for auditing and - debugging purposes). By default the logfile is named - "suexec_log" and located in your standard logfile directory - (--logfiledir).</dd> - - <dt><code>--with-suexec-userdir=<em>DIR</em></code></dt> - - <dd>Define to be the subdirectory under users' home - directories where suEXEC access should be allowed. All - executables under this directory will be executable by suEXEC - as the user so they should be "safe" programs. If you are - using a "simple" UserDir directive (ie. one without a "*" in - it) this should be set to the same value. suEXEC will not - work properly in cases where the UserDir directive points to - a location that is not the same as the user's home directory - as referenced in the passwd file. Default value is - "public_html".<br /> - If you have virtual hosts with a different UserDir for each, - you will need to define them to all reside in one parent - directory; then name that parent directory here. <strong>If - this is not defined properly, "~userdir" cgi requests will - not work!</strong></dd> - - <dt><code>--with-suexec-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-safepath=<em>PATH</em></code></dt> - - <dd>Define a safe PATH environment to pass to CGI - executables. Default value is - "/usr/local/bin:/usr/bin:/bin".</dd> - </dl> - <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 - 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 - 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 - 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</a> version.</p> - - <p align="LEFT">There are a few points of interest regarding - the wrapper that can cause limitations on server setup. Please - review these before submitting any "bugs" regarding suEXEC.</p> - - <ul> - <li><strong>suEXEC Points Of Interest</strong></li> - - <li> - Hierarchy limitations - - <blockquote> - For security and efficiency reasons, all suexec requests - must remain within either a top-level document root for - virtual host requests, or one top-level personal document - root for userdir requests. For example, if you have four - VirtualHosts configured, you would need to structure all - of your VHosts' document roots off of one main Apache - document hierarchy to take advantage of suEXEC for - VirtualHosts. (Example forthcoming.) - </blockquote> - </li> - - <li> - suEXEC's PATH environment variable - - <blockquote> - This can be a dangerous thing to change. Make certain - every path you include in this define is a - <strong>trusted</strong> directory. You don't want to - open people up to having someone from across the world - running a trojan horse on them. - </blockquote> - </li> - - <li> - Altering the suEXEC code - - <blockquote> - Again, this can cause <strong>Big Trouble</strong> if you - try this without knowing what you are doing. Stay away - from it if at all possible. - </blockquote> - </li> - </ul> - - <p align="CENTER"><strong><a href="suexec.html">BACK TO - CONTENTS</a></strong></p> - <!--#include virtual="footer.html" --> - </body> -</html> - |