CGIWrap - Installation Instructions

There are two sets of installation instructions here. The basic ones I use, and a real-world example config contributed by Piotr Klaban below.

Quick Installation

Look at the notes to see if there are any hints for your platform.

Issue "./configure --help" to find out the various configuration options. You will need to specify some of them. At the very least, you will want to specify "--with-httpd-user=USERID".

Type "./configure <options>" with whatever options you need..

Type "make"

If you specified the installation directory in the options, you can type "make install" to do all the following steps.

Copy cgiwrap executable to your servers cgi-bin directory

Make cgiwrap owned by root, executable by all, and setuid. (Note: This step must be performed while logged in as "root")

chown root cgiwrap
chmod 4755 cgiwrap

Hardlink or symlink nph-cgiwrap, nph-cgiwrapd, cgiwrapd to cgiwrap in the cgi-bin directory.

ln [-s] cgiwrap cgiwrapd
ln [-s] cgiwrap nph-cgiwrap
ln [-s] cgiwrap nph-cgiwrapd

You can, if you wish, install it with less permissive permissions. (Eg. 4750) But if you do this, make sure that the group of cgiwrap is the same as the group that the server runs as.

*VERY IMPORTANT* - Do NOT allow any non-trusted user to run scripts directly out of the main cgi-bin directory, as this will allow them to use cgiwrap to run any of the other users scripts. The reason for this is that if they can run scripts as the same userid as the web server, they can subvert some of cgiwrap's security checks to allow them to run other users scripts. I recommend not running ANY scripts on the web server directly, once you have cgiwrap installed.

Configuration Options

The following are options available with the 'configure' command. Items in boldface are highly recommended. Defaults can be seen by issuing './configure --help' or by looking at the 'config.h' file after you have run 'configure'.

At an absolute minimum, you will probably want to specify the '--with-install-dir' and '--with-httpd-user' options.

path to perl executable to use
Specify the name of the local contact
Specify the local contact's email address
Specify the local contact's phone number
Specify a URL for the local contact
Specify a URL for this site
Specify a URL for a local copy of the cgiwrap docs
Add the '-Wall' option for compilation with gcc, this is intended primarily for development debugging.
group to install cgiwrap as
path to installation directory - this should be the path to your server's cgi-bin directory
path relative to home dir for cgi scripts
define a central cgi script directory that is searched if the script is not found in a user directory. This can be used to make a single script available that will run as any user, however, this can be very dangerous if you're not extremely careful designing your script. Do not enable this unless you know what you're doing. It is not needed for normal usage.
define what userid the web server is running as - this is required
don't check to make sure cgiwrap is being run by server userid - this is not recommended
disable check for matching owner
disable check for matching group
disable check for setuid script
disable check for setgid script
disable check for group writable script
disable check for world writable script
disable check for symlinked script
enable check for a valid user shell
require that REDIRECT_URL be set in calling environment
chroots script to PATH prior to script execution, requires specific environment to be set up. See chroot docs for more details.
--with-minimum-uid=UID set the minimum uid of user that can use cgiwrap, defaults to 100
--with-minimum-gid=GID set the minimum gid or aux gid of user that can use cgiwrap - not enabled by default
enable logging script execution to syslog
enable logging script execution to file
prevent users from storing scripts in subdirs
don't redirect stderr to stdout in scripts
disable use of initgroups() to clear non-userid auxilliary groups
disable use of setgroups() to add userid's auxilliary groups
use a file to rewrite user directories
set PATH environment variable to STRING
set TZ environment variable to STRING
limit cpu time with setrlimit
limit total virtual memory with setrlimit
limit total available memory with setrlimit
limit writable file size with setrlimit
limit data segment size with setrlimit
limit stack segment size with setrlimit
limit core file size with setrlimit
limit resident set size with setrlimit
limit number of processes with setrlimit
limit number of open files with setrlimit
limit lockable memory with setrlimit
limit cgiwrap usage
limit cgiwrap usage
limit cgiwrap usage specific to each vhost, to restrict UnixTools.ORG, you would create the access file 'DIR/'.
limit cgiwrap usage specific to each vhost
allow specifying hosts in allow/deny files
enable afs setpag() support

Password Protected Installation

The following are pecial additional instructions for installing a copy of cgiwrap that allows users to create access controlled scripts. For this to work, you will need to have a single common password file that will be used by all authenticated scripts.

Re run configure, specify "public_html/auth-cgi-bin" instead of "public_html/cgi-bin" for the cgi directory.

Type make.

Create a new server cgi-bin directory called "auth-cgi-bin", and install this new copy of cgiwrap into that directory the same way you installed it into the cgi-bin directory. (4 copies, and set permissions). You will now be able to use the url: http://server/auth-cgi-bin/cgiwrap...

To enable access control, place a .htaccess or equivalent file in the auth-cgi-bin directory where cgiwrap is located, that requires authentication to get at any file in that directory, but will allow any valid user to get through.

Now, your users can simply check: 1. That their script was executed by them (eg. check the real uid of the script to make sure someone else wasn't running it by hand) 2. That the REMOTE_USER environment variable contains a user name that they want to allow to access the script.

Supplementary Configuration

If you enabled the access file checking, you need to make sure and create the necessary files.

If you enabled the user directory rewriting feature, you need to create the configuration file that you specified in the configure run.

Here is the real-world example, for those who have problems
with cgiwrap installing.


A. I use cgi-bin/ for global cgi scripts, you may choose /cgi-sys/ instead.
B. I have installed apache in /usr/local/apache/ directory, you may have
   it in different location (/etc/httpd/ etc.)
C. I use WWW as a user web directory ('UserDir WWW' Apache directive),
   you may choose public_html if you wish.
D. I allow users place .cgi and .php scripts everywhere under the WWW/ directory
   (--with-cgi-dir=WWW cgiwrap configuration option), you may choose another method.
E. I have system-wide html pages in /usr/local/apache/WWW/HTML
   ('DocumentRoot /usr/local/apache/WWW/HTML' apache directive)
   and system-wide cgi-bin/ directory in /usr/local/apache/WWW/cgi-bin/
   ('ScriptAlias' apache directive)

Make sure you have installed php, that you can run it from the command line,
and you see the '--enable-discard-path' configuration option in the output
of the following command:
  % php -i | grep configure
If not, then before/after installing cgiwrap, install php as a normal program
with the configuration option: --enable-discard-path

cgiwrap install procedure:

1. download and unpack cgiwrap archive

  % wget
  % gtar zxvf cgiwrap-3.8.tar.gz
  % cd cgiwrap-3.8

2. configure it:

- /usr/local/bin/php with /usr/bin/php or other location of your php program
- WWW (in --with-cgi-dir=WWW) with public_html i.e. your users web directory
- /usr/local/apache/WWW/cgi-bin with /home/httpd/cgi-sys if you use such a value
  for ScriptAlias
- with YOUR contact address
- www (in --with-httpd-user=www) with apache if you run web server as 'apache' user

./configure --with-check-shell --with-rlimit-core=0 --with-rlimit-cpu=60 \
--without-redirect-stderr --without-logging-file --with-perl=/usr/bin/perl \
--with-httpd-user=www --with-cgi-dir=WWW \
--with-install-dir=/usr/local/apache/WWW/cgi-bin --with-wall \ --with-php=/usr/local/bin/php \

  # wait ...
  # wait more until configure checks everything

3. run make

  %  make

That should output:

gcc -c -Wall -g -O2  -I. -I. debug.c
gcc -c -Wall -g -O2  -I. -I. util.c
util.c: In function `CheckUser':
util.c:370: warning: suggest parentheses around assignment used as truth value
util.c: In function `UserInFile':
util.c:1088: warning: subscript has type `char'
util.c:1096: warning: subscript has type `char'
gcc -c -Wall -g -O2  -I. -I. fetch.c
gcc -c -Wall -g -O2  -I. -I. stdutil.c
gcc -c -Wall -g -O2  -I. -I. msgs.c
gcc -o cgiwrap cgiwrap.o debug.o util.o fetch.o stdutil.o msgs.o   

4. install with 'make install':

  % make install

That would be executed (make install -n):

rm -f /usr/local/apache/WWW/cgi-bin/cgiwrap
rm -f /usr/local/apache/WWW/cgi-bin/cgiwrapd
rm -f /usr/local/apache/WWW/cgi-bin/nph-cgiwrap
rm -f /usr/local/apache/WWW/cgi-bin/nph-cgiwrapd
# rm -f /usr/local/apache/WWW/cgi-bin/php-cgiwrap
# rm -f /usr/local/apache/WWW/cgi-bin/php-cgiwrapd
cp cgiwrap /usr/local/apache/WWW/cgi-bin/cgiwrap
chown root /usr/local/apache/WWW/cgi-bin/cgiwrap
chgrp root /usr/local/apache/WWW/cgi-bin/cgiwrap
chmod 4755 /usr/local/apache/WWW/cgi-bin/cgiwrap
ln /usr/local/apache/WWW/cgi-bin/cgiwrap /usr/local/apache/WWW/cgi-bin/cgiwrapd
ln /usr/local/apache/WWW/cgi-bin/cgiwrap /usr/local/apache/WWW/cgi-bin/nph-cgiwrap
ln /usr/local/apache/WWW/cgi-bin/cgiwrap /usr/local/apache/WWW/cgi-bin/nph-cgiwrapd
# ln /usr/local/apache/WWW/cgi-bin/cgiwrap /usr/local/apache/WWW/cgi-bin/php-cgiwrap
# ln /usr/local/apache/WWW/cgi-bin/cgiwrap /usr/local/apache/WWW/cgi-bin/php-cgiwrapd

Then you see you have cgiwrap in the /usr/local/apache/WWW/cgi-bin/

5. Now configure Apache:

  % cd /usr/local/apache/conf     (on linux: % cd /etc/httpd/conf/)
  % vim httpd.conf                (or % pico httpd.conf)

5a) add these lines to global directives:

# change /usr/local/apache/WWW/cgi-bin/ to YOUR /cgi-bin/ real path
ScriptAlias /cgi-bin/ "/usr/local/apache/WWW/cgi-bin/"

AddHandler cgi-wrapper .php
AddHandler cgi-wrapper .cgi
Action cgi-wrapper /cgi-bin/cgiwrap

5b) do not run cgiwrap on .cgi scripts in the global /cgi-bin/ directory:

AllowOverride None
Options None
AddHandler cgi-script .cgi

5c) I have a phpMyAdmin installed in /user/local/apache/WWW/HTML/phpMyAdmin/,
and I want it to be run as a 'www' user from the /WWW/HTML/ directory

Action cgi-wrapper /cgi-bin/cgiwrap/www/HTML

5d) I have some Virtual Domains defined. Every user can have its own
    virtual domain. I want .cgi and .php scripts to be run as a specified user
    ('makler' in this situation):

DocumentRoot /home/[... home directory/WWW here ...]/makler/WWW
ErrorLog logs/klaban_error_log
CustomLog logs/klaban_access_log combined
Action cgi-wrapper /cgi-bin/cgiwrap/makler

# [... other configuration stuff discarded ...]

6. Test your configuration before Apache reload (you may use /etc/init.d/httpd
   instead of ~www/bin/apachectl):

  % ~www/bin/apachectl configtest
Syntax OK

7. Reload apache web server:

  % ~www/bin/apachectl stop    # (or: ~www/bin/apachectl restart)
  % ~www/bin/apachectl start

8. Test if the simple php script is executed OK:

8a) create php script - your php scripts should be owned by the user, not root:

  % su makler
  % echo '\n"; ?> HTML too' > ~makler/WWW/test-php.php

8b) point your web browser to:

  Now you should see:
php is OK
HTML too  

Piotr Klaban