IMPORTANT INFORMATION
There was a serious vulnerability in certain CGI-based PHP setups that has gone unnoticed for at least 8 years.
For PHP this means that a request containing ?-s may dump the PHP source code for the page.
Make sure to update to current versions and/or use an .htaccess patch, both available here:
PHP 5.3.12 and PHP 5.4.2 Released:
http://www.php.net/archive/2012.php#id2012-05-03-1
NOTE: Running PHP as a CGI program will change the value of $_SERVER['SCRIPT_NAME']. When running via the (normal) mod_PHP mechanism, it will be set to the name of (actually, path to) the PHP script that's running. When running via CGI, it will instead point to the path of the CGI binary.
One of the most common reasons why you get 'No input file specified' (AKA 'the second most useful error message in the world') is that you have set 'doc_root' (in php.ini) to a value which is to the 'DocumentRoot' defined in the apache configuration.
This is the same for other webservers. For example, on lighttpd, make sure the 'server.document-root' value is the same as what is defined as 'doc_root' in php.ini.
In response to grange at club-internet dot fr:
There are a couple of errors in the mod_rewrite directives given. I found that the following works:
RewriteEngine on
RewriteCond %{ENV:REDIRECT_STATUS} !200
RewriteRule ^cgi-bin/php.cgi - [F]
I removed the = from the RewriteCond and took out the leading / from the RewriteRule.
I have noticed that some people have noted that running PHP as a CGI program can run slowly compared with a compiled in module. Some have noted that they want to use FastCGI but are hesitant. I found that using the Apache 2's CGID module was a great way to speed up performance almost to the same level as an "so"-installed PHP module but you get the added benefit of running each virtual host under it's own user and group.
In my testing I got 44 pages per second using PHP as a module and I got roughly the same performance (within 5%) running PHP as a CGI program through CGID.
CGID is also really easy to set up. Just add --enable-cgid to your Apache configure command and you're good to go. Just set up PHP as a CGI normally.
I'm sure that there's extra RAM used for this method but RAM is as cheap as borscht anyways so it shouldn't be a major factor when trying to speed up PHP CGI.
PHP CGI with VirtualHosts.
This is what I found out while trying to get php to work as CGI with Apache VirtualHosts.
By enabling 'force-cgiredirects', you *must*:
1) set 'cgi.fix_pathinfo=1' in php.ini
2) leave doc_root commented out (php.ini also)
If you miss item 1, the apache logs will show 'unexpected T_STRING' in the php binary.
If you miss item 2, you'll only see 'No input file specified.', instead of the expected output.
You can then turn on the php support for a particular vhost by defining:
Action php-script /cgi-bin/php
inside the corresponding <VirtualHost> directive.
PHP works with Apache and suEXEC like this:
(Assuming that suEXEC ist allready installed and working)
Install PHP as CGI binary (e.g. in /usr/local/bin/php)
(compile with --enable-force-cgi-redirect)
Create a Link inside cgi-bin directory to make php-cgi accessable:
cd /usr/local/apache/cgi-bin
ln /usr/local/bin/php php
Edit your httpd.conf file:
AddHandler php4-script .php
Action php4-script /cgi-bin/php
<VirtualHost 123.456.789.0:80>
User exampleuser
Group examplegroup
...
</VirtualHost>
Restart Apache
PHP-scripts are now called under the user-id of exampleuser and group-id of examplegroup.
a replacement for suexec is suphp (http://www.suphp.org).
"suPHP is a tool for executing PHP scripts with the permissions of their owners. It consists of an Apache module (mod_suphp) and a setuid root binary (suphp) that is called by the Apache module to change the uid of the process executing the PHP interpreter." (from the website)
I have setup a guide to installing PHP with SuEXEC in such a way that shebangs (!#/usr/bin/php4) are not needed. Hope this is of some help to you.
http://www.pookey.co.uk/php-security.xml
A tip for Windows-users
Just a tip for you so do not do the same mistake as I did:
I just found out that PHP first seem to look in the php-directory for php.ini, and if that file does not exist, it looks in the Windows directory.
I renamed the file php.ini-dist to php.ini and copied it to my Windows directory, and then I modified the infamous "cgi.force_redirect = 0" in the php.ini file located in the Windows directory, to make it work. But it did not because it reads from the "original" php.ini - So when I deleted this php.ini things started working again
If you are using php per cgi and have additionally mod_gzip enabled you have to disable mod_gzip for the php cgi binary to use --enable-cgi-redirect. mod_gzip sets the REDIRECT_STATUS always to 200 which makes it impossible for the php binary to know when it was called directly or when it was called by a redirect.
To use php-cgi with suexec it will be nice that each virtual host has ist's own php.ini. This goes with :
SetEnv PHPRC /var/www/server/www.test.com/conf
But suexec will kill this enviromet cause It don't know that it is "save" so you must edit the suexec.c for compiling ....
If you care about security, you are better of setting
register_globals = off
enable_track_vars = on (Always on from PHP4.0.3)
Default setting for variable order is
EGPCS
(ENV VARS/GET VARS/POST VARS/COOKIE VARS/SESSION VARS)
Imagine if you are rely on ENV VAR but it was orver written with GET/POST/COOKIE vars?
If you want to use suexec and reference your php interpreter via #!/usr/local/bin/php, be shure to compile php WITHOUT --enable-force-cgi-redirect.
This might seems obvious, but I spent 2 days on this :-(
suEXEC require CGI mode, and slow down the scripts. I did them like this:
1. Install php as DSO mode. (for max speed and low secure)
2. Make a seperate CGI install with --enable-force-cgi-redirect, place php to cgi-bin
3 For more secure with suEXEC, choose one of the following method:
3-1: Place a .htaccess file containing this to override main config:
AddType application/x-httpd-wphp php
Action application/x-httpd-wphp /cgi-bin/php
All php files in subdirectory will be protected.
3-2: add following in httpd.conf:
AddType application/x-httpd-wphp sphp
Action application/x-httpd-wphp /cgi-bin/php
then each sensitive php file should be renamed to .sphp
Add "php_value doc_root /home/user/html_docs" to each virtual host directive in httpd.conf
Better yet, use binfmt_misc: (linux only)
echo :php3:E::php3::/usr/bin/php: > /proc/sys/fs/binfmt_misc/register
Eliminates the need for the #! at the top of the file.