Customizing PHP Safe Mode

We’ll guide you through using PHP safe_mode and how-to enable it and to customize it for certain sites on your server. When using PHP as an Apache module, you can also change the configuration settings using directives in Apache configuration files (e.g. httpd.conf) and .htaccess files. PHP safe_mode is very important to in terms of server security because it restricts and disables the dangerous functions in PHP from the scripts like PHP Shell that can otherwise cause damages to your server and client sites.

Using PHP Safe_Mode

First of all we’ll take care of the files that you will edit, and make sure to have copy or backup .

Activate Safe Mode Globally

It is very simple to active safe mode on the entire server. All you need to do is just edit the php.ini file. If you can’t find where php.ini is or have multiple copies on your server the best thing to do is run phpinfo() to find it. Open up Notepad or your favorite HTML editor and paste in the following from this file.

http://www.webhostgear.com/phpinfo.phps

Save it as phpinfo.php and upload it to a website that you want to test on your server. Type in the URL and you’ll get a PHP configuration page telling you exactly where php.ini is located and all kinds of other useful information about the sites and servers configuration settings.

A few lines down you’ll see this:
Configuration File (php.ini) Path: /usr/local/Zend/etc/php.ini
Now that we know the location of php.ini we can proceed to edit it.

1) Open up php.ini in your shell with your favorite editing program.
pico /path to php/php.ini (replace with the path to your php.ini file)

2) Find the following line: safe_mode
Ctrl + W and type in: safe_mode

3) Turning safe mode on or off.
safe_mode = Off

You may active it by or turn it off by changing it to either On OR Off.
safe_mode = On

Good! Now save the file by ctrl + x  then y

4) Restart the Apache web server by
/etc/init.d/httpd restart

Now safe_mode is active on all your server accounts.

Activate Safe Mode Using Per Site Basis

Now if you have scripts that require safe mode off like Modernbill or any script doesn't work well with safe_mode on what you will do? Disable safe_mode on the entire server just for these scripts? This isn’t very practical when you can disable php safe mode per user account/site basis.

Let’s do it!
1) SSH to your server and login as root.

2) Then find the httpd.conf, normally it’s in /etc/httpd/conf/  or  /usr/local/apache/conf/
If it’s not in either of those places try search for it: locate httpd.conf

3) Then find the site you wish to edit.
Ctrl+W and type in the domain name

You should see something like this

<VirtualHost ***.***.***.***>
ServerAlias www.domain.net domain.net
ServerAdmin webmaster@domain.net
DocumentRoot /home/domain/public_html
BytesLog domlogs/domain.net-bytes_log
ServerName www.domain.net
User domain
Group domain
CustomLog domlogs/domain.net combined
ScriptAlias /cgi-bin/ /home/domain/public_html/cgi-bin/ 
</VirtualHost>

4) Now add this line:

php_admin_flag safe_mode Off

We have also found that the following works as well if the above does not but DO NOT USE BOTH, pick one!

php_admin_value safe_mode 0

to be like this :

<VirtualHost ***.***.***.***>
ServerAlias www.domain.net domain.net
ServerAdmin webmaster@domain.net
DocumentRoot /home/domain/public_html
php_admin_flag safe_mode Off
BytesLog domlogs/domain.net-bytes_log
ServerName www.domain.net
User domain
Group domain
CustomLog domlogs/domain.net combined
ScriptAlias /cgi-bin/ /home/domain/public_html/cgi-bin/ 
</VirtualHost>

5) Good :) Now save the changes.
Ctrl + X then Y

6) Restart the Apache web server by
/etc/init.d/httpd restart

Final Words

PHP Safe mode should be on by default on all your servers for added security. However there are some scripts that are not compatible with it on so you have to make an exception to some client sites. Make sure you know why they’re requesting to have it turned off because it is much more secure for everyone to have it on.

If you run into trouble after editing httpd.conf you can run the apachectl configtest
in shell. This will test the Apache configuration for errors and report them back to you if you can’t start it, very handy indeed!
More PHP customizing commands here: http://php.us.themoes.org/manual/en/configuration.changes.php

Contributed by ReRoot, edited by Ramprage