This is a simple wrapper for a command that needs to executed as root, but called from a PHP web page.

It is installed with set-user-id permission, as root, so can be called by any user. This example constructs an iptables command to add or remove a firewall rule, but the technique could be adapted to provide any selection of specific privileged commands.

To compile:

$ make

To install, as root:

# make install

The example PHP page ipaddr.php shows how it can be used. This page gets the caller's IP address and checks whether it is in the Remote-workers chain, displaying the result. The caller can then click on a button to add or remove their current address by default.

Note that this is just an example, and such a page should only be accessible in an authenticated way.