What is the proper *Public authority for PHP.ini

[tomhambel]

We recently had an issue where our php.ini file somehow got overwritten. I noticed that the public authority on this file is read write execute, so I changed it to exclude. Each time I restart the Zend subsystem, the permissions of the file change back. Can someone please advise what the proper *public authority should be? Why would the system be changing this to allow public write access?