i developed a php application where users login and a singleton "controller" instance contains all of the user data like their options, permissions and so on. This controller is stored in session and will be always the same every page they change.
Now, i don't really use the SID so if the same user logs in from another pc, he will be able to have two sessions open at the same time, each one with its own SID and independent controllers.
What's the standard way to manage SID? Should i attach to each user their "active SID" in the database and checking against it every time they change page?
This way if they would log from another session they would have "session expired" error in the first one.
I'm using secure and https PHPSSID, if that matters.
Are there particular vulnerabilities issues i could face with this pattern?
thanks