Editing WoW:Secure Execution and Tainting (section)

==Hooking and the hooksecurefunc function==

The taint model is the reason that 'hooking' as it is commonly done today can easily break lots of UI functionality, trying to hook a function that is used by secure code causes a tainted function to be called in the middle of an otherwise secure execution path, this then taints the execution path so that nothing following the hook can use secure functions - don't be too dismayed however, we've been given a tool to get around this. 

The new hooksecurefunc API function allows AddOn code to 'post hook' a secure global function, that is run another function after the original one has been run. So for example you could track calls to CastSpellByName using hooksecurefunc("CastSpellByName", mySpellCastTracker). The API replaces the original global function with its own secure hook function that calls the original function, saves its return values away, and then calls your hook function with the same arguments as the original function (any return values from your hook function are thrown away) and then it returns the return values from the original. 

The 'special' feature of this secure hook is that when your hook function is executed, it executes with the taint that was present at the time the hook was created, and when your hook function is done that taint is discarded and the original secure (or possibly tainted - you cannot use hooksecurefunc to REMOVE taint, just avoid it) execution mode is restored.