The recently leaked Android 4.3 firmware version has already been rooted, before actually being officially rolled out by Google.
The news comes from xda-developers – where else? – which reports that xda Elite Recognized Developer Chainfire has managed to adapt his SuperSU root app for Android 4.3.
The root works on the Galaxy S4 Google Edition version running the Android 4.3 OS that leaked a few days ago (JWR66N.S005.130625) and is the first Android 4.3 root out there, Chainfire said in a detailed explanation on Google+.
According to the developer, it’s not clear whether the protections in place are Android 4.3 defaults or “Samsung’s doing,” but the root required “quite a few mods to SuperSU:”
It remains to be seen if all of the protections that have been circumvented have been Samsung's doing (as is normal for Samsung pre-release leaked firmwares), or if some of them are actually normal for Android 4.3.
For example, Android processes have their binding set of capabilities 0'd out. I've not personally seen that before on other firmwares, so I'm not sure if that's Samsung's doing or something 4.3. It prevents processes from performing certain actions - evenif the process manages to execute code as root user - like mounting the system read/write. Just to be clear, this root does not suffer from this issue.
However, all features are “fully operational,” so if you have a Galaxy S4 and want to install the Android 4.3 leak you’ll be happy to know it can also be rooted.
Like always with root and/or custom ROMs, we’ll remind you that you’re the only person responsible for whatever happens during such procedures with your smartphones and/or tablets. However, since you’re entitled to do whatever you like to your devices, make sure you back up your data and follow the available instructions closely (links in the Source section following the post).
That said, Android 4.3 is still not official, so we’re back to waiting for Google to actually announce and release it.