1484298 - Update the RNG in FuzzyFox to something better

Status: RESOLVED INCOMPLETE

(Core :: DOM: Security, enhancement, P3)

Description

[Tom Ritter [:tjr] (OOTO until April)]

In Bug 1432429  we're (probably) landing it with rand() as the underlying RNG.  That's pretty cruddy.  

Best case we would use a cryptographically secure RNG, like we do for Reduce Timer Precision.  However that's probably going to be prohibitively expensive since, unlike RTP, we run FuzzyFox all the time very frequently.

We could use a decent hash function (like Murmur Hash) that is not secure though. It would be pretty difficult to exploit a non-cryptographically secure hash, so we might be able to get away with it.

Comment 1

[Chris Peterson [:cpeterson]]

You can seed the new RNG with MFBT's new RandomUint64() function, which was extracted (in bug 1402282) from SpiderMonkey's code that called the operating system's secure RNG.