Re: random() (was Re: New GUC to sample log queries)

On Wed, Dec 26, 2018 at 6:39 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> The point here is not to be cryptographically strong at every single
> place where the backend might want a random number; I think we're
> all agreed that we don't need that.  To me, the point is to ensure that
> the user-accessible random sequence is kept separate from internal uses,
> and the potential security exposure in the new random-logging patch is
> what justifies getting more worried about this than we were before.

I agree that that's the point here.

> Now, we could probably fix that with some less intrusive patch than
> #define'ing random() --- in particular, if we give drandom and setseed
> their own private PRNG state, we've really fixed the security exposure
> without need to change anything else anywhere.  So maybe we should
> just do that and be happy.

+1. I don't like the idea of #define'ing random() myself.

We're already making fairly broad assumptions about our having control
of the backend's PRNG state within InitProcessGlobals(). How should
this affect the new drandom()/setseed() private state, if at all?

-- 
Peter Geoghegan