Re: WINDOW RANGE patch versus leakproofness

On 30 January 2018 at 16:42, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> So I'm thinking that (a) we do not need to check for leaky functions used
> in window support, and (b) therefore there's no need to avoid leaky
> behavior in in_range support functions. Objections?
>

Yes, I concur. Since window functions can only appear in the SELECT
target list and ORDER BY clauses, they should never appear in a qual
that gets considered for push down, and thus contain_leaked_vars()
should never see a window function.

Moreover, contain_leaked_vars() is intentionally coded defensively, so
if it ever does somehow see a window function (or any other unexpected
node type) it will return true and the resulting qual/restrictinfo
will be marked leaky, and not pushed through security barriers.

Regards,
Dean