Re: FPW compression leaks information

On Tue, Jul 7, 2015 at 12:34 PM, Stephen Frost <sfrost@snowman.net> wrote:
> * Heikki Linnakangas (hlinnaka@iki.fi) wrote:
>> On 07/07/2015 04:31 PM, Stephen Frost wrote:
>> >The alternative is to have monitoring tools which are running as
>> >superuser, which, in my view at least, is far worse.
>>
>> Or don't enable fpw_compression for tables where the information
>> leak is a problem.
>
> My hope would be that we would enable FPW compression by default for
> everyone as a nice optimization.  Relegating it to a risky option which
> has to be tweaked on a per-table basis, but only for those tables where
> you don't mind the risk, makes a nice optimization nearly unusable for
> many environments.

No, only tables that have RLS (or the equivalent, like in the case of
pg_authid), where the leak may be meaningful.

The attack requires control over an adjacent (same page) row, but not
over the row being attacked. That's RLS.