Re: Using views for row-level access control is leaky

On Fri, 2009-10-23 at 11:30 +0300, Heikki Linnakangas wrote:

> The most user-friendly and backwards-compatible (though not necessarily
> back-patchable) approach I can see is:
> 
> 1. If the user has read access to all the underlying tables, plan it
> like we do today.

For me, it would make most sense to explicitly mark Views as being
security views. That way planning need only change when we are
optimizing a query that accesses a view with plan security enabled.

ALTER VIEW foo ENABLE PLAN SECURITY;

That is much clearer and easily to verify/audit, so more secure.

Also, we should presume that any function created with SECURITY DEFINER
and created by a superuser would have plan security, so we don't need to
annotate lots of old code to work securely. Annotating the built-in
functions is a lot easier.

> 2. If the view refers only one table (as a typical Veil view does), plan
> it like we do today but enforce that view conditions are evaluated first
> in the Filter. Notably, allow using any user-supplied conditions as
> index quals if there's a matching index.
> 
> 3. Otherwise fully materialize the view.

So if we join a normal table or a view to a secure view then only the
secure view part would be materialized? Or do you mean the whole query
would be materialized?

-- Simon Riggs           www.2ndQuadrant.com