From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
cc: Stephen Frost <sfrost@snowman.net>, Josh Berkus <josh@agliodbs.com>,
 Kohei KaiGai <kaigai@kaigai.gr.jp>, "ktm@rice.edu" <ktm@rice.edu>,
 Alexander Korotkov <aekorotkov@gmail.com>,
 Oleg Bartunov <obartunov@gmail.com>, Greg Smith <greg@2ndquadrant.com>,
 PgHacker <pgsql-hackers@postgresql.org>
Subject: Re: [v9.4] row level security
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Comments: In-reply-to Robert Haas <robertmhaas@gmail.com>
 message dated "Wed, 04 Sep 2013 10:35:05 -0400"
Date: Wed, 04 Sep 2013 10:45:56 -0400
Message-ID: <1398.1378305956@sss.pgh.pa.us>
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Sender: pgsql-hackers-owner@postgresql.org

Robert Haas <robertmhaas@gmail.com> writes:
> On Fri, Aug 30, 2013 at 3:43 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> I think it's entirely sensible to question whether we should reject (not
>> "hold up") RLS if it has major covert-channel problems.

> We've already had this argument before, about the security_barrier
> view stuff, and that code got committed and is already released.  So
> the horse is already out of the barn and no amount of wishing will put
> it back in.

Well, the security-barrier view stuff did not present itself as a 100%
solution.  But perhaps more to the point, it was conceptually simple to
implement, ie don't flatten views if they have this bit set, and don't
push down quals into such sub-selects unless they're marked leakproof.

> I haven't reviewed this patch in a long time, but I would
> expect that it's basically just reusing that same infrastructure; in
> fact, I'd expect that it's little more than syntactic sugar around
> that infrastructure.

I've not read it in great detail, but it isn't that.  It's whacking the
planner around in ways that I have no confidence in, and probably still
wouldn't have any confidence in if they'd been adequately documented.

			regards, tom lane


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