Re: [v9.2] Fix leaky-view problem, part 2

On Wed, Jul 20, 2011 at 09:02:59AM +0200, Yeb Havinga wrote:
> On 2011-07-09 09:14, Kohei KaiGai wrote:
>> OK, I'll try to modify the patch according to the flag of pg_proc design.
>> As long as the default of user-defined function is off, and we provide
>> built-in functions
>> with appropriate configurations, it seems to me the burden of DBA is
>> quite limited.
>
> A different solution to the leaky view problem could be to check access
> to a tuple at or near the heaptuple visibility level, in addition to
> adding tuple access filter conditions to the query. This would have both
> the possible performance benefits of the query rewriting solution, as
> the everything is filtered before further processing at the heaptuple
> visibility level. Fixing leaky views is not needed because they don't
> exist in this case, the code is straightforward, and there's less change
> of future security bugs by either misconfiguration of leakproof
> functions or code that might introduce another leak path.

The SQL-level semantics of the view define the access rules in question. How
would you translate that into tests to apply at a lower level?

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Noah Misch http://www.2ndQuadrant.com/
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