| From: | KaiGai Kohei <kaigai(at)kaigai(dot)gr(dot)jp> |
|---|---|
| To: | Richard Huxton <dev(at)archonet(dot)com> |
| Cc: | Greg Smith <gsmith(at)gregsmith(dot)com>, KaiGai Kohei <kaigai(at)ak(dot)jp(dot)nec(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Joshua Brindle <method(at)manicmethod(dot)com>, Josh Berkus <josh(at)agliodbs(dot)com>, Stephen Frost <sfrost(at)snowman(dot)net>, Gregory Stark <stark(at)enterprisedb(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, Simon Riggs <simon(at)2ndQuadrant(dot)com>, Ron Mayer <rm_pg(at)cheapcomplexdevices(dot)com>, "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>, Merlin Moncure <mmoncure(at)gmail(dot)com>, "Jonah H(dot) Harris" <jonah(dot)harris(at)gmail(dot)com>, Bruce Momjian <bruce(at)momjian(dot)us>, Bernd Helmle <mailings(at)oopsware(dot)de>, Peter Eisentraut <peter_e(at)gmx(dot)net>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: 8.4 release planning |
| Date: | 2009-01-28 10:26:16 |
| Message-ID: | 498032C8.4010105@kaigai.gr.jp |
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| Lists: | pgsql-hackers |
Richard Huxton wrote:
> Greg Smith wrote:
>> Where I suspect this is all is going to settle down into is that if 1)
>> the SE GUC is on and 2) one of the tables in a join has rows filtered,
>> then you can expect that a) it's possible that the result will leak
>> information, which certainly need to be documented,
>
> As far as I can tell this is the case however you hide the information.
> If you implemented it with views you'll have the same issue. If you hide
> the existence of project p_id="TOPSECRET01" and people can run inserts
> then they can spot it. Likewise, it you have fkey references to the row
> then deletions can be used to spot it.
>
It is a covert channel discussion.
At least, SE-PostgreSQL does not care about hiding its existence,
so it does not prevent user to infer the existence of a tuple
with same key value, using PK confliction.
(Please note that he must have a info about PK value or lucky
to make a key confliction.)
But, it enables to prevent unclassified user to read the tuple,
and him to know an info the tuple contains "p_id=TOPSECRET01" as
a result of this read action.
Thanks,
--
KaiGai Kohei <kaigai(at)kaigai(dot)gr(dot)jp>
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