Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1VF5Zc-0007Zl-2J for pgsql-hackers@arkaria.postgresql.org; Thu, 29 Aug 2013 16:59:56 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.80) (envelope-from ) id 1VF5Zb-0001Mx-Ao for pgsql-hackers@arkaria.postgresql.org; Thu, 29 Aug 2013 16:59:55 +0000 Received: from makus.postgresql.org ([2001:4800:7903:4::125]) by malur.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1VF5ZZ-0001Mp-VQ for pgsql-hackers@postgresql.org; Thu, 29 Aug 2013 16:59:54 +0000 Received: from smtp.01.com ([199.36.142.181] helo=smtp-out-2.01.com) by makus.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1VF5ZS-0001xq-K0 for pgsql-hackers@postgresql.org; Thu, 29 Aug 2013 16:59:53 +0000 Received: from localhost (localhost [127.0.0.1]) by smtp-out-2.01.com (Postfix) with ESMTP id 645AC390198; Thu, 29 Aug 2013 11:59:45 -0500 (CDT) X-Virus-Scanned: amavisd-new at smtp-out-2.01.com Received: from smtp-out-2.01.com ([127.0.0.1]) by localhost (smtp-out-2.01.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id N6Ly_-BCQN50; Thu, 29 Aug 2013 11:59:45 -0500 (CDT) Received: from smtp-out-2.01.com (localhost [127.0.0.1]) by smtp-out-2.01.com (Postfix) with ESMTP id 43C9039019D; Thu, 29 Aug 2013 11:59:45 -0500 (CDT) Received: from localhost (localhost [127.0.0.1]) by smtp-out-2.01.com (Postfix) with ESMTP id 3026D39019C; Thu, 29 Aug 2013 11:59:45 -0500 (CDT) X-Virus-Scanned: amavisd-new at smtp-out-2.01.com Received: from smtp-out-2.01.com ([127.0.0.1]) by localhost (smtp-out-2.01.com [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id R3n4ND9AOVdP; Thu, 29 Aug 2013 11:59:45 -0500 (CDT) Received: from [172.47.23.103] (70-36-143-10.dsl.dynamic.sonic.net [70.36.143.10]) by smtp-out-2.01.com (Postfix) with ESMTPSA id 54962390198; Thu, 29 Aug 2013 11:59:42 -0500 (CDT) Message-ID: <521F7DFB.8060602@agliodbs.com> Date: Thu, 29 Aug 2013 09:59:39 -0700 From: Josh Berkus Organization: PostgreSQL Experts Inc. User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130803 Thunderbird/17.0.8 MIME-Version: 1.0 To: Kohei KaiGai CC: "ktm@rice.edu" , Alexander Korotkov , Oleg Bartunov , Greg Smith , PgHacker Subject: Re: [v9.4] row level security References: <51E8A8C1.2050700@2ndQuadrant.com> <20130719030347.GV15510@tamriel.snowman.net> <51E8ADD9.5020600@2ndQuadrant.com> <521D1C2B.8090503@2ndQuadrant.com> <20130829142321.GA30496@aart.rice.edu> In-Reply-To: X-Enigmail-Version: 1.5.2 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Pg-Spam-Score: 0.8 (/) List-Archive: List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: X-Mailing-List: pgsql-hackers Precedence: bulk Sender: pgsql-hackers-owner@postgresql.org Kaigai, > Although I didn't touch this task by myself, my senior colleague said that we > calculated some possible bandwidth of leakage as an evident when we ship > supercomputer system with MAC feature for customer who worry about security. > I'm not sure how to measure it. However, if we assume a human can run up to > 5 query per seconds, he needs 2-3 seconds to identify a particular integer value > less than 10000, it means bandwidth of this covert channel is less than 5bps. > I'm not sure whether enterprise-grade dbms has to care about these amount > of covert channel. Why are you assuming a human needs to do it? Given the explain vector, I could write a rather simple python or perl script which would find values by EXPLAIN leakage, at 1000 explain plans per minute. It's one thing to day "we can't solve this covert channel issue right now in this patch", but saying "we don't plan to solve it at all" is likely to doom the patch. I'm not sure what the solution would be, exactly. Deny permission for EXPLAIN on certain tables? Surely someone in the security community has discussed this? -- Josh Berkus PostgreSQL Experts Inc. http://pgexperts.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers