From mboxrd@z Thu Jan 1 00:00:00 1970 From: Herbert Xu Subject: Re: [GIT PULL v2] Open vSwitch Date: Thu, 1 Dec 2011 15:52:37 +0800 Message-ID: <20111201075237.GA12799@gondor.apana.org.au> References: <20111123075433.GA7928@gondor.apana.org.au> <1322050976.2039.125.camel@mojatatu> <20111128130409.GB16828@gondor.apana.org.au> <0199E0D51A61344794750DC57738F58E7586A74137@GVW1118EXC.americas.hpqcorp.net> <20111128145157.GA17678@gondor.apana.org.au> <20111130070219.GB32630@gondor.apana.org.au> <20111201072418.GA18436@verge.net.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jesse Gross , "Fischer, Anna" , "jhs@mojatatu.com" , David Miller , "netdev@vger.kernel.org" , "dev@openvswitch.org" To: Simon Horman Return-path: Received: from helcar.apana.org.au ([209.40.204.226]:42182 "EHLO fornost.hengli.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753107Ab1LAHw5 (ORCPT ); Thu, 1 Dec 2011 02:52:57 -0500 Content-Disposition: inline In-Reply-To: <20111201072418.GA18436@verge.net.au> Sender: netdev-owner@vger.kernel.org List-ID: On Thu, Dec 01, 2011 at 04:24:18PM +0900, Simon Horman wrote: > > So while I agree that optimizing the hash is a good idea. I don't believe > it is a bottle-neck at this point. Though I could be convinced otherwise if > long collision chains could be constructed with relatively few flows. > Something I had not considered until I rad your email just now. It's not an optimisation issue, but a security one. If you leave a hash like this with a constant seed, an attacker would have an infinite amount of time to find collisions. Rehashing isn't all that difficult. Cheers, -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt