From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH V2 net] net: fix tcp reset packet flowlabel for ipv6 Date: Mon, 24 Jul 2017 13:34:55 -0700 (PDT) Message-ID: <20170724.133455.562898067272108474.davem@davemloft.net> References: <25a0abdf61ab4698773d417af9e49fcd6e6559a4.1500393028.git.shli@fb.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, Kernel-team@fb.com, shli@fb.com, eric.dumazet@gmail.com, flo@fourcot.fr To: shli@kernel.org Return-path: Received: from shards.monkeyblade.net ([184.105.139.130]:42626 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753495AbdGXUe4 (ORCPT ); Mon, 24 Jul 2017 16:34:56 -0400 In-Reply-To: <25a0abdf61ab4698773d417af9e49fcd6e6559a4.1500393028.git.shli@fb.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Shaohua Li Date: Tue, 18 Jul 2017 12:03:37 -0700 > + /* Since this is being sent on the wire obfuscate hash a bit > + * to minimize possbility that any useful information to an > + * attacker is leaked. Only lower 20 bits are relevant. > + */ > + rol32(hash, 16); This doesn't help anything at all. I don't like things that try to give a sense of security (however little) but actually don't give any at all. I'd rather, therefore, that you remove this altogether. And note that maybe not using the same flow label prevents attacks of that nature, ever consider that?