From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH 2/2] tcp: syncookies: reduce mss table to four values Date: Wed, 28 Aug 2013 18:22:00 -0400 (EDT) Message-ID: <20130828.182200.304733834519582086.davem@davemloft.net> References: <1377453242-4773-1-git-send-email-fw@strlen.de> <1377453242-4773-2-git-send-email-fw@strlen.de> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, jbohac@suse.cz To: fw@strlen.de Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:50608 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754636Ab3H1WWC (ORCPT ); Wed, 28 Aug 2013 18:22:02 -0400 In-Reply-To: <1377453242-4773-2-git-send-email-fw@strlen.de> Sender: netdev-owner@vger.kernel.org List-ID: From: Florian Westphal Date: Sun, 25 Aug 2013 19:54:02 +0200 > Halve mss table size to make blind cookie guessing more difficult. > This is sad since the tables were already small, but there > is little alternative except perhaps adding more precise mss information > in the tcp timestamp. Timestamps are unfortunately not ubiquitous. > > Guessing all possible cookie values still has 8-in 2**32 chance. > > Reported-by: Jakob Lell > Signed-off-by: Florian Westphal It seems you've decided to retain different sets of entries in these two tables. It is not at all obvious to me if this was intentional, and if so then why such a choice was made. Please clarify this. Thank you.