From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rick Jones Subject: Re: [RFC/PATCH] "strict" ipv4 reassembly Date: Tue, 17 May 2005 15:23:49 -0700 Message-ID: <428A6EF5.9080509@hp.com> References: <20050517202730.GA79960@muc.de> <20050517.140245.71090021.davem@davemloft.net> <428A613F.1020303@hp.com> <20050517.151239.74747463.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Cc: netdev-bounce@oss.sgi.com Return-path: To: netdev@oss.sgi.com In-Reply-To: <20050517.151239.74747463.davem@davemloft.net> Sender: netdev-bounce@oss.sgi.com Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org David S.Miller wrote: > From: Rick Jones > Date: Tue, 17 May 2005 14:25:19 -0700 > > >>just how much extra overhead would there be to track the interarrival time of ip >>datagram fragments and would that allow someone to make a guess as to how long >>to reasonably wait for all the fragments to arrive? (or did I miss that being >>shot-down already?) > > > I spam you with fragments tightly interspaced matching a known > shost/dhost/ID tuple, lowering your interarrival estimate. The > legitimate fragment source can thus never get his fragments in > before the timer expires. > > Every other one of these IP fragmentation ideas tends to have > some DoS hole in it. Are the holes any larger than the existing ones? I've no idea, and perhaps the only answer is indeed to say "Then don't do that (fragment)!" rick jones