From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net-next] tcp: RFC 5961 5.2 Blind Data Injection Attack Mitigation Date: Mon, 22 Oct 2012 15:11:31 -0400 (EDT) Message-ID: <20121022.151131.792891680432322007.davem@davemloft.net> References: <1350885431.8609.250.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, ncardwell@google.com, ycheng@google.com, hkchu@google.com To: eric.dumazet@gmail.com Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:32821 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751976Ab2JVTLg (ORCPT ); Mon, 22 Oct 2012 15:11:36 -0400 In-Reply-To: <1350885431.8609.250.camel@edumazet-glaptop> Sender: netdev-owner@vger.kernel.org List-ID: From: Eric Dumazet Date: Mon, 22 Oct 2012 07:57:11 +0200 > From: Eric Dumazet > > RFC 5961 5.2 [Blind Data Injection Attack].[Mitigation] > > All TCP stacks MAY implement the following mitigation. TCP stacks > that implement this mitigation MUST add an additional input check to > any incoming segment. The ACK value is considered acceptable only if > it is in the range of ((SND.UNA - MAX.SND.WND) <= SEG.ACK <= > SND.NXT). All incoming segments whose ACK value doesn't satisfy the > above condition MUST be discarded and an ACK sent back. > > Move tcp_send_challenge_ack() before tcp_ack() to avoid a forward > declaration. > > Signed-off-by: Eric Dumazet Applied.