From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH 0/2] ppp: mppe: fixes MPPE desync on links which don't guarantee packet ordering Date: Sun, 26 Apr 2015 23:26:16 -0400 (EDT) Message-ID: <20150426.232616.353503560380309931.davem@davemloft.net> References: <1430073653-22131-1-git-send-email-sylvain.rochet@finsecur.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: paulus@samba.org, linux-ppp@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: sylvain.rochet@finsecur.com Return-path: In-Reply-To: <1430073653-22131-1-git-send-email-sylvain.rochet@finsecur.com> Sender: linux-ppp-owner@vger.kernel.org List-Id: netdev.vger.kernel.org From: Sylvain Rochet Date: Sun, 26 Apr 2015 20:40:51 +0200 > I am currently having an issue with PPP over L2TP (UDP) and MPPE in > stateless mode (default mode), UDP does not guarantee packet ordering so > we might get out of order packet. MPPE needs to be continuously synched > so we should drop late UDP packet. > > I added a printk on the number of time we rekeyed in MPPE decompressor, > this is what we currently have if we receive a slightly out of order UDP > packet: ... > This is obviously wrong, we missed packet 1561 and we already rekeyed 2 > times for 1562 we previously received, we can't recover the decryption > key we need for 1561, we should drop it instead of rekeying 4095 times. > > This patch series drop any packet with are not within the 4096/2 forward > window. Series applied, thanks Sylvain.