Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755546AbcLAKIW (ORCPT ); Thu, 1 Dec 2016 05:08:22 -0500 Received: from mail1.windriver.com ([147.11.146.13]:47972 "EHLO mail1.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751697AbcLAKIU (ORCPT ); Thu, 1 Dec 2016 05:08:20 -0500 Subject: Re: [PATCH net] tipc: check minimum bearer MTU To: Michal Kubecek References: <20161130095702.DD033A0F14@unicorn.suse.cz> <4a2da388-d798-11cf-bf2c-84207cae6159@windriver.com> <20161130132333.GD19119@unicorn.suse.cz> CC: Jon Maloy , "David S. Miller" , , , , Ben Hutchings , Qian Zhang From: Ying Xue Message-ID: <2993fe74-a4d3-55ea-c600-ade0f0ee3a02@windriver.com> Date: Thu, 1 Dec 2016 18:07:47 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: <20161130132333.GD19119@unicorn.suse.cz> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 817 Lines: 25 >> >> For UDP bearer, it seems insufficient for us to check MTU size only >> when UDP bearer is enabled. Meanwhile, we should update MTU size for >> UDP bearer with Path MTU discovery protocol once MTU size is changed >> after bearer is enabled. > > I should admit I'm not that familiar with tipc. Do you mean updating > b->mtu in response to PMTU updates of the route used for ub->ubsock? Yes. > The way I understand it, it would be certainly useful but it's not > directly related to the security issue this patch addresses as if there > are no updates, b->mtu cannot get too low and there is no risk of > a buffer overflow. In other words, reflecting PMTU updates is something > that can be IMHO left for later. > Agreed. Regards, Ying > Michal Kubecek >