From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3DA90C43381 for ; Tue, 26 Feb 2019 17:13:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1670921848 for ; Tue, 26 Feb 2019 17:13:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727998AbfBZRNZ (ORCPT ); Tue, 26 Feb 2019 12:13:25 -0500 Received: from shards.monkeyblade.net ([23.128.96.9]:57268 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727196AbfBZRNZ (ORCPT ); Tue, 26 Feb 2019 12:13:25 -0500 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::bf5]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 0896114F1DCD4; Tue, 26 Feb 2019 09:13:25 -0800 (PST) Date: Tue, 26 Feb 2019 09:13:24 -0800 (PST) Message-Id: <20190226.091324.1656342529138987636.davem@davemloft.net> To: michael.chan@broadcom.com Cc: maheshb@google.com, edumazet@google.com, dja@axrens.net, netdev@vger.kernel.org Subject: Re: [PATCH RFC] net: Validate size of non-TSO packets in validate_xmit_skb(). From: David Miller In-Reply-To: <1551178601-16564-1-git-send-email-michael.chan@broadcom.com> References: <1551178601-16564-1-git-send-email-michael.chan@broadcom.com> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Tue, 26 Feb 2019 09:13:25 -0800 (PST) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Michael Chan Date: Tue, 26 Feb 2019 05:56:41 -0500 > There have been reports of oversize UDP packets being sent to the > driver to be transmitted, causing error conditions. The issue is > likely caused by the dst of the SKB switching between 'lo' with > 64K MTU and the hardware device with a smaller MTU. Patches are > being proposed by Mahesh Bandewar to fix the > issue. > > Separately, we should add a length check in validate_xmit_skb() > to drop these oversize packets before they reach the driver. > This patch only validates non-TSO packets. Complete validation > of segmented TSO packet size will probably be too slow. > > Signed-off-by: Michael Chan Anything which changes the dst of an SKB really is responsible for fixing up whatever became "incompatible" in the new path. So like Eric I want to see this out of the fast path.