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=-1.0 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 39578C4360F for ; Thu, 4 Apr 2019 21:40:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E922920882 for ; Thu, 4 Apr 2019 21:40:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=networkplumber-org.20150623.gappssmtp.com header.i=@networkplumber-org.20150623.gappssmtp.com header.b="0u4MLXJf" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728888AbfDDVkL (ORCPT ); Thu, 4 Apr 2019 17:40:11 -0400 Received: from mail-pf1-f194.google.com ([209.85.210.194]:40732 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726418AbfDDVkL (ORCPT ); Thu, 4 Apr 2019 17:40:11 -0400 Received: by mail-pf1-f194.google.com with SMTP id c207so2023328pfc.7 for ; Thu, 04 Apr 2019 14:40:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=LmzORkHaNY4xtWNzXV2yL0djjyADwevz4fZP3btn25k=; b=0u4MLXJfW6GYw5z+Q6+SdbhLoDQpHA/eOm8cvK1OGEdf484+04/UqOH8lvPT5McHOF sY3C9ECgvbsrL+RaHxIs3rfuxQFik53Suo9nsQFUXylhKyCIHvW4hZxmdO3x8myvZZ8c KWxLPdwYC83UPZC2kbQ9ojv/F/xmzkL98hk7GV1bB6OXL+5X2DvvmIdlJB8jmZcV4mWN ZFsNDjjuUoUGOXBVeObTxYEpKEq9iLuk1rZJxHYUMQ7kJEEr4XhuVS2TTTxc3XAknFlt vZpovPS34qkQTHkM8fSwlgkBy6xCkXMtgXRFYesFaL9ns1jpK+z4FWDAlkp+9YPRpCmj M4aw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=LmzORkHaNY4xtWNzXV2yL0djjyADwevz4fZP3btn25k=; b=n7uVwl5GylXOrkX/2mHe1aYwMm3lmu8RPGdtm6sYYHTdXA+Vqjp/QmKZvdSIgpo6G+ iBBV2tEA4DIiXDyrZg6jM8G/J1lanypEE1S6nLKAAiuOqAHOhIb4bz1NYcRnbXG+mjdi itP4mbhw+oHvG270sc9SpvGCY2h+5G82dOGjXhiFXxfc65bQo/ROMdNNcfTNmQ1aAwY1 sjt//HaqFgYm+eja6vsckKz9WcsNX0/btM1zHFnMJCaHPwl1AJqr6gGtiygL/JH1lnQk nowdlE2seu/6Eqi0YAHZFqvnJD4j1IO9auLh/qHhOK4ocCANe8BR0ZanXTTslGXK5RI/ zofw== X-Gm-Message-State: APjAAAXZhXgBZ4Z30PO3+NiQpOsqlRjssdWTGcPwGDPvyJleL1GrTXFL aP9Yh/HaumxCQpqFQZT+jbSK9Q== X-Google-Smtp-Source: APXvYqzO8LHxNpPt/zpqJkjiJE7lGt0ELJrrAf9WSu6L5P8xa+1QvVueCezbNDOU2lplkJvX3gHa5g== X-Received: by 2002:a63:3f8d:: with SMTP id m135mr7840532pga.228.1554414010497; Thu, 04 Apr 2019 14:40:10 -0700 (PDT) Received: from shemminger-XPS-13-9360 ([167.220.102.127]) by smtp.gmail.com with ESMTPSA id d68sm11306202pfg.16.2019.04.04.14.40.10 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 04 Apr 2019 14:40:10 -0700 (PDT) Date: Thu, 4 Apr 2019 14:40:07 -0700 From: Stephen Hemminger To: Toke =?UTF-8?B?SMO4aWxhbmQtSsO4cmdlbnNlbg==?= Cc: David Miller , netdev@vger.kernel.org, cake@lists.bufferbloat.net Subject: Re: [PATCH net 2/2] sch_cake: Make sure we can write the IP header before changing DSCP bits Message-ID: <20190404144007.7ac9bfe0@shemminger-XPS-13-9360> In-Reply-To: <87y34p1owe.fsf@toke.dk> References: <155438289359.18760.18027832614176337074.stgit@alrua-x1> <155438289374.18760.4278774647362746152.stgit@alrua-x1> <20190404123536.3c966937@shemminger-XPS-13-9360> <87y34p1owe.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, 04 Apr 2019 22:44:33 +0200 Toke H=C3=B8iland-J=C3=B8rgensen wrote: > Stephen Hemminger writes: >=20 > > On Thu, 04 Apr 2019 15:01:33 +0200 > > Toke H=C3=B8iland-J=C3=B8rgensen wrote: > > =20 > >> static u8 cake_handle_diffserv(struct sk_buff *skb, u16 wash) > >> { > >> + int wlen =3D skb_network_offset(skb); =20 > > > > In theory this could be negative, you should handle that? > > Rather than calling may_pull() with a huge unsigned value. =20 >=20 > Huh, that would imply that skb->network_header points to before > skb->head; when does that happen? >=20 > Also, pskb_may_pull() does check for len > skb->len, so I guess a > follow-up question would be, "does it happen often enough to warrant > handling at this level"? >=20 > Also, I copied that bit from sch_dsmark, so if you really thing it needs > to be fixed, I guess we should fix both... >=20 > -Toke It should never happen just paranoid