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=-7.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,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 30C1CC43381 for ; Tue, 26 Feb 2019 15:16:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 01D292184D for ; Tue, 26 Feb 2019 15:16:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="HxAun2tk" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727148AbfBZPQZ (ORCPT ); Tue, 26 Feb 2019 10:16:25 -0500 Received: from mail-pf1-f195.google.com ([209.85.210.195]:33117 "EHLO mail-pf1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726222AbfBZPQZ (ORCPT ); Tue, 26 Feb 2019 10:16:25 -0500 Received: by mail-pf1-f195.google.com with SMTP id i19so6401956pfd.0 for ; Tue, 26 Feb 2019 07:16:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=nvmXG3WiT12W/WVZ+1yXcjDQaEvvs9F2oVUz2DKLt+w=; b=HxAun2tkO1bOn9rXrUk3IhuHcgJDuTOJCRKKkGrtFzlx+54XDkf02KQHswv5e0WYX1 f5COkkxCZD5pMhEM4O5G3bR8lLSFS0Z8fjO07Dv8722kWHsqy3EfRmaybx+HahHeiVlQ bAV8fZN73CjNAm+JePanJUDpt/u06NQDMWPmLizfoSl2ss4On6I3qlYcSw2iADpRTsN/ f5xzBrsl2lZ9z5hUkYpSFys0pwqLhURv7+P6HwFh+9NSKOOnpkisgj+ffq3BB77xSqQi /llA9nY+eHJYFMe3V9MEN2iAaxf2PVJYIROhC5z7RjFsDAzFB+Ftjn2WHfBbZLx10hvP EUKw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=nvmXG3WiT12W/WVZ+1yXcjDQaEvvs9F2oVUz2DKLt+w=; b=MynzOVk9ThZaa4Mb6XNNbj/NV7YXc8J8QoqHX3G/6t9An26IZlX99NfhWtugrB/GSz UiqfVsy2fA3fbYcClBDnKU2N/jvs0KLSV/izWjRibCtXzUGlSe7C3HZQZG0GlfAI9UEd 2afAZ60ltqKWTVOKGzZwz9tuOBEvVPUD0WOHNBIq5UR1P7R0oB7N3LYwi2tzC6Nn3+N2 rfH1tL/RMJlr8YlpIVsNOW4j+9TMkXKbhJQvM1IFQ22fOjAEp1ZM6vQ8LQpfyUH3rFm3 J53RLgAGvnVRJHQi3gXXg41g7pmoGF6uO54p83H+c/RBGApfMdDG2eW91ZsSsugMuPpm z3MQ== X-Gm-Message-State: AHQUAubGpV3L55DilbMqqc3QtpQwpKzZOCHd0kWqoQ6hPY1Ss9Wy+XrU L9/spkKzil0tLvQ8KmGz9m6qNXq5 X-Google-Smtp-Source: AHgI3IYu+k71Zi6bK7w+NQ6wrTdYbpxWW/yTURA+sEN76OAlD8pnXOYCofR6Y49vrGy+GOWM9AHVjQ== X-Received: by 2002:a63:4f61:: with SMTP id p33mr5066029pgl.303.1551194184005; Tue, 26 Feb 2019 07:16:24 -0800 (PST) Received: from [192.168.86.235] (c-73-241-150-70.hsd1.ca.comcast.net. [73.241.150.70]) by smtp.gmail.com with ESMTPSA id u28sm19665195pgn.32.2019.02.26.07.16.22 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 26 Feb 2019 07:16:23 -0800 (PST) Subject: Re: [PATCH RFC] net: Validate size of non-TSO packets in validate_xmit_skb(). To: Michael Chan , davem@davemloft.net, maheshb@google.com, edumazet@google.com Cc: dja@axrens.net, netdev@vger.kernel.org References: <1551178601-16564-1-git-send-email-michael.chan@broadcom.com> From: Eric Dumazet Message-ID: Date: Tue, 26 Feb 2019 07:16:22 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <1551178601-16564-1-git-send-email-michael.chan@broadcom.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 02/26/2019 02:56 AM, Michael Chan wrote: > 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. Why ? We keep adding checks in the 'fast path' and make slower and slower after each release. We need to fix the root cause really. > This patch only validates non-TSO packets. Complete validation > of segmented TSO packet size will probably be too slow. > > Signed-off-by: Michael Chan > --- > net/core/dev.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/net/core/dev.c b/net/core/dev.c > index 5d03889..50c5174 100644 > --- a/net/core/dev.c > +++ b/net/core/dev.c > @@ -3373,6 +3373,13 @@ static struct sk_buff *validate_xmit_skb(struct sk_buff *skb, struct net_device > } > } > > + if (!skb_is_gso(skb) && > + skb->len > (dev->mtu + dev->hard_header_len + VLAN_HLEN)) { > + net_warn_ratelimited("%s(): Dropping %d bytes oversize skb.\n", > + __func__, skb->len); > + goto out_kfree_skb; > + } > + > skb = validate_xmit_xfrm(skb, features, again); > > return skb; >