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=-3.6 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,SPF_HELO_NONE, SPF_PASS autolearn=no 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 69965C2D0EF for ; Mon, 30 Mar 2020 16:11:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 40E942072E for ; Mon, 30 Mar 2020 16:11:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Fsf0vB9X" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730147AbgC3QLV (ORCPT ); Mon, 30 Mar 2020 12:11:21 -0400 Received: from mail-wm1-f65.google.com ([209.85.128.65]:54568 "EHLO mail-wm1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726085AbgC3QLU (ORCPT ); Mon, 30 Mar 2020 12:11:20 -0400 Received: by mail-wm1-f65.google.com with SMTP id c81so20544921wmd.4 for ; Mon, 30 Mar 2020 09:11:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=wuIL3dpgBGs3RFudv7zV0iYRJt82al6XSb3+T17EDpk=; b=Fsf0vB9XtMer+vnYhWTjCr0ij5HefSSwzYRAq9HrkPpYd5OsFPAWabbBkyAWW/EOG+ xOpF2Fs7cS1/oz2kE/44IFSaNI/+kO+VK7ARYYL3cGAHF/vRakQ25nYAcB3u7477qqTU NjciCEnQNh67vY35nwmqkCUnrwB+SJ2dURem+NQOStVfQO3T9a7lPgrCiCVv/npemKoI ltwkk5D0Zp9vpQyxRueDGD4fUZyXlIzWti7kHaxiK9/V5vdCspJO2e+kx7fXyqzl0bfE S6qughigq2cfn8PR4EouDn9U+jid+jQmMQuOjPL7N6XlRMHxF5TBXPorl9pnafHPSjmE STnA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=wuIL3dpgBGs3RFudv7zV0iYRJt82al6XSb3+T17EDpk=; b=HphdmI3mYbx3GZk1HsYRDq5qycesG5S4bkUoVBMo11wovuh5zeMKlT1MI+1w476AvC +tGU9MrLD807518JIKTVOieEOPhW/ZZGZKnWu2vk3s0xXcwbjsDkkLqRHxQ3JBn1Ld0Q GCvcl8hGvzvWcs4SPIQ/gHhoTIHLhIKBV/dHEosy2CNZ7DfWkKlV6yu+C5Yj1fzF4wkQ M4iTGhVL69a8u9Bc0fkk+cy2OpEwAiwT9dPsJGqCLTXvGIgQmBER5WPhehgBROr4KUSm Nep1RPd8ACVCXGlIrWpRbwFupUE6DHj0Cf3yXpzyDh9C7qLzDa1AtT6KA8mosIhpnBov yfgw== X-Gm-Message-State: ANhLgQ1cKQrPG2nnHQM1xHSipZUKzm+9Ej8XNOA3MXl47xkvIpGkuMZ3 ycDi0LGxLQNp6o2uIb5/gVbauid6kE4TcscTXWwfo/Wu X-Google-Smtp-Source: ADFU+vviJiDSZQTm6KccRRWaWn+NFgNNGvl5N57yByI6bXbAH5JQrfERFXR+2quIuEnSlEEdYDQr67cspQgQtE/8LXw= X-Received: by 2002:a7b:cde8:: with SMTP id p8mr24762wmj.87.1585584678509; Mon, 30 Mar 2020 09:11:18 -0700 (PDT) MIME-Version: 1.0 References: <20200330132759.GA31510@strlen.de> In-Reply-To: <20200330132759.GA31510@strlen.de> From: Xin Long Date: Tue, 31 Mar 2020 00:14:46 +0800 Message-ID: Subject: Re: [PATCH net] udp: fix a skb extensions leak To: Florian Westphal Cc: network dev , davem , Paolo Abeni , Steffen Klassert Content-Type: text/plain; charset="UTF-8" Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Mar 30, 2020 at 9:28 PM Florian Westphal wrote: > > Xin Long wrote: > > On udp rx path udp_rcv_segment() may do segment where the frag skbs > > will get the header copied from the head skb in skb_segment_list() > > by calling __copy_skb_header(), which could overwrite the frag skbs' > > extensions by __skb_ext_copy() and cause a leak. > > > > This issue was found after loading esp_offload where a sec path ext > > is set in the skb. > > > > On udp tx gso path, it works well as the frag skbs' extensions are > > not set. So this issue should be fixed on udp's rx path only and > > release the frag skbs' extensions before going to do segment. > > Reported-by: Xiumei Mu > > Fixes: cf329aa42b66 ("udp: cope with UDP GRO packet misdirection") > > Hmm, I suspect this bug came in via > 3a1296a38d0cf62bffb9a03c585cbd5dbf15d596 , net: Support GRO/GSO fraglist chaining. > > I suspect correct fix is: > > diff --git a/net/core/skbuff.c b/net/core/skbuff.c > index 621b4479fee1..7e29590482ce 100644 > --- a/net/core/skbuff.c > +++ b/net/core/skbuff.c > @@ -3668,6 +3668,7 @@ struct sk_buff *skb_segment_list(struct sk_buff *skb, > > skb_push(nskb, -skb_network_offset(nskb) + offset); > > + skb_release_head_state(nskb); > __copy_skb_header(nskb, skb); > > skb_headers_offset_update(nskb, skb_headroom(nskb) - skb_headroom(skb)); > > AFAICS we not only leak reference of extensions, but also skb->dst and skb->_nfct. Works for this issue. Tested-by: Xin Long