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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT autolearn=unavailable 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 0074AC43381 for ; Fri, 8 Mar 2019 15:50:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C513B2087C for ; Fri, 8 Mar 2019 15:50:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726442AbfCHPu4 (ORCPT ); Fri, 8 Mar 2019 10:50:56 -0500 Received: from mail.us.es ([193.147.175.20]:51106 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726429AbfCHPuz (ORCPT ); Fri, 8 Mar 2019 10:50:55 -0500 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id B7CEE5E5399 for ; Fri, 8 Mar 2019 16:50:51 +0100 (CET) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id A74C6DA87D for ; Fri, 8 Mar 2019 16:50:51 +0100 (CET) Received: by antivirus1-rhel7.int (Postfix, from userid 99) id 9947DDA87A; Fri, 8 Mar 2019 16:50:51 +0100 (CET) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id B24F4DA796; Fri, 8 Mar 2019 16:50:49 +0100 (CET) Received: from 192.168.1.97 (192.168.1.97) by antivirus1-rhel7.int (F-Secure/fsigk_smtp/550/antivirus1-rhel7.int); Fri, 08 Mar 2019 16:50:49 +0100 (CET) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/antivirus1-rhel7.int) Received: from us.es (sys.soleta.eu [212.170.55.40]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: 1984lsi) by entrada.int (Postfix) with ESMTPSA id 8DB144265A2F; Fri, 8 Mar 2019 16:50:49 +0100 (CET) Date: Fri, 8 Mar 2019 16:50:49 +0100 X-SMTPAUTHUS: auth mail.us.es From: Pablo Neira Ayuso To: Xin Long Cc: network dev , netfilter-devel@vger.kernel.org, Marcelo Ricardo Leitner , Neil Horman Subject: Re: [PATCH net] netfilter: set skb transport_header before calling sctp_compute_cksum Message-ID: <20190308155049.by7f4uzjxqnf3xu7@salvia> References: <740683890e28e93c1b2e940a28089ca10f006b7f.1551601041.git.lucien.xin@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <740683890e28e93c1b2e940a28089ca10f006b7f.1551601041.git.lucien.xin@gmail.com> User-Agent: NeoMutt/20170113 (1.7.2) X-Virus-Scanned: ClamAV using ClamSMTP Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org Hi, On Sun, Mar 03, 2019 at 04:17:21PM +0800, Xin Long wrote: > sctp_hdr(skb) only works when skb->transport_header is set > properly. > > But in the path of nf_conntrack_in: > > sctp_packet() -> sctp_error() -> sctp_compute_cksum(). > > skb->transport_header is not guaranteed to be right value > for sctp. It will cause to fail to check the checksum for > sctp packets. > > So fix it by setting skb transport_header before calling > sctp_compute_cksum(). I see a few more calls to sctp_compute_cksum() in the netfilter tree. I guess they are broken too. In netfilter, skb->transport_header is never set from the input path, I think this introduces an assymmetry with other transport protocols. May we have a variant of sctp_compute_cksum() which does not rely on sctp_hdr() instead?