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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 7C001C2D0BE for ; Sat, 7 Dec 2019 16:41:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4B0AF24670 for ; Sat, 7 Dec 2019 16:41:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726473AbfLGQlR (ORCPT ); Sat, 7 Dec 2019 11:41:17 -0500 Received: from correo.us.es ([193.147.175.20]:40894 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726414AbfLGQlR (ORCPT ); Sat, 7 Dec 2019 11:41:17 -0500 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id 884C5DA85E for ; Sat, 7 Dec 2019 17:41:13 +0100 (CET) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 7BA66DA70A for ; Sat, 7 Dec 2019 17:41:13 +0100 (CET) Received: by antivirus1-rhel7.int (Postfix, from userid 99) id 5C855DA70F; Sat, 7 Dec 2019 17:41:13 +0100 (CET) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 1264CDA705; Sat, 7 Dec 2019 17:41:11 +0100 (CET) Received: from 192.168.1.97 (192.168.1.97) by antivirus1-rhel7.int (F-Secure/fsigk_smtp/550/antivirus1-rhel7.int); Sat, 07 Dec 2019 17:41:11 +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 A16F04265A5A; Sat, 7 Dec 2019 17:41:10 +0100 (CET) Date: Sat, 7 Dec 2019 17:41:11 +0100 X-SMTPAUTHUS: auth mail.us.es From: Pablo Neira Ayuso To: Geert Uytterhoeven Cc: Stephen Rothwell , David Miller , Networking , Linux Next Mailing List , Linux Kernel Mailing List , NetFilter , Jiri Pirko , Jozsef Kadlecsik , Florian Westphal Subject: Re: nf_flow on big-endian (was: Re: linux-next: build warning after merge of the net-next tree) Message-ID: <20191207164111.fpnpoipaiadaxyde@salvia> References: <20191121183404.6e183d06@canb.auug.org.au> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="wbq7vzsidly2hz2h" Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) X-Virus-Scanned: ClamAV using ClamSMTP Sender: linux-next-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-next@vger.kernel.org --wbq7vzsidly2hz2h Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Hi Geert, On Tue, Nov 26, 2019 at 12:06:03PM +0100, Geert Uytterhoeven wrote: > On Thu, Nov 21, 2019 at 8:36 AM Stephen Rothwell wrote: > > After merging the net-next tree, today's linux-next build (powerpc > > allyesconfig) produced this warning: > > > > net/netfilter/nf_flow_table_offload.c: In function 'nf_flow_rule_match': > > net/netfilter/nf_flow_table_offload.c:80:21: warning: unsigned conversion from 'int' to '__be16' {aka 'short unsigned int'} changes value from '327680' to '0' [-Woverflow] > > 80 | mask->tcp.flags = TCP_FLAG_RST | TCP_FLAG_FIN; > > | ^~~~~~~~~~~~ > > > > Introduced by commit > > > > c29f74e0df7a ("netfilter: nf_flow_table: hardware offload support") > > This is now upstream, and must be completely broken on big-endian > platforms. > > The other user of the flags field looks buggy, too > (net/core/flow_dissector.c:__skb_flow_dissect_tcp()[*]): > > key_tcp->flags = (*(__be16 *) &tcp_flag_word(th) & htons(0x0FFF)); > > Disclaimer: I'm not familiar with the code or protocol, so below are just > my gut feelings. > > struct flow_dissector_key_tcp { > __be16 flags; > }; > > Does this have to be __be16, i.e. does it go over the wire? > If not, this should probably be __u16, and set using > "be32_to_cpu(flags) >> 16"? > If yes, "cpu_to_be16(be32_to_cpu(flags) >> 16)"? > (Ugh, needs convenience macros) > > [*] ac4bb5de27010e41 ("net: flow_dissector: add support for dissection > of tcp flags") I'm attaching a tentative patch, please let me know this is fixing up this issue there. Thanks. --wbq7vzsidly2hz2h Content-Type: text/x-diff; charset=us-ascii Content-Disposition: attachment; filename="x.patch" diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h index b8c20e9f343e..30ad4e07ff52 100644 --- a/include/net/flow_dissector.h +++ b/include/net/flow_dissector.h @@ -189,10 +189,17 @@ struct flow_dissector_key_eth_addrs { /** * struct flow_dissector_key_tcp: - * @flags: flags + * @flags: TCP flags (16-bit, including the initial Data offset field bits) + * @word: Data offset + reserved bits + TCP flags + window */ struct flow_dissector_key_tcp { - __be16 flags; + union { + struct { + __be16 flags; + __be16 __pad; + }; + __be32 flag_word; + }; }; /** diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index ca871657a4c4..83af4633f306 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -756,7 +756,7 @@ __skb_flow_dissect_tcp(const struct sk_buff *skb, key_tcp = skb_flow_dissector_target(flow_dissector, FLOW_DISSECTOR_KEY_TCP, target_container); - key_tcp->flags = (*(__be16 *) &tcp_flag_word(th) & htons(0x0FFF)); + key_tcp->flag_word = tcp_flag_word(th); } static void diff --git a/net/netfilter/nf_flow_table_offload.c b/net/netfilter/nf_flow_table_offload.c index c94ebad78c5c..30205d57226d 100644 --- a/net/netfilter/nf_flow_table_offload.c +++ b/net/netfilter/nf_flow_table_offload.c @@ -87,8 +87,8 @@ static int nf_flow_rule_match(struct nf_flow_match *match, switch (tuple->l4proto) { case IPPROTO_TCP: - key->tcp.flags = 0; - mask->tcp.flags = TCP_FLAG_RST | TCP_FLAG_FIN; + key->tcp.flag_word = 0; + mask->tcp.flag_word = TCP_FLAG_RST | TCP_FLAG_FIN; match->dissector.used_keys |= BIT(FLOW_DISSECTOR_KEY_TCP); break; case IPPROTO_UDP: --wbq7vzsidly2hz2h--