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=-10.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 7E3F0C2BB84 for ; Mon, 7 Sep 2020 09:43:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 34D8520C09 for ; Mon, 7 Sep 2020 09:43:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728396AbgIGJnU (ORCPT ); Mon, 7 Sep 2020 05:43:20 -0400 Received: from a.mx.secunet.com ([62.96.220.36]:60318 "EHLO a.mx.secunet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726301AbgIGJnT (ORCPT ); Mon, 7 Sep 2020 05:43:19 -0400 Received: from localhost (localhost [127.0.0.1]) by a.mx.secunet.com (Postfix) with ESMTP id 368CF201CC; Mon, 7 Sep 2020 11:43:16 +0200 (CEST) X-Virus-Scanned: by secunet Received: from a.mx.secunet.com ([127.0.0.1]) by localhost (a.mx.secunet.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id DrTO_au6XWdt; Mon, 7 Sep 2020 11:43:15 +0200 (CEST) Received: from mail-essen-02.secunet.de (mail-essen-02.secunet.de [10.53.40.205]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by a.mx.secunet.com (Postfix) with ESMTPS id 65E4D2009B; Mon, 7 Sep 2020 11:43:15 +0200 (CEST) Received: from mbx-essen-01.secunet.de (10.53.40.197) by mail-essen-02.secunet.de (10.53.40.205) with Microsoft SMTP Server (TLS) id 14.3.487.0; Mon, 7 Sep 2020 11:43:15 +0200 Received: from gauss2.secunet.de (10.182.7.193) by mbx-essen-01.secunet.de (10.53.40.197) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2044.4; Mon, 7 Sep 2020 11:43:15 +0200 Received: by gauss2.secunet.de (Postfix, from userid 1000) id B50913180513; Mon, 7 Sep 2020 11:43:14 +0200 (CEST) Date: Mon, 7 Sep 2020 11:43:14 +0200 From: Steffen Klassert To: Dmitry Safonov CC: , Dmitry Safonov <0x7f454c46@gmail.com>, "David S. Miller" , Florian Westphal , Herbert Xu , Jakub Kicinski , Stephen Suryaputra , , "Johannes Berg" , Shuah Khan , Subject: Re: [PATCH v2 0/6] xfrm: Add compat layer Message-ID: <20200907094314.GI20687@gauss3.secunet.de> References: <20200826014949.644441-1-dima@arista.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20200826014949.644441-1-dima@arista.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-ClientProxiedBy: cas-essen-02.secunet.de (10.53.40.202) To mbx-essen-01.secunet.de (10.53.40.197) X-EXCLAIMER-MD-CONFIG: 2c86f778-e09b-4440-8b15-867914633a10 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 26, 2020 at 02:49:43AM +0100, Dmitry Safonov wrote: > Changes since v1: > - reworked patches set to use translator > - separated the compat layer into xfrm_compat.c, > compiled under XFRM_USER_COMPAT config > - 32-bit messages now being sent in frag_list (like wext-core does) > - instead of __packed add compat_u64 members in compat structures > - selftest reworked to kselftest lib API > - added netlink dump testing to the selftest > > XFRM is disabled for compatible users because of the UABI difference. > The difference is in structures paddings and in the result the size > of netlink messages differ. > > Possibility for compatible application to manage xfrm tunnels was > disabled by: the commmit 19d7df69fdb2 ("xfrm: Refuse to insert 32 bit > userspace socket policies on 64 bit systems") and the commit 74005991b78a > ("xfrm: Do not parse 32bits compiled xfrm netlink msg on 64bits host"). > > This is my second attempt to resolve the xfrm/compat problem by adding > the 64=>32 and 32=>64 bit translators those non-visibly to a user > provide translation between compatible user and kernel. > Previous attempt was to interrupt the message ABI according to a syscall > by xfrm_user, which resulted in over-complicated code [1]. > > Florian Westphal provided the idea of translator and some draft patches > in the discussion. In these patches, his idea is reused and some of his > initial code is also present. > > There were a couple of attempts to solve xfrm compat problem: > https://lkml.org/lkml/2017/1/20/733 > https://patchwork.ozlabs.org/patch/44600/ > http://netdev.vger.kernel.narkive.com/2Gesykj6/patch-net-next-xfrm-correctly-parse-netlink-msg-from-32bits-ip-command-on-64bits-host > > All the discussions end in the conclusion that xfrm should have a full > compatible layer to correctly work with 32-bit applications on 64-bit > kernels: > https://lkml.org/lkml/2017/1/23/413 > https://patchwork.ozlabs.org/patch/433279/ > > In some recent lkml discussion, Linus said that it's worth to fix this > problem and not giving people an excuse to stay on 32-bit kernel: > https://lkml.org/lkml/2018/2/13/752 > > There is also an selftest for ipsec tunnels. > It doesn't depend on any library and compat version can be easy > build with: make CFLAGS=-m32 net/ipsec > > Patches as a .git branch: > https://github.com/0x7f454c46/linux/tree/xfrm-compat-v2 > > [1]: https://lkml.kernel.org/r/20180726023144.31066-1-dima@arista.com Thanks for the patches, looks good! Please fix the issue reported from 'kernel test robot' and resend. Thanks!