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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 0B09CC3279B for ; Mon, 2 Jul 2018 22:23:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B13D124C7D for ; Mon, 2 Jul 2018 22:23:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B13D124C7D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753615AbeGBWXs (ORCPT ); Mon, 2 Jul 2018 18:23:48 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:40940 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753312AbeGBWXq (ORCPT ); Mon, 2 Jul 2018 18:23:46 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5D26B401C96A; Mon, 2 Jul 2018 22:23:46 +0000 (UTC) Received: from crecklin.bos.csb (ovpn-120-13.rdu2.redhat.com [10.10.120.13]) by smtp.corp.redhat.com (Postfix) with ESMTP id 351F82026D76; Mon, 2 Jul 2018 22:23:45 +0000 (UTC) Reply-To: crecklin@redhat.com Subject: Re: [PATCH v3] add param that allows bootline control of hardened usercopy To: Kees Cook Cc: Laura Abbott , Paolo Abeni , LKML , Linux-MM , Kernel Hardening , Josh Poimboeuf , Peter Zijlstra References: <1530101255-13988-1-git-send-email-crecklin@redhat.com> <5506a72f-99ac-b47c-4ace-86c43b17b5c5@redhat.com> <0076b929-4785-0665-0e08-789c504f6b78@redhat.com> From: Christoph von Recklinghausen Organization: Red Hat Message-ID: <5f21bb3c-0165-38d1-b68b-96d53c2b70f4@redhat.com> Date: Mon, 2 Jul 2018 18:23:44 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Mon, 02 Jul 2018 22:23:46 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Mon, 02 Jul 2018 22:23:46 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'crecklin@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/02/2018 04:54 PM, Kees Cook wrote: > On Mon, Jul 2, 2018 at 11:55 AM, Christoph von Recklinghausen > wrote: >> On 07/02/2018 02:43 PM, Kees Cook wrote: >>> On Sat, Jun 30, 2018 at 1:43 PM, Christoph von Recklinghausen >>> wrote: >>>> The last issue I'm chasing is build failures on ARCH=m68k. The error is >>>> atomic_read and friends needed by the jump label code not being found. >>>> The config has CONFIG_BROKEN_ON_SMP=y, so the jump label calls I added >>>> will only be made #ifndef CONFIG_BROKEN_ON_SMP. Do you think that's >>>> worth a mention in the blurb that's added to >>>> Documentation/admin-guide/kernel-parameters.txt? >>> Uhm, that's weird -- I think the configs on m68k need fixing then? I >>> don't want to have to sprinkle that ifdef in generic code. >>> >>> How are other users of static keys and jump labels dealing with m68k weirdness? >>> >> There's also CONFIG_JUMP_LABEL which is defined in x86_64 but not >> defined in the m68k configs. I'll use that instead. In hindsight I >> should have spotted that but didn't. > I think what I mean is that jump labels should always work. There > shouldn't be a need to #ifdef the common usercopy code. i.e. > include/linux/jump_label.h should work on all architectures already. I > see HAVE_JUMP_LABEL tests there, for example: > > #if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL) > # define HAVE_JUMP_LABEL > #endif > > Other core code uses static keys without this; what is the failing combination? The complaints were when there was jump_label code in include/linux/thread_info.h. Now that the code is isolated to mm/usercopy.c, it successfully builds for m68k with mention of CONFIG_JUMP_LABEL and CONFIG_SMP_BROKEN removed. I'll send out a new patch in the morning after I test some more. Thanks, Chris > -Kees >