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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 B7E15C43441 for ; Mon, 26 Nov 2018 19:50:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 66ABD20C01 for ; Mon, 26 Nov 2018 19:50:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 66ABD20C01 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=zytor.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 S1726743AbeK0Gp3 (ORCPT ); Tue, 27 Nov 2018 01:45:29 -0500 Received: from terminus.zytor.com ([198.137.202.136]:34009 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726253AbeK0Gp2 (ORCPT ); Tue, 27 Nov 2018 01:45:28 -0500 Received: from carbon-x1.hos.anvin.org (c-24-5-245-234.hsd1.ca.comcast.net [24.5.245.234] (may be forged)) (authenticated bits=0) by mail.zytor.com (8.15.2/8.15.2) with ESMTPSA id wAQJngPC1524699 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NO); Mon, 26 Nov 2018 11:49:42 -0800 Subject: Re: [PATCH] x86/fpu: XRSTOR is expected to raise #GP To: Sebastian Andrzej Siewior , Jann Horn Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Andy Lutomirski , kernel-hardening@lists.openwall.com, "Naveen N. Rao" , linux-kernel@vger.kernel.org, x86@kernel.org References: <20181126172706.184008-1-jannh@google.com> <20181126174945.r2ubrlg2gzwog2ez@linutronix.de> From: "H. Peter Anvin" Message-ID: <4d4c4f1f-72e3-0182-151e-8bd455ccd143@zytor.com> Date: Mon, 26 Nov 2018 11:49:37 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.0 MIME-Version: 1.0 In-Reply-To: <20181126174945.r2ubrlg2gzwog2ez@linutronix.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/26/18 9:49 AM, Sebastian Andrzej Siewior wrote: > On 2018-11-26 18:27:06 [+0100], Jann Horn wrote: >> commit 75045f77f7a7 ("x86/extable: Introduce _ASM_EXTABLE_UA for uaccess >> fixups") incorrectly replaced the fixup entry for XSTATE_OP with a >> user-#PF-only fixup. However, XRSTOR can also raise #GP when the supplied >> address points to userspace memory. Change it back. > > The #GP is raised if the xstate content is invalid. But I guess the > details don't matter. > >> Reported-by: Sebastian Andrzej Siewior >> Fixes: 75045f77f7a7 ("x86/extable: Introduce _ASM_EXTABLE_UA for uaccess fixups") >> Signed-off-by: Jann Horn > Acked-by: Sebastian Andrzej Siewior > It does matter -- please correct the patch description, or we might have some serious confusion at some arbitrary point in the future with the result that the bug gets re-introduced; it would not be the first time. -hpa