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,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 38FACC43142 for ; Tue, 26 Jun 2018 15:00:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F299226CB7 for ; Tue, 26 Jun 2018 15:00:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F299226CB7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.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 S1751897AbeFZPAc (ORCPT ); Tue, 26 Jun 2018 11:00:32 -0400 Received: from mga01.intel.com ([192.55.52.88]:38081 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751796AbeFZPA2 (ORCPT ); Tue, 26 Jun 2018 11:00:28 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 26 Jun 2018 08:00:28 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.51,274,1526367600"; d="scan'208";a="60298635" Received: from 2b52.sc.intel.com ([143.183.136.147]) by FMSMGA003.fm.intel.com with ESMTP; 26 Jun 2018 08:00:28 -0700 Message-ID: <1530025017.27091.1.camel@intel.com> Subject: Re: [PATCH 00/10] Control Flow Enforcement - Part (3) From: Yu-cheng Yu To: Andy Lutomirski , Linux API , Jann Horn , Florian Weimer Cc: LKML , linux-doc@vger.kernel.org, Linux-MM , linux-arch , X86 ML , "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , "H. J. Lu" , "Shanbhogue, Vedvyas" , "Ravi V. Shankar" , Dave Hansen , Jonathan Corbet , Oleg Nesterov , Arnd Bergmann , mike.kravetz@oracle.com Date: Tue, 26 Jun 2018 07:56:57 -0700 In-Reply-To: References: <20180607143807.3611-1-yu-cheng.yu@intel.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.18.5.2-0ubuntu3.2 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2018-06-25 at 22:26 -0700, Andy Lutomirski wrote: > On Thu, Jun 7, 2018 at 7:41 AM Yu-cheng Yu > wrote: > > > > > > This series introduces CET - Shadow stack > I think you should add some mitigation against sigreturn-oriented > programming.  How about creating some special token on the shadow > stack that indicates the presence of a signal frame at a particular > address when delivering a signal and verifying and popping that token > in sigreturn?  The token could be literally the address of the signal > frame, and you could make this unambiguous by failing sigreturn if > CET > is on and the signal frame is in executable memory. > > IOW, it would be a shame if sigreturn() itself became a convenient > CET-bypassing gadget. > > --Andy I will look into that. Thanks, Yu-cheng