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 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by aws-us-west-2-korg-lkml-1.web.codeaurora.org (Postfix) with ESMTP id 86F3FC07D5C for ; Thu, 14 Jun 2018 14:59:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 43564208E8 for ; Thu, 14 Jun 2018 14:59:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 43564208E8 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 S936164AbeFNO7d (ORCPT ); Thu, 14 Jun 2018 10:59:33 -0400 Received: from mga02.intel.com ([134.134.136.20]:58592 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754907AbeFNO73 (ORCPT ); Thu, 14 Jun 2018 10:59:29 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 14 Jun 2018 07:59:28 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.51,222,1526367600"; d="scan'208";a="57362096" Received: from 2b52.sc.intel.com (HELO [143.183.136.147]) ([143.183.136.147]) by fmsmga002.fm.intel.com with ESMTP; 14 Jun 2018 07:59:27 -0700 Message-ID: <1528988176.13101.15.camel@2b52.sc.intel.com> Subject: Re: [PATCH 00/10] Control Flow Enforcement - Part (3) From: Yu-cheng Yu To: Balbir Singh Cc: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , "H.J. Lu" , Vedvyas Shanbhogue , "Ravi V. Shankar" , Dave Hansen , Andy Lutomirski , Jonathan Corbet , Oleg Nesterov , Arnd Bergmann , Mike Kravetz Date: Thu, 14 Jun 2018 07:56:16 -0700 In-Reply-To: <814fc15e80908d8630ff665be690ccbe6e69be88.camel@gmail.com> References: <20180607143807.3611-1-yu-cheng.yu@intel.com> <1528815820.8271.16.camel@2b52.sc.intel.com> <814fc15e80908d8630ff665be690ccbe6e69be88.camel@gmail.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4-0ubuntu2 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2018-06-14 at 11:07 +1000, Balbir Singh wrote: > On Tue, 2018-06-12 at 08:03 -0700, Yu-cheng Yu wrote: > > On Tue, 2018-06-12 at 20:56 +1000, Balbir Singh wrote: > > > > > > On 08/06/18 00:37, Yu-cheng Yu wrote: > > > > This series introduces CET - Shadow stack > > > > > > > > At the high level, shadow stack is: > > > > > > > > Allocated from a task's address space with vm_flags VM_SHSTK; > > > > Its PTEs must be read-only and dirty; > > > > Fixed sized, but the default size can be changed by sys admin. > > > > > > > > For a forked child, the shadow stack is duplicated when the next > > > > shadow stack access takes place. > > > > > > > > For a pthread child, a new shadow stack is allocated. > > > > > > > > The signal handler uses the same shadow stack as the main program. > > > > > > > > > > Even with sigaltstack()? > > > > > Yes. > > I am not convinced that it would work, as we switch stacks, oveflow might > be an issue. I also forgot to bring up setcontext(2), I presume those > will get new shadow stacks Do you mean signal stack/sigaltstack overflow or swapcontext in a signal handler? Yu-cheng