From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752430AbcFPGFr (ORCPT ); Thu, 16 Jun 2016 02:05:47 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:6643 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751162AbcFPGFp (ORCPT ); Thu, 16 Jun 2016 02:05:45 -0400 X-IBM-Helo: d06dlp02.portsmouth.uk.ibm.com X-IBM-MailFrom: heiko.carstens@de.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org Date: Thu, 16 Jun 2016 08:05:38 +0200 From: Heiko Carstens To: Andy Lutomirski Cc: "linux-kernel@vger.kernel.org" , x86@kernel.org, Borislav Petkov , Nadav Amit , Kees Cook , Brian Gerst , "kernel-hardening@lists.openwall.com" , Linus Torvalds , Josh Poimboeuf Subject: Re: [PATCH 00/13] Virtually mapped stacks with guard pages (x86, core) References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16061606-0016-0000-0000-000001F97269 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16061606-0017-0000-0000-000021F24AF2 Message-Id: <20160616060538.GA3923@osiris> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-06-16_02:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1606160072 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 15, 2016 at 05:28:22PM -0700, Andy Lutomirski wrote: > Since the dawn of time, a kernel stack overflow has been a real PITA > to debug, has caused nondeterministic crashes some time after the > actual overflow, and has generally been easy to exploit for root. > > With this series, arches can enable HAVE_ARCH_VMAP_STACK. Arches > that enable it (just x86 for now) get virtually mapped stacks with > guard pages. This causes reliable faults when the stack overflows. > > If the arch implements it well, we get a nice OOPS on stack overflow > (as opposed to panicing directly or otherwise exploding badly). On > x86, the OOPS is nice, has a usable call trace, and the overflowing > task is killed cleanly. Do you have numbers which reflect the performance impact of this change?