Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754909AbbGUUVb (ORCPT ); Tue, 21 Jul 2015 16:21:31 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:35623 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751743AbbGUUV3 (ORCPT ); Tue, 21 Jul 2015 16:21:29 -0400 Message-ID: <55AEA99C.3030608@oracle.com> Date: Tue, 21 Jul 2015 16:20:44 -0400 From: Sasha Levin User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Andy Lutomirski , Peter Zijlstra , Steven Rostedt CC: "security@kernel.org" , X86 ML , Borislav Petkov , linux-kernel@vger.kernel.org, Konrad Rzeszutek Wilk , Boris Ostrovsky Subject: Re: [PATCH v2 2/3] x86/ldt: Make modify_ldt optional References: <06f4a63325ac221868770a8d63207d74b160df89.1437508486.git.luto@kernel.org> In-Reply-To: <06f4a63325ac221868770a8d63207d74b160df89.1437508486.git.luto@kernel.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Source-IP: userv0021.oracle.com [156.151.31.71] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 607 Lines: 19 On 07/21/2015 03:59 PM, Andy Lutomirski wrote: > The modify_ldt syscall exposes a large attack surface and is > unnecessary for modern userspace. Make it optional. Since this a "default y" option I think we need to make the implications of this a bit clearer. Do we know what userspace would break? Maybe add a WARN_ONCE() in a stub syscall? Thanks, Sasha -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/