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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 1B482C3F2D7 for ; Wed, 4 Mar 2020 18:21:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E7B072146E for ; Wed, 4 Mar 2020 18:21:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="EtH+RNLz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730098AbgCDSVv (ORCPT ); Wed, 4 Mar 2020 13:21:51 -0500 Received: from mail-pf1-f196.google.com ([209.85.210.196]:42473 "EHLO mail-pf1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730032AbgCDSVv (ORCPT ); Wed, 4 Mar 2020 13:21:51 -0500 Received: by mail-pf1-f196.google.com with SMTP id f5so1359833pfk.9 for ; Wed, 04 Mar 2020 10:21:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=xF2I7tf+DwxpQhNciBVkWhhaWOLjPvYzGL3E90sj2so=; b=EtH+RNLzhqY+QqYdV6X7ap6Xu3EpSaat18+ckZb/mOfySU0ooqa/9cKD/lI/wgqztb ZK2Ma6j1qv5DcakHHIlnNCH8JvP6u0Ga6Lxhnp2OX/arBJTY2+8pgH3SNyBm7i2VIJ2k nN0QThNn3RyhAFc+q1sXxzjkc/ZdjOgh2+oOU= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=xF2I7tf+DwxpQhNciBVkWhhaWOLjPvYzGL3E90sj2so=; b=uDu4MwZIy1ZQga8/7PS1cnkMrLSxALQyry1Jq8YZ1Ca7yLeOop2JWEq5RHlncYavg5 kNDd5X4gsXwIIOvrGdxyQiyyjw8q6v31WoTTpMrhIYRaMLJEN3QDfmLC7Dn/hIvRrfjf jqeiAfRZMYijz7N6iD0JcquKrs5yXPExIQPuwIzBfw4UotFnBBebllynestQk5+/QcBK JikfGLiAauSeAP0+QYc22vseJuBtMnCMDdMqIZVsNhBqhibHfYBqvMAR1PbeFYIZFF4o qB7W4rYupoMV9zcXCjW4iExI2VKM1FGZgNZ2dKJTLpnhYkAlYk4VHdubgg0/ZmoslqZR A20Q== X-Gm-Message-State: ANhLgQ0WTYTkE1l6JJJizVl1hcjRJ/E139iqy7OSbSlpSKLJlPOYW2R1 l119VEoLTu47rLqknFBWRuOvSQ== X-Google-Smtp-Source: ADFU+vuGalFADUNS2CsAir9E+YeLAVnzSZsmifwLoGDru8DbnpAUozLyZDUnqEqdqAQL4AUGpiCQNw== X-Received: by 2002:a63:ed14:: with SMTP id d20mr3606078pgi.267.1583346110401; Wed, 04 Mar 2020 10:21:50 -0800 (PST) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id m59sm3603815pjb.41.2020.03.04.10.21.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 04 Mar 2020 10:21:49 -0800 (PST) Date: Wed, 4 Mar 2020 10:21:48 -0800 From: Kees Cook To: Peter Zijlstra Cc: Kristen Carlson Accardi , Thomas Garnier , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Kernel Hardening , Herbert Xu , "David S. Miller" , "H. Peter Anvin" , the arch/x86 maintainers , Andy Lutomirski , Juergen Gross , Thomas Hellstrom , "VMware, Inc." , "Rafael J. Wysocki" , Len Brown , Pavel Machek , Rasmus Villemoes , Miguel Ojeda , Will Deacon , Ard Biesheuvel , Masami Hiramatsu , Jiri Slaby , Boris Ostrovsky , Josh Poimboeuf , Cao jin , Allison Randal , Linux Crypto Mailing List , LKML , virtualization@lists.linux-foundation.org, Linux PM list Subject: Re: [PATCH v11 00/11] x86: PIE support to extend KASLR randomization Message-ID: <202003041019.C6386B2F7@keescook> References: <20200228000105.165012-1-thgarnie@chromium.org> <202003022100.54CEEE60F@keescook> <20200303095514.GA2596@hirez.programming.kicks-ass.net> <6e7e4191612460ba96567c16b4171f2d2f91b296.camel@linux.intel.com> <202003031314.1AFFC0E@keescook> <20200304092136.GI2596@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200304092136.GI2596@hirez.programming.kicks-ass.net> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 04, 2020 at 10:21:36AM +0100, Peter Zijlstra wrote: > But at what cost; it does unspeakable ugly to the asm. And didn't a > kernel compiled with the extended PIE range produce a measurably slower > kernel due to all the ugly? Was that true? I thought the final results were a wash and that earlier benchmarks weren't accurate for some reason? I can't find the thread now. Thomas, do you have numbers on that? BTW, I totally agree that fgkaslr is the way to go in the future. I am mostly arguing for this under the assumption that it doesn't have meaningful performance impact and that it gains the kernel some flexibility in the kinds of things it can do in the future. If the former is not true, then I'd agree, the benefit needs to be more clear. -- Kees Cook