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 9E940C3F2CE 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 67B742146E for ; Wed, 4 Mar 2020 18:21:53 +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 S1730032AbgCDSVw (ORCPT ); Wed, 4 Mar 2020 13:21:52 -0500 Received: from mail-pf1-f193.google.com ([209.85.210.193]:35926 "EHLO mail-pf1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730055AbgCDSVw (ORCPT ); Wed, 4 Mar 2020 13:21:52 -0500 Received: by mail-pf1-f193.google.com with SMTP id i13so1373648pfe.3 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=EiO4GMmc5HKjvL3p7b8oylgEok2B8ULU68VXbgKjkVMZ6Bpjil/b7LvnNe9Txn0n5j NHxzVSazFm8QImYwRsssVs4bEwwII05RBXr6RUkQV6T7cevBqHqrdZvGmJGFpoICq+Kv X5W55w7rlvjFQwE5b8OIoLIqSk3GyhVf0AQMHK4J8HzmWKHS9JghEvSnT9GDRQOsTGyF XvldrXu8LQ1On9dURYgFySN2oPYVNx6PmJv7bO8uhB66+3y7UTnsxUbSTw6XiyS6WNEb cQ5MAOomC8UV2i8TfSvAtWibxpE1N/HD0aGnGUmdZDHjHhElXW/6vrX7cOBWEwllYS+e ejBg== X-Gm-Message-State: ANhLgQ1JMSHkt0pqlAEYNb8jaM7RW/ExaeqyLVOX5i53OF1wfJ3qEnqX ESu1J0c3sGUfsesvNPFt0uhj1Q== 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-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@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