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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 BF5A6C352A3 for ; Mon, 10 Feb 2020 16:36:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 915F120714 for ; Mon, 10 Feb 2020 16:36:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ng1G/VSw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728015AbgBJQgc (ORCPT ); Mon, 10 Feb 2020 11:36:32 -0500 Received: from mail-qt1-f195.google.com ([209.85.160.195]:46196 "EHLO mail-qt1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727840AbgBJQgc (ORCPT ); Mon, 10 Feb 2020 11:36:32 -0500 Received: by mail-qt1-f195.google.com with SMTP id e21so1572386qtp.13 for ; Mon, 10 Feb 2020 08:36:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:date:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=B82P8bR5ozDn3yo+U/Bu+4ns+QtyTtYccr3OgXM2Xto=; b=ng1G/VSw9LRJOGQ1b6uRbkUgf37UT3j939mOC/5gYT9UUEFV3K9QbsTejURWL01vLe rmgHOjhlMXui4fo07OLbG88qSfkSbXMR0ti2l9a/Zu8qAtzhImtWAFOm4E9VCIcyf3ft +8VvpSZ7CXcUx/r+OE8G14NpzjP8nvDqR49PbWCEPFRMxE6MejJOT4VGgxdq5qSY31cL Tw9kxO4TfQ7bWh0xD9zJRZOpgUJe1D4j9zIxFSa9mHovxIAmZuVAdRfgHicFGiVwi4iU OUnL90cliCXC+I9LtanC8Q1JIFuXx5BdlxLeEX9DablDUFMfIS8auz1nJS4qx5bj6BA8 d3lA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:date:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=B82P8bR5ozDn3yo+U/Bu+4ns+QtyTtYccr3OgXM2Xto=; b=eapQsAuH6+dGuA+kdRuzsVMBRANsolo7xfGLR7zLZFxsdPwjh1D7nBreRhvZhsGNr7 ZmLsKyupkThDPnhVKJATVh7sBWlSEWu1uP4efYEA1pbhQtpKNT3OvcUGHelob2xm4/Iv aa99WlXuOuXRUg08vHOT7ywxVDL/78/p7uDP6JOkZpOBon/b8MfzenO9oMX5s+j9JRUZ KSY8lI+BIc5FywnNCEbLyQ9UdLKKhzordjfV82No0mb5b1q5wGJchm0aWoICMlcpn1BU 6um/CIIHmY2ItJpM/DWediNW3Q9LaWhoOatvZL/kMljF5HAaSFmLI+qEc7z65Ms+QldT 8pcg== X-Gm-Message-State: APjAAAU0boWp08Mxhb3Jj8pIT5bKyPLK4fNMDhQpMiItkr9XtgHOLHgi ilaHdRu5sUlEVZOAk2ikPXw= X-Google-Smtp-Source: APXvYqzcAeFu0IQPSK1BaoWoskfgcIaIoF3n5FvQ9/vQqw2qowCXX07aaHHNTwtuTQh9RE43OOmpHQ== X-Received: by 2002:aed:234a:: with SMTP id i10mr10644028qtc.155.1581352591251; Mon, 10 Feb 2020 08:36:31 -0800 (PST) Received: from rani.riverdale.lan ([2001:470:1f07:5f3::b55f]) by smtp.gmail.com with ESMTPSA id 24sm395392qka.32.2020.02.10.08.36.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 10 Feb 2020 08:36:30 -0800 (PST) From: Arvind Sankar X-Google-Original-From: Arvind Sankar Date: Mon, 10 Feb 2020 11:36:29 -0500 To: Arjan van de Ven Cc: Peter Zijlstra , Kees Cook , Andy Lutomirski , Kristen Carlson Accardi , tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, rick.p.edgecombe@intel.com, x86@kernel.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com Subject: Re: [RFC PATCH 06/11] x86: make sure _etext includes function sections Message-ID: <20200210163627.GA1829035@rani.riverdale.lan> References: <75f0bd0365857ba4442ee69016b63764a8d2ad68.camel@linux.intel.com> <20200207092423.GC14914@hirez.programming.kicks-ass.net> <202002091742.7B1E6BF19@keescook> <20200210105117.GE14879@hirez.programming.kicks-ass.net> <43b7ba31-6dca-488b-8a0e-72d9fdfd1a6b@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <43b7ba31-6dca-488b-8a0e-72d9fdfd1a6b@linux.intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 10, 2020 at 07:54:58AM -0800, Arjan van de Ven wrote: > > > > I'll leave it to others to figure out the exact details. But afaict it > > should be possible to have fine-grained-randomization and preserve the > > workaround in the end. > > > > the most obvious "solution" is to compile with an alignment of 4 bytes (so tight packing) > and then in the randomizer preserve the offset within 32 bytes, no matter what it is > > that would get you an average padding of 16 bytes which is a bit more than now but not too insane > (queue Kees' argument that tiny bits of padding are actually good) > With the patchset for adding the mbranches-within-32B-boundaries option, the section alignment gets forced to 32. With function-sections that means function alignment has to be 32 too.