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=-4.1 required=3.0 tests=BAYES_00,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 2079BC433DF for ; Mon, 3 Aug 2020 20:11:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C609E2075A for ; Mon, 3 Aug 2020 20:11:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="HeAvcOEz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727091AbgHCULa (ORCPT ); Mon, 3 Aug 2020 16:11:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57696 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727070AbgHCUL3 (ORCPT ); Mon, 3 Aug 2020 16:11:29 -0400 Received: from mail-pl1-x644.google.com (mail-pl1-x644.google.com [IPv6:2607:f8b0:4864:20::644]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EA4F0C06174A for ; Mon, 3 Aug 2020 13:11:29 -0700 (PDT) Received: by mail-pl1-x644.google.com with SMTP id k13so13675381plk.13 for ; Mon, 03 Aug 2020 13:11:29 -0700 (PDT) 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=TfiyLaiiytHrMlT6oh4IsfhQ9YFyy5wx3zu6IU7BZNY=; b=HeAvcOEzYgF+GPngOCTfUbepzuEHkx+8qRmbejrCRY0MMmgn7UeyBWYdJzytoGD/Ta qJv07CPlJcF29ETgPuWONUktPZBp3nwXCAW6eRZRISbnRUQRb/KL+l6+49U1G00uxaJ2 G8Xq9iIuiiHpWvLKYqRaN87kEr5QcIdg7wdbc= 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=TfiyLaiiytHrMlT6oh4IsfhQ9YFyy5wx3zu6IU7BZNY=; b=RvZbbRE1PD54ZcosSZDoJzIJ5g2RnACoZaWO4MLKzjMBaZnFOQh+tw2ntxgHYlTaLH JzmR25djVIDf6bmuoorAnEpHaq+hq/X66NBqcUfAFqaxcgJCEwIlKUh7NVeP4r4SJzEg nZmLDyvca5jwHtizTJ4EB6di/8wHygoTiT7dc7Zdvz35tncRYykyduh3jDhy1fp7sxzz 7DFqrV0iwYwDrZo/bfFf3K/YLniK+BulW7vmh52HQ3zf0xhKV/9Ib9D1GXIYdYiF3Owb QwesQo6+4GAysfril5yVTPsDJSXcr0vLFjaQfLaKF4BHEszaeeRX5Ypq4LPETijvLhXX JCng== X-Gm-Message-State: AOAM533PbGwuOHinNcxNArJq0raeDvR1BREfr+H9iG3B949se4uGtDuk EMn/wB2YODAkNjcH84OdhukTew== X-Google-Smtp-Source: ABdhPJx5soepBCB5jCgc7HTF/4STC+NuKiuSvs2LauZE/NK7WGz7+MhS+gn47Q/oX5PA+CVBiIyxZw== X-Received: by 2002:a17:90a:7f02:: with SMTP id k2mr942128pjl.196.1596485489540; Mon, 03 Aug 2020 13:11:29 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id d2sm18527244pgp.17.2020.08.03.13.11.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 03 Aug 2020 13:11:28 -0700 (PDT) Date: Mon, 3 Aug 2020 13:11:27 -0700 From: Kees Cook To: "Frank Ch. Eigler" Cc: Joe Lawrence , Evgenii Shatokhin , Kristen Carlson Accardi , Miroslav Benes , tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, arjan@linux.intel.com, x86@kernel.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, rick.p.edgecombe@intel.com, live-patching@vger.kernel.org, Josh Poimboeuf , Jessica Yu Subject: Re: [PATCH v4 00/10] Function Granular KASLR Message-ID: <202008031310.4F8DAA20@keescook> References: <20200717170008.5949-1-kristen@linux.intel.com> <202008031043.FE182E9@keescook> <20200803193837.GB30810@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200803193837.GB30810@redhat.com> Sender: live-patching-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: live-patching@vger.kernel.org On Mon, Aug 03, 2020 at 03:38:37PM -0400, Frank Ch. Eigler wrote: > Hi - > > > > While this does seem to be the right solution for the extant problem, I > > > do want to take a moment and ask if the function sections need to be > > > exposed at all? What tools use this information, and do they just want > > > to see the bounds of the code region? (i.e. the start/end of all the > > > .text* sections) Perhaps .text.* could be excluded from the sysfs > > > section list? > > > [[cc += FChE, see [0] for Evgenii's full mail ]] > > Thanks! > > > It looks like debugging tools like systemtap [1], gdb [2] and its > > add-symbol-file cmd, etc. peek at the /sys/module//section/ info. > > But yeah, it would be preferable if we didn't export a long sysfs > > representation if nobody actually needs it. > > Systemtap needs to know base addresses of loaded text & data sections, > in order to perform relocation of probe point PCs and context data > addresses. It uses /sys/module/...., kind of under protest, because > there seems to exist no MODULE_EXPORT'd API to get at that information > some other way. Wouldn't /proc/kallsysms entries cover this? I must be missing something... -- Kees Cook