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=-5.6 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,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 50888C433E0 for ; Tue, 4 Aug 2020 00:48:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5BACD2086A for ; Tue, 4 Aug 2020 00:48:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="TcvSJ7XZ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728012AbgHDAsd (ORCPT ); Mon, 3 Aug 2020 20:48:33 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:23289 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726398AbgHDAsc (ORCPT ); Mon, 3 Aug 2020 20:48:32 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1596502111; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=pni1o6aoiUKtw/3OfYS97iO3vEt5WV4q/1D+eS1+IJs=; b=TcvSJ7XZ/BwwDWzS4tntOJEvnfaZtkSCUPTPJkAmfHFT++9BPmycVGyN3nmIFe3SLct4M8 3uwmlQA2QBrcGl0d8SPUTsohfqnx1Diq7euCgY1GJO2k4n2kjKFM4MoktnObUHN2ujm3AP Hf9Jr0wZOcz6FTNntPbCqwTAttUfXvg= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-228-Q5lytYKUP--GAurLnuzXlQ-1; Mon, 03 Aug 2020 20:48:27 -0400 X-MC-Unique: Q5lytYKUP--GAurLnuzXlQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C60F5100AA23; Tue, 4 Aug 2020 00:48:24 +0000 (UTC) Received: from redhat.com (ovpn-112-64.phx2.redhat.com [10.3.112.64]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 32DEF5D9F7; Tue, 4 Aug 2020 00:48:21 +0000 (UTC) Received: from fche by redhat.com with local (Exim 4.94) (envelope-from ) id 1k2l7p-0008W3-HU; Mon, 03 Aug 2020 20:48:17 -0400 Date: Mon, 3 Aug 2020 20:48:17 -0400 From: "Frank Ch. Eigler" To: Kees Cook 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: <20200804004817.GD30810@redhat.com> References: <20200717170008.5949-1-kristen@linux.intel.com> <202008031043.FE182E9@keescook> <20200803193837.GB30810@redhat.com> <202008031310.4F8DAA20@keescook> <20200803211228.GC30810@redhat.com> <202008031439.F1399A588@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <202008031439.F1399A588@keescook> User-Agent: Mutt/1.12.0 (2019-05-25) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Sender: live-patching-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: live-patching@vger.kernel.org Hi - > > We have relocated based on sections, not some subset of function > > symbols accessible that way, partly because DWARF line- and DIE- based > > probes can map to addresses some way away from function symbols, into > > function interiors, or cloned/moved bits of optimized code. It would > > take some work to prove that function-symbol based heuristic > > arithmetic would have just as much reach. > > Interesting. Do you have an example handy? No, I'm afraid I don't have one that I know cannot possibly be expressed by reference to a function symbol only. I'd look at systemtap (4.3) probe point lists like: % stap -vL 'kernel.statement("*@kernel/*verif*.c:*")' % stap -vL 'module("amdgpu").statement("*@*execution*.c:*")' which give an impression of computed PC addresses. > It seems like something like that would reference the enclosing > section, which means we can't just leave them out of the sysfs > list... (but if such things never happen in the function-sections, > then we *can* remove them...) I'm not sure we can easily prove they can never happen there. - FChE