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 6964DC433DF for ; Mon, 3 Aug 2020 21:12:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7A2B022BF3 for ; Mon, 3 Aug 2020 21:12:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="itBpUuOU" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728570AbgHCVMn (ORCPT ); Mon, 3 Aug 2020 17:12:43 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:50940 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729119AbgHCVMn (ORCPT ); Mon, 3 Aug 2020 17:12:43 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1596489162; 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=oDk7BkLvturoY2j4bZcgcnngVm0+SqYFOos8ttHdu5Y=; b=itBpUuOU55gK2BPG0RagsSlnnm9PIyZJeMxtFoFwR3ftTG7tZ4gww6rZ9UmB2WMccXP8lr WrU1HL1kRGxkEYxn0QViv9GH21Cr9coAojBeGQB+aubtVB2KGQNl6Z50+8TOfX54TLCmLu 8Vvq9Sj2tHBEQiOMeac4mymsBpduxIo= 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-41-GjiaqvMBOICm3jt1_nLYPw-1; Mon, 03 Aug 2020 17:12:38 -0400 X-MC-Unique: GjiaqvMBOICm3jt1_nLYPw-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 580D8102C7ED; Mon, 3 Aug 2020 21:12:36 +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 9FFE15D9F7; Mon, 3 Aug 2020 21:12:32 +0000 (UTC) Received: from fche by redhat.com with local (Exim 4.94) (envelope-from ) id 1k2hky-0008Hd-VD; Mon, 03 Aug 2020 17:12:29 -0400 Date: Mon, 3 Aug 2020 17:12:28 -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: <20200803211228.GC30810@redhat.com> References: <20200717170008.5949-1-kristen@linux.intel.com> <202008031043.FE182E9@keescook> <20200803193837.GB30810@redhat.com> <202008031310.4F8DAA20@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <202008031310.4F8DAA20@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 - On Mon, Aug 03, 2020 at 01:11:27PM -0700, Kees Cook wrote: > [...] > > 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... 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. - FChE