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 DAE5CC3F2D1 for ; Mon, 2 Mar 2020 19:08:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B478A20842 for ; Mon, 2 Mar 2020 19:08:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="jGUWW+rr" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727545AbgCBTIH (ORCPT ); Mon, 2 Mar 2020 14:08:07 -0500 Received: from mail-pj1-f66.google.com ([209.85.216.66]:32893 "EHLO mail-pj1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726451AbgCBTIH (ORCPT ); Mon, 2 Mar 2020 14:08:07 -0500 Received: by mail-pj1-f66.google.com with SMTP id m7so215937pjs.0 for ; Mon, 02 Mar 2020 11:08:04 -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=XbS5Oui71TzDSP82zad1HNkPWeQrHZfwLOAk3ttkqPM=; b=jGUWW+rrTuCc++AiLH0Jj9vkPATEZ//4C63+YRSjlqzn0c9jqq4hDPQi9tXbitIv1u VqLGvPBomCXeewRdCAdzEyMMfvVOASIDci+cn6Mwmiy7QcN2kn9HshsT7n6CqANjidbX SjMtuzQjlBNN7ykH6uerE16g6C1o2QAx56ymw= 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=XbS5Oui71TzDSP82zad1HNkPWeQrHZfwLOAk3ttkqPM=; b=sJt2DcJHMk2WSLpUd0Hfo4Ooi9Cj+WKbqCeLCQ1/ndNMSeh+1RGoJpP7UMHmphizdd 9EFSJ8gRlBpUDAE6eFCveNMd4tbSR/A8U8A8cVEblleIi19GK3/zGQ5WseQBe4PJXlUr muBCj/cVRG1vb6jcAA4vlPKv2vd/uYXy8Ayv6Bar5O7G198dMBt3Ndhp6IWifdq4Mv1B ZEUdFhJsy8a2LkZ1Ge6ozvGQ8vhRKOVtcHa3YCZ/9WPp9JYuZ8kNJ+NqLl1lAjUwdfNz O9inm+iFWV7s31bU9kYVhhIIOrTcy7Iko+qVK9rI0YoXMKU9U2GBokT7yDVOCzKaePIu T0hQ== X-Gm-Message-State: ANhLgQ3jZQAVPF0+oxV+GVp1ELxkYtT+/YY++OG49ta4ZYyrHTVcwa9k js/nnhRDgeEKl1fEzZI0db5HrQ== X-Google-Smtp-Source: ADFU+vs45YCE/A4RV+RfdPn7aH+3QF9x3z2I7E6FgPpDlVlxqDee5DDZoCBVOcK9O/y13IEDwk7Adg== X-Received: by 2002:a17:902:b7c2:: with SMTP id v2mr572385plz.54.1583176084467; Mon, 02 Mar 2020 11:08:04 -0800 (PST) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id r3sm14623739pfq.126.2020.03.02.11.08.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 02 Mar 2020 11:08:03 -0800 (PST) Date: Mon, 2 Mar 2020 11:08:02 -0800 From: Kees Cook To: Kristen Carlson Accardi Cc: Jann Horn , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H . Peter Anvin" , Arjan van de Ven , Rick Edgecombe , the arch/x86 maintainers , kernel list , Kernel Hardening Subject: Re: [RFC PATCH 09/11] kallsyms: hide layout and expose seed Message-ID: <202003021107.38017F90@keescook> References: <20200205223950.1212394-1-kristen@linux.intel.com> <20200205223950.1212394-10-kristen@linux.intel.com> <202002060428.08B14F1@keescook> <41d7049cb704007b3cd30a3f48198eebb8a31783.camel@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <41d7049cb704007b3cd30a3f48198eebb8a31783.camel@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 02, 2020 at 11:01:56AM -0800, Kristen Carlson Accardi wrote: > On Thu, 2020-02-06 at 20:27 +0100, Jann Horn wrote: > > https://codesearch.debian.net/search?q=%2Fproc%2Fkallsyms&literal=1 > > I looked through some of these packages as Jann suggested, and it seems > like there are several that are using /proc/kallsyms to look for > specific symbol names to determine whether some feature has been > compiled into the kernel. This practice seems dubious to me, knowing > that many kernel symbol names can be changed at any time, but > regardless seems to be fairly common. Cool, so a sorted censored list is fine for non-root. Would root users break on a symbol-name-sorted view? (i.e. are two lists needed or can we stick to one?) -- Kees Cook