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=-0.8 required=3.0 tests=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 000EDC3F2CD for ; Mon, 2 Mar 2020 19:20:14 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 5C5A62173E for ; Mon, 2 Mar 2020 19:20:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5C5A62173E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-18042-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 21926 invoked by uid 550); 2 Mar 2020 19:20:08 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Received: (qmail 21906 invoked from network); 2 Mar 2020 19:20:07 -0000 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-IronPort-AV: E=Sophos;i="5.70,508,1574150400"; d="scan'208";a="228570400" Message-ID: <66d6506278121f22c4360110c38ee3653e4fb1c6.camel@linux.intel.com> Subject: Re: [RFC PATCH 09/11] kallsyms: hide layout and expose seed From: Kristen Carlson Accardi To: Kees Cook 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 Date: Mon, 02 Mar 2020 11:19:55 -0800 In-Reply-To: <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> <202003021107.38017F90@keescook> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.30.5 (3.30.5-1.fc29) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit On Mon, 2020-03-02 at 11:08 -0800, Kees Cook wrote: > 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?) > Internally of course we'll always have to have 2 lists. I couldn't find any examples of even root users needing the list to be in order by address. At the same time, it feels like a less risky thing to do to leave root users with the same thing they've always had and only muck with non-root users.