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 66DF8C3F2D7 for ; Mon, 2 Mar 2020 19:08:23 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id B990920842 for ; Mon, 2 Mar 2020 19:08:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="jGUWW+rr" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B990920842 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-18041-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 15675 invoked by uid 550); 2 Mar 2020 19:08:17 -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 15654 invoked from network); 2 Mar 2020 19:08:16 -0000 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=ohLvlfGWpUeHrbAJQoL6pbrkhsjy4z8BYADKDX+2tbekHRreIY/BHz7CfbhrqUwXfR MYk+TFq/pV1+AnIxKmLw+gYgMGBTy8HUM3mwAE3Bw3fLIYNlSoF/KFwOkRl15R6LlOXp TfekT5HEa0PdlAXX34VIbq2GPsBN0w/dT6wuLnFVLHwS4HnmrPK8e/w6UaIwBQ2NXKkm 048F1GW9/lAeseLN5+Kj5Oqf3SyGeW8WnKYghkmv82cLS1ItHXlUebcmNtVS+jKU+eaa A77vN1WJiBOJYASCaPwrH3dMlopiTBotynUfwylpb7ntQCFIULU31ATi/No8i+XalMBV y2gw== X-Gm-Message-State: ANhLgQ0j7FLQkPP0rUSkiDxHmKrZrE1p4x22ETIRDQ9AjDxo66FriYe0 SnfqbUXZ9klSN1VwqbqBZ1xVjQ== 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) 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> 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