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=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1,USER_IN_DEF_DKIM_WL 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 C601DC2BB1D for ; Thu, 9 Apr 2020 16:26:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9CD8620768 for ; Thu, 9 Apr 2020 16:26:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="SVIUfVQP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726817AbgDIQZ7 (ORCPT ); Thu, 9 Apr 2020 12:25:59 -0400 Received: from linux.microsoft.com ([13.77.154.182]:54992 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726621AbgDIQZ6 (ORCPT ); Thu, 9 Apr 2020 12:25:58 -0400 Received: from [10.137.106.115] (unknown [131.107.174.243]) by linux.microsoft.com (Postfix) with ESMTPSA id CC37A2007679; Thu, 9 Apr 2020 09:25:57 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com CC37A2007679 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1586449558; bh=mxgHZSJk9nY2+sfPQybAXK1hYlxOn5wF6OLSUaiTeXQ=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=SVIUfVQPfYXivTtnf81II2+cuX+VuuFT/cdRyrSfPQa/NspfBGhnRo9yWKcDnzRbk LJ3Ki75Ows6uAhw3zh0yXVdiT1bgycAFmEUG1RPPnFEYcitcKAqCmE0Cd8qQo22Fey 1mwwxBUG5vr/LHYHNEZymvqJ6fmpTEryjbQU2kPw= Subject: Re: [RFC PATCH v2 00/12] Integrity Policy Enforcement LSM (IPE) To: Nayna Cc: agk@redhat.com, axboe@kernel.dk, snitzer@redhat.com, jmorris@namei.org, serge@hallyn.com, zohar@linux.ibm.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, dm-devel@redhat.com, linux-block@vger.kernel.org, tyhicks@linux.microsoft.com, pasha.tatashin@soleen.com, sashal@kernel.org, jaskarankhurana@linux.microsoft.com, nramas@linux.microsoft.com, mdsakib@linux.microsoft.com, linux-kernel@vger.kernel.org References: <20200406221439.1469862-1-deven.desai@linux.microsoft.com> From: Deven Bowers Message-ID: <35afdffe-179c-aedd-333a-9dfc20635fc3@linux.microsoft.com> Date: Thu, 9 Apr 2020 09:25:57 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/7/2020 2:31 PM, Nayna wrote: > > On 4/6/20 6:14 PM, deven.desai@linux.microsoft.com wrote: >> From: Deven Bowers >> >> Changelog: >> ------------------------------------ >> >> v1: Introduced >> >> v2: >>    Split the second patch of the previous series into two. >>    Minor corrections in the cover-letter and documentation >>    comments regarding CAP_MAC_ADMIN checks in IPE. >> >> Overview: >> ------------------------------------ >> IPE is a Linux Security Module, which allows for a configurable >> policy to enforce integrity requirements on the whole system. It >> attempts to solve the issue of Code Integrity: that any code being >> executed (or files being read), are identical to the version that >> was built by a trusted source. > > Can you please clarify the "motivation" for this patch set more > clearly? It seems to define a policy layer on top of dm-verity, which > may be compiled into the kernel. In the motivation, can you please > also make it explicit why existing mechanisms cannot be extended to > achieve your purpose? > This LSM was born out of a motivation to provide strong integrity guarantees without a dependency on file-metadata, allow the integrity claims to be configurable on a hot system, and allow for the mechanisms for ensuring integrity to be extendable. This naturally had to be an LSM, as controlling execution at the block or filesystem layer does not make sense. Existing LSM implementations use filesystem metadata, and since one of IPE's goals is to secure file metadata, it is circular to depend on the file metadata itself to make decisions about whether the file has been modified. Additionally, IPE while IPE currently provides dm-verity support and the trust root support, it can be easily extended to other implementations such as fs-verity. At it's core, IPE is attempting to separate mechanism (dm-verity, fs-verity, etc.) from policy (IPE). > Also, AFIK, the changelog should be moved to the end of the patch > description. > Thanks! I'll move the changelog.