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=-3.8 required=3.0 tests=BAYES_00, 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 EBC62C433DB for ; Wed, 10 Feb 2021 20:18:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BD82964EDC for ; Wed, 10 Feb 2021 20:18:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233087AbhBJUSL (ORCPT ); Wed, 10 Feb 2021 15:18:11 -0500 Received: from smtp-bc0a.mail.infomaniak.ch ([45.157.188.10]:47009 "EHLO smtp-bc0a.mail.infomaniak.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233035AbhBJURq (ORCPT ); Wed, 10 Feb 2021 15:17:46 -0500 Received: from smtp-2-0000.mail.infomaniak.ch (unknown [10.5.36.107]) by smtp-3-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4DbWJ96DZ5zMq18p; Wed, 10 Feb 2021 21:16:57 +0100 (CET) Received: from ns3096276.ip-94-23-54.eu (unknown [23.97.221.149]) by smtp-2-0000.mail.infomaniak.ch (Postfix) with ESMTPA id 4DbWJ66tgwzlppyf; Wed, 10 Feb 2021 21:16:54 +0100 (CET) Subject: Re: [PATCH v28 07/12] landlock: Support filesystem access-control To: "Serge E. Hallyn" Cc: James Morris , Jann Horn , Al Viro , Andrew Morton , Andy Lutomirski , Anton Ivanov , Arnd Bergmann , Casey Schaufler , Jeff Dike , Jonathan Corbet , Kees Cook , Michael Kerrisk , Richard Weinberger , Shuah Khan , Vincent Dagonneau , kernel-hardening@lists.openwall.com, linux-api@vger.kernel.org, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-security-module@vger.kernel.org, x86@kernel.org, =?UTF-8?Q?Micka=c3=abl_Sala=c3=bcn?= References: <20210202162710.657398-1-mic@digikod.net> <20210202162710.657398-8-mic@digikod.net> <20210210193624.GA29893@mail.hallyn.com> From: =?UTF-8?Q?Micka=c3=abl_Sala=c3=bcn?= Message-ID: Date: Wed, 10 Feb 2021 21:17:25 +0100 User-Agent: MIME-Version: 1.0 In-Reply-To: <20210210193624.GA29893@mail.hallyn.com> Content-Type: text/plain; charset=iso-8859-15 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/02/2021 20:36, Serge E. Hallyn wrote: > On Tue, Feb 02, 2021 at 05:27:05PM +0100, Mickaël Salaün wrote: >> From: Mickaël Salaün >> >> Thanks to the Landlock objects and ruleset, it is possible to identify >> inodes according to a process's domain. To enable an unprivileged > > This throws me off a bit. "identify inodes according to a process's domain". > What exactly does it mean? "identify" how ? A domain is a set of rules (i.e. layers of rulesets) enforced on a set of threads. Inodes are tagged per domain (i.e. not system-wide) and actions are restricted thanks to these tags, which form rules. It means that the created access-controls are scoped to a set of threads. > >> process to express a file hierarchy, it first needs to open a directory >> (or a file) and pass this file descriptor to the kernel through >> landlock_add_rule(2). When checking if a file access request is >> allowed, we walk from the requested dentry to the real root, following >> the different mount layers. The access to each "tagged" inodes are >> collected according to their rule layer level, and ANDed to create >> access to the requested file hierarchy. This makes possible to identify >> a lot of files without tagging every inodes nor modifying the >> filesystem, while still following the view and understanding the user >> has from the filesystem. >> >> Add a new ARCH_EPHEMERAL_INODES for UML because it currently does not >> keep the same struct inodes for the same inodes whereas these inodes are >> in use. > > -serge >