From patchwork Thu Jul 16 12:17:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dominick Grift X-Patchwork-Id: 11667261 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B245413A4 for ; Thu, 16 Jul 2020 12:18:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9859120739 for ; Thu, 16 Jul 2020 12:18:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=defensec.nl header.i=@defensec.nl header.b="TarANw6V" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728094AbgGPMSN (ORCPT ); Thu, 16 Jul 2020 08:18:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55510 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726515AbgGPMSM (ORCPT ); Thu, 16 Jul 2020 08:18:12 -0400 Received: from agnus.defensec.nl (agnus.defensec.nl [IPv6:2001:985:d55d::711]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id B36E8C061755 for ; Thu, 16 Jul 2020 05:18:12 -0700 (PDT) Received: from localhost.localdomain (brutus.lan [IPv6:2001:985:d55d::438]) by agnus.defensec.nl (Postfix) with ESMTPSA id 4D8462A100B; Thu, 16 Jul 2020 14:18:10 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 agnus.defensec.nl 4D8462A100B DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=defensec.nl; s=default; t=1594901891; bh=7YZH4EwTKYzgIcEvsMgthJ+TwYuoKPRvble78+l/K98=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TarANw6VwdUBuO1B9XquFVQpbSE3QbKLR+sjBhSRi7BA2IpqaVjvkhLqrhy2uWY/6 u8kUujiazFazwapbyKCC+hAvecz2f+7Um+BrqwA5GWsYDIzGwS+a2Bdz6J0x2Q+C3u 3P9p9OrVoaeALHsgIYYiOjAaci9NRazJwclQ2yfk= From: Dominick Grift To: selinux@vger.kernel.org Cc: Dominick Grift Subject: [SELinux-notebook PATCH v4] objects.md: some clarifications Date: Thu, 16 Jul 2020 14:17:29 +0200 Message-Id: <20200716121729.962241-1-dominick.grift@defensec.nl> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200716111825.953813-1-dominick.grift@defensec.nl> References: <20200716111825.953813-1-dominick.grift@defensec.nl> MIME-Version: 1.0 Sender: selinux-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org Elaborate on labeling. Touch on the significance of the default statement, on various av permissions related to labeling using the libselinux API, and on how the kernel and unlabeled initial security identifiers are used to address labeling challenges in special cases such as initialization and failover respectively. Signed-off-by: Dominick Grift --- v2: fixes patch description v3: adding patch description, s/policies/policy's/, split unlabeled and kernel descriptions for clarity v4: fixes another typo in description and emphasize system initialization a bit src/objects.md | 29 ++++++++++++++++++++++++++--- 1 file changed, 26 insertions(+), 3 deletions(-) diff --git a/src/objects.md b/src/objects.md index 58664ef..c67787d 100644 --- a/src/objects.md +++ b/src/objects.md @@ -110,14 +110,20 @@ objects is managed by the system and generally unseen by the users (until labeling goes wrong !!). As processes and objects are created and destroyed, they either: -1. Inherit their labels from the parent process or object. +1. Inherit their labels from the parent process or object. The policy + default type, role and range statements can be used to change the + behavior as discussed in the [**Default Rules**](default_rules.md#default-object-rules) + section. 2. The policy type, role and range transition statements allow a different label to be assigned as discussed in the [**Domain and Object Transitions**](domain_object_transitions.md#domain-and-object-transitions) section. 3. SELinux-aware applications can enforce a new label (with the - policies approval of course) using the **libselinux** API - functions. + policy's approval of course) using the **libselinux** API + functions. The `process setfscreate` access vector can be used to + allow subjects to create files with a new label programmatically + using the ***setfscreatecon**(3)* function, overriding default + rules and transition statements. 4. An object manager (OM) can enforce a default label that can either be built into the OM or obtained via a configuration file (such as those used by @@ -269,6 +275,23 @@ and manage their transition: `type_transition`, `role_transition` and `range_transition` +SELinux-aware applications can enforce a new label (with the policy's +approval of course) using the **libselinux** API functions. The +`process setexec`, `process setkeycreate` and `process setsockcreate` +access vectors can be used to allow subjects to label processes, +kernel keyrings, and sockets programmatically using the +***setexec**(3)*, ***setkeycreatecon**(3)* and +***setsockcreatecon**(3)* functions respectively, overriding +transition statements. + +The `kernel` **initial security identifier** is used to associate +specified labels with subjects that were left unlabeled due to +system initialization. + +The `unlabeled` **initial security identifier** is used +to associate specified labels with subjects that had their label +invalidated due to policy changes at runtime. + ### Object Reuse As GNU / Linux runs it creates instances of objects and manages the