From patchwork Sat Jul 18 06:40:22 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dominick Grift X-Patchwork-Id: 11671707 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 2F4B813B4 for ; Sat, 18 Jul 2020 06:40:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D945B2074B for ; Sat, 18 Jul 2020 06:40:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=defensec.nl header.i=@defensec.nl header.b="TCT9xeBe" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726672AbgGRGkg (ORCPT ); Sat, 18 Jul 2020 02:40:36 -0400 Received: from agnus.defensec.nl ([80.100.19.56]:54812 "EHLO agnus.defensec.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726551AbgGRGkg (ORCPT ); Sat, 18 Jul 2020 02:40:36 -0400 Received: from localhost.localdomain (brutus [IPv6:2001:985:d55d::438]) by agnus.defensec.nl (Postfix) with ESMTPSA id 2129B2A1007; Sat, 18 Jul 2020 08:40:32 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 agnus.defensec.nl 2129B2A1007 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=defensec.nl; s=default; t=1595054433; bh=rHxkvrjUHvOta1mVOQPA5Y5E591psr1Vti2AhixLyhU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TCT9xeBe6NvvmckI96wy6Ai2bvgGcZ+icwxUreBCmEhjG/wbOQ6ZkJ7ikqoUMMfRb HU4uKjMBhC372rl3/HmVRL4YT80gcjFDK8KcW0/sQwETQaurbq9V2PIM/CcdIyPwQo rt7I2UKIo9sMonHBNcZ9EbV6ePeSWWPjjFU973I4= From: Dominick Grift To: selinux@vger.kernel.org Cc: Dominick Grift Subject: [SELinux-notebook PATCH v5] objects.md: some clarifications Date: Sat, 18 Jul 2020 08:40:22 +0200 Message-Id: <20200718064022.1300044-1-dominick.grift@defensec.nl> X-Mailer: git-send-email 2.27.0 In-Reply-To: References: 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 v5: emphasize kernel threads with kernel isid description src/objects.md | 29 ++++++++++++++++++++++++++--- 1 file changed, 26 insertions(+), 3 deletions(-) diff --git a/src/objects.md b/src/objects.md index 58664ef..70877b0 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, for example kernel threads. + +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