From patchwork Fri Jul 17 22:28:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lakshmi Ramasubramanian X-Patchwork-Id: 11671285 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 E432D1751 for ; Fri, 17 Jul 2020 22:28:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CDB762074B for ; Fri, 17 Jul 2020 22:28:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="G3DCLDQD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726691AbgGQW2Z (ORCPT ); Fri, 17 Jul 2020 18:28:25 -0400 Received: from linux.microsoft.com ([13.77.154.182]:46022 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726205AbgGQW2Z (ORCPT ); Fri, 17 Jul 2020 18:28:25 -0400 Received: from localhost.localdomain (c-73-42-176-67.hsd1.wa.comcast.net [73.42.176.67]) by linux.microsoft.com (Postfix) with ESMTPSA id 3956D20B4909; Fri, 17 Jul 2020 15:28:24 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 3956D20B4909 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1595024904; bh=KpquaLMTCsotXw43iiktbn5HJNp8nj0fPskNFWyGEoc=; h=From:To:Cc:Subject:Date:From; b=G3DCLDQDOICLFIcReFxebPr3PaGzUWTfWEayKb/aHcPo247UaZ7FwRpAHWu2Knh0e HKHuULyTvzjNtNmdiExSggRqRqYPCGnjIymtRxWqZGXj7yAbxCPz5Nq9xdxDcr6oZb q8JBwPPAZiQ7a0vDPqruFHk59/mHbcsRmq9zE/Lg= From: Lakshmi Ramasubramanian To: zohar@linux.ibm.com, stephen.smalley.work@gmail.com, casey@schaufler-ca.com Cc: jmorris@namei.org, linux-integrity@vger.kernel.org, selinux@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 0/5] LSM: Measure security module state Date: Fri, 17 Jul 2020 15:28:14 -0700 Message-Id: <20200717222819.26198-1-nramas@linux.microsoft.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Sender: selinux-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org Critical data structures of security modules are currently not measured. Therefore an attestation service, for instance, would not be able to attest whether the security modules are always operating with the policies and configuration that the system administrator had setup. The policies and configuration for the security modules could be tampered with by malware by exploiting Kernel vulnerabilities or modified through some inadvertent actions on the system. Measuring such critical data would enable an attestation service to better assess the state of the system. IMA subsystem measures system files, command line arguments passed to kexec, boot aggregate, keys, etc. It can be used to measure critical data structures of security modules as well. This change aims to address measuring critical data structures of security modules when they are initialized, when they are updated at runtime, and also periodically to detect any tampering. This change set is based off of Linux Kernel version 5.8-rc5. The following patch needs to be applied first before applying the patches in this patch set: https://patchwork.kernel.org/patch/11612989/ Change log: v3: => Loop through policy_capabilities to build the state data to measure instead of hardcoding to current set of policy capabilities. => Added error log messages for failure conditions. v2: => Pass selinux_state struct as parameter to the function that measures SELinux data. => Use strings from selinux_policycap_names array for SELinux state measurement. => Refactored security_read_policy() to alloc kernel or user virtual memory and then read the SELinux policy. v1: => Per Stephen Smalley's suggestion added selinux_state booleans and hash of SELinux policy in the measured data for SELinux. => Call IMA hook from the security module directly instead of redirecting through the LSM. Lakshmi Ramasubramanian (5): IMA: Add LSM_STATE func to measure LSM data IMA: Define an IMA hook to measure LSM data LSM: Add security_measure_data in lsm_info struct LSM: Define SELinux function to measure security state LSM: Define workqueue for measuring security module state Documentation/ABI/testing/ima_policy | 6 +- include/linux/ima.h | 4 + include/linux/lsm_hooks.h | 3 + security/integrity/ima/ima.h | 1 + security/integrity/ima/ima_api.c | 2 +- security/integrity/ima/ima_main.c | 17 +++ security/integrity/ima/ima_policy.c | 29 ++++- security/security.c | 74 ++++++++++++- security/selinux/Makefile | 2 + security/selinux/hooks.c | 4 + security/selinux/include/security.h | 18 ++++ security/selinux/measure.c | 155 +++++++++++++++++++++++++++ security/selinux/selinuxfs.c | 1 + security/selinux/ss/services.c | 66 ++++++++++-- 14 files changed, 365 insertions(+), 17 deletions(-) create mode 100644 security/selinux/measure.c