From patchwork Tue Feb 1 20:37:08 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Berger X-Patchwork-Id: 12732280 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 37AD6C4167D for ; Tue, 1 Feb 2022 20:39:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242576AbiBAUi7 (ORCPT ); Tue, 1 Feb 2022 15:38:59 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:65528 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S240496AbiBAUiS (ORCPT ); Tue, 1 Feb 2022 15:38:18 -0500 Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 211JO833019417; Tue, 1 Feb 2022 20:37:54 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : content-transfer-encoding : mime-version; s=pp1; bh=Og3txdzqkfs8InhektoyI7avE3IeDNY1Wrnk4jJ0I/M=; b=STlDSdcLGJyg3jV+j1TOEn/sHruqTHhA/tUIJqLVsBesH78KNAPsIGwkuNbJPGvSM/8l rhUlQ+OK6P1DdJCgvYwSWZ8lZeJ2Su39lcGuQs0qdmvoZw6xlNeqZPHWAXS21UDfhdDS xEwSrCOFxiJmOg2nZQvYfEkbxOJ5wKYdKs0Ct4SQuNM42YaMewXCxk29ak3qPCTr0oMq 4wwMggwJqD5aPWutTZCbkObfhp2+pVYoC4coueIdCwKil0dZichZ6wlbXiVJI7Y2yBf7 erdEr5mqETxCC+mF9tgf1v/ZNEeJXd1kQvDsytBiqQW2Lij82iiYik+jlJD4QPk39g7w eQ== Received: from pps.reinject (localhost [127.0.0.1]) by mx0b-001b2d01.pphosted.com with ESMTP id 3dyb01s76k-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 01 Feb 2022 20:37:53 +0000 Received: from m0098416.ppops.net (m0098416.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.43/8.16.0.43) with SMTP id 211JOmDw020525; Tue, 1 Feb 2022 20:37:53 GMT Received: from ppma02wdc.us.ibm.com (aa.5b.37a9.ip4.static.sl-reverse.com [169.55.91.170]) by mx0b-001b2d01.pphosted.com with ESMTP id 3dyb01s75y-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 01 Feb 2022 20:37:53 +0000 Received: from pps.filterd (ppma02wdc.us.ibm.com [127.0.0.1]) by ppma02wdc.us.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 211KWNbY014800; Tue, 1 Feb 2022 20:37:52 GMT Received: from b01cxnp22033.gho.pok.ibm.com (b01cxnp22033.gho.pok.ibm.com [9.57.198.23]) by ppma02wdc.us.ibm.com with ESMTP id 3dvw7b152d-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 01 Feb 2022 20:37:52 +0000 Received: from b01ledav003.gho.pok.ibm.com (b01ledav003.gho.pok.ibm.com [9.57.199.108]) by b01cxnp22033.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 211KbnFn14746096 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 1 Feb 2022 20:37:49 GMT Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 14E29B2074; Tue, 1 Feb 2022 20:37:49 +0000 (GMT) Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E7E32B206A; Tue, 1 Feb 2022 20:37:48 +0000 (GMT) Received: from sbct-3.pok.ibm.com (unknown [9.47.158.153]) by b01ledav003.gho.pok.ibm.com (Postfix) with ESMTP; Tue, 1 Feb 2022 20:37:48 +0000 (GMT) From: Stefan Berger To: linux-integrity@vger.kernel.org Cc: zohar@linux.ibm.com, serge@hallyn.com, christian.brauner@ubuntu.com, containers@lists.linux.dev, dmitry.kasatkin@gmail.com, ebiederm@xmission.com, krzysztof.struczynski@huawei.com, roberto.sassu@huawei.com, mpeters@redhat.com, lhinds@redhat.com, lsturman@redhat.com, puiterwi@redhat.com, jejb@linux.ibm.com, jamjoom@us.ibm.com, linux-kernel@vger.kernel.org, paul@paul-moore.com, rgb@redhat.com, linux-security-module@vger.kernel.org, jmorris@namei.org, Stefan Berger Subject: [PATCH v10 00/27] ima: Namespace IMA with audit support in IMA-ns Date: Tue, 1 Feb 2022 15:37:08 -0500 Message-Id: <20220201203735.164593-1-stefanb@linux.ibm.com> X-Mailer: git-send-email 2.34.1 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: sKJvVFEA-4F91046--uzQ3gEXZxTyvVe X-Proofpoint-ORIG-GUID: toA1sdCcG2PI42KZf-E9B3p8f8mfiVKf X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.816,Hydra:6.0.425,FMLib:17.11.62.513 definitions=2022-02-01_09,2022-02-01_01,2021-12-02_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 impostorscore=0 clxscore=1015 malwarescore=0 mlxlogscore=999 phishscore=0 priorityscore=1501 spamscore=0 mlxscore=0 adultscore=0 suspectscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2201110000 definitions=main-2202010114 Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org The goal of this series of patches is to start with the namespacing of IMA and support auditing within an IMA namespace (IMA-ns) as the first step. In this series the IMA namespace is piggy backing on the user namespace and therefore an IMA namespace is created when a user namespace is created, although this is done late when SecurityFS is mounted inside a user namespace. The advantage of piggy backing on the user namespace is that the user namespace can provide the keys infrastructure that IMA appraisal support will need later on. We chose the goal of supporting auditing within an IMA namespace since it requires the least changes to IMA. Following this series, auditing within an IMA namespace can be activated by a user running the following lines that rely on a statically linked busybox to be installed on the host for execution within the minimal container environment: mkdir -p rootfs/{bin,mnt,proc} cp /sbin/busybox rootfs/bin cp /sbin/busybox rootfs/bin/busybox2 echo >> rootfs/bin/busybox2 PATH=/bin unshare --user --map-root-user --mount-proc --pid --fork \ --root rootfs busybox sh -c \ "busybox mount -t securityfs /mnt /mnt; \ busybox echo 1 > /mnt/ima/active; \ busybox echo 'audit func=BPRM_CHECK mask=MAY_EXEC' > /mnt/ima/policy; \ busybox2 cat /mnt/ima/policy" [busybox2 is used to demonstrate 2 audit messages; see below] Following the audit log on the host the last line cat'ing the IMA policy inside the namespace would have been audited. Unfortunately the auditing line is not distinguishable from one stemming from actions on the host. The hope here is that Richard Brigg's container id support for auditing would help resolve the problem. In the above the writing of '1' to the 'active' file is used to activate the IMA namespace. Future extensions to IMA namespaces will make use of the configuration stage after the mounting of securityfs and before the activation to for example choose the measurement log template. The following lines added to a suitable IMA policy on the host would cause the execution of the commands inside the container (by uid 1000) to be measured and audited as well on the host, thus leading to two auditing messages for the 'busybox2 cat' above and log entries in IMA's system log. echo -e "measure func=BPRM_CHECK mask=MAY_EXEC uid=1000\n" \ "audit func=BPRM_CHECK mask=MAY_EXEC uid=1000\n" \ > /sys/kernel/security/ima/policy The goal of supporting measurement and auditing by the host, of actions occurring within IMA namespaces, is that users, particularly root, should not be able to evade the host's IMA policy just by spawning new IMA namespaces, running programs there, and discarding the namespaces again. This is achieved through 'hierarchical processing' of file accesses that are evaluated against the policy of the namespace where the action occurred and against all namespaces' and their policies leading back to the root IMA namespace (init_ima_ns). The patch series adds support for a virtualized SecurityFS with a few new API calls that are used by IMA namespacing. Only the data relevant to the IMA namespace are shown. The files and directories of other security subsystems (TPM, evm, Tomoyo, safesetid) are not showing up when secruityfs is mounted inside a user namespace. Much of the code leading up to the virtualization of SecurityFS deals with moving IMA's variables from various files into the IMA namespace structure called 'ima_namespace'. When it comes to determining the current IMA namespace I took the approach to get the current IMA namespace (get_current_ns()) on the top level and pass the pointer all the way down to those functions that now need access to the ima_namespace to get to their variables. This later on comes in handy once hierarchical processing is implemented in this series where we walk the list of namespaces backwards and again need to pass the pointer into functions. This patch also introduces usage of CAP_MAC_ADMIN to allow access to the IMA policy via reduced capabilities. We would again later on use this capability to allow users to set file extended attributes for IMA appraisal support. My tree with these patches is here: git fetch https://github.com/stefanberger/linux-ima-namespaces v5.16+imans.v10.posted Regards, Stefan Links to previous postings: v1: https://lore.kernel.org/linux-integrity/20211130160654.1418231-1-stefanb@linux.ibm.com/T/#t v2: https://lore.kernel.org/linux-integrity/20211203023118.1447229-1-stefanb@linux.ibm.com/T/#t v3: https://lore.kernel.org/linux-integrity/6240b686-89cf-2e31-1c1b-ebdcf1e972c1@linux.ibm.com/T/#t v4: https://lore.kernel.org/linux-integrity/20211207202127.1508689-1-stefanb@linux.ibm.com/T/#t v5: https://lore.kernel.org/linux-integrity/20211208221818.1519628-1-stefanb@linux.ibm.com/T/#t v6: https://lore.kernel.org/linux-integrity/20211210194736.1538863-1-stefanb@linux.ibm.com/T/#t v7: https://lore.kernel.org/linux-integrity/20211217100659.2iah5prshavjk6v6@wittgenstein/T/#t v8: https://lore.kernel.org/all/20220104170416.1923685-1-stefanb@linux.vnet.ibm.com/#r v9: https://lore.kernel.org/linux-integrity/?t=20220131234353 v10: - Added A-b's; addressed issues from v9 - Added 2 patches to support freeing of iint after namespace deletion - Added patch to return error code from securityfs functions - Added patch to limit number of policy rules in IMA-ns to 1024 v9: - Rearranged order of patch that adds IMA-ns pointer to user_ns to be before hierarchical processing patch - Renamed ns_status variables from status to ns_status to avoid clashes - Added bug fixing patches to top - Added patch 'Move arch_policy_entry into ima_namespace' - Added patch 'Move ima_lsm_policy_notifier into ima_namespace' - Addressed comments to v8 - Added change comments to individual patches - Formatted code following checkpatch.pl --strict v8: - Rearranged patches to support lazy creation of IMA namespaces - Fixed issue related to re-auditing of a modified file. This required the introduction of ns_status structure connected to list starting on an iint - Fixed issue related to display of uid and gid in IMA policy to show uid and gid values relative to the user namespace - Handling of error code during hierarchical processing v7: - Dropped 2 patches related to key queues; using &init_ima_ns for all calls from functions related to key queues where calls need ima_namespace - Moved ima_namespace to security/integrity/ima/ima.h - Extended API descriptions with ns parameter where needed - Using init_ima_ns in functions related to appraisal and xattrs - SecurityFS: Using ima_ns_from_file() to get ns pointer - Reformatted to 80 columns per line v6: - Removed kref and pointer to user_ns in ima_namespace (patch 1) - Moved only the policy file dentry into ima_namespace; other dentries are on stack now and can be discarded - Merged James's patch simplifying securityfs_remove and dropping dget() - Added patch with Christian's suggestion to tie opened SecurityFS file to the user/IMA namespace it belongs to - Passing missing ima_namespace parameter in functions in ima_kexec.c (ppc64) - Reverted v5's change to patch 4 related to protection of ima_namespace v5: - Followed Christian's suggestions on patch 1. Also, reverted increased reference counter on init_user_ns since ima_ns doesn't take reference to its user_ns. - No addtional reference is taken on securityfs dentries for user_ns != init_user_ns. Updated documentation and removed cleanup of dentries on superblock kill. (patches 12 & 16) - Moved else branch to earlier patch (patch 11) - Protect ima_namespace by taking reference on user namespace for delayed work queue. (patch 4) v4: - For consistency moved 'ns = get_current_ns()' to top of functions - Merge in James's latest SecurityFS patch v3: - Further modifications to virtualized SecurityFS following James's posted patch - Dropping of early teardown for user_namespaces since not needed anymore v2: - Folllwed Christian's suggestion to virtualize securitytfs; no more securityfs_ns - Followed James's advice for late 'population' of securityfs for IMA namespaces - Squashed 2 patches dealing with capabilities - Added missing 'depends on USER_NS' to Kconfig - Added missing 'static' to several functions Christian Brauner (1): securityfs: rework dentry creation Mehmet Kayaalp (2): integrity/ima: Define ns_status for storing namespaced iint data ima: Namespace audit status flags Stefan Berger (24): ima: Remove ima_policy file before directory ima: Do not print policy rule with inactive LSM labels ima: Return error code obtained from securityfs functions ima: Define ima_namespace struct and start moving variables into it ima: Move arch_policy_entry into ima_namespace ima: Move ima_htable into ima_namespace ima: Move measurement list related variables into ima_namespace ima: Move some IMA policy and filesystem related variables into ima_namespace ima: Move IMA securityfs files into ima_namespace or onto stack ima: Move ima_lsm_policy_notifier into ima_namespace ima: Define mac_admin_ns_capable() as a wrapper for ns_capable() ima: Only accept AUDIT rules for non-init_ima_ns namespaces for now userns: Add pointer to ima_namespace to user_namespace ima: Implement hierarchical processing of file accesses ima: Implement ima_free_policy_rules() for freeing of an ima_namespace ima: Add functions for creating and freeing of an ima_namespace integrity: Add optional callback function to integrity_inode_free() ima: Remove unused iints from the integrity_iint_cache securityfs: Extend securityfs with namespacing support ima: Setup securityfs for IMA namespace ima: Introduce securityfs file to activate an IMA namespace ima: Show owning user namespace's uid and gid when displaying policy ima: Limit number of policy rules in non-init_ima_ns ima: Enable IMA namespaces include/linux/capability.h | 6 + include/linux/ima.h | 36 ++ include/linux/integrity.h | 8 +- include/linux/user_namespace.h | 4 + init/Kconfig | 13 + kernel/user.c | 4 + kernel/user_namespace.c | 2 + security/inode.c | 81 +++- security/integrity/iint.c | 26 +- security/integrity/ima/Makefile | 3 +- security/integrity/ima/ima.h | 241 ++++++++++-- security/integrity/ima/ima_api.c | 34 +- security/integrity/ima/ima_appraise.c | 31 +- security/integrity/ima/ima_asymmetric_keys.c | 8 +- security/integrity/ima/ima_fs.c | 299 +++++++++++--- security/integrity/ima/ima_init.c | 19 +- security/integrity/ima/ima_init_ima_ns.c | 65 ++++ security/integrity/ima/ima_kexec.c | 15 +- security/integrity/ima/ima_main.c | 223 ++++++++--- security/integrity/ima/ima_ns.c | 61 +++ security/integrity/ima/ima_ns_status.c | 385 +++++++++++++++++++ security/integrity/ima/ima_policy.c | 266 ++++++++----- security/integrity/ima/ima_queue.c | 63 ++- security/integrity/ima/ima_queue_keys.c | 11 +- security/integrity/ima/ima_template.c | 5 +- security/integrity/integrity.h | 39 +- security/security.c | 2 +- 27 files changed, 1606 insertions(+), 344 deletions(-) create mode 100644 security/integrity/ima/ima_init_ima_ns.c create mode 100644 security/integrity/ima/ima_ns.c create mode 100644 security/integrity/ima/ima_ns_status.c