From patchwork Mon Jul 26 16:36:50 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 12400157 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=-21.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 73302C00143 for ; Mon, 26 Jul 2021 16:40:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6371060FBF for ; Mon, 26 Jul 2021 16:40:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239111AbhGZP7u (ORCPT ); Mon, 26 Jul 2021 11:59:50 -0400 Received: from frasgout.his.huawei.com ([185.176.79.56]:3486 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239750AbhGZP5z (ORCPT ); Mon, 26 Jul 2021 11:57:55 -0400 Received: from fraeml714-chm.china.huawei.com (unknown [172.18.147.206]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4GYQFv5XXVz6GCrW; Tue, 27 Jul 2021 00:23:15 +0800 (CST) Received: from roberto-ThinkStation-P620.huawei.com (10.204.63.22) by fraeml714-chm.china.huawei.com (10.206.15.33) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Mon, 26 Jul 2021 18:38:15 +0200 From: Roberto Sassu To: , , CC: , , , , , Roberto Sassu Subject: [RFC][PATCH v2 02/12] diglim: Basic definitions Date: Mon, 26 Jul 2021 18:36:50 +0200 Message-ID: <20210726163700.2092768-3-roberto.sassu@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210726163700.2092768-1-roberto.sassu@huawei.com> References: <20210726163700.2092768-1-roberto.sassu@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.204.63.22] X-ClientProxiedBy: lhreml754-chm.china.huawei.com (10.201.108.204) To fraeml714-chm.china.huawei.com (10.206.15.33) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org Introduce the basic definitions, exported to user space, to use digest lists. The definitions, added to include/uapi/linux/diglim.h, are documented in Documentation/security/diglim/implementation.rst. Signed-off-by: Roberto Sassu --- .../security/diglim/implementation.rst | 97 +++++++++++++++++++ Documentation/security/diglim/index.rst | 1 + MAINTAINERS | 2 + include/uapi/linux/diglim.h | 51 ++++++++++ 4 files changed, 151 insertions(+) create mode 100644 Documentation/security/diglim/implementation.rst create mode 100644 include/uapi/linux/diglim.h diff --git a/Documentation/security/diglim/implementation.rst b/Documentation/security/diglim/implementation.rst new file mode 100644 index 000000000000..59a180b3bb3f --- /dev/null +++ b/Documentation/security/diglim/implementation.rst @@ -0,0 +1,97 @@ +.. SPDX-License-Identifier: GPL-2.0 + +Implementation +============== + +This section describes the implementation of DIGLIM. + + +Basic Definitions +----------------- + +This section introduces the basic definitions required to use DIGLIM. + + +Compact Digest List Format +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +.. kernel-doc:: include/uapi/linux/diglim.h + :identifiers: compact_list_hdr + +Compact Types +............. + +Digests can be of different types: + +- ``COMPACT_PARSER``: digests of executables which are given the ability to + parse digest lists not in the compact format and to upload to the kernel + the digest list converted to the compact format; +- ``COMPACT_FILE``: digests of regular files; +- ``COMPACT_METADATA``: digests of file metadata (e.g. the digest + calculated by EVM to verify a portable signature); +- ``COMPACT_DIGEST_LIST``: digests of digest lists (only used internally by + the kernel). + +Different users of DIGLIM might query digests with different compact types. +For example, IMA would be interested in COMPACT_FILE, as it deals with +regular files, while EVM would be interested in COMPACT_METADATA, as it +verifies file metadata. + + +Compact Modifiers +................. + +Digests can also have specific attributes called modifiers (bit position): + +- ``COMPACT_MOD_IMMUTABLE``: file content or metadata should not be + modifiable. + +IMA might use this information to deny open for writing, or EVM to deny +setxattr operations. + + +Actions +....... + +This section defines a set of possible actions that have been executed on +the digest lists (bit position): + +- ``COMPACT_ACTION_IMA_MEASURED``: the digest list has been measured by + IMA; +- ``COMPACT_ACTION_IMA_APPRAISED``: the digest list has been successfully + appraised by IMA; +- ``COMPACT_ACTION_IMA_APPRAISED_DIGSIG``: the digest list has been + successfully appraised by IMA by verifying a digital signature. + +This information might help users of DIGLIM to decide whether to use the +result of a queried digest. + +For example, if a digest belongs to a digest list that was not measured +before, IMA should ignore the result of the query, as the measurement list +sent to remote verifiers would lack which digests have been uploaded to the +kernel. + + +Compact Digest List Example +........................... + +:: + + version: 1, type: 2, modifiers: 0 algo: 4, count: 3, datalen: 96 + + version: 1, type: 3, modifiers: 1 algo: 6, count: 2, datalen: 128 + + +This digest list consists of two blocks. The first block contains three +SHA256 digests of regular files. The second block contains two SHA512 +digests of immutable metadata. + + +Compact Digest List Operations +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Finally, this section defines the possible operations that can be performed +with digest lists: + +- ``DIGEST_LIST_ADD``: the digest list is being added; +- ``DIGEST_LIST_DEL``: the digest list is being deleted. diff --git a/Documentation/security/diglim/index.rst b/Documentation/security/diglim/index.rst index 0fc5ab019bc0..4771134c2f0d 100644 --- a/Documentation/security/diglim/index.rst +++ b/Documentation/security/diglim/index.rst @@ -9,3 +9,4 @@ Digest Lists Integrity Module (DIGLIM) introduction architecture + implementation diff --git a/MAINTAINERS b/MAINTAINERS index c914dadd7e65..f61f5239468a 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -5458,8 +5458,10 @@ L: linux-integrity@vger.kernel.org S: Supported T: git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity.git F: Documentation/security/diglim/architecture.rst +F: Documentation/security/diglim/implementation.rst F: Documentation/security/diglim/index.rst F: Documentation/security/diglim/introduction.rst +F: include/uapi/linux/diglim.h DIOLAN U2C-12 I2C DRIVER M: Guenter Roeck diff --git a/include/uapi/linux/diglim.h b/include/uapi/linux/diglim.h new file mode 100644 index 000000000000..8a33d1f0fefb --- /dev/null +++ b/include/uapi/linux/diglim.h @@ -0,0 +1,51 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +/* + * Copyright (C) 2017-2021 Huawei Technologies Duesseldorf GmbH + * + * Author: Roberto Sassu + * + * DIGLIM definitions exported to user space, useful for generating digest + * lists. + */ + +#ifndef _UAPI__LINUX_DIGLIM_H +#define _UAPI__LINUX_DIGLIM_H + +#include +#include + +enum compact_types { COMPACT_KEY, COMPACT_PARSER, COMPACT_FILE, + COMPACT_METADATA, COMPACT_DIGEST_LIST, COMPACT__LAST }; + +enum compact_modifiers { COMPACT_MOD_IMMUTABLE, COMPACT_MOD__LAST }; + +enum compact_actions { COMPACT_ACTION_IMA_MEASURED, + COMPACT_ACTION_IMA_APPRAISED, + COMPACT_ACTION_IMA_APPRAISED_DIGSIG, + COMPACT_ACTION__LAST }; + +enum ops { DIGEST_LIST_ADD, DIGEST_LIST_DEL, DIGEST_LIST_OP__LAST }; + +/** + * struct compact_list_hdr - header of the following concatenated digests + * @version: version of the digest list + * @_reserved: field reserved for future use + * @type: type of digest list among enum compact_types + * @modifiers: additional attributes among (1 << enum compact_modifiers) + * @algo: digest algorithm + * @count: number of digests + * @datalen: length of concatenated digests + * + * A digest list is a set of blocks composed by struct compact_list_hdr and + * the following concatenated digests. + */ +struct compact_list_hdr { + __u8 version; + __u8 _reserved; + __le16 type; + __le16 modifiers; + __le16 algo; + __le32 count; + __le32 datalen; +} __packed; +#endif /*_UAPI__LINUX_DIGLIM_H*/