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 roberto.sassu@huawei.com --- .../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 + <SHA256 digest1><SHA256 digest2><SHA256 digest3> + version: 1, type: 3, modifiers: 1 algo: 6, count: 2, datalen: 128 + <SHA512 digest1><SHA512 digest2> + +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 a3e8a6f2e34d..b02a8616362b 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -5508,8 +5508,10 @@ 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 linux@roeck-us.net diff --git a/include/uapi/linux/diglim.h b/include/uapi/linux/diglim.h new file mode 100644 index 000000000000..423ad43b0880 --- /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 roberto.sassu@huawei.com + * + * DIGLIM definitions exported to user space, useful for generating digest + * lists. + */ + +#ifndef _UAPI__LINUX_DIGLIM_H +#define _UAPI__LINUX_DIGLIM_H + +#include <linux/types.h> +#include <linux/hash_info.h> + +enum compact_types { 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 set to zero and reserved for future use + * @type: type of digest list among enum compact_types + * @modifiers: bitmask of attributes with pos defined in enum compact_modifiers + * @algo: digest algo among enum hash_algo in include/uapi/linux/hash_info.h + * @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*/