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In: AD_Evaluation
SACM Working Group H. Birkholz
Internet-Draft Fraunhofer SIT
Intended status: Standards Track J. Fitzgerald-McKay
Expires: July 8, 2018 Department of Defense
C. Schmidt
The MITRE Corporation
D. Waltermire
NIST
January 04, 2018
Concise Software Identifiers
draft-ietf-sacm-coswid-03
Abstract
This document defines a concise representation of ISO 19770-2:2015
Software Identifiers (SWID tags) that is interoperable with the XML
schema definition of ISO 19770-2:2015 and augmented for application
in Constrained-Node Networks. Next to the inherent capability of
SWID tags to express arbitrary context information, CoSWID support
the definition of additional semantics via well-defined data
definitions incorporated by extension points.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on July 8, 2018.
Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Concise SWID Extensions . . . . . . . . . . . . . . . . . 4
1.2. Requirements Notation . . . . . . . . . . . . . . . . . . 4
2. Concise SWID Data Definition . . . . . . . . . . . . . . . . 4
3. Description of the SWID Attribute Vocabulary Definition . . . 9
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
5. Security Considerations . . . . . . . . . . . . . . . . . . . 9
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11
7. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 11
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 12
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
9.1. Normative References . . . . . . . . . . . . . . . . . . 12
9.2. Informative References . . . . . . . . . . . . . . . . . 13
Appendix A. Explicit file-hash Type Used in Concise SWID Tags
(label 56) . . . . . . . . . . . . . . . . . . . . . 14
Appendix B. CoSWID Attributes for Firmware (label 57) . . . . . 14
Appendix C. Signed Concise SWID Tags using COSE . . . . . . . . 16
Appendix D. CoSWID used as Reference Integrity Measurements
(CoSWID RIM) . . . . . . . . . . . . . . . . . . . . 17
Appendix E. CBOR Web Token for Concise SWID Tags . . . . . . . . 18
Appendix F. Group Definitions . . . . . . . . . . . . . . . . . 18
Appendix G. Item Definitions . . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 26
1. Introduction
SWID tags have several use-applications including but not limited to:
o Software Inventory Management, a part of the Software Asset
Management [SAM] process, which requires an accurate list of
discernible deployed software components.
o Vulnerability Assessment, which requires a semantic link between
standardized vulnerability descriptions and IT-assets [X.1520].
o Remote Attestation, which requires a link between reference
integrity measurements (RIM) and security logs of measured
software components [I-D.birkholz-tuda].
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SWID tags, as defined in ISO-19770-2:2015 [SWID], provide a
standardized format for a record that identifies and describes a
specific release of a software product. Different software products,
and even different releases of a particular software product, each
have a different SWID tag record associated with them. In addition
to defining the format of these records, ISO-19770-2:2015 defines
requirements concerning the SWID tag life-cycle. Specifically, when
a software product is installed on an endpoint, that product's SWID
tag is also installed. Likewise, when the product is uninstalled or
replaced, the SWID tag is deleted or replaced, as appropriate. As a
result, ISO-19770-2:2015 describes a system wherein there is a
correspondence between the set of installed software products on an
endpoint, and the presence on that endpoint of the SWID tags
corresponding to those products.
SWID tags are meant to be flexible and able to express a broad set of
metadata about a software product. Moreover, there are multiple
types of SWID tags, each providing different types of information.
For example, a "corpus tag" is used to describe an application's
installation image on an installation media, while a "patch tag" is
meant to describe a patch that modifies some other application.
While there are very few required fields in SWID tags, there are many
optional fields that support different uses of these different types
of tags. While a SWID tag that consisted only of required fields
could be a few hundred bytes in size, a tag containing many of the
optional fields could be many orders of magnitude larger.
This document defines a more concise representation of SWID tags in
the Concise Binary Object Representation (CBOR) [RFC7049]. This is
described via the Concise Data Definition Language (CDDL)
[I-D.ietf-cbor-cddl]. The resulting Concise SWID data definition is
interoperable with the XML schema definition of ISO-19770-2:2015
[SWID]. The vocabulary, i.e., the CDDL names of the types and
members used in the CoSWID data definition, is mapped to more concise
labels represented as small integers. The names used in the CDDL
data definition and the mapping to the CBOR representation using
integer labels is based on the vocabulary of the XML attribute and
element names defined in ISO-19770-2:2015.
Real-world instances of SWID tags can be fairly large, and the
communication of SWID tags in use-applications such as those
described earlier can cause a large amount of data to be transported.
This can be larger than acceptable for constrained devices and
networks. CoSWID tags significantly reduce the amount of data
transported as compared to a typical SWID tag. This reduction is
enable through the use of CBOR, which maps human-readable labels of
that content to more concise integer labels (indices). This allows
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SWID tags to be part of an enterprise security solution for a wider
range of endpoints and environments.
1.1. Concise SWID Extensions
This document specifies a standard equivalent to the ISO-19770-2:2015
standard. The corresponding CoSWID data definition includes two
kinds of augmentation.
o the explicit definition of types for attributes that are typically
stored in the "any attribute" of an ISO-19770-2:2015 in XML
representation. These are covered in the main body of this
document.
o the inclusion of extension points in the CoSWID data definition
that allow for additional uses of CoSWID tags that go beyond the
original scope of ISO-19770-2:2015 tags. These are covered in
appendices to this document.
1.2. Requirements Notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in RFC
2119, BCP 14 [RFC2119].
2. Concise SWID Data Definition
The following is a CDDL representation of the ISO-19770-2:2015 [SWID]
XML schema definition of SWID tags. This representation includes
every SWID tag fields and attribute and thus supports all SWID tag
use cases. The CamelCase notation used in the XML schema definition
is changed to a hyphen-separated notation (e.g. ResourceCollection
is named resource-collection in the CoSWID data definition). This
deviation from the original notation used in the XML representation
reduces ambiguity when referencing certain attributes in
corresponding textual descriptions. An attribute referred by its
name in CamelCase notation explicitly relates to XML SWID tags, an
attribute referred by its name in hyphen-separated notation
explicitly relates to CoSWID tags. This approach simplifies the
composition of further work that reference both XML SWID and CoSWID
documents.
Human-readable names of members in the CDDL data definition are
mapped to integer indices via a block of rules at the bottom of the
definition. The 66 character strings of the SWID vocabulary that
would have to be stored or transported in full if using the original
vocabulary are replaced.
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Concise Software Identifiers are tailored to be used in the domain of
constrained-node networks. A typical endpoint is capable of storing
the CoSWID tag of installed software, a constrained-node might lack
that capability. CoSWID address these constraints and the
corresponding specification is augmented to retain their usefulness
in the thing-2-thing domain. Specific examples include, but are not
limited to limiting the scope of hash algorithms to the IANA Named
Information tables or including firmware attributes addressing
devices that do not necessarily provide a file-system to store a
CoSWID tag in.
In order to create a valid CoSWID document the structure of the
corresponding CBOR message MUST adhere to the following CDDL data
definition.
<CODE BEGINS>
concise-software-identity = {
global-attributes,
? entity-entry,
? payload-xor-evidence-entry,
? link-entry,
? software-meta-entry,
; ? payload-entry,
? any-element-entry,
? corpus,
? patch,
? media,
swid-name,
? supplemental,
tag-id,
? tag-version,
? software-version,
? version-scheme,
}
any-uri = text
label = text / int
any-attribute = (
label => text / int / [ 2* text ] / [ 2* int ]
)
any-element-map = {
global-attributes,
* label => any-element-map / [ 2* any-element-map ],
}
global-attributes = (
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? lang,
* any-attribute,
)
resource-collection = (
? directory-entry,
? file-entry,
? process-entry,
? resource-entry
* $$resource-extension
)
file = {
filesystem-item,
? size,
? file-version,
? file-hash,
}
filesystem-item = (
global-attributes,
? key,
? location,
fs-name,
? root,
)
directory = {
filesystem-item,
path-elements,
}
process = {
global-attributes,
process-name,
? pid,
}
resource = {
global-attributes,
type,
}
entity = {
global-attributes,
extended-data,
entity-name,
? reg-id,
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role,
? thumbprint,
}
evidence = {
global-attributes,
resource-collection,
? date,
? device-id,
}
link = {
global-attributes,
? artifact,
href,
? media-type,
? ownership,
rel,
? type,
? use,
}
software-meta = {
global-attributes,
? activation-status,
? channel-type,
? colloquial-version,
? description,
? edition,
? entitlement-data-required,
? entitlement-key,
? generator,
? persistent-id,
? product,
? product-family,
? revision,
? summary,
? unspsc-code,
? unspsc-version,
}
payload = {
global-attributes,
resource-collection,
}
payload-xor-evidence-entry = ((3: evidence) // (6: payload))
tag-id = (0: text)
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swid-name = (1: text)
entity-entry = (2: entity / [ 2* entity ])
evidence-entry = (3: evidence)
link-entry = (4: link / [ 2* link ])
software-meta-entry = (5: software-meta / [ 2* software-meta ])
payload-entry = (6: payload)
any-element-entry = (7: any-element-map / [ 2* any-element-map ])
corpus = (8: bool)
patch = (9: bool)
media = (10: text)
supplemental = (11: bool)
tag-version = (12: integer)
software-version = (13: text)
version-scheme = (14: text)
lang = (15: text)
directory-entry = (16: directory / [ 2* directory ])
file-entry = (17: file / [ 2* file ])
process-entry = (18: process / [ 2* process ])
resource-entry = (19: resource / [ 2* resource ])
size = (20: integer)
file-version = (21: text)
key = (22: bool)
location = (23: text)
fs-name = (24: text)
root = (25: text)
path-elements = (26: { * file-entry,
* directory-entry,
}
)
process-name = (27: text)
pid = (28: integer)
type = (29: text)
extended-data = (30: any-element-map / [ 2* any-element-map ])
entity-name = (31: text)
reg-id = (32: any-uri)
role = (33: text / [2* text])
thumbprint = (34: text)
date = (35: time)
device-id = (36: text)
artifact = (37: text)
href = (38: any-uri)
ownership = (39: "shared" / "private" / "abandon")
rel = (40: text)
media-type = (41: text)
use = (42: "optional" / "required" / "recommended")
activation-status = (43: text)
channel-type = (44: text)
colloquial-version = (45: text)
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description = (46: text)
edition = (47: text)
entitlement-data-required = (48: bool)
entitlement-key = (49: text)
generator = (50: text)
persistent-id = (51: text)
product = (52: text)
product-family = (53: text)
revision = (54: text)
summary = (55: text)
unspsc-code = (56: text)
unspsc-version = (57: text)
file-hash = (58: [ hash-alg-id: int,
hash-value: bstr,
]
)
<CODE ENDS>
3. Description of the SWID Attribute Vocabulary Definition
Yet to be written still...
4. IANA Considerations
This document will include requests to IANA:
o Integer indices for SWID content attributes and information
elements.
o Content-Type for CoAP to be used in COSE.
5. Security Considerations
SWID tags contain public information about software products and, as
such, do not need to be protected against disclosure on an endpoint.
Similarly, SWID tags are intended to be easily discoverable by
applications and users on an endpoint in order to make it easy to
identify and collect all of an endpoint's SWID tags. As such, any
security considerations regarding SWID tags focus on the application
of SWID tags to address security challenges, and the possible
disclosure of the results of those applications.
A signed SWID tag whose signature is intact can be relied upon to be
unchanged since it was signed. If the SWID tag was created by the
software author, this generally means that it has undergone no change
since the software application with which the tag is associated was
installed. By implication, this means that the signed tag reflects
the software author's understanding of the details of that software
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product. This can be useful assurance when the information in the
tag needs to be trusted, such as when the tag is being used to convey
golden measurements. By contrast, the data contained in unsigned
tags cannot be trusted to be unmodified.
SWID tags are designed to be easily added and removed from an
endpoint along with the installation or removal of software products.
On endpoints where addition or removal of software products is
tightly controlled, the addition or removal of SWID tags can be
similarly controlled. On more open systems, where many users can
manage the software inventory, SWID tags may be easier to add or
remove. On such systems, it may be possible to add or remove SWID
tags in a way that does not reflect the actual presence or absence of
corresponding software products. Similarly, not all software
products automatically install SWID tags, so products may be present
on an endpoint without providing a corresponding SWID tag. As such,
any collection of SWID tags cannot automatically be assumed to
represent either a complete or fully accurate representation of the
software inventory of the endpoint. However, especially on devices
that more strictly control the ability to add or remove applications,
SWID tags are an easy way to provide an preliminary understanding of
that endpoint's software inventory.
Any report of an endpoint's SWID tag collection provides information
about the software inventory of that endpoint. If such a report is
exposed to an attacker, this can tell them which software products
and versions thereof are present on the endpoint. By examining this
list, the attacker might learn of the presence of applications that
are vulnerable to certain types of attacks. As noted earlier, SWID
tags are designed to be easily discoverable by an endpoint, but this
does not present a significant risk since an attacker would already
need to have access to the endpoint to view that information.
However, when the endpoint transmits its software inventory to
another party, or that inventory is stored on a server for later
analysis, this can potentially expose this information to attackers
who do not yet have access to the endpoint. As such, it is important
to protect the confidentiality of SWID tag information that has been
collected from an endpoint, not because those tags individually
contain sensitive information, but because the collection of SWID
tags and their association with an endpoint reveals information about
that endpoint's attack surface.
Finally, both the ISO-19770-2:2015 XML schema definition and the
Concise SWID data definition allow for the construction of "infinite"
SWID tags or SWID tags that contain malicious content with the intend
if creating non-deterministic states during validation or processing
of SWID tags. While software product vendors are unlikely to do
this, SWID tags can be created by any party and the SWID tags
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collected from an endpoint could contain a mixture of vendor and non-
vendor created tags. For this reason, tools that consume SWID tags
ought to treat the tag contents as potentially malicious and should
employ input sanitizing on the tags they ingest.
6. Acknowledgements
7. Change Log
Changes from version 00 to version 01:
o Added CWT usage for absolute SWID paths on a device
o Fixed cardinality of type-choices including arrays
o Included first iteration of firmware resource-collection
Changes since adopted as a WG I-D -00:
o Removed redundant any-attributes originating from the ISO-
19770-2:2015 XML schema definition
o Fixed broken multi-map members
o Introduced a more restrictive item (any-element-map) to represent
custom maps, increased restriction on types for the any-attribute,
accordingly
o Fixed X.1520 reference
o Minor type changes of some attributes (e.g. NMTOKENS)
o Added semantic differentiation of various name types (e,g. fs-
name)
Changes from version 00 to version 01:
o Ambiguity between evidence and payload eliminated by introducing
explicit members (while still
o allowing for "empty" SWID tags)
o Added a relatively restrictive COSE envelope using cose_sign1 to
define signed CoSWID (single signer only, at the moment)
o Added a definition how to encode hashes that can be stored in the
any-member using existing IANA tables to reference hash-algorithms
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Changes from version 01 to version 02:
o Enforced a more strict separation between the core CoSWID
definition and additional usage by moving content to corresponding
appendices.
o Removed artifacts inherited from the reference schema provided by
ISO (e.g. NMTOKEN(S))
o Simplified the core data definition by removing group and type
choices where possible
o Minor reordering of map members
o Added a first extension point to address requested flexibility for
extensions beyond the any-element
8. Contributors
9. References
9.1. Normative References
[I-D.ietf-ace-cbor-web-token]
Jones, M., Wahlstroem, E., Erdtman, S., and H. Tschofenig,
"CBOR Web Token (CWT)", draft-ietf-ace-cbor-web-token-10
(work in progress), December 2017.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC4108] Housley, R., "Using Cryptographic Message Syntax (CMS) to
Protect Firmware Packages", RFC 4108,
DOI 10.17487/RFC4108, August 2005,
<https://www.rfc-editor.org/info/rfc4108>.
[RFC4949] Shirey, R., "Internet Security Glossary, Version 2",
FYI 36, RFC 4949, DOI 10.17487/RFC4949, August 2007,
<https://www.rfc-editor.org/info/rfc4949>.
[RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object
Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049,
October 2013, <https://www.rfc-editor.org/info/rfc7049>.
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[RFC7228] Bormann, C., Ersue, M., and A. Keranen, "Terminology for
Constrained-Node Networks", RFC 7228,
DOI 10.17487/RFC7228, May 2014,
<https://www.rfc-editor.org/info/rfc7228>.
[RFC8152] Schaad, J., "CBOR Object Signing and Encryption (COSE)",
RFC 8152, DOI 10.17487/RFC8152, July 2017,
<https://www.rfc-editor.org/info/rfc8152>.
[SAM] "Information technology - Software asset management - Part
5: Overview and vocabulary", ISO/IEC 19770-5:2013,
November 2013.
[SWID] "Information technology - Software asset management - Part
2: Software identification tag'", ISO/IEC 19770-2:2015,
October 2015.
[X.1520] "Recommendation ITU-T X.1520 (2014), Common
vulnerabilities and exposures", April 2011.
9.2. Informative References
[I-D.banghart-sacm-rolie-softwaredescriptor]
Waltermire, D. and S. Banghart, "Definition of the ROLIE
Software Descriptor Extension", draft-banghart-sacm-rolie-
softwaredescriptor-01 (work in progress), May 2017.
[I-D.birkholz-tuda]
Fuchs, A., Birkholz, H., McDonald, I., and C. Bormann,
"Time-Based Uni-Directional Attestation", draft-birkholz-
tuda-04 (work in progress), March 2017.
[I-D.ietf-cbor-cddl]
Birkholz, H., Vigano, C., and C. Bormann, "Concise data
definition language (CDDL): a notational convention to
express CBOR data structures", draft-ietf-cbor-cddl-00
(work in progress), July 2017.
[I-D.ietf-sacm-terminology]
Birkholz, H., Lu, J., Strassner, J., Cam-Winget, N., and
A. Montville, "Security Automation and Continuous
Monitoring (SACM) Terminology", draft-ietf-sacm-
terminology-14 (work in progress), December 2017.
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Appendix A. Explicit file-hash Type Used in Concise SWID Tags (label
56)
CoSWID add explicit support for the representation of file-hashes
using algorithms that are registered at the Named Information Hash
Algorithm Registry via the file-hash member (label 56).
file-hash = (56: [ hash-alg-id: int, hash-value: bstr ] )
The number used as a value for hash-alg-id MUST refer the ID in the
Named Information Hash Algorithm table; other hash algorithms MUST
NOT be used. The hash-value MUST represent the raw hash value of the
file-entry the file-hash type is included in.
Appendix B. CoSWID Attributes for Firmware (label 57)
The ISO-19770-2:2015 specification of SWID tags assumes the existence
of a file system a software component is installed and stored in. In
the case of constrained-node networks [RFC7228] or network equipment
this assumption might not apply. Concise software instances in the
form of (modular) firmware are often stored directly on a block
device that is a hardware component of the constrained-node or
network equipment. Multiple differentiable block devices or
segmented block devices that contain parts of modular firmware
components (potentially each with their own instance version) are
already common at the time of this writing.
The optional attributes that annotate a firmware package address
specific characteristics of pieces of firmware stored directly on a
block-device in contrast to software deployed in a file-system. In
essence, trees of relative path-elements expressed by the directory
and file structure in CoSWID tags are typically unable to represent
the location of a firmware on a constrained-node (small thing). The
composite nature of firmware and also the actual composition of small
things require a set of attributes to address the identification of
the correct component in a composite thing for each individual piece
of firmware. A single component also potentially requires a number
of distinct firmware parts that might depend on each other
(versions). These dependencies can be limited to the scope of the
component itself or extend to the scope of a larger composite device.
In addition, it might not be possible (or feasible) to store a CoSWID
tag document (permanently) on a small thing along with the
corresponding piece of firmware.
To address the specific characteristics of firmware, the extension
point "$$resource-extension" is used to allow for an additional type
of resource description--firmware-entry--thereby increasing the self-
descriptiveness and flexibility of CoSWID. The optional use of the
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extension point "$$resource-extension" in respect to firmware MUST
adhere to the following CDDL data definition.
<CODE BEGINS>
$$resource-extension //= (firmware-entry,)
firmware = {
firmware-name, ; inherited from RFC4108
? firmware-version,
? firmware-package-identifier, ; inherited from RFC4108
? dependency, ; inherited from RFC4108
? component-index, ; equivalent to RFC4108 fwPkgType
? block-device-identifier,
? target-hardware-identifier, ; an RFC4108 alternative to model-label
model-label,
? firmware-hash, ; a hash for a single, incl. NI hash-algo index
? firmware-package, ; RCF4108, experimental, this is an actual firmware blob!
}
firmware-entry = (57: firmware / [ 2* firmware ])
firmware-hash = (58: [ hash-alg-id: int,
hash-value: bstr,
]
)
firmware-name = (59 : text)
firmware-version = (60 : text / int)
component-index = (61 : int)
model-label = (62: text / int)
block-device-identifier = (63 : text / int)
firmware-package = (64: bstr)
firmware-package-identifier = (65: text)
target-hardware-identifier = (66: text)
dependency = (67: { ? firmware-name,
? firmware-version,
? firmware-package-identifier,
}
)
<CODE ENDS>
The members of the firmware group that constitutes the content of the
firmware-entry is based on the metadata about firmware defined in
[RFC4108]. As with every semantic differentiation that is supported
by the resource-collection type, the use of firmware-entry is
optional. It is REQUIRED not to instantiate more than one firmware-
entry, as the firmware group is used in a map and therefore only
allows for unique labels.
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The optional cms-firmware-package member allows to include the actual
firmware in the CoSWID tag that also expresses its metadata as a
byte-string. This option enables a CoSWID tag to be used as a
container or wrapper that composes both firmware and its metadata in
a single document (which again can be signed, encrypted and/or
compressed). In consequence, a CoSWID tag about firmware can be
conveyed as an identifying document across endpoints or used as a
reference integrity measurement as usual. Alternatively, it can also
convey an actual piece of firmware, serve its intended purpose as a
SWID tag and then - due to the lack of a location to store it - be
discarded.
Appendix C. Signed Concise SWID Tags using COSE
SWID tags, as defined in the ISO-19770-2:2015 XML schema, can include
cryptographic signatures to protect the integrity of the SWID tag.
In general, tags are signed by the tag creator (typically, although
not exclusively, the vendor of the software product that the SWID tag
identifies). Cryptographic signatures can make any modification of
the tag detectable, which is especially important if the integrity of
the tag is important, such as when the tag is providing reference
integrity measurments for files.
The ISO-19770-2:2015 XML schema uses XML DSIG to support
cryptographic signatures. CoSWID tags require a different signature
scheme than this. COSE (CBOR Object Signing and Encryption) provides
the required mechanism [RFC8152]. Concise SWID can be wrapped in a
COSE Single Signer Data Object (cose-sign1) that contains a single
signature. The following CDDL defines a more restrictive subset of
header attributes allowed by COSE tailored to suit the requirements
of Concise SWID.
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<CODE BEGINS>
signed-coswid = #6.997(COSE-Sign1-coswid) ; see TBS7 in current COSE I-D
label = int / tstr ; see COSE I-D 1.4.
values = any ; see COSE I-D 1.4.
unprotected-signed-coswid-header = {
1 => int, ; algorithm identifier
3 => "application/coswid", ; request for CoAP IANA registry to become an int
* label => values,
}
protected-signed-coswid-header = {
4 => bstr, ; key identifier
* label => values,
}
COSE-Sign1-coswid = [
protected: bstr .cbor protected-signed-coswid-header,
unprotected: unprotected-signed-coswid-header,
payload: bstr .cbor concise-software-identity,
signature: bstr,
]
<CODE ENDS>
Appendix D. CoSWID used as Reference Integrity Measurements (CoSWID
RIM)
A vendor supplied signed CoSWID tag that includes hash-values for the
files that compose a software component can be used as a RIM
(reference integrity measurement). A RIM is a type of declarative
guidance that can be used to assert the compliance of an endpoint by
assessing the installed software. In the context of remote
attestation based on an attestation via hardware rooted trust, a
verifier can appraise the integrity of the conveyed measurements of
software components using a CoSWID RIM provided by a source, such as
[I-D.banghart-sacm-rolie-softwaredescriptor].
RIM Manifests (RIMM): A group of SWID tags about the same
(sub-)system, system entity, or (sub-)component (compare
[RFC4949]). A RIMM manifest is a distinct document that is
typically conveyed en-block and constitutes declarative guidance
in respect to a specific (target) endpoint (compare
[I-D.ietf-sacm-terminology]).
If multiple CoSWID compose a RIMM, the following CDDL data definition
SHOULD be used.
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RIMM = [ + concise-software-identity / signed-coswid ]
Appendix E. CBOR Web Token for Concise SWID Tags
A typical requirement regarding specific instantiations of endpoints
- and, as a result, specific instantiations of software components -
is a representation of the absolute path of a CoSWID tag document in
a file system in order to derive absolute paths of files represented
in the corresponding CoSWID tag. The absolute path of an evidence
CoSWID tag can be included as a claim in the header of a CBOR Web
Token [I-D.ietf-ace-cbor-web-token]. Depending on the source of the
token, the claim can be in the protected or unprotected header
portion.
<CODE BEGINS>
CDDL TBD
<CODE ENDS>
Appendix F. Group Definitions
These groups are intermediate CDDL data definitions that are reused
in several items in the CoSWID CDDL data definition.
o resource-collection group: A list of items both used in evidence
(discovered by an inventory process) and payload (installed in a
system entity) content of a CoSWID tag document to structure and
differentiate the content of specific CoSWID tag types. Potential
content includes directories, files, processes, resources or
firmwares.
o filesystem group: A list of items both used in representing the
nodes of a file-system hierarchy, i.e. directory items that allow
one or more directories to be defined in the file structure, and
file items that allow one or more files to be specified for a
given location.
o global-attributes: A list of items including an optional language
definition to support the processing of text-string values and an
unbounded set of any-attribute items.
o any-attribute: A specific rule providing a restricted frame to
include arbitrary information via members that constitute key
value(s) pairs where both keys and values can be integers or text-
strings.
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Appendix G. Item Definitions
This Appendix includes the description of every primitive and non-
primitive type the concise-software-identifier is composed of. Every
integer label included at the end of the CDDL data definition is
addressed in this section.
1. tag-id: An identifier uniquely referencing a (composite)
software component. The tag identifier is intended to be
globally unique. There are no strict guidelines on how this
identifier is structured, but examples include a 16 byte GUID
(e.g. class 4 UUID).
2. swid-name: This item provides the software component name as it
would typically be referenced. For example, what would be seen
in the add/remove dialog on a Windows device, or what is
specified as the name of a packaged software product or a patch
identifier name on a Linux device.
3. entity: Specifies the organizations related to the software
component referenced by this CoSWID tag.
4. evidence: This item is used to provide results from a scan of a
system where software that does not have a CoSWID tag is
discovered. This information is not provided by the software-
creator, and is instead created when a system is being scanned
and the evidence for why software is believed to be installed on
the device is provided in the evidence item.
5. link: A reference to any another item (can include details that
are related to the CoSWID tag such as details on where specific
resources can be found, e.g. vulnerability database
associations, ROLIE feeds, MUD files, etc). This is modeled
directly to match the HTML [LINK] element; it is critical for
streamlining software discovery scenarios to ensure their
consistency.
6. software-meta: An open-ended collection of key/value data
related to this CoSWID. The attributes included in this Element
are predefined attributes to ensure common usage across the
industry. The schema allows for any additional attribute to be
included in a CoSWID tag, though it is recommended that industry
norms for new attributes are defined and followed to the degree
possible.
7. payload: The items that may be installed on a system entity when
the software component is installed. Note that payload may be a
superset of the items installed and - depending on optimization
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mechanisms in respect to that system entity - may or may not
include every item that could be created or executed on the
corresponding system entitiy when software components are
installed. In general, payload will be used to indicate the
files that may be installed with a software component.
Therefore payload will often be a superset of those files (i.e.
if a particular optional sub-component is not installed, the
files associated with that software component may be included in
payload, but not installed in the system entity).
8. any-element: A default map that can contain arbitrary map
members and even nested maps (which would be also any-elements).
In essence, the any-element allows items not defined in this
CDDL data definition to be included in a Concise Software
Identifier.
9. corpus: Set to true, if this attribute specifies that this SWID
tag is a collection of information that describes the pre-
installation data of software component.
10. patch: A set of files that is intended to modify an existing set
of files (including configuration files, scripts and
corresponding environment variables that are create by the OS
for the runtime environment) that composes a software component.
A software component patch does neither alter the version number
(see 13) nor the release details (descriptive english text, see
44) of a software components. [revision 52?]. If a Concise SWID
tag is a patch, it MUST contain the patch item and its value
MUST be set to true. It is recommended but not required to
include a rel(ation) item in a patch CoSWID. If a CoSWID
includes a patch member, but not a rel member, it is implied
that it SHOULD be installed independently of any other CoSWID
tag document - even if an effective but not explicit
relationship exists.
11. media: This text value is a hint to the tag consumer to
understand what this SWID tag applies to. This item can also be
included in the link item to represent a attributes defined by
the W3C Media Queries Recommendation (see http://www.w3.org/TR/
css3-mediaqueries/). A hint to the consumer of the link to what
the target item is applicable for.
12. supplemental: Specifies that this tag provides supplemental tag
data that can be merged with primary tag data to create a
complete record of the software information. Supplemental tags
will often be provided at install time and may be provided by
different entities (such as the tag consumer, or a Value Added
Reseller).
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13. tag-version: This item indicates if a specific release of a
software component has more than one tag that can represent that
specific release. This may be the case if a CoSWID tag producer
creates and releases an incorrect tag that they subsequently
want to fix, but with no underlying changes to the product the
CoSWID tag represents. This could happen if, for example, a
patch is distributed that has a link reference that does not
cover all the various software releases it can patch. A newer
CoSWID tag for that patch can be generated and the tag-version
value incremented to indicate that the data is updated.
14. software-version: Underlying development version for the
software component.
15. version-scheme: Scheme used for the version number. Valid
enumerations are : * alphanumeric: strictly a string, sorting
alphanumerically * decimal: a floating point number (i.e., 1.25
is less than 1.3 ) * multipartnumeric: numbers separated via
dots, where the numbers are * interpreted as integers (ie, 1.2.3
, 1.4.5.6 , 1.2.3.4.5.6.7). This string * convention is similar
to OIDs. * multipartnumeric+suffix: numbers separated via dots,
where the numbers are * interpreted as integers with an
additional string suffix (e.g., 1.2.3a). * semver: a string as
defined by the semver.org spec [FiXME: reference] * unknown: the
last resort choice, no attempt should be made to order these
16. lang: An RFC5646 conferment language tag or corresponding IANA
index integer.
17. directory: A directory item allows one or more directories to be
defined in the file structure.
18. file: A file element that allows one or more files to be
specified for a given location.
19. process: Provides process (software component in execution)
information for data that will show up in a devices process
table.
20. resource: A set of items that can be used to provide arbitrary
resource information about an application installed on a system
entity, or evidence collected from a system entity.
21. size: The file size in bytes of the file.
22. file-version The file version.
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23. key: Files that are considered important or required for the use
of a software component. Typical key files would be those
which, if not available on a system entity, would cause the
software component not to execute or function properly. Key
files will typically be used to validate that a software
component referenced by the CoSWID tag document is actually
installed on a specific system entity.
24. location: The directory or location where a file was found or
can expected to be located. This text-string is intended to
include the filename itself. This SHOULD be the relative path
represented by the root item.
25. fs-name: The file name or directory name without any path
characters.
26. root: A system-specific root folder that the location item is an
offset from. If this is not specified the assumption is the
root is the same folder as the location of the CoSWID tag. The
text-string value represents a path expression relative to the
CoSWID tag document location in the (composite) file-system
hierarchy.
27. path-elements: Provides the ability to apply a directory
structure to the path expressions for files defined in a payload
or evidence item.
28. process-name: The process name as it will be found in the system
entity's process table.
29. pid: The process ID for the process in execution that can be
included in the process item as part of an evidence tag.
30. type: The type of resource represented via a text-string
(typically, registry-key, port or root-uri)
31. extended-data: An open-ended collection of elements that can be
used to attach arbitrary metadata to an entity item.
32. entity-name: The text-string name of the organization claiming a
particular role in the CoSWID tag.
33. reg-id: The registration id is intended to uniquely identify a
naming authority in a given scope (e.g. global, organization,
vendor, customer, administrative domain, etc.) that is implied
by the referenced naming authority. The value of an
registration ID MUST be a RFC 3986 URI. The scope SHOULD be the
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scope of an organization. In a given scope, the registration id
MUST be used consistently.
34. role: The relationship between this organization and this tag.
The role of tag creator is required for every CoSWID tag. The
role of an entity may include any role value, but the per-
defined roles include: "aggregator", "distributor", "licensor",
"software-creator", "tag-creator". The enumerations of this
will include a request to IANA in order to be reference-able via
an integer index.
35. thumbprint: This value provides a hexadecimal string that
contains a hash (i.e. the thumbprint) of the signing entities
certificate [s] [FIXME: this requires the same structure as
file-hash?].
36. date: The sate and time evidence represented by an evidence item
was gathered.
37. device-id: A text-string identifier for a device evidence was
gathered from.
38. artifact: For installation media (rel="installation-media") -
dictates the canonical name for the file. Items with the same
artifact name should be considered mirrors of each other (so
download from wherever works).
39. href: The link to the item being referenced. The href can point
to several different things, and can be any of the following: *
a relative uri (no scheme), which is interpreted depending on
context (for example, "./folder/supplemental.coswid") * a
physical file location with any system-acceptable URI scheme
(e.g., file:// http:// https:// ftp://) * an URI with "coswid:"
as the scheme, which refers to another CoSWID by tag-id. This
URI would need to be resolved in the context of the system by
software that can lookup other CoSWID tags (for example, *
"coswid:2df9de35-0aff-4a86-ace6-f7dddd1ade4c"). an URI with
"swidpath:" as the scheme, which refers to another CoSIWD via an
XPATH query. This URI would need to be resolved in the context
of the system entity via dedicated software components that can
lookup other CoSWID tags and select the appropriate tag based on
an XPATH query. Examples include: *
swidpath://SoftwareIdentity[Entity/@regid='http://contoso.com']
would * retrieve all CoSWID tags that include an entity where
the regid was * "Contoso". * swidpath://SoftwareIdentity[Meta/@
persistentId='b0c55172-38e9-4e36-be86-92206ad8eddb'] * would
retrieve CoSWID tags that matched the persistent-id. See XPATH
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query standard : http://www.w3.org/TR/xpath20/ [FIXME: Concise
XPATH representation is covered in the YANG-CBOR I-D]
40. ownership: Determines the relative strength of ownership of the
software components. Valid enumerations are: abandon, private,
shared
41. rel: The relationship between this CoSWID and the target file.
Relationships can be identified by referencing the IANA
registration library: https://www.iana.org/assignments/link-
relations/link-relations.xhtml.
42. media-type: The IANA MediaType for the target file; this
provides the consumer with intelligence of what to expect. See
http://www.iana.org/assignments/media-types/media-types.xhtml
for more details on link type.
43. use: Determines if the target software is a hard requirement or
not. Valid enumerations are: required, recommended, optional,
44. activation-status: Identification of the activation status of
this software title (e.g. Trial, Serialized, Licensed,
Unlicensed, etc). Typically, this is used in supplemental tags.
45. channel-type: Provides information on which channel this
particular software was targeted for (e.g. Volume, Retail, OEM,
Academic, etc). Typically used in supplemental tags.
46. colloquial-version: The informal or colloquial version of the
product (i.e. 2013). Note that this version may be the same
through multiple releases of a software product where the
version specified in entity is much more specific and will
change for each software release. Note that this representation
of version is typically used to identify a group of specific
software releases that are part of the same release/support
infrastructure (i.e. Fabrikam Office 2013). This version is
used for string comparisons only and is not compared to be an
earlier or later release (that is done via the entity version
[FIXME: consistency).
47. description: A longer, detailed description of the software.
This description can be multiple sentences (differentiated from
summary, which is a very short, one-sentence description).
48. edition: The variation of the product (Extended, Enterprise,
Professional, Standard etc).
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49. entitlement-data-required: An indicator to determine if there
should be accompanying proof of entitlement when a software
license reconciliation is completed.
50. entitlement-key: A vendor-specific textual key that can be used
to reconcile the validity of an entitlement. (e.g. serial
number, product or license key).
51. generator: The name of the software tool that created a CoSWID
tag. This item is typically used if tags are created on the fly
or via a catalog-based analysis for data found on a computing
device.
52. persistent-id: A GUID used to represent products installed where
the product are related, but may be different versions. For
example, an "upgradeCode" (see http://msdn.microsoft.com/en-
us/library/aa372375(v=vs.85).aspx as an reference for this
example).
53. product: The base name of the product (e.g. [FIXME: what are
appropriate examples?].
54. product-family: The overall product family this software belongs
to. Product family is not used to identify that a product is
part of a suite, but is instead used when a set of products that
are all related may be installed on multiple different devices.
For example, an enterprise backup system may consist of a backup
services, multiple different backup services that support mail
services, databases and ERP systems, as well as individual
software components that backup client system entities. In such
an usage scenario, all software components that are part of the
backup system would have the same product-family name so they
can be grouped together in respect to reporting systems.
55. revision: The informal or colloquial representation of the sub-
version of the given product (ie, SP1, R2, RC1, Beta 2, etc).
Note that the version will provide very exact version details,
the revision is intended for use in environments where reporting
on the informal or colloquial representation of the software is
important (for example, if for a certain business process, an
organization recognizes that it must have, for example
"ServicePack 1" or later of a specific product installed on all
devices, they can use the revision data value to quickly
identify any devices that do not meet this requirement).
Depending on how a software organizations distributes revisions,
this value could be specified in a primary (if distributed as an
upgrade) or supplemental (if distributed as a patch) CoSWID tag.
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56. summary: A short (one-sentence) description of the software.
57. unspsc-code: An 8 digit code that provides UNSPSC classification
of the software product this SWID tag identifies. For more
information see, http://www.unspsc.org/.
58. unspsc-version: The version of the UNSPSC code used to define
the UNSPSC code value. For more information see,
http://www.unspsc.org/.
Authors' Addresses
Henk Birkholz
Fraunhofer SIT
Rheinstrasse 75
Darmstadt 64295
Germany
Email: henk.birkholz@sit.fraunhofer.de
Jessica Fitzgerald-McKay
Department of Defense
9800 Savage Road
Ft. Meade, Maryland
USA
Email: jmfitz2@nsa.gov
Charles Schmidt
The MITRE Corporation
202 Burlington Road
Bedford, Maryland 01730
USA
Email: cmschmidt@mitre.org
David Waltermire
National Institute of Standards and Technology
100 Bureau Drive
Gaithersburg, Maryland 20877
USA
Email: david.waltermire@nist.gov
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