SACM Working Group H. Birkholz
Internet-Draft Fraunhofer SIT
Intended status: Standards Track J. Fitzgerald-McKay
Expires: April 26, 2019 Department of Defense
C. Schmidt
The MITRE Corporation
D. Waltermire
NIST
October 23, 2018
Concise Software Identifiers
draft-ietf-sacm-coswid-07
Abstract
This document defines a concise representation of ISO/IEC
19770-2:2015 Software Identification (SWID) tags that are
interoperable with the XML schema definition of ISO/IEC 19770-2:2015
and augmented for application in Constrained-Node Networks. Next to
the inherent capability of SWID tags to express arbitrary context
information, Concise SWID (CoSWID) tags support the definition of
additional semantics via well-defined data definitions incorporated
by extension points.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on April 26, 2019.
Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. The SWID Tag Lifecycle . . . . . . . . . . . . . . . . . 4
1.2. Concise SWID Extensions . . . . . . . . . . . . . . . . . 6
1.3. Requirements Notation . . . . . . . . . . . . . . . . . . 7
2. Concise SWID Data Definition . . . . . . . . . . . . . . . . 7
2.1. The concise-software-identity Object . . . . . . . . . . 8
2.1.1. Determining the tag type . . . . . . . . . . . . . . 11
2.1.2. concise-software-identity Co-constraints . . . . . . 12
2.2. The global-attributes Group . . . . . . . . . . . . . . . 12
2.3. The any-element-map Entry . . . . . . . . . . . . . . . . 13
2.4. The entity Object . . . . . . . . . . . . . . . . . . . . 13
2.5. The link Object . . . . . . . . . . . . . . . . . . . . . 14
2.6. The software-meta Object . . . . . . . . . . . . . . . . 16
2.7. The Resource Collection Definition . . . . . . . . . . . 19
2.7.1. The hash-entry Array . . . . . . . . . . . . . . . . 19
2.7.2. The resource-collection Group . . . . . . . . . . . . 20
2.7.3. The payload Object . . . . . . . . . . . . . . . . . 22
2.7.4. The evidence Object . . . . . . . . . . . . . . . . . 23
2.8. Full CDDL Definition . . . . . . . . . . . . . . . . . . 24
3. CoSWID Indexed Label Values . . . . . . . . . . . . . . . . . 29
3.1. Version Scheme . . . . . . . . . . . . . . . . . . . . . 29
3.2. Entity Role Values . . . . . . . . . . . . . . . . . . . 29
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 30
4.1. SWID/CoSWID Version Schema Values Registry . . . . . . . 30
4.2. SWID/CoSWID Entity Role Values Registry . . . . . . . . . 31
4.3. Media Type Registration . . . . . . . . . . . . . . . . . 32
4.3.1. swid+cbor Media Type Registration . . . . . . . . . . 32
4.4. CoAP Content-Format Registration . . . . . . . . . . . . 33
4.5. CBOR Tag Registration . . . . . . . . . . . . . . . . . . 34
5. Security Considerations . . . . . . . . . . . . . . . . . . . 34
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 36
7. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 36
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 38
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 38
9.1. Normative References . . . . . . . . . . . . . . . . . . 39
9.2. Informative References . . . . . . . . . . . . . . . . . 40
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Appendix A. CoSWID Attributes for Firmware (label 60) . . . . . 41
Appendix B. Signed Concise SWID Tags using COSE . . . . . . . . 44
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 45
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 software components
installed on 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].
SWID tags, as defined in ISO-19770-2:2015 [SWID], provide a
standardized XML-based record format that identifies and describes a
specific release of a software component. Different software
components, and even different releases of a particular software
component, each have a different SWID tag record associated with
them. SWID tags are meant to be flexible and able to express a broad
set of metadata about a software component.
While there are very few required fields in SWID tags, there are many
optional fields that support different use scenarios. While a SWID
tag consisting of only required fields might be a few hundred bytes
in size, a tag containing many of the optional fields can be many
orders of magnitude larger. Thus, 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. Concise SWID (CoSWID) tags
significantly reduce the amount of data transported as compared to a
typical SWID tag. This reduction is enabled through the use of CBOR,
which maps human-readable labels of that content to more concise
integer labels (indices). The use of CBOR to express SWID
information in CoSWID tags allows both CoSWID and SWID tags to be
part of an enterprise security solution for a wider range of
endpoints and environments.
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1.1. The SWID Tag Lifecycle
In addition to defining the format of a SWID tag record, ISO/IEC
19770-2:2015 defines requirements concerning the SWID tag lifecycle.
Specifically, when a software component 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/IEC 19770-2:2015
describes a system wherein there is a correspondence between the set
of installed software components on an endpoint, and the presence of
the correspondingsponding SWID tags for these components on that
endpoint. CoSWIDs share the same lifecycle requirements as a SWID
tag.
The following is an excerpt (with some modifications and reordering)
from NIST Interagency Report (NISTIR) 8060: Guidelines for the
Creation of Interoperable SWID Tags [SWID-GUIDANCE], which describes
the tag types used within the lifecycle defined in ISO-19770-2:2015.
The SWID specification defines four types of SWID tags: primary,
patch, corpus, and supplemental.
1. Primary Tag - A SWID or CoSWID tag that identifies and describes
a software component is installed on a computing device.
2. Patch Tag - A SWID or CoSWID tag that identifies and describes an
installed patch which has made incremental changes to a software
component installed on a computing device.
3. Corpus Tag - A SWID or CoSWID tag that identifies and describes
an installable software component in its pre-installation state.
A corpus tag can be used to represent metadata about an
installation package or installer for a software component, a
software update, or a patch.
4. Supplemental Tag - A SWID or CoSWID tag that allows additional
information to be associated with a referenced SWID tag. This
helps to ensure that SWID Primary and Patch Tags provided by a
software provider are not modified by software management tools,
while allowing these tools to provide their own software
metadata.
Corpus, primary, and patch tags have similar functions in that
they describe the existence and/or presence of different types of
software (e.g., software installers, software installations,
software patches), and, potentially, different states of software
components. In contrast, supplemental tags furnish additional
information not contained in corpus, primary, or patch tags. All
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four tag types come into play at various points in the software
lifecycle, and support software management processes that depend
on the ability to accurately determine where each software
component is in its lifecycle.
+------------+
v |
Installation Product Product Product Product
Media -> Installed -> Patched -> Upgraded -> Removed
Deployed
Corpus Primary Primary xPrimary xPrimary
Supplemental Supplemental xSupplemental xSuplemental
Patch xPatch
Primary
Supplemental
Figure 1: Use of Tag Types in the Software Lifecycle
Figure 1 illustrates the steps in the software lifecycle and the
relationships among those lifecycle events supported by the four
types of SWID and CoSWID tags, as follows:
* Software Deployment. Before the software component is
installed (i.e., pre-installation), and while the product is
being deployed, a corpus tag provides information about the
installation files and distribution media (e.g., CD/DVD,
distribution package).
* Software Installation. A primary tag will be installed with
the software component (or subsequently created) to uniquely
identify and describe the software component. Supplemental
tags are created to augment primary tags with additional site-
specific or extended information. While not illustrated in the
figure, patch tags may also be installed during software
installation to provide information about software fixes
deployed along with the base software installation.
* Software Patching. When a new patch is applied to the software
component, a new patch tag is provided, supplying details about
the patch and its dependencies. While not illustrated in the
figure, a corpus tag can also provide information about the
patch installer, and patching dependencies that need to be
installed before the patch.
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* Software Upgrading. As a software component is upgraded to a
new version, new primary and supplemental tags replace existing
tags, enabling timely and accurate tracking of updates to
software inventory. While not illustrated in the figure, a
corpus tag can also provide information about the upgrade
installer, and dependencies that need to be installed before
the upgrade.
* Software Removal. Upon removal of the software component,
relevant SWID tags are removed. This removal event can trigger
timely updates to software inventory reflecting the removal of
the product and any associated patch or supplemental tags.
Note: While not fully illustrated in the figure, supplemental tags
can be associated with any corpus, primary, or patch tag to provide
additional metadata about an installer, installed software, or
installed patch respectively.
Each of the different SWID and CoSWID tag types provide different
sets of information. For example, a "corpus tag" is used to describe
a software component's installation image on an installation media,
while a "patch tag" is meant to describe a patch that modifies some
other software component.
1.2. Concise SWID Extensions
This document defines the CoSWID format, a more concise
representation of SWID information 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
CoSWID 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, are mapped to more concise labels represented as small
integer values. 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/
IEC 19770-2:2015.
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 Section 2.2 and Section 2.3
of this document.
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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
Section 2.7.3 and Section 2.7.4.
1.3. 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 for a CoSWID tag. This CDDL
represetation is intended to be parallel to the XML schema definition
in the ISO/IEC 19770-2:2015 [SWID] specification, allowing both SWID
and CoSWID tags to represent a common set of SWID information and to
support all SWID tag use cases. To achieve this end, the CDDL
representation includes every SWID tag field and attribute. 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 67 character strings of the SWID vocabulary that
would have to be stored or transported in full if using the original
vocabulary are replaced.
In CBOR, an array is encoded using bytes that identify the array, and
the array's length or stop point (see [RFC7049]). To make items that
support 1 or more values, the following CDDL notion is used.
_name_ = (_label_: _data_ / [ 2* _data_ ])
The CDDL above allows for a more effecient CBOR encoding of the data
when a single value is used by avoiding the need to first encode the
array. An array is used for two or more values. This modeling
pattern is used frequently in the CoSWID CDDL data definition in such
cases.
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The following subsections describe the different parts of the CoSWID
model.
2.1. The concise-software-identity Object
The CDDL for the main concise-software-identity object is as follows:
concise-software-identity = {
global-attributes,
tag-id,
tag-version,
? corpus,
? patch,
? supplemental,
swid-name,
? software-version,
? version-scheme,
? media,
? software-meta-entry,
? entity-entry,
? link-entry,
? ( payload-entry / evidence-entry ),
? any-element-entry,
}
tag-id = (0: text)
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)
The following describes each child item of the concise-software-
identity object model.
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. Described in Section 2.2.
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o tag-id (label 0): An textual identifier uniquely referencing a
(composite) software component. The tag identifier MUST 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) [RFC4122].
o tag-version (label 12): An integer value that indicates if a
specific release of a software component has more than one tag
that can represent that specific release. Typically, the initial
value of this field is set to 0, and the value is monotonically
increased for subsequent tags produced for the same software
component release. This item is used when a CoSWID tag producer
creates and releases an incorrect tag that they subsequently want
to fix, but no underlying changes have been made 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.
o corpus (label 8): A boolean value that indicates if the tag
identifies and describes an installable software component in its
pre-installation state. Installable software includes a
installation package or installer for a software component, a
software update, or a patch. If the CoSWID tag represents
installable software, the corpus item MUST be set to "true". If
not provided the default value MUST be considered "false".
o patch (label 9): A boolean value that indicates if the tag
identifies and describes an installed patch which has made
incremental changes to a software component installed on a
computing device. Typically, an installed patch has made a set of
file modifications to pre-installed software, and does not alter
the version number or the descriptive metadata of an installed
software component. If a CoSWID tag is for a patch, it MUST
contain the patch item and its value MUST be set to "true". If
not provided the default value MUST be considered "false".
o supplemental (label 11): A boolean value that indicates if the tag
is providing additional information to be associated with another
referenced SWID or CoSWID tag. Tags using this item help to
ensure that primary and patch tags provided by a software provider
are not modified by software management tools, while allowing
these tools to provide their own software metadata for a software
component. If a CoSWID tag is a supplemntal tag, it MUST contain
the supplemental item and its value MUST be set to "true". If not
provided the default value MUST be considered "false".
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o swid-name (label 1): This textual item provides the software
component name as it would typically be referenced. For example,
what would be seen in the add/remove software dialog in an
operating system, or what is specified as the name of a packaged
software component or a patch identifier name.
o software-version (label 13): A textual value representing the
specific underlying release or development version of the software
component.
o version-scheme (label 14): An 8-bit integer or textual value
representing the versioning scheme used for the software-version
item. If an integer value is used it MUST be a value from the
registry (see section Section 4.1 or a value in the private use
range: 32768-65,535.
o media (label 10): This text value is a hint to the tag consumer to
understand what this tag applies to. This item represents a query
as 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.
o software-meta-entry (label 5): An open-ended collection of key/
value data related to this CoSWID. A number of predefined
attributes can be used within this item providing for common usage
and semantics across the industry. The data definition of this
entry allows for any additional attribute to be included, though
it is recommended that industry norms for new attributes are
defined and followed to the degree possible. Described in
Section 2.6.
o entity-entry (label 2): Specifies the organizations related to the
software component referenced by this CoSWID tag. Described in
Section 2.4.
o link-entry (label 4): Provides a means to establish a relationship
arc between the tag and another item. A link can be used to
establish relationships between tags and to reference other
resources that are related to the CoSWID tag, e.g. vulnerability
database associations, ROLIE feeds, MUD files, software download
location, etc). This is modeled after the HTML "link" element.
Described in Section 2.5.
o payload-entry (label 6): 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 mechanisms in respect to that system entity - may
or may not include every item that could be created or executed on
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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). Described in
Section 2.7.3.
o evidence-entry (label 3): 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.
Described in Section 2.7.4.
o any-element-entry (label 7): A default map that can contain
arbitrary map members and even nested maps (which would also be
any-elements). In essence, the any-element allows items not
defined in this CDDL data definition to be included in a Concise
Software Identifier. Described in Section 2.3.
2.1.1. Determining the tag type
The operational model for SWID and CoSWID tags introduced in
Section 1.1. The following rules can be used to determine the type
of a CoSWID tag.
o Corpus Tag: A CoSWID tag MUST be considered a corpus tag if the
corpus item is "true".
o Primary Tag: A CoSWID tag MUST be considered a primary tag if the
corpus, patch, and supplemental items are "false".
o Patch Tag: A CoSWID tag MUST be considered a patch tag if the
patch item is "true" and the corpus item is "false".
o Supplemental Tag: A CoSWID tag MUST be considered a supplemental
tag if the supplemental item is set to "true".
A tag that does not match one of the above rules MUST be considered
an invalid, unsupported tag type.
If a patch modifies the version number or the descriptive metadata of
the software, then a new tag representing these details SHOULD be
installed, and the old tag SHOULD be removed.
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2.1.2. concise-software-identity Co-constraints
o Only one of the corpus, patch, and supplemental items MUST be set
to "true", or all of the corpus, patch, and supplemental items
MUST be set to "false" or be omitted.
o If the patch item is set to "true", the the tag SHOULD contain at
least one link with the rel(ation) item value of "patches" and an
href item specifying an association with the software that was
patched.
o If the supplemental item is set to "true", the the tag SHOULD
contain at least one link with the rel(ation) item value of
"supplements" and an href item specifying an association with the
software that is supplemented.
o If all of the corpus, patch, and supplemental items are "false",
or if the corpus item is set to "true", then a software-version
item MUST be included with a value set to the version of the
software component. This ensures that primary and corpus tags
have an identifiable software version.
2.2. The global-attributes Group
The global-attributes group provides 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 allowing for
additional items to be provided as a general point of extension in
the model.
The CDDL for the global-attributes is as follows:
global-attributes = (
? lang,
* any-attribute,
)
label = text / int
any-attribute = (
label => text / int / [ 2* text ] / [ 2* int ]
)
lang = (15: text)
The following describes each child item of this object.
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o lang (index 15): A language tag or corresponding IANA index
integer that conforms with IANA Language Subtag Registry
[RFC5646].
o any-attribute: This sub-group provides a means to include
arbitrary information via label (key) item value pairs where both
keys and values can be either a single integer or text string, or
an array of integers or text strings.
2.3. The any-element-map Entry
The CDDL for the any-element-entry object is as follows:
any-element-map = {
global-attributes,
* label => any-element-map / [ 2* any-element-map ],
}
any-element-entry = (7: any-element-map / [ 2* any-element-map ])
The following describes each child item of this object.
o global-attributes: The global-attributes group described in
Section 2.2.
o label: a single or multiple
2.4. The entity Object
The CDDL for the entity object is as follows:
entity = {
global-attributes,
entity-name,
? reg-id,
role,
? thumbprint,
extended-data,
}
any-uri = 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: hash-entry)
The following describes each child item of this object.
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o global-attributes: The global-attributes group described in
Section 2.2.
o entity-name (index 32): The text-string name of the organization
claiming a particular role in the CoSWID tag.
o reg-id (index 32): 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
scope of an organization. In a given scope, the registration id
MUST be used consistently.
o role (index 33): The relationship(s) 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
pre-defined roles include: "aggregator", "distributor",
"licensor", "software-creator", and "tag-creator". These pre-
defined role index and text values are defined in Section 3.2.
Use of index values instead of text for these pre-defined roles
allows a CoSWID to be more concise.
o thumbprint (index 34): The value of the thmbprint item provides an
integer-based hash algorithm identifier (hash-alg-id) and a byte
string string value (hash-value) that contains the corresponding
hash value (i.e. the thumbprint) of the signing entities
certificate(s). If the hash-alg-id is not known, then the integer
value "0" MUST be used. This ensures parity between the SWID tag
specification [SWID], which does not allow an algorithm to be
identified for this field. See Section 2.7.1 for more details on
the use of the hash-entry data structure.
o extended-data (index 30): An open-ended collection of elements
that can be used to attach arbitrary metadata to an entity item.
2.5. The link Object
The CDDL for the link object is as follows:
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link = {
global-attributes,
? artifact,
href,
? media
? ownership,
rel,
? media-type,
? use,
}
artifact = (37: text)
href = (38: any-uri)
media = (10: any-uri)
ownership = (39: "shared" / "private" / "abandon")
rel = (40: text)
media-type = (41: text)
use = (42: "optional" / "required" / "recommended")
The following describes each child item of this object.
o global-attributes: The global-attributes group described in
Section 2.2.
o artifact (index: 37): For installation media (rel="installation-
media"), this item value indicates the path of the installer
executable or script that can be run to launch the referenced
installation. Items with the same artifact name should be
considered mirrors of each other, allowing the installation media
to be downloaded from any of the described sources.
o href (index 38): The link to the item being referenced. The
"href" item's value can point to several different things, and can
be any of the following:
* If no URI scheme is provided, then the URI is to be interpreted
as being relative to the URI of the CoSWID tag. For example,
"./folder/supplemental.coswid".
* a physical resource location with any system-acceptable URI
scheme (e.g., file:// http:// https:// ftp://)
* a 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" references the tag with the tag-id
value "2df9de35-0aff-4a86-ace6-f7dddd1ade4c".
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* a 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 is "Contoso" or swidpath://SoftwareIdentity[Meta/@persist
entId='b0c55172-38e9-4e36-be86-92206ad8eddb'] would match
CoSWID tags with the persistent-id value
"b0c55172-38e9-4e36-be86-92206ad8eddb".
* See XPATH query standard : http://www.w3.org/TR/xpath20/
o media (index 10): See media defined in Section 2.1.
o ownership (index 39): Determines the relative strength of
ownership of the software components. Valid enumerations are:
abandon, private, shared
o rel (index 40): 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.
o media-type (index 41): 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.
o use (index 42): Determines if the target software is a hard
requirement or not. Valid enumerations are: required,
recommended, optional.
2.6. The software-meta Object
The CDDL for the software-meta object is as follows:
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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,
}
activation-status = (43: text)
channel-type = (44: text)
colloquial-version = (45: text)
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)
The following describes each child item of this object.
o global-attributes: The global-attributes group described in
Section 2.2.
o activation-status (index 43): Identification of the activation
status of this software title (e.g. Trial, Serialized, Licensed,
Unlicensed, etc). Typically, this is used in supplemental tags.
o channel-type (index 44): Provides information on which channel
this particular software was targeted for (e.g. Volume, Retail,
OEM, Academic, etc). Typically used in supplemental tags.
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o colloquial-version (index 45): 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 component 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).
o description (index 46): A longer, detailed description of the
software. This description can be multiple sentences
(differentiated from summary, which is a very short, one-sentence
description).
o edition (index 47): The variation of the product (Extended,
Enterprise, Professional, Standard etc).
o entitlement-data-required (index 48): An indicator to determine if
there should be accompanying proof of entitlement when a software
license reconciliation is completed.
o entitlement-key (index 49): A vendor-specific textual key that can
be used to reconcile the validity of an entitlement. (e.g. serial
number, product or license key).
o generator (index 50): 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.
o persistent-id (index 51): A GUID used to represent products
installed where the products are related, but may be different
versions.
o product (index 52): The base name of the product (e.g. ).
o product-family (index 53): 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
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of the backup system would have the same product-family name so
they can be grouped together in respect to reporting systems.
o revision (index 54): 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.
o summary (index 55): A short (one-sentence) description of the
software.
o unspsc-code (index 56): An 8 digit code that provides UNSPSC
classification of the software component this SWID tag identifies.
For more information see, http://www.unspsc.org/.
o unspsc-version (index 57): The version of the UNSPSC code used to
define the UNSPSC code value. For more information see,
http://www.unspsc.org/.
2.7. The Resource Collection Definition
2.7.1. The hash-entry Array
CoSWID add explicit support for the representation of hash entries
using algorithms that are registered at the Named Information Hash
Algorithm Registry via the hash-entry member (label 58).
hash-entry = (58: [ hash-alg-id: int, hash-value: bstr ] )
The number used as a value for hash-alg-id MUST refer an ID in the
Named Information Hash Algorithm Registry; other hash algorithms MUST
NOT be used. The hash-value MUST represent the raw hash value of the
hashed resource generated using the hash algorithm indicated by the
hash-alg-id.
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2.7.2. The 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.
The CDDL for the resource-collection group is as follows:
resource-collection = (
? directory-entry,
? file-entry,
? process-entry,
? resource-entry
)
directory = {
filesystem-item,
path-elements,
}
file = {
filesystem-item,
? size,
? file-version,
? hash-entry,
}
process = {
global-attributes,
process-name,
? pid,
}
resource = {
global-attributes,
type,
}
filesystem-item = (
global-attributes,
? key,
? location,
fs-name,
? root,
)
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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)
The following describes each child item or group for these groups.
o filesystem-item: 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: The global-attributes group described in
Section 2.2.
o directory-entry (index 16): A directory item allows one or more
directories to be defined in the file structure.
o file-entry (index 17): A file element that allows one or more
files to be specified for a given location.
o process-entry (index 18): Provides process (software component in
execution) information for data that will show up in a devices
process table.
o resource-entry (index 19): 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.
o size (index 20): The file size in bytes of the file.
o file-version (index 21): The version of the file.
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o key (index 22): 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.
o location (index 23): 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
from the location represented by the root item.
o fs-name (index 24): The file name or directory name without any
path characters.
o root (index 25): 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.
o path-elements (index 26): Provides the ability to apply a
directory structure to the path expressions for files defined in a
payload or evidence item.
o process-name (index 27): The process name as it will be found in
the system entity's process table.
o pid (index 28): The process ID for the process in execution that
can be included in the process item as part of an evidence tag.
o type (index 29): The type of resource represented via a text-
string (typically, registry-key, port or root-uri).
2.7.3. The payload Object
The CDDL for the payload object is as follows:
payload = {
global-attributes,
resource-collection,
* $$payload-extension
}
The following describes each child item of this object.
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o global-attributes: The global-attributes group described in
Section 2.2.
o resource-collection: The resource-collection group described in
Section 2.7.2.
o $$payload-extension: This CDDL socket (see [I-D.ietf-cbor-cddl]
section 3.9) can be used to extend the payload model, allowing
well-formed extensions to be defined in additional CDDL
descriptions.
2.7.4. The evidence Object
The CDDL for the evidence object is as follows:
evidence = {
global-attributes,
resource-collection,
? date,
? device-id,
* $$evidence-extension
}
date = (35: time)
device-id = (36: text)
The following describes each child item of this object.
o global-attributes: The global-attributes group described in
Section 2.2.
o resource-collection: The resource-collection group described in
Section 2.7.2.
o date (index 35): The date and time evidence represented by an
evidence item was gathered.
o device-id (index 36): A text-string identifier for a device
evidence was gathered from.
o $$evidence-extension: This CDDL socket (see [I-D.ietf-cbor-cddl]
section 3.9) can be used to extend the evidence model, allowing
well-formed extensions to be defined in additional CDDL
descriptions.
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2.8. Full CDDL Definition
In order to create a valid CoSWID document the structure of the
corresponding CBOR message MUST adhere to the following CDDL data
definition.
concise-software-identity = {
global-attributes,
tag-id,
tag-version,
? corpus,
? patch,
? supplemental,
swid-name,
? software-version,
? version-scheme,
? media,
? software-meta-entry,
entity-entry,
? link-entry,
? ( payload-entry // evidence-entry ),
* $$coswid-extension
}
any-uri = text
label = text / int
any-attribute = (
label => text / int / [ 2* text ] / [ 2* int ]
)
global-attributes = (
? lang,
* any-attribute,
)
resource-collection = (
? directory-entry,
? file-entry,
? process-entry,
? resource-entry
)
file = {
filesystem-item,
? size,
? file-version,
? hash-entry,
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}
filesystem-item = (
global-attributes,
? key,
? location,
fs-name,
? root,
)
directory = {
filesystem-item,
path-elements,
}
process = {
global-attributes,
process-name,
? pid,
}
resource = {
global-attributes,
type,
}
entity = {
global-attributes,
entity-name,
? reg-id,
role,
? thumbprint,
* $$entity-extension,
}
evidence = {
global-attributes,
resource-collection,
? date,
? device-id,
* $$evidence-extension
}
link = {
global-attributes,
? artifact,
href,
? media
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? ownership,
rel,
? media-type,
? use,
}
software-meta = {
global-attributes,
? activation-status,
? channel-type,
? colloquial-version,
? description,
? edition,
? entitlement-data-required,
? entitlement-key,
? generator,
? persistent-id,
? product,
? product-family,
? revision,
? summary,
? unspsc-code,
? unspsc-version,
}
payload = {
global-attributes,
resource-collection,
* $$payload-extension
}
tag-id = (0: text)
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)
corpus = (8: bool)
patch = (9: bool)
media = (10: [ + [ media-expression,
? [ media-operation,
media-expression,
]
]
])
media-operation = text
media-expression = media-environment / [ media-prefix,
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media-environment,
media-attribute,
media-value,
]
media-prefix = text
media-environment = text
media-attribute = text
media-value = text
supplemental = (11: bool)
tag-version = (12: integer)
software-version = (13: text)
version-scheme = (14: version-schemes / extended-value)
version-schemes = multipartnumeric / multipartnumeric-suffix / alphanumeric / decimal / semver
multipartnumeric = 1
multipartnumeric-suffix = 2
alphanumeric = 3
decimal = 4
semver = 16384
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)
entity-name = (31: text)
reg-id = (32: any-uri)
role = (33: roles / extended-value / [ 2* roles / extended-value ] )
extended-value = text / uint
roles= aggregator / distributor / licensor / software-creator / tag-creator
aggregator=0
distributor=1
licensor=2
software-creator=3
tag-creator=4
thumbprint = (34: [ hash-alg-id: int,
hash-value: bstr,
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]
)
date = (35: time)
device-id = (36: text)
artifact = (37: text)
href = (38: any-uri)
ownership = (39: shared / private / abandon / extended-value )
shared=0
private=1
abandon=2
rel = (40: rels / extended-value )
rels = ancestor / component / feature / installationmedia / packageinstaller / parent / patches / requires / see-also / supersedes / rel-supplemental
ancestor=0
component=1
feature=2
installationmedia=3
packageinstaller=4
parent=5
patches=6
requires=7
see-also=8
supersedes=9
rel-supplemental=10
media-type = (41: text)
use = (42: optional / required / recommended / extended-value )
optional=0
required=1
recommended=2
activation-status = (43: text)
channel-type = (44: text)
colloquial-version = (45: text)
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)
hash-entry = (58: [ hash-alg-id: int,
hash-value: bstr,
]
)
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3. CoSWID Indexed Label Values
3.1. Version Scheme
The following are an initial set of values for use in the version-
scheme item for the version schemes defined in the ISO/IEC
19770-2:2015 [SWID] specification. Index value in parens indicates
the index value to use in the version-scheme item.
o multipartnumeric (index 1): Numbers separated by dots, where the
numbers are interpreted as integers (e.g.,1.2.3, 1.4.5,
1.2.3.4.5.6.7)
o multipartnumeric+suffix (index 2): Numbers separated by dots,
where the numbers are interpreted as integers with an additional
string suffix(e.g., 1.2.3a)
o alphanumeric (index 3): Strictly a string, sorting is done
alphanumerically
o decimal (index 4): A floating point number (e.g., 1.25 is less
than 1.3)
o semver (index 16384): Follows the [SEMVER] specification
The values above are registered in the "SWID/CoSWID Version Schema
Values" registry defined in section Section 4.1. Additional valid
values will likely be registered over time in this registry.
3.2. Entity Role Values
The following table indicates the index value to use for the entity
roles defined in the ISO/IEC 19770-2:2015 [SWID] specification.
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+-------+-----------------+
| Index | Role Name |
+-------+-----------------+
| 0 | Reserved |
| | |
| 1 | tagCreator |
| | |
| 2 | softwareCreator |
| | |
| 3 | aggregator |
| | |
| 4 | distributor |
| | |
| 5 | licensor |
+-------+-----------------+
The values above are registered in the "SWID/CoSWID Entity Role
Values" registry defined in section Section 4.2. Additional valid
values will likely be registered over time. Additionally, the index
values 226 through 255 have been reserved for private use.
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.
This document has a number of IANA considerations, as described in
the following subsections.
4.1. SWID/CoSWID Version Schema Values Registry
This document uses unsigned 16-bit index values to version-scheme
item values. The initial set of version-scheme values are derived
from the textual version scheme names defined in the ISO/IEC
19770-2:2015 specification [SWID].
This document defines a new a new registry entitled "SWID/CoSWID
Version Schema Values". Future registrations for this registry are
to be made based on [RFC8126] as follows:
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+-------------+--------------------------+
| Range | Registration Procedures |
+-------------+--------------------------+
| 0-16383 | Standards Action |
| | |
| 16384-32767 | Specification Required |
| | |
| 32768-65535 | Reserved for Private Use |
+-------------+--------------------------+
Initial registrations for the SWID/CoSWID Version Schema Values
registry are provided below.
+-------------+--------------------------+-----------------+
| Index | Role Name | Specification |
+-------------+--------------------------+-----------------+
| 0 | Reserved | |
| | | |
| 1 | multipartnumeric | See Section 3.1 |
| | | |
| 2 | multipartnumeric+suffix | See Section 3.1 |
| | | |
| 3 | alphanumeric | See Section 3.1 |
| | | |
| 4 | decimal | See Section 3.1 |
| | | |
| 5-16383 | Unassigned | |
| | | |
| 16384 | semver | [SEMVER] |
| | | |
| 16385-32767 | Unassigned | |
| | | |
| 32768-65535 | Reserved for Private Use | |
+-------------+--------------------------+-----------------+
4.2. SWID/CoSWID Entity Role Values Registry
This document uses unsigned 8-bit index values to represent entity-
role values. The initial set of Entity roles are derived from the
textual role names defined in the ISO/IEC 19770-2:2015 specification
[SWID].
This document defines a new a new registry entitled "SWID/CoSWID
Entity Role Values". Future registrations for this registry are to
be made based on [RFC8126] as follows:
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+---------+--------------------------+
| Range | Registration Procedures |
+---------+--------------------------+
| 0-31 | Standards Action |
| | |
| 32-127 | Specification Required |
| | |
| 128-255 | Reserved for Private Use |
+---------+--------------------------+
Initial registrations for the SWID/CoSWID Entity Role Values registry
are provided below.
+---------+--------------------------+-----------------+
| Index | Role Name | Specification |
+---------+--------------------------+-----------------+
| 0 | Reserved | |
| | | |
| 1 | tagCreator | See Section 3.2 |
| | | |
| 2 | softwareCreator | See Section 3.2 |
| | | |
| 3 | aggregator | See Section 3.2 |
| | | |
| 4 | distributor | See Section 3.2 |
| | | |
| 5 | licensor | See Section 3.2 |
| | | |
| 6-49 | Unassigned | |
| | | |
| 50-225 | Unassigned | |
| | | |
| 225-255 | Reserved for Private Use | |
+---------+--------------------------+-----------------+
4.3. Media Type Registration
4.3.1. swid+cbor Media Type Registration
Type name: application
Subtype name: swid+cbor
Required parameters: none
Optional parameters: none
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Encoding considerations: Must be encoded as using [RFC7049]. See
RFC-AAAA for details.
Security considerations: See Section 5 of RFC-AAAA.
Interoperability considerations: Applications MAY ignore any key
value pairs that they do not understand. This allows backwards
compatible extensions to this specification.
Published specification: RFC-AAAA
Applications that use this media type: The type is used by Software
asset management systems, Vulnerability assessment systems, and in
applications that use remote integrity verification.
Fragment identifier considerations: Fragment identification for
application/swid+cbor is supported by using fragment identifiers as
specified by RFC-AAAA. [Section to be defined]
Additional information:
Magic number(s): first five bytes in hex: da 53 57 49 44
File extension(s): coswid
Macintosh file type code(s): none
Macintosh Universal Type Identifier code: org.ietf.coswid conforms to
public.data
Person & email address to contact for further information: Henk
Birkholz <henk.birkholz@sit.fraunhofer.de>
Intended usage: COMMON
Restrictions on usage: None
Author: Henk Birkholz <henk.birkholz@sit.fraunhofer.de>
Change controller: IESG
4.4. CoAP Content-Format Registration
IANA is requested to assign a CoAP Content-Format ID for the CoSWID
media type in the "CoAP Content-Formats" sub-registry, from the "IETF
Review or IESG Approval" space (256..999), within the "CoRE
Parameters" registry [RFC7252]:
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+-----------------------+----------+-------+-----------+
| Media type | Encoding | ID | Reference |
+-----------------------+----------+-------+-----------+
| application/swid+cbor | - | TBDcf | RFC-AAAA |
+-----------------------+----------+-------+-----------+
Table 1: CoAP Content-Format IDs
4.5. CBOR Tag Registration
IANA is requested to allocate a tag in the CBOR Tags Registry,
preferably with the specific value requested:
+------------+----------+-------------------------------------------+
| Tag | Data | Semantics |
| | Item | |
+------------+----------+-------------------------------------------+
| 1398229316 | map | Concise Software Identifier (CoSWID) |
| | | [RFC-AAAA] |
+------------+----------+-------------------------------------------+
5. Security Considerations
SWID and CoSWID tags contain public information about software
components 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 has been validated can be relied
upon to be unchanged since it was signed. If the SWID tag was
created by the software provider, is signed, and the software
provider can be authenticated as the originator of the signature,
then the tag can be considered authoritative. In this way, an
authoritative SWID tag contains information about a software product
provided by the maintainer of the product, who is expected to be an
expert in their own product. Thus, authoritative SWID tags can be
trusted to represent authoritative information about the software
product. Having an authoritative SWID tag can be useful when the
information in the tag needs to be trusted, such as when the tag is
being used to convey reference integrity measurements for software
components. By contrast, the data contained in unsigned tags cannot
be trusted to be unmodified.
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SWID tags are designed to be easily added and removed from an
endpoint along with the installation or removal of software
components. On endpoints where addition or removal of software
components 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 components. 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 intent
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
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.
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6. Acknowledgments
7. Change Log
Changes from version 06 to version 07:
o Added version-scheme definitions
o Added stubs for additional extension points
o Added value registry request
o Added media type registration request
o Added content format registration request
o Added CBOR tag registration request
o Fixed any-element-map
o Removed RIM appedix to be addressed in complementary draft
o Removed CWT appendix
o Flagged firmware resource colletion appendix for revision
Changes from version 05 to version 06:
o Improved quantities
o Included proposals for implicet enumerations that were NMTOKENS
o Added extension points
o Improved exemplary firmware-resource extension
Changes from version 04 to version 05:
o Clarified language around SWID and CoSWID to make more consistant
use of these terms.
o Added language describing CBOR optimizations for single vs. arrays
in the model front matter.
o Fixed a number of gramatical, spelling, and wording issues.
o Documented extension points that use CDDL sockets.
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o Converted IANA registration tables to markdown tables, reserving
the 0 value for use when a value is not known.
o Updated a number of references to their current versions.
Changes from version 03 to version 04:
o Re-index label values in the CDDL.
o Added a section describing the CoSWID model in detail.
o Created IANA registries for entity-role and version-scheme
Changes from version 02 to version 03:
o Updated CDDL to allow for a choice between a payload or evidence
o Re-index label values in the CDDL.
o Added item definitions
o Updated references for COSE, CBOR Web Token, and CDDL.
Changes from version 01 to version 02:
o Added extensions for Firmware and CoSWID use as Reference
Integrity Measurements (CoSWID RIM)
o Changes meta handling in CDDL from use of an explicit use of items
to a more flexible unconstrained collection of items.
o Added sections discussing use of COSE Signatures and CBOR Web
Tokens
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
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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
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
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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-15
(work in progress), March 2018.
[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>.
[RFC5646] Phillips, A., Ed. and M. Davis, Ed., "Tags for Identifying
Languages", BCP 47, RFC 5646, DOI 10.17487/RFC5646,
September 2009, <https://www.rfc-editor.org/info/rfc5646>.
[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>.
[RFC7252] Shelby, Z., Hartke, K., and C. Bormann, "The Constrained
Application Protocol (CoAP)", RFC 7252,
DOI 10.17487/RFC7252, June 2014,
<https://www.rfc-editor.org/info/rfc7252>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
[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.
[SEMVER] Preston-Werner, T., "Semantic Versioning 2.0.0", n.d.,
<https://semver.org/spec/v2.0.0.html>.
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[SWID] "Information technology - Software asset management - Part
2: Software identification tag", ISO/IEC 19770-2:2015,
October 2015.
[SWID-GUIDANCE]
Waltermire, D., Cheikes, B., Feldman, L., and G. Witte,
"Guidelines for the Creation of Interoperable Software
Identification (SWID) Tags", NISTIR 8060, April 2016,
<https://doi.org/10.6028/NIST.IR.8060>.
[X.1520] "Recommendation ITU-T X.1520 (2014), Common
vulnerabilities and exposures", April 2011.
9.2. Informative References
[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 and JSON data structures", draft-ietf-cbor-
cddl-05 (work in progress), August 2018.
[I-D.ietf-sacm-rolie-softwaredescriptor]
Banghart, S. and D. Waltermire, "Definition of the ROLIE
Software Descriptor Extension", draft-ietf-sacm-rolie-
softwaredescriptor-03 (work in progress), July 2018.
[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-15 (work in progress), June 2018.
[RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally
Unique IDentifier (UUID) URN Namespace", RFC 4122,
DOI 10.17487/RFC4122, July 2005,
<https://www.rfc-editor.org/info/rfc4122>.
[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>.
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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>.
Appendix A. CoSWID Attributes for Firmware (label 60)
NOTE: this appendix is subject to revision based potential
convergence of:
o draft-moran-suit-manifest, and
o draft-birkholz-suit-coswid-manifest
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
points "$$payload-extension" and "$$evidence-extension" are 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 extension points "$$payload-
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extension" and "$$evidence-extension" in respect to firmware MUST
adhere to the following CDDL data definition.
<CODE BEGINS>
$$payload-extension //= (suit.manifest-entry,)
$$evidence-extension //= (suit.manifest-entry,)
suit-manifest = {
suit.manifest-version,
suit.digest-info,
suit.text-reference,
suit.nonce,
suit.sequence-number,
? suit.pre-condition,
? suit.post-condition,
? suit.directives,
? suit.resources,
? suit.processors,
? suit.targets,
? suit.extensions,
}
suit.manifest-entry = (59: suit-manifest / [ 2* suit-manifest ] )
suit.manifest-version = (60: 1)
suit.digest-info = (61: [ suit.digest-algorithm,
? suit.digest-parameters,
]
)
suit.digest-algorithm = uint
suit.digest-parameters = bytes
suit.text-reference = (62: bytes)
suit.nonce = (63: bytes)
suit.sequence-number = (64: uint)
suit.pre-condition = (suit.id-condition // suit.time-condition // suit.image-condition // suit.custom-condition)
suit.post-condition = (suit.image-condition // suit.custom-condition)
suit.id-condition = (65: [ + [ suit.vendor / suit.class / suit.device,
suit.uuid,
]
]
)
suit.vendor = 0
suit.class = 1
suit.device = 2
suit.uuid = bstr .size 16
suit.time-condition = (66: [ + [ suit.install-after / suit.best-before,
suit.timestamp,
]
]
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)
suit.install-after = 0
suit.best-before = 1
suit.timestamp = uint .size 8
suit.image-condition = (67: [ + [ suit.current-content / suit.not-current-content,
suit.storage-identifier,
? suit.digest,
]
]
)
suit.current-content = 0
suit.not-current-content = 1
suit.digest = bytes
suit.storage-identifier = bytes
suit.custom-condition = (68: [ nint,
suit.condition-parameters,
]
)
suit.condition-parameters = bytes
suit.directives = (69: { + int => bytes } )
suit.resources = (70: [ + [ suit.resource-type,
suit.uri-list,
suit.digest,
suit.onode,
? suit.size,
]
]
)
suit.resource-type = suit.payload / suit.dependency / suit.key / suit.alias
suit.payload = 0
suit.dependency = 1
suit.key = 2
suit.alias = 3
suit.uri-list = { + int => text }
suit.size = uint
suit.onode = bytes
suit.processors = (71: [ + [ suit.decrypt / suit.decompress / suit.undiff / suit.relocate / suit.unrelocate,
suit.parameters,
suit.inode,
suit.onode,
]
]
)
suit.decrypt = 0
suit.decompress = 1
suit.undiff = 2
suit.relocate = 3
suit.unrelocate = 4
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suit.parameters = bytes
suit.inode = bytes
suit.targets = (72: [ + [ suit.component-id,
suit.storage-identifier,
suit.inode,
? suit.encoding,
]
]
)
suit.component-id = [ + bytes ]
suit.encoding = bytes
suit.extensions = (73: { + int => bytes } )
<CODE ENDS>
The members of the firmware group that constitutes the content of the
firmware-entry is based on the metadata about firmware Described 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.
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 B. 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 component 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 measurements 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
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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.
<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>
Authors' Addresses
Henk Birkholz
Fraunhofer SIT
Rheinstrasse 75
Darmstadt 64295
Germany
Email: henk.birkholz@sit.fraunhofer.de
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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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