Internet-Draft CoSWID May 2020
Birkholz, et al. Expires 2 November 2020 [Page]
Workgroup:
SACM Working Group
Internet-Draft:
draft-ietf-sacm-coswid-15
Published:
Intended Status:
Standards Track
Expires:
Authors:
H. Birkholz
Fraunhofer SIT
J. Fitzgerald-McKay
Department of Defense
C. Schmidt
The MITRE Corporation
D. Waltermire
NIST

Concise Software Identification Tags

Abstract

ISO/IEC 19770-2:2015 Software Identification (SWID) tags provide an extensible XML-based structure to identify and describe individual software components, patches, and installation bundles. SWID tag representations can be too large for devices with network and storage constraints. This document defines a concise representation of SWID tags: Concise SWID (CoSWID) tags. CoSWID supports the same features as SWID tags, as well as additional semantics that allow CoSWIDs to describe additional types of information, all in a more memory efficient format.

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 2 November 2020.

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Table of Contents

1. Introduction

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 software, a patch, or an installation bundle, which are referred to as software components in this document. 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.

SWID tags are used to support a number of processes including but not limited to:

While there are very few required fields in SWID tags, there are many optional fields that support different uses. A SWID tag consisting of only required fields might be a few hundred bytes in size; however, 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 usage scenarios, 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 the Concise Binary Object Representation (CBOR) [RFC7049], which maps the human-readable labels of SWID data items 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.

1.1. The SWID and CoSWID 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 software component's SWID tag is also installed. Likewise, when the software component 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 corresponding SWID tags for these components on that endpoint. CoSWIDs share the same lifecycle requirements as a SWID tag.

The SWID specification and supporting guidance provided in NIST Internal Report (NISTIR) 8060: Guidelines for the Creation of Interoperable SWID Tags [SWID-GUIDANCE] defines four types of SWID tags: primary, patch, corpus, and supplemental. The following text is paraphrased from these sources.

  1. Primary Tag - A SWID or CoSWID tag that identifies and describes an installed software component on an endpoint. A primary tag is intended to be installed on an endpoint along with the corresponding software component.
  2. Patch Tag - A SWID or CoSWID tag that identifies and describes an installed patch that has made incremental changes to a software component installed on an endpoint. A patch tag is intended to be installed on an endpoint along with the corresponding software component patch.
  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 allows tools and users to record their own metadata about a software component without modifying SWID primary or patch tags created by a software provider.

The type of a tag is determined by specific data elements, which are discussed in Section 3.

  • Corpus, primary, and patch tags have similar functions in that they describe the existence and/or presence of different types of software components (e.g., software installers, software installations, software patches), and, potentially, different states of these software components. Supplemental tags have the same structure as other tags, but are used to provide information not contained in the referenced corpus, primary, and patch tags. All 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            |
Software      Software        Software     Software      Software
Deployment -> Installation -> Patching  -> Upgrading  -> Removal

Corpus        Primary         Primary      xPrimary      xPrimary
Supplemental  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. The figure identifies the types of tags that can be deployed and previously deployed tags that are typically removed (indicated by an "x" prefix) at each lifecycle stage, 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 can also be installed during software installation to provide information about software fixes deployed along with the base software installation.
    • Software Patching. A new patch tag is provided, when a patch is applied to the software component, 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.
    • 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.

As 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.

Understanding the use of CoSWIDs in the software lifecycle provides a basis for understanding the information provided in a CoSWID and the associated semantics of this information. 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 Format

This document defines the CoSWID tag format, which is based on CBOR. CBOR-based CoSWID tags offer a more concise representation of SWID information as compared to the XML-based SWID tag representation in ISO-19770-2:2015. The structure of a CoSWID is described via the Concise Data Definition Language (CDDL) [RFC8610]. The resulting CoSWID data definition is aligned to the information able to be expressed with the XML schema definition of ISO-19770-2:2015 [SWID]. This alignment allows both SWID and CoSWID tags to represent a common set of software component information and allows CoSWID tags to support the same uses as a SWID tag. To achieve this end, the CDDL representation includes every SWID tag field and attribute.

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 (indices). The names used in the CDDL data definition and the mapping to the CBOR representation using integer indices is based on the vocabulary of the XML attribute and element names defined in ISO/IEC 19770-2:2015.

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 BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.

2. Concise SWID Data Definition

The following describes the general rules and processes for encoding data using CDDL representation. Prior familiarity with CBOR and CDDL concepts will be helpful in understanding this CoSWID data definition.

This section describes the rules by which SWID tag XML is represented in the CoSWID CDDL structure. The CamelCase [CamelCase] notation used in the XML schema definition is changed to a hyphen-separated notation [KebabCase] (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 to by its name in CamelCase notation explicitly relates to XML SWID tags; an attribute referred to by its name in KebabCase notation explicitly relates to CBOR CoSWID tags. This approach simplifies the composition of further work that reference both XML SWID and CBOR CoSWID documents.

In most cases, mapping attribute names between SWID and CoSWID can be done automatically by converting between CamelCase and KebabCase attribute names. However, some CoSWID CDDL attribute names show greater variation relative to their corresponding SWID XML Schema attributes. This is done when the change improves clarity in the specification. For example the "name" and "version" SWID fields corresponds to the "software-name" and "software-version" CoSWID fields, respectively. As such, it is not always possible to mechanically translate between corresponding attribute names in the two formats. In such cases, a manual mapping will need to be used.

The 57 human-readable text labels of the CDDL-based CoSWID vocabulary are mapped to integer indices via a block of rules at the bottom of the definition. This allows a more concise integer-based form to be stored or transported, as compared to the less efficient text-based form of the original vocabulary.

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 rule above allows either a single data item or an array of 2 or more data values to be provided. When a singleton data value is provided, the CBOR markers for the array, array length, and stop point are not needed, saving bytes. When two or more data values are provided, these values are encoded as an array. This modeling pattern is used frequently in the CoSWID CDDL data definition to allow for more efficient encoding of singleton values.

The following subsections describe the different parts of the CoSWID model.

2.1. Character Encoding

The CDDL "text" type is represented in CBOR as a major type 3, which represents "a string of Unicode characters that [are] encoded as UTF-8 [RFC3629]" (see [RFC7049] section 2.1). Thus both SWID and CoSWID use UTF-8 for the encoding of characters in text strings.

To ensure that UTF-8 character strings are able to be encoded/decoded and exchanged interoperably, text strings in CoSWID MUST be encoded consistent with the Net-Unicode definition defined in [RFC5198].

All names registered with IANA according to requirements in section Section 5.2 also need to be valid according to the XML Schema NMToken data type (see [W3C.REC-xmlschema-2-20041028] section 3.3.4) to ensure compatibility with the SWID specification where these names are used.

2.2. Concise SWID Extensions

The CoSWID data definition contains two features that are not included in the SWID data definition on which it is based. These features are:

  • The explicit definition of types for some attributes in the ISO-19770-2:2015 XML representation that are typically represented by the "any attribute" in the SWID model. These are covered in Section 2.5.
  • The inclusion of extension points in the CoSWID data definition using CDDL sockets (see [RFC8610] section 3.9). The use of CDDL sockets allow for well-formed extensions to be defined in supplementary CDDL descriptions that support additional uses of CoSWID tags that go beyond the original scope of ISO-19770-2:2015 tags. This extension mechanism can also be used to update the CoSWID format as revisions to ISO-19770-2 are published.

The following CDDL sockets (extension points) are defined in this document, which allow the addition of new information structures to their respective CDDL groups.

Table 1: CoSWID CDDL Group Extension Points
Map Name CDDL Socket Defined in
concise-swid-tag $$coswid-extension Section 2.3
entity-entry $$entity-extension Section 2.6
link-entry $$link-extension Section 2.7
software-meta-entry $$software-meta-extension Section 2.8
file-entry $$file-extension Section 2.9.2
directory-entry $$directory-extension Section 2.9.2
process-entry $$process-extension Section 2.9.2
resource-entry $$resource-extension Section 2.9.2
payload-entry $$payload-extension Section 2.9.3
evidence-entry $$evidence-extension Section 2.9.4

The CoSWID Items Registry defined in Section 5.1 provides a registration mechanism allowing new items, and their associated index values, to be added to the CoSWID model through the use of the CDDL sockets described in the table above. This registration mechanism provides for well-known index values for data items in CoSWID extensions, allowing these index values to be recognized by implementations supporting a given extension.

The following additional CDDL sockets are defined in this document to allow for adding new values to corresponding type-choices (i.e. to represent enumerations) via custom CDDL data definitions.

Table 2: CoSWID CDDL Enumeration Extension Points
Enumeration Name CDDL Socket Defined in
version-scheme $version-scheme Section 4.1
role $role Section 4.2
ownership $ownership Section 4.3
rel $rel Section 4.4
use $use Section 4.5

A number of SWID/CoSWID value registries are also defined in Section 5.2 that allow new values to be registered with IANA for the enumerations above. This registration mechanism supports the definition of new well-known index values and names for new enumeration values used by both SWID and CoSWID. This registration mechanism allows new standardized enumerated values to be shared between both specifications (and implementations) over time, and references to the IANA registries will be added to the next revision of [SWID].

2.3. The concise-swid-tag Map

The CDDL data definition for the root concise-swid-tag map is as follows and this rule and its constraints MUST be followed when creating or validating a CoSWID tag:

concise-swid-tag = {
  global-attributes,
  tag-id => text / bstr .size 16,
  tag-version => integer,
  ? corpus => bool,
  ? patch => bool,
  ? supplemental => bool,
  software-name => text,
  ? software-version => text,
  ? version-scheme => $version-scheme,
  ? media => text,
  ? software-meta =>  software-meta-entry / [ 2* software-meta-entry ],
  entity => entity-entry / [ 2* entity-entry ],
  ? link => link-entry / [ 2* link-entry ],
  ? (( payload => payload-entry ) // ( evidence => evidence-entry )),
  * $$coswid-extension,
}

tag-id = 0
software-name = 1
entity = 2
evidence = 3
link = 4
software-meta = 5
payload = 6
corpus = 8
patch = 9
media = 10
supplemental = 11
tag-version = 12
software-version = 13
version-scheme = 14

$version-scheme /= multipartnumeric
$version-scheme /= multipartnumeric-suffix
$version-scheme /= alphanumeric
$version-scheme /= decimal
$version-scheme /= semver
$version-scheme /= uint / text
multipartnumeric = 1
multipartnumeric-suffix = 2
alphanumeric = 3
decimal = 4
semver = 16384

The following describes each member of the concise-swid-tag root map.

  • 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 2.5.
  • tag-id (index 0): A 16 byte binary string or textual identifier uniquely referencing a software component. The tag identifier MUST be globally unique. If represented as a 16 byte binary string, the identifier MUST be a valid universally unique identifier as defined by [RFC4122]. There are no strict guidelines on how this identifier is structured, but examples include a 16 byte GUID (e.g. class 4 UUID) [RFC4122], or a text string appended to a DNS domain name to ensure uniqueness across organizations.
  • tag-version (index 12): An integer value that indicate the specific release revision of the tag. 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 value allows a CoSWID tag producer to correct an incorrect tag previously released without indicating a change to the underlying software component the tag represents. For example, the tag version could be changed to add new metadata, to correct a broken link, to add a missing payload entry, etc. When producing a revised tag, the new tag-version value MUST be greater than the old tag-version value.
  • corpus (index 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".

  • patch (index 9): A boolean value that indicates if the tag identifies and describes an installed patch that has made incremental changes to a software component installed on an endpoint. 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, the patch item MUST be set to "true". If not provided, the default value MUST be considered "false".

    Note: If the software component's version number is modified, then the correct course of action would be to replace the previous primary tag for the component with a new primary tag that reflected this new version. In such a case, the new tag would have a patch item value of "false" or would omit this item completely.

  • supplemental (index 11): A boolean value that indicates if the tag is providing additional information to be associated with another referenced SWID or CoSWID tag. This allows tools and users to record their own metadata about a software component without modifying SWID primary or patch tags created by a software provider. If a CoSWID tag is a supplemental tag, the supplemental item MUST be set to "true". If not provided, the default value MUST be considered "false".
  • software-name (index 1): This textual item provides the software component's name. This name is likely the same name that would appear in a package management tool.
  • software-version (index 13): A textual value representing the specific release or development version of the software component.
  • version-scheme (index 14): An integer or textual value representing the versioning scheme used for the software-version item. If an integer value is used it MUST be an index value in the range -256 to 65535. Integer values in the range -256 to -1 are reserved for testing and use in closed environments (see section Section 5.2.2). Integer values in the range 0 to 65535 correspond to registered entries in the IANA "SWID/CoSWID Version Scheme Value" registry (see section Section 5.2.4. If a string value is used it MUST be a private use name as defined in section Section 5.2.2. String values based on a Version Scheme Name from the IANA "SWID/CoSWID Version Scheme Value" registry MUST NOT be used, as these values are less concise than their index value equivalent.
  • media (index 10): This text value is a hint to the tag consumer to understand what target platform this tag applies to. This item represents a query as defined by the W3C Media Queries Recommendation (see [W3C.REC-css3-mediaqueries-20120619]).
  • software-meta (index 5): An open-ended map of key/value data pairs. A number of predefined keys can be used within this item providing for common usage and semantics across the industry. Use of this map allows any additional attribute to be included in the tag. It is expected that industry groups will use a common set of attribute names to allow for interoperability within their communities. Described in Section 2.8.
  • entity (index 2): Provides information about one or more organizations responsible for producing the CoSWID tag, and producing or releasing the software component referenced by this CoSWID tag. Described in Section 2.6.
  • link (index 4): Provides a means to establish relationship arcs between the tag and another items. A given link can be used to establish the relationship between tags or to reference another resource that is related to the CoSWID tag, e.g. vulnerability database association, ROLIE feed [RFC8322], MUD resource [RFC8520], software download location, etc). This is modeled after the HTML "link" element. Described in Section 2.7.
  • payload (index 6): This item represents a collection of software artifacts (described by child items) that compose the target software. For example, these artifacts could be the files included with an installer for a corpus tag or installed on an endpoint when the software component is installed for a primary or patch tag. The artifacts listed in a payload may be a superset of the software artifacts that are actually installed. Based on user selections at install time, an installation might not include every artifact that could be created or executed on the endpoint when the software component is installed or run. Described in Section 2.9.3.
  • evidence-entry (index 3): This item can be used to record the results of a software discovery process used to identify untagged software on an endpoint or to represent indicators for why software is believed to be installed on the endpoint. In either case, a CoSWID tag can be created by the tool performing an analysis of the software components installed on the endpoint. Described in Section 2.9.4.
  • $$coswid-extension: This CDDL socket is used to add new information structures to the concise-swid-tag root map. See Section 2.2.

2.4. concise-swid-tag Co-constraints

The following co-constraints apply to the information provided in the concise-swid-tag group.

  • The patch and supplemental items MUST NOT both be set to "true".
  • If the patch item is set to "true", the tag SHOULD contain at least one link item (see section Section 2.7) with both the rel item value of "patches" and an href item specifying an association with the software that was patched.
  • If the supplemental item is set to "true", the tag SHOULD contain at least one link item with both the rel item value of "supplemental" and an href item specifying an association with the software that is supplemented.
  • 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.

2.5. 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 follows:

global-attributes = (
  ? lang,
  * any-attribute,
)

any-attribute = (
  label => text / int / [ 2* text ] / [ 2* int ]
)

label = text / int

The following describes each child item of this group.

  • lang (index 15): A textual language tag that conforms with IANA "Language Subtag Registry" [RFC5646]. The context of the specified language applies to all sibling and descendant textual values, unless a descendant object has defined a different language tag. Thus, a new context is established when a descendant object redefines a new language tag. All textual values within a given context MUST be considered expressed in the specified language.
  • any-attribute: This sub-group provides a means to include arbitrary information via label/index ("key") value pairs. Labels can be either a single integer or text string. Values can be a single integer, a text string, or an array of integers or text strings.

2.6. The entity-entry Map

The CDDL for the entity-entry map follows:

entity-entry = {
  global-attributes,
  entity-name => text,
  ? reg-id => any-uri,
  role => $role / [ 2* $role ],
  ? thumbprint => hash-entry,
  * $$entity-extension,
}

entity-name = 31
reg-id = 32
role = 33
thumbprint = 34

$role /= tag-creator
$role /= software-creator
$role /= aggregator
$role /= distributor
$role /= licensor
$role /= maintainer
$role /= uint / text
tag-creator=1
software-creator=2
aggregator=3
distributor=4
licensor=5
maintainer=6

The following describes each child item of this group.

  • global-attributes: The global-attributes group described in Section 2.5.
  • entity-name (index 32): The textual name of the organizational entity claiming the roles specified by the role item for the CoSWID tag.
  • reg-id (index 32): The registration id value is intended to uniquely identify a naming authority in a given scope (e.g. global, organization, vendor, customer, administrative domain, etc.) for the referenced entity. 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 for CoSWID tag production.

  • role (index 33): An integer or textual value representing the relationship(s) between the entity, and this tag or the referenced software component. If an integer value is used it MUST be an index value in the range -256 to 255. Integer values in the range -256 to -1 are reserved for testing and use in closed environments (see section Section 5.2.2). Integer values in the range 0 to 255 correspond to registered entries in the IANA "SWID/CoSWID Entity Role Value" registry (see section Section 5.2.5. If a string value is used it MUST be a private use name as defined in section Section 5.2.2. String values based on a Role Name from the IANA "SWID/CoSWID Entity Role Value" registry MUST NOT be used, as these values are less concise than their index value equivalent.

    The following additional requirements exist for the use of the "role" item:

    • An entity item MUST be provided with the role of "tag-creator" for every CoSWID tag. This indicates the organization that created the CoSWID tag.
    • An entity item SHOULD be provided with the role of "software-creator" for every CoSWID tag, if this information is known to the tag creator. This indicates the organization that created the referenced software component.
  • thumbprint (index 34): The value of the thumbprint item provides an integer-based hash algorithm identifier (hash-alg-id) and a byte string value (hash-value) that contains the corresponding hash value (i.e. the thumbprint) of the signing entity's public key certificate. This provides an indicator of which entity signed the CoSWID tag, which will typically be the tag creator. 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 2.9.1 for more details on the use of the hash-entry data structure.
  • $$entity-extension: This CDDL socket can be used to extend the entity-entry group model. See Section 2.2.

2.8. The software-meta-entry Map

The CDDL for the software-meta-entry map follows:

software-meta-entry = {
  global-attributes,
  ? activation-status => text,
  ? channel-type => text,
  ? colloquial-version => text,
  ? description => text,
  ? edition => text,
  ? entitlement-data-required => bool,
  ? entitlement-key => text,
  ? generator => text,
  ? persistent-id => text,
  ? product => text,
  ? product-family => text,
  ? revision => text,
  ? summary => text,
  ? unspsc-code => text,
  ? unspsc-version => text,
  * $$software-meta-extension,
}

activation-status = 43
channel-type = 44
colloquial-version = 45
description = 46
edition = 47
entitlement-data-required = 48
entitlement-key = 49
generator = 50
persistent-id = 51
product = 52
product-family = 53
revision = 54
summary = 55
unspsc-code = 56
unspsc-version = 57

The following describes each child item of this group.

  • global-attributes: The global-attributes group described in Section 2.5.
  • activation-status (index 43): A textual value that identifies how the software component has been activated, which might relate to specific terms and conditions for its use (e.g. Trial, Serialized, Licensed, Unlicensed, etc) and relate to an entitlement. This attribute is typically used in supplemental tags as it contains information that might be selected during a specific install.
  • channel-type (index 44): A textual value that identfies which sales, licensing, or marketing channel the software component has been targeted for (e.g. Volume, Retail, OEM, Academic, etc). This attribute is typically used in supplemental tags as it contains information that might be selected during a specific install.
  • colloquial-version (index 45): A textual value for the software component's informal or colloquial version. Examples may include a year value, a major version number, or similar value that are used to identify a group of specific software component releases that are part of the same release/support cycle. This version can be the same through multiple releases of a software component, while the software-version specified in the concise-swid-tag group is much more specific and will change for each software component release. This version is intended to be used for string comparison only and is not intended to be used to determine if a specific value is earlier or later in a sequence.
  • description (index 46): A textual value that provides a detailed description of the software component. This value MAY be multiple paragraphs separated by CR LF characters as described by [RFC5198].
  • edition (index 47): A textual value indicating that the software component represents a functional variation of the code base used to support multiple software components. For example, this item can be used to differentiate enterprise, standard, or professional variants of a software component.
  • entitlement-data-required (index 48): A boolean value that can be used to determine if accompanying proof of entitlement is needed when a software license reconciliation process is performed.
  • entitlement-key (index 49): A vendor-specific textual key that can be used to identify and establish a relationship to an entitlement. Examples of an entitlement-key might include a serial number, product key, or license key. For values that relate to a given software component install (i.e., license key), a supplemental tag will typically contain this information. In other cases, where a general-purpose key can be provided that applies to all possible installs of the software component on different endpoints, a primary tag will typically contain this information.
  • generator (index 50): The name (or tag-id) of the software component that created the CoSWID tag. If the generating software component has a SWID or CoSWID tag, then the tag-id for the generating software component SHOULD be provided.
  • persistent-id (index 51): A globally unique identifier used to identify a set of software components that are related. Software components sharing the same persistent-id can be different versions. This item can be used to relate software components, released at different points in time or through different release channels, that may not be able to be related through use of the link item.
  • product (index 52): A basic name for the software component that can be common across multiple tagged software components (e.g., Apache HTTPD).
  • product-family (index 53): A textual value indicating the software components overall product family. This should be used when multiple related software components form a larger capability that is installed on multiple different endpoints. For example, some software families may consist of server, client, and shared service components that are part of a larger capability. Email systems, enterprise applications, backup services, web conferencing, and similar capabilities are examples of families. Use of this item is not intended to represent groups of software that are bundled or installed together. The persistent-id or link items SHOULD be used to relate bundled software components.
  • revision (index 54): A string value indicating an informal or colloquial release version of the software. This value can provide a different version value as compared to the software-version specified in the concise-swid-tag group. This is useful when one or more releases need to have an informal version label that differs from the specific exact version value specified by software-version. Examples can include SP1, RC1, Beta, etc.
  • summary (index 55): A short description of the software component. This MUST be a single sentence suitable for display in a user interface.
  • unspsc-code (index 56): An 8 digit UNSPSC classification code for the software component. For more information see https://www.unspsc.org/.
  • unspsc-version (index 57): The version of UNSPSC used to define the unspsc-code value.
  • $$meta-extension: This CDDL socket can be used to extend the software-meta-entry group model. See Section 2.2.

2.9. The Resource Collection Definition

2.9.1. The hash-entry Array

CoSWID adds explicit support for the representation of hash entries using algorithms that are registered in the IANA "Named Information Hash Algorithm Registry" using the hash member (index 7) and the corresponding hash-entry type.

hash-entry = [
  hash-alg-id: int,
  hash-value: bytes,
]

The number used as a value for hash-alg-id MUST refer an ID in the "Named Information Hash Algorithm Registry" (see https://www.iana.org/assignments/named-information/named-information.xhtml); 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.

2.9.2. The resource-collection Group

A list of items both used in evidence (created by a software discovery process) and payload (installed in an endpoint) content of a CoSWID tag document to structure and differentiate the content of specific CoSWID tag types. Potential content includes directories, files, processes, or resources.

The CDDL for the resource-collection group follows:

path-elements-group = ( ? directory => directory-entry / [ 2* directory-entry ],
                        ? file => file-entry / [ 2* file-entry ],
                      )

esource-collection = (
  path-elements-group,
  ? process => process-entry / [ 2* process-entry ],
  ? resource => resource-entry / [ 2* resource-entry ],
  * $$resource-collection-extension,
)

filesystem-item = (
  global-attributes,
  ? key => bool,
  ? location => text,
  fs-name => text,
  ? root => text,
)

file-entry = {
  filesystem-item,
  ? size => integer,
  ? file-version => text,
  ? hash => hash-entry,
  * $$file-extension,
}

directory-entry = {
  filesystem-item,
  path-elements => { path-elements-group },
  * $$directory-extension,
}

process-entry = {
  global-attributes,
  process-name => text,
  ? pid => integer,
  * $$process-extension,
}

resource-entry = {
  global-attributes,
  type => text,
  * $$resource-extension,
}

directory = 16
file = 17
process = 18
resource = 19
size = 20
file-version = 21
key = 22
location = 23
fs-name = 24
root = 25
path-elements = 26
process-name = 27
pid = 28
type = 29

The following describes each member of the groups and maps illustrated above.

  • filesystem-item: A list of common items used for representing the filesystem root, relative location, name, and significance of a file or directory item.
  • global-attributes: The global-attributes group described in Section 2.5.
  • directory (index 16): A directory item allows child directory and file items to be defined within a directory hierarchy for the software component.
  • file (index 17): A file item allows details about a file to be provided for the software component.
  • process (index 18): A process item allows details to be provided about the runtime behavior of the software component, such as information that will appear in a process listing on an endpoint.
  • resource (index 19): A resource item can be used to provide details about an artifact or capability expected to be found on an endpoint or evidence collected related to the software component. This can be used to represent concepts not addressed directly by the directory, file, or process items. Examples include: registry keys, bound ports, etc. The equivalent construct in [SWID] is currently under specified. As a result, this item might be further defined through extension in the future.
  • size (index 20): The file's size in bytes.
  • file-version (index 21): The file's version as reported by querying information on the file from the operating system.
  • key (index 22): A boolean value indicating if a file or directory is significant or required for the software component to execute or function properly. These are files or directories that can be used to affirmatively determine if the software component is installed on an endpoint.
  • location (index 23): The filesystem path where a file is expected to be located when installed or copied. The location MUST be either relative to the location of the parent directory item (preferred) or relative to the location of the CoSWID tag if no parent is defined. The location MUST NOT include a file's name, which is provided by the fs-name item.
  • fs-name (index 24): The name of the directory or file without any path information.
  • root (index 25): A filesystem-specific name for the root of the filesystem. The location item is considered relative to this location if specified. If not provided, the value provided by the location item is expected to be relative to its parent or the location of the CoSWID tag if no parent is provided.
  • path-elements (index 26): This group allows a hierarchy of directory and file items to be defined in payload or evidence items.
  • process-name (index 27): The software component's process name as it will appear in an endpoint's process list.
  • pid (index 28): The process ID identified for a running instance of the software component in the endpoint's process list. This is used as part of the evidence item.
  • type (index 29): A string indicating the type of resource.
  • $$resource-collection-extension: This CDDL socket can be used to extend the resource-collection group model. This can be used to add new specialized types of resources. See Section 2.2.
  • $$file-extension: This CDDL socket can be used to extend the file-entry group model. See Section 2.2.
  • $$directory-extension: This CDDL socket can be used to extend the directory-entry group model. See Section 2.2.
  • $$process-extension: This CDDL socket can be used to extend the process-entry group model. See Section 2.2.
  • $$resource-extension: This CDDL socket can be used to extend the resource-entry group model. See Section 2.2.

2.9.3. The payload-entry Map

The CDDL for the payload-entry map follows:

payload-entry = {
  global-attributes,
  resource-collection,
  * $$payload-extension,
}

The following describes each child item of this group.

  • global-attributes: The global-attributes group described in Section 2.5.
  • resource-collection: The resource-collection group described in Section 2.9.2.
  • $$payload-extension: This CDDL socket can be used to extend the payload-entry group model. See Section 2.2.

2.9.4. The evidence-entry Map

The CDDL for the evidence-entry map follows:

evidence-entry = {
  global-attributes,
  resource-collection,
  ? date => time,
  ? device-id => text,
  * $$evidence-extension,
}

date = 35
device-id = 36

The following describes each child item of this group.

  • global-attributes: The global-attributes group described in Section 2.5.
  • resource-collection: The resource-collection group described in Section 2.9.2.
  • date (index 35): The date and time the information was collected pertaining to the evidence item.
  • device-id (index 36): The endpoint's string identifier from which the evidence was collected.
  • $$evidence-extension: This CDDL socket can be used to extend the evidence-entry group model. See Section 2.2.

2.10. 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-swid-tag = {
  global-attributes,
  tag-id => text / bstr .size 16,
  tag-version => integer,
  ? corpus => bool,
  ? patch => bool,
  ? supplemental => bool,
  software-name => text,
  ? software-version => text,
  ? version-scheme => $version-scheme,
  ? media => text,
  ? software-meta => software-meta-entry / [ 2* software-meta-entry ],
  entity => entity-entry / [ 2* entity-entry ],
  ? link => link-entry / [ 2* link-entry ],
  ? (( payload => payload-entry ) // ( evidence => evidence-entry )),
  * $$coswid-extension,
}

any-uri = text
label = text / int

$version-scheme /= multipartnumeric
$version-scheme /= multipartnumeric-suffix
$version-scheme /= alphanumeric
$version-scheme /= decimal
$version-scheme /= semver
$version-scheme /= uint / text

any-attribute = (
  label => text / int / [ 2* text ] / [ 2* int ]
)

global-attributes = (
  ? lang => text,
  * any-attribute,
)

hash-entry = [
  hash-alg-id: int,
  hash-value: bytes,
]

entity-entry = {
  global-attributes,
  entity-name => text,
  ? reg-id => any-uri,
  role => $role / [ 2* $role ],
  ? thumbprint => hash-entry,
  * $$entity-extension,
}

$role /= tag-creator
$role /= software-creator
$role /= aggregator
$role /= distributor
$role /= licensor
$role /= maintainer
$role /= uint / text

link-entry = {
  global-attributes,
  ? artifact => text,
  href => any-uri,
  ? media => text,
  ? ownership => $ownership,
  rel => $rel,
  ? media-type => text,
  ? use => $use,
  * $$link-extension
}

$ownership /= shared
$ownership /= private
$ownership /= abandon
$ownership /= uint / text

$rel /= ancestor
$rel /= component
$rel /= feature
$rel /= installationmedia
$rel /= packageinstaller
$rel /= parent
$rel /= patches
$rel /= requires
$rel /= see-also
$rel /= supersedes
$rel /= supplemental
$rel /= uint / text

$use /= optional
$use /= required
$use /= recommended
$use /= uint / text

software-meta-entry = {
  global-attributes,
  ? activation-status => text,
  ? channel-type => text,
  ? colloquial-version => text,
  ? description => text,
  ? edition => text,
  ? entitlement-data-required => bool,
  ? entitlement-key => text,
  ? generator => text,
  ? persistent-id => text,
  ? product => text,
  ? product-family => text,
  ? revision => text,
  ? summary => text,
  ? unspsc-code => text,
  ? unspsc-version => text,
  * $$software-meta-extension,
}

path-elements-group = ( ? directory => directory-entry / [ 2* directory-entry ],
                        ? file => file-entry / [ 2* file-entry ],
                      )

resource-collection = (
  path-elements-group,
  ? process => process-entry / [ 2* process-entry ],
  ? resource => resource-entry / [ 2* resource-entry ],
  * $$resource-collection-extension,
)

file-entry = {
  filesystem-item,
  ? size => uint,
  ? file-version => text,
  ? hash => hash-entry,
  * $$file-extension,
}

directory-entry = {
  filesystem-item,
  ? path-elements => { path-elements-group },
  * $$directory-extension,
}

process-entry = {
  global-attributes,
  process-name => text,
  ? pid => integer,
  * $$process-extension,
}

resource-entry = {
  global-attributes,
  type => text,
  * $$resource-extension,
}

filesystem-item = (
  global-attributes,
  ? key => bool,
  ? location => text,
  fs-name => text,
  ? root => text,
)

payload-entry = {
  global-attributes,
  resource-collection,
  * $$payload-extension,
}

evidence-entry = {
  global-attributes,
  resource-collection,
  ? date => time,
  ? device-id => text,
  * $$evidence-extension,
}

; "global map member" integer indexes
tag-id = 0
software-name = 1
entity = 2
evidence = 3
link = 4
software-meta = 5
payload = 6
hash = 7
corpus = 8
patch = 9
media = 10
supplemental = 11
tag-version = 12
software-version = 13
version-scheme = 14
lang = 15
directory = 16
file = 17
process = 18
resource = 19
size = 20
file-version = 21
key = 22
location = 23
fs-name = 24
root = 25
path-elements = 26
process-name = 27
pid = 28
type = 29
entity-name = 31
reg-id = 32
role = 33
thumbprint = 34
date = 35
device-id = 36
artifact = 37
href = 38
ownership = 39
rel = 40
media-type = 41
use = 42
activation-status = 43
channel-type = 44
colloquial-version = 45
description = 46
edition = 47
entitlement-data-required = 48
entitlement-key = 49
generator = 50
persistent-id = 51
product = 52
product-family = 53
revision = 54
summary = 55
unspsc-code = 56
unspsc-version = 57

; "version-scheme" integer indexes
multipartnumeric = 1
multipartnumeric-suffix = 2
alphanumeric = 3
decimal = 4
semver = 16384

; "role" integer indexes
tag-creator=1
software-creator=2
aggregator=3
distributor=4
licensor=5
maintainer=6

; "ownership" integer indexes
shared=1
private=2
abandon=3

; "rel" integer indexes
ancestor=1
component=2
feature=3
installationmedia=4
packageinstaller=5
parent=6
patches=7
requires=8
see-also=9
supersedes=10
; supplemental=11 ; this is already defined earlier

; "use" integer indexes
optional=1
required=2
recommended=3

3. Determining the Type of CoSWID

The operational model for SWID and CoSWID tags was introduced in Section 1.1, which described four different CoSWID tag types. The following additional rules apply to the use of CoSWID tags to ensure that created tags properly identify the tag type.

The first matching rule MUST determine the type of the CoSWID tag.

  1. Primary Tag: A CoSWID tag MUST be considered a primary tag if the corpus, patch, and supplemental items are "false".
  2. Supplemental Tag: A CoSWID tag MUST be considered a supplemental tag if the supplemental item is set to "true".
  3. Corpus Tag: A CoSWID tag MUST be considered a corpus tag if the corpus item is "true".
  4. Patch Tag: A CoSWID tag MUST be considered a patch tag if the patch item is "true".

Note: Multiple of the corpus, patch, and supplemental items can have values set as "true". The rules above provide a means to determine the tag's type in such a case. For example, a SWID or CoSWID tag for a patch installer might have both corpus and patch items set to "true". In such a case, the tag is a "Corpus Tag". The tag installed by this installer would have only the patch item set to "true", making the installed tag type a "Patch Tag".

4. CoSWID Indexed Label Values

4.1. Version Scheme

The following table contains a set of values for use in the concise-swid-tag group's version-scheme item. These values match the version schemes defined in the ISO/IEC 19770-2:2015 [SWID] specification. Index value indicates the value to use as the version-scheme item's value. The Version Scheme Name provides human-readable text for the value. The Definition describes the syntax of allowed values for each entry.

Table 3: Version Scheme Values
Index Version Scheme Name Definition
1 multipartnumeric 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)
2 multipartnumeric+suffix Numbers separated by dots, where the numbers are interpreted as integers with an additional textual suffix (e.g., 1.2.3a)
3 alphanumeric Strictly a string, sorting is done alphanumerically
4 decimal A floating point number (e.g., 1.25 is less than 1.3)
16384 semver Follows the [SEMVER] specification

The values above are registered in the IANA "SWID/CoSWID Version Scheme Value" registry defined in section Section 5.2.4. Additional entries will likely be registered over time in this registry.

These version schemes have partially overlapping value spaces. The following gudelines help to ensure that the most specific version-scheme is used:

  • "decimal" and "multipartnumeric" partially overlap in their value space when a value matches a decimal number . When a corresponding software-version item's value falls within this overlapping value space, the "decimal" version scheme SHOULD be used.
  • "multipartnumeric" and "semver" partially overlap in their value space when a "multipartnumeric" value matches the semantic versioning syntax. When a corresponding software-version item's value falls within this overlapping value space, the "semver" version scheme SHOULD be used.
  • "alphanumeric" and other version schemes might overlap in their value space. When a corresponding software-version item's value falls within this overlapping value space, the other version scheme SHOULD be used instead of "alphanumeric".

4.2. Entity Role Values

The following table indicates the index value to use for the entity-entry group's role item (see Section 2.6). These values match the entity roles defined in the ISO/IEC 19770-2:2015 [SWID] specification. The "Index" value indicates the value to use as the role item's value. The "Role Name" provides human-readable text for the value. The "Definition" describes the semantic meaning of each entry.

Table 4: Entity Role Values
Index Role Name Definition
1 tagCreator The person or organization that created the containing SWID or CoSWID tag
2 softwareCreator The person or organization entity that created the software component.
3 aggregator From [SWID], "An organization or system that encapsulates software from their own and/or other organizations into a different distribution process (as in the case of virtualization), or as a completed system to accomplish a specific task (as in the case of a value added reseller)."
4 distributor From [SWID], "An entity that furthers the marketing, selling and/or distribution of software from the original place of manufacture to the ultimate user without modifying the software, its packaging or its labelling."
5 licensor From [SAM] as "software licensor", a "person or organization who owns or holds the rights to issue a software license for a specific software [component]"
6 maintainer The person or organization that is responsible for coordinating and making updates to the source code for the software component. This SHOULD be used when the "maintainer" is a different person or organization than the original "softwareCreator".

The values above are registered in the IANA "SWID/CoSWID Entity Role Value" registry defined in section Section 5.2.5. Additional values will likely be registered over time. Additionally, the index values 128 through 255 and the name prefix "x_" have been reserved for private use.

5. IANA Considerations

This document has a number of IANA considerations, as described in the following subsections. In summary, 6 new registries are established with this request, with initial entries provided for each registry. New values for 5 other registries are also requested.

5.1. CoSWID Items Registry

This registry uses integer values as index values in CBOR maps.

This document defines a new registry titled "CoSWID Items". Future registrations for this registry are to be made based on [RFC8126] as follows:

Table 8: CoSWID Items Registration Proceedures
Range Registration Procedures
0-32767 Standards Action
32768-4294967295 Specification Required

All negative values are reserved for Private Use.

Initial registrations for the "CoSWID Items" registry are provided below. Assignments consist of an integer index value, the item name, and a reference to the defining specification.

Table 9: CoSWID Items Inital Registrations
Index Item Name Specification
0 tag-id RFC-AAAA
1 software-name RFC-AAAA
2 entity RFC-AAAA
3 evidence RFC-AAAA
4 link RFC-AAAA
5 software-meta RFC-AAAA
6 payload RFC-AAAA
7 hash RFC-AAAA
8 corpus RFC-AAAA
9 patch RFC-AAAA
10 media RFC-AAAA
11 supplemental RFC-AAAA
12 tag-version RFC-AAAA
13 software-version RFC-AAAA
14 version-scheme RFC-AAAA
15 lang RFC-AAAA
16 directory RFC-AAAA
17 file RFC-AAAA
18 process RFC-AAAA
19 resource RFC-AAAA
20 size RFC-AAAA
21 file-version RFC-AAAA
22 key RFC-AAAA
23 location RFC-AAAA
24 fs-name RFC-AAAA
25 root RFC-AAAA
26 path-elements RFC-AAAA
27 process-name RFC-AAAA
28 pid RFC-AAAA
29 type RFC-AAAA
31 entity-name RFC-AAAA
32 reg-id RFC-AAAA
33 role RFC-AAAA
34 thumbprint RFC-AAAA
35 date RFC-AAAA
36 device-id RFC-AAAA
37 artifact RFC-AAAA
38 href RFC-AAAA
39 ownership RFC-AAAA
40 rel RFC-AAAA
41 media-type RFC-AAAA
42 use RFC-AAAA
43 activation-status RFC-AAAA
44 channel-type RFC-AAAA
45 colloquial-version RFC-AAAA
46 description RFC-AAAA
47 edition RFC-AAAA
48 entitlement-data-required RFC-AAAA
49 entitlement-key RFC-AAAA
50 generator RFC-AAAA
51 persistent-id RFC-AAAA
52 product RFC-AAAA
53 product-family RFC-AAAA
54 revision RFC-AAAA
55 summary RFC-AAAA
56 unspsc-code RFC-AAAA
57 unspsc-version RFC-AAAA
58-4294967295 Unassigned  

5.2. SWID/CoSWID Value Registries

The following IANA registries provide a mechanism for new values to be added over time to common enumerations used by SWID and CoSWID.

5.2.1. Registration Proceedures

The following registries allow for the registration of index values and names. New registrations will be permitted through either the Standards Action policy or the Specification Required policy [BCP26]. The latter SHOULD be used only for registrations requested by SDOs outside the IETF. New index values will be provided on a First Come First Served as defined by [BCP26].

The following registries also reserve the integer-based index values in the range of -1 to -256 for private use as defined by [BCP26] in section 4.1. This allows values -1 to -24 to be expressed as a single uint_8t in CBOR, and values -25 to -256 to be expressed using an additional uint_8t in CBOR.

5.2.2. Private Use of Index and Name Values

The integer-based index values in the private use range (-1 to -256) are intended for testing purposes and closed environments; values in other ranges SHOULD NOT be assigned for testing.

For names that correspond to private use index values, an Internationalized Domain Name prefix MUST be used to prevent name conflicts using the form:

domain.prefix-name

Where "domain.prefix" MUST be a valid Internationalized Domain Name as defined by [RFC5892], and "name" MUST be a unique name within the namespace defined by the "domain.prefix". Use of a prefix in this way allows for a name to be used initially in the private use range, and to be registered at a future point in time. This is consistent with the guidance in [BCP178].

5.2.3. Expert Review Guidelines

Designated experts MUST ensure that new registration requests meet the following additional guidelines:

  • The requesting specification MUST provide a clear semantic definition for the new entry. This definition MUST clearly differentiate the requested entry from other previously registered entries.
  • The requesting specification MUST describe the intended use of the entry, including any co-constraints that exist between the use of the entry's index value or name, and other values defined within the SWID/CoSWID model.
  • Index values and names outside the private use space MUST NOT be used without registration. This is considered squatting and SHOULD be avoided. Designated experts MUST ensure that reviewed specifications register all appropriate index values and names.
  • Standards track documents MAY include entries registered in the range reserved for entries under the Specification Required policy. This can occur when a standards track document provides further guidance on the use of index values and names that are in common use, but were not registered with IANA. This situation SHOULD be avoided.
  • All registered names MUST be valid according to the XML Schema NMTOKEN data type (see [W3C.REC-xmlschema-2-20041028] section 3.3.4). This ensures that registered names are compatible with the SWID format [SWID] where they are used.
  • Registration of vanity names SHOULD be discouraged. The requesting specification MUST provide a description of how a requested name will allow for use by multiple stakeholders.

5.2.4. SWID/CoSWID Version Scheme Value Registry

This document establishes a new registry titled "SWID/CoSWID Version Scheme Values". This registry provides index values for use as version-scheme item values in this document and version scheme names for use in [SWID].

[TO BE REMOVED: This registration should take place at the following location: https://www.iana.org/assignments/swid]

This registry uses the registration proceedures defined in Section 5.2.1 with the following associated ranges:

Table 10: CoSWID Version Scheme Registration Proceedures
Range Registration Procedures
0-16383 Standards Action
16384-65535 Specification Required

Assignments MUST consist of an integer Index value, the Version Scheme Name, and a reference to the defining specification.

Initial registrations for the "SWID/CoSWID Version Scheme Value" registry are provided below, which are derived from the textual version scheme names defined in [SWID].

Table 11: CoSWID Version Scheme Inital Registrations
Index Version Scheme Name Specification
0 Reserved  
1 multipartnumeric See Section 4.1
2 multipartnumeric+suffix See Section 4.1
3 alphanumeric See Section 4.1
4 decimal See Section 4.1
5-16383 Unassigned  
16384 semver [SEMVER]
16385-65535 Unassigned  

Registrations MUST conform to the expert review guidelines defined in Section 5.2.3.

Designated experts MUST also ensure that newly requested entries define a value space for the corresponding version item that is unique from other previously registered entries. Note: The inital registrations violate this requirement, but are included for backwards compatibility with [SWID]. Guidelines on how to deconflict these value spaces are defined in section Section 4.1.

5.2.5. SWID/CoSWID Entity Role Value Registry

This document establishes a new registry titled "SWID/CoSWID Entity Role Values". This registry provides index values for use as entity-entry role item values in this document and entity role names for use in [SWID].

[TO BE REMOVED: This registration should take place at the following location: https://www.iana.org/assignments/swid]

This registry uses the registration proceedures defined in Section 5.2.1 with the following associated ranges:

Table 12: CoSWID Entity Role Registration Proceedures
Range Registration Procedures
0-127 Standards Action
128-255 Specification Required

Assignments consist of an integer Index value, a Role Name, and a reference to the defining specification.

Initial registrations for the "SWID/CoSWID Entity Role Value" registry are provided below, which are derived from the textual entity role names defined in [SWID].

Table 13: CoSWID Entity Role Inital Registrations
Index Role Name Specification
0 Reserved  
1 tagCreator See Section 4.2
2 softwareCreator See Section 4.2
3 aggregator See Section 4.2
4 distributor See Section 4.2
5 licensor See Section 4.2
6 maintainer See Section 4.2
7-255 Unassigned  

Registrations MUST conform to the expert review guidlines defined in Section 5.2.3.

5.3. swid+cbor Media Type Registration

IANA is requested to add the following to the IANA "Media Types" registry.

Type name: application

Subtype name: swid+cbor

Required parameters: none

Optional parameters: none

Encoding considerations: Must be encoded as using [RFC7049]. See RFC-AAAA for details.

Security considerations: See Section 6 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-7049 section 7.5.

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

5.4. 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]:

Table 20: CoAP Content-Format IDs
Media type Encoding ID Reference
application/swid+cbor - TBD1 RFC-AAAA

5.5. CBOR Tag Registration

IANA is requested to allocate a tag in the "CBOR Tags" registry, preferably with the specific value requested:

Table 21: CoSWID CBOR Tag
Tag Data Item Semantics
1398229316 map Concise Software Identifier (CoSWID) [RFC-AAAA]

5.6. URI Scheme Registrations

The ISO 19770-2:2015 SWID specification describes use of the "swid" and "swidpath" URI schemes, which are currently in use in implementations. This document continues this use for CoSWID. The following subsections provide registrations for these schemes in to ensure that a permanent registration exists for these schemes that is suitable for use in the SWID and CoSWID specifications.

5.6.1. "swid" URI Scheme Registration

There is a need for a scheme name that can be used in URIs that point to a specific SWID/CoSWID tag by that tag's tag-id, such as the use of the link entry as described in section Section 2.7) of this document. Since this scheme is used in a standards track document and an ISO standard, this scheme needs to be used without fear of conflicts with current or future actual schemes. The scheme "swid" is hereby registered as a 'permanent' scheme for that purpose.

The "swid" scheme is specified as follows:

Scheme syntax: The scheme speific part consists of a SWID or CoSWID tag's tag-id that is URI encoded according to [RFC3986] section 2.1. The following expression is a valid example:

<swid:2df9de35-0aff-4a86-ace6-f7dddd1ade4c>

Scheme semantics: URIs in the "swid" scheme are to be used to reference a SWID or CoSWID tag by its tag-id. A tag-id referenced in this way can be used to indentify the tag resource in the context of where it is referenced from. For example, when a tag is installed on a given device, that tag can reference related tags on the same device using this URI scheme.

Encoding considerations: See Section 2.5 of [RFC3986] for guidelines.

Interoperability considerations: None.

Security considerations: None.

5.6.2. "swidpath" URI Scheme Registration

There is a need for a scheme name that can be used in URIs to indentify a collection of specific SWID/CoSWID tags with data elements that match an XPath expression, such as the use of the link entry as described in section Section 2.7) of this document. Since this scheme is used in a standards track document and an ISO standard, this scheme needs to be used without fear of conflicts with current or future actual schemes. The scheme "swidpath" is hereby registered as a 'permanent' scheme for that purpose.

The "swidpath" scheme is specified as follows:

Scheme syntax: The scheme speific part consists of an XPath expression as defined by [W3C.REC-xpath20-20101214]. The included XPath expression will be URI encoded according to [RFC3986] section 2.1.

Scheme semantics: URIs in the "swidpath" scheme are to be used specify the data that must be found in a given SWID/CoSWID tag for that tag to be considered a matching tag to be included in the identified tag collection. Tags to be evaluated include all tags in the context of where the tag is referenced from. For example, when a tag is installed on a given device, that tag can reference related tags on the same device using this URI scheme. A tag is matching if the XPath evaluation result value has an effective boolean value of "true" according to [W3C.REC-xpath20-20101214] section 2.4.3. rence related tags on the same device using this URI scheme.

Encoding considerations: See Section 2.5 of [RFC3986] for guidelines.

Interoperability considerations: None.

Security considerations: None.

5.7. CoSWID Model for use in SWIMA Registration

The Software Inventory Message and Attributes (SWIMA) for PA-TNC specification [RFC8412] defines a standardized method for collecting an endpoint device's software inventory. A CoSWID can provide evidence of software installation which can then be used and exchanged with SWIMA. This registration adds a new entry to the IANA "Software Data Model Types" registry defined by [RFC8412] to support CoSWID use in SWIMA as follows:

Pen: 0

Integer: TBD2

Name: Concise Software Identifier (CoSWID)

Defining Specification: RFC-AAAA

Deriving Software Identifiers:

A Software Identifier generated from a CoSWID tag is expressed as a concatenation of the form:

TAG_CREATOR_REGID "_" "_" UNIQUE_ID

Where TAG_CREATOR_REGID is the reg-id ietm value of the tag's entity item having the role value of 1 (corresponding to "tag creator"), and the UNIQUE_ID is the same tag's tag-id item. If the tag-id item's value is expressed as a 16 byte binary string, the UNIQUE_ID MUST be represented using the UUID string representation defined in [RFC4122] including the "urn:uuid:" prefix.

The TAG_CREATOR_REGID and the UNIQUE_ID are connected with a double underscore (_), without any other connecting character or whitespace.

6. 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/CoSWID 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/CoSWID tags focus on the application of SWID/CoSWID tags to address security challenges, and the possible disclosure of the results of those applications.

A tag is considered "authoritative" if the SWID/CoSWID tag was created by the software provider. An authoritative SWID/CoSWID tag contains information about a software component provided by the maintainer of the software component, who is expected to be an expert in their own software. Thus, authoritative SWID/CoSWID tags can be trusted to represent authoritative information about the software component.

A signed SWID/CoSWID tag (see Appendix A) whose signature has been validated can be relied upon to be unchanged since it was signed. By contrast, the data contained in unsigned tags cannot be trusted to be unmodified.

When an authoritative tag is signed, the software provider can be authenticated as the originator of the signature. Having a signed authoritative SWID/CoSWID 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.

SWID/CoSWID 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/CoSWID tags can be easier to add or remove. On such systems, it can be possible to add or remove SWID/CoSWID 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/CoSWID tags, so products can be present on an endpoint without providing a corresponding SWID tag. As such, any collection of SWID/CoSWID tags cannot automatically be assumed to represent either a complete or fully accurate representation of the software inventory of the endpoint. However, especially on endpoint devices that more strictly control the ability to add or remove applications, SWID/CoSWID tags are an easy way to provide an preliminary understanding of that endpoint's software inventory.

Any report of an endpoint's SWID/CoSWID 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/CoSWID 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. For this reason, it is important to protect the confidentiality of SWID/CoSWID tag information that has been collected from an endpoint, not because those tags individually contain sensitive information, but because the collection of SWID/CoSWID tags and their association with an endpoint reveals information about that endpoint's attack surface.

Finally, both the ISO-19770-2:2015 XML schema SWID definition and the CoSWID data definition allow for the construction of "infinite" tags with link item loops or tags that contain malicious content with the intent of creating non-deterministic states during validation or processing of those tags. While software providers are unlikely to do this, SWID/CoSWID tags can be created by any party and the SWID/CoSWID tags collected from an endpoint could contain a mixture of vendor and non-vendor created tags. For this reason, tools that consume SWID/CoSWID tags ought to treat the tag contents as potentially malicious and employ input sanitizing and loop detection on the tags they ingest.

7. Acknowledgments

This document draws heavily on the concepts defined in the ISO/IEC 19770-2:2015 specification. The authors of this document are grateful for the prior work of the 19770-2 contributors.

We are also grateful to the careful reviews provided by ...

8. Change Log

[THIS SECTION TO BE REMOVED BY THE RFC EDITOR.]

Changes from version 12 to version 14:

Changes in version 12:

Changes from version 03 to version 11:

Changes from version 02 to version 03:

Changes from version 01 to version 02:

Changes from version 00 to version 01:

Changes since adopted as a WG I-D -00:

Changes from version 06 to version 07:

Changes from version 05 to version 06:

Changes from version 04 to version 05:

Changes from version 03 to version 04:

Changes from version 02 to version 03:

Changes from version 01 to version 02:

Changes from version 00 to version 01:

9. References

9.1. Normative References

[BCP178]
Saint-Andre, P., Crocker, D., and M. Nottingham, "Deprecating the "X-" Prefix and Similar Constructs in Application Protocols", BCP 178, RFC 6648, DOI 10.17487/RFC6648, , <https://www.rfc-editor.org/info/rfc6648>.
[BCP26]
Cotton, M., Leiba, B., and T. Narten, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 8126, DOI 10.17487/RFC8126, , <https://www.rfc-editor.org/info/rfc8126>.
[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/info/rfc2119>.
[RFC3629]
Yergeau, F., "UTF-8, a transformation format of ISO 10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, , <https://www.rfc-editor.org/info/rfc3629>.
[RFC3986]
Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, DOI 10.17487/RFC3986, , <https://www.rfc-editor.org/info/rfc3986>.
[RFC5198]
Klensin, J. and M. Padlipsky, "Unicode Format for Network Interchange", RFC 5198, DOI 10.17487/RFC5198, , <https://www.rfc-editor.org/info/rfc5198>.
[RFC5646]
Phillips, A., Ed. and M. Davis, Ed., "Tags for Identifying Languages", BCP 47, RFC 5646, DOI 10.17487/RFC5646, , <https://www.rfc-editor.org/info/rfc5646>.
[RFC5892]
Faltstrom, P., Ed., "The Unicode Code Points and Internationalized Domain Names for Applications (IDNA)", RFC 5892, DOI 10.17487/RFC5892, , <https://www.rfc-editor.org/info/rfc5892>.
[RFC7049]
Bormann, C. and P. Hoffman, "Concise Binary Object Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049, , <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, , <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, , <https://www.rfc-editor.org/info/rfc8126>.
[RFC8152]
Schaad, J., "CBOR Object Signing and Encryption (COSE)", RFC 8152, DOI 10.17487/RFC8152, , <https://www.rfc-editor.org/info/rfc8152>.
[RFC8174]
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/info/rfc8174>.
[RFC8288]
Nottingham, M., "Web Linking", RFC 8288, DOI 10.17487/RFC8288, , <https://www.rfc-editor.org/info/rfc8288>.
[RFC8412]
Schmidt, C., Haynes, D., Coffin, C., Waltermire, D., and J. Fitzgerald-McKay, "Software Inventory Message and Attributes (SWIMA) for PA-TNC", RFC 8412, DOI 10.17487/RFC8412, , <https://www.rfc-editor.org/info/rfc8412>.
[RFC8610]
Birkholz, H., Vigano, C., and C. Bormann, "Concise Data Definition Language (CDDL): A Notational Convention to Express Concise Binary Object Representation (CBOR) and JSON Data Structures", RFC 8610, DOI 10.17487/RFC8610, , <https://www.rfc-editor.org/info/rfc8610>.
[SAM]
"Information technology - Software asset management - Part 5: Overview and vocabulary", ISO/IEC 19770-5:2015, .
[SEMVER]
Preston-Werner, T., "Semantic Versioning 2.0.0", , <https://semver.org/spec/v2.0.0.html>.
[SWID]
"Information technology - Software asset management - Part 2: Software identification tag", ISO/IEC 19770-2:2015, .
[W3C.REC-css3-mediaqueries-20120619]
Rivoal, F., "Media Queries", World Wide Web Consortium Recommendation REC-css3-mediaqueries-20120619, , <http://www.w3.org/TR/2012/REC-css3-mediaqueries-20120619>.
[W3C.REC-xmlschema-2-20041028]
Biron, P. and A. Malhotra, "XML Schema Part 2: Datatypes Second Edition", World Wide Web Consortium Recommendation REC-xmlschema-2-20041028, , <http://www.w3.org/TR/2004/REC-xmlschema-2-20041028>.
[W3C.REC-xpath20-20101214]
Berglund, A., Boag, S., Chamberlin, D., Fernandez, M., Kay, M., Robie, J., and J. Simeon, "XML Path Language (XPath) 2.0 (Second Edition)", World Wide Web Consortium Recommendation REC-xpath20-20101214, , <http://www.w3.org/TR/2010/REC-xpath20-20101214>.
[X.1520]
"Recommendation ITU-T X.1520 (2014), Common vulnerabilities and exposures", .

9.2. Informative References

[CamelCase]
"UpperCamelCase", , <http://wiki.c2.com/?CamelCase>.
[I-D.birkholz-rats-tuda]
Fuchs, A., Birkholz, H., McDonald, I., and C. Bormann, "Time-Based Uni-Directional Attestation", Work in Progress, Internet-Draft, draft-birkholz-rats-tuda-02, , <http://www.ietf.org/internet-drafts/draft-birkholz-rats-tuda-02.txt>.
[KebabCase]
"KebabCase", , <http://wiki.c2.com/?KebabCase>.
[RFC4122]
Leach, P., Mealling, M., and R. Salz, "A Universally Unique IDentifier (UUID) URN Namespace", RFC 4122, DOI 10.17487/RFC4122, , <https://www.rfc-editor.org/info/rfc4122>.
[RFC8322]
Field, J., Banghart, S., and D. Waltermire, "Resource-Oriented Lightweight Information Exchange (ROLIE)", RFC 8322, DOI 10.17487/RFC8322, , <https://www.rfc-editor.org/info/rfc8322>.
[RFC8520]
Lear, E., Droms, R., and D. Romascanu, "Manufacturer Usage Description Specification", RFC 8520, DOI 10.17487/RFC8520, , <https://www.rfc-editor.org/info/rfc8520>.
[SWID-GUIDANCE]
Waltermire, D., Cheikes, B.A., Feldman, L., and G. Witte, "Guidelines for the Creation of Interoperable Software Identification (SWID) Tags", NISTIR 8060, , <https://doi.org/10.6028/NIST.IR.8060>.

Appendix A. 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 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 tags.

<CODE BEGINS>
signed-coswid = #6.18(COSE-Sign1-coswid)

cose-label = int / tstr
cose-values = any

protected-signed-coswid-header = {
    1 => int,                      ; algorithm identifier
    3 => "application/swid+cbor",
    4 => bstr,                     ; key identifier
    * cose-label => cose-values,
}

unprotected-signed-coswid-header = {
    * cose-label => cose-values,
}

COSE-Sign1-coswid = [
    protected: bstr .cbor protected-signed-coswid-header,
    unprotected: unprotected-signed-coswid-header,
    payload: bstr .cbor concise-swid-tag,
    signature: bstr,
]

<CODE ENDS>

Optionally, the COSE_Sign structure that allows for more than one signature to be applied to a CoSWID tag MAY be used. The corresponding usage scenarios are domain-specific and require well-defined application guidance. Representation of the corresponding guidance is out-of-scope of this document.

Additionally, the COSE Header counter signature MAY be used as an attribute in the unprotected header map of the COSE envelope of a CoSWID. The application of counter signing enables second parties to provide a signature on a signature allowing for a proof that a signature existed at a given time (i.e., a timestamp).

Authors' Addresses

Henk Birkholz
Fraunhofer SIT
Rheinstrasse 75
64295 Darmstadt
Germany
Jessica Fitzgerald-McKay
Department of Defense
9800 Savage Road
Ft. Meade, Maryland
United States of America
Charles Schmidt
The MITRE Corporation
202 Burlington Road
Bedford, Maryland 01730
United States of America
David Waltermire
National Institute of Standards and Technology
100 Bureau Drive
Gaithersburg, Maryland 20877
United States of America