Internet Engineering Task Force (IETF) P. Hoffman
Request for Comments: 9157 ICANN
Updates: 5155, 6014, 8624 November 2021
Category: Standards Track
ISSN: 2070-1721
Revised IANA Considerations for DNSSEC
Abstract
This document changes the review requirements needed to get DNSSEC
algorithms and resource records added to IANA registries. It updates
RFC 6014 to include hash algorithms for Delegation Signer (DS)
records and NextSECure version 3 (NSEC3) parameters (for Hashed
Authenticated Denial of Existence). It also updates RFCs 5155 and
6014, which have requirements for DNSSEC algorithms, and updates RFC
8624 to clarify the implementation recommendation related to the
algorithms described in RFCs that are not on the standards track.
The rationale for these changes is to bring the requirements for DS
records and hash algorithms used in NSEC3 in line with the
requirements for all other DNSSEC algorithms.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9157.
Copyright Notice
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Table of Contents
1. Introduction
1.1. Requirements Language
2. Update to RFC 6014
3. Update to RFC 8624
4. IANA Considerations
5. Security Considerations
6. References
6.1. Normative References
6.2. Informative References
Acknowledgements
Author's Address
1. Introduction
DNSSEC is primarily described in [RFC4033], [RFC4034], and [RFC4035].
DNSSEC commonly uses another resource record beyond those defined in
[RFC4034]: NSEC3 [RFC5155]. DS resource records were originally
defined in [RFC3658], and that definition was obsoleted by [RFC4034].
[RFC6014] updates the requirements for how DNSSEC cryptographic
algorithm identifiers in the IANA registries are assigned, reducing
the requirements from "Standards Action" to "RFC Required". However,
the IANA registry requirements for hash algorithms for DS records
[RFC3658] and for the hash algorithms used in NSEC3 records [RFC5155]
are still "Standards Action". This document updates those IANA
registry requirements. (For a reference on how IANA registries can
be updated in general, see [RFC8126].)
1.1. Requirements Language
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. Update to RFC 6014
Section 4 updates [RFC6014] to bring the requirements for DS records
and NSEC3 hash algorithms in line with the rest of the DNSSEC
cryptographic algorithms by allowing any DS hash algorithms, NSEC3
hash algorithms, NSEC3 parameters, and NSEC3 flags that are fully
described in an RFC to have identifiers assigned in the IANA
registries. This is an addition to the IANA considerations in
[RFC6014].
3. Update to RFC 8624
This document updates [RFC8624] for all DNSKEY and DS algorithms that
are not on the standards track.
The second paragraph of Section 1.2 of [RFC8624] currently says:
| This document only provides recommendations with respect to
| mandatory-to-implement algorithms or algorithms so weak that they
| cannot be recommended. Any algorithm listed in the [DNSKEY-IANA]
| and [DS-IANA] registries that are not mentioned in this document
| MAY be implemented. For clarification and consistency, an
| algorithm will be specified as MAY in this document only when it
| has been downgraded from a MUST or a RECOMMENDED to a MAY.
That paragraph is now replaced with the following:
| This document provides recommendations with respect to mandatory-
| to-implement algorithms, algorithms so weak that they cannot be
| recommended, and algorithms defined in RFCs that are not on the
| standards track. Any algorithm listed in the [DNSKEY-IANA] and
| [DS-IANA] registries that are not mentioned in this document MAY
| be implemented. For clarification and consistency, an algorithm
| will be specified as MAY in this document only when it has been
| downgraded from a MUST or a RECOMMENDED to a MAY.
This update is also reflected in the IANA considerations in
Section 4.
4. IANA Considerations
In the "Domain Name System Security (DNSSEC) NextSECure3 (NSEC3)
Parameters" registry, the registration procedure for "DNSSEC NSEC3
Flags", "DNSSEC NSEC3 Hash Algorithms", and "DNSSEC NSEC3PARAM Flags"
has been changed from "Standards Action" to "RFC Required", and this
document has been added as a reference.
In the "DNSSEC Delegation Signer (DS) Resource Record (RR) Type
Digest Algorithms" registry, the registration procedure for "Digest
Algorithms" has been changed from "Standards Action" to "RFC
Required", and this document has been added as a reference.
5. Security Considerations
Changing the requirements for adding security algorithms to IANA
registries as described in this document will make it easier to add
both good and bad algorithms to the registries. It is impossible to
weigh the security impact of those two changes.
Administrators of DNSSEC-signed zones and validating resolvers may
have been making security decisions based on the contents of the IANA
registries. This was a bad idea in the past, and now it is an even
worse idea because there will be more algorithms in those registries
that may not have gone through IETF review. Security decisions about
which algorithms are safe and not safe should be made by reading the
security literature, not by looking in IANA registries.
6. References
6.1. Normative References
[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>.
[RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "DNS Security Introduction and Requirements",
RFC 4033, DOI 10.17487/RFC4033, March 2005,
<https://www.rfc-editor.org/info/rfc4033>.
[RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "Resource Records for the DNS Security Extensions",
RFC 4034, DOI 10.17487/RFC4034, March 2005,
<https://www.rfc-editor.org/info/rfc4034>.
[RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "Protocol Modifications for the DNS Security
Extensions", RFC 4035, DOI 10.17487/RFC4035, March 2005,
<https://www.rfc-editor.org/info/rfc4035>.
[RFC5155] Laurie, B., Sisson, G., Arends, R., and D. Blacka, "DNS
Security (DNSSEC) Hashed Authenticated Denial of
Existence", RFC 5155, DOI 10.17487/RFC5155, March 2008,
<https://www.rfc-editor.org/info/rfc5155>.
[RFC6014] Hoffman, P., "Cryptographic Algorithm Identifier
Allocation for DNSSEC", RFC 6014, DOI 10.17487/RFC6014,
November 2010, <https://www.rfc-editor.org/info/rfc6014>.
[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>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8624] Wouters, P. and O. Sury, "Algorithm Implementation
Requirements and Usage Guidance for DNSSEC", RFC 8624,
DOI 10.17487/RFC8624, June 2019,
<https://www.rfc-editor.org/info/rfc8624>.
6.2. Informative References
[RFC3658] Gudmundsson, O., "Delegation Signer (DS) Resource Record
(RR)", RFC 3658, DOI 10.17487/RFC3658, December 2003,
<https://www.rfc-editor.org/info/rfc3658>.
Acknowledgements
Donald Eastlake, Murray Kucherawy, Dan Harkins, Martin Duke, and
Benjamin Kaduk contributed to this document.
Author's Address
Paul Hoffman
ICANN
Email: paul.hoffman@icann.org