draft-ietf-dnsext-dnssec-bis-updates-04.txt   draft-ietf-dnsext-dnssec-bis-updates-05.txt 
Network Working Group S. Weiler Network Working Group S. Weiler
Internet-Draft SPARTA, Inc Internet-Draft SPARTA, Inc
Updates: 4034, 4035 (if approved) R. Austein Updates: 4034, 4035 R. Austein
Intended status: Informational ISC (if approved) ISC
Expires: April 25, 2007 October 22, 2006 Expires: September 5, 2007 March 4, 2007
Clarifications and Implementation Notes for DNSSECbis Clarifications and Implementation Notes for DNSSECbis
draft-ietf-dnsext-dnssec-bis-updates-04 draft-ietf-dnsext-dnssec-bis-updates-05
Status of this Memo Status of this Memo
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This Internet-Draft will expire on April 25, 2007. This Internet-Draft will expire on September 5, 2007.
Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2006). Copyright (C) The IETF Trust (2007).
Abstract Abstract
This document is a collection of minor technical clarifications to This document is a collection of minor technical clarifications to
the DNSSECbis document set. It is meant to serve as a resource to the DNSSECbis document set. It is meant to serve as a resource to
implementors as well as an interim repository of DNSSECbis errata. implementors as well as an interim repository of DNSSECbis errata.
Proposed additions in future versions
An index sorted by the section of DNSSECbis being clarified.
A list of proposed protocol changes being made in other documents,
such as [RFC4470] and [I-D.ietf-dnsext-nsec3]. This document would
not make those changes, merely provide an index into the documents
that are making changes.
Changes between -02 and -03
Updated references.
Changes between -01 and -02
Added Section 4.4.
Changes between -00 and -01
Document significantly restructured.
Added Section 2.3.
Changes between personal submission and first WG draft
Added Section 2.1 based on namedroppers discussions from March 9-10,
2005.
Added Section 3.4, Section 3.3, Section 4.3, and Section 2.2.
Added the DNSSECbis RFC numbers.
Figured out the confusion in Section 4.1.
Table of Contents Table of Contents
1. Introduction and Terminology . . . . . . . . . . . . . . . . . 4 1. Introduction and Terminology . . . . . . . . . . . . . . . . . 3
1.1. Structure of this Document . . . . . . . . . . . . . . . . 4 1.1. Structure of this Document . . . . . . . . . . . . . . . . 3
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Significant Concerns . . . . . . . . . . . . . . . . . . . . . 4 2. Significant Concerns . . . . . . . . . . . . . . . . . . . . . 3
2.1. Clarifications on Non-Existence Proofs . . . . . . . . . . 4 2.1. Clarifications on Non-Existence Proofs . . . . . . . . . . 3
2.2. Empty Non-Terminal Proofs . . . . . . . . . . . . . . . . 5 2.2. Validating Responses to an ANY Query . . . . . . . . . . . 4
2.3. Validating Responses to an ANY Query . . . . . . . . . . . 5 2.3. Check for CNAMEa . . . . . . . . . . . . . . . . . . . . . 4
3. Interoperability Concerns . . . . . . . . . . . . . . . . . . 5 3. Interoperability Concerns . . . . . . . . . . . . . . . . . . 4
3.1. Unknown DS Message Digest Algorithms . . . . . . . . . . . 5 3.1. Unknown DS Message Digest Algorithms . . . . . . . . . . . 4
3.2. Private Algorithms . . . . . . . . . . . . . . . . . . . . 6 3.2. Private Algorithms . . . . . . . . . . . . . . . . . . . . 5
3.3. Caution About Local Policy and Multiple RRSIGs . . . . . . 6 3.3. Caution About Local Policy and Multiple RRSIGs . . . . . . 5
3.4. Key Tag Calculation . . . . . . . . . . . . . . . . . . . 7 3.4. Key Tag Calculation . . . . . . . . . . . . . . . . . . . 6
3.5. Setting the DO Bit on Replies . . . . . . . . . . . . . . 7 3.5. Setting the DO Bit on Replies . . . . . . . . . . . . . . 6
3.6. Responding to QTYPE=* with the DO Bit Clear . . . . . . . 7 4. Minor Corrections and Clarifications . . . . . . . . . . . . . 6
4. Minor Corrections and Clarifications . . . . . . . . . . . . . 7 4.1. Finding Zone Cuts . . . . . . . . . . . . . . . . . . . . 6
4.1. Finding Zone Cuts . . . . . . . . . . . . . . . . . . . . 7 4.2. Clarifications on DNSKEY Usage . . . . . . . . . . . . . . 6
4.2. Clarifications on DNSKEY Usage . . . . . . . . . . . . . . 8 4.3. Errors in Examples . . . . . . . . . . . . . . . . . . . . 7
4.3. Errors in Examples . . . . . . . . . . . . . . . . . . . . 8 4.4. Errors in Canonical Form Type Code List . . . . . . . . . 7
4.4. Errors in Canonical Form Type Code List . . . . . . . . . 8 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 6. Security Considerations . . . . . . . . . . . . . . . . . . . 8
6. Security Considerations . . . . . . . . . . . . . . . . . . . 9 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 7.1. Normative References . . . . . . . . . . . . . . . . . . . 8
7.1. Normative References . . . . . . . . . . . . . . . . . . . 9 7.2. Informative References . . . . . . . . . . . . . . . . . . 8
7.2. Informative References . . . . . . . . . . . . . . . . . . 10 Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 9
Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11 Intellectual Property and Copyright Statements . . . . . . . . . . 11
Intellectual Property and Copyright Statements . . . . . . . . . . 12
1. Introduction and Terminology 1. Introduction and Terminology
This document lists some minor clarifications and corrections to This document lists some minor clarifications and corrections to
DNSSECbis, as described in [RFC4033], [RFC4034], and [RFC4035]. DNSSECbis, as described in [RFC4033], [RFC4034], and [RFC4035].
It is intended to serve as a resource for implementors and as a It is intended to serve as a resource for implementors and as a
repository of items that need to be addressed when advancing the repository of items that need to be addressed when advancing the
DNSSECbis documents from Proposed Standard to Draft Standard. DNSSECbis documents from Proposed Standard to Draft Standard.
In this version (-01 of the WG document), feedback is particularly
solicited on the structure of the document and whether the text in
the recently added sections is correct and sufficient.
Proposed substantive additions to this document should be sent to the Proposed substantive additions to this document should be sent to the
namedroppers mailing list as well as to the editors of this document. namedroppers mailing list as well as to the editors of this document.
The editors would greatly prefer contributions of text suitable for The editors would greatly prefer contributions of text suitable for
direct inclusion in this document. direct inclusion in this document.
1.1. Structure of this Document 1.1. Structure of this Document
The clarifications to DNSSECbis are sorted according to the editors' The clarifications to DNSSECbis are sorted according to the editors'
impression of their importance, starting with ones which could, if impression of their importance, starting with ones which could, if
ignored, lead to security and stability problems and progressing down ignored, lead to security and stability problems and progressing down
to clarifications that are likely to have little operational impact. to clarifications that are likely to have little operational impact.
Mere typos and awkward phrasings are not addressed unless they could
lead to misinterpretation of the DNSSECbis documents.
1.2. Terminology 1.2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
2. Significant Concerns 2. Significant Concerns
This section provides clarifications that, if overlooked, could lead This section provides clarifications that, if overlooked, could lead
to security issues or major interoperability problems. to security issues or major interoperability problems.
2.1. Clarifications on Non-Existence Proofs 2.1. Clarifications on Non-Existence Proofs
[RFC4035] Section 5.4 slightly underspecifies the algorithm for [RFC4035] Section 5.4 slightly underspecifies the algorithm for
checking non-existence proofs. In particular, the algorithm there checking non-existence proofs. In particular, the algorithm there
might incorrectly allow the NSEC from the parent side of a zone cut might incorrectly allow the NSEC from an ancestor zone to prove the
to prove the non-existence of either other RRs at that name in the non-existence of either other RRs at that name in the child zone or
child zone or other names in the child zone. It might also allow a other names in the child zone. It might also allow a NSEC at the
NSEC at the same name as a DNAME to prove the non-existence of names same name as a DNAME to prove the non-existence of names beneath that
beneath that DNAME. DNAME.
A parent-side delegation NSEC (one with the NS bit set, but no SOA An ancestor delegation NSEC (one with the NS bit set, but no SOA bit
bit set, and with a singer field that's shorter than the owner name) set, and with a singer field that's shorter than the owner name) must
must not be used to assume non-existence of any RRs below that zone not be used to assume non-existence of any RRs below that zone cut
cut (both RRs at that ownername and at ownernames with more leading (both RRs at that ownername and at ownernames with more leading
labels, no matter their content). Similarly, an NSEC with the DNAME labels, no matter their content). Similarly, an NSEC with the DNAME
bit set must not be used to assume the non-existence of any bit set must not be used to assume the non-existence of any
descendant of that NSEC's owner name. descendant of that NSEC's owner name.
2.2. Empty Non-Terminal Proofs 2.2. Validating Responses to an ANY Query
To be written, based on Roy Arends' May 11th message to namedroppers.
The editors are trying to figure out whether what's really required
here is a discussion of the relationship between DNS RCODEs and
DNSSECbis.
2.3. Validating Responses to an ANY Query
[RFC4035] does not address how to validate responses when QTYPE=*. [RFC4035] does not address how to validate responses when QTYPE=*.
As described in Section 6.2.2 of [RFC1034], a proper response to As described in Section 6.2.2 of [RFC1034], a proper response to
QTYPE=* may include a subset of the RRsets at a given name -- it is QTYPE=* may include a subset of the RRsets at a given name -- it is
not necessary to include all RRsets at the QNAME in the response. not necessary to include all RRsets at the QNAME in the response.
When validating a response to QTYPE=*, validate all received RRsets When validating a response to QTYPE=*, validate all received RRsets
that match QNAME and QCLASS. If any of those RRsets fail validation, that match QNAME and QCLASS. If any of those RRsets fail validation,
treat the answer as Bogus. If there are no RRsets matching QNAME and treat the answer as Bogus. If there are no RRsets matching QNAME and
QCLASS, validate that fact using the rules in [RFC4035] Section 5.4 QCLASS, validate that fact using the rules in [RFC4035] Section 5.4
(as clarified in this document). To be clear, a validator must not (as clarified in this document). To be clear, a validator must not
insist on receiving all records at the QNAME in response to QTYPE=*. insist on receiving all records at the QNAME in response to QTYPE=*.
2.3. Check for CNAMEa
Section 5 of [RFC4035] says little about validating responses based
on (or that should be based on) CNAMEs. When validating a NODATA
response, it's important to check the CNAME bit in the NSEC bitmap.
If the CNAME bit is set, the validator MUST validate the CNAME RR and
follow it, as appropriate.
3. Interoperability Concerns 3. Interoperability Concerns
3.1. Unknown DS Message Digest Algorithms 3.1. Unknown DS Message Digest Algorithms
Section 5.2 of [RFC4035] includes rules for how to handle delegations Section 5.2 of [RFC4035] includes rules for how to handle delegations
to zones that are signed with entirely unsupported algorithms, as to zones that are signed with entirely unsupported algorithms, as
indicated by the algorithms shown in those zone's DS RRsets. It does indicated by the algorithms shown in those zone's DS RRsets. It does
not explicitly address how to handle DS records that use unsupported not explicitly address how to handle DS records that use unsupported
message digest algorithms. In brief, DS records using unknown or message digest algorithms. In brief, DS records using unknown or
unsupported message digest algorithms MUST be treated the same way as unsupported message digest algorithms MUST be treated the same way as
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3.5. Setting the DO Bit on Replies 3.5. Setting the DO Bit on Replies
[RFC4035] does not provide any instructions to servers as to how to [RFC4035] does not provide any instructions to servers as to how to
set the DO bit. Some authoritative server implementations have set the DO bit. Some authoritative server implementations have
chosen to copy the DO bit settings from the incoming query to the chosen to copy the DO bit settings from the incoming query to the
outgoing response. Others have chosen to never set the DO bit in outgoing response. Others have chosen to never set the DO bit in
responses. Either behavior is permited. To be clear, in replies to responses. Either behavior is permited. To be clear, in replies to
queries with the DO-bit set servers may or may not set the DO bit. queries with the DO-bit set servers may or may not set the DO bit.
3.6. Responding to QTYPE=* with the DO Bit Clear
To protect resolvers that cannot cope with DNSSEC types, a server
should not include DNSSEC RR types when responding to a query with
QTYPE=* and the DO bit not set.
4. Minor Corrections and Clarifications 4. Minor Corrections and Clarifications
4.1. Finding Zone Cuts 4.1. Finding Zone Cuts
Appendix C.8 of [RFC4035] discusses sending DS queries to the servers Appendix C.8 of [RFC4035] discusses sending DS queries to the servers
for a parent zone. To do that, a resolver may first need to apply for a parent zone. To do that, a resolver may first need to apply
special rules to discover what those servers are. special rules to discover what those servers are.
As explained in Section 3.1.4.1 of [RFC4035], security-aware name As explained in Section 3.1.4.1 of [RFC4035], security-aware name
servers need to apply special processing rules to handle the DS RR, servers need to apply special processing rules to handle the DS RR,
and in some situations the resolver may also need to apply special and in some situations the resolver may also need to apply special
rules to locate the name servers for the parent zone if the resolver rules to locate the name servers for the parent zone if the resolver
does not already have the parent's NS RRset. Section 4.2 of does not already have the parent's NS RRset. Section 4.2 of
[RFC4035] specifies a mechanism for doing that. [RFC4035] specifies a mechanism for doing that.
4.2. Clarifications on DNSKEY Usage 4.2. Clarifications on DNSKEY Usage
Questions of the form "can I use a different DNSKEY for signing the Questions of the form "can I use a different DNSKEY for signing this
X" have occasionally arisen. RRset" have occasionally arisen.
The short answer is "yes, absolutely". You can even use a different The short answer is "yes, absolutely". You can even use a different
DNSKEY for each RRset in a zone, subject only to practical limits on DNSKEY for each RRset in a zone, subject only to practical limits on
the size of the DNSKEY RRset. However, be aware that there is no way the size of the DNSKEY RRset. However, be aware that there is no way
to tell resolvers what a particularly DNSKEY is supposed to be used to tell resolvers what a particularly DNSKEY is supposed to be used
for -- any DNSKEY in the zone's signed DNSKEY RRset may be used to for -- any DNSKEY in the zone's signed DNSKEY RRset may be used to
authenticate any RRset in the zone. For example, if a weaker or less authenticate any RRset in the zone. For example, if a weaker or less
trusted DNSKEY is being used to authenticate NSEC RRsets or all trusted DNSKEY is being used to authenticate NSEC RRsets or all
dynamically updated records, that same DNSKEY can also be used to dynamically updated records, that same DNSKEY can also be used to
sign any other RRsets from the zone. sign any other RRsets from the zone.
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7.2. Informative References 7.2. Informative References
[I-D.ietf-dnsext-dnssec-experiments] [I-D.ietf-dnsext-dnssec-experiments]
Blacka, D., "DNSSEC Experiments", Blacka, D., "DNSSEC Experiments",
draft-ietf-dnsext-dnssec-experiments-03 (work in draft-ietf-dnsext-dnssec-experiments-03 (work in
progress), April 2006. progress), April 2006.
[I-D.ietf-dnsext-nsec3] [I-D.ietf-dnsext-nsec3]
Laurie, B., "DNSSEC Hashed Authenticated Denial of Laurie, B., "DNSSEC Hashed Authenticated Denial of
Existence", draft-ietf-dnsext-nsec3-07 (work in progress), Existence", draft-ietf-dnsext-nsec3-09 (work in progress),
August 2006. January 2007.
[RFC3597] Gustafsson, A., "Handling of Unknown DNS Resource Record [RFC3597] Gustafsson, A., "Handling of Unknown DNS Resource Record
(RR) Types", RFC 3597, September 2003. (RR) Types", RFC 3597, September 2003.
[RFC4470] Weiler, S. and J. Ihren, "Minimally Covering NSEC Records [RFC4470] Weiler, S. and J. Ihren, "Minimally Covering NSEC Records
and DNSSEC On-line Signing", RFC 4470, April 2006. and DNSSEC On-line Signing", RFC 4470, April 2006.
[RFC4641] Kolkman, O. and R. Gieben, "DNSSEC Operational Practices", [RFC4641] Kolkman, O. and R. Gieben, "DNSSEC Operational Practices",
RFC 4641, September 2006. RFC 4641, September 2006.
Appendix A. Acknowledgments Appendix A. Acknowledgments
The editors are extremely grateful to those who, in addition to The editors are extremely grateful to those who, in addition to
finding errors and omissions in the DNSSECbis document set, have finding errors and omissions in the DNSSECbis document set, have
provided text suitable for inclusion in this document. provided text suitable for inclusion in this document.
The lack of specificity about handling private algorithms, as The lack of specificity about handling private algorithms, as
described in Section 3.2, and the lack of specificity in handling ANY described in Section 3.2, and the lack of specificity in handling ANY
queries, as described in Section 2.3, were discovered by David queries, as described in Section 2.2, were discovered by David
Blacka. Blacka.
The error in algorithm 1 key tag calculation, as described in The error in algorithm 1 key tag calculation, as described in
Section 3.4, was found by Abhijit Hayatnagarkar. Donald Eastlake Section 3.4, was found by Abhijit Hayatnagarkar. Donald Eastlake
contributed text for Section 3.4. contributed text for Section 3.4.
The bug relating to delegation NSEC RR's in Section 2.1 was found by The bug relating to delegation NSEC RR's in Section 2.1 was found by
Roy Badami. Roy Arends found the related problem with DNAME. Roy Badami. Roy Arends found the related problem with DNAME.
The errors in the [RFC4035] examples were found by Roy Arends, who The errors in the [RFC4035] examples were found by Roy Arends, who
also contributed text for Section 4.3 of this document. also contributed text for Section 4.3 of this document.
The editors would like to thank Danny Mayer, Olafur Gudmundsson, and The editors would like to thank Ed Lewis, Danny Mayer, Olafur
Scott Rose for their substantive comments on the text of this Gudmundsson, and Scott Rose for their substantive comments on the
document. text of this document.
Authors' Addresses Authors' Addresses
Samuel Weiler Samuel Weiler
SPARTA, Inc SPARTA, Inc
7110 Samuel Morse Drive 7110 Samuel Morse Drive
Columbia, Maryland 21046 Columbia, Maryland 21046
US US
Email: weiler@tislabs.com Email: weiler@tislabs.com
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Rob Austein Rob Austein
ISC ISC
950 Charter Street 950 Charter Street
Redwood City, CA 94063 Redwood City, CA 94063
USA USA
Email: sra@isc.org Email: sra@isc.org
Full Copyright Statement Full Copyright Statement
Copyright (C) The Internet Society (2006). Copyright (C) The IETF Trust (2007).
This document is subject to the rights, licenses and restrictions This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors contained in BCP 78, and except as set forth therein, the authors
retain all their rights. retain all their rights.
This document and the information contained herein are provided on an This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Intellectual Property Intellectual Property
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights this document or the extent to which any license under such rights
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