diff options
Diffstat (limited to 'contrib/bind9/doc/draft/draft-ietf-dnsext-dnssec-bis-updates-01.txt')
| -rw-r--r-- | contrib/bind9/doc/draft/draft-ietf-dnsext-dnssec-bis-updates-01.txt | 616 |
1 files changed, 0 insertions, 616 deletions
diff --git a/contrib/bind9/doc/draft/draft-ietf-dnsext-dnssec-bis-updates-01.txt b/contrib/bind9/doc/draft/draft-ietf-dnsext-dnssec-bis-updates-01.txt deleted file mode 100644 index 3a800f9..0000000 --- a/contrib/bind9/doc/draft/draft-ietf-dnsext-dnssec-bis-updates-01.txt +++ /dev/null @@ -1,616 +0,0 @@ - - - -Network Working Group S. Weiler -Internet-Draft SPARTA, Inc -Updates: 4034, 4035 (if approved) May 23, 2005 -Expires: November 24, 2005 - - - Clarifications and Implementation Notes for DNSSECbis - draft-ietf-dnsext-dnssec-bis-updates-01 - -Status of this Memo - - By submitting this Internet-Draft, each author represents that any - applicable patent or other IPR claims of which he or she is aware - have been or will be disclosed, and any of which he or she becomes - aware will be disclosed, in accordance with Section 6 of BCP 79. - - Internet-Drafts are working documents of the Internet Engineering - Task Force (IETF), its areas, and its working groups. Note that - other groups may also distribute working documents as Internet- - Drafts. - - 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." - - The list of current Internet-Drafts can be accessed at - http://www.ietf.org/ietf/1id-abstracts.txt. - - The list of Internet-Draft Shadow Directories can be accessed at - http://www.ietf.org/shadow.html. - - This Internet-Draft will expire on November 24, 2005. - -Copyright Notice - - Copyright (C) The Internet Society (2005). - -Abstract - - This document is a collection of minor technical clarifications to - the DNSSECbis document set. It is meant to serve as a resource to - implementors as well as an interim repository of possible DNSSECbis - errata. - - - - - - - -Weiler Expires November 24, 2005 [Page 1] - -Internet-Draft DNSSECbis Implementation Notes May 2005 - - -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 NSEC3 and Epsilon. This document would not make those - changes, merely provide an index into the documents that are making - changes. - -Changes between -00 and -01 - - Document significantly restructured. - - Added section on QTYPE=ANY. - -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. - - - - - - - - - - - - - - - - - - - - - - - - - - -Weiler Expires November 24, 2005 [Page 2] - -Internet-Draft DNSSECbis Implementation Notes May 2005 - - -Table of Contents - - 1. Introduction and Terminology . . . . . . . . . . . . . . . . . 4 - 1.1 Structure of this Document . . . . . . . . . . . . . . . . 4 - 1.2 Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 - 2. Significant Concerns . . . . . . . . . . . . . . . . . . . . . 4 - 2.1 Clarifications on Non-Existence Proofs . . . . . . . . . . 4 - 2.2 Empty Non-Terminal Proofs . . . . . . . . . . . . . . . . 5 - 2.3 Validating Responses to an ANY Query . . . . . . . . . . . 5 - 3. Interoperability Concerns . . . . . . . . . . . . . . . . . . 5 - 3.1 Unknown DS Message Digest Algorithms . . . . . . . . . . . 5 - 3.2 Private Algorithms . . . . . . . . . . . . . . . . . . . . 6 - 3.3 Caution About Local Policy and Multiple RRSIGs . . . . . . 6 - 3.4 Key Tag Calculation . . . . . . . . . . . . . . . . . . . 7 - 4. Minor Corrections and Clarifications . . . . . . . . . . . . . 7 - 4.1 Finding Zone Cuts . . . . . . . . . . . . . . . . . . . . 7 - 4.2 Clarifications on DNSKEY Usage . . . . . . . . . . . . . . 7 - 4.3 Errors in Examples . . . . . . . . . . . . . . . . . . . . 8 - 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 - 6. Security Considerations . . . . . . . . . . . . . . . . . . . 8 - 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8 - 7.1 Normative References . . . . . . . . . . . . . . . . . . . 8 - 7.2 Informative References . . . . . . . . . . . . . . . . . . 9 - Author's Address . . . . . . . . . . . . . . . . . . . . . . . 9 - A. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9 - Intellectual Property and Copyright Statements . . . . . . . . 11 - - - - - - - - - - - - - - - - - - - - - - - - - -Weiler Expires November 24, 2005 [Page 3] - -Internet-Draft DNSSECbis Implementation Notes May 2005 - - -1. Introduction and Terminology - - This document lists some minor clarifications and corrections to - DNSSECbis, as described in [1], [2], and [3]. - - It is intended to serve as a resource for implementors and as a - repository of items that need to be addressed when advancing the - 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 - namedroppers mailing list as well as to the editor of this document. - The editor would greatly prefer text suitable for direct inclusion in - this document. - -1.1 Structure of this Document - - The clarifications to DNSSECbis are sorted according to the editor's - impression of their importance, starting with ones which could, if - ignored, lead to security and stability problems and progressing down - 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 - - The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", - "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this - document are to be interpreted as described in RFC 2119 [4]. - -2. Significant Concerns - - This section provides clarifications that, if overlooked, could lead - to security issues or major interoperability problems. - -2.1 Clarifications on Non-Existence Proofs - - RFC4035 Section 5.4 slightly underspecifies the algorithm for - checking non-existence proofs. In particular, the algorithm there - might incorrectly allow the NSEC from the parent side of a zone cut - to prove the non-existence of either other RRs at that name in the - child zone or other names in the child zone. It might also allow a - NSEC at the same name as a DNAME to prove the non-existence of names - beneath that DNAME. - - - - -Weiler Expires November 24, 2005 [Page 4] - -Internet-Draft DNSSECbis Implementation Notes May 2005 - - - A parent-side delegation NSEC (one with the NS bit set, but no SOA - bit set, and with a singer field that's shorter than the owner name) - must not be used to assume non-existence of any RRs below that zone - cut (both RRs at that ownername and at ownernames with more leading - labels, no matter their content). Similarly, an NSEC with the DNAME - bit set must not be used to assume the non-existence of any - descendant of that NSEC's owner name. - -2.2 Empty Non-Terminal Proofs - - To be written, based on Roy Arends' May 11th message to namedroppers. - -2.3 Validating Responses to an ANY Query - - RFC4035 does not address now to validate responses when QTYPE=*. 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 not - necessary to include all RRsets at the QNAME in the response. - - When validating a response to QTYPE=*, validate all received RRsets - 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 - QCLASS, validate that fact using the rules in RFC4035 Section 5.4 (as - clarified in this document). To be clear, a validator must not - insist on receiving all records at the QNAME in response to QTYPE=*. - -3. Interoperability Concerns - -3.1 Unknown DS Message Digest Algorithms - - Section 5.2 of RFC4035 includes rules for how to handle delegations - to zones that are signed with entirely unsupported algorithms, as - indicated by the algorithms shown in those zone's DS RRsets. It does - not explicitly address how to handle DS records that use unsupported - message digest algorithms. In brief, DS records using unknown or - unsupported message digest algorithms MUST be treated the same way as - DS records referring to DNSKEY RRs of unknown or unsupported - algorithms. - - The existing text says: - - If the validator does not support any of the algorithms listed - in an authenticated DS RRset, then the resolver has no supported - authentication path leading from the parent to the child. The - resolver should treat this case as it would the case of an - authenticated NSEC RRset proving that no DS RRset exists, as - described above. - - - - -Weiler Expires November 24, 2005 [Page 5] - -Internet-Draft DNSSECbis Implementation Notes May 2005 - - - To paraphrase the above, when determining the security status of a - zone, a validator discards (for this purpose only) any DS records - listing unknown or unsupported algorithms. If none are left, the - zone is treated as if it were unsigned. - - Modified to consider DS message digest algorithms, a validator also - discards any DS records using unknown or unsupported message digest - algorithms. - -3.2 Private Algorithms - - As discussed above, section 5.2 of RFC4035 requires that validators - make decisions about the security status of zones based on the public - key algorithms shown in the DS records for those zones. In the case - of private algorithms, as described in RFC4034 Appendix A.1.1, the - eight-bit algorithm field in the DS RR is not conclusive about what - algorithm(s) is actually in use. - - If no private algorithms appear in the DS set or if any supported - algorithm appears in the DS set, no special processing will be - needed. In the remaining cases, the security status of the zone - depends on whether or not the resolver supports any of the private - algorithms in use (provided that these DS records use supported hash - functions, as discussed in Section 3.1). In these cases, the - resolver MUST retrieve the corresponding DNSKEY for each private - algorithm DS record and examine the public key field to determine the - algorithm in use. The security-aware resolver MUST ensure that the - hash of the DNSKEY RR's owner name and RDATA matches the digest in - the DS RR. If they do not match, and no other DS establishes that - the zone is secure, the referral should be considered BAD data, as - discussed in RFC4035. - - This clarification facilitates the broader use of private algorithms, - as suggested by [5]. - -3.3 Caution About Local Policy and Multiple RRSIGs - - When multiple RRSIGs cover a given RRset, RFC4035 Section 5.3.3 - suggests that "the local resolver security policy determines whether - the resolver also has to test these RRSIG RRs and how to resolve - conflicts if these RRSIG RRs lead to differing results." In most - cases, a resolver would be well advised to accept any valid RRSIG as - sufficient. If the first RRSIG tested fails validation, a resolver - would be well advised to try others, giving a successful validation - result if any can be validated and giving a failure only if all - RRSIGs fail validation. - - If a resolver adopts a more restrictive policy, there's a danger that - - - -Weiler Expires November 24, 2005 [Page 6] - -Internet-Draft DNSSECbis Implementation Notes May 2005 - - - properly-signed data might unnecessarily fail validation, perhaps - because of cache timing issues. Furthermore, certain zone management - techniques, like the Double Signature Zone-signing Key Rollover - method described in section 4.2.1.2 of [6] might not work reliably. - -3.4 Key Tag Calculation - - RFC4034 Appendix B.1 incorrectly defines the Key Tag field - calculation for algorithm 1. It correctly says that the Key Tag is - the most significant 16 of the least significant 24 bits of the - public key modulus. However, RFC4034 then goes on to incorrectly say - that this is 4th to last and 3rd to last octets of the public key - modulus. It is, in fact, the 3rd to last and 2nd to last octets. - -4. Minor Corrections and Clarifications - -4.1 Finding Zone Cuts - - 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 - special rules to discover what those servers are. - - 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, - 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 - does not already have the parent's NS RRset. Section 4.2 of RFC4035 - specifies a mechanism for doing that. - -4.2 Clarifications on DNSKEY Usage - - Questions of the form "can I use a different DNSKEY for signing the - X" have occasionally arisen. - - 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 - 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 - 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 - trusted DNSKEY is being used to authenticate NSEC RRsets or all - dynamically updated records, that same DNSKEY can also be used to - sign any other RRsets from the zone. - - Furthermore, note that the SEP bit setting has no effect on how a - DNSKEY may be used -- the validation process is specifically - prohibited from using that bit by RFC4034 section 2.1.2. It possible - to use a DNSKEY without the SEP bit set as the sole secure entry - - - -Weiler Expires November 24, 2005 [Page 7] - -Internet-Draft DNSSECbis Implementation Notes May 2005 - - - point to the zone, yet use a DNSKEY with the SEP bit set to sign all - RRsets in the zone (other than the DNSKEY RRset). It's also possible - to use a single DNSKEY, with or without the SEP bit set, to sign the - entire zone, including the DNSKEY RRset itself. - -4.3 Errors in Examples - - The text in RFC4035 Section C.1 refers to the examples in B.1 as - "x.w.example.com" while B.1 uses "x.w.example". This is painfully - obvious in the second paragraph where it states that the RRSIG labels - field value of 3 indicates that the answer was not the result of - wildcard expansion. This is true for "x.w.example" but not for - "x.w.example.com", which of course has a label count of 4 - (antithetically, a label count of 3 would imply the answer was the - result of a wildcard expansion). - - The first paragraph of RFC4035 Section C.6 also has a minor error: - the reference to "a.z.w.w.example" should instead be "a.z.w.example", - as in the previous line. - -5. IANA Considerations - - This document specifies no IANA Actions. - -6. Security Considerations - - This document does not make fundamental changes to the DNSSEC - protocol, as it was generally understood when DNSSECbis was - published. It does, however, address some ambiguities and omissions - in those documents that, if not recognized and addressed in - implementations, could lead to security failures. In particular, the - validation algorithm clarifications in Section 2 are critical for - preserving the security properties DNSSEC offers. Furthermore, - failure to address some of the interoperability concerns in Section 3 - could limit the ability to later change or expand DNSSEC, including - by adding new algorithms. - -7. References - -7.1 Normative References - - [1] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, - "DNS Security Introduction and Requirements", RFC 4033, - March 2005. - - [2] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, - "Resource Records for the DNS Security Extensions", RFC 4034, - March 2005. - - - -Weiler Expires November 24, 2005 [Page 8] - -Internet-Draft DNSSECbis Implementation Notes May 2005 - - - [3] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, - "Protocol Modifications for the DNS Security Extensions", - RFC 4035, March 2005. - - [4] Bradner, S., "Key words for use in RFCs to Indicate Requirement - Levels", BCP 14, RFC 2119, March 1997. - -7.2 Informative References - - [5] Blacka, D., "DNSSEC Experiments", - draft-blacka-dnssec-experiments-00 (work in progress), - December 2004. - - [6] Gieben, R. and O. Kolkman, "DNSSEC Operational Practices", - draft-ietf-dnsop-dnssec-operational-practices-04 (work in - progress), May 2005. - - -Author's Address - - Samuel Weiler - SPARTA, Inc - 7075 Samuel Morse Drive - Columbia, Maryland 21046 - US - - Email: weiler@tislabs.com - -Appendix A. Acknowledgments - - The editor is extremely grateful to those who, in addition to finding - errors and omissions in the DNSSECbis document set, have provided - text suitable for inclusion in this document. - - The lack of specificity about handling private algorithms, as - described in Section 3.2, and the lack of specificity in handling ANY - queries, as described in Section 2.3, were discovered by David - Blacka. - - The error in algorithm 1 key tag calculation, as described in - Section 3.4, was found by Abhijit Hayatnagarkar. Donald Eastlake - contributed text for Section 3.4. - - 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. - - The errors in the RFC4035 examples were found by Roy Arends, who also - contributed text for Section 4.3 of this document. - - - -Weiler Expires November 24, 2005 [Page 9] - -Internet-Draft DNSSECbis Implementation Notes May 2005 - - - The editor would like to thank Olafur Gudmundsson and Scott Rose for - their substantive comments on the text of this document. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -Weiler Expires November 24, 2005 [Page 10] - -Internet-Draft DNSSECbis Implementation Notes May 2005 - - -Intellectual Property Statement - - The IETF takes no position regarding the validity or scope of any - Intellectual Property Rights or other rights that might be claimed to - pertain to the implementation or use of the technology described in - this document or the extent to which any license under such rights - might or might not be available; nor does it represent that it has - made any independent effort to identify any such rights. Information - on the procedures with respect to rights in RFC documents can be - found in BCP 78 and BCP 79. - - Copies of IPR disclosures made to the IETF Secretariat and any - assurances of licenses to be made available, or the result of an - attempt made to obtain a general license or permission for the use of - such proprietary rights by implementers or users of this - specification can be obtained from the IETF on-line IPR repository at - http://www.ietf.org/ipr. - - The IETF invites any interested party to bring to its attention any - copyrights, patents or patent applications, or other proprietary - rights that may cover technology that may be required to implement - this standard. Please address the information to the IETF at - ietf-ipr@ietf.org. - - -Disclaimer of Validity - - This document and the information contained herein are provided on an - "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS - OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET - ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, - INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE - INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED - WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. - - -Copyright Statement - - Copyright (C) The Internet Society (2005). This document is subject - to the rights, licenses and restrictions contained in BCP 78, and - except as set forth therein, the authors retain all their rights. - - -Acknowledgment - - Funding for the RFC Editor function is currently provided by the - Internet Society. - - - - -Weiler Expires November 24, 2005 [Page 11] - |
