Subject: [dnsext] [Technical Errata Reported] RFC5155 (3441)

From: RFC Errata System <[email-masked]>
Date: Mon, 31 Dec 2012 07:51:10 -0800 (PST)

The following errata report has been submitted for RFC5155,
"DNS Security (DNSSEC) Hashed Authenticated Denial of Existence".

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You may review the report below and at:
http://www.rfc-editor.org/errata_search.php?rfc=5155&eid=3441

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Type: Technical
Reported by: Edward Lewis <[email-masked]>

Section: 7.2.3 & 8.5

Original Text
-------------
7.2.3

(contents)

8.5

(contents)

Corrected Text
--------------
7.2.3.  No Data Responses, QTYPE is not DS

  If the No Data Response is a result of an empty non-terminal derived 
  from an insecure delegation covered by an Opt-Out NSEC3 RR, the 
  closest provable encloser proof MUST be included in the response.  
  The included NSEC3 RR that covers the "next closer" name for the 
  delegation MUST have the Opt-Out flag set to one. 

  In all other cases, the server MUST include the NSEC3 RR that matches 
  QNAME.  This NSEC3 RR MUST NOT have the bits corresponding to either 
  the QTYPE or CNAME set in its Type Bit Maps field.

===============================================

8.5.  Validating No Data Responses, QTYPE is not DS

  If there is an NSEC3 RR that matches QNAME present, the validator must 
  check that both the QTYPE and the CNAME type are not set in its Type 
  Bit Maps field.

  Note that this test also covers the case where the NSEC3 RR exists
  because it corresponds to an empty non-terminal, in which case the
  NSEC3 RR will have an empty Type Bit Maps field.

  If there is no NSEC3 RR present that matches QNAME, then the validator 
  MUST verify a closest provable encloser proof for the QNAME.  The 
  validator MUST verify that the Opt-Out bit is set in the NSEC3 RR that 
  covers the "next closer" name to the delegation name. This test covers 
  the case where the response is due to an Empty Non-Terminal derived 
  from an insecure delegation covered by an Opt-Out NSEC3 RR.

Notes
-----
The corrections were derived from a private email from an editor of RFC 5155.  Note that the ordering of the paragraphs in the proposed 8.5 fix has been changed.  No other change is intentional.

>From Roy Arends:

We missed documenting the case of what a server and a validator should do in case of an opted-out, multi-label delegation. We did make it clear in signing (7.1). 

This is also not part of the demo zone, included in RFC5155.

As suggested text for an errata, may I offer:

7.2.3.  No Data Responses, QTYPE is not DS

  If the No Data Response is a result of an empty non-terminal derived 
  from an insecure delegation covered by an Opt-Out NSEC3 RR, the 
  closest provable encloser proof MUST be included in the response.  
  The included NSEC3 RR that covers the "next closer" name for the 
  delegation MUST have the Opt-Out flag set to one. 

  In all other cases, the server MUST include the NSEC3 RR that matches 
  QNAME.  This NSEC3 RR MUST NOT have the bits corresponding to either 
  the QTYPE or CNAME set in its Type Bit Maps field.

8.5.  Validating No Data Responses, QTYPE is not DS

  If there is no NSEC3 RR present that matches QNAME, then the validator 
  MUST verify a closest provable encloser proof for the QNAME.  The 
  validator MUST verify that the Opt-Out bit is set in the NSEC3 RR that 
  covers the "next closer" name to the delegation name. This test covers 
  the case where the response is due to an Empty Non-Terminal derived 
  from an insecure delegation covered by an Opt-Out NSEC3 RR.

  If there is an NSEC3 RR that matches QNAME present, the validator must 
  check that both the QTYPE and the CNAME type are not set in its Type 
  Bit Maps field.

  Note that this test also covers the case where the NSEC3 RR exists
  because it corresponds to an empty non-terminal, in which case the
  NSEC3 RR will have an empty Type Bit Maps field.

The following message is the singularly most important one in the errata submission, from David Blacka, commenting on the order of the paragraphs:

http://www.ietf.org/mail-archive/web/dnsext/current/msg12835.html

The heads of the threads to review:

http://www.ietf.org/mail-archive/web/dnsext/current/msg12819.html
http://www.ietf.org/mail-archive/web/dnsext/current/msg12821.html
http://www.ietf.org/mail-archive/web/dnsext/current/msg12830.html
http://www.ietf.org/mail-archive/web/dnsext/current/msg12832.html
http://www.ietf.org/mail-archive/web/dnsext/current/msg12839.html
http://www.ietf.org/mail-archive/web/dnsext/current/msg12854.html
and
http://www.ietf.org/mail-archive/web/dnsext/current/msg12864.html

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RFC5155 (draft-ietf-dnsext-nsec3-13)
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Title               : DNS Security (DNSSEC) Hashed Authenticated Denial of Existence
Publication Date    : March 2008
Author(s)           : B. Laurie, G. Sisson, R. Arends, D. Blacka
Category            : PROPOSED STANDARD
Source              : DNS Extensions
Area                : Internet
Stream              : IETF
Verifying Party     : IESG