draft-ietf-dnsop-kskroll-sentinel-08.txt   draft-ietf-dnsop-kskroll-sentinel-09.txt 
DNSOP G. Huston DNSOP G. Huston
Internet-Draft J. Damas Internet-Draft J. Damas
Intended status: Standards Track APNIC Intended status: Standards Track APNIC
Expires: September 25, 2018 W. Kumari Expires: September 27, 2018 W. Kumari
Google Google
March 24, 2018 March 26, 2018
A Root Key Trust Anchor Sentinel for DNSSEC A Root Key Trust Anchor Sentinel for DNSSEC
draft-ietf-dnsop-kskroll-sentinel-08 draft-ietf-dnsop-kskroll-sentinel-09
Abstract Abstract
The DNS Security Extensions (DNSSEC) were developed to provide origin The DNS Security Extensions (DNSSEC) were developed to provide origin
authentication and integrity protection for DNS data by using digital authentication and integrity protection for DNS data by using digital
signatures. These digital signatures can be verified by building a signatures. These digital signatures can be verified by building a
chain of trust starting from a trust anchor and proceeding down to a chain of trust starting from a trust anchor and proceeding down to a
particular node in the DNS. This document specifies a mechanism that particular node in the DNS. This document specifies a mechanism that
will allow an end user and third parties to determine the trusted key will allow an end user and third parties to determine the trusted key
state for the root key of the resolvers that handle that user's DNS state for the root key of the resolvers that handle that user's DNS
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There is an example / toy implementation of this at http://www.ksk- There is an example / toy implementation of this at http://www.ksk-
test.net . test.net .
[ This document is being collaborated on in Github at: [ This document is being collaborated on in Github at:
https://github.com/APNIC-Labs/draft-kskroll-sentinel. The most https://github.com/APNIC-Labs/draft-kskroll-sentinel. The most
recent version of the document, open issues, etc should all be recent version of the document, open issues, etc should all be
available here. The authors (gratefully) accept pull requests. Text available here. The authors (gratefully) accept pull requests. Text
in square brackets will be removed before publication. ] in square brackets will be removed before publication. ]
[ NOTE: This version uses the labels "kskroll-sentinel-is-ta-<key- [ NOTE: This version uses the labels "root-key-sentinel-is-ta-", and
tag>", "kskroll-sentinel-not-ta-<key-tag>"; older versions of this "root-key-sentinel-not-ta-".; older versions of this document used
document used "_is-ta-<key-tag>", "_not-ta-<key-tag>". Also note "kskroll-sentinel-is-ta-<key-tag>", "kskroll-sentinel-not-ta-<key-
that the format of the tag-index is now zero-filled decimal. tag>", and before that, "_is-ta-<key-tag>", "_not-ta-<key-tag>".
Apolgies to those who have began implmenting.] Also note that the format of the tag-index is now zero-filled
decimal. Apolgies to those who have began implmenting.]
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 25, 2018. This Internet-Draft will expire on September 27, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2. Protocol Walkthrough Example . . . . . . . . . . . . . . . . 4 2. Protocol Walkthrough Example . . . . . . . . . . . . . . . . 4
3. Sentinel Mechanism in Resolvers . . . . . . . . . . . . . . . 7 3. Sentinel Mechanism in Resolvers . . . . . . . . . . . . . . . 7
3.1. Preconditions . . . . . . . . . . . . . . . . . . . . . . 7 3.1. Preconditions . . . . . . . . . . . . . . . . . . . . . . 7
3.2. Special processing . . . . . . . . . . . . . . . . . . . 8 3.2. Special processing . . . . . . . . . . . . . . . . . . . 8
4. Processing Sentinel Results . . . . . . . . . . . . . . . . . 8 4. Processing Sentinel Results . . . . . . . . . . . . . . . . . 8
5. Sentinel Test Result Considerations . . . . . . . . . . . . . 10 5. Sentinel Test Result Considerations . . . . . . . . . . . . . 10
6. Security Considerations . . . . . . . . . . . . . . . . . . . 11 6. Security Considerations . . . . . . . . . . . . . . . . . . . 11
7. Privacy Considerations . . . . . . . . . . . . . . . . . . . 12 7. Privacy Considerations . . . . . . . . . . . . . . . . . . . 12
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12
10. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 12 10. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 12
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
11.1. Normative References . . . . . . . . . . . . . . . . . . 14 11.1. Normative References . . . . . . . . . . . . . . . . . . 15
11.2. Informative References . . . . . . . . . . . . . . . . . 15 11.2. Informative References . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
1. Introduction 1. Introduction
The DNS Security Extensions (DNSSEC) [RFC4033], [RFC4034] and The DNS Security Extensions (DNSSEC) [RFC4033], [RFC4034] and
[RFC4035] were developed to provide origin authentication and [RFC4035] were developed to provide origin authentication and
integrity protection for DNS data by using digital signatures. integrity protection for DNS data by using digital signatures.
DNSSEC uses Key Tags to efficiently match signatures to the keys from DNSSEC uses Key Tags to efficiently match signatures to the keys from
which they are generated. The Key Tag is a 16-bit value computed which they are generated. The Key Tag is a 16-bit value computed
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KSK indicated by the special names. The protocol uses the DNS KSK indicated by the special names. The protocol uses the DNS
SERVFAIL response code (RCODE 2) for this purpose because that is the SERVFAIL response code (RCODE 2) for this purpose because that is the
response code that is returned by resolvers when DNSSEC validation response code that is returned by resolvers when DNSSEC validation
fails. If a browser or operating system has multiple resolvers fails. If a browser or operating system has multiple resolvers
configured, and those resolvers have different properties (for configured, and those resolvers have different properties (for
example, one performs DNSSEC validation and one does not), the example, one performs DNSSEC validation and one does not), the
sentinel mechanism might search among the different resolvers, or sentinel mechanism might search among the different resolvers, or
might not, depending on how the browser or operating system is might not, depending on how the browser or operating system is
configured. configured.
Note that the sentinel mechanism described here measures a very
different (and likely more useful) metric than [RFC8145]. RFC 8145
relies on resolvers reporting the list of keys that they have to root
servers. That reflects on how many resolvers will be impacted by a
KSK roll, but not what the user impact of the KSK roll will be.
1.1. Terminology 1.1. 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 RFC 2119. document are to be interpreted as described in RFC 2119.
2. Protocol Walkthrough Example 2. Protocol Walkthrough Example
[Ed note: This is currently towards the front of the document; we [Ed note: This is currently towards the front of the document; we
will make it an appendix at publication time, but until then it is will make it an appendix at publication time, but until then it is
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The above description is a simplified example - it is not anticipated The above description is a simplified example - it is not anticipated
that Bob, Charlie, Dave and Ed will actually look for the absence or that Bob, Charlie, Dave and Ed will actually look for the absence or
presence of web resources; instead, the webpage that they load would presence of web resources; instead, the webpage that they load would
likely contain JavaScript (or similar) which displays the result of likely contain JavaScript (or similar) which displays the result of
the tests, sends the results to Geoff, or both. This sentinel the tests, sends the results to Geoff, or both. This sentinel
mechanism does not rely on the web: it can equally be used by trying mechanism does not rely on the web: it can equally be used by trying
to resolve the names (for example, using the common "dig" command) to resolve the names (for example, using the common "dig" command)
and checking which result in a SERVFAIL. and checking which result in a SERVFAIL.
Note that the sentinel mechanism described here measures a very
different (and likely more useful) metric than [RFC8145]. RFC 8145
relies on resolvers reporting the list of keys that they have to root
servers. That reflects on how many resolvers will be impacted by a
KSK roll, but not what the user impact of the KSK roll will be.
3. Sentinel Mechanism in Resolvers 3. Sentinel Mechanism in Resolvers
DNSSEC-Validating resolvers that implement this mechanism MUST DNSSEC-Validating resolvers that implement this mechanism MUST
perform validation of responses in accordance with the DNSSEC perform validation of responses in accordance with the DNSSEC
response validation specification [RFC4035]. response validation specification [RFC4035].
This sentinel mechanism makes use of two special labels: This sentinel mechanism makes use of two special labels:
o root-key-sentinel-is-ta-<key-tag> o root-key-sentinel-is-ta-<key-tag>
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is currently trusting?" Labels containing "root-key-sentinel-not-ta- is currently trusting?" Labels containing "root-key-sentinel-not-ta-
<key-tag>" is used to answer the question "Is this the Key Tag *not* <key-tag>" is used to answer the question "Is this the Key Tag *not*
a trust anchor which the validating DNS resolver is currently a trust anchor which the validating DNS resolver is currently
trusting?" trusting?"
3.1. Preconditions 3.1. Preconditions
All of the following conditions must be met to trigger special All of the following conditions must be met to trigger special
processing inside resolver code: processing inside resolver code:
o The DNS response is DNSSEC validated and result of validation is o The DNS response is DNSSEC validated, regardless of whether
DNSSSEC validation was requested, and result of validation is
"Secure" "Secure"
o The QTYPE is either A or AAAA (Query Type value 1 or 28) o The QTYPE is either A or AAAA (Query Type value 1 or 28)
o The OPCODE is QUERY o The OPCODE is QUERY
o The leftmost label of the QNAME is either "root-key-sentinel-is- o The leftmost label of the original QNAME (the name sent in the
ta-<key-tag>" or "root-key-sentinel-not-ta-<key-tag>" Question Section in the orignal query) is either "root-key-
sentinel-is-ta-<key-tag>" or "root-key-sentinel-not-ta-<key-tag>"
If any one of the preconditions is not met, the resolver MUST NOT If any one of the preconditions is not met, the resolver MUST NOT
alter the DNS response based on the mechanism in this document. alter the DNS response based on the mechanism in this document.
3.2. Special processing 3.2. Special processing
Responses which fullfill all of the preconditions in Section 3.1 Responses which fullfill all of the preconditions in Section 3.1
require special processing, depending on leftmost label in the QNAME. require special processing, depending on leftmost label in the QNAME.
First, the resolver determines if the numerical value of <key-tag> is First, the resolver determines if the numerical value of <key-tag> is
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resolver, identified a number of places where it wasn't clear, and resolver, identified a number of places where it wasn't clear, and
provided very helpful text to address this. provided very helpful text to address this.
10. Change Log 10. Change Log
RFC Editor: Please remove this section! RFC Editor: Please remove this section!
Note that this document is being worked on in GitHub - see Abstract. Note that this document is being worked on in GitHub - see Abstract.
The below is mainly large changes, and is not authoritative. The below is mainly large changes, and is not authoritative.
From -08 to -09:
o Incorporated Paul Hoffman's PR # 15 (Two issues from the
Hackathon) - https://github.com/APNIC-Labs/draft-kskroll-sentinel/
pull/15
o Clarifies that the match is on the *original* QNAME.
From -08 to -07: From -08 to -07:
o Changed title from "A Sentinel for Detecting Trusted Keys in o Changed title from "A Sentinel for Detecting Trusted Keys in
DNSSEC" to "A Root Key Trust Anchor Sentinel for DNSSEC". DNSSEC" to "A Root Key Trust Anchor Sentinel for DNSSEC".
o Changed magic string from "kskroll-sentinel-" to "root-key- o Changed magic string from "kskroll-sentinel-" to "root-key-
sentinel-" -- this time for sure, Rocky! sentinel-" -- this time for sure, Rocky!
From -07 to -06: From -07 to -06:
 End of changes. 12 change blocks. 
20 lines changed or deleted 31 lines changed or added

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