Internet DRAFT - draft-tbruijnzeels-sidrops-signed-tal
draft-tbruijnzeels-sidrops-signed-tal
Network Working Group T. Bruijnzeels
Internet-Draft RIPE NCC
Intended status: Standards Track C. Martinez
Expires: February 16, 2018 LACNIC
August 15, 2017
RPKI signed object for TAL
draft-tbruijnzeels-sidrops-signed-tal-01
Abstract
Trust Anchor Locators (TALs) [RFC7730] are used by Relying Parties in
the RPKI to locate and validate Trust Anchor certificates used in
RPKI validation. This document defines an RPKI signed object
[RFC6488] for a Trust Anchor Locator (TAL) that can be published by
Trust Anchor to communicate a new TAL to already deployed Relying
Parties. The two primary use cases for this are that 1) a Trust
Anchor may wish to change the locations where its TA certificate may
be found, and 2) a Trust Anchor may wish to perform a planned
migration to a new key. Note that unplanned key rolls are considered
out of scope for this document.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on February 16, 2018.
Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
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Table of Contents
1. Requirements notation . . . . . . . . . . . . . . . . . . . . 2
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Signed TAL definition . . . . . . . . . . . . . . . . . . . . 3
3.1. The Signed TAL Content Type . . . . . . . . . . . . . . . 4
3.2. The Signed TAL eContent . . . . . . . . . . . . . . . . . 4
3.3. Signed TAL Validation . . . . . . . . . . . . . . . . . . 4
4. Signed TAL Generation . . . . . . . . . . . . . . . . . . . . 4
5. Signed TAL Publication . . . . . . . . . . . . . . . . . . . 5
6. Supporting a TA Key Roll . . . . . . . . . . . . . . . . . . 5
6.1. Preparing a new TA key . . . . . . . . . . . . . . . . . 6
6.2. Staging period - Using both the old and the new TA key . 6
6.3. Preserving the Signed TAL . . . . . . . . . . . . . . . . 6
6.4. Retiring the old key . . . . . . . . . . . . . . . . . . 7
6.5. Relying Party Use . . . . . . . . . . . . . . . . . . . . 7
7. Supporting changing TA certificate publication point(s) . . . 7
7.1. Adding a publication point . . . . . . . . . . . . . . . 7
7.2. Withdrawing a publication point . . . . . . . . . . . . . 7
7.3. Publishing the Signed TAL . . . . . . . . . . . . . . . . 7
7.4. Relying Party Use . . . . . . . . . . . . . . . . . . . . 7
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
8.1. OID . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
8.2. File Extension . . . . . . . . . . . . . . . . . . . . . 8
9. Security Considerations . . . . . . . . . . . . . . . . . . . 8
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
11.1. Normative References . . . . . . . . . . . . . . . . . . 8
11.2. Informative References . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Requirements notation
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 [RFC2119].
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2. Introduction
Trust Anchor Locator (TAL) files [RFC7730] are used in the Resource
Public Key Infrastructure (RPKI) to help Relying Parties locate and
verify a trust anchor certificate. A TAL file consists of:
o One or more rsync URIs [RFC5781]
o A subjectPublicKeyInfo [RFC5280] in DER format [X.509], encoded in
Base64
The TAL can be distributed out-of-band to Relying Parties (RP), and
it allows the RP to retrieve the most recent version of the Trust
Anchor (TA) certificate from the cited location, and verify that
public key of this certificate matches the TAL. This is useful as it
allows selected data in the trust anchor to change, without needing
to effect redistribution of the trust anchor per se. In particular
the Internet Number Resources (INRs) extension [RFC3779] and the
publication points defined in the Subject Information Access
[RFC6487] may be updated this way.
The assumption is that both the URIs and key of the TA certificate
remain stable. However, an organisation operating a TA may wish to
change either of these properties, because of a need to:
o change one or more URIs
o perform a planned key roll
In this document we describe a method for TA operators to publish a
an updated TAL in a secure a well-defined fashion, so that RPs can be
alerted about these changes.
Note that [RFC5011] describes Automated Updates of DNS Security
(DNSSEC) Trust Anchors and can provide some useful insight here as
well. However, concepts like a set of Trust Anchors, standby Trust
Anchors, and TTLs are not applicable to the RPKI. Therefore we
believe that an alternative approach based on already existing
concept of the Trust Anchor Locator [RFC7730] is appropriate.
3. Signed TAL definition
A signed TAL is an RPKI signed object, as specified in [RFC6488].
The RPKI signed object template requires specification of the
following data elements in the context of the manifest structure.
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3.1. The Signed TAL Content Type
This document requests an OID for signed-Tal as follows:
signed-Tal OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840)
rsadsi(113549) pkcs(1) pkcs9(9) 16 id-smime (1) TBD }
This OID MUST appear both within the eContentType in the
encapContentInfo object as well as the content-type signed attribute
in the signerInfo object (see [RFC6488]).
3.2. The Signed TAL eContent
The content of a Signed TAL is ASN.1 encoded using the Distinguished
Encoding Rules (DER) [X.690], and is defined as follows:
SignedTalContent ::= IA5String
The "SignedTalContent" contains the content of the new TAL encoded in
Base64 [RFC4648].
3.3. Signed TAL Validation
Before a Relying Party can use a Signed TAL, the relying party MUST
first validate the Signed TAL. To validate a Signed TAL, the relying
party MUST perform all the validation checks specified in [RFC6488]
as well as the following additional specific validation step.
o The eContentType in the EncapsulatedContentInfo has OID
1.2.840.113549.1.9.16.1.TBD.
o The EE certificate of this Signed TAL is signed by a known Trust
Anchor
o The decoded TAL content conforms to the format defined in
[RFC7730]
If the above procedure indicates that the manifest is invalid, then
the Signed TAL MUST be discarded and treated as though no Signed TAL
were present.
4. Signed TAL Generation
A TA MAY choose to generate a single Singed TAL object to publish in
its TA certificate publication point(s) in the RPKI. The TA MUST
perform the following steps to generate the Signed TAL:
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o Generate a key pair for a "one-time-use" EE certificate to use for
the Signed TAL
o Generate a one-time-use EE certificate for the Signed TAL
o This EE certificate MUST have an SIA extension access description
field with an accessMethod OID value of id-ad-signedobject, where
the associated accessLocation references the publication point of
the Sigend TAL as an object URL.
o As described in [RFC6487], an [RFC3779] extension is required in
the EE certificate used for this object. However, because the
resource set is irrelevant to this object type, this certificate
MUST describe its Internet Number Resources (INRs) using the
"inherit" attribute, rather than explicit description of a
resource set.
o This EE certificate MUST have a "notBefore" time that is before
the moment that the Signed TAL will be published.
o This EE certificate MUST have a "notAfter" time that reflects the
intended time that this Signed TAL will be published. If the EE
certificate for a Signed TAL is expired, it MUST no longer be
publish, but of course it MAY be replaced by a newly generated
Signed TAL object with similar content and an updated "notAfter"
time.
5. Signed TAL Publication
A TA MAY publish a single Signed TAL object directly under its CA
repository publication points. A non-normative guideline for naming
this object is that the filename chosen for the signed TAL in the
publication repository be a value derived from the public key part of
the entity's key pair, using the algorithm described for CRLs in
section 2.2 of [RFC6481] for generation of filenames. The filename
extension of ".tal" MUST be used to denote the object as a signed
TAL. Note that this is in-line with filename extensions defined in
section 7.2 of [RFC6481].
6. Supporting a TA Key Roll
A Signed TAL MAY be used to communicate a planned key roll for the
TA.
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6.1. Preparing a new TA key
Prior to publishing the Signed TAL for the new key the TA MUST
perform the following steps:
o Generate a new key pair for the new TA certificate
o Generate a new TA Certificate, using a Subject Information Access
for CA certificates (see section 4.8.8.1 of [RFC6487]) that
references the URIs that will be used by the new key to publish
objects, that are different from the URIs used by the TA
certificate for the current key.
o ALL current signed certificates and other objects, with the
exception of the old CRL, Manifest and Signed TAL, must be re-
issued by the new key and published under the new publication
point(s).
o The new TA certificate itself MUST be published in a (number of)
new location(s) that are different from where the TA certificate
for the current key is published.
After these steps are performed a new Signed TAL MUST be generated as
described in Section 4, and published as described in Section 5.
6.2. Staging period - Using both the old and the new TA key
The staging period is initiated by the initial publication of a
Signed TAL for the new key and must be last at least 24 HOURS.
During the staging period the TA MUST continue to operate both the
old and the new TA key. Note that this is the same staging period
used for key roll of normal CAs in the RPKI, described in [RFC6489].
6.3. Preserving the Signed TAL
The TA SHOULD preserve a Signed TAL for the old key after the staging
period as a hint for RPs that missed the key roll. The following
process can be used to achieve this:
o Produce a new long-lived CRL that revokes all previously signed
certificates
o Produce a new long-lived Signed TAL
o Produce a new long-lived manifest that includes the CRL and Signed
TAL
o Publish the CRL, MFT and Signed TAL
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o Destroy the old TA key
6.4. Retiring the old key
The TA SHOULD retire and delete its old key after the staging period
is over.
6.5. Relying Party Use
When an RP discovers a valid Signed TAL signed under a TA, and it
notices that the contained TAL is different from its current TAL for
this TA and that the "subjectPublicKeyInfo" has changed, then the RP
MUST replace the TAL for this TA with the new TAL, abort the current
top-down validation operation, and initiate a new top-down validation
operation using the updated TAL.
It is RECOMMENDED that the software informs the operator of this
event.
7. Supporting changing TA certificate publication point(s)
A signed TAL MAY be used to communicate an addition or removal of one
or more publication locations where the TA certificate can be found.
7.1. Adding a publication point
When adding a publication point for a TA certificate, the TA MUST
publish the certificate in the new location(s) prior to publication
of the Signed TAL.
7.2. Withdrawing a publication point
When removing a publication point for TA certificate, the TA SHOULD
observe a staging period of at least 24 Hours. The staging period is
initiated by the publication of an updated Signed TAL where the
publication point has been removed. During the staging period the TA
SHOULD keep the old publication point up to date and available.
7.3. Publishing the Signed TAL
It is RECOMMENDED that a Trust Anchor publishes a valid Signed TAL
for what it believes its current TAL should be at all times.
7.4. Relying Party Use
When an RP discovers a valid Signed TAL signed under a TA, and it
notices that the contained TAL is different from its current TAL for
this TA and that the "subjectPublicKeyInfo" has not changed, then the
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RP MUST replace the TAL for this TA with the new TAL for future use,
but can continue the current top-down validation operation.
It is RECOMMENDED that the software informs the operator of this
event.
8. IANA Considerations
8.1. OID
IANA is to add the following to the "RPKI Signed Objects" registry:
Decimal Description References
TBD signed-Tal [section 3.1]
8.2. File Extension
IANA is to add an item for the Signed TAL file extension to the "RPKI
Repository Name Scheme" created by [RFC6481] as follows:
Extension RPKI Object Reference
-------------------------------------------------------
.tal Signed TAL [this document]
9. Security Considerations
TBD
10. Acknowledgements
TBD
11. References
11.1. 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,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC3779] Lynn, C., Kent, S., and K. Seo, "X.509 Extensions for IP
Addresses and AS Identifiers", RFC 3779,
DOI 10.17487/RFC3779, June 2004,
<http://www.rfc-editor.org/info/rfc3779>.
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[RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data
Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006,
<http://www.rfc-editor.org/info/rfc4648>.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
<http://www.rfc-editor.org/info/rfc5280>.
[RFC5781] Weiler, S., Ward, D., and R. Housley, "The rsync URI
Scheme", RFC 5781, DOI 10.17487/RFC5781, February 2010,
<http://www.rfc-editor.org/info/rfc5781>.
[RFC6481] Huston, G., Loomans, R., and G. Michaelson, "A Profile for
Resource Certificate Repository Structure", RFC 6481,
DOI 10.17487/RFC6481, February 2012,
<http://www.rfc-editor.org/info/rfc6481>.
[RFC6487] Huston, G., Michaelson, G., and R. Loomans, "A Profile for
X.509 PKIX Resource Certificates", RFC 6487,
DOI 10.17487/RFC6487, February 2012,
<http://www.rfc-editor.org/info/rfc6487>.
[RFC6488] Lepinski, M., Chi, A., and S. Kent, "Signed Object
Template for the Resource Public Key Infrastructure
(RPKI)", RFC 6488, DOI 10.17487/RFC6488, February 2012,
<http://www.rfc-editor.org/info/rfc6488>.
[RFC7730] Huston, G., Weiler, S., Michaelson, G., and S. Kent,
"Resource Public Key Infrastructure (RPKI) Trust Anchor
Locator", RFC 7730, DOI 10.17487/RFC7730, January 2016,
<http://www.rfc-editor.org/info/rfc7730>.
[X.509] ITU-T Recommendation X.509 (2000), "Recommendation X.509:
The Directory - Authentication Framework", 2000.
[X.690] ITU-T Recommendation X.690 (2002) | ISO/IEC 8825-1:2002,
"Information technology - ASN.1 encoding rules:
Specification of Basic Encoding Rules (BER), Canonical
Encoding Rules (CER) and Distinguished Encoding Rules
(DER)", 2002.
11.2. Informative References
[RFC5011] StJohns, M., "Automated Updates of DNS Security (DNSSEC)
Trust Anchors", STD 74, RFC 5011, DOI 10.17487/RFC5011,
September 2007, <http://www.rfc-editor.org/info/rfc5011>.
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[RFC6489] Huston, G., Michaelson, G., and S. Kent, "Certification
Authority (CA) Key Rollover in the Resource Public Key
Infrastructure (RPKI)", BCP 174, RFC 6489,
DOI 10.17487/RFC6489, February 2012,
<http://www.rfc-editor.org/info/rfc6489>.
Authors' Addresses
Tim Bruijnzeels
RIPE NCC
Email: tim@ripe.net
Carlos Martinez
LACNIC
Email: carlos@lacnic.net
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