IGP extension for PCEP security capability support in the PCE discovery
draft-ietf-lsr-pce-discovery-security-support-09
| Document | Type | Active Internet-Draft (lsr WG) | |
|---|---|---|---|
| Authors | Diego Lopez , Qin Wu , Dhruv Dhody , Qiufang Ma , Daniel King | ||
| Last updated | 2021-08-21 | ||
| Replaces | draft-wu-lsr-pce-discovery-security-support | ||
| Stream | Internet Engineering Task Force (IETF) | ||
| Intended RFC status | Proposed Standard | ||
| Formats | plain text html xml pdf htmlized bibtex | ||
| Reviews | |||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Acee Lindem | ||
| Shepherd write-up | Show (last changed 2021-08-20) | ||
| IESG | IESG state | Publication Requested | |
| Action Holders |
(None)
|
||
| Consensus Boilerplate | Yes | ||
| Telechat date | |||
| Responsible AD | John Scudder | ||
| Send notices to | Acee Lindem <acee@cisco.com>, pce@ietf.org, lsr@ietf.org | ||
PCE working group D. Lopez
Internet-Draft Telefonica I+D
Updates: 5088, 5089, 8231, 8306, 8623 (if Q. Wu
approved) D. Dhody
Intended status: Standards Track Q. Ma
Expires: 22 February 2022 Huawei
D. King
Old Dog Consulting
21 August 2021
IGP extension for PCEP security capability support in the PCE discovery
draft-ietf-lsr-pce-discovery-security-support-09
Abstract
When a Path Computation Element (PCE) is a Label Switching Router
(LSR) participating in the Interior Gateway Protocol (IGP), or even a
server participating in IGP, its presence and path computation
capabilities can be advertised using IGP flooding. The IGP
extensions for PCE discovery (RFC 5088 and RFC 5089) define a method
to advertise path computation capabilities using IGP flooding for
OSPF and IS-IS respectively. However these specifications lack a
method to advertise PCEP security (e.g., Transport Layer Security
(TLS), TCP Authentication Option (TCP-AO)) support capability.
This document defines capability flag bits for PCE-CAP-FLAGS sub-TLV
that can be announced as an attribute in the IGP advertisement to
distribute PCEP security support information. In addition, this
document updates RFC 5088 and RFC 5089 to allow advertisement of Key
ID or Key Chain Name Sub-TLV to support TCP-AO security capability.
RFC 8231, RFC 8306, and RFC 8623 are also updated to reflect the
movement of the IANA "PCE Capability Flags" registry.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
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."
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This Internet-Draft will expire on 22 February 2022.
Copyright Notice
Copyright (c) 2021 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 (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
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as described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions used in this document . . . . . . . . . . . . . . 3
3. IGP extension for PCEP security capability support . . . . . 3
3.1. Use of PCEP security capability support for PCE
discovery . . . . . . . . . . . . . . . . . . . . . . . . 4
3.2. KEY-ID Sub-TLV . . . . . . . . . . . . . . . . . . . . . 4
3.3. KEY-CHAIN-NAME Sub-TLV . . . . . . . . . . . . . . . . . 5
4. Update to RFC5088 and RFC5089 . . . . . . . . . . . . . . . . 5
5. Backward Compatibility Consideration . . . . . . . . . . . . 6
6. Management Considerations . . . . . . . . . . . . . . . . . . 6
7. Security Considerations . . . . . . . . . . . . . . . . . . . 6
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
8.1. PCE Capability Flag . . . . . . . . . . . . . . . . . . . 7
8.2. PCED sub-TLV Type Indicators . . . . . . . . . . . . . . 7
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 7
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
10.1. Normative References . . . . . . . . . . . . . . . . . . 8
10.2. Informative References . . . . . . . . . . . . . . . . . 9
Appendix A. No MD5 Capability Support . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction
As described in [RFC5440], PCEP communication privacy is one
importance issue, as an attacker that intercepts a Path Computation
Element (PCE) message could obtain sensitive information related to
computed paths and resources.
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Among the possible solutions mentioned in these documents, Transport
Layer Security (TLS) [RFC8446] provides support for peer
authentication, and message encryption and integrity while TCP
Authentication Option (TCP-AO) [RFC5925] and Cryptographic Algorithms
for TCP-AO [RFC5926] offer significantly improved security for
applications using TCP. As specified in section 4 of [RFC8253], in
order for a Path Computation Client (PCC) to establish a connection
with a PCE server using TLS or TCP-AO, PCC needs to know whether PCE
server supports TLS or TCP-AO as a secure transport.
[RFC5088] and [RFC5089] define a method to advertise path computation
capabilities using IGP flooding for OSPF and IS-IS respectively.
However these specifications lack a method to advertise PCEP security
(e.g., TLS) support capability.
This document defines capability flag bits for PCE-CAP-FLAGS sub-TLV
that can be announced as attributes in the IGP advertisement to
distribute PCEP security support information. In addition, this
document updates RFC5088 and RFC5089 to allow advertisement of Key ID
or Key Chain Name Sub-TLV to support TCP-AO security capability.
Note that the PCEP Open message exchange is another way to discover
PCE capabilities information, but in this instance, the TCP security
related key parameters need to be known before the PCEP session is
established and the PCEP Open messages are exchanged. Thus, the use
of the PCE discovery and capabilities advertisement of the IGP needs
to be leveraged.
2. Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. IGP extension for PCEP security capability support
[RFC5088] defines a PCE Discovery (PCED) TLV carried in an OSPF
Router Information Link State Advertisement (LSA) as defined in
[RFC7770] to facilitate PCE discovery using OSPF. This document
defines two capability flag bits in the OSPF PCE Capability Flags to
indicate TCP Authentication Option (TCP-AO) support
[RFC5925][RFC5926] and PCEP over TLS support [RFC8253] respectively.
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Similarly, [RFC5089] defines the PCED sub-TLV for use in PCE
discovery using IS-IS. This document will use the same flag for the
OSPF PCE Capability Flags sub-TLV to allow IS-IS to indicate TCP
Authentication Option (TCP-AO) support, PCEP over TLS support
respectively.
The IANA assignments for shared OSPF and IS-IS Security Capability
Flags are documented in Section 8.1 ("OSPF PCE Capability Flags") of
this document.
3.1. Use of PCEP security capability support for PCE discovery
TCP-AO, PCEP over TLS support flag bits are advertised using IGP
flooding.
* PCE supports TCP-AO: IGP advertisement SHOULD include TCP-AO
support flag bit.
* PCE supports TLS: IGP advertisement SHOULD include PCEP over TLS
support flag bit.
If PCE supports multiple security mechanisms, it SHOULD include all
corresponding flag bits in IGP advertisement.
If the client is restricted to a PCE server with TCP-AO support, the
client MUST check if TCP-AO support flag bit in the PCE- CAP-FLAGS
sub-TLV is set. If not, the client SHOULD NOT consider this PCE. If
the client is restriced to a PCE server using TLS, the client MUST
check if PCEP over TLS support flag bit in the PCE-CAP-FLAGS sub-TLV
is set. If not, the client SHOULD NOT consider this PCE. Note that
this can be overridden based on a local policy at the PCC.
3.2. KEY-ID Sub-TLV
The KEY-ID sub-TLV specifies a key that can be used by the PCC to
identify the TCP-AO key [RFC5925].
The KEY-ID sub-TLV MAY be present in the PCED sub-TLV carried within
the IS-IS Router Information Capability TLV when the capability flag
bit of PCE-CAP-FLAGS sub-TLV in IS-IS is set to indicate TCP
Authentication Option (TCP-AO) support. Similarly, this sub-TLV MAY
be present in the PCED TLV carried within OSPF Router Information LSA
when the capability flag bit of PCE-CAP-FLAGS sub-TLV in OSPF is set
to indicate TCP-AO support.
The KEY-ID sub-TLV has the following format:
Type: 6
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Length: 4
KeyID: The one octet Key ID as per [RFC5925] to uniquely identify
the Master Key Tuple (MKT).
Reserved: MUST be set to zero while sending and ignored on
receipt.
3.3. KEY-CHAIN-NAME Sub-TLV
The KEY-CHAIN-NAME sub-TLV specifies a keychain name that can be used
by the PCC to identify the keychain [RFC8177].
The KEY-CHAIN-NAME sub-TLV MAY be present in the PCED sub-TLV carried
within the IS-IS Router Information Capability TLV when the
capability flag bit of PCE-CAP-FLAGS sub-TLV in IS-IS is set to
indicate TCP Authentication Option (TCP-AO) support. Similarly, this
sub-TLV MAY be present in the PCED TLV carried within OSPF Router
Information LSA when the capability flag bit of PCE-CAP-FLAGS sub-TLV
in OSPF is set to indicate TCP-AO support.
The KEY-CHAIN-NAME sub-TLV has the following format:
Type: 7
Length: Variable
Key Name: The Key Chain Name contains a string to be used to
identify the key chain. It SHOULD be a string of printable ASCII
characters, without a NULL terminator. The sub-TLV MUST be zero-
padded so that the sub-TLV is 4-octet aligned.
4. Update to RFC5088 and RFC5089
Section 4 of [RFC5088] states that no new sub-TLVs will be added to
the PCED TLV, and no new PCE information will be carried in the
Router Information LSA. This document updates [RFC5088] by allowing
the two sub-TLVs defined in this document to be carried in the PCED
TLV advertised in the Router Information LSA.
Section 4 of [RFC5089] states that no new sub-TLVs will be added to
the PCED TLV, and no new PCE information will be carried in the
Router CAPABLITY TLV. This document updates [RFC5089] by allowing
the two sub-TLVs defined in this document to be carried in the PCED
TLV advertised in the Router CAPABILITY TLV.
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The introduction of the additional sub-TLVs should be viewed as an
exception to the [RFC5088][RFC5089] policy justified by the
requirements to discover the PCEP security support prior to
establishing a PCEP session. The restrictions defined in
[RFC5089][RFC5089] should still be considered to be in place.
The registry for the PCE Capability Flags assigned in section 8.2 of
[RFC8231], section 6.9 of [RFC8306], and section 11.1 of [RFC8623]
has changed to the IGP Parameters "Path Computation Element (PCE)
Capability Flags" registry created in this document.
5. Backward Compatibility Consideration
An LSR that does not support the IGP PCE capability bits specified in
this document silently ignores those bits.
An LSR that does not support the KEYNAME sub-TLV specified in this
document silently ignores the sub-TLV.
IGP extensions defined in this document do not introduce any new
interoperability issues.
6. Management Considerations
A configuration option may be provided for advertising and
withdrawing PCEP security capability via OSPF and IS-IS.
7. Security Considerations
Security considerations as specified by [RFC5088] and [RFC5089] are
applicable to this document.
The information related to PCEP security is sensitive and due care
needs to be taken by the operator. This document defines new
capability bits that are susceptible to a downgrade attack by
toggling them. The content of Key ID or Key Chain Name Sub-TLV can
be tweaked to enable a man-in-the-middle attack. Thus before
advertising the PCEP security parameters, using the mechanism
described in this document, the IGP MUST be known to provide
authentication and integrity for the PCED TLV using the mechanisms
defined in [RFC5304], [RFC5310] or [RFC5709].
Moreover, as stated in [RFC5088] and [RFC5089], if the IGP does not
provide any encryption mechanisms to protect the secrecy of the PCED
TLV, then the operator must ensure that no private data is carried in
the TLV, e.g. that key-ids or key-chain names do not reveal sensitive
information about the network.
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8. IANA Considerations
8.1. PCE Capability Flag
IANA is requested to move the "PCE Capability Flags" registry from
"Open Shortest Path First v2 (OSPFv2) Parameters" to under the IANA
Common IGP parameters registry and allocate new bits assignments for
the IGP Parameters "Path Computation Element (PCE) Capability Flags"
registry.
Bit Meaning Reference
xx TCP-AO Support [This.I.D]
xx PCEP over TLS support [This.I.D]
The registry is located at: https://www.iana.org/assignments/igp-
parameters/igp-parameters.xhtml
8.2. PCED sub-TLV Type Indicators
The PCED sub-TLVs were defined in [RFC5088] and [RFC5089], but they
did not create a registry for it. This document requests IANA to
create a new subregistry called "PCED sub-TLV type indicators" under
the "Interior Gateway Protocol (IGP) Parameters" registry. The
registration policy for this subregistry is "IETF Review" [RFC8126].
Values in this subregistry come from the range 0-65535.
This subregistry should be populated with:
Value Description Reference
0 Reserved [This.I.D][RFC5088]
1 PCE-ADDRESS [This.I.D][RFC5088]
2 PATH-SCOPE [This.I.D][RFC5088]
3 PCE-DOMAIN [This.I.D][RFC5088]
5 PCE-CAP-FLAGS [This.I.D][RFC5088]
4 NEIG-PCE-DOMAIN [This.I.D][RFC5088]
6 KEY-ID [This.I.D]
7 KEY-CHAIN-NAME [This.I.D]
This registry is located at: https://www.iana.org/assignments/igp-
parameters/igp-parameters.xhtml and used by both OSPF PCED TLV and
IS-IS PCED sub-TLV.
9. Acknowledgments
The authors of this document would also like to thank Acee Lindem,
Julien Meuric, Les Ginsberg, Ketan Talaulikar, Yaron Sheffer, Tom
Petch, Aijun Wang, Adrian Farrel for the review and comments.
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The authors would also like to speical thank Michale Wang for his
major contributions to the initial version.
10. References
10.1. 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,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC5088] Le Roux, JL., Ed., Vasseur, JP., Ed., Ikejiri, Y., and R.
Zhang, "OSPF Protocol Extensions for Path Computation
Element (PCE) Discovery", RFC 5088, DOI 10.17487/RFC5088,
January 2008, <https://www.rfc-editor.org/info/rfc5088>.
[RFC5089] Le Roux, JL., Ed., Vasseur, JP., Ed., Ikejiri, Y., and R.
Zhang, "IS-IS Protocol Extensions for Path Computation
Element (PCE) Discovery", RFC 5089, DOI 10.17487/RFC5089,
January 2008, <https://www.rfc-editor.org/info/rfc5089>.
[RFC5925] Touch, J., Mankin, A., and R. Bonica, "The TCP
Authentication Option", RFC 5925, DOI 10.17487/RFC5925,
June 2010, <https://www.rfc-editor.org/info/rfc5925>.
[RFC5926] Lebovitz, G. and E. Rescorla, "Cryptographic Algorithms
for the TCP Authentication Option (TCP-AO)", RFC 5926,
DOI 10.17487/RFC5926, June 2010,
<https://www.rfc-editor.org/info/rfc5926>.
[RFC8253] Lopez, D., Gonzalez de Dios, O., Wu, Q., and D. Dhody,
"PCEPS: Usage of TLS to Provide a Secure Transport for the
Path Computation Element Communication Protocol (PCEP)",
RFC 8253, DOI 10.17487/RFC8253, October 2017,
<https://www.rfc-editor.org/info/rfc8253>.
[RFC8177] Lindem, A., Ed., Qu, Y., Yeung, D., Chen, I., and J.
Zhang, "YANG Data Model for Key Chains", RFC 8177,
DOI 10.17487/RFC8177, June 2017,
<https://www.rfc-editor.org/info/rfc8177>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
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[RFC7770] Lindem, A., Ed., Shen, N., Vasseur, JP., Aggarwal, R., and
S. Shaffer, "Extensions to OSPF for Advertising Optional
Router Capabilities", RFC 7770, DOI 10.17487/RFC7770,
February 2016, <https://www.rfc-editor.org/info/rfc7770>.
[RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic
Authentication", RFC 5304, DOI 10.17487/RFC5304, October
2008, <https://www.rfc-editor.org/info/rfc5304>.
[RFC5310] Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R.,
and M. Fanto, "IS-IS Generic Cryptographic
Authentication", RFC 5310, DOI 10.17487/RFC5310, February
2009, <https://www.rfc-editor.org/info/rfc5310>.
[RFC5709] Bhatia, M., Manral, V., Fanto, M., White, R., Barnes, M.,
Li, T., and R. Atkinson, "OSPFv2 HMAC-SHA Cryptographic
Authentication", RFC 5709, DOI 10.17487/RFC5709, October
2009, <https://www.rfc-editor.org/info/rfc5709>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
[RFC8231] Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path
Computation Element Communication Protocol (PCEP)
Extensions for Stateful PCE", RFC 8231,
DOI 10.17487/RFC8231, September 2017,
<https://www.rfc-editor.org/info/rfc8231>.
[RFC8306] Zhao, Q., Dhody, D., Ed., Palleti, R., and D. King,
"Extensions to the Path Computation Element Communication
Protocol (PCEP) for Point-to-Multipoint Traffic
Engineering Label Switched Paths", RFC 8306,
DOI 10.17487/RFC8306, November 2017,
<https://www.rfc-editor.org/info/rfc8306>.
[RFC8623] Palle, U., Dhody, D., Tanaka, Y., and V. Beeram, "Stateful
Path Computation Element (PCE) Protocol Extensions for
Usage with Point-to-Multipoint TE Label Switched Paths
(LSPs)", RFC 8623, DOI 10.17487/RFC8623, June 2019,
<https://www.rfc-editor.org/info/rfc8623>.
10.2. Informative References
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[RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol (PCEP)", RFC 5440,
DOI 10.17487/RFC5440, March 2009,
<https://www.rfc-editor.org/info/rfc5440>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
Appendix A. No MD5 Capability Support
To be compliant with Section 10.2 of RFC5440, this document doesn't
consider adding capability for TCP-MD5. Therefore by default, a PCEP
Speaker supports the capability for TCP-MD5 (See section 10.2,
[RFC5440]). A method to advertise TCP-MD5 Capability support using
IGP flooding is not required. If the client is looking for a PCE
server with other Security capability support (e.g., TLS support)
than TCP-MD5, the client MUST check if the corresponding flag bit in
the PCE-CAP-FLAGS sub-TLV is set (See section 3.1). Irrespective of
which security capability (e.g., TCP-MD5) is selected, the same key-
ids or key-chain names on the PCC and PCE server should be
configured.
Authors' Addresses
Diego R. Lopez
Telefonica I+D
Spain
Email: diego.r.lopez@telefonica.com
Qin Wu
Huawei Technologies
101 Software Avenue, Yuhua District
Nanjing
Jiangsu, 210012
China
Email: bill.wu@huawei.com
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Dhruv Dhody
Huawei Technologies
Divyashree Techno Park, Whitefield
Bangalore 560037
Karnataka
India
Email: dhruv.ietf@gmail.com
Qiufang Ma
Huawei
101 Software Avenue, Yuhua District
Nanjing
Jiangsu, 210012
China
Email: maqiufang1@huawei.com
Daniel King
Old Dog Consulting
United Kingdom
Email: daniel@olddog.co.uk
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