IKEv2 Optional SA&TS Payloads in Child Exchange
draft-kampati-ipsecme-ikev2-sa-ts-payloads-opt-01
The information below is for an old version of the document.
| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Authors | Sandeep Kampati , Meduri S S Bharath , Wei Pan | ||
| Last updated | 2019-05-21 (Latest revision 2019-02-18) | ||
| Stream | (None) | ||
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| Stream | Stream state | (No stream defined) | |
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| Send notices to | (None) |
draft-kampati-ipsecme-ikev2-sa-ts-payloads-opt-01
IPSECME S. Kampati
Internet-Draft M. Bharath
Intended status: Standards Track W. Pan
Expires: November 22, 2019 Huawei
May 21, 2019
IKEv2 Optional SA&TS Payloads in Child Exchange
draft-kampati-ipsecme-ikev2-sa-ts-payloads-opt-01
Abstract
This document describes a method for reducing the size of the
Internet Key Exchange version 2 (IKEv2) exchanges at time of rekeying
IKE SAs and Child SAs by removing or making optional of SA & TS
payloads. Reducing size of IKEv2 exchanges is desirable for low
power consumption battery powered devices. It also helps to avoid IP
fragmentation of IKEv2 messages.
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 November 22, 2019.
Copyright Notice
Copyright (c) 2019 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
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include Simplified BSD License text as described in Section 4.e of
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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
2.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
3. Protocol Details . . . . . . . . . . . . . . . . . . . . . . 3
3.1. Negotiation of Support for Optimizing Optional Payload at
Rekeying IKE SAs and Child SAs . . . . . . . . . . . . . 3
3.2. Optional Payload Optimization at Rekeying IKE SAs . . . . 4
3.2.1. Rekeying IKE SAs When No Change of Initiator and
Responder's Cryptographic Suites . . . . . . . . . . 4
3.2.2. Rekeying IKE SAs When Initiator's Cryptographic
Suites Changed . . . . . . . . . . . . . . . . . . . 5
3.2.3. Rekeying IKE SAs When Responder's Cryptographic
Suites Changed . . . . . . . . . . . . . . . . . . . 5
3.3. Optional Payload Optimization at Rekeying Child SAs . . . 6
3.3.1. Rekeying Child SAs When No Change of Initiator and
Responder's Cryptographic Suites and ACL
Configuration . . . . . . . . . . . . . . . . . . . . 6
3.3.2. Rekeying Child SAs When Initiator's Cryptographic
Suites or ACL Configuration Changed . . . . . . . . . 7
3.3.3. Rekeying Child SAs When Responder's Cryptographic
Suites or ACL Configuration Changed . . . . . . . . . 7
4. Payload Formats . . . . . . . . . . . . . . . . . . . . . . . 8
4.1. MINIMAL_REKEY_SUPPORTED Notification . . . . . . . . . . 8
4.2. SA_UNCHANGED Notification . . . . . . . . . . . . . . . . 9
4.3. SA_TS_UNCHANGED Notification . . . . . . . . . . . . . . 9
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
6. Security Considerations . . . . . . . . . . . . . . . . . . . 10
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
7.1. Normative References . . . . . . . . . . . . . . . . . . 10
7.2. Informative References . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction
The Internet Key Exchange protocol version 2 (IKEv2) specified in
[RFC7296] is used in the IP Security (IPsec) architecture for the
purposes of Security Association (SA) parameters negotiation and
authenticated key exchange. The protocol uses UDP as the transport
for its messages, which size varies from less than one hundred bytes
to several kBytes.
In 4G networks security gateways/ePDG and in 5G networks cRAN/Cloud
will support more than 100,000 IKE/IPSEC tunnels. So on an average,
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for every second there may be hundreds or thousands of IKE SAs and
Child SAs that are rekeying. This takes huge amount of bandwidth,
packet fragmentation and more processing resources. And it can be
solved by introducing the solution described in this document.
This is useful in Internet of Things (IoT) devices which utilizing
lower power consumption technology. The appendix A of
[I-D.mglt-6lo-diet-esp-requirements] gives some estimate data.
Most devices don't prefer to change cryptographic suites frequently.
By taking this advantage the SA and TS payloads can be made optional
at the time of rekeying IKE SAs and Child SAs. In such situation,
only a new SPI value is needed to create the new IKE SA and Child SA.
So a new Notify payload which contains the needed SPI value can be
sent instead of the SA and TS payloads.
In case of rekeying IKE SAs, the SA payloads can be optimized if
there is no change of cryptographic suites. In case of rekeying
Child SAs, the SA and TS payloads can be optimized if there is no
change of cryptographic suites and ACL configuration.
2. Conventions Used in This Document
2.1. Requirements Language
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. Protocol Details
This section provides protocol details and contains the normative
parts.
3.1. Negotiation of Support for Optimizing Optional Payload at Rekeying
IKE SAs and Child SAs
The initiator indicates its support for optimizing optional payloads
at rekeying IKE SAs and Child SAs by including a Notify payload of
type MINIMAL_REKEY_SUPPORTED in the IKE_AUTH request message. If the
responder also supports this extension, it includes the
MINIMAL_REKEY_SUPPORTED notification in the response message. If the
responder doesn't support this extension, it MUST ignore the
MINIMAL_REKEY_SUPPORTED notification sent by the initiator and MUST
NOT respond error to the initiator.
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The IKE_AUTH message exchange in this case is shown below:
Initiator Responder
--------------------------------------------------------------------
HDR, SK {IDi, [CERT,] [CERTREQ,]
[IDr,] AUTH, SAi2, TSi, TSr,
N(MINIMAL_REKEY_SUPPORTED)} -->
<-- HDR, SK {IDr, [CERT,] AUTH,
SAr2, TSi, TSr,
N(MINIMAL_REKEY_SUPPORTED)}
3.2. Optional Payload Optimization at Rekeying IKE SAs
The payload optimization at rekeying IKE SAs MUST NOT be used unless
both peers have indicated their support of this extension by using
the negotiation method described in Section 3.1. If the initiator or
responder decides to use this payload optimization, then it includes
the SA_UNCHANGED notification in its CREATE_CHILD_SA exchange message
at the time of rekeying IKE SAs. This SA_UNCHANGED notification MUST
be included in a CREATE_CHILD_SA exchange message when there is no SA
payloads included. The new IKE SA is created with the SPI value in
the SA_UNCHANGED notification.
3.2.1. Rekeying IKE SAs When No Change of Initiator and Responder's
Cryptographic Suites
At the time of rekeying IKE SAs, the initiator MAY send the
SA_UNCHANGED notification payload instead of the SA payloads when
there is no change in its cryptographic suites since last
negotiation. After receiving the initiator's request message with
the SA_UNCHANGED notification, the responder MAY respond to the
initiator with the SA_UNCHANGED notification payload instead of the
SA payloads if there is also no change in its cryptographic suites
since last negotiation.
The CREATE_CHILD_SA message exchange in this case is shown below:
Initiator Responder
--------------------------------------------------------------------
HDR, SK {N(SA_UNCHANGED), Ni, KEi} -->
<-- HDR, SK {N(SA_UNCHANGED), Nr, KEr}
The initiator sends a SA_UNCHANGED notification payload, a Nonce
payload and a Diffie-Hellman value in the KEi payload. A new
initiator SPI is supplied in the SPI field of the SA_UNCHANGED
notification payload.
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The responder replies (using the same Message ID to respond) with a
SA_UNCHANGED notification payload, a Nonce payload and a Diffie-
Hellman value in the KEr payload. A new responder SPI is supplied in
the SPI field of the SA_UNCHANGED notification payload.
When the SA_UNCHANGED notification payload is included, the SA
payload MUST NOT be included.
3.2.2. Rekeying IKE SAs When Initiator's Cryptographic Suites Changed
At the time of or before rekeying IKE SAs, the initiator's
cryptographic suites may be changed while there is no change of
responder's cryptographic suites. New cryptographic suites may be
added to the initiator, or some outdated cryptographic suites may be
deleted from the initiator.
In this situation, the initiator MUST send the SA payloads in the
CREATE_CHILD_SA request message at the time of rekeying IKE SAs.
If the responder selects a different cryptographic suite than which
was previously negotiated, then the rekeying MUST be conducted in the
original way defined in [RFC7296], the responder sends the SA
payloads with the selected cryptographic suite in the CREATE_CHILD_SA
response message.
If the responder selects the previously negotiated cryptographic
suite to rekey the IKE SA, it MAY send the SA_UNCHANGED notification
payload instead of the SA payload in the CREATE_CHILD_SA response
message, and the initiator MUST use the cryptographic suite
negotiated previously to create the new IKE SA. The CREATE_CHILD_SA
message exchange in this case is shown below:
Initiator Responder
--------------------------------------------------------------------
HDR, SK {SA, Ni, KEi} -->
<-- HDR, SK {N(SA_UNCHANGED), Nr, KEr}
3.2.3. Rekeying IKE SAs When Responder's Cryptographic Suites Changed
At the time of or before rekeying IKE SAs, the responder's
cryptographic suites may be changed while there is no change of
initiator's cryptographic suites. New cryptographic suites may be
added to the responder, or some outdated cryptographic suites may be
deleted from the responder.
In this situation, the initiator sends the SA_UNCHANGED notification
payload instead of the SA payloads in the CREATE_CHILD_SA request
message at the time of rekeying IKE SAs.
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If the responder decides to continue using the previously negotiated
cryptographic suite to rekey the IKE SA, it MAY send the SA_UNCHANGED
notification payload in the CREATE_CHILD_SA response message, then
the rekeying is conducted like Section 3.2.1.
If the responder decides to re-negotiate the cryptographic suite, it
MUST send NO_PROPOSAL_CHOSEN notification payload in the
CREATE_CHILD_SA response message. After receiving this error
notification, the initiator MUST retry the CREATE_CHILD_SA exchange
with the SA payloads. Then the rekeying is conducted in the original
way defined in [RFC7296]. The CREATE_CHILD_SA message exchange in
this case is shown below:
Initiator Responder
--------------------------------------------------------------------
HDR, SK {N(SA_UNCHANGED), Ni, KEi} -->
<-- HDR, SK {N(NO_PROPOSAL_CHOSEN),
Nr, KEr}
HDR, SK {SA, Ni, KEi} -->
<-- HDR, SK {SA, Ni, KEi}
3.3. Optional Payload Optimization at Rekeying Child SAs
The payload optimization at rekeying Child SAs MUST NOT be used
unless both peers have indicated their support of this extension by
using the negotiation method described in Section 3.1. If the
initiator or responder decides to use this payload optimization, then
it includes the SA_TS_UNCHANGED notification in its CREATE_CHILD_SA
exchange message at the time of rekeying Child SAs. This
SA_TS_UNCHANGED notification MUST be included in a CREATE_CHILD_SA
exchange message when there is no SA and TS payloads included. The
new Child SA is created with the SPI value in the SA_TS_UNCHANGED
notification.
3.3.1. Rekeying Child SAs When No Change of Initiator and Responder's
Cryptographic Suites and ACL Configuration
At the time of rekeying Child SAs, the initiator MAY send the
SA_TS_UNCHANGED notification payload instead of the SA and TS
payloads when there is no change in its cryptographic suites and ACL
configuration since last negotiation. After receiving the
initiator's request message with the SA_TS_UNCHANGED notification,
the responder MAY respond to the initiator with the SA_TS_UNCHANGED
notification payload instead of the SA and TS payloads if there is
also no change in its cryptographic suites and ACL configuration
since last negotiation.
The CREATE_CHILD_SA message exchange in this case is shown below:
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Initiator Responder
--------------------------------------------------------------------
HDR, SK {N(REKEY_SA), N(SA_TS_UNCHANGED),
Ni, [KEi,]} -->
<-- HDR, SK {N(SA_TS_UNCHANGED),
Nr, [KEr,]}
3.3.2. Rekeying Child SAs When Initiator's Cryptographic Suites or ACL
Configuration Changed
At the time of or before rekeying Child SAs, the initiator's
cryptographic suites or ACL configuration may be changed while there
is no change of responder's cryptographic suites and ACL
configuration.
In this situation, the initiator MUST send the SA and TS payloads in
the CREATE_CHILD_SA request message at the time of rekeying Child
SAs.
If the responder selects a different cryptographic suite or different
Traffic Selectors than which were previously negotiated, then the
rekeying MUST be conducted in the original way defined in [RFC7296],
the responder sends the SA payloads with the selected cryptographic
suite and the TS payloads in the CREATE_CHILD_SA response message.
If the responder selects the previously negotiated cryptographic
suite and Traffic Selectors to rekey the Child SA, it MAY send the
SA_TS_UNCHANGED notification payload instead of the SA and TS
payloads in the CREATE_CHILD_SA response message, and the initiator
MUST use the cryptographic suite and Traffic Selectors negotiated
previously to create the new Child SA. The CREATE_CHILD_SA message
exchange in this case is shown below:
Initiator Responder
--------------------------------------------------------------------
HDR, SK {N(REKEY_SA), SA, Ni, [KEi,]
TSi, TSr} -->
<-- HDR, SK {N(SA_TS_UNCHANGED),
Nr, KEr}
3.3.3. Rekeying Child SAs When Responder's Cryptographic Suites or ACL
Configuration Changed
At the time of or before rekeying Child SAs, the responder's
cryptographic suites or ACL configuration may be changed while there
is no change of initiator's cryptographic suites and ACL
configuration.
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In this situation, the initiator MAY send the SA_TS_UNCHANGED
notification payload instead of the SA and TS payloads in the
CREATE_CHILD_SA request message at the time of rekeying Child SAs.
If the responder decides to continue using the previously negotiated
cryptographic suite and Traffic Selectors to rekey the Child SA, it
MAY send the SA_TS_UNCHANGED notification payload in the
CREATE_CHILD_SA response message, then the rekeying is conducted like
Section 3.3.1.
If the responder decides to re-negotiate the cryptographic suite or
Traffic Selectors, it MUST send NO_PROPOSAL_CHOSEN notification
payload in the CREATE_CHILD_SA response message. After receiving
this error notification, the initiator MUST retry the CREATE_CHILD_SA
exchange with the SA and TS payloads. Then the rekeying is conducted
in the original way defined in [RFC7296]. The CREATE_CHILD_SA
message exchange in this case is shown below:
Initiator Responder
--------------------------------------------------------------------
HDR, SK {N(SA_TS_UNCHANGED), Ni, KEi} -->
<-- HDR, SK {N(NO_PROPOSAL_CHOSEN),
Nr, KEr}
HDR, SK {N(REKEY_SA), SA, Ni, [KEi,]
TSi, TSr} -->
<-- HDR, SK {SA, Nr, [KEr,]
TSi, TSr}
4. Payload Formats
4.1. MINIMAL_REKEY_SUPPORTED Notification
The MINIMAL_REKEY_SUPPORTED notification is used by the initiator and
responder to inform their ability of optimizing optional payload at
the time of rekeying IKE SAs and Child SAs to the peers. It is
formatted as follows:
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Next Payload |C| RESERVED | Payload Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Protocol ID(=0)| SPI Size (=0) | Notify Message Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Protocol ID (1 octet) - MUST be 0.
o SPI Size (1 octet) - MUST be 0, meaning no SPI is present.
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o Notify Message Type (2 octets) - MUST be <Need to get value from
IANA>, the value assigned for the MINIMAL_REKEY_SUPPORTED
notification.
This notification contains no data.
4.2. SA_UNCHANGED Notification
The SA_UNCHANGED notification is used to replace the SA payloads at
the time of rekeying IKE SAs when there is no change of cryptographic
suites in initiator or responder. It is formatted as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Next Payload |C| RESERVED | Payload Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Protocol ID | SPI Size (=8) | Notify Message Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Security Parameter Index (SPI) |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Protocol ID (1 octet) - MUST be 1.
o SPI Size (1 octet) - MUST be 8.
o Notify Message Type (2 octets) - MUST be <Need to get value from
IANA>, the value assigned for the SA_UNCHANGED notification.
o SPI (8 octets) - Security Parameter Index. The initiator sends
initiator SPI. The responder sends responder SPI.
4.3. SA_TS_UNCHANGED Notification
The SA_TS_UNCHANGED notification is used to replace the SA payloads
and TS payloads at the time of rekeying Child SAs when there is no
change of cryptographic suites and ACL configuration in initiator or
responder. It is formatted as follows:
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Next Payload |C| RESERVED | Payload Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Protocol ID | SPI Size (=4) | Notify Message Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Security Parameter Index (SPI) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Protocol ID (1 octet) - MUST be either (2) to indicate AH or (3)
to indicate ESP.
o SPI Size (1 octet) - MUST be 4.
o Notify Message Type (2 octets) - MUST be <Need to get value from
IANA>, the value assigned for the SA_TS_UNCHANGED notification.
o SPI (4 octets) - Security Parameter Index. The initiator sends
initiator SPI. The responder sends responder SPI.
5. IANA Considerations
This document defines two new Notify Message Types in the "IKEv2
Notify Message Types - Status Types" registry. IANA is requested to
assign codepoints in this registry.
NOTIFY messages: status types Value
----------------------------------------------------------
MINIMAL_REKEY_SUPPORTED TBD
SA_UNCHANGED TBD
SA_TS_UNCHANGED TBD
6. Security Considerations
TBD
7. References
7.1. 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>.
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[RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
Kivinen, "Internet Key Exchange Protocol Version 2
(IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October
2014, <https://www.rfc-editor.org/info/rfc7296>.
[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>.
7.2. Informative References
[I-D.mglt-6lo-diet-esp-requirements]
Migault, D., Guggemos, T., and C. Bormann, "Requirements
for Diet-ESP the IPsec/ESP protocol for IoT", draft-mglt-
6lo-diet-esp-requirements-02 (work in progress), July
2016.
Authors' Addresses
Sandeep Kampati
Huawei Technologies
Divyashree Techno Park, Whitefield
Bangalore, Karnataka 560066
India
Email: sandeepkampati@huawei.com
Meduri S S Bharath
Huawei Technologies
Divyashree Techno Park, Whitefield
Bangalore, Karnataka 560066
India
Email: MeduriS.Bharath@huawei.com
Wei Pan
Huawei Technologies
101 Software Avenue, Yuhuatai District
Nanjing, Jiangsu
China
Email: william.panwei@huawei.com
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