draft-ietf-ipsecme-failure-detection-07.txt   draft-ietf-ipsecme-failure-detection-08.txt 
IPsecME Working Group Y. Nir, Ed. IPsecME Working Group Y. Nir, Ed.
Internet-Draft Check Point Internet-Draft Check Point
Intended status: Standards Track D. Wierbowski Intended status: Standards Track D. Wierbowski
Expires: September 29, 2011 IBM Expires: October 3, 2011 IBM
F. Detienne F. Detienne
P. Sethi P. Sethi
Cisco Cisco
March 28, 2011 April 1, 2011
A Quick Crash Detection Method for IKE A Quick Crash Detection Method for IKE
draft-ietf-ipsecme-failure-detection-07 draft-ietf-ipsecme-failure-detection-08
Abstract Abstract
This document describes an extension to the IKEv2 protocol that This document describes an extension to the IKEv2 protocol that
allows for faster detection of Security Association (SA) allows for faster detection of Security Association (SA)
desynchronization using a saved token. desynchronization using a saved token.
When an IPsec tunnel between two IKEv2 peers is disconnected due to a When an IPsec tunnel between two IKEv2 peers is disconnected due to a
restart of one peer, it can take as much as several minutes for the restart of one peer, it can take as much as several minutes for the
other peer to discover that the reboot has occurred, thus delaying other peer to discover that the reboot has occurred, thus delaying
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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 29, 2011. This Internet-Draft will expire on October 3, 2011.
Copyright Notice Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the Copyright (c) 2011 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
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1.1. Conventions Used in This Document . . . . . . . . . . . . 4 1.1. Conventions Used in This Document . . . . . . . . . . . . 4
2. RFC 5996 Crash Recovery . . . . . . . . . . . . . . . . . . . 5 2. RFC 5996 Crash Recovery . . . . . . . . . . . . . . . . . . . 5
3. Protocol Outline . . . . . . . . . . . . . . . . . . . . . . . 6 3. Protocol Outline . . . . . . . . . . . . . . . . . . . . . . . 6
4. Formats and Exchanges . . . . . . . . . . . . . . . . . . . . 7 4. Formats and Exchanges . . . . . . . . . . . . . . . . . . . . 7
4.1. Notification Format . . . . . . . . . . . . . . . . . . . 7 4.1. Notification Format . . . . . . . . . . . . . . . . . . . 7
4.2. Passing a Token in the AUTH Exchange . . . . . . . . . . 8 4.2. Passing a Token in the AUTH Exchange . . . . . . . . . . 8
4.3. Replacing Tokens After Rekey or Resumption . . . . . . . 9 4.3. Replacing Tokens After Rekey or Resumption . . . . . . . 9
4.4. Replacing the Token for an Existing SA . . . . . . . . . 10 4.4. Replacing the Token for an Existing SA . . . . . . . . . 10
4.5. Presenting the Token in an Unprotected Message . . . . . 10 4.5. Presenting the Token in an Unprotected Message . . . . . 10
5. Token Generation and Verification . . . . . . . . . . . . . . 11 5. Token Generation and Verification . . . . . . . . . . . . . . 11
5.1. A Stateless Method of Token Generation . . . . . . . . . 11 5.1. A Stateless Method of Token Generation . . . . . . . . . 12
5.2. A Stateless Method with IP addresses . . . . . . . . . . 12 5.2. A Stateless Method with IP addresses . . . . . . . . . . 12
5.3. Token Lifetime . . . . . . . . . . . . . . . . . . . . . 12 5.3. Token Lifetime . . . . . . . . . . . . . . . . . . . . . 13
6. Backup Gateways . . . . . . . . . . . . . . . . . . . . . . . 13 6. Backup Gateways . . . . . . . . . . . . . . . . . . . . . . . 13
7. Interaction with Session Resumption . . . . . . . . . . . . . 13 7. Interaction with Session Resumption . . . . . . . . . . . . . 13
8. Operational Considerations . . . . . . . . . . . . . . . . . . 15 8. Operational Considerations . . . . . . . . . . . . . . . . . . 15
8.1. Who should implement this specification . . . . . . . . . 15 8.1. Who should implement this specification . . . . . . . . . 15
8.2. Response to unknown child SPI . . . . . . . . . . . . . . 16 8.2. Response to unknown child SPI . . . . . . . . . . . . . . 16
9. Security Considerations . . . . . . . . . . . . . . . . . . . 16 9. Security Considerations . . . . . . . . . . . . . . . . . . . 17
9.1. QCD Token Generation and Handling . . . . . . . . . . . . 16 9.1. QCD Token Generation and Handling . . . . . . . . . . . . 17
9.2. QCD Token Transmission . . . . . . . . . . . . . . . . . 17 9.2. QCD Token Transmission . . . . . . . . . . . . . . . . . 18
9.3. QCD Token Enumeration . . . . . . . . . . . . . . . . . . 18 9.3. QCD Token Enumeration . . . . . . . . . . . . . . . . . . 18
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 18 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 19
12. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . . 19 12. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . . 19
12.1. Changes from draft-ietf-ipsecme-failure-detection-05 . . 19 12.1. Changes from draft-ietf-ipsecme-failure-detection-05 . . 19
12.2. Changes from draft-ietf-ipsecme-failure-detection-04 . . 19 12.2. Changes from draft-ietf-ipsecme-failure-detection-04 . . 19
12.3. Changes from draft-ietf-ipsecme-failure-detection-03 . . 19 12.3. Changes from draft-ietf-ipsecme-failure-detection-03 . . 20
12.4. Changes from draft-ietf-ipsecme-failure-detection-02 . . 19 12.4. Changes from draft-ietf-ipsecme-failure-detection-02 . . 20
12.5. Changes from draft-ietf-ipsecme-failure-detection-01 . . 19 12.5. Changes from draft-ietf-ipsecme-failure-detection-01 . . 20
12.6. Changes from draft-ietf-ipsecme-failure-detection-00 . . 19 12.6. Changes from draft-ietf-ipsecme-failure-detection-00 . . 20
12.7. Changes from draft-nir-ike-qcd-07 . . . . . . . . . . . . 20 12.7. Changes from draft-nir-ike-qcd-07 . . . . . . . . . . . . 20
12.8. Changes from draft-nir-ike-qcd-03 and -04 . . . . . . . . 20 12.8. Changes from draft-nir-ike-qcd-03 and -04 . . . . . . . . 21
12.9. Changes from draft-nir-ike-qcd-02 . . . . . . . . . . . . 20 12.9. Changes from draft-nir-ike-qcd-02 . . . . . . . . . . . . 21
12.10. Changes from draft-nir-ike-qcd-01 . . . . . . . . . . . . 20 12.10. Changes from draft-nir-ike-qcd-01 . . . . . . . . . . . . 21
12.11. Changes from draft-nir-ike-qcd-00 . . . . . . . . . . . . 20 12.11. Changes from draft-nir-ike-qcd-00 . . . . . . . . . . . . 21
12.12. Changes from draft-nir-qcr-00 . . . . . . . . . . . . . . 21 12.12. Changes from draft-nir-qcr-00 . . . . . . . . . . . . . . 21
13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 21 13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 21
13.1. Normative References . . . . . . . . . . . . . . . . . . 21 13.1. Normative References . . . . . . . . . . . . . . . . . . 21
13.2. Informative References . . . . . . . . . . . . . . . . . 21 13.2. Informative References . . . . . . . . . . . . . . . . . 22
Appendix A. The Path Not Taken . . . . . . . . . . . . . . . . . 21 Appendix A. The Path Not Taken . . . . . . . . . . . . . . . . . 22
A.1. Initiating a new IKE SA . . . . . . . . . . . . . . . . . 21 A.1. Initiating a new IKE SA . . . . . . . . . . . . . . . . . 22
A.2. SIR . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 A.2. SIR . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
A.3. Birth Certificates . . . . . . . . . . . . . . . . . . . 22 A.3. Birth Certificates . . . . . . . . . . . . . . . . . . . 23
A.4. Reducing Liveness Check Length . . . . . . . . . . . . . 23 A.4. Reducing Liveness Check Length . . . . . . . . . . . . . 23
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 23 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 23
1. Introduction 1. Introduction
IKEv2, as described in [RFC5996] and its predecessor RFC 4306, has a IKEv2, as described in [RFC5996] and its predecessor RFC 4306, has a
method for recovering from a reboot of one peer. As long as traffic method for recovering from a reboot of one peer. As long as traffic
flows in both directions, the rebooted peer should re-establish the flows in both directions, the rebooted peer should re-establish the
tunnels immediately. However, in many cases the rebooted peer is a tunnels immediately. However, in many cases the rebooted peer is a
VPN gateway that protects only servers, so all traffic is inbound. VPN gateway that protects only servers, so all traffic is inbound.
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SHOULD be indistinguishable from random data. SHOULD be indistinguishable from random data.
o It should not be possible for an external attacker to guess the o It should not be possible for an external attacker to guess the
QCD token generated by an implementation. Cryptographic QCD token generated by an implementation. Cryptographic
mechanisms such as PRNG and hash functions are RECOMMENDED. mechanisms such as PRNG and hash functions are RECOMMENDED.
o The token maker MUST be able to re-generate or retrieve the token o The token maker MUST be able to re-generate or retrieve the token
based on the IKE SPIs even after it reboots. based on the IKE SPIs even after it reboots.
o The method of token generation MUST be such that a collision of o The method of token generation MUST be such that a collision of
QCD tokens between different pairs of IKE SPI will be highly QCD tokens between different pairs of IKE SPI will be highly
unlikely. unlikely.
For verification, the token taker makes a bitwise comparison of the
token stored along with the IKE SA with the token sent in the
unprotected message. Multihomed takers might flip back-and-forth
between several addresses, and have their tokens replaced as
described in Section 4.4. To help avoid the case where the latest
stored token does not match the address used after the maker lost
state, the token taker MAY store several earlier tokens associated
with the IKE SA, and silently discard the SA if any of them matches.
5.1. A Stateless Method of Token Generation 5.1. A Stateless Method of Token Generation
The following describes a stateless method of generating a token. In The following describes a stateless method of generating a token. In
this case, 'stateless' means not maintaining any per-tunnel state, this case, 'stateless' means not maintaining any per-tunnel state,
although there is a small amount of non-volatile storage required. although there is a small amount of non-volatile storage required.
o At installation or immediately after the first boot of the token o At installation or immediately after the first boot of the token
maker, 32 random octets are generated using a secure random number maker, 32 random octets are generated using a secure random number
generator or a PRNG. generator or a PRNG.
o Those 32 bytes, called the "QCD_SECRET", are stored in non- o Those 32 bytes, called the "QCD_SECRET", are stored in non-
volatile storage on the machine, and kept indefinitely. volatile storage on the machine, and kept indefinitely.
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TOKEN_SECRET_DATA = HASH(QCD_SECRET | SPI-I | SPI-R | IPaddr-T) TOKEN_SECRET_DATA = HASH(QCD_SECRET | SPI-I | SPI-R | IPaddr-T)
The IPaddr-T field specifies the IP address of the token taker. The IPaddr-T field specifies the IP address of the token taker.
Secret rollover considerations are similar to those in the previous Secret rollover considerations are similar to those in the previous
section. section.
Note that with a multi-homed token taker, the QCD token matches just Note that with a multi-homed token taker, the QCD token matches just
one of the token taker IP addresses. Usually this is not a problem, one of the token taker IP addresses. Usually this is not a problem,
as packets sent to the token maker come out the same IP address. If as packets sent to the token maker come out the same IP address. If
for some reason this changes, then the token maker can replace the for some reason this changes, then the token maker can replace the
token as described in section 4.4. token as described in section 4.4. If MOBIKE is used, replacing the
tokens SHOULD be piggybacked on the INFORMATIONAL exchange with the
UPDATE_SA_ADDRESSES notifications.
There is a corner case where the token taker begins using a different There is a corner case where the token taker begins using a new IP
IP address (because of multi-homing, roaming or normal network address (because of multi-homing, roaming or normal network
operations) and the token maker loses state before replacing the operations) and the token maker loses state before replacing the
token. In that case, it will send a correct QCD token, but the token token. In that case, it will send a correct QCD token, but the token
taker will still have the old token. In that case the extension will taker will still have the old token. In that case the extension will
not work, and the peers will revert to RFC 5996 recovery. not work, and the peers will revert to RFC 5996 recovery.
5.3. Token Lifetime 5.3. Token Lifetime
The token is associated with a single IKE SA, and SHOULD be deleted The token is associated with a single IKE SA, and SHOULD be deleted
by the token taker when the SA is deleted or expires. More formally, by the token taker when the SA is deleted or expires. More formally,
the token is associated with the pair (SPI-I, SPI-R). the token is associated with the pair (SPI-I, SPI-R).
6. Backup Gateways 6. Backup Gateways
Making crash detection and recovery quick is a worthy goal, but since Making crash detection and recovery quick is a worthy goal, but since
rebooting a gateway takes a non-zero amount of time, many rebooting a gateway takes a non-zero amount of time, many
implementations choose to have a stand-by gateway ready to take over implementations choose to have a stand-by gateway ready to take over
as soon as the primary gateway fails for any reason. [cluster] as soon as the primary gateway fails for any reason. [RFC6027]
describes considerations for such clusters of gateways with describes considerations for such clusters of gateways with
synchronized state, but the rest of this section is relevant even synchronized state, but the rest of this section is relevant even
when there is no synchronized state. when there is no synchronized state.
If such a configuration is available, it is RECOMMENDED that the If such a configuration is available, it is RECOMMENDED that the
stand-by gateway be able to generate the same token as the active stand-by gateway be able to generate the same token as the active
gateway. if the method described in Section 5.1 is used, this means gateway. if the method described in Section 5.1 is used, this means
that the QCD_SECRET field is identical in both gateways. This has that the QCD_SECRET field is identical in both gateways. This has
the effect of having the crash recovery available immediately. the effect of having the crash recovery available immediately.
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[RFC5996] Kaufman, C., Hoffman, P., Nir, Y., and P. Eronen, [RFC5996] Kaufman, C., Hoffman, P., Nir, Y., and P. Eronen,
"Internet Key Exchange Protocol: IKEv2", RFC 5996, "Internet Key Exchange Protocol: IKEv2", RFC 5996,
September 2010. September 2010.
13.2. Informative References 13.2. Informative References
[RFC5723] Sheffer, Y. and H. Tschofenig, "IKEv2 Session Resumption", [RFC5723] Sheffer, Y. and H. Tschofenig, "IKEv2 Session Resumption",
RFC 5723, January 2010. RFC 5723, January 2010.
[cluster] Nir, Y., Ed., "IPsec Cluster Problem Statement", [RFC6027] Nir, Y., Ed., "IPsec Cluster Problem Statement", RFC 6027,
draft-ietf-ipsecme-ipsec-ha (work in progress), July 2010. October 2010.
[recovery] [recovery]
Detienne, F., Sethi, P., and Y. Nir, "Safe IKE Recovery", Detienne, F., Sethi, P., and Y. Nir, "Safe IKE Recovery",
draft-detienne-ikev2-recovery (work in progress), draft-detienne-ikev2-recovery (work in progress),
January 2010. July 2009.
Appendix A. The Path Not Taken Appendix A. The Path Not Taken
A.1. Initiating a new IKE SA A.1. Initiating a new IKE SA
Instead of sending a QCD token, we could have the rebooted Instead of sending a QCD token, we could have the rebooted
implementation start an Initial exchange with the peer, including the implementation start an Initial exchange with the peer, including the
INITIAL_CONTACT notification. This would have the same effect, INITIAL_CONTACT notification. This would have the same effect,
instructing the peer to erase the old IKE SA, as well as establishing instructing the peer to erase the old IKE SA, as well as establishing
a new IKE SA with fewer rounds. a new IKE SA with fewer rounds.
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