MIPv6 CN-Targeted Location Privacy and Optimized Routing draft-weniger-mobopts-mip6-cnlocpriv-01 <[e-mail]>

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MIPv6 CN-Targeted Location Privacy and Optimized
Routing draft-weniger-mobopts-mip6-cnlocpriv-01
ltkilian.weniger_at_eu.panasonic.comgt
IETF 68, Prague, March 2007
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Outline

• Scope of this draft
• Scenario and problem definition
• Solution in draft-irtf-mobopts-location-privacy-so
  lutions
• Proposed solution
• Changes in new draft version
• Conclusion

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Scope of this draft

• CN-targeted location privacy Preventing
  disclosure of the MNs topological location to a
  Correspondent Node (CN)
• CN can be off-path attacker initiating a session
  just to find out MNs location
• Problem of disclosing location to eavesdroppers
  is out of scope

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Scenario

• MN is reachable at public HoAIR
• associated with MNs identity (e.g., FQDN) and is
  anchored at HAIR
• Session can be initiated either by MN or CN
• CN initiates session by sending data to HoAIR
• Communication session requires short packet
  delays
• MN wants to hide its location from CN
• i.e., ltidentity, locationgt must be hidden from CN

HAIR
CN
MN

• MN addresses
• HoAIR
• CoA

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Problem definition

• A MIPv6 MN has the choice. It can either
• hide location from CN (by using rev. tunneling)
  or
• get short packet delays (by using RO mode)
• How to achieve both simultaneously?

HAIR
1. HoAIR revealed
reverse tunneling
CN
MN
RO mode
2. ltHoAIR, CoAgt revealed

• MN addresses
• HoAIR
• CoA

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Solution in draft-irtf-mobopts-location-privacy-so
lutions

• Approach
• Disclose location, but hide identity by using
  pseudo HoA
• MN-initiated session (case 1)
• MN uses RO mode with HoApseudo as HoA
• ?Issue location privacy compromised if CN
  figures out MNs identity during session
• CN-initiated session (case 2)
• Since CN initiated session using HoAIR, it
  already knows MNs identity
• ?Issue no solution to the problem

HAIR
CN
MN
2. ltHoAIR, CoAgt revealed

• MN addresses
• HoAIR
• HoApseudo
• CoA

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Proposed solution

• Approach
• Hide location, disclose identity by bootstrapping
  with HA close to CN
• MN-initiated session (case 1)
• MN uses reverse tunneling mode with HoAOR as HoA
• ?location privacy ensured
• CN-initiated session (case 2)
• MN uses RO mode with HoAIR as HoA and HoAOR as
  CoA
• CoT/i,BU,data is tunneled over HAOR
• ?location privacy ensured

HAIR
1. HoAOR revealed
HAOR
CN
reverse tunneling
MN
(RO mode)
2. ltHoAIR, HoAORgt revealed

• MN addresses
• HoAIR
• HoAOR
• CoA

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Changes in new draft version (based on feedback
from last meeting)

• HAOR must be trusted, since it learns MNs
  location
• Either MN verifies trust before or during the
  bootstrapping or HAOR discovery mechanism only
  returns trusted home agents
• Assumptions about deployed HAOR
• HAOR is not required to be located in CNs
  domain. A nearby domain is sufficient
• (Local) HAs deployed by ASPs could be used as
  HAOR
• Assumptions about roaming relationships
• This draft assumes that MNs MSA has roaming
  relationships with multiple MSPs offering HA
  services from various locations
• This is also required for widespread use of local
  HA service (MSPASP) as specified, e.g., in
  draft-ietf-mip6-bootstrapping-integrated-dhc

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Conclusion

• draft-irtf-mobopts-location-privacy-solutions-04
  lists solutions for MIPv6 location privacy
  problems, but support for scenarios where MN
  needs both location hiding from CN and optimized
  routing is missing
• Bootstrapping with a HA close to CN is an option
  to achieve that with existing MIPv6 tools and
  without changes to HA, CN or MIPv6 protocol msgs

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Thanks!

• Questions/Comments?

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Appendix
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HAOR discovery

• Specification of discovery mechanism is currently
  out of scope
• Some options are
• MN has list of MSPs (possibly with distances to
  various prefixes), which can be used by MN to
  select HAOR
• Anycast-based or DNS-based HA address discovery
  (according to draft-ietf-mip6-bootstrapping-split
  )
• MN contructs anycast address based on CNs prefix
  
• MN include CNs prefix or FQDN in QNAME, e.g.,
  _mip6._ipv6.CNdomain or CNdomain.nearbyHA.MNdom
  ain
• DHCP-based HA address discovery (according to
  draft-ietf-mip6-bootstrapping-integrated-dhc,
  draft-ietf-mip6-hiopt)
• MN puts CNs realm as target network in Home
  Network Identifier Option

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Case 1 MN-initiated session

• Before sending data to CN, MN discovers HAOR
• MN bootstraps with HAOR and obtains HoAOR
• MN uses HAOR in bi-directional tunneling mode and
  HoAOR for the session with CN
• MN keeps registrations with other HAs, such as
  HAIR

MN
CN
HAOR
HAOR discovery
Decision to optimize route
MIP bootstrapping (incl. obtaining HoAOR)
BU (HoAOR, CoA)
Data packets
Session starts(sending from HoAOR)
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Case 2 CN-initiated session

• Data is sent to/from MNs public HoAIR
• MN discovers HAOR and bootstrap with it
• MN performs return routability over reverse
  tunnel to HAOR and registers HoAOR as CoA at CN

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Headers in case 2 (CN-initiated sessions)

• Data packets and BU sent by MN to CN
• IPv6 header (source care-of address,
• destination HAOR)
• ESP header in tunnel mode
• IPv6 header (source HoAOR,
• destination correspondent
  node)
• Destination Options header
• Home Address option (HoAIR)
• Any protocol
• CoTi sent by MN to CN
• IPv6 header (source care-of address,
• destination HAOR)
• ESP header in tunnel mode
• IPv6 header (source HoAOR,
• destination correspondent
  node)
• Any protocol

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Possible solution with local HA

• Approach
• Disclose location and identity, but hide fact
  that HoAlocal contains location information
• Case 1 MN-initiated session
• MN bootstraps with local HAlocal and uses reverse
  tunneling mode
• ? Issue location privacy is compromised if CN
  knows identiy associated with HAlocal and knows
  that HoAlocal is anchored at local HA
• Case 2 CN-initiated session
• To be reachable, MN publishes ltHoAlocal,
  identitygt
• ? Issue location privacy is compromised if CN
  knows that HoAlocal is anchored at local HA

HAIR
1. HoAlocal revealed
HAlocal / IR
reverse tunneling
CN
MN
2. ltHoAlocal, identitygt revealed

• MN addresses
• HoAlocal
• CoA