Fred:

That is one approach, but it seems like there needs to be a globally trusted 
trust anchor or set of trust anchors that understand the architecture to make 
sure that the certificates are providing the needed authentication and key 
management.

Russ

> On Jan 19, 2022, at 12:12 PM, Templin (US), Fred L 
> <[email protected]> wrote:
> 
> Russ, ICAO will be the top-level administrative authority for a hierarchy of
> Air Navigation Service Providers such as ARINC, SITA, Inmarsat and others.
> Different ANSPs will need to establish security peerings between neighboring
> ASBRs even though they are from different organizations. So, I assume this
> would mean that ICAO would need to be the ultimate authority for the
> common PKI?
> 
> Thanks - Fred
> 
>> -----Original Message-----
>> From: Russ Housley [mailto:[email protected]]
>> Sent: Wednesday, January 19, 2022 8:59 AM
>> To: Templin (US), Fred L <[email protected]>
>> Cc: IETF SecDir <[email protected]>; [email protected]; 
>> [email protected]
>> Subject: Re: Secdir early review of draft-ietf-rtgwg-atn-bgp-12
>> 
>> Fred:
>> 
>> If a tunnel that provides confidentiality and integrity is used for all 
>> control plane traffic, that addresses several of the comments.  This does
>> raise a question about the approach that will be used to provide keys for 
>> the tunnel.  Will ICAO or some delegated authority provide a PKI
>> for this purpose?
>> 
>> Russ
>> 
>> 
>>> On Jan 19, 2022, at 11:53 AM, Templin (US), Fred L 
>>> <[email protected]> wrote:
>>> 
>>> Russ, thank you for this Secdir review, and see below for responses:
>>> 
>>>> -----Original Message-----
>>>> From: rtgwg [mailto:[email protected]] On Behalf Of Russ Housley via 
>>>> Datatracker
>>>> Sent: Tuesday, January 18, 2022 2:22 PM
>>>> To: [email protected]
>>>> Cc: [email protected]; [email protected]
>>>> Subject: Secdir early review of draft-ietf-rtgwg-atn-bgp-12
>>>> 
>>>> Reviewer: Russ Housley
>>>> Review result: Has Issues
>>>> 
>>>> I reviewed this document as part of the Security Directorate's ongoing
>>>> effort to review all IETF documents being processed by the IESG.  These
>>>> comments were written primarily for the benefit of the Security Area
>>>> Directors.  Document authors, document editors, and WG chairs should
>>>> treat these comments just like any other IETF Last Call comments.
>>> 
>>> I will respond to your points below as IETF Last Call comments.
>>> 
>>>> Document: draft-ietf-rtgwg-atn-bgp-12
>>>> Reviewer: Russ Housley
>>>> Review Date: 2022-01-18
>>>> Early Review Due: 2022-02-11
>>>> IETF LC End Date: Unknown
>>>> IESG Telechat date: Unknown
>>>> 
>>>> 
>>>> Summary: Has Issues
>>>> 
>>>> 
>>>> Major Concerns:
>>>> 
>>>> Section 3 says:
>>>> 
>>>>  The only requirement is that ASNs
>>>>  must not be duplicated within the ATN/IPS routing system itself.
>>>> 
>>>> What party will administer these ASNs?  I understand why it does not
>>>> need to be IANA, but there does need to be a single authority, even
>>>> if a hierarchy is used to delegate assignments.  ASN collisions are
>>>> extremely harmful.
>>> 
>>> It is assumed that a centralized administrative authority for the ATN/IPS
>>> routing system overlay will be responsible for assigning the ASNs. As you
>>> note, this has nothing to do with IANA since the ATN/IPS routing system
>>> does  not interact with the Internet routing system, but most likely an
>>> entity such as the International Civil Aviation Organization (ICAO) will
>>> be responsible for overall administrative control. I gather from the point
>>> you are raising that you would appreciate some additional text to this
>>> effect, and I can certainly provide something more concrete.
>>> 
>>>> Section 10 says:
>>>> 
>>>>  BGP protocol message exchanges and control message exchanges used for
>>>>  route optimization must be secured to ensure the integrity of the
>>>>  system-wide routing information base.
>>>> 
>>>> I assume that "secured" means integrity protected.  BGP runs over TCP.
>>>> TCP-AO was defined primarily to provide integrity protection for BGP.
>>>> Is the intent to use TCP-AO or something else.  Please specify.
>>> 
>>> Security is based on network layer security between BGP peers, where all
>>> secured traffic between the peers is confidential, integrity-protected and
>>> authenticated by a security tunnel. Since the tunnel extends the entire
>>> length of the path between the BGP peers, I believe higher-layer security
>>> protection such as the TCP-AO you mention should be seen as optional.
>>> Again, if this satisfies the concern I could add some words to that effect.
>>> 
>>>> Minor Concerns:
>>>> 
>>>> Section 1 talks about IPsec and Wireguard as "secured encapsulations".
>>>> Please say what you mean by security here.  Are you expecting
>>>> confidentiality, integrity, or both?  Since this is an example,
>>>> please drop "Wireguard" or provide a reference for it.
>>> 
>>> I am expecting these network-layer securing functions to provide all of
>>> confidentiality, integrity and authorization. I can add words to make this
>>> more clear. About Wireguard, I would prefer to keep it and provide a
>>> reference, but if you recommend dropping I would be willing to do that.
>>> 
>>>> Section 1 goes on to say:
>>>> 
>>>>  In particular, tunneling must be used when
>>>>  neighboring ASBRs are separated by multiple INET hops.
>>>> 
>>>> This seems to mean that tunnels are not used in some if there is a
>>>> single INET hop.  Can you add a sentence about that?
>>> 
>>> Yes, actually this text is misleading to begin with because tunneling
>>> will be used even if the ASBRs are connected by a common link. I
>>> will look for better words to use here.
>>> 
>>>> Section 5 says: "...tunnels packets directly between Proxys ...".
>>>> Are these IPsec tunnels?  I am trying to fully understand when the
>>>> tunnels require IPsec (or some other security protocol) and when they
>>>> do not.
>>> 
>>> This is a good point. We want to establish an environment where security
>>> tunneling is used to protect only control messages and BGP protocol
>>> messages while unsecured tunneling is used to convey data plane packets
>>> when higher-layer security is used end-to-end. Again, more words may
>>> help clarify.
>>> 
>>>> Section 10 lists IPsec, TLS, WireGuard, etc.  This is the first
>>>> reference to TLS.  When do you see TLS being used?
>>> 
>>> TLS and possibly also DTLS may be used to protect the data plane in
>>> end-to-end security, but they do not really apply for protecting the
>>> control plane which is what this document is about. I could resolve
>>> this by either cutting TLS and remaining silent about data plane
>>> security, or including one or two sentences such as the above to
>>> explain the data plane considerations - do you have a preference?
>>> 
>>> Thanks - Fred
>>> 
>>> 
>>>> _______________________________________________
>>>> rtgwg mailing list
>>>> [email protected]
>>>> https://www.ietf.org/mailman/listinfo/rtgwg
>>> 
> 

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