Re: [saag] [tsvwg] Fwd: Last Call: <draft-ietf-tsvwg-transport-encrypt-19.txt> (Considerations around Transport Header Confidentiality, Network Operations, and the Evolution of Internet Transport Protocols) to Informational RFC

[Fernando Gont <[e-mail]>]

On 11/2/21 16:11, Tom Herbert wrote:
> On Thu, Feb 11, 2021 at 11:40 AM Fernando Gont <[e-mail]> wrote:
>>
>> On 11/2/21 15:18, Tom Herbert wrote:
>> [...]
>>>
>>> When the transport layer is encrypted, network devices would only see
>>> the plaintext EH and that is only what that is what they can act on.
>>> At the destination, we could try to rectify transport information in
>>> HBH with decrypted plaintext transport headers, but I suspect that
>>> wouldn't typically be done. The HBH information is only operationally
>>> useful to the network, not the transport endpoints that have access to
>>> the transport header.
>>
>> Then this is what an attacker would do:
>> He/she would advertise on a HBH option something that looks sensible to
>> the guy enforcing a network-based security policy, and then at transport
>> would do what he/she needs to do. :-)
>>
>>
>> e.g., HBH could advertise that my packets are directed to ports 80/443,
>> while in transport they are actually directed to port, say, 22.
>>
> It's more likely that information in the HBH would be generic and
> abstract, afterall the whole point of encrypting the transport header
> is to hide information from the network that it doesn't require, not
> to just blindly volunteer the same information somewhere else in the
> packet. Port numbers, for instance, are not required for delivery and
> in fact are prone to misinterpretation in the network (RFC7605)-- IMO
> it makes no sense to put those in a HBH option.
> 
> Regardless of HBH though, if the preponderence of transport headers
> are encrytped then network security policiy that relies on the
> information will need to change.

The folks running networks might as well argue that if you want your 
protocol to be successfully deployed (or at all deployed), your protocol 
might need to change.

It's a tussle. ANd I see valid arguments on both sides.

-- 
Fernando Gont
SI6 Networks
e-mail: [e-mail]
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