[saag] Re: [nasr] Re: Re: Re: Re: NASR BOF Follo w-Up

I would agree with Ekr, here.

But I’d go further.

This is proof of configuration, not proof of function. That’s OK, but let’s call it for what it is.

 

A

 

From: Eric Rescorla <[email protected]> 
Sent: 29 May 2025 04:01
To: Liuchunchi(Peter) <[email protected]>
Cc: Luigi IANNONE <[email protected]>; Toerless Eckert <[email protected]>; nasr <[email protected]>; IETF SAAG <[email protected]>; Luigi Iannone <[email protected]>
Subject: [saag] Re: [nasr] Re: Re: Re: Re: NASR BOF Follow-Up

 

 

 

On Wed, May 28, 2025 at 7:32 PM Liuchunchi(Peter) <[email protected] <mailto:[email protected]> > wrote:

Okay I think there is some minor confusion here… 

 

1. The router in question would forward/has forwarded specific
traffic classes on specific links and not others.

[LI] Nope. NASR is not about forwarding on specific links. It is about being able to proof that traffic went through a certain set of devices that fulfil a set of claims (or requirements if you wish…).

2. That specific traffic classes would be/had been encrypted
using MACSEC.

[LI] Nope. (as I state in a previous mail) this is orthogonal to NASR. Whether you want to use it is not part of the NASR problem statement.

 

 

“A five tuple flow X use encrypted links“ IS a claim at device level. It is attestable by aggregating the evidences (configurations of all devices on path) and be inspected by the verifier. 

 

Well, that's precisely the question I think needs to be examined.

To take your example, suppose that we have elements A and B which have
an IPsec tunnel between them, and we want to know that all traffic
with a given 5-tuple will therefore be protected on that link. How do
we go about doing that by looking at the configuration directives?

The obvious place to start is by looking at the IPsec configuration to
see which traffic should be sent over the tunnel.

This is necessary but not sufficient. For instance, suppose that IPsec
is configured to use AH not ESP, so it's not encrypted? So, we need to
examine which IPsec modes are in use and which transport ciphers they
use.

Similarly, IKE might be configured with some kind of insecure key
establishment mode, so we need to look at the IKE key establishment
configuration. Further, we need to look at IKE authentication. Does it
use PKI or a shared key? Is that shared key actually being handled
securely, or is it a short password everyone knows?

This may well not be an exhaustive list, because I haven't thought
about all the ways things can be misconfigured, even for a
comparatively trivial property like this.

-Ekr





 

 

 

From: Meiling Chen <[email protected] <mailto:[email protected]> > 
Sent: Thursday, May 29, 2025 9:27 AM
To: Luigi IANNONE <[email protected] <mailto:[email protected]> >; Eric Rescorla <[email protected] <mailto:[email protected]> >
Cc: Toerless Eckert <[email protected] <mailto:[email protected]> >; nasr <[email protected] <mailto:[email protected]> >; IETF SAAG <[email protected] <mailto:[email protected]> >; Luigi Iannone <[email protected] <mailto:[email protected]> >
Subject: [saag] Re: [nasr] Re: Re: Re: Re: NASR BOF Follow-Up

 

Hi,

 

I think Luigi's reply is completely in line with the original intention.

 

Best,

Meiling

 

 

发件人:  <mailto:[email protected]> Luigi IANNONE

时间: 2025/05/27(星期二)15:46

收件人:  <mailto:[email protected]> Eric Rescorla; <mailto:[email protected]> Meiling Chen;

抄送人:  <mailto:[email protected]> Watson Ladd; <mailto:[email protected]> Henk Birkholz; <mailto:[email protected]> Liuchunchi; <mailto:[email protected]> Toerless Eckert; <mailto:[email protected]> nasr; <mailto:[email protected]> IETF SAAG; <mailto:[email protected]> Luigi Iannone;

主题: RE: Re: [nasr] Re: [saag] Re: Re: Re: NASR BOF Follow-Up

HI,

 

I think there is a bit of a  misunderstanding … 

 


The BOF presented a number of problems that allegedly NASR was trying
to solve, including that:

1. The router in question would forward/has forwarded specific
traffic classes on specific links and not others.

[LI] Nope. NASR is not about forwarding on specific links. It is about being able to proof that traffic went through a certain set of devices that fulfil a set of claims (or requirements if you wish…).

Attesting that the set of devices fulfils the requirements is done by extending the RATS technology. 

Proving that the traffic did go through those devices is done a proof of transit technology for which there are a couple of early ideas documented. 


2. That specific traffic classes would be/had been encrypted
using MACSEC.

[LI] Nope. (as I state in a previous mail) this is orthogonal to NASR. Whether you want to use it is not part of the NASR problem statement.

NASR represents one specific proposal for addressing these problems,
which is to attest to the code and configuration running on specific
network elements. So, yes, a system like NASR needs to establish
that the code and configuration guarantees these properties in
order to address the stated problem. 

[LI] You do not need that level of granularity. 

It's certainly not sufficient
to demonstrate that the device simply supports MACSEC, because
it might be disabled.

If you think there is some other set of problems that need to be
solved, and that these don't need to be then I think you need to state
that more clearly.

[LI] Agreed. We certainly need to do more work in clarifying the problem and possible solution space.

The ongoing exchange in very helpful in this sense.

Thanks

Ciao

L. 

 



-Ekr

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