Re: [tram] Artart telechat review of draft-ietf-tram-stunbis-16

[Peter Saint-Andre <[e-mail]>]

On 4/17/18 4:02 AM, Marc Petit-Huguenin wrote:
> 
> On 04/16/2018 08:12 PM, Eric Rescorla wrote:
>> On Mon, Apr 16, 2018 at 5:22 PM, Peter Saint-Andre <[e-mail]>
>> wrote:
>>
>>> Hi Marc, a few further comments inline.
>>>
>>> On 4/16/18 5:43 PM, Marc Petit-Huguenin wrote:
>>>> Hi Peter,
>>>>
>>>> Thanks for the review and sorry for the delay in responding, I was
>>> traveling for the last 4 weeks.
>>>>
>>>> See my responses inline.
>>>>
>>>> On 04/02/2018 03:59 PM, Peter Saint-Andre wrote:
>>>>> Reviewer: Peter Saint-Andre
>>>>> Review result: Ready with Nits
>>>>>
>>>
>>> <snip/>
>>>
>>>>> The first paragaraph of Section 6.2.3 restates recommendations from RFC
>>>>> 7525; why not simply reference that specification?
>>>>
>>>> The original text in RFC5389 said this:
>>>>
>>>> " When STUN is run by itself over TLS-over-TCP, the
>>>>   TLS_RSA_WITH_AES_128_CBC_SHA ciphersuite MUST be implemented at a
>>>>   minimum. [...]"
>>>>
>>>> The new text is an attempt at updating it in the same spirit of giving
>>> minimal instructions and complementing them with a reference to RFC 7525 -
>>> which was the reason for the reference to RFC 7525 there.
>>>>
>>>> So I kept the text there, followed by the following paragraph, in
>>> addition of moving the original last paragraph in the Security
>>> Consideration section:
>>>>
>>>> " These recommendations are just a part of the the recommendations in
>>>>   [RFC7525] that implementations and deployments of a STUN usage using
>>>>   TLS or DTLS SHOULD follow."
>>>
>>> I would instead suggest that we do something like Section 2 of RFC 7590
>>> for XMPP:
>>>
>>>    The best current practices documented in the "Recommendations for
>>>    Secure Use of TLS and DTLS" [RFC7525] are included here by reference.
>>>    Instead of repeating those recommendations here, this document mostly
>>>    provides supplementary information regarding secure implementation
>>>    and deployment of XMPP technologies.
>>>
>>> Here's the rationale: RFC 7525 is likely to be updated/replaced more
>>> quickly than STUNbis. If STUNbis recommends a particular cipher suite
>>> that 7525bis stops recommending, in the absence of STUNter will STUN
>>> implementations keep following STUNbis or will they upgrade to whatever
>>> 7525bis recommends? I suggest it will be the former, which is not what
>>> we want.
>>>
>>
>> I forgot about this in my review, but you should also profile ciphers for
>> TLS 1.3.
>>
>> -Ekr
>>
> 
> Do you have any suggestion for these, or a pointer to a document that I can use to find these?

Off-topic: it sounds like we might need to start work on 7525bis...

Peter