Re: [OAUTH-WG] TLS version requirements in OAuth 2.0 base

[Stephen Farrell <[e-mail]>]

On 12/01/2011 08:10 PM, Peter Saint-Andre wrote:
> On 12/1/11 1:09 PM, Rob Richards wrote:
>> On 11/28/11 10:39 PM, Barry Leiba wrote:
>>>> The OAuth base doc refers in two places to TLS versions (with the same
>>>> text in both places:
>>>>
>>>> OLD
>>>> The authorization server MUST support TLS 1.0 ([RFC2246]), SHOULD
>>>> support TLS 1.2 ([RFC5246]) and its future replacements, and MAY
>>>> support additional transport-layer mechanisms meeting its security
>>>> requirements.
>>>>
>>>> In both the shepherd review and the AD review, this was called into
>>>> question:
>>>> 1. MUST for an old version and SHOULD for the current version seems
>>>> wrong.
>>>> 2. Having specific versions required locks us into those versions (for
>>>> example, all implementations will have to support TLS 1.0, even long
>>>> after it becomes obsolete, unless we rev the spec.
>>> The comments I've gotten on this show a clear consensus against the
>>> change I suggest, and against any attempt to require a version of TLS
>>> other than 1.0.  I still, though, am concerned that locking this spec
>>> into TLS 1.0 is limiting.  So let me propose an alternative wording,
>>> which again tries to make the version(s) non-normative, while making
>>> it clear which version(s) need to be implemented to get
>>> interoperability:
>>>
>>> NEW
>>> --------------------------------------------
>>> The authorization server MUST implement TLS.  Which version(s)
>>> ought to be implemented will vary over time, and depend on
>>> the widespread deployment and known security vulnerabilities at
>>> the time of implementation.  At the time of this writing, TLS version
>>> 1.2 [RFC5246] is the most recent version, but has very limited
>>> actual deployment, and might not be readily available in
>>> implementation toolkits.  TLS version 1.0 [RFC2246] is the
>>> most widely deployed version, and will give the broadest
>>> interoperability.
>>>
>>> Servers MAY also implement additional transport-layer
>>> mechanisms that meet their security requirements.
>>> --------------------------------------------
>>>
>>> Comments on this version?
>>>
>>> Barry
>>>
>>
>> Text is neutral enough for me as it's not mandating anything that isn't
>> readily available. Only comment is whether or not there is a need to
>> even talk about the specific versions or if just the following is enough:
>>
>> The authorization server MUST implement TLS. Which version(s) ought to
>> be implemented will vary over time, and depend on the widespread
>> deployment and known security vulnerabilities at the time of
>> implementation.
>>
>> Servers MAY also implement additional transport-layer mechanisms that
>> meet their security requirements.
>
> That seems fine to me.

FWIW, I think I'd prefer Barry's as Rob's would be more likely
to generate discusses and we do know that there are some security
advantages to TLS 1.2 vs. 1.0. (BTW, has anyone considered how
or if the BEAST attack might affect oauth? Be good to know if
someone's done that analysis.)

However, as AD, I could live with either, since lots of other
specs just say TLS. (But you need to point to the latest RFC as
normative or that will I bet generate discusses.)

Cheers,
S.


> Peter
>