Re: [OAUTH-WG] First Draft of OAuth 2.1

[Pedro Igor Silva <[e-mail]>]

I agree with you and recently, we had to deal with an issue where a `web
application` using rotation (as defined by the draft) was having issues to
refresh tokens due to multiple concurrent requests at the moment a token is
about to expire or already expired. We had to add some controls to deal
with concurrency and additional complexity + performance penalties. And for
such clients, I was not sure whether or not rotation makes sense.

On Thu, Mar 12, 2020 at 4:05 PM Vittorio Bertocci <Vittorio=
[e-mail]> wrote:

> Thanks for the clarification, Torsten.
> I believe it's the first time I see use of client credentials positioned
> as sender constraint; if the intent is saying that confidential clients
> should use their credentials when redeeming refresh tokens, I am of course
> in agreement but I think the language should be clearer and state the above
> explicitly.
>
> Re: failure frequency, I know of scenarios were the designers added
> rotation by default, and after a while it was turned to opt in because of
> the frequency of errors and impact on user experience/call center.
> I really believe that putting this as a MUST is justified only for
> exceedingly vulnerable situations, like SPAs.
> Native/desktop clients should be free to decide whether they want to opt
> in without loosing compliance. Just my 2 C
>
> On Thu, Mar 12, 2020 at 11:58 AM Torsten Lodderstedt <torsten=
> [e-mail]> wrote:
>
>> Hi,
>>
>> sender constraining refresh tokens for confidential client means client
>> authentication + check the binding of the refresh token with the respective
>> client id. I don’t think this is new as RFC6759 already required ASs to
>> check this binding. Assuming backends are generally confidential clients
>> also means no rotation and no cache synchronization needed.
>>
>> Rotation should be used for frontends, e.g. native apps and only if there
>> is there no other option. If a refresh fails, the app must go through the
>> authorization process again. That’s inconvenient so the question is how
>> often this happens. What I can say, I have never seen customer complaining
>> in several years of operation of ASs with refresh token rotation (including
>> replay detection) for native apps with millions of users.
>>
>> best regards,
>> Torsten.
>>
>> Am 12.03..2020 um 19:24 schrieb Vittorio Bertocci <Vittorio=
>> [e-mail]>:
>>
>> 
>> Hey guys,
>> thanks for putting this together.
>> I am concerned with the real world impact of imposing sender constraint |
>> rotation as a MUST on refresh tokens in every scenario.
>> Sender constraint isn't immediately actionable - we just had the
>> discussion for dPOP, hence I won't go in the details here.
>> Rotation isn't something that can be added without significant impact on
>> development and runtime experiences:
>>
>>    - on distributed scenarios, it introduces the need to serialize
>>    access to shared caches
>>    - network failures can lead to impact on experience- stranding
>>    clients which fail to receive RTn+1 during RTn redemption in a limbo where
>>    user interaction might become necessary, disrupting experience or
>>    functionality for scenarios where the user isn't available to respond.
>>    -
>>
>>
>>
>> On Wed, Mar 11, 2020 at 5:28 PM Aaron Parecki <aaron@parecki..com
>> <[e-mail]>> wrote:
>>
>>> I'm happy to share that Dick and Torsten and I have published a first
>>> draft of OAuth 2.1. We've taken the feedback from the discussions on
>>> the list and incorporated that into the draft.
>>>
>>> https://tools.ietf.org/html/draft-parecki-oauth-v2-1-01
>>>
>>> A summary of the differences between this draft and OAuth 2.0 can be
>>> found in section 12, and I've copied them here below.
>>>
>>> > This draft consolidates the functionality in OAuth 2.0 (RFC6749),
>>> > OAuth 2.0 for Native Apps (RFC8252), Proof Key for Code Exchange
>>> > (RFC7636), OAuth 2.0 for Browser-Based Apps
>>> > (I-D.ietf-oauth-browser-based-apps), OAuth Security Best Current
>>> > Practice (I-D.ietf-oauth-security-topics), and Bearer Token Usage
>>> > (RFC6750).
>>> >
>>> >   Where a later draft updates or obsoletes functionality found in the
>>> >   original [RFC6749], that functionality in this draft is updated with
>>> >   the normative changes described in a later draft, or removed
>>> >   entirely.
>>> >
>>> >   A non-normative list of changes from OAuth 2.0 is listed below:
>>> >
>>> >   *  The authorization code grant is extended with the functionality
>>> >      from PKCE ([RFC7636]) such that the only method of using the
>>> >      authorization code grant according to this specification requires
>>> >      the addition of the PKCE mechanism
>>> >
>>> >   *  Redirect URIs must be compared using exact string matching as per
>>> >      Section 4.1.3 of [I-D.ietf-oauth-security-topics]
>>> >
>>> >   *  The Implicit grant ("response_type=token") is omitted from this
>>> >      specification as per Section 2.1.2 of
>>> >      [I-D.ietf-oauth-security-topics]
>>> >
>>> >   *  The Resource Owner Password Credentials grant is omitted from this
>>> >      specification as per Section 2.4 of
>>> >      [I-D.ietf-oauth-security-topics]
>>> >
>>> >   *  Bearer token usage omits the use of bearer tokens in the query
>>> >      string of URIs as per Section 4.3.2 of
>>> >      [I-D.ietf-oauth-security-topics]
>>> >
>>> >   *  Refresh tokens must either be sender-constrained or one-time use
>>> >      as per Section 4.12.2 of [I-D.ietf-oauth-security-topics]
>>>
>>> https://tools.ietf.org/html/draft-parecki-oauth-v2-1-01#section-12
>>>
>>> I'm excited for the direction this is taking, and it has been a
>>> pleasure working with Dick and Torsten on this so far. My hope is that
>>> this first draft can serve as a good starting point for our future
>>> discussions!
>>>
>>> ----
>>> Aaron Parecki
>>> aaronparecki.com
>>> @aaronpk
>>>
>>> P.S. This notice was also posted at
>>> https://aaronparecki.com/2020/03/11/14/oauth-2-1
>>>
>>> _______________________________________________
>>> OAuth mailing list
>>> [e-mail]
>>> https://www.ietf.org/mailman/listinfo/oauth
>>>
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