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

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

A confidential client, as per the `web application` definition in Section
`2.1.  Client Types`.

On Thu, Mar 12, 2020 at 4:39 PM Torsten Lodderstedt <[e-mail]>
wrote:

> Is that a public client?
>
> Am 12.03.2020 um 20:32 schrieb 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
>>>>
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