[Openid-specs-ab] Single Sign-On is dead on iOS 11

Thu Aug 24 17:07:22 UTC 2017

Hmmm. Not so good...

On Wed, Aug 23, 2017 at 4:38 PM matake, nov via Openid-specs-ab <
openid-specs-ab at lists.openid.net> wrote:

> Hi,
>
> FYI:
> I've confirmed iOS11's Intelligent Tracking Prevention treated IdP domain
> as "having tracking capability" and didn't send IdP cookie in iframe after
> 24h.
> So that prompt=none w/ hidden iframe only works within 24 hours since last
> login action at IdP.
>
> I'm still not unsure about the local storage behaviour though.
>
> 2017-06-14 6:57 GMT+09:00 Iain McGinniss via Openid-specs-ab <
> openid-specs-ab at lists.openid.net>:
>
>> Each SFSafariViewController (SFSVC) instance is essentially a new
>> browser, with the following consequences:
>>
>> 1. If the user signs in to the OP in Safari, this signed in state is not
>> visible from any SFSVC instance.
>> 2. If the user signs in via an SFSVC, this signed in state also cannot be
>> synchronized to Safari.
>>
>> As a result, there's no shared OP session between any apps; the user must
>> re-authenticate with the OP within every app that uses it.
>>
>> Furthermore, the Intelligent Tracking Prevention
>> <https://webkit.org/blog/7675/intelligent-tracking-prevention/> *may* flag
>> the OP domain as a capable of tracking the user, at which point any cookie
>> / local storage state associated with that domain is "redacted" if the user
>> has not interacted with the OP domain in the last 24 hours. "Interaction"
>> here specifically means loading a top-level page on that domain and
>> clicking on something. It seems highly likely that *.google.com is going
>> to be marked as a tracking domain in Safari.
>>
>> So, if you do anything in iframes with your OP domains (we do at Google),
>> your cookies are going to appear and disappear in a very unpredictable way.
>> Session state is going to become very unreliable.
>>
>> I plan to give an impromptu short talk on these changes at CIS.
>>
>> Iain
>>
>> On Tue, Jun 13, 2017 at 2:40 PM, rich levinson via Openid-specs-ab <
>> openid-specs-ab at lists.openid.net> wrote:
>>
>>> Hi Nat, et al,
>>>
>>> I am not sure I understand why this situation should cause anything to
>>> "break".
>>>
>>> Let me explain my view of this situation, in the context of general
>>> session mgmt,
>>> which is the following:
>>>
>>> In the "OpenID Connect Session Management 1.0" spec:
>>>     http://openid.net/specs/openid-connect-session-1_0.html
>>>  it says:
>>>
>>> "In OpenID Connect, the session at the RP typically starts
>>>  when the RP validates the End-User's ID Token.
>>>   ...
>>> When the OP supports session management, it MUST also return the Session State
>>>  as an additional session_state parameter in the Authentication Response.
>>>   ...
>>> This parameter is:
>>>     session_state
>>>      Session State.
>>>      JSON [RFC7159] string that represents the End-User's login state at the OP.
>>>      It MUST NOT contain the space (" ") character.
>>>      This value is opaque to the RP.
>>>      This is REQUIRED if session management is supported.
>>>
>>> The Session State value is initially calculated on the server."
>>>
>>> This indicates that the OP has knowledge of the End-User's login state
>>> at the OP.
>>> However, this login state is independent of the "session at the RP",
>>> which is
>>> created when the client app (RP) rcv's the identity token which, in the
>>> protocol,
>>> is well after the End-User logged in at the OP.
>>>
>>> Later in the spec, section 5, it is also stated that:
>>>
>>> "5.  RP-Initiated Logout
>>> An RP can notify the OP that the End-User has logged out of the site and
>>>  might want to log out of the OP as well.
>>> In this case, the RP, after having logged the End-User out of the RP,
>>>  redirects the End-User's User Agent to the OP's logout endpoint URL.
>>> This URL is normally obtained via the end_session_endpoint element
>>>  of the OP's Discovery response or may be learned via other mechanisms."
>>>
>>> This basically confirms the supposition above that the OP login and the
>>> RP session are
>>> effectively independent entities.
>>>
>>> Now, let's consider the case where a 2nd RP decides to start a session w
>>> the same End-User,
>>> presumably, a 2nd RP on the same device where the 1st RP established a
>>> session.
>>>
>>> When the 2nd RP sends the Authentication Request to the OP's /authorize
>>> endpoint,
>>> it seems obvious to me that the OP knows the End-User is logged in and
>>> would have
>>> no problem issuing a 2nd id-token to the 2nd RP, w/o re-logging in the
>>> End-User.
>>>
>>> Assuming this is the case, then I do not understand why ios-11, by
>>> "siloing" the apps
>>> prevents the OP from issuing new id-tokens to each app, all under the
>>> original
>>> OP-login by the End-User.
>>>
>>> Am I missing something?
>>>
>>>   Thanks,
>>>   Rich
>>>
>>>
>>>
>>>
>>> On 6/12/2017 8:04 PM, Nat Sakimura via Openid-specs-ab wrote:
>>>
>>> Maybe we can call upon the privacy community as well raising the voice
>>> that this is very bad for privacy.
>>> I wonder what is the privacy enhancement they have in mind.
>>>
>>> On Fri, Jun 9, 2017 at 2:34 AM 'Iain McGinniss' via OIDF Account Chooser
>>> list <oidf-account-chooser-list at googlegroups.com> wrote:
>>>
>>>> Hello all,
>>>>
>>>> Just to bring this to your attention: Apple has essentially killed
>>>> single sign-on for native apps in iOS 11. Changes made to
>>>> SFSafariViewController (used by AppAuth, and the recommended mechanism for
>>>> federated login by Apple) now mean that browser state is partitioned per
>>>> app, so there is no way for an existing authentication in the browser to be
>>>> reused by an app.
>>>>
>>>> This fundamentally breaks an important part of OpenID Connect - users
>>>> will now need to re-authenticate with their IDP in every app that they use.
>>>> There is still time to provide feedback to Apple on this change, though
>>>> they have been discussing this change in terms of "enhancing privacy" and
>>>> I'd be very surprised if they change tack now.
>>>>
>>>> Iain
>>>> --
>>>>
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>>>> .
>>>>
>>> --
>>>
>>> Nat Sakimura
>>>
>>> Chairman of the Board, OpenID Foundation
>>>
>>>
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-- 

Nat Sakimura

Chairman of the Board, OpenID Foundation
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