[Openid-specs-ab] Session management and third party cookies

Nat Sakimura sakimura at gmail.com
Tue Aug 21 00:28:37 UTC 2012

For the session management purpose, we really do not need to track. We just
need to tell the client the state change. It is the other direction than

The browser does not need to send anything to the server but pull the state
efficiently. Local storage is ideal if it err not governed by the same
policy as cookies.

=nat via iPhone

On Aug 21, 2012, at 5:40 AM, Torsten Lodderstedt <torsten at lodderstedt.net>

 Internet Explorer seems to behave quite similar to Safari. It allows the
iframe to read but not to write a cookie after this cookie had been set by
a top level window.

Are we facing a real show stopper here? In my opinion, the session
management design might collide with all kinds of tracking countermeasures
implemented by the browser vendors. It might not be the default today but
as people get more sensible about this topic this might change.


Am 18.08.2012 18:36, schrieb Nat Sakimura:

It seems there are philosophical differences. Chrome seems to have the
philosphy that when Blocking them, they rearly have to be blocked
completely, perhas because if it could be read, it can be sent over to rhe
server via a script. Firefox seems to be moving towards that direction,

 On the surface, it looks privacy enhancing. However, in reality, it is not
IMHO. Blocking even the read of the third party local storage makes it very
hard for the users to use the web in that mode resulting in less people
actually setting that option. This means less privacy protection. True, you
can set the exception regex in the setting but that is way too geeky.

 So, I think Apple's policy is more sensible. But others may have different

=nat via iPhone

On Aug 19, 2012, at 12:45 AM, Torsten Lodderstedt <torsten at lodderstedt.net>

Am 16.08.2012 22:21, schrieb Nat Sakimura:

Actually, Safari should not be a problem because the cookie is first
created at the top level window when the user first logged in to the IdP.
Safari allows the read of the cookie in iFrame, though it does not allow
write. This is perfectly fine.

 The problem is in other browsers. Chrome after rel. 17, when the user sets
no third party cookie / local storage option, it even blocks the reading of
the cookie. The same behavior was reported on Firefox as well. Since they
are not the default setting, not many people perhaps are affected, yet it
is a valid concern.

Do you consider this a bug or is there a concept/philosophy behind?



On Fri, Aug 17, 2012 at 2:25 AM, Torsten Lodderstedt <
torsten at lodderstedt.net> wrote:

> Hi all,
> according to one of our develpers, at least Safari is blocking such
> cookies only if they were not created as a result of some user interaction,
> e.g. a form post.
> regards,
> Torsten.
> Am 14.08.2012 14:37, schrieb John Bradley:
>  So I take it that this is not about blocking what we would think of as a
>> normal 3rd party cookie.
>> The Browsers are also trying to block sneaky ways that people are using
>> to get around 3rd party cookie blocking.
>> We are getting caught in that basket because the IdP iframe is invoked
>> from the RP iframe.
>> Any Ideas?
>> On 2012-08-14, at 7:22 AM, Nat Sakimura wrote:
>>  Latest Safari on iOS 5.1.1 and Mountain Lion.
>>> =nat via iPhone
>>> On Aug 14, 2012, at 9:11 PM, Chuck Mortimore <cmortimore at salesforce.com>
>>> wrote:
>>>  Latest versions of Safari just got far more aggressive about this, so
>>>> I'd report what version of Safari you were on.
>>>> -cmort
>>>> On Aug 13, 2012, at 6:36 PM, Nat Sakimura wrote:
>>>>  I did a little bit of checking on the relationships between the
>>>>> Session management spec and third party cookies.
>>>>> In short, it varies.
>>>>> In Safari and older Chrome, it works.
>>>>> In Chrome after v.17(?), if the user sets the block third party
>>>>> cookies option, it does not.
>>>>> I have not tested IE.
>>>>> Nat Sakimura
>>>>> _______________________________________________
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Nat Sakimura (=nat)
Chairman, OpenID Foundation
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