[Openid-specs-ab] Transient Client Secret Extension for OAuth

Torsten Lodderstedt torsten at lodderstedt.net
Mon Jul 29 08:18:35 UTC 2013


 

Based on our experiences I would state, this data is the same across
apps as this is server meta data. 

Am 29.07.2013 10:13, schrieb Anthony
Nadalin: 

> A single authorization server can support thousands of
apps, so a config file is very problematic if not per app and per app is
very data intensive. The other point is exposing information gives
attack points and to prevent those we have to get into authorization and
seems we would repeat all the xri/xrd 
> 
> FROM: Torsten Lodderstedt
[mailto:torsten at lodderstedt.net] 
> SENT: Monday, July 29, 2013 1:08
AM
> TO: Anthony Nadalin
> CC: openid-specs-ab at lists.openid.net
>
SUBJECT: RE: [Openid-specs-ab] Transient Client Secret Extension for
OAuth 
> 
> Can you give an example? 
> 
> Am 29.07.2013 10:03, schrieb
Anthony Nadalin: 
> 
>> I think this gets us in a bind with information
exposure, as this all can be very app dependent and not authorization
server general 
>> 
>> FROM: openid-specs-ab-bounces at lists.openid.net
[mailto:openid-specs-ab-bounces at lists.openid.net] ON BEHALF OF Torsten
Lodderstedt
>> SENT: Monday, July 29, 2013 12:58 AM
>> TO:
openid-specs-ab at lists.openid.net
>> SUBJECT: Re: [Openid-specs-ab]
Transient Client Secret Extension for OAuth 
>> 
>> Hi all, 
>> 
>> I
think OAuth authorization servers need a way to announce their
capabilities (e.g. grant types, dyn client reg, revocation, support for
tcse :-)) and respective endpoints. Using a config file at a well-known
location 
>> 
>> /.well-known/oauth-configuration
>> 
>> seems
straightforward. For authorization servers, which are also OIDC OPs, the
same (or a different) file might be exposed at 
>> 
>>
/.well-known/openid-configuration. 
>> 
>> Thoughts? 
>> 
>> regards,
>>
Torsten. 
>> 
>> Am 29.07.2013 09:45, schrieb Nat Sakimura: 
>> 
>>>
Hmmm. Then, the client has lost its capability to find out whether the
server is secure or not dynamically. 
>>> 
>>> Do you mean that the
client should find it out out-of-band? 
>>> 
>>> That's possible, and is
more OAuthy. 
>>> 
>>> So, instead of current 3.2, it can just state :

>>> 
>>> The client MUST find out if the server supports this mode
before issuing the authorizaiton request. The exact method of how it can
be done is out of scope. 
>>> 
>>> Is that what you mean? 
>>> 
>>> Nat

>>> 
>>> 2013/7/29 Brian Campbell <bcampbell at pingidentity.com> 
>>>

>>>> Pretty much just removing 3.1 and 3.2 and 2.2 from your draft.

>>>> 
>>>> On Mon, Jul 29, 2013 at 9:36 AM, Nat Sakimura
<sakimura at gmail.com> wrote: 
>>>> 
>>>>> Yup. It is too late. The client
needs to know whether the server is secure or not to start with. 
>>>>>

>>>>>> I still think that a base definition of this shouldn't try and
address discovering or publishing support for the functionality. 
>>>>>

>>>>> Could you kindly propose a concrete method? A concrete text would
be even better. 
>>>>> 
>>>>> 2013/7/29 Brian Campbell
<bcampbell at pingidentity.com> 
>>>>> 
>>>>>> As John pointed out, putting
metainfo about support into the token response is too late in the flow.

>>>>>> 
>>>>>> I still think that a base definition of this shouldn't
try and address discovering or publishing support for the functionality.

>>>>>> 
>>>>>> On Mon, Jul 29, 2013 at 9:28 AM, Nat Sakimura
<sakimura at gmail.com> wrote: 
>>>>>> 
>>>>>>> OK. Fair enough. 
>>>>>>>

>>>>>>> I will change it to the invalid_grant. 
>>>>>>> 
>>>>>>> What
do you think about the idea for "meta"? 
>>>>>>> 
>>>>>>> 2013/7/29
Brian Campbell <bcampbell at pingidentity.com> 
>>>>>>> 
>>>>>>>> It's
really not client authentication. It's something that links the initial
authorization request with the corresponding access token request, which
enables detecting a particular problem/attack. Similar to a mismatch on
the redirect URI value between the authorization request and the
corresponding access token request, it's the grant (or transaction) that
is invalid. 
>>>>>>>> 
>>>>>>>>
http://tools.ietf.org/html/rfc6749#section-5.2 [4]
>>>>>>>> 
>>>>>>>>
invalid_grant
>>>>>>>> 
>>>>>>>> The provided authorization grant (e.g.,
authorization
>>>>>>>> 
>>>>>>>> code, resource owner credentials) or
refresh token is
>>>>>>>> 
>>>>>>>> invalid, expired, revoked, does not
match the redirection
>>>>>>>> 
>>>>>>>> URI used in the authorization
request, or was issued to
>>>>>>>> 
>>>>>>>> another client. 
>>>>>>>>

>>>>>>>> Discovery is maybe useful but is definitely not necessary.
What is necessary is to define the parameter(s) and their treatment on
the authorization request and access token request so that clients and
servers can interop. 
>>>>>>>> 
>>>>>>>> On Mon, Jul 29, 2013 at 9:07
AM, Nat Sakimura <sakimura at gmail.com> wrote:
>>>>>>>> 
>>>>>>>>> Hi
Brian, 
>>>>>>>>> 
>>>>>>>>> inline: 
>>>>>>>>> 
>>>>>>>>> 2013/7/29
Brian Campbell <bcampbell at pingidentity.com>
>>>>>>>>> 
>>>>>>>>>> IMHO,
invalid_grant is the proper error response code, not
invalid_client.
>>>>>>>>> 
>>>>>>>>> I have thought a bit about that
when I was writing it down. 
>>>>>>>>> 
>>>>>>>>> invalid_grant is
concerned about the token which has been previously issued. 
>>>>>>>>>

>>>>>>>>> invalid_client is concerned about the client authentication.

>>>>>>>>> 
>>>>>>>>> In the initial path, I had it as invalid_grant,
then, I thought - well, it is the client 
>>>>>>>>> 
>>>>>>>>>
authentication that is failing when the client has provided invalid tcs.

>>>>>>>>> 
>>>>>>>>> The code is correct. It is the client
authentication which is going wrong, is it not? 
>>>>>>>>> 
>>>>>>>>>>
Along the same lines, I'd like to see it named something more like
"message correlation id" rather than anything involving client
secret.
>>>>>>>>> 
>>>>>>>>> The name "message correlation identifier"
does not convey the nature of the parameter, which is the high entropy
credential for the client. Just for the sake of the correlation, it does
not have to have a high entropy. Thus, I have chosen the name.

>>>>>>>>> 
>>>>>>>>> I have thought of making a new file but then that
would amount to having the client hit those discovery endpoints twice.

>>>>>>>>> 
>>>>>>>>> I did not want the duplicate situation that
resulted in the dynamic client registration. That's why I am referring
OpenID Connect. 
>>>>>>>>> 
>>>>>>>>> OpenID Connect originated the
Discovery and Registration. On the hind site, even registration should
have been referring OpenID Connect documents instead of duplicating. At
least, that's how academic papers work :-) 
>>>>>>>>> 
>>>>>>>>> Another
idea is to have the metadata come back in the token response. 
>>>>>>>>>

>>>>>>>>> I actually prefer this. It increases the server traffic a
bit, though. 
>>>>>>>>> 
>>>>>>>>> The way it works is this. 
>>>>>>>>>

>>>>>>>>> Instead of doing the discovery and caching it at the client,
the client finds the server capability from the token endpoint
reference. For this, the server includes something like: 
>>>>>>>>>

>>>>>>>>> "meta": { 
>>>>>>>>> 
>>>>>>>>> "tcs_supported":true;

>>>>>>>>> 
>>>>>>>>> } 
>>>>>>>>> 
>>>>>>>>> You guys know that I like
this idea because then I would have a stub to put link relationship
there as well. 
>>>>>>>>> 
>>>>>>>>> Do you like the idea? If so, I can
update the draft in this manner. 
>>>>>>>>> 
>>>>>>>>> Well, perhaps I
should anyways. 
>>>>>>>>> 
>>>>>>>>> Thanks for pointing out.

>>>>>>>>> 
>>>>>>>>> Best, 
>>>>>>>>> 
>>>>>>>>> Nat 
>>>>>>>>>

>>>>>>>>> On Sun, Jul 28, 2013 
>>>>>>>>> 
>>>>>>>>>> p> 
>>>>>>>>>>

>>>>>>>>>>> As some of you knows, passing the code securely to a native
app on iOS platform is next to impossible. Malicious application may
register the same custom scheme as the victim application and hope to
obtain the code, whose success rate is rather high. 
>>>>>>>>>>>

>>>>>>>>>>> We have discussed about it during the OpenID Conenct
Meeting at IETF 87 today, and I have captured the discussion in the form
of I-D. It is pretty short and hopefully easy to read. 
>>>>>>>>>>>

>>>>>>>>>>> You can find it at: 
>>>>>>>>>>> 
>>>>>>>>>>>
https://bitbucket.org/Nat/drafts/src/ [1] 
>>>>>>>>>>> 
>>>>>>>>>>>
Comments are welcome. 
>>>>>>>>>>> 
>>>>>>>>>>> -- 
>>>>>>>>>>> Nat
Sakimura (=nat) 
>>>>>>>>>>> 
>>>>>>>>>>> Chairman, OpenID
Foundation
>>>>>>>>>>> http://nat.sakimura.org/ [2]
>>>>>>>>>>> @_nat_en

>>>>>>>>>>> 
>>>>>>>>>>>
_______________________________________________
>>>>>>>>>>>
Openid-specs-ab mailing list
>>>>>>>>>>>
Openid-specs-ab at lists.openid.net
>>>>>>>>>>>
http://lists.openid.net/mailman/listinfo/openid-specs-ab [3]
>>>>>>>>>>

>>>>>>>>>> -- 
>>>>>>>>>> Nat Sakimura (=nat)
>>>>>>>>>
argin-bottom-alt: auto;">Chairman, OpenID Foundation
>>>>>>>>>
http://nat.sakimura.org/ [2]
>>>>>>>>> @_nat_en
>>>>>>> 
>>>>>>> --

>>>>>>> Nat Sakimura (=nat) 
>>>>>>> 
>>>>>>> Chairman, OpenID
Foundation
>>>>>>> http://nat.sakimura.org/ [2]
>>>>>>> @_nat_en
>>>>>

>>>>> -- 
>>>>> Nat Sakimura (=nat) 
>>>>> 
>>>>> Chairman, OpenID
Foundation
>>>>> http://nat.sakimura.org/ [2]
>>>>> @_nat_en
>>> 
>>> --

>>> Nat Sakimura (=nat) 
>>> 
>>> Chairman, OpenID Foundation
>>>
http://nat.sakimura.org/ [2]
>>> @_nat_en 
>>> 
>>>
_______________________________________________
>>> 
>>> Openid-specs-ab
mailing list
>>> 
>>> Openid-specs-ab at lists.openid.net
>>> 
>>>
http://lists.openid.net/mailman/listinfo/openid-specs-ab [3]




Links:
------
[1] https://bitbucket.org/Nat/drafts/src/
[2]
http://nat.sakimura.org/
[3]
http://lists.openid.net/mailman/listinfo/openid-specs-ab
[4]
http://tools.ietf.org/html/rfc6749#section-5.2
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