[Openid-specs-ab] token_endpoint_auth_method Registration example error?

[John Bradley]

If you want a client to authenticate multiple ways just don't register a prefrence.

This was intended to prevent IdP from accepting weaker methods of authentication from attackers.   If you are not doing that then the client should be able to use anything the server supports.

Now if the client doesn't register a public key then some methods will fail, but that is a client decision.

I think trying to say I only want to use 2 of the 5 available methods is overkill.

The client should just pick the one it is going to use.

If it really needs two methods maybe it is really two clients and somebody is fudging things a bit.

John B.

On 2013-01-23, at 4:18 PM, Justin Richer <jricher at mitre.org> wrote:

> Actually come to think of it, why wouldn't a client be able to do both client_secret_basic and client_secret_post to a server that supports them? It's the same info presented in *almost* the same way. 
> 
> This combination may be the exceptional case, though, as the other types (client_secret_jwt,private_key_jwt, or even "none" that OIDC hasn't adopted yet) aren't particularly mutually compatible. 
> 
>  -- Justin
> 
> 
> On 01/23/2013 10:53 AM, Justin Richer wrote:
>> OK, thanks for catching that. I'll file a bug against Oauth2 Dynreg as well (which has the same examples). John is right that it is defined as a single value and the examples are off.
>> 
>>  -- Justin
>> 
>> On 01/23/2013 10:03 AM, Mike Jones wrote:
>>> That’s what I thought.  Thanks for confirming.
>>>  
>>>                                                             -- Mike
>>>  
>>> From: John Bradley [mailto:ve7jtb at ve7jtb.com] 
>>> Sent: Wednesday, January 23, 2013 7:02 AM
>>> To: Mike Jones
>>> Cc: openid-specs-ab at lists.openid.net
>>> Subject: Re: [Openid-specs-ab] token_endpoint_auth_method Registration example error?
>>>  
>>> The server may support multiple methods, but the client MUST only register one, so it shouldn't be multi value for simplicity.
>>>  
>>> If you need two auth methods they should be different client_id.
>>>  
>>> This is intended mostly to enhance security and prevent a server from taking client_secret_basic from an attacker when the real client is using private_key_jwt.
>>>  
>>> John B.
>>>  
>>> On 2013-01-23, at 9:07 AM, Mike Jones <Michael.Jones at microsoft.com> wrote:
>>> 
>>> 
>>> Registration contains the following definition:
>>>  
>>> token_endpoint_auth_method
>>> OPTIONAL. Requested authentication method for the Token Endpoint. The options areclient_secret_post, client_secret_basic, client_secret_jwt, and private_key_jwt, as described in Section 2.2.1 of [OpenID.Messages]. Other Authentication methods may be defined by extension. If unspecified or omitted, the default is client_secret_basic HTTP Basic Authentication Scheme as specified in Section 2.3.1 of [RFC6749].
>>>  
>>> It later uses “token_endpoint_auth_method” in two example result values in this manner:
>>>  
>>> "token_endpoint_auth_method":
>>>    "client_secret_basic client_secret_post",
>>>  
>>> This looks like a bug to me, since the string appears to be trying to contain multiple values.
>>>  
>>> Thus, I’m changing the string used to just "client_secret_basic" to make the example correct.  But I thought I’d point this out in case the example may have been intentional in some manner.
>>>  
>>>                                                             -- Mike
>>>  
>>> _______________________________________________
>>> Openid-specs-ab mailing list
>>> Openid-specs-ab at lists.openid.net
>>> http://lists.openid.net/mailman/listinfo/openid-specs-ab
>>>  
>>> 
>>> 
>>> _______________________________________________
>>> Openid-specs-ab mailing list
>>> Openid-specs-ab at lists.openid.net
>>> http://lists.openid.net/mailman/listinfo/openid-specs-ab
>> 
>> 
>> 
>> _______________________________________________
>> Openid-specs-ab mailing list
>> Openid-specs-ab at lists.openid.net
>> http://lists.openid.net/mailman/listinfo/openid-specs-ab
> 
> _______________________________________________
> Openid-specs-ab mailing list
> Openid-specs-ab at lists.openid.net
> http://lists.openid.net/mailman/listinfo/openid-specs-ab

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openid.net/pipermail/openid-specs-ab/attachments/20130123/581111df/attachment.html>