[Openid-specs-ab] jku and x5u

John Bradley ve7jtb at ve7jtb.com
Wed Apr 3 17:39:20 UTC 2013


I think we are agreeing that openID connect clients MUST ignore jku and and x5u elements in the JWS envelope, and may only use the jwk in the sub_kwk element if the issuer is 
https://self-issued.me.   

Note that the sub_jwk element is in the assertion body and not the envelope and will be ignored by a generic JOSE library.  

John 


On 2013-04-03, at 2:22 PM, Breno de Medeiros <breno at google.com> wrote:

> On Wed, Apr 3, 2013 at 10:17 AM, John Bradley <ve7jtb at ve7jtb.com> wrote:
>> I wasn't recommending changing the discovery mechanism.   We support out of band configuration.   There are a number of ways to do that, including typing it in.
>> 
>> One possible way is to use some sort of meta data from a federation.  That would require an extension document ad is out of scope.
>> 
>> We decided not to support discovery for domains without web servers on the top level.   I think Tim was the main proponent of dropping discovery support for other issuers.
>> 
>> For self issued there is no discovery the assertion is self contained.
> 
> Right. The problem here is not OOB. This is always possible in a
> federation. The problem is the prescription to parse jku in the
> absence of PKI trust. That's a recipe for generalized insecurity.
> 
>> 
>> John B.
>> On 2013-04-03, at 2:06 PM, Breno de Medeiros <breno at google.com> wrote:
>> 
>>> On Wed, Apr 3, 2013 at 10:03 AM, John Bradley <ve7jtb at ve7jtb.com> wrote:
>>>> self issued is a special case where the public key is provided in the envelope directly and validated against the sig the sub is derived from the public key.
>>>> 
>>>> I don't think that is a problem.
>>>> 
>>>> For IdP that publish a discovery document that is authoritative that specifies the jku url not the JWT.
>>>> 
>>>> For idp who can't publish a discovery document RP will need to manually configure out of band as they do now for facebook and others, or there needs to be a trusted source of meta-data for those small IdP.
>>> 
>>> I disagree that the benefit of creating a complex and likely
>>> security-challenged discovery mechanism is worth the cost.
>>> 
>>>> 
>>>> John
>>>> 
>>>> On 2013-04-03, at 1:58 PM, Breno de Medeiros <breno at google.com> wrote:
>>>> 
>>>>> On Wed, Apr 3, 2013 at 9:56 AM, Breno de Medeiros <breno at google.com> wrote:
>>>>>> On Wed, Apr 3, 2013 at 1:54 AM,  <Axel.Nennker at telekom.de> wrote:
>>>>>>> Here are two use cases that would not work under the
>>>>>>> “${issuer}/.well-known/openid-configuration” assumption.
>>>>>>> 
>>>>>>> 1)      The issuer has no control over the top level domain’s files
>>>>>>> e.g. you rented some hosting space at
>>>>>>> https://geocities.yahoo.co.jp/KafkaTamura and this is the iss. Kafka can not
>>>>>>> change the top level openid-configuration only
>>>>>>> https://geocities.yahoo.co.jp/KafkaTamura/.well-known/openid-configuration
>>>>>>> 
>>>>>>> 2)      A self-issued OP on a phone
>>>>>>> The issuer could dynamically register its keys or provide the public key
>>>>>>> with the first token. The consumer would then ensure that the key is the
>>>>>>> same in subsequent tokens.
>>>>>> 
>>>>>> I am not interested in supporting either of these cases if it comes at
>>>>>> the expense of generalized insecurity on the common case. If the spec
>>>>>> wants to support these cases, it needs to be very careful on how to
>>>>>> coach the language.
>>>>> 
>>>>> And why can't _both_ of these cases be achieved though PKI-based means?
>>>>> 
>>>>> 
>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> From: openid-specs-ab-bounces at lists.openid.net
>>>>>>> [mailto:openid-specs-ab-bounces at lists.openid.net] On Behalf Of Tim Bray
>>>>>>> Sent: Tuesday, April 02, 2013 11:55 PM
>>>>>>> To: Hannes Tschofenig
>>>>>>> Cc: <openid-specs-ab at lists.openid.net>
>>>>>>> 
>>>>>>> 
>>>>>>> Subject: Re: [Openid-specs-ab] jku and x5u
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> From where I sit, the most obvious thing to do is look at the issuer claim,
>>>>>>> resolve ${issuer}/.well-known/openid-configuration, extract the jwk-url
>>>>>>> claim, fetch the jwk, and validate using that.  For the kind of
>>>>>>> consumer/internet stuff we do, wouldn't that nearly always be the right
>>>>>>> choice?
>>>>>>> 
>>>>>>> -T
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> On Tue, Apr 2, 2013 at 11:48 AM, Hannes Tschofenig
>>>>>>> <hannes.tschofenig at gmx.net> wrote:
>>>>>>> 
>>>>>>> Hi Tim,
>>>>>>> 
>>>>>>> There are three ways to shuffle keys around:
>>>>>>> 
>>>>>>> * per value: you include the key in the message
>>>>>>> * per reference: you include a pointer to the key (e.g., a URL)
>>>>>>> * out-of-band: here you just give the key a name without telling where to
>>>>>>> find it.
>>>>>>> 
>>>>>>> Needless to say that you have to be careful with all three mechanisms when
>>>>>>> it comes to security.
>>>>>>> 
>>>>>>> You are already thinking about a complete use case that goes beyond what
>>>>>>> these header parameters by itself are able to answer.
>>>>>>> 
>>>>>>> Ciao
>>>>>>> Hannes
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> On 04/02/2013 09:35 PM, Tim Bray wrote:
>>>>>>> 
>>>>>>> Sorry, I’m probably failing to understand because I’m a crypto moron,
>>>>>>> but if I want to use keys to validate a JWT allegedly from example.com
>>>>>>> 
>>>>>>> <http://example.com>, I’m not going to believe anything in the JWT until
>>>>>>> I’ve checked using example.com <http://example.com>’s keys, so why
>>>>>>> 
>>>>>>> 
>>>>>>> should I believe the JWT’s assertion about where to get the keys to
>>>>>>> validate it?  -T
>>>>>>> 
>>>>>>> 
>>>>>>> On Tue, Apr 2, 2013 at 11:27 AM, Mike Jones <Michael.Jones at microsoft.com
>>>>>>> 
>>>>>>> <mailto:Michael.Jones at microsoft.com>> wrote:
>>>>>>> 
>>>>>>>  Yes, that’s exactly it.  If you already know where the keys are or
>>>>>>>  what they are (for instance, if you’ve established that information
>>>>>>>  at registration time), there’s no need to use these parameters.  But
>>>>>>>  for some use cases, this is valuable information that can be
>>>>>>>  dynamically provided.  (The Key ID (“kid”) can also be dynamically
>>>>>>> 
>>>>>>>  provided, if appropriate to the use case.)____
>>>>>>> 
>>>>>>>  __ __
>>>>>>> 
>>>>>>>                                                                   --
>>>>>>>  Mike____
>>>>>>> 
>>>>>>>  __ __
>>>>>>> 
>>>>>>>  *From:*openid-specs-ab-bounces at lists.openid.net
>>>>>>>  <mailto:openid-specs-ab-bounces at lists.openid.net>
>>>>>>>  [mailto:openid-specs-ab-bounces at lists.openid.net
>>>>>>>  <mailto:openid-specs-ab-bounces at lists.openid.net>] *On Behalf Of
>>>>>>>  *Tim Bray
>>>>>>>  *Sent:* Tuesday, April 02, 2013 11:19 AM
>>>>>>>  *To:* <openid-specs-ab at lists.openid.net
>>>>>>>  <mailto:openid-specs-ab at lists.openid.net>>
>>>>>>>  *Subject:* [Openid-specs-ab] jku and x5u____
>>>>>>> 
>>>>>>>  __ __
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>>  Almost certainly I’m just missing something obvious, but I’m having
>>>>>>>  trouble understanding why the jku and x5u header claims exist.  The
>>>>>>>  idea is I get a message and believe the message’s assertion about
>>>>>>> 
>>>>>>>  where I should go to get the cert to validate the message?  -T____
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> _______________________________________________
>>>>>>> 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
>>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> --
>>>>>> --Breno
>>>>> 
>>>>> 
>>>>> 
>>>>> --
>>>>> --Breno
>>>>> _______________________________________________
>>>>> Openid-specs-ab mailing list
>>>>> Openid-specs-ab at lists.openid.net
>>>>> http://lists.openid.net/mailman/listinfo/openid-specs-ab
>>>> 
>>> 
>>> 
>>> 
>>> --
>>> --Breno
>> 
> 
> 
> 
> --
> --Breno

-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 4507 bytes
Desc: not available
URL: <http://lists.openid.net/pipermail/openid-specs-ab/attachments/20130403/b99d1a65/attachment.p7s>


More information about the Openid-specs-ab mailing list