Re: [sipcore] I-D Action: draft-ietf-sipcore-sip-token-authnz-02.txt

Paul Kyzivat <pkyzivat@alum.mit.edu> Thu, 11 July 2019 13:50 UTC

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To: Christer Holmberg <christer.holmberg@ericsson.com>, "sipcore@ietf.org" <sipcore@ietf.org>
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From: Paul Kyzivat <pkyzivat@alum.mit.edu>
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Date: Thu, 11 Jul 2019 09:50:06 -0400
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Subject: Re: [sipcore] I-D Action: draft-ietf-sipcore-sip-token-authnz-02.txt
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On 7/11/19 3:03 AM, Christer Holmberg wrote:
> Hi,
> 
> ...
> 
>>> All I am saying is that one should not send a token to someone that it has NOT been issued for.
>>     
>>     Then you are saying that a token should *never* be included in a request
>>     to a target for which you have not received a challenge some time in the
>>     past.
>>     
>>     That is a bit extreme, but I guess you can specify that if you think it
>>     is the right thing to do.
> 
> That is my understanding of the generic OAuth security considerations: you don't give a token to someone it was not intended for.
> 
> Of course, if you know (based on whatever configuration/policy) that it's ok to give the token to the target I guess you could do it.
>      
>>     But note that this logic won't always work for Proxy-Authenticate. You
>>     *might* know that a particular proxy will be visited (if it is mentioned
>>     on a Route header), but it is pretty common for the request to visit
>>     proxies unknown (at least in advance) to the UAC.
>    
> It is important to remember that, since the token needs to be protected, a proxy needs to have the associated protection credentials to be able to access the token.

I'm lost here. How is the token protected? Is it because it is passed by 
reference, and other credentials are needed to dereference it? Or is it 
passed by value but encrypted?

If it is protected, then why is there any concern over who it is given to?

	Thanks,
	Paul