Should we recommend that return_to url is always HTTPS? What about realm?

George Fletcher gffletch at aol.com
Thu May 14 17:17:13 UTC 2009


John,

By PPID do you mean the InfoCard unique User:RP identifier? Or are you 
referring to the use of pseudonymous identifiers within OpenID?

If the latter, I didn't see the thread that was suggesting that the 
pseudonymous identifiers match the realm. I would be against that 
suggestion. The spec requires the RP to do discovery on the pseudonymous 
identifier to prove that the OP that returned the response is 
authoritative for the pseudonymous identifier. With this mechanism, the 
realm should not need to match the identifier.

Thanks,
George

John Bradley wrote:
> Luke,
>
> From a URI point of view the two URI are different and it can't 
> be considered steeping up security.
>
> I understand that is what would normally happen but it violates some 
> basic principals.
>
> It also compromises RP discovery.  
>
> A wijldcard in the realm may be the better solution.  Though you may 
> not want to include matching all protocols.
>
> In the other thread we are discussing PPID like identifiers.   If they 
> are based on the realm as people are discussing,  introducing 
> wildcards etc introduces the question of realm normalization on that side.
>
> John Bradley
>
>
> On 14-May-09, at 11:25 AM, Luke Shepard wrote:
>
>> So, RP delegation sounds like a very general solution to the problem, 
>> and seems okay to push for. But I think there’s a much simpler 
>> solution that solves the specific problem I described below:
>>
>> RULE:
>>   If the realm is http, then the return_to can be either http or https.
>>
>> So this would be legal:
>>
>> realm: *http*://open.lukeshepard.com/
>> return_to: *https*://open.lukeshepard.com/openid/receiver.php
>>
>> This would NOT be legal – you can’t go the other way.
>>
>> realm: *https*://open.lukeshepard.com/
>> return_to: *http*://open.lukeshepard.com/openid/receiver.php
>>
>> So, the receiver should be allowed to INCREASE its security level 
>> from the realm, but not decrease.
>>
>> This is analogous to wildcards for the protocol instead of just 
>> subdomain. Another alternative would be to have explicit wildcards 
>> for the protocol, or to allow realms with relative protocols, like:
>>
>> explicit wildcard: *://open.lukeshepard.com
>> relative protocol: //open.lukeshepard.com
>>
>>
>>
>> On 5/14/09 7:19 AM, "John Bradley" <jbradley at mac.com> wrote:
>>
>>     I agree that RP delegation should be possible and even desirable.
>>
>>     To do that safely the OP needs to do RP discovery over SSL or
>>     discover a XRD with detached sig for the RP.
>>
>>     Otherwise you open up Man in the Middle attacks.  
>>
>>     My point was that in the existing spec to prevent interception of
>>     tokens and attributes,  the Realm that is displayed by the OP to
>>     the user needs to match where the assertion is sent.
>>
>>     I agree that this is something that should be addressed in openID
>>     2.1 ether for XRD with dsig or via XRDS with TLS.
>>
>>     John B.
>>
>>     On 14-May-09, at 12:24 AM, Dirk Balfanz wrote:
>>
>>         I don't see why a realm shouldn't be able to delegate to a
>>         return_to URL the same way that a user id can delegate to an
>>         OP endpoint. This includes delegating from http to https, or
>>         even to a different domain altogether. Over on the XRI TC
>>         we've been talking about how to do this securely, e.g., by
>>         signing the XRD that does the delegation:
>>         http://wiki.oasis-open.org/xri/XrdOne/XmlDsigProfile
>>          
>>         Dirk.
>>
>>         On Wed, May 13, 2009 at 7:43 PM, John Bradley
>>         <jbradley at mac.com> wrote:
>>         > Luke,
>>         > Realm was called trust_root in 1.1, and is a bit like
>>         audience restriction
>>          > in SAML.
>>         > It is the display version of the return_to, and also used
>>         for RP discovery
>>         > by the OP.
>>         > I am not certain what the problem is with it being https: if
>>         the return_to
>>         > is https:.
>>          > There is explicitly no connection to be inferred by DNS
>>         authority between
>>         > URI differing in scheme.   
>>         > Differentiating TLS by its own scheme is a decision we have
>>         to live with.
>>         > The user should consent to authentication for the site they
>>         are logging
>>          > into.
>>         > http://open.lukesheppard.com and
>>         https://open.lukesheppard.com could
>>         > be different sites.
>>         > If the RP has both HTTP and HTTPS the best practice would be
>>         to always use
>>          > the https: version for realm so that RP discovery cant be
>>         spoofed via DNS.
>>         > Regards
>>         > John B.
>>         > On 13-May-09, at 2:10 AM, specs-request at openid.net wrote:
>>          >
>>         > Date: Tue, 12 May 2009 23:10:38 -0700
>>         > From: Luke Shepard <lshepard at facebook.com>
>>         > Subject: Should we recommend that return_to url is always
>>         HTTPS? What
>>          > about realm?
>>         > To: OpenID Specs Mailing List <specs at openid.net>
>>         > Message-ID: <C62FB26E.BCE7%lshepard at facebook.com
>>         <mailto:C62FB26E.BCE7%25lshepard at facebook.com> >
>>          > Content-Type: multipart/related;
>>         > boundary="_004_C62FB26EBCE7lshepardfacebookcom_";
>>         > type="multipart/alternative"
>>         >
>>         > --_004_C62FB26EBCE7lshepardfacebookcom_
>>         > Content-Type: multipart/alternative;
>>          > boundary="_000_C62FB26EBCE7lshepardfacebookcom_"
>>         >
>>         > --_000_C62FB26EBCE7lshepardfacebookcom_
>>         > Content-Type: text/plain; charset="iso-8859-1"
>>         > Content-Transfer-Encoding: quoted-printable
>>          >
>>         > In testing my relying party, it seems clear that the
>>         return_to url SHOULD a=
>>         > lways be HTTPS. Therefore, then, the realm will always need
>>         to be HTTPS as =
>>         > well.
>>         >
>>         > If the return_to is HTTP, then if the response comes in the
>>         form of a POST =
>>          > from a provider that supports SSL, then the user will see
>>         a browser warning=
>>         > for posting to an insecure form.
>>         >
>>         > Here's an example:
>>         >
>>         > - realm: http://open.lukeshepard.com/
>>          > - return_to: http://open.lukeshepard.com/openid/receiver.php
>>         > - provider endpoint: https://www.google.com/accounts/o8/ud
>>          >
>>         > Let's suppose that the response is too long for a GET
>>         redirect, so the prov=
>>         > ider chooses to POST (as Google and others sometimes do).
>>         >
>>         > The user would see a warning like this:
>>         >
>>          > [cid:3325014638_6495490]
>>         >
>>         > To preserve the user experience and avoid that popup,
>>         relying parties would=
>>         > want to make sure their receiver is HTTPS.
>>         >
>>         > Alternative
>>         >
>>         > What do you think about loosening the realm/return_to
>>         protocol/domain match=
>>          > requirements?
>>         >
>>         > This kinda sucks though, since it means the REALM also must
>>         be HTTPS, even =
>>         > though the HTTP version would seem to be "canonical". I
>>         wonder, would we al=
>>         > low an HTTPS return_to if the realm was HTTP? It seems that
>>         the HTTP versio=
>>          > n of the realm would be better, and should be able to mean
>>         "accept either p=
>>         > rotocol". Or better yet, you should be able to specify a
>>         realm without a pr=
>>         > otocol at all.
>>         >
>>         > Thoughts?
>>          >
>>         > _______________________________________________
>>         > specs mailing list
>>         > specs at openid.net
>>         > http://openid.net/mailman/listinfo/specs
>>          >
>>         >
>>
>>
>>
>
> =
> ------------------------------------------------------------------------
>
> _______________________________________________
> specs mailing list
> specs at openid.net
> http://openid.net/mailman/listinfo/specs
>   



More information about the specs mailing list