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<title>Re: Problem with nonces and HTTP GET</title>
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Nat, I know you’ve been an advocate of artifact binding, what
are your thoughts here?<o:p></o:p></span></p>
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#0033CC'>Cheers,<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#0033CC'><br>
Brian<o:p></o:p></span></p>
<p class=MsoNormal><b><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
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<p class=MsoNormal><b><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#0033CC'><a href="http://www.linkedin.com/pub/0/10/254"><span
style='color:#0033CC'>Brian Kissel</span></a><o:p></o:p></span></b></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#0033CC'>CEO - JanRain, Inc.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#0033CC'>bkissel@janrain.com<o:p></o:p></span></p>
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<p class=MsoNormal><b><i><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#0033CC'>Increase registrations, engage users, and grow your brand with
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<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Allen Tom
[mailto:atom@yahoo-inc.com] <br>
<b>Sent:</b> Wednesday, January 27, 2010 3:02 PM<br>
<b>To:</b> Brian Kissel; Andrew Arnott; John Bradley; Breno de Medeiros; specs<br>
<b>Cc:</b> Drebes, Larry; Ellin, Brian<br>
<b>Subject:</b> Re: Problem with nonces and HTTP GET<o:p></o:p></span></p>
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<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif"'>At least with regards to HuffPo – we ended
up removing attributes from the request to get under the 2KB url limit, which
eliminated the security warning since we can return the response via GET
instead of POST.<br>
<br>
At least in the near term, I’d like to compact AX so that we can squeeze in
more data – we should be able to do this for AX 1.1. OPs can also implement
this internal artifact mechanism to switch from HTTPS to HTTP before returning
the data. <br>
<br>
In the longer term, some form of Artifact Binding would probably be better, but
I guess this would take longer to implement.<br>
<br>
Allen<br>
<br>
<br>
<br>
On 1/22/10 10:59 AM, "Brian Kissel" <<a href="bkissel@janrain.com">bkissel@janrain.com</a>>
wrote:</span><o:p></o:p></p>
<p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'>+1 Allen, here’s what I get
on HuffPo, not very compelling and probably a trigger to “Cancel” to most
users. We need to fix this ASAP!<br>
<br>
<img border=0 width=562 height=157 id="_x0000_i1025"
src="cid:image001.png@01CA9F62.8692F5F0"><br>
<br>
</span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><br>
<span style='color:#0033CC'>Cheers,<br>
<br>
Brian<br>
<b>___________<br>
<br>
Brian Kissel <<a href="http://www.linkedin.com/pub/0/10/254">http://www.linkedin.com/pub/0/10/254</a>>
<br>
</b>CEO - JanRain, Inc.<br>
<a href="bkissel@janrain.com">bkissel@janrain.com</a><br>
Mobile: 503.342.2668 | Fax: 503.296.5502<br>
519 SW 3rd Ave. Suite 600 Portland, OR 97204<br>
<br>
<b><i>Increase registrations, engage users, and grow your brand with RPX.
Learn more at </i></b></span><b><i><span style='color:red'>www.rpxnow.com
<<a href="http://www.rpxnow.com/">http://www.rpxnow.com/</a>> <br>
</span></i></b><span style='color:#1F497D'><br>
</span><br>
</span><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> <a
href="openid-specs-bounces@lists.openid.net">openid-specs-bounces@lists.openid.net</a>
[<a href="mailto:openid-specs-bounces@lists.openid.net">mailto:openid-specs-bounces@lists.openid.net</a>]
<b>On Behalf Of </b>Allen Tom<br>
<b>Sent:</b> Friday, January 22, 2010 10:43 AM<br>
<b>To:</b> Andrew Arnott; John Bradley; Breno de Medeiros; specs<br>
<b>Subject:</b> Re: Problem with nonces and HTTP GET<br>
</span><br>
<span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>The SSL
security warning is a really terrible UX, and I agree that it doesn’t make
sense to warn on POST but not on GET.<br>
<br>
Yahoo is running into the 2KB limit (and the associated SSL warning) with alarming
frequency and it’s really hurting OpenID relative to the proprietary SSO
solutions. <br>
<br>
For a real live example of how the giant AX names are hurting OpenID, see <a
href="http://www.huffingtonpost.com">http://www.huffingtonpost.com</a> – click
on the Login link, then the “Connect with Yahoo” button. This kicks off the
Hybrid OpenID+Oauth+AX flow which requires a POST response – forcing the user
to click through a security warning to complete the sign in flow. The
non-OpenID SSO choices (Facebook/Twitter/GFC) do not have this issue.<br>
<br>
With regards to changing browsers to not display SSL warnings for POST, or
relying on smart OpenID clients – we really need a solution right now, since
the proprietary alternatives are rapidly being adopted.<br>
<br>
WRT the nonce – I think it would make more sense for RPs to just check the
timestamp, and allow replay for a “narrow” window, like 10 minutes. There are
many legitimate reasons why a request could be replayed – intermediate proxy
servers might do weird things, the user might hit reload/back/forward etc.<br>
<br>
Allen<br>
<br>
<br>
On 1/22/10 10:06 AM, "Andrew Arnott" <<a
href="andrewarnott@gmail.com">andrewarnott@gmail.com</a>> wrote:<br>
Ideally we could use POST, but avoid the browser warning that information is
crossing the SSL world into the non-SSL world. This might be arguable
anyway since sending information can be done with GET or POST, so why warn for
POST and not for GET? If we can get browsers to not warn for POST we're
gold.<br>
<br>
Alternatively, and perhaps more likely, if we're moving in the direction of
smart client browser (plugins), and these have been shown to benefit from
extensions to the OpenID spec, perhaps we can leverage these to always use POST
without displaying the warning to the user somehow. <br>
--<br>
Andrew Arnott<br>
"I [may] not agree with what you have to say, but I'll defend to the death
your right to say it." - S. G. Tallentyre<br>
<br>
<br>
On Fri, Jan 22, 2010 at 9:14 AM, John Bradley <<a
href="john.bradley@wingaa.com">john.bradley@wingaa.com</a>> wrote:<br>
The big problem with POST is RP's that use non-ssl endpoints. <br>
<br>
One possibility is that the IdP could look at the return_to and discover if it
is safe to use POST.<br>
<br>
In SAML SSO POST is the most common way to return the token. <br>
<br>
The other option is artifact binding. That way the nonce is not in the
GET, though you probably wind up with the same effect if the RP tries to
resolve the artifact more than once.<br>
<br>
John B.<br>
On 2010-01-22, at 12:39 PM, Andrew Arnott wrote:<br>
HTTP GET is supposed to be completely effect-free on the server. But
nonces in OpenID messages violate that aspect of the HTTP spec, since any
subsequent GET with the same positive assertion will (or should) fail. I
speculate that some random login failures on StackOverflow <<a
href="http://meta.stackoverflow.com/questions/32247/cant-login-to-so-with-openid-the-signature-verification-failed/36583#36583">http://meta.stackoverflow.com/questions/32247/cant-login-to-so-with-openid-the-signature-verification-failed/36583#36583</a>>
may be caused because a browser, an accelerator plugin, or a proxy
attempted to repeat the assertion-carrying GET request (since that's supposed
to be safe), and a subsequent request is the one whose response is displayed in
the browser, failing user login.<br>
<<a
href="http://meta.stackoverflow.com/questions/32247/cant-login-to-so-with-openid-the-signature-verification-failed/36583#36583">http://meta.stackoverflow.com/questions/32247/cant-login-to-so-with-openid-the-signature-verification-failed/36583#36583</a>>
<br>
POST is a better fit with the HTTP spec for how the message is actually
processed on the server. I know lately we've been looking for ways to
cram more data into < 2KB payloads so we can get off POST and onto GET since
the user experience is better. But I wonder if we can put our heads
together and figure out how to have our cake and eat it too with this nonce
problem. This error doesn't come up often, but it can come up, apparently
does come up, and is a natural side-effect of the way OpenID communicates.<br>
<br>
Any ideas?<br>
<br>
--<br>
Andrew Arnott<br>
"I [may] not agree with what you have to say, but I'll defend to the death
your right to say it." - S. G. Tallentyre<br>
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