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RE: [foaf-protocols] Redirects continued -- was: Problem with certificate on home-grown WebID

From: Peter Williams <home_pw@msn.com>
Date: Wed, 21 Dec 2011 09:05:16 -0800
Message-ID: <SNT143-W64AECC2B31AD46D5BE1CDB92A50@phx.gbl>
CC: <foaf-protocols@lists.foaf-project.org>, "public-xg-webid@w3.org" <public-xg-webid@w3.org>, <sebastian@trueg.de>

Our colleague from the BBC already made the case for redirects. The case is just normal, in larger websites. The content producer and the content manager are different parties, in the publishing world. Content manager get to reorganize links, as they control when and if content gets un/published, and where it gets re-published. The question is, what does the spec say about the security threats, and what are the counter measures?  > From: henry.story@bblfish.net
> Date: Wed, 21 Dec 2011 17:19:36 +0100
> To: pierre-antoine.champin@liris.cnrs.fr
> CC: foaf-protocols@lists.foaf-project.org; public-xg-webid@w3.org; sebastian@trueg.de
> Subject: Re: [foaf-protocols] Redirects continued -- was: Problem with	certificate on home-grown WebID
> 
> 
> On 21 Dec 2011, at 16:57, Pierre-Antoine Champin wrote:
> 
> > Hi,
> > 
> > I had the same misunderstanding as Sebastian, creating WebID
> >  http://champin.net/pa
> > 
> > I now created
> >  http://champin.net/#pa
> > (which I too prefer, btw).
> > 
> > But that one does not work with foafssl.org :-(
> 
> That's because at present it does not have redirection implemented and you resource redirects
> 
> $ curl -i  http://champin.net/ 
> HTTP/1.0 302 Found
> Server: BaseHTTP/0.3 Python/2.5.2
> Date: Wed, 21 Dec 2011 16:15:10 GMT
> Location: http://liris.cnrs.fr/~pchampin/
> Content-type: text/html
> Vary: Host
> 
> 
> > I attach the result page. It says
> > 
> >  The WebId Profile must be parseable Content and transformable to an
> >  RDF graph
> 
> yep, if I were to be serious about redirects I'd have to change that to say: we don't work with
> redirects.... 
> 
> Since we are looking for use case for webids that redirect, let me ask you: why did you find
> it important to have your webid redirect?
> 
> 
> Henry
> 
> > 
> > but RDF Validator is happy with it:
> > 
> > http://www.w3.org/RDF/Validator/ARPServlet?URI=http%3A%2F%2Fchampin.net%2F&PARSE=Parse+URI%3A+&TRIPLES_AND_GRAPH=PRINT_TRIPLES&FORMAT=PNG_EMBED
> > 
> > and it is recognized by https://auth.fcns.eu/
> > 
> >  pa
> > 
> > 
> > On 12/21/2011 02:30 PM, Henry Story wrote:
> >> 
> >> On 21 Dec 2011, at 14:05, Sebastian Trüg wrote:
> >> 
> >>> On 12/21/2011 11:19 AM, Henry Story wrote:
> >>>> 
> >>>> On 21 Dec 2011, at 09:55, Sebastian Trüg wrote:
> >>>> 
> >>>>> Attached you find the result from https://foafssl.org/test/WebId. To be
> >>>>> honest I am not sure if it succeeded or not, the output confuses me. :/
> >>>> 
> >>>> yes, the output of this test suite is not as well finished as the previous
> >>>> one. And there is a bug there, I'll fix.
> >>>> 
> >>>> Ok, so you are using a WebID that redirects. I would suggest against it for
> >>>> two reasons:
> >>>> 
> >>>> -1. It increases the verification time for the verifier: the verifier has
> >>>>   to potentially do 2 HTTP connections, and in any case it has to do back
> >>>>   and forth
> >>>> -2 It is possible that some implementations don't support redirect, as it is
> >>>>   one of these less obvious features of the web. As soon as you add complexity
> >>>>   you add ways things can go wrong, and your identity is perhaps important 
> >>>>   enough for you not to want these things to go wrong
> >>>>   (In this case my implementation does not support it. But I can add it)
> >>>> -3 We believe we have worked out the security characteristics of redirects, 
> >>>>   but they are less obvious than the simple GET and will require more work,
> >>>>   so we have no language in the spec at present covering those - it's undefined
> >>>>   one might say. In any case they confuse Peter Williams, and risk confusing
> >>>>   military grade security people a lot more. So if you want to log in to higher
> >>>>   security sites you may find redirects create confusion with those people
> >>>>   implementing them. This comes up in ISSUE-64
> >>>>   http://www.w3.org/2005/Incubator/webid/track/issues/64
> >>>> 
> >>>> Does that make sense?
> >>> 
> >>> Well, yes. However, I am confused. You directed me to the site which I
> >>> took this setup from.
> >> 
> >> http://www.w3.org/TR/2008/NOTE-swbp-vocab-pub-20080828/
> >> 
> >> Yes, it is true that the "Best Practice Recipes for Publishing RDF Vocabularies"
> >> covers two cases one of which uses a redirect. The redirect is as we mentioned
> >> may require us to think things through in a bit more detail, though I don't think
> >> it is a big issue.
> >> 
> >>> Also you mentioned that it would be nicer to have
> >>> web ids like http://www.trueg.de/sebastian instead of something like
> >>> http://www.trueg.de/sebastian/foaf[#me].
> >> 
> >>> So which is it? :)
> >> 
> >> I think I mentioned WebIDs like 
> >> 
> >> http://www.trueg.de/sebastian#me 
> >> 
> >> rather than 
> >> 
> >> http://www.trueg.de/sebastian.rdf#me
> >> 
> >> not 
> >> 
> >> http://www.trueg.de/sebastian
> >> 
> >> with a redirect.
> >> 
> >> I think there is a pragmatic consideration in favour of the # one to do with reduction
> >> in communication costs. 
> >> 
> >> But you are right that this would do well to be more clearly specified in the 
> >> spec.
> >> 
> >>> 
> >>>>   So having said that there are a number of redirect types, 
> >>>> http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html
> >>>> 
> >>>> 	300 Multiple Choices
> >>>> 	301 Moved Permanently
> >>>> 	302 Found  // we can ignore this one
> >>>> 	303 See Other
> >>>> 	304 Not Modified
> >>>> 	305 Use Proxy
> >>>> 	307 Temporary Redirect
> >>>> 
> >>>> and one needs to consider which of these have what types of security implications, if any.
> >>>> Perhaps there is not much more to do here than to just think it though. But if we want to
> >>>> help implementors implement the WebId protocol so that you get a consistent experience between
> >>>> each verification service, and so that you are not left out in the cold inexplicably
> >>>> some places and not others, then we need to work this out. As you see it is easier and more
> >>>> efficient to stick to #urls.
> >>>> 
> >>>> The question is if there are any good rason for non #urls in our authentication use case.
> >>> 
> >>> Only the prettyness of the URL which should be irrelevant in the end
> >>> since the point is to not show it to the user, right.
> >> 
> >> yes, that alone would not make for a very good reason. Perhaps there are others. It would
> >> be good to collect them.
> >> 
> >>> I simply followed your advise, or maybe misunderstood your advise...
> >> 
> >> No you are doing well :-) You're helping us think about this issue 2^6 here. It's an important
> >> one. 
> >> 
> >> Henry
> >> 
> >>> 
> >>> Cheers,
> >>> Sebastian
> >>> 
> >>>> Henry
> >>>> 
> >>>>> 
> >>>>> Cheers,
> >>>>> Sebastian
> >>>>> 
> >>>>> On 12/20/2011 10:44 PM, Henry Story wrote:
> >>>>>> Ok, I have updated the server to the new scala version.
> >>>>>> 
> >>>>>> I hope it remains up until you read this e-mail. I am still working on the details
> >>>>>> of how to release it. But if it is still up please let me know if it works now
> >>>>>> with your key.
> >>>>>> 
> >>>>>> Henry
> >>>>>> [snip]
> >>>> 
> >>>> Social Web Architect
> >>>> http://bblfish.net/
> >>>> 
> >>>> 
> >> 
> >> Social Web Architect
> >> http://bblfish.net/
> >> 
> >> 
> > 
> > <WebId.html>
> 
> Social Web Architect
> http://bblfish.net/
> 
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Received on Wednesday, 21 December 2011 17:05:55 GMT

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