Re: [community] from W3C….Fwd: Proposal: "User" header field

Melvin Carvalho melvincarvalho at gmail.com
Fri Jul 19 05:54:05 UTC 2013


On 19 July 2013 04:14, Nat Sakimura <sakimura at gmail.com> wrote:

> If that is the case, having IdP URI seems to meet the use case and do not
> get into the three problems that I have described previously, i.e.,
> security, privacy, and fraud.
>

Hi Nat, thanks for the feedback, this pattern is consistent with using an
IdP to address all three of these issues.  What you would do is dereference
the URL and look for the appropriate link header to find where the IdP is
located.



>
> Nat
>
>
> 2013/7/19 John Kemp <john at jkemp.net>
>
>> On Jul 18, 2013, at 5:00 PM, George Fletcher <gffletch at aol.com> wrote:
>>
>> > So from an authentication/validation perspective, it appears that the
>> data in the HTTP request must be tied in some secure way to the user
>> identified in the hint. Otherwise, it's easy for me to impersonate someone
>> by just sending a different hint.
>>
>> Yes, either the client must be trusted, "trusted but verified",  or the
>> "hint" is just a hint ;)
>>
>> >
>> > From an JOSE perspective, it could be the URL to a JWKS that contains
>> my individual public key data.
>>
>> Yes, that's the kind of thing they're talking about. Use this as an ID
>> and then authenticate/authorize via some other protocol. JOSE, or OpenID or
>> WebID.
>>
>> >
>> > I am a little worried about global correlation with a header like this.
>>
>> The particular worldview here though *wants* a URI to refer to 'you'.
>> Global correlation will indeed be possible if only a single URI is used to
>> refer to you.
>>
>> >
>> > Thanks for the explanation.
>> >
>> > I do agree with Torsten that using the Authorization header via OAuth2
>> Bearer seems like simpler solution. This can obviate the need for the
>> back-channel request for authorization.
>>
>> For an authorization use-case, perhaps. But WebID is, I think, what is
>> proposed here - http://www.w3.org/wiki/WebID
>>
>> JohnK
>>
>> >
>> > Thanks,
>> > George
>> >
>> > On 7/18/13 1:54 PM, Melvin Carvalho wrote:
>> >>
>> >> On 18 July 2013 18:59, George Fletcher <gffletch at aol.com> wrote:
>> >> I'm a little confused...  first the spec says
>> >> The current text includes: "It SHOULD NOT be used as an insecure form
>> of access protection."  -- This is the same as the "From" header (which may
>> contain an email address).  Do you think stronger wording is required.
>> >> and then you follow that up with
>> >> In particular, one thing we are working on in the Read Write Web
>> Community Group is fine grained access control for writing or appending a
>> file.  It's helpful to know who is trying to make a change before returning
>> e.g. SUCCESS or FORBIDDEN response codes.
>> >> Since there is no authentication or proof associated with the 'User'
>> header, how can you use it for fine grained access control? Is the
>> expectation that the value is an untrusted identification of the user that
>> can be used to optimize certain use cases? If so, I'm not sure which use
>> cases it helps?
>> >>
>> >> That you are able to identify yourself does not imply that verifying
>> that identity is impossible.  The auth part is simply not in scope, the
>> same as with the "From" header.
>> >>
>> >> In practice what we tend to do is dereference the URL and look for a
>> public key, then use PKI for verification, but that's only one way to do
>> auth.  There are many ways to do so, as John pointed out, you could
>> delegate to your OpenID provider too, so you get the best of all worlds.
>> >>
>> >>
>> >> Thanks,
>> >> George
>> >>
>> >> On 7/18/13 12:49 PM, Melvin Carvalho wrote:
>> >>>
>> >>>
>> >>>
>> >>> On 18 July 2013 01:54, John Kemp <john at jkemp.net> wrote:
>> >>> The problem, in general, with putting identifiers in HTTP requests is
>> that they get mistaken for being real things. User is no worse (or better)
>> than User-Agent. Remember all of the mess about how websites would attempt
>> to render sites to clients based on the contents of the User-Agent header,
>> and how long it's taken for something better to appear for that task?
>> >>>
>> >>> Yes, I agree that User-Agent can be slightly problematic.  Some
>> spiders such as googlebot actually put their URL in the User-Agent header,
>> as a semi-colon separated list, which is not ideal.  The user and the
>> user-agent are different concepts.  The proposed header would be a simpler
>> solution, imho.
>> >>>
>> >>>
>> >>> 'Just a hint' doesn't tell anyone what this is really going to be
>> used for. Are there use-cases written down, in addition to a syntax?
>> >>>
>> >>> The current text includes: "It SHOULD NOT be used as an insecure form
>> of access protection."  -- This is the same as the "From" header (which may
>> contain an email address).  Do you think stronger wording is required.
>> >>>
>> >>> The use case is the same as "From" in fact, my ideal would have been
>> just to loosen the scope of "From" but there was pushback from the IETF on
>> this, with the suggestion to think of another header name.
>> >>>
>> >>> In particular, one thing we are working on in the Read Write Web
>> Community Group is fine grained access control for writing or appending a
>> file.  It's helpful to know who is trying to make a change before returning
>> e.g. SUCCESS or FORBIDDEN response codes.
>> >>>
>> >>>
>> >>> On a more specific level, this looks like "On-behalf-of" - a more
>> indicative name than "user" for the seemingly potential usage (this request
>> is performed on behalf of the user X)?
>> >>>
>> >>> I'd be very happy to reuse something existing, so long as it allowed
>> URLs and email address too.  If I'm correct, On-behalf-of is email specific?
>> >>>
>> >>>
>> >>> I'm not sure why OpenIDs couldn't appear in this header, FWIW. The
>> recipient could run OpenID protocol with the client, regarding the
>> identifier sent in the header. That would allow "verification" of the
>> OpenID to occur, wouldn't it?
>> >>>
>> >>> Well I hadnt thought of that, but yes that could work quite well!
>>  One of the perceived issues with OpenID as a URL (dating back as far as
>> Yadis) was that the UX for typing in an HTTP URL lead to a loss of
>> conversions.  If this could be done by the software and may save some
>> typing, especially on mobile devices.  The same technique could be used
>> with PKI if the URL contained a public key and the (rich) client could
>> store the private key.  I think that will become a more valuable use case
>> next year when crypto on the browser becomes a REC
>> >>>
>> >>>
>> >>> John
>> >>>
>> >>> On Jul 17, 2013, at 7:41 PM, Melvin Carvalho <
>> melvincarvalho at gmail.com> wrote:
>> >>>
>> >>> >
>> >>> >
>> >>> >
>> >>> > On 18 July 2013 01:06, Nat Sakimura <sakimura at gmail.com> wrote:
>> >>> > Hi.
>> >>> >
>> >>> > I am forwarding the mail in the identity commons list.
>> >>> >
>> >>> > Apparently, there is an initiative at W3C proposing a new
>> "identity" header, which I believe is actually harmful for the general
>> public. Simple web sites are going to take it as authenticated identity and
>> thus will cause identity theft of their users.
>> >>> >
>> >>> > Their proposal is to include
>> >>> >
>> >>> >   User: http://this.is.the/user/identifier
>> >>> >
>> >>> > in the HTTP header.
>> >>> >
>> >>> > Could those of you active in W3C reach out to them?
>> >>> >
>> >>> > As I have written below, if it were to just include the IdP address
>> as a hint, I am kind of fine.
>> >>> >
>> >>> > Thanks for sharing this.  Since this was my proposal, I hope I can
>> shed a bit of light light.
>> >>> >
>> >>> > Firstly, it's not the W3C, simply a group of people brainstorming
>> in the a W3C hosted forum (aka community groups).  The proposal has no
>> official standing, but if there are no objections, the idea is to try and
>> push the idea upstream.
>> >>> >
>> >>> > Yes, the idea is that it is just a hint.  Note the text:
>> >>> >
>> >>> > "The client SHOULD NOT send the User header field without the
>> user's approval, as it might conflict with the user's privacy interests or
>> their site's security policy. It is strongly recommended that the user be
>> able to disable, enable, and modify the value of this field at any time
>> prior to a request."
>> >>> >
>> >>> > We asked the IETF if we could use the "From" header for this, but
>> the feedback is that "From" is restricted to email, and this would be
>> difficult to change.  The suggestion was to come up with a new header.
>>  Very happy to have feedback, I've followed IIW work for many years.
>> >>> >
>> >>> >
>> >>> > Best,
>> >>> >
>> >>> > Nat
>> >>> >
>> >>> > ---------- Forwarded message ----------
>> >>> > From: Kaliya "Identity Woman" <kaliya-lists at identitywoman.net>
>> >>> > Date: 2013/7/18
>> >>> > Subject: Re: [community] from W3C….Fwd: Proposal: "User" header
>> field
>> >>> > To: Nat Sakimura <sakimura at gmail.com>
>> >>> > Cc: "community at lists.idcommons.net" <community at lists.idcommons.net>
>> >>> >
>> >>> >
>> >>> > Yes Nat,  Thats sort of what I got from reading it.
>> >>> >
>> >>> > Who among us is very active in the W3C world?
>> >>> >
>> >>> > If no one should we be figuring out who should be?
>> >>> >
>> >>> > Should we write them a letter asking them to send "identitish"
>> proposals to IIW? or other forums for good input?
>> >>> >
>> >>> > Maybe we should write something that is like understanding identity
>> basics for technical specification folks across a range of standards bodies?
>> >>> >
>> >>> > - Kaliya
>> >>> >
>> >>> > On Jul 17, 2013, at 3:32 AM, Nat Sakimura wrote:
>> >>> >
>> >>> >> Whoa, what's that?!
>> >>> >>
>> >>> >> That's not only useless but actually harmful.
>> >>> >>
>> >>> >> I can kind of see some utility in sending the IdP address, but not
>> the user.
>> >>> >>
>> >>> >> =nat via iPhone
>> >>> >>
>> >>> >> On Jul 16, 2013, at 7:39, "Kaliya \"Identity Woman\"" <
>> kaliya-lists at identitywoman.net> wrote:
>> >>> >>
>> >>> >>> Hi folks,
>> >>> >>>  Apparently the W3C wants to send "user" names along in HTTP
>> headers.
>> >>> >>>   I thought some folks who know about identity and how it
>> does/could/should work might be up for chiming in over there.
>> >>> >>>   It seems like Authentication of identity might be a good thing
>> rather then just assertion.
>> >>> >>>  - Kaliya
>> >>> >>>
>> >>> >>>
>> >>> >>> Begin forwarded message:
>> >>> >>>
>> >>> >>>> From: Christine
>> >>> >>>
>> >>> >>>> As you know, I'm a big proponent of open standards. For this
>> reason I monitor many groups. You might be interested in the W3C Read Write
>> Web community group: http://www.w3.org/community/rww/
>> >>> >>>>
>> >>> >>>> I sent you a message a few weeks ago about Tabulator.
>> >>> >>>>
>> >>> >>>> See below messages about User header field. If you are not
>> already a member, I recommend you join and contribute!
>> >>> >>>>
>> >>> >>>> Christine
>> >>> >>>>
>> >>> >>>>
>> >>> >>>> -------- Original Message --------
>> >>> >>>> Subject:   Re: Proposal: "User" header field
>> >>> >>>> Resent-Date:       Sat, 13 Jul 2013 16:19:02 +0000
>> >>> >>>> Resent-From:       public-rww at w3.org
>> >>> >>>> Date:      Sat, 13 Jul 2013 12:08:37 -0400
>> >>> >>>> From:      Joe <presbrey at gmail.com>
>> >>> >>>> To:        Melvin Carvalho <melvincarvalho at gmail.com>
>> >>> >>>> CC:        public-rww <public-rww at w3.org>
>> >>> >>>>
>> >>> >>>> Great job Melvin!
>> >>> >>>>
>> >>> >>>> Data.fm sends the User header already :)
>> >>> >>>>
>> >>> >>>>
>> >>> >>>>
>> >>> >>>>
>> >>> >>>> On Jul 13, 2013, at 10:55 AM, Melvin Carvalho <
>> melvincarvalho at gmail.com> wrote:
>> >>> >>>>
>> >>> >>>>> I would be nice to be able to identify a user in HTTP,
>> especially with read/write protocols and access control, it can be
>> important to know who is trying to change something.
>> >>> >>>>>
>> >>> >>>>> There has been some discussion on whether the "From" header can
>> be used to identify a user in HTTP, and my from most people is that this
>> would be a good candidate to send a user, but for historical reasons it's
>> limited to email, and changing this would perhaps get some pushback from
>> the IETF.
>> >>> >>>>>
>> >>> >>>>> The suggestion has been to choose another header, so I thought
>> that "User" might be a good candidate, since we have User Agent arleady.
>> >>> >>>>>
>> >>> >>>>> Here's the proposed text:
>> >>> >>>>>
>> >>> >>>>> [[
>> >>> >>>>> User
>> >>> >>>>>
>> >>> >>>>> The User request-header field, if given, SHOULD contain an
>> identifier for the human user who controls the requesting user agent. The
>> address SHOULD be machine-usable, as defined by the "URI General Syntax"
>> RFC 3986
>> >>> >>>>>        User   = "User" ":" URI
>> >>> >>>>>
>> >>> >>>>> An example is:
>> >>> >>>>>
>> >>> >>>>>        User: http://www.w3.org/People/Berners-Lee/card#i
>> >>> >>>>> This header field MAY be used for logging purposes and as a
>> means for identifying the source of invalid or unwanted requests. It SHOULD
>> NOT be used as an insecure form of access protection. The interpretation of
>> this field is that the request is being performed on behalf of the person
>> given, who accepts responsibility for the method performed. In particular,
>> robot agents SHOULD include this header so that the person responsible for
>> running the robot can be contacted if problems occur on the receiving end.
>> >>> >>>>>
>> >>> >>>>>
>> >>> >>>>> The client SHOULD NOT send the User header field without the
>> user's approval, as it might conflict with the user's privacy interests or
>> their site's security policy. It is strongly recommended that the user be
>> able to disable, enable, and modify the value of this field at any time
>> prior to a request.
>> >>> >>>>>
>> >>> >>>>> ]]
>> >>> >>>>>
>> >>> >>>>> Feedback welcome!
>> >>> >>>>>
>> >>> >>>>
>> >>> >>>>
>> >>> >>>
>> >>> >>>
>> >>> >>> ____________________________________________________________
>> >>> >>> You received this message as a subscriber on the list:
>> >>> >>>     community at lists.idcommons.net
>> >>> >>> To be removed from the list, send any message to:
>> >>> >>>     community-unsubscribe at lists.idcommons.net
>> >>> >>>
>> >>> >>> For all list information and functions, see:
>> >>> >>>     http://lists.idcommons.net/lists/info/community
>> >>> >
>> >>> >
>> >>> >
>> >>> >
>> >>> > --
>> >>> > Nat Sakimura (=nat)
>> >>> > Chairman, OpenID Foundation
>> >>> > http://nat.sakimura.org/
>> >>> > @_nat_en
>> >>> >
>> >>> > _______________________________________________
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>> >>> > specs at lists.openid.net
>> >>> > http://lists.openid.net/mailman/listinfo/openid-specs
>> >>> >
>> >>> >
>> >>> > _______________________________________________
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>> >>> > specs at lists.openid.net
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>> >>>
>> >>>
>> >>>
>> >>>
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>> >>
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>> >>
>> >
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>>
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>
>
> --
> Nat Sakimura (=nat)
> Chairman, OpenID Foundation
> http://nat.sakimura.org/
> @_nat_en
>
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