Hi all,
my prioritization is driven by the goal to make OAuth the
authorization framework of choice for any internet standard protocol,
such as WebDAV, IMAP, SMTP or SIP. So let me first explain what is
missing from my point of view and explain some thoughts how to fill
the gaps.
A standard protocol is defined in terms of resource types and messages
by a body (e.g. IETF, OIDF, OMA), (hopefully) implemented in many
places, and used by different but deployment-independent clients.
OAuth-based protocol specifications must also define scope values
(e.g. read, write, send) and their relation to the resource types and
messages. The different deployments expose the standard protocol on
different resource server endpoints. In my opinion, it is fundamental
to clearly distinguish scope values (standardized, static) and
resource server addresses (deployment specific) and to manage their
relationships. The current scope definition is much to weak and
insufficient. Probably, the UMA concepts of hosts, resources sets, and
corresponding scopes could be adopted for that purpose.
OAuth today requires clients to register with the service provider
before they are deployed. Would you really expect IMAP clients, e.g.
Thunderbird, to register with any a-Mail services upfront? So clients
should be given a way to register dynamically to the authorization
servers. This should also allow us to cover "client instance" aspects.
It is interesting to note, that such a mechanism would allow us to get
rid of secret-less clients and the one-time usage requirement for
authorization codes.
We also assume the client to know the URLs of the resource server and
the corresponding authorization server and to use HTTPS server
authentication to verify the resource server's authenticity. This is
impossible in the standard scenario. Clients must be able to discover
the authorization server a particular resource server relies on at
runtime. The discovery mechanism could be specified by the OAuth WG,
but could also be part of an application protocols specification. But
we MUST find another way to prevent token phishing by counterfeit
resource servers.
As one approach, the client could pass the (previously HTTPS
validated) resource server's URL with the authorization request. The
authorization server should then refuse such requests for any unknown
(counterfeit) resource servers. Such an additional parameter could
also serve as namespace for scope values and enable service providers
to run multiple instances of the same service within a single
deployment.
If the additional data enlarges the request payload to much, we could
consider to adopt the "request by reference" proposal.
Let's now assume, OAuth is successful in the world of standard
protocols and we will see plenty of deployments with a bunch of
different OAuth protected resource servers. Shall this servers all be
accessible with a single token? In my opinion, this would cause
security, privacy and/or scalability/performance problems. To give
just the most obvious example, the target audience of such a token
cannot be restricted enough, which may allow a resource server (or an
attacker in control of it) to abuse the token on other servers. But
the current design of the code grant type forces deployments to use
the same token for all services. What is needed from my point of view
is a way to request and issue multiple server-specific access tokens
with a single authorization process.
I've been advocating this topic for a long time now and I'm still
convinced this is required to really complete the core design. We at
Deutsche Telekom needed and implemented this function on top of the
existing core. In my opinion, a core enhancement would be easier to
handle and more powerful. If others support this topic, I would be
willed to submit an I-D describing a possible solution.
If we take standards really seriously, then service providers should
be given the opportunity to implement their service by utilizing
standard server implementations. This creates the challenge to find a
standardized protocol between authorization server and resource server
to exchange authorization data. Depending on the token design
(self-contained vs. handle) this could be solved by either
standardizing a token format (JWT) or an authorization API.
Based on the rationale given above, my list is as follows (topics w/o
I-D are marked with *):
- Revocation (low hanging fruit since I-D is ready and implemented in
some places)
- Resource server notion*
- Multiple access tokens*
- Dynamic client registration
1) Dynamic Client Registration Protocol
4) Client Instance Extension
- Discovery
(10) Simple Web Discovery, probably other specs as well
- (6) JSON Web Token
- (7) JSON Web Token (JWT) Bearer Profile
- 8) User Experience Extension
- Device flow
- 9) Request by Reference
(depending resource server notion and multiple access tokens)
regards,
Torsten.
Zitat von Hannes Tschofenig <hannes.tschofe...@gmx.net>:
Hi all,
in preparation of the upcoming IETF meeting Barry and I would like
to start a re-chartering discussion. We both are currently
attending the Internet Identity Workshop and so we had the chance to
solicit input from the participants. This should serve as a
discussion starter.
Potential future OAuth charter items (in random order):
----------------
1) Dynamic Client Registration Protocol
Available document:
http://datatracker.ietf.org/doc/draft-hardjono-oauth-dynreg/
2) Token Revocation
Available document:
http://datatracker.ietf.org/doc/draft-lodderstedt-oauth-revocation/
3) UMA
Available document:
http://datatracker.ietf.org/doc/draft-hardjono-oauth-umacore/
4) Client Instance Extension
Available document:
http://tools.ietf.org/id/draft-richer-oauth-instance-00.txt
5) XML Encoding
Available document:
http://tools.ietf.org/id/draft-richer-oauth-xml-00.txt
6) JSON Web Token
Available document:
http://tools.ietf.org/html/draft-jones-json-web-token-05
7) JSON Web Token (JWT) Bearer Profile
Available document:
http://tools.ietf.org/html/draft-jones-oauth-jwt-bearer-00
8) User Experience Extension
Available document:
http://tools.ietf.org/html/draft-recordon-oauth-v2-ux-00
9) Request by Reference
Available document:
http://tools.ietf.org/html/draft-sakimura-oauth-requrl-00
10) Simple Web Discovery
Available document:
http://tools.ietf.org/html/draft-jones-simple-web-discovery-00
----------------
We have the following questions:
a) Are you interested in any of the above-listed items? (as a
reviewer, co-author, implementer, or someone who would like to
deploy). It is also useful to know if you think that we shouldn't
work on a specific item.
b) Are there other items you would like to see the group working on?
Note: In case your document is expired please re-submit it.
Ciao
Hannes & Barry
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