Prateek, I believe that here it is the SAML IdP that acts as OAuth
Client, not SAML SP - the point of the flow is to get the Assertion
(that the IDP would normally send through the browser) over to the SP
through an OAuth request/response exchange (in order to get an OAuth token)
paul
On 04/08/2010 11:08 AM, Prateek Mishra wrote:
Brian,
it would probably help to clarify that you are proposing this as a
additional or follow-on step to SSO implemented via the SAML web
browser profiles (right?).
Maybe some text could be added to the draft to make that explicit.
This is in contrast to more general token exchange scenarios - here
are bunch of SAML /XYZ tokens, now give me an OAuth token for for a
certain purpose. I agree with you that the latter would require quite
a bit of additional work.
Here is my understanding of the current use-case -
The user delivers a SAML bearer token (issued at an IdP) via a browser
profile to an SP. The SP, performs some business service for the user
and at some point
requires access to user resources at the IdP or at some third-party
site. Switching to OAuth terminology, the Client (SP) exchanges the
said SAML bearer token to the Authorization server (could be at the
IdP - this would be a common case I think) for an OAuth token. This is
the exchange you are describing in your draft.
Once the client obtains the OAuth token, it can bind it to a request
for the user resource.
I have some mild SAMology concerns about this - historically the SAML
bearer token has been constrained to have a short life-time and the
general advice is not to forward it beyond the SP. I am aware that in
practice this isnt the case - often the token is bound to some
subsequent flows - somewhat along the lines you are proposing. I will
follow up with these concerns on the SAML list.
- prateek
Seems like a much more complicated scenario. Allowing more than one
assertion, off the top of my head, would necessitate some major
changes to this profile:
* Define how multiple assertions are encoded into the single
"assertion" form control (samlp:Response, concatenated, something
else?)
* Deal with subject equality across the assertions
* Define the processing rules for multiple assertion (from different
issuers) and the expected behavior when some but not all are valid.
That seems like it would add significant complexity to the existing
draft (that I'm trying to keep simple) for a particular scenario that
I'm not sure is very common. But maybe I'm wrong. Is this something
that others anticipate needing? If so, does it belong here?
On Mon, Aug 2, 2010 at 4:26 PM, Anthony Nadalin
<tony...@microsoft.com> wrote:
So the scenario we have is where there are multiple tokens from
attribute and identity providers need to be delivered to an OAuth
authorization server to satisfy the resource owner's policy of
required claims. So this is a case where a single SAML
token/assertion is not enough to satisfy the claim, we still expect
that the signature verification is out of scope.
-----Original Message-----
From: oauth-boun...@ietf.org [mailto:oauth-boun...@ietf.org] On
Behalf Of Brian Campbell
Sent: Monday, August 02, 2010 2:53 PM
To: oauth
Subject: Re: [OAUTH-WG] SAML 2.0 Bearer Assertion Profile for OAuth
2.0 draft
I guess I'd need to understand the scenario better before I'd have an
opinion one way or the other. However, I will say that In this
profile I was specifically looking to avoid the complexity that
exists in SAML Web SSO by allowing for multiple assertions and
multiple subject confirmations.
On Mon, Aug 2, 2010 at 3:20 PM, Anthony Nadalin
<tony...@microsoft.com> wrote:
There are many cases where we need to have more than 1 SAML
assertion be used to represent the authorization token, so would
want a provision for multiple SAML tokens and not sure it makes
sense to have a separate profile for that or add it as an option here.
-----Original Message-----
From: oauth-boun...@ietf.org [mailto:oauth-boun...@ietf.org] On Behalf
Of Brian Campbell
Sent: Thursday, July 15, 2010 1:50 PM
To: oauth
Subject: [OAUTH-WG] SAML 2.0 Bearer Assertion Profile for OAuth 2.0
draft
I'm gong to join the growing list of people attaching a potential I-D
to an email due to he cut off time for the I-D submissions. Attached
is a draft that aims to tightly define the particular format of a SAML
2.0 bearer assertion in requesting an access token using the assertion
grant_type. I've been working with Chuck at Salesforce.com on this
and the primary goal is to have some documentation or specification
that is sufficient to facilitate interoperability between
independently developed implementations or products. This, of
course, wouldn't preclude using SAML in other ways - it would only
provide one concrete definition to implement against.
I intend to submit this as an I-D when the submission process reopens.
Any feedback from this group would be appreciated as well as
thoughts about this eventually becoming a working group draft.
Thanks,
Brian Campbell
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