[OAUTH-WG] Pete Resnick's No Objection on draft-ietf-oauth-assertions-17: (with COMMENT)

["Pete Resnick" <[e-mail]>]

Pete Resnick has entered the following ballot position for
draft-ietf-oauth-assertions-17: No Objection

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COMMENT:
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3 -

   Assertions used in the protocol exchanges defined by this
   specification MUST always be protected against tampering using a
   digital signature or a keyed message digest applied by the issuer.

Why is that? Aren't you using assertions over a protected channel (as
required by the spec) and therefore not need to sign the assertions?
Indeed, why would a self-issued Bearer Assertion need to be signed at
all? Does that even make sense?

4.1 -

   grant_type
      REQUIRED.  The format of the assertion as defined by the
      authorization server.  The value MUST be an absolute URI.

That MUST is unnecessary. It's just definitional from 6749, 4.5 (which,
as it happens, doesn't use 2119 language for this). s/MUST/will

   assertion
      REQUIRED.  The assertion being used as an authorization grant.
      Specific serialization of the assertion is defined by profile
      documents.  The serialization MUST be encoded for transport within
      HTTP forms.  It is RECOMMENDED that base64url be used.

The MUST seems weird here. Are you saying that the profile could not
possibly have a serialization for an assertion that did not require
further encoding? But the RECOMMENDED seems downright wrong: Either an
implementer *needs* to know the encoding independently of the profile,
and therefore this needs to be a MUST, or the profile is going to
describe the encoding, which could be base64url or could be something
else, and the implementation will do whatever the profile says. If you
really want to say something here, I suggest replacing the last two
sentences with:

      If the assertion is going to be transported within HTTP forms, the
      profile document needs to describe what (if any) encoding will be
      needed to do so. The base64url encoding is widely implemented and
      therefore suggested.
    
    scope
    [...]
                                                   As such, the
      requested scope MUST be equal or lesser than the scope originally
      granted to the authorized accessor.
      
s/MUST/will (unless you explain whether it's the server or the client
that's supposed to be obeying that MUST, and for what reason)
      
      If the scope parameter and/or
      value are omitted, the scope MUST be treated as equal to the scope
      originally granted to the authorized accessor.  The Authorization
      Server MUST limit the scope of the issued access token to be equal
      or lesser than the scope originally granted to the authorized
      accessor.

In the first sentence, is this MUST for the server? (That is, shouldn't
it be, "If the scope parameter and/or value are omitted, the server MUST
use the value of the scope originally granted to the authorized
accessor."?) And anyway, don't these two sentences contradict 6749, which
says:

   The authorization server MAY fully or partially ignore the scope
   requested by the client, based on the authorization server policy or
   the resource owner's instructions.
   [...]
   If the client omits the scope parameter when requesting
   authorization, the authorization server MUST either process the
   request using a pre-defined default value or fail the request
   indicating an invalid scope.

Here and throughout: s/non-normative example/example (As far as I know,
there are no other kinds in IETF documents.)

4.1.1 - s/MUST construct/constructs

4.2, client_assertion_type and client_assertion: See comments from 4.1
regarding grant_type and assertion.

4.2.1 - s/MUST construct/constructs

5.2 -

s/MUST identify/identifies

For clarification:
OLD
      Assertions that do
      not identify the Authorization Server as an intended audience MUST
      be rejected.
NEW
      The Authorization Server MUST reject any assertion that does not
      contain the its own identity as the intended audience.
END