On Wed, Sep 04, 2019 at 06:17:32PM -0600, Brian Campbell wrote: > On Wed, Sep 4, 2019 at 5:55 PM Benjamin Kaduk <ka...@mit.edu> wrote: > > > On Wed, Sep 04, 2019 at 05:19:27PM -0600, Brian Campbell wrote: > > > Thanks Ben, for the review and non-objectional ballot. > > > > > > On Wed, Sep 4, 2019 at 3:13 PM Benjamin Kaduk via Datatracker < > > > nore...@ietf.org> wrote: > > > > > > > Benjamin Kaduk has entered the following ballot position for > > > > draft-ietf-oauth-resource-indicators-05: No Objection > > > > > > > > Section 3 > > > > > > > > An access token that is audience restricted to a protected resource > > > > that obtains that token legitimately cannot be used to access > > > > resources on behalf of the resource owner at other protected > > > > resources. The "resource" parameter enables a client to indicate > > the > > > > > > > > nit: This sentence has a pretty strange construction. I think the > > > > intent is to say that that a token, legitimately presented to a > > > > resource, cannot then be taken by that resource server and > > > > illegitimately present it somewhere else for access to other resources. > > > > But with the current wording we seem to be missing part of the part > > > > where some entity obtains the token with intent for illegitimate > > access. > > > > > > > > > > Yes, despite the pretty strange construction, you have the correct > > intent. > > > I'll work on improving that sentence (borrowing heavily from your words > > > there). > > > > > > > > > > > > > Some servers may host user content or be multi-tenant. In order to > > > > avoid attacks that might confuse a client into sending an access > > > > token to a resource that is user controlled or is owned by a > > > > different tenant, it is important to use a specific resource URI > > > > including a path component. This will cause any access token issued > > > > for accessing the user controlled resource to have an invalid > > > > audience if replayed against the legitimate resource API. > > > > > > > > I'm not entirely sure what this is trying to say. What is the > > > > "legitimate resource API"? Why would a token be issued for accessing a > > > > user-controlled resource if that's something we're trying to avoid > > > > having confused clients access? > > > > > > > > > > Um... so on rereading that I might say that it's also "pretty strange". > > > > > > What it was trying to somehow say is similar to the previous nit about > > > audience-restricted not being usable at the resource for whom the weren't > > > intended. But saying so in the context of a multi-tenant environment. > > > Basically it's trying to say that, in a multi-tenant environment, the > > > resource URI and subsequent token audience need to have something that > > > identifies the tenant so as to prevent the token from being used by one > > > tenant to illegitimately access resources at a different tenant. I'll > > work > > > on trying to improve that text to better explain all that. > > > > Ah, yes, that's a very good point to make. I'm happy to look at some draft > > text if you want. > > > > Thanks, here's what I've got now for this and the previous item in sec 3. > Suggestions welcome. > > 3. Security Considerations > > An audience-restricted access token, legitimately presented to a > resource, cannot then be taken by that resource to present it > elsewhere for illegitimate access to other resources. The "resource"
I think "by that resource and presented elsewhere" probbaly has a more parallel flow. > parameter enables a client to indicate the protected resources where > the requested access token will be used, which in turn enables the > authorization server to apply the appropriate audience restrictions > to the token. > > Some servers may host user content or be multi-tenant. In order to > avoid attacks where one tenant uses an access token to illegitimately > access resources owned by a different tenant, it is important to use > a specific resource URI including any portion of the URI that > identifies the tenant, such as a path component. This will allow > access tokens to be audience-restricted in a way that identifies the > tenant and prevent their use, due to an invalid audience, at > resources owned by a different tenant. But other than the above nit, this all looks really good; thank you! -Ben _______________________________________________ OAuth mailing list OAuth@ietf.org https://www.ietf.org/mailman/listinfo/oauth
