Hi Mayuresh,
To clarify, the intention is to use the KafkaPrincipal object built by the
KafkaPrincipalBuilder inside the Session. So we would remove the logic to
construct a new KafkaPrincipal using only the name from the Principal. Then
it should be possible to pass the `AuthzPrincipal` to the underlying
library through the `Extended_Plugged_In_Class` as you've suggested above.
Is that reasonable for this use case?
Thanks,
Jason
On Fri, Aug 25, 2017 at 2:44 PM, Mayuresh Gharat <gharatmayures...@gmail.com
> wrote:
> Hi Jason,
>
> Thanks for the replies.
>
> I think it would be better to discuss with an example that we were trying
> to address with KIP-111 and see if the current mentioned solution would
> address it.
>
> Let's consider a third party library called authz_lib that is provided by
> some Security team at some company.
>
> - When we call authz_lib.createPrincipal(X509_cert), it would return an
> AuthzPrincipal that implements Java.Security.Principal.
>
>
> - The authz_lib also provides an checkAccess(....) call that takes in 3
> parameters :
> - authz_principal
> - operation type ("Read", "Write"...)
> - resource (for simplicity lets consider it as a TopicName)
>
>
> - The AuthzPrincipal looks like this :
>
> class AuthzPrincipal implements java.security.Principal
> {
> String name;
> String field1;
> Object field2;
> Object field3;
> .....//Some third party logic......
> }
>
>
> - In PrincipalBuilder.buildPrincipal() would return AuthzPrincipal as
> follows :
>
> public Principal buildPrincipal(...)
> {
> ......
> X509Certificate x509Cert = session.getCert(..);
> return authz_lib.createPrincipal(x509Cert);
> }
>
>
> - The custom Authorizer (lets call it CustomAuthzAuthorizer), we would
> use the checkAccess() function provided by the authz_lib as follows :
>
> public class CustomAuthzAuthorizer implements Authorizer
> {
> .........
> public boolean authorize(.....)
> {
> AuthzPrincipal authz_principal = (AuthzPrincipal)
> session.getPrincipal();
> return authz_lib.checkAccess(authz_principal, "Read", "topicX");
> }
> ..........
> }
>
>
> - The issue with current implementation is that in
> processCompletedReceives() in SocketServer we create a KafkaPrincipal
> that just extracts the name from AuthzPrincipal as follows :
>
> session = RequestChannel.Session(new
> KafkaPrincipal(KafkaPrincipal.USER_TYPE,
> *openOrClosingChannel.principal.getName*),
> openOrClosingChannel.socketAddress)
>
> So the "AuthzPrincipal authz_principal = (AuthzPrincipal)
> session.getPrincipal()" call in the CustomAuthzAuthorizer would error
> out because we are trying to cast a KafkaPrincipal to AuthzPrincipal.
>
>
>
> In your reply when you said that :
>
> The KIP says that a user can have a class that extends KafkaPrincipal.
> Would this extended class be used when constructing the Session object
> in the SocketServer instead of constructing a new KafkaPrincipal?
>
> Yes, that's correct. We want to allow the authorizer to be able to leverage
> > additional information from the authentication layer.
>
>
> Would it make sense to make this extended class pluggable and when
> constructing the Session object in SocketServer check if a plugin is
> defined and use it and if not use the default KafkaPrincipal something like
> :
>
> if (getConfig("principal.pluggedIn.class").isDefined())
> //"principal.pluggedIn.class"
> is just an example name for the config
> {
> session = RequestChannel.Session(*Extended_Plugged_In_Class*,
> openOrClosingChannel.socketAddress)
> }
> else
> {
> session = RequestChannel.Session(new KafkaPrincipal(KafkaPrincipal.
> USER_TYPE,
> *openOrClosingChannel.principal.getName*),
> openOrClosingChannel.socketAddress)
> }
>
> This would solve the issue above as follows :
>
> We can have something like :
> public class Extended_Plugged_In_Class extends KafkaPrincipal
> {
> AuthzPrincipal authzPrincipal;
>
> public Extended_Plugged_In_Class(....., AuthzPrincipal principal)
> {
> super(...);
> authzPrincipal = principal;
>
> }
>
> ......
>
> public AuthzPrincipal getAuthzPrincipal()
> {
> return authzPrincipal;
> }
> }
>
> In the CustomAuthzAuthorizer we could do something like :
>
> public class CustomAuthzAuthorizer implements Authorizer
> {
> .........
> public boolean authorize(.....)
> {
> Extended_Plugged_In_Class extended_Kafka_Principal =
> (Extended_Plugged_In_Class)
> session.getPrincipal();
> AuthzPrincipal authz_principal =
> extended_Kafka_Principal.getAuthzPrincipal();
> return authz_lib.checkAccess(authz_principal, "Read", "topicX");
> }
> ..........
> }
>
>
> Thanks,
>
> Mayuresh
>
> On Fri, Aug 25, 2017 at 11:53 AM, Jason Gustafson <ja...@confluent.io>
> wrote:
>
> > Hey Mayuresh,
> >
> > Thanks for the comments.
> >
> > - The KIP says that a user can have a class that extends
> KafkaPrincipal.
> > > Would this extended class be used when constructing the Session
> object
> > > in
> > > the SocketServer instead of constructing a new KafkaPrincipal?
> >
> >
> > Yes, that's correct. We want to allow the authorizer to be able to
> leverage
> > additional information from the authentication layer.
> >
> > - The KIP says "A principal is always identifiable by a principal
> type
> > > and a name. Nothing else should ever be required." This might not be
> > > true
> > > always, right? For example, we might have a custom third party ACL
> > > library
> > > that creates a custom Principal from the passed in cert (this is
> done
> > in
> > > PrincipalBuilder/KafkaPrincipalBuilder) and the custom Authorizer
> > might
> > > use this third party library to authorize using this custom
> Principal
> > > object. The developer who is implementing the Kafka Authorizer
> should
> > > not be caring about what the custom Principal would look like and
> its
> > > details, since it will just pass it to the third party library in
> > Kafka
> > > Authorizer's authorize() call.
> >
> >
> > I'm not sure I understand this. Are you saying that the authorizer and
> > principal builder are implemented by separate individuals? If the
> > authorizer doesn't understand how to identify the principal, then it
> > wouldn't work, right? Maybe I'm missing something?
> >
> > Let me explain how I see this. The simple ACL authorizer that Kafka ships
> > with understands user principals as consisting of a type and a name. Any
> > principal builder that follows this assumption will work with the
> > SimpleAclAuthorizer. In some cases, the principal builder may provide
> > additional metadata in a KafkaPrincipal extension such as user groups or
> > roles. This information is not needed to identify the user principal, so
> > the builder is still compatible with the SimpleAclAuthorizer. It would
> also
> > be compatible with a RoleBasedAuthorizer which understood how to use the
> > role metadata provided by the KafkaPrincipal extension. Basically what we
> > would have is a user principal which is related to one or more role
> > principals through the KafkaPrincipal extension. Both user and role
> > principals are identifiable with a type and a name, so the ACL command
> tool
> > can then be used (perhaps with a custom authorizer) to define permissions
> > in either case.
> >
> > On the other hand, if a user principal is identified by more than just
> its
> > name, then it is not compatible with the SimpleAclAuthorizer. This
> doesn't
> > necessarily rule out this use case. As long as the authorizer and the
> > principal builder both agree on how user principals are identified, then
> > they can still be used together. But I am explicitly leaving out support
> in
> > the ACL command tool for this use case in this KIP. This is mostly about
> > clarifying what is compatible with the authorization system that Kafka
> > ships with. Of course we can always reconsider it in the future.
> >
> > Thanks,
> > Jason
> >
> > On Fri, Aug 25, 2017 at 10:48 AM, Mayuresh Gharat <
> > gharatmayures...@gmail.com> wrote:
> >
> > > Hi Jason,
> > >
> > > Thanks a lot for the KIP and sorry for the delayed response.
> > >
> > > I had a few questions :
> > >
> > >
> > > - The KIP says that a user can have a class that extends
> > KafkaPrincipal.
> > > Would this extended class be used when constructing the Session
> object
> > > in
> > > the SocketServer instead of constructing a new KafkaPrincipal?
> > >
> > >
> > > - The KIP says "A principal is always identifiable by a principal
> type
> > > and a name. Nothing else should ever be required." This might not be
> > > true
> > > always, right? For example, we might have a custom third party ACL
> > > library
> > > that creates a custom Principal from the passed in cert (this is
> done
> > in
> > > PrincipalBuilder/KafkaPrincipalBuilder) and the custom Authorizer
> > might
> > > use this third party library to authorize using this custom
> Principal
> > > object. The developer who is implementing the Kafka Authorizer
> should
> > > not be caring about what the custom Principal would look like and
> its
> > > details, since it will just pass it to the third party library in
> > Kafka
> > > Authorizer's authorize() call.
> > >
> > >
> > > Thanks,
> > >
> > > Mayuresh
> > >
> > >
> > > On Thu, Aug 24, 2017 at 10:21 AM, Mayuresh Gharat <
> > > gharatmayures...@gmail.com> wrote:
> > >
> > > > Sure.
> > > >
> > > > Thanks,
> > > >
> > > > Mayuresh
> > > >
> > > > On Wed, Aug 23, 2017 at 5:07 PM, Jun Rao <j...@confluent.io> wrote:
> > > >
> > > >> Hi, Mayuresh,
> > > >>
> > > >> Since this KIP covers the requirement in KIP-111, could you review
> it
> > > too?
> > > >>
> > > >> Thanks,
> > > >>
> > > >> Jun
> > > >>
> > > >>
> > > >> On Tue, Aug 22, 2017 at 3:04 PM, Jason Gustafson <
> ja...@confluent.io>
> > > >> wrote:
> > > >>
> > > >>> Bump. I'll open a vote in a few days if there are no comments.
> > > >>>
> > > >>> Thanks,
> > > >>> Jason
> > > >>>
> > > >>> On Sat, Aug 19, 2017 at 12:28 AM, Ismael Juma <ism...@juma.me.uk>
> > > wrote:
> > > >>>
> > > >>> > Thanks for the KIP Jason. It seems reasonable and cleans up some
> > > >>> > inconsistencies in that area. It would be great to get some
> > feedback
> > > >>> from
> > > >>> > Mayuresh and others who worked on KIP-111.
> > > >>> >
> > > >>> > Ismael
> > > >>> >
> > > >>> > On Thu, Aug 17, 2017 at 1:21 AM, Jason Gustafson <
> > ja...@confluent.io
> > > >
> > > >>> > wrote:
> > > >>> >
> > > >>> > > Hi All,
> > > >>> > >
> > > >>> > > I've added a new KIP to improve and extend the principal
> building
> > > API
> > > >>> > that
> > > >>> > > Kafka exposes:
> > > >>> > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-
> > > >>> > > 189%3A+Improve+principal+builder+interface+and+add+
> > > support+for+SASL
> > > >>> > > .
> > > >>> > >
> > > >>> > > As always, feedback is appreciated.
> > > >>> > >
> > > >>> > > Thanks,
> > > >>> > > Jason
> > > >>> > >
> > > >>> >
> > > >>>
> > > >>
> > > >>
> > > >
> > > >
> > > > --
> > > > -Regards,
> > > > Mayuresh R. Gharat
> > > > (862) 250-7125
> > > >
> > >
> > >
> > >
> > > --
> > > -Regards,
> > > Mayuresh R. Gharat
> > > (862) 250-7125
> > >
> >
>
>
>
> --
> -Regards,
> Mayuresh R. Gharat
> (862) 250-7125
>
