Mayuresh,
Thanks for the write up. With principal builder,
the idea is to reuse a single principal builder
across all the security protocols where its
applicable and given that principal builder has
access to transportLayer and authenticator it
should be able to figure out what type of
transportLayer it is and it should be able
construct the principal based on that and it should
handle all the security protocols that we support.
In your options 1,2 & 4 seems to be doing the same
thing i.e checking what security protocol that a
given transportLayer is and building a principal ,
correct me if I am wrong here. I like going with 4
as others stated on PR . As passing
security_protocol makes it more specific to the
method that its need to be handled . In the interest
of having less config I think option 4 seems to be
better even though it breaks the interface.
Thanks,
Harsha
On Fri, May 20, 2016, at 05:00 PM, Mayuresh Gharat wrote:
> Hi All,
>
> I came across an issue with plugging in a custom PrincipalBuilder class
> using the config "principal.builder.class" along with a custom Authorizer
> class using the config "authorizer.class.name".
>
> Consider the following scenario :
>
> For PlainText we don't supply any PrincipalBuilder. For SSL we want to
> supply a PrincipalBuilder using the property "principal.builder.class".
>
> a) Now consider we have a broker running on these 2 ports and supply that
> custom principalBuilder class using that config.
>
> b) The interbroker communication is using PlainText. I am using a single
> broker cluster for testing.
>
> c) Now we issue a produce request on the SSL port of the broker.
>
> d) The controller tries to build a channel for plaintext with this broker
> for the new topic instructions.
>
> e) PlainText tries to use the principal builder specified in the
> "principal.builder.class" config which was meant only for SSL port since
> the code path is same "ChannelBuilders.createPrincipalBuilder(configs)".
>
> f) In the custom principal Builder if we are trying to do some cert
> checks
> or down conversion of transportLayer to SSLTransportLayer so that we can
> use its functionality we get error/exception at runtime.
>
> The basic idea is the PlainText channel should not be using the
> PrincipalBuilder meant for other types of channels.
>
> Now there are few options/workarounds to avoid this :
>
> 1) Do instanceOf check in Authorizer.authorize() on TransportLayer
> instance
> passed in and do the correct handling. This is not intuitive and imposes
> a
> strict coding rule on the programmer.
>
> 2) TransportLayer should expose an API for telling the security protocol
> type. This is not too intuitive either.
>
> 3) Add extra configs for Authorizer and PrincipalBuilder for each channel
> type. This gives us a flexibility for the PrincipalBuilder and Authorizer
> handle requests on different types of ports in a different way.
>
> 4) PrincipalBuilder.buildPrincipal() should take in extra parameter for
> the
> type of protocol and we should document this in javadoc to use it to
> handle
> the type of request. This is little better than 1) and 2) but again
> imposes
> a strict coding rule on the programmer.
>
> Just wanted to know what the community thinks about this and get any
> suggestions/feedback . There's some discussion about this here :
> https://github.com/apache/kafka/pull/1403
>
> Thanks,
>
> Mayuresh
