As an admin, you would configure login modules using standard JAAS
configuration. So, if you are supporting Kerberos and smart card login
modules within a single broker, in your jaas.conf you would specify:
KafkaServer {
com.ibm.security.auth.module.Krb5LoginModule required
credsType=both
useKeytab="file:/kafka/key.tab"
principal="kafka/localh...@example.com";
example.SmartcardLoginModule required
cardNumber=123
};
Since smart card logins are not built into Kafka (or the JDK), you need a
developer to build the login module. So the developer implements
example.SmartcardLoginModule. In addition, the developer may also implement
callback handlers for the SASL client or server and a login class to keep
this login refreshed. The callback handlers and login implementation
support all the mechanisms that the organisation supports - in this case
Kerberos and smart card.
As an admin, if you are using mechanisms built into Kafka, you simply
specify a JAAS config with the combination of mechanisms you want and you
are done. If you are adding new mechanisms, it clearly can't be done
without some additional code to implement that mechanism. The callback and
login interfaces are configurable to ensure that (as a developer), you can
build custom mechanisms without modifying Kafka. SASL was designed
precisely to do this. But at the moment, Kafka restricts what type of
authentication you can perform with SASL.
Back to the questions:
1. *How does the proposed Login class interact with LoginContext and *
*LoginModule.*
Login class performs *LoginContext.login(). *This performs login for all
the login modules of that context (this is standard Java function). Login
is cached with a reference counter to keep it alive.
2. *Do we really need a pluggable Login class, when users **(administrators,
not developers) are more likely to want to specify LoginModules?*
Administrators specify *LoginModules. *Developers implement new mechanisms.
The pluggable *Login* class enables the developer to implement new
mechanisms without changing Kafka. If Kafka didn't have a default Kerberos
implementation and a user wanted to use Kerberos, pluggability of *Login* class
enables the user to include Kerberos without changing Kafka. Not that we
want another Kerberos, but Tao had a requirement to enable a custom
mechanism with functionality similar to Kerberos (see KIP-44). Pluggable
*Login* supports this use case without replacing the entire authentication
mechanism in Kafka.
*3. How will users get to specify multiple LoginModules?*
Standard Java JAAS configuration - see example above.
*4. It sounds like different LoginModules may need
different CallbackHandlers. Since we only allow a single
pluggableCallbackHandler class in the KIP-43 configuration, how will this
be handled?*
One LoginContext, one subject, one callback handler, multiple login
modules. This is the Java model for login. And it works well because
callback handlers tend to be fairly standard. Even if the smart card SASL
callbacks needed to do something wildly different and you wanted a broker
that combined this with Kerberos, you would implement a callback that
looked like the code below.
private CallbackHandler handler;
public void configure(Map<String, ?> configs, Mode mode, Subject
subject, String mechanism) {public void configure(Map<String, ?> configs,
Mode mode, Subject subject, String mechanism) {
switch (mechanism) {
case "GSSAPI" : handler = new GssapiCallbackHandler(); break
;
case "SMARTCARD" : handler = new SmartcardCallbackHandler();
break;
}
}
public void handle(Callback[] callbacks) throws IOException,
UnsupportedCallbackException {
handler.handle(callbacks);
}
But I don't see this as just an admin configuration. This is some code
developed alongside a new mechanism. Yes, you can add a new configuration
type in Kafka that maps mechanism to callback handler class to avoid the
switch statement. But that doesn't remove the need for new code altogether
since you still need to implement SmartcardCallbackHandler. Multiple
conflicting callback handlers within one broker to support complete
different behaviour is an edge case. Since the design supports
full flexibility in terms of functionality and you have to write new code
for new mechanisms anyway, this feels like the simplest solution.
On Tue, Mar 8, 2016 at 8:23 PM, Gwen Shapira <g...@confluent.io> wrote:
> I guess what is unclear to me is:
>
> 1. How does the proposed Login class interact with LoginContext and
> LoginModule.
> 2. Do we really need a pluggable Login class, when users
> (administrators, not developers) are more likely to want to specify
> LoginModules?
> 3. How will users get to specify multiple LoginModules?
> 4. It sounds like different LoginModules may need different
> CallbackHandlers. Since we only allow a single pluggable
> CallbackHandler class in the KIP-43 configuration, how will this be
> handled?
>
> In other words, suppose I want my Kafka installation to support both
> Kerberos and SmartCard mechanisms, can you tell me how to configure
> Kafka? (as admin, not developer)?
>
> Gwen
>
>
>
> On Tue, Mar 8, 2016 at 11:46 AM, Rajini Sivaram
> <rajinisiva...@googlemail.com> wrote:
> > Gwen,
> >
> > I am not sure I understand your concern. Java login contexts support
> > multiple login modules precisely to support this type of real-world
> > scenario.
> >
> > From Javadoc of *javax.security.auth.login.LoginContext*:
> >
> > *In addition to supporting pluggable authentication, this class also
> > supports the notion of stacked authentication. Applications may be
> > configured to use more than one LoginModule. For example, one could
> > configure both a Kerberos LoginModule and a smart card LoginModule under
> an
> > application. *
> >
> > * A typical caller instantiates a LoginContext with a name and a
> > CallbackHandler. LoginContext uses the name as the index into a
> > Configuration to determine which LoginModules should be used, and which
> > ones must succeed in order for the overall authentication to succeed. The
> > CallbackHandler is passed to the underlying LoginModules so they may
> > communicate and interact with users (prompting for a username and
> password
> > via a graphical user interface, for example).*
> >
> > If it is good enough for Java, surely it must be good enough for Kafka.
> We
> > don't expect users to directly use existing classes when they want to
> > support complex new mechanisms. Login is not a standard interface, and we
> > want to make callback handlers configurable. So we do require users to
> wrap
> > their existing classes in our interface. And the interfaces make it
> > possible to plugin any number of mechanisms. Am I missing something?
> >
> >
> >
> > On Tue, Mar 8, 2016 at 4:49 PM, Gwen Shapira <g...@confluent.io> wrote:
> >
> >> Yes, I understand that.
> >>
> >> However, because the current configuration only allows a single
> >> callback and a single login module, I need to supply a class that
> >> supports callbacks or logins for every single mechanism that I need to
> >> support. I question whether this is applicable in real-world scenario
> >> where a user may need to support mechanisms that were written by
> >> different vendors and where a single class that implements all the
> >> necessary modules or callsbacks is very unlikely to exist.
> >>
> >> I agree that supporting a list of classes and dynamically using the
> >> correct callbacks and modules based on configuration is complex, but I
> >> don't think this feature is useful enough without it.
> >>
> >> Gwen
> >>
> >> On Tue, Mar 8, 2016 at 2:40 AM, Rajini Sivaram
> >> <rajinisiva...@googlemail.com> wrote:
> >> > Gwen,
> >> >
> >> > Sorry if this is not clear in the KIP. The goal of the KIP is to
> enable
> >> new
> >> > mechanisms to be added without any changes to Apache Kafka. The
> >> > configuration proposed by the KIP is based on the configurability of
> the
> >> > Java SASL API and what it would take to add a new mechanism similar to
> >> > Kerberos/PLAIN/Digest-MD5 and the requirements that Tao raised for
> custom
> >> > authentication.
> >> >
> >> > The PR includes a test for Digest-MD5 which is not included in Kafka,
> but
> >> > is tested using the configuration options that allow new mechanisms
> to be
> >> > added.
> >> >
> >> > If you want to add a more complex mechanism which requires integration
> >> with
> >> > some external authentication libraries for login or callback handlers,
> >> you
> >> > can do that by configuring your own callback handler and login
> >> > implementation. The login class allows you to add additional threads
> (for
> >> > instance for token refresh), while the callback handler extends the
> >> > standard Java CallbackHandler interface, enabling you to override any
> of
> >> > the default callbacks in Kafka to provide your own behaviour. If you
> want
> >> > to add your own login modules, SASL server or SASL client
> implementation
> >> > for a mechanism that is not supported in your JDK, you can do that by
> >> > adding new Java security modules, using the built-in pluggability of
> Java
> >> > security.
> >> >
> >> > And finally, if you want to enable multiple mechanisms in your Kafka
> >> > brokers, you can specify a callback handler class that either provides
> >> the
> >> > handlers for all the mechanisms (as the PR does for Kerberos and
> PLAIN)
> >> or
> >> > a delegator that calls different callback handlers based on the
> >> mechanism.
> >> > And for login, you provide a single or a compound class that provides
> any
> >> > additional login logic for all the login modules that you have
> specified
> >> > for KafkaServer.
> >> >
> >> > Hope that helps.
> >> >
> >> >
> >> > On Tue, Mar 8, 2016 at 1:17 AM, Gwen Shapira <g...@confluent.io>
> wrote:
> >> >
> >> >> Can you explain the process for a adding a new mechanism based on
> >> current
> >> >> KIP?
> >> >>
> >> >> My thought is that if it requires modifying Apache Kafka code, it is
> >> >> not pluggable enough.
> >> >>
> >> >> On Mon, Mar 7, 2016 at 4:04 PM, Rajini Sivaram
> >> >> <rajinisiva...@googlemail.com> wrote:
> >> >> > Gwen,
> >> >> >
> >> >> > In cases where you want completely different callbacks for
> different
> >> >> > mechanisms, I was thinking that the choice would be between a map
> of
> >> >> > classes (mechanism -> callbackHandler class) or a delegator class
> that
> >> >> > chooses the appropriate callback handler class based on mechanism.
> I
> >> >> chose
> >> >> > the latter since it makes it easier to configure in Kafka. Since we
> >> >> create
> >> >> > a callback handler for each channel and configure it with the
> >> >> > client-selected mechanism, it is straightforward to have one
> wrapper
> >> >> class
> >> >> > that delegates to the right mechanism-specific class to handle
> >> callbacks.
> >> >> > In many cases, a single class may be sufficient (the PR uses a
> single
> >> >> > callback class for Kerberos and PLAIN). I do see your point about
> the
> >> >> > flexibility that multiple classes would provide, but since you need
> >> to be
> >> >> > able to associate the callback with a mechanism for this to be
> >> useful, I
> >> >> am
> >> >> > not sure if just a list would add value.
> >> >> >
> >> >> > Login class is slightly different since the proposal is to use a
> >> single
> >> >> > login context with multiple login modules to handle multiple
> >> mechanisms.
> >> >> In
> >> >> > this case, you want to perform login for all the mechanisms that
> are
> >> >> > enabled. And you want to call loginContext.login() only once.
> Again,
> >> you
> >> >> > can delegate to multiple classes if you wish to add some complex
> >> >> > mechanism-specific logic, but a single login class makes the
> mapping
> >> to a
> >> >> > single login context and the login cache more obvious (the PR has a
> >> test
> >> >> > that includes Kerberos and PLAIN).
> >> >> >
> >> >> > Thoughts?
> >> >> >
> >> >> > On Mon, Mar 7, 2016 at 9:57 PM, Gwen Shapira <g...@confluent.io>
> >> wrote:
> >> >> >
> >> >> >> Hi,
> >> >> >>
> >> >> >> Before I can vote on this KIP, I have two additional questions /
> >> >> >> comments on the new configuration:
> >> >> >>
> >> >> >> 1. sasl.callback.handler.class - it looks like we want a single
> class
> >> >> >> that implements all mechanisms. I think this will make it
> difficult
> >> to
> >> >> >> extend since the only way I can add a mechanism will be by
> >> >> >> implementing every single existing mechanism (otherwise customers
> >> will
> >> >> >> need to choose between new and existing when selecting which
> class to
> >> >> >> use). If Microsoft releases a proprietary "AD Mechanism" and
> Oracle
> >> >> >> releases "OID mechanism", there will be no class that implements
> >> both.
> >> >> >> Can we make it a list of classes instead? I realize this
> complicates
> >> >> >> the code a bit (some kind of factory will be required to choose
> the
> >> >> >> right class to use), but important IMO.
> >> >> >> 2. similar for sasl.login.class - if I have a class for Kerberos
> >> (with
> >> >> >> refresh thread) and a class for "plain", we need to be able to
> load
> >> >> >> both.
> >> >> >>
> >> >> >> Gwen
> >> >> >>
> >> >> >> On Wed, Mar 2, 2016 at 12:30 AM, Rajini Sivaram
> >> >> >> <rajinisiva...@googlemail.com> wrote:
> >> >> >> > Jun,
> >> >> >> >
> >> >> >> > Thanks, I have added a note to the KIP. I will add a comment in
> the
> >> >> >> > implementation and also add a unit test to ensure that conflicts
> >> are
> >> >> >> > avoided when version number is modified.
> >> >> >> >
> >> >> >> > On Tue, Mar 1, 2016 at 5:43 PM, Jun Rao <j...@confluent.io>
> wrote:
> >> >> >> >
> >> >> >> >> Rajini,
> >> >> >> >>
> >> >> >> >> Thanks for the explanation. For 1, this implies that we have
> to be
> >> >> >> careful
> >> >> >> >> with changing the 2-byte version in the future to avoid
> conflict.
> >> >> Could
> >> >> >> you
> >> >> >> >> document this in the KIP and also in the implementation?
> >> >> >> >>
> >> >> >> >> Jun
> >> >> >> >>
> >> >> >> >> On Tue, Mar 1, 2016 at 2:47 AM, Rajini Sivaram <
> >> >> >> >> rajinisiva...@googlemail.com
> >> >> >> >> > wrote:
> >> >> >> >>
> >> >> >> >> > Jun,
> >> >> >> >> >
> >> >> >> >> > Thank you for the review.
> >> >> >> >> >
> >> >> >> >> >
> >> >> >> >> > 1. With GSSAPI, the first context establishment packet
> starts
> >> >> with
> >> >> >> the
> >> >> >> >> > byte 0x60 (tag for APPLICATION-0) followed by a
> >> variable-length
> >> >> >> >> encoded
> >> >> >> >> > size, followed by various tags and contents. And the
> packet
> >> also
> >> >> >> >> > contains a
> >> >> >> >> > checksum. This is completely different from the mechanism
> >> packet
> >> >> >> from
> >> >> >> >> > Kafka
> >> >> >> >> > clients which start with a two-byte version set to zero
> >> >> currently,
> >> >> >> >> > followed
> >> >> >> >> > by just a String mechanism.
> >> >> >> >> > 2. Agreed, I have removed the version from the server
> >> response
> >> >> in
> >> >> >> the
> >> >> >> >> > KIP. Thanks.
> >> >> >> >> >
> >> >> >> >> >
> >> >> >> >> > On Tue, Mar 1, 2016 at 2:33 AM, Jun Rao <j...@confluent.io>
> >> wrote:
> >> >> >> >> >
> >> >> >> >> > > Rajini,
> >> >> >> >> > >
> >> >> >> >> > > Thanks for the updates. Just a couple of minor comments.
> >> >> >> >> > >
> >> >> >> >> > > 1. With the default GSSAPI, what's the first packet that
> the
> >> >> client
> >> >> >> >> sends
> >> >> >> >> > > to the server? Is that completely different from the packet
> >> >> format
> >> >> >> that
> >> >> >> >> > we
> >> >> >> >> > > will use for non-GSSAPI mechanisms?
> >> >> >> >> > >
> >> >> >> >> > > 2. In the server response, it doesn't seem that we need to
> >> >> include
> >> >> >> the
> >> >> >> >> > > version since the client knows the version of the request
> >> that it
> >> >> >> >> sends.
> >> >> >> >> > >
> >> >> >> >> > > Jun
> >> >> >> >> > >
> >> >> >> >> > > On Mon, Feb 29, 2016 at 10:14 AM, Rajini Sivaram <
> >> >> >> >> > > rajinisiva...@googlemail.com> wrote:
> >> >> >> >> > >
> >> >> >> >> > > > Harsha,
> >> >> >> >> > > >
> >> >> >> >> > > > Thank you for the review. I will wait another day to see
> if
> >> >> there
> >> >> >> is
> >> >> >> >> > more
> >> >> >> >> > > > feedback and then start a voting thread.
> >> >> >> >> > > >
> >> >> >> >> > > > Rajini
> >> >> >> >> > > >
> >> >> >> >> > > > On Mon, Feb 29, 2016 at 2:51 PM, Harsha <ka...@harsha.io
> >
> >> >> wrote:
> >> >> >> >> > > >
> >> >> >> >> > > > > Rajini,
> >> >> >> >> > > > > Thanks for the changes to the KIP. It
> looks
> >> >> good
> >> >> >> to
> >> >> >> >> > me. I
> >> >> >> >> > > > > think we can move to voting.
> >> >> >> >> > > > > Thanks,
> >> >> >> >> > > > > Harsha
> >> >> >> >> > > > >
> >> >> >> >> > > > > On Mon, Feb 29, 2016, at 12:43 AM, Rajini Sivaram
> wrote:
> >> >> >> >> > > > > > I have added some more detail to the KIP based on the
> >> >> >> discussion
> >> >> >> >> in
> >> >> >> >> > > the
> >> >> >> >> > > > > > last KIP meeting to simplify support for multiple
> >> >> mechanisms.
> >> >> >> >> Have
> >> >> >> >> > > also
> >> >> >> >> > > > > > changed the property names to reflect this.
> >> >> >> >> > > > > >
> >> >> >> >> > > > > > Also updated the PR in
> >> >> >> >> > > > https://issues.apache.org/jira/browse/KAFKA-3149
> >> >> >> >> > > > > > to
> >> >> >> >> > > > > > reflect the KIP.
> >> >> >> >> > > > > >
> >> >> >> >> > > > > > Any feedback is appreciated.
> >> >> >> >> > > > > >
> >> >> >> >> > > > > >
> >> >> >> >> > > > > > On Tue, Feb 23, 2016 at 9:36 PM, Rajini Sivaram <
> >> >> >> >> > > > > > rajinisiva...@googlemail.com> wrote:
> >> >> >> >> > > > > >
> >> >> >> >> > > > > > > I have updated the KIP based on the discussion in
> the
> >> KIP
> >> >> >> >> meeting
> >> >> >> >> > > > > today.
> >> >> >> >> > > > > > >
> >> >> >> >> > > > > > > Comments and feedback are welcome.
> >> >> >> >> > > > > > >
> >> >> >> >> > > > > > > On Wed, Feb 3, 2016 at 7:20 PM, Rajini Sivaram <
> >> >> >> >> > > > > > > rajinisiva...@googlemail.com> wrote:
> >> >> >> >> > > > > > >
> >> >> >> >> > > > > > >> Hi Harsha,
> >> >> >> >> > > > > > >>
> >> >> >> >> > > > > > >> Thank you for the review. Can you clarify - I
> think
> >> you
> >> >> are
> >> >> >> >> > saying
> >> >> >> >> > > > > that
> >> >> >> >> > > > > > >> the client should send its mechanism over the
> wire to
> >> >> the
> >> >> >> >> > server.
> >> >> >> >> > > Is
> >> >> >> >> > > > > that
> >> >> >> >> > > > > > >> correct? The exchange is slightly different in the
> >> KIP
> >> >> >> (the PR
> >> >> >> >> > > > > matches the
> >> >> >> >> > > > > > >> KIP) from the one you described to enable
> >> >> interoperability
> >> >> >> >> with
> >> >> >> >> > > > > 0.9.0.0.
> >> >> >> >> > > > > > >>
> >> >> >> >> > > > > > >>
> >> >> >> >> > > > > > >> On Wed, Feb 3, 2016 at 1:56 PM, Harsha <
> >> m...@harsha.io>
> >> >> >> >> wrote:
> >> >> >> >> > > > > > >>
> >> >> >> >> > > > > > >>> Rajini,
> >> >> >> >> > > > > > >>> I looked at the PR you have. I think
> its
> >> >> better
> >> >> >> >> with
> >> >> >> >> > > > your
> >> >> >> >> > > > > > >>> earlier approach rather than extending
> >> the
> >> >> >> >> protocol.
> >> >> >> >> > > > > > >>> What I was thinking initially is, Broker has a
> >> config
> >> >> >> option
> >> >> >> >> of
> >> >> >> >> > > say
> >> >> >> >> > > > > > >>> sasl.mechanism = GSSAPI, PLAIN
> >> >> >> >> > > > > > >>> and the client can have similar config of
> >> >> >> >> sasl.mechanism=PLAIN.
> >> >> >> >> > > > > Client
> >> >> >> >> > > > > > >>> can send its sasl mechanism before the handshake
> >> starts
> >> >> >> and
> >> >> >> >> if
> >> >> >> >> > > the
> >> >> >> >> > > > > > >>> broker accepts that particular mechanism than it
> >> can go
> >> >> >> ahead
> >> >> >> >> > > with
> >> >> >> >> > > > > > >>> handshake otherwise return a error saying that
> the
> >> >> >> mechanism
> >> >> >> >> > not
> >> >> >> >> > > > > > >>> allowed.
> >> >> >> >> > > > > > >>>
> >> >> >> >> > > > > > >>> Thanks,
> >> >> >> >> > > > > > >>> Harsha
> >> >> >> >> > > > > > >>>
> >> >> >> >> > > > > > >>> On Wed, Feb 3, 2016, at 04:58 AM, Rajini Sivaram
> >> wrote:
> >> >> >> >> > > > > > >>> > A slightly different approach for supporting
> >> >> different
> >> >> >> SASL
> >> >> >> >> > > > > mechanisms
> >> >> >> >> > > > > > >>> > within a broker is to allow the same "*security
> >> >> >> protocol*"
> >> >> >> >> to
> >> >> >> >> > > be
> >> >> >> >> > > > > used
> >> >> >> >> > > > > > >>> on
> >> >> >> >> > > > > > >>> > different ports with different configuration
> >> >> options. An
> >> >> >> >> > > > advantage
> >> >> >> >> > > > > of
> >> >> >> >> > > > > > >>> > this
> >> >> >> >> > > > > > >>> > approach is that it extends the
> configurability of
> >> >> not
> >> >> >> just
> >> >> >> >> > > SASL,
> >> >> >> >> > > > > but
> >> >> >> >> > > > > > >>> any
> >> >> >> >> > > > > > >>> > protocol. For instance, it would enable the
> use of
> >> >> SSL
> >> >> >> with
> >> >> >> >> > > > mutual
> >> >> >> >> > > > > > >>> client
> >> >> >> >> > > > > > >>> > authentication on one port or different
> >> certificate
> >> >> >> chains
> >> >> >> >> on
> >> >> >> >> > > > > another.
> >> >> >> >> > > > > > >>> > And
> >> >> >> >> > > > > > >>> > it avoids the need for SASL mechanism
> negotiation.
> >> >> >> >> > > > > > >>> >
> >> >> >> >> > > > > > >>> > Kafka would have the same "*security protocols"
> >> >> >> *defined as
> >> >> >> >> > > > today,
> >> >> >> >> > > > > but
> >> >> >> >> > > > > > >>> > with
> >> >> >> >> > > > > > >>> > (a single) configurable SASL mechanism. To have
> >> >> >> different
> >> >> >> >> > > > > > >>> configurations
> >> >> >> >> > > > > > >>> > of
> >> >> >> >> > > > > > >>> > a protocol within a broker, users can define
> new
> >> >> >> protocol
> >> >> >> >> > names
> >> >> >> >> > > > > which
> >> >> >> >> > > > > > >>> are
> >> >> >> >> > > > > > >>> > configured versions of existing protocols,
> perhaps
> >> >> using
> >> >> >> >> just
> >> >> >> >> > > > > > >>> > configuration
> >> >> >> >> > > > > > >>> > entries and no additional code.
> >> >> >> >> > > > > > >>> >
> >> >> >> >> > > > > > >>> > For example:
> >> >> >> >> > > > > > >>> >
> >> >> >> >> > > > > > >>> > A single mechanism broker would be configured
> as:
> >> >> >> >> > > > > > >>> >
> >> >> >> >> > > > > > >>> > listeners=SASL_SSL://:9092
> >> >> >> >> > > > > > >>> > sasl.mechanism=GSSAPI
> >> >> >> >> > > > > > >>> > sasl.kerberos.class.name=kafka
> >> >> >> >> > > > > > >>> > ...
> >> >> >> >> > > > > > >>> >
> >> >> >> >> > > > > > >>> >
> >> >> >> >> > > > > > >>> > And a multi-mechanism broker would be
> configured
> >> as:
> >> >> >> >> > > > > > >>> >
> >> >> >> >> > > > > > >>> >
> >> listeners=gssapi://:9092,plain://:9093,custom://:9094
> >> >> >> >> > > > > > >>> > gssapi.security.protocol=SASL_SSL
> >> >> >> >> > > > > > >>> > gssapi.sasl.mechanism=GSSAPI
> >> >> >> >> > > > > > >>> > gssapi.sasl.kerberos.class.name=kafka
> >> >> >> >> > > > > > >>> > ...
> >> >> >> >> > > > > > >>> > plain.security.protocol=SASL_SSL
> >> >> >> >> > > > > > >>> > plain.sasl.mechanism=PLAIN
> >> >> >> >> > > > > > >>> > ..
> >> >> >> >> > > > > > >>> > custom.security.protocol=SASL_PLAINTEXT
> >> >> >> >> > > > > > >>> > custom.sasl.mechanism=CUSTOM
> >> >> >> >> > > > > > >>> >
> >> >> >> >> > >
> >> custom.sasl.callback.handler.class=example.CustomCallbackHandler
> >> >> >> >> > > > > > >>> >
> >> >> >> >> > > > > > >>> >
> >> >> >> >> > > > > > >>> >
> >> >> >> >> > > > > > >>> > This is still a big change because it affects
> the
> >> >> >> currently
> >> >> >> >> > > fixed
> >> >> >> >> > > > > > >>> > enumeration of security protocol definitions,
> but
> >> one
> >> >> >> that
> >> >> >> >> is
> >> >> >> >> > > > > perhaps
> >> >> >> >> > > > > > >>> > more
> >> >> >> >> > > > > > >>> > flexible than defining every new SASL mechanism
> >> as a
> >> >> new
> >> >> >> >> > > security
> >> >> >> >> > > > > > >>> > protocol.
> >> >> >> >> > > > > > >>> >
> >> >> >> >> > > > > > >>> > Thoughts?
> >> >> >> >> > > > > > >>> >
> >> >> >> >> > > > > > >>> >
> >> >> >> >> > > > > > >>> > On Tue, Feb 2, 2016 at 12:20 PM, Rajini
> Sivaram <
> >> >> >> >> > > > > > >>> > rajinisiva...@googlemail.com> wrote:
> >> >> >> >> > > > > > >>> >
> >> >> >> >> > > > > > >>> > > As Ismael has said, we do not have a
> >> requirement to
> >> >> >> >> support
> >> >> >> >> > > > > multiple
> >> >> >> >> > > > > > >>> > > protocols in a broker. But I agree with Jun's
> >> >> >> observation
> >> >> >> >> > > that
> >> >> >> >> > > > > some
> >> >> >> >> > > > > > >>> > > companies might want to support a different
> >> >> >> >> authentication
> >> >> >> >> > > > > mechanism
> >> >> >> >> > > > > > >>> for
> >> >> >> >> > > > > > >>> > > internal users or partners. For instance, we
> do
> >> use
> >> >> >> two
> >> >> >> >> > > > different
> >> >> >> >> > > > > > >>> > > authentication mechanisms, it just so happens
> >> that
> >> >> we
> >> >> >> are
> >> >> >> >> > > able
> >> >> >> >> > > > > to use
> >> >> >> >> > > > > > >>> > > certificate-based authentication for internal
> >> >> users,
> >> >> >> and
> >> >> >> >> > > hence
> >> >> >> >> > > > > don't
> >> >> >> >> > > > > > >>> > > require multiple SASL mechanisms in a broker.
> >> >> >> >> > > > > > >>> > >
> >> >> >> >> > > > > > >>> > > As Tao has pointed out, mechanism negotiation
> >> is a
> >> >> >> common
> >> >> >> >> > > usage
> >> >> >> >> > > > > > >>> pattern.
> >> >> >> >> > > > > > >>> > > Many existing protocols that support SASL do
> >> >> already
> >> >> >> use
> >> >> >> >> > this
> >> >> >> >> > > > > > >>> pattern. AMQP
> >> >> >> >> > > > > > >>> > > (
> >> >> >> >> > > > > > >>> > >
> >> >> >> >> > > > > > >>>
> >> >> >> >> > > > >
> >> >> >> >> > > >
> >> >> >> >> > >
> >> >> >> >> >
> >> >> >> >>
> >> >> >>
> >> >>
> >>
> http://docs.oasis-open.org/amqp/core/v1.0/os/amqp-core-security-v1.0-os.html#type-sasl-mechanisms
> >> >> >> >> > > > > > >>> ),
> >> >> >> >> > > > > > >>> > > which, as a messaging protocol maybe closer
> to
> >> >> Kafka
> >> >> >> in
> >> >> >> >> use
> >> >> >> >> > > > cases
> >> >> >> >> > > > > > >>> than
> >> >> >> >> > > > > > >>> > > Zookeeper, is an example. Other examples
> where
> >> the
> >> >> >> client
> >> >> >> >> > > > > negotiates
> >> >> >> >> > > > > > >>> or
> >> >> >> >> > > > > > >>> > > sends SASL mechanism to server include ACAP
> >> that is
> >> >> >> used
> >> >> >> >> as
> >> >> >> >> > > an
> >> >> >> >> > > > > > >>> example in
> >> >> >> >> > > > > > >>> > > the SASL RFCs, POP3, LDAP, SMTP etc. This is
> >> not to
> >> >> >> say
> >> >> >> >> > that
> >> >> >> >> > > > > Kafka
> >> >> >> >> > > > > > >>> > > shouldn't use a different type of mechanism
> >> >> selection
> >> >> >> >> that
> >> >> >> >> > > fits
> >> >> >> >> > > > > > >>> better with
> >> >> >> >> > > > > > >>> > > the existing Kafka design. Just that
> negotiation
> >> >> is a
> >> >> >> >> > common
> >> >> >> >> > > > > pattern
> >> >> >> >> > > > > > >>> and
> >> >> >> >> > > > > > >>> > > since we typically turn on javax.net.debug to
> >> debug
> >> >> >> TLS
> >> >> >> >> > > > > negotiation
> >> >> >> >> > > > > > >>> issues,
> >> >> >> >> > > > > > >>> > > having to use Kafka logging to debug SASL
> >> >> negotiation
> >> >> >> >> > issues
> >> >> >> >> > > is
> >> >> >> >> > > > > not
> >> >> >> >> > > > > > >>> that
> >> >> >> >> > > > > > >>> > > dissimilar.
> >> >> >> >> > > > > > >>> > >
> >> >> >> >> > > > > > >>> > >
> >> >> >> >> > > > > > >>> > > On Tue, Feb 2, 2016 at 6:12 AM, tao xiao <
> >> >> >> >> > > xiaotao...@gmail.com
> >> >> >> >> > > > >
> >> >> >> >> > > > > > >>> wrote:
> >> >> >> >> > > > > > >>> > >
> >> >> >> >> > > > > > >>> > >> I am the author of KIP-44. I hope my use
> case
> >> will
> >> >> >> add
> >> >> >> >> > some
> >> >> >> >> > > > > values
> >> >> >> >> > > > > > >>> to this
> >> >> >> >> > > > > > >>> > >> discussion. The reason I raised KIP44 is
> that I
> >> >> want
> >> >> >> to
> >> >> >> >> be
> >> >> >> >> > > > able
> >> >> >> >> > > > > to
> >> >> >> >> > > > > > >>> > >> implement a custom security protocol that
> can
> >> >> fulfill
> >> >> >> >> the
> >> >> >> >> > > need
> >> >> >> >> > > > > of my
> >> >> >> >> > > > > > >>> > >> company. As pointed out by Ismael KIP-43 now
> >> >> >> supports a
> >> >> >> >> > > > > pluggable
> >> >> >> >> > > > > > >>> way to
> >> >> >> >> > > > > > >>> > >> inject custom security provider to SASL I
> think
> >> >> it is
> >> >> >> >> > enough
> >> >> >> >> > > > to
> >> >> >> >> > > > > > >>> cover the
> >> >> >> >> > > > > > >>> > >> use case I have and address the concerns
> >> raised in
> >> >> >> >> KIP-44.
> >> >> >> >> > > > > > >>> > >>
> >> >> >> >> > > > > > >>> > >> For multiple security protocols support
> >> >> >> simultaneously
> >> >> >> >> it
> >> >> >> >> > is
> >> >> >> >> > > > not
> >> >> >> >> > > > > > >>> needed in
> >> >> >> >> > > > > > >>> > >> my use case and I don't foresee it is
> needed in
> >> >> the
> >> >> >> >> future
> >> >> >> >> > > but
> >> >> >> >> > > > > as i
> >> >> >> >> > > > > > >>> said
> >> >> >> >> > > > > > >>> > >> this is my use case only there may be other
> use
> >> >> cases
> >> >> >> >> that
> >> >> >> >> > > > need
> >> >> >> >> > > > > it.
> >> >> >> >> > > > > > >>> But if
> >> >> >> >> > > > > > >>> > >> we want to support it in the future I
> prefer to
> >> >> get
> >> >> >> it
> >> >> >> >> > right
> >> >> >> >> > > > at
> >> >> >> >> > > > > the
> >> >> >> >> > > > > > >>> first
> >> >> >> >> > > > > > >>> > >> place given the fact that security protocol
> is
> >> an
> >> >> >> ENUM
> >> >> >> >> and
> >> >> >> >> > > if
> >> >> >> >> > > > we
> >> >> >> >> > > > > > >>> stick to
> >> >> >> >> > > > > > >>> > >> that implementation it is very hard to
> extend
> >> in
> >> >> the
> >> >> >> >> > future
> >> >> >> >> > > > > when we
> >> >> >> >> > > > > > >>> decide
> >> >> >> >> > > > > > >>> > >> multiple security protocols is needed.
> >> >> >> >> > > > > > >>> > >>
> >> >> >> >> > > > > > >>> > >> Protocol negotiation is a very common usage
> >> >> pattern
> >> >> >> in
> >> >> >> >> > > > security
> >> >> >> >> > > > > > >>> domain. As
> >> >> >> >> > > > > > >>> > >> suggested in Java SASL doc
> >> >> >> >> > > > > > >>> > >>
> >> >> >> >> > > > > > >>> > >>
> >> >> >> >> > > > > > >>>
> >> >> >> >> > > > >
> >> >> >> >> > > >
> >> >> >> >> > >
> >> >> >> >> >
> >> >> >> >>
> >> >> >>
> >> >>
> >>
> http://docs.oracle.com/javase/7/docs/technotes/guides/security/sasl/sasl-refguide.html
> >> >> >> >> > > > > > >>> > >> client
> >> >> >> >> > > > > > >>> > >> first sends out a packet to server and
> server
> >> >> >> responds
> >> >> >> >> > with
> >> >> >> >> > > a
> >> >> >> >> > > > > list
> >> >> >> >> > > > > > >>> of
> >> >> >> >> > > > > > >>> > >> mechanisms it supports. This is very
> similar to
> >> >> >> SSL/TLS
> >> >> >> >> > > > > negotiation.
> >> >> >> >> > > > > > >>> > >>
> >> >> >> >> > > > > > >>> > >> On Tue, 2 Feb 2016 at 06:39 Ismael Juma <
> >> >> >> >> > ism...@juma.me.uk>
> >> >> >> >> > > > > wrote:
> >> >> >> >> > > > > > >>> > >>
> >> >> >> >> > > > > > >>> > >> > On Mon, Feb 1, 2016 at 7:04 PM, Gwen
> Shapira
> >> <
> >> >> >> >> > > > > g...@confluent.io>
> >> >> >> >> > > > > > >>> wrote:
> >> >> >> >> > > > > > >>> > >> >
> >> >> >> >> > > > > > >>> > >> > > Looking at "existing solutions", it
> looks
> >> like
> >> >> >> >> > Zookeeper
> >> >> >> >> > > > > allows
> >> >> >> >> > > > > > >>> > >> plugging
> >> >> >> >> > > > > > >>> > >> > in
> >> >> >> >> > > > > > >>> > >> > > any SASL mechanism, but the server will
> >> only
> >> >> >> support
> >> >> >> >> > one
> >> >> >> >> > > > > > >>> mechanism at
> >> >> >> >> > > > > > >>> > >> a
> >> >> >> >> > > > > > >>> > >> > > time.
> >> >> >> >> > > > > > >>> > >> > >
> >> >> >> >> > > > > > >>> > >> >
> >> >> >> >> > > > > > >>> > >> > This was the original proposal from
> Rajini as
> >> >> that
> >> >> >> is
> >> >> >> >> > > enough
> >> >> >> >> > > > > for
> >> >> >> >> > > > > > >>> their
> >> >> >> >> > > > > > >>> > >> > needs.
> >> >> >> >> > > > > > >>> > >> >
> >> >> >> >> > > > > > >>> > >> >
> >> >> >> >> > > > > > >>> > >> > > If this is good enough for our use-case
> >> (do we
> >> >> >> >> > actually
> >> >> >> >> > > > > need to
> >> >> >> >> > > > > > >>> > >> support
> >> >> >> >> > > > > > >>> > >> > > multiple mechanisms at once?), it will
> >> >> simplify
> >> >> >> >> life a
> >> >> >> >> > > lot
> >> >> >> >> > > > > for
> >> >> >> >> > > > > > >>> us (
> >> >> >> >> > > > > > >>> > >> > >
> >> >> >> >> > > > > > >>> > >>
> >> >> >> >> > > > > > >>>
> >> >> >> >> > > > >
> >> >> >> >> > >
> >> >> >> >>
> >> >> >>
> >> >>
> >>
> https://cwiki.apache.org/confluence/display/ZOOKEEPER/Zookeeper+and+SASL
> >> >> >> >> > > > > > >>> > >> > )
> >> >> >> >> > > > > > >>> > >> > >
> >> >> >> >> > > > > > >>> > >> >
> >> >> >> >> > > > > > >>> > >> > The current thinking is that it would be
> >> useful
> >> >> to
> >> >> >> >> > support
> >> >> >> >> > > > > > >>> multiple SASL
> >> >> >> >> > > > > > >>> > >> > mechanisms simultaneously. In the KIP
> >> meeting,
> >> >> Jun
> >> >> >> >> > > mentioned
> >> >> >> >> > > > > that
> >> >> >> >> > > > > > >>> > >> companies
> >> >> >> >> > > > > > >>> > >> > sometimes support additional
> authentication
> >> >> >> mechanisms
> >> >> >> >> > for
> >> >> >> >> > > > > > >>> partners, for
> >> >> >> >> > > > > > >>> > >> > example. It does make things more
> complex, as
> >> >> you
> >> >> >> say,
> >> >> >> >> > so
> >> >> >> >> > > we
> >> >> >> >> > > > > need
> >> >> >> >> > > > > > >>> to be
> >> >> >> >> > > > > > >>> > >> > sure the complexity is worth it.
> >> >> >> >> > > > > > >>> > >> >
> >> >> >> >> > > > > > >>> > >> > Two more points:
> >> >> >> >> > > > > > >>> > >> >
> >> >> >> >> > > > > > >>> > >> > 1. It has been suggested that custom
> security
> >> >> >> protocol
> >> >> >> >> > > > > support is
> >> >> >> >> > > > > > >>> > >> needed by
> >> >> >> >> > > > > > >>> > >> > some (KIP-44). Rajini enhanced KIP-43 so
> >> that a
> >> >> >> SASL
> >> >> >> >> > > > mechanism
> >> >> >> >> > > > > > >>> with a
> >> >> >> >> > > > > > >>> > >> > custom provider can be used for this
> purpose
> >> >> >> instead.
> >> >> >> >> > > Given
> >> >> >> >> > > > > this,
> >> >> >> >> > > > > > >>> it
> >> >> >> >> > > > > > >>> > >> seems
> >> >> >> >> > > > > > >>> > >> > a bit inconsistent and restrictive not to
> >> allow
> >> >> >> >> multiple
> >> >> >> >> > > > SASL
> >> >> >> >> > > > > > >>> mechanisms
> >> >> >> >> > > > > > >>> > >> > simultaneously (we do allow SSL and SASL
> >> >> >> >> authentication
> >> >> >> >> > > > > > >>> simultaneously,
> >> >> >> >> > > > > > >>> > >> > after all).
> >> >> >> >> > > > > > >>> > >> >
> >> >> >> >> > > > > > >>> > >> > 2. The other option would be to support a
> >> single
> >> >> >> SASL
> >> >> >> >> > > > > mechanism
> >> >> >> >> > > > > > >>> > >> > simultaneously to start with and then
> extend
> >> >> this
> >> >> >> to
> >> >> >> >> > > > multiple
> >> >> >> >> > > > > > >>> mechanisms
> >> >> >> >> > > > > > >>> > >> > simultaneously later (if and when
> needed). It
> >> >> seems
> >> >> >> >> like
> >> >> >> >> > > it
> >> >> >> >> > > > > would
> >> >> >> >> > > > > > >>> be
> >> >> >> >> > > > > > >>> > >> harder
> >> >> >> >> > > > > > >>> > >> > to support the latter in the future if we
> go
> >> >> down
> >> >> >> this
> >> >> >> >> > > > route,
> >> >> >> >> > > > > but
> >> >> >> >> > > > > > >>> maybe
> >> >> >> >> > > > > > >>> > >> > there are ways around this.
> >> >> >> >> > > > > > >>> > >> >
> >> >> >> >> > > > > > >>> > >> > Thoughts?
> >> >> >> >> > > > > > >>> > >> >
> >> >> >> >> > > > > > >>> > >> > Ismael
> >> >> >> >> > > > > > >>> > >> >
> >> >> >> >> > > > > > >>> > >>
> >> >> >> >> > > > > > >>> > >
> >> >> >> >> > > > > > >>> > >
> >> >> >> >> > > > > > >>> > >
> >> >> >> >> > > > > > >>> > > --
> >> >> >> >> > > > > > >>> > > Regards,
> >> >> >> >> > > > > > >>> > >
> >> >> >> >> > > > > > >>> > > Rajini
> >> >> >> >> > > > > > >>> > >
> >> >> >> >> > > > > > >>> >
> >> >> >> >> > > > > > >>> >
> >> >> >> >> > > > > > >>> >
> >> >> >> >> > > > > > >>> > --
> >> >> >> >> > > > > > >>> > Regards,
> >> >> >> >> > > > > > >>> >
> >> >> >> >> > > > > > >>> > Rajini
> >> >> >> >> > > > > > >>>
> >> >> >> >> > > > > > >>
> >> >> >> >> > > > > > >>
> >> >> >> >> > > > > > >>
> >> >> >> >> > > > > > >> --
> >> >> >> >> > > > > > >> Regards,
> >> >> >> >> > > > > > >>
> >> >> >> >> > > > > > >> Rajini
> >> >> >> >> > > > > > >>
> >> >> >> >> > > > > > >
> >> >> >> >> > > > > > >
> >> >> >> >> > > > > > >
> >> >> >> >> > > > > > > --
> >> >> >> >> > > > > > > Regards,
> >> >> >> >> > > > > > >
> >> >> >> >> > > > > > > Rajini
> >> >> >> >> > > > > > >
> >> >> >> >> > > > > >
> >> >> >> >> > > > > >
> >> >> >> >> > > > > >
> >> >> >> >> > > > > > --
> >> >> >> >> > > > > > Regards,
> >> >> >> >> > > > > >
> >> >> >> >> > > > > > Rajini
> >> >> >> >> > > > >
> >> >> >> >> > > >
> >> >> >> >> > > >
> >> >> >> >> > > >
> >> >> >> >> > > > --
> >> >> >> >> > > > Regards,
> >> >> >> >> > > >
> >> >> >> >> > > > Rajini
> >> >> >> >> > > >
> >> >> >> >> > >
> >> >> >> >> >
> >> >> >> >> >
> >> >> >> >> >
> >> >> >> >> > --
> >> >> >> >> > Regards,
> >> >> >> >> >
> >> >> >> >> > Rajini
> >> >> >> >> >
> >> >> >> >>
> >> >> >> >
> >> >> >> >
> >> >> >> >
> >> >> >> > --
> >> >> >> > Regards,
> >> >> >> >
> >> >> >> > Rajini
> >> >> >>
> >> >> >
> >> >> >
> >> >> >
> >> >> > --
> >> >> > Regards,
> >> >> >
> >> >> > Rajini
> >> >>
> >> >
> >> >
> >> >
> >> > --
> >> > Regards,
> >> >
> >> > Rajini
> >>
> >
> >
> >
> > --
> > Regards,
> >
> > Rajini
>
--
Regards,
Rajini
