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
