Hi all, I'm Kai and a guy from Intel Big Data team. I have been working on Apache Hadoop for some while, and used to be an ApacheDS contributor and committed the feature of CredentialCahce and a simple Kinit tool, guided by Emmanuel and Kiran. After that when I was going to implement more Kerberos features I realized there needs important improvement space in the existing fundamental Kerberos codes. As a prototype I initiated Haox project and have implemented an ASN1 encoding/decoding framework, complete encryption and checksum crypto, Kerberos codec, Keytab and CredentialCache facilities, KrbClient API and simple KDC server. It's still in its initial phase and far from ideal. However as strongly suggested by Emmanuel and Kiran, I should collaborate with ApacheDS community and continue to make the effort with you together. It's great and now I'm going to contribute the project to ApacheDS. I have discussed with Emmanuel and Kiran for quite some time about this. Based on our discussion, we have the following proposal. It's for your review and consider. Please kindly provide your feedback and advise. Thanks in advance.
1. First all our vision for the long term, we would think it makes great sense to establish a first class Kerberos implementation in Java for the Apache world targeting today's environments in cloud, Hadoop and mobile. Therefore we could collaborate together in ApacheDS community to build a "Apache Kerberos" project. That's why we're here. 2. And as the first step to start with, ApacheDS would accept Haox as a sub-project, renamed as "Apache Kerberos". Then we consolidate existing Kerberos implementation codes in ApacheDS into the new project; 3. Afterwards we will make further effort to push "Apache Kerberos" out as a top level project, probably in a year or so. We have discussed other approaches, like using the good stuffs in Haox to replace the corresponding parts in ApacheDS Kerberos, as one may also suggest. So let's figure out what might be good parts implemented in Haox. 1. Haox-ASN1. It's a schema/model driven ASN1 parser and codec. Based on the framework new Kerberos types can be easily defined following fixed patterns, without having to take care of ASN1 encoding/decoding procedures. We see this as very important because Kerberos itself and related extensions are very ASN1 heavy. Without the basic friendly library support it's hard for new developers to contribute on new Kerberos evolving features. We tested the codec performance and it outperforms a little. Emmanuel has even contributed a few optimization improvements. 2. Kerberos crypto. The crypto framework (based on RFC3961) and library implement all the encryption types and checksum types that MIT Kerberos supports, like DES, DES3, AES, RC4, CAMELLIA, with extensive interoperable tests covered. It relies on JCE for encryption but not any Kerberos facilities provided in JRE. Potentially we could port it to other non-Oracle Java environment like Android system, assuming we can implement corresponding encryption and hash providers which can be pluggable. 3. Kerberos codec. Based on Haox-Asn1, the codec has implemented all the necessary Kerberos types defined in Krb5(RFC4210), Preauth/FAST(RFC6113), and PKINIT(4556). The core part has some test cases covered already. 4. KDC server. The implementation abstracts an KrbIdentityService API and decouples any specific identity backend from the Kerberos server. We can provide an LDAP based backend, or allow vendor to implement their own backed by SQL database, external LDAP server or whatever. For simple unit test usage, a memory HashMap is all the needs. This allows our embedded KDC really very lightweight avoiding many unnecessary dependencies. 5. Haox-event. It implements a UDP/TCP mixed network event support based on Java NIO and reactor pattern according to Kerberos's needs, where UDP and TCP are both required, and even in IAKERB, a KDC proxy would serve both TCP server role and UDP/TCP client role. In Haox-event, all these roles can be done in an unified event receiving, processing and replying. Test cases are given but it definitely need to tune and improve. Again, it doesn't rely on any other libraries, thus based on it KrbClient could easily be supported in other Java environment. Keeping our long term goal in mind, we thought above functionalities, properties and considerations may serve better to establish the foundation for "Apache Kerberos" project, and it would be much easier to consolidate the existing Kerberos implementation into it. So as a first step for the collaboration, how about: 1. Prepare, which involves: 1) Necessary cleanup; 2) All Kerberos related codes will start package names with "org.apache.kerberos", all the non-Kerberos related codes will be moved into contrib projects or libraries, like Haox-ASN1, Haox-event, Haox-config, which are actually not Kerberos logic specific. 2. Move Haox to be an ApacheDS sub-project: 1) Renaming Haox as "Apache Kerberos"; 2) A separate GIT repo; 3) A separate coding style, subject to be discussed and determined. Then as the 2nd step, consolidate the necessary parts in existing Kerberos implementation. Below is the initial list and please complement: 1. Apache Directory Server support. We need to create an LdapIdentityBackend using Apache Directory Server and use it by default, embedded in the KDC server. 2. Installation packaging and service wrapper. Haox hasn't implemented such but ApacheDS does. 3. Tests. All the Kerberos related tests should be evaluated and ported to the new codebase if not obsolete. In addition to above, we also need to consider the following aspects, to make it good enough for potential users. 1. Adding the missing Javadoc. 2. Adding more tests. 3. Adding the documentation. 4. Building the web site With such done, then we might obsolete the AacheDS Kerberos implementation and might move all the related codes into an history folder for existing users. We would encourage users to use the new project. For the 3rd step, we would continue to implement some essential and advanced features, which may include: 1. Cross realm support, which means Apache Kerberos can federate with MIT Kerberos or MS AD; 2. Full functional client tools, like kinit, klist and kadmin, or other alternatives; 3. Preauth/FAST framework, which allows to support other authentication mechanisms based on the secure channel protected by an Armor TGT/key; 4. PKINIT, authenticating user using x509 certificate other than plain password; 5. Token preauth, authenticating user using a JWT token, to support OAuth. 6. ... Note tasks in step2 and 3 are not necessarily to be done in the order. We're likely to work on them in parallel. We would encourage more developers to contribute to the effort and develop the community. Without that, we may not be able to make it to have a high quality of Kerberos implementation, with all the important Kerberos feature gaps being filled. Then finally as the last step, in some appropriate time we would push Apache Kerberos out to be an Apache top level project. All the points are just suggestions and subject to your discussion. Your feedback is most welcome. As widely discussed in a week or so, this proposal is to be finalized and then re-posted. Then let's collaborate and make it together. Thanks for your support. Below is Haox project. https://github.com/drankye/haox At last but not least, many thanks to Emmanuel and Kiran. I can't appreciate them anymore. Without their encouraging, I would not have the motivation though it's still far away from the long term goal of "a first class Kerberos implementation". I do believe the Java world needs such, and the whole Apache world needs it as well. Thanks for your great questions, suggestions, complement points to sort this out. Thanks for helping me understand further about the Apache way, particularly regarding how I should proceed and collaborate with you guys in the community. Thank you all. Regards, Kai
