code review request: 6894072: always refresh keytab

[Weijun Wang]

Hi Valerie

Updated again:

http://cr.openjdk.java.net/~weijun/6894072/webrev.04/

1. KeyTab can be used by anyone
2. The two compatibility support

As for adding keys (from keytab) into private credentials set, I haven't 
cleaned up old ones. Since it's a set, this means if old keys are 
removed from the keytab, they stay in the set. The set is never really 
used by our code, so I think it's harmless. I really don't know how to 
clean up. Remove all keys for this principal? But we do this because we 
want to keep compatibility and worry about people directly manipulating 
the set, and I cannot predict what they will do with the set.

Thanks
Max


On 04/01/2011 10:23 AM, Weijun Wang wrote:
>
>
> On 04/01/2011 10:09 AM, Valerie (Yu-Ching) Peng wrote:
>> Max,
>>
>> I like this new approach of yours better.
>> As for compatibility, you mentioned only one aspect, i.e. apps which put
>> KerberosKeys inside a subject's private cred set.
>> There is also a possibility that apps may read the subject's private
>> credentials set for KerberosKeys that we used to put in and they won't
>> find the keys anymore since it's the KeyTab objects that we put into the
>> private cred set after this dynamic keytab support. Thoughts?
>
> No, I haven't thought about it.
>
> We can put a snapshot of keys there at the beginning and refresh them
> whenever a getKeys() is called. This should be harmless because we don't
> really use the keys if keytab objects (not keytab files) exist. I can do
> that.
>
> Thanks
> Max
>
>
>>
>> Valerie
>>
>>
>> On 03/31/11 03:41 AM, Weijun Wang wrote:
>>> Hi Valerie
>>>
>>> Sorry for the late reply. I've considered some alternatives.
>>>
>>> A "to-be-resolved" KerberosKey is quite difficult. When it's resolved,
>>> we have a list of keys with different etypes as the private
>>> credentials. If it's not resolved, we can only create one, whose
>>> encoding and etype are both unresolved, and when it finally gets
>>> resolved, it's resolved into multiple keys. Also, there was a simple
>>> mapping between KerberosKey and EncryptionKey. The resolving process
>>> is not always at the same time as the mapping (converting from one to
>>> another) time, so it seems EncryptionKey might also needs to be
>>> unresolved.
>>>
>>> Another solution is to revert back to my original KeyTab without an
>>> intended user. This means several changes:
>>>
>>> In my latest version of ServiceCreds, there were multiple keys and
>>> *one* keytab, now we also need multiple keytabs, because there might
>>> be multiple keytabs in the subject's private credentials set and we
>>> cannot tell which is for who. Therefore we collect all of them, when
>>> the keys are needed at AP-REP time, we call getKeys() on all of them,
>>> and return the combination. Hopefully there won't be two keys for the
>>> same principal with same kvno and same etype. I regard that as an abuse.
>>>
>>> Currently when there is no serverPrincipal specified in the
>>> Krb5AcceptCredential construction, we pick a KerberosKey from the
>>> private credentials set and use the KerberosPrincipal info inside, and
>>> then get all KerberosKeys for the same principal. We have never really
>>> looked at any KerberosPrincipal objects in the subject's principal
>>> set. I had tried to do the same to KeyTabs in my webrev.02. Now this
>>> will have a big change: the first step is always finding a
>>> KerberosPrincipal in the principal sets first. If serverPrincipal is
>>> specified, we find a matched one, otherwise, we just pick one and use
>>> it. And then, from the private credentials set, we fetch all
>>> KerberosKeys for this principal and all KeyTabs.
>>>
>>> I think this is the correct way to go. Of course, for compatibility
>>> reason, we assume there are third party codes that put KerberosKeys
>>> inside a subject's private credentials set but hasn't put any
>>> KerberosPrincipal there. Our Krb5LoginModule will never do it, but we
>>> can accept it.
>>>
>>> Here is a partial webrev:
>>>
>>> http://cr.openjdk.java.net/~weijun/6894072/webrev.03
>>>
>>> It only contains changes for Krb5Util.java, and hasn't included the
>>> compatibility codes I mentioned above. As you can see, the KeyTab
>>> objects are now retrieved by
>>>
>>> + sc.ktabs = SubjectComber.findMany(
>>> + subj, null, null, KeyTab.class);
>>>
>>> so no principal name is used, and we retrive "many".
>>>
>>> If you think this is OK, I'll clean up other codes. One benefit is
>>> that we don't need to update CCC with this solution. Yes we do
>>> introduce new hashCode/equals/toString methods, but I think they do
>>> not deserve a CCC.
>>>
>>> Thanks
>>> Max
>>>
>>>
>>> On 03/26/2011 08:20 AM, Valerie (Yu-Ching) Peng wrote:
>>>> Max,
>>>>
>>>> Well, I find it a bit awkward that the KeyTab class has to have the
>>>> KerberosPrincipal info which "intends" to use it.
>>>> Have you considered a different approach like:
>>>> Instead of adding the whole KeyTab object into the Subject's private
>>>> credential set, we add a "to-be-resolved" KerberosKey object. When we
>>>> need to use this kind of key, we'd check the associated KeyTab
>>>> object to
>>>> re-fresh its value if needed. This approach is conceptually closer to
>>>> what we had and the changes aren't as dramatic and seems to meet the
>>>> need required by 6894072.
>>>>
>>>> I'll continue to review your webrev, but just want to kick this idea
>>>> off
>>>> w/ you and see if it may work.
>>>> Valerie
>>>>
>>>> On 03/23/11 02:00 AM, Weijun Wang wrote:
>>>>> Hi Valerie
>>>>>
>>>>> Updated webrev:
>>>>>
>>>>> http://cr.openjdk.java.net/~weijun/6894072/webrev.02
>>>>>
>>>>> Changes since last version:
>>>>>
>>>>> 1. A KerberosPrincipal inside javax..KeyTab class. New getInstance()
>>>>> arguments, new getPrincipal() method.
>>>>>
>>>>> It can only be non-null now, but I didn't say anything in the spec.
>>>>> I'm hoping it can be null in the future to support multiple service
>>>>> principal in a single service.
>>>>>
>>>>> 2. toString(), hashCode(), equals() for KeyTab, since it will be put
>>>>> inside private credentials set.
>>>>>
>>>>> 3. Enhancement to SubjectComber:
>>>>> a) Generics for find() and findMany()
>>>>> b) findAux() now support Krb5AcceptCredential
>>>>>
>>>>> 4. Krb5Util.ServiceCreds: since principal is already inside both
>>>>> KeyTab and KerberosKey, no more KerberosPrincipal argument in
>>>>> getInstance(), there is still a field inside to save the value.
>>>>>
>>>>> 5. sun..KeyTab and javax..KeyTab: isMissing==true is now valid.
>>>>> Changes to the javadoc of javax..KeyTab.getKeys().
>>>>>
>>>>> 6. New TwoPrinces.java test, a subject with 2 KerberosPrincipal after
>>>>> JAAS commit.
>>>>>
>>>>> This time I'd like to first make sure implementation is correct, and
>>>>> then I'll update the CCC. Is this OK?
>>>>>
>>>>> Thanks
>>>>> Max
>>>>
>>