Code review request, 8020842 IDN do not throw IAE when hostname ends with a trailing dot

[Michael McMahon]

I don't see how this fixes the original problem as the SNIHostName spec
still doesn't like hostnames with a trailing '.'

I'd prefer to check first where that requirement is coming from, if it is
actually necessary, and if not consider removing it from SNIHostName.
If it is necessary, then the check should be implemented in SNIHostName.

Michael

On 09/08/13 05:28, Xuelei Fan wrote:
> Thanks for your feedback and suggestions.
>
> Here is the new webrev:
>     http://cr.openjdk.java.net/~xuelei/8020842/webrev.02/
>
> "." is regarded as valid IDN in this update.
>
> Thanks,
> Xuelei
>
> On 8/9/2013 10:50 AM, Xuelei Fan wrote:
>> On 8/9/2013 10:14 AM, Weijun Wang wrote:
>>>
>>> On 8/9/13 9:37 AM, Xuelei Fan wrote:
>>>> On 8/9/2013 9:22 AM, Weijun Wang wrote:
>>>>> I tried nslookup. Those with ".." inside are illegal,
>>>>>
>>>>> $ nslookup com..
>>>>> nslookup: 'com..' is not a legal name (empty label)
>>>>>
>>>>> but
>>>>>
>>>>> $ nslookup .
>>>>> Server:        192.168.10.1
>>>>> Address:    192.168.10.1#53
>>>>>
>>>>> Non-authoritative answer:
>>>>> *** Can't find .: No answer
>>>>>
>>>> Thanks for the testing.  The behaviors are the same as this fix now.
>>> No exactly. It seems nslookup still regards "." legal but just cannot
>>> find an IP for it.
>>>
>> I'm not sure whether a root domain name can be stand alone.  Root label
>> is not considered as a label in IDN.  I think it is safe to regard that
>> "." is not a valid IDN as it contains no label.  Anyway, it is a corner
>> case.
>>
>> There are many online IDN conversion web services, some of them can
>> convert ".", some of the cannot.  In the present implementation, we
>> cannot recognize ".", and IDN.toASCII(".") throws
>> StringIndexOutOfBoundsException.  With this fix, I was wondering IAE is
>> a better exception for IDN.toASCII(".").
>>
>>>> Learn something new today to use nslookup.
>>>>
>>>>> Also, since this bug was originally about SNIHostName, do you need to
>>>>> add some extra restriction there to reject "oracle.com." things?
>>>>>
>>>> No, we cannot restrict the format of IDN in SNIHostName more than in
>>>> IDN. However, we may need to rethink about the comparing of two IDN, for
>>>> example, "example.com." should equal to "example.com".  I want to
>>>> consider it in another bug.
>>> Not sure. Does the spec say IDN and SNIHostName are equivalent sets? And
>>> it's not one is another's subset?
>>>
>> Per TLS specification, host name in SNI is an IDN.  The spec of
>> SNIHostname says, "hostname is not a valid Internationalized Domain Name
>> (IDN) compliant with the RFC 3490 specification". The spec in
>> SNIHostName has the same means as IDN.  I won't want to add additional
>> restrict beyond the specification of an IDN.
>>
>> Xuelei
>>
>>>> Can I push the changeset?
>>> I think it's better to ask someone in the networking team to make the
>>> suggestion. From what I read Michael in this thread, he does not seem
>>> totally agreed with your code changes (at least not the 00 version).
>>>
>>> Thanks
>>> Max
>>>
>>>> Thanks,
>>>> Xuelei
>>>>
>>>>> Thanks
>>>>> Max
>>>>>
>>>>> On 8/9/13 8:41 AM, Xuelei Fan wrote:
>>>>>> Ping.
>>>>>>
>>>>>> Thanks,
>>>>>> Xuelei
>>>>>>
>>>>>> On 8/7/2013 11:17 PM, Xuelei Fan wrote:
>>>>>>> Please review the new update:
>>>>>>>
>>>>>>> http://cr.openjdk.java.net./~xuelei/8020842/webrev.01/
>>>>>>>
>>>>>>> With this update, "com." is valid (return "com."); "." and
>>>>>>> "example..com" are invalid.  And IAE will be thrown for invalid IDN.
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Xuelei
>>>>>>>