Code Review Request, 8133070 Hot lock on BulkCipher.isAvailable

Sean Mullan sean.mullan at oracle.com
Fri Dec 18 15:35:04 UTC 2015


Here are a few other other comments on the code:

SSLContextImpl:
   - I noticed that SSLContext.init does not specify how it handles 
empty arrays, and you have changed the code so that an empty 
TrustManager array is treated like they are null - is this change in 
behavior a compatibility issue at all? Could you file a follow-on issue 
to clarify the behavior of SSLContext.init as to how it should handle 
empty arrays?

   - are there any race conditions that you need to worry about now that 
you have removed the synchronized blocks from 
getSupportedCipherSuiteList and getDefaultCipherSuite?

   - on lines 781 and 789, an empty array is created and discarded if 
there is not an exception thrown. It would be better to only create the 
empty array when an exception is thrown (move it into the catch block).

--Sean


On 12/14/2015 10:08 PM, Xuelei Fan wrote:
> On 12/15/2015 4:24 AM, Sean Mullan wrote:
>> Hi Xuelei,
>>
>> For JDK 9, the EC impl is defined to be in its own module
>> (jdk.crypto.ec). How does it affect this fix if that module is not
>> available/installed?
>>
> The SunJSSE provider would not support dynamically loading of crypto
> providers/modules.  At present, there are two providers that supports EC
> implementation, SunEC (jdk.crypto.ec) and SunPKCS11 (jdk.crypto.pkcs11).
>   If no EC provider, EC cipher suites would not be available to use.
> That's to say, EC cipher suites would not be enabled by default, and
> cannot be used for handshaking.  In the fix,
> JsseJce#EcAvailability.isAvailable is used to check the availability of
> EC crypto impl.
>
> Xuelei
>
>> --Sean
>>
>> On 12/01/2015 07:49 AM, Xuelei Fan wrote:
>>> Hi,
>>>
>>> Please review the fix for JDK-8133070:
>>>
>>>      http://cr.openjdk.java.net/~xuelei/8133070/webrev.00/
>>>
>>> In (Open)JDK 6, EC cipher suites get supported by Java.  However, there
>>> is no default EC provider in JDK 6 at that time.  In order to support
>>> third part's EC algorithm JCE provider dynamically, it is hard-coded to
>>> check the cipher suite availability dynamically for EC algorithms in
>>> SunJSSE provider.
>>>
>>> Here is an example update in CipherSuite.java for the checking:
>>>
>>>     -   static final boolean DYNAMIC_AVAILABILITY = false;
>>>     +   static final boolean DYNAMIC_AVAILABILITY = true;
>>>
>>> The dynamically checking impacts the performance significantly as:
>>> 1. the check of the availability is expensive as it involves crypto
>>> operations.
>>> 2. a cache is used to maintain the availability of bulk ciphers in order
>>> to mitigate the #1 performance impact.  However, access and update to
>>> the cache need to be synchronized.
>>> 3. in order to support dynamically checking, the cache may be cleared if
>>> a particular cipher is not found or a new SSLContext is generated. As
>>> bring the performance impact of #1 back again.
>>>
>>> Later, AEAD algorithm is defined by Java.  The same mechanism is used to
>>> support AEAD ciphers.
>>>
>>> Now, EC and GCM algorithms are supported in JDK crypto providers. The
>>> hard-coded checking can get improved.  This fix updates:
>>> 1. remove the dynamically checking of cipher suite availability.
>>> 2. remove the cipher suite availability cache accordingly (need no
>>> synchronization accordingly)
>>> 3. other updates that impact by the availability checking.
>>>
>>> The performance improvement is tested with the following simple case.
>>> Run the following code 1000, 2000, 3000 times in single thread mode and
>>> measure the millisecond for each:
>>>
>>> ---------
>>> String[] cipherSuites =
>>>           {"TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256"};
>>> for (int i = 0; i < loops; i++) {  // loops: 1000, 2000, 3000
>>>       SSLEngine engine = SSLContext.getDefault().createSSLEngine();
>>>       engine.getEnabledCipherSuites();
>>>       engine.getSupportedCipherSuites();
>>> }
>>> ---------
>>>
>>> The milliseconds for each test case (less is better) look like:
>>>
>>>       loops   |  old    |  fixed
>>>      ---------+---------+----------
>>>      1000     |  2736   |  735
>>>      ---------+---------+----------
>>>      2000     |  3718   |  746
>>>      ---------+---------+----------
>>>      3000     |  4750   |  765
>>>      ---------+---------+----------
>>>
>>> This fix improves the performance.
>>>
>>> The existing regression testing get passed.  No new regression test is
>>> planned as this is a performance enhancement fix.
>>>
>>> Thanks,
>>> Xuelei
>>>
>


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