Code Review Request JDK-8209965 : The "supported_groups" extension in ServerHellos

[Xuelei Fan]

Hi,

Please review a compatibility fix for SunJSSE provider:
     http://cr.openjdk.java.net/~xuelei/8209965/webrev.00

There are servers that send the supported_groups extension in the 
ServerHello handshake message.  It does not comply to the specification. 
  However, as there are a few deployments already with the buggy 
implementation, we may want to tolerate this behavior in JDK.

Note that although this extension is allowed in the ServerHello, it 
should be ignored and have no impact on the client behavior.

The problem was reported and the fix was tested in OopenJDK:
http://mail.openjdk.java.net/pipermail/security-dev/2018-August/018005.html


Thanks,
Xuelei