RFR [13] JDK-8225766 : Curve in certificate should not affect signature scheme when using TLSv1.3

[Xuelei Fan]

Hi,

Could I get the following update reviewed?

    http://cr.openjdk.java.net/~xuelei/8225766/webrev.01/

For TLS 1.2 and prior versions, the public key of a EC cert MUST use a 
curve and point format supported by the client. But in TLS 1.3, 
signature algorithms are negotiated independently via the 
"signature_algorithms" extension.  The JDK implementation does not 
comply to this behavior changes in TLS 1.3.

There is a corner case that the signature algorithm "ecdsa_sha1" does 
not define the related curves.  If the key uses an unsupported curves, 
the peer cannot verify the signature.  In this fix, a countermeasure is 
introduced to mitigate the impact by checking that the curve used for 
"ecdsa_sha1" is local supported.

Please read the code for more details.

Thanks,
Xuelei