Ping.

--J

-------- Forwarded Message --------
Subject:        RFR JDK-8247630: Use two key share entries
Date:   Wed, 8 Jul 2020 15:57:15 -0700
From:   Jamil Nimeh <jamil.j.ni...@oracle.com>
To:     security-dev@openjdk.java.net



Hello all,

This is a small enhancement to the TLS 1.3 client hello.  With this change JSSE will make a best-effort attempt to select the most-preferred XDH and ECDHE named group.  In most cases this will be x25519 and secp256r1.  This was done to help reduce the number of times our clients get HelloRetryRequests due to servers wanting secp256r1 when we would just assert x25519.

The asserted key shares can be affected by different settings for the jdk.tls.namedGroups System property.  If x25519 and/or secp256r1 are missing, the next-most-preferred named group of that class will be selected.  If no other named group in that class is in the supported_groups extension, then it will be skipped.  In the unlikely event that no XDH or ECDHE supported group is asserted, then the client will assert one key share, the most preferred one out of the supported groups.

This also fixes one minor spec compliance issue where we weren't throwing an exception when a server returned an illegal HelloRetryRequest with a named group that was in the original key_shares extension from the client hello.

Webrev: https://cr.openjdk.java.net/~jnimeh/reviews/8247630/webrev.01/

JBS: https://bugs.openjdk.java.net/browse/JDK-8247630

--Jamil

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