RFR: 8331682: Slow networks/Impatient clients can potentially send unencrypted TLSv1.3 alerts that won't parse on the server [v25]

[Artur Barashev]

> Check for unexpected plaintext alert message during TLSv1.3 handshake. This can happen if client doesn't receive ServerHello due to network timeout and tries to close the connection by sending an alert message.

Artur Barashev has updated the pull request incrementally with one additional commit since the last revision:

  - Print alert level
  - Check for the number of bytes remaining in the buffer
  - Adjust line length to be <= 80 characters

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Changes:
  - all: https://git.openjdk.org/jdk/pull/21043/files
  - new: https://git.openjdk.org/jdk/pull/21043/files/aef08dd0..9eb2fe0d

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21043&range=24
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21043&range=23-24

  Stats: 44 lines in 4 files changed: 17 ins; 0 del; 27 mod
  Patch: https://git.openjdk.org/jdk/pull/21043.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21043/head:pull/21043

PR: https://git.openjdk.org/jdk/pull/21043