NIFI-7913 Set Enabled TLS Protocols on ListenSMTP

[exceptionfactory]

Description of PR

NIFI-7913 Adds getEnabledProtocols to TlsConfiguration and updates ListenSMTP to call SSLSocket.setEnabledProtocols() when configured with SSL Context Service. The getEnabledProtocols() implementation in StandardTlsConfiguration supports the generic values of SSL and TLS as well as specified TLS protocol versions. The getEnabledProtocols() implementation returns legacy TLS 1.0 and TLS 1.1 only when the configured protocol property is set to SSL. Otherwise the implementation returns either the specific protocol version configured, or the secure supported protocol versions based on the running JVM version. ListenSMTP unit tests updated to include expected exceptions for misaligned TLS protocol version.

Based on this implementation, ListenSMTP configured with StandardRestrictedSSLContextService will work as follows:

Java 8

• TLS Protocol set to TLS enables TLSv1.2

Java 11

• TLS Protocol set to TLS enables TLSv1.2 and TLSv1.3

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[thenatog]

Will review

[thenatog]

Spent a while testing this out. I found that your change appears to work - it will follow the context service's setting for the protocol restriction (setting 1.3 only, or setting TLS allowed 1.2 and 1.3).

I found a small security issue I will disclose separately.