Disabling client SSL session caching breaks SNI

[elipsion]

Jetty version(s)
11.0.7

Java version/vendor
AdoptOpenJDK 11.0.11.9-hotspot

OS type/version
Windows 11 21H2

Description
Disabling session caching in SslContextFactory has the unexpected side-effect of also disabling SNI.
It affects a decision when creating an SSLEngine which seeps down into the innards of Java SSL implementations

How to reproduce?
Create two Jetty HttpClients, one having a SslContextFactory with Session Caching disabled.
Run java with -Djavax.net.debug=all and look for this error

[github-actions]

This issue has been automatically marked as stale because it has been a
full year without activity. It will be closed if no further activity occurs.
Thank you for your contributions.

[elipsion]

Uh, bump?

[github-actions]

This issue has been automatically marked as stale because it has been a
full year without activity. It will be closed if no further activity occurs.
Thank you for your contributions.

[sbordet]

@elipsion sorry for the delay looking into this.

Disabling session caching via SslContextFactory does not have any effect on the underlying SSLContext, it is just really to pick whether to call SSLContext.createSSLEngine() or SSLContext.createSSLEngine(String, int).
It does not have any effect on the actual SSLContext session cache.

So if your goal is to disable SSLSession caching, calling SslContextFactory.setSessionCachingEnabled(false) is the wrong method.

However, note that disabling SSLSession caching is not possible, see #519.

Your only option is to invalidate the SSLSession on the server-side, each time, for example using a Connection.Listener (see https://eclipse.dev/jetty/documentation/jetty-12/programming-guide/index.html#pg-arch-io-connection-listener).

[sbordet]

I'm closing this as it works as expected.
Please comment if you have further insights.