JSSE: check if inRemaining == 0

[rlm2002]

Adds a check for inRemaining == 0 when detecting if status needs to be set to BUFFER_UNDERFLOW. inRemaining is the input buffer size at unwrap entry, while in.remaining() is after processing. Requiring both to be 0 limits this path to the “no bytes were supplied this call” case. Avoids “all supplied bytes were consumed but more ciphertext is still needed” case being handled the same way.

Adds regression test testHandshakeUnwrapConsumedNotBufferUnderflow().

Fixes SunJSSE ServerName tests: ServerName/SSLEngineExplorerMatchedSNI.java, ServerName/SSLEngineExplorerWithCli.java, ServerName/SSLEngineExplorerWithSrv.java

[Copilot]

Pull request overview

This PR refines wolfJSSE SSLEngine.unwrap() status mapping to avoid returning BUFFER_UNDERFLOW when the caller did provide input bytes (but those bytes were consumed and native wolfSSL still needs more ciphertext). It also adds a regression test covering this specific “consumed input but still WANT_READ” handshake scenario in TLS 1.3.

Changes:

• Tighten the BUFFER_UNDERFLOW detection condition by additionally requiring inRemaining == 0 (no bytes supplied at unwrap entry).
• Add a TLS 1.3 regression test ensuring unwrap() does not return BUFFER_UNDERFLOW when it consumed non-empty handshake input.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/java/com/wolfssl/provider/jsse/WolfSSLEngine.java	Adds inRemaining == 0 guard to restrict BUFFER_UNDERFLOW to the “no input provided” case.
src/test/com/wolfssl/provider/jsse/test/WolfSSLEngineTest.java	Adds regression test testHandshakeUnwrapConsumedNotBufferUnderflow() for the adjusted unwrap-status behavior in TLS 1.3.

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