GEODE-6664 CI failure: org.apache.geode.ClusterCommunicationsDUnitTest.receiveBigResponse

Ensure that the encrypted buffer is at least as big as the
SSLSession's packet buffer size.  That's required for proper decryption
of incoming packets.

(cherry picked from commit ff703dd)

Author: bschuchardt

geode-core/src/main/java/org/apache/geode/internal/net/NioSslEngine.java

@@ -308,18 +308,17 @@ void expandPeerAppData(ByteBuffer wrappedBuffer) {
     }
   }
 
-  /*
-   * NioSslEngine doesn't need to ensure capacity in network buffers because they
-   * are fixed in size by the SslContext. The size recommended by the context is
-   * big enough for the SslEngine to do its work.
-   */
   @Override
   public ByteBuffer ensureWrappedCapacity(int amount, ByteBuffer wrappedBuffer,
       Buffers.BufferType bufferType, DMStats stats) {
-    if (wrappedBuffer == null) {
-      wrappedBuffer = Buffers.acquireBuffer(bufferType, amount, stats);
+    ByteBuffer buffer = wrappedBuffer;
+    int requiredSize = engine.getSession().getPacketBufferSize();
+    if (buffer == null) {
+      buffer = Buffers.acquireBuffer(bufferType, requiredSize, stats);
+    } else if (buffer.capacity() < requiredSize) {
+      buffer = Buffers.expandWriteBufferIfNeeded(bufferType, buffer, requiredSize, stats);
     }
-    return wrappedBuffer;
+    return buffer;
   }
 
   @Override

geode-core/src/test/java/org/apache/geode/internal/net/NioSslEngineTest.java

@@ -373,13 +373,21 @@ public void closeWhenSocketWriteError() throws Exception {
   }
 
   @Test
-  public void ensureWrappedCapacity() {
-    ByteBuffer buffer = ByteBuffer.allocate(10);
+  public void ensureWrappedCapacityOfSmallMessage() {
+    ByteBuffer buffer = ByteBuffer.allocate(netBufferSize);
     assertThat(
         nioSslEngine.ensureWrappedCapacity(10, buffer, Buffers.BufferType.UNTRACKED, mockStats))
             .isEqualTo(buffer);
   }
 
+  @Test
+  public void ensureWrappedCapacityWithNoBuffer() {
+    assertThat(
+        nioSslEngine.ensureWrappedCapacity(10, null, Buffers.BufferType.UNTRACKED, mockStats)
+            .capacity())
+                .isEqualTo(netBufferSize);
+  }
+
   @Test
   public void readAtLeast() throws Exception {
     final int amountToRead = 150;