Fix a bug in SslHandler where a ClassCastException is raised when non-ByteBuf message is passed

- Fixes #1828

handler/src/main/java/io/netty/handler/ssl/SslHandler.java

@@ -437,6 +437,12 @@ public class SslHandler extends ByteToMessageDecoder {
                     out = ctx.alloc().buffer(maxPacketBufferSize);
                 }
 
+                if (!(pending.msg() instanceof ByteBuf)) {
+                    ctx.write(pending.msg(), (ChannelPromise) pending.recycleAndGet());
+                    pendingUnencryptedWrites.remove();
+                    continue;
+                }
+
                 ByteBuf buf = (ByteBuf) pending.msg();
                 SSLEngineResult result = wrap(engine, buf, out);
 

handler/src/test/java/io/netty/handler/ssl/SslHandlerTest.java

@@ -52,4 +52,22 @@ public class SslHandlerTest {
             assertThat(e.getCause(), is(instanceOf(SSLProtocolException.class)));
         }
     }
+
+    @Test
+    public void testNonByteBufPassthrough() throws Exception {
+        SSLEngine engine = SSLContext.getDefault().createSSLEngine();
+        engine.setUseClientMode(false);
+
+        EmbeddedChannel ch = new EmbeddedChannel(new SslHandler(engine));
+
+        Object msg1 = new Object();
+        ch.writeOutbound(msg1);
+        assertThat(ch.readOutbound(), is(sameInstance(msg1)));
+
+        Object msg2 = new Object();
+        ch.writeInbound(msg2);
+        assertThat(ch.readInbound(), is(sameInstance(msg2)));
+
+        ch.finish();
+    }
 }