Add whitelist entry for SSLEngineImpl.wrap to BlockHound configuration (#10844)

Motivation:

Internally SSLEngineImpl.wrap(...) may call FileInputStream.read(...).
This will cause the error below when BlockHound is enabled
reactor.blockhound.BlockingOperationError: Blocking call! java.io.FileInputStream#readBytes
	at java.io.FileInputStream.readBytes(FileInputStream.java)
	at java.io.FileInputStream.read(FileInputStream.java:255)

Modifications:

- Add whitelist entry to BlockHound configuration
- Add test

Result:

Fixes #10837

common/src/main/java/io/netty/util/internal/Hidden.java

@@ -111,6 +111,10 @@ class Hidden {
                     "sun.security.ssl.SSLEngineImpl",
                     "unwrap");
 
+            builder.allowBlockingCallsInside(
+                    "sun.security.ssl.SSLEngineImpl",
+                    "wrap");
+
             builder.nonBlockingThreadPredicate(new Function<Predicate<Thread>, Predicate<Thread>>() {
                 @Override
                 public Predicate<Thread> apply(final Predicate<Thread> p) {

transport-blockhound-tests/src/test/java/io/netty/util/internal/NettyBlockHoundIntegrationTest.java

@@ -20,6 +20,7 @@ import io.netty.bootstrap.ServerBootstrap;
 import io.netty.buffer.UnpooledByteBufAllocator;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelFuture;
+import io.netty.channel.ChannelFutureListener;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInboundHandlerAdapter;
 import io.netty.channel.ChannelInitializer;
@@ -63,9 +64,13 @@ import java.util.concurrent.Future;
 import java.util.concurrent.FutureTask;
 import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
 import java.util.concurrent.locks.ReentrantLock;
 
+import static io.netty.buffer.Unpooled.wrappedBuffer;
 import static org.hamcrest.MatcherAssert.assertThat;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 import static org.junit.Assume.assumeTrue;
 
@@ -238,6 +243,77 @@ public class NettyBlockHoundIntegrationTest {
         testTrustManagerVerify("TLSv1.3");
     }
 
+    @Test
+    public void testSslHandlerWrapAllowsBlockingCalls() throws Exception {
+        final SslContext sslClientCtx =
+                SslContextBuilder.forClient()
+                                 .trustManager(InsecureTrustManagerFactory.INSTANCE)
+                                 .sslProvider(SslProvider.JDK)
+                                 .build();
+        final SslHandler sslHandler = sslClientCtx.newHandler(UnpooledByteBufAllocator.DEFAULT);
+        final EventLoopGroup group = new NioEventLoopGroup();
+        final CountDownLatch activeLatch = new CountDownLatch(1);
+        final AtomicReference<Throwable> error = new AtomicReference<>();
+
+        Channel sc = null;
+        Channel cc = null;
+        try {
+            sc = new ServerBootstrap()
+                    .group(group)
+                    .channel(NioServerSocketChannel.class)
+                    .childHandler(new ChannelInboundHandlerAdapter())
+                    .bind(new InetSocketAddress(0))
+                    .syncUninterruptibly()
+                    .channel();
+
+            cc = new Bootstrap()
+                    .group(group)
+                    .channel(NioSocketChannel.class)
+                    .handler(new ChannelInitializer<Channel>() {
+
+                        @Override
+                        protected void initChannel(Channel ch) {
+                            ch.pipeline().addLast(sslHandler);
+                            ch.pipeline().addLast(new ChannelInboundHandlerAdapter() {
+
+                                @Override
+                                public void channelActive(ChannelHandlerContext ctx) {
+                                    activeLatch.countDown();
+                                }
+
+                                @Override
+                                public void userEventTriggered(ChannelHandlerContext ctx, Object evt) {
+                                    if (evt instanceof SslHandshakeCompletionEvent &&
+                                            ((SslHandshakeCompletionEvent) evt).cause() != null) {
+                                        Throwable cause = ((SslHandshakeCompletionEvent) evt).cause();
+                                        cause.printStackTrace();
+                                        error.set(cause);
+                                    }
+                                    ctx.fireUserEventTriggered(evt);
+                                }
+                            });
+                        }
+                    })
+                    .connect(sc.localAddress())
+                    .addListener((ChannelFutureListener) future ->
+                        future.channel().writeAndFlush(wrappedBuffer(new byte [] { 1, 2, 3, 4 })))
+                    .syncUninterruptibly()
+                    .channel();
+
+            assertTrue(activeLatch.await(5, TimeUnit.SECONDS));
+            assertNull(error.get());
+        } finally {
+            if (cc != null) {
+                cc.close().syncUninterruptibly();
+            }
+            if (sc != null) {
+                sc.close().syncUninterruptibly();
+            }
+            group.shutdownGracefully();
+            ReferenceCountUtil.release(sslClientCtx);
+        }
+    }
+
     private static void testTrustManagerVerify(String tlsVersion) throws Exception {
         final SslContext sslClientCtx =
                 SslContextBuilder.forClient()