WriteTimeoutSocket::getFileDescriptor$ support for Conscrypt #505 (#507)

WriteTimeoutSocket::getFileDescriptor$ support for Conscrypt #505

doc/release/CHANGES.txt

@@ -29,6 +29,7 @@ E  456	MimeMessage.setFrom(null) fails instead of removing the header
 E  461	OAuth2 POP3 Support for Microsoft
 E  473	Several modules are not included in build when JDK11 is used
 E  493	javamail.providers file missing from provider jars after 1.6.5
+E  505	WriteTimeoutSocket::getFileDescriptor$ support for Conscrypt
 
 
 		  CHANGES IN THE 2.0.0 RELEASE

mail/src/main/java/com/sun/mail/util/WriteTimeoutSocket.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013, 2019 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2013, 2021 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0, which is available at
@@ -322,12 +322,20 @@ public Set<SocketOption<?>> supportedOptions() {
      * @return	the FileDescriptor object
      */
     public FileDescriptor getFileDescriptor$() {
-	try {
-	    Method m = Socket.class.getDeclaredMethod("getFileDescriptor$");
-	    return (FileDescriptor)m.invoke(socket);
-	} catch (Exception ex) {
-	    return null;
-	}
+    	//The loop handles issues with non-public classes between 
+    	//java.net.Socket and the actual socket type held in this object.
+    	//Must inspect java.net.Socket to ensure compatiblity with old behavior.
+    	for (Class<?> k = socket.getClass(); k != Object.class; k = k.getSuperclass()) {
+            try {
+                Method m = k.getDeclaredMethod("getFileDescriptor$");  
+                if (FileDescriptor.class.isAssignableFrom(m.getReturnType())) {
+                        //Skip setAccessible so non-public methods fail to invoke.
+                    return (FileDescriptor) m.invoke(socket);
+                }
+            } catch (Exception ignore) {
+            }
+        }
+        return null;
     }
 }
 

mail/src/test/java/com/sun/mail/util/WriteTimeoutSocketTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2009, 2020 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2009, 2021 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0, which is available at
@@ -18,8 +18,10 @@
 
 import java.lang.reflect.*;
 
+import java.io.FileDescriptor;
 import java.io.IOException;
 import java.io.InterruptedIOException;
+import java.net.Socket;
 import java.util.Properties;
 import java.util.List;
 import java.util.ArrayList;
@@ -42,6 +44,7 @@
 import org.junit.rules.Timeout;
 import static org.junit.Assert.fail;
 import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.assertNotNull;
 
 /**
  * Test that write timeouts work.
@@ -205,6 +208,41 @@ else if (j == 63)
             }
         }
     }
+
+    @Test
+    public void testFileDescriptor$() throws Exception {
+    	try (PublicFileSocket ps = new PublicFileSocket()) {
+            assertNotNull(ps.getFileDescriptor$());
+    	}
+
+    	testFileDescriptor$(new PublicFileSocket());
+    	testFileDescriptor$(new PublicFileSocket1of3());
+    	testFileDescriptor$(new PublicFileSocket2of3());
+    	testFileDescriptor$(new PublicFileSocket3of3());
+    }
+
+    private void testFileDescriptor$(Socket s) throws Exception {
+    	try (WriteTimeoutSocket ws = new WriteTimeoutSocket(s, 1000)) {
+            assertNotNull(ws.getFileDescriptor$());
+    	} finally {
+            s.close();
+    	}
+    }
+
+    private static class PublicFileSocket extends Socket {
+    	public FileDescriptor getFileDescriptor$() {
+            return new FileDescriptor();
+    	}
+    }
+
+    private static class PublicFileSocket1of3 extends PublicFileSocket {
+    }
+
+    private static class PublicFileSocket2of3 extends PublicFileSocket1of3 {
+    }
+
+    private static class PublicFileSocket3of3 extends PublicFileSocket2of3 {
+    }
 
     /**
      * Custom handler.