Close Socket to AWS KMS on exceptional path

Addresses Coverity-reported defect.

JAVA-3315

Author: jyemin

driver-sync/src/main/com/mongodb/client/internal/KeyManagementService.java

@@ -16,6 +16,7 @@
 
 package com.mongodb.client.internal;
 
+import com.mongodb.MongoSocketOpenException;
 import com.mongodb.MongoSocketWriteException;
 import com.mongodb.ServerAddress;
 
@@ -40,26 +41,52 @@ class KeyManagementService {
     }
 
     public InputStream stream(final String host, final ByteBuffer message) {
+        Socket socket;
+        try {
+            socket = sslContext.getSocketFactory().createSocket();
+        } catch (IOException e) {
+            throw new MongoSocketOpenException("Exception opening connection to Key Management Service", new ServerAddress(host, port), e);
+        }
+
         try {
-            Socket socket = sslContext.getSocketFactory().createSocket();
             socket.setSoTimeout(timeoutMillis);
             socket.connect(new InetSocketAddress(InetAddress.getByName(host), port), timeoutMillis);
+        } catch (IOException e) {
+            closeSocket(socket);
+            throw new MongoSocketOpenException("Exception opening connection to Key Management Service", new ServerAddress(host, port), e);
+        }
 
+        try {
             OutputStream outputStream = socket.getOutputStream();
 
             byte[] bytes = new byte[message.remaining()];
 
             message.get(bytes);
             outputStream.write(bytes);
+        } catch (IOException e) {
+            closeSocket(socket);
+            throw new MongoSocketWriteException("Exception sending message to Key Management Service",
+                    new ServerAddress(host, port), e);
+        }
 
+        try {
             return socket.getInputStream();
-
         } catch (IOException e) {
-            throw new MongoSocketWriteException("Exception sending message to Key Management Service", new ServerAddress(host, port), e);
+            closeSocket(socket);
+            throw new MongoSocketWriteException("Exception receiving message from Key Management Service",
+                    new ServerAddress(host, port), e);
         }
     }
 
     public int getPort() {
         return port;
     }
+
+    private void closeSocket(final Socket socket) {
+        try {
+            socket.close();
+        } catch (IOException e) {
+            // ignore
+        }
+    }
 }