Fixed race condition in global request response handling

src/main/java/net/schmizz/sshj/connection/ConnectionImpl.java

@@ -216,13 +216,15 @@ public class ConnectionImpl
             throws ConnectionException {
         synchronized (globalReqPromises) {
             Promise<SSHPacket, ConnectionException> gr = globalReqPromises.poll();
-            if (gr == null)
+            if (gr == null) {
                 throw new ConnectionException(DisconnectReason.PROTOCOL_ERROR,
-                                              "Got a global request response when none was requested");
-            else if (response == null)
+                        "Got a global request response when none was requested");
+            } else if (response == null) {
                 gr.deliverError(new ConnectionException("Global request [" + gr + "] failed"));
-            else
-                gr.deliver(response);
+            } else {
+                // To prevent a race condition, copy the packet before delivering, as it will be handled in a different thread.
+                gr.deliver(new SSHPacket(response));
+            }
         }
     }
 

src/test/resources/logback-test.xml

@@ -0,0 +1,16 @@
+<configuration>
+
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%.-20thread] %-5level %logger{36} - %msg%n</pattern>
+        </encoder>
+    </appender>
+
+    <root level="info">
+        <appender-ref ref="STDOUT"/>
+    </root>
+
+    <logger name="net.schmizz.sshj" level="debug"/>
+    <logger name="net.schmizz.sshj.transport" level="trace" />
+
+</configuration>