diff --git a/builder/docker/step_connect_docker.go b/builder/docker/step_connect_docker.go
index da2be51af..315cfc204 100644
--- a/builder/docker/step_connect_docker.go
+++ b/builder/docker/step_connect_docker.go
@@ -7,7 +7,7 @@ import (
 type StepConnectDocker struct{}
 
 func (s *StepConnectDocker) Run(state multistep.StateBag) multistep.StepAction {
-	config := state.Get("config").(Config)
+	config := state.Get("config").(*Config)
 	containerId := state.Get("container_id").(string)
 	driver := state.Get("driver").(Driver)
 	tempDir := state.Get("temp_dir").(string)