these probably need to be dup'd

lib/secure_headers/headers/content_security_policy_config.rb

@@ -10,30 +10,30 @@ module SecureHeaders
         new_instance = new
         new_instance.base_uri = instance.base_uri
         new_instance.block_all_mixed_content = instance.block_all_mixed_content
-        new_instance.child_src = instance.child_src
-        new_instance.connect_src = instance.connect_src
-        new_instance.default_src = instance.default_src
-        new_instance.font_src = instance.font_src
-        new_instance.form_action = instance.form_action
-        new_instance.frame_ancestors = instance.frame_ancestors
-        new_instance.frame_src = instance.frame_src
-        new_instance.img_src = instance.img_src
-        new_instance.manifest_src = instance.manifest_src
-        new_instance.media_src = instance.media_src
-        new_instance.navigate_to = instance.navigate_to
-        new_instance.object_src = instance.object_src
+        new_instance.child_src = instance.child_src.dup
+        new_instance.connect_src = instance.connect_src.dup
+        new_instance.default_src = instance.default_src.dup
+        new_instance.font_src = instance.font_src.dup
+        new_instance.form_action = instance.form_action.dup
+        new_instance.frame_ancestors = instance.frame_ancestors.dup
+        new_instance.frame_src = instance.frame_src.dup
+        new_instance.img_src = instance.img_src.dup
+        new_instance.manifest_src = instance.manifest_src.dup
+        new_instance.media_src = instance.media_src.dup
+        new_instance.navigate_to = instance.navigate_to.dup
+        new_instance.object_src = instance.object_src.dup
         new_instance.plugin_types = instance.plugin_types
-        new_instance.prefetch_src = instance.prefetch_src
+        new_instance.prefetch_src = instance.prefetch_src.dup
         new_instance.preserve_schemes = instance.preserve_schemes
         new_instance.report_only = instance.report_only
-        new_instance.report_uri = instance.report_uri
+        new_instance.report_uri = instance.report_uri.dup
         new_instance.require_sri_for = instance.require_sri_for
         new_instance.sandbox = instance.sandbox
         new_instance.script_nonce = instance.script_nonce
-        new_instance.script_src = instance.script_src
+        new_instance.script_src = instance.script_src.dup
         new_instance.style_nonce = instance.style_nonce
-        new_instance.style_src = instance.style_src
-        new_instance.worker_src = instance.worker_src
+        new_instance.style_src = instance.style_src.dup
+        new_instance.worker_src = instance.worker_src.dup
         new_instance.upgrade_insecure_requests = instance.upgrade_insecure_requests
         new_instance.disable_nonce_backwards_compatibility = instance.disable_nonce_backwards_compatibility
         new_instance.disable_minification = instance.disable_minification