update _display_value to handle None case

Author: eve-mem

volatility3/cli/volshell/generic.py

@@ -587,26 +587,43 @@ def _display_simple_type(
 
     def _display_value(self, value: Any) -> str:
         try:
+            # if value is a BaseAbsentValue they display N/A
             if isinstance(value, interfaces.renderers.BaseAbsentValue):
                 return "N/A"
-            elif isinstance(value, objects.Pointer):
-                # show pointers in hex to match output for struct addrs
-                # highlight null or unreadable pointers
-                if value == 0:
-                    suffix = " (null pointer)"
-                elif not value.is_readable():
-                    suffix = " (unreadable pointer)"
-                else:
-                    suffix = ""
-                return f"{hex(value)}{suffix}"
-            elif isinstance(value, objects.PrimitiveObject):
-                return repr(value)
-            elif isinstance(value, objects.Array):
-                return repr([self._display_value(val) for val in value])
             else:
-                return hex(value.vol.offset)
+                # volobject branch
+                if isinstance(
+                    value,
+                    Union[
+                        interfaces.objects.ObjectInterface, interfaces.objects.Template
+                    ],
+                ):
+                    if isinstance(value, objects.Pointer):
+                        # show pointers in hex to match output for struct addrs
+                        # highlight null or unreadable pointers
+                        if value == 0:
+                            suffix = " (null pointer)"
+                        elif not value.is_readable():
+                            suffix = " (unreadable pointer)"
+                        else:
+                            suffix = ""
+                        return f"{hex(value)}{suffix}"
+                    elif isinstance(value, objects.PrimitiveObject):
+                        return repr(value)
+                    elif isinstance(value, objects.Array):
+                        return repr([self._display_value(val) for val in value])
+                    else:
+                        return hex(value.vol.offset)
+                else:
+                    # non volobject
+                    if value is None:
+                        return "N/A"
+                    else:
+                        return value
+
         except exceptions.InvalidAddressException:
-            return "-"
+            # if value causes an InvalidAddressException like BaseAbsentValue then display N/A
+            return "N/A"
 
     def generate_treegrid(
         self, plugin: Type[interfaces.plugins.PluginInterface], **kwargs