Homework: Microkernels and capabilities

Read: KeyKOS paper and Confused deputy.

Hand-In Procedure

You are to turn in this homework during lecture. Please write up your answers to the exercises below and hand them in to a 6.828 staff member at the beginning of lecture.

1. Give an example of how an application running on top of the KeyKOS UNIX port (KeyNIX) can still suffer from the confused deputy problem.
2. Would we need to modify the application, the UNIX keeper, or the KeyKOS kernel to avoid the confused deputy problem in a program running on KeyNIX?
3. Is it possible to avoid the confused deputy problem on a traditional Unix system? Provide a brief explanation for why or why not.