Permissions and OS Security Alice and Bob are taking one CS courses. Carl is the TA and David is the instructor. You are asked to maintain user groups and assign proper permissions to individual folders on the Linux server they use. For the folder slides, David and Carl update files (e. g., lec1.pdf, lec2.pdf) and the files are open to all students. For the folder project, Alice and Bob can only upload their own file (e. g, Alice. tar. gz, Bob. tar. gz) but not download any files here. In the meantime, they are allowed to list the files in this folder to confirm if they have submitted or not as well as the timestamp, but they are not allowed to write or create files in this folder. Thus, they will use the provided turnin program to submit. Please lit the proper user groups and users in the group, permissions for each folder and the logic for the turnin program.