1)	In what environments is mandatory access control useful?

2)	Consider the following set of Unix permissions:

	/                       rwx,r-x,r-x     root    root
	/home                   rwx,r-x,r-x     root    root
	/home/smb               rwx,r-x,--x     smb     faculty
	/home/smb/upload        rwx,-wx,-wx     smb     faculty
	/home/smb/upload/td     rw-,---,---     smb     faculty
	/home/smb/upload/xy     rw-,r--,r--     robin   student
	/home/chris             rwx,--x,--x     chris   other
	/home/chris/proj        r-x,rwx,---     chris   proj

	Below is a list of commands, preceded by the user.group of
	the process.  Which commands will succeed?

	For command (c), assume that the two directories are on
	the same file system.

	For command (e), assume that the processs current working
	directory is /home/smb/upload.  For commands that fail,
	explain which permission entry caused the failure.

	(a) chris.root    date >/home/chris/proj/now
	(b) pat.student   echo data >/home/smb/upload/p1
	(c) chris.other   mv /home/smb/upload/td /home/chris
	(d) joe.student   ls -l /home/smb/upload/xy
	(e) sue.faculty   cd ../../chris


3)      There is a network file transfer daemon that maintains a
	queue of pending and past requests.  It uses three directories,
	with the following ownership and permission:

	pending   trans:daemon   rwx,rx,x
	done      trans:daemon   rwx,rx,x
	data      trans:daemon   rwx,-,-

	The control files are in 'pending' or 'done', depending on the
	request status.  The data files being transferred are, of course,
	in the 'data' directory.

	a) The program that actually transfers files has to be able
	to read the control file directory, read individual control
	files, read the associated data files, and move the control
	files to the done directory. What privileges must this
	program run with?

	b) The program that gives the queue status needs to be able
	to read the control file directory and individual control
	files. It does not need to read data files. What privileges
	must this program run with?

	c) Why is it a good idea for the queue status program to
	have fewer privileges than the transfer program?