A New Problem

Michele in the Marketing department would also like to use the summary program to find out who’s buying the product. Steve does this: 

   chmod og+rx summarize

Now his permissions look like this: 

-rw-------  steve  sales  customers.dat
-rwxr-xr-x  steve  sales  summarize

Now everyone can execute the summary program, but the customer file is still protected, Steve thinks. Well, unfortunately, it is. Let’s see what happens when Michele tries to run the program.

EventLinux says
Michele types /home/steve/summarize You are user michele of group mktg.
You are “other”.
You want to execute file /home/steve/summarize.
Permission granted.
Program begins. ---
Program asks to read file /home/steve/customers.dat You are user michele of group mktg.
You are “other”.
You want to read file /home/steve/customers.dat.
Permission denied.

Steve has a problem. If he says: 

   chmod og+r customers.dat

then the customer file is open to anyone at any time. If only Steve could say, “Give Michele the same permissions that I have–but only if she’s running my program.”

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