Unix Process Ownership and Permissions - Quiz Explanation
The correct answers are indicated below, along with text that explains the correct answers.
1.
The effective user ID of a process is
Please select the best answer.
A.
The ID of the user who started that process
B.
The user ID of the init process
C.
The ID of the user who booted the system
D.
The user ID used to evaluate access permissions for that process
The correct answer is D.
The real user or group ID of a process is the ID of the user or group who started that process. The effective user or group ID is the user or group ID that the system uses to evaluate access permissions for that process.
2.
What is the ancestor of all processes on the system?
Please select the best answer.
A.
grep
B.
su
C.
init
D.
chmod
The correct answer is C.
The
grep
command searches the named input files for lines containing a match to the given pattern. The
su
command, without any arguments, asserts root privileges. The
chmod
command allows you to change the access mode of a file.
3.
For what are the SUID and SGID bits used?
Please select the best answer.
A.
To change a file’s ownership and permissions when it is executed
B.
To change a file’s group permissions
C.
To allow a program to run with additional permissions
D.
To allow running processes to change file user IDs to root
The correct answer is C.
Do not forget, however, that allowing a user to acquire more permissions temporarily means the user may be a source of security problems.
