Trouble with setting permissions and such

ETC Homework & Coursework Questions
1

I have been trying so hard to be able to do this on my own but I feel I am not grasping what is being asked and I don't know how to start. I Am learning sysadmin fundementals but it is extremely hard. Please help!

  1. The problem statement, all variables and given/known data:
    Set permissions on sensitive files:

Set permissions on /etc/shadow to allow only root read and write access.
Set permissions on /etc/gshadow to allow only root read and write access.
Set permissions on /etc/group to allow root read and write access, and allow everyone else read access only.
Set permissions on /etc/passwd to allow root read and write access, and allow everyone else read access only.

Create user accounts:

Add user accounts adam, billy, sally, max, tripwire and sysadmin.
Force users to create 16 character passwords incorporating numbers and symbols.
Force passwords to expire every 90 days.
Ensure that only the admin has general sudo access.

  1. Relevant commands, code, scripts, algorithms:
    chmod, chown, chage, groups, usermod, etc

  2. The attempts at a solution (include all code and scripts):

chmod +rwx /etc/shadow
chmod /etc/shadow
ls -l /etc/shadow
chown -c /etc/shadow
  1. Complete Name of School (University), City (State), Country, Name of Professor, and Course Number (Link to Course):
    University of Riverside, California, Matthew Summerville, Cybersecuirty Bootcamp
2

Welcome on board, and thanks for the effort and honesty in following our rules. This room is here to help you out with your studies, not do the work for you and has been accepted by most colleges if rules are respected.

Not that hard, once the idea of what is expected from a sysadm: Administering a UNIX environment with users, printers, server(s) and maybe workstations...

I dealing with users: users have rights and permissions and UNIX permissions (basic) are limited to 3 cases:
the user/ownrt, a group owner, and the rest of the planet

How do you think this can be done knowing the 3 cases?
I suggest you look at the man pages of your 3 commands ls, chown, chmod
I let you start now, Im off to physio and will look and complete once back

3

417×599 58.6 KB
So, I was able to get further in the homework but now I am stuck with making the passwords be 16 characters long and ensuring that admin has general sudo access. I looked over the notes, the homework examples but I couldn't figure out how to do it for just the one person. Where should I look for this? This is also my code for the other parts.

4

What you did is give read permission to all except those in the group as the one set to this file...

5

604 permission means
r+w for owner, nothing for group, w for others!
This is very unsafe: others may alter the file!
Check with "ls -l filename".

6

Once solved the above remark I made
You can start dealing with this 2 tasks, the first we can't really help we don't know your platform, very likely linux but I am no linux specialist, all I can say is to look at you course again for clues, as what is asked will not be found in /etc/passwd or shadow file... You should have something dealing with PAM e.g. in Debian and debian based, password policies are defined in /etc/pam.d/common-password file

is sudo related, and so what you need to check/add/modify in the sudoers file using visudo , very important to use that and no other editor as it will check that there is no syntax error which would corrupt the sudoers file, I understand admin should have same as root...