RHCSA – Exam objectives – Create and configure set-GID directories for collaboration

RHCSA – Exam objectives – User and Directory permissions

One of the RHCSA exam objectives is to share a directory among users and setting up right permissions.

Scenario

Configure the following users for RHEL: nancy, randy, donna, and mike. Make nancy and randy part of a group named angels. Create a /home/angels directory and allow them to share files without having to change permissions or ownership on any file they put in this directory. Do not give donna or mike read privileges on this directory

Solution

1.       Create a directory ‘angels’ under home directory

#mkdir /home/angels

2.       Create 4 users nancy, randy, donna and mike

#useradd nancy; useradd randy; useradd donna; useradd mike

3.       Create a group called angels and add users nancy and randy.

#groupadd angles

#usermod –G angels nancy; usermod –G angels randy

Or edit /etc/group and add users nancy, randy to group angels.

4.       Change permissions on directory /home/angels

#chmod  -R 2770 /home/angels

#chown –R nobody:angles /home/angels

#ls –lh /home/angels

drwxrws---.  2 nobody      angels      4.0K Feb 13 10:01 angels

The directory permissions are now changed to group ‘angels’ and owner is changed to ‘nobody’. Group users other than ‘angels’ cant’ get access to /home/angels directory

5.       Test the scenario

Under user randy create a file named test_file in /home/angles directory

If you cannot create a file, then there may a issue with permissions. Check /home directory permissions.

Test with user randy.

Login to nancy account, and open the file created by user nancy. Any error means group permissions are not properly set. Check /etc/group file and look for group angels.

Nancy can also edit/write the same file

Users donna and mike shouldn’t get access to directory /home/angels

Both users must get deny messages.

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