Practical Linux Security Cookbook

Implementing access control list (ACL)

Implementing the basic file permissions using chmod is not enough, so we can use ACLs. In addition to providing permissions for the owner and group of a particular file, we can set permissions for any user, user group, or group of all the users who are not in a group of a particular user using ACLs.

Getting ready

Before starting with the setting of permissions using ACLs, we need to confirm whether ACLs are enabled or not. We can do this by trying to view the ACLs for any file, as shown in this example:

getfacl<filename>

The preceding command will show an output similar to the following if the ACLs are enabled:

How to do it…

To understand more about ACLs, let's perform these steps:

1. First, we will create three users ...