Pos/355 - Week 2 - Linux File Access

File Access

University of Phoenix

Introduction to Operating Systems POS355

James Welti Jr

File Access

The Linux operating system contains a file access permissions configuration used to control the who can read, write, and execute a certain file (Linux file access permissions reference, n.d.). The file access permissions are critical to security of a file to allow or not allow certain people to have access to particular files on the system they are accessing.

The Linux permission model lets an administrator to specify permissions for the file's owner, a group, and others (also known as the universe) (Leung, 2007). The basic file permission can satisfy some models but the most common recent approach is to combine the basic file permission with Access Control Lists (ACL) (Silberschatz, Galvin, & Gagne, 2012). The ACL feature of Linux combined with the basic file permissions provides for a much finer control for file access than the basic permissions.

With the ACL, you can specify access to files contents for an individual user or a group of users defined in the system. There are two different types of ACL settings, one that specifically defines a group and a default ACL for other users not specified in any of the groups defined already in the access to the file. An ACL would be a proper way for setting file access controls when considering a system that supports 5,000 users, and you only want to allow 4,990 of these users to be able to access one file. In this example, the ACL could be configured two different ways to allow access to a file.

The first way of setting the file access permissions in the ACL would be to create a group of people who can access the file. This would require creating a group of all 4,990 people who can use the file and changing the permissions so this group can access the file. A Network Administrator would manage this and if another person needs access to this file they would need to be added to the...