File and System Security

The goal of computer security is the protection of information stored on the computer system, a valuable resource. Information security is aimed at the following:

It is helpful to plan and implement your security policies before you begin using the system. Security policies are very time-consuming to change later, so upfront planning can save a lot of time later.

This chapter discusses the following:

• Security Threats
• File Ownership and User Groups
  • Changing File or Directory Ownership (chown Command)
  • File and Directory Access Modes
  • Displaying Group Information (lsgroup Command)
  • Changing File or Directory Permissions (chmod Command)
• Access Control Lists
  • Base Permissions
  • Extended Permissions
  • Access Control List Example
  • Access Authorization
  • Displaying Access Control Information (aclget Command)
  • Setting Access Control Information (aclput Command)
  • Editing Access Control Information (acledit Command)
• Locking Your Terminal (lock or xlock Command)
• Command Summary for File and System Security