Capability-based security in Operating Systems - Mini Project: Build & Apply

Understanding Capability-based Security

📖 Scenario: You are learning about how computers control access to resources like files and devices. Capability-based security is a way to manage permissions by giving specific 'capabilities' or keys to users or programs.Imagine a library where each visitor has a special card that lets them borrow certain books. This card is like a capability that grants access only to allowed books.

🎯 Goal: Build a simple model of capability-based security using a dictionary to represent users and their capabilities. Then, check if a user has permission to access a resource.

📋 What You'll Learn

Create a dictionary named user_capabilities with exact user names and their capability lists

Create a variable named resource with the exact resource name to check

Write a loop using for user, capabilities in user_capabilities.items() to find users with access to the resource

Add a final statement that stores the list of users who can access the resource in a variable named authorized_users

💡 Why This Matters

🌍 Real World

Capability-based security is used in operating systems and software to control access to files, devices, and services by giving specific permissions to users or programs.

💼 Career

Understanding capability-based security helps in roles like system administration, security engineering, and software development where managing access control is critical.

1

Create the user capabilities dictionary

Create a dictionary called user_capabilities with these exact entries: 'alice': ['read', 'write'], 'bob': ['read'], and 'carol': ['execute'].

Operating Systems

# Create the user_capabilities dictionary with exact entries
# Your code here

Need a hint?

Use curly braces {} to create a dictionary. Each key is a user name string, and each value is a list of capability strings.

2

Set the resource to check

Create a variable called resource and set it to the string 'read' to represent the capability you want to check.

Operating Systems

user_capabilities = {
    'alice': ['read', 'write'],
    'bob': ['read'],
    'carol': ['execute']
}
# Create the resource variable with value 'read'
# Your code here

Need a hint?

Assign the string 'read' to the variable resource.

3

Find users with the capability

Use a for loop with variables user and capabilities to iterate over user_capabilities.items(). Inside the loop, check if resource is in capabilities and collect those users in a list called authorized_users.

Operating Systems

user_capabilities = {
    'alice': ['read', 'write'],
    'bob': ['read'],
    'carol': ['execute']
}
resource = 'read'

# Initialize authorized_users as an empty list
authorized_users = []

# Use a for loop to find users with the 'read' capability
# Your code here

Need a hint?

Use for user, capabilities in user_capabilities.items(): to loop. Check if resource is in capabilities. If yes, add user to authorized_users.

4

Complete the authorized users list

Ensure the variable authorized_users contains the list of users who have the resource capability. This completes the capability check.

Operating Systems

user_capabilities = {
    'alice': ['read', 'write'],
    'bob': ['read'],
    'carol': ['execute']
}
resource = 'read'

# authorized_users list is ready
# Your code here if needed

Need a hint?

The list authorized_users should have all users who can 'read'. No extra code needed if previous step is correct.