Control Application Access

TL;DR

Use operating system user accounts and permissions to control who can run your application. For more complex scenarios, consider access control lists (ACLs) or dedicated authentication/authorization systems.

1. Operating System User Accounts

The simplest way is to rely on the built-in user account system of your operating system (Windows, macOS, Linux). Each user has an account with specific permissions.

• Create Users: Create separate user accounts for each person who needs access. Avoid sharing accounts!
• Permissions: Grant only the necessary permissions to each user. For example, if someone only needs to run your application, don’t give them administrator/root privileges.

On Linux:

sudo adduser newuser

On Windows (using Command Prompt as Administrator):

net user newuser password /add

2. File Permissions

Control access to the application executable and any related files.

• Linux/macOS: Use chmod to set permissions. For example, to allow only the owner to execute:

chmod 700 /path/to/your/application

(This means user has read, write and execute; group and others have no access.)

Windows: Right-click the file, select ‘Properties’, go to the ‘Security’ tab. Edit permissions for each user or group.

3. Access Control Lists (ACLs)

For finer-grained control than basic file permissions, use ACLs.

• Linux: Use setfacl and getfacl to manage ACLs. Example:

setfacl -m u:newuser:rwx /path/to/your/application

(This gives user ‘newuser’ read, write, and execute permissions.)

Windows: ACLs are managed through the Security tab in file properties (as described above).

4. Authentication & Authorization Systems

For applications requiring more complex security (e.g., multiple roles, web-based access), use a dedicated system.

• Built-in OS Features: Windows Active Directory provides robust authentication and authorization.
• Third-Party Libraries/Frameworks: Many programming languages have libraries for handling authentication (verifying identity) and authorization (checking permissions). Examples include OAuth 2.0, OpenID Connect, or role-based access control (RBAC) frameworks.

5. Application-Level Checks

Even with OS-level controls, it’s good practice to add checks *within* your application.

• User Identification: Identify the current user running the application (e.g., using environment variables or OS APIs).
• Permission Checks: Before performing sensitive operations, verify that the user has the necessary permissions.

6. Consider Containerization

Using containers (like Docker) can add another layer of security.

• Limited Privileges: Run your application within a container with limited privileges. This reduces the impact if the application is compromised.
• User Mapping: Map users inside the container to specific OS users, further controlling access.