Security

Security is one of the most important point of Karabiner-Elements architecture design.

Separating process and running them with properly privileges to prevent event leaks.

Process

Karabiner-Elements restricts the input event handling to karabiner_observer and karabiner_grabber processes.

These process are running with root privilege and other process including malicious attacker cannot steal your input events.

List of process

Running with root privilege

• karabiner_observer
  • Role:
    • Observe the keyboard hardware events and tell grabber the devices state.
• karabiner_grabber
  • Role:
    • Grab the keyboard hardware and catch events, modify events then post them.
• Karabiner VirtualHIDDevice kernel extension
  • Role:
    • Virtual keyboard and pointing device.
    • The virtual devices deny any requires (sending input events) from non root privileged processes.
      Typically, karabiner_grabber is the only process which can send input events to the virtual devices.

Running with logged in user privilege

• karabiner_console_user_server
  • Role:
    • Tell karabiner_grabber starting device grabbing.
    • Execute shell commands which is triggered by karabiner_grabber.
• karabiner_session_monitor
  • Role:
    • Monitor user login status and tell it to karabiner_grabber.
• karabiner_observer (Running with logged in user)
  • Role:
    • Tell macOS karabiner_observer will be use Input Monitoring.
      And do nothing if the process is running with non root user.
• karabiner_grabber (Running with logged in user)
  • Role:
    • Tell macOS karabiner_grabber will be use Input Monitoring.
      And do nothing if the process is running with non root user.