Mac OS Karabiner: The Power of Kernel Extensions

For years, Apple has encouraged third-party developers to move away from kernel extensions in favor of user-level equivalents. This shift was prompted by the realization that kernel extensions can cause problems such as system crashes, conflicts with other software, and security vulnerabilities. However, it has only been in the last year or so that Apple has provided sufficient support for this transition.

Kernel extensions have long been a powerful and dangerous feature of macOS. They operate at a high level of privilege, allowing them to interact directly with hardware devices such as Ethernet and Thunderbolt ports. This makes them an attractive target for malicious developers who seek to install their own kernel extensions or modify existing ones.

In Big Sur, the kernel has just over 550 standard kernel extensions that enable it to function properly. Early versions of Mac OS X loaded these extensions individually, which made the boot process slow and tedious. Today, Apple prelinks the kernel with all its extensions, making loading much quicker but also putting kernel extensions in an even more privileged position.

Kernel extensions are essential for supporting the wide range of hardware available on Macs, both within and connected to them. They enable developers to add new features such as software firewalls and security protection, and modify the behavior of macOS by rerouting sound output to apps and so on.

In conclusion, kernel extensions have long been a powerful feature of macOS, but they also pose significant risks. As Apple continues to develop its operating system, it is important for developers to be aware of these risks and take steps to mitigate them.

Mac os karabiner