Wednesday, March 25, 2020

Little Snitch and the Deprecation of Kernel Extensions

Rich Trouton:

As part of macOS Catalina 10.15.4, Apple has begun displaying a new dialog window message concerning third-party kernel extensions.


To further reinforce the message that kernel extensions are going away, Apple refers to them in the message window as “legacy system extensions”.


For a number of managed environments, these messages can be prevented from appearing. As long as a third-party kernel extension is whitelisted using an appropriate configuration profile, the message for it should not appear.

Norbert Heger (Hacker News):

We expect the deprecation to become effective with the next major release of macOS. There’s no official release date from Apple, but based on the release schedule of recent years it will not be before this fall. Little Snitch 4 will then not be loaded by the operating system, but there will still be an option to allow the loading.


The replacement APIs that are currently available (NetworkExtension framework on macOS 10.15.4) are not yet completely sufficient to implement the full functionality of Little Snitch. But we are working closely with Apple to fill the remaining gaps and we expect that a beta of the next major macOS version (most likely available at the next WWDC) or even an upcoming version of 10.15 will provide what is missing. As soon as the APIs allow us, we will complete the transition of Little Snitch to the new NetworkExtension API. It’s our goal to provide a public beta in June 2020 and a stable version in October.


Update (2020-03-27): Greg Hurrell:

I sure hope this doesn’t end up breaking Karabiner-Elements. If I had to use a machine without it, it would seriously impact usability for me. When the day comes that Apple breaks kernel extensions once and for all, I’ll be holding off on OS updates for as long as I can.

Adam Engst:

Unfortunately, since the dialogs give only the developers’ names, not the names of their apps, it’s difficult to know who I might contact. A Google search revealed that Ludovic Leger is the dev lead on TripMode, a useful utility I recommend for managing bandwidth use while away from high-speed networks; see “TripMode Prevents Unwanted Internet Data Usage on a Tethered Mac” (22 July 2015). I’m still not sure who Steven Yan is, or what app of his I might be using. That’s not a problem now, but it might be in a few months once the beta of whatever macOS version follows Catalina comes out.

Update (2020-06-05): Takayama Fumihiko:

Current status of Karabiner-Elements: I’m working to both DriverKit virtual keyboard and pure software keyboard using IOHIDSystem.

The IOHIDSystem library is re-implemented which was used in old Karabiner-Elements.

Update (2021-07-26): Patrick Wardle:

🙋‍♂️Who’s frustrated by Apple deprecating APIs only to provide a broken replacement!?

Several years ago NKEs were deprecated.

This forced devs to rewrite their tools to use Apple’s new (buggy) Network Extensions ...and since then deal w/ a deluge of user-submitted bug reports😭

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