network system extension + Safari 17.1.2 BREAKS protocol stack

Someone else may want to test this with their network system extension, but I found a nasty interaction with Apple's latest software update for Safari and my network system extension.

Summary: When I had my network system extension installed and updated to Safari 17.1.2, all networking was lost.

I first ran into this problem yesterday and documented in this thread. Today, I tried to pin it down on Ventura.

This test

• Hardware: M1 Mac mini
• OS: macOS Ventura 13.6.1 (downloaded from Mac App Store)
• Safari version 16.6
• Network system extension (mine)

When I updated to Safari Version 17.1.2, I lost all networking!

Furthermore, I could not uninstall my network extension. Deleting the app with the network system extension didn't help.

Fix 1:

1. Disabled SIP
2. Removed my network system extension (at which point networking worked fine again)
3. Reenabled SIP
4. Reinstalled my network system extension

Everything works fine.

Fix 2

I re-ran the experiment (same initial set up)

• Hardware: M1 Mac mini
• OS: macOS Ventura 13.6.1 (downloaded from Mac App Store)
• Safari version 16.6
• Network system extension (mine)

This time:

1. I removed my network system extension first
2. I updated to Safari 17.1.2 (this time no problems)
3. I reinstalled my network system extension

Everything works fine

Having the network system extension in place and then updating Safari to 17.1.2 broke things pretty badly for me.

Was there something I did wrong with my network system extension design?