22.10 beta: v4l2loopback key was rejected by modprobe

[Waldo]

Using amd64 version of new 22.10 beta. When I

sudo modprobe v4l2loopback [stuff]

I get:

modprobe: ERROR: could not insert 'v4l2loopback': Key was rejected by service

Looks like a signature issue. Secure boot is on.

Relevant packages involved:

ii v4l2loopback-dkms 0.12.7-2ubuntu1 all Source for the v4l2loopback driver (DKMS)
ii linux-image-5.19.0-15-generic 5.19.0-15.15 amd64 Signed kernel image generic

Should not need to self-sign this. At least didn't in 22.04.

Tried removing/reinstalling but no success.

Cheers!

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Blaze (blaze)]

It is not specific for v4l2loopback. You can reproduce this issue with any dkms module, ie iwlwifi-dkms or virtualbox-dkms

[Waldo (vvaldo)]

.... and nvidia-dkms-515 as I just discovered.

This needs to get fixed quick.

[Waldo (vvaldo)]

So nvidia-dkms worked in secure boot once I switched drivers away from and then back to nvidia-515.

As for v4l2loopback-dkms -- I tried to install --reinstall, but that didn't work.

Then I noticed here that other packages were actually already providing v4l2loopback:

https://packages.ubuntu.com/kinetic/v4l2loopback-dkms

so I tried just removing it:

sudo apt purge v4l2loopback-dkms

This resulted in other packages not being needed, which I removed with apt autoremove:

  dctrl-tools dh-dkms dkms

Then tried to modprobe v4l2loopback and it worked!

So I'm guessing i must have had it installed 2x-- as it was, in my case, already provided by:

linux-image-5.19.0-21-generic

Hope this helps anyone who's encountered this issue.

tl;dr -- I had v4l2loopback-dkms manually installed in 22.04, but apparently it's not needed any more in 22.10 and actually messes things up in secure boot mode, so apt purge it.

[Marian Rainer-Harbach (marianrh)]

I guess this is a duplicate of bug #1991725.

[Jorge Pérez Lara (jorgesgk)]

Please check this solution: It worked for me for the broadcom wl.ko module. Maybe it may work for your module too?

https://discourse.ubuntu.com/t/dkms-package-support-extra-drivers-does-not-work-in-ubuntu-22-10-install-media/31655

There's a typo, though. The command should be:

sudo kmodsign sha512 /var/lib/shim-signed/mok/MOK.priv /var/lib/shim-signed/mok/MOK.der /lib/modules/5.19.0-23-generic/updates/dkms/wl.ko