iwd on Ubuntu 20.04 stopped working since update to kernel 5.11

[alkatraz]

I was using iwd on my Acer aspire v17 nitro with Ubuntu 20.04, and it was working great. But after the last update to kernel 5.11 it suddenly had stopped working. I’ve tried to reinstall it but that didn’t help. I've tried back with kernel 5.8 and iwd was working again. Quick google search showed that this is actually a wide spread problem since kernel 5.9.x, so I wish to ask is there going to be a solution of any kind?
Regards!
I.Ivanov
---
ProblemType: Bug
ApportVersion: 2.20.11-0ubuntu27.18
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
DistroRelease: Ubuntu 20.04
InstallationDate: Installed on 2021-07-28 (6 days ago)
InstallationMedia: Ubuntu 20.04.2.0 LTS "Focal Fossa" - Release amd64 (20210209.1)
NonfreeKernelModules: nvidia_modeset nvidia
Package: iwd 1.5-1
PackageArchitecture: amd64
ProcVersionSignature: Ubuntu 5.11.0-25.27~20.04.1-generic 5.11.22
Tags: focal
Uname: Linux 5.11.0-25-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin lxd plugdev sambashare sudo
_MarkForUpload: True

[lotuspsychje (lotuspsychje)]

Thank you for reporting this bug and make Ubuntu better!

Please run apport-collect 1938650 from a terminal in order to
pull relevant info into this bug so developers can debug a better way.

[alkatraz (hellion-bg)]

apport information

[alkatraz (hellion-bg)]

apport information

[alkatraz (hellion-bg)]

apport information

[A B Steel (phast7)]

i can confirm, iwd isn't working on 5.11 kernel on fossa.

$ /usr/libexec/iwd
RC4 support not found
The following options are missing in the kernel:
 CONFIG_CRYPTO_USER_API_SKCIPHER
 CONFIG_CRYPTO_ECB
 CONFIG_CRYPTO_ARC4

$ cat /boot/config-5.11.0-25-generic | grep CONFIG_CRYPTO_ARC4
$

[Launchpad Janitor (janitor)]

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

[A B Steel (phast7)]

i used slyon's repo from here

https://launchpad.net/~slyon/+archive/ubuntu/iwd+nm

and updated iwd+nm
that fixed the bug for me.

should be pushed upstream i guess.

[alkatraz (hellion-bg)]

@A B Steel
Using untrusted ppa is not the proper way of doing things I guess. Nevertheless I can confirm that using this repository solved the issue and iwd - at least for the time being, is now working.

[A B Steel (phast7)]

Lukas called for testing here, so probably he can push it to upstream.

https://discourse.ubuntu.com/t/call-for-testing-improved-wifi-via-iwd/17795

[alkatraz (hellion-bg)]

Yes, I know. I did had posted the issue there first :)

[Oleksandr Korsun (koralex)]

The same for me. It doesn't work with 5.11 kernel and works with 5.8.

[Lukas Märdian (slyon)]

This seems to be a regression (deprecated AF_ALG RC4 support) in the linux-hwe-5.11 stack: https://lkml.org/lkml/2020/8/4/512

A workaround exists by either using Linux 5.8 or using a newer iwd version (e.g. from https://launchpad.net/~slyon/+archive/ubuntu/iwd+nm )

Unfortunately, we cannot easily backport a big version jump of iwd into the 20.04 stable series, but we would need a small patch that only backports the required iwd RC4 implementation on top of iwd-1.5.

[alkatraz (hellion-bg)]

@Lukas Märdian (slyon),
I've understand that, but since 20.04 is the defacto LTS release right now I think a fix, besides using an untrusted repository, would be much appreciated by the mainstream users.
Cheers!

[Launchpad Janitor (janitor)]

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