[SOLVED] Libvirt - Normal User Lost Permissions to virbr0

[Perdignus]

I emerged/upgraded world this morning and installed the 4.20.10 kernel, rebooted and my libvirt VM running as a normal user and using virbr0 was unable to start with a complaint about "failed to communicate with bridge helper".

I figured it was due to a new version and I was on ~amd64 version 5.0.0, so I disabled ~amd64 and went back to version 4.9.0 but that didn't help so I figured it was the new kernel so I went back to 4.20.5 but that also didn't help.

I now have the VM running as root using virbr0 but I'm just confused about why access to virbr0 stopped working for my normal account.

My /etc/qemu/bridge.conf didn't change and I have "allow virbr0" in it and my normal user belongs to the qemu group.

Here's the exact error:

Error starting domain: internal error: /usr/libexec/qemu-bridge-helper --use-vnet --br=virbr0 --fd=20: failed to communicate with bridge helper: Transport endpoint is not connected
stderr=failed to create tun device: Operation not permitted


Thanks,
Perdignus.

[DevLinux]

Not sure if you've found your answer, but I ran into this tonight, so I'm posting the answer just in case somebody else runs into this.

Apparently, the qemu update overwrites the file and doesn't reset the permission.

To fix the problem, run the following:

[DevLinux]

I also found this after posting the above which also looks to be relevant.

https://bugs.gentoo.org/677152

[Perdignus]

Nice find! That did the trick and resolved the issue for me. Thanks you very much for the followup post.

Patrick.