Thanks Seth and Robert,
I'll follows Seth advise and for now propose (B) being the fix for libvirt.
But I'll add a task for apparmor (which carries abstraction/namespace) as that
still might be an avenue worthwhile to follow independent to this libvirt fix.
If more people speak up or we find more cases affected then adding it there
eventually seems good.
** Also affects: apparmor (Ubuntu)
Importance: Undecided
Status: New
** Changed in: apparmor (Ubuntu)
Status: New => Invalid
** Changed in: libvirt (Ubuntu)
Status: Fix Released => Invalid
** Changed in: libvirt (Ubuntu Focal)
Assignee: Ubuntu Security Team (ubuntu-security) => (unassigned)
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https://bugs.launchpad.net/bugs/1890858
Title:
AppArmor profile causes QEMU/KVM - Not Connected
Status in apparmor package in Ubuntu:
Invalid
Status in libvirt package in Ubuntu:
Invalid
Status in apparmor source package in Focal:
New
Status in libvirt source package in Focal:
Triaged
Bug description:
[Impact]
* libvirt in Focal in some cases e.g. with non local users
needs to resolve those users. When trying to do so it fails
due to apparmor isolation and breaks badly.
* In later and former releases this issue isn't triggered,
but it is unknown which (potentially complex) set of changes
did that. A simple apparmor rule would help to allow libvirt
to better function in environments with non known user IDs.
[Test Plan]
* Following these steps in an unfixed release triggers the issue
sudo apt update; sudo apt dist-upgrade -y
sudo apt install -y sssd sssd-ldap slapd ldap-utils openssl expect
lsb-release libvirt-clients libvirt-daemon-system ubuntu-dev-tools
pull-lp-source sssd
cd sssd-2.4.1
echo "*;*;*;Al0000-2400;libvirt" | sudo tee -a /etc/security/group.conf
head -n -5 debian/tests/ldap-user-group-ldap-auth >
debian/tests/lp1890858-test
chmod +x debian/tests/lp1890858-test
sudo ./debian/tests/lp1890858-test
sudo systemctl restart libvirtd
# ensure it works in a normal login
virsh list
journalctl -u libvirtd
# try the sssd login
sudo login
# use testuser1 / testuser1secret to log in
virsh list
If affected this will not work reporting an error like:
$ virsh list
error: failed to connect to the hypervisor
error: End of file while reading data: Input/output error
And in dmesg/journal an apparmor denial like:
Jun 14 11:25:26 ldap.example.com audit[48330]: AVC apparmor="DENIED"
operation="bind" profile="libvirtd" pid=48330 comm="rpc-worker"
family="unix" sock_type="dgram" protocol=0 requested_mask="bind"
denied_mask="bind" addr="@userdb-f283d575d74df972f9e10bd14d0befe3"
[Where problems could occur]
* Allowing a little bit more to a daemon that already is rather powerful
and open in regard to it's profile usually isn't changing behavior.
If anything it would be considered a potential risk, but this rule
should be ok to be added and ubuntu-security confirmed this.
[Other Info]
* Comment 38 confirms that this should be ok - from the security Teams
POV.
https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/1890858/comments/38
---
On some focal 20.04 systems, users are seeing "QEMU/KVM - Not
Connected" when they attempt to use virt-manager to manage virtual
machines. AppArmor denials like the following are seen in the logs:
sudo grep libvirt /var/log/syslog | grep -i apparmor | grep -i denied
Jun 28 14:53:27 koromicha kernel: [ 334.660844] audit: type=1400
audit(1593345207.778:951): apparmor="DENIED" operation="bind"
profile="libvirtd" pid=12254 comm="libvirtd" family="unix" sock_type="dgram"
protocol=0 requested_mask="bind" denied_mask="bind"
addr="@userdb-6228daaaf66b14dfd14d93ef46d962c3"
Jun 28 14:54:19 koromicha kernel: [ 386.034970] audit: type=1400
audit(1593345259.145:952): apparmor="DENIED" operation="bind"
profile="libvirtd" pid=14311 comm="libvirtd" family="unix" sock_type="dgram"
protocol=0 requested_mask="bind" denied_mask="bind"
addr="@userdb-c861507740da1fa0c3356ad3b78bffe9"
Jun 28 15:02:30 koromicha kernel: [ 877.339057] audit: type=1400
audit(1593345750.437:968): apparmor="DENIED" operation="bind"
profile="libvirtd" pid=16175 comm="libvirtd" family="unix" sock_type="dgram"
protocol=0 requested_mask="bind" denied_mask="bind"
addr="@userdb-7d70643a9f8da0342f6359907817b664"
Users have reported that the "solution" is to disable the AppArmor
profile. More details, screenshots, etc. can be found here:
https://kifarunix.com/how-to-fix-qemu-kvm-not-connected-error-on-
ubuntu-20-04/
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/apparmor/+bug/1890858/+subscriptions
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