[Bug 1960758] Re: UEFI libvirt servers can't boot on Ubuntu 20.04 hypervisors with Ussuri/Victoria

Mauricio Faria de Oliveira 1960758 at bugs.launchpad.net
Wed Sep 20 21:51:59 UTC 2023


Hi Corey,

While verifying (bionic) ussuri-proposed, I noticed bionic doesn't
necessarily need the fix, since its ovmf package does not ship
OVMF_CODE.secboot.fd (introduced later, present in focal).

Keeping the fix is safe, though, as it is a no-op by default (no functional change),
and may be desired to get nova in bionic-ussuri back in sync with focal, after the regression handling for CVE-2023-2088.patch, but I'm not sure of all the details involved.

I'll not mark this as verification-done-ussuri yet, in order to wait for
your confirmation.

Thanks,
Mauricio

...

Verification on bionic:

With ussuri-updates, an uefi server _does_ boot (differently than
focal):

	$ juju ssh nova-compute/0 'dpkg -s nova-compute | grep ^Version:' 2>/dev/null
	Version: 2:21.2.4-0ubuntu2.2~cloud0

	$ openstack image set jammy --property hw_firmware_type=uefi
	$ openstack server create --image jammy --flavor m1.small --network private test

	$ juju ssh nova-compute/0 sudo virsh dumpxml instance-00000001 2>&1 | sed -n '/<os>/,/<\/os>/p'
	...
	<loader readonly='yes' type='pflash'>/usr/share/OVMF/OVMF_CODE.fd</loader>
	...

	$ openstack console log show test | grep -o 'test login:'
	test login:

This works because the problematic loader (OVMF_CODE.secboot.fd) is not
yet available on bionic, only in focal:

	$ ls -1 /usr/share/OVMF/
	OVMF_CODE.fd
	OVMF_VARS.fd

	$ dpkg -S /usr/share/OVMF/OVMF_CODE.fd
	ovmf: /usr/share/OVMF/OVMF_CODE.fd

	$ dpkg -L ovmf | grep -F .fd
	/usr/share/OVMF/OVMF_CODE.fd
	/usr/share/OVMF/OVMF_VARS.fd
	/usr/share/ovmf/OVMF.fd
	/usr/share/qemu/OVMF.fd

	$ lsb_release -cs
	bionic

	$ pull-lp-debs ovmf focal
	$ dpkg-deb -c ovmf_*.deb
	...
	-rw-r--r-- root/root   1966080 2022-11-08 05:40 ./usr/share/OVMF/OVMF_CODE.secboot.fd
	...

With ussuri-proposed and new option disabled (default), an uefi server
still boots (no regression by default):

	$ juju ssh nova-compute/0 'sudo add-apt-repository --yes "deb http://ubuntu-cloud.archive.canonical.com/ubuntu bionic-proposed/ussuri main"'
	$ juju ssh nova-compute/0 'sudo apt install --yes --option=Dpkg::Options::=--force-confnew --option=Dpkg::Options::=--force-confdef nova-compute'
	$ juju ssh nova-compute/0 'sudo systemctl restart nova-compute.service' 2>/dev/null

	$ juju ssh nova-compute/0 'dpkg -s nova-compute | grep ^Version:' 2>/dev/null
	Version: 2:21.2.4-0ubuntu2.6~cloud0

	$ openstack server stop test
	$ openstack server start test

	$ juju ssh nova-compute/0 sudo virsh dumpxml instance-00000001 2>&1 | sed -n '/<os>/,/<\/os>/p'
	...
	    <loader readonly='yes' type='pflash'>/usr/share/OVMF/OVMF_CODE.fd</loader>
	...

	$ openstack console log show test | grep -o 'test login:'
	test login:

With ussuri-proposed and the new option enabled (changed), an uefi
server still boots (no regression)

	$ juju config nova-compute config-flags='ubuntu_libvirt_uefi_loader_path=True'
	$ juju ssh nova-compute/0 sudo grep ubuntu_libvirt_uefi_loader_path /etc/nova/nova.conf 2>/dev/null
	ubuntu_libvirt_uefi_loader_path = True

	$ openstack server stop test
	$ openstack server start test
	$ juju ssh nova-compute/0 sudo virsh dumpxml instance-00000001 2>&1 | sed -n '/<os>/,/<\/os>/p'
	...
	    <loader readonly='yes' type='pflash'>/usr/share/OVMF/OVMF_CODE.fd</loader>
	...

	$ openstack console log show test | grep -o 'test login:'
	test login:


** CVE added: https://cve.mitre.org/cgi-bin/cvename.cgi?name=2023-2088

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https://bugs.launchpad.net/bugs/1960758

Title:
  UEFI libvirt servers can't boot on Ubuntu 20.04 hypervisors with
  Ussuri/Victoria

Status in Ubuntu Cloud Archive:
  Invalid
Status in Ubuntu Cloud Archive ussuri series:
  Fix Committed
Status in Ubuntu Cloud Archive victoria series:
  Fix Released
Status in OpenStack Compute (nova):
  Invalid
Status in OpenStack Compute (nova) ussuri series:
  Invalid
Status in OpenStack Compute (nova) victoria series:
  Invalid
Status in nova package in Ubuntu:
  Invalid
Status in nova source package in Focal:
  Fix Released

Bug description:
  Impact:
  ===

  Currently, setting `hw_firwmare_type=uefi` may create
  _unbootable_ servers on 20.04 hypervisors with Ussuri
  and Victoria (Wallaby and later are OK).

  We should not use the Secure Boot firmware on the 'pc'
  machine type, as 'q35' is _required_ by OVMF firmware
  if SMM feature is built (usually the case, to actually
  secure the SB feature).
  [See comment #6 for research and #7 for test evidence.]

  We should not use the Secure Boot firmware on the 'q35'
  machine type _either_, as it might not work regardless,
  since other libvirt XML options such as SMM and S3/S4
  disable may be needed for Secure Boot to work, but are
  _not_ configured by Openstack Ussuri (no SB support).

  
  Approach:
  ===

  Considering how long Focal/Ussuri have been out there
  (and maybe worked with UEFI enabled for some cases?)
  add a config option to _opt-in_ to actually supported
  UEFI loaders for nova/libvirt.

  This seems to benefit downstream/Ubuntu more (although
  other distros might be affected) add the config option
  "ubuntu_libvirt_uefi_loader_path" (disabled by default)
  in the DEFAULT libvirt config section (so it can be set
  in nova-compute charm's 'config-flags' option).

  
  Test Plan:
  ===

  $ openstack image set --property hw_firmware_type=uefi $IMAGE
  $ openstack server create --image $IMAGE --flavor $FLAVOR --network $NETWORK uefi-server

  (with patched packages:)
  Set `ubuntu_libvirt_uefi_loader_path = true` in `[DEFAULT]` in /etc/nova/nova.conf
  (eg `juju config nova-compute config-flags='ubuntu_libvirt_uefi_loader_path=true'`)
  $ openstack server stop uefi-server
  $ openstack server start uefi-server

  - Expected Result:

  The server's libvirt XML uses UEFI _without_ Secure Boot.

          <loader readonly='yes'
  type='pflash'>/usr/share/OVMF/OVMF_CODE.fd</loader>

  The guest boots, and console log confirms UEFI mode:

          $ openstack console log show srv | grep -i -e efi -e bios
          ...
          Creating boot entry "Boot0003" with label "ubuntu" for file "\EFI\ubuntu\shimx64.efi"
          ...
          [    0.000000] efi: EFI v2.70 by EDK II
          [    0.000000] efi:  SMBIOS=0x7fbcd000  ACPI=0x7fbfa000  ACPI
          2.0=0x7fbfa014  MEMATTR=0x7eb30018
          [    0.000000] SMBIOS 2.8 present.
          [    0.000000] DMI: OpenStack Foundation OpenStack Nova, BIOS 0.0.0 02/06/2015
          ...

  - Actual Result:

  The server's libvirt XML uses UEFI _with_ Secure Boot.

          <loader readonly='yes'
  type='pflash'>/usr/share/OVMF/OVMF_CODE.secboot.fd</loader>

  The guest doesn't boot; empty console log; qemu-kvm looping at 100%
  CPU.

          $ openstack console log show srv | grep -i -e efi -e bios
          $ openstack console log show srv | wc -l
          0

          $ juju run --app nova-compute 'top -b -d1 -n5 | grep qemu'
            67205 libvirt+  ... 100.0   1.4   1:18.35 qemu-sy+
            67205 libvirt+  ... 100.0   1.4   1:19.36 qemu-sy+
            67205 libvirt+  ...  99.0   1.4   1:20.36 qemu-sy+
            67205 libvirt+  ... 101.0   1.4   1:21.37 qemu-sy+
            67205 libvirt+  ... 100.0   1.4   1:22.38 qemu-sy+

  
  Where problems could occur:
  ===

  The changes are opt-in with `ubuntu_libvirt_uefi_loader_path=true`,
  so users are not affected by default.

  Theoretically, regressions would more likely manifest and be contained
  in nova's libvirt driver, when `hw_firwmare_type=uefi` (not by default).

  The expected symptoms of regressions are boot failures (server starts
  from openstack perspective, but doesn't boot to the operating system).

  
  Other Info:
  ===

  - Hypervisor running Ubuntu 20.04 LTS (Focal)
  - Nova packages from Ussuri (Ubuntu Archive) or Victoria (Cloud Archive).

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