Insufficient xen virtual machine validation

[Alex Moldovan]

Landscape-client allows registration of a bare-metal machine using a "Virtual" type license when xen-hypervisor is running.

To reproduce:

1) Install the latest xen-hypervisor package available on a bare-metal machine.
2) Reboot. Grub will automatically boot with Ubuntu with Xen hypervisor.
3) Register the machine.

Since xen is now running and the client checks for for path in "proc/xen", it's detected as being a xen virtual machine.

From broker.log:

'messages': [{'account_name': u'example',
               'api': '3.3',
               'computer_title': u'bare-metal',
               'container-info': u'',
               'hostname': u'intel',
               'registration_password': u'passwd',
               'tags': None,
               'timestamp': 1468015877,
               'type': 'register',
               'vm-info': 'xen'}],

[Eric Desrochers (slashd)]

Current piece of code related to "Xen" in landscape-client.

 22 if _is_vm_xen(root_path):
 23 return "xen"
 ....
 40 def _is_vm_xen(root_path):
 41 """Check if the host is virtualized with Xen."""
 42 xen_paths = [
 43 os.path.join(root_path, path)
 44 for path in ("proc/sys/xen", "proc/xen")]
 45
 46 if filter(os.path.exists, xen_paths):
 47 return True
 48
 49 # /sys/bus/xen exists on most machines, but only virtual machines have
 50 # devices
 51 sys_xen_path = os.path.join(root_path, "sys/bus/xen/devices")
 52 return os.path.isdir(sys_xen_path) and os.listdir(sys_xen_path)
 53
 54

Maybe a validation based on "dmidecode" output might be more accurate ?

$ dmidecode | grep -i domU
Product Name: HVM domU

There is also virt-what that already does that kind of validation.
Maybe that could be use as a reference.

# virt-what-1.13/virt-what.in
--
190 # Check for Xen.
191
192 if [ "$cpuid" = "XenVMMXenVMM" ]; then
193 echo xen; echo xen-hvm
194 skip_qemu_kvm=true
195 elif [ -f "${root}/proc/xen/capabilities" ]; then
196 echo xen
197 if grep -q "control_d" "${root}/proc/xen/capabilities"; then
198 echo xen-dom0
199 else
200 echo xen-domU
201 fi
202 skip_qemu_kvm=true
203 elif [ -f "${root}/sys/hypervisor/type" ] &&
204 grep -q "xen" "${root}/sys/hypervisor/type"; then
205 # Ordinary kernel with pv_ops. There does not seem to be
206 # enough information at present to tell whether this is dom0
207 # or domU. XXX
208 echo xen
209 elif [ "$arch" = "ia64" ]; then
210 if [ -d "${root}/sys/bus/xen" -a ! -d "${root}/sys/bus/xen-backend" ]; then
211 # PV-on-HVM drivers installed in a Xen guest.
212 echo xen
213 echo xen-hvm
214 else
215 # There is no virt leaf on IA64 HVM. This is a last-ditch
216 # attempt to detect something is virtualized by using a
217 # timing attack.
218 virt-what-ia64-xen-rdtsc-test > /dev/null 2>&1
219 case "$?" in
220 0) ;; # not virtual
221 1) # Could be some sort of virt, or could just be a bit slow.
222 echo virt
223 esac
224 fi
225 fi
--

Eric

[Eric Desrochers (slashd)]

The more I read about it, and the more I think the most efficient way to approach this would be to use the cpuid (CPU Identification) just like virt-what does.

The following are known ID strings from virtual machines:

"KVMKVMKVM" – KVM
"Microsoft Hv" – Microsoft Hyper-V or Windows Virtual PC
" lrpepyh vr" – Parallels (it possibly should be "prl hyperv ", but it is encoded as " lrpepyh vr")
"VMwareVMware" – VMware
"XenVMMXenVMM" – Xen HVM

[Eric Desrochers (slashd)]

# On Baremetal where the XEN guest reside #

$ virt-what
xen
xen-dom0

# On XEN guest #

$ virt-what
xen
xen-hvm

Landscape-team, do you think including virt-what as a package dependency during landscape-client installation and use virt-what for detection might be a viable solution ?

This also could be expanded to other virt types : kvm, xen, vmware, Hyper-V, et al.

Eric

[Alberto Donato (ack)]

@Eric, we can't depend landscape-client on virt-what since it's in universe.
I guess we can borrow logic from it.

[Launchpad Janitor (janitor)]

This bug was fixed in the package landscape-client - 18.01-0ubuntu1

---------------
landscape-client (18.01-0ubuntu1) bionic; urgency=medium

  * New upstream release 18.01:
    - Ported to python3 (LP: #1577850)
    - move Replaces/Breaks landscape-client-ui rules to landscape-common
      (LP: #1560424)
    - Add a libpam-systemd Depends if built for xenial (LP: #1590838)
    - Some units not reporting swift usage (LP: #1588404)
    - Fix missing install directories for landscape-common and drop
      usr/share/landscape as its only used and created by landscape-client.
      (LP: #1680842)
    - Fix VM detection for Xen, by returning "xen" only for paravirtualized and
      HVM hosts, not for dom0. (LP: #1601818)
    - Add an indication of truncation to process output that has been truncated
      prior to delivery to the server. (LP: #1629000)
    - add /snap/bin to the PATH when executing scripts. (LP: #1635634)
    - Save the original sources.list file when a repository profile is
      associated with a computer and restore it when the profile is removed.
      (LP: #1607529)
    - Drop the legacy HAService plugin, which is no longer used.
    - Avoid double-decoding package descriptions in build_skeleton_apt, which
      causes an error with Xenial python-apt. (LP: #1655395)
    - Remove dead dbus code and textmessage (confirmed not supported in server
      for ~2 years). (LP: #1657372)
    - Move bzr-builddeb conf file from deprecated location to debian/
      (LP: #1658796)
    - Support for new server error message about there being too many pending
      computers already (LP: #1662530)
    - Add a timestamp to the package reporter result (LP: #1674252)
    - Check if ubuntu-release-upgrader is running before apt-update (LP: #1699179)
    - Implicitly trust file-local sources managed by landscape. On upgrades,
      add the trusted flag to the landscape file-local apt source file if it's
      not there. (LP: #1736576)
    - Use local system tools to change the user's password (LP: #1743558)
  * clean up packaging and getting in sync with the new landscape version:
    - d/rules: drop extra:suggests which is unused since 13.07.1-0ubuntu2
    - Remove antique postinst code. No supported landscape-client version
      installs cronjobs anymore (since a long time).
    - d/landscape-client.docs: the README file is now a markdown file, so
      install that instead.
    - d/landscape-common.postinst: no need to single out
      /var/lib/landscape/.gnupg when fixing ownerships, just do it over
      the entire parent directory.
    - guard user and group removal via an empty .cleanup.* file in post, so we
      only remove the user/group if we were the ones who created them at
      install time.
    - lintian: remove absolute path from update-motd calls in maintainer
      scripts
    - d/rules: drop special handling for dapper, hardy and lucid, which are no
      longer supported.
    - d/rules: make sure we have an "extra:Depends=" in substvars even if it's
      empty
    - d/rules: drop dh_pycentral handling, it's obsolete
  * Dropped (already included in this version):
    - d/p/set-vm-info-to-kvm-for-aws-C5-instances.patch:
  ...