[Openstack-security] [Bug 1851587] Re: HypervisorUnavailable error leaks compute host fqdn to non-admin users

Nick Tait 1851587 at bugs.launchpad.net
Wed Dec 4 18:29:59 UTC 2019


So far I agree with hardening classification. But what I don't yet
understand is why revealing FQDN is a security problem. Pretend I am a
non-admin, and I learn that there is a compute host available at
www.example.com. Wouldn't I need valid access credentials to that host
before viewing/tampering with it?

In the physical world, leaking your home address to an adversary would
be a security problem. How does this transfer into the digital example?
In the case of OpenStack being run as a public cloud, the non-admin user
has to be treated as a potentially untrustworthy person.

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Title:
  HypervisorUnavailable error leaks compute host fqdn to non-admin users

Status in OpenStack Compute (nova):
  New
Status in OpenStack Security Advisory:
  Won't Fix

Bug description:
  Description
  ===========
  When an instance encounters a HypervisorUnavailable error, the non-admin user gets the info of the compute host fqdn in the error message. 

  Steps to reproduce
  ==================
  1. Spin up an instance with non-admin user credentials
  2. To reproduce the error, stop the libvirtd service on the compute host containing instance
  3. Delete the instance
  4. Deletion fails providing HypervisorUnavailable error

  Expected result
  ===============
  Error does not show compute host fqdn to a non-admin user

  Actual result
  =============
  #spin up an instance
  +--------------------------------------+------------+--------+------------+-------------+-------------------------------------+------------------------------+--------------------------------------+-------------+-----------+-------------------+------+------------+
  | ID                                   | Name       | Status | Task State | Power State | Networks                            | Image Name                   | Image ID                             | Flavor Name | Flavor ID | Availability Zone | Host | Properties |
  +--------------------------------------+------------+--------+------------+-------------+-------------------------------------+------------------------------+--------------------------------------+-------------+-----------+-------------------+------+------------+
  | 4f42886d-e1f8-4607-a09d-0dc12a681880 | test-11869 | ACTIVE | None       | Running     | private=192.168.100.158, 10.0.0.243 | cirros-0.4.0-x86_64-disk.img | 5d0bd6a5-7331-4ebe-9328-d126189897e2 |             |           | nova              |      |            |
  +--------------------------------------+------------+--------+------------+-------------+-------------------------------------+------------------------------+--------------------------------------+-------------+-----------+-------------------+------+------------+

  #instance is running on compute-0 node (only admin knows this)
  [heat-admin at compute-0 ~]$ sudo virsh list --all
   Id    Name                           State
  ----------------------------------------------------
   108   instance-00000092              running

  #stop libvirtd service
  [root at compute-0 heat-admin]# systemctl stop tripleo_nova_libvirt.service
  [root at compute-0 heat-admin]# systemctl status tripleo_nova_libvirt.service
  ● tripleo_nova_libvirt.service - nova_libvirt container
     Loaded: loaded (/etc/systemd/system/tripleo_nova_libvirt.service; enabled; vendor preset: disabled)
     Active: inactive (dead) since Wed 2019-11-06 22:48:25 UTC; 5s ago
    Process: 8514 ExecStop=/usr/bin/podman stop -t 10 nova_libvirt (code=exited, status=0/SUCCESS)
   Main PID: 3783

  Nov 06 22:29:48 compute-0 podman[3396]: 2019-11-06 22:29:48.443603571 +0000 UTC m=+1.325620613 container init a3e32121d12929e663b899b57cb7bc87581ddf5bdfb19cf8fee4bace41cb19bb (image=undercloud-0.ctlpla>
  Nov 06 22:29:48 compute-0 podman[3396]: 2019-11-06 22:29:48.475946808 +0000 UTC m=+1.357963869 container start a3e32121d12929e663b899b57cb7bc87581ddf5bdfb19cf8fee4bace41cb19bb (image=undercloud-0.ctlpl>
  Nov 06 22:29:48 compute-0 paunch-start-podman-container[3385]: nova_libvirt
  Nov 06 22:29:48 compute-0 paunch-start-podman-container[3385]: Creating additional drop-in dependency for "nova_libvirt" (a3e32121d12929e663b899b57cb7bc87581ddf5bdfb19cf8fee4bace41cb19bb)
  Nov 06 22:29:49 compute-0 systemd[1]: Started nova_libvirt container.
  Nov 06 22:48:24 compute-0 systemd[1]: Stopping nova_libvirt container...
  Nov 06 22:48:25 compute-0 podman[8514]: 2019-11-06 22:48:25.595405651 +0000 UTC m=+1.063832024 container died a3e32121d12929e663b899b57cb7bc87581ddf5bdfb19cf8fee4bace41cb19bb (image=undercloud-0.ctlpla>
  Nov 06 22:48:25 compute-0 podman[8514]: 2019-11-06 22:48:25.597210594 +0000 UTC m=+1.065636903 container stop a3e32121d12929e663b899b57cb7bc87581ddf5bdfb19cf8fee4bace41cb19bb (image=undercloud-0.ctlpla>
  Nov 06 22:48:25 compute-0 podman[8514]: a3e32121d12929e663b899b57cb7bc87581ddf5bdfb19cf8fee4bace41cb19bb
  Nov 06 22:48:25 compute-0 systemd[1]: Stopped nova_libvirt container.

  #delete the instance, it leaks compute host fqdn to the non-admin user
  (overcloud) [stack at undercloud-0 ~]$ nova delete test-11869
  Request to delete server test-11869 has been accepted.
  (overcloud) [stack at undercloud-0 ~]$ openstack server list --long
  +--------------------------------------+------------+--------+------------+-------------+----------+------------------------------+--------------------------------------+-------------+-----------+-------------------+------+------------+
  | ID                                   | Name       | Status | Task State | Power State | Networks | Image Name                   | Image ID                             | Flavor Name | Flavor ID | Availability Zone | Host | Properties |
  +--------------------------------------+------------+--------+------------+-------------+----------+------------------------------+--------------------------------------+-------------+-----------+-------------------+------+------------+
  | 4f42886d-e1f8-4607-a09d-0dc12a681880 | test-11869 | ERROR  | None       | Running     |          | cirros-0.4.0-x86_64-disk.img | 5d0bd6a5-7331-4ebe-9328-d126189897e2 |             |           | nova              |      |            |
  +--------------------------------------+------------+--------+------------+-------------+----------+------------------------------+--------------------------------------+-------------+-----------+-------------------+------+------------+
  (overcloud) [stack at undercloud-0 ~]$ openstack server show test-11869 <---debug output attached in logs
  +-----------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
  | Field                       | Value                                                                                                                                 |
  +-----------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
  | OS-DCF:diskConfig           | MANUAL                                                                                                                                |
  | OS-EXT-AZ:availability_zone | nova                                                                                                                                  |
  | OS-EXT-STS:power_state      | Running                                                                                                                               |
  | OS-EXT-STS:task_state       | None                                                                                                                                  |
  | OS-EXT-STS:vm_state         | error                                                                                                                                 |
  | OS-SRV-USG:launched_at      | 2019-11-06T22:13:08.000000                                                                                                            |
  | OS-SRV-USG:terminated_at    | None                                                                                                                                  |
  | accessIPv4                  |                                                                                                                                       |
  | accessIPv6                  |                                                                                                                                       |
  | addresses                   |                                                                                                                                       |
  | config_drive                |                                                                                                                                       |
  | created                     | 2019-11-06T22:12:57Z                                                                                                                  |
  | description                 | None                                                                                                                                  |
  | fault                       | {'code': 500, 'created': '2019-11-06T23:01:45Z', 'message': 'Connection to the hypervisor is broken on host: compute-0.redhat.local'} |
  | flavor                      | disk='1', ephemeral='0', , original_name='m1.tiny', ram='512', swap='0', vcpus='1'                                                    |
  | hostId                      | c7e6bf58b57f435659bb0aa9637c7f830f776ec202a0d6e430ee3168                                                                              |
  | id                          | 4f42886d-e1f8-4607-a09d-0dc12a681880                                                                                                  |
  | image                       | cirros-0.4.0-x86_64-disk.img (5d0bd6a5-7331-4ebe-9328-d126189897e2)                                                                   |
  | key_name                    | None                                                                                                                                  |
  | locked                      | False                                                                                                                                 |
  | locked_reason               | None                                                                                                                                  |
  | name                        | test-11869                                                                                                                            |
  | project_id                  | 6e39619e17a9478580c93120e1cb16bc                                                                                                      |
  | properties                  |                                                                                                                                       |
  | server_groups               | []                                                                                                                                    |
  | status                      | ERROR                                                                                                                                 |
  | tags                        | []                                                                                                                                    |
  | trusted_image_certificates  | None                                                                                                                                  |
  | updated                     | 2019-11-06T23:01:45Z                                                                                                                  |
  | user_id                     | 3cd6a8cb88eb49d3a84f9e67d89df598                                                                                                      |
  | volumes_attached            |                                                                                                                                       |
  +-----------------------------+---------------------------------------------------------------------------------------------------------------------------------------+

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