OSSN/OSSN-0016

Summary
A configuration error can prevent the secure erase of volumes in Cinder on Grizzly, potentially allowing a user to recover another user’s data.

Affected Services / Software
Cinder, Grizzly

Discussion
In Cinder on Grizzly, a configurable method to perform a secure erase of volumes was added. In the event of a misconfiguration no secure erase will be performed.

The default code path in Cinder’s clear_volume method, which is taken in the event of a configuration error, results in no wiping of the volume - even in the event that the user had flagged the volume for wiping.

This is the same behaviour as if the volume_clear = ‘none’ option was selected. This could let an attacker recover data from a volume that was intended to be securely erased. Examples of possible incorrect configuration options include values that would appear to result in a secure erase, for example “volume_clear = true” or “volume_clear = yes”.

In the event of a misconfiguration resulting in this issue, the message “Error unrecognized volume_clear option” should be present in log files.

Recommended Actions
- Create and clear a volume (cinder create --display_name erasetest 10; cinder delete erasetest) - Review log files for the above error message (grep “Error unrecognized volume_clear option” ) - Review configuration files to ensure that the valid options ‘zero’ or ‘shred’ are specified.

Contacts / References

 * Author: Doug Chivers, HP
 * This OSSN : https://wiki.openstack.org/wiki/OSSN/OSSN-0016
 * Original LaunchPad Bug : https://bugs.launchpad.net/cinder/+bug/1322766
 * OpenStack Security ML : openstack-security@lists.openstack.org
 * OpenStack Security Group : https://launchpad.net/~openstack-ossg