[Openstack-security] [Bug 1501808] Re: Enabling soft-deletes opens a DOS on compute hosts
Is anyone working on this?
Can we change the code not to release quota until the instance is reclaimed?
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Enabling soft-deletes opens a DOS on compute hosts
Status in OpenStack Compute (nova):
Status in OpenStack Security Advisory:
If the user sets reclaim_instance_interval to anything other than 0,
then when a user requests an instance delete, it will instead be soft
deleted. Soft delete explicitly releases the user's quota, but does
not release the instance's resources until period task
_reclaim_queued_deletes runs with a period of
A malicious authenticated user can repeatedly create and delete
instances without limit, which will consume resources on the host
without consuming their quota. If done quickly enough, this will
exhaust host resources.
I'm not entirely sure what to suggest in remediation, as this seems to
be a deliberate design. The most obvious fix would be to not release
quota until the instance is reaped, but that would be a significant
change in behaviour.
This is very similar to https://bugs.launchpad.net/bugs/cve/2015-3280
, except that we do it deliberately.
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