Comment 19 for bug 1732976

Revision history for this message
Matt Riedemann (mriedem) wrote : Re: Potential DoS by rebuilding the same instance with a new image multiple times

Here is the stable/pike fix for the new DoS issue:

https://review.openstack.org/#/c/523214/

As for the description, I'd make the following changes:

1. Change the title to: "Nova FilterScheduler doubles resource allocations during rebuild with new image"

2. The last sentence is a bit confusing:

> This regression was introduced with the fix for OSSA-2017-005 (CVE-2017-16239), so only Nova stable/pike or later deployments with that fix applied and relying on the default FilterScheduler are affected.

The fix for CVE-2017-16239 went further than stable/pike. I think the thing to point out is that this new CVE only affects deployments running stable/pike or later, including on all of their nova-compute services and the scheduler. Before Pike the FilterScheduler in the nova-scheduler service won't create allocations in Placement, and before Pike the ResourceTracker in the nova-compute service will automatically adjust allocations in Placement in a periodic task.

So maybe we should say, "This regression was introduced with the fix for OSSA-2017-005 (CVE-2017-16239), however, only Nova stable/pike or later deployments with that fix applied and relying on the default FilterScheduler are affected."