A flaw was found in the libvirt nwfilter driver. The virNWFilterObjListNumOfNWFilters method failed to acquire the driver->nwfilters mutex before iterating over virNWFilterObj instances. There was no protection to stop another thread from concurrently modifying the driver->nwfilters object. This flaw allows a malicious, unprivileged user to exploit this issue via libvirts API virConnectNumOfNWFilters to crash the network filter management daemon (libvirtd/virtnwfilterd).
The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Libvirt | Redhat | * | 1.1.1 (including) |
Locking is a type of synchronization behavior that ensures that multiple independently-operating processes or threads do not interfere with each other when accessing the same resource. All processes/threads are expected to follow the same steps for locking. If these steps are not followed precisely - or if no locking is done at all - then another process/thread could modify the shared resource in a way that is not visible or predictable to the original process. This can lead to data or memory corruption, denial of service, etc.