Xen lack of preemption in evtchn_reset() / evtchn_destroy() DoS (XSA-344)

A denial of service DoS vulnerability exists in Xen servers in FIFO event channel modules evtchnreset / evtchndestroy due to a lack of preemption. An authenticated, local attacker can mount a Denial of Service DoS attack affecting the entire system. Note that Nessus has not tested for this issue...

Fedora 31 : xen (2020-d46fe34349)

x86 pv: Crash when handling guest access to MSRMISCENABLE XSA-333, CVE-2020-25602 1881619 Missing unlock in XENMEMacquireresource error path XSA-334, CVE-2020-25598 1881616 race when migrating timers between x86 HVM vCPU-s XSA-336, CVE-2020-25604 1881618 PCI passthrough code reading back hardware...

Denial Of Service (DoS)

xen is vulnerable to denial of service DoS. There is a lack of preemption in evtchnreset / evtchndestroy. In particular, the FIFO event channel model allows guests to have a large number of event channels active at a time. Closing all of these when resetting all event channels or when cleaning up...

CVE-2020-25601

An issue was discovered in Xen through 4.14.x. There is a lack of preemption in evtchnreset / evtchndestroy. In particular, the FIFO event channel model allows guests to have a large number of event channels active at a time. Closing all of these when resetting all event channels or when cleaning...