An updated virtio-win package that fixes one security issue and two bugs isnow available for Red Hat Enterprise Linux 7 Supplementary.Red Hat Product Security has rated this update as having Important securityimpact. A Common Vulnerability Scoring System (CVSS) base score, whichgives a detailed severity rating, is available from the CVE link in theReferences section.

The virtio-win package provides paravirtualized network drivers for mostMicrosoft Windows operating systems. Paravirtualized drivers arevirtualization-aware drivers used by fully virtualized guests running onRed Hat Enterprise Linux. Fully virtualized guests using theparavirtualized drivers gain significantly better I/O performance thanfully virtualized guests running without the drivers.It was found that the Windows Virtio NIC driver did not sufficientlysanitize the length of the incoming IP packets, as demonstrated by a packetwith IP options present but the overall packet length not being adjusted toreflect the length of those options. A remote attacker able to send aspecially crafted IP packet to the guest could use this flaw to crash thatguest. (CVE-2015-3215)Red Hat would like to thank Google Project Zero for reporting this issue.This update also fixes the following bugs:* When creating a Windows guest using virtio drivers and direct LogicalUnit Number (LUN) access with more than 4 SCSI disks under onevirtio-scsi-pci controller, the guest terminated unexpectedly with a stoperror, also known as the blue screen of death. This update increases themaximum amount of LUNs per a single virtio-scsi-pci controller has beenincreased to 254, which prevents the described crash from occurring.(BZ#1207546)* The license.txt file in the virtio-win build has been updated to includethe correct year number in the copyright information section. (BZ#1183427)All virtio-win users are advised to upgrade to this updated package, whichcontains backported patches to correct these issues.
Before applying this update, make sure all previously released erratarelevant to your system have been applied.For details on how to apply this update, refer to:
1227634 – CVE-2015-3215 virtio-win: netkvm: malformed packet can cause BSOD

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