Ubuntu: USN-3047-2: QEMU regression

Description

USN-3047-1 fixed vulnerabilities in QEMU. The patch to fixCVE-2016-5403 caused a regression which resulted in save/restore failures when virtio memory balloon statistics are enabled. This update temporarily reverts the security fix forCVE-2016-5403pending further investigation. We apologize for the inconvenience.

Original advisory details:

Li Qiang discovered that QEMU incorrectly handled 53C9X Fast SCSI controller emulation. A privileged attacker inside the guest could use this issue to cause QEMU to crash, resulting in a denial of service, or possibly execute arbitrary code on the host. In the default installation, when QEMU is used with libvirt, attackers would be isolated by the libvirt AppArmor profile. This issue only applied to Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2016-4439,CVE-2016-4441,CVE-2016-5238,CVE-2016-5338,CVE-2016-6351) Li Qiang and Qinghao Tang discovered that QEMU incorrectly handled the VMWare VGA module. A privileged attacker inside the guest could use this issue to cause QEMU to crash, resulting in a denial of service, or possibly to obtain sensitive host memory. (CVE-2016-4453,CVE-2016-4454) Li Qiang discovered that QEMU incorrectly handled VMWARE PVSCSI paravirtual SCSI bus emulation support. A privileged attacker inside the guest could use this issue to cause QEMU to crash, resulting in a denial of service. This issue only applied to Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2016-4952) Li Qiang discovered that QEMU incorrectly handled MegaRAID SAS 8708EM2 Host Bus Adapter emulation support. A privileged attacker inside the guest could use this issue to cause QEMU to crash, resulting in a denial of service, or possibly to obtain sensitive host memory. This issue only applied to Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2016-5105,CVE-2016-5106, CVE-2016-5107,CVE-2016-5337) It was discovered that QEMU incorrectly handled certain iSCSI asynchronous I/O ioctl calls. An attacker inside the guest could use this issue to cause QEMU to crash, resulting in a denial of service, or possibly execute arbitrary code on the host. In the default installation, when QEMU is used with libvirt, attackers would be isolated by the libvirt AppArmor profile. This issue only applied to Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2016-5126) Zhenhao Hong discovered that QEMU incorrectly handled the Virtio module. A privileged attacker inside the guest could use this issue to cause QEMU to crash, resulting in a denial of service. (CVE-2016-5403)