CVE-2015-5307

Published: 10 November 2015

The KVM subsystem in the Linux kernel through 4.2.6, and Xen 4.3.x through 4.6.x, allows guest OS users to cause a denial of service (host OS panic or hang) by triggering many #AC (aka Alignment Check) exceptions, related to svm.c and vmx.c.

From the Ubuntu Security Team

Ben Serebrin discovered that the KVM hypervisor implementation in the Linux kernel did not properly catch Alignment Check exceptions. An attacker in a guest virtual machine could use this to cause a denial of service (system crash) in the host OS.

Notes

android kernels (flo, goldfish, grouper, maguro, mako and manta) are
not supported on the Ubuntu Touch 14.10 and earlier preview kernels
linux-lts-saucy no longer receives official support
linux-lts-quantal no longer receives official support

affects x86 kernels only
fixed in upstream 54a20552e1eae07aa240fa370a0293e006b5faed ;
however, it hadn't made it to linus' tree before we published kernels
for it, so manually recording everything.

Status

References

• https://ubuntu.com/security/notices/USN-2806-1
• https://ubuntu.com/security/notices/USN-2805-1
• https://ubuntu.com/security/notices/USN-2802-1
• https://ubuntu.com/security/notices/USN-2801-1
• https://ubuntu.com/security/notices/USN-2804-1
• https://ubuntu.com/security/notices/USN-2800-1
• https://ubuntu.com/security/notices/USN-2803-1
• https://ubuntu.com/security/notices/USN-2807-1
• https://www.cve.org/CVERecord?id=CVE-2015-5307
• NVD
• Launchpad
• Debian

Bugs

• https://launchpad.net/bugs/1513540