Kernel Live Patch Security Notice LSN-0065-1

Andrew Honig reported a flaw in the way KVM (Kernel-based Virtual Machine) emulated the IOAPIC. A privileged guest user could exploit this flaw to read host memory or cause a denial of service (crash the host). It was discovered that the KVM implementation in the Linux kernel, when paravirtual TLB flushes are enabled in guests, the hypervisor in some situations could miss deferred TLB flushes or otherwise mishandle them. An attacker in a guest VM could use this to expose sensitive information (read memory from another guest VM). Al Viro discovered that the vfs layer in the Linux kernel contained a use- after-free vulnerability. A local attacker could use this to cause a denial of service (system crash) or possibly expose sensitive information (kernel memory).