CVE-2017-2583

La implementación de load_segment_descriptor en arc/x86/kvm/emulate.c en el kernel de Linux en versiones anteriores a 4.9.5 emula indebidamente una instrucción "MOV SS, NULL selector", lo que permite a usuarios del SO invitado provocar una denegación de servicio (caída del SO invitado) u obteniendo privilegios de SO invitado a través de una aplicación manipulada.

Linux kernel built with the Kernel-based Virtual Machine (CONFIG_KVM) support was vulnerable to an incorrect segment selector(SS) value error. The error could occur while loading values into the SS register in long mode. A user or process inside a guest could use this flaw to crash the guest, resulting in DoS or potentially escalate their privileges inside the guest.

The kernel-rt packages provide the Real Time Linux Kernel, which enables fine-tuning for systems with extremely high determinism requirements. Security Fix: A flaw was found in the way memory was being allocated on the stack for user space binaries. If heap and stack memory regions were adjacent to each other, an attacker could use this flaw to jump over the stack guard gap, cause controlled memory corruption on process stack or the adjacent memory region, and thus increase their privileges on the system. This is a kernel-side mitigation which increases the stack guard gap size from one page to 1 MiB to make successful exploitation of this issue more difficult.