CVE-2019-9213

En el kernel de Linux, en versiones anteriores a la 4.20.14, expand_downwards en mm/mmap.c carece de una comprobación para la dirección mínima de mmap, lo que facilita que los atacantes exploten desreferencias de puntero NULL en el kernel en plataformas que no son SMAP. Esto esto está relacionado con una comprobación de capacidades para la tarea equivocada.

A flaw was found in mmap in the Linux kernel allowing the process to map a null page. This allows attackers to abuse this mechanism to turn null pointer dereferences into workable exploits.

M. Vefa Bicakci and Andy Lutomirski discovered that the kernel did not properly set up all arguments to an error handler callback used when running as a paravirtualized guest. An unprivileged attacker in a paravirtualized guest VM could use this to cause a denial of service. It was discovered that the KVM implementation in the Linux kernel on ARM 64bit processors did not properly handle some ioctls. An attacker with the privilege to create KVM-based virtual machines could use this to cause a denial of service or execute arbitrary code in the host. Various other issues were also addressed.