Уязвимость функции cpia2_remap_buffer ядра операционной системы Linux, позволяющая нарушителю получить доступ на чтение и запись на физических страницах ядра и повысить свои привилегии

A flaw was found in the way Linux kernel KVM hypervisor before 4.18 emulated instructions such as sgdt/sidt/fxsave/fxrstor. It did not check current privilege(CPL) level while emulating unprivileged instructions. An unprivileged guest user/process could use this flaw to potentially escalate privileges inside guest.

The Linux kernel through 5.3.13 has a start_offset+size Integer Overflow in cpia2_remap_buffer in drivers/media/usb/cpia2/cpia2_core.c because cpia2 has its own mmap implementation. This allows local users (with /dev/video0 access) to obtain read and write permissions on kernel physical pages, which can possibly result in a privilege escalation.