kernel KVM before versions kernel 4.16, kernel 4.16-rc7, kernel 4.17-rc1,
kernel 4.17-rc2 and kernel 4.17-rc3 is vulnerable to a flaw in the way the
Linux kernel’s KVM hypervisor handled exceptions delivered after a stack
switch operation via Mov SS or Pop SS instructions. During the stack switch
operation, the processor did not deliver interrupts and exceptions, rather
they are delivered once the first instruction after the stack switch is
executed. An unprivileged KVM guest user could use this flaw to crash the
guest or, potentially, escalate their privileges in the guest.
Notes
Author |
Note |
tyhicks |
Thanks to Andy Lutomirski for help in Linux kernel research and test case |