xen/gnttab: fix gnttabendforeign_access() without page specified
This is an automated ID intended to aid in discovery of potential security vulnerabilities. The actual impact and attack plausibility have not yet been proven. This ID is fixed in Linux Kernel version v4.14.271 by commit 94b8ccbcc063325d23daa1cea89ef799c8c673e9. For more details please see the references link.