CVE-2022-49989

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> xen/privcmd: fix error exit of privcmd_ioctl_dm_op()<br /> <br /> The error exit of privcmd_ioctl_dm_op() is calling unlock_pages()<br /> potentially with pages being NULL, leading to a NULL dereference.<br /> <br /> Additionally lock_pages() doesn&amp;#39;t check for pin_user_pages_fast()<br /> having been completely successful, resulting in potentially not<br /> locking all pages into memory. This could result in sporadic failures<br /> when using the related memory in user mode.<br /> <br /> Fix all of that by calling unlock_pages() always with the real number<br /> of pinned pages, which will be zero in case pages being NULL, and by<br /> checking the number of pages pinned by pin_user_pages_fast() matching<br /> the expected number of pages.