CVE-2023-53171

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> vfio/type1: prevent underflow of locked_vm via exec()<br /> <br /> When a vfio container is preserved across exec, the task does not change,<br /> but it gets a new mm with locked_vm=0, and loses the count from existing<br /> dma mappings. If the user later unmaps a dma mapping, locked_vm underflows<br /> to a large unsigned value, and a subsequent dma map request fails with<br /> ENOMEM in __account_locked_vm.<br /> <br /> To avoid underflow, grab and save the mm at the time a dma is mapped.<br /> Use that mm when adjusting locked_vm, rather than re-acquiring the saved<br /> task&amp;#39;s mm, which may have changed. If the saved mm is dead, do nothing.<br /> <br /> locked_vm is incremented for existing mappings in a subsequent patch.