CVE Published: 03/05/2024 |
CVE Updated: 04/11/2024 |
CVE Year: 2022 Source: Linux |
Vendor: Linux |
Product: Linux Status : PUBLISHED
CVE-2022-48700 Description
In the Linux kernel, the following vulnerability has been resolved:
vfio/type1: Unpin zero pages
There\'s currently a reference count leak on the zero page. We increment
the reference via pin_user_pages_remote(), but the page is later handled
as an invalid/reserved page, therefore it\'s not accounted against the
user and not unpinned by our put_pfn().
Introducing special zero page handling in put_pfn() would resolve the
leak, but without accounting of the zero page, a single user could
still create enough mappings to generate a reference count overflow.
The zero page is always resident, so for our purposes there\'s no reason
to keep it pinned. Therefore, add a loop to walk pages returned from
pin_user_pages_remote() and unpin any zero pages.