Linux Kernel Memory Corruption Vulnerability in mshv_region_pin Error Handling

A vulnerability in the Linux kernel's error handling for the 'mshv_region_pin' function can lead to memory corruption. The issue arises because 'pin_user_pages_fast()' may return a short pin count, indicating that not all requested pages were pinned, yet this is incorrectly treated as a success. Consequently, partially pinned regions can be used, causing memory corruption. Additionally, if an error occurs mid-loop, the function fails to properly account for already pinned pages before invalidating the region, leading to a page reference leak. This vulnerability affects the Linux kernel stable tree.

Impact

Improper error handling in the 'mshv_region_pin' function can cause memory corruption and a page reference leak.

Remediation

Users can apply the patch available in the Linux kernel stable tree to address this vulnerability.