Mikołaj Lenczewski

Name of the Vulnerable Software and Affected Versions: Linux kernel (affected versions not specified) Description: The issue arises when a memory region previously registered with userfaultfd as write-protected but without UFFD FEATURE EVENT REMAP is mremap()ed, leading to an inconsistency in flag clearing. This inconsistency causes a mismatch between the vma flags and the pte/pmd flags, resulting in a warning when setting the pte to writable while uffd-wp is still set. The fix involves explicitly clearing the uffd-wp pte/pmd flags on any such mremap() to ensure consistent values with the existing clearing of VM UFFD WP. Recommendations: At the moment, there is no information about a newer version that contains a fix for this vulnerability.