In the Linux kernel, the following vulnerability has been resolved: hugetlb: only adjust reservation during unmapping if mapcount is 0 Since df7a6d1f6405, __unmap_hugepage_range can adjust reservations. In the case of folio mapped in both a parent and a child, if the parent unmaps the range first, the reservation adjustment will result in an underflow of the reserved count. Once the child unmaps the range, the count is restored.
Change __unmap_hugepage_range() to check the mapcount
before adjusting the reservation.
Attack Parameters
Attack Vector
Local
Requires local access
Attack Complexity
Low
Easy to exploit
Privileges Required
Low
Basic privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
None
No data leak
Integrity
High
Complete data modification
Availability
High
Complete denial of service
CVSS Vector v3.1
References 4
https://git.kernel.org/stable/c/0f001491e5a2ec69aa9d5dd6b799e5742245f9ea
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/5120b1e048d48596ffaec1a8412012a91adba73b
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/a3c65af20cceb7f997847727636b4017326f845d
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/b0b1b9ca80b795ed2223e76dd787db7067121fb9
416baaa9-dc9f-4396-8d5f-8c081fb06d67