In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: nv: Respect read-only PFN when mapping L1 VNCR
KVM currently maps the L1 VNCR into the host stage-1 by relying entirely
on the permissions of the guest stage-1. At the same time, it is
entirely possible that the backing PFN is read-only (e.g. RO memslot),
meaning that the L1 VNCR should use at most a read-only mapping.
Cache the writability of the PFN in the VNCR TLB and use it to constrain
the resulting fixmap permissions. Promote VNCR permission faults to an
SEA in the case where the guest attempts to write to a read-only
endpoint. Conveniently, this also plugs a page leak found by Sashiko [*]
resulting from the early return for a read-only PFN.
Attack Parameters
Attack Vector
Local
Requires local access
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No 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 3
https://git.kernel.org/stable/c/2684e02bac41c5220f6c1ab2bdcc957b71812977
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/5c50db5bcbb9073cb2fd97be51b962de92f429e9
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/d35defbdfcb15296ebe28968ad7452c1a8c11cea
416baaa9-dc9f-4396-8d5f-8c081fb06d67