// For flags

CVE-2021-47450

KVM: arm64: Fix host stage-2 PGD refcount

Severity Score

"-"
*CVSS v-

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

Track
*SSVC
Descriptions

In the Linux kernel, the following vulnerability has been resolved:

KVM: arm64: Fix host stage-2 PGD refcount

The KVM page-table library refcounts the pages of concatenated stage-2
PGDs individually. However, when running KVM in protected mode, the
host's stage-2 PGD is currently managed by EL2 as a single high-order
compound page, which can cause the refcount of the tail pages to reach 0
when they shouldn't, hence corrupting the page-table.

Fix this by introducing a new hyp_split_page() helper in the EL2 page
allocator (matching the kernel's split_page() function), and make use of
it from host_s2_zalloc_pages_exact().

En el kernel de Linux, se resolvió la siguiente vulnerabilidad: KVM: arm64: corrige el recuento de PGD de etapa 2 del host La librería de tablas de páginas de KVM vuelve a contar las páginas de los PGD de etapa 2 concatenados individualmente. Sin embargo, cuando se ejecuta KVM en modo protegido, EL2 administra actualmente el PGD de etapa 2 del host como una única página compuesta de alto orden, lo que puede causar que el recuento de las páginas finales llegue a 0 cuando no debería, corrompiendo así el tabla de páginas. Solucione este problema introduciendo un nuevo asistente hyp_split_page() en el asignador de páginas EL2 (que coincida con la función split_page() del kernel) y utilícelo desde host_s2_zalloc_pages_exact().

*Credits: N/A
CVSS Scores
Attack Vector
-
Attack Complexity
-
Privileges Required
-
User Interaction
-
Scope
-
Confidentiality
-
Integrity
-
Availability
-
* Common Vulnerability Scoring System
SSVC
  • Decision:Track
Exploitation
None
Automatable
No
Tech. Impact
Partial
* Organization's Worst-case Scenario
Timeline
  • 2024-05-21 CVE Reserved
  • 2024-05-22 CVE Published
  • 2024-05-22 EPSS Updated
  • 2024-12-19 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Linux
Search vendor "Linux"
 Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
 >= 5.13 < 5.14.15
Search vendor "Linux" for product "Linux Kernel" and version " >= 5.13 < 5.14.15"
en
Affected
Linux
Search vendor "Linux"
 Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
 >= 5.13 < 5.15
Search vendor "Linux" for product "Linux Kernel" and version " >= 5.13 < 5.15"
en
Affected