CVE-2021-47008

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. CVE-2021-47008
In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Make sure GHCB is mapped before updating Access to the GHCB is mainly in the VMGEXIT path and it is known that the GHCB will be mapped. But there are two paths where it is possible the GHCB might not be mapped. The sev_vcpu_deliver_sipi_vector() routine will update the GHCB to inform the caller of the AP Reset Hold NAE event that a SIPI has been delivered. However, if a SIPI is performed without a corresponding AP Reset Hold, then the GHCB might not be mapped (depending on the previous VMEXIT), which will result in a NULL pointer dereference. The svm_complete_emulated_msr() routine will update the GHCB to inform the caller of a RDMSR/WRMSR operation about any errors. While it is likely that the GHCB will be mapped in this situation, add a safe guard in this path to be certain a NULL pointer dereference is not encountered.

5.5 /10

CVSS v3 : MEDIUM

V3 Legend

Vector :

Exploitability : 1.8 / Impact : 3.6

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References
Link Resource
https://git.kernel.org/stable/c/a3ba26ecfb569f4aa3f867e80c02aa65f20aadad Patch
https://git.kernel.org/stable/c/fb9e14f4f8217a0980f8da2c8ff70dee058cbe47 Patch
https://git.kernel.org/stable/c/fd722a57fe0b80133dacae4e1c852ee4212f9b2e Patch
https://git.kernel.org/stable/c/a3ba26ecfb569f4aa3f867e80c02aa65f20aadad Patch
https://git.kernel.org/stable/c/fb9e14f4f8217a0980f8da2c8ff70dee058cbe47 Patch
https://git.kernel.org/stable/c/fd722a57fe0b80133dacae4e1c852ee4212f9b2e Patch
Configurations

Configuration 1 (hide)

OR cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
History

09 Dec 2024, 18:24

Type Values Removed Values Added
First Time Linux linux Kernel
Linux
CVSS v2 : unknown
v3 : unknown 		v2 : unknown
v3 : 5.5
References () https://git.kernel.org/stable/c/a3ba26ecfb569f4aa3f867e80c02aa65f20aadad - () https://git.kernel.org/stable/c/a3ba26ecfb569f4aa3f867e80c02aa65f20aadad - Patch
References () https://git.kernel.org/stable/c/fb9e14f4f8217a0980f8da2c8ff70dee058cbe47 - () https://git.kernel.org/stable/c/fb9e14f4f8217a0980f8da2c8ff70dee058cbe47 - Patch
References () https://git.kernel.org/stable/c/fd722a57fe0b80133dacae4e1c852ee4212f9b2e - () https://git.kernel.org/stable/c/fd722a57fe0b80133dacae4e1c852ee4212f9b2e - Patch
CWE CWE-476
CPE cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

21 Nov 2024, 06:35

Type Values Removed Values Added
Summary
  • (es) En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: KVM: SVM: asegúrese de que GHCB esté mapeado antes de actualizar. El acceso al GHCB se encuentra principalmente en la ruta VMGEXIT y se sabe que el GHCB será mapeado. Pero hay dos caminos en los que es posible que el GHCB no esté mapeado. La rutina sev_vcpu_deliver_sipi_vector() actualizará el GHCB para informar a la persona que llama del evento AP Reset Hold NAE que se ha entregado un SIPI. Sin embargo, si se realiza una SIPI sin una retención de reinicio de AP correspondiente, es posible que el GHCB no se asigne (dependiendo del VMEXIT anterior), lo que resultará en una desreferencia del puntero NULL. La rutina svm_complete_emulated_msr() actualizará el GHCB para informar a la persona que llama de una operación RDMSR/WRMSR sobre cualquier error. Si bien es probable que el GHCB se asigne en esta situación, agregue una protección en esta ruta para asegurarse de que no se encuentre una desreferencia de puntero NULL.
References () https://git.kernel.org/stable/c/a3ba26ecfb569f4aa3f867e80c02aa65f20aadad - () https://git.kernel.org/stable/c/a3ba26ecfb569f4aa3f867e80c02aa65f20aadad -
References () https://git.kernel.org/stable/c/fb9e14f4f8217a0980f8da2c8ff70dee058cbe47 - () https://git.kernel.org/stable/c/fb9e14f4f8217a0980f8da2c8ff70dee058cbe47 -
References () https://git.kernel.org/stable/c/fd722a57fe0b80133dacae4e1c852ee4212f9b2e - () https://git.kernel.org/stable/c/fd722a57fe0b80133dacae4e1c852ee4212f9b2e -

28 Feb 2024, 09:15

Type Values Removed Values Added
New CVE
Information

Published : 2024-02-28 09:15

Updated : 2024-12-09 18:24

NVD link : CVE-2021-47008

Mitre link : CVE-2021-47008

CVE.ORG link : CVE-2021-47008

JSON object : View

Products Affected

linux

  • linux_kernel
CWE
CWE-476

NULL Pointer Dereference