5.5

CVE-2021-47008

KVM: SVM: Make sure GHCB is mapped before updating

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.
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Linux ≫ Linux Kernel Version >= 5.11 < 5.11.22
Linux ≫ Linux Kernel Version >= 5.12 < 5.12.5
Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.24% 0.143
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
NIST 5.5 1.8 3.6
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CWE-476 NULL Pointer Dereference

The product dereferences a pointer that it expects to be valid but is NULL.

https://git.kernel.org/stable/c/a3ba26ecfb569f4aa3f867e80c02aa65f20aadad
Patch
https://git.kernel.org/stable/c/fb9e14f4f8217a0980f8da2c8ff70dee058cbe47
Patch
https://git.kernel.org/stable/c/fd722a57fe0b80133dacae4e1c852ee4212f9b2e
Patch