CVE-2021-47008
Assigner: Linux
Published: 2024-02-28T08:13:27.786Z
State: PUBLISHED
descriptions: value: 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.
affected: product: Linux
vendor: Linux
defaultStatus: unaffected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
versions: version: 647daca25d24
lessThan: fb9e14f4f821
status: affected
versionType: git
version: 647daca25d24
lessThan: fd722a57fe0b
status: affected
versionType: git
version: 647daca25d24
lessThan: a3ba26ecfb56
status: affected
versionType: git
product: Linux
vendor: Linux
defaultStatus: affected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
versions: version: 5.11
status: affected
version: 0
lessThan: 5.11
status: unaffected
versionType: custom
version: 5.11.22
lessThanOrEqual: 5.11.*
status: unaffected
versionType: custom
version: 5.12.5
lessThanOrEqual: 5.12.*
status: unaffected
versionType: custom
version: 5.13
lessThanOrEqual: *
status: unaffected
versionType: original_commit_for_fix
title: KVM: SVM: Make sure GHCB is mapped before updating
x_generator: engine: bippy-c298863b1525