From: Maxim Levitsky mlevitsk@redhat.com
commit 16ae56d7e0528559bf8dc9070e3bfd8ba3de80df upstream.
Make sure that KVM uses vmcb01 before freeing nested state, and warn if that is not the case.
This is a minimal fix for CVE-2022-3344 making the kernel print a warning instead of a kernel panic.
Cc: stable@vger.kernel.org Signed-off-by: Maxim Levitsky mlevitsk@redhat.com Message-Id: 20221103141351.50662-3-mlevitsk@redhat.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kvm/svm/nested.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -1143,6 +1143,9 @@ void svm_free_nested(struct vcpu_svm *sv if (!svm->nested.initialized) return;
+ if (WARN_ON_ONCE(svm->vmcb != svm->vmcb01.ptr)) + svm_switch_vmcb(svm, &svm->vmcb01); + svm_vcpu_free_msrpm(svm->nested.msrpm); svm->nested.msrpm = NULL;