Messages in this thread Patch in this message | | | From | Maxim Levitsky <> | Subject | [PATCH v2 2/9] KVM: x86: nSVM: harden svm_free_nested against freeing vmcb02 while still in use | Date | Thu, 3 Nov 2022 16:13:44 +0200 |
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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> --- arch/x86/kvm/svm/nested.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index b258d6988f5dde..b74da40c1fc40c 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -1126,6 +1126,9 @@ void svm_free_nested(struct vcpu_svm *svm) 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; -- 2.34.3
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