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Maxim Levitskybonzini
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KVM: x86: nSVM: harden svm_free_nested against freeing vmcb02 while still in use
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>
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arch/x86/kvm/svm/nested.c

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@@ -1125,6 +1125,9 @@ void svm_free_nested(struct vcpu_svm *svm)
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if (!svm->nested.initialized)
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return;
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if (WARN_ON_ONCE(svm->vmcb != svm->vmcb01.ptr))
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svm_switch_vmcb(svm, &svm->vmcb01);
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svm_vcpu_free_msrpm(svm->nested.msrpm);
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svm->nested.msrpm = NULL;
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