The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

Possible dependencies:

16ae56d7e052 ("KVM: x86: nSVM: harden svm_free_nested against freeing vmcb02 while still in use")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 16ae56d7e0528559bf8dc9070e3bfd8ba3de80df Mon Sep 17 00:00:00 2001 From: Maxim Levitsky mlevitsk@redhat.com Date: Thu, 3 Nov 2022 16:13:44 +0200 Subject: [PATCH] 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

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 4c620999d230..b02a3a1792f1 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -1125,6 +1125,9 @@ 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;