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@xxxxxxxxxxxxxxx>.
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@xxxxxxxxxx>
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@xxxxxxxxxxxxxxx
Signed-off-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
Message-Id: <20221103141351.50662-3-mlevitsk@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
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;
