From: Maxim Levitsky <mlevitsk@redhat.com>
To: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
Borislav Petkov <bp@alien8.de>, Ingo Molnar <mingo@redhat.com>,
Sean Christopherson <seanjc@google.com>,
x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Maxim Levitsky <mlevitsk@redhat.com>,
stable@vger.kernel.org
Subject: [PATCH 2/4] KVM: x86: nSVM: harden svm_free_nested against freeing vmcb02 while still in use
Date: Thu, 20 Oct 2022 12:30:53 +0300 [thread overview]
Message-ID: <20221020093055.224317-3-mlevitsk@redhat.com> (raw)
In-Reply-To: <20221020093055.224317-1-mlevitsk@redhat.com>
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 4c620999d230a5..b02a3a1792f194 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;
--
2.26.3
next prev parent reply other threads:[~2022-10-20 9:31 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-20 9:30 [PATCH 0/4] nSVM: fix L0 crash if L2 has shutdown condtion which L1 doesn't intercept Maxim Levitsky
2022-10-20 9:30 ` [PATCH 1/4] KVM: x86: nSVM: leave nested mode on vCPU free Maxim Levitsky
2022-10-20 9:30 ` Maxim Levitsky [this message]
2022-10-20 9:30 ` [PATCH 3/4] KVM: x86: add kvm_leave_nested Maxim Levitsky
2022-10-20 9:30 ` [PATCH 4/4] KVM: x86: forcibly leave nested mode on vCPU reset Maxim Levitsky
2022-10-20 15:33 ` Sean Christopherson
2022-10-25 13:37 ` Maxim Levitsky
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