Fix use after free crash in KVM (rhbz 1047892)

1 files changed, 88 insertions, 0 deletions

diff --git a/KVM-VMX-fix-use-after-free-of-vmx-loaded_vmcs.patch b/KVM-VMX-fix-use-after-free-of-vmx-loaded_vmcs.patch
new file mode 100644
index 000000000..5867231c9
--- /dev/null
+++ b/KVM-VMX-fix-use-after-free-of-vmx-loaded_vmcs.patch
@@ -0,0 +1,88 @@
+Bugzilla: 1047892
+Upstream-status: Submitted for 3.14
+
+Path: news.gmane.org!not-for-mail
+From: Marcelo Tosatti <mtosatti@redhat.com>
+Newsgroups: gmane.comp.emulators.kvm.devel
+Subject: KVM: VMX: fix use after free of vmx->loaded_vmcs
+Date: Fri, 3 Jan 2014 17:00:51 -0200
+Lines: 31
+Approved: news@gmane.org
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+Cc: Jan Kiszka <jan.kiszka@web.de>, Paolo Bonzini <pbonzini@redhat.com>
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+Archived-At: <http://permalink.gmane.org/gmane.comp.emulators.kvm.devel/117837>
+
+
+After free_loaded_vmcs executes, the "loaded_vmcs" structure 
+is kfreed, and now vmx->loaded_vmcs points to a kfreed area. 
+Subsequent free_loaded_vmcs then attempts to manipulate 
+vmx->loaded_vmcs.
+
+Switch the order to avoid the problem.
+
+https://bugzilla.redhat.com/show_bug.cgi?id=1047892
+
+Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
+
+diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
+index da7837e..2efa33f0 100644
+--- a/arch/x86/kvm/vmx.c
++++ b/arch/x86/kvm/vmx.c
+@@ -7332,8 +7332,8 @@ static void vmx_free_vcpu(struct kvm_vcpu *vcpu)
+ 	struct vcpu_vmx *vmx = to_vmx(vcpu);
+ 
+ 	free_vpid(vmx);
+-	free_nested(vmx);
+ 	free_loaded_vmcs(vmx->loaded_vmcs);
++	free_nested(vmx);
+ 	kfree(vmx->guest_msrs);
+ 	kvm_vcpu_uninit(vcpu);
+ 	kmem_cache_free(kvm_vcpu_cache, vmx);
+--
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