[PATCH 3.11 088/131] KVM: VMX: fix use after free of vmx->loaded_vmcs

[Luis Henriques]

3.11.10.6 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Marcelo Tosatti <mtosatti at redhat.com>

commit 26a865f4aa8e66a6d94958de7656f7f1b03c6c56 upstream.

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

Reviewed-by: Jan Kiszka <jan.kiszka at siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti at redhat.com>
Cc: Josh Boyer <jwboyer at fedoraproject.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 arch/x86/kvm/vmx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 064d0be..aef3d79 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -7142,8 +7142,8 @@ 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);
-- 
1.9.0