[3.5.y.z extended stable] Patch "KVM: VMX: fix use after free of vmx->loaded_vmcs" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    KVM: VMX: fix use after free of vmx->loaded_vmcs

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 46c2c6cbee84166598fa736b39872d6ad434a0a9 Mon Sep 17 00:00:00 2001
From: Marcelo Tosatti <mtosatti at redhat.com>
Date: Fri, 3 Jan 2014 17:00:51 -0200
Subject: KVM: VMX: fix use after free of vmx->loaded_vmcs

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 eed06fc..732cf6c 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6324,8 +6324,8 @@ 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