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Commit ecec7688 authored by Peter Shier's avatar Peter Shier Committed by Paolo Bonzini
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KVM: nVMX: unconditionally cancel preemption timer in free_nested (CVE-2019-7221) 



Bugzilla: 1671904

There are multiple code paths where an hrtimer may have been started to
emulate an L1 VMX preemption timer that can result in a call to free_nested
without an intervening L2 exit where the hrtimer is normally
cancelled. Unconditionally cancel in free_nested to cover all cases.

Embargoed until Feb 7th 2019.

Signed-off-by: default avatarPeter Shier <pshier@google.com>
Reported-by: default avatarJim Mattson <jmattson@google.com>
Reviewed-by: default avatarJim Mattson <jmattson@google.com>
Reported-by: default avatarFelix Wilhelm <fwilhelm@google.com>
Cc: stable@kernel.org
Message-Id: <20181011184646.154065-1-pshier@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 353c0956

arch/x86/kvm/vmx/nested.c

+1 −0
Original line number Diff line number Diff line
@@ -211,6 +211,7 @@ static void free_nested(struct kvm_vcpu *vcpu) 
	if (!vmx->nested.vmxon && !vmx->nested.smm.vmxon)

		return;



	hrtimer_cancel(&vmx->nested.preemption_timer);

	vmx->nested.vmxon = false;

	vmx->nested.smm.vmxon = false;

	free_vpid(vmx->nested.vpid02);