From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Peter Shier Date: Mon, 25 Feb 2019 11:48:06 +0000 Subject: [PATCH] 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: Peter Shier Reported-by: Jim Mattson Reviewed-by: Jim Mattson Reported-by: Felix Wilhelm Cc: stable@kernel.org Message-Id: <20181011184646.154065-1-pshier@google.com> Signed-off-by: Paolo Bonzini CVE-2019-7221 (backported from commit ecec76885bcfe3294685dc363fd1273df0d5d65f) [tyhicks: Backport to 4.18: - free_nested() is in arch/x86/kvm/vmx.c] Signed-off-by: Tyler Hicks Signed-off-by: Thomas Lamprecht --- arch/x86/kvm/vmx.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 7ade6cb125d3..37b095e7f00a 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -7681,6 +7681,7 @@ static void free_nested(struct vcpu_vmx *vmx) 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);