path: root/virt/kvm/ioapic.c
diff options
authorPaolo Bonzini <pbonzini@redhat.com>2014-03-28 20:41:50 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-05-13 13:59:41 +0200
commita9ded882d5168e2fd5c0c20e2874f85c56016b4b (patch)
treeab9076c701ab8c483863d4ccec2372173a3e9cc0 /virt/kvm/ioapic.c
parentb6b461e90f8fbebb8fa46f363999ed5023be7d3c (diff)
KVM: ioapic: fix assignment of ioapic->rtc_status.pending_eoi (CVE-2014-0155)
commit 5678de3f15010b9022ee45673f33bcfc71d47b60 upstream. QE reported that they got the BUG_ON in ioapic_service to trigger. I cannot reproduce it, but there are two reasons why this could happen. The less likely but also easiest one, is when kvm_irq_delivery_to_apic does not deliver to any APIC and returns -1. Because irqe.shorthand == 0, the kvm_for_each_vcpu loop in that function is never reached. However, you can target the similar loop in kvm_irq_delivery_to_apic_fast; just program a zero logical destination address into the IOAPIC, or an out-of-range physical destination address. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'virt/kvm/ioapic.c')
1 files changed, 1 insertions, 1 deletions
diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index 2d682977ce82..39dc5bc742e0 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -306,7 +306,7 @@ static int ioapic_deliver(struct kvm_ioapic *ioapic, int irq, bool line_status)
BUG_ON(ioapic->rtc_status.pending_eoi != 0);
ret = kvm_irq_delivery_to_apic(ioapic->kvm, NULL, &irqe,
- ioapic->rtc_status.pending_eoi = ret;
+ ioapic->rtc_status.pending_eoi = (ret < 0 ? 0 : ret);
} else
ret = kvm_irq_delivery_to_apic(ioapic->kvm, NULL, &irqe, NULL);