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authorPaolo Bonzini <pbonzini@redhat.com>2014-03-28 23:41:50 +0400
committerPaolo Bonzini <pbonzini@redhat.com>2014-04-04 19:17:14 +0400
commit5678de3f15010b9022ee45673f33bcfc71d47b60 (patch)
treef1de2ce3a27fe310faea6a252a88bce39946383c /virt
parent7cbb39d4d4d530dff12f2ff06ed6c85c504ba91a (diff)
downloadlinux-5678de3f15010b9022ee45673f33bcfc71d47b60.tar.xz
KVM: ioapic: fix assignment of ioapic->rtc_status.pending_eoi (CVE-2014-0155)
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>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/ioapic.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index d4b601547f1f..d98d107efb05 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -356,7 +356,7 @@ static int ioapic_service(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.dest_map);
- 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);