diff options
| author | Paolo Bonzini <pbonzini@redhat.com> | 2014-03-28 20:41:50 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-05-13 13:59:41 +0200 |
| commit | a9ded882d5168e2fd5c0c20e2874f85c56016b4b (patch) | |
| tree | ab9076c701ab8c483863d4ccec2372173a3e9cc0 | |
| parent | b6b461e90f8fbebb8fa46f363999ed5023be7d3c (diff) | |
| download | lwn-a9ded882d5168e2fd5c0c20e2874f85c56016b4b.tar.gz lwn-a9ded882d5168e2fd5c0c20e2874f85c56016b4b.zip | |
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>
| -rw-r--r-- | virt/kvm/ioapic.c | 2 |
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.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); |