--- /dev/null
+From: Gerd Hoffmann
+Subject: [Qemu-devel] [PULL 5/5] ehci: make idt processing more robust
+
+Make ehci_process_itd return an error in case we didn't do any actual
+iso transfer because we've found no active transaction. That'll avoid
+ehci happily run in circles forever if the guest builds a loop out of
+idts.
+
+This is CVE-2015-8558.
+
+Cc: qemu-stable@nongnu.org
+Reported-by: Qinghao Tang <luodalongde@gmail.com>
+Tested-by: P J P <ppandit@redhat.com>
+Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
+---
+ hw/usb/hcd-ehci.c | 5 +++--
+ 1 file changed, 3 insertions(+), 2 deletions(-)
+
+diff --git a/hw/usb/hcd-ehci.c b/hw/usb/hcd-ehci.c
+index 4e2161b..d07f228 100644
+--- a/hw/usb/hcd-ehci.c
++++ b/hw/usb/hcd-ehci.c
+@@ -1389,7 +1389,7 @@ static int ehci_process_itd(EHCIState *ehci,
+ {
+ USBDevice *dev;
+ USBEndpoint *ep;
+- uint32_t i, len, pid, dir, devaddr, endp;
++ uint32_t i, len, pid, dir, devaddr, endp, xfers = 0;
+ uint32_t pg, off, ptr1, ptr2, max, mult;
+
+ ehci->periodic_sched_active = PERIODIC_ACTIVE;
+@@ -1479,9 +1479,10 @@ static int ehci_process_itd(EHCIState *ehci,
+ ehci_raise_irq(ehci, USBSTS_INT);
+ }
+ itd->transact[i] &= ~ITD_XACT_ACTIVE;
++ xfers++;
+ }
+ }
+- return 0;
++ return xfers ? 0 : -1;
+ }
+
+
+--
+1.8.3.1
+
+
+
+