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authorGerd Hoffmann <kraxel@redhat.com>2015-12-14 09:21:23 +0100
committerGerd Hoffmann <kraxel@redhat.com>2015-12-15 09:49:03 +0100
commit156a2e4dbffa85997636a7a39ef12da6f1b40254 (patch)
treec7d18840cfc024eb520ad6032ad49a48b1b5bc4b /hw
parent93d592e3d1a45e4c0b3969e1fbbc459d6df826aa (diff)
downloadqemu-arm-156a2e4dbffa85997636a7a39ef12da6f1b40254.tar.gz
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>
Diffstat (limited to 'hw')
-rw-r--r--hw/usb/hcd-ehci.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/hw/usb/hcd-ehci.c b/hw/usb/hcd-ehci.c
index 4e2161b5a7..d07f228df8 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;
}