--- /dev/null
+From: Prasad J Pandit <address@hidden>
+
+USB Ehci emulation supports host controller capability registers.
+But its mmio '.write' function was missing, which lead to a null
+pointer dereference issue. Add a do nothing 'ehci_caps_write'
+definition to avoid it; Do nothing because capability registers
+are Read Only(RO).
+
+Reported-by: Zuozhi Fzz <address@hidden>
+Signed-off-by: Prasad J Pandit <address@hidden>
+
+Upstream-Status: Backport
+https://lists.gnu.org/archive/html/qemu-devel/2016-01/msg05899.html
+
+CVE: CVE-2016-2198
+Signed-off-by: Armin Kuster <akuster@mvista.com>
+
+---
+ hw/usb/hcd-ehci.c | 6 ++++++
+ 1 file changed, 6 insertions(+)
+
+Index: qemu-2.5.0/hw/usb/hcd-ehci.c
+===================================================================
+--- qemu-2.5.0.orig/hw/usb/hcd-ehci.c
++++ qemu-2.5.0/hw/usb/hcd-ehci.c
+@@ -893,6 +893,11 @@ static uint64_t ehci_caps_read(void *ptr
+ return s->caps[addr];
+ }
+
++static void ehci_caps_write(void *ptr, hwaddr addr,
++ uint64_t val, unsigned size)
++{
++}
++
+ static uint64_t ehci_opreg_read(void *ptr, hwaddr addr,
+ unsigned size)
+ {
+@@ -2310,6 +2315,7 @@ static void ehci_frame_timer(void *opaqu
+
+ static const MemoryRegionOps ehci_mmio_caps_ops = {
+ .read = ehci_caps_read,
++ .write = ehci_caps_write,
+ .valid.min_access_size = 1,
+ .valid.max_access_size = 4,
+ .impl.min_access_size = 1,
