USB: Avoid NULL pointer deref in usb_hcd_alloc_bandwidth.

usb_ifnum_to_if() can return NULL if the USB device does not have a
configuration installed (usb_device->actconfig == NULL), or if we can't
find the interface number in the installed configuration.  Return an
error instead of crashing.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 8669ba3fe794..73cbbd85219f 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -1775,6 +1775,8 @@ int usb_hcd_alloc_bandwidth(struct usb_device *udev,
                 struct usb_interface *iface = usb_ifnum_to_if(udev,
                                 cur_alt->desc.bInterfaceNumber);
 
+                if (!iface)
+                        return -EINVAL;
                 if (iface->resetting_device) {
                         /*
                          * The USB core just reset the device, so the xHCI host