Input: ims-pcu - validate number of endpoints before using them

Make sure to check the number of endpoints to avoid dereferencing a
NULL-pointer should a malicious device lack control-interface endpoints.

Fixes: 628329d52474 ("Input: add IMS Passenger Control Unit driver")
Signed-off-by: Johan Hovold <johan@kernel.org>
Cc: stable@vger.kernel.org	# 3.10
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/drivers/input/misc/ims-pcu.c b/drivers/input/misc/ims-pcu.c
index 9c0ea36..f4e8fbe 100644 (file)
--- a/drivers/input/misc/ims-pcu.c
+++ b/drivers/input/misc/ims-pcu.c
@@ -1667,6 +1667,10 @@ static int ims_pcu_parse_cdc_data(struct usb_interface *intf, struct ims_pcu *pc
                return -EINVAL;
 
        alt = pcu->ctrl_intf->cur_altsetting;
+
+       if (alt->desc.bNumEndpoints < 1)
+               return -ENODEV;
+
        pcu->ep_ctrl = &alt->endpoint[0].desc;
        pcu->max_ctrl_size = usb_endpoint_maxp(pcu->ep_ctrl);