Input: sur40 - validate number of endpoints before using them

Make sure to check the number of endpoints to avoid dereferencing a
NULL-pointer or accessing memory that lie beyond the end of the endpoint
array should a malicious device lack the expected endpoints.

Fixes: bdb5c57f209c ("Input: add sur40 driver for Samsung SUR40... ")
Signed-off-by: Johan Hovold <johan@kernel.org>
Cc: stable@vger.kernel.org	# 3.13
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/drivers/input/touchscreen/sur40.c b/drivers/input/touchscreen/sur40.c
index aefb6e11f88a0838917b0a3b7a59dc9eae6b37f2..4c0eecae065c113a26400469d7def3c2b9bcc635 100644 (file)
--- a/drivers/input/touchscreen/sur40.c
+++ b/drivers/input/touchscreen/sur40.c
@@ -527,6 +527,9 @@ static int sur40_probe(struct usb_interface *interface,
        if (iface_desc->desc.bInterfaceClass != 0xFF)
                return -ENODEV;
 
+       if (iface_desc->desc.bNumEndpoints < 5)
+               return -ENODEV;
+
        /* Use endpoint #4 (0x86). */
        endpoint = &iface_desc->endpoint[4].desc;
        if (endpoint->bEndpointAddress != TOUCH_ENDPOINT)