[PATCH 3.18 079/124] Input: ims-pcu - validate number of endpoints before using them

[Greg Kroah-Hartman]

3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Johan Hovold <jo...@kernel.org>

commit 1916d319271664241b7aa0cd2b05e32bdb310ce9 upstream.

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 <jo...@kernel.org>
Signed-off-by: Dmitry Torokhov <dmitry.torok...@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 drivers/input/misc/ims-pcu.c |    4 ++++
 1 file changed, 4 insertions(+)

--- 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
                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);