[PATCH 3.12 075/142] Input: ims-pcu - validate number of endpoints before using them

[Jiri Slaby]

From: Johan Hovold <johan@xxxxxxxxxx>

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

===============

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 <johan@xxxxxxxxxx>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
 drivers/input/misc/ims-pcu.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/input/misc/ims-pcu.c b/drivers/input/misc/ims-pcu.c
index 77164dc1bedd..8fb814ccfd7a 100644
--- a/drivers/input/misc/ims-pcu.c
+++ b/drivers/input/misc/ims-pcu.c
@@ -1437,6 +1437,10 @@ 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);
 
-- 
2.12.2