[PATCH 4.4 073/103] [media] dib0700: fix NULL-deref at probe

[Greg Kroah-Hartman]

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

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

From: Johan Hovold <johan@xxxxxxxxxx>

commit d5823511c0f8719a39e72ede1bce65411ac653b7 upstream.

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

Fixes: c4018fa2e4c0 ("[media] dib0700: fix RC support on Hauppauge
Nova-TD")

Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/media/usb/dvb-usb/dib0700_core.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/media/usb/dvb-usb/dib0700_core.c
+++ b/drivers/media/usb/dvb-usb/dib0700_core.c
@@ -783,6 +783,9 @@ int dib0700_rc_setup(struct dvb_usb_devi
 
 	/* Starting in firmware 1.20, the RC info is provided on a bulk pipe */
 
+	if (intf->altsetting[0].desc.bNumEndpoints < rc_ep + 1)
+		return -ENODEV;
+
 	purb = usb_alloc_urb(0, GFP_KERNEL);
 	if (purb == NULL) {
 		err("rc usb alloc urb failed");