[PATCH 4.4 197/210] Input: ims-pcu - sanity check against missing interfaces

[Greg Kroah-Hartman]

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

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

From: Oliver Neukum <oneukum@xxxxxxxx>

commit a0ad220c96692eda76b2e3fd7279f3dcd1d8a8ff upstream.

A malicious device missing interface can make the driver oops.
Add sanity checking.

Signed-off-by: Oliver Neukum <ONeukum@xxxxxxxx>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 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
@@ -1663,6 +1663,8 @@ static int ims_pcu_parse_cdc_data(struct
 
 	pcu->ctrl_intf = usb_ifnum_to_if(pcu->udev,
 					 union_desc->bMasterInterface0);
+	if (!pcu->ctrl_intf)
+		return -EINVAL;
 
 	alt = pcu->ctrl_intf->cur_altsetting;
 	pcu->ep_ctrl = &alt->endpoint[0].desc;
@@ -1670,6 +1672,8 @@ static int ims_pcu_parse_cdc_data(struct
 
 	pcu->data_intf = usb_ifnum_to_if(pcu->udev,
 					 union_desc->bSlaveInterface0);
+	if (!pcu->data_intf)
+		return -EINVAL;
 
 	alt = pcu->data_intf->cur_altsetting;
 	if (alt->desc.bNumEndpoints != 2) {