[PATCH 4/4][CVE-2016-3689] Input: ims-pcu - sanity check against missing interfaces

[Luis Henriques]

From: Oliver Neukum <oneukum at suse.com>

commit a0ad220c96692eda76b2e3fd7279f3dcd1d8a8ff upstream.

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

Signed-off-by: Oliver Neukum <ONeukum at suse.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov at gmail.com>
Signed-off-by: Ben Hutchings <ben at decadent.org.uk>

CVE-2016-3689
BugLink: https://bugs.launchpad.net/bugs/1566581
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 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 719410feb84b..32ba2cf8fdcd 100644
--- 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 usb_interface *intf, struct ims_pcu *pc
 
 	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 usb_interface *intf, struct ims_pcu *pc
 
 	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) {