[PATCH 4.14 019/173] mfd: dln2: More sanity checking for endpoints

[Greg Kroah-Hartman]

From: Oliver Neukum <oneukum@xxxxxxxx>

commit 2b8bd606b1e60ca28c765f69c1eedd7d2a2e9dca upstream.

It is not enough to check for the number of endpoints.
The types must also be correct.

Reported-and-tested-by: syzbot+48a2851be24583b864dc@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Oliver Neukum <oneukum@xxxxxxxx>
Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/mfd/dln2.c |   13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

--- a/drivers/mfd/dln2.c
+++ b/drivers/mfd/dln2.c
@@ -729,6 +729,8 @@ static int dln2_probe(struct usb_interfa
 		      const struct usb_device_id *usb_id)
 {
 	struct usb_host_interface *hostif = interface->cur_altsetting;
+	struct usb_endpoint_descriptor *epin;
+	struct usb_endpoint_descriptor *epout;
 	struct device *dev = &interface->dev;
 	struct dln2_dev *dln2;
 	int ret;
@@ -738,12 +740,19 @@ static int dln2_probe(struct usb_interfa
 	    hostif->desc.bNumEndpoints < 2)
 		return -ENODEV;
 
+	epin = &hostif->endpoint[0].desc;
+	epout = &hostif->endpoint[1].desc;
+	if (!usb_endpoint_is_bulk_out(epout))
+		return -ENODEV;
+	if (!usb_endpoint_is_bulk_in(epin))
+		return -ENODEV;
+
 	dln2 = kzalloc(sizeof(*dln2), GFP_KERNEL);
 	if (!dln2)
 		return -ENOMEM;
 
-	dln2->ep_out = hostif->endpoint[0].desc.bEndpointAddress;
-	dln2->ep_in = hostif->endpoint[1].desc.bEndpointAddress;
+	dln2->ep_out = epout->bEndpointAddress;
+	dln2->ep_in = epin->bEndpointAddress;
 	dln2->usb_dev = usb_get_dev(interface_to_usbdev(interface));
 	dln2->interface = interface;
 	usb_set_intfdata(interface, dln2);