[PATCH] can: gs_usb: detach device on reception of invalid USB data

[Marc Kleine-Budde <mkl@pengutronix.de>]

The received data contains the channel the received data is associated
with. If the channel number if bigger than the actual number of
channels assume broken or malicious USB device and shut it down.

This fixes the error found by clang:

| drivers/net/can/usb/gs_usb.c:386:6: error: variable 'dev' is used
|                                     uninitialized whenever 'if' condition is true
|         if (hf->channel >= GS_MAX_INTF)
|             ^~~~~~~~~~~~~~~~~~~~~~~~~~
| drivers/net/can/usb/gs_usb.c:474:10: note: uninitialized use occurs here
|                           hf, dev->gs_hf_size, gs_usb_receive_bulk_callback,
|                               ^~~

Cc: Peter Fink <pfink@christ-es.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/usb/gs_usb.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/usb/gs_usb.c b/drivers/net/can/usb/gs_usb.c
index f8316a26ee35..d33ba13643af 100644
--- a/drivers/net/can/usb/gs_usb.c
+++ b/drivers/net/can/usb/gs_usb.c
@@ -384,7 +384,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 
 	/* device reports out of range channel id */
 	if (hf->channel >= GS_MAX_INTF)
-		goto resubmit_urb;
+		goto device_detach;
 
 	dev = usbcan->canch[hf->channel];
 
@@ -478,6 +478,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 
 	/* USB failure take down all interfaces */
 	if (rc == -ENODEV) {
+ device_detach:
 		for (rc = 0; rc < GS_MAX_INTF; rc++) {
 			if (usbcan->canch[rc])
 				netif_device_detach(usbcan->canch[rc]->netdev);
-- 
2.33.0