[PATCH 3.16 174/245] Input: sur40 - fix interface sanity checks

Ben Hutchings
2020-04-23T23:13:37Z

From: Johan Hovold <johan@kernel.org>

commit 6b32391ed675827f8425a414abbc6fbd54ea54fe upstream.

Make sure to use the current alternate setting when verifying the
interface descriptors to avoid binding to an invalid interface.

This in turn could cause the driver to misbehave or trigger a WARN() in
usb_submit_urb() that kernels with panic_on_warn set would choke on.

Fixes: bdb5c57f209c ("Input: add sur40 driver for Samsung SUR40 (aka MS Surface 2.0/Pixelsense)")
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Vladis Dronov <vdronov@redhat.com>
Link: https://lore.kernel.org/r/20191210113737.4016-8-johan@kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/input/touchscreen/sur40.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/input/touchscreen/sur40.c
+++ b/drivers/input/touchscreen/sur40.c
@@ -357,7 +357,7 @@ static int sur40_probe(struct usb_interf
int error;

/* Check if we really have the right interface. */
- iface_desc = &interface->altsetting[0];
+ iface_desc = interface->cur_altsetting;
if (iface_desc->desc.bInterfaceClass != 0xFF)
return -ENODEV;