Input: sur40 - fix interface sanity checks

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>

diff --git a/drivers/input/touchscreen/sur40.c b/drivers/input/touchscreen/sur40.c
index af96ffcbcffd0ce63776859fc221b49d460301d1..c218ac6c274576e70864e7a91f0f74d2994a1afe 100644 (file)
--- a/drivers/input/touchscreen/sur40.c
+++ b/drivers/input/touchscreen/sur40.c
@@ -357,7 +357,7 @@ static int sur40_probe(struct usb_interface *interface,
        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;