Input: sur40 - fix interface sanity checks

BugLink: https://bugs.launchpad.net/bugs/1864261
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/input/touchscreen/sur40.c b/drivers/input/touchscreen/sur40.c
index f16f8358c70aab09da0cda18a4fa623f7d8a027a..98e03d0ca03cbad73569063e71f4307b100560b0 100644 (file)
--- a/drivers/input/touchscreen/sur40.c
+++ b/drivers/input/touchscreen/sur40.c
@@ -537,7 +537,7 @@ 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;