USB: adutux: fix interface sanity check

commit 3c11c4bed02b202e278c0f5c319ae435d7fb9815 upstream.

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

Failing to do so 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: 03270634e242 ("USB: Add ADU support for Ontrak ADU devices")
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20191210112601.3561-3-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/usb/misc/adutux.c b/drivers/usb/misc/adutux.c
index 684ce2ad1a3930ca7035e066ea5712a0eb4bc7fc..ab5be88930d7865ed52cb1918ad3c05456e112d1 100644 (file)
--- a/drivers/usb/misc/adutux.c
+++ b/drivers/usb/misc/adutux.c
@@ -682,7 +682,7 @@ static int adu_probe(struct usb_interface *interface,
        init_waitqueue_head(&dev->read_wait);
        init_waitqueue_head(&dev->write_wait);
 
-       iface_desc = &interface->altsetting[0];
+       iface_desc = interface->cur_altsetting;
 
        /* set up the endpoint information */
        for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {