From 960c7339de27c6d6fec13b54880501c3576bb08d Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Mon, 21 Sep 2020 15:59:49 +0200 Subject: USB: cdc-acm: handle broken union descriptors Handle broken union functional descriptors where the master-interface doesn't exist or where its class is of neither Communication or Data type (as required by the specification) by falling back to "combined-interface" probing. Note that this still allows for handling union descriptors with switched interfaces. This specifically makes the Whistler radio scanners TRX series devices work with the driver without adding further quirks to the device-id table. Reported-by: Daniel Caujolle-Bert Tested-by: Daniel Caujolle-Bert Acked-by: Oliver Neukum Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20200921135951.24045-3-johan@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/cdc-acm.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'drivers/usb/class') diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index 3b87e978d972..30137d1b0d8d 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -1241,9 +1241,21 @@ static int acm_probe(struct usb_interface *intf, } } } else { + int class = -1; + data_intf_num = union_header->bSlaveInterface0; control_interface = usb_ifnum_to_if(usb_dev, union_header->bMasterInterface0); data_interface = usb_ifnum_to_if(usb_dev, data_intf_num); + + if (control_interface) + class = control_interface->cur_altsetting->desc.bInterfaceClass; + + if (class != USB_CLASS_COMM && class != USB_CLASS_CDC_DATA) { + dev_dbg(&intf->dev, "Broken union descriptor, assuming single interface\n"); + combined_interfaces = 1; + control_interface = data_interface = intf; + goto look_for_collapsed_interface; + } } if (!control_interface || !data_interface) { -- cgit v1.2.3