option: Do not try to bind to ADB interfaces

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Mon, Jul 23, 2018 at 04:02:20PM +0200, Romain Izard wrote:
> Some modems now use the Android Debug Bridge to provide a debugging
> interface, and some phones can also export serial ports managed by the
> "option" driver.
> 
> The ADB daemon running in userspace tries to use USB interfaces with
> bDeviceClass=0xFF, bDeviceSubClass=0x42, bDeviceProtocol=1
> 
> Prevent the option driver from binding to those interfaces, as they
> will not be serial ports.
> 
> This can fix issues like:
> https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=781256
> 
> Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>
> Cc: stable <stable@vger.kernel.org>
> ---
>  drivers/usb/serial/option.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/usb/serial/option.c b/drivers/usb/serial/option.c
> index 664e61f16b6a..f98943a57ff0 100644
> --- a/drivers/usb/serial/option.c
> +++ b/drivers/usb/serial/option.c
> @@ -1987,6 +1987,12 @@ static int option_probe(struct usb_serial *serial,
>  	if (iface_desc->bInterfaceClass == USB_CLASS_MASS_STORAGE)
>  		return -ENODEV;
>  
> +	/* Do not bind Android Debug Bridge interfaces */
> +	if (iface_desc->bInterfaceClass == USB_CLASS_VENDOR_SPEC &&
> +		iface_desc->bInterfaceSubClass == 0x42 &&
> +		iface_desc->bInterfaceProtocol == 1)
> +		return -ENODEV;

Shouldn't you also check the vendor/product id as well?  Otherwise this
has the potential to match random devices that are not really adb
devices.

thanks,

greg k-h
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