Re: [PATCH] Check for changed device descriptors when a connection-change occurs before validating the connection.

[Greg KH <gregkh@linuxfoundation.org>]

On Mon, Oct 07, 2019 at 10:01:47AM -0400, Alan Stern wrote:
> On Mon, 7 Oct 2019, David Heinzelmann wrote:
> 
> > Hi,
> > 
> > I hope it all fits now.
> > 
> > David
> > 
> > 
> > From 8517ecfac0175aebba03bb0868dde652bc3c36e5 Mon Sep 17 00:00:00 2001
> > From: David Heinzelmann <heinzelmann.david@gmail.com>
> > Date: Fri, 4 Oct 2019 12:28:36 +0200
> > Subject: [PATCH v4] usb: hub: Check device descriptor before resusciation
> > 
> > If a device connected to an xHCI host controller disconnects from the USB bus
> > and then reconnects, e.g. triggered by a firmware update, then the host
> > controller automatically activates the connection and the port is enabled. The
> > implementation of hub_port_connect_change() assumes that if the port is
> > enabled then nothing has changed. There is no check if the USB descriptors
> > have changed. As a result, the kernel's internal copy of the descriptors ends
> > up being incorrect and the device doesn't work properly anymore.
> > 
> > The solution to the problem is for hub_port_connect_change() always to
> > check whether the device's descriptors have changed before resuscitating
> > an enabled port.
> > 
> > Signed-off-by: David Heinzelmann <heinzelmann.david@gmail.com>
> 
> Acked-by: Alan Stern <stern@rowland.harvard.edu>

David, can you resend this in a format that I can apply it in?

thanks,

greg k-h