Re: [PATCH] USB: core: WARN if pipe direction != setup packet direction

[Greg KH <greg@kroah.com>]

On Fri, May 21, 2021 at 10:03:26AM +0200, Johan Hovold wrote:
> On Thu, May 20, 2021 at 04:20:56PM -0400, Alan Stern wrote:
> > When a control URB is submitted, the direction indicated by URB's pipe
> > member is supposed to match the direction indicated by the setup
> > packet's bRequestType member.  A mismatch could lead to trouble,
> > depending on which field the host controller drivers use for
> > determining the actual direction.
> > 
> > This shouldn't ever happen; it would represent a careless bug in a
> > kernel driver somewhere.  This patch adds a dev_WARN to let people
> > know about the potential problem.
> > 
> > Suggested-by: "Geoffrey D. Bennett" <g@b4.vu>
> > Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
> > 
> > ---
> > 
> > 
> > [as1960]
> > 
> > 
> >  drivers/usb/core/urb.c |    3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > Index: usb-devel/drivers/usb/core/urb.c
> > ===================================================================
> > --- usb-devel.orig/drivers/usb/core/urb.c
> > +++ usb-devel/drivers/usb/core/urb.c
> > @@ -407,6 +407,9 @@ int usb_submit_urb(struct urb *urb, gfp_
> >  			return -ENOEXEC;
> >  		is_out = !(setup->bRequestType & USB_DIR_IN) ||
> >  				!setup->wLength;
> > +		if (usb_pipeout(urb->pipe) != is_out)
> > +			dev_WARN(&dev->dev, "BOGUS control dir, pipe %x doesn't match bRequestType %x\n",
> > +					urb->pipe, setup->bRequestType);
> >  	} else {
> >  		is_out = usb_endpoint_dir_out(&ep->desc);
> >  	}
> 
> While I agree with intention here, I'm worried that this will start
> flooding the logs of users.
> 
> So first, this should probably be rate limited.

That's a good idea, this could get very noisy very quickly if one driver
got it wrong.

thanks,

greg k-h