Re: [PATCH] USB: legousbtower: fix a signedness bug in tower_probe()

[Dan Carpenter <dan.carpenter@oracle.com>]

On Fri, Oct 11, 2019 at 03:51:26PM +0200, walter harms wrote:
> 
> 
> Am 11.10.2019 15:35, schrieb Dan Carpenter:
> > The problem is that sizeof() is unsigned long so negative error codes
> > are type promoted to high positive values and the condition becomes
> > false.
> > 
> > Fixes: 1d427be4a39d ("USB: legousbtower: fix slab info leak at probe")
> > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> > ---
> >  drivers/usb/misc/legousbtower.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/usb/misc/legousbtower.c b/drivers/usb/misc/legousbtower.c
> > index 9d4c52a7ebe0..835908fe1e65 100644
> > --- a/drivers/usb/misc/legousbtower.c
> > +++ b/drivers/usb/misc/legousbtower.c
> > @@ -881,7 +881,7 @@ static int tower_probe (struct usb_interface *interface, const struct usb_device
> >  				  get_version_reply,
> >  				  sizeof(*get_version_reply),
> >  				  1000);
> > -	if (result < sizeof(*get_version_reply)) {
> > +	if (result < 0 || result < sizeof(*get_version_reply)) {
> >  		if (result >= 0)
> >  			result = -EIO;
> >  		dev_err(idev, "get version request failed: %d\n", result);
> 
> i am not an USB expert but it seems that this is a complicated way
> to check for result != sizeof(*get_version_reply).

Yeah.  You're right.  That would look nicer.  I will resend.

regards,
dan carpenter