Re: Reading the frame number field

On Sat, 14 Apr 2007, Pete Zaitcev wrote:

> On Sat, 14 Apr 2007 12:55:43 -0400 (EDT), Alan Stern <[email protected]> wrote:
> > +	frame_number = usb_get_current_frame_number(ps->dev);
> > +	if (put_user(frame_number, (int __user *)arg))
> > +		return -EFAULT;
> > +	return 0;
> 
> I think it would be safer to test frame_number for being negative and
> return the error in errno rather than the frame number.

An excellent point.  I have added that to the patch.  Now it looks like 
this:

+	frame_number = usb_get_current_frame_number(ps->dev);
+	if (frame_number < 0)
+		return frame_number;
+	if (put_user(frame_number, (int __user *)arg))
+		return -EFAULT;
+	return 0;

Alan Stern


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