On Thu, 21 Sep 2017, Dan Carpenter wrote: > On Thu, Sep 21, 2017 at 10:17:03AM -0400, Alan Stern wrote: > > On Thu, 21 Sep 2017, Dan Carpenter wrote: > > > > > There used to be an integer overflow check in proc_do_submiturb() but > > > it accidentally got removed. We need to put it back. The > > > > The removal was deliberate, not accidental. :-) > > > > > uurb->buffer_length variable is a signed integer and it's controlled by > > > the user. It can lead to an integer overflow when we do: > > > > > > num_sgs = DIV_ROUND_UP(uurb->buffer_length, USB_SG_SIZE); > > > > Sorry, I don't understand. How can division by 16384 lead to an > > integer overflow? > > It looks like this when you unwrap the macro: > > num_sgs = (uurb->buffer_length + USB_SG_SIZE - 1) / USB_SG_SIZE; > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > This first addition can overflow. Ah, very good point. Okay: Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> Would you like to submit a second patch addressing the other problems I outlined? Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
