On Mon, Sep 08, 2014 at 01:32:33PM +0200, Johan Hovold wrote:
> On Fri, Sep 05, 2014 at 06:17:57PM +0300, Octavian Purdila wrote:
> > +static int _dln2_transfer(struct dln2_dev *dln2, u16 handle, u16 cmd,
> > + void *obuf, int obuf_len, void *ibuf, int *ibuf_len)
> > +{
<snip>
> > + /* if we got here we know that the response header has been checked */
> > + rsp = rxc->urb->transfer_buffer;
> > + result = le16_to_cpu(rsp->result);
>
> Yes, but you haven't verified that rsp->hdr.size > 0, so you may still
> be reading stale data.
I meant that you haven't verified that the payload size > 1 (the header
size is included in rsp->hdr.size and result is two byte wide).
> > +
> > + if (result) {
> > + dev_dbg(dev, "%d received response with error %d\n",
> > + handle, result);
> > + ret = -EREMOTEIO;
> > + goto out_free_rx_slot;
> > + }
> > +
> > + if (!ibuf) {
> > + ret = 0;
> > + goto out_free_rx_slot;
> > + }
> > +
> > + if (*ibuf_len > rxc->urb->actual_length - sizeof(*rsp))
> > + *ibuf_len = rxc->urb->actual_length - sizeof(*rsp);
>
> And then you get an underflow here, although that doesn't seem to cause
> any troubles in this case.
Unless ibuf_len is -1...
> But why isn't ibuf_len unsigned?
>
> > +
> > + memcpy(ibuf, rsp + 1, *ibuf_len);
> > +
> > +out_free_rx_slot:
> > + free_rx_slot(dln2, rxs, rx_slot);
> > +
> > + return ret;
> > +}
Johan
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