Re: [PATCH v2] net: dsa: mv88e6xxx: hwtstamp: fix potential negative array index read

From: Richard Cochran
Date: Fri Feb 16 2018 - 10:56:26 EST


On Fri, Feb 16, 2018 at 07:48:46AM -0800, Richard Cochran wrote:
> On Thu, Feb 15, 2018 at 12:31:39PM -0600, Gustavo A. R. Silva wrote:
> > _port_ is being used as index to array port_hwtstamp before verifying
> > it is a non-negative number and a valid index at line 209 and 258:
> >
> > if (port < 0 || port >= mv88e6xxx_num_ports(chip))
> >
> > Fix this by checking _port_ before using it as index to array
> > port_hwtstamp.
>
> NAK. Port is already known to be valid in the callers.

And so the real bug is the pointless range checking tests. I would
welcome patches to remove those.

Thanks,
Richard