Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Fri, 16 Feb 2018 07:56:17 -0800
From:   Richard Cochran <richardcochran@gmail.com>
To:     "Gustavo A. R. Silva" <garsilva@embeddedor.com>
Cc:     Brandon Streiff <brandon.streiff@ni.com>,
        Andrew Lunn <andrew@lunn.ch>,
        Vivien Didelot <vivien.didelot@savoirfairelinux.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] net: dsa: mv88e6xxx: hwtstamp: fix potential negative
 array index read
Message-ID: <20180216155617.ykf77vq45bxejfg3@localhost>
References: <20180215183139.GA23076@embeddedor.com>
 <20180216154846.7ge6seynwxjkopmp@localhost>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20180216154846.7ge6seynwxjkopmp@localhost>
User-Agent: NeoMutt/20170113 (1.7.2)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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