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

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Message-ID: <bbfc4bb1-0fc3-daaa-1416-d60a370e6802@embeddedor.com>
Date:   Fri, 16 Feb 2018 11:49:43 -0600
From:   "Gustavo A. R. Silva" <garsilva@...eddedor.com>
To:     Richard Cochran <richardcochran@...il.com>
Cc:     Brandon Streiff <brandon.streiff@...com>,
        Andrew Lunn <andrew@...n.ch>,
        Vivien Didelot <vivien.didelot@...oirfairelinux.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] net: dsa: mv88e6xxx: hwtstamp: fix potential negative
 array index read



On 02/16/2018 09:56 AM, Richard Cochran wrote:
> 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.
> 

I just sent a patch for this.

Thank you both, Andrew and Richard for the feedback.
--
Gustavo