From mboxrd@z Thu Jan 1 00:00:00 1970 From: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= Subject: Re: [PATCH 03/10] net/fec: add mac field into platform data and consolidate fec_get_mac Date: Wed, 29 Dec 2010 13:42:21 +0100 Message-ID: <20101229124220.GD14221@pengutronix.de> References: <1293548155-16328-1-git-send-email-shawn.guo@freescale.com> <1293548155-16328-4-git-send-email-shawn.guo@freescale.com> <20101229065329.GB31010@jasper.tkos.co.il> <20101229100520.GB19347@freescale.com> <20101229103138.GT14221@pengutronix.de> <20101229115808.GF19347@freescale.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Baruch Siach , davem@davemloft.net, gerg@snapgear.com, eric@eukrea.com, bryan.wu@canonical.com, r64343@freescale.com, B32542@freescale.com, lw@karo-electronics.de, w.sang@pengutronix.de, s.hauer@pengutronix.de, linux-arm-kernel@lists.infradead.org, netdev@vger.kernel.org To: Shawn Guo Return-path: Received: from metis.ext.pengutronix.de ([92.198.50.35]:56209 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752096Ab0L2Mm5 (ORCPT ); Wed, 29 Dec 2010 07:42:57 -0500 Content-Disposition: inline In-Reply-To: <20101229115808.GF19347@freescale.com> Sender: netdev-owner@vger.kernel.org List-ID: Hello Shawn, On Wed, Dec 29, 2010 at 07:58:09PM +0800, Shawn Guo wrote: > On Wed, Dec 29, 2010 at 11:31:38AM +0100, Uwe Kleine-K=F6nig wrote: > > On Wed, Dec 29, 2010 at 06:05:21PM +0800, Shawn Guo wrote: > > > On Wed, Dec 29, 2010 at 08:53:30AM +0200, Baruch Siach wrote: > > > if (iap =3D=3D fec_mac_default) > > > dev->dev_addr[ETH_ALEN-1] =3D fec_mac_default[ETH_ALEN-1] + fep= ->pdev->id; > > Can this overflow? (I didn't check the code, so my concern might b= e > > completely stupid here.) > No. dev->dev_addr points to netdev_hw_addr->addr, which is a 32 bytes= array. I didn't mean an out-of-bound access, but what is if fec_mac_default[ETH_ALEN-1] is 0xff and you add 1? Does that result in 0x100 or 0? What if id is <0? For big ids you might even handle a carry to indixes