From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750861AbWENRIa (ORCPT ); Sun, 14 May 2006 13:08:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751013AbWENRIa (ORCPT ); Sun, 14 May 2006 13:08:30 -0400 Received: from ftp.linux-mips.org ([194.74.144.162]:49336 "EHLO ftp.linux-mips.org") by vger.kernel.org with ESMTP id S1750861AbWENRI3 (ORCPT ); Sun, 14 May 2006 13:08:29 -0400 Date: Sun, 14 May 2006 18:08:27 +0100 From: Ralf Baechle To: Jesper Juhl Cc: linux-kernel@vger.kernel.org, Frederic Rible , Jean-Paul Roubelat , linux-hams@vger.kernel.org Subject: Re: [PATCH] fix potential NULL pointer dereference in yam Message-ID: <20060514170827.GA24169@linux-mips.org> References: <200605141512.50923.jesper.juhl@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200605141512.50923.jesper.juhl@gmail.com> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, May 14, 2006 at 03:12:50PM +0200, Jesper Juhl wrote: > Testing a pointer for NULL after it has already been dereferenced is not > very safe. > Patch below to rework yam_open() so that `dev' is not dereferenced until > after it has been tested for NULL. It may not obvious and that itself is some sort of bug bug netdev_priv() assumes that the private part of struct netdev has been allocated immediately following struct netdev, so the macro will compile into just pointer arithmetic. So no possible NULL pointer dereference here. Ralf