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[23.128.96.18]) by mx.google.com with ESMTP id gz13si12887064pjb.0.2022.01.24.09.18.21; Mon, 24 Jan 2022 09:18:34 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20210112 header.b="goZniMe/"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241532AbiAXGFI (ORCPT + 99 others); Mon, 24 Jan 2022 01:05:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33466 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230091AbiAXGFH (ORCPT ); Mon, 24 Jan 2022 01:05:07 -0500 Received: from mail-ej1-x631.google.com (mail-ej1-x631.google.com [IPv6:2a00:1450:4864:20::631]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C002EC06173B; Sun, 23 Jan 2022 22:05:06 -0800 (PST) Received: by mail-ej1-x631.google.com with SMTP id jx6so18402350ejb.0; Sun, 23 Jan 2022 22:05:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=ElvqKFFJVkkMYsNfH6YMdwcodi4Utdul5mVupZT3qjc=; b=goZniMe/aDJgF/+x+4qLUMWOSzoF3OjjITcvnzQNBM4OWzX8obYYU7RLJ2fKLjuvCd z06EdRf+P2CCDlaJpr7YE9f55Lddk3ixB3s05VoRKIUdq6swUHIEZ+bTSh0+jaNwi9Av PL8W5T94HCiVD9ZlBD8teiXGV0WcozbDcp3kCMRRkeQFC6LbM9WkSMms/nvPtmYJeQ2S I4nsmBLXtydq2FIIMaZNxH528wOCd7EJfov7CGWhFvTtdF3Q2EMtxHdR5C68YBUENQGx NtrOAZlbg2agbKUiZMhHBY8gtzwg1O8hLb5xNNBfIUx8PoVzpra/JwZ6zg76mfxBp2Ei 3a4w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=ElvqKFFJVkkMYsNfH6YMdwcodi4Utdul5mVupZT3qjc=; b=rpVmoffSw3lmpcDEtQPWeBaSeYG9uvJL79T3aC0q1iHjnLkaeQ9T9zr3SNoU51gTp4 dRp4d2d2SbNRoXNcKZJg+JkA7gihnixMFJ/X7pDm+k+rgIm4BYCQH9UbEFddYwDdSG5m IJpMfla1gX9pN7ZqX1dKbZLsU7LbWHKN06VRhpyNYjjWXBIJh3v/LNpC5uFCcCcj8HnW 9q8WcE8Egr+s3nxI5nGYF+CdyJRrQIQioinI+TyAZsq0u6AQC/y8bPn+1QIFfavTBfpH I7021hJrhmaJtHFuEzHT5MDfcdAoQQCnAucMJ5JtbNWwPSC28vNfS8O4RittedgsnxGE vJ3g== X-Gm-Message-State: AOAM5307ZISz8A1GQGHnhqQauBTyFqw9vf+9YIlx2sVCKSEEOcvMItPG eBx4x6Hp+CJJRhT7tzOdf2K0NPuCaePNdZ9i+D8= X-Received: by 2002:a17:907:e8e:: with SMTP id ho14mr4791551ejc.479.1643004304881; Sun, 23 Jan 2022 22:05:04 -0800 (PST) MIME-Version: 1.0 References: <20220120130605.55741-1-dzm91@hust.edu.cn> <8d4b0822-4e94-d124-e191-bec3effaf97c@gmail.com> <192d9115-864f-d2c1-d11b-d75c23c26102@gmail.com> In-Reply-To: <192d9115-864f-d2c1-d11b-d75c23c26102@gmail.com> From: Dongliang Mu Date: Mon, 24 Jan 2022 14:04:38 +0800 Message-ID: Subject: Re: [PATCH] drivers: net: remove a dangling pointer in peak_usb_create_dev To: Pavel Skripkin Cc: Dongliang Mu , Wolfgang Grandegger , Marc Kleine-Budde , "David S. Miller" , Jakub Kicinski , Stephane Grosjean , =?UTF-8?Q?Stefan_M=C3=A4tje?= , Vincent Mailhol , linux-can@vger.kernel.org, "open list:NETWORKING [GENERAL]" , linux-kernel Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jan 23, 2022 at 9:48 PM Pavel Skripkin wrote: > > Hi Dongliang, > > On 1/22/22 09:45, Dongliang Mu wrote: > [...] > > >> Yeah, it seems like (at least based on code), that this dangling pointer > >> is not dangerous, since nothing accesses it. And next_siblings > >> _guaranteed_ to be NULL, since dev->next_siblings is set NULL in > >> disconnect() > > > > Yes, you're right. As a security researcher, I am sensitive to such > > dangling pointers. > > > > As its nullifying site is across functions, I suggest developers > > remove this dangling pointer in case that any newly added code in this > > function or before the nullifying location would touch next_siblings. > > > > Based on git blame this driver is very old (was added in 2012), so, I > guess, nothing really new will come up. > > Anyway, I am absolutely not a security person and if you think, that > this dangling pointer can be somehow used in exploitation you should > state it in commit message. > > > > If Pavel and others think it's fine, then it's time to close this patch. > > > > I don't have any big objections on the code itself. Maybe only 'if' can > be removed to just speed up the code, but I don't see why this change is > needed :) OK, let's move on. Leave alone this patch. > > > > > With regards, > Pavel Skripkin