From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D3F68C4CECD for ; Fri, 20 Sep 2019 12:45:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AEEE1208C0 for ; Fri, 20 Sep 2019 12:45:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726234AbfITMpv (ORCPT ); Fri, 20 Sep 2019 08:45:51 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:35040 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725858AbfITMpv (ORCPT ); Fri, 20 Sep 2019 08:45:51 -0400 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92.2 #3 (Red Hat Linux)) id 1iBII0-0005O2-Mk; Fri, 20 Sep 2019 12:45:33 +0000 Date: Fri, 20 Sep 2019 13:45:32 +0100 From: Al Viro To: Xiaoming Ni Cc: dwmw2@infradead.org, dilinger@queued.net, richard@nod.at, houtao1@huawei.com, bbrezillon@kernel.org, daniel.santos@pobox.com, linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] jffs2:freely allocate memory when parameters are invalid Message-ID: <20190920124532.GN1131@ZenIV.linux.org.uk> References: <1568962478-126260-1-git-send-email-nixiaoming@huawei.com> <20190920114336.GM1131@ZenIV.linux.org.uk> <206f8d57-dad9-26c3-6bf6-1d000f5698d4@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <206f8d57-dad9-26c3-6bf6-1d000f5698d4@huawei.com> User-Agent: Mutt/1.12.0 (2019-05-25) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 20, 2019 at 08:21:53PM +0800, Xiaoming Ni wrote: > > > On 2019/9/20 19:43, Al Viro wrote: > > On Fri, Sep 20, 2019 at 02:54:38PM +0800, Xiaoming Ni wrote: > >> Use kzalloc() to allocate memory in jffs2_fill_super(). > >> Freeing memory when jffs2_parse_options() fails will cause > >> use-after-free and double-free in jffs2_kill_sb() > > > > ... so we are not freeing it there. What's the problem? > > No code logic issues, no memory leaks > > But there is too much code logic between memory allocation and free, > which is difficult to understand. Er? An instance of jffs2 superblock might have a related object attached to it; it is created in jffs2 superblock constructor and freed in destructor. > The modified code is easier to understand. You are making the cleanup logics harder to follow.