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=-8.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, FREEMAIL_REPLYTO_END_DIGIT,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 3C65BC04EB9 for ; Mon, 3 Dec 2018 09:15:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 00A7821473 for ; Mon, 3 Dec 2018 09:15:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="pulffLmJ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 00A7821473 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=163.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726022AbeLCJPK (ORCPT ); Mon, 3 Dec 2018 04:15:10 -0500 Received: from m12-12.163.com ([220.181.12.12]:46139 "EHLO m12-12.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725872AbeLCJPK (ORCPT ); Mon, 3 Dec 2018 04:15:10 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=Date:From:Subject:Message-ID:MIME-Version; bh=Qpbfx 09WsH0vUx9H/ZJVpKs7ntILqCAHmG4x4+GbK1E=; b=pulffLmJJjzQNiSl0ODUd GlelITUZbC3ZJbxi5YLcVIfTGKHvCozRVmOKeyVTk096WFEUkyn2MYxOdsF1mb8D i/OMFbyLHrY+SnbNDq5n0bepkU7PWEQDqFLTuX3wnVX8sd11x8OXiqh/y7tshx52 2tvqpqRpD/qtw+PxXqXADM= Received: from bp (unknown [106.120.213.96]) by smtp8 (Coremail) with SMTP id DMCowAAHHtIO9ARcclOlDA--.48858S2; Mon, 03 Dec 2018 17:14:54 +0800 (CST) Date: Mon, 3 Dec 2018 17:14:55 +0800 From: PanBian To: Ryusuke Konishi Cc: linux-nilfs@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] nilfs2: fix potential use after free Message-ID: <20181203091455.GA9038@bp> Reply-To: PanBian References: <1543201709-53191-1-git-send-email-bianpan2016@163.com> <20181203.181051.1348099310050315226.konishi.ryusuke@lab.ntt.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181203.181051.1348099310050315226.konishi.ryusuke@lab.ntt.co.jp> User-Agent: Mutt/1.5.24 (2015-08-30) X-CM-TRANSID: DMCowAAHHtIO9ARcclOlDA--.48858S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7tryUKF48Xr1UtFy5Zw43KFg_yoW8Ar1rpr WfK3W3CanYqa4vgF1Igr15Zw1Fqa9rtr4DGFyDG3WFyr43t3Z7KFyxKrnF9a4UAr93CrZY vrWjgF9F9wn5JaDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07jPKsUUUUUU= X-Originating-IP: [106.120.213.96] X-CM-SenderInfo: held01tdqsiiqw6rljoofrz/1tbiVA4SclUMGPz94AAAsa Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 03, 2018 at 06:10:51PM +0900, Ryusuke Konishi wrote: > Hi, Pan Bian > > Thank you for feeding back this patch. > I reviewed this and am thinking this must be sent to upstream. > > Did you see any kernel oops on this bug ? Not yet. In fact, I found it with a static method. Best regards, Pan Bian > > Regards, > Ryusuke Konishi > > On Mon, 26 Nov 2018 11:08:29 +0800, Pan Bian wrote: > > brelse(bh) is called to drop the reference count of bh when the call > > to nilfs_dat_translate fails. If the reference count hits 0, bh may be > > freed. However, bh->b_page is unlocked and put after that, which may > > result in a use-after-free bug. This patch moves the release operation > > after unlocking and putting the page. > > > > Signed-off-by: Pan Bian > > --- > > fs/nilfs2/gcinode.c | 6 +++--- > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > diff --git a/fs/nilfs2/gcinode.c b/fs/nilfs2/gcinode.c > > index aa3c328..a24bb29 100644 > > --- a/fs/nilfs2/gcinode.c > > +++ b/fs/nilfs2/gcinode.c > > @@ -73,10 +73,8 @@ int nilfs_gccache_submit_read_data(struct inode *inode, sector_t blkoff, > > struct the_nilfs *nilfs = inode->i_sb->s_fs_info; > > > > err = nilfs_dat_translate(nilfs->ns_dat, vbn, &pbn); > > - if (unlikely(err)) { /* -EIO, -ENOMEM, -ENOENT */ > > - brelse(bh); > > + if (unlikely(err)) /* -EIO, -ENOMEM, -ENOENT */ > > goto failed; > > - } > > } > > > > lock_buffer(bh); > > @@ -102,6 +100,8 @@ int nilfs_gccache_submit_read_data(struct inode *inode, sector_t blkoff, > > failed: > > unlock_page(bh->b_page); > > put_page(bh->b_page); > > + if (unlikely(err)) > > + brelse(bh); > > return err; > > } > > > > -- > > 2.7.4 > > > >