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=-3.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 7D325C65BAF for ; Sun, 9 Dec 2018 22:24:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4E3B020661 for ; Sun, 9 Dec 2018 22:24:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4E3B020661 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=decadent.org.uk 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 S1728697AbeLIWYu (ORCPT ); Sun, 9 Dec 2018 17:24:50 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:34968 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726467AbeLIVzR (ORCPT ); Sun, 9 Dec 2018 16:55:17 -0500 Received: from pub.yeoldevic.com ([81.174.156.145] helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1gW72h-0002pr-AO; Sun, 09 Dec 2018 21:55:15 +0000 Received: from ben by deadeye with local (Exim 4.91) (envelope-from ) id 1gW72e-0003RN-Ew; Sun, 09 Dec 2018 21:55:12 +0000 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Wen Xu" , "Theodore Ts'o" Date: Sun, 09 Dec 2018 21:50:33 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 163/328] ext4: check to make sure the rename(2)'s destination is not freed In-Reply-To: X-SA-Exim-Connect-IP: 81.174.156.145 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.62-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Theodore Ts'o commit b50282f3241acee880514212d88b6049fb5039c8 upstream. If the destination of the rename(2) system call exists, the inode's link count (i_nlinks) must be non-zero. If it is, the inode can end up on the orphan list prematurely, leading to all sorts of hilarity, including a use-after-free. https://bugzilla.kernel.org/show_bug.cgi?id=200931 Signed-off-by: Theodore Ts'o Reported-by: Wen Xu [bwh: Backported to 3.16: - Return -EIO on error - Adjust context] Signed-off-by: Ben Hutchings --- fs/ext4/namei.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -3211,6 +3211,12 @@ static int ext4_rename(struct inode *old int force_reread; int retval; + if (new.inode && new.inode->i_nlink == 0) { + EXT4_ERROR_INODE(new.inode, + "target of rename is already freed"); + return -EIO; + } + dquot_initialize(old.dir); dquot_initialize(new.dir);