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=-8.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT 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 08394C43441 for ; Sun, 25 Nov 2018 01:49:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B8CC421104 for ; Sun, 25 Nov 2018 01:49:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="MwfWY1Em" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B8CC421104 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 S1727091AbeKYMjp (ORCPT ); Sun, 25 Nov 2018 07:39:45 -0500 Received: from m12-16.163.com ([220.181.12.16]:36554 "EHLO m12-16.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726722AbeKYMjp (ORCPT ); Sun, 25 Nov 2018 07:39:45 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id; bh=RX0NJVp6kJM8Ft+0zM t/FQ39NY+3juAFTpU724pd67g=; b=MwfWY1EmL5RXre0lTgnqHzPZf2QknSO/hw WggY8AvFWFnOdq3vorfW+AwimhY8iIO/1xOt9due6CjB2IkrDep0OYeJqxECQgjf DERBbECAJBBQ7qGyH3GeCVGxzsc0ZdFT5nkAibPTe+gfQ56iz5qpF+KlA551s6uJ UNZt3xnfc= Received: from bp.localdomain (unknown [106.120.213.96]) by smtp12 (Coremail) with SMTP id EMCowAA3A1Gc__lbW3bNBg--.31965S3; Sun, 25 Nov 2018 09:49:23 +0800 (CST) From: Pan Bian To: Christoph Hellwig Cc: linux-kernel@vger.kernel.org, Pan Bian Subject: [PATCH] freevxfs: set bp to NULL after dropping its reference in loop Date: Sun, 25 Nov 2018 09:49:17 +0800 Message-Id: <1543110557-126460-1-git-send-email-bianpan2016@163.com> X-Mailer: git-send-email 2.7.4 X-CM-TRANSID: EMCowAA3A1Gc__lbW3bNBg--.31965S3 X-Coremail-Antispam: 1Uf129KBjvdXoWrKr1UGr4ftw4kurWkKr4kWFg_yoWfGFXEka 1xJrW8C3yFvr17ta18JFWYqr9IqayrZrn7A342q39Iyry3ta98t3sFvr9xGr1UWrW7WrZ0 k3sFqr1FqryxGjkaLaAFLSUrUUUUUb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUvcSsGvfC2KfnxnUUI43ZEXa7IU8AcTPUUUUU== X-Originating-IP: [106.120.213.96] X-CM-SenderInfo: held01tdqsiiqw6rljoofrz/xtbBUQMKclaD0TL+IAAAsC Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The function vxfs_bmap_indir calls brelse(bh) in the loop and tries to start the next iteration. However, if it happens to break the loop, brelse(bp) will be called again. Resulting in a potential double free bug. This patch assigns NULL to bh after dropping its reference in the loop body. Signed-off-by: Pan Bian --- fs/freevxfs/vxfs_bmap.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/freevxfs/vxfs_bmap.c b/fs/freevxfs/vxfs_bmap.c index 1fd41cf..136e5d1 100644 --- a/fs/freevxfs/vxfs_bmap.c +++ b/fs/freevxfs/vxfs_bmap.c @@ -150,6 +150,7 @@ vxfs_bmap_indir(struct inode *ip, long indir, int size, long block) if (block < off) { brelse(bp); + bp = NULL; continue; } @@ -186,6 +187,7 @@ vxfs_bmap_indir(struct inode *ip, long indir, int size, long block) BUG(); } brelse(bp); + bp = NULL; } fail: -- 2.7.4