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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,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 8D332ECDE5F for ; Mon, 23 Jul 2018 12:43:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5337620880 for ; Mon, 23 Jul 2018 12:43:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5337620880 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org 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 S2388898AbeGWNo0 (ORCPT ); Mon, 23 Jul 2018 09:44:26 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:48088 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388318AbeGWNoZ (ORCPT ); Mon, 23 Jul 2018 09:44:25 -0400 Received: from localhost (LFbn-1-12238-233.w90-92.abo.wanadoo.fr [90.92.53.233]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 43F44C83; Mon, 23 Jul 2018 12:43:22 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, OGAWA Hirofumi , syzbot+90b8e10515ae88228a92@syzkaller.appspotmail.com, Andrew Morton , Linus Torvalds Subject: [PATCH 4.4 003/107] fat: fix memory allocation failure handling of match_strdup() Date: Mon, 23 Jul 2018 14:40:57 +0200 Message-Id: <20180723122413.127871500@linuxfoundation.org> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180723122413.003644357@linuxfoundation.org> References: <20180723122413.003644357@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: OGAWA Hirofumi commit 35033ab988c396ad7bce3b6d24060c16a9066db8 upstream. In parse_options(), if match_strdup() failed, parse_options() leaves opts->iocharset in unexpected state (i.e. still pointing the freed string). And this can be the cause of double free. To fix, this initialize opts->iocharset always when freeing. Link: http://lkml.kernel.org/r/8736wp9dzc.fsf@mail.parknet.co.jp Signed-off-by: OGAWA Hirofumi Reported-by: syzbot+90b8e10515ae88228a92@syzkaller.appspotmail.com Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/fat/inode.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) --- a/fs/fat/inode.c +++ b/fs/fat/inode.c @@ -613,13 +613,21 @@ static void fat_set_state(struct super_b brelse(bh); } +static void fat_reset_iocharset(struct fat_mount_options *opts) +{ + if (opts->iocharset != fat_default_iocharset) { + /* Note: opts->iocharset can be NULL here */ + kfree(opts->iocharset); + opts->iocharset = fat_default_iocharset; + } +} + static void delayed_free(struct rcu_head *p) { struct msdos_sb_info *sbi = container_of(p, struct msdos_sb_info, rcu); unload_nls(sbi->nls_disk); unload_nls(sbi->nls_io); - if (sbi->options.iocharset != fat_default_iocharset) - kfree(sbi->options.iocharset); + fat_reset_iocharset(&sbi->options); kfree(sbi); } @@ -1034,7 +1042,7 @@ static int parse_options(struct super_bl opts->fs_fmask = opts->fs_dmask = current_umask(); opts->allow_utime = -1; opts->codepage = fat_default_codepage; - opts->iocharset = fat_default_iocharset; + fat_reset_iocharset(opts); if (is_vfat) { opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95; opts->rodir = 0; @@ -1184,8 +1192,7 @@ static int parse_options(struct super_bl /* vfat specific */ case Opt_charset: - if (opts->iocharset != fat_default_iocharset) - kfree(opts->iocharset); + fat_reset_iocharset(opts); iocharset = match_strdup(&args[0]); if (!iocharset) return -ENOMEM; @@ -1776,8 +1783,7 @@ out_fail: iput(fat_inode); unload_nls(sbi->nls_io); unload_nls(sbi->nls_disk); - if (sbi->options.iocharset != fat_default_iocharset) - kfree(sbi->options.iocharset); + fat_reset_iocharset(&sbi->options); sb->s_fs_info = NULL; kfree(sbi); return error;