From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:60612 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729398AbeIMSyV (ORCPT ); Thu, 13 Sep 2018 14:54:21 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tetsuo Handa , syzbot , "=?UTF-8?q?Ernesto=20A . =20Fern=C3=A1ndez?=" , Andrew Morton , Al Viro , Linus Torvalds , Sasha Levin Subject: [PATCH 4.14 022/115] hfsplus: dont return 0 when fill_super() failed Date: Thu, 13 Sep 2018 15:30:42 +0200 Message-Id: <20180913131824.955710544@linuxfoundation.org> In-Reply-To: <20180913131823.327472833@linuxfoundation.org> References: <20180913131823.327472833@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tetsuo Handa [ Upstream commit 7464726cb5998846306ed0a7d6714afb2e37b25d ] syzbot is reporting NULL pointer dereference at mount_fs() [1]. This is because hfsplus_fill_super() is by error returning 0 when hfsplus_fill_super() detected invalid filesystem image, and mount_bdev() is returning NULL because dget(s->s_root) == NULL if s->s_root == NULL, and mount_fs() is accessing root->d_sb because IS_ERR(root) == false if root == NULL. Fix this by returning -EINVAL when hfsplus_fill_super() detected invalid filesystem image. [1] https://syzkaller.appspot.com/bug?id=21acb6850cecbc960c927229e597158cf35f33d0 Link: http://lkml.kernel.org/r/d83ce31a-874c-dd5b-f790-41405983a5be@I-love.SAKURA.ne.jp Signed-off-by: Tetsuo Handa Reported-by: syzbot Reviewed-by: Ernesto A. Fernández Reviewed-by: Andrew Morton Cc: Al Viro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/hfsplus/super.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/fs/hfsplus/super.c +++ b/fs/hfsplus/super.c @@ -524,8 +524,10 @@ static int hfsplus_fill_super(struct sup goto out_put_root; if (!hfs_brec_read(&fd, &entry, sizeof(entry))) { hfs_find_exit(&fd); - if (entry.type != cpu_to_be16(HFSPLUS_FOLDER)) + if (entry.type != cpu_to_be16(HFSPLUS_FOLDER)) { + err = -EINVAL; goto out_put_root; + } inode = hfsplus_iget(sb, be32_to_cpu(entry.folder.id)); if (IS_ERR(inode)) { err = PTR_ERR(inode);