From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:46282 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753506AbeDVN6d (ORCPT ); Sun, 22 Apr 2018 09:58:33 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Theodore Tso Subject: [PATCH 4.16 095/196] ext4: dont allow r/w mounts if metadata blocks overlap the superblock Date: Sun, 22 Apr 2018 15:51:55 +0200 Message-Id: <20180422135109.194594813@linuxfoundation.org> In-Reply-To: <20180422135104.278511750@linuxfoundation.org> References: <20180422135104.278511750@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Theodore Ts'o commit 18db4b4e6fc31eda838dd1c1296d67dbcb3dc957 upstream. If some metadata block, such as an allocation bitmap, overlaps the superblock, it's very likely that if the file system is mounted read/write, the results will not be pretty. So disallow r/w mounts for file systems corrupted in this particular way. Signed-off-by: Theodore Ts'o Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- fs/ext4/super.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -2333,6 +2333,8 @@ static int ext4_check_descriptors(struct ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: " "Block bitmap for group %u overlaps " "superblock", i); + if (!sb_rdonly(sb)) + return 0; } if (block_bitmap < first_block || block_bitmap > last_block) { ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: " @@ -2345,6 +2347,8 @@ static int ext4_check_descriptors(struct ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: " "Inode bitmap for group %u overlaps " "superblock", i); + if (!sb_rdonly(sb)) + return 0; } if (inode_bitmap < first_block || inode_bitmap > last_block) { ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: " @@ -2357,6 +2361,8 @@ static int ext4_check_descriptors(struct ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: " "Inode table for group %u overlaps " "superblock", i); + if (!sb_rdonly(sb)) + return 0; } if (inode_table < first_block || inode_table + sbi->s_itb_per_group - 1 > last_block) {