From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f67.google.com ([209.85.160.67]:34921 "EHLO mail-pl0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752514AbeDTW0v (ORCPT ); Fri, 20 Apr 2018 18:26:51 -0400 Received: by mail-pl0-f67.google.com with SMTP id w21-v6so5969918plq.2 for ; Fri, 20 Apr 2018 15:26:51 -0700 (PDT) From: Harsh Shandilya To: stable@vger.kernel.org Cc: Theodore Ts'o , Harsh Shandilya Subject: [PATCH 3/4] ext4: don't allow r/w mounts if metadata blocks overlap the superblock Date: Sat, 21 Apr 2018 03:56:11 +0530 Message-Id: <20180420222612.18881-4-harsh@prjkt.io> In-Reply-To: <20180420222612.18881-1-harsh@prjkt.io> References: <20180420222612.18881-1-harsh@prjkt.io> Sender: stable-owner@vger.kernel.org List-ID: From: Theodore Ts'o 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: Harsh Shandilya --- fs/ext4/super.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index cc0a2298099d..263a2f9802f8 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -2093,6 +2093,8 @@ static int ext4_check_descriptors(struct super_block *sb, 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: " @@ -2105,6 +2107,8 @@ static int ext4_check_descriptors(struct super_block *sb, 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: " @@ -2117,6 +2121,8 @@ static int ext4_check_descriptors(struct super_block *sb, 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) { -- 2.15.0.2308.g658a28aa74af