linux-ext4 - Re: [PATCH 1/2] ext2: Add sanity checks for group and filesystem size

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Date:   Wed, 21 Sep 2022 09:52:27 +0200
From:   Jan Kara <jack@...e.cz>
To:     linux-ext4@...r.kernel.org
Cc:     Jan Kara <jack@...e.cz>,
        syzbot+0f2f7e65a3007d39539f@...kaller.appspotmail.com
Subject: Re: [PATCH 1/2] ext2: Add sanity checks for group and filesystem size

On Wed 14-09-22 17:47:22, Jan Kara wrote:
> Add sanity check that filesystem size does not exceed the underlying
> device size and that group size is big enough so that metadata can fit
> into it. This avoid trying to mount some crafted filesystems with
> extremely large group counts.
> 
> Reported-by: syzbot+0f2f7e65a3007d39539f@...kaller.appspotmail.com
> Signed-off-by: Jan Kara <jack@...e.cz>
...
> +	/* At least inode table, bitmaps, and sb have to fit in one group */
> +	if (sbi->s_blocks_per_group <= sbi->s_inodes_per_group + 3) {

Indeed this should have been comparing against number of inode *table
blocks*, not number of inodes... I've fixed the patch locally, the result
is attached for reference.

								Honza
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR

View attachment "0001-ext2-Add-sanity-checks-for-group-and-filesystem-size.patch" of type "text/x-patch" (2117 bytes)