linux-ext4 - Re: [PATCH] ext4: Fix ext4_empty_dir() for directories with holes

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Message-ID: <20191127200015.GC22921@mit.edu>
Date:   Wed, 27 Nov 2019 15:00:15 -0500
From:   "Theodore Y. Ts'o" <tytso@....edu>
To:     Jan Kara <jack@...e.cz>
Cc:     linux-ext4@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH] ext4: Fix ext4_empty_dir() for directories with holes

On Wed, Nov 27, 2019 at 02:12:58PM +0100, Jan Kara wrote:
> Function ext4_empty_dir() doesn't correctly handle directories with
> holes and crashes on bh->b_data dereference when bh is NULL. Reorganize
> the loop to use 'offset' variable all the times instead of comparing
> pointers to current direntry with bh->b_data pointer. Also add more
> strict checking of '.' and '..' directory entries to avoid entering loop
> in possibly invalid state on corrupted filesystems.
> 
> References: CVE-2019-19037
> CC: stable@...r.kernel.org
> Fixes: 4e19d6b65fb4 ("ext4: allow directory holes")
> Signed-off-by: Jan Kara <jack@...e.cz>

Thanks, applied.

					- Ted