linux-ext4 - Re: [PATCH v2 1/2] ext4: protect i_disksize update by i_data

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 22 Mar 2018 11:45:37 -0400
From:   "Theodore Y. Ts'o" <tytso@....edu>
To:     Eryu Guan <guaneryu@...il.com>
Cc:     linux-ext4@...r.kernel.org, Jan Kara <jack@...e.cz>
Subject: Re: [PATCH v2 1/2] ext4: protect i_disksize update by i_data_sem in
 direct write path

On Mon, Mar 12, 2018 at 11:21:55PM +0800, Eryu Guan wrote:
> i_disksize update should be protected by i_data_sem, by either taking
> the lock explicitly or by using ext4_update_i_disksize() helper. But the
> i_disksize updates in ext4_direct_IO_write() are not protected at all,
> which may be racing with i_disksize updates in writeback path in
> delalloc buffer write path.
> 
> This is found by code inspection, and I didn't hit any i_disksize
> corruption due to this bug. Thanks to Jan Kara for catching this bug and
> suggesting the fix!
> 
> Reported-by: Jan Kara <jack@...e.cz>
> Suggested-by: Jan Kara <jack@...e.cz>
> Signed-off-by: Eryu Guan <guaneryu@...il.com>

Applied, thanks.

					- Ted