linux-kernel - Re: [PATCH] atm/fore200e: Consolidate available cell rate update to prevent race condition

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] [day] [month] [year] [list]

Message-ID: <20240614122341.GK8447@kernel.org>
Date: Fri, 14 Jun 2024 13:23:41 +0100
From: Simon Horman <horms@...nel.org>
To: Gui-Dong Han <hanguidong02@...look.com>
Cc: 3chas3@...il.com, linux-atm-general@...ts.sourceforge.net,
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
	baijiaju1990@...il.com
Subject: Re: [PATCH] atm/fore200e: Consolidate available cell rate update to
 prevent race condition

On Tue, Jun 11, 2024 at 11:54:10AM +0800, Gui-Dong Han wrote:
> In fore200e_change_qos, there is a race condition due to two consecutive
> updates to the 'available_cell_rate' variable. If a read operation 
> occurs between these updates, an intermediate value might be read, 
> leading to potential bugs.
> 
> To fix this issue, 'available_cell_rate' should be adjusted in a single 
> operation, ensuring consistency and preventing any intermediate states 
> from being read.
> 
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Signed-off-by: Gui-Dong Han <hanguidong02@...look.com>

Hi Gui-Dong Han,

If there is a race involving writing and reading available_cell_rate,
then I believe there is still a race after your patch: if nothing protects
to protect available_cell_rate from being read while it is written then
that is true both before and after this patch.

Also, I would suggest that this is a very old and possibly unused driver.
If you wish to spend time on it I'd suggest that time go into
investigating if it is appropriate to remove the driver entirely.