linux-kernel - Re: [BUG] hwmon: Widespread TOCTOU vulnerabilities in the hwmon subsystem

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Message-ID: <3401727c-ad93-42df-8130-413eda41ab3a@roeck-us.net>
Date: Thu, 5 Jun 2025 07:37:10 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Gui-Dong Han <hanguidong02@...il.com>
Cc: vt8231@...denengine.co.uk, steve.glendinning@...well.net,
	jdelvare@...e.com, linux-hwmon@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [BUG] hwmon: Widespread TOCTOU vulnerabilities in the hwmon
 subsystem

On Thu, Jun 05, 2025 at 07:33:24AM -0700, Guenter Roeck wrote:
> > 
> > I would like to discuss these issues further and collaborate on the
> > best way to address them comprehensively.
> > 
> 
> I'd suggest to start submitting patches, with the goal of minimizing
> the scope of changes. Sometimes that may mean expanding the scope of
> locks, sometimes it may mean converting macros to functions. When
> converting to functions, it doesn't have to be inline functions: I'd
> leave that up to the compiler to decide. None of that code is performance
> critical.
> 
Actualy, that makes me wonder if it would make sense to introduce
subsystem-level locking. We could introduce a lock in struct
hwmon_device_attribute and lock it whenever a show or store function
executes in drivers/hwmon/hwmon.c. That would only help for drivers
using the _with_info API, but it would simplify driver code a lot.
Any thoughts on that ?

Thanks,
Guenter