linux-kernel - Re: [PATCH] iio: accel: fxls8962af: Fix use after free in fxls8962af_fifo

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]

Message-ID: <6825fc30-d8ef-4a10-98ec-79ed303dd145@baylibre.com>
Date: Fri, 30 May 2025 12:57:00 -0500
From: David Lechner <dlechner@...libre.com>
To: Andy Shevchenko <andy.shevchenko@...il.com>
Cc: Sean Nyekjaer <sean@...nix.com>, Jonathan Cameron <jic23@...nel.org>,
 Nuno Sá <nuno.sa@...log.com>,
 Jonathan Cameron <Jonathan.Cameron@...wei.com>, linux-iio@...r.kernel.org,
 linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH] iio: accel: fxls8962af: Fix use after free in
 fxls8962af_fifo_flush

On 5/30/25 12:51 PM, Andy Shevchenko wrote:
> On Thu, May 29, 2025 at 01:49:16PM -0500, David Lechner wrote:
>> On 5/29/25 1:16 PM, Andy Shevchenko wrote:
>>> On Thu, May 29, 2025 at 7:02 PM David Lechner <dlechner@...libre.com> wrote:
>>>> On 5/24/25 5:34 AM, Sean Nyekjaer wrote:
> 
> ...
> 
>>>> fxls8962af_suspend() calls enable_irq_wake(data->irq); before disabling the
>>>> interrupt by calling fxls8962af_buffer_predisable(indio_dev);
>>>>
>>>> It seems like the order should be reversed.
>>>
>>> AFAIU the wake capability of IRQ line is orthogonal to the interrupt
>>> controller enabling (unmasking) / disabling (masking) the line itself.
>>> Or did you mean something else?
>>
>> I don't know enough about how suspend/wake stuff works to say for sure.
>>
>> I just saw the comment:
>>
>> 	/*
>> 	 * Disable buffer, as the buffer is so small the device will wake
>> 	 * almost immediately.
>> 	 */
>>
>> so I assumed someone had observed something like this happening already.
>> If an interrupt occurs between enable_irq_wake() and actually
>> going into a low power mode, what effect does it have? I ask because I
>> don't know.
> 
> To be a "wake source" means to be capable of signaling to the system that wake
> is needed. If an event comes after enabling an IRQ line to be a wake source,
> that should wakeup the system (independently if that IRQ line is disabled or
> not on the IRQ controller side).
> 

OK, more clear now. So I should have been more specific with my previous
comment. When I said, "before disabling the interrupt", I didn't mean
calling disable_irq(). I meant disabling the actual output pin on the
accelerometer chip.