Re: [PATCH v2 1/4] iio: proximity: hx9023s: fix out-of-bounds access when copying firmware

[Krzysztof Kozlowski <krzk@kernel.org>]

On 12/02/2026 14:48, Andy Shevchenko wrote:
> On Thu, Feb 12, 2026 at 12:25:54PM +0100, Krzysztof Kozlowski wrote:
>> On Thu, Feb 12, 2026 at 02:26:52PM +0800, Yasin Lee wrote:
>>> Initialize fw_size before copying firmware data into the flexible
>>> array member to match the __counted_by() annotation. This fixes a
>>> potential out-of-bounds access that could lead to a kernel crash.
>>
>> I don't think so. Code is equivalent and this was just false positive
>> because compiler could not deduce that in this case counted_by can be by
>> fw->size.
> 
> In accordance with [1]:
> 
>    When finding the element count assignment, it must be reordered
>    to before any accesses of the PTR->ARRAY itself, otherwise runtime
>    checking will trigger (i.e. the index of ARRAY will be checked against
>    COUNTER before COUNTER has been assigned the correct COUNT value).
> 
> [1]: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci#L3
> 

Thanks for correcting me. I agree this is a fix but, still, I think this
will no be an out-of-bounds access, because then the runtime checker
will use initial bin->fw_size value of 0.

Best regards,
Krzysztof