Re: [PATCH] Input: mtk-pmic-keys - match loop with count

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

Hi Rosen,

On Tue, May 26, 2026 at 05:45:43PM -0700, Rosen Penev wrote:
> of_get_available_child_count is used along with
> for_each_child_of_node_scoped, which can cause a mismatch when keys have
> a disabled status.
> 
> If a disabled child node exists in the device tree alongside available ones,
> the loop could execute more times than the initial validation accounted for.
> This might increment the index variable past the allocated array bounds,
> leading to out-of-bounds accesses on irqnames[] and keys->keys[].
> 
> Signed-off-by: Rosen Penev <rosenp@gmail.com>
> ---
>  drivers/input/keyboard/mtk-pmic-keys.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/input/keyboard/mtk-pmic-keys.c b/drivers/input/keyboard/mtk-pmic-keys.c
> index c78d9f6d97c4..5d4ebbafd276 100644
> --- a/drivers/input/keyboard/mtk-pmic-keys.c
> +++ b/drivers/input/keyboard/mtk-pmic-keys.c
> @@ -363,7 +363,7 @@ static int mtk_pmic_keys_probe(struct platform_device *pdev)
>  		return -EINVAL;
>  	}
>  
> -	for_each_child_of_node_scoped(node, child) {
> +	for_each_available_child_of_node_scoped(node, child) {
>  		keys->keys[index].regs = &mtk_pmic_regs->keys_regs[index];
>  
>  		keys->keys[index].irq =

I think Sashiko correctly points out that this may result in incorrect
register data and interrupts being mapped to the keys (potentially
shifting them).

Maybe we should stop counting nodes separately, iterate over all of them
here and bail out with an error if we encounter more than 2 (does not
matter if they are marked available or not), and then skip not available
nodes? WDYT?

Thanks.

-- 
Dmitry