Re: [PATCH v3 net-next] mdio-mux-gpio: Remove VLA usage

From: Kees Cook
Date: Mon Jun 25 2018 - 18:39:32 EST


On Mon, Jun 25, 2018 at 3:23 PM, Joe Perches <joe@xxxxxxxxxxx> wrote:
> On Mon, 2018-06-25 at 15:09 -0700, Kees Cook wrote:
>> In the quest to remove all stack VLA usage from the kernel[1], this
>> allocates the values buffer during the callback instead of putting it
>> on the stack.
>
> []
>
>> diff --git a/drivers/net/phy/mdio-mux-gpio.c b/drivers/net/phy/mdio-mux-gpio.c
> []
>> @@ -44,15 +44,21 @@ static int mdio_mux_gpio_switch_fn(int current_child, int desired_child,
>> static int mdio_mux_gpio_probe(struct platform_device *pdev)
>> {
> []
>> + s = devm_kzalloc(&pdev->dev, sizeof(*s->values) * gpios->ndescs +
>> + sizeof(*s), GFP_KERNEL);
>
> Isn't this supposed to use your new struct_size()

Why yes. Yes it is. :) When treewide changes meet in the night! :)
I'll send a v4.

-Kees

--
Kees Cook
Pixel Security