On Thu, Aug 23, 2018 at 6:07 PM, Gustavo A. R. Silva
<gust...@embeddedor.com> wrote:
> One of the more common cases of allocation size calculations is finding
> the size of a structure that has a zero-sized array at the end, along
> with memory for some number of elements for that array. For example:
>
> struct foo {
> int stuff;
> void *entry[];
> };
>
> instance = devm_kzalloc(dev, sizeof(struct foo) + sizeof(void *) * count,
> GFP_KERNEL);
>
> Instead of leaving these open-coded and prone to type mistakes, we can
> now use the new struct_size() helper:
>
> instance = devm_kzalloc(dev, struct_size(instance, entry, count), GFP_KERNEL);
>
> This issue was detected with the help of Coccinelle.
>
> Signed-off-by: Gustavo A. R. Silva <gust...@embeddedor.com>
Reviewed-by: Kees Cook <keesc...@chromium.org>
-Kees
> ---
> drivers/memory/atmel-ebi.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/memory/atmel-ebi.c b/drivers/memory/atmel-ebi.c
> index b907865..c3748b4 100644
> --- a/drivers/memory/atmel-ebi.c
> +++ b/drivers/memory/atmel-ebi.c
> @@ -327,8 +327,7 @@ static int atmel_ebi_dev_setup(struct atmel_ebi *ebi,
> struct device_node *np,
> return -EINVAL;
> }
>
> - ebid = devm_kzalloc(ebi->dev,
> - sizeof(*ebid) + (numcs * sizeof(*ebid->configs)),
> + ebid = devm_kzalloc(ebi->dev, struct_size(ebid, configs, numcs),
> GFP_KERNEL);
> if (!ebid)
> return -ENOMEM;
> --
> 2.7.4
>
--
Kees Cook
Pixel Security
