On Thu, Aug 23, 2018 at 6:17 PM, Gustavo A. R. Silva
<gustavo@xxxxxxxxxxxxxx> 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 = kzalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_ATOMIC);
>
> Instead of leaving these open-coded and prone to type mistakes, we can
> now use the new struct_size() helper:
>
> instance = kzalloc(struct_size(instance, entry, count), GFP_ATOMIC);
>
> This issue was detected with the help of Coccinelle.
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
-Kees
> ---
> drivers/soc/qcom/rpmh.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c
> index c7beb68..12c057a 100644
> --- a/drivers/soc/qcom/rpmh.c
> +++ b/drivers/soc/qcom/rpmh.c
> @@ -362,8 +362,7 @@ int rpmh_write_batch(const struct device *dev, enum rpmh_state state,
> if (!count)
> return -EINVAL;
>
> - req = kzalloc(sizeof(*req) + count * sizeof(req->rpm_msgs[0]),
> - GFP_ATOMIC);
> + req = kzalloc(struct_size(req, rpm_msgs, count), GFP_ATOMIC);
> if (!req)
> return -ENOMEM;
> req->count = count;
> --
> 2.7.4
>
--
Kees Cook
Pixel Security
