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 <[email protected]>
---
drivers/mtd/nand/raw/atmel/nand-controller.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/drivers/mtd/nand/raw/atmel/nand-controller.c b/drivers/mtd/nand/raw/atmel/nand-controller.c
index a068b21..b17cfd0 100644
--- a/drivers/mtd/nand/raw/atmel/nand-controller.c
+++ b/drivers/mtd/nand/raw/atmel/nand-controller.c
@@ -1586,9 +1586,7 @@ static struct atmel_nand *atmel_nand_create(struct atmel_nand_controller *nc,
return ERR_PTR(-EINVAL);
}
- nand = devm_kzalloc(nc->dev,
- sizeof(*nand) + (numcs * sizeof(*nand->cs)),
- GFP_KERNEL);
+ nand = devm_kzalloc(nc->dev, struct_size(nand, cs, numcs), GFP_KERNEL);
if (!nand) {
dev_err(nc->dev, "Failed to allocate NAND object\n");
return ERR_PTR(-ENOMEM);
--
2.7.4
On Thu, Aug 23, 2018 at 6:09 PM, Gustavo A. R. Silva
<[email protected]> 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 <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
-Kees
> ---
> drivers/mtd/nand/raw/atmel/nand-controller.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/drivers/mtd/nand/raw/atmel/nand-controller.c b/drivers/mtd/nand/raw/atmel/nand-controller.c
> index a068b21..b17cfd0 100644
> --- a/drivers/mtd/nand/raw/atmel/nand-controller.c
> +++ b/drivers/mtd/nand/raw/atmel/nand-controller.c
> @@ -1586,9 +1586,7 @@ static struct atmel_nand *atmel_nand_create(struct atmel_nand_controller *nc,
> return ERR_PTR(-EINVAL);
> }
>
> - nand = devm_kzalloc(nc->dev,
> - sizeof(*nand) + (numcs * sizeof(*nand->cs)),
> - GFP_KERNEL);
> + nand = devm_kzalloc(nc->dev, struct_size(nand, cs, numcs), GFP_KERNEL);
> if (!nand) {
> dev_err(nc->dev, "Failed to allocate NAND object\n");
> return ERR_PTR(-ENOMEM);
> --
> 2.7.4
>
--
Kees Cook
Pixel Security
Hi Gustavo,
On Thu, 23 Aug 2018 20:09:38 -0500
"Gustavo A. R. Silva" <[email protected]> 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 <[email protected]>
Can we have all NAND controller drivers patched in a single patch
instead of having one patch per-driver?
Thanks,
Boris
Hi Gustavo,
"Gustavo A. R. Silva" <[email protected]> wrote on Thu, 23 Aug
2018 20:09:38 -0500:
> 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 <[email protected]>
> ---
Applied to nand/next.
Thanks,
Miquèl