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_KERNEL);
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_KERNEL);
Notice that, currently, there is a bug during the allocation:
sizeof(npcm7xx_clk_data) should be sizeof(*npcm7xx_clk_data)
Fix this bug by using struct_size() in kzalloc()
This issue was detected with the help of Coccinelle.
Cc: [email protected]
Signed-off-by: Gustavo A. R. Silva <[email protected]>
---
drivers/clk/clk-npcm7xx.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/clk/clk-npcm7xx.c b/drivers/clk/clk-npcm7xx.c
index 740af90..c5edf8f 100644
--- a/drivers/clk/clk-npcm7xx.c
+++ b/drivers/clk/clk-npcm7xx.c
@@ -558,8 +558,8 @@ static void __init npcm7xx_clk_init(struct device_node *clk_np)
if (!clk_base)
goto npcm7xx_init_error;
- npcm7xx_clk_data = kzalloc(sizeof(*npcm7xx_clk_data->hws) *
- NPCM7XX_NUM_CLOCKS + sizeof(npcm7xx_clk_data), GFP_KERNEL);
+ npcm7xx_clk_data = kzalloc(struct_size(npcm7xx_clk_data, hws,
+ NPCM7XX_NUM_CLOCKS), GFP_KERNEL);
if (!npcm7xx_clk_data)
goto npcm7xx_init_np_err;
--
2.7.4
On Thu, Aug 23, 2018 at 4:06 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 = kzalloc(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 = kzalloc(struct_size(instance, entry, count), GFP_KERNEL);
>
> Notice that, currently, there is a bug during the allocation:
>
> sizeof(npcm7xx_clk_data) should be sizeof(*npcm7xx_clk_data)
>
> Fix this bug by using struct_size() in kzalloc()
>
> This issue was detected with the help of Coccinelle.
>
> Cc: [email protected]
> Signed-off-by: Gustavo A. R. Silva <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
-Kees
> ---
> drivers/clk/clk-npcm7xx.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/clk/clk-npcm7xx.c b/drivers/clk/clk-npcm7xx.c
> index 740af90..c5edf8f 100644
> --- a/drivers/clk/clk-npcm7xx.c
> +++ b/drivers/clk/clk-npcm7xx.c
> @@ -558,8 +558,8 @@ static void __init npcm7xx_clk_init(struct device_node *clk_np)
> if (!clk_base)
> goto npcm7xx_init_error;
>
> - npcm7xx_clk_data = kzalloc(sizeof(*npcm7xx_clk_data->hws) *
> - NPCM7XX_NUM_CLOCKS + sizeof(npcm7xx_clk_data), GFP_KERNEL);
> + npcm7xx_clk_data = kzalloc(struct_size(npcm7xx_clk_data, hws,
> + NPCM7XX_NUM_CLOCKS), GFP_KERNEL);
> if (!npcm7xx_clk_data)
> goto npcm7xx_init_np_err;
>
> --
> 2.7.4
>
--
Kees Cook
Pixel Security
On Fri, Aug 24, 2018 at 2:18 AM Kees Cook <[email protected]> wrote:
>
> On Thu, Aug 23, 2018 at 4:06 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 = kzalloc(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 = kzalloc(struct_size(instance, entry, count), GFP_KERNEL);
> >
> > Notice that, currently, there is a bug during the allocation:
> >
> > sizeof(npcm7xx_clk_data) should be sizeof(*npcm7xx_clk_data)
> >
> > Fix this bug by using struct_size() in kzalloc()
> >
> > This issue was detected with the help of Coccinelle.
> >
> > Cc: [email protected]
> > Signed-off-by: Gustavo A. R. Silva <[email protected]>
>
> Reviewed-by: Kees Cook <[email protected]>
Reviewed-by: Avi Fishman <[email protected]>
>
> -Kees
>
> > ---
> > drivers/clk/clk-npcm7xx.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/clk/clk-npcm7xx.c b/drivers/clk/clk-npcm7xx.c
> > index 740af90..c5edf8f 100644
> > --- a/drivers/clk/clk-npcm7xx.c
> > +++ b/drivers/clk/clk-npcm7xx.c
> > @@ -558,8 +558,8 @@ static void __init npcm7xx_clk_init(struct device_node *clk_np)
> > if (!clk_base)
> > goto npcm7xx_init_error;
> >
> > - npcm7xx_clk_data = kzalloc(sizeof(*npcm7xx_clk_data->hws) *
> > - NPCM7XX_NUM_CLOCKS + sizeof(npcm7xx_clk_data), GFP_KERNEL);
> > + npcm7xx_clk_data = kzalloc(struct_size(npcm7xx_clk_data, hws,
> > + NPCM7XX_NUM_CLOCKS), GFP_KERNEL);
> > if (!npcm7xx_clk_data)
> > goto npcm7xx_init_np_err;
> >
> > --
> > 2.7.4
> >
>
>
>
> --
> Kees Cook
> Pixel Security
--
Regards,
Avi
Quoting Gustavo A. R. Silva (2018-08-23 16:06:54)
> 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_KERNEL);
>
> 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_KERNEL);
>
> Notice that, currently, there is a bug during the allocation:
>
> sizeof(npcm7xx_clk_data) should be sizeof(*npcm7xx_clk_data)
>
> Fix this bug by using struct_size() in kzalloc()
>
> This issue was detected with the help of Coccinelle.
>
> Cc: [email protected]
> Signed-off-by: Gustavo A. R. Silva <[email protected]>
> ---
Applied to clk-fixes