2023-10-06 20:18:13

by Kees Cook

Subject: [PATCH] Input: Annotate struct ff_device with __counted_by

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct ff_device.

Cc: Dmitry Torokhov <[email protected]>
Cc: "Gustavo A. R. Silva" <[email protected]>
Cc: [email protected]
Cc: [email protected]
Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
Signed-off-by: Kees Cook <[email protected]>
---
include/linux/input.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/input.h b/include/linux/input.h
index 49790c1bd2c4..de6503c0edb8 100644
--- a/include/linux/input.h
+++ b/include/linux/input.h
@@ -562,7 +562,7 @@ struct ff_device {

int max_effects;
struct ff_effect *effects;
- struct file *effect_owners[];
+ struct file *effect_owners[] __counted_by(max_effects);
};

int input_ff_create(struct input_dev *dev, unsigned int max_effects);
--
2.34.1

2023-10-06 20:48:08

by Gustavo A. R. Silva

Subject: Re: [PATCH] Input: Annotate struct ff_device with __counted_by

On 10/6/23 22:17, Kees Cook wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
> array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
>
> As found with Coccinelle[1], add __counted_by for struct ff_device.
>
> Cc: Dmitry Torokhov <[email protected]>
> Cc: "Gustavo A. R. Silva" <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
> Signed-off-by: Kees Cook <[email protected]>

Reviewed-by: Gustavo A. R. Silva <[email protected]>

Thanks!
--
Gustavo

> ---
> include/linux/input.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/linux/input.h b/include/linux/input.h
> index 49790c1bd2c4..de6503c0edb8 100644
> --- a/include/linux/input.h
> +++ b/include/linux/input.h
> @@ -562,7 +562,7 @@ struct ff_device {
>
> int max_effects;
> struct ff_effect *effects;
> - struct file *effect_owners[];
> + struct file *effect_owners[] __counted_by(max_effects);
> };
>
> int input_ff_create(struct input_dev *dev, unsigned int max_effects);

2023-10-14 03:05:01

by Dmitry Torokhov

Subject: Re: [PATCH] Input: Annotate struct ff_device with __counted_by

On Fri, Oct 06, 2023 at 01:17:39PM -0700, Kees Cook wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
> array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
>
> As found with Coccinelle[1], add __counted_by for struct ff_device.
>
> Cc: Dmitry Torokhov <[email protected]>
> Cc: "Gustavo A. R. Silva" <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
> Signed-off-by: Kees Cook <[email protected]>

Applied, thank you.

--
Dmitry