2023-09-16 03:21:25

by Kees Cook

Subject: [PATCH] leds: aw200xx: Annotate struct aw200xx 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 checking 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 aw200xx.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: Pavel Machek <[email protected]>
Cc: Lee Jones <[email protected]>
Cc: [email protected]
Signed-off-by: Kees Cook <[email protected]>
---
drivers/leds/leds-aw200xx.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/leds/leds-aw200xx.c b/drivers/leds/leds-aw200xx.c
index 691a743cc9b0..4d517cace3e7 100644
--- a/drivers/leds/leds-aw200xx.c
+++ b/drivers/leds/leds-aw200xx.c
@@ -112,7 +112,7 @@ struct aw200xx {
struct mutex mutex;
u32 num_leds;
u32 display_rows;
- struct aw200xx_led leds[];
+ struct aw200xx_led leds[] __counted_by(num_leds);
};

static ssize_t dim_show(struct device *dev, struct device_attribute *devattr,
--
2.34.1

2023-09-20 13:49:03

by Lee Jones

Subject: Re: (subset) [PATCH] leds: aw200xx: Annotate struct aw200xx with __counted_by

On Fri, 15 Sep 2023 13:09:39 -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 checking 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 aw200xx.
>
> [...]

Applied, thanks!

[1/1] leds: aw200xx: Annotate struct aw200xx with __counted_by
commit: e43d6b679091d196d9ac7664035155ed4c9637cc

--
Lee Jones [李琼斯]