2023-09-15 23:15:58

by Kees Cook

Subject: [PATCH] leds: lm3697: Annotate struct lm3697 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 lm3697.

[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-lm3697.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/leds/leds-lm3697.c b/drivers/leds/leds-lm3697.c
index cfb8ac220db6..380d17a58fe9 100644
--- a/drivers/leds/leds-lm3697.c
+++ b/drivers/leds/leds-lm3697.c
@@ -89,7 +89,7 @@ struct lm3697 {
int bank_cfg;
int num_banks;

- struct lm3697_led leds[];
+ struct lm3697_led leds[] __counted_by(num_banks);
};

static const struct reg_default lm3697_reg_defs[] = {
--
2.34.1

2023-09-20 13:49:35

by Lee Jones

Subject: Re: (subset) [PATCH] leds: lm3697: Annotate struct lm3697 with __counted_by

On Fri, 15 Sep 2023 13:10:10 -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 lm3697.
>
> [...]

Applied, thanks!

[1/1] leds: lm3697: Annotate struct lm3697 with __counted_by
commit: 1a210f7d060854f541be9a613bf942849fd5c0b5

--
Lee Jones [李琼斯]