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 ata_cpr_log.

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

Cc: Damien Le Moal <dlemoal@kernel.org>
Cc: linux-ide@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 include/linux/libata.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/libata.h b/include/linux/libata.h
index 3c17a5053f00..f91e8e7f1c00 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -656,7 +656,7 @@ struct ata_cpr {
 
 struct ata_cpr_log {
 	u8			nr_cpr;
-	struct ata_cpr		cpr[];
+	struct ata_cpr		cpr[] __counted_by(nr_cpr);
 };
 
 struct ata_device {
-- 
2.34.1

On 2023/09/22 19:52, 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 ata_cpr_log.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Damien Le Moal <dlemoal@kernel.org>
> Cc: linux-ide@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>

Applied to for-6.7. Thanks !

-- 
Damien Le Moal
Western Digital Research

On 9/22/23 11:52, 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 ata_cpr_log.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Damien Le Moal <dlemoal@kernel.org>
> Cc: linux-ide@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Thanks
-- 
Gustavo

> ---
>   include/linux/libata.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/linux/libata.h b/include/linux/libata.h
> index 3c17a5053f00..f91e8e7f1c00 100644
> --- a/include/linux/libata.h
> +++ b/include/linux/libata.h
> @@ -656,7 +656,7 @@ struct ata_cpr {
>   
>   struct ata_cpr_log {
>   	u8			nr_cpr;
> -	struct ata_cpr		cpr[];
> +	struct ata_cpr		cpr[] __counted_by(nr_cpr);
>   };
>   
>   struct ata_device {