Re: [PATCH] landlock: Annotate struct landlock_rule with __counted_by

[Gustavo A. R. Silva]

On 8/17/23 15:03, 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 landlock_rule.
>
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>
> Cc: "Mickaël Salaün" <mic@xxxxxxxxxxx>
> Cc: Paul Moore <paul@xxxxxxxxxxxxxx>
> Cc: James Morris <jmorris@xxxxxxxxx>
> Cc: "Serge E. Hallyn" <serge@xxxxxxxxxx>
> Cc: linux-security-module@xxxxxxxxxxxxxxx
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>

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

Thanks
--
Gustavo

> ---
>   security/landlock/ruleset.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h
> index d43231b783e4..55b1df8f66a8 100644
> --- a/security/landlock/ruleset.h
> +++ b/security/landlock/ruleset.h
> @@ -67,7 +67,7 @@ struct landlock_rule {
>   	 * @layers: Stack of layers, from the latest to the newest, implemented
>   	 * as a flexible array member (FAM).
>   	 */
> -	struct landlock_layer layers[];
> +	struct landlock_layer layers[] __counted_by(num_layers);
>   };
>   
>   /**