Re: [PATCH] flow_offload: Annotate struct flow_action_entry with __counted_by

["Gustavo A. R. Silva" <gustavo@embeddedor.com>]

On 10/4/23 01:18, 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 flow_action_entry.
> 
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: netdev@vger.kernel.org
> Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
> Signed-off-by: Kees Cook <keescook@chromium.org>

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

Thanks
--
Gustavo

> ---
>   include/net/flow_offload.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/net/flow_offload.h b/include/net/flow_offload.h
> index 9efa9a59e81f..314087a5e181 100644
> --- a/include/net/flow_offload.h
> +++ b/include/net/flow_offload.h
> @@ -333,7 +333,7 @@ struct flow_action_entry {
>   
>   struct flow_action {
>   	unsigned int			num_entries;
> -	struct flow_action_entry	entries[];
> +	struct flow_action_entry	entries[] __counted_by(num_entries);
>   };
>   
>   static inline bool flow_action_has_entries(const struct flow_action *action)