Re: [PATCH 01/14] ipv4: Annotate struct fib_info with __counted_by

[Gustavo A. R. Silva]

On 9/22/23 11:28, 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 fib_info.
>
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>
> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
> Cc: David Ahern <dsahern@xxxxxxxxxx>
> Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
> Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
> Cc: Paolo Abeni <pabeni@xxxxxxxxxx>
> Cc: netdev@xxxxxxxxxxxxxxx
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>

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

Thanks
--
Gustavo

> ---
>   include/net/ip_fib.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
> index f0c13864180e..84b0a82c9df4 100644
> --- a/include/net/ip_fib.h
> +++ b/include/net/ip_fib.h
> @@ -156,7 +156,7 @@ struct fib_info {
>   	bool			nh_updated;
>   	struct nexthop		*nh;
>   	struct rcu_head		rcu;
> -	struct fib_nh		fib_nh[];
> +	struct fib_nh		fib_nh[] __counted_by(fib_nhs);
>   };
>   
>