Re: [PATCH 03/14] ipv6: Annotate struct ip6_sf_socklist 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 ip6_sf_socklist.
>
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>
> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
> 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/if_inet6.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h
> index c8490729b4ae..3e454c4d7ba6 100644
> --- a/include/net/if_inet6.h
> +++ b/include/net/if_inet6.h
> @@ -89,7 +89,7 @@ struct ip6_sf_socklist {
>   	unsigned int		sl_max;
>   	unsigned int		sl_count;
>   	struct rcu_head		rcu;
> -	struct in6_addr		sl_addr[];
> +	struct in6_addr		sl_addr[] __counted_by(sl_max);
>   };
>   
>   #define IP6_SFBLOCK	10	/* allocate this many at once */