[PATCH][next] net: spider_net: Use size_add() in call to struct_size()

[Geoff Levand]

On 9/15/23 14:25, Gustavo A. R. Silva wrote:
> If, for any reason, the open-coded arithmetic causes a wraparound,
> the protection that `struct_size()` adds against potential integer
> overflows is defeated. Fix this by hardening call to `struct_size()`
> with `size_add()`.
> 
> Fixes: 3f1071ec39f7 ("net: spider_net: Use struct_size() helper")
> Signed-off-by: Gustavo A. R. Silva <gustavoars at kernel.org>
> ---
>  drivers/net/ethernet/toshiba/spider_net.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/toshiba/spider_net.c b/drivers/net/ethernet/toshiba/spider_net.c
> index 50d7eacfec58..87e67121477c 100644
> --- a/drivers/net/ethernet/toshiba/spider_net.c
> +++ b/drivers/net/ethernet/toshiba/spider_net.c
> @@ -2332,7 +2332,7 @@ spider_net_alloc_card(void)
>  	struct spider_net_card *card;
>  
>  	netdev = alloc_etherdev(struct_size(card, darray,
> -					    tx_descriptors + rx_descriptors));
> +					    size_add(tx_descriptors, rx_descriptors)));
>  	if (!netdev)
>  		return NULL;
>  

Looks good to me.  Thanks for your fix-up.

Signed-off-by: Geoff Levand <geoff at infradead.org>