Re: [PATCH net 3/5] macsec: fix secy->n_rx_sc accounting

[Leon Romanovsky <leon@kernel.org>]

On Thu, Oct 13, 2022 at 04:15:41PM +0200, Sabrina Dubroca wrote:
> secy->n_rx_sc is supposed to be the number of _active_ rxsc's within a
> secy. This is then used by macsec_send_sci to help decide if we should
> add the SCI to the header or not.
> 
> This logic is currently broken when we create a new RXSC and turn it
> off at creation, as create_rx_sc always sets ->active to true (and
> immediately uses that to increment n_rx_sc), and only later
> macsec_add_rxsc sets rx_sc->active.
> 
> Fixes: c09440f7dcb3 ("macsec: introduce IEEE 802.1AE driver")
> Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
> ---
>  drivers/net/macsec.c | 15 +++++++++------
>  1 file changed, 9 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c
> index 0d6fe34b91ae..cdee342e42cd 100644
> --- a/drivers/net/macsec.c
> +++ b/drivers/net/macsec.c
> @@ -1413,7 +1413,8 @@ static struct macsec_rx_sc *del_rx_sc(struct macsec_secy *secy, sci_t sci)
>  	return NULL;
>  }
>  
> -static struct macsec_rx_sc *create_rx_sc(struct net_device *dev, sci_t sci)
> +static struct macsec_rx_sc *create_rx_sc(struct net_device *dev, sci_t sci,
> +					 bool active)
>  {
>  	struct macsec_rx_sc *rx_sc;
>  	struct macsec_dev *macsec;
> @@ -1437,7 +1438,7 @@ static struct macsec_rx_sc *create_rx_sc(struct net_device *dev, sci_t sci)
>  	}
>  
>  	rx_sc->sci = sci;
> -	rx_sc->active = true;
> +	rx_sc->active = active;
>  	refcount_set(&rx_sc->refcnt, 1);
>  
>  	secy = &macsec_priv(dev)->secy;
> @@ -1876,6 +1877,7 @@ static int macsec_add_rxsc(struct sk_buff *skb, struct genl_info *info)
>  	struct macsec_rx_sc *rx_sc;
>  	struct nlattr *tb_rxsc[MACSEC_RXSC_ATTR_MAX + 1];
>  	struct macsec_secy *secy;
> +	bool active = true;
>  	int ret;
>  
>  	if (!attrs[MACSEC_ATTR_IFINDEX])
> @@ -1897,15 +1899,16 @@ static int macsec_add_rxsc(struct sk_buff *skb, struct genl_info *info)
>  	secy = &macsec_priv(dev)->secy;
>  	sci = nla_get_sci(tb_rxsc[MACSEC_RXSC_ATTR_SCI]);
>  
> -	rx_sc = create_rx_sc(dev, sci);
> +
> +	if (tb_rxsc[MACSEC_RXSC_ATTR_ACTIVE])
> +		active = !!nla_get_u8(tb_rxsc[MACSEC_RXSC_ATTR_ACTIVE]);

You don't need !! to assign to bool variables and can safely omit them.

thanks

> +
> +	rx_sc = create_rx_sc(dev, sci, active);
>  	if (IS_ERR(rx_sc)) {
>  		rtnl_unlock();
>  		return PTR_ERR(rx_sc);
>  	}
>  
> -	if (tb_rxsc[MACSEC_RXSC_ATTR_ACTIVE])
> -		rx_sc->active = !!nla_get_u8(tb_rxsc[MACSEC_RXSC_ATTR_ACTIVE]);
> -
>  	if (macsec_is_offloaded(netdev_priv(dev))) {
>  		const struct macsec_ops *ops;
>  		struct macsec_context ctx;
> -- 
> 2.38.0
>