Re: [PATCH net 2/4] bonding: fix null pointer deref in bond_ipsec_offload_ok

[Hangbin Liu <liuhangbin@gmail.com>]

On Fri, Aug 16, 2024 at 02:48:11PM +0300, Nikolay Aleksandrov wrote:
> We must check if there is an active slave before dereferencing the pointer.
> 
> Fixes: 18cb261afd7b ("bonding: support hardware encryption offload to slaves")
> Signed-off-by: Nikolay Aleksandrov <razor@blackwall.org>
> ---
>  drivers/net/bonding/bond_main.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
> index 85b5868deeea..65ddb71eebcd 100644
> --- a/drivers/net/bonding/bond_main.c
> +++ b/drivers/net/bonding/bond_main.c
> @@ -604,6 +604,8 @@ static bool bond_ipsec_offload_ok(struct sk_buff *skb, struct xfrm_state *xs)
>  	bond = netdev_priv(bond_dev);
>  	rcu_read_lock();
>  	curr_active = rcu_dereference(bond->curr_active_slave);
> +	if (!curr_active)
> +		goto out;
>  	real_dev = curr_active->dev;
>  
>  	if (BOND_MODE(bond) != BOND_MODE_ACTIVEBACKUP)
> -- 
> 2.44.0
> 

BTW, the bond_ipsec_offload_ok() only checks !xs->xso.real_dev, should we also
add WARN_ON(xs->xso.real_dev != slave->dev) checking?

Thanks
Hangbin