Re: [PATCH net-next V4 03/13] bridge: Validate that vlan is permitted on ingress

[Shmulik Ladkani <shmulik.ladkani@gmail.com>]

Hi Vlad,

On Wed, 19 Dec 2012 12:48:14 -0500 Vlad Yasevich <vyasevic@redhat.com> wrote:
> +static bool br_allowed_ingress(struct net_bridge_port *p, struct sk_buff *skb)
> +{
> +	struct net_port_vlan *pve;
> +	u16 vid;
> +
> +	/* If there are no vlan in the permitted list, all packets are
> +	 * permitted.
> +	 */
> +	if (list_empty(&p->vlan_list))
> +		return true;

I assumed the default policy would be Drop in such case, otherwise
leaking between vlan domains is possible.
Or maybe, ingress policy when port isn't a member of ingress VID should
be configurable (drop/allow).

> +	vid = br_get_vlan(skb);
> +	pve = nbp_vlan_find(p, vid);

Why search by iterating through NBP's vlan_list?
You know the VID (hence may fetch the net_bridge_vlan from the hash), so
why don't you directly consult the net_bridge_vlan's port_bitmap?

> @@ -54,6 +74,9 @@ int br_handle_frame_finish(struct sk_buff *skb)
>  	if (!p || p->state == BR_STATE_DISABLED)
>  		goto drop;
>  
> +	if (!br_allowed_ingress(p, skb))
> +		goto drop;
> +

This condition should be also encorporated upon "ingress" at the "bridge
master port" (that is, early at br_dev_xmit).
Think of the "bridge master port" as yet another port:
upon "ingress" (meaning, tx packets from the ip stack), we should
also enforce any ingress permission rules.

Regards,
Shmulik