Commit 36c92936 authored by Nikolay Aleksandrov's avatar Nikolay Aleksandrov Committed by Jakub Kicinski
Browse files

net: bridge: mst: pass vlan group directly to br_mst_vlan_set_state 



Pass the already obtained vlan group pointer to br_mst_vlan_set_state()
instead of dereferencing it again. Each caller has already correctly
dereferenced it for their context. This change is required for the
following suspicious RCU dereference fix. No functional changes
intended.

Fixes: 3a7c1661 ("net: bridge: mst: fix vlan use-after-free")
Reported-by: default avatar <syzbot+9bbe2de1bc9d470eb5fe@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=9bbe2de1bc9d470eb5fe


Signed-off-by: default avatarNikolay Aleksandrov <razor@blackwall.org>
Link: https://lore.kernel.org/r/20240609103654.914987-2-razor@blackwall.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 14a20e5b

net/bridge/br_mst.c

+5 −6
Original line number Diff line number Diff line
@@ -73,11 +73,10 @@ int br_mst_get_state(const struct net_device *dev, u16 msti, u8 *state) 
}

EXPORT_SYMBOL_GPL(br_mst_get_state);



static void br_mst_vlan_set_state(struct net_bridge_port *p, struct net_bridge_vlan *v,

static void br_mst_vlan_set_state(struct net_bridge_vlan_group *vg,

				  struct net_bridge_vlan *v,

				  u8 state)

{

	struct net_bridge_vlan_group *vg = nbp_vlan_group(p);



	if (br_vlan_get_state(v) == state)

		return;
@@ -121,7 +120,7 @@ int br_mst_set_state(struct net_bridge_port *p, u16 msti, u8 state, 
		if (v->brvlan->msti != msti)

			continue;



		br_mst_vlan_set_state(p, v, state);

		br_mst_vlan_set_state(vg, v, state);

	}



out:
@@ -140,13 +139,13 @@ static void br_mst_vlan_sync_state(struct net_bridge_vlan *pv, u16 msti) 
		 * it.

		 */

		if (v != pv && v->brvlan->msti == msti) {

			br_mst_vlan_set_state(pv->port, pv, v->state);

			br_mst_vlan_set_state(vg, pv, v->state);

			return;

		}

	}



	/* Otherwise, start out in a new MSTI with all ports disabled. */

	return br_mst_vlan_set_state(pv->port, pv, BR_STATE_DISABLED);

	return br_mst_vlan_set_state(vg, pv, BR_STATE_DISABLED);

}



int br_mst_vlan_set_msti(struct net_bridge_vlan *mv, u16 msti)