[PATCH net 1/2] net: bridge: vlan: fix leaks on switchdev deletion errors

[Nikolay Aleksandrov <razor@blackwall.org>]

__vlan_del() stops the software deletion when the switchdev operation
fails which is ok for an explicit VLAN deletion because the VLAN remains
configured but not ok when its VLAN group is being destroyed and everything
is being freed. __vlan_flush() always destroys the VLAN group after walking
it regardless of individual deletion errors, so aborting the software vlan
delete leaks the VLAN object's memory (and potentially its master VLAN, due
to references).

Allow teardown callers to finish the software deletion while preserving
error for reporting. Save the VLAN id before deleting because the VLAN
object can already be freed (queued for freeing by call_rcu).

Fixes: 2594e9064a57 ("bridge: vlan: add per-vlan struct and move to rhashtables")
Fixes: 9c86ce2c1ae3 ("net: bridge: Notify about bridge VLANs")
Signed-off-by: Nikolay Aleksandrov <razor@blackwall.org>
---
 net/bridge/br_vlan.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c
index 1e0e436629ec..1748ea1fc202 100644
--- a/net/bridge/br_vlan.c
+++ b/net/bridge/br_vlan.c
@@ -387,7 +387,7 @@ static int __vlan_add(struct net_bridge_vlan *v, u16 flags,
 	goto out;
 }
 
-static int __vlan_del(struct net_bridge_vlan *v)
+static int __vlan_del(struct net_bridge_vlan *v, bool teardown)
 {
 	struct net_bridge_vlan *masterv = v;
 	struct net_bridge_vlan_group *vg;
@@ -405,13 +405,14 @@ static int __vlan_del(struct net_bridge_vlan *v)
 	__vlan_delete_pvid(vg, v->vid);
 	if (p) {
 		err = __vlan_vid_del(p->dev, p->br, v);
-		if (err)
+		if (err && !teardown)
 			goto out;
 	} else {
 		err = br_switchdev_port_vlan_del(v->br->dev, v->vid);
-		if (err && err != -EOPNOTSUPP)
+		if (err == -EOPNOTSUPP)
+			err = 0;
+		else if (err && !teardown)
 			goto out;
-		err = 0;
 	}
 
 	if (br_vlan_should_use(v)) {
@@ -448,7 +449,7 @@ static void __vlan_flush(const struct net_bridge *br,
 			 struct net_bridge_vlan_group *vg)
 {
 	struct net_bridge_vlan *vlan, *tmp;
-	u16 v_start = 0, v_end = 0;
+	u16 v_start = 0, v_end = 0, vid;
 	int err;
 
 	__vlan_delete_pvid(vg, vg->pvid);
@@ -463,12 +464,13 @@ static void __vlan_flush(const struct net_bridge *br,
 		}
 		v_end = vlan->vid;
 
-		err = __vlan_del(vlan);
+		vid = vlan->vid;
+		err = __vlan_del(vlan, true);
 		if (err) {
 			br_err(br,
 			       "port %u(%s) failed to delete vlan %d: %pe\n",
 			       (unsigned int) p->port_no, p->dev->name,
-			       vlan->vid, ERR_PTR(err));
+			       vid, ERR_PTR(err));
 		}
 	}
 
@@ -838,7 +840,7 @@ int br_vlan_delete(struct net_bridge *br, u16 vid)
 
 	vlan_tunnel_info_del(vg, v);
 
-	return __vlan_del(v);
+	return __vlan_del(v, false);
 }
 
 void br_vlan_flush(struct net_bridge *br)
@@ -1369,7 +1371,7 @@ int nbp_vlan_delete(struct net_bridge_port *port, u16 vid)
 	br_fdb_find_delete_local(port->br, port, port->dev->dev_addr, vid);
 	br_fdb_delete_by_port(port->br, port, vid, 0);
 
-	return __vlan_del(v);
+	return __vlan_del(v, false);
 }
 
 void nbp_vlan_flush(struct net_bridge_port *port)
-- 
2.47.3