bridge: mrp: Validate when setting the port role

This patch adds specific checks for primary(0x0) and secondary(0x1) when
setting the port role. For any other value the function
'br_mrp_set_port_role' will return -EINVAL.

Fixes: 20f6a05e ("bridge: mrp: Rework the MRP netlink interface")
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/br_mrp.c

@@ -411,10 +411,16 @@ int br_mrp_set_port_role(struct net_bridge_port *p,
 	if (!mrp)
 		return -EINVAL;
 
-	if (role == BR_MRP_PORT_ROLE_PRIMARY)
+	switch (role) {
+	case BR_MRP_PORT_ROLE_PRIMARY:
 		rcu_assign_pointer(mrp->p_port, p);
-	else
+		break;
+	case BR_MRP_PORT_ROLE_SECONDARY:
 		rcu_assign_pointer(mrp->s_port, p);
+		break;
+	default:
+		return -EINVAL;
+	}
 
 	br_mrp_port_switchdev_set_role(p, role);