diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h
index 14b6b3af8918..0bbaa5488423 100644
--- a/include/net/rtnetlink.h
+++ b/include/net/rtnetlink.h
@@ -64,7 +64,7 @@ struct rtnl_link_ops {
 	size_t			priv_size;
 	void			(*setup)(struct net_device *dev);
 
-	int			maxtype;
+	unsigned int		maxtype;
 	const struct nla_policy	*policy;
 	int			(*validate)(struct nlattr *tb[],
 					    struct nlattr *data[],
@@ -92,7 +92,7 @@ struct rtnl_link_ops {
 	unsigned int		(*get_num_tx_queues)(void);
 	unsigned int		(*get_num_rx_queues)(void);
 
-	int			slave_maxtype;
+	unsigned int		slave_maxtype;
 	const struct nla_policy	*slave_policy;
 	int			(*slave_changelink)(struct net_device *dev,
 						    struct net_device *slave_dev,
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 80802546c279..8ca49a0e13fb 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -59,6 +59,9 @@
 #include <net/rtnetlink.h>
 #include <net/net_namespace.h>
 
+#define RTNL_MAX_TYPE		48
+#define RTNL_SLAVE_MAX_TYPE	36
+
 struct rtnl_link {
 	rtnl_doit_func		doit;
 	rtnl_dumpit_func	dumpit;
@@ -389,6 +392,11 @@ int rtnl_link_register(struct rtnl_link_ops *ops)
 {
 	int err;
 
+	/* Sanity-check max sizes to avoid stack buffer overflow. */
+	if (WARN_ON(ops->maxtype > RTNL_MAX_TYPE ||
+		    ops->slave_maxtype > RTNL_SLAVE_MAX_TYPE))
+		return -EINVAL;
+
 	rtnl_lock();
 	err = __rtnl_link_register(ops);
 	rtnl_unlock();
@@ -2902,13 +2910,16 @@ replay:
 	}
 
 	if (1) {
-		struct nlattr *attr[ops ? ops->maxtype + 1 : 1];
-		struct nlattr *slave_attr[m_ops ? m_ops->slave_maxtype + 1 : 1];
+		struct nlattr *attr[RTNL_MAX_TYPE + 1];
+		struct nlattr *slave_attr[RTNL_SLAVE_MAX_TYPE + 1];
 		struct nlattr **data = NULL;
 		struct nlattr **slave_data = NULL;
 		struct net *dest_net, *link_net = NULL;
 
 		if (ops) {
+			if (ops->maxtype > RTNL_MAX_TYPE)
+				return -EINVAL;
+
 			if (ops->maxtype && linkinfo[IFLA_INFO_DATA]) {
 				err = nla_parse_nested(attr, ops->maxtype,
 						       linkinfo[IFLA_INFO_DATA],
@@ -2925,6 +2936,9 @@ replay:
 		}
 
 		if (m_ops) {
+			if (ops->slave_maxtype > RTNL_SLAVE_MAX_TYPE)
+				return -EINVAL;
+
 			if (m_ops->slave_maxtype &&
 			    linkinfo[IFLA_INFO_SLAVE_DATA]) {
 				err = nla_parse_nested(slave_attr,