[RTNETLINK]: Fix rtnetlink compat attribute patch

Sent the wrong patch previously.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/rtnetlink.h

@@ -570,12 +570,16 @@ static __inline__ int rtattr_strcmp(const struct rtattr *rta, const char *str)
 }
 
 extern int rtattr_parse(struct rtattr *tb[], int maxattr, struct rtattr *rta, int len);
-extern int rtattr_parse_nested_compat(struct rtattr *tb[], int maxattr,
-				      struct rtattr *rta, void **data, int len);
+extern int __rtattr_parse_nested_compat(struct rtattr *tb[], int maxattr,
+				        struct rtattr *rta, int len);
 
 #define rtattr_parse_nested(tb, max, rta) \
 	rtattr_parse((tb), (max), RTA_DATA((rta)), RTA_PAYLOAD((rta)))
 
+#define rtattr_parse_nested_compat(tb, max, rta, data, len) \
+({	data = RTA_PAYLOAD(rta) >= len ? RTA_DATA(rta) : NULL; \
+	__rtattr_parse_nested_compat(tb, max, rta, len); })
+
 extern int rtnetlink_send(struct sk_buff *skb, u32 pid, u32 group, int echo);
 extern int rtnl_unicast(struct sk_buff *skb, u32 pid);
 extern int rtnl_notify(struct sk_buff *skb, u32 pid, u32 group,

net/core/rtnetlink.c

@@ -97,13 +97,11 @@ int rtattr_parse(struct rtattr *tb[], int maxattr, struct rtattr *rta, int len)
 	return 0;
 }
 
-int rtattr_parse_nested_compat(struct rtattr *tb[], int maxattr,
-			       struct rtattr *rta, void **data, int len)
+int __rtattr_parse_nested_compat(struct rtattr *tb[], int maxattr,
+			         struct rtattr *rta, int len)
 {
 	if (RTA_PAYLOAD(rta) < len)
 		return -1;
-	*data = RTA_DATA(rta);
-
 	if (RTA_PAYLOAD(rta) >= RTA_ALIGN(len) + sizeof(struct rtattr)) {
 		rta = RTA_DATA(rta) + RTA_ALIGN(len);
 		return rtattr_parse_nested(tb, maxattr, rta);
@@ -1312,7 +1310,7 @@ void __init rtnetlink_init(void)
 EXPORT_SYMBOL(__rta_fill);
 EXPORT_SYMBOL(rtattr_strlcpy);
 EXPORT_SYMBOL(rtattr_parse);
-EXPORT_SYMBOL(rtattr_parse_nested_compat);
+EXPORT_SYMBOL(__rtattr_parse_nested_compat);
 EXPORT_SYMBOL(rtnetlink_put_metrics);
 EXPORT_SYMBOL(rtnl_lock);
 EXPORT_SYMBOL(rtnl_trylock);