rtnetlink: Fix an error handling path in rtnl_newlink()

When some code has been moved in the commit in Fixes, some "return err;"
have correctly been changed in goto <some_where_in_the_error_handling_path>
but this one was missed.

Should "ops->maxtype > RTNL_MAX_TYPE" happen, then some resources would
leak.

Go through the error handling path to fix these leaks.

Fixes: 0d3008d ("rtnetlink: Move ops->validate to rtnl_newlink().")
Signed-off-by: Christophe JAILLET <[email protected]>
Reviewed-by: Kuniyuki Iwashima <[email protected]>
Link: https://patch.msgid.link/eca90eeb4d9e9a0545772b68aeaab883d9fe2279.1729952228.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Jakub Kicinski <[email protected]>

Author: tititiou36

net/core/rtnetlink.c

@@ -3840,8 +3840,10 @@ static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
 	}
 
 	if (ops) {
-		if (ops->maxtype > RTNL_MAX_TYPE)
-			return -EINVAL;
+		if (ops->maxtype > RTNL_MAX_TYPE) {
+			ret = -EINVAL;
+			goto put_ops;
+		}
 
 		if (ops->maxtype && linkinfo[IFLA_INFO_DATA]) {
 			ret = nla_parse_nested_deprecated(tbs->attr, ops->maxtype,