static int nlmsg_populate_mdb_fill(struct sk_buff *skb,
				   struct net_device *dev,
				   struct br_mdb_entry *entry, u32 pid,
				   u32 seq, int type, unsigned int flags)
{
	struct nlmsghdr *nlh;
	struct br_port_msg *bpm;
	struct nlattr *nest, *nest2;

	nlh = nlmsg_put(skb, pid, seq, type, sizeof(*bpm), NLM_F_MULTI);
	if (!nlh)
		return -EMSGSIZE;

	bpm = nlmsg_data(nlh);
	memset(bpm, 0, sizeof(*bpm));
	bpm->family  = AF_BRIDGE;
	bpm->ifindex = dev->ifindex;
	nest = nla_nest_start(skb, MDBA_MDB);
	if (nest == NULL)
		goto cancel;
	nest2 = nla_nest_start(skb, MDBA_MDB_ENTRY);
	if (nest2 == NULL)
		goto end;

	if (nla_put(skb, MDBA_MDB_ENTRY_INFO, sizeof(*entry), entry))
		goto end;

	nla_nest_end(skb, nest2);
	nla_nest_end(skb, nest);
	return nlmsg_end(skb, nlh);

end:
	nla_nest_end(skb, nest);
cancel:
	nlmsg_cancel(skb, nlh);
	return -EMSGSIZE;
}

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.