netns: read NETNSA_NSID as s32 attribute in rtnl_net_getid()

NETNSA_NSID is signed. Use nla_get_s32() to avoid confusion.
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/net_namespace.c

@@ -839,7 +839,7 @@ static int rtnl_net_getid(struct sk_buff *skb, struct nlmsghdr *nlh,
 		peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD]));
 		nla = tb[NETNSA_FD];
 	} else if (tb[NETNSA_NSID]) {
-		peer = get_net_ns_by_id(net, nla_get_u32(tb[NETNSA_NSID]));
+		peer = get_net_ns_by_id(net, nla_get_s32(tb[NETNSA_NSID]));
 		if (!peer)
 			peer = ERR_PTR(-ENOENT);
 		nla = tb[NETNSA_NSID];