llc: Check address length before reading address field

mainline inclusion
from mainline-5.1-rc6
commit c68e747d
category: bugfix
bugzilla: 14089
CVE: NA

-------------------------------------------------

KMSAN will complain if valid address length passed to bind() is shorter
than sizeof(struct sockaddr_llc) bytes.
Signed-off-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NZhiqiang Liu <liuzhiqiang26@huawei.com>
Reviewed-by: NWenan Mao <maowenan@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

net/llc/af_llc.c

@@ -320,14 +320,13 @@ static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen)
 	struct llc_sap *sap;
 	int rc = -EINVAL;
 
-	dprintk("%s: binding %02X\n", __func__, addr->sllc_sap);
-
 	lock_sock(sk);
 	if (unlikely(!sock_flag(sk, SOCK_ZAPPED) || addrlen != sizeof(*addr)))
 		goto out;
 	rc = -EAFNOSUPPORT;
 	if (unlikely(addr->sllc_family != AF_LLC))
 		goto out;
+	dprintk("%s: binding %02X\n", __func__, addr->sllc_sap);
 	rc = -ENODEV;
 	rcu_read_lock();
 	if (sk->sk_bound_dev_if) {