Code:  static int rfcomm_sock_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
 {
	struct sockaddr_rc *sa = (struct sockaddr_rc *) addr;
 	struct sock *sk = sock->sk;
	int chan = sa->rc_channel;
	int err = 0;
	BT_DBG("sk %p %pMR", sk, &sa->rc_bdaddr);
 
 	if (!addr || addr->sa_family != AF_BLUETOOTH)
 		return -EINVAL;
 
 	lock_sock(sk);
 
 	if (sk->sk_state != BT_OPEN) {
		err = -EBADFD;
		goto done;
	}

	if (sk->sk_type != SOCK_STREAM) {
		err = -EINVAL;
		goto done;
	}
 
 	write_lock(&rfcomm_sk_list.lock);
 
	if (chan && __rfcomm_get_listen_sock_by_addr(chan, &sa->rc_bdaddr)) {
 		err = -EADDRINUSE;
 	} else {
 		/* Save source address */
		bacpy(&rfcomm_pi(sk)->src, &sa->rc_bdaddr);
		rfcomm_pi(sk)->channel = chan;
 		sk->sk_state = BT_BOUND;
 	}
 
	write_unlock(&rfcomm_sk_list.lock);

done:
	release_sock(sk);
	return err;
}

Commit Message: Bluetooth: Fix potential NULL dereference in RFCOMM bind callback

addr can be NULL and it should not be dereferenced before NULL checking.

Signed-off-by: Jaganath Kanakkassery <jaganath.k@samsung.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
CWE ID: CWE-476
 static int rfcomm_sock_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
 {
	struct sockaddr_rc sa;
 	struct sock *sk = sock->sk;
	int len, err = 0;
 
 	if (!addr || addr->sa_family != AF_BLUETOOTH)
 		return -EINVAL;
 
	memset(&sa, 0, sizeof(sa));
	len = min_t(unsigned int, sizeof(sa), addr_len);
	memcpy(&sa, addr, len);

	BT_DBG("sk %p %pMR", sk, &sa.rc_bdaddr);

 	lock_sock(sk);
 
 	if (sk->sk_state != BT_OPEN) {
		err = -EBADFD;
		goto done;
	}

	if (sk->sk_type != SOCK_STREAM) {
		err = -EINVAL;
		goto done;
	}
 
 	write_lock(&rfcomm_sk_list.lock);
 
	if (sa.rc_channel &&
	    __rfcomm_get_listen_sock_by_addr(sa.rc_channel, &sa.rc_bdaddr)) {
 		err = -EADDRINUSE;
 	} else {
 		/* Save source address */
		bacpy(&rfcomm_pi(sk)->src, &sa.rc_bdaddr);
		rfcomm_pi(sk)->channel = sa.rc_channel;
 		sk->sk_state = BT_BOUND;
 	}
 
	write_unlock(&rfcomm_sk_list.lock);

done:
	release_sock(sk);
	return err;
}
