sctp: pass a kernel pointer to sctp_setsockopt_auto_asconf

Use the kernel pointer that sctp_setsockopt has available instead of
directly handling the user pointer.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sctp/socket.c

@@ -3807,26 +3807,23 @@ static int sctp_setsockopt_deactivate_key(struct sock *sk,
  * Note. In this implementation, socket operation overrides default parameter
  * being set by sysctl as well as FreeBSD implementation
  */
-static int sctp_setsockopt_auto_asconf(struct sock *sk, char __user *optval,
+static int sctp_setsockopt_auto_asconf(struct sock *sk, int *val,
 					unsigned int optlen)
 {
-	int val;
 	struct sctp_sock *sp = sctp_sk(sk);
 
 	if (optlen < sizeof(int))
 		return -EINVAL;
-	if (get_user(val, (int __user *)optval))
-		return -EFAULT;
-	if (!sctp_is_ep_boundall(sk) && val)
+	if (!sctp_is_ep_boundall(sk) && *val)
 		return -EINVAL;
-	if ((val && sp->do_auto_asconf) || (!val && !sp->do_auto_asconf))
+	if ((*val && sp->do_auto_asconf) || (!*val && !sp->do_auto_asconf))
 		return 0;
 
 	spin_lock_bh(&sock_net(sk)->sctp.addr_wq_lock);
-	if (val == 0 && sp->do_auto_asconf) {
+	if (*val == 0 && sp->do_auto_asconf) {
 		list_del(&sp->auto_asconf_list);
 		sp->do_auto_asconf = 0;
-	} else if (val && !sp->do_auto_asconf) {
+	} else if (*val && !sp->do_auto_asconf) {
 		list_add_tail(&sp->auto_asconf_list,
 		    &sock_net(sk)->sctp.auto_asconf_splist);
 		sp->do_auto_asconf = 1;
@@ -4690,7 +4687,7 @@ static int sctp_setsockopt(struct sock *sk, int level, int optname,
 		retval = sctp_setsockopt_deactivate_key(sk, kopt, optlen);
 		break;
 	case SCTP_AUTO_ASCONF:
-		retval = sctp_setsockopt_auto_asconf(sk, optval, optlen);
+		retval = sctp_setsockopt_auto_asconf(sk, kopt, optlen);
 		break;
 	case SCTP_PEER_ADDR_THLDS:
 		retval = sctp_setsockopt_paddr_thresholds(sk, optval, optlen,