ipx: call ipxitf_put() in ioctl error path

BugLink: http://bugs.launchpad.net/bugs/1694621

commit ee0d8d84 upstream.

We should call ipxitf_put() if the copy_to_user() fails.
Reported-by: 李强 <liqiang6-s@360.cn>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

net/ipx/af_ipx.c

@@ -1168,11 +1168,10 @@ static int ipxitf_ioctl(unsigned int cmd, void __user *arg)
 		sipx->sipx_network	= ipxif->if_netnum;
 		memcpy(sipx->sipx_node, ipxif->if_node,
 			sizeof(sipx->sipx_node));
-		rc = -EFAULT;
+		rc = 0;
 		if (copy_to_user(arg, &ifr, sizeof(ifr)))
-			break;
+			rc = -EFAULT;
 		ipxitf_put(ipxif);
-		rc = 0;
 		break;
 	}
 	case SIOCAIPXITFCRT: