USB: pl2303: fix port-data memory leak

Fix port-data memory leak by allocating and freeing port data in
port_probe/remove rather than in attach/release, and by introducing
serial private data to store the device type which is interface rather
than port specific.

Since commit 0998d063 (device-core: Ensure drvdata = NULL when no
driver is bound) the port private data is no longer freed at release.

Cc: <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/serial/pl2303.c

@@ -133,12 +133,15 @@ enum pl2303_type {
 	HX,		/* HX version of the pl2303 chip */
 };
 
+struct pl2303_serial_private {
+	enum pl2303_type type;
+};
+
 struct pl2303_private {
 	spinlock_t lock;
 	wait_queue_head_t delta_msr_wait;
 	u8 line_control;
 	u8 line_status;
-	enum pl2303_type type;
 };
 
 static int pl2303_vendor_read(__u16 value, __u16 index,
@@ -167,14 +170,19 @@ static int pl2303_vendor_write(__u16 value, __u16 index,
 
 static int pl2303_startup(struct usb_serial *serial)
 {
-	struct pl2303_private *priv;
+	struct pl2303_serial_private *spriv;
 	enum pl2303_type type = type_0;
 	unsigned char *buf;
-	int i;
+
+	spriv = kzalloc(sizeof(*spriv), GFP_KERNEL);
+	if (!spriv)
+		return -ENOMEM;
 
 	buf = kmalloc(10, GFP_KERNEL);
-	if (buf == NULL)
+	if (!buf) {
+		kfree(spriv);
 		return -ENOMEM;
+	}
 
 	if (serial->dev->descriptor.bDeviceClass == 0x02)
 		type = type_0;
@@ -186,15 +194,8 @@ static int pl2303_startup(struct usb_serial *serial)
 		type = type_1;
 	dev_dbg(&serial->interface->dev, "device type: %d\n", type);
 
-	for (i = 0; i < serial->num_ports; ++i) {
-		priv = kzalloc(sizeof(struct pl2303_private), GFP_KERNEL);
-		if (!priv)
-			goto cleanup;
-		spin_lock_init(&priv->lock);
-		init_waitqueue_head(&priv->delta_msr_wait);
-		priv->type = type;
-		usb_set_serial_port_data(serial->port[i], priv);
-	}
+	spriv->type = type;
+	usb_set_serial_data(serial, spriv);
 
 	pl2303_vendor_read(0x8484, 0, serial, buf);
 	pl2303_vendor_write(0x0404, 0, serial);
@@ -213,15 +214,40 @@ static int pl2303_startup(struct usb_serial *serial)
 
 	kfree(buf);
 	return 0;
+}
 
-cleanup:
-	kfree(buf);
-	for (--i; i >= 0; --i) {
-		priv = usb_get_serial_port_data(serial->port[i]);
-		kfree(priv);
-		usb_set_serial_port_data(serial->port[i], NULL);
-	}
+static void pl2303_release(struct usb_serial *serial)
+{
+	struct pl2303_serial_private *spriv;
+
+	spriv = usb_get_serial_data(serial);
+	kfree(spriv);
+}
+
+static int pl2303_port_probe(struct usb_serial_port *port)
+{
+	struct pl2303_private *priv;
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv)
 		return -ENOMEM;
+
+	spin_lock_init(&priv->lock);
+	init_waitqueue_head(&priv->delta_msr_wait);
+
+	usb_set_serial_port_data(port, priv);
+
+	return 0;
+}
+
+static int pl2303_port_remove(struct usb_serial_port *port)
+{
+	struct pl2303_private *priv;
+
+	priv = usb_get_serial_port_data(port);
+	kfree(priv);
+
+	return 0;
 }
 
 static int set_control_lines(struct usb_device *dev, u8 value)
@@ -240,6 +266,7 @@ static void pl2303_set_termios(struct tty_struct *tty,
 		struct usb_serial_port *port, struct ktermios *old_termios)
 {
 	struct usb_serial *serial = port->serial;
+	struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
 	struct pl2303_private *priv = usb_get_serial_port_data(port);
 	unsigned long flags;
 	unsigned int cflag;
@@ -323,7 +350,7 @@ static void pl2303_set_termios(struct tty_struct *tty,
 		}
 		if (baud > 1228800) {
 			/* type_0, type_1 only support up to 1228800 baud */
-			if (priv->type != HX)
+			if (spriv->type != HX)
 				baud = 1228800;
 			else if (baud > 6000000)
 				baud = 6000000;
@@ -426,7 +453,7 @@ static void pl2303_set_termios(struct tty_struct *tty,
 	     buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], buf[6]);
 
 	if (cflag & CRTSCTS) {
-		if (priv->type == HX)
+		if (spriv->type == HX)
 			pl2303_vendor_write(0x0, 0x61, serial);
 		else
 			pl2303_vendor_write(0x0, 0x41, serial);
@@ -468,10 +495,10 @@ static int pl2303_open(struct tty_struct *tty, struct usb_serial_port *port)
 {
 	struct ktermios tmp_termios;
 	struct usb_serial *serial = port->serial;
-	struct pl2303_private *priv = usb_get_serial_port_data(port);
+	struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
 	int result;
 
-	if (priv->type != HX) {
+	if (spriv->type != HX) {
 		usb_clear_halt(serial->dev, port->write_urb->pipe);
 		usb_clear_halt(serial->dev, port->read_urb->pipe);
 	} else {
@@ -655,17 +682,6 @@ static void pl2303_break_ctl(struct tty_struct *tty, int break_state)
 		dev_err(&port->dev, "error sending break = %d\n", result);
 }
 
-static void pl2303_release(struct usb_serial *serial)
-{
-	int i;
-	struct pl2303_private *priv;
-
-	for (i = 0; i < serial->num_ports; ++i) {
-		priv = usb_get_serial_port_data(serial->port[i]);
-		kfree(priv);
-	}
-}
-
 static void pl2303_update_line_status(struct usb_serial_port *port,
 				      unsigned char *data,
 				      unsigned int actual_length)
@@ -827,6 +843,8 @@ static struct usb_serial_driver pl2303_device = {
 	.read_int_callback =	pl2303_read_int_callback,
 	.attach =		pl2303_startup,
 	.release =		pl2303_release,
+	.port_probe =		pl2303_port_probe,
+	.port_remove =		pl2303_port_remove,
 };
 
 static struct usb_serial_driver * const serial_drivers[] = {