usbip: fix NULL pointer dereference on errors

Fix NULL pointer dereference and obsolete comments forgotten when
usbip server was converted from an interface driver to a device driver.
Signed-off-by: Alexander Popov <alpopov@ptsecurity.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/usbip/stub.h

@@ -33,7 +33,6 @@
 #define STUB_BUSID_ALLOC 3
 
 struct stub_device {
-	struct usb_interface *interface;
 	struct usb_device *udev;
 
 	struct usbip_device ud;

drivers/usb/usbip/stub_dev.c

@@ -219,7 +219,7 @@ static void stub_device_reset(struct usbip_device *ud)
 
 	dev_dbg(&udev->dev, "device reset");
 
-	ret = usb_lock_device_for_reset(udev, sdev->interface);
+	ret = usb_lock_device_for_reset(udev, NULL);
 	if (ret < 0) {
 		dev_err(&udev->dev, "lock for reset\n");
 		spin_lock_irq(&ud->lock);
@@ -252,7 +252,7 @@ static void stub_device_unusable(struct usbip_device *ud)
 
 /**
  * stub_device_alloc - allocate a new stub_device struct
- * @interface: usb_interface of a new device
+ * @udev: usb_device of a new device
  *
  * Allocates and initializes a new stub_device struct.
  */

drivers/usb/usbip/stub_rx.c

@@ -165,12 +165,7 @@ static int tweak_reset_device_cmd(struct urb *urb)
 
 	dev_info(&urb->dev->dev, "usb_queue_reset_device\n");
 
-	/*
-	 * With the implementation of pre_reset and post_reset the driver no
-	 * longer unbinds. This allows the use of synchronous reset.
-	 */
-
-	if (usb_lock_device_for_reset(sdev->udev, sdev->interface) < 0) {
+	if (usb_lock_device_for_reset(sdev->udev, NULL) < 0) {
 		dev_err(&urb->dev->dev, "could not obtain lock to reset device\n");
 		return 0;
 	}
@@ -321,7 +316,7 @@ static struct stub_priv *stub_priv_alloc(struct stub_device *sdev,
 
 	priv = kmem_cache_zalloc(stub_priv_cache, GFP_ATOMIC);
 	if (!priv) {
-		dev_err(&sdev->interface->dev, "alloc stub_priv\n");
+		dev_err(&sdev->udev->dev, "alloc stub_priv\n");
 		spin_unlock_irqrestore(&sdev->priv_lock, flags);
 		usbip_event_add(ud, SDEV_EVENT_ERROR_MALLOC);
 		return NULL;
@@ -352,7 +347,7 @@ static int get_pipe(struct stub_device *sdev, int epnum, int dir)
 	else
 		ep = udev->ep_out[epnum & 0x7f];
 	if (!ep) {
-		dev_err(&sdev->interface->dev, "no such endpoint?, %d\n",
+		dev_err(&sdev->udev->dev, "no such endpoint?, %d\n",
 			epnum);
 		BUG();
 	}
@@ -387,7 +382,7 @@ static int get_pipe(struct stub_device *sdev, int epnum, int dir)
 	}
 
 	/* NOT REACHED */
-	dev_err(&sdev->interface->dev, "get pipe, epnum %d\n", epnum);
+	dev_err(&sdev->udev->dev, "get pipe, epnum %d\n", epnum);
 	return 0;
 }
 
@@ -466,7 +461,7 @@ static void stub_recv_cmd_submit(struct stub_device *sdev,
 		priv->urb = usb_alloc_urb(0, GFP_KERNEL);
 
 	if (!priv->urb) {
-		dev_err(&sdev->interface->dev, "malloc urb\n");
+		dev_err(&udev->dev, "malloc urb\n");
 		usbip_event_add(ud, SDEV_EVENT_ERROR_MALLOC);
 		return;
 	}
@@ -486,7 +481,7 @@ static void stub_recv_cmd_submit(struct stub_device *sdev,
 	priv->urb->setup_packet = kmemdup(&pdu->u.cmd_submit.setup, 8,
 					  GFP_KERNEL);
 	if (!priv->urb->setup_packet) {
-		dev_err(&sdev->interface->dev, "allocate setup_packet\n");
+		dev_err(&udev->dev, "allocate setup_packet\n");
 		usbip_event_add(ud, SDEV_EVENT_ERROR_MALLOC);
 		return;
 	}
@@ -517,7 +512,7 @@ static void stub_recv_cmd_submit(struct stub_device *sdev,
 		usbip_dbg_stub_rx("submit urb ok, seqnum %u\n",
 				  pdu->base.seqnum);
 	else {
-		dev_err(&sdev->interface->dev, "submit_urb error, %d\n", ret);
+		dev_err(&udev->dev, "submit_urb error, %d\n", ret);
 		usbip_dump_header(pdu);
 		usbip_dump_urb(priv->urb);
 

drivers/usb/usbip/stub_tx.c

@@ -229,7 +229,7 @@ static int stub_send_ret_submit(struct stub_device *sdev)
 			}
 
 			if (txsize != sizeof(pdu_header) + urb->actual_length) {
-				dev_err(&sdev->interface->dev,
+				dev_err(&sdev->udev->dev,
 					"actual length of urb %d does not match iso packet sizes %zu\n",
 					urb->actual_length,
 					txsize-sizeof(pdu_header));
@@ -261,7 +261,7 @@ static int stub_send_ret_submit(struct stub_device *sdev)
 		ret = kernel_sendmsg(sdev->ud.tcp_socket, &msg,
 						iov,  iovnum, txsize);
 		if (ret != txsize) {
-			dev_err(&sdev->interface->dev,
+			dev_err(&sdev->udev->dev,
 				"sendmsg failed!, retval %d for %zd\n",
 				ret, txsize);
 			kfree(iov);
@@ -336,7 +336,7 @@ static int stub_send_ret_unlink(struct stub_device *sdev)
 		ret = kernel_sendmsg(sdev->ud.tcp_socket, &msg, iov,
 				     1, txsize);
 		if (ret != txsize) {
-			dev_err(&sdev->interface->dev,
+			dev_err(&sdev->udev->dev,
 				"sendmsg failed!, retval %d for %zd\n",
 				ret, txsize);
 			usbip_event_add(&sdev->ud, SDEV_EVENT_ERROR_TCP);