From: Michael Grzeschik <m.grzeschik@pengutronix.de>
Date: Mon, 22 May 2017 13:02:44 +0200
Subject: [PATCH] usb: usbip: set buffer pointers to NULL after free
References: bnc#1060662
Patch-mainline: v4.12.1
Git-commit: b3b51417d0af63fb9a06662dc292200aed9ea53f

commit b3b51417d0af63fb9a06662dc292200aed9ea53f upstream.

The usbip stack dynamically allocates the transfer_buffer and
setup_packet of each urb that got generated by the tcp to usb stub code.
As these pointers are always used only once we will set them to NULL
after use. This is done likewise to the free_urb code in vudc_dev.c.
This patch fixes double kfree situations where the usbip remote side
added the URB_FREE_BUFFER.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Acked-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/usb/usbip/stub_main.c | 4 ++++
 drivers/usb/usbip/stub_tx.c   | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/drivers/usb/usbip/stub_main.c b/drivers/usb/usbip/stub_main.c
index 44ab43fc4fcc..af10f7b131a4 100644
--- a/drivers/usb/usbip/stub_main.c
+++ b/drivers/usb/usbip/stub_main.c
@@ -262,7 +262,11 @@ void stub_device_cleanup_urbs(struct stub_device *sdev)
 		kmem_cache_free(stub_priv_cache, priv);
 
 		kfree(urb->transfer_buffer);
+		urb->transfer_buffer = NULL;
+
 		kfree(urb->setup_packet);
+		urb->setup_packet = NULL;
+
 		usb_free_urb(urb);
 	}
 }
diff --git a/drivers/usb/usbip/stub_tx.c b/drivers/usb/usbip/stub_tx.c
index 6b1e8c3f0e4b..be50cef645d8 100644
--- a/drivers/usb/usbip/stub_tx.c
+++ b/drivers/usb/usbip/stub_tx.c
@@ -28,7 +28,11 @@ static void stub_free_priv_and_urb(struct stub_priv *priv)
 	struct urb *urb = priv->urb;
 
 	kfree(urb->setup_packet);
+	urb->setup_packet = NULL;
+
 	kfree(urb->transfer_buffer);
+	urb->transfer_buffer = NULL;
+
 	list_del(&priv->list);
 	kmem_cache_free(stub_priv_cache, priv);
 	usb_free_urb(urb);
-- 
2.14.2