From: Nobuo Iwata <nobuo.iwata@xxxxxxxxxxxxxxx>
commit d79cda045e3bacb7e754a5324cd3d4ce80708eb1 upstream.
This patch fixes possibility of dereference by NULLL pointer in "[PATCH
v5 1/3] usbip: vhci extension: modifications to vhci driver" which has
been merged to 4.9-rc1. It occurs when a URB with pointer to invalid
USB/IP device is enqueued in race condition against detach operation.
A pointer was passed to vdev_to_vhci() before NULL check.
In vdev_to_vhci(), there's a dereference by the pointer.
This patch moves vdev_to_vhci() after NULL check of the pointer.
Signed-off-by: Nobuo Iwata <nobuo.iwata@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/usbip/vhci_hcd.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/usb/usbip/vhci_hcd.c
+++ b/drivers/usb/usbip/vhci_hcd.c
@@ -465,13 +465,14 @@ static void vhci_tx_urb(struct urb *urb)
{
struct vhci_device *vdev = get_vdev(urb->dev);
struct vhci_priv *priv;
- struct vhci_hcd *vhci = vdev_to_vhci(vdev);
+ struct vhci_hcd *vhci;
unsigned long flags;
if (!vdev) {
pr_err("could not get virtual device");
return;
}
+ vhci = vdev_to_vhci(vdev);
priv = kzalloc(sizeof(struct vhci_priv), GFP_ATOMIC);
if (!priv) {
