On 7/9/24 05:38, Oliver Neukum wrote:
At a few places the driver carries stale pointers
to references that can still be used. Make sure that does not happen.
This strictly speaking closes ZDI-CAN-22273, though there may be
similar races in the driver.
Signed-off-by: Oliver Neukum <oneukum@xxxxxxxx>
Sorry I need a bit more explanation to follow the change you
are making. Also how did you find the problem?
---
drivers/usb/usbip/vhci_hcd.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/usb/usbip/vhci_hcd.c b/drivers/usb/usbip/vhci_hcd.c
index 82650c11e451..302a89aeb258 100644
--- a/drivers/usb/usbip/vhci_hcd.c
+++ b/drivers/usb/usbip/vhci_hcd.c
@@ -745,6 +745,7 @@ static int vhci_urb_enqueue(struct usb_hcd *hcd, struct urb *urb, gfp_t mem_flag
*
*/
if (usb_pipedevice(urb->pipe) == 0) {
+ struct usb_device *old;
__u8 type = usb_pipetype(urb->pipe);
struct usb_ctrlrequest *ctrlreq =
(struct usb_ctrlrequest *) urb->setup_packet;
@@ -755,14 +756,15 @@ static int vhci_urb_enqueue(struct usb_hcd *hcd, struct urb *urb, gfp_t mem_flag
goto no_need_xmit;
}
+ old = vdev->udev;
switch (ctrlreq->bRequest) {
case USB_REQ_SET_ADDRESS:
/* set_address may come when a device is reset */
dev_info(dev, "SetAddress Request (%d) to port %d\n",
ctrlreq->wValue, vdev->rhport);
- usb_put_dev(vdev->udev);
vdev->udev = usb_get_dev(urb->dev);
+ usb_put_dev(old);
spin_lock(&vdev->ud.lock);
vdev->ud.status = VDEV_ST_USED;
@@ -781,8 +783,8 @@ static int vhci_urb_enqueue(struct usb_hcd *hcd, struct urb *urb, gfp_t mem_flag
usbip_dbg_vhci_hc(
"Not yet?:Get_Descriptor to device 0 (get max pipe size)\n");
- usb_put_dev(vdev->udev);
vdev->udev = usb_get_dev(urb->dev);
+ usb_put_dev(old);
goto out;
default:
@@ -1067,6 +1069,7 @@ static void vhci_shutdown_connection(struct usbip_device *ud)
static void vhci_device_reset(struct usbip_device *ud)
{
struct vhci_device *vdev = container_of(ud, struct vhci_device, ud);
+ struct usb_device *old = vdev->udev;
unsigned long flags;
spin_lock_irqsave(&ud->lock, flags);
@@ -1074,8 +1077,8 @@ static void vhci_device_reset(struct usbip_device *ud)
vdev->speed = 0;
vdev->devid = 0;
- usb_put_dev(vdev->udev);
vdev->udev = NULL;
+ usb_put_dev(old);
if (ud->tcp_socket) {
sockfd_put(ud->tcp_socket);
thanks,
-- Shuah
