This is a note to let you know that I've just added the patch titled
xhci: fix possible null pointer deref during xhci urb enqueue
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
xhci-fix-possible-null-pointer-deref-during-xhci-urb.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit e887066276129cc5b0b8350d2283dfac07c0a76f
Author: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
Date: Fri Dec 1 17:06:47 2023 +0200
xhci: fix possible null pointer deref during xhci urb enqueue
[ Upstream commit e2e2aacf042f52854c92775b7800ba668e0bdfe4 ]
There is a short gap between urb being submitted and actually added to the
endpoint queue (linked). If the device is disconnected during this time
then usb core is not yet aware of the pending urb, and device may be freed
just before xhci_urq_enqueue() continues, dereferencing the freed device.
Freeing the device is protected by the xhci spinlock, so make sure we take
and keep the lock while checking that device exists, dereference it, and
add the urb to the queue.
Remove the unnecessary URB check, usb core checks it before calling
xhci_urb_enqueue()
Suggested-by: Kuen-Han Tsai <khtsai@xxxxxxxxxx>
Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20231201150647.1307406-20-mathias.nyman@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index c02ad4f76bb3c..127fbad32a75f 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -1654,24 +1654,7 @@ static int xhci_urb_enqueue(struct usb_hcd *hcd, struct urb *urb, gfp_t mem_flag
struct urb_priv *urb_priv;
int num_tds;
- if (!urb)
- return -EINVAL;
- ret = xhci_check_args(hcd, urb->dev, urb->ep,
- true, true, __func__);
- if (ret <= 0)
- return ret ? ret : -EINVAL;
-
- slot_id = urb->dev->slot_id;
ep_index = xhci_get_endpoint_index(&urb->ep->desc);
- ep_state = &xhci->devs[slot_id]->eps[ep_index].ep_state;
-
- if (!HCD_HW_ACCESSIBLE(hcd))
- return -ESHUTDOWN;
-
- if (xhci->devs[slot_id]->flags & VDEV_PORT_ERROR) {
- xhci_dbg(xhci, "Can't queue urb, port error, link inactive\n");
- return -ENODEV;
- }
if (usb_endpoint_xfer_isoc(&urb->ep->desc))
num_tds = urb->number_of_packets;
@@ -1710,12 +1693,35 @@ static int xhci_urb_enqueue(struct usb_hcd *hcd, struct urb *urb, gfp_t mem_flag
spin_lock_irqsave(&xhci->lock, flags);
+ ret = xhci_check_args(hcd, urb->dev, urb->ep,
+ true, true, __func__);
+ if (ret <= 0) {
+ ret = ret ? ret : -EINVAL;
+ goto free_priv;
+ }
+
+ slot_id = urb->dev->slot_id;
+
+ if (!HCD_HW_ACCESSIBLE(hcd)) {
+ ret = -ESHUTDOWN;
+ goto free_priv;
+ }
+
+ if (xhci->devs[slot_id]->flags & VDEV_PORT_ERROR) {
+ xhci_dbg(xhci, "Can't queue urb, port error, link inactive\n");
+ ret = -ENODEV;
+ goto free_priv;
+ }
+
if (xhci->xhc_state & XHCI_STATE_DYING) {
xhci_dbg(xhci, "Ep 0x%x: URB %p submitted for non-responsive xHCI host.\n",
urb->ep->desc.bEndpointAddress, urb);
ret = -ESHUTDOWN;
goto free_priv;
}
+
+ ep_state = &xhci->devs[slot_id]->eps[ep_index].ep_state;
+
if (*ep_state & (EP_GETTING_STREAMS | EP_GETTING_NO_STREAMS)) {
xhci_warn(xhci, "WARN: Can't enqueue URB, ep in streams transition state %x\n",
*ep_state);
