commit ef513be0a905 ("usb: xhci: Add Clear_TT_Buffer") schedules work
to clear TT buffer, but causes a use-after-free regression at the same time
Make sure hub_tt_work finishes before endpoint is disabled, otherwise
the work will dereference already freed endpoint and device related
pointers.
This was triggered when usb core failed to read the configuration
descriptor of a FS/LS device during enumeration.
xhci driver queued clear_tt_work while usb core freed and reallocated
a new device for the next enumeration attempt.
EHCI driver implents ehci_endpoint_disable() that makes sure
clear_tt_work has finished before it returns, but xhci lacks this support.
usb core will call hcd->driver->endpoint_disable() callback before
disabling endpoints, so we want this in xhci as well.
The added xhci_endpoint_disable() is based on ehci_endpoint_disable()
Fixes: ef513be0a905 ("usb: xhci: Add Clear_TT_Buffer")
Cc: <sta...@vger.kernel.org> # v5.3
Reported-by: Johan Hovold <jo...@kernel.org>
Signed-off-by: Mathias Nyman <mathias.ny...@linux.intel.com>
---
drivers/usb/host/xhci.c | 43 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 43 insertions(+)
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 5cfbf9a04494..6e817686d04f 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -3071,6 +3071,48 @@ void xhci_cleanup_stalled_ring(struct xhci_hcd *xhci,
unsigned int ep_index,
}
}
+static void xhci_endpoint_disable(struct usb_hcd *hcd,
+ struct usb_host_endpoint *host_ep)
+{
+ struct xhci_hcd *xhci;
+ struct xhci_virt_device *vdev;
+ struct xhci_virt_ep *ep;
+ struct usb_device *udev;
+ unsigned long flags;
+ unsigned int ep_index;
+
+ xhci = hcd_to_xhci(hcd);
+rescan:
+ spin_lock_irqsave(&xhci->lock, flags);
+
+ udev = (struct usb_device *)host_ep->hcpriv;
+ if (!udev || !udev->slot_id)
+ goto done;
+
+ vdev = xhci->devs[udev->slot_id];
+ if (!vdev)
+ goto done;
+
+ ep_index = xhci_get_endpoint_index(&host_ep->desc);
+ ep = &vdev->eps[ep_index];
+ if (!ep)
+ goto done;
+
+ /* wait for hub_tt_work to finish clearing hub TT */
+ if (ep->ep_state & EP_CLEARING_TT) {
+ spin_unlock_irqrestore(&xhci->lock, flags);
+ schedule_timeout_uninterruptible(1);
+ goto rescan;
+ }
+
+ if (ep->ep_state)
+ xhci_dbg(xhci, "endpoint disable with ep_state 0x%x\n",
+ ep->ep_state);
+done:
+ host_ep->hcpriv = NULL;
+ spin_unlock_irqrestore(&xhci->lock, flags);
+}
+
/*
* Called after usb core issues a clear halt control message.
* The host side of the halt should already be cleared by a reset endpoint
@@ -5290,6 +5332,7 @@ static const struct hc_driver xhci_hc_driver = {
.free_streams = xhci_free_streams,
.add_endpoint = xhci_add_endpoint,
.drop_endpoint = xhci_drop_endpoint,
+ .endpoint_disable = xhci_endpoint_disable,
.endpoint_reset = xhci_endpoint_reset,
.check_bandwidth = xhci_check_bandwidth,
.reset_bandwidth = xhci_reset_bandwidth,
--
2.7.4
