usb: hcd: out of bounds access in for_each_companion

commit e86103a75705c7c530768f4ffaba74cf382910f2 upstream.

On BXT platform Host Controller and Device Controller figure as
same PCI device but with different device function. HCD should
not pass data to Device Controller but only to Host Controllers.
Checking if companion device is Host Controller, otherwise skip.

Signed-off-by: Robert Dobrowolski <robert.dobrowolski@linux.intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c
index 1f02e65fe3056e609fc0b060f4878f4f5a372598..ccdcc7063eee8ba69bcaf00003da09bc324d9665 100644 (file)
--- a/drivers/usb/core/hcd-pci.c
+++ b/drivers/usb/core/hcd-pci.c
@@ -74,6 +74,15 @@ static void for_each_companion(struct pci_dev *pdev, struct usb_hcd *hcd,
                if (companion->bus != pdev->bus ||
                                PCI_SLOT(companion->devfn) != slot)
                        continue;
+
+               /*
+                * Companion device should be either UHCI,OHCI or EHCI host
+                * controller, otherwise skip.
+                */
+               if (companion->class != CL_UHCI && companion->class != CL_OHCI &&
+                               companion->class != CL_EHCI)
+                       continue;
+
                companion_hcd = pci_get_drvdata(companion);
                if (!companion_hcd || !companion_hcd->self.root_hub)
                        continue;