usb: hcd: out of bounds access in for_each_companion

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.

Cc: <stable@vger.kernel.org>
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 f9d42cf23e55f80104066f6c38b6deda9943f458..7859d738df418f5c3447a8f524d4d8a922299299 100644 (file)
--- a/drivers/usb/core/hcd-pci.c
+++ b/drivers/usb/core/hcd-pci.c
@@ -73,6 +73,15 @@ 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;