[4.2.y-ckt stable] Patch "usb: hcd: out of bounds access in for_each_companion" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    usb: hcd: out of bounds access in for_each_companion

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt9.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From 97b9dbe116fda21a2e298c189eebb9db286cb849 Mon Sep 17 00:00:00 2001
From: Robert Dobrowolski <robert.dobrowolski at linux.intel.com>
Date: Thu, 24 Mar 2016 03:30:07 -0700
Subject: 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 at linux.intel.com>
Acked-by: Alan Stern <stern at rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/usb/core/hcd-pci.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c
index 9eb1cff..b8b580e 100644
--- 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;
--
2.7.4