xhci: Fix use-after-free in xhci_free_virt_device
authorMathias Nyman <mathias.nyman@linux.intel.com>
Thu, 3 May 2018 14:30:07 +0000 (17:30 +0300)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 3 Jul 2018 09:25:05 +0000 (11:25 +0200)
commit4798e96b7646d562f839b9a87332d86a5aa5bf10
tree1018a523b6e6b37d0e78d46bb7d1778eec27c8fd
parent0b19825ffa2838c7a3eaa83851dc19e8d5c527b3
xhci: Fix use-after-free in xhci_free_virt_device

commit 44a182b9d17765514fa2b1cc911e4e65134eef93 upstream.

KASAN found a use-after-free in xhci_free_virt_device+0x33b/0x38e
where xhci_free_virt_device() sets slot id to 0 if udev exists:
if (dev->udev && dev->udev->slot_id)
dev->udev->slot_id = 0;

dev->udev will be true even if udev is freed because dev->udev is
not set to NULL.

set dev->udev pointer to NULL in xhci_free_dev()

The original patch went to stable so this fix needs to be applied
there as well.

Fixes: a400efe455f7 ("xhci: zero usb device slot_id member when disabling and freeing a xhci slot")
Cc: <stable@vger.kernel.org>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/usb/host/xhci.c