From c72a42d38b1f516b3533400a2d7ac90388b35e6c Mon Sep 17 00:00:00 2001 From: Mathias Nyman Date: Thu, 3 May 2018 17:30:07 +0300 Subject: 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: Reported-by: Guenter Roeck Reviewed-by: Guenter Roeck Tested-by: Guenter Roeck Signed-off-by: Mathias Nyman Signed-off-by: Matthias Kaehlcke Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/xhci.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index 128a3c0a9286..9dbf1583bd7a 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -3675,6 +3675,9 @@ void xhci_free_dev(struct usb_hcd *hcd, struct usb_device *udev) } spin_lock_irqsave(&xhci->lock, flags); + + virt_dev->udev = NULL; + /* Don't disable the slot if the host controller is dead. */ state = readl(&xhci->op_regs->status); if (state == 0xffffffff || (xhci->xhc_state & XHCI_STATE_DYING) || -- cgit v1.2.3