From 44a182b9d17765514fa2b1cc911e4e65134eef93 Mon Sep 17 00:00:00 2001
From: Mathias Nyman <mathias.nyman@linux.intel.com>
Date: Thu, 3 May 2018 17:30:07 +0300
Subject: [PATCH] xhci: Fix use-after-free in xhci_free_virt_device
Git-commit: 44a182b9d17765514fa2b1cc911e4e65134eef93
Patch-mainline: v4.17-rc4
References: bsc#1100132
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
drivers/usb/host/xhci.c | 1 +
1 file changed, 1 insertion(+)
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -3551,6 +3551,7 @@ static void xhci_free_dev(struct usb_hcd
del_timer_sync(&virt_dev->eps[i].stop_cmd_timer);
}
+ virt_dev->udev = NULL;
xhci_disable_slot(xhci, udev->slot_id);
/*
* Event command completion handler will free any data structures