From patchwork Sat Jun 16 19:25:00 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lukas Wunner X-Patchwork-Id: 930377 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-pci-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=wunner.de Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 417S4n38XWz9s37 for ; Sun, 17 Jun 2018 05:25:45 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933002AbeFPTZo (ORCPT ); Sat, 16 Jun 2018 15:25:44 -0400 Received: from mailout3.hostsharing.net ([176.9.242.54]:44687 "EHLO mailout3.hostsharing.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932542AbeFPTZn (ORCPT ); Sat, 16 Jun 2018 15:25:43 -0400 Received: from h08.hostsharing.net (h08.hostsharing.net [83.223.95.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "*.hostsharing.net", Issuer "COMODO RSA Domain Validation Secure Server CA" (not verified)) by mailout3.hostsharing.net (Postfix) with ESMTPS id 43DBB1019549A; Sat, 16 Jun 2018 21:25:42 +0200 (CEST) Received: from localhost (unknown [89.246.108.87]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by h08.hostsharing.net (Postfix) with ESMTPSA id CB21E603E110; Sat, 16 Jun 2018 21:25:41 +0200 (CEST) X-Mailbox-Line: From fdcfc1e7753648a2a3d371eed4ca4bd4972b17f6 Mon Sep 17 00:00:00 2001 Message-Id: In-Reply-To: References: From: Lukas Wunner Date: Sat, 16 Jun 2018 21:25:00 +0200 Subject: [PATCH 02/32] PCI: pciehp: Fix UAF on unplug To: Bjorn Helgaas Cc: Mika Westerberg , "Rafael J. Wysocki" , Ashok Raj , Keith Busch , Yinghai Lu , Sinan Kaya , linux-pci@vger.kernel.org Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org When pciehp is unbound (e.g. on unplug of a Thunderbolt device), the hotplug_slot struct is deregistered and thus freed before freeing the IRQ. The IRQ handler and the work items it schedules print the slot name referenced from the freed structure in various informational and debug log messages, each time resulting in a quadruple dereference of freed pointers (hotplug_slot -> pci_slot -> kobject -> name). At best the slot name is logged as "(null)", at worst kernel memory is exposed in logs or the driver crashes: pciehp 0000:10:00.0:pcie204: Slot((null)): Card not present An attacker may provoke the bug by unplugging multiple devices on a Thunderbolt daisy chain at once. Unplugging can also be simulated by powering down slots via sysfs. The bug is particularly easy to trigger in poll mode. It has been present since the driver's introduction in 2004: https://git.kernel.org/tglx/history/c/c16b4b14d980 Fix by rearranging teardown such that the IRQ is freed first. Run the work items queued by the IRQ handler to completion before freeing the hotplug_slot struct by draining the work queue from the ->release_slot callback which is invoked by pci_hp_deregister(). Cc: stable@vger.kernel.org # v2.6.4 Signed-off-by: Lukas Wunner --- drivers/pci/hotplug/pciehp.h | 1 + drivers/pci/hotplug/pciehp_core.c | 7 +++++++ drivers/pci/hotplug/pciehp_hpc.c | 4 +--- 3 files changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h index 5f892065585e..fca87a1a2b22 100644 --- a/drivers/pci/hotplug/pciehp.h +++ b/drivers/pci/hotplug/pciehp.h @@ -119,6 +119,7 @@ int pciehp_unconfigure_device(struct slot *p_slot); void pciehp_queue_pushbutton_work(struct work_struct *work); struct controller *pcie_init(struct pcie_device *dev); int pcie_init_notification(struct controller *ctrl); +void pcie_shutdown_notification(struct controller *ctrl); int pciehp_enable_slot(struct slot *p_slot); int pciehp_disable_slot(struct slot *p_slot); void pcie_reenable_notification(struct controller *ctrl); diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c index 44a6a63802d5..2ba59fc94827 100644 --- a/drivers/pci/hotplug/pciehp_core.c +++ b/drivers/pci/hotplug/pciehp_core.c @@ -62,6 +62,12 @@ static int reset_slot(struct hotplug_slot *slot, int probe); */ static void release_slot(struct hotplug_slot *hotplug_slot) { + struct slot *slot = hotplug_slot->private; + + /* queued work needs hotplug_slot name */ + cancel_delayed_work(&slot->work); + drain_workqueue(slot->wq); + kfree(hotplug_slot->ops); kfree(hotplug_slot->info); kfree(hotplug_slot); @@ -264,6 +270,7 @@ static void pciehp_remove(struct pcie_device *dev) { struct controller *ctrl = get_service_data(dev); + pcie_shutdown_notification(ctrl); cleanup_slot(ctrl); pciehp_release_ctrl(ctrl); } diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index 718b6073afad..26b85440053e 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -765,7 +765,7 @@ int pcie_init_notification(struct controller *ctrl) return 0; } -static void pcie_shutdown_notification(struct controller *ctrl) +void pcie_shutdown_notification(struct controller *ctrl) { if (ctrl->notification_enabled) { pcie_disable_notification(ctrl); @@ -800,7 +800,6 @@ static int pcie_init_slot(struct controller *ctrl) static void pcie_cleanup_slot(struct controller *ctrl) { struct slot *slot = ctrl->slot; - cancel_delayed_work(&slot->work); destroy_workqueue(slot->wq); kfree(slot); } @@ -893,7 +892,6 @@ struct controller *pcie_init(struct pcie_device *dev) void pciehp_release_ctrl(struct controller *ctrl) { - pcie_shutdown_notification(ctrl); pcie_cleanup_slot(ctrl); kfree(ctrl); }