From patchwork Mon May 14 08:57:23 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mathias Nyman X-Patchwork-Id: 10397511 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 0A1F4600D0 for ; Mon, 14 May 2018 08:55:15 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F012128736 for ; Mon, 14 May 2018 08:55:14 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E31D128EB6; Mon, 14 May 2018 08:55:14 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 61E1028736 for ; Mon, 14 May 2018 08:55:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752042AbeENIzL (ORCPT ); Mon, 14 May 2018 04:55:11 -0400 Received: from mga12.intel.com ([192.55.52.136]:5389 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752020AbeENIzK (ORCPT ); Mon, 14 May 2018 04:55:10 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 14 May 2018 01:55:10 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.49,399,1520924400"; d="scan'208";a="54954812" Received: from mattu-haswell.fi.intel.com ([10.237.72.164]) by fmsmga001.fm.intel.com with ESMTP; 14 May 2018 01:55:08 -0700 From: Mathias Nyman To: Cc: , Mathias Nyman , stable@vger.kernel.org Subject: [PATCH 1/1] xhci: Fix USB3 NULL pointer dereference at logical disconnect. Date: Mon, 14 May 2018 11:57:23 +0300 Message-Id: <1526288243-6137-2-git-send-email-mathias.nyman@linux.intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1526288243-6137-1-git-send-email-mathias.nyman@linux.intel.com> References: <1526288243-6137-1-git-send-email-mathias.nyman@linux.intel.com> Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Hub driver will try to disable a USB3 device twice at logical disconnect, racing with xhci_free_dev() callback from the first port disable. This can be triggered with "udisksctl power-off --block-device " or by writing "1" to the "remove" sysfs file for a USB3 device in 4.17-rc4. USB3 devices don't have a similar disabled link state as USB2 devices, and use a U3 suspended link state instead. In this state the port is still enabled and connected. hub_port_connect() first disconnects the device, then later it notices that device is still enabled (due to U3 states) it will try to disable the port again (set to U3). The xhci_free_dev() called during device disable is async, so checking for existing xhci->devs[i] when setting link state to U3 the second time was successful, even if device was being freed. The regression was caused by, and whole thing revealed by, Commit 44a182b9d177 ("xhci: Fix use-after-free in xhci_free_virt_device") which sets xhci->devs[i]->udev to NULL before xhci_virt_dev() returned. and causes a NULL pointer dereference the second time we try to set U3. Fix this by checking xhci->devs[i]->udev exists before setting link state. The original patch went to stable so this fix needs to be applied there as well. Fixes: 44a182b9d177 ("xhci: Fix use-after-free in xhci_free_virt_device") Cc: Reported-by: Jordan Glover Tested-by: Jordan Glover Signed-off-by: Mathias Nyman --- drivers/usb/host/xhci-hub.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c index 72ebbc9..32cd52c 100644 --- a/drivers/usb/host/xhci-hub.c +++ b/drivers/usb/host/xhci-hub.c @@ -354,7 +354,7 @@ int xhci_find_slot_id_by_port(struct usb_hcd *hcd, struct xhci_hcd *xhci, slot_id = 0; for (i = 0; i < MAX_HC_SLOTS; i++) { - if (!xhci->devs[i]) + if (!xhci->devs[i] || !xhci->devs[i]->udev) continue; speed = xhci->devs[i]->udev->speed; if (((speed >= USB_SPEED_SUPER) == (hcd->speed >= HCD_USB3))