From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 38D42C43603 for ; Tue, 17 Dec 2019 01:00:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 149D624655 for ; Tue, 17 Dec 2019 01:00:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726856AbfLQBAO (ORCPT ); Mon, 16 Dec 2019 20:00:14 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:34664 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726668AbfLQAve (ORCPT ); Mon, 16 Dec 2019 19:51:34 -0500 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1ih15G-0003KF-PD; Tue, 17 Dec 2019 00:51:30 +0000 Received: from ben by deadeye with local (Exim 4.93-RC7) (envelope-from ) id 1ih15G-0005TN-4V; Tue, 17 Dec 2019 00:51:30 +0000 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Johan Hovold" , "Greg Kroah-Hartman" Date: Tue, 17 Dec 2019 00:46:00 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 026/136] USB: legousbtower: fix potential NULL-deref on disconnect In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 3.16.80-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Johan Hovold commit cd81e6fa8e033e7bcd59415b4a65672b4780030b upstream. The driver is using its struct usb_device pointer as an inverted disconnected flag, but was setting it to NULL before making sure all completion handlers had run. This could lead to a NULL-pointer dereference in a number of dev_dbg and dev_err statements in the completion handlers which relies on said pointer. Fix this by unconditionally stopping all I/O and preventing resubmissions by poisoning the interrupt URBs at disconnect and using a dedicated disconnected flag. This also makes sure that all I/O has completed by the time the disconnect callback returns. Fixes: 9d974b2a06e3 ("USB: legousbtower.c: remove err() usage") Fixes: fef526cae700 ("USB: legousbtower: remove custom debug macro") Fixes: 4dae99638097 ("USB: legotower: remove custom debug macro and module parameter") Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20190919083039.30898-4-johan@kernel.org Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- drivers/usb/misc/legousbtower.c | 26 +++++++++++++++----------- 1 file changed, 15 insertions(+), 11 deletions(-) --- a/drivers/usb/misc/legousbtower.c +++ b/drivers/usb/misc/legousbtower.c @@ -196,6 +196,7 @@ struct lego_usb_tower { unsigned char minor; /* the starting minor number for this device */ int open_count; /* number of times this port has been opened */ + unsigned long disconnected:1; char* read_buffer; size_t read_buffer_length; /* this much came in */ @@ -295,8 +296,6 @@ static inline void lego_usb_tower_debug_ */ static inline void tower_delete (struct lego_usb_tower *dev) { - tower_abort_transfers (dev); - /* free data structures */ usb_free_urb(dev->interrupt_in_urb); usb_free_urb(dev->interrupt_out_urb); @@ -436,7 +435,8 @@ static int tower_release (struct inode * retval = -ENODEV; goto unlock_exit; } - if (dev->udev == NULL) { + + if (dev->disconnected) { /* the device was unplugged before the file was released */ /* unlock here as tower_delete frees dev */ @@ -472,10 +472,9 @@ static void tower_abort_transfers (struc if (dev->interrupt_in_running) { dev->interrupt_in_running = 0; mb(); - if (dev->udev) - usb_kill_urb (dev->interrupt_in_urb); + usb_kill_urb(dev->interrupt_in_urb); } - if (dev->interrupt_out_busy && dev->udev) + if (dev->interrupt_out_busy) usb_kill_urb(dev->interrupt_out_urb); } @@ -511,7 +510,7 @@ static unsigned int tower_poll (struct f dev = file->private_data; - if (!dev->udev) + if (dev->disconnected) return POLLERR | POLLHUP; poll_wait(file, &dev->read_wait, wait); @@ -558,7 +557,7 @@ static ssize_t tower_read (struct file * } /* verify that the device wasn't unplugged */ - if (dev->udev == NULL) { + if (dev->disconnected) { retval = -ENODEV; pr_err("No device or device unplugged %d\n", retval); goto unlock_exit; @@ -644,7 +643,7 @@ static ssize_t tower_write (struct file } /* verify that the device wasn't unplugged */ - if (dev->udev == NULL) { + if (dev->disconnected) { retval = -ENODEV; pr_err("No device or device unplugged %d\n", retval); goto unlock_exit; @@ -753,7 +752,7 @@ static void tower_interrupt_in_callback resubmit: /* resubmit if we're still running */ - if (dev->interrupt_in_running && dev->udev) { + if (dev->interrupt_in_running) { retval = usb_submit_urb (dev->interrupt_in_urb, GFP_ATOMIC); if (retval) dev_err(&dev->udev->dev, @@ -823,6 +822,7 @@ static int tower_probe (struct usb_inter dev->udev = udev; dev->open_count = 0; + dev->disconnected = 0; dev->read_buffer = NULL; dev->read_buffer_length = 0; @@ -970,6 +970,10 @@ static void tower_disconnect (struct usb /* give back our minor and prevent further open() */ usb_deregister_dev (interface, &tower_class); + /* stop I/O */ + usb_poison_urb(dev->interrupt_in_urb); + usb_poison_urb(dev->interrupt_out_urb); + mutex_lock(&dev->lock); /* if the device is not opened, then we clean up right now */ @@ -977,7 +981,7 @@ static void tower_disconnect (struct usb mutex_unlock(&dev->lock); tower_delete (dev); } else { - dev->udev = NULL; + dev->disconnected = 1; /* wake up pollers */ wake_up_interruptible_all(&dev->read_wait); wake_up_interruptible_all(&dev->write_wait);