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 A452FC43603 for ; Tue, 17 Dec 2019 00:58:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8239620CC7 for ; Tue, 17 Dec 2019 00:58:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728167AbfLQA6z (ORCPT ); Mon, 16 Dec 2019 19:58:55 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:34776 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726742AbfLQAvh (ORCPT ); Mon, 16 Dec 2019 19:51:37 -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 1ih15H-0003Ku-QR; Tue, 17 Dec 2019 00:51:31 +0000 Received: from ben by deadeye with local (Exim 4.93-RC7) (envelope-from ) id 1ih15H-0005W0-GT; Tue, 17 Dec 2019 00:51:31 +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 00:46:32 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 058/136] USB: yurex: fix NULL-derefs 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: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.80-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Johan Hovold commit aafb00a977cf7d81821f7c9d12e04c558c22dc3c upstream. The driver was using its struct usb_interface pointer as an inverted disconnected flag, but was setting it to NULL without making sure all code paths that used it were done with it. Before commit ef61eb43ada6 ("USB: yurex: Fix protection fault after device removal") this included the interrupt-in completion handler, but there are further accesses in dev_err and dev_dbg statements in yurex_write() and the driver-data destructor (sic!). Fix this by unconditionally stopping also the control URB at disconnect and by using a dedicated disconnected flag. Note that we need to take a reference to the struct usb_interface to avoid a use-after-free in the destructor whenever the device was disconnected while the character device was still open. Fixes: aadd6472d904 ("USB: yurex.c: remove dbg() usage") Fixes: 45714104b9e8 ("USB: yurex.c: remove err() usage") Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20191009153848.8664-6-johan@kernel.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings --- drivers/usb/misc/yurex.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) --- a/drivers/usb/misc/yurex.c +++ b/drivers/usb/misc/yurex.c @@ -64,6 +64,7 @@ struct usb_yurex { struct kref kref; struct mutex io_mutex; + unsigned long disconnected:1; struct fasync_struct *async_queue; wait_queue_head_t waitq; @@ -111,6 +112,7 @@ static void yurex_delete(struct kref *kr dev->int_buffer, dev->urb->transfer_dma); usb_free_urb(dev->urb); } + usb_put_intf(dev->interface); usb_put_dev(dev->udev); kfree(dev); } @@ -211,7 +213,7 @@ static int yurex_probe(struct usb_interf init_waitqueue_head(&dev->waitq); dev->udev = usb_get_dev(interface_to_usbdev(interface)); - dev->interface = interface; + dev->interface = usb_get_intf(interface); /* set up the endpoint information */ iface_desc = interface->cur_altsetting; @@ -334,8 +336,9 @@ static void yurex_disconnect(struct usb_ /* prevent more I/O from starting */ usb_poison_urb(dev->urb); + usb_poison_urb(dev->cntl_urb); mutex_lock(&dev->io_mutex); - dev->interface = NULL; + dev->disconnected = 1; mutex_unlock(&dev->io_mutex); /* wakeup waiters */ @@ -422,7 +425,7 @@ static ssize_t yurex_read(struct file *f dev = (struct usb_yurex *)file->private_data; mutex_lock(&dev->io_mutex); - if (!dev->interface) { /* already disconnected */ + if (dev->disconnected) { /* already disconnected */ mutex_unlock(&dev->io_mutex); return -ENODEV; } @@ -453,7 +456,7 @@ static ssize_t yurex_write(struct file * goto error; mutex_lock(&dev->io_mutex); - if (!dev->interface) { /* already disconnected */ + if (dev->disconnected) { /* already disconnected */ mutex_unlock(&dev->io_mutex); retval = -ENODEV; goto error;