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 ABD6AC43603 for ; Tue, 17 Dec 2019 01:00:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8B749206D3 for ; Tue, 17 Dec 2019 01:00:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727630AbfLQBAf (ORCPT ); Mon, 16 Dec 2019 20:00:35 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:34638 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726618AbfLQAvd (ORCPT ); Mon, 16 Dec 2019 19:51:33 -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-0003K7-H5; Tue, 17 Dec 2019 00:51:30 +0000 Received: from ben by deadeye with local (Exim 4.93-RC7) (envelope-from ) id 1ih15F-0005T2-VV; Tue, 17 Dec 2019 00:51:29 +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 00:45:56 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 022/136] USB: usblcd: fix I/O after 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 eb7f5a490c5edfe8126f64bc58b9ba2edef0a425 upstream. Make sure to stop all I/O on disconnect by adding a disconnected flag which is used to prevent new I/O from being started and by stopping all ongoing I/O before returning. This also fixes a potential use-after-free on driver unbind in case the driver data is freed before the completion handler has run. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20190926091228.24634-7-johan@kernel.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings --- drivers/usb/misc/usblcd.c | 33 +++++++++++++++++++++++++++++++-- 1 file changed, 31 insertions(+), 2 deletions(-) --- a/drivers/usb/misc/usblcd.c +++ b/drivers/usb/misc/usblcd.c @@ -17,6 +17,7 @@ #include #include #include +#include #include #include @@ -56,6 +57,8 @@ struct usb_lcd { using up all RAM */ struct usb_anchor submitted; /* URBs to wait for before suspend */ + struct rw_semaphore io_rwsem; + unsigned long disconnected:1; }; #define to_lcd_dev(d) container_of(d, struct usb_lcd, kref) @@ -141,6 +144,13 @@ static ssize_t lcd_read(struct file *fil dev = file->private_data; + down_read(&dev->io_rwsem); + + if (dev->disconnected) { + retval = -ENODEV; + goto out_up_io; + } + /* do a blocking bulk read to get data from the device */ retval = usb_bulk_msg(dev->udev, usb_rcvbulkpipe(dev->udev, @@ -157,6 +167,9 @@ static ssize_t lcd_read(struct file *fil retval = bytes_read; } +out_up_io: + up_read(&dev->io_rwsem); + return retval; } @@ -236,11 +249,18 @@ static ssize_t lcd_write(struct file *fi if (r < 0) return -EINTR; + down_read(&dev->io_rwsem); + + if (dev->disconnected) { + retval = -ENODEV; + goto err_up_io; + } + /* create a urb, and a buffer for it, and copy the data to the urb */ urb = usb_alloc_urb(0, GFP_KERNEL); if (!urb) { retval = -ENOMEM; - goto err_no_buf; + goto err_up_io; } buf = usb_alloc_coherent(dev->udev, count, GFP_KERNEL, @@ -277,6 +297,7 @@ static ssize_t lcd_write(struct file *fi the USB core will eventually free it entirely */ usb_free_urb(urb); + up_read(&dev->io_rwsem); exit: return count; error_unanchor: @@ -284,7 +305,8 @@ error_unanchor: error: usb_free_coherent(dev->udev, count, buf, urb->transfer_dma); usb_free_urb(urb); -err_no_buf: +err_up_io: + up_read(&dev->io_rwsem); up(&dev->limit_sem); return retval; } @@ -327,6 +349,7 @@ static int lcd_probe(struct usb_interfac } kref_init(&dev->kref); sema_init(&dev->limit_sem, USB_LCD_CONCURRENT_WRITES); + init_rwsem(&dev->io_rwsem); init_usb_anchor(&dev->submitted); dev->udev = usb_get_dev(interface_to_usbdev(interface)); @@ -437,6 +460,12 @@ static void lcd_disconnect(struct usb_in /* give back our minor */ usb_deregister_dev(interface, &lcd_class); + down_write(&dev->io_rwsem); + dev->disconnected = 1; + up_write(&dev->io_rwsem); + + usb_kill_anchored_urbs(&dev->submitted); + /* decrement our usage count */ kref_put(&dev->kref, lcd_delete);