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[209.132.180.67]) by mx.google.com with ESMTP id g20si3490208edb.149.2019.10.17.22.06.26; Thu, 17 Oct 2019 22:06:49 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=Wi8sHo11; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393748AbfJPWVf (ORCPT + 99 others); Wed, 16 Oct 2019 18:21:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:42500 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2437522AbfJPVxc (ORCPT ); Wed, 16 Oct 2019 17:53:32 -0400 Received: from localhost (unknown [192.55.54.58]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D2BB020872; Wed, 16 Oct 2019 21:53:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571262812; bh=N3B1XunYOvxQ2/mobggQFW4xm0jh4n0dT7C9YTzBZa4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Wi8sHo11jwIvTZkdQDsXJ+EJvcISwAS06unX1pZPdAtiGRaPC5dBCzcNUuJ54I0If W9QFmaau3KpeQe35c7HUYM89Jml1XTTdQHsk1L/p0MaN5uIKXW0Rlr0vkpfG2vvQKr fUF0Kga7mW200MdZs/xPEU+0lmPHVJq3LUswQgQk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Johan Hovold Subject: [PATCH 4.4 54/79] USB: usblcd: fix I/O after disconnect Date: Wed, 16 Oct 2019 14:50:29 -0700 Message-Id: <20191016214817.928301234@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191016214729.758892904@linuxfoundation.org> References: <20191016214729.758892904@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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") Cc: stable # 7bbe990c989e Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20190926091228.24634-7-johan@kernel.org Signed-off-by: Greg Kroah-Hartman --- 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);