From patchwork Thu Sep 19 08:30:38 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johan Hovold X-Patchwork-Id: 11151855 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id EF13776 for ; Thu, 19 Sep 2019 08:30:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CE6D5217D6 for ; Thu, 19 Sep 2019 08:30:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568881857; bh=89YVnPWhEUyNKnlCRSOysn9t6rPLNOrwjH5hCorPYSs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=2dtS5fZbABYLohYCmhk3jjypl9Ur7Op5msnj+GIiICJuGnTB0v4DlNUfsMP8cR7ek /P2vZqKw1mOZHN8Wcfim5WweFPProkauELVvIBbH9rY5zAGHS+RoSApq3xAml+/PYm FZh34QkySXOm/qWklzzc1gcDL9Qhds9QjzEEh8Xs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387856AbfISIa4 (ORCPT ); Thu, 19 Sep 2019 04:30:56 -0400 Received: from mail-lj1-f196.google.com ([209.85.208.196]:34235 "EHLO mail-lj1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387637AbfISIa4 (ORCPT ); Thu, 19 Sep 2019 04:30:56 -0400 Received: by mail-lj1-f196.google.com with SMTP id j19so1193046lja.1; Thu, 19 Sep 2019 01:30:53 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=gOw3dGTcmm1iVIPl96Li1eNYVJdVoD8Cu2D+Apy5uOg=; b=VSXQm9rq2kEK26jy2gQMIrrjT+odDFyLBS05gM1R5FiDdWS5GMoYPYmNYA/g7o6oUZ zeFQJ8h9R4C6jxm2K0yfuImkO1mFS1NtImhkFA/29TEi3zkjI8WnnmzhBb5NBpQBn1WE 9BKqZDAr7IQn9e3TEGshmvFA3zeoN5xLUf3J1pI0MTpPLeTnoq2AwtOxcLJfu9Efo4FR yW5Po6fbIOEB+kTZe40zLtRlhdBMPuEfSMKGe9MHMw6TQXUzJNJl6c2McZODB4t2VTcT ia53DhN1V2S5AmCWEMMhSJs/7pJqoFF4PpdDv3UuADO2UzEGlnhzTTUuMFUCEd6Zdl79 LTVQ== X-Gm-Message-State: APjAAAXwxM39orcJeRi0EA60QnqkNyG9A7y8ajwnCbHudnoib7A2kb/6 s8VAYyPF4+uOmWvsDpb2ejg= X-Google-Smtp-Source: APXvYqyWIQSjgHJuF5c2hJ/3S2Ghl17fi3f0cHmK25IEM9SRVN/sidVhGNKafEmPovwDTH1UmCxdHA== X-Received: by 2002:a2e:9cd3:: with SMTP id g19mr4730157ljj.150.1568881852452; Thu, 19 Sep 2019 01:30:52 -0700 (PDT) Received: from xi.terra (c-51f1e055.07-184-6d6c6d4.bbcust.telenor.se. [85.224.241.81]) by smtp.gmail.com with ESMTPSA id q19sm1636171lfj.9.2019.09.19.01.30.49 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 19 Sep 2019 01:30:50 -0700 (PDT) Received: from johan by xi.terra with local (Exim 4.92.2) (envelope-from ) id 1iArpx-00083N-Rp; Thu, 19 Sep 2019 10:30:49 +0200 From: Johan Hovold To: Greg Kroah-Hartman Cc: linux-usb@vger.kernel.org, Alan Stern , Oliver Neukum , Juergen Stuber , legousb-devel@lists.sourceforge.net, Johan Hovold , stable Subject: [PATCH RESEND 3/4] USB: legousbtower: fix potential NULL-deref on disconnect Date: Thu, 19 Sep 2019 10:30:38 +0200 Message-Id: <20190919083039.30898-4-johan@kernel.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190919083039.30898-1-johan@kernel.org> References: <20190919083039.30898-1-johan@kernel.org> MIME-Version: 1.0 Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org 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") Cc: stable # 3.5 Signed-off-by: Johan Hovold --- drivers/usb/misc/legousbtower.c | 26 +++++++++++++++----------- 1 file changed, 15 insertions(+), 11 deletions(-) diff --git a/drivers/usb/misc/legousbtower.c b/drivers/usb/misc/legousbtower.c index 773e4188f336..4fa999882635 100644 --- a/drivers/usb/misc/legousbtower.c +++ b/drivers/usb/misc/legousbtower.c @@ -190,6 +190,7 @@ 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 */ @@ -289,8 +290,6 @@ static inline void lego_usb_tower_debug_data(struct device *dev, */ 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); @@ -430,7 +429,8 @@ static int tower_release (struct inode *inode, struct file *file) 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 */ @@ -466,10 +466,9 @@ static void tower_abort_transfers (struct lego_usb_tower *dev) 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); } @@ -505,7 +504,7 @@ static __poll_t tower_poll (struct file *file, poll_table *wait) dev = file->private_data; - if (!dev->udev) + if (dev->disconnected) return EPOLLERR | EPOLLHUP; poll_wait(file, &dev->read_wait, wait); @@ -552,7 +551,7 @@ static ssize_t tower_read (struct file *file, char __user *buffer, size_t count, } /* 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; @@ -638,7 +637,7 @@ static ssize_t tower_write (struct file *file, const char __user *buffer, size_t } /* 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; @@ -748,7 +747,7 @@ static void tower_interrupt_in_callback (struct urb *urb) 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, @@ -813,6 +812,7 @@ static int tower_probe (struct usb_interface *interface, const struct usb_device dev->udev = udev; dev->open_count = 0; + dev->disconnected = 0; dev->read_buffer = NULL; dev->read_buffer_length = 0; @@ -938,6 +938,10 @@ static void tower_disconnect (struct usb_interface *interface) /* 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 */ @@ -945,7 +949,7 @@ static void tower_disconnect (struct usb_interface *interface) 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);