linux-kernel - [ 59/72] USB: cdc-acm: fix device unregistration

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20130326224925.778059073@linuxfoundation.org>
Date:	Tue, 26 Mar 2013 15:51:42 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, Oliver Neukum <oneukum@...e.de>,
	Johan Hovold <jhovold@...il.com>
Subject: [ 59/72] USB: cdc-acm: fix device unregistration

3.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Johan Hovold <jhovold@...il.com>

commit cb25505fc604292c70fc02143fc102f54c8595f0 upstream.

Unregister tty device in disconnect as is required by the USB stack.

By deferring unregistration to when the last tty reference is dropped,
the parent interface device can get unregistered before the child
resulting in broken hotplug events being generated when the tty is
finally closed:

KERNEL[2290.798128] remove   /devices/pci0000:00/0000:00:1d.7/usb2/2-1/2-1:3.1 (usb)
KERNEL[2290.804589] remove   /devices/pci0000:00/0000:00:1d.7/usb2/2-1 (usb)
KERNEL[2294.554799] remove   /2-1:3.1/tty/ttyACM0 (tty)

The driver must deal with tty callbacks after disconnect by checking the
disconnected flag. Specifically, further opens must be prevented and
this is already implemented.

Acked-by: Oliver Neukum <oneukum@...e.de>
Cc: Oliver Neukum <oneukum@...e.de>
Signed-off-by: Johan Hovold <jhovold@...il.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/usb/class/cdc-acm.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -601,7 +601,6 @@ static void acm_port_destruct(struct tty
 
 	dev_dbg(&acm->control->dev, "%s\n", __func__);
 
-	tty_unregister_device(acm_tty_driver, acm->minor);
 	acm_release_minor(acm);
 	usb_put_intf(acm->control);
 	kfree(acm->country_codes);
@@ -1418,6 +1417,8 @@ static void acm_disconnect(struct usb_in
 
 	stop_data_traffic(acm);
 
+	tty_unregister_device(acm_tty_driver, acm->minor);
+
 	usb_free_urb(acm->ctrlurb);
 	for (i = 0; i < ACM_NW; i++)
 		usb_free_urb(acm->wb[i].urb);


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/