USB: sierra: fix use after free at suspend/resume

Fix use after free or NULL-pointer dereference during suspend and
resume.

The port data may never have been allocated (port probe failed)
or may already have been released by port_remove (e.g. driver is
unloaded) when suspend and resume are called.

Fixes: e6929a9020ac ("USB: support for autosuspend in sierra while
online")

Cc: <stable@vger.kernel.org>	# v2.6.32
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/usb/serial/sierra.c b/drivers/usb/serial/sierra.c
index 07cbd985ed65..2c5c5a9330e2 100644
--- a/drivers/usb/serial/sierra.c
+++ b/drivers/usb/serial/sierra.c
@@ -933,6 +933,7 @@ static int sierra_port_remove(struct usb_serial_port *port)
         struct sierra_port_private *portdata;
 
         portdata = usb_get_serial_port_data(port);
+        usb_set_serial_port_data(port, NULL);
         kfree(portdata);
 
         return 0;
@@ -949,6 +950,8 @@ static void stop_read_write_urbs(struct usb_serial *serial)
         for (i = 0; i < serial->num_ports; ++i) {
                 port = serial->port[i];
                 portdata = usb_get_serial_port_data(port);
+                if (!portdata)
+                        continue;
                 sierra_stop_rx_urbs(port);
                 usb_kill_anchored_urbs(&portdata->active);
         }
@@ -991,6 +994,9 @@ static int sierra_resume(struct usb_serial *serial)
                 port = serial->port[i];
                 portdata = usb_get_serial_port_data(port);
 
+                if (!portdata)
+                        continue;
+
                 while ((urb = usb_get_from_anchor(&portdata->delayed))) {
                         usb_anchor_urb(urb, &portdata->active);
                         intfdata->in_flight++;