mei: bus: check if the device is enabled before data transfer

commit 15c13dfc upstream.

The bus data transfer interface was missing the check if the device is
in enabled state, this may lead to stack corruption during link reset.
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/bus.c

@@ -53,6 +53,11 @@ ssize_t __mei_cl_send(struct mei_cl *cl, u8 *buf, size_t length,
 	bus = cl->dev;
 
 	mutex_lock(&bus->device_lock);
+	if (bus->dev_state != MEI_DEV_ENABLED) {
+		rets = -ENODEV;
+		goto out;
+	}
+
 	if (!mei_cl_is_connected(cl)) {
 		rets = -ENODEV;
 		goto out;
@@ -109,6 +114,10 @@ ssize_t __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length)
 	bus = cl->dev;
 
 	mutex_lock(&bus->device_lock);
+	if (bus->dev_state != MEI_DEV_ENABLED) {
+		rets = -ENODEV;
+		goto out;
+	}
 
 	cb = mei_cl_read_cb(cl, NULL);
 	if (cb)