[PATCH 4.4 083/210] mei: bus: check if the device is enabled before data transfer

[Greg Kroah-Hartman]

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

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

From: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>

commit 15c13dfcad883a1e76b714480fb27be96247fd82 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@xxxxxxxxx>
Signed-off-by: Tomas Winkler <tomas.winkler@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/misc/mei/bus.c |    9 +++++++++
 1 file changed, 9 insertions(+)

--- a/drivers/misc/mei/bus.c
+++ b/drivers/misc/mei/bus.c
@@ -53,6 +53,11 @@ ssize_t __mei_cl_send(struct mei_cl *cl,
 	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,
 	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)