[PATCH 4.2.y-ckt 030/218] mei: bus: check if the device is enabled before data transfer

[Kamal Mostafa]

4.2.8-ckt7 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Alexander Usyskin <alexander.usyskin at intel.com>

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 at intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler at intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/misc/mei/bus.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/misc/mei/bus.c b/drivers/misc/mei/bus.c
index 18c37af..cc867e8 100644
--- a/drivers/misc/mei/bus.c
+++ b/drivers/misc/mei/bus.c
@@ -300,6 +300,11 @@ 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;
@@ -347,6 +352,10 @@ 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)
-- 
2.7.4