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

From: Greg Kroah-Hartman
Date: Sun Apr 10 2016 - 15:49:08 EST


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)