[4.2.y-ckt stable] Patch "mei: bus: check if the device is enabled before data transfer" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

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

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt7.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

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

>From a70961e817d8bdfda14dede81715f78b9b3dfee9 Mon Sep 17 00:00:00 2001
From: Alexander Usyskin <alexander.usyskin at intel.com>
Date: Sun, 7 Feb 2016 23:35:32 +0200
Subject: mei: bus: check if the device is enabled before data transfer

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