Patch "mei: validate request value in client notify request ioctl" has been added to the 4.4-stable tree

Patch "mei: validate request value in client notify request ioctl" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    mei: validate request value in client notify request ioctl

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mei-validate-request-value-in-client-notify-request-ioctl.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 7326fffb712f09a315bc73cc1ee63843f59b8bd4 Mon Sep 17 00:00:00 2001
From: Alexander Usyskin <alexander.usyskin@intel.com>
Date: Sun, 17 Jan 2016 12:25:01 +0200
Subject: mei: validate request value in client notify request ioctl

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

commit 7326fffb712f09a315bc73cc1ee63843f59b8bd4 upstream.

This patch address a possible security issue:

The request field in client notify request ioctl comes from user space
as u32 and is downcasted to u8 with out validation.
Check request field to have approved values
MEI_HBM_NOTIFICATION_STAR/STOP

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/main.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/misc/mei/main.c
+++ b/drivers/misc/mei/main.c
@@ -458,7 +458,11 @@ static int mei_ioctl_client_notify_reque
 {
 	struct mei_cl *cl = file->private_data;
 
-	return mei_cl_notify_request(cl, file, request);
+	if (request != MEI_HBM_NOTIFICATION_START &&
+	    request != MEI_HBM_NOTIFICATION_STOP)
+		return -EINVAL;
+
+	return mei_cl_notify_request(cl, file, (u8)request);
 }
 
 /**


Patches currently in stable-queue which might be from alexander.usyskin@intel.com are

queue-4.4/mei-validate-request-value-in-client-notify-request-ioctl.patch