4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>
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@xxxxxxxxx>
Signed-off-by: Tomas Winkler <tomas.winkler@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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);
}
/**
--
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