[3.11.y.z extended stable] Patch "drm: fix NULL pointer access by wrong ioctl" has been added to staging queue

[Luis Henriques]

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

    drm: fix NULL pointer access by wrong ioctl

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

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

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 9b577bc14cbe2088d3eca739c9b22470d098c3f1 Mon Sep 17 00:00:00 2001
From: Zhaowei Yuan <zhaowei.yuan at samsung.com>
Date: Wed, 18 Jun 2014 14:33:59 +0800
Subject: drm: fix NULL pointer access by wrong ioctl

commit 1539fb9bd405ee32282ea0a38404f9e008ac5b7a upstream.

If user uses wrong ioctl command with _IOC_NONE and argument size
greater than 0, it can cause NULL pointer access from memset of line
463. If _IOC_NONE, don't memset to 0 for kdata.

Signed-off-by: Zhaowei Yuan <zhaowei.yuan at samsung.com>
Reviewed-by: David Herrmann <dh.herrmann at gmail.com>
Signed-off-by: Dave Airlie <airlied at redhat.com>
[ luis: backported to 3.11: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/gpu/drm/drm_drv.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
 mode change 100644 => 100755 drivers/gpu/drm/drm_drv.c

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
old mode 100644
new mode 100755
index 6dd71735cab4..d71e1a46c4d4
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -460,8 +460,9 @@ long drm_ioctl(struct file *filp,
 				retcode = -EFAULT;
 				goto err_i1;
 			}
-		} else
+		} else if (cmd & IOC_OUT) {
 			memset(kdata, 0, usize);
+		}

 		if (ioctl->flags & DRM_UNLOCKED)
 			retcode = func(dev, kdata, file_priv);
--
1.9.1