From dd2351da7c438eb3d5f64a161cf3483648725dcd Mon Sep 17 00:00:00 2001
From: Rob Clark <rob@ti.com>
Date: Sun, 18 Sep 2011 14:38:15 -0500
Subject: drm: drm_ioctl() should zero-init extra data

If an older userspace passes in a smaller arg than the current kernel
ioctl arg struct, then extra fields should be initialized to zero
rather than passing random data to the DRM driver.

Signed-off-by: Rob Clark <rob@ti.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 93a112d..7a87e08 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -438,6 +438,8 @@ long drm_ioctl(struct file *filp,
 					goto err_i1;
 				}
 			}
+			if (asize > usize)
+				memset(kdata + usize, 0, asize - usize);
 		}
 
 		if (cmd & IOC_IN) {
-- 
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