From: Zhaowei Yuan <zhaowei.yuan@samsung.com>
Date: Wed, 18 Jun 2014 06:33:59 +0000 (+0800)
Subject: drm: fix NULL pointer access by wrong ioctl
X-Git-Tag: firefly_0821_release~176^2~3673^2~15
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=1539fb9bd405ee32282ea0a38404f9e008ac5b7a;p=firefly-linux-kernel-4.4.55.git

drm: fix NULL pointer access by wrong ioctl

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@samsung.com>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
---

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
old mode 100644
new mode 100755
index 03711d00aaae..8218078b6133
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -419,8 +419,9 @@ 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);