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: v3.15.5~76
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=6fe5d7d9b99de2b295cfc81b91c5abd279b9be2e;p=people%2Fms%2Flinux.git

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@samsung.com>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 03711d00aaae..8218078b6133 100644
--- 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);