From 61aff74833b86c735ee901c1038f0cbfcd606ae7 Mon Sep 17 00:00:00 2001
From: Xi Wang <xi.wang@gmail.com>
Date: Wed, 23 Nov 2011 01:12:01 -0500
Subject: drm: integer overflow in drm_mode_dirtyfb_ioctl()

commit a5cd335165e31db9dbab636fd29895d41da55dd2 upstream.

There is a potential integer overflow in drm_mode_dirtyfb_ioctl()
if userspace passes in a large num_clips.  The call to kmalloc would
allocate a small buffer, and the call to fb->funcs->dirty may result
in a memory corruption.

Reported-by: Haogang Chen <haogangchen@gmail.com>
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 include/drm/drm_mode.h | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'include/drm/drm_mode.h')

diff --git a/include/drm/drm_mode.h b/include/drm/drm_mode.h
index c4961ea50a4..53dfa1098b9 100644
--- a/include/drm/drm_mode.h
+++ b/include/drm/drm_mode.h
@@ -233,6 +233,8 @@ struct drm_mode_fb_cmd {
 #define DRM_MODE_FB_DIRTY_ANNOTATE_FILL 0x02
 #define DRM_MODE_FB_DIRTY_FLAGS         0x03
 
+#define DRM_MODE_FB_DIRTY_MAX_CLIPS     256
+
 /*
  * Mark a region of a framebuffer as dirty.
  *
-- 
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