release/4.8.25/drm-vmwgfx-fix-integer-overflow-in-vmw_surface_defin.patch

From bfa66065a1032c9c46fd8d277a0d922e0fb442d1 Mon Sep 17 00:00:00 2001
From: Li Qiang <liq3ea@gmail.com>
Date: Mon, 27 Mar 2017 20:10:53 -0700
Subject: [PATCH] drm/vmwgfx: fix integer overflow in
 vmw_surface_define_ioctl()

commit e7e11f99564222d82f0ce84bd521e57d78a6b678 upstream.

In vmw_surface_define_ioctl(), the 'num_sizes' is the sum of the
'req->mip_levels' array. This array can be assigned any value from
the user space. As both the 'num_sizes' and the array is uint32_t,
it is easy to make 'num_sizes' overflow. The later 'mip_levels' is
used as the loop count. This can lead an oob write. Add the check of
'req->mip_levels' to avoid this.

Cc: <stable@vger.kernel.org>
Signed-off-by: Li Qiang <liqiang6-s@360.cn>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
index 8423f0f46b27..27f0c3b06cd0 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
@@ -715,8 +715,11 @@ int vmw_surface_define_ioctl(struct drm_device *dev, void *data,
 			128;
 
 	num_sizes = 0;
-	for (i = 0; i < DRM_VMW_MAX_SURFACE_FACES; ++i)
+	for (i = 0; i < DRM_VMW_MAX_SURFACE_FACES; ++i) {
+		if (req->mip_levels[i] > DRM_VMW_MAX_MIP_LEVELS)
+			return -EINVAL;
 		num_sizes += req->mip_levels[i];
+	}
 
 	if (num_sizes > DRM_VMW_MAX_SURFACE_FACES * DRM_VMW_MAX_MIP_LEVELS ||
 	    num_sizes == 0)
-- 
2.12.0