Commit 8a783896 authored Dec 21, 2011 by Xi Wang Committed by Dave Airlie Dec 22, 2011

vmwgfx: fix incorrect VRAM size check in vmw_kms_fb_create()



Commit e133e737 didn't correctly fix the integer overflow issue.

-	unsigned int required_size;
+	u64 required_size;
	...
	required_size = mode_cmd->pitch * mode_cmd->height;
-	if (unlikely(required_size > dev_priv->vram_size)) {
+	if (unlikely(required_size > (u64) dev_priv->vram_size)) {

Note that both pitch and height are u32.  Their product is still u32 and
would overflow before being assigned to required_size.  A correct way is
to convert pitch and height to u64 before the multiplication.

	required_size = (u64)mode_cmd->pitch * (u64)mode_cmd->height;

This patch calls the existing vmw_kms_validate_mode_vram() for
validation.

Signed-off-by: Xi Wang <xi.wang@gmail.com>
Reviewed-and-tested-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

parent 77e00f2e

drivers/gpu/drm/vmwgfx/vmwgfx_kms.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -1093,7 +1093,6 @@ static struct drm_framebuffer vmw_kms_fb_create(struct drm_device dev,
		struct vmw_surface *surface = NULL;
		struct vmw_dma_buffer *bo = NULL;
		struct ttm_base_object *user_obj;
		u64 required_size;
		int ret;

		/**
		@@ -1102,8 +1101,9 @@ static struct drm_framebuffer vmw_kms_fb_create(struct drm_device dev,
		* requested framebuffer.
		*/

		required_size = mode_cmd->pitch * mode_cmd->height;
		if (unlikely(required_size > (u64) dev_priv->vram_size)) {
		if (!vmw_kms_validate_mode_vram(dev_priv,
		mode_cmd->pitch,
		mode_cmd->height)) {
		DRM_ERROR("VRAM size is too small for requested mode.\n");
		return ERR_PTR(-ENOMEM);
		}