[PATCH 4.9 47/96] drm/vmwgfx: Potential off by one in vmw_view_add()

From: Greg Kroah-Hartman
Date: Mon Jan 15 2018 - 07:44:33 EST


4.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

commit 0d9cac0ca0429830c40fe1a4e50e60f6221fd7b6 upstream.

The vmw_view_cmd_to_type() function returns vmw_view_max (3) on error.
It's one element beyond the end of the vmw_view_cotables[] table.

My read on this is that it's possible to hit this failure. header->id
comes from vmw_cmd_check() and it's a user controlled number between
1040 and 1225 so we can hit that error. But I don't have the hardware
to test this code.

Fixes: d80efd5cb3de ("drm/vmwgfx: Initial DX support")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Reviewed-by: Thomas Hellstrom <thellstrom@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c | 2 ++
1 file changed, 2 insertions(+)

--- a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
@@ -2729,6 +2729,8 @@ static int vmw_cmd_dx_view_define(struct
}

view_type = vmw_view_cmd_to_type(header->id);
+ if (view_type == vmw_view_max)
+ return -EINVAL;
cmd = container_of(header, typeof(*cmd), header);
ret = vmw_cmd_res_check(dev_priv, sw_context, vmw_res_surface,
user_surface_converter,