drm/i915/bios: fix off by one in parse_generic_dtd()

The "num_dtd" variable is the number of elements in the
generic_dtd->dtd[] array so the > needs to be >= to prevent reading one
element beyond the end of the array.

Fixes: bd3610195565 ("drm/i915/vbt: Handle generic DTD block")
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191212091130.zf2g53njf5u24wk6@kili.mountain

diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
index bd674fd355b77da4e47c43525dddefd4a621cc89..54c02debeddf9d253ddfcca44d84cd430447aa45 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_bios.c
+++ b/drivers/gpu/drm/i915/display/intel_bios.c
@@ -340,7 +340,7 @@ parse_generic_dtd(struct drm_i915_private *dev_priv,
 
        num_dtd = (get_blocksize(generic_dtd) -
                   sizeof(struct bdb_generic_dtd)) / generic_dtd->gdtd_size;
-       if (dev_priv->vbt.panel_type > num_dtd) {
+       if (dev_priv->vbt.panel_type >= num_dtd) {
                DRM_ERROR("Panel type %d not found in table of %d DTD's\n",
                          dev_priv->vbt.panel_type, num_dtd);
                return;