[Intel-gfx] [PATCH v2 1/3] drm/i915: Reject panel_type > 0xf from VBT

[ville.syrjala at linux.intel.com]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

VBT can only contain 16 panel entries, indexed with the panel_type.
To play it safe we should reject panel_type > 0xf, so that we don't
read past the valid data.

v2: Add debug logging (Jani)

Cc: Jani Nikula <jani.nikula at linux.intel.com>
Cc: Rob Kramer <rob at solution-space.com>
Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
Reviewed-by: Jani Nikula <jani.nikula at intel.com> (v1)
---
 drivers/gpu/drm/i915/intel_bios.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index eb756c41d9e1..c8857b5dbfec 100644
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -212,8 +212,11 @@ parse_lfp_panel_data(struct drm_i915_private *dev_priv,
 		return;
 
 	dev_priv->vbt.lvds_dither = lvds_options->pixel_dither;
-	if (lvds_options->panel_type == 0xff)
+	if (lvds_options->panel_type > 0xf) {
+		DRM_DEBUG_KMS("Invalid VBT panel type 0x%x\n",
+			      lvds_options->panel_type);
 		return;
+	}
 
 	panel_type = lvds_options->panel_type;
 
-- 
2.7.4