[PATCH] drm: Make sure that encoder_type for drm_encoder_init() is in the list

[Jordan Crouse]

If a encoder name isn't specified for drm_encoder_init() it will try
to construct one based on the incoming encoder_type identifier. If the
caller passes an invalid encoder_type value the lookup could walk right
past the end of the table.

Signed-off-by: Jordan Crouse <jcrouse at codeaurora.org>
---
 drivers/gpu/drm/drm_encoder.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/drm_encoder.c b/drivers/gpu/drm/drm_encoder.c
index 273e1c59c54a..4cf6c3bb8503 100644
--- a/drivers/gpu/drm/drm_encoder.c
+++ b/drivers/gpu/drm/drm_encoder.c
@@ -128,6 +128,12 @@ int drm_encoder_init(struct drm_device *dev,
 		encoder->name = kvasprintf(GFP_KERNEL, name, ap);
 		va_end(ap);
 	} else {
+		/* Make sure that the requested encoder type is in the list */
+		if (encoder_type >= ARRAY_SIZE(drm_encoder_enum_list)) {
+			ret = -EINVAL;
+			goto out_put;
+		}
+
 		encoder->name = kasprintf(GFP_KERNEL, "%s-%d",
 					  drm_encoder_enum_list[encoder_type].name,
 					  encoder->base.id);
-- 
2.17.1