[PATCH] drm/amdgpu: avoid a possible array overflow

[Alex Deucher]

When looking up the connector type make sure the index
is valid.  Avoids a later crash if we read past the end
of the array.

Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
Cc: stable at vger.kernel.org
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c
index 9831753..1514223 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c
@@ -321,6 +321,12 @@ bool amdgpu_atombios_get_connector_info_from_object_table(struct amdgpu_device *
 			    (le16_to_cpu(path->usConnObjectId) &
 			     OBJECT_TYPE_MASK) >> OBJECT_TYPE_SHIFT;
 
+			if (con_obj_id >= ARRAY_SIZE(object_connector_convert)) {
+				DRM_ERROR("invalid con_obj_id %d for device tag 0x%04x\n",
+					  con_obj_id, le16_to_cpu(path->usDeviceTag));
+				continue;
+			}
+
 			connector_type =
 				object_connector_convert[con_obj_id];
 			connector_object_id = con_obj_id;
-- 
2.5.5