drm/amdgpu: avoid a possible array overflow

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.

Workaround for bug:
https://bugs.freedesktop.org/show_bug.cgi?id=97460

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c
index 983175363b06..151422307d31 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;