drm: Warn if mode to umode conversion overflows the destination types

When converting from a drm_display_mode to drm_mode_modeinfo, print a
warning if the the timings values don't fit into the __u16 datatype.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index bbcecdb4e0ad..d11763f7211a 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -1002,6 +1002,13 @@ EXPORT_SYMBOL(drm_mode_config_cleanup);
 void drm_crtc_convert_to_umode(struct drm_mode_modeinfo *out,
                                struct drm_display_mode *in)
 {
+        WARN(in->hdisplay > USHRT_MAX || in->hsync_start > USHRT_MAX ||
+             in->hsync_end > USHRT_MAX || in->htotal > USHRT_MAX ||
+             in->hskew > USHRT_MAX || in->vdisplay > USHRT_MAX ||
+             in->vsync_start > USHRT_MAX || in->vsync_end > USHRT_MAX ||
+             in->vtotal > USHRT_MAX || in->vscan > USHRT_MAX,
+             "timing values too large for mode info\n");
+
         out->clock = in->clock;
         out->hdisplay = in->hdisplay;
         out->hsync_start = in->hsync_start;