[PATCH 5.10 44/74] drm/i915/overlay: Prevent divide by zero bugs in scaling

Greg Kroah-Hartman
2022-02-07T11:37:43Z

From: Dan Carpenter <dan.carpenter@oracle.com>

commit 90a3d22ff02b196d5884e111f39271a1d4ee8e3e upstream.

Smatch detected a divide by zero bug in check_overlay_scaling().

drivers/gpu/drm/i915/display/intel_overlay.c:976 check_overlay_scaling()
error: potential divide by zero bug '/ rec->dst_height'.
drivers/gpu/drm/i915/display/intel_overlay.c:980 check_overlay_scaling()
error: potential divide by zero bug '/ rec->dst_width'.

Prevent this by ensuring that the dst height and width are non-zero.

Fixes: 02e792fbaadb ("drm/i915: implement drmmode overlay support v4")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220124122409.GA31673@kili
(cherry picked from commit cf5b64f7f10b28bebb9b7c9d25e7aee5cbe43918)
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/gpu/drm/i915/display/intel_overlay.c | 3 +++
1 file changed, 3 insertions(+)

--- a/drivers/gpu/drm/i915/display/intel_overlay.c
+++ b/drivers/gpu/drm/i915/display/intel_overlay.c
@@ -932,6 +932,9 @@ static int check_overlay_dst(struct inte
const struct intel_crtc_state *pipe_config =
overlay->crtc->config;

+ if (rec->dst_height == 0 || rec->dst_width == 0)
+ return -EINVAL;
+
if (rec->dst_x < pipe_config->pipe_src_w &&
rec->dst_x + rec->dst_width <= pipe_config->pipe_src_w &&
rec->dst_y < pipe_config->pipe_src_h &&