[PATCH] drm/amd/display: Fix potential index out of bounds in color transformation function

[Srinivasan Shanmugam]

Fixes index out of bounds issue in the color transformation function.
The issue could occur when the index 'i' exceeds the number of transfer
function points (TRANSFER_FUNC_POINTS).

The fix adds a check to ensure 'i' is within bounds before accessing the
transfer function points. If 'i' is out of bounds, an error message is
logged and the function returns false to indicate an error.

Reported by smatch:
drivers/gpu/drm/amd/amdgpu/../display/dc/dcn10/dcn10_cm_common.c:405 cm_helper_translate_curve_to_hw_format() error: buffer overflow 'output_tf->tf_pts.red' 1025 <= s32max
drivers/gpu/drm/amd/amdgpu/../display/dc/dcn10/dcn10_cm_common.c:406 cm_helper_translate_curve_to_hw_format() error: buffer overflow 'output_tf->tf_pts.green' 1025 <= s32max
drivers/gpu/drm/amd/amdgpu/../display/dc/dcn10/dcn10_cm_common.c:407 cm_helper_translate_curve_to_hw_format() error: buffer overflow 'output_tf->tf_pts.blue' 1025 <= s32max

Fixes: b629596072e5 ("drm/amd/display: Build unity lut for shaper")
Cc: Vitaly Prosyak <vitaly.prosyak at amd.com>
Cc: Charlene Liu <Charlene.Liu at amd.com>
Cc: Harry Wentland <harry.wentland at amd.com>
Cc: Rodrigo Siqueira <Rodrigo.Siqueira at amd.com>
Cc: Roman Li <roman.li at amd.com>
Cc: Aurabindo Pillai <aurabindo.pillai at amd.com>
Cc: Tom Chung <chiahsuan.chung at amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam at amd.com>
---
 drivers/gpu/drm/amd/display/dc/dcn10/dcn10_cm_common.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_cm_common.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_cm_common.c
index b7e57aa27361..b0d192c6e63e 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_cm_common.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_cm_common.c
@@ -402,6 +402,11 @@ bool cm_helper_translate_curve_to_hw_format(struct dc_context *ctx,
 				i += increment) {
 			if (j == hw_points - 1)
 				break;
+			if (i >= TRANSFER_FUNC_POINTS) {
+				DC_LOG_ERROR("Index out of bounds: i=%d, TRANSFER_FUNC_POINTS=%d\n",
+					     i, TRANSFER_FUNC_POINTS);
+				return false;
+			}
 			rgb_resulted[j].red = output_tf->tf_pts.red[i];
 			rgb_resulted[j].green = output_tf->tf_pts.green[i];
 			rgb_resulted[j].blue = output_tf->tf_pts.blue[i];
-- 
2.34.1