From cea6e6e8717e81de266aa496f44088b2b960aa32 Mon Sep 17 00:00:00 2001 From: Dmitry Baryshkov Date: Tue, 6 Jan 2026 05:09:57 +0200 Subject: [PATCH] drm/atomic: verify that gamma/degamma LUTs are not too big The kernel specifies LUT table sizes in a separate property, however it doesn't enforce it as a maximum. Some drivers implement max size check on their own in the atomic_check path. Other drivers simply ignore the issue. Perform LUT size validation in the generic place. Reviewed-by: Thomas Zimmermann Link: https://patch.msgid.link/20260106-drm-fix-lut-checks-v3-3-f7f979eb73c8@oss.qualcomm.com Signed-off-by: Dmitry Baryshkov --- drivers/gpu/drm/drm_atomic_uapi.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c index dff1fdefcbeb..dc013a22bf26 100644 --- a/drivers/gpu/drm/drm_atomic_uapi.c +++ b/drivers/gpu/drm/drm_atomic_uapi.c @@ -413,10 +413,19 @@ static int drm_atomic_crtc_set_property(struct drm_crtc *crtc, } else if (property == config->prop_vrr_enabled) { state->vrr_enabled = val; } else if (property == config->degamma_lut_property) { + const size_t elem_size = sizeof(struct drm_color_lut); + u64 lut_size; + + ret = drm_object_immutable_property_get_value(&crtc->base, + config->degamma_lut_size_property, + &lut_size); + if (ret) + return ret; + ret = drm_property_replace_blob_from_id(dev, &state->degamma_lut, val, - -1, -1, sizeof(struct drm_color_lut), + elem_size * lut_size, -1, elem_size, &replaced); state->color_mgmt_changed |= replaced; return ret; @@ -429,10 +438,19 @@ static int drm_atomic_crtc_set_property(struct drm_crtc *crtc, state->color_mgmt_changed |= replaced; return ret; } else if (property == config->gamma_lut_property) { + const size_t elem_size = sizeof(struct drm_color_lut); + u64 lut_size; + + ret = drm_object_immutable_property_get_value(&crtc->base, + config->gamma_lut_size_property, + &lut_size); + if (ret) + return ret; + ret = drm_property_replace_blob_from_id(dev, &state->gamma_lut, val, - -1, -1, sizeof(struct drm_color_lut), + elem_size * lut_size, -1, elem_size, &replaced); state->color_mgmt_changed |= replaced; return ret; -- 2.47.3