6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Harry Wentland commit e4c3ab59021e7c146a84b6671f0d530972bd58b4 upstream. Unlike the CRTC degamma path, which is guarded by amdgpu_dm_verify_lut_sizes(), the per-plane degamma LUT size was never validated before use. __set_dm_plane_degamma() passed the user-supplied size straight into __is_lut_linear() and, for a non-linear LUT, into __set_input_tf() -> __drm_lut_to_dc_gamma(), the latter always iterating MAX_COLOR_LUT_ENTRIES entries regardless of the actual LUT size. A malformed AMD_PLANE_DEGAMMA_LUT blob (e.g. a single entry) could thus trigger a divide-by-zero in __is_lut_linear() or an out-of-bounds read in __drm_lut_to_dc_gamma(). Reject any plane degamma LUT whose size does not match MAX_COLOR_LUT_ENTRIES, mirroring the invariant the code already asserts a few lines below (and which the CRTC path enforces). The AMD_PLANE_DEGAMMA_LUT property is only exposed on builds with AMD_PRIVATE_COLOR defined. Fixes: 980f8710075a ("drm/amd/display: add plane degamma TF and LUT support") Cc: stable@vger.kernel.org Signed-off-by: Harry Wentland Reviewed-by: Melissa Wen Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c @@ -1149,6 +1149,13 @@ __set_dm_plane_degamma(struct drm_plane_ degamma_lut = __extract_blob_lut(dm_plane_state->degamma_lut, °amma_size); + if (degamma_lut && degamma_size != MAX_COLOR_LUT_ENTRIES) { + drm_dbg(plane_state->state->dev, + "Invalid Plane Degamma LUT size. Should be %u but got %u.\n", + MAX_COLOR_LUT_ENTRIES, degamma_size); + return -EINVAL; + } + has_degamma_lut = degamma_lut && !__is_lut_linear(degamma_lut, degamma_size);