blob: dec5c4a8342d99314650ceac28e4bd95a1192fe5 [file] [log] [blame]
* Copyright 2020 Google, LLC
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
#include "include/core/SkCanvas.h"
#include "include/core/SkPaint.h"
#include "include/core/SkSurface.h"
#include "include/effects/SkRuntimeEffect.h"
#include "src/gpu/GrShaderCaps.h"
#include "fuzz/Fuzz.h"
static constexpr size_t kReservedBytes = 256;
* The fuzzer will take in the bytes and divide into two parts.
* original bytes : [... code bytes ... | 256 bytes]
* The first part is codeBytes, the original bytes minus 256 bytes, which will be treated
* as sksl code, intending to create SkRuntimeEffect.
* For the second part, it will first reserve 256 bytes and then allocate bytes with same size
* as effect->inputSize() to uniformBytes. The uniformBytes is intended to create makeShader().
* Note that if uniformBytes->size() != effect->inputSize() the shader won't be created.
* We fuzz twice, with two different settings for inlining in the SkSL compiler. By default, the
* compiler inlines most small to medium functions. This can hide bugs related to function-calling.
* So we run the fuzzer once with inlining disabled, and again with it enabled (aggressively).
* This gives us better coverage, and eases the burden on the fuzzer to inject useless noise into
* functions to suppress inlining.
static bool FuzzSkRuntimeEffect_Once(sk_sp<SkData> bytes, const SkRuntimeEffect::Options& options) {
if (bytes->size() < kReservedBytes) {
return false;
sk_sp<SkData> codeBytes = SkData::MakeSubset(bytes.get(), 0, bytes->size() - kReservedBytes);
SkString shaderText{static_cast<const char*>(codeBytes->data()), codeBytes->size()};
SkRuntimeEffect::Result result = SkRuntimeEffect::MakeForShader(shaderText, options);
SkRuntimeEffect* effect = result.effect.get();
if (!effect || effect->uniformSize() > kReservedBytes) { // if there is not enough uniform bytes
return false;
sk_sp<SkData> uniformBytes =
SkData::MakeSubset(bytes.get(), bytes->size() - kReservedBytes, effect->uniformSize());
auto shader = effect->makeShader(uniformBytes, /*children=*/nullptr, /*childCount=*/0,
/*localMatrix=*/nullptr, /*isOpaque=*/false);
if (!shader) {
return false;
SkPaint paint;
sk_sp<SkSurface> s = SkSurface::MakeRasterN32Premul(128, 128);
if (!s) {
return false;
return true;
bool FuzzSkRuntimeEffect(sk_sp<SkData> bytes) {
// Test once with the inliner disabled...
SkRuntimeEffect::Options options;
options.forceNoInline = true;
bool result = FuzzSkRuntimeEffect_Once(bytes, options);
// ... and then with the inliner enabled.
options.forceNoInline = false;
result = FuzzSkRuntimeEffect_Once(bytes, options) || result;
return result;
extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
if (size > 3000) {
return 0;
auto bytes = SkData::MakeWithoutCopy(data, size);
return 0;